Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/27/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1232 PM MDT TUE SEP 25 2012
.UPDATE...BACKED OFF THE SHOWER POTENTIAL ALONG THE FRONT RANGE
TO A SLIGHT CHANCE THROUGH 21Z...THEN A CHANCE THE REST OF THE
AFTERNOON. WEAK ECHOES HAVE BEEN SLOWLY DEVELOPING ALONG THE FRONT
RANGE EARLY THIS AFTERNOON...AND THIS GRADUAL INCREASING TREND
SHOULD CONTINUE THROUGH THE REST OF THE DAY.
&&
.PREV DISCUSSION... /ISSUED 919 AM MDT TUE SEP 25 2012/
UPDATE...NO BIG CHANGES AT THIS TIME. PCPN MAY BE A BIT SLOER TO
DEVELOP THIS AFTERNOON...BUT NOT ENOUGH TO REFLECT ANY MAJOR
ADJUSTMENTS TO THE FORECAST AT THIS TIME. HRRR BRINGS AN INITIAL
BAND OF PCPN ACROSS SW TO NE ACROSS THE CWFA AFTER 18Z BUT THIS
MAY BE OVERDONE. NEXT BAND PROGGED TO MOVE ACROSS LATE THIS AFTN
AND EVENING.
&&
.AVIATION...DO NOT ANTICIPATE ANY MAJOR CHANGES IN THE UPCOMING
TAFS. MAY NEED TO ADJUST THE TIMING OF THE PCPN THIS AFTN AND
EVENING. ONLY ISSUE MAY INVOLVE THE INCLUSION OF VCTS THIS AFTN.
CAPES THIS AFTN ONLY IN THE 400-500 J/KG RANGE...SO MAY OPT TO GO
WITH JUST RAIN SHOWERS...AND DROP THE MENTION OF VCTS. WEAK SFC
WINDS SHOULD TRANSITION TO ENELY THIS AFTN...SO NO CHANGES THERE.
.PREV DISCUSSION... /ISSUED 312 AM TUE SEP 25 2012/
SHORT TERM...AN UPER LEVEL LOW OVER UTAH WILL MOVE SLOWLY EASTWARD
INTO WRN CO BY THIS EVENING AND THEN REMAIN NEARLY STATIONARY
OVERNIGHT. ALTHOUGH THERE WILL BE ABUNDANT MOISTURE QG FIELDS ARE
WK THRU TONIGHT WITH SOME MINOR UPPER LEVEL DIVERGENCE. AT THIS
TIME WILL KEEP HIGHEST POPS IN THE MTNS AND HIGHER FOOTHILLS WITH
CHC POPS ESLEWHERE. TEMPS WILL BE COLD ENOUGH FOR SOME SNOW OVER
THE HIGHEST PEAKS. ACROSS NERN CO AFTN CAPES ARE FCST TO BE 500
J/KG OR LESS THIS AFTN SO AIRMASS IS ONLY MARGINALLY UNSTABLE WHICH
WILL LIMIT INTENSITY OF TSTMS. AS FOR HIGHS WILL KEEP READINGS IN
THE 70S ACROSS NERN CO WITH THE WARMEST READINGS OVER THE FAR NERN
PLAINS.
FOR TONIGHT AS MENTIONED ABV THE WEAK UPPER LEVEL LOW WILL REMAIN
OVER WRN CO. WILL CONTINUE TO SEE SHOWER ACTIVITY IN THE MTNS
THROUGH MIDNIGHT WITH DECREASIGN ACTIVITY THEREAFTER. OVER THE
PLAINS WILL SEE SCT SHOWERS AND A FEW TSTMS IN THE EARLY EVENING
HOURS WHICH SHOULD GRADUALLY END BY MIDNIGHT.
LONG TERM...MODELS SHOW A WEAKENING UPPER CLOSED LOW/UPPER TROUGH
OVER WESTERN AND NORTHERN COLORADO WEDNESDAY THROUGH THURSDAY. IT
MOVES LITTLE...WITH PRETTY WEAK FLOW ALOFT FOR THE CWA THROUGH
THURSDAY NIGHT. THE SYNOPTIC SCALE ENERGY ACCORDING TO THE QG
VERTICAL VELOCITY FIELDS IS VERY WEAK THROUGH THE PERIODS...UPWARD
INTO THURSDAY MORNING...THEN DOWNWARD. THE BOUNDARY LAYER FLOW HAS
A GENERAL WEAK EASTERLY COMPONENT TO IT ALL FOUR PERIODS. IT IS
MAINLY EAST TO SOUTHEAST OVER THE PLAINS. FOR MOISTURE...BOTH THE
GFS AND NAM SHOW QUITE A BIT WEDNESDAY AND WEDNESDAY NIGHT. THE NAM
CONTINUES THIS TREND INTO THURSDAY...WITH A BIT OF DRYING THURSDAY
NIGHT. THE GFS IS DRIER THAN THE NAM ON THURSDAY AND THURSDAY
NIGHT...BUT THERE IS STILL MOISTURE AROUND. QUITE A BIT MORE THAN
WE HAVE SEEN THE LAST MANY DAYS. PRECIPITABLE WATER VALUES ARE IN
THE 0.60 TO 0.85 INCH RANGE ALL FOUR PERIODS...NOT BAD FOR LATE
SEPTEMBER. THE MODELS HAVE CAPE AROUND BOTH WEDNESDAY AND THURSDAY
..MORE SO ON THE NAM...AND BETTER ON BOTH MODELS FOR THE PLAINS.
THE QPF FIELDS HAVE MEASURABLE PRECIPITATION OVER THE CWA WEDNESDAY
THROUGH THURSDAY NIGHT...THE GFS HAS THE MOST...OF COURSE. THERE IS
GENERALLY MORE PROGGED WEDNESDAY AFTERNOON AND NIGHT. CURRENT GFE
GRIDS HAVE PRETTY DECENT POPS GOING ON WEDNESDAY AND WEDNESDAY NIGHT
..WILL CHANGE LITTLE THERE. MAY UP THURSDAY`S POPS A BIT...
ESPECIALLY ON THE PLAINS DURING THE AFTERNOON AND EVENING. FOR
TEMPERATURES...WEDNESDAY`S HIGHS ARE 2-3 C COOLER THAN TODAY`S.
THURSDAY HIGH`S ARE 0-1 C WARMER THAN WEDNESDAY`S. FOR THE LATER
DAYS...FRIDAY THROUGH MONDAY...MODELS HAVE WEAK FLOW ALOFT FRIDAY
AND SATURDAY. BY SUNDAY AND MONDAY...UPPER RIDGE TO THE WEST AND
NORTH BRINGS NORTHERLY AND NORTHEASTERLY FLOW ALOFT TO THE CWA.
THERE WILL BE SOME MOISTURE AVAILABLE FRIDAY AND SATURDAY...BUT
SUNDAY AND MONDAY DRY OUT. TEMPERATURES LOOK TO BE AROUND SEASONAL
NORMALS.
AVIATION...WILL HAVE QUITE A BIT OF MID LVL CLOUD COVER THROUGH
TONIGHT WITH CEILINGS AROUND 10000 FT. OVERALL INSTABILITY THIS
AFTN INTO THE EARLY EVENING IS NOT THAT GREAT SO WILL JUST MENTION
VCTS AND HAVE A PROB GROUP FOR SHOWERS. CEILINGS AND VISBILITIES
SHOULD STAY ABV MVFR WITH ANY PCPN. WINDS EARLY THIS MORNING ARE
WLY AND ARE FCST TO BECOME LIGHT ENE BY 18Z. FOR TONIGHT WINDS WILL
BECOME MORE WSW BY EARLY EVENING. AT THIS TIME DO NOT EXPECT ANY
STRATUS FOR WED MORNING.
HYDROLOGY...THERE WILL BE A GOOD CHANCE OF SHOWERS AND A FEW
AFTERNOON THUNDERSTORMS HOWEVER RAINFALL RATES SHOULD BE UNDER ONE
QUARTER INCH PER HOUR SO THE THREAT OF FLASH FLOODING SHOULD BE LOW
IN THE BURN AREAS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RJK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
919 AM MDT TUE SEP 25 2012
.UPDATE...NO BIG CHANGES AT THIS TIME. PCPN MAY BE A BIT SLOER TO
DEVELOP THIS AFTERNOON...BUT NOT ENOUGH TO REFLECT ANY MAJOR
ADJUSTMENTS TO THE FORECAST AT THIS TIME. HRRR BRINGS AN INITIAL
BAND OF PCPN ACROSS SW TO NE ACROSS THE CWFA AFTER 18Z BUT THIS
MAY BE OVERDONE. NEXT BAND PROGGED TO MOVE ACROSS LATE THIS AFTN
AND EVENING.
&&
.AVIATION...DO NOT ANTICIPATE ANY MAJOR CHANGES IN THE UPCOMING
TAFS. MAY NEED TO ADJUST THE TIMING OF THE PCPN THIS AFTN AND
EVENING. ONLY ISSUE MAY INVOLVE THE INCLUSION OF VCTS THIS AFTN.
CAPES THIS AFTN ONLY IN THE 400-500 J/KG RANGE...SO MAY OPT TO GO
WITH JUST RAIN SHOWERS...AND DROP THE MENTION OF VCTS. WEAK SFC
WINDS SHOULD TRANSITION TO ENELY THIS AFTN...SO NO CHANGES THERE.
&&
.PREV DISCUSSION... /ISSUED 312 AM TUE SEP 25 2012/
SHORT TERM...AN UPER LEVEL LOW OVER UTAH WILL MOVE SLOWLY EASTWARD
INTO WRN CO BY THIS EVENING AND THEN REMAIN NEARLY STATIONARY
OVERNIGHT. ALTHOUGH THERE WILL BE ABUNDANT MOISTURE QG FIELDS ARE
WK THRU TONIGHT WITH SOME MINOR UPPER LEVEL DIVERGENCE. AT THIS
TIME WILL KEEP HIGHEST POPS IN THE MTNS AND HIGHER FOOTHILLS WITH
CHC POPS ESLEWHERE. TEMPS WILL BE COLD ENOUGH FOR SOME SNOW OVER
THE HIGHEST PEAKS. ACROSS NERN CO AFTN CAPES ARE FCST TO BE 500
J/KG OR LESS THIS AFTN SO AIRMASS IS ONLY MARGINALLY UNSTABLE WHICH
WILL LIMIT INTENSITY OF TSTMS. AS FOR HIGHS WILL KEEP READINGS IN
THE 70S ACROSS NERN CO WITH THE WARMEST READINGS OVER THE FAR NERN
PLAINS.
FOR TONIGHT AS MENTIONED ABV THE WEAK UPPER LEVEL LOW WILL REMAIN
OVER WRN CO. WILL CONTINUE TO SEE SHOWER ACTIVITY IN THE MTNS
THROUGH MIDNIGHT WITH DECREASIGN ACTIVITY THEREAFTER. OVER THE
PLAINS WILL SEE SCT SHOWERS AND A FEW TSTMS IN THE EARLY EVENING
HOURS WHICH SHOULD GRADUALLY END BY MIDNIGHT.
LONG TERM...MODELS SHOW A WEAKENING UPPER CLOSED LOW/UPPER TROUGH
OVER WESTERN AND NORTHERN COLORADO WEDNESDAY THROUGH THURSDAY. IT
MOVES LITTLE...WITH PRETTY WEAK FLOW ALOFT FOR THE CWA THROUGH
THURSDAY NIGHT. THE SYNOPTIC SCALE ENERGY ACCORDING TO THE QG
VERTICAL VELOCITY FIELDS IS VERY WEAK THROUGH THE PERIODS...UPWARD
INTO THURSDAY MORNING...THEN DOWNWARD. THE BOUNDARY LAYER FLOW HAS
A GENERAL WEAK EASTERLY COMPONENT TO IT ALL FOUR PERIODS. IT IS
MAINLY EAST TO SOUTHEAST OVER THE PLAINS. FOR MOISTURE...BOTH THE
GFS AND NAM SHOW QUITE A BIT WEDNESDAY AND WEDNESDAY NIGHT. THE NAM
CONTINUES THIS TREND INTO THURSDAY...WITH A BIT OF DRYING THURSDAY
NIGHT. THE GFS IS DRIER THAN THE NAM ON THURSDAY AND THURSDAY
NIGHT...BUT THERE IS STILL MOISTURE AROUND. QUITE A BIT MORE THAN
WE HAVE SEEN THE LAST MANY DAYS. PRECIPITABLE WATER VALUES ARE IN
THE 0.60 TO 0.85 INCH RANGE ALL FOUR PERIODS...NOT BAD FOR LATE
SEPTEMBER. THE MODELS HAVE CAPE AROUND BOTH WEDNESDAY AND THURSDAY
..MORE SO ON THE NAM...AND BETTER ON BOTH MODELS FOR THE PLAINS.
THE QPF FIELDS HAVE MEASURABLE PRECIPITATION OVER THE CWA WEDNESDAY
THROUGH THURSDAY NIGHT...THE GFS HAS THE MOST...OF COURSE. THERE IS
GENERALLY MORE PROGGED WEDNESDAY AFTERNOON AND NIGHT. CURRENT GFE
GRIDS HAVE PRETTY DECENT POPS GOING ON WEDNESDAY AND WEDNESDAY NIGHT
..WILL CHANGE LITTLE THERE. MAY UP THURSDAY`S POPS A BIT...
ESPECIALLY ON THE PLAINS DURING THE AFTERNOON AND EVENING. FOR
TEMPERATURES...WEDNESDAY`S HIGHS ARE 2-3 C COOLER THAN TODAY`S.
THURSDAY HIGH`S ARE 0-1 C WARMER THAN WEDNESDAY`S. FOR THE LATER
DAYS...FRIDAY THROUGH MONDAY...MODELS HAVE WEAK FLOW ALOFT FRIDAY
AND SATURDAY. BY SUNDAY AND MONDAY...UPPER RIDGE TO THE WEST AND
NORTH BRINGS NORTHERLY AND NORTHEASTERLY FLOW ALOFT TO THE CWA.
THERE WILL BE SOME MOISTURE AVAILABLE FRIDAY AND SATURDAY...BUT
SUNDAY AND MONDAY DRY OUT. TEMPERATURES LOOK TO BE AROUND SEASONAL
NORMALS.
AVIATION...WILL HAVE QUITE A BIT OF MID LVL CLOUD COVER THROUGH
TONIGHT WITH CEILINGS AROUND 10000 FT. OVERALL INSTABILITY THIS
AFTN INTO THE EARLY EVENING IS NOT THAT GREAT SO WILL JUST MENTION
VCTS AND HAVE A PROB GROUP FOR SHOWERS. CEILINGS AND VISBILITIES
SHOULD STAY ABV MVFR WITH ANY PCPN. WINDS EARLY THIS MORNING ARE
WLY AND ARE FCST TO BECOME LIGHT ENE BY 18Z. FOR TONIGHT WINDS WILL
BECOME MORE WSW BY EARLY EVENING. AT THIS TIME DO NOT EXPECT ANY
STRATUS FOR WED MORNING.
HYDROLOGY...THERE WILL BE A GOOD CHANCE OF SHOWERS AND A FEW
AFTERNOON THUNDERSTORMS HOWEVER RAINFALL RATES SHOULD BE UNDER ONE
QUARTER INCH PER HOUR SO THE THREAT OF FLASH FLOODING SHOULD BE LOW
IN THE BURN AREAS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RJK
AVIATION...COOPER
AREA FORECAST DISCUSSION...UPDATED
NWS MELBOURNE FL
645 AM EDT TUE SEP 25 2012
.DISCUSSION...
UPDATE...DYNAMIC LIFT OVER THE COASTAL WATERS N OF THE CAPE IS BEING
ENHANCED BY A THIN MID LVL VORT BAND LYING N OF THE I-4 CORRIDOR.
H30-H20 DIVERGENCE FIELDS HAVE SHOWN A NOTABLE INCREASE OVER THE
PAST FEW HRS...AS HAS THE RADAR TRENDS. NLDN AND LDAR ARE EVEN
PICKING UP AN OCNL LTG STRIKE. AS SUCH...WILL UPDATE ZONES TO
REFLECT HIGHER SHRA/TSRA CHANCES OVER THE NRN HALF OF THE CWA.
TODAY-TONIGHT...
A LARGE HI PRES RIDGE SPANNING THE ERN SEABOARD AND THE DEEP SOUTH
WILL PUSH INTO THE W ATLC TODAY...GENERATING A DEEP AND STEADY E/NE
FLOW ACRS CENTRAL FL. LATEST RAP ANALYSIS SHOWS A TONGUE OF DRY AIR
LINGERING OVER THE CENTRAL PENINSULA S OF THE I-4 CORRIDOR...BUT
WITH DEEPER MOISTURE PUSHING DOWN THE ERN PANHANDLE PENINSULA. RADAR
OBS CONFIRM THIS WITH THIN BUT PERSISTENT SHRA BANDS OFF THE VOLUSIA
CO COAST. DEEPER MOISTURE ALSO NOTED OVER MUCH OF THE BAHAMA BANK.
H85-H50 LAPSE RATES BTWN 5.5-6.0C/KM INDICATE SOME DEGREE OF
INSTABILITY...BUT WITH H85-H70 RATES BLO 5.0C/KM..IT WILL BE
DIFFICULT TO INITIALIZE DEEP VERTICAL MOTION.
AS THE RIDGE EXPANDS EWD...LOW/MID LVL WINDS WILL SHIFT MORE TO THE
E...SHUNTING MOISTURE INTO WHAT REMAINS OF THE DRY AIR SLOT.
ALOFT...A MID/UPR LVL RIDGE AXIS OVER THE FL STRAITS WILL PUSH A
BAND OF MID LVL VORTICITY BAND OUT OF S FL AND ACRS LAKE OKEECHOBEE.
A DEPARTING H30-H20 JET STREAK OFF THE CAROLINA COAST WILL CONTINUE
TO DRAG CONSIDERABLE HIGH CLOUDS ACRS THE PENINSULA AS WELL.
DESPITE THE INCREASING MID LVL VORTICITY...OVERALL INSTABILITY WILL
BE LIMITED. THE COMBINED EFFECTS OF THE LINGERING DRY AIR...DENSE
UPR CLOUD DECK LIMITING INSOLATION...AND VERY WEAK H85-H70 LAPSE
RATES WILL BE TOO MUCH TO GENERATE TSRAS. THROW IN THE DEEPENING
ONSHORE FLOW THAT WILL CREATE A DIFFUSE EAST COAST SEA BREEZE WITH
WEAK SFC/LOW LVL FORCING...AND THUNDER CHANCES BECOME TOO LOW TO
MENTION. WILL GO WITH ISOLD COASTAL SHRAS THRU EARLY AFTN...
AREAWIDE THRU EARLY EVNG...THEN BACK TO COASTAL THRU TONIGHT.
ONSHORE FLOW AND CONSIDERABLE UPR LVL CLOUDS WILL KEEP MAX TEMPS
NEAR AVG (M80S)...MIN TEMPS ABV AVG (L70S).
WED-THU...
SURFACE HIGH PRESSURE RIDGE NORTH OF THE AREA WILL PROVIDE AN
EASTERLY WIND FLOW. THE LATEST GFS RUN SHOWS OLD FRONTAL BAND
MOISTURE LIFTING BACK INTO THE AREA WED SO HAVE MAINTAINED CHANCE
POPS (30 PERCENT COAST AND 40 PERCENT INLAND). THE GFS SHOWS AN
UPPER LEVEL SHORTWAVE TROUGH APPROACHING THU SO HAVE GONE WITH 40
POPS AREAWIDE.
FRI-TUE...
UPPER LEVEL SHORTWAVE TROUGH SHOULD SHIFT EAST OF THE AREA ON FRI
AND DECREASE POPS. THE GFS INDICATES LOWER POPS SO HAVE GONE WITH
30 PERCENT AREAWIDE.
WEEKEND-EARLY NEXT WEEK..THE MODELS GENERALLY AGREE ON A MORE
SUBSTANTIAL TROUGH ORGANIZING OVER THE EASTERN PART OF THE
COUNTRY. THERE ARE SOME TIMING AND STRENGTH DIFFERENCES BETWEEN
THE GFS AND ECMWF. THE GFS IS STRONGER...THOUGH THE 00Z ECMWF HAS
TRENDED DEEPER FROM ITS 12Z RUN.
WILL STAY WITH 30-40 POPS THROUGH THE PERIOD...HOWEVER THE SUN-TUE
PERIOD MAY HAVE GREATER CHANCES. WILL WAIT A LITTLE LONGER TO GO
HIGHER THOUGH AS WE DO NOT WANT TO DIFFER TOO MUCH FROM CLIMO THAT
FAR OUT IN THE FORECAST.
&&
.AVIATION...
ALL SITES VFR WITH PREVAILING CIGS AOA FL120 UNLESS OTHERWISE NOTED:
THRU 25/12Z...BRIEF MVFR VSBYS/CIGS IN ISOLD SHRAS N OF KTIX. BTWN
25/12Z-25/24Z...SLGT CHC MVFR SHRAS COASTAL SITES...AFT 25/18Z SLGT
CHC IFR TSRAS INTERIOR SITES...OCNL SFC WND G20KTS COASTAL SITES.
AFT 26/00Z...SLGT CHC MVFR SHRAS COASTAL SITES.
&&
.MARINE...
TODAY-TONIGHT...
HI PRES RIDGE AXIS EXTENDING FROM THE CANADIAN MARITIMES...ACRS THE
NC OUTER BANKS...O THE RIO GRANDE VALLEY WILL GENERATE A GENTLE TO
MODERATE E/NE BREEZE ACRS THE LCL ATLC. EARLY AM OBS FROM THE DATA
BUOYS SHOW THE SWELL THAT HAS BEEN ANTICIPATED FOR THE PAST FEW DAYS
HAS BEGUN IMPACTING THE WATERS WELL OFFSHORE. BOUY010/012 BOTH HAVE
MEASURED +6FT SEAS SINCE MIDNIGHT WITH A 4-5FT SWELL COMPONENT.
BUOY009 STILL HOLDING BTWN 3-4FT...BUT THIS WILL CHANGE NOTICEABLY
BY DAYBREAK AS SWELL TRAIN ADVANCES WESTWARD.
INITIALLY SEAS MAY BUILD UP TO 7FT IN THE GULF STREAM BUT WILL FALL
BACK TO ARND 6FT BY AFTN AS THE LEADING EDGE OF THE SWELL DAMPENS
OUT ON THE E FL COAST. THIS WINDOW IS TOO NARROW TO WARRANT AN SCA
WITH THE MORNING PACKAGE. HOWEVER... A CAUTIONARY STATEMENT FOR THE
OFFSHORE LEG N OF SEBASTIAN INLET IS PRUDENT AS A SLIGHTLY TIGHTER
PGRAD WILL SUPPORT SFC/BNDRY LYR WNDS ARND 15KTS WITH OCNL GUSTS
OVER 20KTS.
WED-THU...
HIGH PRESSURE RIDGE NORTH OF THE WATERS WILL MAINTAIN AN EASTERLY
WIND FLOW. THE LATEST MARINE MOS INDICATES SPEEDS ABOUT 10-13 KNOTS.
HIGHER MOISTURE IS FORECAST TO RETURN SO THE CHANCE FOR
SHOWERS/STORMS WILL BE INCREASING.
FRI-SAT...
THE HIGH PRESSURE RIDGE IS FORECAST TO WEAKEN. THE LATEST GFS
INDICATES WINDS 5-10 KNOTS MOSTLY FROM THE EAST. RAIN CHANCES MIGHT
SLIGHTLY DECREASE FROM THE WED-THU VALUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 85 71 87 75 / 20 20 30 20
MCO 86 72 90 73 / 20 10 40 20
MLB 87 73 87 77 / 20 20 30 20
VRB 86 73 88 75 / 20 20 30 20
LEE 87 70 90 73 / 20 10 40 20
SFB 86 72 89 74 / 20 10 40 20
ORL 86 72 90 75 / 20 10 40 20
FPR 86 73 87 75 / 20 20 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION...UPDATED
NWS MELBOURNE FL
345 AM EDT TUE SEP 25 2012
.DISCUSSION...
TODAY-TONIGHT...
A LARGE HI PRES RIDGE SPANNING THE ERN SEABOARD AND THE DEEP SOUTH
WILL PUSH INTO THE W ATLC TODAY...GENERATING A DEEP AND STEADY E/NE
FLOW ACRS CENTRAL FL. LATEST RAP ANALYSIS SHOWS A TONGUE OF DRY AIR
LINGERING OVER THE CENTRAL PENINSULA S OF THE I-4 CORRIDOR...BUT
WITH DEEPER MOISTURE PUSHING DOWN THE ERN PANHANDLE PENINSULA. RADAR
OBS CONFIRM THIS WITH THIN BUT PERSISTENT SHRA BANDS OFF THE VOLUSIA
CO COAST. DEEPER MOISTURE ALSO NOTED OVER MUCH OF THE BAHAMA BANK.
H85-H50 LAPSE RATES BTWN 5.5-6.0C/KM INDICATE SOME DEGREE OF
INSTABILITY...BUT WITH H85-H70 RATES BLO 5.0C/KM..IT WILL BE
DIFFICULT TO INITIALIZE DEEP VERTICAL MOTION.
AS THE RIDGE EXPANDS EWD...LOW/MID LVL WINDS WILL SHIFT MORE TO THE
E...SHUNTING MOISTURE INTO WHAT REMAINS OF THE DRY AIR SLOT.
ALOFT...A MID/UPR LVL RIDGE AXIS OVER THE FL STRAITS WILL PUSH A
BAND OF MID LVL VORTICITY BAND OUT OF S FL AND ACRS LAKE OKEECHOBEE.
A DEPARTING H30-H20 JET STREAK OFF THE CAROLINA COAST WILL CONTINUE
TO DRAG CONSIDERABLE HIGH CLOUDS ACRS THE PENINSULA AS WELL.
DESPITE THE INCREASING MID LVL VORTICITY...OVERALL INSTABILITY WILL
BE LIMITED. THE COMBINED EFFECTS OF THE LINGERING DRY AIR...DENSE
UPR CLOUD DECK LIMITING INSOLATION...AND VERY WEAK H85-H70 LAPSE
RATES WILL BE TOO MUCH TO GENERATE TSRAS. THROW IN THE DEEPENING
ONSHORE FLOW THAT WILL CREATE A DIFFUSE EAST COAST SEA BREEZE WITH
WEAK SFC/LOW LVL FORCING...AND THUNDER CHANCES BECOME TOO LOW TO
MENTION. WILL GO WITH ISOLD COASTAL SHRAS THRU EARLY AFTN...
AREAWIDE THRU EARLY EVNG...THEN BACK TO COASTAL THRU TONIGHT.
ONSHORE FLOW AND CONSIDERABLE UPR LVL CLOUDS WILL KEEP MAX TEMPS
NEAR AVG (M80S)...MIN TEMPS ABV AVG (L70S).
WED-THU...
SURFACE HIGH PRESSURE RIDGE NORTH OF THE AREA WILL PROVIDE AN
EASTERLY WIND FLOW. THE LATEST GFS RUN SHOWS OLD FRONTAL BAND
MOISTURE LIFTING BACK INTO THE AREA WED SO HAVE MAINTAINED CHANCE
POPS (30 PERCENT COAST AND 40 PERCENT INLAND). THE GFS SHOWS AN
UPPER LEVEL SHORTWAVE TROUGH APPROACHING THU SO HAVE GONE WITH 40
POPS AREAWIDE.
FRI-TUE...
UPPER LEVEL SHORTWAVE TROUGH SHOULD SHIFT EAST OF THE AREA ON FRI
AND DECREASE POPS. THE GFS INDICATES LOWER POPS SO HAVE GONE WITH
30 PERCENT AREAWIDE.
WEEKEND-EARLY NEXT WEEK..THE MODELS GENERALLY AGREE ON A MORE
SUBSTANTIAL TROUGH ORGANIZING OVER THE EASTERN PART OF THE
COUNTRY. THERE ARE SOME TIMING AND STRENGTH DIFFERENCES BETWEEN
THE GFS AND ECMWF. THE GFS IS STRONGER...THOUGH THE 00Z ECMWF HAS
TRENDED DEEPER FROM ITS 12Z RUN.
WILL STAY WITH 30-40 POPS THROUGH THE PERIOD...HOWEVER THE SUN-TUE
PERIOD MAY HAVE GREATER CHANCES. WILL WAIT A LITTLE LONGER TO GO
HIGHER THOUGH AS WE DO NOT WANT TO DIFFER TOO MUCH FROM CLIMO THAT
FAR OUT IN THE FORECAST.
&&
.AVIATION...
ALL SITES VFR WITH PREVAILING CIGS AOA FL120 UNLESS OTHERWISE NOTED:
THRU 25/12Z...BRIEF MVFR VSBYS/CIGS IN ISOLD SHRAS N OF KTIX. BTWN
25/12Z-25/24Z...SLGT CHC MVFR SHRAS COASTAL SITES...AFT 25/18Z SLGT
CHC IFR TSRAS INTERIOR SITES...OCNL SFC WND G20KTS COASTAL SITES.
AFT 26/00Z...SLGT CHC MVFR SHRAS COASTAL SITES.
&&
.MARINE...
TODAY-TONIGHT...
HI PRES RIDGE AXIS EXTENDING FROM THE CANADIAN MARITIMES...ACRS THE
NC OUTER BANKS...O THE RIO GRANDE VALLEY WILL GENERATE A GENTLE TO
MODERATE E/NE BREEZE ACRS THE LCL ATLC. EARLY AM OBS FROM THE DATA
BUOYS SHOW THE SWELL THAT HAS BEEN ANTICIPATED FOR THE PAST FEW DAYS
HAS BEGUN IMPACTING THE WATERS WELL OFFSHORE. BOUY010/012 BOTH HAVE
MEASURED +6FT SEAS SINCE MIDNIGHT WITH A 4-5FT SWELL COMPONENT.
BUOY009 STILL HOLDING BTWN 3-4FT...BUT THIS WILL CHANGE NOTICEABLY
BY DAYBREAK AS SWELL TRAIN ADVANCES WESTWARD.
INITIALLY SEAS MAY BUILD UP TO 7FT IN THE GULF STREAM BUT WILL FALL
BACK TO ARND 6FT BY AFTN AS THE LEADING EDGE OF THE SWELL DAMPENS
OUT ON THE E FL COAST. THIS WINDOW IS TOO NARROW TO WARRANT AN SCA
WITH THE MORNING PACKAGE. HOWEVER... A CAUTIONARY STATEMENT FOR THE
OFFSHORE LEG N OF SEBASTIAN INLET IS PRUDENT AS A SLIGHTLY TIGHTER
PGRAD WILL SUPPORT SFC/BNDRY LYR WNDS ARND 15KTS WITH OCNL GUSTS
OVER 20KTS.
WED-THU...
HIGH PRESSURE RIDGE NORTH OF THE WATERS WILL MAINTAIN AN EASTERLY
WIND FLOW. THE LATEST MARINE MOS INDICATES SPEEDS ABOUT 10-13 KNOTS.
HIGHER MOISTURE IS FORECAST TO RETURN SO THE CHANCE FOR
SHOWERS/STORMS WILL BE INCREASING.
FRI-SAT...
THE HIGH PRESSURE RIDGE IS FORECAST TO WEAKEN. THE LATEST GFS
INDICATES WINDS 5-10 KNOTS MOSTLY FROM THE EAST. RAIN CHANCES MIGHT
SLIGHTLY DECREASE FROM THE WED-THU VALUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 85 71 87 75 / 20 20 30 20
MCO 86 72 90 73 / 20 10 40 20
MLB 87 73 87 77 / 20 20 30 20
VRB 86 73 88 75 / 20 20 30 20
LEE 87 70 90 73 / 20 10 40 20
SFB 86 72 89 74 / 20 10 40 20
ORL 86 72 90 75 / 20 10 40 20
FPR 86 73 87 75 / 20 20 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
320 AM EDT TUE SEP 25 2012
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A SOMEWHAT FLATTER UPPER
LEVEL PATTERN COMPARED TO 24 HOURS AGO AS THE LONGWAVE TROUGH OVER
THE EASTERN CONUS DE-AMPLIFIES. THE MID-LEVEL FLOW LEFT BEHIND
ACROSS THE SOUTHEASTERN STATES HAS TAKEN ON A MORE ZONAL PATTERN.
ONE OTHER FEATURE OF NOTE IS A UPPER LOW SPINNING NEAR THE 4-CORNERS
REGION THIS MORNING. THIS ENERGY IS FORECAST TO SLOWLY SHEAR OUT AS
IT PUSHES EASTWARD THE NEXT FEW DAYS WITH LITTLE TO NO IMPACT ON OUR
LOCAL WEATHER. IN THE UPPER LEVELS...SOUTHERN STREAM FLOW CONTINUES
TO BRING AMPLE MOISTURE NORTHWARD OVER THE EASTERN GULF AND FL
PENINSULA. THIS JET ENERGY WILL KEEP THE HIGH LEVEL CIRRUS A PART OF
THE FORECAST THROUGH THE DAY...ESPECIALLY OVER CENTRAL AND SOUTHERN
PORTIONS OF THE PENINSULA. 00Z KTBW SOUNDING SHOWS THIS MOISTURE
ABOVE 400MB...OVERTOP A STILL VERY DRY COLUMN THROUGH THE MIDDLE AND
LOWER PORTIONS OF THE TROPOSPHERE. THIS MAJORITY DRY COLUMN IS
RESULTING IN A PW VALUE ON THAT SOUNDING OF ONLY AROUND 0.8"...WHICH
IS AROUND 1/2 OF CLIMO FOR LATE SEPTEMBER.
AT THE SURFACE...OLD FRONTAL BOUNDARY CONTINUES TO DECAY/WASH OUT
OVER THE SOUTHERN FL PENINSULA THIS MORNING WITH OUR LOCAL GRADIENT
BECOME MORE AND MORE DOMINATED BY THE 1024MB HIGH PRESSURE RIDGE TO
OUR NORTH. A GENERAL NE/E FLOW AT THE SURFACE AROUND THIS RIDGE WILL
BRING A RETURN OF ATLANTIC MOISTURE AND HUMID CONDITIONS TO THE
REGION THROUGH THE MIDDLE OF THE WEEK.
&&
.SHORT TERM (TODAY THROUGH THURSDAY)...
TODAY/TONIGHT...THE STRENGTH OF THE MID-LEVEL DRY AIR SHOULD HOLD
TODAY OVER CENTRAL AND NORTHERN ZONES KEEPING THE FORECAST GENERALLY
DRY. AN ISOLATED LOW TOPPED SPEED CONVERGENCE SHOWER OR 2 DURING THE
AFTERNOON IS POSSIBLE UP TOWARD SUMTER COUNTY IF ANY CAN SURVIVE THE
TREK INLAND FROM THE EAST COAST. THESE WILL BE VERY FEW AND FAR
BETWEEN THOUGH. THE FURTHER SOUTH ONE TRAVELS FROM THE I-4
CORRIDOR...AND THE FASTER THE DRY AIR WILL ERODE AND HENCE BETTER
CHANCES FOR A FEW AFTERNOON SHOWERS. NWP GUIDANCE OFTEN HAS A BIT OF
A FAST BIAS TOWARD THE EROSION OF THESE DRY LAYERS AND WILL ONLY ADD
A SLIGHT CHANCE POP FOR NOW. AS MENTIONED IN THE SYNOPSIS...THE
FORECAST WILL FEATURE OF MIX OF SUN AND CLOUDS...ALTHOUGH THE HIGH
LEVEL CIRRUS MAY WIN OUT AT TIMES OVER THE CENTRAL AND SOUTHERN
ZONES. REGARDLESS...SHOULD STILL SEE ENOUGH INSOLATION TO ALLOW
AFTERNOON TEMPS TO CREEP UP TO WITHIN A DEGREE OR 2 OF 90.
ANY ISOLATED SHOWERS SHOULD DISSIPATE QUICKLY WITH SUNSET SETTING UP
A GENERALLY DRY OVERNIGHT PERIOD FOR LAND ZONES. THE INCREASING LOW
LEVEL MOISTURE WILL SLOW THE TEMPERATURE DROP AND WILL CERTAINLY SEE
LESS LOCATIONS REACHING THE MIDDLE AND UPPER 60S COMPARED TO THIS
MORNING. BEST CHANCES TO DROP BELOW 70 WILL BE UP OVER THE NATURE
COAST ZONES...AND ALSO THE NORMALLY COOLER SPOTS OF DE SOTO...HARDEE
AND HIGHLANDS COUNTIES.
WEDNESDAY/THURSDAY...EASTERLY LOW LEVEL FLOW WILL CONTINUE AROUND
HIGH PRESSURE PARKED OVER THE CAROLINAS. GFS/NAM/ECMWF ALL SHOW THAT
MUCH OF THE MID-LEVEL DRY AIR WILL HAVE BEEN ERODED BY THIS PERIOD
ALLOWING FOR A MUCH LESS HOSTILE COLUMN FOR CONVECTION. WILL BRING
MORE NORMAL SCT SHOWER/STORMS CHANCES BACK TO THE FORECAST (30-40%)
FOR BOTH WEDNESDAY AND THURSDAY AFTERNOONS. OVERNIGHT LOWS WILL
CONTINUE TO MODERATE A FEW DEGREES EACH DAY WITH DAYTIME HIGHS
REMAINING IN THE UPPER 80S TO LOWER 90S.
&&
.LONG TERM (FRIDAY THROUGH NEXT MONDAY)...
A RATHER COMPLEX SYNOPTIC PATTERN WILL BE SETTING UP OVER NORTH
AMERICA DURING THE EXTENDED PORTION OF THE FORECAST...BUT THE
IMPACTS TO OUR AREA WILL LIKELY BE BEYOND DAY SEVEN.
THE 00Z GFS...12Z ECMWF AND 00Z CANADIAN ALL START THE EXTENDED
PERIOD WITH AN UPPER-LEVEL AREA OF HIGH PRESSURE OVER THE WESTERN
GULF WITH A RIDGE EXTENDING EASTWARD ACROSS THE NORTHERN GULF. THE
GFS SHOWS A POTENT SHORT WAVE TROUGH DIGGING SOUTHEASTWARD TOWARD
THE GREAT LAKES ON FRIDAY THEN TURNING EASTWARD AND MOVING ACROSS
SOUTHERN CANADA AND TOWARD THE CANADIAN MARITIMES OVER THE WEEKEND.
THE ECMWF AND CANADIAN BOTH START WITH THE SHORT WAVE ENERGY
DROPPING TOWARD THE GREAT LAKES ON FRIDAY BUT THEN SHOW NO REAL
EASTWARD MOVEMENT THROUGH AT LEAST SUNDAY. THE ECMWF THEN LIFTS THE
TROUGH NORTHEASTWARD NEAR OR NORTH OF NEW ENGLAND SUNDAY NIGHT AND
MONDAY. THE GFS SOLUTION IS MORE PROGRESSIVE BUT ALLOWS A PIECE OF
THE ENERGY TO STAY BEHIND RESULTING IN A CUT-OFF LOW OVER THE MIDDLE
MISSISSIPPI VALLEY SUNDAY AND MONDAY. THE SLOWER ECMWF KEEPS A
BROADER TROUGH IN PLACE OVER THE EASTERN HALF OF THE COUNTRY WHICH
RESULTS IN A MUCH WEAKER CUT-OFF LOW THAT IS ALSO MORE PROGRESSIVE.
AS MENTIONED EARLIER... REGARDLESS OF WHICH SCENARIO UNFOLDS...ANY
SIGNIFICANT IMPACTS OF THIS SYSTEM WILL BE BEYOND THIS FORECAST
PERIOD...WITH A POTENTIAL FRONTAL PASSAGE AROUND THE MIDDLE OF NEXT
WEEK.
IN THE MEAN TIME...WILL BASE THE FORECAST ON THE ECMWF WHICH IS
SUPPORTED BY THE CANADIAN MODEL. WE WILL BE DEALING WITH A
SUMMER-LIKE PATTERN FRIDAY THROUGH MONDAY. WEAK SURFACE RIDGING
NORTH OF THE REGION ON FRIDAY WILL SETTLE SOUTHWARD TOWARD FLORIDA
FOR SATURDAY THROUGH MONDAY. WITH AMPLE MOISTURE IN PLACE...EXPECT
AFTERNOON SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG GULF AND BAY
BREEZE BOUNDARIES EACH DAY.
&&
.AVIATION...
VFR NEXT 24 HOURS. SOME PATCHY FOG IS POSSIBLE MAINLY AROUND PGD AND
LAL TOWARD SUNRISE. A FEW SHOWERS COULD DEVELOP LATE IN THE
AFTERNOON FROM PGD SOUTH TO RSW AND FMY...BUT OVERALL COVERAGE WILL
BE TOO LOW FOR MENTION IN TAFS AT THIS TIME.
&&
.MARINE...
NORTHEAST TO EAST FLOW AROUND HIGH PRESSURE CENTERED NEAR THE
CAROLINAS WILL CONTINUE THROUGH THE NEXT SEVERAL DAYS. THE HIGH
POSITION TO OUR NORTH AND NORTHEAST IS FAVORABLE TO SUPPORT
OVERNIGHT SURGES WITHIN THE EASTERLY FLOW. WINDS APPROACHING
CAUTIONARY LEVELS ARE POSSIBLE BOTH TONIGHT AND WEDNESDAY
NIGHT...ESPECIALLY ALONG AND OFFSHORE OF THE NATURE COAST. THE
RIDGE OVER THE CAROLINAS WILL WEAKEN DURING THE LATER PORTION OF
THE WEEK ALLOWING WINDS TO BECOME MORE LIGHT AND VARIABLE BY THE
WEEKEND.
&&
.FIRE WEATHER...
INCREASING LOW LEVEL ATLANTIC MOISTURE ARRIVING ON NORTHEAST TO
EAST FLOW WILL HELP KEEP RELATIVE HUMIDITY VALUES ABOVE CRITICAL
LEVELS THROUGH THE MIDDLE OF THE WEEK. THIS INCREASE IN MOISTURE
ALONG WITH BETTER CHANCES FOR SHOWERS AND STORMS WEDNESDAY AND
THURSDAY WILL FURTHER PREVENT CRITICAL FIRE WEATHER CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 73 89 74 / 10 10 40 20
FMY 89 73 90 73 / 20 20 40 20
GIF 90 71 90 72 / 10 10 40 20
SRQ 88 72 88 73 / 10 10 40 20
BKV 90 68 90 69 / 10 10 40 20
SPG 88 76 88 77 / 10 10 40 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
859 PM CDT WED SEP 26 2012
.DISCUSSION...
ISSUED 859 PM CDT WED SEP 26 2012
NEARLY STATIONARY FRONTAL BOUNDARY STILL BISECTING THE FORECAST
AREA THIS EVENING...ALTHOUGH THE BULK OF THE PRECIPITATION FALLING
IS WELL SOUTH OF THE BOUNDARY. DO NOT EXPECT SIGNIFICANT RAINFALL
FOR THE REST OF THE NIGHT...BUT CAN NOT DISCOUNT THE RISK FOR SOME
REDEVELOPMENT AS A VIGOROUS WAVE CURRENTLY CROSSING MISSOURI
INTERACTS WITH THE FRONT. THE PRESENCE OF THE FRONT...LIGHT WINDS
IN ITS VICINITY...AND GRADUALLY CLEARING SKIES FROM THE NORTH POSE
A FOG THREAT TONIGHT. HOWEVER...THE FOG THREAT SHOULD BE FURTHER
SOUTH TONIGHT THAN IT WAS LAST NIGHT...MOST LIKELY CLOSER TO I-70
CORRIDOR WHERE MORE SIGNIFICANT RAINS HAVE FALLEN LATELY AND
SURFACE DEW POINTS WILL BE LAST TO START DROPPING.
GOING FORECAST IS IN GOOD SHAPE OVERALL. MAIN CHANGE PLANNED IS TO
REDUCE POP AND THUNDER MENTION OVERNIGHT. OTHERWISE...MINOR
CHANGES ARE PLANNED FOR THE LATEST TRENDS.
BAK
&&
.AVIATION...
ISSUED 659 PM CDT WED SEP 26 2012
LIGHT/VARIABLE WINDS SHOULD CONTINUE TO TREND NORTHEAST TO NORTH
THROUGH THE PERIOD AS HIGH PRESSURE BEGINS TO BUILD INTO THE AREA
BEHIND A DEPARTING FRONTAL BOUNDARY. THE DEPARTURE OF THIS FRONT
WILL ALSO RESULT IN A GRADUAL CLEARING OF THE SKIES FROM NORTH TO
SOUTH. THERE IS STILL A THREAT FOR FOG TO DEVELOP LATER TONIGHT AS
THE SKIES CLEAR...BUT CONFIDENCE NOT HIGH THAT WIDESPREAD FOG WILL
DEVELOP DUE TO DRIER AIR FILTERING INTO THE AREA BEHIND THE FRONT.
SO...WILL NOT INCLUDE FOG AT THIS TIME.
BAK
&&
.PREV DISCUSSION...
ISSUED 221 PM CDT WED SEP 26 2012
RAIN CHANCES WILL PERSIST ACROSS SOUTH-CENTRAL ILLINOIS THROUGH
THURSDAY NIGHT...BEFORE A LONG STRETCH OF DRY WEATHER DEVELOPS
ACROSS THE ENTIRE REGION THROUGH NEXT WEEK.
SHORT TERM...TONIGHT THROUGH SATURDAY
19Z/2PM SURFACE ANALYSIS SHOWS A SLOW-MOVING COLD FRONT EXTENDING
FROM JUST SOUTH OF KIKK TO NEAR KUIN. TO THE NORTH OF THE
FRONT...WINDS HAVE BECOME NORTHERLY AND A DRIER AIRMASS IS
BEGINNING TO SETTLE INTO THE FAR NORTHERN KILX CWA. MEANWHILE
SOUTH OF THE BOUNDARY...A MOIST ENVIRONMENT CHARACTERIZED BY
DEWPOINTS IN THE 60S IS SUPPORTING SCATTERED SHOWERS/THUNDER
ACROSS THE REMAINDER OF THE AREA. COLD FRONT IS NOT EXPECTED TO
DROP MUCH FURTHER SOUTH TONIGHT...AS UPPER-LEVEL WAVE CURRENTLY
OVER EASTERN KANSAS WILL IMPEDE ITS SOUTHERN PROGRESS. AS A
RESULT...THINK FRONT WILL ONLY SINK TO JUST SOUTH OF THE I-72
CORRIDOR OVERNIGHT. AS A RESULT...WILL CONTINUE TO CARRY LOW
CHANCE POPS ACROSS THE CENTRAL ZONES...WITH HIGHEST POPS FOCUSED
ALONG/SOUTH OF I-70 WHERE DEEPEST MOISTURE AND STRONGEST LIFT WILL
BE PRESENT. WITH FRONT IN THE VICINITY AND DRIER AIRMASS ONLY
TRICKLING SLOWLY SOUTHWARD...THINK AREAS OF FOG WILL DEVELOP
OVERNIGHT. LAST NIGHT...FOG FORMED IN LOCATIONS NEAR/SOUTH OF THE
BOUNDARY WHERE DEWPOINTS HOVERED IN THE UPPER 50S/LOWER 60S. THOSE
CONDITIONS WILL LIKELY EXIST FURTHER SOUTH TONIGHT...PRIMARILY
ALONG/SOUTH OF I-70. NAM FORECAST SOUNDINGS PROVIDE A STRONG
SIGNAL FOR FOG AT BOTH KMTO AND KLWV AND HRRR VISBY PROGS SUPPORT
THIS AS WELL...SO HAVE INCLUDED AREAS OF FOG ACROSS THE SOUTHEAST
AFTER MIDNIGHT.
ANY FOG WILL GRADUALLY BURN OFF THURSDAY MORNING...HOWEVER SKIES
WILL REMAIN MOSTLY CLOUDY THROUGHOUT THE DAY ACROSS THE SOUTHEAST
AS THE FRONT MAKES ONLY VERY SLOW PROGRESS SOUTHWARD. WILL
CONTINUE WITH CHANCE POPS ALONG AND SOUTH OF A PARIS TO
SHELBYVILLE LINE...WITH DRY CONDITIONS EXPECTED FURTHER NORTH.
BOTH THE NAM AND GFS FINALLY GIVE THE BOUNDARY A GOOD PUSH
SOUTHWARD BY FRIDAY...AS HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. WILL HOLD ON TO A SLIM CHANCE FOR A SHOWER SOUTH OF I-70
INTO FRIDAY IN CASE FRONT IS DELAYED...BUT WILL GO WITH MOSTLY
SUNNY AND DRY CONDITIONS ELSEWHERE.
WITH HIGH PRESSURE BEING THE DOMINANT WEATHER FEATURE...SUNNY
SKIES AND DRY WEATHER IS EXPECTED THIS WEEKEND. TEMPERATURES WILL
REMAIN NEAR NORMAL FOR THIS TIME OF YEAR...WITH DAYTIME HIGHS IN
THE LOWER TO MIDDLE 70S AND OVERNIGHT LOWS IN THE LOWER 50S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
A VIGOROUS SHORT-WAVE WILL DIVE INTO THE GREAT LAKES LATE IN THE
WEEKEND...PUSHING A WEAK COLD FRONT/SURFACE TROUGH THROUGH CENTRAL
ILLINOIS SATURDAY NIGHT INTO SUNDAY. SYSTEM WILL HAVE VERY LITTLE
MOISTURE TO WORK WITH...SO AM ONLY EXPECTING A FEW CLOUDS AS IT
PASSES THROUGH. AFTER THAT...A MAJOR PATTERN CHANGE IS IN STORE
NEXT WEEK. BOTH THE GFS AND ECMWF ARE SHOWING AN UPPER-LEVEL RIDGE
BUILDING ACROSS THE PLAINS INTO THE MIDWEST BY THE MIDDLE AND END
OF THE WEEK. RISING HEIGHTS AND INCREASING SOUTHERLY FLOW WILL
BOOST TEMPS WELL INTO THE 70S BY MONDAY AND TUESDAY...THEN PERHAPS
INTO THE 80S AFTER THAT. BOTH MODELS INDICATE 850MB TEMPS IN THE
15 TO 17C RANGE BY NEXT WEDNESDAY...SUGGESTING A RETURN TO
SUMMER-LIKE WARMTH IN THE EXTENDED.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
659 PM CDT WED SEP 26 2012
.DISCUSSION...
ISSUED 221 PM CDT WED SEP 26 2012
RAIN CHANCES WILL PERSIST ACROSS SOUTH-CENTRAL ILLINOIS THROUGH
THURSDAY NIGHT...BEFORE A LONG STRETCH OF DRY WEATHER DEVELOPS
ACROSS THE ENTIRE REGION THROUGH NEXT WEEK.
SHORT TERM...TONIGHT THROUGH SATURDAY
19Z/2PM SURFACE ANALYSIS SHOWS A SLOW-MOVING COLD FRONT EXTENDING
FROM JUST SOUTH OF KIKK TO NEAR KUIN. TO THE NORTH OF THE
FRONT...WINDS HAVE BECOME NORTHERLY AND A DRIER AIRMASS IS
BEGINNING TO SETTLE INTO THE FAR NORTHERN KILX CWA. MEANWHILE
SOUTH OF THE BOUNDARY...A MOIST ENVIRONMENT CHARACTERIZED BY
DEWPOINTS IN THE 60S IS SUPPORTING SCATTERED SHOWERS/THUNDER
ACROSS THE REMAINDER OF THE AREA. COLD FRONT IS NOT EXPECTED TO
DROP MUCH FURTHER SOUTH TONIGHT...AS UPPER-LEVEL WAVE CURRENTLY
OVER EASTERN KANSAS WILL IMPEDE ITS SOUTHERN PROGRESS. AS A
RESULT...THINK FRONT WILL ONLY SINK TO JUST SOUTH OF THE I-72
CORRIDOR OVERNIGHT. AS A RESULT...WILL CONTINUE TO CARRY LOW
CHANCE POPS ACROSS THE CENTRAL ZONES...WITH HIGHEST POPS FOCUSED
ALONG/SOUTH OF I-70 WHERE DEEPEST MOISTURE AND STRONGEST LIFT WILL
BE PRESENT. WITH FRONT IN THE VICINITY AND DRIER AIRMASS ONLY
TRICKLING SLOWLY SOUTHWARD...THINK AREAS OF FOG WILL DEVELOP
OVERNIGHT. LAST NIGHT...FOG FORMED IN LOCATIONS NEAR/SOUTH OF THE
BOUNDARY WHERE DEWPOINTS HOVERED IN THE UPPER 50S/LOWER 60S. THOSE
CONDITIONS WILL LIKELY EXIST FURTHER SOUTH TONIGHT...PRIMARILY
ALONG/SOUTH OF I-70. NAM FORECAST SOUNDINGS PROVIDE A STRONG
SIGNAL FOR FOG AT BOTH KMTO AND KLWV AND HRRR VISBY PROGS SUPPORT
THIS AS WELL...SO HAVE INCLUDED AREAS OF FOG ACROSS THE SOUTHEAST
AFTER MIDNIGHT.
ANY FOG WILL GRADUALLY BURN OFF THURSDAY MORNING...HOWEVER SKIES
WILL REMAIN MOSTLY CLOUDY THROUGHOUT THE DAY ACROSS THE SOUTHEAST
AS THE FRONT MAKES ONLY VERY SLOW PROGRESS SOUTHWARD. WILL
CONTINUE WITH CHANCE POPS ALONG AND SOUTH OF A PARIS TO
SHELBYVILLE LINE...WITH DRY CONDITIONS EXPECTED FURTHER NORTH.
BOTH THE NAM AND GFS FINALLY GIVE THE BOUNDARY A GOOD PUSH
SOUTHWARD BY FRIDAY...AS HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. WILL HOLD ON TO A SLIM CHANCE FOR A SHOWER SOUTH OF I-70
INTO FRIDAY IN CASE FRONT IS DELAYED...BUT WILL GO WITH MOSTLY
SUNNY AND DRY CONDITIONS ELSEWHERE.
WITH HIGH PRESSURE BEING THE DOMINANT WEATHER FEATURE...SUNNY
SKIES AND DRY WEATHER IS EXPECTED THIS WEEKEND. TEMPERATURES WILL
REMAIN NEAR NORMAL FOR THIS TIME OF YEAR...WITH DAYTIME HIGHS IN
THE LOWER TO MIDDLE 70S AND OVERNIGHT LOWS IN THE LOWER 50S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
A VIGOROUS SHORT-WAVE WILL DIVE INTO THE GREAT LAKES LATE IN THE
WEEKEND...PUSHING A WEAK COLD FRONT/SURFACE TROUGH THROUGH CENTRAL
ILLINOIS SATURDAY NIGHT INTO SUNDAY. SYSTEM WILL HAVE VERY LITTLE
MOISTURE TO WORK WITH...SO AM ONLY EXPECTING A FEW CLOUDS AS IT
PASSES THROUGH. AFTER THAT...A MAJOR PATTERN CHANGE IS IN STORE
NEXT WEEK. BOTH THE GFS AND ECMWF ARE SHOWING AN UPPER-LEVEL RIDGE
BUILDING ACROSS THE PLAINS INTO THE MIDWEST BY THE MIDDLE AND END
OF THE WEEK. RISING HEIGHTS AND INCREASING SOUTHERLY FLOW WILL
BOOST TEMPS WELL INTO THE 70S BY MONDAY AND TUESDAY...THEN PERHAPS
INTO THE 80S AFTER THAT. BOTH MODELS INDICATE 850MB TEMPS IN THE
15 TO 17C RANGE BY NEXT WEDNESDAY...SUGGESTING A RETURN TO
SUMMER-LIKE WARMTH IN THE EXTENDED.
BARNES
&&
.AVIATION...
ISSUED 659 PM CDT WED SEP 26 2012
LIGHT/VARIABLE WINDS SHOULD CONTINUE TO TREND NORTHEAST TO NORTH
THROUGH THE PERIOD AS HIGH PRESSURE BEGINS TO BUILD INTO THE AREA
BEHIND A DEPARTING FRONTAL BOUNDARY. THE DEPARTURE OF THIS FRONT
WILL ALSO RESULT IN A GRADUAL CLEARING OF THE SKIES FROM NORTH TO
SOUTH. THERE IS STILL A THREAT FOR FOG TO DEVELOP LATER TONIGHT AS
THE SKIES CLEAR...BUT CONFIDENCE NOT HIGH THAT WIDESPREAD FOG WILL
DEVELOP DUE TO DRIER AIR FILTERING INTO THE AREA BEHIND THE FRONT.
SO...WILL NOT INCLUDE FOG AT THIS TIME.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
141 PM EDT TUE SEP 25 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 303 AM EDT TUE SEP 25 2012
A COUPLE OF FRONTS WILL MOVE INTO THE AREA AND LINGER THROUGH THE
END OF THE WORK WEEK...KEEPING CHANCES FOR RAIN ACROSS MUCH OF THE
AREA THROUGH THEN. HIGH PRESSURE WILL THEN BUILD IN AND KEEP MUCH OF
THE WEEKEND INTO EARLY NEXT WEEK DRY. TEMPERATURES WILL RETURN TO
BELOW AVERAGE BY THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1159 AM EDT TUE SEP 25 2012
SATELLITE AND RADAR MOSAIC TRENDS SHOW MUCH OF THE AREA CURRENTLY
DRY AND COULD SEE THAT CONTINUE FOR THE NEXT FEW HOURS. HRRR AND
RAP MODELS CONCUR AND SHOW REDEVELOPMENT LATER THIS
AFTERNOON...MAINLY ACROSS THE CENTRAL AND NORTHERN COUNTIES AFTER
21Z. HOWEVER SATELLITE TRENDS INDICATE POTENTIAL FOR SOME CLEARING IN
THE SOUTH OVER THE NEXT SEVERAL HOURS AND THIS COULD INCREASE
INSTABILITY THERE ENOUGH TO ALLOW FURTHER DEVELOPMENT THERE AS WELL.
WITH THESE THINGS IN MIND HAVE TRENDED POPS DOWN TO CHANCE CATEGORY
THROUGH 21Z...WITH HIGHER CHANCES IN THE NORTH FROM 18 TO 21Z PER
THE MODEL TRENDS MENTIONED...AND THEN LIKELY EVERYWHERE FROM 21 TO
0Z. BASED ON PROGGED INSTABILITY LEFT THUNDER OUT OF THE NORTH UNTIL
AFTER 18Z AND THEN RAMPED UP TO SCATTERED STORMS EVERYWHERE AFTER
21Z.
ALSO DROPPED HIGH TEMPERATURES A BIT IN THE NORTH WHERE IT IS LESS
LIKELY TO SEE MUCH IN THE WAY OF SUNSHINE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE IN
DECENT AGREEMENT WITH OVERALL PATTERN...ALTHOUGH SOME HAVE
DIFFERENCES IN LOCATION OF FRONT. A BLEND OF MODELS LOOKS BEST GIVEN
UNCERTAINTIES IN FRONTAL PLACEMENT LATER IN THE PERIOD.
WITH THE FRONT IN THE AREA TONIGHT AND FORCING CONTINUING...WENT
LIKELY POPS ALL AREAS AGAIN THIS EVENING. DID LOWER THE POPS SOME IN
THE NORTHWEST AFTER 06Z THOUGH AS THE FRONT SINKS SOUTH. TRENDED
TOWARD MAV MOS FOR LOW TEMPERATURES GIVEN THE CLOUDS AND RAINFALL.
AS THE FRONT SLOWLY SINKS ITS WAY SOUTH THROUGH THE REMAINDER OF THE
SHORT TERM...AND UPPER SUPPORT WEAKENS...GRADUALLY LOWERED POPS FROM
NORTH TO SOUTH AND GRADUALLY THROUGH TIME FOR THE REMAINDER OF THE
SHORT TERM.
FOR TEMPERATURES...STUCK FAIRLY CLOSE TO MAV MOS OR A BLEND OF
MET/MAV THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 141 PM EDT TUE SEP 25 2012
THE MAIN FOCUS TO THE EXTENDED WILL BE WHETHER OR NOT TO KEEP LOW
POPS ACROSS THE SOUTH FRIDAY NIGHT AND SATURDAY PER THE CENTRAL
REGION INITIALIZATION. LONG RANGE MODELS ARE IN GOOD AGREEMENT ON A
DRY FORECAST FOR THE REMAINDER OF THE EXTENDED AS A BROAD AREA OF
SURFACE HIGH PRESSURE SETS UP ACROSS THE OHIO VALLEY WITH A LOW
PRESSURE SYSTEM WELL TO THE SOUTH ACROSS THE SOUTHERN STATES AND AN
UPPER LOW NEAR THE SAINT LAWRENCE VALLEY.
WITH THE LONG RANGE MODELS STILL SHOWING A GOOD DEGREE OF MODEL TO
MODEL AND MODEL VERSUS MODEL UNCERTAINTY...WILL ACCEPT THE SMALL
POPS FROM CR INIT FRIDAY NIGHT ACROSS THE WHOLE FORECAST AREA AND
SATURDAY ACROSS JUST OUR FAR SOUTH. WILL ALSO ACCEPT THE SLIGHTLY
BELOW NORMAL TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 251800Z TAF ISSUANCE/...
ISSUED AT 1250 PM EDT TUE SEP 25 2012
IFR AND WORSE CEILINGS HAVE BEEN HOLDING SWAY ACROSS THE TERMINALS
EARLY THIS AFTERNOON...HOWEVER EXPECT CEILINGS TO AT LEAST COME UP
TO MVFR AS SATELLITE WAS SUGGESTING A FEW BREAKS ARE POSSIBLE IN THE
OVERCAST. RADAR SUGGESTS ONLY VCSH THROUGH 20Z. AFTER
20Z...ATMOSPHERE SHOULD BECOME UNSTABLE WITH THE BREAKS IN THE
OVERCAST. WARM AIR ADVECTION WILL CONTINUE TO THE NORTH OF A WARM
FRONT ACROSS WESTERN KENTUCKY AND SOUTH OF A COLD FRONT FROM
SOUTHWESTERN WISCONSIN TO NORTHERN IOWA AND NEBRASKA. IN
ADDITION...MORE UPPER WAVES WILL MOVE THROUGH THE ZONAL FLOW ALOFT.
THUS...EXPECT THE SHOWER AND POSSIBLY THUNDERSTORM ACTIVITY TO PICK
UP AGAIN AND CONTINUE TO BE A THREAT THROUGH THE TAF PERIOD. SOUTH
WINDS AROUND 10 KNOTS THIS AFTERNOON WILL BECOME SOUTHWEST
OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...CP
SHORT TERM...50
LONG TERM....MK
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1250 PM EDT TUE SEP 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 303 AM EDT TUE SEP 25 2012
A COUPLE OF FRONTS WILL MOVE INTO THE AREA AND LINGER THROUGH THE
END OF THE WORK WEEK...KEEPING CHANCES FOR RAIN ACROSS MUCH OF THE
AREA THROUGH THEN. HIGH PRESSURE WILL THEN BUILD IN AND KEEP MUCH OF
THE WEEKEND INTO EARLY NEXT WEEK DRY. TEMPERATURES WILL RETURN TO
BELOW AVERAGE BY THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1159 AM EDT TUE SEP 25 2012
SATELLITE AND RADAR MOSAIC TRENDS SHOW MUCH OF THE AREA CURRENTLY
DRY AND COULD SEE THAT CONTINUE FOR THE NEXT FEW HOURS. HRRR AND
RAP MODELS CONCUR AND SHOW REDEVELOPMENT LATER THIS
AFTERNOON...MAINLY ACROSS THE CENTRAL AND NORTHERN COUNTIES AFTER
21Z. HOWEVER SATELLITE TRENDS INDICATE POTENTIAL FOR SOME CLEARING IN
THE SOUTH OVER THE NEXT SEVERAL HOURS AND THIS COULD INCREASE
INSTABILITY THERE ENOUGH TO ALLOW FURTHER DEVELOPMENT THERE AS WELL.
WITH THESE THINGS IN MIND HAVE TRENDED POPS DOWN TO CHANCE CATEGORY
THROUGH 21Z...WITH HIGHER CHANCES IN THE NORTH FROM 18 TO 21Z PER
THE MODEL TRENDS MENTIONED...AND THEN LIKELY EVERYWHERE FROM 21 TO
0Z. BASED ON PROGGED INSTABILITY LEFT THUNDER OUT OF THE NORTH UNTIL
AFTER 18Z AND THEN RAMPED UP TO SCATTERED STORMS EVERYWHERE AFTER
21Z.
ALSO DROPPED HIGH TEMPERATURES A BIT IN THE NORTH WHERE IT IS LESS
LIKELY TO SEE MUCH IN THE WAY OF SUNSHINE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE IN
DECENT AGREEMENT WITH OVERALL PATTERN...ALTHOUGH SOME HAVE
DIFFERENCES IN LOCATION OF FRONT. A BLEND OF MODELS LOOKS BEST GIVEN
UNCERTAINTIES IN FRONTAL PLACEMENT LATER IN THE PERIOD.
WITH THE FRONT IN THE AREA TONIGHT AND FORCING CONTINUING...WENT
LIKELY POPS ALL AREAS AGAIN THIS EVENING. DID LOWER THE POPS SOME IN
THE NORTHWEST AFTER 06Z THOUGH AS THE FRONT SINKS SOUTH. TRENDED
TOWARD MAV MOS FOR LOW TEMPERATURES GIVEN THE CLOUDS AND RAINFALL.
AS THE FRONT SLOWLY SINKS ITS WAY SOUTH THROUGH THE REMAINDER OF THE
SHORT TERM...AND UPPER SUPPORT WEAKENS...GRADUALLY LOWERED POPS FROM
NORTH TO SOUTH AND GRADUALLY THROUGH TIME FOR THE REMAINDER OF THE
SHORT TERM.
FOR TEMPERATURES...STUCK FAIRLY CLOSE TO MAV MOS OR A BLEND OF
MET/MAV THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 234 AM EDT TUE SEP 25 2012
THE ONLY PERIOD THAT WILL INCLUDE RAIN CHANCES DURING THIS PERIOD
FOR NOW WILL BE SATURDAY AS A FRONTAL BOUNDARY IS EXPECTED TO BE
SAGGING SOUTHWARD OUT OF THE AREA DURING THE DAY. AS FOR THE REST OF
THE PERIOD...CONFIDENCE REMAINS LOW AS THE ECMWF KEEPS A FRONTAL
BOUNDARY FARTHER SOUTH OVER THE TENNESSEE VALLEY WITH BUILDING HIGH
PRESSURE FROM THE NORTH...WHILE THE GFS IS FARTHER NORTH WITH THE
FRONTAL BOUNDARY AND ALSO DROPS AN UPPER LOW OUT OF THE GREAT LAKES
OVER THE AREA. WITH MOISTURE APPEARING RATHER LIMITED IN EITHER CASE
AND A DRY LOWER LEVEL NORTHEAST FLOW PREVALENT IN BOTH CASES HAVE
TRENDED TOWARD A DRIER FORECAST DURING THIS TIME PERIOD FOR NOW.
&&
.AVIATION /DISCUSSION FOR THE 251800Z TAF ISSUANCE/...
ISSUED AT 1250 PM EDT TUE SEP 25 2012
IFR AND WORSE CEILINGS HAVE BEEN HOLDING SWAY ACROSS THE TERMINALS
EARLY THIS AFTERNOON...HOWEVER EXPECT CEILINGS TO AT LEAST COME UP
TO MVFR AS SATELLITE WAS SUGGESTING A FEW BREAKS ARE POSSIBLE IN THE
OVERCAST. RADAR SUGGESTS ONLY VCSH THROUGH 20Z. AFTER
20Z...ATMOSPHERE SHOULD BECOME UNSTABLE WITH THE BREAKS IN THE
OVERCAST. WARM AIR ADVECTION WILL CONTINUE TO THE NORTH OF A WARM
FRONT ACROSS WESTERN KENTUCKY AND SOUTH OF A COLD FRONT FROM
SOUTHWESTERN WISCONSIN TO NORTHERN IOWA AND NEBRASKA. IN
ADDITION...MORE UPPER WAVES WILL MOVE THROUGH THE ZONAL FLOW ALOFT.
THUS...EXPECT THE SHOWER AND POSSIBLY THUNDERSTORM ACTIVITY TO PICK
UP AGAIN AND CONTINUE TO BE A THREAT THROUGH THE TAF PERIOD. SOUTH
WINDS AROUND 10 KNOTS THIS AFTERNOON WILL BECOME SOUTHWEST
OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...CP
SHORT TERM...50
LONG TERM....PUMA
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1159 AM EDT TUE SEP 25 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 303 AM EDT TUE SEP 25 2012
A COUPLE OF FRONTS WILL MOVE INTO THE AREA AND LINGER THROUGH THE
END OF THE WORK WEEK...KEEPING CHANCES FOR RAIN ACROSS MUCH OF THE
AREA THROUGH THEN. HIGH PRESSURE WILL THEN BUILD IN AND KEEP MUCH OF
THE WEEKEND INTO EARLY NEXT WEEK DRY. TEMPERATURES WILL RETURN TO
BELOW AVERAGE BY THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1159 AM EDT TUE SEP 25 2012
SATELLITE AND RADAR MOSAIC TRENDS SHOW MUCH OF THE AREA CURRENTLY
DRY AND COULD SEE THAT CONTINUE FOR THE NEXT FEW HOURS. HRRR AND
RAP MODELS CONCUR AND SHOW REDEVELOPMENT LATER THIS
AFTERNOON...MAINLY ACROSS THE CENTRAL AND NORTHERN COUNTIES AFTER 21Z.
HOWEVER SATELLITE TRENDS INDICATE POTENTIAL FOR SOME CLEARING IN
THE SOUTH OVER THE NEXT SEVERAL HOURS AND THIS COULD INCREASE
INSTABILITY THERE ENOUGH TO ALLOW FURTHER DEVELOPMENT THERE AS
WELL. WITH THESE THINGS IN MIND HAVE TRENDED POPS DOWN TO CHANCE
CATEGORY THROUGH 21Z...WITH HIGHER CHANCES IN THE NORTH FROM 18 TO
21Z PER THE MODEL TRENDS MENTIONED...AND THEN LIKELY EVERYWHERE
FROM 21 TO 0Z. BASED ON PROGGED INSTABILITY LEFT THUNDER OUT OF
THE NORTH UNTIL AFTER 18Z AND THEN RAMPED UP TO SCATTERED STORMS
EVERYWHERE AFTER 21Z.
ALSO DROPPED HIGH TEMPERATURES A BIT IN THE NORTH WHERE IT IS LESS
LIKELY TO SEE MUCH IN THE WAY OF SUNSHINE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE IN
DECENT AGREEMENT WITH OVERALL PATTERN...ALTHOUGH SOME HAVE
DIFFERENCES IN LOCATION OF FRONT. A BLEND OF MODELS LOOKS BEST GIVEN
UNCERTAINTIES IN FRONTAL PLACEMENT LATER IN THE PERIOD.
WITH THE FRONT IN THE AREA TONIGHT AND FORCING CONTINUING...WENT
LIKELY POPS ALL AREAS AGAIN THIS EVENING. DID LOWER THE POPS SOME IN
THE NORTHWEST AFTER 06Z THOUGH AS THE FRONT SINKS SOUTH. TRENDED
TOWARD MAV MOS FOR LOW TEMPERATURES GIVEN THE CLOUDS AND RAINFALL.
AS THE FRONT SLOWLY SINKS ITS WAY SOUTH THROUGH THE REMAINDER OF THE
SHORT TERM...AND UPPER SUPPORT WEAKENS...GRADUALLY LOWERED POPS FROM
NORTH TO SOUTH AND GRADUALLY THROUGH TIME FOR THE REMAINDER OF THE
SHORT TERM.
FOR TEMPERATURES...STUCK FAIRLY CLOSE TO MAV MOS OR A BLEND OF
MET/MAV THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 234 AM EDT TUE SEP 25 2012
THE ONLY PERIOD THAT WILL INCLUDE RAIN CHANCES DURING THIS PERIOD
FOR NOW WILL BE SATURDAY AS A FRONTAL BOUNDARY IS EXPECTED TO BE
SAGGING SOUTHWARD OUT OF THE AREA DURING THE DAY. AS FOR THE REST OF
THE PERIOD...CONFIDENCE REMAINS LOW AS THE ECMWF KEEPS A FRONTAL
BOUNDARY FARTHER SOUTH OVER THE TENNESSEE VALLEY WITH BUILDING HIGH
PRESSURE FROM THE NORTH...WHILE THE GFS IS FARTHER NORTH WITH THE
FRONTAL BOUNDARY AND ALSO DROPS AN UPPER LOW OUT OF THE GREAT LAKES
OVER THE AREA. WITH MOISTURE APPEARING RATHER LIMITED IN EITHER CASE
AND A DRY LOWER LEVEL NORTHEAST FLOW PREVALENT IN BOTH CASES HAVE
TRENDED TOWARD A DRIER FORECAST DURING THIS TIME PERIOD FOR NOW.
&&
.AVIATION /DISCUSSION FOR THE 251500Z TAF UPDATES/...
ISSUED AT 1031 AM EDT TUE SEP 25 2012
TRENDS HAVE BEEN FOR MVFR OR WORSE CEILINGS THROUGH 16Z OR
LATER...SO AT LEAST HAD TO TEMPO LOW CEILINGS FOR ALL THE SITES WITH
HUF THE WORST AT 5K FEET. OTHERWISE...LIGHTNING AND RADAR TRENDS
SUGGEST TEMPO TS GROUPS AT HUF AND BMG WITH ONLY TEMPO -SHRA AT IND
AND LAF THROUGH 16Z-18Z.
PREVIOUS DISCUSSION FOLLOWS...
VFR CIGS ARE EXPECTED TO DETERIORATE TO MVFR DURING MUCH OF THE
PERIOD.
RADAR TRENDS SHOW AN AREA OF SHRA AND TSRA JUST WEST OF INDIANA
PROGRESSING EAST. PROPAGATION SUGGESTS THIS AREA SHOULD REACH OUR
AREA SHORTLY AFTER ISSUANCE TIME...HOWEVER TSRA COVER APPEARS TO
BECOME LESS WIDESPREAD AS THE SYSTEM APPROACHES. ACTIVE WEATHER
PATTERN WILL CONTINUE TODAY. AFTER THIS MORNINGS WAVE
PASSES...ANOTHER S/W LOOKS TO PUSH THROUGH THE AREA DURING THE
EVENING HOURS AS TIME HEIGHTS AGAIN SHOW DEEP SATURATION AND
STRONG LIFT.
AS THAT SYSTEM DEPARTS...LIGHT WINDS AND RECENT RAIN WILL LEAD TO
GOOD CONDITIONS FOR FOG FORMATION WITH MVFR TO IFR CONDITIONS
EXPECTED TOWARD 12Z WED.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...CP
SHORT TERM...50
LONG TERM....PUMA
AVIATION...JP/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
414 AM EDT TUE SEP 25 2012
.UPDATE...
AVIATION SECTION UPDATED
&&
.SYNOPSIS...
ISSUED AT 303 AM EDT TUE SEP 25 2012
A COUPLE OF FRONTS WILL MOVE INTO THE AREA AND LINGER THROUGH THE
END OF THE WORK WEEK...KEEPING CHANCES FOR RAIN ACROSS MUCH OF THE
AREA THROUGH THEN. HIGH PRESSURE WILL THEN BUILD IN AND KEEP MUCH OF
THE WEEKEND INTO EARLY NEXT WEEK DRY. TEMPERATURES WILL RETURN TO
BELOW AVERAGE BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
ISENTROPIC LIFT WILL INCREASE ACROSS THE FORECAST AREA TODAY AS A
COUPLE OF FRONTAL SYSTEMS APPROACH THE AREA...ALONG WITH AN UPPER
WAVE. THE UPPER WAVE WILL HAVE A WEAK JET STREAK WITH IT AND WILL
ALSO PROVIDE BROADER SCALE FORCING.
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS MISSOURI AT THE
MOMENT. THESE WILL MOVE EAST INTO THE AREA THIS MORNING. THEY WILL
FIRST HAVE TO OVERCOME THE DRY AIR AT THE SURFACE...BUT THIS IS
BEING DONE QUICKLY AT THE MOMENT ACROSS NORTHERN MISSOURI.
WITH THE RAINFALL ALREADY DEVELOPING TO THE WEST...AND MULTIPLE
SOURCES OF LIFT MOVING ACROSS THE FORECAST AREA...WENT AHEAD AND
WENT LIKELY POPS ALL AREAS TODAY. SOME MODELS ARE HINTING AT SOME
DRY HOURS AGAIN DURING PART OF THE AFTERNOON...BUT CONFIDENCE IN
TIMING IS TOO LOW TO TRY AND PUT THIS DETAIL IN THE FORECAST AT THE
MOMENT.
GRIDDED MOS GUIDANCE LOOKS REASONABLE FOR HIGH TEMPERATURES
TODAY...SO STUCK CLOSE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE IN
DECENT AGREEMENT WITH OVERALL PATTERN...ALTHOUGH SOME HAVE
DIFFERENCES IN LOCATION OF FRONT. A BLEND OF MODELS LOOKS BEST GIVEN
UNCERTAINTIES IN FRONTAL PLACEMENT LATER IN THE PERIOD.
WITH THE FRONT IN THE AREA TONIGHT AND FORCING CONTINUING...WENT
LIKELY POPS ALL AREAS AGAIN THIS EVENING. DID LOWER THE POPS SOME IN
THE NORTHWEST AFTER 06Z THOUGH AS THE FRONT SINKS SOUTH. TRENDED
TOWARD MAV MOS FOR LOW TEMPERATURES GIVEN THE CLOUDS AND RAINFALL.
AS THE FRONT SLOWLY SINKS ITS WAY SOUTH THROUGH THE REMAINDER OF THE
SHORT TERM...AND UPPER SUPPORT WEAKENS...GRADUALLY LOWERED POPS FROM
NORTH TO SOUTH AND GRADUALLY THROUGH TIME FOR THE REMAINDER OF THE
SHORT TERM.
FOR TEMPERATURES...STUCK FAIRLY CLOSE TO MAV MOS OR A BLEND OF
MET/MAV THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 234 AM EDT TUE SEP 25 2012
THE ONLY PERIOD THAT WILL INCLUDE RAIN CHANCES DURING THIS PERIOD
FOR NOW WILL BE SATURDAY AS A FRONTAL BOUNDARY IS EXPECTED TO BE
SAGGING SOUTHWARD OUT OF THE AREA DURING THE DAY. AS FOR THE REST OF
THE PERIOD...CONFIDENCE REMAINS LOW AS THE ECMWF KEEPS A FRONTAL
BOUNDARY FARTHER SOUTH OVER THE TENNESSEE VALLEY WITH BUILDING HIGH
PRESSURE FROM THE NORTH...WHILE THE GFS IS FARTHER NORTH WITH THE
FRONTAL BOUNDARY AND ALSO DROPS AN UPPER LOW OUT OF THE GREAT LAKES
OVER THE AREA. WITH MOISTURE APPEARING RATHER LIMITED IN EITHER CASE
AND A DRY LOWER LEVEL NORTHEAST FLOW PREVALENT IN BOTH CASES HAVE
TRENDED TOWARD A DRIER FORECAST DURING THIS TIME PERIOD FOR NOW.
&&
.AVIATION /DISCUSSION FOR THE 250900Z IND TAF UPDATE/...
ONGOING TAF IN GOOD SHAPE AS TSRA CONTINUE TO DEVELOP IN THE
MISSISSIPPI RIVER VALLEY AND MOVE EAST WITH AN ASSOCIATED SHORT
WAVE. RADAR TIME OF ARRIVAL TOOL INDICATE TSRA SHOULD REACH THE
IND AREA BY 13Z-15Z AND HAVE TRENDED THE ONGOING TAF IN THAT
MANNER. IN THE MEANTIME THE ONGOING VFR CIGS ARE GOOD TO GO.
PREVIOUS DISCUSSION BELOW
/DISCUSSION FOR 250600Z TAF ISSUANCE/... ISSUED AT 1200 AM EDT TUE
SEP 25 2012
VFR CONDITIONS EXPECTED THROUGH DAYBREAK...POSSIBLE PERIODS OF MVFR
CONDITIONS TUESDAY MORNING.
WARM ADVECTION HAS COMMENCED WITH A SLOWLY EXPANDING AREA OF
STRATOCU INTO THE FORECAST AREA. RAP SOUNDINGS AND RH PROGS INDICATE
THIS SHOULD CONTINUE TO EXPAND ACROSS THE TERMINALS OVER THE NEXT
FEW HOURS BEFORE POSSIBLY DIMINISHING TO A HIGHER MID LEVEL DECK FOR
A SHORT PERIOD OF TIME. AS STRONGER FORCING ALOFT AND ISENTROPIC
LIFT EXPAND INTO THE REGION TOWARDS DAYBREAK HOWEVER...LOWER
CEILINGS SHOULD REESTABLISH OVER CENTRAL INDIANA. OUTSIDE OF A FEW
SPRINKLES...EXPECT IT WILL TAKE UNTIL BETTER LIFT ARRIVES NEAR 12Z
FOR ANY SUBSTANTIAL PRECIP TO IMPACT THE TERMINALS.
WIDESPREAD RAINFALL IS ANTICIPATED BETWEEN 12 AND 18Z AS A MID LEVEL
SHORTWAVE MOVES THROUGH THE REGION. POTENTIAL FOR CEILINGS TO DIP
INTO MVFR CATEGORY WITHIN HEAVIER PRECIP DURING THE MORNING. ANY
CONVECTION LIKELY TO BE MORE SCATTERED IN COVERAGE DURING THE
AFTERNOON AS ADDITIONAL DISTURBANCES ALOFT TRACK THROUGH THE REGION.
HAVE HELD ONTO VCTS MENTION ALL AFTERNOON WITH UNSTABLE AIRMASS
PRESENT. AN EXPANSION IN CONVECTIVE COVERAGE WILL LIKELY OCCUR AGAIN
THIS EVENING AS A LOW LEVEL JET NOSES INTO THE REGION...AND WILL
CARRY PREVAILING SHOWERS WITH VCTS ONCE AGAIN AT ALL TERMINALS. S/SW
WINDS EXPECTED THROUGHOUT THE FORECAST PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....PUMA
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
303 AM EDT TUE SEP 25 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 303 AM EDT TUE SEP 25 2012
A COUPLE OF FRONTS WILL MOVE INTO THE AREA AND LINGER THROUGH THE
END OF THE WORK WEEK...KEEPING CHANCES FOR RAIN ACROSS MUCH OF THE
AREA THROUGH THEN. HIGH PRESSURE WILL THEN BUILD IN AND KEEP MUCH OF
THE WEEKEND INTO EARLY NEXT WEEK DRY. TEMPERATURES WILL RETURN TO
BELOW AVERAGE BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
ISENTROPIC LIFT WILL INCREASE ACROSS THE FORECAST AREA TODAY AS A
COUPLE OF FRONTAL SYSTEMS APPROACH THE AREA...ALONG WITH AN UPPER
WAVE. THE UPPER WAVE WILL HAVE A WEAK JET STREAK WITH IT AND WILL
ALSO PROVIDE BROADER SCALE FORCING.
SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS MISSOURI AT THE
MOMENT. THESE WILL MOVE EAST INTO THE AREA THIS MORNING. THEY WILL
FIRST HAVE TO OVERCOME THE DRY AIR AT THE SURFACE...BUT THIS IS
BEING DONE QUICKLY AT THE MOMENT ACROSS NORTHERN MISSOURI.
WITH THE RAINFALL ALREADY DEVELOPING TO THE WEST...AND MULTIPLE
SOURCES OF LIFT MOVING ACROSS THE FORECAST AREA...WENT AHEAD AND
WENT LIKELY POPS ALL AREAS TODAY. SOME MODELS ARE HINTING AT SOME
DRY HOURS AGAIN DURING PART OF THE AFTERNOON...BUT CONFIDENCE IN
TIMING IS TOO LOW TO TRY AND PUT THIS DETAIL IN THE FORECAST AT THE
MOMENT.
GRIDDED MOS GUIDANCE LOOKS REASONABLE FOR HIGH TEMPERATURES
TODAY...SO STUCK CLOSE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 303 AM EDT TUE SEP 25 2012
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE IN
DECENT AGREEMENT WITH OVERALL PATTERN...ALTHOUGH SOME HAVE
DIFFERENCES IN LOCATION OF FRONT. A BLEND OF MODELS LOOKS BEST GIVEN
UNCERTAINTIES IN FRONTAL PLACEMENT LATER IN THE PERIOD.
WITH THE FRONT IN THE AREA TONIGHT AND FORCING CONTINUING...WENT
LIKELY POPS ALL AREAS AGAIN THIS EVENING. DID LOWER THE POPS SOME IN
THE NORTHWEST AFTER 06Z THOUGH AS THE FRONT SINKS SOUTH. TRENDED
TOWARD MAV MOS FOR LOW TEMPERATURES GIVEN THE CLOUDS AND RAINFALL.
AS THE FRONT SLOWLY SINKS ITS WAY SOUTH THROUGH THE REMAINDER OF THE
SHORT TERM...AND UPPER SUPPORT WEAKENS...GRADUALLY LOWERED POPS FROM
NORTH TO SOUTH AND GRADUALLY THROUGH TIME FOR THE REMAINDER OF THE
SHORT TERM.
FOR TEMPERATURES...STUCK FAIRLY CLOSE TO MAV MOS OR A BLEND OF
MET/MAV THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 234 AM EDT TUE SEP 25 2012
THE ONLY PERIOD THAT WILL INCLUDE RAIN CHANCES DURING THIS PERIOD
FOR NOW WILL BE SATURDAY AS A FRONTAL BOUNDARY IS EXPECTED TO BE
SAGGING SOUTHWARD OUT OF THE AREA DURING THE DAY. AS FOR THE REST OF
THE PERIOD...CONFIDENCE REMAINS LOW AS THE ECMWF KEEPS A FRONTAL
BOUNDARY FARTHER SOUTH OVER THE TENNESSEE VALLEY WITH BUILDING HIGH
PRESSURE FROM THE NORTH...WHILE THE GFS IS FARTHER NORTH WITH THE
FRONTAL BOUNDARY AND ALSO DROPS AN UPPER LOW OUT OF THE GREAT LAKES
OVER THE AREA. WITH MOISTURE APPEARING RATHER LIMITED IN EITHER CASE
AND A DRY LOWER LEVEL NORTHEAST FLOW PREVALENT IN BOTH CASES HAVE
TRENDED TOWARD A DRIER FORECAST DURING THIS TIME PERIOD FOR NOW.
&&
.AVIATION /DISCUSSION FOR 250600Z TAF ISSUANCE/...
ISSUED AT 1200 AM EDT TUE SEP 25 2012
VFR CONDITIONS EXPECTED THROUGH DAYBREAK...POSSIBLE PERIODS OF MVFR
CONDITIONS TUESDAY MORNING.
WARM ADVECTION HAS COMMENCED WITH A SLOWLY EXPANDING AREA OF
STRATOCU INTO THE FORECAST AREA. RAP SOUNDINGS AND RH PROGS INDICATE
THIS SHOULD CONTINUE TO EXPAND ACROSS THE TERMINALS OVER THE NEXT
FEW HOURS BEFORE POSSIBLY DIMINISHING TO A HIGHER MID LEVEL DECK FOR
A SHORT PERIOD OF TIME. AS STRONGER FORCING ALOFT AND ISENTROPIC
LIFT EXPAND INTO THE REGION TOWARDS DAYBREAK HOWEVER...LOWER
CEILINGS SHOULD REESTABLISH OVER CENTRAL INDIANA. OUTSIDE OF A FEW
SPRINKLES...EXPECT IT WILL TAKE UNTIL BETTER LIFT ARRIVES NEAR 12Z
FOR ANY SUBSTANTIAL PRECIP TO IMPACT THE TERMINALS.
WIDESPREAD RAINFALL IS ANTICIPATED BETWEEN 12 AND 18Z AS A MID LEVEL
SHORTWAVE MOVES THROUGH THE REGION. POTENTIAL FOR CEILINGS TO DIP
INTO MVFR CATEGORY WITHIN HEAVIER PRECIP DURING THE MORNING. ANY
CONVECTION LIKELY TO BE MORE SCATTERED IN COVERAGE DURING THE
AFTERNOON AS ADDITIONAL DISTURBANCES ALOFT TRACK THROUGH THE REGION.
HAVE HELD ONTO VCTS MENTION ALL AFTERNOON WITH UNSTABLE AIRMASS
PRESENT. AN EXPANSION IN CONVECTIVE COVERAGE WILL LIKELY OCCUR AGAIN
THIS EVENING AS A LOW LEVEL JET NOSES INTO THE REGION...AND WILL
CARRY PREVAILING SHOWERS WITH VCTS ONCE AGAIN AT ALL TERMINALS. S/SW
WINDS EXPECTED THROUGHOUT THE FORECAST PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....PUMA
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
243 AM EDT TUE SEP 25 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 331 PM EDT MON SEP 24 2012
WARM ADVECTION WILL RAMP UP TONIGHT AND BRING WARMER TEMPERATURES TO
THE AREA. CHANCES FOR RAIN AND THUNDERSTORMS WILL ALSO ARRIVE LATE
TONIGHT WITH AN UPPER WAVE APPROACHING THE AREA. OVER THE COMING
DAYS A FRONT WILL STALL ACROSS CENTRAL INDIANA AND WAVES WILL MOVE
ALONG THIS FRONT KEEPING PRECIPITATION IN THE FORECAST FOR PARTS OF
THE AREA THROUGHOUT THE PERIOD. WITH COLDER AIR BOTTLED BACK UP TO
THE NORTH EXPECT TEMPERATURES TO BE CLOSE TO NORMAL FOR THIS TIME OF
YEAR.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 958 PM EDT MON SEP 24 2012
CUT OUT ALL POPS PRIOR TO 09Z...AND CUT POPS AFTER 09Z TO NO MORE
THAN 45 AND CONFINED ONLY TO SW HALF OF FORECAST AREA.
VERY DRY IN THE LOW LEVELS RIGHT NOW...AND THIS IS THE CASE ALL
THE WAY BACK INTO THE MID MISSISSIPPI VALLEY PER 00Z RAOBS. HAVING
A VERY HARD TIME SEEING CURRENT MID 30S TO LOW 40S DEWPOINTS
MOISTENING UP ENOUGH FOR MORE THAN A CHANCE OF PRECIP LATE.
A LOW LEVEL JET AXIS DOES RAMP UP TO OUR SW LATER TONIGHT...BUT
NEVER QUITE MAKES IT TO THE AREA PRIOR TO 12Z...AND WILL BE
ADVECTING A FAIRLY DRY AIRMASS ACCORDING TO AFOREMENTIONED RAOBS.
THIS ALSO REQUIRED A CUT TO OVERNIGHT LOWS AS WELL...AS LOWER THAN
EXPECTED DEWPOINTS AND LATER CLOUD COVER/POSSIBLE PRECIP WILL
ALLOW TEMPS TO DROP INTO THE UPPER 40S TO AROUND 50. MAV GUIDANCE
APPEARS TO HANDLE THIS WELL AND WAS USED.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 331 PM EDT MON SEP 24 2012
FORECAST FOCUS IS ON POPS. TUESDAY STARTS OUT WITH A LOW LEVEL JET
POINTING AT AND THEN TRAVERSING CENTRAL INDIANA. THIS WILL BRING
ISENTROPIC LIFT ACROSS THE AREA AND ALONG WITH A SHORTWAVE MOVING
ACROSS THE STATE SHOULD BE PLENTY OF FORCING FOR PRECIP. WENT HIGHER
WITH POPS IN SOME PLACES TO KEEP LIKELY GOING ACROSS THE AREA AND
INCLUDED CHANCES FOR THUNDERSTORMS BASED ON INCREASING ELEVATED
INSTABILITY. WITH ELEVATED INSTABILITY AND LOW END SHEAR IN PLACE
COULD SEE SOME MARGINAL HAIL. PRECIPITATION CHANCES LOOK EVEN BETTER
FOR TUESDAY NIGHT WITH A LOW LEVEL JET INCREASING IN STRENGTH AND
SETTING UP JUST TO THE SOUTHWEST. LOOKS LIKE ANOTHER SHORTWAVE WILL
BE MOVING THROUGH AND A FRONT WILL BE SAGGING SOUTH INTO THE AREA.
WITH THESE FEATURES COMBINING INCREASED GUIDANCE POPS TO CATEGORICAL
ACROSS ALL BUT THE NORTH. ON WEDNESDAY KEPT LIKELY POPS GOING SOUTH
OF THE FRONT AND KEPT HIGH CHANCE POPS IN THE SOUTHERN COUNTIES FOR
WEDNESDAY NIGHT WITH THE FRONT STALLING OUT NEAR OR JUST SOUTH OF
THERE. WITH GOOD INSTABILITY SHOWING UP FROM TUESDAY THROUGH
WEDNESDAY KEPT CHANCE FOR THUNDER GOING...DECREASING TO A SLIGHT
CHANCE FOR THUNDER WEDNESDAY NIGHT AND THURSDAY AS FRONT MAY BE
SOUTH OF THE AREA.
FOR TEMPERATURES...GENERALLY FAVORED WARMER GUIDANCE AT NIGHT WITH
WARM ADVECTION...RAIN...AND CLOUD COVER. FOR DAYTIME HIGHS USED A
GUIDANCE AVERAGE.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 234 AM EDT TUE SEP 25 2012
THE ONLY PERIOD THAT WILL INCLUDE RAIN CHANCES DURING THIS PERIOD
FOR NOW WILL BE SATURDAY AS A FRONTAL BOUNDARY IS EXPECTED TO BE
SAGGING SOUTHWARD OUT OF THE AREA DURING THE DAY. AS FOR THE REST
OF THE PERIOD...CONFIDENCE REMAINS LOW AS THE ECMWF KEEPS A
FRONTAL BOUNDARY FARTHER SOUTH OVER THE TENNESSEE VALLEY WITH
BUILDING HIGH PRESSURE FROM THE NORTH...WHILE THE GFS IS FARTHER
NORTH WITH THE FRONTAL BOUNDARY AND ALSO DROPS AN UPPER LOW OUT OF
THE GREAT LAKES OVER THE AREA. WITH MOISTURE APPEARING RATHER
LIMITED IN EITHER CASE AND A DRY LOWER LEVEL NORTHEAST FLOW
PREVALENT IN BOTH CASES HAVE TRENDED TOWARD A DRIER FORECAST
DURING THIS TIME PERIOD FOR NOW.
&&
.AVIATION /DISCUSSION FOR 250600Z TAF ISSUANCE/...
ISSUED AT 1200 AM EDT TUE SEP 25 2012
VFR CONDITIONS EXPECTED THROUGH DAYBREAK...POSSIBLE PERIODS OF MVFR
CONDITIONS TUESDAY MORNING.
WARM ADVECTION HAS COMMENCED WITH A SLOWLY EXPANDING AREA OF
STRATOCU INTO THE FORECAST AREA. RAP SOUNDINGS AND RH PROGS INDICATE
THIS SHOULD CONTINUE TO EXPAND ACROSS THE TERMINALS OVER THE NEXT
FEW HOURS BEFORE POSSIBLY DIMINISHING TO A HIGHER MID LEVEL DECK FOR
A SHORT PERIOD OF TIME. AS STRONGER FORCING ALOFT AND ISENTROPIC
LIFT EXPAND INTO THE REGION TOWARDS DAYBREAK HOWEVER...LOWER
CEILINGS SHOULD REESTABLISH OVER CENTRAL INDIANA. OUTSIDE OF A FEW
SPRINKLES...EXPECT IT WILL TAKE UNTIL BETTER LIFT ARRIVES NEAR 12Z
FOR ANY SUBSTANTIAL PRECIP TO IMPACT THE TERMINALS.
WIDESPREAD RAINFALL IS ANTICIPATED BETWEEN 12 AND 18Z AS A MID LEVEL
SHORTWAVE MOVES THROUGH THE REGION. POTENTIAL FOR CEILINGS TO DIP
INTO MVFR CATEGORY WITHIN HEAVIER PRECIP DURING THE MORNING. ANY
CONVECTION LIKELY TO BE MORE SCATTERED IN COVERAGE DURING THE
AFTERNOON AS ADDITIONAL DISTURBANCES ALOFT TRACK THROUGH THE REGION.
HAVE HELD ONTO VCTS MENTION ALL AFTERNOON WITH UNSTABLE AIRMASS PRESENT.
AN EXPANSION IN CONVECTIVE COVERAGE WILL LIKELY OCCUR AGAIN THIS
EVENING AS A LOW LEVEL JET NOSES INTO THE REGION...AND WILL CARRY
PREVAILING SHOWERS WITH VCTS ONCE AGAIN AT ALL TERMINALS. S/SW WINDS
EXPECTED THROUGHOUT THE FORECAST PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....PUMA
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1200 AM EDT TUE SEP 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 331 PM EDT MON SEP 24 2012
WARM ADVECTION WILL RAMP UP TONIGHT AND BRING WARMER TEMPERATURES TO
THE AREA. CHANCES FOR RAIN AND THUNDERSTORMS WILL ALSO ARRIVE LATE
TONIGHT WITH AN UPPER WAVE APPROACHING THE AREA. OVER THE COMING
DAYS A FRONT WILL STALL ACROSS CENTRAL INDIANA AND WAVES WILL MOVE
ALONG THIS FRONT KEEPING PRECIPITATION IN THE FORECAST FOR PARTS OF
THE AREA THROUGHOUT THE PERIOD. WITH COLDER AIR BOTTLED BACK UP TO
THE NORTH EXPECT TEMPERATURES TO BE CLOSE TO NORMAL FOR THIS TIME OF
YEAR.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 958 PM EDT MON SEP 24 2012
CUT OUT ALL POPS PRIOR TO 09Z...AND CUT POPS AFTER 09Z TO NO MORE
THAN 45 AND CONFINED ONLY TO SW HALF OF FORECAST AREA.
VERY DRY IN THE LOW LEVELS RIGHT NOW...AND THIS IS THE CASE ALL
THE WAY BACK INTO THE MID MISSISSIPPI VALLEY PER 00Z RAOBS. HAVING
A VERY HARD TIME SEEING CURRENT MID 30S TO LOW 40S DEWPOINTS
MOISTENING UP ENOUGH FOR MORE THAN A CHANCE OF PRECIP LATE.
A LOW LEVEL JET AXIS DOES RAMP UP TO OUR SW LATER TONIGHT...BUT
NEVER QUITE MAKES IT TO THE AREA PRIOR TO 12Z...AND WILL BE
ADVECTING A FAIRLY DRY AIRMASS ACCORDING TO AFOREMENTIONED RAOBS.
THIS ALSO REQUIRED A CUT TO OVERNIGHT LOWS AS WELL...AS LOWER THAN
EXPECTED DEWPOINTS AND LATER CLOUD COVER/POSSIBLE PRECIP WILL
ALLOW TEMPS TO DROP INTO THE UPPER 40S TO AROUND 50. MAV GUIDANCE
APPEARS TO HANDLE THIS WELL AND WAS USED.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 331 PM EDT MON SEP 24 2012
FORECAST FOCUS IS ON POPS. TUESDAY STARTS OUT WITH A LOW LEVEL JET
POINTING AT AND THEN TRAVERSING CENTRAL INDIANA. THIS WILL BRING
ISENTROPIC LIFT ACROSS THE AREA AND ALONG WITH A SHORTWAVE MOVING
ACROSS THE STATE SHOULD BE PLENTY OF FORCING FOR PRECIP. WENT HIGHER
WITH POPS IN SOME PLACES TO KEEP LIKELY GOING ACROSS THE AREA AND
INCLUDED CHANCES FOR THUNDERSTORMS BASED ON INCREASING ELEVATED
INSTABILITY. WITH ELEVATED INSTABILITY AND LOW END SHEAR IN PLACE
COULD SEE SOME MARGINAL HAIL. PRECIPITATION CHANCES LOOK EVEN BETTER
FOR TUESDAY NIGHT WITH A LOW LEVEL JET INCREASING IN STRENGTH AND
SETTING UP JUST TO THE SOUTHWEST. LOOKS LIKE ANOTHER SHORTWAVE WILL
BE MOVING THROUGH AND A FRONT WILL BE SAGGING SOUTH INTO THE AREA.
WITH THESE FEATURES COMBINING INCREASED GUIDANCE POPS TO CATEGORICAL
ACROSS ALL BUT THE NORTH. ON WEDNESDAY KEPT LIKELY POPS GOING SOUTH
OF THE FRONT AND KEPT HIGH CHANCE POPS IN THE SOUTHERN COUNTIES FOR
WEDNESDAY NIGHT WITH THE FRONT STALLING OUT NEAR OR JUST SOUTH OF
THERE. WITH GOOD INSTABILITY SHOWING UP FROM TUESDAY THROUGH
WEDNESDAY KEPT CHANCE FOR THUNDER GOING...DECREASING TO A SLIGHT
CHANCE FOR THUNDER WEDNESDAY NIGHT AND THURSDAY AS FRONT MAY BE
SOUTH OF THE AREA.
FOR TEMPERATURES...GENERALLY FAVORED WARMER GUIDANCE AT NIGHT WITH
WARM ADVECTION...RAIN...AND CLOUD COVER. FOR DAYTIME HIGHS USED A
GUIDANCE AVERAGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 216 PM EDT MON SEP 23 2012
MAIN FOCUS WITH THE EXTENDED WITH BE POPS AND TEMPERATURES. MODELS
ARE NOW IN A BIT CLOSER AGREEMENT ON SLIDING AN UPPER TROUGH
SOUTHEAST ACROSS THE OHIO VALLEY LATE IN THE WEEKEND AND EARLY NEXT
WEEK AS IT PHASES WITH THE PERSISTENT EASTERN CANADIAN VORTEX. THIS
SHOULD KEEP THE MIDWEEK FRONT WELL SOUTH OF CENTRAL INDIANA ACROSS
THE SOUTHERN STATES THROUGH THE EXTENDED. HOWEVER...HPC IS
SUGGESTING A SECONDARY FRONT MAY MOVE THROUGH THE AREA FRIDAY
NIGHT..AND SEVERAL UPPER WAVES WILL DROP SOUTHEAST ACROSS THE OHIO
VALLEY IN NORTHWEST FLOW ON THE BACK SIDE OF THE TROUGH.
SO...DESPITE THE MODELS ALL GOING WITH LITTLE TO ANY QPF AFTER
FRIDAY...WILL GENERALLY ACCEPT THE LOW POPS FOR MOST PERIODS FROM
THE CENTRAL REGION INITIALIZATION. MODEL TO MODEL AND MODEL VERSUS
MODEL CONSISTENCY HAS JUST NOT BEEN GOOD ENOUGH TO DEVIATE MUCH AWAY
FROM THEM IN EITHER POPS OR TEMPERATURES. WITH THAT IN MIND...WILL
STICK WITH THE SLIGHTLY BELOW TEMPERATURES AS WELL FROM THE CR INIT.
&&
.AVIATION /DISCUSSION FOR 250300Z TAF UPDATE/...
ISSUED AT 1200 AM EDT TUE SEP 25 2012
VFR CONDITIONS EXPECTED THROUGH DAYBREAK...POSSIBLE PERIODS OF MVFR
CONDITIONS TUESDAY MORNING.
WARM ADVECTION HAS COMMENCED WITH A SLOWLY EXPANDING AREA OF
STRATOCU INTO THE FORECAST AREA. RAP SOUNDINGS AND RH PROGS INDICATE
THIS SHOULD CONTINUE TO EXPAND ACROSS THE TERMINALS OVER THE NEXT
FEW HOURS BEFORE POSSIBLY DIMINISHING TO A HIGHER MID LEVEL DECK FOR
A SHORT PERIOD OF TIME. AS STRONGER FORCING ALOFT AND ISENTROPIC
LIFT EXPAND INTO THE REGION TOWARDS DAYBREAK HOWEVER...LOWER
CEILINGS SHOULD REESTABLISH OVER CENTRAL INDIANA. OUTSIDE OF A FEW
SPRINKLES...EXPECT IT WILL TAKE UNTIL BETTER LIFT ARRIVES NEAR 12Z
FOR ANY SUBSTANTIAL PRECIP TO IMPACT THE TERMINALS.
WIDESPREAD RAINFALL IS ANTICIPATED BETWEEN 12 AND 18Z AS A MID LEVEL
SHORTWAVE MOVES THROUGH THE REGION. POTENTIAL FOR CEILINGS TO DIP
INTO MVFR CATEGORY WITHIN HEAVIER PRECIP DURING THE MORNING. ANY
CONVECTION LIKELY TO BE MORE SCATTERED IN COVERAGE DURING THE
AFTERNOON AS ADDITIONAL DISTURBANCES ALOFT TRACK THROUGH THE REGION.
HAVE HELD ONTO VCTS MENTION ALL AFTERNOON WITH UNSTABLE AIRMASS PRESENT.
AN EXPANSION IN CONVECTIVE COVERAGE WILL LIKELY OCCUR AGAIN THIS
EVENING AS A LOW LEVEL JET NOSES INTO THE REGION...AND WILL CARRY
PREVAILING SHOWERS WITH VCTS ONCE AGAIN AT ALL TERMINALS. S/SW WINDS
EXPECTED THROUGHOUT THE FORECAST PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...NIELD
SHORT TERM...CP
LONG TERM....MK
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS WICHITA KS
700 PM CDT WED SEP 26 2012
.AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
EARLY THIS EVENING A STATIONARY FRONT EXTENDED FROM THE TX PANHANDLE
JUST N OF KAMA DUE E ACROSS CNTRL OK TO NRN AR. ANTICIPATE THE FRONT
TO REMAIN SITUATED OVER THESE AREAS FOR MOST OF THE NIGHT & AS SUCH
BULK OF TONIGHT`S CONVECTION SHOULD LIKEWISE REMAIN OVER OK. IT IS
CONCEIVABLE THAT AS THE LOW-LVL JET DEVELOPS THE 925-MB FRONT MAY GET
FORCED ALMOST DUE N TOWARD THE OK/KS BORDER LATE TONIGHT. WITH SOME
INDICATION THAT THE FRONT MAY LIFT FURTHER N OVER SE KS HAVE LIMITED
"VCTS" MENTION TO KCNU EFFECTIVE 06Z WITH CONVECTION ELEVATED IN
NATURE. TSRA POTENTIAL CONTINUES FOR REMAINDER OF TAF PERIOD WITH
GREATEST EXISTING ACROSS SC & SE KS ON THU WHERE NO DOUBT CLOSER TO
THE AFORE-MENTIONED FRONT.
&&
.PREV DISCUSSION... /ISSUED 229 PM CDT WED SEP 26 2012/
DISCUSSION...
SYNOPSIS...THE MCV LEFT FROM LAST NIGHTS CONVECTION WAS CENTERED
ABOUT 55 MILES NORTHWEST OF SALINA. CONVECTION FROM THIS IS
FESTERING NEAR AND EAST OF THE CENTER...EXTENDING INTO MISSOURI.
A STRONG RESIDENT COLD POOL REMAINED IN PLACE ACROSS THE FORECAST
AREA FOR MUCH OF THE MORNING...MAKING RECOVERY OF THE ATMOSPHERE
QUITE SLOW. OF NOTE AS WELL IN THE VISIBLE IMAGERY ARE GRAVITY
WAVES PROPAGATING AWAY FROM THE CONVECTION TO THE SOUTH AND
SOUTHWEST...THE MOST RECENT OF WHICH HAS INCREASING CONVERGENCE
ALONG IT.
THE COLD POOL HAS PUSHED THE COLD FRONT ALL THE WAY INTO OKLAHOMA
AND ARKANSAS...WITH AN 18Z POSITION EXTENDING FROM A
KRUE-KFSM-KOKC-KDDC APPROXIMATION.
FROM 18Z TO 19Z...TEMPERATURES HAVE RISEN INTO THE MID 70S ACROSS
SOUTH-CENTRAL KANSAS WHERE THE COLD POOL HAS NEARLY MIXED OUT. SOME
CUMULUS HAVE STARTED TO FORM IN THIS AREA AS A RESULT.
UPPER LEVEL ANALYSIS ENDING AT 19Z SHOWS AN UPPER LOW CENTERED OVER
THE FOUR CORNERS REGION...WITH IMPULSES OF ENERGY ROTATING AROUND
IT. THESE ARE THE MAIN IMPULSES AFFECTING THE AREA.
ANOTHER DISTURBANCE WAS NOTED IN THE WATER VAPOR IMAGERY MOVING
ALONG THE U.S. CANADIAN BORDER OF CENTRAL MONTANA. A VERY DEEP AREA
OF LOW PRESSURE WAS OVER THE GULF OF ALASKA WITH WEAKENING LOW
PRESSURE OVER NORTHERN QUEBEC.
THE MAIN FORECAST FOCUS WILL BE ON CONVECTION OVER THE NEXT SEVERAL
DAYS.
TONIGHT - THE MAIN FORCING MECHANISM FOR CONVECTION SHOULD ONCE
AGAIN BE LOW LEVEL MOISTURE TRANSPORT INTERSECTING THE FRONT. THE
MOISTURE TRANSPORT VECTORS...ISENTROPIC LIFT AT 305K AND 310K...AND
THE 1000MB-850MB FRONTOGENESIS REALLY ISOLATE WHERE THIS SHOULD
OCCUR. THE BULK OF THE NWP CONTINUE TO FAVOR AN AREA OVER SOUTHEAST
KANSAS. THIS IS EXPECTED TO OCCUR LATE THIS EVENING.
A SECOND AREA SHOULD CONTINUE IN THE VICINITY OF THE MCV...WHERE
CONVECTION FESTERS THIS AFTERNOON. A THIRD AND FINAL AREA OF
CONVECTION WILL MOVE INTO THE AREA FROM THE WEST. THE NAM-WRF
AND THE HRRR BOTH SHOW STORMS MOVING OFF THE HIGH PLAINS INTO THE
WESTERN PART OF THE STATE. THESE REACH THE FORECAST AREA AT VARIOUS
TIMES. THE HRRR /MULTIPLE RUNS FROM 10Z THROUGH 15Z/ BRING THIS
CONVECTION INTO WESTERN KANSAS BY 01Z...THE 26.12Z NAM-WRF BRINGS IT
INTO WESTERN KANSAS BETWEEN 06Z AND 09Z.
THIS HAS A GREAT AFFECT ON THE FORECAST AND WHETHER WE GET
ADDITIONAL CONVECTION ALONG THE SOUTHERN PERIPHERY OF THE FORECAST
AREA. HAVE LOW CONFIDENCE IN TIMING OF THIS SYSTEM. THE LATEST RAP
AT 18Z SHOWS A STRONG LOW LEVEL JET ACROSS THE HIGH PLAINS...WHICH
WOULD FAVOR THE NAM-WRF. STILL...CONFIDENCE IS RATHER LOW.
THURSDAY - ANY ONGOING CONVECTION IN THE MORNING SHOULD GRADUALLY
DIMINISH DURING THE MORNING. DURING THE AFTERNOON...THERE SHOULD BE
ENOUGH RESIDUAL MOISTURE IN THE BOUNDARY LAYER TO ENABLE SOME
ADDITIONAL SHOWERS AND THUNDERSTORMS...THOUGH NOTHING LOOKS
ORGANIZED AT THIS TIME.
FRIDAY THROUGH WEDNESDAY - HIGH PRESSURE MOVES INTO THE
REGION...BOTH THE 26.12Z ECMWF AND THE 26.12Z GFS AGREE ON THAT.
THEY ALSO HAVE A COLD FRONT...ASSOCIATED WITH A LOW IN THE NORTHERN
STREAM UP IN CANADA...MOVING THROUGH THE REGION ON SUNDAY. THIS
FRONT SHOULD BE DRY SINCE THE GULF IS CLOSED OFF.
ON WEDNESDAY...ANOTHER COLD FRONT MOVES SOUTH THEN STALLS OVER THE
REGION. PRECIPITATION CHANCES WITH THIS FRONT SHOULD BE A BIT
BETTER.
LOOKING OUT AHEAD...A SIGNIFICANT PATTERN CHANGE MAY BE UNDERWAY. A
VERY DEEP TROUGH IS FORECAST TO DEVELOP OVER THE WESTERN U.S. THIS
PRODUCES A STRONG DEEP SURFACE LOW OVER THE NATIONS
MID-SECTION...WITH STRONG HIGH PRESSURE OVER THE NORTHWESTERN U.S.
AND CANADA IN THE LEE OF THE ROCKIES. THIS COULD BE THE FIRST
SIGNIFICANT SNOW STORM OF THE SEASON FOR THE NORTHERN PLAINS AND
SOUTHERN CANADA.
COOK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 62 76 61 74 / 40 50 60 50
HUTCHINSON 60 75 60 74 / 30 40 50 40
NEWTON 60 75 60 73 / 30 40 50 40
ELDORADO 61 76 60 73 / 40 40 50 50
WINFIELD-KWLD 64 78 63 75 / 40 50 60 50
RUSSELL 57 74 56 74 / 20 30 40 30
GREAT BEND 58 74 58 74 / 20 40 50 40
SALINA 58 76 57 76 / 70 20 30 30
MCPHERSON 59 75 58 74 / 30 40 40 40
COFFEYVILLE 65 79 63 75 / 80 50 70 60
CHANUTE 63 76 61 74 / 60 50 50 40
IOLA 62 76 60 74 / 50 40 40 40
PARSONS-KPPF 64 78 62 75 / 70 50 60 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
305 PM CDT TUE SEP 25 2012
.DISCUSSION...
SHORT TERM - THROUGH WEDNESDAY...
SURFACE ANALYSIS AT 18Z INDICATED THAT A RATHER WELL DEFINED SURFACE
LOW OVER FAR SOUTH CENTRAL KANSAS AND NORTH CENTRAL OKLAHOMA...NEAR
THE BORDER OF THE TWO STATES. A SURFACE BOUNDARY...WHICH IS A
REMNANT OF THE BOUNDARY WHICH CAUSED OVERNIGHT SHOWERS IN EASTERN
KANSAS AND WESTERN MISSOURI...IS CURRENTLY LOCATED GENERALLY ACROSS
SOUTHEASTERN KANSAS AND MORE SPECIFICALLY ALONG A LINE ROUGHLY FROM
GARNETT KS TO WELLINGTON KS. THIS BOUNDARY WILL LIKELY BE THE FOCUS
FOR SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON INTO THIS
EVENING. CURRENT SURFACE WINDS NORTH AND WEST OF THE BOUNDARY ARE
OUT OF THE E-NE...WHILE WINDS TO THE SOUTH AND EAST OF THE BOUNDARY
ARE MORE FROM THE SW. THESE PARALLEL AND OPPOSING WINDS ARE NOT
CREATING ENOUGH CONVERGENCE AT THE MOMENT TO GET LOW LEVEL UPWARD
MOTION. HOWEVER AS THE LOW SLIDES EASTWARD SURFACE WINDS MAY BACK A
LITTLE IN RESPONSE TO THE LOWS MOVEMENT. MODEL FORECAST SOUNDINGS
FOR SOUTHEAST KANSAS INDICATE THAT A STOUT LOW/MID LEVEL WARM NOSE
WILL REMAIN ESTABLISHED THROUGH ABOUT 22Z. AT THAT TIME CONVECTION
MAY OCCUR ALONG AND NEAR THAT BOUNDARY. FURTHER ENHANCING CONVECTION
POTENTIAL IS DECENT 850 MB CONVERGENCE AS SW 850 MB WINDS AT 20 TO
30 KTS NOSE INTO SLIGHTLY SLOWER 850 MB WINDS ACROSS EAST CENTRAL
KANSAS. MID/UPPER SUPPORT FOR ASCENT SHOULD COME LATER ON TONIGHT AS
A QUICKLY MOVING SHORTWAVE TROUGH CRUISES THROUGH THE AREA. THE
COMBINATION OF THE AFOREMENTIONED FACTORS SHOULD LEAD TO SCATTERED
CONVECTION ACROSS PARTS OF EAST CENTRAL AND SOUTHEAST KANSAS. AS
SURFACE WINDS BECOME MORE BACKED THE BOUNDARY MAY ALSO SHIFT
NORTHWARD...CAUSING AREAS ALONG AND SOUTH OF THE KANSAS TURNPIKE TO
HAVE A CHANCE FOR SOME SHOWERS AND THUNDERSTORMS. RAP MESOANALYSIS
AT 18Z SHOWS THAT AROUND 2500 J/KG OF MLCAPE EXISTS ALONG AND SOUTH
OF THAT BOUNDARY INDICATING THAT ANY UPDRAFT THAT IS ABLE TO GET
GOING WILL HAVE QUITE A BIT OF INSTABILITY TO WORK WITH. UPDRAFTS
WILL ALSO HAVE AROUND 20 KTS OF DEEP SHEAR TO WORK WITH...SO SOME
UPDRAFT PERSISTENCE WILL BE POSSIBLE. THE STRONGER CONVECTIVE CELLS
WILL HAVE THE CAPABILITY TO POTENTIALLY PRODUCE SOME LARGE
HAIL...PERHAPS UP TO QUARTER SIZED. CLOUD BASES MAY BE IN THE 5 KFT
TO 6 KFT RANGE WITH GOOD LOW LEVEL LAPSE RATES AND DRY AIR BELOW THE
CLOUD LAYER...SO STRONG GUSTY WINDS WILL ALSO BE POSSIBLE WITH THE
STRONGEST UPDRAFTS. ALTHOUGH A FEW STORMS ARE EXPECTED TO BE STRONG
THIS AFTERNOON WIDESPREAD SEVERE WEATHER IS NOT EXPECTED...WITH THE
MAIN THREAT AREA EXPECTED TO BE ALONG AND SOUTH OF THE KANSAS
TURNPIKE.
WITH THE BOUNDARY REMAINING NEAR THE FORECAST AREA THROUGH THE NIGHT
PERIODS OF MODERATE TO HEAVY RAIN WILL BE POSSIBLE ACROSS AREAS OF
EAST CENTRAL AND SOUTHEASTERN KANSAS. A FEW SHOWERS WILL ALSO BE
POSSIBLE ON WEDNESDAY AS A CONTINUATION OF TUESDAY NIGHTS SHOWERS
AND THUNDERSTORMS. EXPECT THERE TO BE A RATHER TIGHT GRADIENT
BETWEEN THE HIGHER END POPS SOUTH OF INTERSTATE 70 AND AREAS TO THE
NORTH NEAR THE KS/NE BORDER...WITH THE HIGHEST POPS REMAINING IN
EAST CENTRAL AND SOUTHEAST KANSAS.
JL
MID TERM - WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...
THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH THIS PERIOD AS
THE STATIONARY FRONTAL BOUNDARY IS FORECAST TO REMAIN IN THE
AREA...ALTHOUGH PRECIP CHANCES WILL VARY A BIT BASED ON TIMING OF
MID LEVEL SHORT WAVE TROUGHS AND MINOR NORTH TO SOUTH FLUCTUATIONS
IN THE LOCATION OF THE FRONT. THE EXACT TIMING OF THE WEAK TROUGHS
AND ASSOCIATED ENHANCEMENTS IN PRECIPITATION COVERAGE REMAINS
RATHER DIFFICULT TO PIN POINT AT THIS TIME...BUT IT CURRENTLY
LOOKS LIKE WEDNESDAY EVENING AND THURSDAY NIGHT-FRIDAY MORNING
WILL HAVE THE BEST CHANCES FOR MORE WIDESPREAD PRECIP ACROSS THE
AREA. EVEN THEN...THE RAIN CHANCES WILL INCREASE FROM NORTH TO
SOUTH ACROSS THE AREA AS THERE IS MORE CONFIDENCE IN THE FRONT
SETTING UP SOUTH OF THE AREA THAN IN A NORTHWARD SHIFT. THE SHORT
WAVE SCHEDULED FOR THURSDAY NIGHT INTO FRIDAY MORNING SHOULD BE
STRONG ENOUGH TO PUSH THE FRONT FARTHER TO THE SOUTH AND BRING IN
DRIER AIR FROM THE NORTH. THIS SHOULD EFFECTIVELY CUT OFF THE
PRECIP CHANCES FROM NORTH TO SOUTH LATE FRIDAY INTO FRIDAY NIGHT.
THE POTENTIAL FOR ISOLATED STRONG STORMS AND ISOLATED HEAVY
RAINFALL AMOUNTS WILL CONTINUE THROUGH THE MAJORITY OF THIS
PERIOD. SEVERE POTENTIAL WILL DECREASE WITH TIME AS INSTABILITY
GRADUALLY WANES WITH WEAKER LAPSE RATES ALOFT. HOWEVER...DEEP
LAYER SHEAR WILL INCREASE A BIT WITH SOME LOCAL MAXIMA IN
INSTABILITY WHICH MAY PRESENT SOME LOCALIZED STRONG TO SEVERE
STORM POTENTIAL. THE HEAVY RAIN POTENTIAL IS A RESULT OF PWAT
VALUES INCREASING TO 1.5 INCHES OR HIGHER...CLIMATOLOGICALLY
HIGH... THE PRESENCE OF WIDESPREAD WEAK TO MODERATE INSTABILITY...
AND STORM MOTIONS THAT MAY OCCASIONALLY SUPPORT TRAINING ALONG OR
NEAR THE FRONTAL BOUNDARY. EVEN WITH HEAVY RAIN POTENTIAL...
FLOODING POTENTIAL APPEARS QUITE LOW GIVEN THE SOIL CONDITIONS...
STREAM BASE FLOW LEVELS...AND AVAILABLE WATER STORAGE IN AREA
LAKES AND PONDS.
HIGHS IN THE 70S ARE EXPECTED ONCE AGAIN THURSDAY AND FRIDAY WITH
AMPLE CLOUD COVER IN PLACE. THE CLOUDS WILL ALSO LIMIT THE DIURNAL
TEMPERATURE SWING SO LOWS SHOULD ONLY DROP INTO THE MIDDLE 50S TO
LOWER 60S.
BARJENBRUCH
LONG TERM - SATURDAY THROUGH TUESDAY...
A RATHER DEEP UPPER TROUGH SETTLES SOUTH INTO THE OHIO VALLEY ON
SATURDAY WITH NORTHERLY FLOW ALOFT AND DRY HIGH PRESSURE AT THE
SURFACE. WHILE THE LONG TERM MODEL GUIDANCE DIFFERS SOMEWHAT IN
OVERALL FLOW SOLUTIONS...THE EXPECTED RESULT IS THE SAME AND A
PERIOD OF DRY STABLE CONDITIONS IS EXPECTED FROM SATURDAY THROUGH
THE END OF THE FORECAST PERIOD ON TUESDAY. THERE ARE SOME
INDICATIONS OF A RATHER PERSISTENT BAND OF FRONTOGENESIS AND
ISENTROPIC ASCENT IN CENTRAL TO WESTERN KANSAS ON THE WESTERN
FLANK OF THE SURFACE HIGH BY LATE IN THE WEEKEND...BUT THIS LOOKS
LIKE A SET UP FOR SPRINKLES AT BEST AND HAVE NOT BROUGHT PRECIP
CHANCES INTO THE FORECAST AT THIS TIME. EXPECT TEMPERATURES
TOPPING OUT IN THE 70S WITH LOWS AROUND 50 ESSENTIALLY EVERY DAY
DURING THIS PERIOD OWING TO NEARLY NEUTRAL TEMPERATURE ADVECTION.
THE OCCASIONAL PRESENCE OF CLOUDS VERSUS CLEAR AND CALM CONDITIONS
OVERNIGHT COULD IMPACT LOWS...BUT THERE IS NO CLEAR SIGNAL AT THIS
TIME POINTING TO ANY NIGHTS BEING PARTICULARLY CLEAR AND COLD.
BARJENBRUCH
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS WILL KICK OFF ALONG AND SOUTH OF
INTERSTATE 35 LATER THIS AFTERNOON...BUT SHOULD STAY AWAY FROM
TERMINALS THROUGH THE END OF THE EVENING HOURS. AROUND 06Z STORMS
WILL APPROACH THE TAF SITES...AND MAY REMAIN NEAR AVIATION
TERMINALS THROUGH THE OVERNIGHT HOURS. EXPECT THAT ROUND OF
T-STORMS TO COME TO AN END BY EARLY MORNING. ANOTHER ROUND OF
T-STORMS MAY FORM DURING THE AFTERNOON ON WED NEAR AVN SITES...BUT
WILL LIKELY TAKE PLACE BEYOND THE TIME FRAME OF THIS FCST
ISSUANCE.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
740 PM EDT WED SEP 26 2012
.UPDATE...
ISSUED AT 650 PM EDT WED SEP 26 2012
SCATTERED CONVECTION CONTINUES TO DRIFT ACROSS OUR BLUEGRASS COUNTIES
THIS EVENING WITH RAINFALL THUS FAR LESS THAN 1/4 INCH. THE NEAR TERM
GUIDANCE GENERALLY APPEARS TO HAVE A GOOD HANDLE ON THE SCATTERED
CONVECTION UPSTREAM OVER WRN KY...DEPICTING THIS ACTIVITY TO
DISSIPATE OVER THE NEXT FEW HOURS BEFORE REACHING THE CWA...WITH
RESIDUAL ACTIVITY OVERNIGHT REMAINING BELOW SEVERE LIMITS AND
PREDOMINANTLY AFFECTING AREAS OVER NERN KY. THE CURRENT FORECAST HAS
ALL OF THIS WELL IN HAND...AND GENERALLY ONLY NEEDED MINOR MASSAGING
TO THE TEMP AND DEW PT CURVES HEADING INTO THE OVERNIGHT PERIOD.
METMOS APPEARS TO HAVE A FAIRLY GOOD HANDLE ON THE TEMP/DEW PT REGIME
ATTM...AND IS HINTING AT SOME TYPICAL ERN KY PATCHY VALLEY FOG
TOWARDS DAWN...SO WILL ADD THIS TO THE MIX FOR AREAS GENERALLY ALONG
AND SOUTH OF THE HAL ROGERS/KY 80 CORRIDOR WHERE CLEARER SKIES ARE
EXPECTED TO PREVAIL OVERNIGHT. UPDATED GRIDS HAVE BEEN SENT...AND
FRESH ZONES WILL BE ISSUED SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 309 PM EDT WED SEP 26 2012
QUASI STATIONARY FRONTAL BOUNDARY REMAINS FROM LAKE ONTARIO TO
NORTHERN ILLINOIS...WHILE ANOTHER WEAK BOUNDARY IS ACROSS NORTHERN
KY. A SERIES OF CONVECTIVE COMPLEXES HAS BEEN MOVING ENE THROUGH THE
OH VALLEY...AND THIS SCENARIO LOOKS TO CONTINUE THROUGH THE FORECAST
PERIOD...WITH A GRADUAL SHIFT SOUTH OF THE ACTIVITY AS THE PRIMARY FRONT
SAGS SOUTH. MODEL CONSENSUS IS THAT THE FOCUS OF THE REPEATED RAINS
WILL BE NORTHWEST OF THE FORECAST AREA...AND THUS HEAVIEST RAIN
TOTALS ARE EXPECTED TO REMAIN OUTSIDE OF FORECAST AREA. HPC HAS
PLACED THE EXTREME WESTERN EDGE OF THE FORECAST AREA IN A SLIGHT RISK
FOR EXCESSIVE RAINS. PRECIPITABLE WATER IS FORECAST TO BE IN EXCESS
OF THE 75TH PERCENTILE...BUT NOT TO BECOME TOO EXCESSIVE WITH PW
GETTING UP NEAR 1.5 INCHES. NONE THE LESS IF THE THE REPEATED RAINS
SET UP FURTHER SOUTH THE SITUATION WILL NEED TO BE MONITORED
CLOSELY. HOWEVER FLOOD THREAT FOR OUR AREA LOOKS MINIMAL AT THIS TIME.
CONVECTION CURRENTLY OVER SOUTHEASTERN INDIANA SHOULD REMAIN NORTH
OF THE FORECAST AREA LATE THIS AFTERNOON AND EVENING...BUT MAY
AFFECT THE FAR NORTHERN PART OF THE FORECAST AREA IF DEVELOPMENT
OCCURS FURTHER TO THE SOUTH. CONVECTION NOW OVER SOUTHEASTERN MO IS
MORE LIKELY TO AFFECT THE FORECAST AREA TONIGHT...AND THIS IS PICKED
UP ON BY THE HRRR.
LOW LEVEL JET LOOKS TO INCREASE EARLY TONIGHT...SO THIS SHOULD HELP TO
INCREASE THE PRECIPITATION CHANCES...MAINLY IN THE NORTH. THE
NORTHERN PART OF THE FORECAST AREA ALSO REMAINS IN A SLIGHT RISK FOR
SEVERE THUNDERSTORMS PER THE LATEST SPC DAY 1 OUTLOOK. HOWEVER SINCE
CONVECTION DID NOT DEVELOP THIS AFTERNOON ALONG THE OLD BOUNDARY
CURRENTLY OVER THE AREA IT APPEARS THE THREAT FOR SEVERE WEATHER WILL
BE DECREASING. IT APPEARS WE WILL NEED TO WAIT FOR THE COMPLEX
CURRENTLY DEVELOPING OVER MO TO MOVE ACROSS THE AREA TONIGHT. HOWEVER
BASED ON LATEST HRRR SHORT RANGE GUIDANCE THIS CONVECTION SHOULD
WEAKEN AS IT MOVES INTO OUR AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 309 PM EDT WED SEP 26 2012
MODELS ARE IN FAIR AGREEMENT TO START THE EXTENDED FCST. A SLOWLY
SAGGING TROF EXTENDS FROM WEST TO EAST ACROSS THE COMMONWEALTH. PCPN
IN THE FORM OF WAVES TRACKS ALONG THE FRONTAL ZONE WITH DIFFERENCES
IN THE DETAILS. HIGH PRESSURE FORCES THE FRONTAL ZONE SOUTH OF THE
STATE WITH THE GFS SLIGHTLY QUICKER IN CLEARING OUT THE PCPN. HAVE
CHOSEN TO FOLLOW THIS TREND AS THE HIGH PRESSURE OVER THE NORTHERN
PLAINS INITIALIZES BETTER IN THIS RUN. THIS PLACES CHANCE POPS
ACROSS THE ENTIRE CWA WITH 30S IN THE NORTH AND 50S SOUTH ON FRI.
FRI NIGHT AND SAT SHOWS CLEARING IN THE NORTH WITH CHANCE POPS IN THE
SOUTH FOLLOWED ON SAT NIGHT WITH NO POPS FOR THE ENTIRE AREA. THE DRY
WEATHER THEN CONTINUES THRU THE REMAINDER OF THE FCST AS HIGH
PRESSURE SETTLES OVER THE CNTRL APPALACHIANS AND THE MID ATLANTIC
COAST. THIS HIGH EXTENDS WEST INTO THE CNTRL PLAINS AND CUTS OFF ANY
RETURN FLOW FROM THE GULF. HENCE THE DEWPOINTS WILL DROP AS THE
DRIER AIR SETTLES IN WITH THE PLAINS HIGH WITH VALUES IN THE UPPER
40S AND LOWER 50S. TEMPERATURES WILL START IN THE MID 70S ON FRI BUT
DROP TO THE UPPER 60S WITH THE CLOUDS AND RAIN ON SAT. THEN AS THE
FRONT EASES SOUTH LOOK FOR HIGH TEMPS TO RECOVER INTO THE LOWER 70S
ON SUN AND CONTINUE CLIMBING SLOWLY TO THE MID 70S AGAIN BY WED.
LOWS WILL REMAIN FAIRLY STEADY IN THE 50S WITH MONDAY MORNING THE
COOLEST AS THE MERCURY SHOULD FALL TO AROUND 50.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 735 PM EDT WED SEP 26 2012
CONVECTION CONTINUES ALONG THE OHIO RIVER AND FURTHER UPSTREAM OVER
WRN KY AT ISSUANCE ALONG A QUASI STATIONARY BOUNDARY SLOWLY SAGGING
SOUTHWARD. CIGS ARE GENERALLY EXPECTED TO REMAIN VFR AT THE TAF
SITES THROUGH 12Z WITH CONVECTION UPSTREAM EXPECTED TO DIMINISH
BEFORE REACHING THE 1 75 CORRIDOR. SHOULD THIS ACTIVITY SURVIVE...IT
APPEARS TO BE ON PACE TO REACH KSME AROUND 06Z...BRINGING TEMPO MVFR
CONDITIONS. HOWEVER...NEAR TERM GUIDANCE SUGGESTS THIS ACTIVITY WILL
DISSIPATE BEFORE REACHING THE CUMBERLAND AREA. CANNOT COMPLETELY RULE
OUT SOME PATCHY VALLEY FOG AFFECTING SOME OF TERMINALS THROUGHOUT
SERN KY WHERE SKIES ARE EXPECTED TO REMAIN MORE SCT TO BKN OVERNIGHT.
THE SFC BOUNDARY IS EXPECTED TO BECOME ACTIVE AGAIN ON THURSDAY...
BRINGING A RENEWED...MORE WIDESPREAD THREAT OF CONVECTION TO THE AREA
AFTER 15Z AND CONTINUING THROUGH THE REMAINDER OF THE PERIOD.
SOUTHERLY WINDS WILL REMAIN LIGHT OVERNIGHT BEFORE REENGAGING AFTER
15Z...VEERING TO THE WEST AT AROUND 5 TO 10 KTS THROUGH THE AFTERNOON
AND EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MB
SHORT TERM...SBH
LONG TERM....DUSTY
AVIATION...MB
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
651 PM EDT TUE SEP 25 2012
...Updated Aviation Discussion...
.Short Term (This afternoon through Wednesday Night)...
Issued at 331 PM EDT Tue Sep 25 2012
Morning convective complex continues to head eastward through the
coal fields of eastern Kentucky this afternoon. Satellite and
surface observations reveal clearing skies to the west of our area.
Areas west of I-65 have already cleared out and temperatures are on
the way up. Further east, mid-high level cloud debris remain, but
some clearing is expected to occur by late afternoon and early
evening in those areas. Dry conditions are expected for the
remainder of the afternoon as the atmosphere recovers from this
morning`s storminess. Temperatures will increase this afternoon as
the sun comes back out, but we will not have much time to work with
to get readings all that high. Still think that we`ll see maximum
temperature readings in the mid-upper 70s in the far west with upper
60s-lower 70s in the central and mid-upper 60s in the east.
Later this afternoon and evening, the deterministic NCEP models all
agree on redeveloping convection along a frontal boundary draped to
our north/northwest. While the atmosphere over south-central
Indiana and much of north-central Kentucky has been convectively
overturned, the atmosphere across western/southwestern Kentucky has
largely been undisturbed. High resolution model runs from the
LMK-WRF, SPC WRF, the RAP, and the HRRR all show increasing
instability across southern IL, eastern MO, and western Kentucky
this afternoon. Model proximity soundings generally show an
elevated mixed layer atop a fairly moist near-surface layer. Wind
fields are sheared in both speed and direction and strong lapse
rates aloft should promote vigorous convective development along
and ahead of this front. Severe convection is likely to our west
this evening and tonight, but is highly questionable across the LMK
forecast area due to this morning`s convection.
Current thinking is that we`ll see a line of convection develop to
our northwest this evening and then slide toward the Ohio River
later tonight. As this line encounters our worked over airmass,
we`ll likely see the convection continue, since the wind shear is
fairly decent and we`ll have instability aloft. The near surface
environment looks to remain largely stable, so any storms that we
see would likely result in torrential rains, some hail and quite a
bit of cloud to ground lightning. The remnants of this line may
transverse southward into southern Kentucky late tonight, but
instability and wind shear support may decay before the line gets
that far south. Therefore, the highest chances of precipitation
look to be across southern Indiana and portions of northern Kentucky
with lesser chances as one heads southward toward the Tennessee
border. Lows tonight will be milder with readings only cooling into
the upper 50s to the lower 60s.
Slow moving frontal boundary will only drift southward during the
day on Wednesday and likely become quasi-stationary by Wednesday
afternoon. Multiple mid-level impulses will transverse the region
resulting in multiple clusters of convection moving across the
region. In general, the highest probabilities of precipitation for
Wednesday favor southern Indiana and northern Kentucky with lesser
probabilities as one gets down toward the KY/TN border. Overall
convective evolution is very uncertain given the complex mesoscale
processes involved and where boundaries may lay. It is likely that
one or more MCS`s may develop and propagate eastward during the day
and into the evening hours. Severe threat is there with damaging
winds and large hail being the most likely threats. Temperatures
will be tricky, but we have stuck close to the weighted-model
average which results in upper 70s to the lower 80s in the north
with lower 80s across the south. The latest datasets do show some
forecast convergence on a wave approaching the area tomorrow evening
which results in increasing PoP chances for Wednesday night with
this forecast issuance. Lows Wednesday night will be in the 60s.
.Long Term (Thursday through Tuesday)...
Issued at 300 PM EDT Tue Sep 25 2012
Thursday through Friday...
Quasi-stationary front will remain draped east to west across the
Ohio Valley, with a series of upper disturbances riding along it in
zonal flow. Expect intervals of showers and thunderstorms, but these
will be as hard to time as the individual disturbances, so forecast
confidence is quite low.
Path of least regret at this time is to carry chance POPs for most
of the period. As timing becomes more clear on any of the upper
impulses, the POP forecast may be better refined. Temps will run
near normal by day, and above normal by night with abundant cloud
cover. Still plenty of bust potential as any longer episodes of
precip could really limit the diurnal ranges.
Friday night through Tuesday...
Sharp upper trough will dig into eastern Canada and the Great Lakes,
and help to push the front farther south over the weekend. Precip
chances will be suppressed farther into south-central Kentucky
through Saturday night, and then south of the area Sunday into early
next week. Model consensus is coming together with each successive
run, so this is a higher-confidence forecast than Thu-Fri. More of a
polar air mass will knock temperatures slightly below normal, with
highs in the lower/mid 70s and lows in the lower/mid 50s.
&&
.Aviation (00Z TAF Issuance)...
Issued at 650 PM EDT Tue Sep 25 2012
Showers and thunderstorms along a front in southern Indiana will
slowly sink south overnight. This activity has been very slow to
shift southward and have therefore pushed back the timing of VCTS at
SDF and LEX. This activity still looks like it will stay to the
north of BWG both tonight and through much of tomorrow. Will
therefore keep any mention of precipitation out of that TAF. There
will likely be a lull in the rain tomorrow morning until another
upper level disturbance crosses the area tomorrow afternoon,
bringing another round of showers and storms to SDF and LEX.
Winds will decrease to around 6-8 knots overnight out of the south
to southwest. A LLJ will strengthen towards midnight and pivot
across the area. Winds will increase to around 40 knots at 1800-2000
ft. Surface winds will once again increase and become gusty tomorrow.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......MJ
Long Term........RAS
Aviation.........EER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
332 PM EDT TUE SEP 25 2012
.Short Term (This afternoon through Wednesday Night)...
Issued at 331 PM EDT Tue Sep 25 2012
Morning convective complex continues to head eastward through the
coal fields of eastern Kentucky this afternoon. Satellite and
surface observations reveal clearing skies to the west of our area.
Areas west of I-65 have already cleared out and temperatures are on
the way up. Further east, mid-high level cloud debris remain, but
some clearing is expected to occur by late afternoon and early
evening in those areas. Dry conditions are expected for the
remainder of the afternoon as the atmosphere recovers from this
morning`s storminess. Temperatures will increase this afternoon as
the sun comes back out, but we will not have much time to work with
to get readings all that high. Still think that we`ll see maximum
temperature readings in the mid-upper 70s in the far west with upper
60s-lower 70s in the central and mid-upper 60s in the east.
Later this afternoon and evening, the deterministic NCEP models all
agree on redeveloping convection along a frontal boundary draped to
our north/northwest. While the atmosphere over south-central
Indiana and much of north-central Kentucky has been convectively
overturned, the atmosphere across western/southwestern Kentucky has
largely been undisturbed. High resolution model runs from the
LMK-WRF, SPC WRF, the RAP, and the HRRR all show increasing
instability across southern IL, eastern MO, and western Kentucky
this afternoon. Model proximity soundings generally show an
elevated mixed layer atop a fairly moist near-surface layer. Wind
fields are sheared in both speed and direction and strong lapse
rates aloft should promote vigorous convective development along
and ahead of this front. Severe convection is likely to our west
this evening and tonight, but is highly questionable across the LMK
forecast area due to this morning`s convection.
Current thinking is that we`ll see a line of convection develop to
our northwest this evening and then slide toward the Ohio River
later tonight. As this line encounters our worked over airmass,
we`ll likely see the convection continue, since the wind shear is
fairly decent and we`ll have instability aloft. The near surface
environment looks to remain largely stable, so any storms that we
see would likely result in torrential rains, some hail and quite a
bit of cloud to ground lightning. The remnants of this line may
transverse southward into southern Kentucky late tonight, but
instability and wind shear support may decay before the line gets
that far south. Therefore, the highest chances of precipitation
look to be across southern Indiana and portions of northern Kentucky
with lesser chances as one heads southward toward the Tennessee
border. Lows tonight will be milder with readings only cooling into
the upper 50s to the lower 60s.
Slow moving frontal boundary will only drift southward during the
day on Wednesday and likely become quasi-stationary by Wednesday
afternoon. Multiple mid-level impulses will transverse the region
resulting in multiple clusters of convection moving across the
region. In general, the highest probabilities of precipitation for
Wednesday favor southern Indiana and northern Kentucky with lesser
probabilities as one gets down toward the KY/TN border. Overall
convective evolution is very uncertain given the complex mesoscale
processes involved and where boundaries may lay. It is likely that
one or more MCS`s may develop and propagate eastward during the day
and into the evening hours. Severe threat is there with damaging
winds and large hail being the most likely threats. Temperatures
will be tricky, but we have stuck close to the weighted-model
average which results in upper 70s to the lower 80s in the north
with lower 80s across the south. The latest datasets do show some
forecast convergence on a wave approaching the area tomorrow evening
which results in increasing PoP chances for Wednesday night with
this forecast issuance. Lows Wednesday night will be in the 60s.
.Long Term (Thursday through Tuesday)...
Issued at 300 PM EDT Tue Sep 25 2012
Thursday through Friday...
Quasi-stationary front will remain draped east to west across the
Ohio Valley, with a series of upper disturbances riding along it in
zonal flow. Expect intervals of showers and thunderstorms, but these
will be as hard to time as the individual disturbances, so forecast
confidence is quite low.
Path of least regret at this time is to carry chance POPs for most
of the period. As timing becomes more clear on any of the upper
impulses, the POP forecast may be better refined. Temps will run
near normal by day, and above normal by night with abundant cloud
cover. Still plenty of bust potential as any longer episodes of
precip could really limit the diurnal ranges.
Friday night through Tuesday...
Sharp upper trough will dig into eastern Canada and the Great Lakes,
and help to push the front farther south over the weekend. Precip
chances will be suppressed farther into south-central Kentucky
through Saturday night, and then south of the area Sunday into early
next week. Model consensus is coming together with each successive
run, so this is a higher-confidence forecast than Thu-Fri. More of a
polar air mass will knock temperatures slightly below normal, with
highs in the lower/mid 70s and lows in the lower/mid 50s.
&&
.Aviation (18Z TAF Issuance)...
Issued at 113 PM EDT Tue Sep 25 2012
Convective complex that affected much of the region this morning
continues to head off to the east. Convection has already cleared
KSDF and KBWG, but light-moderate rain showers will continue to
affect KLEX for the first hour of the upcoming TAF period (through
25/19Z).
We expect a lull in the precipitation this afternoon as we`ll be in
the wake of the departing convective complex. Skies and ceilings
are expected to be in the VFR department through much of the
afternoon and into the early evening hours.
Additional convection is expected to develop along a frontal
boundary to our northwest. This frontal boundary is generally along
the I-70 corridor from near KSTL east to KIND. Latest mesoscale
models suggest that convection will develop along this boundary this
afternoon and then eventually sag to the south and southeast this
evening. There are questions regarding the instability across
southern Indiana and northern Kentucky in the wake of this morning`s
convection. Preliminary thinking is that convection may remain
along and north of the Ohio River this evening as per the latest
NCEP models. The higher resolutions models such as the 4km LMK WRF
and 4km SPC WRF suggest that convection may sag into the KLEX and
KSDF terminals after 26/00Z.
Given the low confidence forecast at this time, we plan to just
mention VCTS in at KSDF and KLEX after 26/00Z. For KBWG, conditions
should remain generally VFR this evening and overnight as convection
looks to remain to their north through the TAF period.
Winds this afternoon should generally be out of the south/southwest
and may be gusty at times this afternoon. Feel that gusts will be
less than 20kts. LLWS looks to be a possibility tonight as the
low-level jet should become active once again.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......MJ
Long Term........RAS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
749 AM EDT TUE SEP 25 2012
...Updated Aviation Discussion...
.Forecast Update...
Updated at 635 AM EDT Tue Sep 25 2012
Complex of storms moving into southwest Indiana this morning.
Should cross our southern Indiana and extreme northern Kentucky
counties between 7am to Noon so have updated POPs to 60% for
numerous t-storms. 0.75 inch hail has been reported in eastern
Illinois so will need to watch these storms for small hail as they
move into our counties. Lowered POPs to only 20% over a larger
portion of south central KY for this morning. Only a few radar
echoes (likely virga or a few sprinkles) showing up south of the
main complex. The HRRR has handled convection the best.
&&
.Short Term (Tuesday - Wednesday)...
Issued at 315 AM EDT Tue Sep 25 2012
A complex forecast is in store for the next 24-36 hrs as multiple
upper level disturbances and a nocturnal LLJ spark convective
complexes along a sfc front laid out to our northwest. Have used a
combo of high res model guidance to put some sort of timing to the
waves although this may need to be adjusted given the difficulty in
timing these features.
Early this morning, an upper level wave was diving southeast across
the upper Plains States, and isentropic lift and a LLJ were
increasing from MO/IL and southwest into the lower Plains states/mid
Mississippi River Valley. A warm front was slowly lifting north
over MO/IL as well. A combination of these features was sparking
elevated convection over MO/IL as of 645Z. This convective complex
is expected to continue to develop farther south this morning and
move east mainly impacting our southern Indiana and northern KY
counties between 12-18Z. Lots of virga is noted ahead of the
complex on radar due to dry lower levels. Max QPF amounts look to
be less than a quarter inch north of the Ohio River this morning.
Then most mesoscale models indicate we should see a lull or less
coverage in convection for the early and mid afternoon hours today.
By mid to late afternoon, another storm complex should initiate
along the stalled frontal boundary to our northwest. This complex
of storms will likely move east into southern Indiana and central KY
after 0Z tonight if the 4k NAM is correct. Some of the storms with
this complex could be strong to marginally severe with damaging
winds/large hail the main threats in a narrow window of opportunity
from about 0-3Z tonight. Severity of storms will be dependent on
breaks in the clouds and resultant instability this afternoon
however. South central KY should have the least amount of clouds
and best sfc heating, however, the best mid level flow will be
focused over southern Indiana and northern KY. Thus, this is not an
ideal scenario for severe convection. Will need to monitor cloud
cover/instability this afternoon to get a better handle on storm
strength for this evening. Right now it appears the best location
for strong to severe storms would be over western to west central
KY.
A third round of convection looks likely for Wed although timing and
placement are much less certain than for today. At this point will
broad brush 30-50% POPs over most of the area for Wed afternoon
which looks to be the best time for renewed convection. The LLJ
should be pretty strong Wed morning though so isld-sct waves may
occur Wed morning as well. If convection does not occur Wed
morning/early afternoon and some sfc instability can be achieved, we
may stand a chance at more strong to marginally severe storms Wed
afternoon. Confidence is not great in severe chances...however
forecast soundings look pretty good for winds/hail again if we can
get some instability. The overall wind profile looks better for
Tues night than for Wed afternoon but not by much. Stay tuned for
forecast updates on timing/intensity of storms. Total QPF amounts
from Tues-Wed look to range from 1.5 inches over southern Indiana to
less than a tenth of an inch over south central KY.
As for temperatures, they will be highly dependent on convection and
cloud cover. Will generally assume more clouds over southern
Indiana and northern KY closer to the stalled sfc front. With this
in mind, highs should reach the low 70s over the Bluegrass/southeast
Indiana to low 80s over south central KY near BWG. Lows tonight
should be mild in the lower 60s. Highs Wed should warm into the
upper 70s to mid 80s as we get a little farther into the warm sector.
.Long Term (Wednesday Night - Monday)...
Issued at 321 AM EDT Tue Sep 25 2012
Wednesday Night - Thursday Night...
A frontal boundary will remain draped over the Ohio Valley, slowly
sagging south into central Kentucky through Thursday night. Very
weak zonal flow aloft parallel to the frontal orientation will be
responsible for keeping the boundary in the area, and will continue
mention of scattered showers and thunderstorms through this time
period. At this point, best coverage looks to be Wednesday night and
Thursday across southern Indiana and central Kentucky. Instability
and shear profile looks marginal for severe weather, so overall
threat is low at this time.
Temperatures on Wednesday night should remain mild for this time of
year, generally in the low to mid 60s. The frontal boundary should
be bisecting the CWA from west to east by Thursday afternoon,
resulting in a larger temperature spread from north to south. Look
for highs in the upper 70s north, to lower 80s south. Thursday night
will bring cooler temperatures in the north down to the lower 50s.
South central Kentucky has the best shot at holding on to lower 60s.
Friday - Saturday Night...
By Friday, closed low will begin to slide into the northern Great
Lakes region, with increased northwest flow over the Ohio Valley.
General model consensus takes the frontal boundary to the KY/TN
border in response to the increased westerlies and will buy into
this solution. Have confined the best (scattered) pops across south
central Kentucky. Highs Friday should range from lower 70s north to
upper 70s south. Friday night through Saturday night will bring the
closed low solidly over the Great Lakes region with a fairly strong
consensus (minus Op GFS) in the front and best precipitation chances
in the Tennessee Valley. As the previous forecast alluded to, we may
be void of any noticeable triggering features for precipitation and
therefore pretty dry during this time. Will still mention some
chances especially across the south due to complex upper air pattern
and model uncertainty. Lows Friday and Saturday nights should range
in the low 50s north to upper 50s south. Saturday should again be in
the low to mid 70s across the region.
Sunday - Monday...
Very low confidence in the Sunday/Monday time frame as models
diverge significantly due to the complex upper air pattern. Prefer
to stick with a ECWMF/GEM/GFS ensemble compromise which keeps the
northern cut off low generally over the Great Lakes and southern
stream energy south of us. Cannot rule out one of these features
impacting the area more directly so will mention only small chances
through the end of the forecast period.
&&
.Aviation (Special 13Z TAF Issuance)...
Issued at 748 AM EDT Tue Sep 25 2012
=======================================
13Z Special Update
=======================================
Latest radar imagery shows a convective complex heading generally
eastward at 40kts. Based on this speed, this complex will start to
have induce negative impacts on KSDF within the next hour. These
negative impacts will be short lived as the line moving quickly so a
30-45 minute window of IFR/MVFR conditions due to thunderstorms is
highly likely. Surface winds will continue out of the southeast
ahead of the line and then quickly shift to the west and northwest
after the line passes. Surface winds of VRB15G30KT will be possible.
Previous forecast for KLEX still looks good. Should this line hold
together, it would start inflict negative impacts around KLEX by
25/1430-1500Z.
=======================================
Previous Discussion
=======================================
An upper level disturbance will dive towards the region from the
northwest this morning. At the same time, isentropic lift will
increase along and south of a warm front lifting north to the west
of our region. These features have spurred a convective complex
which looks to impact SDF around 13Z and LEX around 1430Z this
morning with t-storms. MVFR conditions could be realized in these
t-storms and have went ahead with a tempo MVFR group at SDF. LEX
would need to be updated with an MVFR tempo if the complex holds
together and maintains strength. BWG should just see a few showers
if anything this morning. Have used a combo of high res models and
obs to arrive at this soln.
We should see a lull or decrease in showery activity for this
afternoon with models indicating another complex of storms forming
to our west along a stalled frontal boundary by mid to late
afternoon and pushing eastward into the terminals after 0Z tonight.
SDF/LEX will see the best chances of convection for the evening
round of convection. Although no flight restrictions were included
in the TAF period, MVFR conditions will be possible in a moderate to
heavy shower or t-storm.
Winds will stay out of the SSE this morning and then SSW for the
rest of the day turning gusty this afternoon especially during the
anticipated lull in convection with possible breaks in the lower
cloud deck. Late tonight, LLWS will be possible courtesy of a
strong LLJ.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......AMS
Long Term........BJS
Aviation.........MJ/AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
637 AM EDT TUE SEP 25 2012
.Forecast Update...
Updated at 635 AM EDT Tue Sep 25 2012
Complex of storms moving into southwest Indiana this morning.
Should cross our southern Indiana and extreme northern Kentucky
counties between 7am to Noon so have updated POPs to 60% for
numerous t-storms. 0.75 inch hail has been reported in eastern
Illinois so will need to watch these storms for small hail as they
move into our counties. Lowered POPs to only 20% over a larger
portion of south central KY for this morning. Only a few radar
echoes (likely virga or a few sprinkles) showing up south of the
main complex. The HRRR has handled convection the best.
&&
.Short Term (Tuesday - Wednesday)...
Issued at 315 AM EDT Tue Sep 25 2012
A complex forecast is in store for the next 24-36 hrs as multiple
upper level disturbances and a nocturnal LLJ spark convective
complexes along a sfc front laid out to our northwest. Have used a
combo of high res model guidance to put some sort of timing to the
waves although this may need to be adjusted given the difficulty in
timing these features.
Early this morning, an upper level wave was diving southeast across
the upper Plains States, and isentropic lift and a LLJ were
increasing from MO/IL and southwest into the lower Plains states/mid
Mississippi River Valley. A warm front was slowly lifting north
over MO/IL as well. A combination of these features was sparking
elevated convection over MO/IL as of 645Z. This convective complex
is expected to continue to develop farther south this morning and
move east mainly impacting our southern Indiana and northern KY
counties between 12-18Z. Lots of virga is noted ahead of the
complex on radar due to dry lower levels. Max QPF amounts look to
be less than a quarter inch north of the Ohio River this morning.
Then most mesoscale models indicate we should see a lull or less
coverage in convection for the early and mid afternoon hours today.
By mid to late afternoon, another storm complex should initiate
along the stalled frontal boundary to our northwest. This complex
of storms will likely move east into southern Indiana and central KY
after 0Z tonight if the 4k NAM is correct. Some of the storms with
this complex could be strong to marginally severe with damaging
winds/large hail the main threats in a narrow window of opportunity
from about 0-3Z tonight. Severity of storms will be dependent on
breaks in the clouds and resultant instability this afternoon
however. South central KY should have the least amount of clouds
and best sfc heating, however, the best mid level flow will be
focused over southern Indiana and northern KY. Thus, this is not an
ideal scenario for severe convection. Will need to monitor cloud
cover/instability this afternoon to get a better handle on storm
strength for this evening. Right now it appears the best location
for strong to severe storms would be over western to west central
KY.
A third round of convection looks likely for Wed although timing and
placement are much less certain than for today. At this point will
broad brush 30-50% POPs over most of the area for Wed afternoon
which looks to be the best time for renewed convection. The LLJ
should be pretty strong Wed morning though so isld-sct waves may
occur Wed morning as well. If convection does not occur Wed
morning/early afternoon and some sfc instability can be achieved, we
may stand a chance at more strong to marginally severe storms Wed
afternoon. Confidence is not great in severe chances...however
forecast soundings look pretty good for winds/hail again if we can
get some instability. The overall wind profile looks better for
Tues night than for Wed afternoon but not by much. Stay tuned for
forecast updates on timing/intensity of storms. Total QPF amounts
from Tues-Wed look to range from 1.5 inches over southern Indiana to
less than a tenth of an inch over south central KY.
As for temperatures, they will be highly dependent on convection and
cloud cover. Will generally assume more clouds over southern
Indiana and northern KY closer to the stalled sfc front. With this
in mind, highs should reach the low 70s over the Bluegrass/southeast
Indiana to low 80s over south central KY near BWG. Lows tonight
should be mild in the lower 60s. Highs Wed should warm into the
upper 70s to mid 80s as we get a little farther into the warm sector.
.Long Term (Wednesday Night - Monday)...
Issued at 321 AM EDT Tue Sep 25 2012
Wednesday Night - Thursday Night...
A frontal boundary will remain draped over the Ohio Valley, slowly
sagging south into central Kentucky through Thursday night. Very
weak zonal flow aloft parallel to the frontal orientation will be
responsible for keeping the boundary in the area, and will continue
mention of scattered showers and thunderstorms through this time
period. At this point, best coverage looks to be Wednesday night and
Thursday across southern Indiana and central Kentucky. Instability
and shear profile looks marginal for severe weather, so overall
threat is low at this time.
Temperatures on Wednesday night should remain mild for this time of
year, generally in the low to mid 60s. The frontal boundary should
be bisecting the CWA from west to east by Thursday afternoon,
resulting in a larger temperature spread from north to south. Look
for highs in the upper 70s north, to lower 80s south. Thursday night
will bring cooler temperatures in the north down to the lower 50s.
South central Kentucky has the best shot at holding on to lower 60s.
Friday - Saturday Night...
By Friday, closed low will begin to slide into the northern Great
Lakes region, with increased northwest flow over the Ohio Valley.
General model consensus takes the frontal boundary to the KY/TN
border in response to the increased westerlies and will buy into
this solution. Have confined the best (scattered) pops across south
central Kentucky. Highs Friday should range from lower 70s north to
upper 70s south. Friday night through Saturday night will bring the
closed low solidly over the Great Lakes region with a fairly strong
consensus (minus Op GFS) in the front and best precipitation chances
in the Tennessee Valley. As the previous forecast alluded to, we may
be void of any noticeable triggering features for precipitation and
therefore pretty dry during this time. Will still mention some
chances especially across the south due to complex upper air pattern
and model uncertainty. Lows Friday and Saturday nights should range
in the low 50s north to upper 50s south. Saturday should again be in
the low to mid 70s across the region.
Sunday - Monday...
Very low confidence in the Sunday/Monday time frame as models
diverge significantly due to the complex upper air pattern. Prefer
to stick with a ECWMF/GEM/GFS ensemble compromise which keeps the
northern cut off low generally over the Great Lakes and southern
stream energy south of us. Cannot rule out one of these features
impacting the area more directly so will mention only small chances
through the end of the forecast period.
&&
.Aviation (06Z TAF Issuance)...
Issued at 130 AM EDT Tue Sep 25 2012
An upper level disturbance will dive towards the region from the
northwest this morning. At the same time, isentropic lift will
increase along and south of a warm front lifting north to the west
of our region. These features have already begun to produce virga
over portions of MO/IL and are expected to spur a convective complex
this morning before sunrise over MO/IL/IN. This complex of mostly
showers will push east near the Ohio River just after sunrise. Have
used a combo of high res models to arrive at this soln. The exact
track of the complex is still a little uncertain. For now though,
it appears that light shower activity will move into the terminals
between 13-15Z this morning with SDF/LEX having the better chances
at rain showers. Although a rumble of thunder cannot be ruled out,
it is unlikely so will not include with the morning complex of
convection. We should see a lull or decrease in showery activity
for this afternoon with models indicating another complex of storms
forming to our west along a stalled frontal boundary by mid to late
afternoon and pushing eastward into the terminals after 0Z tonight.
Again, SDF/LEX will see the best chances of convection with better
thunder chances for the evening round of convection. Although no
flight restrictions were included in the TAF period, MVFR conditions
will be possible in a moderate to heavy shower or t-storm.
Winds will stay out of the SSE this morning and then SSW for the
rest of the day turning gusty this afternoon especially during the
anticipated lull in convection with possible breaks in the lower
cloud deck. Late tonight, LLWS will be possible courtesy of a
strong LLJ...will go ahead and include in the SDF TAF.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......AMS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
322 PM EDT TUE SEP 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO PUSH OFFSHORE THIS EVENING. A COLD
FRONT WILL APPROACH THE CENTRAL MID ATLANTIC WEDNESDAY AND STALL
ACROSS THE REGION THURSDAY INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
HIGH PRESSURE HAS MOVED OFFSHORE. RETURN FLOW HAS SET UP ON THE BACK
SIDE OF THE HIGH CENTER. TEMPERATURES ARE BETWEEN 5 AND 7 DEGREES
WARMER THAN THIS TIME YESTERDAY...AND DEWPOINTS ARE AROUND 10
DEGREES HIGHER. VISIBLE SATELLITE IMAGERY SHOWS MID AND HIGH LEVEL
CLOUDINESS SPREADING EASTWARD ACROSS THE REGION FROM A CONVECTIVE
SYSTEM ACROSS THE OHIO VALLEY NORTH OF A WARM FRONT.
REGIONAL RADAR SHOWS SCATTERED SHOWERS ACROSS SOUTHERN WV MOVING
EAST. MOST RECENT RUNS OF THE HRRR BREAK THIS PRECIP UP AS IT
CROSSES THE POTOMAC HIGHLANDS. DO THINK THIS IS REASONABLE AS THE
AIRMASS IS RATHER DRY...AND WILL TAKE A WHILE TO MOISTEN THE COLUMN.
THE BEST CHANCES FOR ANY PRECIP SHOULD BE IN THE WEST LATER THIS
EVENING INTO THE OVERNIGHT HOURS AS THE FRONT APPROACHES. PRECIP
AXIS WILL BECOME W TO E ORIENTED DURING THE DAY TOMORROW AS THE
FRONT BEGINS TO STALL OUT OVER THE CWFA. THE BEST CHANCES FOR PRECIP
TOMORROW SHOULD BE ALONG THE MASON DIXON LINE.
SURFACE INSTABILITY WILL BE LIMITED OVERNIGHT...BUT WITH SOME MID
LEVEL FORCING...ISOLATED THUNDERSTORMS WILL BE POSSIBLE OUT WEST.
THUNDERSTORM CHANCES WILL INCREASE TOMORROW...BUT STILL ONLY REMAIN
SCT IN NATURE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A COLD FRONTAL BOUNDARY WILL SETTLE OVER THE REGION THURSDAY INTO
THE WEEKEND...THOUGH PRECIPITATION LOOKS TO GENERALLY BE FROM
SHORTWAVE ENERGY RIDING ALONG THIS BOUNDARY...MAKING PRECISE
PRECIPITATION PREDICTION NOT POSSIBLE AS OF THIS TIME.
WEDNESDAY NIGHT...COLD FRONT PUSHES SOUTH ACROSS THE MASON-DIXON
LINE WITH CHANCE POPS ACROSS THE CWA. MIN TEMPS GENERALLY LOW 60S
UNDER THICK CLOUD COVER.
THURSDAY INTO SATURDAY...COLD FRONT LINGERS ACROSS THE REGION AS LOW
PRESSURE PERSISTS TO THE NORTH OF THE FRONTAL BOUNDARY AND HIGH
PRESSURE TO THE SOUTH. SHORTWAVES FROM THE TROUGH TO THE NORTH LOOK
TO BE MAIN FORCING FOR PRECIP. THEREFORE NO AREA IS EXPECTED TO HAVE
CONTINUAL PRECIP. TOTAL QPF MAY BE HALF INCH...MAYBE MUCH LESS FOR
MOST OF THE AREA WITH PASSING SHOWERS AS THE MAIN CONVECTIVE MODE.
LIFTED INDEX ON THE SOUTH SIDE OF THE FRONT OF -2 TO -4 FROM THE GFS
ALLOWED A SLIGHT CHANCE FOR THUNDER TO BE ADDED /SW OF DC/. EXPECT
NEAR NORMAL TEMPERATURES THROUGH THIS TIME.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THIS WEEKEND INTO NEXT WEEK...STILL A GREAT DIVERGENCE IN MODELS
WITH A MORE SIGNIFICANT LOW DEVELOPING ALONG THE FRONTAL BOUNDARY AND
PUSHING NORTHEAST. WILL HAVE TO KEEP AN EYE OUT FOR MORE SIGNIFICANT
RAINFALL...THOUGH AS OF NOW THE GFS/ECMWF KEEP DEVELOPMENT OFFSHORE.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THICKENING MID AND UPPER LEVEL CLOUDINESS WILL HELP INHIBIT
WIDESPREAD FOG FORMATION OVERNIGHT. SCT SHOWERS ARE
POSSIBLE...MAINLY IN THE WEST TOWARDS SUNRISE.
A COLD FRONT WILL SAG SOUTHWARD ACROSS THE MID ATLANTIC TOMORROW.
SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE...MAINLY ALONG THE
BOUNDARY. KMTN AND KBWI HAVE THE BEST CHANCES TO BE IMPACTED BY ANY
SHOWERS/ISO TSRA DURING THE AFTERNOON.
CIGS SHOULD REMAIN WELL ABOVE 3 KFT THROUGH THE TAF PERIOD.
INTERMITTENT OF PRECIPITATION ACROSS THE TERMINALS WEDNESDAY NIGHT
INTO THE WEEKEND AS A SLOW MOVING COLD FRONT SAGS INTO AND STALLS
OVER THE REGION. RAINFALL GENERALLY LIGHT TO MODERATE.
&&
.MARINE...
SOUTHERLY FLOW CONTINUES TO INCREASE ACROSS THE WATERS THIS
AFTERNOON. DO EXPECT WIND GUSTS TO AROUND 20 KT ACROSS THE LOWER
TIDAL POTOMAC AND MD CHES BAY OVERNIGHT. NO CHANGES TO THE HEADLINES
NEEDED.
GUSTY SLY FLOW IN ADVANCE OF A COLD FRONT WEDNESDAY NIGHT...SMALL
CRAFT ADVISORY UP UNTIL 6AM THURSDAY. THIS SCA WILL LIKELY NOT NEED
TO BE EXTENDED AS THE COLD FRONT STALLS OVER THE CHESAPEAKE BAY
REGION THEN INTO THE WEEKEND BRINGING INTERMITTENT LIGHT TO MODERATE
SHOWERS.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS ARE CURRENTLY RUNNING BETWEEN ONE HALF AND THREE
QUARTERS OF A FOOT ABOVE NORMAL. DO EXPECT GRADUAL RISES IN WATER
LEVELS OVERNIGHT AS PROLONGED SOUTHERLY FLOW CONTINUES. MODEL
FORECASTS DO KEEP VALUES BELOW CRITICAL THRESHOLDS OVERNIGHT.
HOWEVER...MINOR COASTAL FLOODING MAY BE POSSIBLE DURING THE DAY ON
WEDNESDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ530-531-
537>543.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ532>534.
&&
$$
SYNOPSIS...BAJ/NWL
NEAR TERM...NWL
SHORT TERM...BAJ
LONG TERM...BAJ
AVIATION...BAJ/NWL
MARINE...BAJ/NWL
TIDES/COASTAL FLOODING...NWL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EDT TUE SEP 25 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 420 PM EDT TUE SEP 25 2012
WV IMAGERY AND RUC ANALYSIS INDICATED MID/UPPER LEVEL LOW JUST EAST
OF HUDSON BAY WITH TROUGHING TO THE SOUTH DOMINATING THE GREAT LAKES
AND NE CONUS. AN UPSTREAM SHORTWAVE TROUGH WAS LOCATED NW OF LAKE
SUPERIOR AND HELPED SUPPORT AN INCREASE IN SCT DIURNAL SHOWERS FROM
WINNIPEG TO THUNDER BAY ONTARIO. SOME SPRINKLES HAVE ALSO DEVELOPED
EAST OF THE KEWEENAW AND INTO THE HURON MOUNTAINS WITH THE HELP OF
AFTERNOON HEATING AND WEAK LAKE BREEZES. A WEAK PRES GRADIENT AND
WIND FIELD PREVAILED AS HIGH PRESURE FROM SASK/MANITOBA BUILDS INTO
THE NRN GREAT LAKES.
EXPECT SHRA WILL INCREASE LATE TONIGHT AS 850 MB TEMPS FALL TOWARD
-1C AND A WEAK SFC TROF DROPS S ACROSS THE LAKE IN ASSOCIATION WITH
THE SHORTWAVE. WITH LAKE TEMPS ONLY AROUND 10C TO 13C...DELTA/T
VALUES WILL BE MARGINAL FOR LAKE EFFECT PCPN BUT WILL BE AIDED BY
THE SHRTWV/COLD POOL WITH 700 MB TEMPS ALSO DROPPING TO AROUND
-10C.
THE TIMING OF THE TROF WILL ALSO COINCIDE WITH THE MORE FAVORABLE
MIN OF THE DIURNAL CYCLE. WITH LARGE SCALE SUBSIDENCE WITH DIVERGENT
LOW LEVEL ACYC FLOW AND A SHORTER FETCH...LEFT OUT MENTION OF SHRA
WEST OF THE KEWEENAW. AWAY FROM ANY THICKER CLOUDS AND LAKE
INFLUENCE... TEMPS WILL AGAIN DROP AOB FREEZING IN MANY LOCATIONS
OVER THE INTERIOR WEST. ANY LINGERING SHRA IN THE MORNING INTO THE
ERN CWA FAVORED BY NW FLOW WILL DIMINISH AND END BY AFTERNOON AS THE
SFC RIDGE CONTINUES TO BUILD INTO THE AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 420 PM EDT TUE SEP 25 2012
SPLIT FLOW REGIME TO DOMINATE IN THE UPPER LEVELS THROUGH NEXT
WEEKEND WITH HEIGHTS OVER UPPER LAKES STAYING GENERALLY HIGH. ONE
NOTABLE EXCEPTION IS ECMWF AND TO SOME DEGREE GEM-NHEM STILL SHOW
SHORTWAVE TROUGH SLIDING EAST ACROSS NORTHERN CANADA THIS WEEK THEN
DROPPING INTO NORTHERN ONTARIO ON SATURDAY AND THROUGH THE UPPER
GREAT LAKES BY SUNDAY. ECMWF IS FARTHEST WEST WITH UPPER LOW CENTER
AND SUPPOSE WITH ITS SOLUTION THERE COULD END UP BEING SOME SHOWERS
OVER EASTERN CWA SECOND HALF OF THE WEEKEND. ECMWF HAS SHOWN THIS
FOR FOUR MODEL RUNS NOW...SINCE THE 00Z RUN ON 24 SEPT. GFS REALLY
SHOWS NOTHING OF THE SORT WHILE THE GEM-NHEM IS MORE MIDDLE OF THE
ROAD. CONSENSUS POPS KEEPS THINGS DRY FOR NOW...BUT WENT AHEAD AND
NUDGED CLOUD COVER UP OVER THE EAST LATER SATURDAY THROUGH SUNDAY.
WEAK SHORTWAVE TROUGH SLIDES THROUGH AREA NEXT MONDAY BUT LIMITED
MOISTURE RESULTS IN ONLY SLIGHT CHANCES IN THE FORECAST FOR NOW WITH
THE APPROACH OF A SFC TROUGH. PRIMARY IMPACT COULD BE GUSTY SW WINDS
AHEAD OF THE TROUGH SUNDAY INTO MONDAY.
MAIN WEATHER ISSUE THROUGH THE LONG TERM SEEMS TO BE TEMPERATURES
AND FROST/FREEZE POTENTIAL. NOTE THAT EVEN THOUGH WE HAVE
TECHNICALLY ENDED THE FROST/FREEZE PROGRAM FOR THIS FALL AS MANY
AREAS OVER THE REGION HAVE EXPERIENCED BLO FREEZING TEMPS
RECENTLY...MENTION OF FROST IN THE GRIDS REMAINS IN PLACE THROUGH 30
SEPT.
HIGH PRESSURE RIDGE SETTLES OVER THE UPPER LAKES LATER WEDNESDAY
INTO WEDNESDAY EVENING. HIGHS REMAINS OVERHEAD THROUGH SATURDAY.
GIVEN MOSTLY CLEAR SKIES AND RELATIVELY DRY AIR...EXPECT LARGER
DIURNAL TEMPERATURE SWINGS WITH HIGHS WELL INTO THE 60S AND MINS
DIPPING INTO THE 30S. COLDER EXCEPTION WILL BE WEDNESDAY NIGHT AS
RIDGE AXIS DIRECTLY OVERHEAD AND PWATS AS LOW AS 40 PCT OF NORMAL
SHOULD LEAD TO SIGNIFICANT RADIATIONAL COOLING. TWEAKED MINS WELL
BLO FREEZING OVER INTERIOR CWA /LOW-MID 20S FOR FAVORED INLAND COLD
SPOTS/. LACK OF WIND/LAND BREEZE SHOULD EVEN RESULT IN SOME FROST
FORMING PRETTY CLOSE TO THE GREAT LAKES SHORES. WARMER EXCEPTION MAY
BE ON FRIDAY AS BUBBLE OF WARMER AIR ALOFT MOVES ACROSS OUT AHEAD OF
THE UPPER LOW DROPPING ACROSS ONTARIO. POSSIBLE THAT SOME READINGS
COULD PUSH INTO THE 70S IF ALL BREAKS RIGHT. LOWERED DWPNTS SOME FOR
THURSDAY AFTN AND FRIDAY AFTN AS H85 DWPNT DEPRESSIONS ARE HIGHER
THROUGH THAT TIME. EVEN SO...NO FIRE WEATHER CONCERNS ARE EXPECTED
SINCE WINDS STAY LIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 140 PM EDT TUE SEP 25 2012
AN INCREASE IN OVERWATER INSTABILITY AND AN INCREASE IN LOW-LEVEL
MOISTURE FROM THE N...AND DAYTIME HEATING WILL SUSTAIN BKN STRATOCU
THIS AFTERNOON WITH VFR CIGS. COLDER AIR MOVING IN BEHIND A SHRTWV
LATER TONIGHT ALONG WITH A FURTHER INCREASE IN LOW LEVEL MOISTURE
SHOULD LOWER CIGS INTO THE MVFR RANGE. HOWEVER...CONFIDENCE REMAINS
LIMITED WITH RESPECT TO TIMING/CHANCES OF ANY LOWER CIGS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 420 PM EDT TUE SEP 25 2012
HIGH PRES/WEAK PRES GRADIENT WILL GENERALLY DOMINATE FOR THE REST OF
THIS WEEK...RESULTING IN WINDS UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
142 PM EDT TUE SEP 25 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 511 AM EDT TUE SEP 25 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A TROF OVER SE
CANADA INTO THE NE CONUS. REINFORCING SHORTWAVE TROF DROPPED THRU
THE UPPER LAKES LAST EVENING...BRINGING ANOTHER PUSH OF COOLER AIR
INTO THE AREA. AFTER THE SURGE OF WARMER AIR YESTERDAY ON GUSTY W/SW
WINDS AHEAD OF SHORTWAVE...850MB TEMPS ARE BACK DOWN TO 0C ACROSS
LAKE SUPERIOR...BUT ARE STILL AROUND 5C OVER THE FAR SCNTRL FCST
AREA PER LATEST RUC ANALYSIS. RELATIVELY DRY AIR HAS ALSO FOLLOWED
SHORTWAVE INTO UPPER MI...BUT UPSTREAM CWPL SOUNDING AT 00Z SHOWED
NEAR SATURATION FROM ABOUT 900MB TO 700MB. ALTHOUGH RECENT SATELLITE
IMAGERY SHOWS A SLIGHT INCREASE IN LAKE EFFECT CLOUDS...COVERAGE IS
STILL VERY LIMITED. NO SHRA ARE EVIDENT. TO THE N...CANADIAN RADARS
SHOW SOME -SHRA OFF LAKE NIPIGON.
MAIN CONCERN IN THE SHORT TERM WILL MAINLY BE LAKE EFFECT SHRA
POTENTIAL. SHORTWAVE UPSTREAM IN ERN MANITOBA AND FOLLOWING PIECE OF
ENERGY A LITTLE FARTHER N WILL BE ENHANCING FACTORS FOR SHRA
DEVELOPMENT. WITH DEEP LAYER FORCING PER QVECTORS SPREADING OVER THE
AREA TODAY ALONG WITH AN INCREASE IN LOW-LEVEL MOISTURE...EXPECT SOME
-SHRA DEVELOPMENT...BUT THE DISRUPTION OF LAKE EFFECT PROCESSES BY
DAYTIME HEATING WILL BE A SIGNIFICANT NEGATIVE FACTOR. PERIODIC
HEAVY WAVE ACTION ON LAKE SUPERIOR OVER THE LAST WEEK OR SO HAS
RESULTED IN MID LAKE WATER TEMPS FALLING TO 10-13C WHILE READINGS
AROUND 15-16C ARE PROBABLY STILL MORE COMMON OVER THE SRN PORTION OF
THE LAKE. SO OVERWATER INSTABILITY IS A LITTLE MORE MARGINAL...
ESPECIALLY FOR THE MORE DISRUPTIVE DAYTIME HRS. AT THIS POINT...
NOTHING MORE THAN SCHC POPS APPEAR WARRANTED...MAINLY OVER THE
NCNTRL FCST AREA AS DRIER AIR TO THE W SHOULD PREVENT ANY SHRA
DEVELOPMENT OFF WRN LAKE SUPERIOR.
SHRA COVERAGE SHOULD TEND TO INCREASE LATE TONIGHT AS 850MB TEMPS
FALL TOWARD -2C AND A WEAK SFC TROF DROPS S ACROSS THE LAKE IN
ASSOCIATION WITH SHORTWAVE. TIMING OF TROF WILL ALSO COINCIDE WITH
THE MORE FAVORABLE MIN OF THE DIURNAL CYCLE. THUS...HAVE POPS
INCREASING TO CHC OVER THE NCNTRL/NE FCST AREA LATE TONIGHT. LEFT
THE W DRY DUE TO LARGER AREA OF COOLER WATER OVER THE WRN LAKE AND
DUE TO DEEP LAYER QVECTOR DIVERGENCE DOMINATING. SOME OF THE HIGH
RES MODEL GUIDANCE INDICATES -SHRA WILL OCCUR OVER THE W...SO WILL
NEED TO REEXAMINE POTENTIAL AGAIN IN LATER FCSTS. IN THE INTERIOR W
TONIGHT...THERE SHOULD BE A SUFFICIENT LACK OF CLOUDS TO ALLOW TEMPS
TO FALL TO AROUND 30F...RESULTING IN FROST DEVELOPMENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 511 AM EDT TUE SEP 25 2012
SHORTWAVE WILL BE EXITING THE CWA TO THE SE AT THE START OF THE
PERIOD...SETTING UP A PERIOD OF SPLIT FLOW THROUGH THE END OF THE
WEEK. THE NRN STREAM WILL BE SET IN CANADA...WHILE THE SRN STREAM
WILL BE OVER THE SRN HALF OF THE CONUS. THIS WILL ALLOW FOR HIGH
PRESSURE TO SETTLE IN AND PRODUCE A FAIRLY DRY LONG TERM PERIOD.
FORCING FROM THE SHORTWAVE...COMBINING WITH A POCKET OF LLVL
MOISTURE...SHOULD ALLOW SHOWERS TO BE ONGOING OVER SCNTRL/ERN LAKE
SUPERIOR AND ERN UPPER MI. THESE SHOWERS WILL BE AIDED BY ENHANCED
LLVL CONVERGENCE AND INCREASED LK INSTABILITY WITH H850 TEMPS AROUND
1C. THE SHOWERS SHOULD CONTINUE THROUGH MUCH OF THE MORNING...BUT
HIGH PRESSURE BUILDING IN AND THE QUICKLY EXITING SHORTWAVE/MOISTURE
SHOULD BRING A DIMINISHING TREND IN THE EARLY AFTERNOON.
ANTICYCLONIC FLOW INCREASING THROUGH THE DAY AND DRYING ALOFT
LOWERING THE CAPPING INVERSION WILL ALSO DIMINISH THE SHOWERS. WITH
THE CLOUDS IN PLACE FOR MUCH OF THE DAY...EXPECT HIGHS TO ONLY RISE
INTO THE 50S...WITH THE COOLEST VALUES OVER THE N WHERE THE CLOUD
COVER WILL BE THE THICKEST.
THIS HIGH WILL REMAIN IN PLACE THROUGH AT LEAST THURS NIGHT AND LEAD
TO DRY WX OVER UPPER MI. EXPECT A COLD NIGHT WED NIGHT WITH THE HIGH
BEING NEARLY OVERHEAD. PWATS AROUND 50 PERCENT OF NORMAL AND CLEAR
SKIES WILL PROMOTE RADIATIONAL COOLING AND EXPECT LOWS IN THE UPPER
20S AND LOWER 30S OVER MOST INTERIOR LOCATIONS. THIS WILL PRODUCE
ANOTHER DECENT FROST/FREEZE ACROSS THE AREA. SINCE MOST INTERIOR
LOCATIONS HAVE SEEN A FROST OR FREEZE ALREADY THIS MONTH...OUR
ADVISORY/WARNING HEADLINES HAVE ENDED...BUT WILL CONTINUE TO MENTION
FROST DURING THE TRANSITION PERIOD.
OTHER THAN SOME DIURNAL CU OVER THE SE HALF OF UPPER MI THURS
AFTN...EXPECT MOSTLY CLEAR SKIES TO CONTINUE ON THURS AND INTO FRI.
GRADUALLY WARMING H850 TEMPS WILL LEAD TO HIGHS RISING INTO THE 60S
FOR THURS/FRI...WHICH IS BACK TO NORMAL.
THE GREATEST UNCERTAINTY FOR THE LONG TERM FORECAST COMES WITH THE
SHORTWAVE THAT MOVES THROUGH THE NRN STREAM IN ONTARIO ON FRI. THIS
WILL DRAG A WEAK COLD FRONT ACROSS UPPER MI LATE THURS NIGHT AND
INTO FRI...BUT WILL ONLY CAUSE A SLIGHT WINDSHIFT.
THEN...DETERMINISTIC AND ENSEMBLE MODELS ARE STARTING TO TREND
TOWARDS THE SHORTWAVE BECOMING CLOSED/CUT OFF OVER FAR SE ONTARIO ON
SAT AND SLOWLY DRIFTING SSW INTO THE GREAT LKS. CONFIDENCE IS
INCREASING ON THIS OCCURRENCE...BUT THE LOCATION VARIES DEPENDING
ON THE MODEL. AT THIS POINT...WITH MOISTURE NOT EXPECTED TO BE TOO
FAR FROM THE SHORTWAVE WHILE MOVING THROUGH ONTARIO...DON/T THINK
THERE WILL BE MUCH MOISTURE TO WORK WITH WHEN THE TROUGH CUTS OFF.
THEREFORE...WILL CONTINUE TO FOLLOW A DRY FORECAST FOR THE WEEKEND
AS THE GENERAL CONSENSUS OF THE MODELS HAS THE UPPER LOW CENTERED
OVER LK HURON AND WEAK HIGH PRESSURE OVER THE CWA. RIGHT NOW
TEMPERATURES APPEAR TO BE SEASONABLE FOR THE END OF THE WORK WEEK
AND INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 140 PM EDT TUE SEP 25 2012
AN INCREASE IN OVERWATER INSTABILITY AND AN INCREASE IN LOW-LEVEL
MOISTURE FROM THE N...AND DAYTIME HEATING WILL SUSTAIN BKN STRATOCU
THIS AFTERNOON WITH VFR CIGS. COLDER AIR MOVING IN BEHIND A SHRTWV
LATER TONIGHT ALONG WITH A FURTHER INCREASE IN LOW LEVEL MOISTURE
SHOULD LOWER CIGS INTO THE MVFR RANGE. HOWEVER...CONFIDENCE REMAINS
LIMITED WITH RESPECT TO TIMING/CHANCES OF ANY LOWER CIGS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 AM EDT TUE SEP 25 2012
HIGH PRES/WEAK PRES GRADIENT WILL GENERALLY DOMINATE FOR THE REST OF
THIS WEEK...RESULTING IN WINDS UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
723 AM EDT TUE SEP 25 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 511 AM EDT TUE SEP 25 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A TROF OVER SE
CANADA INTO THE NE CONUS. REINFORCING SHORTWAVE TROF DROPPED THRU
THE UPPER LAKES LAST EVENING...BRINGING ANOTHER PUSH OF COOLER AIR
INTO THE AREA. AFTER THE SURGE OF WARMER AIR YESTERDAY ON GUSTY W/SW
WINDS AHEAD OF SHORTWAVE...850MB TEMPS ARE BACK DOWN TO 0C ACROSS
LAKE SUPERIOR...BUT ARE STILL AROUND 5C OVER THE FAR SCNTRL FCST
AREA PER LATEST RUC ANALYSIS. RELATIVELY DRY AIR HAS ALSO FOLLOWED
SHORTWAVE INTO UPPER MI...BUT UPSTREAM CWPL SOUNDING AT 00Z SHOWED
NEAR SATURATION FROM ABOUT 900MB TO 700MB. ALTHOUGH RECENT SATELLITE
IMAGERY SHOWS A SLIGHT INCREASE IN LAKE EFFECT CLOUDS...COVERAGE IS
STILL VERY LIMITED. NO SHRA ARE EVIDENT. TO THE N...CANADIAN RADARS
SHOW SOME -SHRA OFF LAKE NIPIGON.
MAIN CONCERN IN THE SHORT TERM WILL MAINLY BE LAKE EFFECT SHRA
POTENTIAL. SHORTWAVE UPSTREAM IN ERN MANITOBA AND FOLLOWING PIECE OF
ENERGY A LITTLE FARTHER N WILL BE ENHANCING FACTORS FOR SHRA
DEVELOPMENT. WITH DEEP LAYER FORCING PER QVECTORS SPREADING OVER THE
AREA TODAY ALONG WITH AN INCREASE IN LOW-LEVEL MOISTURE...EXPECT SOME
-SHRA DEVELOPMENT...BUT THE DISRUPTION OF LAKE EFFECT PROCESSES BY
DAYTIME HEATING WILL BE A SIGNIFICANT NEGATIVE FACTOR. PERIODIC
HEAVY WAVE ACTION ON LAKE SUPERIOR OVER THE LAST WEEK OR SO HAS
RESULTED IN MID LAKE WATER TEMPS FALLING TO 10-13C WHILE READINGS
AROUND 15-16C ARE PROBABLY STILL MORE COMMON OVER THE SRN PORTION OF
THE LAKE. SO OVERWATER INSTABILITY IS A LITTLE MORE MARGINAL...
ESPECIALLY FOR THE MORE DISRUPTIVE DAYTIME HRS. AT THIS POINT...
NOTHING MORE THAN SCHC POPS APPEAR WARRANTED...MAINLY OVER THE
NCNTRL FCST AREA AS DRIER AIR TO THE W SHOULD PREVENT ANY SHRA
DEVELOPMENT OFF WRN LAKE SUPERIOR.
SHRA COVERAGE SHOULD TEND TO INCREASE LATE TONIGHT AS 850MB TEMPS
FALL TOWARD -2C AND A WEAK SFC TROF DROPS S ACROSS THE LAKE IN
ASSOCIATION WITH SHORTWAVE. TIMING OF TROF WILL ALSO COINCIDE WITH
THE MORE FAVORABLE MIN OF THE DIURNAL CYCLE. THUS...HAVE POPS
INCREASING TO CHC OVER THE NCNTRL/NE FCST AREA LATE TONIGHT. LEFT
THE W DRY DUE TO LARGER AREA OF COOLER WATER OVER THE WRN LAKE AND
DUE TO DEEP LAYER QVECTOR DIVERGENCE DOMINATING. SOME OF THE HIGH
RES MODEL GUIDANCE INDICATES -SHRA WILL OCCUR OVER THE W...SO WILL
NEED TO REEXAMINE POTENTIAL AGAIN IN LATER FCSTS. IN THE INTERIOR W
TONIGHT...THERE SHOULD BE A SUFFICIENT LACK OF CLOUDS TO ALLOW TEMPS
TO FALL TO AROUND 30F...RESULTING IN FROST DEVELOPMENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 511 AM EDT TUE SEP 25 2012
SHORTWAVE WILL BE EXITING THE CWA TO THE SE AT THE START OF THE
PERIOD...SETTING UP A PERIOD OF SPLIT FLOW THROUGH THE END OF THE
WEEK. THE NRN STREAM WILL BE SET IN CANADA...WHILE THE SRN STREAM
WILL BE OVER THE SRN HALF OF THE CONUS. THIS WILL ALLOW FOR HIGH
PRESSURE TO SETTLE IN AND PRODUCE A FAIRLY DRY LONG TERM PERIOD.
FORCING FROM THE SHORTWAVE...COMBINING WITH A POCKET OF LLVL
MOISTURE...SHOULD ALLOW SHOWERS TO BE ONGOING OVER SCNTRL/ERN LAKE
SUPERIOR AND ERN UPPER MI. THESE SHOWERS WILL BE AIDED BY ENHANCED
LLVL CONVERGENCE AND INCREASED LK INSTABILITY WITH H850 TEMPS AROUND
1C. THE SHOWERS SHOULD CONTINUE THROUGH MUCH OF THE MORNING...BUT
HIGH PRESSURE BUILDING IN AND THE QUICKLY EXITING SHORTWAVE/MOISTURE
SHOULD BRING A DIMINISHING TREND IN THE EARLY AFTERNOON.
ANTICYCLONIC FLOW INCREASING THROUGH THE DAY AND DRYING ALOFT
LOWERING THE CAPPING INVERSION WILL ALSO DIMINISH THE SHOWERS. WITH
THE CLOUDS IN PLACE FOR MUCH OF THE DAY...EXPECT HIGHS TO ONLY RISE
INTO THE 50S...WITH THE COOLEST VALUES OVER THE N WHERE THE CLOUD
COVER WILL BE THE THICKEST.
THIS HIGH WILL REMAIN IN PLACE THROUGH AT LEAST THURS NIGHT AND LEAD
TO DRY WX OVER UPPER MI. EXPECT A COLD NIGHT WED NIGHT WITH THE HIGH
BEING NEARLY OVERHEAD. PWATS AROUND 50 PERCENT OF NORMAL AND CLEAR
SKIES WILL PROMOTE RADIATIONAL COOLING AND EXPECT LOWS IN THE UPPER
20S AND LOWER 30S OVER MOST INTERIOR LOCATIONS. THIS WILL PRODUCE
ANOTHER DECENT FROST/FREEZE ACROSS THE AREA. SINCE MOST INTERIOR
LOCATIONS HAVE SEEN A FROST OR FREEZE ALREADY THIS MONTH...OUR
ADVISORY/WARNING HEADLINES HAVE ENDED...BUT WILL CONTINUE TO MENTION
FROST DURING THE TRANSITION PERIOD.
OTHER THAN SOME DIURNAL CU OVER THE SE HALF OF UPPER MI THURS
AFTN...EXPECT MOSTLY CLEAR SKIES TO CONTINUE ON THURS AND INTO FRI.
GRADUALLY WARMING H850 TEMPS WILL LEAD TO HIGHS RISING INTO THE 60S
FOR THURS/FRI...WHICH IS BACK TO NORMAL.
THE GREATEST UNCERTAINTY FOR THE LONG TERM FORECAST COMES WITH THE
SHORTWAVE THAT MOVES THROUGH THE NRN STREAM IN ONTARIO ON FRI. THIS
WILL DRAG A WEAK COLD FRONT ACROSS UPPER MI LATE THURS NIGHT AND
INTO FRI...BUT WILL ONLY CAUSE A SLIGHT WINDSHIFT.
THEN...DETERMINISTIC AND ENSEMBLE MODELS ARE STARTING TO TREND
TOWARDS THE SHORTWAVE BECOMING CLOSED/CUT OFF OVER FAR SE ONTARIO ON
SAT AND SLOWLY DRIFTING SSW INTO THE GREAT LKS. CONFIDENCE IS
INCREASING ON THIS OCCURRENCE...BUT THE LOCATION VARIES DEPENDING
ON THE MODEL. AT THIS POINT...WITH MOISTURE NOT EXPECTED TO BE TOO
FAR FROM THE SHORTWAVE WHILE MOVING THROUGH ONTARIO...DON/T THINK
THERE WILL BE MUCH MOISTURE TO WORK WITH WHEN THE TROUGH CUTS OFF.
THEREFORE...WILL CONTINUE TO FOLLOW A DRY FORECAST FOR THE WEEKEND
AS THE GENERAL CONSENSUS OF THE MODELS HAS THE UPPER LOW CENTERED
OVER LK HURON AND WEAK HIGH PRESSURE OVER THE CWA. RIGHT NOW
TEMPERATURES APPEAR TO BE SEASONABLE FOR THE END OF THE WORK WEEK
AND INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 722 AM EDT TUE SEP 25 2012
AN INCREASE IN OVERWATER INSTABILITY AND AN INCREASE IN LOW-LEVEL
MOISTURE FROM THE N SHOULD RESULT IN SCT/BKN STRATOCU DEVELOPING
THIS MORNING. CIGS SHOULD BE VFR AT KIWD/KCMX. AT KSAW...INCLUDED
HIGH MVFR CIGS DUE TO LONGER OVERWATER FETCH AND PRESENCE OF SOME
MVFR CIGS UPSTREAM IN NRN ONTARIO.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 AM EDT TUE SEP 25 2012
HIGH PRES/WEAK PRES GRADIENT WILL GENERALLY DOMINATE FOR THE REST OF
THIS WEEK...RESULTING IN WINDS UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
512 AM EDT TUE SEP 25 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 511 AM EDT TUE SEP 25 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW A TROF OVER SE
CANADA INTO THE NE CONUS. REINFORCING SHORTWAVE TROF DROPPED THRU
THE UPPER LAKES LAST EVENING...BRINGING ANOTHER PUSH OF COOLER AIR
INTO THE AREA. AFTER THE SURGE OF WARMER AIR YESTERDAY ON GUSTY W/SW
WINDS AHEAD OF SHORTWAVE...850MB TEMPS ARE BACK DOWN TO 0C ACROSS
LAKE SUPERIOR...BUT ARE STILL AROUND 5C OVER THE FAR SCNTRL FCST
AREA PER LATEST RUC ANALYSIS. RELATIVELY DRY AIR HAS ALSO FOLLOWED
SHORTWAVE INTO UPPER MI...BUT UPSTREAM CWPL SOUNDING AT 00Z SHOWED
NEAR SATURATION FROM ABOUT 900MB TO 700MB. ALTHOUGH RECENT SATELLITE
IMAGERY SHOWS A SLIGHT INCREASE IN LAKE EFFECT CLOUDS...COVERAGE IS
STILL VERY LIMITED. NO SHRA ARE EVIDENT. TO THE N...CANADIAN RADARS
SHOW SOME -SHRA OFF LAKE NIPIGON.
MAIN CONCERN IN THE SHORT TERM WILL MAINLY BE LAKE EFFECT SHRA
POTENTIAL. SHORTWAVE UPSTREAM IN ERN MANITOBA AND FOLLOWING PIECE OF
ENERGY A LITTLE FARTHER N WILL BE ENHANCING FACTORS FOR SHRA
DEVELOPMENT. WITH DEEP LAYER FORCING PER QVECTORS SPREADING OVER THE
AREA TODAY ALONG WITH AN INCREASE IN LOW-LEVEL MOISTURE...EXPECT SOME
-SHRA DEVELOPMENT...BUT THE DISRUPTION OF LAKE EFFECT PROCESSES BY
DAYTIME HEATING WILL BE A SIGNIFICANT NEGATIVE FACTOR. PERIODIC
HEAVY WAVE ACTION ON LAKE SUPERIOR OVER THE LAST WEEK OR SO HAS
RESULTED IN MID LAKE WATER TEMPS FALLING TO 10-13C WHILE READINGS
AROUND 15-16C ARE PROBABLY STILL MORE COMMON OVER THE SRN PORTION OF
THE LAKE. SO OVERWATER INSTABILITY IS A LITTLE MORE MARGINAL...
ESPECIALLY FOR THE MORE DISRUPTIVE DAYTIME HRS. AT THIS POINT...
NOTHING MORE THAN SCHC POPS APPEAR WARRANTED...MAINLY OVER THE
NCNTRL FCST AREA AS DRIER AIR TO THE W SHOULD PREVENT ANY SHRA
DEVELOPMENT OFF WRN LAKE SUPERIOR.
SHRA COVERAGE SHOULD TEND TO INCREASE LATE TONIGHT AS 850MB TEMPS
FALL TOWARD -2C AND A WEAK SFC TROF DROPS S ACROSS THE LAKE IN
ASSOCIATION WITH SHORTWAVE. TIMING OF TROF WILL ALSO COINCIDE WITH
THE MORE FAVORABLE MIN OF THE DIURNAL CYCLE. THUS...HAVE POPS
INCREASING TO CHC OVER THE NCNTRL/NE FCST AREA LATE TONIGHT. LEFT
THE W DRY DUE TO LARGER AREA OF COOLER WATER OVER THE WRN LAKE AND
DUE TO DEEP LAYER QVECTOR DIVERGENCE DOMINATING. SOME OF THE HIGH
RES MODEL GUIDANCE INDICATES -SHRA WILL OCCUR OVER THE W...SO WILL
NEED TO REEXAMINE POTENTIAL AGAIN IN LATER FCSTS. IN THE INTERIOR W
TONIGHT...THERE SHOULD BE A SUFFICIENT LACK OF CLOUDS TO ALLOW TEMPS
TO FALL TO AROUND 30F...RESULTING IN FROST DEVELOPMENT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 511 AM EDT TUE SEP 25 2012
SHORTWAVE WILL BE EXITING THE CWA TO THE SE AT THE START OF THE
PERIOD...SETTING UP A PERIOD OF SPLIT FLOW THROUGH THE END OF THE
WEEK. THE NRN STREAM WILL BE SET IN CANADA...WHILE THE SRN STREAM
WILL BE OVER THE SRN HALF OF THE CONUS. THIS WILL ALLOW FOR HIGH
PRESSURE TO SETTLE IN AND PRODUCE A FAIRLY DRY LONG TERM PERIOD.
FORCING FROM THE SHORTWAVE...COMBINING WITH A POCKET OF LLVL
MOISTURE...SHOULD ALLOW SHOWERS TO BE ONGOING OVER SCNTRL/ERN LAKE
SUPERIOR AND ERN UPPER MI. THESE SHOWERS WILL BE AIDED BY ENHANCED
LLVL CONVERGENCE AND INCREASED LK INSTABILITY WITH H850 TEMPS AROUND
1C. THE SHOWERS SHOULD CONTINUE THROUGH MUCH OF THE MORNING...BUT
HIGH PRESSURE BUILDING IN AND THE QUICKLY EXITING SHORTWAVE/MOISTURE
SHOULD BRING A DIMINISHING TREND IN THE EARLY AFTERNOON.
ANTICYCLONIC FLOW INCREASING THROUGH THE DAY AND DRYING ALOFT
LOWERING THE CAPPING INVERSION WILL ALSO DIMINISH THE SHOWERS. WITH
THE CLOUDS IN PLACE FOR MUCH OF THE DAY...EXPECT HIGHS TO ONLY RISE
INTO THE 50S...WITH THE COOLEST VALUES OVER THE N WHERE THE CLOUD
COVER WILL BE THE THICKEST.
THIS HIGH WILL REMAIN IN PLACE THROUGH AT LEAST THURS NIGHT AND LEAD
TO DRY WX OVER UPPER MI. EXPECT A COLD NIGHT WED NIGHT WITH THE HIGH
BEING NEARLY OVERHEAD. PWATS AROUND 50 PERCENT OF NORMAL AND CLEAR
SKIES WILL PROMOTE RADIATIONAL COOLING AND EXPECT LOWS IN THE UPPER
20S AND LOWER 30S OVER MOST INTERIOR LOCATIONS. THIS WILL PRODUCE
ANOTHER DECENT FROST/FREEZE ACROSS THE AREA. SINCE MOST INTERIOR
LOCATIONS HAVE SEEN A FROST OR FREEZE ALREADY THIS MONTH...OUR
ADVISORY/WARNING HEADLINES HAVE ENDED...BUT WILL CONTINUE TO MENTION
FROST DURING THE TRANSITION PERIOD.
OTHER THAN SOME DIURNAL CU OVER THE SE HALF OF UPPER MI THURS
AFTN...EXPECT MOSTLY CLEAR SKIES TO CONTINUE ON THURS AND INTO FRI.
GRADUALLY WARMING H850 TEMPS WILL LEAD TO HIGHS RISING INTO THE 60S
FOR THURS/FRI...WHICH IS BACK TO NORMAL.
THE GREATEST UNCERTAINTY FOR THE LONG TERM FORECAST COMES WITH THE
SHORTWAVE THAT MOVES THROUGH THE NRN STREAM IN ONTARIO ON FRI. THIS
WILL DRAG A WEAK COLD FRONT ACROSS UPPER MI LATE THURS NIGHT AND
INTO FRI...BUT WILL ONLY CAUSE A SLIGHT WINDSHIFT.
THEN...DETERMINISTIC AND ENSEMBLE MODELS ARE STARTING TO TREND
TOWARDS THE SHORTWAVE BECOMING CLOSED/CUT OFF OVER FAR SE ONTARIO ON
SAT AND SLOWLY DRIFTING SSW INTO THE GREAT LKS. CONFIDENCE IS
INCREASING ON THIS OCCURRENCE...BUT THE LOCATION VARIES DEPENDING
ON THE MODEL. AT THIS POINT...WITH MOISTURE NOT EXPECTED TO BE TOO
FAR FROM THE SHORTWAVE WHILE MOVING THROUGH ONTARIO...DON/T THINK
THERE WILL BE MUCH MOISTURE TO WORK WITH WHEN THE TROUGH CUTS OFF.
THEREFORE...WILL CONTINUE TO FOLLOW A DRY FORECAST FOR THE WEEKEND
AS THE GENERAL CONSENSUS OF THE MODELS HAS THE UPPER LOW CENTERED
OVER LK HURON AND WEAK HIGH PRESSURE OVER THE CWA. RIGHT NOW
TEMPERATURES APPEAR TO BE SEASONABLE FOR THE END OF THE WORK WEEK
AND INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 138 AM EDT TUE SEP 25 2012
VFR CONDITIONS ARE EXPECTED TO GIVE WAY TO SOME MVFR CIGS AS
LOW-LEVEL MOISTURE/MVFR CIGS CURRENTLY ACROSS NRN MANITOBA/NRN
ONTARIO SETTLES INTO THE UPPER LAKES. WITH MOISTURE AND INCREASING
OVER WATER INSTABILITY...MVFR CIGS WERE INCLUDED AT KSAW LATE. MORE
DIVERGENT LOW-LEVEL FLOW SHOULD KEEP KIWD AND KCMX VFR THRU THE END
OF THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 AM EDT TUE SEP 25 2012
HIGH PRES/WEAK PRES GRADIENT WILL GENERALLY DOMINATE FOR THE REST OF
THIS WEEK...RESULTING IN WINDS UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1156 PM CDT MON SEP 24 2012
.UPDATE...
ISSUED AT 822 PM CDT MON SEP 24 2012
LATEST RUC AND HRRR CONTINUE TO SUPPORT CATEGORICAL POPS ALONG AND
NORTH OF INTERSTATE 70 BETWEEN 06Z AND 12Z. CONVECTIVE INITIATION
SHOULD OCCUR ACROSS NORTHWEST MISSOURI BETWEEN 04Z AND 06Z AND
QUICKLY GROW UPSCALE INTO A CONVECTIVE COMPLEX THAT WILL MOVE EAST
ACROSS THE NORTHERN HALF OF MISSOURI INTO CENTRAL/SOUTHWEST
ILLINOIS. NO MAJOR CHANGES MADE TO THE FORECAST.
CVKING
&&
.SHORT TERM...
ISSUED AT 251 PM CDT MON SEP 24 2012
(TONIGHT)
WHAT LOOKS TO BE A RATHER ACTIVE/WET WORK WEEK SHOULD BEGIN TONIGHT.
STRONG WARM/MOIST ADVECTION WILL COMMENCE OVER THE AREA AFTER DUSK
AS A 45-50 KT SOUTHWESTERLY LLJ DEVELOPS. UPPER LEVEL FORCING
MECHANISMS IN THE FORM OF DCPVA DOWNSTREAM OF A 500-HPA TROUGH AND
RIGHT ENTRANCE REGION OF A 60-KT UPPER LEVEL JET WILL HELP PROVIDE
UVM ON THE SYNOPTIC SCALE. THE COLLOCATION OF THESE AFOREMENTIONED
FORCING MECHANISMS LOOKS TO TAKE PLACE ALONG AND JUST NORTH OF THE
INTERSTATE 70 CORRIDOR IN MISSOURI AND I-64 CORRIDOR IN ILLINOIS.
HAVE PLACED CATEGORICAL POPS LATE TONIGHT IN THIS REGION TO ACCOUNT
FOR THIS. AFTER INVESTIGATING NWP SOUNDINGS...CONVECTION SHOULD BE
ROOTED ABOVE A STABLE NOCTURNAL INVERSION WITH SOME OF THE STRONGER
STORMS CAPABLE OF PRODUCING LARGE HAIL GIVEN STEEP MIDLEVEL LAPSE
RATES AND AMPLE ELEVATED CAPE WITHIN HAIL GROWTH ZONE.
FOLLOWED 0900 UTC SREF/1200 UTC NAM FAIRLY CLOSELY FOR POPS/QPF. FOR
LOW TEMPERATURES...DID NOT DEVIATE SUBSTANTIALLY FROM MOS OUTPUT.
DID GO A BIT ABOVE GUIDANCE IN FAR NORTHERN/SOUTHERN CWA WHERE
LOWEST POPS/QPF ARE LOCATED. ALSO TRIED MY BEST TO CAPTURE A W/E
ORIENTED AXIS OF COOLER LOW TEMPERATURES COLLOCATED WITH AXIS OF
HEAVIEST RAINFALL AND HIGHEST POPS TO ACCOUNT FOR POTENTIAL
EVAPORATIVE COOLING.
GOSSELIN
&&
.LONG TERM...
ISSUED AT 251 PM CDT MON SEP 24 2012
(TOMORROW THROUGH SUNDAY)
THE PRIMARY FCST ISSUE OVER THE NEXT FEW DAYS IS PCPN CHCS. THIS IS
A COMPLICATED FCST BECAUSE PCPN CHCS FOR EACH DAY WILL DEPEND TO
SOME EXTENT ON WHAT WILL HAVE HAPPENED THE PREVIOUS NIGHT...AND
THOSE KINDS OF MESOSCALE DETAILS ARE DIFFICULT TO PIN DOWN
ACCURATELY MORE THAN A FEW HOURS IN ADVANCE. THE BEST WAY TO
INTERPRET THE WIDESPREAD CHC POPS IN THIS FCST PCKG IS THAT PCPN IS
POSSIBLE ALMOST ANYWHERE EVEN THOUGH IT PROBABLY WILL NOT RAIN
EVERYWHERE.
ELEVATED CONVECTION IS EXPECTED TO BE ONGOING ACROSS PARTS OF THE
CWA AT 12Z TUE DUE TO A STRONG LLJ IMPINGING ON A N-S ORIENTED WMFNT
LOCATED WEST OF THE CWA AND AIDED BY LARGE SCALE ASCENT AHEAD OF
A WEAK SHORTWAVE. TSRA COVERAGE SHOULD DIMINISH THROUGH THE
MORNING ONCE THE LLJ BEGINS TO WEAKEN. A SFC LOW PRESSURE CENTER
RIDING ALONG THE QUASISTATIONARY FNT IN KS WILL MOVE INTO CENTRAL
MO AND PUSH THE WMFNT THROUGH THE CWA BY LATE TUE AFTN...KEEPING
THE QUASISTATIONARY BDRY IN PLACE ACROSS SRN IA OR NRN MO.
ALTHOUGH THIS WILL PLACE THE CWA IN THE WARM SECTOR FOR THE
AFTN...RESIDUAL CLOUDINESS FM OVERNIGHT CONVECTION SHOULD LIMIT
WIDESPREAD DESTABILIZATION ALTHOUGH ISO-SCT TSRA COULD STILL
DEVELOP ON TUE AFTN IF THERE ARE POCKETS OF CLRG...ESPECIALLY
GIVEN MODEL FCSTS OF FAVORABLE H7-H5 LAPSE RATES SPREADING ACROSS
THE AREA.
THE KEY ISSUE MODULATING PCPN CHCS BEYOND TUE AFTN WILL BE THE
LOCATION OF THE QUASISTATIONARY BDRY MENTIONED ABOVE. THERE WILL NOT
BE MUCH IN THE WAY OF UPPER LEVEL SUPPORT TO INFLUENCE ITS POSITION
THIS WEEK. A HIGH PRESSURE CENTER WILL BE SLIDING SEWD FM CANADA
INTO THE GRTLKS FM TUE THROUGH THU AND THE CIRCULATION AROUND THAT
SFC HIGH COMBINED WITH THE CIRCULATIONS AROUND PERIODIC SFC LOWS
WILL ACT TO SHARPEN THE TEMPERATURE CONTRAST ACROSS THE
QUASISTATIONARY BDRY AND LIMIT ITS NWD PROGRESS. AT THE SAME
TIME...CONVECTIVE INFLUENCES MAY END UP PUSHING THE EFFECTIVE FRONT
EVEN FARTHER SOUTH THAN INDICATED BY THE MODELS. FINALLY...THE
STRENGTH OF THE HIGH PRESSURE CENTER WILL ALSO INFLUENCE THE INITIAL
LOCATION OF THE BDRY.
ATTM MODELS ARE IN GOOD AGREEMENT THAT THE BDRY WILL BE LOCATED
RIGHT ALONG THE MO/IA BORDER FOR MOST OF TUE NIGHT. A BROAD SWLY LLJ
THEN DVLPS OVERNIGHT ALONG WITH PW VALUES OF 1.3 TO 1.5 INCHES WHICH
IS AROUND THE 75TH PERCENTILE FOR SEPT IN THIS PART OF THE COUNTRY.
CONCEPTUAL MODELS SUPPORT THE IDEA THAT A QUASISTATIONARY E-W BDRY
WITH A NOCTURNAL LLJ NEARLY PARALLEL TO IT AND ON ITS WARM SIDE
WOULD LEAD TO AN ELONGATED AREA OF PCPN VERY CLOSE TO THE BDRY.
GFS/NAM ALSO SUPPORT THIS IDEA WITH CORFIDI VECTORS POINTED
UPSTREAM...SUGGESTING THAT NEW CONVECTION WILL CONTINUOUSLY DVLP AND
MOVE ENEWD WITHIN THE OVERALL BAND OF PCPN. PCPN SHOULD CONTINUE
THROUGH AT LEAST PART OF WED MORNING UNTIL THE LLJ WEAKENS.
MODELS BEGIN TO DIFFER ON THE LOCATION OF THE BDRY BY WED/THU AND IT
IS ENTIRELY POSSIBLE THAT THE EFFECTIVE BDRY MAY HAVE BEEN PUSHED
FARTHER SOUTH THAN THE MODELS SUGGEST DUE TO OUTFLOW BDRYS FROM
OVERNIGHT CONVECTION ON THE PREVIOUS COUPLE OF NIGHTS. THERE IS
LITTLE EVIDENCE OF A LLJ ON WED NIGHT OR THU NIGHT HOWEVER THE BDRY
WILL STILL BE PRESENT AND FAVORABLY POSITIONED BENEATH THE LEFT EXIT
REGION OF A H25 JET ON THU NIGHT AND FRI NIGHT. ULTIMATELY...SCT
PCPN IS USUALLY A FAIR BET WITH A QUASISTATIONARY BDRY ACROSS THE
AREA AND EVEN A HINT OF FORCING...THEREFORE WILL CONTINUE WITH
SCHC-CHC POPS THROUGH AT LEAST FRI. BEYOND FRI...MODELS SHOW THAT
THE QUASISTATIONARY FNT WILL BE PUSHED SWD AS A CDFNT BEFORE
STALLING SOMEWHERE IN THE REGION BY THE WEEKEND...BRINGING COOLER
TEMPERATURES TO PARTS OF MO/IL LATE IN THE FCST PD.
KANOFSKY
&&
.AVIATION...
ISSUED AT 1148 PM CDT MON SEP 24 2012
AS THE LLJ INCREASES THRU TONIGHT...EXPECT TSRA TO DEVELOP AHEAD OF
THE SFC LOW ACROSS WRN AND CENTRAL MO AND SPREAD EWD OVER THE NEXT
FEW HOURS. TSRA SHUD TRAVEL ALONG AND JUST N OF I70. BELIEVE PREV TAFS
HAVE A GOOD HANDLE ON THIS TREND AND FEW CHANGES WERE MADE. TSRA
SHUD MOVE OUT OF REGION/DIMINISH TUES MORNING. BELIEVE TERMINALS
WILL BE DRY TUES INTO THE LATE AFTERNOON/EVENING HOURS. TSRA SHUD
DEVELOP ALONG THE STATIONARY SFC FNT...BUT EXACT LOCATION IS
QUESTIONABLE AND WILL LIKELY DEPEND SOMEWHAT ON CONVECTION THIS
MORNING.
OTHERWISE...WINDS WILL BECOME SWLY S OF THE SFC FNT WITH GUSTS TO
20 KTS AT ALL TERMINALS EXCEPT FOR UIN. GUSTS MAY BE HIGHER
ESPECIALLY IN THE MORNING AS MIXING BEGINS. THESE GUSTS WILL
DIMINISH TUES EVENING WITH SUNSET. THE SFC FNT MAY MOVE S OF
COU/CPS/SUS TUES EVE...BUT WINDS MAY BE ERRATIC DUE TO TSRA.
SPECIFICS FOR KSTL...FEW CHANGES TO THE PREV TAF. STILL EXPECT
TSRA TO IMPACT TERMINAL LATE TONIGHT THRU DAWN TUES. EXPECT TSRA
TO DIMINISH/MOVE E OF TERMINAL SHORTLY AFTER SUNRISE. REGION SHUD
REMAIN DRY THRU MUCH OF THE DAY WITH THE NEXT ROUND OF TSRA
INITIATING TUES LATE AFTERNOON/EVENING ALONG STATIONARY SFC FNT.
BELIEVE BEST CHANCES FOR TSRA TUES EVE. WILL LET FUTURE UPDATES
HANDLE THIS ROUND OF PRECIP AS LOCATION OF THE SFC FNT WILL
DETERMINE TIMING AND IMPACT ON TERMINAL. OTHERWISE...WINDS WILL BECOME
SWLY S OF THE SFC FNT TUES MORNING WITH GUSTS TO AROUND 20 KTS.
WINDS WILL DIMINISH WITH SUNSET.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1243 PM CDT TUE SEP 25 2012
.UPDATE...
.DISCUSSION...
ISOLATED SHOWERS CONTINUE TO MOVE EAST ALONG AND SOUTH OF NEBRASKA
HIGHWAY 2. THE FCST HAS BEEN UPDATED AND ALLOWS THESE SHOWERS TO
DRIFT EAST THIS AFTERNOON. GIVEN THE ELEVATED MIXED LAYER
CAPE AND WEAK WIND FIELDS AT ALL LEVELS...THUNDER WILL CONTINUE IN THE
FCST BUT JUST A RUMBLE OR TWO SHOULD BE EXPECTED.
&&
.AVIATION...
VFR IS EXPECTED ALL AREAS THIS AFTERNOON THROUGH WEDNESDAY
MORNING.
A WEAK UPPER LEVEL DISTURBANCE WILL DRIFT EAST THIS AFTERNOON AND
THIS EVENING PRODUCING ISOLATED SHRA AND PERHAPS A THUNDERSTORM OR
TWO. NO LIGHTNING HAS BEEN DETECTED THUS FAR. CIGS SHOULD OPERATE
AT BKN070 OVC150 IN THE SHRA/TSTM ACTIVITY.
&&
.PREV DISCUSSION... /ISSUED 1003 AM CDT TUE SEP 25 2012/
UPDATE...
DISCUSSION...
UPDATE TO THE FORECAST FOR THE ISOLATED SHOWERS DEVELOPING IN
CONJUNCTION WITH A WEAK UPPER LEVEL DISTURBANCE ACROSS WRN
NEBRASKA. LAPSE RATES ARE STEEP AT KDNR AND KLBF SO WE MIGHT SEE
SOME ISOLATED THUNDER. THE RUC SHOWS NO QPF WHILE THE HRRR IS
PUMPING OUT LOTS OF RADAR RETURNS BUT LITTLE ACCUMULATION.
THINKING IS THAT THE RADAR RETURNS WILL WEAKEN AS THEY ENCOUNTER DRY
AIR FARTHER EAST AND DISSIPATE BEFORE REACHING HIGHWAY 83. WE
WILL SEE LATER THIS MORNING.
PREV DISCUSSION... /ISSUED 650 AM CDT TUE SEP 25 2012/
AVIATION...
FOR THE KLBF AND KVTN TERMINALS 12Z TAFS.
UPPER LEVEL LOW PRESSURE WILL MOVE INTO THE CENTRAL ROCKIES TODAY.
THIS FEATURE WILL SPREAD ABUNDANT HIGH CLOUDINESS TO WESTERN NEBRASKA
WITH CIGS RANGING FROM 10000 TO 15000 FT AGL. ONLY THIN HIGH
CLOUDINESS AOA 20000 FT IS FORECAST ACROSS NORTHERN NEBRASKA.
WINDS OVER THE NEXT 24 HOURS WILL BE LIGHT AND VARIABLE THROUGH
17Z. THEREAFTER...EXPECT LIGHT EASTERLY WINDS AT UNDER 10 KTS
THROUGH 06Z WEDNESDAY.
PREV DISCUSSION... /ISSUED 415 AM CDT TUE SEP 25 2012/
DISCUSSION...
PRIMARY FORECAST CONCERNS FOR THIS FORECAST CYCLE INCLUDE
PRECIPITATION CHANCES THROUGH SATURDAY AND TEMPERATURES THROUGH
THE SAME TIME PERIOD
WATER VAPOR IMAGERY THIS MORNING SHOWED LONGWAVE TROUGH OVER THE
NORTHEAST QUARTER OF THE COUNTRY...WITH THE UPPER LOW CENTERED
OVER HUDSON BAY. A SECOND LONGWAVE TROUGH WAS SEEN OVER THE
NORTHERN PACIFIC OCEAN...WITH A FAIRLY STRONG SHORTWAVE TROUGH
JUST DOWNSTREAM OF THE PACIFIC TROUGH INTO WESTERN CANADA AND THE
PACIFIC NORTHWEST. RIDGING WAS IN PLACE BETWEEN THESE
SYSTEMS...WHICH EXTENDED INTO NORTH CENTRAL CANADA. THE GENERAL
FLOW IMPACTING THE LOCAL AREAS WAS NORTHWEST FLOW...WHILE PICKING
OUT SEVERAL SHORTWAVE TROUGHS. THE FIRST WAS OVER EASTERN SOUTH
DAKOTA....WHILE A SECOND WAS OVER SOUTHERN SASKATCHEWAN AND
ANOTHER OVER EASTERN MANITOBA. THERE WAS ALSO SOME SOUTHERN STREAM
INFLUENCE AS AN UPPER LEVEL LOW CENTERED OVER THE NEVADA/UTAH
BORDER ATTEMPTED TO HELP SOME WEAK UPPER LEVEL RIDGING TO BUILD
INTO EASTERN COLORADO THIS MORNING. AHEAD OF THE RIDGING WAS A
WEAK MID LEVEL IMPULSE OVER NORTHERN KANSAS WHICH DID HELP THE
DEVELOPMENT OF SOME SHOWERS FROM SOUTHWEST NEBRASKA INTO NORTHERN
KANSAS THIS MORNING. THE NEXT IMPULSE OF ENERGY SEEN WITH THE
UPPER LOW WAS MOVING ACROSS SOUTHERN COLORADO THIS MORNING.
AT THE SURFACE HIGH PRESSURE HAD SETTLED IN OVER NORTHWEST
NEBRASKA...WHICH HAS ALLOWED TEMPERATURES TO DROP SIGNIFICANTLY
WITH READINGS CURRENTLY IN THE LOW 40S. OTHERWISE...A STATIONARY
FRONT WAS SEEN FROM EASTERN WYOMING INTO EASTERN COLORADO...WHILE
ANOTHER COLD FRONT WAS OBSERVED ACROSS SOUTHERN MINNESOTA AND INTO
CENTRAL SOUTH DAKOTA....BEING DRIVEN BY THE SHORTWAVE OVER SOUTH
DAKOTA.
GETTING SOME ECHOES ON RADAR OVER SOUTHERN NEBRASKA THIS MORNING
WITH THE WAVE MOVING SOUTH OF THE AREA THIS MORNING. OBSERVATION
SITES WERE NOT REGISTERING ANY CLOUDS BELOW 10K FEET ONLY A TRACE
OF RAINFALL HAD BEEN REPORTED AT A FEW SITES WITH THESE PASSING
SHOWERS. THIS WOULD CORRELATE WELL WITH THE OBSERVED 25.00Z
SOUNDING FROM LBF WHICH SHOWED VERY DRY AIR BELOW 600MB TO
EVAPORATE AY RAINFALL BEFORE HITTING THE SURFACE.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
THE ACTIVITY ON RADAR SHOULD DECREASE THIS MORNING AS THE
SHORTWAVE OVER NORTHERN KANSAS PUSHES EAST. DID INCLUDE SPRINKLES
IN THE FORECAST FOR THE SOUTHWEST COUNTIES WITH THESE SHOWERS BUT
THEY SHOULD END BY NOON.
TODAY...THE SHORTWAVE OVER SOUTHERN COLORADO WILL MOVE INTO EASTERN
COLORADO...BUT THEN GETS CAUGHT IN THE SOUTHWEST FLOW WHICH KEEPS
THE MAJORITY OF THE ENERGY ACROSS KANSAS. COULD SEE FURTHER
DEVELOPMENT OF HIGH BASED SHOWERS AND ISOLATED THUNDERSTORMS
ASSOCIATED WITH THIS ENERGY...BUT EXPECT IT TO STAY ACROSS THE FAR
WESTERN PARTS OF THE FORECAST AREA. WITH A GOOD AMOUNT OF MOISTURE
IN THE MID AND HIGH LEVELS ASSOCIATED WITH THE UPPER LOW WILL
CONTINUE TO SEE PARTLY TO MOSTLY CLOUDY SKIES ACROSS THE SOUTHWEST
HALF OF NEBRASKA TODAY. THIS WILL BE THE TREND FOR THE NEXT
SEVERAL DAYS AS WELL...WHILE THE UPPER LOW STAYS OFF TO THE WEST
OF THE FORECAST AREA. TEMPERATURES ALOFT WARM SLIGHTLY FROM
YESTERDAY SO EXPECT HIGHS A FEW DEGREES WARMER TODAY DESPITE THE
CLOUD COVER. THE WARMEST READINGS SHOULD BE OVER NORTH CENTRAL
NEBRASKA WHERE SUNSHINE SHOULD BE PLENTIFUL.
FOR WEDNESDAY...THE MAIN UPPER LOW PROGRESSES EAST INTO COLORADO.
AS SAID ABOVE...MOISTURE WILL CONTINUE TO BE PULLED INTO THE
REGION AHEAD OF THE SYSTEM...BUT MAINLY IN THE MID LEVELS /ABOVE
700MB/. MEANWHILE...DRY HIGH PRESSURE WILL REMAIN IN PLACE OVER
THE UPPER MISSISSIPPI RIVER VALLEY REGION. EASTERLY FLOW WILL
CONTINUE TO PULL DRY AIR INTO NEBRASKA IN THE LOWER LEVELS TO KEEP
THE AIR VERY DRY IN THE BOUNDARY LAYER. ALTHOUGH...SHOWERS MAY
DEVELOP ON WEDNESDAY AS INCREASED LIFT ASSOCIATED WITH THE UPPER
LEVEL LOW MOVES INTO WESTERN NEBRASKA...THE VERY DRY AIR IN THE
BOUNDARY LAYER WILL PROHIBIT THE AREA FROM SEEING A GOOD CHANCE
FOR MEASURABLE RAINFALL. WILL NOT CHANGE MUCH FROM PREVIOUS
FORECAST...KEEPING ONLY A SLIGHT CHANCE FOR MEASURABLE RAIN
WEDNESDAY.
THE CLOSED LOW WILL MIGRATE EAST AND BECOME AN OPEN WAVE THURSDAY
AND THURSDAY NIGHT. THE MAIN CIRCULATION LOOKS TO TRACK ALONG THE
NEBRASKA KANSAS BORDER...WHICH WILL BRING THE HIGHEST CHANCE FOR
RAIN THROUGH THESE PERIODS. IN ADDITION...THE SHORTWAVE TROUGH
CURRENTLY OVER THE PACIFIC NORTHWEST WILL TRACK INTO THE NORTHERN
PLAINS WHICH WILL DRIVE A PACIFIC COLD FRONT TOWARDS THE AREA. IN
ADDITION TO THE RAIN CHANCES WITH THE UPPER LOW...THERE COULD BE
SOME DEVELOPMENT OF THUNDERSTORMS AHEAD OF THIS COLD FRONT WHICH
WOULD MAINLY IMPACT PARTS OF THE PANHANDLE AND WESTERN SANDHILLS.
AGAIN...DRY AIR WILL BE IN PLACE IN THE LOWER LEVELS SO DON/T HAVE
A LOT OF CONFIDENCE ON THE COVERAGE OF ANY RAIN. SO HAVE CONTINUED
THE LOWER CHANCES THROUGH THIS TIME PERIOD.
LONG TERM...FRIDAY THROUGH MONDAY
MODEL SOLUTIONS DIVERGE FURTHER WITH TIME GOING INTO THE WEEKEND.
THE UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS MENTIONED ABOVE
WILL CONTINUE TO HAVE SOME IMPACT ON THE FORECAST AREA THROUGH THE
FIRST PART OF THE WEEKEND. THE MAIN ISSUES WITH HOW THIS
PROGRESSES IS FROM HOW THE UPPER LOW OVER THE GREAT LAKES BEHAVES. THERE
ARE INDICATIONS THAT IT WILL NOT SEE MUCH MOVEMENT /IF THE ECMWF
VERIFIES KEEPING THE UPPER LOW OVER THE GREAT LAKES/FROM THURSDAY
NIGHT THROUGH SATURDAY...KEEPING THE COLD FRONT ACROSS THE HIGH
PLAINS. THIS WOULD LEAD TO POTENTIAL FOR STORMS AND SHOWERS BOTH
FRIDAY AND SATURDAY. ON THE OTHER HAND...IF THE NORTHEAST SYSTEM
IS MORE PROGRESSIVE WHICH WOULD MEAN A DRY FORECAST. WITH LOW
CONFIDENCE...KEPT THE FORECAST DRY THIS CYCLE.
FIRE WEATHER...
SEVERAL DAYS WILL SEE LOW RELATIVE HUMIDITY IN THE
AFTERNOON...HOWEVER WINDS THESE DAYS ARE NOT FORECAST TO BE
PARTICULARLY STRONG. CURRENTLY WEDNESDAY AND THURSDAY LOOK TO SEE
THE STRONGEST WINDS /WITH GUSTS TO 20 MPH/...HOWEVER RELATIVE
HUMIDITY BOTH DAYS SHOULD BOTTOM OUT AROUND 25 PERCENT. AT THIS
POINT DO NOT EXPECT THE NEED FOR ANY FIRE WEATHER HEADLINES IN THE
NEXT WEEK.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...POWER
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1003 AM CDT TUE SEP 25 2012
.UPDATE...
.DISCUSSION...
UPDATE TO THE FORECAST FOR THE ISOLATED SHOWERS DEVELOPING IN
CONJUNCTION WITH A WEAK UPPER LEVEL DISTURBANCE ACROSS WRN
NEBRASKA. LAPSE RATES ARE STEEP AT KDNR AND KLBF SO WE MIGHT SEE
SOME ISOLATED THUNDER. THE RUC SHOWS NO QPF WHILE THE HRRR IS
PUMPING OUT LOTS OF RADAR RETURNS BUT LITTLE ACCUMULATION.
THINKING IS THAT THE RADAR RETURNS WILL WEAKEN AS THEY ENCOUNTER DRY
AIR FARTHER EAST AND DISSIPATE BEFORE REACHING HIGHWAY 83. WE
WILL SEE LATER THIS MORNING.
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT TUE SEP 25 2012/
AVIATION...
FOR THE KLBF AND KVTN TERMINALS 12Z TAFS.
UPPER LEVEL LOW PRESSURE WILL MOVE INTO THE CENTRAL ROCKIES TODAY.
THIS FEATURE WILL SPREAD ABUNDANT HIGH CLOUDINESS TO WESTERN NEBRASKA
WITH CIGS RANGING FROM 10000 TO 15000 FT AGL. ONLY THIN HIGH
CLOUDINESS AOA 20000 FT IS FORECAST ACROSS NORTHERN NEBRASKA.
WINDS OVER THE NEXT 24 HOURS WILL BE LIGHT AND VARIABLE THROUGH
17Z. THEREAFTER...EXPECT LIGHT EASTERLY WINDS AT UNDER 10 KTS
THROUGH 06Z WEDNESDAY.
PREV DISCUSSION... /ISSUED 415 AM CDT TUE SEP 25 2012/
DISCUSSION...
PRIMARY FORECAST CONCERNS FOR THIS FORECAST CYCLE INCLUDE
PRECIPITATION CHANCES THROUGH SATURDAY AND TEMPERATURES THROUGH
THE SAME TIME PERIOD
WATER VAPOR IMAGERY THIS MORNING SHOWED LONGWAVE TROUGH OVER THE
NORTHEAST QUARTER OF THE COUNTRY...WITH THE UPPER LOW CENTERED
OVER HUDSON BAY. A SECOND LONGWAVE TROUGH WAS SEEN OVER THE
NORTHERN PACIFIC OCEAN...WITH A FAIRLY STRONG SHORTWAVE TROUGH
JUST DOWNSTREAM OF THE PACIFIC TROUGH INTO WESTERN CANADA AND THE
PACIFIC NORTHWEST. RIDGING WAS IN PLACE BETWEEN THESE
SYSTEMS...WHICH EXTENDED INTO NORTH CENTRAL CANADA. THE GENERAL
FLOW IMPACTING THE LOCAL AREAS WAS NORTHWEST FLOW...WHILE PICKING
OUT SEVERAL SHORTWAVE TROUGHS. THE FIRST WAS OVER EASTERN SOUTH
DAKOTA....WHILE A SECOND WAS OVER SOUTHERN SASKATCHEWAN AND
ANOTHER OVER EASTERN MANITOBA. THERE WAS ALSO SOME SOUTHERN STREAM
INFLUENCE AS AN UPPER LEVEL LOW CENTERED OVER THE NEVADA/UTAH
BORDER ATTEMPTED TO HELP SOME WEAK UPPER LEVEL RIDGING TO BUILD
INTO EASTERN COLORADO THIS MORNING. AHEAD OF THE RIDGING WAS A
WEAK MID LEVEL IMPULSE OVER NORTHERN KANSAS WHICH DID HELP THE
DEVELOPMENT OF SOME SHOWERS FROM SOUTHWEST NEBRASKA INTO NORTHERN
KANSAS THIS MORNING. THE NEXT IMPULSE OF ENERGY SEEN WITH THE
UPPER LOW WAS MOVING ACROSS SOUTHERN COLORADO THIS MORNING.
AT THE SURFACE HIGH PRESSURE HAD SETTLED IN OVER NORTHWEST
NEBRASKA...WHICH HAS ALLOWED TEMPERATURES TO DROP SIGNIFICANTLY
WITH READINGS CURRENTLY IN THE LOW 40S. OTHERWISE...A STATIONARY
FRONT WAS SEEN FROM EASTERN WYOMING INTO EASTERN COLORADO...WHILE
ANOTHER COLD FRONT WAS OBSERVED ACROSS SOUTHERN MINNESOTA AND INTO
CENTRAL SOUTH DAKOTA....BEING DRIVEN BY THE SHORTWAVE OVER SOUTH
DAKOTA.
GETTING SOME ECHOES ON RADAR OVER SOUTHERN NEBRASKA THIS MORNING
WITH THE WAVE MOVING SOUTH OF THE AREA THIS MORNING. OBSERVATION
SITES WERE NOT REGISTERING ANY CLOUDS BELOW 10K FEET ONLY A TRACE
OF RAINFALL HAD BEEN REPORTED AT A FEW SITES WITH THESE PASSING
SHOWERS. THIS WOULD CORRELATE WELL WITH THE OBSERVED 25.00Z
SOUNDING FROM LBF WHICH SHOWED VERY DRY AIR BELOW 600MB TO
EVAPORATE AY RAINFALL BEFORE HITTING THE SURFACE.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
THE ACTIVITY ON RADAR SHOULD DECREASE THIS MORNING AS THE
SHORTWAVE OVER NORTHERN KANSAS PUSHES EAST. DID INCLUDE SPRINKLES
IN THE FORECAST FOR THE SOUTHWEST COUNTIES WITH THESE SHOWERS BUT
THEY SHOULD END BY NOON.
TODAY...THE SHORTWAVE OVER SOUTHERN COLORADO WILL MOVE INTO EASTERN
COLORADO...BUT THEN GETS CAUGHT IN THE SOUTHWEST FLOW WHICH KEEPS
THE MAJORITY OF THE ENERGY ACROSS KANSAS. COULD SEE FURTHER
DEVELOPMENT OF HIGH BASED SHOWERS AND ISOLATED THUNDERSTORMS
ASSOCIATED WITH THIS ENERGY...BUT EXPECT IT TO STAY ACROSS THE FAR
WESTERN PARTS OF THE FORECAST AREA. WITH A GOOD AMOUNT OF MOISTURE
IN THE MID AND HIGH LEVELS ASSOCIATED WITH THE UPPER LOW WILL
CONTINUE TO SEE PARTLY TO MOSTLY CLOUDY SKIES ACROSS THE SOUTHWEST
HALF OF NEBRASKA TODAY. THIS WILL BE THE TREND FOR THE NEXT
SEVERAL DAYS AS WELL...WHILE THE UPPER LOW STAYS OFF TO THE WEST
OF THE FORECAST AREA. TEMPERATURES ALOFT WARM SLIGHTLY FROM
YESTERDAY SO EXPECT HIGHS A FEW DEGREES WARMER TODAY DESPITE THE
CLOUD COVER. THE WARMEST READINGS SHOULD BE OVER NORTH CENTRAL
NEBRASKA WHERE SUNSHINE SHOULD BE PLENTIFUL.
FOR WEDNESDAY...THE MAIN UPPER LOW PROGRESSES EAST INTO COLORADO.
AS SAID ABOVE...MOISTURE WILL CONTINUE TO BE PULLED INTO THE
REGION AHEAD OF THE SYSTEM...BUT MAINLY IN THE MID LEVELS /ABOVE
700MB/. MEANWHILE...DRY HIGH PRESSURE WILL REMAIN IN PLACE OVER
THE UPPER MISSISSIPPI RIVER VALLEY REGION. EASTERLY FLOW WILL
CONTINUE TO PULL DRY AIR INTO NEBRASKA IN THE LOWER LEVELS TO KEEP
THE AIR VERY DRY IN THE BOUNDARY LAYER. ALTHOUGH...SHOWERS MAY
DEVELOP ON WEDNESDAY AS INCREASED LIFT ASSOCIATED WITH THE UPPER
LEVEL LOW MOVES INTO WESTERN NEBRASKA...THE VERY DRY AIR IN THE
BOUNDARY LAYER WILL PROHIBIT THE AREA FROM SEEING A GOOD CHANCE
FOR MEASURABLE RAINFALL. WILL NOT CHANGE MUCH FROM PREVIOUS
FORECAST...KEEPING ONLY A SLIGHT CHANCE FOR MEASURABLE RAIN
WEDNESDAY.
THE CLOSED LOW WILL MIGRATE EAST AND BECOME AN OPEN WAVE THURSDAY
AND THURSDAY NIGHT. THE MAIN CIRCULATION LOOKS TO TRACK ALONG THE
NEBRASKA KANSAS BORDER...WHICH WILL BRING THE HIGHEST CHANCE FOR
RAIN THROUGH THESE PERIODS. IN ADDITION...THE SHORTWAVE TROUGH
CURRENTLY OVER THE PACIFIC NORTHWEST WILL TRACK INTO THE NORTHERN
PLAINS WHICH WILL DRIVE A PACIFIC COLD FRONT TOWARDS THE AREA. IN
ADDITION TO THE RAIN CHANCES WITH THE UPPER LOW...THERE COULD BE
SOME DEVELOPMENT OF THUNDERSTORMS AHEAD OF THIS COLD FRONT WHICH
WOULD MAINLY IMPACT PARTS OF THE PANHANDLE AND WESTERN SANDHILLS.
AGAIN...DRY AIR WILL BE IN PLACE IN THE LOWER LEVELS SO DON/T HAVE
A LOT OF CONFIDENCE ON THE COVERAGE OF ANY RAIN. SO HAVE CONTINUED
THE LOWER CHANCES THROUGH THIS TIME PERIOD.
LONG TERM...FRIDAY THROUGH MONDAY
MODEL SOLUTIONS DIVERGE FURTHER WITH TIME GOING INTO THE WEEKEND.
THE UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS MENTIONED ABOVE
WILL CONTINUE TO HAVE SOME IMPACT ON THE FORECAST AREA THROUGH THE
FIRST PART OF THE WEEKEND. THE MAIN ISSUES WITH HOW THIS
PROGRESSES IS FROM HOW THE UPPER LOW OVER THE GREAT LAKES BEHAVES. THERE
ARE INDICATIONS THAT IT WILL NOT SEE MUCH MOVEMENT /IF THE ECMWF
VERIFIES KEEPING THE UPPER LOW OVER THE GREAT LAKES/FROM THURSDAY
NIGHT THROUGH SATURDAY...KEEPING THE COLD FRONT ACROSS THE HIGH
PLAINS. THIS WOULD LEAD TO POTENTIAL FOR STORMS AND SHOWERS BOTH
FRIDAY AND SATURDAY. ON THE OTHER HAND...IF THE NORTHEAST SYSTEM
IS MORE PROGRESSIVE WHICH WOULD MEAN A DRY FORECAST. WITH LOW
CONFIDENCE...KEPT THE FORECAST DRY THIS CYCLE.
FIRE WEATHER...
SEVERAL DAYS WILL SEE LOW RELATIVE HUMIDITY IN THE
AFTERNOON...HOWEVER WINDS THESE DAYS ARE NOT FORECAST TO BE
PARTICULARLY STRONG. CURRENTLY WEDNESDAY AND THURSDAY LOOK TO SEE
THE STRONGEST WINDS /WITH GUSTS TO 20 MPH/...HOWEVER RELATIVE
HUMIDITY BOTH DAYS SHOULD BOTTOM OUT AROUND 25 PERCENT. AT THIS
POINT DO NOT EXPECT THE NEED FOR ANY FIRE WEATHER HEADLINES IN THE
NEXT WEEK.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...POWER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EDT TUE SEP 25 2012
.SYNOPSIS...
AN AREA OF HIGH PRESSURE OFF THE VIRGINIA COAST WILL CONTINUE TO
EXTEND ACROSS THE CAROLINAS TONIGHT AND WEDNESDAY....THEN WEAKEN AND
DRIFT EAST BY THURSDAY. THIS WILL INITIATE A WARMING TREND RESULTING
IN ABOVE NORMAL AFTERNOON TEMPERATURES THROUGH THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM TUESDAY...
1026MB SURFACE HIGH PRESSURE CENTERED JUST EAST OF NORFOLK THIS
EXTENDS SOUTH ALONG THE NC/SC COASTAL PLAIN THIS AFTERNOON.
SOUTHERLY RETURN FLOW AROUND THE HIGH HAS DEVELOPED ACROSS MOST OF
THE CWA...ALLOWING DEWPOINTS TO SLOWLY CREEP BACK INTO THE LOWER
50S. UPSTREAM CONVECTION OVER EASTERN KY IS MOSTLY ELEVATED...BUT
IS A LITTLE MORE IMPRESSIVE THAN HI-RES GUIDANCE SUGGESTED EARLIER
THIS MORNING. RAP FORECAST SOUNDINGS SUGGEST THE STRONG CAPPING
INVERSION ON THE 12Z KGSO RAOB HAS ERODED A BIT TODAY VIA WEAK
COOLING AROUND 700MB...WITH MODEST MID LEVEL LAPSE RATES ABOVE.
HOWEVER... PW EAST OF THE MOUNTAINS IS STILL AROUND 0.5" AND MUCAPE
IS VERY WEAK. ONLY THE MOST RECENT HRRR RUNS SHOW ANY SIMULATED
ECHOS EAST OF THE MOUNTAINS...AND EVEN THEN ARE ONLY A COUPLE
ISOLATED SHOWERS NEAR FORSYTH AND PERSON COUNTIES. WHILE THE RADAR
AND MODEL TRENDS ARE NOT DISCOUNTED...EXPECT THE ONLY IMPACT TO BE
FROM MID AND HIGH CLOUDS OVER THE NORTHWEST PIEDMONT THIS EVENING.
TONIGHT...
LOWS TONIGHT SHOULD NOT BE NEARLY AS COOL DUE TO THE DEWPOINT
RECOVERY TODAY...HELD HIGHER BY MORE CLOUD COVER OVER THE WESTERN
PIEDMONT...WITH MID 50S WEST TO SOME LOWER 50S EAST. PATCHY FOG IS
ALSO POSSIBLE TONIGHT AND SEEMS MOST LIKELY OVER THE SANDHILLS AND
COASTAL PLAIN.
WEDNESDAY AND WEDNESDAY NIGHT...
A STRENGTHENING FRONTAL ZONE STRETCHING FROM THE MID MS RIVER VALLEY
TO THE OHIO VALLEY REGION WILL SINK SLOWLY SOUTHEASTWARD WEDNESDAY
AND BE ORIENTED WEST TO EAST FROM MO TO NORTHERN VA BY WEDNESDAY
NIGHT. THE SURFACE HIGH...WHILE WEAKENING AND SHIFTING FURTHER
OFFSHORE...WILL STILL EXTEND ACROSS NC FOR MOST OF THE DAY. PW WILL
CONTINUE TO CREEP UP TOWARD ON INCH...BUT DESPITE FORECAST SOUNDINGS
SHOWING THE STEEPER MID LEVEL LAPSE RATES LINGERING...MODELS SHOW
ALL CONVECTION WELL NORTH OF THE NC/VA BORDER WHERE A BETTER
PREFRONTAL INSTABILITY AXIS WILL LIE. 850MB TEMPS ARE FORECAST TO
RISE TO AROUND 18C WEDNESDAY AFTERNOON...THOUGH MIXING MAY NOT REACH
QUITE TO 850MB. MIXING TO 925MB INSTEAD YIELDS MOSTLY MID 80S AREA
WIDE. LOWS WEDNESDAY NIGHT AGAIN IN THE LOW TO MID 50S.
&&
.SHORT TERM /THURSDAY AND FRIDAY NIGHT/...
AS OF 240 PM TUESDAY...
MODELS IN ROUGH AGREEMENT IN DEPICTING A WEAK SHORT WAVE MOVING
THROUGH VIRGINIA AND THE CAROLINAS LATE THURSDAY INTO FRIDAY
MORNING. A WEAK FRONT ALONG THE OHIO VALLEY BECOME MORE EAST WEST
ORIENTED AND SLIPS SOUTHWARD IN RESPONSE TO THIS WAVE. WINDS AND
DYNAMICS WITH THIS FRONT CONTINUE QUITE WEAK AND THIS PERIOD MAY
TURN OUT DRY. CURRENTLY BELIEVE THE FRONT WILL REMAIN NORTH IN
VIRGINIA DURING THIS PERIOD. THE BEST RAIN CHANCE IN CENTRAL NORTH
CAROLINA WILL BE LIMITED TO SLIGHT IN THE EXTREME NORTH AND
NORTHWEST... FRIDAY AFTERNOON INTO FRIDAY NIGHT.
THURSDAY STILL LOOKS LIKE THE WARMEST DAY OF THE WORK WEEK WITH LOW
LEVEL THICKNESSES FALLING SLIGHTLY FRIDAY IN RESPONSE TO THE SHORT
WAVE. AFTERNOON HIGH TEMPERATURES 83 TO 88 THURSDAY...82 TO 85
FRIDAY. LOW TEMPERATURES 59 TO 64.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 240 PM TUESDAY...
MODELS CONTINUE TO BE DIVERGENT IN THEIR SOLUTIONS WITH THE LOW
PRESSURE SYSTEM FORECAST TO BE IN SOUTHEAST CANADA SATURDAY MORNING.
THE CANADIAN DEVELOPS A COLD AIR DAMMING (CAD) EVENT DURING THE DAY
SATURDAY... PERSISTING THE CAD TO THE END OF ITS MODEL RUN SUNDAY
EVENING. THE CANADIAN SEEMS TO BE AN OUTLIER IN DEVELOPING A
SIGNIFICANT TROUGH AND CUTTING OFF AN UPPER LOW OVER KENTUCKY
SUNDAY. REJECTING THE CANADIAN MODEL AT THIS TIME. IT DOES APPEAR
THE UPPER SYSTEM WILL RETROGRADE SOUTHWEST TOWARD MICHIGAN DURING
THE WEEKEND. THE GFS AND UKMET HAVE TIMING DIFFERENCES BUT ARE
SIMILAR IN DEPICTING A TROUGH OR CUT OFF LOW EXTENDING TOWARD
MISSISSIPPI OR GEORGIA SATURDAY NIGHT INTO SUNDAY.
SHOULD THE APPROACHING UPPER TROUGH OF THE GFS MODEL COME CLOSE TO
VERIFYING... IT WOULD BE REASONABLE TO HAVE AN INCREASED RAIN CHANCE
SUNDAY AFTERNOON... AND HAVE NUDGED POPS TO ONE IN FOUR. CONTINUING
SLIGHT RAIN CHANCES MOST EVERYWHERE OTHERWISE. CONFIDENCE IN THIS
SCENARIO IS QUITE LOW... AND AWAIT FUTURE MODEL RUNS.
TEMPERATURES WILL CONTINUE TO BE FORECAST WITH AN IDEA TOWARD SOUTH
FLOW AND ENOUGH SUNSHINE DURING THE DAY TO KEEP TEMPERATURES NEAR TO
ABOVE NORMAL IN GENERAL. HIGH TEMPERATURES IN THE LOWER 80S
SATURDAY... OTHERWISE 75 TO NEAR 80. LOW TEMPERATURES 59 TO 65.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 135 PM TUESDAY...
PREDOMINATELY VFR CONDITIONS WILL CONTINUE THROUGH THE TAF
PERIOD...AS HIGH PRESSURE JUST OFF THE VA COAST CONTINUES TO EXTEND
SOUTHWEST ACROSS EASTERN NC. A CLUSTER OF STORMS OVER KY IS
APPROACHING THE VA/NC MOUNTAINS...BUT SHOULD WEAKEN AS IT ENCOUNTERS
THE MOUNTAINS AND A MORE STABLE ENVIRONMENT EAST OF THE
MOUNTAINS..AND ONLY HIGH CLOUDS ARE EXPECTED TO OVERSPREAD KINT/KGSO
THIS EVENING. MEANWHILE...A LIGHT SOUTHERLY TO SOUTHWESTERLY
RETURN FLOW HAS DEVELOPED OVER WESTERN NC...ALLOWING LOW LEVEL
MOISTURE TO SLOWLY RETURN ACROSS THE AREA. A LIGHT WIND OVERNIGHT
SHOULD FEND OFF ANY MORE THAN ISOLATED MVFR VSBYS OVER THE WESTERN
PIEDMONT. FURTHER EAST HOWEVER...KFAY AND KRWI COULD SEE MVFR VSBYS
DEVELOP LATE TONIGHT...MAINLY AFTER 09Z.
AVIATION CONDITIONS ARE EXPECTED TO BE VFR AGAIN ON WEDNESDAY...WITH
A LIGHT SOUTHWESTERLY WIND EXPECTED TO DEVELOP ACROSS ALL OF CENTRAL
NC.
OUTLOOK...
A COLD FRONT IS EXPECTED TO MOVE INTO AND STALL ACROSS MID-ATLANTIC
STATES LATE THIS WEEK. THERE IS SOME UNCERTAINTY AS TO HOW FAR
SOUTH THE FRONT WILL MOVE...WHICH LEADS TO UNCERTAIN IN AVIATION
IMPACTS OVER CENTRAL. AT THIS TIME...MOSTLY VFR CONDITIONS ARE
EXPECTED THROUGH SATURDAY...WITH THE POTENTIAL FOR EARLY MORNING
SUB-VFR CONDITIONS OVER THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...BLS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1037 PM EDT WED SEP 26 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL BOUNDARY WILL GRADUALLY MOVE THROUGH THE
OHIO VALLEY THIS WEEK. SOUTH OF THE FRONT...SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO IMPACT THE REGION. HIGH PRESSURE
WILL BUILD IN ON SATURDAY...BUT AN UPPER LEVEL LOW PRESSURE
CENTER WILL PROVIDE A CHANCE OF SHOWERS ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
TRIED TO REMOVE SHOWERS IN THE I-70 CORRIDOR WEST OF COLUMBUS AND
NOTED THAT PATCHY DENSE FOG IS BEING REPORTED WHERE SKY COVER
ALLOWS RADIATIONAL COOLING TO LOWER TEMPS TO THE ALREADY MOIST
LOWER LAYER OF THE ATMOSPHERE. DO NOT EXPECT THE FOG TO REMAIN FOR
THE ENTIRE OVERNIGHT AS UPSTREAM CLOUD COVER WILL HAMPER THE DROP
IN TEMPERATURES AND VSBYS SHOULD WAFFLE FOR A COUPLE OF HOURS
THROUGH DAYBREAK. ANY CHANCES OF SHOWERS NORTH OF THE METRO CINCY
AREA SHOULD NOT SEE A CHANCE OF THUNDER FOR THE REMAINDER OF THE
NIGHT...I DID NOT ADJUST FORECAST BEYOND DAYBREAK BUT EXPECT THAT
THE ELEVATED INSTABILITY WILL BE LIMITED IN THIS AREA TOMORROW AS
WELL. PREVIOUS DISCUSSION BELOW.
SOUTH OF A SLOWLY-MOVING COLD FRONT...THE CWA REMAINS ENTRENCHED
IN AN AREA OF DEEP MOISTURE AND MODERATE WEST-SOUTHWESTERLY FLOW
IN THE LOWER TO MID LEVELS. THE PRIMARY FORECAST FOCUS IS ON
CONVECTIVE CHANCES AND TIMING TONIGHT.
CONVECTION ONGOING ACROSS THE CWA APPEARS TO BE ASSOCIATED WITH A
WEAK VORTICITY CENTER OVER INDIANA...WITH THE NEW DEVELOPMENT
FIRING UP ON A BAND WELL OUT AHEAD OF IT. MEANWHILE...THE WSW-ENE
ORIENTED BAND OF SHOWERS (WITH EMBEDDED THUNDER) THROUGH CENTRAL
OHIO IS JUST AHEAD OF THE BOUNDARY. INSTABILITY HAS BUILT TO ABOUT 1000
J/KG IN NORTHERN KENTUCKY...AND IS GREATER FURTHER TO THE
SOUTHWEST. RUC13 INSTABILITY FORECASTS OF 2000-2500 J/KG ARE MUCH
TOO HIGH...GIVEN THE ERRONEOUS ADVECTION OF DEWPOINTS OVER 70
DEGREES INTO SW OHIO.
POPS ARE CATEGORICAL FOR THE FIRST FEW HOURS OF THE FORECAST...AS
THE CURRENT ACTIVITY WORKS ITS WAY THROUGH THE CWA. AFTER
THAT...MUCH OF THE CWA MAY SEE A BREAK FROM CONVECTIVE
POTENTIAL...IN THE WAKE OF THE AFTERNOON SYSTEM. WHERE INSTABILITY
IS GREATER IN THE SOUTH...ADDITIONAL DEVELOPMENT IS POSSIBLE.
GIVEN THE 40 KNOTS OF 0-3 KM SHEAR (WHICH IS ACTUALLY STRONGER
THAN THE 0-6 KM SHEAR)...SOME STORM ORGANIZATION AND A FEW STRONG
CELLS WILL BE POSSIBLE. WITHOUT A KEY TRIGGER OR MUCH
INSTABILITY...WIDESPREAD SEVERE WEATHER DOES NOT APPEAR POSSIBLE.
POPS WILL BE KEPT IN THE LIKELY CATEGORY FOR THE SOUTHEASTERN TWO
THIRDS OF THE CWA GOING INTO TONIGHT. HOWEVER...GIVEN THE LACK OF
PRECIPITATION BEHIND THE CURRENT INDIANA/OHIO SYSTEM...IT APPEARS
THAT THE ACTIVITY WILL BE SHOWERY AND NOT ALL OF IT WILL BE
CONVECTIVE. DEVELOPING STORMS IN SOUTHERN ILLINOIS MAY BE WHAT
ENDS UP PROVIDING A GREATER CHANCE OF PRECIPITATION LATER ON
TONIGHT.
THE HOLES IN THE CLOUD COVER ALLOWED THE SOUTHERN CWA TO APPROACH
80 DEGREES TODAY. GIVEN THE WARMER STARTING POINT...AND EXPECTED
MOIST AND CLOUDY ATMOSPHERE TONIGHT...MIN TEMPS IN THE SOUTH WERE
BUMPED UP A FEW DEGREES FROM THE PREVIOUS FORECAST. WITH THE FRONT
MOVING INTO THE AREA...AND COLD ADVECTION BEGINNING IN THE
NORTH...THE TEMPERATURE GRADIENT OVERNIGHT WILL BE SOMEWHAT TIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL CONTINUE TO MAKE VERY SLOW PROGRESS TO
THE EAST ON THURSDAY...BUT ENOUGH PROGRESS TO BRING AN END TO ANY
SIGNIFICANT CHANCES OF PRECIPITATION. THE FRONT WILL ORIENT ITSELF
EAST-TO-WEST ACROSS KENTUCKY...AND STALL OUT THROUGH FRIDAY. THIS
MEANS THAT THE MOISTURE AND FORCING ASSOCIATED WITH THE FRONT WILL
BE VERY CLOSE TO THE SOUTHERN EDGE OF THE FORECAST AREA. THIS
WILL REQUIRE A CHANCE OF SHOWERS (WITH A POSSIBILITY OF
THUNDERSTORMS) IN THE SOUTHERN HALF OF THE CWA FOR THURSDAY...AND
THEN JUST THE SOUTHERN THIRD OF THE CWA ON FRIDAY. AS THE VARIOUS
MODELS (AND THEIR VARIOUS RUNS) CONTINUE TO STRUGGLE WITH TIMING
THE EMBEDDED DISTURBANCES IN THE QUICK LOWER-TO-MID-LEVEL
FLOW...IT REMAINS DIFFICULT TO PIN DOWN THE TIME OR PLACEMENT OF
ANY NORTHWARD-IMPINGING CONVECTIVE SYSTEMS THAT MAY IMPACT THE CWA
DURING THIS TIME FRAME.
MAX TEMPERATURES WERE ADJUSTED SLIGHTLY DOWN THROUGH THE END OF
THE WEEK...AS THE COLD ADVECTION BEHIND THE FRONT WILL KEEP TEMPS
FROM REACHING 70. THE TEMPERATURE GRADIENT WILL BE TIGHTER ON
THURSDAY...WITH THE FRONT STILL IN THE AREA. GUIDANCE AND MODEL
NUMBERS EXHIBITED LITTLE SPREAD...INCREASING CONFIDENCE IN THE
FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. SAT AND SUN
FOCUSED ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU.
TIMING OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT
AND ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR
BOTH SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON
TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD.
SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL
DAYTIME HIGHS.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
CONVECTION THAT IS OCCURRING OVER THE OHIO VALLEY IS OCCURRING IN
THE WARM SECTOR AHEAD OF A COLD FRONT THAT WILL DROP SOUTH INTO
KENTUCKY LATER THIS EVENING. SHOWERS WILL BE FOUND IN ANY TAF SITE
FOR THE EARLY PART OF THE NIGHT...WITH SOME THUNDER POSSIBLE
TOWARDS KCVG WHERE THE NOSE OF THE MOST UNSTABLE AIR CLIPS THIS
STATION. BEST INSTABILITY WILL BE FOCUSED OUT OF THE TAF SITES IN
QUESTION...GENERALLY FROM LOUISVILLE SOUTHWESTWARD. MVFR CIGS AND
VSBYS IN SHOWERS WILL OCCASIONALLY BE FOUND BUT MOST STATIONS ARE
REMAINING VFR...EVEN IN THE LIGHTER RAIN THAT MAY HIT THEM.
FRONT WILL DROP SOUTH AND WINDS WILL TURN NORTHEAST BEFORE
MIDNIGHT FOR THE NORTHERN TAF SITES...BY DAYBREAK FOR METRO CINCY.
STILL SOME UNCERTAINTY AS TO WHERE THE BKN-OVC CU DECK WILL FORM
IN THE COLDER POST-FRONTAL AIR...GENERALLY EXPECTED THE SUN TO HIT
THE MOISTENED AIR IN PLACE AND CREATE A BKN DECK 2-3KFT
TOMORROW...WITH DRYING AND MIXING OCCURRING IN THE
AFTERNOON...ESPECIALLY FOR THE NORTH WHERE SKIES MAY ACTUALLY GO
CLEAR BEFORE 0Z.
.OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...FRANKS/HATZOS
SHORT TERM...HATZOS
LONG TERM...PADGETT
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
737 PM EDT WED SEP 26 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL BOUNDARY WILL GRADUALLY MOVE THROUGH THE
OHIO VALLEY THIS WEEK. SOUTH OF THE FRONT...SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO IMPACT THE REGION. HIGH PRESSURE
WILL BUILD IN ON SATURDAY...BUT AN UPPER LEVEL LOW PRESSURE
CENTER WILL PROVIDE A CHANCE OF SHOWERS ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SOUTH OF A SLOWLY-MOVING COLD FRONT...THE CWA REMAINS ENTRENCHED
IN AN AREA OF DEEP MOISTURE AND MODERATE WEST-SOUTHWESTERLY FLOW
IN THE LOWER TO MID LEVELS. THE PRIMARY FORECAST FOCUS IS ON
CONVECTIVE CHANCES AND TIMING TONIGHT.
CONVECTION ONGOING ACROSS THE CWA APPEARS TO BE ASSOCIATED WITH A
WEAK VORTICITY CENTER OVER INDIANA...WITH THE NEW DEVELOPMENT
FIRING UP ON A BAND WELL OUT AHEAD OF IT. MEANWHILE...THE WSW-ENE
ORIENTED BAND OF SHOWERS (WITH EMBEDDED THUNDER) THROUGH CENTRAL
OHIO IS JUST AHEAD OF THE BOUNDARY. INSTABILITY HAS BUILT TO ABOUT 1000
J/KG IN NORTHERN KENTUCKY...AND IS GREATER FURTHER TO THE
SOUTHWEST. RUC13 INSTABILITY FORECASTS OF 2000-2500 J/KG ARE MUCH
TOO HIGH...GIVEN THE ERRONEOUS ADVECTION OF DEWPOINTS OVER 70
DEGREES INTO SW OHIO.
POPS ARE CATEGORICAL FOR THE FIRST FEW HOURS OF THE FORECAST...AS
THE CURRENT ACTIVITY WORKS ITS WAY THROUGH THE CWA. AFTER
THAT...MUCH OF THE CWA MAY SEE A BREAK FROM CONVECTIVE
POTENTIAL...IN THE WAKE OF THE AFTERNOON SYSTEM. WHERE INSTABILITY
IS GREATER IN THE SOUTH...ADDITIONAL DEVELOPMENT IS POSSIBLE.
GIVEN THE 40 KNOTS OF 0-3 KM SHEAR (WHICH IS ACTUALLY STRONGER
THAN THE 0-6 KM SHEAR)...SOME STORM ORGANIZATION AND A FEW STRONG
CELLS WILL BE POSSIBLE. WITHOUT A KEY TRIGGER OR MUCH
INSTABILITY...WIDESPREAD SEVERE WEATHER DOES NOT APPEAR POSSIBLE.
POPS WILL BE KEPT IN THE LIKELY CATEGORY FOR THE SOUTHEASTERN TWO
THIRDS OF THE CWA GOING INTO TONIGHT. HOWEVER...GIVEN THE LACK OF
PRECIPITATION BEHIND THE CURRENT INDIANA/OHIO SYSTEM...IT APPEARS
THAT THE ACTIVITY WILL BE SHOWERY AND NOT ALL OF IT WILL BE
CONVECTIVE. DEVELOPING STORMS IN SOUTHERN ILLINOIS MAY BE WHAT
ENDS UP PROVIDING A GREATER CHANCE OF PRECIPITATION LATER ON
TONIGHT.
THE HOLES IN THE CLOUD COVER ALLOWED THE SOUTHERN CWA TO APPROACH
80 DEGREES TODAY. GIVEN THE WARMER STARTING POINT...AND EXPECTED
MOIST AND CLOUDY ATMOSPHERE TONIGHT...MIN TEMPS IN THE SOUTH WERE
BUMPED UP A FEW DEGREES FROM THE PREVIOUS FORECAST. WITH THE FRONT
MOVING INTO THE AREA...AND COLD ADVECTION BEGINNING IN THE
NORTH...THE TEMPERATURE GRADIENT OVERNIGHT WILL BE SOMEWHAT TIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL CONTINUE TO MAKE VERY SLOW PROGRESS TO
THE EAST ON THURSDAY...BUT ENOUGH PROGRESS TO BRING AN END TO ANY
SIGNIFICANT CHANCES OF PRECIPITATION. THE FRONT WILL ORIENT ITSELF
EAST-TO-WEST ACROSS KENTUCKY...AND STALL OUT THROUGH FRIDAY. THIS
MEANS THAT THE MOISTURE AND FORCING ASSOCIATED WITH THE FRONT WILL
BE VERY CLOSE TO THE SOUTHERN EDGE OF THE FORECAST AREA. THIS
WILL REQUIRE A CHANCE OF SHOWERS (WITH A POSSIBILITY OF
THUNDERSTORMS) IN THE SOUTHERN HALF OF THE CWA FOR THURSDAY...AND
THEN JUST THE SOUTHERN THIRD OF THE CWA ON FRIDAY. AS THE VARIOUS
MODELS (AND THEIR VARIOUS RUNS) CONTINUE TO STRUGGLE WITH TIMING
THE EMBEDDED DISTURBANCES IN THE QUICK LOWER-TO-MID-LEVEL
FLOW...IT REMAINS DIFFICULT TO PIN DOWN THE TIME OR PLACEMENT OF
ANY NORTHWARD-IMPINGING CONVECTIVE SYSTEMS THAT MAY IMPACT THE CWA
DURING THIS TIME FRAME.
MAX TEMPERATURES WERE ADJUSTED SLIGHTLY DOWN THROUGH THE END OF
THE WEEK...AS THE COLD ADVECTION BEHIND THE FRONT WILL KEEP TEMPS
FROM REACHING 70. THE TEMPERATURE GRADIENT WILL BE TIGHTER ON
THURSDAY...WITH THE FRONT STILL IN THE AREA. GUIDANCE AND MODEL
NUMBERS EXHIBITED LITTLE SPREAD...INCREASING CONFIDENCE IN THE
FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. SAT AND SUN
FOCUSED ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU.
TIMING OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT
AND ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR
BOTH SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON
TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD.
SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL
DAYTIME HIGHS.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
CONVECTION THAT IS OCCURRING OVER THE OHIO VALLEY IS OCCURRING IN
THE WARM SECTOR AHEAD OF A COLD FRONT THAT WILL DROP SOUTH INTO
KENTUCKY LATER THIS EVENING. SHOWERS WILL BE FOUND IN ANY TAF SITE
FOR THE EARLY PART OF THE NIGHT...WITH SOME THUNDER POSSIBLE
TOWARDS KCVG WHERE THE NOSE OF THE MOST UNSTABLE AIR CLIPS THIS
STATION. BEST INSTABILITY WILL BE FOCUSED OUT OF THE TAF SITES IN
QUESTION...GENERALLY FROM LOUISVILLE SOUTHWESTWARD. MVFR CIGS AND
VSBYS IN SHOWERS WILL OCCASIONALLY BE FOUND BUT MOST STATIONS ARE
REMAINING VFR...EVEN IN THE LIGHTER RAIN THAT MAY HIT THEM.
FRONT WILL DROP SOUTH AND WINDS WILL TURN NORTHEAST BEFORE
MIDNIGHT FOR THE NORTHERN TAF SITES...BY DAYBREAK FOR METRO CINCY.
STILL SOME UNCERTAINTY AS TO WHERE THE BKN-OVC CU DECK WILL FORM
IN THE COLDER POST-FRONTAL AIR...GENERALLY EXPECTED THE SUN TO HIT
THE MOISTENED AIR IN PLACE AND CREATE A BKN DECK 2-3KFT
TOMORROW...WITH DRYING AND MIXING OCCURRING IN THE
AFTERNOON...ESPECIALLY FOR THE NORTH WHERE SKIES MAY ACTUALLY GO
CLEAR BEFORE 0Z.
.OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...PADGETT
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
223 PM EDT TUE SEP 25 2012
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TODAY...BECOMING
STATIONARY THROUGH WEDNESDAY. THIS FRONT WILL BE OVERTAKEN BY A
COLD FRONT DROPPING SOUTH FROM THE GREAT LAKES LATE WEDNESDAY AND
THURSDAY. UNSETTLED WEATHER WILL RESULT UNTIL DRIER AIR WORKS IN
FROM THE NORTH LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA OF CONVECTION CONTINUES TO WORK E ACROSS THE REGION. IT IS HOLDING
TOGETHER BETTER ACROSS THE KY COUNTIES. THE LATEST HRRR
RUN...WHICH INITIALIZED PRETTY WELL...TAKES THE SRN PORTION OF THE
SYSTEM THRU THE FA. THE NRN HALF APPEARS TO BE WEAKENING AS IT
COMES IN. THE MATCHES WHAT THE HRRR IS FORECASTING.
LATER THIS AFTN...A WRM FNT LIFTING OUT OF MO...WILL COMBINE WITH
A CDFNT DROPPING SOUTHEAST TO CREATE AN AREA OF LIFT ACROSS THE
MIAMI VALLEY. AS THE LIFT DEVELOPS...CONVECTION WILL DEVELOP MAINLY
ALONG AND NORTH OF I-70.
KEPT HIGHS IN THE UPPER 60S ACROSS THE N...WARMING TO THE MID 70S
ACROSS NRN KY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
LOW LEVEL JET WILL INCREASE IN INTENSITY TONIGHT ALONG THE SLOW
MOVING FRONT WHICH WILL ENHANCE THUNDERSTORM DEVELOPMENT AND
STRENGTH. KEPT POPS AS HIGH AS CATEGORICAL. THERE WILL BE A LOW
CHANCE FOR SEVERE THUNDERSTORMS WITH MARGINAL INSTABILITY THE
LIMITING FACTOR IN A REGIME OF VIGOROUS WIND FIELDS.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE LIKELY ON WEDNESDAY
AS THE FRONT MAKES ITS WAY ACROSS THE AREA. THERE MAY BE A BETTER
CHANCE FOR SEVERE THUNDERSTORMS SINCE INSTABILITY WILL BE
INCREASING IN THE PRESENCE OF PERSISTENTLY STRONG WIND FLOW.
RAINFALL TOTALS FOR THIS EVENT WILL PROBABLY EXCEED AN INCH IN
SOME LOCATIONS.
THE FRONT IS EXPECTED TO BE SITUATED NEAR THE OHIO RIVER WEDNESDAY
NIGHT AND THURSDAY. THIS SCENARIO WILL KEEP A GOOD CHANCE FOR
SHOWERS AND THUNDERSTORMS OVER SOUTHERN COUNTIES DURING THAT
TIME FRAME.
HIGH TEMPERATURES WILL BE NEAR NORMAL...MAINLY IN THE 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THERE IS UNCERTAINTY WHERE A NEARLY STATIONARY FRONT WILL SET UP.
BUT AT THIS POINT IT APPEARS THAT IT WILL BE CLOSE ENOUGH TO THE
SOUTHERN ZONES TO KEEP A CHANCE OF SHOWERS AND POSSIBLY SOME THUNDER
INTO FRIDAY. EXPECT THE BOUNDARY TO FINALLY GET PUSHED FURTHER
SOUTH AS HIGH PRESSURE BUILDS IN ON THE BACK SIDE OF A DEVELOPING
UPPER LOW. THIS SHOULD SPREAD DRIER AIR ACROSS THE REGION FOR THE
WEEKEND INTO MONDAY. TEMPERATURES WILL BE NEAR NORMAL THROUGH THE
PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
MORNING CONVECTION SLID MAINLY S OF THE TAFS...AS THE NORTHERN
PART OF THE SYSTEM FELL APART. BEHIND THE CONVECTION IFR/MVFR CIGS
HAVE WORKED INTO THE TAFS.
THE CIGS ACROSS INDIANA HAVE GRADUALLY RISING AND THE VFR
CONDITIONS SHOULD WORK EWD INTO THE TAFS BY 00Z.
FOCUS NOW SHIFTS TO ANOTHER H5 S/W THAT IS MOVG E THROUGH THE
CONFLUENT FLOW OVER THE OHIO RIVER VALLEY. LOW LEVEL FORCING
INCREASES AFT 21Z OUT AHEAD OF A DIGGING CDFNT. MODELS DEVELOP A
LARGE AREA OF CONVECTION ALONG THE I-70 CORRIDOR. THERE IS SOME
TIMING DIFFERENCES WITH THE ONSET...BUT MOST SUGGEST DEVELOPMENT
AROUND 00Z IN THE W. WENT WITH A PREVAILING MVFR VSBY IN SHRA.
THERE IS INSTABILITY TO WORK WITH...BUT ONLY PUT TS IN A VC GROUP
AT THIS TIME.
AS THE NIGHT PROGRESSES THE FRONT SETTLES TO THE S PUSHING THE
BETTER CONVECTION TOWARDS THE SRN TAFS. A WAVE ON THE FRONT
PUSHES THROUGH AROUND 12Z...PUSHING THE BETTER CHC OF PCPN EWD.
TAPERED THE SHRA TO VC AFTER 12Z...BUT BROUGHT MVFR CIGS IN BEHIND
THE WAVE.
.OUTLOOK...THUNDERSTORMS AND MVFR CONDITIONS POSSIBLE THROUGH
THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1106 AM EDT TUE SEP 25 2012
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TODAY...BECOMING
STATIONARY THROUGH WEDNESDAY. THIS FRONT WILL BE OVERTAKEN BY A
COLD FRONT DROPPING SOUTH FROM THE GREAT LAKES LATE WEDNESDAY AND
THURSDAY. UNSETTLED WEATHER WILL RESULT UNTIL DRIER AIR WORKS IN
FROM THE NORTH LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA OF CONVECTION CONTINUES TO WORK E ACROSS THE REGION. IT IS HOLDING
TOGETHER BETTER ACROSS THE KY COUNTIES. THE LATEST HRRR
RUN...WHICH INITIALIZED PRETTY WELL...TAKES THE SRN PORTION OF THE
SYSTEM THRU THE FA. THE NRN HALF APPEARS TO BE WEAKENING AS IT
COMES IN. THE MATCHES WHAT THE HRRR IS FORECASTING.
LATER THIS AFTN...A WRM FNT LIFTING OUT OF MO...WILL COMBINE WITH
A CDFNT DROPPING SOUTHEAST TO CREATE AN AREA OF LIFT ACROSS THE
MIAMI VALLEY. AS THE LIFT DEVELOPS...CONVECTION WILL DEVELOP MAINLY
ALONG AND NORTH OF I-70.
KEPT HIGHS IN THE UPPER 60S ACROSS THE N...WARMING TO THE MID 70S
ACROSS NRN KY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
LOW LEVEL JET WILL INCREASE IN INTENSITY TONIGHT ALONG THE SLOW
MOVING FRONT WHICH WILL ENHANCE THUNDERSTORM DEVELOPMENT AND
STRENGTH. KEPT POPS AS HIGH AS CATEGORICAL. THERE WILL BE A LOW
CHANCE FOR SEVERE THUNDERSTORMS WITH MARGINAL INSTABILITY THE
LIMITING FACTOR IN A REGIME OF VIGOROUS WIND FIELDS.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE LIKELY ON WEDNESDAY
AS THE FRONT MAKES ITS WAY ACROSS THE AREA. THERE MAY BE A BETTER
CHANCE FOR SEVERE THUNDERSTORMS SINCE INSTABILITY WILL BE
INCREASING IN THE PRESENCE OF PERSISTENTLY STRONG WIND FLOW.
RAINFALL TOTALS FOR THIS EVENT WILL PROBABLY EXCEED AN INCH IN
SOME LOCATIONS.
THE FRONT IS EXPECTED TO BE SITUATED NEAR THE OHIO RIVER WEDNESDAY
NIGHT AND THURSDAY. THIS SCENARIO WILL KEEP A GOOD CHANCE FOR
SHOWERS AND THUNDERSTORMS OVER SOUTHERN COUNTIES DURING THAT
TIME FRAME.
HIGH TEMPERATURES WILL BE NEAR NORMAL...MAINLY IN THE 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THERE IS UNCERTAINTY WHERE A NEARLY STATIONARY FRONT WILL SET UP.
BUT AT THIS POINT IT APPEARS THAT IT WILL BE CLOSE ENOUGH TO THE
SOUTHERN ZONES TO KEEP A CHANCE OF SHOWERS AND POSSIBLY SOME THUNDER
INTO FRIDAY. EXPECT THE BOUNDARY TO FINALLY GET PUSHED FURTHER
SOUTH AS HIGH PRESSURE BUILDS IN ON THE BACK SIDE OF A DEVELOPING
UPPER LOW. THIS SHOULD SPREAD DRIER AIR ACROSS THE REGION FOR THE
WEEKEND INTO MONDAY. TEMPERATURES WILL BE NEAR NORMAL THROUGH THE
PERIOD.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
WESTERLY FLOW ALOFT WITH A MID LEVEL SHORT WAVE TRACKING FROM THE
MID MISSISSIPPI VALLEY EARLY THIS MORNING ACROSS ILN/S FA DURING
THE DAY. AHEAD OF THIS FEATURE MID AND HIGH LEVEL CLOUDS HAVE
INCREASED OVERNIGHT. DUE TO ISENTROPIC LIFT AND ELEVATED INSTBY
ISOLD SHOWERS/THUNDERSTORMS HAVE DEVELOPED ACRS THE NRN MIAMI VLY.
THIS ACTIVITY SHUD WEAKENING BUT CUD PROVIDE A SHOWER TO CENTRAL
OHIO TAF SITES EARLY. BETTER FORCING MOVES IN DURG THE DAY WITH
MARGINAL INSTBY DEVELOPING. SCATTERED SHOWERS AND A FEW
THUNDERSTORMS WILL BECOME MORE WIDESPREAD THROUGH THE LATE
AFTERNOON AND ESPECIALLY INTO TONIGHT. THERE CONTINUES TO BE SOME
MODEL SOLN DIFFERENCES AS TO EXACTLY WHERE THE BEST CHANCE FOR
PCPN WILL LINE UP. IT APPEARS THAT NORTHERN PORTIONS OF OUR FA MAY
HAVE THE BETTER CHANCE DURG THE AFTN AND THEN CHANCES IMPROVE ACRS
ALL TAF SITES THRU THE EVENING. HAVE CONTINUED VFR CIGS WITH
PREVAILING SHOWERS DEVELOPING AND VCTS FOR THUNDER INTO THE
EVENING WITH CIGS AND VSBYS LOWERING INTO MVFR CATEGORY LATE IN
THE TAF PERIOD.
.OUTLOOK...THUNDERSTORMS AND MVFR CONDITIONS POSSIBLE THROUGH
WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...SITES
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
151 AM EDT TUE SEP 25 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL BEGIN TO APPROACH THE AREA TONIGHT.
A FRONTAL BOUNDARY WILL SETTLE INTO THE AREA KEEPING PRECIPITATION
CHANCES IN THE FORECAST FOR MUCH OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SKIES ARE CLEAR ACROSS THE AREA THIS EVENING...BUT EXPECT TO SEE
AN INCREASE IN CLOUDS LATER TONIGHT AS A MID LEVEL SHORT WAVE
APPROACHES FROM THE WEST. AHEAD OF THIS...THE LOW LEVEL FLOW WILL
BACK SLIGHTLY AND WE WILL SEE SOME DEVELOPING ISENTROPIC LIFT
TOWARD DAYBREAK. THIS COULD LEAD TO A FEW SHOWERS LATE. THE 18Z NAM
AND LATEST RAP ARE BOTH SHOWING SOME WEAK ELEVATED INSTABILITIES
WORKING IN LATE TONIGHT TOO SO WILL HANG ON TO THUNDER WORDING
ALTHOUGH THINK THE CHANCE WILL BE PRETTY LOW.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
A FRONTAL BOUNDARY WILL APPROACH AND THEN MEANDER AROUND THE FA
THROUGH THE SHORT TERM TIME FRAME. THIS WILL ALLOW FOR OFF AND ON
PRECIPITATION THROUGH THIS TIME. THERE IS STILL SOME UNCERTAINTY
IN WHERE THE EXACT LOCATION OF THE BOUNDARY WILL BE HOWEVER CURRENT
INDICATIONS ARE THAT SOME LOCATIONS ACROSS CENTRAL PORTIONS OF THE
FA WILL HAVE THE POTENTIAL FOR AN INCH OR TWO OF RAIN THROUGH THE
SHORT TERM TIME FRAME. THE FRONTAL BOUNDARY WILL BEGIN TO MOVE
SOUTH BY THE END OF THE SHORT TERM ENDING PRECIPITATION CHANCES
ACROSS NORTHERN PORTIONS OF THE FA. WITH DECENT INSTABILITY ACROSS
THE AREA ON WEDNESDAY A FEW OF THE STORMS MAY BE STRONG TO SEVERE
WITH DAMAGING WINDS AND HAIL THE PRIMARY THREATS. HIGH TEMPERATURES
WILL GENERALLY BE IN THE 70S WITH LOWS IN THE 50S AND 60S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THERE IS UNCERTAINTY WHERE A NEARLY STATIONARY FRONT WILL SET UP.
BUT AT THIS POINT IT APPEARS THAT IT WILL BE CLOSE ENOUGH TO THE
SOUTHERN ZONES TO KEEP A CHANCE OF SHOWERS AND POSSIBLY SOME THUNDER
THURSDAY INTO FRIDAY. EXPECT THE BOUNDARY TO FINALLY GET PUSHED
FURTHER SOUTH AS HIGH PRESSURE BUILDS IN ON THE BACK SIDE OF A
DEVELOPING UPPER LOW. THIS SHOULD SPREAD DRIER AIR ACROSS THE REGION
FOR THE WEEKEND INTO MONDAY. TEMPERATURES WILL BE NEAR NORMAL
THROUGH THE PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
WESTERLY FLOW ALOFT WITH A MID LEVEL SHORT WAVE TRACKING FROM THE
MID MISSISSIPPI VALLEY EARLY THIS MORNING ACROSS ILN/S FA DURING
THE DAY. AHEAD OF THIS FEATURE EXPECT TO SEE AN INCREASE IN HIGH
AND THEN MID LEVEL CLOUDS TOWARD SUNRISE. WITH ISENTROPIC LIFT
DEVELOPING A FEW SPRINKLES OR LIGHT RAIN SHOWERS WILL BE POSSIBLE
TOWARD SUNRISE...BUT THESE SHUD BE OPERATIONALLY INSIGNIFICANT WITH
VFR CONDITIONS CONTINUING. BETTER FORCING MOVES IN DURG THE DAY
WITH MARGINAL INSTBY DEVELOPING. SCATTERED SHOWERS AND A FEW
THUNDERSTORMS WILL BECOME MORE WIDESPREAD THROUGH THE LATE AFTERNOON
AND ESPECIALLY INTO TONIGHT. THERE CONTINUES TO BE SOME MODEL SOLN
DIFFERENCES AS TO EXACTLY WHERE THE BEST CHANCE FOR PCPN WILL
LINE UP. RIGHT NOW...IT APPEARS THAT NORTHERN PORTIONS OF OUR FA
MAY HAVE THE BETTER CHANCE DURG THE AFTN AND THEN CHANCES
IMPROVING ACRS ALL TAF SITES THIS EVENING. HAVE CONTINUED VFR CIGS
WITH PREVAILING SHOWERS DEVELOPING AND VCTS FOR THUNDER LATE IN
THE FCST PERIOD.
.OUTLOOK...THUNDERSTORMS AND MVFR CONDITIONS POSSIBLE THROUGH
WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...JGL
SHORT TERM...NOVAK
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS TULSA OK
1135 PM CDT MON SEP 24 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE VALID
PERIOD AT ALL AREA TAF SITES. WILL ADD PROB30 TSRA FOR
NORTHEAST OKLAHOMA TAF SITES AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 942 PM CDT MON SEP 24 2012/
..UPDATE...
DISCUSSION...
LATEST RUC ANALYSIS SUGGEST THE ELEVATED FRONTAL ZONE WILL REMAIN
WELL TO OUR NORTH AND JUST EAST OF THE FORECAST AREA OVERNIGHT.
THUS WILL REMOVE OVERNIGHT THUNDERSTORM MENTION. WILL ALSO
INCREASE OVERNIGHT CLOUD COVER GIVEN DENSE CIRRUS CANOPY AND MAKE
MINOR ADJUSTMENT TO WIND SPEEDS. THE FIRE WEATHER WATCH WILL
REMAIN IN EFFECT FOR TUESDAY...WITH PORTIONS OF THE WATCH POSSIBLY
UPGRADED TO A RED FLAG WARNING PENDING NEW DATA TRENDS.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FIRE WEATHER WATCH FROM NOON TUESDAY TO 9 PM TUESDAY FOR OKZ049-
OKZ053-OKZ054-OKZ055-OKZ059-OKZ060-OKZ061-OKZ064-OKZ065-
OKZ066-OKZ067-OKZ070-OKZ071-OKZ073-OKZ074-OKZ075-OKZ076.
AR...NONE.
&&
$$
AVIATION...10
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1035 PM EDT WED SEP 26 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONTAL BOUNDARY JUST SOUTHEAST OF THE LAKE ERIE
SHORE WILL DRIFT SOUTH ACROSS THE STATE AND BECOME LOCATED NEAR THE
PENNSYLVANIA...MARYLAND BORDER WHERE IT WILL STALL OUT RIGHT INTO
FRIDAY. THE CLOSE PROXIMITY OF THIS FRONT WILL MAINTAIN THE THREAT
OF OCCASIONAL RAIN OVER THE SOUTHERN THIRD OF THE KEYSTONE STATE FOR
THURSDAY AND FRIDAY. A DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP
SOUTHWARD FROM EASTERN CANADA AND CARVE OUT OVER THE GREAT LAKES
REGION AND NORTHEAST STATES THIS WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THURSDAY MORNING/...
A CHANNEL OF HIGH PWAT AIR /1-1.5 INCHES/ WILL CONTINUE TO STREAM IN
FROM THE OHIO VALLEY...ACROSS THE SOUTHERN TWO THIRDS OF PENN
TONIGHT...AHEAD OF A COLD FRONT THAT WAS CREEPING JUST TO THE SOUTH
OF INTERSTATE 90 ATTM.
ISOLATED TO SCATTERED SHOWERS WILL CONTINUE THROUGH THE OVERNIGHT
HOURS ALONG AND AHEAD OF THIS FRONT. FURTHER SOUTH...THE CURRENT
LACK OF SHOWERS SHOWN ON THE 88D MOSAIC LOOP WILL INCREASE IN
COVERAGE DURING THE PREDAWN HOURS OF THURSDAY AS DEEP LAYER LIFT
DEVELOPS AHEAD OF A SHORTWAVE CURRENTLY CROSSING THE MID MISS RIVER
VALLEY...AND A FAIRLY WELL DEFINED COUPLED JET CIRCULATION DEVELOPS
FURTHER EAST AND UP ALONG THE OHIO RIVER VALLEY.
21Z SREF SHOWS THE BETTER FORCING FOR A FEW MORE AREAS OF LIGHT RAIN
LATE TONIGHT...SETTING UP RIGHT ACROSS THE CENTRAL THIRD OF THE
STATE...WHILE THE 18Z AND 00Z NAM...AND 01Z RUC SHOWS THE NEXT BATCH
OF RAIN TARGETING/BLOSSOMING ACROSS THE SWRN AND SCENT COUNTIES OF
THE CWA AFTER 06Z.
THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF
INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST
SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING
STATIONARY THERE THROUGH THURSDAY NIGHT.
THE MAIN FCST PROBLEM FOR THE NEAR TERM CONTINUES TO BE THE
DISTRIBUTION AND TIMING OF POPS AND AMOUNT OF /GENERALLY LIGHT/
RAINFALL IN MOST PLACES. 12Z EC AND GEFS APPEAR TO BE A BLEND OF THE
3 AFOREMENTIONED MODELS FOR THE 06Z-12Z THUR TIMEFRAME.
A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3 TENTHS
ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS OF THE
STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS POSSIBLY
SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS THE NRN
MTNS.
SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE
OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER
50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS
GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT.
&&
.SHORT TERM /8 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL
PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH.
THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE
MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR
MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND
IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER
LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S.
MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF
THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW
DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED
STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A
STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND
CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY
AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE
REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS
RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA.
THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE
THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT
FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE
UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT
LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO
MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST
COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS
LOW.
CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS
FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE
OHIO VALLEY AND INTO PA.
WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES
WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW
DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO
AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL MOVE SLOWLY SOUTH ACROSS THE CWA OVERNIGHT
WITH WEAK MID-LEVEL WAVES CONTINUING TO MOVE W-E OVERHEAD. THIS
WILL KEEP MENTION OF RAIN FOR MOST TAF SITES OVERNIGHT...WITH BEST
LIKELIHOOD IN KJST-KAOO. CIGS ACROSS THE HIGHER TERRAIN ALREADY
MVFR...AND THESE WILL LOWER TO IFR MAINLY AFTER 06Z AS STRATOCU
DECK THICKENS AND SPREADS INTO CENTRAL MTNS AND LOWER SUSQ /LATE/.
KBFD WILL SEE IFR CONDITIONS AROUND FROPA...THEN GRADUAL
IMPROVEMENT AS 12Z APPROACHES AS DRIER AIR BEGINS TO SLIP IN FROM
THE NW.
THE FRONTAL BOUNDARY WILL MOST LIKELY STALL OUT NEAR THE PA/MD
BORDER ON THU. SO THE THREAT OF SHOWERS WILL CONTINUE OVER THE
SOUTHERN THIRD. CIGS WILL BEGIN AT IFR/MVFR BUT GRADUALLY RETURN
TO VFR BY MID/LATE MORNING...WITH INTERMITTENT REDUCTIONS IN
SHOWERS ACROSS THE SOUTH.
OUTLOOK...
FRI-SUN...VFR TO MVFR WITH SCT SHOWERS - MAINLY S AND E.
MON...SHOWERS POSS NW...VFR ELSEWHERE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1231 PM CDT TUE SEP 25 2012
.UPDATE...FOR AVIATION.
&&
.AVIATION...
A FRONT WILL REMAIN STALLED TO OUR NORTH THROUGH THE TAF PD.
ACTIVE SOUTHERN JET WILL TRANSPORT MOISTURE IN THE FORM OF
MID/HIGH LEVEL CLOUDINESS ACROSS THE TAF AREAS. VFR CONDITIONS ARE
EXPECTED WITH SOMETIMES GUSTY SSW WINDS.
13
&&
.PREV DISCUSSION... /ISSUED 1200 PM CDT TUE SEP 25 2012/
DISCUSSION...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO LOWER HIGH TEMPS BY
A COUPLE OF DEGREES ACROSS LOCATIONS W OF THE PLATEAU FOR THIS AFTERNOON
AND TO ADDRESS MOCLDY SKY CONDTIONS ACROSS MOST LOCATIONS FOR THIS
AFTERNOON TOO.
PREV DISCUSSION.../ISSUED 1026 AM CDT TUE SEP 25 2012/
UPDATE...
WITH MOST CONVECTIVE ACTIVITY MOVING W TO OUR N ACROSS CNTRL AND NOW
INTO ERN KY...AND PER REGIONAL SATELLITE...RADAR MOSAICS...AND SFC OBS...
BELIEVE THAT WITH QUASI ZONAL FLOW PATTERN ALOFT...THE MID STATE SHOULD
GENERALLY ONLY EXPERIENCE AN INCREASING CLOUDINESS TREND THRU THE REMAINDER
OF THE MORNING HRS W THRU THE EARLY AFTERNOON HRS E...WITH CLRING POSSIBLE
ACROSS THE ENTIRE MID STATE BY THE LATE AFTERNOON HRS. BEST INSTABILITY
SHOULD REMAIN TO OUR N...AND BELIEVE IF ANY RAINFALL DOES OCCUR...AS 12Z
KOHX SOUNDING SHOWS A CONTINUATION OF THE DRY AIRMASS AT THE SFC...ALONG
WITH CURRENT REGIONAL DEWPOINT DEPRESSION TRENDS WELL OVER 5 DEGREES...THAT
RAINFALL WILL BE ISO AT BEST AND MAY NOT EVEN REACH THE GROUND...AND COULD
EVEN BE MOSTLY SPRINKLE IN NATURE. THRU THE REMAINDER OF THE MORNING HRS HAVE
INTRODUCED A SLIGHT CHANCE FOR LOCATIONS GENERALLY W OF I-65 AND FOR THE
AFTERNOON HRS FOR LOCATIONS E OF I-65. IF CLOUDS DO NOT CLEAR THIS LATE
AFTERNOON AS EXPECTED...MIGHT ALSO HAVE TO LOWER HIGH TEMPS...BUT AT THIS
TIME WILL MONITOR FOR POSSIBLE FUTURE UPDATE.
31
PREV DISCUSSION... /ISSUED 436 AM CDT TUE SEP 25 2012/
SHORT TERM...
THE WARM FRONT THAT WILL INFLUENCE WEATHER FOR MOST OF THE WEEK CONTINUES
TO MOVE NORTHEAST THIS MORNING AND IS CURRENTLY STRETCHING ACROSS THE
MID MISSISSIPPI VALLEY AND OHIO VALLEY. A FEW ASSOCIATED SHOWERS HAVE
BEEN MOVING SLOWLY OVER WESTERN KENTUCKY AND WESTERN TN THIS
MORNING. HRRR SHOWS THIS ACTIVITY PERSISTING AND MOVING INTO MIDDLE
TN LATER THIS MORNING. HOWEVER ANY PRECIP SHOULD REMAIN LIGHT AND
MAINLY IMPACT NORTHWESTERN MIDDLE TN. CLOUD COVER WILL INCREASE
TODAY WITH MAINLY HIGH AND MID CLOUDS MOVING IN AS THE FRONT
REMAINS STATIONARY TUESDAY NIGHT AND WEDNESDAY. DIDN`T VENTURE TOO FAR
FROM GUIDANCE AS FAR AS TEMPS GO. HIGHS WILL BE QUITE A BIT WARMER
TODAY THROUGH THURSDAY...AROUND THE MID 80S AS WE SIT IN THE WARM
SECTOR OF THE FRONT. NIGHT TIME LOWS EXPECTED TO BE IN THE LOW 60S
WITH AREAS ALONG THE PLATEAU IN THE UPPER 50S. BEST PRECIP CHANCES
WILL REMAIN NORTH OF THE MIDSTATE BUT KEPT SLIGHT CHANCE POPS IN
THE PICTURE FOR THE NORTHERN COUNTIES FROM WEDNESDAY MORNING
THROUGH THURSDAY NIGHT.
LONG TERM...
MODELS CAN`T SEEM TO AGREE ON THE MOVEMENT OF THE FRONT TO THE
NORTH. THE NAM BRINGS THE FRONT DOWN TOWARD THE NORTHWESTERN
COUNTIES ON THURSDAY WHILE THE GFS KEEPS THE FRONT TO THE NORTH
OF THE MID- STATE UNTIL FRIDAY NIGHT. LEANED TOWARD THE GFS
SOLUTION, WITH CHANCE POPS MAKING AN APPEARANCE FRIDAY MORNING
ALONG THE NORTHERN PORTION OF OUR AREA AND INCREASING IN COVERAGE
AS SATURDAY APPROACHES. MODELS DO AGREE THAT THIS WEEKEND WILL BE
WET AS AN UPPER TROUGH DEEPENS OVER THE SOUTHEAST WITH THE UPPER
LOW MOVING TO THE WEST OF TN. KEPT CHANCE POPS THROUGHOUT THE
WEEKEND. THEN RAIN CHANCES DECREASES FROM WEST TO EAST AS THE MAIN
MOISTURE AXIS MOVES SLIGHTLY EAST MONDAY. WENT SLIGHTLY COOLER
THAN GUIDANCE ON THE TEMPS IN THE LONG TERM.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1200 PM CDT TUE SEP 25 2012
.DISCUSSION...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO LOWER HIGH TEMPS BY
A COUPLE OF DEGREES ACROSS LOCATIONS W OF THE PLATEAU FOR THIS AFTERNOON
AND TO ADDRESS MOCLDY SKY CONDTIONS ACROSS MOST LOCATIONS FOR THIS
AFTERNOON TOO.
&&
.PREV DISCUSSION.../ISSUED 1026 AM CDT TUE SEP 25 2012/
UPDATE...
WITH MOST CONVECTIVE ACTIVITY MOVING W TO OUR N ACROSS CNTRL AND NOW
INTO ERN KY...AND PER REGIONAL SATELLITE...RADAR MOSAICS...AND SFC OBS...
BELIEVE THAT WITH QUASI ZONAL FLOW PATTERN ALOFT...THE MID STATE SHOULD
GENERALLY ONLY EXPERIENCE AN INCREASING CLOUDINESS TREND THRU THE REMAINDER
OF THE MORNING HRS W THRU THE EARLY AFTERNOON HRS E...WITH CLRING POSSIBLE
ACROSS THE ENTIRE MID STATE BY THE LATE AFTERNOON HRS. BEST INSTABILITY
SHOULD REMAIN TO OUR N...AND BELIEVE IF ANY RAINFALL DOES OCCUR...AS 12Z
KOHX SOUNDING SHOWS A CONTINUATION OF THE DRY AIRMASS AT THE SFC...ALONG
WITH CURRENT REGIONAL DEWPOINT DEPRESSION TRENDS WELL OVER 5 DEGREES...THAT
RAINFALL WILL BE ISO AT BEST AND MAY NOT EVEN REACH THE GROUND...AND COULD
EVEN BE MOSTLY SPRINKLE IN NATURE. THRU THE REMAINDER OF THE MORNING HRS HAVE
INTRODUCED A SLIGHT CHANCE FOR LOCATIONS GENERALLY W OF I-65 AND FOR THE
AFTERNOON HRS FOR LOCATIONS E OF I-65. IF CLOUDS DO NOT CLEAR THIS LATE
AFTERNOON AS EXPECTED...MIGHT ALSO HAVE TO LOWER HIGH TEMPS...BUT AT THIS
TIME WILL MONITOR FOR POSSIBLE FUTURE UPDATE.
PREV DISCUSSION.../ISSUED 535 AM CDT TUE SEP 25 2012/
AVIATION 12Z DISCUSSION...
COLD FRONT WILL REMAIN STALLED TO OUR NORTH THROUGH THE TAF PD.
ACTIVE SOUTHERN JET WILL TRANSPORT MOISTURE IN THE FORM OF
MID/HIGH LEVEL CLOUDINESS ACROSS THE TAF AREAS. OTW...VSBYS NOT
EXPECTED TO BE A PROBLEM AS TD DEPRESSIONS TO REMAIN ELEVATED
THROUGH 12Z WED.
PREV DISCUSSION... /ISSUED 436 AM CDT TUE SEP 25 2012/
SHORT TERM...
THE WARM FRONT THAT WILL INFLUENCE WEATHER FOR MOST OF THE WEEK CONTINUES
TO MOVE NORTHEAST THIS MORNING AND IS CURRENTLY STRETCHING ACROSS THE
MID MISSISSIPPI VALLEY AND OHIO VALLEY. A FEW ASSOCIATED SHOWERS HAVE
BEEN MOVING SLOWLY OVER WESTERN KENTUCKY AND WESTERN TN THIS
MORNING. HRRR SHOWS THIS ACTIVITY PERSISTING AND MOVING INTO MIDDLE
TN LATER THIS MORNING. HOWEVER ANY PRECIP SHOULD REMAIN LIGHT AND
MAINLY IMPACT NORTHWESTERN MIDDLE TN. CLOUD COVER WILL INCREASE
TODAY WITH MAINLY HIGH AND MID CLOUDS MOVING IN AS THE FRONT
REMAINS STATIONARY TUESDAY NIGHT AND WEDNESDAY. DIDN`T VENTURE TOO FAR
FROM GUIDANCE AS FAR AS TEMPS GO. HIGHS WILL BE QUITE A BIT WARMER
TODAY THROUGH THURSDAY...AROUND THE MID 80S AS WE SIT IN THE WARM
SECTOR OF THE FRONT. NIGHT TIME LOWS EXPECTED TO BE IN THE LOW 60S
WITH AREAS ALONG THE PLATEAU IN THE UPPER 50S. BEST PRECIP CHANCES
WILL REMAIN NORTH OF THE MIDSTATE BUT KEPT SLIGHT CHANCE POPS IN
THE PICTURE FOR THE NORTHERN COUNTIES FROM WEDNESDAY MORNING
THROUGH THURSDAY NIGHT.
LONG TERM...
MODELS CAN`T SEEM TO AGREE ON THE MOVEMENT OF THE FRONT TO THE
NORTH. THE NAM BRINGS THE FRONT DOWN TOWARD THE NORTHWESTERN
COUNTIES ON THURSDAY WHILE THE GFS KEEPS THE FRONT TO THE NORTH
OF THE MID- STATE UNTIL FRIDAY NIGHT. LEANED TOWARD THE GFS
SOLUTION, WITH CHANCE POPS MAKING AN APPEARANCE FRIDAY MORNING
ALONG THE NORTHERN PORTION OF OUR AREA AND INCREASING IN COVERAGE
AS SATURDAY APPROACHES. MODELS DO AGREE THAT THIS WEEKEND WILL BE
WET AS AN UPPER TROUGH DEEPENS OVER THE SOUTHEAST WITH THE UPPER
LOW MOVING TO THE WEST OF TN. KEPT CHANCE POPS THROUGHOUT THE
WEEKEND. THEN RAIN CHANCES DECREASES FROM WEST TO EAST AS THE MAIN
MOISTURE AXIS MOVES SLIGHTLY EAST MONDAY. WENT SLIGHTLY COOLER
THAN GUIDANCE ON THE TEMPS IN THE LONG TERM.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 82 60 89 61 / 20 10 10 10
CLARKSVILLE 83 59 87 59 / 20 10 20 20
CROSSVILLE 76 56 81 57 / 20 10 10 10
COLUMBIA 83 60 88 60 / 20 10 10 10
LAWRENCEBURG 82 58 87 58 / 20 05 10 10
WAVERLY 84 60 88 59 / 20 10 10 20
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1026 AM CDT TUE SEP 25 2012
.UPDATE...
WITH MOST CONVECTIVE ACTIVITY MOVING W TO OUR N ACROSS CNTRL AND NOW
INTO ERN KY...AND PER REGIONAL SATELLITE...RADAR MOSAICS...AND SFC OBS...
BELIEVE THAT WITH QUASI ZONAL FLOW PATTERN ALOFT...THE MID STATE SHOULD
GENERALLY ONLY EXPERIENCE AN INCREASING CLOUDINESS TREND THRU THE REMAINDER
OF THE MORNING HRS W THRU THE EARLY AFTERNOON HRS E...WITH CLRING POSSIBLE
ACROSS THE ENTIRE MID STATE BY THE LATE AFTERNOON HRS. BEST INSTABILITY
SHOULD REMAIN TO OUR N...AND BELIEVE IF ANY RAINFALL DOES OCCUR...AS 12Z
KOHX SOUNDING SHOWS A CONTINUATION OF THE DRY AIRMASS AT THE SFC...ALONG
WITH CURRENT REGIONAL DEWPOINT DEPRESSION TRENDS WELL OVER 5 DEGREES...THAT
RAINFALL WILL BE ISO AT BEST AND MAY NOT EVEN REACH THE GROUND...AND COULD
EVEN BE MOSTLY SPRINKLE IN NATURE. THRU THE REMAINDER OF THE MORNING HRS HAVE
INTRODUCED A SLIGHT CHANCE FOR LOCATIONS GENERALLY W OF I-65 AND FOR THE
AFTERNOON HRS FOR LOCATIONS E OF I-65. IF CLOUDS DO NOT CLEAR THIS LATE
AFTERNOON AS EXPECTED...MIGHT ALSO HAVE TO LOWER HIGH TEMPS...BUT AT THIS
TIME WILL MONITOR FOR POSSIBLE FUTURE UPDATE.
&&
.PREV DISCUSSION.../ISSUED 535 AM CDT TUE SEP 25 2012/
AVIATION 12Z DISCUSSION...
COLD FRONT WILL REMAIN STALLED TO OUR NORTH THROUGH THE TAF PD.
ACTIVE SOUTHERN JET WILL TRANSPORT MOISTURE IN THE FORM OF
MID/HIGH LEVEL CLOUDINESS ACROSS THE TAF AREAS. OTW...VSBYS NOT
EXPECTED TO BE A PROBLEM AS TD DEPRESSIONS TO REMAIN ELEVATED
THROUGH 12Z WED.
PREV DISCUSSION... /ISSUED 436 AM CDT TUE SEP 25 2012/
SHORT TERM...
THE WARM FRONT THAT WILL INFLUENCE WEATHER FOR MOST OF THE WEEK CONTINUES
TO MOVE NORTHEAST THIS MORNING AND IS CURRENTLY STRETCHING ACROSS THE
MID MISSISSIPPI VALLEY AND OHIO VALLEY. A FEW ASSOCIATED SHOWERS HAVE
BEEN MOVING SLOWLY OVER WESTERN KENTUCKY AND WESTERN TN THIS
MORNING. HRRR SHOWS THIS ACTIVITY PERSISTING AND MOVING INTO MIDDLE
TN LATER THIS MORNING. HOWEVER ANY PRECIP SHOULD REMAIN LIGHT AND
MAINLY IMPACT NORTHWESTERN MIDDLE TN. CLOUD COVER WILL INCREASE
TODAY WITH MAINLY HIGH AND MID CLOUDS MOVING IN AS THE FRONT
REMAINS STATIONARY TUESDAY NIGHT AND WEDNESDAY. DIDN`T VENTURE TOO FAR
FROM GUIDANCE AS FAR AS TEMPS GO. HIGHS WILL BE QUITE A BIT WARMER
TODAY THROUGH THURSDAY...AROUND THE MID 80S AS WE SIT IN THE WARM
SECTOR OF THE FRONT. NIGHT TIME LOWS EXPECTED TO BE IN THE LOW 60S
WITH AREAS ALONG THE PLATEAU IN THE UPPER 50S. BEST PRECIP CHANCES
WILL REMAIN NORTH OF THE MIDSTATE BUT KEPT SLIGHT CHANCE POPS IN
THE PICTURE FOR THE NORTHERN COUNTIES FROM WEDNESDAY MORNING
THROUGH THURSDAY NIGHT.
LONG TERM...
MODELS CAN`T SEEM TO AGREE ON THE MOVEMENT OF THE FRONT TO THE
NORTH. THE NAM BRINGS THE FRONT DOWN TOWARD THE NORTHWESTERN
COUNTIES ON THURSDAY WHILE THE GFS KEEPS THE FRONT TO THE NORTH
OF THE MID- STATE UNTIL FRIDAY NIGHT. LEANED TOWARD THE GFS
SOLUTION, WITH CHANCE POPS MAKING AN APPEARANCE FRIDAY MORNING
ALONG THE NORTHERN PORTION OF OUR AREA AND INCREASING IN COVERAGE
AS SATURDAY APPROACHES. MODELS DO AGREE THAT THIS WEEKEND WILL BE
WET AS AN UPPER TROUGH DEEPENS OVER THE SOUTHEAST WITH THE UPPER
LOW MOVING TO THE WEST OF TN. KEPT CHANCE POPS THROUGHOUT THE
WEEKEND. THEN RAIN CHANCES DECREASES FROM WEST TO EAST AS THE MAIN
MOISTURE AXIS MOVES SLIGHTLY EAST MONDAY. WENT SLIGHTLY COOLER
THAN GUIDANCE ON THE TEMPS IN THE LONG TERM.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
535 AM CDT TUE SEP 25 2012
.AVIATION 12Z DISCUSSION...
COLD FRONT WILL REMAIN STALLED TO OUR NORTH THROUGH THE TAF PD.
ACTIVE SOUTHERN JET WILL TRANSPORT MOISTURE IN THE FORM OF
MID/HIGH LEVEL CLOUDINESS ACROSS THE TAF AREAS. OTW...VSBYS NOT
EXPECTED TO BE A PROBLEM AS TD DEPRESSIONS TO REMAIN ELEVATED
THROUGH 12Z WED.
&&
.PREV DISCUSSION... /ISSUED 436 AM CDT TUE SEP 25 2012/
SHORT TERM...
THE WARM FRONT THAT WILL INFLUENCE WEATHER FOR MOST OF THE WEEK CONTINUES
TO MOVE NORTHEAST THIS MORNING AND IS CURRENTLY STRETCHING ACROSS THE
MID MISSISSIPPI VALLEY AND OHIO VALLEY. A FEW ASSOCIATED SHOWERS HAVE
BEEN MOVING SLOWLY OVER WESTERN KENTUCKY AND WESTERN TN THIS
MORNING. HRRR SHOWS THIS ACTIVITY PERSISTING AND MOVING INTO MIDDLE
TN LATER THIS MORNING. HOWEVER ANY PRECIP SHOULD REMAIN LIGHT AND
MAINLY IMPACT NORTHWESTERN MIDDLE TN. CLOUD COVER WILL INCREASE
TODAY WITH MAINLY HIGH AND MID CLOUDS MOVING IN AS THE FRONT
REMAINS STATIONARY TUESDAY NIGHT AND WEDNESDAY. DIDN`T VENTURE TOO FAR
FROM GUIDANCE AS FAR AS TEMPS GO. HIGHS WILL BE QUITE A BIT WARMER
TODAY THROUGH THURSDAY...AROUND THE MID 80S AS WE SIT IN THE WARM
SECTOR OF THE FRONT. NIGHT TIME LOWS EXPECTED TO BE IN THE LOW 60S
WITH AREAS ALONG THE PLATEAU IN THE UPPER 50S. BEST PRECIP CHANCES
WILL REMAIN NORTH OF THE MIDSTATE BUT KEPT SLIGHT CHANCE POPS IN
THE PICTURE FOR THE NORTHERN COUNTIES FROM WEDNESDAY MORNING
THROUGH THURSDAY NIGHT.
LONG TERM...
MODELS CAN`T SEEM TO AGREE ON THE MOVEMENT OF THE FRONT TO THE
NORTH. THE NAM BRINGS THE FRONT DOWN TOWARD THE NORTHWESTERN
COUNTIES ON THURSDAY WHILE THE GFS KEEPS THE FRONT TO THE NORTH
OF THE MID- STATE UNTIL FRIDAY NIGHT. LEANED TOWARD THE GFS
SOLUTION, WITH CHANCE POPS MAKING AN APPEARANCE FRIDAY MORNING
ALONG THE NORTHERN PORTION OF OUR AREA AND INCREASING IN COVERAGE
AS SATURDAY APPROACHES. MODELS DO AGREE THAT THIS WEEKEND WILL BE
WET AS AN UPPER TROUGH DEEPENS OVER THE SOUTHEAST WITH THE UPPER
LOW MOVING TO THE WEST OF TN. KEPT CHANCE POPS THROUGHOUT THE
WEEKEND. THEN RAIN CHANCES DECREASES FROM WEST TO EAST AS THE MAIN
MOISTURE AXIS MOVES SLIGHTLY EAST MONDAY. WENT SLIGHTLY COOLER
THAN GUIDANCE ON THE TEMPS IN THE LONG TERM.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
436 AM CDT TUE SEP 25 2012
.SHORT TERM...
THE WARM FRONT THAT WILL INFLUENCE WEATHER FOR MOST OF THE WEEK CONTINUES
TO MOVE NORTHEAST THIS MORNING AND IS CURRENTLY STRETCHING ACROSS THE
MID MISSISSIPPI VALLEY AND OHIO VALLEY. A FEW ASSOCIATED SHOWERS HAVE
BEEN MOVING SLOWLY OVER WESTERN KENTUCKY AND WESTERN TN THIS
MORNING. HRRR SHOWS THIS ACTIVITY PERSISTING AND MOVING INTO MIDDLE
TN LATER THIS MORNING. HOWEVER ANY PRECIP SHOULD REMAIN LIGHT AND
MAINLY IMPACT NORTHWESTERN MIDDLE TN. CLOUD COVER WILL INCREASE
TODAY WITH MAINLY HIGH AND MID CLOUDS MOVING IN AS THE FRONT
REMAINS STATIONARY TUESDAY NIGHT AND WEDNESDAY. DIDN`T VENTURE TOO FAR
FROM GUIDANCE AS FAR AS TEMPS GO. HIGHS WILL BE QUITE A BIT WARMER
TODAY THROUGH THURSDAY...AROUND THE MID 80S AS WE SIT IN THE WARM
SECTOR OF THE FRONT. NIGHT TIME LOWS EXPECTED TO BE IN THE LOW 60S
WITH AREAS ALONG THE PLATEAU IN THE UPPER 50S. BEST PRECIP CHANCES
WILL REMAIN NORTH OF THE MIDSTATE BUT KEPT SLIGHT CHANCE POPS IN
THE PICTURE FOR THE NORTHERN COUNTIES FROM WEDNESDAY MORNING
THROUGH THURSDAY NIGHT.
.LONG TERM...
MODELS CAN`T SEEM TO AGREE ON THE MOVEMENT OF THE FRONT TO THE
NORTH. THE NAM BRINGS THE FRONT DOWN TOWARD THE NORTHWESTERN
COUNTIES ON THURSDAY WHILE THE GFS KEEPS THE FRONT TO THE NORTH
OF THE MID- STATE UNTIL FRIDAY NIGHT. LEANED TOWARD THE GFS
SOLUTION, WITH CHANCE POPS MAKING AN APPEARANCE FRIDAY MORNING
ALONG THE NORTHERN PORTION OF OUR AREA AND INCREASING IN COVERAGE
AS SATURDAY APPROACHES. MODELS DO AGREE THAT THIS WEEKEND WILL BE
WET AS AN UPPER TROUGH DEEPENS OVER THE SOUTHEAST WITH THE UPPER
LOW MOVING TO THE WEST OF TN. KEPT CHANCE POPS THROUGHOUT THE
WEEKEND. THEN RAIN CHANCES DECREASES FROM WEST TO EAST AS THE MAIN
MOISTURE AXIS MOVES SLIGHTLY EAST MONDAY. WENT SLIGHTLY COOLER
THAN GUIDANCE ON THE TEMPS IN THE LONG TERM.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 84 60 86 62 / 10 10 10 10
CLARKSVILLE 85 61 86 61 / 30 10 20 20
CROSSVILLE 76 57 80 57 / 10 10 10 10
COLUMBIA 85 60 87 60 / 10 10 10 10
LAWRENCEBURG 84 59 87 60 / 10 05 10 10
WAVERLY 86 61 86 61 / 30 10 10 20
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1002 PM CDT WED SEP 26 2012
.UPDATE...
HAVE REMOVED SEVERE THUNDERSTORM WATCH FROM CIMARRON...DALLAM...
HARTLEY...AND SHERMAN COUNTIES FROM SEVERE THUNDERSTORM WATCH 653 AS
THE ATMOSPHERE HAS STABILIZED WITH TEMPS COOLING DOWN INTO THE MID TO
UPPER 50S. COMPLEX OF STRONG TO SEVERE THUNDERSTORMS CONTINUES TO
MOVE ACROSS THE CENTRAL AND EASTERN OKLAHOMA PANHANDLE AND AN OUTFLOW
BOUNDARY WAS RACING SOUTHWARD FROM THESE STORMS. HAVE OPTED TO LEAVE
THE WATCH IN EFFECT FOR THE REMAINDER OF THE PANHANDLES UNTIL 11 PM
AS THIS OUTFLOW BOUNDARY MAY PROVIDE A FOCUS FOR STORMS. HAVE ALSO
ADJUSTED LOW TEMPS DOWN A FEW DEGREES IN THE NORTHWEST ZONES. UPDATED
TEXT PRODUCTS HAVE BEEN SENT.
CLK
&&
.PREV DISCUSSION... /ISSUED 718 PM CDT WED SEP 26 2012/
AVIATION...
/00Z TAFS/ COMPLEX AVIATION FORECAST SHAPING UP OVER THE NEXT 24
HOURS. ONGOING CONVECTION IS CURRENTLY NORTH AND WEST OF KGUY/KDHT
AND WELL EAST OF THE KAMA TERMINAL. CURRENT RADAR REFLECTIVITY
IMAGERY SHOWS ADDITIONAL DEVELOPMENT IN EASTERN NEW MEXICO WHICH THE
18Z TTU WRF AND 21Z HRRR ARE DEPICTING THIS INCREASING IN COVERAGE
AS IT MOVES ACROSS THE PANHANDLES LATER TONIGHT. HAVE KEPT IN PREVIOUS
MENTION OF -SHRA AS COOLING BOUNDARY LAYER TEMPS SHOULD LIMIT THE
INSTABILITY AND THUS LOWER THE CHANCES FOR THUNDER DEVELOPMENT. LOW
CLOUDS AND FOG ARE POSSIBLE AT KGUY/KDHT THURSDAY MORNING WHERE A
LITTLE BETTER LOW LEVEL MOISTURE WILL RESIDE. HOWEVER HAVE KEPT
CONDITIONS AT MVFR AS CONFIDENCE IS NOT TOO HIGH THAT WORSENING
CONDITIONS WILL DEVELOP. HAVE KEPT A VFR FORECAST IN AT KAMA BUT MAY
HAVE TO AMEND IF TRENDS SUGGEST CIGS AND/OR VISBYS LOWERING BELOW
MVFR. STORMS CAN DEVELOP AT THE TERMINALS THURSDAY BUT HAVE OPTED TO
LEAVE MENTION OUT OF THE TAFS DUE TO LOW CONFIDENCE ON TIMING AND
WHERE STORMS WILL DEVELOP.
CLK
PREV DISCUSSION... /ISSUED 351 PM CDT WED SEP 26 2012/
DISCUSSION...
THROUGH TONIGHT: A RATHER COMPLICATED AND SOMEWHAT LOW CONFIDENCE
FORECAST HAS EVOLVED TODAY. A WEAK SURFACE TROUGH CURRENTLY STRETCHES
FROM THE SOUTHERN TEXAS PANHANDLE TO NEAR THE RED RIVER. IN THE
UPPER-LEVELS A CLOSED LOW CONTINUES TO SPIN OVER THE WESTERN COLORADO
WITH A SUBTLE SHORTWAVE TROUGH...EJECTING OUT OF THIS LOW...NOW
APPROACHING EASTERN NEW MEXICO. LARGE SCALE FORCING FOR ASCENT WILL
BE ON THE INCREASE THROUGH THIS EVENING...AND WE EXPECT ISOLATED TO
WIDELY SCATTERED CONVECTION TO INITIATE SOUTH AND WEST OF A BOISE CITY
TO SHAMROCK LINE THROUGH 7 PM. A LOOSELY ORGANIZED COMPLEX OF STORMS
MAY EVOLVE AFTER 11 PM ALONG AND EAST OF A GUYMON TO CLARENDON LINE
AND STEADILY MARCH EASTWARD OVERNIGHT. BASED ON THIS SCENARIO...WE
THINK THE HIGHEST SEVERE WEATHER CHANCES WILL BE THROUGH MIDNIGHT.
MIXED LAYER CAPE VALUES WILL BE UP TO 2000 J/KG IN THE SOUTHEAST WITH
EFFECTIVE BULK SHEAR VALUES UP TO 45 KT ACROSS MOST OF THE AREA. AS A
RESULT...LARGE HAIL UP TO THE SIZE OF HALF DOLLARS AND DAMAGING
WINDS IN EXCESS OF 60 MPH WILL BE THE PRIMARY HAZARDS. THE HAIL
THREAT WILL LIKELY BE HIGHEST ACROSS THE SOUTHEAST TEXAS PANHANDLE
WHERE THE AIR MASS IS MOST UNSTABLE AND HAIL GROWTH CAPE VALUES WILL
BE AS HIGH AS 600 J/KG. BELIEVE THE ATMOSPHERE WILL BE WORKED OVER
ENOUGH OVERNIGHT THAT THIS MAY LIMIT THE COVERAGE OF ADDITIONAL
THUNDERSTORMS. THEREFORE...WE LOWERED POPS FOR THE OVERNIGHT HOURS.
THURSDAY-THURSDAY NIGHT: ANOTHER TRICKY FORECAST IS IN STORE FOR
TOMORROW AND THE BEST THUNDERSTORM CHANCES WILL LARGELY DEPEND ON
WHERE THE SURFACE FRONT SETS UP. THE NAM AND ECMWF KEEP THE FRONT
JUST NORTH OF INTERSTATE 40 WHILE THE GFS AND GGEM KEEP THE FRONT
ACROSS THE NORTHERN TEXAS PANHANDLE. EXTENSIVE LOW CLOUDS WILL ALSO
COMPLICATE HIGH TEMPERATURES DURING THE AFTERNOON WITH HIGHS NEAR 70
EXPECTED IN THE NORTHWEST AND MID 70S IN THE SOUTHEAST. THESE LOW
CLOUDS WILL ALSO HAVE A LARGE IMPACT ON HOW UNSTABLE THE ATMOSPHERE
CAN BECOME. IF THE LOW CLOUDS ARE STUBBORN TO BREAK...THIS COULD LEAD
TO A VERY MARGINAL SEVERE WEATHER EVENT. AT THIS TIME..WE THINK THERE
WILL BE ENOUGH BREAKS IN THE CLOUDS TO DESTABILIZE THE ATMOSPHERE
SUFFICIENTLY FOR SEVERE STORMS. IN FACT...A FEW SEVERE STORMS CANNOT
BE RULED OUT JUST ABOUT ANYWHERE DURING THE AFTERNOON AND
EVENING...BUT THE HIGHER PROBABILITIES LOOK TO EXIST SOUTH OF A
DALHART TO CANADIAN LINE. DEEP LAYER BULK SHEAR VALUES WILL RANGE
BETWEEN 30 AND 40 KT ALONG WITH MIXED LAYER CAPE VALUES UP TO 1000
J/KG. AS A RESULT...LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY
HAZARDS. MORE WIDESPREAD RAIN CHANCES LOOK TO EVOLVE DURING THE LATE
EVENING AND OVERNIGHT HOURS. LOCALLY HEAVY RAIN WILL ALSO CONTINUE TO
BE A CONCERN.
FRIDAY-WEDNESDAY: THUNDERSTORMS CHANCES WILL CONTINUE THROUGH SUNDAY
NIGHT BEFORE DRIER CONDITIONS RETURN FOR EARLY NEXT WEEK. NO SEVERE
WEATHER IS ANTICIPATED DURING THIS TIME FRAME AS THE ENVIRONMENT
SHOULD BE WEAKLY UNSTABLE ALONG WITH POOR DEEP LAYER WIND SHEAR IN
PLACE. TEMPERATURES WILL BE NEAR TO BELOW NORMAL FRIDAY AND SATURDAY
BEFORE A WARMING TREND BEGINS SUNDAY.
JACKSON
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
THROUGH WEDNESDAY AS 20-FOOT WINDS WILL REMAIN BELOW 15 MPH AND/OR
RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE 20 PERCENT.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
718 PM CDT WED SEP 26 2012
.AVIATION...
/00Z TAFS/ COMPLEX AVIATION FORECAST SHAPING UP OVER THE NEXT 24
HOURS. ONGOING CONVECTION IS CURRENTLY NORTH AND WEST OF KGUY/KDHT
AND WELL EAST OF THE KAMA TERMINAL. CURRENT RADAR REFLECTIVITY
IMAGERY SHOWS ADDITIONAL DEVELOPMENT IN EASTERN NEW MEXICO WHICH THE
18Z TTU WRF AND 21Z HRRR ARE DEPICTING THIS INCREASING IN COVERAGE
AS IT MOVES ACROSS THE PANHANDLES LATER TONIGHT. HAVE KEPT IN PREVIOUS
MENTION OF -SHRA AS COOLING BOUNDARY LAYER TEMPS SHOULD LIMIT THE
INSTABILITY AND THUS LOWER THE CHANCES FOR THUNDER DEVELOPMENT. LOW
CLOUDS AND FOG ARE POSSIBLE AT KGUY/KDHT THURSDAY MORNING WHERE A
LITTLE BETTER LOW LEVEL MOISTURE WILL RESIDE. HOWEVER HAVE KEPT
CONDITIONS AT MVFR AS CONFIDENCE IS NOT TOO HIGH THAT WORSENING
CONDITIONS WILL DEVELOP. HAVE KEPT A VFR FORECAST IN AT KAMA BUT MAY
HAVE TO AMEND IF TRENDS SUGGEST CIGS AND/OR VISBYS LOWERING BELOW
MVFR. STORMS CAN DEVELOP AT THE TERMINALS THURSDAY BUT HAVE OPTED TO
LEAVE MENTION OUT OF THE TAFS DUE TO LOW CONFIDENCE ON TIMING AND
WHERE STORMS WILL DEVELOP.
CLK
&&
.PREV DISCUSSION... /ISSUED 351 PM CDT WED SEP 26 2012/
DISCUSSION...
THROUGH TONIGHT: A RATHER COMPLICATED AND SOMEWHAT LOW CONFIDENCE
FORECAST HAS EVOLVED TODAY. A WEAK SURFACE TROUGH CURRENTLY STRETCHES
FROM THE SOUTHERN TEXAS PANHANDLE TO NEAR THE RED RIVER. IN THE
UPPER-LEVELS A CLOSED LOW CONTINUES TO SPIN OVER THE WESTERN COLORADO
WITH A SUBTLE SHORTWAVE TROUGH...EJECTING OUT OF THIS LOW...NOW
APPROACHING EASTERN NEW MEXICO. LARGE SCALE FORCING FOR ASCENT WILL
BE ON THE INCREASE THROUGH THIS EVENING...AND WE EXPECT ISOLATED TO
WIDELY SCATTERED CONVECTION TO INITIATE SOUTH AND WEST OF A BOISE CITY
TO SHAMROCK LINE THROUGH 7 PM. A LOOSELY ORGANIZED COMPLEX OF STORMS
MAY EVOLVE AFTER 11 PM ALONG AND EAST OF A GUYMON TO CLARENDON LINE
AND STEADILY MARCH EASTWARD OVERNIGHT. BASED ON THIS SCENARIO...WE
THINK THE HIGHEST SEVERE WEATHER CHANCES WILL BE THROUGH MIDNIGHT.
MIXED LAYER CAPE VALUES WILL BE UP TO 2000 J/KG IN THE SOUTHEAST WITH
EFFECTIVE BULK SHEAR VALUES UP TO 45 KT ACROSS MOST OF THE AREA. AS A
RESULT...LARGE HAIL UP TO THE SIZE OF HALF DOLLARS AND DAMAGING
WINDS IN EXCESS OF 60 MPH WILL BE THE PRIMARY HAZARDS. THE HAIL
THREAT WILL LIKELY BE HIGHEST ACROSS THE SOUTHEAST TEXAS PANHANDLE
WHERE THE AIR MASS IS MOST UNSTABLE AND HAIL GROWTH CAPE VALUES WILL
BE AS HIGH AS 600 J/KG. BELIEVE THE ATMOSPHERE WILL BE WORKED OVER
ENOUGH OVERNIGHT THAT THIS MAY LIMIT THE COVERAGE OF ADDITIONAL
THUNDERSTORMS. THEREFORE...WE LOWERED POPS FOR THE OVERNIGHT HOURS.
THURSDAY-THURSDAY NIGHT: ANOTHER TRICKY FORECAST IS IN STORE FOR
TOMORROW AND THE BEST THUNDERSTORM CHANCES WILL LARGELY DEPEND ON
WHERE THE SURFACE FRONT SETS UP. THE NAM AND ECMWF KEEP THE FRONT
JUST NORTH OF INTERSTATE 40 WHILE THE GFS AND GGEM KEEP THE FRONT
ACROSS THE NORTHERN TEXAS PANHANDLE. EXTENSIVE LOW CLOUDS WILL ALSO
COMPLICATE HIGH TEMPERATURES DURING THE AFTERNOON WITH HIGHS NEAR 70
EXPECTED IN THE NORTHWEST AND MID 70S IN THE SOUTHEAST. THESE LOW
CLOUDS WILL ALSO HAVE A LARGE IMPACT ON HOW UNSTABLE THE ATMOSPHERE
CAN BECOME. IF THE LOW CLOUDS ARE STUBBORN TO BREAK...THIS COULD LEAD
TO A VERY MARGINAL SEVERE WEATHER EVENT. AT THIS TIME..WE THINK THERE
WILL BE ENOUGH BREAKS IN THE CLOUDS TO DESTABILIZE THE ATMOSPHERE
SUFFICIENTLY FOR SEVERE STORMS. IN FACT...A FEW SEVERE STORMS CANNOT
BE RULED OUT JUST ABOUT ANYWHERE DURING THE AFTERNOON AND
EVENING...BUT THE HIGHER PROBABILITIES LOOK TO EXIST SOUTH OF A
DALHART TO CANADIAN LINE. DEEP LAYER BULK SHEAR VALUES WILL RANGE
BETWEEN 30 AND 40 KT ALONG WITH MIXED LAYER CAPE VALUES UP TO 1000
J/KG. AS A RESULT...LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY
HAZARDS. MORE WIDESPREAD RAIN CHANCES LOOK TO EVOLVE DURING THE LATE
EVENING AND OVERNIGHT HOURS. LOCALLY HEAVY RAIN WILL ALSO CONTINUE TO
BE A CONCERN.
FRIDAY-WEDNESDAY: THUNDERSTORMS CHANCES WILL CONTINUE THROUGH SUNDAY
NIGHT BEFORE DRIER CONDITIONS RETURN FOR EARLY NEXT WEEK. NO SEVERE
WEATHER IS ANTICIPATED DURING THIS TIME FRAME AS THE ENVIRONMENT
SHOULD BE WEAKLY UNSTABLE ALONG WITH POOR DEEP LAYER WIND SHEAR IN
PLACE. TEMPERATURES WILL BE NEAR TO BELOW NORMAL FRIDAY AND SATURDAY
BEFORE A WARMING TREND BEGINS SUNDAY.
JACKSON
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
THROUGH WEDNESDAY AS 20-FOOT WINDS WILL REMAIN BELOW 15 MPH AND/OR
RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE 20 PERCENT.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
223 PM CDT TUE SEP 25 2012
.SHORT TERM...TONIGHT AND WEDNESDAY
HIGH PRESSURE WAS BUILDING INTO WISCONSIN THIS AFTERNOON OUT OF
CANADA...RESULTING IN QUIET WEATHER. JUST A FEW FAIR WEATHER CU
DEVELOPED OVER NORTHERN WISCONSIN AND ALONG WITH LAKESHORE. THIS
AREA OF HIGH PRESSURE WILL CONTINUE TO PUSH INTO NORTHEAST WI
DURING THE SHORT TERM...WITH THE MAIN FORECAST CHALLENGES BEING
CLOUDS AND TEMPERATURES.
A 500MB SHORTWAVE WILL PASS OVER LAKE SUPERIOR OVERNIGHT INTO
WEDNESDAY...BRUSHING NORTHERN WISCONSIN AS IT DOES SO. WITH SFC
HIGH PRESSURE MOVING OVER WISCONSIN...DRY AIR AND A LACK OF
FORCING WILL PREVENT ANY PRECIP SO KEPT DRY FORECAST GOING.
MODELS HAVE BEEN STRUGGLING WITH CLOUDS WITH THIS FEATURE AS IT
MOVES THROUGH. CURRENT SAT ELITE AND RAP MODEL ANALYSIS SHOWS THAT
MOST OF THE MOISTURE ASSOCIATED WITH THE CLOUDS CURRENTLY IN
NORTHEAST MINNESOTA NEAR THE DIGGING SHORTWAVE IS CONFINED TO 925
AND 850MB...SO USED THIS INFORMATION FOR CLOUD FORECAST FOR
TONIGHT AND WEDNESDAY. CU FROM THIS AFTERNOON WILL DISSIPATE WITH
THE SUNSET OVER NORTHERN WI...BUT WILL LINGER NEAR THE LAKESHORE
WITH THE CONTINUED NE FLOW. THE NEXT AREA OF CLOUDS WILL MOVE INTO
NORTHERN WISCONSIN AFTER 06Z TONIGHT. CLOUDS WILL BE LIMITED AT
FIRST...BUT THEN SHOULD INCREASE IN COVERAGE TOMORROW...ESPECIALLY
DURING THE AFTERNOON...AS SUN AIDS IN CU DEVELOPMENT AND
SUFFICIENT 850MB MOISTURE OVERSPREADS THE AREA. NORTHERN WISCONSIN
SHOULD SEE THE MOST CLOUDS AS IT IS NEAREST TO THE PASSING
SHORTWAVE...WITH A MIX OF SUN AND CLOUDS ELSEWHERE.
DIDNT CHANGE MUCH TEMPERATURE-WISE FROM PREVIOUS FORECAST AS
NORTHWEST FLOW WILL KEEP THINGS COOLER THAN NORMAL ON WEDNESDAY.
WIDESPREAD FROST IS AGAIN EXPECTED IN NORTHERN WI WHERE GROWING
SEASON HAS ENDED. PATCHY FROST IS POSSIBLE IN CENTRAL WISCONSIN
TONIGHT...HOWEVER THINK TEMPS WILL BE SLIGHTLY TOO WARM FOR
WIDESPREAD FROST DEVELOPMENT.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY.
QUIET WEATHER PATTERN EXPECTED THROUGH THE PERIOD. MODELS CONTINUE
TO STRUGGLE WITH CLOSED UPPER LOW ACROSS THE EASTERN UNITED STATES
OVER THE WEEKEND. LATEST GFS IS FURTHER WEST THAN THE CANADIAN AND
THE 12Z LOW RES ECMWF IS FURTHER WEST THAN BOTH THE CANADIAN/GFS.
DID NOT RECEIVE THE 12Z HIGH ECMWF...THEREFORE WILL CONTINUE WITH A
DRY AND CLEAR TO PARTLY CLOUDY FORECAST FOR THE WEEKEND. IF ECMWF
TREND IS CORRECT...LATER SHIFT MAY NEED TO ADD MORE CLOUDS AND
MAYBE A SMALL CHANCE OF SHOWER OVER THE WEEKEND WITH ENERGY
PIVOTING AROUND THE UPPER LOW.
OTHERWISE...IT WILL BE SEASONABLE WITH LOWS IN THE 30S TO LOWER
TO MIDDLE 40S AND HIGHS IN THE 60S TO AROUND 70. DID LOWER MIN
TEMPERATURES A FEW DEGREES EACH NIGHT THROUGH THE WEEKEND...
ESPECIALLY IN THE TYPICAL COLD SPOTS NORTH AND WEST OF GREEN BAY
AND THE FOX CITES. ALSO RAISED MAX TEMPERATURES A FEW DEGREES ON
FRIDAY BASED ON 925MB TEMPERATURES AND EXPECTED DRY AIR MASS IN
PLACE.
&&
.AVIATION...VFR CONDITIONS WILL DOMINATED MOST OF THE REGION
TODAY INTO WEDNESDAY. PATCHY MVFR CIGS MAY PASS OVER PARTS OF
NORTHERN WISCONSIN TONIGHT INTO WEDNESDAY AS A WEAK SHORTWAVE
MOVES OVER LAKE SUPERIOR.
WOLF
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WOLF/ECKBERG
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
330 AM EDT THU SEP 27 2012
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN OVERALL LESS AMPLIFIED
UPPER LEVEL PATTERN...WITH MAINLY ZONAL FLOW IN PLACE OVER THE
SOUTHEASTERN STATES. MAIN LONGWAVE TROUGH WITHIN THE NORTHERN STREAM
FLOW IS LOCATED OVER EASTERN CANADA/NEW ENGLAND WITH AN AXIS WHICH
IS QUICKLY PIVOTING EASTWARD TOWARD THE CANADIAN MARITIME REGION.
FAIRLY POTENT SHORTWAVE ENERGY REMAIN IN PLACE OVER THE
INTER-MOUNTAIN WEST EARLY THIS MORNING...BUT IS EXPECTED TO SHEAR
OUT AND DISSIPATE AS IT BEGINS TO EJECT EASTWARD LATER TODAY/TONIGHT.
AT THE SURFACE...SURFACE RIDGE HAS MOVED LITTLE IN THE PAST 24 HOURS
AND REMAINS ALIGNED FROM THE CAROLINA COAST TO NORTHERN GA/AL. OUR
FORECAST AREA/FL PENINSULA REMAIN WITHIN A MOIST EASTERLY FLOW
AROUND THE SOUTHERN PERIPHERY OF THE RIDGE WITH REGIONAL DEWPOINTS
BACK INTO THE LOWER 70S. VERY LITTLE TO MENTION EARLY THIS MORNING
ON REGIONAL RADARS AS THERE IS LITTLE IN THE WAY OF SYNOPTIC
INFLUENCE FOR LIFT CURRENTLY OVERHEAD. SIMILAR TO TUESDAY
NIGHT...THE DEEP MOISTURE IS EXPECTED TO LEAD TO AREAS OF FOG BY
DAWN. THE FACT THAT WE ARE SEEING A SIGNIFICANT THINNING OF THE
UPPER LEVEL CIRRUS EARLY THIS MORNING WILL ONLY HELP TO FURTHER
PROMOTE THE FOG FORMATION.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY/TONIGHT...OVERALL PATTERN LOOKS VERY SIMILAR TO WEDNESDAY WITH
CONTINUED EASTERLY FLOW AND A FAIRLY MOIST MIDDLE AND LOWER LEVEL
PROFILE. WITHOUT ANY SIGNIFICANT SYNOPTIC FEATURES TO ENHANCE LIFT
AND LITTLE IF ANY SEA-BREEZE INFLUENCE...SHOWERS/STORMS SHOULD BE
WIDELY SCATTERED IN NATURE ONCE AGAIN. HAVE GONE WITH A GENERAL 30%
POP...WITH THE EARLIEST TIMING FOR SHOWERS OVER INLAND AREAS.
INITIAL CONVECTION SHOULD BE OVER NEAR THE EAST COAST AND PROPAGATE
INLAND WITH TIME. LATER DAY CONVECTION CLOSER TO THE WEST COAST WILL
FIRE ALONG OUTFLOW BOUNDARIES FROM THIS FIRST WAVE OF SHOWERS THAT
FURTHER PROPAGATE WESTWARD WITHIN THE SYNOPTIC FLOW. OF NOTE...MANY
OF THE CONVECTION ALLOWING HIGH RESOLUTION GUIDANCE MEMBERS...
INCLUDING THE LOCAL 4KM WRF-ARW...SUGGEST THE BEST COVERAGE OF
SHOWERS DURING THE AFTERNOON WILL BE OVER THE NATURE COAST ZONES.
WILL LET THE NEXT SHIFT EVALUATE LATER GUIDANCE SUITES BEFORE
POTENTIALLY RAISING POPS TO THE NORTH OF I-4. A BIT MORE INSOLATION
EXPECTED TODAY...ESPECIALLY THIS MORNING WITH LESS IN THE WAY OF
UPPER LEVEL CIRRUS. THIS ENHANCED SOLAR RADIATION SHOULD ALLOW MORE
LOCATIONS TO REACH THE LOWER 90S FOR HIGH TEMPERATURES. ANY
LINGERING SHOWERS AND STORMS WILL DISSIPATE WITHIN A FEW HOURS OF
SUNSET RESULTING IN A GENERALLY DRY FORECAST OVERNIGHT AND EARLY
FRIDAY MORNING.
FRIDAY...RIDGE CENTER TO OUR NORTH WILL BE WEAKENING WITH A
RESULTING WEAKENING OF THE LOCAL GRADIENT. FOR THIS REASON WE MAY
SEE THE FIRST REAL DEFINED SEA-BREEZE CIRCULATION IN SEVERAL DAYS
DEVELOP NEAR THE COAST DURING THE AFTERNOON. FRIDAY LOOKS SEASONABLE
IN TERMS OF BOTH TEMPERATURES AND RAIN CHANCES...AND WILL NOT
DEVIATE MUCH FROM THE MAV NUMBERS.
SATURDAY...ANOTHER SEASONABLE DAY ON TAP WITH TEMPS NEAR 90 FOR MOST
LOCATIONS AND WIDELY SCT MAINLY AFTERNOON/EVENING STORMS. WHILE NOT
DIRECTLY INFLUENCING OUR WEATHER QUITE YET DURING THE FIRST HALF OF
THE WEEKEND...WE WILL BEGIN TO SEE THE FIRST STAGES OF AN EXPECTED
SIGNIFICANT AMPLIFICATION TO THE PATTERN DEVELOPING OVER THE EASTERN
CONUS. THIS DEVELOPING PATTERN WILL BE A SIGNIFICANT PLAYER IN OUR
WEATHER HEADING INTO NEXT WEEK. MORE ON ALL THIS IN THE LONG TERM
DISCUSSION BELOW.
&&
.LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)...
MODELS HAVE COME INTO MUCH BETTER AGREEMENT REGARDING THE EASTERN
U.S. TROUGH AND ASSOCIATED SURFACE FEATURES. THAT SAID...THERE ARE
DIFFERENCES FROM WHAT WE SAW YESTERDAY...AND STILL TIME FOR THE
MODELS TO CHANGE THEIR SOLUTIONS SEVERAL TIMES BETWEEN NOW AND THE
WEEKEND. ONE NOTABLE TREND IS THAT THE 500MB CUTOFF LOW HAS BEEN
FARTHER WEST WITH EACH RUN AND IS NOW NEAR THE TEXAS/LOUISIANA
BORDER LATE TUESDAY. OUR LOWEST 500MB HEIGHTS ARE ON MONDAY...THEN
MODELS BRING THE ATLANTIC RIDGE SMARTLY WESTWARD BY WEDNESDAY. THAT
WOULD BLOCK ANY EASTWARD PROGRESSION OF THE FRONT AND LIKELY EVEN
PUSH IT BACK TO THE NORTHWEST. BOTH THE 00Z GFS AND THE 12Z ECMWF
SHOW THE SURFACE RIDGE BUILDING BACK ACROSS THE REGION...TURNING OUR
WINDS FROM SOUTHERLY EARLY IN THE WEEK BACK TO SOUTHEASTERLY BY
MID-WEEK. THERE IS STILL A CHANCE OF A PERIOD OF WET WEATHER
BEGINNING LATE SUNDAY AND EXTENDING THROUGH TUESDAY. THE UPPER-LEVEL
TROUGH WILL BE THE MOST PRONOUNCED AND FARTHEST EAST DURING THIS
TIME WITH THE SURFACE BOUNDARY ALONG THE NORTHERN GULF COAST. BY
WEDNESDAY WE RETURN TO A SUMMER-TIME PATTERN MORE TYPICAL OF AUGUST
WITH HIGH MOISTURE CONTENT BUT VERY LITTLE SYNOPTIC SCALE LIFT. THE
GFS FORECASTS A RIBBON OF VERY HIGH PRECIPITABLE WATERS...IN EXCESS
OF 2.25 INCHES...ASSOCIATED WITH A SURFACE TROUGH OR PERHAPS A
TROPICAL WAVE MOVING NORTHWEST ACROSS THE REGION ON WEDNESDAY. SINCE
THIS IS DAY 7...I PREFER NOT TO STRAY TOO FAR FROM CLIMATOLOGY
REGARDING RAIN CHANCES THIS FAR OUT.
TEMPERATURES WILL RUN SEVERAL DEGREES ABOVE NORMAL DURING THIS
PERIOD...ESPECIALLY IF THE CURRENT MODEL TREND CONTINUES...KEEPING
MOST OF THE SYNOPTIC SCALE LIFT TO OUR NORTHWEST.
&&
.AVIATION...
MAINLY VFR BUT CAN NOT RULE OUT SOME PATCHY FOG AND LOW CLOUDS AGAIN
AROUND SUNRISE. THE MOST LIKELY LOCATIONS WOULD BE LAL AND PGD BUT
SOME LOW CLOUDS COULD ALSO MOVE INTO TPA...PIE AND SRQ.
&&
.MARINE...
THE HIGH PRESSURE RIDGE TO OUR NORTH WILL SLOWLY WEAKEN DURING THE
NEXT COUPLE OF DAYS ALLOWING THE LOCAL GRADIENT TO ALSO WEAKEN.
WINDS AND SEAS ARE EXPECTED TO REMAIN WELL BELOW HEADLINE CRITERIA
THROUGH AT LEAST THE FIRST HALF OF THE UPCOMING WEEKEND.
&&
.FIRE WEATHER...
ABUNDANT ATLANTIC MOISTURE ARRIVING ON EASTERLY FLOW WILL KEEP
RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS THROUGH THE
UPCOMING WEEKEND. NO SIGNIFICANT FIRE WEATHER PROBLEMS ARE
ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 74 90 75 / 30 20 30 20
FMY 90 73 90 73 / 30 20 40 20
GIF 91 72 91 70 / 30 10 30 10
SRQ 89 72 89 72 / 30 20 30 20
BKV 91 69 90 68 / 30 20 30 10
SPG 89 76 89 76 / 30 20 30 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1148 PM CDT WED SEP 26 2012
.DISCUSSION...
ISSUED 859 PM CDT WED SEP 26 2012
NEARLY STATIONARY FRONTAL BOUNDARY STILL BISECTING THE FORECAST
AREA THIS EVENING...ALTHOUGH THE BULK OF THE PRECIPITATION FALLING
IS WELL SOUTH OF THE BOUNDARY. DO NOT EXPECT SIGNIFICANT RAINFALL
FOR THE REST OF THE NIGHT...BUT CAN NOT DISCOUNT THE RISK FOR SOME
REDEVELOPMENT AS A VIGOROUS WAVE CURRENTLY CROSSING MISSOURI
INTERACTS WITH THE FRONT. THE PRESENCE OF THE FRONT...LIGHT WINDS
IN ITS VICINITY...AND GRADUALLY CLEARING SKIES FROM THE NORTH POSE
A FOG THREAT TONIGHT. HOWEVER...THE FOG THREAT SHOULD BE FURTHER
SOUTH TONIGHT THAN IT WAS LAST NIGHT...MOST LIKELY CLOSER TO I-70
CORRIDOR WHERE MORE SIGNIFICANT RAINS HAVE FALLEN LATELY AND
SURFACE DEW POINTS WILL BE LAST TO START DROPPING.
GOING FORECAST IS IN GOOD SHAPE OVERALL. MAIN CHANGE PLANNED IS TO
REDUCE POP AND THUNDER MENTION OVERNIGHT. OTHERWISE...MINOR
CHANGES ARE PLANNED FOR THE LATEST TRENDS.
BAK
&&
.AVIATION...
ISSUED 1148 PM CDT WED SEP 26 2012
A FRONTAL BOUNDARY IS VERY SLOWLY SETTLING SOUTH OF THE CENTRAL
ILLINOIS TERMINALS THIS EVENING...WITH WEAK HIGH PRESSURE BUILDING
IN BEHIND IT. NORTHEAST WINDS BEHIND THE FRONT ARE USHERING DRIER
AIR INTO THE AREA...AND WILL EVENTUALLY RESULT IN CLEAR SKIES AND
A DISSIPATION OF ANY FOG. THIS CLEARING/DRYING TREND IS ALREADY
OCCURRING AT KPIA...BUT PERIODS OF MVFR CIGS/VSBYS ARE POSSIBLE A
THE REMAINING CENTRAL ILLINOIS TAF SITES FOR AT LEAST A FEW HOURS
LONGER. VFR CONDITIONS SHOULD PREVAIL AREAWIDE AFTER DAYBREAK
THURSDAY...AND LINGER THROUGH THE REST OF THE PERIOD.
BAK
&&
.PREV DISCUSSION...
ISSUED 221 PM CDT WED SEP 26 2012
RAIN CHANCES WILL PERSIST ACROSS SOUTH-CENTRAL ILLINOIS THROUGH
THURSDAY NIGHT...BEFORE A LONG STRETCH OF DRY WEATHER DEVELOPS
ACROSS THE ENTIRE REGION THROUGH NEXT WEEK.
SHORT TERM...TONIGHT THROUGH SATURDAY
19Z/2PM SURFACE ANALYSIS SHOWS A SLOW-MOVING COLD FRONT EXTENDING
FROM JUST SOUTH OF KIKK TO NEAR KUIN. TO THE NORTH OF THE
FRONT...WINDS HAVE BECOME NORTHERLY AND A DRIER AIRMASS IS
BEGINNING TO SETTLE INTO THE FAR NORTHERN KILX CWA. MEANWHILE
SOUTH OF THE BOUNDARY...A MOIST ENVIRONMENT CHARACTERIZED BY
DEWPOINTS IN THE 60S IS SUPPORTING SCATTERED SHOWERS/THUNDER
ACROSS THE REMAINDER OF THE AREA. COLD FRONT IS NOT EXPECTED TO
DROP MUCH FURTHER SOUTH TONIGHT...AS UPPER-LEVEL WAVE CURRENTLY
OVER EASTERN KANSAS WILL IMPEDE ITS SOUTHERN PROGRESS. AS A
RESULT...THINK FRONT WILL ONLY SINK TO JUST SOUTH OF THE I-72
CORRIDOR OVERNIGHT. AS A RESULT...WILL CONTINUE TO CARRY LOW
CHANCE POPS ACROSS THE CENTRAL ZONES...WITH HIGHEST POPS FOCUSED
ALONG/SOUTH OF I-70 WHERE DEEPEST MOISTURE AND STRONGEST LIFT WILL
BE PRESENT. WITH FRONT IN THE VICINITY AND DRIER AIRMASS ONLY
TRICKLING SLOWLY SOUTHWARD...THINK AREAS OF FOG WILL DEVELOP
OVERNIGHT. LAST NIGHT...FOG FORMED IN LOCATIONS NEAR/SOUTH OF THE
BOUNDARY WHERE DEWPOINTS HOVERED IN THE UPPER 50S/LOWER 60S. THOSE
CONDITIONS WILL LIKELY EXIST FURTHER SOUTH TONIGHT...PRIMARILY
ALONG/SOUTH OF I-70. NAM FORECAST SOUNDINGS PROVIDE A STRONG
SIGNAL FOR FOG AT BOTH KMTO AND KLWV AND HRRR VISBY PROGS SUPPORT
THIS AS WELL...SO HAVE INCLUDED AREAS OF FOG ACROSS THE SOUTHEAST
AFTER MIDNIGHT.
ANY FOG WILL GRADUALLY BURN OFF THURSDAY MORNING...HOWEVER SKIES
WILL REMAIN MOSTLY CLOUDY THROUGHOUT THE DAY ACROSS THE SOUTHEAST
AS THE FRONT MAKES ONLY VERY SLOW PROGRESS SOUTHWARD. WILL
CONTINUE WITH CHANCE POPS ALONG AND SOUTH OF A PARIS TO
SHELBYVILLE LINE...WITH DRY CONDITIONS EXPECTED FURTHER NORTH.
BOTH THE NAM AND GFS FINALLY GIVE THE BOUNDARY A GOOD PUSH
SOUTHWARD BY FRIDAY...AS HIGH PRESSURE BUILDS INTO THE UPPER
MIDWEST. WILL HOLD ON TO A SLIM CHANCE FOR A SHOWER SOUTH OF I-70
INTO FRIDAY IN CASE FRONT IS DELAYED...BUT WILL GO WITH MOSTLY
SUNNY AND DRY CONDITIONS ELSEWHERE.
WITH HIGH PRESSURE BEING THE DOMINANT WEATHER FEATURE...SUNNY
SKIES AND DRY WEATHER IS EXPECTED THIS WEEKEND. TEMPERATURES WILL
REMAIN NEAR NORMAL FOR THIS TIME OF YEAR...WITH DAYTIME HIGHS IN
THE LOWER TO MIDDLE 70S AND OVERNIGHT LOWS IN THE LOWER 50S.
LONG TERM...SUNDAY THROUGH WEDNESDAY
A VIGOROUS SHORT-WAVE WILL DIVE INTO THE GREAT LAKES LATE IN THE
WEEKEND...PUSHING A WEAK COLD FRONT/SURFACE TROUGH THROUGH CENTRAL
ILLINOIS SATURDAY NIGHT INTO SUNDAY. SYSTEM WILL HAVE VERY LITTLE
MOISTURE TO WORK WITH...SO AM ONLY EXPECTING A FEW CLOUDS AS IT
PASSES THROUGH. AFTER THAT...A MAJOR PATTERN CHANGE IS IN STORE
NEXT WEEK. BOTH THE GFS AND ECMWF ARE SHOWING AN UPPER-LEVEL RIDGE
BUILDING ACROSS THE PLAINS INTO THE MIDWEST BY THE MIDDLE AND END
OF THE WEEK. RISING HEIGHTS AND INCREASING SOUTHERLY FLOW WILL
BOOST TEMPS WELL INTO THE 70S BY MONDAY AND TUESDAY...THEN PERHAPS
INTO THE 80S AFTER THAT. BOTH MODELS INDICATE 850MB TEMPS IN THE
15 TO 17C RANGE BY NEXT WEDNESDAY...SUGGESTING A RETURN TO
SUMMER-LIKE WARMTH IN THE EXTENDED.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
503 AM EDT THU SEP 27 2012
.SHORT TERM...
TODAY THROUGH FRIDAY NIGHT.
PRIMARY CONCERN WRT OH VLY FRONTAL WAVE STRENGTH/POSITIONING AND
POTNL FOR SHRA TO SKIRT FAR SERN CWA LATER THIS AM. 27/00 UTC NAM
APPEARS TOO STRONG/NORTH WITH AFOREMENTIONED WAVE...AS SUCH WL
DISCOUNT/SUBJECTIVELY WEAKEN AND SHUNT SWD IN LIGHT OF MID
TROPOSPHERIC SPEED MAX ALONG OH RVR PER TCVG/KILN VWP AND CENTROID
OF SFC PRES FALLS ACRS ERN KY. INITIAL 5H ZONAL CONFLUENCY WITH
LOWER TROP FLOW WELL VEERED/STRENGTHENED SFC-4KFT PER KIND/KIWX VWP
DENOTING DRYING/SUBSIDENT AIRMASS ESTABLISHING FIRM FOOTHOLD
THROUGH ENTIRE SRN GRTLKS RGN AND INTO NRN EXTENT OF OH
VLY...BODING UNFAVORABLE FOR A SHARP NWD GENUFLECTION OF CURRENT
I70 CORRIDOR SHRA. 06 UTC NAM AND LATEST RAP RUNS APPEAR
MORE REASONABLE IN STRENGTH/POSITIONING...WL CONT WITH DRY
FORECAST TDY AND MONITOR TRENDS THROUGH AM HOURS...AS HIGH END
CHC/LOW LKLY 00 UTC GUID POPS CREATING APPREHENSION. BY DY2 DEEP
JAMES BAY/LWR GRTLKS TROFING DOMINATES WITH ARDENT NRN PLAINS
RIDGING LEADING TO DOWNSTREAM REXED CUT OFF...WITH CRISP/COOL/DRY
FALL AIRMASS. ONLY MINOR TWEAKS TO TEMPS/DPS REQRD.
&&
.LONG TERM...
SATURDAY THROUGH WEDNESDAY...THE FORECAST CHALLENGES EARLY INCLUDE
THE DEVELOPMENT OF A CUT OFF LOW DOWNSTREAM OF A TEMPORARY BLOCKING
RIDGE. PREFER THE RECENT PERFORMANCE OF THE ECMWF AND THE CURRENT
HANDLING OF ECMWF WITH THIS SYSTEM. KEPT THE FORECAST DRY AS
ISENTROPIC LEVELS INDICATE LIMITED MOISTURE AVAILABLE FOR THIS
SYSTEM. ALSO...THE BEST LIFT SHOULD REMAIN NORTHEAST OF THE FORECAST
AREA IN THE DEFORMATION ZONE. KEPT TEMPERATURES COOL SUNDAY...WITH
MODERATING TEMPERATURES THROUGH THE END OF THE PERIOD. LOWERED LOW
TEMPERATURES SUNDAY NIGHT GIVEN CLEARING SKIES...LIGHT WINDS...AND A
COOL AND DRY AIRMASS...IDEAL CONDITIONS FOR A SHALLOW RADIATION
INVERSION TO FORM.
&&
.AVIATION... /06 UTC TAFS/
PRIMARILY VFR THRU THE FCST PD AS DRY SUBSIDENT AIRMASS CONTINUES TO
DEEPEN ACRS NRN IN. NAM/RAP POINT SNDGS SUGGEST SIG DEGREE OF
RESIDUAL MOISTURE REMAINING WITHIN 950-900MB LYR AT KFWA WHICH MAY
PROVIDE CATALYST FOR MVFR CU FIELD AS SHALLOW CONVECTIVE OVERTURN
COMMENCES/DEEPENS WITHIN 1-2 HRS AFTER SUNRISE. EXPECT ANY MVFR CIGS
TO BE SHORTLIVED AND AOA FUEL ALT...BEFORE RISING ABOVE
3KFT/SPREADING OUT AT BASE OF SUBSIDENCE INVERSION...PER CONVECTIVE
CLOUD BASE/HGHT DIAGRAM.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK UNTIL 7 AM CDT THIS MORNING FOR INZ003.
MI...RIP CURRENT RISK UNTIL 8 AM EDT THIS MORNING FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ043-046.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1140 PM MDT WED SEP 26 2012
.UPDATE...
ISSUED AT 1121 PM MDT WED SEP 26 2012
LINE OF THUNDERSTORMS ASSOCIATED WITH THE MAIN UPPER LOW IS MOVING
ACROSS NORTHEAST COLORADO AND WILL OVERSPREAD THE WESTERN THIRD OF
THE FORECAST AREA OVERNIGHT...AND ALL BUT THE FAR EASTERN COUNTIES
THURSDAY MORNING. THE THREAT FOR SEVERE WEATHER APPEARS TO HAVE
DIMINISHED AS LATEST MESOANALYSIS FROM SPC SHOWS MUCAPE LESS THAN
500 J/KG AND MINIMAL DOWNDRAFT CAPE. OTHER QUESTION FOR THE
OVERNIGHT PERIOD WILL BE FOG. RUSSELL AND SALINA HAVE FOGGED IN AT
A QUARTER MILE IN THE LAST COUPLE OF HOURS. RUC SHOWS FOG/STRATUS
DEVELOPING IN THE EASTERN FORECAST AREA OVERNIGHT. DEW POINT
DEPRESSIONS ARE GRADUALLY LOWERING IN THE EAST...ALTHOUGH CLOUDINESS
AHEAD OF THE UPPER SYSTEM WILL INHIBIT RADIATIONAL COOLING. DECIDED
TO GO WITH PATCHY FOG FOR NOW UNTIL SEE SOME SIGNS OF FOG
DEVELOPING IN THE OBS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 200 PM MDT WED SEP 26 2012
THE UPPER LEVEL TROUGH NORTH OF THE FOUR CORNERS AREA WILL REMAIN
NEARLY STATIONARY THROUGH THE NIGHT. MEANWHILE THE AXIS OF
CONVERGENCE WILL SLOWLY PROGRESS NORTHEAST OUT OF THE AREA. AS THE
SUN SETS...AM ANTICIPATING ANY LINGERING STORMS ALONG THIS BAND TO
DISSIPATE. DURING THE OVERNIGHT HOURS AN UPPER LEVEL SHORT WAVE
TROUGH WITHIN THE SOUTHWEST FLOW MOVES OVER THE SOUTHWEST PART OVER
THE AREA. THE 700-500MB LAPSE RATES AHEAD OF THE TROUGH STEEPEN
WITH 150-300J/KG OF MU CAPE DEVELOPING IN THE LAYER. 0-6KM SHEAR
INCREASES FROM 20 TO 30KTS NEAR SUNRISE...HOWEVER AM NOT
ANTICIPATING ANY SEVERE THUNDERSTORMS ALTHOUGH A FEW MAY BECOME
STRONG WEST OF THE COLORADO BORDER PRODUCING SMALL HAIL OR GUSTY
WINDS. IN ADDITION ISENTROPIC LIFT DEVELOPS OVER THE WEST OF THE
COLORADO BORDER AHEAD OF THE TROUGH FURTHER AIDING IN LIFT. HAVE
PRECIP. CHANCES MOVING INTO THE AREA FOLLOWING THE TROUGH...WITH
CHANCES INCREASING AFTER MIDNIGHT TOWARD THE SOUTHWEST.
OVERNIGHT FOG MAY DEVELOP OVER THE MAJORITY OF THE AREA DUE TO DEW
POINTS REMAINING IN THE 50S. CURRENTLY AM ANTICIPATING VISIBILITIES
TO DROP TO A MILE IN THE DENSEST FOG. THE FOG SHOULD BURN OFF A
COUPLE HOURS AFTER SUNRISE.
THURSDAY THE UPPER LEVEL TROUGH NORTH OF THE FOUR CORNERS AREA
BEGINS TO PROGRESS EASTWARD. AS IT APPROACHES THE TRI-STATE AREA
SMALLER DISTURBANCES DEVELOP AHEAD OF THE MAIN TROUGH OVER THE
WESTERN PART OF THE AREA...WITH THE BEST CHANCES OCCURRING MID DAY.
POINT SOUNDINGS FROM ACROSS THE AREA INDICATE 500J/KG OF SURFACE
BASED CAPE TO WORK WITH...SO THUNDERSTORMS ARE NOT OUT OF THE
QUESTION. PRECIP. CHANCES WILL DECREASE DURING THE LATE AFTERNOON
AS LIFT FROM THE UPPER LEVEL TROUGH MOVES OUT OF THE AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 200 PM MDT WED SEP 26 2012
THURSDAY NIGHT-SUNDAY...STILL SOME DIFFERENCES IN THE HANDLING OF
THE WAVE THAT MOVES INTO THE AREA THURSDAY. THIS WAVE SHOULD MOVE
EAST THURSDAY NIGHT GIVEN THE NORTHWEST UPPER FLOW WITH THE
GFS/ECMWF THE FASTEST...THE NAM/GEM THE SLOWEST. EITHER
WAY...FRIDAY THROUGH MOST OF SATURDAY WILL BE DRY. MAY SEE SOME
THUNDERSTORMS VERY LATE IN THE DAY SATURDAY NEAR THE FLAGLER AREA
AS A DISTURBANCE MOVES IN FROM THE NORTHWEST. THIS DISTURBANCE
LOOKS TO CONTINUE MOVING GENERALLY ACROSS THE REMAINDER OF THE
AREA SATURDAY NIGHT AND SUNDAY WHERE SOME SLIGHT CHANCE POPS LOOK
WARRANTED. HIGH TEMPERATURES FRIDAY 65 TO 70 IN EASTERN COLORADO
WHERE CLOUDS AND PRECIPITATION MOST LIKELY...70-75 FURTHER EAST.
WITH LESS CLOUDINESS EXPECTED SATURDAY AND 850 TEMPERATURES
WARMING ABOUT 3-5F HIGHS IN THE MID TO UPPER 70S EXPECTED. ON
SUNDAY A BIT WARMER WITH MID 70S TO AROUND 80. OVERNIGHT LOWS A
BIT ABOVE NORMAL.
SUNDAY NIGHT-WEDNESDAY...PRETTY GOOD AGREEMENT THAT A LARGE RIDGE
OF HIGH PRESSURE SLOWLY MOVES TOWARD THE AREA THROUGH THE PERIOD.
PRECIPITATION IS NOT EXPECTED AND FOR THAT MATTER MUCH IN THE WAY
OF CLOUDINESS. A SLOW WARMING TREND WILL CONTINUE WITH MID 70S TO
LOW 80S MONDAY...LOW TO MID 80S BY WEDNESDAY. OVERNIGHT LOWS ABOVE
NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1121 PM MDT WED SEP 26 2012
AT KGLD...SHOWERS AND THUNDERSTORMS IN EASTERN COLORADO WILL MOVE
INTO NORTHWEST KANSAS OVERNIGHT AND CONTINUE THROUGH MUCH OF
THURSDAY. CEILINGS WILL BE LOWERING WITH THE ARRIVAL OF THE
PRECIPITATION BETWEEN 09-12Z AND SHOULD STAY IFR THROUGH MUCH OF
THURSDAY. OCCASIONAL LIGHTNING STRIKES/CB WILL BE POSSIBLE...BUT
STORMS ARE NOT EXPECTED TO BE SEVERE. BRIEF RESTRICTIONS IN
VISIBILITY WILL ALSO OCCUR NEAR ANY THUNDERSTORM.
AT KMCK..BIG QUESTION AS TO WHETHER FOG/STRATUS WILL DEVELOP OVERNIGHT
AND INTO THURSDAY MORNING. CURRENT OBSERVATIONS SUGGEST THERE MAY
BE SEVERAL HOURS OF REDUCED VISIBILITY AND LOWER CEILINGS...BUT
UNSURE HOW LOW TO GO SINCE NEAREST FOG IS CURRENTLY IN RUSSELL
KANSAS. MID/HIGH CLOUDS ARE PREVENTING FURTHER RADIATIONAL
COOLING...SO FOG WILL HAVE TO ADVECT FROM THE SOUTH WHICH IS SHOWN
BY SOME OF THE HIGHER RESOLUTION MODELS. FOR NOW...WILL HAVE A
TEMPO GROUP FOR FOG/STRATUS AROUND SUNRISE WHICH IS THE
CLIMATOLOGICALLY FAVORED TIME. PRECIPITATION WILL LIKELY HOLD OFF
IN KMCK UNTIL LATE THURSDAY AFTERNOON OR THURSDAY NIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...024
SHORT TERM...JTL
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS WICHITA KS
1155 PM CDT WED SEP 26 2012
.UPDATE...
REST OF THE NIGHT:
AREAS OF FOG...DENSE IN A SOME AREAS...DEVELOPED QUICKLY OVER CNTRL KS
LATE THIS EVENING WHERE SKIES HAD CLEARED. VBSYS DROPPED DRAMATICALLY
~1115PM. HAVE CHECKED SWING ON DENSE FOG ADVISORY ISSUANCE...FOR NOW.
AREAL EXTENT BEING WATCHED CLOSELY. TSRA THAT HAVE BEEN OCCURRING OVER
MOST OF OK THROUGHOUT THE EVENING APPEAR TO HAVE FORCED SFC FRONT S
TOWARD SRN OK...HOWEVER OUTFLOW MAKING LOCATION CHALLENGING. POSSESS
SUFFICIENT CONFIDENCE TO LOWER POPS CONSIDERABLY FOR ALL AREAS WITH
POPS REMOVED FROM CNTRL KS. POPS FOR REST OF CWA NOW RANGE FROM 40-50%
FOR OK-BORDERING COUNTIES TO ~20% ALONG HIGHWAY 400.
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THERE ARE NOW MAJOR CONCERNS FOR KSLN & KRSL WHERE +FG DEVELOPED AND
THICKENED RAPIDLY ~0415Z. THEREFORE PLACED BOTH TERMINALS IN VLIFR
STATUS FOR REST OF THE NIGHT. IT APPEARS...FOR NOW...THAT BOTH TAF
SITES WILL RAPIDLY RETURN TO VFR STATUS 14-15Z. HOWEVER! EXTENSIVE
MID-LVL CONVECTIVE DEBRIS IS SPREADING N & NE TOWARD CNTRL KS...SO
THIS WOULD DRAW CONSIDERABLE ATTENTION AS MORNING APPROACHES. TSRA
STILL ANTICIPATED FOR MUCH OF THE NEIGHBORHOOD ON THU BUT SCT NATURE
OF CONVECTION DICTATES ASSIGNING "VCTS" TO MOST TERMINALS FROM 15Z ONWARD.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT WED SEP 26 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
EARLY THIS EVENING A STATIONARY FRONT EXTENDED FROM THE TX PANHANDLE
JUST N OF KAMA DUE E ACROSS CNTRL OK TO NRN AR. ANTICIPATE THE FRONT
TO REMAIN SITUATED OVER THESE AREAS FOR MOST OF THE NIGHT & AS SUCH
BULK OF TONIGHT`S CONVECTION SHOULD LIKEWISE REMAIN OVER OK. IT IS
CONCEIVABLE THAT AS THE LOW-LVL JET DEVELOPS THE 925-MB FRONT MAY GET
FORCED ALMOST DUE N TOWARD THE OK/KS BORDER LATE TONIGHT. WITH SOME
INDICATION THAT THE FRONT MAY LIFT FURTHER N OVER SE KS HAVE LIMITED
"VCTS" MENTION TO KCNU EFFECTIVE 06Z WITH CONVECTION ELEVATED IN
NATURE. TSRA POTENTIAL CONTINUES FOR REMAINDER OF TAF PERIOD WITH
GREATEST EXISTING ACROSS SC & SE KS ON THU WHERE NO DOUBT CLOSER TO
THE AFORE-MENTIONED FRONT.
PREV DISCUSSION... /ISSUED 229 PM CDT WED SEP 26 2012/
DISCUSSION...
SYNOPSIS...THE MCV LEFT FROM LAST NIGHTS CONVECTION WAS CENTERED
ABOUT 55 MILES NORTHWEST OF SALINA. CONVECTION FROM THIS IS
FESTERING NEAR AND EAST OF THE CENTER...EXTENDING INTO MISSOURI.
A STRONG RESIDENT COLD POOL REMAINED IN PLACE ACROSS THE FORECAST
AREA FOR MUCH OF THE MORNING...MAKING RECOVERY OF THE ATMOSPHERE
QUITE SLOW. OF NOTE AS WELL IN THE VISIBLE IMAGERY ARE GRAVITY
WAVES PROPAGATING AWAY FROM THE CONVECTION TO THE SOUTH AND
SOUTHWEST...THE MOST RECENT OF WHICH HAS INCREASING CONVERGENCE
ALONG IT.
THE COLD POOL HAS PUSHED THE COLD FRONT ALL THE WAY INTO OKLAHOMA
AND ARKANSAS...WITH AN 18Z POSITION EXTENDING FROM A
KRUE-KFSM-KOKC-KDDC APPROXIMATION.
FROM 18Z TO 19Z...TEMPERATURES HAVE RISEN INTO THE MID 70S ACROSS
SOUTH-CENTRAL KANSAS WHERE THE COLD POOL HAS NEARLY MIXED OUT. SOME
CUMULUS HAVE STARTED TO FORM IN THIS AREA AS A RESULT.
UPPER LEVEL ANALYSIS ENDING AT 19Z SHOWS AN UPPER LOW CENTERED OVER
THE FOUR CORNERS REGION...WITH IMPULSES OF ENERGY ROTATING AROUND
IT. THESE ARE THE MAIN IMPULSES AFFECTING THE AREA.
ANOTHER DISTURBANCE WAS NOTED IN THE WATER VAPOR IMAGERY MOVING
ALONG THE U.S. CANADIAN BORDER OF CENTRAL MONTANA. A VERY DEEP AREA
OF LOW PRESSURE WAS OVER THE GULF OF ALASKA WITH WEAKENING LOW
PRESSURE OVER NORTHERN QUEBEC.
THE MAIN FORECAST FOCUS WILL BE ON CONVECTION OVER THE NEXT SEVERAL
DAYS.
TONIGHT - THE MAIN FORCING MECHANISM FOR CONVECTION SHOULD ONCE
AGAIN BE LOW LEVEL MOISTURE TRANSPORT INTERSECTING THE FRONT. THE
MOISTURE TRANSPORT VECTORS...ISENTROPIC LIFT AT 305K AND 310K...AND
THE 1000MB-850MB FRONTOGENESIS REALLY ISOLATE WHERE THIS SHOULD
OCCUR. THE BULK OF THE NWP CONTINUE TO FAVOR AN AREA OVER SOUTHEAST
KANSAS. THIS IS EXPECTED TO OCCUR LATE THIS EVENING.
A SECOND AREA SHOULD CONTINUE IN THE VICINITY OF THE MCV...WHERE
CONVECTION FESTERS THIS AFTERNOON. A THIRD AND FINAL AREA OF
CONVECTION WILL MOVE INTO THE AREA FROM THE WEST. THE NAM-WRF
AND THE HRRR BOTH SHOW STORMS MOVING OFF THE HIGH PLAINS INTO THE
WESTERN PART OF THE STATE. THESE REACH THE FORECAST AREA AT VARIOUS
TIMES. THE HRRR /MULTIPLE RUNS FROM 10Z THROUGH 15Z/ BRING THIS
CONVECTION INTO WESTERN KANSAS BY 01Z...THE 26.12Z NAM-WRF BRINGS IT
INTO WESTERN KANSAS BETWEEN 06Z AND 09Z.
THIS HAS A GREAT AFFECT ON THE FORECAST AND WHETHER WE GET
ADDITIONAL CONVECTION ALONG THE SOUTHERN PERIPHERY OF THE FORECAST
AREA. HAVE LOW CONFIDENCE IN TIMING OF THIS SYSTEM. THE LATEST RAP
AT 18Z SHOWS A STRONG LOW LEVEL JET ACROSS THE HIGH PLAINS...WHICH
WOULD FAVOR THE NAM-WRF. STILL...CONFIDENCE IS RATHER LOW.
THURSDAY - ANY ONGOING CONVECTION IN THE MORNING SHOULD GRADUALLY
DIMINISH DURING THE MORNING. DURING THE AFTERNOON...THERE SHOULD BE
ENOUGH RESIDUAL MOISTURE IN THE BOUNDARY LAYER TO ENABLE SOME
ADDITIONAL SHOWERS AND THUNDERSTORMS...THOUGH NOTHING LOOKS
ORGANIZED AT THIS TIME.
FRIDAY THROUGH WEDNESDAY - HIGH PRESSURE MOVES INTO THE
REGION...BOTH THE 26.12Z ECMWF AND THE 26.12Z GFS AGREE ON THAT.
THEY ALSO HAVE A COLD FRONT...ASSOCIATED WITH A LOW IN THE NORTHERN
STREAM UP IN CANADA...MOVING THROUGH THE REGION ON SUNDAY. THIS
FRONT SHOULD BE DRY SINCE THE GULF IS CLOSED OFF.
ON WEDNESDAY...ANOTHER COLD FRONT MOVES SOUTH THEN STALLS OVER THE
REGION. PRECIPITATION CHANCES WITH THIS FRONT SHOULD BE A BIT
BETTER.
LOOKING OUT AHEAD...A SIGNIFICANT PATTERN CHANGE MAY BE UNDERWAY. A
VERY DEEP TROUGH IS FORECAST TO DEVELOP OVER THE WESTERN U.S. THIS
PRODUCES A STRONG DEEP SURFACE LOW OVER THE NATIONS
MID-SECTION...WITH STRONG HIGH PRESSURE OVER THE NORTHWESTERN U.S.
AND CANADA IN THE LEE OF THE ROCKIES. THIS COULD BE THE FIRST
SIGNIFICANT SNOW STORM OF THE SEASON FOR THE NORTHERN PLAINS AND
SOUTHERN CANADA.
COOK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 62 76 61 74 / 40 50 60 50
HUTCHINSON 60 75 60 74 / 30 40 50 40
NEWTON 60 75 60 73 / 30 40 50 40
ELDORADO 61 76 60 73 / 40 40 50 50
WINFIELD-KWLD 64 78 63 75 / 40 50 60 50
RUSSELL 54 74 56 74 / 20 30 40 30
GREAT BEND 57 74 58 74 / 20 40 50 40
SALINA 56 76 57 76 / 70 20 30 30
MCPHERSON 59 75 58 74 / 30 40 40 40
COFFEYVILLE 65 79 63 75 / 80 50 70 60
CHANUTE 63 76 61 74 / 60 50 50 40
IOLA 62 76 60 74 / 50 40 40 40
PARSONS-KPPF 64 78 62 75 / 70 50 60 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
136 AM EDT THU SEP 27 2012
.UPDATE...
ISSUED AT 130 AM EDT THU SEP 27 2012
THE LATEST TRENDS IN SATELLITE AND RADAR IMAGERY INDICATE A DISTINCT
AND STEADY WEAKENING TREND IN A LINE OF SHOWERS AND STORMS THAT
STRETCHES ALONG AND JUST SOUTH OF THE OHIO RIVER FROM CENTRAL
KENTUCKY AND ACROSS SOUTHERN OHIO. A FEW SHOWERS AND STORMS HAVE
MANAGED TO HOLD TOGETHER LONG ENOUGH TO MOVE ACROSS FLEMING AND BATH
COUNTIES...BUT THE BULK OF THE EXISTING STORMS ARE PUSHING
NORTHEASTWARD INTO INDIANA AND OHIO. MOST OF THE SHOWERS AND STORMS
THAT HAD BEEN MOVING ACROSS CENTRAL KENTUCKY THAT PAST SEVERAL HOURS
HAVE DISSIPATED EVERYWHERE EXCEPT ALONG THE RIVER. THAT BEING
SAID...AND WITH THAT LATEST MODEL DATA ALSO SUPPORTING IT...HAVE
REMOVED MENTION OF PRECIPITATION FROM THE FORECAST FOR THE REST OF
THE NIGHT EVERYWHERE EXCEPT POINTS ALONG AND NORTH OF THE I64
CORRIDOR. IT LOOKS THERE WILL BE A LULL IN THE ACTIVITY UNTIL JUST
AFTER SUNRISE TODAY...AT WHICH TIME A LOW LEVEL DISTURBANCE AND
FRONTAL BOUNDARY BEGIN MAKING THEIR WAY SOUTHWARD TOWARD CENTRAL AND
EASTERN KENTUCKY. MOST ACTIVITY WILL LIKELY REMAIN CONFINED TO AREAS
NORTH OF THE HAL ROGERS PARKWAY UNTIL AROUND 17Z TODAY. THE FORECAST
GRIDS HAVE BEEN MODIFIED TO REFLECT THE AFOREMENTIONED TRENDS IN THE
MODEL DATA AND REAL TIME OBSERVATIONS. THE UPDATED ZONE FORECAST
TEXT PRODUCT WILL BE ISSUED SHORTLY.
UPDATE ISSUED AT 1040 PM EDT WED SEP 26 2012
RADAR REMAINS QUITE ACTIVE AS OF 10 PM WITH A STRUNG OUT LINE OF
CONVECTION ALONG THE OHIO RIVER SLOWLY DRIFTING EAST-NORTHEAST ON
TRACK TO CLIP OUR BLUEGRASS COUNTIES FROM ABOUT 11 PM THROUGH AROUND
3 AM. OF GREATER CONCERN IS THE LINE OF CONVECTION PUSHING INTO
CENTRAL KY...MOVING EAST AT AROUND 30-35 MPH. WARMING CLOUD TOPS AND
LOWERING ENHANCED ECHO TOPS ALONG WITH DIMINISHING LIGHTNING ACTIVITY
ALL SUGGEST AN OVERALL WEAKENING TREND...HOWEVER A WELL DEFINED
OUTFLOW EVIDENT ON THE LMK 0.5 DEG SLICE IS CURRENTLY PUSHING SOUTH
ACROSS CENTRAL KY...SET TO INTERCEPT THE INBOUND LINE OF TSTMS FROM
THE WEST. THIS LINE APPEARS TO HAVE A GOOD COLD POOL TO WORK WITH AND
WITH ADDITIONAL LIFT FROM THE INTERACTION WITH THE OUTFLOW...AM
EXPECTING AN UPTICK IN ACTIVITY AS THIS LINE APPROACHES THE LAKE
CUMBERLAND REGION.
NEAR TERM MODELS CONTINUE TO SHOW ACTIVITY WANING OVER ALL BUT NRN
CENTRAL KY BEFORE IT REACHES OUR AREA...BUT HAVE BUCKED THE GUIDANCE
AND INCREASED POPS TO LIKELY OVER A GOOD PORTION OF OUR SWRN ZONES
FOR THE REMAINDER OF THE OVERNIGHT PERIOD WITH THE EXPECTATION THAT
THE LINE OVER CENTRAL KY WILL SURVIVE THE TRANSIT INTO THE CWA. GUSTY
WINDS CONTINUE TO APPEAR TO BE THE MAIN THREAT...THOUGH EVEN THE
STRONGEST STORMS HAVE ONLY BEEN PRODUCING GUSTS AROUND 35 TO 40
MPH...AND DO NOT FORESEE ANYTHING STRONGER DEVELOPING OVERNIGHT.
UPDATED GRIDS...ZONES...AND HWO HAVE BEEN SENT.
UPDATE ISSUED AT 650 PM EDT WED SEP 26 2012
SCATTERED CONVECTION CONTINUES TO DRIFT ACROSS OUR BLUEGRASS COUNTIES
THIS EVENING WITH RAINFALL THUS FAR LESS THAN 1/4 INCH. THE NEAR TERM
GUIDANCE GENERALLY APPEARS TO HAVE A GOOD HANDLE ON THE SCATTERED
CONVECTION UPSTREAM OVER WRN KY...DEPICTING THIS ACTIVITY TO
DISSIPATE OVER THE NEXT FEW HOURS BEFORE REACHING THE CWA...WITH
RESIDUAL ACTIVITY OVERNIGHT REMAINING BELOW SEVERE LIMITS AND
PREDOMINANTLY AFFECTING AREAS OVER NERN KY. THE CURRENT FORECAST HAS
ALL OF THIS WELL IN HAND...AND GENERALLY ONLY NEEDED MINOR MASSAGING
TO THE TEMP AND DEW PT CURVES HEADING INTO THE OVERNIGHT PERIOD.
METMOS APPEARS TO HAVE A FAIRLY GOOD HANDLE ON THE TEMP/DEW PT REGIME
ATTM...AND IS HINTING AT SOME TYPICAL ERN KY PATCHY VALLEY FOG
TOWARDS DAWN...SO WILL ADD THIS TO THE MIX FOR AREAS GENERALLY ALONG
AND SOUTH OF THE HAL ROGERS/KY 80 CORRIDOR WHERE CLEARER SKIES ARE
EXPECTED TO PREVAIL OVERNIGHT. UPDATED GRIDS HAVE BEEN SENT...AND
FRESH ZONES WILL BE ISSUED SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 309 PM EDT WED SEP 26 2012
QUASI STATIONARY FRONTAL BOUNDARY REMAINS FROM LAKE ONTARIO TO
NORTHERN ILLINOIS...WHILE ANOTHER WEAK BOUNDARY IS ACROSS NORTHERN
KY. A SERIES OF CONVECTIVE COMPLEXES HAS BEEN MOVING ENE THROUGH THE
OH VALLEY...AND THIS SCENARIO LOOKS TO CONTINUE THROUGH THE FORECAST
PERIOD...WITH A GRADUAL SHIFT SOUTH OF THE ACTIVITY AS THE PRIMARY FRONT
SAGS SOUTH. MODEL CONSENSUS IS THAT THE FOCUS OF THE REPEATED RAINS
WILL BE NORTHWEST OF THE FORECAST AREA...AND THUS HEAVIEST RAIN
TOTALS ARE EXPECTED TO REMAIN OUTSIDE OF FORECAST AREA. HPC HAS
PLACED THE EXTREME WESTERN EDGE OF THE FORECAST AREA IN A SLIGHT RISK
FOR EXCESSIVE RAINS. PRECIPITABLE WATER IS FORECAST TO BE IN EXCESS
OF THE 75TH PERCENTILE...BUT NOT TO BECOME TOO EXCESSIVE WITH PW
GETTING UP NEAR 1.5 INCHES. NONE THE LESS IF THE THE REPEATED RAINS
SET UP FURTHER SOUTH THE SITUATION WILL NEED TO BE MONITORED
CLOSELY. HOWEVER FLOOD THREAT FOR OUR AREA LOOKS MINIMAL AT THIS TIME.
CONVECTION CURRENTLY OVER SOUTHEASTERN INDIANA SHOULD REMAIN NORTH
OF THE FORECAST AREA LATE THIS AFTERNOON AND EVENING...BUT MAY
AFFECT THE FAR NORTHERN PART OF THE FORECAST AREA IF DEVELOPMENT
OCCURS FURTHER TO THE SOUTH. CONVECTION NOW OVER SOUTHEASTERN MO IS
MORE LIKELY TO AFFECT THE FORECAST AREA TONIGHT...AND THIS IS PICKED
UP ON BY THE HRRR.
LOW LEVEL JET LOOKS TO INCREASE EARLY TONIGHT...SO THIS SHOULD HELP TO
INCREASE THE PRECIPITATION CHANCES...MAINLY IN THE NORTH. THE
NORTHERN PART OF THE FORECAST AREA ALSO REMAINS IN A SLIGHT RISK FOR
SEVERE THUNDERSTORMS PER THE LATEST SPC DAY 1 OUTLOOK. HOWEVER SINCE
CONVECTION DID NOT DEVELOP THIS AFTERNOON ALONG THE OLD BOUNDARY
CURRENTLY OVER THE AREA IT APPEARS THE THREAT FOR SEVERE WEATHER WILL
BE DECREASING. IT APPEARS WE WILL NEED TO WAIT FOR THE COMPLEX
CURRENTLY DEVELOPING OVER MO TO MOVE ACROSS THE AREA TONIGHT. HOWEVER
BASED ON LATEST HRRR SHORT RANGE GUIDANCE THIS CONVECTION SHOULD
WEAKEN AS IT MOVES INTO OUR AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 309 PM EDT WED SEP 26 2012
MODELS ARE IN FAIR AGREEMENT TO START THE EXTENDED FCST. A SLOWLY
SAGGING TROF EXTENDS FROM WEST TO EAST ACROSS THE COMMONWEALTH. PCPN
IN THE FORM OF WAVES TRACKS ALONG THE FRONTAL ZONE WITH DIFFERENCES
IN THE DETAILS. HIGH PRESSURE FORCES THE FRONTAL ZONE SOUTH OF THE
STATE WITH THE GFS SLIGHTLY QUICKER IN CLEARING OUT THE PCPN. HAVE
CHOSEN TO FOLLOW THIS TREND AS THE HIGH PRESSURE OVER THE NORTHERN
PLAINS INITIALIZES BETTER IN THIS RUN. THIS PLACES CHANCE POPS
ACROSS THE ENTIRE CWA WITH 30S IN THE NORTH AND 50S SOUTH ON FRI.
FRI NIGHT AND SAT SHOWS CLEARING IN THE NORTH WITH CHANCE POPS IN THE
SOUTH FOLLOWED ON SAT NIGHT WITH NO POPS FOR THE ENTIRE AREA. THE DRY
WEATHER THEN CONTINUES THRU THE REMAINDER OF THE FCST AS HIGH
PRESSURE SETTLES OVER THE CNTRL APPALACHIANS AND THE MID ATLANTIC
COAST. THIS HIGH EXTENDS WEST INTO THE CNTRL PLAINS AND CUTS OFF ANY
RETURN FLOW FROM THE GULF. HENCE THE DEWPOINTS WILL DROP AS THE
DRIER AIR SETTLES IN WITH THE PLAINS HIGH WITH VALUES IN THE UPPER
40S AND LOWER 50S. TEMPERATURES WILL START IN THE MID 70S ON FRI BUT
DROP TO THE UPPER 60S WITH THE CLOUDS AND RAIN ON SAT. THEN AS THE
FRONT EASES SOUTH LOOK FOR HIGH TEMPS TO RECOVER INTO THE LOWER 70S
ON SUN AND CONTINUE CLIMBING SLOWLY TO THE MID 70S AGAIN BY WED.
LOWS WILL REMAIN FAIRLY STEADY IN THE 50S WITH MONDAY MORNING THE
COOLEST AS THE MERCURY SHOULD FALL TO AROUND 50.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 135 AM EDT THU SEP 27 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE TAF SITES UNTIL AROUND
10Z. FROM 10-12Z THIS MORNING...SKIES WILL LIKELY BE CLEAR ENOUGH FOR
SOME FOG TO FORM AT AND NEAR LOZ AND SME. SHOWERS AND STORMS THAT HAD
BEEN QUITE NUMEROUS ACROSS CENTRAL KENTUCKY DURING THE LATE EVENING
HOURS...HAVE SINCE DECREASED GREATLY IN SPATIAL COVERAGE AND
INTENSITY. IN FACT...MOST REMAINING SHOWERS AND STORMS ARE CONFINED
TO AN AREA ALONG THE OHIO RIVER. IT APPEARS THAT THE TAF SITES WILL
BE SPARED FROM SHOWER AND STORM ACTIVITY UNTIL 15Z OR SO TODAY. THE
BEST CHANCE FOR SHOWERS AND STORMS AT THE TERMINALS WILL BE FROM 17Z
ONWARD TODAY...AS THE SFC BOUNDARY IS EXPECTED TO BECOME ACTIVE
AGAIN...BRINGING A RENEWED...MORE WIDESPREAD THREAT OF SHOWERS AND
STORMS TO THE AREA. SOUTHERLY WINDS WILL REMAIN LIGHT OVERNIGHT
BEFORE REENGAGING AFTER 15Z...VEERING TO THE WEST AT AROUND 5 TO 10
KTS THROUGH THE AFTERNOON AND EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...SBH
LONG TERM....DUSTY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
436 AM EDT THU SEP 27 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE TRAVELING ALONG A SLOW MOVING FRONTAL
BOUNDARY WILL BRING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS
TODAY. THE BOUNDARY WILL MOVE SOUTH OF THE OHIO RIVER TONIGHT
FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR FRIDAY. LOW PRESSURE
IN THE UPPER ATMOSPHERE WILL PROVIDE CLOUDS AND POSSIBLY A FEW
SHOWERS OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT IS SAGGING SLOWLY SOUTH THROUGH OHIO. A WAVE OF LOW
PRESSURE TRAVELING ALONG THE FRONT IS DEPICTED RATHER WELL ON THE
NAM AND RAP MODELS WHICH SHOW THE WAVE CROSSING THE ILN AREA
TODAY. THIS WILL BRING WIDESPREAD SHOWERS AND ISOLATED
THUNDERSTORMS FOR MOST OF THE FORECAST AREA...AND CURRENT RADAR
TRENDS SUPPORT THIS SCENARIO. WENT WITH CATEGORICAL POPS FOR MUCH
OF THE AREA...DECREASING TO CHANCE FROM WEST TO EAST DURING THE
AFTERNOON.
THE LACK OF INSTABILITY SHOULD KEEP ANY THUNDERSTORMS THAT FORM
BELOW SEVERE LIMITS. TEMPERATURES SHOULD TOP OUT AROUND 70 THIS
AFTERNOON...THOUGH THERE IS A GREAT DEAL OF UNCERTAINTY WITH
RESPECT TO TEMPERATURES DUE TO CLOUDS...PRECIPITATION...AND
FRONTAL POSITION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
MODELS NOW SHOW THE FRONT DROPPING FARTHER SOUTH THAN WAS
PREVIOUSLY INDICATED. THEREFORE...WENT WITH A DRY FORECAST FROM LATE
TONIGHT THROUGH FRIDAY NIGHT AS HIGH PRESSURE AND DRIER AIR WORK
IN FROM THE NORTH.
A DEEP CUT OFF UPPER LOW WILL BE MOVING SOUTH FROM CANADA TOWARD
THE ILN AREA ON SATURDAY. MOISTURE ASSOCIATED WITH THE SYSTEM SHOULD
STAY MAINLY TO THE NORTH...BUT CLOUDS WILL PROBABLY INCREASE AND
ISOLATED SHOWERS MAY AFFECT NORTHERN COUNTIES SATURDAY AFTERNOON.
HIGH TEMPERATURES ARE EXPECTED TO BE AROUND 70 BOTH FRIDAY AND
SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. FOR SUNDAY...FOCUSED
ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU. TIMING
OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT AND
ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR BOTH
SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON
TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD.
SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL
DAYTIME HIGHS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
IN SPLIT FLOW PATTERN S/W OVER THE MID MS VLY TO RIPPLE EAST THRU
THE OHIO VALLEY THIS MORNING. NUMERICAL MODEL SOLNS IN BETTER
AGREEMENT WITH ASSOCIATED SFC LOW TO TRACK E INTO SW OHIO ALONG A
SLOW MOVING E-W ORIENTED SFC FRONTAL BOUNDARY. AREA OF SHOWERS AND
THUNDERSTORMS TO EXPAND NORTH ACRS THE TAF SITES THIS MORNING IN A
REGION OF FAVORABLE 925 MB CONVERGENCE. WILL ALLOW FOR A PERIOD OF
SHOWERS AND THUNDERSTORMS THIS MORNING WITH CIGS DROPPING INTO
MVFR CATEGORY. WITH THE PASSAGE OF THIS SFC WAVE THE FRONTAL
BOUNDARY WILL SINK SLOWLY SOUTH OF THE TAF SITES BY LATE AFTN.
EXPECT TO SEE CIGS IMPROVE THIS EVENING TO VFR BUT SOME BR
DEVELOPMENT WILL BE POSSIBLE. HAVE LIMITED RESTRICTION TO MVFR
AT THIS TIME.
.OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...PADGETT
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
131 AM EDT THU SEP 27 2012
.SYNOPSIS...
A SLOW MOVING FRONTAL BOUNDARY WILL GRADUALLY MOVE THROUGH THE
OHIO VALLEY THIS WEEK. SOUTH OF THE FRONT...SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO IMPACT THE REGION. HIGH PRESSURE
WILL BUILD IN ON SATURDAY...BUT AN UPPER LEVEL LOW PRESSURE
CENTER WILL PROVIDE A CHANCE OF SHOWERS ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
TRIED TO REMOVE SHOWERS IN THE I-70 CORRIDOR WEST OF COLUMBUS AND
NOTED THAT PATCHY DENSE FOG IS BEING REPORTED WHERE SKY COVER
ALLOWS RADIATIONAL COOLING TO LOWER TEMPS TO THE ALREADY MOIST
LOWER LAYER OF THE ATMOSPHERE. DO NOT EXPECT THE FOG TO REMAIN FOR
THE ENTIRE OVERNIGHT AS UPSTREAM CLOUD COVER WILL HAMPER THE DROP
IN TEMPERATURES AND VSBYS SHOULD WAFFLE FOR A COUPLE OF HOURS
THROUGH DAYBREAK. ANY CHANCES OF SHOWERS NORTH OF THE METRO CINCY
AREA SHOULD NOT SEE A CHANCE OF THUNDER FOR THE REMAINDER OF THE
NIGHT...I DID NOT ADJUST FORECAST BEYOND DAYBREAK BUT EXPECT THAT
THE ELEVATED INSTABILITY WILL BE LIMITED IN THIS AREA TOMORROW AS
WELL. PREVIOUS DISCUSSION BELOW.
SOUTH OF A SLOWLY-MOVING COLD FRONT...THE CWA REMAINS ENTRENCHED
IN AN AREA OF DEEP MOISTURE AND MODERATE WEST-SOUTHWESTERLY FLOW
IN THE LOWER TO MID LEVELS. THE PRIMARY FORECAST FOCUS IS ON
CONVECTIVE CHANCES AND TIMING TONIGHT.
CONVECTION ONGOING ACROSS THE CWA APPEARS TO BE ASSOCIATED WITH A
WEAK VORTICITY CENTER OVER INDIANA...WITH THE NEW DEVELOPMENT
FIRING UP ON A BAND WELL OUT AHEAD OF IT. MEANWHILE...THE WSW-ENE
ORIENTED BAND OF SHOWERS (WITH EMBEDDED THUNDER) THROUGH CENTRAL
OHIO IS JUST AHEAD OF THE BOUNDARY. INSTABILITY HAS BUILT TO ABOUT 1000
J/KG IN NORTHERN KENTUCKY...AND IS GREATER FURTHER TO THE
SOUTHWEST. RUC13 INSTABILITY FORECASTS OF 2000-2500 J/KG ARE MUCH
TOO HIGH...GIVEN THE ERRONEOUS ADVECTION OF DEWPOINTS OVER 70
DEGREES INTO SW OHIO.
POPS ARE CATEGORICAL FOR THE FIRST FEW HOURS OF THE FORECAST...AS
THE CURRENT ACTIVITY WORKS ITS WAY THROUGH THE CWA. AFTER
THAT...MUCH OF THE CWA MAY SEE A BREAK FROM CONVECTIVE
POTENTIAL...IN THE WAKE OF THE AFTERNOON SYSTEM. WHERE INSTABILITY
IS GREATER IN THE SOUTH...ADDITIONAL DEVELOPMENT IS POSSIBLE.
GIVEN THE 40 KNOTS OF 0-3 KM SHEAR (WHICH IS ACTUALLY STRONGER
THAN THE 0-6 KM SHEAR)...SOME STORM ORGANIZATION AND A FEW STRONG
CELLS WILL BE POSSIBLE. WITHOUT A KEY TRIGGER OR MUCH
INSTABILITY...WIDESPREAD SEVERE WEATHER DOES NOT APPEAR POSSIBLE.
POPS WILL BE KEPT IN THE LIKELY CATEGORY FOR THE SOUTHEASTERN TWO
THIRDS OF THE CWA GOING INTO TONIGHT. HOWEVER...GIVEN THE LACK OF
PRECIPITATION BEHIND THE CURRENT INDIANA/OHIO SYSTEM...IT APPEARS
THAT THE ACTIVITY WILL BE SHOWERY AND NOT ALL OF IT WILL BE
CONVECTIVE. DEVELOPING STORMS IN SOUTHERN ILLINOIS MAY BE WHAT
ENDS UP PROVIDING A GREATER CHANCE OF PRECIPITATION LATER ON
TONIGHT.
THE HOLES IN THE CLOUD COVER ALLOWED THE SOUTHERN CWA TO APPROACH
80 DEGREES TODAY. GIVEN THE WARMER STARTING POINT...AND EXPECTED
MOIST AND CLOUDY ATMOSPHERE TONIGHT...MIN TEMPS IN THE SOUTH WERE
BUMPED UP A FEW DEGREES FROM THE PREVIOUS FORECAST. WITH THE FRONT
MOVING INTO THE AREA...AND COLD ADVECTION BEGINNING IN THE
NORTH...THE TEMPERATURE GRADIENT OVERNIGHT WILL BE SOMEWHAT TIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL CONTINUE TO MAKE VERY SLOW PROGRESS TO
THE EAST ON THURSDAY...BUT ENOUGH PROGRESS TO BRING AN END TO ANY
SIGNIFICANT CHANCES OF PRECIPITATION. THE FRONT WILL ORIENT ITSELF
EAST-TO-WEST ACROSS KENTUCKY...AND STALL OUT THROUGH FRIDAY. THIS
MEANS THAT THE MOISTURE AND FORCING ASSOCIATED WITH THE FRONT WILL
BE VERY CLOSE TO THE SOUTHERN EDGE OF THE FORECAST AREA. THIS
WILL REQUIRE A CHANCE OF SHOWERS (WITH A POSSIBILITY OF
THUNDERSTORMS) IN THE SOUTHERN HALF OF THE CWA FOR THURSDAY...AND
THEN JUST THE SOUTHERN THIRD OF THE CWA ON FRIDAY. AS THE VARIOUS
MODELS (AND THEIR VARIOUS RUNS) CONTINUE TO STRUGGLE WITH TIMING
THE EMBEDDED DISTURBANCES IN THE QUICK LOWER-TO-MID-LEVEL
FLOW...IT REMAINS DIFFICULT TO PIN DOWN THE TIME OR PLACEMENT OF
ANY NORTHWARD-IMPINGING CONVECTIVE SYSTEMS THAT MAY IMPACT THE CWA
DURING THIS TIME FRAME.
MAX TEMPERATURES WERE ADJUSTED SLIGHTLY DOWN THROUGH THE END OF
THE WEEK...AS THE COLD ADVECTION BEHIND THE FRONT WILL KEEP TEMPS
FROM REACHING 70. THE TEMPERATURE GRADIENT WILL BE TIGHTER ON
THURSDAY...WITH THE FRONT STILL IN THE AREA. GUIDANCE AND MODEL
NUMBERS EXHIBITED LITTLE SPREAD...INCREASING CONFIDENCE IN THE
FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. SAT AND SUN
FOCUSED ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU.
TIMING OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT
AND ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR
BOTH SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON
TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD.
SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL
DAYTIME HIGHS.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
IN SPLIT FLOW PATTERN S/W OVER THE MID MS VLY TO RIPPLE EAST THRU
THE OHIO VALLEY THIS MORNING. NUMERICAL MODEL SOLNS IN BETTER
AGREEMENT WITH ASSOCIATED SFC LOW TO TRACK E INTO SW OHIO ALONG A
SLOW MOVING E-W ORIENTED SFC FRONTAL BOUNDARY. AREA OF SHOWERS AND
THUNDERSTORMS TO EXPAND NORTH ACRS THE TAF SITES THIS MORNING IN A
REGION OF FAVORABLE 925 MB CONVERGENCE. WILL ALLOW FOR A PERIOD OF
SHOWERS AND THUNDERSTORMS THIS MORNING WITH CIGS DROPPING INTO
MVFR CATEGORY. WITH THE PASSAGE OF THIS SFC WAVE THE FRONTAL
BOUNDARY WILL SINK SLOWLY SOUTH OF THE TAF SITES BY LATE AFTN.
EXPECT TO SEE CIGS IMPROVE THIS EVENING TO VFR BUT SOME BR
DEVELOPMENT WILL BE POSSIBLE. HAVE LIMITED RESTRICTION TO MVFR
AT THIS TIME.
.OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...FRANKS/HATZOS
SHORT TERM...HATZOS
LONG TERM...PADGETT
AVIATION...AR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
342 AM EDT THU SEP 27 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT OVER NORTHWEST PENNSYLVANIA EARLY THIS
MORNING WILL DRIFT SOUTH ACROSS THE STATE OVERNIGHT AND BECOME
LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER LATER TODAY WHERE
IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS
FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE
SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A
DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN
CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST
STATES THIS WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE
THROUGH KGKJ NEWD THROUGH WARREN AND KELZ THIS HOUR. TO THE SOUTH...
SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION
BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB
JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND
MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST
CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL
AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER
MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG
AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING
SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF
THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND
NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT.
LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT
COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS.
THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF
INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST
SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING
STATIONARY THERE THROUGH THURSDAY NIGHT.
A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3
TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS
OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS
POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS
THE NRN MTNS.
SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE
OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER
50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS
GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 AM FRIDAY/...
FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL
PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH.
THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE
MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR
MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND
IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER
LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S.
MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF
THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW
DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED
STATES WILL LIFT OUT ON FRIDAY IN FAVOR OF A STRONGER UPPER TROF
DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND CUTTING OFF OVER THE
CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY AND SUNDAY. THIS
WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE REGION ON
FRIDAY AND FRIDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS
RETURN FOR LATER SATURDAY AND ESPECIALLY SUNDAY OVER CENTRAL PA.
THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE
THIS WEEK AND THIS WEEKEND. BOTH THE GFS AND EC SHIFT FOCUS OF
HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE UPPER LOW
IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT LAKES.
WHILE UNSETTLED CONDITIONS WILL PERSIST THROUGH THE WEEKEND AND
INTO MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE
EAST COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL
APPEARS LOW...AS THE OFFSHORE RICH MOISTURE PLUME FEEDING
NORTHWARD TO EASTERN NEW ENGLAND DOES NOT EFFECTIVELY PHASE WITH
THE DEVELOPING GREAT LAKES CUTOFF. AS A RESULT...QPF SHOULD BE
GENERALLY SPEAKING ON THE LIGHT SIDE AS OPPOSED TO SOAKING.
WETTEST AREAS WILL BE THE NORTHWEST AND NORTHERN TIER COUNTIES
CLOSEST TO THE PROXIMITY OF THE CUTOFF.
LAST 2-3 MODEL CYCLES HAVE INDICATED A POSSIBLE RETURN TO DRIER
CONDITIONS FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY
ACROSS THE OHIO VALLEY AND INTO PA.
WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES
WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW
DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO
AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL PUSH SLOWLY SOUTHWARD ACROSS NORTHERN PA
EARLY THIS MORNING. WEAK UPPER-LEVEL DISTURBANCES TRANSLATING EWD
FM THE OH VLY WILL CONTINUE TO SUPPORT SHOWERS ACRS THE SRN 1/2 OF
PA. BASED ON LATEST COSPA AND RADAR TRENDS...WILL KEEP MENTION OF
RAIN FOR SOUTH-CENTRAL TAF SITES THRU APPROX 12Z...FOLLOWED BY A
RELATIVE LULL IN PCPN FOR MID-LATE MORNING. FROPA SHOULD OCCUR AT
BFD BEFORE 08Z AND SHIFT WINDS TO THE NORTH...ALLOWING DRY AIR TO
IMPROVE CIGS/VIS TO MVFR. VFR TO MVFR CONDS SHOULD BE COMMON OVR
THE REMAINING AIRFIELDS.
THE FRONTAL BOUNDARY WILL STALL OUT OVR SRN PA THIS AFTN...AND
CONTINUE TO ACT AS A CONDUIT FOR SHOWER ACTIVITY. THERE IS A
RATHER SIGNIFICANT FCST CHANGE LOOMING ON THE HORIZON BASED ON THE
LATEST MODEL DATA...WHICH SUGGESTS MORE WIDESPREAD PCPN ACRS THE
AREA THRU TONIGHT. WILL ADDRESS THIS CHANGE IN SUBSEQUENT TAF SETS.
OUTLOOK...
FRI-SAT...MVFR-IFR BCMG MVFR-VFR.
SUN-MON...SCT SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/LAMBERT
NEAR TERM...DEVOIR/LAMBERT
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
203 AM EDT THU SEP 27 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT OVER NORTHWEST PENNSYLVANIA EARLY THIS
MORNING WILL DRIFT SOUTH ACROSS THE STATE OVERNIGHT AND BECOME
LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER LATER TODAY WHERE
IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS
FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE
SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A
DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN
CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST
STATES THIS WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE
THROUGH KGKJ NEWD THROUGH WARREN AND KELZ THIS HOUR. TO THE SOUTH...
SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION
BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB
JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND
MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST
CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL
AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER
MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG
AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING
SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF
THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND
NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT.
LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT
COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS.
THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF
INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST
SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING
STATIONARY THERE THROUGH THURSDAY NIGHT.
A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3
TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS
OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS
POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS
THE NRN MTNS.
SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE
OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER
50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS
GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL
PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH.
THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE
MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR
MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND
IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER
LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S.
MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF
THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW
DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED
STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A
STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND
CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY
AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE
REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS
RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA.
THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE
THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT
FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE
UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT
LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO
MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST
COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS
LOW.
CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS
FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE
OHIO VALLEY AND INTO PA.
WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES
WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW
DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO
AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL PUSH SLOWLY SOUTHWARD ACROSS NORTHERN PA
EARLY THIS MORNING. WEAK UPPER-LEVEL DISTURBANCES TRANSLATING EWD
FM THE OH VLY WILL CONTINUE TO SUPPORT SHOWERS ACRS THE SRN 1/2 OF
PA. BASED ON LATEST COSPA AND RADAR TRENDS...WILL KEEP MENTION OF
RAIN FOR SOUTH-CENTRAL TAF SITES THRU APPROX 12Z...FOLLOWED BY A
RELATIVE LULL IN PCPN FOR MID-LATE MORNING. FROPA SHOULD OCCUR AT
BFD BEFORE 08Z AND SHIFT WINDS TO THE NORTH...ALLOWING DRY AIR TO
IMPROVE CIGS/VIS TO MVFR. VFR TO MVFR CONDS SHOULD BE COMMON OVR
THE REMAINING AIRFIELDS.
THE FRONTAL BOUNDARY WILL STALL OUT OVR SRN PA THIS AFTN...AND
CONTINUE TO ACT AS A CONDUIT FOR SHOWER ACTIVITY. THERE IS A
RATHER SIGNIFICANT FCST CHANGE LOOMING ON THE HORIZON BASED ON THE
LATEST MODEL DATA...WHICH SUGGESTS MORE WIDESPREAD PCPN ACRS THE
AREA THRU TONIGHT. WILL ADDRESS THIS CHANGE IN SUBSEQUENT TAF SETS.
OUTLOOK...
FRI-SAT...MVFR-IFR BCMG MVFR-VFR.
SUN-MON...SCT SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...DEVOIR/LAMBERT
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1258 AM EDT THU SEP 27 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT OVER NORTHWEST PENNSYLVANIA EARLY THIS
MORNING WILL DRIFT SOUTH ACROSS THE STATE OVERNIGHT AND BECOME
LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER LATER TODAY WHERE
IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS
FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE
SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A
DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN
CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST
STATES THIS WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE
THROUGH KGKJ NEWD THROUGH WARREN AND KELZ THIS HOUR. TO THE SOUTH...
SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION
BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB
JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND
MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST
CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL
AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER
MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG
AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING
SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF
THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND
NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT.
LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT
COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS.
THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF
INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST
SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING
STATIONARY THERE THROUGH THURSDAY NIGHT.
A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3
TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS
OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS
POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS
THE NRN MTNS.
SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE
OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER
50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS
GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL
PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH.
THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE
MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR
MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND
IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER
LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S.
MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF
THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW
DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED
STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A
STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND
CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY
AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE
REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS
RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA.
THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE
THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT
FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE
UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT
LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO
MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST
COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS
LOW.
CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS
FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE
OHIO VALLEY AND INTO PA.
WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES
WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW
DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO
AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL MOVE SLOWLY SOUTH ACROSS THE CWA OVERNIGHT
WITH WEAK MID-LEVEL WAVES CONTINUING TO MOVE W-E OVERHEAD. THIS
WILL KEEP MENTION OF RAIN FOR MOST TAF SITES OVERNIGHT...WITH BEST
LIKELIHOOD IN KJST-KAOO. CIGS ACROSS THE HIGHER TERRAIN ALREADY
MVFR...AND THESE WILL LOWER TO IFR MAINLY AFTER 06Z AS STRATOCU
DECK THICKENS AND SPREADS INTO CENTRAL MTNS AND LOWER SUSQ /LATE/.
KBFD WILL SEE IFR CONDITIONS AROUND FROPA...THEN GRADUAL
IMPROVEMENT AS 12Z APPROACHES AS DRIER AIR BEGINS TO SLIP IN FROM
THE NW.
THE FRONTAL BOUNDARY WILL MOST LIKELY STALL OUT NEAR THE PA/MD
BORDER ON THU. SO THE THREAT OF SHOWERS WILL CONTINUE OVER THE
SOUTHERN THIRD. CIGS WILL BEGIN AT IFR/MVFR BUT GRADUALLY RETURN
TO VFR BY MID/LATE MORNING...WITH INTERMITTENT REDUCTIONS IN
SHOWERS ACROSS THE SOUTH.
OUTLOOK...
FRI-SUN...VFR TO MVFR WITH SCT SHOWERS - MAINLY S AND E.
MON...SHOWERS POSS NW...VFR ELSEWHERE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...DEVOIR/LAMBERT
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1237 AM EDT THU SEP 27 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONTAL BOUNDARY JUST SOUTHEAST OF THE LAKE ERIE
SHORE WILL DRIFT SOUTH ACROSS THE STATE AND BECOME LOCATED NEAR THE
PENNSYLVANIA...MARYLAND BORDER WHERE IT WILL STALL OUT RIGHT INTO
FRIDAY. THE CLOSE PROXIMITY OF THIS FRONT WILL MAINTAIN THE THREAT
OF OCCASIONAL RAIN OVER THE SOUTHERN THIRD OF THE KEYSTONE STATE FOR
THURSDAY AND FRIDAY. A DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP
SOUTHWARD FROM EASTERN CANADA AND CARVE OUT OVER THE GREAT LAKES
REGION AND NORTHEAST STATES THIS WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE
THROUGH KGKJ NEWD THROUGH KBFD AND KELZ THIS HOUR. TO THE SOUTH...
SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION
BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB
JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND
MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST
CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL
AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER
MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG
AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING
SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF
THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND
NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT.
LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT
COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS.
THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF
INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST
SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING
STATIONARY THERE THROUGH THURSDAY NIGHT.
A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3
TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS
OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS
POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS
THE NRN MTNS.
SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE
OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER
50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS
GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL
PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH.
THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE
MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR
MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND
IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER
LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S.
MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF
THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW
DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED
STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A
STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND
CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY
AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE
REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS
RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA.
THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE
THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT
FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE
UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT
LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO
MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST
COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS
LOW.
CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS
FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE
OHIO VALLEY AND INTO PA.
WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES
WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW
DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO
AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A FRONTAL BOUNDARY WILL MOVE SLOWLY SOUTH ACROSS THE CWA OVERNIGHT
WITH WEAK MID-LEVEL WAVES CONTINUING TO MOVE W-E OVERHEAD. THIS
WILL KEEP MENTION OF RAIN FOR MOST TAF SITES OVERNIGHT...WITH BEST
LIKELIHOOD IN KJST-KAOO. CIGS ACROSS THE HIGHER TERRAIN ALREADY
MVFR...AND THESE WILL LOWER TO IFR MAINLY AFTER 06Z AS STRATOCU
DECK THICKENS AND SPREADS INTO CENTRAL MTNS AND LOWER SUSQ /LATE/.
KBFD WILL SEE IFR CONDITIONS AROUND FROPA...THEN GRADUAL
IMPROVEMENT AS 12Z APPROACHES AS DRIER AIR BEGINS TO SLIP IN FROM
THE NW.
THE FRONTAL BOUNDARY WILL MOST LIKELY STALL OUT NEAR THE PA/MD
BORDER ON THU. SO THE THREAT OF SHOWERS WILL CONTINUE OVER THE
SOUTHERN THIRD. CIGS WILL BEGIN AT IFR/MVFR BUT GRADUALLY RETURN
TO VFR BY MID/LATE MORNING...WITH INTERMITTENT REDUCTIONS IN
SHOWERS ACROSS THE SOUTH.
OUTLOOK...
FRI-SUN...VFR TO MVFR WITH SCT SHOWERS - MAINLY S AND E.
MON...SHOWERS POSS NW...VFR ELSEWHERE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...DEVOIR/LAMBERT
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
426 AM CDT THU SEP 27 2012
.DISCUSSION...
CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN
ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST
ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND
HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE
TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE
I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT
MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED
ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE
COLD FRONT BEGINS TO MOVE SOUTH.
THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND
INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS
INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE
INHIBITION.
THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND
SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY
SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO
THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S.
MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO
VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES
ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME
THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE
MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI
VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER
CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO
BE AROUND NORMAL.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 83 64 79 61 / 20 60 60 20
CLARKSVILLE 82 60 77 59 / 90 70 50 20
CROSSVILLE 79 60 75 57 / 20 60 60 20
COLUMBIA 85 63 81 62 / 20 30 60 30
LAWRENCEBURG 85 60 82 62 / 10 20 60 30
WAVERLY 83 61 79 59 / 60 60 60 20
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
231 AM CDT THU SEP 27 2012
.DISCUSSION...
A STALLED FRONT REMAINS LOCATED ACROSS SOUTHERN MISSOURI THIS
MORNING. SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG
THE BOUNDARY. LATEST HRRR MODEL INDICATES THESE SHOWERS AND
THUNDERSTORMS WILL BEGIN MOVING SOUTHEAST INTO THE CWA. LOOKING AT
LATEST RADAR IMAGES...BEGINNING TO SEE INDIVIDUAL STORMS MOVING TO
THE SOUTHEAST. AS A RESULT...WILL CONTINUE WITH LIKELY POPS ACROSS
NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND NORTHWEST
TENNESSEE INTO THE MORNING HOURS. HRRR SHOWS ACTIVITY DYING OUT
BY NOON TIME. DURING THE AFTERNOON...REDEVELOPMENT WILL LIKELY
OCCUR ACROSS SOUTHERN MISSOURI NEAR THE FRONT. SOME OF THE
ACTIVITY COULD SKIRT NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL
AND EXTREME NORTHWEST TENNESSEE. WILL GO WITH 40 POPS IN THE
AFTERNOON FOR THESE AREAS. ELSEWHERE...CONDITIONS SHOULD STAY DRY.
ALTHOUGH...MAY SEE MOSTLY CLOUDY CONDITIONS MAINLY FROM BLOW OFF
FROM CONVECTION OCCURRING TO THE NORTH OR WEST. HIGHS WILL BE IN
THE 80S.
TONIGHT...EXPECT WHATEVER ACTIVITY THAT DEVELOPS THIS AFTERNOON
ACROSS SOUTHERN MISSOURI TO BEGIN SPREADING SOUTHWARD INTO THE CWA
AS MODELS INDICATE FRONT MAY START MOVING TO THE SOUTH. BEST CHANCES
WILL OCCUR ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND
WEST TENNESSEE. LOWS WILL BE IN THE 60S.
FRIDAY AND FRIDAY NIGHT...FRONT PUSHES INTO THE CWA THUS EXPECT
CHANCES FOR SHOWERS AND THUNDERSTORMS TO SPREAD ACROSS THE ENTIRE
CWA. HOWEVER...EXPECT RAINFALL AMOUNTS TO REMAIN ON THE LIGHT SIDE.
THE WEEKEND...BY SATURDAY MORNING...COOLER AND DRIER AIR WILL BEGIN
SPREADING INTO PORTIONS OF NORTHWEST TENNESSEE. EXPECT FRONT TO
LIKELY BE LOCATED JUST TO THE SOUTH OF THE CWA. HOWEVER STILL EXPECT
SOME POST FRONTAL RAIN TO OCCUR MAINLY OVER NORTH MISSISSIPPI AND
EAST CENTRAL ARKANSAS. BY SATURDAY NIGHT INTO SUNDAY...EXPECT COOLER
AND DRIER AIR TO HAVE FILTERED INTO MUCH OF THE CWA WITH ONLY
EXTREME SOUTHERN PORTIONS OF THE CWA SEEING CONTINUING CHANCES FOR
RAIN.
MONDAY THROUGH WEDNESDAY...A BROAD UPPER TROF WILL REMAIN OVER THE
MIDSOUTH. MODELS KEEP FLIPPING BACK AND FORTH ON WHETHER A CLOSED
UPPER LOW FORMS. A SFC LOW IS EXPECTED TO DEVELOP ALONG THE GULF
COAST. DEPENDING ON THE LOCATION OF THE LOW...SOME RAIN COULD SPREAD
NORTHWARD INTO NORTHEAST MISSISSIPPI AS IT PUSHES EAST. FOR NOW WILL
CONTINUE WITH DRY FORECAST UNTIL MODELS SHOW SOME CONSISTENCY.
KRM
&&
.AVIATION...
06Z TAFS
LIGHT WINDS AND VFR CONDITIONS ARE EXPECTED THROUGHOUT THE ENTIRE
FORECAST AREA THROUGH THE PERIOD. FRONTAL BOUNDARY LOOKS TO START
TO SLIDE SLOWLY ACROSS THE FORECAST AREA...ALLOWING FOR SOME
THUNDERSTORMS TOMORROW ACROSS THE REGION BUT HAVE NOT ADDED CB OR
TEMPO GROUPS AS OF YET WITH THE COVERAGE BEING ISOLATED TO SCTD
ACROSS THE AREA MOST LIKELY AND EXACT INITIATION TIME OF STORMS NOT
CLEAR. --ABS
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 85 69 83 65 / 20 30 50 30
MKL 84 63 81 59 / 30 40 60 20
JBR 83 64 79 59 / 60 60 60 40
TUP 87 66 86 63 / 10 10 40 30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1204 AM CDT THU SEP 27 2012
.UPDATE...
MAIN REASON FOR UPDATE WAS THE CANCEL THE REMAINDER OF SEVERE
THUNDERSTORM WATCH 653 FROM THE REMAINDER OF THE TEXAS AND OKLAHOMA
PANHANDLES. REMAINDER OF THE FORECAST LOOKS TO BE ON TRACK WITH NO
OTHER UPDATES NEEDED.
&&
.AVIATION...
/06Z TAFS/ MAIN CONCERN FOR THIS FORECAST PERIOD CENTERS ON FOG/LOW
CLOUDS AT KDHT/KGUY AND WHEN SHOWERS AND THUNDERSTORMS WILL AFFECT
THE TERMINALS. ONGOING CONVECTION ACROSS THE EASTERN OKLAHOMA
PANHANDLE AND THE NORTHEAST TEXAS PANHANDLE CONTINUES TO PUSH OFF TO
THE EAST INTO WESTERN OKLAHOMA. CONVECTIVE TRENDS SHOW STORMS
CONTINUING TO WEAKEN AS INSTABILITY CONTINUES TO WEAKEN ACROSS THE
AREA. LATEST TTU WRF AND HRRR STILL SUGGEST AREA OF SHOWERS AND
THUNDERSTORMS CURRENTLY IN EASTERN NEW MEXICO WILL MOVE INTO THE
SOUTHERN TEXAS PANHANDLE OVERNIGHT. HOWEVER HAVE NOT INCLUDED TSRA
MENTION IN THE KAMA TERMINAL DUE TO LOW CONFIDENCE IN THESE STORMS
HOLDING TOGETHER AS THEY MOVE TOWARD KAMA. A FRONTAL BOUNDARY WAS
SLIDING SOUTH INTO THE NORTHERN TEXAS PANHANDLE TONIGHT WHERE ITS
EXPECTED TO STALL OVERNIGHT. LOW LEVEL MOISTURE WITH LIGHT UPSLOPE
WINDS BEHIND THE FRONT MAY LEAD TO THE DEVELOPMENT OF LOW CLOUDS AND
FOG AT KGUY/KDHT...WITH MVFR VISBYS AND CIGS. HAVE KEPT VFR
CONDITIONS IN AT KAMA ALTHOUGH THERE IS A POSSIBILITY FOR LOW CLOUDS
TO DEVELOP THURSDAY MORNING. THUNDERSTORMS MAY AFFECT ALL THREE TERMINALS
THURSDAY HOWEVER TIMING AND LOCATION OF ANY STORMS IS UNCERTAIN SO
HAVE OPTED TO KEPT OUT MENTION IN THE FORECAST.
CLK
&&
.PREV DISCUSSION... /ISSUED 1002 PM CDT WED SEP 26 2012/
UPDATE...
HAVE REMOVED SEVERE THUNDERSTORM WATCH FROM CIMARRON...DALLAM...
HARTLEY...AND SHERMAN COUNTIES FROM SEVERE THUNDERSTORM WATCH 653 AS
THE ATMOSPHERE HAS STABILIZED WITH TEMPS COOLING DOWN INTO THE MID TO
UPPER 50S. COMPLEX OF STRONG TO SEVERE THUNDERSTORMS CONTINUES TO
MOVE ACROSS THE CENTRAL AND EASTERN OKLAHOMA PANHANDLE AND AN OUTFLOW
BOUNDARY WAS RACING SOUTHWARD FROM THESE STORMS. HAVE OPTED TO LEAVE
THE WATCH IN EFFECT FOR THE REMAINDER OF THE PANHANDLES UNTIL 11 PM
AS THIS OUTFLOW BOUNDARY MAY PROVIDE A FOCUS FOR STORMS. HAVE ALSO
ADJUSTED LOW TEMPS DOWN A FEW DEGREES IN THE NORTHWEST ZONES. UPDATED
TEXT PRODUCTS HAVE BEEN SENT.
CLK
PREV DISCUSSION... /ISSUED 718 PM CDT WED SEP 26 2012/
AVIATION...
/00Z TAFS/ COMPLEX AVIATION FORECAST SHAPING UP OVER THE NEXT 24
HOURS. ONGOING CONVECTION IS CURRENTLY NORTH AND WEST OF KGUY/KDHT
AND WELL EAST OF THE KAMA TERMINAL. CURRENT RADAR REFLECTIVITY
IMAGERY SHOWS ADDITIONAL DEVELOPMENT IN EASTERN NEW MEXICO WHICH THE
18Z TTU WRF AND 21Z HRRR ARE DEPICTING THIS INCREASING IN COVERAGE
AS IT MOVES ACROSS THE PANHANDLES LATER TONIGHT. HAVE KEPT IN PREVIOUS
MENTION OF -SHRA AS COOLING BOUNDARY LAYER TEMPS SHOULD LIMIT THE
INSTABILITY AND THUS LOWER THE CHANCES FOR THUNDER DEVELOPMENT. LOW
CLOUDS AND FOG ARE POSSIBLE AT KGUY/KDHT THURSDAY MORNING WHERE A
LITTLE BETTER LOW LEVEL MOISTURE WILL RESIDE. HOWEVER HAVE KEPT
CONDITIONS AT MVFR AS CONFIDENCE IS NOT TOO HIGH THAT WORSENING
CONDITIONS WILL DEVELOP. HAVE KEPT A VFR FORECAST IN AT KAMA BUT MAY
HAVE TO AMEND IF TRENDS SUGGEST CIGS AND/OR VISBYS LOWERING BELOW
MVFR. STORMS CAN DEVELOP AT THE TERMINALS THURSDAY BUT HAVE OPTED TO
LEAVE MENTION OUT OF THE TAFS DUE TO LOW CONFIDENCE ON TIMING AND
WHERE STORMS WILL DEVELOP.
CLK
PREV DISCUSSION... /ISSUED 351 PM CDT WED SEP 26 2012/
DISCUSSION...
THROUGH TONIGHT: A RATHER COMPLICATED AND SOMEWHAT LOW CONFIDENCE
FORECAST HAS EVOLVED TODAY. A WEAK SURFACE TROUGH CURRENTLY STRETCHES
FROM THE SOUTHERN TEXAS PANHANDLE TO NEAR THE RED RIVER. IN THE
UPPER-LEVELS A CLOSED LOW CONTINUES TO SPIN OVER THE WESTERN COLORADO
WITH A SUBTLE SHORTWAVE TROUGH...EJECTING OUT OF THIS LOW...NOW
APPROACHING EASTERN NEW MEXICO. LARGE SCALE FORCING FOR ASCENT WILL
BE ON THE INCREASE THROUGH THIS EVENING...AND WE EXPECT ISOLATED TO
WIDELY SCATTERED CONVECTION TO INITIATE SOUTH AND WEST OF A BOISE CITY
TO SHAMROCK LINE THROUGH 7 PM. A LOOSELY ORGANIZED COMPLEX OF STORMS
MAY EVOLVE AFTER 11 PM ALONG AND EAST OF A GUYMON TO CLARENDON LINE
AND STEADILY MARCH EASTWARD OVERNIGHT. BASED ON THIS SCENARIO...WE
THINK THE HIGHEST SEVERE WEATHER CHANCES WILL BE THROUGH MIDNIGHT.
MIXED LAYER CAPE VALUES WILL BE UP TO 2000 J/KG IN THE SOUTHEAST WITH
EFFECTIVE BULK SHEAR VALUES UP TO 45 KT ACROSS MOST OF THE AREA. AS A
RESULT...LARGE HAIL UP TO THE SIZE OF HALF DOLLARS AND DAMAGING
WINDS IN EXCESS OF 60 MPH WILL BE THE PRIMARY HAZARDS. THE HAIL
THREAT WILL LIKELY BE HIGHEST ACROSS THE SOUTHEAST TEXAS PANHANDLE
WHERE THE AIR MASS IS MOST UNSTABLE AND HAIL GROWTH CAPE VALUES WILL
BE AS HIGH AS 600 J/KG. BELIEVE THE ATMOSPHERE WILL BE WORKED OVER
ENOUGH OVERNIGHT THAT THIS MAY LIMIT THE COVERAGE OF ADDITIONAL
THUNDERSTORMS. THEREFORE...WE LOWERED POPS FOR THE OVERNIGHT HOURS.
THURSDAY-THURSDAY NIGHT: ANOTHER TRICKY FORECAST IS IN STORE FOR
TOMORROW AND THE BEST THUNDERSTORM CHANCES WILL LARGELY DEPEND ON
WHERE THE SURFACE FRONT SETS UP. THE NAM AND ECMWF KEEP THE FRONT
JUST NORTH OF INTERSTATE 40 WHILE THE GFS AND GGEM KEEP THE FRONT
ACROSS THE NORTHERN TEXAS PANHANDLE. EXTENSIVE LOW CLOUDS WILL ALSO
COMPLICATE HIGH TEMPERATURES DURING THE AFTERNOON WITH HIGHS NEAR 70
EXPECTED IN THE NORTHWEST AND MID 70S IN THE SOUTHEAST. THESE LOW
CLOUDS WILL ALSO HAVE A LARGE IMPACT ON HOW UNSTABLE THE ATMOSPHERE
CAN BECOME. IF THE LOW CLOUDS ARE STUBBORN TO BREAK...THIS COULD LEAD
TO A VERY MARGINAL SEVERE WEATHER EVENT. AT THIS TIME..WE THINK THERE
WILL BE ENOUGH BREAKS IN THE CLOUDS TO DESTABILIZE THE ATMOSPHERE
SUFFICIENTLY FOR SEVERE STORMS. IN FACT...A FEW SEVERE STORMS CANNOT
BE RULED OUT JUST ABOUT ANYWHERE DURING THE AFTERNOON AND
EVENING...BUT THE HIGHER PROBABILITIES LOOK TO EXIST SOUTH OF A
DALHART TO CANADIAN LINE. DEEP LAYER BULK SHEAR VALUES WILL RANGE
BETWEEN 30 AND 40 KT ALONG WITH MIXED LAYER CAPE VALUES UP TO 1000
J/KG. AS A RESULT...LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY
HAZARDS. MORE WIDESPREAD RAIN CHANCES LOOK TO EVOLVE DURING THE LATE
EVENING AND OVERNIGHT HOURS. LOCALLY HEAVY RAIN WILL ALSO CONTINUE TO
BE A CONCERN.
FRIDAY-WEDNESDAY: THUNDERSTORMS CHANCES WILL CONTINUE THROUGH SUNDAY
NIGHT BEFORE DRIER CONDITIONS RETURN FOR EARLY NEXT WEEK. NO SEVERE
WEATHER IS ANTICIPATED DURING THIS TIME FRAME AS THE ENVIRONMENT
SHOULD BE WEAKLY UNSTABLE ALONG WITH POOR DEEP LAYER WIND SHEAR IN
PLACE. TEMPERATURES WILL BE NEAR TO BELOW NORMAL FRIDAY AND SATURDAY
BEFORE A WARMING TREND BEGINS SUNDAY.
JACKSON
FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
THROUGH WEDNESDAY AS 20-FOOT WINDS WILL REMAIN BELOW 15 MPH AND/OR
RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE 20 PERCENT.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
438 AM EDT THU SEP 27 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY
SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL
TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED
STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 420 AM EDT WEDNESDAY...
THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA.
MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE
ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE
FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS
OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT
LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION
INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z.
OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE
SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE
WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE
MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN
BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT.
TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING.
WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE
NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS
THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO
LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 340 AM EDT THURSDAY...
MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST
MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY
AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ.
MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO
SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA
DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND
EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE
ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE
VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING.
CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN
THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE
AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY
NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH
AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST.
RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES
COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL.
LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH
TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING
OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY
WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 245 PM EDT WEDNESDAY...
FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH
OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND
EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE
ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO
DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE
TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION.
THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY
NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH
THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL
APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK
THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE
GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL
TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN
EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE
OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH
SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AS OF 135 AM EDT THURSDAY...
MID AND HIGH CLOUDS COMING FROM THE THUNDERSTORMS IN THE OHIO
VALLEY MAY LIMIT THE EXTENT OF THE FOG THIS MORNING. HOWEVER...
OBSERVATIONS ALREADY SHOWED A SMALL TEMPERATURE/DEW POINT SPREAD
AT AREA AIRPORTS. HAVE LEFT MVFR FOG IN EARLY THIS MORNING FOR
LYH...DAN AND BCB. MODERATE CONFIDENCE THAT LWB WILL OCCASIONALLY
DROP TO LIFR VISIBILITY AND CEILINGS.
PERSISTENT BAROCLINIC ZONE TO THE NORTH OF THE AREA WILL DRIFT
INTO THE CWA DURING THE AFTERNOON. THUNDERSTORMS APPEAR TO BE A
GOOD BET FOR MUCH OF THE CWA BY LATE AFTERNOON. LOCATION OF THE
SURFACE COLD FRONT WILL HAVE A BIG INFLUENCE ON THE PROBABILITY OF
SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA THIS AFTERNOON AND
TONIGHT.
AT THIS POINT...ALL AREAS SHOULD SEE SHRA/TSRA ACTIVITY IN THE
20Z-06Z TIME FRAME FROM W-E...WITH THE MOST INTENSE ACTIVITY
LIKELY FROM LWB-BLF IN THE LATE AFTERNOON.
MVFR CONDITIONS AND A GREATER COVERAGE OF SHOWERS AND STORMS ARE
EXPECTED TONIGHT INTO THE START OF THE WEEKEND AS THE FRONT MOVES INTO
THE REGION...STALLS...AND THEN HEADS SOUTH OF THE AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...AMS
SHORT TERM...RCS
LONG TERM...WP
AVIATION...AMS/RAB
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1056 AM EDT THU SEP 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS THE REGION TODAY. SEVERAL WAVES OF
LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY THROUGH
THE WEEKEND. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO MOVE OUT
OF THE GREAT LAKES REGION INTO NEW ENGLAND SUNDAY INTO MONDAY BEFORE
HIGH PRESSURE MOVES ACROSS OUR AREA. THIS MAY HELP MOVE THE
FRONTAL BOUNDARY ALONG AND PROVIDE DRIER WEATHER TUESDAY INTO
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RATHER NARROW AND QUITE SPOTTY BAND OF SHOWERS RUNNING ACROSS
THE FORECAST AREA MAINLY NORTH OF A MQS TO PHL TO BLM LINE AT MID
MORNING LIKELY WAS TIED TO SOME WEAKENING AND CHANNELED H5
VORTICITY STRINGING ALONG OVER THE AREA. THE HRRR GUIDANCE, AS
OFTEN IS THE CASE, HAS NOT BEEN HANDLING THIS CONSISTENTLY. THE
NEW NAM20 TAKES THE VORTICITY AWAY BY AROUND NOON. ONLY SOME
ISOLATED NUISANCE SHOWERS ARE FORECAST FOR THE BALANCE OF THE
AFTERNOON CENTRAL AND NORTH, AND LITTLE OR NO THREAT OF ANY
MORNING ACTIVITY IS FORECAST SOUTH.
MEANWHILE, A MID LEVEL SHORT WAVE MOVING OUT OF INDIANA THIS
MORNING WILL MOVE EAST AND IS EXPECTED TO REACH WESTERN
PENNSYLVANIA THIS EVENING. A WEAK SURFACE LOW ASSOCIATED WITH THE
SHORT WAVE ALSO WILL APPROACH DURING THE COURSE OF THE DAY.
AFTER CARVING OUT A FEW HOURS CENTERED AROUND NOON WITH NO RAIN
FORECAST, WE CARRY INCREASING CHANCES DURING THE AFTERNOON FROM
WEST TO EAST, BUT THOSE CHANCES DON`T EXCEED THE LOW CHANCE RANGE.
WITH MARGINAL INSTABILITY FOR THE MID TO LATE AFTERNOON HOURS, WE
MENTION SCATTERED TO ISOLATED RAIN SHOWERS ALONG WITH THE
POTENTIAL FOR ISOLATED THUNDERSTORMS.
WITH SOME SUNSHINE EXPECTED THROUGH THE CLOUDS TODAY, AFTERNOON
TEMPERATURES ARE FORECAST TO RISE INTO THE MIDDLE 70S TO THE LOWER
80S. READINGS IN OUR NORTHERN COUNTIES MAY GET NO HIGHER THAN THE
UPPER 60S AND THE LOWER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
FOR TONIGHT, THE MID LEVEL SHORT WAVE IS EXPECTED TO PROGRESS
FROM OHIO TO CENTRAL PENNSYLVANIA. THE SURFACE LOW IS FORECAST TO
REACH PENNSYLVANIA`S SUSQUEHANNA RIVER VALLEY LATE TONIGHT. A PUSH
OF WARM MOIST AIR AHEAD OF THE SYSTEM WILL LIKELY RESULT IN RAIN
OVERSPREADING MUCH OF OUR REGION TONIGHT. BASED ON THE LATEST
MODEL GUIDANCE, IT APPEARS AS THOUGH THE BETTER CHANCES FOR RAIN
AND THE HIGHER RAINFALL AMOUNTS SHOULD BE ACROSS EASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY WITH SOMEWHAT LOWER NUMBERS
FOR SOUTHERN NEW JERSEY AND FOR THE UPPER DELMARVA. WE WILL
CONTINUE TO MENTION A SLIGHT CHANCE OF THUNDERSTORMS WITH SOME
MARGINAL INSTABILITY LINGERING AND THE INCREASING LIFT DUE TO THE
APPROACHING SYSTEM FROM THE WEST.
WITH THE CLOUD COVER AND A LIGHT EAST TO SOUTHEAST FLOW, MINIMUM
TEMPERATURES SHOULD DROP ONLY INTO THE UPPER 50S TO THE MIDDLE 60S
FOR TONIGHT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
UNSETTLED WEATHER CONTINUES TO BE FORECAST FOR THE END OF THE
WEEK INTO THE WEEKEND, BEFORE A POSSIBLE DRYING OUT PERIOD. ON
FRIDAY, AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE
FRONTAL BOUNDARY THAT CROSSES THE AREA TODAY AND STALLS TO OUR
SOUTH. ALL MODEL GUIDANCE IS FORECASTING THE LOW TO TRACK RIGHT
ACROSS OUR AREA ON FRIDAY. FORECAST QPFS ARE HIGHEST ACROSS OUR
NORTHERN ZONES AND FURTHER NORTH OF OUR AREA SINCE THE STRONGEST
FORCING FROM THE SHORT WAVE/VORT MAX ALOFT ARE FURTHER NORTH. WE
HAVE KEPT THE SLIGHT CHANCE OF THUNDERSTORMS IN THE FORECAST SINCE
THERE IS STILL SOME INSTABILITY FORECAST. AREAS ON THE NORTHERN
SIDE OF THE LOW PRESSURE HAVE LESS OF A CHANCE THAN AREAS FURTHER
SOUTH.
BY FRIDAY NIGHT INTO SATURDAY, IT IS POSSIBLE THAT THE FRONTAL
BOUNDARY MAY PUSH FAR ENOUGH SOUTH AND EAST OF THE AREA THAT WE
MAY HAVE A BRIEF DRYING PERIOD. HOWEVER, DUE TO THE CLOSENESS OF
THE FRONT AND THE FACT MULTIPLE DISTURBANCES ALOFT WILL AFFECT THE
AREA, WE WILL KEEP A CHANCE OF PRECIPITATION FOR AT LEAST THE
EASTERN PORTION OF THE AREA.
SUNDAY BRINGS ANOTHER ENHANCED PROBABILITY OF PRECIPITATION
ACROSS THE AREA. A CLOSED LOW ALOFT AND ITS SURFACE LOW ARE
FORECAST TO MOVE OUT OF CANADA AND INTO THE GREAT LAKES, BEFORE
MOVING INTO NEW ENGLAND SUNDAY INTO SUNDAY NIGHT. THIS MAY BRING
ENOUGH MOISTURE AND LIFT ACROSS THE AREA TO PROVIDE A FOCUS FOR
ADDITIONAL SHOWERS TO OCCUR. THE GREATEST PROBABILITY MAY BE NORTH
OF OUR AREA, BUT WE KEEP A CHANCE OF SHOWERS THROUGH SUNDAY NIGHT.
WITH NOT MUCH INSTABILITY EXPECTED, THUNDER WAS LEFT OUT OF THE
FORECAST.
WE MAY THEN GET A DRYING OUT PERIOD AS WE GO INTO EARLY NEXT
WEEK. THERE MAY BE A FEW LINGERING SHOWERS EARLY MONDAY AS THE
AFOREMENTIONED LOW PULLS AWAY FROM THE AREA, BUT AFTER THAT, HIGH
PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TUESDAY INTO
WEDNESDAY.
TEMPERATURES THROUGH THE EXTENDED ARE EXPECTED TO BE A FEW
DEGREES ABOVE NORMAL, WITH THE WEEKEND BEING THE COOLEST WHICH MAY
END UP BEING VERY CLOSE TO NORMAL.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE STALLING FRONT AND THE STRING OF SPOTTY SHOWER ACTIVITY THIS
MORNING WAS MAKING IT DIFFICULT FOR SITES FROM PHL NORTH TO
CONSISTENTLY RISE OUT OF THE MVFR OR IFR RANGE. WE PRESENTLY ARE
FORECASTING THAT ACTIVITY TO DISSIPATE BY AROUND 16Z OR 17Z.
CONFIDENCE IN THIS IS LOW TO MODERATE. SOUTH OF PHL, OUR FORECAST
IS FOR VFR CONDITIONS FOR THE BALANCE OF THE DAY. CONFIDENCE IN
THIS IS MODERATE.
WEAK LOW PRESSURE APPROACHING FROM THE WEST IS FORECAST TO SPREAD
RAIN INTO OUR REGION FOR TONIGHT. CONDITIONS ARE EXPECTED TO LOWER
INTO THE MVFR CATEGORY AT MOST LOCATIONS. BRIEF PERIODS OF IFR ARE
POSSIBLE IN POCKETS OF MODERATE TO HEAVY RAIN, ESPECIALLY AT KRDG
AND KABE.
ANY THUNDERSTORM ACTIVITY FOR THIS AFTERNOON INTO TONIGHT SHOULD
BE VERY ISOLATED AND IT WILL NOT BE MENTIONED IN THE TAFS.
THE WIND IS FORECAST TO BE MOSTLY AT 8 KNOTS OR LESS FOR TODAY AT
VARYING DIRECTIONS. THE WIND SHOULD SETTLE INTO THE EAST TO SOUTH
QUADRANT FOR TONIGHT AT SPEEDS OF 10 KNOTS OR LESS.
OUTLOOK...
FRIDAY...PERIODS OF RAIN WITH MVFR/IFR CONDITIONS EXPECTED.
FRIDAY NIGHT-SATURDAY...CONDITIONS POSSIBLY IMPROVING TO
VFR...STILL A CHANCE OF MVFR CONDITIONS.
SATURDAY NIGHT-SUNDAY NIGHT...PERIODS OF RAIN WITH MVFR/IFR
CONDITIONS POSSIBLE.
MONDAY...CONDITIONS IMPROVING TO VFR.
&&
.MARINE...
A WEAK FRONTAL BOUNDARY FROM THE NORTHWEST WILL DROP INTO OUR
REGION FOR TODAY. WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM
THE WEST FOR TONIGHT. WIND SPEEDS AND WAVE HEIGHTS ARE ANTICIPATED
TO REMAIN BELOW THE SMALL CRAFT ADVISORY CRITERIA DURING TODAY AND
TONIGHT.
OUTLOOK...
THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN STALLED ACROSS THE
AREA THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. WINDS MAY
PERIODICALLY GUST AROUND 15-20 KNOTS. HOWEVER, WINDS AND WAVES ARE
EXPECTED TO REMAIN BELOW ADVISORY LEVELS. SEVERAL WAVES OF LOW
PRESSURE MAY DEVELOP ALONG THE BOUNDARY, WHICH WILL HAVE AN EFFECT
ON WIND DIRECTION.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ROBERTSON/DELISI
NEAR TERM...IOVINO/DELISI
SHORT TERM...IOVINO
LONG TERM...ROBERTSON
AVIATION...IOVINO/ROBERTSON/DELISI
MARINE...IOVINO/ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1007 AM EDT THU SEP 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS THE REGION TODAY. SEVERAL WAVES OF
LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY THROUGH
THE WEEKEND. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO MOVE OUT
OF THE GREAT LAKES REGION INTO NEW ENGLAND SUNDAY INTO MONDAY BEFORE
HIGH PRESSURE MOVES ACROSS OUR AREA. THIS MAY HELP MOVE THE
FRONTAL BOUNDARY ALONG AND PROVIDE DRIER WEATHER TUESDAY INTO
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RATHER NARROW AND QUITE SPOTTY BAND OF SHOWERS RUNNING ACROSS
THE FORECAST AREA MAINLY NORTH OF A MQS TO PHL TO BLM LINE AT MID
MORNING LIKELY WAS TIED TO SOME WEAKENING AND CHANNELED H5
VORTICITY STRINGING ALONG OVER THE AREA. THE HRRR GUIDANCE, AS
OFTEN IS THE CASE, HAS NOT BEEN HANDLING THIS CONSISTENTLY. THE
NEW NAM20 TAKES THE VORTICITY AWAY BY AROUND NOON. ONLY SOME
ISOLATED NUISANCE SHOWERS ARE FORECAST FOR THE BALANCE OF THE
AFTERNOON CENTRAL AND NORTH, AND LITTLE OR NO THREAT OF ANY
MORNING ACTIVITY IS FORECAST SOUTH.
MEANWHILE, A MID LEVEL SHORT WAVE MOVING OUT OF INDIANA THIS
MORNING WILL MOVE EAST AND IS EXPECTED TO REACH WESTERN
PENNSYLVANIA THIS EVENING. A WEAK SURFACE LOW ASSOCIATED WITH THE
SHORT WAVE ALSO WILL APPROACH DURING THE COURSE OF THE DAY.
AFTER CARVING OUT A FEW HOURS CENTERED AROUND NOON WITH NO RAIN
FORECAST, WE CARRY INCREASING CHANCES DURING THE AFTERNOON FROM
WEST TO EAST, BUT THOSE CHANCES DON`T EXCEED THE LOW CHANCE RANGE.
WITH MARGINAL INSTABILITY FOR THE MID TO LATE AFTERNOON HOURS, WE
MENTION SCATTERED TO ISOLATED RAIN SHOWERS ALONG WITH THE
POTENTIAL FOR ISOLATED THUNDERSTORMS.
WITH SOME SUNSHINE EXPECTED THROUGH THE CLOUDS TODAY, AFTERNOON
TEMPERATURES ARE FORECAST TO RISE INTO THE MIDDLE 70S TO THE LOWER
80S. READINGS IN OUR NORTHERN COUNTIES MAY GET NO HIGHER THAN THE
UPPER 60S AND THE LOWER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
FOR TONIGHT, THE MID LEVEL SHORT WAVE IS EXPECTED TO PROGRESS
FROM OHIO TO CENTRAL PENNSYLVANIA. THE SURFACE LOW IS FORECAST TO
REACH PENNSYLVANIA`S SUSQUEHANNA RIVER VALLEY LATE TONIGHT. A PUSH
OF WARM MOIST AIR AHEAD OF THE SYSTEM WILL LIKELY RESULT IN RAIN
OVERSPREADING MUCH OF OUR REGION TONIGHT. BASED ON THE LATEST
MODEL GUIDANCE, IT APPEARS AS THOUGH THE BETTER CHANCES FOR RAIN
AND THE HIGHER RAINFALL AMOUNTS SHOULD BE ACROSS EASTERN
PENNSYLVANIA AND NORTHERN NEW JERSEY WITH SOMEWHAT LOWER NUMBERS
FOR SOUTHERN NEW JERSEY AND FOR THE UPPER DELMARVA. WE WILL
CONTINUE TO MENTION A SLIGHT CHANCE OF THUNDERSTORMS WITH SOME
MARGINAL INSTABILITY LINGERING AND THE INCREASING LIFT DUE TO THE
APPROACHING SYSTEM FROM THE WEST.
WITH THE CLOUD COVER AND A LIGHT EAST TO SOUTHEAST FLOW, MINIMUM
TEMPERATURES SHOULD DROP ONLY INTO THE UPPER 50S TO THE MIDDLE 60S
FOR TONIGHT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
UNSETTLED WEATHER CONTINUES TO BE FORECAST FOR THE END OF THE
WEEK INTO THE WEEKEND, BEFORE A POSSIBLE DRYING OUT PERIOD. ON
FRIDAY, AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE
FRONTAL BOUNDARY THAT CROSSES THE AREA TODAY AND STALLS TO OUR
SOUTH. ALL MODEL GUIDANCE IS FORECASTING THE LOW TO TRACK RIGHT
ACROSS OUR AREA ON FRIDAY. FORECAST QPFS ARE HIGHEST ACROSS OUR
NORTHERN ZONES AND FURTHER NORTH OF OUR AREA SINCE THE STRONGEST
FORCING FROM THE SHORT WAVE/VORT MAX ALOFT ARE FURTHER NORTH. WE
HAVE KEPT THE SLIGHT CHANCE OF THUNDERSTORMS IN THE FORECAST SINCE
THERE IS STILL SOME INSTABILITY FORECAST. AREAS ON THE NORTHERN
SIDE OF THE LOW PRESSURE HAVE LESS OF A CHANCE THAN AREAS FURTHER
SOUTH.
BY FRIDAY NIGHT INTO SATURDAY, IT IS POSSIBLE THAT THE FRONTAL
BOUNDARY MAY PUSH FAR ENOUGH SOUTH AND EAST OF THE AREA THAT WE
MAY HAVE A BRIEF DRYING PERIOD. HOWEVER, DUE TO THE CLOSENESS OF
THE FRONT AND THE FACT MULTIPLE DISTURBANCES ALOFT WILL AFFECT THE
AREA, WE WILL KEEP A CHANCE OF PRECIPITATION FOR AT LEAST THE
EASTERN PORTION OF THE AREA.
SUNDAY BRINGS ANOTHER ENHANCED PROBABILITY OF PRECIPITATION
ACROSS THE AREA. A CLOSED LOW ALOFT AND ITS SURFACE LOW ARE
FORECAST TO MOVE OUT OF CANADA AND INTO THE GREAT LAKES, BEFORE
MOVING INTO NEW ENGLAND SUNDAY INTO SUNDAY NIGHT. THIS MAY BRING
ENOUGH MOISTURE AND LIFT ACROSS THE AREA TO PROVIDE A FOCUS FOR
ADDITIONAL SHOWERS TO OCCUR. THE GREATEST PROBABILITY MAY BE NORTH
OF OUR AREA, BUT WE KEEP A CHANCE OF SHOWERS THROUGH SUNDAY NIGHT.
WITH NOT MUCH INSTABILITY EXPECTED, THUNDER WAS LEFT OUT OF THE
FORECAST.
WE MAY THEN GET A DRYING OUT PERIOD AS WE GO INTO EARLY NEXT
WEEK. THERE MAY BE A FEW LINGERING SHOWERS EARLY MONDAY AS THE
AFOREMENTIONED LOW PULLS AWAY FROM THE AREA, BUT AFTER THAT, HIGH
PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TUESDAY INTO
WEDNESDAY.
TEMPERATURES THROUGH THE EXTENDED ARE EXPECTED TO BE A FEW
DEGREES ABOVE NORMAL, WITH THE WEEKEND BEING THE COOLEST WHICH MAY
END UP BEING VERY CLOSE TO NORMAL.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE STRING OF SPOTTY SHOWER ACTIVITY THIS MORNING WAS MAKING IT
DIFFICULT FOR SITES NORTH OF PHL TO CONSITENTLY RISE OUT OF THE
MVFR OR IFR RANGE. WE PRESENTLY ARE FORECASTING THAT ACTIVITY TO
DISSIPATE BY AROUND 16Z. CONFIDENCE IN THIS IS LOW TO MODERATE.
FROM PHL SOUTH, OUR FORECAST IS FOR VFR CONDITIONS FOR THE BALANCE
OF THE DAY. CONFIDENCE IN THIS IS MODERATE.
WEAK LOW PRESSURE APPROACHING FROM THE WEST IS FORECAST TO SPREAD
RAIN INTO OUR REGION FOR TONIGHT. CONDITIONS ARE EXPECTED TO LOWER
INTO THE MVFR CATEGORY AT MOST LOCATIONS. BRIEF PERIODS OF IFR ARE
POSSIBLE IN POCKETS OF MODERATE TO HEAVY RAIN, ESPECIALLY AT KRDG
AND KABE.
ANY THUNDERSTORM ACTIVITY FOR THIS AFTERNOON INTO TONIGHT SHOULD
BE VERY ISOLATED AND IT WILL NOT BE MENTIONED IN THE TAFS.
THE WIND IS FORECAST TO BE MOSTLY AT 8 KNOTS OR LESS FOR TODAY AT
VARYING DIRECTIONS. THE WIND SHOULD SETTLE INTO THE EAST TO SOUTH
QUADRANT FOR TONIGHT AT SPEEDS OF 10 KNOTS OR LESS.
OUTLOOK...
FRIDAY...PERIODS OF RAIN WITH MVFR/IFR CONDITIONS EXPECTED.
FRIDAY NIGHT-SATURDAY...CONDITIONS POSSIBLY IMPROVING TO
VFR...STILL A CHANCE OF MVFR CONDITIONS.
SATURDAY NIGHT-SUNDAY NIGHT...PERIODS OF RAIN WITH MVFR/IFR
CONDITIONS POSSIBLE.
MONDAY...CONDITIONS IMPROVING TO VFR.
&&
.MARINE...
A WEAK FRONTAL BOUNDARY FROM THE NORTHWEST WILL DROP INTO OUR
REGION FOR TODAY. WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM
THE WEST FOR TONIGHT. WIND SPEEDS AND WAVE HEIGHTS ARE ANTICIPATED
TO REMAIN BELOW THE SMALL CRAFT ADVISORY CRITERIA DURING TODAY AND
TONIGHT.
OUTLOOK...
THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN STALLED ACROSS THE
AREA THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. WINDS MAY
PERIODICALLY GUST AROUND 15-20 KNOTS. HOWEVER, WINDS AND WAVES ARE
EXPECTED TO REMAIN BELOW ADVISORY LEVELS. SEVERAL WAVES OF LOW
PRESSURE MAY DEVELOP ALONG THE BOUNDARY, WHICH WILL HAVE AN EFFECT
ON WIND DIRECTION.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ROBERTSON/DELISI
NEAR TERM...IOVINO/DELISI
SHORT TERM...IOVINO
LONG TERM...ROBERTSON
AVIATION...IOVINO/ROBERTSON/DELISI
MARINE...IOVINO/ROBERTSON
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
634 AM EDT THU SEP 27 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE TRAVELING ALONG A SLOW MOVING FRONTAL
BOUNDARY WILL BRING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS
TODAY. THE BOUNDARY WILL MOVE SOUTH OF THE OHIO RIVER TONIGHT
FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR FRIDAY. LOW PRESSURE
IN THE UPPER ATMOSPHERE WILL PROVIDE CLOUDS AND POSSIBLY A FEW
SHOWERS OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT IS SAGGING SLOWLY SOUTH THROUGH OHIO. A WAVE OF LOW
PRESSURE TRAVELING ALONG THE FRONT IS DEPICTED RATHER WELL ON THE
NAM AND RAP MODELS WHICH SHOW THE WAVE CROSSING THE ILN AREA
TODAY. THIS WILL BRING WIDESPREAD SHOWERS AND ISOLATED
THUNDERSTORMS FOR MOST OF THE FORECAST AREA...AND CURRENT RADAR
TRENDS SUPPORT THIS SCENARIO. WENT WITH CATEGORICAL POPS FOR MUCH
OF THE AREA...DECREASING TO CHANCE FROM WEST TO EAST DURING THE
AFTERNOON.
THE LACK OF INSTABILITY SHOULD KEEP ANY THUNDERSTORMS THAT FORM
BELOW SEVERE LIMITS. TEMPERATURES SHOULD TOP OUT AROUND 70 THIS
AFTERNOON...THOUGH THERE IS A GREAT DEAL OF UNCERTAINTY WITH
RESPECT TO TEMPERATURES DUE TO CLOUDS...PRECIPITATION...AND
FRONTAL POSITION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
MODELS NOW SHOW THE FRONT DROPPING FARTHER SOUTH THAN WAS
PREVIOUSLY INDICATED. THEREFORE...WENT WITH A DRY FORECAST FROM LATE
TONIGHT THROUGH FRIDAY NIGHT AS HIGH PRESSURE AND DRIER AIR WORK
IN FROM THE NORTH.
A DEEP CUT OFF UPPER LOW WILL BE MOVING SOUTH FROM CANADA TOWARD
THE ILN AREA ON SATURDAY. MOISTURE ASSOCIATED WITH THE SYSTEM SHOULD
STAY MAINLY TO THE NORTH...BUT CLOUDS WILL PROBABLY INCREASE AND
ISOLATED SHOWERS MAY AFFECT NORTHERN COUNTIES SATURDAY AFTERNOON.
HIGH TEMPERATURES ARE EXPECTED TO BE AROUND 70 BOTH FRIDAY AND
SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. FOR SUNDAY...FOCUSED
ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU. TIMING
OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT AND
ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR BOTH
SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON
TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD.
SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL
DAYTIME HIGHS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
IN SPLIT FLOW PATTERN S/W OVER SRN ILLINOIS TO RIPPLE EAST THRU
THE OHIO VALLEY THIS MORNING. NUMERICAL MODEL SOLNS IN BETTER
AGREEMENT WITH ASSOCIATED SFC LOW TRACKING EAST THRU SRN OHIO
ALONG A SLOW MOVING E-W ORIENTED SFC FRONTAL BOUNDARY. AREA OF
SHOWERS TO CONTINUE TO AFFECT THE TAF SITES THIS MORNING IN A
REGION OF FAVORABLE 925 MB CONVERGENCE. THEREFORE...WILL ALLOW FOR
A PERIOD OF SHOWERS THIS MORNING WITH CIGS/VSBYS DROPPING INTO
MVFR CATEGORY. WITH THE PASSAGE OF THIS SFC WAVE...THE FRONTAL
BOUNDARY WILL SINK SLOWLY SOUTH OF THE TAF SITES BY LATE AFTN.
EXPECT TO SEE CIGS IMPROVE THIS EVENING TO VFR BUT SOME BR
DEVELOPMENT WILL BE POSSIBLE. DEGREE AND TIMING FOR PARTIAL
CLEARING OVERNIGHT IS IN QUESTION ESPECIALLY ACRS THE SRN TAF
SITES CLOSER TO THE FRONTAL BOUNDARY. THEREFORE...HAVE LIMITED
VSBY RESTRICTIONS TO MVFR CATEGORY AT THIS TIME BUT WITH LIGHT
WINDS AND WET GROUND IFR VSBYS WILL BE POSSIBLE.
.OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...PADGETT
AVIATION...RANDALL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
946 AM CDT THU SEP 27 2012
.UPDATE...
RADAR IMAGERY THIS MORNING SHOWS AN AREA OF SHOWERS AND
THUNDERSTORMS EXTENDING FROM WESTERN KY TO JUST NORTH OF MEM
MOVING EASTWARD. LATEST HRRR RUNS SEEM TO HAVE A DECENT HANDLE ON
THIS ACTIVITY AND BRING IT ACROSS NORTHERN ZONES THROUGH THE REST
OF THE MORNING INTO THE AFTERNOON HOURS. ADDITIONAL BUT MORE
ISOLATED TO WIDELY SCATTERED SHOWERS AND MAYBE A STORM OR TWO
ALSO WILL LIKELY FORM TO THE SOUTH OF THIS ONGOING ACTIVITY AS
WELL. BASED ON THIS REASONING...HAVE KEPT THE INHERITED POPS
GENERALLY IN PLACE WITH SOME ADJUSTMENTS...SHOWING CATEGORICAL
POPS OVER THE NORTHWEST ZONES DIMINISHING TO SLIGHT/NO CHANCE
ALONG THE ALABAMA BORDER. CLOUD COVER ALSO ADJUSTED GENERALLY
UPWARD WHILE HIGH TEMPS WERE NUDGED DOWN OVER THE NORTHERN HALF.
REST OF FORECAST WAS LEFT UNCHANGED AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 708 AM CDT THU SEP 27 2012/
AVIATION 12Z DISCUSSION...
COLD FRONT TO THE NORTH OF TN THIS MORNING WILL MOVE SOUTHWARD AND
WILL BE LOCATED IN CLOSE PROXIMITY OF THE TAF AREAS ON FRIDAY
MORNING. ELEVATED INSTABILITY LEVELS WILL ALLOW FOR SOME ISOL TSTM
DEVELOPMENT THIS AFTERNOON. THEN AS THE FRONT SINKS SOUTHWARD...ISOL
TO SCT SHOWER ACTIVITY WILL CONTINUE OVERNIGHT. IFR CONDITIONS
WILL OCCUR BETWEEN 06Z AND 12Z AS CIGS AND VSBYS LOWER.
PREV DISCUSSION... /ISSUED 426 AM CDT THU SEP 27 2012/
DISCUSSION...
CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN
ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST
ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND
HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE
TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE
I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT
MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED
ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE
COLD FRONT BEGINS TO MOVE SOUTH.
THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND
INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS
INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE
INHIBITION.
THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND
SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY
SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO
THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S.
MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO
VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES
ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME
THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE
MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI
VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER
CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO
BE AROUND NORMAL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
708 AM CDT THU SEP 27 2012
.AVIATION 12Z DISCUSSION...
COLD FRONT TO THE NORTH OF TN THIS MORNING WILL MOVE SOUTHWARD AND
WILL BE LOCATED IN CLOSE PROXIMITY OF THE TAF AREAS ON FRIDAY
MORNING. ELEVATED INSTABILITY LEVELS WILL ALLOW FOR SOME ISOL TSTM
DEVELOPMENT THIS AFTERNOON. THEN AS THE FRONT SINKS SOUTHWARD...ISOL
TO SCT SHOWER ACTIVITY WILL CONTINUE OVERNIGHT. IFR CONDITIONS
WILL OCCUR BETWEEN 06Z AND 12Z AS CIGS AND VSBYS LOWER.
&&
.PREV DISCUSSION... /ISSUED 426 AM CDT THU SEP 27 2012/
DISCUSSION...
CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN
ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST
ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND
HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE
TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE
I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT
MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED
ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE
COLD FRONT BEGINS TO MOVE SOUTH.
THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND
INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS
INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE
INHIBITION.
THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND
SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY
SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO
THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S.
MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO
VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES
ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME
THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE
MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI
VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER
CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO
BE AROUND NORMAL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
622 AM CDT THU SEP 27 2012
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 231 AM CDT THU SEP 27 2012/
DISCUSSION...
A STALLED FRONT REMAINS LOCATED ACROSS SOUTHERN MISSOURI THIS
MORNING. SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG
THE BOUNDARY. LATEST HRRR MODEL INDICATES THESE SHOWERS AND
THUNDERSTORMS WILL BEGIN MOVING SOUTHEAST INTO THE CWA. LOOKING AT
LATEST RADAR IMAGES...BEGINNING TO SEE INDIVIDUAL STORMS MOVING TO
THE SOUTHEAST. AS A RESULT...WILL CONTINUE WITH LIKELY POPS ACROSS
NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND NORTHWEST
TENNESSEE INTO THE MORNING HOURS. HRRR SHOWS ACTIVITY DYING OUT
BY NOON TIME. DURING THE AFTERNOON...REDEVELOPMENT WILL LIKELY
OCCUR ACROSS SOUTHERN MISSOURI NEAR THE FRONT. SOME OF THE
ACTIVITY COULD SKIRT NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL
AND EXTREME NORTHWEST TENNESSEE. WILL GO WITH 40 POPS IN THE
AFTERNOON FOR THESE AREAS. ELSEWHERE...CONDITIONS SHOULD STAY DRY.
ALTHOUGH...MAY SEE MOSTLY CLOUDY CONDITIONS MAINLY FROM BLOW OFF
FROM CONVECTION OCCURRING TO THE NORTH OR WEST. HIGHS WILL BE IN
THE 80S.
TONIGHT...EXPECT WHATEVER ACTIVITY THAT DEVELOPS THIS AFTERNOON
ACROSS SOUTHERN MISSOURI TO BEGIN SPREADING SOUTHWARD INTO THE CWA
AS MODELS INDICATE FRONT MAY START MOVING TO THE SOUTH. BEST CHANCES
WILL OCCUR ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND
WEST TENNESSEE. LOWS WILL BE IN THE 60S.
FRIDAY AND FRIDAY NIGHT...FRONT PUSHES INTO THE CWA THUS EXPECT
CHANCES FOR SHOWERS AND THUNDERSTORMS TO SPREAD ACROSS THE ENTIRE
CWA. HOWEVER...EXPECT RAINFALL AMOUNTS TO REMAIN ON THE LIGHT SIDE.
THE WEEKEND...BY SATURDAY MORNING...COOLER AND DRIER AIR WILL BEGIN
SPREADING INTO PORTIONS OF NORTHWEST TENNESSEE. EXPECT FRONT TO
LIKELY BE LOCATED JUST TO THE SOUTH OF THE CWA. HOWEVER STILL EXPECT
SOME POST FRONTAL RAIN TO OCCUR MAINLY OVER NORTH MISSISSIPPI AND
EAST CENTRAL ARKANSAS. BY SATURDAY NIGHT INTO SUNDAY...EXPECT COOLER
AND DRIER AIR TO HAVE FILTERED INTO MUCH OF THE CWA WITH ONLY
EXTREME SOUTHERN PORTIONS OF THE CWA SEEING CONTINUING CHANCES FOR
RAIN.
MONDAY THROUGH WEDNESDAY...A BROAD UPPER TROF WILL REMAIN OVER THE
MIDSOUTH. MODELS KEEP FLIPPING BACK AND FORTH ON WHETHER A CLOSED
UPPER LOW FORMS. A SFC LOW IS EXPECTED TO DEVELOP ALONG THE GULF
COAST. DEPENDING ON THE LOCATION OF THE LOW...SOME RAIN COULD SPREAD
NORTHWARD INTO NORTHEAST MISSISSIPPI AS IT PUSHES EAST. FOR NOW WILL
CONTINUE WITH DRY FORECAST UNTIL MODELS SHOW SOME CONSISTENCY.
KRM
.AVIATION...
12Z TAFS
A VERY SLOW MOVING COLD FRONT WILL SINK SOUTH ACROSS THE MIDSOUTH
TODAY. WINDS WILL TURN NORTHERLY BEHIND THE FRONT REMAINING LESS
THAN 10 KNOTS THROUGHOUT THE TAF CYCLE. A FEW SHOWERS WILL BE
POSSIBLE...MAINLY BEFORE NOON TODAY AT JBR AND MKL...AND THEN
AGAIN AT JBR...MKL AND MEM OVERNIGHT. PRECIPITATION IS NOT
EXPECTED TO BE HEAVY ENOUGH TO REDUCE VISIBILITY
SIGNIFICANTLY....VFR CONDITIONS WILL PREVAIL.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 85 69 83 65 / 20 30 50 30
MKL 84 63 81 59 / 30 40 60 20
JBR 83 64 79 59 / 60 60 60 40
TUP 87 66 86 63 / 10 10 40 30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1023 AM EDT THU SEP 27 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY
SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL
TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED
STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EDT WEDNESDAY...
THE EARLY MORNING FORECAST PACKAGE APPEARS TO BE IN GOOD SHAPE...
WITH THE OBSERVED HOURLY TEMPERATURE INCREASES ON TRACK TO BE VERY
CLOSE TO EXPECTED AFTERNOON HIGHS. DID ADJUST THE AREA OF CLOUD
COVER IN THE FORECAST TO BETTER REFLECT LATEST VISIBLE SATELLITE
IMAGERY. STARTING TO SEE A FEW RETURNS ON RADAR OVER CENTRAL WEST
VIRGINIA...WHICH ARE EXPECTED TO APPROACH OUR WESTERN RIDGELINES
BY NOON...SO WILL CONTINUE TO MONITOR THE DEVELOPMENT OF THIS
ACTIVITY.
AS OF 420 AM EDT WEDNESDAY...
THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA.
MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE
ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE
FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS
OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT
LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION
INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z.
OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE
SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE
WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE
MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN
BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT.
TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING.
WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE
NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS
THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO
LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 340 AM EDT THURSDAY...
MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST
MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY
AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ.
MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO
SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA
DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND
EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE
ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE
VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING.
CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN
THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE
AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY
NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH
AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST.
RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES
COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL.
LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH
TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING
OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY
WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 245 PM EDT WEDNESDAY...
FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH
OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND
EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE
ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO
DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE
TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION.
THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY
NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH
THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL
APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK
THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE
GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL
TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN
EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE
OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH
SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 735 AM EDT THURSDAY...
PATCHY MORNING FOG WITH LIFR TO MVFR VISIBILITIES WILL MIX OUT BY
14Z/10AM. A COLD FRONT AND PERSISTENT BAROCLINIC ZONE TO THE
NORTH OF THE AREA WILL DRIFT INTO THE CWA DURING THE AFTERNOON.
LOCAL WRF MODELS PUT TIMING OF THE THUNDERSTORMS AFTER 20Z/4PM AT
BLF AND LWB. SO HAVE SLOWED DOWN ARRIVAL TIME OF PRECIPITATION IN
THE BLF/LWB/ROA AND BCB TAFS.
LOCATION OF THE SURFACE COLD FRONT WILL HAVE A BIG INFLUENCE ON
THE PROBABILITY OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA.
THE BEST PROBABILITY WILL BE TONIGHT THROUGH FRIDAY EVENING. MVFR
CEILINGS AND VISIBILITIES WILL BE POSSIBLE IN ANY OF THE STRONGER
STORMS ALONG WITH THE CHANCE FOR GUSTY WINDS.
AS THE FRONT DRIFTS SOUTH OF THE REGION SATURDAY THROUGH MONDAY
EXPECT DAYTIME VFR CONDITIONS. FOG WILL STILL BE LIKELY EACH NIGHT
IN THE FAVORED VALLEY LOCATIONS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...AMS/NF
SHORT TERM...RCS
LONG TERM...WP
AVIATION...AMS/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
743 AM EDT THU SEP 27 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY
SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL
TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED
STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 420 AM EDT WEDNESDAY...
THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA.
MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE
ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE
FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS
OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT
LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION
INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z.
OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE
SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE
WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE
MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN
BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT.
TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING.
WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE
NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS
THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO
LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 340 AM EDT THURSDAY...
MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST
MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY
AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ.
MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO
SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA
DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND
EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE
ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE
VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING.
CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN
THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE
AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY
NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH
AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST.
RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES
COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL.
LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH
TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING
OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY
WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 245 PM EDT WEDNESDAY...
FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH
OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND
EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE
ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO
DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE
TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION.
THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY
NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH
THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL
APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK
THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE
GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL
TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN
EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE
OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH
SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 735 AM EDT THURSDAY...
PATCHY MORNING FOG WITH LIFR TO MVFR VISIBILITIES WILL MIX OUT BY
14Z/10AM. A COLD FRONT AND PERSISTENT BAROCLINIC ZONE TO THE
NORTH OF THE AREA WILL DRIFT INTO THE CWA DURING THE AFTERNOON.
LOCAL WRF MODELS PUT TIMING OF THE THUNDERSTORMS AFTER 20Z/4PM AT
BLF AND LWB. SO HAVE SLOWED DOWN ARRIVAL TIME OF PRECIPITATION IN
THE BLF/LWB/ROA AND BCB TAFS.
LOCATION OF THE SURFACE COLD FRONT WILL HAVE A BIG INFLUENCE ON
THE PROBABILITY OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA.
THE BEST PROBABILITY WILL BE TONIGHT THROUGH FRIDAY EVENING. MVFR
CEILINGS AND VISIBILITIES WILL BE POSSIBLE IN ANY OF THE STRONGER
STORMS ALONG WITH THE CHANCE FOR GUSTY WINDS.
AS THE FRONT DRIFTS SOUTH OF THE REGION SATURDAY THROUGH MONDAY
EXPECT DAYTIME VFR CONDITIONS. FOG WILL STILL BE LIKELY EACH NIGHT
IN THE FAVORED VALLEY LOCATIONS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...AMS
SHORT TERM...RCS
LONG TERM...WP
AVIATION...AMS/RAB
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1037 AM MDT THU SEP 27 2012
.UPDATE...
&&
.SHORT TERM...UPPER LOW ESSSENTIALLY CUTOFF FROM THE MEAN FLOW
ALOFT CONTINUES TO TREK VERY SLOWLY EASTWARD ACROSS NORTHERN
COLORADO AT THIS HOUR. IR AND WATER VAPOR SAT IMAGERY INDICATE THE
CENTER OF THIS CYCLONE OVER KREMMLING IN WESTERN GRAND COUNTY IN
N/CNTRL COLORADO. RUC HT TENDENCY FIELDS INDICATED A SLIGHT
DEEPENING IN THIS LOW THIS MORNING...HOWEVER MODELS FORECAST A
GRADUAL INCREASE IN HEIGHTS AS THE 500MB LOW PASSES OVER NORTHEAST
COLORADO. MEANWHILE CIRCULATION AROUND THIS LOW CONTINUES TO PILE
LOW/MID- LEVEL CLOUDS UP THE WEST SIDE OF CONTINENTAL DIVIDE WHERE
SCATTERED LIGHT TO MODERATE SHOWERS HAVE BEEN OBSERVED. SNOW
LEVELS REMAIN HIGH THIS MORNING WITH THIS MORNING/S FREEZE LEVEL
UP AROUND 12,300 FT MSL. AS THE COLD AIR POOL ASSOCIATED WITH LOW
PASSES OVERHEAD...COULD SEE THE SNOW LEVEL LEVELING TO AROUND
10500-11000 FT MSL OVER THE NEXT SEVERAL HOURS.
NEXT ON PLAINS...LOW/MID-LEVEL CLOUDS WRAPPING NORTHWESTWARD BACK
INTO THE UPPER LOW AND THE SFC LOW IN SRN WELD COUNTY GENERATING
ISOLATED TO SCATTERED LIGHT RAIN SHOWERS ACROSS THE NORTHEAST
CORNER OF THE STATE FOR MOST OF THE MORNING. LIGHT DOWNSLOPE FLOW
OFF THE FRONT RANGE RESULTED IN SOME CLEARING OVER SOUTHERN
PORTIONS OFF THE I-25 CORRIDOR EARLIER THIS MORNING. ALTHOUGH IN
THE PAST HOUR WITH THE LITTLE SOLAR HEATING WE SAW AND NOW WITH
THE COOLING ALOFT...CLOUDS HAVE BEGUN TO FILL IN OVER THE ENTIRE
AREA. FURTHERMORE...A JETLET CURRENTLY ROUNDING THE BOTTOM OF THE
UPPER LOW WAS ALREADY HELPING TO ENHANCE CONVECTION/COOL CLOUD
TOPS OVER EL PASO...DOUGLAS AND LINCOLN COUNTIES. BASED ON CURRENT
TRENDS...SHOULD SEE THIS ENHANCEMENT SPREADING NORTHWARD OVER
EASTERN SECTIONS OF THE CWFA. AS IT APPEARS NOW...THE AREA MOST
LIKELY TO SEE THUNDERSTORMS TODAY...ROUGHLY AFTER 18Z WILL BE EAST
OF A BRIGGSDALE/WELD COUNTY TO KIOWA/ELBERT COUNTY LINE WHERE
CAPES ARE PROGGED TO BE IN THE 600-1200 J/KG RANGE LATER TODAY.
WEST OF THE LINE...CAN NOT RULE OUT A STRAY T-STORM BUT WITH LOW
LEVELS EXPECTED TO BEGIN DRYING LATER THIS AFTERNOON WITH
DOWNSLOPE FLOW DEVELOPING ON THE BACK SIDE OF THE UPPER LOW...THE
CHANCE FOR T-STORMS SHOULD DWINDLE TO NEAR ZERO TOWARDS 00Z. AS
FOR RAIN AMOUNTS...QPF FIELDS INDICATING 0.20 TO 0.45 INCH TOTALS
BY 03Z THIS EVENING ON THE PLAINS WITH THE HEAVIER AMOUNTS
ASSOCIATED WITH THE T-STORM ACTIVITY.
FOR THE HIGH COUNTRY...PARTICULARLY UP ALONG THE CONTINENTAL
DIVIDE ABOVE 11000 FT AND GENERALLY NORTH OF I-70...COULD SEE ANOTHER
FEW INCHES OF SNOW BEFORE WINDING DOWN THIS EVENING. OTHERWISE
TEMPERATURE FORECAST APPEARS TO BE ON TRACK. HOWEVER... OUR WIND
FCST WILL REMAIN A WORK IN PROGRESS THROUGHOUT THE DAY WITH THE
SFC AND UPPER LOWS PULLING AWAY.
.AVIATION...THE LOW AND MID-LEVEL CLOUD DECK MOVING SOUTHWARD
DOWN ALONG THE FRONT RANGE FOOTHILLS IS EXPECTED TO SPREAD OVER
THE DENVER AREA IN THE NEXT HOUR OR SO. ALREADY SEEING CEILINGS
AROUND 500 FT AGL AT BJC. PROBABLY IN THE NEXT HOUR COULD SEE
BROKEN CIGS AS LOW AS 1000-1500 FT AGL AT DENVER/S DIA AND APA
AIRPORTS. PATCHY FOG AROUND BJC MAY BRIEFLY LOWER VSBYS TO 3-5
MILES NEXT FEW HOURS. AFTER 18Z...THE CHANCE FOR RAIN SHOWERS
WILL INCREASE AS MOIST UPSLOPE FLOW DEVELOPS ON THE BACKSIDE OF
THE PASSING UPPER LOW. THE DENVER AREA MAY ALSO SEE A BRIEF
T-STORM THIS AFTERNOON...BUT THEIR INTENSITY SHOULD REMAIN ON THE
WEAK SIDE. AFTER 23Z OR 00Z THIS EVENING..THE DENVER AREA SHOULD
BEGIN TO SEE GRADUAL IMPROVEMENT AS DRIER AIR MOVES DOWN OFF THE
FRONT RANGE. HOWEVER LATE TONIGHT WITH CLEARING SKIES...PORTIONS
OFF THE DENVER AREA...INCLUDING DIA MAY SEE PATCHY FOG FORMING
TOWARDS DAWN.
&&
.HYDROLOGY...SHOWERS AND ISOLATED THUNDERSTORMS REMAIN IN THE
FORECAST FOR THE FRONT RANGE BURN SCARS TODAY. HOWEVER RAIN
AMOUNTS ARE EXPECTED TO REMAIN LIGHT...GENERALLY UNDER A QUARTER
INCH. THEREFORE FLOODING IS NOT ANTICIPATED.
&&
.PREV DISCUSSION... /ISSUED 405 AM MDT THU SEP 27 2012/
SHORT TERM...UPPER TROUGH IS ROTATING NORTHEASTWARD WITH A LOW
CENTER NEAR HAYDEN. THIS IS BRINGING SOME DRYING INTO OUR AREA FROM
THE SOUTH EARLY THIS MORNING...AND WHAT IS LEFT OF THE SHOWER
ACTIVITY IS NEARING THE EASTERN AND NORTHERN BORDER. CLOUDS ARE
STARTING TO FILL IN AGAIN FROM THE WEST THOUGH AS MOISTURE WRAPS
AROUND THE LOW. BETWEEN AN EASTWARD PROGRESSION OF THE LOW WITH THE
DRY SLOT FILLING AND THE DAYTIME HEATING...WE SHOULD HAVE PRETTY
GOOD COVERAGE OF SHOWERS AGAIN. IF THERE WERE MORE SUNSHINE WE COULD
GENERATE BETTER INSTABILITY...BUT THE COMBINATION OF SLIGHT DRYING
AND EARLY CLOUD COVER SHOULD KEEP A LID ON THINGS. MODEL SOUNDINGS
SHOW CAPES UP TO AROUND 1200 J/KG AT NOON...BUT THEN LESS LATER ON
DUE TO SOME LOW LEVEL DRYING/MIXING. IN ANY EVENT...SHOULD BE
ENOUGH CAPE FOR THUNDERSTORMS THIS AFTERNOON. OVERALL HEAVY RAIN
SHOULD BE A BIT LESS OF A THREAT WITH STORM MOTIONS AT LEAST 10
KNOTS...THOUGH TOWARD THE NORTHERN BORDER THE MOTIONS COULD BE
SLOWER AS THE LOW MOVES BY. THERE WILL STILL BE HEAVY RAIN IN THE
STRONGER THUNDERSTORM CORES...BUT ODDS OF REALLY SLOW MOVING STORMS
LOOK LOWER TODAY.
SO FEW CHANGES WITH THIS PACKAGE...MAINLY TO DRY THINGS OUT A LITTLE
THIS MORNING AND THEN ADD PATCHY FOG LATE TONIGHT.
LONG TERM...MODELS HAVE WEAK UPPER RIDGING MOVING INTO COLORADO
FRIDAY AND SATURDAY. THE FLOW ALOFT IS VERY WEAK AND MAINLY
WESTERLY FRIDAY INTO SATURDAY EVENING. THE SYNOPTIC SCALE ENERGY IS
PROGGED TO BE NEUTRAL OR WEAK DOWNWARD IN NATURE FRIDAY THROUGH
SATURDAY NIGHT. THE BOUNDARY LAYER FLOW WILL BE DICTATED BY A WEAK
LOW LEVEL PRESSURE GRADIENT THROUGH THE FOUR PERIODS...SO THE
NORMAL DIURNAL WIND PATTERNS ARE A GOOD BET. FOR MOISTURE...THERE
IS SOME AROUND ON FRIDAY INTO FRIDAY EVENING...ESPECIALLY ON THE
NAM. THE GFS AND ECMWF ARE DRIER. FRIDAY NIGHT DRIES OUT
SOMEWHAT. SATURDAY AND SATURDAY NIGHT ARE FAIRLY DRY...BUT THERE IS
STILL SOME MID AND UPPER LEVEL MOISTURE AROUND. PRECIPITABLE WATER
VALUES ARE GENERALLY IN THE 0.50 TO 0.65 INCH RANGE ALL FOUR
PERIODS. THERE IS SOME CAPE PROGGED FOR THE CWA FRIDAY AND SATURDAY
AFTERNOONS. VALUES ARE UNDER 800 J/KG...WITH MORE NOTED OVER THE
PLAINS...BUT STILL SOME IN THE MOUNTAINS. THE QPF FIELDS SHOW
LIMITED MEASURABLE PRECIPITATION MAINLY OVER THE MOUNTAINS AND
FOOTHILLS BOTH LATE DAY FRIDAY AND LATE DAY SATURDAY. FOR
POPS...20-30%S LATE DAY FRIDAY AND 10-20%S LATE DAY SATURDAY. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2.0-3.5 C WARMER THAN TODAY`S.
SATURDAY`S HIGHS WARM ANOTHER 1.0-2.5 C OVER FRIDAY`S. FOR THE
LATER DAYS...SUNDAY THROUGH WEDNESDAY...MODELS HAVE AN UPPER RIDGE
TO OUR WEST INTO WEDNESDAY. A WEAK UPPER TROUGH IS HINTED AT ON
WEDNESDAY...BUT IT IS INSIGNIFICANT. THE FLOW ALOFT WILL BE WEAK
AND NORTHERLY MONDAY AND TUESDAY...THEN NORTHWESTERLY AND WEAK
TUESDAY AND WEDNESDAY. MOISTURE IS POOR. TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
AVIATION...VFR CONDITIONS THIS MORNING. SCATTERED SHOWERS AND
THUNDERSTORMS MAY CAUSE LOCALIZED MVFR CONDITIONS THIS AFTERNOON AND
THERE WILL LIKELY BE A PERIOD WHEN INSTRUMENT APPROACHES TO KDEN ARE
NEEDED. CONVECTION ENDING THIS EVENING WITH A SLIGHT CHANCE OF IFR
CONDITIONS IN FOG LATE TONIGHT AND EARLY FRIDAY.
HYDROLOGY...LOW THREAT OF FLOODING TODAY AS SOME OF THE STORMS WILL
PRODUCE HEAVY RAIN. IN GENERAL STORMS WILL BE MOVING AT LEAST 10 MPH
WHICH WILL LIMIT THE FLOOD THREAT. HEAVIEST STORMS COULD PRODUCE AN
INCH OF RAIN IN AN HOUR...WITH UP TO 1.5 INCHES ON THE PLAINS...BUT
THESE RAINS WILL BE VERY LOCALIZED IF THEY OCCUR.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER/GIMMESTAD
LONG TERM....RJK
AVIATION...BAKER/GIMMESTAD
AREA FORECAST DISCUSSION
NWS NEW YORK NY
445 PM EDT THU SEP 27 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN JUST TO THE SOUTH THROUGH TONIGHT.
PRESSURE WILL MOVE SLOWLY EAST ALONG THE FRONT FROM THE OHIO
VALLEY TO SOUTHEAST PENNSYLVANIA BY FRIDAY MORNING...AND THEN
CROSS THE REGION FRIDAY AFTERNOON AND NIGHT. THE LOW WILL THEN
MOVE AWAY ON SATURDAY. ANOTHER WEAK LOW WILL PASS TO THE NORTHEAST
SUNDAY NIGHT INTO MONDAY. YET ANOTHER LOW WILL PASS TO THE
SOUTHEAST TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE
BUILDING IN FOR WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM COULD
AFFECT THE REGION AT THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SCT-BKN STRATOCU DEVELOPMENT THROUGH THIS AFTERNOON VIA
HEATING/MIXING. UPSTREAM MID CLOUDS ARE BEGINNING TO WORK IN AS
WELL FROM NYC WEST.
HIGH TEMPS IN THE MID 70S FOR MOST AREAS ON TRACK...WITH LOCALLY
UPPER 70S IN NYC/NJ METRO. AFTERNOON SEA BREEZE WILL KNOCK TEMPS
BACK INTO THE LOWER 70S THIS AFTERNOON ALONG COASTAL AREAS.
OVERRUNNING RAINS AHEAD OF THE WEAK SFC LOW WERE ENTERING SW PA AS
OF 18Z. LATEST HRRR INDICATES THIS RAIN SHOULD ENTER WRN SECTIONS
DURING THE LATE EVENING...THEN SPREAD EWD INTO THE REST OF THE CWA
AFTER MIDNIGHT. RAIN COULD BECOME HEAVY AT TIMES FROM NYC
NORTH/WEST TOWARD DAYBREAK. LOWS A BLEND OF MAV/MET
GUIDANCE...WITH 60-65 NYC METRO AND LONG ISLAND...AND 55-60
ELSEWHERE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
NWP GUIDANCE SUGGESTS HEAVIEST RAIN VIA BEST ISENTROPIC/OROGRAPHIC
LIFT AND FRONTOGENETIC FORCING WILL INITIALLY BE FOCUSED MORE JUST
TO THE NORTH/WEST OF THE CWA INTO FRI MORNING...BUT EVEN SO NYC
METRO AND THE LOWER HUDSON VALLEY SHOULD RECEIVE ABOUT AN INCH OF
RAIN THROUGH MIDDAY FRI.
AS THE WEAK LOW MOVES ACROSS FRI AFTERNOON...COMBO OF GOOD
MOISTURE TRANSPORT...ISENTROPIC LIFT AND INSTABILITY JUST TO ITS
EAST WITH MUCAPE INCREASING TO 500-1000 J/KG SHOULD BE ENOUGH TO
SUPPORT MODERATE TO LOCALLY HEAVY RAIN AND TSTMS. MOST MODELS ARE
UNDERPLAYING THIS...EXCEPT FOR THE 12Z RGEM WHICH IS A VERY WET
OUTLIER WITH UP TO 2 INCHES TOTAL QPF ACROSS SOUTHERN CT FRI
AFTERNOON. NYC METRO AND COASTAL SECTIONS MAY GET INTO THE WARM
SECTOR...WHERE INSTABILITY WILL BE SFC-BASED AND WHERE A FEW GUSTY
TSTMS ARE POSSIBLE.
THIS COMBO OF GOOD MOISTURE TRANSPORT...LIFT AND INSTABILITY
SHOULD LINGER ACROSS LONG ISLAND AND SOUTHERN CT INTO THE
EVENING...THEN WANE AFTER MIDNIGHT. A SECOND ROUND OF
SHOWERS/TSTMS MAY BE POSSIBLE FOR LONG ISLAND AND SOUTHERN CT
LATE FRI NIGHT AS A STRONG MID LEVEL VORT MAX AND POSSIBLE INDUCED
SFC WAVE SWEEP ACROSS OR JUST TO THE SE. MODELS DISAGREE ON
TIMING/PLACEMENT...SO HAVE JUST CONTINUED A GENERIC CHANCE POP
DURING THAT TIME.
THERE IS A HIGH RISK OF RIP CURRENTS AT THE OCEAN BEACHES WEDNESDAY.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
SOMEWHAT UNSETTLED..ALBEIT LIGHT PRECIPITATION IN THE LONG TERM AS
CUT OFF UPPER LEVEL LOW AND NEARLY STATIONARY COLD FRONT WELL OFF
THE EAST COAST ARE THE MAIN PLAYERS TO START OFF THE PERIOD. SURFACE
LOW PRESSURE ALONG THE STALLED FRONTAL BOUNDARY PUSHES AWAY FROM THE
AREA AS THE UPPER LEVEL LOW SITUATED BETWEEN THE HUDSON BAY AND THE
GREAT LAKES MOVES SOUTHWEST TOWARD THE GREAT LAKES ON SATURDAY. WITH
THE UPPER LOW IN THE VICINITY AND COLD POOL ALOFT...THERE WILL BE
SOME INSTABILITY SHOWERS ACROSS THE AREA...WITH THE BEST CHANCES
NORTH AND WEST OF THE NEW YORK METRO AREA.
A PIECE OF ENERGY FROM THE UPPER LEVEL LOW THEN SWINGS ACROSS THE
EASTERN GREAT LAKES AND TRACKS TO THE NORTHEAST SUNDAY INTO MONDAY.
THERE IS A GOOD DEAL OF UNCERTAINTY WITH THE TRACK OF THIS LOW. ALL
MODELS TRACK THIS LOW TO THE NORTH AND EAST OF THE AREA...BUT THE
ECMWF TRACKS THE LOW THROUGH CENTRAL NY...WHILE THE GFS TRACKS IT
ACROSS THE EASTERN GREAT LAKES...AND THE GEM IS CLOSER TO THE
ECMWF...BUT WEAKENS IT AS IT GETS ABSORBED INTO A COASTAL LOW. THE
ECMWF ALSO HAS THIS COASTAL LOW...BUT IT IS FARTHER OFFSHORE...MORE
ALIGNED WITH THE COLD FRONT...AND WEAKER. SO WENT WITH CHANCE POPS
DUE TO UNCERTAINTY.
HIGH PRESSURE BUILDS IN FOR MONDAY NIGHT. LOW PRESSURE FORMS ALONG
THE FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND TRACKS NORTHEAST
MONDAY. ECMWF AND GEM TRACKS THE LOW SOUTH AND EAST OF THE
CWA...WITH A SOLID HALF INCH OF QPF...WHILE THE GFS IS MORE
SUPPRESSED WITH HIGH PRESSURE OVER THE REGION FOR TUESDAY. HIGH
PRESSURE BUILDS IN FOR TUESDAY NIGHT AND WEDNESDAY...WITH POSSIBLY
ANOTHER SYSTEM POISED TO AFFECT THE REGION AT THE END OF THE WEEK.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT WILL REMAIN JUST TO THE SOUTH TODAY. A WAVE OF LOW
PRESSURE...ON THE FRONT...APPROACHES FROM THE WEST TONIGHT.
AS SEA BREEZE WINDS WEAKEN THIS EVENING WINDS WILL SHIFT TO THE
E/ESE AND INCREASE IN SPEED LATE TONIGHT INTO FRIDAY MORNING.
MODERATE CONFIDENCE IN 15-20 KT ESE WINDS LATE TONIGHT INTO FRIDAY
MORNING.
VFR THROUGH EARLY THIS EVENING...THEN CEILINGS GRADUALLY LOWER TO
MVFR LATE THIS EVENING. RAIN BECOMES INCREASINGLY LIKELY AFTER
MIDNIGHT TONIGHT. MODERATE CONFIDENCE IN IFR CONDITIONS IN WIND AND
RAIN AHEAD OF LOW PRESSURE TOWARDS DAYBREAK AND THROUGH FRIDAY
MORNING. ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS METRO AND
EASTERN TERMINALS...BUT TOO LOW PROBABILITY TO MENTION EXPLICITLY IN
TAFS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING
AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY
AROUND 12Z.
KJFK FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS
DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN
WIND AND RAIN BY AROUND 12Z.
KLGA FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING
AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY
AROUND 12Z.
KTEB FCSTER COMMENTS: SEA BREEZE MAY MOVE THROUGH AFTER
22Z...OTHERWISE WINDS REMAIN LIGHT AND VARIABLE. HIGH CONFIDENCE IN
MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN
IFR CONDS IN WIND AND RAIN BY AROUND 12Z.
KHPN FCSTER COMMENTS: WINDS LIKELY REMAIN LIGHT AND VARIABLE...LOW
CONFIDENCE IN SEA BREEZE MOVING THROUGH. HIGH CONFIDENCE IN MVFR
CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR
CONDS IN WIND AND RAIN BY AROUND 12Z.
KISP FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING
AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY
AROUND 12Z.
OUTLOOK FOR 18Z FRI-TUE...
.FRI...HIGH CONFIDENCE OF MVFR OR LOWER CONDITIONS IN RAIN.
.FRI NIGHT-TUE...GENERALLY VFR BUT MVFR OR LOWER CONDITIONS
POSSIBLE AT TIMES IN SHOWERS. LOW CONFIDENCE ON DETAILS.
&&
.MARINE...
SCA NOW IN EFFECT FOR ALL WATERS...BEGINNING ON THE OCEAN LATE
TONIGHT AND ON THE HARBOR/SOUND/BAYS BY FRI MORNING. EASTERLY FLOW
LOOKS TO INCREASE TO 15-20 WITH GUSTS UP TO 25 KT DURING THIS
TIME. OCEAN SEAS SHOULD MAX OUT AT EITHER 6-7 FT ON FRI...ABOUT 1
FT ABOVE 12Z WAVEWATCH.
SCA CONDS SHOULD LINGER ON THE ERN OCEAN WATERS UNTIL ABOUT
MIDNIGHT FRI NIGHT...THEN QUIET CONDITIONS ARE EXPECTED.
&&
.HYDROLOGY...
UP TO 2 INCHES OF RAINFALL POSSIBLE LATE TONIGHT THROUGH FRI
NIGHT. THE HEAVIEST RAIN WILL FALL MOSTLY NW OF THE LOW CENTER
INITIALLY LATE TONIGHT INTO FRI MORNING...FROM NYC METRO AND
POINTS NORTH/WEST...BUT THEN HEAVY RAIN FOCUS SHOULD SHIFT TO LONG
ISLAND AND SOUTHERN CT IN THE AFTERNOON JUST AHEAD OF THE LOW AS
IT MOVES ACROSS. MAIN CONCERN IS FOR MINOR FLOODING. ISOLD FLASH
FLOODING COULD OCCUR WITH HEAVIEST TSTMS FRI AFTERNOON AND EARLY
EVENING ACROSS LONG ISLAND AND SOUTHERN CT...BUT THIS THREAT
APPEARS TOO LOW/ISOLD TO WARRANT A WATCH. A STORM TOTAL GRAPHIC
HAS BEEN POSTED TO THE WEB.
&&
.TIDES/COASTAL FLOODING...
COMBO OF HIGH ASTRONOMICAL HIGH TIDES WITH THE UPCOMING FULL MOON
PLUS ABOUT 1 TO 1.5 FT OF SURGE AHEAD OF THE LOW APPROACHING
TONIGHT AND MOVING ACROSS ON FRI COULD LEAD TO ISOLATED MINOR
COASTAL FLOODING AT THE TIMES OF HIGH TIDE FRI NIGHT IN THE MOST
VULNERABLE LOCATIONS ALONG THE SOUTH SHORE BACK BAYS OF WRN LONG
ISLAND...AND ALONG WRN LONG ISLAND SOUND.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO NOON EDT FRIDAY FOR ANZ335-
338-345.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT FRIDAY FOR ANZ330-
340.
SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT FRIDAY FOR ANZ350-
353-355.
&&
$$
SYNOPSIS...
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...
AVIATION...MET
MARINE...GOODMAN
HYDROLOGY...GOODMAN
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
358 PM EDT THU SEP 27 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN JUST TO THE SOUTH THROUGH TONIGHT.
PRESSURE WILL MOVE SLOWLY EAST ALONG THE FRONT FROM THE OHIO
VALLEY TO SOUTHEAST PENNSYLVANIA BY FRIDAY MORNING...AND THEN
CROSS THE REGION FRIDAY AFTERNOON AND NIGHT. THE LOW WILL THEN
MOVE AWAY ON SATURDAY. ANOTHER WEAK LOW WILL PASS TO THE NORTHEAST
SUNDAY NIGHT INTO MONDAY. YET ANOTHER LOW WILL PASS TO THE
SOUTHEAST TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE
BUILDING IN FOR WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM COULD
AFFECT THE REGION AT THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCT-BKN STRATOCU DEVELOPMENT THROUGH THIS AFTERNOON VIA
HEATING/MIXING. UPSTREAM MID CLOUDS ARE BEGINNING TO WORK IN AS
WELL FROM NYC WEST.
HIGH TEMPS IN THE MID 70S FOR MOST AREAS ON TRACK...WITH LOCALLY
UPPER 70S IN NYC/NJ METRO. AFTERNOON SEA BREEZE WILL KNOCK TEMPS
BACK INTO THE LOWER 70S THIS AFTERNOON ALONG COASTAL AREAS.
OVERRUNNING RAINS AHEAD OF THE WEAK SFC LOW WERE ENTERING SW PA AS
OF 18Z. LATEST HRRR INDICATES THIS RAIN SHOULD ENTER WRN SECTIONS
DURING THE LATE EVENING...THEN SPREAD EWD INTO THE REST OF THE CWA
AFTER MIDNIGHT. RAIN COULD BECOME HEAVY AT TIMES FROM NYC
NORTH/WEST TOWARD DAYBREAK. LOWS A BLEND OF MAV/MET
GUIDANCE...WITH 60-65 NYC METRO AND LONG ISLAND...AND 55-60
ELSEWHERE.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
NWP GUIDANCE SUGGESTS HEAVIEST RAIN VIA BEST ISENTROPIC/OROGRAPHIC
LIFT AND FRONTOGENETIC FORCING WILL INITIALLY BE FOCUSED MORE JUST
TO THE NORTH/WEST OF THE CWA INTO FRI MORNING...BUT EVEN SO NYC
METRO AND THE LOWER HUDSON VALLEY SHOULD RECEIVE ABOUT AN INCH OF
RAIN THROUGH MIDDAY FRI.
AS THE WEAK LOW MOVES ACROSS FRI AFTERNOON...COMBO OF GOOD
MOISTURE TRANSPORT...ISENTROPIC LIFT AND INSTABILITY JUST TO ITS
EAST WITH MUCAPE INCREASING TO 500-1000 J/KG SHOULD BE ENOUGH TO
SUPPORT MODERATE TO LOCALLY HEAVY RAIN AND TSTMS. MOST MODELS ARE
UNDERPLAYING THIS...EXCEPT FOR THE 12Z RGEM WHICH IS A VERY WET
OUTLIER WITH UP TO 2 INCHES TOTAL QPF ACROSS SOUTHERN CT FRI
AFTERNOON. NYC METRO AND COASTAL SECTIONS MAY GET INTO THE WARM
SECTOR...WHERE INSTABILITY WILL BE SFC-BASED AND WHERE A FEW GUSTY
TSTMS ARE POSSIBLE.
THIS COMBO OF GOOD MOISTURE TRANSPORT...LIFT AND INSTABILITY
SHOULD LINGER ACROSS LONG ISLAND AND SOUTHERN CT INTO THE
EVENING...THEN WANE AFTER MIDNIGHT. A SECOND ROUND OF
SHOWERS/TSTMS MAY BE POSSIBLE FOR LONG ISLAND AND SOUTHERN CT
LATE FRI NIGHT AS A STRONG MID LEVEL VORT MAX AND POSSIBLE INDUCED
SFC WAVE SWEEP ACROSS OR JUST TO THE SE. MODELS DISAGREE ON
TIMING/PLACEMENT...SO HAVE JUST CONTINUED A GENERIC CHANCE POP
DURING THAT TIME.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SOMEWHAT UNSETTLED..ALBEIT LIGHT PRECIPITATION IN THE LONG TERM AS
CUT OFF UPPER LEVEL LOW AND NEARLY STATIONARY COLD FRONT WELL OFF
THE EAST COAST ARE THE MAIN PLAYERS TO START OFF THE PERIOD. SURFACE
LOW PRESSURE ALONG THE STALLED FRONTAL BOUNDARY PUSHES AWAY FROM THE
AREA AS THE UPPER LEVEL LOW SITUATED BETWEEN THE HUDSON BAY AND THE
GREAT LAKES MOVES SOUTHWEST TOWARD THE GREAT LAKES ON SATURDAY. WITH
THE UPPER LOW IN THE VICINITY AND COLD POOL ALOFT...THERE WILL BE
SOME INSTABILITY SHOWERS ACROSS THE AREA...WITH THE BEST CHANCES
NORTH AND WEST OF THE NEW YORK METRO AREA.
A PIECE OF ENERGY FROM THE UPPER LEVEL LOW THEN SWINGS ACROSS THE
EASTERN GREAT LAKES AND TRACKS TO THE NORTHEAST SUNDAY INTO MONDAY.
THERE IS A GOOD DEAL OF UNCERTAINTY WITH THE TRACK OF THIS LOW. ALL
MODELS TRACK THIS LOW TO THE NORTH AND EAST OF THE AREA...BUT THE
ECMWF TRACKS THE LOW THROUGH CENTRAL NY...WHILE THE GFS TRACKS IT
ACROSS THE EASTERN GREAT LAKES...AND THE GEM IS CLOSER TO THE
ECMWF...BUT WEAKENS IT AS IT GETS ABSORBED INTO A COASTAL LOW. THE
ECMWF ALSO HAS THIS COASTAL LOW...BUT IT IS FARTHER OFFSHORE...MORE
ALIGNED WITH THE COLD FRONT...AND WEAKER. SO WENT WITH CHANCE POPS
DUE TO UNCERTAINTY.
HIGH PRESSURE BUILDS IN FOR MONDAY NIGHT. LOW PRESSURE FORMS ALONG
THE FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND TRACKS NORTHEAST
MONDAY. ECMWF AND GEM TRACKS THE LOW SOUTH AND EAST OF THE
CWA...WITH A SOLID HALF INCH OF QPF...WHILE THE GFS IS MORE
SUPPRESSED WITH HIGH PRESSURE OVER THE REGION FOR TUESDAY. HIGH
PRESSURE BUILDS IN FOR TUESDAY NIGHT AND WEDNESDAY...WITH POSSIBLY
ANOTHER SYSTEM POISED TO AFFECT THE REGION AT THE END OF THE WEEK.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT WILL REMAIN JUST TO THE SOUTH TODAY. HIGH PRESSURE
WILL SLIDE ACROSS NEW ENGLAND THROUGH FRIDAY...WHILE LOW PRESSURE
APPROACHES FROM THE WEST TONIGHT.
WIND DIRECTION CONTINUES TO BE MAIN CHALLENGE THROUGH THIS
AFTERNOON. LIGHT NE TO VARIABLE WINDS WILL GRADUALLY VEER TO THE
EAST THROUGH THIS EVENING. BEFORE THEN...SEA BREEZE
DEVELOPMENT...EVIDENT ON TERMINAL RADAR...WILL BRING A WIND SHIFT
TO THE S/SE THIS AFTERNOON ACROSS MOST OF THE COASTAL TERMINALS.
HIGH CONFIDENCE IN WINDS DIRECTION BECOMING E/ESE THIS EVENING AND
INCREASING IN SPEED LATE TONIGHT INTO FRIDAY MORNING. MODERATE
CONFIDENCE IN 15-20 KT ESE WINDS LATE TONIGHT INTO FRIDAY MORNING.
GENERALLY VFR CONDITIONS THROUGH THE REMAINDER OF THE AFTERNOON...WITH
SCATTERED TO BROKEN CU ALONG WITH MID/HIGH CLOUDS REMAIN IN THE
FORECAST. CIGS ACROSS NW TERMINALS MAY OCCASIONALLY BE BROKEN
AROUND 3000FT THROUGH AROUND 22Z.
CEILINGS GRADUALLY LOWER TO MVFR LATE THIS EVENING WITH ONSHORE
FLOW. RAIN BECOMES INCREASINGLY LIKELY AFTER MIDNIGHT TONIGHT.
MODERATE CONFIDENCE IN IFR CONDITIONS IN WIND AND RAIN AHEAD OF LOW
PRESSURE TOWARDS DAYBREAK AND THROUGH FRIDAY MORNING. ISOLATED
THUNDERSTORMS ARE POSSIBLE ACROSS METRO AND EASTERN
TERMINALS...BUT TOO LOW PROBABILITY TO MENTION EXPLICITLY IN TAFS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE
TIMING...AROUND 19Z. HIGH CONFIDENCE IN MVFR CONDITIONS
DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN
WIND AND RAIN BY AROUND 12Z.
KJFK FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS
DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN
WIND AND RAIN BY AROUND 12Z.
KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE
TIMING...BETWEEN 20Z AND 21Z. HIGH CONFIDENCE IN MVFR CONDITIONS
DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN
WIND AND RAIN BY AROUND 12Z.
KTEB FCSTER COMMENTS: SEA BREEZE POSSIBLE BETWEEN 20Z AND 21Z. HIGH
CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE
CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z.
KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE
TIMING...AROUND 19Z. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING
AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN
BY AROUND 12Z.
KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE
TIMING...BETWEEN 19Z AND 20Z. HIGH CONFIDENCE IN MVFR CONDITIONS
DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN
WIND AND RAIN BY AROUND 12Z. ESE WINDS OF
OUTLOOK FOR 12Z FRI-TUE...
.FRI...HIGH CONFIDENCE OF MVFR OR LOWER CONDITIONS IN RAIN.
.FRI NIGHT-TUE...GENERALLY VFR BUT MVFR OR LOWER CONDITIONS
POSSIBLE AT TIMES IN SHOWERS. LOW CONFIDENCE ON DETAILS.
&&
.MARINE...
SCA NOW IN EFFECT FOR ALL WATERS...BEGINNING ON THE OCEAN LATE
TONIGHT AND ON THE HARBOR/SOUND/BAYS BY FRI MORNING. EASTERLY FLOW
LOOKS TO INCREASE TO 15-20 WITH GUSTS UP TO 25 KT DURING THIS
TIME. OCEAN SEAS SHOULD MAX OUT AT EITHER 6-7 FT ON FRI...ABOUT 1
FT ABOVE 12Z WAVEWATCH.
SCA CONDS SHOULD LINGER ON THE ERN OCEAN WATERS UNTIL ABOUT
MIDNIGHT FRI NIGHT...THEN QUIET CONDITIONS ARE EXPECTED.
&&
.HYDROLOGY...
UP TO 2 INCHES OF RAINFALL POSSIBLE LATE TONIGHT THROUGH FRI
NIGHT. THE HEAVIEST RAIN WILL FALL MOSTLY NW OF THE LOW CENTER
INITIALLY LATE TONIGHT INTO FRI MORNING...FROM NYC METRO AND
POINTS NORTH/WEST...BUT THEN HEAVY RAIN FOCUS SHOULD SHIFT TO LONG
ISLAND AND SOUTHERN CT IN THE AFTERNOON JUST AHEAD OF THE LOW AS
IT MOVES ACROSS. MAIN CONCERN IS FOR MINOR FLOODING. ISOLD FLASH
FLOODING COULD OCCUR WITH HEAVIEST TSTMS FRI AFTERNOON AND EARLY
EVENING ACROSS LONG ISLAND AND SOUTHERN CT...BUT THIS THREAT
APPEARS TOO LOW/ISOLD TO WARRANT A WATCH. A STORM TOTAL GRAPHIC
HAS BEEN POSTED TO THE WEB.
&&
.TIDES/COASTAL FLOODING...
COMBO OF HIGH ASTRONOMICAL HIGH TIDES WITH THE UPCOMING FULL MOON
PLUS ABOUT 1 TO 1.5 FT OF SURGE AHEAD OF THE LOW APPROACHING
TONIGHT AND MOVING ACROSS ON FRI COULD LEAD TO ISOLATED MINOR
COASTAL FLOODING AT THE TIMES OF HIGH TIDE FRI NIGHT IN THE MOST
VULNERABLE LOCATIONS ALONG THE SOUTH SHORE BACK BAYS OF WRN LONG
ISLAND...AND ALONG WRN LONG ISLAND SOUND.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO NOON EDT FRIDAY FOR ANZ335-
338-345.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT FRIDAY FOR ANZ330-
340.
SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT FRIDAY FOR ANZ350-
353-355.
&&
$$
SYNOPSIS...GOODMAN/JP
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...JP
AVIATION...NV
MARINE...GOODMAN/JP
HYDROLOGY...GOODMAN
TIDES/COASTAL FLOODING...GOODMAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
655 PM EDT THU SEP 27 2012
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 244 PM EDT THU SEP 27 2012
A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OF THE OHIO RIVER BY EARLY
FRIDAY AND BE REPLACED BY HIGH PRESSURE...BRINGING DRIER WEATHER AND
MORE SUNSHINE FOR FRIDAY. A SHARP UPPER LEVEL DISTURBANCE WILL DROP
THROUGH THE EASTERN GREAT LAKES OVER THE WEEKEND...USHERING IN A
COOLER AIRMASS BY SUNDAY. HIGH PRESSURE AND RIDGING ALOFT WILL
PROVIDE FOR DRY WEATHER WITH A WARMING TREND THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 244 PM EDT THU SEP 27 2012
BASED ON OBSERVATIONS AT 18Z...FRONTAL BOUNDARY APPEARS TO BE
LOCATED OVER FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. SKIES HAVE
SLOWLY CLEARED OVER THE NORTHERN HALF OF THE FORECAST AREA SO FAR
THIS AFTERNOON AS DRIER AIR NUDGES INTO THE REGION. HOWEVER AS
CONVECTIVE TEMPS ARE REACHED...AREAS ARE FILLING BACK IN WITH CU.
TEMPS WERE MAINLY IN THE 60S...ALTHOUGH A FEW LOCATIONS OVER THE
WABASH VALLEY HAD WARMED INTO THE 70S WHERE THE MOST SUNSHINE HAD
BEEN EXPERIENCED SO FAR.
THE FRONTAL BOUNDARY SHOULD CONTINUE A SLOW SOUTHWARD PROGRESSION
THROUGH THE REST OF THE AFTERNOON AND EVENING. WEAK VORT LOBES ALOFT
WILL CONTINUE TO TRAVERSE ALONG THE SURFACE BOUNDARY AND WARRANT AT
LEAST MAINTAINING A LOW CHANCE POPS ACROSS EXTREME SOUTHERN PORTIONS
OF THE FORECAST AREA THROUGH THE EVENING. HRRR ALSO CONTINUES TO
HINT AT WEAK AND WIDELY SCATTERED DEVELOPMENT IN THE VICINITY OF THE
BOUNDARY INTO THE EVENING. FURTHER NORTH...RAIN HAS ENDED WITH DRIER
AIR ADVECTING INTO THE REGION.
REVISITING POTENTIAL FOR LOW STRATUS AND FOG TO REDEVELOP LATER
TONIGHT AS DIURNAL CU THAT DEVELOPS THIS AFTERNOON DIMINISHES...AND
REMNANT CLOUD COVER AND MOISTURE EXPAND BACK NORTH. SOME UNCERTAINTY
WITH RESPECT TO COVERAGE OF BOTH STRATUS AND FOG...BUT CURRENT
THINKING AT THIS TIME IS THAT FOG MAY BE GREATER CONCERN OVER THE
NORTH AND WEST WHERE SKIES HAD CLEARED TO SOME DEGREE...WHILE POINTS
FURTHER SOUTH AND EAST LIKELY DEAL WITH LOW CLOUDS OVERNIGHT. MODEL
SOUNDINGS HINTING AT A SHALLOW INVERSION DEVELOPING AS WELL. HAVE
MAINTAINED MOSTLY CLOUDY SKIES FOR ALL BUT THE NORTHERN WABASH
VALLEY AND INSERTED PATCHY FOG FOR THE ENTIRE FORECAST AREA. COULD
CERTAINLY SEE LOCALIZED POCKETS OF DENSE FOG CONSIDERING AMOUNT OF
MOISTURE LEFTOVER ALONG WITH LIGHT WINDS.
TEMPS...TRENDED TOWARDS WARMER MAVMOS OVERNIGHT FOR LOWS...
ESPECIALLY WITH UNCERTAINTY REGARDING STRATUS COVERAGE AND FOG
POTENTIAL.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 244 PM EDT THU SEP 27 2012
FORECAST CHALLENGES FOCUS ON CLOUDS AND TEMPS AS A STRONG UPPER
LEVEL LOW DROPS SOUTH FROM JAMES BAY AND INTO THE EASTERN GREAT
LAKES OVER THE WEEKEND.
MODEL SOUNDINGS AND RH PROGS INDICATING SOME FORM OF STRATUS
REMAINING ACROSS PORTIONS OF THE FORECAST AREA WELL INTO THE
MORNING. PRESENCE OF A LOW LEVEL THERMAL TROUGH AND CONVECTIVE TEMPS
IN THE 60S SHOULD ENSURE THAT THE LEFTOVER STRATUS WILL MIX OUT INTO
A FAIRLY WELL DEVELOPED CU FIELD FOR THE AFTERNOON AND WILL ROLL
WITH PARTLY CLOUDY SKIES.
SKIES WILL CLEAR FRIDAY EVENING WITH HIGH PRESSURE ACROSS THE
REGION...BUT ANTICIPATE SOME MID LEVEL CLOUDS EXPANDING BACK ACROSS
CENTRAL INDIANA LATE FRIDAY NIGHT AND INTO SATURDAY MORNING AS A
SHORTWAVE ALOFT PASSES THROUGH. THE PASSAGE OF THE SHORTWAVE WILL
SIGNAL THE BEGINNING OF A DEEPENING AND SOUTHWARD TREK TO AN UPPER
LOW SOUTH FROM JAMES BAY. THE UPPER LOW WILL DIVE THROUGH THE
EASTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY AND SERVE TO SHARPEN
THE UPPER LEVEL TROUGHING AND CYCLONIC FLOW ALOFT OVER MUCH OF THE
OHIO VALLEY. WHILE CENTRAL INDIANA WILL NOT BE DIRECTLY IMPACTED
FROM THE UPPER LOW WITH THE MORE SIGNIFICANT FORCING ALOFT REMAINING
TO THE NORTHEAST...THE RELATIVE PROXIMITY OF THE UPPER LOW WILL
BRING A RENEWED SURGE OF COOLER AIR AND SOME CLOUDS THROUGH MIDDAY
SUNDAY. SKIES WILL CLEAR BY LATE DAY SUNDAY AS THE FEATURE PULLS
AWAY TO THE EAST AND HIGH PRESSURE REASSERTS A STRONGER INFLUENCE
OVER THE REGION.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE FOR TEMPERATURES FRIDAY
THROUGH SUNDAY CONSIDERING 850MB TEMPS AND LOW LEVEL THERMAL
TECHNIQUES. COOLEST DAY SHOULD BE SUNDAY AS PRESENCE OF LOW LEVEL
COLD ADVECTION ON THE BACK SIDE OF THE UPPER LOW WILL KEEP MUCH OF
THE FORECAST AREA IN THE 60S. LEANED TOWARDS METMOS FOR LOWS AS IT
APPEARS TO CAPTURE THE VARIANCE IN TEMPS IN RURAL AREAS BETTER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 227 PM EDT THU SEP 27 2012
LONG TERM PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE AND
ZONAL TO WEAKLY CYCLONIC FLOW.
ONLY REAL OPPORTUNITY FOR PRECIPITATION APPEARS TO BE VERY LATE IN
THE PERIOD AS MODELS BRING A SLUG OF TROPICAL MOISTURE NORTH FROM
THE GULF COAST LATE IN THE WEEK. IT IS ONLY IN THE AREA BRIEFLY
BEFORE BEING QUICKLY PULLED NORTHEAST. LOW POPS PROVIDED BY
ALLBLEND APPEARED REASONABLE AND DID NOT CHANGE SIGNIFICANTLY.
TEMPERATURES FROM INITIALIZATION APPEARED SLIGHTLY COOL BASED ON
850 TEMPS FROM GFS/EURO. RAISED HIGHS A DEGREE ACROSS THE BOARD.
LOWS LOOKED FINE.
&&
.AVIATION /DISCUSSION FOR THE 280000Z TAF ISSUANCE/...
ISSUED AT 655 PM EDT THU SEP 27 2012
IFR CONDITIONS LIKELY AGAIN LATE TONIGHT AND EARLY FRIDAY. HIGH
PRESSURE BUILDING INTO THE GREAT LAKES WAS PRODUCING A VERY LIGHT
NORTH TO NORTHEAST FLOW. DRIER AIR WAS POISED TO OUR NORTHWEST. BUT
DEWPOINTS WERE STILL IN THE UPPER 50S TO MIDDLE 60S ACROSS CENTRAL
INDIANA. WITH VERY LIGHT WINDS AND A MOIST GROUND DO NOT EXPECT
DEWPOINTS TO DROP ENOUGH TO PRECLUDE STRATUS/FOG. ONE POSSIBLE
EXCEPTION MIGHT BE KLAF...SO WILL BE SLIGHTLY MORE OPTIMISTIC THERE.
KBMG ON OTHER HAND MAY DROP TO LIFR CONDITIONS OVERNIGHT.
ON FRIDAY...STRATUS/FOG WILL LIFT BY MID TO LATE MORNING. CONVECTIVE
TEMPERATURES WILL BE IN UPPER 60S...SO EXPECT MOSTLY BROKEN 4 TO 5
THOUSAND CLOUDS MIDDAY ON WITH SOME CLEARING TOWARDS END OF THE TAF
PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....NIELD
AVIATION...JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
428 PM EDT THU SEP 27 2012
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 244 PM EDT THU SEP 27 2012
A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OF THE OHIO RIVER BY EARLY
FRIDAY AND BE REPLACED BY HIGH PRESSURE...BRINGING DRIER WEATHER AND
MORE SUNSHINE FOR FRIDAY. A SHARP UPPER LEVEL DISTURBANCE WILL DROP
THROUGH THE EASTERN GREAT LAKES OVER THE WEEKEND...USHERING IN A
COOLER AIRMASS BY SUNDAY. HIGH PRESSURE AND RIDGING ALOFT WILL
PROVIDE FOR DRY WEATHER WITH A WARMING TREND THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 244 PM EDT THU SEP 27 2012
BASED ON OBSERVATIONS AT 18Z...FRONTAL BOUNDARY APPEARS TO BE
LOCATED OVER FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. SKIES HAVE
SLOWLY CLEARED OVER THE NORTHERN HALF OF THE FORECAST AREA SO FAR
THIS AFTERNOON AS DRIER AIR NUDGES INTO THE REGION. HOWEVER AS
CONVECTIVE TEMPS ARE REACHED...AREAS ARE FILLING BACK IN WITH CU.
TEMPS WERE MAINLY IN THE 60S...ALTHOUGH A FEW LOCATIONS OVER THE
WABASH VALLEY HAD WARMED INTO THE 70S WHERE THE MOST SUNSHINE HAD
BEEN EXPERIENCED SO FAR.
THE FRONTAL BOUNDARY SHOULD CONTINUE A SLOW SOUTHWARD PROGRESSION
THROUGH THE REST OF THE AFTERNOON AND EVENING. WEAK VORT LOBES ALOFT
WILL CONTINUE TO TRAVERSE ALONG THE SURFACE BOUNDARY AND WARRANT AT
LEAST MAINTAINING A LOW CHANCE POPS ACROSS EXTREME SOUTHERN PORTIONS
OF THE FORECAST AREA THROUGH THE EVENING. HRRR ALSO CONTINUES TO
HINT AT WEAK AND WIDELY SCATTERED DEVELOPMENT IN THE VICINITY OF THE
BOUNDARY INTO THE EVENING. FURTHER NORTH...RAIN HAS ENDED WITH DRIER
AIR ADVECTING INTO THE REGION.
REVISITING POTENTIAL FOR LOW STRATUS AND FOG TO REDEVELOP LATER
TONIGHT AS DIURNAL CU THAT DEVELOPS THIS AFTERNOON DIMINISHES...AND
REMNANT CLOUD COVER AND MOISTURE EXPAND BACK NORTH. SOME UNCERTAINTY
WITH RESPECT TO COVERAGE OF BOTH STRATUS AND FOG...BUT CURRENT
THINKING AT THIS TIME IS THAT FOG MAY BE GREATER CONCERN OVER THE
NORTH AND WEST WHERE SKIES HAD CLEARED TO SOME DEGREE...WHILE POINTS
FURTHER SOUTH AND EAST LIKELY DEAL WITH LOW CLOUDS OVERNIGHT. MODEL
SOUNDINGS HINTING AT A SHALLOW INVERSION DEVELOPING AS WELL. HAVE
MAINTAINED MOSTLY CLOUDY SKIES FOR ALL BUT THE NORTHERN WABASH
VALLEY AND INSERTED PATCHY FOG FOR THE ENTIRE FORECAST AREA. COULD
CERTAINLY SEE LOCALIZED POCKETS OF DENSE FOG CONSIDERING AMOUNT OF
MOISTURE LEFTOVER ALONG WITH LIGHT WINDS.
TEMPS...TRENDED TOWARDS WARMER MAVMOS OVERNIGHT FOR LOWS...
ESPECIALLY WITH UNCERTAINTY REGARDING STRATUS COVERAGE AND FOG
POTENTIAL.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 244 PM EDT THU SEP 27 2012
FORECAST CHALLENGES FOCUS ON CLOUDS AND TEMPS AS A STRONG UPPER
LEVEL LOW DROPS SOUTH FROM JAMES BAY AND INTO THE EASTERN GREAT
LAKES OVER THE WEEKEND.
MODEL SOUNDINGS AND RH PROGS INDICATING SOME FORM OF STRATUS
REMAINING ACROSS PORTIONS OF THE FORECAST AREA WELL INTO THE
MORNING. PRESENCE OF A LOW LEVEL THERMAL TROUGH AND CONVECTIVE TEMPS
IN THE 60S SHOULD ENSURE THAT THE LEFTOVER STRATUS WILL MIX OUT INTO
A FAIRLY WELL DEVELOPED CU FIELD FOR THE AFTERNOON AND WILL ROLL
WITH PARTLY CLOUDY SKIES.
SKIES WILL CLEAR FRIDAY EVENING WITH HIGH PRESSURE ACROSS THE
REGION...BUT ANTICIPATE SOME MID LEVEL CLOUDS EXPANDING BACK ACROSS
CENTRAL INDIANA LATE FRIDAY NIGHT AND INTO SATURDAY MORNING AS A
SHORTWAVE ALOFT PASSES THROUGH. THE PASSAGE OF THE SHORTWAVE WILL
SIGNAL THE BEGINNING OF A DEEPENING AND SOUTHWARD TREK TO AN UPPER
LOW SOUTH FROM JAMES BAY. THE UPPER LOW WILL DIVE THROUGH THE
EASTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY AND SERVE TO SHARPEN
THE UPPER LEVEL TROUGHING AND CYCLONIC FLOW ALOFT OVER MUCH OF THE
OHIO VALLEY. WHILE CENTRAL INDIANA WILL NOT BE DIRECTLY IMPACTED
FROM THE UPPER LOW WITH THE MORE SIGNIFICANT FORCING ALOFT REMAINING
TO THE NORTHEAST...THE RELATIVE PROXIMITY OF THE UPPER LOW WILL
BRING A RENEWED SURGE OF COOLER AIR AND SOME CLOUDS THROUGH MIDDAY
SUNDAY. SKIES WILL CLEAR BY LATE DAY SUNDAY AS THE FEATURE PULLS
AWAY TO THE EAST AND HIGH PRESSURE REASSERTS A STRONGER INFLUENCE
OVER THE REGION.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE FOR TEMPERATURES FRIDAY
THROUGH SUNDAY CONSIDERING 850MB TEMPS AND LOW LEVEL THERMAL
TECHNIQUES. COOLEST DAY SHOULD BE SUNDAY AS PRESENCE OF LOW LEVEL
COLD ADVECTION ON THE BACK SIDE OF THE UPPER LOW WILL KEEP MUCH OF
THE FORECAST AREA IN THE 60S. LEANED TOWARDS METMOS FOR LOWS AS IT
APPEARS TO CAPTURE THE VARIANCE IN TEMPS IN RURAL AREAS BETTER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 227 PM EDT THU SEP 27 2012
LONG TERM PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE AND
ZONAL TO WEAKLY CYCLONIC FLOW.
ONLY REAL OPPORTUNITY FOR PRECIPITATION APPEARS TO BE VERY LATE IN
THE PERIOD AS MODELS BRING A SLUG OF TROPICAL MOISTURE NORTH FROM
THE GULF COAST LATE IN THE WEEK. IT IS ONLY IN THE AREA BRIEFLY
BEFORE BEING QUICKLY PULLED NORTHEAST. LOW POPS PROVIDED BY
ALLBLEND APPEARED REASONABLE AND DID NOT CHANGE SIGNIFICANTLY.
TEMPERATURES FROM INITIALIZATION APPEARED SLIGHTLY COOL BASED ON
850 TEMPS FROM GFS/EURO. RAISED HIGHS A DEGREE ACROSS THE BOARD.
LOWS LOOKED FINE.
&&
.AVIATION /DISCUSSION FOR THE 27/21Z KIND TAF UPDATE/...
ISSUED AT 428 PM EDT THU SEP 27 2012
MINOR TWEAKS MADE TO KIND TAF PER OBSERVATIONS. NO OTHER CHANGES
NEEDED AT THIS TIME. PREVIOUS AVIATION DISCUSSION FOLLOWS...
RESTRICTIONS LIKELY FOR A SIGNIFICANT PORTION OF THE TAF PERIOD AT
MOST SITES.
IFR SHOULD CONTINUE INTO MID AFTERNOON AT IND/BMG...WITH CONDITIONS
HAVING QUICKLY IMPROVED AT LAF/BMG EARLY THIS AFTERNOON. APPEARS
FROM FORECAST SOUNDINGS THAT LOW CLOUD WILL LIFT AND SCOUR OUT EARLY
THIS EVENING WITH ONLY SOME MID CLOUD IN THE AREA...BUT
OVERNIGHT...EXPECT THAT COOLING AIR AND REMAINING LOW LEVEL MOISTURE
WILL COMBINE TO ONCE AGAIN BRING IFR CONDITIONS TO THE
SITES...PERHAPS EVEN LIFR OR WORSE. FOR NOW...WILL INCLUDE 1-3SM BR
AND BKN005-007 AFTER 04-08Z.
WINDS WILL BE BELOW 10KT THROUGH THE PERIOD...VARIABLE AT TIMES BUT
GENERALLY OUT OF THE NORTH NORTHEAST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....NIELD
AVIATION...NIELD/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
244 PM EDT THU SEP 27 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 244 PM EDT THU SEP 27 2012
A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OF THE OHIO RIVER BY EARLY
FRIDAY AND BE REPLACED BY HIGH PRESSURE...BRINGING DRIER WEATHER AND
MORE SUNSHINE FOR FRIDAY. A SHARP UPPER LEVEL DISTURBANCE WILL DROP
THROUGH THE EASTERN GREAT LAKES OVER THE WEEKEND...USHERING IN A
COOLER AIRMASS BY SUNDAY. HIGH PRESSURE AND RIDGING ALOFT WILL
PROVIDE FOR DRY WEATHER WITH A WARMING TREND THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 244 PM EDT THU SEP 27 2012
BASED ON OBSERVATIONS AT 18Z...FRONTAL BOUNDARY APPEARS TO BE
LOCATED OVER FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. SKIES HAVE
SLOWLY CLEARED OVER THE NORTHERN HALF OF THE FORECAST AREA SO FAR
THIS AFTERNOON AS DRIER AIR NUDGES INTO THE REGION. HOWEVER AS
CONVECTIVE TEMPS ARE REACHED...AREAS ARE FILLING BACK IN WITH CU.
TEMPS WERE MAINLY IN THE 60S...ALTHOUGH A FEW LOCATIONS OVER THE
WABASH VALLEY HAD WARMED INTO THE 70S WHERE THE MOST SUNSHINE HAD
BEEN EXPERIENCED SO FAR.
THE FRONTAL BOUNDARY SHOULD CONTINUE A SLOW SOUTHWARD PROGRESSION
THROUGH THE REST OF THE AFTERNOON AND EVENING. WEAK VORT LOBES ALOFT
WILL CONTINUE TO TRAVERSE ALONG THE SURFACE BOUNDARY AND WARRANT AT
LEAST MAINTAINING A LOW CHANCE POPS ACROSS EXTREME SOUTHERN PORTIONS
OF THE FORECAST AREA THROUGH THE EVENING. HRRR ALSO CONTINUES TO
HINT AT WEAK AND WIDELY SCATTERED DEVELOPMENT IN THE VICINITY OF THE
BOUNDARY INTO THE EVENING. FURTHER NORTH...RAIN HAS ENDED WITH DRIER
AIR ADVECTING INTO THE REGION.
REVISITING POTENTIAL FOR LOW STRATUS AND FOG TO REDEVELOP LATER
TONIGHT AS DIURNAL CU THAT DEVELOPS THIS AFTERNOON DIMINISHES...AND
REMNANT CLOUD COVER AND MOISTURE EXPAND BACK NORTH. SOME UNCERTAINTY
WITH RESPECT TO COVERAGE OF BOTH STRATUS AND FOG...BUT CURRENT
THINKING AT THIS TIME IS THAT FOG MAY BE GREATER CONCERN OVER THE
NORTH AND WEST WHERE SKIES HAD CLEARED TO SOME DEGREE...WHILE POINTS
FURTHER SOUTH AND EAST LIKELY DEAL WITH LOW CLOUDS OVERNIGHT. MODEL
SOUNDINGS HINTING AT A SHALLOW INVERSION DEVELOPING AS WELL. HAVE
MAINTAINED MOSTLY CLOUDY SKIES FOR ALL BUT THE NORTHERN WABASH
VALLEY AND INSERTED PATCHY FOG FOR THE ENTIRE FORECAST AREA. COULD
CERTAINLY SEE LOCALIZED POCKETS OF DENSE FOG CONSIDERING AMOUNT OF
MOISTURE LEFTOVER ALONG WITH LIGHT WINDS.
TEMPS...TRENDED TOWARDS WARMER MAVMOS OVERNIGHT FOR LOWS...
ESPECIALLY WITH UNCERTAINTY REGARDING STRATUS COVERAGE AND FOG
POTENTIAL.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 244 PM EDT THU SEP 27 2012
FORECAST CHALLENGES FOCUS ON CLOUDS AND TEMPS AS A STRONG UPPER
LEVEL LOW DROPS SOUTH FROM JAMES BAY AND INTO THE EASTERN GREAT
LAKES OVER THE WEEKEND.
MODEL SOUNDINGS AND RH PROGS INDICATING SOME FORM OF STRATUS
REMAINING ACROSS PORTIONS OF THE FORECAST AREA WELL INTO THE
MORNING. PRESENCE OF A LOW LEVEL THERMAL TROUGH AND CONVECTIVE TEMPS
IN THE 60S SHOULD ENSURE THAT THE LEFTOVER STRATUS WILL MIX OUT INTO
A FAIRLY WELL DEVELOPED CU FIELD FOR THE AFTERNOON AND WILL ROLL
WITH PARTLY CLOUDY SKIES.
SKIES WILL CLEAR FRIDAY EVENING WITH HIGH PRESSURE ACROSS THE
REGION...BUT ANTICIPATE SOME MID LEVEL CLOUDS EXPANDING BACK ACROSS
CENTRAL INDIANA LATE FRIDAY NIGHT AND INTO SATURDAY MORNING AS A
SHORTWAVE ALOFT PASSES THROUGH. THE PASSAGE OF THE SHORTWAVE WILL
SIGNAL THE BEGINNING OF A DEEPENING AND SOUTHWARD TREK TO AN UPPER
LOW SOUTH FROM JAMES BAY. THE UPPER LOW WILL DIVE THROUGH THE
EASTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY AND SERVE TO SHARPEN
THE UPPER LEVEL TROUGHING AND CYCLONIC FLOW ALOFT OVER MUCH OF THE
OHIO VALLEY. WHILE CENTRAL INDIANA WILL NOT BE DIRECTLY IMPACTED
FROM THE UPPER LOW WITH THE MORE SIGNIFICANT FORCING ALOFT REMAINING
TO THE NORTHEAST...THE RELATIVE PROXIMITY OF THE UPPER LOW WILL
BRING A RENEWED SURGE OF COOLER AIR AND SOME CLOUDS THROUGH MIDDAY
SUNDAY. SKIES WILL CLEAR BY LATE DAY SUNDAY AS THE FEATURE PULLS
AWAY TO THE EAST AND HIGH PRESSURE REASSERTS A STRONGER INFLUENCE
OVER THE REGION.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE FOR TEMPERATURES FRIDAY
THROUGH SUNDAY CONSIDERING 850MB TEMPS AND LOW LEVEL THERMAL
TECHNIQUES. COOLEST DAY SHOULD BE SUNDAY AS PRESENCE OF LOW LEVEL
COLD ADVECTION ON THE BACK SIDE OF THE UPPER LOW WILL KEEP MUCH OF
THE FORECAST AREA IN THE 60S. LEANED TOWARDS METMOS FOR LOWS AS IT
APPEARS TO CAPTURE THE VARIANCE IN TEMPS IN RURAL AREAS BETTER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 227 PM EDT THU SEP 27 2012
LONG TERM PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE AND
ZONAL TO WEAKLY CYCLONIC FLOW.
ONLY REAL OPPORTUNITY FOR PRECIPITATION APPEARS TO BE VERY LATE IN
THE PERIOD AS MODELS BRING A SLUG OF TROPICAL MOISTURE NORTH FROM
THE GULF COAST LATE IN THE WEEK. IT IS ONLY IN THE AREA BRIEFLY
BEFORE BEING QUICKLY PULLED NORTHEAST. LOW POPS PROVIDED BY
ALLBLEND APPEARED REASONABLE AND DID NOT CHANGE SIGNIFICANTLY.
TEMPERATURES FROM INITIALIZATION APPEARED SLIGHTLY COOL BASED ON
850 TEMPS FROM GFS/EURO. RAISED HIGHS A DEGREE ACROSS THE BOARD.
LOWS LOOKED FINE.
&&
.AVIATION /DISCUSSION FOR THE 27/18Z TAFS/...
ISSUED AT 116 PM EDT THU SEP 27 2012
RESTRICTIONS LIKELY FOR A SIGNIFICANT PORTION OF THE TAF PERIOD AT
MOST SITES.
IFR SHOULD CONTINUE INTO MID AFTERNOON AT IND/BMG...WITH CONDITIONS
HAVING QUICKLY IMPROVED AT LAF/BMG EARLY THIS AFTERNOON. APPEARS
FROM FORECAST SOUNDINGS THAT LOW CLOUD WILL LIFT AND SCOUR OUT EARLY
THIS EVENING WITH ONLY SOME MID CLOUD IN THE AREA...BUT
OVERNIGHT...EXPECT THAT COOLING AIR AND REMAINING LOW LEVEL MOISTURE
WILL COMBINE TO ONCE AGAIN BRING IFR CONDITIONS TO THE
SITES...PERHAPS EVEN LIFR OR WORSE. FOR NOW...WILL INCLUDE 1-3SM BR
AND BKN005-007 AFTER 04-08Z.
WINDS WILL BE BELOW 10KT THROUGH THE PERIOD...VARIABLE AT TIMES BUT
GENERALLY OUT OF THE NORTH NORTHEAST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....NIELD
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
128 PM EDT THU SEP 27 2012
.AVIATION...
NORTHEASTERLY FLOW OFF THE GREAT LAKES IS HELPING TO MAINTAIN A
FAIR AMOUNT OF LOW LEVEL MOISTURE BEHIND THE EXITING FRONTAL
BOUNDARY. THIS WILL LEAD TO LOW END VFR CONDITIONS FOR THE REST OF
THE DAY. LATEST FORECAST SOUNDINGS SUGGEST THIS MOISTURE WILL
REMAIN IN PLACE THROUGH TOMORROW. LEFT CEILINGS IN VFR CATEGORY
FOR NOW BUT MVFR CONDITIONS ARE POSSIBLE OVERNIGHT WITH LIGHT
NORTHEASTERLY WINDS.
&&
.PREV DISCUSSION... /ISSUED 503 AM EDT THU SEP 27 2012/
SHORT TERM...
TODAY THROUGH FRIDAY NIGHT.
PRIMARY CONCERN WRT OH VLY FRONTAL WAVE STRENGTH/POSITIONING AND
POTNL FOR SHRA TO SKIRT FAR SERN CWA LATER THIS AM. 27/00 UTC NAM
APPEARS TOO STRONG/NORTH WITH AFOREMENTIONED WAVE...AS SUCH WL
DISCOUNT/SUBJECTIVELY WEAKEN AND SHUNT SWD IN LIGHT OF MID
TROPOSPHERIC SPEED MAX ALONG OH RVR PER TCVG/KILN VWP AND CENTROID
OF SFC PRES FALLS ACRS ERN KY. INITIAL 5H ZONAL CONFLUENCY WITH
LOWER TROP FLOW WELL VEERED/STRENGTHENED SFC-4KFT PER KIND/KIWX VWP
DENOTING DRYING/SUBSIDENT AIRMASS ESTABLISHING FIRM FOOTHOLD
THROUGH ENTIRE SRN GRTLKS RGN AND INTO NRN EXTENT OF OH
VLY...BODING UNFAVORABLE FOR A SHARP NWD GENUFLECTION OF CURRENT
I70 CORRIDOR SHRA. 06 UTC NAM AND LATEST RAP RUNS APPEAR
MORE REASONABLE IN STRENGTH/POSITIONING...WL CONT WITH DRY
FORECAST TDY AND MONITOR TRENDS THROUGH AM HOURS...AS HIGH END
CHC/LOW LKLY 00 UTC GUID POPS CREATING APPREHENSION. BY DY2 DEEP
JAMES BAY/LWR GRTLKS TROFING DOMINATES WITH ARDENT NRN PLAINS
RIDGING LEADING TO DOWNSTREAM REXED CUT OFF...WITH CRISP/COOL/DRY
FALL AIRMASS. ONLY MINOR TWEAKS TO TEMPS/DPS REQRD.
LONG TERM...
SATURDAY THROUGH WEDNESDAY...THE FORECAST CHALLENGES EARLY INCLUDE
THE DEVELOPMENT OF A CUT OFF LOW DOWNSTREAM OF A TEMPORARY BLOCKING
RIDGE. PREFER THE RECENT PERFORMANCE OF THE ECMWF AND THE CURRENT
HANDLING OF ECMWF WITH THIS SYSTEM. KEPT THE FORECAST DRY AS
ISENTROPIC LEVELS INDICATE LIMITED MOISTURE AVAILABLE FOR THIS
SYSTEM. ALSO...THE BEST LIFT SHOULD REMAIN NORTHEAST OF THE FORECAST
AREA IN THE DEFORMATION ZONE. KEPT TEMPERATURES COOL SUNDAY...WITH
MODERATING TEMPERATURES THROUGH THE END OF THE PERIOD. LOWERED LOW
TEMPERATURES SUNDAY NIGHT GIVEN CLEARING SKIES...LIGHT WINDS...AND A
COOL AND DRY AIRMASS...IDEAL CONDITIONS FOR A SHALLOW RADIATION
INVERSION TO FORM.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK UNTIL 4 PM CDT THIS AFTERNOON FOR INZ003.
MI...RIP CURRENT RISK UNTIL 5 PM EDT THIS AFTERNOON FOR MIZ077.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...AGD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
345 PM CDT THU SEP 27 2012
...UPDATE TO LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 237 PM CDT THU SEP 27 2012
AT THE JET STREAM LEVEL OF 250MB, THERE WAS A 70 TO 80 KNOT JET OVER
EASTERN ARIZONA EXTENDING TO NORTHEASTERN NEW MEXICO, WITH A
NORTHEAST DIRECTION TOWARD SOUTHWEST KANSAS. ANOTHER 70 KNOT JET
WAS FROM NORTH OF KANSAS CITY EAST-SOUTHEASTWARD TO SOUTHERN
ILLINOIS. THERE WAS ALSO A WEAK EASTERLY JET IN THE 70 KNOT RANGE
OVER ONTARIO, WITH YET ANOTHER 90 TO 100KT JET ENTERING EXTREME
NORTHWESTERN NORTH AMERICA OVER THE NORTHWESTERN BRITISH COLUMBIA
PROVIDENCE. THE 500MB CHART SHOWED A TROUGH FROM EASTERN MONTANA
SOUTH INTO SOUTHWESTERN NEW MEXICO. A LOW PRESSURE AREA WAS OVER
NORTHERN COLORADO, WITH A TROUGH EXTENDING EASTWARD OVER NORTHERN
COLORADO INTO NORTH CENTRAL KANSAS. A LARGE MOISTURE FIELD RAN
FROM WESTERN TEXAS NORTH THROUGH THE TEXAS AND OKLAHOMA BORDER,
THEN TURNED EAST INTO SOUTHWESTERN MISSOURI. THE 700MB ANALYSIS
SHOWED ONE TROUGH FROM SOUTHEASTERN KANSAS THROUGH CENTRAL OKLAHOMA
INTO THE NORTHWESTERN TEXAS PANHANDLE. ANOTHER TROUGH WAS FROM
NORTHWESTERN NORTH DAKOTA SOUTH TO A LOW PRESSURE AREA OVER
NORTHERN COLORADO, TO NORTHWESTERN NEW MEXICO. THERE WAS A COOL
POCKET OF +04C AIR OVER SOUTHERN WISCONSIN. A LARGE MOISTURE
FIELD WITH DEW POINT DEPRESSIONS LESS THAN 5C WAS FROM EXTREME
SOUTHWESTERN IDAHO SOUTHEAST TOWARD NORTHWESTERN ARKANSAS. THE
700MB TEMP/WINDS AT DDC WERE +03C/30010KTS. DOWN AT THE 850MB
CHART, A LOW PRESSURE AREA OVER NORTHEASTERN COLORADO HAD A FRONT
EXTENDING TO THE SOUTHEAST DIRECTION TO THE EASTERN TEXAS
PANHANDLE, SWOOPING SOUTHEAST THROUGH SOUTHERN OKLAHOMA, AND THEN
BACK TO THE NORTHEAST INTO SOUTHERN ILLINOIS. A SLIGHT WARM
POCKET OF AIR WAS LODGED OVER THE NORTHERN PLAINS IN NORTHWESTERN
SOUTH DAKOTA WITH +18C TEMPS. ANOTHER COOL TONGUE OF AIR WAS FROM
ONTARIO SOUTHWESTWARD TO EASTERN IOWA, WITH TEMPERATURES AS LOW AS
-03C OVER THE NORTHEASTERN GREAT LAKES. THE 850MB TEMP/WINDS AT
DDC WERE +14C/24007KT RESPECTFULLY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 237 PM CDT THU SEP 27 2012
THE FIRST PRIORITY FOR THIS FORECAST IS THE CHANCE FOR SEVERE STORMS
VERY LATE THIS AFTERNOON AND THIS EVENING. TEMPERATURES AND WINDS
ARE OF A SECONDARY CONCERN. THE SPC DAY ONE OUTLOOK HAS OUR
SOUTHWEST CORNER, SOUTHWEST OF A HAMILTON TO GRANT TO SEWARD LINE,
IN A SLIGHT CHANCE. I THINK THERE COULD BE ONE OR TWO OR THREE
HAIL PRODUCERS IN OUR WEST/SOUTHWEST CORNER, BUT MAINLY AFTER 9 PM CDT.
THE HRRR MODEL HAS JUST MARGINAL CAPE THIS EVENING IN THE 1000
J/KG, THE RUC MODEL HAS LITTLE OR NO 0-6 KM HELICITY, AND FORECAST
SOUNDINGS FROM BOTH THE HRRR AND RUC MODELS FOR A POINT NEAR
RICHFIELD SHOW -5.8 LI`S BY 06Z. IF THERE IS SOME SEVERE, IT WILL
BE A LATE SHOW AFTER 9PM CDT. WE HELD A EMS/KDOT/FEMA CONTACTS,
AND TOLD THEM POSSIBLE HAILERS WITH UP TO GOLF BALL HAIL AFTER 7 PM
CDT, SO THEY SHOULD HAVE PLENTY OF NOTICE.
AFTER THE FIRST ROUND OF MARGINAL SEVERE CONVECTION, THERE IS A GOOD
WAVE MOVING EAST ACROSS OUR CWA AFTER MIDNIGHT. THEREFORE, THERE
WILL BE INCREASING POPS AFTER 06Z, FROM WEST TO EAST. THERE COULD
BE A GOOD WIDESPREAD RAIN EVENT, BUT DID NOT OVERDO THE RAINFALL
QPF SINCE HIGH RAINFALL AMOUNTS WILL SPOTTY SUCH AS THE LAST
SEVERAL PRECIPITATION EVENTS. LAST NIGHT, DOWN NEAR LIBERAL, WE
HAD ONE RAINFALL REPORT OF 3.50 INCHES 2 MILES SOUTH OF LIBERAL
AND ANOTHER REPORT OF 2.61 INCHES OF RAIN FROM THE SOUTH-SOUTHWEST
EDGE OF ROLLA. SO, WIDESPREAD RAIN LIKE THAT IS NOT EXPECTED
AGAIN. THE RUC13 MODEL SOUNDING FOR NEAR ELKHART SHOWED 1.13
INCHES AT 06Z. OUR EASTERN CWA SHOULD STAY CLOUDY TONIGHT WITH
3-5SM FOG, AND THE WEST WILL LIKELY SEE EVEN LOWER LEVEL CLOUDS
IN THE EASTERLY UPSLOPE FLOW. TEMPERATURES WILL NOT FALL QUICKLY
UNDER THE THICK CLOUDS, AND SHOULD ONLY BOTTOM OUT IN THE MID 50S
IN THE WEST AND THE LOWER 60S IN THE SOUTHEAST.
FRIDAY COULD STILL BE WET WITH SCATTERED SHOWERS AND THUNDERSTORMS,
WITH THE BETTER CHANCE IN OUR EASTERN COUNTIES EAST OF A LINE FROM
HAYS TO DODGE CITY TO ASHLAND. THIS MAY BE AN EARLY MORNING THEN
ANOTHER ROUND OF RAIN IN THE AFTERNOON EVENT. POPS WILL BE 40 TO
50 PERCENT EAST OF THAT LINE ABOVE, WITH 30 TO 40 POPS WEST OF THAT
LINE. HOW MUCH RAIN IS ALWAYS THE QUESTION CALLERS SEEM TO ASK,
BUT DO NOT THINK ANY ADDITIONAL HEAVY RAIN WILL FALL ON FRIDAY. THE
UPPER SUPPORT WILL BE PULLING EAST DURING THE AFTERNOON, AND THE
SURFACE FRONT SHOULD BE MOVING SOUTH OUT OF OUR CWA DURING THE
AFTERNOON. LIGHT BUT STEADY UPSLOPE FLOW WILL BE THE MAIN SOURCE
OF PRECIPITATION FRIDAY. FRIDAY AFTERNOON SHOULD BE ANOTHER COOL
ONE, AS TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S IN OUR
EASTERN ZONES OF ELLIS, EDWARDS AND CLARK COUNTIES (AND EAST) AND
IN THE LOWER 70S TO DOWN NEAR 70F DEGREES OUT WEST NEAR THE
COLORADO BORDER NEAR THE STRONGEST UPSLOPE AFFECT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 PM CDT THU SEP 27 2012
FRIDAY NIGHT:
CONVECTION WILL QUICKLY BE ON THE WANE FRIDAY EVENING AS A 90 KT
250 HPA JET STREAK TRAVERSES QUICKLY ACROSS THE STATE AND AS DIURNAL
INSTABILITY RAPIDLY DIMINISHES. AS A RESULT, HAVE RAMPED POPS DOWN SOONER
ACROSS THE REGION BETWEEN FRIDAY EVENING AND TOWARDS MIDNIGHT SATURDAY.
THE NEXT SENSIBLE WEATHER CONCERN HEADING INTO SATURDAY MORNING IS FOG.
BUFKIT/BUFR FORECAST SOUNDINGS SHOW AN ENVIRONMENT THAT IS CONDUCIVE
FOR RADIATIONAL FOG. THIS IS A RESULT OF HIGH PRESSURE BUILDING IN ACROSS
KANSAS AND WINDS BECOMING LIGHT OR EVEN CALM. HAVE INSERTED AREAS OF
FOG IN THE WX GRIDS AS BETTER CONFIDENCE OF FOG VIA THE AFOREMENTIONED
SOUNDINGS AND PLAN VIEW RH PROGS IN THE BOUNDARY LAYER.
SATURDAY THROUGH NEXT THURSDAY:
THE FORECAST WILL BE FAIRLY DRY THROUGH MUCH OF THE PERIOD IN ASSOCIATION
WITH UPPER LEVEL RIDGING, THE WARM PLUME SPREADING EAST, AND LACK OF
REAL SURFACE MOISTURE & CONVERGENCE. THE EXCEPTION TO THIS IS SUNDAY
EVENING. A SHORTWAVE TROUGH SKIRTING ACROSS THE NORTHERN PRAIRIES WILL
USHER IN A COLD FRONT/TROF AXIS WHICH COULD BE THE IMPETUS FOR CONVECTION
DURING THE AFTERNOON AND EARLY EVENING. WILL MAINLY USE THE 12Z ECMWF
FOR GUIDANCE IN CONCERNING THIS CONVECTION FOR NOW. SLIGHT POPS LOOK
REASONABLE FOR NOW AND RESULTED IN NOT MUCH CHANGE FROM THE PREVIOUS
FORECAST.
OTHERWISE, RELATIVELY HIGH 500 HPA HEIGHTS ARE EXPECTED ACROSS WESTERN
KANSAS FOR MUCH OF NEXT WEEK. THE FLOW WILL BECOME MORE PERPENDICULAR
TO THE ROCKIES BY MIDWEEK NEXT WEEK WHICH WILL RESULT IN LOWERING PRESSURES
ACROSS THE LEE OF THE ROCKIES AND A CONTINUED WARM AIR ADVECTION PATTERN
THROUGH THE LOWER ATMOSPHERE. AS A RESULT, EXPECT MODERATING TEMPERATURES
THROUGH NEXT WEEK WITH NEAR TO ABOVE NORMAL HIGHS. THE 12Z ECMWF IS
SHOWING A FAIRLY STRONG COLD FRONT TRAVERSING ACROSS THE KANSAS PRAIRIES
BY NEXT THURSDAY. WILL NOT STRAY FROM WHAT THE ALLBLEND GIVES ME AS
THE VALUES LOOK REASONABLE WITH HIGHS COOLING DOWN INTO THE 70S DEG
F. UPPER LEVEL JET DYNAMICS WITH THIS FRONT LOOKS TO BE FAIRLY BROAD
AND ELONGATED SO ANY SIGNIFICANT SYNOPTIC SCALE LIFT AND ASSOCIATED
RESULTANT PRECIPITATION LOOKS TO REMAIN NORTH OF THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1150 AM CDT THU SEP 27 2012
FOR THIS AFTERNOON, EXPECT MVFR CIGS IN THE BKN-OVC025-030 RANGE
AND VSBYS IN THE 5-6SM BR/HZ RANGE. THERE IS A SLIGHT CHANCE
THROUGH 21Z ANY ONE TAF MAY DIP TO IFR CIGS IN THE BKN008 RANGE,
BUT THOSE CIGS SHOULD BE SHORT LIVED. LIGHT WINDS EARLY WILL
BECOME ESTABLISHED FROM THE EAST AT 10 TO 12 KNOTS THIS AFTERNOON.
THERE IS ALSO A SLIGHT CHANCE FOR STRAY THUNDERSTORMS AFTER 22Z,
ALONG WITH MVFR CIGS. LATER TONIGHT, CLOUDS AND FOG WILL ROLL BACK
IN AFTER 06Z, GENERALLY IN THE MVFR CATER GORY FOR VSBYS IN 3-4SM
BR. LOW STRATUS WILL BRING CIGS IN THE IFR CATEGORY, APPARENTLY IN
THE OVC007 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 73 56 76 / 60 50 20 10
GCK 58 71 55 75 / 60 40 10 10
EHA 57 72 55 76 / 70 40 10 10
LBL 58 73 56 76 / 70 50 20 10
HYS 58 73 55 76 / 40 50 10 10
P28 62 75 60 77 / 60 60 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURKE
SHORT TERM...BURKE
LONG TERM...SUGDEN
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
319 PM CDT THU SEP 27 2012
.DISCUSSION...
20Z WATER VAPOR SHOW AN UPPER LEVEL DISTURBANCE SPINNING OVER
NORTHERN CO. 500MB PROFILER DATA SUGGESTS A WEAK DISTURBANCE IS
TRAVERSING THE STATE OVER A PRETTY GOOD DEWPOINT GRADIENT ACROSS
EAST CENTRAL KS. MEANWHILE A SFC RIDGE OF HIGH PRESSURE EXTENDED
FROM THE UPPER MIDWEST INTO THE CENTRAL PLAINS...HELPING TO CREATE
THE DEWPOINT GRADIENT.
FOR TONIGHT AND FRIDAY...THE MODELS HAVE BEEN IN REASONABLE
AGREEMENT THAT A SLIGHTLY UNSTABLE ATMOSPHERE WITH WEAK FORCING
WOULD PERSIST. WITH THE DEEPER MOISTURE PROGGED BY THE MODELS TO BE
MAINLY ACROSS SOUTHERN KS...THINKING IS PRECIP CHANCES WILL BE
BETTER TO THE SOUTH WITH SOME LOW POPS ACROSS EAST CENTRAL KS. THE
CONVECTION THIS AFTERNOON APPEARS TO BE MAINLY DRIVEN BY THE WEAK
DISTURBANCE AND DAYTIME HEATING ALONG THE DEWPOINT GRADIENT. AS THE
DISTURBANCE PASSES EAST AND CONVERGENCE ALONG THE DEWPOINT GRADIENT
WEAKENS...WOULD EXPECT CONVECTION TO DIMINISH THIS EVENING BEFORE
THE NEXT IMPULSE KICKS OUT FROM CO. LOWS TONIGHT SHOULD RANGE FROM
THE UPPER 40S NEAR THE NEB STATE LINE WHERE LESS CLOUD COVER AND
MUCH DRYER AIR COULD HELP TEMPS DROP. HAVE LOWS IN THE UPPER 50S
ACROSS EAST CENTRAL KS EXPECTING OVERCAST SKIES TO PERSIST FOR MUCH
OF THE NIGHT AND THE BOUNDARY LAYER TO REMAIN A LITTLE MORE MOIST.
HIGHS FRIDAY ARE EXPECTED TO BE SIMILAR TO TODAYS WITH NO REAL
CHANGE IN AIRMASS AND AN EASTERLY WIND PERSISTING WITH PARTLY SUNNY
SKIES. THEREFORE LOOKING AT HIGHS IN THE MID TO UPPER 70S.
WOLTERS
EXTENDED (SATURDAY THROUGH THURSDAY)...SHORTWAVE RIDGING IN BETWEEN
TWO UPPER TROUGHS WILL RESIDE OVER THE CWA FOR THE
WEEKEND...RESULTING IN DRY AND QUIET WEATHER FOR THE AREA. THE
APPROACHING WEAK ASCENT FROM A MODERATE UPPER JET AND AN ASSOCIATED
COLD FRONT WILL ARRIVE OVER THE REGION ON SUNDAY NIGHT INTO MONDAY
MORNING. A BRIEF PERIOD OF INCREASED CLOUD COVER MAY BE NOTED WITH
THIS FEATURE...BUT DRY AIR IN THE H5-7 LAYER SHOULD PROHIBIT ANY
MEANINGFUL PRECIPITATION CHANCES. THEREAFTER...DRY WEATHER IS
EXPECTED THROUGH THE WORK WEEK WITH A DRY ATMOSPHERE IN PLACE...AND
THE CWA REMAINING ON THE SOUTHERN PERIPHERY OF ZONAL FLOW WITH THE
PRIMARY WEATHER SYSTEMS RESIDING TO THE NORTH. ANOTHER COLD FRONT IS
PROJECTED TO SLIDE INTO THE AREA ON THURSDAY...BUT LOOKS LIKE A DRY
PASSAGE ATTM. AS FOR TEMPERATURES...A GRADUAL WARMING TREND FOR
AFTERNOON HIGHS IS ON TAP THIS WEEKEND THROUGH WEDNESDAY WITH
READINGS IN THE UPPER 70S TO THE MIDDLE 80S. SLIGHTLY COOLER WEATHER
WILL RETURN BEHIND THE FRONTAL BOUNDARY ON THURSDAY.
BLAIR
&&
.AVIATION...
MODELS CONTINUE TO SHOW THE DEEPER MOISTURE REMAINING JUST SOUTH OF
THE TERMINALS...SO EXPECT PRECIP CHANCES TO BE CONFINED TO AREAS
SOUTH OF FOE AND MHK. SOME MVFR CIGS HAVE TRIED TO DRIFT NORTH INTO
THE TERMINALS OVER THE LAST HOUR OR SO. THE LATEST RAP AND NAM RH
PROGS SUGGEST THE LOW LEVEL RH WILL GRADUALLY PUSH SOUTH...SO THINK
VFR CONDITIONS WILL PREVAIL.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
306 PM CDT THU SEP 27 2012
...UPDATED FOR THE SHORT TERM AND SYNOPSIS...
.SYNOPSIS...
ISSUED AT 237 PM CDT THU SEP 27 2012
AT THE JET STREAM LEVEL OF 250MB, THERE WAS A 70 TO 80 KNOT JET OVER
EASTERN ARIZONA EXTENDING TO NORTHEASTERN NEW MEXICO, WITH A
NORTHEAST DIRECTION TOWARD SOUTHWEST KANSAS. ANOTHER 70 KNOT JET
WAS FROM NORTH OF KANSAS CITY EAST-SOUTHEASTWARD TO SOUTHERN
ILLINOIS. THERE WAS ALSO A WEAK EASTERLY JET IN THE 70 KNOT RANGE
OVER ONTARIO, WITH YET ANOTHER 90 TO 100KT JET ENTERING EXTREME
NORTHWESTERN NORTH AMERICA OVER THE NORTHWESTERN BRITISH COLUMBIA
PROVIDENCE. THE 500MB CHART SHOWED A TROUGH FROM EASTERN MONTANA
SOUTH INTO SOUTHWESTERN NEW MEXICO. A LOW PRESSURE AREA WAS OVER
NORTHERN COLORADO, WITH A TROUGH EXTENDING EASTWARD OVER NORTHERN
COLORADO INTO NORTH CENTRAL KANSAS. A LARGE MOISTURE FIELD RAN
FROM WESTERN TEXAS NORTH THROUGH THE TEXAS AND OKLAHOMA BORDER,
THEN TURNED EAST INTO SOUTHWESTERN MISSOURI. THE 700MB ANALYSIS
SHOWED ONE TROUGH FROM SOUTHEASTERN KANSAS THROUGH CENTRAL OKLAHOMA
INTO THE NORTHWESTERN TEXAS PANHANDLE. ANOTHER TROUGH WAS FROM
NORTHWESTERN NORTH DAKOTA SOUTH TO A LOW PRESSURE AREA OVER
NORTHERN COLORADO, TO NORTHWESTERN NEW MEXICO. THERE WAS A COOL
POCKET OF +04C AIR OVER SOUTHERN WISCONSIN. A LARGE MOISTURE
FIELD WITH DEW POINT DEPRESSIONS LESS THAN 5C WAS FROM EXTREME
SOUTHWESTERN IDAHO SOUTHEAST TOWARD NORTHWESTERN ARKANSAS. THE
700MB TEMP/WINDS AT DDC WERE +03C/30010KTS. DOWN AT THE 850MB
CHART, A LOW PRESSURE AREA OVER NORTHEASTERN COLORADO HAD A FRONT
EXTENDING TO THE SOUTHEAST DIRECTION TO THE EASTERN TEXAS
PANHANDLE, SWOOPING SOUTHEAST THROUGH SOUTHERN OKLAHOMA, AND THEN
BACK TO THE NORTHEAST INTO SOUTHERN ILLINOIS. A SLIGHT WARM
POCKET OF AIR WAS LODGED OVER THE NORTHERN PLAINS IN NORTHWESTERN
SOUTH DAKOTA WITH +18C TEMPS. ANOTHER COOL TONGUE OF AIR WAS FROM
ONTARIO SOUTHWESTWARD TO EASTERN IOWA, WITH TEMPERATURES AS LOW AS
-03C OVER THE NORTHEASTERN GREAT LAKES. THE 850MB TEMP/WINDS AT
DDC WERE +14C/24007KT RESPECTFULLY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 237 PM CDT THU SEP 27 2012
THE FIRST PRIORITY FOR THIS FORECAST IS THE CHANCE FOR SEVERE STORMS
VERY LATE THIS AFTERNOON AND THIS EVENING. TEMPERATURES AND WINDS
ARE OF A SECONDARY CONCERN. THE SPC DAY ONE OUTLOOK HAS OUR
SOUTHWEST CORNER, SOUTHWEST OF A HAMILTON TO GRANT TO SEWARD LINE,
IN A SLIGHT CHANCE. I THINK THERE COULD BE ONE OR TWO OR THREE
HAIL PRODUCERS IN OUR WEST/SOUTHWEST CORNER, BUT MAINLY AFTER 9 PM CDT.
THE HRRR MODEL HAS JUST MARGINAL CAPE THIS EVENING IN THE 1000
J/KG, THE RUC MODEL HAS LITTLE OR NO 0-6 KM HELICITY, AND FORECAST
SOUNDINGS FROM BOTH THE HRRR AND RUC MODELS FOR A POINT NEAR
RICHFIELD SHOW -5.8 LI`S BY 06Z. IF THERE IS SOME SEVERE, IT WILL
BE A LATE SHOW AFTER 9PM CDT. WE HELD A EMS/KDOT/FEMA CONTACTS,
AND TOLD THEM POSSIBLE HAILERS WITH UP TO GOLF BALL HAIL AFTER 7 PM
CDT, SO THEY SHOULD HAVE PLENTY OF NOTICE.
AFTER THE FIRST ROUND OF MARGINAL SEVERE CONVECTION, THERE IS A GOOD
WAVE MOVING EAST ACROSS OUR CWA AFTER MIDNIGHT. THEREFORE, THERE
WILL BE INCREASING POPS AFTER 06Z, FROM WEST TO EAST. THERE COULD
BE A GOOD WIDESPREAD RAIN EVENT, BUT DID NOT OVERDO THE RAINFALL
QPF SINCE HIGH RAINFALL AMOUNTS WILL SPOTTY SUCH AS THE LAST
SEVERAL PRECIPITATION EVENTS. LAST NIGHT, DOWN NEAR LIBERAL, WE
HAD ONE RAINFALL REPORT OF 3.50 INCHES 2 MILES SOUTH OF LIBERAL
AND ANOTHER REPORT OF 2.61 INCHES OF RAIN FROM THE SOUTH-SOUTHWEST
EDGE OF ROLLA. SO, WIDESPREAD RAIN LIKE THAT IS NOT EXPECTED
AGAIN. THE RUC13 MODEL SOUNDING FOR NEAR ELKHART SHOWED 1.13
INCHES AT 06Z. OUR EASTERN CWA SHOULD STAY CLOUDY TONIGHT WITH
3-5SM FOG, AND THE WEST WILL LIKELY SEE EVEN LOWER LEVEL CLOUDS
IN THE EASTERLY UPSLOPE FLOW. TEMPERATURES WILL NOT FALL QUICKLY
UNDER THE THICK CLOUDS, AND SHOULD ONLY BOTTOM OUT IN THE MID 50S
IN THE WEST AND THE LOWER 60S IN THE SOUTHEAST.
FRIDAY COULD STILL BE WET WITH SCATTERED SHOWERS AND THUNDERSTORMS,
WITH THE BETTER CHANCE IN OUR EASTERN COUNTIES EAST OF A LINE FROM
HAYS TO DODGE CITY TO ASHLAND. THIS MAY BE AN EARLY MORNING THEN
ANOTHER ROUND OF RAIN IN THE AFTERNOON EVENT. POPS WILL BE 40 TO
50 PERCENT EAST OF THAT LINE ABOVE, WITH 30 TO 40 POPS WEST OF THAT
LINE. HOW MUCH RAIN IS ALWAYS THE QUESTION CALLERS SEEM TO ASK,
BUT DO NOT THINK ANY ADDITIONAL HEAVY RAIN WILL FALL ON FRIDAY. THE
UPPER SUPPORT WILL BE PULLING EAST DURING THE AFTERNOON, AND THE
SURFACE FRONT SHOULD BE MOVING SOUTH OUT OF OUR CWA DURING THE
AFTERNOON. LIGHT BUT STEADY UPSLOPE FLOW WILL BE THE MAIN SOURCE
OF PRECIPITATION FRIDAY. FRIDAY AFTERNOON SHOULD BE ANOTHER COOL
ONE, AS TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S IN OUR
EASTERN ZONES OF ELLIS, EDWARDS AND CLARK COUNTIES (AND EAST) AND
IN THE LOWER 70S TO DOWN NEAR 70F DEGREES OUT WEST NEAR THE
COLORADO BORDER NEAR THE STRONGEST UPSLOPE AFFECT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 322 AM CDT THU SEP 27 2012
FRIDAY THROUGH SATURDAY NIGHT:
CHALLENGING FORECAST WITH RESPECT TO PRECIPITATION DURING THIS
PERIOD...MAINLY BECAUSE IT IS DIFFICULT TO HONE IN ON A STRONG
SIGNAL FOR LARGE SCALE ASCENT...AND WHAT SIGNAL THERE IS FOR UPWARD
VERTICAL MOTION IS DIFFERENT DEPENDING ON WHICH GLOBAL MODEL ONE IS
LOOKING AT. ALL THAT BEING SAID...WEAK LOW LEVEL CONVERGENCE FRIDAY
INTO FRIDAY EVENING COMBINED WITH RICH LOW LEVEL MOISTURE (SURFACE
DEWPOINTS IN THE LOWER 60S DEGF)...AND BROAD UPPER TROPOSPHERIC JET
MAX FROM NEW MEXICO INTO THE SOUTHERN/CENTRAL GREAT PLAINS (WHICH IS
ENHANCED DUE TO THE REMNANTS OF TROPICAL CYCLONE MIRIAM).
ALSO...MID LEVEL TEMPERATURES WILL CONTINUE TO BE COOL WITH 700MB
TEMPS AROUND +4 OR +5C...SO ANY DIURNAL INSOLATION WILL ENHANCE THE
PROBABILITY FOR SHOWERS/THUNDERSTORMS JUST ABOUT ANYWHERE AMIDST THE
MOIST SFC-700MB AIRMASS. EVENTUALLY...THE UPPER TROPOSPHERIC JET
WILL SHIFT EAST INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEASTERN CONUS
AND PROBABILITY OF PRECIPITATION WILL DIMINISH...ESPECIALLY BY
SATURDAY. HAVE DECIDED TO INCREASE POPS INTO LIKELY RANGE (60 POPS)
MAINLY SOUTH CENTRAL KANSAS (SOUTHEAST OF ENGLEWOOD-STAFFORD LINE)
CLOSER TO THE LOW LEVEL DEFORMATION/CONVERGENCE ZONE. GIVEN THE
SOMEWHAT COOL LOWER TROPOSPHERE AND PROPENSITY FOR CLOUDS AND
PRECIPITATION...HIGHS IN THE LOWER TO MID 70S LOOK GOOD FOR FRIDAY.
THE SAME CAN BE SAID FOR SATURDAY WITH SIMILAR TEMPERATURES IN THE
FORECAST WITH 850/700MB TEMPS AVERAGING +16/+5C ACROSS SOUTHWEST
KANSAS. VERY LIGHT WINDS (IF NOT CALM AT TIMES), HIGH DEWPOINTS IN
THE UPPER 50S/LOWER 60S, AND WET GROUNDS WILL CONTINUE TO SUPPORT
DEVELOPMENT OF AREAS DENSE FOG BOTH FRIDAY NIGHT AND SATURDAY NIGHT.
WILL NOT YET INSERT MENTION OF FOG IN THE GRIDS FOR THESE PERIODS
AND LET FUTURE SHIFTS ASSESS THIS FORECAST ELEMENT.
SUNDAY THROUGH WEDNESDAY:
A WEAK NORTHWEST FLOW DISTURBANCE WILL MOVE SOUTH-SOUTHEAST THROUGH
THE HIGH PLAINS SUNDAY WHICH WILL PROVIDE ANOTHER SLIGHT CHANCE
WIDELY SCATTERED SURFACE-BASED CONVECTION. THE LATEST ALLBLEND
GUIDANCE YIELDED 20 POPS FOR MUCH OF WEST CENTRAL/SOUTHWEST KANSAS
FOR THE SUNDAY PERIOD AND WILL NOT DEVIATE FROM THIS. AFTER THIS
WEAK WAVE MOVES THROUGH...AN EXTENDED PERIOD OF DRY WEATHER IS
EXPECTED AS A PRONOUNCED UPPER LEVEL HIGH BECOMES ESTABLISHED ACROSS
THE SOUTHWESTERN CONUS. HIGH TEMPERATURES EARLY NEXT WEEK WILL
AVERAGE LOWER TO MID 80S FOR MUCH OF THE REGION WITH THE DOMINANT
UPPER LEVEL JET WELL TO THE NORTH ALONG THE US-CANADA BORDER
EARLY-MID NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1150 AM CDT THU SEP 27 2012
FOR THIS AFTERNOON, EXPECT MVFR CIGS IN THE BKN-OVC025-030 RANGE
AND VSBYS IN THE 5-6SM BR/HZ RANGE. THERE IS A SLIGHT CHANCE
THROUGH 21Z ANY ONE TAF MAY DIP TO IFR CIGS IN THE BKN008 RANGE,
BUT THOSE CIGS SHOULD BE SHORT LIVED. LIGHT WINDS EARLY WILL
BECOME ESTABLISHED FROM THE EAST AT 10 TO 12 KNOTS THIS AFTERNOON.
THERE IS ALSO A SLIGHT CHANCE FOR STRAY THUNDERSTORMS AFTER 22Z,
ALONG WITH MVFR CIGS. LATER TONIGHT, CLOUDS AND FOG WILL ROLL BACK
IN AFTER 06Z, GENERALLY IN THE MVFR CATER GORY FOR VSBYS IN 3-4SM
BR. LOW STRATUS WILL BRING CIGS IN THE IFR CATEGORY, APPARENTLY IN
THE OVC007 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 73 57 76 / 60 50 30 20
GCK 58 72 56 75 / 60 40 30 20
EHA 57 74 56 76 / 70 40 30 20
LBL 58 73 57 77 / 70 50 30 20
HYS 58 74 56 75 / 40 50 30 10
P28 62 75 60 76 / 60 60 40 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURKE
SHORT TERM...BURKE
LONG TERM...UMSCHEID
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1215 PM CDT THU SEP 27 2012
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
MODELS CONTINUE TO SHOW THE DEEPER MOISTURE REMAINING JUST SOUTH OF
THE TERMINALS...SO EXPECT PRECIP CHANCES TO BE CONFINED TO AREAS
SOUTH OF FOE AND MHK. SOME MVFR CIGS HAVE TRIED TO DRIFT NORTH INTO
THE TERMINALS OVER THE LAST HOUR OR SO. THE LATEST RAP AND NAM RH
PROGS SUGGEST THE LOW LEVEL RH WILL GRADUALLY PUSH SOUTH...SO THINK
VFR CONDITIONS WILL PREVAIL.
WOLTERS
&&
.PREV DISCUSSION... /345 AM CDT THU SEP 27 2012/
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE NORTHEAST
ACROSS SOUTHEAST KANSAS INTO MISSOURI IN AN AREA OF ISENTROPIC LIFT
OVER THE FRONTAL BOUNDARY IN OKLAHOMA DUE TO THE LOW LEVEL JET.
FURTHER NORTH SKIES HAVE BRIEFLY CLEARED NORTH OF INTERSTATE 70 AND
ALLOWED FOG TO QUICKLY FORM HOWEVER HIGH CLOUDS CONTINUE TO SPREAD
NORTHWARD AND SHOULD THICKEN OVER TIME. THIS SHOULD KEEP THE FOG
FROM BECOMING WIDESPREAD AND WILL ADD A COUPLE OF HOURS OF PATCHY
FOG TO THE FORECAST. MODELS ARE IN GENERAL AGREEMENT FOR TODAY WITH
KEEPING THE BOUNDARY SOUTH IN OKLAHOMA AND MOST OF THE PRECIPITATION
SOUTH OF THE CWA FOR THE BULK OF THE DAY. THE UPPER LOW/TROUGH OVER
THE ROCKIES WILL BEGIN TO MOVE EASTWARD THIS EVENING INTO THE HIGH
PLAINS WHILE SOME PIECES OF ENERGY MOVE EASTWARD ACROSS THE STATE.
WITH THE FRONTAL BOUNDARY AND DEEPER MOISTURE SOUTH BEST CHANCES OF
RAINFALL WILL BE MAINLY SOUTH OF INTERSTATE 70 WITH THE HIGHEST
CHANCES NEAR THE OKLAHOMA BORDER. THE UPPER TROUGH WILL MOVE SLOWLY
EASTWARD BEFORE WEAKENING IN THE AFTERNOON. DRIER AIR AT THE SURFACE
WILL MOVE IN FROM THE NORTHEAST DUE TO SURFACE HIGH FROM THE GREAT
LAKES SOUTHWEST INTO NORTHEAST KANSAS. LOBES OF ENERGY WILL MOVE
ACROSS THE AREA DURING THE DAY. THIS WILL BRING A CHANCE OF
THUNDERSTORMS TO AREAS MAINLY SOUTH OF INTERSTATE 70 AND ACROSS
PARTS OF NORTH CENTRAL KANSAS. FRIDAY NIGHT LOOKING DRY WITH THE
FRONT AND UPPER SUPPORT OVER OKLAHOMA AND EASTERLY WINDS ADVECTING
DRIER AIR INTO NORTHEAST KANSAS.
FOR THE WEEKEND WEAK UPPER FLOW FROM THE NORTHWEST WILL SEE SOME
RIDGING BETWEEN TWO UPPER TROUGHS ONE MOVING ACROSS THE DAKOTAS AND
THE OTHER IN THE NORTHEAST. SHOULD END OF BEING FAIRLY NICE WITH
HIGHS IN THE UPPER 70S SATURDAY AND SUNDAY.
MONDAY THROUGH WEDNESDAY THE THE UPPER FLOW WILL TRANSITION FROM
NORTHWEST ON MONDAY TO A ZONAL FLOW BY WEDNESDAY. THE MAIN BELT OF
THE WESTERLIES WILL BE NORTH OVER THE DAKOTAS. EXPECTING DRY WEATHER
THROUGH THIS TIME PERIOD WITH TEMPERATURES ABOVE NORMAL IN THE LOW
TO MID 80S.
53
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
536 PM EDT THU SEP 27 2012
.SYNOPSIS...
SLOW MOVING FRONT MOVES EAST OF MOUNTAINS FRIDAY MORNING. UPPER
WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE
FRIDAY. DRIER AIR FILTERS IN FROM THE NORTHWEST LATE FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL UPDATE POPS AND SKY COVER FOR LATE THIS AFTERNOON AND EVENING
TO BETTER REPRESENT CURRENT RADAR AND SATELLITE TRENDS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
WILL BE DEALING WITH AMPLIFYING UPR TROF OVER THE AREA THROUGH THE
WEEKEND. THIS WILL ALLOW PESKY SFC FRONT TO FINALLY GET THE BOOT S
FRI NIGHT. THERE ARE SOME MODEL DISCREPANCIES REGARDING THE SPEED OF
THIS...WITH THE NAM SLOWER THAN MOST OF THE OTHER MDLS. IT SEEMS TO
BE TOO STRONG WITH WAVE ON THE BOUNDARY AS MOST OF THE MDLS KEEP
THINGS MOVING. WILL HEDGE TOWARD FASTER CONSENSUS BUT HOLD SOME SCHC
BACK A HAIR TO GIVE NAM A NOD. EXPECT MUCH OF SHRA TO BE CONFINED TO
S MTNS AND SW VA THOUGH. MARKED DRYING IN ATMOSPHERIC COLUMN WITH
FROPA SHOULD ALLOW MOST PLACES TO CLR IN THE EVE BEFORE SOME HIGHER
CLDS TRY TO FILTER IN FROM NW LATE. EXCEPTION BEING SW VA WHERE
LINGERING LLVL MOISTURE MAY HOLD IN CLDS INTO SAT MORNING.
UPR LOW WILL DROP S INTO LWR LAKES SAT WITHIN AMPLIFYING TROF. MDLS
ARE IN DECENT AGREEMENT WITH THIS BUT DIFFER SLIGHTLY WITH EXACT
POSITION AND EXTENT OF DEEPER MOISTURE. WILL BE WATCHING VARIOUS
SPOKES OF ENERGY DIVING SE FROM UPR LOW LATER ON SAT AND AGAIN ON
SUN. APPEARS THE FIRST WILL HAVE LITTLE MOISTURE TO WORK WITH AND BE
LEFT MAINLY CLDS ACROSS SE OH AND N WV. DID LEAVE SOME SCHC POPS
ACROSS THOSE AREAS WITH MDLS SHOWING SFC LOW DEVELOPMENT OVER UPR OH
VALLEY SAT NIGHT. THINK NAM...HOWEVER...IS TOO DEVELOPED WITH THIS
FEATURE AS IT ALSO SHOWS QUITE H5 VORT MAX AS WELL.
SHOULD SEE MORE OF A DRY SLOT WORK THROUGH EARLY SUN...AHEAD OF
ANOTHER PIECE OF ENERGY DIVING SE. THIS ONE LOOKS TO HAVE MORE OF A
SFC BOUNDARY TO FOLLOW...WITH NOTICEABLE CAA TO FOLLOW. A THIN BAND
OF DEEPER MOISTURE...COMBINED WITH INCREASING LAPSE RATES...MAY
ALLOW FOR A SHRA OR TWO IN AFTN ACROSS THE AREA AND HAVE SOME SCHC
TO COVER. THINK N AREAS STAND BEST SHOT OF THIS.
FOR TEMPS...ROLLED WITH COOLER MAV ACROSS N FRI NIGHT WHERE SOME
CLEARING SHOULD ALLOW TEMPS TO DROP NICELY INTO THE 40S. KEPT SW VA
AND S WV ON MILD SIDE WITH LINGERING LLVL MOISTURE. GUIDANCE TIGHTLY
CLUSTERED FOR HIGHS SAT BUT WOULD NOT BE SURPRISED TO SEE AREA DO A
LITTLE BETTER THAN GUIDANCE SUGGESTS IF MORE SUN IS REALIZED.
INHERITED NUMBERS LOOKED DECENT REST OF THE WAY AND BLENDED IN WITH
A MODEL CONSENSUS. SUN...THOUGH...COULD BE A BIT MILDER THAN FCST
SHOULD WAA AHEAD OF FRONTAL BOUNDARY BE GREATER THAN CURRENT
THINKING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
WENT ALONG WITH EC MODELS AS SUGGESTED BY HPC FOR THE EXTENDED
PERIOD. CLOSED H500 LOW OVER THE EASTERN GREAT LAKES WILL LIFT OUT
SUNDAY NIGHT/MONDAY. EASTERN H500 TROUGH LIFTS OUT
THEREAFTER...WITH MAIN BAND OF WESTERLIES PUSHING NORTH.
HOWEVER...STOUT UPPER HIGH RETROGRADES ACROSS THE ATLANTIC TOWARDS
THE SOUTHEAST U.S. AFTER SUNDAY. THE SOUTHERLY FLOW INDUCED ACROSS
THE SOUTHERN U.S. WILL PUSH MOISTURE NORTHWARD. THE FIRST SLUG
SHOULD MAINLY STAY OFF TO OUR EAST...KEPT THERE BY AN H500 SHORTWAVE
DROPPING IN FROM THE NORTHWEST. A MORE SIGNIFICANT CHANCE OF RAIN
MAY ARRIVE AREAWIDE BY WEDNESDAY NIGHT/THURSDAY AS A SHEARING UPPER
LOW LIFTS ACROSS THE MISSISSIPPI AND OHIO VALLEYS.
LEFT LINGERING LOW CHANCE POPS IN THE NORTHEAST COUNTIES SUNDAY
EVENING AS THE UPPER LOW DEPART...THEN A DRY INTERLUDE MONDAY/MONDAY
EVENING AS A WEAK SURFACE HIGH MOVES THROUGH. LIMITED POPS TO THE
EASTERN SLOPES WITH THE INITIAL SHOT OF MOISTURE MONDAY NIGHT INTO
TUESDAY MORNING. THEN...DRY AND WARMER WITH ZONAL FLOW. POPS
INCREASE FROM SOUTH TO NORTH WEDNESDAY NIGHT/THURSDAY. HELD OFF ON
THUNDER FOR NOW ALTHOUGH THERE MAY BE A TOUCH OF INSTABILITY.
MEX AND ENSEMBLE TEMPERATURES WERE GENERALLY IN DECENT AGREEMENT AND
DID NOT STRAY FAR.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS
AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z.
MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS
AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS
LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY.
THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT
MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE
CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH
HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS
AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN
SHOWERS EARLY THROUGH AROUND 20Z.
ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR
IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL
ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW
STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY
LIFTING INTO 16Z LATE FRIDAY MORNING.
AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS
DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT.
AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE
EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS
DEVELOPMENT AND DURATION MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M L M L M M M M M M L L
HTS CONSISTENCY M L M M M M M M M M M M
BKW CONSISTENCY H M M M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M H L M
PKB CONSISTENCY M M M M M M M M M M H M
CKB CONSISTENCY M M L L M M M M M M L L
AFTER 00Z SATURDAY...
OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER
SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST
VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30/LS/CL
NEAR TERM...RPY
SHORT TERM...30/LS
LONG TERM...CL
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
328 PM EDT THU SEP 27 2012
.SYNOPSIS...
SLOW MOVING FRONT MOVES EAST OF MOUNTAINS FRIDAY MORNING. UPPER
WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE
FRIDAY. DRIER AIR FILTERS IN FROM THE NORTHWEST LATE FRIDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
A QUASI STATIONARY FRONTAL BOUNDARY MEANDERS ACROSS WV TONIGHT.
MODELS SUGGEST IT WILL MOVE EAST OF THE MOUNTAINS BY 12Z FRIDAY.
SYNOPTIC MODELS HAVE NOT HANDLE PCPN WELL TODAY. BASED POPS/WX ON
THE HIGH RESOLUTION MODELS...ESPECIALLY THE HRRR AND THE WRFARW
WHICH BRING SCATTERED SHOWERS ACROSS THE AREA THIS EVENING
DIMINISHING OVERNIGHT WITH NO MENTION OF THUNDER.
MEANTIME...ABUNDANT LOW LEVEL MOISTURE WITH NOT MUCH UPPER LEVEL
SUPPORT SHOULD TRANSLATE INTO WIDESPREAD LOW LEVEL CLOUDS...AND
PERHAPS DENSE FOG OVER HIGHER ELEVATIONS OVERNIGHT. THESE CLOUDS
WILL STAND STRONG THROUGH AT LEAST 13Z BEFORE START TO DISSIPATE
FRIDAY MORNING. THESE FEATURES ARE DEPICTED WITH HIGH CONFIDENCE
BY THE SREF PROBABILITIES...AND NAM/RUC/GFS SOUNDING PROFILES.
A SLIGHTLY DRIER AIRMASS FILTERS IN FROM THE NORTHWEST AS THE H85
FLOW BECOMES NORTHWEST AS SHOWN BY THE CMC/NAM/GFS/ECWF FRIDAY
AFTERNOON...PERHAPS PUSHING EAST THE AFOREMENTIONED CLOUDS...AND
SPREADING CLEARING FROM NORTHWEST TO SOUTHEAST FRIDAY EVENING.
HOWEVER...A WEAK VORT MAX PASSES SOUTH OF THE AREA FRIDAY. KEPT
LIKELY POPS ACROSS THE VIRGINIA COUNTIES FRIDAY AFTERNOON.
WITH PLENTY OF CLOUDS OVERNIGHT...AND JUST A DEGREE CELSIUS LOWER
THAN PREVIOUS NIGHT AT H850...EXPECT NO RADIATIONAL COOLING AND
SLIGHTLY ABOVE NORMAL TEMPERATURES...EXCEPT FOR CRW...GENERALLY
IN THE LOW 60S...RANGING TO THE MID 50S HIGHEST ELEVATIONS.
THEREFORE...WENT WITH THE WARMER NUMBERS BETWEEN THE MET/MAV
GUIDANCE FOR LOWS TONIGHT. HIGH ON FRIDAY WILL DEPEND ON HOW
QUICKLY CLEARING SPREAD EAST SOUTHEAST. THEREFORE...KEEP HIGHER
TEMPS ACROSS SOUTHEAST OH...GENERALLY IN THE MID 70S...RANGING
INTO THE MID 60S HIGHEST ELEVATIONS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
WILL BE DEALING WITH AMPLIFYING UPR TROF OVER THE AREA THROUGH THE
WEEKEND. THIS WILL ALLOW PESKY SFC FRONT TO FINALLY GET THE BOOT S
FRI NIGHT. THERE ARE SOME MDL DISCREPANCIES REGARDING THE SPEED OF
THIS...WITH THE NAM SLOWER THAN MOST OF THE OTHER MDLS. IT SEEMS TO
BE TOO STRONG WITH WAVE ON THE BOUNDARY AS MOST OF THE MDLS KEEP
THINGS MOVING. WILL HEDGE TOWARD FASTER CONCENSUS BUT HOLD SOME SCHC
BACK A HAIR TO GIVE NAM A NOD. EXPECT MUCH OF SHRA TO BE CONFINED TO
S MTNS AND SW VA THOUGH. MARKED DRYING IN ATMOSPHERIC COLUMN WITH
FROPA SHOULD ALLOW MOST PLACES TO CLR IN THE EVE BEFORE SOME HIGHER
CLDS TRY TO FILTER IN FROM NW LATE. EXCEPTION BEING SW VA WHERE
LINGERING LLVL MOISTURE MAY HOLD IN CLDS INTO SAT MORNING.
UPR LOW WILL DROP S INTO LWR LAKES SAT WITHIN AMPLIFYING TROF. MDLS
ARE IN DECENT AGREEMENT WITH THIS BUT DIFFER SLIGHTLY WITH EXACT
POSITION AND EXTENT OF DEEPER MOISTURE. WILL BE WATCHING VARIOUS
SPOKES OF ENERGY DIVING SE FROM UPR LOW LATER ON SAT AND AGAIN ON
SUN. APPEARS THE FIRST WILL HAVE LITTLE MOISTURE TO WORK WITH AND BE
LEFT MAINLY CLDS ACROSS SE OH AND N WV. DID LEAVE SOME SCHC POPS
ACROSS THOSE AREAS WITH MDLS SHOWING SFC LOW DEVELOPMENT OVER UPR OH
VALLEY SAT NIGHT. THINK NAM...HOWEVER...IS TOO DEVELOPED WITH THIS
FEATURE AS IT ALSO SHOWS QUITE H5 VORT MAX AS WELL.
SHOULD SEE MORE OF A DRY SLOT WORK THROUGH EARLY SUN...AHEAD OF
ANOTHER PIECE OF ENERGY DIVING SE. THIS ONE LOOKS TO HAVE MORE OF A
SFC BOUNDARY TO FOLLOW...WITH NOTICEABLE CAA TO FOLLOW. A THIN BAND
OF DEEPER MOISTURE...COMBINED WITH INCREASING LAPSE RATES...MAY
ALLOW FOR A SHRA OR TWO IN AFTN ACROSS THE AREA AND HAVE SOME SCHC
TO COVER. THINK N AREAS STAND BEST SHOT OF THIS.
FOR TEMPS...ROLLED WITH COOLER MAV ACROSS N FRI NIGHT WHERE SOME
CLRING SHOULD ALLOW TEMPS TO DROP NICELY INTO THE 40S. KEPT SW VA
AND S WV ON MILD SIDE WITH LINGERING LLVL MOISTURE. GUIDANCE TIGHTLY
CLUSTERED FOR HIGHS SAT BUT WOULD NOT BE SURPRISED TO SEE AREA DO A
LITTLE BETTER THAN GUIDANCE SUGGESTS IF MORE SUN IS REALIZED.
INHERITED NUMBERS LOOKED DECENT REST OF THE WAY AND BLENDED IN WITH
A MDL CONSENSUS. SUN...THOUGH...COULD BE A BIT MILDER THAN FCST
SHOULD WAA AHEAD OF FRONTAL BOUNDARY BE GREATER THAN CURRENT
THINKING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
WENT ALONG WITH EC MODELS AS SUGGESTED BY HPC FOR THE EXTENDED
PERIOD. CLOSED H500 LOW OVER THE EASTERN GREAT LAKES WILL LIFT OUT
SUNDAY NIGHT/MONDAY. EASTERN H500 TROUGH LIFTS OUT
THEREAFTER...WITH MAIN BAND OF WESTERLIES PUSHING NORTH.
HOWEVER...STOUT UPPER HIGH RETROGRADES ACROSS THE ATLANTIC TOWARDS
THE SOUTHEAST U.S. AFTER SUNDAY. THE SOUTHERLY FLOW INDUCED ACROSS
THE SOUTHERN U.S. WILL PUSH MOISTURE NORTHWARD. THE FIRST SLUG
SHOULD MAINLY STAY OFF TO OUR EAST...KEPT THERE BY AN H500 SHORTWAVE
DROPPING IN FROM THE NORTHWEST. A MORE SIGNIFICANT CHANCE OF RAIN
MAY ARRIVE AREAWIDE BY WEDNESDAY NIGHT/THURSDAY AS A SHEARING UPPER
LOW LIFTS ACROSS THE MISSISSIPPI AND OHIO VALLEYS.
LEFT LINGERING LOW CHANCE POPS IN THE NORTHEAST COUNTIES SUNDAY
EVENING AS THE UPPER LOW DEPART...THEN A DRY INTERLUDE MONDAY/MONDAY
EVENING AS A WEAK SURFACE HIGH MOVES THROUGH. LIMITED POPS TO THE
EASTERN SLOPES WITH THE INITIAL SHOT OF MOISTURE MONDAY NIGHT INTO
TUESDAY MORNING. THEN...DRY AND WARMER WITH ZONAL FLOW. POPS
INCREASE FROM SOUTH TO NORTH WEDNESDAY NIGHT/THURSDAY. HELD OFF ON
THUNDER FOR NOW ALTHOUGH THERE MAY BE A TOUCH OF INSTABILITY.
MEX AND ENSEMBLE TEMPERATURES WERE GENERALLY IN DECENT AGREEMENT AND
DID NOT STRAY FAR.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS
AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z.
MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS
AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS
LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY.
THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT
MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE
CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH
HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS
AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN
SHOWERS EARLY THROUGH AROUND 20Z.
ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR
IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL
ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW
STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY
LIFTING INTO 16Z LATE FRIDAY MORNING.
AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS
DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT.
AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE
EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS
DEVELOPMENT AND DURATION MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M L M L M M M M M M L L
HTS CONSISTENCY M L M M M M M M M M M M
BKW CONSISTENCY H M M M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M H L M
PKB CONSISTENCY M M M M M M M M M M H M
CKB CONSISTENCY M M L L M M M M M M L L
AFTER 18Z FRIDAY...
OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER
SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST
VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/30/LS/CL
NEAR TERM...ARJ
SHORT TERM...30/LS
LONG TERM...CL
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
235 PM EDT THU SEP 27 2012
.SYNOPSIS...
SLOW MOVING FRONT MOVE EAST OF MOUNTAINS FRIDAY MORNING. UPPER
WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE
FRIDAY. DRIER AIR FILTERS IN FROM THE NORTHWEST LATE FRIDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
A QUASI STATIONARY FRONTAL BOUNDARY MEANDERS ACROSS WV TONIGHT.
MODELS SUGGEST IT WILL MOVE EAST OF THE MOUNTAINS BY 12Z FRIDAY.
SYNOPTIC MODELS HAVE NOT HANDLE PCPN WELL TODAY. BASED POPS/WX ON
THE HIGH RESOLUTION MODELS...ESPECIALLY THE HRRR AND THE WRFARW
WHICH BRING SCATTERED SHOWERS ACROSS THE AREA THIS EVENING
DIMINISHING OVERNIGHT WITH NO MENTION OF THUNDER.
MEANTIME...ABUNDANT LOW LEVEL MOISTURE WITH NOT MUCH UPPER LEVEL
SUPPORT SHOULD TRANSLATE INTO WIDESPREAD LOW LEVEL CLOUDS...AND
PERHAPS DENSE FOG OVER HIGHER ELEVATIONS OVERNIGHT. THESE CLOUDS
WILL STAND STRONG THROUGH AT LEAST 13Z BEFORE START TO DISSIPATE
FRIDAY MORNING. THESE FEATURES ARE DEPICTED WITH HIGH CONFIDENCE
BY THE SREF PROBABILITIES...AND NAM/RUC/GFS SOUNDING PROFILES.
A SLIGHTLY DRIER AIRMASS FILTERS IN FROM THE NORTHWEST AS THE H85
FLOW BECOMES NORTHWEST AS SHOWN BY THE CMC/NAM/GFS/ECWF FRIDAY
AFTERNOON...PERHAPS PUSHING EAST THE AFOREMENTIONED CLOUDS...AND
SPREADING CLEARING FROM NORTHWEST TO SOUTHEAST FRIDAY EVENING.
HOWEVER...A WEAK VORT MAX PASSES SOUTH OF THE AREA FRIDAY. KEPT
LIKELY POPS ACROSS THE VIRGINIA COUNTIES FRIDAY AFTERNOON.
WITH PLENTY OF CLOUDS OVERNIGHT...AND JUST A DEGREE CELSIUS LOWER
THAN PREVIOUS NIGHT AT H850...EXPECT NO RADIATIONAL COOLING AND
SLIGHTLY ABOVE NORMAL TEMPERATURES...EXCEPT FOR CRW...GENERALLY
IN THE LOW 60S...RANGING TO THE MID 50S HIGHEST ELEVATIONS.
THEREFORE...WENT WITH THE WARMER NUMBERS BETWEEN THE MET/MAV
GUIDANCE FOR LOWS TONIGHT. HIGH ON FRIDAY WILL DEPEND ON HOW
QUICKLY CLEARING SPREAD EAST SOUTHEAST. THEREFORE...KEEP HIGHER
TEMPS ACROSS SOUTHEAST OH...GENERALLY IN THE MID 70S...RANGING
INTO THE MID 60S HIGHEST ELEVATIONS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
MODELS CONTINUING TO SHOW THE SURFACE FRONT HEADING SOUTH A BIT
FASTER THAN SEVERAL RUNS AGO. NAM IS STILL A LITTLE FASTER...HAVING
THE FRONT TO ATLANTIC COAST BY ABOUT 21Z FRI...WHILE GFS IS CLOSER
TO 00Z SAT. DUE TO THIS...DRIED THINGS UP FASTER...LINGERING ONLY
SLIGHT CHANCE POPS IN EXTREME SOUTHERN WV AND OUR VA COUNTIES
SATURDAY NIGHT AS THE FINAL MOISTURE WITH THIS SYSTEM CLEARS OUT AND
ONE FINAL VORT MAX SLIDES ACROSS TN/NC. ALSO DECREASED SKY COVER A
LITTLE FASTER AS DRY AIR WORKS IN. THE NAM TRIES TO BRING SOME
LOW/MID LEVEL MOISTURE BACK INTO THE MOUNTAINS ON SATURDAY...WHICH
COMBINED WITH FALLING HEIGHTS AS THE NEXT UPPER LEVEL SYSTEM
APPROACHES MAY BE ENOUGH FOR SOME DIURNALLY DRIVEN ISOLATED
MOUNTAINS SHOWERS...HOWEVER GFS/ECMWF CONTINUE BRINGING DRY AIR...SO
OPTED TO LEAVE ANY ISOLATED POPS OUT FOR NOW. MODELS SHOW THAT NEXT
UPPER LOW DROPPING INTO SOUTHEASTERN MICHIGAN BY AROUND 12Z
SUNDAY...WITH MOISTURE FLOW RIGHT OVER THE OHIO RIVER...SO DID BRING
SLIGHT CHANCE POPS INTO NORTHWESTERN CWA BY 06-12Z SUN.
WENT WITH A BLEND OF MAV/MET FOR HIGHS...PROVIDING ONLY SMALL
CHANGES TO PREVIOUS FORECAST. OVERNIGHT LOWS A BIT
TRICKIER...DEPENDING ON HOW FAST CLOUDS CLEAR BEHIND ONE
SYSTEM...AND HOW QUICKLY HIGH CLOUDS MOVE BACK IN AHEAD OF THE NEXT.
BLENDED WITH THE BIAS CORRECTED CONSENSUS GUIDANCE WHICH HAD A GOOD
DEPICTION OF MID 50S ACROSS THE SOUTH FRIDAY NIGHT...WHERE CLOUDS
WILL LINGER LONGEST...THEN CWA-WIDE MID TO UPPER 40S SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MDLS ARE IN REASONABLY GOOD AGREEMENT WITH UPR LOW FCST TO DROP
INTO THE EASTERN LAKES SUN-MON BEFORE LIFTING OUT. HAVE INCLUDED
SOME CHC POPS FOR MAINLY DIURNAL SHRA ACROSS PORTIONS OF SE OH AND
INTO N WV SUN AFTN WITH DRY SLOT KEEPING S AREAS DRY. SFC HIGH
BUILDS IN FOR NEXT WEEK AS THE PATTERN RELAXES AND RIDGING TAKES HOLD
ACROSS S HALF OF THE COUNTRY. SO AFTER INITIALLY COOL TEMPS...A
WARMUP WILL BE NOTED DAYS 6 AND 7 UNDER WAA.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS
AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z.
MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS
AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS
LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY.
THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT
MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE
CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH
HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS
AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN
SHOWERS EARLY THROUGH AROUND 20Z.
ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR
IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL
ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW
STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY
LIFTING INTO 16Z LATE FRIDAY MORNING.
AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS
DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT.
AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE
EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS
DEVELOPMENT AND DURATION MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M L M L M M M M M M L L
HTS CONSISTENCY M L M M M M M M M M M M
BKW CONSISTENCY H M M M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M H L M
PKB CONSISTENCY M M M M M M M M M M H M
CKB CONSISTENCY M M L L M M M M M M L L
AFTER 18Z FRIDAY...
OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER
SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST
VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/30/CL
NEAR TERM...ARJ
SHORT TERM...MZ
LONG TERM...30
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
203 PM EDT THU SEP 27 2012
.SYNOPSIS...
QUASI STATIONARY FRONT FINALLY MOVE EAST OF EASTERN MOUNTAINS
FRIDAY MORNING. UPPER WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON
CONVECTION POSSIBLE. DRIER AIR MAKES INROADS SOUTH ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ADJUSTED POPS CONCENTRATING HIGHER CHANCES ACROSS NORTHERN
PORTIONS OF SOUTHEAST OH AND WV...PER RADAR IMAGES AND LATEST
MODELS OUTPUT. HOWEVER...MODELS INSIST ON BRINGING MORE PCPN
ACROSS THE SOUTHWEST...TO MOVE NORTHEAST ACROSS THE AREA THIS
AFTERNOON AND EVENING. REMOVED THUNDER THROUGH AT LEAST 18Z PER
LACK...DIURNAL HEATING...CAPE AND LOW DEEP LAYERED SHEAR. SOME
STORMS CAN NOT BE RULED OUT THIS AFTERNOON AND EVENING.
PREVIOUS DISCUSSION BELOW...
BUSY GRAVEYARD SHIFT OVERNIGHT. ROUNDS OF SHOWERS/THUNDERSTORMS IN
THE MOISTURE LADEN AIR FOR LATE SEPTEMBER. DEW POINTS AOA 60
DEGREES BECOMING COMMON ACROSS THE LOWLANDS. WITH THE LONGER
NIGHTS...THERE ARE EVEN PATCHES OF FOG DRIFTING ABOUT...BOTH RAIN
INDUCED NORTH...AND RADIATIONAL COOLING INDUCED SOUTH.
THE HEAVIEST RAINS OVERNIGHT SEEMED TO FALL OVER NORTHERN GALLIA
COUNTY INTO NORTHERN MASON AND SOUTHERN MEIGS. HAD SOME MEASURED
AMOUNTS OF 1.6 INCHES SEEN. THAT WAS ONE OF OUR DRIEST AREAS
PREVIOUS TO LAST NIGHT.
WITH PRECIPITABLE WATER REMAINING IN THE 1.5 TO 1.6 INCH RANGE...
WILL CONTINUE TO MONITOR RAIN AMOUNTS OVER PREVIOUSLY AFFECTED
COUNTIES. AS OF 08Z...NO FLASH FLOOD WATCH POSTED.
WAVE DEVELOPING SOUTH OF THE FRONT...BUT FRONT IS SAGGING SOUTH IN
OHIO TO EVENTUALLY COMBINE WITH THE WAVE COMING OUT OF INDIANA NR
08Z. MOST NEAR TERM LOCAL MODELS KEEPING THE MAIN CONVECTION THIS
MORNING IN OHIO. SO HAVE THE HIGHER POPS THAT WERE IN NORTH CENTRAL
WV DURING THIS PREDAWN...LOWERING AS WE HAD FURTHER INTO THE MORE
CIVILIZED HOURS OF THIS MORNING...WITH OUR HIGHER POPS IN SOUTHEAST
OHIO.
AS THE SURFACE WAVE HEADS EAST...WILL FINALLY PUSH THE HIGHER POPS
INTO SOUTHERN WEST VIRGINIA DURING THE 15Z TO 20Z PERIOD. COULD NOT
RULE OUT A FEW MORE STRONG TO SEVERE THUNDERSTORMS AHEAD OF THAT
WAVE IN WEST VIRGINIA DURING THE AFTERNOON.
WAS FASTER IN LOWERING THE CHANCES OF THUNDER LATE TODAY INTO THIS
EVENING...SINCE WE ARE EXPECTING THE WIND SHIFT ASSOCIATED WITH THE
SURFACE WAVE TO BE NEAR THE MASON-DIXON LING OF SW PA AND NRN WV
ABOUND THE 21Z TODAY.
HAVE CONSIDERABLE LOW LEVEL MOISTURE LINGERING THROUGH THE
NIGHT...LINGERING SHOWERS MAY TURN TO DRIZZLE FOR THE WESTERN SLOPES
AND MOUNTAIN COUNTIES...SAY EKN TO CRW TO BKW. HAVE IMPROVING
CONDITIONS OVERNIGHT IN SOUTHEAST OHIO.
TRIED TO HOLD DOWN TEMPERATURES IN THE WEST...BUT THINK AREAS LIKE
EKN TO BKW COULD HAVE TIME TO GO HIGHER THAN SOUTHEAST OHIO.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
MODELS CONTINUING TO SHOW THE SURFACE FRONT HEADING SOUTH A BIT
FASTER THAN SEVERAL RUNS AGO. NAM IS STILL A LITTLE FASTER...HAVING
THE FRONT TO ATLANTIC COAST BY ABOUT 21Z FRI...WHILE GFS IS CLOSER
TO 00Z SAT. DUE TO THIS...DRIED THINGS UP FASTER...LINGERING ONLY
SLIGHT CHANCE POPS IN EXTREME SOUTHERN WV AND OUR VA COUNTIES
SATURDAY NIGHT AS THE FINAL MOISTURE WITH THIS SYSTEM CLEARS OUT AND
ONE FINAL VORT MAX SLIDES ACROSS TN/NC. ALSO DECREASED SKY COVER A
LITTLE FASTER AS DRY AIR WORKS IN. THE NAM TRIES TO BRING SOME
LOW/MID LEVEL MOISTURE BACK INTO THE MOUNTAINS ON SATURDAY...WHICH
COMBINED WITH FALLING HEIGHTS AS THE NEXT UPPER LEVEL SYSTEM
APPROACHES MAY BE ENOUGH FOR SOME DIURNALLY DRIVEN ISOLATED
MOUNTAINS SHOWERS...HOWEVER GFS/ECMWF CONTINUE BRINGING DRY AIR...SO
OPTED TO LEAVE ANY ISOLATED POPS OUT FOR NOW. MODELS SHOW THAT NEXT
UPPER LOW DROPPING INTO SOUTHEASTERN MICHIGAN BY AROUND 12Z
SUNDAY...WITH MOISTURE FLOW RIGHT OVER THE OHIO RIVER...SO DID BRING
SLIGHT CHANCE POPS INTO NORTHWESTERN CWA BY 06-12Z SUN.
WENT WITH A BLEND OF MAV/MET FOR HIGHS...PROVIDING ONLY SMALL
CHANGES TO PREVIOUS FORECAST. OVERNIGHT LOWS A BIT
TRICKIER...DEPENDING ON HOW FAST CLOUDS CLEAR BEHIND ONE
SYSTEM...AND HOW QUICKLY HIGH CLOUDS MOVE BACK IN AHEAD OF THE NEXT.
BLENDED WITH THE BIAS CORRECTED CONSENSUS GUIDANCE WHICH HAD A GOOD
DEPICTION OF MID 50S ACROSS THE SOUTH FRIDAY NIGHT...WHERE CLOUDS
WILL LINGER LONGEST...THEN CWA-WIDE MID TO UPPER 40S SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MDLS ARE IN REASONABLY GOOD AGREEMENT WITH UPR LOW FCST TO DROP
INTO THE EASTERN LAKES SUN-MON BEFORE LIFTING OUT. HAVE INCLUDED
SOME CHC POPS FOR MAINLY DIURNAL SHRA ACROSS PORTIONS OF SE OH AND
INTO N WV SUN AFTN WITH DRY SLOT KEEPING S AREAS DRY. SFC HIGH
BUILDS IN FOR NEXT WEEK AS THE PATTERN RELAXES AND RIDGING TAKES HOLD
ACROSS S HALF OF THE COUNTRY. SO AFTER INITIALLY COOL TEMPS...A
WARMUP WILL BE NOTED DAYS 6 AND 7 UNDER WAA.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS
AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z.
MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS
AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS
LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY.
THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT
MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE
CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH
HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS
AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN
SHOWERS EARLY THROUGH AROUND 20Z.
ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR
IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL
ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW
STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY
LIFTING INTO 16Z LATE FRIDAY MORNING.
AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS
DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT.
AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE
EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS
DEVELOPMENT AND DURATION MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M L M L M M M M M M L L
HTS CONSISTENCY M L M M M M M M M M M M
BKW CONSISTENCY H M M M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M H L M
PKB CONSISTENCY M M M M M M M M M M H M
CKB CONSISTENCY M M L L M M M M M M L L
AFTER 18Z FRIDAY...
OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER
SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST
VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/ARJ
SHORT TERM...MZ
LONG TERM...30
AVIATION...ARJ
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1246 PM CDT THU SEP 27 2012
.UPDATE...
UPDATED FOR AVIATION.
&&
.PREV DISCUSSION... /ISSUED 622 AM CDT THU SEP 27 2012/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 231 AM CDT THU SEP 27 2012/
DISCUSSION...
A STALLED FRONT REMAINS LOCATED ACROSS SOUTHERN MISSOURI THIS
MORNING. SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG
THE BOUNDARY. LATEST HRRR MODEL INDICATES THESE SHOWERS AND
THUNDERSTORMS WILL BEGIN MOVING SOUTHEAST INTO THE CWA. LOOKING AT
LATEST RADAR IMAGES...BEGINNING TO SEE INDIVIDUAL STORMS MOVING TO
THE SOUTHEAST. AS A RESULT...WILL CONTINUE WITH LIKELY POPS ACROSS
NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND NORTHWEST
TENNESSEE INTO THE MORNING HOURS. HRRR SHOWS ACTIVITY DYING OUT
BY NOON TIME. DURING THE AFTERNOON...REDEVELOPMENT WILL LIKELY
OCCUR ACROSS SOUTHERN MISSOURI NEAR THE FRONT. SOME OF THE
ACTIVITY COULD SKIRT NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL
AND EXTREME NORTHWEST TENNESSEE. WILL GO WITH 40 POPS IN THE
AFTERNOON FOR THESE AREAS. ELSEWHERE...CONDITIONS SHOULD STAY DRY.
ALTHOUGH...MAY SEE MOSTLY CLOUDY CONDITIONS MAINLY FROM BLOW OFF
FROM CONVECTION OCCURRING TO THE NORTH OR WEST. HIGHS WILL BE IN
THE 80S.
TONIGHT...EXPECT WHATEVER ACTIVITY THAT DEVELOPS THIS AFTERNOON
ACROSS SOUTHERN MISSOURI TO BEGIN SPREADING SOUTHWARD INTO THE CWA
AS MODELS INDICATE FRONT MAY START MOVING TO THE SOUTH. BEST CHANCES
WILL OCCUR ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND
WEST TENNESSEE. LOWS WILL BE IN THE 60S.
FRIDAY AND FRIDAY NIGHT...FRONT PUSHES INTO THE CWA THUS EXPECT
CHANCES FOR SHOWERS AND THUNDERSTORMS TO SPREAD ACROSS THE ENTIRE
CWA. HOWEVER...EXPECT RAINFALL AMOUNTS TO REMAIN ON THE LIGHT SIDE.
THE WEEKEND...BY SATURDAY MORNING...COOLER AND DRIER AIR WILL BEGIN
SPREADING INTO PORTIONS OF NORTHWEST TENNESSEE. EXPECT FRONT TO
LIKELY BE LOCATED JUST TO THE SOUTH OF THE CWA. HOWEVER STILL EXPECT
SOME POST FRONTAL RAIN TO OCCUR MAINLY OVER NORTH MISSISSIPPI AND
EAST CENTRAL ARKANSAS. BY SATURDAY NIGHT INTO SUNDAY...EXPECT COOLER
AND DRIER AIR TO HAVE FILTERED INTO MUCH OF THE CWA WITH ONLY
EXTREME SOUTHERN PORTIONS OF THE CWA SEEING CONTINUING CHANCES FOR
RAIN.
MONDAY THROUGH WEDNESDAY...A BROAD UPPER TROF WILL REMAIN OVER THE
MIDSOUTH. MODELS KEEP FLIPPING BACK AND FORTH ON WHETHER A CLOSED
UPPER LOW FORMS. A SFC LOW IS EXPECTED TO DEVELOP ALONG THE GULF
COAST. DEPENDING ON THE LOCATION OF THE LOW...SOME RAIN COULD SPREAD
NORTHWARD INTO NORTHEAST MISSISSIPPI AS IT PUSHES EAST. FOR NOW WILL
CONTINUE WITH DRY FORECAST UNTIL MODELS SHOW SOME CONSISTENCY.
KRM
&&
.AVIATION...
18Z TAFS
A SURFACE COLD FRONT OVER SOUTHERN IL TO JUST SOUTH OF STL AT
MIDDAY WILL SETTLE INTO THE MIDSOUTH TOWARD LATE AFTERNOON. NAM AND
HRRR MODELS ARE CONSISTENT IN DEVELOPING SCATTERED SHRA/TSRA ALONG
AND BEHIND THE FRONT. SLIGHT TO MODERATE LOW LEVEL INSTABILITY
WILL BE SUPPORTIVE OF TSRA THROUGH 00Z...BUT FRONTAL PUSH WILL BE
WEAK. WITH LOWER SUN ANGLES DURING THE LATE AFTERNOON...TSRA
COVERAGE SHOULD BE LIMITED. HAVE INCLUDED A BRIEF VCTS AT MEM AT
22Z. CONFIDENCE IS NOT SUFFICIENT TO WARRANT A TEMPO FOR THE
SCHEDULED 18Z TAFS.
VFR AND LIGHT /LESS THAN 5KT/ SURFACE WINDS LATE THIS EVENING AND
EARLY OVERNIGHT AT MEM.
PWB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 84 69 83 65 / 20 30 50 30
MKL 83 63 81 59 / 30 40 60 20
JBR 82 64 79 59 / 60 60 60 40
TUP 86 66 86 63 / 10 10 40 30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1241 PM CDT THU SEP 27 2012
.UPDATE...FOR 18Z AVIATION FORECAST
&&
.AVIATION...
AIR MASS ACROSS THE TENNESSEE VALLEY IS FAIRLY DEEP IN MOISTURE TO
ABOUT 25K FEET THROUGH 12Z SATURDAY. EVEN THOUGH FRONTAL BOUNDARY
IS LAYING JUST TO OUR NORTH SEEMS LIKE SHOWERS THAT MOVED IN FROM
THE WEST EARLIER THIS MORNING WERE TIED MORE TO ONE OF THE WEAK MID
LEVEL DISTURBANCES THAT HAS BEEN TRANSIENT IN THE WEST TO EAST
FLOW ALOFT FROM OKLAHOMA TO TENNESSEE. BASICALLY LOOKING FOR VFR
CONDITIONS THROUGH ABOUT 08Z TONIGHT THEN GOING DOWNHILL RATHER
QUICKLY DUE TO LOW CEILINGS AND FOG. SHOULD RETURN TO VFR BY 15Z.
BOYD
&&
.PREV DISCUSSION... /ISSUED 946 AM CDT THU SEP 27 2012/
UPDATE...
RADAR IMAGERY THIS MORNING SHOWS AN AREA OF SHOWERS AND
THUNDERSTORMS EXTENDING FROM WESTERN KY TO JUST NORTH OF MEM
MOVING EASTWARD. LATEST HRRR RUNS SEEM TO HAVE A DECENT HANDLE ON
THIS ACTIVITY AND BRING IT ACROSS NORTHERN ZONES THROUGH THE REST
OF THE MORNING INTO THE AFTERNOON HOURS. ADDITIONAL BUT MORE
ISOLATED TO WIDELY SCATTERED SHOWERS AND MAYBE A STORM OR TWO
ALSO WILL LIKELY FORM TO THE SOUTH OF THIS ONGOING ACTIVITY AS
WELL. BASED ON THIS REASONING...HAVE KEPT THE INHERITED POPS
GENERALLY IN PLACE WITH SOME ADJUSTMENTS...SHOWING CATEGORICAL
POPS OVER THE NORTHWEST ZONES DIMINISHING TO SLIGHT/NO CHANCE
ALONG THE ALABAMA BORDER. CLOUD COVER ALSO ADJUSTED GENERALLY
UPWARD WHILE HIGH TEMPS WERE NUDGED DOWN OVER THE NORTHERN HALF.
REST OF FORECAST WAS LEFT UNCHANGED AT THIS TIME.
PREV DISCUSSION... /ISSUED 708 AM CDT THU SEP 27 2012/
AVIATION 12Z DISCUSSION...
COLD FRONT TO THE NORTH OF TN THIS MORNING WILL MOVE SOUTHWARD AND
WILL BE LOCATED IN CLOSE PROXIMITY OF THE TAF AREAS ON FRIDAY
MORNING. ELEVATED INSTABILITY LEVELS WILL ALLOW FOR SOME ISOL TSTM
DEVELOPMENT THIS AFTERNOON. THEN AS THE FRONT SINKS SOUTHWARD...ISOL
TO SCT SHOWER ACTIVITY WILL CONTINUE OVERNIGHT. IFR CONDITIONS
WILL OCCUR BETWEEN 06Z AND 12Z AS CIGS AND VSBYS LOWER.
PREV DISCUSSION... /ISSUED 426 AM CDT THU SEP 27 2012/
DISCUSSION...
CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN
ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST
ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND
HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE
TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE
I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT
MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED
ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE
COLD FRONT BEGINS TO MOVE SOUTH.
THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND
INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS
INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE
INHIBITION.
THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND
SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY
SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO
THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S.
MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO
VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES
ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME
THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE
MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI
VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER
CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO
BE AROUND NORMAL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
224 PM EDT THU SEP 27 2012
.SYNOPSIS...
A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY
SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL
TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED
STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EDT WEDNESDAY...
THE EARLY MORNING FORECAST PACKAGE APPEARS TO BE IN GOOD SHAPE...
WITH THE OBSERVED HOURLY TEMPERATURE INCREASES ON TRACK TO BE VERY
CLOSE TO EXPECTED AFTERNOON HIGHS. DID ADJUST THE AREA OF CLOUD
COVER IN THE FORECAST TO BETTER REFLECT LATEST VISIBLE SATELLITE
IMAGERY. STARTING TO SEE A FEW RETURNS ON RADAR OVER CENTRAL WEST
VIRGINIA...WHICH ARE EXPECTED TO APPROACH OUR WESTERN RIDGELINES
BY NOON...SO WILL CONTINUE TO MONITOR THE DEVELOPMENT OF THIS
ACTIVITY.
AS OF 420 AM EDT WEDNESDAY...
THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA.
MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE
ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE
FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS
OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT
LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION
INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z.
OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE
SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE
WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE
MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN
BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT.
TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING.
WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE
NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS
THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO
LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 340 AM EDT THURSDAY...
MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST
MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY
AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ.
MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO
SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA
DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND
EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE
ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE
VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING.
CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN
THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE
AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY
NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH
AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST.
RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES
COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL.
LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH
TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING
OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY
WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 245 PM EDT WEDNESDAY...
FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH
OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND
EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE
ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO
DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE
TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION.
THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY
NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH
THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL
APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK
THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE
GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL
TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN
EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE
OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH
SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM EDT THURSDAY...
ALL LOCATIONS ARE REPORTING VFR CONDITIONS THIS AFTERNOON...
CONDITIONS WHICH ARE EXPECTED TO CONTINUE THROUGH THE REMAINDER OF
THURSDAY OUTSIDE OF SHOWER AND ISOLATED THUNDERSTORM ACTIVITY.
LATEST ROUND OF SHORT RANGE MODELS INDICATE THAT A WEAK LOW
PRESSURE SYSTEM WILL RIDE ALONG THE FRONTAL BOUNDARY TO OUR
NORTH...TRIGGERING A ROUND OF SHOWERS AND THUNDERSTORMS THAT WILL
PASS ACROSS KENTUCKY INTO WESTERN VIRGINIA THIS EVENING. MUCH OF THIS
ACTIVITY WILL DIE OFF AS IT PASSES THE RIDGELINES ALONG THE
WESTERN BORDER OF THE FORECAST AREA...ENTERING INTO DOWNSLOPE
FLOW...BUT A FEW WILL SURVIVE LONG ENOUGH TO AFFECT BLF...LWB AND
BCB. MODELS ALSO INDICATE THE POSSIBILITY OF A THUNDERSTORM OR TWO
DEVELOPING JUST EAST OF THE BLUE RIDGE AS A WEAK DISTURBANCE ALOFT
INTERACTS WITH THE LEE SIDE TROUGH SITUATED OVER THE AREA...ALTHOUGH
INSTABILITY WILL BE MODEST AT BEST.
CIRRUS WILL REMAIN WIDESPREAD ACROSS THE MOUNTAINS OVERNIGHT...
HOWEVER WITH LIGHT SOUTHWESTERLY TO WESTERLY WINDS CARRYING WARM
MOIST AIR INTO THE AREA...STILL EXPECT TO SEE ANOTHER ROUND OF PATCHY
DENSE FOG DEVELOP...ESPECIALLY AT LWB AND BCB...WHICH COULD FALL
TO A QUARTER MILE OR LESS. VISIBILITIES WILL IMPROVE QUICKLY AFTER
28/13Z AS DAYTIME HEATING INCREASES.
BY MID FRIDAY MORNING...THE LOW PRESSURE SYSTEM WILL PROGRESS EAST
INTO THE LOWER NEW ENGLAND STATES...DRAGGING THE COLD FRONT
FURTHER SOUTH ACROSS OUR AREA. ADDITIONAL SHOWER AND ISOLATED
THUNDERSTORM ACTIVITY WILL DEVELOP ACROSS OUR AREA AS THE FRONT
PASSES THROUGH...WITH LOCALLY MVFR CONDITIONS DEVELOPING IN THIS
ACTIVITY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/JH
NEAR TERM...AMS/NF
SHORT TERM...RCS
LONG TERM...WP
AVIATION...AMS/NF