Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/19/13
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
235 PM MST WED JUL 17 2013
.SYNOPSIS...
DEEP MONSOON MOISTURE WILL CONTINUE OVER ARIZONA...BUT SLOWLY EXPAND
WEST INTO THE SOUTHEAST CALIFORNIA DESERTS BY FRIDAY. THIS WILL
PROVIDE A THREAT OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
OVER ARIZONA TODAY AND THURSDAY...THEN INTO THE SOUTHEAST CALIFORNIA
DESERTS BY FRIDAY AND THE WEEKEND.
&&
.DISCUSSION...
CURRENT RADAR IMAGERY AS OF 2PM LOOKS MODERATELY ACTIVE OVER THE
MOGOLLON RIM AREA AND LOCATIONS FARTHER NORTHEAST.
NORTH-NORTHEASTERLY FLOW ALOFT IS CREATING DIFLUENCE FROM NORTHERN
ARIZONA STRETCHING SOUTHWARD ACROSS CENTRAL AND SOUTHERN ARIZONA.
COOLER AIR FROM NORTHEASTERN PORTIONS OF AZ IS BEING DRAWN SOUTHWEST
ACROSS THE DESERTS...INTO AMPLE MOISTURE LOADING ENVIRONMENTS.
PAIRED WITH SUFFICIENT DAYTIME HEATING TAKING PLACE...THIS SHOULD
CREATE A FAVORABLE ENVIRONMENT FOR THUNDERSTORM ACTIVITY AND
INCREASED MONSOON ACTIVITY THIS EVENING. FORECAST MODELS ARE SHOWING
15-25KT OF STEERING FLOW...WHICH WOULD TRANSLATE TO FASTER MOVING
STORMS AND NOT SO MUCH THE THREAT OF HEAVY RAIN PRODUCING STORMS.
LOCATIONS THAT ARE OF INTEREST FOR TONIGHT ARE LA PAZ AND YUMA
COUNTIES AND THE WESTERN PORTION OF MARICOPA COUNTY...WHERE A MORE
FAVORABLE INSTABILITY AXIS RESIDES. GUSTY WINDS GENERATED FROM
OUTFLOWS ARE ALSO CONCERNS.
RAOB SOUNDING PRECIPITABLE WATER VALUES REMAIN PRETTY MOIST...VALUES
RANGING FROM 1 TO 1.8 INCHES ACROSS ARIZONA...WITH INCREASING
MOISTURE ALONG THE WESTERN PORTIONS OF THE STATE. AIRCRAFT SOUNDINGS
INDICATE A SHALLOW WARM LAYER INVERSION AROUND 700HPA EXISTED AT
19Z AND HAS SINCE ERODED AWAY. DEWPOINT READINGS ACROSS THE CENTRAL
DESERTS HAVE TRENDED DOWNWARD 4-5F DEGREES OVER THE PAST 24
HOURS...WHILE STILL REMAINING NEAR 60F. SKIES HAVE CLEARED
CONSIDERABLY TODAY...ALLOWING TEMPERATURES A LONGER DURATION TO WARM
AND MORE INSTABILITY TO DEVELOP. THE HRRR AND WRF LOCAL FORECAST
MODELS HAVE BEEN PERFORMING WELL IN REGARDS TO THE GENERAL LOCATION
AND MOVEMENT WITH CONVECTION INITIATION. THIS SAID...THESE MODELS
INDICATE A LATER ONSET OF ACTIVITY THIS AFTERNOON. WHILE WIDESPREAD
THUNDERSTORM ACTIVITY IS NOT ANTICIPATED...ANOTHER ACTIVE MONSOON
DAY IS EXPECTED. SKY HARBOR HAS REACHED 99 DAYS WITHOUT MEASURABLE
PRECIPITATION AS OF TUESDAY 16 JULY.
THE NEXT FEW DAYS LOOK FAVORABLE FOR AFTERNOON THUNDERSTORM ACTIVITY
AS WELL...AS THE UPPER LEVEL CLOSED LOW CONTINUES TO TREK
WEST-SOUTHWESTWARD INTO NORTHWEST MEXICO/GULF OF CA. SOUTHWEST AZ
WILL SEE AN INCREASE IN THE THREAT FOR STORMS THURSDAY AFTERNOON.
AS MENTIONED BY THE PREVIOUS SHIFT...FRIDAY THROUGH EARLY NEXT
WEEK...THERE WILL BE AN INCREASING THREAT OF SHOWERS AND
THUNDERSTORMS OVER THE SOUTHEAST CA DESERTS AND MOUNTAINS THIS
PERIOD. THE NORTHWEST MEXICO CLOSED LOW WILL EVENTUALLY MOVE TO A
POSITION OFF THE SAN DIEGO COAST BY MONDAY. IN THIS POSITION...UPPER
LEVEL WINDS BECOME SOUTHEASTERLY WITH A SERIES OF EMBEDDED AND HARD
TO TIME DISTURBANCES. THEREFORE A THREAT OF STORMS IN GENERAL WILL
EXIST REGION WIDE...WITH DAY TO DAY CHANGES IN COVERAGE AND
INTENSITY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
EXPECT MID AND HIGH CLOUDS TO GRADUALLY THICKEN AND LOWER AS THE
AFTERNOON PROGRESSES AND AS STORMS MAKE THEIR WAY INTO THE VALLEY
FROM THE RIM. WILL MAINTAIN VCSH/VCTS AT ALL PHOENIX SITES SHORTLY
AFTER 00-02Z...CONFIDENCE IN RAIN AT ANY GIVEN AIRPORT SHAKY AT
BEST. VERY TOUGH CALL IF WE WILL GET A WEST WIND TODAY...MODEL
GUIDANCE SUGGESTS IF WE DO IT WILL BE VERY BRIEF. WINDS WILL QUICKLY
RETURN TO EAST BY MID EVENING WITH CLOUDS LINGERING INTO THURSDAY
MORNING.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SCT-BKN HIGH CLOUDS JUST ABOUT THE ONLY AVIATION CONCERN ACROSS SE
CA. PRECIP CHANCES REMAIN SLIM TO NIL. WINDS WILL BE LIGHT AND WILL
FAVOR TYPICAL DIURNAL TRENDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY THROUGH THE
WEEKEND AS A QUASI-STATIONARY AREA OF LOW PRESSURE REMAINS OVER THE
AREA. DEEPER MONSOONAL MOISTURE WILL WORK WESTWARD THROUGH THE
WEEKEND...GENERATING SLIGHTLY COOLER TEMPERATURES AND EXPANDING
PRECIPITATION CHANCES INTO THE SOUTHEAST CALIFORNIA DISTRICTS.
HUMIDITIES WILL ALSO REMAIN ELEVATED WITH AFTERNOON HUMIDITIES ONLY
DROPPING INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY.
STORM COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL
IMPACT FORECAST WINDS...DISRUPTING NORMAL DIURNAL PATTERNS.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...CDEWEY
AVIATION...LEINS
FIRE WEATHER...NOLTE/LEINS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
806 PM MDT THU JUL 18 2013
.UPDATE...RAIN SHOWERS AND THUNDERSTORMS WILL CONTINUE TO SLOWLY
SHIFT EASTWARD THROUGH THE EVENING OVER LARIMER AND WELD COUNTIES.
THEY ARE THEN EXPECTED TO DIMINISH AFTER MIDNIGHT. INCREASED POPS
FOR EASTERN LARIMER COUNTIES EASTWARD THROUGH LOGAN AND MORGAN
COUNTIES. ELSEWHERE...ISOLATED CONVECTION IS ANTICIPATED AT BEST
AND THUS DECREASED POPS FOR TONIGHT. MOISTURE WILL REMAIN IN PLACE
AND BRING ANOTHER CHANCE FOR STORMS FRIDAY.
&&
.AVIATION...STILL A SLIGHT CHANCE FOR A THUNDERSTORM IN THE DENVER
AREA THROUGH 06Z...THOUGH THE CHANCES ARE VERY LOW. NORTHWEST
WINDS WILL TURN CLOCKWISE TONIGHT AND FRIDAY MORNING AND SETTLE AT
AN EASTERLY DIRECTION FRIDAY AFTERNOON. THERE WILL BE BETTER
CHANCE FOR THUNDERSTORMS FRIDAY...VERY HEAVY RAIN AND WIND GUSTS
TO 40 KNOTS WILL BE THE MAIN THREATS.
&&
.PREV DISCUSSION... /ISSUED 319 PM MDT THU JUL 18 2013/
SHORT TERM...SLOW MOVING THUNDERSTORMS AN ISSUE OVER LARIMER
COUNTY THIS AFTN. FLASH FLOODING REPORTED IN THE FERN LAKE BURN
SCAR THIS AFTN WHERE RADAR ESTIMATED 1.5 TO 2.5 INCH STORM TOTALS.
SIMILAR ISSUES WILL CONTINUE THE REST THE AFTERNOON AND EVENING
ESPECIALLY IN THE FOOTHILLS OF LARIMER AND BOULDER COUNTIES. STORM
MOTIONS 10 KTS OR LESS THIS AFTN WITH PW VALUES CLOSE TO ONE INCH.
16Z HRRR KEEPS THE BEST CONVERGE ALONG AND NORTH OF INTERSTATE 70
AND 76 TONIGHT...SO WILL GO WITH THE HIGHEST COVERAGE THERE. ON
FRIDAY IT WILL BE COOLER FOLLOWING THE PASSAGE OF A COLD FRONT
TONIGHT. SPATIAL CROSS SECTIONS SHOW A DEEPER EASTERLY FLOW WITH
SIMILAR PW VALUES FOR FRIDAY AFTN. AS A RESULT...SLOW MOVING
THUNDERSTORMS WITH HEAVY RAIN AND FLASH FLOODING WILL AGAIN BE AN
ISSUE ESPECIALLY IN THE BURN AREAS...BUT IN OTHER POOR DRAINAGE
AREAS AS WELL. NO FLASH FLOOD WATCH AT THIS TIME...BUT ONE MAY BE
NEEDED FOR FRIDAY AT SOME POINT.
LONG TERM...ONLY MINOR CHANGES TODAY. UPPER RIDGE REMAINS OVER
MOST OF THE COUNTRY. DRIER AIR WORKS IN FROM THE NORTHWEST ON
SUNDAY FOR WARMER AND NEARLY DRY WEATHER...THEN BY LATE IN THE
WEEK MOISTURE COMES UP FROM THE SOUTH AGAIN. THIS IS ALREADY
COVERED WELL...MINOR CHANGES IN MODEL CONSENSUS LOOK FINE.
AVIATION...16Z HRRR MDL WANT TO KEEP THE HIGHEST TSTM COVERAGE
TO THE NORTH AND WEST OF DENVER THIS EVENING SO IT MAY BE BEST TO
GO WITH VCTS THIS AFTN SO HOLD OFF ON THE TEMPO GROUP FOR TSTMS
FOR THE 00Z TAFS. WILL WATCH THE NEXT COUPLE OF HRRR RUNS AND SEE
HOW THEY HANDLE OUTFLOW BOUNDARIES AND THE CONSEQUENT CONVECTION
OFF THE FOOTHILLS BEFORE MAKING A DECISION. A COOLER AMS WILL BE
OVER THE AREA ON FRIDAY FOLLOWING THE COLD FRONT TONIGHT. FLOW AT
THE SFC AND ALOFT WILL BE EASTERLY FOR FRIDAY AFTN...WITH A BETTER
CHANCE OF TSTMS WEST OF INTERSTATE 25.
HYDROLOGY...THREAT FOR FLASH FLOODING WILL BE AN ISSUE IN THROUGH
04Z THIS EVENING...WITH ANOTHER POSSIBILITY FOR FLASH FLOODING IN
THE BURN AREAS FRIDAY AFTN. STORM MOTIONS A LITTLE ERRATIC THIS
AFTN WITH SPEEDS OF 6-10KTS...WITH SLOW MOVEMENT AGAIN EXPECTED
FRIDAY AFTN WITH STORM MOTION EXPECTED TO BE NE TO SW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....GIMMESTAD
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
134 AM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS WEEK WITH ONLY WIDELY
SCATTERED SHOWERS OR THUNDERSTORMS ON WED. CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE THU...FRI AND ESPECIALLY SAT AS A
COLD FRONT APPROACHES FROM THE GREAT LAKES. RELIEF FROM THE HEAT
AND HUMIDITY WILL ARRIVE ON SUNDAY BEHIND A STRONG COLD FRONT AND
LAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
130 AM UPDATE...
MAINLY SKC CONDITIONS ACROSS THE REGION THIS HOUR AS REMNANT
CONVECTIVE CLOUDS HAVE ALREADY DISSIPATED. NOT EXPECTING ANY MORE
CLOUD COVER THROUGH THE MORNING...SO TEMPS MAY CONTINUE TO DECLINE
A FEW MORE HOURS AND DIP TO THE UPPER 60S IN SEVERAL LOCATIONS
BEFORE REBOUNDING AFTER SUNRISE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
WED WILL BE SIMILAR TO TODAY...WITH A MOSTLY CLEAR START AND
TEMPERATURES RAPIDLY CLIMBING INTO THE LOWER TO MID 90S.
TEMPERATURES WILL BE A COUPLE OF DEGREES WARMER AND DEWPOINTS WILL
BE A DEGREE OR TWO HIGHER...WHICH WILL LEAD TO HEAT INDICES
REACHING 98-102 OVER MOST OF SOUTHERN NEW ENGLAND...INCLUDING
SOUTHERN NH...WITH THE ONLY EXCEPTIONS BEING CAPE COD AND THE
ISLANDS. THUS HAVE ISSUED A HEAT ADVISORY FOR MOST OF THE REGION
FOR WED AFTERNOON AND EARLY EVENING.
WINDS WILL STILL BE LIGHT...BUT SHOULD TURN TO A SOUTHERLY
DIRECTION. ALTHOUGH HIGHS REACHED 90 ON BLOCK ISLAND TODAY...WITH
LIGHT SOUTHERLY WINDS EXPECTED OFF OF THE COOLER WATERS WED...HAVE
ONLY FORECAST MID 80S THERE...IT COULD POTENTIALLY BE COOLER THAN
THAT.
THERE IS A CHANCE OF AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS
ON WED...MAINLY IN SOUTHERN NH AND NORTHERN MA...AS LOW PRESSURE
MOVES ACROSS SOUTHERN QUEBEC AND A TROUGH OF LOW PRESSURE PASSES
ACROSS NEW ENGLAND. UPPER LEVEL HIGH PRES RIDGE STILL IN CONTROL
THOUGH WITH CAP AROUND H7 AND UNFAVORABLE MID LEVEL LAPSE RATES.
SB CAPE VALUES LOOK TO BE A BIT HIGHER THANKS TO THE INCREASING
MOISTURE WITHIN THE COLUMN...AVERAGING ABOUT 1500-2000 J/KG.
THEREFORE...WENT WITH 25 TO 35 PCT CHANCE IN NORTHEAST MA/SOUTHERN
NH AND 20 PCT FARTHER TO THE SOUTH INTO NORTHERN CT/RI/SOUTHEAST
MA.
WEDNESDAY EVENING...ANY CONVECTION WILL DIMINISH AGAIN BY SUNSET.
ANOTHER WARM AND MUGGY NIGHT WITH CLEAR TO PARTLY CLOUDY SKIES IS
EXPECTED. PERHAPS A LITTLE MORE PATCHY FOG AS THE AIR MASS GETS
EVEN MORE HUMID. LOWS MAINLY UPPER 60S TO MID 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HEADLINES...
* HOT/HUMID THU INTO SAT WITH SCATTERED T-STORMS
* SEVERE STORMS POSSIBLE AHEAD OF A COLD FRONT SAT
* SEASONABLE AND DRY SUNDAY INTO THE BEGINNING OF NEXT WEEK
DETAILS...
NOT MUCH CHANGE IN OUR FORECAST THINKING FROM PREVIOUS SHIFTS.
MODELS REMAIN IN GOOD OVERALL AGREEMENT SHIFTING H5 HIGH SOUTH
AND WEST TOWARDS THE FOUR-CORNERS REGION ALLOWING FOR FALLING
HEIGHTS ACROSS NEW ENGLAND. THIS RESULTS IN THE RETURN OF THE
NORTHERN STREAM AS DOMINANT INFLUENCE AND SUBSEQUENTLY A MORE
ACTIVE PATTERN.
THURSDAY...
MODELS KEY ON LEE TROUGH BECOMING FOCUS FOR SCATTERED AFTERNOON
CONVECTION. SURFACE-BASED CAPES REACH 1500 J/KG WITH DECENT MID
LEVEL LAPSE RATES AROUND 6C/KM...BUT 0-6KM SHEAR IS MARGINAL AT
BEST. STILL NEED TO OVERCOME RATHER WARM MID LEVEL TEMPERATURES...
SO NOT CONFIDENT THAT STORM COVERAGE WILL BE ALL THAT GREAT. KEPT
CHANCE POPS FOR SCATTERED AFTERNOON THUNDERSTORMS WITH CONTINUED
MENTION OF HEAVY RAIN.
HIGH CAPE ENVIRONMENT FAVORS STRONG TO ISOLATED SEVERE STORMS...
BUT OVERALL SEVERE THREAT APPEARS TO BE LIMITED. PRECIPITABLE
WATER VALUES APPROACHING 2 INCHES...WHICH IS AROUND +2 STANDARD
DEVIATIONS...MEANS POTENTIAL FOR HEAVY RAINFALL AND ISOLATED
FLOODING IN STORMS.
HIGHS IN 90S AWAY FROM S COAST COMBINED WITH DEW POINTS IN LOWER
70S WILL ONCE AGAIN YIELD HEAT INDICES AROUND 100.
FRIDAY...
FLOW ALOFT BECOMES FLATTER WHICH SHOULD ALLOW ANY UPSTREAM
ACTIVITY TO PASS TO OUR N. HOWEVER WE REMAIN IN UNSTABLE AIRMASS
WITH BETTER CONVECTIVE POTENTIAL THAN THU. MODELS SHOW SURFACE
BASED CAPES 2000-3000 J/KG AND MID LEVEL LAPSE RATES OVER 6C/KM.
AXIS OF GREATEST 0-6KM SHEAR REMAINS ACROSS NORTHERN NEW ENGLAND
BUT SW NH AND NORTHERN MA ARE ON PERIPHERY OF THIS AXIS WITH
VALUES OF 30-35KT. IN ADDITION WE ARE IN FAVORABLE RR QUAD OF
UPPER JET. ONLY LIMITING FACTOR APPEARS TO BE WARM MID LEVEL TEMPS
/+11C AT 700 MB/ BUT COLDER AIR ALOFT SHOULD BE ABLE TO
COMPENSATE.
EXPECT SCATTERED STORMS TO DEVELOP FRI AFTERNOON ACROSS MUCH OF
SOUTHERN NEW ENGLAND...ASIDE FROM IMMEDIATE S COAST WHICH WILL BE
MORE STABLE DUE TO SW FLOW. SEVERE POTENTIAL IS SOMEWHAT BETTER
THAN THU WITH BETTER POSSIBILITY OF DAMAGING WINDS DUE TO BOWING
SEGMENTS OR LINES. ALSO HAVE CONTINUED POTENTIAL FOR HEAVY
RAINFALL AND ISOLATED FLOODING.
INCREASING SW FLOW WILL RESULT IN WARMER DAY THAN THU. HIGHS
SHOULD TOP OUT IN LOW-MID 90S /GIVEN MODEL 2M TEMPERATURES/
COMBINED WITH DEW POINTS IN LOW-MID 70S SHOULD YIELD HEAT INDICES
OF 100-105. NOT CONFIDENT ENOUGH TO ISSUE EXCESSIVE HEAT WATCH BUT
WE MAY NEED TO DO SO IF THIS BECOMES MORE CERTAIN.
SATURDAY...
BEST POTENTIAL FOR ORGANIZED CONVECTION AS STRONG COLD FRONT
APPROACHES FROM GREAT LAKES. SOME QUESTION AS TO WHETHER OR NOT
ANY EARLY MORNING CONVECTION WILL INHIBIT SIGNIFICANT
DESTABILIZATION DURING AFTERNOON. PATTERN SEEMS TO FAVOR AT LEAST
MORNING SHOWERS/STORMS NEAR S COAST...THEN WE SEE A BREAK BEFORE
ADDITIONAL STORMS FIRE DURING AFTERNOON AND EVENING.
NO REAL CHANGE IN THINKING FROM SPC DAY 4 OUTLOOK AND PREVIOUS
DISCUSSION. EXPECTED INSTABILITY COUPLED WITH BULK SOUTHWESTERLY
UNI-DIRECTIONAL SHEAR AROUND 35 KTS FAVORS MULTICELLS AND LINE
ECHO WAVE PATTERNS WITH DAMAGING WINDS MAIN THREAT. ALSO NEED TO
BE AWARE OF CONTINUED FLASH FLOOD POTENTIAL WITH PRECIPITABLE
WATER VALUES NEAR 2 INCHES.
SUNDAY INTO THE EARLY WEEK...
COLD FRONT WILL HEAD OFFSHORE SUN MORNING...PERHAPS NOT UNTIL SUN
AFTERNOON ON CAPE COD. COOLER AND DRIER AIR WILL FOLLOW ON NW
WINDS LATER SUN. FRONT MAY BECOME STATIONARY AS IT RUNS UP INTO
RIDGING OVER WESTERN ATLANTIC. THIS WOULD KEEP US IN NE FLOW
MON/TUE WITH DRY WEATHER ANTICIPATED...ALTHOUGH IT IS POSSIBLE ONE
OR TWO WEAK AREAS OF LOW PRESSURE COULD COME CLOSE ENOUGH TO BRING
AT LEAST SOME CLOUDINESS TO SE NEW ENGLAND.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH THURSDAY.
MAINLY VFR THROUGH THE DAY TODAY. SEA BREEZES LIKELY ALONG
EASTERN SHORE BUT WINDS WILL GRADUALLY SHIFT BACK TO THE
SOUTH/SOUTHWEST BY LATE IN THE DAY. MOST OF THE AFTERNOON SHOWERS
AND THUNDERSHOWERS REMAIN IN NORTHERN NEW ENGLAND...BUT AN
ISOLATES SHOWER OR STORM MAY SNEAK INTO SOUTHERN NH OR NORTHERN MA
BY LATE DAY/EVENING.
OVERNIGHT...MAY SEE A BIT MORE FOG THAN PREVIOUS NIGHTS WITH SOME
MVFR VSBYS...BUT THIS WILL LIKELY BE AT THE TYPICALLY PRONE
AIRPORTS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZES LIKELY SHIFT
SOUTH BY LATE DAY.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY AND FRIDAY...MODERATE CONFIDENCE. IFR IN S COASTAL FOG
EARLY. ISOLATED SHOWERS/TSTMS WITH LOCAL IFR IN AFTERNOON.
SATURDAY...MODERATE CONFIDENCE. IFR IN S COASTAL FOG EARLY.
SCATTERED SHOWERS/TSTMS WITH LOCAL IFR IN AFTERNOON/EVENING.
SUNDAY...MODERATE CONFIDENCE. BECOMING VFR BY AFTERNOON.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE...
WINDS AND SEAS REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH
WED NIGHT. HIGH PRES REMAINS OVER THE WATERS THROUGH WED. A LOW
PRES APPROACHES THE WATERS AND WEAKENS WED NIGHT. THERE IS A
CHANCE OF SOME REDUCED VSBYS IN FOG IN SOME SPOTS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY AND FRIDAY...HIGH CONFIDENCE.
WEAK GRADIENT WILL RESULT IN SEA BREEZES ALONG E COAST WITH MORE
OF A SW FLOW ALONG S COAST WHERE 20KT GUSTS POSSIBLE. ISOLATED
THUNDERSTORMS POSSIBLE BOTH DAYS NEAR SHORE. EXPECT AREAS OF
NIGHTTIME AND EARLY MORNING FOG AROUND CAPE COD.
SATURDAY...MODERATE CONFIDENCE.
APPROACHING COLD FRONT WILL BRING INCREASING SW FLOW ON ALL WATERS
AS SEAS SLOWLY BUILD ON S COASTAL WATERS. STAYED BELOW WAVE WATCH
MODEL FORECAST OF 6-8 FT AS THIS MODEL IS TYPICALLY OVERDONE IN SW
FLOW DURING SUMMER...SHOULD BE MORE LIKE 4-5 FT AT MOST AND SCA
WILL PROBABLY BE NEEDED OFFSHORE.
AREAS OF NIGHTTIME AND EARLY MORNING FOG SHOULD PERSIST AROUND
CAPE COD.
SCATTERED THUNDERSTORMS POSSIBLE IN TWO ROUNDS...FIRST EARLY SAT
MORNING /PERHAPS NEAR S COAST?/ AND AGAIN TOWARD EVENING INTO SAT
NIGHT AS COLD FRONT PUSHES THROUGH NEW ENGLAND.
SUNDAY...MODERATE CONFIDENCE.
WINDS SHIFT TO NW AND DIMINISH AS COLD FRONT HEADS OFFSHORE BY
AFTERNOON. SEAS SLOWLY DIMINISH AS WELL BUT SHOULD REMAIN AT 5 OR
6 FT SE OF CAPE COD. SHOWERS/THUNDERSTORMS SHOULD LINGER
INITIALLY ON WATERS SE OF NANTUCKET BUT SHOULD BE WELL OFFSHORE BY
EARLY AFTERNOON.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR CTZ002>004.
MA...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR MAZ002>021-026.
NH...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR NHZ011-012-015.
RI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR RIZ001>007.
MARINE...NONE.
&&
$$
SYNOPSIS...JWD/GAF
NEAR TERM...DOODY
SHORT TERM...GAF
LONG TERM...JWD
AVIATION...DOODY/JWD
MARINE...JWD/GAF
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
850 PM EDT THU JUL 18 2013
.UPDATE...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS THAT THE UPPER RIDGE WHICH
HAS BROUGHT A SIGNIFICANT HEAT WAVE TO MUCH OF THE EASTERN AND
MIDWESTERN PORTIONS OF THE COUNTY IS BEGINNING TO BREAK DOWN AS THE
NORTHERN STREAM AMPLIFIES SOUTHWARD INTO THE GREAT LAKES/OHIO VALLEY
BY THE END OF FRIDAY. AT THE SAME TIME...A WEAK UPPER LOW HAS BEEN
RETROGRADING WESTWARD FROM TH FLORIDA PENINSULA AND IS NOW CENTERED
SOMEWHERE NEAR OR JUST SOUTH OF THE MS DELTA REGION. UPPER LEVEL
SUPPORT SYNOPTIC SUPPORT/CYCLONIC FLOW ASSOCIATED WITH THIS FEATURE
ALONG WITH LOWER LEVEL FOCUS ALONG ITS SURFACE REFLECTION TROUGH
PROVIDED ANOTHER DAY OF NUMEROUS SHOWERS/STORMS AND ABUNDANT CLOUD
COVER FOR MUCH OF THE REGION. IT TOOK SOME TIME FOR THE NATURE COAST
TO GET INTO THE ACTION...ALLOWING THESE ZONES TO SEE THE BEST
HEATING THROUGH THE DAY. HOWEVER...BY EARLY EVENING THE CONVECTION
HAD WORKED FAR ENOUGH NORTH TO GIVE MUCH OF THESE NORTHERN AREAS A
SHOWER OR STORM AS WELL. ATMOSPHERE HAS BEEN WELL "WORKED OVER" BY
NOW...AND ALONG WITH THE LOSS OF ANY RESIDUAL DIURNAL HEATING...THE
RADAR ACTIVITY OVER LAND IS RAPIDLY DECLINING. HAVE LOWERED POPS
QUITE A BIT FOR MOST AREAS INTO THE LATER EVENING AND EARLY MORNING
HOURS.
GOOD MODEL AGREEMENT THAT A RESURGENCE IN NOCTURNAL CONVECTIVE
ACTIVITY WILL OCCUR LATE TONIGHT OVER THE EASTERN GULF OF
MEXICO...WITH SOME OF THESE SHOWERS MAKING THEIR MAY BACK TOWARD
THE COAST. VERY LATE TONIGHT INTO EARLY FRIDAY MORNING...GUIDANCE IS
SHOWING THE MOST FAVORABLE AREAS FOR SCT SHOWERS/STORMS MOVING
ONSHORE TO BE FROM PINELLAS COUNTY NORTHWARD. THIS IS THE REGION
THAT WILL SEE THE HIGHEST RAIN CHANCES IN THE FORECAST DURING FRIDAY
MORNING. THEREAFTER...OVERALL LACK OF ANY SUPPRESSION AND PLENTY OF
DEEP LAYER MOISTURE SHOULD GIVE MOST AREAS A GOOD SHOT AT
SHOWERS/STORMS FOR THE AFTERNOON HOURS. LAPSE RATES ON FRIDAY WILL
BE SIMILAR TO THURSDAY IN THE MOIST ADIABATIC RANGE. THESE PROFILES
IN THE SUMMER HERE CAN LEAD TO SOME LOCALLY HEAVY RAINFALL...BUT
GENERALLY MEAN THE OVERALL THUNDERSTORMS WILL BE LESS INTENSE. WITH
ALL THE DEEP LAYER MOISTURE...THE CHANCES OF MUCH SUN DURING THE
AFTERNOON HOURS DOES NOT LOOK GOOD EITHER. ABUNDANT SHOWERS WILL
LIKELY PRODUCE A DECENT CIRRUS CANOPY FOR AT LEAST THE SECOND HALF
OF THE DAY AND WILL KEEP THE FORECAST MOSTLY CLOUDY.
A MORE TYPICAL SUMMER PATTERN SHOULD RE-VISIT THE REGION FOR THE
UPCOMING WEEKEND WITH PARTLY SUNNY SKIES AND A MORE TYPICAL
DISTRIBUTION OF DIURNAL SHOWERS AND STORMS. ENJOY THE REMAINDER OF
YOUR THURSDAY EVENING.
&&
.AVIATION...
SHRA/TSRA HAVE JUST ABOUT ENDED BUT WILL HAVE VCSH AT TPA/PIE UNTIL
19/03Z. HOWEVER EXPECT SOME LATE NIGHT SHRA ON THE GULF THAT MAY
DRIFT ONSHORE BUT WILL CARRY VCSH ONLY AT SRQ...AFTER 19/06Z. FRI
WILL HAVE SCT-OCNL NMRS SHRA/TSRA AFTER 19/15Z THAT CONTINUE TO THE
END OF THE PERIOD. LIGHT SE WINDS OVERNIGHT BECOME SOUTH AND S-SW
DURING THE DAY.
&&
.MARINE...
WINDS OUT OF THE SOUTH AND SOUTHEAST MAY AT TIMES APPROACH
CAUTIONARY LEVELS THROUGH FRIDAY AFTERNOON OVER THE EASTERN GULF OF
MEXICO AS THE PRESSURE GRADIENT TIGHTENS A BIT BETWEEN THE
SUBTROPICAL RIDGE BUILDING IN FROM THE EAST...AND A SURFACE TROUGH
OVER THE CENTRAL GULF. THE RIDGE AXIS WILL WIN OUT FOR THE UPCOMING
WEEKEND AND KEEP WINDS AND SEAS BELOW HEADLINE CRITERIA DURING
SATURDAY AND SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 89 77 90 / 20 60 30 50
FMY 73 90 74 91 / 30 50 30 50
GIF 73 90 74 91 / 20 60 30 50
SRQ 74 90 75 90 / 40 60 30 50
BKV 71 90 72 91 / 40 60 30 50
SPG 76 90 79 91 / 30 60 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
303 PM EDT WED JUL 17 2013
.DISCUSSION...
CURRENTLY-TONIGHT...DAYTIME HEATING CONVECTION WILL PUSH ACROSS
THE INTERIOR TO THE WEST COAST THROUGH LATE AFTERNOON. WILL CARRY
SMALL POPS ACROSS THE INTERIOR THROUGH EVENING FOR THIS ACTIVITY.
THE LATEST RAP ANALYSIS SHOWS THE CENTER OF UPPER LEVEL LOW
CONTINUING TO PUSH SLOWLY WEST/NORTHWEST OVER THE NORTHEAST GULF.
EXPECT THIS WILL CAUSE AREAS OF DIVERGENCE ALOFT THAT HAVE BEEN
OVER THE ATLANTIC TO GET CLOSER TO THE LOCAL AREA THIS EVENING
AND OVERNIGHT.
ADDITIONALLY A WEAK LOW LEVEL TROUGH SHOULD NUDGE INTO OUR
SOUTHERN AREAS OVERNIGHT. THE COMBINATION OF LOW LEVEL CONVERGENCE
AND UPPER LEVEL DIVERGENCE SHOULD CAUSE CONVECTION TO FLARE UP AND
AFFECT A PORTION OF OUR COAST...MAINLY FROM THE CAPE SOUTHWARD TO
THE TREASURE COAST. A CHANCE FOR LOCALLY HEAVY RAINFALL EXISTS.
WILL CARRY 30 POPS IN BREVARD AND INCREASE TO 50 PERCENT IN MARTIN
FOR THIS EVENING/OVERNIGHT CONVECTION.
PREVIOUS DISCUSSION...
THU-FRI...STRONG RIDGE EXTENDING ACROSS THE CENTRAL TO EASTERN
U.S. WILL BREAK DOWN AS UPPER LEVEL TROUGH BUILDS SOUTHWARD FROM
THE GREAT LAKES REGION. AT THE SFC AN INVERTED TROUGH WILL SHIFT
WESTWARD INTO FLORIDA THURSDAY AND USHER IN A WETTER PATTERN INTO
LATE WEEK. BOTH GFS AND NAM SHOW PW VALUES INCREASING TO ABOVE 2
INCHES WHICH WILL KEEP HIGHER RAIN CHANCES OVER THE REGION. HAVE
INCREASED POPS TO 50-60% THURSDAY AND AROUND 50% FRIDAY. A FEW
SHOWERS EXPECTED EARLY IN THE MORNING WITH INCREASING COVERAGE OF
SHOWERS AND STORMS INTO THE LATE MORNING AND AFTERNOON.
SAT-TUE...UPPER LEVEL TROUGH DIGS FARTHER SOUTH THIS WEEKEND AND
REMAINS ACROSS THE EASTERN CONUS INTO EARLY NEXT WEEK. THIS WILL KEEP
THE AXIS OF THE SUBTROPICAL RIDGE ACROSS SOUTH FLORIDA FOR MUCH OF
THE PERIOD. DEEP MOISTURE AND A MORE PREVALENT LOW TO MID LEVEL W/SW
FLOW WILL FAVOR BEST RAIN CHANCES OVER EAST CENTRAL FLORIDA
ESPECIALLY WITH ANY BOUNDARY INTERACTIONS WHERE THE EAST COAST SEA
BREEZE IS ABLE TO DEVELOP IN THE AFTERNOON. TEMPERATURES WILL REMAIN
NEAR TO SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...
A BIT MORE OF A TYPICAL DIURNAL REGIME WITH SCATTERED SHOWERS AND
ISOLATED STORMS MOSTLY PUSHING ACROSS THE INTERIOR FROM KMCO-KISM
SOUTHWARD. EXPECT A FEW SHOWERS TO MOVE ACROSS AREAS NORTH OF
THIS AND TO THE COAST AROUND KTIX.
FOR COASTAL SITES FROM KMLB-KSUA...THERE SHOULD BE A FLARE UP OF
CONVECTION OVER THE ATLANTIC THIS EVENING OR OVERNIGHT. WHILE IT
IS TOO EARLY TO PUT DETERIORATING CONDITIONS INTO THE TAFS...
EXPECT SOME PORTION OF THIS AREA TO BE AFFECTED WITH PERIODS OF
MVFR-IFR CONDITIONS...WHICH MAY LINGER INTO EARLY THU. EXPECT
CONVECTION DURING DAYTIME HEATING ON THU TO BE FOCUSED ON THE
INTERIOR TERMINALS.
&&
.MARINE...
TONIGHT...WEAK LOW LEVEL TROUGH IS FORECAST TO LIFT NORTH INTO THE
WATERS. THIS WILL START TO EASE THE PRESSURE GRADIENT AND VEER
WINDS MORE TO THE SOUTHEAST. MORE IMPORTANTLY SHOULD BE A
POTENTIAL FOR A FLARE UP OF CONVECTION OVER THE ATLANTIC WATERS
WHICH MAY LINGER MUCH OF THE NIGHT ESPECIALLY SOUTH OF CANAVERAL.
THU-SUN...A WEAK INVERTED TROUGH IS FORECAST TO PUSH INTO THE GULF
ON THU WITH THE ATLANTIC SURFACE RIDGE NOSING BACK TOWARDS THE
FLORIDA PENINSULA. THIS WILL CAUSE A SOUTHEAST WIND FLOW ON THU TO
BECOME MOSTLY SOUTHERLY ON FRI AND CONTINUE OVER THE WEEKEND.
SPEEDS SHOULD BE LESS THAN 15 KNOTS. QUITE HIGH MOISTURE WILL LEAD
TO A GREATER THAN NORMAL CHANCE OF ATLANTIC SHOWERS/STORMS THROUGH
THE PERIOD. DAYTIME HEATING STORMS OVER THE MAINLAND SHOULD START
TO PUSH TO THE COAST FRI AND THEN ACROSS THE COAST THIS WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 73 87 74 90 / 20 40 30 50
MCO 73 90 74 92 / 20 50 30 50
MLB 74 87 74 90 / 20 50 30 50
VRB 71 88 73 89 / 30 60 30 50
LEE 73 91 75 92 / 20 50 30 50
SFB 74 91 75 92 / 20 40 30 50
ORL 74 91 75 92 / 20 50 30 50
FPR 71 87 72 89 / 30 60 30 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...LASCODY
IMPACT WEATHER/RADAR...MOSES/CRISTALDI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
933 AM EDT WED JUL 17 2013
.DISCUSSION...
TODAY/TONIGHT...THE LATEST RAP ANALYSIS SHOWS THE CENTER OF AN UPPER
LEVEL LOW JUST WEST OF TAMPA. SEVERAL CLUSTERS OF CONVECTION WERE
OCCURRING ON THE EAST SIDE OF THIS CIRCULATION FROM THE KEYS AND
FLORIDA STRAITS TO THE NORTHERN BAHAMAS IN DIFFLUENT/DIVERGENT
FLOW. A LOW LEVEL TROUGH PRODUCING CONVERGENCE WAS ALSO ALIGNED
FROM THE KEYS TO NEAR GRAND BAHAMA. GPS PRECIPITABLE WATER DATA
SHOWED NEAR 2 INCHES IN THE SOUTH AND 1.6 INCHES IN OUR FAR NORTH.
A GRADUAL WEST/NORTHWEST MOTION OF THE UPPER LOW AND LOW LEVEL
TROUGH WILL NUDGE DEEP MOISTURE SLOWLY NORTHWARD ACROSS THE
PENINSULA. HIGHEST POPS SHOULD AGAIN BE ALONG THE TREASURE COAST
AND OKEECHOBEE. EVEN THOUGH THERE WILL BE MORE CLOUDINESS THERE
TODAY...WILL HAVE TO WATCH FOR SOME POSSIBLE HEAVY RAINFALL. 15 TO
20 KNOT LOW LEVEL FLOW IN THE PRESENCE OF UPPER LEVEL DIVERGENCE
COULD LEAD TO TRAINING OF CELLS.
CENTRAL SECTIONS WILL HAVE SOME MORNING HEATING AND EXPECT
BOUNDARIES TO GENERATE A FEW ROUNDS OF SHOWERS AND ISOLATED STORMS.
IT REMAINS COOL ALOFT (MINUS 9 DEGREES CELSIUS AT 500MB) SO A FEW
STORMS WITH GUSTY WINDS TO 40 MPH SHOULD OCCUR AGAIN. THE DRIER AIR
ACROSS THE NORTH WILL HOLD ON AT LEAST ONE MORE DAY AND KEEP RAIN
CHANCES LOW.
NO CHANGES PLANNED TO CURRENT FORECAST.
&&
.AVIATION...
DAYTIME HEATING WILL SPARK AN INCREASE IN SHOWERS/STORMS ESPECIALLY
KTIX-KMCO SOUTHWARD. MORE THAN ONE ROUND OF MVFR-IFR CONDITIONS WITH
GUSTY WINDS TO AROUND 30 KNOTS WILL BE POSSIBLE. THE ACTIVITY MAY
PERSIST INTO THE EVENING AS UPPER LEVEL DIVERGENCE SETS UP FROM
ABOUT CANAVERAL TO OKEECHOBEE.
&&
.MARINE...
TODAY/TONIGHT...STILL POOR CONDITIONS FOR SMALL CRAFT AS EASTERLY
WINDS REMAIN 10-15 KNOTS WITH A DOMINANT SHORTER WAVE PERIOD AROUND
6 SECONDS. SHOWERS/STORMS ALSO EXPECTED TO INCREASE AS THE
AFTERNOON PROGRESSES WITH TORRENTIAL DOWNPOURS AND GUSTY WINDS 30-35
KNOTS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...LASCODY
IMPACT WEATHER...MOSES
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
337 PM EDT WED JUL 17 2013
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS MAIN EASTERN WAVE MOVING INTO NE GA AT
THE MOMENT. THE CURRENT RADAR LOP SHOWS SHOWERS AND ISOLATED
THUNDERSTORMS POPPING UP ACROSS NE GA WHICH IS DEFINITELY BEING GENERATED
BY THIS WAVE. THE MAIN ENERGY FROM THIS WAVE IS EXPECTED TO STAY
ACROSS NORTH GA BUT BOTH OUR LOCAL WRF AND THE HRRR SHOW A BIT MORE
DIURNALLY DRIVEN POP UP SHRA/TSRA ACROSS THE STATE THROUGH 02-04Z
TONIGHT. THE SURFACE TO UPPER LEVEL RIDGE KEEPS OUR AREA IN MOIST
EASTERLY FLOW THROUGH THE SHORT TERM. THE MODELS ARE SHOWING ANOTHER
WEAKER WAVE MOVING ACROSS THE AREA THU IN THIS EASTERLY FLOW. WITH
THIS IN MIND SHOULD SEE ANOTHER DIURNALLY DRIVEN CONVECTIVE DAY THU.
THERE IS VERY LITTLE SHEAR IN THIS ATMOSPHERE BUT THE CAPES AND LIS
BOTH PEAK BETWEEN 18Z AND 00Z THIS AFTERNOON AND THURSDAY. TODAY
SHOULD BE THE WARMEST DAY THIS WEEK WITH RISING THICKNESSES TODAY
HOWEVER PRECIP/CLOUDS MAY OFFSET THE WARMING A LITTLE. H5 HEIGHTS
WILL BE DROPPING THURSDAY YIELDING A SLIGHTLY COOLER TEMPS. STAYING
CLOSE TO CURRENT FORECAST TEMPS AS THEY STILL LOOKS GOOD.
01
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO SIG CHANGES TO THE EXTENDED. ONLY CHANGE WERE TO THE POPS ON
SUNDAY WHERE OUR NEIGHBORS AND GUIDANCE SUGGESTS A LIKELY CHANCE
OF POPS. DECIDED TO GO WITH THAT FOR SUNDAY AFTERNOON. OTHERWISE
UPDATED THE DEWPOINTS...WINDS AND TEMPERATURES WITH NEW GUIDANCE.
HAVE ATTACHED PREVIOUS DISCUSSION FOR BREVITY.
ARG
&&
.PREV DISCUSSION... /ISSUED 730 AM EDT WED JUL 17 2013/
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED AT 355 AM EDT WED JUL 17 2013/
A TRANSITION TAKES PLACE THIS PERIOD FROM EAST FLOW ALOFT TO
WESTERLY FLOW WITH A UPPER TROUGH DEVELOPING OVER THE EASTERN
STATES. GFS AND EUROPEAN ARE SIMILAR WITH THIS CHANGE UNTIL THE
MONDAY TO WEDNESDAY TIME FRAME WHEN THE EUROPEAN MOVES THE TROUGH
TO THE WESTERN ATLANTIC AND THE GFS KEEPS THE UPPER TROUGH OVER THE
OH/TN VALLEYS AS A STRONGER UPPER SHORT WAVE MOVES OVER THE MID U.S.
PLENTY OF MOISTURE AND INSTABILITY THIS PERIOD FOR AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST AREAS...TENDING TO
MAXIMIZE IN THE AFTERNOON AND EVENING HOURS. DEEPER MOISTURE MOVES
ACROSS THE AREA WITH THE INITIAL ONSET OF THE UPPER TROUGH
SUNDAY/MONDAY AS A FRONT BECOMES STATIONARY JUST N OF GA AND A
SURFACE TROUGH SETS UP FROM THE CAROLINAS INTO GA. TEMPERATURES
GENERALLY CLOSE TO NORMAL EXCEPT HIGH TEMPERATURES WILL RUN
SLIGHTLY BELOW NORMAL FROM SATURDAY ON.
BDL
AVIATION...
18Z UPDATE...
SOME FEW TO SCT CLOUDS FORMING ACROSS THE AREA THIS AFTERNOON.
CLOUDS MAINLY IN THE 4000-6000FT RANGE AND NOT EXPECTING THINGS TO
GO BKN OR OVC. SHRA/TSRA HAVE BEGUN POPPING UP AND SHOULD SEE MORE
COVERAGE OVER THE NEXT FEW HOURS. THESE SHOWER AND THUNDERSTORMS
SHOULD STA OUT OF THE TAF SITES TILL 21Z. THIS CONVECTIVE ACTIVITY
IS DIURNALLY DRIVEN SO SHOULD SEE SHRA/TSRA DIMINISH BY 02-04Z.
WINDS ARE TURNING TO THE EAST AND SHOULD STAY THERE THROUGH THE
TAF PERIOD. NO RESTRICTIONS TO VSBYS EXPECTED EXCEPT IN AND AROUND
TSRA DEVELOPMENT.
//ATL CONFIDENCE...18Z UPDATE...
CONFIDENCE HIGH ON ALL ELEMENTS.
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 92 71 90 / 40 30 30 40
ATLANTA 74 91 73 88 / 40 30 30 50
BLAIRSVILLE 69 88 68 84 / 40 50 30 50
CARTERSVILLE 70 91 71 89 / 40 40 30 50
COLUMBUS 73 94 73 90 / 20 30 30 50
GAINESVILLE 73 90 73 88 / 40 40 30 50
MACON 71 92 71 90 / 30 30 20 40
ROME 71 92 71 90 / 40 40 30 50
PEACHTREE CITY 71 91 70 89 / 40 30 30 50
VIDALIA 72 93 72 89 / 20 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....ARG
AVIATION...01
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1241 AM CDT WED JUL 17 2013
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1201 PM CDT TUE JUL 16 2013
AT 12Z TUESDAY A 500MB LOW WAS LOCATED OVER EASTERN NEW MEXICO
AND A 500MB HIGH WAS LOCATED OVER THE OHIO VALLEY. ACROSS THE
SOUTHERN AND CENTRAL PLAINS A SOUTHEAST FLOW IN THE 850MB TO 500MB
LEVEL WAS DRAWING HIGHER DEWPOINTS INTO WESTERN KANSAS. ONE UPPER
LEVEL DISTURBANCE ROTATING AROUND THIS UPPER LOW WAS LOCATED
ACROSS THE PANHANDLE OF TEXAS AND WESTERN OKLAHOMA AS OF 12Z
TUESDAY WITH ANOTHER DISTURBANCE LOCATED NEAR THE BASED OF THIS
UPPER LOW ACROSS WESTERN TEXAS. WATER VAPOR LOOP AS OF 15Z
INDICATED THIS UPPER LOW WAS MOVING SLOWLY WESTWARD AS THE
PANHANDLE UPPER LEVEL WAVE APPROACHES SOUTHWEST KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 159 PM CDT TUE JUL 16 2013
RAP AND WATER VAPOR LOOP INDICATING AN UPPER LEVEL DISTURBANCE
WAS MOVING NORTHWEST ACROSS THE PANHANDLE OF TEXAS AS OF 19Z WITH
RADAR TRENDS INDICATING PRECIPITATION INCREASING IN AREA COVER
AHEAD OF THIS DISTURBANCE ACROSS PORTIONS OF SOUTHWEST KANSAS. NAM
AND RAP WERE IN DECENT AGREEMENT IN MOVING THIS UPPER WAVE ACROSS
SOUTHWEST KANSAS INTO SOUTHEAST COLORADO EARLY TONIGHT. GIVEN THE
MOISTURE FORECAST ACROSS SOUTHWEST KANSAS IN THE 850MB TO 500MB
AHEAD OF THIS UPPER SYSTEM WILL RETAIN AT LEAST A CHANCE FOR
SHOWERS ACROSS SOUTHWEST KANSAS AT AROUND 03Z AND THEN TAPER
PRECIPITATION OFF FROM NORTHEAST TO SOUTHWEST.
AFTER MIDNIGHT SUBSIDENCE APPEARS TO DEVELOP ACROSS WESTERN KANSAS
AS THE UPPER LEVEL DISTURBANCE MOVES INTO SOUTHERN COLORADO.
CLEARING SKIES MAY BRIEFLY DEVELOP AFTER MIDNIGHT, HOWEVER SOME
EARLY MORNING STATUS AND/OR FOG WILL BE POSSIBLE AROUND DAYBREAK
GIVEN THE SHALLOW LAYER OF LOW LEVEL MOISTURE FORECAST BY THE 12Z
NAM. BASED ONE THE EXPECTED DEWPOINTS OVERNIGHT THE PREVIOUS
FORECAST WITH LOWS RANGING FROM 60 TO NEAR 65 DEGREES STILL LOOKS
ON TRACK.
ON WEDNESDAY A TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE LEE
OF THE ROCKIES. BASED ON EXPECTED SKY COVER AND 00Z 850MB
TEMPERATURES RANGING FROM AROUND 20 IN SOUTH CENTRAL KANSAS TO THE
MID 20S NEAR THE COLORADO BORDER HAVE DECIDED TO TREND TOWARDS THE
SLIGHTLY COOLER ECMWF GUIDANCE FOR HIGHS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 333 PM CDT TUE JUL 16 2013
WEDNESDAY NIGHT:
LEE TROUGHING WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY MORNING.
THE UPPER LEVEL DISTURBANCE MENTIONED IN THE SYNOPSIS/SHORT TERM PERIOD
WILL CONTINUE TO DRIFT WELL AWAY FROM THE REGION BY THURSDAY MORNING.
STILL, THERE WILL BE "COOLER" LOW TO MID LEVEL TEMPERATURES ASSOCIATED
WITH THE PRESSURE PERTURBATION LINGERING ACROSS THE REGION. CONSIDERING
THIS AND THE WARM BIAS SHOWN VIA BOISE VERIFICATION...HAVE GONE WITH
COOLER MOS GUIDANCE FOR MINIMUMS INTO THURSDAY MORNING...60S DEG F.
THURSDAY:
ON THURSDAY, THE AFOREMENTIONED LEE SURFACE TROUGH WILL CONTINUE TO
DEEPEN AHEAD OF A TRAVERSING SHORTWAVE TROF ACROSS THE NORTHERN PLAINS.
THIS WILL ALLOW FOR A CONTINUED WARM AIR ADVECTION REGIME THROUGH THE
DAY. HAVE GONE WITH COOLER ECMWF RAW OUTPUT FOR MAXIMUMS - MID 90S DEG
F NORTHEAST TO AROUND 90 DEG F SOUTHWEST. NO PRECIPITATION IS EXPECTED
THROUGH THE DAY WITH PRECIPITATION PROBABILITY PERCENTAGE POINTS AOB
10 PERCENT AS THE AFOREMENTIONED SYNOPTIC SYSTEM IS WELL TO THE NORTH.
FRIDAY AND BEYOND:
A MODERATION OF TEMPERATURES IS EXPECTED WITH MAXIMUMS IN THE 90S DEG
F AND LOWS IN THE 60S AND 70S DEG F AS LEE TROUGHING CONTINUES AHEAD
OF AN APPROACHING COLD FRONT. THIS FRONT SHOULD BE IN THE REGION (PER
ECMWF) SOMETIME LATE FRIDAY NIGHT AND INTO SATURDAY. CONVECTION WILL
BE POSSIBLE ALONG THIS DENSITY GRADIENT THROUGH THE WEEKEND. THE 12Z
ECMWF SOLUTION HAS TRENDED DRIER THAN COMPARED TO THE 00Z ECMWF SOLUTION.
THE GFS, AS PER USUAL, IS WETTER AND COOLER THAN COMPARED TO THE EC.
DUE TO THE UNCERTAINTY, WILL GO WITH THE ALLBLEND SOLUTION FOR NOW.
THIS MODEL - OF COURSE - APPLIES A WEIGHTING FUNCTION TO BOTH SOLUTIONS
PLUS THE PREVIOUS NDFD GRIDS. BEYOND THIS, 500 HPA RIDGING IS INDICATED
BY BOTH MODELS BY EARLY TO MID WEEK OF NEXT WEEK, WHICH FAVORS A DRY
FORECAST AND HOT TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1241 AM CDT WED JUL 17 2013
VFR CIGS AND VSBYS AT THE BEGINNING OF THIS TAF PERIOD ARE
EXPECTED TO DETERIORATE TO MVFR/IFR FROM AROUND 10Z-15Z AS LOW
LEVEL MOISTURE REMAINS ACROSS WESTERN KANSAS. THE LOW CIGS WILL
MIX OUT THROUGH THE MORNING HOURS WITH VFR CONDITIONS RETURNING.
THERE COULD BE SOME ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS
DEVELOPING ACROSS SOUTHWEST KANSAS WEDNESDAY AFTERNOON BUT THE
ISOLATED NATURE PRECLUDES MENTIONING IN THE TAFS AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 91 68 94 / 10 0 10 40
GCK 64 90 68 94 / 10 10 10 40
EHA 62 88 66 94 / 10 10 10 40
LBL 64 89 67 94 / 10 10 10 40
HYS 67 94 72 94 / 0 0 10 30
P28 68 91 70 95 / 10 0 10 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1138 PM CDT TUE JUL 16 2013
.DISCUSSION...
06Z TAFS
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS HAVE LARGELY CONFINED THEMSELVES TO THE
OFFSHORE WATERS VERY SIMILAR TO LAST NIGHT. THE MAIN EXCEPTION IS
ACROSS PARTS OF SOUTHEAST TEXAS WHERE A FEW SHOWERS HAVE BEEN
STREAMING ONSHORE OVER THE LAST HOUR. A COUPLE OF STRAY LIGHTNING
STRIKES CANT BE RULED OUT BUT GIVEN THE GENERAL WEAKENING TREND OF
CELLS AS THEY MOVE INLAND OPTED TO JUST INCLUDE VCSH AT BPT
THROUGH THE EARLY MORNING. KEPT OTHER SITES DRY AND VFR THROUGH
THE PERIOD ALTHOUGH A FEW ISOLATED THUNDERSTORMS COULD DEVELOP
DURING THE AFTERNOON HOURS.
&&
66
.PREV DISCUSSION... /ISSUED 1018 PM CDT TUE JUL 16 2013/
UPDATE...
OVERALL FCST IN GOOD SHAPE. RECENT RADAR TRENDS SHOW CONVECTION
OVER LAND HAS DIMINISHED WITH SCT ACTIVITY CONTINUING OVER THE
COASTAL WATERS. MADE SOME MINOR ADJUSTMENTS TO POPS...INCREASING
THEM OVER THE COASTAL WATERS AND IMMEDIATE COASTAL AREAS FOR THIS
EVENING. POPS AFTER MIDNIGHT STILL LOOK ON TRACK AND SEEM TO BE IN
DECENT AGREEMENT WITH RECENT NAM12 AND HRRR RUNS WITH BEST CHANCES
OVER THE WRN HALF OF THE COASTAL WATERS. TWEAKED HOURLY
TEMPS...DEWPOINTS AND WINDS TO REFLECT RECENT OBSERVATIONAL
TRENDS...BUT NO SIGNIFICANT CHANGES TO REMAINDER OF FCST. 24
PREV DISCUSSION... /ISSUED 641 PM CDT TUE JUL 16 2013/
DISCUSSION...
00Z
AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS MOVING AROUND THE PERIPHERY OF
A DEVELOPING HIGH CONTINUE ACROSS THE AREA THIS EVENING. EXPECT
THE ACTIVITY TO CONTINUE FOR THE NEXT COUPLE OF HOURS BEFORE
WANING WITH THE SETTING SUN. A FEW THUNDERSTORMS WILL LIKELY CONTINUE
OFFSHORE OVERNIGHT BUT THEY SHOULD NOT IMPACT TERMINALS. AS THE
HIGH CONTINUES TO BUILD IN...STORMS BE PUSHED FURTHER SOUTHWEST.
THEREFORE EXPECT ONLY ISOLATED THUNDERSTORMS WEDNESDAY AFTERNOON.
66
PREV DISCUSSION... /ISSUED 327 PM CDT TUE JUL 16 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS...MORE SCATTERED THAN NUMEROUS IN NATURE
SO FAR...MOVING ACROSS THE FORECAST AREA FROM EAST TO WEST.
SCATTERED ACTIVITY WILL CONTINUE THROUGH EARLY EVENING
HOURS...THEN DIMINISH WITH THE LOSS OF DAYTIME HEATING.
UPPER LEVEL LOW MOVING INTO NEW MEXICO WILL CONTINUE TO MOVE TO
THE WEST WITH UPPER LEVEL RIDGING MOVING IN OVER THE FORECAST AREA
TO TAKE ITS PLACE. THIS SHOULD HELP CUT OFF THE DEEP MOISTURE
FETCH OVER THE FORECAST AREA. THEREFORE...RAIN CHANCES WILL BE
DECREASING OVER THE NEXT COUPLE OF DAYS. EXPECTED SCATTERED
ACTIVITY OVER IN SOUTHEAST TEXAS AND EXTREME WESTERN LOUISIANA ON
WEDNESDAY WITH ISOLATED ELSEWHERE...THEN ISOLATED POPS EVERYWHERE
ON THURSDAY.
THE MID/UPPER LEVEL RIDGE WILL BEGIN TO BREAK DOWN AT THE END OF
THE WEEK INTO THE WEEKEND...WITH THE NEXT WEAK UPPER LEVEL LOW
RETROGRADING INTO THE REGION. THEREFORE...RAIN CHANCES WILL AGAIN
INCREASE TO SCATTERED POPS...WITH NEAR CLIMO TEMPERATURES FROM
FRIDAY THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
RUA
MARINE...
OCCASIONAL WINDS BETWEEN 15 AND 20 KNOTS OCCURRING OVER THE COASTAL
WATERS THIS AFTERNOON. BRIEF PERIODS OF NEAR 20 KNOT WINDS WILL
CONTINUE THROUGH THE EVENING HOURS AS A BIT OF A TIGHTER GRADIENT
AS RIDGE BEGINS TO BUILD IN FROM THE EAST. SO WILL KEEP SMALL
CRAFT EXERCISE CAUTION WORDING THROUGH ABOUT MIDNIGHT.
A LIGHT TO MODERATE EAST TO SOUTHEAST WIND FLOW WILL THEN PREVAIL
THROUGH THE REMAINDER OF THE WEEK...AS COASTAL WATERS REMAIN ON
THE PERIPHERY OF A SURFACE RIDGE LOCATED OVER THE EASTERN U.S.
RUA
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 89 75 91 74 92 / 60 20 30 20 20
KBPT 88 75 90 75 92 / 60 30 40 20 20
KAEX 90 72 93 73 94 / 60 20 20 20 20
KLFT 88 74 91 74 92 / 60 20 20 20 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
645 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLOWLY CROSS NORTHERN MAINE TONIGHT...
PRODUCING A TREAT FOR SHOWERS AND THUNDERSTORMS. THE FRONT WILL
PUSH BACK TO THE NORTH ON THURSDAY...MAKING FOR A RETURN TO HOT
AND HUMID WEATHER ON FRIDAY. A COLD FRONT WILL DROP SOUTH FROM
CANADA FRIDAY NIGHT AND WILL CROSS THE REGION ON
SATURDAY...POSSIBLY SETTING OFF A ROUND OF STRONG TO SEVERE
THUNDERSTORMS. COOLER AND LESS HUMID HIGH PRESSURE BUILDS IN ON
SUNDAY AND LINGERS INTO EARLY NEXT WEEK...BEFORE THINGS START
SHOW SIGNS OF WARMING UP AGAIN.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WILL UPDATE TO SLOW DOWN ONSET OF SHOWERS AND THUNDERSTORMS THIS
EVENING PER LATEST RADAR MOSAIC LOOP. STILL EXPECTING CONVECTIVE
ACTIVITY TO ARRIVE THROUGH THE COURSE OF THE EVENING HOURS...
LIKELY HOLDING OFF UNTIL LATE EVENING ALONG THE COAST. ANY OTHER
CHANGES VERY MINIMAL AT THIS TIME.
ZONES UPDATED TO ADD THE SEVERE THUNDERSTORM WATCH THROUGH
MIDNIGHT TONIGHT. ALREADY HAVE POSSIBLE SEVERE THUNDERSTORMS IN
THE FORECAST FOR THIS EVENING.
SHOWERS AND THUNDERSTORMS DEVELOPING OVER ONTARIO WILL MOVE
SOUTHEAST AND INTO NORTHERN NEW ENGLAND TONIGHT. THIS ACTIVITY
WILL BE PRIMARILY DRIVEN BY A SHORTWAVE TROUGH AND SURFACE COLD
FRONT INTERACTING WITH A VERY WARM/MOIST PRE-FRONTAL ENVIRONMENT.
HRRR MODEL SEEMS TO BE HANDLING THE FORECAST VERY WELL TODAY AND
THIS WAS USED EXTENSIVELY IN THE NEAR TERM FORECAST FOR TONIGHT.
AS COORDINATED WITH THE STORM PREDICTION CENTER... IT APPEARS THAT
INITIALLY ISOLATED CONVECTIVE ACTIVITY OVER CANADA AND UPSTATE NEW
YORK WILL LIKELY EVOLVE INTO A SQUALL LINE AND MOVE SOUTHEAST
THROUGH VERMONT AND NEW HAMPSHIRE AND INTO MAINE. HRRR MODEL SEEMS
TO BE SHOWING THE SIGNS OF AN MESOSCALE CONVECTIVE SYSTEM WITH
TRAILING STRATIFORM RAIN REGION BEHIND IT ARRIVING IN NEW
HAMPSHIRE AROUND 7 TO 8 PM AND HOLDING TOGETHER ALL THE WAY TO THE
COAST BY MIDNIGHT. DAMAGING WINDS WILL BE THE BIGGEST THREAT WITH
THIS SCENARIO TONIGHT... ALTHOUGH VERY MOIST ENVIRONMENT WILL
ALLOW FOR EFFICIENT RAINFALL PRODUCTION. WIDESPREAD RAINFALL OF
OVER ONE INCH ARE POSSIBLE WITH THE LEADING CONVECTIVE BAND AND
TRAILING RAIN REGION.
STORMS SHOULD MOVE OFF THE COAST AROUND MIDNIGHT... WITH CLEARING
BEHIND IT. COULD SEE SOME FOG ESPECIALLY IF RAIN IS WIDESPREAD.
HUMIDITY WILL KEEP TEMPERATURES IN THE UPPER 60S AND LOW 70S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD FRONT / OUTFLOW FROM OVERNIGHT CONVECTION WILL STALL AND WASH
OUT OFFSHORE ON THURSDAY. MAY SEE A RETURN FLOW OF WARM/MOIST AIR
INTO THE AREA WITH TEMPERATURES WARMING INTO THE UPPER 80S AND LOW
90S. DEW POINTS NEAR 70 WILL ALLOW HEAT INDEX VALUES TO RISE INTO
THE UPPER 90S. DO NOT ANTICIPATE NEEDING A HEAT ADVISORY FOR
THURSDAY AS THERE WILL NOT BE A LARGE AREA OF EXTENDED HEAT INDEX
READINGS ABOVE 100. IF HIGHER DEW POINTS OR HIGHER TEMPERATURES
ARE ACHIEVED... THEN THIS CRITERIA COULD BE MET. CONDITIONS WILL
BE CLOSE TO ADVISORY CRITERIA... BUT CONSIDERING THAT THE HOT AND
HUMID WEATHER HAS BEEN AROUND FOR SEVERAL WEEKS THIS SUMMER... DID
NOT THINK A MARGINAL ADVISORY WAS NEEDED AS THE AWARENESS OF THE
HOT AND HUMID WEATHER IS ALREADY HIGH.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON
TOMORROW... PRIMARILY OVER THE SOUTHWESTERN HALF OF THE AREA WHERE
BETTER INSTABILITY EXISTS. A SHORTWAVE TROUGH WILL ALSO ADD LIFT
IN THIS AREA TO INCREASE THE CHANCE OF CONVECTION. ALTHOUGH WE
CANNOT RULE OUT THE THREAT FOR DAMAGING WINDS WITH ANY STORMS THAT
FORM... THE THREAT DOES NOT APPEAR WIDESPREAD.
EXPECT SHOWERS AND THUNDERSTORMS TO DISSIPATE THURSDAY EVENING.
ANOTHER HUMID NIGHT WILL KEEP TEMPERATURES IN THE UPPER 60S AND
LOW 70S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
500 MB HEIGHTS RISE ON FRIDAY AS RIDGING BUILDS IN BRIEFLY...AND
850 TEMPS APPROACH 20 C. EXPECTING THIS BE ONE OF THE MORE HOT AND
HUMID DAYS WE HAVE SEEN THIS SUMMER...AND HEAT INDEX VALUES WILL
LIKELY REACH 100 IN PARTS OF THE SOUTHERN ZONES...AND A HEAT
ADVISORY MAY BE NEEDED THERE. CANNOT RULE OUT A FEW AIR MASS
THUNDERSTORMS...BUT BETTER CHANCE WILL BE IN NORTHERN
ZONES...WHERE STRONGER WINDS ALOFT...AND APPROACHING COLD FRONT
WILL CREATE BETTER DYNAMICS...AND COULD PRODUCE SOME STRONGER
STORMS. LOOK FOR A WARM AND UNCOMFORTABLE NIGHT FRIDAY NIGHT AS
HUMIDITIES REMAIN HIGH AND INCREASED SW FLOW PREVENTS MIN FROM
DROPPING OFF MUCH. COLD FRONT WILL APPROACH NORTHERN ZONES LATE
FRIDAY NIGHT...AND THE THREAT FOR THUNDERSTORMS WILL INCREASE
TOWARD DAYBREAK...AND SHIFT SOUTHWARD TOWARD THROUGH THE DAY.
GIVEN THE GREAT SURFACE INSTABILITY AND THE STRONG MID-UPPER LEVEL
WINDS DROPPING SOUTHWARD AHEAD OF THE FRONT SATURDAY...THE THREAT
FOR SEVERE CONVECTION REMAINS A CONCERN ON SATURDAY...AND THIS
COULD LINGER INTO THE EVENING.
THE FRONT IS EXPECTED TO CLEAR THE COAST LATE SATURDAY NIGHT OR
EARLY SUNDAY...WITH CLEARING AND NOTICEABLY COOLER AND LESS
HUMID CONDITIONS. THE HIGH THAT BUILDS IN BEHIND THE FRONT WILL
LINGER INTO TUESDAY...WITH TEMPS CLOSE TO OR A LITTLE BELOW NORMAL
DURING THIS PERIOD. AN INCREASE IN HUMIDITY AND TEMPS IS POSSIBLE
BY MID-WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
SHORT TERM /THROUGH THURSDAY NIGHT/...SCATTERED WITH POSSIBLY MORE
NUMEROUS SHOWERS AND THUNDERSTORMS MOVE THROUGH OVERNIGHT WITH
POSSIBLE IFR CIG/VSBY...REACHING NW AREAS FIRST BY 00Z THEN ALONG
THE COAST LAST...MOST LIKELY AFTER 02Z. SHOWERS AND THUNDERSTORMS
END FROM NW TO SE FROM ROUGHLY 04Z TO 06Z. POSSIBLE SEVERE WX WITH
THUNDERSTORMS WITH A SEVERE THUNDERSTORM WATCH IN EFFECT THROUGH
MIDNIGHT ACROSS THE MOUNTAINS AND FOOTHILLS OF WESTERN MAINE AND
ALL OF NEW HAMPSHIRE EXCEPT SOUTHEAST PORTIONS. VALLEY FOG WITH
POSSIBLE IFR/LIFR CIG/VSBY FORMS OVERNIGHT MAINLY WHERE RAIN HAS
FALLEN AND IN MORE FAVORABLE LOCATIONS. VFR THURSDAY AND THURSDAY
NIGHT...EXCEPT LOWER IN SCATTERED AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN...PATCHY FOG POSSIBLE THURSDAY NIGHT.
LONG TERM...MAINLY VFR FRIDAY AND FRIDAY NIGHT...WITH FLIGHT
RESTRICTIONS IS CONVECTION EXPECTED ON SATURDAY INTO SATURDAY
EVENING. VFR RETURNS SUNDAY AND MONDAY.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...WILL UPDATE PER
LATEST BUOY OBSERVATIONS. A FEW GUSTS UP TO 25 KT AT THIS TIME
WILL CONTINUE THROUGH THE EVENING HOURS BUT WON`T BE FREQUENT
ENOUGH TO WARRANT AN SCA. WINDS DROP OFF OVERNIGHT. WILL HOLD SEAS
BELOW 5 FEET OVERNIGHT AS THEY TRY TO BUILD THIS EVENING BUT
SLACKEN OFF OVERNIGHT AS WINDS LET UP. WINDS AND SEAS STAY BELOW
SCA LEVELS THURSDAY AND THURSDAY NIGHT.
LONG TERM...SW FLOW INCREASES AHEAD OF A COLD FRONT FRIDAY NIGHT
INTO SATURDAY WITH SEAS IN EXCESS AROUND 5 FT...AND WINDS APPROACHING
SCA LEVELS. WINDS WILL SHIFT TO NW SATURDAY NIGHT AND DIMINISH.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
424 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLOWLY CROSS NORTHERN MAINE TONIGHT...
PRODUCING A TREAT FOR SHOWERS AND THUNDERSTORMS. THE FRONT WILL
PUSH BACK TO THE NORTH ON THURSDAY...MAKING FOR A RETURN TO HOT
AND HUMID WEATHER ON FRIDAY. A COLD FRONT WILL DROP SOUTH FROM
CANADA FRIDAY NIGHT AND WILL CROSS THE REGION ON
SATURDAY...POSSIBLY SETTING OFF A ROUND OF STRONG TO SEVERE
THUNDERSTORMS. COOLER AND LESS HUMID HIGH PRESSURE BUILDS IN ON
SUNDAY AND LINGERS INTO EARLY NEXT WEEK...BEFORE THINGS START
SHOW SIGNS OF WARMING UP AGAIN.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
ZONES UPDATED TO ADD THE SEVERE THUNDERSTORM WATCH THROUGH
MIDNIGHT TONIGHT. ALREADY HAVE POSSIBLE SEVERE THUNDERSTORMS IN
THE FORECAST FOR THIS EVENING.
SHOWERS AND THUNDERSTORMS DEVELOPING OVER ONTARIO WILL MOVE
SOUTHEAST AND INTO NORTHERN NEW ENGLAND TONIGHT. THIS ACTIVITY
WILL BE PRIMARILY DRIVEN BY A SHORTWAVE TROUGH AND SURFACE COLD
FRONT INTERACTING WITH A VERY WARM/MOIST PRE-FRONTAL ENVIRONMENT.
HRRR MODEL SEEMS TO BE HANDLING THE FORECAST VERY WELL TODAY AND
THIS WAS USED EXTENSIVELY IN THE NEAR TERM FORECAST FOR TONIGHT.
AS COORDINATED WITH THE STORM PREDICTION CENTER... IT APPEARS THAT
INITIALLY ISOLATED CONVECTIVE ACTIVITY OVER CANADA AND UPSTATE NEW
YORK WILL LIKELY EVOLVE INTO A SQUALL LINE AND MOVE SOUTHEAST
THROUGH VERMONT AND NEW HAMPSHIRE AND INTO MAINE. HRRR MODEL SEEMS
TO BE SHOWING THE SIGNS OF AN MESOSCALE CONVECTIVE SYSTEM WITH
TRAILING STRATIFORM RAIN REGION BEHIND IT ARRIVING IN NEW
HAMPSHIRE AROUND 7 TO 8 PM AND HOLDING TOGETHER ALL THE WAY TO THE
COAST BY MIDNIGHT. DAMAGING WINDS WILL BE THE BIGGEST THREAT WITH
THIS SCENARIO TONIGHT... ALTHOUGH VERY MOIST ENVIRONMENT WILL
ALLOW FOR EFFICIENT RAINFALL PRODUCTION. WIDESPREAD RAINFALL OF
OVER ONE INCH ARE POSSIBLE WITH THE LEADING CONVECTIVE BAND AND
TRAILING RAIN REGION.
STORMS SHOULD MOVE OFF THE COAST AROUND MIDNIGHT... WITH CLEARING
BEHIND IT. COULD SEE SOME FOG ESPECIALLY IF RAIN IS WIDESPREAD.
HUMIDITY WILL KEEP TEMPERATURES IN THE UPPER 60S AND LOW 70S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD FRONT / OUTFLOW FROM OVERNIGHT CONVECTION WILL STALL AND WASH
OUT OFFSHORE ON THURSDAY. MAY SEE A RETURN FLOW OF WARM/MOIST AIR
INTO THE AREA WITH TEMPERATURES WARMING INTO THE UPPER 80S AND LOW
90S. DEW POINTS NEAR 70 WILL ALLOW HEAT INDEX VALUES TO RISE INTO
THE UPPER 90S. DO NOT ANTICIPATE NEEDING A HEAT ADVISORY FOR
THURSDAY AS THERE WILL NOT BE A LARGE AREA OF EXTENDED HEAT INDEX
READINGS ABOVE 100. IF HIGHER DEW POINTS OR HIGHER TEMPERATURES
ARE ACHIEVED... THEN THIS CRITERIA COULD BE MET. CONDITIONS WILL
BE CLOSE TO ADVISORY CRITERIA... BUT CONSIDERING THAT THE HOT AND
HUMID WEATHER HAS BEEN AROUND FOR SEVERAL WEEKS THIS SUMMER... DID
NOT THINK A MARGINAL ADVISORY WAS NEEDED AS THE AWARENESS OF THE
HOT AND HUMID WEATHER IS ALREADY HIGH.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON
TOMORROW... PRIMARILY OVER THE SOUTHWESTERN HALF OF THE AREA WHERE
BETTER INSTABILITY EXISTS. A SHORTWAVE TROUGH WILL ALSO ADD LIFT
IN THIS AREA TO INCREASE THE CHANCE OF CONVECTION. ALTHOUGH WE
CANNOT RULE OUT THE THREAT FOR DAMAGING WINDS WITH ANY STORMS THAT
FORM... THE THREAT DOES NOT APPEAR WIDESPREAD.
EXPECT SHOWERS AND THUNDERSTORMS TO DISSIPATE THURSDAY EVENING.
ANOTHER HUMID NIGHT WILL KEEP TEMPERATURES IN THE UPPER 60S AND
LOW 70S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
500 MB HEIGHTS RISE ON FRIDAY AS RIDGING BUILDS IN BRIEFLY...AND
850 TEMPS APPROACH 20 C. EXPECTING THIS BE ONE OF THE MORE HOT AND
HUMID DAYS WE HAVE SEEN THIS SUMMER...AND HEAT INDEX VALUES WILL
LIKELY REACH 100 IN PARTS OF THE SOUTHERN ZONES...AND A HEAT
ADVISORY MAY BE NEEDED THERE. CANNOT RULE OUT A FEW AIR MASS
THUNDERSTORMS...BUT BETTER CHANCE WILL BE IN NORTHERN
ZONES...WHERE STRONGER WINDS ALOFT...AND APPROACHING COLD FRONT
WILL CREATE BETTER DYNAMICS...AND COULD PRODUCE SOME STRONGER
STORMS. LOOK FOR A WARM AND UNCOMFORTABLE NIGHT FRIDAY NIGHT AS
HUMIDITIES REMAIN HIGH AND INCREASED SW FLOW PREVENTS MIN FROM
DROPPING OFF MUCH. COLD FRONT WILL APPROACH NORTHERN ZONES LATE
FRIDAY NIGHT...AND THE THREAT FOR THUNDERSTORMS WILL INCREASE
TOWARD DAYBREAK...AND SHIFT SOUTHWARD TOWARD THROUGH THE DAY.
GIVEN THE GREAT SURFACE INSTABILITY AND THE STRONG MID-UPPER LEVEL
WINDS DROPPING SOUTHWARD AHEAD OF THE FRONT SATURDAY...THE THREAT
FOR SEVERE CONVECTION REMAINS A CONCERN ON SATURDAY...AND THIS
COULD LINGER INTO THE EVENING.
THE FRONT IS EXPECTED TO CLEAR THE COAST LATE SATURDAY NIGHT OR
EARLY SUNDAY...WITH CLEARING AND NOTICEABLY COOLER AND LESS
HUMID CONDITIONS. THE HIGH THAT BUILDS IN BEHIND THE FRONT WILL
LINGER INTO TUESDAY...WITH TEMPS CLOSE TO OR A LITTLE BELOW NORMAL
DURING THIS PERIOD. AN INCREASE IN HUMIDITY AND TEMPS IS POSSIBLE
BY MID-WEEK.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM...THUNDERSTORMS WILL BE POSSIBLE AROUND 00Z IN WESTERN
NEW HAMPSHIRE... SPREADING SOUTH AND EAST THROUGH AROUND 4 OR 6 Z.
THE GREATER CHANCE OF THUNDER WILL BE IN NORTHWEST NEW HAMPSHIRE.
OTHERWISE VFR CONDITIONS EXPECTED OUTSIDE OF VALLEY FOG IN THE
CONNECTICUT RIVER VALLEY.
LONG TERM...MAINLY VFR FRIDAY AND FRIDAY NIGHT...WITH FLIGHT
RESTRICTIONS IS CONVECTION EXPECTED ON SATURDAY INTO SATURDAY
EVENING. VFR RETURNS SUNDAY AND MONDAY.
&&
.MARINE...
SHORT TERM...LIGHT WINDS WILL KEEP CONDITIONS QUIET OVER THE WATERS.
LONG TERM...SW FLOW INCREASES AHEAD OF A COLD FRONT FRIDAY NIGHT
INTO SATURDAY WITH SEAS IN EXCESS AROUND 5 FT...AND WINDS APPROACHING
SCA LEVELS. WINDS WILL SHIFT TO NW SATURDAY NIGHT AND DIMINISH.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
351 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLOWLY CROSS NORTHERN MAINE TONIGHT...
PRODUCING A TREAT FOR SHOWERS AND THUNDERSTORMS. THE FRONT WILL
PUSH BACK TO THE NORTH ON THURSDAY...MAKING FOR A RETURN TO HOT
AND HUMID WEATHER ON FRIDAY. A COLD FRONT WILL DROP SOUTH FROM
CANADA FRIDAY NIGHT AND WILL CROSS THE REGION ON
SATURDAY...POSSIBLY SETTING OFF A ROUND OF STRONG TO SEVERE
THUNDERSTORMS. COOLER AND LESS HUMID HIGH PRESSURE BUILDS IN ON
SUNDAY AND LINGERS INTO EARLY NEXT WEEK...BEFORE THINGS START SHOW
SIGNS OF WARMING UP AGAIN.
&&
.NEAR TERM /TONIGHT/...
SHOWERS AND THUNDERSTORMS DEVELOPING OVER ONTARIO WILL MOVE
SOUTHEAST AND INTO NORTHERN NEW ENGLAND TONIGHT. THIS ACTIVITY
WILL BE PRIMARILY DRIVEN BY A SHORTWAVE TROUGH AND SURFACE COLD
FRONT INTERACTING WITH A VERY WARM/MOIST PRE-FRONTAL ENVIRONMENT.
HRRR MODEL SEEMS TO BE HANDLING THE FORECAST VERY WELL TODAY AND
THIS WAS USED EXTENSIVELY IN THE NEAR TERM FORECAST FOR TONIGHT.
AS COORDINATED WITH THE STORM PREDICTION CENTER... IT APPEARS THAT
INITIALLY ISOLATED CONVECTIVE ACTIVITY OVER CANADA AND UPSTATE NEW
YORK WILL LIKELY EVOLVE INTO A SQUALL LINE AND MOVE SOUTHEAST
THROUGH VERMONT AND NEW HAMPSHIRE AND INTO MAINE. HRRR MODEL SEEMS
TO BE SHOWING THE SIGNS OF AN MESOSCALE CONVECTIVE SYSTEM WITH
TRAILING STRATIFORM RAIN REGION BEHIND IT ARRIVING IN NEW
HAMPSHIRE AROUND 7 TO 8 PM AND HOLDING TOGETHER ALL THE WAY TO THE
COAST BY MIDNIGHT. DAMAGING WINDS WILL BE THE BIGGEST THREAT WITH
THIS SCENARIO TONIGHT... ALTHOUGH VERY MOIST ENVIRONMENT WILL
ALLOW FOR EFFICIENT RAINFALL PRODUCTION. WIDESPREAD RAINFALL OF
OVER ONE INCH ARE POSSIBLE WITH THE LEADING CONVECTIVE BAND AND
TRAILING RAIN REGION.
STORMS SHOULD MOVE OFF THE COAST AROUND MIDNIGHT... WITH CLEARING
BEHIND IT. COULD SEE SOME FOG ESPECIALLY IF RAIN IS WIDESPREAD.
HUMIDITY WILL KEEP TEMPERATURES IN THE UPPER 60S AND LOW 70S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
COLD FRONT / OUTFLOW FROM OVERNIGHT CONVECTION WILL STALL AND WASH
OUT OFFSHORE ON THURSDAY. MAY SEE A RETURN FLOW OF WARM/MOIST AIR
INTO THE AREA WITH TEMPERATURES WARMING INTO THE UPPER 80S AND LOW
90S. DEW POINTS NEAR 70 WILL ALLOW HEAT INDEX VALUES TO RISE INTO
THE UPPER 90S. DO NOT ANTICIPATE NEEDING A HEAT ADVISORY FOR
THURSDAY AS THERE WILL NOT BE A LARGE AREA OF EXTENDED HEAT INDEX
READINGS ABOVE 100. IF HIGHER DEW POINTS OR HIGHER TEMPERATURES
ARE ACHIEVED... THEN THIS CRITERIA COULD BE MET. CONDITIONS WILL
BE CLOSE TO ADVISORY CRITERIA... BUT CONSIDERING THAT THE HOT AND
HUMID WEATHER HAS BEEN AROUND FOR SEVERAL WEEKS THIS SUMMER... DID
NOT THINK A MARGINAL ADVISORY WAS NEEDED AS THE AWARENESS OF THE
HOT AND HUMID WEATHER IS ALREADY HIGH.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON
TOMORROW... PRIMARILY OVER THE SOUTHWESTERN HALF OF THE AREA WHERE
BETTER INSTABILITY EXISTS. A SHORTWAVE TROUGH WILL ALSO ADD LIFT
IN THIS AREA TO INCREASE THE CHANCE OF CONVECTION. ALTHOUGH WE
CANNOT RULE OUT THE THREAT FOR DAMAGING WINDS WITH ANY STORMS THAT
FORM... THE THREAT DOES NOT APPEAR WIDESPREAD.
EXPECT SHOWERS AND THUNDERSTORMS TO DISSIPATE THURSDAY EVENING.
ANOTHER HUMID NIGHT WILL KEEP TEMPERATURES IN THE UPPER 60S AND
LOW 70S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
500 MB HEIGHTS RISE ON FRIDAY AS RIDGING BUILDS IN BRIEFLY...AND
850 TEMPS APPROACH 20 C. EXPECTING THIS BE ONE OF THE MORE HOT AND
HUMID DAYS WE HAVE SEEN THIS SUMMER...AND HEAT INDEX VALUES WILL
LIKELY REACH 100 IN PARTS OF THE SOUTHERN ZONES...AND A HEAT
ADVISORY MAY BE NEEDED THERE. CANNOT RULE OUT A FEW AIR MASS
THUNDERSTORMS...BUT BETTER CHANCE WILL BE IN NORTHERN
ZONES...WHERE STRONGER WINDS ALOFT...AND APPROACHING COLD FRONT
WILL CREATE BETTER DYNAMICS...AND COULD PRODUCE SOME STRONGER
STORMS. LOOK FOR A WARM AND UNCOMFORTABLE NIGHT FRIDAY NIGHT AS
HUMIDITIES REMAIN HIGH AND INCREASED SW FLOW PREVENTS MIN FROM
DROPPING OFF MUCH. COLD FRONT WILL APPROACH NORTHERN ZONES LATE
FRIDAY NIGHT...AND THE THREAT FOR THUNDERSTORMS WILL INCREASE
TOWARD DAYBREAK...AND SHIFT SOUTHWARD TOWARD THROUGH THE DAY.
GIVEN THE GREAT SURFACE INSTABILITY AND THE STRONG MID-UPPER LEVEL
WINDS DROPPING SOUTHWARD AHEAD OF THE FRONT SATURDAY...THE THREAT
FOR SEVERE CONVECTION REMAINS A CONCERN ON SATURDAY...AND THIS
COULD LINGER INTO THE EVENING.
THE FRONT IS EXPECTED TO CLEAR THE COAST LATE SATURDAY NIGHT OR
EARLY SUNDAY...WITH CLEARING AND NOTICEABLY COOLER AND LESS
HUMID CONDITIONS. THE HIGH THAT BUILDS IN BEHIND THE FRONT WILL
LINGER INTO TUESDAY...WITH TEMPS CLOSE TO OR A LITTLE BELOW NORMAL
DURING THIS PERIOD. AN INCREASE IN HUMIDITY AND TEMPS IS POSSIBLE
BY MID-WEEK.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM...THUNDERSTORMS WILL BE POSSIBLE AROUND 00Z IN WESTERN
NEW HAMPSHIRE... SPREADING SOUTH AND EAST THROUGH AROUND 4 OR 6 Z.
THE GREATER CHANCE OF THUNDER WILL BE IN NORTHWEST NEW HAMPSHIRE.
OTHERWISE VFR CONDITIONS EXPECTED OUTSIDE OF VALLEY FOG IN THE
CONNECTICUT RIVER VALLEY.
LONG TERM...MAINLY VFR FRIDAY AND FRIDAY NIGHT...WITH FLIGHT
RESTRICTIONS IS CONVECTION EXPECTED ON SATURDAY INTO SATURDAY
EVENING. VFR RETURNS SUNDAY AND MONDAY.
&&
.MARINE...
SHORT TERM...LIGHT WINDS WILL KEEP CONDITIONS QUIET OVER THE WATERS.
LONG TERM...SW FLOW INCREASES AHEAD OF A COLD FRONT FRIDAY NIGHT
INTO SATURDAY WITH SEAS IN EXCESS AROUND 5 FT...AND WINDS APPROACHING
SCA LEVELS. WINDS WILL SHIFT TO NW SATURDAY NIGHT AND DIMINISH.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CEMPA
NEAR TERM...KIMBLE
SHORT TERM...KIMBLE
LONG TERM...CEMPA
AVIATION...CEMPA/KIMBLE
MARINE...CEMPA/KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
928 AM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH FROM THE NORTH TODAY AND WILL DROP
SOUTH THROUGH THE REGION TONIGHT. THE FRONT WILL STALL OVER SOUTHERN
NEW ENGLAND ON THURSDAY AND WILL LIFT BACK TO THE NORTH AS A WARM
FRONT THURSDAY NIGHT. THE WARM FRONT WILL LIFT INTO SOUTHERN CANADA
ON FRIDAY. ANOTHER COLD FRONT WILL DROP SOUTH FROM CANADA FRIDAY
NIGHT AND WILL CROSS THE REGION ON SATURDAY. HIGH PRESSURE WILL
BUILD IN FROM THE NORTHWEST SATURDAY NIGHT THROUGH TUESDAY. HIGH
PRESSURE WILL SHIFT OFFSHORE ON TUESDAY NIGHT AND WILL REMAIN
ANCHORED OFF THE COAST THROUGH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
930AM UPDATE...FORECAST THINKING HAS CHANGED A BIT WITH THIS
UPDATE REGARDING CONVECTION THROUGH TODAY AND TONIGHT. NAM MODEL
HAS BEEN RUNNING VERY WARM ON DEW POINTS RECENTLY... AND AS A
RESULT HAS BEEN GENERATING MORE CAPE THAN HAS BEEN REALIZED THE
PAST FEW DAYS. NAM IS FORECASTING 70 TO 73 DEW POINTS WIDESPREAD
ACROSS THE FORECAST AREA THIS MORNING... AND THIS DOES NOT APPEAR
TO BE LIKELY. CMC MODEL IS MUCH LOWER... WITH MOST AREAS IN THE
MID 60S AWAY FROM THE IMMEDIATE COAST. THE CMC IS IN GOOD
AGREEMENT WITH THE HRRR AS WELL. WITH THE LOWER DEW POINTS...
AFTERNOON SURFACE-BASED CAPE VALUES ARE NOT AS HIGH AND IT WILL BE
HARDER TO BUST THE CAP AND GENERATE CONVECTION. STILL EXPECT A LOW
CHANCE FOR A STRAY SHOWER OR THUNDERSTORM ACROSS THE AREA FROM
AROUND NOON TO 6 PM. BUT THE GREATER THREAT FOR THUNDERSTORMS AND
SEVERE WEATHER WILL NOT ARRIVE UNTIL CLOSER TO 00Z OR 8 PM WHEN
THUNDERSTORMS WHICH FORM OVER ONTARIO AND QUEBEC WITH A SHORTWAVE
TROUGH TRAVEL SOUTHEAST AND CROSS THE CANADIAN BORDER INTO
NORTHERN NEW ENGLAND. HRRR IS SHOWING THIS PROGRESSION VERY WELL
AND THIS WAS USED HEAVILY IN THE FORECAST FOR TODAY. EVEN THE NAM
DOES NOT GENERATE PRECIPITATION UNTIL LATE AFTERNOON... GIVING
MORE CREDENCE TO THE DELAYED THUNDERSTORM FORECAST. DAMAGING WINDS
WILL BE POSSIBLE WITH THIS LINE OF STORMS AS IT MOVES INTO THE
AREA... AND THE STORM PREDICTION CENTER FORECAST AGREES WITH
THIS THREAT. PRIMARY CHANGE WITH THIS UPDATE WAS TO LOWER FORECAST
POPS AND THUNDERSTORM CHANCES THROUGH THE AFTERNOON... AND
INCREASE THEM THIS EVENING.
530 AM UPDATE...THE FIRST SHOWERS OF THE DAY POPPING AROUND
SHERBROOKE THIS MORNING AND HEADING FOR COOS COUNTY. NOTHING
SPECTACULAR TO THIS UPDATE -- JUST SOME REJIGGERING OF THE SKY,
POP AND TEMPERATURE FORECASTS FOR THIS MORNING. REMAINDER OF
FORECAST UNCHANGED.
SEVERE WEATHER THREAT TODAY MAINLY NORTHERN NEW HAMPSHIRE
AND WESTERN MAINE AWAY FROM THE COAST. APPROACHING SHORTWAVE THIS
AFTERNOON WILL DEPRESS THE WESTERLIES AND A FRONTAL BOUNDARY OVER
THE AREA, INCREASING SHEAR WHILE MAINTAINING INSTABILITY. THE
FRONTAL BOUNDARY WILL BE THE FOCUS FOR CONVECTION TODAY BEGINNING
ALONG THE CANADIAN BORDER MIDDAY THEN SHIFTING SOUTHWARD THROUGH
THE AFTERNOON INTO THE EVENING HOURS. STORM PREDICTION CENTER HAS
OUTLINED DAMAGING WIND AS THE BIGGEST THREAT TODAY, WITH A
POSSIBLY ORGANIZED MESOSCALE CONVECTIVE SYSTEM TAKING SHAPE LATER
TODAY AS THE SHEAR PROFILES INCREASE. PRECIPITABLE WATER VALUES
ARE FORECAST TO BE IN THE 1.75-1.90 RANGE THIS AFTERNOON AS WELL
SO WE WILL HAVE TO BE ON THE LOOKOUT FOR TRAINING CELLS AS EACH
STORM WILL PACK HEAVY DOWNPOURS. MAX TEMPERATURES TODAY ABOUT 1-4F
COOLER THAN THE PAST FEW DAYS GIVEN CLOUD COVER EXPECTED THIS
AFTERNOON AND SEA BREEZE PENETRATION ALONG THE COAST.
&&
.SHORT TERM /TONIGHT AND THURSDAY/...
THUNDERSTORMS WIND DOWN AFTER DARK TONIGHT WITH ONLY A CHANCE OF
SHOWERS OVERNIGHT AS THE FRONTAL BOUNDARY WEAKENS IN SOUTHERN NEW
ENGLAND. EXPECT WIDESPREAD PATCHY FOG DEVELOPING OVERNIGHT WITH
LOWS IN THE 60S. THEN ON THURSDAY ANOTHER WARM DAY WITH
TEMPERATURES MAXING OUT FROM THE LOWER 80S IN MOUNTAINS TO THE
LOWER 90S IN SOUTHERN NEW HAMPSHIRE. NOT MUCH FORCING FOR
CONVECTION THURSDAY WITH MODELS SLOW TO PUSH THE DIFFUSE WARM
FRONT BACK NORTH OF OUR REGION UNTIL THURSDAY NIGHT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
STALLED FRONTAL BOUNDARY WILL LIFT BACK NORTH INTO THE REGION AS A
WARM FRONT THURSDAY NIGHT. WILL SEE A CHANCE OF EVENING SHOWERS AND
THUNDERSTORMS MAINLY OVER SOUTHWEST ZONES AND THEN A CHANCE OF
SHOWERS OVERNIGHT THROUGHOUT THE FORECAST AREA. OVERNIGHT LOWS WILL
BE IN THE 60S TO NEAR 70.
WARM FRONT WILL LIFT NORTH OF THE REGION EARLY FRIDAY AND HEAT AND
HUMIDITY WILL BUILD ONCE AGAIN. WILL SEE A CHANCE OF AFTERNOON
THUNDERSTORMS. EXPECT HIGHS IN THE UPPER 80S TO MID 90S IN MOST
AREAS WITH THE EXCEPTION OF MID COAST MAINE WHERE SOMEWHAT OF AN
ONSHORE FLOW WILL HOLD TEMPS IN THE LOWER TO MID 80S.
VERY WARM AND MUGGY FRIDAY NIGHT WITH ANY CONVECTION TAPERING OFF
WITH THE LOSS OF HEATING. COLD FRONT APPROACHING FROM THE NORTH WILL
BRING A CHANCE OF SHOWERS AND THUNDERSTORM TO NORTHERN ZONES AFTER
MIDNIGHT.
SATURDAY STILL LOOKING LIKE A BUSY SEVERE WEATHER DAY. TIMING OF THE
COLD FRONT LOOKING PRIME. FAIRLY STRONG SHEAR FOR THIS TIME OF YEAR
WILL LIKELY RESULT IN STRONG TO SEVERE THUNDERSTORMS WITH THE MAIN
THREAT BEING WIND DAMAGE DURING THE EARLY TO MID AFTERNOON TIME
FRAME. WILL CONTINUE TO HIGHLIGHT THIS THREAT IN THE HWO.
COLD FRONT WILL PUSH OFFSHORE SATURDAY EVENING FINALLY BRINGING SOME
RELIEF FROM THE HEAT AND HUMIDITY. EXPECT ANY LINGERING SHOWERS AND
THUNDERSTORMS TO PUSH OFFSHORE BEFORE MIDNIGHT. LOW TEMPS WILL
BOTTOM OUT IN THE MID TO UPPER 50S IN THE NORTH AND LOWER TO MID 60S
IN THE SOUTH.
HIGH PRESSURE BUILDING IN FROM THE NORTHWEST WILL PROVIDE SEVERAL
DAYS OF NICE SUMMER WEATHER SUNDAY THROUGH TUESDAY. HIGH PRESSURE
WILL SHIFT OFFSHORE TUESDAY NIGHT AND RETURN FLOW WILL BRING WARM
AND MUGGY AIR BACK INTO THE REGION FOR MIDWEEK.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...PATCHY VALLEY FOG THIS MORNING THEN VFR THIS
AFTERNOON WITH AREAS OF MVFR/IFR IN SHOWERS AND THUNDERSTORMS
THROUGH LATE EVENING. PATCHY MVFR AGAIN IN FOG AND HAZE OVERNIGHT
TONIGHT.
LONG TERM...VFR THURSDAY THROUGH SATURDAY WITH AREAS OF IFR/LIFR
VSBY/CEILINGS IN MORNING FOG. AREAS OF MVFR/IFR CONDITIONS DURING
THE DAY IN AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SHORT TERM...SOUTHWESTERLY FLOW INCREASES TODAY BUT NOT ENOUGH TO
DRIVE SEAS TO SMALL CRAFT ADVISORY LEVELS, MAXING OUT AT 2 TO 4
FEET IN THE OUTER WATERS.
LONG TERM...SCA LIKELY ON FRIDAY AND FRIDAY NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE...KIMBLE
SHORT TERM...STJEAN
LONG TERM...SINSABAUGH
AVIATION...STJEAN/SINSABAUGH
MARINE...STJEAN/SINSABAUGH
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1005 PM EDT THU JUL 18 2013
.SYNOPSIS...
ISSUED AT 358 PM EDT THU JUL 18 2013
ONE MORE DAY OF HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS
NORTHERN MICHIGAN FRIDAY BEFORE A COUPLE OF COLD FRONTS PASSING
THROUGH THE GREAT LAKES WILL COOL THINGS DOWN DRAMATICALLY BY
SATURDAY. PASSAGE OF THESE FRONTS WILL BE ACCOMPANIED BY
THUNDERSTORM ACTIVITY...SOME OF WHICH COULD BE SEVERE OVERNIGHT
AND INTO FRIDAY. THE SEVERE WEATHER THREAT WILL END BY FRIDAY
EVENING...WITH A DRY AND PLEASANT WEEKEND ON TAP.
&&
.UPDATE...
ISSUED AT 1005 PM EDT THU JUL 18 2013
SEVERE THUNDERSTORM WATCH CONTINUES LATE THIS EVENING FOR ERN UPR
MICHIGAN AND THE TIP OF THE MITT. CONVECTIVE LINE (LEWP) HAS
SPREAD ACROSS ALL OF ERN UPR MICHIGAN...WITH THE LEADING EDGE NOW
IN THE STRAITS AREA. A FEW STORMS WITHIN THIS LINE HAVE BECOME
VERY STRONG/LOW END SEVERE...BUT DID SHOW AN OVERALL DOWNWARD
TREND IN INTENSITY AS IT ENTERED OUR NRN ZONES. AT THIS
POINT...WILL KEEP THE WATCH GOING GIVEN THE POTENTIAL FOR A FEW
ADDITIONAL STRONG/SEVERE STORMS IN RESPONSE TO STRENGTHEN WIND
SHEAR AS A 45 TO 50 KT JET MAX LEANS INTO THE AREA LATE TONIGHT.
WILL ALSO KEEP AN EYE ON THE NEXT LINE OF CONVECTION NOW MOVING
E/SE THRU CENTRAL LAKE SUPERIOR AS WE HEAD INTO THE OVERNIGHT
HOURS.
UPDATE ISSUED AT 742 PM EDT THU JUL 18 2013
DIURNAL ENHANCEMENT TO CONVECTION IS QUICKLY DIMINISHING WITH THE
APPROACH OF SUNSET...BRINGING AN END TO THE WIDELY SCATTERED
SHOWERS AND STORMS ACROSS ALL OF NRN LWR MICHIGAN. AFTERNOON
CONVECTION OVER LAKE SUPERIOR HAS FURTHER ORGANIZED INTO A LEWP...
EXTENDING FROM JUST NORTH OF WHITEFISH BAY WESTWARD ALONG THE LAKE
SUPERIOR SHORELINE OF CENTRAL AND ERN UPR MICHIGAN. ADDITIONAL
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED AHEAD OF THIS LINE OF
CONVECTION...WITH THESE CELLS AND THE WHOLE LINE MOVING E/SE. THIS
LINE OF CONVECTION WILL SLIDE THRU ERN UPR MICHIGAN AND THE
STRAITS DURING THE BALANCE OF THE EVENING. VELOCITY DATA HAS SHOWN
SOME EMBEDDED AREAS OF ROTATION WITHIN THE THE LINE...AND WILL
CERTAINLY MONITOR RADAR AS THIS LINE SLIDES THRU OUR NRN CWA.
OVERALL AHEAD WILL STRENGTHEN THRU THE NIGHT AS AS 45 TO 50 KT LOW
LEVEL JET MAX LEANS INTO NRN MICHIGAN. PLENTY OF SURFACE BASED
INSTABILITY WILL REMAIN IN TACT AS WE HEAD THRU THE NIGHT...AS
WILL AMPLE 850 MB THETA E.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
HIGH IMPACT WEATHER POTENTIAL: ISOLATED SEVERE THUNDERSTORMS
POSSIBLE THROUGH EARLY EVENING. INCREASING THREAT FOR DAMAGING
WINDS TONIGHT OVER EASTERN UPPER AND THE TIP OF THE MITT...MOVING
SOUTH INTO NORTHERN LOWER MICHIGAN ON FRIDAY.
HOT AND HUMID WEATHER CONTINUES...WITH HEAT ADVISORIES BEING
CONFINED CLOSER TO SAGINAW BAY FOR THE DAY ON FRIDAY AHEAD OF
ARRIVING COLD FRONT.
OVERVIEW: FLAT RIDGING CONTINUES ACROSS THE GREAT LAKES REGION THIS
AFTERNOON WITH STRONGER SHORTWAVE ENERGY NOW BECOMING EVIDENT
DROPPING OUT OF NORTHERN MANITOBA...WITH AN ADDITIONAL WAVE OVER
SOUTHERN SASKATCHEWAN. AT THE SURFACE...LOW PRESSURE HAS TAKEN
SHAPE OVER EASTERN NORTH DAKOTA THIS HOUR WITH QUASI-STATIONARY
WARM FRONT EXTENDING EAST ACROSS NORTHERN MINNESOTA AND UPPER
MICHIGAN. STORMS HAVE PERCOLATED ALONG THIS BOUNDARY ALL DAY GIVEN
SOUPY WARM SECTOR AIRMASS AND SOUTHWESTERLY WINDS RIDING OVER THE
BOUNDARY IN THE PRESENCE OF AMPLE UNCAPPED INSTABILITY AND GRADUALLY
INCREASING DEEP LAYER SHEAR. ON THE MESOSCALE...AND OUTFLOW
BOUNDARY WORKED SOUTH INTO NORTHERN LOWER HELPING TO TRIGGER
CONVECTION SOUTH OF THE FRONT...WITH SOME OF THIS ACTIVITY ONGOING
AS I TYPE. TEMPS IN AREAS NOT SEEING RAINFALL ARE NOT DISAPPOINTING
THE HOT/HUMID TALK OF LATE...WITH TVC 96 AND CAD 97 THIS HOUR.
THROUGH EARLY EVENING: ISOLATED TO SCATTERED TSRA ACTIVITY WILL
CONTINUE OVER NORTHERN LOWER...ALTHOUGH DECREASING IN COVERAGE AS WE
AWAIT FURTHER DEVELOPMENT UPSTREAM.
TONIGHT: BROAD AREA OF HEIGHT FALLS OVERSPREADS THE GREAT LAKES
REGION AHEAD OF STRONG SHORTWAVE WHOSE CORE WILL BE DROPPING THROUGH
NORTHERN MANITOBA. BENEATH THIS FEATURE THE SURFACE LOW WILL TRACK
NORTH AND EAST...TO NEAR THE SOUTHERN SHORE OF JAMES BAY BY DAYBREAK
FRIDAY. HEIGHT FALLS AND TIME OF DAY WILL COAX A STRENGTHENING LLJ
AT H8 FROM NORTHERN WISCONSIN NORTH AND EAST ACROSS LAKE SUPERIOR.
SYNOPTIC SETUP AND SHEAR PARAMETERS CERTAINLY FAVOR PROGRESSIVE MCS
DEVELOPMENT WITH OVER 30KTS OF 0-3KM BULK SHEAR...BUT NO MORE THAN
10KTS ABOVE THIS TO 6KM. THE QUESTION BECOMES...WHERE IS THIS
CONVECTION LIKELY TO FORM/MOVE?
THE SYNOPTICALLY-FAVORED LOCATION WOULD BE NEAR OR JUST NORTH OF LAKE
SUPERIOR GIVEN THE CURRENT FRONTAL BOUNDARY AND EXPECTED LLJ
LOCATION. THIS IS WELL SHOWN BY THE NEW 12Z NAM AND PROBABLY THE
STRONGEST GUIDANCE CONSENSUS WHICH BRINGS TO DISTINCT CONVECTIVE
COMPLEXES OVER OR NORTH OF MY NORTHERN ZONES. AFTERNOON RADAR
TRENDS...HOWEVER...SUGGEST DEVELOPMENT A LITTLE FURTHER SOUTH AND
WEST...OVER THE ARROWHEAD OF MINNESOTA ALONG OUTFLOW BOUNDARY IN
THIS AREA. EARLY AFTERNOON HRRR IS ONTO THIS TREND...AND WITH
FORWARD-PROPAGATING CORFIDI VECTORS SUGGESTING AN ESE STORM
MOTION...LOOKS TO BRING ACTIVITY TOWARDS EASTERN UPPER LATER THIS
EVENING...WITH PERHAPS MORE ACTIVITY DEVELOPING UPSTREAM THROUGH THE
FIRST HALF OF TONIGHT AS THE LLJ STRENGTHENS IMMEDIATELY AHEAD OF
THE SURFACE COLD FRONT. THUS...WILL INCREASE POPS OVER EASTERN
UPPER TO LIKELY DURING THE EVENING HOURS...BUT KEEP LIKELIES
PRIMARILY RESTRICTED TO EASTERN UPPER OVERNIGHT GIVEN EXPECTED STORM
PROPAGATION. SOME ROGUE STORM DEVELOPMENT TO THE SOUTH IS
POSSIBLE...BUT LOWER POPS WARRANTED HERE. SEVERE THREAT IS
THERE...MORE ISOLATED WIND/HAIL IN THE NEAR TERM...WITH A MORE
ORGANIZED WIND THREAT TAKING SHAPE THIS EVENING.
REALLY LIKE INHERITED VERY WARM OVERNIGHT LOWS GIVEN INCREASING
CLOUD COVER AND COUPLED BOUNDARY LAYER FLOW NOT GIVING TEMPERATURES
MUCH ROOM TO FALL. SO...LOOKING LIKE THE LAST UNCOMFORTABLE SLEEPING
NIGHT MAY BE THE WORST /AT LEAST OVER NORTHERN LOWER/ WHERE MID TO
UPPER 70S SHOULD ABOUT DO IT.
FRIDAY: SOMEWHAT UNUSUAL FOR THE APX CWA SO FAR THIS WARM
SEASON...WE HAVE A COLD FRONT PROGGED TO PUSH THROUGH THE FORECAST
AREA IN THE MIDDLE OF PEAK HEATING. CLEARLY...OVERNIGHT CONVECTIVE
ACTIVITY WILL HAVE A HUGE IMPACT ON WHAT HAPPENS THUNDERSTORM-WISE
DURING THE DAY. COULD VERY WELL BE SOME ONGOING ACTIVITY ACROSS THE
CWA EARLY...WITH THE BEST CHANCES AGAIN BEING OVER EASTERN
UPPER...CLOSEST TO THE ARRIVING COLD FRONT. THIS AT LEAST SPELLS
THE POTENTIAL FOR SOME DESTABILIZATION AHEAD OF AFOREMENTIONED COLD
FRONT /ESP OVER NORTHERN LOWER/ WHICH LOOKS TO PUSH THROUGH THE CWA
IN THE 18-00Z TIME FRAME. SHEAR PARAMETERS ARE IMPRESSIVE AS THE
PRIMARY BELT OF THE WESTERLIES SINKS INTO OUR AREA. 0-3KM BULK
SHEAR REACHES 40KTS...WITH 50KTS+ OF 0-6KM SHEAR. SHEAR LOOKS TO
ONLY HAVE A SLIGHT ANGLE TO THE ARRIVING BOUNDARY...SO A LINEAR MODE
WITH EMBEDDED BOWING SEGMENTS COULD CERTAINLY BE SUPPORTED. THIS IS
WELL CAPTURED BY THE DAY 2 SLIGHT RISK AREA FROM SPC.
AS FOR TEMPERATURES AND HEAT ADVISORY CONCERNS...THE EARLIER
EXPANSION OF THE HEAT ADVISORY TO THE SOUTHEASTERN ZONES FOR THE DAY
LOOKS RIGHT ON...GIVEN STRENGTHENING SOUTHWEST WINDS GIVING SOME
DOWNSLOPING ASSISTANCE TO THESE AREAS...WHICH SHOULD PUSH TEMPS INTO
THE LOW/MID 90S BEFORE CONVECTIVE ACTIVITY ARRIVES FROM THE NORTH
AND WEST. ELSEWHERE...LOW TO MID 80S LOOK GOOD GIVEN EXPECTED CLOUD
COVER AND RAINFALL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
RECENT TRENDS...TEMPERATURES: HOT...OBVIOUSLY. 1-3C ABOVE NORMAL
LAST 7 DAYS AND PRETTY MUCH FOR THE MONTH OF JULY THUS FAR.
PRECIPITATION/HYDROLOGY: BAND OF HEAVIER PRECIPITATION ACROSS
EASTERN UPPER/STRAITS REGION LAST NIGHT (RADAR ESTIMATES 3+ INCHES
FAR WESTERN MACKINAC/SCHOOLCRAFT COUNTIES) MOST SUBSTANTIAL RAINFALL
OF LAST SEVEN DAYS...OUTSIDE OF SCATTERED DIURNAL ACTIVITY MUCH OF
NORTHERN LOWER MICHIGAN HASN`T SEEN A DROP. 30 DAY STANDARDIZED
PRECIP INDEX CONTINUING TO TREND DRIER...ESPECIALLY ACROSS PORTIONS
OF UPPER MICHIGAN THAT SAW GOOD RAINS OVERNIGHT. STREAMFLOWS ON
AREA RIVERS STILL MOSTLY NEAR NORMAL...HYDROGRAPHS FLAT GIVEN LACK
OF RENEWED RUNOFF. TOPSOIL MOISTURE STILL IN GOOD SHAPE DESPITE
RECENT DRYNESS.
LARGE SCALE PATTERN/FORECAST...CONTINENTAL U.S. DOMINATED BY FLAT
RIDGING...WITH THE SOUTHERN EDGE OF THE MAIN WESTERLIES RUNNING
STRAIGHT WEST-EAST ALONG THE CANADIAN BORDER. PATTERN MORE BLOCKY
UPSTREAM ACROSS THE PACIFIC WITH "OFF THE CHART" -EPO/-WPO INDICES.
BALL OF ENERGY EMERGING FROM ABOVE THE ARCTIC CIRCLE AND ENTERING
FAR NORTHERN SASKATCHEWAN/MANITOBA THIS AFTERNOON WILL BE THE
CATALYST TO THE END OF THE CURRENT HEAT AND HUMIDITY THAT HAS BEEN
LINGERING OVER THE UPPER LAKES THIS WEEK. STRONG HEIGHT FALLS WILL
DROP ACROSS THE REGION FRIDAY AND DRIVE COOLER AIR INTO MICHIGAN FOR
THE WEEKEND. QUASI-ZONAL FLOW THEN FORECAST TO SET UP ACROSS THE
NORTHERN HALF OF THE CONUS FOR THE FIRST PART OF NEXT WEEK...WITH
SOME LOW AMPLITUDE TROUGHING FROM THE GREAT LAKES/OHIO VALLEY
NORTHEAST INTO NEW ENGLAND.
AHEAD OF THE CANADIAN HEIGHT FALLS WILL BE A PAIR OF COLD FRONTS
THAT WILL SWEEP ACROSS NORTHERN MICHIGAN FRIDAY/FRIDAY NIGHT. THIS
WILL PUSH A REFRESHINGLY COOLER/DRIER AIR MASS INTO THE UPPER LAKES
SATURDAY...WHILE HIGH PRESSURE SETTLES INTO THE REGION FOR SUNDAY.
HIGH PRESSURE RETREATS TO THE EAST MONDAY WITH RETURN FLOW OF WARMER
AIR BACK INTO THE UPPER MIDWEST/UPPER LAKES GETTING UNDERWAY. MAIN
FORECAST CONCERN THROUGH THE WEEKEND WILL BE WITH THE TRANSITION
FROM WARM/MUGGY TO COOLER WEATHER FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SUNDAY: WEATHER...LEAD COLD FRONT WILL LIKELY
STILL BE IN THE VICINITY OF THE M-72/US-10 CORRIDOR FRIDAY
EVENING...WITH CONVECTION (POTENTIALLY SEVERE) LIKELY ONGOING AHEAD
OF THIS BOUNDARY WHICH SHOULD SINK INTO SOUTHERN LOWER MICHIGAN BY
MIDNIGHT. SECONDARY BOUNDARY COMES IN HOT ON ITS HEELS...PUSHED
ALONG BY THE MAIN SHORT WAVE TROUGH THAT WILL BE DIGGING SOUTHEAST.
MUCH OF THE FORCING ALOFT LOOKS TO REMAIN NORTH OF THE FORECAST
AREA...SOME QG SUBSIDENCE CROSSES NORTHERN MICHIGAN BEHIND THE LEAD
FRONT. SO WILL RUN WITH THUNDERSTORM CHANCES BASICALLY SOUTH OF A
MBL-APN LINE FRIDAY EVENING...AND DRY THINGS OUT THEREAFTER HEADING
INTO SATURDAY. WEAK SHORT WAVE TROUGH WILL TRACK THROUGH THE
MIDWEST SUNDAY...WHICH COULD PUSH CLOUDS INTO NORTHWEST LOWER DURING
THE AFTERNOON HOURS.
WINDS...SHIFTING TO THE NORTHWEST BEHIND SECONDARY COLD FRONT EARLY
SATURDAY MORNING...WINDS WILL BE A BIT GUSTY SATURDAY GIVEN GOOD
POST-FRONTAL MIXING (LOW LEVEL COLD ADVECTION/DIURNAL HEATING) ON
THE ORDER OF 20+MPH. WINDS FORECAST TO SETTLE DOWN SATURDAY NIGHT
AS HIGH BUILDS IN AND GRADIENT DROPS OFF. SUNDAY WINDS WILL BE
LIGHT AND DOMINATED BY LAKE BREEZE EVOLUTION.
TEMPERATURES...OVERNIGHT LOWS SHOULD FINALLY BREAK INTO THE 50S
ACROSS EASTERN UPPER AND MUCH OF NORTHWEST/NORTH CENTRAL LOWER
SATURDAY MORNING. SHOULD SEE A NICE DROP IN HUMIDITY EXPECTED
SATURDAY WITH DEW POINTS FALLING INTO THE 40S DURING THE AFTERNOON.
SATURDAY AFTERNOON HIGHS 65-70 EASTERN UPPER...UPPER 60S-LOWER 70S
MUCH OF NORTHWEST LOWER WITH MID-UPPER 70S NORTHEAST LOWER.
SEASONABLY COOL LOWS FOR SUNDAY MORNING WITH TEMPERATURES DROPPING
INTO THE 40S AWAY FROM THE IMMEDIATE LAKESHORES. SUNDAY HIGHS
AROUND 70-MID 70S EXPECTED.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): MIDWEST SHORT WAVE
CURRENTLY LOOKS AS IF IT WILL PASS SOUTH OF LOWER MICHIGAN AND INTO
THE OHIO VALLEY SUNDAY NIGHT/MONDAY. IF THAT IS THE CASE THEN WILL
PROBABLY START THE NEW WORK WEEK WITH A DRY FORECAST. BETTER THREAT
FOR RAIN MAY ARRIVE WITH A COLD FRONT HEADING INTO THE MIDWEEK
PERIOD...THEN WILL START THE NEW THURSDAY FORECAST OUT DRY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 742 PM EDT THU JUL 18 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU THE FORECAST PERIOD...HOWEVER
CHANCES OF SHOWERS AND STORMS WILL STEADILY INCREASE THROUGHOUT
THE NIGHT AND INTO FRIDAY AS A POTENT COLD FRONT DROPS SE THRU NRN
MICHIGAN. LOW LEVEL SW FLOW WILL INCREASE AHEAD OF THE FRONT...
LENDING TO THE DEVELOPMENT OF LLWS TONIGHT INTO FRIDAY MORNING.
LOW LEVEL WINDS WILL BE STRONGER IN AND AROUND THUNDERSTORMS.
&&
.MARINE...
ISSUED AT 358 PM EDT THU JUL 18 2013
SUMMARY: A LOW PRESSURE SYSTEM WILL PASS NORTH OF THE GREAT LAKES
TONIGHT AND ON FRIDAY...WITH STRENGTHENING SOUTHWESTERLY WINDS
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. NORTHWEST WINDS WILL
DEVELOP IN THE WAKE OF THIS SYSTEM ON SATURDAY WITH VERY QUIET
CONDITIONS TO END THE WEEKEND AS HIGH PRESSURE SETTLES OVERHEAD.
WILL ISSUE SMALL CRAFTS FOR LATE TONIGHT AND FRIDAY ACROSS MOST OF
NORTHERN LAKE MICHIGAN GIVEN THE STRENGTHENING SOUTHWESTERLY FLOW
THIS EVENING. THESE WILL LIKELY NEED TO BE EXPANDED EAST INTO PARTS
OF LAKE HURON ON FRIDAY. MARGINAL SCA/S MAY AGAIN BE NECESSARY ON
SATURDAY GIVEN STRENGTHENING NORTHWEST FLOW.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL 8 AM EDT FRIDAY FOR MIZ016>034.
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR MIZ035-036-041-042.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT FRIDAY FOR LMZ323-341-342-
344>346.
LS...NONE.
&&
$$
UPDATE...MR
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...MR
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
742 PM EDT THU JUL 18 2013
.SYNOPSIS...
ISSUED AT 358 PM EDT THU JUL 18 2013
ONE MORE DAY OF HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS
NORTHERN MICHIGAN FRIDAY BEFORE A COUPLE OF COLD FRONTS PASSING
THROUGH THE GREAT LAKES WILL COOL THINGS DOWN DRAMATICALLY BY
SATURDAY. PASSAGE OF THESE FRONTS WILL BE ACCOMPANIED BY
THUNDERSTORM ACTIVITY...SOME OF WHICH COULD BE SEVERE OVERNIGHT
AND INTO FRIDAY. THE SEVERE WEATHER THREAT WILL END BY FRIDAY
EVENING...WITH A DRY AND PLEASANT WEEKEND ON TAP.
&&
.UPDATE...
ISSUED AT 742 PM EDT THU JUL 18 2013
DIURNAL ENHANCEMENT TO CONVECTION IS QUICKLY DIMINISHING WITH THE
APPROACH OF SUNSET...BRINGING AN END TO THE WIDELY SCATTERED
SHOWERS AND STORMS ACROSS ALL OF NRN LWR MICHIGAN. AFTERNOON
CONVECTION OVER LAKE SUPERIOR HAS FURTHER ORGANIZED INTO A LEWP...
EXTENDING FROM JUST NORTH OF WHITEFISH BAY WESTWARD ALONG THE LAKE
SUPERIOR SHORELINE OF CENTRAL AND ERN UPR MICHIGAN. ADDITIONAL
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED AHEAD OF THIS LINE OF
CONVECTION...WITH THESE CELLS AND THE WHOLE LINE MOVING E/SE. THIS
LINE OF CONVECTION WILL SLIDE THRU ERN UPR MICHIGAN AND THE
STRAITS DURING THE BALANCE OF THE EVENING. VELOCITY DATA HAS SHOWN
SOME EMBEDDED AREAS OF ROTATION WITHIN THE THE LINE...AND WILL
CERTAINLY MONITOR RADAR AS THIS LINE SLIDES THRU OUR NRN CWA.
OVERALL AHEAD WILL STRENGTHEN THRU THE NIGHT AS AS 45 TO 50 KT LOW
LEVEL JET MAX LEANS INTO NRN MICHIGAN. PLENTY OF SURFACE BASED
INSTABILITY WILL REMAIN IN TACT AS WE HEAD THRU THE NIGHT...AS
WILL AMPLE 850 MB THETA E.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
HIGH IMPACT WEATHER POTENTIAL: ISOLATED SEVERE THUNDERSTORMS
POSSIBLE THROUGH EARLY EVENING. INCREASING THREAT FOR DAMAGING
WINDS TONIGHT OVER EASTERN UPPER AND THE TIP OF THE MITT...MOVING
SOUTH INTO NORTHERN LOWER MICHIGAN ON FRIDAY.
HOT AND HUMID WEATHER CONTINUES...WITH HEAT ADVISORIES BEING
CONFINED CLOSER TO SAGINAW BAY FOR THE DAY ON FRIDAY AHEAD OF
ARRIVING COLD FRONT.
OVERVIEW: FLAT RIDGING CONTINUES ACROSS THE GREAT LAKES REGION THIS
AFTERNOON WITH STRONGER SHORTWAVE ENERGY NOW BECOMING EVIDENT
DROPPING OUT OF NORTHERN MANITOBA...WITH AN ADDITIONAL WAVE OVER
SOUTHERN SASKATCHEWAN. AT THE SURFACE...LOW PRESSURE HAS TAKEN
SHAPE OVER EASTERN NORTH DAKOTA THIS HOUR WITH QUASI-STATIONARY
WARM FRONT EXTENDING EAST ACROSS NORTHERN MINNESOTA AND UPPER
MICHIGAN. STORMS HAVE PERCOLATED ALONG THIS BOUNDARY ALL DAY GIVEN
SOUPY WARM SECTOR AIRMASS AND SOUTHWESTERLY WINDS RIDING OVER THE
BOUNDARY IN THE PRESENCE OF AMPLE UNCAPPED INSTABILITY AND GRADUALLY
INCREASING DEEP LAYER SHEAR. ON THE MESOSCALE...AND OUTFLOW
BOUNDARY WORKED SOUTH INTO NORTHERN LOWER HELPING TO TRIGGER
CONVECTION SOUTH OF THE FRONT...WITH SOME OF THIS ACTIVITY ONGOING
AS I TYPE. TEMPS IN AREAS NOT SEEING RAINFALL ARE NOT DISAPPOINTING
THE HOT/HUMID TALK OF LATE...WITH TVC 96 AND CAD 97 THIS HOUR.
THROUGH EARLY EVENING: ISOLATED TO SCATTERED TSRA ACTIVITY WILL
CONTINUE OVER NORTHERN LOWER...ALTHOUGH DECREASING IN COVERAGE AS WE
AWAIT FURTHER DEVELOPMENT UPSTREAM.
TONIGHT: BROAD AREA OF HEIGHT FALLS OVERSPREADS THE GREAT LAKES
REGION AHEAD OF STRONG SHORTWAVE WHOSE CORE WILL BE DROPPING THROUGH
NORTHERN MANITOBA. BENEATH THIS FEATURE THE SURFACE LOW WILL TRACK
NORTH AND EAST...TO NEAR THE SOUTHERN SHORE OF JAMES BAY BY DAYBREAK
FRIDAY. HEIGHT FALLS AND TIME OF DAY WILL COAX A STRENGTHENING LLJ
AT H8 FROM NORTHERN WISCONSIN NORTH AND EAST ACROSS LAKE SUPERIOR.
SYNOPTIC SETUP AND SHEAR PARAMETERS CERTAINLY FAVOR PROGRESSIVE MCS
DEVELOPMENT WITH OVER 30KTS OF 0-3KM BULK SHEAR...BUT NO MORE THAN
10KTS ABOVE THIS TO 6KM. THE QUESTION BECOMES...WHERE IS THIS
CONVECTION LIKELY TO FORM/MOVE?
THE SYNOPTICALLY-FAVORED LOCATION WOULD BE NEAR OR JUST NORTH OF LAKE
SUPERIOR GIVEN THE CURRENT FRONTAL BOUNDARY AND EXPECTED LLJ
LOCATION. THIS IS WELL SHOWN BY THE NEW 12Z NAM AND PROBABLY THE
STRONGEST GUIDANCE CONSENSUS WHICH BRINGS TO DISTINCT CONVECTIVE
COMPLEXES OVER OR NORTH OF MY NORTHERN ZONES. AFTERNOON RADAR
TRENDS...HOWEVER...SUGGEST DEVELOPMENT A LITTLE FURTHER SOUTH AND
WEST...OVER THE ARROWHEAD OF MINNESOTA ALONG OUTFLOW BOUNDARY IN
THIS AREA. EARLY AFTERNOON HRRR IS ONTO THIS TREND...AND WITH
FORWARD-PROPAGATING CORFIDI VECTORS SUGGESTING AN ESE STORM
MOTION...LOOKS TO BRING ACTIVITY TOWARDS EASTERN UPPER LATER THIS
EVENING...WITH PERHAPS MORE ACTIVITY DEVELOPING UPSTREAM THROUGH THE
FIRST HALF OF TONIGHT AS THE LLJ STRENGTHENS IMMEDIATELY AHEAD OF
THE SURFACE COLD FRONT. THUS...WILL INCREASE POPS OVER EASTERN
UPPER TO LIKELY DURING THE EVENING HOURS...BUT KEEP LIKELIES
PRIMARILY RESTRICTED TO EASTERN UPPER OVERNIGHT GIVEN EXPECTED STORM
PROPAGATION. SOME ROGUE STORM DEVELOPMENT TO THE SOUTH IS
POSSIBLE...BUT LOWER POPS WARRANTED HERE. SEVERE THREAT IS
THERE...MORE ISOLATED WIND/HAIL IN THE NEAR TERM...WITH A MORE
ORGANIZED WIND THREAT TAKING SHAPE THIS EVENING.
REALLY LIKE INHERITED VERY WARM OVERNIGHT LOWS GIVEN INCREASING
CLOUD COVER AND COUPLED BOUNDARY LAYER FLOW NOT GIVING TEMPERATURES
MUCH ROOM TO FALL. SO...LOOKING LIKE THE LAST UNCOMFORTABLE SLEEPING
NIGHT MAY BE THE WORST /AT LEAST OVER NORTHERN LOWER/ WHERE MID TO
UPPER 70S SHOULD ABOUT DO IT.
FRIDAY: SOMEWHAT UNUSUAL FOR THE APX CWA SO FAR THIS WARM
SEASON...WE HAVE A COLD FRONT PROGGED TO PUSH THROUGH THE FORECAST
AREA IN THE MIDDLE OF PEAK HEATING. CLEARLY...OVERNIGHT CONVECTIVE
ACTIVITY WILL HAVE A HUGE IMPACT ON WHAT HAPPENS THUNDERSTORM-WISE
DURING THE DAY. COULD VERY WELL BE SOME ONGOING ACTIVITY ACROSS THE
CWA EARLY...WITH THE BEST CHANCES AGAIN BEING OVER EASTERN
UPPER...CLOSEST TO THE ARRIVING COLD FRONT. THIS AT LEAST SPELLS
THE POTENTIAL FOR SOME DESTABILIZATION AHEAD OF AFOREMENTIONED COLD
FRONT /ESP OVER NORTHERN LOWER/ WHICH LOOKS TO PUSH THROUGH THE CWA
IN THE 18-00Z TIME FRAME. SHEAR PARAMETERS ARE IMPRESSIVE AS THE
PRIMARY BELT OF THE WESTERLIES SINKS INTO OUR AREA. 0-3KM BULK
SHEAR REACHES 40KTS...WITH 50KTS+ OF 0-6KM SHEAR. SHEAR LOOKS TO
ONLY HAVE A SLIGHT ANGLE TO THE ARRIVING BOUNDARY...SO A LINEAR MODE
WITH EMBEDDED BOWING SEGMENTS COULD CERTAINLY BE SUPPORTED. THIS IS
WELL CAPTURED BY THE DAY 2 SLIGHT RISK AREA FROM SPC.
AS FOR TEMPERATURES AND HEAT ADVISORY CONCERNS...THE EARLIER
EXPANSION OF THE HEAT ADVISORY TO THE SOUTHEASTERN ZONES FOR THE DAY
LOOKS RIGHT ON...GIVEN STRENGTHENING SOUTHWEST WINDS GIVING SOME
DOWNSLOPING ASSISTANCE TO THESE AREAS...WHICH SHOULD PUSH TEMPS INTO
THE LOW/MID 90S BEFORE CONVECTIVE ACTIVITY ARRIVES FROM THE NORTH
AND WEST. ELSEWHERE...LOW TO MID 80S LOOK GOOD GIVEN EXPECTED CLOUD
COVER AND RAINFALL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
RECENT TRENDS...TEMPERATURES: HOT...OBVIOUSLY. 1-3C ABOVE NORMAL
LAST 7 DAYS AND PRETTY MUCH FOR THE MONTH OF JULY THUS FAR.
PRECIPITATION/HYDROLOGY: BAND OF HEAVIER PRECIPITATION ACROSS
EASTERN UPPER/STRAITS REGION LAST NIGHT (RADAR ESTIMATES 3+ INCHES
FAR WESTERN MACKINAC/SCHOOLCRAFT COUNTIES) MOST SUBSTANTIAL RAINFALL
OF LAST SEVEN DAYS...OUTSIDE OF SCATTERED DIURNAL ACTIVITY MUCH OF
NORTHERN LOWER MICHIGAN HASN`T SEEN A DROP. 30 DAY STANDARDIZED
PRECIP INDEX CONTINUING TO TREND DRIER...ESPECIALLY ACROSS PORTIONS
OF UPPER MICHIGAN THAT SAW GOOD RAINS OVERNIGHT. STREAMFLOWS ON
AREA RIVERS STILL MOSTLY NEAR NORMAL...HYDROGRAPHS FLAT GIVEN LACK
OF RENEWED RUNOFF. TOPSOIL MOISTURE STILL IN GOOD SHAPE DESPITE
RECENT DRYNESS.
LARGE SCALE PATTERN/FORECAST...CONTINENTAL U.S. DOMINATED BY FLAT
RIDGING...WITH THE SOUTHERN EDGE OF THE MAIN WESTERLIES RUNNING
STRAIGHT WEST-EAST ALONG THE CANADIAN BORDER. PATTERN MORE BLOCKY
UPSTREAM ACROSS THE PACIFIC WITH "OFF THE CHART" -EPO/-WPO INDICES.
BALL OF ENERGY EMERGING FROM ABOVE THE ARCTIC CIRCLE AND ENTERING
FAR NORTHERN SASKATCHEWAN/MANITOBA THIS AFTERNOON WILL BE THE
CATALYST TO THE END OF THE CURRENT HEAT AND HUMIDITY THAT HAS BEEN
LINGERING OVER THE UPPER LAKES THIS WEEK. STRONG HEIGHT FALLS WILL
DROP ACROSS THE REGION FRIDAY AND DRIVE COOLER AIR INTO MICHIGAN FOR
THE WEEKEND. QUASI-ZONAL FLOW THEN FORECAST TO SET UP ACROSS THE
NORTHERN HALF OF THE CONUS FOR THE FIRST PART OF NEXT WEEK...WITH
SOME LOW AMPLITUDE TROUGHING FROM THE GREAT LAKES/OHIO VALLEY
NORTHEAST INTO NEW ENGLAND.
AHEAD OF THE CANADIAN HEIGHT FALLS WILL BE A PAIR OF COLD FRONTS
THAT WILL SWEEP ACROSS NORTHERN MICHIGAN FRIDAY/FRIDAY NIGHT. THIS
WILL PUSH A REFRESHINGLY COOLER/DRIER AIR MASS INTO THE UPPER LAKES
SATURDAY...WHILE HIGH PRESSURE SETTLES INTO THE REGION FOR SUNDAY.
HIGH PRESSURE RETREATS TO THE EAST MONDAY WITH RETURN FLOW OF WARMER
AIR BACK INTO THE UPPER MIDWEST/UPPER LAKES GETTING UNDERWAY. MAIN
FORECAST CONCERN THROUGH THE WEEKEND WILL BE WITH THE TRANSITION
FROM WARM/MUGGY TO COOLER WEATHER FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SUNDAY: WEATHER...LEAD COLD FRONT WILL LIKELY
STILL BE IN THE VICINITY OF THE M-72/US-10 CORRIDOR FRIDAY
EVENING...WITH CONVECTION (POTENTIALLY SEVERE) LIKELY ONGOING AHEAD
OF THIS BOUNDARY WHICH SHOULD SINK INTO SOUTHERN LOWER MICHIGAN BY
MIDNIGHT. SECONDARY BOUNDARY COMES IN HOT ON ITS HEELS...PUSHED
ALONG BY THE MAIN SHORT WAVE TROUGH THAT WILL BE DIGGING SOUTHEAST.
MUCH OF THE FORCING ALOFT LOOKS TO REMAIN NORTH OF THE FORECAST
AREA...SOME QG SUBSIDENCE CROSSES NORTHERN MICHIGAN BEHIND THE LEAD
FRONT. SO WILL RUN WITH THUNDERSTORM CHANCES BASICALLY SOUTH OF A
MBL-APN LINE FRIDAY EVENING...AND DRY THINGS OUT THEREAFTER HEADING
INTO SATURDAY. WEAK SHORT WAVE TROUGH WILL TRACK THROUGH THE
MIDWEST SUNDAY...WHICH COULD PUSH CLOUDS INTO NORTHWEST LOWER DURING
THE AFTERNOON HOURS.
WINDS...SHIFTING TO THE NORTHWEST BEHIND SECONDARY COLD FRONT EARLY
SATURDAY MORNING...WINDS WILL BE A BIT GUSTY SATURDAY GIVEN GOOD
POST-FRONTAL MIXING (LOW LEVEL COLD ADVECTION/DIURNAL HEATING) ON
THE ORDER OF 20+MPH. WINDS FORECAST TO SETTLE DOWN SATURDAY NIGHT
AS HIGH BUILDS IN AND GRADIENT DROPS OFF. SUNDAY WINDS WILL BE
LIGHT AND DOMINATED BY LAKE BREEZE EVOLUTION.
TEMPERATURES...OVERNIGHT LOWS SHOULD FINALLY BREAK INTO THE 50S
ACROSS EASTERN UPPER AND MUCH OF NORTHWEST/NORTH CENTRAL LOWER
SATURDAY MORNING. SHOULD SEE A NICE DROP IN HUMIDITY EXPECTED
SATURDAY WITH DEW POINTS FALLING INTO THE 40S DURING THE AFTERNOON.
SATURDAY AFTERNOON HIGHS 65-70 EASTERN UPPER...UPPER 60S-LOWER 70S
MUCH OF NORTHWEST LOWER WITH MID-UPPER 70S NORTHEAST LOWER.
SEASONABLY COOL LOWS FOR SUNDAY MORNING WITH TEMPERATURES DROPPING
INTO THE 40S AWAY FROM THE IMMEDIATE LAKESHORES. SUNDAY HIGHS
AROUND 70-MID 70S EXPECTED.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): MIDWEST SHORT WAVE
CURRENTLY LOOKS AS IF IT WILL PASS SOUTH OF LOWER MICHIGAN AND INTO
THE OHIO VALLEY SUNDAY NIGHT/MONDAY. IF THAT IS THE CASE THEN WILL
PROBABLY START THE NEW WORK WEEK WITH A DRY FORECAST. BETTER THREAT
FOR RAIN MAY ARRIVE WITH A COLD FRONT HEADING INTO THE MIDWEEK
PERIOD...THEN WILL START THE NEW THURSDAY FORECAST OUT DRY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 742 PM EDT THU JUL 18 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU THE FORECAST PERIOD...HOWEVER
CHANCES OF SHOWERS AND STORMS WILL STEADILY INCREASE THROUGHOUT
THE NIGHT AND INTO FRIDAY AS A POTENT COLD FRONT DROPS SE THRU NRN
MICHIGAN. LOW LEVEL SW FLOW WILL INCREASE AHEAD OF THE FRONT...
LENDING TO THE DEVELOPMENT OF LLWS TONIGHT INTO FRIDAY MORNING.
LOW LEVEL WINDS WILL BE STRONGER IN AND AROUND THUNDERSTORMS.
&&
.MARINE...
ISSUED AT 358 PM EDT THU JUL 18 2013
SUMMARY: A LOW PRESSURE SYSTEM WILL PASS NORTH OF THE GREAT LAKES
TONIGHT AND ON FRIDAY...WITH STRENGTHENING SOUTHWESTERLY WINDS
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. NORTHWEST WINDS WILL
DEVELOP IN THE WAKE OF THIS SYSTEM ON SATURDAY WITH VERY QUIET
CONDITIONS TO END THE WEEKEND AS HIGH PRESSURE SETTLES OVERHEAD.
WILL ISSUE SMALL CRAFTS FOR LATE TONIGHT AND FRIDAY ACROSS MOST OF
NORTHERN LAKE MICHIGAN GIVEN THE STRENGTHENING SOUTHWESTERLY FLOW
THIS EVENING. THESE WILL LIKELY NEED TO BE EXPANDED EAST INTO PARTS
OF LAKE HURON ON FRIDAY. MARGINAL SCA/S MAY AGAIN BE NECESSARY ON
SATURDAY GIVEN STRENGTHENING NORTHWEST FLOW.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL 8 AM EDT FRIDAY FOR MIZ016>034.
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR MIZ035-036-041-042.
LH...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EDT FRIDAY
FOR LMZ323-342-344>346.
LS...NONE.
&&
$$
UPDATE...MR
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...MR
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
132 AM EDT WED JUL 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 345 PM EDT TUE JUL 16 2013
UPPER AIR PATTERN CONSISTS OF A STRONG 500 MB RIDGE OVER THE LOWER
GREAT LAKES WITH A TROUGH OVER SOUTH CENTRAL CANADA WITH CLOSED LOWS
OFF THE CA COAST AND ONE OVER ERN NM. THE 500 MB RIDGE REMAINS
STATIONARY TODAY WITH THE TROUGH CONTINUING TO MOVE EAST ACROSS
CENTRAL CANADA. THIS TROUGH HELPS TO START PUSHING DOWN THE RIDGE
THIS FORECAST PERIOD WITH THE WESTERLIES ALONG THE CANADIAN/U.S.
BORDER MOVING SLOWLY SOUTH WITH A COLD FRONT MOVING SLOWLY SOUTH AS
WELL.
SPOTTY CONVECTION THAT HAS BEEN KICKED OFF THIS AFTERNOON WAS CAUSED
BY REACHING CONVECTIVE TEMPERATURE WHICH WAS IN THE UPPER 80S. 12Z
GRB SOUNDING HAD A CONVECTIVE TEMPERATURE OF 87 AND THIS SEEMS TO BE
WHAT TEMPERATURES HAVE TO GET TO TO KICK OFF CONVECTION. RUC IS ALSO
SHOWING A 500 MB SPEED MAX JUST TO THE NORTH OF THE AREA AND WITH
MOISTURE ADVECTION...THIS ALSO HELPED TO KICK OFF THE CONVECTION
THIS AFTERNOON. LOOK FOR THIS TO CONTINUE INTO THE EVENING BEFORE
INSTABILITY DIMINISHES WITH LOSS OF HEATING TO STOP THE
THUNDERSTORMS FROM CONTINUING TO DEVELOP. STUFF HAS BEEN FAIRLY
SHORT LIVED AND EXPECT THAT TREND TO CONTINUE THIS AFTERNOON INTO
THIS EVENING.
BUMPED UP SOME LOW TEMPERATURES TONIGHT WITH A SOUTHWEST WIND
ALLOWING DOWNSLOPE TO CONTINUE AND A FEW SW AFFECTED DOWNSLOPE AREAS
COULD HAVE LOWS IN THE MID 70S TONIGHT WHICH IS VERY WARM.
OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES FOR HIGHS ON WED. AGREE WITH SPC OUTLOOK FOR SLIGHT
RISK OF SEVERE THUNDERSTORMS TOMORROW WITH UNIDIRECTIONAL WINDS AND
POOLING OF MOISTURE NEAR THE FRONT TO ALLOW STORMS WITH HIGH WINDS
TO DEVELOP WHICH WOULD BE THE MAIN THREAT FOR SEVERE WEATHER. FRONT
STARTS TO SAG DOWN INTO THE AREA AS WELL SO A FOCUSING MECHANISM FOR
CONVECTION IS THERE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 PM EDT TUE JUL 16 2013
WEDNESDAY NIGHT...THE VERY SLOW MOVING COLD FRONT STRETCHING FROM
NORTH DAKOTA EASTWARD INTO SOUTHWESTERN QUEBEC WILL BECOME
STATIONARY OVERNIGHT WEDNESDAY NIGHT. AT THE SAME TIME HEIGHT FALLS
ASSOCIATED WITH THE UPPER LEVEL 500MB LOW OVER JAMES BAY WILL BEGIN
TO SINK SLOWLY SOUTHWARD AS IT SLOWLY WEAKENS THE HIGH PRESSURE
RIDGE THAT REMAINS OVER MUCH OF THE SOUTHEASTERN U.S. WITH THE FRONT
STRETCHING ACROSS MUCH OF LAKE SUPERIOR INTO THE NORTHERN PORTIONS
OF THE U.P. EXPECT THAT FORCING WILL BE GREAT ENOUGH TO ENHANCE THE
CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE AREA.
CONVERGENCE ASSOCIATED WITH A 25 TO 30 KNOT 850MB LLJ OVER CENTRAL
MN INTO NORTHERN WI WILL KEEP SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH THE OVERNIGHT HOURS...EVEN WITH THE LOSS OF DAYTIME
HEATING. DURING THE OVERNIGHT HOURS...THE CWA WILL ALSO BE UNDER
THE INFLUENCE OF THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL 300MB
JET MAX...HELPING TO INCREASE FORCING FOR ASCENT. MU CAPE VALUES
OVERNIGHT ARE STILL EXPECTED TO BE AROUND 1000-1500 J/KG WITH DEEP
LAYER SHEAR VALUES ON THE ORDER OF 30 TO 35 KNOTS ACROSS THE AREA.
THE SHEAR IS UNIDIRECTIONAL...WHICH WOULD ALSO FAVOR MORE OF A WIND
THREAT. IT WOULD DEFINITELY NOT BE OUT OF THE QUESTION FOR SOME OF
THE STORMS TO BE FAIRLY STRONG OR EVEN SEVERE. THE MAIN THREAT FROM
THESE STORMS WOULD BE STRONG GUSTY WINDS AS DRY AIR REMAINS IN THE
MID LEVELS ALONG WITH AN INVERTED V TYPE SOUNDING IN THE LOW LEVELS
THROUGH THE OVERNIGHT HOURS...HELPING TO INCREASE COLD POOL
DEVELOPMENT. IT SHOULD BE KEPT IN MIND THAT MUCH OF THIS DEPENDS ON
CONVECTIVE DEVELOPMENT/TRACK THROUGH THE DAYTIME HOURS WEDNESDAY.
THURSDAY THROUGH FRIDAY...THE STATIONARY FRONT POSITIONED OVER LAKE
SUPERIOR THURSDAY MORNING IS PROGGED BY THE GFS/EC/GEM TO BEGIN
LIFTING NORTHWARD AS A WARM FRONT DURING THE AFTERNOON HOURS
THURSDAY. THIS FRONT WILL CONTINUE TO LIFT NORTHWARD INTO ONTARIO
DURING THE EVENING HOURS AS A COLD FRONT IS PUSHED SOUTHEASTWARD OUT
OF SOUTHERN MANITOBA INTO NORTHEASTERN MN DURING THE OVERNIGHT
HOURS AS THE UPPER LEVEL TROUGH BEGINS TO DIG INTO THE REGION. WITH
THE FRONT LIFTING NORTHWARD DURING THE DAY THURSDAY...IT WOULD NOT
BE OUT OF THE QUESTION TO SEE THE CLOUDS BREAK UP OVER THE
AREA...WHICH WILL HELP TO INCREASE THE CHANCES FOR SEVERE WEATHER
ACROSS THE CWA AS INSTABILITY INCREASES TO AROUND 1500-2500 J/KG.
DEEP LAYER SHEAR VALUES THROUGH THE DAY THURSDAY ARE PROGGED TO BE
AROUND 35 TO 40 KNOTS WHICH WOULD BE FAVORABLE FOR SEVERE WEATHER
DEVELOPMENT. THURSDAY AND THURSDAY EVENING WIND PROFILES INDICATED
THAT BOTH SPEED AND DIRECTIONAL SHEAR ARE AVAILABLE WHICH WOULD
SUPPORT A MORE ORGANIZED SEVERE EVENT. WHILE THE SOUNDING GAINS A
BIT MORE MOISTURE THROUGHOUT...DRY AIR REMAINS IN PORTIONS OF THE
LOWER LEVELS ALLOWING FOR AN INCREASED SEVERE WIND THREAT THROUGH
THE DAY THURSDAY INTO THE EVENING HOURS. A GREAT DEAL OF THE SEVERE
THREAT DURING THE DAY THURSDAY IS DEPENDENT UPON CLOUD COVER.
OVERNIGHT THURSDAY THROUGH FRIDAY MORNING THE COLD FRONT TO THE
NORTHWEST OF THE AREA WILL CONTINUE SOUTHEASTWARD PUSHING SOUTHEAST
OF THE AREA BY LATE FRIDAY AFTERNOON. AHEAD OF THE COLD FRONT
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE LIKELY. STRONG TO
SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH EARLY FRIDAY MORNING
AS 0-6KM SHEAR VALUES ARE EXPECTED TO BE AROUND 40 TO 45 KNOTS ALONG
AND AHEAD OF THE FRONT...WITH SHEAR VECTORS BECOMING PERPENDICULAR
TO THE FORCING. THE SEVERE THREAT WILL SHIFT SOUTHEASTWARD INTO THE
LOWER GREAT LAKES BY FRIDAY AFTERNOON AS THE FRONT SHIFTS OUT OF THE
AREA. WITH THAT BEING SAID A FEW SHOWERS MAY LINGER INTO THE
AFTERNOON HOURS AS THE UPPER LEVEL 500MB THROUGH MOVES DIRECTLY
OVERHEAD.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...FRIDAY NIGHT THE UPPER LEVEL
500MB TROUGH AXIS LINGERS OVER THE UPPER GREAT LAKES ALONG WITH
REMNANT MOISTURE. THIS WILL KEEP THE CHANCE OF ISOLATED SHOWERS IN
THE FORECAST THROUGH FRIDAY NIGHT. SATURDAY...HIGH PRESSURE BUILDING
OVER SOUTHERN CANADA INTO THE NORTHERN PLAINS WILL BEGIN BUILDING
EASTWARD INTO THE GREAT LAKES REGION. AS THIS HAPPENS FLOW AROUND
THE EASTERN SIDE OF THE HIGH WILL ALLOW DRY AIR FROM CANADA TO SPILL
SOUTHWARD HELPING TO CLEAR THE SKIES FOR THE WEEKEND AND DRY THINGS
OUT A BIT. THIS HIGH IS PROGGED TO REMAIN IN THE AREA THROUGH
SUNDAY NIGHT.
MONDAY THROUGH TUESDAY...DIFFERENCES REMAIN IN MODEL SOLUTIONS TO
THE WEATHER PATTERN FOR THE FIRST HALF OF NEXT WEEK. THE GFS KEEPS
ZONAL TO SLIGHTLY RIDGED FLOW AT 500MB ACROSS THE AREA THROUGH THIS
TIME PERIOD WHILE THE EC BRINGS AND UPPER LEVEL TROUGH INTO THE
REGION. AT THE SAME TIME THE GFS PLACES A SURFACE HIGH OVER THE AREA
WHILE THE EC BUILDS A SURFACE LOW INTO THE REGION OUT OF SOUTHERN
CANADA. WITH THIS CONTINUED DISCONTINUITY...WILL STICK WITH A
CONSENSUS OF THE MODELS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 131 AM EDT WED JUL 17 2013
VFR CONDITIONS SHOULD CONTINUE THROUGH THE PERIOD AT ALL SITES.
LOOK FOR MORE SCT TO ISOLD SHRA/TS TO DEVELOP LATE WED MORNING/EARLY
AFTERNOON AS A FRONTAL BOUNDARY MOVES IN FM THE NW. HAVE INCLUDED
PREVAILING -SHRA AND VCTS FOR BOTH KIWD AND KSAW INTO EARLY WED
EVENING BUT WILL LEAVE MENTION OF PREVAILING SHRA OUT OF KCMX WHERE
CONDITIONS WILL BE MORE STABLE NEAR LAKE SUPERIOR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 PM EDT TUE JUL 16 2013
FOG WILL CONTINUE TO BE PATCHY THROUGH WED MORNING ON LAKE SUPERIOR
AS COLD WATER WITH WARM AND HUMID AIR MOVING OVER THE TOP CAUSES FOG
TO FORM. AS THE FRONT STARTS TO COME DOWN ON WED...THIS SHOULD
DISRUPT THE FOG. A LOW PRESSURE SYSTEM AND FRONTAL BOUNDARY WILL
EFFECT THE REGION WEDNESDAY THROUGH FRIDAY...HOWEVER...WINDS SHOULD
REMAIN LIGHT AND GENERALLY LESS THAN 15 KNOTS. HIGH PRESSURE BUILDS
IN FOR MUCH OF THE WEEKEND ALLOWING WINDS TO REMAIN LIGHT AND
VARIABLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...07
LONG TERM...KEC
AVIATION...VOSS
MARINE...07
AREA FORECAST DISCUSSION
NWS DULUTH MN
630 PM CDT THU JUL 18 2013
.AVIATION...LINE OF STRONG TO SEVERE THUNDERSTORMS JUST SOUTH OF
THE INTERNATIONAL BORDER SLOWLY MOVING SOUTH WITH THE CELLS MOVING
GENERALLY EAST. THE LINE SHOULD STAY SOUTH OF THE INL TAF SITE.
VFR CONDITIONS WILL BE THE DOMINATE CONDITION TONIGHT WITH POSSIBLE
MVFR CIGS DUE TO RAIN. VFR CONDITIONS WILL CONTINUE FRIDAY AT INL.
THE LINE WILL AFFECT THE OTHER TAF SITES LATER THIS EVENING WITH
HIB FIRST THEN DLH-BRD BY LATE EVENING AND HYR TOWARD MIDNIGHT.
VFR CONDITIONS BEFORE THE LINE WITH IFR-LIFR POSSIBLE WITH THE
STORMS AND VFR AFTER PASSAGE THROUGH FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 304 PM CDT THU JUL 18 2013/
SHORT TERM.../THROUGH TONIGHT/
THE FOCUS IS ON THE THREAT OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING. THE STORM PREDICTION CENTER HAS POSTED ALL OF THE
NORTHLAND IN AT LEAST A SLIGHT RISK OF SEVERE THUNDERSTORMS...AND
A MODERATE RISK ACROSS THE SOUTHERN HALF OF THE FORECAST AREA.
LARGE HAIL AND HEAVY RAIN MAY BE THE INITIAL MAIN THREATS AND THEN
QUICKLY TRANSITIONING TO A DAMAGING WIND THREAT. THE
MODELS...ESPECIALLY THE HIGH RESOLUTION HRRR AND NCEP WRF
SIMULATED REFLECTIVITY RUNS...HAVE BEEN INDICATING SUPERCELL
THUNDERSTORMS WILL LIKELY DEVELOP IN NW AND NORTH CENTRAL
MINNESOTA LATE THIS AFTERNOON OR EARLY THIS EVENING...AND THEN
CONGEAL INTO A LINE OF STORMS THAT SWEEP THROUGH THE NORTHLAND
THIS EVENING. A SEVERE THUNDERSTORM WATCH WILL LIKELY BE ISSUED
WITHIN THE NEXT HOUR OR SO.
THIS AFTERNOON AND EVENING...MUCH OF THE NORTHLAND HAS HOT AND
MUGGY WEATHER WITH GUSTY SW WINDS AS A FRONT STRETCHES ACROSS
WESTERN ONTARIO TO A LOW IN THE NORTHERN RED RIVER VALLEY. A
STRONG COLD FRONT EXTENDS FROM SW FROM THE LOW THROUGH THE CENTRAL
DAKOTAS. MOST OF THE NORTHLAND...SAVE FOR THE FAR NORTH AND OVER
THE LAKE...HAS DEVELOPED AMPLE SURFACE BASED CAPE UP TO AROUND
3500 J/KG...MAXIMIZED ACROSS THE S AND SW FORECAST AREA. THERE IS
LITTLE IF ANY INHIBITION. DEEP LAYER (0-6KM) WIND SHEAR OF 30 TO
50 KNOTS HAS DEVELOPED...WITH THE HIGHEST SHEAR ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. PRECIPITABLE WATER VALUES ARE
AROUND 1.75 TO 2 INCHES. THERE SHOULD BE INCREASING CHANCES OF
SHOWERS AND STORMS ACROSS THE FORECAST AREA THROUGH THE REST OF
THE AFTERNOON...BUT THE FOCUS WILL BE ON THE WESTERN FORECAST AREA
WHERE THE MODELS HAVE BEEN INDICATING THUNDERSTORMS...LIKELY AT
FIRST SUPERCELLS...WILL DEVELOP IN NW AND NORTH CENTRAL MINNESOTA
LATE THIS AFTERNOON NEAR THE LOW PRESSURE SYSTEM AND APPROACHING
COLD FRONT. CONSIDERING THE AVAILABLE CAPE...CAPE SOUNDING
PROFILES...AND DEEP LAYER WINDS...THE SUPERCELLS COULD EASILY
DEVELOP LARGE HAIL...GUSTY WINDS...AND HEAVY RAIN. A STRAY TORNADO
CANNOT BE RULED OUT. THE STORMS MAY QUICKLY CONGEAL...AS THE
MODELS SUGGEST...INTO A LINE OF STORMS WITH A TRANSITIONING THREAT
TO MAINLY DAMAGING WINDS AND HEAVY RAIN. THIS LINE AND COLD FRONT
COULD SWEEP ESE THROUGH THE REST OF NE MINNESOTA AND THEN NW
WISCONSIN PRETTY QUICKLY THIS EVENING. I ADDED WORDING TO THE
FORECAST TO INCLUDE SEVERE THUNDERSTORMS AND THE LIKELY THREATS
FOR WHEREVER MY PCPN CHANCES ARE LIKELY LATE THIS AFTERNOON
THROUGH AROUND MIDNIGHT...WHICH IS BASICALLY MY BEST GUESS ON THE
HOURLY TIMING OF THE MAIN LINE OF THUNDERSTORMS.
LATE TONIGHT...THE SEVERE WEATHER THREAT SHOULD COME TO AN END
AROUND MIDNIGHT AS THE MAIN LINE OF STORMS MOVES SE OF THE
FORECAST AREA...BUT THERE COULD BE SOME LINGERING SHOWERS AND
STORMS ACROSS THE SE FORECAST AREA NEAR THE FRONT. THERE SHOULD
ALSO BE DECREASING CHANCES OF SHOWERS AND STORMS FROM NW TO
SE...BUT I LEFT LOW CHANCES OF SHOWERS AND STORMS ACROSS MOST OF
THE FORECAST AREA SINCE A SHORTWAVE WILL LIKELY MOVE INTO THE
NORTHERN FORECAST AREA LATE TONIGHT. THIS SHORTWAVE COULD HELP
DEVELOP SOME MORE SHOWERS AND STORMS.
LONG TERM.../FRIDAY - WEDNESDAY/
THE WEST-NORTHWEST FLOW OF COOLER AND DRIER AIR WILL BE
ESTABLISHED OVER THE FORECAST AREA BY FRIDAY MIDDAY. THERE WILL
BE SOME LINGERING SHOWERS LEFT OVER FRIDAY MORNING BEFORE ENDING
BY MIDDAY. THE WEST TO NORTHWEST FLOW WILL CONTINUE INTO SATURDAY
BUT A WEAK SHORTWAVE WILL CAUSE A POSSIBILITY OF SHOWERS ACROSS
THE REGION. THE RIDGE WILL MOVE EAST AND A RETURN FLOW OF MOISTURE
TO THE FORECAST AREA ON SUNDAY. THIS WILL CONTINUE INTO MIDWEEK
WITH WEAK SHORTWAVES PASSING THROUGH THE FLOW. THIS WILL KEEP A
CHANCE FOR PRECIP ACROSS THE FORECAST AREA FOR THE TIME PERIOD.
TEMPS WILL BE NEAR NORMAL THROUGH MOST OF THE WEEK.
AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS WILL BE COMMON AT ALL TAFS SITES THIS AFTERNOON
EXCEPT FOR MVFR-IFR CIGS IN THUNDERSTORMS AT INL. A LINE OF STRONG
TO SEVERE THUNDERSTORMS WILL DEVELOP ALONG THE INTERNATIONAL
BORDER LATE THIS AFTERNOON AND MOVE SOUTHEAST TONIGHT ACROSS THE
TAF SITES. CIGS/VSBYS MAY DROP TO MVFR-IFR WITH LIFR CIGS POSSIBLE
IN THUNDERSTORMS. CONDITIONS WILL IMPROVE AFTER THE LINE PASSES
LATE TONIGHT AT ALL SITES. ON FRIDAY...VFR CONDITIONS WILL BE
COMMON AT ALL SITES.
&&
.POINT TEMPS/POPS...
DLH 65 78 52 70 / 60 20 10 10
INL 61 75 46 69 / 70 20 10 10
BRD 69 81 55 75 / 60 20 10 10
HYR 71 83 53 75 / 60 30 10 10
ASX 68 78 52 69 / 60 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS JACKSON MS
412 PM CDT WED JUL 17 2013
.DISCUSSION...
...STRONG TO SEVERE STORMS POSSIBLE TOMORROW AFTN/ERLY EVE...
SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS SOUTH MS AND
PORTIONS OF NE LA AS AFTERNOON CONVECTIVE TEMPERATURES ARE BEING
REACHED IN THE LOW TO MID 90S. SHOWER/STORM COVERAGE IS NOT GREAT
ACROSS THE REGION, AS EXPECTED, WITH SYNOPTIC SUBSIDENCE PREVAILING
AS A RESULT OF H5 RIDGE INFLUENCE CENTERED OVER THE OHIO VALLEY.
ANOTHER NOTABLE FEATURE IS A DEVELOPING TUTT LOW AND ASSOCIATED S/WV
VORTICITY IMPULSES TRAPPED IN THE EASTERLY MID-LVL FLOW ON THE
SOUTHERN PERIPHERY OF THE LARGE H5 RIDGE ACROSS THE WRN GOM AND
SOUTHERN ATLANTIC SEABOARD. THIS TUTT WILL AID IN THE STORMS
TOMORROW.
CURRENT SHOWER AND THUNDERSTORM ACTIVITY WILL SLOWLY DIMINISH
THROUGH THE EARLY EVENING HOURS AS THE ATMOSPHERE DESTABILIZES BUT AN
OUTSIDE STRONG STORM MAY BE POSSIBLE IF MERGERS OCCUR. THE POTENTIAL
FOR STRONG STORMS ACROSS FAR EAST MS TONIGHT HAS BEEN DECREASING WITH
ACTIVITY REMAINING CONFINED IN GA THIS AFTN AND STRUGGLING FARTHER
WEST IN AL WITH A DIMINISHING CU FIELD. LOCAL WRF AND HRRR SUPPORT
THIS THINKING AND HAVE ADJUSTED POPS/WX FOR THE OVRNGT PERIOD
ACCORDINGLY.
AS TUTT LOW INFLUENCE INCREASES TOMORROW, A NOTABLE LOW-LVL
CONVERGENT WIND FIELD LOOKS TO DEVELOP, CREATING AN INITIAL
CONVECTIVE TRIGGERING MECHANISM. A MORE THAN SUPPORTIVE THERMO
ENVIRONMENT LOOKS TO BE IN PLACE WITH >3000 J/KG SBCAPE, 27-28C
VERTICAL TOTALS AND STEEP LOW-LVL LAPSE RATES WITH TOMORROW LIKELY
THE WARMEST OF THE WEEK AS READINGS CLIMB INTO THE MID 90S. IT`S
TOUGH TO PINPOINT WHAT AREA WILL BE MORE FAVORED FOR SCATTERED TO
NUMEROUS STORM DEVELOPMENT AS IT WILL DEPEND ON H5 INVERTED TROUGH
AXIS LOCATION AND SPEED. NAM AND SUBSEQUENT HI-RES OUTPUT BASED ON
ITS INITIAL CONDITIONS ARE A BIT FASTER THAN GFS AND DEPICT BEST
COVERAGE IN CENTRAL AND WEST AREAS WITH GFS A TOUCH SLOWER WITH
POTENTIAL GREATER COVERAGE IN THE EAST. HAVE BLENDED THE TWO (WHICH
IS MUCH HIGHER THAN MAV POPS SUGGEST AND FOLLOWED MUCH CLOSER TO MET
GUIDANCE FOR THURS AFTN PERIOD. GIVEN HIGH LAPSE RATES AND ADEQUATE
INSTABILITY, STRAIGHT LINE WINDS OF 60 MPH, HAIL, AND HEAVY
DOWNPOURS WILL BE LIKELY INVOF STRONGEST STORMS. STORM MOTION WILL
BE SLOW AS ATM COLUMN HAS LITTLE FLOW, FURTHER AIDING IN LOCALIZED
POTENTIAL FOR FLASH FLOODING. ACTIVITY WILL SLOWLY DIMINISH THROUGH
THE MID TO LATE LATE EVE AS THE MID-UPPER LOW TRAVERSES WEST ACROSS
THE SABINE RIVER.
FOR FRIDAY...ANOTHER ROUND OF DECENT COVERAGE OF SHOWERS AND STORMS
AS CONTINUED FAVORABLE LIFT AND INSTABILITY REMAIN IN THE AREA WITH
THE TUTT LOW OVER ERN TX. SOME STORMS DURING FRI AFTN COULD AT LEAST
BE ON THE STRONG SIDE AND WILL HAVE TO MONITOR MESOSCALE EVOLUTION
THURSDAY TO SEE IF SEVERE STORMS COULD BE ATTAINED FRIDAY. HAVE
ADDED WORDING TO THE HWO/GRAPHICS FOR FRIDAY AFTN FOR THIS STRONG
STORM POTENTIAL.
FOR FORECAST ELEMENTS...MET POPS WERE USED AS A STARTING POINT FOR
TOMORROW IN LIEU OF LOW MAV POPS. POPS WERE ALSO BOOSTED FRIDAY WITH
WEAKNESS IN THE RIDGE AND TUTT LOW INFLUENCE. MAV LOW TEMPS WERE
BUMPED UP 1-3F DEGREES WITH HIGHS BUMPED DOWN 2F DEGREES BASED ON
RECENT TRENDS. /ALLEN/
&&
.AVIATION...VFR CONDS TO PERSIST THRU THE REST OF TODAY AND INTO
TONIGHT...ACCOMPANIED BY ELY/SELY SFC WINDS. ISOLD/SCT SHRA/TSRA WL
PERSIST ACROSS S/SW MS AND PORTIONS OF NE LA THIS AFTN BEFORE WANING
THIS EVENING. ISOLD SHRA/TSRA WL BE PSBL ACROSS ERN MS LATE THIS
AFTN/EVENING WHERE A FEW CELLS COULD MOVE INTO MS FROM OVER AL.
QUIET CONDS TO PREVAIL AREAWIDE BY 02Z...CONTINUING OVRNGT. PATCHY
MVFR VSBY WL BE PSBL 09-13Z TOMORROW. /BK/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 71 93 72 93 / 10 39 21 39
MERIDIAN 71 93 72 93 / 20 30 21 38
VICKSBURG 71 93 72 93 / 15 46 22 38
HATTIESBURG 71 93 73 93 / 14 42 21 44
NATCHEZ 71 91 72 91 / 16 46 21 48
GREENVILLE 73 95 74 94 / 10 46 20 37
GREENWOOD 71 94 72 94 / 10 30 17 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
ALLEN/BK
AREA FORECAST DISCUSSION
NWS GLASGOW MT
859 PM MDT THU JUL 18 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
EVENING UPDATE...
SHOWERS AND THUNDERSTORMS CROSSING THE INTERNATIONAL BORDER HAVE
FALLEN APART WITH THE EXIT OF PEAK HEATING. COLD FRONT PASSAGE
THIS EVENING IS EVIDENT ON RADAR AS A THIN LINE AND SHOULD BRING SOME
CAA DIRECTLY BEHIND. CURRENTLY A COUNTY LENGTH GRADIENT OF ABOUT 10
DEGREES FAHRENHEIT EXIST ALONG THE FRONT. THE FRONT ITSELF IS
EXPECTED TO STALL ALONG THE SOUTHERN AND WESTERN SECTIONS OF THE
CWA ALLOWING THE NORTH AND EAST TO COOL MORE THAN PREVIOUSLY
ANTICIPATED. WITH CLOUD COVER DISSIPATING FOR THE EVENING ALONG
WITH CAA HAVE DROPPED TEMPERATURES DOWN... AND AM USING THE NAMDNG5
BIAS CORRECTED GRIDS FOR OVERNIGHT LOWS AS IT SEEMS TO PICK UP ON
TERRAIN AND HAVE THE ORIENTATION OF THE FRONT CORRECT ACROSS THE
NORTHEAST. POPS FROM MIDNIGHT TO NOON WERE ALSO LOWERED OR
STRIPPED OUT WITH THE CLEARING SKIES. FINALLY... MESOSCALE MODELS
WERE MODDED INTO THE WIND GRIDS TO ACCOUNT FOR LIGHT VALLEY WINDS
OVER NIGHT. GAH
PREVIOUS SHORT TERM DISCUSSION...
500PM UPDATE...
CURRENT RADAR OBSERVATIONS SHOW SHOWERS AND THUNDERSTORMS ACROSS
SOUTHERN SASKATCHEWAN APPROACHING THE BORDER WITH PHILLIPS
COUNTY. PREVIOUS FORECAST CONFINED POPS TO THE NORTHEASTERN CORNER
OF THE CWA. GIVEN RECENT TRENDS...DECIDED TO EXTEND ISOLATED TO
LOW END SCATTERED POPS FURTHER WEST TO BE MORE IN LINE WITH NEAR
TERM EXPECTATIONS. DO EXPECT AS THE SUN SETS THAT CONVECTIVE
ACTIVITY WILL WANE...BUT DID INSERT ISOLATED MENTION IN THE
NORTHEAST WHERE A LINGERING SHOWER OVERNIGHT CANNOT BE RULED OUT.
TWEAKED SKY COVER AS WELL WITH CU FIELD ACROSS THE NORTH. MALIAWCO
A VERY WELL MIXED BOUNDARY LAYER THIS AFTERNOON AND EVENING HAS
BEEN LEADING TO GUSTY NORTHWEST WINDS ACROSS THE CWA. NOTICED THAT
SOME GUSTS HAVE BEEN APPROACHING 40 MPH AT TIMES. THEREFORE THE
GOING LAKE WIND ADVISORY LOOKS GOOD. WINDS ARE EXPECTED TO SUBSIDE
THIS EVENING...ESPECIALLY AROUND OR AFTER SUNSET. AT THAT TIME THE
NEXT SHIFT CAN HAVE A LOOK AT DETERMINING WHETHER OR NOT THE
HEADLINES CAN BE DROPPED A LITTLE EARLY. FOR NOW...WILL LEAVE IT
TO EXPIRE AT MIDNIGHT. DEEP VERTICAL MIXING HAS ALSO LED TO
TEMPERATURES SOARING INTO THE MIDDLE AND UPPER 80S ACROSS THE
FORECAST AREA WITH A FEW LOCATIONS TOPPING 90. SOME LOCATIONS WERE
EVEN A TAD WARMER THAN EXPECTED. CUMULUS FIELD EVIDENT ON THE
VISIBLE SATELLITE IMAGERY PUSHING INTO THE NORTHERN ZONES FROM
SOUTHERN SASKATCHEWAN. DO EXPECT THAT WHILE THE UPPER SHORT WAVE
MAY CLIP THE NORTHEASTERN ZONES THAT MUCH OF THE UPPER LEVEL
ENERGY WILL REMAIN NORTH AND EAST OF THE CWA. FELT THAT IT WAS
OKAY TO LEAVE IN SLIGHT CHANCE POPS FOR THE AFTERNOON AND EVENING
HOWEVER. LATEST HRRR MODEL DOES INDICATE POTENTIAL FOR AN ISOLATED
SHOWER OR THUNDERSTORM ACROSS PERHAPS DANIELS OR SHERIDAN COUNTY
RIGHT AROUND OR JUST AFTER 00Z.
FRIDAY AND SATURDAY...18/12Z MODEL GUIDANCE CONTINUES TO LEAVE
NORTHEAST MONTANA UNDER A REGIME OF NORTHWEST FLOW ALOFT.
SHORTWAVE ENERGY PROPAGATING THROUGH THE FLOW WILL BRING ABOUT
PERIODIC OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS... AS IT
RIDES OVER THE TOP OF A BACKDOOR COLD FRONT THAT IS EXPECTED TO
STALL OUT ACROSS THE CWA. MOISTURE IS EXPECTED TO BE QUITE
LIMITED. THEREFORE KEPT SLIGHT CHANCE TO LOW END CHANCE POPS GOING
FOR NOW...ESPECIALLY IN THE NORTHERN AND EASTERN PORTIONS OF THE
CWA. TEMPERATURES LOOK TO BE FAIRLY SEASONABLE WITH 850MB
TEMPERATURES EXHIBITING A SHARP GRADIENT WITH WARMER TEMPERATURES
ACROSS THE SOUTHWEST AND COOLER IN THE NORTHEAST. WITH THE
FORECAST REGION REMAINING ON THE NORTHEAST PERIPHERY OF THE UPPER
RIDGE ACROSS THE SOUTHWESTERN U.S. HOWEVER...DO NOT EXPECT ANY
MAJOR TRENDS IN TEMPERATURES THROUGH EARLY IN THE WEEKEND. MINOR
FLUCTUATIONS DAY TO DAY ARE POSSIBLE...BUT PERSISTENCE MAY BE A
NICE BASELINE TO START FROM FOR THE FORECAST FOR AT LEAST THE NEXT
COUPLE OF DAYS. WITH ANTICIPATED 850MB TEMPERATURE PATTERN...FULL
MIXING WOULD PROBABLY ENABLE HIGHS AROUND 90 IN PETROLEUM
COUNTY...RANGING TO CLOSER TO 80 IN SHERIDAN COUNTY FURTHER
NORTHEAST. LOW TEMPERATURES EACH MORNING MAY RANGE IN THE UPPER
50S TO LOW 60S. MALIAWCO
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
MAIN CHANGE WAS ADD MENTION OF THUNDERSTORMS FOR LATE MONDAY. ECMWF
REMAINS CONSISTENT WITH A DECENT VORT MAX MOVING EAST INTO MONTANA
AND DECENT INSTABILITY IN PLACE. CURRENT HWO DOES NOT MENTION
SEVERE THUNDERSTORM POSSIBILITY BUT LATER SHIFTS MAY HAVE TO ADD
THIS MENTION IF OTHER MODELS START TO LEAN IN THIS DIRECTION.
REST OF FORECAST MAINLY UNCHANGED. TFJ
PREVIOUS DISCUSSION...
BOTH THE ECMWF AND THE GFS MAINTAIN A WNW FLOW ALOFT IN TONIGHT/S
00Z MODEL RUNS THROUGH THE PERIOD. HOWEVER...THERE HAS BEEN RUN TO
RUN DIFFERENCES AND DIFFERENCES IN TIMING SHORTWAVES WITHIN THE
FLOW ALOFT. GENERALLY...MONTANA WILL BE ON PERIPHERY OF WESTERN
U.S. UPPER RIDGE.
AT THIS POINT...BOTH GFS AND ECMWF POINT TOWARDS SUNDAY AND MONDAY
BEING WARM AND MAINLY DRY WITH A SHORTWAVE RIDGE. MONDAY NIGHT AND
TUESDAY...ECMWF IS STRONGER AND SOMEWHAT FASTER WITH A COLD FRONT.
EITHER WAY...IT LOOKS LIKE LIMITED MOISTURE SO WILL MAINTAIN DRY
FORECAST FOR NOW AND KEEP TEMPERATURES CLOSE TO INHERITED FORECAST.
WEDNESDAY AND THURSDAY...WNW FLOW ALOFT CONTINUES WITH MODELS
TIMING SYSTEMS DIFFERENTLY. THEY GENERALLY KEEP THE AREA DRY WITH
TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL. FORRESTER
&&
.AVIATION...
VFR. NORTHWEST WINDS WILL SIGNIFICANTLY DIMINISH THIS EVENING
ABOUT 03Z TO LIGHT SPEEDS. NW WINDS WILL PICK UP AGAIN FRIDAY
AFTERNOON BUT NOT NEARLY AS STRONG AS TODAY. A BACKDOOR COLD FRONT
WILL KEEP MOST VFR CLOUDS TO THE NORTH AND EAST OF THE TERMINALS
LATER FRIDAY. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
515 PM MDT THU JUL 18 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
500PM UPDATE...
CURRENT RADAR OBSERVATIONS SHOW SHOWERS AND THUNDERSTORMS ACROSS
SOUTHERN SASKATCHEWAN APPROACHING THE BORDER WITH PHILLIPS
COUNTY. PREVIOUS FORECAST CONFINED POPS TO THE NORTHEASTERN CORNER
OF THE CWA. GIVEN RECENT TRENDS...DECIDED TO EXTEND ISOLATED TO
LOW END SCATTERED POPS FURTHER WEST TO BE MORE IN LINE WITH NEAR
TERM EXPECTATIONS. DO EXPECT AS THE SUN SETS THAT CONVECTIVE
ACTIVITY WILL WANE...BUT DID INSERT ISOLATED MENTION IN THE
NORTHEAST WHERE A LINGERING SHOWER OVERNIGHT CANNOT BE RULED OUT.
TWEAKED SKY COVER AS WELL WITH CU FIELD ACROSS THE NORTH. MALIAWCO
PREVIOUS SHORT TERM DISCUSSION...
A VERY WELL MIXED BOUNDARY LAYER THIS AFTERNOON AND EVENING HAS
BEEN LEADING TO GUSTY NORTHWEST WINDS ACROSS THE CWA. NOTICED THAT
SOME GUSTS HAVE BEEN APPROACHING 40 MPH AT TIMES. THEREFORE THE
GOING LAKE WIND ADVISORY LOOKS GOOD. WINDS ARE EXPECTED TO SUBSIDE
THIS EVENING...ESPECIALLY AROUND OR AFTER SUNSET. AT THAT TIME THE
NEXT SHIFT CAN HAVE A LOOK AT DETERMINING WHETHER OR NOT THE
HEADLINES CAN BE DROPPED A LITTLE EARLY. FOR NOW...WILL LEAVE IT
TO EXPIRE AT MIDNIGHT. DEEP VERTICAL MIXING HAS ALSO LED TO
TEMPERATURES SOARING INTO THE MIDDLE AND UPPER 80S ACROSS THE
FORECAST AREA WITH A FEW LOCATIONS TOPPING 90. SOME LOCATIONS WERE
EVEN A TAD WARMER THAN EXPECTED. CUMULUS FIELD EVIDENT ON THE
VISIBLE SATELLITE IMAGERY PUSHING INTO THE NORTHERN ZONES FROM
SOUTHERN SASKATCHEWAN. DO EXPECT THAT WHILE THE UPPER SHORT WAVE
MAY CLIP THE NORTHEASTERN ZONES THAT MUCH OF THE UPPER LEVEL
ENERGY WILL REMAIN NORTH AND EAST OF THE CWA. FELT THAT IT WAS
OKAY TO LEAVE IN SLIGHT CHANCE POPS FOR THE AFTERNOON AND EVENING
HOWEVER. LATEST HRRR MODEL DOES INDICATE POTENTIAL FOR AN ISOLATED
SHOWER OR THUNDERSTORM ACROSS PERHAPS DANIELS OR SHERIDAN COUNTY
RIGHT AROUND OR JUST AFTER 00Z.
FRIDAY AND SATURDAY...18/12Z MODEL GUIDANCE CONTINUES TO LEAVE
NORTHEAST MONTANA UNDER A REGIME OF NORTHWEST FLOW ALOFT.
SHORTWAVE ENERGY PROPAGATING THROUGH THE FLOW WILL BRING ABOUT
PERIODIC OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS... AS IT
RIDES OVER THE TOP OF A BACKDOOR COLD FRONT THAT IS EXPECTED TO
STALL OUT ACROSS THE CWA. MOISTURE IS EXPECTED TO BE QUITE
LIMITED. THEREFORE KEPT SLIGHT CHANCE TO LOW END CHANCE POPS GOING
FOR NOW...ESPECIALLY IN THE NORTHERN AND EASTERN PORTIONS OF THE
CWA. TEMPERATURES LOOK TO BE FAIRLY SEASONABLE WITH 850MB
TEMPERATURES EXHIBITING A SHARP GRADIENT WITH WARMER TEMPERATURES
ACROSS THE SOUTHWEST AND COOLER IN THE NORTHEAST. WITH THE
FORECAST REGION REMAINING ON THE NORTHEAST PERIPHERY OF THE UPPER
RIDGE ACROSS THE SOUTHWESTERN U.S. HOWEVER...DO NOT EXPECT ANY
MAJOR TRENDS IN TEMPERATURES THROUGH EARLY IN THE WEEKEND. MINOR
FLUCTUATIONS DAY TO DAY ARE POSSIBLE...BUT PERSISTENCE MAY BE A
NICE BASELINE TO START FROM FOR THE FORECAST FOR AT LEAST THE NEXT
COUPLE OF DAYS. WITH ANTICIPATED 850MB TEMPERATURE PATTERN...FULL
MIXING WOULD PROBABLY ENABLE HIGHS AROUND 90 IN PETROLEUM
COUNTY...RANGING TO CLOSER TO 80 IN SHERIDAN COUNTY FURTHER
NORTHEAST. LOW TEMPERATURES EACH MORNING MAY RANGE IN THE UPPER
50S TO LOW 60S. MALIAWCO
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
MAIN CHANGE WAS ADD MENTION OF THUNDERSTORMS FOR LATE MONDAY. ECMWF
REMAINS CONSISTENT WITH A DECENT VORT MAX MOVING EAST INTO MONTANA
AND DECENT INSTABILITY IN PLACE. CURRENT HWO DOES NOT MENTION
SEVERE THUNDERSTORM POSSIBILITY BUT LATER SHIFTS MAY HAVE TO ADD
THIS MENTION IF OTHER MODELS START TO LEAN IN THIS DIRECTION.
REST OF FORECAST MAINLY UNCHANGED. TFJ
PREVIOUS DISCUSSION...
BOTH THE ECMWF AND THE GFS MAINTAIN A WNW FLOW ALOFT IN TONIGHT/S
00Z MODEL RUNS THROUGH THE PERIOD. HOWEVER...THERE HAS BEEN RUN TO
RUN DIFFERENCES AND DIFFERENCES IN TIMING SHORTWAVES WITHIN THE
FLOW ALOFT. GENERALLY...MONTANA WILL BE ON PERIPHERY OF WESTERN
U.S. UPPER RIDGE.
AT THIS POINT...BOTH GFS AND ECMWF POINT TOWARDS SUNDAY AND MONDAY
BEING WARM AND MAINLY DRY WITH A SHORTWAVE RIDGE. MONDAY NIGHT AND
TUESDAY...ECMWF IS STRONGER AND SOMEWHAT FASTER WITH A COLD FRONT.
EITHER WAY...IT LOOKS LIKE LIMITED MOISTURE SO WILL MAINTAIN DRY
FORECAST FOR NOW AND KEEP TEMPERATURES CLOSE TO INHERITED FORECAST.
WEDNESDAY AND THURSDAY...WNW FLOW ALOFT CONTINUES WITH MODELS
TIMING SYSTEMS DIFFERENTLY. THEY GENERALLY KEEP THE AREA DRY WITH
TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL. FORRESTER
&&
.AVIATION...
VFR. NORTHWEST WINDS WILL SIGNIFICANTLY DIMINISH THIS EVENING
ABOUT 03Z TO LIGHT SPEEDS. NW WINDS WILL PICK UP AGAIN FRIDAY
AFTERNOON BUT NOT NEARLY AS STRONG AS TODAY. A BACKDOOR COLD FRONT
WILL KEEP MOST VFR CLOUDS TO THE NORTH AND EAST OF THE TERMINALS
LATER FRIDAY. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR FORT PECK LAKE
FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...CORRECTED
NWS GLASGOW MT
332 PM MDT WED JUL 17 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
MAIN CHALLENGE THIS AFTERNOON AND EVENING IS THE HIGH TEMPERATURE
FORECAST ACROSS THE CWA. ACROSS THE NORTHEAST...DECIDED TO LOWER
TEMPERATURES BY SEVERAL DEGREES BELOW 17/12Z GUIDANCE GIVEN THE
PERSISTENT STEADY SHOWERS AND CLOUD COVER THERE. ACROSS CENTRAL
PORTIONS OF THE CWA...AREAS SHOULD START TO SEE BREAKS OF SUNSHINE
WHICH WILL RESULT IN TEMPERATURES RESPONDING. DID LOWER HIGHS IN A
FEW LOCATIONS AS THERE ARE ONLY A FEW HOURS OF DAYTIME HEATING
REMAINING. IN SHORT...EXPECT 80 DEGREES OR BETTER LATE AFTERNOON
OR EVENING ACROSS THE SOUTHERN ZONES. TEMPERATURES SHOULD MAKE IT
TO THE LOWER TO MIDDLE 70S ACROSS CENTRAL PORTIONS OF THE FORECAST
AREA. ONLY EXPECT HIGHS TO REACH UPPER 60S AND NEAR 70 ACROSS THE
INTERNATIONAL BORDER AND IN THE FAR NORTHEAST.
TONIGHT...TRICKY FORECAST REGARDING POTENTIAL SHOWER ACTIVITY
DEVELOPING...PRIMARILY SOUTH OF THE MISSOURI RIVER. WILL INSERT
LOW END CHANCE POPS FOR NOW BUT THE NEXT SHIFT WILL HAVE TO
MONITOR FAIRLY CAREFULLY FOR UPDATES. THE LATEST GFS/ECMWF MODELS
ARE DRY BUT THE NAM AND HRRR SHOWS POTENTIAL FOR PRECIPITATION
TONIGHT ACROSS THE SOUTH. GIVEN MORE SUNSHINE DURING THE DAYTIME
ACROSS THOSE LOCATIONS THERE COULD BE A BIT MORE INSTABILITY TO
TAP AS WEAK SHORTWAVE ENERGY PUSHES THROUGH OVERNIGHT. GIVEN LACK
OF CONFIDENCE HOWEVER...DID NOT GO TOO AGGRESSIVE AT THIS TIME.
THURSDAY...UPPER LEVEL ZONAL FLOW IN THE MORNING WILL TRANSITION
TO NORTHWEST FLOW ALOFT AS A SHORTWAVE TRAVELING ACROSS THE
INTERNATIONAL BORDER CLIPS THE NORTHEASTERN ZONES AND SWEEPS A
SURFACE COLD FRONT THROUGH THE CWA. WILL EXPECT STRONG GUSTY WINDS
TO DEVELOP BEHIND THE FRONTAL PASSAGE. NAM BUFKIT SOUNDINGS
INDICATE 40 KTS IN THE MID LEVELS. GIVEN VERY GOOD LOW AND MID
LEVEL LAPSE RATES...SOME OF THESE GUSTS MAY MIX DOWN TO THE
SURFACE. EXPECT 20-25 MPH SUSTAINED WINDS WITH GUSTS TO 35 MPH TO
BE QUITE POSSIBLE...WITH ISOLATED HIGHER GUSTS. THEREFORE...WILL
HOIST A LAKE WIND ADVISORY BEGINNING AT 15Z AND HAVE IT EXPIRE AT
MIDNIGHT WHEN WINDS ARE EXPECTED TO RELAX. MAINTAINED CHANCE POPS
IN THE NORTHEAST CLOSER TO THE WAVE AND THE AREA OF BEST PVA.
DESPITE THE FRONTAL PASSAGE...HIGHS MAY PROVE TO BE WARMER ACROSS
THE NORTHEAST DUE TO MORE IN THE WAY OF SUNSHINE.
THURSDAY NIGHT AND FRIDAY...NORTHWEST FLOW ALOFT WILL CONTINUE
ACROSS THE FORECAST REGION AND SHORTWAVE ENERGY WILL PROPAGATE
THROUGH ON FRIDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND
POSSIBLY THUNDER IN THE NORTHEAST. IT SHOULD REMAIN FAIRLY DRY
THURSDAY NIGHT AND FRIDAY ACROSS A ROBUST PORTION OF THE FORECAST
AREA HOWEVER AS THE CWA IS EXPECTED TO SIT ON THE EXTREME
NORTHEAST PERIPHERY OF A RIDE DOMINATING THE SOUTHWESTERN STATES.
THE ONLY AREA OF CONCERN WILL BE THE NORTHEAST CORNER OF THE
FORECAST AREA WHERE SHORTWAVE ENERGY RIDING AROUND THE RIDGE MAY
LEAD TO ENHANCED VERTICAL ASCENT AND TRIGGER A FEW SHOWERS AND/OR
THUNDERSTORMS. THIS IS STILL A COUPLE OF DAYS OUT AND FUTURE
SHIFTS CAN EVALUATE POTENTIAL FURTHER. MALIAWCO
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
GOING FORECAST WAS IN GREAT SHAPE AND ONLY TWEAK MADE WAS TO
INCREASE POPS SLIGHTLY FOR MONDAY. JAMBA
PREVIOUS DISCUSSION...
BOTH THE EC AND THE GFS SHOW NORTHEAST MONTANA REMAINING UNDER A
NORTHWESTERLY FLOW ALOFT...AT LEAST THROUGH SUNDAY NIGHT...DUE TO
A PERSISTENT HEAT DOME OF HIGH PRESSURE CENTERED OVER THE GREAT
BASIN SUPPORTING A RIDGE IN THE WEST.
HOWEVER BEGINNING SUNDAY NIGHT THE 2 MODELS QUIT RESEMBLING EACH
OTHER. THE BIG DIFFERENCE IS THAT THE 12Z EC PICKS UP A COMPACT
CYCLONE OFF THE PACIFIC NORTHWEST COAST AND EJECTS IT ACROSS THE
INTER-MOUNTAIN WEST AND CANADIAN ROCKIES INTO ALBERTA AND
SASKATCHEWAN. THIS ACTION WOULD BACK FLOW ALOFT TO THE SOUTHWEST
AND SEND A COLD FRONT ACROSS THE DIVIDE TO REACH NEMONT AROUND
MONDAY NIGHT. THE GFS SHOWS NO HINT OF THIS WAVE. THEREFORE AFTER
THE WEEKEND THERE IS MORE UNCERTAINTY AS TO WHICH MODEL WILL PLAY
OUT. LATER IN THE SHIFT THE DELAYED 00Z EC STILL HOLDS ONTO THE
SHORTWAVE DISTURBANCE BUT RUNS IT EAST THROUGH MONTANA. WITH MORE
CONSISTENCY...REMAINED MOSTLY WITH THE GFS SOLUTION FOR THE REST
OF THE FORECAST.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...WITH HIGH PRESSURE TO THE
SOUTHWEST AND A STRONG CLOSED UPPER LOW ROTATING AROUND HUDSON
BAY...NORTHEAST MONTANA WILL HAVE THE STATIONARY COLD BOUNDARY TO
THE NORTHEAST AND DESERT AIR TRYING TO PUSH IN FROM THE SOUTH.
THIS PATTERN MIGHT SEE SOME OVERRUNNING MOISTURE NEAR THIS
BOUNDARY FIRING OFF A FEW THUNDERSTORMS. BUT FOR THE MOST
PART...DRY WARM AIR WILL BE THE MAIN FEATURE OF THE WEEKEND.
MONDAY AND BEYOND...WITH BOTH MODELS OUT OF PHASE WITH EACH
OTHER...WILL NOT MOVE MUCH ONE WAY OR THE OTHER FROM THE
INHERITED GRIDS. TEMPERATURE SHOULD BE VERY WARM ON MONDAY...AND
IF THE RIDGE HOLDS THE HIGHS WILL REMAIN VERY WARM. THE EC BRINGS
IN A FRONT AROUND MONDAY NIGHT WHICH WILL TEND TO COOL
TEMPERATURES AND ALSO BRING A BETTER CHANCE FOR STRONG
THUNDERSTORMS. SO FEW CHANGES MADE BEYOND MONDAY. SCT
&&
.AVIATION...
MVFR CONDITIONS WILL CONTINUE TO BE A POSSIBILITY ACROSS THE AREA
TONIGHT IN THE FORM OF LOW CLOUDS. PATCHY FOG MAY FORM IN A FEW
SPOTS AS WELL. CONDITIONS ARE EXPECTED TO QUICKLY IMPROVE THURSDAY
MORNING WITH A COLD FRONTAL PASSAGE. NORTHWEST WINDS BY THURSDAY
AFTERNOON WILL BE STRONG WITH SUSTAINED SPEEDS OF 20 TO 30 KTS
POSSIBLE. JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
259 PM MDT WED JUL 17 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
MAIN CHALLENGE THIS AFTERNOON AND EVENING IS THE HIGH TEMPERATURE
FORECAST ACROSS THE CWA. ACROSS THE NORTHEAST...DECIDED TO LOWER
TEMPERATURES BY SEVERAL DEGREES BELOW 17/12Z GUIDANCE GIVEN THE
PERSISTENT STEADY SHOWERS AND CLOUD COVER THERE. ACROSS CENTRAL
PORTIONS OF THE CWA...AREAS SHOULD START TO SEE BREAKS OF SUNSHINE
WHICH WILL RESULT IN TEMPERATURES RESPONDING. DID LOWER HIGHS IN A
FEW LOCATIONS AS THERE ARE ONLY A FEW HOURS OF DAYTIME HEATING
REMAINING. IN SHORT...EXPECT 80 DEGREES OR BETTER LATE AFTERNOON
OR EVENING ACROSS THE SOUTHERN ZONES. TEMPERATURES SHOULD MAKE IT
TO THE LOWER TO MIDDLE 70S ACROSS CENTRAL PORTIONS OF THE FORECAST
AREA. ONLY EXPECT HIGHS TO REACH UPPER 60S AND NEAR 70 ACROSS THE
INTERNATIONAL BORDER AND IN THE FAR NORTHEAST.
TONIGHT...TRICKY FORECAST REGARDING POTENTIAL SHOWER ACTIVITY
DEVELOPING...PRIMARILY SOUTH OF THE MISSOURI RIVER. WILL INSERT
LOW END SLIGHT CHANCE POPS FOR NOW BUT THE NEXT SHIFT WILL HAVE TO
MONITOR FAIRLY CAREFULLY FOR UPDATES. THE LATEST GFS/ECMWF MODELS
ARE DRY BUT THE NAM AND HRRR SHOWS POTENTIAL FOR PRECIPITATION
TONIGHT ACROSS THE SOUTH. GIVEN MORE SUNSHINE DURING THE DAYTIME
ACROSS THOSE LOCATIONS THERE COULD BE A BIT MORE INSTABILITY TO
TAP AS WEAK SHORTWAVE ENERGY PUSHES THROUGH OVERNIGHT. GIVEN LACK
OF CONFIDENCE HOWEVER...DID NOT GO TOO AGGRESSIVE AT THIS TIME.
THURSDAY...UPPER LEVEL ZONAL FLOW IN THE MORNING WILL TRANSITION
TO NORTHWEST FLOW ALOFT AS A SHORTWAVE TRAVELING ACROSS THE
INTERNATIONAL BORDER CLIPS THE NORTHEASTERN ZONES AND SWEEPS A
SURFACE COLD FRONT THROUGH THE CWA. WILL EXPECT STRONG GUSTY WINDS
TO DEVELOP BEHIND THE FRONTAL PASSAGE. NAM BUFKIT SOUNDINGS
INDICATE 40 KTS IN THE MID LEVELS. GIVEN VERY GOOD LOW AND MID
LEVEL LAPSE RATES...SOME OF THESE GUSTS MAY MIX DOWN TO THE
SURFACE. EXPECT 20-25 MPH SUSTAINED WINDS WITH GUSTS TO 35 MPH TO
BE QUITE POSSIBLE...WITH ISOLATED HIGHER GUSTS. THEREFORE...WILL
HOIST A LAKE WIND ADVISORY BEGINNING AT 15Z AND HAVE IT EXPIRE AT
MIDNIGHT WHEN WINDS ARE EXPECTED TO RELAX. MAINTAINED CHANCE POPS
IN THE NORTHEAST CLOSER TO THE WAVE AND THE AREA OF BEST PVA.
DESPITE THE FRONTAL PASSAGE...HIGHS MAY PROVE TO BE WARMER ACROSS
THE NORTHEAST DUE TO MORE IN THE WAY OF SUNSHINE.
THURSDAY NIGHT AND FRIDAY...NORTHWEST FLOW ALOFT WILL CONTINUE
ACROSS THE FORECAST REGION AND SHORTWAVE ENERGY WILL PROPAGATE
THROUGH ON FRIDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND
POSSIBLY THUNDER IN THE NORTHEAST. IT SHOULD REMAIN FAIRLY DRY
THURSDAY NIGHT AND FRIDAY ACROSS A ROBUST PORTION OF THE FORECAST
AREA HOWEVER AS THE CWA IS EXPECTED TO SIT ON THE EXTREME
NORTHEAST PERIPHERY OF A RIDE DOMINATING THE SOUTHWESTERN STATES.
THE ONLY AREA OF CONCERN WILL BE THE NORTHEAST CORNER OF THE
FORECAST AREA WHERE SHORTWAVE ENERGY RIDING AROUND THE RIDGE MAY
LEAD TO ENHANCED VERTICAL ASCENT AND TRIGGER A FEW SHOWERS AND/OR
THUNDERSTORMS. THIS IS STILL A COUPLE OF DAYS OUT AND FUTURE
SHIFTS CAN EVALUATE POTENTIAL FURTHER. MALIAWCO
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
GOING FORECAST WAS IN GREAT SHAPE AND ONLY TWEAK MADE WAS TO
INCREASE POPS SLIGHTLY FOR MONDAY. JAMBA
PREVIOUS DISCUSSION...
BOTH THE EC AND THE GFS SHOW NORTHEAST MONTANA REMAINING UNDER A
NORTHWESTERLY FLOW ALOFT...AT LEAST THROUGH SUNDAY NIGHT...DUE TO
A PERSISTENT HEAT DOME OF HIGH PRESSURE CENTERED OVER THE GREAT
BASIN SUPPORTING A RIDGE IN THE WEST.
HOWEVER BEGINNING SUNDAY NIGHT THE 2 MODELS QUIT RESEMBLING EACH
OTHER. THE BIG DIFFERENCE IS THAT THE 12Z EC PICKS UP A COMPACT
CYCLONE OFF THE PACIFIC NORTHWEST COAST AND EJECTS IT ACROSS THE
INTER-MOUNTAIN WEST AND CANADIAN ROCKIES INTO ALBERTA AND
SASKATCHEWAN. THIS ACTION WOULD BACK FLOW ALOFT TO THE SOUTHWEST
AND SEND A COLD FRONT ACROSS THE DIVIDE TO REACH NEMONT AROUND
MONDAY NIGHT. THE GFS SHOWS NO HINT OF THIS WAVE. THEREFORE AFTER
THE WEEKEND THERE IS MORE UNCERTAINTY AS TO WHICH MODEL WILL PLAY
OUT. LATER IN THE SHIFT THE DELAYED 00Z EC STILL HOLDS ONTO THE
SHORTWAVE DISTURBANCE BUT RUNS IT EAST THROUGH MONTANA. WITH MORE
CONSISTENCY...REMAINED MOSTLY WITH THE GFS SOLUTION FOR THE REST
OF THE FORECAST.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...WITH HIGH PRESSURE TO THE
SOUTHWEST AND A STRONG CLOSED UPPER LOW ROTATING AROUND HUDSON
BAY...NORTHEAST MONTANA WILL HAVE THE STATIONARY COLD BOUNDARY TO
THE NORTHEAST AND DESERT AIR TRYING TO PUSH IN FROM THE SOUTH.
THIS PATTERN MIGHT SEE SOME OVERRUNNING MOISTURE NEAR THIS
BOUNDARY FIRING OFF A FEW THUNDERSTORMS. BUT FOR THE MOST
PART...DRY WARM AIR WILL BE THE MAIN FEATURE OF THE WEEKEND.
MONDAY AND BEYOND...WITH BOTH MODELS OUT OF PHASE WITH EACH
OTHER...WILL NOT MOVE MUCH ONE WAY OR THE OTHER FROM THE
INHERITED GRIDS. TEMPERATURE SHOULD BE VERY WARM ON MONDAY...AND
IF THE RIDGE HOLDS THE HIGHS WILL REMAIN VERY WARM. THE EC BRINGS
IN A FRONT AROUND MONDAY NIGHT WHICH WILL TEND TO COOL
TEMPERATURES AND ALSO BRING A BETTER CHANCE FOR STRONG
THUNDERSTORMS. SO FEW CHANGES MADE BEYOND MONDAY. SCT
&&
.AVIATION...
MVFR CONDITIONS WILL CONTINUE TO BE A POSSIBILITY ACROSS THE AREA
TONIGHT IN THE FORM OF LOW CLOUDS. PATCHY FOG MAY FORM IN A FEW
SPOTS AS WELL. CONDITIONS ARE EXPECTED TO QUICKLY IMPROVE THURSDAY
MORNING WITH A COLD FRONTAL PASSAGE. NORTHWEST WINDS BY THURSDAY
AFTERNOON WILL BE STRONG WITH SUSTAINED SPEEDS OF 20 TO 30 KTS
POSSIBLE. JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
914 AM MDT WED JUL 17 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
900AM UPDATE...
NUMEROUS TO WIDESPREAD SHOWERS CONTINUE TO SPILL ACROSS THE CWA
FROM SOUTHWEST TO NORTHEAST. THEY ARE HOLDING TOGETHER RATHER WELL
AND SO INCREASED POPS FURTHER FOR THE NEXT FEW HOURS. THE HRRR
CONTINUES TO INDICATE THAT THEY WILL MOVE INTO THE NORTHEASTERN
ZONES LATER THIS MORNING AND THIS AFTERNOON AND SO INCLUDED
SCATTERED SHOWERS FOR THOSE LOCATIONS AS WELL. WILL MAINTAIN
ISOLATED MENTION OF THUNDER FOR NOW. OTHER CHANGES INCLUDED TWEAKS
TO TEMPERATURES AND SKY COVER. HIGH TEMPERATURES MAY WIND UP BEING
A DEGREE OR TWO COOLER THAN FORECAST IF SHOWERS AND HEAVY CLOUD
COVER PERSIST. CONCERNS CONTINUE FOR POTENTIAL LAKE WIND ADVISORY
FOR TOMORROW. WILL PUT MORE FOCUS ON THAT WITH THE AFTERNOON
PACKAGE. MALIAWCO
800AM UPDATE...
RAN A QUICK UPDATE AS A BAND OF SHOWERS AND POSSIBLY AN ISOLATED
THUNDERSTORM WERE MOVING NORTHEAST INTO PETROLEUM AND PHILLIPS
COUNTY. WITH A VERY MOIST ATMOSPHERE IN PLACE...THESE WILL AFFECT
THE NW TWO-THIRDS OF THE CWA WITH AMOUNTS OF A TENTH OF AN INCH IN
PLACES. 11Z HRRR MODEL SEEMED TO CAPTURE THIS FEATURE BEST. JAMBA
PREVIOUS DISCUSSION...
A SHORTWAVE TROUGH CURRENTLY OVER SW MONTANA WILL MOVE THROUGH
EASTERN MONTANA TODAY ON SW FLOW ALOFT. THIS WAVE HAS SOME SHOWERS
AND ISOLATED THUNDERSTORMS WITH IT AT 08Z. AT THIS POINT...SOME
THE MODELS ARE HAVING TROUBLE BRINGING THE PRECIP NORTHEAST WITH
THE WAVE WHICH LOOKS UNREASONABLE WITH PRECIPITABLE WATER AROUND
1.6 INCHES. AT THE SAME TIME...A WARM FRONT WILL MOVE NORTH FROM
WYOMING INTO SOUTHERN MONTANA. THE WAVE AND FRONT SHOULD BE ABLE
TRIGGER A FEW SHOWERS AND THUNDERSTORMS SOMEWHERE IN THE FORECAST
AREA TODAY.
TONIGHT...A SURFACE LOW DEVELOPS OVER EASTERN MONTANA WITH THE
WARM FRONT LIFTING NORTH. WILL MAINTAIN A CHANCE OF SHOWERS AND
THUNDERSTORMS.
BY THURSDAY...FLOW ALOFT TURNS ZONAL AHEAD OF A SHORTWAVE TROUGH
MOVING THROUGH ALBERTA IN THE MORNING. THEN THE WAVE CLIPS NE MT
IN THE AFTERNOON AS IT MOVES TOWARDS NORTH DAKOTA. THIS WILL BRING
A COLD FRONT THROUGH THE AREA IN THE MORNING WITH NORTHWEST WINDS
DEVELOPING BEHIND THE FRONT. WIND SPEEDS SHOULD REACH LAKE WIND
ADVISORY CRITERIA (20 MPH) BY AFTERNOON. SHOWERS AND THUNDERSTORMS
REMAIN A POSSIBILITY WITH THE WAVE AND FRONT.
FLOW ALOFT TURNS TO THE NORTHWEST THURSDAY NIGHT AND REMAINS THAT
WAY FOR FRIDAY. IT WILL BE DRY FOR THE MOST PART BUT A SHORTWAVE
FRIDAY COULD BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
NORTHEAST HALF OF THE FORECAST AREA. FORRESTER
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
BOTH THE EC AND THE GFS SHOW NORTHEAST MONTANA REMAINING UNDER A
NORTHWESTERLY FLOW ALOFT...AT LEAST THROUGH SUNDAY NIGHT...DUE TO
A PERSISTENT HEAT DOME OF HIGH PRESSURE CENTERED OVER THE GREAT
BASIN SUPPORTING A RIDGE IN THE WEST.
HOWEVER BEGINNING SUNDAY NIGHT THE 2 MODELS QUIT RESEMBLING EACH
OTHER. THE BIG DIFFERENCE IS THAT THE 12Z EC PICKS UP A COMPACT
CYCLONE OFF THE PACIFIC NORTHWEST COAST AND EJECTS IT ACROSS THE
INTER-MOUNTAIN WEST AND CANADIAN ROCKIES INTO ALBERTA AND
SASKATCHEWAN. THIS ACTION WOULD BACK FLOW ALOFT TO THE SOUTHWEST
AND SEND A COLD FRONT ACROSS THE DIVIDE TO REACH NEMONT AROUND
MONDAY NIGHT. THE GFS SHOWS NO HINT OF THIS WAVE. THEREFORE AFTER
THE WEEKEND THERE IS MORE UNCERTAINTY AS TO WHICH MODEL WILL PLAY
OUT. LATER IN THE SHIFT THE DELAYED 00Z EC STILL HOLDS ONTO THE
SHORTWAVE DISTURBANCE BUT RUNS IT EAST THROUGH MONTANA. WITH MORE
CONSISTENCY...REMAINED MOSTLY WITH THE GFS SOLUTION FOR THE REST
OF THE FORECAST.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...WITH HIGH PRESSURE TO THE
SOUTHWEST AND A STRONG CLOSED UPPER LOW ROTATING AROUND HUDSON
BAY...NORTHEAST MONTANA WILL HAVE THE STATIONARY COLD BOUNDARY TO
THE NORTHEAST AND DESERT AIR TRYING TO PUSH IN FROM THE SOUTH.
THIS PATTERN MIGHT SEE SOME OVERRUNNING MOISTURE NEAR THIS
BOUNDARY FIRING OFF A FEW THUNDERSTORMS. BUT FOR THE MOST
PART...DRY WARM AIR WILL BE THE MAIN FEATURE OF THE WEEKEND.
MONDAY AND BEYOND...WITH BOTH MODELS OUT OF PHASE WITH EACH
OTHER...WILL NOT MOVE MUCH ONE WAY OR THE OTHER FROM THE
INHERITED GRIDS. TEMPERATURE SHOULD BE VERY WARM ON MONDAY...AND
IF THE RIDGE HOLDS THE HIGHS WILL REMAIN VERY WARM. THE EC BRINGS
IN A FRONT AROUND MONDAY NIGHT WHICH WILL TEND TO COOL
TEMPERATURES AND ALSO BRING A BETTER CHANCE FOR STRONG
THUNDERSTORMS. SO FEW CHANGES MADE BEYOND MONDAY. SCT
&&
.AVIATION...
AN AREA OF SHOWERS WERE MOVING NORTHEAST INTO THE AREA THIS
MORNING. VISIBILITIES WERE PROBABLY DROPPING INTO THE MVFR RANGE
UNDER THE HEAVIEST SHOWERS WEST OF GLASGOW. CONDITIONS ARE
EXPECTED TO IMPROVE THIS AFTERNOON WITH THE SHOWERS MOVING TO THE
NORTH. A MODERATE EAST WIND IS THEN EXPECTED TO PICK UP IN IT/S
WAKE FOR LATER TODAY. JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
754 AM MDT WED JUL 17 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
RAN A QUICK UPDATE AS A BAND OF SHOWERS AND POSSIBLY AN ISOLATED
THUNDERSTORM WERE MOVING NORTHEAST INTO PETROLEUM AND PHILLIPS
COUNTY. WITH A VERY MOIST ATMOSPHERE IN PLACE...THESE WILL AFFECT
THE NW TWO-THIRDS OF THE CWA WITH AMOUNTS OF A TENTH OF AN INCH IN
PLACES. 11Z HRRR MODEL SEEMED TO CAPTURE THIS FEATURE BEST. JAMBA
PREVIOUS DISCUSSION...
A SHORTWAVE TROUGH CURRENTLY OVER SW MONTANA WILL MOVE THROUGH
EASTERN MONTANA TODAY ON SW FLOW ALOFT. THIS WAVE HAS SOME SHOWERS
AND ISOLATED THUNDERSTORMS WITH IT AT 08Z. AT THIS POINT...SOME
THE MODELS ARE HAVING TROUBLE BRINGING THE PRECIP NORTHEAST WITH
THE WAVE WHICH LOOKS UNREASONABLE WITH PRECIPITABLE WATER AROUND
1.6 INCHES. AT THE SAME TIME...A WARM FRONT WILL MOVE NORTH FROM
WYOMING INTO SOUTHERN MONTANA. THE WAVE AND FRONT SHOULD BE ABLE
TRIGGER A FEW SHOWERS AND THUNDERSTORMS SOMEWHERE IN THE FORECAST
AREA TODAY.
TONIGHT...A SURFACE LOW DEVELOPS OVER EASTERN MONTANA WITH THE
WARM FRONT LIFTING NORTH. WILL MAINTAIN A CHANCE OF SHOWERS AND
THUNDERSTORMS.
BY THURSDAY...FLOW ALOFT TURNS ZONAL AHEAD OF A SHORTWAVE TROUGH
MOVING THROUGH ALBERTA IN THE MORNING. THEN THE WAVE CLIPS NE MT
IN THE AFTERNOON AS IT MOVES TOWARDS NORTH DAKOTA. THIS WILL BRING
A COLD FRONT THROUGH THE AREA IN THE MORNING WITH NORTHWEST WINDS
DEVELOPING BEHIND THE FRONT. WIND SPEEDS SHOULD REACH LAKE WIND
ADVISORY CRITERIA (20 MPH) BY AFTERNOON. SHOWERS AND THUNDERSTORMS
REMAIN A POSSIBILITY WITH THE WAVE AND FRONT.
FLOW ALOFT TURNS TO THE NORTHWEST THURSDAY NIGHT AND REMAINS THAT
WAY FOR FRIDAY. IT WILL BE DRY FOR THE MOST PART BUT A SHORTWAVE
FRIDAY COULD BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
NORTHEAST HALF OF THE FORECAST AREA. FORRESTER
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
BOTH THE EC AND THE GFS SHOW NORTHEAST MONTANA REMAINING UNDER A
NORTHWESTERLY FLOW ALOFT...AT LEAST THROUGH SUNDAY NIGHT...DUE TO
A PERSISTENT HEAT DOME OF HIGH PRESSURE CENTERED OVER THE GREAT
BASIN SUPPORTING A RIDGE IN THE WEST.
HOWEVER BEGINNING SUNDAY NIGHT THE 2 MODELS QUIT RESEMBLING EACH
OTHER. THE BIG DIFFERENCE IS THAT THE 12Z EC PICKS UP A COMPACT
CYCLONE OFF THE PACIFIC NORTHWEST COAST AND EJECTS IT ACROSS THE
INTER-MOUNTAIN WEST AND CANADIAN ROCKIES INTO ALBERTA AND
SASKATCHEWAN. THIS ACTION WOULD BACK FLOW ALOFT TO THE SOUTHWEST
AND SEND A COLD FRONT ACROSS THE DIVIDE TO REACH NEMONT AROUND
MONDAY NIGHT. THE GFS SHOWS NO HINT OF THIS WAVE. THEREFORE AFTER
THE WEEKEND THERE IS MORE UNCERTAINTY AS TO WHICH MODEL WILL PLAY
OUT. LATER IN THE SHIFT THE DELAYED 00Z EC STILL HOLDS ONTO THE
SHORTWAVE DISTURBANCE BUT RUNS IT EAST THROUGH MONTANA. WITH MORE
CONSISTENCY...REMAINED MOSTLY WITH THE GFS SOLUTION FOR THE REST
OF THE FORECAST.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...WITH HIGH PRESSURE TO THE
SOUTHWEST AND A STRONG CLOSED UPPER LOW ROTATING AROUND HUDSON
BAY...NORTHEAST MONTANA WILL HAVE THE STATIONARY COLD BOUNDARY TO
THE NORTHEAST AND DESERT AIR TRYING TO PUSH IN FROM THE SOUTH.
THIS PATTERN MIGHT SEE SOME OVERRUNNING MOISTURE NEAR THIS
BOUNDARY FIRING OFF A FEW THUNDERSTORMS. BUT FOR THE MOST
PART...DRY WARM AIR WILL BE THE MAIN FEATURE OF THE WEEKEND.
MONDAY AND BEYOND...WITH BOTH MODELS OUT OF PHASE WITH EACH
OTHER...WILL NOT MOVE MUCH ONE WAY OR THE OTHER FROM THE
INHERITED GRIDS. TEMPERATURE SHOULD BE VERY WARM ON MONDAY...AND
IF THE RIDGE HOLDS THE HIGHS WILL REMAIN VERY WARM. THE EC BRINGS
IN A FRONT AROUND MONDAY NIGHT WHICH WILL TEND TO COOL
TEMPERATURES AND ALSO BRING A BETTER CHANCE FOR STRONG
THUNDERSTORMS. SO FEW CHANGES MADE BEYOND MONDAY. SCT
&&
.AVIATION...
A WEAK FRONTAL BOUNDARY AND OVERRUNNING MOISTURE IN THE SW WILL
CONTINUE TO PRODUCE ISOLATED TO SCATTERED RAIN SHOWERS AND GENERAL
THUNDERSTORMS TODAY. A WEAK SURFACE LOW IN THE LEE OF THE NORTHERN
ROCKIES WILL MAINTAIN A LIGHT TO MODERATE EASTERLY SURFACE BREEZE.
SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
339 PM EDT WED JUL 17 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
SATURDAY. SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD.
IN ADDITION...THE HOT AND HUMID WEATHER WILL CONTINUE UNTIL
SATURDAY...BEFORE MUCH DRIER AND COOLER AIR ARRIVES ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 250 PM EDT WEDNESDAY...SVR WATCH #416 CONTINUES UNTIL
MIDNIGHT FOR ENTIRE CWA. EXPECTING SEVERAL ROUNDS OF
STORMS...FIRST ACRS THE SLV/OTTAWA VALLEY AND NORTHERN NY BTWN 4PM
AND 6PM...THEN SECONDARY AND MORE POTENT LINE OF STORMS APPROACHES
NORTHERN ZNS BTWN 22-00Z THIS EVENING. THIS WL HAVE POTENTIAL FOR
A WELL ORGANIZED LINE OF STORMS WITH ENHANCED BOWING SEGMENTS
POSSIBLE. STILL THINKING THE PRIMARY THREAT WL BE STRONG/DAMAGING
WINDS...WITH ISOLATED/SCATTERED POWER OUTAGES/TREES DOWN. THINKING
LINE WL ENTER CPV BTWN 01-02Z...AND DISSIPATE BY 03Z ACRS OUR
EASTERN CWA. THE MAIN CONCENTRATION WL BE ACRS NORTHERN NY INTO
CENTRAL/NORTHERN VT.
FCST CHALLENGE WL BE TIMING OF THE CONVECTION WEAKENING/MOVING EAST
OF OUR CWA LATE THIS EVENING...FOLLOWED BY FOG POTENTIAL OVERNIGHT.
WATER VAPOR SHOWS POTENT S/W ENERGY ENTERING THE OTTAWA VALLEY
ATTM...WHICH WL CONT TO DEVELOP A LINE OF SVR STORMS ACRS OUR
CENTRAL/NORTHERN CWA THIS EVENING. THIS SYSTEM IS PROGGED TO BE EAST
OF CWA BY 06Z TONIGHT...WHICH COMBINED WITH LOSS OF DAYTIME
HEATING/INSTABILITY WL RESULT IN A DECREASE IN SHOWERS/STORMS. WL
MENTION CHC/LIKELY POPS THRU 03Z...ALONG WITH ENHANCED WORDING FOR
WINDS/HEAVY RAINFALL. RAP 13 SHOWS DEEP LAYER SHEAR VALUES BTWN 35
AND 40 KNOTS ACRS OUR NORTHERN CWA...ALONG WITH SFC BASED CAPE
AROUND 2000 J/KG...PERSISTING THRU THE EVENING HRS. THIS WL PROVIDE
ENOUGH INSTABILITY TO KEEP STORMS STRONG/SVR INTO THE EVENING
HOURS...WITH PRIMARY THREAT BEING DAMAGING WINDS. GIVEN...VERY WARM
DWPTS AND SOUTHERLY WINDS...EXPECT LOWS MAINLY IN THE M60S MTNS TO
L70S WARMER VALLEYS WITH PATCHY FOG POSSIBLE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 340 PM EDT WEDNESDAY...THE FCST CHALLENGE WL BE AREAL COVERAGE/INTENSITY
OF STORMS EACH AFTN/EVENING THRU FRI NIGHT. OVERALL...EXPECTING
AN ACTIVE COUPLE DAYS WITH SEVERAL ROUNDS OF STRONG TO POSSIBLY
SEVERE STORMS...ALONG WITH VERY HOT AND HUMID CONDITIONS...PERSISTING
THRU FRIDAY.
THURS INTO THURS NIGHT...A LITTLE MORE UNCERTAINTY ON PLACEMENT OF
ULVL SUPPORT...POSITION OF DEEPEST MOISTURE...AND ASSOCIATED SFC
BOUNDARY...ESPECIALLY GIVEN THIS EVENINGS CONVECTION. LATEST 12Z
GFS SHOWS BETTER DYNAMICS AND RH FIELDS...ALONG WITH THE
ASSOCIATED CONVECTION ACRS OUR SOUTHERN CWA...WHILE NAM12 SHOWS
POTENT 5H ENERGY AND GOOD RH ENTERING THE SLV BY 18Z AND MOVING INTO
THE CPV BY 21Z...AND THRU VT BY 03Z FRIDAY. BOTH NAM/GFS SHOW
FAVORABLE SHEAR/INSTABILITY PARAMETERS FOR ORGANIZED
CONVECTION...ALONG WITH A LEFTOVER SFC BOUNDARY/TRRN FOR LLVL
TRIGGER...BUT ULVL SUPPORT IS WEAKER. SOUNDING PROFILES SHOW CAPE
VALUES BTWN 2000 AND 2500 J/KG AND BEST 0 TO 6KM SHEAR OF 40 NEAR
NEAR THE INTERNATIONAL BORDER...CLOSEST TO THE MID LVL WIND MAX.
ONCE AGAIN...PRIMARY SVR WEATHER THREAT WL BE ISOLATED PULSE STRONG
AND DAMAGING WINDS. IN ADDITION...LOCAL 2KM AND 4KM ARE VERY ROBUST
WITH DEVELOPMENT OF COMPOSITE REFLECTIVITY FIELDS...BUT MAYBE A BIT
OVERDONE ON AREAL COVERAGE...BASED ON PREVIOUS EXPERIENCE. WL CONT
TO MENTION CHC POPS FROM 16Z THRU 03Z...THINKING ACTIVITY WL START
EARLIER ON THURS...BASED ON POSITION OF S/W ENERGY AND DISSIPATE BY
EARLY EVENING. PROGGED 85H AND 925MB TEMPS COOLER SLIGHTLY AND
SUPPORT HIGHS IN THE M80S MTNS TO L90S WARMER VALLEY
LOCATIONS...WITH VERY SIMILAR OVERNIGHT LOWS TO RECENT NIGHTS...M60S
TO L70S.
ON FRIDAY...MID/UPPER LVL TROF ACRS THE GREAT LAKES APPROACHES OUR
WESTERN CWA...ALONG WITH SEVERAL EMBEDDED S/W`S IN THE FAST
WEST/SOUTHWEST FLW ALOFT. THIS ENERGY/HGHT FALLS...COMBINED WITH
BETTER 850 TO 500MB RH PROFILES WL RESULT IN MORE AFTN/EVENING
SHOWERS/STORMS ON FRIDAY. NAM/GFS CONT TO SHOW BEST 0 TO 6 KM SHEAR
VALUES BTWN 40 AND 45 KNOTS ACRS OUR CENTRAL/NORTHERN CWA...ALONG
WITH CAPE VALUES AROUND 2000 J/KG. SO A FEW STRONG/SVR STORMS WL BE
POSSIBLE. SOME UNCERTAINTY ON OVERALL ORGANIZATION AND TIMING OF
INDIVIDUAL S/W`S IN FAST FLW ALOFT...ALONG WITH PLACEMENT OF
PRE-FRONTAL TROFS. SPC DAY 3 HIGHLIGHTS OUR CENTRAL/NORTHERN CWA IN
SLIGHT RISK. PWS BTWN 1.50 AND 2.0" SUPPORTS THE POTENTIAL FOR HEAVY
RAINFALL...BUT WITH STORM MOTION OF 20 TO 30 KNTS...NOT ANTICIPATING
ANY SIGNIFICANT HYDRO PROBLEMS. MAYBE SOME MINOR POOR DRAINAGE/URBAN
TYPE STUFF. PROGGED 85H TEMPS BTWN 16-18C AND 925MB TEMPS BTWN
22-24C...SUPPORT HIGHS ONCE AGAIN WELL INTO THE M/U 80S MTNS TO M90S
WARMER VALLEY LOCATIONS...ESPECIALLY SW DOWNSLOPE AREAS LIKE PBG.
HEAT INDEX VALUES WL ONCE AGAIN APPROACH 100 DEGREES IN A FEW
LOCATIONS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 310 PM EDT WEDNESDAY...COLD FRONT EXPECTED TO OPEN THE
EXTENDED PORTION OF THE FORECAST NEAR THE SAINT LAWRENCE VALLEY.
DUE TO THE UPPER-LEVEL GEOSTROPHIC FLOW ROUGHLY PARALLEL TO THE
ORIENTATION OF THE SFC FRONT...HAVE OPTED TO SLOW THE APPROACHING
COLD FRONT`S PROGRESSION THROUGH THE NORTH COUNTRY. THUS HAVE
MAINTAINED HIGH CHANCE TO LIKELY POPS ON SATURDAY...GRADUALLY
TAPERING TO SLIGHT CHANCE/CHANCE ON SATURDAY NIGHT. NOT QUITE THE
DEGREE OF INSTABILITY AS EXPECTED ON FRIDAY BUT PWATS STILL IN THE
1.5-2.0" RANGE SUGGEST THAT ANY STORMS COULD PRODUCE SOME LOCALLY
HEAVY RAIN. WENT WITH HIGHS IN THE UPPER 70S TO LOW/MID 80S BASED
ON EXPECTED CLOUD COVER AND PRE-FRONTAL 925 MB TEMPERATURES AROUND
18-21C...WENT WITH HIGHS IN THE UPPER 70S TO MID-80S.
A NOTICEABLY COOLER AND DRIER SUNDAY AND MONDAY IS EXPECTED AS
BROAD CANADIAN HIGH PRESSURE SETTLES INTO THE REGION. TEMPERATURES
RETURN CLOSER TO NORMAL/BELOW NORMAL FOR MID JULY. GIVEN ONGOING
ACTIVE WEATHER I DIDN`T LOOK TOO CLOSELY INTO NEXT WEEK...THOUGH IT
DOES APPEAR TO TURN MORE ACTIVE WEATHER-WISE WITH TEMPERATURES AND
HUMIDITY LEVELS BEGINNING TO REBOUND. THERFORE HAVE KEPT A TOKEN
SLIGHT CHANCE/CHANCE POPS GOING.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY...ACTIVE AVIATION FORECAST FOR THIS AFTERNOON
AND EVENING WITH POTENTIAL FOR LOCALLY STG THUNDERSTORMS.
THUNDERSTORMS ARE CURRENTLY DEVELOPING IN THE OTTAWA AND THE
WESTERN SAINT LAWRENCE VALLEYS MOVING EAST-SOUTHEASTWARD. VFR
CONDITIONS EXPECTED TO PREVAIL UNTIL THUNDERSTORMS APPROACH WITH
GENERAL TIMING BETWEEN 18-05Z. ACTIVITY TO BEGIN WITHIN THE NEXT
HOUR OR TWO AT MSS AND SLK...INTO PBG AND BTV AROUND 23-00Z AND
AFTER 01Z FOR RUT AND MPV. POTENTIAL FOR STRONG TO LOCALLY
DAMAGING WINDS AND ASSOCIATED LLVL TURBULENCE...BRIEF PERIOD OF
MVFR TO IFR VISIBILITIES...AND LIGHTNING WITH THUNDERSTORMS.
WINDS WILL BE SOUTH AROUND 5-9KTS. WILL TREAT WITH VCSH FOR NOW
AND USE TEMPOS ACCORDINGLY. THUNDERSTORM ACTIVITY LOOKS TO END
AFTER 05Z WITH FOG/MIST POTENTIAL TONIGHT GIVEN SATURATED LOW-
LEVELS AND LIGHT SFC WINDS TONIGHT. AREAS THAT RECEIVE RAIN TODAY
WILL STAND A GREATER CHANCE AT FOG/MIST TONIGHT...SO FOR NOW HAVE
JUST KEPT 3-6SM BR DURING THE 06-13Z THURSDAY PERIOD. VFR
CONDITIONS THRU 18Z THURSDAY WITH SOUTHWEST/WEST WINDS UNDER
10KTS.
OUTLOOK 18Z THURSDAY THROUGH SUNDAY...
18Z THURSDAY THROUGH SATURDAY...MAINLY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. SCATTERED AFTERNOOON SHOWERS/THUNDERSTORMS EACH DAY
THROUGH THE PERIOD WHICH MAY BRING BRIEF PERIODS OF MVFR/IFR
VISIBILITIES.
SUNDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.MARINE...
AS OF 310 PM EDT WEDNESDAY...STRONG THUNDERSTORMS WILL LIKELY
AFFECT THE LAKE CHAMPLAIN WATERS LATER THIS AFTERNOON AND EVENING.
A LAKE THUNDERSTORM ADVISORY IS IN EFFECT UNTIL FURTHER NOTICE.
WATCHING TWO LINES OF STRONG THUNDERSTORMS NOW OVER NORTHERN AND
EASTERN ONTARIO WHICH WILL SLIDE SOUTHEASTWARD ACROSS LAKE
CHAMPLAIN TONIGHT...WITH ADDITIONAL DEVELOPMENT POSSIBLE AHEAD OF
THE LINES OF ONGOING STORMS. STORMS WILL BE CAPABLE OF GUSTY TO
LOCALLY DAMAGING WINDS...ROUGH WAVES...AND CLOUD TO GROUND
LIGHTNING.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.EQUIPMENT...
WE CONTINUE TO EXPERIENCE LOSS OF SIGNAL/POWER WITH THE KTYX
RADAR...ALONG WITH IT GOING IN AND OUT OF SERVICE. TECHS HAVE BEEN
AT THE SITE LOOKING INTO THE PROBLEM AND HAVE OPENED A TICKET WITH
THE RADAR OPERATION CENTER. BOTTOM LINE EXPECT VERY LIMITED DATA
FROM THE KTYX RADAR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...TABER
SHORT TERM...TABER
LONG TERM...LOCONTO
AVIATION...LOCONTO
MARINE...
CLIMATE...
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
253 PM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
AS OF 250 PM EDT WEDNESDAY...UPDATE TO ZONES FOR SVR WATCH BOX
#416. EXPECTING SEVERAL ROUNDS OF STORMS...FIRST ACRS THE
SLV/OTTAWA VALLEY AND NORTHERN NY BTWN 3PM AND 5PM...THEN
SECONDARY AND MORE POTENT LINE OF STORMS APPROACHES NORTHERN ZNS
BTWN 22-00Z THIS EVENING. THIS WL HAVE POTENTIAL FOR A WELL
ORGANIZED LINE OF STORMS WITH ENHANCED BOWING SEGMENTS POSSIBLE.
STILL THINKING THE PRIMARY THREAT WL BE STRONG/DAMAGING
WINDS...WITH ISOLATED/SCATTERED POWER OUTAGES/TREES DOWN. THINKING
LINE WL ENTER CPV BTWN 01-02Z...AND DISSIPATE BY 03Z ACRS OUR
EASTERN CWA. THE MAIN CONCENTRATION WL BE ACRS NORTHERN NY INTO
CENTRAL/NORTHERN VT.
FCST IN GOOD SHAPE WITH A FEW MINOR ADJUSTMENTS. HAVE INCREASED
TEMPS AT PBG DUE TO DOWNSLOPE SW FLW OFF THE DACKS...ADJUSTED
SEVERAL DWPTS...AND SKY COVER GRIDS. BOTTOM LINE EXPECT HEAT INDEX
VALUES TO APPROACH 100 DEGREES IN THE WARMER VALLEY LOCATIONS AND
THUNDERSTORM ACTIVITY TO INCREASE IN AREAL COVERAGE/INTENSITY THIS
AFTN/EVENING.
CRNT RADAR SHOWS STORMS DEVELOPING NORTH OF LAKE ONTARIO AND
ANOTHER BATCH APPROACHING THE OTTAWA VALLEY. THESE STORMS WL
APPROACH THE SLV BY MID/LATE AFTN AND EVOLVE INTO A LINE OF SVR
STORMS...WITH DAMAGING WINDS AS THE PRIMARY SVR WX THREAT. GIVEN
WIND PROFILES AND INSTABILITY WOULD EXPECT SVR STORMS WITH THE
POTENTIAL FOR SCATTERED POWER OUTAGES/TREES DOWN ACRS NORTHERN NY
INTO PARTS OF CENTRAL/NORTHERN VT AS THIS LINE OF STORMS MOVES
ACRS THE REGION THIS EVENING.
ACTIVE WEATHER DAY ANTICIPATED ACRS THE NORTH COUNTRY...WITH THE
NEAR TERM CHALLENGE BEING TIMING/EVOLUTION OF CONVECTION THIS
AFTN/EVENING. WATER VAPOR SHOWS TWO PIECES OF ENERGY...FIRST IS
LOCATED JUST NORTH OF LAKE ONTARIO AND ANOTHER MUCH STRONGER ONE
IS LOCATED JUST NORTHEAST OF LAKE SUPERIOR. THINKING FIRST S/W WL
HELP IN THE DEVELOPMENT OF SHOWERS/STORMS ACRS THE DACKS/SLV BTWN
1PM AND 4PM THIS AFTN...WITH SOME STRONG STORMS POSSIBLE...GIVEN
CAPE VALUES BTWN 2000 AND 2500 J/KG AND DEEP LAYER SHEAR VALUES
BTWN 25 AND 30 KNTS. MEANWHILE...BETTER DYNAMICS/MOISTURE
ASSOCIATED WITH 2ND S/W WL ARRIVE ACRS THE OTTAWA AND SLV VALLEY`S
BTWN 21Z-00Z...WITH A LINE OF STRONG TO SEVERE STORMS LIKELY.
GIVEN THE AVAILABLE SHEAR AND INSTABILITY...THINKING LINE SEGMENTS
WITH ENHANCED BOW ECHOES WL BE POSSIBLE...WITH PRIMARY THREAT
BEING STRONG/DAMAGING WINDS GUSTS. CRNT SPC HAS OUR REGION IN
SLGHT RISK...WHICH LOOKS GOOD. ACTIVITY SHOULD WEAKEN TWD 03Z ACRS
CENTRAL/EASTERN VT. CWMW SOUNDINGS SHOW PW VALUES OF 1.66"...500MB
WINDS OF 50 KNOTS...AND VERY HIGH EL AROUND 43KFT...SO EXPECT
OVERSHOOTING STORM TOPS NEAR 50KFT THIS AFTN/EVENING WITH GREATEST
POTENTIAL BEING WINDS. 0 TO 6 KM STORM MOTIONS OF 20 TO 25 KNOTS
SHOULD LIMIT FLASH FLOOD THREAT...BUT WESTERN/SOUTHERN FLANK ACRS
THE DACKS WL HAVE TO BE WATCHED FOR POTENTIAL TRAINING...GIVEN
VECTOR ANALYSIS.
OTHERWISE...HIGHS IN THE L/M 90S WITH DWPTS BTWN 65 AND 70 WL
RESULT IN HEAT INDEX VALUES IN THE MID TO UPPER 90S. ALL IS
COVERED VERY WELL IN CRNT FCST AND ONLY MINOR CHANGES MADE BASED
ON CRNT OBS.
PRIOR DISCUSSION FOLLOWS...
FORECAST MORE OR LESS REMAINS ON TRACK FOR TODAY AS LARGE-SCALE
H5 HEAT RIDGE MAINTAINS ITS HOLD ON REGIONAL WEATHER. MEAN 18Z
925MB OF 23-25C SUPPORT HIGHS IN THE UPPER 80S TO MID 90S ACROSS
THE REGION ALONG WITH HIGH HUMIDITY...NOT A PLEASANT DAY. HEAT
INDEX VALUES TO PEAK JUST BELOW ADVISORY CRITERIA...GENERALLY IN
THE 92-98 RANGE IN LOWER ELEVATIONS BELOW 1000 FEET. THIS WILL BE
DAY 3 OF 90F+ AT KBTV SO OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA
WILL BE MET. OF COURSE NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS
OF 90F+...ESP IN SOME OF OUR NRN MTN LOCALES...BUT EVERYONE GETS
THE POINT THAT WE`RE IN A VERY WARM AND UNCOMFORTABLE STRETCH OF
WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY...ACTIVE AVIATION FORECAST FOR THIS AFTERNOON
AND EVENING WITH POTENTIAL FOR LOCALLY STG THUNDERSTORMS.
THUNDERSTORMS ARE CURRENTLY DEVELOPING IN THE OTTAWA AND THE
WESTERN SAINT LAWRENCE VALLEYS MOVING EAST-SOUTHEASTWARD. VFR
CONDITIONS EXPECTED TO PREVAIL UNTIL THUNDERSTORMS APPROACH WITH
GENERAL TIMING BETWEEN 18-05Z. ACTIVITY TO BEGIN WITHIN THE NEXT
HOUR OR TWO AT MSS AND SLK...INTO PBG AND BTV AROUND 23-00Z AND
AFTER 01Z FOR RUT AND MPV. POTENTIAL FOR STRONG TO LOCALLY
DAMAGING WINDS AND ASSOCIATED LLVL TURBULENCE...BRIEF PERIOD OF
MVFR TO IFR VISIBILITIES...AND LIGHTNING WITH THUNDERSTORMS.
WINDS WILL BE SOUTH AROUND 5-9KTS. WILL TREAT WITH VCSH FOR NOW
AND USE TEMPOS ACCORDINGLY. THUNDERSTORM ACTIVITY LOOKS TO END
AFTER 05Z WITH FOG/MIST POTENTIAL TONIGHT GIVEN SATURATED LOW-
LEVELS AND LIGHT SFC WINDS TONIGHT. AREAS THAT RECEIVE RAIN TODAY
WILL STAND A GREATER CHANCE AT FOG/MIST TONIGHT...SO FOR NOW HAVE
JUST KEPT 3-6SM BR DURING THE 06-13Z THURSDAY PERIOD. VFR
CONDITIONS THRU 18Z THURSDAY WITH SOUTHWEST/WEST WINDS UNDER
10KTS.
OUTLOOK 18Z THURSDAY THROUGH SUNDAY...
18Z THURSDAY THROUGH SATURDAY...MAINLY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. SCATTERED AFTERNOOON SHOWERS/THUNDERSTORMS EACH DAY
THROUGH THE PERIOD WHICH MAY BRING BRIEF PERIODS OF MVFR/IFR
VISIBILITIES.
SUNDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...LOCONTO
MARINE...
CLIMATE...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
141 PM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
AS OF 113 PM EDT WEDNESDAY...FCST IN GOOD SHAPE WITH A FEW MINOR
ADJUSTMENTS. HAVE INCREASED TEMPS AT PBG DUE TO DOWNSLOPE SW FLW
OFF THE DACKS...ADJUSTED SEVERAL DWPTS...AND SKY COVER GRIDS.
BOTTOM LINE EXPECT HEAT INDEX VALUES TO APPROACH 100 DEGREES IN
THE WARMER VALLEY LOCATIONS AND THUNDERSTORM ACTIVITY TO INCREASE
IN AREAL COVERAGE/INTENSITY THIS AFTN/EVENING.
CRNT RADAR SHOWS STORMS DEVELOPING NORTH OF LAKE ONTARIO AND
ANOTHER BATCH APPROACHING THE OTTAWA VALLEY. THESE STORMS WL
APPROACH THE SLV BY MID/LATE AFTN AND EVOLVE INTO A LINE OF SVR
STORMS...WITH DAMAGING WINDS AS THE PRIMARY SVR WX THREAT. GIVEN
WIND PROFILES AND INSTABILITY WOULD EXPECT SVR STORMS WITH THE
POTENTIAL FOR SCATTERED POWER OUTAGES/TREES DOWN ACRS NORTHERN NY
INTO PARTS OF CENTRAL/NORTHERN VT AS THIS LINE OF STORMS MOVES
ACRS THE REGION THIS EVENING.
ACTIVE WEATHER DAY ANTICIPATED ACRS THE NORTH COUNTRY...WITH THE
NEAR TERM CHALLENGE BEING TIMING/EVOLUTION OF CONVECTION THIS
AFTN/EVENING. WATER VAPOR SHOWS TWO PIECES OF ENERGY...FIRST IS
LOCATED JUST NORTH OF LAKE ONTARIO AND ANOTHER MUCH STRONGER ONE
IS LOCATED JUST NORTHEAST OF LAKE SUPERIOR. THINKING FIRST S/W WL
HELP IN THE DEVELOPMENT OF SHOWERS/STORMS ACRS THE DACKS/SLV BTWN
1PM AND 4PM THIS AFTN...WITH SOME STRONG STORMS POSSIBLE...GIVEN
CAPE VALUES BTWN 2000 AND 2500 J/KG AND DEEP LAYER SHEAR VALUES
BTWN 25 AND 30 KNTS. MEANWHILE...BETTER DYNAMICS/MOISTURE
ASSOCIATED WITH 2ND S/W WL ARRIVE ACRS THE OTTAWA AND SLV VALLEY`S
BTWN 21Z-00Z...WITH A LINE OF STRONG TO SEVERE STORMS LIKELY.
GIVEN THE AVAILABLE SHEAR AND INSTABILITY...THINKING LINE SEGMENTS
WITH ENHANCED BOW ECHOES WL BE POSSIBLE...WITH PRIMARY THREAT
BEING STRONG/DAMAGING WINDS GUSTS. CRNT SPC HAS OUR REGION IN
SLGHT RISK...WHICH LOOKS GOOD. ACTIVITY SHOULD WEAKEN TWD 03Z ACRS
CENTRAL/EASTERN VT. CWMW SOUNDINGS SHOW PW VALUES OF 1.66"...500MB
WINDS OF 50 KNOTS...AND VERY HIGH EL AROUND 43KFT...SO EXPECT
OVERSHOOTING STORM TOPS NEAR 50KFT THIS AFTN/EVENING WITH GREATEST
POTENTIAL BEING WINDS. 0 TO 6 KM STORM MOTIONS OF 20 TO 25 KNOTS
SHOULD LIMIT FLASH FLOOD THREAT...BUT WESTERN/SOUTHERN FLANK ACRS
THE DACKS WL HAVE TO BE WATCHED FOR POTENTIAL TRAINING...GIVEN
VECTOR ANALYSIS.
OTHERWISE...HIGHS IN THE L/M 90S WITH DWPTS BTWN 65 AND 70 WL
RESULT IN HEAT INDEX VALUES IN THE MID TO UPPER 90S. ALL IS
COVERED VERY WELL IN CRNT FCST AND ONLY MINOR CHANGES MADE BASED
ON CRNT OBS.
PRIOR DISCUSSION FOLLOWS...
FORECAST MORE OR LESS REMAINS ON TRACK FOR TODAY AS LARGE-SCALE
H5 HEAT RIDGE MAINTAINS ITS HOLD ON REGIONAL WEATHER. MEAN 18Z
925MB OF 23-25C SUPPORT HIGHS IN THE UPPER 80S TO MID 90S ACROSS
THE REGION ALONG WITH HIGH HUMIDITY...NOT A PLEASANT DAY. HEAT
INDEX VALUES TO PEAK JUST BELOW ADVISORY CRITERIA...GENERALLY IN
THE 92-98 RANGE IN LOWER ELEVATIONS BELOW 1000 FEET. THIS WILL BE
DAY 3 OF 90F+ AT KBTV SO OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA
WILL BE MET. OF COURSE NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS
OF 90F+...ESP IN SOME OF OUR NRN MTN LOCALES...BUT EVERYONE GETS
THE POINT THAT WE`RE IN A VERY WARM AND UNCOMFORTABLE STRETCH OF
WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY...ACTIVE AVIATION FORECAST FOR THIS AFTERNOON
AND EVENING WITH POTENTIAL FOR LOCALLY STG THUNDERSTORMS.
THUNDERSTORMS ARE CURRENTLY DEVELOPING IN THE OTTAWA AND THE
WESTERN SAINT LAWRENCE VALLEYS MOVING EAST-SOUTHEASTWARD. VFR
CONDITIONS EXPECTED TO PREVAIL UNTIL THUNDERSTORMS APPROACH WITH
GENERAL TIMING BETWEEN 18-05Z. ACTIVITY TO BEGIN WITHIN THE NEXT
HOUR OR TWO AT MSS AND SLK...INTO PBG AND BTV AROUND 23-00Z AND
AFTER 01Z FOR RUT AND MPV. POTENTIAL FOR STRONG TO LOCALLY
DAMAGING WINDS AND ASSOCIATED LLVL TURBULENCE...BRIEF PERIOD OF
MVFR TO IFR VISIBILITIES...AND LIGHTNING WITH THUNDERSTORMS.
WINDS WILL BE SOUTH AROUND 5-9KTS. WILL TREAT WITH VCSH FOR NOW
AND USE TEMPOS ACCORDINGLY. THUNDERSTORM ACTIVITY LOOKS TO END
AFTER 05Z WITH FOG/MIST POTENTIAL TONIGHT GIVEN SATURATED LOW-
LEVELS AND LIGHT SFC WINDS TONIGHT. AREAS THAT RECEIVE RAIN TODAY
WILL STAND A GREATER CHANCE AT FOG/MIST TONIGHT...SO FOR NOW HAVE
JUST KEPT 3-6SM BR DURING THE 06-13Z THURSDAY PERIOD. VFR
CONDITIONS THRU 18Z THURSDAY WITH SOUTHWEST/WEST WINDS UNDER
10KTS.
OUTLOOK 18Z THURSDAY THROUGH SUNDAY...
18Z THURSDAY THROUGH SATURDAY...MAINLY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. SCATTERED AFTERNOOON SHOWERS/THUNDERSTORMS EACH DAY
THROUGH THE PERIOD WHICH MAY BRING BRIEF PERIODS OF MVFR/IFR
VISIBILITIES.
SUNDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...LOCONTO
MARINE...
CLIMATE...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
123 PM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
AS OF 113 PM EDT WEDNESDAY...FCST IN GOOD SHAPE WITH A FEW MINOR
ADJUSTMENTS. HAVE INCREASED TEMPS AT PBG DUE TO DOWNSLOPE SW FLW
OFF THE DACKS...ADJUSTED SEVERAL DWPTS...AND SKY COVER GRIDS.
BOTTOM LINE EXPECT HEAT INDEX VALUES TO APPROACH 100 DEGREES IN
THE WARMER VALLEY LOCATIONS AND THUNDERSTORM ACTIVITY TO INCREASE
IN AREAL COVERAGE/INTENSITY THIS AFTN/EVENING.
CRNT RADAR SHOWS STORMS DEVELOPING NORTH OF LAKE ONTARIO AND
ANOTHER BATCH APPROACHING THE OTTAWA VALLEY. THESE STORMS WL
APPROACH THE SLV BY MID/LATE AFTN AND EVOLVE INTO A LINE OF SVR
STORMS...WITH DAMAGING WINDS AS THE PRIMARY SVR WX THREAT. GIVEN
WIND PROFILES AND INSTABILITY WOULD EXPECT SVR STORMS WITH THE
POTENTIAL FOR SCATTERED POWER OUTAGES/TREES DOWN ACRS NORTHERN NY
INTO PARTS OF CENTRAL/NORTHERN VT AS THIS LINE OF STORMS MOVES
ACRS THE REGION THIS EVENING.
ACTIVE WEATHER DAY ANTICIPATED ACRS THE NORTH COUNTRY...WITH THE
NEAR TERM CHALLENGE BEING TIMING/EVOLUTION OF CONVECTION THIS
AFTN/EVENING. WATER VAPOR SHOWS TWO PIECES OF ENERGY...FIRST IS
LOCATED JUST NORTH OF LAKE ONTARIO AND ANOTHER MUCH STRONGER ONE
IS LOCATED JUST NORTHEAST OF LAKE SUPERIOR. THINKING FIRST S/W WL
HELP IN THE DEVELOPMENT OF SHOWERS/STORMS ACRS THE DACKS/SLV BTWN
1PM AND 4PM THIS AFTN...WITH SOME STRONG STORMS POSSIBLE...GIVEN
CAPE VALUES BTWN 2000 AND 2500 J/KG AND DEEP LAYER SHEAR VALUES
BTWN 25 AND 30 KNTS. MEANWHILE...BETTER DYNAMICS/MOISTURE
ASSOCIATED WITH 2ND S/W WL ARRIVE ACRS THE OTTAWA AND SLV VALLEY`S
BTWN 21Z-00Z...WITH A LINE OF STRONG TO SEVERE STORMS LIKELY.
GIVEN THE AVAILABLE SHEAR AND INSTABILITY...THINKING LINE SEGMENTS
WITH ENHANCED BOW ECHOES WL BE POSSIBLE...WITH PRIMARY THREAT
BEING STRONG/DAMAGING WINDS GUSTS. CRNT SPC HAS OUR REGION IN
SLGHT RISK...WHICH LOOKS GOOD. ACTIVITY SHOULD WEAKEN TWD 03Z ACRS
CENTRAL/EASTERN VT. CWMW SOUNDINGS SHOW PW VALUES OF 1.66"...500MB
WINDS OF 50 KNOTS...AND VERY HIGH EL AROUND 43KFT...SO EXPECT
OVERSHOOTING STORM TOPS NEAR 50KFT THIS AFTN/EVENING WITH GREATEST
POTENTIAL BEING WINDS. 0 TO 6 KM STORM MOTIONS OF 20 TO 25 KNOTS
SHOULD LIMIT FLASH FLOOD THREAT...BUT WESTERN/SOUTHERN FLANK ACRS
THE DACKS WL HAVE TO BE WATCHED FOR POTENTIAL TRAINING...GIVEN
VECTOR ANALYSIS.
OTHERWISE...HIGHS IN THE L/M 90S WITH DWPTS BTWN 65 AND 70 WL
RESULT IN HEAT INDEX VALUES IN THE MID TO UPPER 90S. ALL IS
COVERED VERY WELL IN CRNT FCST AND ONLY MINOR CHANGES MADE BASED
ON CRNT OBS.
PRIOR DISCUSSION FOLLOWS...
FORECAST MORE OR LESS REMAINS ON TRACK FOR TODAY AS LARGE-SCALE
H5 HEAT RIDGE MAINTAINS ITS HOLD ON REGIONAL WEATHER. MEAN 18Z
925MB OF 23-25C SUPPORT HIGHS IN THE UPPER 80S TO MID 90S ACROSS
THE REGION ALONG WITH HIGH HUMIDITY...NOT A PLEASANT DAY. HEAT
INDEX VALUES TO PEAK JUST BELOW ADVISORY CRITERIA...GENERALLY IN
THE 92-98 RANGE IN LOWER ELEVATIONS BELOW 1000 FEET. THIS WILL BE
DAY 3 OF 90F+ AT KBTV SO OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA
WILL BE MET. OF COURSE NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS
OF 90F+...ESP IN SOME OF OUR NRN MTN LOCALES...BUT EVERYONE GETS
THE POINT THAT WE`RE IN A VERY WARM AND UNCOMFORTABLE STRETCH OF
WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /17Z WEDNESDAY THROUGH MONDAY/...
THROUGH 12Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH AT
LEAST THE EARLY EVENING HOURS...AS KMPV RECOVERS FROM VLIFR THIS
MORNING. SFC TROUGH GENERATING SCT-BKN MID LEVEL CLOUDS THIS
MORNING BEFORE DIURNALLY DRIVEN VFR CLOUDS DEVELOP IN THE HOT
HUMID DAYTIME...WITH INSTABILITY INCREASING THROUGHOUT THE LATE
AFTN/EVENING HRS. LGT TO CALM WINDS THIS MORNING WILL INCREASE TO
8-12KTS OUT OF THE S-SW IN THE MID-LATE MORNING...SHIFTING SW-W
THIS AFTN WITH GUSTS PSBL.
A BOUNDARY ASSOCIATED UPPER LEVEL VORTICITY WILL TRIGGER SCT
SHOWERS AND THUNDERSTORMS NORTH OF THE INTERNATIONAL BORDER IN
THE LATE AFTN...TRAVELING S/SE AND MOST LIKELY AFFECTING
KMSS/KPBG/KBTV AND PSBLY KSLK/KMPV. EXPECT SCT SHOWERS AND
THUNDERSTORMS TO TRAVEL FROM NW TO SSE...AFFECTING KMSS AROUND
20Z...KPBG/KBTV/KMPV AROUND 23Z/00Z. HAVE INCLUDED VCSH AT ALL
BUT KRUT AS WESTERLY WINDS WILL HELP SHOWERS AND THUNDERSTORMS
LOSE MOMENTUM SWD...WHILE LOSS OF DIURNAL HEATING AFTER SUNSET
WEAKENS CONVECTIVE ACTIVITY. EXPECT SHOWERS AND THUNDERSTORMS TO
DISSIPATE AFTER 04Z. THUNDERSTORMS MAY CONTAIN STRONG GUSTY
WINDS. ANY AREA THAT RECEIVES RAINFALL COULD DEVELOP FG/BR MAINLY
AFTER 04Z THURSDAY. EXPECT PATCHY FG TO DEVELOP AT MOST TAF SITES
OVERNIGHT...RECOVERING TO VFR MID TO LATE THURSDAY MORNING.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
12Z THURSDAY THROUGH SATURDAY...PRIMARILY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. HOWEVER...CHANCES INCREASE FOR SCATTERED
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD WHICH MAY BRING BRIEF
PERIODS OF MVFR/IFR IN SHOWERS AND THUNDERSTORMS.
SUNDAY...VFR WITH HIGH PRESSURE BUILDING IN AT THE SFC.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
MARINE...
CLIMATE...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1023 AM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
AS OF 1020 AM EDT WEDNESDAY...ACTIVE WEATHER DAY ANTICIPATED ACRS
THE NORTH COUNTRY...WITH THE NEAR TERM CHALLENGE BEING
TIMING/EVOLUTION OF CONVECTION THIS AFTN/EVENING. WATER VAPOR
SHOWS TWO PIECES OF ENERGY...FIRST IS LOCATED JUST NORTH OF LAKE
ONTARIO AND ANOTHER MUCH STRONGER ONE IS LOCATED JUST NORTHEAST OF
LAKE SUPERIOR. THINKING FIRST S/W WL HELP IN THE DEVELOPMENT OF
SHOWERS/STORMS ACRS THE DACKS/SLV BTWN 1PM AND 4PM THIS
AFTN...WITH SOME STRONG STORMS POSSIBLE...GIVEN CAPE VALUES BTWN
2000 AND 2500 J/KG AND DEEP LAYER SHEAR VALUES BTWN 25 AND 30
KNTS. MEANWHILE...BETTER DYNAMICS/MOISTURE ASSOCIATED WITH 2ND S/W
WL ARRIVE ACRS THE OTTAWA AND SLV VALLEY`S BTWN 21Z-00Z...WITH A
LINE OF STRONG TO SEVERE STORMS LIKELY. GIVEN THE AVAILABLE SHEAR
AND INSTABILITY...THINKING LINE SEGMENTS WITH ENHANCED BOW ECHOES
WL BE POSSIBLE...WITH PRIMARY THREAT BEING STRONG/DAMAGING WINDS
GUSTS. CRNT SPC HAS OUR REGION IN SLGHT RISK...WHICH LOOKS GOOD.
ACTIVITY SHOULD WEAKEN TWD 03Z ACRS CENTRAL/EASTERN VT. CWMW
SOUNDINGS SHOW PW VALUES OF 1.66"...500MB WINDS OF 50 KNOTS...AND
VERY HIGH EL AROUND 43KFT...SO EXPECT OVERSHOOTING STORM TOPS NEAR
50KFT THIS AFTN/EVENING WITH GREATEST POTENTIAL BEING WINDS. 0 TO
6 KM STORM MOTIONS OF 20 TO 25 KNOTS SHOULD LIMIT FLASH FLOOD
THREAT...BUT WESTERN/SOUTHERN FLANK ACRS THE DACKS WL HAVE TO BE
WATCHED FOR POTENTIAL TRAINING...GIVEN VECTOR ANALYSIS.
OTHERWISE...HIGHS IN THE L/M 90S WITH DWPTS BTWN 65 AND 70 WL
RESULT IN HEAT INDEX VALUES IN THE MID TO UPPER 90S. ALL IS
COVERED VERY WELL IN CRNT FCST AND ONLY MINOR CHANGES MADE BASED
ON CRNT OBS.
PRIOR DISCUSSION FOLLOWS...
FORECAST MORE OR LESS REMAINS ON TRACK FOR TODAY AS LARGE-SCALE
H5 HEAT RIDGE MAINTAINS ITS HOLD ON REGIONAL WEATHER. MEAN 18Z
925MB OF 23-25C SUPPORT HIGHS IN THE UPPER 80S TO MID 90S ACROSS
THE REGION ALONG WITH HIGH HUMIDITY...NOT A PLEASANT DAY. HEAT
INDEX VALUES TO PEAK JUST BELOW ADVISORY CRITERIA...GENERALLY IN
THE 92-98 RANGE IN LOWER ELEVATIONS BELOW 1000 FEET. THIS WILL BE
DAY 3 OF 90F+ AT KBTV SO OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA
WILL BE MET. OF COURSE NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS
OF 90F+...ESP IN SOME OF OUR NRN MTN LOCALES...BUT EVERYONE GETS
THE POINT THAT WE`RE IN A VERY WARM AND UNCOMFORTABLE STRETCH OF
WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH AT
LEAST THE EARLY EVENING HOURS...AS KMPV RECOVERS FROM VLIFR THIS
MORNING. SFC TROUGH GENERATING SCT-BKN MID LEVEL CLOUDS THIS
MORNING BEFORE DIURNALLY DRIVEN VFR CLOUDS DEVELOP IN THE HOT
HUMID DAYTIME...WITH INSTABILITY INCREASING THROUGHOUT THE LATE
AFTN/EVENING HRS. LGT TO CALM WINDS THIS MORNING WILL INCREASE TO
8-12KTS OUT OF THE S-SW IN THE MID-LATE MORNING...SHIFTING SW-W
THIS AFTN WITH GUSTS PSBL.
A BOUNDARY ASSOCIATED UPPER LEVEL VORTICITY WILL TRIGGER SCT
SHOWERS AND THUNDERSTORMS NORTH OF THE INTERNATIONAL BORDER IN
THE LATE AFTN...TRAVELING S/SE AND MOST LIKELY AFFECTING
KMSS/KPBG/KBTV AND PSBLY KSLK/KMPV. EXPECT SCT SHOWERS AND
THUNDERSTORMS TO TRAVEL FROM NW TO SSE...AFFECTING KMSS AROUND
20Z...KPBG/KBTV/KMPV AROUND 23Z/00Z. HAVE INCLUDED VCSH AT ALL
BUT KRUT AS WESTERLY WINDS WILL HELP SHOWERS AND THUNDERSTORMS
LOSE MOMENTUM SWD...WHILE LOSS OF DIURNAL HEATING AFTER SUNSET
WEAKENS CONVECTIVE ACTIVITY. EXPECT SHOWERS AND THUNDERSTORMS TO
DISSIPATE AFTER 04Z. THUNDERSTORMS MAY CONTAIN STRONG GUSTY
WINDS. ANY AREA THAT RECEIVES RAINFALL COULD DEVELOP FG/BR MAINLY
AFTER 04Z THURSDAY. EXPECT PATCHY FG TO DEVELOP AT MOST TAF SITES
OVERNIGHT...RECOVERING TO VFR MID TO LATE THURSDAY MORNING.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
12Z THURSDAY THROUGH SATURDAY...PRIMARILY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. HOWEVER...CHANCES INCREASE FOR SCATTERED
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD WHICH MAY BRING BRIEF
PERIODS OF MVFR/IFR IN SHOWERS AND THUNDERSTORMS.
SUNDAY...VFR WITH HIGH PRESSURE BUILDING IN AT THE SFC.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/TABER
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
MARINE...
CLIMATE...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
738 AM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 550 AM EDT WEDNESDAY...QUICK UPDATE TO ACCOUNT FOR ISOLATED
SHOWERS FAR NERN VT OVER THE NEXT FEW HOURS...AND TO INCORPORATE
LATEST T/TD/SKY DATA INTO EXISTENT DATASETS. OTW FORECAST IN GOOD
SHAPE. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS...
FORECAST MORE OR LESS REMAINS ON TRACK FOR TODAY AS LARGE-SCALE H5
HEAT RIDGE MAINTAINS ITS HOLD ON REGIONAL WEATHER. MEAN 18Z 925MB
OF 23-25C SUPPORT HIGHS IN THE UPPER 80S TO MID 90S ACROSS THE
REGION ALONG WITH HIGH HUMIDITY...NOT A PLEASANT DAY. HEAT INDEX
VALUES TO PEAK JUST BELOW ADVISORY CRITERIA...GENERALLY IN THE
92-98 RANGE IN LOWER ELEVATIONS BELOW 1000 FEET. THIS WILL BE DAY
3 OF 90F+ AT KBTV SO OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA WILL
BE MET. OF COURSE NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS OF
90F+...ESP IN SOME OF OUR NRN MTN LOCALES...BUT EVERYONE GETS THE
POINT THAT WE`RE IN A VERY WARM AND UNCOMFORTABLE STRETCH OF WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH AT
LEAST THE EARLY EVENING HOURS...AS KMPV RECOVERS FROM VLIFR THIS
MORNING. SFC TROUGH GENERATING SCT-BKN MID LEVEL CLOUDS THIS
MORNING BEFORE DIURNALLY DRIVEN VFR CLOUDS DEVELOP IN THE HOT
HUMID DAYTIME...WITH INSTABILITY INCREASING THROUGHOUT THE LATE
AFTN/EVENING HRS. LGT TO CALM WINDS THIS MORNING WILL INCREASE TO
8-12KTS OUT OF THE S-SW IN THE MID-LATE MORNING...SHIFTING SW-W
THIS AFTN WITH GUSTS PSBL.
A BOUNDARY ASSOCIATED UPPER LEVEL VORTICITY WILL TRIGGER SCT
SHOWERS AND THUNDERSTORMS NORTH OF THE INTERNATIONAL BORDER IN
THE LATE AFTN...TRAVELING S/SE AND MOST LIKELY AFFECTING
KMSS/KPBG/KBTV AND PSBLY KSLK/KMPV. EXPECT SCT SHOWERS AND
THUNDERSTORMS TO TRAVEL FROM NW TO SSE...AFFECTING KMSS AROUND
20Z...KPBG/KBTV/KMPV AROUND 23Z/00Z. HAVE INCLUDED VCSH AT ALL
BUT KRUT AS WESTERLY WINDS WILL HELP SHOWERS AND THUNDERSTORMS
LOSE MOMENTUM SWD...WHILE LOSS OF DIURNAL HEATING AFTER SUNSET
WEAKENS CONVECTIVE ACTIVITY. EXPECT SHOWERS AND THUNDERSTORMS TO
DISSIPATE AFTER 04Z. THUNDERSTORMS MAY CONTAIN STRONG GUSTY
WINDS. ANY AREA THAT RECEIVES RAINFALL COULD DEVELOP FG/BR MAINLY
AFTER 04Z THURSDAY. EXPECT PATCHY FG TO DEVELOP AT MOST TAF SITES
OVERNIGHT...RECOVERING TO VFR MID TO LATE THURSDAY MORNING.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
12Z THURSDAY THROUGH SATURDAY...PRIMARILY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. HOWEVER...CHANCES INCREASE FOR SCATTERED
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD WHICH MAY BRING BRIEF
PERIODS OF MVFR/IFR IN SHOWERS AND THUNDERSTORMS.
SUNDAY...VFR WITH HIGH PRESSURE BUILDING IN AT THE SFC.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
MARINE...JMG
CLIMATE...JMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
550 AM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 550 AM EDT WEDNESDAY...QUICK UPDATE TO ACCOUNT FOR ISOLATED
SHOWERS FAR NERN VT OVER THE NEXT FEW HOURS...AND TO INCORPORATE
LATEST T/TD/SKY DATA INTO EXISTENT DATASETS. OTW FORECAST IN GOOD
SHAPE. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS...
FORECAST MORE OR LESS REMAINS ON TRACK FOR TODAY AS LARGE-SCALE H5
HEAT RIDGE MAINTAINS ITS HOLD ON REGIONAL WEATHER. MEAN 18Z 925MB
OF 23-25C SUPPORT HIGHS IN THE UPPER 80S TO MID 90S ACROSS THE
REGION ALONG WITH HIGH HUMIDITY...NOT A PLEASANT DAY. HEAT INDEX
VALUES TO PEAK JUST BELOW ADVISORY CRITERIA...GENERALLY IN THE
92-98 RANGE IN LOWER ELEVATIONS BELOW 1000 FEET. THIS WILL BE DAY
3 OF 90F+ AT KBTV SO OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA WILL
BE MET. OF COURSE NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS OF
90F+...ESP IN SOME OF OUR NRN MTN LOCALES...BUT EVERYONE GETS THE
POINT THAT WE`RE IN A VERY WARM AND UNCOMFORTABLE STRETCH OF WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH AT
LEAST THE LATE AFTN/EARLY EVENING HOURS...WITH EXCEPTION OF KSLK
AND KMPV THIS MORNING EXPERIENCING SOME MVFR AND PSBL IFR AT KSLK
THROUGH 12Z. DIURNALLY DRIVEN VFR CLOUDS WILL DEVELOP IN THE HOT
HUMID DAYTIME...WITH INSTABILITY INCREASING THROUGHOUT THE LATE
AFTN/EVENING HRS. LGT TO CALM WINDS THIS MORNING WILL INCREASE TO
8-12KTS OUT OF THE S-SW IN THE MID-LATE MORNING...SHIFTING SW-W
THIS AFTN.
A PACKET OF VORTICITY WILL TRIGGER SHOWERS AND THUNDERSTORMS
NORTH OF THE INTERNATIONAL BORDER IN THE LATE AFTN...TRAVEL LING
SOUTH AND MOST LIKELY AFFECTING KMSS/KPBG/KBTV AND PSBLY
KSLK/KMPV. HAVE INCLUDED VCSH AT ALL BUT KRUT AS WESTERLY WINDS
WILL HELP SHOWERS AND THUNDERSTORMS LOSE MOMENTUM SWD...WHILE
LOSS OF DIURNAL HEATING AFTER SUNSET WEAKENS CONVECTIVE ACTIVITY.
EXPECT SHOWERS AND THUNDERSTORMS TO DISSIPATE AFTER 04Z.
THUNDERSTORMS MAY CONTAIN STRONG GUSTY WINDS. ANY AREA THAT
RECEIVES RAINFALL COULD DEVELOP FG/BR MAINLY AFTER 04Z THURSDAY.
OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
06Z THURSDAY THROUGH SATURDAY...PRIMARILY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. HOWEVER...CHANCES INCREASE FOR SCATTERED
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD WHICH MAY BRING BRIEF
PERIODS OF MVFR/IFR IN SHOWERS AND THUNDERSTORMS.
SUNDAY...VFR WITH HIGH PRESSURE BUILDING IN AT THE SFC.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
MARINE...JMG
CLIMATE...JMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
436 AM EDT WED JUL 17 2013
.SYNOPSIS...
HOT AND HUMID WEATHER IS EXPECTED THROUGH FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS COULD BE STRONG TO SEVERE LATER THIS AFTERNOON AND
EVENING. SHOWERS AND STORMS WILL END NORTH TO SOUTH DURING
SATURDAY AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. BEHIND
THIS FRONT...A MORE SEASONABLE AND PLEASANTLY DRIER AIRMASS WILL
SETTLE ACROSS THE REGION FROM SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 420 AM EDT WEDNESDAY...FORECAST MORE OR LESS REMAINS ON
TRACK FOR TODAY AS LARGE-SCALE H5 HEAT RIDGE MAINTAINS ITS HOLD
ON REGIONAL WEATHER. MEAN 18Z 925MB OF 23-25C SUPPORT HIGHS IN
THE UPPER 80S TO MID 90S ACROSS THE REGION ALONG WITH HIGH
HUMIDITY...NOT A PLEASANT DAY. HEAT INDEX VALUES TO PEAK JUST
BELOW ADVISORY CRITERIA...GENERALLY IN THE 92-98 RANGE IN LOWER
ELEVATIONS BELOW 1000 FEET. THIS WILL BE DAY 3 OF 90F+ AT KBTV SO
OFFICIAL NEW ENGLAND HEAT WAVE CRITERIA WILL BE MET. OF COURSE
NOT ALL AREAS HAVE SEEN 3 CONSECUTIVE DAYS OF 90F+...ESP IN SOME
OF OUR NRN MTN LOCALES...BUT EVERYONE GETS THE POINT THAT WE`RE
IN A VERY WARM AND UNCOMFORTABLE STRETCH OF WX.
COULD SEE SOME ISOLATED AFTERNOON PULSE-TYPE STORMS IN THE 1 TO 4
PM TIME FRAME OF SO...BUT INITIALLY MID LEVELS WILL BE SLIGHTLY
CAPPED SUCH THAT UPDRAFTS WILL BE INHIBITED. MORE IMPORTANTLY
HOWEVER WILL BE THE POTENTIAL FOR A LINE OF STRONG TO LOCALLY
SEVERE STORMS TO DROP SOUTHWARD INTO OUR NORTHERN COUNTIES LATER
THIS AFTERNOON OR EARLY EVENING AS A WEAK SURFACE FRONT
APPROACHES FROM THE NORTHWEST. WITH SLIGHT MID LEVEL HEIGHT FALLS
...AMPLE PBL INSTABILITY AND MODEST 0-6KM SHEAR VALUES INCREASING
INTO THE 30-40 KT RANGE ACROSS THE NORTH...THE THREAT FOR STRONG
TO LOCALLY SEVERE STORMS TO DEVELOP ALONG THIS LINE IS
INCREASING. VERY TALL STORMS WITH TOPS TO NEAR 50 KFT POSSIBLE
WITH EQ LEVELS VERY HIGH. MODIFIED KMSS AND KFSO SOUNDINGS
CENTERED AROUND 00Z SHOW QUITE ROBUST SWEAT AND DCAPE VALUES...SO
STRONG OUTFLOW/DAMAGING WINDS LOOK LIKE THE PRIMARY
THREAT...ESPECIALLY IF ACTIVITY CAN ORGANIZE ENOUGH TO GENERATE
AN AMPLE COLD POOL. HAIL NOT SO MUCH AN ISSUE GIVEN MEAN WBZ
VALUES ABOVE 12 KFT. STORMS WILL TEND TO WEAKEN AS THEY PROGRESS
SOUTHWARD THROUGH OUR REGION...SO HIGHEST THREAT WILL BE ACROSS
OUR NORTHERN COUNTIES WITH LESS OF A THREAT THE FURTHER SOUTH YOU
GO. WILL ALSO CONTINUE MENTION OF HEAVY RAINFALL AS PWATS CLIMB
TO NEAR 1.9 INCHES ALONG WITH LOW TO MID LEVEL MOISTURE POOLING
IN ADVANCE OF THE SURFACE BOUNDARY.
BY LATER THIS EVENING INTO TONIGHT ACTIVITY SLOWLY WANES AND
TAPERS TO SCATTERED SHOWERS ACROSS OUR CENTRAL AND NORTHERN
COUNTIES AS WEAK FRONTAL BOUNDARY SAGS INTO THE REGION AND
STALLS. PATCHY FOG ALSO A GOOD BET IF WE SEE HEAVIER WETTING
RAINFALL. LOWS MILD AND HUMID...MID 60S TO LOWER 70S...OR SIMILAR
TO THE PAST FEW NIGHTS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 420 AM EDT WEDNESDAY...BY THURSDAY STALLED WEAK SURFACE
BOUNDARY REMAINS DRAPED ACROSS OUR AREA ALONG WITH CONTINUED
WARMTH AND HUMIDITY. SCATTERED SHOWERS AND STORMS ALSO A GOOD BET
WITH LOCALLY HEAVY RAINFALL ONCE AGAIN. MBE VECTOR VALUES ARE
GENERALLY GREATER THAN 10 KTS HOWEVER...SO MY FEELING IS STORMS
MAY BE MOVING ENOUGH TO PRECLUDE A MORE ORGANIZED FLASH FLOOD
THREAT. NONETHELESS WE`LL HAVE TO KEEP AN EYE ON THINGS WITH PWAT
VALUES HOVERING AROUND 2.0 INCHES. DESPITE AMPLE SHEAR AND
INSTABILITY...FEEL ANY SEVERE THREAT SHOULD BE FAIRLY MARGINAL AS
WE REALLY DON`T HAVE A STRONG MECHANISM FOR LIFT OTHER THAN THE
SFC HEATING AND THE WEAK BOUNDARY. TIME WILL TELL. HIGHS ABOUT
2-4 DEGREES COOLER THAN TODAY SO SOME SLIGHT RELIEF BUT NOT MUCH.
SPOT HIGH FOR KBTV AT 89-90F LOOKS REASONABLE.
FRONT THEN REMAINS ATOP OUR REGION THURSDAY NIGHT INTO
FRIDAY...LIFTING SLOWLY NORTHWARD AND DISSIPATING THROUGH TIME IN
RESPONSE TO LARGE-SCALE BACKING OF THE MID LEVEL FLOW AHEAD OF A
MORE ROBUST NRN STREAM UPPER TROUGH OFF TO OUR NORTHWEST. THUS
CHANCE OF SHOWERS AND STORMS CONTINUE...BUT HIGHER CHANCES TREND
MORE ACROSS OUR NORTHERN COUNTIES. LIKELY A REPEAT OF TODAYS HOT
VALUES BY FRIDAY WITH MODELS HAVING CONSISTENTLY TRENDED WARMER
OVER THE PAST 24-HOURS. INDEED...WITH MEAN 925MB TEMPS AVERAGING
FROM 24-26C FRIDAY COULD END UP AS HOT IF NOT A DEGREE OR TWO
HOTTER THAN TODAY...ESPECIALLY IF WE SEE AMPLE SUNSHINE. SO IT`S
NOT ENTIRELY UNREASONABLE TO SUGGEST IF WE HIT 90F AT KBTV ON
THURSDAY...A FIVE DAY STRETCH OF 90F+ WILL BE IN REACH. THE LAST
TIME THIS OCCURRED WAS BACK IN AUGUST 2002.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 436 AM EDT WEDNESDAY...SFC LOW PRESSURE SYSTEM WILL START
THE PERIOD WITH SHOWERS/THUNDERSTORMS AND WARM TEMPERATURES...
FOLLOWED BY HIGH PRESSURE AND A COOLER...DRIER AIRMASS. FRIDAY
NIGHT WILL SEE THE NORTH COUNTRY STILL IN THE WARM SECTOR AND SW
FLOW AS A PREFRONTAL TROUGH AT THE SFC TRIGGERS
SHOWERS/THUNDERSTORMS FOLLOWED BY ASSOCIATED COLD FRONT ON
SATURDAY CONTINUING THE THREAT FOR SHOWERS AND THUNDERSTORMS.
FAVORABLE UPPER LEVEL JET DYNAMICS WILL ACCOMPANY THE COLD FRONT
WITH RR QUADRANT OF 250MB JET MOVES OVER THE NORTH COUNTRY MAINLY
ON SATURDAY...COINCIDING WITH STRONG FGEN AT 850MB...LINGERING
INTO SATURDAY NIGHT. PWATS OF 1.5-2 INCHES WILL PEAK EARLY
SATURDAY AS THE FRONT MOVES FROM SE ONTARIO...SEWD AND EVENTUALLY
EXIT VT EARLY SUNDAY AS ASSOCIATED UPPER LEVEL TROUGH PUSHES NEWD
SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN OVER THE REGION
FOLLOWING THE FRONT SUNDAY THROUGH AT LEAST MONDAY. MONDAY NIGHT
INTO TUESDAY...THE 00Z ECMWF BRINGS ANOTHER UPPER LEVEL TROUGH
OVER THE REGION...PRODUCING SHOWERS WHILE THE GFS KEEPS THE HIGH
PRESSURE ENTRENCHED OVER NRN NEW ENGLAND THROUGH THE MIDDLE OF
THE WEEK.
TEMPERATURES WILL BE WARM AND MUGGY...WITH MIN TEMPS FRIDAY NIGHT
IN THE 60S-L70S AND MAX TEMPS ON SATURDAY RANGING FORM M70S TO
M80S. COOLER AIR WILL FILTER IN FOR THE REST OF THE PERIOD WITH
MIN TEMPS TRENDING COOLER. SATURDAY NIGHT WILL BE IN THE 50S-
L60S...WITH SUNDAY NT THRU TUES NT IN THE M40S-U50S. MAX TEMPS
WILL GENERALLY BE IN THE 70S.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH AT
LEAST THE LATE AFTN/EARLY EVENING HOURS...WITH EXCEPTION OF KSLK
AND KMPV THIS MORNING EXPERIENCING SOME MVFR AND PSBL IFR AT KSLK
THROUGH 12Z. DIURNALLY DRIVEN VFR CLOUDS WILL DEVELOP IN THE HOT
HUMID DAYTIME...WITH INSTABILITY INCREASING THROUGHOUT THE LATE
AFTN/EVENING HRS. LGT TO CALM WINDS THIS MORNING WILL INCREASE TO
8-12KTS OUT OF THE S-SW IN THE MID-LATE MORNING...SHIFTING SW-W
THIS AFTN.
A PACKET OF VORTICITY WILL TRIGGER SHOWERS AND THUNDERSTORMS
NORTH OF THE INTERNATIONAL BORDER IN THE LATE AFTN...TRAVEL LING
SOUTH AND MOST LIKELY AFFECTING KMSS/KPBG/KBTV AND PSBLY
KSLK/KMPV. HAVE INCLUDED VCSH AT ALL BUT KRUT AS WESTERLY WINDS
WILL HELP SHOWERS AND THUNDERSTORMS LOSE MOMENTUM SWD...WHILE
LOSS OF DIURNAL HEATING AFTER SUNSET WEAKENS CONVECTIVE ACTIVITY.
EXPECT SHOWERS AND THUNDERSTORMS TO DISSIPATE AFTER 04Z.
THUNDERSTORMS MAY CONTAIN STRONG GUSTY WINDS. ANY AREA THAT
RECEIVES RAINFALL COULD DEVELOP FG/BR MAINLY AFTER 04Z THURSDAY.
OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
06Z THURSDAY THROUGH SATURDAY...PRIMARILY VFR CONDITIONS EXPECTED
DURING THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. HOWEVER...CHANCES INCREASE FOR SCATTERED
SHOWERS/THUNDERSTORMS THROUGH THE PERIOD WHICH MAY BRING BRIEF
PERIODS OF MVFR/IFR IN SHOWERS AND THUNDERSTORMS.
SUNDAY...VFR WITH HIGH PRESSURE BUILDING IN AT THE SFC.
&&
.MARINE...
AS OF 420 AM EDT WEDNESDAY...STRONG TO LOCALLY SEVERE
THUNDERSTORMS MAY EFFECT THE LAKE CHAMPLAIN WATERS LATER THIS
AFTERNOON AND EVENING. IF STORMS DO DEVELOP...THEY WILL LIKELY
APPROACH FROM THE NORTH AND NORTHWEST AFTER 3 PM AND MAY BE
ACCOMPANIED BY VERY STRONG GUSTY WINDS AND FREQUENT CLOUD TO
GROUND LIGHTNING. IF PLANNING ACTIVITIES ON THE LAKE THIS
AFTERNOON AND EVENING...PLEASE KEEP ABREAST OF THE LATEST WEATHER
INFORMATION AND BE PREPARED TO SEEK SAFE HARBOR QUICKLY SHOULD
STRONGER STORMS APPROACH. WINDS GENERALLY LIGHT SOUTHERLY THIS
MORNING...TRENDING WEST TO SOUTHWESTERLY 5 TO 15 KNOTS THIS
AFTERNOON AND EVENING OUTSIDE ANY STORMS.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
MARINE...JMG
CLIMATE...JMG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
613 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK UPPER DISTURBANCE OVER THE EASTERN CAROLINAS ALONG WITH A
WARM AND HUMID AIR MASS OVER THE REGION WILL BRING ISOLATED SHOWERS
AND THUNDERSTORMS THIS EVENING. A WEAK INLAND TROUGH WILL RESIDE
OVER THE INTERIOR THURSDAY AND INTO THE WEEKEND. A FRONTAL
BOUNDARY WILL STALL ACROSS THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 6:10 PM WEDNESDAY...STRONGEST CONVECTION HAS EXITED THE
FORECAST AREA TO THE SOUTH...WITH SOME MODERATE THUNDERSTORMS
LINGERING OVER EXTREME SOUTHERN GEORGETOWN AND WILLIAMSBURG
COUNTIES. HAVE TWEAKED FORECAST TO ADJUST POPS...OTHERWISE
FORECAST REMAINS ON TRACK AS PER DISCUSSION BELOW:
PLENTY OF HEAT AND HUMIDITY ABOUNDS ACROSS THE AREA WITH THE
STRONGEST CONVECTION ISOLATED OVER CENTRAL AND WESTERN NORTH
CAROLINA. WEAK SUBSIDENCE WAS APPARENTLY AT WORK OVER VERY EASTERN
NORTH CAROLINA...WITH ANVIL DEBRIS CLOUDS BEGINNING TO CUT DOWN ON
SURFACE HEATING ACROSS OUR NE ZONES AT PRESENT. SHOWERS AND TSTMS
WERE FIRING ALONG THE SEA BREEZE FRONT ACROSS EASTERN SC WHERE
CONVECTIVE INHIBITION WAS A BIT WEAKER. STEERING WINDS WILL PUSH
TSTMS GENERALLY TOWARD THE SOUTHWEST THROUGH THE AFTERNOON AND
EVENING HOURS. AN ISOLATED THREAT REMAINS FOR THE STRONGER CELLS
TO GENERATE DAMAGING WIND GUSTS AND LARGE HAIL. THE STORM THAT
MOVED WEST ACROSS RICHMOND AND ANSON COUNTIES EARLIER MANAGED TO
TOPPLE TREES AND DROP 1 INCH HAILSTONES.
TRAINING OF CELLS ALONG THE SEA BREEZE WILL BE POSSIBLE OVER THE
INTERIOR OF GEORGETOWN COUNTY THROUGH AFTERNOON...POSING A LOW-END
THREAT OF LOCALIZED FLOODING.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 230 PM WEDNESDAY...H5 RIDGE AXIS WILL SPRAWL FROM THE
MID-ATLANTIC WESTWARD ACROSS THE CENTRAL PLAINS INTO THE WESTERN
UNITED STATES THURSDAY. THE ORIENTATION OF THE RIDGE WILL SUPPRESS
MOST OF THE SHORT WAVE ENERGY TO CANADA...WITH WEAKER ENERGY
SHIFTING ALONG ITS SOUTHERN PERIPHERY ALONG THE GULF COAST. THE
OVERALL PATTERN BEGINS TO CHANGE DURING FRIDAY AS THE RIDGE
CONSOLIDATES ACROSS THE WESTERN UNITED STATES AND OFF THE EAST COAST
WITH A WEAKNESS EVOLVING ACROSS THE MS VALLEY AND EASTERN UNITED
STATES. LIFT WILL REMAIN LACKING DURING THE SHORT TERM PERIOD WITH
THE SEA BREEZE AS THE MAIN CULPRIT ALONG WITH WEAK INLAND TROUGHING.
AS A RESULT...CAN/T ENTIRELY RULE OUT AN ISOLATED SHRA/TSRA OR
WIDELY SCATTERED STORMS EACH DAY. A BLEND OF MAV/MET NUMBERS APPEARS
REASONABLE THROUGH THE PERIOD AND THESE TEMPERATURES WHICH ARE VERY
CLOSE TO CLIMO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 230 PM WEDNESDAY...A QUICK UPDATE TO THE EXTENDED FORECAST
THIS AFTERNOON SHOWS MOST GUIDANCE REMAINS CONSISTENT WITH THE MID
LEVEL PATTERN TRANSITIONING FROM A WEAKLY FORCED CLASSIC SUMMER
PATTERN TO MID LEVEL TROUGHING ACROSS THE EAST. THE BIGGEST CHANGE
IN WPC SURFACE PROGS SHOWS THE ASSOCIATED SURFACE FRONT REMAINS TO
THE NORTH OF THE AREA ACROSS THE NC/VA BORDER AND I WOULD NOT BE
SURPRISED TO SEE THE POSITION OF THIS BOUNDARY VACILLATE NORTH TO
SOUTH OVER THE COMING DAYS. REGARDLESS OF POSITION...AN INCREASE IN
POPS IN COVERAGE REMAINS IN THE FORECAST MOST NOTABLY FROM MONDAY
THROUGH THE NEW DAY WEDNESDAY.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...THE INTERACTION OF AN UPPER IMPULSE WITH SEA BREEZE AND
MESOSCALE SFC BOUNDARIES SHOULD RESULT IN SCATTERED SHOWERS/T-STORMS
THIS AFTN. CONVECTIVE ACTIVITY MAY BE FOCUSED MORE OVER THE SOUTHERN
TERMS...KFLO/KMYR/KCRE...WHERE BETTER SFC HEATING IS OCCURRING. THE
LATEST HRRR RUNS FAVOR THIS SOLUTION...SO WILL INCLUDE VCTS FOR
THESE TERMS THRU THE AFTN HOURS. VFR WILL PREVAIL TODAY WITH THE
POSSIBILITY OF TEMPO MVFR/IFR IN STORMS. THE WINDS WILL BECOME
LIGHT/CALM OVERNIGHT...BUT RESIDUAL LOW/MID-LEVEL MOISTURE MAY
SOMEWHAT INHIBIT FOG FORMATION. WILL STILL INCLUDE MVFR VSBYS AT ALL
TERMS EARLY THURSDAY...WITH THE BEST CHANCES FOR IFR FOG INLAND AT
KFLO AND KLBT.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:10 PM WEDNESDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS BELOW:
LIGHT WINDS AND LOW SEA-HEIGHTS WILL POSE LITTLE HAZARD FOR
MARINERS THROUGH THE NEAR TERM PERIOD. ISOLATED TSTMS HOWEVER WILL
REMAIN POSSIBLE AS STEERING WINDS ALOFT POTENTIALLY GUIDE A FEW
STORMS OVER THE NEAR-SHORE WATERS. SEAS OF AROUND 2 FEET WILL BE
COMPOSED OF SE WAVES 1-2 FEET EVERY 7-8 SECONDS ACCOMPANIED A
LIGHT SSW CHOP. WINDS AND SEAS WILL BE NOTABLY HIGHER IN AND NEAR
TSTMS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 230 PM WEDNESDAY...INLAND TROUGH WILL PROMOTE W-SW FLOW ACROSS
THE COASTAL WATERS EARLY THURSDAY...THEN THE WIND WILL BACK TO S TO
SW AS THE TROUGH DRIFTS WEST AND THE SEA BREEZE PUSHES INLAND.
SOUTHWESTERLY FLOW WILL PREVAIL THURSDAY NIGHT THROUGH FRIDAY NIGHT
WITH BERMUDA HIGH PRESSURE OFF THE COAST AND WEAK INLAND TROUGH. THE
WIND SPEED WILL UNDULATE EACH DAY...WITH SPEEDS GENERALLY 15 KNOTS
OR LESS THROUGH THE PERIOD AND SEAS WILL AVERAGE 3 FT
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 230 PM WEDNESDAY...SOUTHWEST FLOW OF 10-15 KNOTS SATURDAY WILL
INCREASE TO 15-20 KNOTS SUNDAY AS THE GRADIENT INCREASES. LOW LEVEL
WIND FIELDS DECREASE SLIGHTLY MONDAY AS THE APPROACHING FRONT
WEAKENS. SEAS COULD STILL REACH SCEC CRITERIA LATE SUNDAY BASED ON
THE INCREASE IN WINDS...OTHERWISE...2-4 FEET WILL PREVAIL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
230 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK UPPER DISTURBANCE OVER THE EASTERN CAROLINAS ALONG WITH A
WARM AND HUMID AIR MASS OVER THE REGION...WILL BRING SCATTERED
SHOWERS AND THUNDERSTORMS TODAY. A WEAK INLAND TROUGH WILL RESIDE
OVER THE INTERIOR THURSDAY INTO THE WEEKEND. A FRONTAL BOUNDARY WILL
STALL ACROSS THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM WEDNESDAY...PLENTY OF HEAT AND HUMIDITY ABOUNDS ACROSS
THE AREA WITH THE STRONGEST CONVECTION ISOLATED OVER CENTRAL AND
WESTERN NORTH CAROLINA. WEAK SUBSIDENCE WAS APPARENTLY AT WORK OVER
VERY EASTERN NORTH CAROLINA...WITH ANVIL DEBRIS CLOUDS BEGINNING TO
CUT DOWN ON SURFACE HEATING ACROSS OUR NE ZONES AT PRESENT. SHOWERS
AND TSTMS WERE FIRING ALONG THE SEA BREEZE FRONT ACROSS EASTERN SC
WHERE CONVECTIVE INHIBITION WAS A BIT WEAKER. STEERING WINDS WILL
PUSH TSTMS GENERALLY TOWARD THE SOUTHWEST THROUGH THE AFTERNOON AND
EVENING HOURS. AN ISOLATED THREAT REMAINS FOR THE STRONGER CELLS TO
GENERATE DAMAGING WIND GUSTS AND LARGE HAIL. THE STORM THAT MOVED
WEST ACROSS RICHMOND AND ANSON COUNTIES EARLIER MANAGED TO TOPPLE
TREES AND DROP 1 INCH HAILSTONES.
TRAINING OF CELLS ALONG THE SEA BREEZE WILL BE POSSIBLE OVER THE
INTERIOR OF GEORGETOWN COUNTY THROUGH AFTERNOON...POSING A LOW-END
THREAT OF LOCALIZED FLOODING.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 230 PM WEDNESDAY...H5 RIDGE AXIS WILL SPRAWL FROM THE
MID-ATLANTIC WESTWARD ACROSS THE CENTRAL PLAINS INTO THE WESTERN
UNITED STATES THURSDAY. THE ORIENTATION OF THE RIDGE WILL SUPPRESS
MOST OF THE SHORT WAVE ENERGY TO CANADA...WITH WEAKER ENERGY
SHIFTING ALONG ITS SOUTHERN PERIPHERY ALONG THE GULF COAST. THE
OVERALL PATTERN BEGINS TO CHANGE DURING FRIDAY AS THE RIDGE
CONSOLIDATES ACROSS THE WESTERN UNITED STATES AND OFF THE EAST COAST
WITH A WEAKNESS EVOLVING ACROSS THE MS VALLEY AND EASTERN UNITED
STATES. LIFT WILL REMAIN LACKING DURING THE SHORT TERM PERIOD WITH
THE SEA BREEZE AS THE MAIN CULPRIT ALONG WITH WEAK INLAND TROUGHING.
AS A RESULT...CAN/T ENTIRELY RULE OUT AN ISOLATED SHRA/TSRA OR
WIDELY SCATTERED STORMS EACH DAY. A BLEND OF MAV/MET NUMBERS APPEARS
REASONABLE THROUGH THE PERIOD AND THESE TEMPERATURES WHICH ARE VERY
CLOSE TO CLIMO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 230 PM WEDNESDAY...A QUICK UPDATE TO THE EXTENDED FORECAST
THIS AFTERNOON SHOWS MOST GUIDANCE REMAINS CONSISTENT WITH THE MID
LEVEL PATTERN TRANSITIONING FROM A WEAKLY FORCED CLASSIC SUMMER
PATTERN TO MID LEVEL TROUGHING ACROSS THE EAST. THE BIGGEST CHANGE
IN WPC SURFACE PROGS SHOWS THE ASSOCIATED SURFACE FRONT REMAINS TO
THE NORTH OF THE AREA ACROSS THE NC/VA BORDER AND I WOULD NOT BE
SURPRISED TO SEE THE POSITION OF THIS BOUNDARY VACILLATE NORTH TO
SOUTH OVER THE COMING DAYS. REGARDLESS OF POSITION...AN INCREASE IN
POPS IN COVERAGE REMAINS IN THE FORECAST MOST NOTABLY FROM MONDAY
THROUGH THE NEW DAY WEDNESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...THE INTERACTION OF AN UPPER IMPULSE WITH SEA BREEZE AND
MESOSCALE SFC BOUNDARIES SHOULD RESULT IN SCATTERED SHOWERS/T-STORMS
THIS AFTN. CONVECTIVE ACTIVITY MAY BE FOCUSED MORE OVER THE SOUTHERN
TERMS...KFLO/KMYR/KCRE...WHERE BETTER SFC HEATING IS OCCURRING. THE
LATEST HRRR RUNS FAVOR THIS SOLUTION...SO WILL INCLUDE VCTS FOR
THESE TERMS THRU THE AFTN HOURS. VFR WILL PREVAIL TODAY WITH THE
POSSIBILITY OF TEMPO MVFR/IFR IN STORMS. THE WINDS WILL BECOME
LIGHT/CALM OVERNIGHT...BUT RESIDUAL LOW/MID-LEVEL MOISTURE MAY
SOMEWHAT INHIBIT FOG FORMATION. WILL STILL INCLUDE MVFR VSBYS AT ALL
TERMS EARLY THURSDAY...WITH THE BEST CHANCES FOR IFR FOG INLAND AT
KFLO AND KLBT.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM WEDNESDAY...LIGHT WINDS AND LOW SEA-HEIGHTS WILL POSE
LITTLE HAZARD FOR MARINERS THROUGH THE NEAR TERM PERIOD. ISOLATED
TSTMS HOWEVER WILL REMAIN POSSIBLE AS STEERING WINDS ALOFT
POTENTIALLY GUIDE A FEW STORMS OVER THE NEAR-SHORE WATERS. SEAS OF
AROUND 2 FEET WILL BE COMPOSED OF SE WAVES 1-2 FEET EVERY 7-8
SECONDS ACCOMPANIED A LIGHT SSW CHOP. WINDS AND SEAS WILL BE NOTABLY
HIGHER IN AND NEAR TSTMS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 230 PM WEDNESDAY...INLAND TROUGH WILL PROMOTE W-SW FLOW ACROSS
THE COASTAL WATERS EARLY THURSDAY...THEN THE WIND WILL BACK TO S TO
SW AS THE TROUGH DRIFTS WEST AND THE SEA BREEZE PUSHES INLAND.
SOUTHWESTERLY FLOW WILL PREVAIL THURSDAY NIGHT THROUGH FRIDAY NIGHT
WITH BERMUDA HIGH PRESSURE OFF THE COAST AND WEAK INLAND TROUGH. THE
WIND SPEED WILL UNDULATE EACH DAY...WITH SPEEDS GENERALLY 15 KNOTS
OR LESS THROUGH THE PERIOD AND SEAS WILL AVERAGE 3 FT
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 230 PM WEDNESDAY...SOUTHWEST FLOW OF 10-15 KNOTS SATURDAY WILL
INCREASE TO 15-20 KNOTS SUNDAY AS THE GRADIENT INCREASES. LOW LEVEL
WIND FIELDS DECREASE SLIGHTLY MONDAY AS THE APPROACHING FRONT
WEAKENS. SEAS COULD STILL REACH SCEC CRITERIA LATE SUNDAY BASED ON
THE INCREASE IN WINDS...OTHERWISE...2-4 FEET WILL PREVAIL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...SRP
LONG TERM...SHK
AVIATION...BJR/MJC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
100 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK UPPER DISTURBANCE OVER THE EASTERN CAROLINAS ALONG WITH
A WARM AND HUMID AIR MASS OVER THE REGION...WILL BRING SCATTERED
SHOWERS AND THUNDERSTORMS TODAY. A WEAK INLAND TROUGH WILL RESIDE
OVER THE INTERIOR THURSDAY INTO THE WEEKEND. A FRONTAL BOUNDARY
WILL STALL ACROSS THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...AN OUTFLOW BOUNDARY FROM AN EARLY MORNING
THUNDERSTORM COMPLEX WILL RESULT IN ISOLATED TO SCATTERED CONVECTION
OVER THE NC ZONES THROUGH THE MORNING HOURS. AFTERNOON HEATING WILL
SHIFT THE FOCUS TO RE-NEWED CONVECTION AS A WEAK SURFACE TROUGH
AND A STRENGTHENING SEA BREEZE INTERACT. PWAT VALUES OF 1.85 INCHES
AND VERY HIGH COLUMN BUOYANCY WILL MAKE FOR ACTIVE CONVECTION DURING
THE PEAK IN SURFACE HEATING LATER TODAY. THE STEERING FLOW WILL
GUIDE CONVECTION GENERALLY SOUTHWARD TODAY...GIVING COASTAL LOCALS
A SHOT AT STORMS AS WELL. SOME STORMS WILL BE CAPABLE OF DAMAGING
WINDS BUT SHOULD REMAIN ISOLATED IN NATURE. THE SEA BREEZE MAY
REMAIN RELATIVELY CLOSE TO THE COAST GIVEN THE NW WIND FLOW IN THE
BOUNDARY LAYER. A FAIRLY FLAT SURFACE PRESSURE PATTERN WILL KEEP
SYNOPTIC WINDS LIGHT AND ALLOW A GOOD WARM UP EVEN AT THE COAST AS
AN UPPER RIDGE MAINTAINS AN INFLUENCE ON THE REGION.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...BERMUDA HIGH WILL EXPAND INTO OUR AREA
FROM THE EAST WHILE RIDGE IN THE MID TO UPPER LEVELS WEAKENS AND
GETS PUSHED EAST BY DIGGING TROUGH. BASICALLY THERE WILL BE ENOUGH
SUBSIDENCE AND DRY AIR IN THE MID TO UPPER LEVELS TO ALLOW FOR
ONLY ISOLATED AND LOCALIZED SHOWER ACTIVITY THROUGH MUCH OF THE
PERIOD. THE FOCUS OF CONVECTION WILL BE ALONG SEA BREEZE BOUNDARY
AND FURTHER INLAND ALONG PIEDMONT TROUGH. THE INCREASING SOUTHERLY
COMPONENT TO THE WIND WILL HELP GUIDE ANY STORMS FROM SOUTH TO
NORTH. THE MODELS AREA SHOWING AN AREA OF MUCH DRIER AIR MOVING
OVER THE CAROLINAS LATE THURS INTO FRIDAY WITH VALUES DOWN AS LOW
AS 1.4 INCHES. BY LATE FRI INTO EARLY SAT THE VALUES SHOOT BACK UP
TO CLOSE TO 2 INCHES.
OVERALL WARM AND HUMID SUMMERTIME WEATHER WILL PREVAIL WITH RETURN
FLOW AROUND BERMUDA HIGH. THIS WILL KEEP TEMPS AT OR ABOVE
NORMAL...ESPECIALLY OVERNIGHT WITH TEMPS RUNNING IN THE LOWER 70S
MOST PLACES. DAYTIME HIGH TEMPS WILL BE WITHIN A FEW DEGREES OF
90. THE COMBINATION OF VERY WARM TEMPS AND HIGH HUMIDITY WILL MAKE
IT FEEL AS IF TEMPS WILL BE OVER 100 DEGREES EACH AFTERNOON FOR A
FEW HOURS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 400 AM WEDNESDAY...DEEP SOUTHERLY RETURN FLOW WILL INCREASE AS
MID TO UPPER TROUGH DIGS DOWN FROM THE GREAT LAKES INTO THE
TENNESSEE VALLEY THROUGH THE WEEKEND. THIS WILL PUSH A COLD FRONT
INTO THE CAROLINAS BY LATE SUNDAY. INITIALLY THE GRADIENT WILL
TIGHTEN BETWEEN A MORE PRONOUNCED PIEDMONT TROUGH AND BERMUDA HIGH
BUT THIS WILL BE FURTHER ENHANCED AS FRONT APPROACHES FROM THE
NORTHWEST. WE WILL LOSE THE SUBSIDENCE AND DRIER AIR THROUGH THE
MID LEVELS GIVING WAY TO A GREATER CHC OF CONVECTION THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. THE GFS SHOWS A MINOR PERTURBATION
RIDING UP THROUGH THE AREA IN THE SW FLOW ON SAT AFTN AND THEN THE
MAIN TROUGH APPROACHES LATE SUN INTO MON. THE ACTUAL BOUNDARY
LOOKS LIKE IT WILL WEAKEN AS IT MOVES TOWARD THE AREA WITHOUT
ACTUALLY MAKING IT THROUGH BUT IT WILL SEE INCREASED CONVECTIVE
ACTIVITY ALONG AND AHEAD OF IT THROUGH EARLY NEXT WEEK IN A VERY
MOIST AND MORE UNSTABLE ATMOSPHERE. THE WINDS WILL INCREASE OUT
OF THE SW TO WEST STEERING THE CONVECTION TOWARD THE COAST.
OVERALL EXPECT A MORE ACTIVE PERIOD SUNDAY THROUGH TUES.
WARM AND HUMID WEATHER CONTINUES WITH TEMPS REMAINING RIGHT AROUND
NORMAL WITH OVERNIGHT LOWS ON THE WARM SIDE. TEMPS MAY BE MODIFIED
BY DAILY CONVECTION AND CLOUDS IN A MORE ACTIVE PERIOD OF
CONVECTION...ESPECIALLY LATE SUNDAY THROUGH MONDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
AS OF 18Z...THE INTERACTION OF AN UPPER IMPULSE WITH SEA BREEZE AND
MESOSCALE SFC BOUNDARIES SHOULD RESULT IN SCATTERED SHOWERS/T-STORMS
THIS AFTN. CONVECTIVE ACTIVITY MAY BE FOCUSED MORE OVER THE SOUTHERN
TERMS...KFLO/KMYR/KCRE...WHERE BETTER SFC HEATING IS OCCURRING. THE
LATEST HRRR RUNS FAVOR THIS SOLUTION...SO WILL INCLUDE VCTS FOR
THESE TERMS THRU THE AFTN HOURS. VFR WILL PREVAIL TODAY WITH THE
POSSIBILITY OF TEMPO MVFR/IFR IN STORMS. THE WINDS WILL BECOME
LIGHT/CALM OVERNIGHT...BUT RESIDUAL LOW/MID-LEVEL MOISTURE MAY
SOMEWHAT INHIBIT FOG FORMATION. WILL STILL INCLUDE MVFR VSBYS AT ALL
TERMS EARLY THURSDAY...WITH THE BEST CHANCES FOR IFR FOG INLAND AT
KFLO AND KLBT.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...SOMEWHAT VARIABLE WINDS ARE EXPECTED TODAY
AND TONIGHT UNDER A BIT OF A WEAK GRADIENT. EXPECT LIGHT W TO NW
WINDS THIS MORNING TO BECOME SE TO S THIS AFTERNOON THEN S TO SW
TONIGHT. SPEEDS LOOK TO BE 10 KT OR LESS WITH SEAS AROUND 2 FT.
SEAS COMPRISED OF SE WAVES 2 FEET AT 7-8 SECONDS WITH ONLY LIGHT
CHOP ANTICIPATED...AND MOSTLY NEAR SHORE IN THE AFTERNOON. TSTMS
MAY IMPACT THE WATERS TODAY AND TONIGHT...WITH STEERING WINDS
GUIDING ANY STORMS THAT DEVELOP FROM THE NORTH TO THE SOUTH.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...BERMUDA HIGH TAKES HOLD AS IT EXPANDS
WESTWARD OVER LOCAL WATERS. THIS WILL PRODUCE A SOUTHERLY RETURN
FLOW THROUGH THE PERIOD. THURSDAY WILL START OUT WITH LIGHTER FLOW
OF 10 KTS OR SO BUT AS GRADIENT TIGHTENS BETWEEN PIEDMONT TROUGH
OF INLAND CAROLINAS AND BERMUDA HIGH...WIND WILL INCREASE OUT OF
THE SOUTH THROUGH LATE FRI INTO SAT. THE PERSISTENT AND INCREASING
SOUTHERLY FLOW WILL PUSH SEAS UP FROM 2 TO 3 FT THURS INTO FRI TO
3 TO 5 FT BY FRI NIGHT AND POSSIBLY TOPPING SCA THRESHOLDS BY SAT
MORNING. WINDS WILL BE GUSTY AND HIGHER EACH AFTERNOON IN SEA
BREEZE.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 400 AM WEDNESDAY...INCREASING AND PERSISTENT SOUTHERLY FLOW
AROUND BERMUDA HIGH WILL DRIVE SEAS UP TOWARD SCA THRESHOLDS EARLY
SATURDAY. THE GRADIENT WILL REMAIN TIGHT THROUGH SATURDAY INTO
SUNDAY AS COLD FRONT APPROACHES THE CAROLINAS FROM THE NORTHWEST
AND PIEDMONT TROUGH REMAINS ACROSS INLAND CAROLINAS. THE WINDS
INITIALLY WILL BE 15 KTS OR LESS BUT WILL INCREASE UP TO 15 TO 20
KTS...ESPECIALLY IN THE OUTER WATERS THROUGH SATURDAY INTO SUNDAY.
THIS INCREASING SOUTHERLY PUSH WILL KEEP SEAS UP RIGHT AROUND
ADVISORY LEVELS...NEAR 6 FT IN OUTER WATERS AND 3 TO 5 ELSEWHERE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...8
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...BJR/8
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1008 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 942 PM CDT THU JUL 18 2013
UPDATE TO REDUCE LATE EVENING POPS AND CONFINE AREA FROM THE
TURTLE MOUNTAINS THROUGH FOSTER COUNTY. STRONG STORMS GLANCED THE
FAR NORTHEAST EARLIER THIS EVENING BUT HAVE SINCE DISSIPATED WHILE
CONVECTION CONTINUES TO THE EAST. CANNOT RULE OUT AN ISOLATED
STORM OVER THE NEXT FEW HOURS...BUT THE PROBABILITY IS LOW.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE MAIN FORECAST CONCERN FOR THE PERIOD WILL BE THUNDERSTORM
CHANCES THIS AFTERNOON AND EVENING AS WELL AS THE SEVERE POTENTIAL.
HEAT INDEX VALUES APPROACHING 100 DEGREES WILL CONTINUE ACROSS THE
SOUTHERN JAMES RIVER BASIN AHEAD OF A COLD FRONT THROUGH THE LATE
AFTERNOON. THEREFORE...WILL MAINTAIN THE CURRENT HEAT ADVISORY IN
EFFECT THROUGH 00Z.
IN ADDITION...THUNDERSTORMS ARE STILL PROGGED TO DEVELOP OVER THE
JAMES RIVER BASIN IN AN AREA OF LARGE INSTABILITY CHARACTERIZED BY
SURFACE-BASED CAPE VALUES OF 2500 J/KG. HOWEVER...MARGINAL TO LOW
DEEP LAYER SHEAR IS EXPECTED TO KEEP THIS CONVECTION BELOW SEVERE
LIMITS. THIS ACTIVITY SHOULD BE OUT OF THE JAMES RIVER BASIN BY 00Z
THIS EVENING AS THE COLD FRONT PUSHES EAST OF THE CWA.
AN UPPER WAVE OVER NORTHWESTERN NORTH DAKOTA WILL PIVOT ACROSS THE
STATE TONIGHT. ONGOING CONVECTION OVER THE SOUTHERN CANADIAN PRAIRIES
IS EXPECTED TO ENTER NORTH CENTRAL NORTH DAKOTA AFTER 23Z AS THE
WAVE PIVOTS ACROSS THE REGION. THE 3KM HRRR AND 12Z WRF KEEP THE
CONVECTION CONFINED TO AREAS NORTHEAST OF HIGHWAY 52 THROUGH 03Z.
SOME STORMS MIGHT ALREADY BE SEVERE AS THEY CROSS THE BORDER.
HOWEVER...THE SEVERE THREAT SHOULD DIMINISH AFTER 03Z WITH THE LOSS
OF DAYTIME HEATING. WILL THEREFORE INTRODUCE SEVERE WORDING IN THE
GRIDS FOR THE 23Z-03Z PERIOD FOR POINTS NORTH OF A LINE FROM MOHALL
TO DEERING TO BALTA. FURTHERMORE...WILL CONTINUE TO HIGHLIGHT THIS
THREAT IN THE HWO. AFTER 03Z...DRY CONDITIONS ARE EXPECTED AREAWIDE
AS HIGH PRESSURE BUILDS INTO THE REGION. MUCH COOLER OVERNIGHT LOWS
ARE EXPECTED WITH READINGS FROM THE MID 50S WEST TO THE LOWER 60S
SOUTHEAST.
FOR FRIDAY...HIGH PRESSURE WILL SLOWLY SINK SOUTHWARD INTO SOUTH
DAKOTA. AS IT DOES...A WEAK BAROCLINIC ZONE IS PROGGED TO SET UP
OVER NORTHERN NORTH DAKOTA. THIS FEATURE SHOULD PROVIDE FOCUS FOR
AFTERNOON CONVECTION. GIVEN THE ELEVATED NATURE OF THE THUNDERSTORM
POTENTIAL...THINK ANY CONVECTION THAT DOES DEVELOP WILL STAY BELOW
SEVERE LIMITS. TEMPERATURES WILL BE MORE SEASONAL FRIDAY WITH HIGHS
FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A NORTHWEST UPPER
LEVEL FLOW PATTERN WITH PERIODIC EMBEDDED SHORTWAVES MOVING THROUGH
THE FLOW. AT THIS TIME THE LONG TERM MODELS ARE DEPICTING SHORTWAVES
MOVING THROUGH THE FORECAST AREA EACH DAY...KEEPING ISOLATED TO
SCATTERED THUNDERSTORM ACTIVITY/CHANCES EACH DAY.
THE LONG TERM BEGINS FRIDAY NIGHT WITH ANOTHER SURFACE COLD FRONT
MOVING SOUTHWARD DURING THE DAYTIME FRIDAY...BECOMING STATIONARY
FRIDAY NIGHT/SATURDAY AS DRY HIGH PRESSURE MOVES INTO NORTHEASTERN
NORTH DAKOTA. EXPECT SCATTERED THUNDERSTORMS ALONG THIS BOUNDARY
FROM NORTHWEST TO SOUTH CENTRAL/SOUTHEASTERN NORTH DAKOTA. PLENTY OF
CAPE BUT LIMITED SHEAR WILL KEEP THE MENTION OF SEVERE STORMS OUT OF
THE FORECAST.
THE NEXT CHANCE OF SCATTERED THUNDERSTORMS APPEARS TO BE SUNDAY
AFTERNOON/NIGHT...THEN AGAIN MONDAY AFTERNOON/NIGHT. AT THIS TIME IT
APPEARS THAT WEDNESDAY MAY SEE A BREAK IN THE ACTION WITH DRY
SURFACE HIGH PRESSURE DEPICTED AND A LULL IN THE SHORTWAVES ACROSS
NORTH DAKOTA...BUT TIMING IS VERY IFFY WITH TIMING OF SHORTWAVES.
ANOTHER SHORTWAVE WITH A SURFACE TROUGH/FRONT TRAVERSES THE FORECAST
AREA THURSDAY.
THUS ISOLATED TO SCATTERED THUNDERSTORMS NEARLY EACH DAY. THE
COOLEST DAY SHOULD BE SATURDAY WITH HIGHS FROM THE 70S ALONG AND
NORTH AND EAST OF THE MISSOURI RIVER WITH LOW TO MID 80S SOUTH AND
WEST OF THE RIVER. OTHERWISE SEASONABLE TEMPERATURES WITH HIGHS
MAINLY IN THE 80S AND LOWS IN THE UPPER 50S TO MID 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 942 PM CDT THU JUL 18 2013
UPDATED WINDS AT KMOT TO EXTEND GUSTS TO 30 KTS AS TIGHT PRESSURE
GRADIENT WILL PERSIST FOR A FEW MORE HOURS. OTHERWISE VFR
CONDITIONS THROUGH THE PERIOD. MAINTAINED VCTS GROUP AT KMOT AT
17Z FRIDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RK
SHORT TERM...TM
LONG TERM...JV
AVIATION...RK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
945 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 945 PM CDT THU JUL 18 2013
CONVECTION STRUGGLED ALL EVENING TO GET GOING ACROSS EASTERN FA
ALONG PREFRONTAL TROUGH/WARM FRONT. ABOVE BOUNDARY CLOSE TO EXITING FA
TO THE EAST AND NOW CONFINED TO HUBBARD/BELTRAMI COUNTY. TRIMMED
BACK ON POPS THIS AREA. FARTHER NORTHWEST MORE ROBUST BUT WIDELY
SCATTERED CONVECTION CONTINUES ALONG INTERNATIONAL BORDER AREA
ASSOCIATED WITH SECONDARY BOUNDARY AND MID LEVEL WAVE RIDING ALONG
INTERNATIONAL BORDER. HAVE HIGHEST POPS ALONG INTERNATIONAL BORDER
INTO EARLY AM AS FEATURE CONTINUES TO PROPAGATE EAST IN
MODERATELY UNSTABLE AIR MASS. ELSEWHERE ADJUSTED POPS ACCORDINGLY
BASED ON CURRENT RADAR TRENDS. REMAINDER OF FORECAST UNCHANGED FOR
THIS UPDATE.
UPDATE ISSUED AT 645 PM CDT THU JUL 18 2013
DEEP CONVECTION BECOMING A LITTLE BETTER ORGANIZED ALONG FRONTAL
BOUNDARY FROM NEAR FSE NE TO INL. SO FAR CELLS HAVE REMAINED BLO
SVR LIMITS HOWEVER WILL CONTINUE TO MONITOR. FARTHER NW ISOLD
SHRA/TSRA CLOSING IN ON FAR NW FA HOWEVER STRONGER STORMS STILL
WELL NORTH OF INL BORDER AND CONFIDENCE NOT VERY HIGH ON SEVERE
POTENTIAL THIS AREA. FOR NOW WITH STRENGTH OF MID LEVEL IMPULSE
AND DEGREE OF INSTABILITY CANNOT RULE OUT ISLD STRONG STORM SO
WILL MAINTAIN STRONGER STORM WORDING THIS AREA. MADE SOME MINOR
POP ADJUSTMENTS THROUGH MID EVENING TRYING TO FINE TUNE AREAS FOR
BEST STORM POTENTIAL ACROSS N CENTRAL MN. PULLED POPS ACROSS
CENTRAL FA IN BETWEEN BOUNDARIES WHERE CONVECTION NOT ANTICIPATED.
TEMPERATURES STILL WARM/HUMID BUT BLO HEAT ADVISORY CRITERIA SO WILL
ALLOW TO EXPIRE ON TIME. ANY OTHER CHANGES MINIMAL THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 250 PM CDT THU JUL 18 2013
SEVERE POTENTIAL THIS EVENING WILL BE THE MAIN CONCERN. HEAT
ADVISORY CONDITIONS ACROSS THE SOUTHERN FA WILL CONTINUE INTO THE
EARLY EVENING HOURS. THE MAIN SEVERE RISK AREA WILL BE ALONG THE
WARM FRONT FROM JUST EAST OF GRAND FORKS INTO BEMIDJI...AND
LOCATIONS 50 MILES NORTH AND SOUTH OF THIS LINE. SPC SUPERCELL
COMPOSITE AND SIGNIFICANT TORNADO PARAMETERS INDICATE THIS AREA
WITH THE GREATEST POTENTIAL. 19Z LAPS ANALYSIS STILL INDICATES A
STRONG CAP (MLCIN AOA 40 J/KG)...AND NOT SURE HOW WIDESPREAD
INITIATION WILL BE. HRRR HAS BEEN CONSISTENT WITH DEVELOPING
STORMS...AND WILL CONTINUE TO FOLLOW ITS COVERAGE AND INITIATION
TIMES. ANTICIPATE SUPERCELL STORMS CAPABLE OF ALL MODES OF SEVERE
WEATHER. THERE IS ANOTHER AREA OF CONCERN ACROSS THE NW FA AS THE
UPPER WAVE APPROACHES THIS EVENING. AN AREA OF STORMS HAS
DEVELOPED WELL TO THE NW IN SASKATCHEWAN (JUST AHEAD OF THE UPPER
WAVE)...AND INSTABILITY SHOULD INCREASE JUST AHEAD OF THIS
COMPLEX. THIS COMPLEX MAY STILL BE SEVERE AS IT MOVES INTO THE NW
FA...AND QUICKLY WEAKEN BY MIDNIGHT.
FRIDAY-FRIDAY NIGHT...ANOTHER COLD FRONT WILL MOVE INTO THE REGION
ON FRIDAY. INSTABILITY WILL BE WEAK...BUT SHOULD BE ENOUGH FOR
ISOLD SHOWERS AND POSSIBLY THUNDER FRIDAY AFTERNOON. SFC HIGH
PRESSURE WILL BEGIN WORKING INTO THE REGION FROM THE NE FRIDAY
NIGHT...AND MIN TEMPS BY SATURDAY MORNING SHOULD BE INTO THE 40S
ACROSS NE MN (WARMER TO THE WEST AND SOUTH).
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
SATURDAY-SUNDAY...MODELS AGREE WITH NORTHWEST FLOW ALOFT AND
SURFACE RIDGING ACROSS MUCH OF THE FA. THE SURFACE RIDGE GRADUALLY
SHIFTS BACK TO THE EAST BY SUNDAY. THUNDER CHANCES WILL BE ON THE
WESTERN EDGE OF THE FA ON SATURDAY...AND SHIFT TO THE EAST BY
SUNDAY. FORCING AND INSTABILITY WILL BE WEAK...SO EXPECT ONLY
ISOLD TO SCATTERED ACTIVITY. TEMPERATURES WILL BE BELOW NORMAL
VALUES AS A RELATIVELY COLDER AIRMASS WILL BE ACROSS THE REGION.
SUNDAY NIGHT-THURSDAY...LONG TERM MODELS ARE IN POOR AGREEMENT.
IN GENERAL...ECMWF TRACK OF SFC LOWS TRANSITING SOUTHERN CANADA
NEXT WEEK ARE MUCH FURTHER NORTH THAN THE GFS...WHICH BRINGS THEM
ACROSS NORTHERN TIER OF CONUS. ECMWF ALSO CONTINUES TO PRODUCE A
LOT OF QPF...WHICH SEEMS UNREALISTIC. THEY DO AGREE SOMEWHAT ON A
NW FLOW UPPER AIR PATTERN BUT EVEN THAT DIVERGES BY DAY 6. THUS
LOW POPS IN CONSALL IS A RESULT OF ECMWF BLENDED INTO THE
SOLUTION. CONFIDENCE IS LOW BEYOND DAY 4 (NIGHT). BEST CHANCE
APPEARS TO BE SUN NIGHT INTO MON MORNING...WHEN AN UPPER WAVE
MOVES ACROSS THE AREA. BEST CHANCES WILL BE ACROSS THE NORTHEAST
AND DO HAVE A FAIR DEGREE OF CONFIDENCE FOR 40S POPS ACROSS THE
NORTH. GFS WOULD THEN GIVE US DRY WEATHER MON NIGHT AND I HAVE
REMOVED CHANCE POPS FOR THIS PERIOD. GFS THEN BRINGS ANOTHER SFC
LOW INTO NORTHERN TIER TUE NIGHT...FOR ANOTHER CHANCE OF
SHOWERS/TSTMS ACROSS THE NORTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM CDT THU JUL 18 2013
BASED ON CURRENT RADAR IMAGERY BJI TAF SITE WILL HAVE T POTENTIAL
THROUGH MID/LATE EVENING. CONFIDENCE LOWER AT DVL SO JUST MENTIONED
T VCNTY THIS LOCATION. REMAINDER OF TAF SITES SHOULD BE STORM FREE
WITH VFR CONDITIONS OVERNIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
652 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 645 PM CDT THU JUL 18 2013
DEEP CONVECTION BECOMING A LITTLE BETTER ORGANIZED ALONG FRONTAL
BOUNDARY FROM NEAR FSE NE TO INL. SO FAR CELLS HAVE REMAINED BLO
SVR LIMITS HOWEVER WILL CONTINUE TO MONITOR. FARTHER NW ISOLD
SHRA/TSRA CLOSING IN ON FAR NW FA HOWEVER STRONGER STORMS STILL
WELL NORTH OF INL BORDER AND CONFIDENCE NOT VERY HIGH ON SEVERE
POTENTIAL THIS AREA. FOR NOW WITH STRENGTH OF MID LEVEL IMPULSE
AND DEGREE OF INSTABILITY CANNOT RULE OUT ISLD STRONG STORM SO
WILL MAINTAIN STRONGER STORM WORDING THIS AREA. MADE SOME MINOR
POP ADJUSTMENTS THROUGH MID EVENING TRYING TO FINE TUNE AREAS FOR
BEST STORM POTENTIAL ACROSS N CENTRAL MN. PULLED POPS ACROSS
CENTRAL FA IN BETWEEN BOUNDARIES WHERE CONVECTION NOT ANTICIPATED.
TEMPERATURES STILL WARM/HUMID BUT BLO HEAT ADVISORY CRITERIA SO WILL
ALLOW TO EXPIRE ON TIME. ANY OTHER CHANGES MINIMAL THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 250 PM CDT THU JUL 18 2013
SEVERE POTENTIAL THIS EVENING WILL BE THE MAIN CONCERN. HEAT
ADVISORY CONDITIONS ACROSS THE SOUTHERN FA WILL CONTINUE INTO THE
EARLY EVENING HOURS. THE MAIN SEVERE RISK AREA WILL BE ALONG THE
WARM FRONT FROM JUST EAST OF GRAND FORKS INTO BEMIDJI...AND
LOCATIONS 50 MILES NORTH AND SOUTH OF THIS LINE. SPC SUPERCELL
COMPOSITE AND SIGNIFICANT TORNADO PARAMETERS INDICATE THIS AREA
WITH THE GREATEST POTENTIAL. 19Z LAPS ANALYSIS STILL INDICATES A
STRONG CAP (MLCIN AOA 40 J/KG)...AND NOT SURE HOW WIDESPREAD
INITIATION WILL BE. HRRR HAS BEEN CONSISTENT WITH DEVELOPING
STORMS...AND WILL CONTINUE TO FOLLOW ITS COVERAGE AND INITIATION
TIMES. ANTICIPATE SUPERCELL STORMS CAPABLE OF ALL MODES OF SEVERE
WEATHER. THERE IS ANOTHER AREA OF CONCERN ACROSS THE NW FA AS THE
UPPER WAVE APPROACHES THIS EVENING. AN AREA OF STORMS HAS
DEVELOPED WELL TO THE NW IN SASKATCHEWAN (JUST AHEAD OF THE UPPER
WAVE)...AND INSTABILITY SHOULD INCREASE JUST AHEAD OF THIS
COMPLEX. THIS COMPLEX MAY STILL BE SEVERE AS IT MOVES INTO THE NW
FA...AND QUICKLY WEAKEN BY MIDNIGHT.
FRIDAY-FRIDAY NIGHT...ANOTHER COLD FRONT WILL MOVE INTO THE REGION
ON FRIDAY. INSTABILITY WILL BE WEAK...BUT SHOULD BE ENOUGH FOR
ISOLD SHOWERS AND POSSIBLY THUNDER FRIDAY AFTERNOON. SFC HIGH
PRESSURE WILL BEGIN WORKING INTO THE REGION FROM THE NE FRIDAY
NIGHT...AND MIN TEMPS BY SATURDAY MORNING SHOULD BE INTO THE 40S
ACROSS NE MN (WARMER TO THE WEST AND SOUTH).
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
SATURDAY-SUNDAY...MODELS AGREE WITH NORTHWEST FLOW ALOFT AND
SURFACE RIDGING ACROSS MUCH OF THE FA. THE SURFACE RIDGE GRADUALLY
SHIFTS BACK TO THE EAST BY SUNDAY. THUNDER CHANCES WILL BE ON THE
WESTERN EDGE OF THE FA ON SATURDAY...AND SHIFT TO THE EAST BY
SUNDAY. FORCING AND INSTABILITY WILL BE WEAK...SO EXPECT ONLY
ISOLD TO SCATTERED ACTIVITY. TEMPERATURES WILL BE BELOW NORMAL
VALUES AS A RELATIVELY COLDER AIRMASS WILL BE ACROSS THE REGION.
SUNDAY NIGHT-THURSDAY...LONG TERM MODELS ARE IN POOR AGREEMENT.
IN GENERAL...ECMWF TRACK OF SFC LOWS TRANSITING SOUTHERN CANADA
NEXT WEEK ARE MUCH FURTHER NORTH THAN THE GFS...WHICH BRINGS THEM
ACROSS NORTHERN TIER OF CONUS. ECMWF ALSO CONTINUES TO PRODUCE A
LOT OF QPF...WHICH SEEMS UNREALISTIC. THEY DO AGREE SOMEWHAT ON A
NW FLOW UPPER AIR PATTERN BUT EVEN THAT DIVERGES BY DAY 6. THUS
LOW POPS IN CONSALL IS A RESULT OF ECMWF BLENDED INTO THE
SOLUTION. CONFIDENCE IS LOW BEYOND DAY 4 (NIGHT). BEST CHANCE
APPEARS TO BE SUN NIGHT INTO MON MORNING...WHEN AN UPPER WAVE
MOVES ACROSS THE AREA. BEST CHANCES WILL BE ACROSS THE NORTHEAST
AND DO HAVE A FAIR DEGREE OF CONFIDENCE FOR 40S POPS ACROSS THE
NORTH. GFS WOULD THEN GIVE US DRY WEATHER MON NIGHT AND I HAVE
REMOVED CHANCE POPS FOR THIS PERIOD. GFS THEN BRINGS ANOTHER SFC
LOW INTO NORTHERN TIER TUE NIGHT...FOR ANOTHER CHANCE OF
SHOWERS/TSTMS ACROSS THE NORTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 650 PM CDT THU JUL 18 2013
BASED ON CURRENT RADAR IMAGERY BJI TAF SITE WILL HAVE T POTENTIAL
THROUGH MID/LATE EVENING. CONFIDENCE LOWER AT DVL SO JUST MENTIONED
T VCNTY THIS LOCATION. REMAINDER OF TAF SITES SHOULD BE STORM FREE
WITH VFR CONDITIONS OVERNIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
607 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 554 PM CDT THU JUL 18 2013
UPDATE TO CANCEL HEAT ADVISORY FOR JAMES RIVER VALLEY AND FOR
MINOR ADJUSTMENTS TO POPS TONIGHT ACROSS THE NORTH. SO FAR THROUGH
EARLY EVENING...THE MOST INTENSE STORMS ASSOCIATED WITH A DECENT
SHORT WAVE TROUGH HAVE STAYED NORTH OF THE INTERNATIONAL BORDER.
STILL POTENTIAL FOR STRONG TO SEVERE STORMS TO CLIP THE NORTHEAST
COUNTIES THROUGH LATE EVENING.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE MAIN FORECAST CONCERN FOR THE PERIOD WILL BE THUNDERSTORM
CHANCES THIS AFTERNOON AND EVENING AS WELL AS THE SEVERE POTENTIAL.
HEAT INDEX VALUES APPROACHING 100 DEGREES WILL CONTINUE ACROSS THE
SOUTHERN JAMES RIVER BASIN AHEAD OF A COLD FRONT THROUGH THE LATE
AFTERNOON. THEREFORE...WILL MAINTAIN THE CURRENT HEAT ADVISORY IN
EFFECT THROUGH 00Z.
IN ADDITION...THUNDERSTORMS ARE STILL PROGGED TO DEVELOP OVER THE
JAMES RIVER BASIN IN AN AREA OF LARGE INSTABILITY CHARACTERIZED BY
SURFACE-BASED CAPE VALUES OF 2500 J/KG. HOWEVER...MARGINAL TO LOW
DEEP LAYER SHEAR IS EXPECTED TO KEEP THIS CONVECTION BELOW SEVERE
LIMITS. THIS ACTIVITY SHOULD BE OUT OF THE JAMES RIVER BASIN BY 00Z
THIS EVENING AS THE COLD FRONT PUSHES EAST OF THE CWA.
AN UPPER WAVE OVER NORTHWESTERN NORTH DAKOTA WILL PIVOT ACROSS THE
STATE TONIGHT. ONGOING CONVECTION OVER THE SOUTHERN CANADIAN PRAIRIES
IS EXPECTED TO ENTER NORTH CENTRAL NORTH DAKOTA AFTER 23Z AS THE
WAVE PIVOTS ACROSS THE REGION. THE 3KM HRRR AND 12Z WRF KEEP THE
CONVECTION CONFINED TO AREAS NORTHEAST OF HIGHWAY 52 THROUGH 03Z.
SOME STORMS MIGHT ALREADY BE SEVERE AS THEY CROSS THE BORDER.
HOWEVER...THE SEVERE THREAT SHOULD DIMINISH AFTER 03Z WITH THE LOSS
OF DAYTIME HEATING. WILL THEREFORE INTRODUCE SEVERE WORDING IN THE
GRIDS FOR THE 23Z-03Z PERIOD FOR POINTS NORTH OF A LINE FROM MOHALL
TO DEERING TO BALTA. FURTHERMORE...WILL CONTINUE TO HIGHLIGHT THIS
THREAT IN THE HWO. AFTER 03Z...DRY CONDITIONS ARE EXPECTED AREAWIDE
AS HIGH PRESSURE BUILDS INTO THE REGION. MUCH COOLER OVERNIGHT LOWS
ARE EXPECTED WITH READINGS FROM THE MID 50S WEST TO THE LOWER 60S
SOUTHEAST.
FOR FRIDAY...HIGH PRESSURE WILL SLOWLY SINK SOUTHWARD INTO SOUTH
DAKOTA. AS IT DOES...A WEAK BAROCLINIC ZONE IS PROGGED TO SET UP
OVER NORTHERN NORTH DAKOTA. THIS FEATURE SHOULD PROVIDE FOCUS FOR
AFTERNOON CONVECTION. GIVEN THE ELEVATED NATURE OF THE THUNDERSTORM
POTENTIAL...THINK ANY CONVECTION THAT DOES DEVELOP WILL STAY BELOW
SEVERE LIMITS. TEMPERATURES WILL BE MORE SEASONAL FRIDAY WITH HIGHS
FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A NORTHWEST UPPER
LEVEL FLOW PATTERN WITH PERIODIC EMBEDDED SHORTWAVES MOVING THROUGH
THE FLOW. AT THIS TIME THE LONG TERM MODELS ARE DEPICTING SHORTWAVES
MOVING THROUGH THE FORECAST AREA EACH DAY...KEEPING ISOLATED TO
SCATTERED THUNDERSTORM ACTIVITY/CHANCES EACH DAY.
THE LONG TERM BEGINS FRIDAY NIGHT WITH ANOTHER SURFACE COLD FRONT
MOVING SOUTHWARD DURING THE DAYTIME FRIDAY...BECOMING STATIONARY
FRIDAY NIGHT/SATURDAY AS DRY HIGH PRESSURE MOVES INTO NORTHEASTERN
NORTH DAKOTA. EXPECT SCATTERED THUNDERSTORMS ALONG THIS BOUNDARY
FROM NORTHWEST TO SOUTH CENTRAL/SOUTHEASTERN NORTH DAKOTA. PLENTY OF
CAPE BUT LIMITED SHEAR WILL KEEP THE MENTION OF SEVERE STORMS OUT OF
THE FORECAST.
THE NEXT CHANCE OF SCATTERED THUNDERSTORMS APPEARS TO BE SUNDAY
AFTERNOON/NIGHT...THEN AGAIN MONDAY AFTERNOON/NIGHT. AT THIS TIME IT
APPEARS THAT WEDNESDAY MAY SEE A BREAK IN THE ACTION WITH DRY
SURFACE HIGH PRESSURE DEPICTED AND A LULL IN THE SHORTWAVES ACROSS
NORTH DAKOTA...BUT TIMING IS VERY IFFY WITH TIMING OF SHORTWAVES.
ANOTHER SHORTWAVE WITH A SURFACE TROUGH/FRONT TRAVERSES THE FORECAST
AREA THURSDAY.
THUS ISOLATED TO SCATTERED THUNDERSTORMS NEARLY EACH DAY. THE
COOLEST DAY SHOULD BE SATURDAY WITH HIGHS FROM THE 70S ALONG AND
NORTH AND EAST OF THE MISSOURI RIVER WITH LOW TO MID 80S SOUTH AND
WEST OF THE RIVER. OTHERWISE SEASONABLE TEMPERATURES WITH HIGHS
MAINLY IN THE 80S AND LOWS IN THE UPPER 50S TO MID 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 101 PM CDT THU JUL 18 2013
VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH
DAKOTA. THERE WILL BE A NARROW WINDOW WHERE THUNDERSTORMS COULD
IMPACT KMOT BETWEEN 01Z-03Z. HOWEVER...GIVEN THE LOW CONFIDENCE
IN OCCURRENCE...ONLY INDICATED VCTS AND VFR CONDITIONS IN THE
KMOT TAF.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RK
SHORT TERM...TM
LONG TERM...JV
AVIATION...TM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CDT TUE JUL 16 2013
.UPDATE...
ISSUED AT 1144 PM CDT TUE JUL 16 2013
WILL CONTINUE WITH ISOLD-SCT SHRA/TSRA IN THE ZONE VERY NEAR THE
850 MB FRONT WHERE WEAK CONVERGENCE WILL CONTINUE OVERNIGHT...THIS
REGION RUNS ROUGHLY EITHER SIDE OF HWY 2. HRRR CONTINUES TO
DEVELOP AREA BUT PAST RUNS HAVE BEEN VERY BULLISH FOR THIS EVE AND
THAT DIDNT MATERIALIZE. DO HAVE ONE DECENT STORM BTWN MOT/BIS
MOVING EAST-SOUTHEAST THRU FAR EASTERN MCLEAN CO ND.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 336 PM CDT TUE JUL 16 2013
PCPN CHANCES WILL BE THE MAIN CHALLENGE THROUGHOUT THE ENTIRE
SHORT TERM. NOT SEEING ANY REASON TO DEVIATE TOO MUCH FROM THE
INHERITED FORECAST AT THIS POINT. LATE THIS AFTERNOON SEVERAL
LINES OF SHOWERS/TSTMS HAD FORMED WELL BEHIND THE SFC BOUNDARY.
THE CLOSEST BAND OF SHOWERS/TSTMS RUNS FROM WINNIPEG DOWN THROUGH
THE RUGBY AREA WITH THE OTHERS BACK OVER NORTHWEST ND. THE HIGH
RESOLUTION MODELS DIFFER ON WHERE THEY PLACE THESE SHOWERS/TSTMS
TONIGHT. HOWEVER THEY ALL SEEM TO AGREE WITH THE GENERAL IDEA OF
ISOLATED TO SCATTERED CONVECTION ALONG AND NORTH HIGHWAY 2. THE
SFC BOUNDARY CURRENTLY LIES ALONG A LINE FROM KROX TO JUST NORTH
OF GRAND FORKS TO NEAR KBIS. THIS BOUNDARY IS EXPECTED TO SLOWLY
SAG SOUTHWARD MAYBE ANOTHER 20 MILES OR SO AND EITHER WASH OUT OR
STAGNATE. THE UPPER JET IS EXPECTED TO REMAIN MAINLY NORTH OF THE
CANADIAN BORDER AND MODELS DO NOT SHOW ANY STRONG UPPER LEVEL
DISTURBANCES COMING THROUGH EITHER. HOWEVER WITH MODEST CAPE AND
THE SFC BOUNDARY THERE APPEARS TO BE JUST ENOUGH FORCING. LATEST
SPC DAY1 DISCUSSION MENTIONS A LIMITED SEVERE THREAT DUE TO THE
ABOVE MENTIONED FEATURES. THE WEAK WARM ADVECTION TONIGHT AND NO
REAL FOCUSED LOW LEVEL JET WILL LIKELY LIMIT THE TSTM THREAT
AFTER DARK AS WELL.
FOR WED A WEAK SFC HIGH WILL TRY TO BUILD DOWN INTO THE NORTHERN
FA. DO NOT SEE A LOT OF CHANGE FROM CONDITIONS TODAY WITH THE
WASHED OUT OR STAGNANT SFC BOUNDARY STILL HANGING ACROSS THE
CENTRAL FA AND THE UPPER JET ALONG OR NORTH OF THE CANADIAN
BORDER. FORECAST WILL MAINTAIN THE LOW CHANCES FOR PCPN MAINLY
ALONG AND NORTH OF HIGHWAY 200. SPC DAY2 DISCUSSION MENTIONS THE
POSSIBILITY OF ELEVATED STORMS ON WED NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 336 PM CDT TUE JUL 16 2013
STILL LOOKING LIKE THE BEST CHANCE FOR TSTMS MAY BE ON THU AS THE
SFC LOW LIFTS UP INTO SOUTH CENTRAL ND. WILL UP CHANCES INTO THE
LIKELY CATEGORY FOR NORTHEAST ND INTO NORTHWEST MN. COULD STILL
SOME LOWER CHANCES FOR PCPN THU NIGHT INTO FRI.
FRIDAY NIGHT-TUESDAY...SOME LOW-LEVEL COLD AIR ADVECTION WILL
PERSIST FRIDAY NIGHT INTO SATURDAY AS A CANADIAN HIGH PRESSURE
SYSTEM DROPS SOUTHWARD. A DRY AND COOL JULY AIR MASS IS EXPECTED FOR
THE START OF THE WEEKEND AS 925 MB TEMPS FALL INTO THE 10-15C RANGE
BY SATURDAY MORNING. AS A RESULT...HIGHS ON SATURDAY LOOK TO REMAIN
IN THE UPPER 60S TO MID 70S. LOWS FRIDAY NIGHT AND SATURDAY NIGHT
WILL BE IN THE 50S...WITH SOME UPPER 40S POSSIBLE. TEMPS SHOULD WARM
CLOSER TO AVERAGE BY SUNDAY AS THE SFC HIGH SLIPS EASTWARD.
BEYOND SUNDAY...MODEL DIFFERENCES BECOME MAGNIFIED. THE 12Z GFS
MAINTAINS NORTHWESTERLY FLOW ALOFT...WITH THE MEAN RIDGE ACROSS THE
SOUTHWEST CONUS AND PERIODIC CHANCES FOR CONVECTION AS SHORTWAVE
DISTURBANCES DIVE SOUTHEASTWARD WITHIN THE STRONGER WESTERLIES. IN
CONTRAST...THE 12Z ECMWF SHOWS A STRONGER DISTURBANCE LIFTING ACROSS
THE PACIFIC NORTHWEST ON MONDAY INTO TUESDAY...WITH DOWNSTREAM
RIDGING MAINTAINING MORE ZONAL FLOW ACROSS THE NORTHERN PLAINS. WITH
THESE DIFFERENCES IN MIND...WILL MAINTAIN SOME POPS SUNDAY
NIGHT-TUESDAY...WITH SEASONABLE TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1144 PM CDT TUE JUL 16 2013
VFR CONDITIONS EXPECTED AT TAF SITES THRU THIS PD. SOME SC/AC WILL
BE AROUND ESP NORTH OF THE SFC BOUNDARY OVER NRN-CNTRL ND INTO FAR
NRN MN...BUT EXPECT THIS TO RANGE IN THE 5-10K FT RANGE. WINDS
WILL BE NORTH-NORTHEAST DVL-GFK-TVF TONIGHT TURNING A BIT MORE
EAST NR 10 KTS WED. FAR-BJI TO BE VERY NEAR THE BOUNDARY AND
LIKELY SEE MORE OF A VARIABLE WIND SITUATION...BRIEFLY NORTHEAST
OR EAST LATE TONIGHT-WED AM MAYBE TURNING BACK SOUTHEAST LATER
WED. SPEEDS 10 KTS OR LESS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...MAKOWSKI
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
142 PM EDT WED JUL 17 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BE THE DOMINATING WEATHER FEATURE
THROUGH FRIDAY. THE HIGH PRESSURE WAS CENTERED OVER OHIO AND WILL
GRADUALLY SLIDE SOUTHEAST INTO THE CAROLINAS BY FRIDAY. A COLD FRONT
WILL MOVE SOUTHEAST ACROSS THE AREA SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BOOSTED PARTS OF THE NW TO CHANCE POPS. SUBSTANTIAL CU FIELD IS
DEVELOPING INTO SCATTERED SHOWERS AND STORMS ACROSS SRN LWR MI AS
PRE THE HRRR MODEL FORECAST. BELIEVE THIS WILL EXTEND INTO PARTS
OF NWRN OHIO AS WELL. ALSO EXTENDED THE SLIGHT CHANCE FOR NERN
OHIO INTO CRAWFORD COUNTY PA AND THEN IN TIME INTO THE AFTERNOON.
PREVIOUS DISCUSSION...
THE HEAT IS ON. THE DOG DAYS OF SUMMER HAVE ARRIVED AS A
VERTICALLY STACKED DOME OF HIGH PRESSURE FROM 500 MB DOWN THE
SURFACE REMAINS IN PLACE TODAY. THE HIGH PRESSURE WILL CONTINUE TO
PUMP HIGH DEW POINT AIR INTO THE FORECAST AREA TODAY WITH DEW
POINTS REACHING THE MIDDLE 70S...ESPECIALLY NEAR LAKE ERIE AND
WESTERN THIRD OF THE FORECAST AREA. THE COMBINATION OF THE HIGH
DEW POINTS AND RESULTING HIGH HUMIDITY ALONG WITH HOT AIR
TEMPERATURES WILL CAUSE HEAT INDEX VALUES TO REACH BETWEEN 100 AND
104 THIS AFTERNOON INTO THE EVENING HOURS. SO...WE DECIDED TO
HOIST A HEAT ADVISORY FOR THE WESTERN THIRD OF THE FORECAST AREA
FOR TODAY. THE REST OF THE FORECAST AREA WILL STILL BE HOT AND
HUMID BUT WILL KEEP HEAT INDEXES DOWN TO BETWEEN 98 AND 99 DURING
THE AFTERNOON AND EVENING.
AS FAR AS THUNDERSTORMS GO...THE SUPPRESSION OF THE HIGH PRESSURE
OVERHEAD...DECIDED TO NOT MENTION THUNDERSTORMS ANY PLACE IN THE
FORECAST AREA. THERE COULD BE AN ISOLATED THUNDERSTORM THAT DEVELOPS
BUT AREAL COVERAGE SHOULD BE SO MINIMAL THAT IT IS NOT WORTH
MENTIONING AT THIS TIME.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE DOME OF HIGH PRESSURE IS EXPECTED TO MOVE SLOWLY SOUTHEAST
TONIGHT INTO FRIDAY. THIS WILL SHIFT THE SUPPRESSION FROM THE HIGH
TO THE SOUTH. HOWEVER...THE HEAT AND HUMIDITY WILL CONTINUE TONIGHT
MAKING IT FEEL VERY UNCOMFORTABLE FOR SLEEPING. THE HEAT CONTINUES
TOMORROW WITH A GOOD CHANCE THAT WE WILL NEED TO HOIST ANOTHER HEAT
ADVISORY FOR A MUCH LARGER AREA. HEAT INDEX VALUES ONCE AGAIN REACH
BETWEEN 100 AND 104 DURING THE AFTERNOON AND EVENING HOURS ON
THURSDAY. LITTLE CHANGE IF ANY IS EXPECTED THURSDAY NIGHT INTO
FRIDAY AS HOT MUGGY CONDITIONS CONTINUE.
A REPRIEVE ARRIVES ON SATURDAY AS A COLD FRONT SLIPS SOUTH ACROSS
THE AREA. THIS SHOULD KNOCK TEMPERATURES DOWN A FEW PEGS AND
DEFINITELY LOWER DEW POINT TEMPERATURES AS WELL. THIS SHOULD RESULT
IN NOTICEABLY COOLER TEMPERATURES AND HUMIDITY LEVELS.
AS THE FRONT MOVES THROUGH THE AREA...THE POTENTIAL EXISTS FOR THE
THREAT OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA.
THEREFORE...WILL HOLD ON TO THE LIKELY CATEGORY. MOISTURE ASSOCIATED
WITH THE COLD FRONT EXITS TO THE SOUTH FAIRLY QUICKLY AND WILL GO
AHEAD AND END THE THREAT FOR SHOWERS AND THUNDERSTORMS FROM NORTH TO
SOUTH IN THE AFTERNOON. FAIR WEATHER RETURNS AGAIN FOR SATURDAY
NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A COOLER AREA OF HIGH PRESSURE WILL BE BUILDING INTO THE REGION ON
SUNDAY IN THE WAKE OF A COLD FRONT THAT SHOULD BE NEAR THE EAST
COAST. AN UPPER LEVEL TROUGH WILL THEN TAKE UP RESIDENCE ACROSS THE
GREAT LAKES REGION FOR MONDAY INTO TUESDAY. THERE MAY BE A PIECE OF
JET ENERGY THAT MOVES THROUGH THIS TROUGH FROM LATE MONDAY INTO
TUESDAY. THIS WILL BRING INCREASING CHANCES OF THUNDERSTORMS. THE
STRONGER PIECE OF ENERGY WILL LIKELY NOT ARRIVE UNTIL WEDNESDAY.
TEMPERATURES SUNDAY INTO MONDAY MAY BE SLIGHTLY BELOW SEASONAL
AVERAGES BUT WE WILL WARM AHEAD OF THE NEXT COLD FRONT THAT WILL
ARRIVE WEDNESDAY INTO THURSDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CONTINUED VFR CONDITIONS. ISOLATED AFTERNOON SHRA/TS WOULD LIKELY
BE ISOLATED TO JUST THE TOLEDO AREA. OTHERWISE FOCUS IS SOUTHEAST
OF OUR SITES. MAY HAVE SOME PATCHY MVFR BR/HZ TOWARD THU MORNING
BUT NOT MUCH. VFR AGAIN THURSDAY WITH EVEN LESS OF A CHANCE FOR
SHRA/TS.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE WESTERN OHIO RIVER VALLEY WILL
GRADUALLY WEAKEN AS IT SHIFTS SOUTHEAST THROUGH FRIDAY. AS A COLD
FRONT APPROACHES ON FRIDAY IT APPEARS THAT SOUTHWESTERLY WINDS WILL
BE ON THE INCREASE. WINDS MAY INCREASE TO 15 TO 25 KNOTS ALLOWING
WAVES TO BUILD TO 3 TO 5 FEET FOR THE OPEN WATERS AND EASTERN HALF
OF THE LAKE. THESE STRONGER WINDS WILL PERSIST UNTIL A COLD FRONT
PASSES FRIDAY NIGHT INTO EARLY SATURDAY. SO WITH THAT SAID IT
APPEARS A SMALL CRAFT ADVISORY WILL BE NEEDED FRIDAY INTO AT LEAST
SATURDAY MORNING. HIGH PRESSURE WILL BUILD OVER THE LAKE SATURDAY
NIGHT INTO SUNDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR OHZ003-006>011-
013-017>023-027>033-036>038-047.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...TK/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...OUDEMAN
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1216 PM EDT WED JUL 17 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BE THE DOMINATING WEATHER FEATURE
THROUGH FRIDAY. THE HIGH PRESSURE WAS CENTERED OVER OHIO AND WILL
GRADUALLY SLIDE SOUTHEAST INTO THE CAROLINAS BY FRIDAY. A COLD FRONT
WILL MOVE SOUTHEAST ACROSS THE AREA SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BOOSTED PARTS OF THE NW TO CHANCE POPS. SUBSTANTIAL CU FIELD IS
DEVELOPING INTO SCATTERED SHOWERS AND STORMS ACROSS SRN LWR MI AS
PRE THE HRRR MODEL FORECAST. BELIEVE THIS WILL EXTEND INTO PARTS
OF NWRN OHIO AS WELL. ALSO EXTENDED THE SLIGHT CHANCE FOR NERN
OHIO INTO CRAWFORD COUNTY PA AND THEN IN TIME INTO THE AFTERNOON.
PREVIOUS DISCUSSION...
THE HEAT IS ON. THE DOG DAYS OF SUMMER HAVE ARRIVED AS A
VERTICALLY STACKED DOME OF HIGH PRESSURE FROM 500 MB DOWN THE
SURFACE REMAINS IN PLACE TODAY. THE HIGH PRESSURE WILL CONTINUE TO
PUMP HIGH DEW POINT AIR INTO THE FORECAST AREA TODAY WITH DEW
POINTS REACHING THE MIDDLE 70S...ESPECIALLY NEAR LAKE ERIE AND
WESTERN THIRD OF THE FORECAST AREA. THE COMBINATION OF THE HIGH
DEW POINTS AND RESULTING HIGH HUMIDITY ALONG WITH HOT AIR
TEMPERATURES WILL CAUSE HEAT INDEX VALUES TO REACH BETWEEN 100 AND
104 THIS AFTERNOON INTO THE EVENING HOURS. SO...WE DECIDED TO
HOIST A HEAT ADVISORY FOR THE WESTERN THIRD OF THE FORECAST AREA
FOR TODAY. THE REST OF THE FORECAST AREA WILL STILL BE HOT AND
HUMID BUT WILL KEEP HEAT INDEXES DOWN TO BETWEEN 98 AND 99 DURING
THE AFTERNOON AND EVENING.
AS FAR AS THUNDERSTORMS GO...THE SUPPRESSION OF THE HIGH PRESSURE
OVERHEAD...DECIDED TO NOT MENTION THUNDERSTORMS ANY PLACE IN THE
FORECAST AREA. THERE COULD BE AN ISOLATED THUNDERSTORM THAT DEVELOPS
BUT AREAL COVERAGE SHOULD BE SO MINIMAL THAT IT IS NOT WORTH
MENTIONING AT THIS TIME.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE DOME OF HIGH PRESSURE IS EXPECTED TO MOVE SLOWLY SOUTHEAST
TONIGHT INTO FRIDAY. THIS WILL SHIFT THE SUPPRESSION FROM THE HIGH
TO THE SOUTH. HOWEVER...THE HEAT AND HUMIDITY WILL CONTINUE TONIGHT
MAKING IT FEEL VERY UNCOMFORTABLE FOR SLEEPING. THE HEAT CONTINUES
TOMORROW WITH A GOOD CHANCE THAT WE WILL NEED TO HOIST ANOTHER HEAT
ADVISORY FOR A MUCH LARGER AREA. HEAT INDEX VALUES ONCE AGAIN REACH
BETWEEN 100 AND 104 DURING THE AFTERNOON AND EVENING HOURS ON
THURSDAY. LITTLE CHANGE IF ANY IS EXPECTED THURSDAY NIGHT INTO
FRIDAY AS HOT MUGGY CONDITIONS CONTINUE.
A REPRIEVE ARRIVES ON SATURDAY AS A COLD FRONT SLIPS SOUTH ACROSS
THE AREA. THIS SHOULD KNOCK TEMPERATURES DOWN A FEW PEGS AND
DEFINITELY LOWER DEW POINT TEMPERATURES AS WELL. THIS SHOULD RESULT
IN NOTICEABLY COOLER TEMPERATURES AND HUMIDITY LEVELS.
AS THE FRONT MOVES THROUGH THE AREA...THE POTENTIAL EXISTS FOR THE
THREAT OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA.
THEREFORE...WILL HOLD ON TO THE LIKELY CATEGORY. MOISTURE ASSOCIATED
WITH THE COLD FRONT EXITS TO THE SOUTH FAIRLY QUICKLY AND WILL GO
AHEAD AND END THE THREAT FOR SHOWERS AND THUNDERSTORMS FROM NORTH TO
SOUTH IN THE AFTERNOON. FAIR WEATHER RETURNS AGAIN FOR SATURDAY
NIGHT.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A COOLER AREA OF HIGH PRESSURE WILL BE BUILDING INTO THE REGION ON
SUNDAY IN THE WAKE OF A COLD FRONT THAT SHOULD BE NEAR THE EAST
COAST. AN UPPER LEVEL TROUGH WILL THEN TAKE UP RESIDENCE ACROSS THE
GREAT LAKES REGION FOR MONDAY INTO TUESDAY. THERE MAY BE A PIECE OF
JET ENERGY THAT MOVES THROUGH THIS TROUGH FROM LATE MONDAY INTO
TUESDAY. THIS WILL BRING INCREASING CHANCES OF THUNDERSTORMS. THE
STRONGER PIECE OF ENERGY WILL LIKELY NOT ARRIVE UNTIL WEDNESDAY.
TEMPERATURES SUNDAY INTO MONDAY MAY BE SLIGHTLY BELOW SEASONAL
AVERAGES BUT WE WILL WARM AHEAD OF THE NEXT COLD FRONT THAT WILL
ARRIVE WEDNESDAY INTO THURSDAY.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
PATCHY MVFR FOG WILL OCCUR THROUGH 13Z...MAINLY WHERE IT RAINED
YESTERDAY AFTERNOON. OTHERWISE EXPECT TO SEE VFR CONDITIONS
THROUGH THE DAY. THERE ARE A FEW SHOWERS OVER NE OHIO MOVING
TOWARD KYNG SO WE HAVE PLACED A VICINITY SHOWER IN THE TAF THROUGH
15Z.
OTHERWISE THERE IS A DECENT CAP ACROSS THE AREA TODAY. HOWEVER A
COUPLE OF THE MODELS ARE INDICATING SOME WEAK CONVERGENCE ACROSS
THE WESTERN COUNTY WARNING AREA. SO WE CANT COMPLETELY RULE OUT AN
ISOLATED STORM OR TWO NEAR KFDY BUT CHANCES OF THIS OCCURRING ARE
WAY TOO LOW TO MENTION IN THE TAF.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER THE WESTERN OHIO RIVER VALLEY WILL
GRADUALLY WEAKEN AS IT SHIFTS SOUTHEAST THROUGH FRIDAY. AS A COLD
FRONT APPROACHES ON FRIDAY IT APPEARS THAT SOUTHWESTERLY WINDS WILL
BE ON THE INCREASE. WINDS MAY INCREASE TO 15 TO 25 KNOTS ALLOWING
WAVES TO BUILD TO 3 TO 5 FEET FOR THE OPEN WATERS AND EASTERN HALF
OF THE LAKE. THESE STRONGER WINDS WILL PERSIST UNTIL A COLD FRONT
PASSES FRIDAY NIGHT INTO EARLY SATURDAY. SO WITH THAT SAID IT
APPEARS A SMALL CRAFT ADVISORY WILL BE NEEDED FRIDAY INTO AT LEAST
SATURDAY MORNING. HIGH PRESSURE WILL BUILD OVER THE LAKE SATURDAY
NIGHT INTO SUNDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR OHZ003-006>011-
013-017>023-027>033-036>038-047.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...TK/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS PORTLAND OR
859 PM PDT TUE JUL 16 2013
.SYNOPSIS...AN UPPER LEVEL LOW OFF THE CALIFORNIA COAST WILL MOVE
NORTHEAST OVER WESTERN OREGON AND SOUTHWEST WASHINGTON TONIGHT AND
POSSIBLY TRIGGER ELEVATED THUNDERSTORMS ACROSS THE REGION. COOLER
MARINE AIR WILL FILL IN ALONG THE COAST THIS EVENING SPREADING INLAND
OVERNIGHT. THIS WILL RESULT IN SIGNIFICANT COOLING WEDNESDAY. HIGH
PRESSURE WILL REBUILD THURSDAY AND TEMPERATURES WILL REBOUND THURSDAY
AND FRIDAY.
&&
.SHORT TERM...VISIBLE SATELLITE IMAGERY AND AREA WEBCAM LOOPS BOTH
SHOWED TODAYS CLOUD STORM QUITE WELL. ASIDE FROM SOME SPRINKLES AND
A COUPLE VERY ISOLATED RAIN SHOWERS THAT BROUGHT MEASURABLE
RAIN...MOST PRECIPITATION EVAPORATED BEFORE REACHING THE GROUND.
EARLIER THIS AFTERNOON...A FEW PUNY STORMS LAID DOWN A HANDFUL OF
LIGHTNING STRIKES ACROSS THE SOUTH WASHINGTON CASCADES...AND FOR
SEVERAL HOURS...LITTLE ACTIVITY FOLLOWED. HOWEVER...AN ISOLATED CELL
POPPED NEAR LINCOLN CITY THIS EVENING WITH ADDITIONAL CONVECTION
DEVELOPING OFFSHORE AROUND 7-8PM...LAYING DOWN ANOTHER HANDFUL OF
STRIKES OFF TILLAMOOK. THIS CONVECTION HAS EXPANDED NORTHWARD WITH
CELLS DEVELOPING NEAR ASTORIA THIS EVENING...BUT IT APPEARS ALL THE
LIGHTNING ASSOCIATED WITH THIS BAND OF CONVECTION WILL LIKELY STAY
OFFSHORE. AS PURELY AN ASIDE...IT PROBABLY WOULD HAVE MADE FOR SOME
INTERESTING PHOTOGRAPHY FOR ANYONE ON ONE OF THE HIGHER PEAKS OF THE
COAST RANGE...AS THEY LOOKED WEST OVER THE MARINE LAYER WITH A
THUNDERSTORM BACK LIT BY THE SETTING SUN.
ANYWAY...THE HRRR HAS VARIED WIDELY WITH ITS DEPICTION OF CONVECTION
ACROSS THE REGION TONIGHT...AND AS A RESULT...CONFIDENCE REMAINS LOW
IN ANY PARTICULAR SCENARIO IT PRODUCES...AT LEAST FOR NOW.
AS FOR THUNDER CHANCES TONIGHT...IT STILL SEEMS LIKE A LOW
PROBABILITY THREAT...BUT IT EXISTS NONETHELESS. THIS IS PRIMARILY DUE
TO THE UPPER LEVEL LOW PRESSURE CURRENTLY NEAR CAPE MENDOCINO AND THE
FACT THAT ITS HEADED STRAIGHT INTO WESTERN OREGON...MAINLY TOWARDS
THE WILLAMETTE VALLEY AND CASCADES. IN ADDITION...INCREASING UPPER
LEVEL LIFT AHEAD OF THIS FEATURE DUE TO MID LEVEL VORTICITY
ADVECTION...AND THE REGION BEING IN THE LEFT EXIT REGION OF A
70-80KT JET...COMBINED WITH A SWATH OF NEGATIVE 700-500MB THETAE
LAPSE RATES...AND STEEPENING MID LEVEL LAPSE RATES PER SPC ANALYSIS
MOVING OVERHEAD ALL SEEM FAVORABLE FOR NOCTURNAL CONVECTION TO
DEVELOP...PRIMARILY BETWEEN 06Z-15Z. THE THREAT APPEARS HIGHEST
NORTH AND EAST OF THE PORTLAND METRO AREA.
HOWEVER...A COUPLE MAJOR WRENCHES IN THE DEVELOPMENT OF CONVECTION
EXIST. FIRST...THE MAIN 700-500MB THETAE RIDGE IS NOW WELL NORTH OF
THE CWA...AND DRIER AIR ALOFT CONTINUES TO FEED INTO THE REGION.
MODEL SOUNDINGS ALSO SHOW ANY ADDITIONAL MOISTURE FEEDING INTO THE
REGION OVERNIGHT COMING IN AWFULLY CLOSE TO -10C WITH POSSIBLE
EQUILIBRIUM LEVELS NEAR -30C...NEITHER OF WHICH ARE TERRIBLY
FAVORABLE TO ACTUALLY PRODUCE THUNDER. CONFIDENCE IN THESE DETAILS
REMAINS LOW SO GIVEN THE SYNOPTIC PATTERN APPEARS AT LEAST
MODERATELY FAVORABLE...WILL OPT TO KEEP THE MENTION OF THUNDER GOING
THROUGH THE NIGHT TIME HOURS EVEN THOUGH CONFIDENCE IS STILL RATHER
LOW.
I DID TRIM THE MENTION OF THUNDER AS THE NIGHT WEARS ON FROM SOUTH TO
NORTH WITH THE USE OF 3 HR WX GRIDS. BY THURSDAY MORNING...TSTORM
CHANCES WILL LIKELY BE EAST OF OUR CWA...BUT I DID KEEP A MENTION
GOING ACROSS THE SOUTH WASHINGTON CASCADES WHERE UPPER LEVEL SUPPORT
COULD CAUSE STORMS TO LINGER INTO THE MORNING HOURS IF THEY IN FACT
DEVELOP.
MEANWHILE...A SIGNIFICANT SOUTHWEST MARINE PUSH IS UNDERWAY ACROSS
THE AREA THIS EVENING. MARINE CLOUDS ARE ON THE DOORSTEP OF CORVALLIS
AND EUGENE...BOTH OF WHICH HAVE BEEN QUITE GUSTY THIS EVENING...AND
HAVE COOLED DRAMATICALLY. THE INITIAL SURGE OF MARINE AIR COULD EVEN
BE SEEN ON THE KRTX RADAR ACROSS THE NORTHERN WILLAMETTE VALLEY THIS
EVENING AS A DISTINCT BOUNDARY MOVED NORTHWARD FROM SALEM/AURORA
INTO THE PORTLAND METRO AREA...CAUSING WINDS TO SHIFT TO A MORE
SOUTHERLY DIRECTION BETWEEN 00-02Z. GIVEN THE CURRENT EXTENT OF MARINE
CLOUDS AND LAYOUT OF THE PRESSURE GRADIENT...I INCREASED SKY COVER
ACROSS THE WILLAMETTE VALLEY FOR WEDNESDAY MORNING. THE INTRUSION OF
COOLER MARINE AIR SHOULD KEEP HIGH TEMPERATURES IN THE LOWER 80S FOR
INTERIOR LOCATIONS WEDNESDAY.
OTHERWISE...THE REST OF THE FORECAST APPEARS ON TRACK AND FEW CHANGES
WERE MADE. EXPECT HIGHS IN THE UPPER 80S AND SUNSHINE FOR INTERIOR
LOCATIONS WITH PERIODS OF CLOUDS AND COOLER TEMPERATURES ALONG THE
COAST FOR THURSDAY AND FRIDAY. /NEUMAN
.LONG TERM...HIGH PRESSURE WILL HOLD OVER THE AREA FRIDAY AND
CONTINUE ABOVE NORMAL TEMPERATURES ACROSS THE INTERIOR. MODELS
DIVERGE ON SOLUTIONS FOR SATURDAY AND BEYOND. THE GFS FORECASTS AN
UPPER LEVEL TROUGH TO MOVE NORTH OF THE AREA AND FLATTEN THE RIDGE
OVER THE WEEKEND...WHEREAS THE ECMWF FORECASTS AN UPPER LEVEL TROUGH
WILL MOVE DIRECTLY OVER NW OREGON SUNDAY AND MONDAY. MADE NO MAJOR
CHANGES TO THE LONG TERM AND CONTINUED WITH THE PREVIOUS THINKING
THAT THE TROUGH WILL RIDE OVER THE TOP OF THE RIDGE. WOULD LIKE TO
SEE GREATER MODEL CONSENSUS AND CONSISTENCY BEFORE JUMPING ON BOARD
WITH THE ECMWF. TH
&&
.AVIATION...IFR CONDITIONS WILL CONTINUE TO MOVE UP THE COAST
TONIGHT. IFR CIGS AT THE COAST WILL CONTINUE OVERNIGHT THEN
LIKELY LIFT TO MVFR ON WEDNESDAY. VISIBILITY AT THE COAST MAY
RISE TO MVFR LATE TONIGHT AND LIKELY TO VFR BY WEDNESDAY
AFTERNOON. EXPECT A SOUTHWEST MARINE PUSH TONIGHT TO BRING MVFR
CIGS INLAND FROM SOUTH TO NORTH AFTER MIDNIGHT...BREAKING UP AND
LIFTING TO VFR BY EARLY WEDNESDAY AFTERNOON. PT/BURGESS
KPDX AND APPROACHES...VFR THROUGH 12Z. A SLIGHT CHANCE OF THUNDER
REMAINS OVERNIGHT...WITH THE BEST CHANCE FROM 05Z- 12Z. A SURGE OF
MARINE MOISTURE IS EXPECTED TO BRING MVFR CLOUDS OVER THE AIRPORT
AFTER 12Z. PT/BURGESS
&&
.MARINE...NO CHANGES. SOUTHERLY WIND OVER THE INNER WATERS WILL
PERSIST THROUGH WEDNESDAY MORNING. EXPECT OCCASIONAL GUSTS TO 20
KT OVER THE NORTHERN INNER WATERS THROUGH WEDNESDAY MORNING.
NORTHERLY WINDS IN THE OUTER WATERS WILL CONTINUE TO TURN WEST OR
SOUTHWEST TONIGHT. THESE WINDS WILL CONTINUE INTO WEDNESDAY
MORNING THEN SHIFT MORE NORTHWESTERLY LATE WEDNESDAY AND
WEDNESDAY NIGHT. EXPECT SMALL CRAFT NORTHERLIES TO RECUR THURSDAY
AND FRIDAY.
EXPECT SEAS TO CONTINUE TO DIMINISH TONIGHT AND WEDNESDAY. PERIODS
WILL CONTINUE TO RUN AROUND 8 SECONDS SO SEAS WILL BE ON THE
CHOPPY SIDE. THERE IS SOME BACKGROUND SOUTHERLY SWELL BUT ONLY
AROUND 1 FOOT OR SO...SO WILL EMPHASIZE THE FRESH NORTHWESTERLY
SWELL. AT THIS POINT SEAS LOOK TO STAY BELOW 10 FT THROUGH THE
FORECAST PERIOD. PT/BURGESS
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1033 PM EDT THU JUL 18 2013
.SYNOPSIS...
A HUGE SUBTROPICAL RIDGE COVERS MOST OF THE UNITED STATES ALL THE
WAY TO THE CANADIAN BORDER. THIS DOMINANT WEATHER FEATURE WILL
CONTINUE TO PROVIDE MID-SUMMER HEAT AND HUMIDITY TO THE ENTIRE
REGION. THIS PATTERN WILL PERSIST THROUGH FRIDAY BEFORE A COLD FRONT
CROSSES THE REGION SATURDAY...FOLLOWED BY SOME SLIGHTLY COOLER
AND DRIER AIR FOR THE LAST HALF OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
REGIONAL RADAR MOSAIC SHOWS DIURNALLY-DRIVEN CONVECTION HAS
DISSIPATED AS OF 02Z. 02Z SPC MESOANALYSIS AND RAP DATA BOTH SHOW
FAIRLY HIGH CAPES REMAINING ACROSS THE SOUTHERN HALF OF THE STATE.
CAN/T COMPLETELY RULE OUT ANOTHER SHOWER ACROSS THIS AREA
OVERNIGHT. HOWEVER...GIVEN LACK OF LG SCALE FORCING AND COOLING
BLYR...WILL REMOVE MENTION OF RAIN FOR THE REST OF THE NIGHT.
A LIGHT WIND AND CLEARING SKY WILL LIKELY RESULT IN PATCHY FOG
LATER TONIGHT...MAINLY ACROSS THE N MTNS WHERE THERE WAS
WIDESPREAD RAINFALL EARLIER TODAY. AS AIR MASS REMAINS UNCHANGED...HAVE
STUCK CLOSE TO LAST NIGHT/S LOWS FOR TONIGHT...RANGING FROM THE
U60S ACROSS THE N MTNS...TO THE M70S ACROSS THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
HAVE PUT UP ANOTHER HEAT ADVISORY FOR THE EASTERN HALF OF MY FCST
AREA FRIDAY AFTERNOON AND EVENING AS THE HEATWAVE ROLLS ON. AFTER
A WARM START TO THE DAY...WE SHOULD ONCE AGAIN HAVE LITTLE PROBLEM
REACHING AFTERNOON HIGHS AT LEAST AS HOT AS TODAY WITH NO BREAK IN
THE HUMIDITY. 18Z GEFS MEAN 925MB TEMPS WARM BY ARND 1C FRIDAY VS
TODAY.
CONVECTIVE FORECAST A LITTLE DIFFERENT FOR FRIDAY...AS ANOMALOUS
UPPER RIDGE RETREATS SOUTHWARD AND STRONGER FLOW ALOFT WORKS INTO
PA. THUS...EXPECT BETTER ORGANIZATION/LONGEVITY TO SCT PM
CONVECTION...ESP NORTHWEST. STRONGEST WINDS ALOFT WILL BE ACROSS NW
PA...WHERE SPC HAS OUTLOOKED A SLIGHT RISK OF SVR. HOWEVER...THE
THREAT UP THERE MAY NOT ARRIVE UNTIL EVENING...AS LATEST GEFS SHOW
A PRONOUNCED AREA OF LOWER PWATS/CAPES ACROSS NW PA FRI AFTN.
SREF/GEFS BOTH INDICATE PLENTY OF CAPE ACROSS THE SOUTHEAST
COUNTIES FRI AFTN...WHERE POP UP STORMS EXPECTED WITH DAY TIME
HEATING. SOME OF THE MORE ROBUST UPDRAFTS COULD DROP DOWN SOME
STRONG WIND AND HEAVY RAIN...BUT OVERALL ACTIVITY SHOULD REMAIN
PRETTY SCATTERED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
NOT MUCH CHANGE FROM RECENT DAYS.
SOME CHC OF STORMS PRIOR TO 00Z SAT...BUT EXPECT MUCH OF THE
PERIOD BEFORE SAT TO BE DRY AND HOT.
AS NOTED YESTERDAY...FRONT MAY MOVE INTO NW PA A TAD FASTER...
BUT WITH FLOW MORE ZONAL...FRONT WILL WEAKEN AND SLOW ACROSS
S PA BY SUNDAY. THUS LEFT CHC IN FOR SUNDAY.
LEFT MONDAY AND TUE DRY. HUMIDITY WILL BE CLOSE BY. WENT
WITH 20 POPS FOR WED AND THU...AS DEWPOINTS EDGE UP...AND
MODELS HINT AT A WEAK UPPER LVL SYSTEMS LIFTING NE IN THE
GENERAL FLOW.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
SHOWERS AND THUNDERSTORMS ARE QUICKLY DIMINISHING IN COVERAGE. AT
THIS POINT MOST TERMINALS SITES WILL REMAIN FAIR AND DRY THROUGH THE
REMAINDER OF THE EVENING...SAVE FOR POSSIBLY UNV...WITH ANOTHER
BAND OF SHOWERS DEVELOPING OFF TO THE NW.
BY 4 OR 5Z...MORE THIN FOG AND HAZE CAN BE EXPECTED TO DROP VIZ DOWN
INTO THE 2-4 MILE RANGE OVER MOST OF THE AREA TONIGHT...BEFORE WE
SEE THE SCENARIO REPEAT ALL OVER AGAIN TOMORROW AS IT BURNS OFF
DURING THE MORNING. ISOLATED SHRA/TSRA WILL ALSO AGAIN DEVELOP
AGAIN TOMORROW AFTN.
OUTLOOK...
SAT...VFR WITH AREAS OF MVFR. SCT SHRA/TSRA. SOME TSRA COULD BE
STRONG. LOCAL RESTRICTIONS.
SUN...MVFR TO VFR. FEW SHOWERS...PERHAPS A THUNDERSTORM...MAINLY
EARLY AND ACROSS THE SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TO 8 PM EDT FRIDAY FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
931 PM EDT THU JUL 18 2013
.SYNOPSIS...
A HUGE SUBTROPICAL RIDGE COVERS MOST OF THE UNITED STATES ALL THE
WAY TO THE CANADIAN BORDER. THIS DOMINANT WEATHER FEATURE WILL
CONTINUE TO PROVIDE MID-SUMMER HEAT AND HUMIDITY TO THE ENTIRE
REGION. THIS PATTERN WILL PERSIST THROUGH FRIDAY BEFORE A COLD FRONT
CROSSES THE REGION SATURDAY...FOLLOWED BY SOME SLIGHTLY COOLER
AND DRIER AIR FOR THE LAST HALF OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
REGIONAL RADAR MOSAIC SHOWS DIURNALLY-DRIVEN CONVECTION HAS
RAPIDLY DISSIPATED AFTER SUNSET. 01Z SPC MESOANALYSIS AND RAP DATA
BOTH SHOW A BAND OF LINGERING HIGHER CAPES ACROSS THE CENTRAL
COUNTIES...RUNNING ROUGHLY FROM CLEARFIELD TO SCHUYLKILL. WILL
MAINTAIN A SLIGHT CHC OF A SHOWER IN THIS ZONE BTWN 01Z-03Z. AFTER
MIDNIGHT...THE HIGHEST PWATS/MOST UNSTABLE AIR MASS SHIFTS TO THE
S TIER COUNTIES. HOWEVER...GIVEN LACK OF LG SCALE FORCING AND
COOLING BLYR WILL KEEP THE FCST DRY AFTER MIDNIGHT.
A LIGHT WIND AND CLEARING SKY WILL LIKELY RESULT IN PATCHY FOG
LATER TONIGHT...MAINLY WHERE IT RAINED TODAY ACROSS THE N MTNS.
AS AIR MASS REMAINS UNCHANGED...HAVE BASICALLY USED LAST NIGHT/S
LOWS TO TONIGHT...RANGING FROM THE U60S IN THE COOL SPOTS OF THE
ALLEGHENIES...TO THE M70S ACROSS THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
HAVE PUT UP ANOTHER HEAT ADVISORY FOR THE EASTERN HALF OF MY FCST
AREA FRIDAY AFTERNOON AND EVENING AS THE HEATWAVE ROLLS ON. AFTER
A WARM START TO THE DAY...WE SHOULD ONCE AGAIN HAVE LITTLE PROBLEM
REACHING AFTERNOON HIGHS AT LEAST AS HOT AS TODAY WITH NO BREAK IN
THE HUMIDITY. 18Z GEFS MEAN 925MB TEMPS WARM BY ARND 1C FRIDAY VS
TODAY.
CONVECTIVE FORECAST A LITTLE DIFFERENT FOR FRIDAY...AS ANOMALOUS
UPPER RIDGE RETREATS SOUTHWARD AND STRONGER FLOW ALOFT WORKS INTO
PA. THUS...EXPECT BETTER ORGANIZATION/LONGEVITY TO SCT PM
CONVECTION...ESP NORTHWEST. STRONGEST WINDS ALOFT WILL BE ACROSS NW
PA...WHERE SPC HAS OUTLOOKED A SLIGHT RISK OF SVR. HOWEVER...THE
THREAT UP THERE MAY NOT ARRIVE UNTIL EVENING...AS LATEST GEFS SHOW
A PRONOUNCED AREA OF LOWER PWATS/CAPES ACROSS NW PA FRI AFTN.
SREF/GEFS BOTH INDICATE PLENTY OF CAPE ACROSS THE SOUTHEAST
COUNTIES FRI AFTN...WHERE POP UP STORMS EXPECTED WITH DAY TIME
HEATING. SOME OF THE MORE ROBUST UPDRAFTS COULD DROP DOWN SOME
STRONG WIND AND HEAVY RAIN...BUT OVERALL ACTIVITY SHOULD REMAIN
PRETTY SCATTERED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
NOT MUCH CHANGE FROM RECENT DAYS.
SOME CHC OF STORMS PRIOR TO 00Z SAT...BUT EXPECT MUCH OF THE
PERIOD BEFORE SAT TO BE DRY AND HOT.
AS NOTED YESTERDAY...FRONT MAY MOVE INTO NW PA A TAD FASTER...
BUT WITH FLOW MORE ZONAL...FRONT WILL WEAKEN AND SLOW ACROSS
S PA BY SUNDAY. THUS LEFT CHC IN FOR SUNDAY.
LEFT MONDAY AND TUE DRY. HUMIDITY WILL BE CLOSE BY. WENT
WITH 20 POPS FOR WED AND THU...AS DEWPOINTS EDGE UP...AND
MODELS HINT AT A WEAK UPPER LVL SYSTEMS LIFTING NE IN THE
GENERAL FLOW.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
SHOWERS AND THUNDERSTORMS ARE QUICKLY DIMINISHING IN COVERAGE. AT
THIS POINT MOST TERMINALS SITES WILL REMAIN FAIR AND DRY THROUGH THE
REMAINDER OF THE EVENING...SAVE FOR POSSIBLY UNV...WITH ANOTHER
BAND OF SHOWERS DEVELOPING OFF TO THE NW.
BY 4 OR 5Z...MORE THIN FOG AND HAZE CAN BE EXPECTED TO DROP VIZ DOWN
INTO THE 2-4 MILE RANGE OVER MOST OF THE AREA TONIGHT...BEFORE WE
SEE THE SCENARIO REPEAT ALL OVER AGAIN TOMORROW AS IT BURNS OFF
DURING THE MORNING. ISOLATED SHRA/TSRA WILL ALSO AGAIN DEVELOP
AGAIN TOMORROW AFTN.
OUTLOOK...
SAT...VFR WITH AREAS OF MVFR. SCT SHRA/TSRA. SOME TSRA COULD BE
STRONG. LOCAL RESTRICTIONS.
SUN...MVFR TO VFR. FEW SHOWERS...PERHAPS A THUNDERSTORM...MAINLY
EARLY AND ACROSS THE SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TO 8 PM EDT FRIDAY FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE/GARTNER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
824 PM MDT THU JUL 18 2013
.UPDATE...
ISSUED AT 821 PM MDT THU JUL 18 2013
02Z SURFACE ANALYSIS SHOWED COOL FRONT/TROUGH EXITING CWA. DIURNAL
CYCLE TAKING IT/S TOLL ON TSRA WITH ACTIVITY ABOUT DONE SAVE FOR
SOME ANVIL DEBRIS. LOOKS PRETTY QUITE OVERNIGHT PER 00Z RAP AND
00Z KUNR SOUNDING. WILL LEAVE SMALL POPS NEAR THE NE BORDER GIVEN
NUMEROUS BOUNDARIES AND PROXIMITY TO 850-700MB FRONT AND ELEVATED
INSTABILITY.
&&
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 221 PM MDT THU JUL 18 2013
NORTHERN STREAM IMPULSE CONTINUES TO ADVECT/PROPAGATE
TO THE EAST ACROSS SOUTHERN SK/MB WITH AN ORPHANING TROUGH AXIS OVER
THE SOUTHERN FA. MOISTURE POOLING JUST BEHIND THE TROUGH COUPLED
WITH DIURNAL HEATING/SOUTHERN BH CONVERGENCE/AND WEAK LSA HAS
SUPPORTED A CLUSTER OF THUNDERSTORMS OVER THE SOUTHERN BH...WITH
ADDITIONAL CELLS EXPECTED TO INITIATE ACROSS THE EASTERN AND
SOUTHERN FA THIS AFTERNOON AND EVENING...AS THE TROUGH PROGRESSES SE
AND INHIBITION WEAKENS PER DIURNAL HEATING. CELLS WILL CONTINUE TO
FIGHT THE CAPPING INVERSION ACROSS THE EASTERN AND SE FA WITH FAIRLY
WARM TEMPS ALOFT HIGHLY LIMITING CAPE. MARGINAL TO WEAK DEEP LAYER
SHEAR SHOULD PREVENT MOST STORMS FROM ORGANIZATION...REMAINING PULSE
DRIVEN. WIDESPREAD MASSIVE CONUS RIDGE WILL EVENTUALLY FLATTEN AS A
STRONGER MORE PRONOUNCED UPPER SHORTWAVE DIGS SE INTO THE GREAT
LAKES THROUGH FRIDAY. MEANWHILE...LOCAL DEEP LAYER FLOW WILL TURN
NW...WITH IMPULSES ORIGINATING FROM THE CLOSED NE PAC UPPER LOW
EXPECTED IN THE FLOW. AFOREMENTIONED TROUGH AND ASSOCIATED LL
MOISTURE BUBBLE WITH THETA-E POOLING WILL RESIDE OVERT THE SW FA
THROUGH FRIDAY NIGHT. FORECAST MODELS ARE IN RATHER STRONG AGREEMENT
THAT A WEAK...BUT SUFFICIENT IMPULSE WILL PASS THROUGH THE FLOW FRI
NIGHT...WITH REFLECTED FRONT SIDE SOUTHERLY FLOW /INDICATED WELL AT
H7/ EXPECTED TO SUPPORT A PERIOD OF POS THETA-E ADV UNDER FAIRLY
STEEP MID LEVEL LAPSE RATES. GIVEN AMPLE LL SLIGHTLY ELEVATED
MOISTURE IN PLACE...SHOWER AND THUNDERSTORMS CHANCES LOOK GOOD OVER
THE REGION...WITH THE POSSIBLY OF A SMALL MCS. THERE IS A SMALL
POTENTIAL FOR A SEVERE STORM OR TWO FRI NIGHT. PROGGED DEEP LAYER
SHEAR UTILIZING AN ELEVATED PARCEL SUGGEST 30 TO 45 KNOTS OF BULK
SHEAR...WITH MU CAPE AOA 1000 J/KG ACROSS THE FAR SW FA PER NAM
DATA. THIS WILL HAVE TO WATCHED.
RETAINED LOW CHANCE POPS ACROSS THE SE FA THROUGH THIS
EVENING...WITH LOW SLIGHTS ACROSS THE FAR SW LATE TONIGHT FOR
POSSIBLE ELEVATED SHOWERS...WHICH MAY END UP AS JUST VIRGA. ALSO
RETAINED LOW SLIGHTS ACROSS THE SW FA FRI GIVEN THE COLLOCATION OF
THE LL THETA-E PLUME. HOWEVER...MODEL DATA SUGGEST THAT THIS PLUME
OF MOISTURE WILL REMAIN ELEVATED. HENCE...ANY MODEL GENERATED QPF IN
THIS PERIOD MAY BE FROM AN ACCAS PLUME. DID TREND POPS UP ACROSS THE
SW HALF FRIDAY NIGHT GIVEN ABOVE CONCERNS.
AS FOR TEMPS...WARM TO HOT CONDITIONS CAN BE EXPECTED MOST PLACES
FRIDAY...ALTHOUGH 5 TO 10 DEGREES COOLER THAN TODAY/S TEMPS AS THE
THERMAL RIDGE SHIFTS EAST. LOWS GENERALLY IN THE 60S CAN BE
EXPECTED BOTH TONIGHT AND FRIDAY NIGHT.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 221 PM MDT THU JUL 18 2013
BROAD...RELATIVELY FLAT LONG WAVE RIDGE HAS
RETROGRESSED TO ABOUT 105W WITH NEXT UPSTREAM TROF NEAR 130W. RIDGE
IS FCST BY BOTH GFS AND ECMWF MODELS TO CONTINUE MOVING W WARD TO
NEAR THE PAC COAST BY 12Z SATURDAY AND TO NEAR 130W BY 12Z SUNDAY.
THE TREND IS THEN FOR IT TO MOVE SLOWLY E WARD AND AMPLIFY A BIT BY
12Z WED. THIS PLACES WEAK WNW FLOW OVER OUR CWA DURING ALL OF THE
LONG TERM PERIOD. SEVERAL WEAK SHORT WAVES WILL MOVE ACROSS THE AREA
IN THIS FLOW. TIMING OF THESE WAVES IS HANDLED VERY DIFFERENTLY BY
EACH OF THE MODELS...SO HAVE NOT TRIED TO PIN THEM DOWN TOO CLOSELY
IN POPS.
STAYED CLOSE TO GUIDANCE IN TEMPS WITH LITTLE REASON TO DEPART.
AS NOTED BY PREVIOUS SHIFT...EXTENDED GRID INITIALIZATION PLACED DEW
POINTS THE LOOK TOO HIGH OVER OUR WY COUNTIES. THE INITIALIZATION IS
NOT HANDLING DIURNAL DEW POINT TRENDS WELL...SO MOST NIGHT TIME DEW
POINTS WERE LOWERED CLOSER TO GFS AND EURO MOS.
&&
.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 516 PM MDT THU JUL 18 2013
ISOLATED TSRA ARE POSSIBLE TONIGHT NEAR THE NE BORDER. OTHERWISE...VFR
CONDITIONS ARE EXPECTED INTO FRIDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...BARBER
AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1115 PM MDT TUE JUL 16 2013
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 253 PM MDT TUE JUL 16 2013
AT 20Z A MODERATE AMOUNT OF CU DEVELOPMENT WAS TAKING
PLACE ALONG THE COOL FRONT BOUNDAY ACROSS EXTREME NORTHWESTERN SOUTH
DAKOTA THIS AFTERNOON. NO LIGHTNING YET, BUT THE HRRR 17Z UPDATE
SHOWED SOME MINIMAL RW- ACTIVITY BETWEEN 00Z AND 02Z JUST BARELY
ACROSS THE NORTHWEST CORNER OF THE STATE. THE SOUTHEASTERN EDGE OF
THE SOUTHEASTERN MONTANA LOW ST FIELD MENTIONED IN THE MORNING
UPDATE WAS DISSIPATING AND RETREATING NORTHWARD AS THE CYCLONIC
CIRCULATION AROUND THE WEAK SURFACE LOW BECAME MORE EASTERLY IN THIS
REGION.
ON A LARGER SCALE THE RIDGE EXTENDING WESTWARD INTO THE CENTRAL
PLAINS HAS PRETTY MUCH CUT OFF SIGNIFICANT MOIST RETURN FLOW TO THE
DAKOTAS THIS AFTERNOON IN THE MID AND UPPER LEVELS . DEWPOINTS ARE
DOWN 10 TO 12 DEGREES FROM YESTERDAY AFTERNOON AND MODEL SOUNDINGS
SHOW A VERY DRY STABLE AIR MASS.
FOR WEDNESDAY THE WEAK COOL FRONT IS FORECAST TO DRIFT SOUTHWARD
ACROSS NORTHWEST SOUTH DAKOTA. HOWEVER THE WESTERLYS AND ANY UPPER
LEVEL IMPULSES WILL REMAIN WELL NORTH OF THE FORECAST AREA AND
AIRMASS MOISTURE WILL CONTINUE TO BE MINIMAL. TEMPERATURES ARE
FORECAST TO BE A DEGREE OR SO WARMER THAN THIS AFTERNOON.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 253 PM MDT TUE JUL 16 2013
VERY BROAD...FLAT LONG WAVE RIDGE OVER THE GREAT LAKES WILL
RETROGRESS TO THE PACIFIC COAST BY 12Z FRIDAY AND INCREASE SOMEWHAT
IN AMPLITUDE. GFS AND ECMWF BOTH SHOW THIS TREND. RESULT IS THAT
WEAK NORTHWESTERLY FLOW DEVELOPS OVER OUR CWA ON THURSDAY AND
FRIDAY ALLOWING A COLD FRONT TO MOVE ACROSS THE AREA. THIS WILL DROP
TEMPERATURES A BIT AND RESULT IN CHANCES FOR SCATTERED TSTM
DEVELOPMENT. UNCERTAINTY IN THE EXACT LOCATION OF THE RIDGE...THE
STRENGTH OF THE NORTHWESTERLY FLOW EAST OF IT...AND THE POSITION AND
TIMING OF SHORT WAVES EMBEDDED IN THIS FLOW ALL LEAD TO SUBSTANTIAL
UNCERTAINTY IN THE FORECAST FOR THE WEEKEND AND BEYOND. STAYED CLOSE
TO GUIDANCE WITH TEMPS AND PROBS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1113 PM MDT TUE JUL 16 2013
AREA OF MVFR CIGS WILL PERSIST THROUGH THE NIGHT ACROSS PORTIONS
OF NORTHEAST WYOMING INTO NORTHWEST SOUTH DAKOTA. OTHERWISE VFR
CONDITIONS EXPECTED THROUGH WEDNESDAY EVENING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...CARPENTER
LONG TERM...BARBER
AVIATION...7
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
931 AM EDT WED JUL 17 2013
.DISCUSSION...
HIGH PRESSURE WILL REMAIN CENTERED OVER THE OHIO VALLEY
TODAY...PRODUCING A NE FLOW ALOFT OVER THE SOUTHERN APPALACHIANS.
WITH A LACK OF SYNOPTIC FORCING...CONVECTIVE DEVELOPMENT WILL FAVOR
THE HIGHER TERRAIN OF THE MOUNTAINS AND PLATEAU. LIKE
YESTERDAY...CONVECTION IS EXPECTED TO DEVELOP OVER WESTERN
NC...AND DRIFT W-SW. THE RUC AND NAM ARE IN AGREEMENT WITH THIS
SCENARIO. POPS WILL BE ADJUSTED UPWARD SLIGHTLY IN THE MOUNTAINS
AND PLATEAU...AND LOWERED SLIGHTLY IN THE VALLEY.
BASED ON THE 1000-850 THICKNESS VALUES FROM THE 12Z OHX
SOUNDING...WHICH ARE HIGHER TODAY THAN YESTERDAY...AND CURRENT OBS
WHICH ARE RUNNING A BIT ABOVE FORECAST...WILL RAISE HIGH TEMPS A
FEW DEGREES.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
858 PM CDT THU JUL 18 2013
.UPDATE...
SEE EVENING UPDATE.
&&
.DISCUSSION...
A VARIETY OF CONDITIONS ACROSS SE TX THIS EVENING. SFC DEW POINTS
VARY WILDLY ACROSS THE AREA WITH MID 50S OVER THE EXTREME NW
ZONES...MID TO UPPER 60S CENTRAL AND LOWER TO MID 70S ALONG THE
COAST AND OVER THE NORTHEAST. CONVECTION OVER THE CWA HAS WANED
AND THE STORMS TO THE EAST ALSO SHOWS SIGNS OF WEAKENING. THE
LATEST RAP SUPPORTS OTHER SHORT TERM MODELS WITH CONVECTION
GENERALLY ENDING WITH POSSIBLE REDEVELOPMENT ALONG THE COAST PRIOR
TO SUNRISE. 00Z SOUNDINGS SHOW PW VALUES NEAR 1.9 INCHES AND 1.7
INCHES AT CRP. 850 MB MOISTURE WAS HIGHER OVER LOUISIANA AND DRIER
TOWARD THE MIDDLE AND LOWER TEXAS COAST. A WEAK 850 MB LOW WAS
LOCATED OVER EASTERN LOUISIANA WITH A WEAKNESS ALOFT ALSO OVER
EASTERN LA. THIS WEAKNESS IS PROGGED TO SHIFT WEST ON FRIDAY AND
WILL PROBABLY BRING THE EASTERN HALF OF THE AREA SLIGHTLY HIGHER
RAIN CHANCES. WILL ISSUE NEW ZONES TO CLEAN UP EVENING WORDING
ONCE THE THREAT FOR CONVECTION ENDS. 43
&&
.PREV DISCUSSION... /ISSUED 647 PM CDT THU JUL 18 2013/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
40
AVIATION...
THE MAIN WEATHER FEATURES AFFECTING SE TX AT 2330Z THIS EVENING
WERE THE SURFACE HIGH PRESSURE RIDGE EXTENDING INTO THE AREA FROM
KY AND WHAT LOOKED TO BE A TUTT LOW INLAND OF THE FL AND AL
COASTS. THE DRY MID AND UPPER LEVEL AIRMASS THAT WAS OVER THE AREA
EARLIER TODAY WAS PUSHING OFF TO THE SOUTHWEST. ISOLATED SHOWERS
WILL LIKELY AFFECT AT LEAST KUTS AND KCLL THROUGH ABOUT 02Z OR SO.
THESE MAY DEVELOP A BIT FURTHER TO THE SOUTH AND WILL AMEND IF
NECESSARY. OTHER STORMS OVER WESTERN LA SHOULD DISSIPATE AFTER
SUNSET.
ALTHOUGH THERE MAY BE ANOTHER ISOLATED EPISODE OF A SITE
EXPERIENCING IFR OR LOWER LATE TONIGHT OR EARLY FRIDAY MORNING...
EXPECT MOST LOCATIONS TO REMAIN VFR THROUGH THE NIGHT AND ON
FRIDAY. WENT WITH MVFR FOR KUTS AND KCXO BUT THESE CONDITIONS
COULD ALSO AFFECT KLBX AS WELL. FOR THE MOST PART...FELT THAT AS
THE UPPER LOW MOVES WESTWARD THAT SE TX SHOULD BE IN THE
RELATIVELY DRIER SIDE OF THE SYSTEM THROUGH MIDDAY. THE EXCEPTIONS
SHOULD BE THOSE LOCATIONS NEAR AND ALONG THE COAST IF ISOLATED
SHOWERS DEVELOP OFF THE COAST AND MOVE INLAND DURING THE MORNING.
THE NAM12 WAS MORE AGGRESSIVE TOMORROW AFTERNOON AND FELT THAT
THE CHANCES WERE HIGH ENOUGH GIVEN THAT ANY MOISTURE WRAPPING
AROUND THE UPPER LOW SHOULD HELP ENHANCE THE SEABREEZE OR THE LIFT
PROVIDED BY THE UPPER LEVEL SYSTEM. FOR NOW WILL END THE RAIN
CHANCES NEAR THE COAST AND GO WITH A VCSH DURING THE LATTER HALF
OF THE AFTERNOON FOR MOST INLAND SITES NEAR THE METRO HOUSTON
AIRPORTS.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 93 72 94 73 / 20 20 20 30 10
HOUSTON (IAH) 75 93 73 93 73 / 20 30 20 30 20
GALVESTON (GLS) 79 90 79 89 78 / 20 30 20 30 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1155 AM CDT WED JUL 17 2013
.AVIATION...
A VERY MOIST SELY TROPICAL INFLOW FROM THE GULF INTO S TX WILL
PERSIST FOR THE NEXT 24 HOURS. THEREFORE VARIABLE CONDITIONS
PREVAILING WITH IFR-MVFR CIGS OFTEN GIVING WAY TO VFR CONDITIONS IN
THE AFTERNOON...WITH MVFR-IFR CONDITIONS GENERALLY PREVAILING IN
THE OVERNIGHT INTO THE MID MORNING HOURS. CIGS AND VSBYS WILL
QUICKLY LOWER TO MVFR-IFR IN THE SCT SHRA/ISOLD TSRA THRU THE
PERIOD. E-SELY WINDS PREVAILING AT 5-15 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 1122 AM CDT WED JUL 17 2013/
UPDATE...
POPS CURRENTLY APPEAR A BIT OVERDONE FOR SOUTH CENTRAL TEXAS BASED
ON LATE MORNING RADAR LOOPS...BUT CONVECTION BUILDING OVER THE
COASTAL BEND SUGGESTS MUCH MORE RAIN COVERAGE WILL DEVELOP THIS
AFTERNOON. FINER RESOLUTION MODELS SUCH AS THE HRRR CONTINUE TO
INDICATE A HIGH CHANCE OF RAIN IN THE AFTERNOON HOURS. THUS THE
MORNING PACKAGE FOR RAIN AND TEMPERATURES APPEARS ON TRACK.
PREV DISCUSSION... /ISSUED 635 AM CDT WED JUL 17 2013/
AVIATION...
SCT-NUMEROUS SHRA/ISOLD TSRA CAN BE EXPECTED TODAY INTO EVENING.
HAVE TEMPO GROUPS I-35 TAFS 14Z-21Z AND KDRT 19Z-23Z. SHRA/TSRA
DECREASE LATE EVENING INTO OVERNIGHT AS AIRMASS STABILIZES AND
THEN ISOLD-SCT SHRA/TSRA REDEVELOP THURSDAY. ALTHOUGH HAVE LEFT
MENTION OUT OF TAFS DUE UNCERTAINTY ON LOCATION...CAN NOT RULE
OUT SHRA/TSRA AT TAF SITES TONIGHT OR THURSDAY AS AIRMASS REMAINS
MOIST. LIFR/IFR CIGS EARLY THIS MORNING LIFT TO VFR THIS AFTERNOON
INTO EVENING...EXCEPT LOCAL MVFR CIGS IN/NEAR SHRA/TSRA.
REDEVELOPMENT OF IFR/MVFR CIGS EXPECTED OVERNIGHT INTO THURSDAY
MORNING. ELY WINDS 5 TO 12 KTS WILL PREVAIL. EXCEPT GUSTS TO 30
KTS IN AND NEAR SHRA/TSRA THIS AFTERNOON INTO EVENING.
PREV DISCUSSION... /ISSUED 409 AM CDT WED JUL 17 2013/
SHORT TERM (TODAY THROUGH THURSDAY)...
ANOTHER ROUND OF HEAVY SHOWERS AND ISOLATED THUNDERSTORMS IS
EXPECTED ALONG THE I-35 CORRIDOR LATE THIS MORNING INTO THE
AFTERNOON HOURS AND THEN OVER THE EDWARDS PLATEAU AND RIO GRANDE
PLAINS LATE THIS AFTERNOON AND EVENING. RAINFALL AMOUNTS WILL RANGE
FROM 1/4 TO 3/4 INCH WITH LOCALIZED 1 TO 2 INCHES.
AS THE UPPER LOW LEVEL SYSTEM OVER CENTRAL NEW MEXICO EARLY THIS
MORNING MOVES TO THE SOUTHWEST AND AWAY FROM SOUTH CENTRAL TEXAS...
ANOTHER LOW TO MID LEVEL DISTURBANCE ACROSS THE NORTHWEST PORTION
OF THE GULF OF MEXICO WILL MOVE NORTHWESTWARD AND OVER SOUTH TEXAS
THROUGHOUT THE DAY. WITH PRECIPITABLE WATER VALUES RANGING FROM 2
TO 2.15 INCHES ACROSS THE I-35 CORRIDOR AND OVER THE COASTAL
PLAINS PER GROUND-BASED SATELLITE READINGS AND MODERATE
INSTABILITY...EXPECT SHOWERS AND THUNDERSTORMS TO FORM ACROSS THE
COASTAL PLAINS AND MOVE INLAND FOR MUCH OF THE DAY. LATER THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS WILL BE MAINLY OVER THE
WESTERN HALF OF SOUTH CENTRAL TEXAS AS AN UPPER LEVEL RIDGE OF
HIGH PRESSURE BUILDS FROM THE NORTHEAST. THERE MAY BE SOME
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS LATER TONIGHT INTO
THE OVERNIGHT HOURS...BUT OVERALL...WEATHER CONDITIONS WILL BE
IMPROVING ON THURSDAY ACROSS MOST AREAS WITH THE EXCEPTION OF
SEA-BREEZE ENHANCED CONVECTION ACROSS THE COASTAL AND RIO GRANDE
PLAINS.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
UPPER LEVEL RIDGING WILL BE DOMINATING THE REGION LATER IN THE
WEEK INTO THE UPCOMING WEEKEND WITH ONLY SEA-BREEZE ENHANCED
ACTIVITY ACROSS THE SOUTHEASTERN COUNTIES OF SOUTH CENTRAL TEXAS
EACH AFTERNOON THROUGH SUNDAY. A WARMING TREND IS ON THE WAY FOR THE
NEXT SEVERAL DAYS THANKS TO THE UPPER RIDGE. MOSTLY DRY WEATHER
CONDITIONS ARE EXPECTED FROM MONDAY AND TUESDAY OF NEXT WEEK WITH
HIGHS IN THE UPPER 90S TO NEAR 100.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 88 74 95 74 98 / 60 30 20 10 10
AUSTIN BERGSTROM INTL AIRPORT 89 72 95 71 97 / 60 30 20 10 10
NEW BRAUNFELS MUNI AIRPORT 85 71 93 71 95 / 60 30 20 10 -
BURNET MUNI AIRPORT 81 72 91 73 92 / 60 30 20 10 10
DEL RIO INTL AIRPORT 87 74 89 75 92 / 70 50 40 20 10
GEORGETOWN MUNI AIRPORT 86 72 94 73 95 / 60 30 20 10 10
HONDO MUNI AIRPORT 88 73 93 73 95 / 70 40 30 10 -
SAN MARCOS MUNI AIRPORT 85 73 93 72 96 / 60 30 20 10 10
LA GRANGE - FAYETTE REGIONAL 90 74 98 74 96 / 60 30 20 10 20
SAN ANTONIO INTL AIRPORT 85 75 93 75 95 / 60 30 20 10 -
STINSON MUNI AIRPORT 85 73 93 74 95 / 70 30 30 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...01
SYNOPTIC/GRIDS...08
PUBLIC SERVICE/DATA COLLECTION...12
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1122 AM CDT WED JUL 17 2013
.UPDATE...
POPS CURRENTLY APPEAR A BIT OVERDONE FOR SOUTH CENTRAL TEXAS BASED
ON LATE MORNING RADAR LOOPS...BUT CONVECTION BUILDING OVER THE
COASTAL BEND SUGGESTS MUCH MORE RAIN COVERAGE WILL DEVELOP THIS
AFTERNOON. FINER RESOLUTION MODELS SUCH AS THE HRRR CONTINUE TO
INDICATE A HIGH CHANCE OF RAIN IN THE AFTERNOON HOURS. THUS THE
MORNING PACKAGE FOR RAIN AND TEMPERATURES APPEARS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 635 AM CDT WED JUL 17 2013/
AVIATION...
SCT-NUMEROUS SHRA/ISOLD TSRA CAN BE EXPECTED TODAY INTO EVENING.
HAVE TEMPO GROUPS I-35 TAFS 14Z-21Z AND KDRT 19Z-23Z. SHRA/TSRA
DECREASE LATE EVENING INTO OVERNIGHT AS AIRMASS STABILIZES AND
THEN ISOLD-SCT SHRA/TSRA REDEVELOP THURSDAY. ALTHOUGH HAVE LEFT
MENTION OUT OF TAFS DUE UNCERTAINTY ON LOCATION...CAN NOT RULE
OUT SHRA/TSRA AT TAF SITES TONIGHT OR THURSDAY AS AIRMASS REMAINS
MOIST. LIFR/IFR CIGS EARLY THIS MORNING LIFT TO VFR THIS AFTERNOON
INTO EVENING...EXCEPT LOCAL MVFR CIGS IN/NEAR SHRA/TSRA.
REDEVELOPMENT OF IFR/MVFR CIGS EXPECTED OVERNIGHT INTO THURSDAY
MORNING. ELY WINDS 5 TO 12 KTS WILL PREVAIL. EXCEPT GUSTS TO 30
KTS IN AND NEAR SHRA/TSRA THIS AFTERNOON INTO EVENING.
PREV DISCUSSION... /ISSUED 409 AM CDT WED JUL 17 2013/
SHORT TERM (TODAY THROUGH THURSDAY)...
ANOTHER ROUND OF HEAVY SHOWERS AND ISOLATED THUNDERSTORMS IS
EXPECTED ALONG THE I-35 CORRIDOR LATE THIS MORNING INTO THE
AFTERNOON HOURS AND THEN OVER THE EDWARDS PLATEAU AND RIO GRANDE
PLAINS LATE THIS AFTERNOON AND EVENING. RAINFALL AMOUNTS WILL RANGE
FROM 1/4 TO 3/4 INCH WITH LOCALIZED 1 TO 2 INCHES.
AS THE UPPER LOW LEVEL SYSTEM OVER CENTRAL NEW MEXICO EARLY THIS
MORNING MOVES TO THE SOUTHWEST AND AWAY FROM SOUTH CENTRAL TEXAS...
ANOTHER LOW TO MID LEVEL DISTURBANCE ACROSS THE NORTHWEST PORTION
OF THE GULF OF MEXICO WILL MOVE NORTHWESTWARD AND OVER SOUTH TEXAS
THROUGHOUT THE DAY. WITH PRECIPITABLE WATER VALUES RANGING FROM 2
TO 2.15 INCHES ACROSS THE I-35 CORRIDOR AND OVER THE COASTAL
PLAINS PER GROUND-BASED SATELLITE READINGS AND MODERATE
INSTABILITY...EXPECT SHOWERS AND THUNDERSTORMS TO FORM ACROSS THE
COASTAL PLAINS AND MOVE INLAND FOR MUCH OF THE DAY. LATER THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS WILL BE MAINLY OVER THE
WESTERN HALF OF SOUTH CENTRAL TEXAS AS AN UPPER LEVEL RIDGE OF
HIGH PRESSURE BUILDS FROM THE NORTHEAST. THERE MAY BE SOME
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS LATER TONIGHT INTO
THE OVERNIGHT HOURS...BUT OVERALL...WEATHER CONDITIONS WILL BE
IMPROVING ON THURSDAY ACROSS MOST AREAS WITH THE EXCEPTION OF
SEA-BREEZE ENHANCED CONVECTION ACROSS THE COASTAL AND RIO GRANDE
PLAINS.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
UPPER LEVEL RIDGING WILL BE DOMINATING THE REGION LATER IN THE
WEEK INTO THE UPCOMING WEEKEND WITH ONLY SEA-BREEZE ENHANCED
ACTIVITY ACROSS THE SOUTHEASTERN COUNTIES OF SOUTH CENTRAL TEXAS
EACH AFTERNOON THROUGH SUNDAY. A WARMING TREND IS ON THE WAY FOR THE
NEXT SEVERAL DAYS THANKS TO THE UPPER RIDGE. MOSTLY DRY WEATHER
CONDITIONS ARE EXPECTED FROM MONDAY AND TUESDAY OF NEXT WEEK WITH
HIGHS IN THE UPPER 90S TO NEAR 100.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 88 74 95 74 98 / 60 30 20 10 10
AUSTIN BERGSTROM INTL AIRPORT 89 72 95 71 97 / 60 30 20 10 10
NEW BRAUNFELS MUNI AIRPORT 85 71 93 71 95 / 60 30 20 10 -
BURNET MUNI AIRPORT 81 72 91 73 92 / 60 30 20 10 10
DEL RIO INTL AIRPORT 87 74 89 75 92 / 70 50 40 20 10
GEORGETOWN MUNI AIRPORT 86 72 94 73 95 / 60 30 20 10 10
HONDO MUNI AIRPORT 88 73 93 73 95 / 70 40 30 10 -
SAN MARCOS MUNI AIRPORT 85 73 93 72 96 / 60 30 20 10 10
LA GRANGE - FAYETTE REGIONAL 90 74 98 74 96 / 60 30 20 10 20
SAN ANTONIO INTL AIRPORT 85 75 93 75 95 / 60 30 20 10 -
STINSON MUNI AIRPORT 85 73 93 74 95 / 70 30 30 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...01
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...12
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1150 PM CDT TUE JUL 16 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
PLENTY OF EARLIER RAINFALL MAY LEAD TO AT LEAST MVFR CONDITIONS
LATER TONIGHT. FOR NOW...THE GUIDANCE AND CURRENT OBSERVATIONS
INDICATE WIDESPREAD VFR IS MORE LIKELY. IF MVFR CONDITIONS DO
DEVELOP...EXPECT THESE TO IMPROVE BY AROUND 14Z. OTHERWISE...AN
UPPER LOW OVER THE WESTERN GULF WAS APPEARING TO SHEAR OUT ON THE
WATER VAPOR. MOISTURE WAS BEING FOCUSED ACROSS THE NORTHWESTERN
GULF INTO SE TX AROUND THIS SYSTEM TOWARD A STRONGER UPPER LOW
OVER NORTHERN NM. THE MODELS ARE NOT IN GOOD AGREEMENT AS TO THE
DETAILS...BUT DO EXPECT SHOWERS TO PERSIST THROUGH MIDDAY ON
WEDNESDAY WITH ANOTHER CHANCE FOR THUNDERSTORMS DURING THE
AFTERNOON. THE MODELS THEN AGREE WITH DRYING WEDNESDAY EVENING.
40
&&
.PREV DISCUSSION... /ISSUED 832 PM CDT TUE JUL 16 2013/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
00Z SOUNDINGS WERE VERY MOIST WITH PW VALUES 2.36 AT CRP AND 2.22
AT LCH. 850 MB MOISTURE WAS ALSO ROBUST WITH 850 TD BETWEEN 15 C
AND 19 C. A LARGE UPPER LOW WAS LOCATED OVER EAST CENTRAL NEW
MEXICO AND A SMALL SCALE WEAK UPPER LOW WAS NOTED NEAR MATAGORDA
BAY. FEEL THE WEAKER SYSTEM NEAR MATAGORDA BAY WAS ENHANCING THE
INFLOW AND HELPING TO FOCUS THE MOISTURE INTO A NARROW CHANNEL
FEEDING INTO SE TX. ALREADY BUMPED POPS UP IN THE COASTAL COUNTIES
FROM 00-06Z AND WILL CARRY CHANCE POPS FROM 06-12Z. THE RAP AND
HRR ARE ONCE AGGRESSIVE WITH MORNING SHRA/TSRA ALONG THE COAST.
WILL LEAVE HIGH END CHANCE POPS IN PLACE AND RE-EVALUATE ONCE 00Z
MODELS COME IN. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 73 90 73 93 73 / 40 50 30 20 10
HOUSTON (IAH) 74 90 75 93 74 / 40 50 20 20 20
GALVESTON (GLS) 79 89 80 91 79 / 50 50 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1156 PM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN HOT AND HUMID CONDITIONS INTO
TOMORROW. A COLD FRONT WILL MOVE SOUTHWARD OVER THE AREA...WHICH
WILL STALL OVER VIRGINIA AND NORTH CAROLINA TO KEEP THE THREAT FOR
SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 1150 PM EDT THURSDAY...
ONE ISOLATED AREA OF TSRA PERSISTS IN NORTH CENTRAL NC...OTHERWISE
ALL ACTIVITY HAS DISSIPATED. THIS AREA CONTINUES TO DEVELOP ON ITS
OWN OUTFLOW. ALL OF THE SYNOPTIC SCALE MODELS AND THE HRRR SHOW
THIS DISSIPATING WITHIN THE NEXT HOUR OR TWO. MODIFIED POPS IN
THIS AREA SLIGHTLY TO ACCOUNT FOR THIS CONTINUING...BUT HOPEFULLY
THAT SHOULD BE IT AFTER 06Z UNTIL MID TO LATE MORNING FRIDAY. T/TD
READINGS AND CLOUD COVER APPEAR TO BE ON TRACK.
AS OF 350 PM EDT THURSDAY...
THANKS TO A SUFFICIENTLY HOT AND HUMID AIR MASS OVERHEAD FROM A
DEPARTING STRONG UPPER LEVEL RIDGE...SCATTERED SHOWERS AND
THUNDERSTORMS FIRED ALONG AND WEST OF THE BLUE RIDGE...WITH THE
MOST CONCENTRATED AREAS IN TAZEWELL COUNTY OF VIRGINIA AND
GREENBRIER COUNTY OF WEST VIRGINIA. THE STORMS CONTINUE TO MOVE
WESTWARD ALBEIT QUITE SLOWLY AT THIS TIME. AFTER SUNSET...THE
SEVERE THREAT SHOULD SUBSIDE AS THE CONVECTION DISSIPATES. FOG
SHOULD OCCUR ONCE AGAIN IN THE FAVORED RIVER VALLEYS BY EARLY
FRIDAY MORNING.
ONCE THE MORNING FOG FADES...FRIDAY SHOULD BE ANOTHER HOT AND
HUMID DAY...ALTHOUGH HIGH TEMPERATURES DO NOT VENTURE AS FAR
UPWARD COMPARED TO HIGHS FROM THE PREVIOUS DAY DUE TO A SMALL
REDUCTION IN 500 HPA HEIGHTS. A BLEND OF THE MAV AND MET MOS
GUIDANCES WAS USED FOR THE FORECAST TEMPERATURES. BASED ON MODEL
SOUNDINGS...THERE WILL STILL BE SUFFICIENT INSTABILITY TO TRIGGER
MORE AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY...WITH THE BEST
POPS IN THE WESTERN MOUNTAINS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 300 PM EDT THURSDAY...
UPPER TROF DEVELOP ENOUGH BY SATURDAY FOR SOME UPPER DIFFLUENCE OF
THE FORECAST AREA. MODELS KEEP THIS ENHANCED LIFT OVER THE REGION
THROUGH SUNDAY MORNING.
BY FRIDAY NIGHT 850 MB WINDS ARE FROM THE WEST AROUND 20 KNOTS AND
THE LOW LEVEL FLOW REMAINS LIKE THIS THROUGH SUNDAY. THIS IS
FAVORABLE FOR DEVELOPMENT OF SHOWER AND THUNDERSTORMS IN THE WESTERN
COUNTY WARNING AREA AND SOME WARMER TEMPERATURES DUE TO DOWNSLOPING
IN THE LEE OF THE BLUE RIDGE. TEMPERATURES IN THE MID LEVELS COOL
SLIGHTLY WHICH SHOULD ALSO RESULT IN MID LEVEL LAPSE RATES THAT
SUPPORT THUNDERSTORMS.
SURFACE FRONT APPROACHING FROM THE NORTH GETS CLOSE ENOUGH TO
PROVIDE SOME LOW LEVEL CONVERGENCE IN THE NORTHERN COUNTY WARNING
AREA ON SUNDAY. ALSO STILL SEEING THE POTENTIAL FOR LEE TROFING AD
LOW LEVEL CONVERGENCE ALONG AND JUST EAST OF THE BLUE RIDGE ON BOTH
SATURDAY AND SUNDAY. APPEARS BEST COVERAGE WILL BE IN THE WESTERN
COUNTY WARNING AREA ON SATURDAY AFTERNOON AND EVENING AND IN THE
EASTERN COUNTY WARNING AREA SUNDAY AFTERNOON AND EVENING.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 1240 PM EDT THURSDAY...
BROAD UPPER TROF OVER THE NORTHEAST UNITED STATES THIS TIME FRAME.
SHORT WAVES COMES THROUGH THE BASE OF THE TROF AND ACROSS THE OHIO
VALLEY ON TUESDAY. PATTERN IS NOT VERY AMPLIFIED AND 00Z ECMWF IS
SUGGESTING SURFACE FRONT WILL REACH THE FORECAST AREA SATURDAY NIGHT
AND SUNDAY...THEN WITH WAVES MOVING ALONG THE BOUNDARY BACK AND
FORTH THROUGH THE FORECAST AREA INTO WEDNESDAY.
850 MB TEMPERATURES REMAIN IN THE +16 TO +19 RANGE. BUT EXPECTING
ENOUGH CLOUDS AND PRECIPITATION TO KEEP TEMPERATURES NEAR NORMAL.
WILL CONTINUE TO HIGHLIGHT PROLONGED PERIOD OF WET WEATHER WITH THE
POTENTIAL FOR HEAVY RAIN AND FLOODING IN THE HAZARDOUS WEATHER
OUTLOOK.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
AS OF 745 PM EDT THURSDAY...
WHAT LITTLE CONVECTION THERE WAS TODAY...MAINLY WEST OF THE BLUE
RIDGE HAS DIMINISHED OR ENDED. WILL REMOVE ALL MENTION OF TSRA
FROM LYH/ROA/DAN TAFS. WEST OF THE BLUE RIDGE...ISOLD SHRA/TSRA
ACTIVITY WILL CONTINUE FOR A COUPLE MORE HOURS...BUT GIVEN LACK OF
ANY WIDESPREAD UPPER/SYNOPTIC SUPPORT AND THE UPPER RIDGE
OVERHEAD...DO NOT EXPECT IT TO CONTINUE MUCH LONGER. THUS...WILL
KEEP VCTS IN FOR BLF/BCB WHERE ISOLD SHRA/TSRA LINGER THROUGH
02Z...THEN DROP. WITH A STAGNANT AIR MASS...DEWPOINTS AOA
70F...AND CLEARING SKIES...EXPECT DEVELOPMENT OF FOG IN THE USUAL
LOCATIONS TONIGHT. LWB/BCB SHOULD BOTH SEE LIFR VSBY/CIGS IN FG
ABT 06Z CONTINUING THROUGH 13Z. FOR THE REMAINING SITES...EXPECT
MAINLY MVFR TO POTENTIALLY IFR AT LYH/DAN...EXCEPT ROA...WHICH
SHOULD REMAIN VFR. FOR FRI...THE DEEPER MOISTURE WILL SPREAD BACK
EAST AS THE UPPER RIDGE CONTINUES TO WEAKEN AND A WEAK DISTURBANCE
DRIFTS TOWARD THE REGION FROM THE TN VALLEY. OVERALL...EXPECT AN
INCREASE IN COVERAGE OF SHRA/TSRA ACTIVITY FRI AFTERNOON...AND THE
ACTIVITY SHOULD SPREAD ACROSS THE ENTIRE CWA BY EVENING...AS
OPPOSED TO TODAY WHEN IT WAS CONFINED JUST TO THE WESTERN AREAS.
WINDS CALM OR VRB03KT OVERNIGHT...BECOMING SW-WSW FRI AT SPEEDS OF
5-7KTS.
MEDIUM TO HIGH CONFIDENCE ON CIGS/VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN TSRA POTENTIAL FRI AFTERNOON.
AS OF 145 PM EDT THURSDAY...
VFR CONDITIONS WITH LIGHT WINDS SHOULD PERSIST THROUGH THIS
AFTERNOON...BUT SOME ISOLATED SHOWERS AND THUNDERSTORMS WILL FIRE
ALONG AND WEST OF THE BLUE RIDGE. VCTS WAS INSERTED FOR
LWB/BLF/BCB/ROA AND LEFT OUT AT LYH/DAN DUE TO LACKING LOW LEVEL
CONVERGENCE IN THE PIEDMONT. AFTER SUNSET...CONVECTION SHOULD
WANE...BUT PATCHY FOG SHOULD DEVELOP AFTER MIDNIGHT. GIVEN THE
TREND OF THE LAST FEW NIGHTS AND THE MOIST GROUND...CONFIDENCE IS
GOOD FOR IFR/LIFR FOG AT LWB AND BCB. MODEL GUIDANCE IS LESS
CONFIDENT FOR THE DEVELOPMENT OF DENSE FOG AT THE OTHER SITES...SO
MVFR/IFR FOG WAS UTILIZED. THE EXCEPTION WAS ROA...WHERE MENTION
OF FOG WAS OMITTED FOR NOW DUE TO MORE OPTIMISTIC GUIDANCE THERE.
VFR CEILINGS AND VISIBILITIES SHOULD RESUME BY FRIDAY MORNING.
HOWEVER...A DAILY THREAT OF AFTERNOON SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THIS WEEKEND...AS A COLD FRONT MOVES
SOUTHWARD OVER THE AREA. FLYING WEATHER APPEARS MOST PESSIMISTIC
DURING SATURDAY EVENING THROUGH SUNDAY EVENING WHEN THE FRONT
CROSSES OVERHEAD...AND PROVIDES MVFR/IFR CONDITIONS FROM SHOWERS
AND THUNDERSTORMS. LONG RANGE MODELS SHOW THE COLD FRONT STALLING
OVER THE CAROLINAS BY MONDAY...WHICH WOULD KEEP THE THREAT OF
AFTERNOON CONVECTIVE ACTIVITY THROUGH EARLY NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PW
NEAR TERM...RAB
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...PW/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
332 AM EDT WED JUL 17 2013
.SYNOPSIS...
STRONG UPPER LEVEL HIGH PRESSURE ACROSS THE REGION WILL CONTINUE
TO DRIFT WEST AND WEAKEN THROUGH THE WEEK. WEAK UPPER LEVEL
DISTURBANCES WILL ROTATE SOUTH INTO THE AREA THROUGH THURSDAY
RESULTING IN WIDELY SCATTERED SHOWERS AND STORMS AT TIMES. A COLD
FRONT WILL SINK INTO THE OHIO VALLEY NEAR THE END OF THE WEEK
BEFORE SLIDING SOUTH ACROSS THE REGION LATER THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM EDT WEDNESDAY...
OUTFLOW BOUNDARY...DEEP MOISTURE CONVERGENCE AND HIGHER THETA-E
RIDGE REFIRING CONVECTION IN THE VA PIEDMONT EARLY THIS MORNING. 00Z
NAM WAS ABOUT THE ONLY MODEL TO KEEP CONVECTION GOING
OVERNIGHT...BUT USUAL BIAS OF TOO MUCH COVERAGE. LATEST HRRR HAS
NOTHING AT THE MOMENT BUT FIRES UP SOME TOWARD 08Z ACROSS SOUTHSIDE
VA/NW NC PIEDMONT. WILL HANG ONTO ISOLATED SHRA/TSRA TO JUST BEFORE
DAWN BUT EXPECT THINGS TO WEAKEN AGAIN BY THEN.
FOR TODAY...MODELS SHOW MAIN FOCUS FOR CONVECTION ACROSS THE
MOUNTAINS WITH LESS COVERAGE IN THE PIEDMONT. WENT CLOSER TOWARD THE
GFS/LOCAL WRF AND NAM...WITH HIGHER POPS ALONG THE SRN BLUE RIDGE
AND POINTS WEST WITH THINGS FIRING UP BY MIDDAY. STORM MOTION STILL
SHOULD BE IN A NE TO SW PATTERN AROUND 10-20 KNOTS...ALTHOUGH HEAVY
RAINERS ARE EXPECTED WITH PWATS RUNNING FROM 1.5 TO 1.75 INCHES.
THERE WILL BE ENOUGH INSTABILITY AROUND THAT SIMILAR TO
TUESDAY...SOME SVR PULSE STORMS ARE POSSIBLE WITH DAMAGING DOWNBURST
WINDS AND MARGINAL SVR HAIL POSSIBLE. AT THIS TIME...LOOKS LIKE THE
AREAS FROM SRN WV INTO THE NC MTNS AND EAST ACROSS THE NC/VA
PIEDMONT HAVE THE BETTER THREAT FOR SVR ALBEIT ISOLATED. WILL
MAINTAIN MENTION OF THIS THREAT IN THE HWO.
KEPT HIGH TEMPS CLOSE TO TUESDAY/S ALTHOUGH SOME CIRRUS THIS MORNING
PLUS STORMS FIRING UP EARLIER MAY KEEP A FEW AREA TEMPS DOWN A FEW
DEGREES. WITH THE FORECAST HIGHS IN THE MID 90S EAST OF THE DAN/LYH
AREA...HEAT INDICES ARE GOING TO TOP AROUND 100 THIS AFTERNOON
OUTSIDE ANY STORM. THIS WILL ALSO BE KEPT IN THE HWO.
TONIGHT...THE THINKING IS THE STORMS WEAKEN AGAIN AND FADE BY
MIDNIGHT AS THEY EXIT TO THE SOUTHWEST. MAY STILL SEE SOME POP UPS
OVER THE SWRN CWA AFTER MIDNIGHT. LOWS TONIGHT WILL STAY MUGGY WITH
NO CHANGE IN AIRMASS...MID TO UPPER 60S MOUNTAINS TO LOWER TO MID
70S EAST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT WEDNESDAY...
THIS MORNING THE FORECAST WILL NOT INTRODUCE MUCH CHANGE TO THIS
SEGMENT OF THE FORECAST AS COMPARED TO WHAT WAS OFFERED ON TUESDAY
AFTERNOON. THE PATTERN TREND THROUGH THE PERIOD WILL REFLECT HIGH
PRESSURE OVER THE OHIO VALLEY REGION BEING DISPLACED TO THE
SOUTHWEST IN RESPONSE TO AN APPROACHING TROUGH ALONG THE
U.S/CANADIAN BORDER. THE RESULT WILL BE A GRADUAL TREND TOWARD
SLIGHTLY COOLER TEMPERATURES...BUT STILL A COUPLE DEGREES ABOVE
NORMAL FOR THIS TIME OF THE YEAR. ALSO...WE ANTICIPATE DAILY
SCATTERED SHOWERS AND STORMS TO DEVELOP AS LOW LEVEL FLOW BECOMES
MORE SOUTHERLY AND CAN TAP THE EASTERN PART OF THE GULF OF MEXICO.
AS WE PROGRESS INTO THE WEEKEND....THE NORTHERN STREAM UPPER TROUGH
WILL BRING AN ASSOCIATED SURFACE COLD FRONT INTO THE REGION. THIS
WILL ALLOW FOR COVERAGE TO BE MORE THAN SCATTERED ACROSS THE
REGION...ESPECIALLY ACROSS SOUTHEAST WEST VIRGINIA WEST WHERE LIKELY
PROBABILITIES OF PRECIPITATION ARE ALREADY BEING OFFERED IN THE
FORECAST SATURDAY AFTERNOON THROUGH THE EVENING HOURS.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 1235 PM EDT TUESDAY...
RETURN TO THE EASTERN UPPER TROF REGIME WILL BE UNDERWAY STARTING
THIS WEEKEND WITH THE AXIS OF THE 5H COOL POOL CROSSING THE
REGION FROM THE NW BY EARLY MONDAY. WEAK COLD FRONT IN BACKDOOR
FASHION JUST NORTH OF THE AREA SUNDAY. FORECAST PWATS QUICKLY
INCREASE BY SUNDAY AS THE FRONT SLOWS AND THE FLOW TURNS MORE SW.
INTERACTION WITH AN EASTERN LEE TROF AND HEATING AHEAD OF THE
PREVIOUS PRE-FRONTAL BAND SHOULD HELP ENERGIZE CONVECTION
ALONG/EAST OF THE BLUE RIDGE SUNDAY SO BUMPING POPS TO HIGH
CHC/LOW LIKELYS ESPCLY SE INCLUDING DECENT CHANCES ACROSS THE
WEST. SOME COOLING LIKELY SUNDAY UNDER MORE MOISTURE/SW FLOW AND
A QUICKER INIT TO CONVECTION DURING THE AFTERNOON.
LOTS OF UNCERTAINTY THEN EARLY NEXT IN JUST HOW FAR SOUTH THE
LOW LEVEL BOUNDARY WILL GET GIVEN THE EXITING/WEAKENING 5H TROF.
APPEARS WITH AT LEAST SCTD CONVECTION MONDAY...PER THE ACTUAL
FRONT OVERHEAD...MAY SEE ENOUGH PUSH TO PERHAPS DRIFT THE
BOUNDARY INTO THE CAROLINAS MONDAY NIGHT BEFORE IT STARTS TO HEAD
BACK NORTH TUESDAY AHEAD OF THE NEXT UPSTREAM WAVE. GIVEN
POTENTIAL FOR MOISTURE TO LINGER LONGER...WONT LEAN TOWARD THE
DRIER GFS...AND KEEP SOME COVERAGE OF POPS GOING MONDAY INTO
TUESDAY WITH LESS CHANCES NORTH-NW SECTIONS MONDAY NIGHT WHERE
SOME DRYING ALOFT MAY SNEAK IN. EXPECT WILL BE BLEEDING IN SOME
SLIGHTLY COOLER AIR AS WELL EARLY NEXT WEEK ALLOWING HIGHS
TO FALL TO SLIGHTLY BELOW NORMAL WITH LOWS INTO THE 60S MOST
SPOTS.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AS OF 130 AM EDT WEDNESDAY...
NOT EXPECTING ANY SHOWERS THIS MORNING WITH LONE ONE 30 MILES
NORTH OF LYH STARTING TO FADE.
AREA OF DENSE CIRRUS FROM CONVECTION WILL KEEP FOG FORMATION AT
TIMES LIMITED...AND THE DENSE FOG WE HAVE AT LWB NOW WILL IMPROVE
SOME TO IFR...BUT THEN AS THE CIRRUS STARTS TO FADE WILL DROP BACK
DOWN AGAIN...SO ONLY HAVE TEMPO GROUP FOR THE IMPROVED VSBYS.
WHERE IT RAINED TUESDAY EVENING...EXPECT FOG FORMATION AROUND
09Z-12Z WITH ALL SITES BUT BLF GETTING AT TIMES INTO IFR WHILE
LWB/BCB FALL MORE.
AS WITH THE LAST COUPLE MORNINGS...FOG WILL LIFT AND BURN OFF
AROUND 12-14Z. GENERALLY VFR CONDITIONS EXPECTED OUTSIDE OF THE
SCATTERED DIURNALLY DRIVEN THUNDERSTORMS. BRIEF PERIODS OF
MVFR/IFR CONDITIONS ASSOC WITH THESE STORMS. CONFIDENCE HIGH
ENOUGH TO HAVE VCTS IN THE TAFS BUT EMPHASIS FOR CONVECTION WILL
MORE OVER THE WV MTNS WED AFTERNOON FADING AGAIN BY 01-03Z.
CYCLE OF FOG CONTINUES WED NIGHT-THU MORNING AT THE USUAL
LOCATIONS AND IN AREAS THAT RECEIVE RAIN WED AFTN.
FOR THURSDAY AND BEYOND...PROGRESSIVELY MORE COVERAGE OF STORMS
THROUGH THE WEEK AS THE UPPER RIDGE FLATTENS AND A TROUGH STARTS
TO BUILD SOUTH INTO THE GREAT LAKES. ALSO...THE COASTAL TROUGH
WILL STRENGTHEN A BIT WITH THE UPPER HIGH CENTERING OVER THE
ROCKIES. A BOUNDARY WILL BE SINKING INTO THE OHIO VALLEY THIS
WEEKEND. SOME MVFR/IFR VIS/CIG CAN BE EXPECTED AT BCB/LWB EACH
DAY...POTENTIALLY REDUCED CIG/VIS DUE TO THUNDERSTORMS AT THE END
OF THE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...DS
LONG TERM...JH
AVIATION...KK/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1146 AM CDT WED JUL 17 2013
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 1145 AM CDT WED JUL 17 2013
NOTICED A FEW SMALL ECHOES ON RADAR AROUND 16Z. HRRR FROM 13Z
INDICATED QUITE A FEW SPECKLES ACROSS THE AREA AROUND THIS TIME.
IN ADDITION...LOCAL MESOANALYSIS GRAPHICS INDICATED LITTLE OR NO
CONVECTIVE INHIBITION AT 16Z WITH SBCAPES OF 1000-2000J/KG IN THE
NORTH AND IN EXCESS OF 3000J/KG IN EAST CENTRAL WISCONSIN. HAVE
GONE WITH AT LEAST ISOLATED THUNDERSTORMS ACROSS THE ENTIRE AREA
FOR THESE REASONS. SPC UPDATED DAY 1 OUTLOOK TO INCLUDE A SLIGHT
RISK OF SEVERE STORMS IN THE FAR NORTH.
&&
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 407 AM CDT WED JUL 17 2013
UPPER RIDGE CENTERED OVER NORTHERN INDIANA AND
ILLINOIS IS FORECAST TO REMAIN NEARLY STATIONARY TODAY AND TONIGHT
BEFORE BEING PUSHED TO THE SOUTHEAST THURSDAY AS THE SOUTHERN EDGE OF
THE WESTERLIES MOVES SOUTHWARD. THE 500MB HEIGHTS OF 599 DM ARE
SOME OF THE HIGHEST IN RECENT MEMORY AND WOULD GENERALLY BE AT THE
CENTER OF A WELL CAPPED ENVIRONMENT THAT WOULD INHIBIT MOST CLOUD
FORMATION AND PRECIPITATION. NOT SO THIS TIME AS 850MB AND 500MB
TEMPERATURES ARE NOT THAT WARM GIVEN THE 500MB HEIGHTS. SOME
EVENTS WITH SIMILAR UPPER AIR AND SURFACE PATTERNS WERE AUGUST 1ST
AND 12TH OF 1988 AND JULY 21ST OF 1987. THOSE DATES HAD HEAT
INDICES OF 100+ GENERALLY SOUTH OF WAUSAU TO GREEN BAY...SO WILL
EXPAND HEAT ADVISORY TO INCLUDE MARATHON...SHAWANO AND MENOMINEE
COUNTIES.
LOTS OF MOISTURE AVAILABLE FOR PRECIPITATION TODAY AND TONIGHT BUT
NOT MUCH IN THE WAY OF TRIGGERS. SOME WEAK FORCING WAS PRODUCING
MIDDLE CLOUDS OVER CENTRAL AND EAST CENTRAL WISCONSIN AT 09Z.
THINK THERE WILL BE AT LEAST ISOLATED CONVECTION TODAY AND MODEL
SEEM TO FAVOR EASTERN WISCONSIN LIKELY DUE TO LAKE BREEZES AND
CONVERGENCE NEAR THE LAKE AND BAY SHORES. HIGHS TODAY SHOULD BE A
DEGREE OR SO ABOVE YESTERDAY.
UPPER HEIGHTS BEGIN TO FALL OVER NORTHERN WISCONSIN TONIGHT AS AN
ASSOCIATED SURFACE BOUNDARY DRIFTS SOUTH. THINK THIS BOUNDARY WILL
NOT MAKE AS MUCH SOUTHWARD PROGRESS AS THE UPPER FLOW IS NEARLY
PARALLEL TO THE SURFACE BOUNDARY. THAT SET UP MIGHT SET THE STAGE
FOR SOME TRAINING OF THUNDERSTORMS OVER FAR NORTHERN WISCONSIN
TONIGHT.
AN APPROACHING UPPER TROUGH SHOULD HELP PRODUCE AT LEAST SCATTERED
THUNDERSTORMS THURSDAY. CLOUD COVER AND SCATTERED STORMS MAY HOLD
TEMPERATURES DOWN A BIT BUT FOR NOW AM KEEPING THEM CLOSE TO WHAT
WE HAVE TODAY.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 407 AM CDT WED JUL 17 2013
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS IS THE MAIN ISSUE
THURSDAY NIGHT AND FRIDAY. INCREASING 0-6 KM SHEAR OF 30 TO 45 KNOTS
WILL SUPPORT STRONG OR SEVERE THUNDERSTORMS...ESPECIALLY ACROSS
THE NORTH THURSDAY EVENING AND INTO THE OVERNIGHT HOURS. QUESTION
IS HOW FAR SOUTH CONVECTION WILL SAG OVERNIGHT. THE MAIN THREAT WOULD
BE DAMAGING WINDS...ALTHOUGH SOME SUPER CELLS COULD PRODUCE MARGINALLY
LARGE HAIL. PRECIPITABLE WATER SHOULD BE 150 TO 200 PERCENT OF NORMAL...
THUS TORRENTIAL RAINS SHOULD BE EXPECTED WITH THE STRONGER STORMS.
SEVERE POTENTIAL FOR FRIDAY IS MUDDLED DUE TO ONGOING CONVECTION/OUTFLOW
BOUNDARIES...CLOUD COVER AND IF WE WOULD RECOVER LATER IN THE AFTERNOON.
STILL SOME UNCERTAINTY IF ONGOING CONVECTION WILL CONTINUE FRIDAY MORNING
OR WANE AND THEN REDEVELOP FRIDAY AFTERNOON. IF WE DO GET SOME SUNSHINE...
LOWERING WET BULB HEIGHTS BETWEEN 10 AND 11 THOUSAND FEET...AND 0-6KM
SHEAR OF 35 TO 45 KNOTS WOULD SUPPORT SUPER CELLS WITH LARGE HAIL...DAMAGING
WINDS. COULD NOT RULE OUT AN ISOLATED TORNADO DUE TO THE STRONG SHEAR
AND LINGERING OUTFLOW BOUNDARIES/LAKE BREEZE INTERACTIONS.
CONTINUED A LINGERING CHANCE OF SHOWERS AND STORMS ACROSS THE EAST
FRIDAY EVENING. MUCH COOLER AND MUCH LESS HUMID AIR WILL WORK INTO
THE REGION SATURDAY. DEW POINTS BY SUNDAY WILL BE IN THE MIDDLE 40S
TO LOWER 50S...OR ABOUT 20 DEGREES LOWER THAN DEW POINTS ON
WEDNESDAY AND THURSDAY.
FORECAST BECOMES MUDDLED AGAIN LATER IN THE WEEKEND INTO THE
MIDDLE PORTION OF NEXT WEEK. SOME TIMING DIFFERENCES NOTED IN THE MODELS
WITH RETURN FLOW PRECIPITATION. HELD OFF PRECIPITATION UNTIL
SUNDAY NIGHT FOR NOW. PREVAILING NORTHWEST FLOW AND RIPPLES MOVING THROUGH
THE MEAN FLOW COULD BRING A CHANCE OF SHOWERS AND STORMS EACH DAY
MONDAY THROUGH WEDNESDAY. AFTER SLIGHTLY BELOW NORMAL TEMPERATURES THIS
WEEKEND...TEMPERATURES SHOULD RETURN CLOSE TO NORMAL EARLY NEXT
WEEK.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1037 PM CDT TUE JUL 16 2013
NO REAL CHG TO AVIATION FCST REASONING. EXPECT MVFR FG TO DEVELOP
AGAIN TNGT...WITH MAYBE SOME BRIELY LOWER CONDITIONS AT GRB/ATW
WHERE RAINS OCCURED LATE THIS AFTN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 5 PM CDT FRIDAY FOR WIZ020-030-031-035>040-
045-048>050.
&&
$$
UPDATE.........MG
SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1121 PM MDT THU JUL 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM MDT THU JUL 18 2013
MAIN CONCERN IS THE POTENTIAL FOR HEAVY RAIN MAINLY ON FRIDAY. THIS
AFTERNOON...WATER VAPOR IMAGERY IS SHOWING THE MSTR PLUME MAINLY OVR
FAR WRN CO...BUT PLENTY OF SHOWERS AND TSTMS HAVE POPPED UP ALONG
THE CONTDVD. SOME OF THE STORMS HAVE BRIEFLY BEEN STRONG...LIKELY
PRODUCING SMALL HAIL AND HEAVY RAIN. OVR THE ERN MTS...SO FAR THERE
HAVE ONLY BEEN SOME ISOLD STORMS. STEERING FLOW ALOFT IS EASTERLY
AND THUS THE STORMS ARE MOVING TOWARD THE WEST. NOT EXPECTING
CONVECTION TO DEVELOP OVR THE SERN PLAINS...BUT LOCATIONS ALONG THE
I-25 CORRIDOR WILL PROBABLY SEE SOME ACTIVITY THIS EVENING. THE NAM
HAS BEEN CONSISTENT IS SHOWING SCT PCPN DEVELOPING THIS EVENING OVR
EL PASO AND PUEBLO COUNTIES...WHILE THE HRRR AND RAP13 SHOW ONLY
SOME ISOLD ACTIVITY. THERE IS THE POTENTIAL THIS EVENING FOR
STRONGER STORMS TO PRODUCE HEAVY RAIN...SO WL HAVE TO KEEP AN EYE ON
ANYTHING THE DEVELOPS OR MOVES OVR THE ANY OF THE BURN SCARS. AFTER
MIDNIGHT THERE COULD BE JUST SOME ISOLD SHOWERS/TSTMS LINGERING THRU
THE NIGHT IN A FEW AREAS...BUT THE CENTRAL MTS...TELLER...EL
PASO...FREMONT AND PUEBLO COUNTIES WL HAVE THE BEST CHANCES OF
SEEING SOME LINGERING CONVECTION.
MODELS SHOWING A SFC LOW DEVELOPING OVR THE SE CORNER OF
CO...CAUSING THE SFC WINDS TO BE NORTHEASTERLY UPSLOPE...AND LOW
LEVEL MSTR WL BE IN PLACE AS WELL. MODELS ARE STILL CONSISTENT
ON DEVELOPING PCPN IN THE MORNING HOURS OF FRI ALONG THE I-25
CORRIDOR AND THE HYR TRRN...WITH SOME ACTIVITY OVR THE FAR SERN
PLAINS BY LATE AFTERNOON. PRECIPITABLE WATER VALUES ARE NOT
FORECAST TO BE AS HIGH FOR FRI AS WHAT THEY WERE SHOWING THE LAST
COUPLE DAYS FOR FRI...AND NOT AS HIGH AS THEY WERE WHEN THERE WAS
FLASH FLOODING LAST WEEKEND. HOWEVER...THERE WILL STILL BE THE
POTENTIAL FOR LOCALLY HEAVY RAIN WITH STRONGER STORMS ON FRI AND
THUS FLASH FLOODING IS STILL A CONCERN...ESPECIALLY OVR THE BURN
SCARS. THE FLOW ALOFT ON FRI WL BE NORTH TO NORTHEAST AND THUS
STORMS ARE EXPECTED TO MOVE TOWARD THE SOUTH OR SOUTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM MDT THU JUL 18 2013
LONGER TERM METEOROLOGICAL CHALLENGES INCLUDES POPS AND
TEMPERATURES. FRIDAY NIGHT INTO SATURDAY SATURDAY SHOULD
EXPERIENCE CONTINUED ELEVATED POPS(ESPECIALLY OVER SOUTHERN AND
WESTERN SECTIONS) AS WELL AS NEAR SEASONAL TEMPERATURES BEFORE
SOMEWHAT WARMER AND DRIER CONDITIONS DEVELOP OVER THE FORECAST
DISTRICT FROM LATER IN THE WEEKEND INTO NEXT WEEK.
LATEST LONGER TERM COMPUTER SIMULATIONS AND FORECAST SOUNDINGS
INDICATE THAT ROUNDS OF BASICALLY SCATTERED SHOWERS AND
THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND BURN
SCAR ISSUES(ESPECIALLY OVER WESTERN AND SOUTHERN SECTIONS) WILL BE
POSSIBLE FROM FRIDAY NIGHT INTO SATURDAY NIGHT IN WAKE OF
NORTHERLY SURGE ALLOWING INCREASED ATMOSPHERIC MOISTURE/PRECIPITABLE
WATER VALUES. WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY.
THEN...A DEVELOPING RIDGE OF HIGH PRESSURE INITIALLY CENTERED OVER
WESTERN NEVADA AT 00Z MONDAY IS PROJECTED TO BECOME CENTERED OVER
SOUTHERN COLORADO BY 00Z THURSDAY BEFORE SHIFTING SOUTHEAST INTO
THE TEXAS PANHANDLE BY 00Z FRIDAY.
AS THIS OCCURS...ANTICIPATE THAT POPS WILL BECOME MORE ISOLATED
FROM SUNDAY INTO NEXT WEEK IN COMBINATION WITH WARMER TEMPERATURES.
SPEAKING OF TEMPERATURES...NEAR SEASONAL MAXIMUM TEMPERATURES ARE
ANTICIPATED SATURDAY WITH ABOVE SEASONAL MAXIMUM TEMPERATURES THEN
PROJECTED OVER THE FORECAST DISTRICT FROM SUNDAY INTO THURSDAY.
MAXIMUM TEMPERATURES OVER PORTIONS OF THE SOUTHEASTERN PLAINS MAY
CHALLENGE THE CENTURY MARK AT TIMES...ESPECIALLY FROM MONDAY INTO
THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1120 MDT THU JUL 18 2013
VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE
REST OF TONIGHT WITH ISOLATED SHRA/TSRA CONTINUING TO DIMINISH
ACROSS THE HIGHER TERRAIN. ALS PICKED UP SOME RAIN THIS
EVENING...THOUGH THERE LOOKS TO BE ENOUGH MID AND HIGH LEVEL
CLOUDS TO KEEP FOG FROM FORMING OVERNIGHT. SHOWERS AND
THUNDERSTORMS WILL BE ON THE UPSWING EARLY FRIDAY MORNING AS A
WEAK DISTURBANCE EMBEDDED WITHIN THE MONSOON MOISTURE PLUME MOVES
SOUTH ACROSS THE STATE. COULD SEE SHOWERS AND THUNDERSTORMS
AFFECTING COS AND PUB BETWEEN 16Z-21Z AND THROUGH THE AFTERNOON
FOR ALS. MVFR AND BRIEF IFR CONDITIONS WILL BE POSSIBLE WITH
LOCALLY HEAVY RAINFALL. HAVE KEPT VCTS IN THROUGH THE LATE
AFTERNOON WITH CONVECTION LIKELY WINDING DOWN THROUGH THE EVENING.
$$
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
402 AM EDT Fri Jul 19 2013
.NEAR TERM [Today and Tonight]...
As has been advertised for the past couple days, we should be seeing
a deep plume of tropical moisture arrive this morning. GOES blended
precipitable water product shows the highest values lurking just
offshore in the northeast Gulf of Mexico - on the order of 2.2 to
2.4 inches. This is actually not entirely unreasonable, as the 00z
TBW sounding last evening sampled a 2.36" PWAT. The HRRR, other
convection-allowing models (CAM), and even the global models show
our PWATs increasing into this range later today. Forecast soundings
also show a very deep warm cloud layer and weak flow in the
mid-upper levels. Such environments can support very efficient rain
production due to warm-rain processes, as well as backbuilding and
quasi-stationary heavy rain bands.
The global models are not really projecting much QPF over the next
24 hours, and our current grids only call for about 1-2" of rain
through Saturday evening. However, CAM guidance and the HRRR do
indicate localized maxima as high as 6-8" through tonight. Given
that the environment can support very heavy rainfall, and the QPF
signatures on the CAM guidance, we have issued a Hydrologic Outlook
for all of our Florida zones. A Flash Flood Watch may become
necessary depending on how things evolve during the daytime hours.
For the forecast: PoPs were nudged up slightly again and "heavy
rainfall" wording was inserted near the Florida Big Bend where
models agree the best chances for heavy rain exist. Highs were kept
similar to the inherited forecast and the HRRR - with low 80s near
the Big Bend coast, to upper 80s in the northern third of our area.
PoPs were kept above MOS overnight with warm temperatures as we may
not see the usual diurnal cycle given the tropical air mass. In
fact, our local WRF-ARW shows a band of heavy rain persisting
through much of the night in parts of our Florida zones.
&&
.SHORT TERM [Saturday Through Sunday]...
It appears as though yet another wet and unsettled weekend is in
store for the Tri-State area once again, as the persistent Synoptic
scale pattern which keeps advecting deep layer tropical moisture
into the region from the Gulf of Mexico (shown well on the blended
TPW satellite product) will continue for much of the period. As
mentioned above, if this level of moisture (with PWATS again over
2") is productive enough to generate heavy rainfall, Flooding could
once again become a primary concern for parts of the CWA (as some
areas in the eastern FL panhandle have recently received between 15
to 20" of rain! On Sunday, there is "some" hope that both Sfc and
Upper level ridging will push far enough northward to at least bring
PoPs back closer to climo, before the seemingly never ending
troughing becomes re-established across the SE U.S by early mid
week. Even after 19 years of forecasting at WFO TAE (where the Sea
Breeze is typically the primary inducer of convection), the last 2
summers have been quite the aberration in my opinion. Therefore, it
remains to be seen if a somewhat more "typical" summertime pattern
can become established across the region before another summer has
gone by the wayside.
&&
.LONG TERM [Sunday Night through Wednesday]...
Deep layer ridging will dominate the first part of the extended
range forecast, with typical sea breeze patterns and rain chances
through Monday. Thereafter, a trough will nose into the Southeast,
nudging the mid/upper layer ridge out over our Gulf waters.
Additionally, some form of surface reflection will slip into the
Tri-State region and assist in the development of more widespread
shower and thunderstorm development through the remainder of the
period.
&&
.AVIATION [through 12 UTC Saturday]...
VFR conditions currently prevail at the TAF sites, and that is the
way that most of the available guidance portrays the next 24 hours.
However, with a very moist, tropical air mass moving into the area
and fairly widespread rain expected - that may be a little too
optimistic. We did insert some periods of MVFR this afternoon at all
of the terminals with +RA possible. This may not be reduced enough,
but confidence on location and timing of the heaviest rain was low.
Therefore, pilots and flight planners can expect increasing MVFR
over the region during the day, with IFR possible in and near the
heavier rain showers and storms.
&&
.MARINE...
Light to moderate southerly winds will continue to impact the
coastal waters, through Saturday, as an area of low pressure
gradually exits the region. By Sunday, and the remainder of the
period, high pressure at the surface should dominate, keeping winds
and seas on the light side, with possible enhancements nearshore
with the Sea Breeze, but this may not occur if conditions become and
remain too disturbed aloft.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
A plume of deep tropical moisture is shifting toward the northeast
gulf coast early this morning, and will overspread the interstate
10 corridor in Florida by midday. within this plume of tropical
moisture, bands of heavy rain or thunderstorms are expected to
develop and increase in coverage through the day. in environments
such as this, heavier showers and thunderstorms can produce a
considerable amount of rainfall in a short period of time.
Average rainfall totals through Saturday evening across the
Florida panhandle and big bend should be on the order of 1 to 2
inches. That amount of rainfall would generally be insufficient to
produce much flooding across the area. However, localized rain
totals could be quite a bit higher where heavier rain bands or
thunderstorms can persist for more than an hour. Isolated totals
in excess of 4 inches, perhaps as high as 6 to 8 inches, cannot
be ruled out. Rainfall such as that could contribute to localized
flooding, particularly in urban and low lying areas, and on
rivers that are already experiencing high flows such as the St.
Marks Aucilla rivers.
A Flash Flood Watch could become necessary later today if model
guidance becomes more supportive of localized very heavy rain
amounts.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 83 74 88 73 92 / 70 50 60 30 40
Panama City 84 77 86 76 88 / 60 50 60 30 40
Dothan 88 74 88 72 89 / 50 40 60 30 50
Albany 89 73 88 73 90 / 50 40 60 30 50
Valdosta 85 73 90 74 92 / 70 50 60 30 50
Cross City 83 74 87 72 89 / 70 60 60 30 40
Apalachicola 82 77 86 77 86 / 70 60 60 30 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES,
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Gould
LONG TERM...Harrigan/Navarro
AVIATION...Lamers
MARINE...Gould
FIRE WEATHER...Lamers
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS TOPEKA KS
500 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI JUL 19 2013
EARLY THIS MORNING A BROAD UPPER LEVEL RIDGE AXIS EXTENDED FROM
COAST TO COAST ACROSS THE SOUTHERN CONUS. A CUT OFF UPPER LOW WAS
DRIFTING WEST ACROSS THE NORTHERN GULF OF MEXICO. A SECOND CUT OFF
LOW WAS DRIFTING SOUTHWEST INTO NORTHWEST MEXICO. AN UPPER LEVEL
TROUGH WAS MOVING EAST ACROSS THE NORTHERN PLAINS INTO THE UPPER
MIDWEST.
TODAY AND TONIGHT...THE UPPER RIDGE ACROSS THE WESTERN CONUS WILL
AMPLIFY CAUSING THE FLOW ACROSS THE CENTRAL PLAINS TO BECOME
SLIGHTLY MORE NORTHWESTERLY. THE BEST UPPER LEVEL ASCENT AHEAD OF
THE H5 TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL REMAIN WELL
NORTHEAST OF THE CWA. A WEAK COLD FRONT WILL MOVE SOUTHWARD ACROSS
NE INTO THE NORTHERN COUNTIES OF THE CWA BY 21Z. CONVERGENCE ALONG
THIS FRONT MAY CAUSE ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS THE NORTHERN COUNTIES OF THE CWA. THE 00Z GFS AND TWO
MESOSCALE MODELS...THE RAP AND NON-HYDROSTATIC WRF ARE SHOWING A
LINE OF SCATTERED TO NUMEROUS SHOWERS DEVELOPING AHEAD OF THE FRONT
AND PUSHING SOUTHEAST ACROSS THE REMAINDER OF THE CWA THROUGH THE
EVENING HOURS. WHILE THE ECMWF AND 00Z NAM SHOW ONLY ISOLATED
SHOWERS DEVELOPING ACROSS THE NORTHERN HALF OF THE CWA LATE FRIDAY
AFTERNOON AND EVENING. I`M LEANING MORE TOWARDS THE NAM AND ECMWF
SINCE THERE WILL BE LITTLE IN THE WAY OF UPPER LEVEL SUPPORT SINCE
THE MAIN H5 TROUGH WILL BE DIGGING SOUTHEAST ACROSS THE MIDWEST INTO
THE GREAT LAKES STATES. ATTM...I`LL KEEP THE LOW CHANCE POPS OF 25
TO 35 PERCENT ACROSS MUCH OF THE CWA TONIGHT. THE PRECIP SHOULD END
FROM NORTH TO SOUTH DURING THE EARLY MORNING HOURS OF SATURDAY AS
THE COLD FRONT PUSHES SOUTH OF THE CWA BY 12Z SAT.
SKIES WILL START OUT MOSTLY SUNNY ACROSS THE CWA WITH AN INCREASE IN
CU DURING THE AFTERNOON HOURS. HIGHS WILL REACH THE MID TO UPPER 90S
ACROSS THE CWA. SURFACE DEWPOINTS WILL DECREASE SLIGHTLY DURING THE
AFTERNOON HOURS AS THE BOUNDARY LAYER MIXES DEEPER ACROSS THE
PLAINS. I HAVE AFTERNOON DEWPOINTS IN THE LOWER TO MID 60S...WHICH
SHOULD KEEP HEAT INDICES NEAR THE HIGH TEMPERATURES IN THE UPPER
90S. HEAT INDICES MAY REACH AROUND 100 DEGREES ACROSS THE EASTERN
COUNTIES OF THE CWA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI JUL 19 2013
THE FRONT OR ITS REMNANTS WILL LIKELY REMAIN IN THE AREA THROUGH
EARLY NEXT WEEK. WITH WEST TO NORTHWEST FLOW ALOFT ALSO
DOMINATING...A SERIES OF SHORTWAVE TROUGHS WILL MOVE THROUGH THE
FLOW AND ACROSS THE COUNTY WARNING AREA THROUGH THE EXTENDED
PERIODS...ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE
STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS. ALTHOUGH WILL GO
WITH POPS THROUGH MOST OF THE FORECAST...THE BETTER CHANCES FOR MORE
ORGANIZED/HIGHER COVERAGE CONVECTIVE EVENTS OCCURS DURING TWO
PERIODS. THE FIRST WILL BE WITH A POSSIBLE MCS LATE SATURDAY
NIGHT/EARLY SUNDAY ACROSS MAINLY THE WESTERN CWA AND WITH THE
PASSAGE OF THE SHORTWAVE TROUGH ON THE NOSE OF VEERING LLVL FLOW AND
STRONGER WARM ADVECTION LATE SUNDAY INTO SUNDAY NIGHT. THIS SHOULD
BE FOLLOWED BY A PERIOD OF LOWER POP CHANCES INTO TUESDAY BEFORE
ANOTHER SHORTWAVE TROUGH PASSES AND FRONT MOVES THROUGH THE AREA
WITHIN ANOTHER REGION OF STRONGER WAA ALONG THE EASTERN PERIPHERY OF
A STRONG THERMAL AXIS. WITH BOUNDARY STILL IN THE AREA/OR JUST
SOUTH...WILL KEEP LOW POPS GOING PORTIONS OF THE CWA ON INTO
THURSDAY HOWEVER. TEMPERATURES OVER THE WEEKEND INTO NEXT WEEK WILL
BE CHALLENGING AS THE COUNTY WARNING AREA WILL OFTEN BE ON THE
EASTERN EDGE OF A STRONG LLVL THERMAL AXIS WITH THE LLVL FLOW
FREQUENTLY VEERED. HOWEVER...CLOUDS AND PERIODIC PRECIP CHANCES WILL
BE OFFSETTING FACTORS. FOR NOW...HIGHS WILL GENERALLY BE IN THE LOW
TO MID 90S THROUGH THE FCST. MONDAY AND TUESDAY WILL LIKELY BE THE
WARMEST DAYS WITH SOME UPPER 90S POSSIBLE IN THE WESTERN/SOUTHWEST
CWA. AT THIS POINT HEAT INDICES ON BOTH OF THOSE DAYS SHOULD BE IN
THE 98 TO 102 DEGREE RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 454 AM CDT FRI JUL 19 2013
EXPECT VFR CONDITIONS THROUGH MOST OF THE NEXT 24 HOURS. THERE MAY
BE SOME ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ACROSS THE TAF
SITES. THERE CONTINUES TO BE UNCERTAINTY IN BOTH TIMING AND
COVERAGE OF ANY THUNDERSTORM DEVELOPMENT AT THE TAF SITES THIS
EVENING. THEREFORE...I DID NOT INCLUDE A VCTS IN THE TAFS. ANY
THUNDERSTORMS MAY BRING BRIEF MVFR CEILINGS AND VISIBILITIES TO THE
TAF SITES THIS EVENING.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
358 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI JUL 19 2013
EARLY THIS MORNING A BROAD UPPER LEVEL RIDGE AXIS EXTENDED FROM
COAST TO COAST ACROSS THE SOUTHERN CONUS. A CUT OFF UPPER LOW WAS
DRIFTING WEST ACROSS THE NORTHERN GULF OF MEXICO. A SECOND CUT OFF
LOW WAS DRIFTING SOUTHWEST INTO NORTHWEST MEXICO. AN UPPER LEVEL
TROUGH WAS MOVING EAST ACROSS THE NORTHERN PLAINS INTO THE UPPER
MIDWEST.
TODAY AND TONIGHT...THE UPPER RIDGE ACROSS THE WESTERN CONUS WILL
AMPLIFY CAUSING THE FLOW ACROSS THE CENTRAL PLAINS TO BECOME
SLIGHTLY MORE NORTHWESTERLY. THE BEST UPPER LEVEL ASCENT AHEAD OF
THE H5 TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL REMAIN WELL
NORTHEAST OF THE CWA. A WEAK COLD FRONT WILL MOVE SOUTHWARD ACROSS
NE INTO THE NORTHERN COUNTIES OF THE CWA BY 21Z. CONVERGENCE ALONG
THIS FRONT MAY CAUSE ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS THE NORTHERN COUNTIES OF THE CWA. THE 00Z GFS AND TWO
MESOSCALE MODELS...THE RAP AND NON-HYDROSTATIC WRF ARE SHOWING A
LINE OF SCATTERED TO NUMEROUS SHOWERS DEVELOPING AHEAD OF THE FRONT
AND PUSHING SOUTHEAST ACROSS THE REMAINDER OF THE CWA THROUGH THE
EVENING HOURS. WHILE THE ECMWF AND 00Z NAM SHOW ONLY ISOLATED
SHOWERS DEVELOPING ACROSS THE NORTHERN HALF OF THE CWA LATE FRIDAY
AFTERNOON AND EVENING. I`M LEANING MORE TOWARDS THE NAM AND ECMWF
SINCE THERE WILL BE LITTLE IN THE WAY OF UPPER LEVEL SUPPORT SINCE
THE MAIN H5 TROUGH WILL BE DIGGING SOUTHEAST ACROSS THE MIDWEST INTO
THE GREAT LAKES STATES. ATTM...I`LL KEEP THE LOW CHANCE POPS OF 25
TO 35 PERCENT ACROSS MUCH OF THE CWA TONIGHT. THE PRECIP SHOULD END
FROM NORTH TO SOUTH DURING THE EARLY MORNING HOURS OF SATURDAY AS
THE COLD FRONT PUSHES SOUTH OF THE CWA BY 12Z SAT.
SKIES WILL START OUT MOSTLY SUNNY ACROSS THE CWA WITH AN INCREASE IN
CU DURING THE AFTERNOON HOURS. HIGHS WILL REACH THE MID TO UPPER 90S
ACROSS THE CWA. SURFACE DEWPOINTS WILL DECREASE SLIGHTLY DURING THE
AFTERNOON HOURS AS THE BOUNDARY LAYER MIXES DEEPER ACROSS THE
PLAINS. I HAVE AFTERNOON DEWPOINTS IN THE LOWER TO MID 60S...WHICH
SHOULD KEEP HEAT INDICES NEAR THE HIGH TEMPERATURES IN THE UPPER
90S. HEAT INDICES MAY REACH AROUND 100 DEGREES ACROSS THE EASTERN
COUNTIES OF THE CWA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI JUL 19 2013
THE FRONT OR ITS REMNANTS WILL LIKELY REMAIN IN THE AREA THROUGH
EARLY NEXT WEEK. WITH WEST TO NORTHWEST FLOW ALOFT ALSO
DOMINATING...A SERIES OF SHORTWAVE TROUGHS WILL MOVE THROUGH THE
FLOW AND ACROSS THE COUNTY WARNING AREA THROUGH THE EXTENDED
PERIODS...ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE
STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS. ALTHOUGH WILL GO
WITH POPS THROUGH MOST OF THE FORECAST...THE BETTER CHANCES FOR MORE
ORGANIZED/HIGHER COVERAGE CONVECTIVE EVENTS OCCURS DURING TWO
PERIODS. THE FIRST WILL BE WITH A POSSIBLE MCS LATE SATURDAY
NIGHT/EARLY SUNDAY ACROSS MAINLY THE WESTERN CWA AND WITH THE
PASSAGE OF THE SHORTWAVE TROUGH ON THE NOSE OF VEERING LLVL FLOW AND
STRONGER WARM ADVECTION LATE SUNDAY INTO SUNDAY NIGHT. THIS SHOULD
BE FOLLOWED BY A PERIOD OF LOWER POP CHANCES INTO TUESDAY BEFORE
ANOTHER SHORTWAVE TROUGH PASSES AND FRONT MOVES THROUGH THE AREA
WITHIN ANOTHER REGION OF STRONGER WAA ALONG THE EASTERN PERIPHERY OF
A STRONG THERMAL AXIS. WITH BOUNDARY STILL IN THE AREA/OR JUST
SOUTH...WILL KEEP LOW POPS GOING PORTIONS OF THE CWA ON INTO
THURSDAY HOWEVER. TEMPERATURES OVER THE WEEKEND INTO NEXT WEEK WILL
BE CHALLENGING AS THE COUNTY WARNING AREA WILL OFTEN BE ON THE
EASTERN EDGE OF A STRONG LLVL THERMAL AXIS WITH THE LLVL FLOW
FREQUENTLY VEERED. HOWEVER...CLOUDS AND PERIODIC PRECIP CHANCES WILL
BE OFFSETTING FACTORS. FOR NOW...HIGHS WILL GENERALLY BE IN THE LOW
TO MID 90S THROUGH THE FCST. MONDAY AND TUESDAY WILL LIKELY BE THE
WARMEST DAYS WITH SOME UPPER 90S POSSIBLE IN THE WESTERN/SOUTHWEST
CWA. AT THIS POINT HEAT INDICES ON BOTH OF THOSE DAYS SHOULD BE IN
THE 98 TO 102 DEGREE RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1156 PM CDT THU JUL 18 2013
EXPECTING VFR CONDITIONS THROUGH THE AVIATION FORECAST PERIOD. A
VERY WEAK BOUNDARY WILL SLIDE SOUTHWARD INTO NORTHERN KANSAS LATE
IN THE TAF PERIOD...HOWEVER IT IS UNLIKELY THAT IT WILL REACH THE
TERMINALS. WINDS MAY BECOME VERY LIGHT AND VARIABLE AS THE
BOUNDARY APPROACHES. EXPECT A FEW THUNDERSTORMS ALONG OR JUST
NORTH OF THE BOUNDARY...HOWEVER THESE STORMS SHOULD REMAIN NORTH
OF THE TERMINALS UNTIL AFTER THIS FORECAST ISSUANCE.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...LEIGHTON
AREA FORECAST DISCUSSION
NWS GOODLAND KS
212 AM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1105 PM MDT THU JUL 18 2013
CONVECTION OVER PHILLIPS AND LOGAN COUNTIES IN COLORADO IS HAVING
A DIFFICULT TIME MOVING INTO YUMA COUNTY. WILL KEEP A MENTION OF
SOME STORMS THROUGH THE NIGHT THERE GIVEN SOME LOW LEVEL MOISTYRE
CONVERGENCE...THOUGH THE HRRR MODEL NEVER BRINGS PRECIPITATION TO
THE COUNTY THROUGH 12Z. SURFACE TROUGH HAS MOVED THROUGH FLAGLER
AND YUMA...AND WILL ADJUST WIND DIRECTIONS OVER THE WESTERN HALF
OF THE FORECAST AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 228 PM MDT THU JUL 18 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
CLEAR. TEMPERATURES HAVE RISEN INTO THE MID 80S TO LOW 90S. GUSTY
SOUTH WINDS CONTINUE THIS AFTERNOON DUE TO A LEE TROUGH OVER CENTRAL
COLORADO AND A HIGH PRESSURE LOCATED TO THE SOUTH. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED OVER THE ROCKIES THIS AFTERNOON. A COLD
FRONT WAS LOCATED TO THE NORTH...IN THE VICINITY OF THE SOUTH DAKOTA
AND NEBRASKA BORDER AND INTO SOUTHWEST WYOMING.
FOR TONIGHT...MODELS INDICATE THAT SOME OF THE SHOWERS AND STORMS
WILL MOVE TO THE EAST OFF THE TERRAIN. UNFORTUNATELY...MODELS SEEM
PRETTY CONSISTENT IN SHOWING THAT ALL OF THE ACTIVITY WILL DIMINISH
BEFORE MOVING INTO THE REGION. THE WEAK COLD FRONT WILL CONTINUE
MOVING TO THE SOUTH TONIGHT...ENTERING THE REGION AROUND MIDNIGHT
WITH A SLOW MOVEMENT TO THE SOUTH THROUGH THE OVERNIGHT HOURS. A FEW
SHOWERS ARE POSSIBLE ALONG THE FRONT TONIGHT...MAINLY IN SOUTHWEST
NEBRASKA AND NORTHEAST COLORADO. LOW TEMPERATURES TONIGHT SHOULD
FALL INTO THE LOW TO UPPER 60S WITH COOLEST TEMPERATURES EXPECTED
OVER EAST COLORADO. GUSTY SOUTH WINDS WILL DIMINISH THIS EVENING AS
THE PRESSURE GRADIENT RELAXES. A PERIOD OF CALM WINDS IS ANTICIPATED
JUST AHEAD OF THE COLD FRONT BEFORE NORTH TO NORTHEAST WINDS OF 5 TO
15 MPH BEGIN IN THE MORNING HOURS.
FOR TOMORROW...THE WEAK COLD FRONT WILL CONTINUE A SLUGGISH
SOUTHWARD PUSH. HIGHER DEWPOINTS THAN PREVIOUS DAYS ARE EXPECTED TO
POOL ALONG AND JUST AHEAD OF THE FRONT. WITH THE INCREASED MOISTURE
AND HIGH TEMPERATURES CLIMBING INTO THE LOW TO MID 90S AHEAD OF THE
FRONT...INSTABILITY AND FRONTAL SURFACE CONVERGENCE SHOULD BE ENOUGH
FOR SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP. EVEN THOUGH
INSTABILITY WOULD BE ENOUGH TO SUPPORT SOME POSSIBLE SEVERE
THUNDERSTORMS...WEAK LAPSE RATES AND LITTLE SHEAR LEAD ONE TO THINK
THAT WIDESPREAD SEVERE WEATHER IS NOT LIKELY. A STRONG STORM OR TWO
IS POSSIBLE BUT THAT SHOULD BE ABOUT IT. WITH PRECIPITABLE WATER
VALUES AROUND 1.5 INCHES AND SLOW STORM MOTIONS...HEAVY DOWNPOURS
SEEM LIKE A GOOD BET FOR THE STRONGER THUNDERSTORMS. WINDS WILL
SHIFT TO THE EAST BEHIND THE WEAK COLD FRONT.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 212 AM MDT FRI JUL 19 2013
GFS HAS TRENDED SLIGHTLY MORE AMPLIFIED AND LESS PROGRESSIVE WITH
THE UPPER LEVEL RIDGE IN THE WEST. THIS KEEPS OUR AREA IN
NORTHWESTERLY FLOW ALOFT WITH EMBEDDED WEAK AND DIFFICULT TO RESOLVE
SHORTWAVES RESULTING IN SOME CONVECTION TUESDAY THROUGH THURSDAY. IN
CONTRAST...ECMWF HAS BEEN CONSISTENT WITH EXPANDING THE UPPER RIDGE
FURTHER EAST AND HAS MORE DRAMATIC 500 MB HEIGHT RISES THE MIDDLE
OF NEXT WEEK...LEADING TO SOME UNCERTAINTY. THE MOST PRONOUNCED
SHORTWAVE IN NORTHWESTERLY FLOW ALOFT IS SHOWN BY BOTH GFS AND
ECMWF AND WILL PASS THROUGH LATE TUESDAY. GFS IS STRONGEST WITH
DEPICTING AN ASSOCIATED SURFACE BOUNDARY THAT MOVES INTO THE
FORECAST AREA TUESDAY EVENING. ADDITIONALLY...COLUMN MOISTURE
INCREASES WITH PWAT VALUES REACHING NEAR 1.5 INCHES. THIS IS A
CHANGE FROM THE PREVIOUS FORECAST AND HAS REQUIRED THE
INTRODUCTION OF SLIGHT CHANCE POP FOR TUESDAY EVENING/OVERNIGHT.
ACCEPTED CR INITIAL TEMPERATURE GRIDS WHICH ARE A REASONABLY GOOD
COMPROMISE BETWEEN THE COOLER MEX MOS MID WEEK AND THE HOTTER
PATTERN THAT ECMWF IS SHOWING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1105 PM MDT THU JUL 18 2013
SURFACE TROUGH WILL MOVE EAST THROUGH EASTERN COLORADO...AND WILL
REACH KGLD AROUND 09Z. THIS WILL SWITCH THE SURFACE WINDS TO THE
WEST. EXPECT WIND SHIFT AT KMCK AROUND 12Z. VFR CONDITIONS WILL
CONTINUE THROUGH THE PERIOD...BUT EXPECT CONVECTION TO DEVELOP
AFTER 18Z. THERE WILL BE CHANCE OF THUNDERSTORMS AT BOTH
KGLD/KMCK...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INDICATE STORMS
IN THE TAFS. IF STORMS DO MOVE OVER THE SITES...VISIBILITIES WILL
DROP TO MVFR OR LOWER IN BRIEF HEAVY RAIN.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...RRH
LONG TERM...BRB
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1105 PM MDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1105 PM MDT THU JUL 18 2013
CONVECTION OVER PHILLIPS AND LOGAN COUNTIES IN COLORADO IS HAVING
A DIFFICULT TIME MOVING INTO YUMA COUNTY. WILL KEEP A MENTION OF
SOME STORMS THROUGH THE NIGHT THERE GIVEN SOME LOW LEVEL MOISTYRE
CONVERGENCE...THOUGH THE HRRR MODEL NEVER BRINGS PRECIPITATION TO
THE COUNTY THROUGH 12Z. SURFACE TROUGH HAS MOVED THROUGH FLAGLER
AND YUMA...AND WILL ADJUST WIND DIRECTIONS OVER THE WESTERN HALF
OF THE FORECAST AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 228 PM MDT THU JUL 18 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
CLEAR. TEMPERATURES HAVE RISEN INTO THE MID 80S TO LOW 90S. GUSTY
SOUTH WINDS CONTINUE THIS AFTERNOON DUE TO A LEE TROUGH OVER CENTRAL
COLORADO AND A HIGH PRESSURE LOCATED TO THE SOUTH. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED OVER THE ROCKIES THIS AFTERNOON. A COLD
FRONT WAS LOCATED TO THE NORTH...IN THE VICINITY OF THE SOUTH DAKOTA
AND NEBRASKA BORDER AND INTO SOUTHWEST WYOMING.
FOR TONIGHT...MODELS INDICATE THAT SOME OF THE SHOWERS AND STORMS
WILL MOVE TO THE EAST OFF THE TERRAIN. UNFORTUNATELY...MODELS SEEM
PRETTY CONSISTENT IN SHOWING THAT ALL OF THE ACTIVITY WILL DIMINISH
BEFORE MOVING INTO THE REGION. THE WEAK COLD FRONT WILL CONTINUE
MOVING TO THE SOUTH TONIGHT...ENTERING THE REGION AROUND MIDNIGHT
WITH A SLOW MOVEMENT TO THE SOUTH THROUGH THE OVERNIGHT HOURS. A FEW
SHOWERS ARE POSSIBLE ALONG THE FRONT TONIGHT...MAINLY IN SOUTHWEST
NEBRASKA AND NORTHEAST COLORADO. LOW TEMPERATURES TONIGHT SHOULD
FALL INTO THE LOW TO UPPER 60S WITH COOLEST TEMPERATURES EXPECTED
OVER EAST COLORADO. GUSTY SOUTH WINDS WILL DIMINISH THIS EVENING AS
THE PRESSURE GRADIENT RELAXES. A PERIOD OF CALM WINDS IS ANTICIPATED
JUST AHEAD OF THE COLD FRONT BEFORE NORTH TO NORTHEAST WINDS OF 5 TO
15 MPH BEGIN IN THE MORNING HOURS.
FOR TOMORROW...THE WEAK COLD FRONT WILL CONTINUE A SLUGGISH
SOUTHWARD PUSH. HIGHER DEWPOINTS THAN PREVIOUS DAYS ARE EXPECTED TO
POOL ALONG AND JUST AHEAD OF THE FRONT. WITH THE INCREASED MOISTURE
AND HIGH TEMPERATURES CLIMBING INTO THE LOW TO MID 90S AHEAD OF THE
FRONT...INSTABILITY AND FRONTAL SURFACE CONVERGENCE SHOULD BE ENOUGH
FOR SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP. EVEN THOUGH
INSTABILITY WOULD BE ENOUGH TO SUPPORT SOME POSSIBLE SEVERE
THUNDERSTORMS...WEAK LAPSE RATES AND LITTLE SHEAR LEAD ONE TO THINK
THAT WIDESPREAD SEVERE WEATHER IS NOT LIKELY. A STRONG STORM OR TWO
IS POSSIBLE BUT THAT SHOULD BE ABOUT IT. WITH PRECIPITABLE WATER
VALUES AROUND 1.5 INCHES AND SLOW STORM MOTIONS...HEAVY DOWNPOURS
SEEM LIKE A GOOD BET FOR THE STRONGER THUNDERSTORMS. WINDS WILL
SHIFT TO THE EAST BEHIND THE WEAK COLD FRONT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 228 PM MDT THU JUL 18 2013
FRIDAY NIGHT ELEVATED CAPE WILL EXIST OVER THE AREA UNTIL THE
OVERNIGHT HOURS...WITH THE BEST CAPE DURING THE EVENING. THERE IS
NO CLEAR AREA OF MID/UPPER LEVEL LIFT BUT THERE IS SOME LOW LEVEL
CONVERGENCE ACROSS THE CENTRAL PART OF AREA. THE ELEVATED CAPE AND
LOW LEVEL CONVERGENCE/WEAK COLD FRONT MAY ALLOW FOR SOME STORMS TO
DEVELOP/CONTINUE...BUT CONFIDENCE AT THIS TIME IS FAIRLY LOW.
THOUGHT ABOUT TRENDING PRECIP. CHANCES ACCORDING TO WHERE THE LOW
LEVEL CONVERGENCE DEVELOPS...BUT INSTEAD KEPT THE BROAD PRECIP.
CHANCES GOING THROUGH THE EVENING. DURING THE OVERNIGHT HOURS THE
LOW LEVEL CONVERGENCE DWINDLES FROM EAST TO WEST AS THE MID LEVEL
MOISTURE AND ELEVATED CAPE DECLINE...SO HAVE PRECIP. CHANCES
TRENDING ACCORDINGLY.
SATURDAY THE LOW LEVEL CONVERGENCE RETURNS TO THE AREA AGAIN.
SOUNDINGS INDICATE THE MID LEVELS MOISTENING DURING THE AFTERNOON.
WILL AGAIN KEEP PRECIP. CHANCES KIND OF BROAD BUT KEEP THEM OVER THE
SOUTH HALF OF THE AREA WHERE THE LOW LEVEL CONVERGENCE IS BETTER.
ONE OF THE MODELS BRINGS IN A COLD POOL/COLD FRONT DURING THE
AFTERNOON FROM THE NORTH. DO NOT HAVE MUCH CONFIDENCE IN THIS
SOLUTION SINCE OTHER MODELS ARE NOT SHOWING IT.
SATURDAY EVENING AN UPPER LEVEL TROUGH AND COLD FRONT MOVE INTO THE
AREA FROM THE NORTH. THE BEST CHANCE FOR PRECIP. WILL BE DURING THE
EVENING OVER ROUGHLY THE EASTERN HALF OF THE AREA WHERE THE BEST
UPPER LEVEL LIFT WILL TRACK ACROSS. OVERNIGHT PRECIP. CHANCES COME
TO AN END AS DRIER AIR MOVES IN BEHIND THE UPPER LEVEL TROUGH.
THE MAIN THREAT FROM ANY STORMS WILL BE HEAVY RAINFALL FRIDAY
EVENING DUE TO MEAN STORM MOTIONS OF 5 TO 10 KTS AND 0-6KM SHEAR OF
10 TO 15KTS. SATURDAY THE 0-6KM SHEAR INCREASES TO 30KTS WHICH WILL
BE MORE FAVORABLE FOR SEVERE THUNDERSTORMS.
SUNDAY THROUGH THURSDAY A COUPLE WEAK COLD FRONTS/SURFACE TROUGHS
ACCOMPANIED BY AN UPPER LEVEL SHORT WAVE TROUGH MOVE ACROSS THE AREA
EARLY IN THE WEEK...BRINGING PRECIP CHANCES TO THE AREA. MID WEEK A
SURFACE TROUGH DEVELOPS OVER THE SOUTHWEST PART OF THE AREA AND
PUSHES NORTH THURSDAY BRINGING ANOTHER ROUND OF PRECIP. CHANCES FOR
THE AREA. HIGH TEMPERATURES FOR THE PERIOD WILL WARM TO ABOVE NORMAL
BY THE START OF THE WORK WEEK THEN COOL DOWN TO NEAR NORMAL BY MID
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1105 PM MDT THU JUL 18 2013
SURFACE TROUGH WILL MOVE EAST THROUGH EASTERN COLORADO...AND WILL
REACH KGLD AROUND 09Z. THIS WILL SWITCH THE SURFACE WINDS TO THE
WEST. EXPECT WIND SHIFT AT KMCK AROUND 12Z. VFR CONDITIONS WILL
CONTINUE THROUGH THE PERIOD...BUT EXPECT CONVECTION TO DEVELOP
AFTER 18Z. THERE WILL BE CHANCE OF THUNDERSTORMS AT BOTH
KGLD/KMCK...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INDICATE STORMS
IN THE TAFS. IF STORMS DO MOVE OVER THE SITES...VISIBILITIES WILL
DROP TO MVFR OR LOWER IN BRIEF HEAVY RAIN.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...RRH
LONG TERM...JTL
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GAYLORD MI
132 AM EDT FRI JUL 19 2013
.SYNOPSIS...
ISSUED AT 358 PM EDT THU JUL 18 2013
ONE MORE DAY OF HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS
NORTHERN MICHIGAN FRIDAY BEFORE A COUPLE OF COLD FRONTS PASSING
THROUGH THE GREAT LAKES WILL COOL THINGS DOWN DRAMATICALLY BY
SATURDAY. PASSAGE OF THESE FRONTS WILL BE ACCOMPANIED BY
THUNDERSTORM ACTIVITY...SOME OF WHICH COULD BE SEVERE OVERNIGHT
AND INTO FRIDAY. THE SEVERE WEATHER THREAT WILL END BY FRIDAY
EVENING...WITH A DRY AND PLEASANT WEEKEND ON TAP.
&&
.UPDATE...
ISSUED AT 113 AM EDT FRI JUL 19 2013
CHANCES FOR PRECIPITATION NEEDED UPDATING FOR TIMING/COVERAGE OF
BAND OF RAIN SHOWERS AND EMBEDDED ISOLATED THUNDER (INSTABILITY
REALLY LESS THAN DESIRABLE). THIS BAND WAS DROPPING THROUGH
EASTERN UPPER AND WILL MAKE IT TO AND THROUGH THE STRAITS...WHILE
A SECONDARY BAND OF SHOWERS BEGINS TO DROP SOUTHWARD AND BACK INTO
EASTERN UPPER AND NE WISCONSIN. LESS CONFIDENCE IN THIS...AS IT
MAY TAKE UNTIL THE DAYLIGHT HOURS FOR THIS TO ARRIVE. THUS...A
LULL IN THE ACTION OVERNIGHT? SKY NEEDED FIXING AS WELL...WITH
CLEAR SKIES ACROSS MOST OF NRN LOWER...AND THIS WILL LIKELY
CONTINUE THROUGH THE NIGHT UNTIL SAID NEXT BAND OF SHOWERS/STORMS
ARRIVES IN THE DAYLIGHT HOURS.
UPDATE ISSUED AT 1005 PM EDT THU JUL 18 2013
SEVERE THUNDERSTORM WATCH CONTINUES LATE THIS EVENING FOR ERN UPR
MICHIGAN AND THE TIP OF THE MITT. CONVECTIVE LINE (LEWP) HAS
SPREAD ACROSS ALL OF ERN UPR MICHIGAN...WITH THE LEADING EDGE NOW
IN THE STRAITS AREA. A FEW STORMS WITHIN THIS LINE HAVE BECOME
VERY STRONG/LOW END SEVERE...BUT DID SHOW AN OVERALL DOWNWARD
TREND IN INTENSITY AS IT ENTERED OUR NRN ZONES. AT THIS
POINT...WILL KEEP THE WATCH GOING GIVEN THE POTENTIAL FOR A FEW
ADDITIONAL STRONG/SEVERE STORMS IN RESPONSE TO STRENGTHEN WIND
SHEAR AS A 45 TO 50 KT JET MAX LEANS INTO THE AREA LATE TONIGHT.
WILL ALSO KEEP AN EYE ON THE NEXT LINE OF CONVECTION NOW MOVING
E/SE THRU CENTRAL LAKE SUPERIOR AS WE HEAD INTO THE OVERNIGHT
HOURS.
UPDATE ISSUED AT 742 PM EDT THU JUL 18 2013
DIURNAL ENHANCEMENT TO CONVECTION IS QUICKLY DIMINISHING WITH THE
APPROACH OF SUNSET...BRINGING AN END TO THE WIDELY SCATTERED
SHOWERS AND STORMS ACROSS ALL OF NRN LWR MICHIGAN. AFTERNOON
CONVECTION OVER LAKE SUPERIOR HAS FURTHER ORGANIZED INTO A LEWP...
EXTENDING FROM JUST NORTH OF WHITEFISH BAY WESTWARD ALONG THE LAKE
SUPERIOR SHORELINE OF CENTRAL AND ERN UPR MICHIGAN. ADDITIONAL
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED AHEAD OF THIS LINE OF
CONVECTION...WITH THESE CELLS AND THE WHOLE LINE MOVING E/SE. THIS
LINE OF CONVECTION WILL SLIDE THRU ERN UPR MICHIGAN AND THE
STRAITS DURING THE BALANCE OF THE EVENING. VELOCITY DATA HAS SHOWN
SOME EMBEDDED AREAS OF ROTATION WITHIN THE THE LINE...AND WILL
CERTAINLY MONITOR RADAR AS THIS LINE SLIDES THRU OUR NRN CWA.
OVERALL AHEAD WILL STRENGTHEN THRU THE NIGHT AS AS 45 TO 50 KT LOW
LEVEL JET MAX LEANS INTO NRN MICHIGAN. PLENTY OF SURFACE BASED
INSTABILITY WILL REMAIN IN TACT AS WE HEAD THRU THE NIGHT...AS
WILL AMPLE 850 MB THETA E.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
HIGH IMPACT WEATHER POTENTIAL: ISOLATED SEVERE THUNDERSTORMS
POSSIBLE THROUGH EARLY EVENING. INCREASING THREAT FOR DAMAGING
WINDS TONIGHT OVER EASTERN UPPER AND THE TIP OF THE MITT...MOVING
SOUTH INTO NORTHERN LOWER MICHIGAN ON FRIDAY.
HOT AND HUMID WEATHER CONTINUES...WITH HEAT ADVISORIES BEING
CONFINED CLOSER TO SAGINAW BAY FOR THE DAY ON FRIDAY AHEAD OF
ARRIVING COLD FRONT.
OVERVIEW: FLAT RIDGING CONTINUES ACROSS THE GREAT LAKES REGION THIS
AFTERNOON WITH STRONGER SHORTWAVE ENERGY NOW BECOMING EVIDENT
DROPPING OUT OF NORTHERN MANITOBA...WITH AN ADDITIONAL WAVE OVER
SOUTHERN SASKATCHEWAN. AT THE SURFACE...LOW PRESSURE HAS TAKEN
SHAPE OVER EASTERN NORTH DAKOTA THIS HOUR WITH QUASI-STATIONARY
WARM FRONT EXTENDING EAST ACROSS NORTHERN MINNESOTA AND UPPER
MICHIGAN. STORMS HAVE PERCOLATED ALONG THIS BOUNDARY ALL DAY GIVEN
SOUPY WARM SECTOR AIRMASS AND SOUTHWESTERLY WINDS RIDING OVER THE
BOUNDARY IN THE PRESENCE OF AMPLE UNCAPPED INSTABILITY AND GRADUALLY
INCREASING DEEP LAYER SHEAR. ON THE MESOSCALE...AND OUTFLOW
BOUNDARY WORKED SOUTH INTO NORTHERN LOWER HELPING TO TRIGGER
CONVECTION SOUTH OF THE FRONT...WITH SOME OF THIS ACTIVITY ONGOING
AS I TYPE. TEMPS IN AREAS NOT SEEING RAINFALL ARE NOT DISAPPOINTING
THE HOT/HUMID TALK OF LATE...WITH TVC 96 AND CAD 97 THIS HOUR.
THROUGH EARLY EVENING: ISOLATED TO SCATTERED TSRA ACTIVITY WILL
CONTINUE OVER NORTHERN LOWER...ALTHOUGH DECREASING IN COVERAGE AS WE
AWAIT FURTHER DEVELOPMENT UPSTREAM.
TONIGHT: BROAD AREA OF HEIGHT FALLS OVERSPREADS THE GREAT LAKES
REGION AHEAD OF STRONG SHORTWAVE WHOSE CORE WILL BE DROPPING THROUGH
NORTHERN MANITOBA. BENEATH THIS FEATURE THE SURFACE LOW WILL TRACK
NORTH AND EAST...TO NEAR THE SOUTHERN SHORE OF JAMES BAY BY DAYBREAK
FRIDAY. HEIGHT FALLS AND TIME OF DAY WILL COAX A STRENGTHENING LLJ
AT H8 FROM NORTHERN WISCONSIN NORTH AND EAST ACROSS LAKE SUPERIOR.
SYNOPTIC SETUP AND SHEAR PARAMETERS CERTAINLY FAVOR PROGRESSIVE MCS
DEVELOPMENT WITH OVER 30KTS OF 0-3KM BULK SHEAR...BUT NO MORE THAN
10KTS ABOVE THIS TO 6KM. THE QUESTION BECOMES...WHERE IS THIS
CONVECTION LIKELY TO FORM/MOVE?
THE SYNOPTICALLY-FAVORED LOCATION WOULD BE NEAR OR JUST NORTH OF LAKE
SUPERIOR GIVEN THE CURRENT FRONTAL BOUNDARY AND EXPECTED LLJ
LOCATION. THIS IS WELL SHOWN BY THE NEW 12Z NAM AND PROBABLY THE
STRONGEST GUIDANCE CONSENSUS WHICH BRINGS TO DISTINCT CONVECTIVE
COMPLEXES OVER OR NORTH OF MY NORTHERN ZONES. AFTERNOON RADAR
TRENDS...HOWEVER...SUGGEST DEVELOPMENT A LITTLE FURTHER SOUTH AND
WEST...OVER THE ARROWHEAD OF MINNESOTA ALONG OUTFLOW BOUNDARY IN
THIS AREA. EARLY AFTERNOON HRRR IS ONTO THIS TREND...AND WITH
FORWARD-PROPAGATING CORFIDI VECTORS SUGGESTING AN ESE STORM
MOTION...LOOKS TO BRING ACTIVITY TOWARDS EASTERN UPPER LATER THIS
EVENING...WITH PERHAPS MORE ACTIVITY DEVELOPING UPSTREAM THROUGH THE
FIRST HALF OF TONIGHT AS THE LLJ STRENGTHENS IMMEDIATELY AHEAD OF
THE SURFACE COLD FRONT. THUS...WILL INCREASE POPS OVER EASTERN
UPPER TO LIKELY DURING THE EVENING HOURS...BUT KEEP LIKELIES
PRIMARILY RESTRICTED TO EASTERN UPPER OVERNIGHT GIVEN EXPECTED STORM
PROPAGATION. SOME ROGUE STORM DEVELOPMENT TO THE SOUTH IS
POSSIBLE...BUT LOWER POPS WARRANTED HERE. SEVERE THREAT IS
THERE...MORE ISOLATED WIND/HAIL IN THE NEAR TERM...WITH A MORE
ORGANIZED WIND THREAT TAKING SHAPE THIS EVENING.
REALLY LIKE INHERITED VERY WARM OVERNIGHT LOWS GIVEN INCREASING
CLOUD COVER AND COUPLED BOUNDARY LAYER FLOW NOT GIVING TEMPERATURES
MUCH ROOM TO FALL. SO...LOOKING LIKE THE LAST UNCOMFORTABLE SLEEPING
NIGHT MAY BE THE WORST /AT LEAST OVER NORTHERN LOWER/ WHERE MID TO
UPPER 70S SHOULD ABOUT DO IT.
FRIDAY: SOMEWHAT UNUSUAL FOR THE APX CWA SO FAR THIS WARM
SEASON...WE HAVE A COLD FRONT PROGGED TO PUSH THROUGH THE FORECAST
AREA IN THE MIDDLE OF PEAK HEATING. CLEARLY...OVERNIGHT CONVECTIVE
ACTIVITY WILL HAVE A HUGE IMPACT ON WHAT HAPPENS THUNDERSTORM-WISE
DURING THE DAY. COULD VERY WELL BE SOME ONGOING ACTIVITY ACROSS THE
CWA EARLY...WITH THE BEST CHANCES AGAIN BEING OVER EASTERN
UPPER...CLOSEST TO THE ARRIVING COLD FRONT. THIS AT LEAST SPELLS
THE POTENTIAL FOR SOME DESTABILIZATION AHEAD OF AFOREMENTIONED COLD
FRONT /ESP OVER NORTHERN LOWER/ WHICH LOOKS TO PUSH THROUGH THE CWA
IN THE 18-00Z TIME FRAME. SHEAR PARAMETERS ARE IMPRESSIVE AS THE
PRIMARY BELT OF THE WESTERLIES SINKS INTO OUR AREA. 0-3KM BULK
SHEAR REACHES 40KTS...WITH 50KTS+ OF 0-6KM SHEAR. SHEAR LOOKS TO
ONLY HAVE A SLIGHT ANGLE TO THE ARRIVING BOUNDARY...SO A LINEAR MODE
WITH EMBEDDED BOWING SEGMENTS COULD CERTAINLY BE SUPPORTED. THIS IS
WELL CAPTURED BY THE DAY 2 SLIGHT RISK AREA FROM SPC.
AS FOR TEMPERATURES AND HEAT ADVISORY CONCERNS...THE EARLIER
EXPANSION OF THE HEAT ADVISORY TO THE SOUTHEASTERN ZONES FOR THE DAY
LOOKS RIGHT ON...GIVEN STRENGTHENING SOUTHWEST WINDS GIVING SOME
DOWNSLOPING ASSISTANCE TO THESE AREAS...WHICH SHOULD PUSH TEMPS INTO
THE LOW/MID 90S BEFORE CONVECTIVE ACTIVITY ARRIVES FROM THE NORTH
AND WEST. ELSEWHERE...LOW TO MID 80S LOOK GOOD GIVEN EXPECTED CLOUD
COVER AND RAINFALL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
RECENT TRENDS...TEMPERATURES: HOT...OBVIOUSLY. 1-3C ABOVE NORMAL
LAST 7 DAYS AND PRETTY MUCH FOR THE MONTH OF JULY THUS FAR.
PRECIPITATION/HYDROLOGY: BAND OF HEAVIER PRECIPITATION ACROSS
EASTERN UPPER/STRAITS REGION LAST NIGHT (RADAR ESTIMATES 3+ INCHES
FAR WESTERN MACKINAC/SCHOOLCRAFT COUNTIES) MOST SUBSTANTIAL RAINFALL
OF LAST SEVEN DAYS...OUTSIDE OF SCATTERED DIURNAL ACTIVITY MUCH OF
NORTHERN LOWER MICHIGAN HASN`T SEEN A DROP. 30 DAY STANDARDIZED
PRECIP INDEX CONTINUING TO TREND DRIER...ESPECIALLY ACROSS PORTIONS
OF UPPER MICHIGAN THAT SAW GOOD RAINS OVERNIGHT. STREAMFLOWS ON
AREA RIVERS STILL MOSTLY NEAR NORMAL...HYDROGRAPHS FLAT GIVEN LACK
OF RENEWED RUNOFF. TOPSOIL MOISTURE STILL IN GOOD SHAPE DESPITE
RECENT DRYNESS.
LARGE SCALE PATTERN/FORECAST...CONTINENTAL U.S. DOMINATED BY FLAT
RIDGING...WITH THE SOUTHERN EDGE OF THE MAIN WESTERLIES RUNNING
STRAIGHT WEST-EAST ALONG THE CANADIAN BORDER. PATTERN MORE BLOCKY
UPSTREAM ACROSS THE PACIFIC WITH "OFF THE CHART" -EPO/-WPO INDICES.
BALL OF ENERGY EMERGING FROM ABOVE THE ARCTIC CIRCLE AND ENTERING
FAR NORTHERN SASKATCHEWAN/MANITOBA THIS AFTERNOON WILL BE THE
CATALYST TO THE END OF THE CURRENT HEAT AND HUMIDITY THAT HAS BEEN
LINGERING OVER THE UPPER LAKES THIS WEEK. STRONG HEIGHT FALLS WILL
DROP ACROSS THE REGION FRIDAY AND DRIVE COOLER AIR INTO MICHIGAN FOR
THE WEEKEND. QUASI-ZONAL FLOW THEN FORECAST TO SET UP ACROSS THE
NORTHERN HALF OF THE CONUS FOR THE FIRST PART OF NEXT WEEK...WITH
SOME LOW AMPLITUDE TROUGHING FROM THE GREAT LAKES/OHIO VALLEY
NORTHEAST INTO NEW ENGLAND.
AHEAD OF THE CANADIAN HEIGHT FALLS WILL BE A PAIR OF COLD FRONTS
THAT WILL SWEEP ACROSS NORTHERN MICHIGAN FRIDAY/FRIDAY NIGHT. THIS
WILL PUSH A REFRESHINGLY COOLER/DRIER AIR MASS INTO THE UPPER LAKES
SATURDAY...WHILE HIGH PRESSURE SETTLES INTO THE REGION FOR SUNDAY.
HIGH PRESSURE RETREATS TO THE EAST MONDAY WITH RETURN FLOW OF WARMER
AIR BACK INTO THE UPPER MIDWEST/UPPER LAKES GETTING UNDERWAY. MAIN
FORECAST CONCERN THROUGH THE WEEKEND WILL BE WITH THE TRANSITION
FROM WARM/MUGGY TO COOLER WEATHER FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SUNDAY: WEATHER...LEAD COLD FRONT WILL LIKELY
STILL BE IN THE VICINITY OF THE M-72/US-10 CORRIDOR FRIDAY
EVENING...WITH CONVECTION (POTENTIALLY SEVERE) LIKELY ONGOING AHEAD
OF THIS BOUNDARY WHICH SHOULD SINK INTO SOUTHERN LOWER MICHIGAN BY
MIDNIGHT. SECONDARY BOUNDARY COMES IN HOT ON ITS HEELS...PUSHED
ALONG BY THE MAIN SHORT WAVE TROUGH THAT WILL BE DIGGING SOUTHEAST.
MUCH OF THE FORCING ALOFT LOOKS TO REMAIN NORTH OF THE FORECAST
AREA...SOME QG SUBSIDENCE CROSSES NORTHERN MICHIGAN BEHIND THE LEAD
FRONT. SO WILL RUN WITH THUNDERSTORM CHANCES BASICALLY SOUTH OF A
MBL-APN LINE FRIDAY EVENING...AND DRY THINGS OUT THEREAFTER HEADING
INTO SATURDAY. WEAK SHORT WAVE TROUGH WILL TRACK THROUGH THE
MIDWEST SUNDAY...WHICH COULD PUSH CLOUDS INTO NORTHWEST LOWER DURING
THE AFTERNOON HOURS.
WINDS...SHIFTING TO THE NORTHWEST BEHIND SECONDARY COLD FRONT EARLY
SATURDAY MORNING...WINDS WILL BE A BIT GUSTY SATURDAY GIVEN GOOD
POST-FRONTAL MIXING (LOW LEVEL COLD ADVECTION/DIURNAL HEATING) ON
THE ORDER OF 20+MPH. WINDS FORECAST TO SETTLE DOWN SATURDAY NIGHT
AS HIGH BUILDS IN AND GRADIENT DROPS OFF. SUNDAY WINDS WILL BE
LIGHT AND DOMINATED BY LAKE BREEZE EVOLUTION.
TEMPERATURES...OVERNIGHT LOWS SHOULD FINALLY BREAK INTO THE 50S
ACROSS EASTERN UPPER AND MUCH OF NORTHWEST/NORTH CENTRAL LOWER
SATURDAY MORNING. SHOULD SEE A NICE DROP IN HUMIDITY EXPECTED
SATURDAY WITH DEW POINTS FALLING INTO THE 40S DURING THE AFTERNOON.
SATURDAY AFTERNOON HIGHS 65-70 EASTERN UPPER...UPPER 60S-LOWER 70S
MUCH OF NORTHWEST LOWER WITH MID-UPPER 70S NORTHEAST LOWER.
SEASONABLY COOL LOWS FOR SUNDAY MORNING WITH TEMPERATURES DROPPING
INTO THE 40S AWAY FROM THE IMMEDIATE LAKESHORES. SUNDAY HIGHS
AROUND 70-MID 70S EXPECTED.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): MIDWEST SHORT WAVE
CURRENTLY LOOKS AS IF IT WILL PASS SOUTH OF LOWER MICHIGAN AND INTO
THE OHIO VALLEY SUNDAY NIGHT/MONDAY. IF THAT IS THE CASE THEN WILL
PROBABLY START THE NEW WORK WEEK WITH A DRY FORECAST. BETTER THREAT
FOR RAIN MAY ARRIVE WITH A COLD FRONT HEADING INTO THE MIDWEEK
PERIOD...THEN WILL START THE NEW THURSDAY FORECAST OUT DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 113 AM EDT FRI JUL 19 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU MOST OF THE 24 HR TAF
FORECAST PERIOD...HOWEVER CHANCES OF SHOWERS AND STORMS WILL
STEADILY INCREASE OVERNIGHT AND INTO FRIDAY AS A COLD FRONT DROPS
SE THRU NRN MICHIGAN. LOW LEVEL SW FLOW WILL CONTINUE TO INCREASE
AHEAD OF THE FRONT...LENDING TO LLWS THRU THIS MORNING. LOW LEVEL
WINDS WILL BE STRONGER IN AND AROUND THUNDERSTORMS. THE COLD FRONT
WILL CLEAR NRN LWR MICHIGAN BY LATE AFTERNOON...WITH MVFR CIGS
DEVELOPING BEHIND THE FRONT FOR THE EVENING HOURS.
&&
.MARINE...
ISSUED AT 130 AM EDT FRI JUL 19 2013
UPDATED THE SMALL CRAFT ADVISORIES TO INCLUDE ALL OF THE NW LOWER
LAKE MICHIGAN NEARSHORES....INCLUDING GRAND TRAVERSE BAY. THIS WAS
ALREADY OUT...BUT TOOK OUT SEUL CHOIX TO THE BRIDGE...AND ADDED
PORTIONS OF LAKE HURON NEARSHORES. GRADIENT WINDS OF 35KTS...EVEN
WITH THE STABILITY...WILL LIKELY RESULT IN LOW END ADVISORY GUSTS
PRIOR TO A COLD FRONTAL PASSAGE FRIDAY.
IN ADDITION...GUSTY OUTFLOW FROM BAND OF SHOWER SAND ISOLATED
THUNDER DROPPING INTO EASTERN UPPER WILL RESULT IN TEMPORARY
ADVISORY LEVEL GUSTS. WILL HANDLE THIS WITH AN MWS. MARGINAL
SCA/S MAY AGAIN BE NECESSARY ON SATURDAY GIVEN STRENGTHENING
NORTHWEST FLOW.
BEHIND THE FRONT FOR FRIDAY NIGHT AND SATURDAY MORNING...THE
STRENGTHENING NW WINDS ARE A RESULT OF A SECONDARY COLD FRONTAL
PASSAGE. HIGH PRESSURE THEN BUILDS IN FOR THE REMAINDER OF THE
WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ016>034.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ035-036-041-042.
LH...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR LHZ349.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...SD
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
459 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM CDT FRI JUL 19 2013
OUR MPX WRF AND HOP WRF ARE ON SIMILAR PATHS WITH THE SHOWER AND
THUNDERSTORM ACTIVITY EXITING OUR AREA BY 12Z. FOR TODAY...A BREAK
FROM THE HEAT AND HUMIDITY WILL BE NOTED WITH SOME SCATTERED
CLOUDS...EXCEPT FOR SOUTHWEST MN WHICH MAY BE CLOUD FREE. VERY DRY
AIR ABOVE 6000 FEET WILL CONTINUE WORKING ITS ITS WAY INTO WESTERN
MN. THERE IS SOME LOW LEVEL MOISTURE ACROSS EASTERN MN AND WESTERN
WI. THE RAP KEEPS THIS MOISTURE IN PLACE UNTIL MID AFTERNOON. SHOULD
BE PLENTY OF MIXING SO DO NOT EXPECT MORE THAN SCATTERED
CLOUDS...EXCEPT SW MN WHERE IT MAY BE CLEAR. MAY BE CLEAR AFTER 21Z
IN MOST AREAS AS DRIER AIR FILTERS IN. OVERNIGHT A SECONDARY COLD
FRONT USHERS IN COOLER AIR AND BY SATURDAY MORNING A DISTURBANCE
MOVES TOWARD WESTERN MN WITH AN INCREASE IN MOISTURE. NO
PRECIPITATION EXPECTED THROUGH 12Z SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM CDT FRI JUL 19 2013
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE RIDGING OVER THE
ROCKIES...WITH EPISODIC IMPULSES PARADING ACROSS THE NORTHERN CONUS.
THE FIRST OF THESE SHORTWAVES HAS BEEN CONSISTENTLY PROGGED TO
ARRIVE ON SATURDAY NIGHT INTO SUNDAY BY DETERMINISTIC AND ENSEMBLE
SOLUTIONS. FAIRLY IMPRESSIVE LIFT FROM 305-310K IS PROGGED TO
BLOSSOM OVER THE AREA BETWEEN 06Z AND 12Z SUNDAY AS 925-850 MOISTURE
TRANSPORT NOSES INTO SOUTHERN MN. HAVE INCLUDED 50-60 POPS FOR THIS
TIME FRAME.
NORTHWEST FLOW PERSISTS THROUGH THE BEGINNING OF NEXT WEEK...WHICH WILL
NECESSITATE THE INCLUSION OF 20-30 POPS FOR A LONG DURATION. THE
TUESDAY INTO WEDNESDAY TIMEFRAME IS TRENDING DRIER HOWEVER...AS
DRY SURFACE HIGH PRESSURE BUILDS IN...SO MAY BE ABLE TO SHED
SHOWER AND THUNDERSTORM CHANCES FOR THOSE DAYS.
WEDNESDAY NIGHT INTO FRIDAY LOOK WET AGAIN HOWEVER....AS SHORTWAVE
ENERGY CHANNELS THROUGH THE WESTERN PERIPHERY OF THE ONTARIO LOW.
TEMPERATURES WILL REMAIN RELATIVELY STATIC THROUGH THE EXTENDED
PERIOD...WITH HIGHS GENERALY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1149 PM CDT THU JUL 18 2013
HAVE SCALED BACK PRECIP CHCS IN THE 06Z ISSUANCE AS MIDLVL RIDGING
HAS PREVENTED MUCH IN THE WAY OF CONVECTIVE DEVELOPMENT FROM
DROPPING S FROM NRN MN. THAT SAID...ISOLD ECHOES HAVE BEGUN TO
SHOW UP IN W-CENTRAL MN ON THE KMPX RADAR. HOWEVER...LATEST SHORT-
TERM MODEL RNUS INDICATE VERY LITTLE TO NEARLY NO CONVECTIVE
ACTIVITY WILL IMPACT THE TERMINALS. LATEST POP UPDATE HAS DROPPED
PRECIP CHCS TO NO HIGHER THAN 30 PERCENT SO HAVE OPTED TO RUN WITH
A DRY FCST WITH CONFIDENCE QUITE LOW IN PREDICTING CONVECTION TO
IMPACT ANY TERMINAL. CLOUD COVER WILL INCRS OVERNIGHT...LIKELY TO
RESULT IN MIDLVL CIGS BUT STILL WELL UP IN VFR RANGE. SKIES WILL
THEN STEADILY CLEAR OUT DURG THE DAY. MAINLY SW WINDS AT
INITIALIZATION IN THE 6-10KT RANGE FROM GRADUALLY VEER TO THE W
AND NW DURG THE DAY. SPEEDS WILL ALSO INCRS TO NEAR 15G25KT.
KMSP...RAN WITH VFR THIS FCST PERIOD AS PRECIP CHCS HAVE BEEN
REDUCED FOR THE FIRST 6 HRS OF THIS FCST. CLOUD COVER IS HARD TO
FIND OVER CENTRAL MN AT INITIALIZATION BUT ADDITIONAL OBS HAVE
STARTED TO REPORT SCT/BKN COVERAGE IN NRN AND W-CENTRAL MN. THESE
WILL GRADUALLY GET INTO MSP DURG THE EARLY MRNG HRS...MAKING FOR A
MIDLVL CIG. IF ANY PRECIP WERE TO OCCUR...BEST TIMING LOOKS TO BE
07Z-10Z...BUT WITH POPS LESS THAN 30 PERCENT...HAVE OPTED TO RUN
WITH A DRY FCST. SKIES THEN GRADUALLY CLEAR OUT STARTING AROUND
DAYBREAK THRU THE REST OF THE DAY. SW WINDS SETTLE DOWN TO THE 5-8
KT RANGE THEN VEER THROUGH DAYBREAK AS A CDFNT SLIPS S ACRS THE
AREA. WINDS GRADUALLY BECOME NW BY LATE MRNG AND INCRS TO THE
15G25KT AREA BEFORE SETTLING DOWN FRI EVE.
/OUTLOOK FOR KMSP/
SAT...MAINLY VFR. SLGT CHC -SHRA/-TSRA. NW WINDS 5-10 KTS.
SUN...MAINLY VFR. CHC -SHRA/-TSRA. SE WINDS 5-10 KTS.
MON...MAINLY VFR. CHC -SHRA/TSRA. S WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...LS
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS DULUTH MN
1245 AM CDT FRI JUL 19 2013
.AVIATION.../00Z TAF ISSUANCE/
VFR CEILINGS WITH VCTS WILL BE COMMON THROUGH THE REMAINDER OF
THE NIGHT AS A COLD FRONT MARCHES EAST ACROSS THE REGION. THE
LINGERING SHOWERS AND STORMS WILL EXIT FRIDAY MORNING WITH
INCREASING NORTHWEST WINDS THROUGH THE DAY. WIDESPREAD GUSTS
AROUND 25 KT WILL BE FOUND BY FRIDAY AFTERNOON WITH MID LEVEL
SCT/BKN CEILINGS.
&&
PREV DISCUSSION... /ISSUED 304 PM CDT THU JUL 18 2013/
SHORT TERM.../THROUGH TONIGHT/
THE FOCUS IS ON THE THREAT OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING. THE STORM PREDICTION CENTER HAS POSTED ALL OF THE
NORTHLAND IN AT LEAST A SLIGHT RISK OF SEVERE THUNDERSTORMS...AND
A MODERATE RISK ACROSS THE SOUTHERN HALF OF THE FORECAST AREA.
LARGE HAIL AND HEAVY RAIN MAY BE THE INITIAL MAIN THREATS AND THEN
QUICKLY TRANSITIONING TO A DAMAGING WIND THREAT. THE
MODELS...ESPECIALLY THE HIGH RESOLUTION HRRR AND NCEP WRF
SIMULATED REFLECTIVITY RUNS...HAVE BEEN INDICATING SUPERCELL
THUNDERSTORMS WILL LIKELY DEVELOP IN NW AND NORTH CENTRAL
MINNESOTA LATE THIS AFTERNOON OR EARLY THIS EVENING...AND THEN
CONGEAL INTO A LINE OF STORMS THAT SWEEP THROUGH THE NORTHLAND
THIS EVENING. A SEVERE THUNDERSTORM WATCH WILL LIKELY BE ISSUED
WITHIN THE NEXT HOUR OR SO.
THIS AFTERNOON AND EVENING...MUCH OF THE NORTHLAND HAS HOT AND
MUGGY WEATHER WITH GUSTY SW WINDS AS A FRONT STRETCHES ACROSS
WESTERN ONTARIO TO A LOW IN THE NORTHERN RED RIVER VALLEY. A
STRONG COLD FRONT EXTENDS FROM SW FROM THE LOW THROUGH THE CENTRAL
DAKOTAS. MOST OF THE NORTHLAND...SAVE FOR THE FAR NORTH AND OVER
THE LAKE...HAS DEVELOPED AMPLE SURFACE BASED CAPE UP TO AROUND
3500 J/KG...MAXIMIZED ACROSS THE S AND SW FORECAST AREA. THERE IS
LITTLE IF ANY INHIBITION. DEEP LAYER (0-6KM) WIND SHEAR OF 30 TO
50 KNOTS HAS DEVELOPED...WITH THE HIGHEST SHEAR ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. PRECIPITABLE WATER VALUES ARE
AROUND 1.75 TO 2 INCHES. THERE SHOULD BE INCREASING CHANCES OF
SHOWERS AND STORMS ACROSS THE FORECAST AREA THROUGH THE REST OF
THE AFTERNOON...BUT THE FOCUS WILL BE ON THE WESTERN FORECAST AREA
WHERE THE MODELS HAVE BEEN INDICATING THUNDERSTORMS...LIKELY AT
FIRST SUPERCELLS...WILL DEVELOP IN NW AND NORTH CENTRAL MINNESOTA
LATE THIS AFTERNOON NEAR THE LOW PRESSURE SYSTEM AND APPROACHING
COLD FRONT. CONSIDERING THE AVAILABLE CAPE...CAPE SOUNDING
PROFILES...AND DEEP LAYER WINDS...THE SUPERCELLS COULD EASILY
DEVELOP LARGE HAIL...GUSTY WINDS...AND HEAVY RAIN. A STRAY TORNADO
CANNOT BE RULED OUT. THE STORMS MAY QUICKLY CONGEAL...AS THE
MODELS SUGGEST...INTO A LINE OF STORMS WITH A TRANSITIONING THREAT
TO MAINLY DAMAGING WINDS AND HEAVY RAIN. THIS LINE AND COLD FRONT
COULD SWEEP ESE THROUGH THE REST OF NE MINNESOTA AND THEN NW
WISCONSIN PRETTY QUICKLY THIS EVENING. I ADDED WORDING TO THE
FORECAST TO INCLUDE SEVERE THUNDERSTORMS AND THE LIKELY THREATS
FOR WHEREVER MY PCPN CHANCES ARE LIKELY LATE THIS AFTERNOON
THROUGH AROUND MIDNIGHT...WHICH IS BASICALLY MY BEST GUESS ON THE
HOURLY TIMING OF THE MAIN LINE OF THUNDERSTORMS.
LATE TONIGHT...THE SEVERE WEATHER THREAT SHOULD COME TO AN END
AROUND MIDNIGHT AS THE MAIN LINE OF STORMS MOVES SE OF THE
FORECAST AREA...BUT THERE COULD BE SOME LINGERING SHOWERS AND
STORMS ACROSS THE SE FORECAST AREA NEAR THE FRONT. THERE SHOULD
ALSO BE DECREASING CHANCES OF SHOWERS AND STORMS FROM NW TO
SE...BUT I LEFT LOW CHANCES OF SHOWERS AND STORMS ACROSS MOST OF
THE FORECAST AREA SINCE A SHORTWAVE WILL LIKELY MOVE INTO THE
NORTHERN FORECAST AREA LATE TONIGHT. THIS SHORTWAVE COULD HELP
DEVELOP SOME MORE SHOWERS AND STORMS.
LONG TERM.../FRIDAY - WEDNESDAY/
THE WEST-NORTHWEST FLOW OF COOLER AND DRIER AIR WILL BE
ESTABLISHED OVER THE FORECAST AREA BY FRIDAY MIDDAY. THERE WILL
BE SOME LINGERING SHOWERS LEFT OVER FRIDAY MORNING BEFORE ENDING
BY MIDDAY. THE WEST TO NORTHWEST FLOW WILL CONTINUE INTO SATURDAY
BUT A WEAK SHORTWAVE WILL CAUSE A POSSIBILITY OF SHOWERS ACROSS
THE REGION. THE RIDGE WILL MOVE EAST AND A RETURN FLOW OF MOISTURE
TO THE FORECAST AREA ON SUNDAY. THIS WILL CONTINUE INTO MIDWEEK
WITH WEAK SHORTWAVES PASSING THROUGH THE FLOW. THIS WILL KEEP A
CHANCE FOR PRECIP ACROSS THE FORECAST AREA FOR THE TIME PERIOD.
TEMPS WILL BE NEAR NORMAL THROUGH MOST OF THE WEEK.
&&
.POINT TEMPS/POPS...
DLH 52 70 49 69 / 10 10 20 20
INL 46 69 48 73 / 10 10 10 10
BRD 55 75 52 76 / 10 10 20 30
HYR 53 75 50 74 / 10 10 20 20
ASX 52 69 48 70 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR MNZ011-012-
019>021.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS BISMARCK ND
352 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE OUTSIDE OF
THUNDERSTORMS. INCLUDED VCTS FOR KISN AND KMOT BY 22-00
UTC...CONTINUING THEREAFTER AS ISOLATED TO SCATTERED THUNDERSTORMS
ARE POSSIBLE ALONG A COLD FRONT MOVING SOUTH FROM CANADA. KEPT
THE MENTION OF THUNDERSTORMS OUT FOR KDIK...KBIS AND KJMS FOR NOW
DUE TO UNCERTAINTY...AND WILL RE-EVALUATE WITH THE 12 UTC CYCLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1246 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1246 AM CDT FRI JUL 19 2013
NO CHANGES REQUIRED WITH THIS UPDATE OTHER THAN TO BLEND TO THE 05
UTC OBSERVED TRENDS IN THE WAKE OF THE COLD FRONT PROPAGATING INTO
NORTHEAST MINNESOTA THROUGH SOUTHWEST SOUTH DAKOTA.
UPDATE ISSUED AT 942 PM CDT THU JUL 18 2013
UPDATE TO REDUCE LATE EVENING POPS AND CONFINE AREA FROM THE
TURTLE MOUNTAINS THROUGH FOSTER COUNTY. STRONG STORMS GLANCED THE
FAR NORTHEAST EARLIER THIS EVENING BUT HAVE SINCE DISSIPATED WHILE
CONVECTION CONTINUES TO THE EAST. CANNOT RULE OUT AN ISOLATED
STORM OVER THE NEXT FEW HOURS...BUT THE PROBABILITY IS LOW.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE MAIN FORECAST CONCERN FOR THE PERIOD WILL BE THUNDERSTORM
CHANCES THIS AFTERNOON AND EVENING AS WELL AS THE SEVERE POTENTIAL.
HEAT INDEX VALUES APPROACHING 100 DEGREES WILL CONTINUE ACROSS THE
SOUTHERN JAMES RIVER BASIN AHEAD OF A COLD FRONT THROUGH THE LATE
AFTERNOON. THEREFORE...WILL MAINTAIN THE CURRENT HEAT ADVISORY IN
EFFECT THROUGH 00Z.
IN ADDITION...THUNDERSTORMS ARE STILL PROGGED TO DEVELOP OVER THE
JAMES RIVER BASIN IN AN AREA OF LARGE INSTABILITY CHARACTERIZED BY
SURFACE-BASED CAPE VALUES OF 2500 J/KG. HOWEVER...MARGINAL TO LOW
DEEP LAYER SHEAR IS EXPECTED TO KEEP THIS CONVECTION BELOW SEVERE
LIMITS. THIS ACTIVITY SHOULD BE OUT OF THE JAMES RIVER BASIN BY 00Z
THIS EVENING AS THE COLD FRONT PUSHES EAST OF THE CWA.
AN UPPER WAVE OVER NORTHWESTERN NORTH DAKOTA WILL PIVOT ACROSS THE
STATE TONIGHT. ONGOING CONVECTION OVER THE SOUTHERN CANADIAN PRAIRIES
IS EXPECTED TO ENTER NORTH CENTRAL NORTH DAKOTA AFTER 23Z AS THE
WAVE PIVOTS ACROSS THE REGION. THE 3KM HRRR AND 12Z WRF KEEP THE
CONVECTION CONFINED TO AREAS NORTHEAST OF HIGHWAY 52 THROUGH 03Z.
SOME STORMS MIGHT ALREADY BE SEVERE AS THEY CROSS THE BORDER.
HOWEVER...THE SEVERE THREAT SHOULD DIMINISH AFTER 03Z WITH THE LOSS
OF DAYTIME HEATING. WILL THEREFORE INTRODUCE SEVERE WORDING IN THE
GRIDS FOR THE 23Z-03Z PERIOD FOR POINTS NORTH OF A LINE FROM MOHALL
TO DEERING TO BALTA. FURTHERMORE...WILL CONTINUE TO HIGHLIGHT THIS
THREAT IN THE HWO. AFTER 03Z...DRY CONDITIONS ARE EXPECTED AREAWIDE
AS HIGH PRESSURE BUILDS INTO THE REGION. MUCH COOLER OVERNIGHT LOWS
ARE EXPECTED WITH READINGS FROM THE MID 50S WEST TO THE LOWER 60S
SOUTHEAST.
FOR FRIDAY...HIGH PRESSURE WILL SLOWLY SINK SOUTHWARD INTO SOUTH
DAKOTA. AS IT DOES...A WEAK BAROCLINIC ZONE IS PROGGED TO SET UP
OVER NORTHERN NORTH DAKOTA. THIS FEATURE SHOULD PROVIDE FOCUS FOR
AFTERNOON CONVECTION. GIVEN THE ELEVATED NATURE OF THE THUNDERSTORM
POTENTIAL...THINK ANY CONVECTION THAT DOES DEVELOP WILL STAY BELOW
SEVERE LIMITS. TEMPERATURES WILL BE MORE SEASONAL FRIDAY WITH HIGHS
FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A NORTHWEST UPPER
LEVEL FLOW PATTERN WITH PERIODIC EMBEDDED SHORTWAVES MOVING THROUGH
THE FLOW. AT THIS TIME THE LONG TERM MODELS ARE DEPICTING SHORTWAVES
MOVING THROUGH THE FORECAST AREA EACH DAY...KEEPING ISOLATED TO
SCATTERED THUNDERSTORM ACTIVITY/CHANCES EACH DAY.
THE LONG TERM BEGINS FRIDAY NIGHT WITH ANOTHER SURFACE COLD FRONT
MOVING SOUTHWARD DURING THE DAYTIME FRIDAY...BECOMING STATIONARY
FRIDAY NIGHT/SATURDAY AS DRY HIGH PRESSURE MOVES INTO NORTHEASTERN
NORTH DAKOTA. EXPECT SCATTERED THUNDERSTORMS ALONG THIS BOUNDARY
FROM NORTHWEST TO SOUTH CENTRAL/SOUTHEASTERN NORTH DAKOTA. PLENTY OF
CAPE BUT LIMITED SHEAR WILL KEEP THE MENTION OF SEVERE STORMS OUT OF
THE FORECAST.
THE NEXT CHANCE OF SCATTERED THUNDERSTORMS APPEARS TO BE SUNDAY
AFTERNOON/NIGHT...THEN AGAIN MONDAY AFTERNOON/NIGHT. AT THIS TIME IT
APPEARS THAT WEDNESDAY MAY SEE A BREAK IN THE ACTION WITH DRY
SURFACE HIGH PRESSURE DEPICTED AND A LULL IN THE SHORTWAVES ACROSS
NORTH DAKOTA...BUT TIMING IS VERY IFFY WITH TIMING OF SHORTWAVES.
ANOTHER SHORTWAVE WITH A SURFACE TROUGH/FRONT TRAVERSES THE FORECAST
AREA THURSDAY.
THUS ISOLATED TO SCATTERED THUNDERSTORMS NEARLY EACH DAY. THE
COOLEST DAY SHOULD BE SATURDAY WITH HIGHS FROM THE 70S ALONG AND
NORTH AND EAST OF THE MISSOURI RIVER WITH LOW TO MID 80S SOUTH AND
WEST OF THE RIVER. OTHERWISE SEASONABLE TEMPERATURES WITH HIGHS
MAINLY IN THE 80S AND LOWS IN THE UPPER 50S TO MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1246 AM CDT FRI JUL 19 2013
VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE OUTSIDE OF
THUNDERSTORMS. INCLUDED VCTS FOR KISN AND KMOT BY 22-00
UTC...CONTINUING THEREAFTER AS ISOLATED TO SCATTERED THUNDERSTORMS
ARE POSSIBLE ALONG A COLD FRONT MOVING SOUTH FROM CANADA FRIDAY
EVENING. KEPT THE MENTION OF THUNDERSTORMS OUT FOR KDIK...KBIS AND
KJMS DUE TO UNCERTAINTY...AND WILL RE-EVALUATE WITH THE 12 UTC
CYCLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...TM
LONG TERM...JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1137 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1130 PM CDT THU JUL 18 2013
WIDELY SCATTERED/ISOLATED CONVECTION CONTINUES ACROSS NORTHERN MN
ASSOCIATED WITH SHORT WAVE TRACKING ALONG INTERNATIONAL BORDER.
MAINTAINED SOME CHC POPS ACROSS NE THIRD OF FORECAST AREA FOR A
FEW MORE HOURS BEFORE ANY CONVECTION SHOULD BE SHIFTING EAST OF
FA. CELL ACROSS N BELTRAMI HAS STRENGTHENED SLIGHTLY HOWEVER STILL
BELOW SEVERE LIMITS AND WILL ALLOW WATCH TO EXPIRE AT MIDNIGHT.
TRIMMED POPS FARTHER WEST BEHIND BOUNDARIES FOR REMAINDER OF THE
NIGHT. REMAINDER OF THE FORECAST BASICALLY UNCHANGED AS
TEMPERATURES AND CLOUD TRENDS ON TRACK.
UPDATE ISSUED AT 945 PM CDT THU JUL 18 2013
CONVECTION STRUGGLED ALL EVENING TO GET GOING ACROSS EASTERN FA
ALONG PREFRONTAL TROUGH/WARM FRONT. ABOVE BOUNDARY CLOSE TO EXITING FA
TO THE EAST AND NOW CONFINED TO HUBBARD/BELTRAMI COUNTY. TRIMMED
BACK ON POPS THIS AREA. FARTHER NORTHWEST MORE ROBUST BUT WIDELY
SCATTERED CONVECTION CONTINUES ALONG INTERNATIONAL BORDER AREA
ASSOCIATED WITH SECONDARY BOUNDARY AND MID LEVEL WAVE RIDING ALONG
INTERNATIONAL BORDER. HAVE HIGHEST POPS ALONG INTERNATIONAL BORDER
INTO EARLY AM AS FEATURE CONTINUES TO PROPAGATE EAST IN
MODERATELY UNSTABLE AIR MASS. ELSEWHERE ADJUSTED POPS ACCORDINGLY
BASED ON CURRENT RADAR TRENDS. REMAINDER OF FORECAST UNCHANGED FOR
THIS UPDATE.
UPDATE ISSUED AT 645 PM CDT THU JUL 18 2013
DEEP CONVECTION BECOMING A LITTLE BETTER ORGANIZED ALONG FRONTAL
BOUNDARY FROM NEAR FSE NE TO INL. SO FAR CELLS HAVE REMAINED BLO
SVR LIMITS HOWEVER WILL CONTINUE TO MONITOR. FARTHER NW ISOLD
SHRA/TSRA CLOSING IN ON FAR NW FA HOWEVER STRONGER STORMS STILL
WELL NORTH OF INL BORDER AND CONFIDENCE NOT VERY HIGH ON SEVERE
POTENTIAL THIS AREA. FOR NOW WITH STRENGTH OF MID LEVEL IMPULSE
AND DEGREE OF INSTABILITY CANNOT RULE OUT ISLD STRONG STORM SO
WILL MAINTAIN STRONGER STORM WORDING THIS AREA. MADE SOME MINOR
POP ADJUSTMENTS THROUGH MID EVENING TRYING TO FINE TUNE AREAS FOR
BEST STORM POTENTIAL ACROSS N CENTRAL MN. PULLED POPS ACROSS
CENTRAL FA IN BETWEEN BOUNDARIES WHERE CONVECTION NOT ANTICIPATED.
TEMPERATURES STILL WARM/HUMID BUT BLO HEAT ADVISORY CRITERIA SO WILL
ALLOW TO EXPIRE ON TIME. ANY OTHER CHANGES MINIMAL THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 250 PM CDT THU JUL 18 2013
SEVERE POTENTIAL THIS EVENING WILL BE THE MAIN CONCERN. HEAT
ADVISORY CONDITIONS ACROSS THE SOUTHERN FA WILL CONTINUE INTO THE
EARLY EVENING HOURS. THE MAIN SEVERE RISK AREA WILL BE ALONG THE
WARM FRONT FROM JUST EAST OF GRAND FORKS INTO BEMIDJI...AND
LOCATIONS 50 MILES NORTH AND SOUTH OF THIS LINE. SPC SUPERCELL
COMPOSITE AND SIGNIFICANT TORNADO PARAMETERS INDICATE THIS AREA
WITH THE GREATEST POTENTIAL. 19Z LAPS ANALYSIS STILL INDICATES A
STRONG CAP (MLCIN AOA 40 J/KG)...AND NOT SURE HOW WIDESPREAD
INITIATION WILL BE. HRRR HAS BEEN CONSISTENT WITH DEVELOPING
STORMS...AND WILL CONTINUE TO FOLLOW ITS COVERAGE AND INITIATION
TIMES. ANTICIPATE SUPERCELL STORMS CAPABLE OF ALL MODES OF SEVERE
WEATHER. THERE IS ANOTHER AREA OF CONCERN ACROSS THE NW FA AS THE
UPPER WAVE APPROACHES THIS EVENING. AN AREA OF STORMS HAS
DEVELOPED WELL TO THE NW IN SASKATCHEWAN (JUST AHEAD OF THE UPPER
WAVE)...AND INSTABILITY SHOULD INCREASE JUST AHEAD OF THIS
COMPLEX. THIS COMPLEX MAY STILL BE SEVERE AS IT MOVES INTO THE NW
FA...AND QUICKLY WEAKEN BY MIDNIGHT.
FRIDAY-FRIDAY NIGHT...ANOTHER COLD FRONT WILL MOVE INTO THE REGION
ON FRIDAY. INSTABILITY WILL BE WEAK...BUT SHOULD BE ENOUGH FOR
ISOLD SHOWERS AND POSSIBLY THUNDER FRIDAY AFTERNOON. SFC HIGH
PRESSURE WILL BEGIN WORKING INTO THE REGION FROM THE NE FRIDAY
NIGHT...AND MIN TEMPS BY SATURDAY MORNING SHOULD BE INTO THE 40S
ACROSS NE MN (WARMER TO THE WEST AND SOUTH).
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
SATURDAY-SUNDAY...MODELS AGREE WITH NORTHWEST FLOW ALOFT AND
SURFACE RIDGING ACROSS MUCH OF THE FA. THE SURFACE RIDGE GRADUALLY
SHIFTS BACK TO THE EAST BY SUNDAY. THUNDER CHANCES WILL BE ON THE
WESTERN EDGE OF THE FA ON SATURDAY...AND SHIFT TO THE EAST BY
SUNDAY. FORCING AND INSTABILITY WILL BE WEAK...SO EXPECT ONLY
ISOLD TO SCATTERED ACTIVITY. TEMPERATURES WILL BE BELOW NORMAL
VALUES AS A RELATIVELY COLDER AIRMASS WILL BE ACROSS THE REGION.
SUNDAY NIGHT-THURSDAY...LONG TERM MODELS ARE IN POOR AGREEMENT.
IN GENERAL...ECMWF TRACK OF SFC LOWS TRANSITING SOUTHERN CANADA
NEXT WEEK ARE MUCH FURTHER NORTH THAN THE GFS...WHICH BRINGS THEM
ACROSS NORTHERN TIER OF CONUS. ECMWF ALSO CONTINUES TO PRODUCE A
LOT OF QPF...WHICH SEEMS UNREALISTIC. THEY DO AGREE SOMEWHAT ON A
NW FLOW UPPER AIR PATTERN BUT EVEN THAT DIVERGES BY DAY 6. THUS
LOW POPS IN CONSALL IS A RESULT OF ECMWF BLENDED INTO THE
SOLUTION. CONFIDENCE IS LOW BEYOND DAY 4 (NIGHT). BEST CHANCE
APPEARS TO BE SUN NIGHT INTO MON MORNING...WHEN AN UPPER WAVE
MOVES ACROSS THE AREA. BEST CHANCES WILL BE ACROSS THE NORTHEAST
AND DO HAVE A FAIR DEGREE OF CONFIDENCE FOR 40S POPS ACROSS THE
NORTH. GFS WOULD THEN GIVE US DRY WEATHER MON NIGHT AND I HAVE
REMOVED CHANCE POPS FOR THIS PERIOD. GFS THEN BRINGS ANOTHER SFC
LOW INTO NORTHERN TIER TUE NIGHT...FOR ANOTHER CHANCE OF
SHOWERS/TSTMS ACROSS THE NORTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1132 PM CDT THU JUL 18 2013
ISOLATED TSRA WILL CONTINUE ALONG AND NORTH OF A LINE FROM TVF TO BJI
FOR A FEW MORE HOURS HOWEVER CIGS/VSBY TO REMAIN VFR. REMAINDER OF
FA WILL REMAIN VFR THROUGH THE FORECAST PERIOD. CONFIDENCE NOT
HIGH ENOUGH TO ADD PCPN MENTION TOMORROW AFTERNOON AHEAD OF NEXT
COLD FRONT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1049 PM MDT THU JUL 18 2013
.UPDATE...
ISSUED AT 821 PM MDT THU JUL 18 2013
02Z SURFACE ANALYSIS SHOWED COOL FRONT/TROUGH EXITING CWA. DIURNAL
CYCLE TAKING IT/S TOLL ON TSRA WITH ACTIVITY ABOUT DONE SAVE FOR
SOME ANVIL DEBRIS. LOOKS PRETTY QUITE OVERNIGHT PER 00Z RAP AND
00Z KUNR SOUNDING. WILL LEAVE SMALL POPS NEAR THE NE BORDER GIVEN
NUMEROUS BOUNDARIES AND PROXIMITY TO 850-700MB FRONT AND ELEVATED
INSTABILITY.
&&
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 221 PM MDT THU JUL 18 2013
NORTHERN STREAM IMPULSE CONTINUES TO ADVECT/PROPAGATE
TO THE EAST ACROSS SOUTHERN SK/MB WITH AN ORPHANING TROUGH AXIS OVER
THE SOUTHERN FA. MOISTURE POOLING JUST BEHIND THE TROUGH COUPLED
WITH DIURNAL HEATING/SOUTHERN BH CONVERGENCE/AND WEAK LSA HAS
SUPPORTED A CLUSTER OF THUNDERSTORMS OVER THE SOUTHERN BH...WITH
ADDITIONAL CELLS EXPECTED TO INITIATE ACROSS THE EASTERN AND
SOUTHERN FA THIS AFTERNOON AND EVENING...AS THE TROUGH PROGRESSES SE
AND INHIBITION WEAKENS PER DIURNAL HEATING. CELLS WILL CONTINUE TO
FIGHT THE CAPPING INVERSION ACROSS THE EASTERN AND SE FA WITH FAIRLY
WARM TEMPS ALOFT HIGHLY LIMITING CAPE. MARGINAL TO WEAK DEEP LAYER
SHEAR SHOULD PREVENT MOST STORMS FROM ORGANIZATION...REMAINING PULSE
DRIVEN. WIDESPREAD MASSIVE CONUS RIDGE WILL EVENTUALLY FLATTEN AS A
STRONGER MORE PRONOUNCED UPPER SHORTWAVE DIGS SE INTO THE GREAT
LAKES THROUGH FRIDAY. MEANWHILE...LOCAL DEEP LAYER FLOW WILL TURN
NW...WITH IMPULSES ORIGINATING FROM THE CLOSED NE PAC UPPER LOW
EXPECTED IN THE FLOW. AFOREMENTIONED TROUGH AND ASSOCIATED LL
MOISTURE BUBBLE WITH THETA-E POOLING WILL RESIDE OVERT THE SW FA
THROUGH FRIDAY NIGHT. FORECAST MODELS ARE IN RATHER STRONG AGREEMENT
THAT A WEAK...BUT SUFFICIENT IMPULSE WILL PASS THROUGH THE FLOW FRI
NIGHT...WITH REFLECTED FRONT SIDE SOUTHERLY FLOW /INDICATED WELL AT
H7/ EXPECTED TO SUPPORT A PERIOD OF POS THETA-E ADV UNDER FAIRLY
STEEP MID LEVEL LAPSE RATES. GIVEN AMPLE LL SLIGHTLY ELEVATED
MOISTURE IN PLACE...SHOWER AND THUNDERSTORMS CHANCES LOOK GOOD OVER
THE REGION...WITH THE POSSIBLY OF A SMALL MCS. THERE IS A SMALL
POTENTIAL FOR A SEVERE STORM OR TWO FRI NIGHT. PROGGED DEEP LAYER
SHEAR UTILIZING AN ELEVATED PARCEL SUGGEST 30 TO 45 KNOTS OF BULK
SHEAR...WITH MU CAPE AOA 1000 J/KG ACROSS THE FAR SW FA PER NAM
DATA. THIS WILL HAVE TO WATCHED.
RETAINED LOW CHANCE POPS ACROSS THE SE FA THROUGH THIS
EVENING...WITH LOW SLIGHTS ACROSS THE FAR SW LATE TONIGHT FOR
POSSIBLE ELEVATED SHOWERS...WHICH MAY END UP AS JUST VIRGA. ALSO
RETAINED LOW SLIGHTS ACROSS THE SW FA FRI GIVEN THE COLLOCATION OF
THE LL THETA-E PLUME. HOWEVER...MODEL DATA SUGGEST THAT THIS PLUME
OF MOISTURE WILL REMAIN ELEVATED. HENCE...ANY MODEL GENERATED QPF IN
THIS PERIOD MAY BE FROM AN ACCAS PLUME. DID TREND POPS UP ACROSS THE
SW HALF FRIDAY NIGHT GIVEN ABOVE CONCERNS.
AS FOR TEMPS...WARM TO HOT CONDITIONS CAN BE EXPECTED MOST PLACES
FRIDAY...ALTHOUGH 5 TO 10 DEGREES COOLER THAN TODAY/S TEMPS AS THE
THERMAL RIDGE SHIFTS EAST. LOWS GENERALLY IN THE 60S CAN BE
EXPECTED BOTH TONIGHT AND FRIDAY NIGHT.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 221 PM MDT THU JUL 18 2013
BROAD...RELATIVELY FLAT LONG WAVE RIDGE HAS
RETROGRESSED TO ABOUT 105W WITH NEXT UPSTREAM TROF NEAR 130W. RIDGE
IS FCST BY BOTH GFS AND ECMWF MODELS TO CONTINUE MOVING W WARD TO
NEAR THE PAC COAST BY 12Z SATURDAY AND TO NEAR 130W BY 12Z SUNDAY.
THE TREND IS THEN FOR IT TO MOVE SLOWLY E WARD AND AMPLIFY A BIT BY
12Z WED. THIS PLACES WEAK WNW FLOW OVER OUR CWA DURING ALL OF THE
LONG TERM PERIOD. SEVERAL WEAK SHORT WAVES WILL MOVE ACROSS THE AREA
IN THIS FLOW. TIMING OF THESE WAVES IS HANDLED VERY DIFFERENTLY BY
EACH OF THE MODELS...SO HAVE NOT TRIED TO PIN THEM DOWN TOO CLOSELY
IN POPS.
STAYED CLOSE TO GUIDANCE IN TEMPS WITH LITTLE REASON TO DEPART.
AS NOTED BY PREVIOUS SHIFT...EXTENDED GRID INITIALIZATION PLACED DEW
POINTS THE LOOK TOO HIGH OVER OUR WY COUNTIES. THE INITIALIZATION IS
NOT HANDLING DIURNAL DEW POINT TRENDS WELL...SO MOST NIGHT TIME DEW
POINTS WERE LOWERED CLOSER TO GFS AND EURO MOS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1045 PM MDT THU JUL 18 2013
ISOLATED TSRA ARE POSSIBLE FOR THE REST OF TONIGHT NEAR THE NE
BORDER. AFTER A QUIET MORNING...ADDITIONAL TSRA WILL DEVELOP OVER
WY FRIDAY AFTERNOON...SPREADING EAST/NORTH ACROSS SD LATER FRIDAY
AFTERNOON/NIGHT. VFR CONDITIONS WILL PREVAIL OUTSIDE OF
TSRA...EXCEPT FOR LOCAL MVFR CIGS/VSBYS IN/NEAR STORMS.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...BARBER
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1155 PM CDT THU JUL 18 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
NOT MUCH CHANGE FROM THE PREVIOUS DISCUSSION AT 00Z. VFR
CONDITIONS EXPECTED FOR MOST LOCATIONS FROM KCXO SOUTH TO THE
COAST...WITH THE EXCEPTION AT KUTS TOWARD SUNRISE. ANY SHOWERS OR
THUNDERSTORMS THAT DO DEVELOP SHOULD DISSIPATE BY EARLY FRIDAY
EVENING.
40
&&
.PREV DISCUSSION... /ISSUED 858 PM CDT THU JUL 18 2013/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
A VARIETY OF CONDITIONS ACROSS SE TX THIS EVENING. SFC DEW POINTS
VARY WILDLY ACROSS THE AREA WITH MID 50S OVER THE EXTREME NW
ZONES...MID TO UPPER 60S CENTRAL AND LOWER TO MID 70S ALONG THE
COAST AND OVER THE NORTHEAST. CONVECTION OVER THE CWA HAS WANED
AND THE STORMS TO THE EAST ALSO SHOWS SIGNS OF WEAKENING. THE
LATEST RAP SUPPORTS OTHER SHORT TERM MODELS WITH CONVECTION
GENERALLY ENDING WITH POSSIBLE REDEVELOPMENT ALONG THE COAST PRIOR
TO SUNRISE. 00Z SOUNDINGS SHOW PW VALUES NEAR 1.9 INCHES AND 1.7
INCHES AT CRP. 850 MB MOISTURE WAS HIGHER OVER LOUISIANA AND DRIER
TOWARD THE MIDDLE AND LOWER TEXAS COAST. A WEAK 850 MB LOW WAS
LOCATED OVER EASTERN LOUISIANA WITH A WEAKNESS ALOFT ALSO OVER
EASTERN LA. THIS WEAKNESS IS PROGGED TO SHIFT WEST ON FRIDAY AND
WILL PROBABLY BRING THE EASTERN HALF OF THE AREA SLIGHTLY HIGHER
RAIN CHANCES. WILL ISSUE NEW ZONES TO CLEAN UP EVENING WORDING
ONCE THE THREAT FOR CONVECTION ENDS. 43
PREV DISCUSSION... /ISSUED 647 PM CDT THU JUL 18 2013/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
40
AVIATION...
THE MAIN WEATHER FEATURES AFFECTING SE TX AT 2330Z THIS EVENING
WERE THE SURFACE HIGH PRESSURE RIDGE EXTENDING INTO THE AREA FROM
KY AND WHAT LOOKED TO BE A TUTT LOW INLAND OF THE FL AND AL
COASTS. THE DRY MID AND UPPER LEVEL AIRMASS THAT WAS OVER THE AREA
EARLIER TODAY WAS PUSHING OFF TO THE SOUTHWEST. ISOLATED SHOWERS
WILL LIKELY AFFECT AT LEAST KUTS AND KCLL THROUGH ABOUT 02Z OR SO.
THESE MAY DEVELOP A BIT FURTHER TO THE SOUTH AND WILL AMEND IF
NECESSARY. OTHER STORMS OVER WESTERN LA SHOULD DISSIPATE AFTER
SUNSET.
ALTHOUGH THERE MAY BE ANOTHER ISOLATED EPISODE OF A SITE
EXPERIENCING IFR OR LOWER LATE TONIGHT OR EARLY FRIDAY MORNING...
EXPECT MOST LOCATIONS TO REMAIN VFR THROUGH THE NIGHT AND ON
FRIDAY. WENT WITH MVFR FOR KUTS AND KCXO BUT THESE CONDITIONS
COULD ALSO AFFECT KLBX AS WELL. FOR THE MOST PART...FELT THAT AS
THE UPPER LOW MOVES WESTWARD THAT SE TX SHOULD BE IN THE
RELATIVELY DRIER SIDE OF THE SYSTEM THROUGH MIDDAY. THE EXCEPTIONS
SHOULD BE THOSE LOCATIONS NEAR AND ALONG THE COAST IF ISOLATED
SHOWERS DEVELOP OFF THE COAST AND MOVE INLAND DURING THE MORNING.
THE NAM12 WAS MORE AGGRESSIVE TOMORROW AFTERNOON AND FELT THAT
THE CHANCES WERE HIGH ENOUGH GIVEN THAT ANY MOISTURE WRAPPING
AROUND THE UPPER LOW SHOULD HELP ENHANCE THE SEABREEZE OR THE LIFT
PROVIDED BY THE UPPER LEVEL SYSTEM. FOR NOW WILL END THE RAIN
CHANCES NEAR THE COAST AND GO WITH A VCSH DURING THE LATTER HALF
OF THE AFTERNOON FOR MOST INLAND SITES NEAR THE METRO HOUSTON
AIRPORTS.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 93 72 94 73 / 20 20 20 30 10
HOUSTON (IAH) 75 93 73 93 73 / 20 30 20 30 20
GALVESTON (GLS) 79 90 79 89 78 / 20 30 20 30 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT FRI JUL 19 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE WESTERN U.S. AS WELL AS OVER THE
MID-ATLANTIC...WHILE TROUGHING WAS IN-BETWEEN FROM SOUTH CENTRAL
CANADA INTO WESTERN MN. THIS TROUGHING IS COMPOSED OF A POTENT
SHORTWAVE OVER MANITOBA...A SHORTWAVE FROM CENTRAL NORTH DAKOTA INTO
NORTHERN MN...AND A DEEP DRY-SLOT AHEAD OF THE SHORTWAVE FROM SOUTH
DAKOTA INTO WESTERN LAKE SUPERIOR. A COLD FRONT AT THE SURFACE WAS
ANALYZED FROM NEAR SIOUX FALLS TO THUNDER BAY ONTARIO...SLIGHTLY
AHEAD OF THE DRY SLOT. AMAZINGLY...DESPITE 4000 J/KG OF SBCAPE AND
LITTLE CIN ON THE 00Z ABR SOUNDING...THE FRONT WENT THROUGH THERE
WITH LITTLE ACTIVITY. BEST GUESS WAS THE LACK OF CONVERGENCE ON THE
FRONT...WHICH WAS REPRESENTED WELL ON 0-2KM RAP CONVERGENCE PLOTS.
FRONT IS MORE ACTIVE NOW...MORESO THE WARM ADVECTION AHEAD OF
IT...WITH HIGHER BASED SHOWERS AND THUNDERSTORMS FROM FARMINGTON MN
TO PARK FALLS WI. WARM AIR CONTINUES TO HOLD STRONG IN THE WARM
SECTOR WITH READINGS IN THE UPPER 70S / LOW 80S...THANKS IN PART TO
A 30-45 KT 925MB WINDS OVER THE AREA. THERE IS EVEN WARMER AIR
FLOWING IN FROM THE WEST ALONG THE FRONT...OBSERVED ON THE 00Z ABR
SOUNDING WITH AN 800MB TEMP OF 20C AND 925MB TEMP OF 30C...COMPARED
TO 17C AND 27C RESPECTIVELY FROM THE 00Z MPX SOUNDING. BEHIND THE
FRONT...925MB TEMPS ARE NOT THAT MUCH COOLER WITH 28C OBSERVED AT
GGW...BUT DEWPOINTS DROP INTO THE 50S AND LOW 60S.
SYNOPTIC OVERVIEW...
UPPER TROUGHING IS STILL POISED TO FORM OVER THE WESTERN GREAT LAKES
REGION BY 06Z TONIGHT...THOUGH THE MORE POTENT SHORTWAVE COMPOSING
THE TROUGH IS FORECAST TO STAY UP IN CANADA. MEANWHILE...THE
SHORTWAVE SEEN UP IN CENTRAL NORTH DAKOTA IS SLATED TO DROP INTO
CENTRAL MN BY 18Z...THEN PUSH EAST INTO LOWER MI. WITH THE UPPER
TROUGHING FORMING...EXPECT THE COLD FRONT TO CONTINUE MARCHING
SOUTHEAST. MODEL TIMING IS WELL AGREED UPON...AT 18Z STRETCHING FROM
OMAHA NEB TO VOLK FIELD WI AND MARINETTE WI...AND AT 00Z FROM
NORTHWEST MO TO NEAR DUBUQUE IA AND UP TO MANITOWOC WI.
HAZARDS...
ONGOING HEAT ADVISORY...DUE TO FRONTAL TIMING AND DRYING DEWPOINTS
BEHIND THE FRONT...HAVE CANCELLED SOME OF THE ADVISORY. AREAS
INCLUDE SOUTHEAST MN AND PORTIONS OF NORTHEAST IOWA INTO CENTRAL WI.
THERE ALSO IS A CHANCE FOR SEVERE WEATHER THIS AFTERNOON ALONG THE
COLD FRONT COMING THROUGH NORTHEAST IOWA AND SOUTHWEST WI. 0-6KM
SHEAR VALUES ARE HIGHER IN THE 09.00Z NAM...ORDER OF 30-40 KT VERSUS
20-30 KT IN THE 09.06Z RAP. IF SEVERE WEATHER OCCURS...DAMAGING
WINDS WOULD BE THE MAIN HAZARDS.
TODAY...
TWO BIG QUESTIONS...TEMPERATURES AND PRECIPITATION CHANCES. ON THE
PRECIPITATION SIDE OF THINGS...19.00Z GFS/NAM/REGIONAL CANADIAN ALL
WANT TO BRING THE SHOWERS AND SOME THUNDERSTORMS THROUGH THE
FORECAST AREA THIS MORNING PRIOR TO THE FRONTAL PASSAGE. THESE
ORIGINATE FROM ISENTROPIC LIFT ON THE 310 K SURFACE AHEAD OF THE
FRONT. IT APPEARS THESE SHOULD WEAKEN THROUGH THE MORNING TOO WITH
THE NOCTURNAL LOW LEVEL JET WEAKENING. A PERIOD OF CLEARING THEN
TAKES PLACE IN THE WARM SECTOR...WITH SOME HINTS FROM THE 19.00Z
GFS/REGIONAL CANADIAN AND 19.06Z RAP THAT THE FRONT COULD CONVECT IN
SOUTHEASTERN PORTION OF THE FORECAST AREA SAY BETWEEN 19-23Z. NOT
THRILLED ABOUT THE FRONT CONVECTING AS THE 0-2KM CONVERGENCE IS VERY
WEAK. HOWEVER...GIVEN MODELS HAVE BEEN SHOWING IT THE PAST FEW DAYS
AND PLENTY OF INSTABILITY PROGGED TO DEVELOP TODAY...KEPT SOME
CHANCES IN THE FORECAST. HAVE ALSO ADDED SOME LOW CHANCES OF
PRECIPITATION FOR THE AFTERNOON HOURS FROM TAYLOR COUNTY SOUTH TO
JACKSON. HERE ANOTHER FRONT LURKING UP IN NORTHERN MN IS PROGGED BY
THE 09.06Z RAP AND 09.05Z HRRR TO COME THROUGH AND HAVE SOME
CONVECTION ON IT. ON THE TEMPERATURE SIDE OF THINGS...A WARM START
PLUS 925MB TEMPS HOLDING IN THE 24-26C RANGE SHOULD EASILY ALLOWS
HIGHS TO REACH THE UPPER 80S TO POSSIBLY MID 90S AGAIN. THIS IS EVEN
DESPITE THE FRONTAL PASSAGE GIVEN THE WARM AIR STILL HOLDING BACK
AND LIKELY DEEPER MIXING BEHIND THE FRONT. HOWEVER...HEAT INDICES
WILL FALL WITH THE FRONT AS DRIER DEWPOINTS FLOW IN.
TONIGHT...
SUBSIDENCE AND DRYING COMING IN BEHIND THE COLD FRONT WILL ALLOW FOR
A MOSTLY CLEAR NIGHT ACROSS THE FORECAST AREA. DRIER AIR AND
DIMINISHING WINDS SHOULD ALLOW TEMPERATURES TO FALL CLOSE TO
GUIDANCE VALUES...IN THE UPPER 50S TO MID 60S...10-15 DEGREES COLDER
THAN TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM CDT FRI JUL 19 2013
SYNOPTIC OVERVIEW...
MUCH OF THE NEXT 6 DAYS LOOKS TO BE DOMINATED BY NORTHWEST FLOW
ACCORDING TO THE 19.00Z ECMWF/GFS/CANADIAN WITH RIDGING STAYING PUT
OVER THE WESTERN U.S.. THERE ARE SOME SIGNS FROM THE ECMWF THE RIDGE
MAY WANT TO BUILD EAST TOWARDS THE FORECAST AREA ON THURSDAY...BUT
PLENTY OF UNCERTAINTY ON THAT SEEING THE TROUGHING IN THE GFS.
ADDITIONALLY...THIS NORTHWEST FLOW HAS UNCERTAINTY IN TERMS OF
TIMING SHORTWAVES AND THE CHANCES OF PRECIPITATION WITH THEM.
SATURDAY THROUGH SUNDAY NIGHT...
MAIN FEATURE OF INTEREST DURING THIS PERIOD IS A SHORTWAVE ALL
MODELS HAVE TRACKING OUT OF MONTANA ON SATURDAY AND THROUGH THE
FORECAST AREA ON SUNDAY. SURPRISINGLY MODELS ARE IN REALLY GOOD
AGREEMENT WITH THIS SHORTWAVE...ALBEIT PERHAPS THE GFS HAS A BIT OF
CONVECTIVE FEEDBACK TO IT. IN ANY EVENT...INCREASING 310 K
ISENTROPIC LIFT COMBINED WITH INSTABILITY SHOULD INITIATE CONVECTION
OVER EASTERN SOUTH DAKOTA DURING THE AFTERNOON. THIS CONVECTION THEN
SPREADS TOWARDS THE FORECAST AREA SATURDAY NIGHT AS THE ISENTROPIC
LIFT AND 850MB MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE SHIFTS
EAST. PERHAPS THERE IS A SHOT SOME HIGH BASED SHOWERS COULD DEVELOP
DOWNSTREAM OF THE CONVECTION SATURDAY AFTERNOON...BUT THINK THE BULK
OF THE PRECIPITATION WOULD WAIT UNTIL SATURDAY NIGHT. SUNDAY APPEARS
TO HAVE THE HIGHEST CHANCE OF RAIN WHERE DPVA ACCOMPANYING THE
SHORTWAVE INTERSECTS 850MB MOISTURE TRANSPORT CONTINUING TO AIM AT
THE AREA. ITS HARD TO SAY HOW SUNDAY NIGHT WILL EVOLVE. SUBSIDENCE
BEHIND THE SHORTWAVE MOVING THROUGH ON SUNDAY WOULD SEEM TO LIKELY
PROVIDE A DRY PERIOD...LIKE SUGGESTED BY THE 19.00Z NAM. HOWEVER...
THE 19.00Z GFS/ECMWF SHOW A POTENT SHORTWAVE TROUGH CROSSING
SOUTHERN MANITOBA SUNDAY NIGHT...WHICH INCREASES 850MB MOISTURE
TRANSPORT INTO THE AREA. THEREFORE...THESE MODELS WANT TO HANG ONTO
SOME SHOWERS. HAVE MAINTAINED SOME CHANCES OF PRECIPITATION TO
ACCOUNT FOR THE GFS/ECMWF SCENARIO. BIGGEST ISSUE IN THE TEMPERATURE
DEPARTMENT IS HIGHS ON SUNDAY. IF IT RAINS ALL DAY...TEMPERATURES
MAY GET STUCK IN THE UPPER 60S/LOW 70S. FOR NOW TRENDED HIGHS DOWN
SLIGHTLY.
MONDAY THROUGH THURSDAY NIGHT...
THIS PERIOD IS HIGHLY UNCERTAIN. 19.00Z GFS/ECMWF/CANADIAN SHOW
NUMEROUS SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT THROUGH
MUCH OF THE WEEK. TIMING AND TRACK OF THESE VARIES FROM RUN TO
RUN...THUS THE LOW CONFIDENCE. THERE DOES APPEAR TO BE SOME SIGNAL
FOR A COLD FRONT COMING THROUGH THE FORECAST AREA MONDAY
NIGHT...ASSOCIATED WITH THAT POTENT TROUGH OVER SOUTHERN MANITOBA
PROGGED TO LIFT EAST-NORTHEAST. IF THIS STAYS CONSISENT...WE MIGHT
BE ABLE TO DRY OUT TUESDAY. OTHERWISE...HAVE MAINTAINED A MODEL
CONSENSUS OF 20-40 PERCENT CHANCES THROUGH THURSDAY NIGHT. LIKELY
THE ENTIRE PERIOD WILL NOT BE WET...BUT HARD TO PIN POINT MUCH FOR
POSSIBLE DRY PERIODS BEYOND TUESDAY. WITH A NORTHWEST FLOW IN
PLACE...EXPECT A COOLER FLOW OF AIR. 850MB TEMPS ARE GENERALLY
PROGGED TO DROP FROM 18-20C ON MONDAY TO 12-15C FOR TUESDAY THROUGH
THURSDAY. THESE SHOULD RESULT IN A DROP IN HIGHS TO SLIGHTLY BELOW
NORMAL AFTER NEAR NORMAL ON MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1111 PM CDT THU JUL 18 2013
A COLD FRONT WILL SWEEP SOUTHEAST ACROSS THE REGION EARLY ON FRIDAY
MORNING...LIKELY AROUND THE 15Z TIME FRAME FOR KRST/KLSE...GIVE OR
TAKE AN HOUR. MOISTURE FIELDS AND BUFKIT SOUNDINGS SUGGEST MOSTLY
MID LEVEL/VFR CLOUDS WITH THE FRONT AS IT MOVES THROUGH...SCATTERING
OUT AS IT PASSES. SHOULD BE ENOUGH INSTABILTY AND LIFT IN THE
VICINITY OF THE FRONT FOR SCATTERED SHRA/TS. WHETHER THEY WILL
IMPACT KRST/KLSE IS STILL NOT CLEAR...SOME PCPN SHOULD BE IN THE
AREA. WILL GO WITH A MIX OF -SHRA/VCSH FOR NOW...LEAVING OUT A
MENTION OF TS AND ANY VSBY RESTRICTIONS FOR NOW. THIS WILL BE
ADJUSTED AS NEEDED BASED ON RADAR/MESO MODEL TRENDS.
FOR WINDS...SOUTH-SOUTHWEST WILL SWING TO THE NORTHWEST WITH THE
PASSAGE OF THE FRONT. BUFKIT SOUNDINGS CONTINUE TO SUGGEST LLWS WILL
BE A CONCERN...WITH NEAR 50 KTS OF WIND BY 2 KFT FOR A FEW HOURS AT
KRST AND AROUND 45 KTS AT KLSE OVERNIGHT. WILL CONTINUE LLWS MENTION
IN THE TAFS.
&&
.CLIMATE...
ISSUED AT 321 AM CDT FRI JUL 19 2013
LA CROSSE WI HAS ONLY SEEN 0.27 INCHES FOR THE MONTH OF JULY
THROUGH THE 18TH. THIS IS THE 5TH DRIEST START TO JULY. THE DRIEST
THROUGH JULY 18TH WAS 0.05 INCHES BACK IN 1896...AND THE LAST TIME
IT WAS THIS DRY WAS IN 1967. FOR REFERENCE...LA CROSSE NORMALLY
SHOULD HAVE 2.41 INCHES UP THROUGH THE 18TH.
ROCHESTER MN HAS HAD QUITE A BIT MORE RAIN...THUS THE 1.42 INCHES
OBSERVED THROUGH JULY 18TH IS WELL OUTSIDE THE TOP 20 DRIEST.
STILL ROCHESTER IS 1.25 INCHES BELOW NORMAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...NONE.
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ011-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
945 AM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 945 AM EDT FRI JUL 19 2013
FOG PERSISTED IN THE UPPER REACHES OF THE CUMBERLAND VALLEY AT MID
MORNING...BUT HAD DISSIPATED ELSEWHERE...AND SHOULD SOON BE GONE
EVERYWHERE. OUTSIDE OF FOG...SKIES WERE GENERALLY CLEAR AT MID
MORNING. HAVE DELAYED THE INCREASE IN CLOUD COVER AND PRECIP TODAY...
WITH WIDESPREAD CU DEVELOPMENT EXPECTED AROUND MID DAY...AND
SCATTERED SHOWERS AND THUNDERSTORMS TO SOON FOLLOW.
UPDATE ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGETOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEW POINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PRE-FIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEW POINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 750 AM EDT FRI JUL 19 2013
FOG WILL CONTINUE TO LIFT AND DISSIPATE THROUGH ABOUT 13Z. INITIALLY
FOG WILL BE BELOW AIRPORT MINS AT JKL AND IN THE IFR RANGE AT
LOZ...WITH THIS IMPROVING BY 13Z. DIURNALLY DRIVEN CONVECTION
SHOULD DEVELOP AFTER 16Z...BUT DECREASE IN COVERAGE BY THE 0Z TO 3Z
PERIOD. SOME MVFR OR LOWER FOG WILL BE POSSIBLE IN ALL AREAS FROM
ABOUT 6Z ON ONCE AGAIN...ESPECIALLY WHERE CONVECTION OCCURS LATER
TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...AR
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGETOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEWPOINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PREFIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEWPOINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 750 AM EDT FRI JUL 19 2013
FOG WILL CONTINUE TO LIFT AND DISSIPATE THROUGH ABOUT 13Z. INITIALLY
FOG WILL BE BELOW AIRPORT MINS AT JKL AND IN THE IFR RANGE AT
LOZ...WITH THIS IMPROVING BY 13Z. DIURNALLY DRIVEN CONVECTION
SHOULD DEVELOP AFTER 16Z...BUT DECREASE IN COVERAGE BY THE 0Z TO 3Z
PERIOD. SOME MVFR OR LOWER FOG WILL BE POSSIBLE IN ALL AREAS FROM
ABOUT 6Z ON ONCE AGAIN...ESPECIALLY WHERE CONVECTION OCCURS LATER
TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...AR
AVIATION...JP
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
655 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM CDT FRI JUL 19 2013
OUR MPX WRF AND HOP WRF ARE ON SIMILAR PATHS WITH THE SHOWER AND
THUNDERSTORM ACTIVITY EXITING OUR AREA BY 12Z. FOR TODAY...A BREAK
FROM THE HEAT AND HUMIDITY WILL BE NOTED WITH SOME SCATTERED
CLOUDS...EXCEPT FOR SOUTHWEST MN WHICH MAY BE CLOUD FREE. VERY DRY
AIR ABOVE 6000 FEET WILL CONTINUE WORKING ITS ITS WAY INTO WESTERN
MN. THERE IS SOME LOW LEVEL MOISTURE ACROSS EASTERN MN AND WESTERN
WI. THE RAP KEEPS THIS MOISTURE IN PLACE UNTIL MID AFTERNOON. SHOULD
BE PLENTY OF MIXING SO DO NOT EXPECT MORE THAN SCATTERED
CLOUDS...EXCEPT SW MN WHERE IT MAY BE CLEAR. MAY BE CLEAR AFTER 21Z
IN MOST AREAS AS DRIER AIR FILTERS IN. OVERNIGHT A SECONDARY COLD
FRONT USHERS IN COOLER AIR AND BY SATURDAY MORNING A DISTURBANCE
MOVES TOWARD WESTERN MN WITH AN INCREASE IN MOISTURE. NO
PRECIPITATION EXPECTED THROUGH 12Z SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM CDT FRI JUL 19 2013
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE RIDGING OVER THE
ROCKIES...WITH EPISODIC IMPULSES PARADING ACROSS THE NORTHERN CONUS.
THE FIRST OF THESE SHORTWAVES HAS BEEN CONSISTENTLY PROGGED TO
ARRIVE ON SATURDAY NIGHT INTO SUNDAY BY DETERMINISTIC AND ENSEMBLE
SOLUTIONS. FAIRLY IMPRESSIVE LIFT FROM 305-310K IS PROGGED TO
BLOSSOM OVER THE AREA BETWEEN 06Z AND 12Z SUNDAY AS 925-850 MOISTURE
TRANSPORT NOSES INTO SOUTHERN MN. HAVE INCLUDED 50-60 POPS FOR THIS
TIME FRAME.
NORTHWEST FLOW PERSISTS THROUGH THE BEGINNING OF NEXT WEEK...WHICH WILL
NECESSITATE THE INCLUSION OF 20-30 POPS FOR A LONG DURATION. THE
TUESDAY INTO WEDNESDAY TIME FRAME IS TRENDING DRIER HOWEVER...AS
DRY SURFACE HIGH PRESSURE BUILDS IN...SO MAY BE ABLE TO SHED
SHOWER AND THUNDERSTORM CHANCES FOR THOSE DAYS.
WEDNESDAY NIGHT INTO FRIDAY LOOK WET AGAIN HOWEVER....AS SHORTWAVE
ENERGY CHANNELS THROUGH THE WESTERN PERIPHERY OF THE ONTARIO LOW.
TEMPERATURES WILL REMAIN RELATIVELY STATIC THROUGH THE EXTENDED
PERIOD...WITH HIGHS GENERALLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM CDT FRI JUL 19 2013
VFR ON TAP FOR THE DAY TODAY AT ALL TAF SITES. LOW LEVEL MOISTURE
TO REMAIN IN PLACE MOST OF THE DAY OVER THE EASTERN AREAS. DRIER
AIR MOVES INTO THE WESTERN AREAS TODAY WITH VERY DRY CONDITIONS
ABOVE 6000 FEET. WITH GOOD MIXING WOULD NOT BE SURPRISED TO SEE
SKC AT AXN/RWF. THE OTHER SITES SHOULD BE SCATTERED BECOMING SKC
BY EVENING. WITH THE MIXING COMES FAIRLY GUSTY WINDS BY MID
MORNING AND LASTING INTO THE EVENING HOURS. AS A DISTURBANCE
APPROACHES THE STATE SATURDAY MORNING WE WILL SEE A RETURN TO
SCATTERED TO BROKEN CLOUDS AND A CHANCE FOR PRECIPITATION ESPECIALLY IN
THE WEST LATER SATURDAY.
KMSP...VFR THROUGH THE PERIOD. BKN MID DECK SHOULD GIVE WAY TO SCT
THEN FEW BY 00Z. GUSTY NORTHWEST WINDS TODAY.
/OUTLOOK FOR KMSP/
SAT...MAINLY VFR. SLGT CHC -SHRA/-TSRA IN THE LATE AFTERNOON. NW
WINDS 5-10 KTS.
SUN...MAINLY VFR. CHC -SHRA/-TSRA. NE WINDS 5-10 KTS.
MON...MAINLY VFR. CHC -SHRA/TSRA. SE-S WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...LS
AVIATION...DRL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
550 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 541 AM CDT FRI JUL 19 2013
CONVECTION HAS DEVELOPED ACROSS PLATTE AND NANCE COUNTY AND MAY
CONTINUE TO EXPAND ACROSS OUR NORTHERN CWA OVER THE NEXT FEW HOURS
IF THE HRRR IS ACCURATE. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON
THIS SITUATION AND WILL BE SENDING OUT AN UPDATED FORECAST SHORTLY
TO INCLUDE THUNDERSTORMS THIS MORNING ACROSS NORTHERN ZONES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT FRI JUL 19 2013
HOT CONDITIONS WILL PERSIST TODAY...BUT AT LEAST THERE IS FINALLY
A SLIGHT CHANCE OF PRECIPITATION ACROSS PORTIONS OF THE FORECAST
AREA.
A FRONTAL BOUNDARY LOCATED OVER NORTHERN NEBRASKA EARLY THIS
MORNING WILL SLIDE SOUTH AND INTO NORTHERN KANSAS BY LATER THIS
AFTERNOON. THE AIR ALONG AND RIGHT BEHIND THIS FRONT REMAINS HOT
AND THUS DO NOT EXPECT ANY RELIEF FROM THE HEAT TODAY. IN
FACT...THE WIND WILL BECOME RATHER LIGHT IN CLOSE PROXIMITY TO THE
FRONT AND MOISTURE WILL POOL ALONG THE FRONT MAKING FOR A MORE
UNCOMFORTABLE STICKY DAY WITH LESS AIR FLOW TO KEEP YOU COOL.
THERE SHOULD BE A FEW MORE CLOUDS THAN THE PAST SEVERAL DAYS GIVEN
CONVERGENCE ALONG THE FRONT. THE EARLY MORNING RUNS OF THE HRRR
WOULD INDICATE THE POTENTIAL FOR SHOWERS THIS MORNING...BUT MOST
FORECAST MODELS HOLD OFF PRECIPITATION UNTIL AFTERNOON. THE HRRR
HAS BEEN OVERDOING PRECIPITATION THIS MORNING THUS FAR BASED ON
THE LACK OF RADAR ECHOS. HENCE WILL KEEP ACCUMULATING
PRECIPITATION OUT OF THE FORECAST UNTIL AFTERNOON...BUT CAN NOT
COMPLETELY RULE OUT SPRINKLES OR A VERY LIGHT SHOWER THIS
MORNING NEAR THE SFC FRONT.
TONIGHT...THE SFC FRONT WILL BE LOCATED OVER NORTHER KANSAS AND
THIS IS WHERE OUR BEST CHANCE OF RAIN WILL BE...ALTHOUGH IT IS
ONLY A SLIGHT CHANCE OF PRECIPITATION. WILL ALSO NEED TO KEEP AN
EYE OUT TO THE NORTHWEST AS SHOWERS AND THUNDERSTORMS FROM
SOUTHWEST SOUTH DAKOTA AND WESTERN NEBRASKA TRY TO MAKE IT INTO
OUR NORTHERN MOST TIER OF COUNTIES AS WE NEAR DAWN. CURRENT
THINKING BASED ON MOST FORECAST MODELS IS THAT THE NORTHERN
CONVECTION WILL REMAIN NORTH OF OUR FORECAST AREA...BUT WORTH
KEEPING AN EYE ON.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 339 AM CDT FRI JUL 19 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW IS FORECAST TO REMAIN ACROSS THE PLAINS THROUGH THIS
PERIOD. THERE ARE SEVERAL UPPER LEVEL WAVES THAT MOVE THROUGH THE
NORTHWEST FLOW AND EACH OF THEM BRING ANOTHER CHANCE FOR SHOWERS AND
THUNDERSTORMS TO THE AREA. AS IS TYPICAL OF THIS TYPE OF REGIME THE
TIMING AND STRENGTH OF THESE WAVES PLAYS A LARGE PART IN WHERE
PRECIPITATION WILL FALL. MODELS HAVE SLIGHTLY DIFFERENT TIMING OF
THESE WAVES AS THEY MOVE THROUGH THE AREA. THIS GIVES THE RELATIVELY
SMALL POPS FOR NEARLY EVERY PERIOD FOR AT LEAST A PORTION OF THE
AREA.
AT THIS TIME THE STRONGEST AND MOST LIKELY PERIOD FOR THERE TO BE
SOME PRECIPITATION WILL BE DURING THE SATURDAY NIGHT THROUGH SUNDAY
NIGHT TIME FRAME. AN UPPER LEVEL WAVE MOVES INTO THE AREA SATURDAY
AND STRENGTHENS SATURDAY NIGHT. AS THE UPPER WAVE MOVES INTO THE
AREA SATURDAY MORNING THERE IS A CHANCE FOR SOME THUNDERSTORMS IN
THE NORTH...BUT THE MAIN THUNDERSTORMS ARE EXPECTED TO DEVELOP ON
THE HIGH PLAINS DURING THE AFTERNOON AND MOVE INTO THE AREA DURING
THE AFTERNOON AND EVENING. MUCAPE IS THE BEST DURING THE LATE
AFTERNOON INTO THE EVENING AND EXPECT THERE COULD BE SOME STRONG TO
SEVERE STORMS DURING THIS TIME. THE THUNDERSTORMS ARE EXPECTED TO
CONTINUE INTO SUNDAY AND SUNDAY NIGHT AS ANOTHER WAVE MOVES INTO THE
AREA.
THE SAME STORY CONTINUES TO PLAY OUT MONDAY THROUGH TUESDAY NIGHT AS
A SERIES OF UPPER LEVEL WAVES MOVE THROUGH. THESE ARE A LITTLE
WEAKER AND EXPECT THERE MAY BE SOME MORE SPOTTY PRECIPITATION OUT OF
THESE UPPER WAVES. NOT EVERYONE WILL HAVE PRECIPITATION AS THESE
SYSTEMS MOVE THROUGH. WEDNESDAY APPEARS TO BE DRY BEFORE MORE WEAK
UPPER LEVEL WAVES MOVE INTO THE AREA AND SOME SLIGHT CHANCES FOR
THUNDERSTORMS.
TEMPERATURES WILL BE AROUND NORMAL OR JUST A LITTLE ABOVE DURING
THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 541 AM CDT FRI JUL 19 2013
THERE ARE ESSENTIALLY TWO THINGS TO WATCH FOR. THE FIRST WILL BE A
GRADUALLY SHIFTING WIND AS A FRONT PASSES THROUGH. EXPECT A SHIFT
FROM SOUTHWEST...TO NORTH...TO NORTHEAST OVER THE COURSE OF THE
MORNING. THE SECOND AREA OF CONCERN WILL CENTER AROUND THE SLIGHT
CHANCE OF AN ISOLATED THUNDERSTORM. THE BEST CHANCE OF
THUNDERSTORMS WOULD BE FROM LATE MORNING THROUGH MID AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1114 AM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ANOTHER VERY WARM AND MUGGY START TO THE DAY TODAY WITH A FADING
AREA OF HIGH PRESSURE STILL ANCHORED NEAR THE SOUTHEAST COASTLINE.
AN AREA OF LOW PRESSURE NEAR JAMES BAY THIS MORNING IS PUSHING
EASTWARD...WITH SUPPORT FROM AN UPPER LEVEL SHORTWAVE SEEN ON WATER
VAPOR IMAGERY JUST TO THE SOUTHWEST OF HUDSON BAY. A COLD FRONT FROM
THIS AREA OF LOW PRESSURE IS SLICING ACROSS THE NORTHERN PLAINS AND
UPPER GREAT LAKES THIS EARLY MORNING.
AS OF 1000 AM...RADAR SHOWS A LONE SHOWER HAS DEVELOPED ACROSS
THE NORTHEAST SHORELINE OF LAKE ERIE. WHILE THIS STORM SHOULD
STRUGGLE TO MAKE IT ACROSS THE DEVELOPING LAKE SHADOW...EXPANDING
CUMULUS CLOUDS WITH SOME HINT OF QPF FROM THE HRRR AND 00Z RGEM
SUGGEST THERE MAY BE A FEW SHOWERS OR THUNDERSTORMS DEVELOPING
ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER LATE MORNING/EARLY
AFTERNOON. AS WINDS ALOFT INCREASE...THIS ACTIVITY SHOULD GET
PUSHED FURTHER EAST OF THE LAKES...AS SHADOWING BECOMES MORE PRONOUNCED.
OTHERWISE...THE TWO PRIMARY CONCERNS FOR TODAY WILL BE THE HEAT
AND GUSTY WINDS...FOLLOWED BY THE PROSPECTS FOR STRONG
THUNDERSTORMS THIS EVENING AND OVERNIGHT.
TODAY A TIGHTENING PRESSURE GRADIENT BETWEEN THE AREA OF LOW
PRESSURE OVER ONTARIO CANADA AND THE SURFACE HIGH PRESSURE OVER THE
SOUTHEAST WILL BRING GUSTY SOUTHWEST WINDS ACROSS THE CWA. A LOW
LEVEL JET OF 40 TO 45 KNOTS ABOUT 2 TO 3K FEET ABOVE THE SURFACE
WILL PASS OVER THE REGION. WITH PLENTY OF SUNSHINE TODAY INCREASING
MIXING HEIGHTS...UPWARD INTO THIS LLJ GUSTY WINDS WILL BE BROUGHT
DOWN TO THE SURFACE. THE STRONGEST GUSTS WILL BE FOUND ALONG THE
LAKE ERIE SHORELINE AND INLAND ACROSS THE NIAGARA FRONTIER WHERE
FUNNELING UP LAKE ERIE WILL BRING GUSTS IN THE 40 TO 45 MPH RANGE.
WHILE THERE WILL JUST BE ISOLATED GUSTS ABOVE 45 MPH...HAVE DECIDED
TO ISSUE A WIND ADVISORY MORE SO FOR IMPACT OF THESE SUMMERTIME
WINDS SPEEDS...WITH TREES FULLY FOLIATED.
THE OTHER ISSUE FOR TODAY WILL BE THE HEAT. TEMPERATURES ALOFT WILL
RISE ABOUT A DEGREE FROM YESTERDAY WITH 19 TO 20C AIR ABOVE THE
EASTERN GREAT LAKES...AND A SOUTHWESTERLY DOWNSLOPE FLOW WILL BRING
PERHAPS THE HOTTEST DAY OF THE YEAR FOR LOWER ELEVATIONS.
TEMPERATURES WILL RISE TOWARDS 90 DEGREES THROUGH THE REGION...WITH
MID 90S LIKELY ACROSS THE NORTHERN NIAGARA FRONTIER AND TOWARDS THE
GENESEE VALLEY/FINGER LAKES REGION AND THE BLACK RIVER VALLEY. A
DOWNSLOPE FLOW ACROSS THE LOWER ELEVATIONS MAY BRING SPOTS TO NEAR
RECORD HEAT FOR THE DAY. WITH A MOIST AIRMASS REMAINING...DEWPOINTS
INTO THE LOWER 70S APPARENT TEMPERATURES WILL RISE ABOVE 100F FOR
MUCH OF OUR CWA. HAVE ALSO ISSUED A HEAT ADVISORY FOR NIAGARA
COUNTY...EASTWARD ACROSS ORLEANS/GENESEE AND INTO THE GENESEE VALLEY
AND FINGER LAKES REGION. OUTSIDE THIS AREA IT WILL STILL BE HOT WITH
APPARENT TEMPERATURES INTO THE 90S.
STRONG SOUTHWEST FLOW WILL BRING THE LAKE ERIE BREEZE WELL INLAND
TODAY AND SHADOW AREAS DOWNWIND OF BOTH GREAT LAKES. THE LACK OF
UPPER LEVEL SUPPORT FOR THUNDERSTORMS WILL AGAIN BRING THE PRIMARY
FOCUS FOR LIFT UPON THESE LAKE BREEZE BOUNDARIES...WITH SOME
ADDITIONAL LIFT FROM THE APPROACHING LLJ AND THE CONVERGENCE ALONG
THIS JET. A FEW THUNDERSTORMS ARE POSSIBLE ACROSS WELL INLAND
AREAS...AND ACROSS THE EASTERN LAKE ONTARIO REGION THIS AFTERNOON.
TONIGHT THE CONCERN WILL SHIFT FROM THE HEAT AND WINDS TO THE
THUNDERSTORMS THAT WILL BE FORMING ALONG A PRE FRONTAL TROUGH WELL
AHEAD OF THE MAIN COLD FRONT. THE TIMING OF THIS SURFACE TROUGH AND
SHOWER AND THUNDERSTORM ACTIVITY BRINGS IT INTO OUR REGION AFTER THE
PEAK DAYTIME HEATING. STILL SBCAPES OF 1000 TO 2000 J/KG WILL REMAIN
IN THIS VERY WARM AIRMASS...AND INCREASING MID LEVEL MOISTURE WILL
FUEL SHOWERS AND THUNDERSTORMS DROPPING SOUTHEASTWARD ACROSS THE
CWA.
ALOFT DYNAMICS BECOME A LITTLE MORE FAVORABLE FOR WIDESPREAD SHOWERS
AND THUNDERSTORMS TONIGHT WITH A 120 KNOT 250 HPA JET CENTERED OVER
QUEBEC WITH OUR EASTERN GREAT LAKES REGION WITHIN THE RIGHT ENTRANCE
REGION. THERE WILL ALSO BE FALLING HEIGHTS ALOFT AHEAD OF THE
SHORTWAVE THAT WILL SLIDE SOUTHWARD DOWN THE WEST SIDE OF HUDSON BAY
TODAY AND TOWARDS THE UPPER GREAT LAKES TONIGHT.
A STILL STRONG LLJ OF 35 TO 40 KNOTS WILL REMAIN ACROSS THE
CWA...AND THIS JET COMBINED WITH DOWNDRAFTS FROM THUNDERSTORMS WILL
POSE THE PROSPECTS FOR GUSTY TO DAMAGING WINDS WITH THE OVERNIGHT
CONVECTION. WILL CONTINUE TO MENTION GUSTY WINDS IN THE GRIDS ALONG
WITH THE HEAVY RAINFALL AS PWATS CLIMB TOWARDS 1.75 TO 2.00 INCHES.
WHILE THUNDERSTORMS ARE LIKELY ACROSS MUCH OF THE CWA TONIGHT...WILL
PLACE JUST A HIGH CHANCE ACROSS THE FAR SOUTHERN GENESEE VALLEY
WHICH WILL REMAIN SOUTH OF THE BEST UPPER LEVEL DYNAMICS...AND
EASTWARD OF THE SURFACE TROUGH.
THE COLD FRONT WILL ONLY REACH FROM ABOUT QUEBEC...TO DETROIT TO
CENTRAL ILLINOIS BY 12Z SATURDAY. THIS WILL LEAVE OUR REGION STILL
WITHIN THE WARM SECTOR WITH OVERNIGHT LOWS REMAINING IN THE 70S.
WITH WARM TEMPERATURES THROUGH 1 AM EDT...SOME OF OUR CLIMATE
SITES MAY SET NOT ONLY DAILY...BUT NEAR MONTHLY RECORD HIGH
MINIMUMS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE MAIN STORY THIS WEEKEND WILL BE THE PASSAGE OF A COLD FRONT THAT
WILL BREAK THE HEAT WAVE THE REGION HAS BEEN EXPERIENCING OF LATE
AND USHER IN A RETURN TO MUCH MORE SEASONABLE TEMPERATURES. AS WE
OPEN THE WEEKEND SATURDAY MORNING HOWEVER...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL STILL
LIKELY BE CROSSING THE FORECAST AREA. THIS INITIAL BATCH OF
CONVECTIVE ACTIVITY SHOULD TAPER OFF FROM NORTHWEST TO SOUTHEAST
DURING THE MORNING HOURS WITH THE PASSAGE OF THE TROUGH...HOWEVER A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
DURING THE AFTERNOON/EARLY EVENING HOURS ACCOMPANYING THE PASSAGE OF
THE ACTUAL COLD FRONT. WITH THE LOW LEVEL JET WELL TO OUR EAST AND
MODEL CAPES ONLY IN THE 500-1000 J/KG RANGE...ANY SHOWERS AND
THUNDERSTORMS THAT DO OCCUR SHOULD REMAIN RELATIVELY BENIGN. THE
COMBINATION OF CLOUD COVER AND THE GRADUAL FILTERING OF COOLER AIR
INTO THE REGION BEHIND THE PRE-FRONTAL TROUGH MEANS THAT MOST AREAS
SHOULD ONLY TOP OUT IN THE LOWER 80S...THOUGH AREAS SOUTHEAST OF
LAKE ONTARIO COULD STILL SEE HIGHS IN THE MID 80S THANKS TO
DOWNSLOPING SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN/NORTH CENTRAL NEW YORK SATURDAY
EVENING BRINGING AN END TO ANY LINGERING PRECIPITATION AS MUCH
COOLER AND DRIER AIR ADVECTS INTO THE REGION. WITH THE MUCH
ANTICIPATED ARRIVAL OF THIS AIRMASS LOOK FOR TEMPERATURES TO DIP
INTO THE MID 50S ACROSS THE NORTH COUNTRY AND SOUTHERN TIER WHILE
THE LAKE PLAINS AND FINGER LAKES WILL COOL INTO THE LOWER 60S. THE
COOLING TEMPERATURES COMBINED WITH ANY LINGERING MOISTURE FROM
FRIDAY NIGHT/SATURDAY/S RAINFALL COULD LEAD TO PATCHY FOG ACROSS THE
SOUTHERN TIER.
DRY AND MILD WEATHER WILL PREVAIL ON SUNDAY AND SUNDAY NIGHT AS HIGH
PRESSURE SETTLES OVER THE GREAT LAKES IN THE WAKE OF THE COLD FRONT.
HIGHS IN THE MID TO UPPER 70S ON SUNDAY WILL PROVIDE A REFRESHING
BREAK FROM THE RECENT HEAT. WHILE MOST AREAS SHOULD SEE PLENTY OF
SUNSHINE...WITH 850MB TEMPERATURES COOLING TO THE +8 TO +10C RANGE
AND LAKE TEMPERATURES RUNNING A TOASTY +25C...CANNOT RULE OUT THE
POSSIBILITY OF SOME LAKE INDUCED CLOUD COVER CREEPING INTO WESTERN
NEW YORK. ANY LAKE INDUCED CLOUD COVER SHOULD DIMINISH SUNDAY
EVENING AS WINDS VEER TO TO THE EAST...HOWEVER EXPECT MID/HIGH
CLOUDS TO MOVE IN FROM THE WEST LATER SUNDAY NIGHT AHEAD OF A WEAK
SHORTWAVE CROSSING THE CENTRAL GREAT LAKES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
BY MONDAY HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST...
ALLOWING SOUTHERLY RETURN FLOW TO BEGIN. MODELS CONTINUE TO BE A
LITTLE MORE AGGRESSIVE IN BRINGING A PLUME OF DEEPER MOISTURE AND
PERHAPS A FEW SHOWERS INTO EASTERN PA AND NY...BUT IT STILL APPEARS
THIS WILL REMAIN MAINLY TO OUR EAST. HAVE CONTINUED WITH A DRY
FORECAST FOR MONDAY WITH TEMPERATURES MODERATING TO VERY CLOSE TO
AVERAGE.
TUESDAY THROUGH THURSDAY A BROAD TROUGH WILL SLOWLY EVOLVE IN THE
GREAT LAKES. NUMEROUS SHORTWAVE FEATURES WILL ROTATE THROUGH THE
DEVELOPING TROUGH...BUT MODEL GUIDANCE REMAINS OUT OF PHASE WITH
RESPECT TO TIMING AND AMPLITUDE OF THESE FEATURES. AT THIS POINT
HAVE JUST BLANKETED THE PERIOD WITH LOW CHANCE POPS UNTIL BETTER
MODEL AGREEMENT ALLOWS FOR MORE REFINED TIMING. TEMPERATURES WILL
RETURN TO A LITTLE ABOVE AVERAGE AND HUMIDITY WILL INCREASE...BUT
BOTH WILL REMAIN BELOW THE LEVELS OF THIS WEEK.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR FLIGHT CONDITIONS WERE IN PLACE AT 15Z ACROSS THE
REGION...WITH SOME BKN CIGS AROUND 3K FEET ACROSS THE SOUTHERN
TIER NEAR JHW.
THE PRESSURE GRADIENT WILL INCREASE TODAY IN ADVANCE OF AN
APPROACHING COLD FRONT SAGGING SOUTHWARD ACROSS ONTARIO PROVINCE...
WHICH WILL RESULT IN RATHER BREEZY TO WINDY CONDITIONS DEVELOPING
ACROSS THE AREA DURING THE MORNING...THEN CONTINUING THROUGH THE
AFTERNOON. EXPECT SOUTHWESTERLY SURFACE WINDS TO INCREASE TO 15-25
KTS WITH GUSTS TO AS HIGH AS 35-40 KTS BY EARLY AFTERNOON...WITH
THE STRONGEST WINDS MOST LIKELY DOWNWIND OF LAKE ERIE FROM
KBUF/KIAG OVER TO KROC.
WITH THE DEVELOPING STRONGER SOUTHWESTERLY FLOW...LAKE SHADOWS WILL
QUICKLY DEVELOP AND SPREAD ACROSS MUCH OF THE AREA THIS AFTERNOON...
THEREBY LIMITING ANY POTENTIAL FOR CONVECTION TO FAR SOUTHERN
PORTIONS OF THE SOUTHERN TIER/FINGER LAKES AND INTERIOR PORTIONS OF
THE NORTH COUNTRY FOR THE VAST MAJORITY OF THE DAY. THROUGH THE
EVENING HOURS CONVECTION WILL BEGIN TO EDGE INTO WNY AS WELL AS THE
NORTH COUNTRY. EXPECT CONDITIONS TO DROP TO MVFR OVERNIGHT AS
THE RAIN SHOWERS PRESS SOUTHEASTWARD ACROSS THE EASTERN GREAT LAKES
REGION. WITH INSTABILITY REMAINING THERE WILL ALSO LIKELY BE
THUNDERSTORMS ACCOMPANYING THE PRECIPITATION. RAIN SHOWERS WITH
THUNDERSTORMS WILL THEN CONTINUE TO FALL THROUGH THE END OF THE TAF
CYCLE. ANY OF THESE STORMS COULD BEING BRIEF PERIODS OF IFR FLIGHT
CONDITIONS.
OUTLOOK...
SATURDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS IS LIKELY WITH
ASSOCIATED IFR/MVFR...WITH MAINLY VFR CONDITIONS OTHERWISE.
SUNDAY AND MONDAY...VFR.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LOZ042-
043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...WOOD
LONG TERM...HITCHCOCK
AVIATION...APFFEL/THOMAS
MARINE...APFFEL/THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1031 AM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ANOTHER VERY WARM AND MUGGY START TO THE DAY TODAY WITH A FADING
AREA OF HIGH PRESSURE STILL ANCHORED NEAR THE SOUTHEAST COASTLINE.
AN AREA OF LOW PRESSURE NEAR JAMES BAY THIS MORNING IS PUSHING
EASTWARD...WITH SUPPORT FROM AN UPPER LEVEL SHORTWAVE SEEN ON WATER
VAPOR IMAGERY JUST TO THE SOUTHWEST OF HUDSON BAY. A COLD FRONT FROM
THIS AREA OF LOW PRESSURE IS SLICING ACROSS THE NORTHERN PLAINS AND
UPPER GREAT LAKES THIS EARLY MORNING.
AS OF 1000 AM...RADAR SHOWS A LONE SHOWER HAS DEVELOPED ACROSS
THE NORTHEAST SHORELINE OF LAKE ERIE. WHILE THIS STORM SHOULD
STRUGGLE TO MAKE IT ACROSS THE DEVELOPING LAKE SHADOW...EXPANDING
CUMULUS CLOUDS WITH SOME HINT OF QPF FROM THE HRRR AND 00Z RGEM
SUGGEST THERE MAY BE A FEW SHOWERS OR THUNDERSTORMS DEVELOPING
ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER LATE MORNING/EARLY
AFTERNOON. AS WINDS ALOFT INCREASE...THIS ACTIVITY SHOULD GET
PUSHED FURTHER EAST OF THE LAKES...AS SHADOWING BECOMES MORE PRONOUNCED.
OTHERWISE...THE TWO PRIMARY CONCERNS FOR TODAY WILL BE THE HEAT
AND GUSTY WINDS...FOLLOWED BY THE PROSPECTS FOR STRONG
THUNDERSTORMS THIS EVENING AND OVERNIGHT.
TODAY A TIGHTENING PRESSURE GRADIENT BETWEEN THE AREA OF LOW
PRESSURE OVER ONTARIO CANADA AND THE SURFACE HIGH PRESSURE OVER THE
SOUTHEAST WILL BRING GUSTY SOUTHWEST WINDS ACROSS THE CWA. A LOW
LEVEL JET OF 40 TO 45 KNOTS ABOUT 2 TO 3K FEET ABOVE THE SURFACE
WILL PASS OVER THE REGION. WITH PLENTY OF SUNSHINE TODAY INCREASING
MIXING HEIGHTS...UPWARD INTO THIS LLJ GUSTY WINDS WILL BE BROUGHT
DOWN TO THE SURFACE. THE STRONGEST GUSTS WILL BE FOUND ALONG THE
LAKE ERIE SHORELINE AND INLAND ACROSS THE NIAGARA FRONTIER WHERE
FUNNELING UP LAKE ERIE WILL BRING GUSTS IN THE 40 TO 45 MPH RANGE.
WHILE THERE WILL JUST BE ISOLATED GUSTS ABOVE 45 MPH...HAVE DECIDED
TO ISSUE A WIND ADVISORY MORE SO FOR IMPACT OF THESE SUMMERTIME
WINDS SPEEDS...WITH TREES FULLY FOLIATED.
THE OTHER ISSUE FOR TODAY WILL BE THE HEAT. TEMPERATURES ALOFT WILL
RISE ABOUT A DEGREE FROM YESTERDAY WITH 19 TO 20C AIR ABOVE THE
EASTERN GREAT LAKES...AND A SOUTHWESTERLY DOWNSLOPE FLOW WILL BRING
PERHAPS THE HOTTEST DAY OF THE YEAR FOR LOWER ELEVATIONS.
TEMPERATURES WILL RISE TOWARDS 90 DEGREES THROUGH THE REGION...WITH
MID 90S LIKELY ACROSS THE NORTHERN NIAGARA FRONTIER AND TOWARDS THE
GENESEE VALLEY/FINGER LAKES REGION AND THE BLACK RIVER VALLEY. A
DOWNSLOPE FLOW ACROSS THE LOWER ELEVATIONS MAY BRING SPOTS TO NEAR
RECORD HEAT FOR THE DAY. WITH A MOIST AIRMASS REMAINING...DEWPOINTS
INTO THE LOWER 70S APPARENT TEMPERATURES WILL RISE ABOVE 100F FOR
MUCH OF OUR CWA. HAVE ALSO ISSUED A HEAT ADVISORY FOR NIAGARA
COUNTY...EASTWARD ACROSS ORLEANS/GENESEE AND INTO THE GENESEE VALLEY
AND FINGER LAKES REGION. OUTSIDE THIS AREA IT WILL STILL BE HOT WITH
APPARENT TEMPERATURES INTO THE 90S.
STRONG SOUTHWEST FLOW WILL BRING THE LAKE ERIE BREEZE WELL INLAND
TODAY AND SHADOW AREAS DOWNWIND OF BOTH GREAT LAKES. THE LACK OF
UPPER LEVEL SUPPORT FOR THUNDERSTORMS WILL AGAIN BRING THE PRIMARY
FOCUS FOR LIFT UPON THESE LAKE BREEZE BOUNDARIES...WITH SOME
ADDITIONAL LIFT FROM THE APPROACHING LLJ AND THE CONVERGENCE ALONG
THIS JET. A FEW THUNDERSTORMS ARE POSSIBLE ACROSS WELL INLAND
AREAS...AND ACROSS THE EASTERN LAKE ONTARIO REGION THIS AFTERNOON.
TONIGHT THE CONCERN WILL SHIFT FROM THE HEAT AND WINDS TO THE
THUNDERSTORMS THAT WILL BE FORMING ALONG A PRE FRONTAL TROUGH WELL
AHEAD OF THE MAIN COLD FRONT. THE TIMING OF THIS SURFACE TROUGH AND
SHOWER AND THUNDERSTORM ACTIVITY BRINGS IT INTO OUR REGION AFTER THE
PEAK DAYTIME HEATING. STILL SBCAPES OF 1000 TO 2000 J/KG WILL REMAIN
IN THIS VERY WARM AIRMASS...AND INCREASING MID LEVEL MOISTURE WILL
FUEL SHOWERS AND THUNDERSTORMS DROPPING SOUTHEASTWARD ACROSS THE
CWA.
ALOFT DYNAMICS BECOME A LITTLE MORE FAVORABLE FOR WIDESPREAD SHOWERS
AND THUNDERSTORMS TONIGHT WITH A 120 KNOT 250 HPA JET CENTERED OVER
QUEBEC WITH OUR EASTERN GREAT LAKES REGION WITHIN THE RIGHT ENTRANCE
REGION. THERE WILL ALSO BE FALLING HEIGHTS ALOFT AHEAD OF THE
SHORTWAVE THAT WILL SLIDE SOUTHWARD DOWN THE WEST SIDE OF HUDSON BAY
TODAY AND TOWARDS THE UPPER GREAT LAKES TONIGHT.
A STILL STRONG LLJ OF 35 TO 40 KNOTS WILL REMAIN ACROSS THE
CWA...AND THIS JET COMBINED WITH DOWNDRAFTS FROM THUNDERSTORMS WILL
POSE THE PROSPECTS FOR GUSTY TO DAMAGING WINDS WITH THE OVERNIGHT
CONVECTION. WILL CONTINUE TO MENTION GUSTY WINDS IN THE GRIDS ALONG
WITH THE HEAVY RAINFALL AS PWATS CLIMB TOWARDS 1.75 TO 2.00 INCHES.
WHILE THUNDERSTORMS ARE LIKELY ACROSS MUCH OF THE CWA TONIGHT...WILL
PLACE JUST A HIGH CHANCE ACROSS THE FAR SOUTHERN GENESEE VALLEY
WHICH WILL REMAIN SOUTH OF THE BEST UPPER LEVEL DYNAMICS...AND
EASTWARD OF THE SURFACE TROUGH.
THE COLD FRONT WILL ONLY REACH FROM ABOUT QUEBEC...TO DETROIT TO
CENTRAL ILLINOIS BY 12Z SATURDAY. THIS WILL LEAVE OUR REGION STILL
WITHIN THE WARM SECTOR WITH OVERNIGHT LOWS REMAINING IN THE 70S.
WITH WARM TEMPERATURES THROUGH 1 AM EDT...SOME OF OUR CLIMATE
SITES MAY SET NOT ONLY DAILY...BUT NEAR MONTHLY RECORD HIGH
MINIMUMS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE MAIN STORY THIS WEEKEND WILL BE THE PASSAGE OF A COLD FRONT THAT
WILL BREAK THE HEAT WAVE THE REGION HAS BEEN EXPERIENCING OF LATE
AND USHER IN A RETURN TO MUCH MORE SEASONABLE TEMPERATURES. AS WE
OPEN THE WEEKEND SATURDAY MORNING HOWEVER...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL STILL
LIKELY BE CROSSING THE FORECAST AREA. THIS INITIAL BATCH OF
CONVECTIVE ACTIVITY SHOULD TAPER OFF FROM NORTHWEST TO SOUTHEAST
DURING THE MORNING HOURS WITH THE PASSAGE OF THE TROUGH...HOWEVER A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
DURING THE AFTERNOON/EARLY EVENING HOURS ACCOMPANYING THE PASSAGE OF
THE ACTUAL COLD FRONT. WITH THE LOW LEVEL JET WELL TO OUR EAST AND
MODEL CAPES ONLY IN THE 500-1000 J/KG RANGE...ANY SHOWERS AND
THUNDERSTORMS THAT DO OCCUR SHOULD REMAIN RELATIVELY BENIGN. THE
COMBINATION OF CLOUD COVER AND THE GRADUAL FILTERING OF COOLER AIR
INTO THE REGION BEHIND THE PRE-FRONTAL TROUGH MEANS THAT MOST AREAS
SHOULD ONLY TOP OUT IN THE LOWER 80S...THOUGH AREAS SOUTHEAST OF
LAKE ONTARIO COULD STILL SEE HIGHS IN THE MID 80S THANKS TO
DOWNSLOPING SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN/NORTH CENTRAL NEW YORK SATURDAY
EVENING BRINGING AN END TO ANY LINGERING PRECIPITATION AS MUCH
COOLER AND DRIER AIR ADVECTS INTO THE REGION. WITH THE MUCH
ANTICIPATED ARRIVAL OF THIS AIRMASS LOOK FOR TEMPERATURES TO DIP
INTO THE MID 50S ACROSS THE NORTH COUNTRY AND SOUTHERN TIER WHILE
THE LAKE PLAINS AND FINGER LAKES WILL COOL INTO THE LOWER 60S. THE
COOLING TEMPERATURES COMBINED WITH ANY LINGERING MOISTURE FROM
FRIDAY NIGHT/SATURDAY/S RAINFALL COULD LEAD TO PATCHY FOG ACROSS THE
SOUTHERN TIER.
DRY AND MILD WEATHER WILL PREVAIL ON SUNDAY AND SUNDAY NIGHT AS HIGH
PRESSURE SETTLES OVER THE GREAT LAKES IN THE WAKE OF THE COLD FRONT.
HIGHS IN THE MID TO UPPER 70S ON SUNDAY WILL PROVIDE A REFRESHING
BREAK FROM THE RECENT HEAT. WHILE MOST AREAS SHOULD SEE PLENTY OF
SUNSHINE...WITH 850MB TEMPERATURES COOLING TO THE +8 TO +10C RANGE
AND LAKE TEMPERATURES RUNNING A TOASTY +25C...CANNOT RULE OUT THE
POSSIBILITY OF SOME LAKE INDUCED CLOUD COVER CREEPING INTO WESTERN
NEW YORK. ANY LAKE INDUCED CLOUD COVER SHOULD DIMINISH SUNDAY
EVENING AS WINDS VEER TO TO THE EAST...HOWEVER EXPECT MID/HIGH
CLOUDS TO MOVE IN FROM THE WEST LATER SUNDAY NIGHT AHEAD OF A WEAK
SHORTWAVE CROSSING THE CENTRAL GREAT LAKES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
BY MONDAY HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST...
ALLOWING SOUTHERLY RETURN FLOW TO BEGIN. MODELS CONTINUE TO BE A
LITTLE MORE AGGRESSIVE IN BRINGING A PLUME OF DEEPER MOISTURE AND
PERHAPS A FEW SHOWERS INTO EASTERN PA AND NY...BUT IT STILL APPEARS
THIS WILL REMAIN MAINLY TO OUR EAST. HAVE CONTINUED WITH A DRY
FORECAST FOR MONDAY WITH TEMPERATURES MODERATING TO VERY CLOSE TO
AVERAGE.
TUESDAY THROUGH THURSDAY A BROAD TROUGH WILL SLOWLY EVOLVE IN THE
GREAT LAKES. NUMEROUS SHORTWAVE FEATURES WILL ROTATE THROUGH THE
DEVELOPING TROUGH...BUT MODEL GUIDANCE REMAINS OUT OF PHASE WITH
RESPECT TO TIMING AND AMPLITUDE OF THESE FEATURES. AT THIS POINT
HAVE JUST BLANKETED THE PERIOD WITH LOW CHANCE POPS UNTIL BETTER
MODEL AGREEMENT ALLOWS FOR MORE REFINED TIMING. TEMPERATURES WILL
RETURN TO A LITTLE ABOVE AVERAGE AND HUMIDITY WILL INCREASE...BUT
BOTH WILL REMAIN BELOW THE LEVELS OF THIS WEEK.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR FLIGHT CONDITIONS WERE FOUND AT 12Z ACROSS THE REGION...AND
THESE CONDITIONS SHOULD PREVAIL THROUGH MUCH OF THE FIRST 12 TO 18
HOURS OF THIS TAF CYCLE.
THE PRESSURE GRADIENT WILL INCREASE TODAY IN ADVANCE OF AN
APPROACHING COLD FRONT SAGGING SOUTHWARD ACROSS ONTARIO PROVINCE...
WHICH WILL RESULT IN RATHER BREEZY TO WINDY CONDITIONS DEVELOPING
ACROSS THE AREA DURING THE MORNING...THEN CONTINUING THROUGH THE
AFTERNOON. EXPECT SOUTHWESTERLY SURFACE WINDS TO INCREASE TO 15-25
KTS WITH GUSTS TO AS HIGH AS 35-40 KTS BY LATE MORNING/EARLY
AFTERNOON...WITH THE STRONGEST WINDS MOST LIKELY DOWNWIND OF LAKE
ERIE FROM KBUF/KIAG OVER TO KROC.
WITH THE DEVELOPING STRONGER SOUTHWESTERLY FLOW...LAKE SHADOWS WILL
QUICKLY DEVELOP AND SPREAD ACROSS MUCH OF THE AREA THIS AFTERNOON...
THEREBY LIMITING ANY POTENTIAL FOR CONVECTION TO FAR SOUTHERN
PORTIONS OF THE SOUTHERN TIER/FINGER LAKES AND INTERIOR PORTIONS OF
THE NORTH COUNTRY FOR THE VAST MAJORITY OF THE DAY. THROUGH THE
EVENING HOURS CONVECTION WILL BEGIN TO EDGE INTO WNY AS WELL AS THE
NORTH COUNTRY. EXPECT CONDITIONS TO DROP TO MVFR OVERNIGHT AS
THE RAIN SHOWERS PRESS SOUTHEASTWARD ACROSS THE EASTERN GREAT LAKES
REGION. WITH INSTABILITY REMAINING THERE WILL ALSO LIKELY BE
THUNDERSTORMS ACCOMPANYING THE PRECIPITATION. RAIN SHOWERS WITH
THUNDERSTORMS WILL THEN CONTINUE TO FALL THROUGH THE END OF THE TAF
CYCLE. ANY OF THESE STORMS COULD BEING BRIEF PERIODS OF IFR FLIGHT
CONDITIONS.
OUTLOOK...
SATURDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS IS LIKELY WITH
ASSOCIATED IFR/MVFR...WITH MAINLY VFR CONDITIONS OTHERWISE.
SUNDAY AND MONDAY...VFR.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LOZ042-
043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...WOOD
LONG TERM...HITCHCOCK
AVIATION...THOMAS
MARINE...THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EDT FRI JUL 19 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE CAROLINAS ON SUNDAY AND THEN STALL
ACROSS THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM FRIDAY...
12Z SOUNDINGS FROM AROUND THE AREA SHOWED A MODEST CAP AROUND 700MB
AT KMHX...WITH THE CAP AT THAT LEVEL MUCH WEAKER TOWARD KGSO GIVEN
TEMPERATURES 2C TO 3C COOLER. THE LATEST RUC INDICATES GENERAL
SUBSIDENCE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...WITH WEAK
WINDS ALOFT AND THE MOST FAVORABLE ITEMS FOR ANY RELATIVELY DEEP
LIFT BEING THE SURFACE TROUGH LINGERING OVER THE WESTERN PIEDMONT...
COUPLED WITH A WEAK 850MB TROUGH IN THE SAME AREA AND AVAILABLE
LOW-LEVEL MOISTURE. OVERALL MOISTURE SHOULD BE BEST TOWARD THE
NORTHWEST PIEDMONT LATER THIS AFTERNOON WHERE HIGHER 850MB THETA-E
VALUES ARE FORECAST. IT IS ALSO IN THAT LOCATION WHERE THE BETTER
1000-500MB LAPSE RATES ARE FORECAST...NEAR 6.75C/KM...AND WHERE THE
BETTER INSTABILITY LIES...2000-2500J/KG VERSUS A FORECAST OF ONLY
1000-1500J/KG TOWARD THE COASTAL PLAIN. CONVECTION-ALLOWING
MODELS...GIVEN THE GENERAL SUBSIDENCE...ARE MOSTLY RELUCTANT TO
FORECAST MUCH PRECIPITATION IN CENTRAL NORTH CAROLINA...BUT WITHIN
THE SLIGHT CHANCE RANGE...THE BETTER CHANCE SHOULD MAINLY BE ALONG
AND NORTH/WEST OF INTERSTATE 85. AS NOTED PREVIOUSLY...WEAK WINDS
ALOFT WILL ALLOW ANY OF THE ISOLATED STORMS TO MOVE ONLY VERY
SLOWLY. 1000-850MB THICKNESSES AT 12Z AND FORECAST LATE THIS
AFTERNOON ARE BASICALLY PERSISTENCE FROM THURSDAY...AND HAVE
FORECAST HIGHS CLOSE TO THOSE OF THURSDAY AS A RESULT. THIS PLACES
MOST LOCATIONS WITH HEAT INDICES AROUND 100...A COUPLE OF DEGREES
WARMER TOWARD KIXA AND KRZZ. ANY THUNDERSTORMS SHOULD DIMINISH
DIURNALLY...WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 245 AM FRIDAY...
THE NORTHERN STREAM TROUGH AND ASSOCIATED SFC COLD FRONT WILL REMAIN
NORTH OF THE AREA...SAGGING SOUTH INTO THE SOUTHERN OHIO VALLEY AND
NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING. NOT MANY DIFFERENCES
BETWEEN TODAY AND SATURDAY WITH THE SAME MESOSCALE FORCING DRIVING
ISOLATED TO SCATTERED DIURNAL CONVECTION SATURDAY AFTERNOON
HIGHS IN THE LOWER 90S. LOWS IN THE LOWER TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
SUNDAY THROUGH THURSDAY:
THIS PERIOD WILL BE DOMINATED BY A SURFACE TROUGH/FRONTAL BOUNDARY
STALLING OVER THE MID ATLANTIC...WITH THE UPPER LEVEL TROUGH DIGGING
SOUTH INTO CENTRAL NC. GOOD MOISTURE ADVECTION FROM THE GULF IN
SOUTHWEST FLOW ALONG THE TROUGH AXIS WILL MOISTEN THE COLUMN...WITH
PW`S AROUND TWO INCHES FORECAST THROUGH TUESDAY NIGHT. DISTURBANCES
TRACKING OVER THE AREA ALONG THE BASE OF THE MID/UPPER TROUGH WILL
BE SUFFICIENT TO INITIATE CONVECTION...ESPECIALLY DURING THE
AFT/EVE...GIVEN THE MOIST AND UNSTABLE AIRMASS IN PLACE. CONFIDENCE
ON EXACTLY WHERE THE BEST CHANCES/COVERAGE OF SHOWERS AND STORMS
WILL OCCUR IS STILL LOW GIVEN THE UNCERTAINTY OF WHERE THE FRONT
WILL STALL. FOR NOW WILL CONTINUE TO CARRY AT LEAST A CHANCE OF
SHOWERS AND STORMS THROUGH THE PERIOD...WITH HIGHEST CHANCES DURING
THE AFT/EVE. WITH THE CURRENT CHANCES OF CONVECTION AND GIVEN THE
INCREASE IN MOISTURE EXPECTED...CLOUDY CONDITIONS WILL BE LIKELY
OVER CENTRAL NC DURING THIS TIME. TAKING CLOUDS AND PRECIP INTO
ACCOUNT...HIGH TEMPS IN THE MID 80S TO NEAR 90 DEGREES AND OVERNIGHT
LOWS IN THE UPPER 60S TO LOW 70S ARE EXPECTED THROUGH THE PERIOD.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 1020 AM FRIDAY...
VFR CONDITIONS WILL PREVAIL OUTSIDE OF ANY AFTERNOON AND EVENING
SHOWER OR THUNDERSTORM. DEEP CONVECTIVE COVERAGE THIS AFTERNOON AND
EVENING IS EXPECTED TO BE RATHER ISOLATED AND THUS HAVE OMITTED ANY
MENTION OF SHOWERS OR THUNDER FROM ALL TAF SITES.
BEYOND THE 24 HOUR TAF PERIOD:
OUTSIDE OF SOME EARLY MORNING FOG/STRATUS SATURDAY...VFR CONDITIONS
SHOULD PREVAIL WITH ONLY ISOLATED AFTERNOON STORMS. A SLOW MOVING
COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST ON SUNDAY AND
WILL STALL ACROSS THE AREA THROUGH EARLY NEXT WEEK. THIS WILL RESULT
IN NUMEROUS SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS...WITH SUB VFR CONDITIONS IN HEAVY RAIN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...CBL/DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
944 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 932 AM CDT FRI JUL 19 2013
FRIDAY MORNING...THE CURRENT WEATHER CONDITIONS WERE DEFINED BY A
POST FRONTAL ENVIRONMENT WITH MOSTLY CLEAR SKIES AND LIGHT
NORTHWEST WINDS. THIS UPDATE WILL BE MAINLY TO PROVIDE CURRENT
TEMPERATURES AND RELATIVE HUMIDITY. THIS AFTERNOON...ANOTHER
FRONTAL SYSTEM WILL APPROACH FROM THE NORTHWEST AND BRING A SLIGHT
CHANCE FOR THUNDERSTORMS. CURRENT FORECAST LOOKS GOOD IN THIS
REGARD.
UPDATE ISSUED AT 627 AM CDT FRI JUL 19 2013
NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. CLEAR SKIES ACROSS
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING SO LOWERED
CLOUD COVER THIS MORNING ACROSS THE NORTH. DO EXPECT INCREASING
CLOUDS NORTH BY MID MORNING WITH SHOWER AND THUNDERSTORM CHANCES
HOLDING OFF UNTIL AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 932 AM CDT FRI JUL 19 2013
AT 9 AM CDT...VFR CONDITIONS WITH CLEAR SKIES COVERED THE REGION.
LATE THIS AFTERNOON ANOTHER WEAK COLD FRONTAL BOUNDARY WILL
APPROACH THE STATE FROM THE NORTHWEST. THE FRONT WILL BE THE
FOCUS FOR WIDELY SCATTERED THUNDERSTORMS. AT THIS TIME...TO MUCH
UNCERTAINTY TO ADD THUNDERSTORMS TO THE TAF. CURRENT 12Z TAFS
EXPRESS THE THUNDERSTORM THREAT AS VCTS (VICINITY) THUNDERSTORMS
AFTER 22Z NORTH AND AFTER 00Z SOUTH. WILL RE EVALUATE THE TIMING
FOR THE 18Z TAF ISSUANCE BUT THREAT WILL PROBABLY BE TO ISOLATED
TO ADD MORE DEFINITION THAN CURRENT TAFS EXPRESS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
627 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 627 AM CDT FRI JUL 19 2013
NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. CLEAR SKIES ACROSS
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING SO LOWERED
CLOUD COVER THIS MORNING ACROSS THE NORTH. DO EXPECT INCREASING
CLOUDS NORTH BY MID MORNING WITH SHOWER AND THUNDERSTORM CHANCES
HOLDING OFF UNTIL AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM CDT FRI JUL 19 2013
VFR CONDITIONS ARE FORECAST FOR THE 12 UTC TAF CYCLE OUTSIDE OF
THUNDERSTORMS. INCLUDED VCTS FOR KISN AND KMOT BY 22-00 UTC AND KJMS
AND KBIS BY 00-02 UTC AS A COLD FRONT MOVES SOUTH OUT OF CANADA.
LEFT THE MENTION OF THUNDER OUT FOR NOW AT KDIK DUE TO UNCERTAINTY
IN IMPACTS TO THE TERMINAL AS THE GREATER CHANCES FOR THUNDERSTORMS
LOOK TO BE NORTH AND EAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1002 AM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID AIRMASS OVER THE REGION WILL BREAK DOWN TONIGHT AS A
COLD FRONT MOVES INTO THE REGION. STORMS WILL ACCOMPANY THE FRONT
AS IT MOVES THROUGH THE AREA ON SATURDAY. COOLER AND DRIER WEATHER
ON TAP FOR SUNDAY...BUT THE HUMIDITY WILL RETURN EARLY NEXT WEEK.
TEMPERATURES WILL BE MORE COMFORTABLE WITH HIGHS AT OR SLIGHTLY
BELOW NORMAL THROUGH MOST OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...MADE MINOR ADJUSTMENTS FOR THE NEXT SEVERAL DAYS. FOR
TODAY ADDED A SLIGHT CHANCE TO THE NORTHWEST COUNTIES WHERE LIKE
THE PAST FEW DAYS THE HRRR SHOWED AFTERNOON DEVELOPMENT.
TEMPERATURES OVERNIGHT REMAINED HIGH IN THE MID 70S...WHICH WILL
PROVIDE A WARM START FOR HEAT ADVISORY CONDITIONS LATER TODAY.
LOOK FOR SCATTERED CLOUDS DEVELOPING THIS AFTERNOON...BUT NOT
ENOUGH COVERAGE TO KEEP TEMPERATURES FROM RETURNING TO THE
LOWER 90S...AND IN SOME W SITES IN THE MID 90S. EXPECT SOME LOW
LEVEL WIND SHEAR TO STRENGTHEN TODAY WITH STRONGER SOUTHWEST WINDS
ALOFT. MIXING MAY CAUSE A DROP OF DEWPOINTS SLIGHTLY...BUT THE
MOISTURE BEING ADVECTED IN COULD COUNTER THIS AND EASILY SUPPORT
HEAT INDEX VALUES AROUND 100-104F THIS AFTERNOON. SOME WEAK
CONVERGENCE COULD BE ENOUGH TO TRIGGER SOME ISOLATED STORMS MAINLY
ACROSS OUR SOUTHERN TIER OF COUNTIES UP INTO NW PA. THE LAKESHORE
COUNTIES SHOULD REMAIN RAIN FREE FOR THE BETTER PART OF THE DAY.
THE CONVECTION IS EXPECTED TO GET GOING MID DAY NORTH IN MI AND CANADA
WHERE THE DYNAMICS WILL BE THE BEST. MODELS ARE INDICATING SOME
SUBSIDENCE OVER MOST OF OUR AREA THIS AFTERNOON WHICH COULD LEAVE
US WITH MOSTLY SUNNY SKIES EXCEPT THE MORE SOUTHERN COUNTIES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
ALL EYES WILL BE ON THE CONVECTION ANTICIPATED TO OUR NORTH AND
ANY OUTFLOWS THAT COULD SINK ACROSS THE LAKE AND TRIGGER STORMS
THIS EVENING IN OUR NORTHERN COUNTIES. EXCLUDING THAT
SCENARIO...THE BEST CHANCE FOR THUNDERSTORMS WON`T BE UNTIL 03-06Z
AS THE FRONT SINKS SOUTH INTO OUR AREA. THE BOTTLED UP ENERGY IN
PLACE OVER THE REGION WITH CAPES EXCEEDING 3K J/KG WILL BE REDUCED
MARGINALLY OVERNIGHT...BUT NOT ENOUGH TO RULE OUT STRONG TO SEVERE
STORMS. WITH UNIDIRECTIONAL WIND SHEAR...WITH A DECENT AMOUNT OF
SPEED SHEAR...THE HIGHEST THREAT WILL BE STRONG STRAIGHT LINE
WINDS. THE SLOW MOVING FRONT WILL PUSH INTO THE AREA DURING THE
EARLY MORNING HOURS ON SATURDAY. THIS WILL PROVIDE A FOCUS FOR
MORE CONVECTION ON SATURDAY...GRADUALLY CLEARING FROM NW TO SE
DURING THE AFTERNOON. SPC HAS THE REGION OUTLOOKED FOR SLIGHT RISK
OF SEVERE WEATHER FOR SATURDAY. THE STORM MOTIONS WILL BE
SUFFICIENT TO KEEP THE FLOOD RISK LIMITED TO ONLY AREAS WHERE
THERE MAY BE TRAINING. CONCERN HERE WILL BE WHERE THE FRONT OR
OTHER BOUNDARIES HANG UP...OTHERWISE THE HIGHEST QPF LOOKS TO BE
OVER NW PA. OVERALL LOOKING AT A 0.5" WIDESPREAD AVERAGE WITH
LOCALLY HIGHER AMOUNTS.
BEHIND FROPA A COOLER AND DRIER HIGH OUT OF CANADA WILL SLIDE IN
FOR SUNDAY GIVING A NICE BREAK TO THE HOT HUMID WEATHER OF THE
LAST WEEK. BY MONDAY AN UPPER LVL TROF WILL DEVELOP OVER THE OH
VALLEY AND WE`LL SEE A RETURN OF MUGGY CONDITIONS. TEMPERATURES
HOWEVER WILL REMAIN AT OR BELOW SEASONAL NORMALS AS THE
THICKNESSES DROP. THE PRESENCE OF THE TROUGH AND INCREASED
MOISTURE RETURN WILL UNFORTUNATELY PUT US BACK INTO A WETTER
PATTERN...THOUGH NOTHING ORGANIZED AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STILL PLENTY OF UNCERTAINTY IN THE FORECAST FOR TUESDAY THROUGH
THURSDAY AS PIECES OF JET ENERGY MOVE THROUGH A TROUGH THAT WILL BE
OVER THE GREAT LAKES REGION. FOR NOW HAVE SLIGHT CHANCE TO CHANCE
POPS IN THE FORECAST FOR MOST OF THE REGION.
TEMPERATURES TUESDAY THROUGH THURSDAY SHOULD BE VERY CLOSE TO
SEASONAL AVERAGES.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
PATCHY MORNING MVFR FOG HAS OCCURRED ONCE AGAIN FOR INLAND TAF
SITES BUT WILL QUICKLY BURN OFF. OTHERWISE THERE WILL BE VFR
CONDITIONS WITH AFTERNOON CUMULUS. SOUTHWESTERLY WINDS WILL BE
STRONGER TODAY WITH GUSTS AROUND 20 KNOTS LIKELY. THE STRONGEST
WINDS WILL LIKELY BE ACROSS NW OHIO INCLUDING KTOL AND KFDY WITH
GUSTS AROUND 25 KNOTS. CANT COMPLETELY RULE OUT SOME ISOLATED
CONVECTION OVER THE SOUTHERN TIER OF NY THAT MAY BUILD BACK INTO
PORTIONS OF NW PA AND SOUTH OF A LINE FROM KFDY TO KYNG.
WE WILL THEN AWAIT THE ARRIVAL OF THUNDERSTORMS AFTER SUNSET. MOST
OF THEM WILL LIKELY BE AFTER 03Z AND GRADUALLY SAG SOUTH AND EAST
WITH A COLD FRONT. SOME OF THESE STORMS WILL BE CAPABLE OF STRONG
WINDS.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG. SHOWERS AND
THUNDERSTORMS MAY ALSO CAUSE NON VFR CONDITIONS SATURDAY AND
TUESDAY.
&&
.MARINE...
A COLD FRONT WILL MOVE INTO THE UPPER GREAT LAKES TODAY AS HIGH
PRESSURE MOVES TO THE SOUTHEASTERN US. THIS WILL ALLOW A STRONGER
PRESSURE GRADIENT TO DEVELOP OVER THE LAKE TODAY. SOUTHWEST WINDS OF
10 TO 20 KNOTS SHOULD BE ENOUGH TO BUILD WAVES TO 3 TO 5 FEET FROM
WILLOWICK TO RIPLEY. THE LARGEST WAVES WILL LIKELY BE IN THE PA
WATERS. SO WITH THAT SAID WE WILL HOIST A SMALL CRAFT ADVISORY THAT
WILL REMAIN IN EFFECT THROUGH TONIGHT.
THE COLD FRONT WILL MOVE SOUTHEAST ACROSS LAKE ERIE ON SATURDAY.
HIGH PRESSURE WILL THEN BUILD ACROSS THE GREAT LAKES ON SUNDAY
BEFORE SHIFTING EAST AND STAYING NORTH OF LAKE ERIE ON MONDAY.
NORTHEAST WINDS WILL DEVELOP BY SUNDAY MORNING WITH CHOPPY
CONDITIONS POSSIBLE FOR THE WESTERN HALF OF THE LAKE. WINDS SHOULD
BECOME SOUTHERLY BY MONDAY AS WARM FRONT LIFTS ACROSS THE LAKE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM EDT THIS
EVENING FOR OHZ003-006>011-013-017>023-027>033-036>038-
047.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON/TK
SHORT TERM...JAMISON
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1119 AM EDT FRI JUL 19 2013
.SYNOPSIS...
THE SUBTROPICAL RIDGE OVER THE EASTERN UNITED STATES WILL BEGIN ITS
SLOW EROSION OVER THE NEXT 2 DAYS. A VIGOROUS NORTHERN STREAM WAVE
SHOULD LOWER THE 500 HPA HEIGHTS AND PUSH A COLD FRONT INTO THE
REGION SATURDAY. IT WILL BE UNSEASONABLY WARM UNTIL THE FRONTAL
PASSAGE AND THE FRONT COULD TRIGGER SOME STRONG THUNDERSTORMS. THE
500 HPA TROUGH SHOULD BUILD OVER THE REGION SUNDAY INTO NEXT WEEK.
IT WILL BE SIGNIFICANTLY COOLER AND DRIER SUNDAY AND INTO THE
COMING WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
14-15Z...VISIBLE SATL LOOPS SHOW CU FIELD GOING UP ALONG ON THE
WRN AND CNTRL RIDGES...PARALLEL TO THE LLVL FLOW INDICATING BLYR
DESTABILIZATION. 14Z RUC ML CAPES ARE RUNNING BTWN 2-2.5K J/KG PER
SPC MESO PAGE. LATEST OBS STILL SHOW SOME 6-7SM HZ WITH SFC
DEWPOINTS IN THE LOW 70S. TEMPS SHOULD REACH THE LOW 90S IN THE
LWR SUSQ VLY BY 15Z WITH HEAT INDEXES APPROACHING 100F.
THE MAIN FCST CHALLENGE FOR TODAY CONTINUES TO BE FOCUSED ON THE
DEVELOPMENT/PLACEMENT OF DIURNAL CONVECTION. WITH AFTN TEMPS IN
THE UPPER 80S TO MID 90S AND SFC DEWPTS BTWN 65-70F...CAPES WILL
BE ROBUST AND EASILY SUPPORT UPDRAFTS. QUESTION REMAINS AS TO THE
EVOLUTION OF STORMS GIVEN NEBULOUS FORCING AND WARM 700MB TEMPS.
RAPID-REFRESH MESO MDL DATA IS STILL SHOWING THE GREATEST CVRG OF
TSTMS IN WRN/SWRN PA INTO WV. THIS MAY BE DUE TO A WK SHORTWAVE
ROTATING FROM KY INTO THE UPPER OH VLY ON THE NW PERIPHERY OF
RETREATING UPPER RIDGE. THE TERRAIN WILL ALSO ACT TO ENHANCE
LIFT. SOME CONVECTION IS ALSO PSBL NEAR THE LAKESHORE BOUNDARY
OVER THE NW MTNS. OVERALL...EXPECT ISOLD TO WDLY SCT TSTMS AS WE
GET LATER IN THE DAY. THE ENVIRONMENT SHOULD FAVOR MAINLY NON-SVR
MULTI-CELL STORMS GIVEN HIGH CAPE AND RELATIVELY WEAK 0-6KM SHEAR.
A HEAT ADVISORY REMAINS IN EFFECT FOR THE S-CENTRAL MTNS AND SUSQ
VLY UNTL 8PM. HEAT INDEXES/APPARENT TEMPERATURES ARE FCST TO REACH
THE 100 TO 104F RANGE...RESULTING IN AN ELEVATED RISK OF HEAT-
RELATED ILLNESS ESPECIALLY THOSE WITHOUT AC OR OUTDOORS FOR AN
EXTENDED PERIOD.
AFTN/EVE STORMS SHOULD WEAKEN INTO TONIGHT WITH THE LOSS OF
HEATING. IT WILL BE A WARM HUMID/MUGGY OVERNIGHT WITH INCREASED
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL SYSTEM - WHICH
SHOULD REACH THE ST. LAWRENCE VLY AND LWR LKS REGIONS BY DAYBREAK
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE CLOUDS WITH THE FRONT SHOULD KEEP IT A BIT COOLER SATURDAY
ESPECIALLY IN THE NORTHWESTERN AREAS. THE STRONG SOUTHWESTERLY
FLOW...HIGH PRECIPITABLE WATER VALUES AND RELATIVELY HIGH CAPE
IMPLY THAT THERE SHOULD BE THUNDERSTORMS SATURDAY FROM LATE
MORNING IN THE WEST TO LATER AFTERNOON IN THE SOUTHEAST. SOME OF
THESE STORMS COULD BE STRONG TO SEVERE. NEARLY ALL OF OUR AREA IS
IN SLIGHT RISK FOR SEVERE THUNDERSTORMS SATURDAY. THERE IS SOME
MODESTLY STRONG MOISTURE FLUX AT 850 HPA IMPLYING GOOD LIFT MOVING
ACROSS THE STATE FROM ABOUT 15Z TO 00Z.
MOST MODELS IMPLY THE DEEP MOISTURE PLUME IS PUSHED TO OUR EAST
SATURDAY EVENING. DRIER AIR MOVES IN LATE EVENING WITH COOLER AIR
BEHIND IT. SHOULD BECOME QUITE COMFORTABLE OVERNIGHT AND NOTICEABLY
COOLER LOWS ON SUNDAY MORNING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
SUNDAY SHOULD BE A POST FRONTAL DAY WITH PW VALUES NEAR TO
SLIGHTLY BELOW NORMAL. THE LOWER TROPOSPHERIC TEMPERATURES WILL BE
NEAR NORMAL TOO. THE CHANCE TO SHOWERS SHOULD BE LOW PERHAPS BEST
CHANCE IN SOUTHERNMOST AREAS CLOSE TO THE FRONTAL BOUNDARY.
OVERALL...SUNDAY IS LOOKING LIKE A VERY PLEASANT DAY FOR MOST
AREAS AS A WEAK AREA OF HIGH PRESSURE WILL BE OVER THE REGION. THE
LOWER HUMIDITY AND LOWER TEMPERATURES SHOULD BE WELCOME RELIEF.
THE LOW-LEVEL FRONTAL BOUNDARY DOES NOT PUSH TOO FAR TO OUR SOUTH.
THUS AS ANOTHER WAVE APPROACHES FROM THE WEST IT WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS.
THE NORTHWESTERLY FLOW WILL LIKELY PUSH A FRONT THROUGH THE REGION
AROUND MID-WEEK. THIS COULD INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS...MOST LIKELY ON WEDNESDAY. BEHIND THIS SECOND FRONT THE PW
VALUES DROP TO BELOW NORMAL...SHOULD BE VERY COMFORTABLE THURSDAY
AND FRIDAY BEHIND THIS FRONT SHOULD THESE FORECAST PROVE CLOSE TO
CORRECT.
OVERALL...THE MODELS AND ENSEMBLES ALL SHOW A TROUGH OVER THE
EASTERN USA MOST OF THE COMING WEEK IMPLYING COOLER AND RELATIVELY
DRIER WEATHER. BY MID-WEEK THE HEAT WAVE OF MID-JULY 2013 SHOULD
BE A FAINT MEMORY.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR CUMULUS WILL CONTINUE TO BUILD THRU THE AFTN WITH VISBYS IN
THE 6-8SM RANGE IN HZ DUE TO VERY MOIST BLYR /DEWPOINTS IN THE
UPPER 60S TO LOW 70S/. INCREASING INSTABILITY SHOULD COMBINE WITH
THE TERRAIN TO PROMOTE ISOLD TO SCT TSTM ACTIVITY WITH INITIATION
IN THE 17-20Z TIMEFRAME. WILL CONTINUE TO SHOW VCTS AND CB/S IN
THE TAFS GIVEN UNCERTAINTY IN EXACT LOCATION OF STORMS.
W/SW LLVL FLOW AHEAD OF APPROACHING COLD FRONT SHOULD LIMIT FOG/ST
FORMATION LATE TONIGHT...ESPECIALLY OVER THE WRN AREAS. ERN TAFS
HAVE A BETTER SHOT A GOING CLR/CALM SO COULD SEE SOME LCL
RESTRICTIONS BY DAYBREAK SATURDAY. THE COLD FRONT WILL CROSS THE
REGION LATER SATURDAY AND TRIGGER SCT STG TO SVR STORMS. THE WND
SHIFT SHOULD OCCUR FROM NW-SE BY SAT NIGHT.
OUTLOOK...
SAT...VFR. PM TSTM IMPACTS. SOME STORMS MAY BE SVR.
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...GRUMM/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...GRUMM/MARTIN
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1051 AM CDT FRI JUL 19 2013
.UPDATE...THE LINE OF SHOWERS AND THUNDERSTORMS THAT WERE MOVING
THROUGH WEST CENTRAL AND CENTRAL WI...AND SOUTHEAST MN EARLIER
THIS MORNING HAVE ALL BUT DISSIPATED UPON MOVING SOUTHEAST INTO
THE CWA AS OF 10 AM CDT. VIS SAT SHOWS CONVECTIVE DEBRIS AND MID
LEVEL ACCAS ORIENTED SW TO NE MOVING SOUTHEAST THROUGH SOUTH
CENTRAL AND EAST CENTRAL WISCONSIN. UPSTREAM...DIURNAL CU ALREADY
DEVELOPING IN GRB AND MSP FORECAST AREAS.
MAIN CHANGES WERE LIMITED TO CURRENT TRENDS AND UPDATING THE
WX/POPS IN THE TODAY PERIOD. HIGHS LOOK ON TRACK AS IS. REGARDING
POPS/WX THIS AFTERNOON/EVENING...ECMWF AND NAM NOT PRODUCING MUCH
QPF WITH FROPA. HRRR AND LOCAL WRF FLAVOR PRODUCING ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WITH FROPA...BUT NOT LARGE
IN COVERAGE. ACTIVITY IS MAINLY SHOWN TO DEVELOP AFTER 20
UTC...WITH THE BULK OF THE ACTIVITY THE SOUTHEAST HALF OF THE CWA.
DESTABILIZATION SHOULD BE SUFFICIENT TODAY GIVEN CURRENT
CONDITIONS AND AFTER THESE CLOUDS MOVE THROUGH.
LOOKING AT THE NEAR STORM ENVIRONMENT THIS AFTERNOON AND EVENING
FROM THE RAP...DEEP LAYERED 0-6 KM SHEAR PEAKS AROUND 30-35
KTS...AMPLE ML CAPE INSTABILITY IS PRESENT...AND LOW-LEVEL
MOISTURE WILL BE FAVORABLE WITH SFC DEW POINTS IN THE LOW 70S. AS
SUCH...THE ENVIRONMENT STILL LOOKS SUPPORTIVE FOR MULTICELLS AND A
FEW SUPERCELLS PROVIDED THINGS GET UNDERWAY. SPC SSEO DOESNT
SHOW MUCH POTENTIAL IN REGARD TO SUPERCELLS THOUGH. ESPECIALLY
WHEN LOOKING AT THE UPDRAFT HELICITY IN TERMS OF A SIGNAL THIS
AFTERNOON/EVENING.
ET
&&
.AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED ACROSS TAF SITES
THIS AFTERNOON...TONIGHT AND SATURDAY. GUSTY SOUTHWEST TO WEST
WINDS ARE EXPECTED UNTIL SUNSET...WITH FREQUENT GUSTS IN THE 20 TO
25 KNOT RANGE. SOME DIURNAL CUMULUS WILL DEVELOP THIS AFTERNOON IN
THE WAKE OF THE MID LEVEL CLOUDS NOW MOVING THROUGH THE AREA.
SCATTERED SHOWERS AND STORMS ARE EXPECTED WITH THE COLD FRONTAL
PASSAGE LATER THIS AFTERNOON...ENDING EARLY THIS EVENING AS FRONT
MOVES OUT OF THE AREA. LEFT VICINITY THUNDER WORDING IN TAFS TO
ACCOUNT FOR THIS...WITH BRIEF MVFR VISIBILITIES AND GUSTY WINDS
POSSIBLE IN ANY STORMS.
WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT BY MID
EVENING...WITH SKIES CLEARING OUT TONIGHT WITH COOLER AND DRIER
AIRMASS MOVING IN. WINDS WILL SHIFT NORTH AND THEN NORTHEAST BY
SATURDAY AFTERNOON...AS BACKDOOR COLD FRONT MOVES SOUTHWEST
THROUGH THE AREA. MOSTLY CLEAR SKIES ARE EXPECTED SATURDAY.
WOOD
&&
.MARINE...SMALL CRAFT ADVISORY CONTINUES UNTIL 00Z SATURDAY FOR
ALL OF THE NEARSHORE WATERS. TIGHT PRESSURE GRADIENT AND DAYTIME
HEATING ALLOWING FOR GUSTY SOUTHWEST TO WEST WINDS ACROSS THE
WATERS. THESE WINDS WILL CONTINUE THROUGH THE REST OF THE
DAY...THUS HAVE EXTENDED SMALL CRAFT ADVISORY NORTH OF NORTH POINT
LIGHTHOUSE UNTIL 00Z SATURDAY. WAVES WILL REMAIN WELL BELOW SMALL
CRAFT ADVISORY CRITERIA WITH OFFSHORE FLOW. WINDS WILL THEN
SUBSIDE EARLY THIS EVENING WITH WEAKENING PRESSURE GRADIENT AND
PASSING COLD FRONT.
WOOD
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT FRI JUL 19 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
CURRENTLY WATCHING A LINE OF PRE-FRONTAL THUNDERSTORMS FROM
NORTHWEST WISCONSIN THROUGH SOUTH-CENTRAL MINNESOTA. SEEMS THESE
STORMS ARE HOLDING UP FAIRLY WELL RIGHT NOW...SO INCREASED MORNING
POPS A BIT IN THE NORTHWEST HALF OF THE FORECAST AREA. KIND OF A
TRICKY ONE THOUGH...BECAUSE MODELS ARE ALL DOING DIFFERENT THINGS
WITH THIS MORNING CONVECTION...FROM WIPING IT OUT BEFORE IT
ARRIVES...TO PUSHING IT ALL THE WAY THROUGH THE FORECAST AREA. THE
AMOUNT OF CLOUDS/PRECIP ACROSS SRN WI THIS MORNING WILL CERTAINLY
IMPACT HIGH TEMPS AND RESULTANT DESTABILIZATION FOR THE NEXT ROUND
OF STORMS AS THE COLD FRONT APPROACHES.
WENT WITH THE SOLUTION SEEN IN THE MOST MODELS...WHICH WOULD BRINGS
THE LINE OF STORMS IN...BUT WIPES IT OUT BY THE TIME IT REACHES THE
SOUTHEAST. THIS WOULD LEAVE A WINDOW OF OPPORTUNITY TO HEAT BACK UP
AHEAD OF THE FRONT. GIVEN SUFFICIENT SUNSHINE...MODELS SUGGEST
SURFACE BASED CAPES REACHING AROUND 3000 J/KG THIS AFTERNOON.
ALSO...0-6 KM BULK SHEAR WILL BE 30-35 KT. THE BEST 850 FLOW WILL BE
SET UP JUST TO THE SOUTH AND INTO MICHIGAN...ALONG WITH THE BETTER
UPPER DIVERGENCE. STILL...SEEMS LIKE A DECENT SETUP FOR STRONG TO
SEVERE STORMS IF THEY CAN GET GOING THIS AFTERNOON. THE NAM DOES
SHOW A BIT OF A CAP THROUGH MUCH OF THE AFTERNOON WHICH COULD BE AN
ISSUE. WENT WITH HIGH CHANCE POPS FOR THROUGH THE DAY DUE TO GENERAL
UNCERTAINTY. MAY NEED TO RAISE MORNING POPS IN AT LEAST THE
NORTHWEST THOUGH IF THE CONVECTION TO THE NORTHWEST CONTINUES TO
HOLD TOGETHER.
LOOKS LIKE ANOTHER HOT AND HUMID ONE TODAY AHEAD OF THE FRONT. GIVEN
MORNING CLOUDS AND CONVECTION AND THEN POSSIBLE REDEVELOPMENT THIS
AFTERNOON...WENT WITH HIGHS A COUPLE DEGREES LOWER THAN THE LAST
COUPLE DAYS. STILL LOOKS LIKE 95-100 DEGREE HEAT INDICIES
THOUGH...POSSIBLY A BIT OVER 100 IN A FEW SPOTS. WILL THUS KEEP HEAT
ADVISORY GOING INTO EARLY EVENING.
SHOULD TURN DRY BY LATE EVENING AS THE FRONT PUSHES THROUGH. SHOULD
SEE LOWS ACTUALLY FALL INTO THE 60S MOST PLACES OVERNIGHT AS COOLER
AND DRIER AIR BEGINS TO MOVE IN BEHIND THE FRONT.
SATURDAY...FORECAST CONFIDENCE HIGH.
A SECONDARY COLD FRONT WILL DROP DOWN THROUGH WI ON SATURDAY...WITH
WINDS BECOMING NORTH. THE MODELS SHOW THE FRONT ACCELERATING DOWN
THE LAKE A LITTLE FASTER THAN ON LAND AND PRODUCE LIGHT QPF ALONG
THE CONVERGENCE LINE IN SOUTHEAST WI. WILL CONTINUE DRY FORECAST FOR
NOW GIVEN THE WEAK FORCING.
WITH MORNING SUNSHINE AND THE COLD FRONT WEAKENING AS IT GETS INTO
SOUTH CENTRAL WI...HIGHS WILL BE IN THE LOWER 80S OVER MUCH OF THE
AREA. THE COOL SPOT IN THE UPPER 70S WILL BE THE SHEBOYGAN AREA
WHERE NORTH WINDS SHOULD PUSH INLAND EARLIER IN THE DAY. THIS WILL
BE A WELCOMED RELIEF TO THE HEAT WAVE.
SATURDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM.
LATER SATURDAY NIGHT...THE LOW LEVEL JET WILL POINT INTO WESTERN WI
ALONG WITH 850MB WARM AIR ADVECTION AND A SHORTWAVE TROUGH MOVING
ACROSS THE UPPER MIDWEST. THE ELEVATED THUNDERSTORM CHANCE WILL BE
HIGHER TOWARD EASTERN MN/WESTERN WI...BUT ADDED A SMALL CHANCE IN
THE WESTERN MKX FORECAST AREA.
THIS FAVORED AREA FOR THUNDERSTORMS IN THE VICINITY OF THE LOW LEVEL
JET AND THE SHORTWAVE TROUGH WILL SHIFT EASTWARD ACROSS WI THROUGH
THE DAY SUNDAY. THE NAM FOCUSES CONVECTION MORE IN NORTHERN WI ON
THE NOSE OF THE LLJ WHILE THE ECMWF DIMINISHES THAT CONVECTION.
THERE WILL BE ANOTHER AREA OF CONVECTION TIED MORE TOWARD THE BASE
OF THE SHORTWAVE TROUGH OVER IL. THERE IS A CHANCE THAT SOUTHERN WI
WILL END UP BETWEEN THE TWO AREAS OF CONVECTION.
THE ECMWF IS SLOWER WITH THE 500MB TROUGH CROSSING WI...SO CHANCE OF
THUNDERSTORMS CONTINUES THROUGH SUNDAY NIGHT.
EITHER WAY...EXPECT PLENTY OF CLOUDS SUNDAY. ALONG WITH 925MB TEMPS
ONLY AROUND 18C...HIGHS WILL BE IN THE UPPER 70S INLAND AND
LOWER/MID 70S NEAR THE LAKE WITH EAST WINDS.
LONG TERM...
MONDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM.
A 500MB NORTHWEST FLOW PATTERN SETS UP OVER THE UPPER MIDWEST FOR
THE FIRST HALF OF NEXT WEEK. WEAK SHORTWAVES WILL BRING THUNDERSTORM
CHANCES TO SOUTHERN WI ON MONDAY. THERE IS GENERALLY AGREEMENT
BETWEEN THE GFS AND ECMWF THAT A SURFACE LOW PRESSURE TROUGH WILL
SWEEP SOUTHEAST THROUGH WI MONDAY NIGHT INTO TUE MORNING WITH
THUNDERSTORM CHANCES ALONG THAT FRONT.
WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO LOW.
SURFACE HIGH PRESSURE IS EXPECTED OVER THE GREAT LAKES REGION ON
WEDNESDAY. THEN THE GFS BRINGS THUNDERSTORMS INTO SOUTHERN WI ONCE
AGAIN ON ANOTHER SHORTWAVE WHILE THE ECMWF KEEPS US HIGH AND DRY. IT
WILL DEPEND ON HOW AMPLIFIED THAT EASTERN UPPER TROUGH WILL BECOME.
AVIATION/12Z TAFS/...
WILL BE A CHANCE FOR SHOWERS AND STORMS TODAY AS A COLD FRONT MOVES
THROUGH THE FORECAST AREA. WILL PROBABLY SEE TWO ROUNDS...THE FIRST
OF WHICH WILL ARRIVE IN THE NORTHWEST THIS MORNING. SOME UNCERTAINTY
AS TO HOW WELL THIS WILL HOLD TOGETHER AS IT PROGRESSES SOUTHEAST.
SECOND ROUND WILL LIKELY FIRE RIGHT AHEAD OF THE FRONT BY LATE
AFTERNOON...WITH THE BEST CHANCE THEN ACROSS THE SOUTHEAST HALF OF
THE FORECAST AREA. SOME OF THE STORMS COULD BE STRONG TO SEVERE THIS
AFTERNOON INTO EARLY EVENING.
WILL THEN TURN DRY BY LATE EVENING...WITH QUIET WEATHER EXPECTED
OVERNIGHT AND INTO SATURDAY.
VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS...EXCEPT FOR
LOWER VSBYS POSSIBLE IN ANY MODERATE TO HEAVY RAINFALL.
MARINE...
SOUTHWEST WINDS WILL LIKELY REACH SMALL CRAFT ADVISORY LEVELS TODAY
AHEAD OF AN APPROACHING COLD FRONT. THE BEST CHANCE FOR HIGHER GUSTS
WILL BE ALONG SHORE FROM MID MORNING INTO LATE AFTERNOON NORTH AND
EARLY EVENING SOUTH. A SMALL CRAFT ADVISORY WILL THUS BE ISSUED THIS
MORNING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DDV
SATURDAY THROUGH THURSDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT FRI JUL 19 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE WESTERN U.S. AS WELL AS OVER THE
MID-ATLANTIC...WHILE TROUGHING WAS IN-BETWEEN FROM SOUTH CENTRAL
CANADA INTO WESTERN MN. THIS TROUGHING IS COMPOSED OF A POTENT
SHORTWAVE OVER MANITOBA...A SHORTWAVE FROM CENTRAL NORTH DAKOTA INTO
NORTHERN MN...AND A DEEP DRY-SLOT AHEAD OF THE SHORTWAVE FROM SOUTH
DAKOTA INTO WESTERN LAKE SUPERIOR. A COLD FRONT AT THE SURFACE WAS
ANALYZED FROM NEAR SIOUX FALLS TO THUNDER BAY ONTARIO...SLIGHTLY
AHEAD OF THE DRY SLOT. AMAZINGLY...DESPITE 4000 J/KG OF SBCAPE AND
LITTLE CIN ON THE 00Z ABR SOUNDING...THE FRONT WENT THROUGH THERE
WITH LITTLE ACTIVITY. BEST GUESS WAS THE LACK OF CONVERGENCE ON THE
FRONT...WHICH WAS REPRESENTED WELL ON 0-2KM RAP CONVERGENCE PLOTS.
FRONT IS MORE ACTIVE NOW...MORESO THE WARM ADVECTION AHEAD OF
IT...WITH HIGHER BASED SHOWERS AND THUNDERSTORMS FROM FARMINGTON MN
TO PARK FALLS WI. WARM AIR CONTINUES TO HOLD STRONG IN THE WARM
SECTOR WITH READINGS IN THE UPPER 70S / LOW 80S...THANKS IN PART TO
A 30-45 KT 925MB WINDS OVER THE AREA. THERE IS EVEN WARMER AIR
FLOWING IN FROM THE WEST ALONG THE FRONT...OBSERVED ON THE 00Z ABR
SOUNDING WITH AN 800MB TEMP OF 20C AND 925MB TEMP OF 30C...COMPARED
TO 17C AND 27C RESPECTIVELY FROM THE 00Z MPX SOUNDING. BEHIND THE
FRONT...925MB TEMPS ARE NOT THAT MUCH COOLER WITH 28C OBSERVED AT
GGW...BUT DEWPOINTS DROP INTO THE 50S AND LOW 60S.
SYNOPTIC OVERVIEW...
UPPER TROUGHING IS STILL POISED TO FORM OVER THE WESTERN GREAT LAKES
REGION BY 06Z TONIGHT...THOUGH THE MORE POTENT SHORTWAVE COMPOSING
THE TROUGH IS FORECAST TO STAY UP IN CANADA. MEANWHILE...THE
SHORTWAVE SEEN UP IN CENTRAL NORTH DAKOTA IS SLATED TO DROP INTO
CENTRAL MN BY 18Z...THEN PUSH EAST INTO LOWER MI. WITH THE UPPER
TROUGHING FORMING...EXPECT THE COLD FRONT TO CONTINUE MARCHING
SOUTHEAST. MODEL TIMING IS WELL AGREED UPON...AT 18Z STRETCHING FROM
OMAHA NEB TO VOLK FIELD WI AND MARINETTE WI...AND AT 00Z FROM
NORTHWEST MO TO NEAR DUBUQUE IA AND UP TO MANITOWOC WI.
HAZARDS...
ONGOING HEAT ADVISORY...DUE TO FRONTAL TIMING AND DRYING DEWPOINTS
BEHIND THE FRONT...HAVE CANCELLED SOME OF THE ADVISORY. AREAS
INCLUDE SOUTHEAST MN AND PORTIONS OF NORTHEAST IOWA INTO CENTRAL WI.
THERE ALSO IS A CHANCE FOR SEVERE WEATHER THIS AFTERNOON ALONG THE
COLD FRONT COMING THROUGH NORTHEAST IOWA AND SOUTHWEST WI. 0-6KM
SHEAR VALUES ARE HIGHER IN THE 09.00Z NAM...ORDER OF 30-40 KT VERSUS
20-30 KT IN THE 09.06Z RAP. IF SEVERE WEATHER OCCURS...DAMAGING
WINDS WOULD BE THE MAIN HAZARDS.
TODAY...
TWO BIG QUESTIONS...TEMPERATURES AND PRECIPITATION CHANCES. ON THE
PRECIPITATION SIDE OF THINGS...19.00Z GFS/NAM/REGIONAL CANADIAN ALL
WANT TO BRING THE SHOWERS AND SOME THUNDERSTORMS THROUGH THE
FORECAST AREA THIS MORNING PRIOR TO THE FRONTAL PASSAGE. THESE
ORIGINATE FROM ISENTROPIC LIFT ON THE 310 K SURFACE AHEAD OF THE
FRONT. IT APPEARS THESE SHOULD WEAKEN THROUGH THE MORNING TOO WITH
THE NOCTURNAL LOW LEVEL JET WEAKENING. A PERIOD OF CLEARING THEN
TAKES PLACE IN THE WARM SECTOR...WITH SOME HINTS FROM THE 19.00Z
GFS/REGIONAL CANADIAN AND 19.06Z RAP THAT THE FRONT COULD CONVECT IN
SOUTHEASTERN PORTION OF THE FORECAST AREA SAY BETWEEN 19-23Z. NOT
THRILLED ABOUT THE FRONT CONVECTING AS THE 0-2KM CONVERGENCE IS VERY
WEAK. HOWEVER...GIVEN MODELS HAVE BEEN SHOWING IT THE PAST FEW DAYS
AND PLENTY OF INSTABILITY PROGGED TO DEVELOP TODAY...KEPT SOME
CHANCES IN THE FORECAST. HAVE ALSO ADDED SOME LOW CHANCES OF
PRECIPITATION FOR THE AFTERNOON HOURS FROM TAYLOR COUNTY SOUTH TO
JACKSON. HERE ANOTHER FRONT LURKING UP IN NORTHERN MN IS PROGGED BY
THE 09.06Z RAP AND 09.05Z HRRR TO COME THROUGH AND HAVE SOME
CONVECTION ON IT. ON THE TEMPERATURE SIDE OF THINGS...A WARM START
PLUS 925MB TEMPS HOLDING IN THE 24-26C RANGE SHOULD EASILY ALLOWS
HIGHS TO REACH THE UPPER 80S TO POSSIBLY MID 90S AGAIN. THIS IS EVEN
DESPITE THE FRONTAL PASSAGE GIVEN THE WARM AIR STILL HOLDING BACK
AND LIKELY DEEPER MIXING BEHIND THE FRONT. HOWEVER...HEAT INDICES
WILL FALL WITH THE FRONT AS DRIER DEWPOINTS FLOW IN.
TONIGHT...
SUBSIDENCE AND DRYING COMING IN BEHIND THE COLD FRONT WILL ALLOW FOR
A MOSTLY CLEAR NIGHT ACROSS THE FORECAST AREA. DRIER AIR AND
DIMINISHING WINDS SHOULD ALLOW TEMPERATURES TO FALL CLOSE TO
GUIDANCE VALUES...IN THE UPPER 50S TO MID 60S...10-15 DEGREES COLDER
THAN TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM CDT FRI JUL 19 2013
SYNOPTIC OVERVIEW...
MUCH OF THE NEXT 6 DAYS LOOKS TO BE DOMINATED BY NORTHWEST FLOW
ACCORDING TO THE 19.00Z ECMWF/GFS/CANADIAN WITH RIDGING STAYING PUT
OVER THE WESTERN U.S.. THERE ARE SOME SIGNS FROM THE ECMWF THE RIDGE
MAY WANT TO BUILD EAST TOWARDS THE FORECAST AREA ON THURSDAY...BUT
PLENTY OF UNCERTAINTY ON THAT SEEING THE TROUGHING IN THE GFS.
ADDITIONALLY...THIS NORTHWEST FLOW HAS UNCERTAINTY IN TERMS OF
TIMING SHORTWAVES AND THE CHANCES OF PRECIPITATION WITH THEM.
SATURDAY THROUGH SUNDAY NIGHT...
MAIN FEATURE OF INTEREST DURING THIS PERIOD IS A SHORTWAVE ALL
MODELS HAVE TRACKING OUT OF MONTANA ON SATURDAY AND THROUGH THE
FORECAST AREA ON SUNDAY. SURPRISINGLY MODELS ARE IN REALLY GOOD
AGREEMENT WITH THIS SHORTWAVE...ALBEIT PERHAPS THE GFS HAS A BIT OF
CONVECTIVE FEEDBACK TO IT. IN ANY EVENT...INCREASING 310 K
ISENTROPIC LIFT COMBINED WITH INSTABILITY SHOULD INITIATE CONVECTION
OVER EASTERN SOUTH DAKOTA DURING THE AFTERNOON. THIS CONVECTION THEN
SPREADS TOWARDS THE FORECAST AREA SATURDAY NIGHT AS THE ISENTROPIC
LIFT AND 850MB MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE SHIFTS
EAST. PERHAPS THERE IS A SHOT SOME HIGH BASED SHOWERS COULD DEVELOP
DOWNSTREAM OF THE CONVECTION SATURDAY AFTERNOON...BUT THINK THE BULK
OF THE PRECIPITATION WOULD WAIT UNTIL SATURDAY NIGHT. SUNDAY APPEARS
TO HAVE THE HIGHEST CHANCE OF RAIN WHERE DPVA ACCOMPANYING THE
SHORTWAVE INTERSECTS 850MB MOISTURE TRANSPORT CONTINUING TO AIM AT
THE AREA. ITS HARD TO SAY HOW SUNDAY NIGHT WILL EVOLVE. SUBSIDENCE
BEHIND THE SHORTWAVE MOVING THROUGH ON SUNDAY WOULD SEEM TO LIKELY
PROVIDE A DRY PERIOD...LIKE SUGGESTED BY THE 19.00Z NAM. HOWEVER...
THE 19.00Z GFS/ECMWF SHOW A POTENT SHORTWAVE TROUGH CROSSING
SOUTHERN MANITOBA SUNDAY NIGHT...WHICH INCREASES 850MB MOISTURE
TRANSPORT INTO THE AREA. THEREFORE...THESE MODELS WANT TO HANG ONTO
SOME SHOWERS. HAVE MAINTAINED SOME CHANCES OF PRECIPITATION TO
ACCOUNT FOR THE GFS/ECMWF SCENARIO. BIGGEST ISSUE IN THE TEMPERATURE
DEPARTMENT IS HIGHS ON SUNDAY. IF IT RAINS ALL DAY...TEMPERATURES
MAY GET STUCK IN THE UPPER 60S/LOW 70S. FOR NOW TRENDED HIGHS DOWN
SLIGHTLY.
MONDAY THROUGH THURSDAY NIGHT...
THIS PERIOD IS HIGHLY UNCERTAIN. 19.00Z GFS/ECMWF/CANADIAN SHOW
NUMEROUS SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT THROUGH
MUCH OF THE WEEK. TIMING AND TRACK OF THESE VARIES FROM RUN TO
RUN...THUS THE LOW CONFIDENCE. THERE DOES APPEAR TO BE SOME SIGNAL
FOR A COLD FRONT COMING THROUGH THE FORECAST AREA MONDAY
NIGHT...ASSOCIATED WITH THAT POTENT TROUGH OVER SOUTHERN MANITOBA
PROGGED TO LIFT EAST-NORTHEAST. IF THIS STAYS CONSISENT...WE MIGHT
BE ABLE TO DRY OUT TUESDAY. OTHERWISE...HAVE MAINTAINED A MODEL
CONSENSUS OF 20-40 PERCENT CHANCES THROUGH THURSDAY NIGHT. LIKELY
THE ENTIRE PERIOD WILL NOT BE WET...BUT HARD TO PIN POINT MUCH FOR
POSSIBLE DRY PERIODS BEYOND TUESDAY. WITH A NORTHWEST FLOW IN
PLACE...EXPECT A COOLER FLOW OF AIR. 850MB TEMPS ARE GENERALLY
PROGGED TO DROP FROM 18-20C ON MONDAY TO 12-15C FOR TUESDAY THROUGH
THURSDAY. THESE SHOULD RESULT IN A DROP IN HIGHS TO SLIGHTLY BELOW
NORMAL AFTER NEAR NORMAL ON MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI JUL 19 2013
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY BRINGING
SCATTERED SHOWERS AND THUNDERSTORMS TO THE TAF SITES EARLY. THE
FRONT IS EXPECTED TO PUSH SOUTH OF THE TAF SITES BY EARLY THIS
AFTERNOON WITH WINDS SWITCHING TO THE NORTHWEST AND INCREASING TO
15 TO 18 KTS WITH GUSTS TO AROUND 25 KTS POSSIBLE. SOME OF THE
STORMS MAY PRODUCE BRIEF HEAVY DOWNPOURS AND GUSTY WINDS TO 45 KTS
THIS MORNING. WILL HAVE TO KEEP A VERY CLOSE WATCH FOR STORMS
REDEVELOPING ALONG THE FRONT LATE THIS MORNING INTO THIS
AFTERNOON. A FEW OF THESE STORMS COULD BECOME SEVERE WITH DAMAGING
WINDS. HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT PROVIDING
VFR CONDITIONS. SOME PATCHY FOG IS POSSIBLE TONIGHT...ESPECIALLY IN
VALLEY LOCATIONS.
&&
.CLIMATE...
ISSUED AT 321 AM CDT FRI JUL 19 2013
LA CROSSE WI HAS ONLY SEEN 0.27 INCHES FOR THE MONTH OF JULY
THROUGH THE 18TH. THIS IS THE 5TH DRIEST START TO JULY. THE DRIEST
THROUGH JULY 18TH WAS 0.05 INCHES BACK IN 1896...AND THE LAST TIME
IT WAS THIS DRY WAS IN 1967. FOR REFERENCE...LA CROSSE NORMALLY
SHOULD HAVE 2.41 INCHES UP THROUGH THE 18TH.
ROCHESTER MN HAS HAD QUITE A BIT MORE RAIN...THUS THE 1.42 INCHES
OBSERVED THROUGH JULY 18TH IS WELL OUTSIDE THE TOP 20 DRIEST.
STILL ROCHESTER IS 1.25 INCHES BELOW NORMAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...NONE.
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ011-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS PUEBLO CO
313 PM MDT FRI JUL 19 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
AN UPR RIDGE WL REMAIN CENTERED OVR NV TONIGHT AND SATURDAY. A UPR
DISTURBANCE WL CONTINUE MOVING SOUTH ACRS THE FORECAST AREA
TONIGHT. THERE IS PLENTY OF MOISTURE OVER THE AREA AS WELL. ALL
THE INGREDIENTS SEEM TO BE IN PLACE TO BRING WIDESPREAD PCPN OVR AND
NR THE MTS...WITH SCT ACTIVITY OVR THE SERN PLAINS. THE STEERING
FLOW WL REMAIN FAIRLY LIGHT...RESULTING AND SLOW MOVING STORMS AND
THUS UNDER THE HEAVIER STORMS...LOCALLY HEAVY RAIN COULD FALL. THIS
BECOMES A BIG CONCERN IF IT OCCURS OVR THE BURNS SCARS AS MUD AND
ASH FLOWS COULD OCCUR. WL LEAVE THE FLASH FLOOD WATCH IN EFFECT FOR
EL PASO AND TELLER COUNTIES. AS THE UPR DISTURBANCE MOVES SOUTHWARD
OVR THE AREA...BOTH THE RAP13 AND NAM SHOW THE FOCUS OF PCPN
SHIFTING SOUTHWARD THIS EVENING OVR THE SRN MTS AND SOUTH OF HIGHWAY
50. THE HRRR ALSO SHOWS WIDESPREAD PCPN AND CHANCES FOR RAIN OVR
SRN AREAS...BUT ALSO INCREASES PCPN CHANCES OVR EL PASO...TELLER
COUNTIES AND PUEBLO COUNTIES DURING THE EVENING HOURS.
OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NORTH
TO SOUTH...WITH SOME LIGHT PCPN POSSIBLY LINGERING THRU THE NIGHT
OVR FAR SOUTHERN AREAS. IT LOOKS DRIER IN THE UPR LEVELS ON SATURDAY
AS THE MSTR PLUME SHIFTS SOUTH OF THE AREA...BUT THERE WL STILL BE
PLENTY OF LOW LEVEL MSTR TO WORK WITH FOR SCT TO LIKELY POPS OVR THE
MTS AND PROBABLY ISOLD TO SCT POPS OVR THE SERN PLAINS. STORMS
SHOULD BE FAIRLY SLOW MOVING AGAIN AND WE COULD SEE SOME LOCALIZED
HEAVY RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
UPPER LEVEL FLOW TURNS SLIGHTLY MORE NORTHWESTERLY SUNDAY...WHICH
WILL TEND TO PUSH THE MOIST PLUME SOUTH OF THE STATE INTO NM AND
AZ BY AFTERNOON. MODELS SHOW WEAK FRONTAL BOUNDARY DISSIPATING
SOMEWHERE OVER THE ERN PLAINS OF CO...WITH DECREASING LOW LEVEL
MOISTURE AS UPSLOPE WINDS WEAKEN. SUSPECT TSRA WILL STAY ISOLATED
AND LIMITED TO MAINLY THE HIGHER TERRAIN SUN AFTERNOON AND
EVENING...AND WILL END QUICKLY BY LATE EVENING WITH LITTLE IN THE
WAY OF UPPER SUPPORT. MAX TEMPS SUN SHOULD CREEP UPWARD A DEGF OR
TWO...THOUGH 700 MB TEMPS SUGGEST RATHER HOT MET GUIDANCE MAXES
MAY BE JUST A TAD TOO WARM. SIMILAR SET-UP MON/TUE...AS WEAK
SURFACE FRONT REFORMS OVER NORTHEAST COLORADO AND AIR MASS OVER
SOUTHERN COLORADO CONTINUES TO DRY. AGAIN EXPECT ISOLATED
MOUNTAIN CONVECTION BOTH DAYS...THOUGH COVERAGE AND RAINFALL
AMOUNTS WILL BE RATHER SPARSE. 700 MB TEMPS CREEP UPWARD INTO THE
18C-20C RANGE...WHICH SHOULD PRODUCE A FEW 100F PLUS READINGS OVER
THE EASTERN PLAINS BOTH DAYS. ON WED...FRONT DROPS SOUTH OVER THE
PLAINS LEADING TO A RENEWED WESTWARD SURGE OF MOISTURE OVER THE
EASTERN MOUNTAINS AND PLAINS BY AFTERNOON. GFS AND ECMWF ARE
SIMILAR WITH SURFACE FEATURES...BUT ONLY GFS BREAKS OUT CONVECTION
THU EVENING...WHILE ECMWF STAYS DRY. WILL LEAN TOWARD THE WETTER
SOLUTION OF THE GFS FOR NOW...GIVEN THE DEEPER MOISTURE AND
INSTABILITY BEHIND THE FRONT. FARTHER WEST...LOW GRADE MONSOON
REDEVELOPS WED AS SLIGHTLY DEEPER MID LEVEL MOISTURE PUSHES BACK
INTO THE STATE...LEADING TO BETTER TSRA COVERAGE THAN MON/TUE.
PAST WED...MOISTURE LOOKS TO SLOSH BACK AND FORTH ACROSS THE
EASTERN PLAINS...WITH PERHAPS A DECREASE IN PRECIP CHANCES THU AND
AN INCREASE FRI. OVER THE MOUNTAINS...UPSWING IN CONVECTION LOOKS
POSSIBLE FRI AS WELL...ESPECIALLY AS LAST FEW MODEL RUNS OF BOTH
THE ECMWF AND GFS TRY TO BUILD THE UPPER RIDGE EASTWARD INTO
TX...ALLOWING A RENEWED INFLUX OF MOISTURE FROM THE SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 238 PM MDT FRI JUL 19 2013
THUNDERSTORMS WILL BE POSSIBLE THROUGH THIS EVENING AT KPUB...KCOS
AND KALS...PROBABLY ENDING BY 06Z...ALTHOUGH COULD CONTINUE A BIT
LATER AT KALS. HEAVY RAIN WILL BE POSSIBLE AT THE TAF SITES WHICH
COULD BRIEFLY CAUSE MVFR/IFR CONDITIONS. OTHERWISE VFR CONDITIONS
ARE EXPECTED. ON SATURDAY THE TAFS SITES COULD AGAIN SEE SOME
SHOWERS AND THUNDERSTORMS...MAINLY AFTER 20Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR COZ081-082-
084-085.
&&
$$
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
309 PM MDT FRI JUL 19 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 308 PM MDT FRI JUL 19 2013
SHOWERS AND THUNDERSTORMS DEVELOPING FIRST OVER THE CENTRAL AND
SOUTHERN MTNS THIS AFTERNOON ARE EXPECTED TO INCREASE IN COVERAGE AS
THE DAY WEARS ON AND INSTABILITY CONTINUES BEING REALIZED. A BIT
SLOWER START TODAY LIKELY THE RESULT OF MORE MORNING CLOUDINESS AS
COMPARED TO THURSDAY. THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR
ALL BUT THE NORTHERN-MOST COUNTIES...WHERE A BIT DRIER AIR WAS
WORKING IN. HOWEVER...THE HIGH-RESOLUTION HRRR MODEL AND THE NAM12
FOCUS PRECIPITATION MORE ON SE UT AND SW CO AND UP ACROSS GUNNISON
COUNTY THROUGH LATE EVENING. THIS SEEMS REASONABLE AS SATELLITE
IMAGES SHOW THE MONSOONAL MOISTURE PLUME AND ASSOCIATED
DEFORMATION ZONE LAYING OVER AND BECOMING MORE EAST-WEST ORIENTED
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. SEE HYDROLOGY
SECTION FOR ADDITIONAL INFO.
DRIER AIR WILL CONTINUE TO CIRCULATE AROUND HIGH PRESSURE CENTERED
OVER NEVADA ON SATURDAY. THE 12Z MODELS INDICATE PRECIPITABLE WATER
DROPS BELOW 0.50 INCH ACROSS OUR NORTH AND CENTRAL AREAS ON
SATURDAY...COMPARED TO 0.75 TO 1.30 VALUES FOR TODAY. THIS WILL
CONFINE SCATTERED SHOWERS AND THUNDERSTORMS TO SOUTH OF INTERSTATE
70 SATURDAY AFTERNOON. THE BEST COVERAGE WILL BE OVER THE SAN JUAN
MTNS WHERE PRECIPITABLE WATER VALUES OF OF 0.70 OR 0.80 INCH WILL
PERSIST. CONVECTION SHOULD DIE OUT BEFORE MIDNIGHT WITH THE LOSS OF
HEATING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 308 PM MDT FRI JUL 19 2013
WARMER AND DRIER THROUGH TUESDAY THEN A RETURN OF MONSOONAL MOISTURE
BEGINNING WEDNESDAY.
GOOD MODEL AGREEMENT CONTINUES. INTO EARLY NEXT WEEK THE UPPER
HIGH REMAINS CENTERED OVER THE GREAT BASIN AND NORTHERN
CALIFORNIA...WITH AN INVERTED TROUGH IN NORTHERN BAJA. A N-NW FLOW
KEEPS DRIER AIR ACROSS DOWN TO NEAR THE FOUR CORNERS ON SUNDAY.
MODELED PRECIPITABLE WATER VALUES ARE AT OR LESS THEN 0.5 INCH FOR
MUCH OF THE CWA WITH A SHARP INCREASED GRADIENT ALONG THE NM/AZ
BORDER. SO SCATTERED SHOWERS AND STORMS WILL FAVOR THE FAR SOUTH
AND ALONG THE SOUTHERN PORTION OF THE CONTINENTAL DIVIDE.
THIS DRIER AIR REMAINS IN PLACE THROUGH TUESDAY. DIURNAL
TEMPERATURE SPREAD WILL INCREASE IN THE DRIER AIR MASS WITH THE
LOWER VALLEYS OF UTAH AND FAR WESTERN COLORADO THREATENING TRIPLE
DIGIT AFTERNOONS AGAIN. DEWPOINTS IN THE 20-30S ALONG AND NORTH OF
I-70 WILL HELP EVAPORATIVE COOLERS TO WORK MORE EFFICIENTLY.
WEDNESDAY...THERE IS GOOD MODEL AGREEMENT THAT THE UPPER HIGH BEGINS
TO SHIFT TO SOUTH CENTRAL COLORADO...THEN ONTO THE SOUTHERN PLAINS
ON THURSDAY AND FRIDAY. MEANWHILE THE NORTHERN BAJA LOW BEGINS TO
LIFT NE INTO THE GREAT BASIN BRINGING SUBTROPICAL MOISTURE WITH IT.
THIS DEEPER MOISTURE AND INCREASED THUNDERSTORM POTENTIAL IS
CURRENTLY TIMED TO SPREAD INTO EASTERN UTAH WEDNESDAY IN THE FASTER
EC THEN WESTERN COLORADO ON THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 308 PM MDT FRI JUL 19 2013
SIMILAR TO YESTERDAY...SCATTERED SHOWERS AND THUNDERSTORMS MAINLY
ACROSS THE CENTRAL AND SOUTH LATE TONIGHT WILL BECOME MORE NUMEROUS
BY 00Z BEFORE DECREASING IN COVERAGE BY 06Z. HEAVY RAIN FROM THE
STRONGER STORMS WILL CREATE PERIODS OF MVFR OR EVEN IFR VISIBILITY
AT TIMES...WITH MOUNTAIN OBSCURATIONS. KVEL IS THE TAF SITE LEAST
LIKELY TO BE AFFECTED.
DRIER AIR WORKS IN FROM THE NW LATE TONIGHT AND SATURDAY CONFINING
CONVECTIVE ACTIVITY MAINLY SOUTH OF I-70 AFTER 18Z SATURDAY. VFR SHOULD
BE THE PREVAILING FLIGHT CONDITION AT ALL TAF SITES ON SATURDAY.
&&
.HYDROLOGY...
ISSUED AT 308 PM MDT FRI JUL 19 2013
THE FLASH FLOOD WATCH CONTINUES FOR MUCH OF THE FORECAST AREA. WILL
BE MONITORING STORMS CLOSELY ONCE THEY DEVELOP FOR THE POTENTIAL OF
EXCESSIVE RAINFALL/RUNOFF. SOME AREAS THAT MAY BE MORE PRONE TO
RUNOFF PROBLEMS WILL BE THOSE LOCATIONS THAT HAVE ALREADY RECEIVED
HEAVIER RAIN. BURN SCARS WILL LITTLE OR NO REGROWTH WILL BE
ESPECIALLY SUSCEPTIBLE TO ASH AND DEBRIS/MUD FLOW IN HEAVY RAIN. THE
THREAT OF HEAVY RAIN AND FLASH FLOODING DECREASES THIS WEEKEND.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ001>003-
006>014-017>023.
UT...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR UTZ022-025-
027>029.
&&
$$
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...JAD
HYDROLOGY...JAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1008 AM MDT FRI JUL 19 2013
.UPDATE...ONLY MINOR ADJUSTMENTS AT THIS TIME. SHOWERS AND TSTMS
OVER THE NORTHEAST PLAINS THIS MORNING WILL PERSIST INTO THE EARLY
AFTERNOON....WITH SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE
MOUNTAINS AND FOOTHILLS AROUND 18Z. HRRR RUNS OFFERING DIFFERING
SOLUTIONS REGARDING THE COVERAGE AND INTENSITY OF THE STORMS OVER
THE FOOTHILLS THIS AFTERNOON SO WILL NOT CHANGE ANY ANYTHING
REGARDING THE FLASH FLOOD WATCH AT THIS TIME. SINCE THE BURN AREAS
ALREADY GOT A GOOD DOSE OF RAINFALL YESTERDAY...THAT REASON ALONE
WILL JUSTIFY THE WATCH. SOME SOLUTIONS SUPPORT THE FLASH FLOOD
WATCH WHILE OTHERS ARE DRIER. HARD TO SAY AT THIS POINT...SO WILL
JUST HAVE TO MONITOR HOW THINGS DEVELOP.
&&
.AVIATION...SFC WINDS BECOMING NNELY AT THIS TIME SO TREND IN THE
WIND FCST STILL LOOKS ON TRACK. NO CHANGE REGARDING THE TIMING OF
TSTMS THIS AFTN AND EVENING AT THIS TIME. IF HEAVY RAIN DEVELOPS
WITH TSTMS THEN BRIEF MVFR CIGS/VSBYS WILL BE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 317 AM MDT FRI JUL 19 2013/
SHORT TERM...WATER VAPOR LOOP SHOWS UPPER LEVEL MOISTURE PLUME
SHIFTING VERY SLOWLY SOUTHWARD ACROSS THE FORECAST AREA EARLY THIS
MORNING. MEANWHILE...LAST NIGHTS PERSISTENT CONVECTION HAS LEFT
BEHIND A MESOSCALE CONVECTIVE VORTEX...OR MCV...OVER NORTHERN
WELD COUNTY... CREEPING EASTWARD. MCVS ARE QUITE RARE AROUND
HERE...BUT CAN SERVE TO SPARK CONVECTION ON THE DOWNSHEAR...OR
SOUTH/SOUTHEAST SIDE IN THIS CASE. HARD TO SAY EXACTLY WHERE THIS
FEATURE WILL BE BY THE TIME WE REACH CONVECTIVE TEMPS...BUT SHOULD
BE SOMEWHERE IN NORTHEAST COLORADO.
OTHERWISE...AS THE WATER VAPOR PLUME CONTINUES TO SHIFT SOUTHWARD
THIS WILL BRING A BETTER CHANCE OF STORMS TO THE DENVER METRO
AREA/I-70 CORRIDOR/POINTS SOUTHWARD THIS AFTERNOON. WE COULD SEE A
FEW SHOWERS LINGER THIS MORNING AS WELL...BUT CONVECTIVE STORMS
WILL LIKELY INITIATE IN/NEAR THE FRONT RANGE AND DOWNSHEAR SIDE OF
THE MCV BY LATE MORNING/NOON HOUR AS CONVECTIVE TEMPS ARE
REACHED. POTENTIAL FOR HEAVY RAIN WILL BE THERE ESPECIALLY WITH
THE HIGHEST PRECIPITABLE WATER PLUME SHIFTING SOUTHWARD TODAY.
WHILE THE NORTHERN PORTIONS COULD SEE SOME DRYING AND EVEN
SUBSIDENCE ON THE UPSHEAR SIDE OF THE MCV...ENOUGH FACTORS
MENTIONED IN HYDROLOGY SECTION BELOW TO WARRANT A FLASH FLOOD
WATCH FOR THE FOOTHILLS WITH MAIN THREAT ONCE AGAIN FOR THE BURN
SCARS. COULD SEE RAINFALL RATES OF 1-1.5 INCHES IN 45 MINUTES
FROM THE STRONGEST STORMS. EXPECT THINGS TO WIND DOWN FAIRLY
QUICKLY THIS EVENING WITH SOME DRYING NOTED MOVING IN FROM THE
NORTH/NORTHWEST.
LONG TERM...A SLIGHT INCREASE IN NORTHWESTERLY FLOW ALOFT IS
EXPECTED SATURDAY ALONG WITH A THETA E RIDGE ACROSS EASTERN
COLORADO. CAPE VALUES OF BETWEEN 1000-1500 J/KG WILL BE FOUND OVER
FAR NORTHEASTERN COLORADO. THIS WILL ALL COMBINE TO BRING A SLIGHT
CHANCE OF SEVERE STRENGTH STORMS OVER THIS AREA.
ELSEWHERE...ENOUGH MOISTURE WILL BE AROUND TO ALLOW FOR ISOLATED
TO SCATTERED THUNDERSTORM ACTIVITY. MOISTURE WILL BE ON THE
DECREASE OVER TODAY HOWEVER...SO FLOODING CONCERNS ARE A LOT LESS.
TEMPERATURES WILL BE WARMING A FEW DEGREES AS THE UPPER HIGH OVER
NEVADA CIRCULATES WARMER AIR AROUND INTO THE STATE.
SUNDAY THROUGH THURSDAY WILL FEATURE THE UPPER HIGH OVER NEVADA TO
BEGIN TO MIGRATE BACK EAST. THIS WILL BRING AN OVERALL WARMING
PATTERN. SUNDAY AND MONDAY WILL BE MOSTLY DRY EXCEPT A FEW
POSSIBLE STORMS OVER THE HIGH COUNTRY. THEN A WEAK SHORTWAVE
COMING DOWN OUT OF THE NORTHERN ROCKIES MAY PUSH A COOL FRONT
DOWN THE LEE SIDE OF THE ROCKIES TO BRING A BRIEF RESPITE FROM THE
WARM AND DRY PATTERN. HOWEVER...MODELS DISAGREEING IF THIS FRONT
WILL MAKE IT INTO CO...FOR NOW WILL TREND THE FORECAST TO BRING IT
IN WITH COOLER TEMPS AND SLIGHT CHANCE OF STORMS FOR THE PLAINS
ON TUESDAY AND AREA WIDE WEDNESDAY.
FOR THURSDAY...IT LOOKS LIKE THE UPPER LOW WHICH RETROGRADED FROM
WEST VIRGINIA ALL THE WAY TO ITS CURRENT POSITION OVER SONORA,
MEXICO WILL CONTINUE ITS PATH WEST...THEN GET PULLED NORTH AROUND
THE UPPER HIGH. THEN ITS PROGGED TO MOVE EAST ONSHORE AND BRING
MORE MOISTURE OUR WAY FOR THURSDAY. HAVE POPS ACROSS THE FORECAST
AREA TO ACCOUNT FOR THIS.
AVIATION...STORM THREAT IS A LITTLE HIGHER TODAY GIVEN THE ABOVE
MENTIONED FACTORS SO WILL LIKELY NEED TEMPO TSRA AND GUSTY VRB
WINDS TO 35 KTS FOR A FEW HOURS THIS AFTERNOON. MAIN THREAT SHOULD
BE 20Z-01Z WITH STORMS SHIFTING SOUTH OF THE FRONT RANGE AIRPORTS
01Z-04Z. BRIEF IFR/MVFR CONDITIONS POSSIBLE WITH THE STRONGEST
STORMS. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT.
HYDROLOGY...LOWER LIFTING CONDENSATION LEVELS AND RESULTANT
DEEPER WARM CLOUD DEPTH NEAR 1500 METERS MEANS MORE EFFICIENT
RAINERS POSSIBLE TODAY. AS A RESULT...HAVE OPTED FOR A FLASH FLOOD
WATCH FOR THE FRONT RANGE FOOTHILLS WITH MAIN THREAT OF FLASH
FLOODING ONCE AGAIN FOR THE BURN SCARS. COULD SEE RAINFALL RATES
OF 1-1.5 INCHES IN 45 MINUTES FROM THE STRONGEST STORMS. EXPECT
THINGS TO WIND DOWN BY 7-8 PM THIS EVENING WITH SOME DRYING NOTED
MOVING IN FROM THE NORTH/NORTHWEST. THERE IS A CHANCE OF
SUBSIDENCE AND DRYING MOVING IN A LITTLE EARLIER FOR THE NORTHERN
FRONT RANGE BURN SCARS INCLUDING HIGH PARK AND FOURMILE...BUT
STILL ENOUGH THREAT ESPECIALLY CONSIDERING RAINFALL YESTERDAY AND
ANTECEDENT CONDITIONS TO WARRANT A WATCH AT THIS TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM MDT THIS EVENING FOR COZ035-036.
&&
$$
SHORT TERM...COOPER
LONG TERM....D-L
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
334 PM EDT FRI JUL 19 2013
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS CU FIELD CONTINUING TO DEVELOP ACROSS
THE REGION THIS AFTERNOON. SCATTERED SHOWERS ACROSS NORTH AND SOUTH
GA HAVE DEVELOPED OVER THE LAST FEW HOURS AND SHOULD CONTINUE
THROUGH TONIGHT. THE MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM
WITH THE GFS AND ECMWF SHOWING A NICE SLUG OF TROPICAL MOISTURE
MOVING NORTHWARD OUT OF THE GULF TONIGHT. THIS MOISTURE IS EXPECTED
TO MOVE SLOWLY NORTHWARD AND SHOULD BE ACROSS OUR AREA THOUGH THE
WEEKEND. THE MAIN UPPER LEVEL LOW OVER THE GULF WILL FINALLY OPEN
INTO A SHORT WAVE TROUGH BY SATURDAY AFTERNOON PUTTING GA IN GOOD
SOUTHWEST FLOW. THIS WILL ALSO HELP TO ENHANCE THE SHRA/TSRA
PROBABILITY ACROSS THE STATE. THIS INCREASED MOISTURE IS NOT
EXPECTED TO BRING RAIN ACROSS THE AREA FOR WEEKS ON END LIKE WE
EXPERIENCED IN MID JUNE THROUGH THE BEGINNING OF JULY. THE PATTERN
WE ARE IN IS A MORE SUMMER LIKE PATTERN WITH DIURNALLY DRIVEN
INSTABILITY AND CONVECTION SO ANYTHING THAT DOES DEVELOP THIS
AFTERNOON AND SATURDAY AFTERNOON SHOULD DIMINISH AFTER SUNSET.
01
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MODELS ARE IN GOOD AGREEMENT WITH PEGGING BETTER PRECIP ACROSS
NORTH GEORGIA ON SUNDAY SO WENT AHEAD AND INTRODUCED LIKELY TO
THAT AREA. OTHERWISE ONLY MINOR TWEAKS TO THE EXTENDED AND THE
PREVIOUS DISCUSSION FOLLOWS.
11
LONG TERM /SATURDAY THROUGH THURSDAY/...
/ISSUED AT 349 AM EDT FRI JUL 19 2013/
MEDIUM RANGE MODELS START OUT QUITE SIMILAR TO BEGIN THE EXTENDED
FORECAST PERIOD WITH A BROAD WEAKNESS IN THE UPPER FLOW OVER THE
REGION THROUGH THE WEEKEND AS WEAK UPPER TROUGHING TAKES SHAPE ACROSS
THE EASTERN U.S. THROUGH EARLY NEXT WEEK. THERE IS SOME MODEL
DIVERGENCE IN THE EXACT PLACEMENT AND STRENGTH OF THE EASTERN U.S.
UPPER TROUGH BY THE LATTER HALF OF NEXT WEEK...BUT BOTH THE GFS AND
ECMWF MAINTAIN THIS FEATURE THROUGH THE PERIOD. SURFACE FEATURES SHOW
SIMILAR SLIGHT DEPARTURES BETWEEN THE MODELS...BUT THE GENERAL THEME
AMONG THE MEDIUM RANGE MODELS IS FOR GEORGIA TO BE ON THE NORTHWEST
SIDE OF THE WESTERN ATLANTIC RIDGE WITH PERSISTENT WEAK TROUGHING IN
THE LEE OF THE APPALACHIANS EXTENDING SOUTHWEST INTO THE FORECAST
AREA. THIS SHOULD PROVIDE AMPLE MOISTURE OVER THE REGION FOR AT LEAST
SCATTERED CONVECTION THROUGH THE PERIOD...WITH A NORMAL SUMMERTIME
DIURNAL BIAS. ANY WEAK RIPPLES MOVING THROUGH THE UPPER FLOW WILL
ENHANCE CONVECTIVE CHANCES...BUT TIMING OF ANY SUCH FEATURES ARE
PROBLEMATIC AT BEST IN THE EXTENDED FORECAST PERIOD AND WITH THE LACK
OF ANY CONSENSUS BETWEEN THE MODELS CONCERNING ANY LARGER...MORE
ORGANIZED WAVES I HAVE CHOSEN TO KEEP POPS BELOW LIKELY THROUGH THE
PERIOD.
20
&&
.AVIATION...
8Z UPDATE...
SATELLITE LOOP SHOWS CU FIELD DEVELOPING ACROSS THE REGION THIS
AFTERNOON WITH SOME ISOLATED SHOWERS NORTH AND SOUTH OF THE TAF
SITES. SO FAR THE PRECIP HAS STAYED AWAY FROM THE TAF SITES BUT
THE HRRR SHOWS A CLUSTER OF SHRA/TSRA DEVELOPING JUST WEST OF ATL
BY 00Z. WILL KEEP THE TEMPO GROUP IN FROM 21 TO 01 TO COVER THIS
AND WILL HAVE TO KEEP AN EYE ON THE SITUATION. WINDS ARE MAINLY
6KT OR LESS OUT OF THE SW BUT AM SEEING SOME SE WINDS AT TIMES.
CEILINGS AND VSBYS SHOULD STAY VFR THROUGH THE PERIOD EXCEPT IN
AND AROUND SHRA/TSRA DEVELOPMENT.
//ATL CONFIDENCE...18Z UPDATE...
CONFIDENCE MEDIUM TO HIGH ON ALL ELEMENTS
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 88 72 87 / 20 50 50 50
ATLANTA 72 87 73 85 / 20 60 60 50
BLAIRSVILLE 68 84 67 81 / 20 50 50 60
CARTERSVILLE 70 89 70 86 / 20 50 50 50
COLUMBUS 73 89 73 89 / 30 60 60 50
GAINESVILLE 72 87 72 84 / 20 50 50 50
MACON 72 89 72 89 / 30 60 60 50
ROME 70 89 70 87 / 20 50 50 50
PEACHTREE CITY 71 87 71 86 / 20 60 60 50
VIDALIA 72 89 73 89 / 40 60 60 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....11
AVIATION...01
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
156 PM EDT FRI JUL 19 2013
.PREV DISCUSSION... /ISSUED 727 AM EDT FRI JUL 19 2013/
SHORT TERM /TODAY THROUGH TONIGHT/...
/ISSUED AT 349 AM EDT FRI JUL 19 2013/
FOR THIS MORNING...SCATTERED SHOWERS HAVE MOVED OFF THE ATLANTIC AND
INTO SOUTHEAST GA. SOME OF THESE WILL MOVE INTO THE SOUTHEAST CORNER
OF THE CWA EARLY THIS MORNING AND SPREAD WESTWARD ACROSS THE REST OF
CENTRAL GA THIS MORNING. DAYTIME HEATING WILL AID IN CONVECTION THIS
AFTERNOON WITH THE BEST RISK IN THE MOUNTAINS AND ALSO CENTRAL GA.
LATEST MODELS SHOW THE SURGE OF MOISTURE EXPECTED FOR TODAY IS
COMING IN MUCH SLOWER THAN PREVIOUS RUNS...BRINGING IT INTO THE CWA
SATURDAY AFTERNOON. THE H5 LOW WILL FINALLY OPEN INTO A SHORT WAVE
TROUGH BY SATURDAY AFTERNOON AND THIS WILL PUT THE CWA IN A
SOUTHWEST FLOW. BOTH GFS/NAM INDICATE A SIGNIFICANT SHORT WAVE
MOVING INTO THE CWA SATURDAY AFTERNOON AND THIS SHOULD BRING
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
17
LONG TERM /SATURDAY THROUGH THURSDAY/...
/ISSUED AT 349 AM EDT FRI JUL 19 2013/
MEDIUM RANGE MODELS START OUT QUITE SIMILAR TO BEGIN THE EXTENDED
FORECAST PERIOD WITH A BROAD WEAKNESS IN THE UPPER FLOW OVER THE
REGION THROUGH THE WEEKEND AS WEAK UPPER TROUGHING TAKES SHAPE ACROSS
THE EASTERN U.S. THROUGH EARLY NEXT WEEK. THERE IS SOME MODEL
DIVERGENCE IN THE EXACT PLACEMENT AND STRENGTH OF THE EASTERN U.S.
UPPER TROUGH BY THE LATTER HALF OF NEXT WEEK...BUT BOTH THE GFS AND
ECMWF MAINTAIN THIS FEATURE THROUGH THE PERIOD. SURFACE FEATURES SHOW
SIMILAR SLIGHT DEPARTURES BETWEEN THE MODELS...BUT THE GENERAL THEME
AMONG THE MEDIUM RANGE MODELS IS FOR GEORGIA TO BE ON THE NORTHWEST
SIDE OF THE WESTERN ATLANTIC RIDGE WITH PERSISTENT WEAK TROUGHING IN
THE LEE OF THE APPALACHIANS EXTENDING SOUTHWEST INTO THE FORECAST
AREA. THIS SHOULD PROVIDE AMPLE MOISTURE OVER THE REGION FOR AT LEAST
SCATTERED CONVECTION THROUGH THE PERIOD...WITH A NORMAL SUMMERTIME
DIURNAL BIAS. ANY WEAK RIPPLES MOVING THROUGH THE UPPER FLOW WILL
ENHANCE CONVECTIVE CHANCES...BUT TIMING OF ANY SUCH FEATURES ARE
PROBLEMATIC AT BEST IN THE EXTENDED FORECAST PERIOD AND WITH THE LACK
OF ANY CONSENSUS BETWEEN THE MODELS CONCERNING ANY LARGER...MORE
ORGANIZED WAVES I HAVE CHOSEN TO KEEP POPS BELOW LIKELY THROUGH THE
PERIOD.
20
&&
.AVIATION...
18Z UPDATE...
SATELLITE LOOP SHOWS CU FIELD DEVELOPING ACROSS THE REGION THIS
AFTERNOON WITH SOME ISOLATED SHOWERS NORTH AND SOUTH OF THE TAF
SITES. SO FAR THE PRECIP HAS STAYED AWAY FROM THE TAF SITES BUT
THE HRRR SHOWS A CLUSTER OF SHRA/TSRA DEVELOPING JUST WEST OF ATL
BY 00Z. WILL KEEP THE TEMPO GROUP IN FROM 21 TO 01 TO COVER THIS
AND WILL HAVE TO KEEP AN EYE ON THE SITUATION. WINDS ARE MAINLY
6KT OR LESS OUT OF THE SW BUT AM SEEING SOME SE WINDS AT TIMES.
CEILINGS AND VSBYS SHOULD STAY VFR THROUGH THE PERIOD EXCEPT IN AND
AROUND SHRA/TSRA DEVELOPMENT.
//ATL CONFIDENCE...18Z UPDATE...
CONFIDENCE MEDIUM TO HIGH ON ALL ELEMENTS
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 71 88 72 / 20 20 50 50
ATLANTA 90 72 87 73 / 20 20 60 60
BLAIRSVILLE 87 68 84 67 / 30 20 50 50
CARTERSVILLE 91 70 89 70 / 20 20 50 50
COLUMBUS 94 73 89 73 / 40 30 60 60
GAINESVILLE 88 72 87 72 / 20 20 50 50
MACON 92 72 89 72 / 40 30 60 60
ROME 91 70 89 70 / 20 20 50 50
PEACHTREE CITY 89 71 87 71 / 20 20 60 60
VIDALIA 91 72 89 73 / 50 40 60 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....11
AVIATION...01
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
552 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...540 PM...
ISOLATED CONVECTION IS DEVELOPING ALONG THE COOL FRONT AND A
SUBTLE PRE-FRONTAL WIND CONVERGENCE FROM CENTRAL WI INTO
SOUTHEAST IA LATE THIS AFTERNOON. THIS NOW LOOKS TO BE THE ONLY
FOCUS FOR STORM ACTIVITY WITH THE REST OF THE CU HAVING
DISSIPATED ACROSS THE REGION.
THE COOL FRONT IS WELL-DEFINED ON OBSERVATIONS AND SATELLITE AND
EASING ITS WAY SOUTHEAST AT 15 KT. WATER VAPOR AND PROFILERS
INDICATE GRADUALLY INCREASE UPPER TO MID-LEVEL FLOW IS SETTLING
SOUTH ACROSS THE UPPER MISSISSIPPI VALLEY ASSOCIATED WITH THE
UPPER TROUGH. THIS MAY BE PROVIDING SOME BROAD ASCENT TO HELP
CONVECTION TO DEVELOP AS WELL.
THE MAIN PRESSURE RISES AND MOMENTUM BEHIND THE FRONT IS SHIFTING
MORE EAST THAN SOUTH ACROSS WI AND THUS IT CONTINUES TO BE
CONCERNING JUST HOW SHARP CONVERGENCE WILL OR WILL NOT BE THROUGH
THE EVENING AS THE FRONT APPROACHES AND MOVES INTO THE FORECAST
AREA. ALSO...THE FRONT IS NOW GOING AGAINST THE DIURNAL GRAIN AND
MOST OF THE LOW-LEVEL JET AND MOISTURE TRANSPORT FOCUS IS TO THE
NORTHEAST OF THE FORECAST AREA. SO THIS POINTS TOWARD SCATTERED
CONVECTION ONLY...MAYBE AT BEST...WITH THE FRONTAL PASSAGE. ANY
STORMS THAT DEVELOP WILL STILL HAVE PLENTY OF INSTABILITY WITH
SFC BASED CAPE ON RAP AND LAPS OF 2000 TO 3000 J/KG AND ASSOCIATED
LARGE VALUES OF DOWNDRAFT CAPE. THUS STORMS COULD FESTER/DEVELOP
ON OUTFLOWS AHEAD OF THE FRONT IF ANY CAN SUSTAIN THEMSELVES. EVEN
WITH THAT THOUGH...THINK COVERAGE WILL BE LIMITED AND MORE SO THAN
WHAT SEVERAL CONVECTIVE ALLOWING MODELS ARE SHOWING. CONVECTION
COULD CONCEIVABLY COME UP THE NEXT COUPLE HOURS AND THEN WANE AS
IT MOVES INTO THE FORECAST AREA.
POPS HAVE BEEN ADJUSTED AND LOWERED SOME TO ACCOUNT FOR LESS
COVERAGE WITH THE FRONT.
MTF
&&
.DISCUSSION...
316 PM CDT
THE MAIN FORECAST CONCERNS WILL FIRST FOCUS ON CONVECTIVE TRENDS
THIS EVENING AND OVERNIGHT...AND ALSO THE HEAT THROUGH THIS EVENING.
HOWEVER...OTHER CONCERNS IN THE FORECAST PERIOD WILL BE ADDITIONAL
THREATS OF CONVECTION/MCS`S LATER THIS WEEKEND INTO EARLY NEXT WEEK.
A COLD FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD ACROSS
SOUTHERN WISCONSIN. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY HAS
REMAINED FAIRLY WEAK AS A WELL MIXED WARM SECTOR HAS PRODUCED
SOUTHWESTERLY FLOW RELATIVELY PARALLEL WITH THE SURFACE FRONT. AS A
RESULT OF THIS...STORM DEVELOPMENT HAS REMAINED ISOLATED THUS FAR.
IN SPITE OF THIS ADDITIONAL STORMS ARE STILL EXPECTED TO DEVELOP
THROUGH THE AFTERNOON. FOR MORE INFO ON THESE STORMS REFERENCE THE
MESO DISCUSSION ABOVE.
THUNDERSTORMS WILL LIKELY BECOME HIGHER IN AERIAL COVERAGE EARLY
THIS EVENING AS LOWER LEVEL MOISTURE CONVERGENCE INCREASES AHEAD THIS
BOUNDARY. IT APPEARS THE FRONT WILL BE SLOW TO CLEAR NORTHERN
ILLINOIS...POSSIBLY NOT PASSING SOUTH OF CHICAGO UNTIL AFTER 03 UTC
THIS EVENING. THEREFORE...THUNDERSTORMS WILL BE POSSIBLY THROUGH AT
LEAST EARLY TO MID EVENING ACROSS MUCH OF ILLINOIS. THERE WILL STILL
BE A THREAT FOR STORMS TO PRODUCE MICROBURSTS WITH ISOLATED AREAS OF
STRONG DAMAGING WINDS INTO THIS EVENING AS DOWNDRAFT CAPE WILL
REMAIN IN EXCESS OF 1,000 J/KG. HOWEVER...THE OTHER THREAT WILL BE
TORRENTIAL DOWNPOURS WITH THESE THUNDERSTORMS. THE RICH THETA-E
AIR...WITH PWATS UP AROUND 2 INCHES WILL PROVIDE AMPLE CONDITIONS
FOR VERY HEAVY RAINFALL FROM THESE STORMS. MY CONCERN IS THAT AS THE
LOWER LEVEL CONVERGENCE INCREASES ALONG THE LOWER LEVEL FRONTAL
ZONE...THAT SOME OF THESE STORMS COULD TRAIN...WITH A NEARLY
EASTERLY CLOUD BEARING FLOW AROUND 25 KT EXPECTED...WHICH SHOULD BE
NEARLY PARALLEL TO THE BOUNDARY. IT APPEARS THE MAIN THREAT FOR THIS
WILL BE PRIMARILY SOUTH OF CHICAGO ACROSS MY EAST CENTRAL ILLINOIS
AND NORTHWESTERN ILLINOIS COUNTIES. I HAVE MAINTAINED THE HEAVY RAIN
WORDING IN THESE AREAS...ESPECIALLY THIS EVENING. THESE STORMS COULD
EASY DROP 1 TO 2 INCHES PER HOUR...AND IF THE STORMS TRAIN OVER THE
SAME AREAS THERE COULD BE SOME LOCALIZED AREAS OF HIGH RAINFALL
AMOUNTS. THIS WILL NEED TO BE WATCHED THIS EVENING. CONFIDENCE IN
WIDESPREAD HYDRO CONCERNS IN LOW...THEREFORE NO HEADLINES ARE
PLANNED.
THE THREAT FOR THUNDERSTORMS WITH HEAVY RAIN COULD CONTINUE
OVERNIGHT ACROSS MY FAR SOUTHERN COUNTIES AS IT APPEARS THE FRONTAL
BOUNDARY WILL BE SLOW TO MOVE ACROSS THESE AREAS. HOWEVER...IT
APPEARS THAT THE FRONT SHOULD CLEAR THE AREA BY EARLY SATURDAY
MORNING...ENDING THE THREAT FOR STORMS.
I WILL LEAVE THE HEAT HEADLINES AS IS...WITH AN ENDING TIME AT 00
UTC THIS EVENING. WITH THE DEW POINTS MIXING OUT INTO THE UPPER 60S
THE HEAT INDEX HAS NOT BEEN MUCH ABOVE 100. SO ALTHOUGH THE FRONT
WILL NOT MOVE THROUGH TILL TONIGHT...IT APPEARS THE BIG HEAT WILL BE
OVER BY 00 UTC...WITH COOLER AND LESS HUMID AIR TO MOVE IN LATER
TONIGHT.
SATURDAY AND SUNDAY WILL BE COOLER...WITH HIGHS MAINLY IN THE LOW TO
MID 80S...WITH AN ONSHORE FLOW. DRY CONDITIONS ARE EXPECTED FOR MUCH
OF THE WEEKEND. HOWEVER...THE CHANCE FOR MORE STORMS WILL INCREASE
LATE SUNDAY AND SUNDAY NIGHT AS ANOTHER DISTURBANCE APPROACHES THE
AREA. IT CURRENTLY APPEARS THE MAIN FOCUS MAY BE ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF MY AREA...BUT THE POTENTIAL FOR SOME
ADDITIONAL HEAVY RAIN AREA POSSIBLE INTO EARLY MONDAY.
SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE MAY LEAD TO LITTLE TO NO
CONVECTIVE ACTIVITY MONDAY AFTERNOON AND NIGHT. I HAVE THEREFORE
TRENDED POPS DOWN SIGNIFICANTLY FOR THIS TIMEFRAME. HOWEVER...A
FAIRLY DISTURBED WEST-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL
CONUS WILL LIKELY DRIVE ANOTHER DISTURBANCE OR TWO ACROSS THE AREA
ON TUESDAY. THIS WILL PRODUCE ANOTHER DECENT CHANCE OF THUNDERSTORMS
TUESDAY INTO TUESDAY EVENING.
ONCE THIS DISTURBANCE MOVES THROUGH...THE FLOW ALOFT LOOKS TO AMPLIFY
SOME...WITH BUILDING HEIGHTS ACROSS THE WESTERN CONUS. THIS SHOULD
ALLOW A COLD FRONT AND AREA OF SURFACE HIGH PRESSURE TO SHIFT
SOUTHWARD ACROSS THE GREAT LAKES REGION. THIS SHOULD RESULT IN THE
MAIN THREAT FOR CONVECTIVE ACTIVITY SHIFTING SOUTH OF THE REGION FOR
WEDNESDAY THROUGH THURSDAY...WITH A CONTINUATION OF COOL
TEMPERATURES INTO LATER NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* ISOLD-SCT SHRA/TSRA STILL POSSIBLE BUT HAVE SLOWED TIMING TO
01-04Z.
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* WIND DIR SHIFTING FROM WEST TO NORTH LATE THIS EVENING. THEN
WINDS STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT
THRU MIDDAY SAT WILL GENERALLY BE 7-10KT.
MDB
//DISCUSSION...UPDATED 22Z...
CONTINUING TO MONITOR TSRA POTENTIAL INTO THE EVENING. COLD
FRONTAL BOUNDARY FROM ROUGHLY GRB TO DLL TO PDC AT 22Z.
SATELLITE SHOWS SEVERAL NARROW BANDS OF FAIRLY WELL DEVELOPED CU
WITH THE CU RIGHT ALONG THE FRONT STARTING TO CATCH UP TO THE BAND
FURTHER AHEAD OF IT. DEVELOPMENT IS STARTING TO OCCUR AND COVERAGE
MAY INCREASE TO A DEGREE OVER THE NEXT HOUR AS THE TWO BANDS OF CU
MEET. ANY ACTIVITY THAT DOES DEVELOP WILL STILL BE SEVERAL HOURS
OUT FROM THE TERMINALS AND HAVE FURTHER SLOWED MENTION IN THE
TAFS...WITH ADDITIONAL SLOWING POSSIBLE. COVERAGE IS STILL IN
QUESTION...ESPECIALLY WITH EARLIEST ARRIVAL NEAR THE TERMINALS
COMING CLOSER TO SUNSET SO ACTIVITY COULD BE ON A DOWNWARD TREND.
MDB
FROM 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTABLE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH CONFIDENCE IN TIMING OF TSRA POTENTIAL...MEDIUM
CONFIDENCE IN OCCURRENCE.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
329 PM CDT
INITIAL CONCERN IN THE NEARSHORE WITH GUSTY WEST-SOUTHWEST WINDS
OCCASIONALLY TO 30 KT AHEAD OF A COLD FRONT. WITH SLOW PROGRESS OF
FRONT...IT IS POSSIBLE SMALL CRAFT ADVISORY MAY NEED TO BE EXTENDED
FOR A FEW HOURS INTO MID EVENING. ALSO A FEW GUSTY STORMS ARE
POSSIBLE THROUGH EARLY EVENING...WITH AN OUTSIDE CHANCE FOR GUSTS
OVER 50 KT. THIS INCLUDES THE OPEN WATERS.
BEHIND THE FRONT...A STRONG PUSH OF COOL AIR FOR THIS TIME OF YEAR
WILL MOVE DOWN THE LAKE RESULTING IN INCREASING NORTHERLY
WINDS...FIRST ON THE NORTH HALF SHIFTING TO THE SOUTH HALF DURING
THE DAY SATURDAY. THERE MAY BE OCCASIONAL GUSTS TO 30 KT OVER THE
OPEN WATERS. THEN HIGH PRESSURE WILL BUILD OVER THE LAKE BY SUNDAY
AND WINDS WILL DIMINISH. THOUGH LOW PRESSURE WILL MOVE OVER THE
REGION EARLY NEXT WEEK AND A COLD FRONT WILL PUSH ACROSS THE LAKE
BY TUESDAY...WINDS LOOK TO REMAIN FAIRLY LIGHT OUT OF THE SOUTH
UNTIL THE COLD FRONT PASSAGE. THEN AFTER THE FRONTAL PASSAGE LATE
TUESDAY...THERE COULD POTENTIALLY BE A PERIOD OF MODESTLY STRONGER
NORTHERLY WINDS FOLLOWED BY AN EXTENDED PERIOD OF LIGHT WINDS MID
TO LATE NEXT WEEK AS HIGH PRESSURE SPREADS ACROSS THE GREAT LAKES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 PM FRIDAY.
IN...HEAT ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM
FRIDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM FRIDAY.
&&
$$
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
510 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
MTF
&&
.DISCUSSION...
316 PM CDT
THE MAIN FORECAST CONCERNS WILL FIRST FOCUS ON CONVECTIVE TRENDS
THIS EVENING AND OVERNIGHT...AND ALSO THE HEAT THROUGH THIS EVENING.
HOWEVER...OTHER CONCERNS IN THE FORECAST PERIOD WILL BE ADDITIONAL
THREATS OF CONVECTION/MCS`S LATER THIS WEEKEND INTO EARLY NEXT WEEK.
A COLD FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD ACROSS
SOUTHERN WISCONSIN. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY HAS
REMAINED FAIRLY WEAK AS A WELL MIXED WARM SECTOR HAS PRODUCED
SOUTHWESTERLY FLOW RELATIVELY PARALLEL WITH THE SURFACE FRONT. AS A
RESULT OF THIS...STORM DEVELOPMENT HAS REMAINED ISOLATED THUS FAR.
IN SPITE OF THIS ADDITIONAL STORMS ARE STILL EXPECTED TO DEVELOP
THROUGH THE AFTERNOON. FOR MORE INFO ON THESE STORMS REFERENCE THE
MESO DISCUSSION ABOVE.
THUNDERSTORMS WILL LIKELY BECOME HIGHER IN AERIAL COVERAGE EARLY
THIS EVENING AS LOWER LEVEL MOISTURE CONVERGENCE INCREASES AHEAD THIS
BOUNDARY. IT APPEARS THE FRONT WILL BE SLOW TO CLEAR NORTHERN
ILLINOIS...POSSIBLY NOT PASSING SOUTH OF CHICAGO UNTIL AFTER 03 UTC
THIS EVENING. THEREFORE...THUNDERSTORMS WILL BE POSSIBLY THROUGH AT
LEAST EARLY TO MID EVENING ACROSS MUCH OF ILLINOIS. THERE WILL STILL
BE A THREAT FOR STORMS TO PRODUCE MICROBURSTS WITH ISOLATED AREAS OF
STRONG DAMAGING WINDS INTO THIS EVENING AS DOWNDRAFT CAPE WILL
REMAIN IN EXCESS OF 1,000 J/KG. HOWEVER...THE OTHER THREAT WILL BE
TORRENTIAL DOWNPOURS WITH THESE THUNDERSTORMS. THE RICH THETA-E
AIR...WITH PWATS UP AROUND 2 INCHES WILL PROVIDE AMPLE CONDITIONS
FOR VERY HEAVY RAINFALL FROM THESE STORMS. MY CONCERN IS THAT AS THE
LOWER LEVEL CONVERGENCE INCREASES ALONG THE LOWER LEVEL FRONTAL
ZONE...THAT SOME OF THESE STORMS COULD TRAIN...WITH A NEARLY
EASTERLY CLOUD BEARING FLOW AROUND 25 KT EXPECTED...WHICH SHOULD BE
NEARLY PARALLEL TO THE BOUNDARY. IT APPEARS THE MAIN THREAT FOR THIS
WILL BE PRIMARILY SOUTH OF CHICAGO ACROSS MY EAST CENTRAL ILLINOIS
AND NORTHWESTERN ILLINOIS COUNTIES. I HAVE MAINTAINED THE HEAVY RAIN
WORDING IN THESE AREAS...ESPECIALLY THIS EVENING. THESE STORMS COULD
EASY DROP 1 TO 2 INCHES PER HOUR...AND IF THE STORMS TRAIN OVER THE
SAME AREAS THERE COULD BE SOME LOCALIZED AREAS OF HIGH RAINFALL
AMOUNTS. THIS WILL NEED TO BE WATCHED THIS EVENING. CONFIDENCE IN
WIDESPREAD HYDRO CONCERNS IN LOW...THEREFORE NO HEADLINES ARE
PLANNED.
THE THREAT FOR THUNDERSTORMS WITH HEAVY RAIN COULD CONTINUE
OVERNIGHT ACROSS MY FAR SOUTHERN COUNTIES AS IT APPEARS THE FRONTAL
BOUNDARY WILL BE SLOW TO MOVE ACROSS THESE AREAS. HOWEVER...IT
APPEARS THAT THE FRONT SHOULD CLEAR THE AREA BY EARLY SATURDAY
MORNING...ENDING THE THREAT FOR STORMS.
I WILL LEAVE THE HEAT HEADLINES AS IS...WITH AN ENDING TIME AT 00
UTC THIS EVENING. WITH THE DEW POINTS MIXING OUT INTO THE UPPER 60S
THE HEAT INDEX HAS NOT BEEN MUCH ABOVE 100. SO ALTHOUGH THE FRONT
WILL NOT MOVE THROUGH TILL TONIGHT...IT APPEARS THE BIG HEAT WILL BE
OVER BY 00 UTC...WITH COOLER AND LESS HUMID AIR TO MOVE IN LATER
TONIGHT.
SATURDAY AND SUNDAY WILL BE COOLER...WITH HIGHS MAINLY IN THE LOW TO
MID 80S...WITH AN ONSHORE FLOW. DRY CONDITIONS ARE EXPECTED FOR MUCH
OF THE WEEKEND. HOWEVER...THE CHANCE FOR MORE STORMS WILL INCREASE
LATE SUNDAY AND SUNDAY NIGHT AS ANOTHER DISTURBANCE APPROACHES THE
AREA. IT CURRENTLY APPEARS THE MAIN FOCUS MAY BE ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF MY AREA...BUT THE POTENTIAL FOR SOME
ADDITIONAL HEAVY RAIN AREA POSSIBLE INTO EARLY MONDAY.
SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE MAY LEAD TO LITTLE TO NO
CONVECTIVE ACTIVITY MONDAY AFTERNOON AND NIGHT. I HAVE THEREFORE
TRENDED POPS DOWN SIGNIFICANTLY FOR THIS TIMEFRAME. HOWEVER...A
FAIRLY DISTURBED WEST-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL
CONUS WILL LIKELY DRIVE ANOTHER DISTURBANCE OR TWO ACROSS THE AREA
ON TUESDAY. THIS WILL PRODUCE ANOTHER DECENT CHANCE OF THUNDERSTORMS
TUESDAY INTO TUESDAY EVENING.
ONCE THIS DISTURBANCE MOVES THROUGH...THE FLOW ALOFT LOOKS TO AMPLIFY
SOME...WITH BUILDING HEIGHTS ACROSS THE WESTERN CONUS. THIS SHOULD
ALLOW A COLD FRONT AND AREA OF SURFACE HIGH PRESSURE TO SHIFT
SOUTHWARD ACROSS THE GREAT LAKES REGION. THIS SHOULD RESULT IN THE
MAIN THREAT FOR CONVECTIVE ACTIVITY SHIFTING SOUTH OF THE REGION FOR
WEDNESDAY THROUGH THURSDAY...WITH A CONTINUATION OF COOL
TEMPERATURES INTO LATER NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* ISOLD-SCT SHRA/TSRA STILL POSSIBLE BUT HAVE SLOWED TIMING TO
01-04Z.
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* WIND DIR SHIFTING FROM WEST TO NORTH LATE THIS EVENING. THEN
WINDS STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT
THRU MIDDAY SAT WILL GENERALLY BE 7-10KT.
MDB
//DISCUSSION...UPDATED 22Z...
CONTINUING TO MONITOR TSRA POTENTIAL INTO THE EVENING. COLD
FRONTAL BOUNDARY FROM ROUGHLY GRB TO DLL TO PDC AT 22Z.
SATELLITE SHOWS SEVERAL NARROW BANDS OF FAIRLY WELL DEVELOPED CU
WITH THE CU RIGHT ALONG THE FRONT STARTING TO CATCH UP TO THE BAND
FURTHER AHEAD OF IT. DEVELOPMENT IS STARTING TO OCCUR AND COVERAGE
MAY INCREASE TO A DEGREE OVER THE NEXT HOUR AS THE TWO BANDS OF CU
MEET. ANY ACTIVITY THAT DOES DEVELOP WILL STILL BE SEVERAL HOURS
OUT FROM THE TERMINALS AND HAVE FURTHER SLOWED MENTION IN THE
TAFS...WITH ADDITIONAL SLOWING POSSIBLE. COVERAGE IS STILL IN
QUESTION...ESPECIALLY WITH EARLIEST ARRIVAL NEAR THE TERMINALS
COMING CLOSER TO SUNSET SO ACTIVITY COULD BE ON A DOWNWARD TREND.
MDB
FROM 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTABLE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH CONFIDENCE IN TIMING OF TSRA POTENTIAL...MEDIUM
CONFIDENCE IN OCCURRENCE.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
329 PM CDT
INITIAL CONCERN IN THE NEARSHORE WITH GUSTY WEST-SOUTHWEST WINDS
OCCASIONALLY TO 30 KT AHEAD OF A COLD FRONT. WITH SLOW PROGRESS OF
FRONT...IT IS POSSIBLE SMALL CRAFT ADVISORY MAY NEED TO BE EXTENDED
FOR A FEW HOURS INTO MID EVENING. ALSO A FEW GUSTY STORMS ARE
POSSIBLE THROUGH EARLY EVENING...WITH AN OUTSIDE CHANCE FOR GUSTS
OVER 50 KT. THIS INCLUDES THE OPEN WATERS.
BEHIND THE FRONT...A STRONG PUSH OF COOL AIR FOR THIS TIME OF YEAR
WILL MOVE DOWN THE LAKE RESULTING IN INCREASING NORTHERLY
WINDS...FIRST ON THE NORTH HALF SHIFTING TO THE SOUTH HALF DURING
THE DAY SATURDAY. THERE MAY BE OCCASIONAL GUSTS TO 30 KT OVER THE
OPEN WATERS. THEN HIGH PRESSURE WILL BUILD OVER THE LAKE BY SUNDAY
AND WINDS WILL DIMINISH. THOUGH LOW PRESSURE WILL MOVE OVER THE
REGION EARLY NEXT WEEK AND A COLD FRONT WILL PUSH ACROSS THE LAKE
BY TUESDAY...WINDS LOOK TO REMAIN FAIRLY LIGHT OUT OF THE SOUTH
UNTIL THE COLD FRONT PASSAGE. THEN AFTER THE FRONTAL PASSAGE LATE
TUESDAY...THERE COULD POTENTIALLY BE A PERIOD OF MODESTLY STRONGER
NORTHERLY WINDS FOLLOWED BY AN EXTENDED PERIOD OF LIGHT WINDS MID
TO LATE NEXT WEEK AS HIGH PRESSURE SPREADS ACROSS THE GREAT LAKES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 PM FRIDAY.
IN...HEAT ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM
FRIDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM FRIDAY.
&&
$$
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
329 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...239 PM CDT
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
MTF
&&
.DISCUSSION...
316 PM CDT
THE MAIN FORECAST CONCERNS WILL FIRST FOCUS ON CONVECTIVE TRENDS
THIS EVENING AND OVERNIGHT...AND ALSO THE HEAT THROUGH THIS EVENING.
HOWEVER...OTHER CONCERNS IN THE FORECAST PERIOD WILL BE ADDITIONAL
THREATS OF CONVECTION/MCS`S LATER THIS WEEKEND INTO EARLY NEXT WEEK.
A COLD FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD ACROSS
SOUTHERN WISCONSIN. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY HAS
REMAINED FAIRLY WEAK AS A WELL MIXED WARM SECTOR HAS PRODUCED
SOUTHWESTERLY FLOW RELATIVELY PARALLEL WITH THE SURFACE FRONT. AS A
RESULT OF THIS...STORM DEVELOPMENT HAS REMAINED ISOLATED THUS FAR.
IN SPITE OF THIS ADDITIONAL STORMS ARE STILL EXPECTED TO DEVELOP
THROUGH THE AFTERNOON. FOR MORE INFO ON THESE STORMS REFERENCE THE
MESO DISCUSSION ABOVE.
THUNDERSTORMS WILL LIKELY BECOME HIGHER IN AERIAL COVERAGE EARLY
THIS EVENING AS LOWER LEVEL MOISTURE CONVERGENCE INCREASES AHEAD THIS
BOUNDARY. IT APPEARS THE FRONT WILL BE SLOW TO CLEAR NORTHERN
ILLINOIS...POSSIBLY NOT PASSING SOUTH OF CHICAGO UNTIL AFTER 03 UTC
THIS EVENING. THEREFORE...THUNDERSTORMS WILL BE POSSIBLY THROUGH AT
LEAST EARLY TO MID EVENING ACROSS MUCH OF ILLINOIS. THERE WILL STILL
BE A THREAT FOR STORMS TO PRODUCE MICROBURSTS WITH ISOLATED AREAS OF
STRONG DAMAGING WINDS INTO THIS EVENING AS DOWNDRAFT CAPE WILL
REMAIN IN EXCESS OF 1,000 J/KG. HOWEVER...THE OTHER THREAT WILL BE
TORRENTIAL DOWNPOURS WITH THESE THUNDERSTORMS. THE RICH THETA-E
AIR...WITH PWATS UP AROUND 2 INCHES WILL PROVIDE AMPLE CONDITIONS
FOR VERY HEAVY RAINFALL FROM THESE STORMS. MY CONCERN IS THAT AS THE
LOWER LEVEL CONVERGENCE INCREASES ALONG THE LOWER LEVEL FRONTAL
ZONE...THAT SOME OF THESE STORMS COULD TRAIN...WITH A NEARLY
EASTERLY CLOUD BEARING FLOW AROUND 25 KT EXPECTED...WHICH SHOULD BE
NEARLY PARALLEL TO THE BOUNDARY. IT APPEARS THE MAIN THREAT FOR THIS
WILL BE PRIMARILY SOUTH OF CHICAGO ACROSS MY EAST CENTRAL ILLINOIS
AND NORTHWESTERN ILLINOIS COUNTIES. I HAVE MAINTAINED THE HEAVY RAIN
WORDING IN THESE AREAS...ESPECIALLY THIS EVENING. THESE STORMS COULD
EASY DROP 1 TO 2 INCHES PER HOUR...AND IF THE STORMS TRAIN OVER THE
SAME AREAS THERE COULD BE SOME LOCALIZED AREAS OF HIGH RAINFALL
AMOUNTS. THIS WILL NEED TO BE WATCHED THIS EVENING. CONFIDENCE IN
WIDESPREAD HYDRO CONCERNS IN LOW...THEREFORE NO HEADLINES ARE
PLANNED.
THE THREAT FOR THUNDERSTORMS WITH HEAVY RAIN COULD CONTINUE
OVERNIGHT ACROSS MY FAR SOUTHERN COUNTIES AS IT APPEARS THE FRONTAL
BOUNDARY WILL BE SLOW TO MOVE ACROSS THESE AREAS. HOWEVER...IT
APPEARS THAT THE FRONT SHOULD CLEAR THE AREA BY EARLY SATURDAY
MORNING...ENDING THE THREAT FOR STORMS.
I WILL LEAVE THE HEAT HEADLINES AS IS...WITH AN ENDING TIME AT 00
UTC THIS EVENING. WITH THE DEW POINTS MIXING OUT INTO THE UPPER 60S
THE HEAT INDEX HAS NOT BEEN MUCH ABOVE 100. SO ALTHOUGH THE FRONT
WILL NOT MOVE THROUGH TILL TONIGHT...IT APPEARS THE BIG HEAT WILL BE
OVER BY 00 UTC...WITH COOLER AND LESS HUMID AIR TO MOVE IN LATER
TONIGHT.
SATURDAY AND SUNDAY WILL BE COOLER...WITH HIGHS MAINLY IN THE LOW TO
MID 80S...WITH AN ONSHORE FLOW. DRY CONDITIONS ARE EXPECTED FOR MUCH
OF THE WEEKEND. HOWEVER...THE CHANCE FOR MORE STORMS WILL INCREASE
LATE SUNDAY AND SUNDAY NIGHT AS ANOTHER DISTURBANCE APPROACHES THE
AREA. IT CURRENTLY APPEARS THE MAIN FOCUS MAY BE ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF MY AREA...BUT THE POTENTIAL FOR SOME
ADDITIONAL HEAVY RAIN AREA POSSIBLE INTO EARLY MONDAY.
SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE MAY LEAD TO LITTLE TO NO
CONVECTIVE ACTIVITY MONDAY AFTERNOON AND NIGHT. I HAVE THEREFORE
TRENDED POPS DOWN SIGNIFICANTLY FOR THIS TIMEFRAME. HOWEVER...A
FAIRLY DISTURBED WEST-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL
CONUS WILL LIKELY DRIVE ANOTHER DISTURBANCE OR TWO ACROSS THE AREA
ON TUESDAY. THIS WILL PRODUCE ANOTHER DECENT CHANCE OF THUNDERSTORMS
TUESDAY INTO TUESDAY EVENING.
ONCE THIS DISTURBANCE MOVES THROUGH...THE FLOW ALOFT LOOKS TO AMPLIFY
SOME...WITH BUILDING HEIGHTS ACROSS THE WESTERN CONUS. THIS SHOULD
ALLOW A COLD FRONT AND AREA OF SURFACE HIGH PRESSURE TO SHIFT
SOUTHWARD ACROSS THE GREAT LAKES REGION. THIS SHOULD RESULT IN THE
MAIN THREAT FOR CONVECTIVE ACTIVITY SHIFTING SOUTH OF THE REGION FOR
WEDNESDAY THROUGH THURSDAY...WITH A CONTINUATION OF COOL
TEMPERATURES INTO LATER NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* ISO SHRA/TSRA DEVELOPING...BEST TIMING FOR STRONGER TSRA WOULD
BE AFT 21Z THRU 01Z.
* WIND DIR SHIFTING FROM WEST TO NORTH THIS EVENING. THEN WINDS
STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT THRU
MIDDAY SAT WILL GENERALLY BE 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTBALE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN SCT TSRA THIS AFTERNOON THRU EARLY EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL/ENDING AT ORD/MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
329 PM CDT
INITIAL CONCERN IN THE NEARSHORE WITH GUSTY WEST-SOUTHWEST WINDS
OCCASIONALLY TO 30 KT AHEAD OF A COLD FRONT. WITH SLOW PROGRESS OF
FRONT...IT IS POSSIBLE SMALL CRAFT ADVISORY MAY NEED TO BE EXTENDED
FOR A FEW HOURS INTO MID EVENING. ALSO A FEW GUSTY STORMS ARE
POSSIBLE THROUGH EARLY EVENING...WITH AN OUTSIDE CHANCE FOR GUSTS
OVER 50 KT. THIS INCLUDES THE OPEN WATERS.
BEHIND THE FRONT...A STRONG PUSH OF COOL AIR FOR THIS TIME OF YEAR
WILL MOVE DOWN THE LAKE RESULTING IN INCREASING NORTHERLY
WINDS...FIRST ON THE NORTH HALF SHIFTING TO THE SOUTH HALF DURING
THE DAY SATURDAY. THERE MAY BE OCCASIONAL GUSTS TO 30 KT OVER THE
OPEN WATERS. THEN HIGH PRESSURE WILL BUILD OVER THE LAKE BY SUNDAY
AND WINDS WILL DIMINISH. THOUGH LOW PRESSURE WILL MOVE OVER THE
REGION EARLY NEXT WEEK AND A COLD FRONT WILL PUSH ACROSS THE LAKE
BY TUESDAY...WINDS LOOK TO REMAIN FAIRLY LIGHT OUT OF THE SOUTH
UNTIL THE COLD FRONT PASSAGE. THEN AFTER THE FRONTAL PASSAGE LATE
TUESDAY...THERE COULD POTENTIALLY BE A PERIOD OF MODESTLY STRONGER
NORTHERLY WINDS FOLLOWED BY AN EXTENDED PERIOD OF LIGHT WINDS MID
TO LATE NEXT WEEK AS HIGH PRESSURE SPREADS ACROSS THE GREAT LAKES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 PM FRIDAY.
IN...HEAT ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM
FRIDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM FRIDAY.
&&
$$
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
317 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
239 PM CDT
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
MTF
&&
.DISCUSSION...
316 PM CDT
THE MAIN FORECAST CONCERNS WILL FIRST FOCUS ON CONVECTIVE TRENDS
THIS EVENING AND OVERNIGHT...AND ALSO THE HEAT THROUGH THIS EVENING.
HOWEVER...OTHER CONCERNS IN THE FORECAST PERIOD WILL BE ADDITIONAL
THREATS OF CONVECTION/MCS`S LATER THIS WEEKEND INTO EARLY NEXT WEEK.
A COLD FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD ACROSS
SOUTHERN WISCONSIN. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY HAS
REMAINED FAIRLY WEAK AS A WELL MIXED WARM SECTOR HAS PRODUCED
SOUTHWESTERLY FLOW RELATIVELY PARALLEL WITH THE SURFACE FRONT. AS A
RESULT OF THIS...STORM DEVELOPMENT HAS REMAINED ISOLATED THUS FAR.
IN SPITE OF THIS ADDITIONAL STORMS ARE STILL EXPECTED TO DEVELOP
THROUGH THE AFTERNOON. FOR MORE INFO ON THESE STORMS REFERENCE THE
MESO DISCUSSION ABOVE.
THUNDERSTORMS WILL LIKELY BECOME HIGHER IN AERIAL COVERAGE EARLY
THIS EVENING AS LOWER LEVEL MOISTURE CONVERGENCE INCREASES AHEAD THIS
BOUNDARY. IT APPEARS THE FRONT WILL BE SLOW TO CLEAR NORTHERN
ILLINOIS...POSSIBLY NOT PASSING SOUTH OF CHICAGO UNTIL AFTER 03 UTC
THIS EVENING. THEREFORE...THUNDERSTORMS WILL BE POSSIBLY THROUGH AT
LEAST EARLY TO MID EVENING ACROSS MUCH OF ILLINOIS. THERE WILL STILL
BE A THREAT FOR STORMS TO PRODUCE MICROBURSTS WITH ISOLATED AREAS OF
STRONG DAMAGING WINDS INTO THIS EVENING AS DOWNDRAFT CAPE WILL
REMAIN IN EXCESS OF 1,000 J/KG. HOWEVER...THE OTHER THREAT WILL BE
TORRENTIAL DOWNPOURS WITH THESE THUNDERSTORMS. THE RICH THETA-E
AIR...WITH PWATS UP AROUND 2 INCHES WILL PROVIDE AMPLE CONDITIONS
FOR VERY HEAVY RAINFALL FROM THESE STORMS. MY CONCERN IS THAT AS THE
LOWER LEVEL CONVERGENCE INCREASES ALONG THE LOWER LEVEL FRONTAL
ZONE...THAT SOME OF THESE STORMS COULD TRAIN...WITH A NEARLY
EASTERLY CLOUD BEARING FLOW AROUND 25 KT EXPECTED...WHICH SHOULD BE
NEARLY PARALLEL TO THE BOUNDARY. IT APPEARS THE MAIN THREAT FOR THIS
WILL BE PRIMARILY SOUTH OF CHICAGO ACROSS MY EAST CENTRAL ILLINOIS
AND NORTHWESTERN ILLINOIS COUNTIES. I HAVE MAINTAINED THE HEAVY RAIN
WORDING IN THESE AREAS...ESPECIALLY THIS EVENING. THESE STORMS COULD
EASY DROP 1 TO 2 INCHES PER HOUR...AND IF THE STORMS TRAIN OVER THE
SAME AREAS THERE COULD BE SOME LOCALIZED AREAS OF HIGH RAINFALL
AMOUNTS. THIS WILL NEED TO BE WATCHED THIS EVENING. CONFIDENCE IN
WIDESPREAD HYDRO CONCERNS IN LOW...THEREFORE NO HEADLINES ARE
PLANNED.
THE THREAT FOR THUNDERSTORMS WITH HEAVY RAIN COULD CONTINUE
OVERNIGHT ACROSS MY FAR SOUTHERN COUNTIES AS IT APPEARS THE FRONTAL
BOUNDARY WILL BE SLOW TO MOVE ACROSS THESE AREAS. HOWEVER...IT
APPEARS THAT THE FRONT SHOULD CLEAR THE AREA BY EARLY SATURDAY
MORNING...ENDING THE THREAT FOR STORMS.
I WILL LEAVE THE HEAT HEADLINES AS IS...WITH AN ENDING TIME AT 00
UTC THIS EVENING. WITH THE DEW POINTS MIXING OUT INTO THE UPPER 60S
THE HEAT INDEX HAS NOT BEEN MUCH ABOVE 100. SO ALTHOUGH THE FRONT
WILL NOT MOVE THROUGH TILL TONIGHT...IT APPEARS THE BIG HEAT WILL BE
OVER BY 00 UTC...WITH COOLER AND LESS HUMID AIR TO MOVE IN LATER
TONIGHT.
SATURDAY AND SUNDAY WILL BE COOLER...WITH HIGHS MAINLY IN THE LOW TO
MID 80S...WITH AN ONSHORE FLOW. DRY CONDITIONS ARE EXPECTED FOR MUCH
OF THE WEEKEND. HOWEVER...THE CHANCE FOR MORE STORMS WILL INCREASE
LATE SUNDAY AND SUNDAY NIGHT AS ANOTHER DISTURBANCE APPROACHES THE
AREA. IT CURRENTLY APPEARS THE MAIN FOCUS MAY BE ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF MY AREA...BUT THE POTENTIAL FOR SOME
ADDITIONAL HEAVY RAIN AREA POSSIBLE INTO EARLY MONDAY.
SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE MAY LEAD TO LITTLE TO NO
CONVECTIVE ACTIVITY MONDAY AFTERNOON AND NIGHT. I HAVE THEREFORE
TRENDED POPS DOWN SIGNIFICANTLY FOR THIS TIMEFRAME. HOWEVER...A
FAIRLY DISTURBED WEST-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL
CONUS WILL LIKELY DRIVE ANOTHER DISTURBANCE OR TWO ACROSS THE AREA
ON TUESDAY. THIS WILL PRODUCE ANOTHER DECENT CHANCE OF THUNDERSTORMS
TUESDAY INTO TUESDAY EVENING.
ONCE THIS DISTURBANCE MOVES THROUGH...THE FLOW ALOFT LOOKS TO AMPLIFY
SOME...WITH BUILDING HEIGHTS ACROSS THE WESTERN CONUS. THIS SHOULD
ALLOW A COLD FRONT AND AREA OF SURFACE HIGH PRESSURE TO SHIFT
SOUTHWARD ACROSS THE GREAT LAKES REGION. THIS SHOULD RESULT IN THE
MAIN THREAT FOR CONVECTIVE ACTIVITY SHIFTING SOUTH OF THE REGION FOR
WEDNESDAY THROUGH THURSDAY...WITH A CONTINUATION OF COOL
TEMPERATURES INTO LATER NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* ISO SHRA/TSRA DEVELOPING...BEST TIMING FOR STRONGER TSRA WOULD
BE AFT 21Z THRU 01Z.
* WIND DIR SHIFTING FROM WEST TO NORTH THIS EVENING. THEN WINDS
STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT THRU
MIDDAY SAT WILL GENERALLY BE 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTBALE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN SCT TSRA THIS AFTERNOON THRU EARLY EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL/ENDING AT ORD/MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
A BROAD RIDGE OF HIGH PRESSURE EXTENDS FROM THE SOUTH HIGH PLAINS
THROUGH THE OHIO VALLEY. THIS RIDGE WILL SAG SOUTHEAST AND STALL
OUT OVER THE GULF COAST REGION LATE FRIDAY. MEANWHILE...LOW
PRESSURE OVER JAMES BAY WILL DEEPEN SLIGHTLY AS IT TRACKS EAST TO
NORTHERN QUEBEC...WHILE DRAGGING A COLD FRONT SOUTH ACROSS THE LAKE
FRIDAY. SOUTHWEST WINDS WILL INCREASE TO AROUND 30KT OVER MUCH OF
THE LAKE TODAY AS THE GRADIENT STRENGTHENS IN ADVACE OF THE COLD
FRONT. WINDS WILL THEN SHIFT TO MORE NORTHERLY BEHIND THE
FRONT...TEMPORARILY WEAKENING FOR A BRIEF PERIOD FRIDAY NIGHT. A
SECONDARY SURGE OF COOLER AIR WILL PUSH DOWN THE LAKE LATE FRIDAY
NIGHT AND SATURDAY STRENGTHENING THE WINDS TO AROUND 25KT WHILE
VEERING THROUGH NORTHERLY TO NORTHEASTERLY. AS HIGH PRESSURE
BUILDS FROM CENTRAL CANADA INTO THE UPPER MISSISSIPPI VALLEY AND
WESTERN GREAT LAKES...WINDS WILL THEN VEER EASTERLY OVER THE
LAKE...WHILE REMAINING RATHER BRISK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 PM FRIDAY.
IN...HEAT ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM
FRIDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM FRIDAY.
&&
$$
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...UPDATED
NWS CHICAGO/ROMEOVILLE IL
240 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
239 PM CDT
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
MTF
&&
.DISCUSSION...
1138 AM CDT
THE MORNING CONVECTION AND THE ASSOCIATED CLOUD COVER HAVE
DISSIPATED OVER THE PAST COUPLE HOURS ACROSS SOUTHERN WISCONSIN. IT
APPEARS AN OUTFLOW BOUNDARY...LIKELY ELEVATED IS PUSHING ACROSS
NORTHERN ILLINOIS AT THIS TIME. WITH SKIES REMAINING CLEAR ACROSS THE
REGION...TEMPERATURES ARE QUICKLY WARMING INTO THE LOW 90S EARLY
THIS MORNING. WITH EVEN WARM 925 MB TEMPERATURES TODAY NEAR 27
DEGREES C...PER 12 UTC DVN RAOB...I SEE NO REASON WHY TEMPERATURES
WILL NOT WARM INTO THE MIDDLE 90S BY EARLY AFTERNOON. THEREFORE...I
WARMED TEMPERATURES A FEW DEGREES. THE INCREASING SOUTHWESTERLY
WINDS SHOULD HELP MIX OUT DEW POINTS SOME...RESULTING IN SOME
SLIGHTLY LOWER DEW POINTS IN THE UPPER 60S TO THE LOW 70S.
THEREFORE...HEAT INDEX VALUES STILL APPEAR TO PEAK NEAR 105 THIS
AFTERNOON.
IT APPEARS CONVECTION WILL FIRE UP ACROSS NORTHERN ILLINOIS AFTER 19
UTC. MODIFYING DVN 12 UTC RAOB FOR CURRENT CONDITIONS INDICATE VERY
LITTLE CAP REMAINING ACROSS THE AREA WITH SB CAPE AROUND 2800 J/KG.
THEREFORE...IT IS NOT SURPRISING THAT THE REGIONAL SATELLITE IMAGERY
SHOWS AN AREA OF CLOUD COVER WITH INCREASING AGITATION ACROSS
PORTIONS OF IOWA. THIS AREA ALSO COINCIDES WITH SOME ENHANCED
BOUNDARY LAYER CONVERGENCE JUST AHEAD OF THE SURFACE COLD FRONT.
THIS ACTIVITY SHOULD CONTINUE TO DEVELOP AND MOVE TOWARDS MY
NORTHERN COUNTIES AFTER 19 OR 20 UTC AS THE SURFACE FRONT CONTINUES
TO DROP SOUTHWARD. ADDITIONAL ISOLATED TO SCATTERED CONVECTION COULD
ALSO DEVELOP FARTHER SOUTH AND EAST ACROSS THE SOUTHERN SUBURBS OF
CHICAGO AND INTO NORTHWESTERN INDIANA THIS AFTERNOON...IN
ASSOCIATION WITH INCREASING BOUNDARY LAYER CONVERGENCE ALONG A
PREFRONTAL TROUGH.
IT APPEARS THE MAIN SEVERE THREAT FROM THIS ACTIVITY WILL BE
DAMAGING WIND GUSTS. DEEP LAYER SHEAR REMAINS RELATIVELY WEAK...20
TO 25 KT...MAINLY DUE TO THE STRONGER MID LEVEL FLOW REMAINING TO
THE NORTH BEHIND THE FRONT. HOWEVER...WET OR EVEN HYBRID
MICROBURSTS ARE LIKELY WITH THIS ACTIVITY WITH LAYER THETA-E
DIFFERENCES IN EXCESS OF 20 DEGREES C.
THE OTHER THREAT WILL BE THAT OF TORRENTIAL DOWNPOURS WITH THIS
ACTIVITY. PWATS ARE PROGGED TO BY AROUND 2 INCHES...THEREFORE THESE
STORMS WILL HAVE PLENTY OF HIGH THETA-E AIR TO WORK WITH. RAINFALL
RATES IN SOME OF THESE STORMS COULD EASILY EXCEED AN INCH OR TWO AN
HOUR...WHICH COULD RESULT IN SOME LOCALIZED HYDRO
ISSUES...ESPECIALLY IF THIS OCCURS OVER THE URBAN AREAS. I DECIDED
TO ADD HEAVY RAINFALL TO THE GRIDS EARLY THIS EVENING...BUT I KEPT
IT SOUTH OF CHICAGO...MAINLY ACROSS EAST CENTRAL ILLINOIS AND
NORTHWESTERN INDIANA WHERE THE CONVECTIVE ACTIVITY COULD LINGER
THIS EVENING. STORM MOTIONS SHOULD BE TO THE EAST AROUND 25
KT...SO THE POTENTIAL FOR SOME TRAINING CELLS COULD RESULT IN
LOCAL HEAVY RAINFALL AMOUNTS.
KJB
//PREV DISCUSSION...
337 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE HEAT AND THUNDERSTORMS
CHANCES TODAY...FOLLOWED BY POPS/TSTORM CHANCES NEXT WEEK AS WE GET
INTO A POTENTIALLY MORE UNSETTLED PATTERN AFTER A RETURN TO MORE
SEASONABLE TEMPS THIS WEEKEND.
TRICKY FORECAST FOR HEAT TODAY AS NORTHERN AND NORTHWESTERN PORTIONS
OF THE CWA WILL SEE CONVECTIVE POTENTIAL RAMPING UP BY LATE MORNING
WITH CLOUDINESS INCREASING. IN ADDITION...GOES SOUNDER PWAT IMAGERY
SHOWS A SWATH OF LOWER PWAT AIR UPSTREAM AHEAD OF THE FRONT AND THIS
WAS CONFIRMED IN 00Z SOUNDINGS WITH 925MB DEWPOINTS 5C+ LOWER THAN
ILX/DVN. IN THIS REGION...STRONGER SOUTHWEST WINDS ALLOWED DEWPOINTS
TO MIX OUT IN THE 60S THURS AFTERNOON AND AM CONCERNED WE COULD SEE
SOMETHING SIMILAR HAPPEN HERE TODAY MAKING IT HARD FOR HEAT INDICES
TO REACH 100F. RUC...WHICH DID SEEM TO INITIALIZE THIS DRIER AIR OK
SHOWS IT GETTING PINCHED OFF THIS MORNING WITH NO APPRECIABLE DROP
IN DEWPOINTS TODAY. IN REALITY...WE`RE PROBABLY TALKING ABOUT THE
DIFFERENCE BETWEEN HEAT INDICES IN THE MID-UPPER 90S VS UP TO
100-105 WHICH IS PRETTY TRIVIAL DETAIL AT THIS POINT. NO SIGNIFICANT
CHANGES WERE MADE TO FORECAST TEMPS OR HEAT INDICES...SO NO PLANS TO
ALTER HEADLINES AT THIS TIME.
CONVECTION HAS FINALLY BEGUN TO LIGHT UP DOWN THE FRONT OVER
SOUTHERN MN WHICH GUIDANCE HAS BEEN SUGGESTING WOULD HAVE HAPPENED
HOURS AGO. MANY OF THE CONVECTIVE ALLOWING MODELS (CAMS) HOLD ONTO
THIS CONVECTION OR ITS OUTFLOW THROUGH THE MORNING WITH
RE-INTENSIFICATION TAKING PLACE LATER THIS MORNING OVER SOUTHERN WI
INTO N IL AS THE BOUNDARY LAYER RAPIDLY DESTABILIZES. GLANCING BLOW
OF MID LEVEL HEIGHT FALLS ALONG WITH APPROACHING COLD FRONT AND
STRONG INSTABILITY FAVOR SCATTERED TO POTENTIALLY NUMEROUS
THUNDERSTORMS MOVING ACROSS THE AREA THIS AFTERNOON AND LINGERING
INTO THIS EVENING SOUTH. CERTAINLY INSTABILITY WILL NOT BE
LACKING...BUT GUIDANCE STRONGLY SUGGESTS THAT THE STRONGER FLOW
ALOFT WILL LAG BEHIND THE FRONT AND CONVECTION TODAY WITH 0-6KM
SHEAR MAGNITUDE OF GENERALLY LESS THAN 20KT. GIVEN THE WEAK
SHEAR...VERY WARM TEMPS ALOFT (WET BULB ZERO RISING TO OVER 14KFT)
AND WEAK MID LEVEL LAPSE RATES THE THREAT OF HAIL LOOKS MINIMAL. THE
WEAK SHEAR ALSO SUGGESTS MINIMAL STORM SCALE ORGANIZATION OR
LONGEVITY WITH ANY SEVERE THREAT LIKELY LIMITED TO SPOTTY PULSE TYPE
MICROBURSTS WITH WHAT LIMITED SEVERE THREAT THERE IS LIKELY
DIMINISHING FURTHER WITH SUNSET.
NORTHERLY WINDS BEHIND THE FRONT LATER TONIGHT AND SATURDAY WILL
GRADUALLY ADVECT IN LOWER DEWPOINTS AND COOLER TEMPERATURES...BUT AS
IS TYPICAL WITH SUMMERTIME FRONT THE ARRIVAL OF THE COOLER/DRIER AIR
WILL BE A GRADUAL PROCESS BEHIND THE FRONT. BY SUNDAY AND INTO THE
FIRST HALF OF NEXT WEEK WITH A LOW AMPLITUDE WEST-NORTHWEST FLOW
OVER THE REGION WITH MULTIPLE WEAK SHORTWAVES RIDING THIS FLOW INTO
THE AREA BRINGING AT LEAST PERIODIC CHANCES OF SHOWERS AND
THUNDERSTORMS. UNFORTUNATELY MODELS ARE ALL OVER THE PLACE IN TIMING
AND INTENSITY OF THESE LOW AMPLITUDE FEATURES AND RESULTANT MCS
ACTIVITY LENDING TO A LOW CONFIDENCE FORECAST. GIVEN THE LOW
PREDICTABILITY OF THESE FEATURES WAS LEFT WITH LITTLE CHOICE THAN TO
PAINT PERIOD AFTER PERIOD IN THE FORECAST WITH CHANCES POPS...WHEN
IN REALITY MUCH OF THE PERIOD WILL BE DRY. TEMPERATURES GENERALLY
LOOK TO BE FAIRLY SEASONABLE THROUGH THIS PERIOD...WITH DAYTIME
TEMPS LIKELY AFFECTED TO A LARGE EXTENT BY COVERAGE OF PRECIP AND
CLOUDINESS.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* ISO SHRA/TSRA DEVELOPING...BEST TIMING FOR STRONGER TSRA WOULD
BE AFT 21Z THRU 01Z.
* WIND DIR SHIFTING FROM WEST TO NORTH THIS EVENING. THEN WINDS
STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT THRU
MIDDAY SAT WILL GENERALLY BE 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTBALE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN SCT TSRA THIS AFTERNOON THRU EARLY EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL/ENDING AT ORD/MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
A BROAD RIDGE OF HIGH PRESSURE EXTENDS FROM THE SOUTH HIGH PLAINS
THROUGH THE OHIO VALLEY. THIS RIDGE WILL SAG SOUTHEAST AND STALL
OUT OVER THE GULF COAST REGION LATE FRIDAY. MEANWHILE...LOW
PRESSURE OVER JAMES BAY WILL DEEPEN SLIGHTLY AS IT TRACKS EAST TO
NORTHERN QUEBEC...WHILE DRAGGING A COLD FRONT SOUTH ACROSS THE LAKE
FRIDAY. SOUTHWEST WINDS WILL INCREASE TO AROUND 30KT OVER MUCH OF
THE LAKE TODAY AS THE GRADIENT STRENGTHENS IN ADVACE OF THE COLD
FRONT. WINDS WILL THEN SHIFT TO MORE NORTHERLY BEHIND THE
FRONT...TEMPORARILY WEAKENING FOR A BRIEF PERIOD FRIDAY NIGHT. A
SECONDARY SURGE OF COOLER AIR WILL PUSH DOWN THE LAKE LATE FRIDAY
NIGHT AND SATURDAY STRENGTHENING THE WINDS TO AROUND 25KT WHILE
VEERING THROUGH NORTHERLY TO NORTHEASTERLY. AS HIGH PRESSURE
BUILDS FROM CENTRAL CANADA INTO THE UPPER MISSISSIPPI VALLEY AND
WESTERN GREAT LAKES...WINDS WILL THEN VEER EASTERLY OVER THE
LAKE...WHILE REMAINING RATHER BRISK.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 PM FRIDAY.
IN...HEAT ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM
FRIDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS TOPEKA KS
1237 PM CDT FRI JUL 19 2013
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI JUL 19 2013
EARLY THIS MORNING A BROAD UPPER LEVEL RIDGE AXIS EXTENDED FROM
COAST TO COAST ACROSS THE SOUTHERN CONUS. A CUT OFF UPPER LOW WAS
DRIFTING WEST ACROSS THE NORTHERN GULF OF MEXICO. A SECOND CUT OFF
LOW WAS DRIFTING SOUTHWEST INTO NORTHWEST MEXICO. AN UPPER LEVEL
TROUGH WAS MOVING EAST ACROSS THE NORTHERN PLAINS INTO THE UPPER
MIDWEST.
TODAY AND TONIGHT...THE UPPER RIDGE ACROSS THE WESTERN CONUS WILL
AMPLIFY CAUSING THE FLOW ACROSS THE CENTRAL PLAINS TO BECOME
SLIGHTLY MORE NORTHWESTERLY. THE BEST UPPER LEVEL ASCENT AHEAD OF
THE H5 TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL REMAIN WELL
NORTHEAST OF THE CWA. A WEAK COLD FRONT WILL MOVE SOUTHWARD ACROSS
NE INTO THE NORTHERN COUNTIES OF THE CWA BY 21Z. CONVERGENCE ALONG
THIS FRONT MAY CAUSE ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS THE NORTHERN COUNTIES OF THE CWA. THE 00Z GFS AND TWO
MESOSCALE MODELS...THE RAP AND NON-HYDROSTATIC WRF ARE SHOWING A
LINE OF SCATTERED TO NUMEROUS SHOWERS DEVELOPING AHEAD OF THE FRONT
AND PUSHING SOUTHEAST ACROSS THE REMAINDER OF THE CWA THROUGH THE
EVENING HOURS. WHILE THE ECMWF AND 00Z NAM SHOW ONLY ISOLATED
SHOWERS DEVELOPING ACROSS THE NORTHERN HALF OF THE CWA LATE FRIDAY
AFTERNOON AND EVENING. I`M LEANING MORE TOWARDS THE NAM AND ECMWF
SINCE THERE WILL BE LITTLE IN THE WAY OF UPPER LEVEL SUPPORT SINCE
THE MAIN H5 TROUGH WILL BE DIGGING SOUTHEAST ACROSS THE MIDWEST INTO
THE GREAT LAKES STATES. ATTM...I`LL KEEP THE LOW CHANCE POPS OF 25
TO 35 PERCENT ACROSS MUCH OF THE CWA TONIGHT. THE PRECIP SHOULD END
FROM NORTH TO SOUTH DURING THE EARLY MORNING HOURS OF SATURDAY AS
THE COLD FRONT PUSHES SOUTH OF THE CWA BY 12Z SAT.
SKIES WILL START OUT MOSTLY SUNNY ACROSS THE CWA WITH AN INCREASE IN
CU DURING THE AFTERNOON HOURS. HIGHS WILL REACH THE MID TO UPPER 90S
ACROSS THE CWA. SURFACE DEWPOINTS WILL DECREASE SLIGHTLY DURING THE
AFTERNOON HOURS AS THE BOUNDARY LAYER MIXES DEEPER ACROSS THE
PLAINS. I HAVE AFTERNOON DEWPOINTS IN THE LOWER TO MID 60S...WHICH
SHOULD KEEP HEAT INDICES NEAR THE HIGH TEMPERATURES IN THE UPPER
90S. HEAT INDICES MAY REACH AROUND 100 DEGREES ACROSS THE EASTERN
COUNTIES OF THE CWA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI JUL 19 2013
THE FRONT OR ITS REMNANTS WILL LIKELY REMAIN IN THE AREA THROUGH
EARLY NEXT WEEK. WITH WEST TO NORTHWEST FLOW ALOFT ALSO
DOMINATING...A SERIES OF SHORTWAVE TROUGHS WILL MOVE THROUGH THE
FLOW AND ACROSS THE COUNTY WARNING AREA THROUGH THE EXTENDED
PERIODS...ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE
STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS. ALTHOUGH WILL GO
WITH POPS THROUGH MOST OF THE FORECAST...THE BETTER CHANCES FOR MORE
ORGANIZED/HIGHER COVERAGE CONVECTIVE EVENTS OCCURS DURING TWO
PERIODS. THE FIRST WILL BE WITH A POSSIBLE MCS LATE SATURDAY
NIGHT/EARLY SUNDAY ACROSS MAINLY THE WESTERN CWA AND WITH THE
PASSAGE OF THE SHORTWAVE TROUGH ON THE NOSE OF VEERING LLVL FLOW AND
STRONGER WARM ADVECTION LATE SUNDAY INTO SUNDAY NIGHT. THIS SHOULD
BE FOLLOWED BY A PERIOD OF LOWER POP CHANCES INTO TUESDAY BEFORE
ANOTHER SHORTWAVE TROUGH PASSES AND FRONT MOVES THROUGH THE AREA
WITHIN ANOTHER REGION OF STRONGER WAA ALONG THE EASTERN PERIPHERY OF
A STRONG THERMAL AXIS. WITH BOUNDARY STILL IN THE AREA/OR JUST
SOUTH...WILL KEEP LOW POPS GOING PORTIONS OF THE CWA ON INTO
THURSDAY HOWEVER. TEMPERATURES OVER THE WEEKEND INTO NEXT WEEK WILL
BE CHALLENGING AS THE COUNTY WARNING AREA WILL OFTEN BE ON THE
EASTERN EDGE OF A STRONG LLVL THERMAL AXIS WITH THE LLVL FLOW
FREQUENTLY VEERED. HOWEVER...CLOUDS AND PERIODIC PRECIP CHANCES WILL
BE OFFSETTING FACTORS. FOR NOW...HIGHS WILL GENERALLY BE IN THE LOW
TO MID 90S THROUGH THE FCST. MONDAY AND TUESDAY WILL LIKELY BE THE
WARMEST DAYS WITH SOME UPPER 90S POSSIBLE IN THE WESTERN/SOUTHWEST
CWA. AT THIS POINT HEAT INDICES ON BOTH OF THOSE DAYS SHOULD BE IN
THE 98 TO 102 DEGREE RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1215 PM CDT FRI JUL 19 2013
VFR CONDITIONS AT KTOP/KFOE/KMHK FOR THE NEXT FORECAST PERIOD.
A GRADUAL FROPA LATE THIS AFTERNOON MAINLY AFTER 22Z WILL
VEER WINDS TO THE WEST AND THEN NORTHWEST BY 05Z AT KTOP/KFOE AND
KMHK BY 04Z. TIMING IS APPROXIMATE AS MODELS VARY SLIGHTLY ON THE
SPEED OF THE FRONT. WIDELY SCATTERED TSRA MAY BE POSSIBLE NEAR AND
ALONG THE FRONT AS IT PASSES. INSERTED VCTS FOR THIS
AFTERNOON/EARLY EVENING AT KMHK AND AFT 00Z AT KTOP/KFOE AS
COVERAGE OF TSRA IS LOW. EXPECT LIGHT AND VARIABLE WINDS AFT 04Z
AT TERMINALS WITH A BKN LAYER OF CIRRUS LINGERING THROUGH 18Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS JACKSON KY
223 PM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 223 PM EDT FRI JUL 19 2013
SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED...WITH THE
GREATEST CONCENTRATION OVER THE SW PART OF THE AREA...MOVING ENE.
BASED ON RADAR TRENDS...HAVE RAISED AFTERNOON POPS SLIGHTLY...BUT
STILL IN THE CHANCE CATEGORY.
UPDATE ISSUED AT 945 AM EDT FRI JUL 19 2013
FOG PERSISTED IN THE UPPER REACHES OF THE CUMBERLAND VALLEY AT MID
MORNING...BUT HAD DISSIPATED ELSEWHERE...AND SHOULD SOON BE GONE
EVERYWHERE. OUTSIDE OF FOG...SKIES WERE GENERALLY CLEAR AT MID
MORNING. HAVE DELAYED THE INCREASE IN CLOUD COVER AND PRECIP TODAY...
WITH WIDESPREAD CU DEVELOPMENT EXPECTED AROUND MID DAY...AND
SCATTERED SHOWERS AND THUNDERSTORMS TO SOON FOLLOW.
UPDATE ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGE TOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEW POINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PRE-FIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEW POINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 141 PM EDT FRI JUL 19 2013
THE CYCLE CONTINUES...WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AGAIN THIS AFTERNOON. LOCALIZED IFR CAN BE EXPECTED IN
THUNDERSTORMS AND THE HEAVIER SHOWERS. MOST OF THE PRECIP SHOULD THEN
DIE OUT THIS EVENING. FOG IS FORECAST OVERNIGHT...MAINLY IN VALLEYS.
THE EXTENT OF THE FOG TONIGHT WILL BE AFFECTED BY THE EXTENT OF RAIN
THIS AFTERNOON...WITH AREAS WHICH RECEIVE RAIN LATE IN THE DAY
EXPECTED TO HAVE MORE FOG. LOCALIZED IFR WILL OCCUR IN THE FOG. FOG
WILL DISSIPATE BY AROUND MID MORNING ON SATURDAY...WITH SCATTERED
SHOWERS AND THUNDERSTORMS THEN STARTING TO POP UP AGAIN TOWARD THE
END OF THE PERIOD. OUTSIDE OF PRECIP AND FOG...MAINLY VFR SHOULD
OCCUR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
141 PM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 945 AM EDT FRI JUL 19 2013
FOG PERSISTED IN THE UPPER REACHES OF THE CUMBERLAND VALLEY AT MID
MORNING...BUT HAD DISSIPATED ELSEWHERE...AND SHOULD SOON BE GONE
EVERYWHERE. OUTSIDE OF FOG...SKIES WERE GENERALLY CLEAR AT MID
MORNING. HAVE DELAYED THE INCREASE IN CLOUD COVER AND PRECIP TODAY...
WITH WIDESPREAD CU DEVELOPMENT EXPECTED AROUND MID DAY...AND
SCATTERED SHOWERS AND THUNDERSTORMS TO SOON FOLLOW.
UPDATE ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGE TOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEW POINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PRE-FIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEW POINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 141 PM EDT FRI JUL 19 2013
THE CYCLE CONTINUES...WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AGAIN THIS AFTERNOON. LOCALIZED IFR CAN BE EXPECTED IN
THUNDERSTORMS AND THE HEAVIER SHOWERS. MOST OF THE PRECIP SHOULD THEN
DIE OUT THIS EVENING. FOG IS FORECAST OVERNIGHT...MAINLY IN VALLEYS.
THE EXTENT OF THE FOG TONIGHT WILL BE AFFECTED BY THE EXTENT OF RAIN
THIS AFTERNOON...WITH AREAS WHICH RECEIVE RAIN LATE IN THE DAY
EXPECTED TO HAVE MORE FOG. LOCALIZED IFR WILL OCCUR IN THE FOG. FOG
WILL DISSIPATE BY AROUND MID MORNING ON SATURDAY...WITH SCATTERED
SHOWERS AND THUNDERSTORMS THEN STARTING TO POP UP AGAIN TOWARD THE
END OF THE PERIOD. OUTSIDE OF PRECIP AND FOG...MAINLY VFR SHOULD
OCCUR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS GRAY ME
644 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS EVENING ALONG WITH THE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS...ESPECIALLY ACROSS
NORTHERN AREAS WHERE A SEVERE THUNDERSTORM WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING. OTHERWISE VERY WARM AND MUGGY WEATHER
AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE OFF THE
COAST SATURDAY NIGHT WITH ANOTHER CHANCE OF STRONG TO SEVERE
THUNDERSTORMS DURING THE DAY SATURDAY. HIGH PRESSURE FOLLOWS THE
FRONT BRINGING COOLER AND LESS HUMID AIR TO THE REGION WHICH WILL
END OUR HEAT WAVE. THE HIGH WILL HOLD ON THROUGH TUESDAY. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WILL UPDATE TO ADJUST CHANCE OF SHOWERS AND THUNDERSTORMS BASED ON
LATEST RADAR. RADAR SHOWING LINE OF STRONG/SEVERE THUNDERSTORMS
MOVING THROUGH OUR NORTHERN MOST ZONES. A FEW SHOWERS JUST SOUTH
OF THE LINE WITH MOST OF THE FORECAST AREA DRY AT THIS TIME. THE
LINE OF STORMS WILL CONTINUE TO MOVE EAST WHILE OTHER SHOWERS AND
ISOLATED TO SCATTERED THUNDERSTORMS MAKE THERE WAY INTO THE REGION
LATER THIS EVENING.
HAVE ADDED PATCHY VALLEY FOG LATER TONIGHT DUE TO ANY RAINFALL
THAT OCCURS AND SATURATES THE BOUNDARY LAYER WHERE WE ALREADY HAVE
VERY HIGH DEW POINTS.
ALREADY UPDATED FORECAST TO ISSUE A SEVERE THUNDERSTORM WATCH FOR
OUR NORTHERN ZONES WHICH INCLUDE COOS COUNTY IN NH AND OXFORD...
FRANKLIN AND SOMERSET COUNTIES IN MAINE. THE WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING.
PREVIOUS DISCUSSION...
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH SATURDAY NIGHT/...SEVERE TSTM WATCH IN EFFECT
THROUGH 03Z THIS EVE FOR OUR NORTHERN ZONES WHICH IMPACTS HIE.
ISOLD TO SCT TSTMS COULD ALSO IMPACT REST OF FORECAST AREA
OVERNIGHT...RESULTING IN GUSTY WINDS AND LOWER CIG/VSBY. PATCHY F
COULD FORM OVERNIGHT ESPECIALLY WHERE RAIN FALLS...LEADING TO
LOCAL IFR/LIFR. TSTMS POSSIBLE SATURDAY WITH SEVERE WX AGAIN A
POSSIBILITY AS A COLD FRONT MOVES THROUGH LATER IN THE DAY. HIGH
PRESSURE BUILDS IN SATURDAY NIGHT BRINGING VFR WX, WITH SOME
PATCHY LATE NIGHT VALLEY F POSSIBLE, AS IT PUSHES TSTMS OUT TO
SEA.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...WILL UPDATE TO
INCREASE WINDS/GUSTS A BIT AND LOWER SEAS SOME FOR THIS EVENING
BASED ON LATEST BUOY REPORTS. SMALL CRAFT ADVISORY CONTINUES FOR
THE OUTER WATERS. THE PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS
TO BUILD THROUGH TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE
HEIGHTS ON SOUTHWEST FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN
AREAS BY MORNING. SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST
DURING THE DAY ON SATURDAY. WINDS LET UP LATE SATURDAY THEN SHIFT
TO NW AS THE FRONT MOVES OFFSHORE SATURDAY NIGHT.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
418 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS EVENING ALONG WITH THE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS...ESPECIALLY ACROSS
NORTHERN AREAS WHERE A SEVERE THUNDERSTORM WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING. OTHERWISE VERY WARM AND MUGGY WEATHER
AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE OFF THE
COAST SATURDAY NIGHT WITH ANOTHER CHANCE OF STRONG TO SEVERE
THUNDERSTORMS DURING THE DAY SATURDAY. HIGH PRESSURE FOLLOWS THE
FRONT BRINGING COOLER AND LESS HUMID AIR TO THE REGION WHICH WILL
END OUR HEAT WAVE. THE HIGH WILL HOLD ON THROUGH TUESDAY. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATED FORECAST TO ISSUE A SEVERE THUNDERSTORM WATCH FOR OUR
NORTHERN ZONES WHICH INCLUDE COOS COUNTY IN NH AND OXFORD...
FRANKLIN AND SOMERSET COUNTIES IN MAINE. THE WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING.
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...GUSTY SOUTHWEST WINDS WILL SUBSIDE SOMEWHAT LATE THIS
AFTERNOON. THUNDERSTORMS ARE POSSIBLE MAINLY THIS EVENING IN
NORTHERN AREAS... THOUGH THERE COULD BE A THUNDERSTORM OR TWO OVER
SOUTHERN NEW HAMPSHIRE THIS AFTERNOON. DESPITE CONTINUED HUMID
WEATHER... DO NOT EXPECT FOG TONIGHT. FOG LAST NIGHT WAS DUE TO
INCREASING DEW POINTS OVERNIGHT... WHILE THEY SHOULD HOLD STEADY
TONIGHT WITH WINDS STAYING IN THE 5 TO 10 KNOT RANGE.
THUNDERSTORMS ARE LIKELY ON SATURDAY DURING THE DAY AS A COLD
FRONT MOVES THROUGH.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY CONTINUES FOR THE OUTER WATERS.
ALTHOUGH 850 MB WIND SPEEDS ARE 30 TO 35 KNOTS... THE INVERSION
THAT LIKELY EXISTS OVER THE COOLER WATERS IN THIS ENVIRONMENT WILL
PREVENT WIND GUSTS FROM GETTING MUCH ABOVE 20 TO 25 KT. THE
PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS TO BUILD THROUGH
TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE HEIGHTS ON SOUTHWEST
FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN AREAS BY MORNING.
SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON
SATURDAY.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
415 PM EDT FRI JUL 19 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION ON SATURDAY...PRODUCING
POTENTIALLY SEVERE STORMS. BEHIND THIS FRONT...COOLER AND LESS
HUMID HIGH PRESSURE WILL BUILD IN...BRINGING AN END TO OUR HEAT
WAVE. THIS HIGH HOLD FOR SUNDAY THROUGH TUESDAY...WITH HIGHS IN THE
70S TO LOW 80S...AND OVERNIGHT LOWS IN THE 50S TO AROUND 60. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATED FORECAST TO ISSUE A SEVERE THUNDERSTORM WATCH FOR OUR
NORTHERN ZONES WHICH INCLUDE COOS COUNTY IN NH AND OXFORD...
FRANKLIN AND SOMERSET COUNTIES IN MAINE. THE WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING.
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...GUSTY SOUTHWEST WINDS WILL SUBSIDE SOMEWHAT LATE THIS
AFTERNOON. THUNDERSTORMS ARE POSSIBLE MAINLY THIS EVENING IN
NORTHERN AREAS... THOUGH THERE COULD BE A THUNDERSTORM OR TWO OVER
SOUTHERN NEW HAMPSHIRE THIS AFTERNOON. DESPITE CONTINUED HUMID
WEATHER... DO NOT EXPECT FOG TONIGHT. FOG LAST NIGHT WAS DUE TO
INCREASING DEW POINTS OVERNIGHT... WHILE THEY SHOULD HOLD STEADY
TONIGHT WITH WINDS STAYING IN THE 5 TO 10 KNOT RANGE.
THUNDERSTORMS ARE LIKELY ON SATURDAY DURING THE DAY AS A COLD
FRONT MOVES THROUGH.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY CONTINUES FOR THE OUTER WATERS.
ALTHOUGH 850 MB WIND SPEEDS ARE 30 TO 35 KNOTS... THE INVERSION
THAT LIKELY EXISTS OVER THE COOLER WATERS IN THIS ENVIRONMENT WILL
PREVENT WIND GUSTS FROM GETTING MUCH ABOVE 20 TO 25 KT. THE
PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS TO BUILD THROUGH
TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE HEIGHTS ON SOUTHWEST
FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN AREAS BY MORNING.
SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON
SATURDAY.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
319 PM EDT FRI JUL 19 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION ON SATURDAY...PRODUCING
POTENTIALLY SEVERE STORMS. BEHIND THIS FRONT...COOLER AND LESS
HUMID HIGH PRESSURE WILL BUILD IN...BRINGING AN END TO OUR HEAT
WAVE. THIS HIGH HOLD FOR SUNDAY THROUGH TUESDAY...WITH HIGHS IN THE
70S TO LOW 80S...AND OVERNIGHT LOWS IN THE 50S TO AROUND 60. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /TONIGHT/...
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...GUSTY SOUTHWEST WINDS WILL SUBSIDE SOMEWHAT LATE THIS
AFTERNOON. THUNDERSTORMS ARE POSSIBLE MAINLY THIS EVENING IN
NORTHERN AREAS... THOUGH THERE COULD BE A THUNDERSTORM OR TWO OVER
SOUTHERN NEW HAMPSHIRE THIS AFTERNOON. DESPITE CONTINUED HUMID
WEATHER... DO NOT EXPECT FOG TONIGHT. FOG LAST NIGHT WAS DUE TO
INCREASING DEW POINTS OVERNIGHT... WHILE THEY SHOULD HOLD STEADY
TONIGHT WITH WINDS STAYING IN THE 5 TO 10 KNOT RANGE.
THUNDERSTORMS ARE LIKELY ON SATURDAY DURING THE DAY AS A COLD
FRONT MOVES THROUGH.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY CONTINUES FOR THE OUTER WATERS.
ALTHOUGH 850 MB WIND SPEEDS ARE 30 TO 35 KNOTS... THE INVERSION
THAT LIKELY EXISTS OVER THE COOLER WATERS IN THIS ENVIRONMENT WILL
PREVENT WIND GUSTS FROM GETTING MUCH ABOVE 20 TO 25 KT. THE
PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS TO BUILD THROUGH
TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE HEIGHTS ON SOUTHWEST
FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN AREAS BY MORNING.
SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON
SATURDAY.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
SYNOPSIS...CEMPA
NEAR TERM...KIMBLE
SHORT TERM...KIMBLE
LONG TERM...CEMPA
AVIATION...CEMPA/KIMBLE
MARINE...CEMPA/KIMBLE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
548 PM EDT FRI JUL 19 2013
LATEST UPDATE...
MESOSCALE DISCUSSION
.MESOSCALE DISCUSSION...
ISSUED AT 545 PM EDT FRI JUL 19 2013
I BELIEVE WE STILL HAVE SOME POTENTIAL FOR A LINE OF STRONG TO
SEVERE STORMS TO DEVELOP JUST AHEAD OF THE COLD FRONT AS IT MOVES
SLOWLY SOUTH THROUGH OUR CWA EARLY TONIGHT. CURRENTLY THERE ARE
SCATTERED STORMS AHEAD OF THE FRONT OVER NORTHERN LOWER. HOWEVER
THERE IS A SPEED MAX (SEEN ON THE WATER VAPOR IMAGE LOOP) OVER
CNTL MN/WI AT 532 PM HEADING TOWARD NORTHERN LOWER MICHIGAN. THAT
WILL BE OVER NORTHERN LOWER MICHIGAN IN THE 8 PM TO MIDNIGHT TIME
FRAME. I EXPECT THE LINE TO FILL IN WITHIN THE NEXT HOUR OR TWO.
THEN CONTINUE TO MOVE SOUTH SIMILAR TO THE 20Z HRRR SHOWS IT
DOING. AS A RESULT I PLAN ON KEEPING OUR SEVERE THUNDERSTORM WATCH
IN PLACE FOR NOW.
&&
.SYNOPSIS...
ISSUED AT 356 PM EDT FRI JUL 19 2013
A COLD FRONT WILL PRESS THROUGH SOUTHWEST LOWER MICHIGAN TONIGHT
WHICH WILL BE PRECEDED BY SHOWERS AND THUNDERSTORMS. SOME OF THE
STORMS THIS EVENING MAY BE SEVERE WITH DAMAGING WINDS AND TORRENTIAL
RAINS. THE SHOWERS AND STORMS WILL MOVE SOUTH INTO INDIANA AND OHIO
SATURDAY MORNING. A REFRESHING COOLER AND DRIER AIR MASS WILL SETTLE
INTO THE STATE FOR THE WEEKEND. HIGHS WILL BE CLOSER TO NORMALS FOR
THIS TIME OF YEAR WITH LOWER 80S ON SATURDAY AND AROUND 80 ON SUNDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 356 PM EDT FRI JUL 19 2013
STILL A COMPLEX CONVECTIVE EVOLUTION IN PLACE...WITH A PRE FRONTAL
CONVERGENCE ZONE RESULTING IN SCATTERED THUNDERSTORM DEVELOPMENT AT
THIS TIME FROM NEAR HOLLAND EAST TO IONIA. THESE STORMS WILL
CONTINUE TO DEVELOP AS MIXED LAYER CAPE VALUES ARE ON THE ORDER OF
2000 J/KG AT THIS TIME. TWO MAIN CORRIDORS OF INSTABILITY ARE IN
PLACE ONE POOLED NEAR THE FRONT OFF TO THE NORTH WHICH STRETCHES
FROM NORTHERN LAKE MICHIGAN INTO CENTRAL WISCONSIN. THE OTHER AREA
OF EVEN HIGHER INSTABILITY IS NOSED INTO SOUTH CENTRAL LOWER
MICHIGAN FROM GRR SOUTH AND EAST. THIS ZONE IS IN PLAY DUE TO THE
FACT THAT THE SOUTHWEST FLOW IS NOT OFF THE LAKE HERE.
DYNAMICS REMAIN A FACTOR AS THE MID LEVEL SHORTWAVE TROUGH EDGES IN
ALONG WITH AN ENTRANCE REGION TO A 250MB JET STREAK. REALLY ALL
INGREDIENTS ARE IN PLACE...MOISTURE...INSTABILITY AND LIFT. ENVISION
THE CURRENT LINE CONTINUING TO DEVELOP WITH SOME SEVERE WIND GUSTS
EMBEDDED. THE FRONT TO THE NORTH WILL BE THE WILD CARD BUT EXPECT TO
SEE A LINEAR LINE OF STORMS FORM ALONG IT AND PROGRESS SOUTH. THESE
STORMS MAY BE MOVING INTO CENTRAL LOWER MICHIGAN IN THE 7-9PM TIME
RANGE. SEVERE WEATHER WITH THESE IS POSSIBLE BUT THERE IS A SOLID
LAKE SHADOW OF WEAKER INSTABILITY THERE.
MAIN THREAT CONTINUES TO BE DAMAGING WINDS AS STRONG SYNOPTIC SCALE
FLOW IS IN PLACE IN THE 850-500MB LAYER.
COOLER AND DRIER AIR WILL BRING QUIET WEATHER SATURDAY INTO SUNDAY.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 356 PM EDT FRI JUL 19 2013
COOLER PATTERN TO PERSIST WITH NEAR NORMAL TO SLIGHTLY BELOW NORMAL
TEMPERATURES LOOKING MORE LIKELY THROUGH NEXT WEEK. THIS MEANS HIGHS
IN THE UPPER 70S TO LOWER 80S WITH LOWS IN THE LOWER 60S. THERE WILL
BE SCATTERED CHANCES FOR SHOWERS AND THUNDERSTORMS ESPECIALLY DURING
THE FIRST HALF OF NEXT WEEK...BUT OVERALL NO ORGANIZED SIGNIFICANT
WEATHER EXPECTED MONDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 148 PM EDT FRI JUL 19 2013
GENERALLY VFR CIGS/VSBYS EXPECTED THROUGH THE PERIOD. THERE MAY BE
SHOWERS PERHAPS A TSRA IN THE VICINITY OF THE TAF SITES LATER THIS
AFTERNOON. HOWEVER LATEST VIS LOOP SHOWS WEST WIND HAVE SCOURED
OUT THE CU ACROSS MUCH OF THE AREA. THINK THE BETTER CHANCE OF
STORMS WILL BE AFTER 10 PM WHEN THE MAIN COLD FRONT STARTS TO MOVE
SOUTH ACROSS THE LOWER PENINSULA. NOT CONVINCED WE/LL SEE A SOLID
LINE OF STORMS ALONG THE FRONT SO LEFT THE VCTS COMMENT IN THE TAFS.
&&
.MARINE...
ISSUED AT 356 PM EDT FRI JUL 19 2013
A COMPLEX MARINE SCENARIO IS IN PLACE WITH AN ONGOING HIGH WAVE
EVENT IN PROGRESS. WAVES OF 4 TO 7 FEET ARE COMMON PLACE IN THE
NEARSHORE AREA AT THIS TIME. THE WIND WILL DIMINISH TONIGHT AND THE
WAVES WILL DAMPEN OUT AS WELL...SUBSIDING BELOW SMALL CRAFT ADVISORY
CRITERIA AFTER MIDNIGHT. A HIGH SWIM HAZARD RISK WILL CONTINUE
THROUGH SUNSET.
THE COMPLICATING FACTOR IS IT APPEARS ANOTHER HIGH WAVE EVENT WILL
FOLLOW QUICKLY ON THE HEELS OF THIS ONE TOMORROW AFTERNOON IN THE
NORTHERLY FLOW BEHIND THE COLD FRONT. WILL HOLD OFF ON ISSUING A
BEACH HAZARDS STATEMENT AND SMALL CRAFT ADVISORY FOR SATURDAY INTO
SATURDAY NIGHT...LETTING THIS ONE END FIRST. A CLOSER LOOK WILL BE
TAKEN AT TOMORROWS EVENT BY THE MID SHIFT.
&&
.HYDROLOGY...
ISSUED AT 356 PM EDT FRI JUL 19 2013
LOCAL FLOODING POTENTIAL WILL CONTINUE UNTIL THE FRONT AND THEREFORE
STORM THREAT IS SOUTH OF THE AREA. BY SATURDAY MORNING THE FRONT
SHOULD BE SOUTH OF SOUTHWEST LOWER MICHIGAN. ANY STORMS THIS EVENING
AND TONIGHT GIVEN A VERY MOIST AIRMASS IN PLACE WILL BE CAPABLE OF
TORRENTIAL DOWNPOURS. LOCALIZED FLOODING IS VERY POSSIBLE IN AN AIR
MASS SUCH AS THIS. WIDESPREAD HEAVY AREAL RAINFALL IS NOT EXPECTED
HOWEVER. SO...A FLASH FLOOD TYPE THREAT WILL EXIST THIS EVENING AND
TONIGHT BUT WIDESPREAD RIVER ISSUES ARE NOT ANTICIPATED GIVEN THE
LOCAL NATURE OF THE HEAVY RAINS. A COOLER AND DRIER AIR MASS WILL
PUSH INTO THE AREA FOR SATURDAY AND SUNDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 11 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ037>040-043>046-
050>052-056>059-064>067-071>074.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LMZ844>849.
&&
$$
MESOSCALE...WDM
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...MACZKO
AVIATION...93
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
203 PM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM CDT FRI JUL 19 2013
OUR MPX WRF AND HOP WRF ARE ON SIMILAR PATHS WITH THE SHOWER AND
THUNDERSTORM ACTIVITY EXITING OUR AREA BY 12Z. FOR TODAY...A BREAK
FROM THE HEAT AND HUMIDITY WILL BE NOTED WITH SOME SCATTERED
CLOUDS...EXCEPT FOR SOUTHWEST MN WHICH MAY BE CLOUD FREE. VERY DRY
AIR ABOVE 6000 FEET WILL CONTINUE WORKING ITS ITS WAY INTO WESTERN
MN. THERE IS SOME LOW LEVEL MOISTURE ACROSS EASTERN MN AND WESTERN
WI. THE RAP KEEPS THIS MOISTURE IN PLACE UNTIL MID AFTERNOON. SHOULD
BE PLENTY OF MIXING SO DO NOT EXPECT MORE THAN SCATTERED
CLOUDS...EXCEPT SW MN WHERE IT MAY BE CLEAR. MAY BE CLEAR AFTER 21Z
IN MOST AREAS AS DRIER AIR FILTERS IN. OVERNIGHT A SECONDARY COLD
FRONT USHERS IN COOLER AIR AND BY SATURDAY MORNING A DISTURBANCE
MOVES TOWARD WESTERN MN WITH AN INCREASE IN MOISTURE. NO
PRECIPITATION EXPECTED THROUGH 12Z SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM CDT FRI JUL 19 2013
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE RIDGING OVER THE
ROCKIES...WITH EPISODIC IMPULSES PARADING ACROSS THE NORTHERN CONUS.
THE FIRST OF THESE SHORTWAVES HAS BEEN CONSISTENTLY PROGGED TO
ARRIVE ON SATURDAY NIGHT INTO SUNDAY BY DETERMINISTIC AND ENSEMBLE
SOLUTIONS. FAIRLY IMPRESSIVE LIFT FROM 305-310K IS PROGGED TO
BLOSSOM OVER THE AREA BETWEEN 06Z AND 12Z SUNDAY AS 925-850 MOISTURE
TRANSPORT NOSES INTO SOUTHERN MN. HAVE INCLUDED 50-60 POPS FOR THIS
TIME FRAME.
NORTHWEST FLOW PERSISTS THROUGH THE BEGINNING OF NEXT WEEK...WHICH WILL
NECESSITATE THE INCLUSION OF 20-30 POPS FOR A LONG DURATION. THE
TUESDAY INTO WEDNESDAY TIME FRAME IS TRENDING DRIER HOWEVER...AS
DRY SURFACE HIGH PRESSURE BUILDS IN...SO MAY BE ABLE TO SHED
SHOWER AND THUNDERSTORM CHANCES FOR THOSE DAYS.
WEDNESDAY NIGHT INTO FRIDAY LOOK WET AGAIN HOWEVER....AS SHORTWAVE
ENERGY CHANNELS THROUGH THE WESTERN PERIPHERY OF THE ONTARIO LOW.
TEMPERATURES WILL REMAIN RELATIVELY STATIC THROUGH THE EXTENDED
PERIOD...WITH HIGHS GENERALLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 134 PM CDT FRI JUL 19 2013
NO PROBLEMS IN THE SHORT TERM. WE SHOULD LARGELY REMAIN DRY WITH
VFR CONDITIONS TONIGHT AND MOST OF THE DAY TOMORROW. YOU WILL
NOTICE A SMALL AREA OF THUNDERSTORMS NEAR THE ND/CANADIAN BORDER
THIS AFTERNOON. IT IS POSSIBLE SOME OF THIS ACTIVITY WILL MAKE IT
INTO WESTERN AND CENTRAL MN TONIGHT. INCLUDED A VCSH AT KAXN AND
KRWF...BUT SHOWERS WILL BE WIDELY SCATTERED IF THEY OCCUR AT ALL.
WE MAY END UP SEEING A FEW MORE MID CLOUDS LATE TONIGHT.
KMSP...
AS MENTIONED ABOVE...WE HAVE A GOOD CHANCE OF REMAINING DRY
TONIGHT AND AT WORSE THE AIRPORT WILL SEE A LIGHT SHOWER OR A FEW
SPRINKLES JUST BEFORE SUNRISE. VFR IS EXPECTED.
/OUTLOOK FOR KMSP/
SAT NIGHT...MAINLY VFR. SLGT CHC -SHRA/-TSRA. NW WINDS 5-10 KTS.
SUN...MAINLY VFR. CHC -SHRA/-TSRA. NE WINDS 5-10 KTS.
MON...MAINLY VFR. CHC -SHRA/TSRA. SE-S WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...LS
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS BUFFALO NY
348 PM EDT FRI JUL 19 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL DROP ACROSS THE REGION TONIGHT...WHICH
WILL LINGER INTO SATURDAY. A COLD FRONT WILL DROP ACROSS THE
REGION SATURDAY...BRINGING MUCH COOLER CONDITIONS FOR SUNDAY AND
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THIS AFTERNOON HOT AND WINDY CONDITIONS WILL
PERSIST ACROSS THE REGION. AN UPPER LEVEL TROF SOUTH OF HUDSON BAY
WILL DIVE TOWARD THE UPPER LAKES THROUGH TONIGHT...PUSHING AN
ASSOCIATED COLD FRONTAL BOUNDARY TOWARD OUR REGION. WHILE THE
FRONT ITSELF WILL REMAIN WELL UPSTREAM...THIS WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. THE BUFFALO VAD WIND PROFILE
ALREADY SHOWS 40 KNOT WINDS AT 925 MB...WITH THESE WINDS FORECAST
TO INCREASE SLIGHTLY FROM WEST TO EAST THROUGH THIS EVENING.
THESE SOUTHWEST WINDS SHOULD FAIRLY READILY MIX TO THE
SURFACE...WITH THE LAKE BREEZE ENHANCING THIS FLOW TO THE
NORTHEAST OF THE LAKES. THE WINDIEST CONDITIONS SHOULD BE ACROSS
THE NIAGARA FRONTIER AND IMMEDIATE LAKE ERIE SHORELINE...WHICH
INCLUDES THE BUFFALO METRO AREA. GUSTS SHOULD GENERALLY RUN IN THE
40 TO 45 MPH RANGE IN THIS AREA...WITH PEAK GUSTS LIKELY TO TOP
OUT NEAR 50 MPH. EXPECT THAT WITH THE FULL FOLIAGE...THIS WILL
RESULT IN A FEW DOWNED TREE LIMBS...WITH SOME SPOTTY POWER OUTAGES
POSSIBLE. ELSEWHERE WILL BE BREEZY AS WELL...BUT INTERIOR
LOCATIONS WILL GENERALLY LESS WINDY.
THE OTHER BIG ISSUE WILL SIMPLY BE THE HOT WEATHER. THE SW FLOW
OFF THE LAKE SHOULD HOLD TEMPERATURES 90 IN THE BUFFALO
AREA...BUT ROCHESTER EASTWARD THIS FLOW WILL DOWNSLOPE AND ADD A
FEW MORE DEGREES TO THE ALREADY HOT WEATHER. FOR MANY THIS WILL BE
THE HOTTEST DAY SO FAR...WITH HIGHS IN THE MID 90S. THIS COMBINED
WITH DEW POINTS IN THE LOWER 70S WILL RESULT IN HEAT INDEX VALUES
OVER 100 FOR ROCHESTER AND IN THE NORTHERN GENESEE VALLEY AND
FINGER LAKES REGIONS. OTHERWISE...EXPECT WIDELY SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AND
EASTERN LAKE ONTARIO REGION TO DISSIPATE TOWARD SUNSET...AS DAYTIME
HEATING DIMINISHES AND AS WINDS INCREASE MIXING AND EXPAND THE
LAKE SHADOWING.
FOR TONIGHT AND INTO SATURDAY...THE FOCUS WILL SHIFT TO THE
POTENTIAL FOR SEVERE WEATHER AND FOR LOCALLY HEAVY RAINFALL. THIS WILL
LIKELY COME IN TWO WAVES. THE FIRST CAN ALREADY BE SEEN CLEARLY
THROUGH MID-AFTERNOON...WITH THIS AREA ASSOCIATED WITH A LINE OF
THUNDERSTORMS ACROSS LAKE HURON AND EXTENDING EAST INTO SOUTHERN
ONTARIO PROVINCE. THIS INITIAL WAVE WILL TRACK TOWARD OUR REGION...BUT
GIVEN THE STRONG SW FLOW ACROSS THE LAKES WILL PROBABLY CAUSE IT TO
WEAKEN AS IT TRIES TO MOVE INTO OUR REGION. HIGHER RESOLUTION
GUIDANCE IS IN GENERAL AGREEMENT WITH THE NAM/RGEM/HRRR ALL
SHOWING THIS GENERAL TREND. THERE IS STILL A POSSIBILITY THAT THIS
WILL HOLD TOGETHER LONG ENOUGH TO HAVE SOME IMPACT ON OUR
CWA...WITH THE SAINT LAWRENCE RIVER AND NORTH COUNTRY AND POSSIBLY
PORTIONS OF THE NIAGARA FRONTIER THE AREAS TO WATCH. IT WILL BE
TRICKY...SINCE THE LINE WILL PROBABLY BE QUITE IMPRESSIVE JUST
UPSTREAM OF THE LAKE BREEZE...WITH BOWING LINE SEGMENTS CAPABLE OF
PRODUCING DAMAGING WINDS. THIS INITIAL LINE WILL IMPACT OUR
REGION BETWEEN 700 PM AND 1000 PM.
BEHIND THIS...IS A SECONDARY LINE OF THUNDERSTORMS DEVELOPING
ALONG WHAT APPEARS TO BE A PRE-FRONTAL TROF WIND SHIFT BOUNDARY.
00/12Z RUNS OF THE NAM/RGEM AND RECENT RUNS OF THE HRRR CONTINUE
TO SUGGEST THAT THIS AREA WILL EXPAND...AND EVENTUALLY DROP ACROSS
OUR REGION DURING THE OVERNIGHT HOURS. THE LATER TIMING...AND
CLOSER PROXIMITY TO THE SHORTWAVE WILL MAKE THIS FEATURE MORE
LIKELY TO HOLD TOGETHER AS IT DROPS ACROSS THE LAKES AND ACROSS
WESTERN NEW YORK LATE TONIGHT AND INTO SATURDAY MORNING. THIS
TIMING IS CLIMATOLOGICALLY NOT FAVORABLE FOR SEVERE WEATHER...BUT
GIVEN THE SIGNIFICANT AMOUNT OF NIGHTTIME INSTABILITY...AND STILL
A FAIR AMOUNT OF SHEAR...IT WILL BEAR A RADAR WATCH IF IT DOES
INDEED DEVELOP AS FORECAST.
IN ADDITION TO THE SEVERE WEATHER THREAT...THERE WILL ALSO BE A
RISK FOR LOCALLY HEAVY DOWNPOURS. PRECIPITABLE WATER VALUES WILL
BE 1.75 TO 2.00 INCHES...AND WHILE STORMS WILL LIKELY BE
MOVING...LARGE AREAS OF CONVECTION OR BRIEF TRAINING COULD QUICKLY
ADD UP AND LEAD TO LOCALIZED FLOODING.
ON SATURDAY...EXPECT MOST OF THE SHOWERS AND THUNDERSTORM ACTIVITY
TO SLIDE TO THE SOUTH AND EAST OF THE AREA LATE MORNING AND INTO
THE AFTERNOON HOURS. THE ACTUAL FRONTAL BOUNDARY WILL NOT CROSS
UNTIL LATER IN THE DAY...BUT MUCH DRIER AIR WILL MOVE IN BEHIND
THE PRE-FRONTAL TROF WITH ONLY MARGINAL CHANCE FOR ANY SHOWERS OR
THUNDERSTORMS ALONG THE FRONT ITSELF WHICH WILL CROSS LATE IN THE
DAY SATURDAY. WITH COOLER AIR MOVING IN AND LINGERING
PRECIPITATION...TEMPERATURES WILL BE NOTABLY COOLER ON
SATURDAY...WITH HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
BY SATURDAY EVENING...MOST OF THE 12Z GUIDANCE PACKAGES ARE IN GOOD
AGREEMENT THAT THE COLD FRONTAL ZONE AND THE BULK OF ITS ASSOCIATED
PRECIPITATION WILL HAVE SLIPPED TO OUR SOUTH...SAVE FOR THE NAM
WHICH IS A SLOWER OUTLIER. AS THIS PARTICULAR MODEL HAS SHOWN SOME
RUN-TO-RUN INCONSISTENCIES WITH THE TIMING OF THE FRONT OVER THE
PAST DAY OR SO...WILL DISREGARD IT IN FAVOR OF THE FASTER GFS/
GEM/ECMWF CONSENSUS AND OUR EXISTING CONTINUITY...ALL OF WHICH
ADVERTISE A GENERALLY DRY NIGHT. IN THE WAKE OF THE FRONT...A HIGHLY
ANTICIPATED COOLER AND DRIER AIRMASS WILL SPREAD SOUTH ACROSS OUR
AREA THROUGH THE COURSE OF THE NIGHT...FINALLY BRINGING SOME MUCH
WELCOMED RELIEF FROM THE TROPICAL HEAT AND HUMIDITY LEVELS OF THE
PAST WEEK. EXPECT OVERNIGHT LOWS TO DROP TO THE MID 50S TO LOWER
60S...WHILE SURFACE DEWPOINTS FALL BACK TO MUCH MORE COMFORTABLE
LEVELS IN THE 50S.
WITH THE WATERS OF THE LOWER GREAT LAKES NOW IN THE MID TO UPPER 70S
/OR AROUND +25C/...AND THE INCOMING COOLER AIRMASS EVENTUALLY
FEATURING 850 MB TEMPS OF AROUND +10C BY LATER IN THE NIGHT...WE MAY
WELL SEE SOME LAKE EFFECT CLOUDINESS DEVELOP SOUTH OF THE LAKES
OVERNIGHT...THOUGH THE INCOMING AIRMASS WILL LIKELY REMAIN TOO DRY
AND FEATURE TOO LOW OF A SUBSIDENCE INVERSION TO SUPPORT ANY LAKE
EFFECT SHOWERS.
SUNDAY AND SUNDAY NIGHT...SURFACE HIGH PRESSURE WILL SETTLE DIRECTLY
ACROSS THE LOWER LAKES AND NEW YORK STATE IN THE WAKE OF THE COLD
FRONT. COUPLED WITH STRONG MIDSUMMER DIURNAL EFFECTS...THIS SHOULD
RESULT IN ANY LAKE EFFECT CLOUDS FROM SATURDAY NIGHT BREAKING UP
DURING THE COURSE OF SUNDAY MORNING...LEADING TO A DECENT AMOUNT OF
SUNSHINE EVERYWHERE FOR THE AFTERNOON. MEANWHILE...850 MB TEMPS
RANGING FROM +9C NORTH TO +13C SOUTH SHOULD SUPPORT RATHER PLEASANT
HIGHS IN THE MID TO UPPER 70S...WHILE DEWPOINTS CONTINUE TO LOWER TO
THE 50-55 DEGREE RANGE WITH DIURNAL MIXING. THE COOLER AND QUIET
WEATHER WILL THEN CONTINUE INTO SUNDAY NIGHT...WHEN LOWS SHOULD
RANGE THROUGH THE 50S IN MOST LOCATIONS...WITH SOME UPPER 40S EVEN
POSSIBLE ACROSS PORTIONS OF THE NORTH COUNTRY. WITH THE LOW LEVEL
FLOW VEERING MORE EASTERLY...DO NOT EXPECT LAKE EFFECT CLOUDINESS TO
BE A PROBLEM FOR SUNDAY NIGHT...THOUGH THERE WILL PROBABLY BE SOME
INCREASE IN MID/HIGH CLOUDS OVERNIGHT IN ADVANCE OF A MODEST
SHORTWAVE TROUGH THAT WILL BE WORKING INTO THE CENTRAL GREAT LAKES.
MONDAY AND MONDAY NIGHT...THE SURFACE HIGH WILL SLIDE EAST ACROSS
NEW ENGLAND AND OUT TO SEA...WHILE THE AFOREMENTIONED SHORTWAVE
TROUGH TO OUR WEST SETTLES ACROSS THE LOWER LAKES AND NY/PA...WHILE
ALSO SPAWNING SOME SEMBLANCE OF A WEAK SURFACE REFLECTION. WHILE THE
VARIOUS GUIDANCE PACKAGES STILL DIFFER WITH RESPECT TO HOW FAST
THIS SYSTEM ARRIVES AND EXACTLY HOW WELL DEVELOPED IT WILL BE...ALL
HAVE CONTINUED THE RECENT TREND TOWARD A FASTER AND SOMEWHAT MORE
DEVELOPED SYSTEM...WITH A PLUME OF DEEPER MOISTURE AND WEAK TO
MODEST ISENTROPIC LIFT EVENTUALLY ADVECTING INTO OUR AREA BETWEEN
MONDAY AFTERNOON AND MONDAY NIGHT. WITH THIS AND OUR EXISTING
CONTINUITY OF A TOTALLY DRY FORECAST BOTH IN MIND...HAVE ELECTED TO
GRADUALLY INTRODUCE SOME LOWER CHANCE POPS INTO AREAS SOUTH OF LAKE
ONTARIO MONDAY AFTERNOON...BEFORE BRINGING HIGHER CHANCE RANGE POPS
INTO THE ENTIRE AREA MONDAY NIGHT. THE HIGHEST PRECIPITATION CHANCES
WILL BE FOCUSED ACROSS OUR FINGER LAKES AND NORTH COUNTRY ZONES...
WHICH WILL BE CLOSEST TO THE BEST AREA OF DEEPER MOISTURE AND
ISENTROPIC LIFT. TEMPS THROUGH THIS LATTER PORTION OF THE PERIOD
WILL RETURN TO MIDSUMMER NORMS GIVEN THE WEAK WARM AIR ADVECTION
PATTERN...WITH DAYTIME HIGHS OF AROUND 80 EXPECTED ON MONDAY...
FOLLOWED BY LOWS IN THE LOWER TO MID 60S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
IN THE LONG TERM PORTION OF THE FORECAST...THE LARGE-SCALE WEATHER
PATTERN ACROSS NORTH AMERICA WILL REVERT TO ONE WE HAVE BEEN MORE
FAMILIAR WITH FOR THE BULK OF THE SPRING AND SUMMER...THAT OF A
BROAD RIDGE OVER THE ROCKIES AND WESTERN PLAINS...WITH A
CORRESPONDING BROAD DOWNSTREAM TROUGH DEVELOPING OVER THE GREAT
LAKES AND NORTHEAST. THIS CHANGE IN THE PATTERN WILL RESULT IN AN
EXTENDED PERIOD OF MORE NORMAL SUMMERTIME TEMPERATURES FOR OUR
REGION...WITH DAILY HIGHS AVERAGING WITHIN A FEW DEGREES OF 80 EACH
DAY...AND NIGHTTIME LOWS GENERALLY RANGING IN THE LOWER TO MID 60S.
WITH RESPECT TO PRECIPITATION CHANCES...THE FORECAST PICTURE REMAINS
CONSIDERABLY MORE MUDDLED. UNDER THE EXPECTED LARGE-SCALE FLOW
REGIME...NUMEROUS PIECES OF SHORTWAVE ENERGY SHOULD ROTATE THROUGH
THE DEVELOPING TROUGH AND LEAD TO PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS...HOWEVER THE MEDIUM RANGE GUIDANCE REMAINS ALL OVER
THE MAP WITH RESPECT TO THE TIMING AND STRENGTH OF THESE FEATURES.
WITH THIS IN MIND...HAVE JUST CONTINUED TO BROADBRUSH SOME LOW
CHANCE POPS ACROSS THE ENTIRE PERIOD FOR NOW...AND WILL WAIT UNTIL
BETTER MODEL AGREEMENT DEVELOPS BEFORE TRYING TO PROVIDE MORE
REFINED/DETAILED PRECIPITATION PROBABILITIES AND TIMING. ALL THIS
SAID...THIS PERIOD LOOKS TO BE FAR FROM A WASHOUT AT THIS TIME...
WITH ANY SHOTS OF SHOWERS/STORMS LIKELY TO ALTERNATE WITH FREQUENT
DRY PERIODS.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
FOR THE 18Z TAF CYCLE...GUSTY SW WINDS TO BE THE MAIN IMPACT FOR
THIS AFTERNOON...WITH BUF/IAG/ROC/ART ALL SEEING PREVAILING GUSTS
IN THE 30 TO 35 KT RANGE. WIDELY SCATTERED THUNDERSTORMS MAY
BRIEFLY IMPACT JHW.
AFTER THIS...A LINE OF THUNDERSTORMS WILL APPROACH FROM THE WEST
23Z. THIS AREA WILL PROBABLY WEAKEN AS IT MOVES INTO OUR
REGION...BUT MAY HOLD TOGETHER LONG ENOUGH TO IMPACT IAG/ART...AND
POSSIBLY BUF/ROC DURING THE EVENING HOURS. STEADIER THUNDERSTORMS
ARE LIKELY LATE TONIGHT AS A LARGER AREA IS FORECAST TO DROP
ACROSS THE REGION. ALL THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND
WIND SHIFTS...WITH HEAVY RAIN LOWERING VSBY TO 1SM.
STORMS WILL DROP FROM N-S LATE TONIGHT AND INTO SATURDAY
MORNING...WITH CONDITIONS IMPROVING TO VFR.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY MORNING...VFR.
MONDAY AFTERNOON THROUGH WEDNESDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS/THUNDERSTORMS.
&&
.MARINE...
WINDS HAVE PICKED UP THROUGH THE EARLY AFTERNOON HOURS ACROSS MOST
OF THE WATERS...WITH WINDS STRONGEST NEAR THE LAKE SHORES. THESE
WILL CONTINUE THROUGH THIS EVENING...AS A STRONG LOW LEVEL JET
REMAINS ACROSS THE REGION. WINDS WILL DIMINISH FROM WEST TO EAST
LATER TONIGHT...MORE QUICKLY ACROSS AREAS NEAR LAND WHERE THE LOSS
OF DAYTIME HEATING WILL RESULT IN LESS MIXING. WAVES ON THE
NORTHEAST SHORES WILL TAKE A BIT TO DROP OFF ON BOTH OF THE LAKES.
THE OTHER ISSUE FOR THIS EVENING AND TONIGHT WILL BE THE POTENTIAL
FOR STRONG TO SEVERE THUNDERSTORMS ON THE WATERS.
WINDS WILL DIMINISH SATURDAY AND ONWARD WITH NO HEADLINES ANTICIPATED.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030-042-043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...APFFEL
MARINE...APFFEL
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
302 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THIS AFTERNOON HOT AND WINDY CONDITIONS WILL
PERSIST ACROSS THE REGION. AN UPPER LEVEL TROF SOUTH OF HUDSON BAY
WILL DIVE TOWARD THE UPPER LAKES THROUGH TONIGHT...PUSHING AN
ASSOCIATED COLD FRONTAL BOUNDARY TOWARD OUR REGION. WHILE THE
FRONT ITSELF WILL REMAIN WELL UPSTREAM...THIS WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. THE VAD WIND PROFILE ALREADY SHOWS
40 KNOT WINDS AT 925 MB...AND THESE ARE FORECAST TO INCREASE A BIT
MORE THROUGH SUNSET FROM WEST TO EAST. THESE SOUTHWEST WINDS
SHOULD FAIRLY READILY MIX TO THE SURFACE...WITH THE LAKE BREEZE
ENHANCING THIS FLOW TO THE NORTHEAST OF THE LAKES. THE WINDIEST
CONDITIONS SHOULD BE ACROSS THE NIAGARA FRONTIER AND IMMEDIATE LAKE
ERIE SHORELINE...WHICH INCLUDES THE BUFFALO METRO AREA. GUSTS
SHOULD GENERALLY RUN IN THE 40 TO 45 MPH RANGE IN THIS AREA...WITH
PEAK GUSTS LIKELY TO TOP OUT NEAR 50 MPH. EXPECT THAT WITH THE
FULL FOLIAGE...THIS WILL RESULT IN A FEW DOWNED TREE LIMBS...WITH
SOME SPOTTY POWER OUTAGES POSSIBLE. ELSEWHERE WILL BE BREEZY AS
WELL...BUT INTERIOR LOCATIONS WILL GENERALLY LESS WINDY.
THE OTHER BIG ISSUE WILL SIMPLY BE THE HOT WEATHER. THE SW FLOW
OFF THE LAKE SHOULD HOLD TEMPERATURES 90 IN THE BUFFALO
AREA...BUT ROCHESTER EASTWARD THIS FLOW WILL DOWNSLOPE AND ADD A
FEW MORE DEGREES TO THE ALREADY HOT WEATHER. FOR MANY THIS WILL BE
THE HOTTEST DAY SO FAR...WITH HIGHS IN THE MID 90S. THIS COMBINED
WITH DEW POINTS IN THE LOWER 70S WILL RESULT IN HEAT INDEX VALUES
OVER 100 FOR ROCHESTER AND IN THE NORTHERN GENESEE VALLEY AND
FINGER LAKES REGIONS. OTHERWISE...EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AND
EASTERN LAKE ONTARIO REGION TO DISSIPATE TOWARD THIS EVENING...AS
DAYTIME HEATING DIMINISHES AND AS WINDS INCREASE MIXING AND EXPAND
THE LAKE SHADOWING.
FOR TONIGHT AND INTO SATURDAY...THE FOCUS WILL SHIFT TO THE
POTENTIAL FOR SEVERE WEATHER...WITH LOCALLY HEAVY DOWNPOURS. THIS
WILL LIKELY COME IN TWO WAVES. THE FIRST CAN ALREADY BE SEEN
CLEARLY EARLY THIS AFTERNOON...ASSOCIATED WITH A LINE OF
THUNDERSTORMS DEVELOPING ACROSS CENTRAL MICHIGAN TO LAKE HURON.
THIS INITIAL WAVE WILL TRACK TOWARD OUR REGION THROUGH THE
AFTERNOON HOURS...BUT GIVEN THE STRONG SW FLOW ACROSS THE LAKES
EXPECT IT WILL WEAKEN RAPIDLY AS IT APPROACHES OUR REGION. HIGHER
RESOLUTION GUIDANCE IS IN GENERAL AGREEMENT WITH THE NAM/RGEM/HRRR
ALL SHOWING THIS GENERAL TREND. THERE IS STILL A POSSIBILITY THAT
THIS WILL HOLD TOGETHER LONG ENOUGH TO HAVE SOME IMPACT ON OUR
CWA...WITH THE SAINT LAWRENCE RIVER AND NORTH COUNTRY AND POSSIBLY
PORTIONS OF THE NIAGARA FRONTIER THE AREAS TO WATCH. IT WILL BE
TRICKY...SINCE THE LINE WILL PROBABLY BE QUITE IMPRESSIVE JUST
UPSTREAM OF THE LAKE BREEZE...WITH BOWING LINE SEGMENTS CAPABLE OF
PRODUCING STRONG WINDS. THIS INITIAL LINE WILL IMPACT OUR REGION
BETWEEN 700 PM AND 1000 PM.
BEHIND THIS...IS A SECONDARY LINE OF THUNDERSTORMS DEVELOPING
ALONG WHAT APPEARS TO BE A PRE-FRONTAL TROF WIND SHIFT BOUNDARY.
00/12Z RUNS OF THE NAM/RGEM AND RECENT RUNS OF THE HRRR CONTINUE
TO SUGGEST THAT THIS AREA WILL EXPAND...AND EVENTUALLY DROP ACROSS
OUR REGION DURING THE OVERNIGHT HOURS. THE LATER TIMING...AND
CLOSER PROXIMITY TO THE SHORTWAVE WILL MAKE THIS FEATURE MORE
LIKELY TO HOLD TOGETHER AS IT DROPS ACROSS THE LAKES AND ACROSS
WESTERN NEW YORK LATE TONIGHT AND INTO SATURDAY MORNING. THIS
TIMING IS CLIMATOLOGICALLY NOT FAVORABLE FOR SEVERE WEATHER...BUT
GIVEN THE SIGNIFICANT AMOUNT OF NIGHTTIME INSTABILITY...AND STILL
A FAIR AMOUNT OF SHEAR...IT WILL BEAR A RADAR WATCH IF IT DOES
INDEED DEVELOP AS FORECAST.
IN ADDITION TO THE SEVERE WEATHER THREAT...THERE WILL ALSO BE A
RISK FOR LOCALLY HEAVY DOWNPOURS. PRECIPITABLE WATER VALUES WILL
BE 1.75 TO 2.00 INCHES...AND WHILE STORMS WILL LIKELY BE
MOVING...LARGE AREAS OF CONVECTION OR BRIEF TRAINING COULD QUICKLY
ADD UP AND LEAD TO LOCALIZED FLOODING.
ON SATURDAY...EXPECT MOST OF THE SHOWERS AND THUNDERSTORM ACTIVITY
TO SLIDE TO THE SOUTH AND EAST OF THE AREA LATE MORNING AND INTO
THE AFTERNOON HOURS. THE ACTUAL FRONTAL BOUNDARY WILL NOT CROSS
UNTIL LATER IN THE DAY...BUT MUCH DRIER AIR WILL MOVE IN BEHIND
THE PRE-FRONTAL TROF WITH ONLY MARGINAL CHANCE FOR ANY SHOWERS OR
THUNDERSTORMS ALONG THE FRONT ITSELF WHICH WILL CROSS LATE IN THE
DAY SATURDAY. WITH COOLER AIR MOVING IN AND LINGERING
PRECIPITATION...TEMPERATURES WILL BE NOTABLY COOLER ON
SATURDAY...WITH HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
BY SATURDAY EVENING...MOST OF THE 12Z GUIDANCE PACKAGES ARE IN GOOD
AGREEMENT THAT THE COLD FRONTAL ZONE AND THE BULK OF ITS ASSOCIATED
PRECIPITATION WILL HAVE SLIPPED TO OUR SOUTH...SAVE FOR THE NAM
WHICH IS A SLOWER OUTLIER. AS THIS PARTICULAR MODEL HAS SHOWN SOME
RUN-TO-RUN INCONSISTENCIES WITH THE TIMING OF THE FRONT OVER THE
PAST DAY OR SO...WILL DISREGARD IT IN FAVOR OF THE FASTER GFS/
GEM/ECMWF CONSENSUS AND OUR EXISTING CONTINUITY...ALL OF WHICH
ADVERTISE A GENERALLY DRY NIGHT. IN THE WAKE OF THE FRONT...A HIGHLY
ANTICIPATED COOLER AND DRIER AIRMASS WILL SPREAD SOUTH ACROSS OUR
AREA THROUGH THE COURSE OF THE NIGHT...FINALLY BRINGING SOME MUCH
WELCOMED RELIEF FROM THE TROPICAL HEAT AND HUMIDITY LEVELS OF THE
PAST WEEK. EXPECT OVERNIGHT LOWS TO DROP TO THE MID 50S TO LOWER
60S...WHILE SURFACE DEWPOINTS FALL BACK TO MUCH MORE COMFORTABLE
LEVELS IN THE 50S.
WITH THE WATERS OF THE LOWER GREAT LAKES NOW IN THE MID TO UPPER 70S
/OR AROUND +25C/...AND THE INCOMING COOLER AIRMASS EVENTUALLY
FEATURING 850 MB TEMPS OF AROUND +10C BY LATER IN THE NIGHT...WE MAY
WELL SEE SOME LAKE EFFECT CLOUDINESS DEVELOP SOUTH OF THE LAKES
OVERNIGHT...THOUGH THE INCOMING AIRMASS WILL LIKELY REMAIN TOO DRY
AND FEATURE TOO LOW OF A SUBSIDENCE INVERSION TO SUPPORT ANY LAKE
EFFECT SHOWERS.
SUNDAY AND SUNDAY NIGHT...SURFACE HIGH PRESSURE WILL SETTLE DIRECTLY
ACROSS THE LOWER LAKES AND NEW YORK STATE IN THE WAKE OF THE COLD
FRONT. COUPLED WITH STRONG MIDSUMMER DIURNAL EFFECTS...THIS SHOULD
RESULT IN ANY LAKE EFFECT CLOUDS FROM SATURDAY NIGHT BREAKING UP
DURING THE COURSE OF SUNDAY MORNING...LEADING TO A DECENT AMOUNT OF
SUNSHINE EVERYWHERE FOR THE AFTERNOON. MEANWHILE...850 MB TEMPS
RANGING FROM +9C NORTH TO +13C SOUTH SHOULD SUPPORT RATHER PLEASANT
HIGHS IN THE MID TO UPPER 70S...WHILE DEWPOINTS CONTINUE TO LOWER TO
THE 50-55 DEGREE RANGE WITH DIURNAL MIXING. THE COOLER AND QUIET
WEATHER WILL THEN CONTINUE INTO SUNDAY NIGHT...WHEN LOWS SHOULD
RANGE THROUGH THE 50S IN MOST LOCATIONS...WITH SOME UPPER 40S EVEN
POSSIBLE ACROSS PORTIONS OF THE NORTH COUNTRY. WITH THE LOW LEVEL
FLOW VEERING MORE EASTERLY...DO NOT EXPECT LAKE EFFECT CLOUDINESS TO
BE A PROBLEM FOR SUNDAY NIGHT...THOUGH THERE WILL PROBABLY BE SOME
INCREASE IN MID/HIGH CLOUDS OVERNIGHT IN ADVANCE OF A MODEST
SHORTWAVE TROUGH THAT WILL BE WORKING INTO THE CENTRAL GREAT LAKES.
MONDAY AND MONDAY NIGHT...THE SURFACE HIGH WILL SLIDE EAST ACROSS
NEW ENGLAND AND OUT TO SEA...WHILE THE AFOREMENTIONED SHORTWAVE
TROUGH TO OUR WEST SETTLES ACROSS THE LOWER LAKES AND NY/PA...WHILE
ALSO SPAWNING SOME SEMBLANCE OF A WEAK SURFACE REFLECTION. WHILE THE
VARIOUS GUIDANCE PACKAGES STILL DIFFER WITH RESPECT TO HOW FAST
THIS SYSTEM ARRIVES AND EXACTLY HOW WELL DEVELOPED IT WILL BE...ALL
HAVE CONTINUED THE RECENT TREND TOWARD A FASTER AND SOMEWHAT MORE
DEVELOPED SYSTEM...WITH A PLUME OF DEEPER MOISTURE AND WEAK TO
MODEST ISENTROPIC LIFT EVENTUALLY ADVECTING INTO OUR AREA BETWEEN
MONDAY AFTERNOON AND MONDAY NIGHT. WITH THIS AND OUR EXISTING
CONTINUITY OF A TOTALLY DRY FORECAST BOTH IN MIND...HAVE ELECTED TO
GRADUALLY INTRODUCE SOME LOWER CHANCE POPS INTO AREAS SOUTH OF LAKE
ONTARIO MONDAY AFTERNOON...BEFORE BRINGING HIGHER CHANCE RANGE POPS
INTO THE ENTIRE AREA MONDAY NIGHT. THE HIGHEST PRECIPITATION CHANCES
WILL BE FOCUSED ACROSS OUR FINGER LAKES AND NORTH COUNTRY ZONES...
WHICH WILL BE CLOSEST TO THE BEST AREA OF DEEPER MOISTURE AND
ISENTROPIC LIFT. TEMPS THROUGH THIS LATTER PORTION OF THE PERIOD
WILL RETURN TO MIDSUMMER NORMS GIVEN THE WEAK WARM AIR ADVECTION
PATTERN...WITH DAYTIME HIGHS OF AROUND 80 EXPECTED ON MONDAY...
FOLLOWED BY LOWS IN THE LOWER TO MID 60S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
IN THE LONG TERM PORTION OF THE FORECAST...THE LARGE-SCALE WEATHER
PATTERN ACROSS NORTH AMERICA WILL REVERT TO ONE WE HAVE BEEN MORE
FAMILIAR WITH FOR THE BULK OF THE SPRING AND SUMMER...THAT OF A
BROAD RIDGE OVER THE ROCKIES AND WESTERN PLAINS...WITH A
CORRESPONDING BROAD DOWNSTREAM TROUGH DEVELOPING OVER THE GREAT
LAKES AND NORTHEAST. THIS CHANGE IN THE PATTERN WILL RESULT IN AN
EXTENDED PERIOD OF MORE NORMAL SUMMERTIME TEMPERATURES FOR OUR
REGION...WITH DAILY HIGHS AVERAGING WITHIN A FEW DEGREES OF 80 EACH
DAY...AND NIGHTTIME LOWS GENERALLY RANGING IN THE LOWER TO MID 60S.
WITH RESPECT TO PRECIPITATION CHANCES...THE FORECAST PICTURE REMAINS
CONSIDERABLY MORE MUDDLED. UNDER THE EXPECTED LARGE-SCALE FLOW
REGIME...NUMEROUS PIECES OF SHORTWAVE ENERGY SHOULD ROTATE THROUGH
THE DEVELOPING TROUGH AND LEAD TO PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS...HOWEVER THE MEDIUM RANGE GUIDANCE REMAINS ALL OVER
THE MAP WITH RESPECT TO THE TIMING AND STRENGTH OF THESE FEATURES.
WITH THIS IN MIND...HAVE JUST CONTINUED TO BROADBRUSH SOME LOW
CHANCE POPS ACROSS THE ENTIRE PERIOD FOR NOW...AND WILL WAIT UNTIL
BETTER MODEL AGREEMENT DEVELOPS BEFORE TRYING TO PROVIDE MORE
REFINED/DETAILED PRECIPITATION PROBABILITIES AND TIMING. ALL THIS
SAID...THIS PERIOD LOOKS TO BE FAR FROM A WASHOUT AT THIS TIME...
WITH ANY SHOTS OF SHOWERS/STORMS LIKELY TO ALTERNATE WITH FREQUENT
DRY PERIODS.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
FOR THE 18Z TAF CYCLE...GUSTY SW WINDS TO BE THE MAIN IMPACT FOR
THIS AFTERNOON...WITH BUF/IAG/ROC/ART ALL SEEING PREVAILING GUSTS
IN THE 30 TO 35 KT RANGE. WIDELY SCATTERED THUNDERSTORMS MAY
BRIEFLY IMPACT JHW.
AFTER THIS...A LINE OF THUNDERSTORMS WILL APPROACH FROM THE WEST
23Z. THIS AREA WILL PROBABLY WEAKEN AS IT MOVES INTO OUR
REGION...BUT MAY HOLD TOGETHER LONG ENOUGH TO IMPACT IAG/ART...AND
POSSIBLY BUF/ROC DURING THE EVENING HOURS. STEADIER THUNDERSTORMS
ARE LIKELY LATE TONIGHT AS A LARGER AREA IS FORECAST TO DROP
ACROSS THE REGION. ALL THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND
WIND SHIFTS...WITH HEAVY RAIN LOWERING VSBY TO 1SM.
STORMS WILL DROP FROM N-S LATE TONIGHT AND INTO SATURDAY
MORNING...WITH CONDITIONS IMPROVING TO VFR.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY MORNING...VFR.
MONDAY AFTERNOON THROUGH WEDNESDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030-042-043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
256 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THIS AFTERNOON HOT AND WINDY CONDITIONS WILL
PERSIST ACROSS THE REGION. AN UPPER LEVEL TROF SOUTH OF HUDSON BAY
WILL DIVE TOWARD THE UPPER LAKES THROUGH TONIGHT...PUSHING AN
ASSOCIATED COLD FRONTAL BOUNDARY TOWARD OUR REGION. WHILE THE
FRONT ITSELF WILL REMAIN WELL UPSTREAM...THIS WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. THE VAD WIND PROFILE ALREADY SHOWS
40 KNOT WINDS AT 925 MB...AND THESE ARE FORECAST TO INCREASE A BIT
MORE THROUGH SUNSET FROM WEST TO EAST. THESE SOUTHWEST WINDS
SHOULD FAIRLY READILY MIX TO THE SURFACE...WITH THE LAKE BREEZE
ENHANCING THIS FLOW TO THE NORTHEAST OF THE LAKES. THE WINDIEST
CONDITIONS SHOULD BE ACROSS THE NIAGARA FRONTIER AND IMMEDIATE LAKE
ERIE SHORELINE...WHICH INCLUDES THE BUFFALO METRO AREA. GUSTS
SHOULD GENERALLY RUN IN THE 40 TO 45 MPH RANGE IN THIS AREA...WITH
PEAK GUSTS LIKELY TO TOP OUT NEAR 50 MPH. EXPECT THAT WITH THE
FULL FOLIAGE...THIS WILL RESULT IN A FEW DOWNED TREE LIMBS...WITH
SOME SPOTTY POWER OUTAGES POSSIBLE. ELSEWHERE WILL BE BREEZY AS
WELL...BUT INTERIOR LOCATIONS WILL GENERALLY LESS WINDY.
THE OTHER BIG ISSUE WILL SIMPLY BE THE HOT WEATHER. THE SW FLOW
OFF THE LAKE SHOULD HOLD TEMPERATURES 90 IN THE BUFFALO
AREA...BUT ROCHESTER EASTWARD THIS FLOW WILL DOWNSLOPE AND ADD A
FEW MORE DEGREES TO THE ALREADY HOT WEATHER. FOR MANY THIS WILL BE
THE HOTTEST DAY SO FAR...WITH HIGHS IN THE MID 90S. THIS COMBINED
WITH DEW POINTS IN THE LOWER 70S WILL RESULT IN HEAT INDEX VALUES
OVER 100 FOR ROCHESTER AND IN THE NORTHERN GENESEE VALLEY AND
FINGER LAKES REGIONS. OTHERWISE...EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AND
EASTERN LAKE ONTARIO REGION TO DISSIPATE TOWARD THIS EVENING...AS
DAYTIME HEATING DIMINISHES AND AS WINDS INCREASE MIXING AND EXPAND
THE LAKE SHADOWING.
FOR TONIGHT AND INTO SATURDAY...THE FOCUS WILL SHIFT TO THE
POTENTIAL FOR SEVERE WEATHER...WITH LOCALLY HEAVY DOWNPOURS. THIS
WILL LIKELY COME IN TWO WAVES. THE FIRST CAN ALREADY BE SEEN
CLEARLY EARLY THIS AFTERNOON...ASSOCIATED WITH A LINE OF
THUNDERSTORMS DEVELOPING ACROSS CENTRAL MICHIGAN TO LAKE HURON.
THIS INITIAL WAVE WILL TRACK TOWARD OUR REGION THROUGH THE
AFTERNOON HOURS...BUT GIVEN THE STRONG SW FLOW ACROSS THE LAKES
EXPECT IT WILL WEAKEN RAPIDLY AS IT APPROACHES OUR REGION. HIGHER
RESOLUTION GUIDANCE IS IN GENERAL AGREEMENT WITH THE NAM/RGEM/HRRR
ALL SHOWING THIS GENERAL TREND. THERE IS STILL A POSSIBILITY THAT
THIS WILL HOLD TOGETHER LONG ENOUGH TO HAVE SOME IMPACT ON OUR
CWA...WITH THE SAINT LAWRENCE RIVER AND NORTH COUNTRY AND POSSIBLY
PORTIONS OF THE NIAGARA FRONTIER THE AREAS TO WATCH. IT WILL BE
TRICKY...SINCE THE LINE WILL PROBABLY BE QUITE IMPRESSIVE JUST
UPSTREAM OF THE LAKE BREEZE...WITH BOWING LINE SEGMENTS CAPABLE OF
PRODUCING STRONG WINDS. THIS INITIAL LINE WILL IMPACT OUR REGION
BETWEEN 700 PM AND 1000 PM.
BEHIND THIS...IS A SECONDARY LINE OF THUNDERSTORMS DEVELOPING
ALONG WHAT APPEARS TO BE A PRE-FRONTAL TROF WIND SHIFT BOUNDARY.
00/12Z RUNS OF THE NAM/RGEM AND RECENT RUNS OF THE HRRR CONTINUE
TO SUGGEST THAT THIS AREA WILL EXPAND...AND EVENTUALLY DROP ACROSS
OUR REGION DURING THE OVERNIGHT HOURS. THE LATER TIMING...AND
CLOSER PROXIMITY TO THE SHORTWAVE WILL MAKE THIS FEATURE MORE
LIKELY TO HOLD TOGETHER AS IT DROPS ACROSS THE LAKES AND ACROSS
WESTERN NEW YORK LATE TONIGHT AND INTO SATURDAY MORNING. THIS
TIMING IS CLIMATOLOGICALLY NOT FAVORABLE FOR SEVERE WEATHER...BUT
GIVEN THE SIGNIFICANT AMOUNT OF NIGHTTIME INSTABILITY...AND STILL
A FAIR AMOUNT OF SHEAR...IT WILL BEAR A RADAR WATCH IF IT DOES
INDEED DEVELOP AS FORECAST.
IN ADDITION TO THE SEVERE WEATHER THREAT...THERE WILL ALSO BE A
RISK FOR LOCALLY HEAVY DOWNPOURS. PRECIPITABLE WATER VALUES WILL
BE 1.75 TO 2.00 INCHES...AND WHILE STORMS WILL LIKELY BE
MOVING...LARGE AREAS OF CONVECTION OR BRIEF TRAINING COULD QUICKLY
ADD UP AND LEAD TO LOCALIZED FLOODING.
ON SATURDAY...EXPECT MOST OF THE SHOWERS AND THUNDERSTORM ACTIVITY
TO SLIDE TO THE SOUTH AND EAST OF THE AREA LATE MORNING AND INTO
THE AFTERNOON HOURS. THE ACTUAL FRONTAL BOUNDARY WILL NOT CROSS
UNTIL LATER IN THE DAY...BUT MUCH DRIER AIR WILL MOVE IN BEHIND
THE PRE-FRONTAL TROF WITH ONLY MARGINAL CHANCE FOR ANY SHOWERS OR
THUNDERSTORMS ALONG THE FRONT ITSELF WHICH WILL CROSS LATE IN THE
DAY SATURDAY. WITH COOLER AIR MOVING IN AND LINGERING
PRECIPITATION...TEMPERATURES WILL BE NOTABLY COOLER ON
SATURDAY...WITH HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
THE MAIN STORY THIS WEEKEND WILL BE THE PASSAGE OF A COLD FRONT THAT
WILL BREAK THE HEAT WAVE THE REGION HAS BEEN EXPERIENCING OF LATE
AND USHER IN A RETURN TO MUCH MORE SEASONABLE TEMPERATURES. AS WE
OPEN THE WEEKEND SATURDAY MORNING HOWEVER...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL STILL
LIKELY BE CROSSING THE FORECAST AREA. THIS INITIAL BATCH OF
CONVECTIVE ACTIVITY SHOULD TAPER OFF FROM NORTHWEST TO SOUTHEAST
DURING THE MORNING HOURS WITH THE PASSAGE OF THE TROUGH...HOWEVER A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
DURING THE AFTERNOON/EARLY EVENING HOURS ACCOMPANYING THE PASSAGE OF
THE ACTUAL COLD FRONT. WITH THE LOW LEVEL JET WELL TO OUR EAST AND
MODEL CAPES ONLY IN THE 500-1000 J/KG RANGE...ANY SHOWERS AND
THUNDERSTORMS THAT DO OCCUR SHOULD REMAIN RELATIVELY BENIGN. THE
COMBINATION OF CLOUD COVER AND THE GRADUAL FILTERING OF COOLER AIR
INTO THE REGION BEHIND THE PRE-FRONTAL TROUGH MEANS THAT MOST AREAS
SHOULD ONLY TOP OUT IN THE LOWER 80S...THOUGH AREAS SOUTHEAST OF
LAKE ONTARIO COULD STILL SEE HIGHS IN THE MID 80S THANKS TO
DOWNSLOPING SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN/NORTH CENTRAL NEW YORK SATURDAY
EVENING BRINGING AN END TO ANY LINGERING PRECIPITATION AS MUCH
COOLER AND DRIER AIR ADVECTS INTO THE REGION. WITH THE MUCH
ANTICIPATED ARRIVAL OF THIS AIRMASS LOOK FOR TEMPERATURES TO DIP
INTO THE MID 50S ACROSS THE NORTH COUNTRY AND SOUTHERN TIER WHILE
THE LAKE PLAINS AND FINGER LAKES WILL COOL INTO THE LOWER 60S. THE
COOLING TEMPERATURES COMBINED WITH ANY LINGERING MOISTURE FROM
FRIDAY NIGHT/SATURDAY/S RAINFALL COULD LEAD TO PATCHY FOG ACROSS THE
SOUTHERN TIER.
DRY AND MILD WEATHER WILL PREVAIL ON SUNDAY AND SUNDAY NIGHT AS HIGH
PRESSURE SETTLES OVER THE GREAT LAKES IN THE WAKE OF THE COLD FRONT.
HIGHS IN THE MID TO UPPER 70S ON SUNDAY WILL PROVIDE A REFRESHING
BREAK FROM THE RECENT HEAT. WHILE MOST AREAS SHOULD SEE PLENTY OF
SUNSHINE...WITH 850MB TEMPERATURES COOLING TO THE +8 TO +10C RANGE
AND LAKE TEMPERATURES RUNNING A TOASTY +25C...CANNOT RULE OUT THE
POSSIBILITY OF SOME LAKE INDUCED CLOUD COVER CREEPING INTO WESTERN
NEW YORK. ANY LAKE INDUCED CLOUD COVER SHOULD DIMINISH SUNDAY
EVENING AS WINDS VEER TO TO THE EAST...HOWEVER EXPECT MID/HIGH
CLOUDS TO MOVE IN FROM THE WEST LATER SUNDAY NIGHT AHEAD OF A WEAK
SHORTWAVE CROSSING THE CENTRAL GREAT LAKES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
BY MONDAY HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST...
ALLOWING SOUTHERLY RETURN FLOW TO BEGIN. MODELS CONTINUE TO BE A
LITTLE MORE AGGRESSIVE IN BRINGING A PLUME OF DEEPER MOISTURE AND
PERHAPS A FEW SHOWERS INTO EASTERN PA AND NY...BUT IT STILL APPEARS
THIS WILL REMAIN MAINLY TO OUR EAST. HAVE CONTINUED WITH A DRY
FORECAST FOR MONDAY WITH TEMPERATURES MODERATING TO VERY CLOSE TO
AVERAGE.
TUESDAY THROUGH THURSDAY A BROAD TROUGH WILL SLOWLY EVOLVE IN THE
GREAT LAKES. NUMEROUS SHORTWAVE FEATURES WILL ROTATE THROUGH THE
DEVELOPING TROUGH...BUT MODEL GUIDANCE REMAINS OUT OF PHASE WITH
RESPECT TO TIMING AND AMPLITUDE OF THESE FEATURES. AT THIS POINT
HAVE JUST BLANKETED THE PERIOD WITH LOW CHANCE POPS UNTIL BETTER
MODEL AGREEMENT ALLOWS FOR MORE REFINED TIMING. TEMPERATURES WILL
RETURN TO A LITTLE ABOVE AVERAGE AND HUMIDITY WILL INCREASE...BUT
BOTH WILL REMAIN BELOW THE LEVELS OF THIS WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
FOR THE 18Z TAF CYCLE...GUSTY SW WINDS TO BE THE MAIN IMPACT FOR
THIS AFTERNOON...WITH BUF/IAG/ROC/ART ALL SEEING PREVAILING GUSTS
IN THE 30 TO 35 KT RANGE. WIDELY SCATTERED THUNDERSTORMS MAY
BRIEFLY IMPACT JHW.
AFTER THIS...A LINE OF THUNDERSTORMS WILL APPROACH FROM THE WEST
23Z. THIS AREA WILL PROBABLY WEAKEN AS IT MOVES INTO OUR
REGION...BUT MAY HOLD TOGETHER LONG ENOUGH TO IMPACT IAG/ART...AND
POSSIBLY BUF/ROC DURING THE EVENING HOURS. STEADIER THUNDERSTORMS
ARE LIKELY LATE TONIGHT AS A LARGER AREA IS FORECAST TO DROP
ACROSS THE REGION. ALL THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND
WIND SHIFTS...WITH HEAVY RAIN LOWERING VSBY TO 1SM.
STORMS WILL DROP FROM N-S LATE TONIGHT AND INTO SATURDAY
MORNING...WITH CONDITIONS IMPROVING TO VFR.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY MORNING...VFR.
MONDAY AFTERNOON THROUGH WEDNESDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030-042-043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL
SHORT TERM...WOOD
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EDT FRI JUL 19 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE CAROLINAS ON SUNDAY AND THEN STALL
ACROSS THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM FRIDAY...
12Z SOUNDINGS FROM AROUND THE AREA SHOWED A MODEST CAP AROUND 700MB
AT KMHX...WITH THE CAP AT THAT LEVEL MUCH WEAKER TOWARD KGSO GIVEN
TEMPERATURES 2C TO 3C COOLER. THE LATEST RUC INDICATES GENERAL
SUBSIDENCE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...WITH WEAK
WINDS ALOFT AND THE MOST FAVORABLE ITEMS FOR ANY RELATIVELY DEEP
LIFT BEING THE SURFACE TROUGH LINGERING OVER THE WESTERN PIEDMONT...
COUPLED WITH A WEAK 850MB TROUGH IN THE SAME AREA AND AVAILABLE
LOW-LEVEL MOISTURE. OVERALL MOISTURE SHOULD BE BEST TOWARD THE
NORTHWEST PIEDMONT LATER THIS AFTERNOON WHERE HIGHER 850MB THETA-E
VALUES ARE FORECAST. IT IS ALSO IN THAT LOCATION WHERE THE BETTER
1000-500MB LAPSE RATES ARE FORECAST...NEAR 6.75C/KM...AND WHERE THE
BETTER INSTABILITY LIES...2000-2500J/KG VERSUS A FORECAST OF ONLY
1000-1500J/KG TOWARD THE COASTAL PLAIN. CONVECTION-ALLOWING
MODELS...GIVEN THE GENERAL SUBSIDENCE...ARE MOSTLY RELUCTANT TO
FORECAST MUCH PRECIPITATION IN CENTRAL NORTH CAROLINA...BUT WITHIN
THE SLIGHT CHANCE RANGE...THE BETTER CHANCE SHOULD MAINLY BE ALONG
AND NORTH/WEST OF INTERSTATE 85. AS NOTED PREVIOUSLY...WEAK WINDS
ALOFT WILL ALLOW ANY OF THE ISOLATED STORMS TO MOVE ONLY VERY
SLOWLY. 1000-850MB THICKNESSES AT 12Z AND FORECAST LATE THIS
AFTERNOON ARE BASICALLY PERSISTENCE FROM THURSDAY...AND HAVE
FORECAST HIGHS CLOSE TO THOSE OF THURSDAY AS A RESULT. THIS PLACES
MOST LOCATIONS WITH HEAT INDICES AROUND 100...A COUPLE OF DEGREES
WARMER TOWARD KIXA AND KRZZ. ANY THUNDERSTORMS SHOULD DIMINISH
DIURNALLY...WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 245 AM FRIDAY...
THE NORTHERN STREAM TROUGH AND ASSOCIATED SFC COLD FRONT WILL REMAIN
NORTH OF THE AREA...SAGGING SOUTH INTO THE SOUTHERN OHIO VALLEY AND
NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING. NOT MANY DIFFERENCES
BETWEEN TODAY AND SATURDAY WITH THE SAME MESOSCALE FORCING DRIVING
ISOLATED TO SCATTERED DIURNAL CONVECTION SATURDAY AFTERNOON
HIGHS IN THE LOWER 90S. LOWS IN THE LOWER TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 150 PM FRIDAY...
SUNDAY AND MONDAY...
THE BACKDOOR COLD FRONT OVER THE OHIO VALLEY WILL BE SLOW TO EDGE
SOUTH AND IS EXPECTED TO STALL NORTH OF THE AREA SUNDAY AND MONDAY
AS IT ALIGNS PARALLEL TO THE FLOW ALONG THE LOW AMPLITUDE UPPER
TROF. TANGIBLE DISTURBANCES IN THE LARGER FLOW REGIME ARE NOT
READILY EVIDENT AT THIS TIME...BUT MOISTURE AND INSTABILITY WILL BE
MORE THAN ADEQUATE FOR SUPPORT OF MAINLY DIURNAL CONVECTION. WILL
CONTINUE POPS IN THE 50-60 PERCENT RANGE BOTH DAYS. SMALL HEIGHT
FALLS AND REDUCED INSOLATION WILL TAKE THE EDGE OFF OUR HIGH
TEMPERATURES...AND HIGHS BOTH DAYS WILL BE SLIGHTLY COOLER THAN
NORMAL...IN THE 85 TO 90 RANGE.
TUESDAY THROUGH FRIDAY...
VERY SLOW EASTWARD TRANSLATION AND DEEPENING OF THE UPPER TROF TO
OUR WEST WILL KEEP US IN AN UNSETTLED PATTERN THROUGH AT LEAST
THURSDAY. THE STALLED FRONT NORTH OF THE AREA BECOMES MORE DIFFUSE
WITH TIME... MEANWHILE THE PERSISTENT LEE TROF ALONG THE EASTERN
SEABOARD SHARPENS IN STRENGTHENING SOUTHWEST FLOW AHEAD OF THE
DEEPENING UPPER TROF. THE PROBABILITY OF PRECIP WILL REMAIN ABOVE
NORMAL ACROSS THE AREA AS THE NEAR STAGNANT AIRMASS WILL REQUIRE
LITTLE FORCING TO GENERATE CONVECTION...ITS THE DISTRIBUTION AND
TIMING WHICH WILL REMAIN LOW CONFIDENCE. THAT SAID...WILL HAVE 40-50
POPS TUE THROUGH FRI...AGAIN FOCUSING ON MAX DIURNAL HEATING...WITH
PERSISTENCE HIGHS FROM 85-90. THE UPPER TROF MAY MAKE ITS MOVE EAST
ACROSS THE AREA LATE THIS WEEK...WHICH WOULD ENHANCE AS WELL AS
PROVIDE ORGANIZATION FOR CONVECTION IN THE LATE THURSDAY OR FRIDAY
TIME FRAME...AS WELL AS INITIATE A DRYING TREND FOR THE UPCOMING
WEEKEND...WE SHALL SEE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1205 PM FRIDAY...
VFR CONDITIONS ARE CURRENTLY BEING REPORTED ACROSS MOST OF CENTRAL
NC. THIS IS EXPECTED TO REMAIN THE CASE THROUGH THE 24 HOUR TAF
PERIOD...WITH THE EXCEPTION OF A FEW ISOLD TSTMS DURING THE REST OF
THIS AFTERNOON AND EARLY EVENING THAT MAY BRIEFLY REDUCE FLT
CONDITIONS TO MVFR.
BEYOND THE 24 HOUR TAF PERIOD:
OUTSIDE OF SOME EARLY MORNING FOG/STRATUS SATURDAY...VFR CONDITIONS
SHOULD PREVAIL WITH ONLY ISOLATED AFTERNOON STORMS. A SLOW MOVING
COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST ON SUNDAY AND
WILL STALL ACROSS THE AREA THROUGH EARLY NEXT WEEK. THIS WILL RESULT
IN NUMEROUS SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS...WITH SUB VFR CONDITIONS IN HEAVY RAIN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...MLM
AVIATION...NP/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1205 PM EDT FRI JUL 19 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE CAROLINAS ON SUNDAY AND THEN STALL
ACROSS THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM FRIDAY...
12Z SOUNDINGS FROM AROUND THE AREA SHOWED A MODEST CAP AROUND 700MB
AT KMHX...WITH THE CAP AT THAT LEVEL MUCH WEAKER TOWARD KGSO GIVEN
TEMPERATURES 2C TO 3C COOLER. THE LATEST RUC INDICATES GENERAL
SUBSIDENCE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...WITH WEAK
WINDS ALOFT AND THE MOST FAVORABLE ITEMS FOR ANY RELATIVELY DEEP
LIFT BEING THE SURFACE TROUGH LINGERING OVER THE WESTERN PIEDMONT...
COUPLED WITH A WEAK 850MB TROUGH IN THE SAME AREA AND AVAILABLE
LOW-LEVEL MOISTURE. OVERALL MOISTURE SHOULD BE BEST TOWARD THE
NORTHWEST PIEDMONT LATER THIS AFTERNOON WHERE HIGHER 850MB THETA-E
VALUES ARE FORECAST. IT IS ALSO IN THAT LOCATION WHERE THE BETTER
1000-500MB LAPSE RATES ARE FORECAST...NEAR 6.75C/KM...AND WHERE THE
BETTER INSTABILITY LIES...2000-2500J/KG VERSUS A FORECAST OF ONLY
1000-1500J/KG TOWARD THE COASTAL PLAIN. CONVECTION-ALLOWING
MODELS...GIVEN THE GENERAL SUBSIDENCE...ARE MOSTLY RELUCTANT TO
FORECAST MUCH PRECIPITATION IN CENTRAL NORTH CAROLINA...BUT WITHIN
THE SLIGHT CHANCE RANGE...THE BETTER CHANCE SHOULD MAINLY BE ALONG
AND NORTH/WEST OF INTERSTATE 85. AS NOTED PREVIOUSLY...WEAK WINDS
ALOFT WILL ALLOW ANY OF THE ISOLATED STORMS TO MOVE ONLY VERY
SLOWLY. 1000-850MB THICKNESSES AT 12Z AND FORECAST LATE THIS
AFTERNOON ARE BASICALLY PERSISTENCE FROM THURSDAY...AND HAVE
FORECAST HIGHS CLOSE TO THOSE OF THURSDAY AS A RESULT. THIS PLACES
MOST LOCATIONS WITH HEAT INDICES AROUND 100...A COUPLE OF DEGREES
WARMER TOWARD KIXA AND KRZZ. ANY THUNDERSTORMS SHOULD DIMINISH
DIURNALLY...WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 245 AM FRIDAY...
THE NORTHERN STREAM TROUGH AND ASSOCIATED SFC COLD FRONT WILL REMAIN
NORTH OF THE AREA...SAGGING SOUTH INTO THE SOUTHERN OHIO VALLEY AND
NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING. NOT MANY DIFFERENCES
BETWEEN TODAY AND SATURDAY WITH THE SAME MESOSCALE FORCING DRIVING
ISOLATED TO SCATTERED DIURNAL CONVECTION SATURDAY AFTERNOON
HIGHS IN THE LOWER 90S. LOWS IN THE LOWER TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
SUNDAY THROUGH THURSDAY:
THIS PERIOD WILL BE DOMINATED BY A SURFACE TROUGH/FRONTAL BOUNDARY
STALLING OVER THE MID ATLANTIC...WITH THE UPPER LEVEL TROUGH DIGGING
SOUTH INTO CENTRAL NC. GOOD MOISTURE ADVECTION FROM THE GULF IN
SOUTHWEST FLOW ALONG THE TROUGH AXIS WILL MOISTEN THE COLUMN...WITH
PW`S AROUND TWO INCHES FORECAST THROUGH TUESDAY NIGHT. DISTURBANCES
TRACKING OVER THE AREA ALONG THE BASE OF THE MID/UPPER TROUGH WILL
BE SUFFICIENT TO INITIATE CONVECTION...ESPECIALLY DURING THE
AFT/EVE...GIVEN THE MOIST AND UNSTABLE AIRMASS IN PLACE. CONFIDENCE
ON EXACTLY WHERE THE BEST CHANCES/COVERAGE OF SHOWERS AND STORMS
WILL OCCUR IS STILL LOW GIVEN THE UNCERTAINTY OF WHERE THE FRONT
WILL STALL. FOR NOW WILL CONTINUE TO CARRY AT LEAST A CHANCE OF
SHOWERS AND STORMS THROUGH THE PERIOD...WITH HIGHEST CHANCES DURING
THE AFT/EVE. WITH THE CURRENT CHANCES OF CONVECTION AND GIVEN THE
INCREASE IN MOISTURE EXPECTED...CLOUDY CONDITIONS WILL BE LIKELY
OVER CENTRAL NC DURING THIS TIME. TAKING CLOUDS AND PRECIP INTO
ACCOUNT...HIGH TEMPS IN THE MID 80S TO NEAR 90 DEGREES AND OVERNIGHT
LOWS IN THE UPPER 60S TO LOW 70S ARE EXPECTED THROUGH THE PERIOD.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1205 PM FRIDAY...
VFR CONDITIONS ARE CURRENTLY BEING REPORTED ACROSS MOST OF CENTRAL
NC. THIS IS EXPECTED TO REMAIN THE CASE THROUGH THE 24 HOUR TAF
PERIOD...WITH THE EXCEPTION OF A FEW ISOLD TSTMS DURING THE REST OF
THIS AFTERNOON AND EARLY EVENING THAT MAY BRIEFLY REDUCE FLT
CONDITIONS TO MVFR.
BEYOND THE 24 HOUR TAF PERIOD:
OUTSIDE OF SOME EARLY MORNING FOG/STRATUS SATURDAY...VFR CONDITIONS
SHOULD PREVAIL WITH ONLY ISOLATED AFTERNOON STORMS. A SLOW MOVING
COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST ON SUNDAY AND
WILL STALL ACROSS THE AREA THROUGH EARLY NEXT WEEK. THIS WILL RESULT
IN NUMEROUS SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS...WITH SUB VFR CONDITIONS IN HEAVY RAIN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...NP/CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1150 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1138 AM CDT FRI JUL 19 2013
LATE THIS MORNING...THE VISIBLE SATELLITE LOOP SHOWS A CLUSTER OF
SHOWERS NEAR REGINA SASKATCHEWAN...MOVING SOUTHEAST. OTHERWISE
JUST A FEW CLOUDS WERE ALONG THE NORTH DAKOTA - CANADIAN BORDER.
CURRENT THINKING STILL ASSUMES THE SHOWERS ASSOCIATED WITH A COLD
FRONTAL BOUNDARY MOVING THROUGH SOUTHERN CANADA WILL TRACK
INTO/DEVELOP ACROSS THE NORTHWEST LATE THIS AFTERNOON. OTHERWISE
MOSTLY SUNNY SKIES AND COOLER AND DRIER WEATHER FORECAST THROUGH
TODAY. CURRENT FORECAST LOOKING GOOD.
UPDATE ISSUED AT 932 AM CDT FRI JUL 19 2013
FRIDAY MORNING...THE CURRENT WEATHER CONDITIONS WERE DEFINED BY A
POST FRONTAL ENVIRONMENT WITH MOSTLY CLEAR SKIES AND LIGHT
NORTHWEST WINDS. THIS UPDATE WILL BE MAINLY TO PROVIDE CURRENT
TEMPERATURES AND RELATIVE HUMIDITY. THIS AFTERNOON...ANOTHER
FRONTAL SYSTEM WILL APPROACH FROM THE NORTHWEST AND BRING A SLIGHT
CHANCE FOR THUNDERSTORMS. CURRENT FORECAST LOOKS GOOD IN THIS
REGARD.
UPDATE ISSUED AT 627 AM CDT FRI JUL 19 2013
NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. CLEAR SKIES ACROSS
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING SO LOWERED
CLOUD COVER THIS MORNING ACROSS THE NORTH. DO EXPECT INCREASING
CLOUDS NORTH BY MID MORNING WITH SHOWER AND THUNDERSTORM CHANCES
HOLDING OFF UNTIL AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1138 AM CDT FRI JUL 19 2013
AT 11 AM CDT...SKIES WERE MOSTLY CLEAR. VFR CONDITIONS ARE
OBSERVED AND ARE FORECAST THROUGH THE 18Z TAF PERIOD. A WEAK COLD
FRONTAL BOUNDARY ACROSS SOUTHERN CANADA WILL BE THE FOCUS FOR
ISOLATED THUNDERSTORMS ACROSS NORTHERN NORTH DAKOTA AFTER
22Z...AND ACROSS THE SOUTH AFTER 00Z. THUNDERSTORMS SHOULD BE TOO
ISOLATED TO ACCURATELY FORECAST...SO PLAN TO CONTINUE TO EXPRESS
THE THUNDERSTORM HAZARD VIA VCTY (VICINITY).
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
143 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID AIR MASS OVER THE REGION WILL BREAK DOWN TONIGHT AS A
COLD FRONT MOVES INTO THE REGION. STORMS WILL ACCOMPANY THE FRONT
AS IT MOVES THROUGH THE AREA ON SATURDAY. COOLER AND DRIER WEATHER
ON TAP FOR SUNDAY...BUT THE HUMIDITY WILL RETURN EARLY NEXT WEEK.
TEMPERATURES WILL BE MORE COMFORTABLE WITH HIGHS AT OR SLIGHTLY
BELOW NORMAL THROUGH MOST OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...MADE MINOR ADJUSTMENTS FOR THE NEXT SEVERAL DAYS. FOR
TODAY ADDED A SLIGHT CHANCE TO THE NORTHWEST COUNTIES WHERE LIKE
THE PAST FEW DAYS THE HRRR SHOWED AFTERNOON DEVELOPMENT.
TEMPERATURES OVERNIGHT REMAINED HIGH IN THE MID 70S...WHICH WILL
PROVIDE A WARM START FOR HEAT ADVISORY CONDITIONS LATER TODAY.
LOOK FOR SCATTERED CLOUDS DEVELOPING THIS AFTERNOON...BUT NOT
ENOUGH COVERAGE TO KEEP TEMPERATURES FROM RETURNING TO THE
LOWER 90S...AND IN SOME W SITES IN THE MID 90S. EXPECT SOME LOW
LEVEL WIND SHEAR TO STRENGTHEN TODAY WITH STRONGER SOUTHWEST WINDS
ALOFT. MIXING MAY CAUSE A DROP OF DEWPOINTS SLIGHTLY...BUT THE
MOISTURE BEING ADVECTED IN COULD COUNTER THIS AND EASILY SUPPORT
HEAT INDEX VALUES AROUND 100-104F THIS AFTERNOON. SOME WEAK
CONVERGENCE COULD BE ENOUGH TO TRIGGER SOME ISOLATED STORMS MAINLY
ACROSS OUR SOUTHERN TIER OF COUNTIES UP INTO NW PA. THE LAKESHORE
COUNTIES SHOULD REMAIN RAIN FREE FOR THE BETTER PART OF THE DAY.
THE CONVECTION IS EXPECTED TO GET GOING MID DAY NORTH IN MI AND CANADA
WHERE THE DYNAMICS WILL BE THE BEST. MODELS ARE INDICATING SOME
SUBSIDENCE OVER MOST OF OUR AREA THIS AFTERNOON WHICH COULD LEAVE
US WITH MOSTLY SUNNY SKIES EXCEPT THE MORE SOUTHERN COUNTIES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
ALL EYES WILL BE ON THE CONVECTION ANTICIPATED TO OUR NORTH AND
ANY OUTFLOWS THAT COULD SINK ACROSS THE LAKE AND TRIGGER STORMS
THIS EVENING IN OUR NORTHERN COUNTIES. EXCLUDING THAT
SCENARIO...THE BEST CHANCE FOR THUNDERSTORMS WON`T BE UNTIL 03-06Z
AS THE FRONT SINKS SOUTH INTO OUR AREA. THE BOTTLED UP ENERGY IN
PLACE OVER THE REGION WITH CAPES EXCEEDING 3K J/KG WILL BE REDUCED
MARGINALLY OVERNIGHT...BUT NOT ENOUGH TO RULE OUT STRONG TO SEVERE
STORMS. WITH UNIDIRECTIONAL WIND SHEAR...WITH A DECENT AMOUNT OF
SPEED SHEAR...THE HIGHEST THREAT WILL BE STRONG STRAIGHT LINE
WINDS. THE SLOW MOVING FRONT WILL PUSH INTO THE AREA DURING THE
EARLY MORNING HOURS ON SATURDAY. THIS WILL PROVIDE A FOCUS FOR
MORE CONVECTION ON SATURDAY...GRADUALLY CLEARING FROM NW TO SE
DURING THE AFTERNOON. SPC HAS THE REGION OUTLOOKED FOR SLIGHT RISK
OF SEVERE WEATHER FOR SATURDAY. THE STORM MOTIONS WILL BE
SUFFICIENT TO KEEP THE FLOOD RISK LIMITED TO ONLY AREAS WHERE
THERE MAY BE TRAINING. CONCERN HERE WILL BE WHERE THE FRONT OR
OTHER BOUNDARIES HANG UP...OTHERWISE THE HIGHEST QPF LOOKS TO BE
OVER NW PA. OVERALL LOOKING AT A 0.5" WIDESPREAD AVERAGE WITH
LOCALLY HIGHER AMOUNTS.
BEHIND FROPA A COOLER AND DRIER HIGH OUT OF CANADA WILL SLIDE IN
FOR SUNDAY GIVING A NICE BREAK TO THE HOT HUMID WEATHER OF THE
LAST WEEK. BY MONDAY AN UPPER LVL TROF WILL DEVELOP OVER THE OH
VALLEY AND WE`LL SEE A RETURN OF MUGGY CONDITIONS. TEMPERATURES
HOWEVER WILL REMAIN AT OR BELOW SEASONAL NORMALS AS THE
THICKNESSES DROP. THE PRESENCE OF THE TROUGH AND INCREASED
MOISTURE RETURN WILL UNFORTUNATELY PUT US BACK INTO A WETTER
PATTERN...THOUGH NOTHING ORGANIZED AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STILL PLENTY OF UNCERTAINTY IN THE FORECAST FOR TUESDAY THROUGH
THURSDAY AS PIECES OF JET ENERGY MOVE THROUGH A TROUGH THAT WILL BE
OVER THE GREAT LAKES REGION. FOR NOW HAVE SLIGHT CHANCE TO CHANCE
POPS IN THE FORECAST FOR MOST OF THE REGION.
TEMPERATURES TUESDAY THROUGH THURSDAY SHOULD BE VERY CLOSE TO
SEASONAL AVERAGES.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
POP UP THUNDERSTORMS WILL SPREAD ACROSS MUCH OF NE OH/NW PA THIS
AFTERNOON...INLAND FROM THE LAKE ERIE LAKE BREEZE. THE ODDS OF A
DIRECT HIT ON AN AVIATION TERMINAL ARE PROBABLY 30-40 PERCENT AND
WILL FORECAST "VICINITY" IN THE TAF THIS AFTERNOON EXCEPT AT KTOL
AND KERI WHERE THEY SHOULD BE PROTECTED BY THE PROXIMITY TO LAKE
ERIE.
A LINE OF SHOWERS AND THUNDERSTORMS WILL SLIDE ACROSS LAKE
ERIE TONIGHT AHEAD OF THE COLD FRONT. THE STORMS MAY BE WEAKENING
BY THE EARLY MORNING HOURS BUT THERE IS A GOOD CHANCE OF MVFR
CONDITIONS AND A CHANCE FOR IFR VISIBILITIES IN THE HEAVIER
THUNDERSTORMS.
MVFR STRATOCUMULUS CEILINGS WILL LIKELY DEVELOP AFTER THE
SHOWERS/STORMS EARLY SATURDAY OR FIRST THING SATURDAY MORNING.
CEILINGS WILL LIFT TO VFR SATURDAY AFTERNOON. NEW SHOWERS/STORMS
MAY DEVELOP SATURDAY AFTERNOON FROM NEAR KYNG TO KCAK AND KMFD BUT
NOT A LOT OF CONFIDENCE AND WILL LEAVE THEM OUT OF THE FORECAST
FOR NOW.
GUSTY WINDS THIS AFTERNOON WILL SETTLE TONIGHT AND SHIFT
TO THE WEST SATURDAY MORNING AS THE COLD FRONT BEGINS TO SLIDE
ACROSS THE AREA.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG. SHOWERS AND
THUNDERSTORMS MAY ALSO CAUSE NON VFR CONDITIONS MONDAY THRU
WEDNESDAY.
&&
.MARINE...
A COLD FRONT WILL MOVE INTO THE UPPER GREAT LAKES TODAY AS HIGH
PRESSURE MOVES TO THE SOUTHEASTERN US. THIS WILL ALLOW A STRONGER
PRESSURE GRADIENT TO DEVELOP OVER THE LAKE TODAY. SOUTHWEST WINDS OF
10 TO 20 KNOTS SHOULD BE ENOUGH TO BUILD WAVES TO 3 TO 5 FEET FROM
WILLOWICK TO RIPLEY. THE LARGEST WAVES WILL LIKELY BE IN THE PA
WATERS. SO WITH THAT SAID WE WILL HOIST A SMALL CRAFT ADVISORY THAT
WILL REMAIN IN EFFECT THROUGH TONIGHT.
THE COLD FRONT WILL MOVE SOUTHEAST ACROSS LAKE ERIE ON SATURDAY.
HIGH PRESSURE WILL THEN BUILD ACROSS THE GREAT LAKES ON SUNDAY
BEFORE SHIFTING EAST AND STAYING NORTH OF LAKE ERIE ON MONDAY.
NORTHEAST WINDS WILL DEVELOP BY SUNDAY MORNING WITH CHOPPY
CONDITIONS POSSIBLE FOR THE WESTERN HALF OF THE LAKE. WINDS SHOULD
BECOME SOUTHERLY BY MONDAY AS WARM FRONT LIFTS ACROSS THE LAKE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ003-006>011-
013-017>023-027>033-036>038-047.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON/TK
SHORT TERM...JAMISON
LONG TERM...MULLEN
AVIATION...KOSARIK
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
152 PM EDT FRI JUL 19 2013
.SYNOPSIS...
THE SUBTROPICAL RIDGE OVER THE EASTERN UNITED STATES WILL WEAKEN
AND SHIFT EASTWARD...YIELDING TO A VIGOROUS NORTHERN STREAM
SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES INTO THE NEW
ENGLAND. IT WILL BE UNSEASONABLY WARM UNTIL THE ASSOCIATED COLD
FRONTAL PASSAGE LATER SATURDAY. THE COLD FRONT COULD TRIGGER SOME
SEVERE THUNDERSTORMS. A BROAD UPPER LEVEL TROUGH SHOULD BUILD
OVER THE REGION FROM SUNDAY INTO NEXT WEEK. THIS PATTERN WILL
FEATURE A RETURN TO NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
17Z...TSTMS ARE DEVELOPING IN AREAS WHERE THE MESO MDLS HAD
PROJECTED - ON THE ELEVATED TERRAIN FROM NRN WV INTO SW PA AND
DOWNWIND OF LAKE ERIE. A FEW ISOLD CELLS ALSO FIRED OVER THE SE
PIEDMONT FROM NEAR MDT-LNS TO JUST NORTH OF RDG. STORM NEAR LNS
GREW QUICKLY TAPPING ABUNDANT CAPE (90/75 AT 16Z) WITH TOPS OVER
40KFT. THE LATEST RAPID-REFRESH HRRR SUGGEST A LINE OF STORMS MAY
DOWNWIND OF LAKE ERIE FROM NRN OH ACRS NW PA LATE THIS AFTN. AGAIN
MADE VERY MINOR CHANGES TO THE GOING FCST OF ISOLD TO SCT TSTMS.
17-18Z HX VALUES MAY PUSH 105F AT LNS AND MDT BUT WILL CONTINUE
WITH HEAT ADVY.
PREVIOUS DISCUSSION...
14-15Z...VISIBLE SATL LOOPS SHOW CU FIELD GOING UP ALONG ON THE
WRN AND CNTRL RIDGES...PARALLEL TO THE LLVL FLOW INDICATING BLYR
DESTABILIZATION. 14Z RUC ML CAPES ARE RUNNING BTWN 2-2.5K J/KG PER
SPC MESO PAGE. LATEST OBS STILL SHOW SOME 6-7SM HZ WITH SFC
DEWPOINTS IN THE LOW 70S. TEMPS SHOULD REACH THE LOW 90S IN THE
LWR SUSQ VLY BY 15Z WITH HEAT INDEXES APPROACHING 100F.
THE MAIN FCST CHALLENGE FOR TODAY CONTINUES TO BE FOCUSED ON THE
DEVELOPMENT/PLACEMENT OF DIURNAL CONVECTION. WITH AFTN TEMPS IN
THE UPPER 80S TO MID 90S AND SFC DEWPTS BTWN 65-70F...CAPES WILL
BE ROBUST AND EASILY SUPPORT UPDRAFTS. QUESTION REMAINS AS TO THE
EVOLUTION OF STORMS GIVEN NEBULOUS FORCING AND WARM 700MB TEMPS.
RAPID-REFRESH MESO MDL DATA IS STILL SHOWING THE GREATEST CVRG OF
TSTMS IN WRN/SWRN PA INTO WV. THIS MAY BE DUE TO A WK SHORTWAVE
ROTATING FROM KY INTO THE UPPER OH VLY ON THE NW PERIPHERY OF
RETREATING UPPER RIDGE. THE TERRAIN WILL ALSO ACT TO ENHANCE
LIFT. SOME CONVECTION IS ALSO PSBL NEAR THE LAKESHORE BOUNDARY
OVER THE NW MTNS. OVERALL...EXPECT ISOLD TO WDLY SCT TSTMS AS WE
GET LATER IN THE DAY. THE ENVIRONMENT SHOULD FAVOR MAINLY NON-SVR
MULTI-CELL STORMS GIVEN HIGH CAPE AND RELATIVELY WEAK 0-6KM SHEAR.
A HEAT ADVISORY REMAINS IN EFFECT FOR THE S-CENTRAL MTNS AND SUSQ
VLY UNTL 8PM. HEAT INDEXES/APPARENT TEMPERATURES ARE FCST TO REACH
THE 100 TO 104F RANGE...RESULTING IN AN ELEVATED RISK OF HEAT-
RELATED ILLNESS ESPECIALLY THOSE WITHOUT AC OR OUTDOORS FOR AN
EXTENDED PERIOD.
AFTN/EVE STORMS SHOULD WEAKEN INTO TONIGHT WITH THE LOSS OF
HEATING. IT WILL BE A WARM HUMID/MUGGY OVERNIGHT WITH INCREASED
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL SYSTEM - WHICH
SHOULD REACH THE ST. LAWRENCE VLY AND LWR LKS REGIONS BY DAYBREAK
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
BROAD CYCLONIC FLOW ALOFT ASSOCIATED WITH AN UPPER LEVEL TROUGH
WILL SPREAD SEWD FROM THE GREAT LAKES REGION ACRS THE OH VLY INTO
THE NRN APPLCHNS. A 60-75KT MID-LVL JET WILL MOVE THROUGH THE SE-
SIDE OF THE TROUGH ACRS QUEBEC. A COLD FRONT...CURRENTLY CROSSING
CENTRAL WI AND N-CENTRL LWR MI...SHOULD BE ACTIVE AT THE START OF
THE PERIOD WITH SHOWERS AND STORMS INVOF THE ST.LAWRENCE VLY SWWD
INTO THE LWR/ERN LAKES. AS THE COLD FRONT CONTINUES TO PUSH SEWD
INTO PA BY SAT AFTN...EXPECT CONVECTION TO EXPAND IN COVERAGE AND
INTENSITY WHICH WILL COINCIDE WITH SFC HEATING IN THE WARM SECTOR.
THE PRE-FRONTAL ENVIRONMENT WILL BE CHARACTERIZED BY MODERATE
INSTABILITY AND 30+ KTS OF 0-6KM SHEAR...WHICH SHOULD SUPPORT
ORGANIZED STORM STRUCTURES. THE UNIDIRECTIONAL WIND PROFILES
SUGGEST THE PRIMARY SEVERE STORM THREAT WILL BE DMGG WINDS WITH
SOME LARGE HAIL ALSO POSSIBLE WHERE STORMS CAN INGEST THE HIGH
CAPES. SPC HAS MAINTAINED A SLGT RISK OUTLOOK FOR SEVERAL DAYS
NOW AND EXPECT THIS TO PAN-OUT DURING THE DAY TOMORROW. THE WILD
CARD MAY BE THE DEVELOPMENT OF AN MCS WHICH COULD COMPLICATE
THINGS PRIOR TO FROPA.
SREF/GEFS PWAT FCSTS SUGGEST THE COLD FRONT WILL CLEAR THE NRN
ZONES BY 00Z BUT LINGER OVER SRN PA INTO SUNDAY MORNING. THEREFORE
KEPT LOW POPS ACRS THE SRN 1/2 TO 1/3 OF THE CWA LATE TONIGHT. AS
DRIER AIR ARRIVES BEHIND THE FRONT...LOOK FOR A COOLER...MORE
COMFORTABLE OVERNIGHT PERIOD OVER THE N-CNTRL MTNS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
SUNDAY SHOULD BE A POST FRONTAL DAY WITH PW VALUES NEAR TO
SLIGHTLY BELOW NORMAL. THE LOWER TROPOSPHERIC TEMPERATURES WILL BE
NEAR NORMAL TOO. THE CHANCE TO SHOWERS SHOULD BE LOW PERHAPS BEST
CHANCE IN SOUTHERNMOST AREAS CLOSE TO THE FRONTAL BOUNDARY.
OVERALL...SUNDAY IS LOOKING LIKE A VERY PLEASANT DAY FOR MOST
AREAS AS A WEAK AREA OF HIGH PRESSURE WILL BE OVER THE REGION. THE
LOWER HUMIDITY AND LOWER TEMPERATURES SHOULD BE WELCOME RELIEF.
THE LOW-LEVEL FRONTAL BOUNDARY DOES NOT PUSH TOO FAR TO OUR SOUTH.
THUS AS ANOTHER WAVE APPROACHES FROM THE WEST IT WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS.
THE NORTHWESTERLY FLOW WILL LIKELY PUSH A FRONT THROUGH THE REGION
AROUND MID-WEEK. THIS COULD INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS...MOST LIKELY ON WEDNESDAY. BEHIND THIS SECOND FRONT THE PW
VALUES DROP TO BELOW NORMAL...SHOULD BE VERY COMFORTABLE THURSDAY
AND FRIDAY BEHIND THIS FRONT SHOULD THESE FORECAST PROVE CLOSE TO
CORRECT.
OVERALL...THE MODELS AND ENSEMBLES ALL SHOW A TROUGH OVER THE
EASTERN USA MOST OF THE COMING WEEK IMPLYING COOLER AND RELATIVELY
DRIER WEATHER. BY MID-WEEK THE HEAT WAVE OF MID-JULY 2013 SHOULD
BE A FAINT MEMORY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CUMULUS WILL CONTINUE TO BUILD THRU THE AFTN WITH VISBYS IN
THE 6-8SM RANGE IN HZ DUE TO VERY MOIST BLYR /DEWPOINTS IN THE
UPPER 60S TO LOW 70S/. INCREASING INSTABILITY SHOULD COMBINE WITH
THE TERRAIN TO PROMOTE ISOLD TO SCT TSTM ACTIVITY WITH INITIATION
IN THE 17-20Z TIMEFRAME. WILL CONTINUE TO SHOW VCTS AND CB/S IN
THE TAFS GIVEN UNCERTAINTY IN EXACT LOCATION OF STORMS.
W/SW LLVL FLOW AHEAD OF APPROACHING COLD FRONT SHOULD LIMIT FOG/ST
FORMATION LATE TONIGHT...ESPECIALLY OVER THE WRN AREAS. ERN TAFS
HAVE A BETTER SHOT A GOING CLR/CALM SO COULD SEE SOME LCL
RESTRICTIONS BY DAYBREAK SATURDAY. THE COLD FRONT WILL CROSS THE
REGION LATER SATURDAY AND TRIGGER SCT STG TO SVR STORMS. THE WND
SHIFT SHOULD OCCUR FROM NW-SE BY SAT NIGHT.
OUTLOOK...
SAT...VFR. PM TSTM IMPACTS. SOME STORMS MAY BE SVR.
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...GRUMM/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...GRUMM/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1259 PM EDT FRI JUL 19 2013
.SYNOPSIS...
THE SUBTROPICAL RIDGE OVER THE EASTERN UNITED STATES WILL WEAKEN
AND SHIFT EASTWARD...YIELDING TO A VIGOROUS NORTHERN STREAM
SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES INTO THE NEW
ENGLAND. IT WILL BE UNSEASONABLY WARM UNTIL THE ASSOCIATED COLD
FRONTAL PASSAGE LATER SATURDAY. THE COLD FRONT COULD TRIGGER SOME
SEVERE THUNDERSTORMS. A BROAD UPPER LEVEL TROUGH SHOULD BUILD
OVER THE REGION FROM SUNDAY INTO NEXT WEEK. THIS PATTERN WILL
FEATURE A RETURN TO NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
17Z...TSTMS ARE DEVELOPING IN AREAS WHERE THE MESO MDLS HAD
PROJECTED - ON THE ELEVATED TERRAIN FROM NRN WV INTO SW PA AND
DOWNWIND OF LAKE ERIE. A FEW ISOLD CELLS ALSO FIRED OVER THE SE
PIEDMONT FROM NEAR MDT-LNS TO JUST NORTH OF RDG. STORM NEAR LNS
GREW QUICKLY TAPPING ABUNDANT CAPE (90/75 AT 16Z) WITH TOPS OVER
40KFT. THE LATEST RAPID-REFRESH HRRR SUGGEST A LINE OF STORMS MAY
DOWNWIND OF LAKE ERIE FROM NRN OH ACRS NW PA LATE THIS AFTN. AGAIN
MADE VERY MINOR CHANGES TO THE GOING FCST OF ISOLD TO SCT TSTMS.
17-18Z HX VALUES MAY PUSH 105F AT LNS AND MDT BUT WILL CONTINUE
WITH HEAT ADVY.
PREVIOUS DISCUSSION...
14-15Z...VISIBLE SATL LOOPS SHOW CU FIELD GOING UP ALONG ON THE
WRN AND CNTRL RIDGES...PARALLEL TO THE LLVL FLOW INDICATING BLYR
DESTABILIZATION. 14Z RUC ML CAPES ARE RUNNING BTWN 2-2.5K J/KG PER
SPC MESO PAGE. LATEST OBS STILL SHOW SOME 6-7SM HZ WITH SFC
DEWPOINTS IN THE LOW 70S. TEMPS SHOULD REACH THE LOW 90S IN THE
LWR SUSQ VLY BY 15Z WITH HEAT INDEXES APPROACHING 100F.
THE MAIN FCST CHALLENGE FOR TODAY CONTINUES TO BE FOCUSED ON THE
DEVELOPMENT/PLACEMENT OF DIURNAL CONVECTION. WITH AFTN TEMPS IN
THE UPPER 80S TO MID 90S AND SFC DEWPTS BTWN 65-70F...CAPES WILL
BE ROBUST AND EASILY SUPPORT UPDRAFTS. QUESTION REMAINS AS TO THE
EVOLUTION OF STORMS GIVEN NEBULOUS FORCING AND WARM 700MB TEMPS.
RAPID-REFRESH MESO MDL DATA IS STILL SHOWING THE GREATEST CVRG OF
TSTMS IN WRN/SWRN PA INTO WV. THIS MAY BE DUE TO A WK SHORTWAVE
ROTATING FROM KY INTO THE UPPER OH VLY ON THE NW PERIPHERY OF
RETREATING UPPER RIDGE. THE TERRAIN WILL ALSO ACT TO ENHANCE
LIFT. SOME CONVECTION IS ALSO PSBL NEAR THE LAKESHORE BOUNDARY
OVER THE NW MTNS. OVERALL...EXPECT ISOLD TO WDLY SCT TSTMS AS WE
GET LATER IN THE DAY. THE ENVIRONMENT SHOULD FAVOR MAINLY NON-SVR
MULTI-CELL STORMS GIVEN HIGH CAPE AND RELATIVELY WEAK 0-6KM SHEAR.
A HEAT ADVISORY REMAINS IN EFFECT FOR THE S-CENTRAL MTNS AND SUSQ
VLY UNTL 8PM. HEAT INDEXES/APPARENT TEMPERATURES ARE FCST TO REACH
THE 100 TO 104F RANGE...RESULTING IN AN ELEVATED RISK OF HEAT-
RELATED ILLNESS ESPECIALLY THOSE WITHOUT AC OR OUTDOORS FOR AN
EXTENDED PERIOD.
AFTN/EVE STORMS SHOULD WEAKEN INTO TONIGHT WITH THE LOSS OF
HEATING. IT WILL BE A WARM HUMID/MUGGY OVERNIGHT WITH INCREASED
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL SYSTEM - WHICH
SHOULD REACH THE ST. LAWRENCE VLY AND LWR LKS REGIONS BY DAYBREAK
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE CLOUDS WITH THE FRONT SHOULD KEEP IT A BIT COOLER SATURDAY
ESPECIALLY IN THE NORTHWESTERN AREAS. THE STRONG SOUTHWESTERLY
FLOW...HIGH PRECIPITABLE WATER VALUES AND RELATIVELY HIGH CAPE
IMPLY THAT THERE SHOULD BE THUNDERSTORMS SATURDAY FROM LATE
MORNING IN THE WEST TO LATER AFTERNOON IN THE SOUTHEAST. SOME OF
THESE STORMS COULD BE STRONG TO SEVERE. NEARLY ALL OF OUR AREA IS
IN SLIGHT RISK FOR SEVERE THUNDERSTORMS SATURDAY. THERE IS SOME
MODESTLY STRONG MOISTURE FLUX AT 850 HPA IMPLYING GOOD LIFT MOVING
ACROSS THE STATE FROM ABOUT 15Z TO 00Z.
MOST MODELS IMPLY THE DEEP MOISTURE PLUME IS PUSHED TO OUR EAST
SATURDAY EVENING. DRIER AIR MOVES IN LATE EVENING WITH COOLER AIR
BEHIND IT. SHOULD BECOME QUITE COMFORTABLE OVERNIGHT AND NOTICEABLY
COOLER LOWS ON SUNDAY MORNING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
SUNDAY SHOULD BE A POST FRONTAL DAY WITH PW VALUES NEAR TO
SLIGHTLY BELOW NORMAL. THE LOWER TROPOSPHERIC TEMPERATURES WILL BE
NEAR NORMAL TOO. THE CHANCE TO SHOWERS SHOULD BE LOW PERHAPS BEST
CHANCE IN SOUTHERNMOST AREAS CLOSE TO THE FRONTAL BOUNDARY.
OVERALL...SUNDAY IS LOOKING LIKE A VERY PLEASANT DAY FOR MOST
AREAS AS A WEAK AREA OF HIGH PRESSURE WILL BE OVER THE REGION. THE
LOWER HUMIDITY AND LOWER TEMPERATURES SHOULD BE WELCOME RELIEF.
THE LOW-LEVEL FRONTAL BOUNDARY DOES NOT PUSH TOO FAR TO OUR SOUTH.
THUS AS ANOTHER WAVE APPROACHES FROM THE WEST IT WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS.
THE NORTHWESTERLY FLOW WILL LIKELY PUSH A FRONT THROUGH THE REGION
AROUND MID-WEEK. THIS COULD INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS...MOST LIKELY ON WEDNESDAY. BEHIND THIS SECOND FRONT THE PW
VALUES DROP TO BELOW NORMAL...SHOULD BE VERY COMFORTABLE THURSDAY
AND FRIDAY BEHIND THIS FRONT SHOULD THESE FORECAST PROVE CLOSE TO
CORRECT.
OVERALL...THE MODELS AND ENSEMBLES ALL SHOW A TROUGH OVER THE
EASTERN USA MOST OF THE COMING WEEK IMPLYING COOLER AND RELATIVELY
DRIER WEATHER. BY MID-WEEK THE HEAT WAVE OF MID-JULY 2013 SHOULD
BE A FAINT MEMORY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CUMULUS WILL CONTINUE TO BUILD THRU THE AFTN WITH VISBYS IN
THE 6-8SM RANGE IN HZ DUE TO VERY MOIST BLYR /DEWPOINTS IN THE
UPPER 60S TO LOW 70S/. INCREASING INSTABILITY SHOULD COMBINE WITH
THE TERRAIN TO PROMOTE ISOLD TO SCT TSTM ACTIVITY WITH INITIATION
IN THE 17-20Z TIMEFRAME. WILL CONTINUE TO SHOW VCTS AND CB/S IN
THE TAFS GIVEN UNCERTAINTY IN EXACT LOCATION OF STORMS.
W/SW LLVL FLOW AHEAD OF APPROACHING COLD FRONT SHOULD LIMIT FOG/ST
FORMATION LATE TONIGHT...ESPECIALLY OVER THE WRN AREAS. ERN TAFS
HAVE A BETTER SHOT A GOING CLR/CALM SO COULD SEE SOME LCL
RESTRICTIONS BY DAYBREAK SATURDAY. THE COLD FRONT WILL CROSS THE
REGION LATER SATURDAY AND TRIGGER SCT STG TO SVR STORMS. THE WND
SHIFT SHOULD OCCUR FROM NW-SE BY SAT NIGHT.
OUTLOOK...
SAT...VFR. PM TSTM IMPACTS. SOME STORMS MAY BE SVR.
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...GRUMM/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...GRUMM/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
441 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND TRACK EAST THROUGH SATURDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTHWEST ON SUNDAY...STALLING
AND DISSIPATING IN THE VICINITY THROUGH EARLY NEXT WEEK. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE EAST TUESDAY AND
MOVE THROUGH THE AREA ON WEDNESDAY...WITH A SECOND WEAK COLD FRONT
ARRIVING FROM THE NORTHWEST FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
415 PM UPDATE...WILL MAINTAIN POPS LARGELY AS-IS. SPC MESOANALYSIS
SHOWS SBCAPE IN 2500-3500 J RANGE ACRS THE AREA. BEST COVERAGE ATTM
IS IN THE MTNS AND CONGESTED CU ARE ALIGNED ALONG RIDGETOPS SO THIS
COVERAGE IS STILL CAPABLE OF INCREASING FURTHER. REVISED PIEDMONT
POPS SUCH THAT BEST CHANCES ARE ALIGNED WITH THE BAND OF BETTER CU
FROM AROUND ELBERTON TO SALISBURY. THERE DOES APPEAR TO BE AN AREA
OF LOCAL SCALE SUBSIDENCE IN THE MIDLANDS SUPPRESSING CU GROWTH.
THIS IS WORKING NORTHWESTWARD...BUT THE CU IN THAT BAND ARE STILL
GROWING SO SOME CHANCE REMAINS IN THE PIEDMONT. 17Z HRRR DEVELOPS
CELLS AROUND SUNSET IN THE MTNS WHICH MARCH ACROSS THE NRN THIRD OF
THE CWFA THRU 03Z APPARENTLY ALONG AN OUTFLOW BOUNDARY. THIS IS
RATHER UNUSUAL BUT LAST NIGHT CELLS DID FIRE ALONG OUTFLOW IN THE
VERY MOIST AIR AT THAT TIME OF DAY. WILL MONITOR TRENDS IN SHORT
TERM GUIDANCE.
AT 220 PM EDT FRIDAY...AN UPPER TROUGH WILL SLOWLY AMPLIFY OVER THE
GREAT LAKES TONIGHT AND SATURDAY...WHILE AN ATLANTIC UPPER RIDGE
PROGRESSES FARTHER OUT TO SEA. MEANWHILE...A COLD FRONT WILL MOVE
SOUTHEAST...FROM THE UPPER MS RIVER VALLEY TO THE OH RIVER VALLEY.
LIGHT SSW LOW LEVEL FLOW WILL MAINTAIN RICH MOISTURE OVER OUR AREA
BELOW 700 MB. THE MODELS DISAGREE ON WEATHER THIS AFTERNOON OR
SATURDAY AFTERNOON WILL HAVE BETTER INSTABILITY...BUT ENOUGH SHOULD
BE PRESENT FOR SCATTERED CONVECTION EACH DAY...WITH THE BETTER
COVERAGE IN THE MOUNTAINS DUE TO OROGRAPHIC EFFECTS. WITH WEAK
SHEAR...STORM ORGANIZATION SHOULD BE LIMITED. STEERING FLOW IS
GENERALLY SHOWN TO BE LIGHT IN MODEL SOUNDINGS...SUGGESTING THAT
SLOW TRACKING STORMS COULD PRODUCE HEAVY PRECIPITATION...AND PERHAPS
ISOLATED FLASH FLOODING.
MINIMUM TEMPERATURES TONIGHT WILL BE ABOVE NORMAL TONIGHT IN A
MOIST ATMOSPHERE. MAXIMUM TEMPERATURES SATURDAY WILL BE SLIGHTLY
COOLER THAN TODAY AND NEAR NORMAL AS HEIGHTS FALL ALOFT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 215 PM EDT FRIDAY...AN UNSETTLED PERIOD IS SETTING UP FOR THE
SHORT TERM AS AN UPPER TROUGH AMPLIFIES OVER THE GREAT LAKES THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE SLOWLY SOUTHEAST FROM THE OHIO
VALLEY AND SETTLE OVER NORTH CAROLINA ON SUNDAY AFTERNOON AND THEN
MOVE NORTH AGAIN ON MONDAY. AS THE UPPER TROUGH AMPLIFIES TO THE
NORTH...A LIGHT ZONAL FLOW ALOFT WILL DEVELOP ON SUNDAY AND THEN
BECOME SW ON MONDAY AS A SHORT WAVE APPROACHES.
LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A DIURNAL
MODE...ESPECIALLY SAT NIGHT WHEN NO APPARENT FORCING WILL BE IN
PLACE TO MAINTAIN UPDRAFTS AFTER THE LOSS OF HEATING. HENCE...RAMPED
POPS DOWN QUICKLY SAT EVENING. ON SUN...SHOWERS/STORMS ARE EXPECTED
TO BECOME NUMEROUS AGAIN BY AFTERNOON OVER THE MOUNTAINS AS THE WEAK
FRONT DROPS INTO THE NORTHERN PORTION OF AREA. SHOULD SEE AT LEAST
SCT SHOWERS/THUNDERSTORMS ELSEWHERE AS SBCAPES APPROACH 1500J DURING
THE AFTERNOON. CONVECTION LOOKS LIKE IT WILL BE SLOWER TO ABATE SUN
NIGHT AS UPPER DIVERGENCE IMPROVES...BUT HAVE BACKED POPS DOWN
TO <15% OUTSIDE OF THE MOUNTAINS AFTER MIDNIGHT.
ON MONDAY...EXPECT ANOTHER DAY WHERE SHOWERS/THUDNERSTORMS WILL
BECOME NUMEROUS DURING THE AFTERNOON HOURS AS A SHORT WAVE
APPROACHES FROM THE WEST AND UPPER DIVERGENCE CONTINUES. USED A
CONSENSUS APPROACH TO GRID FIELDS. MAX TEMPS ARE FORECAST TO BE
ABOUT A CATEGORY SHY OF AVERAGE DUE TO INCREASED CLOUD COVER AND
PRECIP COVERAGE. LOWS WILL BE A LITTLE ABOVE AVERAGE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 200 PM EDT FRIDAY...BOTH THE ECMWF AND GFS INDICATE THAT A H5
TROF WILL START TO AMPLIFY ACROSS THROUGH SOUTHERN APPALACHIAN
REGION ON TUESDAY. A SHORT WAVE EMBEDDED IN THE TROF AXIS IS
EXPECTED TO RIPPLE ACROSS THE FORECAST AREA DURING THE HEAT OF TUES
AFTERNOON. FORECAST SOUNDINGS INDICATE THAT MILD MID LEVEL
TEMPERATURES WILL REMAIN OVER THE REGION...RESULTING CAPE VALUES OF
500-1000 J/KG. THE PASSAGE OF THE S/W COMBINED WITH THE POOL OF
MARGINAL CAPES TO SUPPORT INCREASING COVERAGE THROUGH THE AFTERNOON.
I WILL FORECAST LIKELY POPS ACROSS THE MTNS WITH HIGH CHC EAST. HIGH
TEMPERATURES UNDER DECREASING THICKNESSES AND PARTLY TO MOSTLY
CLOUDY SKY COVER SHOULD REMAIN A COUPLE OF DEGREES BELOW NORMAL.
WEDNESDAY AND THURSDAY...THE LONG WAVE TROUGH WILL REMAIN OVER THE
REGION. GFS FORECAST SOUNDINGS INDICATE THAT MID LEVEL TEMPERATURES
WILL SLOWLY COOL...RESULTING IN AN INCREASE IN CAPES FROM DAY TO
DAY. WEAK DISTURBANCES WILL LIKELY CONTINUE TO TRACK ACROSS THE
REGION...SUPPORTING SCT TO NUM SHRA/TSRA DURING THE EAST OF THE
AFTERNOON. THE GREATEST COVERAGE SHOULD OCCUR OVER THE MTNS.
TEMPERATURES SHOULD CONTINUE TO RANGE 2-3 DEGREES BELOW NORMAL.
FRIDAY...MEDIUM RANGE GUIDANCE INDICATES THAT THE L/W TROUGH AXIS
WILL PIVOT EAST OF THE CWA. DRIER AIR MAY ARRIVE FROM THE WEST...IN
THE WEAK OF A WEAK COLD FRONT. HOWEVER...MOISTURE WILL LIKELY LINGER
ACROSS THE FOOTHILLS AND PIEDMONT. GFS FORECAST SOUNDINGS CONTINUE
TO INDICATE MARGINAL DIURNAL CAPE ACROSS THE REGION. IT APPEARS THAT
AT LEAST SCT SHRA/TSRA WILL DEVELOP ALONG AND AHEAD OF THE SFC
BOUNDARY. I WILL FORECAST 30 TO 40 POPS ACROSS THE REGION.
TEMPERATURES WILL REMAIN COMPARABLE TO THE TUES THROUGH WED PERIOD.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...GUIDANCE IS NOT VERY SUPPORTIVE OF RESTRICTIONS...CARRYING
ONLY LOW VFR VSBY AT DAYBREAK SATURDAY. ROBUST INSTABILITY WILL
SUPPORT ENOUGH LATE AFTERNOON AND EARLY EVENING CONVECTION TO CARRY
A MENTION IN THE TAF...WITH MVFR CIG AND VSBY RESTRICTIONS POSSIBLE.
LIGHT SSW WINDS WILL PERSIST.
ELSEWHERE...A BLEND OF ADJMAV AND ADJMET GUIDANCE FAVORS MVFR VSBY
IN DAYBREAK FOG AT KAVL...WITH LOW VFR VSBY AT FOOTHILLS SITES. THE
BEST BET FOR CIGS WILL BE IN THE MOUNTAINS...WHERE MODEL TIME
HEIGHTS SUGGEST A BORDERLINE MVFR CIG AT KAVL THIS AFTERNOON/ OF
COURSE...ANY SITE THAT HAS A THUNDERSTORM MOVE OVERHEAD THIS
AFTERNOON OR EVENING WILL HAVE A CHANCE OF MVFR CIG AND VSBY
RESTRICTIONS DURING THE STORM...AND AGAIN AT DAYBREAK IN A RAIN
MOISTENED ATMOSPHERE. LIGHT WINDS WILL FAVOR THE SSW...EXCEPT IN THE
MOUNTAINS TONIGHT WHERE THEY WILL VEER TO THE NW TONIGHT.
OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND.
EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT
WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 98% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 96% HIGH 100%
KAVL LOW 56% LOW 53% MED 67% MED 61%
KHKY HIGH 100% HIGH 100% HIGH 86% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 96% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...GOODMAN
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LG
LONG TERM...GOODMAN/NED
AVIATION...JAT
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1231 PM CDT FRI JUL 19 2013
.DISCUSSION...
SEE AVIATION FOR THE 18Z TAF DISCUSSION.
&&
.AVIATION...
AT 17Z AN AREA OF SHOWERS AND THUNDERSTORMS WAS LOCATED OVER NORTHEAST
TEXAS MOVING SOUTHWEST AT 15 MPH. THE LATEST RUC13 AND EXTRAPOLATION
OF CURRENT MOVEMENT SUGGESTS CONVECTION WILL IMPACT KAUS AS EARLY AS
23Z. THUS WILL GO WITH A 3 HOUR TEMPO GROUP AT KAUS. ISOLATED CONVECTION
IS ALSO EXPECTED ALONG THE INLAND MOVING SEA-BREEZE BOUNDARY THIS
AFTERNOON. THE ISOLATED NATURE OF THIS ACTIVITY DOES NOT WARRANT
INCLUSION IN THE KSAT OR KSSF TAFS ATTM. OTHERWISE VFR CONDITIONS
WILL PREVAIL THIS AFTERNOON AND EVENING...WITH MVFR IN AND NEAR
TSTMS. MVFR CIGS WILL FORM AT THE I-35 TERMINALS BETWEEN 09Z AND
10Z...REACHING KDRT BY 11Z. CIGS WILL IMPROVE TO VFR BY 17Z WITH
ISOLATED AFTERNOON CONVECTION EAST OF A KBMQ...KSAT...KFTN LINE.
SFC WINDS WILL BE SOUTHERLY AT 5 TO 10 KTS WITH CONVECTIVE OUTFLOW
GUSTS OF 20 TO 30 KTS POSSIBLE THIS AFTERNOON AND EVENING.
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT FRI JUL 19 2013/
AVIATION...
STRATUS DECK ACROSS THE HILL COUNTRY AND ADJACENT AREAS WILL
CONTINUE TO EXPAND THROUGH THE NEAR-DAYBREAK HOURS. CIG BASES WILL
MOSTLY BE LOW MVFR WITH OCCASIONAL DROPS TO IFR BEFORE
LIFTING/SCATTERING OUT TO VFR AROUND 15-16Z AT KAUS/KSAT/KSSF AND
17Z AT KDRT. LIGHT SFC WINDS THIS MORNING WILL BECOME SE-SLY
MOSTLY AOB 10KTS THROUGH THE AFTERNOON. ISOLATED SHRA/TSRA ARE
POSSIBLE ACROSS FAR WESTERN PORTIONS OF THE REGION...AS WELL AS
GENERALLY EAST OF A LINE FROM KBMQ TO KHYI TO KVCT...MAINLY DURING
THE AFTERNOON HOURS. HOWEVER...AREAL COVERAGE IS TOO LOW TO WARRANT
EXPLICIT MENTION OF IMPACTS AT KAUS.
PREV DISCUSSION... /ISSUED 359 AM CDT FRI JUL 19 2013/
SHORT TERM (TODAY THROUGH SATURDAY)...
A THIN SUBTROPICAL RIDGE AXIS IS OVER SOUTH CENTRAL TEXAS BETWEEN
A TUTT LOW OVER THE CENTRAL GULF COAST AND AN UPPER LEVEL LOW OVER
SONORA STATE IN NORTHWESTERN MEXICO. AREA RADARS SHOW SCATTERED
SHOWERS OVER THE SERRANIAS DEL BURRO AND ISOLATED STREAMER SHOWERS
OVER THE COASTAL PLAINS. HAVE SLIGHT CHANCE POPS TODAY INTO THIS
EVENING FOR OUR EASTERN COUNTIES AS THE TUTT LOW APPROACHES WHILE
INTERACTING WITH THE SEABREEZE. ALSO HAVE POPS FOR OUR FAR WESTERN
AREA AS SOME STORMS MAY COME OFF THE SERRANIAS DEL BURROS. ON
SATURDAY...THE TUTT LOW MOVES A LITTLE FURTHER WEST TO THE UPPER
TEXAS COAST/SOUTHEASTERN TEXAS TO ENHANCE THE SEABREEZE. POPS
INCREASE TO LOW END CHANCE ACROSS THE EAST. HIGHS WARM SLIGHTLY
TODAY AND THEN LEVEL OFF MOST AREAS OR EVEN COOL SLIGHTLY IN THE
FAR EAST ON SATURDAY.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE TUTT LOW WEAKENS INTO A SHEAR AXIS OVER EASTERN INTO SOUTHERN
TEXAS BY SUNDAY WHILE A SHORT-WAVE ROTATES AROUND THE SONORAN
UPPER LOW TOWARD THE BIG BEND AND SLOWLY DEVELOPS INTO AN UPPER
LOW ITSELF LATE SUNDAY INTO MONDAY. THE ECMWF/UKMET DEPICT THIS
DEVELOPMENT OVER THE BIG BEND STRONGER WHILE THE GFS/GEM/NAVGEM
ARE MUCH WEAKER OR NON EXISTENT. WILL GO WITH AN IN BETWEEN
SOLUTION AND HAVE GONE WITH SLIGHT CHANCE POPS FOR ALL AREAS
SUNDAY AND AGAIN MONDAY. HOWEVER...POPS MAY HAVE TO BE RAISED WITH
INCREASING QPF OUT WEST IF THE STRONGER ECMWF/UKMET VERIFY. ON
TUESDAY...THE SUBTROPICAL RIDGE REASSERTS ITSELF WITH SLIGHT
CHANCE POPS ONLY IN THE FAR WEST. FOR THE REMAINDER OF NEXT WEEK
INTO NEXT WEEKEND...THE SUBTROPICAL RIDGE DOMINATES WITH NO POPS
AND ABOVE AVERAGE DAYTIME TEMPERATURES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 96 74 96 75 / 20 30 20 20 10
AUSTIN BERGSTROM INTL AIRPORT 71 96 71 96 73 / 20 20 20 20 10
NEW BRAUNFELS MUNI AIRPORT 70 95 71 96 72 / 10 20 10 20 10
BURNET MUNI AIRPORT 72 94 72 94 73 / 10 20 10 20 10
DEL RIO INTL AIRPORT 74 93 74 94 76 / 10 10 10 20 10
GEORGETOWN MUNI AIRPORT 72 95 72 94 73 / 20 30 20 20 10
HONDO MUNI AIRPORT 71 96 73 96 74 / 10 10 10 20 10
SAN MARCOS MUNI AIRPORT 71 95 72 96 74 / 20 20 10 20 10
LA GRANGE - FAYETTE REGIONAL 73 95 73 95 76 / 20 30 20 30 10
SAN ANTONIO INTL AIRPORT 74 95 74 95 76 / 10 20 10 20 10
STINSON MUNI AIRPORT 73 95 73 96 74 / 10 20 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...02
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
507 PM CDT FRI JUL 19 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 204 PM CDT FRI JUL 19 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LINE OF
CLOUDS EXTENDING FROM A PRE-FRONTAL TROUGH FROM LOWER MICHIGAN TO
NEBRASKA...WHICH EXITED THE AREA EARLIER THIS MORNING. THE MAIN
FOCUS CENTERS AROUND A COLD FRONT WHICH EXTENDS FROM WAUSAUKEE TO
MINNEAPOLIS. A LINE OF BUBBLY CU CONTINUES TO FIRE ALONG THE
FRONT...THOUGH CONVECTION IS WIDELY SCT AT BEST. DID HAVE ONE
STRONG STORM DEVELOP OVER THE SOUTHERN U.P. EARLIER THIS
AFTERNOON...BUT THE OTHER STORMS HAVE BEEN GARDEN VARIETY. GUSTY
WEST WINDS HAVE HELPED MIX DOWN DRIER AIR ALOFT OVER NORTH-CENTRAL
AND CENTRAL WISCONSIN...WHICH HAS KEPT THE INSTABILITY IN CHECK OVER
THESE AREAS. DEWPOINTS REMAIN IN THE LOW 70S FROM THE SOUTHERN FOX
VALLEY TO THE WEST SHORE OF THE BAY OF GREEN BAY WHERE ML CAPES ARE
UPWARDS OF 1.6K J/KG. DEWPOINTS HAVE BEEN FALLING JUST UPSTREAM OF
THE FOX VALLEY AT SHAWANO AND WAUPACA...SO THINK THIS TREND WILL
MOVE TO LOCATIONS FURTHER EAST. AS RESULT...THINK CHANCES OF SEVERE
STORMS DEVELOPING IS RELATIVELY LOW AND WILL JUST CARRY A SLIGHT
CHANCE OF STORMS FOR THE REST OF THE AFTERNOON. AS FOR THE HEAT
ADVISORY...SOME LOCATIONS FLIRTING WITH CRITERIA...BUT IN
GENERAL...HEAT INDEX READINGS ARE BELOW 95F. WITH DEWPOINTS FALLING
DUE TO MIXING...WILL CANCEL THE ADVISORY WITH THE AFTERNOON FORECAST
PACKAGE.
TONIGHT...ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR THE
FIRST COUPLE HOURS OF THE EVENING. THE THREAT OF PRECIP WILL
DIMINISH QUICKLY BY MID-EVENING...AND DRIER AIR WILL GRADUALLY
FILTER SOUTHEAST ACROSS THE REGION. THE MAIN PUSH OF COOLER AND
DRIER AIR WILL NOT ARRIVE UNTIL LATE TONIGHT WHEN A SECONDARY FRONT
SHIFTS SOUTH ACROSS THE NORTHERN THIRD OF THE STATE. UNTIL THAT
FRONT ARRIVES...THINK WILL SEE MOSTLY CLEAR TO PARTLY CLOUDY
CONDITIONS. LOWS RANGING FROM THE MIDDLE 50S NORTH TO THE MIDDLE
60S SOUTH.
SATURDAY...THE SECONDARY COLD FRONT WILL CONTINUE MOVE SOUTH ACROSS
CENTRAL WISCONSIN EARLY IN THE PERIOD AND THEN SETTLE OVER THE
SOUTHERN GREAT LAKES IN THE AFTERNOON. RIGHT REAR QUAD OF JET STREAK WILL
SWING FROM WEST-CENTRAL WISCONSIN TO SOUTHEAST WISCONSIN BUT THE
DEEPER MOISTURE WILL BE TIED UP ALONG THE COLD FRONT SO CENTRAL
WISCONSIN MAY JUST SEE A LITTLE MORE CU THAT THE REST OF THE
REGION. OTHERWISE...LIGHT NORTH WINDS WILL USHER IN DEWPOINTS IN
THE MID 40S TO MID 50S...WITH HIGHS MAINLY RANGING THROUGH THE 70S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 204 PM CDT FRI JUL 19 2013
UPPER PATTERN THIS PERIOD CHARACTERIZED BY MEAN TROF IN THE EAST
WITH RIDGE OVER THE WEST. RIDGE EXPECTED TO BUILD SOME OVER
ROCKIES LATER IN PERIOD. TIMING ISSUES LATER PERIODS CONTINUE WITH
MODELS...THOUGH TREND IS TOWARD HIGHEST PROBABILITY OF PCPN
MON/MON NIGHT. OP GFS COOLER AT END OF PERIOD THAN THAT SUGGESTED
BY 00Z ECMWF...THOUGH CURRENT ENSEMBLES FROM BOTH GFS AND ECMWF
TREND CLOSER TO GFS SOLUTION. HAVE STAYED WITH BLEND OF MODELS FOR
LATER PERIODS.
IN NEAR TERM...SFC HIGH TO SHIFT EAST WITH WARM FRONT MOVING INTO
SOUTHWEST WI SAT NIGHT. GIVEN LINGERING DRY AIR MASS WILL STAY
WITH INHERITED DRY FORECAST. WAA REGIME CONTINUES SUN INTO MONDAY
AHEAD OF FRONT EXPECTED TO MOVE THROUGH LATER MONDAY. MUCH OF GULF
MOISTURE TIED TO FRONT TO SOUTH OF AREA. MODELS NOT SHOWING MUCH
IN THE WAY OF INSTABILITY...SOME WEAK ELEVATED INSTABILITY
PRESENT. WENT MORE WITH SHOWERS...ISOLATED THUNDER AT BEST.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 507 PM CDT FRI JUL 19 2013
A COLD FRONT WILL CONTINUE TO SLIDE SOUTH OVER THE
SOUTHEAST HALF OF WISCONSIN THIS EVENING. ISOLATED SHOWERS OR
STORMS WILL LINGER THROUGH EARLY EVENING OVER EAST CENTRAL
WISCONSIN. COOLER AND DRIER AIR WILL FILTER INTO THE REGION ON
NORTHWEST WINDS GUSTING TO 20 KNOTS EARLY THIS EVENING. OTHERWISE
VFR CONDITIONS EXPECTED TONIGHT INTO SATURDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
330 PM CDT FRI JUL 19 2013
.SHORT TERM...
LATE THIS AFTERNOON...TONIGHT AND SATURDAY...FORECAST CONFIDENCE IS
MEDIUM TO HIGH.
MAIN ISSUE WILL BE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS AS
COLD FRONT SLIDES SOUTHEAST THROUGH THE AREA THROUGH EARLY THIS
EVENING. CUMULUS LINE FORMING ALONG FRONT TO THE NORTHWEST OF THE
FORECAST AREA. UPWARD VERTICAL MOTION IS WEAK TO MODEST WITH FRONT
AS IT PASSES THROUGH THE AREA...WITH WEAK TO MODEST 500MB VORTICITY
MAXIMUM TRAILING THE FRONT.
CAP ALMOST MIXED OUT IN SOUTHEAST COUNTIES WITH LOWER TO MID 90S
TEMPERATURES...WITH SLIGHTLY COOLER TEMPERATURES ALLOWING FOR A BIT
MORE CAPPING TO THE NORTHWEST. LATEST HRRR/WRF 4KM WITH LAPS AGREE
ON A BROKEN LINE OF SHOWERS AND THUNDERSTORMS MOVING THROUGH THE
AREA WITH THE FRONT. BEST CHANCES PROBABLY WILL BE IN THE FAR EAST
AND OVER LAKE MICHIGAN...AS FRONT INTERACTS WITH COOL LAKE AIRMASS
AND RESULTS IN ENHANCED UPWARD VERTICAL MOTION.
WENT WITH SCATTERED POPS IN FORECAST THROUGH EARLY EVENING FROM
NORTHWEST TO SOUTHEAST ACROSS THE AREA...AS THERE IS SOME
UNCERTAINTY WITH THE AREAL COVERAGE GIVEN THE WEAK TO MODEST UPWARD
VERTICAL MOTION.
SPC HAS MAINLY THE SOUTHEAST HALF OF THE AREA IN SLIGHT RISK FOR
SEVERE STORMS THROUGH EARLY EVENING. RAP AREA FORECAST SOUNDINGS
INDICATE AROUND 2500 J/KG MEAN LAYER CAPE WITH AROUND 30 KNOTS OF 0
TO 6 KM SHEAR AND FAIRLY HIGH PRECIPITABLE WATER VALUES. THIS SHOULD
ALLOW FOR SOME STRONG TO SEVERE STORMS TO DEVELOP. DAMAGING WINDS
AND LARGE HAIL WOULD BE THE MAIN HAZARDS.
KEPT HEAT ADVISORY GOING UNTIL 00Z SATURDAY ACROSS THE
AREA...DESPITE MIXY CONDITIONS KEEPING DEW POINTS IN THE 60S IN
PORTIONS OF THE AREA. HEAT INDEX VALUES WILL STILL BE IN THE 95 TO
102 RANGE.
COLD AIR ADVECTION THEN BRINGS COOLER AND DRIER AIRMASS INTO THE
REGION BEHIND FRONT FROM MID EVENING THROUGH SATURDAY...AS HIGH
PRESSURE BUILDS INTO THE REGION FROM THE NORTHWEST.
BACKDOOR COLD FRONT DOES SLIDE SOUTHWARD THROUGH THE AREA
SATURDAY...FIRST DOWN THE LAKESHORE THEN IN THE WEST LATER IN THE
DAY. NORTHEAST WINDS AFTER THE FRONTAL PASSAGE WILL BRING COOLER
TEMPERATURES...ESPECIALLY NEAR THE LAKE. KEPT DRY FORECAST AS
AIRMASS IS FAIRLY DRY DESPITE WEAK INSTABILITY IN FORECAST
SOUNDINGS.
SATURDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM
WEAK VORTICITY MAXIMUMS WITHIN NW FLOW ALOFT WILL MOVE ACROSS THE
REGION DURING THIS PERIOD. A SLIGHTLY MORE ORGANIZED SHORTWAVE
TROUGH WILL PASS THROUGH IA...IL...AND SRN WI FOR SUNDAY
AFTERNOON THROUGH THE NIGHT BUT LOOKS THE MOST ORGANIZED TO THE
SOUTH. PWS HOWEVER COULD INCREASE TO 1.5 INCHES WITH THIS FEATURE.
MAINTAINING CHANCE POPS FOR THIS BUT IF UPPER WAVE BECOMES
STRONGER WITH GIVEN MOISTURE...THEN RAIN COVERAGE AND INTENSITY
WOULD BE HIGHER. WITH MORE HUMID CONDITIONS RETURNING AND SCT-BKN
CLOUD COVER...KEPT MILD LOW TEMPS FOR THIS PERIOD. ONSHORE FLOW
WILL KEEP FAR ERN WI RELATIVELY COOL FOR SAT BUT INLAND TEMPS MORE
CHALLENGING. DID ACCOUNT FOR SOME SUNSHINE IN HIGHS FOR SAT.
SUBSIDENCE FROM DEPARTING SHORTWAVE TROUGH FOR MON SHOULD RESULT
IN MORE SUNSHINE. IN ADDITION...SSWLY WINDS AND WEAK WARM ADVECTION
AHEAD OF LOW PRESSURE TRACKING ACROSS SRN CANADA SHOULD ALSO HELP
BOOST HIGH TEMPS INTO THE MID 80S AWAY FROM THE LAKE. ONLY A
SLIGHT CHANCE OF TSTORMS IS FORECAST TO ACCOUNT FOR SLOWER
SHORTWAVE TROUGH MOVEMENT OR A FASTER MOVEMENT OF THE COLD FRONT
THAT EXTENDS FROM THE CANADIAN LOW. LOW POPS ARE THEN FORECAST FOR
THE COOL FROPA MON NT AND TUE.
.LONG TERM...
WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
EXTENDED MODELS DUE SHOW A MORE ORGANIZED SFC HIGH PRESSURE AREA
TO COME INTO THE GREAT LAKES REGION FOR WED AND THU AND POSSIBLY
EXTENDING THROUGH FRI. WENT DRY WITH THE EXCEPTION OF THE FAR WRN
CWA FOR FRI. PLEASANT WITH NEAR NORMAL TEMPS AND HUMIDITY EXPECTED.
&&
.AVIATION/00Z TAFS/...VFR CONDITIONS ARE EXPECTED ACROSS TAF SITES
TONIGHT AND SATURDAY. GUSTY SOUTHWEST TO WEST WINDS ARE EXPECTED
UNTIL SUNSET...WITH FREQUENT GUSTS IN THE 20 TO 25 KNOT RANGE. SOME
DIURNAL CUMULUS WILL DEVELOP AS MID LEVEL CLOUDS MOVE THROUGH AND
EAST OF THE AREA.
SCATTERED SHOWERS AND STORMS ARE EXPECTED WITH THE COLD FRONTAL
PASSAGE LATER THIS AFTERNOON...ENDING EARLY THIS EVENING AS FRONT
MOVES OUT OF THE AREA. LEFT VICINITY THUNDER WORDING IN TAFS TO
ACCOUNT FOR THIS...WITH BRIEF MVFR VISIBILITIES AND GUSTY WINDS
POSSIBLE IN ANY STORMS. AREAL COVERAGE IS UNCERTAIN...SO COULD END
UP BEING DRY AT TAF SITES.
WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT BY MID
EVENING...WITH SKIES CLEARING OUT TONIGHT WITH COOLER AND DRIER
AIRMASS MOVING IN. WINDS WILL SHIFT NORTH AND THEN NORTHEAST BY
SATURDAY AFTERNOON...AS BACKDOOR COLD FRONT MOVES SOUTHWARD THROUGH
THE AREA. MOSTLY CLEAR SKIES ARE EXPECTED SATURDAY AT THE EASTERN
SITES...WITH SOME DIURNAL CUMULUS AT MADISON DURING THE AFTERNOON.
&&
.MARINE...SMALL CRAFT ADVISORY WILL CONTINUE UNTIL 00Z SATURDAY
ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. TIGHT PRESSURE
GRADIENT AND MIXING WITH DAYTIME HEATING WILL CONTINUE TO BRING
GUSTY SOUTHWEST TO WEST WINDS ACROSS THIS AREA THROUGH THE REST OF
THE DAY. GUSTS IN THE MID 20 KNOT RANGE ARE EXPECTED AT TIMES.
OFFSHORE FLOW WILL KEEP ANY HIGH WAVES OVER THE OPEN WATERS. THE
GUSTS WILL SUBSIDE BY EVENING...WITH A WEAKENING PRESSURE GRADIENT
WITH THE PASSING COLD FRONT.
BACKDOOR COLD FRONT WILL PUSH SOUTHWARD ACROSS THE NEARSHORE WATERS
OF LAKE MICHIGAN SATURDAY MORNING...WITH A QUICK WIND SHIFT TO THE
NORTHEAST BEHIND IT. WINDS MAY BE GUSTING UP TO 15 KNOTS OR SO FOR
AN HOUR OR TWO AFTER THE FRONTAL PASSAGE...THEN REMAIN IN THE 10 TO
15 KNOT RANGE THROUGH THE REST OF THE DAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/SATURDAY AND AVIATION/MARINE...WOOD
SATURDAY NIGHT THROUGH FRIDAY...GEHRING
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 204 PM CDT FRI JUL 19 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LINE OF
CLOUDS EXTENDING FROM A PRE-FRONTAL TROUGH FROM LOWER MICHIGAN TO
NEBRASKA...WHICH EXITED THE AREA EARLIER THIS MORNING. THE MAIN
FOCUS CENTERS AROUND A COLD FRONT WHICH EXTENDS FROM WAUSAUKEE TO
MINNEAPOLIS. A LINE OF BUBBLY CU CONTINUES TO FIRE ALONG THE
FRONT...THOUGH CONVECTION IS WIDELY SCT AT BEST. DID HAVE ONE
STRONG STORM DEVELOP OVER THE SOUTHERN U.P. EARLIER THIS
AFTERNOON...BUT THE OTHER STORMS HAVE BEEN GARDEN VARIETY. GUSTY
WEST WINDS HAVE HELPED MIX DOWN DRIER AIR ALOFT OVER NORTH-CENTRAL
AND CENTRAL WISCONSIN...WHICH HAS KEPT THE INSTABILITY IN CHECK OVER
THESE AREAS. DEWPOINTS REMAIN IN THE LOW 70S FROM THE SOUTHERN FOX
VALLEY TO THE WEST SHORE OF THE BAY OF GREEN BAY WHERE ML CAPES ARE
UPWARDS OF 1.6K J/KG. DEWPOINTS HAVE BEEN FALLING JUST UPSTREAM OF
THE FOX VALLEY AT SHAWANO AND WAUPACA...SO THINK THIS TREND WILL
MOVE TO LOCATIONS FURTHER EAST. AS RESULT...THINK CHANCES OF SEVERE
STORMS DEVELOPING IS RELATIVELY LOW AND WILL JUST CARRY A SLIGHT
CHANCE OF STORMS FOR THE REST OF THE AFTERNOON. AS FOR THE HEAT
ADVISORY...SOME LOCATIONS FLIRTING WITH CRITERIA...BUT IN
GENERAL...HEAT INDEX READINGS ARE BELOW 95F. WITH DEWPOINTS FALLING
DUE TO MIXING...WILL CANCEL THE ADVISORY WITH THE AFTERNOON FORECAST
PACKAGE.
TONIGHT...ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR THE
FIRST COUPLE HOURS OF THE EVENING. THE THREAT OF PRECIP WILL
DIMINISH QUICKLY BY MID-EVENING...AND DRIER AIR WILL GRADUALLY
FILTER SOUTHEAST ACROSS THE REGION. THE MAIN PUSH OF COOLER AND
DRIER AIR WILL NOT ARRIVE UNTIL LATE TONIGHT WHEN A SECONDARY FRONT
SHIFTS SOUTH ACROSS THE NORTHERN THIRD OF THE STATE. UNTIL THAT
FRONT ARRIVES...THINK WILL SEE MOSTLY CLEAR TO PARTLY CLOUDY
CONDITIONS. LOWS RANGING FROM THE MIDDLE 50S NORTH TO THE MIDDLE
60S SOUTH.
SATURDAY...THE SECONDARY COLD FRONT WILL CONTINUE MOVE SOUTH ACROSS
CENTRAL WISCONSIN EARLY IN THE PERIOD AND THEN SETTLE OVER THE
SOUTHERN GREAT LAKES IN THE AFTERNOON. RIGHT REAR QUAD OF JET STREAK WILL
SWING FROM WEST-CENTRAL WISCONSIN TO SOUTHEAST WISCONSIN BUT THE
DEEPER MOISTURE WILL BE TIED UP ALONG THE COLD FRONT SO CENTRAL
WISCONSIN MAY JUST SEE A LITTLE MORE CU THAT THE REST OF THE
REGION. OTHERWISE...LIGHT NORTH WINDS WILL USHER IN DEWPOINTS IN
THE MID 40S TO MID 50S...WITH HIGHS MAINLY RANGING THROUGH THE 70S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 204 PM CDT FRI JUL 19 2013
UPPER PATTERN THIS PERIOD CHARACTERIZED BY MEAN TROF IN THE EAST
WITH RIDGE OVER THE WEST. RIDGE EXPECTED TO BUILD SOME OVER
ROCKIES LATER IN PERIOD. TIMING ISSUES LATER PERIODS CONTINUE WITH
MODELS...THOUGH TREND IS TOWARD HIGHEST PROBABILITY OF PCPN
MON/MON NIGHT. OP GFS COOLER AT END OF PERIOD THAN THAT SUGGESTED
BY 00Z ECMWF...THOUGH CURRENT ENSEMBLES FROM BOTH GFS AND ECMWF
TREND CLOSER TO GFS SOLUTION. HAVE STAYED WITH BLEND OF MODELS FOR
LATER PERIODS.
IN NEAR TERM...SFC HIGH TO SHIFT EAST WITH WARM FRONT MOVING INTO
SOUTHWEST WI SAT NIGHT. GIVEN LINGERING DRY AIR MASS WILL STAY
WITH INHERITED DRY FORECAST. WAA REGIME CONTINUES SUN INTO MONDAY
AHEAD OF FRONT EXPECTED TO MOVE THROUGH LATER MONDAY. MUCH OF GULF
MOISTURE TIED TO FRONT TO SOUTH OF AREA. MODELS NOT SHOWING MUCH
IN THE WAY OF INSTABILITY...SOME WEAK ELEVATED INSTABILITY
PRESENT. WENT MORE WITH SHOWERS...ISOLATED THUNDER AT BEST.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1233 PM CDT FRI JUL 19 2013
A COLD FRONT WILL DROP SOUTHEAST ACROSS CENTRAL AND
NORTHEAST WISCONSIN THIS AFTERNOON. STORMS HAVE FIRED ALONG THE
FRONT OVER FAR NORTHERN WISCONSIN AND THE UPPER PENINSULA BUT MIXING
OF DRIER AIR TO THE SURFACE HAS LIMITED THE STORMS INTENSITY.
ADDITIONAL STORMS ARE EXPECTED TO FIRE THIS AFTERNOON AND SOME COULD
PRODUCE STRONG GUSTY WINDS. CLEARING IS EXPECTED BEHIND THE COLD
FRONT THIS EVENING WITH GOOD FLYING WEATHER TONIGHT THROUGH SATURDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1203 PM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT FRI JUL 19 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE WESTERN U.S. AS WELL AS OVER THE
MID-ATLANTIC...WHILE TROUGHING WAS IN-BETWEEN FROM SOUTH CENTRAL
CANADA INTO WESTERN MN. THIS TROUGHING IS COMPOSED OF A POTENT
SHORTWAVE OVER MANITOBA...A SHORTWAVE FROM CENTRAL NORTH DAKOTA INTO
NORTHERN MN...AND A DEEP DRY-SLOT AHEAD OF THE SHORTWAVE FROM SOUTH
DAKOTA INTO WESTERN LAKE SUPERIOR. A COLD FRONT AT THE SURFACE WAS
ANALYZED FROM NEAR SIOUX FALLS TO THUNDER BAY ONTARIO...SLIGHTLY
AHEAD OF THE DRY SLOT. AMAZINGLY...DESPITE 4000 J/KG OF SBCAPE AND
LITTLE CIN ON THE 00Z ABR SOUNDING...THE FRONT WENT THROUGH THERE
WITH LITTLE ACTIVITY. BEST GUESS WAS THE LACK OF CONVERGENCE ON THE
FRONT...WHICH WAS REPRESENTED WELL ON 0-2KM RAP CONVERGENCE PLOTS.
FRONT IS MORE ACTIVE NOW...MORESO THE WARM ADVECTION AHEAD OF
IT...WITH HIGHER BASED SHOWERS AND THUNDERSTORMS FROM FARMINGTON MN
TO PARK FALLS WI. WARM AIR CONTINUES TO HOLD STRONG IN THE WARM
SECTOR WITH READINGS IN THE UPPER 70S / LOW 80S...THANKS IN PART TO
A 30-45 KT 925MB WINDS OVER THE AREA. THERE IS EVEN WARMER AIR
FLOWING IN FROM THE WEST ALONG THE FRONT...OBSERVED ON THE 00Z ABR
SOUNDING WITH AN 800MB TEMP OF 20C AND 925MB TEMP OF 30C...COMPARED
TO 17C AND 27C RESPECTIVELY FROM THE 00Z MPX SOUNDING. BEHIND THE
FRONT...925MB TEMPS ARE NOT THAT MUCH COOLER WITH 28C OBSERVED AT
GGW...BUT DEWPOINTS DROP INTO THE 50S AND LOW 60S.
SYNOPTIC OVERVIEW...
UPPER TROUGHING IS STILL POISED TO FORM OVER THE WESTERN GREAT LAKES
REGION BY 06Z TONIGHT...THOUGH THE MORE POTENT SHORTWAVE COMPOSING
THE TROUGH IS FORECAST TO STAY UP IN CANADA. MEANWHILE...THE
SHORTWAVE SEEN UP IN CENTRAL NORTH DAKOTA IS SLATED TO DROP INTO
CENTRAL MN BY 18Z...THEN PUSH EAST INTO LOWER MI. WITH THE UPPER
TROUGHING FORMING...EXPECT THE COLD FRONT TO CONTINUE MARCHING
SOUTHEAST. MODEL TIMING IS WELL AGREED UPON...AT 18Z STRETCHING FROM
OMAHA NEB TO VOLK FIELD WI AND MARINETTE WI...AND AT 00Z FROM
NORTHWEST MO TO NEAR DUBUQUE IA AND UP TO MANITOWOC WI.
HAZARDS...
ONGOING HEAT ADVISORY...DUE TO FRONTAL TIMING AND DRYING DEWPOINTS
BEHIND THE FRONT...HAVE CANCELLED SOME OF THE ADVISORY. AREAS
INCLUDE SOUTHEAST MN AND PORTIONS OF NORTHEAST IOWA INTO CENTRAL WI.
THERE ALSO IS A CHANCE FOR SEVERE WEATHER THIS AFTERNOON ALONG THE
COLD FRONT COMING THROUGH NORTHEAST IOWA AND SOUTHWEST WI. 0-6KM
SHEAR VALUES ARE HIGHER IN THE 09.00Z NAM...ORDER OF 30-40 KT VERSUS
20-30 KT IN THE 09.06Z RAP. IF SEVERE WEATHER OCCURS...DAMAGING
WINDS WOULD BE THE MAIN HAZARDS.
TODAY...
TWO BIG QUESTIONS...TEMPERATURES AND PRECIPITATION CHANCES. ON THE
PRECIPITATION SIDE OF THINGS...19.00Z GFS/NAM/REGIONAL CANADIAN ALL
WANT TO BRING THE SHOWERS AND SOME THUNDERSTORMS THROUGH THE
FORECAST AREA THIS MORNING PRIOR TO THE FRONTAL PASSAGE. THESE
ORIGINATE FROM ISENTROPIC LIFT ON THE 310 K SURFACE AHEAD OF THE
FRONT. IT APPEARS THESE SHOULD WEAKEN THROUGH THE MORNING TOO WITH
THE NOCTURNAL LOW LEVEL JET WEAKENING. A PERIOD OF CLEARING THEN
TAKES PLACE IN THE WARM SECTOR...WITH SOME HINTS FROM THE 19.00Z
GFS/REGIONAL CANADIAN AND 19.06Z RAP THAT THE FRONT COULD CONVECT IN
SOUTHEASTERN PORTION OF THE FORECAST AREA SAY BETWEEN 19-23Z. NOT
THRILLED ABOUT THE FRONT CONVECTING AS THE 0-2KM CONVERGENCE IS VERY
WEAK. HOWEVER...GIVEN MODELS HAVE BEEN SHOWING IT THE PAST FEW DAYS
AND PLENTY OF INSTABILITY PROGGED TO DEVELOP TODAY...KEPT SOME
CHANCES IN THE FORECAST. HAVE ALSO ADDED SOME LOW CHANCES OF
PRECIPITATION FOR THE AFTERNOON HOURS FROM TAYLOR COUNTY SOUTH TO
JACKSON. HERE ANOTHER FRONT LURKING UP IN NORTHERN MN IS PROGGED BY
THE 09.06Z RAP AND 09.05Z HRRR TO COME THROUGH AND HAVE SOME
CONVECTION ON IT. ON THE TEMPERATURE SIDE OF THINGS...A WARM START
PLUS 925MB TEMPS HOLDING IN THE 24-26C RANGE SHOULD EASILY ALLOWS
HIGHS TO REACH THE UPPER 80S TO POSSIBLY MID 90S AGAIN. THIS IS EVEN
DESPITE THE FRONTAL PASSAGE GIVEN THE WARM AIR STILL HOLDING BACK
AND LIKELY DEEPER MIXING BEHIND THE FRONT. HOWEVER...HEAT INDICES
WILL FALL WITH THE FRONT AS DRIER DEWPOINTS FLOW IN.
TONIGHT...
SUBSIDENCE AND DRYING COMING IN BEHIND THE COLD FRONT WILL ALLOW FOR
A MOSTLY CLEAR NIGHT ACROSS THE FORECAST AREA. DRIER AIR AND
DIMINISHING WINDS SHOULD ALLOW TEMPERATURES TO FALL CLOSE TO
GUIDANCE VALUES...IN THE UPPER 50S TO MID 60S...10-15 DEGREES COLDER
THAN TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM CDT FRI JUL 19 2013
SYNOPTIC OVERVIEW...
MUCH OF THE NEXT 6 DAYS LOOKS TO BE DOMINATED BY NORTHWEST FLOW
ACCORDING TO THE 19.00Z ECMWF/GFS/CANADIAN WITH RIDGING STAYING PUT
OVER THE WESTERN U.S.. THERE ARE SOME SIGNS FROM THE ECMWF THE RIDGE
MAY WANT TO BUILD EAST TOWARDS THE FORECAST AREA ON THURSDAY...BUT
PLENTY OF UNCERTAINTY ON THAT SEEING THE TROUGHING IN THE GFS.
ADDITIONALLY...THIS NORTHWEST FLOW HAS UNCERTAINTY IN TERMS OF
TIMING SHORTWAVES AND THE CHANCES OF PRECIPITATION WITH THEM.
SATURDAY THROUGH SUNDAY NIGHT...
MAIN FEATURE OF INTEREST DURING THIS PERIOD IS A SHORTWAVE ALL
MODELS HAVE TRACKING OUT OF MONTANA ON SATURDAY AND THROUGH THE
FORECAST AREA ON SUNDAY. SURPRISINGLY MODELS ARE IN REALLY GOOD
AGREEMENT WITH THIS SHORTWAVE...ALBEIT PERHAPS THE GFS HAS A BIT OF
CONVECTIVE FEEDBACK TO IT. IN ANY EVENT...INCREASING 310 K
ISENTROPIC LIFT COMBINED WITH INSTABILITY SHOULD INITIATE CONVECTION
OVER EASTERN SOUTH DAKOTA DURING THE AFTERNOON. THIS CONVECTION THEN
SPREADS TOWARDS THE FORECAST AREA SATURDAY NIGHT AS THE ISENTROPIC
LIFT AND 850MB MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE SHIFTS
EAST. PERHAPS THERE IS A SHOT SOME HIGH BASED SHOWERS COULD DEVELOP
DOWNSTREAM OF THE CONVECTION SATURDAY AFTERNOON...BUT THINK THE BULK
OF THE PRECIPITATION WOULD WAIT UNTIL SATURDAY NIGHT. SUNDAY APPEARS
TO HAVE THE HIGHEST CHANCE OF RAIN WHERE DPVA ACCOMPANYING THE
SHORTWAVE INTERSECTS 850MB MOISTURE TRANSPORT CONTINUING TO AIM AT
THE AREA. ITS HARD TO SAY HOW SUNDAY NIGHT WILL EVOLVE. SUBSIDENCE
BEHIND THE SHORTWAVE MOVING THROUGH ON SUNDAY WOULD SEEM TO LIKELY
PROVIDE A DRY PERIOD...LIKE SUGGESTED BY THE 19.00Z NAM. HOWEVER...
THE 19.00Z GFS/ECMWF SHOW A POTENT SHORTWAVE TROUGH CROSSING
SOUTHERN MANITOBA SUNDAY NIGHT...WHICH INCREASES 850MB MOISTURE
TRANSPORT INTO THE AREA. THEREFORE...THESE MODELS WANT TO HANG ONTO
SOME SHOWERS. HAVE MAINTAINED SOME CHANCES OF PRECIPITATION TO
ACCOUNT FOR THE GFS/ECMWF SCENARIO. BIGGEST ISSUE IN THE TEMPERATURE
DEPARTMENT IS HIGHS ON SUNDAY. IF IT RAINS ALL DAY...TEMPERATURES
MAY GET STUCK IN THE UPPER 60S/LOW 70S. FOR NOW TRENDED HIGHS DOWN
SLIGHTLY.
MONDAY THROUGH THURSDAY NIGHT...
THIS PERIOD IS HIGHLY UNCERTAIN. 19.00Z GFS/ECMWF/CANADIAN SHOW
NUMEROUS SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT THROUGH
MUCH OF THE WEEK. TIMING AND TRACK OF THESE VARIES FROM RUN TO
RUN...THUS THE LOW CONFIDENCE. THERE DOES APPEAR TO BE SOME SIGNAL
FOR A COLD FRONT COMING THROUGH THE FORECAST AREA MONDAY
NIGHT...ASSOCIATED WITH THAT POTENT TROUGH OVER SOUTHERN MANITOBA
PROGGED TO LIFT EAST-NORTHEAST. IF THIS STAYS CONSISENT...WE MIGHT
BE ABLE TO DRY OUT TUESDAY. OTHERWISE...HAVE MAINTAINED A MODEL
CONSENSUS OF 20-40 PERCENT CHANCES THROUGH THURSDAY NIGHT. LIKELY
THE ENTIRE PERIOD WILL NOT BE WET...BUT HARD TO PIN POINT MUCH FOR
POSSIBLE DRY PERIODS BEYOND TUESDAY. WITH A NORTHWEST FLOW IN
PLACE...EXPECT A COOLER FLOW OF AIR. 850MB TEMPS ARE GENERALLY
PROGGED TO DROP FROM 18-20C ON MONDAY TO 12-15C FOR TUESDAY THROUGH
THURSDAY. THESE SHOULD RESULT IN A DROP IN HIGHS TO SLIGHTLY BELOW
NORMAL AFTER NEAR NORMAL ON MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1203 PM CDT FRI JUL 19 2013
COLD FRONT MAKING STEADY SOUTHEASTWARD PROGRESS THROUGH THE AREA.
IT HAS ALREADY PASSED THROUGH KRST AND SHOULD BE THROUGH KLSE BY
OR JUST AFTER 18Z. WILL THUS START BOTH SITES WITH SOME GUSTY
NORTHWEST WINDS. THE WINDS EXPECTED TO DIE DOWN EARLY IN THE
EVENING AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST RELAXING THE
GRADIENT. NOT EXPECTING ANY FOG TO FORM OVERNIGHT AT KLSE AS THE
NORTHWEST WINDS WILL BRING IN DRIER AIR WITH DEW POINTS EXPECTED
TO DROP INTO THE LOWER 60S MAINTAINING A TEMP/DEW POINT SPREAD OF
AT LEAST 4 DEGREES THROUGH THE NIGHT.
&&
.CLIMATE...
ISSUED AT 321 AM CDT FRI JUL 19 2013
LA CROSSE WI HAS ONLY SEEN 0.27 INCHES FOR THE MONTH OF JULY
THROUGH THE 18TH. THIS IS THE 5TH DRIEST START TO JULY. THE DRIEST
THROUGH JULY 18TH WAS 0.05 INCHES BACK IN 1896...AND THE LAST TIME
IT WAS THIS DRY WAS IN 1967. FOR REFERENCE...LA CROSSE NORMALLY
SHOULD HAVE 2.41 INCHES UP THROUGH THE 18TH.
ROCHESTER MN HAS HAD QUITE A BIT MORE RAIN...THUS THE 1.42 INCHES
OBSERVED THROUGH JULY 18TH IS WELL OUTSIDE THE TOP 20 DRIEST.
STILL ROCHESTER IS 1.25 INCHES BELOW NORMAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...NONE.
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ011-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
CLIMATE...AJ