Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/04/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1113 PM MDT THU OCT 3 2013
.UPDATE...
ISSUED AT 1107 PM MDT THU OCT 3 2013
ADDED FOG TO PARTS OF THE PLAINS TONIGHT...MAINLY ALONG AND NORTH
OF THE ARKANSAS RIVER. ALSO...LOADED FRESH OBSERVATIONS INTO THE
FRONT END OF THE FORECAST GRIDS.
UPDATE ISSUED AT 603 PM MDT THU OCT 3 2013
LOADED CURRENT OBSERVATIONS INTO FRONT END OF FORECAST GRIDS AND
BLENDED INTO REST OF FORECAST. NO OTHER CHANGES AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 240 PM MDT THU OCT 3 2013
CURRENTLY...
SFC BOUNDARY EXTENDS FROM NEAR CANON CITY...SOUTHEASTWARD TOWARDS
KSPD. BOUNDARY BEST DEFINED BY DWPTS AS S OF BOUNDARY DWPTS WERE IN
THE 20S WHILE N OF THE BOUNDARY DWPTS WERE IN THE U30S/40S. LOTS OF
LOW CLOUDS WERE NOTED OVER FAR NE CO/NW KS. CLOUDS WERE INCREASING
OVER THE C MTNS. KGJT 88D NOTED SHOWERS WERE INCREASING OVER NW CO
INTO E UTAH.
ON THE LARGE SCALE...A BROAD 50 MB LOW WAS LOCATED OVER IDAHO AND
WAS DROPPING EAST-SOUTHEAST.
REST OF TODAY INTO TONIGHT...
MAIN CONCERN TONIGHT WILL BE OVER THE C MTNS. THIS REGION WILL
LIKELY SEE PRECIP INCREASING EARLY THIS EVENING AND THIS PRECIP WILL
INTENSIFY AS THE EVENING PROGRESSES. WITH STRONG FORCING MOVING
ACROSS THE REGION AND STRONG UPSLOPE OVER THE CONTDVD...SNOW WILL
BECOME HEAVY FOR A PD OF TIME TONIGHT. SEVERAL INCHES OF SNOW WILL BE
LIKELY.
THE NEXT CONCERN IS LOW CLOUDS OVER THE PLAINS. SFC FLOW WILL LIKELY
NOT CHANGE TOO MUCH FROM CURRENT REGIME. HRRR SHOWS HI RH AT SFC
MOVING BACK TOWARDS THE MTNS WHILE OTHER GUIDANCE HAS QUITE A BIT OF
DRY AIR JUST ABOVE THE SFC....AND THESE GUIDANCE PRODUCTS KEEP THE
PLAINS CLEAR. WILL LIKELY WAIT TIL THE LAST MINUTE TO LOOK AT LATEST
GUIDANCE TO DECIDE IF LOW CLOUDS WILL BE NEEDED OVER THE PLAINS.
BY LATE TONIGHT...FORCING WILL BE MOVING EASTWARD AND SHOWER MAY
START TO AFFECT THE PIKES PEAK REGION. PRECIP WILL BE SNOW AT HIGHER
ELEVATIONS WITH RAIN SHOWERS AT LOWER ELEVATIONS
EXCEPT FOR AREAS DISCUSSED ABOVE...THE REST OF THE REGION WILL
REMAIN DRY.
TOMORROW...
STRONG COLD FRONT WILL BLAST DOWN THE PLAINS. FRONT WILL BE UP ALONG
THE PALMER DIVIDE AT SUNRISE AND WILL QUICKLY BLAST SOUTHEAST DURING
THE REST OF THE MORNING. WINDS WILL PICK UP AND BECOME GUSTY FROM
THE NORTHWEST AS THE MORNING PROGRESSES. I ANTICIPATE WINDS WILL BE
IN THE G40 TO 45 MPH RANGE...MAINLY EAST OF A LINE FROM E EL PASO
COUNTY TO EASTERN LAS ANIMAS COUNTY. WINDS WILL ALSO BE GUSTY
ELSEWHERE....ESPECIALLY OVER THE MTNS. TEMPERATURES TOMORROW WILL
NOT RISE TOO MUCH...IF AT ALL. TEMPS IN THE 80S TODAY WILL ONLY
REACH INTO THE 40S AND 50S TOMORROW...WITH SOME 60S POSSIBLE EARLY
ACROSS THE FAR SE PLAINS. THE WARMEST TEMPS WILL OCCUR MAINLY IN THE
MORNING HOURS.
SHOWERS WILL CONTINUE ACROSS THE C MTNS AND SW MTNS TOMORROW...AND
POSSIBLY ACROSS THE HIGHER ELEVATIONS OF THE S MTNS AND PALMER DVD.
SHOWERS OVER THE REGION WILL BE ENHANCED BY A SECONDARY PIECE OF
ENERGY WRAPPING AROUND THE UPPER LOW COMING ACROSS THE REGION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 240 PM MDT THU OCT 3 2013
FRIDAY NIGHT...NAM...GFS AND EC MODELS PLACE THE UPPER LOW OVER THE
NE CORNER OF THE STATE AT 00Z SAT...AND THEN QUICKLY MOVING THE
SYSTEM OFF TO THE E-NE THROUGH THE NIGHT. STRONG GUSTY NORTH WINDS
ARE FORECAST TO CONTINUE THROUGH THE EARLY EVENING FOR THE E PLAINS
AS WRAPAROUND FROM THE DEPARTING SYSTEM DRAWS A STRONG COLD POOL
DOWN INTO THE CWA. MODELS ARE NOT SHOWING A LOT OF PCPN WITH THIS
SYSTEM...SO THE MAIN STORY WILL BE INITIALLY THE STRONG WINDS BUT
THEN THE SIGNIFICANTLY COLDER AIR OVERNIGHT INTO EARLY SAT MORNING.
THIS PROMPTED A FREEZE WATCH ISSUANCE EARLIER TODAY...IN EFFECT FROM
MIDNIGHT FRI THROUGH 9 AM SAT MORN...FOR THE I-25 CORRIDOR AS WELL
AS CROWLEY AND OTERO COUNTIES. THE MAIN AREA THOUGH MOST LIKELY WILL
BE ALONG THE I-25 CORRIDOR AND NEAR THE MTS WHERE THE COLD AIR WILL
POOL AND DROP MIN TEMPS DOWN INTO THE MID TO UPPER 20S.
SATURDAY THROUGH TUESDAY...THE UPPER SYSTEM QUICKLY EXITS TO THE
E-NE SAT MORNING...THEN MODELS INDICATE THAT AN UPPER RIDGE OF HIGH
PRESSURE WILL SLOWLY SLIDE EASTWARD ACROSS THE WESTERN HALF OF THE
COUNTRY THROUGH TUESDAY. LOOK FOR DRY CONDITIONS AND GRADUALLY
WARMING TEMPS OVER THE WEEKEND AND INTO THE BEGINNING OF THE NEXT
WORK WEEK. EXPECT 50S AND 60S ON SAT...60S AND 70S SUN...THEN 70S TO
AROUND 80 F BOTH MON AND TUE. THERE IS THE OUTSIDE CHANCE THAT SAT
NIGHT/SUN MORN WILL SEE ANOTHER FREEZE FOR THE EASTERN PLAINS DUE
TO CLEAR SKIES AND LINGERING COLD AIR.
WEDNESDAY AND THURSDAY...EC AND GFS MODELS INDICATE THAT ANOTHER
UPPER TROUGH WILL DROP DOWN ACROSS THE GREAT BASIN BY
MID-WEEK...BRINGING WARM AND DRY CONDITIONS DUE TO SW FLOW ON WED.
BY WED NIGHT SHOWERS WILL RETURN TO THE CONTDVD...WITH COOLER TEMPS
AND A BETTER CHANCE FOR PCPN FOR ALL OF THE CWA ON THU. MOORE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1107 PM MDT THU OCT 3 2013
MAIN CONCERN AT ALL 3 TAF SITES WILL BE GUSTY WINDS NEXT 24H. A
STRONG COLD FRONT WILL CROSS KPUB AND KCOS TOMORROW MORNING AROUND
SUNRISE AND GUSTY NORTHWEST WINDS WILL DEVELOP TOMORROW MORNING INTO
TOMORROW AFTERNOON. NORTHWEST WINDS TO 15 TO 30+ KNTS WILL BE
POSSIBLE. GUSTY SOUTHWEST WINDS WILL ALSO OCCUR AT KALS SHIFTING TO
WNW LATER TOMORROW AFTERNOON. KALS SHOULD SEE VFR THROUGH THE PD.
FOR KCOS AND KPUB...THERE IS A LOW CHANCE THAT WE MAY SEE SOME LOW
CIGS LATER TONIGHT. SOME MEMBERS OF THE SREF ALONG WITH HRRR
GUIDANCE SHOW SOME LOW CIGS POSSIBLE...HOWEVER THE LARGE MAJORITY OF
THE GUIDANCE KEEPS LOW CIGS AWAY FROM KPUB AND KALS.
THERE MAY BE A FEW SHOWERS AT KCOS TOMORROW...BUT BRUNT OF PRECIP
SHOULD REMAIN NORTH ALONG THE PALMER DVD.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR
COZ083>089-093.
&&
$$
UPDATE...LW
SHORT TERM...HODANISH
LONG TERM...MOORE
AVIATION...LW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
605 PM MDT THU OCT 3 2013
.UPDATE...
ISSUED AT 603 PM MDT THU OCT 3 2013
LOADED CURRENT OBSERVATIONS INTO FRONT END OF FORECAST GRIDS AND
BLENDED INTO REST OF FORECAST. NO OTHER CHANGES AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 240 PM MDT THU OCT 3 2013
CURRENTLY...
SFC BOUNDARY EXTENDS FROM NEAR CANON CITY...SOUTHEASTWARD TOWARDS
KSPD. BOUNDARY BEST DEFINED BY DWPTS AS S OF BOUNDARY DWPTS WERE IN
THE 20S WHILE N OF THE BOUNDARY DWPTS WERE IN THE U30S/40S. LOTS OF
LOW CLOUDS WERE NOTED OVER FAR NE CO/NW KS. CLOUDS WERE INCREASING
OVER THE C MTNS. KGJT 88D NOTED SHOWERS WERE INCREASING OVER NW CO
INTO E UTAH.
ON THE LARGE SCALE...A BROAD 50 MB LOW WAS LOCATED OVER IDAHO AND
WAS DROPPING EAST-SOUTHEAST.
REST OF TODAY INTO TONIGHT...
MAIN CONCERN TONIGHT WILL BE OVER THE C MTNS. THIS REGION WILL
LIKELY SEE PRECIP INCREASING EARLY THIS EVENING AND THIS PRECIP WILL
INTENSIFY AS THE EVENING PROGRESSES. WITH STRONG FORCING MOVING
ACROSS THE REGION AND STRONG UPSLOPE OVER THE CONTDVD...SNOW WILL
BECOME HEAVY FOR A PD OF TIME TONITE. SEVERAL INCHES OF SNOW WILL BE
LIKELY.
THE NEXT CONCERN IS LOW CLOUDS OVER THE PLAINS. SFC FLOW WILL LIKELY
NOT CHANGE TOO MUCH FROM CURRENT REGIME. HRRR SHOWS HI RH AT SFC
MOVING BACK TOWARDS THE MTNS WHILE OTHER GUIDANCE HAS QUITE A BIT OF
DRY AIR JUST ABOVE THE SFC....AND THESE GUIDANCE PRODUCTS KEEP THE
PLAINS CLEAR. WILL LIKELY WAIT TIL THE LAST MINUTE TO LOOK AT LATEST
GUIDANCE TO DECIDE IF LOW CLOUDS WILL BE NEEDED OVER THE PLAINS.
BY LATE TONIGHT...FORCING WILL BE MOVING EASTWARD AND SHOWER MAY
START TO AFFECT THE PIKES PEAK REGION. PRECIP WILL BE SNOW AT HIGHER
ELEVATIONS WITH RAIN SHOWERS AT LOWER ELEVATIONS
EXCEPT FOR AREAS DISCUSSED ABOVE...THE REST OF THE REGION WILL
REMAIN DRY.
TOMORROW...
STRONG COLD FRONT WILL BLAST DOWN THE PLAINS. FRONT WILL BE UP ALONG
THE PALMER DIVIDE AT SUNRISE AND WILL QUICKLY BLAST SOUTHEAST DURING
THE REST OF THE MORNING. WINDS WILL PICK UP AND BECOME GUSTY FROM
THE NORTHWEST AS THE MORNING PROGRESSES. I ANTICIPATE WINDS WILL BE
IN THE G40 TO 45 MPH RANGE...MAINLY EAST OF A LINE FROM E EL PASO
COUNTY TO EASTERN LAS ANIMAS COUNTY. WINDS WILL ALSO BE GUSTY
ELSEWHERE....ESPECIALLY OVER THE MTNS. TEMPERATURES TOMORROW WILL
NOT RISE TOO MUCH...IF AT ALL. TEMPS IN THE 80S TODAY WILL ONLY
REACH INTO THE 40S AND 50S TOMORROW...WITH SOME 60S POSSIBLE EARLY
ACROSS THE FAR SE PLAINS. THE WARMEST TEMPS WILL OCCUR MAINLY IN THE
MORNING HOURS.
SHOWERS WILL CONTINUE ACROSS THE C MTNS AND SW MTNS TOMORROW...AND
POSSIBLY ACROSS THE HIGHER ELEVATIONS OF THE S MTNS AND PALMER DVD.
SHOWERS OVER THE REGION WILL BE ENHANCED BY A 2NDRY PIECE OF ENERGY
WRAPPING AROUND THE UPPER LOW COMING ACROSS THE REGION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 240 PM MDT THU OCT 3 2013
FRIDAY NIGHT...NAM...GFS AND EC MODELS PLACE THE UPPER LOW OVER THE
NE CORNER OF THE STATE AT 00Z SAT...AND THEN QUICKLY MOVING THE
SYSTEM OFF TO THE E-NE THROUGH THE NIGHT. STRONG GUSTY NORTH WINDS
ARE FORECAST TO CONTINUE THROUGH THE EARLY EVENING FOR THE E PLAINS
AS WRAPAROUND FROM THE DEPARTING SYSTEM DRAWS A STRONG COLD POOL
DOWN INTO THE CWA. MODELS ARE NOT SHOWING A LOT OF PCPN WITH THIS
SYSTEM...SO THE MAIN STORY WILL BE INITIALLY THE STRONG WINDS BUT
THEN THE SIGNIFICANTLY COLDER AIR OVERNIGHT INTO EARLY SAT MORNING.
THIS PROMPTED A FREEZE WATCH ISSUANCE EARLIER TODAY...IN EFFECT FROM
MIDNIGHT FRI THROUGH 9 AM SAT MORN...FOR THE I-25 CORRIDOR AS WELL
AS CROWLEY AND OTERO COUNTIES. THE MAIN AREA THOUGH MOST LIKELY WILL
BE ALONG THE I-25 CORRIDOR AND NEAR THE MTS WHERE THE COLD AIR WILL
POOL AND DROP MIN TEMPS DOWN INTO THE MID TO UPPER 20S.
SATURDAY THROUGH TUESDAY...THE UPPER SYSTEM QUICKLY EXITS TO THE
E-NE SAT MORNING...THEN MODELS INDICATE THAT AN UPPER RIDGE OF HIGH
PRESSURE WILL SLOWLY SLIDE EASTWARD ACROSS THE WESTERN HALF OF THE
COUNTRY THROUGH TUESDAY. LOOK FOR DRY CONDITIONS AND GRADUALLY
WARMING TEMPS OVER THE WEEKEND AND INTO THE BEGINNING OF THE NEXT
WORK WEEK. EXPECT 50S AND 60S ON SAT...60S AND 70S SUN...THEN 70S TO
AROUND 80 F BOTH MON AND TUE. THERE IS THE OUTSIDE CHANCE THAT SAT
NIGHT/SUN MORN WILL SEE ANOTHER FREEZE FOR THE EASTERN PLAINS DUE
TO CLEAR SKIES AND LINGERING COLD AIR.
WEDNESDAY AND THURSDAY...EC AND GFS MODELS INDICATE THAT ANOTHER
UPPER TROUGH WILL DROP DOWN ACROSS THE GREAT BSAIN BY
MID-WEEK...BRINGING WARM AND DRY CONDITIONS DUE TO SW FLOW ON WED.
BY WED NIGHT SHOWERS WILL RETURN TO THE CONTDVD...WITH COOLER TEMPS
AND A BETTER CHANCE FOR PCPN FOR ALL OF THE CWA ON THU. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 240 PM MDT THU OCT 3 2013
MAIN CONCERN AT ALL 3 TAF SITES WILL BE GUSTY WINDS NEXT 24H. A
STRONG COLD FRONT WILL CROSS KPUB AND KCOS TOMORROW MORNING AROUND
SUNRISE AND GUSTY NORTHWEST WINDS WILL DEVELOP TOMORROW MORNING INTO
TOMORROW AFTERNOON. NORTHWEST WINDS TO 15 TO 30+ KNTS WILL BE
POSSIBLE. GUSTY SOUTHWEST WINDS WILL ALSO OCCUR AT KALS SHIFTING TO
WNW LATER TOMORROW AFTERNOON. KALS SHOULD SEE VFR THROUGH THE PD.
FOR KCOS AND KPUB...THERE IS A LOW CHANCE THAT WE MAY SEE SOME LOW
CIGS LATER TONIGHT. SOME MEMBERS OF THE SREF ALONG WITH HRRR
GUIDANCE SHOW SOME LOW CIGS POSSIBLE...HOWEVER THE LARGE MAJORITY OF
THE GUIDANCE KEEPS LOW CIGS AWAY FROM KPUB AND KALS.
THERE MAY BE A FEW SHOWERS AT KCOS TOMORROW...BUT BRUNT OF PRECIP
SHOULD REMAIN NORTH ALONG THE PALMER DVD.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR
COZ083>089-093.
&&
$$
UPDATE...LW
SHORT TERM...HODANISH
LONG TERM...MOORE
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
311 PM MDT THU OCT 3 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 240 PM MDT THU OCT 3 2013
CURRENTLY...
SFC BOUNDARY EXTENDS FROM NEAR CANON CITY...SOUTHEASTWARD TOWARDS
KSPD. BOUNDARY BEST DEFINED BY DWPTS AS S OF BOUNDARY DWPTS WERE IN
THE 20S WHILE N OF THE BOUNDARY DWPTS WERE IN THE U30S/40S. LOTS OF
LOW CLOUDS WERE NOTED OVER FAR NE CO/NW KS. CLOUDS WERE INCREASING
OVER THE C MTNS. KGJT 88D NOTED SHOWERS WERE INCREASING OVER NW CO
INTO E UTAH.
ON THE LARGE SCALE...A BROAD 50 MB LOW WAS LOCATED OVER IDAHO AND
WAS DROPPING EAST-SOUTHEAST.
REST OF TODAY INTO TONIGHT...
MAIN CONCERN TONIGHT WILL BE OVER THE C MTNS. THIS REGION WILL
LIKELY SEE PRECIP INCREASING EARLY THIS EVENING AND THIS PRECIP WILL
INTENSIFY AS THE EVENING PROGRESSES. WITH STRONG FORCING MOVING
ACROSS THE REGION AND STRONG UPSLOPE OVER THE CONTDVD...SNOW WILL
BECOME HEAVY FOR A PD OF TIME TONITE. SEVERAL INCHES OF SNOW WILL BE
LIKELY.
THE NEXT CONCERN IS LOW CLOUDS OVER THE PLAINS. SFC FLOW WILL LIKELY
NOT CHANGE TOO MUCH FROM CURRENT REGIME. HRRR SHOWS HI RH AT SFC
MOVING BACK TOWARDS THE MTNS WHILE OTHER GUIDANCE HAS QUITE A BIT OF
DRY AIR JUST ABOVE THE SFC....AND THESE GUIDANCE PRODUCTS KEEP THE
PLAINS CLEAR. WILL LIKELY WAIT TIL THE LAST MINUTE TO LOOK AT LATEST
GUIDANCE TO DECIDE IF LOW CLOUDS WILL BE NEEDED OVER THE PLAINS.
BY LATE TONIGHT...FORCING WILL BE MOVING EASTWARD AND SHOWER MAY
START TO AFFECT THE PIKES PEAK REGION. PRECIP WILL BE SNOW AT HIGHER
ELEVATIONS WITH RAIN SHOWERS AT LOWER ELEVATIONS
EXCEPT FOR AREAS DISCUSSED ABOVE...THE REST OF THE REGION WILL
REMAIN DRY.
TOMORROW...
STRONG COLD FRONT WILL BLAST DOWN THE PLAINS. FRONT WILL BE UP ALONG
THE PALMER DIVIDE AT SUNRISE AND WILL QUICKLY BLAST SOUTHEAST DURING
THE REST OF THE MORNING. WINDS WILL PICK UP AND BECOME GUSTY FROM
THE NORTHWEST AS THE MORNING PROGRESSES. I ANTICIPATE WINDS WILL BE
IN THE G40 TO 45 MPH RANGE...MAINLY EAST OF A LINE FROM E EL PASO
COUNTY TO EASTERN LAS ANIMAS COUNTY. WINDS WILL ALSO BE GUSTY
ELSEWHERE....ESPECIALLY OVER THE MTNS. TEMPERATURES TOMORROW WILL
NOT RISE TOO MUCH...IF AT ALL. TEMPS IN THE 80S TODAY WILL ONLY
REACH INTO THE 40S AND 50S TOMORROW...WITH SOME 60S POSSIBLE EARLY
ACROSS THE FAR SE PLAINS. THE WARMEST TEMPS WILL OCCUR MAINLY IN THE
MORNING HOURS.
SHOWERS WILL CONTINUE ACROSS THE C MTNS AND SW MTNS TOMORROW...AND
POSSIBLY ACROSS THE HIGHER ELEVATIONS OF THE S MTNS AND PALMER DVD.
SHOWERS OVER THE REGION WILL BE ENHANCED BY A 2NDRY PIECE OF ENERGY
WRAPPING AROUND THE UPPER LOW COMING ACROSS THE REGION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 240 PM MDT THU OCT 3 2013
FRIDAY NIGHT...NAM...GFS AND EC MODELS PLACE THE UPPER LOW OVER THE
NE CORNER OF THE STATE AT 00Z SAT...AND THEN QUICKLY MOVING THE
SYSTEM OFF TO THE E-NE THROUGH THE NIGHT. STRONG GUSTY NORTH WINDS
ARE FORECAST TO CONTINUE THROUGH THE EARLY EVENING FOR THE E PLAINS
AS WRAPAROUND FROM THE DEPARTING SYSTEM DRAWS A STRONG COLD POOL
DOWN INTO THE CWA. MODELS ARE NOT SHOWING A LOT OF PCPN WITH THIS
SYSTEM...SO THE MAIN STORY WILL BE INITIALLY THE STRONG WINDS BUT
THEN THE SIGNIFICANTLY COLDER AIR OVERNIGHT INTO EARLY SAT MORNING.
THIS PROMPTED A FREEZE WATCH ISSUANCE EARLIER TODAY...IN EFFECT FROM
MIDNIGHT FRI THROUGH 9 AM SAT MORN...FOR THE I-25 CORRIDOR AS WELL
AS CROWLEY AND OTERO COUNTIES. THE MAIN AREA THOUGH MOST LIKELY WILL
BE ALONG THE I-25 CORRIDOR AND NEAR THE MTS WHERE THE COLD AIR WILL
POOL AND DROP MIN TEMPS DOWN INTO THE MID TO UPPER 20S.
SATURDAY THROUGH TUESDAY...THE UPPER SYSTEM QUICKLY EXITS TO THE
E-NE SAT MORNING...THEN MODELS INDICATE THAT AN UPPER RIDGE OF HIGH
PRESSURE WILL SLOWLY SLIDE EASTWARD ACROSS THE WESTERN HALF OF THE
COUNTRY THROUGH TUESDAY. LOOK FOR DRY CONDITIONS AND GRADUALLY
WARMING TEMPS OVER THE WEEKEND AND INTO THE BEGINNING OF THE NEXT
WORK WEEK. EXPECT 50S AND 60S ON SAT...60S AND 70S SUN...THEN 70S TO
AROUND 80 F BOTH MON AND TUE. THERE IS THE OUTSIDE CHANCE THAT SAT
NIGHT/SUN MORN WILL SEE ANOTHER FREEZE FOR THE EASTERN PLAINS DUE
TO CLEAR SKIES AND LINGERING COLD AIR.
WEDNESDAY AND THURSDAY...EC AND GFS MODELS INDICATE THAT ANOTHER
UPPER TROUGH WILL DROP DOWN ACROSS THE GREAT BSAIN BY
MID-WEEK...BRINGING WARM AND DRY CONDITIONS DUE TO SW FLOW ON WED.
BY WED NIGHT SHOWERS WILL RETURN TO THE CONTDVD...WITH COOLER TEMPS
AND A BETTER CHANCE FOR PCPN FOR ALL OF THE CWA ON THU. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 240 PM MDT THU OCT 3 2013
MAIN CONCERN AT ALL 3 TAF SITES WILL BE GUSTY WINDS NEXT 24H. A
STRONG COLD FRONT WILL CROSS KPUB AND KCOS TOMORROW MORNING AROUND
SUNRISE AND GUSTY NORTHWEST WINDS WILL DEVELOP TOMORROW MORNING INTO
TOMORROW AFTERNOON. NORTHWEST WINDS TO 15 TO 30+ KNTS WILL BE
POSSIBLE. GUSTY SOUTHWEST WINDS WILL ALSO OCCUR AT KALS SHIFTING TO
WNW LATER TOMORROW AFTERNOON. KALS SHOULD SEE VFR THROUGH THE PD.
FOR KCOS AND KPUB...THERE IS A LOW CHANCE THAT WE MAY SEE SOME LOW
CIGS LATER TONIGHT. SOME MEMBERS OF THE SREF ALONG WITH HRRR
GUIDANCE SHOW SOME LOW CIGS POSSIBLE...HOWEVER THE LARGE MAJORITY OF
THE GUIDANCE KEEPS LOW CIGS AWAY FROM KPUB AND KALS.
THERE MAY BE A FEW SHOWERS AT KCOS TOMORROW...BUT BRUNT OF PRECIP
SHOULD REMAIN NORTH ALONG THE PALMER DVD.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR
COZ083>089-093.
&&
$$
SHORT TERM...HODANISH
LONG TERM...MOORE
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1110 AM MDT THU OCT 3 2013
.UPDATE...ISSUED A COUPLE WATCHES...ONE FOR WIND...ANOTHER FOR
COLD. WITH REGARD TO WIND...A VERY STRONG PRESSURE GRADIENT WILL
SET UP ACROSS NORTHEAST COLORADO FRIDAY MORNING WITH ABOUT 12MB
DIFFERENCE BETWEEN GOODLAND KANSAS AND CHEYENNE. THERE IS ALSO
STRONG SUBSIDENCE WORKING ACROSS THE AREA BY AFTERNOON WHICH
SHOULD KEEP THE HIGH WINDS IN PLACE. FORECAST MODEL SOUNDINGS ALSO
SHOW 48-54KTS IN THE MIXED LAYER...A GOOD INDICATOR OF POTENTIAL
MAX GUSTS.
OTHER MAIN UPDATE WAS FOR THE FREEZE WATCH...WITH A KILLING FREEZE
EXPECTED ON ALL OF THE PLAINS WITH MOST IF NOT ALL LOCATIONS
DROPPING WELL INTO THE 20S.
SNOW FORECAST LOOKS PRETTY GOOD AT THIS POINT...OVERALL 12Z MODEL
RUNS SHOW LITTLE CHANGE AMONGST THE AVERAGES FROM PREVIOUS RUNS.
DIDNT SEE MUCH IN 12Z ANALYSIS TO ARGUE WITH THIS STORM TRACK
EITHER TAKING HEAVIEST PRECIP OVER OUR NORTHERN MOUNTAINS AND FAR
NORTHERN PLAINS AREA. THERE IS STILL SEE POTENTIAL FOR SOME SNOW
ACCUMULATION NORTHERN BORDER AREA. WILL CONTINUE TO MONITOR.
&&
.AVIATION...MAIN CHANGE WILL BE TO HIT THE STRATUS DECK A LITTLE
HARDER AROUND 03Z GIVEN UPSTREAM OBSERVATIONS. PERSISTENCE OF
SHOWERS 08Z-16Z FRIDAY COULD BE LESS THAN PREVIOUSLY FORECAST
CONSIDERING DOWNSLOPE FLOW...BUT TEMPO STILL WARRANTED. THE
DOWNSLOPE WOULD ALSO HELP CEILINGS INCREASE THROUGH THE DAY
FRIDAY. NORTH/NORTHWEST WINDS WILL STRENGTHEN 12Z-15Z WITH GUSTS
AROUND 40 KTS THROUGH MUCH OF THE DAY.
&&
.PREV DISCUSSION... /ISSUED 347 AM MDT THU OCT 3 2013/
SHORT TERM...A STORM SYSTEM WILL MOVE INTO THE GREAT BASIN TODAY
AND THEN INTO WRN COLORADO BY TONIGHT. MEANWHILE SFC LOW PRES
WILL GRADUALLY INTENSIFY OVER SERN CO THRU TONIGHT. MOISTURE WILL
GRADUALLY INCREASE IN THE MTNS LATER THIS AFTN THRU TONIGHT AS THE
FLOW ALOFT REMAINS SWLY. MEANWHILE STG QG ASCENT WILL MOVE INTO
THE MTNS BY TONIGHT WITH DECENT LAPSE RATES SO SHOULD SEE SNOW
INCREASE BY MIDNIGHT ESPECIALLY IN THOSE AREAS FAVORED BY SWLY
FLOW NORTH OF I- 70 IN ZNS 31 AND 33.
EAST OF THE MTNS A WK FNTL BNDRY WILL REMAIN STALLED OVER THE PALMER
DIVIDE. THE RAP WANTS TO LIFT THIS BNDRY NORTHWARD WHILE THE HRRR
KEEPS IT OVER THE PALMER DIVIDE THRU THE AFTN. AS A RESULT THERE
ARE SIGNIFICANT TEMP DIFFERENCES IN SOME AREAS OF THE URBAN CORRIDOR
DEPENDING ON WHERE THIS BNDRY ENDS UP. FOR NOW WILL GO CLOSER TO
THE HRRR AND KEEP READINGS FM DENVER NORTH TO THE WY BORDER IN THE
UPPER 60S TO AROUND 70 WHILE FURTHER SOUTH WILL HAVE HIGHS IN THE
MID TO UPPER 70S WHERE SLY WINDS CAUSE DOWNSLOPE WARMING OVER THE
PALMER DIVIDE. OVER THE FAR NERN PLAINS REST OF THE PLAINS WILL
HAVE READINGS IN THE LOWER TO MID 60S. AS FOR PCPN SOUNDINGS SHOW A
STG CAP IN PLACE THRU THE AFTN SO TSTM CHANCES LOOK RATHER LOW.
FOR TONIGHT AS MAIN SFC LOW INTENSIFIES OVER SERN CO LOW LVL FLOW
OVER NERN CO SHOULD BE MAINLY ELY INTO THE NRN FOOTHILLS. AS QG
ASCENT BEGINS TO AFFECT THE AREA TONIGHT PCPN SHOULD INCREASE ALONG
THE FRONT RANGE OVERNIGHT. THE GFS KEEPS THE MAIN AREA OF PCPN
NORTH OF DENVER TO THE WY BORDER WHILE THE ECMWF AND GEM HAVE IT A
BIT FURTHER SOUTH. AT THIS POINT WILL KEEP THE HIGHEST POPS FM
DENVER NORTH TO THE WY BORDER WITH LOWER CHANCES SOUTH OF A DENVER
TO AKRON LINE. AS FAR AS PCPN TYPE LATEST DATA SUGGESTS PCPN MAY
NOT MIX WITH OR CHANGE TO SNOW UNTIL AFTER 12Z AT LOWER ELEVATIONS.
IN THE NRN FOOTHILLS NOT SURE ABOUT TIMING OF CHANGEOVER SO WILL
LEAVE CURRENT WATCH IN PLACE.
LONG TERM...THE VARIOUS MODELS SHOW THE UPPER CLOSED LOW SOMEWHERE
OVER THE NORTHWESTERN QUARTER OF COLORADO AT 12Z FRIDAY MORNING.
BY 00Z FRIDAY AFTERNOON...THE UPPER CLOSE LOW IS ANYWHERE FROM
THE NORTHWEST TIP OF COLORADO TO NORTH CENTRAL NEBRASKA. THE UPPER
TROUGH AXIS DOESN`T PUSH COMPLETELY EAST OUT OF THE CWA UNTIL
SATURDAY AT 18Z. THE FLOW ALOFT IS STRONG AND SOUTHWESTERLY FOR
THE CWA ON FRIDAY INTO FRIDAY EVENING. THE FLOW ALOFT DECREASES
SIGNIFICANTLY AND IS NORTH-NORTHEASTERLY FROM WEST TO EAST OVER
THE CWA FROM 06Z FRIDAY NIGHT INTO EARLY SATURDAY AFTERNOON. FOR
SATURDAY AFTERNOON AND SATURDAY NIGHT...NORTH-NORTHEASTERLY FLOW
ALOFT IS PROGGED IN THE 50 TO 70 KNOT RANGE. THE QG VERTICAL
VELOCITY FIELDS HAVE STRONG UPWARD SYNOPTIC SCALE ENERGY OVER THE
CWA FRIDAY MORNING...STRONGEST OVER THE NORTHERN CWA. IT IS STRONGER
YET OVER WYOMING. DOWNWARD MOTION IS ALREADY MOVING IN FROM THE
WEST BY FRIDAY AFTERNOON. DOWNWARD ENERGY IS PROGGED FRIDAY NIGHT
..THROUGH SATURDAY NIGHT. THE LOW LEVEL PRESSURE AND WIND FIELDS
SHOW A COLD FRONT TO MOVE DOWN ACROSS THE FORECAST AREA AT AROUND
12Z-15Z FRIDAY MORNING. BY 18Z FRIDAY MIDDAY...THE SURFACE LOW IS
WELL EAST-NORTHEAST OF THE CWA. BY MID DAY FRIDAY...THE BOUNDARY
LAYER FLOW HAS A WESTERLY COMPONENT TO THE NORTHERLY WINDS ON ALL
THE MODELS. THE NORTHWESTERLIES CONTINUE THE REST OF FRIDAY...
FRIDAY NIGHT...SATURDAY AND SATURDAY NIGHT...AT LEAST FROM THE
DIVIDE EASTWARD. THEY ARE PRETTY STRONG OVER THE EASTERN TWO-THIRDS
OF THE PLAINS FROM 18Z FRIDAY TO 18Z SATURDAY. FOR MOISTURE...
THERE IS PLENTY OVER THE CWA FRIDAY...ESPECIALLY THE MOUNTAINS.
DRYING KICKS IN FRIDAY NIGHT...WITH THE GFS SHOWING MORE...
ESPECIALLY OVER THE NORTHEAST CORNER WITH THE WRAP AROUND. THE CWA
DRIES OUT SIGNIFICANTLY BY 12-18Z SATURDAY AND STAYS THAT WAY. THE
QPF FIELDS...EVEN THE MOST WET GFS...DO NOT HAVE SIGNIFICANT
PRECIPITATION AMOUNTS ON FRIDAY. SOME OF THEM SHOW A TAD FRIDAY
NIGHT. SO FOR POPS ON FRIDAY OVER THE FOOTHILLS AND PLAINS...IT
COMES DOWN TO THE STRENGTH OF THE SYNOPTIC SCALE ENERGY WINNING
OVER THE DRYING DOWNSLOPING WINDS. I`M NOT TOO EXCITED ABOUT IT.
HIGHEST POPS IN THE MOUNTAINS AND NORTHERN BORDER FOR SURE...
LOWEST OVER THE SOUTHEASTERN PLAINS. THE STRONG QG ASCENT SHOULD
ACCOUNT FOR SOME MEASURABLE PRECIPITATION OVER MOST OF THE PLAINS
IN SPITE OF THE DOWNSLOPING. WON`T CHANGE CURRENT POPS VERY MUCH.
WILL GO WITH SHORT TERM FORECASTER CONCERNING SNOW HIGHLIGHTS.
CONCERNING TEMPERATURES...THE MODELS NOW SHOW FRIDAY TO BE A BIT
WARMER...AND FRIDAY NIGHT...LESS CLOUDY...AND A BIT COLDER. A
DECENT FREEZE IS LIKELY ACROSS ALL THE CWA FRIDAY OVERNIGHT/
SATURDAY MORNING. NO HIGHLIGHTS FOR THAT YET. AFTER ALL..IT IS
RIGHT AROUND NOW WHEN OUT NORMAL FIRST FROST OCCURS. FRIDAY`S
HIGHS ARE SOME 12-18 DEGREES C COLDER THAN TODAY`S EXPECTED HIGHS.
SATURDAY`S HIGHS WARM UP 4-8 C OVER FRIDAY`S. FOR THE LATER DAYS
..SUNDAY THROUGH WEDNESDAY...MODELS SHOW AN UPPER RIDGE TO MOVE
SLOWLY EASTWARD THROUGH THE PERIOD. THE FLOW ALOFT FOR THE CWA
WILL BE NORTHWESTERLY...BUT FAIRY WEAK SUNDAY INTO EARLY TUESDAY.
LATER TUESDAY AND WEDNESDAY...THE FLOW ALOFT WILL BECOME
SOUTHWESTERLY WITH THE NEXT UPPER TROUGH/CLOSED LOW OVER OR NEAR
THE GREAT BASIN BY WEDNESDAY. THE ECMWF SOLUTION GIVES OUR CWA
BETTER CHANCES OF PRECIPITATION COMPARED TO THE GFS. WE`LL SEE.
BOTH MODELS KEEP IT PRETTY DRY HERE...AT LEAST WELL INTO
WEDNESDAY.
AVIATION...THERE ARE SOME DIFFERENCES BETWEEN THE RAP AND HRRR
AS FAR AS WHERE A SFC LOW WILL BE LOCATED EARLY THIS AFTN. THE
HRRR KEEPS IT SOUTH OF DIA WITH WINDS GENERALLY ENE THIS AFTN
WHILE THE RAP HAS IT FURTHER NORTH WITH WINDS MORE ESE. FOR NOW
WILL GO WITH THE HRRR. OVERALL AIRMASS IS CAPPED THIS AFTN SO TSTM
THREAT LOOKS LOW. FOR TONIGHT SHOWERS WILL INCREASE ESPECIALLY
AFTER MIDNIGHT WITH CEILINGS BECOMING MVFR. AT THIS TIME IT LOOKS
LIKE ANY CHANGE OVER TO SNOW WOULD OCCUR AFTER 12Z ON FRI.
HYDROLOGY...RAIN TONIGHT MAY LEAD TO ACCUMULATIONS OF ONE HALF
INCH TO ONE INCH IN THE NORTHERN FOOTHILLS BY 12Z FRIDAY. SOME OF
THIS RAIN WILL FALL AS SNOW AFTER MIDNIGHT. SOME MINOR RISES MAY
OCCUR ON SOME OF THE STREAMS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING FOR
COZ038>051.
HIGH WIND WATCH FROM FRIDAY MORNING THROUGH FRIDAY AFTERNOON FOR
COZ042-044-046>051.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON
FOR COZ035.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY
FOR COZ031-033.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RJK
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
347 AM MDT THU OCT 3 2013
.SHORT TERM...A STORM SYSTEM WILL MOVE INTO THE GREAT BASIN TODAY
AND THEN INTO WRN COLORADO BY TONIGHT. MEANWHILE SFC LOW PRES
WILL GRADUALLY INTENSIFY OVER SERN CO THRU TONIGHT. MOISTURE WILL
GRADUALLY INCREASE IN THE MTNS LATER THIS AFTN THRU TONIGHT AS THE
FLOW ALOFT REMAINS SWLY. MEANWHILE STG QG ASCENT WILL MOVE INTO
THE MTNS BY TONIGHT WITH DECENT LAPSE RATES SO SHOULD SEE SNOW
INCREASE BY MIDNIGHT ESPECIALLY IN THOSE AREAS FAVORED BY SWLY
FLOW NORTH OF I- 70 IN ZNS 31 AND 33.
EAST OF THE MTNS A WK FNTL BNDRY WILL REMAIN STALLED OVER THE PALMER
DIVIDE. THE RAP WANTS TO LIFT THIS BNDRY NORTHWARD WHILE THE HRRR
KEEPS IT OVER THE PALMER DIVIDE THRU THE AFTN. AS A RESULT THERE
ARE SIGNIFICANT TEMP DIFFERENCES IN SOME AREAS OF THE URBAN CORRIDOR
DEPENDING ON WHERE THIS BNDRY ENDS UP. FOR NOW WILL GO CLOSER TO
THE HRRR AND KEEP READINGS FM DENVER NORTH TO THE WY BORDER IN THE
UPPER 60S TO AROUND 70 WHILE FURTHER SOUTH WILL HAVE HIGHS IN THE
MID TO UPPER 70S WHERE SLY WINDS CAUSE DOWNSLOPE WARMING OVER THE
PALMER DIVIDE. OVER THE FAR NERN PLAINS REST OF THE PLAINS WILL
HAVE READINGS IN THE LOWER TO MID 60S. AS FOR PCPN SOUNDINGS SHOW A
STG CAP IN PLACE THRU THE AFTN SO TSTM CHANCES LOOK RATHER LOW.
FOR TONIGHT AS MAIN SFC LOW INTENSIFIES OVER SERN CO LOW LVL FLOW
OVER NERN CO SHOULD BE MAINLY ELY INTO THE NRN FOOTHILLS. AS QG
ASCENT BEGINS TO AFFECT THE AREA TONIGHT PCPN SHOULD INCREASE ALONG
THE FRONT RANGE OVERNIGHT. THE GFS KEEPS THE MAIN AREA OF PCPN
NORTH OF DENVER TO THE WY BORDER WHILE THE ECMWF AND GEM HAVE IT A
BIT FURTHER SOUTH. AT THIS POINT WILL KEEP THE HIGHEST POPS FM
DENVER NORTH TO THE WY BORDER WITH LOWER CHANCES SOUTH OF A DENVER
TO AKRON LINE. AS FAR AS PCPN TYPE LATEST DATA SUGGESTS PCPN MAY
NOT MIX WITH OR CHANGE TO SNOW UNTIL AFTER 12Z AT LOWER ELEVATIONS.
IN THE NRN FOOTHILLS NOT SURE ABOUT TIMING OF CHANGEOVER SO WILL
LEAVE CURRENT WATCH IN PLACE.
.LONG TERM...THE VARIOUS MODELS SHOW THE UPPER CLOSED LOW SOMEWHERE
OVER THE NORTHWESTERN QUARTER OF COLORADO AT 12Z FRIDAY MORNING.
BY 00Z FRIDAY AFTERNOON...THE UPPER CLOSE LOW IS ANYWHERE FROM
THE NORTHWEST TIP OF COLORADO TO NORTH CENTRAL NEBRASKA. THE UPPER
TROUGH AXIS DOESN`T PUSH COMPLETELY EAST OUT OF THE CWA UNTIL
SATURDAY AT 18Z. THE FLOW ALOFT IS STRONG AND SOUTHWESTERLY FOR
THE CWA ON FRIDAY INTO FRIDAY EVENING. THE FLOW ALOFT DECREASES
SIGNIFICANTLY AND IS NORTH-NORTHEASTERLY FROM WEST TO EAST OVER
THE CWA FROM 06Z FRIDAY NIGHT INTO EARLY SATURDAY AFTERNOON. FOR
SATURDAY AFTERNOON AND SATURDAY NIGHT...NORTH-NORTHEASTERLY FLOW
ALOFT IS PROGGED IN THE 50 TO 70 KNOT RANGE. THE QG VERTICAL
VELOCITY FIELDS HAVE STRONG UPWARD SYNOPTIC SCALE ENERGY OVER THE
CWA FRIDAY MORNING...STRONGEST OVER THE NORTHERN CWA. IT IS STRONGER
YET OVER WYOMING. DOWNWARD MOTION IS ALREADY MOVING IN FROM THE
WEST BY FRIDAY AFTERNOON. DOWNWARD ENERGY IS PROGGED FRIDAY NIGHT
...THROUGH SATURDAY NIGHT. THE LOW LEVEL PRESSURE AND WIND FIELDS
SHOW A COLD FRONT TO MOVE DOWN ACROSS THE FORECAST AREA AT AROUND
12Z-15Z FRIDAY MORNING. BY 18Z FRIDAY MIDDAY...THE SURFACE LOW IS
WELL EAST-NORTHEAST OF THE CWA. BY MID DAY FRIDAY...THE BOUNDARY
LAYER FLOW HAS A WESTERLY COMPONENT TO THE NORTHERLY WINDS ON ALL
THE MODELS. THE NORTHWESTERLIES CONTINUE THE REST OF FRIDAY...
FRIDAY NIGHT...SATURDAY AND SATURDAY NIGHT...AT LEAST FROM THE
DIVIDE EASTWARD. THEY ARE PRETTY STRONG OVER THE EASTERN TWO-THIRDS
OF THE PLAINS FROM 18Z FRIDAY TO 18Z SATURDAY. FOR MOISTURE...
THERE IS PLENTY OVER THE CWA FRIDAY...ESPECIALLY THE MOUNTAINS.
DRYING KICKS IN FRIDAY NIGHT...WITH THE GFS SHOWING MORE...
ESPECIALLY OVER THE NORTHEAST CORNER WITH THE WRAP AROUND. THE CWA
DRIES OUT SIGNIFICANTLY BY 12-18Z SATURDAY AND STAYS THAT WAY. THE
QPF FIELDS...EVEN THE MOST WET GFS...DO NOT HAVE SIGNIFICANT
PRECIPITATION AMOUNTS ON FRIDAY. SOME OF THEM SHOW A TAD FRIDAY
NIGHT. SO FOR POPS ON FRIDAY OVER THE FOOTHILLS AND PLAINS...IT
COMES DOWN TO THE STRENGTH OF THE SYNOPTIC SCALE ENERGY WINNING
OVER THE DRYING DOWNSLOPING WINDS. I`M NOT TOO EXCITED ABOUT IT.
HIGHEST POPS IN THE MOUNTAINS AND NORTHERN BORDER FOR SURE...
LOWEST OVER THE SOUTHEASTERN PLAINS. THE STRONG QG ASCENT SHOULD
ACCOUNT FOR SOME MEASURABLE PRECIPITATION OVER MOST OF THE PLAINS
IN SPITE OF THE DOWNSLOPING. WON`T CHANGE CURRENT POPS VERY MUCH.
WILL GO WITH SHORT TERM FORECASTER CONCERNING SNOW HIGHLIGHTS.
CONCERNING TEMPERATURES...THE MODELS NOW SHOW FRIDAY TO BE A BIT
WARMER...AND FRIDAY NIGHT...LESS CLOUDY...AND A BIT COLDER. A
DECENT FREEZE IS LIKELY ACROSS ALL THE CWA FRIDAY OVERNIGHT/
SATURDAY MORNING. NO HIGHLIGHTS FOR THAT YET. AFTER ALL..IT IS
RIGHT AROUND NOW WHEN OUT NORMAL FIRST FROST OCCURS. FRIDAY`S
HIGHS ARE SOME 12-18 DEGREES C COLDER THAN TODAY`S EXPECTED HIGHS.
SATURDAY`S HIGHS WARM UP 4-8 C OVER FRIDAY`S. FOR THE LATER DAYS
...SUNDAY THROUGH WEDNESDAY...MODELS SHOW AN UPPER RIDGE TO MOVE
SLOWLY EASTWARD THROUGH THE PERIOD. THE FLOW ALOFT FOR THE CWA
WILL BE NORTHWESTERLY...BUT FAIRY WEAK SUNDAY INTO EARLY TUESDAY.
LATER TUESDAY AND WEDNESDAY...THE FLOW ALOFT WILL BECOME
SOUTHWESTERLY WITH THE NEXT UPPER TROUGH/CLOSED LOW OVER OR NEAR
THE GREAT BASIN BY WEDNESDAY. THE ECMWF SOLUTION GIVES OUR CWA
BETTER CHANCES OF PRECIPITATION COMPARED TO THE GFS. WE`LL SEE.
BOTH MODELS KEEP IT PRETTY DRY HERE...AT LEAST WELL INTO
WEDNESDAY.
&&
.AVIATION...THERE ARE SOME DIFFERENCES BETWEEN THE RAP AND HRRR
AS FAR AS WHERE A SFC LOW WILL BE LOCATED EARLY THIS AFTN. THE
HRRR KEEPS IT SOUTH OF DIA WITH WINDS GENERALLY ENE THIS AFTN
WHILE THE RAP HAS IT FURTHER NORTH WITH WINDS MORE ESE. FOR NOW
WILL GO WITH THE HRRR. OVERALL AIRMASS IS CAPPED THIS AFTN SO TSTM
THREAT LOOKS LOW. FOR TONIGHT SHOWERS WILL INCREASE ESPECIALLY
AFTER MIDNIGHT WITH CEILINGS BECOMING MVFR. AT THIS TIME IT LOOKS
LIKE ANY CHANGE OVER TO SNOW WOULD OCCUR AFTER 12Z ON FRI.
&&
.HYDROLOGY...RAIN TONIGHT MAY LEAD TO ACCUMULATIONS OF ONE HALF
INCH TO ONE INCH IN THE NORTHERN FOOTHILLS BY 12Z FRIDAY. SOME OF
THIS RAIN WILL FALL AS SNOW AFTER MIDNIGHT. SOME MINOR RISES MAY
OCCUR ON SOME OF THE STREAMS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT FRIDAY
FOR COZ031-033.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON
FOR COZ035.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
809 PM MDT WED OCT 2 2013
.UPDATE...WILL KEEP LOW POPS IN THE FORECAST FOR AFTER MIDNIGHT
OVER NORTHEAST COLORADO. THE RAP AND HRRR CONTINUE TO SHOW A
COUPLE OF SHOWERS LATE TONIGHT. EAST TO NORTHEAST WINDS OVER
EASTERN COLORADO WILL ADVECT MOISTURE INTO THE STATE AND COULD
PRODUCE LOW CLOUDS AND PERHAPS SOME DRIZZLE. BECAUSE OF THIS WILL
ADD PATCHY FOG TO PARTS OF THE EASTERN PLAINS. ONLY OTHER CHANGES
WERE TO ADJUST THE FORECAST TOWARDS CURRENT TRENDS.
&&
.PREV DISCUSSION... /ISSUED 544 PM MDT WED OCT 2 2013/
&&
.AVIATION...WEAK SURGE MOVING IN FROM THE NORTHEAST CONTINUES TO
ENHANCE THE EAST AND NORTHEAST WINDS WITH SOME GUSTS UP TO 20 KT.
WINDS SHOULD SHIFT THROUGH THE SOUTHEAST THIS EVENING GRADUALLY
SHIFTING TO A LIGHT DRAINAGE WIND OVERNIGHT. HOWEVER SOME RECENT
HIRES MODELS ARE INDICATING A SHIFT THROUGH THE NORTH THEN WEST
THEN TO DRAINAGE AS THE SURFACE LOW MOVES OUT TO SOUTHEASTERN CO.
WILL SHOW A SLIGHT NORTHEAST TREND FOR A FEW HOURS...BUT THEN TAKE
IT BACK THROUGH SOUTHEAST. WILL HAVE TO MONITOR THE PATTERN AND
ADJUST THE TAF AS NECESSARY. THERE IS A VERY SLIGHT CHANCE OF
SHOWERS BY THURSDAY LATE AFTERNOON INTO EARLY EVENING WITH THE
NEXT SIGNIFICANT FRONT TO PUSH SOUTH ACROSS THE AREA IN THE
EVENING. ANY SIGNIFICANT PRECIP WILL WAIT UNTIL AFTER 00Z FRIDAY.
.PREV DISCUSSION... /ISSUED 255 PM MDT WED OCT 2 2013/
SHORT TERM...COLORADO STILL REMAINS UNDER A DRY...SOUTHWEST FLOW
ALOFT AHEAD OF THE DEEPENING UPPER TROF OVER THE PACIFIC
NORTHWEST. A LOW LEVEL SURGE HAS MOVED INTO NORTHEAST COLORADO AS
LOW LEVEL WINDS HAVE SHIFTED NORTHEAST AND INCREASING. THE AIRMASS
IS STILL RATHER DRY BEHIND THE FRONT BUT IS RESULTING IN SOME
CONVERGENCE IN SOME CUMULUS IN THE HIGHER FOOTHILLS. ADDED A
SLIGHT CHANCE OF SHOWERS WITH THIS BUT DON`T SEE MUCH VERTICAL
DEVELOPMENT AS LOW LEVELS ARE STILL RATHER DRY. WILL ALSO MAINTAIN
A SLIGHT CHANCE OF STORMS OVER THE FAR NORTHEAST CORNER TONIGHT
BUT EXPECT MUCH OF THE ACTIVITY WILL BE FURTHER EAST INTO
NEBRASKA AND KANSAS.
THE UPPER LEVEL TROF WILL APPROACH COLORADO ON THURSDAY WITH
MOISTURE BEGINNING TO DEEPEN IN THE MOUNTAINS DURING THE
AFTERNOON. THIS WILL LEAD TO A CHANCE OF SHOWERS AND A FEW
THUNDERSTORMS. STILL THE BEST MOISTURE AND UPPER LEVEL FORCING
WILL BE STARTING THURSDAY NIGHT. COOLER TEMPERATURES ON THE PLAINS
THURSDAY WITH A BIT OF POST FRONTAL COOLING.
LONG TERM...THE NEXT STORM SYSTEM MOVING INTO THE PACIFIC
NORTHWEST THIS AFTN IS STILL EXPECTED TO MOVE ACROSS SOUTHERN
WYOMING AND NORTHERN COLORADO THURSDAY NIGHT AND FRIDAY. THE MDLS
STILL DIFFER AS TO HOW FAR NORTH OR SOUTH THE TRACK WILL
TAKE...WILL CONTINUE TO GO WITH THE MORE SRN SOLUTIONS WHICH MOVE
THE SYSTEM ACROSS NORTHERN COLORADO. A STRONG UPPER JET WILL
PRECEDE THE TROUGH AXIS AND COULD HELP TO PRODUCE SOME ENHANCED
BANDS OF SNOW THURSDAY NIGHT. THE MDLS GENERATE MDT TO STG QG
ASCENT IN THE MID LEVELS THURSDAY NIGHT...THEN TRANSLATE THIS TO
THE EAST ON FRIDAY. WILL CONTINUE THE WINTER STORM WATCH FOR THE
NORTH CENTRAL MOUNTAINS AND NORTHERN FRONT RANGE FOOTHILLS. MDLS
STILL GENERATE UPWARDS TO A FOOT OF SNOW IN THESE AREA THROUGH
FRIDAY. ANY UPSLOPE ALONG THE FRONT RANGE APPEARS TO BE
SHALLOW AND BRIEF...WITH THE LOWER LEVELS TRANSITIONING TO
NORTH/NORTHWEST FRIDAY MORNING. DECREASING QG ASCENT FRIDAY
MORNING WILL BE FOLLOWED BY STRONG MID LEVEL SUBSIDENCE FRIDAY
AFTN AND EVENING...SO SHOULD SEE SNOW DECREASING/DIMINISHING AT
THAT TIME. AS FOR THE URBAN CORRIDOR AND NORTHEAST PLAINS...STILL
SOME DIFFICULTY DELINEATING RAIN/SNOW MIX VS SNOW AROUND 12Z
FRIDAY. IF PCPN DOES TURN TO SNOW IT WILL BE IN THE 09Z-15Z
WINDOW. FOR NOW WL CONTINUE WITH RAIN/SNOW MIX IN THE GRIDS. ANY
SNOW ACCUMULATIONS WILL BE CONFINED TO GRASSY AREAS AND SHOULD BE
MINIMAL...LESS THAN ONE INCH. WARM GROUND SURFACE TEMPERATURES
AHEAD OF THIS SYSTEM AND BRIEF TIME FRAME FOR POTENTIAL SNOWFALL
SHOULD KEEP SNOW TOTALS ON THE LIGHT SIDE. STRONG PRESSURE
GRADIENT ACROSS THE NORTHEAST PLAINS IN THE AFTN WILL ALLOW FOR
FAIRLY STRONG NLY WINDS IN THE LATE MORNING AFTN...WITH GUSTY IN
THE 40-50 MPH RANGE. NOT HIGHLIGHT MATERIAL BUT WILL NEED TO KEEP
AN EYE IN THIS. CLEARING SKIES FRIDAY NIGHT WILL LEAD TO FREEZING
TEMPERATURES BY SATURDAY MORNING. OVERNIGHT LOWS COULD DROP IN THE
MID 20S TO LOWER 30S...SO FREEZE WATCH MAY BE NECESSARY FOR THE
URBAN CORRIDOR AND NORTHEAST PLAINS AT SOME POINT. FOR THE REST OF
THE PERIOD...UPPER LEVEL RIDGING AND A DRY NORTHEAST FLOW FOR THE
WEEKEND. THE FLOW WILL BECOME MORE ZONAL WITH TEMPERATURES BACK
INTO THE 60S FOR MONDAY AND TUESDAY. ANOTHER SYSTEM MAY POSSIBLY
IMPACT COLORADO LATE WEDNESDAY AS IT DROPS OUT OF THE NORTHERN
ROCKIES/CANADA.
AVIATION...WEAK SURGE MOVING IN FROM THE NORTHEAST AND WILL
ENHANCE THE EAST AND NORTHEAST WINDS FOR THE REST OF THIS
AFTERNOON WITH SOME GUSTS UP TO 20 KT. WINDS WILL REMAIN EAST AND
SOUTHEAST THIS EVENING BEFORE GRADUALLY SHIFTING TO A LIGHT
DRAINAGE WIND OVERNIGHT. THERE IS A VERY SLIGHT CHANCE OF SHOWERS
BY THURSDAY AFTERNOON BUT WON`T MENTION IN TAFS FOR NOW. ANY
SIGNIFICANT PRECIP WILL WAIT UNTIL AFTER 00Z FRIDAY.
.HYDROLOGY...DRY CONDITIONS FOR NEXT 18 HOURS. WITH THE NEXT
INCOMING TROF MODELS SHOWING QUITE A WIDE VARIETY OF QPF AMOUNTS
WITH UP TO AN INCH ESPECIALLY FURTHER NORTH OVER LARIMER COUNTY
BY LATE FRIDAY. ONCE THE COLD AIR COMES IN LATE THURSDAY NIGHT
THEN SOME OF THE LIQUID WILL TURN TO SNOW IN THE FOOTHILLS.
OVERALL SHOULD SEE ONLY MINIMAL RISES ON RIVERS AND STREAMS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
AFTERNOON FOR COZ035.
WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR COZ031-033.
&&
$$
UPDATE...MEIER
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS ALBANY NY
943 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER GREAT LAKES
REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL PRODUCE SOME
SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH TODAY ACROSS THE
REGION. INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THIS
BOUNDARY IN THE VICINITY OF THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM...SHOWERS HAVE BECOME NUMEROUS FROM THE EASTERN MOHAWK
AND SCHIHARIE VALLEYS TO SOUTHERN VERMONT AND BERKSHIRE COUNTY. HAVE
RAISED POPS THERE TO LIKELY FOR THE REST OF THE MORNING...WHILE
KEEPING CHANCE POPS IN ALL AREAS DURING THE AFTERNOON. REST OF THE
PREVIOUS FORECAST PACKAGE IS GENERALLY UNCHANGED.
PREV DISC...
SURFACE ANALYSIS HAS A WARM FRONT DRAPED ACROSS WESTERN NY INTO
CENTRAL PA AND OFF THE MID ATLANTIC COAST. IN THE UPPER
LEVELS...H2O VAPOR LOOP SHOWS A WEAK SHORT WAVE APPROACHING
WESTERN NY WHERE RUC13 ISENTROPIC ANALYSIS ON THE 300-305K SURFACE
REVEALS BROAD LIFT. REGIONAL RADARS CONFIRM THIS WITH SHOWERS AND
SOME THUNDERSTORMS /PER THE NLDN/ ACROSS THE MOHAWK VALLEY WITH
MORE CONCENTRATION OF ACTIVITY ACROSS WESTERN NY. TRENDS FOR THE
DAYLIGHT HOURS ARE FOR ADDITIONAL SHOWERS AND SOME THUNDERSTORMS
TO MOVE ACROSS THE REGION WITH THE BETTER CONCENTRATION ALONG THE
I90 CORRIDOR WHERE THE WARM FRONT IS FORECAST TO BE PLACED WITH
ADDITIONAL MID LEVEL INSTABILITY PER THE SHOWALTER VALUES AROUND
0C. THIS TOO IS SUGGESTED BY THE HRRR EXPERIENTIAL REFLECTIVITY
FORECASTS. WITH CONSIDERABLE CLOUD COVER EXPECTED...HAVE SHADED ON
THE COOLER SIDE OF THE GUIDANCE.
THE AFOREMENTIONED SHORT WAVE IS FORECAST TO EXIT OUR REGION BY
THIS EVENING. SOME RESIDUAL SHOWERS AND PERHAPS A RUMBLE OF
THUNDER ARE EXPECTED THROUGH EARLY THIS EVENING...THEN ISOLATED
ACTIVITY FOR THE REMAINDER OF THE OVERNIGHT PERIOD. WARM FRONT
WILL BE IN THE VICINITY OF THE REGION SO CLOUD COVER WILL LIKELY
BE IN PLACE AND POCKETS OF DRIZZLE AS THE LOWER LEVELS ARE
EXPECTED TO BE QUITE MOIST PER TH BUFR SOUNDINGS. LOW LEVEL FLOW
SLOWLY INCREASES FROM THE NORTH WHICH WILL PLAY HAVOC ON
TEMPERATURES TONIGHT. GUIDANCE NUMBERS ARE RATHER CLOSE AS WE
UTILIZED A BLENDED APPROACH. HOWEVER...IF THE DRAINAGE IS A BIT
STRONGER...THEN TEMPERATURES COULD BE A LITTLE COOLER.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
THE CENTRAL PLAINS STORM IS FORECAST TO BE QUITE MATURE AT THIS
TIME FRAME. MEANWHILE...THE WARM FRONT REMAINS IN THE VICINITY
WITH SOME TENDENCY TO SLIP A LITTLE FURTHER SOUTH AS HIGH PRESSURE
ACROSS SOUTHERN CANADA ATTEMPTS TO NOSE SOUTHWARD ACROSS OUR
REGION SATURDAY. EITHER WAY...CONSIDERABLE CLOUDINESS IS EXPECTED
AS LOWER LEVELS REMAIN QUITE MOIST ALONG WITH A SLIGHT CHANCE FOR
A SHOWER. WE WILL SHADE ON THE COOLER SIDE OF THE GUIDANCE
ENVELOPE AS THE LOW LEVEL NORTHERLY FLOW AND CLOUD COVER SHOULD
KEEP TEMPS INTO THE 60S FOR MOST LOCATIONS WITH LOWER 70S FOR THE
MID HUDSON VALLEY AND SOUTHERN LITCHFIELD COUNTY.
THE WARM FRONT WILL ATTEMPT TO SLOWLY LIFT NORTHWARD SATURDAY
NIGHT AND THROUGH SUNDAY. MOISTURE TRANSPORT AND ASSOCIATED LIFT
INCREASES TO OUR WEST AND NORTH WHERE WE WILL PLACE THE HIGHER
POPS. TEMPERATURES WILL BE RATHER STAGNATE AS SUGGESTED BY THE
GFS-MOS WITH NOT MUCH RANGE EXPECTED.
IT DOES SEEM WE WILL BECOME ENTRENCHED INTO THE WARM SECTOR DURING
SUNDAY BUT THE COMBINATION OF MARINE AIR INFLUENCE AND CLOUD COVER
THOSE H850 TEMPS INTO THE LOW-MID TEENS WILL NOT BE FULLY
REALIZED. THUS WE HAVE LOWERED HIGH TEMPERATURES A FEW DEGREES. AS
FOR PRECIP CHANCES...MAINLY TO OUR WEST AND NORTH ONCE AGAIN AND
AS THIS FRONT LIFTS FURTHER NORTH...SO WILL THE DECREASING
TENDENCY FOR SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED PERIOD WILL START OFF RATHER ACTIVE...BUT ANOTHER
EXTENDED PERIOD OF DRY AND MILD WEATHER WILL FOLLOW.
OUR REGION WILL BE IN A WARM SECTOR OF A FRONTAL SYSTEM ON SUNDAY
NIGHT. WITH PLENTY OF MOISTURE IN PLACE...THERE WILL BE A CHC FOR
RAIN SHOWERS ACROSS THE ENTIRE REGION. THE BEST CHC FOR RAIN SHOWERS
WILL BE ACROSS FAR NORTHWESTERN PARTS OF THE REGION...ESP TOWARDS
SUNRISE MONDAY. WITH A SOUTHERLY FLOW IN PLACE...IT WILL BE MILD
AND MUGGY...WITH MIN TEMPS IN THE MID 50S TO LOW 60S.
A STRONG COLD FRONT WILL BE MOVING ACROSS THE REGION SOMETIME MONDAY
INTO MONDAY EVENING. THE MODELS DON/T AGREE ON THE EXACT TIMING
RIGHT NOW...WITH THE 00Z GFS A LITTLE FASTER THAN THE 00Z ECMWF. BY
THIS POINT....NHC SHOWS THAT TC KAREN BE IN THE PROCESS OF
TRANSITIONING FROM A TROPICAL ENTITY...AND THE REMAINS LOOK TO BE
ABSORBED ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTH. STILL...A
STRONG LOW LEVEL JET OF 50-60 KTS WILL TRANSPORT PLENTY OF MOISTURE
UP ALONG THE FRONT FROM THE GULF OF MEXICO...WITH PWAT VALUES
EXCEEDING 1.50 INCHES ACROSS OUR REGION. WITH THE STRONG SFC
FORCING...A BAND OF LOCALLY HEAVY RAIN SHOWERS WILL BE POSSIBLE JUST
AHEAD AND ALONG THE FRONTAL BOUNDARY. ALONG WITH LIKELY POPS FOR
RAIN SHOWERS...WE WILL INCLUDE A SLIGHT CHC OF THUNDER...BUT
WIDESPREAD THUNDER DOESN/T APPEAR LIKELY DUE TO MEAGER AMOUNTS OF
INSTABILITY. IT WILL BE FAIRLY WARM ON MONDAY IN ADVANCE OF THE
FRONTAL BOUNDARY WITH MID 60S TO MID 70S ACROSS THE REGION. MIN
TEMPS WILL ON MONDAY NIGHT WILL BE COOLER THAN SUN NIGHT...BUT THE
EXACT TIMING WILL DEPEND JUST HOW MUCH COOLS OFF. FOR NOW...WE ARE
FORECASTING MIN TEMPS FROM THE LOW 40S IN THE DACKS TO THE MID 50S
IN THE MID HUDSON VALLEY AND NW CT.
WE WILL STILL ALLOW FOR A SHOWER ACROSS SOUTHERN AREAS TUESDAY
MORNING IN CASE THE FRONT SLOWS...OTHERWISE THE COLD FRONT SHOULD
HAVE PUSHED OFF TO OUR EAST BY TUESDAY...ALLOWING A DRIER AND
SOMEWHAT COOLER AIR MASS TO MOVE INTO OUR REGION. IT WILL BE DRY FOR
THE MID WEEK PERIOD /TUES AND WED/ WITH MAX TEMPS IN THE 60S...AND
LOWS IN THE 40S /SOME 30S ACROSS THE ADIRONDACKS AND SRN GREEN
MTNS/. THESE MAX TEMPS STILL LOOK A FEW DEGREES ABOVE NORMAL.
BY LATE IN THE WEEK...STRONG RIDGING WILL REESTABLISH ITSELF ALONG
THE EASTERN SEABOARD...AND EVEN MORE ABOVE NORMAL WARMTH WILL BE IN
PLACE FOR THURS/FRI. IT WILL CONTINUE TO BE DRY...WITH DAYTIME TEMPS
IN THE UPPER 60S TO MID 70S FOR VALLEY AREAS...AND MINS GENERALLY IN
THE MID 40S TO LOW 50S.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
A WARM FRONT IS SITUATED SOUTH OF THE REGION IS SLOWLY MOVING
NORTHWARD. OVC CIGS OF 4-6 KFT ARE IN PLACE ACROSS THE REGION.
REGIONAL MOSAIC RADAR SHOWS SOME SHOWERS WEST OF THE REGION...AND
THESE MAY AFFECT MAINLY THE NORTHERN SITES THROUGH THE MORNING
HOURS. WILL INCLUDE A VCSH AT ALL SITES WITH A TEMPO FOR MVFR
CIGS/VSBYS WITHIN RAIN SHOWERS FOR KALB/KGFL/KPSF. AT THIS
POINT...WIDESPREAD IFR CONDITIONS ARE NOT ANTICIPATED TODAY. LIGHT
AND VARIABLE WINDS ARE EXPECTED TODAY.
FLYING CONDITIONS WILL GENERALLY BE VFR DURING THE AFTN HOURS FOR
THE VALLEY TERMINALS...ALTHOUGH CIGS MAY REMAIN MVFR AT KPSF. WITH
LOW LEVEL MOISTURE REMAINING HIGH TONIGHT...ALL SITES LOOK TO HAVE
MVFR CIGS TONIGHT WITH MVFR BR POSSIBLE AT KPSF/KPOU AS WELL.
ALTHOUGH NOT AS WIDESPREAD AS THIS MORNING...STILL CANNOT RULE OUT A
SHOWER OR TWO THIS AFTERNOON INTO TONIGHT AS WELL. WINDS WILL BE
NEARLY CALM TONIGHT.
OUTLOOK...
SATURDAY-SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF
SHRA.
SUNDAY-MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
THE RH VALUES WILL FALL TO 50 TO 65 PERCENT THIS AFTERNOON...THEN
RECOVER TO 80 TO 100 PERCENT BY SATURDAY MORNING.
THE WINDS BECOME LIGHT TO CALM THIS MORNING AND SATURDAY
NIGHT...THEN BE FROM THE EAST TO NORTHEAST AT 5 TO 10 MPH DURING THE
DAYLIGHT HOURS TODAY.
A COLD FRONT WILL BRING WIDESPREAD SHOWERS TO THE REGION LATE
SUNDAY INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER
THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS
FOR EARLY OCTOBER.
THE DRY WEATHER STRETCH OVER THE PAST 10 DAYS OR SO WILL BE
COMING TO AN END AS A WARM FRONT APPROACHES ALONG WITH THE CHANCE
FOR SHOWERS FOR THE REMAINDER OF THIS WEEK AND INTO THE WEEKEND.
AT THIS TIME...QPF AMOUNTS RANGE FROM A TENTH OF AN INCH OVER THE
NRN PORTIONS OF THE HSA TO A THIRD OF AN INCH OVER THE SRN THIRD
FROM TONIGHT INTO SATURDAY MORNING.
THERE IS SIGNIFICANT UNCERTAINTY IN THE GUIDANCE IN THE TIMING
AND TRACK OF A STRONGER LOW PRESSURE SYSTEM AND ITS FRONTAL
BOUNDARY FOR LATE IN THE WEEKEND AND EARLY NEXT WEEK.
FURTHERMORE...WE CONTINUE TO MONITOR TRENDS ON THE TRACK OF TS
KAREN IN THE GULF OF MEXICO FROM THE GUIDANCE FROM THE NATIONAL
HURRICANE CENTER. THE AMOUNT OF RAINFALL VARIES GREATLY IN THE
GUIDANCE AT THIS TIME FOR PORTIONS OF EXTREME SRN NY AND NEW
ENGLAND EARLY IN THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/BGM
NEAR TERM...GJM/BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...BGM
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
659 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT WILL STALL JUST TO THE SOUTHWEST TODAY...LEADING TO
SOME SHOWERS AND POSSIBLY EVEN AN ISOLATED THUNDERSTORM TO THE
REGION. ANOTHER BRIEF PERIOD OF MOSTLY DRY WEATHER THEN RETURNS
LATE TONIGHT INTO SATURDAY. THE FRONT BEGINS TO LIFT NORTH OF THE
AREA AS A WARM FRONT SUNDAY YIELDING WARMER TEMPERATURES MONDAY
ALONG WITH A BETTER CHANCE OF WIDESPREAD SHOWERS EARLY NEXT
WEEK...AS A COLD FRONT SLOWLY MOVES ACROSS NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
SHOWERS ACROSS NY STATE CONTINUE TO MARCH EASTWARD INTO SOUTHERN
VT AND NH AT 7 AM. THESE SHOWERS WERE ASSOCIATED WITH THE LEADING
EDGE OF AN AIRMASS CHANGE ALOFT...WITH WARM AIR ADVECTING EASTWARD
ON A MODEST MID LEVEL JET. SOME INSTABILITY ALOFT SO DECIDED TO
LEAVE SLIGHT CHANCE OF AN ELEVATED TSTM TODAY ACROSS THE REGION.
06Z NAM AND GFS NOT CAPTURING THE SHOWER ACTIVITY VERY WELL. THE
LATEST HRRR AND 00Z ECMWF DOING A MUCH BETTER JOB. THUS HAVE
UPDATED HOURLY POPS TO BETTER REFLECT MOST RECENT RADAR TRENDS.
OTHERWISE PREVIOUS FORECAST ON TRACK.
ANY RAINFALL RECEIVED TODAY WILL BE NEEDED AS LAST MEASUREABLE
RAINFALL OCCURRED SEP 22! PREVIOUS DISCUSSION BELOW.
--------------------------------------------------------------
THE COMBINATION OF A SFC WARM FRONT STALLING TO THE SW AND A WEAK
DISTURBANCE MOVING THROUGH ZONAL FLOW ALOFT WILL LEAD TO MORE
UNSETTLED WX TODAY THAN WE HAVE SEEN OF LATE. LIFT IS RELATIVELY
WEAK WITH EACH OF THESE FEATURES...BUT PRECIPITAL WATERS ARE
EXPECTED TO REACH 1.5-1.75 INCHES. THEREFORE...EXPECTING SOME
SHOWERS TO SLIDE INTO THE W EARLY TODAY...THEN CONTINUE ESE
THROUGH THE DAY. AM ALREADY NOTING SOME WIDELY SCATTERED -SHRA
ON KBGM/KENX RADARS...WHICH WILL BE THE FIRST OF THESE -SHRA. AM
NOTING 40+ DBZ ON A FEW OF THESE -SHRA...WHICH CONFIRMS THE THREAT
THAT INDIVIDUAL CELLS COULD ACTUALLY BE BRIEFLY HEAVY GIVEN THE
HIGH MOISTURE CONTENT FOR EARLY OCT. ALSO...IN THE S AND W...AM
NOTING SFC LI/S NEAR TO BELOW 0...WITH K VALUES 30+...SO AN
ISOLATED RUMBLE OF THUNDER MAY ALSO ACCOMPANY THESE HEAVIER -SHRA
LATE THIS MORNING AND INTO THE EVENING. THESE -SHRA WILL LIKELY BE
HIT OR MISS...WITH SOME AREAS...PARTICULARLY TOWARD THE
NE...POSSIBLY SEEING LITTLE TO NO PRECIP. THIS IS DUE TO A
BUILDING SUBTROPICAL RIDGE OVER THE ERN CONUS...AND THE RESPONSE
OF SFC RIDGING ACROSS SRN QUEBEC AND NRN NEW ENGLAND...WHICH WILL
GRADUALLY SHUNT THE ATTENDANT SHORTWAVES TO THE S.
GIVEN A FAIR AMOUNT OF EXPECTED CLOUD COVER...PARTICULARLY IN THE
W INITIALLY...EXPECT TEMPERATURES TO REMAIN A BIT COOLER TODAY.
HIGHS IN THE W /WHERE CLOUD COVER IS LIKELY TO LINGER FOR THE
WHOLE DAY/ HIGHS WILL ONLY REACH INTO THE UPPER 60S...WHILE LOW TO
MID 70S ARE POSSIBLE IN THE E WITH A BETTER CHANCE FOR SUNSHINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
TONIGHT...
WEAK UPPER LVL DISTURBANCE WILL BE SLIDING ESE OF THE REGION WITH
TIME...ALLOWING FOR MID LVL RIDGING AND ATTENDANT INVERTED SFC
RIDGE FROM NRN NEW ENGLAND TO REGAIN CONTROL. THEREFORE...EXPECT
THAT ANY -SHRA/T-STORMS PRODUCED BY THE WEAK INSTABILITY AND
SHORTWAVE TO BE GRADUALLY WEAKENING AND SHIFTING ESE THEMSELVES
AS DIURNAL HEAT IS LOST AND THE BEST LIFT MOVES OFFSHORE. WILL
GRADUALLY BE LOWING POPS FROM N TO S WITH TIME. MAY BE THAT
CONDITIONS ARE MOSTLY DRY BY THE MORNING HOURS AS DRY AIR BUILDS
BACK INTO THE COLUMN AND THE UNSETTLED CONDITIONS DECOUPLE FROM
THE WARM FRONT STALLED UPSTREAM. MIN TEMPERATURES ARE EXPECTED TO
BE MILD THANKS TO CONTINUED CLOUD COVER AND HIGHER DWPTS FROM THE
GRADUALLY DRYING AIRMASS. EXPECT MOST MINS IN THE LOW TO MID 50S.
SAT...
MID LVL RIDGE CONTINUES TO BUILD FED BY STRONG WARM ADVECTION
AHEAD OF A STRONG CUTOFF APPROACHING THE GREAT LAKES. THIS ALLOWS
THE SFC HIGH PRES TO THE N TO GAIN CONTROL THROUGH THE DAY. AM
NOTING MORE STABLE AND DRIER SOUNDINGS ACROSS THE REGION WITH ONLY
WEAK ISENTROPIC LIFT AHEAD OF THE WARM FRONT TO THE SW.
THEREFORE...WILL SUGGEST ONLY SLIGHT CHANCE OR LOWER POPS THROUGH
THE DAY WITH A FOCUS ON THE SRN HALF OF THE REGION...CLOSER TO THE
FRONT ITSELF. IT IS VERY POSSIBLE THAT MANY LOCALES REMAIN DRY
THROUGH THE DAY...AND THAT BREAKS OF SUN ARE POSSIBLE ESPECIALLY
ACROSS THE N. THEREFORE...EXPECT SLIGHTLY WARMER HIGHS WITH H85
TEMPS AVERAGING +12C...IN THE LOW TO MID 70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGHLIGHTS...
* TEMPERATURES AT OR WARMER THAN NORMAL
* UNSETTLED BUT NOT A WASHOUT SUNDAY
* WIDESPREAD SHOWERS WITH LOCALLY HEAVY RAIN POSSIBLE MON/TUE
SYNOPTIC OVERVIEW...
A WARM FRONT WILL BE LIFTING NORTH THROUGH THE REGION SUNDAY AS ITS
PARENT LOW EXITS THE GREAT LAKES INTO ONTARIO. THE ATTENDING COLD
FRONT WILL BE PROGRESSIVE AND SWEEP ACROSS NEW ENGLAND SOMETIME
MON/TUE. THE FRONT WILL MOVE OFFSHORE LATER TUE WITH CONFLUENT FLOW
ALOFT AND HIGH PRES AT THE SURFACE BUILDING INTO NEW ENGLAND LATER
TUE INTO WED/THU. THIS MAY LEAVE THE REMNANTS OF TS KAREN MEANDERING
SOMEWHERE OVER THE SOUTHEAST STATES NEXT WEEK.
MODELS/GUIDANCE...
GOOD AGREEMENT ON THE OVERALL SYNOPTIC SCALE FLOW/FORECAST THEME.
00Z GFS/GEFS AND 12Z ECENS DISPLAY GOOD CLUSTERING ON POWERFUL
CLOSED MID LEVEL LOW OVER THE GREAT LAKES SUN NIGHT...THEN
DEAMPLIFYING AND BECOMING AN OPEN WAVE AS IT RACES ACROSS ONTARIO
AND QUEBEC MON. THIS RESULTS IN A PROGRESSIVE COLD FRONT CROSSING
NEW ENGLAND MON-TUE. THIS PROGRESSIVE NORTHERN STREAM SYSTEM RESULTS
IN AN UNPHASED SOLUTION WITH REMNANTS OF TS KAREN BEING LEFT BEHIND
ACROSS THE SOUTHEAST STATES EARLY NEXT WEEK. HOWEVER THE 00Z ECMWF
REMAINS MORE AMPLIFIED WITH THE GREAT LAKES MID LEVEL LOW WHICH
CAPTURES THE REMNANTS OF KAREN AND INGEST ITS MOISTURE PLUME INTO
THE FRONTAL BOUNDARY CROSSING NEW ENGLAND MON/TUE. HOWEVER ITS
SOLUTION TOO IS VERY PROGRESSIVE WITH ONLY A BRIEF PERIOD OF HEAVY
RAIN/SHOWERS SOMETIME MON/TUE. HOWEVER THE 00Z GFS/GEFS AND 12Z
ECENS ALL SUGGEST REMNANTS OF TS KAREN REMAINING WELL SOUTH OF NEW
ENGLAND. EITHER WAY NONE OF THE MODEL GUIDANCE SUPPORTS A HIGH
IMPACT/HEAVY RAINFALL EVENT FOR SOUTHERN NEW ENGLAND.
SENSIBLE WEATHER...
SAT NIGHT/SUNDAY...WARM FRONT LIFTS ACROSS AND NORTH OF THE REGION.
DEEP LAYER MOISTURE AND LIFT ARE LACKING SO THINKING ANY SHOWER
ACTIVITY WILL BE SPOTTY AND NOT WIDESPREAD. HENCE MANY HOURS OF DRY
WEATHER. COOLER AS WARM SECTOR MAY NOT OVERSPREAD THE REGION UNTIL
SUN NIGHT OR MON.
MON/TUE...A PERIOD OF SHOWERS WITH LOCALLY HEAVY RAIN APPEARS
LIKELY. DEPARTURE TIME OF SHOWERS STILL SOMEWHAT UNCERTAIN. MILD TO
WARM WITH FROPA NOT TIL LATE TUE OR TUE NIGHT.
WED/THU...UNCERTAINTY HERE BUT SOME MODEL CONSENSUS ON A DRYING
TREND WITH HIGH PRES BUILDING OVER NEW ENGLAND AND SUPPRESSING
REMNANTS OF TS KAREN WELL SOUTH OF NEW ENGLAND. IF THIS TREND
CONTINUES NEXT SHIFT MAY NEED TO LOWER POPS HERE. COOLER BUT
PROBABLY STILL NEAR OR SLIGHTLY WARMER THAN NORMAL.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE.
7 AM UPDATE...
NO CHANGE FROM PREVIOUS FORECAST. EARLIER DISCUSSION BELOW.
---------------------------------------------------------------
SOME SHOWERS POSSIBLE DURING THE DAY WITH A FOCUS ON WRN AND SRN
PORTIONS OF THE AREA. AN ISOLATED THUNDERSTORM IS ALSO POSSIBLE
THIS AFTERNOON/EVENING IN CT. MAINLY VFR IS EXPECTED TO PREVAIL
THROUGH THE PERIOD. THE ONLY CAVEAT WILL BE THE POTENTIAL FOR SOME
MVFR CIGS AND VSBYS WITH SOME OF THE -SHRA THIS AFTERNOON ALONG A
PSF- BAF/BDL- PVD LINE THIS AFTERNOON AND EVENING.
OTHERWISE...SOME BREAKS IN BOTH THE -SHRA AND CLOUDS OVERNIGHT
INTO SATURDAY.
KBOS TERMINAL...HIGH CONFIDENCE VFR. LIGHT WINDS SHIFT TO THE E
WITH A SEABREEZE THEN REMAIN MOSTLY E. THIS MAY INTRODUCE SOME LOW
CIGS LATE IN THE DAY/EVENING...BUT CONFIDENCE IS LOW.
KBDL TERMINAL...MAINLY VFR...BUT SOME MVFR CIGS POSSIBLE THIS
AFTERNOON. SCT SHOWERS THROUGH THE DAY TODAY. LOW PROB OF ISOLD
TSTM FRI AFTERNOON.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
MODERATE CONFIDENCE.
SAT NIGHT/SUN...VFR LIKELY WITH SPOTTY SHOWERS POSSIBLE.
MON/TUE...A PERIOD OF MVFR/IFR POSSIBLE IN SHOWERS WITH AN
APPROACHING COLD FRONT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SATURDAY/...HIGH CONFIDENCE.
EXPECT WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
SATURDAY. A FEW SHOWERS AND POSSIBLY EVEN A RUMBLE OF THUNDER MAY
AFFECT THE SOUTHERN WATERS THIS AFTERNOON AFTERNOON AND TONIGHT
WITH LOCAL VSBY RESTRICTIONS.
OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...
SAT NIGHT/SUN...LIGHT SE WINDS WITH HIGH PRES OVER THE MARITIMES.
SUN NIGHT/MON...INCREASING SSW WINDS WITH APPROACHING COLD FRONT.
VSBY LIMITED IN SHOWERS AND FOG.
MON NIGHT/TUE...COLD FRONTAL PASSAGE WITH REMNANTS OF TS KAREN
LIKELY REMAINING WELL SOUTH OF NEW ENGLAND.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/DOODY
NEAR TERM...NOCERA/DOODY
SHORT TERM...DOODY
LONG TERM...NOCERA
AVIATION...NOCERA/DOODY
MARINE...NOCERA/DOODY
AREA FORECAST DISCUSSION
NWS ALBANY NY
617 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM EDT...BANDS OF SHOWERS/STORMS HAS DEVELOPED ALONG AND
JUST NORTH OF THE I90 CORRIDOR PER THE LATEST RADAR SCANS THIS
MORNING. THE THETA-E ADVECTION WAS A TOUCH STRONGER AND FURTHER
NORTH PER THE HOURLY RUC13 ANALYSIS AND HAVE ADJUSTED THE
FORECAST/GRIDS ACCORDINGLY. OTHERWISE...FORECAST REMAINS IN PLACE
AS CLOUDS AND SHOWERS WILL CONTINUE TO OVERSPREAD THE CWFA THIS
MORNING.
PREV DISC...
SURFACE ANALYSIS HAS A WARM FRONT DRAPED ACROSS WESTERN NY INTO
CENTRAL PA AND OFF THE MID ATLANTIC COAST. IN THE UPPER
LEVELS...H2O VAPOR LOOP SHOWS A WEAK SHORT WAVE APPROACHING
WESTERN NY WHERE RUC13 ISENTROPIC ANALYSIS ON THE 300-305K SURFACE
REVEALS BROAD LIFT. REGIONAL RADARS CONFIRM THIS WITH SHOWERS AND
SOME THUNDERSTORMS /PER THE NLDN/ ACROSS THE MOHAWK VALLEY WITH
MORE CONCENTRATION OF ACTIVITY ACROSS WESTERN NY. TRENDS FOR THE
DAYLIGHT HOURS ARE FOR ADDITIONAL SHOWERS AND SOME THUNDERSTORMS
TO MOVE ACROSS THE REGION WITH THE BETTER CONCENTRATION ALONG THE
I90 CORRIDOR WHERE THE WARM FRONT IS FORECAST TO BE PLACED WITH
ADDITIONAL MID LEVEL INSTABILITY PER THE SHOWALTER VALUES AROUND
0C. THIS TOO IS SUGGESTED BY THE HRRR EXPERIENTIAL REFLECTIVITY
FORECASTS. WITH CONSIDERABLE CLOUD COVER EXPECTED...HAVE SHADED ON
THE COOLER SIDE OF THE GUIDANCE.
THE AFOREMENTIONED SHORT WAVE IS FORECAST TO EXIT OUR REGION BY
THIS EVENING. SOME RESIDUAL SHOWERS AND PERHAPS A RUMBLE OF
THUNDER ARE EXPECTED THROUGH EARLY THIS EVENING...THEN ISOLATED
ACTIVITY FOR THE REMAINDER OF THE OVERNIGHT PERIOD. WARM FRONT
WILL BE IN THE VICINITY OF THE REGION SO CLOUD COVER WILL LIKELY
BE IN PLACE AND POCKETS OF DRIZZLE AS THE LOWER LEVELS ARE
EXPECTED TO BE QUITE MOIST PER TH BUFR SOUNDINGS. LOW LEVEL FLOW
SLOWLY INCREASES FROM THE NORTH WHICH WILL PLAY HAVOC ON
TEMPERATURES TONIGHT. GUIDANCE NUMBERS ARE RATHER CLOSE AS WE
UTILIZED A BLENDED APPROACH. HOWEVER...IF THE DRAINAGE IS A BIT
STRONGER...THEN TEMPERATURES COULD BE A LITTLE COOLER.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
THE CENTRAL PLAINS STORM IS FORECAST TO BE QUITE MATURE AT THIS
TIME FRAME. MEANWHILE...THE WARM FRONT REMAINS IN THE VICINITY
WITH SOME TENDENCY TO SLIP A LITTLE FURTHER SOUTH AS HIGH PRESSURE
ACROSS SOUTHERN CANADA ATTEMPTS TO NOSE SOUTHWARD ACROSS OUR
REGION SATURDAY. EITHER WAY...CONSIDERABLE CLOUDINESS IS EXPECTED
AS LOWER LEVELS REMAIN QUITE MOIST ALONG WITH A SLIGHT CHANCE FOR
A SHOWER. WE WILL SHADE ON THE COOLER SIDE OF THE GUIDANCE
ENVELOPE AS THE LOW LEVEL NORTHERLY FLOW AND CLOUD COVER SHOULD
KEEP TEMPS INTO THE 60S FOR MOST LOCATIONS WITH LOWER 70S FOR THE
MID HUDSON VALLEY AND SOUTHERN LITCHFIELD COUNTY.
THE WARM FRONT WILL ATTEMPT TO SLOWLY LIFT NORTHWARD SATURDAY
NIGHT AND THROUGH SUNDAY. MOISTURE TRANSPORT AND ASSOCIATED LIFT
INCREASES TO OUR WEST AND NORTH WHERE WE WILL PLACE THE HIGHER
POPS. TEMPERATURES WILL BE RATHER STAGNATE AS SUGGESTED BY THE
GFS-MOS WITH NOT MUCH RANGE EXPECTED.
IT DOES SEEM WE WILL BECOME ENTRENCHED INTO THE WARM SECTOR DURING
SUNDAY BUT THE COMBINATION OF MARINE AIR INFLUENCE AND CLOUD COVER
THOSE H850 TEMPS INTO THE LOW-MID TEENS WILL NOT BE FULLY
REALIZED. THUS WE HAVE LOWERED HIGH TEMPERATURES A FEW DEGREES. AS
FOR PRECIP CHANCES...MAINLY TO OUR WEST AND NORTH ONCE AGAIN AND
AS THIS FRONT LIFTS FURTHER NORTH...SO WILL THE DECREASING
TENDENCY FOR SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED PERIOD WILL START OFF RATHER ACTIVE...BUT ANOTHER
EXTENDED PERIOD OF DRY AND MILD WEATHER WILL FOLLOW.
OUR REGION WILL BE IN A WARM SECTOR OF A FRONTAL SYSTEM ON SUNDAY
NIGHT. WITH PLENTY OF MOISTURE IN PLACE...THERE WILL BE A CHC FOR
RAIN SHOWERS ACROSS THE ENTIRE REGION. THE BEST CHC FOR RAIN SHOWERS
WILL BE ACROSS FAR NORTHWESTERN PARTS OF THE REGION...ESP TOWARDS
SUNRISE MONDAY. WITH A SOUTHERLY FLOW IN PLACE...IT WILL BE MILD
AND MUGGY...WITH MIN TEMPS IN THE MID 50S TO LOW 60S.
A STRONG COLD FRONT WILL BE MOVING ACROSS THE REGION SOMETIME MONDAY
INTO MONDAY EVENING. THE MODELS DON/T AGREE ON THE EXACT TIMING
RIGHT NOW...WITH THE 00Z GFS A LITTLE FASTER THAN THE 00Z ECMWF. BY
THIS POINT....NHC SHOWS THAT TC KAREN BE IN THE PROCESS OF
TRANSITIONING FROM A TROPICAL ENTITY...AND THE REMAINS LOOK TO BE
ABSORBED ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTH. STILL...A
STRONG LOW LEVEL JET OF 50-60 KTS WILL TRANSPORT PLENTY OF MOISTURE
UP ALONG THE FRONT FROM THE GULF OF MEXICO...WITH PWAT VALUES
EXCEEDING 1.50 INCHES ACROSS OUR REGION. WITH THE STRONG SFC
FORCING...A BAND OF LOCALLY HEAVY RAIN SHOWERS WILL BE POSSIBLE JUST
AHEAD AND ALONG THE FRONTAL BOUNDARY. ALONG WITH LIKELY POPS FOR
RAIN SHOWERS...WE WILL INCLUDE A SLIGHT CHC OF THUNDER...BUT
WIDESPREAD THUNDER DOESN/T APPEAR LIKELY DUE TO MEAGER AMOUNTS OF
INSTABILITY. IT WILL BE FAIRLY WARM ON MONDAY IN ADVANCE OF THE
FRONTAL BOUNDARY WITH MID 60S TO MID 70S ACROSS THE REGION. MIN
TEMPS WILL ON MONDAY NIGHT WILL BE COOLER THAN SUN NIGHT...BUT THE
EXACT TIMING WILL DEPEND JUST HOW MUCH COOLS OFF. FOR NOW...WE ARE
FORECASTING MIN TEMPS FROM THE LOW 40S IN THE DACKS TO THE MID 50S
IN THE MID HUDSON VALLEY AND NW CT.
WE WILL STILL ALLOW FOR A SHOWER ACROSS SOUTHERN AREAS TUESDAY
MORNING IN CASE THE FRONT SLOWS...OTHERWISE THE COLD FRONT SHOULD
HAVE PUSHED OFF TO OUR EAST BY TUESDAY...ALLOWING A DRIER AND
SOMEWHAT COOLER AIR MASS TO MOVE INTO OUR REGION. IT WILL BE DRY FOR
THE MID WEEK PERIOD /TUES AND WED/ WITH MAX TEMPS IN THE 60S...AND
LOWS IN THE 40S /SOME 30S ACROSS THE ADIRONDACKS AND SRN GREEN
MTNS/. THESE MAX TEMPS STILL LOOK A FEW DEGREES ABOVE NORMAL.
BY LATE IN THE WEEK...STRONG RIDGING WILL REESTABLISH ITSELF ALONG
THE EASTERN SEABOARD...AND EVEN MORE ABOVE NORMAL WARMTH WILL BE IN
PLACE FOR THURS/FRI. IT WILL CONTINUE TO BE DRY...WITH DAYTIME TEMPS
IN THE UPPER 60S TO MID 70S FOR VALLEY AREAS...AND MINS GENERALLY IN
THE MID 40S TO LOW 50S.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
A WARM FRONT IS SITUATED SOUTH OF THE REGION IS SLOWLY MOVING
NORTHWARD. OVC CIGS OF 4-6 KFT ARE IN PLACE ACROSS THE REGION.
REGIONAL MOSAIC RADAR SHOWS SOME SHOWERS WEST OF THE REGION...AND
THESE MAY AFFECT MAINLY THE NORTHERN SITES THROUGH THE MORNING
HOURS. WILL INCLUDE A VCSH AT ALL SITES WITH A TEMPO FOR MVFR
CIGS/VSBYS WITHIN RAIN SHOWERS FOR KALB/KGFL/KPSF. AT THIS
POINT...WIDESPREAD IFR CONDITIONS ARE NOT ANTICIPATED TODAY. LIGHT
AND VARIABLE WINDS ARE EXPECTED TODAY.
FLYING CONDITIONS WILL GENERALLY BE VFR DURING THE AFTN HOURS FOR
THE VALLEY TERMINALS...ALTHOUGH CIGS MAY REMAIN MVFR AT KPSF. WITH
LOW LEVEL MOISTURE REMAINING HIGH TONIGHT...ALL SITES LOOK TO HAVE
MVFR CIGS TONIGHT WITH MVFR BR POSSIBLE AT KPSF/KPOU AS WELL.
ALTHOUGH NOT AS WIDESPREAD AS THIS MORNING...STILL CANNOT RULE OUT A
SHOWER OR TWO THIS AFTERNOON INTO TONIGHT AS WELL. WINDS WILL BE
NEARLY CALM TONIGHT.
OUTLOOK...
SATURDAY-SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF
SHRA.
SUNDAY-MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
THE RH VALUES WILL FALL TO 50 TO 65 PERCENT THIS AFTERNOON...THEN
RECOVER TO 80 TO 100 PERCENT BY SATURDAY MORNING.
THE WINDS BECOME LIGHT TO CALM THIS MORNING AND SATURDAY
NIGHT...THEN BE FROM THE EAST TO NORTHEAST AT 5 TO 10 MPH DURING THE
DAYLIGHT HOURS TODAY.
A COLD FRONT WILL BRING WIDESPREAD SHOWERS TO THE REGION LATE
SUNDAY INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER
THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS
FOR EARLY OCTOBER.
THE DRY WEATHER STRETCH OVER THE PAST 10 DAYS OR SO WILL BE
COMING TO AN END AS A WARM FRONT APPROACHES ALONG WITH THE CHANCE
FOR SHOWERS FOR THE REMAINDER OF THIS WEEK AND INTO THE WEEKEND.
AT THIS TIME...QPF AMOUNTS RANGE FROM A TENTH OF AN INCH OVER THE
NRN PORTIONS OF THE HSA TO A THIRD OF AN INCH OVER THE SRN THIRD
FROM TONIGHT INTO SATURDAY MORNING.
THERE IS SIGNIFICANT UNCERTAINTY IN THE GUIDANCE IN THE TIMING
AND TRACK OF A STRONGER LOW PRESSURE SYSTEM AND ITS FRONTAL
BOUNDARY FOR LATE IN THE WEEKEND AND EARLY NEXT WEEK.
FURTHERMORE...WE CONTINUE TO MONITOR TRENDS ON THE TRACK OF TS
KAREN IN THE GULF OF MEXICO FROM THE GUIDANCE FROM THE NATIONAL
HURRICANE CENTER. THE AMOUNT OF RAINFALL VARIES GREATLY IN THE
GUIDANCE AT THIS TIME FOR PORTIONS OF EXTREME SRN NY AND NEW
ENGLAND EARLY IN THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...BGM
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
610 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM EDT...BANDS OF SHOWERS/STORMS HAS DEVELOPED ALONG AND
JUST NORTH OF THE I90 CORRIDOR PER THE LATEST RADAR SCANS THIS
MORNING. THE THETA-E ADVECTION WAS A TOUCH STRONGER AND FURTHER
NORTH PER THE HOURLY RUC13 ANALYSIS AND HAVE ADJUSTED THE
FORECAST/GRIDS ACCORDINGLY. OTHERWISE...FORECAST REMAINS IN PLACE
AS CLOUDS AND SHOWERS WILL CONTINUE TO OVERSPREAD THE CWFA THIS
MORNING.
PREV DISC...
SURFACE ANALYSIS HAS A WARM FRONT DRAPED ACROSS WESTERN NY INTO
CENTRAL PA AND OFF THE MID ATLANTIC COAST. IN THE UPPER
LEVELS...H2O VAPOR LOOP SHOWS A WEAK SHORT WAVE APPROACHING
WESTERN NY WHERE RUC13 ISENTROPIC ANALYSIS ON THE 300-305K SURFACE
REVEALS BROAD LIFT. REGIONAL RADARS CONFIRM THIS WITH SHOWERS AND
SOME THUNDERSTORMS /PER THE NLDN/ ACROSS THE MOHAWK VALLEY WITH
MORE CONCENTRATION OF ACTIVITY ACROSS WESTERN NY. TRENDS FOR THE
DAYLIGHT HOURS ARE FOR ADDITIONAL SHOWERS AND SOME THUNDERSTORMS
TO MOVE ACROSS THE REGION WITH THE BETTER CONCENTRATION ALONG THE
I90 CORRIDOR WHERE THE WARM FRONT IS FORECAST TO BE PLACED WITH
ADDITIONAL MID LEVEL INSTABILITY PER THE SHOWALTER VALUES AROUND
0C. THIS TOO IS SUGGESTED BY THE HRRR EXPERIENTIAL REFLECTIVITY
FORECASTS. WITH CONSIDERABLE CLOUD COVER EXPECTED...HAVE SHADED ON
THE COOLER SIDE OF THE GUIDANCE.
THE AFOREMENTIONED SHORT WAVE IS FORECAST TO EXIT OUR REGION BY
THIS EVENING. SOME RESIDUAL SHOWERS AND PERHAPS A RUMBLE OF
THUNDER ARE EXPECTED THROUGH EARLY THIS EVENING...THEN ISOLATED
ACTIVITY FOR THE REMAINDER OF THE OVERNIGHT PERIOD. WARM FRONT
WILL BE IN THE VICINITY OF THE REGION SO CLOUD COVER WILL LIKELY
BE IN PLACE AND POCKETS OF DRIZZLE AS THE LOWER LEVELS ARE
EXPECTED TO BE QUITE MOIST PER TH BUFR SOUNDINGS. LOW LEVEL FLOW
SLOWLY INCREASES FROM THE NORTH WHICH WILL PLAY HAVOC ON
TEMPERATURES TONIGHT. GUIDANCE NUMBERS ARE RATHER CLOSE AS WE
UTILIZED A BLENDED APPROACH. HOWEVER...IF THE DRAINAGE IS A BIT
STRONGER...THEN TEMPERATURES COULD BE A LITTLE COOLER.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
THE CENTRAL PLAINS STORM IS FORECAST TO BE QUITE MATURE AT THIS
TIME FRAME. MEANWHILE...THE WARM FRONT REMAINS IN THE VICINITY
WITH SOME TENDENCY TO SLIP A LITTLE FURTHER SOUTH AS HIGH PRESSURE
ACROSS SOUTHERN CANADA ATTEMPTS TO NOSE SOUTHWARD ACROSS OUR
REGION SATURDAY. EITHER WAY...CONSIDERABLE CLOUDINESS IS EXPECTED
AS LOWER LEVELS REMAIN QUITE MOIST ALONG WITH A SLIGHT CHANCE FOR
A SHOWER. WE WILL SHADE ON THE COOLER SIDE OF THE GUIDANCE
ENVELOPE AS THE LOW LEVEL NORTHERLY FLOW AND CLOUD COVER SHOULD
KEEP TEMPS INTO THE 60S FOR MOST LOCATIONS WITH LOWER 70S FOR THE
MID HUDSON VALLEY AND SOUTHERN LITCHFIELD COUNTY.
THE WARM FRONT WILL ATTEMPT TO SLOWLY LIFT NORTHWARD SATURDAY
NIGHT AND THROUGH SUNDAY. MOISTURE TRANSPORT AND ASSOCIATED LIFT
INCREASES TO OUR WEST AND NORTH WHERE WE WILL PLACE THE HIGHER
POPS. TEMPERATURES WILL BE RATHER STAGNATE AS SUGGESTED BY THE
GFS-MOS WITH NOT MUCH RANGE EXPECTED.
IT DOES SEEM WE WILL BECOME ENTRENCHED INTO THE WARM SECTOR DURING
SUNDAY BUT THE COMBINATION OF MARINE AIR INFLUENCE AND CLOUD COVER
...THOSE H850 TEMPS INTO THE LOW-MID TEENS WILL NOT BE FULLY
REALIZED. THUS WE HAVE LOWERED HIGH TEMPERATURES A FEW DEGREES. AS
FOR PRECIP CHANCES...MAINLY TO OUR WEST AND NORTH ONCE AGAIN AND
AS THIS FRONT LIFTS FURTHER NORTH...SO WILL THE DECREASING
TENDENCY FOR SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED PERIOD WILL START OFF RATHER ACTIVE...BUT ANOTHER
EXTENDED PERIOD OF DRY AND MILD WEATHER WILL FOLLOW.
OUR REGION WILL BE IN A WARM SECTOR OF A FRONTAL SYSTEM ON SUNDAY
NIGHT. WITH PLENTY OF MOISTURE IN PLACE...THERE WILL BE A CHC FOR
RAIN SHOWERS ACROSS THE ENTIRE REGION. THE BEST CHC FOR RAIN SHOWERS
WILL BE ACROSS FAR NORTHWESTERN PARTS OF THE REGION...ESP TOWARDS
SUNRISE MONDAY. WITH A SOUTHERLY FLOW IN PLACE...IT WILL BE MILD
AND MUGGY...WITH MIN TEMPS IN THE MID 50S TO LOW 60S.
A STRONG COLD FRONT WILL BE MOVING ACROSS THE REGION SOMETIME MONDAY
INTO MONDAY EVENING. THE MODELS DON/T AGREE ON THE EXACT TIMING
RIGHT NOW...WITH THE 00Z GFS A LITTLE FASTER THAN THE 00Z ECMWF. BY
THIS POINT....NHC SHOWS THAT TC KAREN BE IN THE PROCESS OF
TRANSITIONING FROM A TROPICAL ENTITY...AND THE REMAINS LOOK TO BE
ABSORBED ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTH. STILL...A
STRONG LOW LEVEL JET OF 50-60 KTS WILL TRANSPORT PLENTY OF MOISTURE
UP ALONG THE FRONT FROM THE GULF OF MEXICO...WITH PWAT VALUES
EXCEEDING 1.50 INCHES ACROSS OUR REGION. WITH THE STRONG SFC
FORCING...A BAND OF LOCALLY HEAVY RAIN SHOWERS WILL BE POSSIBLE JUST
AHEAD AND ALONG THE FRONTAL BOUNDARY. ALONG WITH LIKELY POPS FOR
RAIN SHOWERS...WE WILL INCLUDE A SLIGHT CHC OF THUNDER...BUT
WIDESPREAD THUNDER DOESN/T APPEAR LIKELY DUE TO MEAGER AMOUNTS OF
INSTABILITY. IT WILL BE FAIRLY WARM ON MONDAY IN ADVANCE OF THE
FRONTAL BOUNDARY WITH MID 60S TO MID 70S ACROSS THE REGION. MIN
TEMPS WILL ON MONDAY NIGHT WILL BE COOLER THAN SUN NIGHT...BUT THE
EXACT TIMING WILL DEPEND JUST HOW MUCH COOLS OFF. FOR NOW...WE ARE
FORECASTING MIN TEMPS FROM THE LOW 40S IN THE DACKS TO THE MID 50S
IN THE MID HUDSON VALLEY AND NW CT.
WE WILL STILL ALLOW FOR A SHOWER ACROSS SOUTHERN AREAS TUESDAY
MORNING IN CASE THE FRONT SLOWS...OTHERWISE THE COLD FRONT SHOULD
HAVE PUSHED OFF TO OUR EAST BY TUESDAY...ALLOWING A DRIER AND
SOMEWHAT COOLER AIR MASS TO MOVE INTO OUR REGION. IT WILL BE DRY FOR
THE MID WEEK PERIOD /TUES AND WED/ WITH MAX TEMPS IN THE 60S...AND
LOWS IN THE 40S /SOME 30S ACROSS THE ADIRONDACKS AND SRN GREEN
MTNS/. THESE MAX TEMPS STILL LOOK A FEW DEGREES ABOVE NORMAL.
BY LATE IN THE WEEK...STRONG RIDGING WILL REESTABLISH ITSELF ALONG
THE EASTERN SEABOARD...AND EVEN MORE ABOVE NORMAL WARMTH WILL BE IN
PLACE FOR THURS/FRI. IT WILL CONTINUE TO BE DRY...WITH DAYTIME TEMPS
IN THE UPPER 60S TO MID 70S FOR VALLEY AREAS...AND MINS GENERALLY IN
THE MID 40S TO LOW 50S.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
MID AND HIGH LEVEL CLOUDS ARE INCREASING ACROSS THE REGION AS A
WARM FRONT APPROACHES THE AREA. THE HIGH CLOUDS HAVE BEEN THIN
ENOUGH FOR TEMPS TO COOL RAPIDLY DOWN TO THE DEWPOINT AT
KGFL...WHICH HAS ALLOWED SOME IFR FOG TO DEVELOP THERE. PERIODS OF
IFR FOG WILL BE POSSIBLE THROUGH THE REMAINDER OF THE NIGHT AT
KGFL. OTHERWISE...INCREASING AMOUNTS OF CLOUDS SHOULD PREVENT
RADIATIONAL FOG FROM DEVELOPING FURTHER SOUTH AT KALB/KPSF/KPOU.
WINDS WILL BE CALM FOR THE REMAINDER OF THE OVERNIGHT HOURS.
ANY FOG WILL DISSIPATE AT KGFL BY AROUND SUNRISE. CLOUDS WILL
CONTINUE TO LOWER WITH BKN-OVC STRATUS CLOUDS AT 5-8 KFT. SOME
LIGHT RAIN SHOWERS WILL BE POSSIBLE BEGINNING IN THE MORNING
HOURS AS THE WARM FRONT GETS CLOSER. WE HAVE INCLUDED A VCSH AT
ALL SITES TO ACCOUNT FOR THIS POSSIBILITY. IT/S POSSIBLE THAT A
BRIEF PERIOD OF MVFR VSBYS/CIGS IS POSSIBLE WITHIN ANY RAIN
SHOWERS WITH THE PASSAGE OF THE WARM FRONT DURING THE DAY FRIDAY
INTO FRIDAY EVENING...BUT UNCERTAINTY REGARDING THE TIMING/EXTENT
OF THIS PREVENTS THE INCLUSION IN THE TAF AT THIS TIME...EXCEPT
FOR AT KPSF...WHERE MVFR CIGS ARE EXPECTED AFTER 16Z. CIGS MAY
LOWER TO AROUND 3500-5000 FT BY AFTERNOON HOURS FOR
KALB/KGFL/KPOU. LIGHT AND VARIABLE WINDS ARE EXPECTED DURING THE
DAY FRIDAY AND INTO FRIDAY EVENING.
OUTLOOK...
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY NIGHT TO SUNDAY: MODERATE OPERATIONAL IMPACT. SLIGHT
CHANCE OF SHRA.
SUNDAY NIGHT TO TUESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED
SHRA.
&&
.FIRE WEATHER...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
THE RH VALUES WILL FALL TO 50 TO 65 PERCENT THIS AFTERNOON...THEN
RECOVER TO 80 TO 100 PERCENT BY SATURDAY MORNING.
THE WINDS BECOME LIGHT TO CALM THIS MORNING AND SATURDAY
NIGHT...THEN BE FROM THE EAST TO NORTHEAST AT 5 TO 10 MPH DURING THE
DAYLIGHT HOURS TODAY.
A COLD FRONT WILL BRING WIDESPREAD SHOWERS TO THE REGION LATE
SUNDAY INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER
THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS
FOR EARLY OCTOBER.
THE DRY WEATHER STRETCH OVER THE PAST 10 DAYS OR SO WILL BE
COMING TO AN END AS A WARM FRONT APPROACHES ALONG WITH THE CHANCE
FOR SHOWERS FOR THE REMAINDER OF THIS WEEK AND INTO THE WEEKEND.
AT THIS TIME...QPF AMOUNTS RANGE FROM A TENTH OF AN INCH OVER THE
NRN PORTIONS OF THE HSA TO A THIRD OF AN INCH OVER THE SRN THIRD
FROM TONIGHT INTO SATURDAY MORNING.
THERE IS SIGNIFICANT UNCERTAINTY IN THE GUIDANCE IN THE TIMING
AND TRACK OF A STRONGER LOW PRESSURE SYSTEM AND ITS FRONTAL
BOUNDARY FOR LATE IN THE WEEKEND AND EARLY NEXT WEEK.
FURTHERMORE...WE CONTINUE TO MONITOR TRENDS ON THE TRACK OF TS
KAREN IN THE GULF OF MEXICO FROM THE GUIDANCE FROM THE NATIONAL
HURRICANE CENTER. THE AMOUNT OF RAINFALL VARIES GREATLY IN THE
GUIDANCE AT THIS TIME FOR PORTIONS OF EXTREME SRN NY AND NEW
ENGLAND EARLY IN THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...BGM
HYDROLOGY...BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS ALBANY NY
354 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS HAS A WARM FRONT DRAPED ACROSS WESTERN NY INTO
CENTRAL PA AND OFF THE MID ATLANTIC COAST. IN THE UPPER
LEVELS...H2O VAPOR LOOP SHOWS A WEAK SHORT WAVE APPROACHING
WESTERN NY WHERE RUC13 ISENTROPIC ANALYSIS ON THE 300-305K SURFACE
REVEALS BROAD LIFT. REGIONAL RADARS CONFIRM THIS WITH SHOWERS AND
SOME THUNDERSTORMS /PER THE NLDN/ ACROSS THE MOHAWK VALLEY WITH
MORE CONCENTRATION OF ACTIVITY ACROSS WESTERN NY. TRENDS FOR THE
DAYLIGHT HOURS ARE FOR ADDITIONAL SHOWERS AND SOME THUNDERSTORMS
TO MOVE ACROSS THE REGION WITH THE BETTER CONCENTRATION ALONG THE
I90 CORRIDOR WHERE THE WARM FRONT IS FORECAST TO BE PLACED WITH
ADDITIONAL MID LEVEL INSTABILITY PER THE SHOWALTER VALUES AROUND
0C. THIS TOO IS SUGGESTED BY THE HRRR EXPERIENTIAL REFLECTIVITY
FORECASTS. WITH CONSIDERABLE CLOUD COVER EXPECTED...HAVE SHADED ON
THE COOLER SIDE OF THE GUIDANCE.
THE AFOREMENTIONED SHORT WAVE IS FORECAST TO EXIT OUR REGION BY
THIS EVENING. SOME RESIDUAL SHOWERS AND PERHAPS A RUMBLE OF
THUNDER ARE EXPECTED THROUGH EARLY THIS EVENING...THEN ISOLATED
ACTIVITY FOR THE REMAINDER OF THE OVERNIGHT PERIOD. WARM FRONT
WILL BE IN THE VICINITY OF THE REGION SO CLOUD COVER WILL LIKELY
BE IN PLACE AND POCKETS OF DRIZZLE AS THE LOWER LEVELS ARE
EXPECTED TO BE QUITE MOIST PER TH BUFR SOUNDINGS. LOW LEVEL FLOW
SLOWLY INCREASES FROM THE NORTH WHICH WILL PLAY HAVOC ON
TEMPERATURES TONIGHT. GUIDANCE NUMBERS ARE RATHER CLOSE AS WE
UTILIZED A BLENDED APPROACH. HOWEVER...IF THE DRAINAGE IS A BIT
STRONGER...THEN TEMPERATURES COULD BE A LITTLE COOLER.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
THE CENTRAL PLAINS STORM IS FORECAST TO BE QUITE MATURE AT THIS
TIME FRAME. MEANWHILE...THE WARM FRONT REMAINS IN THE VICINITY
WITH SOME TENDENCY TO SLIP A LITTLE FURTHER SOUTH AS HIGH PRESSURE
ACROSS SOUTHERN CANADA ATTEMPTS TO NOSE SOUTHWARD ACROSS OUR
REGION SATURDAY. EITHER WAY...CONSIDERABLE CLOUDINESS IS EXPECTED
AS LOWER LEVELS REMAIN QUITE MOIST ALONG WITH A SLIGHT CHANCE FOR
A SHOWER. WE WILL SHADE ON THE COOLER SIDE OF THE GUIDANCE
ENVELOPE AS THE LOW LEVEL NORTHERLY FLOW AND CLOUD COVER SHOULD
KEEP TEMPS INTO THE 60S FOR MOST LOCATIONS WITH LOWER 70S FOR THE
MID HUDSON VALLEY AND SOUTHERN LITCHFIELD COUNTY.
THE WARM FRONT WILL ATTEMPT TO SLOWLY LIFT NORTHWARD SATURDAY
NIGHT AND THROUGH SUNDAY. MOISTURE TRANSPORT AND ASSOCIATED LIFT
INCREASES TO OUR WEST AND NORTH WHERE WE WILL PLACE THE HIGHER
POPS. TEMPERATURES WILL BE RATHER STAGNATE AS SUGGESTED BY THE
GFS-MOS WITH NOT MUCH RANGE EXPECTED.
IT DOES SEEM WE WILL BECOME ENTRENCHED INTO THE WARM SECTOR DURING
SUNDAY BUT THE COMBINATION OF MARINE AIR INFLUENCE AND CLOUD COVER
...THOSE H850 TEMPS INTO THE LOW-MID TEENS WILL NOT BE FULLY
REALIZED. THUS WE HAVE LOWERED HIGH TEMPERATURES A FEW DEGREES. AS
FOR PRECIP CHANCES...MAINLY TO OUR WEST AND NORTH ONCE AGAIN AND
AS THIS FRONT LIFTS FURTHER NORTH...SO WILL THE DECREASING
TENDENCY FOR SHOWERS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED PERIOD WILL START OFF RATHER ACTIVE...BUT ANOTHER
EXTENDED PERIOD OF DRY AND MILD WEATHER WILL FOLLOW.
OUR REGION WILL BE IN A WARM SECTOR OF A FRONTAL SYSTEM ON SUNDAY
NIGHT. WITH PLENTY OF MOISTURE IN PLACE...THERE WILL BE A CHC FOR
RAIN SHOWERS ACROSS THE ENTIRE REGION. THE BEST CHC FOR RAIN SHOWERS
WILL BE ACROSS FAR NORTHWESTERN PARTS OF THE REGION...ESP TOWARDS
SUNRISE MONDAY. WITH A SOUTHERLY FLOW IN PLACE...IT WILL BE MILD
AND MUGGY...WITH MIN TEMPS IN THE MID 50S TO LOW 60S.
A STRONG COLD FRONT WILL BE MOVING ACROSS THE REGION SOMETIME MONDAY
INTO MONDAY EVENING. THE MODELS DON/T AGREE ON THE EXACT TIMING
RIGHT NOW...WITH THE 00Z GFS A LITTLE FASTER THAN THE 00Z ECMWF. BY
THIS POINT....NHC SHOWS THAT TC KAREN BE IN THE PROCESS OF
TRANSITIONING FROM A TROPICAL ENTITY...AND THE REMAINS LOOK TO BE
ABSORBED ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTH. STILL...A
STRONG LOW LEVEL JET OF 50-60 KTS WILL TRANSPORT PLENTY OF MOISTURE
UP ALONG THE FRONT FROM THE GULF OF MEXICO...WITH PWAT VALUES
EXCEEDING 1.50 INCHES ACROSS OUR REGION. WITH THE STRONG SFC
FORCING...A BAND OF LOCALLY HEAVY RAIN SHOWERS WILL BE POSSIBLE JUST
AHEAD AND ALONG THE FRONTAL BOUNDARY. ALONG WITH LIKELY POPS FOR
RAIN SHOWERS...WE WILL INCLUDE A SLIGHT CHC OF THUNDER...BUT
WIDESPREAD THUNDER DOESN/T APPEAR LIKELY DUE TO MEAGER AMOUNTS OF
INSTABILITY. IT WILL BE FAIRLY WARM ON MONDAY IN ADVANCE OF THE
FRONTAL BOUNDARY WITH MID 60S TO MID 70S ACROSS THE REGION. MIN
TEMPS WILL ON MONDAY NIGHT WILL BE COOLER THAN SUN NIGHT...BUT THE
EXACT TIMING WILL DEPEND JUST HOW MUCH COOLS OFF. FOR NOW...WE ARE
FORECASTING MIN TEMPS FROM THE LOW 40S IN THE DACKS TO THE MID 50S
IN THE MID HUDSON VALLEY AND NW CT.
WE WILL STILL ALLOW FOR A SHOWER ACROSS SOUTHERN AREAS TUESDAY
MORNING IN CASE THE FRONT SLOWS...OTHERWISE THE COLD FRONT SHOULD
HAVE PUSHED OFF TO OUR EAST BY TUESDAY...ALLOWING A DRIER AND
SOMEWHAT COOLER AIR MASS TO MOVE INTO OUR REGION. IT WILL BE DRY FOR
THE MID WEEK PERIOD /TUES AND WED/ WITH MAX TEMPS IN THE 60S...AND
LOWS IN THE 40S /SOME 30S ACROSS THE ADIRONDACKS AND SRN GREEN
MTNS/. THESE MAX TEMPS STILL LOOK A FEW DEGREES ABOVE NORMAL.
BY LATE IN THE WEEK...STRONG RIDGING WILL REESTABLISH ITSELF ALONG
THE EASTERN SEABOARD...AND EVEN MORE ABOVE NORMAL WARMTH WILL BE IN
PLACE FOR THURS/FRI. IT WILL CONTINUE TO BE DRY...WITH DAYTIME TEMPS
IN THE UPPER 60S TO MID 70S FOR VALLEY AREAS...AND MINS GENERALLY IN
THE MID 40S TO LOW 50S.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
MID AND HIGH LEVEL CLOUDS ARE INCREASING ACROSS THE REGION AS A
WARM FRONT APPROACHES THE AREA. THE HIGH CLOUDS HAVE BEEN THIN
ENOUGH FOR TEMPS TO COOL RAPIDLY DOWN TO THE DEWPOINT AT
KGFL...WHICH HAS ALLOWED SOME IFR FOG TO DEVELOP THERE. PERIODS OF
IFR FOG WILL BE POSSIBLE THROUGH THE REMAINDER OF THE NIGHT AT
KGFL. OTHERWISE...INCREASING AMOUNTS OF CLOUDS SHOULD PREVENT
RADIATIONAL FOG FROM DEVELOPING FURTHER SOUTH AT KALB/KPSF/KPOU.
WINDS WILL BE CALM FOR THE REMAINDER OF THE OVERNIGHT HOURS.
ANY FOG WILL DISSIPATE AT KGFL BY AROUND SUNRISE. CLOUDS WILL
CONTINUE TO LOWER WITH BKN-OVC STRATUS CLOUDS AT 5-8 KFT. SOME
LIGHT RAIN SHOWERS WILL BE POSSIBLE BEGINNING IN THE MORNING
HOURS AS THE WARM FRONT GETS CLOSER. WE HAVE INCLUDED A VCSH AT
ALL SITES TO ACCOUNT FOR THIS POSSIBILITY. IT/S POSSIBLE THAT A
BRIEF PERIOD OF MVFR VSBYS/CIGS IS POSSIBLE WITHIN ANY RAIN
SHOWERS WITH THE PASSAGE OF THE WARM FRONT DURING THE DAY FRIDAY
INTO FRIDAY EVENING...BUT UNCERTAINTY REGARDING THE TIMING/EXTENT
OF THIS PREVENTS THE INCLUSION IN THE TAF AT THIS TIME...EXCEPT
FOR AT KPSF...WHERE MVFR CIGS ARE EXPECTED AFTER 16Z. CIGS MAY
LOWER TO AROUND 3500-5000 FT BY AFTERNOON HOURS FOR
KALB/KGFL/KPOU. LIGHT AND VARIABLE WINDS ARE EXPECTED DURING THE
DAY FRIDAY AND INTO FRIDAY EVENING.
OUTLOOK...
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SATURDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY NIGHT TO SUNDAY: MODERATE OPERATIONAL IMPACT. SLIGHT
CHANCE OF SHRA.
SUNDAY NIGHT TO TUESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED
SHRA.
&&
.FIRE WEATHER...
A WARM FRONT WILL LIFT SLOWLY NORTHWARD FROM THE LOWER
GREAT LAKES REGION AND THE MID ATLANTIC STATES. THIS FRONT WILL
PRODUCE SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER THROUGH
TODAY FROM THE MOHAWK VALLEY AND THE CAPITAL REGION SOUTH.
INCREASING HUMIDITY LEVELS...AND THE THREAT FOR ISOLATED TO
SCATTERED SHOWERS WILL CONTINUE THROUGH THE WEEKEND WITH THE
BOUNDARY IN THE VICINITY OF THE REGION.
THE RH VALUES WILL FALL TO 50 TO 65 PERCENT THIS AFTERNOON...THEN
RECOVER TO 80 TO 100 PERCENT BY SATURDAY MORNING.
THE WINDS BECOME LIGHT TO CALM THIS MORNING AND SATURDAY NIGHT...THEN BE
FROM THE EAST TO NORTHEAST AT 5 TO 10 MPH DURING THE DAYLIGHT
HOURS TODAY.
A COLD FRONT WILL BRING WIDESPREAD SHOWERS TO THE REGION LATE
SUNDAY INTO EARLY NEXT WEEK.
&&
.HYDROLOGY...
NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER
THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS
FOR EARLY OCTOBER.
THE DRY WEATHER STRETCH OVER THE PAST 10 DAYS OR SO WILL BE
COMING TO AN END AS A WARM FRONT APPROACHES ALONG WITH THE CHANCE
FOR SHOWERS FOR THE REMAINDER OF THIS WEEK AND INTO THE WEEKEND.
AT THIS TIME...QPF AMOUNTS RANGE FROM A TENTH OF AN INCH OVER THE
NRN PORTIONS OF THE HSA TO A THIRD OF AN INCH OVER THE SRN THIRD
FROM TONIGHT INTO SATURDAY MORNING.
THERE IS SIGNIFICANT UNCERTAINTY IN THE GUIDANCE IN THE TIMING
AND TRACK OF A STRONGER LOW PRESSURE SYSTEM AND ITS FRONTAL
BOUNDARY FOR LATE IN THE WEEKEND AND EARLY NEXT WEEK.
FURTHERMORE...WE CONTINUE TO MONITOR TRENDS ON THE TRACK OF TS
KAREN IN THE GULF OF MEXICO FROM THE GUIDANCE FROM THE NATIONAL
HURRICANE CENTER. THE AMOUNT OF RAINFALL VARIES GREATLY IN THE
GUIDANCE AT THIS TIME FOR PORTIONS OF EXTREME SRN NY AND NEW
ENGLAND EARLY IN THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...BGM
HYDROLOGY...BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
751 PM EDT THU OCT 3 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH WILL BEGIN TO SLOWLY LIFT BACK
ACROSS OUR AREA TONIGHT AND SLOWLY MAKE ITS WAY ACROSS THE AREA
THROUGH SUNDAY. MEANWHILE, A COLD FRONT WILL BEGIN TO APPROACH THE
AREA FROM THE WEST LATE SUNDAY INTO MONDAY. THIS BOUNDARY IS
EXPECTED TO SLOWLY MOVE ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS
THE REMNANTS OF TROPICAL STORM KAREN MOVES NORTHWARD ALONG THE
FRONTAL BOUNDARY. HIGH PRESSURE IS THEN EXPECTED TO BUILD BACK
ACROSS THE AREA FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WITH THE LATEST ESTF UPDATE, THE LARGEST ADJUSTMENT WAS TO LOWER
TEMPERATURES IN THE EASTERN PART OF OUR CWA AS ONSHORE FLOW HAS
DROPPED TEMPERATURES. FROM THERE DIFFERENCES WERE SMOOTHED TOWARD
CURRENT LOWS. BASED ON THE LATEST RAP AND HR3 (AND CURRENT RADAR),
WE DID MOVE UP POPS SLIGHTLY NWRN PART OF OUR CWA AS THE MODELS
HAVE SHOWERS TRYING TO GET THERE MOST OF THE NIGHT.
FOR TONIGHT, WINDS WILL REMAIN LIGHT, ALTHOUGH THE WASHED-OUT COLD
FRONT THAT WENT THROUGH LAST NIGHT WILL START TO REDEVELOP AND BEGIN
TRACKING BACK NORTH.
CLOUDS WILL BE ON THE INCREASE, ESPECIALLY NORTH AND WEST OF THE
I-95 CORRIDOR. SMALL POPS REMAIN IN THE GRIDS ACROSS THE POCONOS
AND THEN SPREAD SOUTHEAST DOWN TO THE DELAWARE VALLEY AROUND
DAYBREAK.
OVERNIGHT LOWS WILL MAINLY BE IN THE 50S TO AROUND 60, EXCEPT IN
CENTER CITY WHERE LOWER TO MIDDLE 60S ARE POSSIBLE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
THE WARM FRONT WILL CONTINUE ITS SLOW TRACK NORTHWARD DURING THE DAY
TOMORROW. POPS INCREASE TO HIGH CHANCE ACROSS OUR NORTHWESTERN ZONES
AND TO LOW CHANCE ACROSS THE I-95 CORRIDOR. WITH SOME INSTABILITY
PRESENT DURING THE AFTERNOON, A FEW THUNDERSTORMS CAN`T BE RULED
OUT. HIGHS WILL REACH THE LOW TO MID 80S ACROSS THE I-95 CORRIDOR
AND PORTIONS OF THE COASTAL PLAIN. RIGHT ALONG THE COAST AND ACROSS
THE NORTHWESTERN ZONES, TEMPERATURES WILL TOP OUT IN THE 70S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
THE WARM FRONT THAT STARTS TO LIFT ACROSS THE AREA THURSDAY NIGHT
INTO FRIDAY SHOULD CONTINUE TO SLOWLY LIFT THROUGH THE AREA SATURDAY
AND BE NORTH OF THE AREA BY SUNDAY. THERE IS A SMALL CHANCE FOR SOME
SHOWERS TO DEVELOP DURING THE DAY SATURDAY AND SUNDAY, MAINLY ACROSS
OUR NORTHERN AREAS CLOSER TO THE SLOW MOVING FRONTAL BOUNDARY. THERE
ARE NOT ANY STRONG SHORT WAVE/VORTICITY IMPULSES, BUT ANY WEAK
DISTURBANCE OR AFTERNOON INSTABILITY COULD HELP TRIGGER A FEW
SHOWERS, SO WE KEEP SLIGHT CHANCE POPS IN THE FORECAST.
BY SUNDAY NIGHT INTO MONDAY, A FRONTAL BOUNDARY WILL BE SLOWLY
MAKING ITS WAY TOWARD THE EASTERN SEABOARD WHILE THE FLOW ALOFT
BECOMES MORE SOUTHWEST. THIS SOUTHWEST FLOW WILL HELP SLOW THE
FRONTS PROGRESSION, IN ADDITION TO SENDING SEVERAL SHORT
WAVE/VORTICITY IMPULSES ACROSS THE AREA. PRECIPITATION CHANCES WILL
INCREASE STARTING SUNDAY NIGHT INTO MONDAY.
THEN THE FOCUS TURNS TO WHAT HAPPENS WITH THE REMNANTS OF WHAT IS
NOW TROPICAL STORM KAREN. THE LATEST NHC TRACK GUIDANCE WOULD BRING
THE REMNANTS OF THE STORM NEAR OUR SOUTHWESTERN AREAS BY TUESDAY
MORNING ALONG THE SLOW MOVING COLD FRONT. THIS WOULD HAVE THE
POTENTIAL TO BRING A PERIOD OF HEAVY RAINFALL TO THE AREA. WHILE THE
TRACK COULD STILL CHANGE OVER THE NEXT SEVERAL DAYS, WHICH WOULD
CHANGE THE AREAS WHERE HEAVIEST RAIN WOULD OCCUR, WE COULD STILL
EXPECT A WIDESPREAD 1 TO 2 INCHES OF RAINFALL, WITH A SWATH OF 2-4
INCHES POSSIBLE. WHILE IT HAS BEEN RATHER DRY THE LAST WEEK OR
TWO, IF WE GET ENOUGH HEAVY RAINFALL IN A SHORT PERIOD OF TIME,
THERE IS THE POTENTIAL FOR SOME FLOODING TO OCCUR EARLY NEXT WEEK.
ONCE THE REMNANT LOW PASSES OUR AREA, THE FRONT WILL CONTINUE TO
SLOWLY SLIDE OFF TO THE EAST THROUGH TUESDAY AND INTO WEDNESDAY. THE
PRECIPITATION MAY ACTUALLY COME TO AN END BY TUESDAY AFTERNOON AS
THE BRUNT OF THE MOISTURE PULLS AWAY WITH THE LOW. HIGH PRESSURE
IS THEN EXPECTED TO BUILD BACK ACROSS THE AREA FOR WEDNESDAY INTO
THURSDAY, WHICH SHOULD ONCE AGAIN PROVIDE A DRYING OUT PERIOD. THE
ECMWF TRIES TO DEVELOP A CLOSED LOW AND MOVE IT ACROSS THE AREA
DURING THIS PERIOD, WHICH WOULD BRING CONTINUES WET WEATHER; FOR
NOW WE HAVE NOT BOUGHT INTO THIS SINCE THE 00Z RUN HAD A RIDGE
DEVELOPING ACROSS THE AREA...
WITH THICKNESSES RISING SATURDAY THEN REMAINING NEARLY STEADY
THROUGH SUNDAY, TEMPERATURES WILL RISE SEVERAL DEGREES ABOVE NORMAL
FOR THE WEEKEND. AS CLOUD COVER AND RAINFALL RETURN FOR MONDAY, THEN
THE FRONT PASSES BY TUESDAY, TEMPERATURES ARE EXPECTED TOO COOL OFF
FOR MUCH OF NEXT WEEK.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LOWER CONFIDENCE THAN AVERAGE ON THE 00Z TAFS WITH RESPECT TO FOG
POTENTIAL TOWARD MORNING.
FOR THIS EVENING VFR CONDITIONS, LIGHT SOUTHWEST WINDS AND PLENTY
OF HIGH LEVEL CLOUDINESS INTERSPERSED WITH SOME MID LEVEL CLOUDS.
OVERNIGHT, DEBRIS MID AND HIGH LEVEL CLOUDINESS FROM PCPN IN
WESTERN PA SHOULD MOVE ACROSS. THIS IS WORKING IN CONFLICT WITH
THE HIGHER DEW POINTS AS TO HOW MUCH FOG WILL FORM. THE TAFS SIDED
WITH THE CLOUDS MAKING IT MORE DIFFICULT FOR FOG TO FORM AND WE
DID NOT LOWER OUTLYING AIRPORTS AS DEEP INTO MVFR AND IFR
TERRITORY AS OCCURRED THIS MORNING. COMMISERATE WITH THE FOG
POTENTIAL ANY WINDS WILL BE VERY LIGHT.
FOG IS FORECAST TO BE GONE BY 13Z FRIDAY AT WHICH TIME A LIGHT SW
WIND OF AROUND 5 KNOTS SHOULD START. MID LEVEL VFR CIGS EXPECTED.
FRIDAY AFTERNOON, FRONTAL BOUNDARY MAY TRIGGER SOME MVFR LEVEL
SHOWERS OR TSTMS. GREATEST COVERAGE AND CONFIDENCE IS AT NORTHERN
TERMINALS AND AIRPORTS. TSTM COVERAGE TOO ISOLATED AT THIS
FORECAST JUNCTURE TO INCLUDE. SOUTHWEST WINDS SHOULD INCREASE TO
CLOSE TO 10 KNOTS.
A SEA BREEZE FRONT SHOULD FORM ACROSS THE EASTERN COUNTIES OF NJ
AND DELAWARE AND COME CLOSE TO KACY DURING THE SECOND HALF OF THE
AFTERNOON.
OUTLOOK...
SATURDAY-SUNDAY...MOSTLY VFR EXCEPT POSSIBLE OVERNIGHT/MORNING FOG.
THERE IS A SMALL CHANCE OF SHOWERS OVER THE WEEKEND, MAINLY ON
SATURDAY FOR NORTHERN AREAS.
SUNDAY NIGHT-TUESDAY...INCREASING CHANCE OF MVFR/IFR CIGS AND VSBYS
WITH POSSIBLE HEAVY RAIN. A RETURN TO VFR EXPECTED TUESDAY
AFTERNOON/NIGHT.
WEDNESDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WITH HARDLY ANY GRADIENT THIS AFTERNOON, WINDS ARE LIGHT AND
VARIABLE. WINDS AT BUOY 44065 WINDS ARE SOUTH, AND AT 44025,
WINDS HAVE A WESTERLY COMPONENT.
FOR TONIGHT AND THROUGH TOMORROW, THE WINDS WILL REMAIN LIGHT, BUT
SHOULD TAKE ON A MORE SOUTH TO SOUTHWEST DIRECTION. AND WITH SEAS
RELATIVELY CALM, HEADLINES AREN`T NEEDED.
THE NORTHERN WATERS COULD SEE A SHOWER OR THUNDERSTORM TOMORROW
AFTERNOON.
OUTLOOK...
CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS SATURDAY
INTO SUNDAY AS HIGH PRESSURE REMAINS OVER THE OCEAN; ALTHOUGH WINDS
MAY PERIODICALLY GUST AROUND 15-20 KNOTS. VARYING WIND DIRECTIONS
CAN BE EXPECTED AS A WARM FRONT WILL BE LIFTING THROUGH THE WATERS
OVER THE WEEKEND. AS THE BOUNDARY MOVES WELL NORTH OF THE AREA BY
SUNDAY NIGHT, WINDS AND SEAS COULD APPROACH ADVISORY LEVELS LATE
SUNDAY INTO MONDAY. A COLD FRONT WILL BE APPROACHING THE AREA
MONDAY, WHILE THE REMNANTS OF TROPICAL STORM KAREN MOVES NORTH
ALONG THE EASTERN SEABOARD. THIS COULD BRING A PERIOD OF STRONG
WINDS AND HEAVY RAIN TO THE WATERS LATE MONDAY INTO TUESDAY.
&&
.CLIMATE...
TODAY WAS A RATHER WARM DAY ACROSS THE REGION. HOWEVER WE DID NOT
REACH RECORD HIGH TEMPERATURES AT ANY OF OUR CLIMATE SITES FALLING
SEVERAL DEGREES SHORT. THE RECORDS FOR TODAY WERE
90 DEGREES AT PHL AND ACY SET BACK IN 1919
88 DEGREES AT RDG AND ILG BACK IN 1919
88 DEGREES AT TTN IN 1898
88 DEGREES AT GED IN 2002
83 DEGREES AT ABE IN 2007
80 DEGREES AT MPO IN 1919
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...GIGI/KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...ROBERTSON
AVIATION...GIGI/ROBERTSON
MARINE...KRUZDLO/ROBERTSON
CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
556 PM EDT THU OCT 3 2013
.SYNOPSIS...
A FRONTAL BOUNDARY TO OUR SOUTH WILL BEGIN TO SLOWLY LIFT BACK
ACROSS OUR AREA TONIGHT AND SLOWLY MAKE ITS WAY ACROSS THE AREA
THROUGH SUNDAY. MEANWHILE, A COLD FRONT WILL BEGIN TO APPROACH THE
AREA FROM THE WEST LATE SUNDAY INTO MONDAY. THIS BOUNDARY IS
EXPECTED TO SLOWLY MOVE ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS
THE REMNANTS OF TROPICAL STORM KAREN MOVES NORTHWARD ALONG THE
FRONTAL BOUNDARY. HIGH PRESSURE IS THEN EXPECTED TO BUILD BACK
ACROSS THE AREA FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WITH THE LATEST ESTF UPDATE, THE LARGEST ADJUSTMENT WAS TO LOWER
TEMPERATURES IN THE EASTERN PART OF OUR CWA AS ONSHORE FLOW HAS
DROPPED TEMPERATURES. FROM THERE DIFFERENCES WERE SMOOTHED TOWARD
CURRENT LOWS. BASED ON THE LATEST RAP AND HR3 (AND CURRENT RADAR),
WE DID MOVE UP POPS SLIGHTLY NWRN PART OF OUR CWA AS THE MODELS
HAVE SHOWERS TRYING TO GET THERE MOST OF THE NIGHT.
FOR TONIGHT, WINDS WILL REMAIN LIGHT, ALTHOUGH THE WASHED-OUT COLD
FRONT THAT WENT THROUGH LAST NIGHT WILL START TO REDEVELOP AND BEGIN
TRACKING BACK NORTH.
CLOUDS WILL BE ON THE INCREASE, ESPECIALLY NORTH AND WEST OF THE
I-95 CORRIDOR. SMALL POPS REMAIN IN THE GRIDS ACROSS THE POCONOS
AND THEN SPREAD SOUTHEAST DOWN TO THE DELAWARE VALLEY AROUND
DAYBREAK.
OVERNIGHT LOWS WILL MAINLY BE IN THE 50S TO AROUND 60, EXCEPT IN
CENTER CITY WHERE LOWER TO MIDDLE 60S ARE POSSIBLE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
THE WARM FRONT WILL CONTINUE ITS SLOW TRACK NORTHWARD DURING THE DAY
TOMORROW. POPS INCREASE TO HIGH CHANCE ACROSS OUR NORTHWESTERN ZONES
AND TO LOW CHANCE ACROSS THE I-95 CORRIDOR. WITH SOME INSTABILITY
PRESENT DURING THE AFTERNOON, A FEW THUNDERSTORMS CAN`T BE RULED
OUT. HIGHS WILL REACH THE LOW TO MID 80S ACROSS THE I-95 CORRIDOR
AND PORTIONS OF THE COASTAL PLAIN. RIGHT ALONG THE COAST AND ACROSS
THE NORTHWESTERN ZONES, TEMPERATURES WILL TOP OUT IN THE 70S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
THE WARM FRONT THAT STARTS TO LIFT ACROSS THE AREA THURSDAY NIGHT
INTO FRIDAY SHOULD CONTINUE TO SLOWLY LIFT THROUGH THE AREA SATURDAY
AND BE NORTH OF THE AREA BY SUNDAY. THERE IS A SMALL CHANCE FOR SOME
SHOWERS TO DEVELOP DURING THE DAY SATURDAY AND SUNDAY, MAINLY ACROSS
OUR NORTHERN AREAS CLOSER TO THE SLOW MOVING FRONTAL BOUNDARY. THERE
ARE NOT ANY STRONG SHORT WAVE/VORTICITY IMPULSES, BUT ANY WEAK
DISTURBANCE OR AFTERNOON INSTABILITY COULD HELP TRIGGER A FEW
SHOWERS, SO WE KEEP SLIGHT CHANCE POPS IN THE FORECAST.
BY SUNDAY NIGHT INTO MONDAY, A FRONTAL BOUNDARY WILL BE SLOWLY
MAKING ITS WAY TOWARD THE EASTERN SEABOARD WHILE THE FLOW ALOFT
BECOMES MORE SOUTHWEST. THIS SOUTHWEST FLOW WILL HELP SLOW THE
FRONTS PROGRESSION, IN ADDITION TO SENDING SEVERAL SHORT
WAVE/VORTICITY IMPULSES ACROSS THE AREA. PRECIPITATION CHANCES WILL
INCREASE STARTING SUNDAY NIGHT INTO MONDAY.
THEN THE FOCUS TURNS TO WHAT HAPPENS WITH THE REMNANTS OF WHAT IS
NOW TROPICAL STORM KAREN. THE LATEST NHC TRACK GUIDANCE WOULD BRING
THE REMNANTS OF THE STORM NEAR OUR SOUTHWESTERN AREAS BY TUESDAY
MORNING ALONG THE SLOW MOVING COLD FRONT. THIS WOULD HAVE THE
POTENTIAL TO BRING A PERIOD OF HEAVY RAINFALL TO THE AREA. WHILE THE
TRACK COULD STILL CHANGE OVER THE NEXT SEVERAL DAYS, WHICH WOULD
CHANGE THE AREAS WHERE HEAVIEST RAIN WOULD OCCUR, WE COULD STILL
EXPECT A WIDESPREAD 1 TO 2 INCHES OF RAINFALL, WITH A SWATH OF 2-4
INCHES POSSIBLE. WHILE IT HAS BEEN RATHER DRY THE LAST WEEK OR
TWO, IF WE GET ENOUGH HEAVY RAINFALL IN A SHORT PERIOD OF TIME,
THERE IS THE POTENTIAL FOR SOME FLOODING TO OCCUR EARLY NEXT WEEK.
ONCE THE REMNANT LOW PASSES OUR AREA, THE FRONT WILL CONTINUE TO
SLOWLY SLIDE OFF TO THE EAST THROUGH TUESDAY AND INTO WEDNESDAY. THE
PRECIPITATION MAY ACTUALLY COME TO AN END BY TUESDAY AFTERNOON AS
THE BRUNT OF THE MOISTURE PULLS AWAY WITH THE LOW. HIGH PRESSURE
IS THEN EXPECTED TO BUILD BACK ACROSS THE AREA FOR WEDNESDAY INTO
THURSDAY, WHICH SHOULD ONCE AGAIN PROVIDE A DRYING OUT PERIOD. THE
ECMWF TRIES TO DEVELOP A CLOSED LOW AND MOVE IT ACROSS THE AREA
DURING THIS PERIOD, WHICH WOULD BRING CONTINUES WET WEATHER; FOR
NOW WE HAVE NOT BOUGHT INTO THIS SINCE THE 00Z RUN HAD A RIDGE
DEVELOPING ACROSS THE AREA...
WITH THICKNESSES RISING SATURDAY THEN REMAINING NEARLY STEADY
THROUGH SUNDAY, TEMPERATURES WILL RISE SEVERAL DEGREES ABOVE NORMAL
FOR THE WEEKEND. AS CLOUD COVER AND RAINFALL RETURN FOR MONDAY, THEN
THE FRONT PASSES BY TUESDAY, TEMPERATURES ARE EXPECTED TOO COOL OFF
FOR MUCH OF NEXT WEEK.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS WILL PREVAIL THROUGH THE EVENING HOURS. BUT WITH
LIGHT WINDS AND DEWPOINTS IN THE 50S TO MID 60S, EITHER FOG OR HAZE
SHOULD DEVELOP AFTER MIDNIGHT. FOR THE CLIMATOLOGICALLY FAVORED
TERMINALS, MVFR WITH A TEMPO IFR IS FORECAST TOWARD DAYBREAK.
ELSEWHERE, SOME MVFR SHOULD BE ANTICIPATED.
WINDS WILL BE QUITE LIGHT TONIGHT. PROBABLY CALM AT A FEW TERMINALS.
DIRECTION-WISE, FOR THOSE POSTING A SPEED, WINDS WILL BE OUT OF THE
SOUTH OR SOUTHWEST.
PROB30`S HAVE BEEN INCLUDED TOMORROW STARTING AT 14Z FOR KABE AND
KRDG AND AT 20Z FOR KPHL. ALL WINDS WILL BE LESS THAN 10 KT AND
MAINLY FROM THE SOUTH OR SOUTHWEST.
OUTLOOK...
SATURDAY-SUNDAY...MOSTLY VFR EXCEPT POSSIBLE OVERNIGHT/MORNING FOG.
THERE IS A SMALL CHANCE OF SHOWERS OVER THE WEEKEND, MAINLY ON
SATURDAY FOR NORTHERN AREAS.
SUNDAY NIGHT-TUESDAY...INCREASING CHANCE OF MVFR/IFR CIGS AND VSBYS
WITH POSSIBLE HEAVY RAIN. A RETURN TO VFR EXPECTED TUESDAY
AFTERNOON/NIGHT.
WEDNESDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
WITH HARDLY ANY GRADIENT THIS AFTERNOON, WINDS ARE LIGHT AND
VARIABLE. WINDS AT BUOY 44065 WINDS ARE SOUTH, AND AT 44025,
WINDS HAVE A WESTERLY COMPONENT.
FOR TONIGHT AND THROUGH TOMORROW, THE WINDS WILL REMAIN LIGHT, BUT
SHOULD TAKE ON A MORE SOUTH TO SOUTHWEST DIRECTION. AND WITH SEAS
RELATIVELY CALM, HEADLINES AREN`T NEEDED.
THE NORTHERN WATERS COULD SEE A SHOWER OR THUNDERSTORM TOMORROW
AFTERNOON.
OUTLOOK...
CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS SATURDAY
INTO SUNDAY AS HIGH PRESSURE REMAINS OVER THE OCEAN; ALTHOUGH WINDS
MAY PERIODICALLY GUST AROUND 15-20 KNOTS. VARYING WIND DIRECTIONS
CAN BE EXPECTED AS A WARM FRONT WILL BE LIFTING THROUGH THE WATERS
OVER THE WEEKEND. AS THE BOUNDARY MOVES WELL NORTH OF THE AREA BY
SUNDAY NIGHT, WINDS AND SEAS COULD APPROACH ADVISORY LEVELS LATE
SUNDAY INTO MONDAY. A COLD FRONT WILL BE APPROACHING THE AREA
MONDAY, WHILE THE REMNANTS OF TROPICAL STORM KAREN MOVES NORTH
ALONG THE EASTERN SEABOARD. THIS COULD BRING A PERIOD OF STRONG
WINDS AND HEAVY RAIN TO THE WATERS LATE MONDAY INTO TUESDAY.
&&
.CLIMATE...
TODAY WAS A RATHER WARM DAY ACROSS THE REGION. HOWEVER WE DID NOT
REACH RECORD HIGH TEMPERATURES AT ANY OF OUR CLIMATE SITES FALLING
SEVERAL DEGREES SHORT. THE RECORDS FOR TODAY WERE
90 DEGREES AT PHL AND ACY SET BACK IN 1919
88 DEGREES AT RDG AND ILG BACK IN 1919
88 DEGREES AT TTN IN 1898
88 DEGREES AT GED IN 2002
83 DEGREES AT ABE IN 2007
80 DEGREES AT MPO IN 1919
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...GIGI/KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...ROBERTSON
AVIATION...KRUZDLO/ROBERTSON
MARINE...KRUZDLO/ROBERTSON
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
440 AM EDT THU OCT 3 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE FIRST SIGNS IN THE
NORTHERN STREAM OF A SIGNIFICANT AMPLIFICATION THAT WILL TAKE PLACE
OVER THE WESTERN AND CENTRAL CONUS DURING THE NEXT 48-60 HOURS. THE
EXTENT OF THIS EVOLVING TROUGH SHOULD BE ENOUGH TO BRING THE FIRST
SUBSTANTIAL SNOWFALLS OF THE SEASON TO PARTS OF THE INTER-MOUNTAIN
WEST AND NORTHERN PLAINS STATES. THAT IS HOWEVER FAR FROM US...AND
FAR FROM OUR FORECAST THE NEXT FEW DAYS. IN FACT...THE SIGNIFICANT
HEIGHT FALLS OVER THE WESTERN HALF OF THE CONUS WILL FORCE A RIDGE
AMPLIFICATION ALONG THE EASTERN SEABOARD INTO THE UPCOMING WEEKEND.
THE ONE...SOMEWHAT BIG...ISSUE EVEN WITH THE BUILDING RIDGE IS THAT
"NOT SO LITTLE" DISTURBANCE EMERGING THROUGH THE YUCATAN CHANNEL
INTO THE SOUTHERN GULF OF MEXICO EARLY THIS MORNING. AS OF THE
WRITING OF THIS DISCUSSION...THE NATIONAL HURRICANE CENTER GIVES
THIS SYSTEM A HIGH 80% CHANCE OF TROPICAL DEVELOPMENT WITHIN THE
NEXT 48 HOURS. ONCE AGAIN...TROPICAL DEVELOPMENT MEANS AT LEAST
REACHING DEPRESSION STATUS. EARLY MORNING SATELLITE IMAGERY
CERTAINLY SHOWS A LARGE MASS OF THUNDERSTORMS AND COLD CLOUD TOPS
(<-80C) ON THE EASTERN SIDE OF THIS DISTURBANCE. HOWEVER...THE LAST
FLIGHT DOWN TO THE DISTURBANCE DID NOT FIND ALL THAT ORGANIZED A
SURFACE REFLECTION YET.
ALL THAT BEING SAID...THERE ARE STILL NO RELIABLE GUIDANCE MEMBERS
THAT BRING THIS SYSTEM TOWARD OUR COASTLINE. HOWEVER...ALTHOUGH
MODELS SUCH AS THE 03/00Z GFS ARE CLOSE ENOUGH THAT IF DEVELOPMENT
DID OCCUR...WE WOULD BE DEALING WITH SOME FRINGE EFFECTS OVER THE
COASTAL WATERS WITH ELEVATED WAVES...AND THE POTENTIAL FOR ELEVATED
RIP CURRENT RISK ALONG AREA BEACHES BY THE TIME THE WEEKEND ARRIVES.
WE WILL BE CLOSELY MONITORING THE PROGRESS OF THIS SYSTEM.
AT THE SURFACE...FORECAST AREA RESIDES IN A BROAD EASTERLY FLOW
PATTERN BETWEEN THE ABOVE MENTIONED LOW NEAR THE YUCATAN
CHANNEL...AND 1020MB HIGH PRESSURE OVER THE MID-ATLANTIC STATES AND
CAROLINAS. DRY CONDITIONS OUT THERE EARLY THIS MORNING WITH REGIONAL
RADARS SHOWING ONLY A FEW RETURNS WELL OUT INTO THE GULF. THE DRY
AND QUIET CONDITIONS SHOULD BE WITH US THROUGH THE MAJORITY OF THE
MORNING.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
THE SAME FORECAST ISSUES EXIST TONIGHT THAT EXISTED 24 HOURS AGO...
PRIMARILY RELATED TO THE POTENTIAL TROPICAL DEVELOPMENT IN THE
CENTRAL GULF AND DIFFERENCES IN ITS EVOLUTION BETWEEN GUIDANCE
MEMBERS. THERE IS AT LEAST SOME BETTER AGREEMENT IN A MORE
CONSOLIDATED SYSTEM MOVING NORTHWARD...BUT JUST WHAT PART OF THE
NORTHERN GULF COAST THE MAIN VORTICITY CENTER WILL MOVE TOWARD IS
STILL A BIT UP IN THE AIR. SIMILAR TO LAST NIGHT...USED PRIMARILY
THE SREF MEAN TO FORECAST ELEMENTS RELATED TO THE MASS FIELDS...BUT
ALSO GAVE SOME CONSIDERATION TO THE GFS AS IT BRINGS THE LOW
CLOSEST...YET STILL TO THE WEST OF OUR FORECAST AREA. AS WAS
MENTIONED ABOVE...ANY IMPACTS FROM THIS SYSTEM (IF ANY) LOOK LIKE
THEY WOULD BE MARINE RELATED...WITH NOT MUCH TO SPEAK OF FOR THE
LAND ZONES.
TODAY/TONIGHT...EXPECTING A SIMILAR PATTERN TO WHAT WAS EXPERIENCED
ON WEDNESDAY...AND HENCE THE FORECAST IS SIMILAR. THE MORNING HOURS
WILL BE QUIET AND DRY WITH FILTERED SUN THROUGH PERIODS OF HIGH
CLOUDS. A SIGNIFICANT PLUME OF COLUMN MOISTURE IS STILL IN PLACE
OVER THE EASTERN GULF OF MEXICO AND SOUTHWEST FLORIDA. AS THE DAY
PROGRESSES INTO THE AFTERNOON...THE COMBINATION OF DIURNAL
HEATING...DEEP MOISTURE AND SOME ENHANCED CONVERGENCE NEAR THE
COAST AS THE GRADIENT SLACKENS OVER THE NEAR-SHORE WATERS WILL
COMBINE TO FORCE A SCATTERING OF SHOWERS TO THE SOUTH OF TAMPA BAY.
THE BEST CHANCE OF THE SHOWERS WILL BE ALONG THE I-75 CORRIDOR AND
WEST TO THE COAST WHERE THE GRIDS SHOW A 40-60% CHANCE OF SEEING AN
LATE DAY SHOWER OR STORM. RAIN CHANCES WILL QUICKLY DECREASE THE
FURTHER NORTH AND INLAND ONE TRAVELS FROM THE SUNCOAST...AND
CURRENTLY HAVE LITTLE IF ANY CHANCE OF RAIN ALONG AND NORTH OF THE
I-4 CORRIDOR. ANY EVENING SHOWERS SHOULD PROGRESS OFFSHORE BY
MIDNIGHT AS THE EASTERLY FLOW AGAIN BECOMES STEADY. ANOTHER
GENERALLY QUIET AND DRY OVERNIGHT PERIOD IS FORECAST UNDER PASSING
BANDS OF MID/UPPER LEVEL CLOUDS.
FRIDAY THROUGH SATURDAY...WILL BE WATCHING THE POTENTIAL FOR A
TROPICAL SYSTEM TO BE MOVING NORTHWARD THROUGH THE CENTRAL GULF TO
OUR WEST. THE EXACT EVOLUTION OF THIS SYSTEM WILL HAVE A BIG
INFLUENCE ON THE FORECAST DETAILS FOR OUR AREA RELATED TO GRADIENT
AND RAIN CHANCES. A STRONGER SYSTEM OVER THE CENTRAL GULF...COULD IN
FACT HELP KEEP US DRIER AS THE GRADIENT WOULD BE TIGHTER AND LESSEN
AFTERNOON COASTAL CONVERGENCE...AND ALSO ENHANCE SUPPRESSION
OVERHEAD ON THE PERIPHERY OF THE CIRCULATION. WITH SO MUCH
UNCERTAINLY AT THIS TIME...KEPT THE FORECAST BROAD...SHOWING A
CHANCE FOR AFTERNOON SHOWERS AND SEASONABLE TEMPS. EVEN IF WE DO SEE
SCT SHOWERS...FRIDAY AND SATURDAY WILL NOT BE WET DAYS...WITH A
MAJORITY OF THE TIME RAIN-FREE. DEPENDING ON THE TRACK AND STRENGTH
OF THE SYSTEM...SATURDAY INTO SUNDAY WOULD BE WHEN ENHANCED
SWELL/SURF ALONG OUR BEACHES COULD ELEVATED THE RISK FOR MORE
FREQUENT/STRONGER RIP CURRENTS. WE WILL BE WATCHING THIS POTENTIAL
CLOSELY.
&&
.LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)...
THE PERIOD BEGINS WITH LOW PRESSURE SYSTEM SOMEWHERE ON THE GULF
COAST AS A FRONTAL BOUNDARY PUSHES INTO THE MISSISSIPPI VALLEY. THE
LOW PRESSURE TRACKS NORTHEASTWARD AS THE FRONTAL BOUNDARY MOVES INTO
THE SE U.S. AND DISSIPATES EARLY IN THE WEEK. HIGH PRESSURE BUILDS
INTO THE REGION FROM THE NORTH TUE AND CONTINUES WED.
THE EARLY PORTION OF THE FORECAST WILL BE DEPENDENT ON THE BEHAVIOR
OF THE SYSTEM AS IT CROSSES THE GULF COAST. WINDS WILL BE ROBUST...
ESPECIALLY ON THE GULF...WHERE SPEED MAY REACH CAUTION CRITERIA
THROUGH LATE SUN OR EARLY MON. ANY RESIDUAL SWELLS MAY LINGER INTO
MON AND GENERATE A RIP CURRENT THREAT. THE ATMOSPHERE WILL REMAIN
MOIST ENOUGH TO SUPPORT ISOLATED TO SCATTERED SHOWERS AND STORMS
MAINLY DURING THE DAYTIME. TEMPERATURES WILL RUN ABOVE NORMAL
ALTHOUGH A SLIGHT COOLING TREND IS EXPECTED THROUGH THE PERIOD.
&&
.MARINE...
THE FORECAST THROUGH THE UPCOMING WEEKEND WILL DEPEND HIGHLY ON
AN AREA OF LOW PRESSURE EMERGING INTO THE SOUTHERN GULF OF MEXICO
THIS MORNING...AND THE POTENTIAL FOR SOME TROPICAL DEVELOPMENT.
THE STRENGTH AND ORGANIZATION OF THIS SYSTEM WILL INFLUENCE THE
WINDS AND ANY POTENTIAL SWELL MIGRATING THROUGH THE EASTERN GULF. AS
A RESULT THE FORECAST UNCERTAINTY IS HIGHER THAN NORMAL DURING THE
FIRST SEVERAL DAYS...AND MARINERS ARE URGED TO MONITOR THE LATEST
FORECAST CLOSELY BEFORE MAKING PLANS TO BOAT ON THE GULF THROUGH THE
UPCOMING WEEKEND.
&&
.AVIATION...
VFR INTO THU MORNING WITH OCNL MID/HIGH CIG AND LIGHT EASTERLY
WINDS. CLOUDS INCREASE TO HIGH BKN-OVC DURING THE DAY WITH VCTS
FROM 03/18Z TO 04/01Z. WINDS MOSTLY SE 8-11KT.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED INTO THE EARLY
PORTION OF THE UPCOMING WEEKEND. RELATIVE HUMIDITY VALUES SHOULD
REMAIN ABOVE CRITICAL LEVELS WITH NO SIGNIFICANT FOG ISSUES IN THE
FORECAST. GENERALLY LOOKING AT EASTERLY FLOW...ALTHOUGH THE GRADIENT
MAY RELAX JUST ENOUGH THIS AFTERNOON FOR A WEAK SEA-BREEZE TO TURN
WINDS ONSHORE NEAR THE IMMEDIATE COAST...ESPECIALLY FROM AROUND
TAMPA BAY NORTHWARD ALONG THE NATURE COAST. AT THE SAME TIME...THE
BETTER CHANCES FOR AFTERNOON SHOWERS WILL EXIST ALONG THE COAST TO
THE SOUTH OF TAMPA BAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 75 89 74 / 20 20 30 20
FMY 89 74 90 75 / 60 30 50 20
GIF 90 71 89 71 / 10 10 20 10
SRQ 89 74 88 74 / 40 30 50 20
BKV 90 71 89 70 / 10 10 30 10
SPG 89 76 87 76 / 20 20 40 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
329 PM EDT Wed Oct 2 2013
.NEAR TERM [Tonight]...
The large scale longwave pattern indicated a nearly zonal flow over
Nrn stream, a weak trough over Wrn Gulf region with cutoff low over
AR/LA border, and a broad H5 ridge from Ern plains to the mid-Atlc
and stacked ridge across SE states SWD to Cuba. Deep layer low
assocd with tropical disturbance in NW Carib Sea. Local area in
between these systems allowing SSW flow above H6 to increasingly
advect moisture on east side of disturbance NWD but Nrn extent has
only reached S/Cntrl FL. At surface, main features are sfc-H7 high
over Cntrl Appalachians ridging into Cntrl Gulf region and tropical
disturbance to our south. This translates to light and dry E/NE flow
near the surface. However, RAP sounding shows that Appalachian ridge
extends down into Wrn most counties and adjacent waters. Onshore
flow around base of this ridge has set up area of higher PWATS and
instability there. This reflected in afternoon radar which indicated
that scattered showers and isolated thunderstorms continued to move
NNW across WRN Panhandle waters. Updated 18Z-00Z period to account
for higher POPs there.
During this evening into tonight, upper low will open up and lift
into Mid-South nudging Ern ridge towards Atlc. All HI RES models
show aftn precip weakening with some moving Nwd into mainly offshore
waters late. However, current convection shows little desire to die
off and believe POP over ern most waters and adjacent coast will be
higher than guidance. After coordinating with MOB, went with 30%
these areas. Dry forecast elsewhere. Expect lows from near 60 NE
tier GA counties to upper 60s SW Panhandle counties.
A High Risk for rip currents will continue into this evening for
coastal Franklin County.
&&
.SHORT TERM [Thursday Through Friday Night]...
High pressure will remain across the Carolinas through Thursday
with our region in between a drier airmass across Southern Georgia
and a more moist airmass across the Florida Panhandle. Showers are
anticipated over the coastal waters on Thursday and possibly
onshore into the Florida Panhandle, but elsewhere it should be too
dry for any precipitation.
By Friday, the pattern will begin to transition as more moisture
builds in from the south with the approaching tropical system.
Whether this ends up being an organized system or not is still
uncertain, but do expect the increasing moisture to lead to
gradually increasing rain chances, especially by Friday evening
across the Florida Panhandle and adjacent marine area.
Temperatures throughout the short term period will be near normal
values, with the exception being across South Central Georgia
where some cooler values in the lower 60s are possible.
&&
.LONG TERM [Saturday through Wednesday]...
It seems like this has been one of the more challenging and
difficult long term periods for some time. The models still
continue to have issue resolving the tropical contribution to the
weather pattern across the Southeast as well as the upper trough
moving into the plains on Friday evening and Saturday. Timing
differences abound as well as do intensity issues with the
tropical system. The GFS has obviously been on the more intense
side with this system for several runs, while the Euro has had
difficulty maintaining even a closed low for very long. While the
GFS solution may be too strong, the Euro solution also seems a bit
suspicious as it keeps the system much weaker, with the weak
surface and upper level features ultimately becoming separated
long before any interaction with the approaching upper trough.
Ultimately, a solution between the GFS and Euro, at least with
respect to development may be the eventual result. The environment
isn`t prohibitive and NHC has assigned a 70 percent chance of
development in the next 48 hours. The track of the resulting
system will likely be dependent on how quickly the system moves
northward. A slower progression of this system would likely lead
to more of an eastward track in the longer term as the approaching
upper trough would have more time to catch up with the tropical
disturbance and force it more to the northeast.
At the start of the long range period, whatever form the tropical
system is in, its moisture will be streaming northward into the
region with rain chances increasing through Saturday afternoon.
Unsettled conditions will prevail through the weekend as tropical
moisture lingers over the area. Clearing will likely be delayed
into the first of the upcoming week as the southern end of the
approaching upper trough will be slow to move out of the region.
&&
.AVIATION [Through 18z Thursday]...
We expect unlimited vis/cigs through the period. Expect E-NE
winds of 4 to 8 KT. SHRA/TSRA are too low to consider for TAFS but
if any occur it would likely be at KECP Thurs morning.
&&
.MARINE...
Easterly flow to cautionary levels offshore is expected tonight.
After a decrease in winds on Thursday, expect winds to be on the
increase out of the southeast as a tropical disturbance moves into
the Central Gulf of Mexico. Winds will likely reach advisory
criteria by Friday afternoon across the western waters and remain
high into the weekend. High winds and seas do not appear to
subside across the marine area until Sunday afternoon.
&&
.FIRE WEATHER...
Red Flag conditions are unlikely through at least this weekend.
&&
.HYDROLOGY...
River flows remain above base levels for early October with area
soils still quite moist from the summer rains. The incoming system
this weekend will need to be closely monitored. A more organized
tropical system could easily produce enough rainfall to result in
a fair amount of areal and riverine flooding into next week.
However, if the storm system is more disorganized as indicated in
some of the latest guidance, then flooding would be less of a
threat.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 65 88 69 87 67 / 0 10 10 20 30
Panama City 72 86 73 84 73 / 10 20 20 50 40
Dothan 64 88 67 88 67 / 0 10 10 10 20
Albany 61 88 63 88 64 / 0 0 10 10 20
Valdosta 61 87 64 87 65 / 0 10 10 10 20
Cross City 64 88 67 88 66 / 0 10 10 20 20
Apalachicola 73 84 74 83 73 / 10 20 20 50 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Block
SHORT TERM...Godsey
LONG TERM...Godsey
AVIATION...Block
MARINE...Godsey
FIRE WEATHER...Block
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
103 AM CDT FRI OCT 4 2013
.DISCUSSION...
854 PM CDT
FOR EVENING UPDATE...
CONVECTIVE COMPLEX NUMBER TWO AFFECTING CENTRAL AND SOUTHERN PARTS
OF THE WFO LOT CWA THIS EVENING. MCV EMBEDDED WITHIN SHORT WAVE
TROUGH INDICATED IN RADAR IMAGERY JUST EAST OF STREATOR. SEVERAL
STRONG CELLS HAVE DEVELOPED OVER THE PAST HOUR NORTH-NORTHEAST OF
THE CIRCULATION CENTER INTO NORTHEAST IL. THESE APPEAR TO BE FORMING
IN WARM ADVECTION REGION OF MCV CIRCULATION...IN A REGION OF
SLIGHTLY STRONGER EFFECTIVE DEEP BULK SHEAR THAN ARE THE NORTH-SOUTH
ORIENTED LINE OF STORMS FARTHER SOUTH. DESPITE SOME COOLING OF THE
NOCTURNAL BOUNDARY LAYER...CONTINUE TO SEE SOME VELOCITY SIGNATURES
ASSOCIATED WITH WET MICROBURSTS...WITH REPORTS OF 40-45 MPH WIND
RECENTLY NEAR PLAINFIELD. WOULD EXPECT THESE STORMS TO CONTINUE TO
PUSH EAST-NORTHEAST ACROSS AREAS EAST OF THE FOX RIVER/I-55 THROUGH
ABOUT 10-11 PM CDT. STRONGER CELLS MAY PRODUCE BRIEF 40-50 MPH GUSTS
AND PERHAPS SOME PENNY-QUARTER SIZE HAIL...IN ADDITION TO BRIEF
HEAVY RAINFALL.
ATTENTION THEN TURNS TO THE WEST OVER IA...WHERE ADDITIONAL
THUNDERSTORMS WERE DEVELOPING AHEAD OF ANOTHER SHORT WAVE TROUGH
OVER EASTERN NEBRASKA/WESTERN IOWA. GUIDANCE DEPICTS THIS ACTIVITY
SHOULD SPREAD NORTHEAST AS SOUTHWEST LOW LEVEL JET INCREASES
OVERNIGHT...SPREADING INTO NORTHWESTERN PORTIONS OF THE CWA PRE-DAWN
FRIDAY MORNING. RECENT HRRR HIGH-RES CONVECTION ALLOWING SOLUTION
BREAKS OUT ADDITIONAL CONVECTION AFTER MIDNIGHT ACROSS WESTERN
CWA...THOUGH THE STRONGEST MOISTURE TRANSPORT APPEARS TO FOCUS
ACROSS THE NORTHWEST.
HAVE ADJUSTED POP GRIDS TO ADD DETAIL WITH CURRENT ACTIVITY ACROSS
THE CENTRAL/EASTERN PARTS OF THE CWA...AND HAVE BOOSTED POPS A BIT
NORTHWEST DURING THE LATE NIGHT HOURS.
RATZER
//PREV DISCUSSION...
303 PM CDT
SYNOPSIS...UNSETTLED WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT
A DRY WARMING TREND IS EXPECTED NEXT WEEK.
REST OF DAY AND TONIGHT...
A LOW PRESSURE TROUGH EXTENDS FROM THE PLAINS INTO SW WI WITH A
STATIONARY/WARM FRONT OVER SOUTHERN WI. A SHORTWAVE TROUGH IS ALSO
OVER MN/WI AND THE SHORTWAVE WILL PASS OVER IL LATER THIS AFTN. THE
STRONGEST PART OF THE SHORTWAVE AND SUBSEQUENT FORCING WILL STAY
NORTH OF THE CWA AND PASS OVER CENTRAL/SOUTHERN WI. EXPECTING THE
MAJORITY OF PRECIP TO STAY OVER WI CLOSER TO THE FORCING. HOWEVER
GIVEN RECENT RADAR TRENDS...THINKING THE NAM MAY BE ON TO SOMETHING
WITH MEASURABLE PRECIP ACROSS THE CWA LATE THIS AFTN THROUGH THIS
EVENING.
THE HRRR WOULD ALSO SUPPORT THIS THEORY AS WELL...THEREFORE PUT A
LINE OF SHRA/TSRA MOVING THROUGH NORTHERN IL AND INDIANA IN THE
GRIDS. OVERTIME HAVE THE SOUTHERN EXTENT OF THE LINE...SOUTH OF
I-80...WEAKENING. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT NORTH OVERNIGHT WITH THE WARM FRONT.
FOR SVR POTENTIAL...THINKING A COUPLE OF STORMS MAY PULSE UP TO
STRONG OR SVR...BUT OVERALL JUST EXPECTING GENERAL THUNDERSTORMS.
MOISTURE IS PLENTIFUL WITH DEWPOINTS AROUND 70 AND PWAT VALUES
AROUND 1.5 INCHES...2 STANDARD DEVIATIONS ABOVE NORMAL FOR OCTOBER.
SFC CAPE VALUES ARE 1000-2500 J/KG WITH 30 KT OF SHEAR. FORECAST
SOUNDINGS FEATURE SKINNY CAPE SO NOT EXPECTING LARGE HAIL...BUT A
WIND THREAT IS CERTAINLY POSSIBLE. SOME OF THE CELLS HAVE ALREADY
FEATURE BOW-ESQ CHARACTERISTICS. THEREFORE THINKING THE MAIN
THREATS WILL BE HEAVY RAIN AND GUSTY WINDS.
KEPT TEMPS A BIT WARMER TONIGHT AS THICK STRATUS SHOULD BE
PLENTIFUL. LOOKING AT LOW TEMPS IN THE MID 60S. WITH DEWPOINTS IN
THE MID 60S AS WELL...EXPECTING AREAS OF FOG AND POSSIBLE DENSE FOG
AGAIN AFTER MIDNIGHT THROUGH EARLY FRIDAY MORNING.
FRIDAY AND SATURDAY...
A STRONG SURFACE LOW EJECTS OUT OF THE ROCKIES TOMORROW AND PASSES
TO OUR NW THROUGH WI SATURDAY NIGHT. GUIDANCE STILL DIFFERS ON HOW
FAST THE LOW WILL PASS THROUGH THE REGION...BUT IN GENERAL EXPECTING
THE COLD FRONT TO IMPACT THE CWA SATURDAY AND SATURDAY NIGHT.
FOR FRIDAY...EXPECTING A PRIMARILY DRY DAY BUT COULD SEE A FEW
SHOWERS AND/OR STORMS ALONG THE IL/WI BORDER AS THE WARM FRONT
SHIFTS NORTH. ANOTHER HOT AND MUGGY DAY WITH HIGHS IN THE MID TO
UPPER 80S AND DEWPOINTS IN THE MID 60S. THERE IS A CONCERN SIMILAR
TO TODAY THAT IF THE STRATUS LINGERS TOO LONG...TEMPS COULD BE
COOLER THAN FORECAST. HOWEVER THE FRONT WILL START OUT FARTHER NORTH
TOMORROW AND THERE WILL BE BETTER MIXING...SO THINKING THE STRATUS
WILL BURN OFF FASTER THAN THIS MORNING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FORECAST CAPE VALUES OF
1000-1500 J/KG AND PWAT VALUES 1.5-1.75 INCHES. 0-6 KM SHEAR LOOKS
FAVORABLE FOR SEVERE WEATHER WITH VALUES OF 35-40 KT AHEAD OF THE
FRONT AND 50-70 KT ALONG THE FRONT. TIMING IS ALSO FAVORABLE AS
INSTABILITY CAN GROW ACROSS THE REGION BEFORE THE FRONT SLIDES
ACROSS. EXPECTING THE STRONGER STORMS AND PRECIP TO FALL ONCE AGAIN
OVER WI AS THE UPPER LEVEL JETS LEFT EXIT REGION WILL PROVIDE
ADDITIONAL LIFT.
EXTENDED...SUNDAY THROUGH WEDNESDAY...
THE UPPER LEVEL LOW PASSES OVER THE REGION LATE THIS WEEKEND AS THE
SURFACE LOW LIFTS NORTHEAST INTO QUEBEC. UPPER LEVEL RIDGING AND A
SURFACE HIGH MOVE OVER THE CWA BEFORE CONTINUING EAST AND REACHING
THE ATLANTIC COAST BY MID WEEK.
THE SURFACE LOW WILL PASS OVER NORTHERN LAKE MI SUNDAY WITH WRAP
AROUND SHOWERS POSSIBLE SUNDAY NIGHT/MONDAY MORNING. GUIDANCE DOES
DIFFER ON HOW QUICKLY THE LOW SHIFTS TO THE NE...AND THE SOUTHERN
EXTENT OF THE WRAP AROUND SHOWERS WILL DEPEND ON THE TRACK OF THE
LOW.
THE END OF THE WEEKEND WILL BE COOL BUT A GRADUAL WARM UP TO ABOVE
NORMAL TEMPS IS EXPECTED THROUGH MID NEXT WEEK AS THE HIGH BUILDS IN.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PSBL VCTS ARRIVING AFT 07Z THRU 09Z.
* PATCHY MVFR CIGS DEVELOPING THRU DAYBREAK.
* SOUTHWEST WINDS BACKING SOUTHEAST THIS AFTN...SPEEDS INCREASING
TO ARND 10KT AND OCCASIONAL GUSTS TO 18KT THIS AFTN.
BEACHLER
//DISCUSSION...UPDATED 06Z...
IR IMAGERY EARLY THIS MORNING SHOWS A COMPLEX OF
SHOWERS/THUNDERSTORMS DEVELOPING OVER CENTRAL/WESTERN IOWA...WITH
A WARM FRONTAL BOUNDARY EXTENDING EAST THROUGH SOUTHERN WISCONSIN.
IT IS LIKELY THAT THIS COMPLEX OF THUNDERSTORMS WILL CONTINUE TO
SLIDE EAST/NORTHEAST ALONG THIS BOUNDARY. A FEW ISOLATED
THUNDERSTORMS HAVE DEVELOPED OVER NORTHWEST IL...AND MAY ARRIVE
NEAR RFD/DPA/ORD/MDW BTWN 07-11Z...THEN SHOULD LIFT NORTHEAST OF
TAF SITES. THERE IS ALSO SOME INDICATION THAT PATCHY MVFR CIGS MAY
DEVELOP...AND EVEN ISOLATED AREAS OF IFR CIGS. ALTHOUGH FEEL THAT
WITH THE SOUTHERLY FLOW CURRENTLY GOING ON AND JUST ENOUGH WIND TO
KEEP THINGS MIXING AT THE SFC...THAT IF CIGS AND VSBYS DO REDUCE
THEY SHOULD NOT BE TOO LOW. SO HAVE BROUGHT CIGS UP
SLIGHTLY...WHICH SEEMS TO MATCH UP WITH WHAT IS GOING ON TO THE
WEST/SOUTHWEST OF THE REGION.
GUIDANCE HAS BEEN INDICATING THAT AS THE COMPLEX OF THUNDERSTORMS
SLIDES NORTHEAST THAT IT MAY HELP PUSH THE FRONTAL BOUNDARY BACK
SOUTH ACROSS NORTHERN IL/NORTHWEST IN AIRFIELDS MIDDAY/EARLY AFTN.
IF THIS OCCURS WINDS WILL BACK FURTHER TO THE SOUTHEAST AND
POSSIBLY TO THE EAST ACROSS FAR NORTHEAST IL. THE GRADIENT DOES
INCREASE MIDDAY AND HAVE HELD ONTO MENTION OF OCCASIONAL GUSTS
INTO THE MID TEENS. AT THIS TIME IT DOES APPEAR THE BULK OF TODAY
WILL REMAIN VFR WITH A DRY FORECAST...HOWEVER AN ISOLATED
SHOWER/THUNDERSTORM CANNOT BE RULED OUT BY LATE THIS AFTN/EVENING.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN VCTS TIMING AND COVERAGE.
* MEDIUM CONFIDENCE IN CIGS/VSBY FORECAST IN CURRENT TAF.
* MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST.
* MEDIUM/HIGH CONFIDENCE IN TSRA THIS AFT HOLDING OFF UNTIL AFT
21Z.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...TSRA LIKELY.
SUNDAY...CHC OF SHRA.
MONDAY-WEDNESDAY...VFR.
DZ
&&
.MARINE...
324 PM CDT
LOW PRESSURE SITTING ON THE MN-IA BORDER AT MID AFTERNOON WILL
MOVE ENE ALONG A STATIONARY FRONT DRAPED ACROSS CENTRAL LAKE MI
TONIGHT...WITH THE LOW REACHING CENTRAL LOWER MI BY DAWN. STRONG
LOW PRESSURE WILL REMAIN IN THE CENTRAL HIGH PLAINS TONIGHT AND
THEN MOVE NE FRI...REACHING SOUTHERN MN BY SAT MORNING. AS THIS
LOW CONTINUES NE TO THE WESTERN U.P. OF MI SAT...AND THEN ACROSS
LAKE SUPERIOR INTO ONTARIO SAT NIGHT IT WILL SWEEP A STRONG COLD
FRONT ACROSS THE UPPER MIDWEST AND INTO THE UPPER GREAT LAKES.
THIS LOW MOVES FURTHER OFF TO THE NE TOWARD SOUTHERN HUDSON BAY
SUN AND SUN NIGHT.
A STRONG S TO SW FLOW WILL PRECEDE THE PLAINS LOW AND ITS COLD
FRONT...BUT DUE TO THE VERY WARM AIR IT WILL CONTINUE TO SPREAD
ACROSS THE REGION IT WILL BE QUITE STABLE AT AND CLOSE TO THE
SURFACE OF THE LAKE WHICH WILL PREVENT THE STRONGER WINDS FROM
PENETRATING DOW TO NEAR THE LAKE SURFACE. HOWEVER...ONCE THE COLD
FRONT PASSES W TO E ACROSS THE LAKE DURING LATER SAT AND SAT
EVENING MUCH COOLER AIR WILL QUICKLY BE SWEPT ACROSS THE REGION.
WITH THE STILL RELATIVELY WARM LAKE WATER AND THE LOW LEVEL COLD
AIR ADVECTION BEHIND THE FRONT IT WILL TURN FROM A STABLE TO A
VERY UNSTABLE CONDITION AT THE LAKE SURFACE...WHICH WILL ALLOW
STRONG SW TO W WINDS BEHIND THE COLD FRONT AND IN THE WAKE OF THE
DEPARTING LOW TO EFFICIENTLY MIX ALL THE WAY DOWN TO THE LAKE
SURFACE. WHILE THERE MAY BE A LOW END GALE FORCE GUST OR TWO
OBSERVED SATURDAY NIGHT AFTER THE COLD FRONTAL PASSAGE...BASED ON
CURRENT MODEL GUIDANCE AN UPPER LIMIT OF 30KT SUSTAINED WINDS
APPEARS TO BE THE APPROPRIATE FORECAST.
MODELS GENERALLY AGREE IN MOVING THE LOW QUICKLY TO THE NE AND
NNE ACROSS ONTARIO TO NEAR SOUTHERN HUDSON BAY BY SUNDAY
NIGHT...THE GRADIENT ACROSS LAKE MI WILL BE RELAXING DURING THE
DAY SUN...WITH A CORRESPONDING GRADUAL DECREASE IN WIND SPEEDS
OCCURRING AS THE DAY PROGRESSES.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1004 PM CDT THU OCT 3 2013
.DISCUSSION...
854 PM CDT
FOR EVENING UPDATE...
CONVECTIVE COMPLEX NUMBER TWO AFFECTING CENTRAL AND SOUTHERN PARTS
OF THE WFO LOT CWA THIS EVENING. MCV EMBEDDED WITHIN SHORT WAVE
TROUGH INDICATED IN RADAR IMAGERY JUST EAST OF STREATOR. SEVERAL
STRONG CELLS HAVE DEVELOPED OVER THE PAST HOUR NORTH-NORTHEAST OF
THE CIRCULATION CENTER INTO NORTHEAST IL. THESE APPEAR TO BE FORMING
IN WARM ADVECTION REGION OF MCV CIRCULATION...IN A REGION OF
SLIGHTLY STRONGER EFFECTIVE DEEP BULK SHEAR THAN ARE THE NORTH-SOUTH
ORIENTED LINE OF STORMS FARTHER SOUTH. DESPITE SOME COOLING OF THE
NOCTURNAL BOUNDARY LAYER...CONTINUE TO SEE SOME VELOCITY SIGNATURES
ASSOCIATED WITH WET MICROBURSTS...WITH REPORTS OF 40-45 MPH WIND
RECENTLY NEAR PLAINFIELD. WOULD EXPECT THESE STORMS TO CONTINUE TO
PUSH EAST-NORTHEAST ACROSS AREAS EAST OF THE FOX RIVER/I-55 THROUGH
ABOUT 10-11 PM CDT. STRONGER CELLS MAY PRODUCE BRIEF 40-50 MPH GUSTS
AND PERHAPS SOME PENNY-QUARTER SIZE HAIL...IN ADDITION TO BRIEF
HEAVY RAINFALL.
ATTENTION THEN TURNS TO THE WEST OVER IA...WHERE ADDITIONAL
THUNDERSTORMS WERE DEVELOPING AHEAD OF ANOTHER SHORT WAVE TROUGH
OVER EASTERN NEBRASKA/WESTERN IOWA. GUIDANCE DEPICTS THIS ACTIVITY
SHOULD SPREAD NORTHEAST AS SOUTHWEST LOW LEVEL JET INCREASES
OVERNIGHT...SPREADING INTO NORTHWESTERN PORTIONS OF THE CWA PRE-DAWN
FRIDAY MORNING. RECENT HRRR HIGH-RES CONVECTION ALLOWING SOLUTION
BREAKS OUT ADDITIONAL CONVECTION AFTER MIDNIGHT ACROSS WESTERN
CWA...THOUGH THE STRONGEST MOISTURE TRANSPORT APPEARS TO FOCUS
ACROSS THE NORTHWEST.
HAVE ADJUSTED POP GRIDS TO ADD DETAIL WITH CURRENT ACTIVITY ACROSS
THE CENTRAL/EASTERN PARTS OF THE CWA...AND HAVE BOOSTED POPS A BIT
NORTHWEST DURING THE LATE NIGHT HOURS.
RATZER
//PREV DISCUSSION...
303 PM CDT
SYNOPSIS...UNSETTLED WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT
A DRY WARMING TREND IS EXPECTED NEXT WEEK.
REST OF DAY AND TONIGHT...
A LOW PRESSURE TROUGH EXTENDS FROM THE PLAINS INTO SW WI WITH A
STATIONARY/WARM FRONT OVER SOUTHERN WI. A SHORTWAVE TROUGH IS ALSO
OVER MN/WI AND THE SHORTWAVE WILL PASS OVER IL LATER THIS AFTN. THE
STRONGEST PART OF THE SHORTWAVE AND SUBSEQUENT FORCING WILL STAY
NORTH OF THE CWA AND PASS OVER CENTRAL/SOUTHERN WI. EXPECTING THE
MAJORITY OF PRECIP TO STAY OVER WI CLOSER TO THE FORCING. HOWEVER
GIVEN RECENT RADAR TRENDS...THINKING THE NAM MAY BE ON TO SOMETHING
WITH MEASURABLE PRECIP ACROSS THE CWA LATE THIS AFTN THROUGH THIS
EVENING.
THE HRRR WOULD ALSO SUPPORT THIS THEORY AS WELL...THEREFORE PUT A
LINE OF SHRA/TSRA MOVING THROUGH NORTHERN IL AND INDIANA IN THE
GRIDS. OVERTIME HAVE THE SOUTHERN EXTENT OF THE LINE...SOUTH OF
I-80...WEAKENING. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT NORTH OVERNIGHT WITH THE WARM FRONT.
FOR SVR POTENTIAL...THINKING A COUPLE OF STORMS MAY PULSE UP TO
STRONG OR SVR...BUT OVERALL JUST EXPECTING GENERAL THUNDERSTORMS.
MOISTURE IS PLENTIFUL WITH DEWPOINTS AROUND 70 AND PWAT VALUES
AROUND 1.5 INCHES...2 STANDARD DEVIATIONS ABOVE NORMAL FOR OCTOBER.
SFC CAPE VALUES ARE 1000-2500 J/KG WITH 30 KT OF SHEAR. FORECAST
SOUNDINGS FEATURE SKINNY CAPE SO NOT EXPECTING LARGE HAIL...BUT A
WIND THREAT IS CERTAINLY POSSIBLE. SOME OF THE CELLS HAVE ALREADY
FEATURE BOW-ESQ CHARACTERISTICS. THEREFORE THINKING THE MAIN
THREATS WILL BE HEAVY RAIN AND GUSTY WINDS.
KEPT TEMPS A BIT WARMER TONIGHT AS THICK STRATUS SHOULD BE
PLENTIFUL. LOOKING AT LOW TEMPS IN THE MID 60S. WITH DEWPOINTS IN
THE MID 60S AS WELL...EXPECTING AREAS OF FOG AND POSSIBLE DENSE FOG
AGAIN AFTER MIDNIGHT THROUGH EARLY FRIDAY MORNING.
FRIDAY AND SATURDAY...
A STRONG SURFACE LOW EJECTS OUT OF THE ROCKIES TOMORROW AND PASSES
TO OUR NW THROUGH WI SATURDAY NIGHT. GUIDANCE STILL DIFFERS ON HOW
FAST THE LOW WILL PASS THROUGH THE REGION...BUT IN GENERAL EXPECTING
THE COLD FRONT TO IMPACT THE CWA SATURDAY AND SATURDAY NIGHT.
FOR FRIDAY...EXPECTING A PRIMARILY DRY DAY BUT COULD SEE A FEW
SHOWERS AND/OR STORMS ALONG THE IL/WI BORDER AS THE WARM FRONT
SHIFTS NORTH. ANOTHER HOT AND MUGGY DAY WITH HIGHS IN THE MID TO
UPPER 80S AND DEWPOINTS IN THE MID 60S. THERE IS A CONCERN SIMILAR
TO TODAY THAT IF THE STRATUS LINGERS TOO LONG...TEMPS COULD BE
COOLER THAN FORECAST. HOWEVER THE FRONT WILL START OUT FARTHER NORTH
TOMORROW AND THERE WILL BE BETTER MIXING...SO THINKING THE STRATUS
WILL BURN OFF FASTER THAN THIS MORNING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FORECAST CAPE VALUES OF
1000-1500 J/KG AND PWAT VALUES 1.5-1.75 INCHES. 0-6 KM SHEAR LOOKS
FAVORABLE FOR SEVERE WEATHER WITH VALUES OF 35-40 KT AHEAD OF THE
FRONT AND 50-70 KT ALONG THE FRONT. TIMING IS ALSO FAVORABLE AS
INSTABILITY CAN GROW ACROSS THE REGION BEFORE THE FRONT SLIDES
ACROSS. EXPECTING THE STRONGER STORMS AND PRECIP TO FALL ONCE AGAIN
OVER WI AS THE UPPER LEVEL JETS LEFT EXIT REGION WILL PROVIDE
ADDITIONAL LIFT.
EXTENDED...SUNDAY THROUGH WEDNESDAY...
THE UPPER LEVEL LOW PASSES OVER THE REGION LATE THIS WEEKEND AS THE
SURFACE LOW LIFTS NORTHEAST INTO QUEBEC. UPPER LEVEL RIDGING AND A
SURFACE HIGH MOVE OVER THE CWA BEFORE CONTINUING EAST AND REACHING
THE ATLANTIC COAST BY MID WEEK.
THE SURFACE LOW WILL PASS OVER NORTHERN LAKE MI SUNDAY WITH WRAP
AROUND SHOWERS POSSIBLE SUNDAY NIGHT/MONDAY MORNING. GUIDANCE DOES
DIFFER ON HOW QUICKLY THE LOW SHIFTS TO THE NE...AND THE SOUTHERN
EXTENT OF THE WRAP AROUND SHOWERS WILL DEPEND ON THE TRACK OF THE
LOW.
THE END OF THE WEEKEND WILL BE COOL BUT A GRADUAL WARM UP TO ABOVE
NORMAL TEMPS IS EXPECTED THROUGH MID NEXT WEEK AS THE HIGH BUILDS IN.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* SHRA/TSRA TONIGHT.
* POSSIBILITY OF IFR CEILINGS DEVELOPING AGAIN TONIGHT INTO
FRIDAY MORNING.
* FOG WITH MVFR-IFR VIS TONIGHT/EARLY FRIDAY MORNING.
DZ
//DISCUSSION...UPDATED 00Z...
RADAR INDICATES SHRA/TSRA WEAKENING ACROSS PORTIONS OF NORTHERN
ILLINOIS THIS EVENING AND TREND IS EXPECTED TO CONTINUE. WARM VERY
MOIST AIRMASS TO STAY IN PLACE THROUGH FRIDAY NIGHT. SERIES OF
UPPER LEVEL DISTURBANCES MOVING TO THE NORTHEAST MAY PROVIDE A FOCUS
FOR ADDITIONAL SHRA/TSRA DEVELOPMENT...HOWEVER...HIGHER COVERAGE
SHRA/TSRA EXPECTED CLOSER TO FRONTAL BOUNDARIES OVER WI AND IA.
SOUTH WINDS HAVE DIMINISHED AND WILL REMAIN LIGHT THROUGH EARLY
FRIDAY MORNING. SIMILAR TO LAST NIGHT..LOW CEILINGS AND FOG ARE
EXPECTED TO REDEVELOP OVERNIGHT AND AGAIN FRIDAY NIGHT.
DZ
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE WITH CEILINGS...MEDIUM TO LOW CONFIDENCE WITH
POTENTIAL FOR LIFR CEILINGS TONIGHT/EARLY FRIDAY MORNING.
* HIGH CONFIDENCE IN WIND DIRECTION AND SPEED.
* HIGH CONFIDENCE FOR FOG/MVFR VIS TONIGHT EARLY FRIDAY
MORNING...LOW CONFIDENCE WITH POTENTIAL FOR LIFR VIS.
DZ
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...TSRA LIKELY.
SUNDAY...CHC OF SHRA.
MONDAY-WEDNESDAY...VFR.
DZ
&&
.MARINE...
324 PM CDT
LOW PRESSURE SITTING ON THE MN-IA BORDER AT MID AFTERNOON WILL
MOVE ENE ALONG A STATIONARY FRONT DRAPED ACROSS CENTRAL LAKE MI
TONIGHT...WITH THE LOW REACHING CENTRAL LOWER MI BY DAWN. STRONG
LOW PRESSURE WILL REMAIN IN THE CENTRAL HIGH PLAINS TONIGHT AND
THEN MOVE NE FRI...REACHING SOUTHERN MN BY SAT MORNING. AS THIS
LOW CONTINUES NE TO THE WESTERN U.P. OF MI SAT...AND THEN ACROSS
LAKE SUPERIOR INTO ONTARIO SAT NIGHT IT WILL SWEEP A STRONG COLD
FRONT ACROSS THE UPPER MIDWEST AND INTO THE UPPER GREAT LAKES.
THIS LOW MOVES FURTHER OFF TO THE NE TOWARD SOUTHERN HUDSON BAY
SUN AND SUN NIGHT.
A STRONG S TO SW FLOW WILL PRECEDE THE PLAINS LOW AND ITS COLD
FRONT...BUT DUE TO THE VERY WARM AIR IT WILL CONTINUE TO SPREAD
ACROSS THE REGION IT WILL BE QUITE STABLE AT AND CLOSE TO THE
SURFACE OF THE LAKE WHICH WILL PREVENT THE STRONGER WINDS FROM
PENETRATING DOW TO NEAR THE LAKE SURFACE. HOWEVER...ONCE THE COLD
FRONT PASSES W TO E ACROSS THE LAKE DURING LATER SAT AND SAT
EVENING MUCH COOLER AIR WILL QUICKLY BE SWEPT ACROSS THE REGION.
WITH THE STILL RELATIVELY WARM LAKE WATER AND THE LOW LEVEL COLD
AIR ADVECTION BEHIND THE FRONT IT WILL TURN FROM A STABLE TO A
VERY UNSTABLE CONDITION AT THE LAKE SURFACE...WHICH WILL ALLOW
STRONG SW TO W WINDS BEHIND THE COLD FRONT AND IN THE WAKE OF THE
DEPARTING LOW TO EFFICIENTLY MIX ALL THE WAY DOWN TO THE LAKE
SURFACE. WHILE THERE MAY BE A LOW END GALE FORCE GUST OR TWO
OBSERVED SATURDAY NIGHT AFTER THE COLD FRONTAL PASSAGE...BASED ON
CURRENT MODEL GUIDANCE AN UPPER LIMIT OF 30KT SUSTAINED WINDS
APPEARS TO BE THE APPROPRIATE FORECAST.
MODELS GENERALLY AGREE IN MOVING THE LOW QUICKLY TO THE NE AND
NNE ACROSS ONTARIO TO NEAR SOUTHERN HUDSON BAY BY SUNDAY
NIGHT...THE GRADIENT ACROSS LAKE MI WILL BE RELAXING DURING THE
DAY SUN...WITH A CORRESPONDING GRADUAL DECREASE IN WIND SPEEDS
OCCURRING AS THE DAY PROGRESSES.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
854 PM CDT THU OCT 3 2013
.DISCUSSION...
854 PM CDT
FOR EVENING UPDATE...
CONVECTIVE COMPLEX NUMBER TWO AFFECTING CENTRAL AND SOUTHERN PARTS
OF THE WFO LOT CWA THIS EVENING. MCV EMBEDDED WITHIN SHORT WAVE
TROUGH INDICATED IN RADAR IMAGERY JUST EAST OF STREATOR. SEVERAL
STRONG CELLS HAVE DEVELOPED OVER THE PAST HOUR NORTH-NORTHEAST OF
THE CIRCULATION CENTER INTO NORTHEAST IL. THESE APPEAR TO BE FORMING
IN WARM ADVECTION REGION OF MCV CIRCULATION...IN A REGION OF
SLIGHTLY STRONGER EFFECTIVE DEEP BULK SHEAR THAN ARE THE NORTH-SOUTH
ORIENTED LINE OF STORMS FARTHER SOUTH. DESPITE SOME COOLING OF THE
NOCTURNAL BOUNDARY LAYER...CONTINUE TO SEE SOME VELOCITY SIGNATURES
ASSOCIATED WITH WET MICROBURSTS...WITH REPORTS OF 40-45 MPH WIND
RECENTLY NEAR PLAINFIELD. WOULD EXPECT THESE STORMS TO CONTINUE TO
PUSH EAST-NORTHEAST ACROSS AREAS EAST OF THE FOX RIVER/I-55 THROUGH
ABOUT 10-11 PM CDT. STRONGER CELLS MAY PRODUCE BRIEF 40-50 MPH GUSTS
AND PERHAPS SOME PENNY-QUARTER SIZE HAIL...IN ADDITION TO BRIEF
HEAVY RAINFALL.
ATTENTION THEN TURNS TO THE WEST OVER IA...WHERE ADDITIONAL
THUNDERSTORMS WERE DEVELOPING AHEAD OF ANOTHER SHORT WAVE TROUGH
OVER EASTERN NEBRASKA/WESTERN IOWA. GUIDANCE DEPICTS THIS ACTIVITY
SHOULD SPREAD NORTHEAST AS SOUTHWEST LOW LEVEL JET INCREASES
OVERNIGHT...SPREADING INTO NORTHWESTERN PORTIONS OF THE CWA PRE-DAWN
FRIDAY MORNING. RECENT HRRR HIGH-RES CONVECTION ALLOWING SOLUTION
BREAKS OUT ADDITIONAL CONVECTION AFTER MIDNIGHT ACROSS WESTERN
CWA...THOUGH THE STRONGEST MOISTURE TRANSPORT APPEARS TO FOCUS
ACROSS THE NORTHWEST.
HAVE ADJUSTED POP GRIDS TO ADD DETAIL WITH CURRENT ACTIVITY ACROSS
THE CENTRAL/EASTERN PARTS OF THE CWA...AND HAVE BOOSTED POPS A BIT
NORTHWEST DURING THE LATE NIGHT HOURS.
RATZER
&&
.PREV DISCUSSION...
303 PM CDT
SYNOPSIS...UNSETTLED WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT
A DRY WARMING TREND IS EXPECTED NEXT WEEK.
REST OF DAY AND TONIGHT...
A LOW PRESSURE TROUGH EXTENDS FROM THE PLAINS INTO SW WI WITH A
STATIONARY/WARM FRONT OVER SOUTHERN WI. A SHORTWAVE TROUGH IS ALSO
OVER MN/WI AND THE SHORTWAVE WILL PASS OVER IL LATER THIS AFTN. THE
STRONGEST PART OF THE SHORTWAVE AND SUBSEQUENT FORCING WILL STAY
NORTH OF THE CWA AND PASS OVER CENTRAL/SOUTHERN WI. EXPECTING THE
MAJORITY OF PRECIP TO STAY OVER WI CLOSER TO THE FORCING. HOWEVER
GIVEN RECENT RADAR TRENDS...THINKING THE NAM MAY BE ON TO SOMETHING
WITH MEASURABLE PRECIP ACROSS THE CWA LATE THIS AFTN THROUGH THIS
EVENING.
THE HRRR WOULD ALSO SUPPORT THIS THEORY AS WELL...THEREFORE PUT A
LINE OF SHRA/TSRA MOVING THROUGH NORTHERN IL AND INDIANA IN THE
GRIDS. OVERTIME HAVE THE SOUTHERN EXTENT OF THE LINE...SOUTH OF
I-80...WEAKENING. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT NORTH OVERNIGHT WITH THE WARM FRONT.
FOR SVR POTENTIAL...THINKING A COUPLE OF STORMS MAY PULSE UP TO
STRONG OR SVR...BUT OVERALL JUST EXPECTING GENERAL THUNDERSTORMS.
MOISTURE IS PLENTIFUL WITH DEWPOINTS AROUND 70 AND PWAT VALUES
AROUND 1.5 INCHES...2 STANDARD DEVIATIONS ABOVE NORMAL FOR OCTOBER.
SFC CAPE VALUES ARE 1000-2500 J/KG WITH 30 KT OF SHEAR. FORECAST
SOUNDINGS FEATURE SKINNY CAPE SO NOT EXPECTING LARGE HAIL...BUT A
WIND THREAT IS CERTAINLY POSSIBLE. SOME OF THE CELLS HAVE ALREADY
FEATURE BOW-ESQ CHARACTERISTICS. THEREFORE THINKING THE MAIN
THREATS WILL BE HEAVY RAIN AND GUSTY WINDS.
KEPT TEMPS A BIT WARMER TONIGHT AS THICK STRATUS SHOULD BE
PLENTIFUL. LOOKING AT LOW TEMPS IN THE MID 60S. WITH DEWPOINTS IN
THE MID 60S AS WELL...EXPECTING AREAS OF FOG AND POSSIBLE DENSE FOG
AGAIN AFTER MIDNIGHT THROUGH EARLY FRIDAY MORNING.
FRIDAY AND SATURDAY...
A STRONG SURFACE LOW EJECTS OUT OF THE ROCKIES TOMORROW AND PASSES
TO OUR NW THROUGH WI SATURDAY NIGHT. GUIDANCE STILL DIFFERS ON HOW
FAST THE LOW WILL PASS THROUGH THE REGION...BUT IN GENERAL EXPECTING
THE COLD FRONT TO IMPACT THE CWA SATURDAY AND SATURDAY NIGHT.
FOR FRIDAY...EXPECTING A PRIMARILY DRY DAY BUT COULD SEE A FEW
SHOWERS AND/OR STORMS ALONG THE IL/WI BORDER AS THE WARM FRONT
SHIFTS NORTH. ANOTHER HOT AND MUGGY DAY WITH HIGHS IN THE MID TO
UPPER 80S AND DEWPOINTS IN THE MID 60S. THERE IS A CONCERN SIMILAR
TO TODAY THAT IF THE STRATUS LINGERS TOO LONG...TEMPS COULD BE
COOLER THAN FORECAST. HOWEVER THE FRONT WILL START OUT FARTHER NORTH
TOMORROW AND THERE WILL BE BETTER MIXING...SO THINKING THE STRATUS
WILL BURN OFF FASTER THAN THIS MORNING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FORECAST CAPE VALUES OF
1000-1500 J/KG AND PWAT VALUES 1.5-1.75 INCHES. 0-6 KM SHEAR LOOKS
FAVORABLE FOR SEVERE WEATHER WITH VALUES OF 35-40 KT AHEAD OF THE
FRONT AND 50-70 KT ALONG THE FRONT. TIMING IS ALSO FAVORABLE AS
INSTABILITY CAN GROW ACROSS THE REGION BEFORE THE FRONT SLIDES
ACROSS. EXPECTING THE STRONGER STORMS AND PRECIP TO FALL ONCE AGAIN
OVER WI AS THE UPPER LEVEL JETS LEFT EXIT REGION WILL PROVIDE
ADDITIONAL LIFT.
EXTENDED...SUNDAY THROUGH WEDNESDAY...
THE UPPER LEVEL LOW PASSES OVER THE REGION LATE THIS WEEKEND AS THE
SURFACE LOW LIFTS NORTHEAST INTO QUEBEC. UPPER LEVEL RIDGING AND A
SURFACE HIGH MOVE OVER THE CWA BEFORE CONTINUING EAST AND REACHING
THE ATLANTIC COAST BY MID WEEK.
THE SURFACE LOW WILL PASS OVER NORTHERN LAKE MI SUNDAY WITH WRAP
AROUND SHOWERS POSSIBLE SUNDAY NIGHT/MONDAY MORNING. GUIDANCE DOES
DIFFER ON HOW QUICKLY THE LOW SHIFTS TO THE NE...AND THE SOUTHERN
EXTENT OF THE WRAP AROUND SHOWERS WILL DEPEND ON THE TRACK OF THE
LOW.
THE END OF THE WEEKEND WILL BE COOL BUT A GRADUAL WARM UP TO ABOVE
NORMAL TEMPS IS EXPECTED THROUGH MID NEXT WEEK AS THE HIGH BUILDS IN.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* SHRA/TSRA TONIGHT.
* POSSIBILITY OF LOW END MVFR OR IFR CEILINGS DEVELOPING ONCE
AGAIN TONIGHT INTO FRIDAY MORNING.
* FOG WITH MVFR-IFR VIS TONIGHT/EARLY FRIDAY MORNING.
DZ
//DISCUSSION...UPDATED 00Z...
RADAR INDICATES SHRA/TSRA WEAKENING ACROSS PORTIONS OF NORTHERN
ILLINOIS THIS EVENING AND TREND IS EXPECTED TO CONTINUE. WARM VERY
MOIST AIRMASS TO STAY IN PLACE THROUGH FRIDAY NIGHT. SERIES OF
UPPER LEVEL DISTURBANCES MOVING TO THE NORTHEAST MAY PROVIDE A FOCUS
FOR ADDITIONAL SHRA/TSRA DEVELOPMENT...HOWEVER...HIGHER COVERAGE
SHRA/TSRA EXPECTED CLOSER TO FRONTAL BOUNDARIES OVER WI AND IA.
SOUTH WINDS HAVE DIMINISHED AND WILL REMAIN LIGHT THROUGH EARLY
FRIDAY MORNING. SIMILAR TO LAST NIGHT..LOW CEILINGS AND FOG ARE
EXPECTED TO REDEVELOP OVERNIGHT AND AGAIN FRIDAY NIGHT.
DZ
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM CONFIDENCE WITH CEILINGS...LOW CONFIDENCE WITH POTENTIAL
FOR LIFR CEILINGS TONIGHT/EARLY FRIDAY MORNING.
* MEDIUM HIGH CONFIDENCE IN WIND DIRECTION AND SPEED.
* HIGH CONFIDENCE FOR FOG/MVFR VIS TONIGHT EARLY FRIDAY
MORNING...LOW CONFIDENCE WITH POTENTIAL FOR LIFR VIS.
DZ
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...TSRA LIKELY.
SUNDAY...CHC OF SHRA.
MONDAY-WEDNESDAY...VFR.
DZ
&&
.MARINE...
324 PM CDT
LOW PRESSURE SITTING ON THE MN-IA BORDER AT MID AFTERNOON WILL
MOVE ENE ALONG A STATIONARY FRONT DRAPED ACROSS CENTRAL LAKE MI
TONIGHT...WITH THE LOW REACHING CENTRAL LOWER MI BY DAWN. STRONG
LOW PRESSURE WILL REMAIN IN THE CENTRAL HIGH PLAINS TONIGHT AND
THEN MOVE NE FRI...REACHING SOUTHERN MN BY SAT MORNING. AS THIS
LOW CONTINUES NE TO THE WESTERN U.P. OF MI SAT...AND THEN ACROSS
LAKE SUPERIOR INTO ONTARIO SAT NIGHT IT WILL SWEEP A STRONG COLD
FRONT ACROSS THE UPPER MIDWEST AND INTO THE UPPER GREAT LAKES.
THIS LOW MOVES FURTHER OFF TO THE NE TOWARD SOUTHERN HUDSON BAY
SUN AND SUN NIGHT.
A STRONG S TO SW FLOW WILL PRECEDE THE PLAINS LOW AND ITS COLD
FRONT...BUT DUE TO THE VERY WARM AIR IT WILL CONTINUE TO SPREAD
ACROSS THE REGION IT WILL BE QUITE STABLE AT AND CLOSE TO THE
SURFACE OF THE LAKE WHICH WILL PREVENT THE STRONGER WINDS FROM
PENETRATING DOW TO NEAR THE LAKE SURFACE. HOWEVER...ONCE THE COLD
FRONT PASSES W TO E ACROSS THE LAKE DURING LATER SAT AND SAT
EVENING MUCH COOLER AIR WILL QUICKLY BE SWEPT ACROSS THE REGION.
WITH THE STILL RELATIVELY WARM LAKE WATER AND THE LOW LEVEL COLD
AIR ADVECTION BEHIND THE FRONT IT WILL TURN FROM A STABLE TO A
VERY UNSTABLE CONDITION AT THE LAKE SURFACE...WHICH WILL ALLOW
STRONG SW TO W WINDS BEHIND THE COLD FRONT AND IN THE WAKE OF THE
DEPARTING LOW TO EFFICIENTLY MIX ALL THE WAY DOWN TO THE LAKE
SURFACE. WHILE THERE MAY BE A LOW END GALE FORCE GUST OR TWO
OBSERVED SATURDAY NIGHT AFTER THE COLD FRONTAL PASSAGE...BASED ON
CURRENT MODEL GUIDANCE AN UPPER LIMIT OF 30KT SUSTAINED WINDS
APPEARS TO BE THE APPROPRIATE FORECAST.
MODELS GENERALLY AGREE IN MOVING THE LOW QUICKLY TO THE NE AND
NNE ACROSS ONTARIO TO NEAR SOUTHERN HUDSON BAY BY SUNDAY
NIGHT...THE GRADIENT ACROSS LAKE MI WILL BE RELAXING DURING THE
DAY SUN...WITH A CORRESPONDING GRADUAL DECREASE IN WIND SPEEDS
OCCURRING AS THE DAY PROGRESSES.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
522 PM CDT THU OCT 3 2013
.DISCUSSION...
303 PM CDT
SYNOPSIS...UNSETTLED WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT
A DRY WARMING TREND IS EXPECTED NEXT WEEK.
REST OF DAY AND TONIGHT...
A LOW PRESSURE TROUGH EXTENDS FROM THE PLAINS INTO SW WI WITH A
STATIONARY/WARM FRONT OVER SOUTHERN WI. A SHORTWAVE TROUGH IS ALSO
OVER MN/WI AND THE SHORTWAVE WILL PASS OVER IL LATER THIS AFTN. THE
STRONGEST PART OF THE SHORTWAVE AND SUBSEQUENT FORCING WILL STAY
NORTH OF THE CWA AND PASS OVER CENTRAL/SOUTHERN WI. EXPECTING THE
MAJORITY OF PRECIP TO STAY OVER WI CLOSER TO THE FORCING. HOWEVER
GIVEN RECENT RADAR TRENDS...THINKING THE NAM MAY BE ON TO SOMETHING
WITH MEASURABLE PRECIP ACROSS THE CWA LATE THIS AFTN THROUGH THIS
EVENING.
THE HRRR WOULD ALSO SUPPORT THIS THEORY AS WELL...THEREFORE PUT A
LINE OF SHRA/TSRA MOVING THROUGH NORTHERN IL AND INDIANA IN THE
GRIDS. OVERTIME HAVE THE SOUTHERN EXTENT OF THE LINE...SOUTH OF
I-80...WEAKENING. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT NORTH OVERNIGHT WITH THE WARM FRONT.
FOR SVR POTENTIAL...THINKING A COUPLE OF STORMS MAY PULSE UP TO
STRONG OR SVR...BUT OVERALL JUST EXPECTING GENERAL THUNDERSTORMS.
MOISTURE IS PLENTIFUL WITH DEWPOINTS AROUND 70 AND PWAT VALUES
AROUND 1.5 INCHES...2 STANDARD DEVIATIONS ABOVE NORMAL FOR OCTOBER.
SFC CAPE VALUES ARE 1000-2500 J/KG WITH 30 KT OF SHEAR. FORECAST
SOUNDINGS FEATURE SKINNY CAPE SO NOT EXPECTING LARGE HAIL...BUT A
WIND THREAT IS CERTAINLY POSSIBLE. SOME OF THE CELLS HAVE ALREADY
FEATURE BOW-ESQ CHARACTERISTICS. THEREFORE THINKING THE MAIN
THREATS WILL BE HEAVY RAIN AND GUSTY WINDS.
KEPT TEMPS A BIT WARMER TONIGHT AS THICK STRATUS SHOULD BE
PLENTIFUL. LOOKING AT LOW TEMPS IN THE MID 60S. WITH DEWPOINTS IN
THE MID 60S AS WELL...EXPECTING AREAS OF FOG AND POSSIBLE DENSE FOG
AGAIN AFTER MIDNIGHT THROUGH EARLY FRIDAY MORNING.
FRIDAY AND SATURDAY...
A STRONG SURFACE LOW EJECTS OUT OF THE ROCKIES TOMORROW AND PASSES
TO OUR NW THROUGH WI SATURDAY NIGHT. GUIDANCE STILL DIFFERS ON HOW
FAST THE LOW WILL PASS THROUGH THE REGION...BUT IN GENERAL EXPECTING
THE COLD FRONT TO IMPACT THE CWA SATURDAY AND SATURDAY NIGHT.
FOR FRIDAY...EXPECTING A PRIMARILY DRY DAY BUT COULD SEE A FEW
SHOWERS AND/OR STORMS ALONG THE IL/WI BORDER AS THE WARM FRONT
SHIFTS NORTH. ANOTHER HOT AND MUGGY DAY WITH HIGHS IN THE MID TO
UPPER 80S AND DEWPOINTS IN THE MID 60S. THERE IS A CONCERN SIMILAR
TO TODAY THAT IF THE STRATUS LINGERS TOO LONG...TEMPS COULD BE
COOLER THAN FORECAST. HOWEVER THE FRONT WILL START OUT FARTHER NORTH
TOMORROW AND THERE WILL BE BETTER MIXING...SO THINKING THE STRATUS
WILL BURN OFF FASTER THAN THIS MORNING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FORECAST CAPE VALUES OF
1000-1500 J/KG AND PWAT VALUES 1.5-1.75 INCHES. 0-6 KM SHEAR LOOKS
FAVORABLE FOR SEVERE WEATHER WITH VALUES OF 35-40 KT AHEAD OF THE
FRONT AND 50-70 KT ALONG THE FRONT. TIMING IS ALSO FAVORABLE AS
INSTABILITY CAN GROW ACROSS THE REGION BEFORE THE FRONT SLIDES
ACROSS. EXPECTING THE STRONGER STORMS AND PRECIP TO FALL ONCE AGAIN
OVER WI AS THE UPPER LEVEL JETS LEFT EXIT REGION WILL PROVIDE
ADDITIONAL LIFT.
EXTENDED...SUNDAY THROUGH WEDNESDAY...
THE UPPER LEVEL LOW PASSES OVER THE REGION LATE THIS WEEKEND AS THE
SURFACE LOW LIFTS NORTHEAST INTO QUEBEC. UPPER LEVEL RIDGING AND A
SURFACE HIGH MOVE OVER THE CWA BEFORE CONTINUING EAST AND REACHING
THE ATLANTIC COAST BY MID WEEK.
THE SURFACE LOW WILL PASS OVER NORTHERN LAKE MI SUNDAY WITH WRAP
AROUND SHOWERS POSSIBLE SUNDAY NIGHT/MONDAY MORNING. GUIDANCE DOES
DIFFER ON HOW QUICKLY THE LOW SHIFTS TO THE NE...AND THE SOUTHERN
EXTENT OF THE WRAP AROUND SHOWERS WILL DEPEND ON THE TRACK OF THE
LOW.
THE END OF THE WEEKEND WILL BE COOL BUT A GRADUAL WARM UP TO ABOVE
NORMAL TEMPS IS EXPECTED THROUGH MID NEXT WEEK AS THE HIGH BUILDS IN.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SHRA/TSRA INTO THIS EVENING.
* POSSIBILITY OF LOW END MVFR OR IFR CEILINGS DEVELOPING ONCE
AGAIN TONIGHT INTO FRIDAY MORNING.
* FOG WITH MVFR VIS TONIGHT/EARLY FRIDAY MORNING...POSSIBILITY FOR
IFR VIS.
DZ
//DISCUSSION...UPDATED 18Z...
COMPLEX FORECAST THIS PERIOD WITH ACTIVE WEATHER EXPECTED ACROSS
THE TERMINALS TODAY AND TONIGHT. AFTER THE DEPARTURE OF THE LOW
CEILINGS THIS MORNING...VFR CONDITIONS HAVE PREVAILED. ALTHOUGH AT
THIS TIME...LOW END MVFR CEILINGS HAVE REDEVELOPED. EXPECT THESE
LOWER CEILINGS TO BE IN PLACE OVER THE NEXT SEVERAL HOURS...WITH
AN IMPROVING TREND THEN LIKELY ONCE AGAIN LATER THIS AFTERNOON.
CONTINUE TO MONITOR A MID LEVEL FEATURE PROGRESSING EAST ACROSS
IOWA/MINNESOTA AS WELL AS A SURFACE TROUGH EXTENDING FROM IOWA
EAST INTO ILLINOIS. ITS THESE FEATURES WHICH WILL HELP CURRENT
ISOLATED -SHRA/-TSRA OVER FAR WESTERN ILLINOIS TO INCREASE IN
COVERAGE THIS AFTERNOON AND EARLY EVENING...AS THEY SHIFT EAST
THROUGH NORTHERN ILLINOIS. HAVE INCLUDED -SHRA IN THE TAF...WITH
-TSRA THEN ALSO POSSIBLE. EXPECT BEST TIME FRAME TO BE THIS
AFTERNOON THROUGH EARLY AFTERNOON WITH ANY DEVELOPMENT TO SHIFT
OUT OF THE AREA. FEEL THAT THE BULK OF ANY FURTHER PRECIP
DEVELOPMENT TONIGHT SHOULD REMAIN NORTH OF THE TERMINALS...BUT
WILL HAVE TO CONTINUE TO MONITOR LATER TRENDS AS THERE IS THE
POSSIBILITY FOR THIS LATER DEVELOPMENT TO REACH THE TERMINALS.
WITH A FAIRLY MOIST/WARM ENVIRONMENT STILL IN PLACE...FOG WILL
ONCE AGAIN BECOME AN ISSUE TONIGHT INTO EARLY FRIDAY. HAVE NOT
GONE TOO LOW WITH VIS AS CONFIDENCE IS LOW...MAINLY DUE TO THE
POTENTIAL FOR LINGERING PRECIP OVERNIGHT. THIS LIKEWISE PERTAINS
TO CEILINGS AS WELL...WITH A DEFINITE POSSIBILITY REMAINING FOR
LOWER CEILINGS ONCE AGAIN TONIGHT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM CONFIDENCE WITH CEILINGS...LOW CONFIDENCE WITH POTENTIAL
FOR LOW END MVFR OR IFR CEILINGS TONIGHT/EARLY FRIDAY MORNING.
* MEDIUM CONFIDENCE IN COVERAGE AND TIMING FOR SHRA/TSRA THIS
EVENING.
* HIGH CONFIDENCE FOR FOG/MVFR VIS TONIGHT EARLY FRIDAY
MORNING...LOW CONFIDENCE WITH POTENTIAL FOR IFR VIS.
DZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR VIS POSSIBLE..OTHERWISE VFR.
SATURDAY...TSRA LIKELY. GUSTY SW WIND.
SUNDAY...CHC OF SHRA. GUSTY SW WIND
MONDAY-WEDNESDAY...VFR.
KJB
&&
.MARINE...
324 PM CDT
LOW PRESSURE SITTING ON THE MN-IA BORDER AT MID AFTERNOON WILL
MOVE ENE ALONG A STATIONARY FRONT DRAPED ACROSS CENTRAL LAKE MI
TONIGHT...WITH THE LOW REACHING CENTRAL LOWER MI BY DAWN. STRONG
LOW PRESSURE WILL REMAIN IN THE CENTRAL HIGH PLAINS TONIGHT AND
THEN MOVE NE FRI...REACHING SOUTHERN MN BY SAT MORNING. AS THIS
LOW CONTINUES NE TO THE WESTERN U.P. OF MI SAT...AND THEN ACROSS
LAKE SUPERIOR INTO ONTARIO SAT NIGHT IT WILL SWEEP A STRONG COLD
FRONT ACROSS THE UPPER MIDWEST AND INTO THE UPPER GREAT LAKES.
THIS LOW MOVES FURTHER OFF TO THE NE TOWARD SOUTHERN HUDSON BAY
SUN AND SUN NIGHT.
A STRONG S TO SW FLOW WILL PRECEDE THE PLAINS LOW AND ITS COLD
FRONT...BUT DUE TO THE VERY WARM AIR IT WILL CONTINUE TO SPREAD
ACROSS THE REGION IT WILL BE QUITE STABLE AT AND CLOSE TO THE
SURFACE OF THE LAKE WHICH WILL PREVENT THE STRONGER WINDS FROM
PENETRATING DOW TO NEAR THE LAKE SURFACE. HOWEVER...ONCE THE COLD
FRONT PASSES W TO E ACROSS THE LAKE DURING LATER SAT AND SAT
EVENING MUCH COOLER AIR WILL QUICKLY BE SWEPT ACROSS THE REGION.
WITH THE STILL RELATIVELY WARM LAKE WATER AND THE LOW LEVEL COLD
AIR ADVECTION BEHIND THE FRONT IT WILL TURN FROM A STABLE TO A
VERY UNSTABLE CONDITION AT THE LAKE SURFACE...WHICH WILL ALLOW
STRONG SW TO W WINDS BEHIND THE COLD FRONT AND IN THE WAKE OF THE
DEPARTING LOW TO EFFICIENTLY MIX ALL THE WAY DOWN TO THE LAKE
SURFACE. WHILE THERE MAY BE A LOW END GALE FORCE GUST OR TWO
OBSERVED SATURDAY NIGHT AFTER THE COLD FRONTAL PASSAGE...BASED ON
CURRENT MODEL GUIDANCE AN UPPER LIMIT OF 30KT SUSTAINED WINDS
APPEARS TO BE THE APPROPRIATE FORECAST.
MODELS GENERALLY AGREE IN MOVING THE LOW QUICKLY TO THE NE AND
NNE ACROSS ONTARIO TO NEAR SOUTHERN HUDSON BAY BY SUNDAY
NIGHT...THE GRADIENT ACROSS LAKE MI WILL BE RELAXING DURING THE
DAY SUN...WITH A CORRESPONDING GRADUAL DECREASE IN WIND SPEEDS
OCCURRING AS THE DAY PROGRESSES.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
347 PM CDT THU OCT 3 2013
.DISCUSSION...
303 PM CDT
SYNOPSIS...UNSETTLED WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT
A DRY WARMING TREND IS EXPECTED NEXT WEEK.
REST OF DAY AND TONIGHT...
A LOW PRESSURE TROUGH EXTENDS FROM THE PLAINS INTO SW WI WITH A
STATIONARY/WARM FRONT OVER SOUTHERN WI. A SHORTWAVE TROUGH IS ALSO
OVER MN/WI AND THE SHORTWAVE WILL PASS OVER IL LATER THIS AFTN. THE
STRONGEST PART OF THE SHORTWAVE AND SUBSEQUENT FORCING WILL STAY
NORTH OF THE CWA AND PASS OVER CENTRAL/SOUTHERN WI. EXPECTING THE
MAJORITY OF PRECIP TO STAY OVER WI CLOSER TO THE FORCING. HOWEVER
GIVEN RECENT RADAR TRENDS...THINKING THE NAM MAY BE ON TO SOMETHING
WITH MEASURABLE PRECIP ACROSS THE CWA LATE THIS AFTN THROUGH THIS
EVENING.
THE HRRR WOULD ALSO SUPPORT THIS THEORY AS WELL...THEREFORE PUT A
LINE OF SHRA/TSRA MOVING THROUGH NORTHERN IL AND INDIANA IN THE
GRIDS. OVERTIME HAVE THE SOUTHERN EXTENT OF THE LINE...SOUTH OF
I-80...WEAKENING. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT NORTH OVERNIGHT WITH THE WARM FRONT.
FOR SVR POTENTIAL...THINKING A COUPLE OF STORMS MAY PULSE UP TO
STRONG OR SVR...BUT OVERALL JUST EXPECTING GENERAL THUNDERSTORMS.
MOISTURE IS PLENTIFUL WITH DEWPOINTS AROUND 70 AND PWAT VALUES
AROUND 1.5 INCHES...2 STANDARD DEVIATIONS ABOVE NORMAL FOR OCTOBER.
SFC CAPE VALUES ARE 1000-2500 J/KG WITH 30 KT OF SHEAR. FORECAST
SOUNDINGS FEATURE SKINNY CAPE SO NOT EXPECTING LARGE HAIL...BUT A
WIND THREAT IS CERTAINLY POSSIBLE. SOME OF THE CELLS HAVE ALREADY
FEATURE BOW-ESQ CHARACTERISTICS. THEREFORE THINKING THE MAIN
THREATS WILL BE HEAVY RAIN AND GUSTY WINDS.
KEPT TEMPS A BIT WARMER TONIGHT AS THICK STRATUS SHOULD BE
PLENTIFUL. LOOKING AT LOW TEMPS IN THE MID 60S. WITH DEWPOINTS IN
THE MID 60S AS WELL...EXPECTING AREAS OF FOG AND POSSIBLE DENSE FOG
AGAIN AFTER MIDNIGHT THROUGH EARLY FRIDAY MORNING.
FRIDAY AND SATURDAY...
A STRONG SURFACE LOW EJECTS OUT OF THE ROCKIES TOMORROW AND PASSES
TO OUR NW THROUGH WI SATURDAY NIGHT. GUIDANCE STILL DIFFERS ON HOW
FAST THE LOW WILL PASS THROUGH THE REGION...BUT IN GENERAL EXPECTING
THE COLD FRONT TO IMPACT THE CWA SATURDAY AND SATURDAY NIGHT.
FOR FRIDAY...EXPECTING A PRIMARILY DRY DAY BUT COULD SEE A FEW
SHOWERS AND/OR STORMS ALONG THE IL/WI BORDER AS THE WARM FRONT
SHIFTS NORTH. ANOTHER HOT AND MUGGY DAY WITH HIGHS IN THE MID TO
UPPER 80S AND DEWPOINTS IN THE MID 60S. THERE IS A CONCERN SIMILAR
TO TODAY THAT IF THE STRATUS LINGERS TOO LONG...TEMPS COULD BE
COOLER THAN FORECAST. HOWEVER THE FRONT WILL START OUT FARTHER NORTH
TOMORROW AND THERE WILL BE BETTER MIXING...SO THINKING THE STRATUS
WILL BURN OFF FASTER THAN THIS MORNING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FORECAST CAPE VALUES OF
1000-1500 J/KG AND PWAT VALUES 1.5-1.75 INCHES. 0-6 KM SHEAR LOOKS
FAVORABLE FOR SEVERE WEATHER WITH VALUES OF 35-40 KT AHEAD OF THE
FRONT AND 50-70 KT ALONG THE FRONT. TIMING IS ALSO FAVORABLE AS
INSTABILITY CAN GROW ACROSS THE REGION BEFORE THE FRONT SLIDES
ACROSS. EXPECTING THE STRONGER STORMS AND PRECIP TO FALL ONCE AGAIN
OVER WI AS THE UPPER LEVEL JETS LEFT EXIT REGION WILL PROVIDE
ADDITIONAL LIFT.
EXTENDED...SUNDAY THROUGH WEDNESDAY...
THE UPPER LEVEL LOW PASSES OVER THE REGION LATE THIS WEEKEND AS THE
SURFACE LOW LIFTS NORTHEAST INTO QUEBEC. UPPER LEVEL RIDGING AND A
SURFACE HIGH MOVE OVER THE CWA BEFORE CONTINUING EAST AND REACHING
THE ATLANTIC COAST BY MID WEEK.
THE SURFACE LOW WILL PASS OVER NORTHERN LAKE MI SUNDAY WITH WRAP
AROUND SHOWERS POSSIBLE SUNDAY NIGHT/MONDAY MORNING. GUIDANCE DOES
DIFFER ON HOW QUICKLY THE LOW SHIFTS TO THE NE...AND THE SOUTHERN
EXTENT OF THE WRAP AROUND SHOWERS WILL DEPEND ON THE TRACK OF THE
LOW.
THE END OF THE WEEKEND WILL BE COOL BUT A GRADUAL WARM UP TO ABOVE
NORMAL TEMPS IS EXPECTED THROUGH MID NEXT WEEK AS THE HIGH BUILDS IN.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LINGERING MVFR CEILINGS THIS AFTERNOON WITH VFR CEILINGS THEN
FORECAST THROUGH THE REST OF THE PERIOD...BUT WITH A POSSIBILITY
OF LOW END MVFR OR IFR CEILINGS DEVELOPING ONCE AGAIN TONIGHT
INTO FRIDAY MORNING.
* PREVAILING -SHRA/-TSRA EARLY THIS EVENING.
* FOG WITH MVFR VIS TONIGHT/EARLY FRIDAY MORNING...POSSIBILITY FOR
IFR VIS.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
COMPLEX FORECAST THIS PERIOD WITH ACTIVE WEATHER EXPECTED ACROSS
THE TERMINALS TODAY AND TONIGHT. AFTER THE DEPARTURE OF THE LOW
CEILINGS THIS MORNING...VFR CONDITIONS HAVE PREVAILED. ALTHOUGH AT
THIS TIME...LOW END MVFR CEILINGS HAVE REDEVELOPED. EXPECT THESE
LOWER CEILINGS TO BE IN PLACE OVER THE NEXT SEVERAL HOURS...WITH
AN IMPROVING TREND THEN LIKELY ONCE AGAIN LATER THIS AFTERNOON.
CONTINUE TO MONITOR A MID LEVEL FEATURE PROGRESSING EAST ACROSS
IOWA/MINNESOTA AS WELL AS A SURFACE TROUGH EXTENDING FROM IOWA
EAST INTO ILLINOIS. ITS THESE FEATURES WHICH WILL HELP CURRENT
ISOLATED -SHRA/-TSRA OVER FAR WESTERN ILLINOIS TO INCREASE IN
COVERAGE THIS AFTERNOON AND EARLY EVENING...AS THEY SHIFT EAST
THROUGH NORTHERN ILLINOIS. HAVE INCLUDED -SHRA IN THE TAF...WITH
-TSRA THEN ALSO POSSIBLE. EXPECT BEST TIME FRAME TO BE THIS
AFTERNOON THROUGH EARLY AFTERNOON WITH ANY DEVELOPMENT TO SHIFT
OUT OF THE AREA. FEEL THAT THE BULK OF ANY FURTHER PRECIP
DEVELOPMENT TONIGHT SHOULD REMAIN NORTH OF THE TERMINALS...BUT
WILL HAVE TO CONTINUE TO MONITOR LATER TRENDS AS THERE IS THE
POSSIBILITY FOR THIS LATER DEVELOPMENT TO REACH THE TERMINALS.
WITH A FAIRLY MOIST/WARM ENVIRONMENT STILL IN PLACE...FOG WILL
ONCE AGAIN BECOME AN ISSUE TONIGHT INTO EARLY FRIDAY. HAVE NOT
GONE TOO LOW WITH VIS AS CONFIDENCE IS LOW...MAINLY DUE TO THE
POTENTIAL FOR LINGERING PRECIP OVERNIGHT. THIS LIKEWISE PERTAINS
TO CEILINGS AS WELL...WITH A DEFINITE POSSIBILITY REMAINING FOR
LOWER CEILINGS ONCE AGAIN TONIGHT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE WITH CEILINGS...LOW CONFIDENCE WITH POTENTIAL
FOR LOW END MVFR OR IFR CEILINGS TONIGHT/EARLY FRIDAY MORNING.
* MEDIUM HIGH CONFIDENCE FOR -SHRA/-TSRA EARLY THIS
EVENING...MEDIUM CONFIDENCE ON TIMING.
* HIGH CONFIDENCE FOR FOG/MVFR VIS TONIGHT EARLY FRIDAY
MORNING...LOW CONFIDENCE WITH POTENTIAL FOR IFR VIS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR VIS POSSIBLE..OTHERWISE VFR.
SATURDAY...TSRA LIKELY. GUSTY SW WIND.
SUNDAY...CHC OF SHRA. GUSTY SW WIND
MONDAY-WEDNESDAY...VFR.
KJB
&&
.MARINE...
324 PM CDT
LOW PRESSURE SITTING ON THE MN-IA BORDER AT MID AFTERNOON WILL
MOVE ENE ALONG A STATIONARY FRONT DRAPED ACROSS CENTRAL LAKE MI
TONIGHT...WITH THE LOW REACHING CENTRAL LOWER MI BY DAWN. STRONG
LOW PRESSURE WILL REMAIN IN THE CENTRAL HIGH PLAINS TONIGHT AND
THEN MOVE NE FRI...REACHING SOUTHERN MN BY SAT MORNING. AS THIS
LOW CONTINUES NE TO THE WESTERN U.P. OF MI SAT...AND THEN ACROSS
LAKE SUPERIOR INTO ONTARIO SAT NIGHT IT WILL SWEEP A STRONG COLD
FRONT ACROSS THE UPPER MIDWEST AND INTO THE UPPER GREAT LAKES.
THIS LOW MOVES FURTHER OFF TO THE NE TOWARD SOUTHERN HUDSON BAY
SUN AND SUN NIGHT.
A STRONG S TO SW FLOW WILL PRECEDE THE PLAINS LOW AND ITS COLD
FRONT...BUT DUE TO THE VERY WARM AIR IT WILL CONTINUE TO SPREAD
ACROSS THE REGION IT WILL BE QUITE STABLE AT AND CLOSE TO THE
SURFACE OF THE LAKE WHICH WILL PREVENT THE STRONGER WINDS FROM
PENETRATING DOW TO NEAR THE LAKE SURFACE. HOWEVER...ONCE THE COLD
FRONT PASSES W TO E ACROSS THE LAKE DURING LATER SAT AND SAT
EVENING MUCH COOLER AIR WILL QUICKLY BE SWEPT ACROSS THE REGION.
WITH THE STILL RELATIVELY WARM LAKE WATER AND THE LOW LEVEL COLD
AIR ADVECTION BEHIND THE FRONT IT WILL TURN FROM A STABLE TO A
VERY UNSTABLE CONDITION AT THE LAKE SURFACE...WHICH WILL ALLOW
STRONG SW TO W WINDS BEHIND THE COLD FRONT AND IN THE WAKE OF THE
DEPARTING LOW TO EFFICIENTLY MIX ALL THE WAY DOWN TO THE LAKE
SURFACE. WHILE THERE MAY BE A LOW END GALE FORCE GUST OR TWO
OBSERVED SATURDAY NIGHT AFTER THE COLD FRONTAL PASSAGE...BASED ON
CURRENT MODEL GUIDANCE AN UPPER LIMIT OF 30KT SUSTAINED WINDS
APPEARS TO BE THE APPROPRIATE FORECAST.
MODELS GENERALLY AGREE IN MOVING THE LOW QUICKLY TO THE NE AND
NNE ACROSS ONTARIO TO NEAR SOUTHERN HUDSON BAY BY SUNDAY
NIGHT...THE GRADIENT ACROSS LAKE MI WILL BE RELAXING DURING THE
DAY SUN...WITH A CORRESPONDING GRADUAL DECREASE IN WIND SPEEDS
OCCURRING AS THE DAY PROGRESSES.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
DISCLAIMER: NWS FACEBOOK...TWITTER AND YOUTUBE SITES ARE NOT
CONSIDERED OFFICIAL MEANS OF DISSEMINATING WEATHER INFORMATION
AND SHOULD NOT BE COUNTED ON AS SUCH.
OFFICIAL NWS.NOAA.GOV WEB SITES ARE MOST RELIABLE IN PROVIDING
TIMELY DELIVERY OF DATA AND PRODUCTS BUT EVEN THESE SOURCES
CANNOT BE GUARANTEED DUE TO THE NATURE OF THE INTERNET.
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
303 PM CDT THU OCT 3 2013
.DISCUSSION...
303 PM CDT
SYNOPSIS...UNSETTLED WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT
A DRY WARMING TREND IS EXPECTED NEXT WEEK.
REST OF DAY AND TONIGHT...
A LOW PRESSURE TROUGH EXTENDS FROM THE PLAINS INTO SW WI WITH A
STATIONARY/WARM FRONT OVER SOUTHERN WI. A SHORTWAVE TROUGH IS ALSO
OVER MN/WI AND THE SHORTWAVE WILL PASS OVER IL LATER THIS AFTN. THE
STRONGEST PART OF THE SHORTWAVE AND SUBSEQUENT FORCING WILL STAY
NORTH OF THE CWA AND PASS OVER CENTRAL/SOUTHERN WI. EXPECTING THE
MAJORITY OF PRECIP TO STAY OVER WI CLOSER TO THE FORCING. HOWEVER
GIVEN RECENT RADAR TRENDS...THINKING THE NAM MAY BE ON TO SOMETHING
WITH MEASURABLE PRECIP ACROSS THE CWA LATE THIS AFTN THROUGH THIS
EVENING.
THE HRRR WOULD ALSO SUPPORT THIS THEORY AS WELL...THEREFORE PUT A
LINE OF SHRA/TSRA MOVING THROUGH NORTHERN IL AND INDIANA IN THE
GRIDS. OVERTIME HAVE THE SOUTHERN EXTENT OF THE LINE...SOUTH OF
I-80...WEAKENING. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
LIFT NORTH OVERNIGHT WITH THE WARM FRONT.
FOR SVR POTENTIAL...THINKING A COUPLE OF STORMS MAY PULSE UP TO
STRONG OR SVR...BUT OVERALL JUST EXPECTING GENERAL THUNDERSTORMS.
MOISTURE IS PLENTIFUL WITH DEWPOINTS AROUND 70 AND PWAT VALUES
AROUND 1.5 INCHES...2 STANDARD DEVIATIONS ABOVE NORMAL FOR OCTOBER.
SFC CAPE VALUES ARE 1000-2500 J/KG WITH 30 KT OF SHEAR. FORECAST
SOUNDINGS FEATURE SKINNY CAPE SO NOT EXPECTING LARGE HAIL...BUT A
WIND THREAT IS CERTAINLY POSSIBLE. SOME OF THE CELLS HAVE ALREADY
FEATURE BOW-ESQ CHARACTERISTICS. THEREFORE THINKING THE MAIN
THREATS WILL BE HEAVY RAIN AND GUSTY WINDS.
KEPT TEMPS A BIT WARMER TONIGHT AS THICK STRATUS SHOULD BE
PLENTIFUL. LOOKING AT LOW TEMPS IN THE MID 60S. WITH DEWPOINTS IN
THE MID 60S AS WELL...EXPECTING AREAS OF FOG AND POSSIBLE DENSE FOG
AGAIN AFTER MIDNIGHT THROUGH EARLY FRIDAY MORNING.
FRIDAY AND SATURDAY...
A STRONG SURFACE LOW EJECTS OUT OF THE ROCKIES TOMORROW AND PASSES
TO OUR NW THROUGH WI SATURDAY NIGHT. GUIDANCE STILL DIFFERS ON HOW
FAST THE LOW WILL PASS THROUGH THE REGION...BUT IN GENERAL EXPECTING
THE COLD FRONT TO IMPACT THE CWA SATURDAY AND SATURDAY NIGHT.
FOR FRIDAY...EXPECTING A PRIMARILY DRY DAY BUT COULD SEE A FEW
SHOWERS AND/OR STORMS ALONG THE IL/WI BORDER AS THE WARM FRONT
SHIFTS NORTH. ANOTHER HOT AND MUGGY DAY WITH HIGHS IN THE MID TO
UPPER 80S AND DEWPOINTS IN THE MID 60S. THERE IS A CONCERN SIMILAR
TO TODAY THAT IF THE STRATUS LINGERS TOO LONG...TEMPS COULD BE
COOLER THAN FORECAST. HOWEVER THE FRONT WILL START OUT FARTHER NORTH
TOMORROW AND THERE WILL BE BETTER MIXING...SO THINKING THE STRATUS
WILL BURN OFF FASTER THAN THIS MORNING.
SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH FORECAST CAPE VALUES OF
1000-1500 J/KG AND PWAT VALUES 1.5-1.75 INCHES. 0-6 KM SHEAR LOOKS
FAVORABLE FOR SEVERE WEATHER WITH VALUES OF 35-40 KT AHEAD OF THE
FRONT AND 50-70 KT ALONG THE FRONT. TIMING IS ALSO FAVORABLE AS
INSTABILITY CAN GROW ACROSS THE REGION BEFORE THE FRONT SLIDES
ACROSS. EXPECTING THE STRONGER STORMS AND PRECIP TO FALL ONCE AGAIN
OVER WI AS THE UPPER LEVEL JETS LEFT EXIT REGION WILL PROVIDE
ADDITIONAL LIFT.
EXTENDED...SUNDAY THROUGH WEDNESDAY...
THE UPPER LEVEL LOW PASSES OVER THE REGION LATE THIS WEEKEND AS THE
SURFACE LOW LIFTS NORTHEAST INTO QUEBEC. UPPER LEVEL RIDGING AND A
SURFACE HIGH MOVE OVER THE CWA BEFORE CONTINUING EAST AND REACHING
THE ATLANTIC COAST BY MID WEEK.
THE SURFACE LOW WILL PASS OVER NORTHERN LAKE MI SUNDAY WITH WRAP
AROUND SHOWERS POSSIBLE SUNDAY NIGHT/MONDAY MORNING. GUIDANCE DOES
DIFFER ON HOW QUICKLY THE LOW SHIFTS TO THE NE...AND THE SOUTHERN
EXTENT OF THE WRAP AROUND SHOWERS WILL DEPEND ON THE TRACK OF THE
LOW.
THE END OF THE WEEKEND WILL BE COOL BUT A GRADUAL WARM UP TO ABOVE
NORMAL TEMPS IS EXPECTED THROUGH MID NEXT WEEK AS THE HIGH BUILDS IN.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LINGERING MVFR CEILINGS THIS AFTERNOON WITH VFR CEILINGS THEN
FORECAST THROUGH THE REST OF THE PERIOD...BUT WITH A POSSIBILITY
OF LOW END MVFR OR IFR CEILINGS DEVELOPING ONCE AGAIN TONIGHT
INTO FRIDAY MORNING.
* PREVAILING -SHRA/-TSRA EARLY THIS EVENING.
* FOG WITH MVFR VIS TONIGHT/EARLY FRIDAY MORNING...POSSIBILITY FOR
IFR VIS.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
COMPLEX FORECAST THIS PERIOD WITH ACTIVE WEATHER EXPECTED ACROSS
THE TERMINALS TODAY AND TONIGHT. AFTER THE DEPARTURE OF THE LOW
CEILINGS THIS MORNING...VFR CONDITIONS HAVE PREVAILED. ALTHOUGH AT
THIS TIME...LOW END MVFR CEILINGS HAVE REDEVELOPED. EXPECT THESE
LOWER CEILINGS TO BE IN PLACE OVER THE NEXT SEVERAL HOURS...WITH
AN IMPROVING TREND THEN LIKELY ONCE AGAIN LATER THIS AFTERNOON.
CONTINUE TO MONITOR A MID LEVEL FEATURE PROGRESSING EAST ACROSS
IOWA/MINNESOTA AS WELL AS A SURFACE TROUGH EXTENDING FROM IOWA
EAST INTO ILLINOIS. ITS THESE FEATURES WHICH WILL HELP CURRENT
ISOLATED -SHRA/-TSRA OVER FAR WESTERN ILLINOIS TO INCREASE IN
COVERAGE THIS AFTERNOON AND EARLY EVENING...AS THEY SHIFT EAST
THROUGH NORTHERN ILLINOIS. HAVE INCLUDED -SHRA IN THE TAF...WITH
-TSRA THEN ALSO POSSIBLE. EXPECT BEST TIME FRAME TO BE THIS
AFTERNOON THROUGH EARLY AFTERNOON WITH ANY DEVELOPMENT TO SHIFT
OUT OF THE AREA. FEEL THAT THE BULK OF ANY FURTHER PRECIP
DEVELOPMENT TONIGHT SHOULD REMAIN NORTH OF THE TERMINALS...BUT
WILL HAVE TO CONTINUE TO MONITOR LATER TRENDS AS THERE IS THE
POSSIBILITY FOR THIS LATER DEVELOPMENT TO REACH THE TERMINALS.
WITH A FAIRLY MOIST/WARM ENVIRONMENT STILL IN PLACE...FOG WILL
ONCE AGAIN BECOME AN ISSUE TONIGHT INTO EARLY FRIDAY. HAVE NOT
GONE TOO LOW WITH VIS AS CONFIDENCE IS LOW...MAINLY DUE TO THE
POTENTIAL FOR LINGERING PRECIP OVERNIGHT. THIS LIKEWISE PERTAINS
TO CEILINGS AS WELL...WITH A DEFINITE POSSIBILITY REMAINING FOR
LOWER CEILINGS ONCE AGAIN TONIGHT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE WITH CEILINGS...LOW CONFIDENCE WITH POTENTIAL
FOR LOW END MVFR OR IFR CEILINGS TONIGHT/EARLY FRIDAY MORNING.
* MEDIUM HIGH CONFIDENCE FOR -SHRA/-TSRA EARLY THIS
EVENING...MEDIUM CONFIDENCE ON TIMING.
* HIGH CONFIDENCE FOR FOG/MVFR VIS TONIGHT EARLY FRIDAY
MORNING...LOW CONFIDENCE WITH POTENTIAL FOR IFR VIS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR VIS POSSIBLE..OTHERWISE VFR.
SATURDAY...TSRA LIKELY. GUSTY SW WIND.
SUNDAY...CHC OF SHRA. GUSTY SW WIND
MONDAY-WEDNESDAY...VFR.
KJB
&&
.MARINE...
315 AM CDT
THE MAIN WEATHER CONCERNS OVER THE LAKE CONTINUE TO FOCUS ON THE
EVOLUTION OF A STORM SYSTEM EXPECTED TO MOVE ACROSS THE
UPPER MIDWEST AND THE UPPER GREAT LAKES THIS WEEKEND.
IT STILL APPEARS THAT A WARM FRONT WILL SLOWLY LIFT NORTHWARD ACROSS
LAKE MICHIGAN OVER THE NEXT COUPLE DAYS...LIKELY BECOMING NEARLY
STATIONARY FOR A PERIOD SOMEWHERE ACROSS THE CENTRAL PORTION OF THE
LAKE. THE SURFACE LOW ITSELF WILL MATURE SATURDAY ACROSS THE UPPER
MISSISSIPPI VALLEY. THIS PROCESS WILL ALLOW EAST-NORTHEASTERLY WINDS
TO INCREASE ACROSS NORTHERN LAKE MICHIGAN TONIGHT AND ON FRIDAY...TO
THE NORTH OF THE SURFACE WARM FRONT. MEANWHILE...SOUTH OF THE
FRONT...SOUTHERLY FLOW WILL SETT UP. WITH TIME...THE LOW WILL LIFT
EAST-NORTHEASTWARD ACROSS THE UPPER GREAT LAKES REGION INTO SUNDAY.
ONCE THIS OCCURS...A DECENT COLD FRONT SHOULD BE SWEPT ACROSS THE
LAKE BY SUNDAY. A DECENT SHOT OF COLD AIR IN THE WAKE OF THIS FRONT
SHOULD SUPPORT SOME 20 TO 25 KT WEST-SOUTHWESTERLY WINDS FOR A
PERIOD SATURDAY NIGHT AND SUNDAY...WITH GUSTS TO 30 KT ALSO
POSSIBLE.
THE OTHER CONCERN OVER THE WEEKEND IS THE THREAT FOR WATER SPOUTS.
FOLLOWING THE COLD FRONTAL PASSAGE...IT APPEARS THAT SOME COLD AIR
WILL MOVE OVER THE LAKE SUNDAY AND SUNDAY NIGHT AS THE UPPER LOW
MOVES OVERHEAD. GIVEN THE CURRENT LAKE TEMPS...THIS COLD AIR MASS
COULD SETUP FAVORABLE CONDITIONS FOR WATER SPOUTS...PARTICULARLY LATE
SUNDAY AND SUNDAY NIGHT. I HAVE NOT INCLUDED THE MENTION OF THIS IN
THE LATEST FORECAST...MAINLY DUE TO UNCERTAINTIES ON THE EXACT TRACK
OF THE SYSTEM AND THE AMOUNT OF COLD AIR INTO SUNDAY NIGHT...BUT
LATER FORECASTS MAY NEED TO ADD THE MENTION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 PM CDT THU OCT 3 2013
.DISCUSSION...
336 AM CDT
I FEEL LIKE A KID COMING HOME FROM THEIR FIRST DAY OF SCHOOL WITH A
MILLION THINGS TO TELL THEIR PARENTS ABOUT...EXCEPT I`VE GOT ABOUT A
MILLION FORECAST THINGS TO TALK ABOUT THIS MORNING. HIGHLIGHTS
INCLUDE TEMPS AND THUNDERSTORM CHANCES THE NEXT FEW DAYS ALONG WITH
STRATUS/FOG POTENTIAL.
FIRST UP...PRECIP/TSTM CHANCES TODAY. GUIDANCE HAS BEEN REALLY OF
VERY LITTLE HELP THUS FAR TONIGHT AS CONVECTION HAS BEEN SPOTTY
OVER MOST OF IL/IN WHERE DAY AFTER DAY NOW MODELS HAVE HAD A
STRONG QPF SIGNAL LATE TONIGHT INTO THURSDAY MORNING. THE RAP/HRRR
ARE KEYING IN ON SHORTWAVE ENERGY OVER EASTERN KS TO PRODUCE A
CONVECTIVE COMPLEX MOVING INTO N IL THIS AFTERNOON...BUT THE
SHORTWAVE ENERGY OVER THE PLAINS SEEMS TO BE MORE FOCUSED WITH THE
MCV OVER SE NE THAT IS INCHING MORE SOUTHEASTWARD. ANOTHER
PRONOUNCED SHORTWAVE OVER WISCONSIN IS PUSHING EASTWARD AND LIKELY
TO ONLY PROVIDE A GLANCING BLOW OF LARGE SCALE ASCENT IN OUR CWA
THIS AFTERNOON. THE SURFACE WARM FRONT AND BETTER SFC FOCUS FOR
CONVECTION IS LIFTING NORTH INTO WISCONSIN AND SHOULD BE OUT OF
THE AREA BY AROUND SUNRISE...LEAVING VERY LITTLE TO HANG MY HAT ON
FORCING-WISE FOR CONVECTION THIS AFTERNOON. GIVEN THE PROGGED
MODERATE INSTABILITY WITH LITTLE INHIBITION AND WEAK ASCENT WITH
VARIOUS SUBTLE SHORTWAVES THINK THAT ISOLATED TO SCATTERED
SHOWERS/STORMS WILL DOT THE AREA THROUGH THE DAY...BUT HARD TO
ENVISION A SCENARIO WHERE STORMS BECOME WELL ORGANIZED AND COVERAGE
HIGH ENOUGH TO JUSTIFY REALLY BIG POPS TODAY.
OTHER HEADACHE TODAY WILL BE WITH STRATUS/CLOUD COVER AND SUBSEQUENT
EFFECT ON TEMPERATURES. MID-HIGH CLOUDS ARE MASKING THE LOW
STUFF...BUT IT APPEARS THAT STRATUS DECK IS BLOSSOMING AGAIN THIS
MORNING SOUTH OF THE WARM FRONT WHICH WILL NO DOUBT TAKE TIME TO
BURN OFF. WHERE POCKETS OF THE GREATEST HEATING/SUNSHINE OCCUR TODAY
HIGHS SHOULD REACH INTO THE LOW 80S WITH MID/UPPER 70S WHERE STRATUS
HANGS ON OR IS SLOWEST TO BURN OFF.
STRONG UPPER LEVEL JET WILL COME NOSING INTO THE PLAINS AND MID
MISSISSIPPI VALLEY TONIGHT WITH LEFT EXIT REGION OF THAT JET NOSING
INTO FAR NORTHERN ILLINOIS AND ESPECIALLY WISCONSIN TONIGHT. THE
WARM FRONT SHOULD BE NORTH OF THE STATE LINE...SO CONCEPTUALLY THAT
SHOULD PLACE THE HIGHEST CONVECTIVE CHANCES IN WISCONSIN WHERE
STRONGEST ISENTROPIC ASCENT WILL OCCUR COUPLED WITH STRONGER UPPER
LEVEL DIVERGENCE IN THE LEFT EXIT REGION OF THE JET. OUR NORTHERN
COUNTIES ARE CLOSE ENOUGH TO THIS SET UP TO WARRANT CHANCE POPS
TONIGHT BUT WOULD THINK THE MAIN SHOW WILL BE NORTH. CERTAINLY
PLAUSIBLE THAT STRATUS AND SOME FOG COULD RE-DEVELOP IN THE WARM
SECTOR TONIGHT AND SKY FORECAST IS LOW CONFIDENCE AS ANOTHER LOW OVC
DECK COULD BLOSSOM OVERNIGHT IN THE JUICY MID 60 DEWPOINT AIRMASS.
THIS LEADS INTO THE UNCERTAINTIES WITH FRIDAY`S FORECAST. ASSUMING
WE DON`T SPEND MOST OF FRIDAY MORNING TRYING TO BURN OFF A STRATUS
DECK...THEN THE POTENTIAL IS THERE FOR TEMPS TO REALLY GET OUT OF
HAND FRIDAY. MORNING LOWS IN THE MID TO UPPER 60S WILL PROVIDE A
NICE SPRING BOARD FOR TEMPS TO CLIMB INTO THE 80S...POSSIBLY
MID-UPPER 80S IF WE DON`T HAVE TO WASTE ANY OF OUR RAPIDLY
SHORTENING SUNLIGHT ON THE STRATUS. LIKE TUESDAY...MORE CLOUDS COULD
RESULT IN A SIZABLE FORECAST BUST. PRECIP-WISE...WE WILL BE WARM AND
UNSTABLE BUT BETTER FORCING SHOULD BE NORTH OF THE WARM FRONT IN
WISCONSIN AND WELL WEST OF THE CWA IN THE EASTERN PLAINS AND CORN
BELT WHERE A BIG SEVERE WEATHER EVENT COULD UNFOLD FRI AFTERNOON AND
EVENING. OBVIOUSLY OUR PRECIP THREAT ISNT ZERO...BUT BARRING ANY
UNFORESEEN MESOSCALE DEVELOPMENT THURSDAY NIGHT SHOULD BE VERY LOW
SYNOPTICALLY FRIDAY INTO FRIDAY EVENING.
ITS UNCLEAR HOW MUCH OF THE LEFTOVER`S OF IOWA`S POTENTIAL SEVERE
WEATHER EVENT WILL SURVIVE THROUGH THE NIGHT TO MAKE IT INTO OUR
AREA LATE AT NIGHT OR SATURDAY MORNING. GIVEN THE STORM SYSTEM WILL
BEGIN TO OCCLUDE AND FORCING NOT TREMENDOUS WOULD TEND TO THINK THAT
A SUBSTANTIAL WEAKENING IF NOT OUTRIGHT DISSIPATION OF THIS
CONVECTION COULD OCCUR BEFORE REACHING OUR CWA...BUT CERTAINLY
CHANCE POPS ARE WORTHY.
HUGE DIFFERENCES ARISE BETWEEN MOST OF THE GLOBAL MODELS AND THE
WRF-NAM AND SOME OF THE OTHER CONVECTIVE ALLOWING REGIONAL MODELS.
THE GLOBAL MODELS ARE GENERALLY ALL SLOWER WITH THE UPPER LOW AND
ASSOCIATED COLD FRONT MOVING THROUGH OUR CWA. THE SYSTEM WAS STILL
JUST OFFSHORE AT 00Z WHICH WOULD MAKE ME PUT A FEW MORE EGGS IN THE
BASKET OF THE GLOBAL MODELS...PLUS THESE BIGGER WESTERN SYSTEMS
FREQUENTLY END UP VERIFYING THE SLOWER END OF THE GUIDANCE ENVELOPE.
GIVEN THIS REASONING...HAVE FOLLOWED A GFS/ECMWF COMPROMISE WHICH
KEEPS OUR CWA IN THE WARM/HUMID SECTOR OF THE SYSTEM SATURDAY. THE
EC/GFS ARE A BIT SLOWER TO OCCLUDE THE STORM AND FORECAST A LITTLE
BETTER LOOKING OF A SHEAR PROFILE FOR SATURDAY THAN WHAT THEY SHOWED
YESTERDAY...BUT STILL LOOKS LIKE MODERATE SHEAR/WEAK-MODERATE
INSTABILITY SET-UP THAT DOESN`T EXACTLY SCREAM SEVERE WEATHER
POTENTIAL SATURDAY AFTERNOON. CERTAIN SOME THREAT OF DAMAGING WIND
COULD EXIST IF SQUALL LINE DEVELOPS...BUT UNLESS FORECASTED
SHEAR/INSTABILITY PROFILES IMPROVED MARKEDLY FOR SATURDAY OUR SEVERE
WEATHER THREAT LOOKS MARGINAL.
SUNDAY LOOKS MUCH MUCH COLDER WITH HIGHS POTENTIALLY HOLDING IN THE
50S...BUT UPPER LOW LOOKS TO GET CUT OFF FROM THE MAIN POLAR BRANCH
OF THE JET PRECLUDING ANY HUGE EARLY SEASON COLD SNAP. ONCE THE
CLOSED LOW WOBBLES EAST OF THE AREA TEMPS WILL QUICKLY MODERATE TO
AVERAGE AND LIKELY ABOVE AVERAGE LEVELS AGAIN NEXT WEEK. TIMING OF
THIS UPPER LOWS DEPARTURE AND SUBSEQUENT WARM UP WILL PROBABLY BE AN
ITEM UP FOR DEBATE AMONG THE MEDIUM RANGE MODELS THE NEXT FEW DAYS
AS CUT OFF LOWS LIKE THIS AREN`T TYPICALLY A STRONG SUIT OF THE
MODELS.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LINGERING LOW END MVFR CEILINGS EARLY THIS AFTERNOON WITH VFR
CEILINGS THEN FORECAST THROUGH THE REST OF THE PERIOD...BUT WITH
A POSSIBILITY OF LOW END MVFR OR IFR CEILINGS DEVELOPING ONCE
AGAIN TONIGHT INTO FRIDAY MORNING.
* PREVAILING -SHRA/-TSRA THIS EVENING.
* FOG WITH MVFR VIS TONIGHT/EARLY FRIDAY MORNING...POSSIBILITY FOR
IFR VIS.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
COMPLEX FORECAST THIS PERIOD WITH ACTIVE WEATHER EXPECTED ACROSS
THE TERMINALS TODAY AND TONIGHT. AFTER THE DEPARTURE OF THE LOW
CEILINGS THIS MORNING...VFR CONDITIONS HAVE PREVAILED. ALTHOUGH AT
THIS TIME...LOW END MVFR CEILINGS HAVE REDEVELOPED. EXPECT THESE
LOWER CEILINGS TO BE IN PLACE OVER THE NEXT SEVERAL HOURS...WITH
AN IMPROVING TREND THEN LIKELY ONCE AGAIN LATER THIS AFTERNOON.
CONTINUE TO MONITOR A MID LEVEL FEATURE PROGRESSING EAST ACROSS
IOWA/MINNESOTA AS WELL AS A SURFACE TROUGH EXTENDING FROM IOWA
EAST INTO ILLINOIS. ITS THESE FEATURES WHICH WILL HELP CURRENT
ISOLATED -SHRA/-TSRA OVER FAR WESTERN ILLINOIS TO INCREASE IN
COVERAGE THIS AFTERNOON AND EARLY EVENING...AS THEY SHIFT EAST
THROUGH NORTHERN ILLINOIS. HAVE INCLUDED -SHRA IN THE TAF...WITH
-TSRA THEN ALSO POSSIBLE. EXPECT BEST TIME FRAME TO BE THIS
AFTERNOON THROUGH EARLY AFTERNOON WITH ANY DEVELOPMENT TO SHIFT
OUT OF THE AREA. FEEL THAT THE BULK OF ANY FURTHER PRECIP
DEVELOPMENT TONIGHT SHOULD REMAIN NORTH OF THE TERMINALS...BUT
WILL HAVE TO CONTINUE TO MONITOR LATER TRENDS AS THERE IS THE
POSSIBILITY FOR THIS LATER DEVELOPMENT TO REACH THE TERMINALS.
WITH A FAIRLY MOIST/WARM ENVIRONMENT STILL IN PLACE...FOG WILL
ONCE AGAIN BECOME AN ISSUE TONIGHT INTO EARLY FRIDAY. HAVE NOT
GONE TOO LOW WITH VIS AS CONFIDENCE IS LOW...MAINLY DUE TO THE
POTENTIAL FOR LINGERING PRECIP OVERNIGHT. THIS LIKEWISE PERTAINS
TO CEILINGS AS WELL...WITH A DEFINITE POSSIBILITY REMAINING FOR
LOWER CEILINGS ONCE AGAIN TONIGHT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE WITH CEILINGS...LOW CONFIDENCE WITH POTENTIAL
FOR LOW END MVFR OR IFR CEILINGS TONIGHT/EARLY FRIDAY MORNING.
* MEDIUM HIGH CONFIDENCE FOR -SHRA/-TSRA THIS EVENING...MEDIUM
CONFIDENCE ON TIMING.
* HIGH CONFIDENCE FOR FOG/MVFR VIS TONIGHT EARLY FRIDAY
MORNING...LOW CONFIDENCE WITH POTENTIAL FOR IFR VIS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR VIS POSSIBLE..OTHERWISE VFR.
SATURDAY...TSRA LIKELY. GUSTY SW WIND.
SUNDAY...CHC OF SHRA. GUSTY SW WIND
MONDAY-WEDNESDAY...VFR.
KJB
&&
.MARINE...
315 AM CDT
THE MAIN WEATHER CONCERNS OVER THE LAKE CONTINUE TO FOCUS ON THE
EVOLUTION OF A STORM SYSTEM EXPECTED TO MOVE ACROSS THE
UPPER MIDWEST AND THE UPPER GREAT LAKES THIS WEEKEND.
IT STILL APPEARS THAT A WARM FRONT WILL SLOWLY LIFT NORTHWARD ACROSS
LAKE MICHIGAN OVER THE NEXT COUPLE DAYS...LIKELY BECOMING NEARLY
STATIONARY FOR A PERIOD SOMEWHERE ACROSS THE CENTRAL PORTION OF THE
LAKE. THE SURFACE LOW ITSELF WILL MATURE SATURDAY ACROSS THE UPPER
MISSISSIPPI VALLEY. THIS PROCESS WILL ALLOW EAST-NORTHEASTERLY WINDS
TO INCREASE ACROSS NORTHERN LAKE MICHIGAN TONIGHT AND ON FRIDAY...TO
THE NORTH OF THE SURFACE WARM FRONT. MEANWHILE...SOUTH OF THE
FRONT...SOUTHERLY FLOW WILL SETT UP. WITH TIME...THE LOW WILL LIFT
EAST-NORTHEASTWARD ACROSS THE UPPER GREAT LAKES REGION INTO SUNDAY.
ONCE THIS OCCURS...A DECENT COLD FRONT SHOULD BE SWEPT ACROSS THE
LAKE BY SUNDAY. A DECENT SHOT OF COLD AIR IN THE WAKE OF THIS FRONT
SHOULD SUPPORT SOME 20 TO 25 KT WEST-SOUTHWESTERLY WINDS FOR A
PERIOD SATURDAY NIGHT AND SUNDAY...WITH GUSTS TO 30 KT ALSO
POSSIBLE.
THE OTHER CONCERN OVER THE WEEKEND IS THE THREAT FOR WATER SPOUTS.
FOLLOWING THE COLD FRONTAL PASSAGE...IT APPEARS THAT SOME COLD AIR
WILL MOVE OVER THE LAKE SUNDAY AND SUNDAY NIGHT AS THE UPPER LOW
MOVES OVERHEAD. GIVEN THE CURRENT LAKE TEMPS...THIS COLD AIR MASS
COULD SETUP FAVORABLE CONDITIONS FOR WATER SPOUTS...PARTICULARLY LATE
SUNDAY AND SUNDAY NIGHT. I HAVE NOT INCLUDED THE MENTION OF THIS IN
THE LATEST FORECAST...MAINLY DUE TO UNCERTAINTIES ON THE EXACT TRACK
OF THE SYSTEM AND THE AMOUNT OF COLD AIR INTO SUNDAY NIGHT...BUT
LATER FORECASTS MAY NEED TO ADD THE MENTION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1244 PM CDT Thu Oct 3 2013
.DISCUSSION...
ISSUED 1024 AM CDT Thu Oct 3 2013
One short-wave trough is currently rippling northward into
northern Illinois, while a second wave is noted on water vapor
imagery further southwest over western Missouri. Showers/storms
associated with the first feature have primarily lifted north of
the KILX CWA...leaving behind partly sunny and dry conditions for
the time being. Meanwhile, the second wave is triggering scattered
convection across northern Missouri/southern Iowa. This activity
will track E/NE into portions of central Illinois this afternoon
and evening. Latest runs of both the NAM and HRRR suggest
convection will spread across mainly locations along and north of
a Jacksonville to Rantoul line. Based on model data and current
radar/satellite trends, have focused highest POPs across the
northern CWA this afternoon/evening...with only slight chances
featured south of the I-72 corridor. Zone update has already been
issued.
Barnes
&&
.AVIATION...
ISSUED 1244 PM CDT Thu Oct 3 2013
Diurnal CU-field continues to blossom in the warm/humid airmass
across central Illinois early this afternoon. MVFR ceilings will
gradually rise into the VFR category by mid afternoon. Current
radar analysis shows a line of convection from near Havana to
Jacksonville that will track northeastward and potentially impact
KSPI over the next hour. Have included a TEMPO group for thunder
to cover this. Elsewhere...have opted to only mention VCTS this
afternoon into the early evening. Any scattered showers/storms
will gradually dissipate and lift northward out of the area after
03z...so will drop mention of convection after that. Main issue
overnight will be the possible development of fog. Forecast
soundings and numeric guidance hint that light winds within the
humid low-level airmass will once again lead to fog overnight.
Have included visbys down to around 3 to 4SM accordingly. After
that...breezy and dry weather is expected by Friday morning, with
southerly winds gusting to between 15 and 20kt.
Barnes
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT Thu Oct 3 2013
SHORT TERM...Today through Sunday night
Some fog and stratus clouds below 1k ft over parts of central IL
early this morning, though not nearly as widespread as past few
days due to a bit stronger south winds and more mid level clouds
around. Patchy fog should lift by 15Z/10 am this morning. Short
range models continue to develop showers and a few thunderstorms
across central IL during this morning due to short waves lifting
up across IL and then diminish this afternoon as short wave exits
east of IL by sunset. Radar mosaic recently showing some showers
appearing west of I-57 and lifting nne. Will carry scattered
showers this morning and be more likely from I-74 north today.
Have highs in the low to mid 80s, but guidance has been too warm
past few days especially over cloudier areas of eastern/se IL,
so kept these areas a few degrees cooler today.
Somewhat of a lull tonight and Friday with just isolated
convection around as best forcing is north of MN/WI/MI and also
have a weak disturbance over the mid MS and lower OH valleys where
isolated convection possible Friday se of I-70. Lows tonight
mostly in the mid 60s. Highs Friday in the mid to upper 80s with
breezy ssw winds.
Favored the slower 00Z ECMWF and GFS models over the much faster
00Z NAM model with cold frontal passage from west to east across
IL during Saturday afternoon/evening. Best chances of showers and
thunderstorms will be during this time and SPC has 5% risk of
severe storms over much of IL Saturday afternoon and early
Saturday evening. With slower frontal movement have continued
warmer trends for Saturday highs ranging from mid 70s western IL
and around 80F in eastern IL.
Continued a chance of showers Sunday especially over eastern IL
with cooler highs in the lower 60s central IL and mid 60s se IL.
strong upper level trof to move into the region early next week
bringing the cooler weather.
LONG TERM...Monday through Wednesday night
Pleasant weather expected Monday through Wednesday as strong upper
level trof/low lifts out of the Midwest and getting some upper
level ridging into the MS valley by the middle of next week. This
should warm temperatures from mid to upper 60s Monday and into the
mid 70s Tuesday and mid to upper 70s Wed.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1105 AM CDT THU OCT 3 2013
.DISCUSSION...
336 AM CDT
I FEEL LIKE A KID COMING HOME FROM THEIR FIRST DAY OF SCHOOL WITH A
MILLION THINGS TO TELL THEIR PARENTS ABOUT...EXCEPT I`VE GOT ABOUT A
MILLION FORECAST THINGS TO TALK ABOUT THIS MORNING. HIGHLIGHTS
INCLUDE TEMPS AND THUNDERSTORM CHANCES THE NEXT FEW DAYS ALONG WITH
STRATUS/FOG POTENTIAL.
FIRST UP...PRECIP/TSTM CHANCES TODAY. GUIDANCE HAS BEEN REALLY OF
VERY LITTLE HELP THUS FAR TONIGHT AS CONVECTION HAS BEEN SPOTTY
OVER MOST OF IL/IN WHERE DAY AFTER DAY NOW MODELS HAVE HAD A
STRONG QPF SIGNAL LATE TONIGHT INTO THURSDAY MORNING. THE RAP/HRRR
ARE KEYING IN ON SHORTWAVE ENERGY OVER EASTERN KS TO PRODUCE A
CONVECTIVE COMPLEX MOVING INTO N IL THIS AFTERNOON...BUT THE
SHORTWAVE ENERGY OVER THE PLAINS SEEMS TO BE MORE FOCUSED WITH THE
MCV OVER SE NE THAT IS INCHING MORE SOUTHEASTWARD. ANOTHER
PRONOUNCED SHORTWAVE OVER WISCONSIN IS PUSHING EASTWARD AND LIKELY
TO ONLY PROVIDE A GLANCING BLOW OF LARGE SCALE ASCENT IN OUR CWA
THIS AFTERNOON. THE SURFACE WARM FRONT AND BETTER SFC FOCUS FOR
CONVECTION IS LIFTING NORTH INTO WISCONSIN AND SHOULD BE OUT OF
THE AREA BY AROUND SUNRISE...LEAVING VERY LITTLE TO HANG MY HAT ON
FORCING-WISE FOR CONVECTION THIS AFTERNOON. GIVEN THE PROGGED
MODERATE INSTABILITY WITH LITTLE INHIBITION AND WEAK ASCENT WITH
VARIOUS SUBTLE SHORTWAVES THINK THAT ISOLATED TO SCATTERED
SHOWERS/STORMS WILL DOT THE AREA THROUGH THE DAY...BUT HARD TO
ENVISION A SCENARIO WHERE STORMS BECOME WELL ORGANIZED AND COVERAGE
HIGH ENOUGH TO JUSTIFY REALLY BIG POPS TODAY.
OTHER HEADACHE TODAY WILL BE WITH STRATUS/CLOUD COVER AND SUBSEQUENT
EFFECT ON TEMPERATURES. MID-HIGH CLOUDS ARE MASKING THE LOW
STUFF...BUT IT APPEARS THAT STRATUS DECK IS BLOSSOMING AGAIN THIS
MORNING SOUTH OF THE WARM FRONT WHICH WILL NO DOUBT TAKE TIME TO
BURN OFF. WHERE POCKETS OF THE GREATEST HEATING/SUNSHINE OCCUR TODAY
HIGHS SHOULD REACH INTO THE LOW 80S WITH MID/UPPER 70S WHERE STRATUS
HANGS ON OR IS SLOWEST TO BURN OFF.
STRONG UPPER LEVEL JET WILL COME NOSING INTO THE PLAINS AND MID
MISSISSIPPI VALLEY TONIGHT WITH LEFT EXIT REGION OF THAT JET NOSING
INTO FAR NORTHERN ILLINOIS AND ESPECIALLY WISCONSIN TONIGHT. THE
WARM FRONT SHOULD BE NORTH OF THE STATE LINE...SO CONCEPTUALLY THAT
SHOULD PLACE THE HIGHEST CONVECTIVE CHANCES IN WISCONSIN WHERE
STRONGEST ISENTROPIC ASCENT WILL OCCUR COUPLED WITH STRONGER UPPER
LEVEL DIVERGENCE IN THE LEFT EXIT REGION OF THE JET. OUR NORTHERN
COUNTIES ARE CLOSE ENOUGH TO THIS SET UP TO WARRANT CHANCE POPS
TONIGHT BUT WOULD THINK THE MAIN SHOW WILL BE NORTH. CERTAINLY
PLAUSIBLE THAT STRATUS AND SOME FOG COULD RE-DEVELOP IN THE WARM
SECTOR TONIGHT AND SKY FORECAST IS LOW CONFIDENCE AS ANOTHER LOW OVC
DECK COULD BLOSSOM OVERNIGHT IN THE JUICY MID 60 DEWPOINT AIRMASS.
THIS LEADS INTO THE UNCERTAINTIES WITH FRIDAY`S FORECAST. ASSUMING
WE DON`T SPEND MOST OF FRIDAY MORNING TRYING TO BURN OFF A STRATUS
DECK...THEN THE POTENTIAL IS THERE FOR TEMPS TO REALLY GET OUT OF
HAND FRIDAY. MORNING LOWS IN THE MID TO UPPER 60S WILL PROVIDE A
NICE SPRING BOARD FOR TEMPS TO CLIMB INTO THE 80S...POSSIBLY
MID-UPPER 80S IF WE DON`T HAVE TO WASTE ANY OF OUR RAPIDLY
SHORTENING SUNLIGHT ON THE STRATUS. LIKE TUESDAY...MORE CLOUDS COULD
RESULT IN A SIZABLE FORECAST BUST. PRECIP-WISE...WE WILL BE WARM AND
UNSTABLE BUT BETTER FORCING SHOULD BE NORTH OF THE WARM FRONT IN
WISCONSIN AND WELL WEST OF THE CWA IN THE EASTERN PLAINS AND CORN
BELT WHERE A BIG SEVERE WEATHER EVENT COULD UNFOLD FRI AFTERNOON AND
EVENING. OBVIOUSLY OUR PRECIP THREAT ISNT ZERO...BUT BARRING ANY
UNFORESEEN MESOSCALE DEVELOPMENT THURSDAY NIGHT SHOULD BE VERY LOW
SYNOPTICALLY FRIDAY INTO FRIDAY EVENING.
ITS UNCLEAR HOW MUCH OF THE LEFTOVER`S OF IOWA`S POTENTIAL SEVERE
WEATHER EVENT WILL SURVIVE THROUGH THE NIGHT TO MAKE IT INTO OUR
AREA LATE AT NIGHT OR SATURDAY MORNING. GIVEN THE STORM SYSTEM WILL
BEGIN TO OCCLUDE AND FORCING NOT TREMENDOUS WOULD TEND TO THINK THAT
A SUBSTANTIAL WEAKENING IF NOT OUTRIGHT DISSIPATION OF THIS
CONVECTION COULD OCCUR BEFORE REACHING OUR CWA...BUT CERTAINLY
CHANCE POPS ARE WORTHY.
HUGE DIFFERENCES ARISE BETWEEN MOST OF THE GLOBAL MODELS AND THE
WRF-NAM AND SOME OF THE OTHER CONVECTIVE ALLOWING REGIONAL MODELS.
THE GLOBAL MODELS ARE GENERALLY ALL SLOWER WITH THE UPPER LOW AND
ASSOCIATED COLD FRONT MOVING THROUGH OUR CWA. THE SYSTEM WAS STILL
JUST OFFSHORE AT 00Z WHICH WOULD MAKE ME PUT A FEW MORE EGGS IN THE
BASKET OF THE GLOBAL MODELS...PLUS THESE BIGGER WESTERN SYSTEMS
FREQUENTLY END UP VERIFYING THE SLOWER END OF THE GUIDANCE ENVELOPE.
GIVEN THIS REASONING...HAVE FOLLOWED A GFS/ECMWF COMPROMISE WHICH
KEEPS OUR CWA IN THE WARM/HUMID SECTOR OF THE SYSTEM SATURDAY. THE
EC/GFS ARE A BIT SLOWER TO OCCLUDE THE STORM AND FORECAST A LITTLE
BETTER LOOKING OF A SHEAR PROFILE FOR SATURDAY THAN WHAT THEY SHOWED
YESTERDAY...BUT STILL LOOKS LIKE MODERATE SHEAR/WEAK-MODERATE
INSTABILITY SET-UP THAT DOESN`T EXACTLY SCREAM SEVERE WEATHER
POTENTIAL SATURDAY AFTERNOON. CERTAIN SOME THREAT OF DAMAGING WIND
COULD EXIST IF SQUALL LINE DEVELOPS...BUT UNLESS FORECASTED
SHEAR/INSTABILITY PROFILES IMPROVED MARKEDLY FOR SATURDAY OUR SEVERE
WEATHER THREAT LOOKS MARGINAL.
SUNDAY LOOKS MUCH MUCH COLDER WITH HIGHS POTENTIALLY HOLDING IN THE
50S...BUT UPPER LOW LOOKS TO GET CUT OFF FROM THE MAIN POLAR BRANCH
OF THE JET PRECLUDING ANY HUGE EARLY SEASON COLD SNAP. ONCE THE
CLOSED LOW WOBBLES EAST OF THE AREA TEMPS WILL QUICKLY MODERATE TO
AVERAGE AND LIKELY ABOVE AVERAGE LEVELS AGAIN NEXT WEEK. TIMING OF
THIS UPPER LOWS DEPARTURE AND SUBSEQUENT WARM UP WILL PROBABLY BE AN
ITEM UP FOR DEBATE AMONG THE MEDIUM RANGE MODELS THE NEXT FEW DAYS
AS CUT OFF LOWS LIKE THIS AREN`T TYPICALLY A STRONG SUIT OF THE
MODELS.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PERIOD OF -SHRA/VCTS THIS MORNING...EXITING BY THE 17Z TIME
FRAME.
* CONTINUED RAPID IMPROVEMENT WITH CEILINGS OVER THE NEXT 1-2
HOURS.
* CHANCES FOR ADDITIONAL THUNDERSTORMS AND LOW CEILINGS TONIGHT.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
A SURFACE WARM FRONT HAS MADE A MESS OF THINGS THIS MORNING AS IT
HAS LIFTED ACROSS NORTHERN ILLINOIS. THE RAPID INFLUX OF MOISTURE
IN ITS WAKE...LED TO THE RAPID DEVELOPMENT OF FOG AND VERY LOW
CIGS. THINGS WILL IMPROVE A BIT SHORTLY AFTER 12 UTC THIS MORNING
AS THE SURFACE WARM FRONT LIFTS NORTH OF THE AREA...AND TAKES THE
EXTREMELY LOW STUFF WITH IT. WITH THIS BEING SAID...CIGS WILL
LIKELY REMAIN IN THE 4-600 FOOT RANGE FOR SEVERAL HOURS YET THIS
MORNING...BEFORE ADDITIONAL IMPROVEMENT OCCURS. THIS COULD TAKE US
THROUGH THE 15 UTC HOUR WITH IFR CIGS REMAINING IN PLACE.
THERE IS ALSO A DECENT CLUSTER OF STORMS TO THE SOUTHWEST OF THE
AREA ACROSS CENTRAL AND WESTERN ILLINOIS. THIS ACTIVITY IS
ASSOCIATED WITH A MID LEVEL DISTURBANCE. THESE STORMS WILL MOVE
ACROSS THE TERMINALS...LIKELY BETWEEN 15 TO 17-18 UTC THIS
MORNING. BRIEF PERIODS OF HEAVY RAINFALL WILL ACCOMPANY THESE
STORMS. ONCE THE STORMS PASS...CIGS AND VSBYS SHOULD BEGIN TO
IMPROVE INTO THE AFTERNOON.
ADDITIONAL LOW CLOUDS AND AREAS OF FOG ARE AGAIN POSSIBLE TONIGHT
WITH THE AIRMASS REMAINING VERY MOIST.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE WITH -SHRA/VCTS TIMING AROUND THE TERMINALS THIS
MORNING.
* HIGH CONFIDENCE WITH CEILING/FOG TRENDS THIS MORNING.
* LOW-MEDIUM CONFIDENCE IN ADDITIONAL THUNDERSTORMS/FOG/LOW CIGS
TONIGHT.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR VIS POSSIBLE..OTHERWISE VFR.
SATURDAY...TSRA LIKELY. GUSTY SW WIND.
SUNDAY...CHC OF SHRA. GUSTY SW WIND
MONDAY-WEDNESDAY...VFR.
KJB
&&
.MARINE...
315 AM CDT
THE MAIN WEATHER CONCERNS OVER THE LAKE CONTINUE TO FOCUS ON THE
EVOLUTION OF A STORM SYSTEM EXPECTED TO MOVE ACROSS THE
UPPER MIDWEST AND THE UPPER GREAT LAKES THIS WEEKEND.
IT STILL APPEARS THAT A WARM FRONT WILL SLOWLY LIFT NORTHWARD ACROSS
LAKE MICHIGAN OVER THE NEXT COUPLE DAYS...LIKELY BECOMING NEARLY
STATIONARY FOR A PERIOD SOMEWHERE ACROSS THE CENTRAL PORTION OF THE
LAKE. THE SURFACE LOW ITSELF WILL MATURE SATURDAY ACROSS THE UPPER
MISSISSIPPI VALLEY. THIS PROCESS WILL ALLOW EAST-NORTHEASTERLY WINDS
TO INCREASE ACROSS NORTHERN LAKE MICHIGAN TONIGHT AND ON FRIDAY...TO
THE NORTH OF THE SURFACE WARM FRONT. MEANWHILE...SOUTH OF THE
FRONT...SOUTHERLY FLOW WILL SETT UP. WITH TIME...THE LOW WILL LIFT
EAST-NORTHEASTWARD ACROSS THE UPPER GREAT LAKES REGION INTO SUNDAY.
ONCE THIS OCCURS...A DECENT COLD FRONT SHOULD BE SWEPT ACROSS THE
LAKE BY SUNDAY. A DECENT SHOT OF COLD AIR IN THE WAKE OF THIS FRONT
SHOULD SUPPORT SOME 20 TO 25 KT WEST-SOUTHWESTERLY WINDS FOR A
PERIOD SATURDAY NIGHT AND SUNDAY...WITH GUSTS TO 30 KT ALSO
POSSIBLE.
THE OTHER CONCERN OVER THE WEEKEND IS THE THREAT FOR WATER SPOUTS.
FOLLOWING THE COLD FRONTAL PASSAGE...IT APPEARS THAT SOME COLD AIR
WILL MOVE OVER THE LAKE SUNDAY AND SUNDAY NIGHT AS THE UPPER LOW
MOVES OVERHEAD. GIVEN THE CURRENT LAKE TEMPS...THIS COLD AIR MASS
COULD SETUP FAVORABLE CONDITIONS FOR WATER SPOUTS...PARTICULARLY LATE
SUNDAY AND SUNDAY NIGHT. I HAVE NOT INCLUDED THE MENTION OF THIS IN
THE LATEST FORECAST...MAINLY DUE TO UNCERTAINTIES ON THE EXACT TRACK
OF THE SYSTEM AND THE AMOUNT OF COLD AIR INTO SUNDAY NIGHT...BUT
LATER FORECASTS MAY NEED TO ADD THE MENTION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
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Area Forecast Discussion
National Weather Service Lincoln IL
1024 AM CDT Thu Oct 3 2013
.DISCUSSION...
ISSUED 1024 AM CDT Thu Oct 3 2013
One short-wave trough is currently rippling northward into
northern Illinois, while a second wave is noted on water vapor
imagery further southwest over western Missouri. Showers/storms
associated with the first feature have primarily lifted north of
the KILX CWA...leaving behind partly sunny and dry conditions for
the time being. Meanwhile, the second wave is triggering scattered
convection across northern Missouri/southern Iowa. This activity
will track E/NE into portions of central Illinois this afternoon
and evening. Latest runs of both the NAM and HRRR suggest
convection will spread across mainly locations along and north of
a Jacksonville to Rantoul line. Based on model data and current
radar/satellite trends, have focused highest POPs across the
northern CWA this afternoon/evening...with only slight chances
featured south of the I-72 corridor. Zone update has already been
issued.
Barnes
&&
.AVIATION...
ISSUED 655 AM CDT Thu Oct 3 2013
Scattered showers and a few thunderstorms are expected over the
next few hours as an upper level disturbance moves across central
Illinois. There will be an associated risk of MVFR or IFR
conditions. Later this morning into this afternoon, a return to VFR
conditions is anticipated as the disturbance departs. However, the
break may be short lived as another disturbance is expected to
move through in the late afternoon and early evening. This
disturbance will produce an additional risk of shower/storms.
Light winds, high dew point air, recent rains, and mostly clear
skies will likely set the stage for some stratus/fog development
again by late tonight. Have included a mention of MVFR fog late
tonight along with scattered stratus. More detail will need to be
added to this portion of the forecast as confidence grows in the
expected extent of stratus/fog.
Bak
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT Thu Oct 3 2013
SHORT TERM...Today through Sunday night
Some fog and stratus clouds below 1k ft over parts of central IL
early this morning, though not nearly as widespread as past few
days due to a bit stronger south winds and more mid level clouds
around. Patchy fog should lift by 15Z/10 am this morning. Short
range models continue to develop showers and a few thunderstorms
across central IL during this morning due to short waves lifting
up across IL and then diminish this afternoon as short wave exits
east of IL by sunset. Radar mosaic recently showing some showers
appearing west of I-57 and lifting nne. Will carry scattered
showers this morning and be more likely from I-74 north today.
Have highs in the low to mid 80s, but guidance has been too warm
past few days especially over cloudier areas of eastern/se IL,
so kept these areas a few degrees cooler today.
Somewhat of a lull tonight and Friday with just isolated
convection around as best forcing is north of MN/WI/MI and also
have a weak disturbance over the mid MS and lower OH valleys where
isolated convection possible Friday se of I-70. Lows tonight
mostly in the mid 60s. Highs Friday in the mid to upper 80s with
breezy ssw winds.
Favored the slower 00Z ECMWF and GFS models over the much faster
00Z NAM model with cold frontal passage from west to east across
IL during Saturday afternoon/evening. Best chances of showers and
thunderstorms will be during this time and SPC has 5% risk of
severe storms over much of IL Saturday afternoon and early
Saturday evening. With slower frontal movement have continued
warmer trends for Saturday highs ranging from mid 70s western IL
and around 80F in eastern IL.
Continued a chance of showers Sunday especially over eastern IL
with cooler highs in the lower 60s central IL and mid 60s se IL.
strong upper level trof to move into the region early next week
bringing the cooler weather.
LONG TERM...Monday through Wednesday night
Pleasant weather expected Monday through Wednesday as strong upper
level trof/low lifts out of the Midwest and getting some upper
level ridging into the MS valley by the middle of next week. This
should warm temperatures from mid to upper 60s Monday and into the
mid 70s Tuesday and mid to upper 70s Wed.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
316 AM CDT THU OCT 3 2013
.DISCUSSION...
903 PM CDT
FOR EVENING UPDATE...
HAVE LOWERED POPS OVERALL THROUGH 09Z TONIGHT BASED ON RADAR AND
HIGH-RES SHORT TERM GUIDANCE TRENDS. HAVE ALSO RAISED MINS A
LITTLE OVERNIGHT WITH WARM FRONT LIFTING ACROSS AREA AND FAIRLY
EXTENSIVE MID-HIGH CLOUD COVER ESPECIALLY SOUTH/EAST.
WARM FRONT WAS ANALYZED FROM ROUGHLY NEAR STERLING IL EAST-
SOUTHEAST INTO SOUTHERN WILL COUNTY AND JUST NORTH OF THE KANKAKEE
RIVER VALLEY IN NORTHWEST INDIANA AT 01Z. A FEW ISOLATED SHOWERS
HAD DEVELOPED THIS AFTERNOON ALONG THE EASTERN PORTION OF THE WARM
FRONT...AS WELL AS A FEW FARTHER SOUTH INTO EAST CENTRAL IL ALONG
A DIFFERENTIAL HEATING BOUNDARY LEFT OVER FROM THE NORTH SIDE OF
THE STRATUS DECK WHICH ERODED ACROSS CENTRAL IL EARLIER TODAY.
HOWEVER SUNSET...AND THE LOSS OF DIURNAL INSTABILITY IN THE
BOUNDARY LAYER HAS ALLOWED THESE ISOLATED SHOWERS TO DISSIPATE AT
THIS TIME. LOW LEVEL FRONTAL ZONE REMAINS QUITE SHARP PARTICULARLY
AS INDICATED BY 925 MB ANALYSIS FROM 00Z...AND MAY CONTINUE TO
PRESENT A MECHANISM FOR PRODUCING ISOLATED SHOWERS ALONG AND NORTH
OF THE FRONT THIS EVENING. TRENDS FROM HIGH-RES SHORT RANGE
GUIDANCE FROM WRF- NMM...WRF-ARW AND HRRR SEEM TO INDICATE A LULL
THROUGH THE REMAINDER OF THE EVENING AND EARLY OVERNIGHT HOURS
HOWEVER...INDICATING PERHAPS A LITTLE BETTER POTENTIAL FOR SHOWERS
IN THE 09-12Z TIME FRAME OF EARLY THURSDAY MORNING. THIS APPEARS
TO BE LINKED TO APPROACH OF SHORT WAVE TROUGH MID-MISSOURI VALLEY
THIS EVENING...AND SOME INCREASE IN MOISTURE TRANSPORT FROM POOL
OF HIGHER 925-850 MB DEW POINT AIR NOTED UPSTREAM. ASIDE FROM
FRONTAL ZONE HOWEVER...FORCING APPEARS FAIRLY SUBTLE HOWEVER AND
SUSPECT POPS COULD EVEN BE OVERDONE INTO THURSDAY MORNING. WITH
SOME UNCERTAINTY WILL LIMIT CHANGES TO JUST PUSHING BACK TIMING OF
BETTER PRECIP POTENTIAL TO PRE-DAWN HOURS AS INDICATED.
OTHERWISE...ONLY MINOR CHANGES TO SKY COVER AND TEMPS AS INDICATED
PREVIOUSLY.
RATZER
//PREV DISCUSSION...
329 PM CDT
MAIN FORECAST CONCERN WILL BE WITH TEMPERATURES AND PCPN CHANCES FOR
THE NEXT FEW DAYS.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING...CONDITIONS
WILL BE QUIET...BUT WILL NEED TO CLOSELY MONITOR THE RETURN
NORTHWARD OF THE FRONTAL BOUNDARY THAT PUSHED SOUTH THROUGH THE AREA
LAST NIGHT. LATEST SATELLITE IMAGERY SHOWS THAT THE STRATUS DECK
ALONG AND SOUTH OF THE BOUNDARY...WHICH EXTENDS GENERALLY ALONG THE
ILLINOIS/KANKAKEE RIVERS...HAS ERODED AND TEMPERATURES ACROSS THE
ENTIRE AREA HAVE CLIMBED INTO THE MIDDLE TO UPPER 70S...WITH SOME 80
DEGREE READING LIKELY BEFORE SUNSET. THE PRIMARY CONTRAST ALONG THE
BOUNDARY WILL BE A WIND SHIFT AND A STRONG DEWPOINT CONTRAST RATHER
THAN A TEMPERATURE CONTRAST. AT ISSUANCE TIME...DEWPOINTS SOUTH OF
THE BOUNDARY ARE IN THE MIDDLE TO UPPER 60S...WHILE NORTH OF THE
FRONT...DEWPOINTS ARE ONLY IN THE LOWER TO MIDDLE 40S. THE BOUNDARY
IS EXPECTED TO SURGE NORTH THROUGH THE EVENING...BRINGING THE HIGH
MOISTURE CONTENT AIR BACK ACROSS THE THE ENTIRE REGION. THIS SURGE
OF MOISTURE RIDING ON THE NOSE OF STRENGTHENING LOW LEVEL LOW LEVEL
FLOW...INCREASING WARM ADVECTION AND ISENTROPIC LIFT WILL BRING AN
INCREASING CHANCE OF SHOWERS AND A FEW THUNDERSTORMS TO THE
REGION...WITH AN INCREASING POP TREND BOTH TEMPORALLY AND SPATIALLY
THROUGH THE EVENING AND OVERNIGHT.
THE LOCAL AREA WILL REMAIN SOLIDLY IN WARM SECTOR AIR WITH MAX
TEMPERATURES OVER THE NEXT COUPLE DAYS INCREASING A FEW DEGREES EACH
DAY THROUGH FRIDAY AS UPPER RIDGING BUILDS IN ADVANCE OF A DEEP
CLOSED LOW WHICH IS ONLY NOW MOVING INTO THE PACIFIC NORTHWEST. FOR
THURSDAY...EXPECTING TEMPERATURES TO RANGE FROM THE UPPER 70S TO
LOWER 80S. MODEST SOUTHERLY-SWLY FLOW THROUGH THE LOWER LEVELS...DO
NOT EXPECT A LAKE BREEZE TO DEVELOP AND THE WARMER AIR SHOULD SPREAD
RIGHT UP TO THE LAKEFRONT...AND EVEN DOWNTOWN CHICAGO SHOULD SEE
TEMPERATURES PEG AROUND 80F. BY FRIDAY...THE WARM FRONT SHOULD
BECOME QUASI-STATIONARY ACROSS CENTRAL WISCONSIN AND MIDWAY UP LAKE
MICHIGAN AS A SFC TROUGHING DEVELOPS OVER THE CNTRL PLAINS AS THE
UPPER LOW SWINGS THROUGH THE CNTRL ROCKIES AND EJECTS OUT OVER THE
CNTRL PLAINS. AS THE UPPER LEVEL SYSTEM IS ONLY NOW BEGINNING TO BE
SAMPLED BY REAL DATA...THE MODEL TRENDS AND CHANGING A BIT FROM
RECENT RUNS. THE MAIN TREND HAS BEEN TO SLOW THE PROGRESSION OF THE
UPPER LEVEL SYSTEM AND THE ASSOCIATED COLD FRONT...WITH THE FRONT
ONLY REACHING THE MIDDLE MISSISSIPPI VALLEY BY SATURDAY. SO...IN
THE MEAN TIME...THE WARMING TREND SHOULD CONTINUE FOR AN ADDITIONAL
DAY. THIS ADDITIONAL PERIOD OF STRONG WARM/MOIST ADVECTION ACROSS
THE REGION...EXPECT NOW THAT TEMPS ON FRIDAY SHOULD RANGE FROM THE
LOWER 80S ALONG THE WISCONSIN...INCREASING TO THE MIDDLE TO UPPER
80S SOUTH OF THE I-80 CORRIDOR. WITH SFC DEWPOINTS IN THE MIDDLE TO
UPPER 60S FOR THURSDAY AND FRIDAY...CONDITIONS WILL CERTAINLY BE
UNSEASONABLY WARM AND HUMID.
UNDER THE PERSISTENT WARM/MOIST ADVECTION...PCPN CHANCES WILL BE
HIGH WITH POPS IN THE LIKELY TO CATEGORICAL RANGES THROUGH MUCH OF
THE TIME FROM LATE TONIGHT THROUGH FRIDAY NIGHT...STRICTLY FROM THE
WARM ADVECTIVE PATTERN. BY SATURDAY...THE APPROACHING COLD FRONT
WILL BECOME THE MAJOR WEATHER PLAYER...KEEPING ENHANCED PCPN CHANCES
OVER THE AREA THROUGH MUCH OF THE WEEKEND. THE MAIN CHANCE TO THE
GOING FORECAST HAS BEEN TO SLOW DOWN THE PROGRESSION OF THE UPPER
LOW AND ASSOCIATED SFC COLD FRONT. THE LATEST GUIDANCE...IN
PARTICULAR THE GFS/ECMWF IS TRENDING AROUND 12 HOURS SLOWER THAN
PREVIOUS RUNS...WITH THE NAM A FAST OUTLIER. GENERALLY...PREFER THE
SLOWER SOLUTIONS AS THE UPPER LOW DIGS SOUTHWARD AND TAKES SOME TIME
DEEPENING OVER THE SOUTH HIGH PLAINS BEFORE KICKING OUT TO THE
NORTHEAST. TOTAL PCPN ACROSS THE AREA FROM LATE TONIGHT THROUGH
SATURDAY NIGHT SHOULD RANGE FROM 0.5-0.75 INCHES OVER THE SERN
PORTIONS OF THE CWA...TO ALMOST 1.5 INCHES OVER THE ROCKFORD AREA.
BY THE TIME THAT THE SYSTEM REACHES THE UPPER MISSISSIPPI VALLEY ON
SATURDAY...FORECAST PWATS ARE EXPECTED TO INCREASE TO 1.5 - 1.75
INCHES. FOR EARLY OCTOBER...THIS IS IN THE 99TH PERCENTILE PER THE
KDVN PWAT CLIMATOLOGY. GIVEN THIS EXTREME LEVEL OF DEEP LAYER
MOISTURE SETTING UP FOR THE NEXT FEW DAYS...THERE IS A CHANCE THAT
THE QPF IN THE CURRENT FORECAST MAY BE A BIT LOW AND THERE IS A
SIGNIFICANT CHANCE THAT MEASURED PCPN COULD BE HIGHER THAT CURRENTLY
INDICATED. CERTAINLY...THERE WILL LIKELY BE LOCALLY HIGHER AMOUNTS
AROUND STRONGER SHOWERS OR THUNDERSTORMS.
FOR THE EXTENDED FORECAST PERIOD...FROM SUNDAY THROUGH
WEDNESDAY...WEATHER SHOULD BE SIGNIFICANTLY QUIETER FOLLOWING THE
COLD FRONT PASSAGE. COOLER/DRIER AIR SHOULD FILTER IN BEHIND THE
EXITING FRONT AND HIGH PRESSURE BUILDS ACROSS THE NORTHERN PLAINS
AND INTO THE MIDDLE AND UPPER MISSISSIPPI VALLEY. FOR THE EXTENDED
FORECAST PERIOD...EXPECT TEMPERATURES TO BE THE LOWEST ON SUNDAY
WITH HIGHS IN THE UPPER 50S TO LOWER 60S. TEMPERATURES SHOULD THEN
MODERATE BY MIDWEEK...WITH HIGHS IN THE LOWER TO MIDDLE 70S BY
WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* INCREASING CHANCES FOR -SHRA/-TSRA THURSDAY MORNING.
* LOW CEILINGS AND FOG DEVELOPING OVERHEAD THROUGH THE
MORNING...WITH IFR CEILINGS LIKELY AND A POSSIBILITY FOR LIFR
CEILINGS.
* CHANCES FOR MORE THUNDERSTORMS THURSDAY NIGHT...MAINLY NORTH.
KJB
//DISCUSSION...UPDATED 06Z...
A SURFACE WARM FRONT IS LOCATED JUST TO THE SOUTH OF THE TERMINALS
EARLY THIS MORNING. TO THE SOUTH OF THIS FRONT...THE ATMOSPHERE IS
QUITE MOIST...WITH DEW POINTS IN THE MID 60S. THIS FRONT WILL LIFT
NORTHWARD OVER THE TERMINALS OVER THE NEXT FEW HOURS...ALLOWING THIS
BETTER MOISTURE TO MOVE BACK ACROSS NORTHERN ILLINOIS. THIS LOOKS TO
SET THE STAGE FOR ANOTHER MORNING OF LOW CIGS AND LOW VIS ACROSS THE
AREA...POTENTIALLY AS LOW AS 500-900 FEET AGL. THE CURRENT TIMING OF
09 UTC STILL APPEARS GOOD. HOWEVER...SOME FEW AND SCT CLOUDS HAVE
BEEN DEVELOPING AROUND 1500 AGL...SO THE CONDITIONS ARE ARE SETTING
UP FOR LOW CIGS ALREADY. GIVEN THAT THE DEW POINTS WILL INCREASE A
GOOD 7 TO 10 DEGREES AT THE TERMINALS OVERNIGHT...I EXPECT THERE
WILL ALSO BE AT LEAST SOME MVFR VIS IN THE 3 TO 5 MILE RANGE. THIS
ACTIVITY WILL LIKELY BE SLOW TO IMPROVE DURING THE MORNING...WITH NO
BIG IMPROVEMENTS UNTIL AFTER 17-18 UTC.
THE OTHER CONCERN IS THE CHANCES AND TIMING OF ANY CONVECTIVE
ACTIVITY OVER THE NEXT 24 TO 30 HOURS. REGIONAL RADAR IMAGERY
INDICATES SOME ISOLATED ACTIVITY OUT WEST NEAR THE MISSISSIPPI. SOME
ADDITIONAL WIDELY SCATTERED ACTIVITY WILL BE POSSIBLE OVER THE NEXT
FEW HOURS ACROSS PORTIONS OF WESTERN ILLINOIS. HOWEVER...IT APPEARS
THAT THE TERMINALS WILL REMAIN DRY THROUGH THE REST OF THE OVERNIGHT
PERIOD. IT STILL APPEARS THERE WILL BE A CHANCE OF
SHOWER/THUNDERSTORM ACTIVITY DURING THE MID TO LATE MORNING HOURS AS
A MID LEVEL DISTURBANCE APPROACHES THE AREA. I HAVE DECIDED TO
CONTINUE WITH THE PROB30 MENTION...AS OVERALL CONFIDENCE IN THUNDER
REMAINS LOW TO MEDIUM.
ADDITIONAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE AGAIN TONIGHT.
HOWEVER...IT APPEARS AT THIS TIME THAT THE MAIN AXIS FOR STORMS WILL
SHIFT NORTHWARD ACROSS SOUTHERN WISCONSIN.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW-MEDIUM CONFIDENCE WITH -SHRA/TSRA TIMING.
* HIGH CONFIDENCE WITH MVFR CEILINGS...MEDIUM-HIGH CONFIDENCE
WITH IFR CEILINGS...AND LOW-MEDIUM CONFIDENCE WITH LIFR
CEILINGS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC OF TSRA.
FRIDAY NIGHT...SHRA..CHC OF TSRA.
SATURDAY...CHC OF TSRA. SHRA MAINLY IN THE EVENING. GUSTY SW WIND.
SUNDAY...CHC OF SHRA.
MONDAY-TUESDAY...VFR.
ZEBIC
&&
.MARINE...
315 AM CDT
THE MAIN WEATHER CONCERNS OVER THE LAKE CONTINUE TO FOCUS ON THE
EVOLUTION OF A STORM SYSTEM EXPECTED TO MOVE ACROSS THE
UPPER MIDWEST AND THE UPPER GREAT LAKES THIS WEEKEND.
IT STILL APPEARS THAT A WARM FRONT WILL SLOWLY LIFT NORTHWARD ACROSS
LAKE MICHIGAN OVER THE NEXT COUPLE DAYS...LIKELY BECOMING NEARLY
STATIONARY FOR A PERIOD SOMEWHERE ACROSS THE CENTRAL PORTION OF THE
LAKE. THE SURFACE LOW ITSELF WILL MATURE SATURDAY ACROSS THE UPPER
MISSISSIPPI VALLEY. THIS PROCESS WILL ALLOW EAST-NORTHEASTERLY WINDS
TO INCREASE ACROSS NORTHERN LAKE MICHIGAN TONIGHT AND ON FRIDAY...TO
THE NORTH OF THE SURFACE WARM FRONT. MEANWHILE...SOUTH OF THE
FRONT...SOUTHERLY FLOW WILL SETT UP. WITH TIME...THE LOW WILL LIFT
EAST-NORTHEASTWARD ACROSS THE UPPER GREAT LAKES REGION INTO SUNDAY.
ONCE THIS OCCURS...A DECENT COLD FRONT SHOULD BE SWEPT ACROSS THE
LAKE BY SUNDAY. A DECENT SHOT OF COLD AIR IN THE WAKE OF THIS FRONT
SHOULD SUPPORT SOME 20 TO 25 KT WEST-SOUTHWESTERLY WINDS FOR A
PERIOD SATURDAY NIGHT AND SUNDAY...WITH GUSTS TO 30 KT ALSO
POSSIBLE.
THE OTHER CONCERN OVER THE WEEKEND IS THE THREAT FOR WATER SPOUTS.
FOLLOWING THE COLD FRONTAL PASSAGE...IT APPEARS THAT SOME COLD AIR
WILL MOVE OVER THE LAKE SUNDAY AND SUNDAY NIGHT AS THE UPPER LOW
MOVES OVERHEAD. GIVEN THE CURRENT LAKE TEMPS...THIS COLD AIR MASS
COULD SETUP FAVORABLE CONDITIONS FOR WATER SPOUTS...PARTICULARLY LATE
SUNDAY AND SUNDAY NIGHT. I HAVE NOT INCLUDED THE MENTION OF THIS IN
THE LATEST FORECAST...MAINLY DUE TO UNCERTAINTIES ON THE EXACT TRACK
OF THE SYSTEM AND THE AMOUNT OF COLD AIR INTO SUNDAY NIGHT...BUT
LATER FORECASTS MAY NEED TO ADD THE MENTION.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1257 AM CDT THU OCT 3 2013
.DISCUSSION...
903 PM CDT
FOR EVENING UPDATE...
HAVE LOWERED POPS OVERALL THROUGH 09Z TONIGHT BASED ON RADAR AND
HIGH-RES SHORT TERM GUIDANCE TRENDS. HAVE ALSO RAISED MINS A
LITTLE OVERNIGHT WITH WARM FRONT LIFTING ACROSS AREA AND FAIRLY
EXTENSIVE MID-HIGH CLOUD COVER ESPECIALLY SOUTH/EAST.
WARM FRONT WAS ANALYZED FROM ROUGHLY NEAR STERLING IL EAST-
SOUTHEAST INTO SOUTHERN WILL COUNTY AND JUST NORTH OF THE KANKAKEE
RIVER VALLEY IN NORTHWEST INDIANA AT 01Z. A FEW ISOLATED SHOWERS
HAD DEVELOPED THIS AFTERNOON ALONG THE EASTERN PORTION OF THE WARM
FRONT...AS WELL AS A FEW FARTHER SOUTH INTO EAST CENTRAL IL ALONG
A DIFFERENTIAL HEATING BOUNDARY LEFT OVER FROM THE NORTH SIDE OF
THE STRATUS DECK WHICH ERODED ACROSS CENTRAL IL EARLIER TODAY.
HOWEVER SUNSET...AND THE LOSS OF DIURNAL INSTABILITY IN THE
BOUNDARY LAYER HAS ALLOWED THESE ISOLATED SHOWERS TO DISSIPATE AT
THIS TIME. LOW LEVEL FRONTAL ZONE REMAINS QUITE SHARP PARTICULARLY
AS INDICATED BY 925 MB ANALYSIS FROM 00Z...AND MAY CONTINUE TO
PRESENT A MECHANISM FOR PRODUCING ISOLATED SHOWERS ALONG AND NORTH
OF THE FRONT THIS EVENING. TRENDS FROM HIGH-RES SHORT RANGE
GUIDANCE FROM WRF- NMM...WRF-ARW AND HRRR SEEM TO INDICATE A LULL
THROUGH THE REMAINDER OF THE EVENING AND EARLY OVERNIGHT HOURS
HOWEVER...INDICATING PERHAPS A LITTLE BETTER POTENTIAL FOR SHOWERS
IN THE 09-12Z TIME FRAME OF EARLY THURSDAY MORNING. THIS APPEARS
TO BE LINKED TO APPROACH OF SHORT WAVE TROUGH MID-MISSOURI VALLEY
THIS EVENING...AND SOME INCREASE IN MOISTURE TRANSPORT FROM POOL
OF HIGHER 925-850 MB DEW POINT AIR NOTED UPSTREAM. ASIDE FROM
FRONTAL ZONE HOWEVER...FORCING APPEARS FAIRLY SUBTLE HOWEVER AND
SUSPECT POPS COULD EVEN BE OVERDONE INTO THURSDAY MORNING. WITH
SOME UNCERTAINTY WILL LIMIT CHANGES TO JUST PUSHING BACK TIMING OF
BETTER PRECIP POTENTIAL TO PRE-DAWN HOURS AS INDICATED.
OTHERWISE...ONLY MINOR CHANGES TO SKY COVER AND TEMPS AS INDICATED
PREVIOUSLY.
RATZER
//PREV DISCUSSION...
329 PM CDT
MAIN FORECAST CONCERN WILL BE WITH TEMPERATURES AND PCPN CHANCES FOR
THE NEXT FEW DAYS.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING...CONDITIONS
WILL BE QUIET...BUT WILL NEED TO CLOSELY MONITOR THE RETURN
NORTHWARD OF THE FRONTAL BOUNDARY THAT PUSHED SOUTH THROUGH THE AREA
LAST NIGHT. LATEST SATELLITE IMAGERY SHOWS THAT THE STRATUS DECK
ALONG AND SOUTH OF THE BOUNDARY...WHICH EXTENDS GENERALLY ALONG THE
ILLINOIS/KANKAKEE RIVERS...HAS ERODED AND TEMPERATURES ACROSS THE
ENTIRE AREA HAVE CLIMBED INTO THE MIDDLE TO UPPER 70S...WITH SOME 80
DEGREE READING LIKELY BEFORE SUNSET. THE PRIMARY CONTRAST ALONG THE
BOUNDARY WILL BE A WIND SHIFT AND A STRONG DEWPOINT CONTRAST RATHER
THAN A TEMPERATURE CONTRAST. AT ISSUANCE TIME...DEWPOINTS SOUTH OF
THE BOUNDARY ARE IN THE MIDDLE TO UPPER 60S...WHILE NORTH OF THE
FRONT...DEWPOINTS ARE ONLY IN THE LOWER TO MIDDLE 40S. THE BOUNDARY
IS EXPECTED TO SURGE NORTH THROUGH THE EVENING...BRINGING THE HIGH
MOISTURE CONTENT AIR BACK ACROSS THE THE ENTIRE REGION. THIS SURGE
OF MOISTURE RIDING ON THE NOSE OF STRENGTHENING LOW LEVEL LOW LEVEL
FLOW...INCREASING WARM ADVECTION AND ISENTROPIC LIFT WILL BRING AN
INCREASING CHANCE OF SHOWERS AND A FEW THUNDERSTORMS TO THE
REGION...WITH AN INCREASING POP TREND BOTH TEMPORALLY AND SPATIALLY
THROUGH THE EVENING AND OVERNIGHT.
THE LOCAL AREA WILL REMAIN SOLIDLY IN WARM SECTOR AIR WITH MAX
TEMPERATURES OVER THE NEXT COUPLE DAYS INCREASING A FEW DEGREES EACH
DAY THROUGH FRIDAY AS UPPER RIDGING BUILDS IN ADVANCE OF A DEEP
CLOSED LOW WHICH IS ONLY NOW MOVING INTO THE PACIFIC NORTHWEST. FOR
THURSDAY...EXPECTING TEMPERATURES TO RANGE FROM THE UPPER 70S TO
LOWER 80S. MODEST SOUTHERLY-SWLY FLOW THROUGH THE LOWER LEVELS...DO
NOT EXPECT A LAKE BREEZE TO DEVELOP AND THE WARMER AIR SHOULD SPREAD
RIGHT UP TO THE LAKEFRONT...AND EVEN DOWNTOWN CHICAGO SHOULD SEE
TEMPERATURES PEG AROUND 80F. BY FRIDAY...THE WARM FRONT SHOULD
BECOME QUASI-STATIONARY ACROSS CENTRAL WISCONSIN AND MIDWAY UP LAKE
MICHIGAN AS A SFC TROUGHING DEVELOPS OVER THE CNTRL PLAINS AS THE
UPPER LOW SWINGS THROUGH THE CNTRL ROCKIES AND EJECTS OUT OVER THE
CNTRL PLAINS. AS THE UPPER LEVEL SYSTEM IS ONLY NOW BEGINNING TO BE
SAMPLED BY REAL DATA...THE MODEL TRENDS AND CHANGING A BIT FROM
RECENT RUNS. THE MAIN TREND HAS BEEN TO SLOW THE PROGRESSION OF THE
UPPER LEVEL SYSTEM AND THE ASSOCIATED COLD FRONT...WITH THE FRONT
ONLY REACHING THE MIDDLE MISSISSIPPI VALLEY BY SATURDAY. SO...IN
THE MEAN TIME...THE WARMING TREND SHOULD CONTINUE FOR AN ADDITIONAL
DAY. THIS ADDITIONAL PERIOD OF STRONG WARM/MOIST ADVECTION ACROSS
THE REGION...EXPECT NOW THAT TEMPS ON FRIDAY SHOULD RANGE FROM THE
LOWER 80S ALONG THE WISCONSIN...INCREASING TO THE MIDDLE TO UPPER
80S SOUTH OF THE I-80 CORRIDOR. WITH SFC DEWPOINTS IN THE MIDDLE TO
UPPER 60S FOR THURSDAY AND FRIDAY...CONDITIONS WILL CERTAINLY BE
UNSEASONABLY WARM AND HUMID.
UNDER THE PERSISTENT WARM/MOIST ADVECTION...PCPN CHANCES WILL BE
HIGH WITH POPS IN THE LIKELY TO CATEGORICAL RANGES THROUGH MUCH OF
THE TIME FROM LATE TONIGHT THROUGH FRIDAY NIGHT...STRICTLY FROM THE
WARM ADVECTIVE PATTERN. BY SATURDAY...THE APPROACHING COLD FRONT
WILL BECOME THE MAJOR WEATHER PLAYER...KEEPING ENHANCED PCPN CHANCES
OVER THE AREA THROUGH MUCH OF THE WEEKEND. THE MAIN CHANCE TO THE
GOING FORECAST HAS BEEN TO SLOW DOWN THE PROGRESSION OF THE UPPER
LOW AND ASSOCIATED SFC COLD FRONT. THE LATEST GUIDANCE...IN
PARTICULAR THE GFS/ECMWF IS TRENDING AROUND 12 HOURS SLOWER THAN
PREVIOUS RUNS...WITH THE NAM A FAST OUTLIER. GENERALLY...PREFER THE
SLOWER SOLUTIONS AS THE UPPER LOW DIGS SOUTHWARD AND TAKES SOME TIME
DEEPENING OVER THE SOUTH HIGH PLAINS BEFORE KICKING OUT TO THE
NORTHEAST. TOTAL PCPN ACROSS THE AREA FROM LATE TONIGHT THROUGH
SATURDAY NIGHT SHOULD RANGE FROM 0.5-0.75 INCHES OVER THE SERN
PORTIONS OF THE CWA...TO ALMOST 1.5 INCHES OVER THE ROCKFORD AREA.
BY THE TIME THAT THE SYSTEM REACHES THE UPPER MISSISSIPPI VALLEY ON
SATURDAY...FORECAST PWATS ARE EXPECTED TO INCREASE TO 1.5 - 1.75
INCHES. FOR EARLY OCTOBER...THIS IS IN THE 99TH PERCENTILE PER THE
KDVN PWAT CLIMATOLOGY. GIVEN THIS EXTREME LEVEL OF DEEP LAYER
MOISTURE SETTING UP FOR THE NEXT FEW DAYS...THERE IS A CHANCE THAT
THE QPF IN THE CURRENT FORECAST MAY BE A BIT LOW AND THERE IS A
SIGNIFICANT CHANCE THAT MEASURED PCPN COULD BE HIGHER THAT CURRENTLY
INDICATED. CERTAINLY...THERE WILL LIKELY BE LOCALLY HIGHER AMOUNTS
AROUND STRONGER SHOWERS OR THUNDERSTORMS.
FOR THE EXTENDED FORECAST PERIOD...FROM SUNDAY THROUGH
WEDNESDAY...WEATHER SHOULD BE SIGNIFICANTLY QUIETER FOLLOWING THE
COLD FRONT PASSAGE. COOLER/DRIER AIR SHOULD FILTER IN BEHIND THE
EXITING FRONT AND HIGH PRESSURE BUILDS ACROSS THE NORTHERN PLAINS
AND INTO THE MIDDLE AND UPPER MISSISSIPPI VALLEY. FOR THE EXTENDED
FORECAST PERIOD...EXPECT TEMPERATURES TO BE THE LOWEST ON SUNDAY
WITH HIGHS IN THE UPPER 50S TO LOWER 60S. TEMPERATURES SHOULD THEN
MODERATE BY MIDWEEK...WITH HIGHS IN THE LOWER TO MIDDLE 70S BY
WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* INCREASING CHANCES FOR -SHRA/-TSRA THURSDAY MORNING.
* LOW CEILINGS AND FOG DEVELOPING OVERHEAD THROUGH THE
MORNING...WITH IFR CEILINGS LIKELY AND A POSSIBILITY FOR LIFR
CEILINGS.
* CHANCES FOR MORE THUNDERSTORMS THURSDAY NIGHT...MAINLY NORTH.
KJB
//DISCUSSION...UPDATED 06Z...
A SURFACE WARM FRONT IS LOCATED JUST TO THE SOUTH OF THE TERMINALS
EARLY THIS MORNING. TO THE SOUTH OF THIS FRONT...THE ATMOSPHERE IS
QUITE MOIST...WITH DEW POINTS IN THE MID 60S. THIS FRONT WILL LIFT
NORTHWARD OVER THE TERMINALS OVER THE NEXT FEW HOURS...ALLOWING THIS
BETTER MOISTURE TO MOVE BACK ACROSS NORTHERN ILLINOIS. THIS LOOKS TO
SET THE STAGE FOR ANOTHER MORNING OF LOW CIGS AND LOW VIS ACROSS THE
AREA...POTENTIALLY AS LOW AS 500-900 FEET AGL. THE CURRENT TIMING OF
09 UTC STILL APPEARS GOOD. HOWEVER...SOME FEW AND SCT CLOUDS HAVE
BEEN DEVELOPING AROUND 1500 AGL...SO THE CONDITIONS ARE ARE SETTING
UP FOR LOW CIGS ALREADY. GIVEN THAT THE DEW POINTS WILL INCREASE A
GOOD 7 TO 10 DEGREES AT THE TERMINALS OVERNIGHT...I EXPECT THERE
WILL ALSO BE AT LEAST SOME MVFR VIS IN THE 3 TO 5 MILE RANGE. THIS
ACTIVITY WILL LIKELY BE SLOW TO IMPROVE DURING THE MORNING...WITH NO
BIG IMPROVEMENTS UNTIL AFTER 17-18 UTC.
THE OTHER CONCERN IS THE CHANCES AND TIMING OF ANY CONVECTIVE
ACTIVITY OVER THE NEXT 24 TO 30 HOURS. REGIONAL RADAR IMAGERY
INDICATES SOME ISOLATED ACTIVITY OUT WEST NEAR THE MISSISSIPPI. SOME
ADDITIONAL WIDELY SCATTERED ACTIVITY WILL BE POSSIBLE OVER THE NEXT
FEW HOURS ACROSS PORTIONS OF WESTERN ILLINOIS. HOWEVER...IT APPEARS
THAT THE TERMINALS WILL REMAIN DRY THROUGH THE REST OF THE OVERNIGHT
PERIOD. IT STILL APPEARS THERE WILL BE A CHANCE OF
SHOWER/THUNDERSTORM ACTIVITY DURING THE MID TO LATE MORNING HOURS AS
A MID LEVEL DISTURBANCE APPROACHES THE AREA. I HAVE DECIDED TO
CONTINUE WITH THE PROB30 MENTION...AS OVERALL CONFIDENCE IN THUNDER
REMAINS LOW TO MEDIUM.
ADDITIONAL ROUNDS OF THUNDERSTORMS ARE POSSIBLE AGAIN TONIGHT.
HOWEVER...IT APPEARS AT THIS TIME THAT THE MAIN AXIS FOR STORMS WILL
SHIFT NORTHWARD ACROSS SOUTHERN WISCONSIN.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW-MEDIUM CONFIDENCE WITH -SHRA/TSRA TIMING.
* HIGH CONFIDENCE WITH MVFR CEILINGS...MEDIUM-HIGH CONFIDENCE
WITH IFR CEILINGS...AND LOW-MEDIUM CONFIDENCE WITH LIFR
CEILINGS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC OF TSRA.
FRIDAY NIGHT...SHRA..CHC OF TSRA.
SATURDAY...CHC OF TSRA. SHRA MAINLY IN THE EVENING. GUSTY SW WIND.
SUNDAY...CHC OF SHRA.
MONDAY-TUESDAY...VFR.
ZEBIC
&&
.MARINE...
241 PM...A FRONTAL BOUNDARY OVER CENTRAL ILLINOIS AND NORTHERN
INDIANA WILL BEGIN LIFTING NORTH AS WARM FRONT TONIGHT AND WILL
REACH NORTH CENTRAL LAKE MICHIGAN BY THURSDAY EVENING AS IT BEGINS
TO SLOW AND EVENTUALLY STALL AS STRONGER LOW PRESSURE DEVELOPS
OVER THE CENTRAL PLAINS THURSDAY NIGHT INTO FRIDAY MORNING. THIS
FRONT MAY DRIFT BACK SOUTH SLIGHTLY UNTIL TURNING BACK INTO A WARM
FRONT AND LIFTING NORTH OF THE LAKE SATURDAY AFTERNOON OR SATURDAY
NIGHT. NORTH OF THIS BOUNDARY...NORTHEASTERLY WINDS WILL INCREASE
IN SPEED FRIDAY NIGHT AND TURN MORE EASTERLY BY SATURDAY MORNING.
THERE STILL REMAINS SOME UNCERTAINTY REGARDING THE TRACK AND
STRENGTHEN OF THIS LOW AS IS APPROACHES THE LAKES REGION FRIDAY
INTO SATURDAY AS WELL AS WHEN IT PASSES ACROSS THE NORTHERN LAKES
SUNDAY INTO SUNDAY NIGHT. FOR NOW HAVE MAINTAINED 15-25KTS AS
CONFIDENCE REMAINS LOW REGARDING THIS SYSTEM. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1019 PM CDT WED OCT 2 2013
.DISCUSSION...
903 PM CDT
FOR EVENING UPDATE...
HAVE LOWERED POPS OVERALL THROUGH 09Z TONIGHT BASED ON RADAR AND
HIGH-RES SHORT TERM GUIDANCE TRENDS. HAVE ALSO RAISED MINS A
LITTLE OVERNIGHT WITH WARM FRONT LIFTING ACROSS AREA AND FAIRLY
EXTENSIVE MID-HIGH CLOUD COVER ESPECIALLY SOUTH/EAST.
WARM FRONT WAS ANALYZED FROM ROUGHLY NEAR STERLING IL EAST-
SOUTHEAST INTO SOUTHERN WILL COUNTY AND JUST NORTH OF THE KANKAKEE
RIVER VALLEY IN NORTHWEST INDIANA AT 01Z. A FEW ISOLATED SHOWERS
HAD DEVELOPED THIS AFTERNOON ALONG THE EASTERN PORTION OF THE WARM
FRONT...AS WELL AS A FEW FARTHER SOUTH INTO EAST CENTRAL IL ALONG
A DIFFERENTIAL HEATING BOUNDARY LEFT OVER FROM THE NORTH SIDE OF
THE STRATUS DECK WHICH ERODED ACROSS CENTRAL IL EARLIER TODAY.
HOWEVER SUNSET...AND THE LOSS OF DIURNAL INSTABILITY IN THE
BOUNDARY LAYER HAS ALLOWED THESE ISOLATED SHOWERS TO DISSIPATE AT
THIS TIME. LOW LEVEL FRONTAL ZONE REMAINS QUITE SHARP PARTICULARLY
AS INDICATED BY 925 MB ANALYSIS FROM 00Z...AND MAY CONTINUE TO
PRESENT A MECHANISM FOR PRODUCING ISOLATED SHOWERS ALONG AND NORTH
OF THE FRONT THIS EVENING. TRENDS FROM HIGH-RES SHORT RANGE
GUIDANCE FROM WRF- NMM...WRF-ARW AND HRRR SEEM TO INDICATE A LULL
THROUGH THE REMAINDER OF THE EVENING AND EARLY OVERNIGHT HOURS
HOWEVER...INDICATING PERHAPS A LITTLE BETTER POTENTIAL FOR SHOWERS
IN THE 09-12Z TIME FRAME OF EARLY THURSDAY MORNING. THIS APPEARS
TO BE LINKED TO APPROACH OF SHORT WAVE TROUGH MID-MISSOURI VALLEY
THIS EVENING...AND SOME INCREASE IN MOISTURE TRANSPORT FROM POOL
OF HIGHER 925-850 MB DEW POINT AIR NOTED UPSTREAM. ASIDE FROM
FRONTAL ZONE HOWEVER...FORCING APPEARS FAIRLY SUBTLE HOWEVER AND
SUSPECT POPS COULD EVEN BE OVERDONE INTO THURSDAY MORNING. WITH
SOME UNCERTAINTY WILL LIMIT CHANGES TO JUST PUSHING BACK TIMING OF
BETTER PRECIP POTENTIAL TO PRE-DAWN HOURS AS INDICATED.
OTHERWISE...ONLY MINOR CHANGES TO SKY COVER AND TEMPS AS INDICATED
PREVIOUSLY.
RATZER
//PREV DISCUSSION...
329 PM CDT
MAIN FORECAST CONCERN WILL BE WITH TEMPERATURES AND PCPN CHANCES FOR
THE NEXT FEW DAYS.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING...CONDITIONS
WILL BE QUIET...BUT WILL NEED TO CLOSELY MONITOR THE RETURN
NORTHWARD OF THE FRONTAL BOUNDARY THAT PUSHED SOUTH THROUGH THE AREA
LAST NIGHT. LATEST SATELLITE IMAGERY SHOWS THAT THE STRATUS DECK
ALONG AND SOUTH OF THE BOUNDARY...WHICH EXTENDS GENERALLY ALONG THE
ILLINOIS/KANKAKEE RIVERS...HAS ERODED AND TEMPERATURES ACROSS THE
ENTIRE AREA HAVE CLIMBED INTO THE MIDDLE TO UPPER 70S...WITH SOME 80
DEGREE READING LIKELY BEFORE SUNSET. THE PRIMARY CONTRAST ALONG THE
BOUNDARY WILL BE A WIND SHIFT AND A STRONG DEWPOINT CONTRAST RATHER
THAN A TEMPERATURE CONTRAST. AT ISSUANCE TIME...DEWPOINTS SOUTH OF
THE BOUNDARY ARE IN THE MIDDLE TO UPPER 60S...WHILE NORTH OF THE
FRONT...DEWPOINTS ARE ONLY IN THE LOWER TO MIDDLE 40S. THE BOUNDARY
IS EXPECTED TO SURGE NORTH THROUGH THE EVENING...BRINGING THE HIGH
MOISTURE CONTENT AIR BACK ACROSS THE THE ENTIRE REGION. THIS SURGE
OF MOISTURE RIDING ON THE NOSE OF STRENGTHENING LOW LEVEL LOW LEVEL
FLOW...INCREASING WARM ADVECTION AND ISENTROPIC LIFT WILL BRING AN
INCREASING CHANCE OF SHOWERS AND A FEW THUNDERSTORMS TO THE
REGION...WITH AN INCREASING POP TREND BOTH TEMPORALLY AND SPATIALLY
THROUGH THE EVENING AND OVERNIGHT.
THE LOCAL AREA WILL REMAIN SOLIDLY IN WARM SECTOR AIR WITH MAX
TEMPERATURES OVER THE NEXT COUPLE DAYS INCREASING A FEW DEGREES EACH
DAY THROUGH FRIDAY AS UPPER RIDGING BUILDS IN ADVANCE OF A DEEP
CLOSED LOW WHICH IS ONLY NOW MOVING INTO THE PACIFIC NORTHWEST. FOR
THURSDAY...EXPECTING TEMPERATURES TO RANGE FROM THE UPPER 70S TO
LOWER 80S. MODEST SOUTHERLY-SWLY FLOW THROUGH THE LOWER LEVELS...DO
NOT EXPECT A LAKE BREEZE TO DEVELOP AND THE WARMER AIR SHOULD SPREAD
RIGHT UP TO THE LAKEFRONT...AND EVEN DOWNTOWN CHICAGO SHOULD SEE
TEMPERATURES PEG AROUND 80F. BY FRIDAY...THE WARM FRONT SHOULD
BECOME QUASI-STATIONARY ACROSS CENTRAL WISCONSIN AND MIDWAY UP LAKE
MICHIGAN AS A SFC TROUGHING DEVELOPS OVER THE CNTRL PLAINS AS THE
UPPER LOW SWINGS THROUGH THE CNTRL ROCKIES AND EJECTS OUT OVER THE
CNTRL PLAINS. AS THE UPPER LEVEL SYSTEM IS ONLY NOW BEGINNING TO BE
SAMPLED BY REAL DATA...THE MODEL TRENDS AND CHANGING A BIT FROM
RECENT RUNS. THE MAIN TREND HAS BEEN TO SLOW THE PROGRESSION OF THE
UPPER LEVEL SYSTEM AND THE ASSOCIATED COLD FRONT...WITH THE FRONT
ONLY REACHING THE MIDDLE MISSISSIPPI VALLEY BY SATURDAY. SO...IN
THE MEAN TIME...THE WARMING TREND SHOULD CONTINUE FOR AN ADDITIONAL
DAY. THIS ADDITIONAL PERIOD OF STRONG WARM/MOIST ADVECTION ACROSS
THE REGION...EXPECT NOW THAT TEMPS ON FRIDAY SHOULD RANGE FROM THE
LOWER 80S ALONG THE WISCONSIN...INCREASING TO THE MIDDLE TO UPPER
80S SOUTH OF THE I-80 CORRIDOR. WITH SFC DEWPOINTS IN THE MIDDLE TO
UPPER 60S FOR THURSDAY AND FRIDAY...CONDITIONS WILL CERTAINLY BE
UNSEASONABLY WARM AND HUMID.
UNDER THE PERSISTENT WARM/MOIST ADVECTION...PCPN CHANCES WILL BE
HIGH WITH POPS IN THE LIKELY TO CATEGORICAL RANGES THROUGH MUCH OF
THE TIME FROM LATE TONIGHT THROUGH FRIDAY NIGHT...STRICTLY FROM THE
WARM ADVECTIVE PATTERN. BY SATURDAY...THE APPROACHING COLD FRONT
WILL BECOME THE MAJOR WEATHER PLAYER...KEEPING ENHANCED PCPN CHANCES
OVER THE AREA THROUGH MUCH OF THE WEEKEND. THE MAIN CHANCE TO THE
GOING FORECAST HAS BEEN TO SLOW DOWN THE PROGRESSION OF THE UPPER
LOW AND ASSOCIATED SFC COLD FRONT. THE LATEST GUIDANCE...IN
PARTICULAR THE GFS/ECMWF IS TRENDING AROUND 12 HOURS SLOWER THAN
PREVIOUS RUNS...WITH THE NAM A FAST OUTLIER. GENERALLY...PREFER THE
SLOWER SOLUTIONS AS THE UPPER LOW DIGS SOUTHWARD AND TAKES SOME TIME
DEEPENING OVER THE SOUTH HIGH PLAINS BEFORE KICKING OUT TO THE
NORTHEAST. TOTAL PCPN ACROSS THE AREA FROM LATE TONIGHT THROUGH
SATURDAY NIGHT SHOULD RANGE FROM 0.5-0.75 INCHES OVER THE SERN
PORTIONS OF THE CWA...TO ALMOST 1.5 INCHES OVER THE ROCKFORD AREA.
BY THE TIME THAT THE SYSTEM REACHES THE UPPER MISSISSIPPI VALLEY ON
SATURDAY...FORECAST PWATS ARE EXPECTED TO INCREASE TO 1.5 - 1.75
INCHES. FOR EARLY OCTOBER...THIS IS IN THE 99TH PERCENTILE PER THE
KDVN PWAT CLIMATOLOGY. GIVEN THIS EXTREME LEVEL OF DEEP LAYER
MOISTURE SETTING UP FOR THE NEXT FEW DAYS...THERE IS A CHANCE THAT
THE QPF IN THE CURRENT FORECAST MAY BE A BIT LOW AND THERE IS A
SIGNIFICANT CHANCE THAT MEASURED PCPN COULD BE HIGHER THAT CURRENTLY
INDICATED. CERTAINLY...THERE WILL LIKELY BE LOCALLY HIGHER AMOUNTS
AROUND STRONGER SHOWERS OR THUNDERSTORMS.
FOR THE EXTENDED FORECAST PERIOD...FROM SUNDAY THROUGH
WEDNESDAY...WEATHER SHOULD BE SIGNIFICANTLY QUIETER FOLLOWING THE
COLD FRONT PASSAGE. COOLER/DRIER AIR SHOULD FILTER IN BEHIND THE
EXITING FRONT AND HIGH PRESSURE BUILDS ACROSS THE NORTHERN PLAINS
AND INTO THE MIDDLE AND UPPER MISSISSIPPI VALLEY. FOR THE EXTENDED
FORECAST PERIOD...EXPECT TEMPERATURES TO BE THE LOWEST ON SUNDAY
WITH HIGHS IN THE UPPER 50S TO LOWER 60S. TEMPERATURES SHOULD THEN
MODERATE BY MIDWEEK...WITH HIGHS IN THE LOWER TO MIDDLE 70S BY
WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* SOUTHEAST WIND SHIFTING TO THE SOUTH THURSDAY MORNING.
* INCREASING CHANCES FOR -SHRA/-TSRA OVERNIGHT INTO THURSDAY.
* LOW CEILINGS AND FOG MOVING OVERHEAD LATE TONIGHT INTO THURSDAY
MORNING...WITH MVFR/IFR CEILINGS LIKELY AND A POSSIBILITY FOR
LIFR CEILINGS.
ZEBIC
//DISCUSSION...UPDATED 00Z...
CLOUDS EXPANDING ACROSS NE ILLINOIS IN ADVANCE OF UPPER LEVEL LOW
PRESSURE TROUGH TRACKING NORTHEAST FROM ARKANSAS. AS SURFACE HIGH
PRESSURE CONTINUES TO MOVE EAST...OVERALL FLOW TO BECOME SOUTHERLY
THEN SOUTHWESTERLY THROUGH THURSDAY.
SURFACE OBSERVATIONS AND RADAR INDICATE WARM FRONT MOVING SLOWLY
INTO NORTHERN ILLINOIS. EARLIER SHOWERS ASSOCIATED WITH FRONT HAVE
DISSIPATED OVERALL. LINGERING CLOUD COVER COMBINED WITH THAT
STREAMING NORTHEAST FROM ARKANSAS IS EXPECTED TO KEEP VISIBILITIES
VFR-MVFR OVERNIGHT. IFR/LIFR CIGS ARE EXPECTED TO REDEVELOP IN
VICINITY OF AND TO NORTH OF WARM FRONT OVERNIGHT THOUGH.
WARM FRONT TO LEAD IN PLENTY OF WARM MOIST AIR THROUGH THURSDAY
MORNING AS WIND TURNS SE-S-SW. PRECIPITATION CHANCES TO GRADUALLY
INCREASE OVERNIGHT AS WARM AIR MOVES IN ALOFT. NE/KS UPPER LEVEL
WAVE TO ARRIVE AFTER DAYBREAK THURSDAY AND ENHANCE PRECIPITATION
COVERAGE. THIS WAVE SHOULD MOVE EAST BY AFTERNOON AND REDUCE
PRECIPITATION CHANCES.
ZEBIC
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN WIND SPEED AND DIRECTION.
* MEDIUM HIGH CONFIDENCE WITH -SHRA AND TIMING...AND MEDIUM
CONFIDENCE WITH -TSRA AND TIMING.
* HIGH CONFIDENCE WITH MVFR CEILINGS...MEDIUM HIGH CONFIDENCE WITH
IFR CEILINGS...AND LOW MEDIUM CONFIDENCE WITH LIFR CEILINGS.
ZEBIC
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC OF TSRA.
FRIDAY NIGHT...SHRA..CHC OF TSRA.
SATURDAY...CHC OF TSRA. SHRA MAINLY IN THE EVENING. GUSTY SW WIND.
SUNDAY...CHC OF SHRA.
MONDAY-TUESDAY...VFR.
ZEBIC
&&
.MARINE...
241 PM...A FRONTAL BOUNDARY OVER CENTRAL ILLINOIS AND NORTHERN
INDIANA WILL BEGIN LIFTING NORTH AS WARM FRONT TONIGHT AND WILL
REACH NORTH CENTRAL LAKE MICHIGAN BY THURSDAY EVENING AS IT BEGINS
TO SLOW AND EVENTUALLY STALL AS STRONGER LOW PRESSURE DEVELOPS
OVER THE CENTRAL PLAINS THURSDAY NIGHT INTO FRIDAY MORNING. THIS
FRONT MAY DRIFT BACK SOUTH SLIGHTLY UNTIL TURNING BACK INTO A WARM
FRONT AND LIFTING NORTH OF THE LAKE SATURDAY AFTERNOON OR SATURDAY
NIGHT. NORTH OF THIS BOUNDARY...NORTHEASTERLY WINDS WILL INCREASE
IN SPEED FRIDAY NIGHT AND TURN MORE EASTERLY BY SATURDAY MORNING.
THERE STILL REMAINS SOME UNCERTAINTY REGARDING THE TRACK AND
STRENGTHEN OF THIS LOW AS IS APPROACHES THE LAKES REGION FRIDAY
INTO SATURDAY AS WELL AS WHEN IT PASSES ACROSS THE NORTHERN LAKES
SUNDAY INTO SUNDAY NIGHT. FOR NOW HAVE MAINTAINED 15-25KTS AS
CONFIDENCE REMAINS LOW REGARDING THIS SYSTEM. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
904 PM CDT WED OCT 2 2013
.DISCUSSION...
903 PM CDT
FOR EVENING UPDATE...
HAVE LOWERED POPS OVERALL THROUGH 09Z TONIGHT BASED ON RADAR AND
HIGH-RES SHORT TERM GUIDANCE TRENDS. HAVE ALSO RAISED MINS A
LITTLE OVERNIGHT WITH WARM FRONT LIFTING ACROSS AREA AND FAIRLY
EXTENSIVE MID-HIGH CLOUD COVER ESPECIALLY SOUTH/EAST.
WARM FRONT WAS ANALYZED FROM ROUGHLY NEAR STERLING IL EAST-
SOUTHEAST INTO SOUTHERN WILL COUNTY AND JUST NORTH OF THE KANKAKEE
RIVER VALLEY IN NORTHWEST INDIANA AT 01Z. A FEW ISOLATED SHOWERS
HAD DEVELOPED THIS AFTERNOON ALONG THE EASTERN PORTION OF THE WARM
FRONT...AS WELL AS A FEW FARTHER SOUTH INTO EAST CENTRAL IL ALONG
A DIFFERENTIAL HEATING BOUNDARY LEFT OVER FROM THE NORTH SIDE OF
THE STRATUS DECK WHICH ERODED ACROSS CENTRAL IL EARLIER TODAY.
HOWEVER SUNSET...AND THE LOSS OF DIURNAL INSTABILITY IN THE
BOUNDARY LAYER HAS ALLOWED THESE ISOLATED SHOWERS TO DISSIPATE AT
THIS TIME. LOW LEVEL FRONTAL ZONE REMAINS QUITE SHARP PARTICULARLY
AS INDICATED BY 925 MB ANALYSIS FROM 00Z...AND MAY CONTINUE TO
PRESENT A MECHANISM FOR PRODUCING ISOLATED SHOWERS ALONG AND NORTH
OF THE FRONT THIS EVENING. TRENDS FROM HIGH-RES SHORT RANGE
GUIDANCE FROM WRF- NMM...WRF-ARW AND HRRR SEEM TO INDICATE A LULL
THROUGH THE REMAINDER OF THE EVENING AND EARLY OVERNIGHT HOURS
HOWEVER...INDICATING PERHAPS A LITTLE BETTER POTENTIAL FOR SHOWERS
IN THE 09-12Z TIME FRAME OF EARLY THURSDAY MORNING. THIS APPEARS
TO BE LINKED TO APPROACH OF SHORT WAVE TROUGH MID-MISSOURI VALLEY
THIS EVENING...AND SOME INCREASE IN MOISTURE TRANSPORT FROM POOL
OF HIGHER 925-850 MB DEW POINT AIR NOTED UPSTREAM. ASIDE FROM
FRONTAL ZONE HOWEVER...FORCING APPEARS FAIRLY SUBTLE HOWEVER AND
SUSPECT POPS COULD EVEN BE OVERDONE INTO THURSDAY MORNING. WITH
SOME UNCERTAINTY WILL LIMIT CHANGES TO JUST PUSHING BACK TIMING OF
BETTER PRECIP POTENTIAL TO PRE-DAWN HOURS AS INDICATED.
OTHERWISE...ONLY MINOR CHANGES TO SKY COVER AND TEMPS AS INDICATED
PREVIOUSLY.
RATZER
&&
.PREV DISCUSSION...
329 PM CDT
MAIN FORECAST CONCERN WILL BE WITH TEMPERATURES AND PCPN CHANCES FOR
THE NEXT FEW DAYS.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING...CONDITIONS
WILL BE QUIET...BUT WILL NEED TO CLOSELY MONITOR THE RETURN
NORTHWARD OF THE FRONTAL BOUNDARY THAT PUSHED SOUTH THROUGH THE AREA
LAST NIGHT. LATEST SATELLITE IMAGERY SHOWS THAT THE STRATUS DECK
ALONG AND SOUTH OF THE BOUNDARY...WHICH EXTENDS GENERALLY ALONG THE
ILLINOIS/KANKAKEE RIVERS...HAS ERODED AND TEMPERATURES ACROSS THE
ENTIRE AREA HAVE CLIMBED INTO THE MIDDLE TO UPPER 70S...WITH SOME 80
DEGREE READING LIKELY BEFORE SUNSET. THE PRIMARY CONTRAST ALONG THE
BOUNDARY WILL BE A WIND SHIFT AND A STRONG DEWPOINT CONTRAST RATHER
THAN A TEMPERATURE CONTRAST. AT ISSUANCE TIME...DEWPOINTS SOUTH OF
THE BOUNDARY ARE IN THE MIDDLE TO UPPER 60S...WHILE NORTH OF THE
FRONT...DEWPOINTS ARE ONLY IN THE LOWER TO MIDDLE 40S. THE BOUNDARY
IS EXPECTED TO SURGE NORTH THROUGH THE EVENING...BRINGING THE HIGH
MOISTURE CONTENT AIR BACK ACROSS THE THE ENTIRE REGION. THIS SURGE
OF MOISTURE RIDING ON THE NOSE OF STRENGTHENING LOW LEVEL LOW LEVEL
FLOW...INCREASING WARM ADVECTION AND ISENTROPIC LIFT WILL BRING AN
INCREASING CHANCE OF SHOWERS AND A FEW THUNDERSTORMS TO THE
REGION...WITH AN INCREASING POP TREND BOTH TEMPORALLY AND SPATIALLY
THROUGH THE EVENING AND OVERNIGHT.
THE LOCAL AREA WILL REMAIN SOLIDLY IN WARM SECTOR AIR WITH MAX
TEMPERATURES OVER THE NEXT COUPLE DAYS INCREASING A FEW DEGREES EACH
DAY THROUGH FRIDAY AS UPPER RIDGING BUILDS IN ADVANCE OF A DEEP
CLOSED LOW WHICH IS ONLY NOW MOVING INTO THE PACIFIC NORTHWEST. FOR
THURSDAY...EXPECTING TEMPERATURES TO RANGE FROM THE UPPER 70S TO
LOWER 80S. MODEST SOUTHERLY-SWLY FLOW THROUGH THE LOWER LEVELS...DO
NOT EXPECT A LAKE BREEZE TO DEVELOP AND THE WARMER AIR SHOULD SPREAD
RIGHT UP TO THE LAKEFRONT...AND EVEN DOWNTOWN CHICAGO SHOULD SEE
TEMPERATURES PEG AROUND 80F. BY FRIDAY...THE WARM FRONT SHOULD
BECOME QUASI-STATIONARY ACROSS CENTRAL WISCONSIN AND MIDWAY UP LAKE
MICHIGAN AS A SFC TROUGHING DEVELOPS OVER THE CNTRL PLAINS AS THE
UPPER LOW SWINGS THROUGH THE CNTRL ROCKIES AND EJECTS OUT OVER THE
CNTRL PLAINS. AS THE UPPER LEVEL SYSTEM IS ONLY NOW BEGINNING TO BE
SAMPLED BY REAL DATA...THE MODEL TRENDS AND CHANGING A BIT FROM
RECENT RUNS. THE MAIN TREND HAS BEEN TO SLOW THE PROGRESSION OF THE
UPPER LEVEL SYSTEM AND THE ASSOCIATED COLD FRONT...WITH THE FRONT
ONLY REACHING THE MIDDLE MISSISSIPPI VALLEY BY SATURDAY. SO...IN
THE MEAN TIME...THE WARMING TREND SHOULD CONTINUE FOR AN ADDITIONAL
DAY. THIS ADDITIONAL PERIOD OF STRONG WARM/MOIST ADVECTION ACROSS
THE REGION...EXPECT NOW THAT TEMPS ON FRIDAY SHOULD RANGE FROM THE
LOWER 80S ALONG THE WISCONSIN...INCREASING TO THE MIDDLE TO UPPER
80S SOUTH OF THE I-80 CORRIDOR. WITH SFC DEWPOINTS IN THE MIDDLE TO
UPPER 60S FOR THURSDAY AND FRIDAY...CONDITIONS WILL CERTAINLY BE
UNSEASONABLY WARM AND HUMID.
UNDER THE PERSISTENT WARM/MOIST ADVECTION...PCPN CHANCES WILL BE
HIGH WITH POPS IN THE LIKELY TO CATEGORICAL RANGES THROUGH MUCH OF
THE TIME FROM LATE TONIGHT THROUGH FRIDAY NIGHT...STRICTLY FROM THE
WARM ADVECTIVE PATTERN. BY SATURDAY...THE APPROACHING COLD FRONT
WILL BECOME THE MAJOR WEATHER PLAYER...KEEPING ENHANCED PCPN CHANCES
OVER THE AREA THROUGH MUCH OF THE WEEKEND. THE MAIN CHANCE TO THE
GOING FORECAST HAS BEEN TO SLOW DOWN THE PROGRESSION OF THE UPPER
LOW AND ASSOCIATED SFC COLD FRONT. THE LATEST GUIDANCE...IN
PARTICULAR THE GFS/ECMWF IS TRENDING AROUND 12 HOURS SLOWER THAN
PREVIOUS RUNS...WITH THE NAM A FAST OUTLIER. GENERALLY...PREFER THE
SLOWER SOLUTIONS AS THE UPPER LOW DIGS SOUTHWARD AND TAKES SOME TIME
DEEPENING OVER THE SOUTH HIGH PLAINS BEFORE KICKING OUT TO THE
NORTHEAST. TOTAL PCPN ACROSS THE AREA FROM LATE TONIGHT THROUGH
SATURDAY NIGHT SHOULD RANGE FROM 0.5-0.75 INCHES OVER THE SERN
PORTIONS OF THE CWA...TO ALMOST 1.5 INCHES OVER THE ROCKFORD AREA.
BY THE TIME THAT THE SYSTEM REACHES THE UPPER MISSISSIPPI VALLEY ON
SATURDAY...FORECAST PWATS ARE EXPECTED TO INCREASE TO 1.5 - 1.75
INCHES. FOR EARLY OCTOBER...THIS IS IN THE 99TH PERCENTILE PER THE
KDVN PWAT CLIMATOLOGY. GIVEN THIS EXTREME LEVEL OF DEEP LAYER
MOISTURE SETTING UP FOR THE NEXT FEW DAYS...THERE IS A CHANCE THAT
THE QPF IN THE CURRENT FORECAST MAY BE A BIT LOW AND THERE IS A
SIGNIFICANT CHANCE THAT MEASURED PCPN COULD BE HIGHER THAT CURRENTLY
INDICATED. CERTAINLY...THERE WILL LIKELY BE LOCALLY HIGHER AMOUNTS
AROUND STRONGER SHOWERS OR THUNDERSTORMS.
FOR THE EXTENDED FORECAST PERIOD...FROM SUNDAY THROUGH
WEDNESDAY...WEATHER SHOULD BE SIGNIFICANTLY QUIETER FOLLOWING THE
COLD FRONT PASSAGE. COOLER/DRIER AIR SHOULD FILTER IN BEHIND THE
EXITING FRONT AND HIGH PRESSURE BUILDS ACROSS THE NORTHERN PLAINS
AND INTO THE MIDDLE AND UPPER MISSISSIPPI VALLEY. FOR THE EXTENDED
FORECAST PERIOD...EXPECT TEMPERATURES TO BE THE LOWEST ON SUNDAY
WITH HIGHS IN THE UPPER 50S TO LOWER 60S. TEMPERATURES SHOULD THEN
MODERATE BY MIDWEEK...WITH HIGHS IN THE LOWER TO MIDDLE 70S BY
WEDNESDAY.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* EAST WIND BECOMING SOUTHEAST THIS EVENING AND SHIFTING TO THE
SOUTH THURSDAY MORNING.
* INCREASING CHANCES FOR -SHRA/-TSRA LATE TONIGHT INTO THURSDAY.
* LOW CEILINGS AND FOG MOVING OVERHEAD LATE TONIGHT INTO THURSDAY
MORNING...WITH MVFR/IFR CEILINGS LIKELY AND A POSSIBILITY FOR
LIFR CEILINGS.
ZEBIC
//DISCUSSION...UPDATED 00Z...
CLOUDS EXPANDING ACROSS NE ILLINOIS IN ADVANCE OF UPPER LEVEL LOW
PRESSURE TROUGH TRACKING NORTHEAST FROM ARKANSAS. AS SURFACE HIGH
PRESSURE CONTINUES TO MOVE EAST...OVERALL FLOW TO BECOME SOUTHERLY
THEN SOUTHWESTERLY THROUGH THURSDAY.
SURFACE OBSERVATIONS AND RADAR INDICATE WARM FRONT MOVING SLOWLY
INTO NORTHERN ILLINOIS. EARLIER SHOWERS ASSOCIATED WITH FRONT HAVE
DISSIPATED OVERALL. LINGERING CLOUD COVER COMBINED WITH THAT
STREAMING NORTHEAST FROM ARKANSAS IS EXPECTED TO KEEP VISIBILITIES
VFR-MVFR OVERNIGHT. IFR/LIFR CIGS ARE EXPECTED TO REDEVELOP IN
VICINITY OF AND TO NORTH OF WARM FRONT OVERNIGHT THOUGH.
WARM FRONT TO LEAD IN PLENTY OF WARM MOIST AIR THROUGH THURSDAY
MORNING AS WIND TURNS SE-S-SW. PRECIPITATION CHANCES TO GRADUALLY
INCREASE OVERNIGHT AS WARM AIR MOVES IN ALOFT. NE/KS UPPER LEVEL
WAVE TO ARRIVE AFTER DAYBREAK THURSDAY AND ENHANCE PRECIPITATION
COVERAGE. THIS WAVE SHOULD MOVE EAST BY AFTERNOON AND REDUCE
PRECIPITATION CHANCES.
ZEBIC
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN WIND SPEED AND DIRECTION.
* MEDIUM HIGH CONFIDENCE WITH -SHRA AND TIMING...AND MEDIUM
CONFIDENCE WITH -TSRA AND TIMING.
* HIGH CONFIDENCE WITH MVFR CEILINGS...MEDIUM HIGH CONFIDENCE WITH
IFR CEILINGS...AND LOW MEDIUM CONFIDENCE WITH LIFR CEILINGS.
ZEBIC
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHC OF TSRA.
FRIDAY NIGHT...SHRA..CHC OF TSRA.
SATURDAY...CHC OF TSRA. SHRA MAINLY IN THE EVENING. GUSTY SW
WIND.
SUNDAY...CHC OF SHRA.
MONDAY-TUESDAY...VFR.
ZEBIC
&&
.MARINE...
241 PM...A FRONTAL BOUNDARY OVER CENTRAL ILLINOIS AND NORTHERN
INDIANA WILL BEGIN LIFTING NORTH AS WARM FRONT TONIGHT AND WILL
REACH NORTH CENTRAL LAKE MICHIGAN BY THURSDAY EVENING AS IT BEGINS
TO SLOW AND EVENTUALLY STALL AS STRONGER LOW PRESSURE DEVELOPS
OVER THE CENTRAL PLAINS THURSDAY NIGHT INTO FRIDAY MORNING. THIS
FRONT MAY DRIFT BACK SOUTH SLIGHTLY UNTIL TURNING BACK INTO A WARM
FRONT AND LIFTING NORTH OF THE LAKE SATURDAY AFTERNOON OR SATURDAY
NIGHT. NORTH OF THIS BOUNDARY...NORTHEASTERLY WINDS WILL INCREASE
IN SPEED FRIDAY NIGHT AND TURN MORE EASTERLY BY SATURDAY MORNING.
THERE STILL REMAINS SOME UNCERTAINTY REGARDING THE TRACK AND
STRENGTHEN OF THIS LOW AS IS APPROACHES THE LAKES REGION FRIDAY
INTO SATURDAY AS WELL AS WHEN IT PASSES ACROSS THE NORTHERN LAKES
SUNDAY INTO SUNDAY NIGHT. FOR NOW HAVE MAINTAINED 15-25KTS AS
CONFIDENCE REMAINS LOW REGARDING THIS SYSTEM. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
657 AM CDT FRI OCT 4 2013
.UPDATE...
ISSUED AT 648 AM CDT FRI OCT 4 2013
THE FIRST STORM COMPLEX IS MOVING INTO SOUTHERN WISCONSIN. THE
NEXT STORM SYSTEM IN WESTERN/CENTRAL IOWA IS SLOWLY FALLING APART
BUT ISOLATED TO SCATTERED SHOWERS AND SOME THUNDERSTORMS WILL BE
POSSIBLE THROUGH LATE MORNING.
THERE ARE CONCERNS ABOUT TEMPERATURES DUE TO CLOUD COVER AND THE
REMNANT COLD POOL FROM THE OVERNIGHT STORMS. THE COLD POOL AND
CLOUD COVER MAY SUPPRESS TEMPERATURES ACROSS THE NORTHERN CWFA
DURING THE DAY WITH COOLER THAN EXPECTED READINGS. THE EDGE OF THE
COLD POOL WILL ALSO PROVIDE A BOUNDARY FOR ISOLATED TO SCATTERED
CONVECTION DURING THE AFTERNOON AND EVENING HOURS.
&&
.SYNOPSIS...
ISSUED AT 248 AM CDT FRI OCT 4 2013
06Z SFC ANALYSIS HAD A WEAK LOW NEAR KOLZ WITH ADDITIONAL LOWS FROM
NORTHWEST KANSAS INTO SOUTHEAST COLORADO. THE MAIN FRONT RAN FROM
UPPER MICHIGAN...TO NEAR KOLZ...BACK TO AROUND KHLC. WEAK BOUNDARIES
FROM CONVECTION WERE ACROSS NORTHERN ILLINOIS AND EASTERN IOWA. DEW
POINTS WERE IN THE 60S SOUTH AND EAST OF THE FRONT WITH 40S AND 50S
BEHIND THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 248 AM CDT FRI OCT 4 2013
THE CURRENT CONVECTION IS BEING SUPPORTED BY A DISTURBANCE ALOFT.
PER THE GEM REGIONAL AND RAP TRENDS THIS SHORTWAVE WILL ALLOW
CONVECTION TO PERSIST THROUGH SUNRISE AND THE MORNING HOURS
GENERALLY NORTH OF I-80. INTERACTION WITH BOUNDARIES MAY ALLOW
ISOLATED CONVECTION TO DEVELOP JUST SOUTH OF I-80.
ONCE THE SHORTWAVE PASSES A LULL IN PRECIPITATION SHOULD BE SEEN
THROUGH THE AFTERNOON. DIFFERENTIAL HEATING MAY ALLOW ISOLATED TO
LOW END SCATTERED CONVECTION TO DEVELOP DURING THE HEAT OF THE DAY.
THE SEVERE WEATHER THREAT TODAY APPEARS TO BE LOW RIGHT NOW.
TEMPERATURES WILL BE HIGHLY DEPENDENT UPON CLOUD COVER AND
PRECIPITATION. THE POTENTIAL DOES EXIST FOR A 15 DEGREE GRADIENT
ACROSS THE AREA WITH THE COOLEST READINGS IN THE HWY 20 CORRIDOR.
TONIGHT...ISOLATED TO LOW END SCATTERED CONVECTION SHOULD BE SEEN
DURING THE EVENING. BETTER FORCING ASSOCIATED WITH THE MAIN COLD
FRONT IS EXPECTED TO ALLOW MORE WIDESPREAD CONVECTION TO DEVELOP
DURING THE LATE EVENING AND OVERNIGHT HOURS THAT MOVES FROM WEST TO
EAST ACROSS THE CWFA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 248 AM CDT FRI OCT 4 2013
EARLY FALL COLD TO BRING COLDEST AIR OF THE FALL WITH RISK OF
PATCHY FROST WITH DRY WEATHER AFTER ITS PASSAGE.
OVERVIEW...INITIALIZATION AND VERIFICATION FAIR WITH ONGOING
PROBLEMS WITH COLD AIR IN PLAINS UNDERDONE. THIS HAS BEEN THE CASE
THE PAST 24 PLUS HOURS WITH A MORE SOUTHERLY AND TRACK OF LOW AND
ALSO COLDER WEATHER AFTER FRONT. THIS IS RELATED TO STRONG NEGATIVE
FEEDBACK ISSUES OF MAJOR SNOWS IN NORTHERN HIGH PLAINS AND DEEP
MOIST AIR. SOME FURTHER SHIFT OF LOW TRACK SUPPORTED NEXT 24 HOURS
WITH UPPER LOW PASSING OVER AT LEAST NORTH SECTIONS WITH A DEEPLY
OCCLUDED LOW SYSTEM ON SUNDAY. CONTINUITY AND THERMAL FIELDS
SUPPORTS A 70/30 MIX OF HI-RES ECMWF AND GFS. THIS WOULD SUGGEST
COLDER TEMPERATURES AFTER FRONTAL PASSAGE AND SLIGHT COLDER TEMPERATURES
INTO TUESDAY AM FOR LATER SHIFTS.
SATURDAY...DEEPLY OCCLUDED SURFACE FRONT TO PASS IN AM WITH LIMITED
INSTABILITY FOR SHOWERS AND ISOLATED EMBEDDED STORMS THAT WOULD NOT
BE SEVERE. RAISED POPS WITH DEEPER FORCING WITH WIDESPREAD MODERATE
RAIN AMOUNTS WITH PASSAGE. FALLING TEMPERATURES MOST OF THE REGION
BY MID/LATE PM WITH BLUSTERY WESTERLY WINDS. SATURDAY NIGHT..DRY
SLOW FOR CLEAR TO PARTLY CLOUDY SKIES AND LOW DEWPOINT AND LOTS OF
COLD AIR ALOFT MAY ALLOW FOR UPPER 30S FOR LATER SHIFTS TO
REASSESS. THIS MAY ALSO BE NEEDED WITH COLDER TRENDS FROM NEGATIVE
FEEDBACK ISSUES DISCUSSED EARLIER. IF FRONT ARRIVES SOONER THEN
HIGHS WILL NEED LOWERING BY 5 DEGREES OR MORE FOR LATER SHIFTS TO
RECONSIDER.
SUNDAY...INCREASED POPS...CLOUDS AND A BIT COLDER WITH NW SECTIONS
POSSIBLY NEEDING LOWERING BY AT LEAST ANOTHER CATEGORY WITH NEAR
50F READINGS NOT OUT OF THE QUESTION. LIGHT RAIN AND SHOWERS WITH
DIURNAL HEATING MAY NEED RAISING TO LIKELY OVER NORTHERN SECTIONS
WITH A FEW HUNDREDTHS OF AN INCH...ENOUGH TO WET THE GROUND. BLUSTERY
WESTERLY WINDS OF 15 TO 25 MPH TO MAKE COOLER WEATHER MORE NOTICEABLE.
SUNDAY NIGHT...CLEARING AND COOL WITH KEY QUESTION OF BL DECOUPLING
AND CLEARING...IF THIS OCCURS THEN LOWS TO NEAR FREEZING ARE POSSIBLE
FOR LATER SHIFTS TO REASSESS. THE POOR CONFIDENCE IN MODEL TRENDS
MAKE THIS POOR TO QUANTIFY ATTM.
MONDAY AND TUESDAY...FAIR WITH A WARMING TREND WITH WIDE DIURNAL
TEMPERATURE CHANGES. LATER SHIFTS MAY NEED TO TRIM MINS BY A CATEGORY.
HIGHS IN THE 60S MONDAY AND UPPER 60S TO LOWER 70S TUESDAY WITH LOWS
TUESDAY AM CURRENTLY IN THE MIDDLE 40S.
WEDNESDAY AND THURSDAY...MILD WITH LIGHT TO MODERATE SOUTHERLY WINDS
AND FAIR SKIES TO MAKE NICE EARLY OCTOBER WEATHER. HIGHS IN THE 70S
AND LOWS MOSTLY IN THE LOWER 50S. UPPER 40S IN FAVORED LOW LYING
LOCATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 648 AM CDT FRI OCT 4 2013
THUNDERSTORM COMPLEX ALONG THE MISSISSIPPI RIVER WILL MOVE INTO
SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS. CONDITIONS RANGE
FROM VFR TO IFR DUE TO STORMS AND LOW CLOUDS. MVFR TO VFR
CONDITIONS ARE EXPECTED THROUGH 00Z/05 BUT THE POTENTIAL DOES
EXIST FOR BLO 1KFT CIGS DUE TO HIGH MOISTURE LEVELS IN THE LOWER
ATMOSPHERE AT KMLI/KBRL. ISOLD TO SCT CONVECTION WILL BE POSSIBLE
THROUGH 04Z/05. AFT 04Z/05 A STRONG COLD FRONT WILL SWEEP THROUGH
EASTERN IOWA AND ILLINOIS WITH TSRA POSSIBLE ALONG WITH MVFR
CONDITIONS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
327 AM CDT FRI OCT 4 2013
.SYNOPSIS...
ISSUED AT 248 AM CDT FRI OCT 4 2013
06Z SFC ANALYSIS HAD A WEAK LOW NEAR KOLZ WITH ADDITIONAL LOWS FROM
NORTHWEST KANSAS INTO SOUTHEAST COLORADO. THE MAIN FRONT RAN FROM
UPPER MICHIGAN...TO NEAR KOLZ...BACK TO AROUND KHLC. WEAK BOUNDARIES
FROM CONVECTION WERE ACROSS NORTHERN ILLINOIS AND EASTERN IOWA. DEW
POINTS WERE IN THE 60S SOUTH AND EAST OF THE FRONT WITH 40S AND 50S
BEHIND THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 248 AM CDT FRI OCT 4 2013
THE CURRENT CONVECTION IS BEING SUPPORTED BY A DISTURBANCE ALOFT.
PER THE GEM REGIONAL AND RAP TRENDS THIS SHORTWAVE WILL ALLOW
CONVECTION TO PERSIST THROUGH SUNRISE AND THE MORNING HOURS
GENERALLY NORTH OF I-80. INTERACTION WITH BOUNDARIES MAY ALLOW
ISOLATED CONVECTION TO DEVELOP JUST SOUTH OF I-80.
ONCE THE SHORTWAVE PASSES A LULL IN PRECIPITATION SHOULD BE SEEN
THROUGH THE AFTERNOON. DIFFERENTIAL HEATING MAY ALLOW ISOLATED TO
LOW END SCATTERED CONVECTION TO DEVELOP DURING THE HEAT OF THE DAY.
THE SEVERE WEATHER THREAT TODAY APPEARS TO BE LOW RIGHT NOW.
TEMPERATURES WILL BE HIGHLY DEPENDENT UPON CLOUD COVER AND
PRECIPITATION. THE POTENTIAL DOES EXIST FOR A 15 DEGREE GRADIENT
ACROSS THE AREA WITH THE COOLEST READINGS IN THE HWY 20 CORRIDOR.
TONIGHT...ISOLATED TO LOW END SCATTERED CONVECTION SHOULD BE SEEN
DURING THE EVENING. BETTER FORCING ASSOCIATED WITH THE MAIN COLD
FRONT IS EXPECTED TO ALLOW MORE WIDESPREAD CONVECTION TO DEVELOP
DURING THE LATE EVENING AND OVERNIGHT HOURS THAT MOVES FROM WEST TO
EAST ACROSS THE CWFA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 248 AM CDT FRI OCT 4 2013
EARLY FALL COLD TO BRING COLDEST AIR OF THE FALL WITH RISK OF
PATCHY FROST WITH DRY WEATHER AFTER ITS PASSAGE.
OVERVIEW...INITIALIZATION AND VERIFICATION FAIR WITH ONGOING
PROBLEMS WITH COLD AIR IN PLAINS UNDERDONE. THIS HAS BEEN THE CASE
THE PAST 24 PLUS HOURS WITH A MORE SOUTHERLY AND TRACK OF LOW AND
ALSO COLDER WEATHER AFTER FRONT. THIS IS RELATED TO STRONG NEGATIVE
FEEDBACK ISSUES OF MAJOR SNOWS IN NORTHERN HIGH PLAINS AND DEEP
MOIST AIR. SOME FURTHER SHIFT OF LOW TRACK SUPPORTED NEXT 24 HOURS
WITH UPPER LOW PASSING OVER AT LEAST NORTH SECTIONS WITH A DEEPLY
OCCLUDED LOW SYSTEM ON SUNDAY. CONTINUITY AND THERMAL FIELDS
SUPPORTS A 70/30 MIX OF HI-RES ECMWF AND GFS. THIS WOULD SUGGEST
COLDER TEMPERATURES AFTER FRONTAL PASSAGE AND SLIGHT COLDER TEMPERATURES
INTO TUESDAY AM FOR LATER SHIFTS.
SATURDAY...DEEPLY OCCLUDED SURFACE FRONT TO PASS IN AM WITH LIMITED
INSTABILITY FOR SHOWERS AND ISOLATED EMBEDDED STORMS THAT WOULD NOT
BE SEVERE. RAISED POPS WITH DEEPER FORCING WITH WIDESPREAD MODERATE
RAIN AMOUNTS WITH PASSAGE. FALLING TEMPERATURES MOST OF THE REGION
BY MID/LATE PM WITH BLUSTERY WESTERLY WINDS. SATURDAY NIGHT..DRY
SLOW FOR CLEAR TO PARTLY CLOUDY SKIES AND LOW DEWPOINT AND LOTS OF
COLD AIR ALOFT MAY ALLOW FOR UPPER 30S FOR LATER SHIFTS TO
REASSESS. THIS MAY ALSO BE NEEDED WITH COLDER TRENDS FROM NEGATIVE
FEEDBACK ISSUES DISCUSSED EARLIER. IF FRONT ARRIVES SOONER THEN
HIGHS WILL NEED LOWERING BY 5 DEGREES OR MORE FOR LATER SHIFTS TO
RECONSIDER.
SUNDAY...INCREASED POPS...CLOUDS AND A BIT COLDER WITH NW SECTIONS
POSSIBLY NEEDING LOWERING BY AT LEAST ANOTHER CATEGORY WITH NEAR
50F READINGS NOT OUT OF THE QUESTION. LIGHT RAIN AND SHOWERS WITH
DIURNAL HEATING MAY NEED RAISING TO LIKELY OVER NORTHERN SECTIONS
WITH A FEW HUNDREDTHS OF AN INCH...ENOUGH TO WET THE GROUND. BLUSTERY
WESTERLY WINDS OF 15 TO 25 MPH TO MAKE COOLER WEATHER MORE NOTICEABLE.
SUNDAY NIGHT...CLEARING AND COOL WITH KEY QUESTION OF BL DECOUPLING
AND CLEARING...IF THIS OCCURS THEN LOWS TO NEAR FREEZING ARE POSSIBLE
FOR LATER SHIFTS TO REASSESS. THE POOR CONFIDENCE IN MODEL TRENDS
MAKE THIS POOR TO QUANTIFY ATTM.
MONDAY AND TUESDAY...FAIR WITH A WARMING TREND WITH WIDE DIURNAL
TEMPERATURE CHANGES. LATER SHIFTS MAY NEED TO TRIM MINS BY A CATEGORY.
HIGHS IN THE 60S MONDAY AND UPPER 60S TO LOWER 70S TUESDAY WITH LOWS
TUESDAY AM CURRENTLY IN THE MIDDLE 40S.
WEDNESDAY AND THURSDAY...MILD WITH LIGHT TO MODERATE SOUTHERLY WINDS
AND FAIR SKIES TO MAKE NICE EARLY OCTOBER WEATHER. HIGHS IN THE 70S
AND LOWS MOSTLY IN THE LOWER 50S. UPPER 40S IN FAVORED LOW LYING
LOCATIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 248 AM CDT FRI OCT 4 2013
A LOW CONFIDENCE AND SOMEWHAT STORMY LATE NIGHT OF AVIATION WEATHER
IS EXPECTED. SCATTERED SHOWERS AND SOME THUNDERSTORMS WILL BE FOUND
OVER THE REGION...MAINLY NORTH OF THE IOWA AND MISSOURI BORDER.
THESE WILL CONTINUE TO BECOME MUCH MORE NUMEROUS INTO EARLY FRIDAY
MORNING. THUNDERSTORMS HAVE BEEN INCREASED IN DURATION AT ALL
SITES EXCEPT BRL AS THE WARM FRONT WILL NOT MOVE INTO WISCONSIN...BUT
STAY OVER SOUTHERN IOWA. AFTER A PERIOD OF MORNING SHOWERS AND
STORMS...A BREAK IS EXPECTED UNTIL LATE EVENING WHEN THE COLD
FRONT AND UPPER SYSTEM WILL BRING ANOTHER ROUND OF SHOWERS AND
POSSIBLE STORMS. IN ADDITION TO ALL THIS...THERE IS POTENTIAL FOR
FOG AT DBQ...WHICH IS FAR ENOUGH NORTH OF THE FRONT THAT SOME
GROUND FOG MAY MOVE IN PRIOR TO SUNRISE. THIS IS A CHALLENGING
FORECAST...AND UPDATES ARE LIKELY DUE TO THE CHANGEABLE
SIGNIFICANT WEATHER EXPECTED.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...08
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1200 AM CDT Thu Oct 3 2013
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Thursday)
Issued at 301 PM CDT WED OCT 2 2013
19Z water vapor imagery shows a weak shortwave lifting east
northeast across the state. Meanwhile a closed low was digging
slowly southeast along the British Columbia coast with a trough
axis propagating around the low across northern CA and into NV.
Another closed low was moving north along the MS river causing
some scattered showers and storms over MO. At the surface a trough
of low pressure has been nearly steady state from the southern
high plains to the northern plains. Decent anticyclonic surface
flow across the southern plains and gulf coast as allowed deeper
low level moisture to surge north into NE and southeast SD.
There may be an isolated storm across Franklin or Douglas County
this afternoon due to the closed low along the MS river. However
this activity should quickly diminish with the lose of daytime
heating. The main driver for precip chances tonight looks to be an
increasing low level jet and convergence along the surface trough to
the northwest of the forecast area. Models show some increasing
isentropic lift in mid levels overnight, however the NAM and RAP do
not have much in the way of mid level moisture where the lift is
progged to occur. The higher resolution models such as the HRRR and
the RAP13 tend to keep the better lift and moisture convergence
mainly to the north of the forecast area. Because of this think the
GFS and ECMWF may be overdoing the QPF amounts over central KS and
the better chances for rain overnight is likely to be mainly over
north central KS and along the NEB state line. Overnight lows are
likely to be quite mild as decent southerly flow continues to advect
low level moisture north and keep the boundary layer mixed. This low
level moisture advection should lead to the development of low
clouds once again and limit radiational cooling. With this in mind
have lows generally in the mid and upper 60s.
For Thursday the model forecast soundings show an elevated mixed
layer advecting over the forecast area with convective inhibition
increasing for all but the far northeast corner of the forecast
area. Because of this show POPs decreasing through the day with the
chance for any overnight precip lingering across Brown CO in the
morning. Highs Thursday will be well above normal once again with
good warm air advection. Although the MAV guidance appears to be to
aggressive since solar insolation is likely to be limited through
the morning until the stratus scatters out. Forecast soundings mix
the boundary layer to 850 which would yield highs in the mid 80s.
Since the airmass doesn`t appear to change a great deal from today,
this seems reasonable and the forecast calls for highs from 84 to
87.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 301 PM CDT WED OCT 2 2013
Confidence in how Friday and Friday night will transpire remains
low. The NAM continues to be the fast solution, pushing the front
into Eastern Kansas Friday afternoon, while the GFS, ECMWF, and GEM
are several hours slower. Recent runs of the NAM, GFS, and ECMWF
have all slowed the progression of the front, and until the system
gets on shore late tonight into early Thursday, nailing down its
timing will likely continue to be hard to nail down. Have sided
with the slower solutions given the trends, which places the
western counties in the most concern. Instability is still on track
for 1000-2000 J/kg with deep-layer shear in the 30-40kt window for
severe weather potential with afternoon to early evening convection,
but still appears front will surge through quickly enough for
diminishing CAPE and shear by 06Z, though coverage should peak as this
occurs.
May see some showers linger in far eastern locations early
Saturday morning, but northwest winds and rapidly cooling low levels
will rule the day with some clouds keeping highs in 55-60 range,
around a 30-degree drop from Friday. Winds should stay up enough
Saturday night despite dewpoints falling to around 30 to keep temps
in the upper 30s and any frost in check.
Remainder of the forecast is relatively benign as northwest flow
backs slowly to southwest. There are some differences in how fast
this will happen but temps will slowly modify in a now dry lower
troposphere with northerly low level flow reaching the Gulf coast
behind the late Friday front.
&&
.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1155 PM CDT WED OCT 2 2013
Still watching thunderstorms in southern Nebraska as they may move
far enough south to impact TAF sites, but should begin to
dissipate as they approach. For now, included VCTS during most likely
time frame. Otherwise, MVFR vis may develop at MHK but should
remain VFR at TOP/FOE. Also expect an IFR stratus deck to develop
near 12Z, and while it may erode by 15Z at TOP/FOE, MHK seems to
have a good chance for maintaining ceilings through 18Z with a
gradual increase in ceiling heights through the morning. This
stratus deck will be more likely if TS does not impact TAF sites.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS TOPEKA KS
635 PM CDT Wed Oct 2 2013
...Update to near term and aviation forecast discussion...
.UPDATE...
Issued at 621 PM CDT WED OCT 2 2013
Recent high resolution model runs, specifically the last few runs
of the HRRR and the ARW/NMM models seem to be handling the ongoing
convective situation quite well over central Nebraska. WV imagery
also indicates a weak short wave trough over eastern Colorado and
moving east. Expect rather impressive isentropic ascent over north
central Kansas and south central Nebraska this evening ahead of
the weak trough and associated with the low level jet. Will also
have a fair amount of elevated instability across much of central
and eastern Kansas through the night. With all of these
ingredients coming together, expect the convective activity in
central Nebraska to continually increase in coverage this evening
with an eventual propagation to the south, perhaps focused along
the highway 81 corridor. Recent runs of the HRRR in particularly
suggest that this will take place with thunderstorms moving into
the forecast area around midnight. Would then expect the complex
to continue toward the southeast although it will likely become
less organized with southward and eastward progression into
Kansas. At this point, severe weather seems unlikely, with perhaps
a small hail or localized strong wind threat in far northern
Kansas if the system can be well organized as it progresses south.
Barjenbruch
&&
.SHORT TERM...(This Evening through Thursday)
Issued at 301 PM CDT WED OCT 2 2013
19Z water vapor imagery shows a weak shortwave lifting east
northeast across the state. Meanwhile a closed low was digging
slowly southeast along the British Columbia coast with a trough
axis propagating around the low across northern CA and into NV.
Another closed low was moving north along the MS river causing
some scattered showers and storms over MO. At the surface a trough
of low pressure has been nearly steady state from the southern
high plains to the northern plains. Decent anticyclonic surface
flow across the southern plains and gulf coast as allowed deeper
low level moisture to surge north into NE and southeast SD.
There may be an isolated storm across Franklin or Douglas County
this afternoon due to the closed low along the MS river. However
this activity should quickly diminish with the lose of daytime
heating. The main driver for precip chances tonight looks to be an
increasing low level jet and convergence along the surface trough to
the northwest of the forecast area. Models show some increasing
isentropic lift in mid levels overnight, however the NAM and RAP do
not have much in the way of mid level moisture where the lift is
progged to occur. The higher resolution models such as the HRRR and
the RAP13 tend to keep the better lift and moisture convergence
mainly to the north of the forecast area. Because of this think the
GFS and ECMWF may be overdoing the QPF amounts over central KS and
the better chances for rain overnight is likely to be mainly over
north central KS and along the NEB state line. Overnight lows are
likely to be quite mild as decent southerly flow continues to advect
low level moisture north and keep the boundary layer mixed. This low
level moisture advection should lead to the development of low
clouds once again and limit radiational cooling. With this in mind
have lows generally in the mid and upper 60s.
For Thursday the model forecast soundings show an elevated mixed
layer advecting over the forecast area with convective inhibition
increasing for all but the far northeast corner of the forecast
area. Because of this show POPs decreasing through the day with the
chance for any overnight precip lingering across Brown CO in the
morning. Highs Thursday will be well above normal once again with
good warm air advection. Although the MAV guidance appears to be to
aggressive since solar insolation is likely to be limited through
the morning until the stratus scatters out. Forecast soundings mix
the boundary layer to 850 which would yield highs in the mid 80s.
Since the airmass doesn`t appear to change a great deal from today,
this seems reasonable and the forecast calls for highs from 84 to
87.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 301 PM CDT WED OCT 2 2013
Confidence in how Friday and Friday night will transpire remains
low. The NAM continues to be the fast solution, pushing the front
into Eastern Kansas Friday afternoon, while the GFS, ECMWF, and GEM
are several hours slower. Recent runs of the NAM, GFS, and ECMWF
have all slowed the progression of the front, and until the system
gets on shore late tonight into early Thursday, nailing down its
timing will likely continue to be hard to nail down. Have sided
with the slower solutions given the trends, which places the
western counties in the most concern. Instability is still on track
for 1000-2000 J/kg with deep-layer shear in the 30-40kt window for
severe weather potential with afternoon to early evening convection,
but still appears front will surge through quickly enough for
diminishing CAPE and shear by 06Z, though coverage should peak as this
occurs.
May see some showers linger in far eastern locations early
Saturday morning, but northwest winds and rapidly cooling low levels
will rule the day with some clouds keeping highs in 55-60 range,
around a 30-degree drop from Friday. Winds should stay up enough
Saturday night despite dewpoints falling to around 30 to keep temps
in the upper 30s and any frost in check.
Remainder of the forecast is relatively benign as northwest flow
backs slowly to southwest. There are some differences in how fast
this will happen but temps will slowly modify in a now dry lower
troposphere with northerly low level flow reaching the Gulf coast
behind the late Friday front.
&&
.AVIATION...(For the 00Z TAFs through 00Z Thursday Evening)
Issued at 621 PM CDT WED OCT 2 2013
Another complicated TAF tonight. One area of emphasis is a
potential thunderstorm complex that may come out of Nebraska, and
could impact TAF sites as early as 07Z. Did not include TS at
TOP/FOE at this time as it may dissipate by the time it reaches those
sites, and MHK seems more favored. Could also see another night of
reduced vis, although persistent south winds should keep reductions
in the MVFR category. Sunrise may also bring another favorable
setup for low stratus, likely beginning at IFR but lifting to VFR
by 17Z or so. However, stratus development is highly dependent
upon overnight thunderstorm activity.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS TOPEKA KS
301 PM CDT Wed Oct 2 2013
.SHORT TERM...(This Evening through Thursday)
Issued at 301 PM CDT WED OCT 2 2013
19Z water vapor imagery shows a weak shortwave lifting east
northeast across the state. Meanwhile a closed low was digging
slowly southeast along the British Columbia coast with a trough
axis propagating around the low across northern CA and into NV.
Another closed low was moving north along the MS river causing
some scattered showers and storms over MO. At the surface a trough
of low pressure has been nearly steady state from the southern
high plains to the northern plains. Decent anticyclonic surface
flow across the southern plains and gulf coast as allowed deeper
low level moisture to surge north into NE and southeast SD.
There may be an isolated storm across Franklin or Douglas County
this afternoon due to the closed low along the MS river. However
this activity should quickly diminish with the lose of daytime
heating. The main driver for precip chances tonight looks to be an
increasing low level jet and convergence along the surface trough to
the northwest of the forecast area. Models show some increasing
isentropic lift in mid levels overnight, however the NAM and RAP do
not have much in the way of mid level moisture where the lift is
progged to occur. The higher resolution models such as the HRRR and
the RAP13 tend to keep the better lift and moisture convergence
mainly to the north of the forecast area. Because of this think the
GFS and ECMWF may be overdoing the QPF amounts over central KS and
the better chances for rain overnight is likely to be mainly over
north central KS and along the NEB state line. Overnight lows are
likely to be quite mild as decent southerly flow continues to advect
low level moisture north and keep the boundary layer mixed. This low
level moisture advection should lead to the development of low
clouds once again and limit radiational cooling. With this in mind
have lows generally in the mid and upper 60s.
For Thursday the model forecast soundings show an elevated mixed
layer advecting over the forecast area with convective inhibition
increasing for all but the far northeast corner of the forecast
area. Because of this show POPs decreasing through the day with the
chance for any overnight precip lingering across Brown CO in the
morning. Highs Thursday will be well above normal once again with
good warm air advection. Although the MAV guidance appears to be to
aggressive since solar insolation is likely to be limited through
the morning until the stratus scatters out. Forecast soundings mix
the boundary layer to 850 which would yield highs in the mid 80s.
Since the airmass doesn`t appear to change a great deal from today,
this seems reasonable and the forecast calls for highs from 84 to
87.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 301 PM CDT WED OCT 2 2013
Confidence in how Friday and Friday night will transpire remains
low. The NAM continues to be the fast solution, pushing the front
into Eastern Kansas Friday afternoon, while the GFS, ECMWF, and GEM
are several hours slower. Recent runs of the NAM, GFS, and ECMWF
have all slowed the progression of the front, and until the system
gets on shore late tonight into early Thursday, nailing down its
timing will likely continue to be hard to nail down. Have sided
with the slower solutions given the trends, which places the
western counties in the most concern. Instability is still on track
for 1000-2000 J/kg with deep-layer shear in the 30-40kt window for
severe weather potential with afternoon to early evening convection,
but still appears front will surge through quickly enough for
diminishing CAPE and shear by 06Z, though coverage should peak as this
occurs.
May see some showers linger in far eastern locations early
Saturday morning, but northwest winds and rapidly cooling low levels
will rule the day with some clouds keeping highs in 55-60 range,
around a 30-degree drop from Friday. Winds should stay up enough
Saturday night despite dewpoints falling to around 30 to keep temps
in the upper 30s and any frost in check.
Remainder of the forecast is relatively benign as northwest flow
backs slowly to southwest. There are some differences in how fast
this will happen but temps will slowly modify in a now dry lower
troposphere with northerly low level flow reaching the Gulf coast
behind the late Friday front.
&&
.AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon)
Issued at 1225 PM CDT WED OCT 2 2013
The forecast expects the MVFR conditions to continue improving as
the boundary layer continues to mix deeper. Timing of the CIGS
scattering out is based largely on the RAP13 forecast soundings.
There remains a signal for some elevated storms across north
central KS this evening. Confidence in storms affecting the
terminals is marginal as forecast soundings from the NAM and RAP
struggle to saturate the column where the strongest isentropic
lift occurs. Because of this think the MAV MOS guidance is a
little to aggressive in its POP forecast for the terminals.
Perhaps the biggest impact to aviation will be the continued
advection of low level moisture from the south. With good mixing
of the boundary layer overnight, think stratus is more likely than
ground fog, and forecast soundings from the RAP support the idea of
IFR CIGS moving back in towards midnight. My greatest confidence
is in the continued low level moisture advection so I expect the
stratus to develop in spite of the lack of low CIGS from the MOS
guidance.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1225 PM CDT Wed Oct 2 2013
.UPDATE...
Issued at 851 AM CDT WED OCT 2 2013
13Z surface obs show the warm front across Lyon and southern Osage
counties with good moisture return over the boundary. Latest
satellite suggest that low level moisture flux into northeast KS
is continuing with little sign of weakening. The 12Z RAP, and to a
lesser extent the 06Z NAM, shows the surge of low level moisture
continuing into the afternoon hours. Because of this and current
satellite trends, will need to increase cloud cover through the
day. May also need to lower highs a degree or two due to less
insolation.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 339 AM CDT WED OCT 2 2013
Currently, eastern KS remains in SW mid level flow with a weak
trough located across NE NM as well as a weak trough over the
southern MS river valley. The feature over NM is forecast to lift
northeast into central KS by this afternoon passing through our area
in the evening. At the surface a weak boundary was still present
western KS extending northeastward into SE NE. This boundary will
slowly lift northward as a trough deepens across the high plains as
a system departs the Rockies.
Low level moisture continues to advect into the area from the south.
This in combination with light winds and decent radiational cooling
has allowed patchy fog to develop. Low clouds along with additional
fog will develop in SE KS later this morning and move into the
eastern counties before sunrise. Low temperatures will drop into the
low 60s before the clouds affect the rational cooling. Fog is
expected to dissipate after 14z. Deeper moisture works into MO today
and there is a slight chance for an isolated shower in the far
southeastern counties in the afternoon. High temperatures will again
reach the mid 80s with the exception of the far southeastern
counties which may remain a few degrees cooler under the cloud cover.
Later this evening the weak mid level trough approaches from the SW
and weak isentropic lift on the 315-325 K surfaces increases over
central KS. With the increased low level moisture and continuing
height falls ML cape will increase to around 1500 j/kg through out
the day. Forecast soundings show the boundary layer cooling enough
for an inversion to form at the surface which will keep the
convection elevated. Therefore pops increase after 00z Thur as
elevated thunderstorms develop across the area overnight although
the best chances appear to be in north central KS.
.LONG TERM...(Thursday through Tuesday)
Issued at 339 AM CDT WED OCT 2 2013
Thursday and Thursday night, An intense upper level trough will dig
southeast from the great basin into the four corners region.
Southwesterly mid and upper level flow will increase across central
Rockies into the plains. As as result a lee surface low will deepen
across southeast CO and southwest KS. A surface warm front will
extend northeast across west central KS into south central NE.
There may be some isolated elevated thunderstorms during the morning
hours across the northern half the CWA but these elevated showers
and thunderstorms should dissipate through the mid morning hours. An
EML will overspread central and eastern KS, and the resulting CAP
will most likely prevent any surface based thunderstorms from
developing during the afternoon hours of Thursday within the warm
sector. South-southeasterly surface winds will increase to 15 to 25
MPH with gusts of 35 to 40 MPH through the afternoon hours. Highs
will warm into the mid 80s.
Thursday night the LLJ will increase and the deep moisture advection
will continue across eastern KS. the stronger WAA/isentropic lift
will occur across NE into IA. I cannot rule out a few isolated
elevated thunderstorm during the overnight hours across the northern
half of the CWA.
Friday and Friday night, The intense upper level trough will lift
northeast into western NE. Stronger ascent ahead of the H5 trough
will cause the lee surface low to move northeast across west
central KS into southeast NE by late afternoon. The surface cold
front will push east from western KS across central KS during the
afternoon hours. The combination of stronger surface convergence
ahead of the surface front and strong ascent ahead of the lifting H5
trough will cause scattered thunderstorms to develop ahead of the
cold front through the mid afternoon hours. An environment with
MLCAPE of 1500-2000 J/KG and 35 to 40 kts of surface to 6 KM
effective shear would allow for discrete supercell thunderstorms to
develop. If the surface and 850 MB winds remained backed then low
level SRH may be over 150 j/kg, which may pose an isolated tornado
threat for any discrete supercells. The most favored area for supercell
thunderstorms will be north central and central KS during the mid
afternoon hours. The scattered supercells thunderstorms should
congeal into QLCS or a squall line along the surface cold front.
The squall line will push east across the CWA during the evening
hours of Friday. There may be some severe wind gusts possible
within the squall line. The cold front should push east of the CWA
during the early morning hours of Saturday.
My forecast will be a composite of the ECMWF, GEM and GFS. The 00z
NAM seems to be an outlier with the H5 trough lifting out with a
positive tilt and the cold front racing east across the CWA by noon
on Friday. If the NAM turns out to be the correct model solution we
will not see severe weather Friday afternoon and may not see much in
the way of QPF.
Highs on Friday will range from the lower to mid 80s across much of
the area, though if the front is faster temperatures will be several
degrees cooler behind the front.
Saturday and Saturday night, strong low-level CAA on the back side
of the departing H5 trough will bring a much cooler airmass
southward across eastern KS. Highs will only reach the mid to upper
50s across north central KS with upper 50s and lower 60s across the
remainder of the CWA. Northwest winds of 15 to 25 MPH with higher
gusts will make it even feel cooler. Saturday night skies will clear
and winds will diminish. Low temperatures will drop into the mid to
upper 30s. I think we will remain dry enough, so that frost
formation should not occur.
Sunday through Tuesday, the upper level flow will become zonal into
next week. Highs on Sunday will warm a bit into the lower to mid
60s. Southerly surface winds Monday and Tuesday will warm highs into
the lower to mid 70s.
&&
.AVIATION...(For the 18Z TAFs through 18Z Thursday Afternoon)
Issued at 1225 PM CDT WED OCT 2 2013
The forecast expects the MVFR conditions to continue improving as
the boundary layer continues to mix deeper. Timing of the CIGS
scattering out is based largely on the RAP13 forecast soundings.
There remains a signal for some elevated storms across north
central KS this evening. Confidence in storms affecting the
terminals is marginal as forecast soundings from the NAM and RAP
struggle to saturate the column where the strongest isentropic
lift occurs. Because of this think the MAV MOS guidance is a
little to aggressive in its POP forecast for the terminals.
Perhaps the biggest impact to aviation will be the continued
advection of low level moisture from the south. With good mixing
of the boundary layer overnight, think stratus is more likely than
ground fog, and forecast soundings from the RAP support the idea of
IFR CIGS moving back in towards midnight. My greatest confidence
is in the continued low level moisture advection so I expect the
stratus to develop in spite of the lack of low CIGS from the MOS
guidance.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...Wolters
SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1235 PM EDT Wed Oct 2 2013
...Forecast Update...
Issued at 1234 PM EDT Wed Oct 2 2013
Upper low continues to drift northward across the lower MS Valley
this morning. Persistent showers have been affecting our
southwestern area...especially around Bowling Green where over an
inch of rainfall has fallen since sunrise. Shower activity is
increasing slightly in areas west of I-65...while much of the east
remains dry. Some returns are now popping up over near
Frankfort...and generally expect this activity to continue. With
this update, have generally kept the highest PoPs across the west
and southwest sections...with lesser chances over the east-central
and northeast. Temperatures are generally in the lower-middle 70s
across the west and central sections...with upper 80s across the
east where less cloud cover has been observed. Still believe that
middle to upper 70s will be possible for highs this afternoon in
most areas. Some lower 80s will be possible along and east of I-75
where less cloud cover will allow more insolation.
Update issued at 1002 AM EDT Wed Oct 2 2013
Water vapor and conventional satellite imagery show a compact upper
low drifting northward along the Mississippi River this morning.
This feature is pumping moisture up into the Ohio Valley.
Associated lift on the east side of the upper low is producing
scattered showers across the western half of the area...mainly west
of I-65. Shower activity will likely increase in coverage over the
next few hours. Highest chances of rain look to be across southern
KY...along the Cumberland/Nunn Parkway corridor across south-central
KY. Additional showers look likely in areas west of I-65 in
southern Indiana and central KY. Lesser chances of rain look good
across the far northeast/Bluegrass initially, but some scattered
showers will be possible later this afternoon.
Forecast update this morning will remove the fog wording and
increase clouds and PoPs across the south. Will also be lowering
high temperatures back into the 70s for this afternoon. If we end
up breaking out into some sun later, these temperatures may have to
be raised back up.
Update issued at 525 AM EDT Wed Oct 2 2013
Updated the forecast to insert patchy dense fog for much of southern
IN and a good portion of west central and south central KY for the
next few hours. Many ASOS and AWOS sites had visibilities that
bottomed out less than a half mile. While visibilities are
improving somewhat now with low cloud development, suspect patches
of dense fog may be present at least for the next hour or so. Thus,
issued an SPS through 7 am EDT for patchy dense fog over southern IN
and portions of west central and south central KY.
.SHORT TERM (Now through Thursday)...
Issued at 305 AM EDT Wed Oct 2 2013
First of all, will add some patchy valley fog to the forecast this
morning as it is being periodically observed at ASOS sites near
river valleys where plentiful low level moisture exists along with a
slightly more stable atmosphere.
For the rest of the day, attention will turn to an upper shortwave
trough over AR/LA/MS this morning. This upper trough will eject
northeast into the Ohio Valley today providing forcing for
convection. Moisture return ahead of this feature is apparent in WV
imagery as far north as western TN early this morning. However, a
decent cap exists over the Ohio Valley which will provide resistance
to convective develop. Thus, have sided on the slower side of model
guidance for precip arrival today. Showers/storms are expected to
blossom west of I-65 after sunrise with scattered convection slowly
developing eastward throughout the afternoon hours. With a weak
wind profile, feel that most storms would be of garden variety with
brief heavy rainfall and cloud to ground lightning the main threats.
Energy from the upper trough will push northeast through the area
tonight. Several upper level shortwaves will continue in southwest
flow mainly to our north. Therefore will keep the best POPs for
tonight confined to southern Indiana.
On the back side of the first upper level trough, a vort wave looks
to spark one last round of convection mainly Thurs morning in the
form of showers/storms. It appears that perhaps a little better
wind field and instability will available for storms. PWATs will
still be in the 1.5-1.7 inch range. Still strong storms will be
hard to come by. Should strong storms develop, though, heavy
rainfall, small hail, and gusty winds up to 40 mph will be possible.
Expect high temps to top out in the lower 80s both days with lows
tonight in the low to mid 60s.
.LONG TERM (Thursday night through Tuesday)...
Issued at 310 AM EDT Wed Oct 2 2013
The main challenge for this forecast is the timing for the
precipitation and frontal passage this weekend. For the end of the
work week, rain chances look slim as the area is under weak ridging
aloft. Went ahead and removed pops from Thursday night as any
forcing looks well to the north of the forecast area. For Friday,
moisture will be increasing and some instability looks to develop
during the afternoon. Isolated showers and thunderstorms will be
possible, but rain should not be widespread.
The models continue to differ in the timing of the frontal passage
this weekend, with the 01/12Z ECMWF much slower than the 02/00Z GFS.
With the GFS similar to previous runs and the previous forecast,
have leaned towards this solution. This would bring the front
through early Sunday morning. How fast precipitation will move out
of the eastern portions of the area is uncertain so will hold on to
slight chance pops there into early Monday. However, it is possible
the rain will move out more quickly and Monday will be dry.
With the early morning timing of the frontal passage, severe weather
does not look very likely. Instability will be low and winds are not
too strong in the lower levels. A few strong storms cannot be ruled
out, but timing is not ideal.
Temperatures will be be in the mid 80s on Friday. They will be more
of a challenge this weekend and will depend on coverage of
precipitation and how fast the front moves through. For now Saturday
looks to be in the 80s, while Sunday`s highs struggle to reach the
low 70s with Monday even cooler. Tuesday morning`s lows will dip into
the 40s, with a bit of a warm-up thereafter into midweek.
&&
.AVIATION (12Z TAF Update)...
Issued at 645 AM EDT Wed Oct 2 2013
An area of low clouds was getting close to the SDF/BWG terminals
this morning. The latest RAP brings low cigs below 500 ft into the
terminals this morning while other short term guidance like MOS/LAMP
indicate a more optimistic soln for morning clouds. Based on
satellite trends upstream, I think we`ll stay on the fringe of the
lower clouds which would put BWG/SDF/LEX in the MVFR cat at some
point this morning. However, will need to watch eastward progress
of the low clouds in case the RAP is correct.
By late morning or early afternoon, VFR conditions should prevail at
all TAF sites with scattered convection becoming common over the
area. T-storms are possible, but too isld to mention at this
point.
Winds will remain out of the SSW through the TAF period generally
below 7 kts.
Additional TAF restrictions look to arise tomorrow morning with fog
or low cigs dropping into at least the MVFR cat.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....AMS
Long Term......EER
Aviation.......AMS
AREA FORECAST DISCUSSION
NWS GRAY ME
1124 AM EDT FRI OCT 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH SATURDAY.
LOW PRESSURE WILL PULL A WARM FRONT NORTH ACROSS THE AREA LATE
SUNDAY OR SUNDAY NIGHT, WITH A TRAILING COLD FRONT TO CROSS THE
REGION MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
HAVE UPDATED GRIDS TO INCREASE POPS FURTHER FOR SOUTHERN NEW
HAMPSHIRE AND EXTREME SOUTHWEST MAINE FOR LATER THIS MORNING.
LATEST HRRR MODEL BRINGS AN AREA OF PRECIPITATION EASTWARD...FROM
ABOUT PORTLAND AND POINTS SOUTH LATER THIS MORNING AND EARLY THIS
AFTERNOON. SOME OF THIS PRECIPITATION MAY NOT REACH THE GROUND AS
A RIDGE OF HIGH PRESSURE CONTINUES TO ENTER MAINE FROM QUEBEC PROVINCE.
PREV DISC...
UPDATED FORECAST TO ADD SLGT CHC OR CHC -SHRA TO SRN MOST ZONES
PER LATEST RADAR TRENDS...OTRW NO NOTICEABLE CHANGES TO THE
PREVIOUS FORECAST.
WEAK HIGH PRES OVER THE REGION TODAY GIVES US FAIR DRY WX WITH
MILD TEMPS. THERE WILL BE SOME MID TO HIGH LVL CLOUDS AROUND DUE
TO MOISTURE ALOFT MOVING THRU WITH A WEAK UPPER LEVEL SHORT WAVE
TROF THAT HAS LIMITED SUPPORT TO PRODUCE ANY PRCP AS IT WEAKENS
WHILE MOVING THRU THE BROAD UPPER LEVEL RIDGE OVER THE EASTERN US.
AREAS OF VALLEY FOG...MAINLY ACROSS NRN AND WRN NH SHOULD LIFT
SHORTLY AFTER SUNRISE. HIGHS EXPECTED TO REACH THE 60S N AND 70 TO
75 SOUTH THOUGH A DEVELOPING ONSHORE SEA BREEZE WILL LIKELY COOL
OFF COASTAL TOWNS A BIT THIS AFTERNOON. GENERALLY USED A BLEND OF
GFS/NAM AND MET/MAV MOS GUIDANCE ALONG WITH HPC QPF.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
WEAK HIGH PRES REMAINS IN CONTROL TNGT AND SATURDAY AS THE UPPER
LEVEL RIDGE STRENGTHENS OVER THE NE AS THE WEAKENING SHORT WAVE
TROF MOVES OFF TO THE EAST. STILL SOME CLOUDS LINGER DUE TO
TRAPPED MOISTURE UNDER THE SUBSIDENCE FROM HIGH PRES PUSHING IN
FROM THE NW. THIS WILL KEEP TEMPS FROM GETTING REAL COLD TNGT...
STILL SHOULD COOL DOWN INTO THE MID 30S TO LOWER 40S N AND INTO
THE 40S TO AROUND 50 S. CLOUDS WILL LIKELY HELP HOLD OFF ANY FOG
FORMING OVERNIGHT. MORE CLOUDS AROUND ON SATURDAY DESPITE THE HIGH
OVERHEAD AS A FRONTAL BOUNDARY TO OUR S BEGINS TO PUSH N SPREADING
HIGH AND MID LVL CLOUDS NORTHWARD. SHOULD BE MILD THOUGH CLOUDS
WILL HOLD TEMPS DOWN A BIT. STILL LOOKING FOR HIGHS IN THE LOWER
TO MID 60S N AND MID 60S TO AROUND 70 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
WE BEGIN THE PERIOD WITH MILD WEATHER UNDER A SHORT WAVE RIDGE. BY
MONDAY...A SHORT WAVE TROUGH ARRIVES FROM THE GREAT LAKES AND
DRIVES A SURFACE COLD FRONT ACROSS THE FORECAST AREA. IN THE WAKE
OF THE FRONTAL PASSAGE...WE STAY A BIT UNSETTLED THROUGH LATE WEEK
AS AN UPPER TROUGH LINGERS ACROSS THE REGION.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH SATURDAY/...DESPITE LOTS OF HIGH AND MID LVL
CLOUDS TODAY WITH SOME LOWER OF CIG TNGT INTO SATURDAY IT SHOULD
BE VFR THRU THE SHORT TERM EXCEPT FOR AREAS OF VALLEY FOG THAT
WILL MOST LIKELY IMPACT LEB AND MAYBE HIE EARLY THIS MORNING.
LONG TERM...
SUN NIGHT - MON...AREAS OF MVFR IN SHOWERS.
&&
.MARINE...
SHORT TERM /TODAY THROUGH SATURDAY/...UPDATED FORECAST TO INPUT
LATEST OBSERVED DATA RESULTING IN NO NOTICEABLE CHANGES TO THE
PREVIOUS FORECAST. HIGH PRESSURE KEEPS WINDS AND SEAS WELL BELOW
SCA LEVELS THRU SATURDAY.
LONG TERM...
SUN NIGHT - MON...SMALL CRAFT WINDS AND SEAS ARE LIKELY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
839 AM EDT FRI OCT 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH SATURDAY.
LOW PRESSURE WILL PULL A WARM FRONT NORTH ACROSS THE AREA LATE
SUNDAY OR SUNDAY NIGHT, WITH A TRAILING COLD FRONT TO CROSS THE
REGION MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
HAVE UPDATED GRIDS TO INCREASE POPS FURTHER FOR SOUTHERN NEW
HAMPSHIRE AND EXTREME SOUTHWEST MAINE FOR LATER THIS MORNING.
LATEST HRRR MODEL BRINGS AN AREA OF PRECIPITATION EASTWARD...FROM
ABOUT PORTLAND AND POINTS SOUTH LATER THIS MORNING AND EARLY THIS
AFTERNOON. SOME OF THIS PRECIPITATION MAY NOT REACH THE GROUND AS
A RIDGE OF HIGH PRESSURE CONTINUES TO ENTER MAINE FROM QUEBEC PROVINCE.
PREV DISC...
UPDATED FORECAST TO ADD SLGT CHC OR CHC -SHRA TO SRN MOST ZONES
PER LATEST RADAR TRENDS...OTRW NO NOTICEABLE CHANGES TO THE
PREVIOUS FORECAST.
WEAK HIGH PRES OVER THE REGION TODAY GIVES US FAIR DRY WX WITH
MILD TEMPS. THERE WILL BE SOME MID TO HIGH LVL CLOUDS AROUND DUE
TO MOISTURE ALOFT MOVING THRU WITH A WEAK UPPER LEVEL SHORT WAVE
TROF THAT HAS LIMITED SUPPORT TO PRODUCE ANY PRCP AS IT WEAKENS
WHILE MOVING THRU THE BROAD UPPER LEVEL RIDGE OVER THE EASTERN US.
AREAS OF VALLEY FOG...MAINLY ACROSS NRN AND WRN NH SHOULD LIFT
SHORTLY AFTER SUNRISE. HIGHS EXPECTED TO REACH THE 60S N AND 70 TO
75 SOUTH THOUGH A DEVELOPING ONSHORE SEA BREEZE WILL LIKELY COOL
OFF COASTAL TOWNS A BIT THIS AFTERNOON. GENERALLY USED A BLEND OF
GFS/NAM AND MET/MAV MOS GUIDANCE ALONG WITH HPC QPF.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
WEAK HIGH PRES REMAINS IN CONTROL TNGT AND SATURDAY AS THE UPPER
LEVEL RIDGE STRENGTHENS OVER THE NE AS THE WEAKENING SHORT WAVE
TROF MOVES OFF TO THE EAST. STILL SOME CLOUDS LINGER DUE TO
TRAPPED MOISTURE UNDER THE SUBSIDENCE FROM HIGH PRES PUSHING IN
FROM THE NW. THIS WILL KEEP TEMPS FROM GETTING REAL COLD TNGT...
STILL SHOULD COOL DOWN INTO THE MID 30S TO LOWER 40S N AND INTO
THE 40S TO AROUND 50 S. CLOUDS WILL LIKELY HELP HOLD OFF ANY FOG
FORMING OVERNIGHT. MORE CLOUDS AROUND ON SATURDAY DESPITE THE HIGH
OVERHEAD AS A FRONTAL BOUNDARY TO OUR S BEGINS TO PUSH N SPREADING
HIGH AND MID LVL CLOUDS NORTHWARD. SHOULD BE MILD THOUGH CLOUDS
WILL HOLD TEMPS DOWN A BIT. STILL LOOKING FOR HIGHS IN THE LOWER
TO MID 60S N AND MID 60S TO AROUND 70 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
WE BEGIN THE PERIOD WITH MILD WEATHER UNDER A SHORT WAVE RIDGE. BY
MONDAY...A SHORT WAVE TROUGH ARRIVES FROM THE GREAT LAKES AND
DRIVES A SURFACE COLD FRONT ACROSS THE FORECAST AREA. IN THE WAKE
OF THE FRONTAL PASSAGE...WE STAY A BIT UNSETTLED THROUGH LATE WEEK
AS AN UPPER TROUGH LINGERS ACROSS THE REGION.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH SATURDAY/...DESPITE LOTS OF HIGH AND MID LVL
CLOUDS TODAY WITH SOME LOWER OF CIG TNGT INTO SATURDAY IT SHOULD
BE VFR THRU THE SHORT TERM EXCEPT FOR AREAS OF VALLEY FOG THAT
WILL MOST LIKELY IMPACT LEB AND MAYBE HIE EARLY THIS MORNING.
LONG TERM...
SUN NIGHT - MON...AREAS OF MVFR IN SHOWERS.
&&
.MARINE...
SHORT TERM /TODAY THROUGH SATURDAY/...UPDATED FORECAST TO INPUT
LATEST OBSERVED DATA RESULTING IN NO NOTICEABLE CHANGES TO THE
PREVIOUS FORECAST. HIGH PRESSURE KEEPS WINDS AND SEAS WELL BELOW
SCA LEVELS THRU SATURDAY.
LONG TERM...
SUN NIGHT - MON...SMALL CRAFT WINDS AND SEAS ARE LIKELY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
436 AM EDT THU OCT 3 2013
.SYNOPSIS...
A WARM FRONT WILL MOVE NORTH ACROSS THE REGION TODAY...THEN WEAK
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK FRONTAL BOUNDARY...DRAPED ACROSS THE REGION...WILL BE PUSHED
NORTHWARD TODAY. A SHORTWAVE TROUGH WILL MOVE ACROSS THE UPPER
OHIO VALLEY THIS AFTERNOON. THIS WAVE WILL PROVIDE CLOUDS AND THE
RISK FOR SHOWERS OR POSSIBLY A STORM...MAINLY DURING THE
AFTERNOON.
ANOTHER DAY WITH TEMPS WELL ABOVE NORMAL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
FRONT WILL BE SHIFTED NORTH OF THE AREA TONIGHT. ANOTHER UPPER
LEVEL WAVE WILL MOVE THROUGH LATE TONIGHT AND FRIDAY MORNING
PROVIDING ADDITIONAL RAIN CHANCES. IT APPEARS THE BEST LOCATIONS
TO SEE SHOWERS WILL BE ACROSS THE NORTHERN HALF OF THE FORECAST
AREA. WAVE WILL MOVE EASTWARD THURSDAY EVE...WITH RIDGE BUILDING
IN THURSDAY NIGHT.
RIDGE WILL KEEP THE AREA DRY THROUGH MUCH OF SATURDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL REMAIN AND WITH DEW POINTS
IN THE 60S IT WILL FEEL QUITE MUGGY FOR EARLY OCTOBER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
STILL TIMING AND STRENGTH DIFFERENCES IN MODEL SOLUTIONS FOR THE
PASSAGE OF THE COLD FRONT LATE THIS WEEKEND/EARLY NEXT WEEK. ONCE
FRONT CROSSES...HIGH PRESSURE WILL RETURN FOR THE REST OF THE LONG
TERM.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
WEAK FRONT SAGGING ACRS THE REGION IS EXPECTED TO POOL BNDRY LYR
MSTR AND PRVD THE FOCUS FOR SOME ST DVLPMNT BY DAYBREAK ON THU.
GIVEN THAT MDL GUIDANCE HAS NOT CAPTURED THE SCENARIO...APPARENTLY
DUE TO DIFFERENCES IN SFC RH AND ASCENT PROGS...CONFIDENCE IS NOT
HIGH...BUT SUFFICIENT TO TREND MORE PESSIMISTICALLY IN THE TAFS
FOR PORTS SURROUNDING PIT...WHERE NAM AND RAP MDLS PROJECT BNDRY
PLACEMENT BY MRNG.
FOR THU...IMPROVEMENT TO VFR IS ANTICIPATED FOR ALL PORTS...BUT
SHWR FORMATION IS ALSO EXPECTED AS SHRTWV SLIDES ACRS THE REGION.
WITH QNS OF COVERAGE AND PLACEMENT...HAVE INCLUDED VICINITY-
MENTIONS FOR TERMINALS FM PIT N...AND WWD FOR NOW.
OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE PSBL THU NGT INTO FRI AS A WRM FNT LIFTS NWD ACRS THE
AREA...WITH ADDNL RSTRNS PSBL SUN AND MON AS A CDFNT APRCHS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
106 AM EDT THU OCT 3 2013
.SYNOPSIS...
A WARM FRONT WILL MOVE NORTH ACROSS THE REGION TODAY...THEN WEAK
HIGH PRESSURE WILL BUILD IN THROUGH SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
PUSHED BACK POPS UNTIL AFTER SUNRISE AND ADJUSTED TEMPS TO LATEST
GUIDANCE.
WEAK FRONTAL BOUNDARY...DRAPED ACROSS THE REGION...WILL BE PUSHED
NORTHWARD THIS MORNING. A SHORTWAVE TROUGH WILL MOVE ACROSS THE
UPPER OHIO VALLEY THIS AFTERNOON. THIS WAVE WILL BRING CLOUDS AND
THE RISK FOR SHOWERS OR POSSIBLY A STORM.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
FRONT WILL BE SHIFTED NORTH OF THE AREA TONIGHT. ANOTHER UPPER
LEVEL WAVE WILL MOVE THROUGH LATE TONIGHT AND FRIDAY MORNING
PROVIDING ADDITIONAL RAIN CHANCES. IT APPEARS THE BEST LOCATIONS
TO SEE SHOWERS WILL BE ACROSS THE NORTHERN HALF OF THE FORECAST
AREA. WAVE WILL MOVE EASTWARD THURSDAY EVE...WITH RIDGE BUILDING
IN THURSDAY NIGHT.
RIDGE WILL KEEP THE AREA DRY THROUGH MUCH OF SATURDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL REMAIN AND WITH DEW POINTS
IN THE 60S IT WILL FEEL QUITE MUGGY FOR EARLY OCTOBER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
STILL TIMING AND STRENGTH DIFFERENCES IN MODEL SOLUTIONS FOR THE
PASSAGE OF THE COLD FRONT LATE THIS WEEKEND/EARLY NEXT WEEK. ONCE
FRONT CROSSES...HIGH PRESSURE WILL RETURN FOR THE REST OF THE LONG
TERM.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
WEAK FRONT SAGGING ACRS THE REGION IS EXPECTED TO POOL BNDRY LYR
MSTR AND PRVD THE FOCUS FOR SOME ST DVLPMNT BY DAYBREAK ON THU.
GIVEN THAT MDL GUIDANCE HAS NOT CAPTURED THE SCENARIO...APPARENTLY
DUE TO DIFFERENCES IN SFC RH AND ASCENT PROGS...CONFIDENCE IS NOT
HIGH...BUT SUFFICIENT TO TREND MORE PESSIMISTICALLY IN THE TAFS
FOR PORTS SURROUNDING PIT...WHERE NAM AND RAP MDLS PROJECT BNDRY
PLACEMENT BY MRNG.
FOR THU...IMPROVEMENT TO VFR IS ANTICIPATED FOR ALL PORTS...BUT
SHWR FORMATION IS ALSO EXPECTED AS SHRTWV SLIDES ACRS THE REGION.
WITH QNS OF COVERAGE AND PLACEMENT...HAVE INCLUDED VICINITY-
MENTIONS FOR TERMINALS FM PIT N...AND WWD FOR NOW.
OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE PSBL THU NGT INTO FRI AS A WRM FNT LIFTS NWD ACRS THE
AREA...WITH ADDNL RSTRNS PSBL SUN AND MON AS A CDFNT APRCHS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
941 PM EDT WED OCT 2 2013
.SYNOPSIS...
A WARM FRONT WILL MOVE NORTH ACROSS THE REGION THURSDAY INTO
THURSDAY NIGHT...THEN WEAK HIGH PRESSURE WILL BUILD IN THROUGH
EARLY IN THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
A WK SFC BNDRY CONTS TO DRIFT SWD ACRS THE RGN. CLDS WERE
BEGINNING TO INCR FM THE SW AHD OF AN APRCHG SHRTWV. ADDNL AREAS
OF ST ARE EXPD WITH LLVL MOISTURE POOLING ALG THE SFC BNDRY
OVRNGT. AS THE SHRTWV MOVES INTO THE OH VLY/GT LKS RGN THU...THE
BNDRY WL RTN N AS A WRMFNT. DEEPEST MOISTURE AND BEST OMEGA EXPD
TO RMN W AND N OF PIT WHERE LIKELY POPS ARE FCST. INSTBY IS EXPD
TO RMN MINIMAL SO MENTIONED ONLY ISOLD TSTM POSSIBILITY. TEMPS
SHOULD AVG ARND 10 DEG ABV SEASONAL LVLS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
THE WRMFNT WL LIFT N OUT OF THE AREA THU NGT AS THE SHRTWV PASSES
E...WITH DCRG PCPN CHCS. THE FRONT WILL BE SHUNTED NORTH OF THE
REGION FRIDAY AND MUCH OF THE AREA WILL BE IN A CAPPED WARM SECTOR
WITH SOME UPR LVL RIDGING...RESULTING IN ONLY SLIGHT-LOW CHC POPS
THROUGH SATURDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL REMAIN AND WITH DEW POINTS
IN THE 60S IT WILL FEEL QUITE MUGGY FOR EARLY OCTOBER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
STILL SEEING SOME TIMING DIFFERENCES WITH THE COLD FRONT COMING
THROUGH AT THE END OF THE WEEKEND. 12Z GFS PULLS THE FRONT THROUGH
MORE QUICKLY THAN RECENT 00Z RUNS OF THE ECMWF AND CANADIAN. ALSO
NEED TO KEEP AN EYE ON THE DEVELOPING TROPICAL SYSTEM NEAR
CUBA...ALTHOUGH 12Z GFS/00Z ECMWF SHOWS THE FRONT PASSING THE REGION
BEFORE MUCH OF THE TROPICAL MOISTURE CAN BE ABSORBED BY THE FRONT.
LATEST GFS IS ALSO A BIT OF AN OUTLIER WITH THE FRONT/LOW
INTERACTION...KEEPING THE LOW MOVING UP THE COAST SEPARATE FROM THE
FRONT AS OPPOSED TO BE ABSORBED BY THE FRONT ACROSS THE SOUTHEASTERN
UNITED STATES. WITH A LOT OF UNCERTAINTY...HAVE NOT MADE TOO MANY
CHANGES TO THIS PART OF THE FORECAST. AFTERWARDS...HIGH PRESSURE
SHOULD TAKE CONTROL OF THE WEATHER ACROSS THE EASTERN UNITED STATES.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
WEAK FRONT SAGGING ACRS THE REGION IS EXPECTED TO POOL BNDRY LYR
MSTR AND PRVD THE FOCUS FOR SOME ST DVLPMNT BY DAYBREAK ON THU.
GIVEN THAT MDL GUIDANCE HAS NOT CAPTURED THE SCENARIO...APPARENTLY
DUE TO DIFFERENCES IN SFC RH AND ASCENT PROGS...CONFIDENCE IS NOT
HIGH...BUT SUFFICIENT TO TREND MORE PESSIMISTICALLY IN THE TAFS
FOR PORTS SURROUNDING PIT...WHERE NAM AND RAP MDLS PROJECT BNDRY
PLACEMENT BY MRNG.
FOR THU...IMPROVEMENT TO VFR IS ANTICIPATED FOR ALL PORTS...BUT
SHWR FORMATION IS ALSO EXPECTED AS SHRTWV SLIDES ACRS THE REGION.
WITH QNS OF COVERAGE AND PLACEMENT...HAVE INCLUDED VICINITY-
MENTIONS FOR TERMINALS FM PIT N...AND WWD FOR NOW.
OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE PSBL THU NGT INTO FRI AS A WRM FNT LIFTS NWD ACRS THE
AREA...WITH ADDNL RSTRNS PSBL SUN AND MON AS A CDFNT APRCHS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
07/15
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
703 PM EDT WED OCT 2 2013
.SYNOPSIS...
A WARM FRONT WILL MOVE NORTH ACROSS THE REGION THURSDAY INTO
THURSDAY NIGHT...THEN WEAK HIGH PRESSURE WILL BUILD IN THROUGH
EARLY IN THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
A WK SFC BNDRY IS EXPD TO DRIFT SWD TNGT TO NR PIT BY THU MRNG.
THE BNDRY WL RTN N AS A WRMFNT AS A SHRTWV MOVES ACRS THE OH VLY
AND GT LKS RGN. DEEPEST MOISTURE AND OMEGA ARE N AND W OF PIT AND
INCRD POPS TO LIKELY IN THIS RGN...WITH POPS TAPERING OFF FURTHER
S AND E. COULD BE A TSTM BUT ONLY MINIMAL INSTBY PROGGED.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
THE WRMFNT WL LIFT N OUT OF THE AREA THU NGT AS THE SHRTWV PASSES
E...WITH DCRG PCPN CHCS. THE FRONT WILL BE SHUNTED NORTH OF THE
REGION FRIDAY AND MUCH OF THE AREA WILL BE IN A CAPPED WARM SECTOR
WITH SOME UPR LVL RIDGING...RESULTING IN ONLY SLIGHT-LOW CHC POPS
THROUGH SATURDAY.
WELL ABOVE AVERAGE TEMPERATURES WILL REMAIN AND WITH DEW POINTS
IN THE 60S IT WILL FEEL QUITE MUGGY FOR EARLY OCTOBER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
STILL SEEING SOME TIMING DIFFERENCES WITH THE COLD FRONT COMING
THROUGH AT THE END OF THE WEEKEND. 12Z GFS PULLS THE FRONT THROUGH
MORE QUICKLY THAN RECENT 00Z RUNS OF THE ECMWF AND CANADIAN. ALSO
NEED TO KEEP AN EYE ON THE DEVELOPING TROPICAL SYSTEM NEAR
CUBA...ALTHOUGH 12Z GFS/00Z ECMWF SHOWS THE FRONT PASSING THE REGION
BEFORE MUCH OF THE TROPICAL MOISTURE CAN BE ABSORBED BY THE FRONT.
LATEST GFS IS ALSO A BIT OF AN OUTLIER WITH THE FRONT/LOW
INTERACTION...KEEPING THE LOW MOVING UP THE COAST SEPARATE FROM THE
FRONT AS OPPOSED TO BE ABSORBED BY THE FRONT ACROSS THE SOUTHEASTERN
UNITED STATES. WITH A LOT OF UNCERTAINTY...HAVE NOT MADE TOO MANY
CHANGES TO THIS PART OF THE FORECAST. AFTERWARDS...HIGH PRESSURE
SHOULD TAKE CONTROL OF THE WEATHER ACROSS THE EASTERN UNITED STATES.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
RMNG CU SCTD OVR THE UPR OH REGION ARE EXPECTED TO DISSIPATE THIS
EVE AS TEMPS FALL BLO CONVECTIVE THRESHOLDS...HOWEVER...WEAK FRONT
SAGGING ACRS THE REGION IS EXPECTED TO POOL BNDRY LYR MSTR AND
PRVD THE FOCUS FOR SOME ST DVLPMNT BY DAYBREAK ON THU.
GIVEN THAT MDL GUIDANCE HAS NOT CAPTURED THE SCENARIO...APPARENTLY
DUE TO SFC DP DIFFERENCES...CONFIDENCE IS NOT HIGH...BUT SUFFICIENT
TO TREND MORE PESSIMISTICALLY IN THE TAFS FOR PORTS SURROUNDING
PIT...WHERE NAM AND RAP MDLS PROJECT BNDRY PLACEMENT BY MRNG.
FOR THU...IMPROVEMENT TO VFR IS ANTICIPATED FOR ALL PORTS...BUT
SHWR FORMATION IS ALSO EXPECTED AS SHRTWV SLIDES ACRS THE REGION.
WITH QNS OF COVERAGE AND PLACEMENT...HAVE INCLUDED VICINITY-
MENTIONS FOR TERMINALS FM PIT N...AND WWD FOR NOW.
OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RSTRNS ARE PSBL THU NGT INTO FRI AS A WRM FNT LIFTS NWD ACRS THE
AREA...WITH ADDNL RSTRNS PSBL SUN AND MON AS A CDFNT APRCHS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
07/15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
741 AM EDT FRI OCT 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 533 AM EDT FRI OCT 4 2013
TODAY...LATEST 09Z WATER VAPOR LOOP AND RUC ANALYSIS SHOW A
SHORTWAVE EXITING UPPER MI. MODELS INDICATE DNVA AND A TRANSITION TO
Q-VECT DIV IN THE WAKE OF THIS SHORTWAVE FOR THE REST OF THE
OVERNIGHT INTO MUCH OF DAY TODAY. THESE FACTORS ALONG WITH A LOSS OF
ANY MEANINGFUL WAA/ISENTROPIC ASCENT INTO AT LEAST EARLY AFTERNOON
SHOULD ALLOW ANY LINGERING SHRA TO DIE OUT TOWARD SUNRISE. ALREADY
SEEING A DIMINISHING TREND ON SHRA IN PAST HR OR TWO. EXPECT MUCH OF
TODAY TO STAY MOSTLY DRY AS MODELS INDICATE SHORTWAVE RDGG AND 5H
HEIGHT RISES OVER THE AREA IN RESPONSE TO POTENT STORM SYSTEM SLOWLY
ADVANCING FROM THE SRN/CNTRL PLAINS. THUS...HAVE DRASTICALLY TRIMMED
POPS BACK TO JUST SLIGHT CHC FOR MUCH OF THE FCST AREA. BROUGHT IN
LOW CHC (30 PCT) POPS LATE IN THE DAY ALONG THE WI BORDER AS WAA
DOES BEGIN TO INCREASE FROM THE SW.
TONIGHT...THE MODELS WERE IN REASONABLE AGREEMENT SHOWING INCREASING
300-310K ISENTROPIC ASCENT SPREADING FROM WEST TO EAST FROM LATE
EVENING INTO THE OVERNIGHT HRS TONIGHT IN RESPONSE TO CONTINUED SLOW
ADVANCE OF STORM SYSTEM THROUGH THE CENTRAL PLAINS. AS A RESULT...I
HAVE SLOWLY BROUGHT BACK LIKELY TO CATEGORICAL POPS FROM WEST TO
EAST MAINLY BETWEEN 06-12Z LATE TONIGHT. THERE MAY BE A PERIOD OF
HEAVY RAIN GIVEN THE FAVORABLE MOISTURE TRANSPORT AND PWAT VALUES TO
AROUND 1.5 INCHES. HOWEVER...CONVECTION SHOULD BE LIMITED AS BEST
MODEL MUCAPE VALUES AND NEGATIVE SHOWALTER INDICES STAY SOUTH
TONIGHT. EXPECT PCPN AMOUNTS GEENRALLY IN THE 0.20 TO 0.60 INCH
RANGE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 533 AM EDT FRI OCT 4 2013
NAM SHOWS A CLOSED 500 MB LOW OVER SD 12Z SAT WITH A RIDGE OVER THE
SERN U.S. WITH A RIDGE OVER THE WESTERN U.S. THIS CLOSED LOW WILL
CONTINUE TO MOVE SLOWLY EASTWARD THROUGH THE PERIOD THROUGH THE
UPPER GREAT LAKES. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE
WITH SOME DEEPER MOISTURE MOVING THROUGH THE CWA WITH A DRY SLOT
MOVING THROUGH ON SUNDAY. NAM SHOWS SOME ISENTROPIC LIFT AND
MOISTURE ON I300K-I315K SURFACES 12Z SAT WITH THE DRY SLOT MOVING IN
ON SUNDAY.
LOOKS LIKE A DECENT WIDESPREAD RAIN EVENT FOR THIS FORECAST PERIOD
AND WENT CATEGORICAL POPS ON SAT WITH A DRY SLOT MOVING THROUGH ON
SUN. KEPT IN SOME THUNDER CHANCES FOR SAT AND SAT NIGHT. WRAPAROUND
MOISTURE COMES INTO THE WEST ON SUN AND WENT CHANCE POPS THEN. DID
NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT RAISED LOW
TEMPERATURES SAT NIGHT A COUPLE DEGREES AS THEY LOOKED TOO COLD.
MAIN REASON IS NOT SURE THAT THE DRY SLOT WILL ALLOW CLEARING IN THE
LOWEST LEVELS FOR CLOUDS AND COLDER AIR DOES NOT ARRIVE UNTIL SUN.
IN THE EXTENDED...UPPER AIR PATTERN CONSISTS OF A 500 TROUGH OVER
THE EASTERN HALF OF THE U.S. WITH A RIDGE OVER THE ROCKIES 12Z MON.
THE RIDGE MOVES INTO THE PLAINS 12Z TUE WITH A TROUGH OVER THE
WESTERN U.S. THE TROUGH STAYS PUT 12Z WED WITH RIDGING OVER THE
GREAT LAKES REGION WHICH STAYS INTO THU. TEMPERATURES WILL CONTINUE
TO BE ABOVE NORMAL THROUGH THE PERIOD WITH UPPER RIDGING ALLOWING
DRY WEATHER TO CONTINUE. KEPT IN SLIGHT CHANCE POPS FOR MON AS UPPER
TROUGH MOVES AWAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 737 AM EDT FRI OCT 4 2013
AS SFC WARM FNT TO THE S EDGES VERY SLOWLY TOWARD UPR MI...EXPECT A
TREND FM VFR TO MVFR CIGS AT IWD AND SAW LATER THIS MORNING. THE
ARRIVAL OF MORE NMRS SHRA AT IWD AND SAW MAY CAUSE CIGS TO FALL TO
IFR LATE THIS EVENING AND OVERNIGHT RESPECTIVELY. CMX IS LIKELY TO
REMAIN VFR UNTIL PREVAILING SHRA LOWERS CIGS TO MVFR LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EDT FRI OCT 4 2013
EXPECT EAST-NORTHEAST WINDS 15 TO 25 KTS EARLY THIS MORNING TO
INCREASE TO 20 TO 30 KT WITH A FEW GALE GUSTS OVER FAR WESTERN LAKE
SUPERIOR. LOOK FOR NE WINDS WILL INCREASE TO GALES TO 35 KTS OVER
FAR WRN LAKE SUPERIOR LATE TONIGHT/EARLY SATURDAY MORNING AND THEN
CONTINUE THROUGH SATURDAY EVENING. WINDS WILL THEN DIMINISH SAT
NIGHT/SUN AS THE LOW LIFTS ACROSS THE UPPER GREAT LAKES. DEPENDING
ON THE STRENGTH OF THE SFC LOW AS IT PASSES...WILL NEED TO WATCH FOR
A PERIOD OF STRONGER NW WINDS ON THE BACKSIDE OF THE SYSTEM SUNDAY
NIGHT INTO MON. WINDS WILL BE LIGHT MON NIGHT INTO TUESDAY AS HIGH
PRESSURE MOVES OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 4 AM EDT /3 AM CDT/ SATURDAY TO 2 AM EDT /1 AM
CDT/ SUNDAY FOR LSZ162.
GALE WARNING FROM 4 AM TO 11 PM EDT SATURDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EDT FRI OCT 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 533 AM EDT FRI OCT 4 2013
TODAY...LATEST 09Z WATER VAPOR LOOP AND RUC ANALYSIS SHOW A
SHORTWAVE EXITING UPPER MI. MODELS INDICATE DNVA AND A TRANSITION TO
Q-VECT DIV IN THE WAKE OF THIS SHORTWAVE FOR THE REST OF THE
OVERNIGHT INTO MUCH OF DAY TODAY. THESE FACTORS ALONG WITH A LOSS OF
ANY MEANINGFUL WAA/ISENTROPIC ASCENT INTO AT LEAST EARLY AFTERNOON
SHOULD ALLOW ANY LINGERING SHRA TO DIE OUT TOWARD SUNRISE. ALREADY
SEEING A DIMINISHING TREND ON SHRA IN PAST HR OR TWO. EXPECT MUCH OF
TODAY TO STAY MOSTLY DRY AS MODELS INDICATE SHORTWAVE RDGG AND 5H
HEIGHT RISES OVER THE AREA IN RESPONSE TO POTENT STORM SYSTEM SLOWLY
ADVANCING FROM THE SRN/CNTRL PLAINS. THUS...HAVE DRASTICALLY TRIMMED
POPS BACK TO JUST SLIGHT CHC FOR MUCH OF THE FCST AREA. BROUGHT IN
LOW CHC (30 PCT) POPS LATE IN THE DAY ALONG THE WI BORDER AS WAA
DOES BEGIN TO INCREASE FROM THE SW.
TONIGHT...THE MODELS WERE IN REASONABLE AGREEMENT SHOWING INCREASING
300-310K ISENTROPIC ASCENT SPREADING FROM WEST TO EAST FROM LATE
EVENING INTO THE OVERNIGHT HRS TONIGHT IN RESPONSE TO CONTINUED SLOW
ADVANCE OF STORM SYSTEM THROUGH THE CENTRAL PLAINS. AS A RESULT...I
HAVE SLOWLY BROUGHT BACK LIKELY TO CATEGORICAL POPS FROM WEST TO
EAST MAINLY BETWEEN 06-12Z LATE TONIGHT. THERE MAY BE A PERIOD OF
HEAVY RAIN GIVEN THE FAVORABLE MOISTURE TRANSPORT AND PWAT VALUES TO
AROUND 1.5 INCHES. HOWEVER...CONVECTION SHOULD BE LIMITED AS BEST
MODEL MUCAPE VALUES AND NEGATIVE SHOWALTER INDICES STAY SOUTH
TONIGHT. EXPECT PCPN AMOUNTS GEENRALLY IN THE 0.20 TO 0.60 INCH
RANGE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 533 AM EDT FRI OCT 4 2013
NAM SHOWS A CLOSED 500 MB LOW OVER SD 12Z SAT WITH A RIDGE OVER THE
SERN U.S. WITH A RIDGE OVER THE WESTERN U.S. THIS CLOSED LOW WILL
CONTINUE TO MOVE SLOWLY EASTWARD THROUGH THE PERIOD THROUGH THE
UPPER GREAT LAKES. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE
WITH SOME DEEPER MOISTURE MOVING THROUGH THE CWA WITH A DRY SLOT
MOVING THROUGH ON SUNDAY. NAM SHOWS SOME ISENTROPIC LIFT AND
MOISTURE ON I300K-I315K SURFACES 12Z SAT WITH THE DRY SLOT MOVING IN
ON SUNDAY.
LOOKS LIKE A DECENT WIDESPREAD RAIN EVENT FOR THIS FORECAST PERIOD
AND WENT CATEGORICAL POPS ON SAT WITH A DRY SLOT MOVING THROUGH ON
SUN. KEPT IN SOME THUNDER CHANCES FOR SAT AND SAT NIGHT. WRAPAROUND
MOISTURE COMES INTO THE WEST ON SUN AND WENT CHANCE POPS THEN. DID
NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT RAISED LOW
TEMPERATURES SAT NIGHT A COUPLE DEGREES AS THEY LOOKED TOO COLD.
MAIN REASON IS NOT SURE THAT THE DRY SLOT WILL ALLOW CLEARING IN THE
LOWEST LEVELS FOR CLOUDS AND COLDER AIR DOES NOT ARRIVE UNTIL SUN.
IN THE EXTENDED...UPPER AIR PATTERN CONSISTS OF A 500 TROUGH OVER
THE EASTERN HALF OF THE U.S. WITH A RIDGE OVER THE ROCKIES 12Z MON.
THE RIDGE MOVES INTO THE PLAINS 12Z TUE WITH A TROUGH OVER THE
WESTERN U.S. THE TROUGH STAYS PUT 12Z WED WITH RIDGING OVER THE
GREAT LAKES REGION WHICH STAYS INTO THU. TEMPERATURES WILL CONTINUE
TO BE ABOVE NORMAL THROUGH THE PERIOD WITH UPPER RIDGING ALLOWING
DRY WEATHER TO CONTINUE. KEPT IN SLIGHT CHANCE POPS FOR MON AS UPPER
TROUGH MOVES AWAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 131 AM EDT FRI OCT 4 2013
AS SFC WARM FNT TO THE S EDGES VERY SLOWLY TOWARD UPR MI...EXPECT A
TREND FM VFR TO MVFR CIGS AT IWD. SAW HAS ALREADY SEEN CIGS LOWER TO
MVFR. THE ARRIVAL OF MORE NMRS SHRA AT IWD LATER IN THE TAF TIME MAY
CAUSE CIGS LATER THIS EVNG TO FALL TO IFR THERE. CMX IS LIKELY TO
REMAIN FAR ENUF N THAT CONDITIONS REMAIN VFR THERE THRU THE PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EDT FRI OCT 4 2013
EXPECT EAST-NORTHEAST WINDS 15 TO 25 KTS EARLY THIS MORNING TO
INCREASE TO 20 TO 30 KT WITH A FEW GALE GUSTS OVER FAR WESTERN LAKE
SUPERIOR. LOOK FOR NE WINDS WILL INCREASE TO GALES TO 35 KTS OVER
FAR WRN LAKE SUPERIOR LATE TONIGHT/EARLY SATURDAY MORNING AND THEN
CONTINUE THROUGH SATURDAY EVENING. WINDS WILL THEN DIMINISH SAT
NIGHT/SUN AS THE LOW LIFTS ACROSS THE UPPER GREAT LAKES. DEPENDING
ON THE STRENGTH OF THE SFC LOW AS IT PASSES...WILL NEED TO WATCH FOR
A PERIOD OF STRONGER NW WINDS ON THE BACKSIDE OF THE SYSTEM SUNDAY
NIGHT INTO MON. WINDS WILL BE LIGHT MON NIGHT INTO TUESDAY AS HIGH
PRESSURE MOVES OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 4 AM EDT /3 AM CDT/ SATURDAY TO 2 AM EDT /1 AM
CDT/ SUNDAY FOR LSZ162.
GALE WARNING FROM 4 AM TO 11 PM EDT SATURDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...KC
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
139 AM EDT FRI OCT 4 2013
.UPDATE...
ISSUED AT 831 PM EDT THU OCT 3 2013
LATEST SHORTER TERM NUMERICAL MODELS HAVE A POOR HANDLE ON AREA OF
SHRA MOVING NEWD INTO UPR MI FM WI IN ASSOCIATION WITH SHRTWV LIFTING
NEWD THRU NW WI PER LATEST WV IMAGERY. OPTED TO BUMP UP POPS THRU
LATE EVNG FOR MUCH OF THE CWA PER THE LATEST RUC FCST FAIRLY VIGOROUS
H7-3 QVECTOR CNVGC/UPR DVGC AHEAD OF THIS SHRTWV. STILL EXPECT THE
SHRA TO DIMINISH WITH TIME AS THE RUC SHOWS AREA OF QVECTOR CNVGC/UPR
DVGC WEAKENING BY 06Z AS THE PRECIP AREA RUNS INTO DRIER AIR TO THE
NE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 452 PM EDT THU OCT 3 2013
THE SHORT TERM WILL BE DOMINATED BY STRENGTHENING LOW PRESSURE OVER
THE PLAINS AS A 500MB LOW OVER ID MOVES TO WRN NE BY 00Z SAT. AT THE
SFC...THERE IS CURRENTLY A LOW LEEWARD OF THE CO ROCKIES...WITH A
SFC TROUGH/WARM FRONT EXTENDING INTO SRN WI AND LOWER MI. SHOWERS
AND THUNDERSTORMS HAVE BEEN MOVING ALONG THE SFC WARM FRONT
TODAY...WHILE PRECIP LAST NIGHT MOVED PRIMARILY ALONG THE 850MB WARM
FRONT/TROUGH THAT EXTENDS OVER THE CWA. ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE FORMED ALONG THE FROM...BUT MOISTURE TRANSPORT
WILL BE BEST OVER FAR WRN LAKE SUPERIOR DUE TO BLOCKING OF MOISTURE
TRANSPORT OVER THE REST OF THE CWA BY PRECIP TO THE S. THINK THE
CURRENT PRECIP OVER SRN/CENTRAL WI WILL STAY FOCUSED ALONG THE SFC
WARM FRONT AND STAY TO THE S...MAYBE BRUSHING THE SCENTRAL CWA.
VERY TRICKY FORECAST THROUGH 00Z SAT AS MODELS ARE HAVING A HARD
TIME WITH THE CURRENT AND FORECAST CONVECTION. THE WARM FRONTS WILL
STAY NEARLY STATIONARY...WITH CONVECTION FIRING ALONG THE SFC WARM
FRONT TO THE S AS THE LLJ KICKS IN. THIS CONVECTION SHOULD BLOCK
MOISTURE TRANSPORT INTO MUCH OF THE CWA TONIGHT...KEEPING PRECIP
SUPPRESSED ALONG THE 850MB WARM FRONT. MODELS GENERALLY AGREE WITH
THIS IN SHOWING EITHER NO TO VERY LITTLE PRECIP TONIGHT...OR A QUICK
MOVING BAND OF PRECIP THAT MAY MOVE ACROSS THE CWA.
WITH THE SFC LOW DEEPENING TO AROUND 1000MB AS IT MOVES TO FAR ERN
NE BY 00Z SAT...THE WARM FRONT WILL MOVE SLIGHTLY N/NW. THINK THAT
BEST CHANCES FOR PRECIP WILL BE OVER THE WRN CWA CLOSER TO THE 850MB
WARM FRONT WHERE THE BEST MOISTURE TRANSPORT IS LOCATED. STILL
FAIRLY UNCERTAIN WITH PRECIP PLACEMENT GIVEN MODEL DISAGREEMENT...SO
BROAD BRUSHED POPS. NE WINDS PICK UP /ESPECIALLY OVER THE GREAT
LAKES/ FRI AFTERNOON/EVENING AS THE PRESSURE GRADIENT OVER THE
REGION INCREASES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 452 PM EDT THU OCT 3 2013
FRIDAY NIGHT...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE MID
LEVEL LOW MOVING INTO SE SD AND THE SFC LOW/TROUGH INTO SRN MN BY
12Z/SAT. CATEGORICAL PCPN CHANCES LOOK ON TRACK FRIDAY NIGHT WITH
300K-310K ISENTROPIC ALONG AND NORTH OF THE 850 MB WARM FRONT
BRINGING WIDESPREAD RAIN THROUGH UPPER MI. ALTHOUGH THEIR MAY BE A
PERIOD OF HEAVY RAIN GIVEN THE FAVORABLE MOISTURE TRANSPORT AND PWAT
VALUES TO AROUND 1.5 INCHES...THE AREA OF STRONGEST OF LIFT IS
EXPECTED TO MAKE STEADY PROGRESS TO THE NNE. CONVECTION SHOULD ALSO
BE LIMITED WITH FCST MUCAPE VALUES ONLY TO AROUND 400 J/KG OVER THE
SRN PORTION OF THE CWA. PCPN AMOUNTS IN THE 0.50 TO 0.75 INCH RANGE
ARE EXPECTED.
SAT INTO SAT NIGHT...THE MODELS BEGIN TO DIVERGE WITH THE
GFS/GEFS/GEM/UKMET REMAINING FASTER WITH THE MID/SFC LOW MOVEMENT
COMPARED TO THE ECMWF. UNCERTAINTY IS GREATER...BUT THE FCST WAS
TRENDED MORE TOWARD THE GFS/GEM/UKMET. ALTHOUGH THE MORE WIDESPREAD
PCPN IS EXPECTED TO DEPART EARLY...LIKELY POPS REMAIN THROUGH THE
DAY WITH 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL LOW
SUPPORTED SCT/NMRS SHRA AND A FEW ELEVATED TSRA IN THE 850 MB WARM
SECTOR...ESPECIALLY OVER THE WEST. PCPN CHANCES WILL DIMINISH
SATURDAY NIGHT AS THE DRY SLOT MOVES INTO THE AREA.
SUN INTO MON...EXPECT SOME -SHRA TO LINGER WITH DEFORMATION/COMMA HEAD
MOISTURE/PCPN WRAPPING AROUND THE BACKSIDE OF MID LEVEL LOW. LOW
LEVEL CYCLONIC FLOW AND 850MB TEMPS FALLING TO -2C TO 2C ALSO
SUGGEST POTENTIAL OF SCT LAKE ENHANCED -SHRA BEHIND THE SYSTEM FOR
LOCATIONS FAVORED BY WNW FLOW. ALTHOUGH THE DEEPER MOISTURE AND
ASSOCIATED PCPN CHANCES WITH THE STORM SYSTEM MOVE OUT SUN NIGHT
WITH THE FASTER GFS/GEM/UKMET...LOWER END PCPN CHANCES LINGER INTO
MON OVER MAINLY THE NORTH WITH THE POSSIBILITY OF A TRAILING CLIPPER
SHORTWAVE BRUSHING THE AREA.
DRY WEATHER WILL THEN FOLLOW TUE THROUGH THU AS A TROF DEEPENING
OVER THE ROCKIES/WRN PLAINS ALLOWS A BROAD MID-LVL RIDGE TO BUILD
INTO THE GREAT LAKES REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 131 AM EDT FRI OCT 4 2013
AS SFC WARM FNT TO THE S EDGES VERY SLOWLY TOWARD UPR MI...EXPECT A
TREND FM VFR TO MVFR CIGS AT IWD. SAW HAS ALREADY SEEN CIGS LOWER TO
MVFR. THE ARRIVAL OF MORE NMRS SHRA AT IWD LATER IN THE TAF TIME MAY
CAUSE CIGS LATER THIS EVNG TO FALL TO IFR THERE. CMX IS LIKELY TO
REMAIN FAR ENUF N THAT CONDITIONS REMAIN VFR THERE THRU THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 452 PM EDT THU OCT 3 2013
GENERALLY LIGHT EAST-NORTHEAST WINDS AHEAD OF AN APPROACHING WARM
FRONT WILL INCREASE TO 15 TO 25 KTS LATE TODAY AND TONIGHT...WITH
THE HIGHEST GUSTS ACROSS WESTERN LAKE SUPERIOR. WINDS WILL INCREASE
FURTHER TO 20-30 KTS FRI THRU SAT AS SFC LOW PRES SLOWLY LIFTS
TOWARD THE UPPER GREAT LAKES. A BRIEF PERIOD OF GALES TO 35 KTS MAY
OCCUR FRI NIGHT AND EARLY SAT MORNING OVER WRN LAKE SUPERIOR. WINDS
WILL THEN DIMINISH SAT NIGHT/SUN AS THE LOW LIFTS ACROSS THE UPPER
GREAT LAKES. DEPENDING ON THE STRENGTH OF THE SFC LOW AS IT
PASSES...WILL NEED TO WATCH FOR A PERIOD OF STRONGER WINDS ON THE
BACKSIDE OF THE SYSTEM LATER SUN INTO EARLY MON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR LSZ162-
263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
832 PM EDT THU OCT 3 2013
.UPDATE...
ISSUED AT 831 PM EDT THU OCT 3 2013
LATEST SHORTER TERM NUMERICAL MODELS HAVE A POOR HANDLE ON AREA OF
SHRA MOVING NEWD INTO UPR MI FM WI IN ASSOCIATION WITH SHRTWV LIFTING
NEWD THRU NW WI PER LATEST WV IMAGERY. OPTED TO BUMP UP POPS THRU
LATE EVNG FOR MUCH OF THE CWA PER THE LATEST RUC FCST FAIRLY VIGOROUS
H7-3 QVECTOR CNVGC/UPR DVGC AHEAD OF THIS SHRTWV. STILL EXPECT THE
SHRA TO DIMINISH WITH TIME AS THE RUC SHOWS AREA OF QVECTOR CNVGC/UPR
DVGC WEAKENING BY 06Z AS THE PRECIP AREA RUNS INTO DRIER AIR TO THE
NE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 452 PM EDT THU OCT 3 2013
THE SHORT TERM WILL BE DOMINATED BY STRENGTHENING LOW PRESSURE OVER
THE PLAINS AS A 500MB LOW OVER ID MOVES TO WRN NE BY 00Z SAT. AT THE
SFC...THERE IS CURRENTLY A LOW LEEWARD OF THE CO ROCKIES...WITH A
SFC TROUGH/WARM FRONT EXTENDING INTO SRN WI AND LOWER MI. SHOWERS
AND THUNDERSTORMS HAVE BEEN MOVING ALONG THE SFC WARM FRONT
TODAY...WHILE PRECIP LAST NIGHT MOVED PRIMARILY ALONG THE 850MB WARM
FRONT/TROUGH THAT EXTENDS OVER THE CWA. ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE FORMED ALONG THE FROM...BUT MOISTURE TRANSPORT
WILL BE BEST OVER FAR WRN LAKE SUPERIOR DUE TO BLOCKING OF MOISTURE
TRANSPORT OVER THE REST OF THE CWA BY PRECIP TO THE S. THINK THE
CURRENT PRECIP OVER SRN/CENTRAL WI WILL STAY FOCUSED ALONG THE SFC
WARM FRONT AND STAY TO THE S...MAYBE BRUSHING THE SCENTRAL CWA.
VERY TRICKY FORECAST THROUGH 00Z SAT AS MODELS ARE HAVING A HARD
TIME WITH THE CURRENT AND FORECAST CONVECTION. THE WARM FRONTS WILL
STAY NEARLY STATIONARY...WITH CONVECTION FIRING ALONG THE SFC WARM
FRONT TO THE S AS THE LLJ KICKS IN. THIS CONVECTION SHOULD BLOCK
MOISTURE TRANSPORT INTO MUCH OF THE CWA TONIGHT...KEEPING PRECIP
SUPPRESSED ALONG THE 850MB WARM FRONT. MODELS GENERALLY AGREE WITH
THIS IN SHOWING EITHER NO TO VERY LITTLE PRECIP TONIGHT...OR A QUICK
MOVING BAND OF PRECIP THAT MAY MOVE ACROSS THE CWA.
WITH THE SFC LOW DEEPENING TO AROUND 1000MB AS IT MOVES TO FAR ERN
NE BY 00Z SAT...THE WARM FRONT WILL MOVE SLIGHTLY N/NW. THINK THAT
BEST CHANCES FOR PRECIP WILL BE OVER THE WRN CWA CLOSER TO THE 850MB
WARM FRONT WHERE THE BEST MOISTURE TRANSPORT IS LOCATED. STILL
FAIRLY UNCERTAIN WITH PRECIP PLACEMENT GIVEN MODEL DISAGREEMENT...SO
BROAD BRUSHED POPS. NE WINDS PICK UP /ESPECIALLY OVER THE GREAT
LAKES/ FRI AFTERNOON/EVENING AS THE PRESSURE GRADIENT OVER THE
REGION INCREASES.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 452 PM EDT THU OCT 3 2013
FRIDAY NIGHT...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE MID
LEVEL LOW MOVING INTO SE SD AND THE SFC LOW/TROUGH INTO SRN MN BY
12Z/SAT. CATEGORICAL PCPN CHANCES LOOK ON TRACK FRIDAY NIGHT WITH
300K-310K ISENTROPIC ALONG AND NORTH OF THE 850 MB WARM FRONT
BRINGING WIDESPREAD RAIN THROUGH UPPER MI. ALTHOUGH THEIR MAY BE A
PERIOD OF HEAVY RAIN GIVEN THE FAVORABLE MOISTURE TRANSPORT AND PWAT
VALUES TO AROUND 1.5 INCHES...THE AREA OF STRONGEST OF LIFT IS
EXPECTED TO MAKE STEADY PROGRESS TO THE NNE. CONVECTION SHOULD ALSO
BE LIMITED WITH FCST MUCAPE VALUES ONLY TO AROUND 400 J/KG OVER THE
SRN PORTION OF THE CWA. PCPN AMOUNTS IN THE 0.50 TO 0.75 INCH RANGE
ARE EXPECTED.
SAT INTO SAT NIGHT...THE MODELS BEGIN TO DIVERGE WITH THE
GFS/GEFS/GEM/UKMET REMAINING FASTER WITH THE MID/SFC LOW MOVEMENT
COMPARED TO THE ECMWF. UNCERTAINTY IS GREATER...BUT THE FCST WAS
TRENDED MORE TOWARD THE GFS/GEM/UKMET. ALTHOUGH THE MORE WIDESPREAD
PCPN IS EXPECTED TO DEPART EARLY...LIKELY POPS REMAIN THROUGH THE
DAY WITH 700-300 MB QVECTOR CONV AHEAD OF THE MID LEVEL LOW
SUPPORTED SCT/NMRS SHRA AND A FEW ELEVATED TSRA IN THE 850 MB WARM
SECTOR...ESPECIALLY OVER THE WEST. PCPN CHANCES WILL DIMINISH
SATURDAY NIGHT AS THE DRY SLOT MOVES INTO THE AREA.
SUN INTO MON...EXPECT SOME -SHRA TO LINGER WITH DEFORMATION/COMMA HEAD
MOISTURE/PCPN WRAPPING AROUND THE BACKSIDE OF MID LEVEL LOW. LOW
LEVEL CYCLONIC FLOW AND 850MB TEMPS FALLING TO -2C TO 2C ALSO
SUGGEST POTENTIAL OF SCT LAKE ENHANCED -SHRA BEHIND THE SYSTEM FOR
LOCATIONS FAVORED BY WNW FLOW. ALTHOUGH THE DEEPER MOISTURE AND
ASSOCIATED PCPN CHANCES WITH THE STORM SYSTEM MOVE OUT SUN NIGHT
WITH THE FASTER GFS/GEM/UKMET...LOWER END PCPN CHANCES LINGER INTO
MON OVER MAINLY THE NORTH WITH THE POSSIBILITY OF A TRAILING CLIPPER
SHORTWAVE BRUSHING THE AREA.
DRY WEATHER WILL THEN FOLLOW TUE THROUGH THU AS A TROF DEEPENING
OVER THE ROCKIES/WRN PLAINS ALLOWS A BROAD MID-LVL RIDGE TO BUILD
INTO THE GREAT LAKES REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 726 PM EDT THU OCT 3 2013
DESPITE UPSLOPE E-NE FLOW...PRESENCE OF DRY LLVL AIR WL SLOW DOWN
TRANSITION FM PREDOMINANT VFR TO MVFR CIGS UNTIL LATE TNGT/FRI MRNG.
THE TREND TOWARD LOWERING CIGS WL CONT ON FRI AS SFC WARM FNT APRCHS
SLOWLY FM THE S. THESE LOWER IFR CIGS MAY NOT REACH THE FARTHER N
CMX LOCATION UNTIL AFTER 05/00Z.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 452 PM EDT THU OCT 3 2013
GENERALLY LIGHT EAST-NORTHEAST WINDS AHEAD OF AN APPROACHING WARM
FRONT WILL INCREASE TO 15 TO 25 KTS LATE TODAY AND TONIGHT...WITH
THE HIGHEST GUSTS ACROSS WESTERN LAKE SUPERIOR. WINDS WILL INCREASE
FURTHER TO 20-30 KTS FRI THRU SAT AS SFC LOW PRES SLOWLY LIFTS
TOWARD THE UPPER GREAT LAKES. A BRIEF PERIOD OF GALES TO 35 KTS MAY
OCCUR FRI NIGHT AND EARLY SAT MORNING OVER WRN LAKE SUPERIOR. WINDS
WILL THEN DIMINISH SAT NIGHT/SUN AS THE LOW LIFTS ACROSS THE UPPER
GREAT LAKES. DEPENDING ON THE STRENGTH OF THE SFC LOW AS IT
PASSES...WILL NEED TO WATCH FOR A PERIOD OF STRONGER WINDS ON THE
BACKSIDE OF THE SYSTEM LATER SUN INTO EARLY MON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING FOR
LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
828 PM EDT THU OCT 3 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 356 PM EDT THU OCT 3 2013
A FEW ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE MOVING ACROSS
LOWER MICHIGAN THROUGH SATURDAY. A WARM FRONT WILL FOCUS THE
STORMS TONIGHT INTO FRIDAY...THEN A COLD FRONT WILL BRING A FINAL
ROUND OF STORMS SATURDAY INTO SATURDAY NIGHT. SOME HEAVY RAIN IS
POSSIBLE WITH THE STORMS. HIGH WINDS ARE POSSIBLE SATURDAY NIGHT
INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 828 PM EDT THU OCT 3 2013
WE HAVE FRESHENED UP THE FORECAST THIS EVENING TO DELAY THE ONSET
OF THE HIGHER RAIN CHANCES FOR A FEW HOURS.
RADAR IMAGERY AS OF 0015Z SHOWS SOME SCATTERED SHOWERS AND STORMS
UP ACROSS THE NE CORNER OF THE CWFA. ALSO...A DYING LINE OF
SHOWERS IS COMING INTO THE SW CORNER THAT WAS A MORE POTENT STORM
EARLIER ACROSS CHICAGO. THE LINE DYING OUT DOWN SOUTH IS
OUTRUNNING BETTER INSTABILITY SW OF THE CWFA.
WE STILL EXPECT ACTIVITY TO INCREASE IN COVERAGE TONIGHT AS A 20+
KNOT LOW LEVEL JET JUST SOUTH OF I-94 WILL STRENGTHEN TO AROUND 30
KNOTS AND HELP INCREASE THE MOISTURE TRANSPORT AND CONVERGENCE
ACROSS THE AREA. THIS SHOULD BEGIN BY 06Z AND THEN MOVE OUT AROUND
12Z. INSTABILITY IS NOT EXPECTED TO BE THAT STRONG WITH ELEVATED
LI/S AROUND -2 TO -3C...AND MORE STABLE AT THE SFC.
LOCALLY HEAVY RAINFALL IS LIKELY THE BIGGEST THREAT...AND WE ARE
NOT CONFIDENT ANY PLACE WILL ACTUALLY SEE FLOODING. WE WILL
MONITOR RADAR TRENDS OVERNIGHT FOR ANY TRAINING OF RAINFALL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 356 PM EDT THU OCT 3 2013
FORECAST CONCERNS IN THE NEAR TERM ARE FOR TIMING ROUNDS OF
CONVECTION...AND FOR FLOOD AND HIGH WIND THREATS WITH THE
APPROACHING LOW. HEAVY RAIN THREAT EXISTS TONIGHT THROUGH SATURDAY
NIGHT WITH ISOLATED FLOODING POSSIBLE GIVEN DEEP MOISTURE
...ALTHOUGH STORM MOVEMENT SHOULD BE QUICK ENOUGH TO PRECLUDE
EXCESSIVE AMOUNTS.FIRST BATCH OF RAIN IS COMING THROUGH ATTM AND
IS RELATIVELY LIGHT EXCEPT FOR A FEW DEEPER UPDRAFTS. PRECIP
EFFICIENCY SHOULD REMAIN HIGH INTO THE WEEKEND SO WE WILL HAVE TO
CLOSELY WATCH RAINFALL RATES WITH ANY DEEP CONVECTION.
THE 12Z GFS AND NAM CONTINUE FASTER WITH THE STORM THAN THE EURO
AS THEY EJECT THE MID LEVEL CLOSED LOW FASTER TO THE NORTHWEST.
DESPITE TIMING ISSUES...ONE THING LOOKS LIKE A GOOD BET WITH THIS
SYSTEM AND THAT IS A VERY STRONG WIND FIELD...BRINGING THE
POSSIBILITY OF A SYNOPTIC HIGH WIND THREAT SATURDAY NIGHT OR
SUNDAY MORNING. SEVERE THREAT APPEARS TO BE LOWERED BY THE NIGHT
TIME PASSAGE OF THE CONVECTION ALONG THE COLD FRONT. EVEN SO THE
CONVECTION IN THE WARM CONVEYOR BELT COULD TAKE ON A SERIAL
DERECHO STRUCTURE AND BRING SOME STRONG WINDS AND HEAVY RAINS.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 356 PM EDT THU OCT 3 2013
WITH THE COLD FRONT THROUGH COOLER WEATHER WILL MOVE IN FOR THE
FIRST PART OF NEXT WEEK. TRENDED POPS DOWNWARD FOR SUNDAY AND
SUNDAY NIGHT AS WE MAY BE DRY SLOTTED FOR MUCH THIS TIME FRAME. BUT
WITH THE UPPER TROUGH NOT PASSING THROUGH UNTIL SUNDAY EVENING...
BELIEVE LOW CHANCE POPS ARE STILL WARRANTED. ALSO TRENDED TEMPS
DOWN FOR SUNDAY/SUNDAY NIGHT AS CONFIDENCE IS GROWING THAT THE FRONT
WILL BE WELL EAST OF OUR AREA BY THEN.
TEMPS WILL DIP TO NEAR NORMAL VALUES FOR THE FIRST PART OF THE WORK
WEEK. BUT THEN SOLID WARM ADVECTION AND UPPER RIDGING IS INDICATED
OVER THE EASTERN U.S. BY TUESDAY NIGHT. THIS SHOULD LEAD TO FAIR
WEATHER AND ABOVE NORMAL TEMPS IN THE 70S BY WED/THU. ONE
CAVEAT...WE WILL HAVE TO MONITOR HOW THE REMNANTS OF KAREN MOVE
THROUGH THE FIRST PART OF NEXT WEEK. AS OF NOW THE MODEL TAKE IT
EAST OF THE APPALACHIANS. HOWEVER...IF THE UPPER RIDGE IS DELAYED
THIS SYSTEM COULD MOVE CLOSER TO THE GREAT LAKES IN THE TUE/WED TIME
FRAME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 750 PM EDT THU OCT 3 2013
THE SHORT STORY IS I EXPECT VFR CONDITIONS EARLY THIS EVENING...
GOING IFR WITH SHOWERS AND ISOLATED THUNDERSTORMS (LOCALLY HEAVY
RAINFALL) BETWEEN 04Z AND 09Z. AFTER THE SHOWERS MOVE OUT I THEN
EXPECT A PERIOD OF DENSE FOG (LIFR) FROM 11Z-15Z. BY 16-18Z IT
SHOULD BECOME VFR AT ALL TAF SITES.
THE LOW CLOUDS ARE BREAKING UP AS I WRITE THIS. I EXPECT ALL TAF
SITES TO BE VFR BY 01Z. HOWEVER...THAT WILL NOT LAST FOR LONG. THE
UPSTREAM SHORTWAVE (SEEN NICELY ON WATER VAPOR LOOPS) HAS AN AREA
OF THUNDERSTORMS AHEAD OF IT (DBQ TO BMI TO SPI) AT 2335Z. BASED
ON THE RAP AND HRRR MODELS...THAT AREA OF SHOWERS/THUNDERSTORMS WILL
CROSS OUR CWA BETWEEN 04Z AND 09Z. THE INSTABILITY IS MARGINAL AND
BEING AT NIGHT AND WITH A DEEP WARM LAYER... IT IS QUESTIONABLE HOW
MUCH THUNDER THERE WOULD REALLY BE WITH THESE SHOWERS...MOSTLY
THESE WILL BE RAIN SHOWERS. THERE COULD BE SOME HEAVY SHOWERS AND
WE WILL HAVE TO WATCH THAT CLOSELY. IN ANY EVENT... THAT WILL
BRING IFR CIGS/VSBY TO ALL OF THE TAF SITES BETWEEN 06Z AND 09Z.
SURFACE WIND WILL BE LIGHT...WHICH WILL ALLOW THE VISIBILITY TO BE
LOWER THANT IT OTHERWISE WOULD BE.
ONCE THAT SYSTEM MOVES EAST OF THE AREA AFTER 09Z OR SO THE MID
AND HIGH CLOUD SHOULD CLEAR. THAT WILL ALLOW DENSE FOG TO DEVELOP
AT MOST OF THE TAF SITES BY 10Z- 12Z. BEING THAT IT IS EARLY
OCTOBER THE FOG WILL NOT BE QUICK TO BURN OFF (SURFACE WINDS
STAYING LIGHT WILL HELP TO KEEP THE FOG IN PLACE). IT MAY TAKE
TILL 16Z FOR THE FOG TO BURN OFF. ALSO WITH THE FRONT IN THE
AREA... WE MAY SEE ADDITIONAL PERIODS OF SHOWERS BUT TO KEEP THE
TAFS AS SIMPLE AS POSSIBLE I DID NOT PUT SHOWERS IN THE TAFS FOR
FRIDAY. IF THE SHOWERS DO NOT MOVE INTO THE AREA I WOULD EXPECT
VFR CONDITIONS BEING SOUTH OF THE WARM FRONT FRIDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 356 PM EDT THU OCT 3 2013
WINDS AND WAVES WILL BE ON THE INCREASE FRIDAY AND ESPECIALLY
SATURDAY. A SMALL CRAFT ADVISORY WILL BE NEEDED BY FRIDAY NIGHT
AND A GALE WARNING MAY BE NEEDED BY SATURDAY OR SATURDAY NIGHT.
&&
.HYDROLOGY...
ISSUED AT 356 PM EDT THU OCT 3 2013
DEEP MOISTURE WILL BE IN PLACE THROUGH SATURDAY WITH HEAVY RAIN
POSSIBLE. EXPECT RAINFALL TOTALS TO BE CLOSE TO AN INCH OR NORTH
OF THE GRAND RIVER BASIN FROM TONIGHT THROUGH SATURDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...NJJ
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...JK
AVIATION...WDM
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
709 PM EDT WED OCT 2 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 319 PM EDT WED OCT 2 2013
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE OVERNIGHT AND
PERSIST THROUGH THE WEEKEND. MONDAY AND TUESDAY WILL BE DRY AND
COOL...WITH WARMER TEMPERATURES ARRIVING WEDNESDAY.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY NIGHT)
ISSUED AT 319 PM EDT WED OCT 2 2013
THE MAIN CONCERN IS TIMING PRECIPITATION OVERNIGHT. WE ADJUSTED THE
FORECAST TO A SLIGHTLY LATER ONSET. PRECIPITATION SHOULD BEGIN OVER
FAR SOUTHWEST LOWER MICHIGAN SHORTLY AFTER MIDNIGHT AND THEN
SPREAD NORTHEAST TO THE I-96 CORRIDOR BY LATE MORNING. CONFIDENCE IN
TIMING IS RELATIVELY GOOD DUE TO GOOD AGREEMENT AMONG THE CONVECTION
ALLOWING MODELS. AGREE WITH THE SPC OUTLOOKS THAT THE THREAT FOR
THUNDERSTORMS WILL SPREAD NORTH OF I-96 AFTER 8 AM THURSDAY.
THE REST OF THE PERIOD LOOKS UNSETTLED AS A SURFACE BOUNDARY
CURRENTLY EXTENDING FROM NORTHERN ILLINOIS THROUGH NORTHWEST OHIO
LIFTS NORTH INTO LOWER MICHIGAN...POSSIBLY SHIFTING THE BEST FOCUS
FOR PRECIPITATION TOWARDS NORTHERN LOWER MICHIGAN THURSDAY NIGHT AND
FRIDAY.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 319 PM EDT WED OCT 2 2013
THE WEEKEND FRONT CONTINUES TO LOOK SLOWER...PROBABLY NOT CROSSING
SW MI UNTIL SUNDAY MORNING. THIS IS NOT SURPRISING GIVEN THE
AMPLIFIED UPPER PATTERN. WITH THIS DELAY IN MIND...TWEAKED TEMPS UP
SLIGHTLY FOR SAT THROUGH SUN. ALSO TWEAKED POPS...MAINLY OVER THE
SOUTHERN CWA...LOWERING POPS FOR SAT AND RAISING THEM FOR SAT NIGHT
GIVEN THE SLOWER TIMING. THE LATEST RUNS SHOW THE SHARP H8 TEMP
DROP IS NOT AS SEVERE AS PREVIOUS RUNS...ONLY GOING FROM AROUND +15C
SATURDAY TO AROUND +6C BY SUNDAY NIGHT. GIVEN THIS...AND IF THE
FRONT ARRIVES IN THE MORNING HOURS...SEVERE STORMS SEEM LESS LIKELY.
THE THUNDER THREAT SHOULD END AS THE FRONT COMES THROUGH EARLY
SUNDAY...HOWEVER RAIN SHOWERS SHOULD PERSIST THROUGH SUNDAY NIGHT AS
AN UPPER LOW TRACKS ACROSS THE NORTHERN GREAT LAKES.
DRIER WEATHER IS EXPECTED AS WE GET INTO THE FIRST PART OF THE NEXT
WORK WEEK. ZONAL FLOW AND HIGH PRESSURE OVER THE TN VALLEY SHOULD
BRING IN THE FAIR WEATHER. THE WORK WEEK SHOULD START CHILLY WITH
HIGHS AROUND 60...BUT RETURN FLOW KICKS IN BY TUESDAY NIGHT/WED...
WITH HIGHS OF 70 TO 75 EXPECTED BY WED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 710 PM EDT WED OCT 2 2013
THERE ARE TWO MAIN ISSUES TONIGHT... FIRST IS WILL THERE BE ANY
RAIN (THUNDERSTORMS) WITH THE WARM FRONT MOVING THROUGH THE TAF SITES
THURSDAY OVER THE GRR TAF SITES? THE OTHER QUESTION IS JUST HOW
LOW DOES THE CEILING/VSBY GET THURSDAY AS THE WARMER AND MORE
MOIST AIR RETURNS?
CURRENTLY THERE IS AN UPPER LEVEL SYSTEM TRACKING NORTH NORTHEAST
MISSOURI TOWARD LOWER MICHIGAN JUST AS THE WARM FRONT HAPPENS TO
BE CROSSING THE AREA (MORE DUE TO A NORTHERN STREAM SYSTEM
PASSING TO OUR NORTH). WITHOUT THE SOUTHERN STREAM UPPER WAVE
TRACKING INTO THE AREA WE WOULD NOT GET MUCH RAIN FROM THIS
SYSTEM. THE MODELS DO NOT DO WELL WITH TRACKING THESE TYPES OF
SYSTEMS AND A RESULT OF THAT IS THE FORECAST FOR THE TRACK OF THE
PRECIPITATION IS UNCERTAIN SINCE SOME OF THE MODELS SHEAR IT OUT
TO OUR SOUTH AND EAST. I AM GOING WITH THE IDEA IT WILL NOT SHEAR
OUR AS QUICKLY AS SOME MODELS SHOW... MORE IN LINE WITH THE
CURRENT (21Z) RAP MODEL. SO THAT TRACKS SHOWERS ACROSS THE TAF
SITES IN THE 12Z-15Z TIME FRAME. THUNDERSTORMS ARE QUESTIONABLE
SINCE THERE IS LITTLE IF ANY LOW LEVEL JET TO HELP THE CAUSE.
STILL THERE IS SOME MID LEVEL INSTABILITY SO I PUT VCTS FOR THE
I-94 TAFS.
AS FOR CEILINGS THE LOW 60S DEW POINTS COME BACK IN BY MORNING.
THEY ARE CURRENTLY JUST SOUTH OF INTERSTATE 80... NOT FAR AWAY.
SEEMS TO ME AS THAT MOIST AIR RETURNS WE SHOULD SEE EXTENSIVE IFR
CIGS. ONCE THE WARM FRONT GETS FARTHER NORTH... CIGS SHOULD
IMPROVE SOME (21Z TIME FRAME).
&&
.MARINE...
ISSUED AT 319 PM EDT WED OCT 2 2013
NO CONCERNS IN THE SHORT TERM. WINDS FROM THE SOUTH WILL INCREASE
THURSDAY AND THURSDAY NIGHT. LATEST LOCAL RUN OF THE GLERL FORECASTS
UP TO 4 FOOT WAVES DEVELOPING AS EARLY AS THURSDAY NIGHT...SO WILL
MONITOR THE NEED FOR A SMALL CRAFT ADVISORY.
&&
.HYDROLOGY...
ISSUED AT 319 PM EDT WED OCT 2 2013
FAIRLY PERSISTENT AND WIDESPREAD PRECIPITATION IS EXPECTED THROUGH
THE WEEKEND...BUT AREAL PRECIPITATION TOTALS SHOULD REMAIN WELL
BELOW TWO INCHES...AND QUITE PROBABLY BELOW ONE INCH. MAINSTEM
RIVERS SHOULD RESPOND SOMEWHAT TO THIS PRECIPITATION...BUT THEY ARE
EXPECTED TO REMAIN WITHIN BANKFULL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...JK
AVIATION...WDM
HYDROLOGY...TJT
MARINE...TJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
115 PM CDT THU OCT 3 2013
.UPDATE...
FOR 18Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 306 AM CDT THU OCT 3 2013
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW WEAK
RIDGING OVER THE REGION... WITH THE MAIN SHORTWAVE DRIVING WEATHER
THROUGH THE BALANCE OF THE WEEK OUT OVER THE NORTHWEST CONUS. A
SOUTHERN STREAM WAVE CAN BE SEEN OVER KANSAS/OKLAHOMA... WHICH
WILL MOVE BY TO OUR SOUTH TODAY AND POTENTIALLY HELP KEEP
SHRA/TSRA GOING OVER THE SOUTHERN AND SOUTHEAST PORTION OF THE
AREA FOR A GOOD PART OF THE DAY. RADAR IMAGERY SHOWS MOST OF THE
PCPN FROM LAST EVENING NOW OUT OF THE AREA... BUT SOME ADDITIONAL
DEVELOP IS OCCURRING OVER IOWA NEAR THE STALLED BAROCLINIC ZONE.
AN MCV FROM THE ACTIVITY OVER NEBRASKA WILL LIKELY KICK EAST-
NORTHEAST TODAY AS WELL... FURTHER COMPLICATING THINGS. HIGH
RESOLUTION GUIDANCE... RANGING FROM LOCAL WRF TO HOPWRF TO SPCNMM
TO HRRR TO THE HIGH RES WINDOWS... GENERALLY SUGGEST THE BULK OF
ANY ACTIVITY TODAY AND TONIGHT WILL BE OVER THE SOUTHERN/EASTERN
PORTION OF THE AREA WHERE THERE LOOKS TO BE A BIT MORE FORCING IN
COMBINATION WITH PERSISTENT CONVECTIVE INSTABILITY IN THE
850-500MB LAYER. HOWEVER... CAN/T RULE OUT SOME SHRA AND EVEN TSRA
FARTHER NORTH WITH THE 850MB FRONT REMAINING NEARLY STATIONARY
FROM WEST CENTRAL INTO NORTHEAST MINNESOTA FROM THIS AFTERNOON
THROUGH TONIGHT. FRONTOGENESIS LOOKS TO INCREASE NEAR THAT
BOUNDARY LATER IN THE DAY WITH BOTH CONVERGENCE AND DEFORMATION
STRENGTHENING AS THE UPPER WAVE BEGINS TO MOVE EAST AND THE
925-850 TROUGH SHARPENS. SO... GENERALLY WENT WITH EXITING POPS
EARLY THIS MORNING... THEN A RETURN OF LOWER POPS THROUGH THE DAY
INCREASING TONIGHT... WITH HIGHER POPS OVER THE SOUTHERN PORTION
OF THE AREA. CAN/T DISCOUNT THE POSSIBILITY OF THUNDER ANYWHERE IN
THE CWFA GIVEN CONTINUED 850-500MB DIFFERENTIAL THETA-E VALUES OF
BELOW ZERO OVER ALL BUT THE FAR NORTHWEST PORTION OF THE AREA...
AND SEE NO REASON TO SPLIT HAIRS AND REMOVE THUNDER FOR SUCH A
SMALL AREA. OF COURSE... ANY CONVECTION TODAY AND TONIGHT LOOKS TO
BE ELEVATED AND WORKING WITH MARGINAL MUCAPE... SO DON/T
ANTICIPATE ANY SEVERE STORMS UNLESS SOMETHING NEAR THE BORDER WITH
IOWA WERE TO GET FRISKY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 306 AM CDT THU OCT 3 2013
FRIDAY THROUGH SUNDAY...COMPLICATED EVENT FOR THE END OF THE WEEK
THROUGH THE WEEKEND...PARTICULARLY WITH RESPECT TO THE MESOSCALE
DETAILS...BUT THE SYNOPTIC SCENARIO FOR A POTENT CLASSIC MID-
LATITUDE CYCLONE IS PLAINLY EVIDENT WHETHER USING THE GFS...EC...
GEM OR FIM MODELS. THE DEVELOPING LOW PRES CENTER IN THE LEE OF
THE CENTRAL ROCKIES WILL BE PICKED UP BY A DIGGING LONGWAVE UPR
LVL TROF WHICH WILL DROP AS FAR S AS THE 4-CORNERS REGION. POTENT
PVA AND H7 OMEGA LIFT IN ADVANCE OF THIS SYSTEM...ALONG WITH A
DEEP MOISTURE PLUME MOVING NWD FROM THE GOMEX REGION...WILL MAKE
FOR PLENTY OF RAINFALL DEVELOPMENT...ALONG WITH A FEW EMBEDDED
TSTMS...DURG THE DAY ON FRI. A QUASI-STNRY SFC FNT IN ADVANCE OF
THE SFC LOW...STRETCHING NEWD FROM WRN KS THRU SRN MN...WILL ACT
AS NOT ONLY A LOW LEVEL CONVERGENCE BNDRY FOR LIFT AND THE DEEP
MOISTURE BUT ALSO AS A PATHWAY FOR THE LEE SIDE LOW TO TRAVEL. AS
THE LOW APPROACHES...KEY POINTS TO NOTE WILL BE STRONG DYNAMICS
THAT WILL ALLOW FOR WINDS VEERING WITH HEIGHT...MODEST INSTABILITY
INCREASES...AND SFC HEATING NEAR AND S OF THE LINGERING SFC FRONT.
THESE FACTORS WILL AID IN THE DEVELOPMENT OF SEVERE
WX...PARTICULARLY OVER FAR SRN MN INTO SRN WI. STILL A LITTLE
EARLY TO BETTER PIN DOWN LOCATION BUT SPC HAS CARRIED OVER ITS 30
PERCENT SLGT RISK OF SEVERE WX AREA ALONG WITH THE HATCHED AREA
FOR SIGNIFICANT SEVERE IN THE AFOREMENTIONED REGIONS. HAVE NO
REASON TO DISPUTE THIS AND DO STRONGLY SUPPORT IT. AS FOR
TIMING...SINCE TSTMS WILL LIKELY BE ONGOING FRI MRNG...THERE WILL
BE A BREAK IN THE ACTION SO ALTHOUGH LIKELY POPS ARE ADVERTISED
FOR MUCH OF THE CWFA...THE PRECIP WILL NOT BE CONTINUOUS. THESE
BREAKS WILL ALLOW THE ATMOS TO LOAD ITSELF UP FOR EVENING TO
NIGHTTIME SEVERE WX DEVELOPMENT...WHICH LOOKS TO HAVE THE BEST
TIMING SINCE THE SFC LOW WILL BE MOVING INTO SWRN MN AND THE UPR
TROF WILL PIVOT AND BE DISPLACED TO THE W. BOTH FEATURES... SFC
AND ALOFT...WILL CROSS THE REGION SAT INTO SAT NIGHT...SO THE
HEIGHT FALLS COMBINED WITH THE TILTED ORIENTATION OF THE LOW WILL
MAKE FOR AN EFFICIENT PRECIPITATION MAKING SYSTEM FRI NIGHT INTO
SAT. THIS PERIOD LOOKS TO HAVE THE HIGHEST WIDESPREAD QPF...AS
OPPOSED TO MORE SPOTTY HEAVIER PRECIP FRI INTO FRI EVE. THE SYSTEM
WILL STEADILY PULL AWAY FROM THE REGION SAT NIGHT INTO SUN...
LEAVING MORE LIGHTER SHOWERS IN PLACE AS CONDITIONS SLOWLY
IMPROVE. OVERALL...1-2 INCHES OF QPF IS NOT UNREASONABLE WITH
HIGHER ISOLD AMOUNTS POSSIBLE. OF NOTE IN THE GFS AND GEM
DEPICTIONS IS A DRY SLOW THAT WILL MOVE ACRS THE REGION LATE SAT
AND SAT NIGHT. WITH THE SYSTEM BECOMING SO WOUND UP SO AS TO
ENVELOP DRY AIR...THIS IS ALSO NOT UNREASONABLE AND MAY POKE A
HOLE IN THE HIGH POPS BEING ADVERTISED. SO...THE MESSAGE TO TAKE
AWAY HERE IS THAT DESPITE THE HIGH POPS...THERE WILL BE BREAKS IN
THE PRECIP BUT MODEL UNCERTAINTIES MAKE TIMING SUCH BREAKS
PROBLEMATIC ATTM. AS FOR TEMPS...A COOLING TREND IN CERTAINLY IN
THE OFFING WITH THE CLOUD/PRECIP COMPLICATIONS FOLLOWED BY CAA AS
THE SYSTEM EXITS. A LARGE SPREAD IN HIGHS IS EXPECTED FRI AS THE
LINGERING FRONT MOVES INTO SRN MN. WITH SUCH A SPREAD AND HEATING
NEAR THE FRONT...PLACEMENT OF THE FRONT IS VITAL TO THE MAX TEMP
FCST SO THERE MAY BE SOME VARIATION TO EXACTLY WHERE HIGHS HIT THE
LOW 70S TO WHERE THEY ONLY HIT THE MID 50S TO UPR 60S. MUCH COOLER
TEMPS ARE TO FOLLOW FOR THE WEEKEND WITH HIGHS ONLY IN THE UPR 40S
THRU THE 50S. AS THE SYSTEM EXITS THE AREA OVER THE WEEKEND...
NIGHTTIME LOWS WILL DROP TO THE UPR 30S TO LWR 40S OVER THE
WEEKEND.
MONDAY THROUGH WEDNESDAY...A MORE TRANQUIL AND COOLER PATTERN IS
EXPECTED FOR THE START OF THE WORKWEEK AS COOL/DRY HIGH PRES DROPS
IN FROM WRN CANADA. IT WILL NOT BE A PROLONGED DRY PERIOD...NOR
OVERLY COOL...HOWEVER AS UPPER LEVEL FLOW WILL REMAIN FAIRLY ZONAL
AND VERY PROGRESSIVE. THIS WILL ALLOW THE ARRIVAL OF A CLIPPER-
TYPE SYSTEM TUE NIGHT INTO WED. STILL MUCH MODEL VARIATION...BOTH
IN SINGLE RUN-TO-RUN COMPARISON AND BETWEEN-MODEL COMPARISON...
PREVENTS THE OVERLY HIGH POPS SOME MODELS PRODUCE SO HAVE KEPT
POPS AS SLGT CHC ON WED. TEMPS DO GO ON A WARMING TREND DURG THE
FIRST PART OF NEXT WEEK AS WAA COMMENCES AHEAD OF THE MIDWEEK
SYSTEM. HIGHS CLIMB THRU THE 60S MON-TUE TO REACH THE LOWER 70S
BY WED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 115 PM CDT THU OCT 3 2013
IFR CIGS EXPECTED TO PREVAIL THROUGH THE PERIOD...WITH A REDUCTION
TO LIFR CIGS POSSIBLE OVERNIGHT. AFTER THE BAND OF SHOWERS AFFECTS
NORTHERN/EASTERN TAF SITES EARLY THIS AFTERNOON /ALL BUT
KRWF/...EXPECT A SHORT BREAK DURING THE MID TO LATE AFTERNOON AND
EARLY EVE UNTIL THE NEXT ROUND OF SHOWERS OVER THE DAKOTAS EXPANDS
EASTWARD ACROSS THE SITES. FOG DEVELOPMENT AND DRIZZLE WILL ALSO
BE POSSIBLE OVERNIGHT IN THE VICINITY OF THE WARM FRONT...WITH THE
LOWEST VSBYS /VLIFR/ POSSIBLE AT KRWF/KEAU/KRNH OVERNIGHT AND
FRIDAY MORNING. WINDS WILL BE EAST/NORTHEAST AT 8-13KTS THROUGH
THE PERIOD.
KMSP...
CIGS EXPECTED TO STAY BELOW 1000 FT THROUGH TONIGHT...POSSIBLY
DIPPING BELOW 500 FT PRIMARILY AFTER 06Z FRIDAY. CIGS MAY BECOME
VFR AROUND 18Z FRIDAY...BUT CONFIDENCE IS NOT HIGH. MVFR VSBY
REDUCTIONS WITH SCATTERED RAIN SHOWERS/DRIZZLE AND BR WILL BE
POSSIBLE TONIGHT...PRIMARILY AFTER 06Z FRIDAY.
/OUTLOOK FOR KMSP/
FRI NIGHT...MVFR CIGS/VSBYS EXPECTED...IFR POSSIBLE. SHRA LIKELY
WITH TS POSSIBLE. E WIND 5-15 KT.
SAT...MVFR CIGS/VSBYS EXPECTED...IFR POSSIBLE. SHRA LIKELY WITH TS
POSSIBLE. SE WIND 10-20 KT BECOMING SW.
SUN...MVFR CIGS POSSIBLE EARLY. NW WIND 5-15 KT BECOMING W LESS
THAN 10 KT.
MON...VFR. W WIND 10-20 KT BECOMING NW.
TUE...VFR. LIGHT S WIND INCREASING TO 10-20 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...TRH
SHORT TERM...TRH
LONG TERM...JPC
AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
617 AM CDT THU OCT 3 2013
.UPDATE...
ISSUED AT 606 AM CDT THU OCT 3 2013
UPDATED FOR 12Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 306 AM CDT THU OCT 3 2013
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW WEAK
RIDGING OVER THE REGION... WITH THE MAIN SHORTWAVE DRIVING WEATHER
THROUGH THE BALANCE OF THE WEEK OUT OVER THE NORTHWEST CONUS. A
SOUTHERN STREAM WAVE CAN BE SEEN OVER KANSAS/OKLAHOMA... WHICH
WILL MOVE BY TO OUR SOUTH TODAY AND POTENTIALLY HELP KEEP
SHRA/TSRA GOING OVER THE SOUTHERN AND SOUTHEAST PORTION OF THE
AREA FOR A GOOD PART OF THE DAY. RADAR IMAGERY SHOWS MOST OF THE
PCPN FROM LAST EVENING NOW OUT OF THE AREA... BUT SOME ADDITIONAL
DEVELOP IS OCCURRING OVER IOWA NEAR THE STALLED BAROCLINIC ZONE.
AN MCV FROM THE ACTIVITY OVER NEBRASKA WILL LIKELY KICK EAST-
NORTHEAST TODAY AS WELL... FURTHER COMPLICATING THINGS. HIGH
RESOLUTION GUIDANCE... RANGING FROM LOCAL WRF TO HOPWRF TO SPCNMM
TO HRRR TO THE HIGH RES WINDOWS... GENERALLY SUGGEST THE BULK OF
ANY ACTIVITY TODAY AND TONIGHT WILL BE OVER THE SOUTHERN/EASTERN
PORTION OF THE AREA WHERE THERE LOOKS TO BE A BIT MORE FORCING IN
COMBINATION WITH PERSISTENT CONVECTIVE INSTABILITY IN THE
850-500MB LAYER. HOWEVER... CAN/T RULE OUT SOME SHRA AND EVEN TSRA
FARTHER NORTH WITH THE 850MB FRONT REMAINING NEARLY STATIONARY
FROM WEST CENTRAL INTO NORTHEAST MINNESOTA FROM THIS AFTERNOON
THROUGH TONIGHT. FRONTOGENESIS LOOKS TO INCREASE NEAR THAT
BOUNDARY LATER IN THE DAY WITH BOTH CONVERGENCE AND DEFORMATION
STRENGTHENING AS THE UPPER WAVE BEGINS TO MOVE EAST AND THE
925-850 TROUGH SHARPENS. SO... GENERALLY WENT WITH EXITING POPS
EARLY THIS MORNING... THEN A RETURN OF LOWER POPS THROUGH THE DAY
INCREASING TONIGHT... WITH HIGHER POPS OVER THE SOUTHERN PORTION
OF THE AREA. CAN/T DISCOUNT THE POSSIBILITY OF THUNDER ANYWHERE IN
THE CWFA GIVEN CONTINUED 850-500MB DIFFERENTIAL THETA-E VALUES OF
BELOW ZERO OVER ALL BUT THE FAR NORTHWEST PORTION OF THE AREA...
AND SEE NO REASON TO SPLIT HAIRS AND REMOVE THUNDER FOR SUCH A
SMALL AREA. OF COURSE... ANY CONVECTION TODAY AND TONIGHT LOOKS TO
BE ELEVATED AND WORKING WITH MARGINAL MUCAPE... SO DON/T
ANTICIPATE ANY SEVERE STORMS UNLESS SOMETHING NEAR THE BORDER WITH
IOWA WERE TO GET FRISKY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 306 AM CDT THU OCT 3 2013
FRIDAY THROUGH SUNDAY...COMPLICATED EVENT FOR THE END OF THE WEEK
THROUGH THE WEEKEND...PARTICULARLY WITH RESPECT TO THE MESOSCALE
DETAILS...BUT THE SYNOPTIC SCENARIO FOR A POTENT CLASSIC MID-
LATITUDE CYCLONE IS PLAINLY EVIDENT WHETHER USING THE GFS...EC...
GEM OR FIM MODELS. THE DEVELOPING LOW PRES CENTER IN THE LEE OF
THE CENTRAL ROCKIES WILL BE PICKED UP BY A DIGGING LONGWAVE UPR
LVL TROF WHICH WILL DROP AS FAR S AS THE 4-CORNERS REGION. POTENT
PVA AND H7 OMEGA LIFT IN ADVANCE OF THIS SYSTEM...ALONG WITH A
DEEP MOISTURE PLUME MOVING NWD FROM THE GOMEX REGION...WILL MAKE
FOR PLENTY OF RAINFALL DEVELOPMENT...ALONG WITH A FEW EMBEDDED
TSTMS...DURG THE DAY ON FRI. A QUASI-STNRY SFC FNT IN ADVANCE OF
THE SFC LOW...STRETCHING NEWD FROM WRN KS THRU SRN MN...WILL ACT
AS NOT ONLY A LOW LEVEL CONVERGENCE BNDRY FOR LIFT AND THE DEEP
MOISTURE BUT ALSO AS A PATHWAY FOR THE LEE SIDE LOW TO TRAVEL. AS
THE LOW APPROACHES...KEY POINTS TO NOTE WILL BE STRONG DYNAMICS
THAT WILL ALLOW FOR WINDS VEERING WITH HEIGHT...MODEST INSTABILITY
INCREASES...AND SFC HEATING NEAR AND S OF THE LINGERING SFC FRONT.
THESE FACTORS WILL AID IN THE DEVELOPMENT OF SEVERE
WX...PARTICULARLY OVER FAR SRN MN INTO SRN WI. STILL A LITTLE
EARLY TO BETTER PIN DOWN LOCATION BUT SPC HAS CARRIED OVER ITS 30
PERCENT SLGT RISK OF SEVERE WX AREA ALONG WITH THE HATCHED AREA
FOR SIGNIFICANT SEVERE IN THE AFOREMENTIONED REGIONS. HAVE NO
REASON TO DISPUTE THIS AND DO STRONGLY SUPPORT IT. AS FOR
TIMING...SINCE TSTMS WILL LIKELY BE ONGOING FRI MRNG...THERE WILL
BE A BREAK IN THE ACTION SO ALTHOUGH LIKELY POPS ARE ADVERTISED
FOR MUCH OF THE CWFA...THE PRECIP WILL NOT BE CONTINUOUS. THESE
BREAKS WILL ALLOW THE ATMOS TO LOAD ITSELF UP FOR EVENING TO
NIGHTTIME SEVERE WX DEVELOPMENT...WHICH LOOKS TO HAVE THE BEST
TIMING SINCE THE SFC LOW WILL BE MOVING INTO SWRN MN AND THE UPR
TROF WILL PIVOT AND BE DISPLACED TO THE W. BOTH FEATURES... SFC
AND ALOFT...WILL CROSS THE REGION SAT INTO SAT NIGHT...SO THE
HEIGHT FALLS COMBINED WITH THE TILTED ORIENTATION OF THE LOW WILL
MAKE FOR AN EFFICIENT PRECIPITATION MAKING SYSTEM FRI NIGHT INTO
SAT. THIS PERIOD LOOKS TO HAVE THE HIGHEST WIDESPREAD QPF...AS
OPPOSED TO MORE SPOTTY HEAVIER PRECIP FRI INTO FRI EVE. THE SYSTEM
WILL STEADILY PULL AWAY FROM THE REGION SAT NIGHT INTO SUN...
LEAVING MORE LIGHTER SHOWERS IN PLACE AS CONDITIONS SLOWLY
IMPROVE. OVERALL...1-2 INCHES OF QPF IS NOT UNREASONABLE WITH
HIGHER ISOLD AMOUNTS POSSIBLE. OF NOTE IN THE GFS AND GEM
DEPICTIONS IS A DRY SLOW THAT WILL MOVE ACRS THE REGION LATE SAT
AND SAT NIGHT. WITH THE SYSTEM BECOMING SO WOUND UP SO AS TO
ENVELOP DRY AIR...THIS IS ALSO NOT UNREASONABLE AND MAY POKE A
HOLE IN THE HIGH POPS BEING ADVERTISED. SO...THE MESSAGE TO TAKE
AWAY HERE IS THAT DESPITE THE HIGH POPS...THERE WILL BE BREAKS IN
THE PRECIP BUT MODEL UNCERTAINTIES MAKE TIMING SUCH BREAKS
PROBLEMATIC ATTM. AS FOR TEMPS...A COOLING TREND IN CERTAINLY IN
THE OFFING WITH THE CLOUD/PRECIP COMPLICATIONS FOLLOWED BY CAA AS
THE SYSTEM EXITS. A LARGE SPREAD IN HIGHS IS EXPECTED FRI AS THE
LINGERING FRONT MOVES INTO SRN MN. WITH SUCH A SPREAD AND HEATING
NEAR THE FRONT...PLACEMENT OF THE FRONT IS VITAL TO THE MAX TEMP
FCST SO THERE MAY BE SOME VARIATION TO EXACTLY WHERE HIGHS HIT THE
LOW 70S TO WHERE THEY ONLY HIT THE MID 50S TO UPR 60S. MUCH COOLER
TEMPS ARE TO FOLLOW FOR THE WEEKEND WITH HIGHS ONLY IN THE UPR 40S
THRU THE 50S. AS THE SYSTEM EXITS THE AREA OVER THE WEEKEND...
NIGHTTIME LOWS WILL DROP TO THE UPR 30S TO LWR 40S OVER THE
WEEKEND.
MONDAY THROUGH WEDNESDAY...A MORE TRANQUIL AND COOLER PATTERN IS
EXPECTED FOR THE START OF THE WORKWEEK AS COOL/DRY HIGH PRES DROPS
IN FROM WRN CANADA. IT WILL NOT BE A PROLONGED DRY PERIOD...NOR
OVERLY COOL...HOWEVER AS UPPER LEVEL FLOW WILL REMAIN FAIRLY ZONAL
AND VERY PROGRESSIVE. THIS WILL ALLOW THE ARRIVAL OF A CLIPPER-
TYPE SYSTEM TUE NIGHT INTO WED. STILL MUCH MODEL VARIATION...BOTH
IN SINGLE RUN-TO-RUN COMPARISON AND BETWEEN-MODEL COMPARISON...
PREVENTS THE OVERLY HIGH POPS SOME MODELS PRODUCE SO HAVE KEPT
POPS AS SLGT CHC ON WED. TEMPS DO GO ON A WARMING TREND DURG THE
FIRST PART OF NEXT WEEK AS WAA COMMENCES AHEAD OF THE MIDWEEK
SYSTEM. HIGHS CLIMB THRU THE 60S MON-TUE TO REACH THE LOWER 70S
BY WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 606 AM CDT THU OCT 3 2013
THINGS CONTINUE TO LOOK UNFAVORABLE FOR AVIATION CONCERNS THROUGH
THE FORECAST PERIOD... WITH THE WORST CONDITIONS LIKELY OVER THE
SOUTHEAST TWO-THIRDS OR SO OF THE AREA. MVFR CEILINGS AND
VISIBILITIES WILL BE THE RULE WITH FREQUENT IFR CONDITIONS AND
SOME LIFR LIKELY AS WELL. MUCH WILL DEPEND ON TIMING OF PCPN...
WHICH MAY HELP BREAK LOWER CEILINGS UP AT TIMES... BUT THINGS WILL
GENERALLY WORSEN IN THEIR WAKE. THERE WILL UNDOUBTEDLY BE SOME
CONVECTIVE ELEMENTS WITH THUNDERSTORMS AROUND... MAINLY FROM KMSP
SOUTH/EAST... BUT CONFIDENCE IN THE TIMING FOR THUNDERSTORMS IS
VERY LOW... SO DID NOT MENTION MUCH SPECIFICALLY AT THIS POINT AND
INSTEAD STRESSED THE OVERALL POOR FLIGHT CONDITIONS THAT ARE
EXPECTED TO PREDOMINATE AS NORTHEAST AND EASTERLY LOW LEVEL FLOW
WORK TO KEEP PLENTY OF LOW LEVEL MOISTURE IN THE AREA.
KMSP...CONFIDENCE IN FORECAST SPECIFICS IS LOW WITH POTENTIAL
TIMING ISSUES OF SEVERAL HOURS ALONG WITH WITH VARIATIONS OF AT
LEAST A FLIGHT CATEGORY POSSIBLE FOR CEILINGS AND VISIBILITIES. IN
GENERAL... EXPECT AND INCREASE IN PCPN COVERAGE AGAIN LATER TODAY
INTO TONIGHT... BUT CAN/T RULE OUT SOMETHING AT ALMOST ANY TIME
GIVEN PERSISTENT WARM ADVECTION ALOFT ALONG WITH LINGERING INSTABILITY.
/OUTLOOK FOR KMSP/
FRIDAY AFTERNOON...MVFR CEILINGS AND VISIBILITIES EXPECTED... IFR
POSSIBLE. RAIN WITH A CHANCE OF THUNDER. NORTHEAST WIND 5 TO 15 KT
BECOMING EAST.
SATURDAY...MVFR CEILINGS AND VISIBILITIES EXPECTED... IFR
POSSIBLE. RAIN WITH A CHANCE OF THUNDER. SOUTHEAST WIND 10 TO 20
KT BECOMING SOUTHWEST.
SATURDAY NIGHT...MVFR CEILINGS POSSIBLE. CHANCE OF SHOWERS.
SOUTHWEST WIND LESS THAN 10 KT.
SUNDAY...MVFR CEILINGS EXPECTED. MVFR VISIBILITIES POSSIBLE.
CHANCE OF SHOWERS. NORTHWEST WIND 10 TO 20 KT.
SUNDAY NIGHT...MVFR CEILINGS POSSIBLE EARLY. NORTHWEST WIND 5 TO
15 KT BECOMING WEST LESS THAN 10 KT.
MONDAY...VFR. WEST WIND 10 TO 20 KT BECOMING NORTHWEST.
MONDAY NIGHT...VFR. NORTHWEST WIND LESS THEN 10 KT BECOMING LIGHT
AND VARIABLE.
TUESDAY...VFR. SOUTH WIND INCREASING TO 10 TO 20 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...
SHORT TERM...
LONG TERM...JPC
AVIATION...
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
431 AM CDT THU OCT 3 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 306 AM CDT THU OCT 3 2013
LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW WEAK
RIDGING OVER THE REGION... WITH THE MAIN SHORTWAVE DRIVING WEATHER
THROUGH THE BALANCE OF THE WEEK OUT OVER THE NORTHWEST CONUS. A
SOUTHERN STREAM WAVE CAN BE SEEN OVER KANSAS/OKLAHOMA... WHICH
WILL MOVE BY TO OUR SOUTH TODAY AND POTENTIALLY HELP KEEP
SHRA/TSRA GOING OVER THE SOUTHERN AND SOUTHEAST PORTION OF THE
AREA FOR A GOOD PART OF THE DAY. RADAR IMAGERY SHOWS MOST OF THE
PCPN FROM LAST EVENING NOW OUT OF THE AREA... BUT SOME ADDITIONAL
DEVELOP IS OCCURRING OVER IOWA NEAR THE STALLED BAROCLINIC ZONE.
AN MCV FROM THE ACTIVITY OVER NEBRASKA WILL LIKELY KICK EAST-
NORTHEAST TODAY AS WELL... FURTHER COMPLICATING THINGS. HIGH
RESOLUTION GUIDANCE... RANGING FROM LOCAL WRF TO HOPWRF TO SPCNMM
TO HRRR TO THE HIGH RES WINDOWS... GENERALLY SUGGEST THE BULK OF
ANY ACTIVITY TODAY AND TONIGHT WILL BE OVER THE SOUTHERN/EASTERN
PORTION OF THE AREA WHERE THERE LOOKS TO BE A BIT MORE FORCING IN
COMBINATION WITH PERSISTENT CONVECTIVE INSTABILITY IN THE
850-500MB LAYER. HOWEVER... CAN/T RULE OUT SOME SHRA AND EVEN TSRA
FARTHER NORTH WITH THE 850MB FRONT REMAINING NEARLY STATIONARY
FROM WEST CENTRAL INTO NORTHEAST MINNESOTA FROM THIS AFTERNOON
THROUGH TONIGHT. FRONTOGENESIS LOOKS TO INCREASE NEAR THAT
BOUNDARY LATER IN THE DAY WITH BOTH CONVERGENCE AND DEFORMATION
STRENGTHENING AS THE UPPER WAVE BEGINS TO MOVE EAST AND THE
925-850 TROUGH SHARPENS. SO... GENERALLY WENT WITH EXITING POPS
EARLY THIS MORNING... THEN A RETURN OF LOWER POPS THROUGH THE DAY
INCREASING TONIGHT... WITH HIGHER POPS OVER THE SOUTHERN PORTION
OF THE AREA. CAN/T DISCOUNT THE POSSIBILITY OF THUNDER ANYWHERE IN
THE CWFA GIVEN CONTINUED 850-500MB DIFFERENTIAL THETA-E VALUES OF
BELOW ZERO OVER ALL BUT THE FAR NORTHWEST PORTION OF THE AREA...
AND SEE NO REASON TO SPLIT HAIRS AND REMOVE THUNDER FOR SUCH A
SMALL AREA. OF COURSE... ANY CONVECTION TODAY AND TONIGHT LOOKS TO
BE ELEVATED AND WORKING WITH MARGINAL MUCAPE... SO DON/T
ANTICIPATE ANY SEVERE STORMS UNLESS SOMETHING NEAR THE BORDER WITH
IOWA WERE TO GET FRISKY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 306 AM CDT THU OCT 3 2013
FRIDAY THROUGH SUNDAY...COMPLICATED EVENT FOR THE END OF THE WEEK
THROUGH THE WEEKEND...PARTICULARLY WITH RESPECT TO THE MESOSCALE
DETAILS...BUT THE SYNOPTIC SCENARIO FOR A POTENT CLASSIC MID-
LATITUDE CYCLONE IS PLAINLY EVIDENT WHETHER USING THE GFS...EC...
GEM OR FIM MODELS. THE DEVELOPING LOW PRES CENTER IN THE LEE OF
THE CENTRAL ROCKIES WILL BE PICKED UP BY A DIGGING LONGWAVE UPR
LVL TROF WHICH WILL DROP AS FAR S AS THE 4-CORNERS REGION. POTENT
PVA AND H7 OMEGA LIFT IN ADVANCE OF THIS SYSTEM...ALONG WITH A
DEEP MOISTURE PLUME MOVING NWD FROM THE GOMEX REGION...WILL MAKE
FOR PLENTY OF RAINFALL DEVELOPMENT...ALONG WITH A FEW EMBEDDED
TSTMS...DURG THE DAY ON FRI. A QUASI-STNRY SFC FNT IN ADVANCE OF
THE SFC LOW...STRETCHING NEWD FROM WRN KS THRU SRN MN...WILL ACT
AS NOT ONLY A LOW LEVEL CONVERGENCE BNDRY FOR LIFT AND THE DEEP
MOISTURE BUT ALSO AS A PATHWAY FOR THE LEE SIDE LOW TO TRAVEL. AS
THE LOW APPROACHES...KEY POINTS TO NOTE WILL BE STRONG DYNAMICS
THAT WILL ALLOW FOR WINDS VEERING WITH HEIGHT...MODEST INSTABILITY
INCREASES...AND SFC HEATING NEAR AND S OF THE LINGERING SFC FRONT.
THESE FACTORS WILL AID IN THE DEVELOPMENT OF SEVERE
WX...PARTICULARLY OVER FAR SRN MN INTO SRN WI. STILL A LITTLE
EARLY TO BETTER PIN DOWN LOCATION BUT SPC HAS CARRIED OVER ITS 30
PERCENT SLGT RISK OF SEVERE WX AREA ALONG WITH THE HATCHED AREA
FOR SIGNIFICANT SEVERE IN THE AFOREMENTIONED REGIONS. HAVE NO
REASON TO DISPUTE THIS AND DO STRONGLY SUPPORT IT. AS FOR
TIMING...SINCE TSTMS WILL LIKELY BE ONGOING FRI MRNG...THERE WILL
BE A BREAK IN THE ACTION SO ALTHOUGH LIKELY POPS ARE ADVERTISED
FOR MUCH OF THE CWFA...THE PRECIP WILL NOT BE CONTINUOUS. THESE
BREAKS WILL ALLOW THE ATMOS TO LOAD ITSELF UP FOR EVENING TO
NIGHTTIME SEVERE WX DEVELOPMENT...WHICH LOOKS TO HAVE THE BEST
TIMING SINCE THE SFC LOW WILL BE MOVING INTO SWRN MN AND THE UPR
TROF WILL PIVOT AND BE DISPLACED TO THE W. BOTH FEATURES... SFC
AND ALOFT...WILL CROSS THE REGION SAT INTO SAT NIGHT...SO THE
HEIGHT FALLS COMBINED WITH THE TILTED ORIENTATION OF THE LOW WILL
MAKE FOR AN EFFICIENT PRECIPITATION MAKING SYSTEM FRI NIGHT INTO
SAT. THIS PERIOD LOOKS TO HAVE THE HIGHEST WIDESPREAD QPF...AS
OPPOSED TO MORE SPOTTY HEAVIER PRECIP FRI INTO FRI EVE. THE SYSTEM
WILL STEADILY PULL AWAY FROM THE REGION SAT NIGHT INTO SUN...
LEAVING MORE LIGHTER SHOWERS IN PLACE AS CONDITIONS SLOWLY
IMPROVE. OVERALL...1-2 INCHES OF QPF IS NOT UNREASONABLE WITH
HIGHER ISOLD AMOUNTS POSSIBLE. OF NOTE IN THE GFS AND GEM
DEPICTIONS IS A DRY SLOW THAT WILL MOVE ACRS THE REGION LATE SAT
AND SAT NIGHT. WITH THE SYSTEM BECOMING SO WOUND UP SO AS TO
ENVELOP DRY AIR...THIS IS ALSO NOT UNREASONABLE AND MAY POKE A
HOLE IN THE HIGH POPS BEING ADVERTISED. SO...THE MESSAGE TO TAKE
AWAY HERE IS THAT DESPITE THE HIGH POPS...THERE WILL BE BREAKS IN
THE PRECIP BUT MODEL UNCERTAINTIES MAKE TIMING SUCH BREAKS
PROBLEMATIC ATTM. AS FOR TEMPS...A COOLING TREND IN CERTAINLY IN
THE OFFING WITH THE CLOUD/PRECIP COMPLICATIONS FOLLOWED BY CAA AS
THE SYSTEM EXITS. A LARGE SPREAD IN HIGHS IS EXPECTED FRI AS THE
LINGERING FRONT MOVES INTO SRN MN. WITH SUCH A SPREAD AND HEATING
NEAR THE FRONT...PLACEMENT OF THE FRONT IS VITAL TO THE MAX TEMP
FCST SO THERE MAY BE SOME VARIATION TO EXACTLY WHERE HIGHS HIT THE
LOW 70S TO WHERE THEY ONLY HIT THE MID 50S TO UPR 60S. MUCH COOLER
TEMPS ARE TO FOLLOW FOR THE WEEKEND WITH HIGHS ONLY IN THE UPR 40S
THRU THE 50S. AS THE SYSTEM EXITS THE AREA OVER THE WEEKEND...
NIGHTTIME LOWS WILL DROP TO THE UPR 30S TO LWR 40S OVER THE
WEEKEND.
MONDAY THROUGH WEDNESDAY...A MORE TRANQUIL AND COOLER PATTERN IS
EXPECTED FOR THE START OF THE WORKWEEK AS COOL/DRY HIGH PRES DROPS
IN FROM WRN CANADA. IT WILL NOT BE A PROLONGED DRY PERIOD...NOR
OVERLY COOL...HOWEVER AS UPPER LEVEL FLOW WILL REMAIN FAIRLY ZONAL
AND VERY PROGRESSIVE. THIS WILL ALLOW THE ARRIVAL OF A CLIPPER-
TYPE SYSTEM TUE NIGHT INTO WED. STILL MUCH MODEL VARIATION...BOTH
IN SINGLE RUN-TO-RUN COMPARISON AND BETWEEN-MODEL COMPARISON...
PREVENTS THE OVERLY HIGH POPS SOME MODELS PRODUCE SO HAVE KEPT
POPS AS SLGT CHC ON WED. TEMPS DO GO ON A WARMING TREND DURG THE
FIRST PART OF NEXT WEEK AS WAA COMMENCES AHEAD OF THE MIDWEEK
SYSTEM. HIGHS CLIMB THRU THE 60S MON-TUE TO REACH THE LOWER 70S
BY WED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM CDT WED OCT 2 2013
SHOWERS AND THUNDERSTORMS WILL BEGIN THE TAF PERIOD FOR KRNH AND
KEAU WITH THE BACK EDGE OF THE ACTIVITY JUST EAST OF KMSP. THE
ACTIVITY IS MOVING EAST AT 30 TO 35 KNOTS AND WILL CLEAR THE WI
TAF SITES BY 08Z. ALTHOUGH CEILINGS REMAIN VFR OUTSIDE OF THE
THUNDERSTORMS LATE THIS EVENING... THE MAIN CONCERN OVERNIGHT IS
THE DEVELOPMENT OF MVFR CEILINGS AS LOW LEVEL SATURATION
INCREASES. CONTINUED THE TREND OF BKN-OVC010-020 AROUND DAYBREAK
WITH FURTHER LOWERING BELOW 010 DURING THE LATE AFTERNOON AND
EVENING. LITTLE RAIN MAY BE ONGOING ANYWHERE TOWARDS DAYBREAK WITH
A SLOW INCREASE IN THE RAIN FROM SOUTH TO NORTH DURING THE DAY.
THEREFORE RE-TIMED THE RAIN IN THE TAFS. MAINLY NE WINDS 6-12
KNOTS.
KMSP...THE MAIN THUNDERSTORM ACTIVITY WILL BE EAST OF THE
AIRFIELD BY 06Z WITH JUST A FEW LINGERING SHOWERS. VFR CONDITIONS
THROUGH MUCH OF THE NIGHT WITH MVFR CEILINGS DEVELOPING IN THE
MORNING. DELAYED THE ONSET OF RAIN UNTIL AROUND MIDDAY WITH
CEILINGS/VSBYS LOWERING TO IFR/MVFR RESPECTIVELY BY EVENING.
MAINLY NE WINDS NEAR 10 KNOTS.
/OUTLOOK FOR KMSP/
FRI...MVFR/IFR LIKELY. SHRA/TSRA LIKELY. WINDS NE 10-15 KTS.
SAT...MVFR/IFR LIKELY. CHC -RA. WINDS SE 10 KTS BECOMING W 10-15
KTS LATE.
SUN...MVFR LIKELY. CHC -RA. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...TRH
LONG TERM...JPC
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1223 PM CDT WED OCT 2 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM CDT WED OCT 2 2013
IT IS A FAIRLY INNOCUOUS LOOKING WEATHER PATTERN ACROSS THE CONUS
THIS MORNING...BUT OF COURSE WE ARE STILL EXPECTING BIG CHANGES
OVER THE NEXT 96 HOURS. THIS WILL BE ADDRESSED IN THE LONG TERM
SECTION OF THIS DISCUSSION BELOW. THE RADAR MOSAIC THIS MORNING
SIMPLY SHOWS A BUNCH OF GROUND CLUTTER ACROSS MN/WI WITH CLOUD
FREE SKIES. HOWEVER...IN THE DAKOTAS MID LEVEL CLOUDS ARE STEADILY
INCREASING IN COVERAGE AND LIGHT ECHOES ARE SHOWING UP ON RADAR.
THESE RETURNS ARE IN AN AREA OF 850 MB WARM ADVECTION AND
UNDERNEATH A 1000-500 MB THICKNESS RIDGE. THE SURFACE FRONT IS A
STATE AWAY AND STRETCHES FROM CO/WY TO SOUTHERN NE/IA AND OVER
TOWARD SOUTHERN LAKE MICHIGAN. THIS PRECIP THAT IS CURRENTLY
DEVELOPING WILL BE VERY LIGHT AND MAY SIMPLY END UP AS VIRGA
SHOWERS THAT MOVE TOWARD NORTHWEST MN. AROUND 20-21Z...MOISTURE
TRANSPORT AND WARM ADVECTION WILL SLIDE EAST AND WE SHOULD GET
NUMEROUS SHOWERS AND WEAK THUNDERSTORMS TO DEVELOP SOUTHWARD WITH
TIME - TOWARD THE MOISTURE ADVECTION. IT WILL TAKE SOME TIME...BUT
EVENTUALLY MOST OF SOUTHERN AND CENTRAL MN WILL GET LIGHT RAIN
BETWEEN 00-06Z...BEFORE MOVING INTO WESTERN WI LATE TONIGHT. WE
PUSHED BACK THE TIMING OF THE ONSET OF RAIN THIS AFTERNOON/EVENING
BACK A COUPLE HOURS TO REFLECT THE LATEST TRENDS...WHICH CAN
PARTLY BE ATTRIBUTED TO THE AMOUNT OF DRY AIR IN PLACE OVER THE
UPPER MISSISSIPPI RIVER VALLEY. THE KABR SOUNDING HAD 0.38" FOR A
PWAT AND WE HAD 0.28" HERE IN CHANHASSEN OFF LAST EVENINGS BALLOON
LAUNCH. THE COMBINATION OF GEM/ECMWF/GFS/NAM AND AVAILABLE HI-RES
MESO MODELS /WRF HRRR RAP/ GUIDANCE SUGGEST A LOT OF LOCATIONS
ACROSS THE FORECAST AREA. WILL END UP WITH 0.20-0.50" OVER THE
NEXT 24 HOURS ON THE HIGH...A COUPLE SOLUTION SUGGEST THE
POTENTIAL FOR 0.75" BY 12Z THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 310 AM CDT WED OCT 2 2013
THURSDAY THROUGH SATURDAY...VERY ACTIVE PATTERN IN THE FIRST HALF
OF THE EXTENDED PORTION OF THE FORECAST. AT THE SFC...A WMFNT
EXTENDING NEWD FROM A PRIMARY LOW PRES CENTER OVER ERN KS WILL BE
THE FOCAL POINT FOR LOW LEVEL CONVERGENCE. DEEP PROLONGED MOISTURE
FETCH FROM THE GOMEX WILL ALLOW FAIRLY WIDESPREAD RAINFALL TO
DEVELOP OVER THE WFO MPX BY THU MRNG. ENHANCING THE PRECIP WILL BE
A DIGGING LONGWAVE TROUGH OVER THE ROCKIES...WHICH WILL DROP INTO
THE FOUR CORNERS REGION BY FRI MRNG. PERIODS OF RAIN WILL CONTINUE
THU...THU NIGHT...FRI...AND FRI NIGHT AS SEVERAL LOW PRES WAVES
TRAVERSE THE LINGERING QUASI-STNRY FRONT OVER THE REGION WHILE ITS
PARENT LOW PRES CENTER SIGNIFICANTLY STRENGTHENS IN ADVANCE OF THE
PIVOTING UPR LEVEL TROF OVER THE CENTRAL PLAINS. VERY STRONG
DYNAMICS WILL BE PRESENT DUE TO THE TILTING-WITH-HEIGHT
DEVELOPMENT OF THIS POTENT LOW PRES SYSTEM...PRODUCING STRONG
JETTING AT MULTIPLE LEVELS WITH VEERING DIRECTIONS GOING UPWARDS
ALONG WITH HEIGHTENED INSTABILITY DUE TO THE MOISTURE SURGE. THIS
ADDS UP TO THE GROWING SEVERE WX THREAT FOR FRIDAY AFTERNOON AND
FRIDAY NIGHT. TIMING IS STILL RATHER QUESTIONABLE DUE TO THE
VARYING TIMING OF BRINGING THE WELL-DEVELOPED LOW PRES CENTER THRU
THE UPR MISS RIVER VALLEY FRI-SAT. NEVERTHELESS...SPC IN ITS DAY 3
OUTLOOK HIGHLIGHTS MUCH OF THE WFO MPX CWFA IN A SLGT RISK...
INCLUDING A 30 PERCENT HATCHED AREA /MEANING SIGNIFICANT SEVERE WX
POSSIBLE/ IN SRN PORTIONS. THE LOW PRES CENTER WILL THEN ROTATE
THRU SRN MN INTO CENTRAL WI FRI NIGHT THRU SAT MRNG...AND THERE
APPEARS TO BE SOME DRY SLOTTING WHICH MAY OCCUR..BUT AGAIN
WHEN/WHERE ARE DIFFICULT QUESTIONS TO ANSWER ATTM. WITH THE SYSTEM
LIFTING AWAY DURG THE DAY ON SAT...THE SEVERE WX THREAT WILL
DIMINISH AND THE PRECIP WILL GRADUALLY TAPER OFF DURG THE DAY. AS
FOR TEMPS DURG THIS PERIOD...THERE WILL BE A VERY NOTICEABLE
COOLING TREND AS DEVELOPING N TO NE LOW LEVEL FLOW N OF THE STNRY
FNT WILL DROP HIGHS FROM THE 60S/70S ON THU TO THE 40S/50S BY SAT
AS THE LOW PRES CENTER ITSELF MOVES ON THRU. SHOULD THE LOW PRES
CENTER TAKE A MORE SLY TRACK...EVEN 50S MAY NOT BE POSSIBLE ON
SAT.
SUNDAY THROUGH TUESDAY...MUCH MORE TRANQUIL PATTERN WILL EMERGE
BUT THE COST WILL BE MUCH COOLER TEMPERATURES FOR THE START OF
NEXT WEEK. STRONG CAA ON THE BACKSIDE OF THE DEPARTING LOW PRES
SYSTEM WILL PRODUCE LOWS IN THE 30S/40S FOR MUCH OF THE CWFA SUN
AND MON MORNINGS. DESPITE PLENTY OF SUN FOR SUNDAY AND MONDAY...
HIGHS WILL ONLY REACH THE LOW 50S ON SUN FOLLOWED BY LOW 60S ON
MON. HIGH PRES WILL BRIEFLY MOVE THRU THE AREA...BEING USHERED
ALONG BY FAIRLY PROGRESSIVE UPPER LEVEL FLOW. ANOTHER LONGWAVE
TROUGH MOVING ONSHORE THE PAC NW SUN NIGHT INTO MON WILL SPAWN
CYCLOGENESIS OFF THE CANADIAN ROCKIES MON AND THIS SYSTEM LOOKS TO
DRAG A CDFNT ACRS THE REGION TUESDAY. DESPITE FAIRLY STRONG
DYNAMICS BOTH AT THE SFC AND ALOFT AS THE TROF AGAIN PIVOTS
SLIGHTLY NEGATIVE AS IT MOVES THRU...THE CDFNT OF THIS SYSTEM WILL
BE HIGHLY DEVOID OF MOISTURE SO HAVE MAINTAINED A DRY FCST ATTM.
HIGHS ONLY IN THE MID 50S TO NEAR 60 ARE EXPECTED WHILE LOWS HOLD
IN THE 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1208 PM CDT WED OCT 2 2013
CONDS WILL BEGIN TO DETERIORATE OVER THE NEXT 6 TO 12 HRS AS
MOISTURE BEGINS TO SURGE NORTHWARD ACROSS THE PLAINS...AND
INTERACTS WITH A FRONTAL BOUNDARY DEVELOPING ACROSS SOUTHERN MN.
TSRA HAVE ALREADY DEVELOPED ALONG THE LEADING EDGE OF A
DISTURBANCE MOVING NE ACROSS NEBRASKA...AND ALONG THE AXIS OF
STRONGER INSTABILITY ABV 5K IN SE SD. ANOTHER AREA OF SHRA/TSRA
CONTINUES TO DEVELOP ACROSS ND/NE SD WHICH WILL MOVE INTO WC/SW MN
THIS AFTN. HOW WIDESPREAD THIS ACTIVITY BECOMES IS THE MAIN
QUESTION AS SHORT TERM MODELS HAVE BEEN FAIRLY CONSISTENT WITH THE
DEVELOPMENT OF THESE SHRA/TSRA...BUT IN A NARROW BAND FROM SW MN
TO WC WI LATE THIS AFTN/EVENING. WILL CONTINUE WITH VFR CIGS THRU
00Z...WITH SOME VSBYS DROPPING TO MVFR OR IFR IN A BRIEF PERIOD IN
HEAVIER SHRA/TSRA. LATER THIS EVENING/OVERNIGHT...CIGS WILL
DECREASE WITH IFR CIGS POSSIBLE AFT 6Z ONCE WINDS BECOME MORE E/NE
ACROSS CENTRAL/WC MN. EVENTUALLY THESE CIGS WILL SPREAD S/SW
ACROSS THE CWA BY THE END OF THE TAF FORECAST PERIOD.
KMSP...
THE MAIN UPDATE TO THIS TAF PERIOD IS TO MOVE THE SHRA IN FASTER
THIS AFTN...AND ADD VCTS BY 00Z AS SHRA/TSRA WILL LIKELY SPREAD NE
ACROSS SW MN DURING THE AFTN...AND EXPAND IN COVERAGE AND
INTENSITY. UPDATES WILL LIKELY OCCUR THIS AFTN ONCE THE COVERAGE
BECOMES MORE WIDESPREAD AND A GENERATE TREND OF THE ACTIVITY IS
NOTED. VSBYS WILL LIKELY DROP TO MVFR OR POSSIBLY IFR IN HEAVIER
SHRA/TSRA. CONDS WILL ALSO DETERIORATE OVERNIGHT/THU AS THE SYSTEM
BEGINS TO WRAP UP ACROSS THE PLAINS. WINDS WILL BE GENERALLY
SE/ESE TODAY...MORE E/ESE TONIGHT...SHIFTING TO THE E/ENE BY
MORNING AND INCREASING.
/OUTLOOK FOR KMSP/
THU NGT...MVFR/IFR LIKELY. PERIODS OF RA. WINDS NE 5-10 KTS.
FRI...MVFR/IFR LIKELY. SHRA/TSRA LIKELY. WINDS NE 10 KTS.
SAT...MVFR/IFR POSSIBLE. CHC -RA. WINDS S 10 KTS BECOMING W
10-15KTS LATE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...JPC
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
700 AM CDT Fri Oct 4 2013
.SHORT TERM...(Today through Saturday)
Issued at 414 AM CDT FRI OCT 4 2013
The next 48 hours will be a tale of two air masses, one more common
during mid-summer and the other more like late Fall. Much better
agreement between the models on timing of the cold front as well as
the placement of the upper level trough lends to a more confident
forecast and increase in PoPs with the frontal boundary.
For today a strong upper trough over the Great Basin centered just
east of SLC will lift northeast and into the Northern and Central
Plains by Saturday. Increasing downstream pressure falls have
already induced a surface low over northwest KS which will deepen
and likewise track northeast as the increasing dynamics aloft
overspread the Plains. A large warm sector exists east of the
Central Rockies with an impressive southwesterly low level jet in
excess of 50kts extending through OK, KS and western MO. A narrow
band of scattered elevated convection has formed as the right rear
quad of a 70kt wind max at 200mb encounters an axis of MLCAPES
around 1000 J/kg aligned near the low level jet axis. Earlier
versions of the HRRR and the 00Z NAM did a good job of forecasting
this activity. Expect this convection to spread across northwest MO
and northeast KS this morning before weakening towards the noon
hour. The afternoon hours should be mainly dry except for late in
the day over northwest MO. Temperatures will be impacted by the
increasing mid level cloud cover this morning and the convection
over northwest MO. However, should see clouds scatter out this
afternoon and allow good mixing to reach highs well into the 80s.
The weather will become quite active this evening as a convection
rapidly forms along a cold front over KS and southeast NE. This
boundary is attached to the low pressure center and will swing
eastward through the CWA. Given a moderate to highly unstable
airmass with over 2000 J/kg of MLCAPE plus the above noted h8 jet
and steepening mid level lapse rates due to cold air aloft
overspreading the region, the cap now in place will be lifted
allowing for rapid development of convection along the frontal
boundary. Expect this activity to form over eastern KS and southeast
NE by late afternoon and enter the far northwest CWA around 00Z.
Severe storms will be possible this evening mainly west of the I-35
corridor with large hail and damaging winds initially and as the
squall line matures evolving into a high wind threat. With
precipitable water values progged close to two standard deviations
above normal any training cells will produce very heavy rainfall.
This may be especially true after midnight as the NAM hints at post
frontal elevated convection forming due to increasing frontogenesis
within the 850-750mb layer.
While the cold front is expected to clear the CWA by Saturday
morning the post frontal stratiform rain with embedded thunder will
likely linger through Saturday morning over the eastern half of the
CWA. A major influx of cold air will be ushered into the CWA on
gusty westerly winds. Even with clearing skies the cold air
advection will overwhelm what little warming the sun will provide.
As such temperatures will struggle to warm much past 60 over the
western half of the CWA. Saturday night promises a need to turn on
your furnace as deep cold air advection continues with h8 temperatures
around 0C possible. Should see some lows fall into the upper 30s
across northern MO.
.LONG TERM...(Sunday through Thursday)
Issued at 414 AM CDT FRI OCT 4 2013
Model differences in the beginning of the extended period will make
for a tricky forecast on Sunday. The associated upper level trough,
that will be responsible for driving a cold front through the area
Friday night into Saturday morning, will develop a cut off low in
the base of the trough. This upper low will be a slow mover and by
Sunday is expected to be moving north of the CWA. However, models
are different as to the placement of the low. The EC and GFS
ensemble mean are the slowest and furthest south taking the upper
low across Iowa on the day Sunday. The operational GFS and GEM are
further north and more progressive with the upper low. The GEM and
operational GFS would lead to a dry and slightly warmer solution
whereas, the GFS ensemble and EC solution would be cooler with even
a chance for some light precipitation across northern Missouri. for
now, sided with the ALLBlend which is a compromise solution in
keeping conditions dry with highs in the upper 50 and lower 60s. As
surface high pressure builds in Sunday night temperatures will
bottom out in the lower 40s.
Beyond Sunday, the general trend amongst models is similar in
keeping conditions dry with a warming trend. Monday will be a
transitional day with northwest flow aloft behind the departing
upper level system. A return to southwesterly flow and plentiful
sunshine should allow highs to warm into the mid 60s to near 70.
Tuesday, an upper level ridge will begin to build into the area in
response to an upper level trough digging southward down the western
CONUS. This upper level ridge is expected to dominate the area as
well as much of the eastern half of the CONUS through Thursday.
Highs will warm through the middle part of the week with highs in
the mid to upper 70s by Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 651 AM CDT FRI OCT 4 2013
Band of scattered showers and storms will affect far northwest MO
and northeast KS this morning, missing the Kansas City terminals and
may pass just to the west of KSTJ. MVFR stratus has formed in the
very humid airmass and latest BUFR soundings indicate these ceilings
will linger into the late morning before lifting.
Attention then turns to this evening when a band of strong/possibly
severe storms forms along a cold front. Models are in good agreement
with timing giving a boost to confidence. Expect showers and storms
to pass through the terminals during the evening hours. VFR ceilings
most likely except with the heavy showers which could lower ceilings
to MVFR with IFR visibilities. Frontal passage likely with initial
line of storms but convection will linger well past the passage of
the front.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...73
AVIATION...MJ
AREA FORECAST DISCUSSION...CORRECTED
NWS KANSAS CITY/PLEASANT HILL MO
435 AM CDT FRI OCT 4 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 414 AM CDT FRI OCT 4 2013
THE NEXT 24 HOURS WILL BE A TALE OF TWO AIR MASSES, ONE MORE COMMON
DURING MID-SUMMER AND THE OTHER MORE LIKE LATE FALL. MUCH BETTER
AGREEMENT BETWEEN THE MODELS ON TIMING OF THE COLD FRONT AS WELL AS
THE PLACEMENT OF THE UPPER LEVEL TROUGH LENDS TO A MORE CONFIDENT
FORECAST AND INCREASE IN POPS WITH THE FRONTAL BOUNDARY.
FOR TODAY A STRONG UPPER TROUGH OVER THE GREAT BASIN CENTERED JUST
EAST OF SLC WILL LIFT NORTHEAST AND INTO THE NORTHERN AND CENTRAL
PLAINS BY SATURDAY. INCREASING DOWNSTREAM PRESSURE FALLS HAVE
ALREADY INDUCED A SURFACE LOW OVER NORTHWEST KS WHICH WILL DEEPEN
AND LIKEWISE TRACK NORTHEAST AS THE INCREASING DYNAMICS ALOFT
OVERSPREAD THE PLAINS. A LARGE WARM SECTOR EXISTS EAST OF THE
CENTRAL ROCKIES WITH AN IMPRESSIVE SOUTHWESTERLY LOW LEVEL JET IN
EXCESS OF 50KTS EXTENDING THROUGH OK, KS AND WESTERN MO. A NARROW
BAND OF SCATTERED ELEVATED CONVECTION HAS FORMED AS THE RIGHT REAR
QUAD OF A 70KT WIND MAX AT 200MB ENCOUNTERS AN AXIS OF MLCAPES
AROUND 1000 J/KG ALIGNED NEAR THE LOW LEVEL JET AXIS. EARLIER
VERSIONS OF THE HRRR AND THE 00Z NAM DID A GOOD JOB OF FORECASTING
THIS ACTIVITY. EXPECT THIS CONVECTION TO SPREAD ACROSS NORTHWEST MO
AND NORTHEAST KS THIS MORNING BEFORE WEAKENING TOWARDS THE NOON
HOUR. THE AFTERNOON HOURS SHOULD BE MAINLY DRY EXCEPT FOR LATE IN
THE DAY OVER NORTHWEST MO. TEMPERATURES WILL BE IMPACTED BY THE
INCREASING MID LEVEL CLOUD COVER THIS MORNING AND THE CONVECTION
OVER NORTHWEST MO. HOWEVER, SHOULD SEE CLOUDS SCATTER OUT THIS
AFTERNOON AND ALLOW GOOD MIXING TO REACH HIGHS WELL INTO THE 80S.
THE WEATHER WILL BECOME QUITE ACTIVE THIS EVENING AS A CONVECTION
RAPIDLY FORMS ALONG A COLD FRONT OVER KS AND SOUTHEAST NE. THIS
BOUNDARY IS ATTACHED TO THE LOW PRESSURE CENTER AND WILL SWING
EASTWARD THROUGH THE CWA. GIVEN A MODERATE TO HIGHLY UNSTABLE
AIRMASS WITH OVER 2000 J/KG OF MLCAPE PLUS THE ABOVE NOTED H8 JET
AND STEEPENING MID LEVEL LAPSE RATES DUE TO COLD AIR ALOFT
OVERSPREADING THE REGION, THE CAP NOW IN PLACE WILL BE LIFTED
ALLOWING FOR RAPID DEVELOPMENT OF CONVECTION ALONG THE FRONTAL
BOUNDARY. EXPECT THIS ACTIVITY TO FORM OVER EASTERN KS AND SOUTHEAST
NE BY LATE AFTERNOON AND ENTER THE FAR NORTHWEST CWA AROUND 00Z.
SEVERE STORMS WILL BE POSSIBLE THIS EVENING MAINLY WEST OF THE I-35
CORRIDOR WITH LARGE HAIL AND DAMAGING WINDS INITIALLY AND AS THE
SQUALL LINE MATURES EVOLVING INTO A HIGH WIND THREAT. WITH
PRECIPITABLE WATER VALUES PROGGED CLOSE TO TWO STANDARD DEVIATIONS
ABOVE NORMAL ANY TRAINING CELLS WILL PRODUCE VERY HEAVY RAINFALL.
THIS MAY BE ESPECIALLY TRUE AFTER MIDNIGHT AS THE NAM HINTS AT POST
FRONTAL ELEVATED CONVECTION FORMING DUE TO INCREASING FRONTOGENESIS
WITHIN THE 850-750MB LAYER.
WHILE THE COLD FRONT IS EXPECTED TO CLEAR THE CWA BY SATURDAY
MORNING THE POST FRONTAL STRATIFORM RAIN WITH EMBEDDED THUNDER WILL
LIKELY LINGER THROUGH SATURDAY MORNING OVER THE EASTERN HALF OF THE
CWA. A MAJOR INFLUX OF COLD AIR WILL BE USHERED INTO THE CWA ON
GUSTY WESTERLY WINDS. EVEN WITH CLEARING SKIES THE COLD AIR
ADVECTION WILL OVERWHELM WHAT LITTLE WARMING THE SUN WILL PROVIDE.
AS SUCH TEMPERATURES WILL STRUGGLE TO WARM MUCH PAST 60 OVER THE
WESTERN HALF OF THE CWA. SATURDAY NIGHT PROMISES A NEED TO TURN ON
YOUR FURNACE AS DEEP COLD AIR ADVECTION CONTINUES WITH H8 TEMPERATURES
AROUND 0C POSSIBLE. SHOULD SEE SOME LOWS FALL INTO THE UPPER 30S
ACROSS NORTHERN MO.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 414 AM CDT FRI OCT 4 2013
MODEL DIFFERENCES IN THE BEGINNING OF THE EXTENDED PERIOD WILL MAKE
FOR A TRICKY FORECAST ON SUNDAY. THE ASSOCIATED UPPER LEVEL TROUGH,
THAT WILL BE RESPONSIBLE FOR DRIVING A COLD FRONT THROUGH THE AREA
FRIDAY NIGHT INTO SATURDAY MORNING, WILL DEVELOP A CUT OFF LOW IN
THE BASE OF THE TROUGH. THIS UPPER LOW WILL BE A SLOW MOVER AND BY
SUNDAY IS EXPECTED TO BE MOVING NORTH OF THE CWA. HOWEVER, MODELS
ARE DIFFERENT AS TO THE PLACEMENT OF THE LOW. THE EC AND GFS
ENSEMBLE MEAN ARE THE SLOWEST AND FURTHEST SOUTH TAKING THE UPPER
LOW ACROSS IOWA ON THE DAY SUNDAY. THE OPERATIONAL GFS AND GEM ARE
FURTHER NORTH AND MORE PROGRESSIVE WITH THE UPPER LOW. THE GEM AND
OPERATIONAL GFS WOULD LEAD TO A DRY AND SLIGHTLY WARMER SOLUTION
WHEREAS, THE GFS ENSEMBLE AND EC SOLUTION WOULD BE COOLER WITH EVEN
A CHANCE FOR SOME LIGHT PRECIPITATION ACROSS NORTHERN MISSOURI. FOR
NOW, SIDED WITH THE ALLBLEND WHICH IS A COMPROMISE SOLUTION IN
KEEPING CONDITIONS DRY WITH HIGHS IN THE UPPER 50 AND LOWER 60S. AS
SURFACE HIGH PRESSURE BUILDS IN SUNDAY NIGHT TEMPERATURES WILL
BOTTOM OUT IN THE LOWER 40S.
BEYOND SUNDAY, THE GENERAL TREND AMONGST MODELS IS SIMILAR IN
KEEPING CONDITIONS DRY WITH A WARMING TREND. MONDAY WILL BE A
TRANSITIONAL DAY WITH NORTHWEST FLOW ALOFT BEHIND THE DEPARTING
UPPER LEVEL SYSTEM. A RETURN TO SOUTHWESTERLY FLOW AND PLENTIFUL
SUNSHINE SHOULD ALLOW HIGHS TO WARM INTO THE MID 60S TO NEAR 70.
TUESDAY, AN UPPER LEVEL RIDGE WILL BEGIN TO BUILD INTO THE AREA IN
RESPONSE TO AN UPPER LEVEL TROUGH DIGGING SOUTHWARD DOWN THE WESTERN
CONUS. THIS UPPER LEVEL RIDGE IS EXPECTED TO DOMINATE THE AREA AS
WELL AS MUCH OF THE EASTERN HALF OF THE CONUS THROUGH THURSDAY.
HIGHS WILL WARM THROUGH THE MIDDLE PART OF THE WEEK WITH HIGHS IN
THE MID TO UPPER 70S BY THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY MORNING)
ISSUED AT 428 AM CDT FRI OCT 4 2013
HAVE UPDATED THE KSTJ FORECAST TO ACCOUNT FOR THE BAND OF SCATTERED
CONVECTION WHICH HAS FORMED OVER CENTRAL KS. A COUPLE OF THE SHORT
TERM CONVECTIVE ALLOWING MODELS HAD PICKED UP ON THIS DEVELOPMENT
BEFORE IT FORMED AND GIVEN THE LATEST RADAR AND SATELLITE TRENDS THIS
ACTIVITY WILL TRACK INTO NORTHWEST MO THIS MORNING. THE CONVECTION
WILL LIKELY REMAIN HIGH-BASED BUT MVFR VISIBILITIES MAY MATERIALIZE
DUE TO THE HEAVY RAINS ASSOCIATED WITH THE HIGHLY CONCENTRATED
REFLECTIVITIES.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...73
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
432 AM CDT Fri Oct 4 2013
.SHORT TERM...(Today through Saturday)
Issued at 414 AM CDT FRI OCT 4 2013
The next 48 hours will be a tale of two air masses, one more common
during mid-summer and the other more like late Fall. Much better
agreement between the models on timing of the cold front as well as
the placement of the upper level trough lends to a more confident
forecast and increase in PoPs with the frontal boundary.
For today a strong upper trough over the Great Basin centered just
east of SLC will lift northeast and into the Northern and Central
Plains by Saturday. Increasing downstream pressure falls have
already induced a surface low over northwest KS which will deepen
and likewise track northeast as the increasing dynamics aloft
overspread the Plains. A large warm sector exists east of the
Central Rockies with an impressive southwesterly low level jet in
excess of 50kts extending through OK, KS and western MO. A narrow
band of scattered elevated convection has formed as the right rear
quad of a 70kt wind max at 200mb encounters an axis of MLCAPES
around 1000 J/kg aligned near the low level jet axis. Earlier
versions of the HRRR and the 00Z NAM did a good job of forecasting
this activity. Expect this convection to spread across northwest MO
and northeast KS this morning before weakening towards the noon
hour. The afternoon hours should be mainly dry except for late in
the day over northwest MO. Temperatures will be impacted by the
increasing mid level cloud cover this morning and the convection
over northwest MO. However, should see clouds scatter out this
afternoon and allow good mixing to reach highs well into the 80s.
The weather will become quite active this evening as a convection
rapidly forms along a cold front over KS and southeast NE. This
boundary is attached to the low pressure center and will swing
eastward through the CWA. Given a moderate to highly unstable
airmass with over 2000 J/kg of MLCAPE plus the above noted h8 jet
and steepening mid level lapse rates due to cold air aloft
overspreading the region, the cap now in place will be lifted
allowing for rapid development of convection along the frontal
boundary. Expect this activity to form over eastern KS and southeast
NE by late afternoon and enter the far northwest CWA around 00Z.
Severe storms will be possible this evening mainly west of the I-35
corridor with large hail and damaging winds initially and as the
squall line matures evolving into a high wind threat. With
precipitable water values progged close to two standard deviations
above normal any training cells will produce very heavy rainfall.
This may be especially true after midnight as the NAM hints at post
frontal elevated convection forming due to increasing frontogenesis
within the 850-750mb layer.
While the cold front is expected to clear the CWA by Saturday
morning the post frontal stratiform rain with embedded thunder will
likely linger through Saturday morning over the eastern half of the
CWA. A major influx of cold air will be ushered into the CWA on
gusty westerly winds. Even with clearing skies the cold air
advection will overwhelm what little warming the sun will provide.
As such temperatures will struggle to warm much past 60 over the
western half of the CWA. Saturday night promises a need to turn on
your furnace as deep cold air advection continues with h8 temperatures
around 0C possible. Should see some lows fall into the upper 30s
across northern MO.
.LONG TERM...(Sunday through Thursday)
Issued at 414 AM CDT FRI OCT 4 2013
Model differences in the beginning of the extended period will make
for a tricky forecast on Sunday. The associated upper level trough,
that will be responsible for driving a cold front through the area
Friday night into Saturday morning, will develop a cut off low in
the base of the trough. This upper low will be a slow mover and by
Sunday is expected to be moving north of the CWA. However, models
are different as to the placement of the low. The EC and GFS
ensemble mean are the slowest and furthest south taking the upper
low across Iowa on the day Sunday. The operational GFS and GEM are
further north and more progressive with the upper low. The GEM and
operational GFS would lead to a dry and slightly warmer solution
whereas, the GFS ensemble and EC solution would be cooler with even
a chance for some light precipitation across northern Missouri. for
now, sided with the ALLBlend which is a compromise solution in
keeping conditions dry with highs in the upper 50 and lower 60s. As
surface high pressure builds in Sunday night temperatures will
bottom out in the lower 40s.
Beyond Sunday, the general trend amongst models is similar in
keeping conditions dry with a warming trend. Monday will be a
transitional day with northwest flow aloft behind the departing
upper level system. A return to southwesterly flow and plentiful
sunshine should allow highs to warm into the mid 60s to near 70.
Tuesday, an upper level ridge will begin to build into the area in
response to an upper level trough digging southward down the western
CONUS. This upper level ridge is expected to dominate the area as
well as much of the eastern half of the CONUS through Thursday.
Highs will warm through the middle part of the week with highs in
the mid to upper 70s by Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Morning)
Issued at 428 AM CDT FRI OCT 4 2013
Have updated the KSTJ forecast to account for the band of scattered
convection which has formed over central KS. A couple of the short
term convective allowing models had picked up on this development
before it formed and given the latest radar and satellite trends this
activity will track into northwest MO this morning. The convection
will likely remain high-based but MVFR visibilities may materialize
due to the heavy rains associated with the highly concentrated
reflectivities.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...73
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
418 AM CDT Fri Oct 4 2013
.SHORT TERM...(Today through Saturday)
Issued at 414 AM CDT FRI OCT 4 2013
The next 48 hours will be a tale of two airmasses, one more common
during mid-summer and the other more like late Fall. Much better
agreement between the models on timing of the cold front as well as
the placement of the upper level trough lends to a more confident
forecast and increase in PoPs with the frontal boundary.
For today a strong upper trough over the Great Basin centered just
east of SLC will lift northeast and into the Northern and Central
Plains by Saturday. Increasing downstream pressure falls have
already induced a surface low over northwest KS which will deepen
and likewise track northeast as the increasing dynamics aloft
overspread the Plains. A large warm sector exists east of the
Central Rockies with an impressive southwesterly low level jet in
excess of 50kts extending through OK, KS and western MO. A narrow
band of scattered elevated convection has formed as the right rear
quad of a 70kt wind max at 200mb encounters an axis of MLCAPES
around 1000 J/kg aligned near the low level jet axis. Earlier
versions of the HRRR and the 00Z NAM did a good job of forecasting
this activity. Expect this convection to spread across northwest MO
and northeast KS this morning before weakening towards the noon
hour. The afternoon hours should be mainly dry except for late in
the day over northwest MO. Temperatures will be impacted by the
increasing mid level cloud cover this morning and the convection
over northwest MO. However, should see clouds scatter out this
afternoon and allow good mixing to reach highs well into the 80s.
The weather will become quite active this evening as a convection
rapidly forms along a cold front over KS and southeast NE. This
boundary is attached to the low pressure center and will swing
eastward through the CWA. Given a moderate to highly unstable
airmass with over 2000 J/kg of MLCAPE plus the above noted h8 jet
and steepening mid level lapse rates due to cold air aloft
overspreading the region, the cap now in place will be lifted
allowing for rapid development of convection along the frontal
boundary. Expect this activity to form over eastern KS and southeast
NE by late afternoon and enter the far northwest CWA around 00Z.
Severe storms will be possible this evening mainly west of the I-35
corridor with large hail and damaging winds initially and as the
squall line matures evolving into a high wind threat. With
precipitable water values progged close to two standard deviations
above normal any training cells will produce very heavy rainfall.
This may be especially true after midnight as the NAM hints at post
frontal elevated convection forming due to increasing frontogenesis
within the 850-750mb layer.
While the cold front is expected to clear the CWA by Saturday
morning the post frontal stratiform rain with embedded thunder will
likely linger through Saturday morning over the eastern half of the
CWA. A major influx of cold air will be ushered into the CWA on
gusty westerly winds. Even with clearing skies the cold air
advection will overwhelm what little warming the sun will provide.
As such temperatures will struggle to warm much past 60 over the
western half of the CWA. Saturday night promises a need to turn on
your furnace as deep cold air advection continues with h8 temperatures
around 0C possible. Should see some lows fall into the upper 30s
across northern MO.
.LONG TERM...(Sunday through Thursday)
Issued at 414 AM CDT FRI OCT 4 2013
Model differences in the beginning of the extended period will make
for a tricky forecast on Sunday. The associated upper level trough,
that will be responsible for driving a cold front through the area
Friday night into Saturday morning, will develop a cut off low in
the base of the trough. This upper low will be a slow mover and by
Sunday is expected to be moving north of the CWA. However, models
are different as to the placement of the low. The EC and GFS
ensemble mean are the slowest and furthest south taking the upper
low across Iowa on the day Sunday. The operational GFS and GEM are
further north and more progressive with the upper low. The GEM and
operational GFS would lead to a dry and slightly warmer solution
whereas, the GFS ensemble and EC solution would be cooler with even
a chance for some light precipitation across northern Missouri. for
now, sided with the ALLBlend which is a compromise solution in
keeping conditions dry with highs in the upper 50 and lower 60s. As
surface high pressure builds in Sunday night temperatures will
bottom out in the lower 40s.
Beyond Sunday, the general trend amongst models is similar in
keeping conditions dry with a warming trend. Monday will be a
transitional day with northwest flow aloft behind the departing
upper level system. A return to southwesterly flow and plentiful
sunshine should allow highs to warm into the mid 60s to near 70.
Tuesday, an upper level ridge will begin to build into the area in
response to an upper level trough digging southward down the western
CONUS. This upper level ridge is expected to dominate the area as
well as much of the eastern half of the CONUS through Thursday.
Highs will warm through the middle part of the week with highs in
the mid to upper 70s by Thursday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1207 AM CDT FRI OCT 4 2013
Widespread storms over Nebraska and Iowa will generally remain north
of the STJ-IRK corridor tonight and are not expected to have impacts
on the KC area. There is a slight chance for a band of showers to
develop toward sunrise near the ICT-MCI corridor, but these would be
light and of minimal impact. Chances for this are only running around
20-30 percent so did not add any mention to the TAFs for now.
Confidence is high that a line of storms will track out of eastern KS
into western MO after 00Z and quickly race into central MO overnight.
This line of storms should be moving fast enough that only a couple
of hours of thunder are expected at a given terminal.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...73
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1208 AM CDT Fri Oct 4 2013
.UPDATE...
Issued at 834 PM CDT THU OCT 3 2013
Strengthening low-level jet over KS and MO has led to scattered
thunderstorm development over its nose over southern parts of
Nebraska and Iowa. This region will be the primary focus for
thunderstorm development tonight as the LLJ continues to strengthen
and isentropic ascent increases. RAP and NAM bring some convergence at
the nose of this jet a bit further south into far northern MO later
this evening, and it wouldn`t be surprising to see a few cells make
it into northern parts of the forecast area through midnight.
However, the window for thunderstorm development should end shortly
after midnight as a strong EML evident on the 00Z TOP RAOB begins to
overspread the area and cuts off any available instability.
Given MUCAPE around 1500 J/kg and modest effective shear, a few
strong storms are possible with large hail the main threat. Therefore
severe thunderstorm watch 537 has been issued through 5 AM CDT for
far northern Missouri. However given the cap that will overspread the
area after midnight, this watch may need to be expired early for
northern MO as the main severe threat pushes farther north into Iowa.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 318 PM CDT THU OCT 3 2013
20Z surface observations showed a synoptic stationary front anchored
from NW KS through eastern Nebraska into NW Iowa. A secondary warm
front, associated with reinforced convective outflow, arced southeast
from north central KS into Mid Missouri.
Strong pressure falls over ern KS/wrn MO suggest that convectively
induced wind field will erode quickly, with strong southerly flow
quickly becoming re-established over the area. This should allow
unseasonably warm/moist air over central/srn MO to spread quickly
northward this afternoon/evening, aided aloft by a developing low
level jet.
For tonight, models generally lack QPF over the area, but a closer
inspection yields rather robust isentropic lift by mid evening as the
developing low level jet ascends warm/moist air atop the retreating
warm front. Have painted an area of 20-25% POPs across the northern
half of the CWA by 03Z, with the area slowly retreating northward
overnight. Given the current boundary placement, would not be
surprised to see isolated activity initiate further south. The only
thing precluding higher POPs is the expectation that low level flow
will become more uniform over the next several hours, eliminating the
strong convergence currently in place over the srn CWA.
On Friday, very warm and humid conditions will overspread the area as
a surface low rapidly deepens from SW KS into south central Nebraska
by 00Z. Strong southerly winds approaching 30 mph will continue to
transport Gulf air into the region, promoting considerable shallow Cu
development. This may be the only thing keeping temperatures from
breaking the 90 degree mark (record for KC is 92 in 1938), which is
still not entirely out of the question.
Large scale height falls will begin to overspread the eastern Plains
by late afternoon as the mid level cyclone matures to a whopping 546
dm at 500mb. This will eliminate any mid level capping, allowing the
surface cold front/dryline to realize 2000+ J/kg of MLCAPE that will
be yielded by upper 80F temperatures and mid-upper 60F dewpoint.
Boundary parallel deep layer shear, augmented by an impressive
80-90kt 500mb jet streak, will likely result in rapid upscale growing
into a frontal squall line over eastern KS. 12Z model guidance has
jumped toward the consistent, but faster NAM-WRF, advancing the cold
front through the CWA tomorrow evening. Although better 700-500mb
flow will be focused into nrn IA/srn MN, sufficient deep layer shear
will exist over wrn MO/ern KS (mainly west of I-35) to support
damaging wind gusts as cells race off toward the northeast.
Hodographs suggest that storms may be able to remain along/ahead of
the undercutting cold front, which would certainly amplify any
embedded severe weather potential through 03Z before stabilization
occurs.
.LONG TERM...(Saturday through Thursday)
Issued at 318 PM CDT THU OCT 3 2013
Saturday - Sunday: A drastic change in conditions from those of
Friday are to be expected for the upcoming weekend. By daybreak
Saturday the cold front will have swept across much of Missouri,
with strong cold advection aloft beginning to push into the area.
Daybreak temperatures in the 40s to low 50s will struggle to climb
given the cold advection aloft and increased afternoon strato-cu.
Many areas will fail to reach 60 degrees. Some model discrepancies
appear on Sunday regarding the depth and track of the upper low
through the Midwest. The ECMWF remains slightly deeper and the
resultant slowdown in forward progression would keep higher cloud
cover over the northern CWA. The GFS/NAM both suggest a slightly
more progressive solution, keeping the majority of cloud cover north
of the CWA. Again, given existing cold air aloft, feel we`ll again
struggle to reach the lower 60s.
Monday - Thursday: The good news is that the blustery conditions of
the weekend will be short-lived as heights quickly begin to rise in
the wake of the departing upper trough. Once again, a deepening
trough in the southwestern CONUS will lead to a return of
southwesterly low-level flow aloft. With dry conditions prevailing,
temperatures are again expected to climb above normal for much of
next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1207 AM CDT FRI OCT 4 2013
Widespread storms over Nebraska and Iowa will generally remain north
of the STJ-IRK corridor tonight and are not expected to have impacts
on the KC area. There is a slight chance for a band of showers to
develop toward sunrise near the ICT-MCI corridor, but these would be
light and of minimal impact. Chances for this are only running around
20-30 percent so did not add any mention to the TAFs for now.
Confidence is high that a line of storms will track out of eastern KS
into western MO after 00Z and quickly race into central MO overnight.
This line of storms should be moving fast enough that only a couple
of hours of thunder are expected at a given terminal.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
834 PM CDT Thu Oct 3 2013
.UPDATE...
Issued at 834 PM CDT THU OCT 3 2013
Strengthening low-level jet over KS and MO has led to scattered
thunderstorm development over its nose over southern parts of
Nebraska and Iowa. This region will be the primary focus for
thunderstorm development tonight as the LLJ continues to strengthen
and isentropic ascent increases. RAP and NAM bring some convergence at
the nose of this jet a bit further south into far northern MO later
this evening, and it wouldn`t be surprising to see a few cells make
it into northern parts of the forecast area through midnight.
However, the window for thunderstorm development should end shortly
after midnight as a strong EML evident on the 00Z TOP RAOB begins to
overspread the area and cuts off any available instability.
Given MUCAPE around 1500 J/kg and modest effective shear, a few
strong storms are possible with large hail the main threat. Therefore
severe thunderstorm watch 537 has been issued through 5 AM CDT for
far northern Missouri. However given the cap that will overspread the
area after midnight, this watch may need to be expired early for
northern MO as the main severe threat pushes farther north into Iowa.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 318 PM CDT THU OCT 3 2013
20Z surface observations showed a synoptic stationary front anchored
from NW KS through eastern Nebraska into NW Iowa. A secondary warm
front, associated with reinforced convective outflow, arced southeast
from north central KS into Mid Missouri.
Strong pressure falls over ern KS/wrn MO suggest that convectively
induced wind field will erode quickly, with strong southerly flow
quickly becoming re-established over the area. This should allow
unseasonably warm/moist air over central/srn MO to spread quickly
northward this afternoon/evening, aided aloft by a developing low
level jet.
For tonight, models generally lack QPF over the area, but a closer
inspection yields rather robust isentropic lift by mid evening as the
developing low level jet ascends warm/moist air atop the retreating
warm front. Have painted an area of 20-25% POPs across the northern
half of the CWA by 03Z, with the area slowly retreating northward
overnight. Given the current boundary placement, would not be
surprised to see isolated activity initiate further south. The only
thing precluding higher POPs is the expectation that low level flow
will become more uniform over the next several hours, eliminating the
strong convergence currently in place over the srn CWA.
On Friday, very warm and humid conditions will overspread the area as
a surface low rapidly deepens from SW KS into south central Nebraska
by 00Z. Strong southerly winds approaching 30 mph will continue to
transport Gulf air into the region, promoting considerable shallow Cu
development. This may be the only thing keeping temperatures from
breaking the 90 degree mark (record for KC is 92 in 1938), which is
still not entirely out of the question.
Large scale height falls will begin to overspread the eastern Plains
by late afternoon as the mid level cyclone matures to a whopping 546
dm at 500mb. This will eliminate any mid level capping, allowing the
surface cold front/dryline to realize 2000+ J/kg of MLCAPE that will
be yielded by upper 80F temperatures and mid-upper 60F dewpoint.
Boundary parallel deep layer shear, augmented by an impressive
80-90kt 500mb jet streak, will likely result in rapid upscale growing
into a frontal squall line over eastern KS. 12Z model guidance has
jumped toward the consistent, but faster NAM-WRF, advancing the cold
front through the CWA tomorrow evening. Although better 700-500mb
flow will be focused into nrn IA/srn MN, sufficient deep layer shear
will exist over wrn MO/ern KS (mainly west of I-35) to support
damaging wind gusts as cells race off toward the northeast.
Hodographs suggest that storms may be able to remain along/ahead of
the undercutting cold front, which would certainly amplify any
embedded severe weather potential through 03Z before stabilization
occurs.
.LONG TERM...(Saturday through Thursday)
Issued at 318 PM CDT THU OCT 3 2013
Saturday - Sunday: A drastic change in conditions from those of
Friday are to be expected for the upcoming weekend. By daybreak
Saturday the cold front will have swept across much of Missouri,
with strong cold advection aloft beginning to push into the area.
Daybreak temperatures in the 40s to low 50s will struggle to climb
given the cold advection aloft and increased afternoon strato-cu.
Many areas will fail to reach 60 degrees. Some model discrepancies
appear on Sunday regarding the depth and track of the upper low
through the Midwest. The ECMWF remains slightly deeper and the
resultant slowdown in forward progression would keep higher cloud
cover over the northern CWA. The GFS/NAM both suggest a slightly
more progressive solution, keeping the majority of cloud cover north
of the CWA. Again, given existing cold air aloft, feel we`ll again
struggle to reach the lower 60s.
Monday - Thursday: The good news is that the blustery conditions of
the weekend will be short-lived as heights quickly begin to rise in
the wake of the departing upper trough. Once again, a deepening
trough in the southwestern CONUS will lead to a return of
southwesterly low-level flow aloft. With dry conditions prevailing,
temperatures are again expected to climb above normal for much of
next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 618 PM CDT THU OCT 3 2013
Primary concern for the next 24 hours will be gusty southerly winds
at the surface, occasionally gusting to as high as 30kt tomorrow
afternoon. These winds will stay up tonight, and with winds as high
as 50 kts at 2000 ft, there will likely be some turbulence on
approach and takeoff. However no sharp changes in wind speed
direction are anticipated in the lowest 2000 feet so LLWS was not
mentioned in the TAFs.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1234 PM CDT THU OCT 3 2013
.SHORT TERM...(Today through Saturday Afternoon)
Issued at 409 AM CDT THU OCT 3 2013
Primary topics between now and Saturday deal with timing of at least
two main convective episodes with any severe threat and the marked
temperature/airmass change arriving in the post frontal environment
by Saturday.
In the very near term an MCS has evolved over southeastern NE
overnight. Initially scattered convection formed Wednesday evening
along a cold front from central NE into west central IA. A cold pool
eventually formed and has now pushed the convection southeast and
off the cold front. The HRRR has had the best handle on this
activity and will follow its lead. A south-southwesterly low level
jet over KS and OK is feeding a moderately unstable airmass into the
southern portion of the MCS to support its existence. However,
satellite imagery shows a gradual warming of cloud tops while cloud
to ground lighting strokes have seen a steady decline. All in all
expect the complex to continue a weakening trend as it moves through
northwest MO this morning where likely PoPs have been added. Warm
air advection and lift ahead of a weak mid level shortwave moving
through the CWA with another over central KS will support isolated
elevated convection over much of the CWA this morning. Again, the
latest HRRR has a good handle on the evolution of this secondary
area of convection.
Convection expected to shift out of northern MO by early afternoon
allowing temperatures to warm back into the lower and middle
80s.
Models are in general agreement on the holding the frontal boundary
nearly stationary from a developing area of low pressure over the CO
foothills through south central NE and central IA. This should allow
for scattered convection to once again form along the frontal
boundary by early this evening. Conceivable that convection could
once again threaten northwest MO overnight if another MCS forms and
moves away from the frontal boundary like tonight. Thus will contour
best PoPs over this region.
While there remains some model variability on timing of the cold
front, model consensus and trends continue to point to Friday night
as the primary period to hit PoPs hardest. Despite favorable
ingredients for severe weather a slightly slower arrival time of the
cold front into the CWA will likely limit the severe potential to
mainly far northwest MO. A moderately strong low level jet in excess
of 40kts and 0-6km shear increasing to 40-50kts and MUCAPES in
excess of 2000 J/kg will support severe storms over eastern
NE/northeast KS into western IA and far northwest MO late Friday
afternoon and evening. However, it will be difficult to maintain
the severe threat in the CWA past far northwest MO due to the rapid
drop off in instability after sunset. Should the models slow down
the cold front even more it will further negatively impact the
severe threat.
The other primary weather impact is the arrival of a significant
shot of cold air advection that will arrive with the passage of the
cold front. Saturday morning lows will likely fall into the 40s and
with cold air advection continuing through the day with blustery
northwest winds it will be difficult to warm temperatures much past
the upper 50s to lower 60s.
.LONG TERM...(Saturday Evening through Wednesday)
Issued at 409 AM CDT THU OCT 3 2013
Quiet weather conditions are expected through the extended in the
wake of the Friday/Saturday front. There is a concern for how low
temperatures may get both Sunday and Monday morning. Significantly
drier air will have moved into the region, behind the front, with
dewpoints and 20s and 30s. Models maintain a decent pressure
gradient across the area Saturday night with the surface low in the
Upper Midwest. So we should not realize very effective radiational
cooling and lows should only fall into the upper 30s and lower 40s.
The NAM however, suggest lows below freezing as its surface pressure
field is weaker with high pressure moving in. The NAM was
disregarded as it still seems too fast with it timing of features.
For Monday morning, models show high a high pressure ridge moving
through the area with winds quite a bit lighter than the previous
night. The GEM actually drops most of the forecast area to near
freezing. There remains quite a bit of variability with the surface
pressure fields though and feel temperatures in the upper 30s and
lower 40s is more reasonable at this point. But those with
agricultural and horticultural interest should monitor later
forecasts for potential frost producing temperatures.
A quick warm up back to near and above normal temperatures is
expected by the middle of the week as upper level riding replaces
the departing trough. Thickness values will increase quite a bit by
Tuesday afternoon with significant warm advection aloft. Thus,
through the end of the work week, we should see highs climb into the
upper 80s ahead of the next deep trough developing over the western
US. The best chances for precipitation from that system may move
into northwestern portions of the forecast area late Thursday.
Confidence is not very high at this point so scaled back the
initialized PoPs significantly.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1233 PM CDT THU OCT 3 2013
Thunderstorms have shifted east of the terminals and no
precipitation is expected through much of tonight. Although ceilings
have lifted to VFR for now, satellite imagery shows a bank of lower
stratus (averaging 2Kft AGL) poised to overspread the terminals in
the next hour or so. Some thinning is expected of this cloud deck,
ultimately scattering back to VFR by 21Z.
Winds have finally begun to lose the influence of the small MCS and
should slowly trend from the east-southeast back toward the
south-southeast during the afternoon hours with speeds of 8 to 12
knots.
Warm sector should rebuild across the terminals this evening, and
will need to keep an eye on the potential for low level wind shear
depending on how much the boundary layer decouples, if at all. MCI
has a tendency for higher nocturnal gusts in these situations and
this will need to be re-evaluated with the 00Z TAFs. It`s also
possible a narrow band of showers/storms could develop along the
KS/MO border prior to daybreak, but confidence too low to warrant
mention at this time.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...CDB
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
641 AM CDT Thu Oct 3 2013
.SHORT TERM...(Today through Saturday Afternoon)
Issued at 409 AM CDT THU OCT 3 2013
Primary topics between now and Saturday deal with timing of at least
two main convective episodes with any severe threat and the marked
temperature/airmass change arriving in the post frontal environment
by Saturday.
In the very near term an MCS has evolved over southeastern NE
overnight. Initially scattered convection formed Wednesday evening
along a cold front from central NE into west central IA. A cold pool
eventually formed and has now pushed the convection southeast and
off the cold front. The HRRR has had the best handle on this
activity and will follow its lead. A south-southwesterly low level
jet over KS and OK is feeding a moderately unstable airmass into the
southern portion of the MCS to support its existence. However,
satellite imagery shows a gradual warming of cloud tops while cloud
to ground lighting strokes have seen a steady decline. All in all
expect the complex to continue a weakening trend as it moves through
northwest MO this morning where likely PoPs have been added. Warm
air advection and lift ahead of a weak mid level shortwave moving
through the CWA with another over central KS will support isolated
elevated convection over much of the CWA this morning. Again, the
latest HRRR has a good handle on the evolution of this secondary
area of convection.
Convection expected to shift out of northern MO by early afternoon
allowing temperatures to warm back into the lower and middle
80s.
Models are in general agreement on the holding the frontal boundary
nearly stationary from a developing area of low pressure over the CO
foothills through south central NE and central IA. This should allow
for scattered convection to once again form along the frontal
boundary by early this evening. Conceivable that convection could
once again threaten northwest MO overnight if another MCS forms and
moves away from the frontal boundary like tonight. Thus will contour
best PoPs over this region.
While there remains some model variability on timing of the cold front
model consensus and trends continue to point to Friday night as the
primary period to hit PoPs hardest. Despite favorable ingredients
for severe weather a slightly slower arrival time of the cold front
into the CWA will likely limit the severe potential to mainly far
northwest MO. A moderately strong low level jet in excess of 40kts
and 0-6km shear increasing to 40-50kts and MUCAPES in excess of 2000
J/kg will support severe storms over eastern NE/northeast KS into
western IA and far northwest MO late Friday afternoon and evening.
However, it will be difficult to maintain the severe threat in the
CWA past far northwest MO due to the rapid drop off in instability
after sunset. Should the models slow down the cold front even more
it will further negatively impact the severe threat.
The other primary weather impact is the arrival of a significant
shot of cold air advection that will arrive with the passage of the
cold front. Saturday morning lows will likely fall into the 40s and
with cold air advection continuing through the day with blustery
northwest winds it will be difficult to warm temperatures much past
the upper 50s to lower 60s.
.LONG TERM...(Saturday Evening through Wednesday)
Issued at 409 AM CDT THU OCT 3 2013
Quiet weather conditions are expected through the extended in the
wake of the Friday/Saturday front. There is a concern for how low
temperatures may get both Sunday and Monday morning. Significantly
drier air will have moved into the region, behind the front, with
dewpoints and 20s and 30s. Models maintain a decent pressure
gradient across the area Saturday night with the surface low in the
Upper Midwest. So we should not realize very effective radiational
cooling and lows should only fall into the upper 30s and lower 40s.
The NAM however, suggest lows below freezing as its surface pressure
field is weaker with high pressure moving in. The NAM was
disregarded as it still seems too fast with it timing of features.
For Monday morning, models show high a high pressure ridge moving
through the area with winds quite a bit lighter than the previous
night. The GEM actually drops most of the forecast area to near
freezing. There remains quite a bit of variability with the surface
pressure fields though and feel temperatures in the upper 30s and
lower 40s is more reasonable at this point. But those with
agricultural and horticultural interest should monitor later
forecasts for potential frost producing temperatures.
A quick warm up back to near and above normal temperatures is
expected by the middle of the week as upper level riding replaces
the departing trough. Thickness values will increase quite a bit by
Tuesday afternoon with significant warm advection aloft. Thus,
through the end of the work week, we should see highs climb into the
upper 80s ahead of the next deep trough developing over the western
US. The best chances for precipitation from that system may move
into northwestern portions of the forecast area late Thursday.
Confidence is not very high at this point so scaled back the
initialized PoPs significantly.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 640 AM CDT THU OCT 3 2013
A weakening mesoscale convective system tracking ese through
northwest MO and northeast KS may hold together long enough to
briefly affect all 3 terminals this morning with showers and some
thunder and a temporary wind shift to the north. Stratiform rain
shield behind the initial band of thunderstorms will likely result
in MVFR ceilings for a few hours before they improve.
Strong winds aloft above 2k feet will mix down to the surface this
afternoon resulting in gusts above 20kts. The pressure gradient will
remain fairly tight through tonight so winds will stay up all night
with occasional gusts. While conditions tonight may be similar to
what we are seeing currently there is enough uncertainty in the
models to keep mention of rain out of the forecast but plenty of time
to add it to future forecasts.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...CDB
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
409 AM CDT Thu Oct 3 2013
.SHORT TERM...(Today through Saturday Afternoon)
Issued at 409 AM CDT THU OCT 3 2013
Primary topics between now and Saturday deal with timing of at least
two main convective episodes with any severe threat and the marked
temperature/airmass change arriving in the post frontal environment
by Saturday.
In the very near term an MCS has evolved over southeastern NE
overnight. Initially scattered convection formed Wednesday evening
along a cold front from central NE into west central IA. A cold pool
eventually formed and has now pushed the convection southeast and
off the cold front. The HRRR has had the best handle on this
activity and will follow its lead. A south-southwesterly low level
jet over KS and OK is feeding a moderately unstable airmass into the
southern portion of the MCS to support its existence. However,
satellite imagery shows a gradual warming of cloud tops while cloud
to ground lighting strokes have seen a steady decline. All in all
expect the complex to continue a weakening trend as it moves through
northwest MO this morning where likely PoPs have been added. Warm
air advection and lift ahead of a weak mid level shortwave moving
through the CWA with another over central KS will support isolated
elevated convection over much of the CWA this morning. Again, the
latest HRRR has a good handle on the evolution of this secondary
area of convection.
Convection expected to shift out of northern MO by early afternoon
allowing temperatures to warm back into the lower and middle
80s.
Models are in general agreement on the holding the frontal boundary
nearly stationary from a developing area of low pressure over the CO
foothills through south central NE and central IA. This should allow
for scattered convection to once again form along the frontal
boundary by early this evening. Conceivable that convection could
once again threaten northwest MO overnight if another MCS forms and
moves away from the frontal boundary like tonight. Thus will contour
best PoPs over this region.
While there remains some model variability on timing of the cold front
model consensus and trends continue to point to Friday night as the
primary period to hit PoPs hardest. Despite favorable ingredients
for severe weather a slightly slower arrival time of the cold front
into the CWA will likely limit the severe potential to mainly far
northwest MO. A moderately strong low level jet in excess of 40kts
and 0-6km shear increasing to 40-50kts and MUCAPES in excess of 2000
J/kg will support severe storms over eastern NE/northeast KS into
western IA and far northwest MO late Friday afternoon and evening.
However, it will be difficult to maintain the severe threat in the
CWA past far northwest MO due to the rapid drop off in instability
after sunset. Should the models slow down the cold front even more
it will further negatively impact the severe threat.
The other primary weather impact is the arrival of a significant
shot of cold air advection that will arrive with the passage of the
cold front. Saturday morning lows will likely fall into the 40s and
with cold air advection continuing through the day with blustery
northwest winds it will be difficult to warm temperatures much past
the upper 50s to lower 60s.
.LONG TERM...(Saturday Evening through Wednesday)
Issued at 409 AM CDT THU OCT 3 2013
Quiet weather conditions are expected through the extended in the
wake of the Friday/Saturday front. There is a concern for how low
temperatures may get both Sunday and Monday morning. Significantly
drier air will have moved into the region, behind the front, with
dewpoints and 20s and 30s. Models maintain a decent pressure
gradient across the area Saturday night with the surface low in the
Upper Midwest. So we should not realize very effective radiational
cooling and lows should only fall into the upper 30s and lower 40s.
The NAM however, suggest lows below freezing as its surface pressure
field is weaker with high pressure moving in. The NAM was
disregarded as it still seems too fast with it timing of features.
For Monday morning, models show high a high pressure ridge moving
through the area with winds quite a bit lighter than the previous
night. The GEM actually drops most of the forecast area to near
freezing. There remains quite a bit of variability with the surface
pressure fields though and feel temperatures in the upper 30s and
lower 40s is more reasonable at this point. But those with
agricultural and horticultural interest should monitor later
forecasts for potential frost producing temperatures.
A quick warm up back to near and above normal temperatures is
expected by the middle of the week as upper level riding replaces
the departing trough. Thickness values will increase quite a bit by
Tuesday afternoon with significant warm advection aloft. Thus,
through the end of the work week, we should see highs climb into the
upper 80s ahead of the next deep trough developing over the western
US. The best chances for precipitation from that system may move
into northwestern portions of the forecast area late Thursday.
Confidence is not very high at this point so scaled back the
initialized PoPs significantly.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1145 PM CDT WED OCT 2 2013
Previous forecast appears on track. Expect to see another round of
stratus build into terminals between 08-10Z, although how low the
ceiling height becomes is in question. Do not anticipate dense fog
with surface wind field remaining 5-10kts overnight. Weak upper wave
approaching may promote scattered thunderstorms between 07-11Z near
terminals. Additionally, thunderstorm complex may drop into northwest
Missouri just prior to sunrise. Uncertainty is higher with regards to
this activity holding together and impacting terminals, potentially
after sunrise. Otherwise strengthening pressure gradient will allow
for gusty winds tomorrow.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...CDB
AVIATION...Blair
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
957 AM EDT FRI OCT 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL HANG ON OVER MUCH OF THE NORTH COUNTRY THROUGH
SATURDAY AS A FRONTAL SYSTEM REMAINS SUPPRESSED TO THE SOUTH.
CHANCES FOR SHOWERS WILL INCREASE SUNDAY AS A WARM FRONT LIFTS NORTH
ACROSS THE AREA. MORE RAIN CAN BE EXPECTED MONDAY AS LOW PRESSURE
AND ITS ASSOCIATED COLD FRONT MOVE THROUGH THE REGION. HIGH
PRESSURE THEN RETURNS FOR THE REMAINDER OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 949 AM EDT FRIDAY...HAVE INCREASED POPS ACRS OUR SOUTHERN VT
ZNS TO LIKELY/LOW CAT (70 TO 80%) AND HIGH CHC (40 TO 50%) FOR PARTS
OF THE SLV/WESTERN DACKS FOR THIS MORNING. CRNT RADAR SHOWS A BAND
OF LIGHT RAIN ACRS SOUTHERN VT WITH LIGHT RAIN BEING OBSERVED AT
VSF. IN ADDITION...ANOTHER BAND OF LIGHT RAIN IS ENTERING THE SLV
ATTM. LATEST 12Z RAP 13 SHOWS BEST 850 TO 700MB LIFT ASSOCIATED
WITH WAA AND EMBEDDED 5H VORT WL BE ACRS OUR CENTRAL/SOUTHERN CWA
THRU 16Z...BEFORE SHIFTING TO OUR EAST. MEANWHILE...PRECIP ACRS
SLV IS EXPECTED TO WEAKEN ACRS THE DACKS/WESTERN CPV BY 16Z...AS
LLVL ENVIRONMENT IS VERY DRY. OVERALL...NOT EXPECTING MUCH
QPF>0.10" THRU TODAY...WITH A GENERAL DECREASE IN AREAL COVERAGE
OF PRECIP THIS AFTN. TEMPS WL BE TRICKY AND HIGHLY DEPEND UPON
CLOUD CLOUD...WHICH WL PREVAIL MOST OF THE DAY...THEREFORE WL
TREND TEMPS DOWN SEVERAL DEGREES. THINKING U50S TO M60S MOST
LOCATIONS.
PREVIOUS DISCUSSION...
WARM FRONT STRETCHING FROM NORTHERN MICHIGAN SOUTHEAST TO JERSEY
COASTAL WATERS AT THIS TIME. THIS FRONT WILL NOT ADVANCE MUCH
FURTHER NORTH TODAY BEFORE BECOMING STATIONARY. MEANWHILE...WEAK
COLD FRONT NORTH OF THE BORDER WILL DISSIPATE AS IT DEPRESSES
SOUTH. SKIES STILL MOSTLY CLEAR ACROSS A GOOD PORTION OF FORECAST
AREA AT THIS TIME...BUT CLOUDS TO THE WEST WILL OVERSPREAD THE
REGION TODAY WITH ANY FOG DISSIPATING BY MID MORNING. SOME SHOWERS
AND EVEN A LITTLE EMBEDDED THUNDER NORTH OF THE WARM FRONT AT THIS
TIME...BUT MOST OF THIS ACTIVITY IS EXPECTED TO PASS JUST SOUTH OF
BTV CWA TODAY. ANY SHOWERS ASSOCIATED WITH COLD FRONT TO THE NORTH
SHOULD DISSIPATE. SO BEST CHANCE FOR SEEING A FEW SHOWERS TODAY
WILL BE ACROSS SOUTHERN PORTION OF FORECAST AREA...WHERE 20-30
POPS PREFERRED. TEMPERATURES WILL BE A BIT COOLER THAN PREVIOUS
DAYS...WITH HIGHS IN THE MID 60S TO AROUND 70.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS OF 441 AM EDT FRIDAY...STATIONARY BOUNDARY WILL REMAIN SOUTH OF
THE FORECAST TONIGHT THROUGH SATURDAY NIGHT. FRONT MAY ACTUALLY BE
PUSHED FURTHER SOUTH TONIGHT THROUGH SATURDAY AS HIGH PRESSURE
ANCHORED OVER HUDSON BAY NOSES SOUTHEAST INTO NEW YORK/NEW ENGLAND
WHILE FLOW ALOFT CONTINUES FROM THE WEST-NORTHWEST. ALTHOUGH
SKIES ARE EXPECTED TO BE MOSTLY CLOUDY...IT SHOULD ALSO BE MAINLY
DRY TONIGHT THROUGH SATURDAY...WITH JUST A SLIGHT CHANCE SHOWERS
SOUTH.
CONDITIONS BEGIN TO CHANGE LATER SATURDAY NIGHT INTO SUNDAY AS
UPPER RIDGE SLOWLY SHIFTS EAST. THIS IS IN RESPONSE TO DEEP UPPER
LOW APPROACHING THE WESTERN GREAT LAKES SUNDAY. AS FLOW ALOFT
BECOMES MORE SOUTHWESTERLY...THIS WILL ALLOW WARM FRONT TO FINALLY
MAKE ITS PUSH NORTHWARD. SURGE OF DEEP MOISTURE...WITH PRECIPITABLE
WATER VALUES INCREASING TO 1.50 TO 1.75 INCHES...COMBINED WITH
BAND OF FRONTOGENESIS ASSOCIATED WITH WARM FRONT WILL RESULT IN AT
LEAST LIKELY POPS FOR LATE SATURDAY NIGHT AND ESPECIALLY DURING
THE DAY ON SUNDAY. CAN`T RULE OUT EMBEDDED THUNDER OVER WESTERN
ZONES SUNDAY AFTERNOON WITH SOME WEAK INSTABILITY INDICATED.
HIGH TEMPERATURES BOTH SATURDAY AND SUNDAY WILL BE MAINLY IN THE
MID60S TO NEAR 70...WITH LOWS IN THE 40S TONIGHT AND AROUND 50
SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 352 AM EDT FRIDAY...IT TOOK AWHILE...BUT MEDIUM RANGE
GUIDANCE OF THE GFS AND ECMWF HAVE FINALLY COME INTO GOOD
AGREEMENT IN REGARDS TO A POTENT LOW PRESSURE SYSTEM MOVING OUT
OF THE ROCKIES TODAY WHICH WILL AFFECT THE NORTHEAST THIS WEEKEND
INTO EARLY NEXT WEEK. FORECASTER CONFIDENCE IS INCREASING THAT
WE`LL SEE A MODEST RAIN EVENT LATE SUNDAY NIGHT THROUGH MONDAY.
YOU CAN READ MORE ABOUT THE EVOLUTION OF THIS SYSTEM THROUGH THE
WEEKEND IN THE SHORT TERM SECTION ABOVE...BUT THE SYNOPTIC SETUP TO
START THE EXTENDED PERIOD SUNDAY NIGHT WILL FEATURE A DEEP CLOSED
LOW SHIFTING NORTHEAST INTO THE GREAT LAKES REGION...WHILE AN UPPER
TROUGH ACROSS CENTRAL CANADA DIGS SOUTHEASTWARD TOWARDS THE
INTERNATIONAL BORDER. THESE TWO FEATURES EVENTUALLY PHASE TOGETHER
BY MIDDAY MONDAY WITH THE ATTENDING SURFACE WARM FRONT SHIFTING
NORTH OF THE BTV CWA SUNDAY NIGHT...AND THE COLD FRONT SWEEPING
THROUGH ON MONDAY. FOR SUNDAY NIGHT...HAVE BACKED OFF POPS A BIT AS
STRONG SOUTH/SOUTHWESTERLY FLOW IN THE WARM SECTOR SHOULD KEEP MUCH
OF THE AREA DRY...WITH THE EXCEPTION BEING ACROSS THE ST. LAWRENCE
VALLEY WHERE SHOWERS WILL BE LIKELY CLOSER TO THE COLD FRONT. ANOMALOUSLY
HIGH PWATS FOR OCTOBER BETWEEN 1.50 AND 1.75" ON THE NOSE OF A
STRONG 50KT 850MB SOUTHWESTERLY JET WILL ENHANCE DEEP LAYER LIFT
ALONG THE COLD FRONT LATE SUNDAY NIGHT THROUGH MONDAY AS IT TRACKS
ACROSS THE FORECAST AREA AND THUS...HAVE CONTINUED THE IDEA OF
LIKELY POPS FOR THIS TIME RANGE. ALSO ADDING MOISTURE INTO THE MIX
WILL BE THE REMNANTS OF TROPICAL STORM KAREN WHICH GETS ABSORBED
INTO THE UPPER FLOW DURING THIS TIME AS WELL. LATEST RUNS OF THE GFS
AND ECMWF DIFFER ONLY SLIGHTLY ON TIMING OF THE COLD FROPA...WITH
THE ECMWF LAGGING SLIGHTLY BEHIND. WITH THE RECENT BETTER
CONSISTENCY OF THE GFS AND CONTINUED TO LEAN TOWARDS THAT
SOLUTION...WHICH PUSHES THE FRONT EAST OF THE CONNECTICUT RIVER
VALLEY BY 00Z TUESDAY AS SURFACE HIGH PRESSURE BEGINS TO BUILD IN
FROM THE WEST. PARTLY TO MOSTLY CLOUDY SKIES PERSIST THROUGH MUCH OF
TUESDAY ON NORTHWEST UPPER FLOW...BUT BY TUESDAY NIGHT RIDGING ALOFT
BUILDS IN AND HIGH PRESSURE SHOULD DOMINATE THE NORTH COUNTRY`S
WEATHER THROUGH THE REMAINDER OF THE WEEK.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
THROUGH 12Z SATURDAY...OUTSIDE OF SOME LINGERING FOG AT KSLK AND
KMPV THROUGH 14Z...GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH
THE PERIOD WITH MID CLOUDS FROM 5-10 KFT STREAMING ACROSS THE
AREA. COULD SEE A FEW SHOWERS MAINLY ACROSS SOUTHERN VT AND
NORTHERN NEW YORK...BUT SHOULDN`T IMPACT FLIGHT CONDITIONS. AFTER
00Z WHEN CIGS LOWER FURTHER TO 4-6 KFT BUT SHOULD REMAIN VFR.
WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...
12Z SATURDAY THROUGH 00Z SUNDAY...MAINLY VFR THOUGH CEILINGS WILL
CONTINUE TO LOWER THRU THE PERIOD. SLIGHT CHANCE FOR SHOWERS.
00Z SUNDAY THROUGH 00Z MONDAY...MAINLY VFR WITH INCREASING CHANCES
FOR MVFR RAIN SHOWERS AS A LOW PRESSURE SYSTEM APPROACHES FROM THE
WEST...ESPECIALLY ACROSS NORTHERN NEW YORK.
00Z MONDAY THROUGH 00Z TUESDAY...MVFR RAIN SHOWERS LIKELY AS A
COLD FRONT MOVES THROUGH THE REGION.
00Z TUESDAY THROUGH 00Z WEDNESDAY...VFR UNDER HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS/TABER
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1007 AM EDT FRI OCT 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED OVER THE REGION THROUGH SATURDAY.
A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY. THE FRONT
COMBINED WITH THE REMNANTS OF TROPICAL STORM KAREN ARE EXPECTED TO
AFFECT CENTRAL NORTH CAROLINA LATE SUNDAY THROUGH EARLY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1007 AM FRIDAY...
WATER VAPOR IMAGERY SHOWED A MODEST MID-LEVEL SHORTWAVE MOVING
ACROSS CENTRAL NORTH CAROLINA BUT WITH DRY AIR ALOFT. AT THE
SURFACE...THE PIEDMONT TROUGH IS IN PLACE...WITH DEW POINTS IN THE
60S. DESPITE THE AVAILABLE LOW-LEVEL MOISTURE AND MOISTURE AT 850MB
ON THE 12Z UPPER-AIR ANALYSIS...DRY AIR ALOFT AND CAPPING SHOULD
PRECLUDE DEEP CONVECTION. THE AMDAR SOUNDINGS EARLY THIS MORNING AT
BOTH GSO AND RDU COMPARED VERY WELL WITH THE RAP FORECAST SOUNDINGS
AT THE SAME TIME...SHOWING SOME COOLING THAT TOOK PLACE ALOFT AROUND
700MB BUT STILL WITH ENOUGH OF A CAP...AND VERY MODEST WARMING
BEHIND THE MID-LEVEL SHORTWAVE FORECAST THIS AFTERNOON...THAT THE
CHANCES FOR ANY SHOWERS APPEAR PRETTY REMOTE. ALTHOUGH NAM MOS
GUIDANCE HAS LOW 20S CHANCES FOR SHOWERS AT KGSO AND KTDF...ALL
OTHER GUIDANCE IS DRY...AND THE LATEST HRRR WRF IS DRY AS WELL.
COULD BE A FEW CLOUDS DRIFTING IN FROM THE WEST AND NORTHWEST DUE TO
SOME DEEPER CONVECTION IN DIRECT VICINITY OF THE HIGHER ELEVATIONS
LATE IN THE DAY...BUT OTHERWISE...CONSIDERABLE SUNSHINE EXPECTED
THIS AFTERNOON UNDER 700MB SUBSIDENCE. MLCAPE BARELY REGISTERS...
WITH A MODIFIED KGSO SOUNDING SHOWING AN MLCAPE IN LOW DOUBLE
FIGURES. HIGH TEMPERATURES WILL REMAIN IN THE MID TO UPPER 80S...IN
CONJUNCTION WITH 1000-850MB THICKNESSES WHICH COINCIDE WELL WITH MOS
GUIDANCE HIGHS...ALONG WITH PERSISTENCE FROM THURSDAY. -DJF
TONIGHT...LOW LEVEL SLY FLOW WILL ADVECT MOISTURE INTO THE REGION.
THIS WILL BE EVIDENT IN SFC DEWPOINTS NEAR 60-LOWER 60S. WITH
MAINLY CLEAR SKIES ALOFT AND A LIGHT-NEAR CALM WIND REGIME...MAY SEE
AREAS OF FOG DEVELOP WELL AFTER MIDNIGHT. MIN TEMPS UPPER 50S TO
LOWER 60S. -WSS
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 314 AM FRIDAY...
SATURDAY...MID-UPPER LEVEL RIDGE OVER THE SE U.S. AND A SFC HIGH
ANCHORED OFFSHORE WILL RESULT IN ANOTHER MOSTLY SUNNY AND WARM DAY.
THICKNESSES STEADY IN THE 1410-1415M SO EXPECT SIMILAR HIGHS TEMPS
COMPARED TO TODAY....MID-UPPER 80S (POSSIBLY 90 IN THE SANDHILLS).
WITH SFC DEWPOINTS IN THE LOWER 60S...IT WILL START FEEL A BIT
UNCOMFORTABLE TO MOST FOLKS.
BY SATURDAY NIGHT...T.C. KAREN WILL BE LURKING OFF THE NORTHERN GULF
OF MEXICO COAST. MEANWHILE A DEEP UPPER LEVEL LOW WILL BE OVER THE
CENTRAL PLAINS. THESE WEATHER FEATURES WILL SERVE TO WEAKEN THE
UPPER LEVEL RIDGE OVER THE SE U.S. THIS PROCESS WILL ALLOW LOW AND
UPPER LEVEL MOISTURE TO INCREASE ACROSS CENTRAL NC SATURDAY NIGHT
INTO SUNDAY. WITH SFC DEWPOINTS SOLIDLY IN THE LOWER 60S AND SKIES
MOSTLY CLEAR TO START...AREAS OF FOG SHOULD DEVELOP ONCE AGAIN. MIN
TEMPS MAINLY NEAR 60-LOWER 60S.
SUNDAY...EXPECT TO SEE AN INCREASE IN CLOUDINESS AS MID-UPPER LEVEL
WINDS BACK IN RESPONSE TO THE EWD ADVANCING UPPER LEVEL LOW MOVING
INTO THE WESTERN GREAT LAKES. THIS WEATHER SYSTEM WILL ALSO CAUSE
T.C. KAREN TO LIFT NEWD INTO THE SE U.S. LATE SUNDAY-SUNDAY NIGHT.
THE AIR MASS OVER CENTRAL NC WILL QUICKLY BECOME MOISTURE
LADEN...ESPECIALLY IN THE WEST. INCREASING DIVERGENCE ALOFT COUPLED
WITH WEAK ISENTROPIC UPGLIDE WILL SUPPORT THE DEVELOPMENT OF A FEW
SHOWERS LATE IN THE DAY...MAINLY OVER THE SW THIRD OF THE FORECAST
AREA.
EXTENT/THICKNESS OF CLOUD COVER BY SUNDAY AFTERNOON WILL PLAY A ROLE
IN AFTERNOON TEMPS. BELIEVE THAT THERE WILL BE ENOUGH PARTIAL SUN
SUNDAY AFTERNOON TO WARM TEMPS BACK INTO THE MID 80S OVER MOST OF
THE REGION.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 235 AM FRIDAY...
...KAREN`S REMNANTS WILL AFFECT NC SUNDAY NIGHT THROUGH TUESDAY
MORNING...
MODEL SOLUTIONS CONCERNING FINER DETAILS OF THE TRACK OF TROPICAL
CYCLONE KAREN AND ITS INTERACTION WITH AN APPROACHING COLD FRONT ARE
STILL ON THE LOWER END OF THE CONFIDENCE SCALE. ON THE OTHER
HAND...WHILE IT IS TOO EARLY TO PINPOINT A NARROW TIME WINDOW OF
HEAVY RAIN...A SIGNIFICANT AND WIDESPREAD BENEFICIAL RAIN EVENT
APPEARS LIKELY AS THE TROPICAL MOISTURE PLUME FROM KAREN SPREADS
INTO THE WEST SUNDAY AFTERNOON/EVENING...AND OVER MOST OF CENTRAL
NORTH CAROLINA BY MONDAY MORNING. WIDESPREAD RAINFALL AMOUNTS OF >1
INCH ARE A GOOD BET...AND A STRIPE OF 2+ INCHES CAN REASONABLY BE
EXPECTED ALONG AND WEST OF THE EVENTUAL TRACK...WHICH IS NOT CERTAIN
AT THIS POINT BUT HAS A GOOD CHANCE OF BEING OVER OR JUST SKIRTING
THE CWFA. THE POTENTIAL FOR VERY HEAVY SHOWERS WITH HIGH RAINFALL
RATES AND TRAINING CELLS WOULD PRODUCE A THREAT FOR FLASH
FLOODING...WHICH WOULD BE MORE LIKELY IN MORE URBANIZED AREAS.
CHANGES TO THE FORECAST AT THIS POINT ARE TO INCREASE POPS LATER
SUNDAY NIGHT AND MONDAY...WITH A NUDGE UPWARDS IN THE AMOUNTS AS
WELL. WILL CONTINUE PROGRESSIVE TAPERING OFF OF THE PRECIP MONDAY
NIGHT...WITH LINGERING SHOWERS IN THE NORTHEAST ON TUESDAY. HIGH
TEMPS ON MONDAY AND TUESDAY WILL BE IN THE 70S...PERHAPS SOME NEAR
80 READINGS IN THE EAST MONDAY IF PRECIP SPREADS IN A LITTLE SLOWER.
MODEL DIVERGENCE IS MORE EVIDENT AS TO LATER DEVELOPMENTS DUE TO
DIFFERENCES IN THE EVOLUTION OF A MID-LATE WEEK CUTOFF LOW AND A
REX-ISH BLOCKING PATTERN. THE ECMWF AND GFS TAKE DIFFERING ROUTES TO
ARRIVE AT A RATHER SIMILAR LOOKING PATTERN. ECMWF DEVELOPS THE
CUTOFF TO THE WEST AND MEANDERS IT NORTHEAST AND NEARLY OVERHEAD...
WHILE THE GFS DEVELOPS THE CUTOFF OVER NORTHEAST NC AND RETROGRADES
IT WEST AND OVERHEAD. AT THIS EARLY JUNCTURE WILL HOLD OFF MAKING
ANY CHANGES TO THE ONGOING DRY AND SLIGHTLY BELOW SEASONABLE
FORECAST BEYOND TUESDAY AS WE AWAIT LATER MODEL CONSENSUS.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 1007 AM FRIDAY...
EXPECT VFR CONDITIONS THROUGH 06Z SATURDAY UNDER A LIGHT WIND
REGIME...MOSTLY WEST IN DIRECTION BACKING TO SOUTH OR SOUTHWEST...
THOUGH SOMEWHAT VARIABLE ESPECIALLY EARLY THIS AFTERNOON. AREAS OF
FOG ARE EXPECTED TO BE MORE COMMON ACROSS CENTRAL NC LATE TONIGHT
INTO EARLY SATURDAY MORNING...AND AGAIN LATE SATURDAY NIGHT INTO
EARLY SUNDAY. WIDESPREAD IFR-LIFR VISIBILITIES ARE HIGHLY PROBABLE.
THE FOG SHOULD LIFT AND DISSIPATE BY 15Z EACH DAY. OTHERWISE...A
CONTINUATION OF VFR CONDITIONS EXPECTED AS HIGH PRESSURE LINGERS
OVER THE REGION.
AN APPROACHING COLD FRONT COUPLED WITH THE REMNANTS OF TROPICAL
CYCLONE KAREN WILL LIKELY BRING ADVERSE AVIATION WEATHER CONDITIONS
TO CENTRAL NC...POSSIBLY BEGINNING AS EARLY AS SUNDAY EVENING...BUT
MORE LIKELY MONDAY INTO TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...DJF/WSS
SHORT TERM...WSS
LONG TERM...MLM
AVIATION...DJF/WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
736 PM EDT WED OCT 2 2013
.SYNOPSIS...
HIGH PRESSURE WILL KEEP MILD AND DRY FOR THE REMAINDER OF THE WEEK.
A COLD FRONT WILL APPROACH THE EASTERN CAROLINAS EARLY NEXT WEEK...
BRINGING THE NEXT CHANCE OF RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM WEDNESDAY...THE FORECAST IS IN GREAT SHAPE AND NO
SIGNIFICANT CHANGES ARE NEEDED THIS EVENING. MUCH LIKE WE HAVE SEEN
THE LAST TWO NIGHTS DEWPOINTS HAVE RISEN QUICKLY IN THE VERY THIN
DECOUPLED BOUNDARY LAYER SINCE THE SUN SET. MOISTURE COULD BE A
LITTLE DEEPER TONIGHT THAN THE LAST TWO NIGHTS...SO I AM
CONTEMPLATING ADDING SOME PATCHY FOG TO THE FORECAST. THE 00Z UPPER
AIR SOUNDINGS FROM MHX AND CHS MAY HELP ANSWER THAT QUESTION.
PREVIOUS DISCUSSION FROM 200 PM FOLLOWS...
HIGH PRESSURE WILL SHIFT SLOWLY EAST THROUGH TONIGHT. THE FLOW WILL
STAY MORE VARIABLE WITH A VERY WEAK PRESSURE GRADIENT BASICALLY
BEING DOMINATED BY LAND/SEA BREEZE. THEREFORE EXPECT ON SHORE FLOW
THIS AFTERNOON BECOMING OFF SHORE OVERNIGHT. THE AIR MASS WILL
CONTINUE TO MODIFY ESPECIALLY AS WINDS BEGIN TO COME AROUND WITH A
WEAK RETURN FLOW SETTING UP HEADING INTO WEDNESDAY MORNING. PLENTY
OF DRY AIR AND SUBSIDENCE REMAINS AS MID TO UPPER RIDGE STRETCHES UP
FROM THE GULF UP THROUGH THE CAROLINAS. LIMITED MOISTURE UNDERNEATH
THE SUBSIDENCE INVERSION PRODUCING AFTERNOON CU BUT OVERALL PLENTY
OF SUNSHINE. TEMPS REACHED UP INTO THE MID 80S MOST PLACES WITH
SLIGHTLY HIGHER DEWPOINT AIR MOVING INLAND WITH SEA BREEZE.
HIGH PRESSURE WILL DRIFT SLOWLY EAST THROUGH TONIGHT ALLOWING
WINDS TO START COMING AROUND AND COMBINED WITH HIGHER DEWPOINT AIR
FROM SEA BREEZE...EXPECT TEMPS TO HOLD UP A BIT MORE THAN LAST
NIGHT. OVERALL EXPECT STABLE AND DRY CONDITIONS WITH MAINLY CLEAR
SKIES AND CALM WINDS OVERNIGHT. MOISTURE PROFILES DO SHOW SOME
INCREASE IN UPPER LEVEL MOISTURE AS WINDS SHIFT AROUND TO THE W-SW
IN UPPER ATMOSPHERE...BUT THIS WILL NOT HAVE MUCH OF AN EFFECT ON
TEMPS DROPPING OUT OVERNIGHT. TEMPS WILL FALL OFF QUICKLY AS
ATMOSPHERE DECOUPLES AND CU DISSIPATES AFTER SUNSET...ENDING UP
WITH READINGS BETWEEN 55 AND 60 MOST PLACES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...A RIDGE OF HIGH PRESSURE WILL BE FIRMLY IN
PLACE AT THE SURFACE AND ALOFT THU. THE RIDGE ALOFT WILL
TEMPORARILY FLATTEN THU NIGHT AND FRI MORNING AS A MID-LEVEL
SHORTWAVE TROUGH TOPS THE RIDGE. THE RIDGE WILL THEN REASSERT
ITSELF ACROSS THE AREA DURING FRI AND FRI NIGHT. DESPITE THE
ADDITIONAL LIFT FROM A MID-LEVEL SHORTWAVE...THERE WILL BE NO
PRECIPITATION THIS PERIOD AS THE AIRMASS WILL STILL BE TOO
DRY...ESPECIALLY IN THE MID LEVELS. HOWEVER...THERE SHOULD BE MORE
CLOUD COVER THAN IN RECENT DAYS. MOISTURE PROFILES SHOW A SLIGHT
INCREASE IN THE DEPTH OF MOISTURE IN THE LOW LEVELS AND THIS MAY
ALLOW LOW LEVEL CLOUDS TO GAIN A LITTLE DEPTH...4-8 KFT. THE
SOUNDINGS AND PRECIPITABLE WATER VALUES SUGGEST A LITTLE MORE
CLOUD COVERAGE ON FRI AS COMPARED TO THU.
A SUBSIDENT FLOW WILL ALLOW MAXIMUM TEMPS TO REMAIN WELL ABOVE
NORMAL THROUGH THE PERIOD. HIGHS WILL BE IN THE MID AND UPPER 80S
BOTH DAYS. WINDS WITHIN 3000 FT OF THE SURFACE WILL BE LIGHT AND
THIS SHOULD ALLOW THE SEABREEZE TO MAKE SOME INLAND PROGRESS...
PERHAPS WORKING SLIGHTLY FURTHER INLAND ON THU AS COMPARED TO FRI.
AT ANY RATE...THE BEACHES AND NEARBY LOCATIONS WILL BE HELD TO THE
LOWER 80S FOR HIGHS BOTH DAYS. NIGHTTIME TEMPS WILL BE MUCH CLOSER
TO NORMAL...UPPER 50S TO MID 60S. THU NIGHT WILL PREDOMINANTLY BE ON
THE LOWER END OF THIS RANGE AND FRI NIGHT ON THE HIGHER END OF THIS
RANGE.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 2 PM WEDNESDAY...CONCERN FOR THE EXTENDED REVOLVES AROUND
POTENTIAL LOCAL IMPACTS FROM A STRONG UPPER TROUGH AND ITS
ASSOCIATED COLD FRONT...AND A TROPICAL DISTURBANCE CURRENTLY IN
THE CARIBBEAN SEA.
CONTINUED 5H RIDGING ACROSS THE SOUTHEAST WILL KEEP TEMPS THROUGH
THE WKND WELL ABOVE NORMAL...REACHING VALUES MORE TYPICAL OF EARLY
SEPTEMBER THAN EARLY OCTOBER. WHILE SATURDAY WILL BE A BEAUTIFUL
EARLY-FALL DAY...INCREASED MOISTURE AND CLOUD COVER WILL SOMEWHAT
TEMPER THE SENSIBLE WEATHER ON SUNDAY...AND SOME ISOLATED CONVECTION
WILL BE POSSIBLE.
BIGGER STORY BEGINS NEXT WEEK AS THE WEATHER HAS THE POTENTIAL TO
BECOME MUCH MORE UNSETTLED. STRONG 5H TROUGH DIVING THROUGH THE
MIDWEST WILL SPAWN A STRONG SURFACE LOW ACROSS THE GREAT
PLAINS...FROM WHICH A COLD FRONT WILL DRAPE...AND MOVE SLOWLY
SOUTHEAST. AT THE SAME TIME...AN AREA OF TROPICAL MOISTURE CURRENTLY
EAST OF THE YUCATAN PENINSULA WILL ORGANIZE...AND MAY BECOME A
NAMED STORM IN THE GULF OF MEXICO. HOW THESE FEATURES INTERACT WILL
HAVE SIGNIFICANT IMPACTS ON THE LOCAL WEATHER. ECMWF/CANADIAN
CONTINUE TO SHOW A WEAKER SYSTEM IN THE GULF...AND AN UPPER LOW
BEING SHEARED OFF TO THE NORTHEAST AS SUBTROPICAL RIDGE REMAINS
ENTRENCHED ACROSS THE WESTERN ATLANTIC. THIS WOULD MEAN THE AREA
WILL REMAIN MOSTLY DRY INTO TUESDAY AS THE TROPICAL MOISTURE FLOODS
WEST OF THE AREA...AND THE EASTERN CAROLINAS WOULD ONLY SEE RAIN
TUE/WED WITH THE FROPA. ON THE OTHER HAND...GFS HAS ONCE AGAIN
RETURNED TO ITS SCENARIO OF AN ANDREA-LIKE SETUP WITH A DECENT
CIRCULATION MOVING UP I-95 ON MONDAY. THIS WOULD BRING A PERIOD OF
ACTIVE WEATHER HERE...WITH MUCH MORE SIGNIFICANT RAINFALL.
ATTM...PREFER THE ECMWF/CANADIAN SOLUTIONS. THE GFS DEVELOPING A
SOUTHERN BRANCH SPLIT LOW SEEMS UNREALISTIC INTO THE SUBTROPICAL
RIDGE...WHICH HAS A TENDENCY IN ITSELF TO SUSTAIN LONGER THAN
GUIDANCE TYPICALLY SUGGESTS. ADDITIONALLY...THE ECMWF/CANADIAN HAS
BEEN MUCH MORE CONSISTENT WITH ITS EVOLUTION...AND IS FAVORED BY
WPC. THIS MEANS TEMPS REMAINING ABOVE CLIMO AS RIDGING PERSISTS
AHEAD OF THE 5H TROUGH...BUT WITH INCREASING POP THROUGH MID-WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...AS HIGH PRESSURE CONTINUES TO REIGN OVER THE
REGION...VFR IS EXPECTED THROUGH THE VALID PERIOD WITH THE EXCEPTION
OF POSSIBLE MVFR/IFR DUE TO AREAS OF FOG BEFORE SUNRISE. LIGHT WINDS
AND A THIN LAYER OF CIRRUS WILL OVERALL ALLOW FOR A DECENT
RADIATIONAL COOLING SETUP OVERNIGHT. ANTICIPATE AREAS OF FOG
DEVELOPMENT IN THE EARLY MORNING HOURS BEFORE SUNRISE...POSSIBLY
CREATING MVFR...ESPECIALLY INLAND. AFTER DAYBREAK...CONDITIONS WILL
QUICKLY IMPROVE TO VFR FOR THE REMAINDER OF THE VALID PERIOD WITH
LIGHT AND VARIABLE WINDS IN THE MORNING BECOMING SOUTHEAST AOB 10
KTS.
EXTENDED OUTLOOK...LIGHT MORNING FOG POSSIBLE EACH DAY...AND A
SLIGHT CHANCE OF SHOWERS SUNDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM WEDNESDAY...VERY FEW CHANGES ARE NEEDED TO THE MARINE
FORECAST THIS EVENING. THE SEABREEZE CIRCULATION IS SHOWN ON THE
LATEST HRRR MODEL RUNS TO HANG ON FOR A FEW MORE HOURS...MUCH LIKE
WE SAW LAST NIGHT. AFTER MIDNIGHT THE LANDBREEZE WILL TURN WIND
DIRECTIONS NORTHWESTERLY...WITH WIND SPEEDS REMAINING LIGHT.
PREVIOUS DISCUSSION FROM 200 PM FOLLOWS...
HIGH PRESSURE SHIFTING EAST WILL BE ALMOST DIRECTLY OVER THE LOCAL
WATERS BY TONIGHT WITH A WEAK RETURN FLOW SETTING UP TOWARD MORNING.
OVERALL EXPECT A VERY WEAK GRADIENT WITH LIGHT AND VARIABLE WINDS
DOMINATED BY SEA/LAND BREEZES. THEREFORE THIS AFTERNOON SEA BREEZE
NEAR SHORE WILL PRODUCE A MORE EASTERLY ON SHORE FLOW WHILE TONIGHT
WINDS WILL BECOME MORE OFFSHORE... REMAINING LESS THAN 10 KTS FOR
THE MOST PART. THIS WILL KEEP BENIGN SEAS 2 FT OR LESS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...THE SYNOPTIC FLOW WILL BE LIGHT IN THE
LOWER LEVELS OF THE ATMOSPHERE THIS PERIOD. THUS...WINDS WILL BE
LARGELY THE RESULT OF MESO-SCALE FEATURES. THE SEABREEZE IS
EXPECTED TO BE A LITTLE STRONGER ON THU THAN ON FRI AND THUS WINDS
SHOULD BE STRONGEST THU AFTERNOON AND EARLY EVE. STILL...WIND
SPEEDS ARE EXPECTED TO BE 10 KT OR LESS THROUGH THE PERIOD. SEAS
WILL BE 2 FT OR LESS...ALTHOUGH SEAS MAY BRIEFLY BUILD TO 3 FT THU
AFTERNOON AND EVE ACROSS THE OUTERMOST PORTIONS OF THE NORTHERN
WATERS.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE EXTENDING BACK FROM THE
ATLANTIC WILL MAINTAIN ITS GRIP OVER THE WATERS THROUGH THE
PERIOD...BUT WILL BE INFLUENCED BY A SLOWLY APPROACHING COLD FRONT
EARLY NEXT WEEK. WITH HIGH PRESSURE RIDGING ACROSS THE WATERS
DURING THE WKND...PRESSURE GRADIENT REMAINS WEAK...SUPPORTING
WINDS 10 KTS OR LESS...BECOMING PREDOMINANTLY FROM THE SE INTO
SUNDAY NIGHT. BY SUNDAY NIGHT...GRADIENT BEGINS TO TIGHTEN AHEAD
OF THE COLD FRONT AS THE WATERS BECOME SANDWICHED BETWEEN THE
FRONT AND THE HIGH PRESSURE...DRIVING WINDS UP TO 15 KTS FROM THE
SOUTH. SEAS INITIALLY WILL HAVE A SE SWELL COMPONENT TO THEM...BUT
WILL BECOME INCREASINGLY WIND-WAVE DOMINATED...RISING FROM 1-2 FT
SATURDAY TO AS MUCH AS 4-6 FT MONDAY. STILL A LOT OF UNCERTAINTY
MONDAY DUE TO MODEL DISCREPANCIES IN HANDLING A LOW PRESSURE
DEVELOPING IN THE GULF OF MEXICO...BUT THERE IS POTENTIAL FOR
STATEMENTS/HEADLINES MONDAY...ESPECIALLY IF THE GFS (STRONGER,
CLOSER LOW PLACEMENT) COMES TRUE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ/TRA
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...RGZ/DL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
730 PM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK TROUGH AXIS/VORT MAX EXITS THIS EVENING. MID/UPPER RIDGING
FRIDAY. MUGGY SUMMER LIKE AIR FRIDAY INTO SATURDAY. COLD FRONT
BRINGS WETTER WEATHER LATE SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
ACCORDING TO THE RAP SOLUTION THE WEAK 500 MB VORT MAX SHOULD BE
PASSING EAST OF THE MOISTURE AND LEFTOVER CONVECTION AT 23Z.
CARRIED SOME WEAKENING CONVECTION INTO NORTH CENTRAL WV THIS
EVENING.
THRU 23Z...A FEW SPOTS HAD .5 TO AN INCH OF RAIN IN SOUTHEAST
OHIO...SUCH AS IN PERRY AND MORGAN COUNTIES...ALSO SOME LOCATIONS
IN THE MID OHIO VALLEY AROUND WOOD...RITCHIE AND PLEASANTS COUNTIES.
AS A RESULT...INCREASED FOG IN THE OHIO VALLEY INCLUDING
PKB...UNI...AND HTS A THERE OVERNIGHT INTO DAWN...FIGURING ON JUST
PATCHES OF LEFTOVER CLOUDS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
DEALING WITH POTENT UPR TROF/ASSOCIATED COLD FRONT AND KAREN
MOVING OUT OF GULF DURING SHORT TERM PERIODS. TREND IN MDLS IS TO
KEEP MUCH OF WEEKEND WARM AND DRY WITH A SLOWER PROGRESSION OF UPR
TROF. AS SUCH...KEPT MOST POP FREE UNTIL SUNDAY AFTN. DID ALLOW
FOR SOME LATE AFTN LOW POPS SATURDAY IN CENTRAL AND NORTHERN MTNS
ON SOME SE UPSLOPE FLOW. CONCERNING KAREN...ALTHOUGH MDLS DIFFER
SOME ON LANDFALL...THERE IS A GENERAL AGREEMENT ON MORE OF A RIGHT
TURN ONCE INTO CAROLINAS WITH UPR TROF APPROACHING. USED LATEST
NHC TRACK AND HPC SFC PROGS FOR POPS SUNDAY AFTN AND SUNDAY NIGHT.
HAVE CATEGORICAL ENTERING SE OH LATE SUNDAY AFTN AND OVERSPREADING
REMAINDER OF AREA SUNDAY EVE WITH PROGRESSION OF COLD FRONT. FEEL
FRONT WILL CLEAR MUCH OF AREA LATE SUNDAY NIGHT...SAVE FOR PERHAPS
THE MTNS. AS SUCH ALLOW THINGS TO DRY OUT W HALF OF CWA. AS KAREN
CROSSES INTO CAROLINAS THINGS BECOME MORE UNCERTAIN TOWARD THE
MTNS BY MONDAY MORNING AND HAVE HELD SOME HIGH POPS FOR THIS AREA.
ONLY SEE A SLIVER OF INSTABILITY WITH FRONT...MOSTLY ALONG AND W
OF OH RVR LATER SUNDAY. HENCE...ONLY HAVE A FEW HRS OF THUNDER FOR
THOSE LOCALES WITH -SHRA WORDING ELSEWHERE.
FOR TEMPS...ELECTED TO ROLL ON THE HIGHER SIDE OF
GUIDANCE...ESPECIALLY FOR HIGHS SATURDAY GIVEN SE DOWNSLOPING FLOW
W OF MTNS. FEEL UPR 80S A GOOD BET ACROSS THE LOWLANDS AS RESULT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FOR THE EARLY PORTION OF THE EXTENDED PERIOD...NUMERICAL GUIDANCE IS
UNSURE OF HOW TO HANDLE KAREN PHASING INTO THE TROUGH IN THE SE US
REGION. 12Z GFS BRINGS TS KAREN FURTHER WEST THAN THE EARLIER 06Z
LINE OF THINKING. AGREEMENT DOES EXIST ON TIMING OF THE TROUGH AXIS
OVER THE OHIO RIVER VALLEY BETWEEN THE 00Z ECMWF AND 12Z GFS RUNS.
UPPED THE POPS ON DAYS 4 AND 5 WITH AT LEAST SOME MODEL CONSENSUS
GIVEN. AFTER THE SYSTEM EXITS LATE MONDAY...HIGH PRESSURE BUILDS...
HAVING A DRYING AND WARMING EFFECT ON THE REMAINDER OF THE EXTENDED.
ECMWF IS BEING A LITTLE MORE BULLISH ON STRONG UPPER RIDGING WEST
DAYS 6 AND 7.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
HAVE CONVECTION PASSING THROUGH NORTH CENTRAL WV AT 00Z INCLUDING
CKB VCNTY. 500 MB VORT MAX SHOULD BE PASSING EAST OF THAT MOISTURE
NOW...EXPECT WEAKENING TREND 01Z TO 02Z.
INCREASED COVERAGE OF FOG IN THE MID OHIO VALLEY INCLUDING
PKB...HTS...AND UNI VCNTY BASED ON LATE AFTERNOON AND EARLY EVENING
SHOWERS. THOUGH PATCHES OF OVERNIGHT CLOUDS MAY STILL AFFECT AREAL
EXTENT AND TIMING.
WITH DEW POINTS REMAINING HIGH FOR OCTOBER...SOME HAZE MAY LINGER
THROUGH 17Z FRIDAY WITH VSBY AROUND 6 MILES.
HAVE MOSTLY SCATTERED CU AFTER 15Z AT 2 TO 4 THSD FT LIFTING TO 3 TO
5 THSD FT AGL BY 21Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF FOG OVERNIGHT MAY VARY
FROM CURRENT FORECAST...DEPENDING ON CLOUD COVER.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 10/04/13
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H M L L L L L L
HTS CONSISTENCY H M M M M L L L L L L L
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H L L L L L L L
PKB CONSISTENCY H H H M M M L L L L L L
CKB CONSISTENCY H H H H H M L H H H M M
AFTER 00Z SATURDAY...
PATCHY IFR VALLEY FOG POSSIBLE AGAIN EARLY SATURDAY MORNING.
IFR POSSIBLE ALONG FRONT SUNDAY NIGHT INTO MONDAY...THEN MAY LINGER
IN MOUNTAINOUS COUNTIES MONDAY NIGHT INTO TUESDAY UNDER MID/UPPER
LEVEL LOW.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...30/26/TAX
NEAR TERM...KTB
SHORT TERM...30
LONG TERM...TAX/99
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
228 PM EDT WED OCT 2 2013
.SYNOPSIS...
SOUTHERLY FLOW ON THE BACKSIDE OF HIGH PRESSURE IN THE SOUTHERN
APPALACHIANS WILL DRAW INCREASING MOISTURE INTO THE REGION THROUGH
THURSDAY. A WARM FRONT LIFTING INTO THE GREAT LAKES REGION WILL
KEEP THIS MOIST AND UNSEASONABLY WARM AIR IN THE OHIO VALLEY
THROUGH THE END OF THE WEEK...AS WELL AS AN INCREASED THREAT FOR
SHOWERS AND THUNDERSTORMS. A STRONG COLD FRONT WILL PASS EAST
THROUGH THE REGION LATE SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW LEVEL STRATUS HAS BEEN SLOWLY WORKING ITS WAY EAST NORTHEAST
ACROSS THE AREA THIS MORNING WITH A FAIR AMOUNT OF CLOUDINESS NOW
ALONG AND NORTHWEST OF THE I-71 CORRIDOR. WITH THE SUN UP...THE
EASTWARD PUSH WILL LIKELY SLOW SO SOME OF OUR SOUTHEASTERN AREAS
WILL LIKELY REMAIN JUST PARTLY CLOUDY. WHERE THE LOWER STRATUS HAS
MOVED IN...IT SHOULD EVENTUALLY TRANSITION INTO A SCT-BKN CU FIELD
THROUGH LATE MORNING/EARLY AFTERNOON. HOW FAST THIS OCCURS WILL
HAVE AN IMPACT ON AFTERNOON HIGHS AND THE AMOUNT OF INSTABILITY WE
DEVELOP LATER THIS AFTERNOON. WILL BANK ON ENOUGH BREAKS
DEVELOPING TO STILL PUSH HIGHS INTO THE UPPER 70S TO LOWER 80S.
THE LATEST RAP IS SUGGESTING MUCAPES UP CLOSE TO 1000 J/KG BY LATE
AFTERNOON BUT THIS MAY BE A LITTLE OVERDONE DUE TO THE CLOUDINESS.
SOME WEAK ISENTROPIC LIFT WILL DEVELOP FROM THE SOUTHWEST THIS
AFTERNOON AND THIS MAY BE ENOUGH TO GENERATE A FEW SHOWERS OR AN
ISOLATED THUNDERSTORM...PRIMARILY ACROSS OUR SOUTHWESTERN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
ANY SHOWERS OR THUNDERSTORMS THAT DEVELOP IN THE DAYTIME WILL
PERSIST INTO THE EVENING HOURS AND THEN SHIFT NORTHWARD OVERNIGHT.
THIS WILL BE FOCUSED NEAREST THE WARM FRONT THAT SHOULD BE IN FAR
NORTHERN OHIO BY DAYBREAK THURSDAY.
THE WARM AND MOIST AIR BEING PUMPED IN ON SOUTHWEST WINDS WILL
ENTER INTO A CONDITIONALLY UNSTABLE AIRMASS AND ANY SMALL
VORTICITY MAXIMA IN THE SOUTHWEST FLOW ALOFT SHOULD BE ENOUGH TO
SPARK OR CONTINUE THUNDERSTORM ACTIVITY...PARTICULARLY DURING THE
DAY THURSDAY. FELT THAT THE LIKELY POPS AT DAYBREAK INTO THE
AFTERNOON THURSDAY IN THE NORTHWEST WERE OVERDONE BUT I DID NOT
SEE A VIABLE REASON TO LOWER THE CHANCE OF RAIN FOR THIS PERIOD
AND RAN WITH THE PREVIOUS FORECAST.
ALTHOUGH A RELATIVE LULL IN THE VORT MAXES MOVING THROUGH IS
BEING PROGGED THURSDAY NIGHT AND MUCH OF FRIDAY...LOW CHANCE POPS
CANNOT BE RULED OUT IN ANY LOCATION.
TEMPERATURES WILL REMAIN ABOVE NORMAL ON BOTH DAYTIME HIGHS AND
OVERNIGHT LOWS THROUGH THE PERIOD.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE PRIMARY FOCUS DURING THE LONG TERM WILL BE ON A DEEP CYCLONE
FORECAST TO DEVELOP IN THE WESTERN GREAT LAKES OVER THE
WEEKEND...AND THE ASSOCIATED COLD FRONT MOVING THROUGH THE OHIO
VALLEY. THIS FORECAST IS FURTHER COMPLICATED BY TROPICAL MOISTURE
COMING FROM THE GULF OF MEXICO.
RIDGING OVER THE SOUTHEAST STATES WILL BE IN PLACE ON FRIDAY AND
INTO SATURDAY...WITH THE ILN CWA UNDER A REGIME OF SOUTHWEST FLOW.
MOISTURE WILL GENERALLY BE SHIFTING NORTHWARD WITH THE CWA BECOMING
WARM SECTORED BY AFTERNOON...SIGNIFICANTLY LIMITING THE
PRECIPITATION CHANCES GOING INTO FRIDAY NIGHT. THIS PATTERN OF WARM
ADVECTION...WITH SLIGHT CHANCES FOR SHOWERS (AND POSSIBLY A
STORM)...WILL CONTINUE UNTIL THE COLD FRONT MOVES IN.
THE OVERALL MODEL CONSENSUS SUPPORTS A SLOWER TIMING FOR THE
FRONT...LEAVING MOST OF SATURDAY FREE OF SIGNIFICANT PRECIPITATION
CHANCES. THIS REQUIRED SOME SIGNIFICANT BUMPS UPWARD IN TEMPS ON
SATURDAY AND THE ADJACENT OVERNIGHT PERIODS.
WHILE THE TIMING OF THE FRONT HAS SLOWED WHEN LOOKING AT A BLEND OF
THE MODELS...THE INDIVIDUAL MODEL SOLUTIONS ARE MAINTAINING A VERY
WIDE ARRAY OF TIMING. NO MODEL BETTER EXEMPLIFIES THE LACK OF
CONFIDENCE IN THIS FORECAST MORE THAN THE ECMWF...WHICH DEPICTED
FRONTAL PRECIPITATION REACHING THE CWA BY SATURDAY NIGHT ON THE 00Z
RUN...AND SLOWED THE FRONT DOWN TO MONDAY MORNING ON THE 12Z RUN.
THE GFS SOLUTIONS HAVE BEEN A LITTLE MORE STEADY...WITH FRONTAL
TIMING ON SUNDAY AFTERNOON...BUT GFSE SPREADS WITH THE UPPER LOW
SUGGEST INSTABILITY IN THIS SOLUTION. THIS WILL END UP BEING A
GUARANTEED 100-POP EVENT...BUT FRUSTRATINGLY...THE TIMING CONCERNS
PRECLUDE MORE THAN 40-50 POPS FOR NOW. THE POPS HAVE BEEN TRENDED
BACK FROM THE PREVIOUS FORECAST...NOW CENTERING AROUND SUNDAY
MORNING. TIMING WILL HAVE A VERY BIG IMPACT ON THE POTENTIAL FOR
INSTABILITY...AND WHILE THE AIR MASS (SHEAR INCLUDED) WOULD SUPPORT
SOME STRONG STORMS IF THE FRONT MOVES IN AT A FAVORABLE TIME OF
DAY...THAT SCENARIO IS FAR FROM A GUARANTEE.
THE DEEP TROUGH EXTENDING FROM THE UPPER LOW WILL ACT AS A KICKER TO
WHATEVER IS COMING OUT OF THE GULF LATE IN THE WEEKEND (PERHAPS A
DEFINED TROPICAL SYSTEM). THE ARRAY OF SOLUTIONS FOR HOW THIS WILL
INTERACT WITH THE COLD FRONT OVER THE OHIO VALLEY IS SO WIDE THAT
TRYING TO FORECAST THE IMPACTS SPECIFICALLY IS NOT POSSIBLE. WITH
THAT SAID...20-30 POPS HAVE BEEN ADDED GOING INTO MONDAY AND MONDAY
NIGHT...AND MAINLY FOCUSED IN THE SOUTHEASTERN HALF OF THE CWA.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
IFR TO MVFR STRATUS HAS BEEN SLOWLY LIFTING UP INTO A VFR CU FIELD
AND EXPECT THIS TO CONTINUE THROUGH MID AFTERNOON. IT LOOKS LIKE
IT WILL BE LAST TO LIFT ALONG THE OHIO RIVER...INCLUDING AT
KCVG/KLUK. THIS HAS HELPED STABILIZE THINGS ACROSS THAT AREA SO
THINK ISOLATED TO SCATTERED SHOWERS PUSHING SLOWLY EAST ACROSS
CENTRAL KENTUCKY WILL GENERALLY REMAIN SOUTH OF THE OHIO RIVER
THROUGH THE REMAINDER OF THE AFTERNOON.
EXPECT CU TO DISSIPATE TOWARD SUNSET LEAVING MAINLY CLEAR SKIES
THIS EVENING. SOME UNCERTAINTY EXISTS AS TO HOW THINGS WILL PLAY
OUT LATER IN THE TAF PERIOD. THE 12Z NAM IS MORE AGGRESSIVE THAN
THE 12Z GFS BRINGING IN DEEPER MOISTURE AND SOME BETTER ISENTROPIC
LIFT LATE TONIGHT INTO THURSDAY MORNING AND AS A RESULT IS TRYING
TO PRODUCE MORE WIDESPREAD PCPN. WOULD THINK THIS IS OVERDONE WITH
US BEING MORE INTO THE WARM SECTOR SO WILL DOWNPLAY POPS SOMEWHAT
AND JUST ALLOW FOR A VCSH TOWARD THE END OF THE TAF PERIOD. THE
OTHER CONCERN IS THE POSSIBILITY OF STRATUS DEVELOPMENT AGAIN LATER
TONIGHT. THE MODELS DO NOT APPEAR TO BE AS MOIST AT AND BELOW 925
MB TONIGHT COMPARED TO LAST NIGHT. WE SHOULD ALSO START TO SEE
SOME HIGH AND THEN MID LEVEL CLOUDS BEGIN TO MOVE IN LATER
TONIGHT WHICH WOULD HELP MITIGATE DEVELOPMENT. AS A RESULT...WILL
KEEP CIGS VFR AND GENERALLY KEEP ANY BR TO JUST MVFR.
OUTLOOK...THUNDERSTORMS POSSIBLE SATURDAY INTO SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...HATZOS
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS TULSA OK
610 AM CDT THU OCT 3 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOR THE 12Z TAFS... VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES
THROUGHOUT THE 24 HOUR FORECAST PERIOD... WITH SKIES BECOMING
OVERCAST AT ABOUT 5K FEET. SOUTHERLY WINDS WILL BECOME GUSTY ACROSS
MOST OF THE REGION DURING THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 402 AM CDT THU OCT 3 2013/
DISCUSSION...
A FEW SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM HAVE DEVELOPED
ACROSS SOUTHEAST OKLAHOMA AND WESTERN ARKANSAS DURING THE PAST
COUPLE HOURS. THE HRRR SUGGESTS THAT CONVECTIVE COVERAGE IS LIKELY
TO WANE AROUND SUNRISE BUT THAT ISOLATED ACTIVITY WILL REMAIN
POSSIBLE THROUGH THE DAY. THUS WILL CARRY A MINIMAL POP ACROSS
NORTHWEST ARKANSAS AND FAR EASTERN OKLAHOMA TODAY.
VERY WARM AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY. THE
MODELS HAVE COME INTO MUCH BETTER AGREEMENT ON THE TIMING OF A
STRONG COLD FRONT THAT WILL MOVE ACROSS THE AREA FRIDAY NIGHT.
SHOWER AND THUNDERSTORM CHANCES WILL INCREASE NEAR AND IMMEDIATELY
BEHIND THE FRONTAL ZONE...ESPECIALLY LATE FRIDAY EVENING INTO
SATURDAY. WHILE NOT ZERO...SEVERE WEATHER POTENTIAL WILL BE
LIMITED BY THE TIMING OF THE SYSTEM ALONG WITH THE FACT THAT MUCH
OF THE CONVECTION WILL LIKELY BE POST-FRONTAL IN NATURE.
MUCH COOLER WEATHER WILL FOLLOW THE FRONT FOR THE WEEKEND WITH A
WARMING TREND THEN TAKING PLACE NEXT WEEK. IT NOW APPEARS THAT
MONDAY MORNING WILL BE THE COLDEST MORNING WE HAVE SEEN THUS FAR
THIS FALL SEASON IN MOST PLACES.
STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE DAYS WITH A
TREND TOWARDS THE COLDER GUIDANCE FOR LOWS FRIDAY NIGHT.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION
NWS TULSA OK
402 AM CDT THU OCT 3 2013
.DISCUSSION...
A FEW SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM HAVE DEVELOPED
ACROSS SOUTHEAST OKLAHOMA AND WESTERN ARKANSAS DURING THE PAST
COUPLE HOURS. THE HRRR SUGGESTS THAT CONVECTIVE COVERAGE IS LIKELY
TO WANE AROUND SUNRISE BUT THAT ISOLATED ACTIVITY WILL REMAIN
POSSIBLE THROUGH THE DAY. THUS WILL CARRY A MINIMAL POP ACROSS
NORTHWEST ARKANSAS AND FAR EASTERN OKLAHOMA TODAY.
VERY WARM AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY. THE
MODELS HAVE COME INTO MUCH BETTER AGREEMENT ON THE TIMING OF A
STRONG COLD FRONT THAT WILL MOVE ACROSS THE AREA FRIDAY NIGHT.
SHOWER AND THUNDERSTORM CHANCES WILL INCREASE NEAR AND IMMEDIATELY
BEHIND THE FRONTAL ZONE...ESPECIALLY LATE FRIDAY EVENING INTO
SATURDAY. WHILE NOT ZERO...SEVERE WEATHER POTENTIAL WILL BE
LIMITED BY THE TIMING OF THE SYSTEM ALONG WITH THE FACT THAT MUCH
OF THE CONVECTION WILL LIKELY BE POST-FRONTAL IN NATURE.
MUCH COOLER WEATHER WILL FOLLOW THE FRONT FOR THE WEEKEND WITH A
WARMING TREND THEN TAKING PLACE NEXT WEEK. IT NOW APPEARS THAT
MONDAY MORNING WILL BE THE COLDEST MORNING WE HAVE SEEN THUS FAR
THIS FALL SEASON IN MOST PLACES.
STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE DAYS WITH A
TREND TOWARDS THE COLDER GUIDANCE FOR LOWS FRIDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 90 72 90 50 / 10 10 10 70
FSM 89 70 91 62 / 20 10 10 40
MLC 89 71 90 56 / 10 10 10 50
BVO 89 70 89 48 / 10 10 10 70
FYV 85 66 86 56 / 20 10 10 40
BYV 84 66 86 58 / 20 10 10 40
MKO 89 70 90 55 / 10 10 10 70
MIO 87 70 88 52 / 10 10 10 70
F10 89 70 89 52 / 10 10 10 70
HHW 88 70 89 61 / 20 10 10 40
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...06
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION
NWS TULSA OK
1148 PM CDT WED OCT 2 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
LOCALIZED AREAS OF IFR/LIFR CONDITIONS IN FOG MAY DEVELOP
LATER TONIGHT ACROSS PARTS OF NE OKLAHOMA AND NW ARKANSAS.
THUNDERSTORMS CURRENTLY ACROSS NEBRASKA ARE EXPECTED TO
REMAIN N OF THE AREA...BUT THIS WILL BE WATCHED CLOSELY.
EXPECT CIGS TO IMPROVE THURSDAY MORNING...WITH SOUTH WINDS
BECOMING GUSTY DURING THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 905 PM CDT WED OCT 2 2013/
..UPDATE...
DISCUSSION...
SKIES HAVE CLEARED MOST OF THE REGION THIS EVENING WITH SOUTH
SOUTHEASTERLY WINDS AT 5 TO 10 MPH. OVERNIGHT TONIGHT...CLOUDS ARE
EXPECTED TO REDEVELOP OVER EASTERN OKLAHOMA AND NORTHWEST ARKANSAS
AGAIN LIKE THE PREVIOUS COUPLE OF NIGHTS. LOW CEILINGS WILL BE
POSSIBLE OVER PARTS OF THE REGION WITH SOME ISOLATED PATCHES OF
FOG...THOUGH WINDS SHOULD REMAIN UP ENOUGH TO KEEP ANY FOG
LOCALIZED. THESE CONDITIONS ALONG WITH HIGH DEWPOINTS SHOULD KEEP
LOW TEMPS TONIGHT ABOVE THE SEASONAL AVERAGE.
AN MCS HAS DEVELOPED OVER EASTERN NEBRASKA ALONG A FRONTAL
BOUNDARY. LATEST HRRR SHOWS THIS STAYING WELL TO OUR NORTH AND
NORTHEAST...WHILE GFS/NAM DEVELOP SOME PRECIP SIGNALS OVER EASTERN
OKLAHOMA AND NORTHWEST ARKANSAS LATE TONIGHT. FOR NOW WILL KEEP
THINGS DRY TONIGHT AS THESE SIGNALS COULD BE ATTRIBUTED TO
POSSIBLE LOW LEVEL CLOUD COVER. CURRENT FORECAST SEEMS TO BE
HANDLING WELL AND NO EVENING UPDATE IS PLANNED FOR NOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 70 89 71 89 / 10 10 10 10
FSM 68 88 68 90 / 10 10 10 10
MLC 69 89 71 90 / 10 10 10 10
BVO 66 89 68 89 / 10 10 10 10
FYV 63 84 65 85 / 10 10 10 10
BYV 63 84 65 86 / 10 10 10 10
MKO 68 88 69 89 / 10 10 10 10
MIO 68 88 69 89 / 10 10 10 10
F10 69 88 70 89 / 10 10 10 10
HHW 68 87 68 89 / 10 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...18
AREA FORECAST DISCUSSION
NWS TULSA OK
905 PM CDT WED OCT 2 2013
...UPDATE...
.DISCUSSION...
SKIES HAVE CLEARED MOST OF THE REGION THIS EVENING WITH SOUTH
SOUTHEASTERLY WINDS AT 5 TO 10 MPH. OVERNIGHT TONIGHT...CLOUDS ARE
EXPECTED TO REDEVELOP OVER EASTERN OKLAHOMA AND NORTHWEST ARKANSAS
AGAIN LIKE THE PREVIOUS COUPLE OF NIGHTS. LOW CEILINGS WILL BE
POSSIBLE OVER PARTS OF THE REGION WITH SOME ISOLATED PATCHES OF
FOG...THOUGH WINDS SHOULD REMAIN UP ENOUGH TO KEEP ANY FOG
LOCALIZED. THESE CONDITIONS ALONG WITH HIGH DEWPOINTS SHOULD KEEP
LOW TEMPS TONIGHT ABOVE THE SEASONAL AVERAGE.
AN MCS HAS DEVELOPED OVER EASTERN NEBRASKA ALONG A FRONTAL
BOUNDARY. LATEST HRRR SHOWS THIS STAYING WELL TO OUR NORTH AND
NORTHEAST...WHILE GFS/NAM DEVELOP SOME PRECIP SIGNALS OVER EASTERN
OKLAHOMA AND NORTHWEST ARKANSAS LATE TONIGHT. FOR NOW WILL KEEP
THINGS DRY TONIGHT AS THESE SIGNALS COULD BE ATTRIBUTED TO
POSSIBLE LOW LEVEL CLOUD COVER. CURRENT FORECAST SEEMS TO BE
HANDLING WELL AND NO EVENING UPDATE IS PLANNED FOR NOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 70 89 71 89 / 10 10 10 10
FSM 68 88 68 90 / 10 10 10 10
MLC 69 89 71 90 / 10 10 10 10
BVO 66 89 68 89 / 10 10 10 10
FYV 63 84 65 85 / 10 10 10 10
BYV 63 84 65 86 / 10 10 10 10
MKO 68 88 69 89 / 10 10 10 10
MIO 68 88 69 89 / 10 10 10 10
F10 69 88 70 89 / 10 10 10 10
HHW 68 87 68 89 / 10 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...20
AREA FORECAST DISCUSSION
NWS MEDFORD OR
838 PM PDT WED OCT 2 2013
.SHORT TERM...LIGHT SCATTERED SHOWERS ARE CONTINUING AS A
SHORTWAVE TROUGH MOVES OVER THE AREA, WITH GREATEST SHOWERS NEAR THE
COASTAL MOUNTAINS...INTO DOUGLAS COUNTY AND OVER THE CASCADES AND
SISKIYOUS. WITH COLD AIR MOVING INTO THE AREA ALOFT, SNOW LEVELS
HAVE ALSO COME DOWN TO AROUND 5000 FEET AND ARE EXPECTED TO
CONTINUE TO LOWER TONIGHT TO AROUND 4000 FEET. SHOWERS ARE MAINLY
LIGHT THOUGH SO EXPECT LITTLE SNOW EVEN AT HIGHER ELEVATIONS
EXCEPT FOR IN THE OCCASIONAL STRONGER SHOWER. COLD AIR ALOFT IS
ALSO BRINGING SOME INSTABILITY AS THIS SHORTWAVE TROUGH MOVES
OVERNIGHT. THIS EVENING, THERE HAS BEEN LIGHTNING STRIKE TO THE
NORTH JUST OFF THE CENTRAL OREGON COAST. HOWEVER MODELS CONTINUE
TO KEEP INSTABILITY NORTH OF THE CWA. SO HAVE KEPT MENTION OF ANY
THUNDERSTORMS OUT OF THE EVENING AND OVERNIGHT FORECAST. THE
SHORTWAVE IS SHIFTING INLAND THIS EVENING AND IS FORECAST TO MOVE
EAST OF THE CASCADES OVERNIGHT. SHOWER ACTIVITY IS EXPECTED TO
BECOME ISOLATED AND MAINLY OVER THE CASCADES AND OVER THE
MOUNTAINS TO THE EAST TONIGHT, ALTHOUGH A FEW SHOWERS MAY CONTINUE
OVER THE COOS AND DOUGLAS AREAS. LIGHT SHOWERS MAY LINGER INTO THE
EARLY MORNING ON THURSDAY IN EASTERN LAKE COUNTY AS MOISTURE
CONTINUES TO WRAP AROUND THE BACK OF THE TROUGH. EXPECT SHOWERS TO
DIMINISH FOR THESE AREAS IN THE LATE MORNING TOMORROW. HAVE
UPDATED THE FORECAST FOR SHOWERS THIS EVENING INTO EARLY THURSDAY
MORNING, MAINLY TO INCREASE THE ISOLATED SHOWERS EAST OF THE
CASCADES TONIGHT INTO EARLY TOMORROW MORNING.
OTHERWISE THE MAIN CONCERN IS HOW MUCH AND HOW QUICKLY AREAS WEST
OF THE CASCADES WILL SEE CLEARING AND HOW MUCH FROST MAY DEVELOP
IN SOME OF THE WEST SIDE VALLEYS. THE 00Z NAM IS SHOWING SLIGHTLY
MORE MOISTURE THAN THE EARLIER RUN FOR TONIGHT. THE RAP MODEL ALSO
CONTINUES TO INDICATE MOISTURE AND SOME CLOUDS ACROSS WEST SIDE
AREAS TONIGHT. BOTH THE NAM AND RAP SUPPORT A POTENTIAL FOR BROKEN
TO SCATTERED CLOUDS WEST OF THE CASCADES TONIGHT WITH CLEARING
MORE LIKELY IN THE EARLY MORNING HOURS VERSUS THE LATE NIGHT
HOURS. HOWEVER AS MODELS DO SHOW A POTENTIAL FOR CLEARING DURING
THE EARLY MORNING ALONG WITH COLD AIR ALOFT MOVING OVERHEAD, HAVE
KEPT THE LOW TEMPERATURE FORECAST UNCHANGED FOR THURSDAY MORNING
AND HAVE KEPT THE FROST ADVISORIES IN PLACE FOR JACKSON AND
JOSEPHINE COUNTIES IN OREGON AND FOR THE SCOTT AND SHASTA VALLEYS
IN SISKIYOU COUNTY IN CALIFORNIA.
&&
.AVIATION...A VIGOROUS UPPER LEVEL LOW WILL MOVE SOUTHEASTWARD ACROSS THE
FORECAST AREA FROM THE NORTHWEST THIS EVENING BRINGING SHOWERS TO
SOME OF THE AREA, MOST INTENSE OVER NORTHEASTERN SECTIONS OF THE
AREA IN DOUGLAS, KLAMATH, AND LAKE COUNTIES. PARTIAL CLEARING
OVERNIGHT THROUGH THURSDAY MORNING WILL YIELD A VARIETY OF
CONDITIONS BY MORNING, PRIMARILY RESULTING IN IFR TO MVFR CONDITIONS
IN MOST OF THE WEST SIDE AND COASTAL VALLEYS, AND PARTIAL TERRAIN
OBSCURATIONS FROM THE CASCADES WESTWARD. EXPECT MOST AREAS TO CLEAR
BY LATE MORNING. BTL
&&
.PREV DISCUSSION... /ISSUED 625 PM PDT WED OCT 2 2013/
DISCUSSION...THE REGION TRANSITIONS FROM THE WET AND COLD PATTERN
TO A COLD AND DRY PATTERN TOMORROW. A WEAK COLD FRONT MOVES THROUGH
THE REGION THIS EVENING...BRINGING LIGHT PRECIP FROM MOSTLY THE
UMPQUA DIVIDE NORTHWARD. THIS SHOULD BE THROUGH THE REGION LATE THIS
EVENING WITH CLEARING SOUTH OF THE UMPQUA DIVIDE LATE EVENING.
WITH THE TIMING BEING CRITICAL TO THE LOW TEMPERATURES WITH 850 MB
TEMPS NEAR ZERO COMPARED TO THIS MORNINGS 4 C AT 850...AM
EXPECTING SKIES TO CLEAR EARLY ENOUGH TO COMBINE WITH THE COOLER
TEMPS ALOFT TO BRING WIDESPREAD FROST TO THE WEST SIDE VALLEYS
SOUTH OF THE UMPQUA DIVIDE. LOW CLOUDS SHOULD STAY NORTH OF THE
DIVIDE TO KEEP TEMPS WARMER THERE. THE EAST SIDE WILL SEE
WIDESPREAD FREEZE WITH AREAS IN THE LOWER 20S...BUT WIDESPREAD
DEEP FREEZE HAS ALREADY KILLED ANY SENSITIVE VEGETATION IN THAT
AREA ALREADY. BY TOMORROW NIGHT THE UPPER LEVEL RIDGE HAS BUILT
INTO THE REGION WITH OFFSHORE FLOW ALL THE WAY ACROSS THE EAST
SIDE. THIS WILL CLEAR THINGS OUT EARLY...BUT 850 TEMPS INCREASE TO
AROUND 6C AND WITH THE WARMER TEMPS ALOFT AM EXPECTING A REPEAT OF
TONIGHT`S LOWS. THE OFF SHORE FLOW CONTINUES ANOTHER DAY WITH 850
TEMPS INCREASING TO THE 12-14C RANGE BRINGING WARM AND DRY
CONDITIONS TO THE RIDGE TOPS AND A VERY STRONG INVERSION TO THE
VALLEY FLOORS. WITH OFFSHORE FLOW REMAINING ON THE COAST TEMPS IN
THE BROOKINGS AREA MAY BE WARMER THAN THE INLAND VALLEYS ON FRIDAY.
EXTENDED TERM...SUNDAY THROUGH WEDNESDAY NIGHT.
THERE CONTINUES TO BE LOW CONFIDENCE IN THE EXTENDED TERM. THE GFS
AND ECMWF ENSEMBLES BOTH HAVE A WIDE RANGE OF SOLUTIONS...BUT THERE
IS A DISCERNIBLE AGREEMENT IN THE GENERAL PATTERN OF THE OPERATION
RUNS. THE ECMWF STILL REMAINS THE MOST CONSISTENT SOLUTION...SO
WHILE THE EXTENDED PERIOD IS BASED ON A GENERAL BLEND OF THE
SYNOPTIC MODELS...HAVE TILTED THE FORECAST TOWARDS THE LATEST EC
SOLUTION.
THE EXTENDED PERIOD BEGINS WITH A WEAK FRONT MOVING ONSHORE SUNDAY.
WHILE THE GFS HAS PRODUCED A MORE VIGOROUS LOW TO THE NORTH...BOTH
THE EC AND GFS ARE PRODUCING VERY SIMILAR PRECIPITATION FIELDS.
PRECIPITATION WILL BE MOSTLY CONCENTRATED ALONG THE COAST AND INTO
THE COASTAL RANGE...AS WELL AS THE UMPQUA BASIN AND THE WESTERN
SLOPES OF THE CASCADES NORTH OF MT MCLOUGHLIN. THE INLAND VALLEYS OF
SOUTHWESTERN OREGON AND THE EAST SIDE WILL REMAIN DRY...AS MOST OF
THE MOISTURE AND ENERGY OF THE SYSTEM IS EXPECTED TO REMAIN
NORTH...AND DOWNSLOPING WILL PREVENT PRECIPITATION FROM MAKING
SIGNIFICANT INROADS INTO THOSE AREAS. A SECONDARY AND MUCH WEAKER
WAVE IS POSSIBLE SUNDAY NIGHT INTO MONDAY MORNING...BUT WILL DO
LITTLE MORE THAN REINFORCE THE SHOWER ACTIVITY ALREADY ONGOING.
ONCE THE TROUGH LEAVES THE AREA MONDAY...A LARGE RIDGE WILL LIKELY
DEVELOP OVER THE EASTERN PACIFIC...WHILE DOWNWIND A TROUGH IS
EXPECTED TO DIG IN ALONG THE ROCKY MOUNTAINS. THIS WILL PLACE THE
REGION IN NORTHWESTERLY TO WESTERLY FLOW ALOFT. THIS PATTERN HAS A
TENDENCY TO KEEP THE REGION MOSTLY DRY...AND KEEP TEMPERATURES ON
THE COOLER SIDE OF NORMAL. HAVE KEPT THE EXTENDED PERIOD FORECAST IN
LINE WITH THIS THINKING THROUGH THE REMAINDER OF THE TERM.
HOWEVER...THERE IS A POSSIBILITY OF A WAVE OR TWO WITHIN THE FLOW
ALOFT TO PASS OVER THE REGION...BUT WITH VERY LITTLE CERTAINTY IN
ANY SUCH FEATURE...HAVE LEFT ANY MENTION OF POPS OUT OF THE FORECAST
PACKAGE.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY FROM 2 AM TO 8 AM PDT THURSDAY FOR ORZ024-026.
FROST ADVISORY FROM 2 AM TO 8 AM PDT FRIDAY FOR ORZ024-026-028.
CA...FROST ADVISORY FROM 2 AM TO 8 AM PDT THURSDAY FOR CAZ080-081.
FROST ADVISORY FROM 2 AM TO 8 AM PDT FRIDAY FOR CAZ080-081-083.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM TO 11 PM PDT THURSDAY
FOR PZZ356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 PM TO 11 PM PDT
THURSDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM THURSDAY TO 5 AM PDT
SATURDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PDT THIS
EVENING FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 PM THURSDAY TO 5
AM PDT SATURDAY FOR PZZ376.
$$
CC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
801 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT DRAPED JUST TO THE NORTH OF THE STATE WILL STAY IN
PLACE OVER THE NEXT FEW DAYS. FAST WESTERLY FLOW ALOFT WILL ALLOW
A SERIES OF WEAK WAVES TO ROLL ACROSS THE AREA THIS WEEKEND. A
STRONG COLD FRONT WILL MOVE THROUGH LATE SUNDAY OR EARLY MONDAY.
TROPICAL MOISTURE FROM TROPICAL STORM KAREN MAY BE DRAWN INTO THE
STATE FROM THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
CLOUDS ASSOCIATED WITH A DYING SHORTWAVE ARE BREAKING UP AS THEY
TRY TO TRAVEL ACROSS THE CENTRAL MOUNTAINS. HOWEVER...ANOTHER WAVE
IS MOVING DOWN FROM MICHIGAN...AND SHOULD PASS THROUGH LATE THIS
MORNING AND THROUGH THE AFTERNOON. THIS SHORTWAVE WILL ENHANCE
THE LIFT OF ANOMALOUSLY WARM AND MOIST AIR OVER THE REGION FOR
EARLY OCTOBER. EXPECT SCT SHRA AND ISOLD TSRA TO FORM THROUGH THE MORNING
HOURS IN WRN PA AND ROLL INTO THE AREA. MOST OF THE SHOWERS
SHOULD BE TO THE NW OF AOO/UNV/IPT...BUT ISOLD SHRA ARE POSS IN
THE SE. WILL KEEP A 20 POP THERE FOR THE MORNING...BUT RAISE THEM
TO SCT POPS IN THE AFTERNOON. SHOWERS WILL BE MOVING ALONG
STEADILY WITH GENERAL 20-30KT WEST WIND FOR THE ENTIRE ATMOS BELOW
300MB. PWATS IN THE 1.5 INCH RANGE WILL ALLOW FOR A FEW INTENSE
BUT VERY BRIEF DOWNPOURS. MAXES WILL BE LIMITED BY THE CLOUD COVER
OVER THE NORTH...BUT BIG BREAKS IN THE SRN HALF OF THE AREA WILL
HELP TEMPS TO GET ABOVE 80F OVER ALMOST HALF THE AREA.
STILL...THESE ARE WAYYYY ABOVE NORMS FOR THE DATE.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM SATURDAY/...
SHORT WAVE SHOULD BE PUSHING TO THE EAST AND TAKING THE
SHOWERS/THUNDER WITH IT AS LOW SUN ANGLE/SHORTER DAYS LIMIT THE
INSTABILITY. WARM FRONT REMAINS GENERALLY TO THE NORTH...BUT SKY
SHOULD BE CLOUDY IN THE NE AND PARTLY CLOUDY ELSEWHERE TONIGHT.
ONCE AGAIN...DEWPOINTS HIGH FOR THE DATE AND TEMPS WILL STAY MUCH
ABOVE NORMALS WITH MINS NEAR 55F IN THE N AND NEAR 60F IN THE S.
RIDGE ALOFT PUMPS UP SLIGHTLY DURING THE DAY ON SATURDAY. BUT THE
FRONT TO OUR NORTH MAY PUSH SOUTHWARD A HUNDRED MILES OR
SO...KEEPING A LOW THREAT OF RAIN IN THE NORTH LATER TONIGHT AND
INTO SAT NIGHT. DIURNAL CONVECTION COULD CREATE SHOWERS OVER THE
WRN HILLS SAT AFTN...BUT THESE SHOULD BREAK UP AS THEY TRY TO MOVE
ACROSS THE CWA. THE HIGHER CLOUD COVER IN THE N/NE SHOULD KEEP
MAXES TO THE M70S...BUT ALL OTHER LOCATIONS SHOULD ADD A DEG OR
TWO TO FRI/S MAXES WITH MORE SUN/LESS CLOUDS ON THE WHOLE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
DIGGING TROUGH EXITS THE ROCKY MTNS ON FRI AND SLOWLY HEADS TOWARD
THE GREAT LAKES THROUGH THE WEEKEND...PUSHING A COLD FRONT
GRADUALLY TOWARD PENNSYLVANIA.
THIS WEEKEND WILL FEATURE A WEAK W-E ORIENTED WARM FRONT SNAKED
ACROSS THE REGION THAT WILL LIFT INTO NY STATE...ALLOWING A WARM
AND FAIRLY HUMID AIRMASS TO SETTLE IN OVER THE FCST AREA. MODELS
CONTINUE TO SPLASH AROUND SOME LIGHT QPF WHICH SEEMS MAINLY
DIURNALLY FAVORED...BUT ODDS ARE THAT FOR MAJORITY IF CENTRAL PA
IT SHOULD BE A MAINLY NICE AND DRY WEEKEND. BEST CHANCES FOR LIGHT
SHOWERS WILL BE IN THE NORTH AND WEST. HIGH TEMPS WILL BE IN THE
MID 70S TO LOWER 80S...A SOLID 15F ABOVE NORMAL.
THEN FOCUS TURNS TO APPROACHING COLD FRONT. GUIDANCE HAS TRENDED
BACK TO NOTABLE TIMING DIFFERENCES...WITH THE GFS MORE
PROGRESSIVE IN BRINGING FRONT ACROSS SUN NIGHT...WHILE THE ECMWF
HOLDS IT BACK UNTIL MONDAY AND THEN SLOWS THE FRONTAL BOUNDARY
ORIENTED SW-NE OVER SOUTHEAST PA. SREF AND NAM ALSO SEEM TO FAVOR
THE QUICKER FROPA...SO SHADED HIGHEST POPS TOWARD SUN NIGHT/EARLY
MON...ESP IN THE WEST.
EARLY NEXT WEEK THE ISSUE BECOMES HOW TROPICAL MOISTURE FROM
EVENTUAL REMNANTS OF KAREN /MOVING TOWARD GULF COAST/ WILL
ULTIMATELY INTERACT WITH THE LINGERING FRONTAL BOUNDARY OVER MID
ATLANTIC STATES. BEST FORECAST REMAINS THAT KAREN WILL TRACK UP
ALONG OR EVEN MORE LIKELY EAST OF THE COLD FRONT THROUGH THE
CAROLINAS AND THEN OFF THE MID ATLC COAST...NOT BEING A THREAT TO
PA. THE ECMWF IS A SIG OUTLIER...TAKING THE STORM FURTHER WEST AND
ABSORBING IT INTO ITS SLOWER MOVING FRONT...BRINGING SIG RAINS UP
INTO WESTERN/CENTRAL PA FOR MID NEXT WEEK. I DID SHADE POPS IN
EASTERN COUNTIES A LITTLE HIGHER...HOLDING ONTO POPS FURTHER INTO
TUE ATTM.
QUIET AND SLIGHTLY COOLER WEATHER WILL ULTIMATELY RETURN FOR
MIDWEEK AFTER THE FRONT AND TROPICAL MOISTURE MOVES
THROUGH...DROPPING TEMPS BACK TOWARD YET STILL SLIGHTLY ABOVE
NORMAL. BUT WITH THE LONGER RANGE MODELS ADVERTISING A RESURGENCE
IN THE EASTERN RIDGE...WARMER AIR SHOULD MAKE A RETURN FOR THE
LATTER HALF OF NEXT WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
WARM FRONT AND BULK OF SHRA HAVE LIFTED NORTH OF PA EARLY THIS
MORNING. IN IT/S WAKE...LOW LVL MOISTURE ASCENDING THE NW MTNS IS
PRODUCING LOW CIGS AT BFD. MDL SOUNDINGS SUGGEST IT WILL TAKE
UNTIL ARND 15Z TO MIX OUT THESE LOW CIGS. ACROSS SOUTHEAST
PA...CLEAR SKIES ALL NIGHT ALLOWED RADIATION FOG TO FORM AT
LNS...WHERE THE 11Z VIS IS 1SM. LATEST HRRR AND NAMPARA SUGGEST
THIS FOG BURNS OFF BTWN 13Z-14Z.
WIDESPREAD VFR CONDS APPEAR NEARLY CERTAIN OVER MOST OF CENTRAL PA
BY MIDDAY...WITH THE POSSIBLE EXCEPTION OF BFD. A FEW LATE DAY
SHRA/TSRA MAY DEVELOP ACROSS NORTHERN PA IN VICINITY OF QUASI-
STATIONARY FRONT ACROSS UPSTATE NY. THUS...CAN/T RULE OUT A BRIEF
LATE DAY VSBY REDUCTION AT THE NORTHERN PA AIRFIELDS.
MCLEAR SKIES...A CALM WIND AND ABUNDANT LOW LVL MOISTURE SHOULD
LEAD TO AREAS OF FOG TONIGHT. MANY LOCATIONS WILL LIKELY BECOME
IFR BY DAWN ACROSS NORTHERN PA BASED ON LATEST SREF OUTPUT.
OUTLOOK...
SAT...AM FOG POSSIBLE...MAINLY NORTH. ISOLD PM TSRA IMPACTS POSS NORTH.
SUN...AM FOG POSS EAST. ISOLD PM TSRA IMPACTS POSS W MTNS.
MON...SHRA/LOW CIGS POSSIBLE...ESP EARLY.
TUE...SLIGHT CHC OF SHRA/LOW CIGS SOUTHEAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO/GARTNER
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
726 AM EDT FRI OCT 4 2013
.SYNOPSIS...
A WARM FRONT DRAPED JUST TO THE NORTH OF THE STATE WILL STAY IN
PLACE OVER THE NEXT FEW DAYS. FAST WESTERLY FLOW ALOFT WILL ALLOW
A SERIES OF WEAK WAVES TO ROLL ACROSS THE AREA THIS WEEKEND. A
STRONG COLD FRONT WILL MOVE THROUGH LATE SUNDAY OR EARLY MONDAY.
TROPICAL MOISTURE FROM TROPICAL STORM KAREN MAY BE DRAWN INTO THE
STATE FROM THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
CLOUDS ASSOCIATED WITH A DYING SHORT WAVE ARE BREAKING UP AS THEY
TRY TO TRAVEL ACROSS THE CENTRAL MOUNTAINS. HOWEVER...ANOTHER WAVE
IS MOVING DOWN FROM MICHIGAN...AND SHOULD PASS THROUGH LATE THIS
MORNING AND THOUGH THE AFTERNOON. THIS SHORT WAVE WILL ENHANCE
THE LIFT OF ANOMALOUSLY WARM AND MOIST AIR FOR EARLY OCTOBER.
EXPECT SCT SHRA AND ISOLD TSRA TO FORM THIS MORNING IN WRN PA AND
ROLL INTO THE AREA. MOST OF THE SHOWERS SHOULD BE TO THE NW OF
AOO/UNV/IPT...BUT ISLOD SHRA ARE POSS IN THE SE. WILL KEEP A 20
POP THERE FOR THE MORNING...BUT RAISE THEM TO SCT POPS IN THE
AFTERNOON. SHOWERS WILL BE MOVING ALONG STEADILY WITH GENERAL
20-30KT WEST WIND FOR THE ENTIRE ATMOS BELOW 300MB. PWATS IN THE
1.5 INCH RANGE WILL ALLOW FOR A FEW INTENSE BUT VERY BRIEF
DOWNPOURS. MAXES WILL BE LIMITED BY THE CLOUD COVER OVER THE
NORTH...BUT BIG BREAKS IN THE SRN HALF OF THE AREA WILL HELP TEMPS
TO GET ABOVE 80F OVER ALMOST HALF THE AREA. STILL...THESE ARE
WAYYYY ABOVE NORMS FOR THE DATE.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM SATURDAY/...
SHORT WAVE SHOULD BE PUSHING TO THE EAST AND TAKING THE
SHOWERS/THUNDER WITH IT AS LOW SUN ANGLE/SHORTER DAYS LIMIT THE
INSTABILITY. WARM FRONT REMAINS GENERALLY TO THE NORTH...BUT SKY
SHOULD BE CLOUDY IN THE NE AND PARTLY CLOUDY ELSEWHERE TONIGHT.
ONCE AGAIN...DEWPOINTS HIGH FOR THE DATE AND TEMPS WILL STAY MUCH
ABOVE NORMALS WITH MINS NEAR 55F IN THE N AND NEAR 60F IN THE S.
RIDGE ALOFT PUMPS UP SLIGHTLY DURING THE DAY ON SATURDAY. BUT THE
FRONT TO OUR NORTH MAY PUSH SOUTHWARD A HUNDRED MILES OR
SO...KEEPING A LOW THREAT OF RAIN IN THE NORTH LATER TONIGHT AND
INTO SAT NIGHT. DIURNAL CONVECTION COULD CREATE SHOWERS OVER THE
WRN HILLS SAT AFTN...BUT THESE SHOULD BREAK UP AS THEY TRY TO MOVE
ACROSS THE CWA. THE HIGHER CLOUD COVER IN THE N/NE SHOULD KEEP
MAXES TO THE M70S...BUT ALL OTHER LOCATIONS SHOULD ADD A DEG OR
TWO TO FRI/S MAXES WITH MORE SUN/LESS CLOUDS ON THE WHOLE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
DIGGING TROUGH EXITS THE ROCKY MTNS ON FRI AND SLOWLY HEADS TOWARD
THE GREAT LAKES THROUGH THE WEEKEND...PUSHING A COLD FRONT
GRADUALLY TOWARD PENNSYLVANIA.
THIS WEEKEND WILL FEATURE A WEAK W-E ORIENTED WARM FRONT SNAKED
ACROSS THE REGION THAT WILL LIFT INTO NY STATE...ALLOWING A WARM
AND FAIRLY HUMID AIRMASS TO SETTLE IN OVER THE FCST AREA. MODELS
CONTINUE TO SPLASH AROUND SOME LIGHT QPF WHICH SEEMS MAINLY
DIURNALLY FAVORED...BUT ODDS ARE THAT FOR MAJORITY IF CENTRAL PA
IT SHOULD BE A MAINLY NICE AND DRY WEEKEND. BEST CHANCES FOR LIGHT
SHOWERS WILL BE IN THE NORTH AND WEST. HIGH TEMPS WILL BE IN THE
MID 70S TO LOWER 80S...A SOLID 15F ABOVE NORMAL.
THEN FOCUS TURNS TO APPROACHING COLD FRONT. GUIDANCE HAS TRENDED
BACK TO NOTABLE TIMING DIFFERENCES...WITH THE GFS MORE
PROGRESSIVE IN BRINGING FRONT ACROSS SUN NIGHT...WHILE THE ECMWF
HOLDS IT BACK UNTIL MONDAY AND THEN SLOWS THE FRONTAL BOUNDARY
ORIENTED SW-NE OVER SOUTHEAST PA. SREF AND NAM ALSO SEEM TO FAVOR
THE QUICKER FROPA...SO SHADED HIGHEST POPS TOWARD SUN NIGHT/EARLY
MON...ESP IN THE WEST.
EARLY NEXT WEEK THE ISSUE BECOMES HOW TROPICAL MOISTURE FROM
EVENTUAL REMNANTS OF KAREN /MOVING TOWARD GULF COAST/ WILL
ULTIMATELY INTERACT WITH THE LINGERING FRONTAL BOUNDARY OVER MID
ATLANTIC STATES. BEST FORECAST REMAINS THAT KAREN WILL TRACK UP
ALONG OR EVEN MORE LIKELY EAST OF THE COLD FRONT THROUGH THE
CAROLINAS AND THEN OFF THE MID ATLC COAST...NOT BEING A THREAT TO
PA. THE ECMWF IS A SIG OUTLIER...TAKING THE STORM FURTHER WEST AND
ABSORBING IT INTO ITS SLOWER MOVING FRONT...BRINGING SIG RAINS UP
INTO WESTERN/CENTRAL PA FOR MID NEXT WEEK. I DID SHADE POPS IN
EASTERN COUNTIES A LITTLE HIGHER...HOLDING ONTO POPS FURTHER INTO
TUE ATTM.
QUIET AND SLIGHTLY COOLER WEATHER WILL ULTIMATELY RETURN FOR
MIDWEEK AFTER THE FRONT AND TROPICAL MOISTURE MOVES
THROUGH...DROPPING TEMPS BACK TOWARD YET STILL SLIGHTLY ABOVE
NORMAL. BUT WITH THE LONGER RANGE MODELS ADVERTISING A RESURGENCE
IN THE EASTERN RIDGE...WARMER AIR SHOULD MAKE A RETURN FOR THE
LATTER HALF OF NEXT WEEK.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
WARM FRONT AND BULK OF SHRA HAVE LIFTED NORTH OF PA EARLY THIS
MORNING. IN IT/S WAKE...LOW LVL MOISTURE ASCENDING THE NW MTNS IS
PRODUCING LOW CIGS AT BFD. MDL SOUNDINGS SUGGEST IT WILL TAKE
UNTIL ARND 15Z TO MIX OUT THESE LOW CIGS. ACROSS SOUTHEAST
PA...CLEAR SKIES ALL NIGHT ALLOWED RADIATION FOG TO FORM AT
LNS...WHERE THE 11Z VIS IS 1SM. LATEST HRRR AND NAMPARA SUGGEST
THIS FOG BURNS OFF BTWN 13Z-14Z.
WIDESPREAD VFR CONDS APPEAR NEARLY CERTAIN OVER MOST OF CENTRAL PA
BY MIDDAY...WITH THE POSSIBLE EXCEPTION OF BFD. A FEW LATE DAY
SHRA/TSRA MAY DEVELOP ACROSS NORTHERN PA IN VICINITY OF QUASI-
STATIONARY FRONT ACROSS UPSTATE NY. THUS...CAN/T RULE OUT A BRIEF
LATE DAY VSBY REDUCTION AT THE NORTHERN PA AIRFIELDS.
MCLEAR SKIES...A CALM WIND AND ABUNDANT LOW LVL MOISTURE SHOULD
LEAD TO AREAS OF FOG TONIGHT. MANY LOCATIONS WILL LIKELY BECOME
IFR BY DAWN ACROSS NORTHERN PA BASED ON LATEST SREF OUTPUT.
OUTLOOK...
SAT...AM FOG POSSIBLE...MAINLY NORTH. ISOLD PM TSRA IMPACTS POSS NORTH.
SUN...AM FOG POSS EAST. ISOLD PM TSRA IMPACTS POSS W MTNS.
MON...SHRA/LOW CIGS POSSIBLE...ESP EARLY.
TUE...SLIGHT CHC OF SHRA/LOW CIGS SOUTHEAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
718 AM EDT THU OCT 3 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S. KEEPING THE
REGION UNSEASONABLY WARM AND EVEN A BIT HUMID AT LEAST THROUGH
THE WEEKEND. A COLD FRONT WILL APPROACH THE REGION LATER IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SATELLITE SHOWS SOME MAINLY THIN HIGH CLOUDS STREAMING INTO THE
REGION. OTHERWISE IT`S ANOTHER FAIR EARLY AUTUMN NIGHT. A SLIGHT
DEWPOINT DISCONTINUITY FROM NW PA SE INTO THE MID SUSQ VALLEY
SUGGEST THE GHOST OF THE OLD FRONT THAT WEAKENED AS IT MOVED INTO
PA A COUPLE OF DAYS AGO IS STILL HANGING AROUND...AND IT LOOKS LIKE
IT COULD PROVIDE JUST ENOUGH FOCUS TO TRIGGER A FEW SHOWERS OR
THUNDERSTORMS LATER TODAY. SREF AND GFS WANT TO COOK UP SOME WEAK
CAPE AS PWATS RISE TO 1-3 SD ABOVE NORMAL. THE BEST CHANCE OF
SHOWERS TODAY SHOULD BE OVER THE NW...CLOSEST TO THE BEST FRONTAL
FORCING AND PW SURGE.
IT WILL BE YET ANOTHER WARM DAY WITH HIGHS FROM THE MID 70S OVER
THE NORTH...TO THE LOW AND MID 80S ALONG THE MD BORDER.
THE FRONT IS MADE TO SNAKE OUT OF THE OHIO VALLEY AN UP ALONG THE
NY/PA BORDER INTO THE OVERNIGHT. THE SFC BASED LI`S SHOW THIS
NICELY AND THIS SHOULD BE ONCE AGAIN THE AREA MOST FAVORED FOR
SHOWERS/THUNDER DURING THE SECOND PERIOD.
WITH MORE CLOUDS...THE OVERNIGHT WILL STAY QUITE WARM WITH LOWS IN
THE 50S TO LOWER 60S.
&&
.SHORT TERM /FRIDAY/...
GUIDANCE SHOWS THAT THE WARM FRONT SHOULD BE MAINLY NORTH OF PA
FRIDAY IMPLYING A WARM AND EVEN MUGGY DAY. THE OPERATIONAL MODELS
SHOW A SMATTERING OF LIGHT QPF...AND MOS POPS ARE FAIRLY
HIGH...ESPECIALLY OVER THE NORTH. WITH THE FRONTAL FORCING REMOVED
FROM THE FCST AREA...IT SEEMS SHORT RANGE GUIDANCE MAY BE LATCHING
ONTO SOME SORT OF UPSTREAM MCS ACTIVITY TRACKING ACROSS THE AREA.
THE GEFS/SREF SHOW THIS POTENTIAL BY ALSO GENERATING SOME WEAK
CAPE OVER ABOUT THE NORTHERN HALF OF PA. HAVE TAPERED POPS FROM
VERY LOW CHANCES OVER THE SOUTH TO LOW LIKELY NUMBERS ALONG THE NY
BORDER...BUT KEEPING ACTUAL PRECIP AMOUNTS ON THE LIGHT SIDE
BARRING HINTS OF STRONGER AND WELL ORGANIZED CONVECTION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE WEEKEND SHOULD FEATURE A COLD FRONT WELL TO OUR WEST...A WARM
FRONT OVER NY AND A WARM FAIRLY HUMID AIRMASS IN PLACE OVER THE
FCST AREA. MODELS ONCE AGAIN SPLASH AROUND SOME LIGHT QPF WHICH
SEEMS MAINLY DIURNALLY FAVORED...BUT THINKING IS IT SHOULD BE A
MAINLY NICE-DRY WEEKEND FOR MOST OF THE TIME OVER MOST OF THE
AREA.
THE DIFFERENCES IN GUIDANCE ARE CENTERED ON COLD FRONTAL TIMING
AND HANDLING OF WHATEVER TROPICAL MOISTURE ENDS UP MOVING INTO THE
GULF STATES. THE GEFS/GFS SUGGEST POTENTIAL STORM KAREN MAKES A
LANDFALL OVER THE FL PANHANDLE BEFORE TRACKING UP ALONG OR EAST
OF A FASTER MOVING COLD FRONT THROUGH THE CAROLINAS AND THEN OFF
THE MID ALTL COAST...NOT BEING A THREAT TO PA. THE ECMWF TAKES
THE STORM TO LOUISIANA BEFORE ABSORBING IT INTO A SLOWER MOVING
FRONT...BRINGING SIG RAINS UP INTO WESTERN/CENTRAL PA.
AT THIS RANGE WITH SUCH GREAT UNCERTAINTY...I DIDN`T MAKE ANY SIG
CHANGES TO THE END OF THE EXTENDED...BASICALLY NOT DRYING THINGS
OUT UNTIL TUESDAY...RATHER THAN LATE MONDAY AND MONDAY NIGHT AS
THE FASTER GEFS/GFS WOULD HAVE.
QUIET AND SLIGHTLY COOLER WEATHER WILL ULTIMATELY RETURN FOR
MIDWEEK AFTER THE FRONT MOVES THROUGH. BUT WITH THE LONGER RANGE
MODELS ADVERTISING A RESURGENCE IN THE EASTERN RIDGE...WARMER AIR
SHOULD MAKE A RETURN FOR THE LATTER HALF OF NEXT WEEK...WITH THE
ECMWF ADVERTISING 500MB HEIGHTS APPROACHING 590DM BY FRIDAY!
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
EARLY AM MODIS 11-3.7UM IMAGERY SHOWS DENSE VALLEY FOG OVER PORTIONS
OF CENTRAL PA. BASED ON HRRR AND NAMPARA...FOG SHOULD MIX OUT BY
ARND 14Z...LEAVING WIDESPREAD VFR FLYING CONDS FOR THE REST OF THE
DAY. FOCUS WILL THEN SHIFT TOWARD THE POSSIBILITY OF A LATE DAY
SHRA/TSRA ACROSS THE W MTNS IN ASSOCIATION WITH OLD BOUNDARY
LIFTING NORTH AS A WARM FRONT. A MOIST SW FLOW ASCENDING THE NW
MTNS WILL LIKELY PRODUCE LOW CIGS/FOG AT BFD LATE TONIGHT.
OUTLOOK...
FRI...AM LOW CIGS/FOG POSS BFD. ISOLD PM TSRA IMPACTS POSS.
SAT...AM FOG POSSIBLE.
SUN...AM FOG POSSIBLE EAST. PM TSRA IMPACTS POSS W MTNS.
MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
200 PM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL LINGER OVER THE REGION THROUGH SATURDAY. A
COLD FRONT...POSSIBLY ENHANCED WITH DEEP LAYER MOISTURE FROM TROPICAL
STORM KAREN...WILL APPROACH FROM THE WEST ON SUNDAY AND BRING
UNSETTLED AND RAINY WEATHER TO THE AREA SUNDAY NIGHT THROUGH MONDAY.
HIGH PRESSURE WILL THEN RETURN IN THE FRONTS WAKE ON TUESDAY AND
STRENGTHEN THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM...FORECAST HAS BEEN UPDATED PRIMARILY FOR AVIATION
PURPOSES. HOWEVER...ADDITIONAL ADJUSTMENTS TO SKY AND TEMPS HAVE
BEEN MADE TO ALIGN WITH OBSERVATIONS.
AS OF 1145 AM...CLOUD COVER ACROSS THE FOOTHILLS AND PIEDMONT HAS
CONTINUED TO DECREASE OVER THE PAST HOUR. UPSTREAM CLOUD COVER HAS
THINNED AS WELL. I WILL UPDATE THE FORECAST TO DECREASE CLOUD COVER
EAST OF THE MTNS THROUGH THE EARLY AFTERNOON. IN ADDITION...I WILL
WARM THIS AFTERNOON HIGH TEMPERATURE A CLICK OR TWO. CAMS INDICATE
THAT A FEW SHRAS MAY EXIST ACROSS THE NC MTNS THROUGH THE AFTERNOON
HOURS. COVERAGE APPEAR GREATEST DURING THE MID TO LATE
AFTERNOON...RESPONDING TO THE PASSAGE OF A WEAK S/W.
AS OF 11 AM...I HAVE ISSUED A QUICK UPDATE TO ADJUST SKY AND TEMP IN
LINE WITH LATEST OBSERVATIONS. KGSP RADAR CONTINUES TO INDICATE WEAK
RETURNS ACROSS THE NC MTNS...I WILL MAINTAIN SCHC POPS.
AS OF 700 AM EDT...KGSP RADAR CONTINUES TO SHOW SPORADIC 20 TO 25
DBZ ECHOES ALONG MAINLY THE SPINE OF THE SOUTHERN APPALACHIANS AT
DAYBREAK. ADDITIONAL WEAK FORCING FROM UPPER WAVES PASSING ALONG THE
NC/TN BORDER MAY DRIVE VERY LIGHT ISOLD RAIN SHOWERS...BUT ANY
PRECIP SHOULD BE CONFINED TO MAINLY THE HIGHER ELEVATIONS AND THE
FAR WRN MTNS. THE CURRENTLY PASSING SHORTWAVE WILL LIFT NWD THROUGH
THE CENTRAL APPALACHIANS TODAY...FOLLOWED BY A TRAILING SHORTWAVE
INTO THE AFTN HOURS. MAINLY MID AND HIGH LEVEL CLOUDS WILL CONTINUE
E OF THESE WAVES FOR A GOOD PART OF THE DAY. THE NAM CONTINUES TO
SHOW MORE ROBUST QPF OVER THE MTNS TODAY...ATTRIBUTED MAINLY TO LESS
CAPPING IN THE PROFILES. THIS APPEARS TO BE OVERDONE IN COMPARISON
TO THE OTHER NUMERICAL MODELS...SO WILL LEAN STRONGLY TOWARD THE
DRIER GFS AND RAP SOLUTIONS...WITH ONLY ISOLATED SHOWERS ALONG THE
MTN CHAIN AND DRY CONDITIONS EAST. DESPITE THE ABUNDANT MID/HIGH
CLOUDS...LOW LEVEL THICKNESSES WILL REACH OR SURPASS YESTERDAY
VALUES...WITH COMPARABLE MAXES OR TEMPS POSSIBLY A DEGREE WARMER IN
ERN SECTIONS.
FLAT RIDGING WILL THEN REDEVELOP BEHIND THE DEPARTING WAVES TONIGHT.
THE OPERATIONAL MOS IS QUITE COOL FOR MIN TEMPS...BUT WILL LEAN
HEAVILY TOWARD THE WARMER BIAS CORRECTED VALUES AS THE AIRMASS
CONTINUES TO MODIFY. ANOTHER ROUND OF EARLY MORNING MOUNTAIN VALLEY
CAN BE EXPECTED OVERNIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 1 PM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 00Z ON
SATURDAY WITH THE UPPER RIDGE IN PLACE OVER THE SE CONUS AND A
DEEPENING UPPER TROUGH DIVING DOWN OVER THE NORTHERN AND CENTRAL
PLAINS. AT THE SAME TIME...WHAT IS CURRENTLY TROPICAL STORM KAREN IS
MOVING NORTHWARD OVER THE NORTH CENTRAL GULF OF MEXICO. UPPER RIDING
IS EXPECTED TO REMAIN OVER THE FCST AREA THRU THE END OF THE PERIOD
12Z SUNDAY.
ON SATURDAY...WEAK SFC HIGH PRESSURE WILL PERSIST OVER THE REGION AS A
STRONG SFC CYCLONE EJECTS OUT OF THE PLAINS AND MAKES ITS WAY
TOWARDS THE GREAT LAKES. TS KAREN WILL ALSO BE MAKING HER WAY
NORTHWARD TOWARDS THE NORTHERN GULF COAST AND IS CURRENTLY EXPECTED
TO MAKE LANDFALL SOMETIME SUNDAY MORNING. AS THE SYSTEM
APPROACHES...DEEPER LAYER MOISTURE WILL SURGE NORTHWARD FROM THE GULF
COAST AND ENCROACH UPON THE CWFA BY THE END OF THE PERIOD AT 12Z
SUNDAY. NO SIGNIFICANT CHANGES WERE NEEDED FOR THE SENSIBLE FCST FOR
THE PERIOD WITH ONLY A SLIGHT CHANCE POP FOR SAT AFTERNOON/EVENING
OVER THE HIGHER TERRAIN AND PORTIONS OF THE FOOTHILLS. MODEL
SOUNDINGS DO GENERATE SOME VERY MODEST CAPE VALUES...HOWEVER THEY
ALSO HAVE A WEAK UPPER LVL CAP IN PLACE MOST OF THE DAY/EVENING.
POPS RAMP UP STEADILY EARLY SUN AS THE DEEPER LAYER MOISTURE MOVES
INTO THE REGION...BUT I DO NOT CARRY ANY VALUES GREATER THAN HIGH END
CHANCE THRU 12Z SUN. TEMPS WILL START OUT WELL ABOVE CLIMO ON SAT
BEGIN TO DECREASE AS CLOUD COVER OVERSPREADS THE REGION ON SUN.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 125 PM EDT THURSDAY...MAIN FOCUS FOR THIS PERIOD OF THE
FORECAST WILL BE THE IMPACTS OF THE REMNANTS OF TS KAREN. THERE IS
STILL QUITE A BIT OF MODEL SPREAD IN REGARD TO THE SPECIFIC TRACK.
THE LATEST OFFICIAL NHC FORECAST BRINGS KAREN ONSHORE NEAR PENSACOLA
AT 12Z SUNDAY AND THEN MOVE THE STORM NE INTO UPSTATE SC BY 12Z
MONDAY. THE 12Z GFS FORECAST IS FARTHER EAST WITH THE TRACK...WHILE
THE 12Z CMC IS MUCH FARTHER WEST WIT TGHE LANDFALL (NEAR NEW
ORLEANS) AND THEN TAKES A HARD RIGHT ACROSS THE DEEP SOUTH TO SC ON
MON. THE 00Z ECM IS A LITTLE WEST OF THE NHC TRACK BUT THE MOST
SIMLAR TO THE NHC FORECAST ANDE ALSO THE MOST CONSISTENT.
REGARDLESS OF THE SPECIFICS...THE CIPS ANALOGS INDICATE A VERY HIGH
PROBABLILITY OF 2 PLUS INCHES OF RAIN ACROSS NE GA/WESTERN
CAROLINAS CIRCA 7 OCT. WPC AND OUR LOCAL CONS DATA HAVE CATEGORICAL
POPS FOR SUN NIGHT INTO MON. SEE NO REASON TO DEVIATE FROM THAT.
THERE MAY ALSO BE SOME VERY HEAVY RAIN. SPECIFIC STORM ANALOGS LIKE
TS HANNA IN SEPT 2002 THAT HAD A SIMILAR TRACK TO THE CURRENT NHC
TRACK PRODUCED 5-7 INCHES OF RAIN ACROSS THE WESTERN UPSSTATE AND
NE GA...WITH 1-3 INCHES ELSEWHERE. IF THE TRACK IS SIMILAR TO THE
CURRENT 12Z GFS WITH AN ANOLOG OF TS HELENE IN SEPT 2000 (A TRACK
ACROSS THE SC MIDLANDS). GENERALLY 1-3 INCHES OF RAIN FELL ACROSS
UPSTATE SC WITH AORUND 1 INCH ELSEWHERE. IT APPEARS THAT HEAVY RAIN
WILL CONTINUE TO BE THE MAIN THREAT IN THE WESTERN CAROLINAS AND NE
GA. HENCE WILL CONTINUE TO MENTION THAT IN THE HWO.
OTHERWISE...EXPECT SOME LINGERING SHOWERS/THUNDERSTORMS MON NIGHT
INTO TUE AS THE TRAILING SOUTHERN STREAM UPPER LOW/TROUGH CROSSES THE
AREA. HIGH PRESSURE IS THEN FORECAST TO RIDGE OVER THE AREA FROM THE
NORTH WED AND THU. TEMPS SHOUDL BE NEAR TO SLIGHT ABOVE AVERAGE.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...CONDITIONS ACROSS THE KCLT TERMINAL WILL LIKELY REMAIN VFR
THROUGH THE 18Z TAF PERIOD. BROAD SFC HIGH PRESSURE WILL LINGER
ACROSS THE PIEDMONT THROUGH FRIDAY. WINDS SHOULD REMAIN LIGHT FROM
THE SW THROUGH THIS EVENING...THEN CALM OVERNIGHT. A FEW PATCHES OF
FOG OR GROUND FOG IS POSSIBLE BETWEEN 10Z TO 13Z...LIMITING VIS TO
6SM. WINDS COULD REMAIN CALM FOR MOST OF FRIDAY MORNING...BUT
MEASURABLE WIND SHOULD FAVOR THE NW AROUND 3 KTS. CU SHOULD REMAIN
BETWEEN 060-070...WITH SCT CIRRUS.
ELSEWHERE...CONDITIONS WILL REMAIN VERY SIMILAR TO KCLT.
HOWEVER...CONDITIONS APPEAR FAVORABLE FOR VALLEY FOG LATE TONIGHT.
KAVL SHOULD SEE A CROSSOVER TEMPERATURE IN THE MID 50S...LIKELY
EXCEEDED BY SEVERAL DEGREES. I WILL TIME MVFR FOG BY
11Z...HIGHLIGHTING DENSE FOG AND LOW CEILINGS IN A TEMPO FROM 11Z TO
13Z. KAVL CONDITIONS SHOULD RETURN TO VFR BY 15Z. ELSEWHERE...I WILL
INCLUDE A TEMPO FOR 6 SM BR BETWEEN 10Z TO 13Z. WINDS WILL REMAIN
LIGHT TO CALM THROUGH THE PERIOD.
OUTLOOK...SFC HIGH PRESSURE WILL LINGER THROUGH SAT. MOISTURE
ASSOCIATED WITH TS KAREN WILL INCREASE ACROSS THE WESTERN CAROLINAS
AS COLD FRONT APPROACHES ON SUNDAY. THE REMNANT OF KAREN WILL TRACK
ACROSS OR IN THE VICINITY OF THE CAROLINA PIEDMONT EARLY NEXT WEEK.
THE BEST CHANCE OF WIDESPREAD RESTRICTIONS APPEARS TO BE SUNDAY
NIGHT INTO MONDAY.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 95% HIGH 91%
KGSP HIGH 100% HIGH 100% HIGH 95% HIGH 91%
KAVL HIGH 100% HIGH 100% HIGH 86% HIGH 84%
KHKY HIGH 100% HIGH 100% HIGH 95% HIGH 91%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 95% HIGH 91%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG/HG
NEAR TERM...NED
SHORT TERM...CDG
LONG TERM...JPT
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1103 AM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL PASS BY ALONG THE MOUNTAINS
TODAY....BUT WITH HIGH PRESSURE OTHERWISE REMAINING ACROSS THE
REGION THROUGH SATURDAY. A COLD FRONT...POSSIBLY ENHANCED WITH
TROPICAL MOISTURE...WILL APPROACH FROM THE WEST ON SUNDAY EVENING
AND BRING UNSETTLED AND RAINY WEATHER TO THE AREA FOR SUNDAY NIGHT
THROUGH MONDAY. HIGH PRESSURE WILL RETURN BEHIND THE PASSING
DISTURBANCE ON TUESDAY AND STRENGTHEN THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 11 AM...I HAVE ISSUED A QUICK UPDATE TO ADJUST SKY AND TEMP IN
LINE WITH LATEST OBSERVATIONS. KGSP RADAR CONTINUES TO INDICATE WEAK
RETURNS ACROSS THE NC MTNS...I WILL MAINTAIN SCHC POPS.
AS OF 700 AM EDT...KGSP RADAR CONTINUES TO SHOW SPORADIC 20 TO 25
DBZ ECHOES ALONG MAINLY THE SPINE OF THE SOUTHERN APPALACHIANS AT
DAYBREAK. ADDITIONAL WEAK FORCING FROM UPPER WAVES PASSING ALONG THE
NC/TN BORDER MAY DRIVE VERY LIGHT ISOLD RAIN SHOWERS...BUT ANY
PRECIP SHOULD BE CONFINED TO MAINLY THE HIGHER ELEVATIONS AND THE
FAR WRN MTNS. THE CURRENTLY PASSING SHORTWAVE WILL LIFT NWD THROUGH
THE CENTRAL APPALACHIANS TODAY...FOLLOWED BY A TRAILING SHORTWAVE
INTO THE AFTN HOURS. MAINLY MID AND HIGH LEVEL CLOUDS WILL CONTINUE
E OF THESE WAVES FOR A GOOD PART OF THE DAY. THE NAM CONTINUES TO
SHOW MORE ROBUST QPF OVER THE MTNS TODAY...ATTRIBUTED MAINLY TO LESS
CAPPING IN THE PROFILES. THIS APPEARS TO BE OVERDONE IN COMPARISON
TO THE OTHER NUMERICAL MODELS...SO WILL LEAN STRONGLY TOWARD THE
DRIER GFS AND RAP SOLUTIONS...WITH ONLY ISOLATED SHOWERS ALONG THE
MTN CHAIN AND DRY CONDITIONS EAST. DESPITE THE ABUNDANT MID/HIGH
CLOUDS...LOW LEVEL THICKNESSES WILL REACH OR SURPASS YESTERDAY
VALUES...WITH COMPARABLE MAXES OR TEMPS POSSIBLY A DEGREE WARMER IN
ERN SECTIONS.
FLAT RIDGING WILL THEN REDEVELOP BEHIND THE DEPARTING WAVES TONIGHT.
THE OPERATIONAL MOS IS QUITE COOL FOR MIN TEMPS...BUT WILL LEAN
HEAVILY TOWARD THE WARMER BIAS CORRECTED VALUES AS THE AIRMASS
CONTINUES TO MODIFY. ANOTHER ROUND OF EARLY MORNING MOUNTAIN VALLEY
CAN BE EXPECTED OVERNIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 120 AM EDT THURSDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
FORECAST FOR THE SHORT TERM PERIOD. WEAK DEEP LAYER RIDGING WILL
PREVAIL THROUGH SATURDAY KEEPING CONDITIONS MOSTLY SUNNY AND DRY.
MODEL GUIDANCE STILL CONTINUES TO INDICATE A FEW SHOWERS ALONG THE
RIDGETOPS WHERE CAPPING WILL BE WEAKEST. THUS KEPT MENTION OF
SLIGHT CHANCE POPS IN THE FORECAST FOR BOTH FRIDAY AND SATURDAY
ACROSS THE HIGH TERRAIN. MEANWHILE...POTENTIAL TROPICAL DISTURBANCE
WILL BE TAKING SHAPE IN THE CENTRAL GULF WHILE AN UPPER TROF MOVES
ACROSS THE NORTHERN PLAINS. ASSOCIATED SURFACE COLD FRONT WILL
CROSS THE MISSISSIPPI RIVER VALLEY LATE IN THE PERIOD SETTING UP
ACTIVE WEATHER FOR THE REMAINDER OF THE WEEKEND INTO THE START OF
THE WORK WEEK. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL BE
ABOVE NORMAL AS HIGH PRESSURE SUBSIDENCE KEEPS SKY COVER LIMITED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 225 AM EDT THURSDAY...MUCH UNCERTAINTY STILL REMAINS REGARDING
DEVELOPING TROPICAL CYCLONE IN THE CENTRAL GULF. LATEST NHC
GUIDANCE INDICATES A LARGE AREA OF CONVECTION NEAR THE YUCATAN
PENINSULA WITH FLIGHT INFO FROM THE DISTURBANCE YIELDING INDICATIONS
OF GALE FORCE WINDS...BUT NO CLOSED LOW AT THIS TIME.
TROPICAL FORECAST MODELS CONTINUE TO CONVERGE THEIR SOLUTIONS ON A
LOW TRACK THROUGH GEORGIA AND NORTHEAST ALONG AND JUST WEST OF THE
I85 CORRIDOR BY MONDAY. OPERATIONAL MODELS SUCH AS THE GFS/ECMWF
CONTINUE TO HAVE SLIGHT DIFFERENCES ON TIMING AND INTENSITY OF THIS
SYSTEM...AND ITS INTERACTION WITH THE PROGRESSIVE UPPER TROF AND
ASSOCIATED COLD FRONT THAT WILL BE MOVING THROUGH THE MISSISSIPPI
RIVER VALLEY SATURDAY NIGHT THROUGH SUNDAY. THE GFS CONTINUES TO
PRODUCE THE MOST IMPRESSIVE SOLUTION WITH A WELL DEFINED TROPICAL
FEATURE MAKING LANDFALL ALONG THE FLORIDA PANHANDLE LATE ON SUNDAY
NIGHT. AS THE UPPER TROF FEATURE CONTINUES EASTWARD...THE TROPICAL
LOW LOOKS TO ACCELERATE OUT AHEAD CROSSING THE DEEP SOUTH INTO THE
CAROLINAS BY MONDAY MORNING AS THE FROPA PUSHES INTO THE HIGHER
TERRAIN. THE ECMWF HAS A WEAKER AND SLIGHTLY SLOWER SOLUTION THAN
THE ABOVE MENTIONED GFS. EITHER WAY ITS TOO EARLY TO TELL WITH NEAR
ABSOLUTE CERTAINTY WHERE THE TRACK OF THE TROPICAL LOW AND ITS
ASSOCIATED MOISTURE WILL PASS. THIS TRACK WILL BE CRUCIAL TO
DETERMINE THE APPROXIMATE THREATS ACROSS NORTHEAST GA AND THE
CAROLINAS. AT THIS TIME USING A CONSENSUS OF TROPICAL MODEL OUTPUT
BACKED UP BY THE OPERATIONAL GFS AND CMC...IT LOOKS AS IF THE
PRIMARY THREATS WILL BE HEAVY RAINFALL WITH THE PRECIPITATION AXIS
MAXIMIZED ALONG THE I85 CORRIDOR. A MARGINAL SEVERE THREAT REMAINS
ACROSS AREAS EAST OF THE I85/I77 CORRIDORS WITH THIS CURRENT TRACK
ON MONDAY. IF THE SYSTEM STARTS TO DEVELOP EXTRATROPICAL FEATURES
AND BEGINS TO INTERACT MORE WITH THE FROPA...OR THE TRACK SHIFTS
SLIGHTLY WEST...THE PRECIPITATION AXIS COULD SHIFT WESTWARD ALSO
THEREBY INCREASING THE POTENTIAL FOR HEAVY RAINFALL ACROSS THE
MOUNTAINS. AS FOR THE FCST...INCREASING POPS LATE ON SUNDAY NIGHT
WILL EVENTUALLY SETUP SOLID LIKELY POPS ACROSS THE REGION ON
MONDAY. TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL AS MOSTLY
CLOUDY SKIES PREVAIL.
BEHIND THE PASSING SYSTEM ON TUESDAY...THE GFS SOLUTION EJECTS THE
TROPICAL LOW UP THE EAST COAST WITH THE COLD FRONT PROGRESSING OUT
TO SEA. HIGH PRESSURE THEN BUILDS IN ACROSS THE EASTERN GREAT LAKES
BY TUESDAY EVENING STRENGTHENING THROUGH MIDWEEK. THE ECMWF
SOLUTION PLAYS OUT MUCH DIFFERENTLY WITH THE TROPICAL SYSTEM
EJECTING AS IN THE GFS...YET THE SURFACE FRONT STALLS AS UPPER LEVEL
RIDGING OVER THE WESTERN ATLANTIC HOLDS FIRM. AT THIS RANGE...WENT
WITH A BLEND OF THE TWO SOLUTIONS THROUGH THE REMAINDER OF THE
PERIOD YIELDING LOW END CHANCE POPS AND NEAR NORMAL TEMPERATURES FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT...MID AND HIGH CLOUDS ARE SHOWING SIGNS OF CLEARING FROM THE
SOUTH AROUND DAYBREAK...AND SOME BRIEF FOG COULD STILL BE OBSERVED.
WILL ONLY FEATURE TEMPO 6SM BR AT THIS POINT. CALM WINDS WILL
GRADUALLY BECOME SOUTHERLY WITH MIXING BY LATE MORNING. ANY
LINGERING HIGH CLOUDS SHOULD EVENTUALLY GIVE WAY TO SCT
STRATOCUMULUS THROUGH THE DAY AS HEATING DEVELOPS. LIGHT S TO SW TO
CALM WINDS WILL LINGER OVERNIGHT...WITH FEW STRATOCUMULUS...AND A
LOW END THREAT OF MVFR FOG TOWARD DAYBREAK FRI.
ELSEWHERE...FOG DEVELOPMENT REMAINS FAIRLY TRANSIENT THIS MORNING
DUE TO THE PASSING MID AND HIGH CLOUDS ALOFT. ANTICIPATE THAT THE
BEST CHANCE OF TEMPO IFR TO LIFR CIG OR VSBY WILL BE AT KAVL AND
KAND THROUGH 14Z. OTHERWISE...LIGHT WINDS WILL BECOME SRLY THROUGH
THE DAY...WITH HIGH CLOUDS GRADUALLY GIVING WAY TO SCT
STRATOCUMULUS. ANY SPOTTY SHOWERS THROUGH THE DAY WILL BE CONFINED
TO THE FAR WRN MTNS AND WILL NOT BE MENTIONED IN THE TAFS. VFR
CONDITIONS WILL CONTINUE THROUGH THE EVENING HOURS WITH WINDS
BECOMING LIGHT ONCE AGAIN. MVFR VSBY IN FOG IS LIKELY AT THE
FOOTHILL TAFS OVERNIGHT...WITH IFR AT KAVL EARLY FRI MORNING.
.OUTLOOK...SFC HIGH PRESSURE WILL LINGER THROUGH SAT. MOISTURE WILL
INCREASE AHEAD OF AN APPROACHING COLD FRONT ON SUNDAY...WITH A
TROPICAL WEATHER FEATURE POSSIBLY MOVING NWD FROM THE GULF OF MEXICO
THROUGH MONDAY. THE BEST CHANCE OF WIDESPREAD RESTRICTIONS APPEARS
TO BE SUNDAY NIGHT INTO MONDAY.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 93% HIGH 100% HIGH 93% MED 75%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG/HG
NEAR TERM...NED
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
713 AM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL PASS BY ALONG THE MOUNTAINS
TODAY....BUT WITH HIGH PRESSURE OTHERWISE REMAINING ACROSS THE
REGION THROUGH SATURDAY. A COLD FRONT...POSSIBLY ENHANCED WITH
TROPICAL MOISTURE...WILL APPROACH FROM THE WEST ON SUNDAY EVENING
AND BRING UNSETTLED AND RAINY WEATHER TO THE AREA FOR SUNDAY NIGHT
THROUGH MONDAY. HIGH PRESSURE WILL RETURN BEHIND THE PASSING
DISTURBANCE ON TUESDAY AND STRENGTHEN THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM EDT...KGSP RADAR CONTINUES TO SHOW SPORADIC 20 TO 25
DBZ ECHOES ALONG MAINLY THE SPINE OF THE SOUTHERN APPALACHIANS AT
DAYBREAK. ADDITIONAL WEAK FORCING FROM UPPER WAVES PASSING ALONG THE
NC/TN BORDER MAY DRIVE VERY LIGHT ISOLD RAIN SHOWERS...BUT ANY
PRECIP SHOULD BE CONFINED TO MAINLY THE HIGHER ELEVATIONS AND THE
FAR WRN MTNS. THE CURRENTLY PASSING SHORTWAVE WILL LIFT NWD THROUGH
THE CENTRAL APPALACHIANS TODAY...FOLLOWED BY A TRAILING SHORTWAVE
INTO THE AFTN HOURS. MAINLY MID AND HIGH LEVEL CLOUDS WILL CONTINUE
E OF THESE WAVES FOR A GOOD PART OF THE DAY. THE NAM CONTINUES TO
SHOW MORE ROBUST QPF OVER THE MTNS TODAY...ATTRIBUTED MAINLY TO LESS
CAPPING IN THE PROFILES. THIS APPEARS TO BE OVERDONE IN COMPARISON
TO THE OTHER NUMERICAL MODELS...SO WILL LEAN STRONGLY TOWARD THE
DRIER GFS AND RAP SOLUTIONS...WITH ONLY ISOLATED SHOWERS ALONG THE
MTN CHAIN AND DRY CONDITIONS EAST. DESPITE THE ABUNDANT MID/HIGH
CLOUDS...LOW LEVEL THICKNESSES WILL REACH OR SURPASS YESTERDAY
VALUES...WITH COMPARABLE MAXES OR TEMPS POSSIBLY A DEGREE WARMER IN
ERN SECTIONS.
FLAT RIDGING WILL THEN REDEVELOP BEHIND THE DEPARTING WAVES TONIGHT.
THE OPERATIONAL MOS IS QUITE COOL FOR MIN TEMPS...BUT WILL LEAN
HEAVILY TOWARD THE WARMER BIAS CORRECTED VALUES AS THE AIRMASS
CONTINUES TO MODIFY. ANOTHER ROUND OF EARLY MORNING MOUNTAIN VALLEY
CAN BE EXPECTED OVERNIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 120 AM EDT THURSDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
FORECAST FOR THE SHORT TERM PERIOD. WEAK DEEP LAYER RIDGING WILL
PREVAIL THROUGH SATURDAY KEEPING CONDITIONS MOSTLY SUNNY AND DRY.
MODEL GUIDANCE STILL CONTINUES TO INDICATE A FEW SHOWERS ALONG THE
RIDGETOPS WHERE CAPPING WILL BE WEAKEST. THUS KEPT MENTION OF
SLIGHT CHANCE POPS IN THE FORECAST FOR BOTH FRIDAY AND SATURDAY
ACROSS THE HIGH TERRAIN. MEANWHILE...POTENTIAL TROPICAL DISTURBANCE
WILL BE TAKING SHAPE IN THE CENTRAL GULF WHILE AN UPPER TROF MOVES
ACROSS THE NORTHERN PLAINS. ASSOCIATED SURFACE COLD FRONT WILL
CROSS THE MISSISSIPPI RIVER VALLEY LATE IN THE PERIOD SETTING UP
ACTIVE WEATHER FOR THE REMAINDER OF THE WEEKEND INTO THE START OF
THE WORK WEEK. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL BE
ABOVE NORMAL AS HIGH PRESSURE SUBSIDENCE KEEPS SKY COVER LIMITED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 225 AM EDT THURSDAY...MUCH UNCERTAINTY STILL REMAINS REGARDING
DEVELOPING TROPICAL CYCLONE IN THE CENTRAL GULF. LATEST NHC
GUIDANCE INDICATES A LARGE AREA OF CONVECTION NEAR THE YUCATAN
PENINSULA WITH FLIGHT INFO FROM THE DISTURBANCE YIELDING INDICATIONS
OF GALE FORCE WINDS...BUT NO CLOSED LOW AT THIS TIME.
TROPICAL FORECAST MODELS CONTINUE TO CONVERGE THEIR SOLUTIONS ON A
LOW TRACK THROUGH GEORGIA AND NORTHEAST ALONG AND JUST WEST OF THE
I85 CORRIDOR BY MONDAY. OPERATIONAL MODELS SUCH AS THE GFS/ECMWF
CONTINUE TO HAVE SLIGHT DIFFERENCES ON TIMING AND INTENSITY OF THIS
SYSTEM...AND ITS INTERACTION WITH THE PROGRESSIVE UPPER TROF AND
ASSOCIATED COLD FRONT THAT WILL BE MOVING THROUGH THE MISSISSIPPI
RIVER VALLEY SATURDAY NIGHT THROUGH SUNDAY. THE GFS CONTINUES TO
PRODUCE THE MOST IMPRESSIVE SOLUTION WITH A WELL DEFINED TROPICAL
FEATURE MAKING LANDFALL ALONG THE FLORIDA PANHANDLE LATE ON SUNDAY
NIGHT. AS THE UPPER TROF FEATURE CONTINUES EASTWARD...THE TROPICAL
LOW LOOKS TO ACCELERATE OUT AHEAD CROSSING THE DEEP SOUTH INTO THE
CAROLINAS BY MONDAY MORNING AS THE FROPA PUSHES INTO THE HIGHER
TERRAIN. THE ECMWF HAS A WEAKER AND SLIGHTLY SLOWER SOLUTION THAN
THE ABOVE MENTIONED GFS. EITHER WAY ITS TOO EARLY TO TELL WITH NEAR
ABSOLUTE CERTAINTY WHERE THE TRACK OF THE TROPICAL LOW AND ITS
ASSOCIATED MOISTURE WILL PASS. THIS TRACK WILL BE CRUCIAL TO
DETERMINE THE APPROXIMATE THREATS ACROSS NORTHEAST GA AND THE
CAROLINAS. AT THIS TIME USING A CONSENSUS OF TROPICAL MODEL OUTPUT
BACKED UP BY THE OPERATIONAL GFS AND CMC...IT LOOKS AS IF THE
PRIMARY THREATS WILL BE HEAVY RAINFALL WITH THE PRECIPITATION AXIS
MAXIMIZED ALONG THE I85 CORRIDOR. A MARGINAL SEVERE THREAT REMAINS
ACROSS AREAS EAST OF THE I85/I77 CORRIDORS WITH THIS CURRENT TRACK
ON MONDAY. IF THE SYSTEM STARTS TO DEVELOP EXTRATROPICAL FEATURES
AND BEGINS TO INTERACT MORE WITH THE FROPA...OR THE TRACK SHIFTS
SLIGHTLY WEST...THE PRECIPITATION AXIS COULD SHIFT WESTWARD ALSO
THEREBY INCREASING THE POTENTIAL FOR HEAVY RAINFALL ACROSS THE
MOUNTAINS. AS FOR THE FCST...INCREASING POPS LATE ON SUNDAY NIGHT
WILL EVENTUALLY SETUP SOLID LIKELY POPS ACROSS THE REGION ON
MONDAY. TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL AS MOSTLY
CLOUDY SKIES PREVAIL.
BEHIND THE PASSING SYSTEM ON TUESDAY...THE GFS SOLUTION EJECTS THE
TROPICAL LOW UP THE EAST COAST WITH THE COLD FRONT PROGRESSING OUT
TO SEA. HIGH PRESSURE THEN BUILDS IN ACROSS THE EASTERN GREAT LAKES
BY TUESDAY EVENING STRENGTHENING THROUGH MIDWEEK. THE ECMWF
SOLUTION PLAYS OUT MUCH DIFFERENTLY WITH THE TROPICAL SYSTEM
EJECTING AS IN THE GFS...YET THE SURFACE FRONT STALLS AS UPPER LEVEL
RIDGING OVER THE WESTERN ATLANTIC HOLDS FIRM. AT THIS RANGE...WENT
WITH A BLEND OF THE TWO SOLUTIONS THROUGH THE REMAINDER OF THE
PERIOD YIELDING LOW END CHANCE POPS AND NEAR NORMAL TEMPERATURES FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
AT KCLT...MID AND HIGH CLOUDS ARE SHOWING SIGNS OF CLEARING FROM THE
SOUTH AROUND DAYBREAK...AND SOME BRIEF FOG COULD STILL BE OBSERVED.
WILL ONLY FEATURE TEMPO 6SM BR AT THIS POINT. CALM WINDS WILL
GRADUALLY BECOME SOUTHERLY WITH MIXING BY LATE MORNING. ANY
LINGERING HIGH CLOUDS SHOULD EVENTUALLY GIVE WAY TO SCT
STRATOCUMULUS THROUGH THE DAY AS HEATING DEVELOPS. LIGHT S TO SW TO
CALM WINDS WILL LINGER OVERNIGHT...WITH FEW STRATOCUMULUS...AND A
LOW END THREAT OF MVFR FOG TOWARD DAYBREAK FRI.
ELSEWHERE...FOG DEVELOPMENT REMAINS FAIRLY TRANSIENT THIS MORNING
DUE TO THE PASSING MID AND HIGH CLOUDS ALOFT. ANTICIPATE THAT THE
BEST CHANCE OF TEMPO IFR TO LIFR CIG OR VSBY WILL BE AT KAVL AND
KAND THROUGH 14Z. OTHERWISE...LIGHT WINDS WILL BECOME SRLY THROUGH
THE DAY...WITH HIGH CLOUDS GRADUALLY GIVING WAY TO SCT
STRATOCUMULUS. ANY SPOTTY SHOWERS THROUGH THE DAY WILL BE CONFINED
TO THE FAR WRN MTNS AND WILL NOT BE MENTIONED IN THE TAFS. VFR
CONDITIONS WILL CONTINUE THROUGH THE EVENING HOURS WITH WINDS
BECOMING LIGHT ONCE AGAIN. MVFR VSBY IN FOG IS LIKELY AT THE
FOOTHILL TAFS OVERNIGHT...WITH IFR AT KAVL EARLY FRI MORNING.
.OUTLOOK...SFC HIGH PRESSURE WILL LINGER THROUGH SAT. MOISTURE WILL
INCREASE AHEAD OF AN APPROACHING COLD FRONT ON SUNDAY...WITH A
TROPICAL WEATHER FEATURE POSSIBLY MOVING NWD FROM THE GULF OF MEXICO
THROUGH MONDAY. THE BEST CHANCE OF WIDESPREAD RESTRICTIONS APPEARS
TO BE SUNDAY NIGHT INTO MONDAY.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 65% HIGH 100% HIGH 100% HIGH 86%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 93% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG/HG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
454 AM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL PASS BY ALONG THE MOUNTAINS
TODAY....BUT WITH HIGH PRESSURE OTHERWISE REMAINING ACROSS THE
REGION THROUGH SATURDAY. A COLD FRONT...POSSIBLY ENHANCED WITH
TROPICAL MOISTURE...WILL APPROACH FROM THE WEST ON SUNDAY EVENING
AND BRING UNSETTLED AND RAINY WEATHER TO THE AREA FOR SUNDAY NIGHT
THROUGH MONDAY. HIGH PRESSURE WILL RETURN BEHIND THE PASSING
DISTURBANCE ON TUESDAY AND STRENGTHEN THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 445 AM EDT...KGSP RADAR IS SHOWING SPOTTY 20 TO 25 DBZ ECHOES
OVER THE SOUTHWEST NC MOUNTAINS EARLY THIS MORNING IN LOCATIONS IN
CLOSE PROXIMITY TO A PASSING UPPER SHORTWAVE LIFTING W OF THE MTNS.
SCHC POPS FOR LIGHT RAIN SHOWERS HAVE BEEN BOOSTED SLIGHTLY WITH TEH
LATEST UPDATE. THE FIRST SHORTWAVE WILL LIFT NWD THROUGH THE CENTRAL
APPALACHIANS TODAY...WITH A TRAILING SHORTWAVE THEN MOVING UP THE
SRN APPALACHIANS. MAINLY MID AND HIGH LEVEL CLOUDS WILL CONTINUE E
OF THE WAVES FOR A GOOD PART OF THE DAY. THE NAM HAS SURPRISINGLY
ROBUST QPF OVER THE MTNS TODAY...WITH PROFILES LOSING THE MID LEVEL
CAPPING INVERSION. THIS APPEARS TO BE OVERDONE IN COMPARISON TO THE
OTHER NUMERICAL MODELS...AND WILL LEAN STRONGLY TOWARD THE DRIER GFS
AND RAP SOLUTIONS...WITH ONLY ISOLATED SHOWERS ALONG THE MTN CHAIN
AND DRY CONDITIONS EAST. DESPITE THE ABUNDANT MID/HIGH CLOUDS...LOW
LEVEL THICKNESSES WILL REACH OR SURPASS YESTERDAY VALUES...WITH
COMPARABLE MAXES OR TEMPS POSSIBLY A DEGREE WARMER IN ERN SECTIONS.
FLAT RIDGING WILL THEN REDEVELOP BEHIND THE DEPARTING WAVES TONIGHT.
THE OPERATIONAL MOS IS QUITE COOL FOR MIN TEMPS...BUT WILL LEAN
HEAVILY TOWARD THE WARMER BIAS CORRECTED VALUES AS THE AIRMASS
CONTINUES TO MODIFY. ANOTHER ROUND OF EARLY MORNING MOUNTAIN VALLEY
CAN BE EXPECTED OVERNIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 120 AM EDT THURSDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
FORECAST FOR THE SHORT TERM PERIOD. WEAK DEEP LAYER RIDGING WILL
PREVAIL THROUGH SATURDAY KEEPING CONDITIONS MOSTLY SUNNY AND DRY.
MODEL GUIDANCE STILL CONTINUES TO INDICATE A FEW SHOWERS ALONG THE
RIDGETOPS WHERE CAPPING WILL BE WEAKEST. THUS KEPT MENTION OF
SLIGHT CHANCE POPS IN THE FORECAST FOR BOTH FRIDAY AND SATURDAY
ACROSS THE HIGH TERRAIN. MEANWHILE...POTENTIAL TROPICAL DISTURBANCE
WILL BE TAKING SHAPE IN THE CENTRAL GULF WHILE AN UPPER TROF MOVES
ACROSS THE NORTHERN PLAINS. ASSOCIATED SURFACE COLD FRONT WILL
CROSS THE MISSISSIPPI RIVER VALLEY LATE IN THE PERIOD SETTING UP
ACTIVE WEATHER FOR THE REMAINDER OF THE WEEKEND INTO THE START OF
THE WORK WEEK. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL BE
ABOVE NORMAL AS HIGH PRESSURE SUBSIDENCE KEEPS SKY COVER LIMITED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 225 AM EDT THURSDAY...MUCH UNCERTAINTY STILL REMAINS REGARDING
DEVELOPING TROPICAL CYCLONE IN THE CENTRAL GULF. LATEST NHC
GUIDANCE INDICATES A LARGE AREA OF CONVECTION NEAR THE YUCATAN
PENINSULA WITH FLIGHT INFO FROM THE DISTURBANCE YIELDING INDICATIONS
OF GALE FORCE WINDS...BUT NO CLOSED LOW AT THIS TIME.
TROPICAL FORECAST MODELS CONTINUE TO CONVERGE THEIR SOLUTIONS ON A
LOW TRACK THROUGH GEORGIA AND NORTHEAST ALONG AND JUST WEST OF THE
I85 CORRIDOR BY MONDAY. OPERATIONAL MODELS SUCH AS THE GFS/ECMWF
CONTINUE TO HAVE SLIGHT DIFFERENCES ON TIMING AND INTENSITY OF THIS
SYSTEM...AND ITS INTERACTION WITH THE PROGRESSIVE UPPER TROF AND
ASSOCIATED COLD FRONT THAT WILL BE MOVING THROUGH THE MISSISSIPPI
RIVER VALLEY SATURDAY NIGHT THROUGH SUNDAY. THE GFS CONTINUES TO
PRODUCE THE MOST IMPRESSIVE SOLUTION WITH A WELL DEFINED TROPICAL
FEATURE MAKING LANDFALL ALONG THE FLORIDA PANHANDLE LATE ON SUNDAY
NIGHT. AS THE UPPER TROF FEATURE CONTINUES EASTWARD...THE TROPICAL
LOW LOOKS TO ACCELERATE OUT AHEAD CROSSING THE DEEP SOUTH INTO THE
CAROLINAS BY MONDAY MORNING AS THE FROPA PUSHES INTO THE HIGHER
TERRAIN. THE ECMWF HAS A WEAKER AND SLIGHTLY SLOWER SOLUTION THAN
THE ABOVE MENTIONED GFS. EITHER WAY ITS TOO EARLY TO TELL WITH NEAR
ABSOLUTE CERTAINTY WHERE THE TRACK OF THE TROPICAL LOW AND ITS
ASSOCIATED MOISTURE WILL PASS. THIS TRACK WILL BE CRUCIAL TO
DETERMINE THE APPROXIMATE THREATS ACROSS NORTHEAST GA AND THE
CAROLINAS. AT THIS TIME USING A CONSENSUS OF TROPICAL MODEL OUTPUT
BACKED UP BY THE OPERATIONAL GFS AND CMC...IT LOOKS AS IF THE
PRIMARY THREATS WILL BE HEAVY RAINFALL WITH THE PRECIPITATION AXIS
MAXIMIZED ALONG THE I85 CORRIDOR. A MARGINAL SEVERE THREAT REMAINS
ACROSS AREAS EAST OF THE I85/I77 CORRIDORS WITH THIS CURRENT TRACK
ON MONDAY. IF THE SYSTEM STARTS TO DEVELOP EXTRATROPICAL FEATURES
AND BEGINS TO INTERACT MORE WITH THE FROPA...OR THE TRACK SHIFTS
SLIGHTLY WEST...THE PRECIPITATION AXIS COULD SHIFT WESTWARD ALSO
THEREBY INCREASING THE POTENTIAL FOR HEAVY RAINFALL ACROSS THE
MOUNTAINS. AS FOR THE FCST...INCREASING POPS LATE ON SUNDAY NIGHT
WILL EVENTUALLY SETUP SOLID LIKELY POPS ACROSS THE REGION ON
MONDAY. TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL AS MOSTLY
CLOUDY SKIES PREVAIL.
BEHIND THE PASSING SYSTEM ON TUESDAY...THE GFS SOLUTION EJECTS THE
TROPICAL LOW UP THE EAST COAST WITH THE COLD FRONT PROGRESSING OUT
TO SEA. HIGH PRESSURE THEN BUILDS IN ACROSS THE EASTERN GREAT LAKES
BY TUESDAY EVENING STRENGTHENING THROUGH MIDWEEK. THE ECMWF
SOLUTION PLAYS OUT MUCH DIFFERENTLY WITH THE TROPICAL SYSTEM
EJECTING AS IN THE GFS...YET THE SURFACE FRONT STALLS AS UPPER LEVEL
RIDGING OVER THE WESTERN ATLANTIC HOLDS FIRM. AT THIS RANGE...WENT
WITH A BLEND OF THE TWO SOLUTIONS THROUGH THE REMAINDER OF THE
PERIOD YIELDING LOW END CHANCE POPS AND NEAR NORMAL TEMPERATURES FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AT KCLT...CALM WINDS WILL CONTINUE THROUGH DAYBREAK...WITH
OCCASIONAL MID AND HIGH CLOUDS PASSING THROUGH THE REGION. THERE MAY
BE ENOUGH BREAKS FOR TEMPO MVFR FOG TO FORM AROUND SUNRISE AS
BOUNDARY LAYER MOISTURE CONTINUES TO RECOVER SLIGHTLY. EXPECT WINDS
TO SLOWLY INCREASE FROM THE S TO SW DURING THE DAY. THE HIGH CLOUDS
SHOULD EVENTUALLY GIVE WAY TO SCT STRATOCUMULUS AS HEATING DEVELOPS.
THE FORECAST WILL REMAIN DRY.
ELSEWHERE...THE FOG FORECAST FOR THE MTN AND FOOTHILL TAFS REMAINS
COMPLICATED DUE TO THE MID AND HIGH CLOUDS STREAMING ACROSS THE
REGION EAST OF SHORTWAVES PASSING THE WRN MTNS. INCREASING BL
MOISTURE...ALONG WITH OCCASIONAL BREAKS OR THIN SPOTS IN THE HIGHER
CLOUDS...SHOULD SUPPORT IFR CONDITIONS IN THE MTN VALLEYS AND TEMPO
MVFR FOG TOWARD DAYBREAK AT THE FOOTHILL SITES. EXPECT LIGHT TO CALM
WINDS EARLY TODAY...TOGGLING SOUTHERLY AND SLOWLY INCREASING THROUGH
THE DAY. ANY SPOTTY SHOWERS WILL BE CONFINED TO THE FAR WRN MTNS AND
WILL NOT BE MENTIONED IN THE TAFS. VFR CONDITIONS WILL CONTINUE
THROUGH THE EVENING HOURS WITH WINDS BECOMING LIGHT ONCE AGAIN.
.OUTLOOK...HIGH PRESSURE WILL LINGER THROUGH SAT. MOISTURE WILL
INCREASE AHEAD OF AN APPROACHING COLD FRONT ON SUNDAY...WITH A
TROPICAL WEATHER FEATURE POSSIBLY MOVING NWD FROM THE GULF OF MEXICO
AT THAT TIME. THE WETTEST PERIOD WITH MOST WIDESPREAD RESTRICTIONS
LOOKS TO BE MONDAY.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 91% HIGH 100% HIGH 100% HIGH 100%
KAVL LOW 58% HIGH 92% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 91% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG/HG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
237 AM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL PASS BY ALONG THE MOUNTAINS
TODAY....BUT WITH HIGH PRESSURE OTHERWISE REMAINING ACROSS THE
REGION THROUGH SATURDAY. A COLD FRONT...POSSIBLY ENHANCED WITH
TROPICAL MOISTURE...WILL APPROACH FROM THE WEST ON SUNDAY EVENING
AND BRING UNSETTLED AND RAINY WEATHER TO THE AREA FOR SUNDAY NIGHT
THROUGH MONDAY. HIGH PRESSURE WILL RETURN BEHIND THE PASSING
DISTURBANCE ON TUESDAY AND STRENGTHEN THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 220 AM EDT...WATER VAPOR IMAGERY SHOWS A SHORTWAVE LIFTING
THROUGH ERN TN EARLY THIS MORNING. SLIGHTLY BETTER MOISTURE AND LIFT
ON THE E SIDE OF THIS FEATURE WILL BRUSH THE SMOKIES AREAS THROUGH
DAYBREAK...AND SCHC POPS FOR LIGHT RAIN SHOWERS WILL BE WARRANTED
THERE. THE FIRST SHORTWAVE WILL LIFT NWD THROUGH THE CENTRAL
APPALACHIANS TODAY...WITH A TRAILING SHORTWAVE THEN MOVING UP THE
SRN APPALACHIANS. MAINLY MID AND HIGH LEVEL CLOUDS WILL CONTINUE E
OF THE WAVES FOR A GOOD PART OF THE DAY. THE NAM HAS SURPRISINGLY
ROBUST QPF OVER THE MTNS TODAY...WITH PROFILES LOSING THE MID LEVEL
CAPPING INVERSION. THIS APPEARS TO BE OVERDONE IN COMPARISON TO THE
OTHER NUMERICAL MODELS...AND WILL LEAN STRONGLY TOWARD THE DRIER GFS
AND RAP SOLUTIONS...WITH ONLY ISOLATED SHOWERS ALONG THE MTN CHAIN
AND DRY CONDITIONS EAST. DESPITE THE ABUNDANT MID/HIGH CLOUDS...LOW
LEVEL THICKNESSES WILL REACH OR SURPASS YESTERDAY VALUES...WITH
COMPARABLE MAXES OR TEMPS POSSIBLY A DEGREE WARMER IN ERN SECTIONS.
FLAT RIDGING WILL THEN REDEVELOP BEHIND THE DEPARTING WAVES TONIGHT.
THE OPERATIONAL MOS IS QUITE COOL FOR MIN TEMPS...BUT WILL LEAN
HEAVILY TOWARD THE WARMER BIAS CORRECTED VALUES AS THE AIRMASS
CONTINUES TO MODIFY. ANOTHER ROUND OF EARLY MORNING MOUNTAIN VALLEY
CAN BE EXPECTED OVERNIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 120 AM EDT THURSDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
FORECAST FOR THE SHORT TERM PERIOD. WEAK DEEP LAYER RIDGING WILL
PREVAIL THROUGH SATURDAY KEEPING CONDITIONS MOSTLY SUNNY AND DRY.
MODEL GUIDANCE STILL CONTINUES TO INDICATE A FEW SHOWERS ALONG THE
RIDGETOPS WHERE CAPPING WILL BE WEAKEST. THUS KEPT MENTION OF
SLIGHT CHANCE POPS IN THE FORECAST FOR BOTH FRIDAY AND SATURDAY
ACROSS THE HIGH TERRAIN. MEANWHILE...POTENTIAL TROPICAL DISTURBANCE
WILL BE TAKING SHAPE IN THE CENTRAL GULF WHILE AN UPPER TROF MOVES
ACROSS THE NORTHERN PLAINS. ASSOCIATED SURFACE COLD FRONT WILL
CROSS THE MISSISSIPPI RIVER VALLEY LATE IN THE PERIOD SETTING UP
ACTIVE WEATHER FOR THE REMAINDER OF THE WEEKEND INTO THE START OF
THE WORK WEEK. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL BE
ABOVE NORMAL AS HIGH PRESSURE SUBSIDENCE KEEPS SKY COVER LIMITED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 225 AM EDT THURSDAY...MUCH UNCERTAINTY STILL REMAINS REGARDING
DEVELOPING TROPICAL CYCLONE IN THE CENTRAL GULF. LATEST NHC
GUIDANCE INDICATES A LARGE AREA OF CONVECTION NEAR THE YUCATAN
PENINSULA WITH FLIGHT INFO FROM THE DISTURBANCE YIELDING INDICATIONS
OF GALE FORCE WINDS...BUT NO CLOSED LOW AT THIS TIME.
TROPICAL FORECAST MODELS CONTINUE TO CONVERGE THEIR SOLUTIONS ON A
LOW TRACK THROUGH GEORGIA AND NORTHEAST ALONG AND JUST WEST OF THE
I85 CORRIDOR BY MONDAY. OPERATIONAL MODELS SUCH AS THE GFS/ECMWF
CONTINUE TO HAVE SLIGHT DIFFERENCES ON TIMING AND INTENSITY OF THIS
SYSTEM...AND ITS INTERACTION WITH THE PROGRESSIVE UPPER TROF AND
ASSOCIATED COLD FRONT THAT WILL BE MOVING THROUGH THE MISSISSIPPI
RIVER VALLEY SATURDAY NIGHT THROUGH SUNDAY. THE GFS CONTINUES TO
PRODUCE THE MOST IMPRESSIVE SOLUTION WITH A WELL DEFINED TROPICAL
FEATURE MAKING LANDFALL ALONG THE FLORIDA PANHANDLE LATE ON SUNDAY
NIGHT. AS THE UPPER TROF FEATURE CONTINUES EASTWARD...THE TROPICAL
LOW LOOKS TO ACCELERATE OUT AHEAD CROSSING THE DEEP SOUTH INTO THE
CAROLINAS BY MONDAY MORNING AS THE FROPA PUSHES INTO THE HIGHER
TERRAIN. THE ECMWF HAS A WEAKER AND SLIGHTLY SLOWER SOLUTION THAN
THE ABOVE MENTIONED GFS. EITHER WAY ITS TOO EARLY TO TELL WITH NEAR
ABSOLUTE CERTAINTY WHERE THE TRACK OF THE TROPICAL LOW AND ITS
ASSOCIATED MOISTURE WILL PASS. THIS TRACK WILL BE CRUCIAL TO
DETERMINE THE APPROXIMATE THREATS ACROSS NORTHEAST GA AND THE
CAROLINAS. AT THIS TIME USING A CONSENSUS OF TROPICAL MODEL OUTPUT
BACKED UP BY THE OPERATIONAL GFS AND CMC...IT LOOKS AS IF THE
PRIMARY THREATS WILL BE HEAVY RAINFALL WITH THE PRECIPITATION AXIS
MAXIMIZED ALONG THE I85 CORRIDOR. A MARGINAL SEVERE THREAT REMAINS
ACROSS AREAS EAST OF THE I85/I77 CORRIDORS WITH THIS CURRENT TRACK
ON MONDAY. IF THE SYSTEM STARTS TO DEVELOP EXTRATROPICAL FEATURES
AND BEGINS TO INTERACT MORE WITH THE FROPA...OR THE TRACK SHIFTS
SLIGHTLY WEST...THE PRECIPITATION AXIS COULD SHIFT WESTWARD ALSO
THEREBY INCREASING THE POTENTIAL FOR HEAVY RAINFALL ACROSS THE
MOUNTAINS. AS FOR THE FCST...INCREASING POPS LATE ON SUNDAY NIGHT
WILL EVENTUALLY SETUP SOLID LIKELY POPS ACROSS THE REGION ON
MONDAY. TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL AS MOSTLY
CLOUDY SKIES PREVAIL.
BEHIND THE PASSING SYSTEM ON TUESDAY...THE GFS SOLUTION EJECTS THE
TROPICAL LOW UP THE EAST COAST WITH THE COLD FRONT PROGRESSING OUT
TO SEA. HIGH PRESSURE THEN BUILDS IN ACROSS THE EASTERN GREAT LAKES
BY TUESDAY EVENING STRENGTHENING THROUGH MIDWEEK. THE ECMWF
SOLUTION PLAYS OUT MUCH DIFFERENTLY WITH THE TROPICAL SYSTEM
EJECTING AS IN THE GFS...YET THE SURFACE FRONT STALLS AS UPPER LEVEL
RIDGING OVER THE WESTERN ATLANTIC HOLDS FIRM. AT THIS RANGE...WENT
WITH A BLEND OF THE TWO SOLUTIONS THROUGH THE REMAINDER OF THE
PERIOD YIELDING LOW END CHANCE POPS AND NEAR NORMAL TEMPERATURES FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AT KCLT...CALM WINDS WILL CONTINUE OVERNIGHT...WITH A FAIRLY THICK
BLANKET OF MID AND HIGH CLOUDS EXPECTED AT TIMES. THERE MAY BE JUST
ENOUGH BREAKS FOR TEMPO MVFR FOG TO FORM TOWARD DAYBREAK AS BOUNDARY
LAYER MOISTURE CONTINUES TO RECOVER SLIGHTLY. EXPECT WINDS TO SLOWLY
INCREASE FROM THE S TO SW DURING THE DAY. HIGH CLOUDS MAY GRADUALLY
THIN...WITH SCT FLATTENED CONVECTIVE CUMULUS DEVELOPING WITH
HEATING. THE FORECAST WILL REMAIN DRY.
ELSEWHERE...THE FOG FORECAST FOR THE MTN AND FOOTHILL TAFS WILL BE
GREATLY COMPLICATED BY THE MID AND HIGH CLOUDS STREAMING ACROSS THE
REGION EAST OF SHORTWAVES PASSING THE WRN MTNS. BL MOISTURE SLOWLY
INCREASING...ALONG WITH OCCASIONAL BREAKS OR THIN SPOTS IN THE
HIGHER CLOUDS...SHOULD SUPPORT SOLID IFR CONDITIONS IN THE MTN
VALLEYS AND TEMPO MVFR FOG TOWARD DAYBREAK AT THE FOOTHILL SITES.
EXPECT LIGHT TO CALM WINDS EARLY TODAY TO TOGGLE SOUTHERLY AND
SLOWLY INCREASE THROUGH THE DAY. ANY SPOTTY SHOWERS WILL BE CONFINED
TO THE FAR WRN MTNS AND WILL NOT BE MENTIONED IN THE TAFS. VFR
CONDITIONS WILL CONTINUE THROUGH THE EVENING HOURS WITH WINDS
BECOMING LIGHT ONCE AGAIN.
.OUTLOOK...HIGH PRESSURE WILL LINGER THROUGH SAT. MOISTURE WILL
INCREASE AHEAD OF AN APPROACHING COLD FRONT ON SUNDAY...WITH A
TROPICAL WEATHER FEATURE POSSIBLY MOVING NWD FROM THE GULF OF MEXICO
AT THAT TIME. THE WETTEST PERIOD WITH MOST WIDESPREAD RESTRICTIONS
LOOKS TO BE MONDAY.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 78% MED 72% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 91% HIGH 95% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG/HG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
213 AM EDT THU OCT 3 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL PASS BY ALONG THE MOUNTAINS
TODAY....BUT WITH HIGH PRESSURE OTHERWISE REMAINING ACROSS THE
REGION THROUGH SATURDAY. A COLD FRONT...POSSIBLY ENHANCED WITH
TROPICAL MOISTURE...WILL APPROACH FROM THE WEST ON SUNDAY EVENING
AND BRING UNSETTLED AND RAINY WEATHER TO THE AREA FOR SUNDAY NIGHT
THROUGH MONDAY. HIGH PRESSURE WILL RETURN BEHIND THE PASSING
DISTURBANCE ON TUESDAY AND STRENGTHEN THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 AM EDT...WATER VAPOR IMAGERY SHOWS A SHORTWAVE LIFTING
THROUGH ERN TN EARLY THIS MORNING. SLIGHTLY BETTER MOISTURE AND LIFT
ON THE E SIDE OF THIS FEATURE WILL BRUSH THE SMOKIES AREAS THROUGH
DAYBREAK...AND SCHC POPS FOR LIGHT RAIN SHOWERS WILL BE WARRANTED
THERE. THE FIRST SHORTWAVE WILL LIFT NWD THROUGH THE CENTRAL
APPALACHIANS TODAY...WITH A TRAILING SHORTWAVE THEN MOVING UP THE
SRN APPALACHIANS. MAINLY MID AND HIGH LEVEL CLOUDS WILL CONTINUE E
OF THE WAVES FOR A GOOD PART OF THE DAY. THE NAM HAS SURPRISINGLY
ROBUST QPF OVER THE MTNS TODAY...WITH PROFILES LOSING THE MID LEVEL
CAPPING INVERSION. THIS APPEARS TO BE OVERDONE IN COMPARISON TO THE
OTHER NUMERICAL MODELS...AND WILL LEAN STRONGLY TOWARD THE DRIER GFS
AND RAP SOLUTIONS...WITH ONLY ISOLATED SHOWERS ALONG THE MTN CHAIN
AND DRY CONDITIONS EAST. DESPITE THE ABUNDANT MID/HIGH CLOUDS...LOW
LEVEL THICKNESSES WILL REACH OR SURPASS YESTERDAY VALUES...WITH
COMPARABLE MAXES OR POSSIBLY A DEGREE WARMER IN ERN SECTIONS.
FLAT RIDGING WILL THEN REDEVELOP BEHIND THE DEPARTING WAVES TONIGHT.
THE OPERATIONAL MOS IS QUITE COOL FOR MIN TEMPS...BUT WILL LEAN
HEAVILY TOWARD THE WARMER BIAS CORRECTED VALUES AS THE AIRMASS
CONTINUES TO MODIFY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 120 AM EDT THURSDAY...NO SIGNIFICANT CHANGES FROM THE PREVIOUS
FORECAST FOR THE SHORT TERM PERIOD. WEAK DEEP LAYER RIDGING WILL
PREVAIL THROUGH SATURDAY KEEPING CONDITIONS MOSTLY SUNNY AND DRY.
MODEL GUIDANCE STILL CONTINUES TO INDICATE A FEW SHOWERS ALONG THE
RIDGETOPS WHERE CAPPING WILL BE WEAKEST. THUS KEPT MENTION OF
SLIGHT CHANCE POPS IN THE FORECAST FOR BOTH FRIDAY AND SATURDAY
ACROSS THE HIGH TERRAIN. MEANWHILE...POTENTIAL TROPICAL DISTURBANCE
WILL BE TAKING SHAPE IN THE CENTRAL GULF WHILE AN UPPER TROF MOVES
ACROSS THE NORTHERN PLAINS. ASSOCIATED SURFACE COLD FRONT WILL
CROSS THE MISSISSIPPI RIVER VALLEY LATE IN THE PERIOD SETTING UP
ACTIVE WEATHER FOR THE REMAINDER OF THE WEEKEND INTO THE START OF
THE WORK WEEK. TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL BE
ABOVE NORMAL AS HIGH PRESSURE SUBSIDENCE KEEPS SKY COVER LIMITED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 145 PM WEDNESDAY...STILL PLENTY OF UNCERTAINTY IN THE MEDIUM
RANGE ON THE DETAILS ASSOCIATED WITH A TROPICAL DISTURBANCE AND ITS
INTERACTION WITH A FRONTAL ZONE SUNDAY THRU TUESDAY. TIMING AND
TRACK DIFFERENCES AMONG THE MODEL SOLNS ARE SIMILAR TO WHAT THEY
WERE YESTERDAY. THE MAIN REASON FOR THIS IS THAT THERE IS STILL A
LOT OF MODEL SPREAD IN THE MID LATITUDE SYSTEM...AND THE TROPICAL
DISTURBANCE IS STILL WEAK (SO OP MODELS ARE TASKED TO FORECAST
TROPICAL CYCLOGENESIS RATHER THAN BEING INITIALIZED WITH A BOGUS
CIRCULATION). SO I/M FAIRLY CONFIDENT THINGS SHUD START CONVERGING
ONCE THE SYSTEM GETS A BIT BETTER ORGANIZED. SPEAKING OF...THE 2 PM
TROPICAL OUTLOOK FROM THE NHC HAS BUMPED UP THE PROBABILITY OF THE
SYSTEM BECOMING AT LEAST A TD TO 70 PCT WITHIN THE NEXT 48 HOURS. IT
CERTAINLY IS LOOKING BETTER ON SAT IMAGERY...AS IT APPROACHES THE
TIP OF THE YUCATAN. HOWEVER...ONCE IT ENTERS THE GULF OF MEXICO...IT
IS EXPECTED TO REMAIN IN MARGINAL...IF NOT UNFAVORABLE...
ENVIRONMENT FOR FURTHER STRENGTHENING.
IN ANY CASE...IT IS LOOKING MORE LIKELY THE TC OR WAVE WILL LIFT N
TO THE GULF COAST...THEN MERGE/INTERACT WITH A BAROCLINIC ZONE INVOF
THE SOUTHEAST STATES. THE 12Z GFS HAS COME IN RATHER STRONG WITH THE
LOW AND DEEPER WITH THE UPR TROF...RESULTING IN AN EXTRATROPICAL
TRANSITION SIGNATURE IN THE QPF SWATH. THE TRANSITION PLACES THE
HEAVY QPF RIGHT ACRS THE I-85 CORRIDOR SUNDAY NIGHT THRU MONDAY
(GENERALLY 2-4 INCHES)...AS THE LOW TRACKS NC ACRS THE MIDLANDS.
THIS OF COURSE IS STILL ONE OF MANY POSSIBLE SCENARIOS. I STILL
THINK THE HEAVY RAIN MENTION IN THE HWO LOOKS GOOD. AS FOR ANY
SEVERE THREAT...THAT IS STILL LESS CERTAIN THAN THE HEAVY RAIN
THREAT...AS EVEN THE STRONGER GFS KEEPS THE BEST INSTBY AND SHEAR
COUPLED TOGETHER TO OUR SOUTH AND EAST.
I BLENDED THE 12Z WPC GRIDS FOR THIS PACKAGE. TEMPS WILL BE ABOVE
NORMAL SUNDAY AHEAD OF THE SYSTEM...WITH JUST A SLGT CHC TO LOW-END
CHC POP CREEPING IN FROM THE SW LATE IN THE DAY. THEN BELOW NORMAL
HIGHS AND NEAR NORMAL LOWS MONDAY AND BEYOND. POPS WERE STILL CAPPED
AT LIKELY GIVEN THE LINGERING UNCERTAINTY ON TIMING.
TUESDAY AND WEDNESDAY...MODELS DIVERGE FURTHER AS A WRN ATLANTIC
RIDGE MAY BLOCK PROGRESSION OF THE FRONT AND RESULT IN LINGERING
UNSETTLED WX THRU MIDWEEK. WILL KEEP A SLGT CHC TO LOW-END CHC POP
IN FOR THESE PERIODS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...CALM WINDS WILL CONTINUE OVERNIGHT...WITH A FAIRLY THICK
BLANKET OF MID AND HIGH CLOUDS EXPECTED AT TIMES. THERE MAY BE JUST
ENOUGH BREAKS FOR TEMPO MVFR FOG TO FORM TOWARD DAYBREAK AS BOUNDARY
LAYER MOISTURE CONTINUES TO RECOVER SLIGHTLY. EXPECT WINDS TO SLOWLY
INCREASE FROM THE S TO SW DURING THE DAY. HIGH CLOUDS MAY GRADUALLY
THIN...WITH SCT FLAT CONVECTIVE CUMULUS DEVELOPING WITH HEATING. THE
FORECAST WILL REMAIN DRY.
ELSEWHERE...THE FOG FORECAST FOR THE MTN AND FOOTHILL TAFS WILL BE
GREATLY COMPLICATED BY THE MID AND HIGH CLOUDS STREAMING ACROSS THE
REGION EAST OF SHORTWAVES PASSING THE WRN MTNS. BL MOISTURE SLOWLY
INCREASING...ALONG WITH OCCASIONAL BREAKS OR THIN SPOTS IN THE
HIGHER CLOUDS...SHOULD SUPPORT SOLID IFR CONDITIONS IN THE MTN
VALLEYS AND TEMPO MVFR FOG TOWARD DAYBREAK AT THE FOOTHILL SITES.
EXPECT LIGHT TO CALM WINDS EARLY TODAY TO TOGGLE SOUTHERLY AND
SLOWLY INCREASE THROUGH THE DAY. ANY SPOTTY SHOWERS WILL BE CONFINED
TO THE FAR WRN MTNS AND NOT BE MENTIONED IN THE TAFS. VFR CONDITIONS
WILL CONTINUE THROUGH THE EVENING HOURS WITH WINDS BECOMING LIGHT
ONCE AGAIN.
.OUTLOOK...HIGH PRESSURE WILL LINGER THROUGH SAT. MOISTURE WILL
INCREASE AHEAD OF AN APPROACHING COLD FRONT ON SUNDAY...WITH A
TROPICAL WEATHER FEATURE POSSIBLY MOVING NWD FROM THE GULF OF MEXICO
AT THAT TIME. THE WETTEST PERIOD WITH MOST WIDESPREAD RESTRICTIONS
LOOKS TO BE MONDAY.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 78% MED 72% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 91% HIGH 95% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CDG/HG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...ARK
AVIATION...HG
AREA FORECAST DISCUSSION...CORRECTED
NWS ABERDEEN SD
1054 AM CDT FRI OCT 4 2013
.UPDATE...
SCATTERED/NUMEROUS SHOWERS ALONG WITH A FEW THUNDERSTORMS WERE
LIFTING NORTH ACROSS MAINLY CENTRAL AND NORTH CENTRAL SOUTH DAKOTA
LATE THIS MORNING. ALSO...REPORTS IN WESTERN CORSON OF THE RAIN
CHANGING OVER TO SNOW. THE LATEST HRRR RUN SHOWS MORE
SHOWERS/THUNDERSTORMS DEVELOPING THIS AFTERNOON/EARLY EVENING
ALONG DRY SLOT LIFTING NORTHWARD IN THE DEEPENING UPPER LOW
PRESSURE AREA. ADDED SNOW OR RAIN/SNOW TO THE FAR WESTERN COUNTIES
THROUGH THE AFTERNOON. THE OTHER ISSUE IS THE STRONG WINDS ALREADY
OCCURRING. THE LATEST MODEL RUNS AND GUIDANCE SHOW THESE STRONG
WINDS CONTINUING THROUGH THE AFTERNOON AND NIGHT. WINDS MAY BE
CLOSE TO HIGH WINDS AT TIMES. WILL LEAVE WIND ADVISORY GOING
THROUGH THE NIGHT AND MAY HAVE TO EXTEND THIS EVEN THROUGH
SATURDAY. NOT MUCH CHANGE IN TEMPERATURES THROUGH THE AFTERNOON
WITH CLOUD COVER AND PRECIPITATION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
HEADLINES OVER THE NEXT 24 TO 30 HOURS WILL BE THE MAIN FORECAST
CHALLENGE.
MODELS ARE IN A REASONABLE AGREEMENT THIS MORNING WITH THE
HANDLING OF THE FIRST SNOWSTORM OF THE SEASON. ISENTROPIC UPGLIDE
IS CURRENTLY ONGOING OVER WESTERN SOUTH DAKOTA WHERE WIDESPREAD
LIGHT TO MODERATE RAIN IS OCCURRING. SO FAR ONLY THE HIGHER
TERRAIN AREAS OF THE BLACK HILLS AND EASTERN WYOMING HAS
TRANSITIONED OVER TO ALL SNOW. WITH LIMITED CAA...WAA AT H7...NOT
TOO SURPRISED TO SEE A SLOW TRANSITION OVER TO SNOW. THE 0Z MODEL
RUNS OF THE GFS/NAM/HI-RES ARW ALL SUGGEST LITTLE TO NO SNOW FOR
LOCATIONS ALONG AND EAST OF THE MISSOURI RIVER FOR THIS EVENT. A
FEW MODELS ACTUALLY SHOW KPIR CHANGING OVER TO SNOW SEVERAL HOURS
BEFORE KMBG DOES DUE TO THE PLACEMENT OF THE H5 LOW PRESSURE.
THERE WILL DEFINITELY BE A FINE LINE BETWEEN SIGNIFICANT SNOW
ACCUMULATIONS AND NO SNOWFALL. WITH THE CENTRAL AND WESTERN
PORTIONS OF CORSON AND DEWEY COUNTY SEEING A MORE PROLONGED TIME
PERIOD OF SNOW...HAVE UPGRADED THESE COUNTIES TO A WINTER STORM
WARNING. SINCE SNOW WILL BE DELAYED ELSEWHERE...WILL PUSH THE
WINTER STORM WATCH BACK UNTIL 0Z.
FURTHER EAST...MODELS HAVE DEVELOPED A NOTICEABLE DRY SLOT MOVING
ACROSS THE EASTERN CWA AFTER 6Z SATURDAY. THE CONSENSUS AMONG
MODELS WITH REGARDS TO QPF IS DRASTICALLY LOWER THAN THE PREVIOUS
FORECAST. MODEL SOUNDINGS ARE MORE SUPPORTIVE OF CONTINUOUS DRIZZLE
THAN MODERATE RAINFALL. HAVE LEFT OUT THE MENTION OF DRIZZLE FOR
NOW HOWEVER.
IT HAS BEEN NOTED FOR A WHILE NOW THAT IS STORM SYSTEM WILL BRING
VERY STRONG NORTHERLY WINDS WITH GUSTS AROUND 50 MPH POSSIBLE. THE
PREVIOUS FORECAST SHIFT HAD ALREADY ISSUED A WIND ADVISORY WHICH
LOOKS REALLY GOOD. BASED ON THE GFS LAMP GUIDANCE...HAVE DECIDED
TO ADD BROWN COUNTY INTO THE ADVISORY...AND HAVE EXTENDED THE
ADVISORY IN TIME UNTIL 12Z SATURDAY. CONDITIONS SHOULD GRADUALLY
IMPROVE DURING THE AFTERNOON HOURS ON SATURDAY FROM WEST TO EAST.
.LONG TERM...SUNDAY THROUGH FRIDAY
A QUIET PERIOD EXPECTED AFTER THE LOW CURRENTLY AFFECTING THE
PLAINS EXITS THIS CWA SUNDAY MORNING. UPPER RIDGING AND A SURFACE
BASED LEE SIDE TROUGH WILL MOVE IN FROM THE WEST ON MONDAY AND
TEMPERATURES WILL REBOUND NICELY WITH EXPECTED HIGHS IN THE 60S
THROUGH THE WEEK. WEAK SFC LOW PRESSURE WILL SPREAD OVER THE
REGION BY WED BUT WILL BE MOISTURE STARVED INITIALLY. AS ANOTHER
UPPER TROF MOVES IN THU NIGHT/FRIDAY AND A WELL STACKED LOW
DEVELOPS OVER THE PLAINS PRECIP CHANCES INCREASE.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
RAIN IS EXPECTED TO CONTINUE TO SPREAD ACROSS THE REMAINDER OF
THE REGION TODAY. CURRENT CIGS AND VSBYS REMAIN IN THE VFR TO MVFR
CATEGORIES...WITH THE EXCEPTION OF KATY WHERE A 300 FT STRATUS
DECK IS ALREADY IN PLACE. CIGS ARE EXPECTED TO FALL TO IFR AT ALL
SITES AS HEAVIER PRECIP MOVES IN. NORTHERLY WINDS WILL INCREASE
TODAY TO 25 TO 35 KTS WITH HIGHER GUSTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SATURDAY FOR BROWN-
BUFFALO-CAMPBELL-CORSON-DEWEY-EDMUNDS-FAULK-HAND-HUGHES-
HYDE-JONES-LYMAN-MCPHERSON-POTTER-STANLEY-SULLY-WALWORTH.
WINTER STORM WATCH FROM 7 PM CDT /6 PM MDT/ THIS EVENING THROUGH
SATURDAY AFTERNOON FOR CAMPBELL-HUGHES-JONES-POTTER-STANLEY-
SULLY-WALWORTH.
WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR CORSON-DEWEY.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...WISE
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1053 AM CDT FRI OCT 4 2013
.UPDATE...
SCATTERED/NUMEROUS SHOWERS WERE LIFTING NORTH ACROSS MAINLY
CENTRAL AND NORTH CENTRAL SOUTH DAKOTA LATE THIS MORNING.
ALSO...REPORTS IN WESTERN CORSON OF THE RAIN CHANGING OVER TO
SNOW. THE LATEST HRRR RUN SHOWS MORE SHOWERS/THUNDERSTORMS
DEVELOPING THIS AFTERNOON/EARLY EVENING ALONG DRY SLOT LIFTING
NORTHWARD IN THE DEEPENING UPPER LOW PRESSURE AREA. ADDED SNOW OR
RAIN/SNOW TO THE FAR WESTERN COUNTIES THROUGH THE AFTERNOON. THE
OTHER ISSUE IS THE STRONG WINDS ALREADY OCCURRING. THE LATEST
MODEL RUNS AND GUIDANCE SHOW THESE STRONG WINDS CONTINUING THROUGH
THE AFTERNOON AND NIGHT. WINDS MAY BE CLOSE TO HIGH WINDS AT TIMES.
WILL LEAVE WIND ADVISORY GOING THROUGH THE NIGHT AND MAY HAVE TO
EXTEND THIS EVEN THROUGH SATURDAY. NOT MUCH CHANGE IN TEMPERATURES
THROUGH THE AFTERNOON WITH CLOUD COVER AND PRECIPITATION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
HEADLINES OVER THE NEXT 24 TO 30 HOURS WILL BE THE MAIN FORECAST
CHALLENGE.
MODELS ARE IN A REASONABLE AGREEMENT THIS MORNING WITH THE
HANDLING OF THE FIRST SNOWSTORM OF THE SEASON. ISENTROPIC UPGLIDE
IS CURRENTLY ONGOING OVER WESTERN SOUTH DAKOTA WHERE WIDESPREAD
LIGHT TO MODERATE RAIN IS OCCURRING. SO FAR ONLY THE HIGHER
TERRAIN AREAS OF THE BLACK HILLS AND EASTERN WYOMING HAS
TRANSITIONED OVER TO ALL SNOW. WITH LIMITED CAA...WAA AT H7...NOT
TOO SURPRISED TO SEE A SLOW TRANSITION OVER TO SNOW. THE 0Z MODEL
RUNS OF THE GFS/NAM/HI-RES ARW ALL SUGGEST LITTLE TO NO SNOW FOR
LOCATIONS ALONG AND EAST OF THE MISSOURI RIVER FOR THIS EVENT. A
FEW MODELS ACTUALLY SHOW KPIR CHANGING OVER TO SNOW SEVERAL HOURS
BEFORE KMBG DOES DUE TO THE PLACEMENT OF THE H5 LOW PRESSURE.
THERE WILL DEFINITELY BE A FINE LINE BETWEEN SIGNIFICANT SNOW
ACCUMULATIONS AND NO SNOWFALL. WITH THE CENTRAL AND WESTERN
PORTIONS OF CORSON AND DEWEY COUNTY SEEING A MORE PROLONGED TIME
PERIOD OF SNOW...HAVE UPGRADED THESE COUNTIES TO A WINTER STORM
WARNING. SINCE SNOW WILL BE DELAYED ELSEWHERE...WILL PUSH THE
WINTER STORM WATCH BACK UNTIL 0Z.
FURTHER EAST...MODELS HAVE DEVELOPED A NOTICEABLE DRY SLOT MOVING
ACROSS THE EASTERN CWA AFTER 6Z SATURDAY. THE CONSENSUS AMONG
MODELS WITH REGARDS TO QPF IS DRASTICALLY LOWER THAN THE PREVIOUS
FORECAST. MODEL SOUNDINGS ARE MORE SUPPORTIVE OF CONTINUOUS DRIZZLE
THAN MODERATE RAINFALL. HAVE LEFT OUT THE MENTION OF DRIZZLE FOR
NOW HOWEVER.
IT HAS BEEN NOTED FOR A WHILE NOW THAT IS STORM SYSTEM WILL BRING
VERY STRONG NORTHERLY WINDS WITH GUSTS AROUND 50 MPH POSSIBLE. THE
PREVIOUS FORECAST SHIFT HAD ALREADY ISSUED A WIND ADVISORY WHICH
LOOKS REALLY GOOD. BASED ON THE GFS LAMP GUIDANCE...HAVE DECIDED
TO ADD BROWN COUNTY INTO THE ADVISORY...AND HAVE EXTENDED THE
ADVISORY IN TIME UNTIL 12Z SATURDAY. CONDITIONS SHOULD GRADUALLY
IMPROVE DURING THE AFTERNOON HOURS ON SATURDAY FROM WEST TO EAST.
.LONG TERM...SUNDAY THROUGH FRIDAY
A QUIET PERIOD EXPECTED AFTER THE LOW CURRENTLY AFFECTING THE
PLAINS EXITS THIS CWA SUNDAY MORNING. UPPER RIDGING AND A SURFACE
BASED LEE SIDE TROUGH WILL MOVE IN FROM THE WEST ON MONDAY AND
TEMPERATURES WILL REBOUND NICELY WITH EXPECTED HIGHS IN THE 60S
THROUGH THE WEEK. WEAK SFC LOW PRESSURE WILL SPREAD OVER THE
REGION BY WED BUT WILL BE MOISTURE STARVED INITIALLY. AS ANOTHER
UPPER TROF MOVES IN THU NIGHT/FRIDAY AND A WELL STACKED LOW
DEVELOPS OVER THE PLAINS PRECIP CHANCES INCREASE.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
RAIN IS EXPECTED TO CONTINUE TO SPREAD ACROSS THE REMAINDER OF
THE REGION TODAY. CURRENT CIGS AND VSBYS REMAIN IN THE VFR TO MVFR
CATEGORIES...WITH THE EXCEPTION OF KATY WHERE A 300 FT STRATUS
DECK IS ALREADY IN PLACE. CIGS ARE EXPECTED TO FALL TO IFR AT ALL
SITES AS HEAVIER PRECIP MOVES IN. NORTHERLY WINDS WILL INCREASE
TODAY TO 25 TO 35 KTS WITH HIGHER GUSTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SATURDAY FOR BROWN-
BUFFALO-CAMPBELL-CORSON-DEWEY-EDMUNDS-FAULK-HAND-HUGHES-
HYDE-JONES-LYMAN-MCPHERSON-POTTER-STANLEY-SULLY-WALWORTH.
WINTER STORM WATCH FROM 7 PM CDT /6 PM MDT/ THIS EVENING THROUGH
SATURDAY AFTERNOON FOR CAMPBELL-HUGHES-JONES-POTTER-STANLEY-
SULLY-WALWORTH.
WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR CORSON-DEWEY.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...WISE
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1024 PM CDT THU OCT 3 2013
.UPDATE...
ISSUED AT 947 PM CDT THU OCT 3 2013
SEVERAL UPDATES TO ACCOUNT FOR PRECIPITATION TREND THIS EVENING
/MAINLY DOWN IN COVERAGE FOR THE SHORTEST TERM/ AND TEMPERATURES.
SURFACE BOUNDARY REMAINS LOCKED JUST SOUTH OF INTERSTATE 80 AT MID
EVENING. COOL NORTH TO NORTHEAST FLOW ACROSS THE AREA...WITH SOME
TEMPS ALREADY BELOW FORECAST LOWS BY 00Z. THE GOOD NEWS IS THAT
TEMPS ARE NOT LIKELY TO MAKE ANY SIGNIFICANT CHANGES OVERNIGHT
WITH BLANKET OF STRATUS AND DEVELOPING/EXPANDING FOG IN SW MN...
SO ONLY MINOR LOWERING OF TEMPS APPEARED TO BE NEEDED IN THE
SOUTHEAST HALF OF THE AREA.
IN TERMS OF PRECIPITATION...EARLIER CONVECTIVE CLUSTER MOVED
QUICKLY AWAY WITH RESIDUAL BOUNDARY OF SOME MID CLOUDS ON TOP OF
STRATUS LAYER CLOSE TO THE MISSOURI VALLEY AT LATE AFTERNOON/EARLY
EVENING. WITH GRADUAL NORTHWARD SHIFT TO 300/305K ISENTROPIC LIFT
AND 850-700 HPA...HAVE SEEN SOME RESURGENCE OF SHOWERS/ISOLATED
THUNDER THROUGH THE MISSOURI VALLEY EARLY THIS EVENING...BUT A
MUCH STRONGER DEVELOPMENT TOWARD THE SURFACE/925 HPA BOUNDARY
ACROSS SOUTHEAST NEBRASKA. HRRR IS PERHAPS CATCHING ON A BIT
BETTER TO OVERALL TRENDS FOR THE NIGHT...BY INDICATING THE MORE
SIGNIFICANT DEVELOPMENT TO THE SOUTH NEAR THE SURFACE/925 HPA
BOUNDARY...BUT TENDENCY FOR MORE ELEVATED ACTIVITY TO SPREAD
NORTHEAST TOWARD KSUX AREA AFTER 06Z... ALONG WITH INCREASE IN THE
850-700 HPA THETA E ADVECTION. PLENTY OF ELEVATED INSTABILITY ON
THE KOAX 00Z SOUNDING...AND EFFECTIVE SHEAR ENOUGH TO THINK THAT
AN ISOLATED STORM MAY PRODUCE A LITTLE MARGINALLY LARGE HAIL LATE
NIGHT...MAINLY SOUTH OF U.S. HIGHWAY 18 IN NW IA...AND FAR SE SD.
OTHER CONVECTION WILL GRADUALLY FILL AND LIFT NORTHEAST.
STILL LOOKING TO BE QUITE A VOLATILE SETUP FOR TOMORROW AFTERNOON
AND EVENING ACROSS NORTHWEST IOWA AND INTO ADJACENT SE SD AND SW
MN. WILL BE PAYING GREAT ATTENTION TO BOUNDARY LOCATIONS...WHICH
IN THE END WILL DEFINE THE GREATEST TORNADIC THREAT ACROSS THE
AREA. SYNTHESIZING NEW DATA...GREATEST THREAT WOULD APPEAR TO BE
GENERALLY ALONG/EAST OF HIGHWAY 60. THOSE WITH OUTDOOR ACTIVITIES
ANYTIME IN THE LATER AFTERNOON/EVENING SHOULD MAKE SURE TO KEEP
VERY WEATHER AWARE GIVEN THE ELEVATED SEVERE WEATHER POTENTIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 410 PM CDT THU OCT 3 2013
MODEL SOLUTIONS AND CONSISTENCY STILL HIGHLY IN QUESTION BOTH TODAY
AND TOMORROW. MAIN CONCERNS GOING INTO TONIGHT ARE THE FACT THAT
NONE OF THE MODELS...INCLUDING THE HIGH RESOLUTION MODELS...HAS ANY
CLUE THAT THE AREA OF SHOWERS AND THUNDERSTORMS IN THE CWA EXISTS.
THIS OF COURSE CREATES PROBLEMS TRYING TO UTILIZE THE MODELS AND
WHERE THEY THINKING PRECIPITATION WILL DEVELOP THIS EVENING. THE
ACTIVITY THAT IS ONGOING DEVELOPED SOMEWHERE NEAR THE 850MB THETA E
ADVECTION THIS MORNING AND HAS CONTINUED THROUGH THE DAY. THE 850MB
TO 750MB LAYER THETA E ADVECTION INCREASES THROUGH THE NIGHT AND
WITH SUPPORTIVE...ALBEIT NOT STRONG...UPPER LEVEL FORCING EXPECT
SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE NIGHT...POSSIBLY
MERGING INTO A MORE SOLID AREA OF RAIN AND LITTLE THUNDER OVER THE
NORTHERN AND WESTERN CWA LATE TONIGHT AND TOMORROW MORNING.
BY TOMORROW THE MAIN WAVE WILL WORK INTO NEBRASKA AND SOUTH DAKOTA
WITH SURFACE LOW PRESSURE EXPECTED TO MOVE INTO NORTHEAST NEBRASKA
AND SOUTHEAST SOUTH DAKOTA LATE FRIDAY AFTERNOON. VERY WARM AND
HUMID AIR WILL BE ON THE EAST AND SOUTHEAST SIDE OF THIS LOW
PRESSURE WITH A WARM FRONT EXPECTED TO BE IN PLACE OVER PARTS OF
NORTHWEST IOWA TOWARDS INTERSTATE 90 IN SOUTHWEST MINNESOTA.
THUNDERSTORMS SHOULD DEVELOP IN NORTHWEST IOWA AND SOUTHEAST SOUTH
DAKOTA AFTER ABOUT 21Z AS THE COLD FRONT ALOFT SWINGS INTO THE AREA.
IMPRESSIVE DIRECTIONAL AND SPEED SHEAR AND CAPE VALUES LIKELY AT
LEAST 2000 J/KG ANY STORMS THAT DEVELOP WILL HAVE A VERY GOOD CHANCE
OF BECOMING SEVERE. LARGE HAIL...STRONG WINDS AND TORNADOES WILL ALL
BE POSSIBLE. QUITE THE POTENTIAL TEMPERATURES GRADIENT ACROSS THE
AREA WITH MID 80S TOWARDS SUX AND SLB...UPPER 60S AROUND FSD AND 50
TO 55 FROM 9V9 TO HON. THE NORTH AND WEST PARTS OF THE CWA SHOULD
SEE A FAIRLY STEADY RAIN THROUGH THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 410 PM CDT THU OCT 3 2013
MODELS ALL IN DECENT AGREEMENT ON THE EVOLUTION AND TRACK OF THE
SIGNIFICANT LOW PRESSURE AND UPPER LOW EJECTING INTO THE PLAINS
FRIDAY INTO SATURDAY. THE SURFACE LOW WILL TRACK NORTH NORTHEAST
THROUGH EASTERN NEBRASKA INTO INTO FAR SOUTHEAST SOUTH DAKOTA. AS
MENTIONED ABOVE...SEVERE THUNDERSTORMS ARE POSSIBLE IN THE WARM
SECTOR OF THIS SYSTEM ACROSS PORTIONS OF SOUTHWEST MINNESOTA AND
NORTHWEST IOWA. EXPECT THE COLD FRONT TO BE THROUGH THE CWA BY
AROUND 03Z...WITH THE SEVERE THREAT ENDING WITH THAT PASSAGE. EXACT
TIMING AND WARM FRONT POSITIONING WILL LIKELY CHANGE AND NOT BE
KNOWN UNTIL TOMORROW MORNING...SO STAY TUNED TO FUTURE UPDATES. WITH
THE FURTHER NORTH TRACK OF THE UPPER LOW...LOOKS LIKE THE DRY SLOT
WILL MOVE INTO AT LEAST THE SOUTHEAST HALF OF OUR CWA FOR MUCH OF
FRIDAY NIGHT. RAIN SHOULD CONTINUE NORTHWEST OF A LINE FROM
BROOKINGS TO LAKE ANDES ON THE COOL SIDE OF THE LOW PRESSURE IN AN
AREA OF STRONG DYNAMICAL FORCING. QUESTION THEN BECOMES DO WE SEE A
CHANGEOVER TO SNOW AT ALL IN OUR WEST. IT WILL BE A CLOSE CALL IN
OUR FAR WEST...ALTHOUGH IT LOOKS LIKE MOST OF THE SNOW WILL REMAIN
WEST OF THE CWA. DO THINK WE COULD SEE SNOW MIX IN ACROSS BRULE AND
GREGORY COUNTIES AFTER MIDNIGHT INTO SATURDAY MORNING. HOWEVER
TEMPERATURES ALOFT AND AT THE SURFACE APPEAR VERY MARGINAL EVEN
THERE...AND CURRENTLY THINK WE MAY SEE UP TO AN INCH...BUT NOT MORE.
THE 12Z NAM WAS MOST AGGRESSIVE WITH THE SNOW...BUT THE 18Z NAM
BACKED OFF SOME...AND THE 15Z SREF ONLY HAS ABOUT A 30 TO 40 PERCENT
CHANCE OF OVER AN INCH. SO FEEL COMFORTABLE WITH NOT GOING ANY
HIGHER WITH SNOW TOTALS...BUT MODEL TRENDS WILL HAVE TO BE WATCHED
CLOSELY...AS THERE WILL LIKELY BE A TIGHT GRADIENT OF ACCUMULATIONS
NOT TOO FAR FROM OUR CWA BORDER. MAY SEE SOME LINGERING RAIN SHOWERS
THROUGH THE AFTERNOON ON SATURDAY. WINDS WILL BE QUITE STRONG OUT OF
THE NORTHWEST FRIDAY NIGHT INTO SATURDAY ON THE BACKSIDE OF THE LOW.
STILL SOME UNCERTAINTY ON HOW FAST THE LOW PUSHES EAST...WHICH WILL
DETERMINE HOW QUICKLY THE WINDS PICK UP. MODELS HAVE BEEN ALL OVER
THE PLACE WITH REGARD TO WHETHER THE LOW KICKS EAST PRETTY QUICKLY
SATURDAY...OR LINGERS OVERHEAD. THE GOING FORECAST USED SOMETHING
CLOSE TO A 12Z MODEL CONSENSUS...RESULTING IN POTENTIAL WIND
ADVISORY CRITERIA ALONG THE MISSOURI RIVER AND WEST OF THE JAMES
RIVER...APPROACHING THE INTERSTATE 29 CORRIDOR. HIGHS ON SATURDAY
LIKELY ONLY IN THE 40S TO LOW 50S...WHICH COMBINED WITH THE WIND AND
SHOWERS WILL MAKE FOR A COLD AND RAW DAY.
LOWS SATURDAY NIGHT TRICKY AS WELL. IF THE UPPER LOW KICKS OUT
QUICKLY...WE COULD SEE SOME DECENT RADIATIONAL COOLING...WHICH WOULD
BEING A FROST OR FREEZE BACK INTO PLAY. WHILE IF THE LOW LINGERS
LIKE THE EC AND 18Z NAM SOLUTIONS...TEMPERATURES WOULD STAY IN THE
MID TO UPPER 30S WITH EVEN A FEW RAIN SHOWERS POSSIBLE. WOULD EXPECT
CLEARING SKIES THROUGH THE DAY ON SUNDAY...WITH HIGHS IN THE 50S.
UPPER LEVEL RIDGING BUILDS IN MONDAY INTO MID WEEK...WITH PARTLY TO
MOSTLY SUNNY SKIES AND WARMING TEMPERATURES. SHOULD BE A NICE FEW
DAYS...WITH HIGHS IN THE 60S AND 70S FROM MONDAY RIGHT INTO
THURSDAY. THE NEXT BATCH OF ENERGY MOVING INTO THE WEST COAST IS NOW
PROGGED TO DIVE INTO THE SOUTHWESTERN PORTION OF THE COUNTRY...WHICH
SHOULD DELAY ITS ARRIVAL INTO OUR CWA UNTIL AT LEAST THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 1024 PM CDT THU OCT 3 2013
AVIATION CONCERNS ARE PROLIFIC OVER THE NEXT 24 HOURS. WIDESPREAD
IFR AND LOWER CEILINGS AND VISIBILITIES WILL BLANKET ALL SITES
THROUGH THE NIGHT AND INTO AT LEAST MID MORNING HOURS...THEN WORK
AT ADVECTING OUT OF SIOUX CITY WHILE HEATING MORE TOWARD MVFR
CEILINGS AND EVENTUALLY BREAKING OUT OF CLOUDINESS FOR A TIME
AROUND KSUX BY EARLY TO MID AFTERNOON. THE LOWER VISIBILITIES WILL
CONTINUE TO EXPAND SOUTH AND WEST OUT OF SW MN...WITH A CONTINUED
THREAT FOR A FEW AREAS OF DRIZZLE AS WELL WHERE MOISTURE REMAINS
SHALLOW.
FINALLY...MOST SIGNIFICANT WILL BE THE THREAT FOR SEVERE STORMS
AROUND THE KFSD AND KSUX TAF SITES LATE AFTERNOON AND EARLY
EVENING. VERY LARGE HAIL...DAMAGING WIND...AND A FEW TORNADOES
WILL BE POSSIBLE WITH LATE DAY STORM RAPID EVOLUTION.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
947 PM CDT THU OCT 3 2013
.UPDATE...
ISSUED AT 947 PM CDT THU OCT 3 2013
SEVERAL UPDATES TO ACCOUNT FOR PRECIPITATION TREND THIS EVENING
/MAINLY DOWN IN COVERAGE FOR THE SHORTEST TERM/ AND TEMPERATURES.
SURFACE BOUNDARY REMAINS LOCKED JUST SOUTH OF INTERSTATE 80 AT MID
EVENING. COOL NORTH TO NORTHEAST FLOW ACROSS THE AREA...WITH SOME
TEMPS ALREADY BELOW FORECAST LOWS BY 00Z. THE GOOD NEWS IS THAT
TEMPS ARE NOT LIKELY TO MAKE ANY SIGNIFICANT CHANGES OVERNIGHT
WITH BLANKET OF STRATUS AND DEVELOPING/EXPANDING FOG IN SW MN...
SO ONLY MINOR LOWERING OF TEMPS APPEARED TO BE NEEDED IN THE
SOUTHEAST HALF OF THE AREA.
IN TERMS OF PRECIPITATION...EARLIER CONVECTIVE CLUSTER MOVED
QUICKLY AWAY WITH RESIDUAL BOUNDARY OF SOME MID CLOUDS ON TOP OF
STRATUS LAYER CLOSE TO THE MISSOURI VALLEY AT LATE AFTERNOON/EARLY
EVENING. WITH GRADUAL NORTHWARD SHIFT TO 300/305K ISENTROPIC LIFT
AND 850-700 HPA...HAVE SEEN SOME RESURGENCE OF SHOWERS/ISOLATED
THUNDER THROUGH THE MISSOURI VALLEY EARLY THIS EVENING...BUT A
MUCH STRONGER DEVELOPMENT TOWARD THE SURFACE/925 HPA BOUNDARY
ACROSS SOUTHEAST NEBRASKA. HRRR IS PERHAPS CATCHING ON A BIT
BETTER TO OVERALL TRENDS FOR THE NIGHT...BY INDICATING THE MORE
SIGNIFICANT DEVELOPMENT TO THE SOUTH NEAR THE SURFACE/925 HPA
BOUNDARY...BUT TENDENCY FOR MORE ELEVATED ACTIVITY TO SPREAD
NORTHEAST TOWARD KSUX AREA AFTER 06Z... ALONG WITH INCREASE IN THE
850-700 HPA THETA E ADVECTION. PLENTY OF ELEVATED INSTABILITY ON
THE KOAX 00Z SOUNDING...AND EFFECTIVE SHEAR ENOUGH TO THINK THAT
AN ISOLATED STORM MAY PRODUCE A LITTLE MARGINALLY LARGE HAIL LATE
NIGHT...MAINLY SOUTH OF U.S. HIGHWAY 18 IN NW IA...AND FAR SE SD.
OTHER CONVECTION WILL GRADUALLY FILL AND LIFT NORTHEAST.
STILL LOOKING TO BE QUITE A VOLATILE SETUP FOR TOMORROW AFTERNOON
AND EVENING ACROSS NORTHWEST IOWA AND INTO ADJACENT SE SD AND SW
MN. WILL BE PAYING GREAT ATTENTION TO BOUNDARY LOCATIONS...WHICH
IN THE END WILL DEFINE THE GREATEST TORNADIC THREAT ACROSS THE
AREA. SYNTHESIZING NEW DATA...GREATEST THREAT WOULD APPEAR TO BE
GENERALLY ALONG/EAST OF HIGHWAY 60. THOSE WITH OUTDOOR ACTIVITIES
ANYTIME IN THE LATER AFTERNOON/EVENING SHOULD MAKE SURE TO KEEP
VERY WEATHER AWARE GIVEN THE ELEVATED SEVERE WEATHER POTENTIAL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 410 PM CDT THU OCT 3 2013
MODEL SOLUTIONS AND CONSISTENCY STILL HIGHLY IN QUESTION BOTH TODAY
AND TOMORROW. MAIN CONCERNS GOING INTO TONIGHT ARE THE FACT THAT
NONE OF THE MODELS...INCLUDING THE HIGH RESOLUTION MODELS...HAS ANY
CLUE THAT THE AREA OF SHOWERS AND THUNDERSTORMS IN THE CWA EXISTS.
THIS OF COURSE CREATES PROBLEMS TRYING TO UTILIZE THE MODELS AND
WHERE THEY THINKING PRECIPITATION WILL DEVELOP THIS EVENING. THE
ACTIVITY THAT IS ONGOING DEVELOPED SOMEWHERE NEAR THE 850MB THETA E
ADVECTION THIS MORNING AND HAS CONTINUED THROUGH THE DAY. THE 850MB
TO 750MB LAYER THETA E ADVECTION INCREASES THROUGH THE NIGHT AND
WITH SUPPORTIVE...ALBEIT NOT STRONG...UPPER LEVEL FORCING EXPECT
SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE NIGHT...POSSIBLY
MERGING INTO A MORE SOLID AREA OF RAIN AND LITTLE THUNDER OVER THE
NORTHERN AND WESTERN CWA LATE TONIGHT AND TOMORROW MORNING.
BY TOMORROW THE MAIN WAVE WILL WORK INTO NEBRASKA AND SOUTH DAKOTA
WITH SURFACE LOW PRESSURE EXPECTED TO MOVE INTO NORTHEAST NEBRASKA
AND SOUTHEAST SOUTH DAKOTA LATE FRIDAY AFTERNOON. VERY WARM AND
HUMID AIR WILL BE ON THE EAST AND SOUTHEAST SIDE OF THIS LOW
PRESSURE WITH A WARM FRONT EXPECTED TO BE IN PLACE OVER PARTS OF
NORTHWEST IOWA TOWARDS INTERSTATE 90 IN SOUTHWEST MINNESOTA.
THUNDERSTORMS SHOULD DEVELOP IN NORTHWEST IOWA AND SOUTHEAST SOUTH
DAKOTA AFTER ABOUT 21Z AS THE COLD FRONT ALOFT SWINGS INTO THE AREA.
IMPRESSIVE DIRECTIONAL AND SPEED SHEAR AND CAPE VALUES LIKELY AT
LEAST 2000 J/KG ANY STORMS THAT DEVELOP WILL HAVE A VERY GOOD CHANCE
OF BECOMING SEVERE. LARGE HAIL...STRONG WINDS AND TORNADOES WILL ALL
BE POSSIBLE. QUITE THE POTENTIAL TEMPERATURES GRADIENT ACROSS THE
AREA WITH MID 80S TOWARDS SUX AND SLB...UPPER 60S AROUND FSD AND 50
TO 55 FROM 9V9 TO HON. THE NORTH AND WEST PARTS OF THE CWA SHOULD
SEE A FAIRLY STEADY RAIN THROUGH THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 410 PM CDT THU OCT 3 2013
MODELS ALL IN DECENT AGREEMENT ON THE EVOLUTION AND TRACK OF THE
SIGNIFICANT LOW PRESSURE AND UPPER LOW EJECTING INTO THE PLAINS
FRIDAY INTO SATURDAY. THE SURFACE LOW WILL TRACK NORTH NORTHEAST
THROUGH EASTERN NEBRASKA INTO INTO FAR SOUTHEAST SOUTH DAKOTA. AS
MENTIONED ABOVE...SEVERE THUNDERSTORMS ARE POSSIBLE IN THE WARM
SECTOR OF THIS SYSTEM ACROSS PORTIONS OF SOUTHWEST MINNESOTA AND
NORTHWEST IOWA. EXPECT THE COLD FRONT TO BE THROUGH THE CWA BY
AROUND 03Z...WITH THE SEVERE THREAT ENDING WITH THAT PASSAGE. EXACT
TIMING AND WARM FRONT POSITIONING WILL LIKELY CHANGE AND NOT BE
KNOWN UNTIL TOMORROW MORNING...SO STAY TUNED TO FUTURE UPDATES. WITH
THE FURTHER NORTH TRACK OF THE UPPER LOW...LOOKS LIKE THE DRY SLOT
WILL MOVE INTO AT LEAST THE SOUTHEAST HALF OF OUR CWA FOR MUCH OF
FRIDAY NIGHT. RAIN SHOULD CONTINUE NORTHWEST OF A LINE FROM
BROOKINGS TO LAKE ANDES ON THE COOL SIDE OF THE LOW PRESSURE IN AN
AREA OF STRONG DYNAMICAL FORCING. QUESTION THEN BECOMES DO WE SEE A
CHANGEOVER TO SNOW AT ALL IN OUR WEST. IT WILL BE A CLOSE CALL IN
OUR FAR WEST...ALTHOUGH IT LOOKS LIKE MOST OF THE SNOW WILL REMAIN
WEST OF THE CWA. DO THINK WE COULD SEE SNOW MIX IN ACROSS BRULE AND
GREGORY COUNTIES AFTER MIDNIGHT INTO SATURDAY MORNING. HOWEVER
TEMPERATURES ALOFT AND AT THE SURFACE APPEAR VERY MARGINAL EVEN
THERE...AND CURRENTLY THINK WE MAY SEE UP TO AN INCH...BUT NOT MORE.
THE 12Z NAM WAS MOST AGGRESSIVE WITH THE SNOW...BUT THE 18Z NAM
BACKED OFF SOME...AND THE 15Z SREF ONLY HAS ABOUT A 30 TO 40 PERCENT
CHANCE OF OVER AN INCH. SO FEEL COMFORTABLE WITH NOT GOING ANY
HIGHER WITH SNOW TOTALS...BUT MODEL TRENDS WILL HAVE TO BE WATCHED
CLOSELY...AS THERE WILL LIKELY BE A TIGHT GRADIENT OF ACCUMULATIONS
NOT TOO FAR FROM OUR CWA BORDER. MAY SEE SOME LINGERING RAIN SHOWERS
THROUGH THE AFTERNOON ON SATURDAY. WINDS WILL BE QUITE STRONG OUT OF
THE NORTHWEST FRIDAY NIGHT INTO SATURDAY ON THE BACKSIDE OF THE LOW.
STILL SOME UNCERTAINTY ON HOW FAST THE LOW PUSHES EAST...WHICH WILL
DETERMINE HOW QUICKLY THE WINDS PICK UP. MODELS HAVE BEEN ALL OVER
THE PLACE WITH REGARD TO WHETHER THE LOW KICKS EAST PRETTY QUICKLY
SATURDAY...OR LINGERS OVERHEAD. THE GOING FORECAST USED SOMETHING
CLOSE TO A 12Z MODEL CONSENSUS...RESULTING IN POTENTIAL WIND
ADVISORY CRITERIA ALONG THE MISSOURI RIVER AND WEST OF THE JAMES
RIVER...APPROACHING THE INTERSTATE 29 CORRIDOR. HIGHS ON SATURDAY
LIKELY ONLY IN THE 40S TO LOW 50S...WHICH COMBINED WITH THE WIND AND
SHOWERS WILL MAKE FOR A COLD AND RAW DAY.
LOWS SATURDAY NIGHT TRICKY AS WELL. IF THE UPPER LOW KICKS OUT
QUICKLY...WE COULD SEE SOME DECENT RADIATIONAL COOLING...WHICH WOULD
BEING A FROST OR FREEZE BACK INTO PLAY. WHILE IF THE LOW LINGERS
LIKE THE EC AND 18Z NAM SOLUTIONS...TEMPERATURES WOULD STAY IN THE
MID TO UPPER 30S WITH EVEN A FEW RAIN SHOWERS POSSIBLE. WOULD EXPECT
CLEARING SKIES THROUGH THE DAY ON SUNDAY...WITH HIGHS IN THE 50S.
UPPER LEVEL RIDGING BUILDS IN MONDAY INTO MID WEEK...WITH PARTLY TO
MOSTLY SUNNY SKIES AND WARMING TEMPERATURES. SHOULD BE A NICE FEW
DAYS...WITH HIGHS IN THE 60S AND 70S FROM MONDAY RIGHT INTO
THURSDAY. THE NEXT BATCH OF ENERGY MOVING INTO THE WEST COAST IS NOW
PROGGED TO DIVE INTO THE SOUTHWESTERN PORTION OF THE COUNTRY...WHICH
SHOULD DELAY ITS ARRIVAL INTO OUR CWA UNTIL AT LEAST THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 701 PM CDT THU OCT 3 2013
COMPLEX AVIATION FORECAST FOR THE NEXT 24 HOURS. LOW LEVEL
BOUNDARY DOWN AROUND INTERSTATE 80...WITH WIDESPREAD IFR CEILINGS
ALONG AND NORTH OF A KEST TO KONL LINE. EXPECT THESE TO BECOME
MORE PREVALENT AND LOWER SOME OVERNIGHT...LIKELY WITH SOME
VISIBILITIES ALSO DROPPING TO IFR OR BRIEFLY LOWER. PRECIPITATION
IS VERY DIFFICULT TO TIME...BUT OTHER THAN SMALL BAND THIS EVENING
ALONG THE 700 HPA THETA E ADVECTION AXIS TO THE SOUTH...MAY BE
GOING MORE TO DEVELOPING A LITTLE MORE WIDESPREAD SHALLOW DRIZZLE
TYPE FOR SEVERAL HOURS OVERNIGHT. THERE CONTINUES TO BE INDICATIONS
OF PERSISTENT ISENTROPIC LIFT WHICH SEEMS TO BECOME MORE FOCUSED
AND STRENGTHENS OVERNIGHT ON THE NOSE OF APPROACHING MID LEVEL
DRYING...WHICH SHOULD RESULT IN INCREASE IN SHOWER/THUNDER
COVERAGE LATER IN THE NIGHT. ALSO...HAVE TO WATCH THE SMALLER
CONVECTIVE LOOKING CELLS ON TOP OF THE STRATUS LAYER PER LAST LOOK
AT VISIBLE SATELLITE PICTURE FOR ANY ADDITIONAL ORGANIZED
DEVELOPMENT.
OTHER SIGNIFICANT CONCERN FOR AVIATION IS THE SEVERE WEATHER
THREAT. THERE IS SOME DECENT ELEVATED INSTABILITY WHICH SPREADS IN
WITH DRY SLOT NOSE LATE TONIGHT...AND MAY FIND A COUPLE OF LARGER
HAIL PRODUCING STORMS LATER IN THE OVERNIGHT TOWARD KSUX.
OTHERWISE...AWARENESS OF THE POTENTIAL SEVERE WEATHER OUTBREAK FOR
KFSD/KSUX AND EASTWARD FOR LATER FRIDAY AFTERNOON AND EVENING IN
ORDER...WITH THREAT FOR LARGER HAIL...DAMAGING WIND...AND ISOLATED
TORNADOES WITH EXPLOSIVE CONVECTIVE DEVELOPMENT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1027 AM CDT FRI OCT 4 2013
.UPDATE...(SEVERE WEATHER RISK TODAY/TONIGHT)
ISSUED AT 1027 AM CDT FRI OCT 4 2013
SETUP FOR LATER TODAY EVEN MORE MUDDLED WITH MAIN WARM FRONT SO FAR
SOUTH AT MOMENT. TRENDS IN MESOSCALE GUIDANCE AND OBSERVATIONS
SUGGEST...AS PREVIOUS FORECASTERS POINTED OUT...THAT HIGH RISK OF
SEVERE WEATHER APPEARS TO BE SHIFTING WEST AND SOUTH. STORM
PREDICTION CENTER GUIDANCE ALSO TRENDING THAT WAY AND WILL BE
INTERESTING TO SEE WHAT LATER UPDATES PROGRESS TO.
ALONG AND NORTH OF INTERSTATE 90...COOL FLOW NORTH OF BOUNDARY SEEMS
TO BE WELL ESTABLISHED AND REINFORCING LOW CLOUDS AND FOG. FLOW MORE
DISCRETE ACROSS IOWA INTO SOUTHERN WISCONSIN BEHIND EXITING
MESOSCALE CONVECTIVE SYSTEM...WITH MAIN OUTFLOW NEARLY TO THE
MISSOURI BORDER AT MOMENT. YOU HAVE TO GO TO SOUTHWEST IOWA TO FIND
BREAKS IN CLOUDS BUT LOTS OF CLOUD DEBRIS UPSTREAM THAT MAY DAMPEN
THREATS OF WARM SECTOR ADVANCING NORTH. DYNAMICS OF APPROACHING WAVE
WILL CERTAINLY PROVIDE PUSH NORTH BUT THIS MIGHT MATERIALIZE AS
WIDESPREAD CONVECTIVE DEVELOPMENT. WINDOW FOR STRONGER SUPERCELLS
AND RELATED HIGHER SEVERE WEATHER RISK MAY BE NARROW AND AGAIN...
FURTHER WEST OR SOUTHWEST OF AREA. WIDESPREAD SHOWER ACTIVITY WILL
LIKELY HAVE EMBEDDED...FAST MOVING ELEVATED THUNDERSTORMS FROM LATE
AFTERNOON INTO EVENING...WITH THREAT OF STRONGER TO SEVERE STORMS
MOVING IN LATER IN EVENING IN DIMINISHING STATE.
ALL IN ALL...LOTS OF UNCERTAINTIES BUT THREAT FOR ROUNDS OF HEAVY
RAIN AND LIGHTNING STILL THERE. WILL CONTINUE TO MONITOR SEVERE
WEATHER TRENDS AND IF NEEDED...TRANSITION PRODUCT SUITE TO LESS OF A
RISK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI OCT 4 2013
MOST OF THE FORECAST WAS SPENT ON TRYING TO IMPROVE THE FORECAST
TODAY THROUGH SATURDAY AND EVALUATING THE SEVERE WEATHER RISK. IT
LOOKS LIKE THERE IS A RISK...BUT THE THREAT HAS DIMINISHED
SOMEWHAT AND SHIFTED WEST.
SURFACE ANALYSIS SHOWING COMPLEX YET FAIRLY ORGANIZED AIR MASS
FRONTAL BOUNDARIES THIS MORNING. STALLED SURFACE BOUNDARY
ORIENTED SW-NE ACROSS NE IA AND SWRN WI WITH SOME CAPE ALONG AND
TO ITS SOUTH. MORE OF THE MARITIME TROPICAL AIR IS LOCATED SOUTH
OF A WARM-STATIONARY FRONT IN THE VICINITY OF THE IA-MO
BORDER...FEEDING WITH MUCH OF THE NOCTURNAL CONVECTION IN IA. MAIN
SYNOPTIC SURFACE LOW ASSOCIATED WITH THE STRONG-DEEP TROPOSPHERIC
SYSTEM OVER UTAH IS STILL LOCATED BACK IN WRN KS. WEAK PRESSURE
FALLS OF 1MB/3HR CENTERED OVER NEBRASKA SUGGEST THE LOW CENTER
SHOULD EJECT WEST OF OMAHA. 04.00Z NAM HAS THE BEST LOOKING SEA-
LEVEL VERIFICATION AT 06Z.
MID-UPPER LEVEL SYSTEM CENTERED OVER UT PER WATER VAPOR
IMAGERY...WITH SIGNIFICANT POTENTIAL VORTICITY IN THE SRN MOST PART
OF THE STATE WITH A TROP FOLD DOWN TO ABOUT 500MB. HAVE SOME
CONCERNS WITH UPPER JET ENERGY ON NORTHWEST SIDE OF TROUGH WITH
SPOKANE RAOB COMING IN WITH 130 KTS...WHICH 04.00Z GFS INITIALIZED
BEST BUT STILL TOO WEAK...AND 110 KTS IN SRN B.C. NET EFFECT OF
UNDER INITIALIZATION /10-15KTS/ WOULD BE TO HOLD THE MID-UPPER
TROUGH ENERGY BACK IN THE SW U.S. AND EJECT THE SRN UT ENERGY
SLIGHTLY FURTHER WEST THAN CURRENTLY FORECAST. WATER VAPOR ALSO
YIELDING A FOOTPRINT OF A SHORTWAVE TROUGH SW OF OMAHA AT 05Z
ENHANCING CONVECTION SHIFTING NORTHEAST. THIS WILL MOVE THROUGH
THE FORECAST AREA.
FOR THE MOST PART THE LATEST MODEL GUIDANCE PROVIDES SOME CONSENSUS
ON THE NEXT DAYS. BUT THE DETAILS ON TIMING ARE STILL GOING TO BE
DIFFICULT. LOOKING AT THE TRENDS IN THE MODELS...THE 12 HOUR TREND
/12-18-00Z MODEL RUNS/ AT THE SURFACE IS FOR A SLOWER AND FURTHER
SOUTHWEST POSITION TO THE SYNOPTIC FEATURES. THIS FAVORS A SURFACE
LOW IN NERN NEB BY EARLY THIS EVENING...WITH THE SLOWLY NORTHWARD
MOVING WARM FRONT JUST TO OUR SOUTH IN IA /VERSUS I-90/ AND THE
FORECAST AREA IN SE-EASTERLY FLOW...COOLER THERMAL CONDITIONS ALL DAY
FRIDAY NORTH OF THE WARM FRONT. WITH MUCH OF THE CAPE TIED TO THE
WARM SECTOR...AND THE SLOWER TIMING INTO THE OVERNIGHT FOR THE
WARM SECTOR ARRIVAL...THIS SHOULD DECREASE THE SEVERE WEATHER
POTENTIAL ACROSS THE AREA...AT LEAST FOR TORNADOES AND LARGE HAIL
AND DAMAGING WIND COVERAGE. IT APPEARS THE HIGHEST RISK IS FURTHER
WEST/SOUTH THAN YESTERDAYS FORECAST.
THIS MORNINGS SHORTWAVE TROUGH EAST OF KDSM AT 08Z LOOKS TO
CONTINUE NORTHEAST THIS MORNING BRINGING RAIN NORTHWARD. MUCAPE
ANALYSIS INDICATES ABOUT 500 J/KG FROM NE IA TO CENTRAL WI AND
SOUTHEAST. PER THE LATEST WIND PROFILES...THE LOW-LEVEL JET IS
CONVERGENT INTO SRN IA AND PER THE LATEST RAP FORECASTS...THAT THE
STRONGER FORCING REMAINS /SRN IA/ UNTIL LATER WHEN IT STARTS TO
SHIFT NORTH. HOWEVER...THE 04.07Z RAP NOW SUGGESTS A SLIGHT
MOISTURE TRANSPORT SIGNAL MOVES NORTH WITH THE SHORTWAVE INTO
CENTRAL WI. WEAK...BUT MAYBE ENOUGH TO KEEP SOME SHOWERS GOING
INTO CENTRAL WI. HAVE DETAILED THE PRECIPITATION CHANCES FOR TODAY
TO HAVE MINIMUM AROUND MID DAY AFTER MORNING RAINS...ESPECIALLY
IN THE SOUTH.
TODAY WITH BOUNDARY ACROSS THE FORECAST AREA AND THE SOUTHERN WARM
FRONT MERGING TODAY...THERE IS PLENTY OF SOUTHEAST FLOW ACROSS THE
SOUTH MAKING FOR LARGER CURVING HODOGRAPHS BY LATER AFTERNOON.
HOWEVER...THE LOW-LEVEL WIND FIELD IS NOT CONVERGENT EXCEPT ON THE
FRONT FURTHER SOUTH OF THE FORECAST AREA. THE AIR MASS SEEMS TO
HAVE LITTLE CAP INDICATED IN THE FORECAST MODELS IN THE SOUTH
AROUND MID-DAY. THUS...AS THE SYSTEM EJECTS FROM THE ROCKIES AND THE
SOUTHERLY JET INCREASES...WIDESPREAD SHOWERS AND STORMS SHOULD
DEVELOP IN ISENTROPIC LIFT AND A CONVERGENT LOW-LEVEL JET ACROSS
NRN IA BY MID-LATE AFTERNOON. THIS BROAD LIFT AND LACK OF SURFACE
CONVERGENCE IN THE FORECAST AREA SEEMS TO SUGGEST A BROAD AREA OF
COMPETING STORMS WOULD USE THE AVAILABLE CAPE....NOT A SURFACE-
BOUNDARY-FORCED CAP BREAKING EVENT WHICH WOULD FAVOR TORNADOES AND
MORE SEVERE WEATHER. THUS...IT SEEMS EMBEDDED SEVERE STORMS WITH
IN A BROADER HEAVY RAIN PRECIPITATION REGION SHOULD DEVELOP ACROSS
THE SOUTH LATER THIS AFTERNOON. THE FORCING IS BEST WEST OF THE
MISSISSIPPI RIVER.
THE SPC MODERATE RISK HAS NOT EVOLVED WEST...EVEN THOUGH THE
WEATHER SYSTEM SOLUTION HAS...TO FURTHER WEST AND SLOWER. WOULD
THINK THE MODERATE RISK IS WEST OF THE FORECAST AREA. THE BEST
THREAT FOR THE SEVERE STORMS LOOKS TO BE SOUTHWEST OF A DODGE
CENTER MN TO BOSCOBEL WISCONSIN LINE...AND WILL CHANGE FORECAST
PRODUCTS ACCORDINGLY. IT SEEMS THE LACK OF A GOOD SURFACE WARM
FRONTAL BOUNDARY AND CONVERGENCE WILL FAVOR A BROAD CONVECTIVE
MODE RATHER THAN SUPERCELLS...AND THUS A VERY REDUCED TORNADO
THREAT.
TONIGHT MAY PROVIDE A BETTER SEVERE THREAT AS THE COLD FRONT
INITIATED CONVECTIVE LINE FROM WESTERN IA SHIFTS EAST AND ARRIVES
IN THE LATE EVENING. FORCING AND DYNAMICS ARE STRONGER...BUT CAPE
IS REALLY LOWERING IN THAT 03-06Z PERIOD...HOWEVER THE FORECAST
AREA...ESPECIALLY I-90 AND SOUTH...SEEMS TO GET INTO A NARROW WARM
SECTOR REGION. SO...BOWING WIND SEGMENTS OF CONVECTION ARE
WITH WIND DAMAGE POSSIBLE. THIS IS A DIFFICULT FORECAST AS SOME
STORMS/RAIN ARE EXPECTED ASSOCIATED WITH THE WARM FRONT FORCING IN
THE HOURS PRIOR. THUS LATE EVENING AND OVERNIGHT CONVECTION MAY
BE ALL DYNAMICS AND LITTLE CAPE. NORTH OF THE TRIPLE POINT...SERN
MN INTO CENTRAL WI...HEAVY RAIN IN STRONGLY FORCED ISENTROPIC LIFT
SEEMS TO BE A STRONG SIGNAL IN THE MODELS. THERE COULD BE
LOCALIZED FLOODING THREATS THERE...DEPENDING ON RATES. THE SOILS
SHOULD BE ABLE TO HANDLE A FEW INCHES IF IT DOESNT COME AT ONCE.
WILL REISSUE AN ESF/DISCUSSION ON THIS RAIN POTENTIAL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI OCT 4 2013
THE COLD FRONT IS MOVING THROUGH THE FORECAST AREA OVERNIGHT AND
SATURDAY IT WILL BE FOUND IN CENTRAL WI AROUND MID-DAY. STORMS MAY
INITIATE ON THE FRONT...BUT IT WOULD APPEAR THE BETTER SEVERE
RISK WOULD BE EAST OF THE FORECAST AREA. SHOULD THE FRONT
SLOW...INSTABILITY WOULD IN THE LOWER CATEGORY IN HIGH
SHEAR...CAPABLE OF MINI-SUPERCELLS AND HAIL-WIND THREATS.
SUNDAY CONTINUES TO BE COOL IN THE POST-FRONTAL ENVIRONMENT. THERE
STILL APPEARS TO BE SOME TIMING AND INTENSITY DIFFERENCES WITH THE
DEFORMATION BAND OF PRECIPITATION BEHIND THE DEPARTING LOW. HAVE
DECIDED TO INCREASE PRECIPITATION CHANCES SUNDAY ESPECIALLY FURTHER
NORTHWEST.
MONDAY THROUGH THURSDAY...ANOTHER PERIOD OF ABOVE NORMAL FALL DAYS
WITH A GOOD AMOUNT OF SUNSHINE AS LONG WAVE RIDGING AGAIN BUILDS
IN. MODEL AGREEMENT AND CONFIDENCE IS HIGH FOR THIS PERIOD AS THE
LONG WAVE TROUGH DIGS OVER THE SOUTHWEST U.S. WEATHER SHOULD
BECOME MORE ACTIVE FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI OCT 4 2013
ABUNDANT LOW LEVEL MOISTURE OVER THE AREA COMBINED WITH INCREASING
LIFT AHEAD OF A STRONG MID LEVEL TROUGH AND APPROACHING SFC LOW
LOOKS TO PRODUCE AN EXTENDED PERIOD OF IFR/MVFR FOR THE AREA TODAY
THRU SAT. A FRONTAL BOUNDARY PUSHED SOUTH OF THE AREA LATE THU...AND
APPEARS AS THOUGH IT WILL STAY SOUTH OF THE AREA THRU TONIGHT. IF
THE FRONT DOES STAY SOUTH OF THE AREA...THIS WILL LIMIT THE
POTENTIAL OF SEVERE STORMS THIS AFTERNOON/EVENING. NORTH OF THIS
BOUNDARY...LOW STRATUS AND BR/FG WILL PREVAIL MUCH OF TODAY/
TONIGHT. INCREASING LIFT AHEAD OF THE APPROACHING SYSTEM WILL SEND
ROUNDS OF SHRA/TSRA ACROSS THE TAF SITES TODAY/TONIGHT. ONE OF THESE
WILL MOVE ACROSS THE AREA THIS MORNING...WITH ANOTHER ROUND EXPECTED
TO DEVELOP NORTH OF THE FRONTAL BOUNDARY ACROSS CENTRAL IA AND MOVE
ACROSS THE AREA THIS AFTERNOON/EVENING. YET ANOTHER ROUND LATER
TONIGHT AS THE SFC LOW MOVES INTO MN AND THE COLD FRONT APPROACHES.
GIVEN PLENTY OF DETAIL AND TIMING UNCERTAINTIES BEYOND THIS
MORNING...GENERALLY CARRIED VCSH/VCTS IN THE TAFS VS. LONGER PERIODS
OF SHRA/TSRA. BR/LOW STRATUS WILL GENERALLY KEEP FLIGHT CATEGORIES
IFR/MVFR WITH OR WITHOUT SHRA/TSRA...THOUGH SHRA/TSRA PASSING THU
MAY ACTUALLY RAISE THE CIGS/VSBYS. LATER TAF CYCLES OR UPDATES CAN
ADD MORE SHRA/TSRA WHEN TIMING DETAILS BECOME CLEARER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT FRI OCT 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI OCT 4 2013
MOST OF THE FORECAST WAS SPENT ON TRYING TO IMPROVE THE FORECAST
TODAY THROUGH SATURDAY AND EVALUATING THE SEVERE WEATHER RISK. IT
LOOKS LIKE THERE IS A RISK...BUT THE THREAT HAS DIMINISHED
SOMEWHAT AND SHIFTED WEST.
SURFACE ANALYSIS SHOWING COMPLEX YET FAIRLY ORGANIZED AIR MASS
FRONTAL BOUNDARIES THIS MORNING. STALLED SURFACE BOUNDARY
ORIENTED SW-NE ACROSS NE IA AND SWRN WI WITH SOME CAPE ALONG AND
TO ITS SOUTH. MORE OF THE MARITIME TROPICAL AIR IS LOCATED SOUTH
OF A WARM-STATIONARY FRONT IN THE VICINITY OF THE IA-MO
BORDER...FEEDING WITH MUCH OF THE NOCTURNAL CONVECTION IN IA. MAIN
SYNOPTIC SURFACE LOW ASSOCIATED WITH THE STRONG-DEEP TROPOSPHERIC
SYSTEM OVER UTAH IS STILL LOCATED BACK IN WRN KS. WEAK PRESSURE
FALLS OF 1MB/3HR CENTERED OVER NEBRASKA SUGGEST THE LOW CENTER
SHOULD EJECT WEST OF OMAHA. 04.00Z NAM HAS THE BEST LOOKING SEA-
LEVEL VERIFICATION AT 06Z.
MID-UPPER LEVEL SYSTEM CENTERED OVER UT PER WATER VAPOR
IMAGERY...WITH SIGNIFICANT POTENTIAL VORTICITY IN THE SRN MOST PART
OF THE STATE WITH A TROP FOLD DOWN TO ABOUT 500MB. HAVE SOME
CONCERNS WITH UPPER JET ENERGY ON NORTHWEST SIDE OF TROUGH WITH
SPOKANE RAOB COMING IN WITH 130 KTS...WHICH 04.00Z GFS INITIALIZED
BEST BUT STILL TOO WEAK...AND 110 KTS IN SRN B.C. NET EFFECT OF
UNDER INITIALIZATION /10-15KTS/ WOULD BE TO HOLD THE MID-UPPER
TROUGH ENERGY BACK IN THE SW U.S. AND EJECT THE SRN UT ENERGY
SLIGHTLY FURTHER WEST THAN CURRENTLY FORECAST. WATER VAPOR ALSO
YIELDING A FOOTPRINT OF A SHORTWAVE TROUGH SW OF OMAHA AT 05Z
ENHANCING CONVECTION SHIFTING NORTHEAST. THIS WILL MOVE THROUGH
THE FORECAST AREA.
FOR THE MOST PART THE LATEST MODEL GUIDANCE PROVIDES SOME CONSENSUS
ON THE NEXT DAYS. BUT THE DETAILS ON TIMING ARE STILL GOING TO BE
DIFFICULT. LOOKING AT THE TRENDS IN THE MODELS...THE 12 HOUR TREND
/12-18-00Z MODEL RUNS/ AT THE SURFACE IS FOR A SLOWER AND FURTHER
SOUTHWEST POSITION TO THE SYNOPTIC FEATURES. THIS FAVORS A SURFACE
LOW IN NERN NEB BY EARLY THIS EVENING...WITH THE SLOWLY NORTHWARD
MOVING WARM FRONT JUST TO OUR SOUTH IN IA /VERSUS I-90/ AND THE
FORECAST AREA IN SE-EASTERLY FLOW...COOLER THERMAL CONDITIONS ALL DAY
FRIDAY NORTH OF THE WARM FRONT. WITH MUCH OF THE CAPE TIED TO THE
WARM SECTOR...AND THE SLOWER TIMING INTO THE OVERNIGHT FOR THE
WARM SECTOR ARRIVAL...THIS SHOULD DECREASE THE SEVERE WEATHER
POTENTIAL ACROSS THE AREA...AT LEAST FOR TORNADOES AND LARGE HAIL
AND DAMAGING WIND COVERAGE. IT APPEARS THE HIGHEST RISK IS FURTHER
WEST/SOUTH THAN YESTERDAYS FORECAST.
THIS MORNINGS SHORTWAVE TROUGH EAST OF KDSM AT 08Z LOOKS TO
CONTINUE NORTHEAST THIS MORNING BRINGING RAIN NORTHWARD. MUCAPE
ANALYSIS INDICATES ABOUT 500 J/KG FROM NE IA TO CENTRAL WI AND
SOUTHEAST. PER THE LATEST WIND PROFILES...THE LOW-LEVEL JET IS
CONVERGENT INTO SRN IA AND PER THE LATEST RAP FORECASTS...THAT THE
STRONGER FORCING REMAINS /SRN IA/ UNTIL LATER WHEN IT STARTS TO
SHIFT NORTH. HOWEVER...THE 04.07Z RAP NOW SUGGESTS A SLIGHT
MOISTURE TRANSPORT SIGNAL MOVES NORTH WITH THE SHORTWAVE INTO
CENTRAL WI. WEAK...BUT MAYBE ENOUGH TO KEEP SOME SHOWERS GOING
INTO CENTRAL WI. HAVE DETAILED THE PRECIPITATION CHANCES FOR TODAY
TO HAVE MINIMUM AROUND MID DAY AFTER MORNING RAINS...ESPECIALLY
IN THE SOUTH.
TODAY WITH BOUNDARY ACROSS THE FORECAST AREA AND THE SOUTHERN WARM
FRONT MERGING TODAY...THERE IS PLENTY OF SOUTHEAST FLOW ACROSS THE
SOUTH MAKING FOR LARGER CURVING HODOGRAPHS BY LATER AFTERNOON.
HOWEVER...THE LOW-LEVEL WIND FIELD IS NOT CONVERGENT EXCEPT ON THE
FRONT FURTHER SOUTH OF THE FORECAST AREA. THE AIR MASS SEEMS TO
HAVE LITTLE CAP INDICATED IN THE FORECAST MODELS IN THE SOUTH
AROUND MID-DAY. THUS...AS THE SYSTEM EJECTS FROM THE ROCKIES AND THE
SOUTHERLY JET INCREASES...WIDESPREAD SHOWERS AND STORMS SHOULD
DEVELOP IN ISENTROPIC LIFT AND A CONVERGENT LOW-LEVEL JET ACROSS
NRN IA BY MID-LATE AFTERNOON. THIS BROAD LIFT AND LACK OF SURFACE
CONVERGENCE IN THE FORECAST AREA SEEMS TO SUGGEST A BROAD AREA OF
COMPETING STORMS WOULD USE THE AVAILABLE CAPE....NOT A SURFACE-
BOUNDARY-FORCED CAP BREAKING EVENT WHICH WOULD FAVOR TORNADOES AND
MORE SEVERE WEATHER. THUS...IT SEEMS EMBEDDED SEVERE STORMS WITH
IN A BROADER HEAVY RAIN PRECIPITATION REGION SHOULD DEVELOP ACROSS
THE SOUTH LATER THIS AFTERNOON. THE FORCING IS BEST WEST OF THE
MISSISSIPPI RIVER.
THE SPC MODERATE RISK HAS NOT EVOLVED WEST...EVEN THOUGH THE
WEATHER SYSTEM SOLUTION HAS...TO FURTHER WEST AND SLOWER. WOULD
THINK THE MODERATE RISK IS WEST OF THE FORECAST AREA. THE BEST
THREAT FOR THE SEVERE STORMS LOOKS TO BE SOUTHWEST OF A DODGE
CENTER MN TO BOSCOBEL WISCONSIN LINE...AND WILL CHANGE FORECAST
PRODUCTS ACCORDINGLY. IT SEEMS THE LACK OF A GOOD SURFACE WARM
FRONTAL BOUNDARY AND CONVERGENCE WILL FAVOR A BROAD CONVECTIVE
MODE RATHER THAN SUPERCELLS...AND THUS A VERY REDUCED TORNADO
THREAT.
TONIGHT MAY PROVIDE A BETTER SEVERE THREAT AS THE COLD FRONT
INITIATED CONVECTIVE LINE FROM WESTERN IA SHIFTS EAST AND ARRIVES
IN THE LATE EVENING. FORCING AND DYNAMICS ARE STRONGER...BUT CAPE
IS REALLY LOWERING IN THAT 03-06Z PERIOD...HOWEVER THE FORECAST
AREA...ESPECIALLY I-90 AND SOUTH...SEEMS TO GET INTO A NARROW WARM
SECTOR REGION. SO...BOWING WIND SEGMENTS OF CONVECTION ARE
WITH WIND DAMAGE POSSIBLE. THIS IS A DIFFICULT FORECAST AS SOME
STORMS/RAIN ARE EXPECTED ASSOCIATED WITH THE WARM FRONT FORCING IN
THE HOURS PRIOR. THUS LATE EVENING AND OVERNIGHT CONVECTION MAY
BE ALL DYNAMICS AND LITTLE CAPE. NORTH OF THE TRIPLE POINT...SERN
MN INTO CENTRAL WI...HEAVY RAIN IN STRONGLY FORCED ISENTROPIC LIFT
SEEMS TO BE A STRONG SIGNAL IN THE MODELS. THERE COULD BE
LOCALIZED FLOODING THREATS THERE...DEPENDING ON RATES. THE SOILS
SHOULD BE ABLE TO HANDLE A FEW INCHES IF IT DOESNT COME AT ONCE.
WILL REISSUE AN ESF/DISCUSSION ON THIS RAIN POTENTIAL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI OCT 4 2013
THE COLD FRONT IS MOVING THROUGH THE FORECAST AREA OVERNIGHT AND
SATURDAY IT WILL BE FOUND IN CENTRAL WI AROUND MID-DAY. STORMS MAY
INITIATE ON THE FRONT...BUT IT WOULD APPEAR THE BETTER SEVERE
RISK WOULD BE EAST OF THE FORECAST AREA. SHOULD THE FRONT
SLOW...INSTABILITY WOULD IN THE LOWER CATEGORY IN HIGH
SHEAR...CAPABLE OF MINI-SUPERCELLS AND HAIL-WIND THREATS.
SUNDAY CONTINUES TO BE COOL IN THE POST-FRONTAL ENVIRONMENT. THERE
STILL APPEARS TO BE SOME TIMING AND INTENSITY DIFFERENCES WITH THE
DEFORMATION BAND OF PRECIPITATION BEHIND THE DEPARTING LOW. HAVE
DECIDED TO INCREASE PRECIPITATION CHANCES SUNDAY ESPECIALLY FURTHER
NORTHWEST.
MONDAY THROUGH THURSDAY...ANOTHER PERIOD OF ABOVE NORMAL FALL DAYS
WITH A GOOD AMOUNT OF SUNSHINE AS LONG WAVE RIDGING AGAIN BUILDS
IN. MODEL AGREEMENT AND CONFIDENCE IS HIGH FOR THIS PERIOD AS THE
LONG WAVE TROUGH DIGS OVER THE SOUTHWEST U.S. WEATHER SHOULD
BECOME MORE ACTIVE FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI OCT 4 2013
ABUNDANT LOW LEVEL MOISTURE OVER THE AREA COMBINED WITH INCREASING
LIFT AHEAD OF A STRONG MID LEVEL TROUGH AND APPROACHING SFC LOW
LOOKS TO PRODUCE AN EXTENDED PERIOD OF IFR/MVFR FOR THE AREA TODAY
THRU SAT. A FRONTAL BOUNDARY PUSHED SOUTH OF THE AREA LATE THU...AND
APPEARS AS THOUGH IT WILL STAY SOUTH OF THE AREA THRU TONIGHT. IF
THE FRONT DOES STAY SOUTH OF THE AREA...THIS WILL LIMIT THE
POTENTIAL OF SEVERE STORMS THIS AFTERNOON/EVENING. NORTH OF THIS
BOUNDARY...LOW STRATUS AND BR/FG WILL PREVAIL MUCH OF TODAY/
TONIGHT. INCREASING LIFT AHEAD OF THE APPROACHING SYSTEM WILL SEND
ROUNDS OF SHRA/TSRA ACROSS THE TAF SITES TODAY/TONIGHT. ONE OF THESE
WILL MOVE ACROSS THE AREA THIS MORNING...WITH ANOTHER ROUND EXPECTED
TO DEVELOP NORTH OF THE FRONTAL BOUNDARY ACROSS CENTRAL IA AND MOVE
ACROSS THE AREA THIS AFTERNOON/EVENING. YET ANOTHER ROUND LATER
TONIGHT AS THE SFC LOW MOVES INTO MN AND THE COLD FRONT APPROACHES.
GIVEN PLENTY OF DETAIL AND TIMING UNCERTAINTIES BEYOND THIS
MORNING...GENERALLY CARRIED VCSH/VCTS IN THE TAFS VS. LONGER PERIODS
OF SHRA/TSRA. BR/LOW STRATUS WILL GENERALLY KEEP FLIGHT CATEGORIES
IFR/MVFR WITH OR WITHOUT SHRA/TSRA...THOUGH SHRA/TSRA PASSING THU
MAY ACTUALLY RAISE THE CIGS/VSBYS. LATER TAF CYCLES OR UPDATES CAN
ADD MORE SHRA/TSRA WHEN TIMING DETAILS BECOME CLEARER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
338 AM CDT FRI OCT 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI OCT 4 2013
MOST OF THE FORECAST WAS SPENT ON TRYING TO IMPROVE THE FORECAST
TODAY THROUGH SATURDAY AND EVALUATING THE SEVERE WEATHER RISK. IT
LOOKS LIKE THERE IS A RISK...BUT THE THREAT HAS DIMINISHED
SOMEWHAT AND SHIFTED WEST.
SURFACE ANALYSIS SHOWING COMPLEX YET FAIRLY ORGANIZED AIR MASS
FRONTAL BOUNDARIES THIS MORNING. STALLED SURFACE BOUNDARY
ORIENTED SW-NE ACROSS NE IA AND SWRN WI WITH SOME CAPE ALONG AND
TO ITS SOUTH. MORE OF THE MARITIME TROPICAL AIR IS LOCATED SOUTH
OF A WARM-STATIONARY FRONT IN THE VICINITY OF THE IA-MO
BORDER...FEEDING WITH MUCH OF THE NOCTURNAL CONVECTION IN IA. MAIN
SYNOPTIC SURFACE LOW ASSOCIATED WITH THE STRONG-DEEP TROPOSPHERIC
SYSTEM OVER UTAH IS STILL LOCATED BACK IN WRN KS. WEAK PRESSURE
FALLS OF 1MB/3HR CENTERED OVER NEBRASKA SUGGEST THE LOW CENTER
SHOULD EJECT WEST OF OMAHA. 04.00Z NAM HAS THE BEST LOOKING SEA-
LEVEL VERIFICATION AT 06Z.
MID-UPPER LEVEL SYSTEM CENTERED OVER UT PER WATER VAPOR
IMAGERY...WITH SIGNIFICANT POTENTIAL VORTICITY IN THE SRN MOST PART
OF THE STATE WITH A TROP FOLD DOWN TO ABOUT 500MB. HAVE SOME
CONCERNS WITH UPPER JET ENERGY ON NORTHWEST SIDE OF TROUGH WITH
SPOKANE RAOB COMING IN WITH 130 KTS...WHICH 04.00Z GFS INITIALIZED
BEST BUT STILL TOO WEAK...AND 110 KTS IN SRN B.C. NET EFFECT OF
UNDER INITIALIZATION /10-15KTS/ WOULD BE TO HOLD THE MID-UPPER
TROUGH ENERGY BACK IN THE SW U.S. AND EJECT THE SRN UT ENERGY
SLIGHTLY FURTHER WEST THAN CURRENTLY FORECAST. WATER VAPOR ALSO
YIELDING A FOOTPRINT OF A SHORTWAVE TROUGH SW OF OMAHA AT 05Z
ENHANCING CONVECTION SHIFTING NORTHEAST. THIS WILL MOVE THROUGH
THE FORECAST AREA.
FOR THE MOST PART THE LATEST MODEL GUIDANCE PROVIDES SOME CONSENSUS
ON THE NEXT DAYS. BUT THE DETAILS ON TIMING ARE STILL GOING TO BE
DIFFICULT. LOOKING AT THE TRENDS IN THE MODELS...THE 12 HOUR TREND
/12-18-00Z MODEL RUNS/ AT THE SURFACE IS FOR A SLOWER AND FURTHER
SOUTHWEST POSITION TO THE SYNOPTIC FEATURES. THIS FAVORS A SURFACE
LOW IN NERN NEB BY EARLY THIS EVENING...WITH THE SLOWLY NORTHWARD
MOVING WARM FRONT JUST TO OUR SOUTH IN IA /VERSUS I-90/ AND THE
FORECAST AREA IN SE-EASTERLY FLOW...COOLER THERMAL CONDITIONS ALL DAY
FRIDAY NORTH OF THE WARM FRONT. WITH MUCH OF THE CAPE TIED TO THE
WARM SECTOR...AND THE SLOWER TIMING INTO THE OVERNIGHT FOR THE
WARM SECTOR ARRIVAL...THIS SHOULD DECREASE THE SEVERE WEATHER
POTENTIAL ACROSS THE AREA...AT LEAST FOR TORNADOES AND LARGE HAIL
AND DAMAGING WIND COVERAGE. IT APPEARS THE HIGHEST RISK IS FURTHER
WEST/SOUTH THAN YESTERDAYS FORECAST.
THIS MORNINGS SHORTWAVE TROUGH EAST OF KDSM AT 08Z LOOKS TO
CONTINUE NORTHEAST THIS MORNING BRINGING RAIN NORTHWARD. MUCAPE
ANALYSIS INDICATES ABOUT 500 J/KG FROM NE IA TO CENTRAL WI AND
SOUTHEAST. PER THE LATEST WIND PROFILES...THE LOW-LEVEL JET IS
CONVERGENT INTO SRN IA AND PER THE LATEST RAP FORECASTS...THAT THE
STRONGER FORCING REMAINS /SRN IA/ UNTIL LATER WHEN IT STARTS TO
SHIFT NORTH. HOWEVER...THE 04.07Z RAP NOW SUGGESTS A SLIGHT
MOISTURE TRANSPORT SIGNAL MOVES NORTH WITH THE SHORTWAVE INTO
CENTRAL WI. WEAK...BUT MAYBE ENOUGH TO KEEP SOME SHOWERS GOING
INTO CENTRAL WI. HAVE DETAILED THE PRECIPITATION CHANCES FOR TODAY
TO HAVE MINIMUM AROUND MID DAY AFTER MORNING RAINS...ESPECIALLY
IN THE SOUTH.
TODAY WITH BOUNDARY ACROSS THE FORECAST AREA AND THE SOUTHERN WARM
FRONT MERGING TODAY...THERE IS PLENTY OF SOUTHEAST FLOW ACROSS THE
SOUTH MAKING FOR LARGER CURVING HODOGRAPHS BY LATER AFTERNOON.
HOWEVER...THE LOW-LEVEL WIND FIELD IS NOT CONVERGENT EXCEPT ON THE
FRONT FURTHER SOUTH OF THE FORECAST AREA. THE AIR MASS SEEMS TO
HAVE LITTLE CAP INDICATED IN THE FORECAST MODELS IN THE SOUTH
AROUND MID-DAY. THUS...AS THE SYSTEM EJECTS FROM THE ROCKIES AND THE
SOUTHERLY JET INCREASES...WIDESPREAD SHOWERS AND STORMS SHOULD
DEVELOP IN ISENTROPIC LIFT AND A CONVERGENT LOW-LEVEL JET ACROSS
NRN IA BY MID-LATE AFTERNOON. THIS BROAD LIFT AND LACK OF SURFACE
CONVERGENCE IN THE FORECAST AREA SEEMS TO SUGGEST A BROAD AREA OF
COMPETING STORMS WOULD USE THE AVAILABLE CAPE....NOT A SURFACE-
BOUNDARY-FORCED CAP BREAKING EVENT WHICH WOULD FAVOR TORNADOES AND
MORE SEVERE WEATHER. THUS...IT SEEMS EMBEDDED SEVERE STORMS WITH
IN A BROADER HEAVY RAIN PRECIPITATION REGION SHOULD DEVELOP ACROSS
THE SOUTH LATER THIS AFTERNOON. THE FORCING IS BEST WEST OF THE
MISSISSIPPI RIVER.
THE SPC MODERATE RISK HAS NOT EVOLVED WEST...EVEN THOUGH THE
WEATHER SYSTEM SOLUTION HAS...TO FURTHER WEST AND SLOWER. WOULD
THINK THE MODERATE RISK IS WEST OF THE FORECAST AREA. THE BEST
THREAT FOR THE SEVERE STORMS LOOKS TO BE SOUTHWEST OF A DODGE
CENTER MN TO BOSCOBEL WISCONSIN LINE...AND WILL CHANGE FORECAST
PRODUCTS ACCORDINGLY. IT SEEMS THE LACK OF A GOOD SURFACE WARM
FRONTAL BOUNDARY AND CONVERGENCE WILL FAVOR A BROAD CONVECTIVE
MODE RATHER THAN SUPERCELLS...AND THUS A VERY REDUCED TORNADO
THREAT.
TONIGHT MAY PROVIDE A BETTER SEVERE THREAT AS THE COLD FRONT
INITIATED CONVECTIVE LINE FROM WESTERN IA SHIFTS EAST AND ARRIVES
IN THE LATE EVENING. FORCING AND DYNAMICS ARE STRONGER...BUT CAPE
IS REALLY LOWERING IN THAT 03-06Z PERIOD...HOWEVER THE FORECAST
AREA...ESPECIALLY I-90 AND SOUTH...SEEMS TO GET INTO A NARROW WARM
SECTOR REGION. SO...BOWING WIND SEGMENTS OF CONVECTION ARE
WITH WIND DAMAGE POSSIBLE. THIS IS A DIFFICULT FORECAST AS SOME
STORMS/RAIN ARE EXPECTED ASSOCIATED WITH THE WARM FRONT FORCING IN
THE HOURS PRIOR. THUS LATE EVENING AND OVERNIGHT CONVECTION MAY
BE ALL DYNAMICS AND LITTLE CAPE. NORTH OF THE TRIPLE POINT...SERN
MN INTO CENTRAL WI...HEAVY RAIN IN STRONGLY FORCED ISENTROPIC LIFT
SEEMS TO BE A STRONG SIGNAL IN THE MODELS. THERE COULD BE
LOCALIZED FLOODING THREATS THERE...DEPENDING ON RATES. THE SOILS
SHOULD BE ABLE TO HANDLE A FEW INCHES IF IT DOESNT COME AT ONCE.
WILL REISSUE AN ESF/DISCUSSION ON THIS RAIN POTENTIAL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI OCT 4 2013
THE COLD FRONT IS MOVING THROUGH THE FORECAST AREA OVERNIGHT AND
SATURDAY IT WILL BE FOUND IN CENTRAL WI AROUND MID-DAY. STORMS MAY
INITIATE ON THE FRONT...BUT IT WOULD APPEAR THE BETTER SEVERE
RISK WOULD BE EAST OF THE FORECAST AREA. SHOULD THE FRONT
SLOW...INSTABILITY WOULD IN THE LOWER CATEGORY IN HIGH
SHEAR...CAPABLE OF MINI-SUPERCELLS AND HAIL-WIND THREATS.
SUNDAY CONTINUES TO BE COOL IN THE POST-FRONTAL ENVIRONMENT. THERE
STILL APPEARS TO BE SOME TIMING AND INTENSITY DIFFERENCES WITH THE
DEFORMATION BAND OF PRECIPITATION BEHIND THE DEPARTING LOW. HAVE
DECIDED TO INCREASE PRECIPITATION CHANCES SUNDAY ESPECIALLY FURTHER
NORTHWEST.
MONDAY THROUGH THURSDAY...ANOTHER PERIOD OF ABOVE NORMAL FALL DAYS
WITH A GOOD AMOUNT OF SUNSHINE AS LONG WAVE RIDGING AGAIN BUILDS
IN. MODEL AGREEMENT AND CONFIDENCE IS HIGH FOR THIS PERIOD AS THE
LONG WAVE TROUGH DIGS OVER THE SOUTHWEST U.S. WEATHER SHOULD
BECOME MORE ACTIVE FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1131 PM CDT THU OCT 3 2013
WITH THE MAIN BOUNDARY NOW SOUTH OF BOTH TAF SITES THE CONCERN FOR
THE OVERNIGHT HAS SHIFTED TO IFR CONDITIONS DUE TO FOG AND
CEILINGS. THE FOG HAS SETTLED IN OVER KRST AND INDICATIONS ARE
THAT IT WILL REMAIN FOR THE NIGHT WITH LITTLE TO NO TEMP/DEW POINT
SPREAD AND ONLY LIGHT NORTH WINDS. THE 04.02Z RAP FORECAST
SOUNDINGS SHOW NO SIGNIFICANT CHANGES OCCURRING OVERNIGHT SO WILL
LEAVE THE LIFR CONDITIONS IN PLACE UNTIL THE MIDDLE OF FRIDAY
MORNING WHEN SOME IMPROVEMENT COULD OCCUR IF THE CONVECTION OVER
SOUTHWEST IOWA CAN MOVE INTO THE AREA AND CLEAN THE ATMOSPHERE
OUT. FOG HAS YET TO DEVELOP IN THE MISSISSIPPI RIVER VALLEY BUT
THE LOW CEILINGS ARE IN PLACE. HOWEVER...WITH ONLY A 2 DEGREE
TEMP/DEW POINT SPREAD AT 04Z...EXPECT TO SEE THE FOG FORM WITH THE
VISIBILITY GOING DOWN TO IFR OVERNIGHT. CONSIDERABLE UNCERTAINTY
STILL EXISTS ON HOW FRIDAY WILL PLAY OUT IN THE AFTERNOON AND
EVENING. THE 04.00Z NAM SUGGESTS THE BOUNDARY WILL STAY SOUTH OF
BOTH TAF SITES THROUGH THE EVENING AS THE MAIN SURFACE LOW MOVES
INTO SOUTHEAST SOUTH DAKOTA OR SOUTHWEST MINNESOTA. IT DOES
SUGGEST THAT A LEAD SHORT WAVE TROUGH COULD TRACK OVER THE AREA
DURING THE AFTERNOON AND EVENING TO SPARK CONVECTION ALONG AND
NORTH OF THE BOUNDARY SO HAVE INCLUDED VCTS AT BOTH SITES TO HAND
THIS. OTHERWISE...THE BEST CHANCE FOR CONVECTION MAY NOT OCCUR
UNTIL LATE FRIDAY EVENING INTO THE OVERNIGHT HOURS AS THE COLD
FRONT APPROACHES FROM THE WEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1131 PM CDT THU OCT 3 2013
.UPDATE...
ISSUED AT 747 PM CDT THU OCT 3 2013
THE MAIN SURFACE BOUNDARY HAS BEEN SLIPPING SLOWLY SOUTH THROUGH
THE AREA THIS EVENING AND NOW EXTENDS FROM ABOUT KDLL TO KIFA.
TRENDS IN THE HRRR HAVE BEEN FOR THE BOUNDARY TO CONTINUE SLIPPING
TO THE SOUTH AS IT BECOMES ORIENTED A LITTLE MORE EAST/WEST
EVENTUALLY SETTLING IN OVER THE FAR SOUTHERN PARTS OF THE
FORECAST AREA OR A LITTLE FARTHER SOUTH AND THEN REMAIN THERE IN
FRIDAY MORNING. A WEAK SHORT WAVE TROUGH IS COMING ACROSS NEBRASKA
AND KANSAS THAT WILL INITIATE CONVECTION ALONG THE BOUNDARY AS THE
LOW LEVEL JET GETS CRANKED UP. SIGNS OF THIS STARTING TO OCCUR
OVER SOUTHERN IOWA AND THIS SHOULD THEN MOVE NORTHEAST ALONG THE
BOUNDARY GIVING THE BEST CHANCE FOR ADDITIONAL SHOWERS AND STORMS
OVERNIGHT ACROSS THE SOUTH. HAVE ALREADY ADJUSTED THE RAIN CHANCES
TO SHOW THE HIGHEST CHANCES ACROSS THE SOUTH FOR THE OVERNIGHT.
FURTHER ADJUSTMENTS MAY BE MADE TO LIMIT THE THUNDER CHANCES TO
THE SOUTH AS WELL AND POSSIBLY GO TO MORE A DRIZZLE EVENT NORTH OF
THE BOUNDARY. FOG ALSO DEVELOPING NORTH OF THE BOUNDARY AND WILL
HAVE TO MONITOR THE POSSIBLE DEVELOPMENT OF DENSE FOG.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM CDT THU OCT 3 2013
MAIN FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL FRIDAY
INTO FRIDAY NIGHT WITH THE POSSIBILITY OF HEAVY RAIN...LARGE
HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES.
LATEST WATER VAPOR IMAGERY SHOWED SEVERAL SHORTWAVE MOVING ACROSS
THE UPPER MIDWEST. THE LEADING SHORTWAVE WAS MOVING OVER THE
FORECAST AREA THIS AFTERNOON...PRODUCING SHOWERS AND THUNDERSTORMS.
THE MAIN FEATURE TO KEY IN ON IS A POTENT UPPER LOW DIGGING INTO THE
CENTRAL ROCKIES. THIS FEATURE WILL EJECT EASTWARD INTO THE PLAINS
DRIVING A SURFACE LOW AND WARM FRONT INTO THE REGION FRIDAY INTO
FRIDAY NIGHT. MEANWHILE...SURFACE OBSERVATIONS SHOWED A VERY MOIST
AIRMASS SURGING INTO THE FORECAST AREA WITH DEWPOINTS CLIMBING INTO
UPPER 60S ACROSS ALL OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
SHOWER AND THUNDERSTORMS SHOULD GRADUALLY MOVE NORTHEAST...IMPACTING
CENTRAL AND NORTH CENTRAL WISCONSIN LATE THIS AFTERNOON INTO EARLY
THIS EVENING THEN TAPERING OFF. ANOTHER ROUND OF SHOWER AND STORMS
ARE EXPECTED TO REDEVELOP TONIGHT AS A STRONG LOW LEVEL JET FOCUSES
INTO AREAS ALONG AND SOUTH OF INTERSTATE 90...POSSIBLY IMPACTING
MOST AREAS SOUTH AND WEST OF THE INTERSTATE 94 CORRIDOR. ANY STORMS
THAT DEVELOP TONIGHT WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL
WITH PRECIPITABLE WATER VALUES 1.4 TO 1.6 INCHES...WHICH IS RIGHT
AROUND 200 PERCENT OF NORMAL. IN ADDITION...WARM CLOUD DEPTHS HOVER
AROUND 3.5 KM. WILL HAVE TO KEEP A VERY CLOSE WATCH ON RAINFALL
AMOUNTS TONIGHT...ESPECIALLY ACROSS AREAS THAT RECEIVED HEAVIER
RAINS TODAY. CANNOT RULE OUT SOME SMALL TO POSSIBLY LARGE HAIL
TONIGHT WITH THE SOME OF THE STRONGER STORMS...WITH 0-3KM MUCAPE
VALUES CLIMBING TO AROUND 1500 J/KG LATE TONIGHT.
FOCUS QUICKLY TURNS TO FRIDAY AS A WARM FRONT LIFTS INTO THE REGION
AND SURFACE LOW PRESSURE DEEPENS OVER NORTHEAST NEBRASKA AND LIFTS
INTO SOUTHWEST MINNESOTA. A WARM FRONT SHOULD BE SET UP FROM
NORTHWEST IOWA THROUGH NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN BY
EARLY FRIDAY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER
NORTHWEST IOWA/SOUTHWEST MINNESOTA BY MID AFTERNOON AND WILL RACE
EAST INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND EVENING
HOURS. ALSO...CANNOT RULE OUT A STORM OR TWO DEVELOPING IN THE WARM
SECTOR FURTHER EAST OVER NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
THESE STORMS WOULD LIKELY BE SUPERCELLS...WITH 0-6 KM BULK SHEAR
VALUES OF 40 TO 45 KTS. INTERESTING TO NOTE THAT MUCH OF THIS SHEAR
IS LOCATED IN THE 0-3 KM LAYER. THE SUPERCELLS COULD FORM INTO BOWS
AS THEY RACE EAST WITH AN ENHANCED THREAT FOR DAMAGING WINDS AND
PERHAPS AN EMBEDDED TORNADO OR TWO. THE WARM FRONT LIFTS NORTH TO
ALONG THE INTERSTATE 90 CORRIDOR BY EARLY FRIDAY EVENING. THE BEST
PARAMETERS FOR TORNADOES APPEARS TO BE WEST OF THE MISSISSIPPI RIVER
IN THE 21Z TO 4Z TIMEFRAME...THEN SHIFTING NORTHEAST. ONE OF THE
BIGGEST CONCERNS IS THE RAPID INCREASE IN 0-1KM BULK SHEAR IN THE
00Z TO 03Z TIMEFRAME WHEN VALUES GO FROM 20 TO 25KTS TO AROUND 40
KTS. AS THE STORMS WORK EAST THEY WILL BE ENCOUNTERING THIS STRONGER
LOWER LEVEL SHEAR. THE STORMS SHOULD PUSH TO ALONG THE MISSISSIPPI
RIVER IN THE LATE EVENING TO LATE NIGHT HOURS. THE STORMS WILL THEN
PUSH INTO WESTERN WISCONSIN AND MAY STILL BE SEVERE WITH DAMAGING
WINDS...LARGE HAIL...AND ISOLATED TORNADOES. THE VERY MOIST AIRMASS
WILL REMAIN IN PLACE FRIDAY NIGHT AND COULD LEAD TO THE POTENTIAL
FOR HEAVY RAIN AND POSSIBLY SOME LOCALIZED FLOODING CONCERNS. A
FLASH FLOOD WATCH MAY BE NEEDED. THE COLD FRONT LOOKS TO PUSH
THROUGH THE FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 356 PM CDT THU OCT 3 2013
SHOWERS AND STORMS WILL LIKELY BE ONGOING SATURDAY MORNING. ANOTHER
ROUND OF STRONG TO POSSIBLY SEVERE STORM COULD OCCUR OVER WESTERN AN
CENTRAL WISCONSIN EARLY SATURDAY AFTERNOON BUT THIS WILL DEPEND ON
THE TIMING OF THE COLD FRONT. THE LOW PRESSURE SYSTEM THEN FINALLY
LIFTS NORTHEAST OF THE AREA SATURDAY NIGHT INTO SUNDAY. MUCH OF THE
AREA WILL LIKELY BE DRY SLOTTED SATURDAY NIGHT INTO EARLY SUNDAY
MORNING. WRAP AROUND MOISTURE ON THE BACK SIDE OF THE LOW COULD BRING
SOME SHOWERS TO THE AREA ON SUNDAY. MUCH COOLER AIR WILL MOVE INTO
THE REGION SATURDAY NIGHT WITH TEMPERATURES FALLING INTO THE UPPER
30S TO LOWER 40S. HIGHS ON SUNDAY WILL ONLY BE IN THE 50S. HIGH
PRESSURE LOOKS TO BUILD OVER THE REGION MONDAY AND REMAINS OVER THE
AREA THROUGH THURSDAY. DRY WEATHER IS EXPECTED THROUGH THE PERIOD
WITH HIGHS WARMING INTO THE 60S ON MONDAY AND TUESDAY. HIGHS WARM
INTO THE 70S ON WEDNESDAY AND THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1131 PM CDT THU OCT 3 2013
WITH THE MAIN BOUNDARY NOW SOUTH OF BOTH TAF SITES THE CONCERN FOR
THE OVERNIGHT HAS SHIFTED TO IFR CONDITIONS DUE TO FOG AND
CEILINGS. THE FOG HAS SETTLED IN OVER KRST AND INDICATIONS ARE
THAT IT WILL REMAIN FOR THE NIGHT WITH LITTLE TO NO TEMP/DEW POINT
SPREAD AND ONLY LIGHT NORTH WINDS. THE 04.02Z RAP FORECAST
SOUNDINGS SHOW NO SIGNIFICANT CHANGES OCCURRING OVERNIGHT SO WILL
LEAVE THE LIFR CONDITIONS IN PLACE UNTIL THE MIDDLE OF FRIDAY
MORNING WHEN SOME IMPROVEMENT COULD OCCUR IF THE CONVECTION OVER
SOUTHWEST IOWA CAN MOVE INTO THE AREA AND CLEAN THE ATMOSPHERE
OUT. FOG HAS YET TO DEVELOP IN THE MISSISSIPPI RIVER VALLEY BUT
THE LOW CEILINGS ARE IN PLACE. HOWEVER...WITH ONLY A 2 DEGREE
TEMP/DEW POINT SPREAD AT 04Z...EXPECT TO SEE THE FOG FORM WITH THE
VISIBILITY GOING DOWN TO IFR OVERNIGHT. CONSIDERABLE UNCERTAINTY
STILL EXISTS ON HOW FRIDAY WILL PLAY OUT IN THE AFTERNOON AND
EVENING. THE 04.00Z NAM SUGGESTS THE BOUNDARY WILL STAY SOUTH OF
BOTH TAF SITES THROUGH THE EVENING AS THE MAIN SURFACE LOW MOVES
INTO SOUTHEAST SOUTH DAKOTA OR SOUTHWEST MINNESOTA. IT DOES
SUGGEST THAT A LEAD SHORT WAVE TROUGH COULD TRACK OVER THE AREA
DURING THE AFTERNOON AND EVENING TO SPARK CONVECTION ALONG AND
NORTH OF THE BOUNDARY SO HAVE INCLUDED VCTS AT BOTH SITES TO HAND
THIS. OTHERWISE...THE BEST CHANCE FOR CONVECTION MAY NOT OCCUR
UNTIL LATE FRIDAY EVENING INTO THE OVERNIGHT HOURS AS THE COLD
FRONT APPROACHES FROM THE WEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
747 PM CDT THU OCT 3 2013
.UPDATE...
ISSUED AT 747 PM CDT THU OCT 3 2013
THE MAIN SURFACE BOUNDARY HAS BEEN SLIPPING SLOWLY SOUTH THROUGH
THE AREA THIS EVENING AND NOW EXTENDS FROM ABOUT KDLL TO KIFA.
TRENDS IN THE HRRR HAVE BEEN FOR THE BOUNDARY TO CONTINUE SLIPPING
TO THE SOUTH AS IT BECOMES ORIENTED A LITTLE MORE EAST/WEST
EVENTUALLY SETTLING IN OVER THE FAR SOUTHERN PARTS OF THE
FORECAST AREA OR A LITTLE FARTHER SOUTH AND THEN REMAIN THERE IN
FRIDAY MORNING. A WEAK SHORT WAVE TROUGH IS COMING ACROSS NEBRASKA
AND KANSAS THAT WILL INITIATE CONVECTION ALONG THE BOUNDARY AS THE
LOW LEVEL JET GETS CRANKED UP. SIGNS OF THIS STARTING TO OCCUR
OVER SOUTHERN IOWA AND THIS SHOULD THEN MOVE NORTHEAST ALONG THE
BOUNDARY GIVING THE BEST CHANCE FOR ADDITIONAL SHOWERS AND STORMS
OVERNIGHT ACROSS THE SOUTH. HAVE ALREADY ADJUSTED THE RAIN CHANCES
TO SHOW THE HIGHEST CHANCES ACROSS THE SOUTH FOR THE OVERNIGHT.
FURTHER ADJUSTMENTS MAY BE MADE TO LIMIT THE THUNDER CHANCES TO
THE SOUTH AS WELL AND POSSIBLY GO TO MORE A DRIZZLE EVENT NORTH OF
THE BOUNDARY. FOG ALSO DEVELOPING NORTH OF THE BOUNDARY AND WILL
HAVE TO MONITOR THE POSSIBLE DEVELOPMENT OF DENSE FOG.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM CDT THU OCT 3 2013
MAIN FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL FRIDAY
INTO FRIDAY NIGHT WITH THE POSSIBILITY OF HEAVY RAIN...LARGE
HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES.
LATEST WATER VAPOR IMAGERY SHOWED SEVERAL SHORTWAVE MOVING ACROSS
THE UPPER MIDWEST. THE LEADING SHORTWAVE WAS MOVING OVER THE
FORECAST AREA THIS AFTERNOON...PRODUCING SHOWERS AND THUNDERSTORMS.
THE MAIN FEATURE TO KEY IN ON IS A POTENT UPPER LOW DIGGING INTO THE
CENTRAL ROCKIES. THIS FEATURE WILL EJECT EASTWARD INTO THE PLAINS
DRIVING A SURFACE LOW AND WARM FRONT INTO THE REGION FRIDAY INTO
FRIDAY NIGHT. MEANWHILE...SURFACE OBSERVATIONS SHOWED A VERY MOIST
AIRMASS SURGING INTO THE FORECAST AREA WITH DEWPOINTS CLIMBING INTO
UPPER 60S ACROSS ALL OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
SHOWER AND THUNDERSTORMS SHOULD GRADUALLY MOVE NORTHEAST...IMPACTING
CENTRAL AND NORTH CENTRAL WISCONSIN LATE THIS AFTERNOON INTO EARLY
THIS EVENING THEN TAPERING OFF. ANOTHER ROUND OF SHOWER AND STORMS
ARE EXPECTED TO REDEVELOP TONIGHT AS A STRONG LOW LEVEL JET FOCUSES
INTO AREAS ALONG AND SOUTH OF INTERSTATE 90...POSSIBLY IMPACTING
MOST AREAS SOUTH AND WEST OF THE INTERSTATE 94 CORRIDOR. ANY STORMS
THAT DEVELOP TONIGHT WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL
WITH PRECIPITABLE WATER VALUES 1.4 TO 1.6 INCHES...WHICH IS RIGHT
AROUND 200 PERCENT OF NORMAL. IN ADDITION...WARM CLOUD DEPTHS HOVER
AROUND 3.5 KM. WILL HAVE TO KEEP A VERY CLOSE WATCH ON RAINFALL
AMOUNTS TONIGHT...ESPECIALLY ACROSS AREAS THAT RECEIVED HEAVIER
RAINS TODAY. CANNOT RULE OUT SOME SMALL TO POSSIBLY LARGE HAIL
TONIGHT WITH THE SOME OF THE STRONGER STORMS...WITH 0-3KM MUCAPE
VALUES CLIMBING TO AROUND 1500 J/KG LATE TONIGHT.
FOCUS QUICKLY TURNS TO FRIDAY AS A WARM FRONT LIFTS INTO THE REGION
AND SURFACE LOW PRESSURE DEEPENS OVER NORTHEAST NEBRASKA AND LIFTS
INTO SOUTHWEST MINNESOTA. A WARM FRONT SHOULD BE SET UP FROM
NORTHWEST IOWA THROUGH NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN BY
EARLY FRIDAY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER
NORTHWEST IOWA/SOUTHWEST MINNESOTA BY MID AFTERNOON AND WILL RACE
EAST INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND EVENING
HOURS. ALSO...CANNOT RULE OUT A STORM OR TWO DEVELOPING IN THE WARM
SECTOR FURTHER EAST OVER NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
THESE STORMS WOULD LIKELY BE SUPERCELLS...WITH 0-6 KM BULK SHEAR
VALUES OF 40 TO 45 KTS. INTERESTING TO NOTE THAT MUCH OF THIS SHEAR
IS LOCATED IN THE 0-3 KM LAYER. THE SUPERCELLS COULD FORM INTO BOWS
AS THEY RACE EAST WITH AN ENHANCED THREAT FOR DAMAGING WINDS AND
PERHAPS AN EMBEDDED TORNADO OR TWO. THE WARM FRONT LIFTS NORTH TO
ALONG THE INTERSTATE 90 CORRIDOR BY EARLY FRIDAY EVENING. THE BEST
PARAMETERS FOR TORNADOES APPEARS TO BE WEST OF THE MISSISSIPPI RIVER
IN THE 21Z TO 4Z TIMEFRAME...THEN SHIFTING NORTHEAST. ONE OF THE
BIGGEST CONCERNS IS THE RAPID INCREASE IN 0-1KM BULK SHEAR IN THE
00Z TO 03Z TIMEFRAME WHEN VALUES GO FROM 20 TO 25KTS TO AROUND 40
KTS. AS THE STORMS WORK EAST THEY WILL BE ENCOUNTERING THIS STRONGER
LOWER LEVEL SHEAR. THE STORMS SHOULD PUSH TO ALONG THE MISSISSIPPI
RIVER IN THE LATE EVENING TO LATE NIGHT HOURS. THE STORMS WILL THEN
PUSH INTO WESTERN WISCONSIN AND MAY STILL BE SEVERE WITH DAMAGING
WINDS...LARGE HAIL...AND ISOLATED TORNADOES. THE VERY MOIST AIRMASS
WILL REMAIN IN PLACE FRIDAY NIGHT AND COULD LEAD TO THE POTENTIAL
FOR HEAVY RAIN AND POSSIBLY SOME LOCALIZED FLOODING CONCERNS. A
FLASH FLOOD WATCH MAY BE NEEDED. THE COLD FRONT LOOKS TO PUSH
THROUGH THE FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 356 PM CDT THU OCT 3 2013
SHOWERS AND STORMS WILL LIKELY BE ONGOING SATURDAY MORNING. ANOTHER
ROUND OF STRONG TO POSSIBLY SEVERE STORM COULD OCCUR OVER WESTERN AN
CENTRAL WISCONSIN EARLY SATURDAY AFTERNOON BUT THIS WILL DEPEND ON
THE TIMING OF THE COLD FRONT. THE LOW PRESSURE SYSTEM THEN FINALLY
LIFTS NORTHEAST OF THE AREA SATURDAY NIGHT INTO SUNDAY. MUCH OF THE
AREA WILL LIKELY BE DRY SLOTTED SATURDAY NIGHT INTO EARLY SUNDAY
MORNING. WRAP AROUND MOISTURE ON THE BACK SIDE OF THE LOW COULD BRING
SOME SHOWERS TO THE AREA ON SUNDAY. MUCH COOLER AIR WILL MOVE INTO
THE REGION SATURDAY NIGHT WITH TEMPERATURES FALLING INTO THE UPPER
30S TO LOWER 40S. HIGHS ON SUNDAY WILL ONLY BE IN THE 50S. HIGH
PRESSURE LOOKS TO BUILD OVER THE REGION MONDAY AND REMAINS OVER THE
AREA THROUGH THURSDAY. DRY WEATHER IS EXPECTED THROUGH THE PERIOD
WITH HIGHS WARMING INTO THE 60S ON MONDAY AND TUESDAY. HIGHS WARM
INTO THE 70S ON WEDNESDAY AND THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 606 PM CDT THU OCT 3 2013
THE MAIN SURFACE BOUNDARY HAS DROPPED SOUTH OF BOTH TAF SITES
ALLOWING THE WINDS TO COME AROUND TO THE EAST/NORTHEAST AND FOR
THE DEVELOPMENT OF MVFR CEILINGS. THE 03.18Z NAM AND 03.20Z HRRR
BOTH SUGGEST THAT THE BOUNDARY WILL STAY TO THE SOUTH FOR MUCH OF
THIS PERIOD. WITH WEAK OVERRUNNING OF THE BOUNDARY...EXPECT TO SEE
THE MVFR CEILINGS CONTINUE WITH KRST LIKELY GOING DOWN TO IFR.
SATURATION NORTH OF THE BOUNDARY WILL LIKELY LEAD TO THE FORMATION
OF FOG AS WELL AND HAVE TAKEN BOTH SITES DOWN TO MVFR THIS EVENING
AND THEN IFR OVERNIGHT. NOT SURE HOW MUCH CONVECTION WILL OCCUR
NORTH OF THE FRONT WITH THE HRRR AND 03.12Z HI RES ARW SUGGESTING
IT WILL BE MORE ALONG AND SOUTH OF THE BOUNDARY THROUGH THE NIGHT.
HAVE THUS ONLY INCLUDED A VCTS FOR BOTH SITES AS A WEAK SHORT
WAVE TROUGH OVER NEBRASKA AND KANSAS TRACKS ACROSS THE AREA.
SHOULD BE A BREAK IN ANY ACTIVITY TOMORROW MORNING FROM ANY
ACTIVITY THAT DOES DEVELOP OVERNIGHT. THE FLOW WILL BECOME MORE
SOUTHEAST FRIDAY AFTERNOON AHEAD OF STRONG AREA OF LOW PRESSURE
DEVELOPING OVER NEBRASKA. THE MAIN BOUNDARY SHOULD STILL BE SOUTH
OF THE AREA...BUT HOPEFULLY THE TURN IN THE WINDS WILL BE ENOUGH
TO ALLOW THE VISIBILITY TO COME UP TO VFR BUT WILL HOLD THE
CEILINGS AT MVFR. WILL ALSO INCLUDE A VCTS FOR THE LATE AFTERNOON
BUT EXPECTING MOST OF THE ACTIVITY TO HOLD OFF UNTIL THE EVENING
HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
606 PM CDT THU OCT 3 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 356 PM CDT THU OCT 3 2013
MAIN FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL FRIDAY
INTO FRIDAY NIGHT WITH THE POSSIBILITY OF HEAVY RAIN...LARGE
HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES.
LATEST WATER VAPOR IMAGERY SHOWED SEVERAL SHORTWAVE MOVING ACROSS
THE UPPER MIDWEST. THE LEADING SHORTWAVE WAS MOVING OVER THE
FORECAST AREA THIS AFTERNOON...PRODUCING SHOWERS AND THUNDERSTORMS.
THE MAIN FEATURE TO KEY IN ON IS A POTENT UPPER LOW DIGGING INTO THE
CENTRAL ROCKIES. THIS FEATURE WILL EJECT EASTWARD INTO THE PLAINS
DRIVING A SURFACE LOW AND WARM FRONT INTO THE REGION FRIDAY INTO
FRIDAY NIGHT. MEANWHILE...SURFACE OBSERVATIONS SHOWED A VERY MOIST
AIRMASS SURGING INTO THE FORECAST AREA WITH DEWPOINTS CLIMBING INTO
UPPER 60S ACROSS ALL OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
SHOWER AND THUNDERSTORMS SHOULD GRADUALLY MOVE NORTHEAST...IMPACTING
CENTRAL AND NORTH CENTRAL WISCONSIN LATE THIS AFTERNOON INTO EARLY
THIS EVENING THEN TAPERING OFF. ANOTHER ROUND OF SHOWER AND STORMS
ARE EXPECTED TO REDEVELOP TONIGHT AS A STRONG LOW LEVEL JET FOCUSES
INTO AREAS ALONG AND SOUTH OF INTERSTATE 90...POSSIBLY IMPACTING
MOST AREAS SOUTH AND WEST OF THE INTERSTATE 94 CORRIDOR. ANY STORMS
THAT DEVELOP TONIGHT WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL
WITH PRECIPITABLE WATER VALUES 1.4 TO 1.6 INCHES...WHICH IS RIGHT
AROUND 200 PERCENT OF NORMAL. IN ADDITION...WARM CLOUD DEPTHS HOVER
AROUND 3.5 KM. WILL HAVE TO KEEP A VERY CLOSE WATCH ON RAINFALL
AMOUNTS TONIGHT...ESPECIALLY ACROSS AREAS THAT RECEIVED HEAVIER
RAINS TODAY. CANNOT RULE OUT SOME SMALL TO POSSIBLY LARGE HAIL
TONIGHT WITH THE SOME OF THE STRONGER STORMS...WITH 0-3KM MUCAPE
VALUES CLIMBING TO AROUND 1500 J/KG LATE TONIGHT.
FOCUS QUICKLY TURNS TO FRIDAY AS A WARM FRONT LIFTS INTO THE REGION
AND SURFACE LOW PRESSURE DEEPENS OVER NORTHEAST NEBRASKA AND LIFTS
INTO SOUTHWEST MINNESOTA. A WARM FRONT SHOULD BE SET UP FROM
NORTHWEST IOWA THROUGH NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN BY
EARLY FRIDAY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER
NORTHWEST IOWA/SOUTHWEST MINNESOTA BY MID AFTERNOON AND WILL RACE
EAST INTO THE FORECAST AREA DURING THE LATE AFTERNOON AND EVENING
HOURS. ALSO...CANNOT RULE OUT A STORM OR TWO DEVELOPING IN THE WARM
SECTOR FURTHER EAST OVER NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
THESE STORMS WOULD LIKELY BE SUPERCELLS...WITH 0-6 KM BULK SHEAR
VALUES OF 40 TO 45 KTS. INTERESTING TO NOTE THAT MUCH OF THIS SHEAR
IS LOCATED IN THE 0-3 KM LAYER. THE SUPERCELLS COULD FORM INTO BOWS
AS THEY RACE EAST WITH AN ENHANCED THREAT FOR DAMAGING WINDS AND
PERHAPS AN EMBEDDED TORNADO OR TWO. THE WARM FRONT LIFTS NORTH TO
ALONG THE INTERSTATE 90 CORRIDOR BY EARLY FRIDAY EVENING. THE BEST
PARAMETERS FOR TORNADOES APPEARS TO BE WEST OF THE MISSISSIPPI RIVER
IN THE 21Z TO 4Z TIMEFRAME...THEN SHIFTING NORTHEAST. ONE OF THE
BIGGEST CONCERNS IS THE RAPID INCREASE IN 0-1KM BULK SHEAR IN THE
00Z TO 03Z TIMEFRAME WHEN VALUES GO FROM 20 TO 25KTS TO AROUND 40
KTS. AS THE STORMS WORK EAST THEY WILL BE ENCOUNTERING THIS STRONGER
LOWER LEVEL SHEAR. THE STORMS SHOULD PUSH TO ALONG THE MISSISSIPPI
RIVER IN THE LATE EVENING TO LATE NIGHT HOURS. THE STORMS WILL THEN
PUSH INTO WESTERN WISCONSIN AND MAY STILL BE SEVERE WITH DAMAGING
WINDS...LARGE HAIL...AND ISOLATED TORNADOES. THE VERY MOIST AIRMASS
WILL REMAIN IN PLACE FRIDAY NIGHT AND COULD LEAD TO THE POTENTIAL
FOR HEAVY RAIN AND POSSIBLY SOME LOCALIZED FLOODING CONCERNS. A
FLASH FLOOD WATCH MAY BE NEEDED. THE COLD FRONT LOOKS TO PUSH
THROUGH THE FORECAST AREA LATE FRIDAY NIGHT INTO SATURDAY MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 356 PM CDT THU OCT 3 2013
SHOWERS AND STORMS WILL LIKELY BE ONGOING SATURDAY MORNING. ANOTHER
ROUND OF STRONG TO POSSIBLY SEVERE STORM COULD OCCUR OVER WESTERN AN
CENTRAL WISCONSIN EARLY SATURDAY AFTERNOON BUT THIS WILL DEPEND ON
THE TIMING OF THE COLD FRONT. THE LOW PRESSURE SYSTEM THEN FINALLY
LIFTS NORTHEAST OF THE AREA SATURDAY NIGHT INTO SUNDAY. MUCH OF THE
AREA WILL LIKELY BE DRY SLOTTED SATURDAY NIGHT INTO EARLY SUNDAY
MORNING. WRAP AROUND MOISTURE ON THE BACK SIDE OF THE LOW COULD BRING
SOME SHOWERS TO THE AREA ON SUNDAY. MUCH COOLER AIR WILL MOVE INTO
THE REGION SATURDAY NIGHT WITH TEMPERATURES FALLING INTO THE UPPER
30S TO LOWER 40S. HIGHS ON SUNDAY WILL ONLY BE IN THE 50S. HIGH
PRESSURE LOOKS TO BUILD OVER THE REGION MONDAY AND REMAINS OVER THE
AREA THROUGH THURSDAY. DRY WEATHER IS EXPECTED THROUGH THE PERIOD
WITH HIGHS WARMING INTO THE 60S ON MONDAY AND TUESDAY. HIGHS WARM
INTO THE 70S ON WEDNESDAY AND THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 606 PM CDT THU OCT 3 2013
THE MAIN SURFACE BOUNDARY HAS DROPPED SOUTH OF BOTH TAF SITES
ALLOWING THE WINDS TO COME AROUND TO THE EAST/NORTHEAST AND FOR
THE DEVELOPMENT OF MVFR CEILINGS. THE 03.18Z NAM AND 03.20Z HRRR
BOTH SUGGEST THAT THE BOUNDARY WILL STAY TO THE SOUTH FOR MUCH OF
THIS PERIOD. WITH WEAK OVERRUNNING OF THE BOUNDARY...EXPECT TO SEE
THE MVFR CEILINGS CONTINUE WITH KRST LIKELY GOING DOWN TO IFR.
SATURATION NORTH OF THE BOUNDARY WILL LIKELY LEAD TO THE FORMATION
OF FOG AS WELL AND HAVE TAKEN BOTH SITES DOWN TO MVFR THIS EVENING
AND THEN IFR OVERNIGHT. NOT SURE HOW MUCH CONVECTION WILL OCCUR
NORTH OF THE FRONT WITH THE HRRR AND 03.12Z HI RES ARW SUGGESTING
IT WILL BE MORE ALONG AND SOUTH OF THE BOUNDARY THROUGH THE NIGHT.
HAVE THUS ONLY INCLUDED A VCTS FOR BOTH SITES AS A WEAK SHORT
WAVE TROUGH OVER NEBRASKA AND KANSAS TRACKS ACROSS THE AREA.
SHOULD BE A BREAK IN ANY ACTIVITY TOMORROW MORNING FROM ANY
ACTIVITY THAT DOES DEVELOP OVERNIGHT. THE FLOW WILL BECOME MORE
SOUTHEAST FRIDAY AFTERNOON AHEAD OF STRONG AREA OF LOW PRESSURE
DEVELOPING OVER NEBRASKA. THE MAIN BOUNDARY SHOULD STILL BE SOUTH
OF THE AREA...BUT HOPEFULLY THE TURN IN THE WINDS WILL BE ENOUGH
TO ALLOW THE VISIBILITY TO COME UP TO VFR BUT WILL HOLD THE
CEILINGS AT MVFR. WILL ALSO INCLUDE A VCTS FOR THE LATE AFTERNOON
BUT EXPECTING MOST OF THE ACTIVITY TO HOLD OFF UNTIL THE EVENING
HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1243 PM CDT THU OCT 3 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 345 AM CDT THU OCT 3 2013
MAIN CONCERN IS FOCUSED ON POTENT STORM SYSTEM AFFECTING THE AREA
TODAY AND INTO THE WEEKEND.
WATER VAPOR AND RAP 500MB ANALYSIS SHOWING A WEAK MID-LEVEL
SHORTWAVE EXTENDING FROM WESTERN MN INTO EASTERN NEB. AT THE
SURFACE...A WEAK SURFACE 1009MB LOW WAS ANALYZED JUST EAST OF KFSD
WITH A TROUGH EXTENDING NORTHEAST THROUGH NORTHWEST WI. FAIRLY
STRONG ISENTROPIC LIFT AND MOISTURE TRANSPORT IN THE 850-700MB LAYER
WAS FUELING A 100 MILE WIDE BAND OF SHOWER/THUNDERSTORMS FROM
WESTERN UPPER MI THROUGH WESTERN WI/SOUTHEAST MN AND NORTHEAST IA.
ISOLATED POCKETS OF HEAVY RAIN NOTED WITH DODGE CENTER MN REPORTING
0.90 INCHES AS PRECIPITABLE WATER VALUES ARE NOW IN THE 1.3-1.5 INCH
RANGE. OTHERWISE...TEMPERATURES ACROSS THE AREA AS OF 3 AM WERE
RELATIVELY MILD IN THE 50S TO MIDDLE 60S.
FOR TODAY...THIS MID-LEVEL WAVE WILL PUSH OFF TO THE EAST WHILE
LEAVING A SURFACE TROUGH/QUASI-STATIONARY FRONT IN PLACE ACROSS
CENTRAL WISCONSIN...BASICALLY ALONG THE I-90 CORRIDOR. RAP AND NAM
SHOWING 850MB MOISTURE TRANSPORT WANING THIS MORNING AS THE
MID-LEVEL WAVE PUSHES EAST OF THE AREA. THIS WILL CAUSE A LULL IN
SHOWER AND THUNDERSTORM ACTIVITY BEFORE NOSE OF MOISTURE TRANSPORT
HEADS INTO THE AREA LATER THIS AFTERNOON. THIS IS IN RESPONSE TO
DEEPENING MID-LEVEL TROUGH AND SURFACE CYCLOGENESIS OVER THE
COLORADO HIGH PLAINS. INCREASING 850MB MOISTURE TRANSPORT AND
ISENTROPIC LIFT OVER THE QUASI-STATIONARY FRONT/WARM FRONT IN PLACE
WILL LEAD TO REGENERATION OF SHOWERS AND THUNDERSTORMS.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TONIGHT AS MOISTURE
TRANSPORT/ISENTROPIC LIFT CONTINUE OVER THE QUASI-STATIONARY FRONT.
CONCERN IS ELEVATED A BIT ON HEAVY RAIN POTENTIAL AS PRECIPITABLE
WATER VALUES CONTINUE TO INCREASE TO AROUND 1.5-1.7 INCHES WHICH IS
AROUND 200 PERCENT ABOVE NORMAL FOR THIS TIME OF YEAR. RIGHT
NOW...LOOKING AT WIDESPREAD 1/2 TO 3/4 INCH RAINFALL AMOUNTS ON TOP
OF WHAT FALLS TODAY...BUT COULD BE LOCALLY HIGHER AMOUNTS. 3-HR
FLASH FLOOD GUIDANCE OF 2-4 INCHES WOULD DICTATE A LOWER PROBABILITY
OF FLASH FLOODING. HOWEVER...FALLING LEAVES/LEAVE LITTER AND
POTENTIAL FOR DRAINAGE PROBLEMS...WILL LIKELY LEAD TO SOME LOCALIZED
PONDING OF WATER. WILL HAVE TO KEEP AN EYE ON THIS. OTHERWISE...NO
SEVERE WEATHER IS EXPECTED THROUGH TONIGHT AS 0-6KM BULK SHEAR NOT
VERY IMPRESSIVE.
TEMPERATURE-WISE...PLAN ON HIGHS IN 65-70 DEGREE RANGE ACROSS NORTH
CENTRAL WI...TO THE UPPER 70S/NEAR 80 ACROSS PORTIONS OF NORTHEAST
IA INTO FAR SOUTHWEST WI.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU OCT 3 2013
STILL LOOKING AT A SEVERE THREAT LATER FRIDAY AFTERNOON INTO FRIDAY
NIGHT AS MODEL CONSENSUS SHOWING THE POTENT LOW PRESSURE SYSTEM
MOVING OUT OF THE CENTRAL PLAINS INTO SOUTHWEST MN. SEVERE THREAT IS
TIED ALONG AND NORTH OF THE QUASI-STATIONARY FRONT AS 0-1KM ML
MUCAPE INCREASES INTO THE 2000-3000J/KG RANGE WITH 0-3KM BULK SHEAR
IN THE 30-40KT RANGE BY 21Z FRIDAY. LOOKS LIKE THE MAIN THREAT WOULD
BE LARGE HAIL WITH ELEVATED SUPERCELLS...BUT COULD BE A TORNADO
THREAT AS WELL ALONG THE BOUNDARY IF SUPERCELLS GET ROOTED IN THE
BOUNDARY LAYER. OTHERWISE...PLAN ON HIGHS IN THE UPPER 60S TO MIDDLE
70S NORTH OF I-94...TO THE UPPER 70S/NEAR 80 SOUTH OF I-90.
COULD SEE AN INCREASING THREAT FOR LOCALIZED FLOODING FRIDAY NIGHT
AS WELL WITH STRONGER MOISTURE TRANSPORT AND THREAT FOR VERY HEAVY
RAINFALL RATES.
SEVERE THREAT LOOKS LIKE IT COULD EXTEND INTO SATURDAY AS WELL TIED
TO THE COLD FRONTAL PASSAGE COUPLED WITH UPPER LEVEL DIFLUENCE.
LOOK FOR INCREASING SOUTHWEST WINDS IN THE AFTERNOON WITH THE
FRONTAL PASSAGE. EXPECT HIGHS IN THE 60S TO LOWER 70S.
LINGERING SCATTERED SHOWERS ARE STILL ANTICIPATED SATURDAY NIGHT
INTO SUNDAY TIED TO THE MID-LEVEL LOW MOVING ACROSS THE REGION.
TEMPERATURES WILL BE ON A DOWNGLIDE AS WELL WITH LOWS SATURDAY NIGHT
DIPPING DOWN INTO THE 40S AND HIGHS ON SUNDAY ONLY IN THE LOW TO
MIDDLE 50S.
ECMWF AND GFS STILL DIVERGE A BIT FOR THE SUNDAY NIGHT/MONDAY TIME
FRAME. THE ECMWF MUCH SLOWER WITH THE CLOSED MID-LEVEL LOW LIFTING
OUT OF THE AREA. THE GFS HAS THE LOW FILLING AND RAPIDLY LIFTING
NORTHEAST INTO EASTERN ONTARIO CANADA. TOOK A MODEL CONSENSUS FOR
NOW WHICH HAS US DRY SUNDAY NIGHT/MONDAY. LOOK FOR CHILLY LOWS
SUNDAY NIGHT IN THE UPPER 30S WITH HIGHS ON MONDAY REBOUNDING A BIT
INTO THE UPPER 50S TO MIDDLE 60S.
FOR TUESDAY INTO WEDNESDAY...THE GFS AND ECMWF COME BACK INTO BETTER
AGREEMENT WITH AN AMPLIFYING MID-LEVEL RIDGE OVER THE AREA. AS A
RESULT...LOOKS DRY WITH TEMPERATURES WARMING WELL INTO THE 60S ON
TUESDAY AND INTO THE LOWER 70S ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM CDT THU OCT 3 2013
SOUTHWEST FLOW AHEAD OF LARGE WESTERN UPPER TROUGH CONTINUES TO
PRODUCE ROUNDS OF CONVECTION WITH STRONG LOW LEVEL MOISTURE
TRANSPORT. TIMING OF EACH CONVECTIVE ELEMENT TROUBLESOME BUT
GENERALLY EXPECT A QUIET PERIOD AFTER CURRENT BAND OF STORMS
CONTINUES TO ADVECT NORTHEAST. AS LOW LEVEL JET INCREASES AGAIN THIS
EVENING...ADDITIONAL CONVECTION EXPECTED TO FIRE WHICH AGAIN COULD
IMPACT AVIATION SITES. DEPENDING ON MOVEMENT OF THAT COULD SEE A
PERIOD OF IFR TO LIFR UNTIL DAYTIME FRIDAY WHEN VFR SHOULD AGAIN
PREVAIL LEADING UP TO LATER DAY STORMS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....SHEA
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1041 AM CDT THU OCT 3 2013
.UPDATE...COMPLEX FORECAST NOW THROUGH SATURDAY. VIS SAT SHOWS A
HOLE IN THE CLOUD SHIELD ACROSS/NEAR DANE-COLUMBIA-DODGE COUNTIES
THAT IS STEADILY FILLING IN WITH CLOUDS UPSTREAM. SFC OBS IN EXTREME
SOUTHERN WISCONSIN STILL REPORTING AREAS OF FOG WITH VIS DOWN TO 1
SM AND LESS AT A FEW SITES. PATCHY DENSE FOG CANT BE RULED OUT
GIVEN LESS THAN A QUARTER MILE REPORTED AT KEFT. FOG EXPECTED TO
STEADILY IMPROVE/LIFT IN THE NEXT 1-2 HOURS...ESPECIALLY WITH RAIN
UPSTREAM COMING IN. WET CONDITIONS OTHERWISE CAN BE EXPECTED TODAY.
RADAR SHOWS LARGE LINE OF SHOWERS AND THUNDERSTORMS STRETCHING FROM
TO DUBUQUE IA TO EVANSTON IL. THIS ACTIVITY WILL CONTINUE TO MOVE
NORTHEAST AND THROUGH THE CWA. FARTHER UPSTREAM ARE ADDITIONAL
ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS TO COMPLICATE MATTERS.
HI-RES MODELS AND SPC SSEO GENERALLY HIGHLIGHT THE BEST CHANCE FOR
WX/POPS AFTER 18Z AND THEN INTO THE EVENING. THIS MATCHES THE
CURRENT FORECAST WELL. CAVEAT THOUGH IS THEY ARE NOT HANDLING THE
ONGOING CONVECTION THAT WELL. MUCH OF THE CONVECTION IN THE DVN CWA
ISNT BEING CAPTURED/RESOLVED. SO NOT MUCH CONFIDENCE IS PRESENT IN
THE HRRR AND LOCAL WRF FLAVOR...AT LEAST EARLY ON IN THEIR
SOLUTIONS. OTHERWISE...THE OVERALL CONCEPTUAL MODEL/CURRENT THINKING
HASNT CHANGED MUCH. WARM FRONT WILL MOVE NORTHWARD THROUGH SOUTHERN
WISCONSIN IN THE EARLY-MID AFTERNOON AND SHOWERS/THUNDERSTORMS ARE
EXPECTED THIS AFTERNOON-EVENING. GIVEN THE ONGOING CONVECTION AND
THE INGREDIENTS IN PLACE LATER ON...MODERATE ML AND MU
CAPE...LOW-LEVEL MOISTURE...AROUND 30 KTS 0-6 KM DEEP LAYER
SHEAR...TRAVERSING S/W TROUGH LATER ON THATS PRESENTLY IN CENTRAL
IA...WARM FRONT BOUNDARY IN THE VICINITY AND ANY RESIDUAL
BOUNDARIES...HAVE KEPT THE CURRENT WX/POPS FORECAST AS IS EXCEPT TO
REFLECT LATEST RADAR TRENDS IN THE NEXT 2-3 HOURS.
&&
.AVIATION/18Z TAFS/...THERE IS QUITE THE MIX OF CONDITIONS ACROSS
SOUTHERN WISCONSIN THIS MORNING...RANGING FROM MOSTLY SUNNY TO 1/4
MI VISIBILITY. OVERALL...THERE HAS BEEN A SLOW IMPROVEMENT IN
CONDITIONS AND THIS SHOULD CONTINUE INTO EARLY AFTERNOON. SOME
LOCATIONS MAY HANG ONTO MVFR OR IFR CONDITIONS THROUGH MUCH OF THE
DAY THOUGH BASED ON LATEST RAP SOUNDINGS.
A LINE OF SHOWERS AND STORMS IS CURRENTLY HEADING INTO SOUTHERN
WISCONSIN FROM THE SOUTHWEST AND WILL REACH AREAS FROM MADISON TO
RACINE BY 17Z IF IT HOLDS TOGETHER. MODELS ARE REALLY STRUGGLING
WITH THE CURRENT CONVECTION...SO FORECASTING BASED ON RADAR TRENDS
FOR THE TIME.
ADDITIONAL ROUNDS OF SHOWERS AND STORMS ARE EXPECTED THIS EVENING
THROUGH TOMORROW AS A WARM FRONT SLOWLY LIFTS NORTH THROUGH THE
FORECAST AREA. LOW CIGS AND VSBYS WILL CONTINUE TO BE POSSIBLE AT
TIMES UNTIL THE FRONT GETS NORTH OF THE FORECAST AREA. SOME MODELS
INDICATING THIS MAY NOT HAPPEN THROUGH THE DAY TOMORROW...SO NOT A
TON OF CONFIDENCE IN CONDITIONS THROUGH SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 339 AM CDT THU OCT 3 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
THE SURFACE MAP EARLY THIS MORNING SHOWS AN INVERTED TROF STRETCHING
FROM WEST CENTRAL WISCONSIN BACK ACROSS SOUTHWEST MN TO EASTERN NEB
AND FINALLY TO THE PARENT LOW OVER WESTERN KS. THIS PATTERN WILL
CHANGE LITTLE OVER THE NEXT 24-36HRS. THERE IS A WARM FRONT
STRETCHING FROM A SECONDARY LOW CENTER OVER SOUTHWEST MN THAT
EXTENDS ACROSS NORTHEAST IA THRU NORTHERN IL. THIS WARM FRONT
SEPARATES SOME VERY MOIST AIR TO THE SOUTH /MID 60 DEWPOINTS/ FROM
THE MUCH DRIER AIRMASS CURRENTLY OVER THE FORECAST AREA. ALL OF THE
CONVECTION THUS FAR HAS BEEN ALONG AND JUST BEHIND THE INVERTED
TROF. HOWEVER...BACK ACROSS NORTHEAST IA/SW WI...WE ARE SEEING AN
INCREASE IN CONVECTION EARLY THIS MORNING AS THE BETTER LOW LEVEL
JET OVER THAT AREA INTERACTS WITH THE ADVANCING WARM FRONT AND THE
REMAINS OF A COLD POOL/OUTFLOW FROM CONVECTION ACROSS SOUTHEAST MN.
THE WARM FRONT IS EXPECTED TO MOVE QUICKLY NORTH ACROSS THE SOUTHERN
WISCONSIN TODAY...ESPECIALLY AFTER SUNRISE. IT SHOULD ACTUALLY LEAP
NORTH AS WE MIX OUT THE LOW LEVEL INVERSION THAT WAS SET UP EARLIER
LAST EVENING. THE H8 WARM FRONT IS WELL NORTH BY NOW.
GIVEN THAT WE WILL HAVE THE WARM FRONT IN THE VCNTY TODAY...ELEVATED
DEWPOINTS...AND THERE IS A DECENT MID LEVEL TROF COMING IN THIS
AFTERNOON...MOST OF THE GUIDANCE IS SUGGESTING THE BEST POPS WILL BE
THIS AFTERNOON INTO THIS EVENING. AT THIS TIME...IT LOOKS LIKE MUCH
OF THE AREA THIS MORNING WILL BE QUIET EXCEPT FOR AREAS NORTHWEST OF
MADISON WHERE THE CURRENT INCREASE IN ACTIVITY JUST MENTIONED WILL
LIKELY CLIP THAT AREA. AS THE SHORT WAVE EXITS...IT APPEARS WE WILL
SEE A DECREASE IN ACTIVITY LATER THIS EVENING INTO THE REMAINING
OVERNIGHT HOURS. THE EXCEPTION MIGHT BE ACROSS OUR NORTHERN TIER
COUNTIES WHERE THE LINGERING PROXIMITY TO THE WARM FRONT COULD MAKE
CONVECTION A HIGHER PROBABILITY.
PRECIPITABLE WATER VALUES CLIMB TO ABOUT 1.5 INCHES WHICH...AS
MENTIONED IN THE PREV DISCUSSION...IS 2SD ABOVE NORMAL...GETTING
CLOSE TO THE 99TH PERCENTILE FOR WHAT IS NORMAL. SO...HEAVY RAIN
STILL A THREAT.
THIS IS A COMPLICATED SCENARIO LEADING UP TO THE EVENTUAL PASSAGE OF
THE INTENSE LOW ON SATURDAY...SO EXPECT PLENTY OF VARIABILITY GOING
FORWARD. ALSO...CONVECTION HAS A WAY OF REDEFINING/CHANGING THE
EVOLUTION OF EVERYTHING ELSE GOING FORWARD.
FRIDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE CLOSED 500MB UPPER LOW WILL DEEPEN AS IT MOVES INTO NE/SD BY
FRIDAY NIGHT. THE SURFACE LOW WILL MOVE FROM NE/KS TO MN/IA AS IT
STRENGTHENS. THE BOUNDARY THAT USED TO BE THE WARM FRONT WILL REMAIN
STATIONED OVER CENTRAL/NORTHERN WI FRIDAY AND FRIDAY NIGHT. TRIMMED
DOWN PRECIP CHANCES NEAR THE IL BORDER TOWARD THE WARM SECTOR.
SHORTWAVE ENERGY...UPPER DIVERGENCE WITH A COUPLED JET...NOSE OF THE
LOW LEVEL JET AND 700MB OMEGA WILL COME TOGETHER OVER SOUTHWEST WI
LATE FRIDAY AFTERNOON/EARLY FRIDAY EVENING DURING PEAK HEATING NEAR
THIS BOUNDARY. THIS IS THE AREA WITH HIGHEST CAPE /GREATER THAN 2000
J/KG/ AND BULK SHEAR /30-40 KTS/. CAPE AND SHEAR ARE SLIGHTLY LOWER
OVER SOUTH CENTRAL WI...BUT SUFFICIENT TO SUPPORT STRONG STORMS WITH
ISOLATED SEVERE POSSIBLE...AND ALSO TO SUSTAIN ANY SEVERE STORMS
THAT COULD DEVELOP TO OUR WEST. SPC DAY 2 SLIGHT RISK INCLUDES ALL
BUT SOUTHEAST WI...WITH THE HATCHED AREA /SIGNIFICANT SEVERE RISK/
OVER SOUTHEAST WI JUST WEST OF THE MKX FORECAST AREA.
HIGH PRECIPITABLE WATER VALUES AROUND 1.5 INCHES OVER WI WITH A
PERSISTENT SOUTHWESTERLY LOW LEVEL JET /LLJ/ COULD LEAD TO TRAINING
THUNDERSTORMS AND HEAVY RAIN.
THE SURFACE LOW WILL BEGIN TO OCCLUDE ON SATURDAY AND THE UPPER
LEVEL SYSTEM WILL SLOW DOWN. MOST MODELS ASIDE FROM THE NAM CONTINUE
TO SHOW A SLOWER FRONTAL PASSAGE THROUGH WI. THE WEATHER PREDICTION
CENTER PREFERS A 00Z GFS/00Z CANADIAN MODEL BLEND FOR THIS SYSTEM.
SHOWERS AND THUNDERSTORMS WILL BE LIKELY JUST AHEAD OF THE COLD
FRONT. GIVEN TIMING UNCERTAINTY...SPC REFRAINED FROM ISSUING A
SLIGHT RISK FOR DAY 3 FOR NOW...BUT MENTIONED THE POTENTIAL FOR
THUNDERSTORMS DEVELOPING INTO A SQUALL LINE WITH THE FRONT SATURDAY
AFTERNOON AND LEADING TO A DAMAGING WIND THREAT.
LONG TERM...
SUNDAY...FORECAST CONFIDENCE MEDIUM.
THE RAIN AND ISOLATED THUNDER COULD CONTINUE INTO SATURDAY EVENING
IF THE SLOW 00Z ECMWF PANS OUT. LOOK FOR PRECIP TO END SATURDAY
NIGHT. SUNDAY WILL BE A RAW DAY WITH HIGHS IN THE 50S AND GUSTY WEST
WINDS WITH CLOUDS AND LIGHT RAIN SHOWERS DUE TO LOW LEVEL
INSTABILITY WITH THE COLD AIR WRAPPED INTO THE MID LEVELS.
MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM.
SHOWERS COULD LINGER THROUGH MONDAY WITH THE SLOWER ECMWF SOLUTION.
EITHER WAY...UPPER LEVEL TROUGH WILL KEEP TEMPS COOL FOR THE DAY.
A MID LEVEL RIDGE WILL TAKE OVER ON TUESDAY. WARM AIR AND SUNSHINE
WILL RETURN TO WI FOR TUESDAY AND WEDNESDAY...WITH HIGHS BACK INTO
THE 70S.
ANOTHER UPPER TROUGH WILL DIG INTO THE INTERMOUNTAIN WEST MID WEEK
AND SHIFT INTO THE GREAT LAKES REGION LATE IN THE WEEK.
AVIATION/12Z TAFS/...
MVFR CONDITIONS ARE OVERSPREADING THE AREA THIS MORNING AS A WARM
FRONT APPROACHES...AND THIS LOWER CONDITIONS WILL LIKELY BE AROUND
THROUGH MUCH OF THE TAF PERIOD. WE SHOULD SEE AN INCREASE IN SHOWERS
AND STORMS THIS AFTERNOON...WITH THE MORNING LOOKING RATHER QUIET.
THIS INCREASE IN ACTIVITY IS MAINLY DUE TO THE ARRIVAL OF A MID
LEVEL SHORT WAVE THAT WILL INTERACT WITH THE SFC WARM FRONT LIKELY
TO BE HOVERING OVER SOUTHERN INTO CENTRAL WISCONSIN. AS THAT SHORT
WAVE EXITS TO THE NORTHEAST THIS EVENING...WE SHOULD SEE A GENERAL
DECREASE IN SHOWERS/STORMS LATER IN THE EVENING CONTINUING THROUGH
THE REMAINDER OF THE NIGHT. MORE AND STRONGER STORMS ARE THEN
EXPECTED ON FRIDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/DDV
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
FRIDAY THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
652 AM CDT THU OCT 3 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 345 AM CDT THU OCT 3 2013
MAIN CONCERN IS FOCUSED ON POTENT STORM SYSTEM AFFECTING THE AREA
TODAY AND INTO THE WEEKEND.
WATER VAPOR AND RAP 500MB ANALYSIS SHOWING A WEAK MID-LEVEL
SHORTWAVE EXTENDING FROM WESTERN MN INTO EASTERN NEB. AT THE
SURFACE...A WEAK SURFACE 1009MB LOW WAS ANALYZED JUST EAST OF KFSD
WITH A TROUGH EXTENDING NORTHEAST THROUGH NORTHWEST WI. FAIRLY STRONG
ISENTROPIC LIFT AND MOISTURE TRANSPORT IN THE 850-700MB LAYER WAS
FUELING A 100 MILE WIDE BAND OF SHOWER/THUNDERSTORMS FROM WESTERN
UPPER MI THROUGH WESTERN WI/SOUTHEAST MN AND NORTHEAST IA. ISOLATED
POCKETS OF HEAVY RAIN NOTED WITH DODGE CENTER MN REPORTING 0.90
INCHES AS PRECIPITABLE WATER VALUES ARE NOW IN THE 1.3-1.5 INCH
RANGE. OTHERWISE...TEMPERATURES ACROSS THE AREA AS OF 3 AM WERE
RELATIVELY MILD IN THE 50S TO MIDDLE 60S.
FOR TODAY...THIS MID-LEVEL WAVE WILL PUSH OFF TO THE EAST WHILE
LEAVING A SURFACE TROUGH/QUASI-STATIONARY FRONT IN PLACE ACROSS
CENTRAL WISCONSIN...BASICALLY ALONG THE I-90 CORRIDOR. RAP AND NAM
SHOWING 850MB MOISTURE TRANSPORT WANING THIS MORNING AS THE
MID-LEVEL WAVE PUSHES EAST OF THE AREA. THIS WILL CAUSE A LULL IN
SHOWER AND THUNDERSTORM ACTIVITY BEFORE NOSE OF MOISTURE TRANSPORT
HEADS INTO THE AREA LATER THIS AFTERNOON. THIS IS IN RESPONSE TO
DEEPENING MID-LEVEL TROUGH AND SURFACE CYCLOGENESIS OVER THE
COLORADO HIGH PLAINS. INCREASING 850MB MOISTURE TRANSPORT AND
ISENTROPIC LIFT OVER THE QUASI-STATIONARY FRONT/WARM FRONT IN PLACE
WILL LEAD TO REGENERATION OF SHOWERS AND THUNDERSTORMS.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TONIGHT AS MOISTURE
TRANSPORT/ISENTROPIC LIFT CONTINUE OVER THE QUASI-STATIONARY FRONT.
CONCERN IS ELEVATED A BIT ON HEAVY RAIN POTENTIAL AS PRECIPITABLE
WATER VALUES CONTINUE TO INCREASE TO AROUND 1.5-1.7 INCHES WHICH IS
AROUND 200 PERCENT ABOVE NORMAL FOR THIS TIME OF YEAR. RIGHT
NOW...LOOKING AT WIDESPREAD 1/2 TO 3/4 INCH RAINFALL AMOUNTS ON TOP
OF WHAT FALLS TODAY...BUT COULD BE LOCALLY HIGHER AMOUNTS. 3-HR
FLASH FLOOD GUIDANCE OF 2-4 INCHES WOULD DICTATE A LOWER PROBABILITY
OF FLASH FLOODING. HOWEVER...FALLING LEAVES/LEAVE LITTER AND
POTENTIAL FOR DRAINAGE PROBLEMS...WILL LIKELY LEAD TO SOME LOCALIZED
PONDING OF WATER. WILL HAVE TO KEEP AN EYE ON THIS. OTHERWISE...NO
SEVERE WEATHER IS EXPECTED THROUGH TONIGHT AS 0-6KM BULK SHEAR NOT
VERY IMPRESSIVE.
TEMPERATURE-WISE...PLAN ON HIGHS IN 65-70 DEGREE RANGE ACROSS NORTH
CENTRAL WI...TO THE UPPER 70S/NEAR 80 ACROSS PORTIONS OF NORTHEAST
IA INTO FAR SOUTHWEST WI.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU OCT 3 2013
STILL LOOKING AT A SEVERE THREAT LATER FRIDAY AFTERNOON INTO FRIDAY
NIGHT AS MODEL CONSENSUS SHOWING THE POTENT LOW PRESSURE SYSTEM
MOVING OUT OF THE CENTRAL PLAINS INTO SOUTHWEST MN. SEVERE THREAT IS
TIED ALONG AND NORTH OF THE QUASI-STATIONARY FRONT AS 0-1KM ML
MUCAPE INCREASES INTO THE 2000-3000J/KG RANGE WITH 0-3KM BULK SHEAR
IN THE 30-40KT RANGE BY 21Z FRIDAY. LOOKS LIKE THE MAIN THREAT WOULD BE
LARGE HAIL WITH ELEVATED SUPERCELLS...BUT COULD BE A TORNADO THREAT
AS WELL ALONG THE BOUNDARY IF SUPERCELLS GET ROOTED IN THE BOUNDARY
LAYER. OTHERWISE...PLAN ON HIGHS IN THE UPPER 60S TO MIDDLE 70S NORTH
OF I-94...TO THE UPPER 70S/NEAR 80 SOUTH OF I-90.
COULD SEE AN INCREASING THREAT FOR LOCALIZED FLOODING FRIDAY NIGHT
AS WELL WITH STRONGER MOISTURE TRANSPORT AND THREAT FOR VERY HEAVY
RAINFALL RATES.
SEVERE THREAT LOOKS LIKE IT COULD EXTEND INTO SATURDAY AS WELL TIED
TO THE COLD FRONTAL PASSAGE COUPLED WITH UPPER LEVEL DIFLUENCE.
LOOK FOR INCREASING SOUTHWEST WINDS IN THE AFTERNOON WITH THE
FRONTAL PASSAGE. EXPECT HIGHS IN THE 60S TO LOWER 70S.
LINGERING SCATTERED SHOWERS ARE STILL ANTICIPATED SATURDAY NIGHT
INTO SUNDAY TIED TO THE MID-LEVEL LOW MOVING ACROSS THE REGION.
TEMPERATURES WILL BE ON A DOWNGLIDE AS WELL WITH LOWS SATURDAY NIGHT
DIPPING DOWN INTO THE 40S AND HIGHS ON SUNDAY ONLY IN THE LOW TO
MIDDLE 50S.
ECMWF AND GFS STILL DIVERGE A BIT FOR THE SUNDAY NIGHT/MONDAY TIME
FRAME. THE ECMWF MUCH SLOWER WITH THE CLOSED MID-LEVEL LOW LIFTING
OUT OF THE AREA. THE GFS HAS THE LOW FILLING AND RAPIDLY LIFTING
NORTHEAST INTO EASTERN ONTARIO CANADA. TOOK A MODEL CONSENSUS FOR NOW
WHICH HAS US DRY SUNDAY NIGHT/MONDAY. LOOK FOR CHILLY LOWS SUNDAY
NIGHT IN THE UPPER 30S WITH HIGHS ON MONDAY REBOUNDING A BIT INTO THE
UPPER 50S TO MIDDLE 60S.
FOR TUESDAY INTO WEDNESDAY...THE GFS AND ECMWF COME BACK INTO BETTER
AGREEMENT WITH AN AMPLIFYING MID-LEVEL RIDGE OVER THE AREA. AS A
RESULT...LOOKS DRY WITH TEMPERATURES WARMING WELL INTO THE 60S ON
TUESDAY AND INTO THE LOWER 70S ON WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 652 AM CDT THU OCT 3 2013
A DIFFICULT FORECAST WITH UNCERTAINTY ON TIMING ROUNDS OF SHOWERS
AND THUNDERSTORMS...WHICH COULD GREATLY AFFECT CEILINGS AND
VISIBILITIES AS WELL.
AN IFR DECK HAS DEVELOPED OVER LSE...PRODUCED BY RAIN THAT WENT
THROUGH EARLIER IN THE NIGHT. HARD TO SAY HOW LONG IT IS GOING TO
LAST AS LSE IS THE ONLY SITE IN THE MISSISSIPPI RIVER VALLEY WITH
AN IFR CEILING. FOR NOW ONLY INCLUDED THE DECK UNTIL 14Z...AND
WILL WATCH TRENDS TO SEE IF IT NEEDS TO BE EXTENDED.
MEANWHILE SCATTERED SHOWERS AND STORMS EXIST ACROSS NORTHERN IOWA
AND SOUTHERN MN. THESE WILL BE MOVING ACROSS RST THROUGH THE
MORNING...WITH SOME INDICATIONS THAT THEY MAY BECOME MORE NUMEROUS
AROUND RST BETWEEN 16-21Z. AT LSE...HARDER TO SAY. LIKELY THERE
ARE GOING TO BE SOME SHOWER AND THUNDERSTORM ACTIVITY AROUND
THROUGH THE DAY...BUT TOO MUCH UNCERTAINTY EXISTS TO INCLUDE
EITHER -SHRA/-TSRA. BETTER SHOT OF SHOWER AND THUNDERSTORM
ACTIVITY WILL OCCUR TONIGHT AS A SURGE OF MOISTURE COMES AT THE
TAF SITES ABOVE THE SURFACE. THUS...FOR 00-12Z...HAVE -SHRA AND
VCTS. THERE EASILY COULD BE BRIEF BREAKS IN THE ACTIVITY.
CEILINGS AT RST SHOULD DROP TO MVFR BY 16Z AS THE MORE NUMEROUS
SHOWER ACTIVITY MOVES IN. THESE CEILINGS WILL DROP EVEN MORE
TONIGHT WITH VISIBILITIES LIKELY DROPPING TO MVFR AS WELL DUE TO
MORE MOISTURE AND PRECIPITATION MOVING IN. AT LSE...EXPECTING
AFTER CEILINGS CLIMB TO VFR AROUND 14Z TO DROP DOWN TO MVFR AROUND
00Z. BOTH LSE AND RST COULD SEE BRIEF PERIODS OF IFR
CEILINGS/VISIBILITIES TONIGHT...ESPECIALLY AT RST...BUT CONFIDENCE
IS TOO LOW TO INCLUDE AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 AM CDT THU OCT 3 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 345 AM CDT THU OCT 3 2013
MAIN CONCERN IS FOCUSED ON POTENT STORM SYSTEM AFFECTING THE AREA
TODAY AND INTO THE WEEKEND.
WATER VAPOR AND RAP 500MB ANALYSIS SHOWING A WEAK MID-LEVEL
SHORTWAVE EXTENDING FROM WESTERN MN INTO EASTERN NEB. AT THE
SURFACE...A WEAK SURFACE 1009MB LOW WAS ANALYZED JUST EAST OF KFSD
WITH A TROUGH EXTENDING NORTHEAST THROUGH NORTHWEST WI. FAIRLY STRONG
ISENTROPIC LIFT AND MOISTURE TRANSPORT IN THE 850-700MB LAYER WAS
FUELING A 100 MILE WIDE BAND OF SHOWER/THUNDERSTORMS FROM WESTERN
UPPER MI THROUGH WESTERN WI/SOUTHEAST MN AND NORTHEAST IA. ISOLATED
POCKETS OF HEAVY RAIN NOTED WITH DODGE CENTER MN REPORTING 0.90
INCHES AS PRECIPITABLE WATER VALUES ARE NOW IN THE 1.3-1.5 INCH
RANGE. OTHERWISE...TEMPERATURES ACROSS THE AREA AS OF 3 AM WERE
RELATIVELY MILD IN THE 50S TO MIDDLE 60S.
FOR TODAY...THIS MID-LEVEL WAVE WILL PUSH OFF TO THE EAST WHILE
LEAVING A SURFACE TROUGH/QUASI-STATIONARY FRONT IN PLACE ACROSS
CENTRAL WISCONSIN...BASICALLY ALONG THE I-90 CORRIDOR. RAP AND NAM
SHOWING 850MB MOISTURE TRANSPORT WANING THIS MORNING AS THE
MID-LEVEL WAVE PUSHES EAST OF THE AREA. THIS WILL CAUSE A LULL IN
SHOWER AND THUNDERSTORM ACTIVITY BEFORE NOSE OF MOISTURE TRANSPORT
HEADS INTO THE AREA LATER THIS AFTERNOON. THIS IS IN RESPONSE TO
DEEPENING MID-LEVEL TROUGH AND SURFACE CYCLOGENESIS OVER THE
COLORADO HIGH PLAINS. INCREASING 850MB MOISTURE TRANSPORT AND
ISENTROPIC LIFT OVER THE QUASI-STATIONARY FRONT/WARM FRONT IN PLACE
WILL LEAD TO REGENERATION OF SHOWERS AND THUNDERSTORMS.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TONIGHT AS MOISTURE
TRANSPORT/ISENTROPIC LIFT CONTINUE OVER THE QUASI-STATIONARY FRONT.
CONCERN IS ELEVATED A BIT ON HEAVY RAIN POTENTIAL AS PRECIPITABLE
WATER VALUES CONTINUE TO INCREASE TO AROUND 1.5-1.7 INCHES WHICH IS
AROUND 200 PERCENT ABOVE NORMAL FOR THIS TIME OF YEAR. RIGHT
NOW...LOOKING AT WIDESPREAD 1/2 TO 3/4 INCH RAINFALL AMOUNTS ON TOP
OF WHAT FALLS TODAY...BUT COULD BE LOCALLY HIGHER AMOUNTS. 3-HR
FLASH FLOOD GUIDANCE OF 2-4 INCHES WOULD DICTATE A LOWER PROBABILITY
OF FLASH FLOODING. HOWEVER...FALLING LEAVES/LEAVE LITTER AND
POTENTIAL FOR DRAINAGE PROBLEMS...WILL LIKELY LEAD TO SOME LOCALIZED
PONDING OF WATER. WILL HAVE TO KEEP AN EYE ON THIS. OTHERWISE...NO
SEVERE WEATHER IS EXPECTED THROUGH TONIGHT AS 0-6KM BULK SHEAR NOT
VERY IMPRESSIVE.
TEMPERATURE-WISE...PLAN ON HIGHS IN 65-70 DEGREE RANGE ACROSS NORTH
CENTRAL WI...TO THE UPPER 70S/NEAR 80 ACROSS PORTIONS OF NORTHEAST
IA INTO FAR SOUTHWEST WI.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CDT THU OCT 3 2013
STILL LOOKING AT A SEVERE THREAT LATER FRIDAY AFTERNOON INTO FRIDAY
NIGHT AS MODEL CONSENSUS SHOWING THE POTENT LOW PRESSURE SYSTEM
MOVING OUT OF THE CENTRAL PLAINS INTO SOUTHWEST MN. SEVERE THREAT IS
TIED ALONG AND NORTH OF THE QUASI-STATIONARY FRONT AS 0-1KM ML
MUCAPE INCREASES INTO THE 2000-3000J/KG RANGE WITH 0-3KM BULK SHEAR
IN THE 30-40KT RANGE BY 21Z FRIDAY. LOOKS LIKE THE MAIN THREAT WOULD BE
LARGE HAIL WITH ELEVATED SUPERCELLS...BUT COULD BE A TORNADO THREAT
AS WELL ALONG THE BOUNDARY IF SUPERCELLS GET ROOTED IN THE BOUNDARY
LAYER. OTHERWISE...PLAN ON HIGHS IN THE UPPER 60S TO MIDDLE 70S NORTH
OF I-94...TO THE UPPER 70S/NEAR 80 SOUTH OF I-90.
COULD SEE AN INCREASING THREAT FOR LOCALIZED FLOODING FRIDAY NIGHT
AS WELL WITH STRONGER MOISTURE TRANSPORT AND THREAT FOR VERY HEAVY
RAINFALL RATES.
SEVERE THREAT LOOKS LIKE IT COULD EXTEND INTO SATURDAY AS WELL TIED
TO THE COLD FRONTAL PASSAGE COUPLED WITH UPPER LEVEL DIFLUENCE.
LOOK FOR INCREASING SOUTHWEST WINDS IN THE AFTERNOON WITH THE
FRONTAL PASSAGE. EXPECT HIGHS IN THE 60S TO LOWER 70S.
LINGERING SCATTERED SHOWERS ARE STILL ANTICIPATED SATURDAY NIGHT
INTO SUNDAY TIED TO THE MID-LEVEL LOW MOVING ACROSS THE REGION.
TEMPERATURES WILL BE ON A DOWNGLIDE AS WELL WITH LOWS SATURDAY NIGHT
DIPPING DOWN INTO THE 40S AND HIGHS ON SUNDAY ONLY IN THE LOW TO
MIDDLE 50S.
ECMWF AND GFS STILL DIVERGE A BIT FOR THE SUNDAY NIGHT/MONDAY TIME
FRAME. THE ECMWF MUCH SLOWER WITH THE CLOSED MID-LEVEL LOW LIFTING
OUT OF THE AREA. THE GFS HAS THE LOW FILLING AND RAPIDLY LIFTING
NORTHEAST INTO EASTERN ONTARIO CANADA. TOOK A MODEL CONSENSUS FOR NOW
WHICH HAS US DRY SUNDAY NIGHT/MONDAY. LOOK FOR CHILLY LOWS SUNDAY
NIGHT IN THE UPPER 30S WITH HIGHS ON MONDAY REBOUNDING A BIT INTO THE
UPPER 50S TO MIDDLE 60S.
FOR TUESDAY INTO WEDNESDAY...THE GFS AND ECMWF COME BACK INTO BETTER
AGREEMENT WITH AN AMPLIFYING MID-LEVEL RIDGE OVER THE AREA. AS A
RESULT...LOOKS DRY WITH TEMPERATURES WARMING WELL INTO THE 60S ON
TUESDAY AND INTO THE LOWER 70S ON WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1139 PM CDT WED OCT 2 2013
AREA OF CONVECTION CONTINUES TO MOVE PRIMARILY NORTHEAST WHILE
EDGING SLOWLY TOWARD KRST. EXPECTING THE LEADING EDGE OF THE RAIN
BAND TO BE NEAR THE AIRPORT BY 06Z SO WILL START WITH TAF WITH
SOME RAIN. HIGHER RETURNS BETWEEN KOWA AND KMKT SUGGEST THE
POTENTIAL FOR SOME THUNDER WITH CONDITIONS GOING DOWN TO IFR FOR A
WHILE AND HAVE INCLUDED THIS AS A POSSIBILITY THROUGH 09Z.
CONFIDENCE ON WHETHER THIS LINE WILL REACH KLSE IS MUCH LOWER AS
THE CURRENT MOVEMENT COULD TAKE IT PAST TO THE NORTH. HAVE THUS
OPTED TO REMAIN WITH SOME SHOWERS COMING IN OVERNIGHT WITH JUST A
VCTS UNTIL IT BECOMES CLEARER AS WHETHER THE LINE WILL HIT KLSE OR
NOT. BOTH THE 03.00Z NAM AND 03.02Z HRRR SHOW THIS AREA OF
CONVECTION LIFTING PAST BOTH SITES OVERNIGHT WITH THE LEAD SHORT
WAVE TROUGH AND HAVE MAINTAINED DROPPING BACK TO JUST VCSH LATE
TONIGHT. MORE CONVECTION THEN EXPECTED TO DEVELOP LATE THURSDAY
MORNING AS THE NEXT SHORT WAVE TROUGH STARTS TO IMPINGE ON THE
WARM FRONT THAT WILL BE OVER THE AREA. ENOUGH CAPE WILL BE PRESENT
FOR THUNDER AGAIN AND HAVE MAINTAINED CONTINUITY OF SHOWING MVFR
CONDITIONS. SOME UNCERTAINTY ON HOW LONG THIS SECOND ROUND WILL
PERSIST AS THE SHORT WAVE TROUGH WILL BE MOVING PAST BUT WITH THE
BOUNDARY STILL OVER THE AREA AND MOISTURE TRANSPORT INTO IT COULD
SEE SOME ACTIVITY WELL INTO THE EVENING. FOR NOW...DROPPED BACK TO
VCSH FOR THE LATE AFTERNOON AND EVENING...BUT CONFIDENCE IS VERY
LOW ON THIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT WED OCT 2 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 337 PM CDT WED OCT 2 2013
MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES
TONIGHT THROUGH THURSDAY NIGHT. FOCUS THEN TURNS TO SEVERE
THUNDERSTORM POTENTIAL FRIDAY INTO SATURDAY.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH DIGGING INTO THE WEST
COAST/SOUTHWEST CONUS. MEANWHILE...FLOW ALOFT OVER THE UPPER
MISSISSIPPI RIVER VALLEY WAS STARTING TO TURN SOUTHWEST. SEVERAL
EMBEDDED SHORTWAVES WERE NOTED OVER THE NORTHERN PLAINS AND CENTRAL
ROCKIES...TAKING AIM AT THE REGION TONIGHT INTO THURSDAY. SURFACE
OBSERVATIONS SHOWED SURFACE LOW PRESSURE OVER CENTRAL SOUTH
DAKOTA...EDGING EAST. A WARM FRONT EXTENDED FROM NORTH CENTRAL
NEBRASKA...SOUTHEAST THROUGH SOUTHERN IOWA INTO CENTRAL ILLINOIS.
THE SURFACE LOW/INVERTED TROUGH WILL PUSH INTO THE UPPER MISSISSIPPI
RIVER VALLEY REGION TONIGHT AND INTERACT WITH A SERIES OF SHORTWAVES
MOVING OVER THE AREA. SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER
NORTHWEST IOWA THROUGH SOUTHWEST AND CENTRAL MINNESOTA LATE THIS
AFTERNOON AND EVENING. THIS ACTIVITY WILL PUSH EAST IMPACTING
SOUTHEAST MINNESOTA AND PORTIONS OF NORTHEAST IOWA. THE SHOWERS AND
STORMS WILL ALSO MOVE INTO WEST CENTRAL INTO NORTH CENTRAL WISCONSIN
LATE TONIGHT INTO EARLY THURSDAY MORNING. THE BULK OF THE ACTIVITY
SHOULD STAY WEST OF THE MISSISSIPPI RIVER UNTIL AFTER SUNRISE ON
THURSDAY. SEVERE WEATHER IS NOT EXPECTED TONIGHT WITH VERY LITTLE
0-3KM MUCAPE TO WORK WITH...AROUND 300 J/KG...AND RATHER WEAK SHEAR
WITH 0-3KM BULK SHEAR VALUES OF 20 TO 30 KTS. A VERY MOIST AIRMASS
MOVES INTO THE REGION TONIGHT INTO THURSDAY WITH PRECIPITABLE WATER
VALUES CLIMBING TO AROUND 1.5 INCHES WHICH IS 230 PERCENT OF
NORMAL. WITH PRECIPITABLE WATER VALUES THIS HIGH...ANY
THUNDERSTORMS SHOULD BE EFFICIENT RAIN PRODUCERS. SHORTWAVES WILL
CONTINUE TO TRACK ACROSS THE AREA DURING THE DAY ON THURSDAY WITH
SHOWERS AND SCATTERED THUNDERSTORMS LIKELY. WHILE IT WON/T BE AN
ALL DAY RAIN...PLAN ON PERIODS OF SHOWERS AND THUNDERSTORMS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 337 PM CDT WED OCT 2 2013
THE UPPER TROUGH IS EXPECTED TO DIG INTO THE CENTRAL ROCKIES
THURSDAY NIGHT. MODEL SOLUTIONS THEN START TO DIVERGE FROM LATE
THURSDAY NIGHT INTO FRIDAY IN THE HANDLING OF THIS TROUGH. THE NAM
IS THE MOST AGGRESSIVE. IT EJECTS THE TROUGH OUT OF THE ROCKIES AND
INTO EASTERN SOUTH DAKOTA DURING THE DAY ON FRIDAY. THIS SOLUTION
WOULD LIFT A DEEPENING SURFACE LOW ACROSS EASTERN
NEBRASKA...NORTHWEST IOWA...INTO SOUTHWEST MINNESOTA. A WARM FRONT
WOULD LIFT NORTHWARD ACROSS THE FORECAST AREA AND BE THE FOCUS FOR
THE DEVELOPMENT OF SEVERE THUNDERSTORMS. THESE STORMS WOULD LIKELY
BE SUPERCELLS GIVEN 0-6 KM BULK SHEAR VALUES OF 45 TO 55 KTS AND
MLCAPE VALUES IN THE 1500 TO 2500 J/KG RANGE. THE SEVERE WEATHER
THREAT WOULD INCLUDE LARGE HAIL AND DAMAGING WINDS. A FEW
TORNADOES WOULD ALSO BE POSSIBLE WITH THE NAM SCENARIO...GIVEN 0-1
KM BULK SHEAR VALUES OF 25 TO 30 KTS AND MLLCL HEIGHT OF AROUND
1600 FT. TIMING FOR THIS SEVERE WEATHER THREAT WOULD BE LATE
FRIDAY AFTERNOON INTO FRIDAY NIGHT AND WOULD INCLUDE MUCH OF
NORTHEAST IOWA...SOUTHEAST MINNESOTA AND PORTIONS OF SOUTHWEST
WISCONSIN. AT THIS TIME...THE NAM IS THE OUTLIER...WITH THE ECMWF
AND GFS SHOWING SLOWER SOLUTIONS. THESE MODELS SHOW THE TROUGH
MOVING OUT OF THE ROCKIES AND INTO THE PLAINS FRIDAY NIGHT. THIS
WOULD BRING THE WARM FRONT AND SURFACE LOW INTO THE REGION LATE
FRIDAY NIGHT INTO EARLY SATURDAY MORNING. THERE COULD STILL BE A
SEVERE THREAT FRIDAY AFTERNOON OVER PORTIONS OF NORTHEAST IOWA AND
FAR SOUTHWEST WISCONSIN...BUT THE BETTER SUPPORT FOR SEVERE
WEATHER WILL BE OVER WESTERN IOWA. SHOWERS AND STORMS WILL
CONTINUE THROUGH THE NIGHT ON FRIDAY AS THE LOW MOVES IN. SOME OF
THE STORMS COULD PRODUCE HEAVY RAINFALL...SO WILL HAVE TO KEEP AN
EYE ON THE POTENTIAL FOR FLASH FLOODING. THE AREA CAN WITHSTAND A
FAIR AMOUNT OF RAINFALL...WITH 3 HOUR FLASH FLOOD GUIDANCE RUNNING
RIGHT AROUND 3 INCHES ACROSS MUCH OF THE FORECAST AREA. THE MAIN
CONCERN WILL BE RAINFALL RATES AND HOW MUCH RAINFALL IS RECEIVED
ON THURSDAY. THERE SURFACE LOW LIFTS THROUGH THE FORECAST AREA
DURING THE DAY ON THURSDAY. THERE IS THE POTENTIAL FOR ISOLATED
SEVERE STORMS ON SATURDAY AS THE LOW MOVES THROUGH. AGAIN...SHEAR
PROFILES COULD SUPPORT SUPERCELLS WITH 0-6KM BULK SHEAR VALUES OF
40 TO 50S KTS. MLCAPE LOOKS TO BE THE MAJOR LIMITING FACTOR WITH
VALUES HOVERING IN THE 600 TO 1000 J/KG RANGE. IF WE COULD GET
SOME SURFACE HEATING BEFORE THE LOW MOVES IN WE COULD SEE SOME
SURFACE BASED STORMS AND THE OUTSIDE CHANCE OF SEEING AN ISOLATED
TORNADO OVER SOUTHWEST WISCONSIN.
THE COLD FRONT CHARGES THROUGH THE FORECAST AREA SATURDAY AFTERNOON
INTO SATURDAY EVENING WITH TEMPERATURES FALLING BEHIND IT. THE
FORECAST AREA THEN LOOKS TO BE IN TH DRY SLOT SATURDAY NIGHT INTO
SUNDAY MORNING AS THE UPPER LOW TRACKS EAST ACROSS SOUTHERN SOUTH
DAKOTA/SOUTHERN MINNESOTA. SHOWERS WRAPPING AROUND THE BACK SIDE OF
THE LOW LOOK TO MOVE INTO THE AREA LATE SUNDAY MORNING INTO SUNDAY
AFTERNOON. THE LOW FINALLY EXITS THE REGION MONDAY AFTERNOON. PLAN
ON MAINLY QUIET WEATHER MONDAY NIGHT THROUGH TUESDAY NIGHT. ANOTHER
SYSTEM COULD IMPACT THE REGION LATE NEXT WEEK SO WE WILL HAVE TO
KEEP AN EYE ON THIS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1139 PM CDT WED OCT 2 2013
AREA OF CONVECTION CONTINUES TO MOVE PRIMARILY NORTHEAST WHILE
EDGING SLOWLY TOWARD KRST. EXPECTING THE LEADING EDGE OF THE RAIN
BAND TO BE NEAR THE AIRPORT BY 06Z SO WILL START WITH TAF WITH
SOME RAIN. HIGHER RETURNS BETWEEN KOWA AND KMKT SUGGEST THE
POTENTIAL FOR SOME THUNDER WITH CONDITIONS GOING DOWN TO IFR FOR A
WHILE AND HAVE INCLUDED THIS AS A POSSIBILITY THROUGH 09Z.
CONFIDENCE ON WHETHER THIS LINE WILL REACH KLSE IS MUCH LOWER AS
THE CURRENT MOVEMENT COULD TAKE IT PAST TO THE NORTH. HAVE THUS
OPTED TO REMAIN WITH SOME SHOWERS COMING IN OVERNIGHT WITH JUST A
VCTS UNTIL IT BECOMES CLEARER AS WHETHER THE LINE WILL HIT KLSE OR
NOT. BOTH THE 03.00Z NAM AND 03.02Z HRRR SHOW THIS AREA OF
CONVECTION LIFTING PAST BOTH SITES OVERNIGHT WITH THE LEAD SHORT
WAVE TROUGH AND HAVE MAINTAINED DROPPING BACK TO JUST VCSH LATE
TONIGHT. MORE CONVECTION THEN EXPECTED TO DEVELOP LATE THURSDAY
MORNING AS THE NEXT SHORT WAVE TROUGH STARTS TO IMPINGE ON THE
WARM FRONT THAT WILL BE OVER THE AREA. ENOUGH CAPE WILL BE PRESENT
FOR THUNDER AGAIN AND HAVE MAINTAINED CONTINUITY OF SHOWING MVFR
CONDITIONS. SOME UNCERTAINTY ON HOW LONG THIS SECOND ROUND WILL
PERSIST AS THE SHORT WAVE TROUGH WILL BE MOVING PAST BUT WITH THE
BOUNDARY STILL OVER THE AREA AND MOISTURE TRANSPORT INTO IT COULD
SEE SOME ACTIVITY WELL INTO THE EVENING. FOR NOW...DROPPED BACK TO
VCSH FOR THE LATE AFTERNOON AND EVENING...BUT CONFIDENCE IS VERY
LOW ON THIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1058 PM MDT WED OCT 2 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 251 PM MDT WED OCT 2 2013
THERE IS INCREASING CONFIDENCE FOR A MAJOR AUTUMN SNOW STORM
ACROSS THE FORECAST AREA...ESPECIALLY ACROSS MOST OF SOUTHEAST
WYOMING AND THE NORTHERN NEBRASKA PANHANDLE BEGINNING LATE THURSDAY
AND CONTINUING THROUGH LATE FRIDAY. CURRENT WATER VAPOR LOOP SHOWS
THIS STORM DIGGING SOUTH ALONG THE BRITISH COLUMBIA AND WASHINGTON
STATE COASTLINE TODAY. THIS POTENT UPPER LEVEL TROUGH WILL
CONTINUE DIGGING SOUTHEAST INTO NORTHERN NEVADA/IDAHO
TONIGHT...AND EVENTUALLY INTO UTAH BY THURSDAY. QUIET WEATHER WILL
CONTINUE TONIGHT ACROSS MOST OF THE AREA...ALTHOUGH CLOUDS WILL
CONTINUE TO INCREASE THIS EVENING AND THROUGH TONIGHT. THIS WILL
KEEP LOW TEMPERATURES FROM GETTING TOO COLD TONIGHT WITH LOWS IN
THE UPPER 30S TO UPPER 40S. THERE WILL BE A CHANCE OF RAIN SHOWER
ACTIVITY ACROSS THE FAR NORTHERN ZONES FROM NORTHERN CARBON COUNTY
EASTWARD TO NORTHWEST NEBRASKA...WITH SOME WET SNOW OVER THE
MOUNTAINS.
FOR THURSDAY AND THURSDAY NIGHT...CONDITIONS WILL CHANGE RAPIDLY
FROM WEST TO EAST AS THE 500MB UPPER LEVEL LOW BEGINS TO IMPACT
THE FORECAST AREA. WIDESPREAD RAINFALL WILL PUSH INTO CARBON AND
CONVERSE COUNTY WITH SNOW LEVELS LOWERING TO 8000 FEET AS THE MAIN
FRONT MOVES INTO CENTRAL WYOMING. FURTHER TO THE
EAST...THUNDERSTORMS AND HEAVY RAIN SHOWERS WILL DEVELOP AS LI/S
LOWER TO -3C TO -5C AND STRONG MID TO UPPER LEVEL ASCENT ENHANCE
CONVECTIVE POTENTIAL EAST OF THE LARAMIE RANGE. MODELS ALSO
INDICATE A WEAK SHORTWAVE DISTURBANCE MOVING NORTHEAST AHEAD OF
MAIN LOW...ENHANCING CONVECTIVE POTENTIAL. MAY SEE SOME DECENT
RAINFALL AMOUNTS OVER ONE INCH FROM THESE SHOWERS AND TSTORMS
BASED ON CURRENT MODEL RUNS. OTHERWISE...STEADY WIDESPREAD
RAINFALL WILL CONTINUE MOVING EAST INTO THE HIGH PLAINS OF
WYOMING AFTER MIDNIGHT WITH SNOW LEVELS LOWERING TO 5000-6000 FEET
BY SUNRISE...AND ALL SNOW IN THE MOUNTAINS.
WIDESPREAD MODERATE TO LOCALLY HEAVY SNOWFALL IS EXPECTED ON
FRIDAY. FOR SOUTHEAST WYOMING...FRIDAY MORNING THROUGH EARLY
FRIDAY AFTERNOON APPEARS TO BE THE WORST OF THE STORM WITH A QUICK
CHANGE OVER THE HEAVY SNOWFALL AND NORTH TO NORTHEAST WINDS
BECOMING STRONG. STRONG CONVERGENCE ALONG THE INTENSIFYING FRONT
AND 700MB LOW WILL RESULT IN OMEGA LIFT BETWEEN 20 TO 35
UB/S...ESPECIALLY EAST OF THE LARAMIE RANGE AIDED BY DEEP UPSLOPE
FLOW. WINDS MAY GUST AS HIGH AS 50 MPH AT TIMES WITH BLOWING AND
DRIFTING SNOW AS WELL AS POSSIBLE WHITE OUT CONDITIONS IN SOME
AREAS. SNOW ACCUMULATIONS WILL BE TRICKY...BUT GENERALLY EXPECTED
4 TO 8 INCHES WEST OF THE LARAMIE RANGE...8 TO 16 INCHES EAST OF
THE LARAMIE RANGE EXCLUDING THE LOWER NORTH PLATTE RIVER VALLEY
WHERE LESSER AMOUNTS ARE EXPECTED DUE TO HIGHER SNOW LEVELS
INITIALLY. CONCERNED ABOUT HIGHER AMOUNTS ACROSS A BROAD AREA
ALONG AND EAST OF THE LARAMIE RANGE...BUT DID NOT INCREASE SNOW
AMOUNTS QUITE THAT HIGH YET. ACROSS WESTERN NEBRASKA...MAINLY
EXPECT RAINFALL FRIDAY MORNING BUT RAIN WILL GRADUALLY CHANGE TO
SNOW AS THE FRONT MOVES EASTWARD DURING THE AFTERNOON. ADDED THE
NORTHERN PANHANDLE OF NEBRASKA TO THE WINTER STORM WATCH SINCE THE
COLD AIR WILL PUSH INTO THAT AREA SOONER COMPARED TO FURTHER
SOUTH. ACROSS THE SOUTHERN PANHANDLE...INCLUDING SIDNEY...WARMER
AIR WILL HANG ON UNTIL FRIDAY EVENING BASED ON CURRENT MODEL
TRENDS. ALTHOUGH A PERIOD OF SNOW IS EXPECTED...DO NOT EXPECT MUCH
ACCUMULATION WITH MOSTLY RAIN.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 251 PM MDT WED OCT 2 2013
THE STRONG UPPER LOW WILL SHIFT NORTHEAST INTO THE DAKOTAS ON FRIDAY
NIGHT AND SATURDAY. PLENTIFUL WRAPAROUND MOISTURE AND LINGERING QG
FORCING WITH THE UPPER LOW WILL COMBINE WITH MODERATE NW SFC WINDS
TO MAINTAIN A CHANCE FOR SNOW THROUGH FRIDAY NIGHT...ESPECIALLY OVER
THE NEBRASKA PANHANDLE. LIKELY TO SEE AN ADDITION 1 TO 3 INCHES IN
THE PANHANDLE...WITH THE HIGHER AMOUNTS IN THE NORTHERN COUNTIES. WINDS
SUSTAINED AT 10 TO 20 WITH HIGHER GUSTS WILL MAINTAIN BLOWING SNOW
OVERNIGHT ACROSS AREAS ALONG AND EAST OF THE LARAMIE RANGE...SO
HAZARDOUS CONDITIONS WILL CONTINUE ACROSS THIS AREA THROUGH EARLY
SATURDAY. EXTENDED THE WINTER STORM WATCH FOR THE NORTHERN PANHANDLE
THROUGH 6 AM MDT SATURDAY FOR THE COMBINATION OF WINDS AND LINGERING
MODERATE SNOWFALL. THIS INCLUDES SIOUX...DAWES AND BOX BUTTE
COUNTIES.
MUCH DRIER AIR WILL MOVE IN FROM THE NORTHWEST BEHIND THE SYSTEM AND
PRECIP WILL END FROM WEST TO EAST THROUGH EARLY SATURDAY MORNING.
BREEZY WESTERLY WINDS LOOK TO PERSIST THO ACROSS THE FORECAST AREA
AS SFC HIGH PRESSURE BUILDS IN FROM THE WEST. SO COULD SEE BLOWING
SNOW CONDITIONS PERSIST DEPENDING ON HOW MUCH SNOW REMAINS OR HAS
CRUSTED ON TOP DUE TO THE HEAVY/WET NATURE OF THE SNOW AND WINDS
OVERNIGHT. TEMPERATURES WILL QUICKLY REBOUND SATURDAY AND SUNDAY AS
HEIGHTS ALOFT RISE AND WESTERLY DOWNSLOPE WINDS ENHANCING WARMING.
UNDERCUT GUIDANCE A FEW DEGREES FOR SATURDAY DUE TO THE EXPECTED
SNOW PACK THO. WILL RETURN TO MORE OF THE ZONAL FLOW PATTERN MONDAY
AND TUESDAY...WITH MILD...BREEZY AND DRY CONDITIONS TO OCCUR THROUGH
THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 1052 PM MDT WED OCT 2 2013
EXPECT DETERIORATING CONDITIONS OVER THE NEXT 24 HOURS AS
UPSLOPING EASTERLY FLOW SETS UP EAST OF THE LARAMIE RANGE AND A
STRONG COLD FRONT APPROACHES FROM THE WEST. LATEST HRRR GUIDANCE
SHOWING LOW CEILINGS IN THE NEBRASKA PANHANDLE AS EARLY AS
13Z...PERSISTING THROUGH MUCH OF THE DAY. TIMING ON THE COLD FRONT
LOOKS TO BE MOVING THROUGH KRWL AROUND 21Z...KLAR...00Z...KCYS
AROUND 02Z TO 03Z AND THEN THE PANHANDLE AFTER 00Z. RAIN WILL
CHANGE OVER TO SNOW BEHIND THE FRONT AND PERSIST THROUGH MUCH OF
FRIDAY WITH IFR/LIFR CONDITIONS IN SNOW AND BLOWING SNOW.
&&
.FIRE WEATHER...
ISSUED AT 251 PM MDT WED OCT 2 2013
WITH A STRONG WINTER STORM APPROACHING THE AREA LATE THIS
WEEK...NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND DUE TO COLDER
TEMPERATURES...HIGH HUMIDITIES AND WIDESPREAD SNOW AND RAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
AFTERNOON FOR WYZ101-102-106>108-115>119.
WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON FOR WYZ103>105-109>114.
NE...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT
FOR NEZ002-003-095-096.
&&
$$
SHORT TERM...TJT
LONG TERM...RJM
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
434 PM EDT FRI OCT 4 2013
.SYNOPSIS...
ISSUED AT 434 PM EDT FRI OCT 4 2013
A WARM AND MOIST AIRMASS WILL REMAIN OVER THE REGION INTO THE
WEEKEND. PERIODIC SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS
EVENING THROUGH LATE SATURDAY NIGHT WHEN A COLD FRONT APPROACHES
THE AREA FROM THE WEST. WELL ABOVE NORMAL TEMPERATURES WILL
CONTINUE WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID 60S.
&&
.UPDATE...
ISSUED AT 113 PM EDT FRI OCT 4 2013
GRID UPDATE EARLY THIS AFTERNOON TO ACCOUNT FOR DEVELOPMENT OF SCT
SHOWERS AND THUNDERSTORMS. BREAKS IN CLOUD COVER LATE THIS
MORNING AND EARLY AFTERNOON HAVE ALLOWED FOR TEMPERATURES TO
QUICKLY WARM INTO THE UPPER 70S TO LOW 80S IN MOST LOCATIONS. SCT
SHOWERS POPPING UP AS CONVECTIVE TEMPS REACHED WITH SB CAPE VALUES
EXCEEDING 1000 J/KG. LATEST HRRR AND RAP RUNS HAVE CAPTURED THIS
DECENTLY AND SUSPECT THIS ACTIVITY WILL CONTINUE INTO THE EVENING
HOURS. THEREFORE HAVE ADDED SCT TSRA ACROSS ENTIRE AREA THRU 00Z.
ONLY MINOR CHANGES MADE TO TEMPS AND SKY COVER GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM EDT FRI OCT 4 2013
LEE CYCLOGENESIS IS NOW WELL UNDERWAY ACROSS THE CENTRAL PLAINS
AS 100+ KT JET ROUNDS THE BASE OF LONGWAVE TROUGH PRESENTLY OVER
THE ROCKIES. ASSOCIATED VORT MAX IS VERY IMPRESSIVE WITH A CLASSIC
TREBLE CLEF SIGNATURE DEVELOPING ON THE 1.5 PVU SURFACE
TODAY...AND THE MAIN PV LOBE EXTENDING THROUGH MOST OF THE
TROPOSPHERE. THIS STRONG PV ADVECTION WILL COMBINE WITH GOOD
DIFFLUENCE ALOFT AND SOME SEMBLANCE OF A COUPLED UPPER JET
STRUCTURE TO SUPPORT CONTINUED STRENGTHENING OF THE CENTRAL PLAINS
SURFACE LOW. WHAT THIS MEANS LOCALLY IS THAT SOUTHWEST
FLOW/THETA-E ADVECTION WILL PERSIST THROUGH THE SHORT TERM WITH A
LITANY OF CONVECTIVELY ENHANCED SHORTWAVES CONTINUING TO IMPACT
THE SOUTHERN GREAT LAKES. SURFACE WARM FRONT WILL REMAIN DRAPED
JUST TO OUR NORTH AND SUBTLE HEIGHT RISES DOWNSTREAM OF
APPROACHING TROUGH SHOULD KEEP THE BULK OF OUR AREA DRY TODAY AS
THE FOCUS OF CONVECTION REMAINS IN LOWER MICHIGAN. CONFIDENCE IN
THIS SCENARIO REMAINS LOW HOWEVER GIVEN WEAK/BROAD 300-305K
ISENTROPIC ASCENT AND VERY LITTLE CONVECTIVE INHIBITION ON NEWEST
NAM AND GFS BUFR SOUNDINGS. NOTHING IN THE LATEST RADAR IMAGERY OR
HI-RES GUIDANCE TO SUPPORT ALTERING DRY FORECAST AFTER REMAINING
SHOWERS EXIT AROUND 12Z...BUT WILL HAVE TO KEEP AN EYE ON THIS
THROUGHOUT THE DAY AS AN ISOLATED SHOWERS/STORM IS CERTAINLY NOT
OUTSIDE THE REALM OF POSSIBILITY. THIS WILL BE ESPECIALLY TRUE IN
OUR FAR NORTHERN COUNTIES...CLOSER TO THE SURFACE WARM FRONT AND
EXPECTED TRAIN OF W-E ORIENTED CONVECTIVE CLUSTERS. CONFIDENCE IN
HIGH TEMP FORECAST IS SIMILARLY LOW. ANY SUSTAINED BREAKS IN CLOUD
COVER COULD ALLOW HIGHS TO SURGE WELL INTO THE MID 80S GIVEN 850MB
TEMPS AROUND 16C. EXPECT THERE WILL STILL BE A FAIR AMOUNT OF
CLOUDS IN THE AFTERNOON THOUGH AND WILL MAINTAIN HIGHS IN THE LOW
TO MID 80S. LITTLE CHANGES DURING THE OVERNIGHT PERIOD AS WE
REMAIN IN A REGION OF BROAD WARM/MOIST AIR ADVECTION. LACK OF
CLEAR FORCING MECHANISM AT THIS POINT WARRANTS JUST A LOW CHANCE
OF POPS. LOWS WILL BE VERY MILD...LIKELY NOT DROPPING MUCH BELOW
THE UPPER 60S IN THIS VERY MOIST ENVIRONMENT. COULD ALSO BE A FEW
AREAS OF FOG OVERNIGHT GIVEN POOLING MOISTURE AND LIGHT SURFACE
WINDS BENEATH A STRENGTHENING INVERSION. MAV AND MET GUIDANCE BOTH
SUPPORT PERIODS OF FOG BUT WITH THE FRONT NORTH OF HERE AND VERY
LITTLE FOG THIS MORNING...WILL LEAVE OUT MENTION FOR NOW AND LET
LATER SHIFT MODIFY AS NECESSARY.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 342 AM EDT FRI OCT 4 2013
VRY INTENSE SW TROUGH AND ATTENDANT UPR JET STREAK CARVING OUT AN
IMPRESSIVE CYCLONE ACRS THE CNTRL ROCKIES THIS MORNING. SFC LOW
CNTRD OVR SE CO WILL LIFT NEWD AND OCCLUDE INTO SAT MORNING ACRS
SERN SD AND YIELD A SLW EWD EJECTION OF SFC OCCLUSION. BROAD/MOIST WARM
SECTOR WILL PERSIST EWD ACRS THE LAKES/OH VALLEY YET W/MINIMAL
BACKGROUND FOCUS. THUS KEPT W/A MINIMIZED LOWER BLENDED POP THROUGH
SAT AFTN. CONTD EWD PROGRESSION OF OCCLUDED FNT LT SAT NIGHT WILL
BRING ABT A PD OF SHRA/TSRA AND LIKELY LINGER ACRS ERN ZONES THROUGH
SUN AFTN. OTRWS STG NEG THETA-E ADVTN SHLD WRAP QUICKLY EWD SWD OF
MID LVL CYCLONE SUN NIGHT.
SFC RIDGING AND FLATTENING FLW ALOFT FOLLOW IN WAKE OF THIS SYS FOR
MID PD W/ABV NORMAL TEMPS DVLPG LT PD IN RESPONSE TO RENEWED DEEP
WRN TROUGHING TWD DYS 6-7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 140 PM EDT FRI OCT 4 2013
ABUNDANT MOISTURE...MODEST INSTABILITY AND A SUBTLE SHORT WAVE
COMBINED WITH TRIGGER TEMPERATURES IN THE LOWER 80S HAVE LED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EARLY THIS AFTERNOON.
SLIGHTLY BETTER INSTABILITY TOWARD KFWA SO INCLUDED A TEMPO TSRA
THERE COUPLED WITH RADAR TRENDS. WEAKER RETURNS TOWARD KSBN SO KEPT
THIS AS JUST A SHRA. REMAINDER OF FORECAST LATER THIS AFTERNOON AND
TONIGHT REMAIN UNCERTAIN FOR MANY REASONS. CONTINUED UNSTABLE AND
MOISTURE RICH ATMOSPHERE COULD ALLOW SHRA/TSRA TO DEVELOP THROUGH
THE PERIOD. BUT NO STRONG FORCING MAKES TIMING ANY PCPN AT TAF SITES
NEARLY IMPOSSIBLE. THEREFORE LEFT MENTION OUT AFTER THIS AFTERNOON.
FOG AND STRATUS ONCE AGAIN POSSIBLE OVERNIGHT BUT LIKE THIS MORNING
COULD BE HINDERED BY ANY CONVECTION AND LINGERING HIGHER CLOUDS.
KEPT A MVFR GROUP IN FOR NOW AND WILL WAIT TO SEE HOW THINGS
DEVELOP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...CEO
SYNOPSIS...CEO/KG
SHORT TERM...AGD
LONG TERM...T
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
141 PM EDT FRI OCT 4 2013
.SYNOPSIS...
ISSUED AT 113 PM EDT FRI OCT 4 2013
A WARM AND MOIST AIRMASS WILL REMAIN OVER THE REGION INTO THE
WEEKEND. PERIODIC SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON THROUGH LATE SATURDAY NIGHT WHEN A COLD FRONT APPROACHES
THE AREA FROM THE WEST. WELL ABOVE NORMAL TEMPERATURES WILL
CONTINUE WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID 60S.
&&
.UPDATE...
ISSUED AT 113 PM EDT FRI OCT 4 2013
GRID UPDATE EARLY THIS AFTERNOON TO ACCOUNT FOR DEVELOPMENT OF SCT
SHOWERS AND THUNDERSTORMS. BREAKS IN CLOUD COVER LATE THIS
MORNING AND EARLY AFTERNOON HAVE ALLOWED FOR TEMPERATURES TO
QUICKLY WARM INTO THE UPPER 70S TO LOW 80S IN MOST LOCATIONS. SCT
SHOWERS POPPING UP AS CONVECTIVE TEMPS REACHED WITH SB CAPE VALUES
EXCEEDING 1000 J/KG. LATEST HRRR AND RAP RUNS HAVE CAPTURED THIS
DECENTLY AND SUSPECT THIS ACTIVITY WILL CONTINUE INTO THE EVENING
HOURS. THEREFORE HAVE ADDED SCT TSRA ACROSS ENTIRE AREA THRU 00Z.
ONLY MINOR CHANGES MADE TO TEMPS AND SKY COVER GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM EDT FRI OCT 4 2013
LEE CYCLOGENESIS IS NOW WELL UNDERWAY ACROSS THE CENTRAL PLAINS
AS 100+ KT JET ROUNDS THE BASE OF LONGWAVE TROUGH PRESENTLY OVER
THE ROCKIES. ASSOCIATED VORT MAX IS VERY IMPRESSIVE WITH A CLASSIC
TREBLE CLEF SIGNATURE DEVELOPING ON THE 1.5 PVU SURFACE
TODAY...AND THE MAIN PV LOBE EXTENDING THROUGH MOST OF THE
TROPOSPHERE. THIS STRONG PV ADVECTION WILL COMBINE WITH GOOD
DIFFLUENCE ALOFT AND SOME SEMBLANCE OF A COUPLED UPPER JET
STRUCTURE TO SUPPORT CONTINUED STRENGTHENING OF THE CENTRAL PLAINS
SURFACE LOW. WHAT THIS MEANS LOCALLY IS THAT SOUTHWEST
FLOW/THETA-E ADVECTION WILL PERSIST THROUGH THE SHORT TERM WITH A
LITANY OF CONVECTIVELY ENHANCED SHORTWAVES CONTINUING TO IMPACT
THE SOUTHERN GREAT LAKES. SURFACE WARM FRONT WILL REMAIN DRAPED
JUST TO OUR NORTH AND SUBTLE HEIGHT RISES DOWNSTREAM OF
APPROACHING TROUGH SHOULD KEEP THE BULK OF OUR AREA DRY TODAY AS
THE FOCUS OF CONVECTION REMAINS IN LOWER MICHIGAN. CONFIDENCE IN
THIS SCENARIO REMAINS LOW HOWEVER GIVEN WEAK/BROAD 300-305K
ISENTROPIC ASCENT AND VERY LITTLE CONVECTIVE INHIBITION ON NEWEST
NAM AND GFS BUFR SOUNDINGS. NOTHING IN THE LATEST RADAR IMAGERY OR
HI-RES GUIDANCE TO SUPPORT ALTERING DRY FORECAST AFTER REMAINING
SHOWERS EXIT AROUND 12Z...BUT WILL HAVE TO KEEP AN EYE ON THIS
THROUGHOUT THE DAY AS AN ISOLATED SHOWERS/STORM IS CERTAINLY NOT
OUTSIDE THE REALM OF POSSIBILITY. THIS WILL BE ESPECIALLY TRUE IN
OUR FAR NORTHERN COUNTIES...CLOSER TO THE SURFACE WARM FRONT AND
EXPECTED TRAIN OF W-E ORIENTED CONVECTIVE CLUSTERS. CONFIDENCE IN
HIGH TEMP FORECAST IS SIMILARLY LOW. ANY SUSTAINED BREAKS IN CLOUD
COVER COULD ALLOW HIGHS TO SURGE WELL INTO THE MID 80S GIVEN 850MB
TEMPS AROUND 16C. EXPECT THERE WILL STILL BE A FAIR AMOUNT OF
CLOUDS IN THE AFTERNOON THOUGH AND WILL MAINTAIN HIGHS IN THE LOW
TO MID 80S. LITTLE CHANGES DURING THE OVERNIGHT PERIOD AS WE
REMAIN IN A REGION OF BROAD WARM/MOIST AIR ADVECTION. LACK OF
CLEAR FORCING MECHANISM AT THIS POINT WARRANTS JUST A LOW CHANCE
OF POPS. LOWS WILL BE VERY MILD...LIKELY NOT DROPPING MUCH BELOW
THE UPPER 60S IN THIS VERY MOIST ENVIRONMENT. COULD ALSO BE A FEW
AREAS OF FOG OVERNIGHT GIVEN POOLING MOISTURE AND LIGHT SURFACE
WINDS BENEATH A STRENGTHENING INVERSION. MAV AND MET GUIDANCE BOTH
SUPPORT PERIODS OF FOG BUT WITH THE FRONT NORTH OF HERE AND VERY
LITTLE FOG THIS MORNING...WILL LEAVE OUT MENTION FOR NOW AND LET
LATER SHIFT MODIFY AS NECESSARY.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 342 AM EDT FRI OCT 4 2013
VRY INTENSE SW TROUGH AND ATTENDANT UPR JET STREAK CARVING OUT AN
IMPRESSIVE CYCLONE ACRS THE CNTRL ROCKIES THIS MORNING. SFC LOW
CNTRD OVR SE CO WILL LIFT NEWD AND OCCLUDE INTO SAT MORNING ACRS
SERN SD AND YIELD A SLW EWD EJECTION OF SFC OCCLUSION. BROAD/MOIST WARM
SECTOR WILL PERSIST EWD ACRS THE LAKES/OH VALLEY YET W/MINIMAL
BACKGROUND FOCUS. THUS KEPT W/A MINIMIZED LOWER BLENDED POP THROUGH
SAT AFTN. CONTD EWD PROGRESSION OF OCCLUDED FNT LT SAT NIGHT WILL
BRING ABT A PD OF SHRA/TSRA AND LIKELY LINGER ACRS ERN ZONES THROUGH
SUN AFTN. OTRWS STG NEG THETA-E ADVTN SHLD WRAP QUICKLY EWD SWD OF
MID LVL CYCLONE SUN NIGHT.
SFC RIDGING AND FLATTENING FLW ALOFT FOLLOW IN WAKE OF THIS SYS FOR
MID PD W/ABV NORMAL TEMPS DVLPG LT PD IN RESPONSE TO RENEWED DEEP
WRN TROUGHING TWD DYS 6-7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 140 PM EDT FRI OCT 4 2013
ABUNDANT MOISTURE...MODEST INSTABILITY AND A SUBTLE SHORT WAVE
COMBINED WITH TRIGGER TEMPERATURES IN THE LOWER 80S HAVE LED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EARLY THIS AFTERNOON.
SLIGHTLY BETTER INSTABILITY TOWARD KFWA SO INCLUDED A TEMPO TSRA
THERE COUPLED WITH RADAR TRENDS. WEAKER RETURNS TOWARD KSBN SO KEPT
THIS AS JUST A SHRA. REMAINDER OF FORECAST LATER THIS AFTERNOON AND
TONIGHT REMAIN UNCERTAIN FOR MANY REASONS. CONTINUED UNSTABLE AND
MOISTURE RICH ATMOSPHERE COULD ALLOW SHRA/TSRA TO DEVELOP THROUGH
THE PERIOD. BUT NO STRONG FORCING MAKES TIMING ANY PCPN AT TAF SITES
NEARLY IMPOSSIBLE. THEREFORE LEFT MENTION OUT AFTER THIS AFTERNOON.
FOG AND STRATUS ONCE AGAIN POSSIBLE OVERNIGHT BUT LIKE THIS MORNING
COULD BE HINDERED BY ANY CONVECTION AND LINGERING HIGHER CLOUDS.
KEPT A MVFR GROUP IN FOR NOW AND WILL WAIT TO SEE HOW THINGS
DEVELOP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...CEO
SYNOPSIS...CEO
SHORT TERM...AGD
LONG TERM...T
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
113 PM EDT FRI OCT 4 2013
.SYNOPSIS...
ISSUED AT 113 PM EDT FRI OCT 4 2013
A WARM AND MOIST AIRMASS WILL REMAIN OVER THE REGION INTO THE
WEEKEND. PERIODIC SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON THROUGH LATE SATURDAY NIGHT WHEN A COLD FRONT APPROACHES
THE AREA FROM THE WEST. WELL ABOVE NORMAL TEMPERATURES WILL
CONTINUE WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID 60S.
&&
.UPDATE...
ISSUED AT 113 PM EDT FRI OCT 4 2013
GRID UPDATE EARLY THIS AFTERNOON TO ACCOUNT FOR DEVELOPMENT OF SCT
SHOWERS AND THUNDERSTORMS. BREAKS IN CLOUD COVER LATE THIS
MORNING AND EARLY AFTERNOON HAVE ALLOWED FOR TEMPERATURES TO
QUICKLY WARM INTO THE UPPER 70S TO LOW 80S IN MOST LOCATIONS. SCT
SHOWERS POPPING UP AS CONVECTIVE TEMPS REACHED WITH SB CAPE VALUES
EXCEEDING 1000 J/KG. LATEST HRRR AND RAP RUNS HAVE CAPTURED THIS
DECENTLY AND SUSPECT THIS ACTIVITY WILL CONTINUE INTO THE EVENING
HOURS. THEREFORE HAVE ADDED SCT TSRA ACROSS ENTIRE AREA THRU 00Z.
ONLY MINOR CHANGES MADE TO TEMPS AND SKY COVER GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM EDT FRI OCT 4 2013
LEE CYCLOGENESIS IS NOW WELL UNDERWAY ACROSS THE CENTRAL PLAINS
AS 100+ KT JET ROUNDS THE BASE OF LONGWAVE TROUGH PRESENTLY OVER
THE ROCKIES. ASSOCIATED VORT MAX IS VERY IMPRESSIVE WITH A CLASSIC
TREBLE CLEF SIGNATURE DEVELOPING ON THE 1.5 PVU SURFACE
TODAY...AND THE MAIN PV LOBE EXTENDING THROUGH MOST OF THE
TROPOSPHERE. THIS STRONG PV ADVECTION WILL COMBINE WITH GOOD
DIFFLUENCE ALOFT AND SOME SEMBLANCE OF A COUPLED UPPER JET
STRUCTURE TO SUPPORT CONTINUED STRENGTHENING OF THE CENTRAL PLAINS
SURFACE LOW. WHAT THIS MEANS LOCALLY IS THAT SOUTHWEST
FLOW/THETA-E ADVECTION WILL PERSIST THROUGH THE SHORT TERM WITH A
LITANY OF CONVECTIVELY ENHANCED SHORTWAVES CONTINUING TO IMPACT
THE SOUTHERN GREAT LAKES. SURFACE WARM FRONT WILL REMAIN DRAPED
JUST TO OUR NORTH AND SUBTLE HEIGHT RISES DOWNSTREAM OF
APPROACHING TROUGH SHOULD KEEP THE BULK OF OUR AREA DRY TODAY AS
THE FOCUS OF CONVECTION REMAINS IN LOWER MICHIGAN. CONFIDENCE IN
THIS SCENARIO REMAINS LOW HOWEVER GIVEN WEAK/BROAD 300-305K
ISENTROPIC ASCENT AND VERY LITTLE CONVECTIVE INHIBITION ON NEWEST
NAM AND GFS BUFR SOUNDINGS. NOTHING IN THE LATEST RADAR IMAGERY OR
HI-RES GUIDANCE TO SUPPORT ALTERING DRY FORECAST AFTER REMAINING
SHOWERS EXIT AROUND 12Z...BUT WILL HAVE TO KEEP AN EYE ON THIS
THROUGHOUT THE DAY AS AN ISOLATED SHOWERS/STORM IS CERTAINLY NOT
OUTSIDE THE REALM OF POSSIBILITY. THIS WILL BE ESPECIALLY TRUE IN
OUR FAR NORTHERN COUNTIES...CLOSER TO THE SURFACE WARM FRONT AND
EXPECTED TRAIN OF W-E ORIENTED CONVECTIVE CLUSTERS. CONFIDENCE IN
HIGH TEMP FORECAST IS SIMILARLY LOW. ANY SUSTAINED BREAKS IN CLOUD
COVER COULD ALLOW HIGHS TO SURGE WELL INTO THE MID 80S GIVEN 850MB
TEMPS AROUND 16C. EXPECT THERE WILL STILL BE A FAIR AMOUNT OF
CLOUDS IN THE AFTERNOON THOUGH AND WILL MAINTAIN HIGHS IN THE LOW
TO MID 80S. LITTLE CHANGES DURING THE OVERNIGHT PERIOD AS WE
REMAIN IN A REGION OF BROAD WARM/MOIST AIR ADVECTION. LACK OF
CLEAR FORCING MECHANISM AT THIS POINT WARRANTS JUST A LOW CHANCE
OF POPS. LOWS WILL BE VERY MILD...LIKELY NOT DROPPING MUCH BELOW
THE UPPER 60S IN THIS VERY MOIST ENVIRONMENT. COULD ALSO BE A FEW
AREAS OF FOG OVERNIGHT GIVEN POOLING MOISTURE AND LIGHT SURFACE
WINDS BENEATH A STRENGTHENING INVERSION. MAV AND MET GUIDANCE BOTH
SUPPORT PERIODS OF FOG BUT WITH THE FRONT NORTH OF HERE AND VERY
LITTLE FOG THIS MORNING...WILL LEAVE OUT MENTION FOR NOW AND LET
LATER SHIFT MODIFY AS NECESSARY.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 342 AM EDT FRI OCT 4 2013
VRY INTENSE SW TROUGH AND ATTENDANT UPR JET STREAK CARVING OUT AN
IMPRESSIVE CYCLONE ACRS THE CNTRL ROCKIES THIS MORNING. SFC LOW
CNTRD OVR SE CO WILL LIFT NEWD AND OCCLUDE INTO SAT MORNING ACRS
SERN SD AND YIELD A SLW EWD EJECTION OF SFC OCCLUSION. BROAD/MOIST WARM
SECTOR WILL PERSIST EWD ACRS THE LAKES/OH VALLEY YET W/MINIMAL
BACKGROUND FOCUS. THUS KEPT W/A MINIMIZED LOWER BLENDED POP THROUGH
SAT AFTN. CONTD EWD PROGRESSION OF OCCLUDED FNT LT SAT NIGHT WILL
BRING ABT A PD OF SHRA/TSRA AND LIKELY LINGER ACRS ERN ZONES THROUGH
SUN AFTN. OTRWS STG NEG THETA-E ADVTN SHLD WRAP QUICKLY EWD SWD OF
MID LVL CYCLONE SUN NIGHT.
SFC RIDGING AND FLATTENING FLW ALOFT FOLLOW IN WAKE OF THIS SYS FOR
MID PD W/ABV NORMAL TEMPS DVLPG LT PD IN RESPONSE TO RENEWED DEEP
WRN TROUGHING TWD DYS 6-7.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 555 AM EDT FRI OCT 4 2013
MAINLY VFR CONDITIONS EXPECTED TODAY AS SURFACE WARM FRONT AND
ASSOCIATED CONVECTION REMAIN DRAPED JUST NORTH OF OUR AREA. LOW
END VFR CEILINGS POSSIBLE ONCE DIURNAL HEATING BEGINS BUT FOCUS OF
WARM/MOIST AIR ADVECTION WILL KEEP MOST PRECIP NORTH AND WEST OF
THE TERMINALS. PATCHY FOG IS POSSIBLE AGAIN TONIGHT GIVEN LIGHT
WINDS AND HIGH SURFACE DEWPOINTS. MAV AND MET GUIDANCE SHOW
PERIODS OF FOG DEVELOPING BUT CLOUD COVER MAY INHIBIT RADIATIONAL
LOSSES ONCE AGAIN AND WILL HOLD OFF ON ANY MENTION FOR NOW GIVEN
ONLY WEAK SIGNAL SEEN IN FORECAST SOUNDINGS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...CEO
SYNOPSIS...CEO
SHORT TERM...AGD
LONG TERM...T
AVIATION...AGD
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1244 PM CDT FRI OCT 4 2013
.UPDATE...
ISSUED AT 1236 PM CDT FRI OCT 4 2013
UPDATED THE FORECAST TO REFLECT CURRENT TRENDS ACROSS MY CWA.
ABUNDANT CLOUD COVER AND SCATTERED SHOWERS AND THUNDERSTORMS ARE
KEEPING TEMPERATURES LOWER THAN PREVIOUSLY FORECAST SO
TEMPERATURES WERE LOWER BY ROUGHLY 5 DEGREES ALONG AND NORTH OF
INTERSTATE 80 TO A COUPLE OF DEGREES TO THE SOUTH. WILL BE A BREAK
IN THE ACTIVITY THIS AFTERNOON BEFORE THE DEVELOPMENT OF SHOWERS
AND THUNDERSTORMS ARE EXPECTED BY LATE AFTERNOON INTO THE EARLY
EVENING.
$$
DC
UPDATE ISSUED AT 648 AM CDT FRI OCT 4 2013
THE FIRST STORM COMPLEX IS MOVING INTO SOUTHERN WISCONSIN. THE
NEXT STORM SYSTEM IN WESTERN/CENTRAL IOWA IS SLOWLY FALLING APART
BUT ISOLATED TO SCATTERED SHOWERS AND SOME THUNDERSTORMS WILL BE
POSSIBLE THROUGH LATE MORNING.
THERE ARE CONCERNS ABOUT TEMPERATURES DUE TO CLOUD COVER AND THE
REMNANT COLD POOL FROM THE OVERNIGHT STORMS. THE COLD POOL AND
CLOUD COVER MAY SUPPRESS TEMPERATURES ACROSS THE NORTHERN CWFA
DURING THE DAY WITH COOLER THAN EXPECTED READINGS. THE EDGE OF THE
COLD POOL WILL ALSO PROVIDE A BOUNDARY FOR ISOLATED TO SCATTERED
CONVECTION DURING THE AFTERNOON AND EVENING HOURS.
&&
.SYNOPSIS...
ISSUED AT 248 AM CDT FRI OCT 4 2013
06Z SFC ANALYSIS HAD A WEAK LOW NEAR KOLZ WITH ADDITIONAL LOWS FROM
NORTHWEST KANSAS INTO SOUTHEAST COLORADO. THE MAIN FRONT RAN FROM
UPPER MICHIGAN...TO NEAR KOLZ...BACK TO AROUND KHLC. WEAK BOUNDARIES
FROM CONVECTION WERE ACROSS NORTHERN ILLINOIS AND EASTERN IOWA. DEW
POINTS WERE IN THE 60S SOUTH AND EAST OF THE FRONT WITH 40S AND 50S
BEHIND THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 248 AM CDT FRI OCT 4 2013
THE CURRENT CONVECTION IS BEING SUPPORTED BY A DISTURBANCE ALOFT.
PER THE GEM REGIONAL AND RAP TRENDS THIS SHORTWAVE WILL ALLOW
CONVECTION TO PERSIST THROUGH SUNRISE AND THE MORNING HOURS
GENERALLY NORTH OF I-80. INTERACTION WITH BOUNDARIES MAY ALLOW
ISOLATED CONVECTION TO DEVELOP JUST SOUTH OF I-80.
ONCE THE SHORTWAVE PASSES A LULL IN PRECIPITATION SHOULD BE SEEN
THROUGH THE AFTERNOON. DIFFERENTIAL HEATING MAY ALLOW ISOLATED TO
LOW END SCATTERED CONVECTION TO DEVELOP DURING THE HEAT OF THE DAY.
THE SEVERE WEATHER THREAT TODAY APPEARS TO BE LOW RIGHT NOW.
TEMPERATURES WILL BE HIGHLY DEPENDENT UPON CLOUD COVER AND
PRECIPITATION. THE POTENTIAL DOES EXIST FOR A 15 DEGREE GRADIENT
ACROSS THE AREA WITH THE COOLEST READINGS IN THE HWY 20 CORRIDOR.
TONIGHT...ISOLATED TO LOW END SCATTERED CONVECTION SHOULD BE SEEN
DURING THE EVENING. BETTER FORCING ASSOCIATED WITH THE MAIN COLD
FRONT IS EXPECTED TO ALLOW MORE WIDESPREAD CONVECTION TO DEVELOP
DURING THE LATE EVENING AND OVERNIGHT HOURS THAT MOVES FROM WEST TO
EAST ACROSS THE CWFA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 248 AM CDT FRI OCT 4 2013
EARLY FALL COLD TO BRING COLDEST AIR OF THE FALL WITH RISK OF
PATCHY FROST WITH DRY WEATHER AFTER ITS PASSAGE.
OVERVIEW...INITIALIZATION AND VERIFICATION FAIR WITH ONGOING
PROBLEMS WITH COLD AIR IN PLAINS UNDERDONE. THIS HAS BEEN THE CASE
THE PAST 24 PLUS HOURS WITH A MORE SOUTHERLY AND TRACK OF LOW AND
ALSO COLDER WEATHER AFTER FRONT. THIS IS RELATED TO STRONG NEGATIVE
FEEDBACK ISSUES OF MAJOR SNOWS IN NORTHERN HIGH PLAINS AND DEEP
MOIST AIR. SOME FURTHER SHIFT OF LOW TRACK SUPPORTED NEXT 24 HOURS
WITH UPPER LOW PASSING OVER AT LEAST NORTH SECTIONS WITH A DEEPLY
OCCLUDED LOW SYSTEM ON SUNDAY. CONTINUITY AND THERMAL FIELDS
SUPPORTS A 70/30 MIX OF HI-RES ECMWF AND GFS. THIS WOULD SUGGEST
COLDER TEMPERATURES AFTER FRONTAL PASSAGE AND SLIGHT COLDER TEMPERATURES
INTO TUESDAY AM FOR LATER SHIFTS.
SATURDAY...DEEPLY OCCLUDED SURFACE FRONT TO PASS IN AM WITH LIMITED
INSTABILITY FOR SHOWERS AND ISOLATED EMBEDDED STORMS THAT WOULD NOT
BE SEVERE. RAISED POPS WITH DEEPER FORCING WITH WIDESPREAD MODERATE
RAIN AMOUNTS WITH PASSAGE. FALLING TEMPERATURES MOST OF THE REGION
BY MID/LATE PM WITH BLUSTERY WESTERLY WINDS. SATURDAY NIGHT..DRY
SLOW FOR CLEAR TO PARTLY CLOUDY SKIES AND LOW DEWPOINT AND LOTS OF
COLD AIR ALOFT MAY ALLOW FOR UPPER 30S FOR LATER SHIFTS TO
REASSESS. THIS MAY ALSO BE NEEDED WITH COLDER TRENDS FROM NEGATIVE
FEEDBACK ISSUES DISCUSSED EARLIER. IF FRONT ARRIVES SOONER THEN
HIGHS WILL NEED LOWERING BY 5 DEGREES OR MORE FOR LATER SHIFTS TO
RECONSIDER.
SUNDAY...INCREASED POPS...CLOUDS AND A BIT COLDER WITH NW SECTIONS
POSSIBLY NEEDING LOWERING BY AT LEAST ANOTHER CATEGORY WITH NEAR
50F READINGS NOT OUT OF THE QUESTION. LIGHT RAIN AND SHOWERS WITH
DIURNAL HEATING MAY NEED RAISING TO LIKELY OVER NORTHERN SECTIONS
WITH A FEW HUNDREDTHS OF AN INCH...ENOUGH TO WET THE GROUND. BLUSTERY
WESTERLY WINDS OF 15 TO 25 MPH TO MAKE COOLER WEATHER MORE NOTICEABLE.
SUNDAY NIGHT...CLEARING AND COOL WITH KEY QUESTION OF BL DECOUPLING
AND CLEARING...IF THIS OCCURS THEN LOWS TO NEAR FREEZING ARE POSSIBLE
FOR LATER SHIFTS TO REASSESS. THE POOR CONFIDENCE IN MODEL TRENDS
MAKE THIS POOR TO QUANTIFY ATTM.
MONDAY AND TUESDAY...FAIR WITH A WARMING TREND WITH WIDE DIURNAL
TEMPERATURE CHANGES. LATER SHIFTS MAY NEED TO TRIM MINS BY A CATEGORY.
HIGHS IN THE 60S MONDAY AND UPPER 60S TO LOWER 70S TUESDAY WITH LOWS
TUESDAY AM CURRENTLY IN THE MIDDLE 40S.
WEDNESDAY AND THURSDAY...MILD WITH LIGHT TO MODERATE SOUTHERLY WINDS
AND FAIR SKIES TO MAKE NICE EARLY OCTOBER WEATHER. HIGHS IN THE 70S
AND LOWS MOSTLY IN THE LOWER 50S. UPPER 40S IN FAVORED LOW LYING
LOCATIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1236 PM CDT FRI OCT 4 2013
SCATTERED SHOWERS AND THUNDERSTORMS ARE CURRENTLY MOVING THROUGH
KDBQ...KMLI...AND KBRL. CURRENT MVFR CEILINGS AND VISIBILITIES
WILL QUICKLY IMPROVE OVER THE NEXT HOUR AS THIS LINE OF SHOWERS
AND THUNDERSTORMS EXITS EASTWARD. SHOULD BE A BREAK IN ACTIVITY
THIS AFTERNOON BEFORE THE REDEVELOPMENT OF SHOWER AND
THUDNERSTORMS ACTIVITY THIS EVENING AND CONTINUING OVERNIGHT AHEAD
OF A COLD FRONT THAT WILL MOVE THROUGH THE REGION AROUND 18 UTC ON
SATURDAY. EXPECT AT LEAST MVFR CEILINGS TO DEVELOP AT ALL TAF
SITES BY LATE TONIGHT AND CONTINUE INTO THE MORNING. SOUTHERLY
WINDS WILL INCREASE BY MID MORNING ON SATURDAY AND QUICKLY BECOME
SOUTHWESTERLY AS THE FRONT APPROACHES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...DC
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...DC
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1229 PM CDT Fri Oct 4 2013
.UPDATE...
ISSUED AT 1223 PM CDT FRI OCT 4 2013
Updated the aviation section for the 18Z TAF issuance.
&&
UPDATE ISSUED AT 1109 AM CDT FRI OCT 4 2013
A little uncomfortable broad-brushing PoPs and weather for the
remainder of this first period (this afternoon), so went more
conservative with the coverage versus intensity of the convective
activity.
With yesterday`s package, had originally expected the overnight
convection to be over southwest Illinois, but it ended up over the
lower Wabash valley. In addition, where the stable layer clouds
over Southwest Illinois and Southeast Missouri have been noted
this morning, expected isolated to widely scattered convection.
For today, differential heating and theta-e convergence along and
east of the stable cloud layer should aid in convection from noon
into the middle of the afternoon. Spatially adjusted HRRR guidance
seems to have a decent handle on the main area of convection this
afternoon. GOES Lifted index values are falling at or below zero
as of 15z, and GOES Precipitable Water values are running around
1.5 inches. This should yield a quick 0.60-0.70 inch hourly
amounts in small, but heavy rain showers or thunderstorms this
afternoon.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 406 AM CDT FRI OCT 4 2013
Have just a few light showers over the Evansville Tri State Region
early this morning. They are moving northeast and should be out of
the area near sunrise.
The 00Z models raise 500mb heights across the region and struggle
to generate much QPF today. However, with temperatures pushing record
levels this afternoon and dewpoints pooling in the upper 60s,
will leave a 20-30 PoP for diurnal potential. Any storms this
afternoon should dissipate with sunset, leaving the evening dry
across the entire region.
The 00Z models really do not have a coherent signal on best
placement of QPF late tonight through much of Saturday. One fairly
common signal is for convective development over southeast
Missouri late tonight that then spreads across much of west
Kentucky through midday Saturday. This activity would be well
ahead of the front. In general, the emphasis would shift to the
northwest fringe of the area late in the afternoon, as the primary
frontal convective band approaches. This should continue eastward
across southeast Missouri and southern Illinois in the evening, as
the front pushes eastward across the area.
The best signal in the models seems to be that the front will slow
down, if not hang up completely, near our eastern border late
Saturday night. The 00Z NAM really holds it up, and generates an
intense band of QPF over west Kentucky through Sunday morning. It
has strong frontogenetical forcing around 925mb along with
slightly negative Showalter indices and an extreme amount of
moisture to play with, which result in a relatively narrow band of
torrential rainfall. The 00Z GFS has similar forcing, but it is
more progressive, which seems more realistic given the constant
eastward movement of the parent storm system. The 06Z NAM is more
progressive. Will cap PoPs at likely levels Saturday and then
ramp up to categoricals in the southeast Saturday night and
Sunday.
The models all have trended slower with the system as a whole,
which keeps significant PoPs and QPf over the southeast half of
the area through much of Sunday. Even left a sliver of a slight
chance in the far east into Sunday evening. Will not mention heavy
rain in the grids at this time, due to the likely progressive
nature of the heaviest band. If confidence increases in a more
prolonged period of heavy rainfall over west Kentucky with
subsequent model cycles, a Flash Flood Watch may need to be
considered.
As for severe weather, instability will be lacking on Saturday due
to a general lack of insolation expected. The best wind fields
definitely lag the frontal convection, but there may be enough
unidirectional shear through the column to support a few line
segments within the primary frontal band, mainly into Saturday
evening over southeast Missouri and southern Illinois. However, heavy
rainfall and frequent lightning will be the bigger concerns
Saturday through Sunday.
As for temperatures, given that any convection is expected to
be diurnal in nature this afternoon, figure the warmer MAV numbers
will be closer for highs. The opposite will be true for Saturday,
as the cooler MET numbers should be closer to reality. Leaned
toward the consensus of raw model data for highs behind the front
on Sunday. Lows will be mild tonight, consensus guidance may not
be warm enough. Did not stray far from the consensus of raw model
data for Saturday nights lows.
.LONG TERM...(Monday through Thursday)
ISSUED AT 406 AM CDT FRI OCT 4 2013
Surface high pressure will build across the Great Lakes region into
the southern plains for the early part of the work week. Dry
conditions and cooler than average temperatures can be expected
Monday into Monday night, with temperatures moderating back to near
seasonal Tuesday into Tuesday night.
By Tuesday night into Wednesday night, ECMWF, GEM and GFS all bring
an upper level low from the gulf coast states over the eastern U.S.
ECMWF and GEM show the track of this low farther west over eastern
Kentucky by mid week, while GFS tracks the low farther east along
the central Atlantic coast. The ECMWF and GEM show some significant
moisture with the low, but keep any precip just east of the PAH
forecast area. To account for this, increased cloud cover late
Tuesday night through Thursday evening, mainly across our eastern
counties.
Winds will become southerly for mid to late week as the Great Lakes
high moves off the east coast. This will continue the gradual warm
up, with readings a few degrees above normal by Thursday.
&&
.AVIATION...
ISSUED AT 1223 PM CDT FRI OCT 4 2013
MVFR possible at KCGI for the first couple of hours, otherwise VFR
conditions expected at all sites through at least 10Z. Beyond that
VCSH/SHRA could easily push cigs and/or vsbys into MVFR territory
through the end of the period. South to south southwest winds aob
10 knots should prevail through the period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM/FIRE WX...SMITH
LONG TERM/AVIATION...JP
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1109 AM CDT Fri Oct 4 2013
.UPDATE...
ISSUED AT 1109 AM CDT FRI OCT 4 2013
A little uncomfortable broad-brushing PoPs and weather for the
remainder of this first period (this afternoon), so went more
conservative with the coverage versus intensity of the convective
activity.
With yesterday`s package, had originally expected the overnight
convection to be over southwest Illinois, but it ended up over the
lower Wabash valley. In addition, where the stable layer clouds
over Southwest Illinois and Southeast Missouri have been noted
this morning, expected isolated to widely scattered convection.
For today, differential heating and theta-e convergence along and
east of the stable cloud layer should aid in convection from noon
into the middle of the afternoon. Spatially adjusted HRRR guidance
seems to have a decent handle on the main area of convection this
afternoon. GOES Lifted index values are falling at or below zero
as of 15z, and GOES Precipitable Water values are running around
1.5 inches. This should yield a quick 0.60-0.70 inch hourly
amounts in small, but heavy rain showers or thunderstorms this
afternoon.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 406 AM CDT FRI OCT 4 2013
Have just a few light showers over the Evansville Tri State Region
early this morning. They are moving northeast and should be out of
the area near sunrise.
The 00Z models raise 500mb heights across the region and struggle
to generate much QPF today. However, with temperatures pushing record
levels this afternoon and dewpoints pooling in the upper 60s,
will leave a 20-30 PoP for diurnal potential. Any storms this
afternoon should dissipate with sunset, leaving the evening dry
across the entire region.
The 00Z models really do not have a coherent signal on best
placement of QPF late tonight through much of Saturday. One fairly
common signal is for convective development over southeast
Missouri late tonight that then spreads across much of west
Kentucky through midday Saturday. This activity would be well
ahead of the front. In general, the emphasis would shift to the
northwest fringe of the area late in the afternoon, as the primary
frontal convective band approaches. This should continue eastward
across southeast Missouri and southern Illinois in the evening, as
the front pushes eastward across the area.
The best signal in the models seems to be that the front will slow
down, if not hang up completely, near our eastern border late
Saturday night. The 00Z NAM really holds it up, and generates an
intense band of QPF over west Kentucky through Sunday morning. It
has strong frontogenetical forcing around 925mb along with
slightly negative Showalter indices and an extreme amount of
moisture to play with, which result in a relatively narrow band of
torrential rainfall. The 00Z GFS has similar forcing, but it is
more progressive, which seems more realistic given the constant
eastward movement of the parent storm system. The 06Z NAM is more
progressive. Will cap PoPs at likely levels Saturday and then
ramp up to categoricals in the southeast Saturday night and
Sunday.
The models all have trended slower with the system as a whole,
which keeps significant PoPs and QPf over the southeast half of
the area through much of Sunday. Even left a sliver of a slight
chance in the far east into Sunday evening. Will not mention heavy
rain in the grids at this time, due to the likely progressive
nature of the heaviest band. If confidence increases in a more
prolonged period of heavy rainfall over west Kentucky with
subsequent model cycles, a Flash Flood Watch may need to be
considered.
As for severe weather, instability will be lacking on Saturday due
to a general lack of insolation expected. The best wind fields
definitely lag the frontal convection, but there may be enough
unidirectional shear through the column to support a few line
segments within the primary frontal band, mainly into Saturday
evening over southeast Missouri and southern Illinois. However, heavy
rainfall and frequent lightning will be the bigger concerns
Saturday through Sunday.
As for temperatures, given that any convection is expected to
be diurnal in nature this afternoon, figure the warmer MAV numbers
will be closer for highs. The opposite will be true for Saturday,
as the cooler MET numbers should be closer to reality. Leaned
toward the consensus of raw model data for highs behind the front
on Sunday. Lows will be mild tonight, consensus guidance may not
be warm enough. Did not stray far from the consensus of raw model
data for Saturday nights lows.
.LONG TERM...(Monday through Thursday)
ISSUED AT 406 AM CDT FRI OCT 4 2013
Surface high pressure will build across the Great Lakes region into
the southern plains for the early part of the work week. Dry
conditions and cooler than average temperatures can be expected
Monday into Monday night, with temperatures moderating back to near
seasonal Tuesday into Tuesday night.
By Tuesday night into Wednesday night, ECMWF, GEM and GFS all bring
an upper level low from the gulf coast states over the eastern U.S.
ECMWF and GEM show the track of this low farther west over eastern
Kentucky by mid week, while GFS tracks the low farther east along
the central Atlantic coast. The ECMWF and GEM show some significant
moisture with the low, but keep any precip just east of the PAH
forecast area. To account for this, increased cloud cover late
Tuesday night through Thursday evening, mainly across our eastern
counties.
Winds will become southerly for mid to late week as the Great Lakes
high moves off the east coast. This will continue the gradual warm
up, with readings a few degrees above normal by Thursday.
&&
.AVIATION...
ISSUED AT 638 AM CDT FRI OCT 4 2013
The four state region will be firmly in the warm sector of a
developing storm system throughout the 12Z TAF period. Winds will
be from the south through the period. Generally light at night,
and increasing during the day towards 10kts with some gusts near
15kts possible, especially at KCGI.
An area of IFR ceilings over the Ozarks of southeast Missouri will
flirt with KCGI for a few hours this morning. Put a prevailing
1kft ceiling in to handle it. May see some isolated convection
this afternoon, but the expected coverage is too low to mention
the potential in any of the TAFs. A scattered cu layer is expected
along with some periodic mid-level ceilings.
Guidance has been fairly persistent in generating shra/tsra over
southeast Missouri and the Purchase area of west Kentucky late
tonight. This may be rather expansive, so will mention the
potential in a PROB30 group at KCGI and KPAH. KPAH looks like it
will be the most likely to get hit late tonight. There should be
enough wind to keep fog from forming at any of the sites late
tonight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...Smith
SHORT TERM...DRS
LONG TERM...RST
AVIATION...DRS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
513 PM EDT FRI OCT 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH SATURDAY
WHILE A STATIONARY FRONT REMAINS OVER SOUTHERN NEW ENGLAND AND
EASTERN NEW YORK STATE. LOW PRESSURE WILL PULL A WARM FRONT NORTH
ACROSS THE AREA LATE SUNDAY OR SUNDAY NIGHT...WITH A TRAILING
COLD FRONT TO CROSS THE REGION TUESDAY. SOME OF THE MOISTURE FROM
THE REMAINS OF TROPICAL STORM KAREN MAY MOVE UP ALONG THIS FRONT.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATE...A FEW MINOR CHANGES TO KEEP FORECAST IN LINE WITH CURRENT
OBSERVATIONAL TRENDS. HAVE TRENDED POP LOWER TO ACCOUNT FOR DRYING
IN ASSOCIATION WITH RIDGING OVER NRN ME EATING AWAY AT INCOMING
CLOUDS/PCPN.
PREVIOUS DISCUSSION...CLOUD SHIELD HAS FINALLY REACHED EASTERN
PORTIONS OF THE FORECAST AREA...DESPITE DRY AIR ASSOCIATED WITH
SURFACE HIGH PRESSURE OVER NORTHERN NEW ENGLAND. AN AREA OF
SHOWERS HAS JUST EXITED THE NH SEACOAST...MUCH IN LINE WITH THE
TIMING OF THE LATEST HRRR MODEL. MORE SHOWERS CONTINUE TO DEVELOP
OVER QUEBEC PROVINCE AND SLIDE TO THE SOUTH AND EAST. THERE IS
STILL A GOOD AMOUNT OF DRY AIR IN THE SOUNDING...HOWEVER A FEW OF
THESE SHOWERS MAY SURVIVE THE TRIP THROUGH THE REGION.
PLACED A SMALL AREA OF PATCHY LATE NIGHT FOG INTO THE CT RIVER
VALLEY TONIGHT. DESPITE CLOUD COVER...SOME FOG MAY DEVELOP IN THE
LEBANON AND ADJACENT VALLEY AREAS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
THE BATTLE BETWEEN THE RIDGE TO OUR NORTH AND EAST...AND A
STATIONARY FRONT TO OUR SOUTH AND WEST WILL CONTINUE ON SATURDAY
AND SATURDAY NIGHT. BY LATE SATURDAY NIGHT...THIS FRONT ADVANCES
TOWARDS NORTHERN NEW ENGLAND AS A WARM FRONT. LIMITED MOISTURE
MOVING INTO THE RIDGE UNDER A WARM AIR ADVECTION PATTERN MAY BRING
A FEW LIGHT SHOWERS TO THE REGION. THE PROBABILITY OF
PRECIPITATION WILL INCREASE LATE SATURDAY NIGHT AS THE FRONT APPROACHES.
USED A BLEND OF MET/MAV MOS FOR TEMPS THIS PERIOD.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
A DIRTY UPPER RIDGE AXIS WILL EXTEND ACROSS NEW ENGLAND BUT A
SHORT WAVE MOVES THROUGH ON SUNDAY AS A VERY MOIST ONSHORE SSELY
FLOW DEVELOPS ALLOWING OVERRUNNING RAINS TO DEVELOP FROM S-N DURING
THE DAY SUNDAY AND CONTINUE SUNDAY NIGHT INTO MON NIGHT AND PSBLY
TUE. OVERNIGHT LOWS WILL REMAIN MILD BUT DAYTIME HIGHS WILL REMAIN
COOL DUE TO THE ONSHORE FLOW EVEN THO H85 TEMPS WILL BE +12 TO
+14C. THE MOISTURE THAT WILL BE ASSOCIATED FROM THE REMNANTS OF
KAREN WILL ALSO GET ENTRAINED EARLY NEXT WEEK INTO THE SOUTHERLY
FLOW ALOFT SO SOME HEAVY RAINS EXPECTED. BY WED AND THU THE GT
LAKES UPR LOW DRIFTS EWD OVER NEW ENGL WITH A COOL CYCLONIC FLOW
ALOFT SO A FEW INSTBLTY MAINLY AFTN SHWRS CAN`T BE RULED OUT EACH
DAY BUT MAINLY IN THE MTNS. TEMPS TO REMAIN COOL THRU THE END OF
THE WEEK DUE TO THE CYCLONIC UPR LOW OVER THE REGION.
USED A BLEND OF THE EURO/MAV/MET/MEX GUID FOR THIS PCKG.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...CHALLENGING FORECAST FOR TONIGHT IN TERMS OF CLOUD
COVER AND POSSIBLE FOG. PLAN ON KEEPING ANY FOG LIMITED TO THE CT
RIVER VALLEY...AND ONLY BRIEFLY FOR LATE TONIGHT.
LONG TERM...SUN THRU LATE MON MVFR TO IFR CONDS EXPECTED IN
RN/SHWRS/PATCHY DRZL. AREAS OF FOG ALG THE COAST WILL DEVELOP SUN
NIGHT INTO MON REDUCING CONDS TO LIFR AT KPWM/KPSM/KRKD. IPVG
CONDS EXPECTED TO MOSTLY VFR BY MIDWEEK.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA.
LONG TERM...WINDS AND SEAS WILL INCREASE BUT SHOULD REMAIN JUST
BELOW SCA CRITERIA THROUGH MIDWEEK.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS GRAY ME
248 PM EDT FRI OCT 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH SATURDAY
WHILE A STATIONARY FRONT REMAINS OVER SOUTHERN NEW ENGLAND AND
EASTERN NEW YORK STATE. LOW PRESSURE WILL PULL A WARM FRONT NORTH
ACROSS THE AREA LATE SUNDAY OR SUNDAY NIGHT...WITH A TRAILING
COLD FRONT TO CROSS THE REGION TUESDAY. SOME OF THE MOISTURE FROM
THE REMAINS OF TROPICAL STORM KAREN MAY MOVE UP ALONG THIS FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
WSR-88D MODE CONFLICT REPAIRED. WE NOW REMAIN IN VCP21 LATE THIS AFTERNOON.
CLOUD SHIELD HAS FINALLY REACHED EASTERN PORTIONS OF THE FORECAST
AREA...DESPITE DRY AIR ASSOCIATED WITH SURFACE HIGH PRESSURE OVER
NORTHERN NEW ENGLAND. AN AREA OF SHOWERS HAS JUST EXITED THE NH
SEACOAST...MUCH IN LINE WITH THE TIMING OF THE LATEST HRRR MODEL.
MORE SHOWERS CONTINUE TO DEVELOP OVER QUEBEC PROVINCE AND SLIDE TO
THE SOUTH AND EAST. THERE IS STILL A GOOD AMOUNT OF DRY AIR IN THE
SOUNDING...HOWEVER A FEW OF THESE SHOWERS MAY SURVIVE THE TRIP
THROUGH THE REGION.
PLACED A SMALL AREA OF PATCHY LATE NIGHT FOG INTO THE CT RIVER
VALLEY TONIGHT. DESPITE CLOUD COVER...SOME FOG MAY DEVELOP IN THE
LEBANON AND ADJACENT VALLEY AREAS.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE BATTLE BETWEEN THE RIDGE TO OUR NORTH AND EAST...AND A
STATIONARY FRONT TO OUR SOUTH AND WEST WILL CONTINUE ON SATURDAY
AND SATURDAY NIGHT. BY LATE SATURDAY NIGHT...THIS FRONT ADVANCES
TOWARDS NORTHERN NEW ENGLAND AS A WARM FRONT. LIMITED MOISTURE
MOVING INTO THE RIDGE UNDER A WARM AIR ADVECTION PATTERN MAY BRING
A FEW LIGHT SHOWERS TO THE REGION. THE PROBABILITY OF
PRECIPITATION WILL INCREASE LATE SATURDAY NIGHT AS THE FRONT APPROACHES.
USED A BLEND OF MET/MAV MOS FOR TEMPS THIS PERIOD.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
A DIRTY UPPER RIDGE AXIS WILL EXTEND ACROSS NEW ENGLAND BUT A
SHORT WAVE MOVES THROUGH ON SUNDAY AS A VERY MOIST ONSHORE SSELY
FLOW DEVELOPS ALLOWING OVERUNNING RAINS TO DEVELOP FROM S-N DURING
THE DAY SUNDAY AND CONTINUE SUNDAY NIGHT INTO MON NIGHT AND PSBLY
TUE. OVERNIGHT LOWS WILL REMAIN MILD BUT DAYTIME HIGHS WILL REMAIN
COOL DUE TO THE ONSHORE FLOW EVEN THO H85 TEMPS WILL BE +12 TO
+14C. THE MOISTURE THAT WILL BE ASSOCIATED FROM THE REMNANTS OF
KAREN WILL ALSO GET ENTRAINED EARLY NEXT WEEK INTO THE SOUTHERLY
FLOW ALOFT SO SOME HEAVY RAINS EXPECTED. BY WED AND THU THE GT
LAKES UPR LOW DRIFTS EWD OVER NEW ENGL WITH A COOL CYCLONIC FLOW
ALOFT SO A FEW INSTBLTY MAINLY AFTN SHWRS CAN`T BE RULED OUT EACH
DAY BUT MAINLY IN THE MTNS. TEMPS TO REMAIN COOL THRU THE END OF
THE WEEK DUE TO THE CYCLONIC UPR LOW OVER THE REGION.
USED A BLEND OF THE EURO/MAV/MET/MEX GUID FOR THIS PCKG.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...CHALLENGING FORECAST FOR TONIGHT IN TERMS OF CLOUD
COVER AND POSSIBLE FOG. PLAN ON KEEPING ANY FOG LIMITED TO THE CT
RIVER VALLEY...AND ONLY BRIEFLY FOR LATE TONIGHT.
LONG TERM...SUN THRU LATE MON MVFR TO IFR CONDS EXPECTED IN
RN/SHWRS/PATCHY DRZL. AREAS OF FOG ALG THE COAST WILL DEVELOP SUN
NIGHT INTO MON REDUCING CONDS TO LIFR AT KPWM/KPSM/KRKD. IPVG
CONDS EXPECTED TO MOSTLY VFR BY MIDWEEK.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA.
LONG TERM...WINDS AND SEAS WILL INCREASE BUT SHOULD REMAIN JUST
BELOW SCA CRITERIA THROUGH MIDWEEK.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
1222 PM EDT FRI OCT 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH SATURDAY.
LOW PRESSURE WILL PULL A WARM FRONT NORTH ACROSS THE AREA LATE
SUNDAY OR SUNDAY NIGHT, WITH A TRAILING COLD FRONT TO CROSS THE
REGION MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
HAVE UPDATED GRIDS TO INCREASE POPS FURTHER FOR SOUTHERN NEW
HAMPSHIRE AND EXTREME SOUTHWEST MAINE FOR EARLY THIS AFTERNOON.
HAVE ALSO INCREASED CLOUD GRIDS FOR MUCH OF THE AREA BASED ON
LATEST STLT IMAGES AND SURFACE OBSERVATIONS.
LATEST HRRR MODEL BRINGS AN AREA OF PRECIPITATION EASTWARD...FROM
ABOUT PORTLAND AND POINTS SOUTH THIS AFTERNOON. SOME OF THIS
PRECIPITATION MAY NOT REACH THE GROUND AS A RIDGE OF HIGH PRESSURE
CONTINUES TO ENTER MAINE FROM QUEBEC PROVINCE.
PREV DISC...
UPDATED FORECAST TO ADD SLGT CHC OR CHC -SHRA TO SRN MOST ZONES
PER LATEST RADAR TRENDS...OTRW NO NOTICEABLE CHANGES TO THE
PREVIOUS FORECAST.
WEAK HIGH PRES OVER THE REGION TODAY GIVES US FAIR DRY WX WITH
MILD TEMPS. THERE WILL BE SOME MID TO HIGH LVL CLOUDS AROUND DUE
TO MOISTURE ALOFT MOVING THRU WITH A WEAK UPPER LEVEL SHORT WAVE
TROF THAT HAS LIMITED SUPPORT TO PRODUCE ANY PRCP AS IT WEAKENS
WHILE MOVING THRU THE BROAD UPPER LEVEL RIDGE OVER THE EASTERN US.
AREAS OF VALLEY FOG...MAINLY ACROSS NRN AND WRN NH SHOULD LIFT
SHORTLY AFTER SUNRISE. HIGHS EXPECTED TO REACH THE 60S N AND 70 TO
75 SOUTH THOUGH A DEVELOPING ONSHORE SEA BREEZE WILL LIKELY COOL
OFF COASTAL TOWNS A BIT THIS AFTERNOON. GENERALLY USED A BLEND OF
GFS/NAM AND MET/MAV MOS GUIDANCE ALONG WITH HPC QPF.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
WEAK HIGH PRES REMAINS IN CONTROL TNGT AND SATURDAY AS THE UPPER
LEVEL RIDGE STRENGTHENS OVER THE NE AS THE WEAKENING SHORT WAVE
TROF MOVES OFF TO THE EAST. STILL SOME CLOUDS LINGER DUE TO
TRAPPED MOISTURE UNDER THE SUBSIDENCE FROM HIGH PRES PUSHING IN
FROM THE NW. THIS WILL KEEP TEMPS FROM GETTING REAL COLD TNGT...
STILL SHOULD COOL DOWN INTO THE MID 30S TO LOWER 40S N AND INTO
THE 40S TO AROUND 50 S. CLOUDS WILL LIKELY HELP HOLD OFF ANY FOG
FORMING OVERNIGHT. MORE CLOUDS AROUND ON SATURDAY DESPITE THE HIGH
OVERHEAD AS A FRONTAL BOUNDARY TO OUR S BEGINS TO PUSH N SPREADING
HIGH AND MID LVL CLOUDS NORTHWARD. SHOULD BE MILD THOUGH CLOUDS
WILL HOLD TEMPS DOWN A BIT. STILL LOOKING FOR HIGHS IN THE LOWER
TO MID 60S N AND MID 60S TO AROUND 70 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
WE BEGIN THE PERIOD WITH MILD WEATHER UNDER A SHORT WAVE RIDGE. BY
MONDAY...A SHORT WAVE TROUGH ARRIVES FROM THE GREAT LAKES AND
DRIVES A SURFACE COLD FRONT ACROSS THE FORECAST AREA. IN THE WAKE
OF THE FRONTAL PASSAGE...WE STAY A BIT UNSETTLED THROUGH LATE WEEK
AS AN UPPER TROUGH LINGERS ACROSS THE REGION.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH SATURDAY/...DESPITE LOTS OF HIGH AND MID LVL
CLOUDS TODAY WITH SOME LOWER OF CIG TNGT INTO SATURDAY IT SHOULD
BE VFR THRU THE SHORT TERM EXCEPT FOR AREAS OF VALLEY FOG THAT
WILL MOST LIKELY IMPACT LEB AND MAYBE HIE EARLY THIS MORNING.
LONG TERM...
SUN NIGHT - MON...AREAS OF MVFR IN SHOWERS.
&&
.MARINE...
SHORT TERM /TODAY THROUGH SATURDAY/...UPDATED FORECAST TO INPUT
LATEST OBSERVED DATA RESULTING IN NO NOTICEABLE CHANGES TO THE
PREVIOUS FORECAST. HIGH PRESSURE KEEPS WINDS AND SEAS WELL BELOW
SCA LEVELS THRU SATURDAY.
LONG TERM...
SUN NIGHT - MON...SMALL CRAFT WINDS AND SEAS ARE LIKELY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
140 PM EDT FRI OCT 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 533 AM EDT FRI OCT 4 2013
TODAY...LATEST 09Z WATER VAPOR LOOP AND RUC ANALYSIS SHOW A
SHORTWAVE EXITING UPPER MI. MODELS INDICATE DNVA AND A TRANSITION TO
Q-VECT DIV IN THE WAKE OF THIS SHORTWAVE FOR THE REST OF THE
OVERNIGHT INTO MUCH OF DAY TODAY. THESE FACTORS ALONG WITH A LOSS OF
ANY MEANINGFUL WAA/ISENTROPIC ASCENT INTO AT LEAST EARLY AFTERNOON
SHOULD ALLOW ANY LINGERING SHRA TO DIE OUT TOWARD SUNRISE. ALREADY
SEEING A DIMINISHING TREND ON SHRA IN PAST HR OR TWO. EXPECT MUCH OF
TODAY TO STAY MOSTLY DRY AS MODELS INDICATE SHORTWAVE RDGG AND 5H
HEIGHT RISES OVER THE AREA IN RESPONSE TO POTENT STORM SYSTEM SLOWLY
ADVANCING FROM THE SRN/CNTRL PLAINS. THUS...HAVE DRASTICALLY TRIMMED
POPS BACK TO JUST SLIGHT CHC FOR MUCH OF THE FCST AREA. BROUGHT IN
LOW CHC (30 PCT) POPS LATE IN THE DAY ALONG THE WI BORDER AS WAA
DOES BEGIN TO INCREASE FROM THE SW.
TONIGHT...THE MODELS WERE IN REASONABLE AGREEMENT SHOWING INCREASING
300-310K ISENTROPIC ASCENT SPREADING FROM WEST TO EAST FROM LATE
EVENING INTO THE OVERNIGHT HRS TONIGHT IN RESPONSE TO CONTINUED SLOW
ADVANCE OF STORM SYSTEM THROUGH THE CENTRAL PLAINS. AS A RESULT...I
HAVE SLOWLY BROUGHT BACK LIKELY TO CATEGORICAL POPS FROM WEST TO
EAST MAINLY BETWEEN 06-12Z LATE TONIGHT. THERE MAY BE A PERIOD OF
HEAVY RAIN GIVEN THE FAVORABLE MOISTURE TRANSPORT AND PWAT VALUES TO
AROUND 1.5 INCHES. HOWEVER...CONVECTION SHOULD BE LIMITED AS BEST
MODEL MUCAPE VALUES AND NEGATIVE SHOWALTER INDICES STAY SOUTH
TONIGHT. EXPECT PCPN AMOUNTS GEENRALLY IN THE 0.20 TO 0.60 INCH
RANGE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 533 AM EDT FRI OCT 4 2013
NAM SHOWS A CLOSED 500 MB LOW OVER SD 12Z SAT WITH A RIDGE OVER THE
SERN U.S. WITH A RIDGE OVER THE WESTERN U.S. THIS CLOSED LOW WILL
CONTINUE TO MOVE SLOWLY EASTWARD THROUGH THE PERIOD THROUGH THE
UPPER GREAT LAKES. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE
WITH SOME DEEPER MOISTURE MOVING THROUGH THE CWA WITH A DRY SLOT
MOVING THROUGH ON SUNDAY. NAM SHOWS SOME ISENTROPIC LIFT AND
MOISTURE ON I300K-I315K SURFACES 12Z SAT WITH THE DRY SLOT MOVING IN
ON SUNDAY.
LOOKS LIKE A DECENT WIDESPREAD RAIN EVENT FOR THIS FORECAST PERIOD
AND WENT CATEGORICAL POPS ON SAT WITH A DRY SLOT MOVING THROUGH ON
SUN. KEPT IN SOME THUNDER CHANCES FOR SAT AND SAT NIGHT. WRAPAROUND
MOISTURE COMES INTO THE WEST ON SUN AND WENT CHANCE POPS THEN. DID
NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT RAISED LOW
TEMPERATURES SAT NIGHT A COUPLE DEGREES AS THEY LOOKED TOO COLD.
MAIN REASON IS NOT SURE THAT THE DRY SLOT WILL ALLOW CLEARING IN THE
LOWEST LEVELS FOR CLOUDS AND COLDER AIR DOES NOT ARRIVE UNTIL SUN.
IN THE EXTENDED...UPPER AIR PATTERN CONSISTS OF A 500 TROUGH OVER
THE EASTERN HALF OF THE U.S. WITH A RIDGE OVER THE ROCKIES 12Z MON.
THE RIDGE MOVES INTO THE PLAINS 12Z TUE WITH A TROUGH OVER THE
WESTERN U.S. THE TROUGH STAYS PUT 12Z WED WITH RIDGING OVER THE
GREAT LAKES REGION WHICH STAYS INTO THU. TEMPERATURES WILL CONTINUE
TO BE ABOVE NORMAL THROUGH THE PERIOD WITH UPPER RIDGING ALLOWING
DRY WEATHER TO CONTINUE. KEPT IN SLIGHT CHANCE POPS FOR MON AS UPPER
TROUGH MOVES AWAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 139 PM EDT FRI OCT 4 2013
HAVE WORSENING CONDITIONS THROUGH THE PERIOD AS A WARM FROM LIFTS N
INTO THE AREA TONIGHT INTO SATURDAY. WILL SEE PRECIPITATION MOVE IN
AT SOME POINT...BUT THAT IS FAIRLY UNCERTAIN. HOWEVER...WENT WITH
BEST GUESS FOR PRECIP TIMING IN THE TAFS. DID NOT LOWER VIS TOO MUCH
AS RAIN SHOULD BE MORE OF A STEADY RAIN...ALTHOUGH IT COULD BE
HEAVIER AT TIMES REDUCING VISIBILITIES FURTHER...BUT WAS TOO
UNCERTAIN TO GET INTO THESE DETAILS AT THIS TIME.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 533 AM EDT FRI OCT 4 2013
EXPECT EAST-NORTHEAST WINDS 15 TO 25 KTS EARLY THIS MORNING TO
INCREASE TO 20 TO 30 KT WITH A FEW GALE GUSTS OVER FAR WESTERN LAKE
SUPERIOR. LOOK FOR NE WINDS WILL INCREASE TO GALES TO 35 KTS OVER
FAR WRN LAKE SUPERIOR LATE TONIGHT/EARLY SATURDAY MORNING AND THEN
CONTINUE THROUGH SATURDAY EVENING. WINDS WILL THEN DIMINISH SAT
NIGHT/SUN AS THE LOW LIFTS ACROSS THE UPPER GREAT LAKES. DEPENDING
ON THE STRENGTH OF THE SFC LOW AS IT PASSES...WILL NEED TO WATCH FOR
A PERIOD OF STRONGER NW WINDS ON THE BACKSIDE OF THE SYSTEM SUNDAY
NIGHT INTO MON. WINDS WILL BE LIGHT MON NIGHT INTO TUESDAY AS HIGH
PRESSURE MOVES OVER THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 5 PM EDT /4 PM CDT/ THIS AFTERNOON TO 2 AM EDT
/1 AM CDT/ SUNDAY FOR LSZ162.
GALE WARNING FROM 11 PM THIS EVENING TO 11 PM EDT SATURDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...TITUS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
347 PM CDT FRI OCT 4 2013
.SYNOPSIS...
ISSUED AT 347 PM CDT FRI OCT 4 2013
IMPRESSIVE FALL SYSTEM TAKING CENTER STAGE ACROSS THE CENTRAL CONUS
TODAY. THE UPPER LOW IS NEAR THE NEB/CO/WY BORDER WITH AN IMPRESSIVE
PV/UPPER JET INDUCED DRY SLOT WORKING ACROSS NEB. ON THE NOSE OF THE
PV BOOT WE HAVE SEEN AN IMPRESSIVE BURST OF LIGHTNING NEAR THE
BADLANDS. AS THE JET/DRY SLOT CONTINUES TO PUSH EAST ACROSS NEB...IT
WILL BECOME AN INITIATION SOURCE FOR SEVERE CONVECTION OVER ERN NEB
BY 22Z.
AT THE SFC...A 1001 MB LOW WAS CENTERED OVER CENTRAL NEB WITH A COLD
FRONT BEGINNING TO SURGE SE ACROSS KS AND THE OK/TX PANHANDLES.
PERSISTENT CLOUD ACROSS MN/IA HAS PUT THE SKIDS ON THE NORTHWARD
PROGRESSION OF THE WARM FRONT...BUT CLEARING RECENTLY OVER NRN IA
HAS ALLOWED FOR THE WARM FRONT TO BECOME BETTER DEFINED. AT 3 PM
THIS BOUNDARY WAS LOCATED JUST NORTH OF THE I-80 CORRIDOR...
EXTENDING EAST TOWARD MILWAUKEE. PERSISTENT THUNDERSTORM
DEVELOPMENT ACROSS IOWA NORTH OF THE WARM FRONT HAS HELPED
REINFORCE IT TO THE SOUTH...AND ALSO AIDED IN THE MPX CWA
REMAINING DRY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 347 PM CDT FRI OCT 4 2013
BIGGEST CHANGE SEEN WITH THE FORECAST AS COMPARED TO LAST NIGHT IS
EVERYTHING IS A BIT SLOWER...SO DELAYING THE ONSET OF CATEGORICAL
POPS WAS THE BIGGEST CHANGE MADE TO THE FORECAST DURING THE DAY. THE
HRRR HAS BEEN FAIRLY STABLE WITH ITS DEPICTION OF THINGS TODAY AND
HAS SUPPORT FROM THE 04.12 HIRES-ARW...SO USED THESE TWO PIECES OF
GUIDANCE TO GUIDE THE POP FORECAST THIS PERIOD.
HAVE DELAYED BRINGING ANY LIKELY OR GREATER POPS INTO THE MPX AREA
UNTIL AFTER 00Z. THIS COINCIDES WITH A SIGNIFICANT INCREASE IN H85
MOISTURE TRANSPORT IN RESPONSE TO A LLJ INCREASING TO OVER 30 KTS
FROM IA BACK NW INTO ERN SODAK. MOISTURE CONVERGENCE AT THE NOSE OF
THE LLJ WILL LEAD TO A RAPID EXPANSION OF SHRA/TSRA ACTIVITY FROM SE
MN INTO WC MN BETWEEN 00Z AND 03Z AND LIFT NORTHEAST ACROSS THE AREA
TONIGHT. AFTER 03Z...AN OCCLUDED FRONT WILL START MOVING INTO SRN
MN...WHICH WILL ALREADY START DIMINISHING PRECIP COVERAGE ACROSS THE
SOUTH BY 6Z.
FOR THE SEVERE THREAT...THE SLOWER TIMING HAS CERTAINLY DIMINISHED
THE CHANCES THE MPX AREA WILL SEE SEVERE WEATHER...WITH THE MAIN
THREAT CORRIDOR LOOKING TO EXTEND FROM THE NEB/IA BORDER OVER TO
ABOUT I-35 IN CENTRAL IOWA. THE MAIN THREAT FOR THE MPX AREA LOOKS
TO BE DOWN ALONG THE I-90 CORRIDOR WHERE SOME ELEVATED LARGE HAIL
STORMS COULD BE SEEN.
FOR THE DAY SATURDAY...HOW THE DRY SLOT EVOLVES WILL HELP DETERMINE
WHERE WE SEE A REPEAT OF THE LAST TWO DAYS AND WHERE WE COULD SEE A
FAIR AMOUNT OF SUN. CURRENTLY...HAVE SKIES BEGINNING TO CLEAR AFTER
9Z IN SW MN...THEN SLOWLY TRACK THAT ENE DURING THE DAY. BY THE
AFTERNOON...BOTH THE GFS AND NAM ARE INDICATING THAT MUCH OF THE
TWIN CITIES COULD SEE MOSTLY SUNNY SKIES. ONLY CHANGES REALLY MADE
TO THE FORECAST FOR TOMORROW WAS TO DECREASE CLOUD COVER AMOUNT
ACROSS SRN MN AND DECREASE POPS OUTSIDE OF THE NRN AND ERN PERIPHERY
OF THE MPX CWA...AS MOST GUIDANCE SHOW WRAP AROUND PRECIP ON THE
WEST SIDE OF THE SYSTEM WAITING UNTIL 00Z TO MOVE BACK INTO WRN
MN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 347 PM CDT FRI OCT 4 2013
BY 00Z SUNDAY...THE SURFACE LOW WILL BE NEARLY STATIONARY AROUND
SIOUX FALLS SD. THE DRY SLOT WILL STILL BE FIRMLY IN PLACE OVER
MUCH OF SRN MN/WRN WI...WITH AN ARC OF RAIN ASSOCIATED WITH DECENT
FRONTOGENESIS EXTENDING FROM CENTRAL/ERN WI THROUGH CENTRAL/NRN
MN INTO THE EASTERN DAKOTAS. THE LOW WILL FILL AND EVENTUALLY WILL
BE SHOVED EASTWARD IN RESPONSE TO THE BUILDING RIDGE OVER THE
ROCKIES. THUS...THIS ARC OF RAIN WILL SLIDE EAST LATE SATURDAY
NIGHT THROUGH SUNDAY...ALTHOUGH IN A DIMINISHING PHASE AS IT DOES
SO. NONETHELESS...IT WILL BE CLOUDY AND RAINY/DRIZZLY UNDER THIS
BAND FOR MUCH OF THE DAY SUNDAY UNTIL MUCH DRIER AIR CAN FINALLY
PUSH IN FROM THE NORTHWEST SUNDAY EVENING.
RIDGING WILL BUILD OVER THE MIDWEST THROUGH THE REST OF THE LONG
TERM PERIOD AS A DEEP TROUGH DIGS DOWN THE WEST COAST. HIGH TEMPERATURES
WILL MODERATE QUICKLY BACK INTO THE 70S BY MIDWEEK/LATE WEEK WHICH
WILL BE 10 TO 15 DEGREES ABOVE AVERAGE. ANOTHER SIGNIFICANT STORM
SYSTEM WILL DEVELOP TO THE LEE OF THE ROCKIES THURSDAY NIGHT AND
TRACK MORE OR LESS NORTHWARD INTO THE DAKOTAS FRIDAY NIGHT. THIS
SHOULD KEEP THE MAJORITY OF THE AREA DRY THROUGH THE FORECAST
PERIOD...EXCEPT FOR PERHAPS WRN MN FRIDAY AFTERNOON. GFS AND ECMWF
ARE IN RATHER GOOD AGREEMENT AT THIS TIME RANGE SO FORECAST
CONFIDENCE IS HIGH FOR THE LONG TERM.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 113 PM CDT FRI OCT 4 2013
TOUGH CIG FORECAST FOR THIS AFTERNOON...AS MOISTURE OVERRUNNING THE
WARM FRONT TO THE SOUTH HAS HAD LIFR CIGS OVER SRN MN ALL
DAY...BUT THE DRY NE FLOW IN PLACE HAS BEEN SLOWLY BRINGING MVFR
CIGS SOUTHWEST INTO THE MPX TERMINALS. ALL BUT RWF SHOULD SEE A
PERIOD OF MVFR CIGS THIS AFTERNOON...BEFORE IFR/LIFR CONDITIONS
SPREAD BACK NORTH AFTER 00Z AS THE WARM FRONT LIFTS NORTH ACROSS
IOWA. TRENDED TIMING OF RETURN OF PRECIP ON THE HRRR AND COULD SEE
PRECIP ONSET IN TAFS NEEDING TO BE PUSHED BACK ANOTHER HOUR OR
TWO. A PRONOUNCED DRY SLOT WILL BE MOVING IN WITH THE WARM FRONT
LATE TONIGHT...WITH VFR AND MAINLY CLEAR SKIES OVER SRN MN SAT
MORNING...WITH THE MAIN QUESTION BEING HOW FAR NORTH DOES THE
CLEARING MAKE IT...ALONG WITH HOW QUICKLY DOES IT PUSH NORTHEAST.
KMSP...MOST AIRPORTS IN THE METRO HAVE GONE MVFR...SO CONFIDENT IN
CIGS RISING ABOVE 010...BUT WILL REMAIN BELOW 017. MAY SEE
OCCASIONAL SHOWERS THROUGH THE AFTERNOON...BUT ALL GUIDANCE IN
FAIRLY GOOD AGREEMENT WITH AN AREA OF SHRA AND A FEW TSRA MOVING
ACROSS THE FIELD BETWEEN 2Z AND 8Z. AFTER THIS MAIN ROUND MOVES
THROUGH...WILL LIKELY SEE OCCASIONAL BOUTS OF SHRA INTO SAT
MORNING BEFORE THE DRY SLOT MOVES IN A ENDS ANY PRECIP.
/OUTLOOK FOR KMSP/
SUN...MVFR OR LOWER. PERIODS OF -SHRA/-DZ. WINDS NW 10-15 KTS.
MON...VFR. WINDS W 5-10 KT.
TUE...VFR. WINDS S 5-10 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
333 PM CDT FRI OCT 4 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY AFTERNOON)
ISSUED AT 331 PM CDT FRI OCT 4 2013
MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE SHOWERS
EXPECTED TO DEVELOP LATE THIS AFTERNOON...SPREAD SLOWLY NWD
THROUGH THE NORTHLAND TONIGHT...WITH HEAVY RAIN POSSIBLE...AND
LINGER THROUGH MUCH OF THE DAY TOMORROW. STRONG NORTHEAST WINDS
OFF LAKE SUPERIOR ARE ALSO OF CONCERN IN THE SHORT TERM...AND A
WIND ADVISORY REMAINS IN EFFECT UNTIL 4 PM SATURDAY FOR LAKESHORE
AREAS AROUND THE HEAD OF THE LAKE.
DEEP CUT-OFF UPPER LOW CONTINUES TO BARREL EWD ACROSS THE SRN
ROCKIES INTO THE PLAINS THIS AFTERNOON...AS A SFC LOW STRENGTHENS
OVER CENTRAL KS AND A WARM FRONT EXTENDS EWD THROUGH IA INTO SRN
WI. LATEST SATELLITE IMAGERY SHOWS A WEDGE OF DRY AIR ALOFT PUSH
SW TO NE FROM CENTRAL KS INTO SRN MN...WHICH HAS ALLOWED MUCH OF
THE NORTHLAND TO REMAIN DRY THROUGH THE DAY. HOWEVER...THERE IS A
WEAK BAND OF MID-LEVEL F-GEN ACROSS NRN/CENTRAL WI/MN THAT IS
TRYING TO TRIGGER A FEW SHOWERS FROM BRAINERD MN TO LADYSMITH
WI...AS EVIDENT ON LATEST RADAR SCAN. CURRENT THINKING IS THAT
THIS LAYER OF F-GEN...FROM ROUGHLY 925 TO 700MB WILL BECOME
ENHANCED AT 850MB AS THE UPPER LOW TO THE SW CONTINUES TO WRAP UP
AND DRAW UP THE WARM/MOIST MID-LEVEL AIR FROM THE SOUTH. THE
INTERACTION OF THE WARM AIR WITH THE COLD AIR ON THE BACK SIDE OF
THE SYSTEM WILL ACT TO STRENGTHEN THE BAROCLINIC ZONE AND PROVIDE
ENOUGH LIFT TO PRODUCE RAIN SHOWERS ACROSS MUCH OF THE REGION AND
EVEN A FEW ISOLATED STORMS TO THE SOUTH TONIGHT.
THE FORCING FROM THE UPPER LOW AND AVAILABLE MOISTURE...PWATS
AROUND 1 INCH...SHOULD BE ENOUGH TO PRODUCE WIDESPREAD RAIN
SHOWERS WITH LOCALLY HEAVY RAIN POSSIBLE LATE TONIGHT. MOST OF THE
REGION COULD SEE AT LEAST A HALF INCH THROUGH SATURDAY
AFTERNOON...WITH NUMEROUS LOCATIONS POSSIBLY SEEING UPWARDS OF AN
INCH OR MORE. ADDITIONAL RAIN IS EXPECTED SAT NIGHT AND
SUNDAY...SO STORM TOTAL RAINFALL AMTS WILL LIKELY REACH OR EXCEED
2 INCHES IN SOME LOCATIONS. THE HIGHER AMTS ARE EXPECTED ACROSS
THE SRN COUNTIES.
VERY STRONG NE WINDS AROUND THE HEAD OF LAKE SUPERIOR...INCLUDING
THE TWIN PORTS...WILL BE THE OTHER IMPACT FROM THIS STORM. AS THE
SFC LOW STRENGTHENS AND MOVES EWD ACROSS SRN MN AND CENTRAL WI
TONIGHT AND TOMORROW...STRONG PRESSURE FALLS WILL OCCUR AHEAD OF
THE LOW AND COMBINE WITH A SFC HIGH OVER ONTARIO...AND SMALL-SCALE
FUNNELING THROUGH THE HEAD OF WRN LAKE SUPERIOR TO PRODUCE
SUSTAINED WINDS AROUND 20 TO 30 MPH AND GUSTS 35 TO 45 MPH FROM
THIS EVENING THROUGH SATURDAY AFTERNOON. THE WIND ADVISORY FOR THE
LAKE SHORE FROM SILVER BAY TO DULUTH/SUPERIOR TO BAYFIELD IS IN
EFFECT UNTIL 4 PM SATURDAY. THE REST OF THE NORTHLAND WILL SEE
BREEZY CONDITIONS AS WELL WITH GUSTS TO 25 MPH.
TEMPERATURES WILL REMAIN STEADY TONIGHT AS CLOUD COVER PERSISTS.
LOWS TONIGHT WILL ONLY FALL INTO THE 40S TO THE NORTH AND LOWER
50S SOUTH. HIGHS ON SATURDAY WILL NOT RISE TOO FAR FROM THE
MORNING LOWS. MID TO UPPER 40S ARE EXPECTED FOR MOST OF THE
REGION...WITH MID TO UPPER 50S POSSIBLE OVER PARTS OF NW WI.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 331 PM CDT FRI OCT 4 2013
THE REGION WILL CONTINUE TO BE UNDER THE INFLUENCE OF THE STRONG LOW
PRESSURE SYSTEM EARLY IN THE PERIOD. A BROAD AREA OF LOW AT THE
SURFACE WILL BE OVER SOUTHERN MINNESOTA/NORTHERN IOWA AT 00Z SUNDAY
AND IS FORECAST TO MOVE SLOWLY EAST/NORTHEAST SATURDAY NIGHT INTO
SUNDAY. THERE SHOULD BE A FAIRLY WIDESPREAD AREA OF RAIN OVER MUCH
OF OUR CWA SATURDAY NIGHT...WIT THE FAR NORTHWEST SEEING LOWEST
CHANCES. STRONG WINDS WILL CONTINUE OFF OF LAKE SUPERIOR...BUT
SHOULD BE A BIT LOWER THAN WHAT WE`LL EXPERIENCE TONIGHT INTO
SATURDAY. A DEFORMATION BAND OF RAIN/DRIZZLE WILL CONTINUE INTO
SUNDAY AND THAT WILL MOVE EAST SUNDAY NIGHT AND DIMINISH AS THE LOW
MOVES FURTHER TO THE EAST. WE HAVE LOWERING POPS AS SUNDAY AFTERNOON
AND SUNDAY NIGHT...BUT SEVERAL OF THE MODELS...ESPECIALLY THE 12Z
ECMWF...SHOW A SLOWER END TO THE DEFORMATION BAND OF LIGHT
RAIN/DRIZZLE. WE HELD ONTO CHANCES FOR RAIN A BIT LONGER...AND LATER
SHIFTS MAY NEED TO DO SO MORE.
WEAK HIGH PRESSURE BUILDS IN MONDAY AND WE KEPT THE FORECAST DRY.
THE ECMWF STILL HANGS ONTO SOME LIGHT PRECIP OVER NORTHWEST
WISCONSIN...AND A SMALL POP MAY HAVE TO BE ADDED IF THIS TREND
CONTINUES.
UPPER RIDGING SLOWLY BUILDS IN BEHIND THE DEPARTING DEEP SURFACE LOW
TUESDAY WITH THE FLOW ALOFT BECOMING SOUTHERLY AS THE RIDGE PASSES
BY THURSDAY/FRIDAY. A DRY PERIOD IS EXPECTED MONDAY THROUGH FRIDAY
FOR MOST AREAS.
TEMPERATURES WILL START OUT COOL SUNDAY WITH HIGHS ONLY FROM THE
UPPER FORTIES TO MID FIFTIES BUT WILL WARM AS THE UPPER RIDGE
APPROACHES. HIGHS BY WEDNESDAY ARE EXPECTED IN THE MIDDLE SIXTIES
FOR MOST AREAS...WITH MID-UPPER SIXTIES THURSDAY/FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1244 PM CDT FRI OCT 4 2013
A STRONG LOW PRESSURE SYSTEM WILL IMPACT THE REGION THROUGH THE
PERIOD WITH CONDITIONS GRADUALLY BECOMING WIDESPREAD MVFR/IFR. AS
OF EARLY THIS AFTERNOON...THERE WAS A MIX OF MVFR CEILINGS WITH
VFR. AS THE PERIOD PROGRESSES...CEILINGS WILL LOWER AND RAIN WILL
DEVELOP FROM SOUTH TO NORTH. THE BEST CHANCE FOR RAIN WILL OCCUR
AFTER 03Z THROUGH 15Z SATURDAY. MVFR/IFR VSBYS/CEILINGS WILL OCCUR
AS THE RAIN BECOMES MORE WIDESPREAD. THE RAP SUGGESTS IT WILL TAKE
LONGER FOR THE MVFR CEILINGS TO DEVELOP TODAY/THIS EVENING OVER NORTHERN
AREAS DUE TO A DRIER EASTERLY FLOW THERE. WE LEFT THE MENTION OF
THUNDERSTORMS OUT OF THE TAFS FOR NOW...BUT THERE COULD BE SOME
THAT DEVELOP...ESPECIALLY ACROSS KHYR/KBRD/KDLH.
STRONG NORTHEAST/EAST WINDS OFF OF LAKE SUPERIOR CAN BE EXPECTED
THROUGH THE TAF PERIOD. THE STRONGEST WINDS WILL OCCUR TONIGHT
INTO SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 48 49 43 50 / 90 80 90 60
INL 41 47 36 54 / 60 70 50 20
BRD 49 50 39 52 / 90 80 80 60
HYR 50 54 45 51 / 90 80 70 50
ASX 49 52 46 53 / 80 80 80 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 4 PM CDT SATURDAY FOR MNZ020-037.
WI...WIND ADVISORY UNTIL 4 PM CDT SATURDAY FOR WIZ001-002.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
LSZ143>147.
GALE WARNING UNTIL 4 PM CDT SATURDAY FOR LSZ143>147.
SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LSZ121-140>142-
148.
&&
$$
SHORT TERM...BJT
LONG TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
113 PM CDT FRI OCT 4 2013
.UPDATE...
ISSUED AT 113 PM CDT FRI OCT 4 2013
SIGNIFICANTLY CUT BACK ON POPS THIS AFTERNOON BASED ON CURRENT
RADAR TRENDS ALONG WITH THE HRRR...THEN DELAYED ARRIVAL OF THINGS
TONIGHT. HAVE SEEN DRY AIR WORK IN ON WATER VAPOR IMAGERY THIS
AFTERNOON...WHICH HAS CUT BACK ON THE PRECIP GENERATION. WILL
LIKELY BE AFTER 00Z WHEN THE LLJ BEGINS TO RE-INTENSIFY AND MOVE
NORTH ACROSS IOWA THAT THE MPX AREA SEES ANY SIGNIFICANT RAIN.
SYSTEM IN GENERAL IS TRENDING SLOWER THAN ORIGINALLY THOUGHT
OVERNIGHT...WITH EVEN THE SPC PULLING THE MODERATE RISK A BIT SW
WITH THEIR NOON UPDATE...KEEPING IT OUT OF THE MPX AREA.
AT 1 PM...THE WARM FRONT WAS STILL SOUTH OF I-80 IN IOWA AND ALL
INDICATIONS SHOW IT NOT ARRIVING INTO SRN MN UNTIL WELL AFTER
00Z. TRIED FOLLOWING TIMING OF THE HRRR AND 04.12 HIRES-ARW FOR
BRINGING IN NEXT ROUND OF THUNDERSTORMS TONIGHT...WHICH DO NOT LOOK
TO BEGIN IMPACTING SRN MN UNTIL 00Z AT THE EARLIEST BEFORE RAPIDLY
SPREADING NORTHEAST WITH THE LLJ. GIVEN THE SHEAR...WILL CERTAINLY
STILL BE A SEVERE THREAT FOR SOUTH CENTRAL MN FOR MAINLY LARGE
HAIL AND WIND TONIGHT...BUT FINDING IT HARD PRESSED TO SEE MUCH OF
SEVERE THREAT ONCE YOU START GOING NORTH OF A NEW ULM TO ROCHESTER
LINE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 432 AM CDT FRI OCT 4 2013
THE THREAT FOR SEVERE WEATHER EXISTS TODAY ACROSS PORTIONS OF
SOUTHERN MN AND WESTERN WI. NOTE: THERE WAS LITTLE CHANGE FROM
YESTERDAY`S DAY 2 MODERATE RISK TO THIS MORNING`S DAY 1 MODERATE
RISK AREA FROM THE STORM PREDICTION CENTER. THIS MORNING`S OUTLOOK
STILL HAS THE MODERATE RISK CLIPPING FAR SOUTHERN PORTIONS OF THE
FORECAST AREA.
THE FIRST ORDER OF BUSINESS WAS TO DROP TEMPERATURES TODAY AND
KEEP EVERYTHING IN THE 50S AND LOW 60S...EXCEPT FOR LOCATIONS
NEAR THE MN/IA BORDER WHERE THE WARM FRONT WILL LIKELY ARRIVE LATE
THIS EVENING. IT WILL BE ONE GLOOMY DAY NORTH OF THE FRONT. THE
THEME ALONG WITH THIS SYSTEM HAS BEEN A SLOWING TREND WITH
TIME...AND THE AVAILABLE 00-06Z RUNS ARE EVEN A BIT SLOWER YET AND
FARTHER TO THE SOUTHWEST WITH THE DEVELOPMENT OF THE SURFACE
CYCLONE. IN FACT...THE 500 MB LOW IS STILL DIGGING SOUTH EARLY
THIS MORNING AS EVIDENT BY THE WATER VAPOR LOOP AND LOCATION OF
THE HEIGHT FALLS. NOW EVENTUALLY /BETWEEN 12-18Z/ THE TROUGH IS
GOING TO BEGIN TO LIFT AND TAKE MORE OF AN E/NE TRACK. SEE THE DAY
1 SPC DISCUSSION: WWW.SPC.NOAA.GOV/PRODUCTS/OUTLOOK/DAY1OTLK.HTML
FOR A SLIGHTLY MORE THOROUGH DISCUSSION OF THE LARGE-SCALE
ENVIRONMENT AND OVERALL SEVERE WEATHER THREAT.
NO BIG OBJECTIONS TO THE POSITION OF THE SPC RISK AREAS. ONE COULD
MAKE AN ARGUMENT THAT THE SLIGHT RISK IS TOO FAR TO THE NORTH
GIVEN THE SLOWER EVOLUTION AND ALSO DUE TO THE FACT THAT
THUNDERSTORMS HAVE BEEN ONGOING ACROSS NE/IA FOR MOST OF THE NIGHT
AND HAVE PUSHED THE BOUNDARY WELL SOUTH. THE WARM FRONT IS GOING
TO HAVE TO COVER SOME SERIOUS GROUND TO GET BACK NEAR MN THIS
EVENING. FURTHERMORE...WE SHOULD CONTINUE TO BE SHROUDED IN CLOUD
COVER WITH A FEW BOUTS OF LIGHT RAIN OR DRIZZLE. THAT BEING
SAID...THE WARM SECTOR DOES SURGE NORTH AND APPROACHES THE SOUTH
TWIN CITIES METRO NEAR MIDNIGHT OFF THE NAM...THE GFS AND ECMWF
ARE SLOWER. THERE WILL STILL BE ELEVATED INSTABILITY IN SOUTHERN
MN...SO MARGINALLY SEVERE HAIL WOULD BE A THREAT LATE THIS EVENING
EVEN IF THE WARM FRONT IS SLOW TO RETURN. THE BIG CYCLONICALLY
LOPING HODOGRAPHS IN THE SOUTH ARE IMPRESSIVE BECAUSE MOST OF THE
CURVATURE IS IN THE LOWEST 2-3 KM WITH THE BACKED FLOW...SO I CAN
SEE THE TORNADO CONCERN IN IOWA WHERE THEY SHOULD RECOVER AND
GENERATE SOME INSTABILITY BY THE LATE AFTERNOON.
OBVIOUSLY...THUNDERSTORM INITIATION OR COVERAGE WILL NOT BE A
CONCERN WITH THIS SYSTEM. THE INCREASING UPPER JET /100+ KTS/ AND
GOOD THICKNESS DIFFLUENCE IS VACATING A LOT OF AIR ALOFT...JUST
BEGGING SURFACE PARCELS TO GO FOR A RIDE. THE QUESTION IN MN WILL
BE HOW FAST THE INSTABILITY IS ADVECTED INTO THE AREA. SPC`S
SIGNIFICANT SEVERE AREA IS PREDICATED ON THE DEVELOPMENT OF
SUPERCELLS /PREFERABLE DISCRETE/ IN IOWA LATE THIS AFTERNOON AND
EARLY EVENING - THAT`S HOW SOUTHERN MN WOULD END UP WITH SIG
SEVERE HAIL OR ANY TORNADOES AS WELL. IT HAPPENED IN EASTERN
NEBRASKA LAST NIGHT ALONG THE COLD FRONT BEFORE STORMS DEVELOPED A
COLD POOL. MORE LIKELY...THE CONVECTIVE MODE WILL BE EVOLVING
UPSCALE INTO MORE OF A WIND/SMALLER HAIL EVENT WHEN IT REACHES THE
FORECAST AREA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 432 AM CDT FRI OCT 4 2013
POTENT WOUND-UP LOW PRES CENTER WILL BE LOCATED IN ERN SD BY
DAYBREAK SAT MRNG WITH A LINE OF OR CLUSTERS OF TSTMS ONGOING IN
FAR ERN PORTIONS OF THE WFO MPX CWFA. THE PRECIP WILL ACTUALLY
COME TO A SHARP END SAT MRNG AS ALL MODELS ARE IN GOOD AGREEMENT
OF A WELL-DEFINED AND DEEP DRY SLOT ON THE SRN AND ERN SIDES OF
THE LOW PRES CENTER. THIS DRY SLOT WILL THEN PROCEED EWD THRU THE
DAY...BUT AS THE UPR LOW BEGINS TO OVERTAKE THE SFC REFLECTION...
THE DRY SLOT WILL GRADUALLY FILL UP WITH A RESURGENCE OF MOISTURE.
THIS WILL ALLOW FOR THE FORMATION OF ADDITIONAL SHOWERS SAT NIGHT
THRU MUCH OF SUN. NOT EXPECTING TSTMS ASIDE FROM FAR SE MN INTO SW
WI...BUT THE COLD POOL ALOFT WITH THIS SYSTEM COULD ALLOW FOR
SOME GRAUPEL /SMALL HAIL/ TO DEVELOP WITH SOME OF THE SHOWERS. THE
PRECIP WILL OVERALL SHIFT OFF TO THE E SUN NIGHT INTO MON...BEING
REPLACED BY DEEP RIDGING AND SFC HIGH PRES THAT WILL PREVENT
SYSTEMS OF ANY CONSEQUENCE FROM IMPACTING THE AREA. FROM MON
ON...A DRY FCST IS IN PLACE. AS FOR TEMPS...NOTICEABLE DIFFERENCES
E-W ACRS THE AREA WILL BE PRESENT ON SAT AS THE LOW PRES CENTER
MOVES ATOP THE REGION...WITH SFC FLOW NEARLY 180 DEGREES DIFFERENT
ACRS THE REGION. BY SUN...WITH THE LOW PRES CENTER E OF THE
AREA...MORE PRONOUNCED NLY FLOW WILL KICK IN NOTICEABLE CAA FOR
THE AREA. THE COOLDOWN WILL NOT LAST LONG AS RIDGING ALOFT WILL
MAKE FOR INCRG H5 HEIGHTS AND DEVELOPING SLY LLVL FLOW WHICH WILL
BRING IN MUCH WARMER TEMPERATURES FOR MON THRU THU...INCLUDING
HIGHS REACHING THE MID 70S IN SRN MN ON THU.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 113 PM CDT FRI OCT 4 2013
TOUGH CIG FORECAST FOR THIS AFTERNOON...AS MOISTURE OVERRUNNING THE
WARM FRONT TO THE SOUTH HAS HAD LIFR CIGS OVER SRN MN ALL
DAY...BUT THE DRY NE FLOW IN PLACE HAS BEEN SLOWLY BRINGING MVFR
CIGS SOUTHWEST INTO THE MPX TERMINALS. ALL BUT RWF SHOULD SEE A
PERIOD OF MVFR CIGS THIS AFTERNOON...BEFORE IFR/LIFR CONDITIONS
SPREAD BACK NORTH AFTER 00Z AS THE WARM FRONT LIFTS NORTH ACROSS
IOWA. TRENDED TIMING OF RETURN OF PRECIP ON THE HRRR AND COULD SEE
PRECIP ONSET IN TAFS NEEDING TO BE PUSHED BACK ANOTHER HOUR OR
TWO. A PRONOUNCED DRY SLOT WILL BE MOVING IN WITH THE WARM FRONT
LATE TONIGHT...WITH VFR AND MAINLY CLEAR SKIES OVER SRN MN SAT
MORNING...WITH THE MAIN QUESTION BEING HOW FAR NORTH DOES THE
CLEARING MAKE IT...ALONG WITH HOW QUICKLY DOES IT PUSH NORTHEAST.
KMSP...MOST AIRPORTS IN THE METRO HAVE GONE MVFR...SO CONFIDENT IN
CIGS RISING ABOVE 010...BUT WILL REMAIN BELOW 017. MAY SEE
OCCASIONAL SHOWERS THROUGH THE AFTERNOON...BUT ALL GUIDANCE IN
FAIRLY GOOD AGREEMENT WITH AN AREA OF SHRA AND A FEW TSRA MOVING
ACROSS THE FIELD BETWEEN 2Z AND 8Z. AFTER THIS MAIN ROUND MOVES
THROUGH...WILL LIKELY SEE OCCASIONAL BOUTS OF SHRA INTO SAT
MORNING BEFORE THE DRY SLOT MOVES IN A ENDS ANY PRECIP.
/OUTLOOK FOR KMSP/
SUN...MVFR OR LOWER. PERIODS OF -SHRA/-DZ. WINDS NW 10-15 KTS.
MON...VFR. WINDS W 5-10 KT.
TUE...VFR. WINDS S 5-10 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...MPG
SHORT TERM...CLF
LONG TERM...JPC
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
332 PM CDT Fri Oct 4 2013
.SHORT TERM: (Through Late Tonight)
Issued at 330 PM CDT Fri Oct 4 2013
Diurnal heating of the unseasonably warm and moist air mass has
resulted in weak instability across the region this afternoon.
However with little impetus, attempts for convective development
thus far across far southeast Missouri and southern Illinois have
been short-lived. The HRRR continues to indicate potential for spot
storms through sunset within the southern CWA so will continue with
some slight chance pops until then. Otherwise attention for tonight
turns to the strong storm system currently across the Plains region.
Anticipating that a squall line will evolve ahead of the attendant
cold front from Nebraska into Oklahoma this evening and this will
move eastward as the whole system progresses, with a swath of
precipitation also developing overnight in the wake of the front
in response to frontogenetical forcing and large scale ascent as a
short-wave rotates through the base of the progressive upper trof.
The main question then is just how far eastward all of this precipitation
will get before daybreak Saturday. The consensus of the model guidance
is that it may be after 12z before entering the CWA. At this time
I didn`t deviate dramatically from the previous forecast with the
leading edge just making it into the western CWA, but reduced pops
further east. Areas to the east of the main line will still be
under the threat of spotty warm advection activity overnight.
Glass
.LONG TERM: (Saturday through Next Friday)
Issued at 300 PM CDT Fri Oct 4 2013
By Saturday morning, surface cold front to be just west of St. Louis
metro area. As the occluded surface low, over southeastern SD,
associated with it slowly lifts out to the northeast, front to
slowly slide through rest of forecast area. Expect activity that
initially forms tonight to diminish by mid morning. Then trying to
determine when and where activity will refire as atmosphere becomes
more unstable by early afternoon is hard to pin down. With front
extending from Quincy to just west of St. Louis to near Monett by
18z Saturday, best chances of storms refiring and some severe
weather will be over southeast MO and southern IL. This matches well
with the day 2 outlook with this area in a slight risk. Another
forecast issue will be temperatures on Saturday. Will see a
non-diurnal trend as high temps will be reached early in the day
then either remain steady or fall during the afternoon hours.
Showers and isolated thunderstorms will taper off Saturday evening
before coming to an end. However, could see some scattered showers
on Sunday, especially during the afternoon hours as wrap around
clouds on back side of system moves through with an upper level
shortwave. So have added low chance pops over northeast MO/west
central IL with silent slight chance pops further south for now as
well as increase cloud cover through this period. Lows Saturday
night will be in the low 40s to low 50s with highs only rising
into the mid 50s to mid 60s on Sunday.
Sunday night could be our coldest night depending on how fast the
clouds clear out. For now will err on side of caution and keep more
clouds over the region with lows in the low to mid 40s. If clouds
completely clear out and winds remain light, could see even cooler
temps.
Beyond that, surface ridge moves off to the east with a slow warming
trend through the week. Temperatures to warm back up into the mid to
upper 70s by Thursday.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1209 PM CDT Fri Oct 4 2013
Diurnal cu continues to develop in response to heating of the
unseasonably warm and moist air mass across the region. We should
see scattered-broken cu with bases from 3000-4000 ft initially
rising slowly through the afternoon. There could also be some
isolated showers and thunderstorms, especially across the
southeast third of Missouri and southern Illinois but coverage and
uncertainty is too low to mention in the St. Louis area TAFS. The
diurnal cu should dissipate by/around sunset with high clouds
through the evening and then increasing low clouds overnight ahead
of an approaching cold front. There will be a 2-4 hour window with
shower and thunderstorms chances along/ahead of the front as it
progresses across the area on Saturday. Given how far this is into
the valid TAF period I have opted for -SHRA VCTS. In the wake of
the front it appears we should see a period of rain with MVFR
conditions previaling.
Specifics for KSTL:
Expecting see scattered-broken diurnal cu this afternoon. There could
also be some isolated showers and thunderstorms but coverage and
uncertainty is too low to mention in TAF. The diurnal cu should
dissipate by/around sunset with high clouds through the evening
and then increasing low clouds overnight ahead of an approaching
cold front. There will be a roughly 3 hour window with shower and
thunderstorms chances along/ahead of the front as it progresses
across the area on Saturday morning from around 16-19z. Given how
far this is into the valid TAF period I have opted for -SHRA VCTS.
Fropa is expected around 19z, and in the wake of the front it appears
we should see a period of rain with MVFR conditions previaling.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1239 PM CDT Fri Oct 4 2013
.UPDATE...
Issued at 1128 AM CDT FRI OCT 4 2013
Forecast thoughts for today and tonight have not changed much. Still
expect the cold front to sweep into eastern Kansas and far western
Missouri as a large upper level trough transits east from the Rocky
Mountains, bringing strong to potentially severe thunderstorms to
portions of the forecast area this evening. Timing on storms
continues to point at storms bubbling up and moving through extreme
eastern Kansas this evening --7PM to 9PM--. However, ahead of the
front storms are expected to continue bubbling up with isolated to
scattered showers or thunderstorms possible west of St Joseph and
Kansas City. Activity through the remainder of the morning and much
of the afternoon is not expected to be severe, though small hail and
locally heavy rain will be possible with the afternoon activity.
&&
.SHORT TERM...(Today through Saturday)
Issued at 414 AM CDT FRI OCT 4 2013
The next 48 hours will be a tale of two air masses, one more common
during mid-summer and the other more like late Fall. Much better
agreement between the models on timing of the cold front as well as
the placement of the upper level trough lends to a more confident
forecast and increase in PoPs with the frontal boundary.
For today a strong upper trough over the Great Basin centered just
east of SLC will lift northeast and into the Northern and Central
Plains by Saturday. Increasing downstream pressure falls have
already induced a surface low over northwest KS which will deepen
and likewise track northeast as the increasing dynamics aloft
overspread the Plains. A large warm sector exists east of the
Central Rockies with an impressive southwesterly low level jet in
excess of 50kts extending through OK, KS and western MO. A narrow
band of scattered elevated convection has formed as the right rear
quad of a 70kt wind max at 200mb encounters an axis of MLCAPES
around 1000 J/kg aligned near the low level jet axis. Earlier
versions of the HRRR and the 00Z NAM did a good job of forecasting
this activity. Expect this convection to spread across northwest MO
and northeast KS this morning before weakening towards the noon
hour. The afternoon hours should be mainly dry except for late in
the day over northwest MO. Temperatures will be impacted by the
increasing mid level cloud cover this morning and the convection
over northwest MO. However, should see clouds scatter out this
afternoon and allow good mixing to reach highs well into the 80s.
The weather will become quite active this evening as a convection
rapidly forms along a cold front over KS and southeast NE. This
boundary is attached to the low pressure center and will swing
eastward through the CWA. Given a moderate to highly unstable
airmass with over 2000 J/kg of MLCAPE plus the above noted h8 jet
and steepening mid level lapse rates due to cold air aloft
overspreading the region, the cap now in place will be lifted
allowing for rapid development of convection along the frontal
boundary. Expect this activity to form over eastern KS and southeast
NE by late afternoon and enter the far northwest CWA around 00Z.
Severe storms will be possible this evening mainly west of the I-35
corridor with large hail and damaging winds initially and as the
squall line matures evolving into a high wind threat. With
precipitable water values progged close to two standard deviations
above normal any training cells will produce very heavy rainfall.
This may be especially true after midnight as the NAM hints at post
frontal elevated convection forming due to increasing frontogenesis
within the 850-750mb layer.
While the cold front is expected to clear the CWA by Saturday
morning the post frontal stratiform rain with embedded thunder will
likely linger through Saturday morning over the eastern half of the
CWA. A major influx of cold air will be ushered into the CWA on
gusty westerly winds. Even with clearing skies the cold air
advection will overwhelm what little warming the sun will provide.
As such temperatures will struggle to warm much past 60 over the
western half of the CWA. Saturday night promises a need to turn on
your furnace as deep cold air advection continues with h8 temperatures
around 0C possible. Should see some lows fall into the upper 30s
across northern MO.
.LONG TERM...(Sunday through Thursday)
Issued at 414 AM CDT FRI OCT 4 2013
Model differences in the beginning of the extended period will make
for a tricky forecast on Sunday. The associated upper level trough,
that will be responsible for driving a cold front through the area
Friday night into Saturday morning, will develop a cut off low in
the base of the trough. This upper low will be a slow mover and by
Sunday is expected to be moving north of the CWA. However, models
are different as to the placement of the low. The EC and GFS
ensemble mean are the slowest and furthest south taking the upper
low across Iowa on the day Sunday. The operational GFS and GEM are
further north and more progressive with the upper low. The GEM and
operational GFS would lead to a dry and slightly warmer solution
whereas, the GFS ensemble and EC solution would be cooler with even
a chance for some light precipitation across northern Missouri. for
now, sided with the ALLBlend which is a compromise solution in
keeping conditions dry with highs in the upper 50 and lower 60s. As
surface high pressure builds in Sunday night temperatures will
bottom out in the lower 40s.
Beyond Sunday, the general trend amongst models is similar in
keeping conditions dry with a warming trend. Monday will be a
transitional day with northwest flow aloft behind the departing
upper level system. A return to southwesterly flow and plentiful
sunshine should allow highs to warm into the mid 60s to near 70.
Tuesday, an upper level ridge will begin to build into the area in
response to an upper level trough digging southward down the western
CONUS. This upper level ridge is expected to dominate the area as
well as much of the eastern half of the CONUS through Thursday.
Highs will warm through the middle part of the week with highs in
the mid to upper 70s by Thursday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1238 PM CDT FRI OCT 4 2013
Focus for the terminals over the next 24 hours is squarely on the
evening hours of today as a cold front, and associated thunderstorms,
blow through. Breezy southerly winds ahead of the front today will
keep much of the afternoon storm activity passing to the north of the
terminals. However, starting around 23Z to 00Z the front will be
nosing into northwest Missouri. Expectations are for activity to
reach the terminals between 01Z to 03Z this evening with a couple
hours of strong storms expected. These storms will likely bring
widely variable winds this evening, along with the threat of hail.
Strong storms should blow through before midnight, but low clouds
--MVFR-- with showers will likely spread across the terminals through
much of the early morning hours. Otherwise, winds behind the cold
front will be rather strong and gusty Saturday, but the current onset
time of these winds looks late enough in the period to warrant not
including in the TAF at this time.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Cutter
SHORT TERM...MJ
LONG TERM...73
AVIATION...Cutter
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1128 AM CDT Fri Oct 4 2013
.UPDATE...
Issued at 1128 AM CDT FRI OCT 4 2013
Forecast thoughts for today and tonight have not changed much. Still
expect the cold front to sweep into eastern Kansas and far western
Missouri as a large upper level trough transits east from the Rocky
Mountains, bringing strong to potentially severe thunderstorms to
portions of the forecast area this evening. Timing on storms
continues to point at storms bubbling up and moving through extreme
eastern Kansas this evening --7PM to 9PM--. However, ahead of the
front storms are expected to continue bubbling up with isolated to
scattered showers or thunderstorms possible west of St Joseph and
Kansas City. Activity through the remainder of the morning and much
of the afternoon is not expected to be severe, though small hail and
locally heavy rain will be possible with the afternoon activity.
&&
.SHORT TERM...(Today through Saturday)
Issued at 414 AM CDT FRI OCT 4 2013
The next 48 hours will be a tale of two air masses, one more common
during mid-summer and the other more like late Fall. Much better
agreement between the models on timing of the cold front as well as
the placement of the upper level trough lends to a more confident
forecast and increase in PoPs with the frontal boundary.
For today a strong upper trough over the Great Basin centered just
east of SLC will lift northeast and into the Northern and Central
Plains by Saturday. Increasing downstream pressure falls have
already induced a surface low over northwest KS which will deepen
and likewise track northeast as the increasing dynamics aloft
overspread the Plains. A large warm sector exists east of the
Central Rockies with an impressive southwesterly low level jet in
excess of 50kts extending through OK, KS and western MO. A narrow
band of scattered elevated convection has formed as the right rear
quad of a 70kt wind max at 200mb encounters an axis of MLCAPES
around 1000 J/kg aligned near the low level jet axis. Earlier
versions of the HRRR and the 00Z NAM did a good job of forecasting
this activity. Expect this convection to spread across northwest MO
and northeast KS this morning before weakening towards the noon
hour. The afternoon hours should be mainly dry except for late in
the day over northwest MO. Temperatures will be impacted by the
increasing mid level cloud cover this morning and the convection
over northwest MO. However, should see clouds scatter out this
afternoon and allow good mixing to reach highs well into the 80s.
The weather will become quite active this evening as a convection
rapidly forms along a cold front over KS and southeast NE. This
boundary is attached to the low pressure center and will swing
eastward through the CWA. Given a moderate to highly unstable
airmass with over 2000 J/kg of MLCAPE plus the above noted h8 jet
and steepening mid level lapse rates due to cold air aloft
overspreading the region, the cap now in place will be lifted
allowing for rapid development of convection along the frontal
boundary. Expect this activity to form over eastern KS and southeast
NE by late afternoon and enter the far northwest CWA around 00Z.
Severe storms will be possible this evening mainly west of the I-35
corridor with large hail and damaging winds initially and as the
squall line matures evolving into a high wind threat. With
precipitable water values progged close to two standard deviations
above normal any training cells will produce very heavy rainfall.
This may be especially true after midnight as the NAM hints at post
frontal elevated convection forming due to increasing frontogenesis
within the 850-750mb layer.
While the cold front is expected to clear the CWA by Saturday
morning the post frontal stratiform rain with embedded thunder will
likely linger through Saturday morning over the eastern half of the
CWA. A major influx of cold air will be ushered into the CWA on
gusty westerly winds. Even with clearing skies the cold air
advection will overwhelm what little warming the sun will provide.
As such temperatures will struggle to warm much past 60 over the
western half of the CWA. Saturday night promises a need to turn on
your furnace as deep cold air advection continues with h8 temperatures
around 0C possible. Should see some lows fall into the upper 30s
across northern MO.
.LONG TERM...(Sunday through Thursday)
Issued at 414 AM CDT FRI OCT 4 2013
Model differences in the beginning of the extended period will make
for a tricky forecast on Sunday. The associated upper level trough,
that will be responsible for driving a cold front through the area
Friday night into Saturday morning, will develop a cut off low in
the base of the trough. This upper low will be a slow mover and by
Sunday is expected to be moving north of the CWA. However, models
are different as to the placement of the low. The EC and GFS
ensemble mean are the slowest and furthest south taking the upper
low across Iowa on the day Sunday. The operational GFS and GEM are
further north and more progressive with the upper low. The GEM and
operational GFS would lead to a dry and slightly warmer solution
whereas, the GFS ensemble and EC solution would be cooler with even
a chance for some light precipitation across northern Missouri. for
now, sided with the ALLBlend which is a compromise solution in
keeping conditions dry with highs in the upper 50 and lower 60s. As
surface high pressure builds in Sunday night temperatures will
bottom out in the lower 40s.
Beyond Sunday, the general trend amongst models is similar in
keeping conditions dry with a warming trend. Monday will be a
transitional day with northwest flow aloft behind the departing
upper level system. A return to southwesterly flow and plentiful
sunshine should allow highs to warm into the mid 60s to near 70.
Tuesday, an upper level ridge will begin to build into the area in
response to an upper level trough digging southward down the western
CONUS. This upper level ridge is expected to dominate the area as
well as much of the eastern half of the CONUS through Thursday.
Highs will warm through the middle part of the week with highs in
the mid to upper 70s by Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 651 AM CDT FRI OCT 4 2013
Band of scattered showers and storms will affect far northwest MO
and northeast KS this morning, missing the Kansas City terminals and
may pass just to the west of KSTJ. MVFR stratus has formed in the
very humid airmass and latest BUFR soundings indicate these ceilings
will linger into the late morning before lifting.
Attention then turns to this evening when a band of strong/possibly
severe storms forms along a cold front. Models are in good agreement
with timing giving a boost to confidence. Expect showers and storms
to pass through the terminals during the evening hours. VFR ceilings
most likely except with the heavy showers which could lower ceilings
to MVFR with IFR visibilities. Frontal passage likely with initial
line of storms but convection will linger well past the passage of
the front.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Cutter
SHORT TERM...MJ
LONG TERM...73
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
315 PM MDT FRI OCT 4 2013
.DISCUSSION...
FRONT HAS BEEN HUNG UP JUST NORTH OF THE UNION COUNTY BORDER ALL
DAY...ALTHOUGH THE LOW CLOUDS ASSOCIATED WITH IT LAST NIGHT HAVE
DISSIPATED OVER SOUTHEAST AND EAST CENTRAL CO. RUC INDICATES THE
BOUNDARY TO PLUNGE SWD WITHIN THE NEXT 3 HOURS. IT ALSO INDICATES A
LITTLE MORE MOISTURE OVER PARTS OF THE NORTHEAST...AND RESULT HAS
BEEN TO UPGRADE SKY COVER TO PARTLY CLOUDY RATHER THAN CLEAR. STILL
MODELS NOT SUGGESTING A HUGE UPTICK IN DEWPOINTS THERE OVERNIGHT.
NORTHERLY WINDS ASSOCIATED WITH THE FRONT AS IT TRACKS THROUGH THE
PLAINS TO BE GUSTY BUT NOT QUITE AS STRONG AS INDICATED 24 HOURS
AGO.
AS FOR FREEZE HIGHLIGHTS...STILL SOME MARGINAL TEMPERATURES FOR
PORTIONS OF THE EAST CENTRAL AND RGV AS WELL AS THE SOUTH CENTRAL
HIGHLANDS. AND SATURDAY NIGHT TEMPERATURE GUIDANCE IS STILL LEANING
TOWARDS SOME WARMING. FORECAST BOUNDARY LAYER WINDS TONIGHT
NORTHEAST OVER THE PLAINS BUT FOR SATURDAY NIGHT THE GFS FORECASTS A
MORE WLY WIND FLOW IN THE LOWER LEVELS...AS OPPOSED TO THE NAM/S
LIGHT AND VRBL TO WEAK NW WINDS. FORECAST SOUNDINGS INDICATE
SOME STEEP INVERSIONS OFF THE DECK AT SELECTED POINTS SATURDAY NIGHT
BUT OVERALL THE SOUNDINGS EXHIBIT A WARMING TREND. THINK THERE
MAY BE SOME POINTS IN SHELTERED AREAS UNAFFECTED BY WIND THAT COULD
REACH THE MAGIC 32 OR SLIGHTLY BELOW OUTSIDE OF OUR FORECAST POINTS
TONIGHT...SO WENT AHEAD AND UPGRADED REMAINING EAST CENTRAL ZONES IN
THE WATCH. ALSO ADDED THE SOUTH CENTRAL HIGHLANDS TO THE WARNING
TONIGHT WITH FORECAST LOWS AGAIN HOVERING NEAR THE FREEZING MARK.
BASED ON THE ABOVE MODEL DISCUSSION...HAVE HELD OFF ON ISSUING
FURTHER FREEZE HIGHLIGHTS FOR SATURDAY NIGHT. WILL WAIT TO SEE WHAT
THE GUIDANCE DOES AS WELL AS WHAT MINS TONIGHT DO.
WINDS STILL TO TAPER OFF SATURDAY WITH A WARMING TREND SUNDAY
THROUGH TUESDAY. MODELS CONTINUE TO FOCUS ON AN UPPER LOW DIGGING
INTO THE SW US AROUND THE MID TO LATE WEEK PERIOD NEXT WEEK. WINDS
LOOK TO INCREASE TUESDAY AND MORESO WEDNESDAY WITH TEMPERATURES
FALLING THURSDAY/FRIDAY. WE NOW HAVE SOME MEAGER POPS FOR THE NORTH
AND WEST DURING THIS PERIOD...BUT MODELS NOT EXACTLY IN AGREEMENT
HOW THIS WILL PLAY OUT.
&&
.FIRE WEATHER...
CURRENT FIRE WEATHER HIGHLIGHTS ARE MARGINAL BUT WILL KEEP THEM
RUNNING THROUGH EVENT EXPIRATION. TUCUMCARI IS SHOWING NEAR RED FLAG
CONDITIONS WITH GUSTY WINDS AND TEEN HUMIDITY.
THE UPPER LOW WHICH IS CURRENTLY OVER THE CENTRAL ROCKIES AND GREAT
PLAINS WILL GRADUALLY SHIFT EASTWARD THE REST OF TODAY...TONIGHT
INTO SATURDAY. THE SURFACE WIND FLOW WILL GENERALLY RELAX AS A
RESULT ALTHOUGH A BACK DOOR COLD FRONT WILL PUSH ACROSS THE EASTERN
PLAINS TONIGHT AND INCREASE WINDS FOR A TIME. A CHILLY NIGHT IS IN
STORE WITH FREEZING TO NEAR FREEZING TEMPERATURES EXPECTED ACROSS
THE MAJORITY OF THE FIRE WEATHER FORECAST AREA. A HARD FREEZE WILL
BE FELT ACROSS THE NORTHERN AND WESTERN MOUNTAINS AND INCLUDE SOME
LOWLAND SITES AS WELL.
HIGH PRESSURE WILL BE IN CONTROL DURING THE WEEKEND. THE SURFACE
WIND FLOW WILL BE MUCH MORE RELAXED ALTHOUGH LOOK FOR SOME NORTHERLY
BREEZES ACROSS SOME WESTERN AND CENTRAL AREAS SATURDAY AFTERNOON.
THE FLOW ALOFT WILL BE MUCH WEAKER SO MAINLY SURFACE DRIVEN. FAIRLY
LIGHT WINDS FOR SUNDAY WITH JUST A FEW BREEZES ALONG INTERSTATE 25
BETWEEN LAS VEGAS TO RATON. MIXING HEIGHTS WILL BE ON THE LOWER SIDE
THANKS TO POST COLD FRONTAL INVERSION EFFECTS. THUS VENTILATION
RATES WILL BE LOWER. VENTILATION WILL BE THE POOREST ON SUNDAY.
EXPECTING A STRONG LOW LEVEL RADIATION INVERSION TO DEVELOP SATURDAY
NIGHT. THIS WILL BE ACCOMPANIED BY ADDITIONAL FREEZING TEMPERATURES
WITHIN BASINS AND VALLEYS. HIGH TEMPERATURES WILL BE WELL BELOW
NORMAL SATURDAY AND BE AROUND 5 TO 10 DEGREES BELOW NORMAL SUNDAY
AFTERNOON. HUMIDITY VALUES WILL BE NEAR SEASONABLE LEVELS ON
SATURDAY BUT LOWER ON SUNDAY WITH LOTS OF MINIMUM VALUES IN THE
TEENS. A MID LEVEL DRY INTRUSION PLUS A WARM UP WILL BE THE CATALYST
FOR LOWER HUMIDITY VALUES SUNDAY.
WEATHER MODELS REMAIN PERSISTENT WITH DEPICTING RIDGING ON MONDAY
AND THEN BREAKING DOWN OR SHIFTING EASTWARD ON TUESDAY. TEMPERATURES
WOULD CONTINUE TO WARM WHILE THE UPPER FLOW TURNS MORE SOUTHWESTERLY
ON TUESDAY. DRY CONDITIONS WOULD CONTINUE. VENTILATION RATES WILL
REMAIN ON THE LOWER SIDE MONDAY ALTHOUGH IMPROVE IN A FEW AREAS
COMPARED TO SUNDAY/S READINGS. TRANSPORT WINDS WILL INCREASE TUESDAY
SO THE VENTILATION WILL IMPROVE SIGNIFICANTLY THEN. NEAR TO ABOVE
NORMAL TEMPERATURES EXPECTED EARLY NEXT WEEK AND SURFACE HUMIDITY
WILL REMAIN ON THE LOWER SIDE. CURRENTLY HAVE SOME LOCALIZED
CRITICAL FIRE WEATHER GROWTH CONDITIONS DEPICTED WITHIN OUR GRIDDED
FORECAST TUESDAY AFTERNOON ACROSS THE NORTHEAST SO WILL BE
MONITORING THAT TREND.
THE LATEST LONG RANGE MODELS CONTINUE TO SHOW A BREEZY TO WINDY
PATTERN WEDNESDAY THROUGH FRIDAY AS ANOTHER PACIFIC TROUGH CROSSES
OVER THE INTERMOUNTAIN WEST. IT STILL APPEARS TO BE A DRY TROUGH
PASSAGE FOR THE FORECAST AREA. THUS...CANT RULE OUT SOME CRITICAL
FIRE WEATHER AREAS...MOST LIKELY FAVORING THE EAST...WHERE
TEMPERATURES WOULD BE ABOVE NORMAL FOR THE LONGEST. COOLING EXPECTED
ACROSS THE WEST ON THURSDAY AND SPREAD ACROSS THE ENTIRE AREA ON
FRIDAY. THIS AIRMASS APPEARS TO BE LESS CHILLY COMPARED TO THE
CURRENT ONE. VENTILATION WOULD BE QUITE HIGH WEDNESDAY AND THURSDAY
AND PROBABLY LOWER SOME ON FRIDAY. CONFIDENCE IS AT LEAST MODERATE
FOR THIS SCENARIO.
&&
.AVIATION...
18Z TAF CYCLE
TRADITIONAL COLD FRONT CURRENTLY FINISHING ITS SWEEP ACROSS THE
FORECAST AREA LATE THIS MORNING. THE WINDS ALOFT WILL BE WEAKENING
BUT THE SURFACE PRESSURE GRADIENT WILL REMAIN QUITE STRONG. LOOK
FOR STEADY ALTHOUGH SOMEWHAT DECREASING WIND BY LATE AFTERNOON.
GUST TO AROUND 30 KT WILL BE OBSERVED AT LVS AND TCC THROUGH MOST
OF THE AFTERNOON. THE MAIN BACK DOOR COLD FRONT WILL PLUNGE
SOUTHWARD TONIGHT AND EFFECT LVS/TCC AND ROW. THE MAIN EFFECT WILL
BE AN ABRUPT NORTHERLY WIND SHIFT. THE ATMOSPHERE IS PRETTY DRY SO
CIGS AND VIS SHOULD NOT BE AN ISSUE THE NEXT 24 HOURS.
50
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 27 58 27 66 / 0 0 0 0
DULCE........................... 22 55 23 63 / 0 0 0 0
CUBA............................ 23 55 26 65 / 0 0 0 0
GALLUP.......................... 20 58 21 67 / 0 0 0 0
EL MORRO........................ 19 55 21 65 / 0 0 0 0
GRANTS.......................... 21 57 22 68 / 0 0 0 0
QUEMADO......................... 25 62 25 68 / 0 0 0 0
GLENWOOD........................ 30 69 28 74 / 0 0 0 0
CHAMA........................... 20 52 26 60 / 0 0 0 0
LOS ALAMOS...................... 27 56 34 65 / 0 0 0 0
PECOS........................... 27 55 33 64 / 0 0 0 0
CERRO/QUESTA.................... 17 53 23 64 / 0 0 0 0
RED RIVER....................... 17 44 18 56 / 5 5 0 0
ANGEL FIRE...................... 20 53 20 62 / 5 0 0 0
TAOS............................ 19 56 21 65 / 0 0 0 0
MORA............................ 23 55 25 66 / 0 0 0 0
ESPANOLA........................ 21 60 28 70 / 0 0 0 0
SANTA FE........................ 23 55 30 65 / 0 0 0 0
SANTA FE AIRPORT................ 26 58 30 68 / 0 0 0 0
ALBUQUERQUE FOOTHILLS........... 32 57 37 68 / 0 0 0 0
ALBUQUERQUE HEIGHTS............. 36 60 36 69 / 0 0 0 0
ALBUQUERQUE VALLEY.............. 30 61 31 71 / 0 0 0 0
ALBUQUERQUE WEST MESA........... 30 60 32 71 / 0 0 0 0
LOS LUNAS....................... 33 63 31 71 / 0 0 0 0
RIO RANCHO...................... 31 61 33 71 / 0 0 0 0
SOCORRO......................... 36 65 37 73 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 30 56 37 67 / 0 0 0 0
TIJERAS......................... 30 58 38 67 / 0 0 0 0
MORIARTY/ESTANCIA............... 27 57 29 65 / 0 0 0 0
CLINES CORNERS.................. 28 56 33 65 / 0 0 0 0
GRAN QUIVIRA.................... 31 60 34 66 / 0 0 0 0
CARRIZOZO....................... 35 63 35 67 / 0 0 0 0
RUIDOSO......................... 39 57 32 62 / 0 0 0 0
CAPULIN......................... 20 54 22 67 / 0 0 0 0
RATON........................... 24 58 24 70 / 0 0 0 0
SPRINGER........................ 23 56 27 71 / 0 0 0 0
LAS VEGAS....................... 24 54 29 67 / 0 0 0 0
CLAYTON......................... 29 62 35 71 / 0 0 0 0
ROY............................. 27 59 33 69 / 0 0 0 0
CONCHAS......................... 33 62 33 73 / 0 0 0 0
SANTA ROSA...................... 33 63 34 73 / 0 0 0 0
TUCUMCARI....................... 34 64 34 75 / 0 0 0 0
CLOVIS.......................... 35 61 36 71 / 0 0 0 0
PORTALES........................ 35 63 35 72 / 0 0 0 0
FORT SUMNER..................... 36 64 34 74 / 0 0 0 0
ROSWELL......................... 43 68 36 74 / 0 0 0 0
PICACHO......................... 39 63 35 71 / 0 0 0 0
ELK............................. 40 60 34 65 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR THE FOLLOWING
ZONES...NMZ103-104-108.
FREEZE WARNING FROM 1 AM TO 9 AM MDT SATURDAY FOR THE FOLLOWING
ZONES...NMZ518-519-524-530>534.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
122 PM EDT FRI OCT 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL HANG ON OVER MUCH OF THE NORTH COUNTRY THROUGH
SATURDAY AS A FRONTAL SYSTEM REMAINS SUPPRESSED TO THE SOUTH.
CHANCES FOR SHOWERS WILL INCREASE SUNDAY AS A WARM FRONT LIFTS NORTH
ACROSS THE AREA. MORE RAIN CAN BE EXPECTED MONDAY AS LOW PRESSURE
AND ITS ASSOCIATED COLD FRONT MOVE THROUGH THE REGION. HIGH
PRESSURE THEN RETURNS FOR THE REMAINDER OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1249 PM EDT FRIDAY...HAVE UPDATED FCST TO MENTION ADDITIONAL
SHOWERS/SPRINKLES THIS AFTN...AS CRNT RADAR CONTS TO SHOW MORE
SHOWERS MOVING ACRS NORTHERN NY. MOST OF THIS PRECIP IS VERY LIGHT
WITH ONLY A COUPLE 0.01 OF AN INCH ANTICIPATED. WEAK EMBEDDED
SHORT WAVES RIDING ALONG SEVERAL SFC BOUNDARIES CONTS TO SUPPORT
THE MENTION OF POPS THRU THIS AFTN. HOWEVER...EVENTUALLY SFC HIGH
PRES LOCATED NEAR HUDSON BAY WL ADVECT DRIER AIR INTO OUR REGION
ON NORTHERLY WINDS TO DECREASE THE THREAT FOR LIGHT PRECIP BY THIS
EVENING. TEMPS WL RANGE MAINLY IN THE U50S TO M60S...VERY CLOSE TO
NORMAL.
HAVE INCREASED POPS ACRS OUR SOUTHERN VT ZNS TO LIKELY/LOW CAT (70
TO 80%) AND HIGH CHC (40 TO 50%) FOR PARTS OF THE SLV/WESTERN
DACKS FOR THIS MORNING. CRNT RADAR SHOWS A BAND OF LIGHT RAIN ACRS
SOUTHERN VT WITH LIGHT RAIN BEING OBSERVED AT VSF. IN
ADDITION...ANOTHER BAND OF LIGHT RAIN IS ENTERING THE SLV ATTM.
LATEST 12Z RAP 13 SHOWS BEST 850 TO 700MB LIFT ASSOCIATED WITH WAA
AND EMBEDDED 5H VORT WL BE ACRS OUR CENTRAL/SOUTHERN CWA THRU
16Z...BEFORE SHIFTING TO OUR EAST. MEANWHILE...PRECIP ACRS SLV IS
EXPECTED TO WEAKEN ACRS THE DACKS/WESTERN CPV BY 16Z...AS LLVL
ENVIRONMENT IS VERY DRY. OVERALL...NOT EXPECTING MUCH QPF>0.10"
THRU TODAY...WITH A GENERAL DECREASE IN AREAL COVERAGE OF PRECIP
THIS AFTN. TEMPS WL BE TRICKY AND HIGHLY DEPEND UPON CLOUD
CLOUD...WHICH WL PREVAIL MOST OF THE DAY...THEREFORE WL TREND
TEMPS DOWN SEVERAL DEGREES. THINKING U50S TO M60S MOST LOCATIONS.
PREVIOUS DISCUSSION...
WARM FRONT STRETCHING FROM NORTHERN MICHIGAN SOUTHEAST TO JERSEY
COASTAL WATERS AT THIS TIME. THIS FRONT WILL NOT ADVANCE MUCH
FURTHER NORTH TODAY BEFORE BECOMING STATIONARY. MEANWHILE...WEAK
COLD FRONT NORTH OF THE BORDER WILL DISSIPATE AS IT DEPRESSES
SOUTH. SKIES STILL MOSTLY CLEAR ACROSS A GOOD PORTION OF FORECAST
AREA AT THIS TIME...BUT CLOUDS TO THE WEST WILL OVERSPREAD THE
REGION TODAY WITH ANY FOG DISSIPATING BY MID MORNING. SOME SHOWERS
AND EVEN A LITTLE EMBEDDED THUNDER NORTH OF THE WARM FRONT AT THIS
TIME...BUT MOST OF THIS ACTIVITY IS EXPECTED TO PASS JUST SOUTH OF
BTV CWA TODAY. ANY SHOWERS ASSOCIATED WITH COLD FRONT TO THE NORTH
SHOULD DISSIPATE. SO BEST CHANCE FOR SEEING A FEW SHOWERS TODAY
WILL BE ACROSS SOUTHERN PORTION OF FORECAST AREA...WHERE 20-30
POPS PREFERRED. TEMPERATURES WILL BE A BIT COOLER THAN PREVIOUS
DAYS...WITH HIGHS IN THE MID 60S TO AROUND 70.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS OF 441 AM EDT FRIDAY...STATIONARY BOUNDARY WILL REMAIN SOUTH OF
THE FORECAST TONIGHT THROUGH SATURDAY NIGHT. FRONT MAY ACTUALLY BE
PUSHED FURTHER SOUTH TONIGHT THROUGH SATURDAY AS HIGH PRESSURE
ANCHORED OVER HUDSON BAY NOSES SOUTHEAST INTO NEW YORK/NEW ENGLAND
WHILE FLOW ALOFT CONTINUES FROM THE WEST-NORTHWEST. ALTHOUGH
SKIES ARE EXPECTED TO BE MOSTLY CLOUDY...IT SHOULD ALSO BE MAINLY
DRY TONIGHT THROUGH SATURDAY...WITH JUST A SLIGHT CHANCE SHOWERS
SOUTH.
CONDITIONS BEGIN TO CHANGE LATER SATURDAY NIGHT INTO SUNDAY AS
UPPER RIDGE SLOWLY SHIFTS EAST. THIS IS IN RESPONSE TO DEEP UPPER
LOW APPROACHING THE WESTERN GREAT LAKES SUNDAY. AS FLOW ALOFT
BECOMES MORE SOUTHWESTERLY...THIS WILL ALLOW WARM FRONT TO FINALLY
MAKE ITS PUSH NORTHWARD. SURGE OF DEEP MOISTURE...WITH PRECIPITABLE
WATER VALUES INCREASING TO 1.50 TO 1.75 INCHES...COMBINED WITH
BAND OF FRONTOGENESIS ASSOCIATED WITH WARM FRONT WILL RESULT IN AT
LEAST LIKELY POPS FOR LATE SATURDAY NIGHT AND ESPECIALLY DURING
THE DAY ON SUNDAY. CAN`T RULE OUT EMBEDDED THUNDER OVER WESTERN
ZONES SUNDAY AFTERNOON WITH SOME WEAK INSTABILITY INDICATED.
HIGH TEMPERATURES BOTH SATURDAY AND SUNDAY WILL BE MAINLY IN THE
MID60S TO NEAR 70...WITH LOWS IN THE 40S TONIGHT AND AROUND 50
SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 352 AM EDT FRIDAY...IT TOOK AWHILE...BUT MEDIUM RANGE
GUIDANCE OF THE GFS AND ECMWF HAVE FINALLY COME INTO GOOD
AGREEMENT IN REGARDS TO A POTENT LOW PRESSURE SYSTEM MOVING OUT
OF THE ROCKIES TODAY WHICH WILL AFFECT THE NORTHEAST THIS WEEKEND
INTO EARLY NEXT WEEK. FORECASTER CONFIDENCE IS INCREASING THAT
WE`LL SEE A MODEST RAIN EVENT LATE SUNDAY NIGHT THROUGH MONDAY.
YOU CAN READ MORE ABOUT THE EVOLUTION OF THIS SYSTEM THROUGH THE
WEEKEND IN THE SHORT TERM SECTION ABOVE...BUT THE SYNOPTIC SETUP TO
START THE EXTENDED PERIOD SUNDAY NIGHT WILL FEATURE A DEEP CLOSED
LOW SHIFTING NORTHEAST INTO THE GREAT LAKES REGION...WHILE AN UPPER
TROUGH ACROSS CENTRAL CANADA DIGS SOUTHEASTWARD TOWARDS THE
INTERNATIONAL BORDER. THESE TWO FEATURES EVENTUALLY PHASE TOGETHER
BY MIDDAY MONDAY WITH THE ATTENDING SURFACE WARM FRONT SHIFTING
NORTH OF THE BTV CWA SUNDAY NIGHT...AND THE COLD FRONT SWEEPING
THROUGH ON MONDAY. FOR SUNDAY NIGHT...HAVE BACKED OFF POPS A BIT AS
STRONG SOUTH/SOUTHWESTERLY FLOW IN THE WARM SECTOR SHOULD KEEP MUCH
OF THE AREA DRY...WITH THE EXCEPTION BEING ACROSS THE ST. LAWRENCE
VALLEY WHERE SHOWERS WILL BE LIKELY CLOSER TO THE COLD FRONT. ANOMALOUSLY
HIGH PWATS FOR OCTOBER BETWEEN 1.50 AND 1.75" ON THE NOSE OF A
STRONG 50KT 850MB SOUTHWESTERLY JET WILL ENHANCE DEEP LAYER LIFT
ALONG THE COLD FRONT LATE SUNDAY NIGHT THROUGH MONDAY AS IT TRACKS
ACROSS THE FORECAST AREA AND THUS...HAVE CONTINUED THE IDEA OF
LIKELY POPS FOR THIS TIME RANGE. ALSO ADDING MOISTURE INTO THE MIX
WILL BE THE REMNANTS OF TROPICAL STORM KAREN WHICH GETS ABSORBED
INTO THE UPPER FLOW DURING THIS TIME AS WELL. LATEST RUNS OF THE GFS
AND ECMWF DIFFER ONLY SLIGHTLY ON TIMING OF THE COLD FROPA...WITH
THE ECMWF LAGGING SLIGHTLY BEHIND. WITH THE RECENT BETTER
CONSISTENCY OF THE GFS AND CONTINUED TO LEAN TOWARDS THAT
SOLUTION...WHICH PUSHES THE FRONT EAST OF THE CONNECTICUT RIVER
VALLEY BY 00Z TUESDAY AS SURFACE HIGH PRESSURE BEGINS TO BUILD IN
FROM THE WEST. PARTLY TO MOSTLY CLOUDY SKIES PERSIST THROUGH MUCH OF
TUESDAY ON NORTHWEST UPPER FLOW...BUT BY TUESDAY NIGHT RIDGING ALOFT
BUILDS IN AND HIGH PRESSURE SHOULD DOMINATE THE NORTH COUNTRY`S
WEATHER THROUGH THE REMAINDER OF THE WEEK.
&&
.AVIATION /17Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...SATELLITE IMAGERY SHOWS QUITE A BIT OF
CLOUD COVER MOVING FROM WEST TO EAST ACROSS THE AREA THIS
AFTERNOON AND THIS WILL BE THE TREND THROUGH THE REMAINDER OF THE
PERIOD WITH MORE CLOUDS UPSTREAM OVER THE EASTERN GREAT LAKES
POISED TO MOVE INTO THE AREA AS WELL. HOWEVER...CEILINGS WILL
GENERALLY BE AT OR ABOVE 5000 FEET WITH SOME LOWERING OF THE
CLOUDS TONIGHT INTO THE 3000-5000 FOOT RANGE. NEVERTHELESS...LOOKING
AT VFR CEILINGS THOUGH THE ENTIRE PERIOD. SCATTERED LIGHT RAIN
SHOWERS WILL MOVE ACROSS THE AREA THROUGH 00Z TONIGHT...BUT
VISIBILITIES WILL REMAIN IN THE VFR CATEGORY. WINDS WILL GENERALLY
HAVE A NORTHERLY COMPONENT TO THEM...BUT SPEEDS WILL BE 10 KNOTS
OR LESS THROUGH THE PERIOD.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SATURDAY THROUGH 00Z SUNDAY...MAINLY VFR THOUGH CEILINGS WILL
CONTINUE TO LOWER THRU THE PERIOD. SLIGHT CHANCE FOR SHOWERS.
00Z SUNDAY THROUGH 00Z MONDAY...MAINLY VFR WITH INCREASING CHANCES
FOR MVFR RAIN SHOWERS AS A LOW PRESSURE SYSTEM APPROACHES FROM THE
WEST...ESPECIALLY ACROSS NORTHERN NEW YORK.
00Z MONDAY THROUGH 00Z TUESDAY...MVFR RAIN SHOWERS LIKELY AS A
COLD FRONT MOVES THROUGH THE REGION.
00Z TUESDAY THROUGH 00Z THURSDAY...VFR UNDER HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS/TABER
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...EVENSON/LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1254 PM EDT FRI OCT 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL HANG ON OVER MUCH OF THE NORTH COUNTRY THROUGH
SATURDAY AS A FRONTAL SYSTEM REMAINS SUPPRESSED TO THE SOUTH.
CHANCES FOR SHOWERS WILL INCREASE SUNDAY AS A WARM FRONT LIFTS NORTH
ACROSS THE AREA. MORE RAIN CAN BE EXPECTED MONDAY AS LOW PRESSURE
AND ITS ASSOCIATED COLD FRONT MOVE THROUGH THE REGION. HIGH
PRESSURE THEN RETURNS FOR THE REMAINDER OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1249 PM EDT FRIDAY...HAVE UPDATED FCST TO MENTION ADDITIONAL
SHOWERS/SPRINKLES THIS AFTN...AS CRNT RADAR CONTS TO SHOW MORE
SHOWERS MOVING ACRS NORTHERN NY. MOST OF THIS PRECIP IS VERY LIGHT
WITH ONLY A COUPLE 0.01 OF AN INCH ANTICIPATED. WEAK EMBEDDED
SHORT WAVES RIDING ALONG SEVERAL SFC BOUNDARIES CONTS TO SUPPORT
THE MENTION OF POPS THRU THIS AFTN. HOWEVER...EVENTUALLY SFC HIGH
PRES LOCATED NEAR HUDSON BAY WL ADVECT DRIER AIR INTO OUR REGION
ON NORTHERLY WINDS TO DECREASE THE THREAT FOR LIGHT PRECIP BY THIS
EVENING. TEMPS WL RANGE MAINLY IN THE U50S TO M60S...VERY CLOSE TO
NORMAL.
HAVE INCREASED POPS ACRS OUR SOUTHERN VT ZNS TO LIKELY/LOW CAT (70
TO 80%) AND HIGH CHC (40 TO 50%) FOR PARTS OF THE SLV/WESTERN
DACKS FOR THIS MORNING. CRNT RADAR SHOWS A BAND OF LIGHT RAIN ACRS
SOUTHERN VT WITH LIGHT RAIN BEING OBSERVED AT VSF. IN
ADDITION...ANOTHER BAND OF LIGHT RAIN IS ENTERING THE SLV ATTM.
LATEST 12Z RAP 13 SHOWS BEST 850 TO 700MB LIFT ASSOCIATED WITH WAA
AND EMBEDDED 5H VORT WL BE ACRS OUR CENTRAL/SOUTHERN CWA THRU
16Z...BEFORE SHIFTING TO OUR EAST. MEANWHILE...PRECIP ACRS SLV IS
EXPECTED TO WEAKEN ACRS THE DACKS/WESTERN CPV BY 16Z...AS LLVL
ENVIRONMENT IS VERY DRY. OVERALL...NOT EXPECTING MUCH QPF>0.10"
THRU TODAY...WITH A GENERAL DECREASE IN AREAL COVERAGE OF PRECIP
THIS AFTN. TEMPS WL BE TRICKY AND HIGHLY DEPEND UPON CLOUD
CLOUD...WHICH WL PREVAIL MOST OF THE DAY...THEREFORE WL TREND
TEMPS DOWN SEVERAL DEGREES. THINKING U50S TO M60S MOST LOCATIONS.
PREVIOUS DISCUSSION...
WARM FRONT STRETCHING FROM NORTHERN MICHIGAN SOUTHEAST TO JERSEY
COASTAL WATERS AT THIS TIME. THIS FRONT WILL NOT ADVANCE MUCH
FURTHER NORTH TODAY BEFORE BECOMING STATIONARY. MEANWHILE...WEAK
COLD FRONT NORTH OF THE BORDER WILL DISSIPATE AS IT DEPRESSES
SOUTH. SKIES STILL MOSTLY CLEAR ACROSS A GOOD PORTION OF FORECAST
AREA AT THIS TIME...BUT CLOUDS TO THE WEST WILL OVERSPREAD THE
REGION TODAY WITH ANY FOG DISSIPATING BY MID MORNING. SOME SHOWERS
AND EVEN A LITTLE EMBEDDED THUNDER NORTH OF THE WARM FRONT AT THIS
TIME...BUT MOST OF THIS ACTIVITY IS EXPECTED TO PASS JUST SOUTH OF
BTV CWA TODAY. ANY SHOWERS ASSOCIATED WITH COLD FRONT TO THE NORTH
SHOULD DISSIPATE. SO BEST CHANCE FOR SEEING A FEW SHOWERS TODAY
WILL BE ACROSS SOUTHERN PORTION OF FORECAST AREA...WHERE 20-30
POPS PREFERRED. TEMPERATURES WILL BE A BIT COOLER THAN PREVIOUS
DAYS...WITH HIGHS IN THE MID 60S TO AROUND 70.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS OF 441 AM EDT FRIDAY...STATIONARY BOUNDARY WILL REMAIN SOUTH OF
THE FORECAST TONIGHT THROUGH SATURDAY NIGHT. FRONT MAY ACTUALLY BE
PUSHED FURTHER SOUTH TONIGHT THROUGH SATURDAY AS HIGH PRESSURE
ANCHORED OVER HUDSON BAY NOSES SOUTHEAST INTO NEW YORK/NEW ENGLAND
WHILE FLOW ALOFT CONTINUES FROM THE WEST-NORTHWEST. ALTHOUGH
SKIES ARE EXPECTED TO BE MOSTLY CLOUDY...IT SHOULD ALSO BE MAINLY
DRY TONIGHT THROUGH SATURDAY...WITH JUST A SLIGHT CHANCE SHOWERS
SOUTH.
CONDITIONS BEGIN TO CHANGE LATER SATURDAY NIGHT INTO SUNDAY AS
UPPER RIDGE SLOWLY SHIFTS EAST. THIS IS IN RESPONSE TO DEEP UPPER
LOW APPROACHING THE WESTERN GREAT LAKES SUNDAY. AS FLOW ALOFT
BECOMES MORE SOUTHWESTERLY...THIS WILL ALLOW WARM FRONT TO FINALLY
MAKE ITS PUSH NORTHWARD. SURGE OF DEEP MOISTURE...WITH PRECIPITABLE
WATER VALUES INCREASING TO 1.50 TO 1.75 INCHES...COMBINED WITH
BAND OF FRONTOGENESIS ASSOCIATED WITH WARM FRONT WILL RESULT IN AT
LEAST LIKELY POPS FOR LATE SATURDAY NIGHT AND ESPECIALLY DURING
THE DAY ON SUNDAY. CAN`T RULE OUT EMBEDDED THUNDER OVER WESTERN
ZONES SUNDAY AFTERNOON WITH SOME WEAK INSTABILITY INDICATED.
HIGH TEMPERATURES BOTH SATURDAY AND SUNDAY WILL BE MAINLY IN THE
MID60S TO NEAR 70...WITH LOWS IN THE 40S TONIGHT AND AROUND 50
SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 352 AM EDT FRIDAY...IT TOOK AWHILE...BUT MEDIUM RANGE
GUIDANCE OF THE GFS AND ECMWF HAVE FINALLY COME INTO GOOD
AGREEMENT IN REGARDS TO A POTENT LOW PRESSURE SYSTEM MOVING OUT
OF THE ROCKIES TODAY WHICH WILL AFFECT THE NORTHEAST THIS WEEKEND
INTO EARLY NEXT WEEK. FORECASTER CONFIDENCE IS INCREASING THAT
WE`LL SEE A MODEST RAIN EVENT LATE SUNDAY NIGHT THROUGH MONDAY.
YOU CAN READ MORE ABOUT THE EVOLUTION OF THIS SYSTEM THROUGH THE
WEEKEND IN THE SHORT TERM SECTION ABOVE...BUT THE SYNOPTIC SETUP TO
START THE EXTENDED PERIOD SUNDAY NIGHT WILL FEATURE A DEEP CLOSED
LOW SHIFTING NORTHEAST INTO THE GREAT LAKES REGION...WHILE AN UPPER
TROUGH ACROSS CENTRAL CANADA DIGS SOUTHEASTWARD TOWARDS THE
INTERNATIONAL BORDER. THESE TWO FEATURES EVENTUALLY PHASE TOGETHER
BY MIDDAY MONDAY WITH THE ATTENDING SURFACE WARM FRONT SHIFTING
NORTH OF THE BTV CWA SUNDAY NIGHT...AND THE COLD FRONT SWEEPING
THROUGH ON MONDAY. FOR SUNDAY NIGHT...HAVE BACKED OFF POPS A BIT AS
STRONG SOUTH/SOUTHWESTERLY FLOW IN THE WARM SECTOR SHOULD KEEP MUCH
OF THE AREA DRY...WITH THE EXCEPTION BEING ACROSS THE ST. LAWRENCE
VALLEY WHERE SHOWERS WILL BE LIKELY CLOSER TO THE COLD FRONT. ANOMALOUSLY
HIGH PWATS FOR OCTOBER BETWEEN 1.50 AND 1.75" ON THE NOSE OF A
STRONG 50KT 850MB SOUTHWESTERLY JET WILL ENHANCE DEEP LAYER LIFT
ALONG THE COLD FRONT LATE SUNDAY NIGHT THROUGH MONDAY AS IT TRACKS
ACROSS THE FORECAST AREA AND THUS...HAVE CONTINUED THE IDEA OF
LIKELY POPS FOR THIS TIME RANGE. ALSO ADDING MOISTURE INTO THE MIX
WILL BE THE REMNANTS OF TROPICAL STORM KAREN WHICH GETS ABSORBED
INTO THE UPPER FLOW DURING THIS TIME AS WELL. LATEST RUNS OF THE GFS
AND ECMWF DIFFER ONLY SLIGHTLY ON TIMING OF THE COLD FROPA...WITH
THE ECMWF LAGGING SLIGHTLY BEHIND. WITH THE RECENT BETTER
CONSISTENCY OF THE GFS AND CONTINUED TO LEAN TOWARDS THAT
SOLUTION...WHICH PUSHES THE FRONT EAST OF THE CONNECTICUT RIVER
VALLEY BY 00Z TUESDAY AS SURFACE HIGH PRESSURE BEGINS TO BUILD IN
FROM THE WEST. PARTLY TO MOSTLY CLOUDY SKIES PERSIST THROUGH MUCH OF
TUESDAY ON NORTHWEST UPPER FLOW...BUT BY TUESDAY NIGHT RIDGING ALOFT
BUILDS IN AND HIGH PRESSURE SHOULD DOMINATE THE NORTH COUNTRY`S
WEATHER THROUGH THE REMAINDER OF THE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 12Z SATURDAY...OUTSIDE OF SOME LINGERING FOG AT KSLK AND
KMPV THROUGH 14Z...GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH
THE PERIOD WITH MID CLOUDS FROM 5-10 KFT STREAMING ACROSS THE
AREA. COULD SEE A FEW SHOWERS MAINLY ACROSS SOUTHERN VT AND
NORTHERN NEW YORK...BUT SHOULDN`T IMPACT FLIGHT CONDITIONS. AFTER
00Z WHEN CIGS LOWER FURTHER TO 4-6 KFT BUT SHOULD REMAIN VFR.
WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...
12Z SATURDAY THROUGH 00Z SUNDAY...MAINLY VFR THOUGH CEILINGS WILL
CONTINUE TO LOWER THRU THE PERIOD. SLIGHT CHANCE FOR SHOWERS.
00Z SUNDAY THROUGH 00Z MONDAY...MAINLY VFR WITH INCREASING CHANCES
FOR MVFR RAIN SHOWERS AS A LOW PRESSURE SYSTEM APPROACHES FROM THE
WEST...ESPECIALLY ACROSS NORTHERN NEW YORK.
00Z MONDAY THROUGH 00Z TUESDAY...MVFR RAIN SHOWERS LIKELY AS A
COLD FRONT MOVES THROUGH THE REGION.
00Z TUESDAY THROUGH 00Z WEDNESDAY...VFR UNDER HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS/TABER
SHORT TERM...RJS
LONG TERM...LAHIFF
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
156 PM EDT FRI OCT 4 2013
.SYNOPSIS...
HIGH PRESSURE CONTINUES TO AFFECT THE WEATHER OF THE REGION THROUGH
THE DAY SUNDAY. INCREASING MOISTURE AHEAD OF BOTH A COLD FRONT...AND
TROPICAL STORM KAREN...SPREADS INTO THE REGION FOR THE START OF THE
NEXT WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1007 AM FRIDAY...
WATER VAPOR IMAGERY SHOWED A MODEST MID-LEVEL SHORTWAVE MOVING
ACROSS CENTRAL NORTH CAROLINA BUT WITH DRY AIR ALOFT. AT THE
SURFACE...THE PIEDMONT TROUGH IS IN PLACE...WITH DEW POINTS IN THE
60S. DESPITE THE AVAILABLE LOW-LEVEL MOISTURE AND MOISTURE AT 850MB
ON THE 12Z UPPER-AIR ANALYSIS...DRY AIR ALOFT AND CAPPING SHOULD
PRECLUDE DEEP CONVECTION. THE AMDAR SOUNDINGS EARLY THIS MORNING AT
BOTH GSO AND RDU COMPARED VERY WELL WITH THE RAP FORECAST SOUNDINGS
AT THE SAME TIME...SHOWING SOME COOLING THAT TOOK PLACE ALOFT AROUND
700MB BUT STILL WITH ENOUGH OF A CAP...AND VERY MODEST WARMING
BEHIND THE MID-LEVEL SHORTWAVE FORECAST THIS AFTERNOON...THAT THE
CHANCES FOR ANY SHOWERS APPEAR PRETTY REMOTE. ALTHOUGH NAM MOS
GUIDANCE HAS LOW 20S CHANCES FOR SHOWERS AT KGSO AND KTDF...ALL
OTHER GUIDANCE IS DRY...AND THE LATEST HRRR WRF IS DRY AS WELL.
COULD BE A FEW CLOUDS DRIFTING IN FROM THE WEST AND NORTHWEST DUE TO
SOME DEEPER CONVECTION IN DIRECT VICINITY OF THE HIGHER ELEVATIONS
LATE IN THE DAY...BUT OTHERWISE...CONSIDERABLE SUNSHINE EXPECTED
THIS AFTERNOON UNDER 700MB SUBSIDENCE. MLCAPE BARELY REGISTERS...
WITH A MODIFIED KGSO SOUNDING SHOWING AN MLCAPE IN LOW DOUBLE
FIGURES. HIGH TEMPERATURES WILL REMAIN IN THE MID TO UPPER 80S...IN
CONJUNCTION WITH 1000-850MB THICKNESSES WHICH COINCIDE WELL WITH MOS
GUIDANCE HIGHS...ALONG WITH PERSISTENCE FROM THURSDAY. -DJF
TONIGHT...LOW LEVEL SLY FLOW WILL ADVECT MOISTURE INTO THE REGION.
THIS WILL BE EVIDENT IN SFC DEWPOINTS NEAR 60-LOWER 60S. WITH
MAINLY CLEAR SKIES ALOFT AND A LIGHT-NEAR CALM WIND REGIME...MAY SEE
AREAS OF FOG DEVELOP WELL AFTER MIDNIGHT. MIN TEMPS UPPER 50S TO
LOWER 60S. -WSS
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 314 AM FRIDAY...
SATURDAY...MID-UPPER LEVEL RIDGE OVER THE SE U.S. AND A SFC HIGH
ANCHORED OFFSHORE WILL RESULT IN ANOTHER MOSTLY SUNNY AND WARM DAY.
THICKNESSES STEADY IN THE 1410-1415M SO EXPECT SIMILAR HIGHS TEMPS
COMPARED TO TODAY....MID-UPPER 80S (POSSIBLY 90 IN THE SANDHILLS).
WITH SFC DEWPOINTS IN THE LOWER 60S...IT WILL START FEEL A BIT
UNCOMFORTABLE TO MOST FOLKS.
BY SATURDAY NIGHT...T.C. KAREN WILL BE LURKING OFF THE NORTHERN GULF
OF MEXICO COAST. MEANWHILE A DEEP UPPER LEVEL LOW WILL BE OVER THE
CENTRAL PLAINS. THESE WEATHER FEATURES WILL SERVE TO WEAKEN THE
UPPER LEVEL RIDGE OVER THE SE U.S. THIS PROCESS WILL ALLOW LOW AND
UPPER LEVEL MOISTURE TO INCREASE ACROSS CENTRAL NC SATURDAY NIGHT
INTO SUNDAY. WITH SFC DEWPOINTS SOLIDLY IN THE LOWER 60S AND SKIES
MOSTLY CLEAR TO START...AREAS OF FOG SHOULD DEVELOP ONCE AGAIN. MIN
TEMPS MAINLY NEAR 60-LOWER 60S.
SUNDAY...EXPECT TO SEE AN INCREASE IN CLOUDINESS AS MID-UPPER LEVEL
WINDS BACK IN RESPONSE TO THE EWD ADVANCING UPPER LEVEL LOW MOVING
INTO THE WESTERN GREAT LAKES. THIS WEATHER SYSTEM WILL ALSO CAUSE
T.C. KAREN TO LIFT NEWD INTO THE SE U.S. LATE SUNDAY-SUNDAY NIGHT.
THE AIR MASS OVER CENTRAL NC WILL QUICKLY BECOME MOISTURE
LADEN...ESPECIALLY IN THE WEST. INCREASING DIVERGENCE ALOFT COUPLED
WITH WEAK ISENTROPIC UPGLIDE WILL SUPPORT THE DEVELOPMENT OF A FEW
SHOWERS LATE IN THE DAY...MAINLY OVER THE SW THIRD OF THE FORECAST
AREA.
EXTENT/THICKNESS OF CLOUD COVER BY SUNDAY AFTERNOON WILL PLAY A ROLE
IN AFTERNOON TEMPS. BELIEVE THAT THERE WILL BE ENOUGH PARTIAL SUN
SUNDAY AFTERNOON TO WARM TEMPS BACK INTO THE MID 80S OVER MOST OF
THE REGION.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 235 AM FRIDAY...
...KAREN`S REMNANTS WILL AFFECT NC SUNDAY NIGHT THROUGH TUESDAY
MORNING...
MODEL SOLUTIONS CONCERNING FINER DETAILS OF THE TRACK OF TROPICAL
CYCLONE KAREN AND ITS INTERACTION WITH AN APPROACHING COLD FRONT ARE
STILL ON THE LOWER END OF THE CONFIDENCE SCALE. ON THE OTHER
HAND...WHILE IT IS TOO EARLY TO PINPOINT A NARROW TIME WINDOW OF
HEAVY RAIN...A SIGNIFICANT AND WIDESPREAD BENEFICIAL RAIN EVENT
APPEARS LIKELY AS THE TROPICAL MOISTURE PLUME FROM KAREN SPREADS
INTO THE WEST SUNDAY AFTERNOON/EVENING...AND OVER MOST OF CENTRAL
NORTH CAROLINA BY MONDAY MORNING. WIDESPREAD RAINFALL AMOUNTS OF >1
INCH ARE A GOOD BET...AND A STRIPE OF 2+ INCHES CAN REASONABLY BE
EXPECTED ALONG AND WEST OF THE EVENTUAL TRACK...WHICH IS NOT CERTAIN
AT THIS POINT BUT HAS A GOOD CHANCE OF BEING OVER OR JUST SKIRTING
THE CWFA. THE POTENTIAL FOR VERY HEAVY SHOWERS WITH HIGH RAINFALL
RATES AND TRAINING CELLS WOULD PRODUCE A THREAT FOR FLASH
FLOODING...WHICH WOULD BE MORE LIKELY IN MORE URBANIZED AREAS.
CHANGES TO THE FORECAST AT THIS POINT ARE TO INCREASE POPS LATER
SUNDAY NIGHT AND MONDAY...WITH A NUDGE UPWARDS IN THE AMOUNTS AS
WELL. WILL CONTINUE PROGRESSIVE TAPERING OFF OF THE PRECIP MONDAY
NIGHT...WITH LINGERING SHOWERS IN THE NORTHEAST ON TUESDAY. HIGH
TEMPS ON MONDAY AND TUESDAY WILL BE IN THE 70S...PERHAPS SOME NEAR
80 READINGS IN THE EAST MONDAY IF PRECIP SPREADS IN A LITTLE SLOWER.
MODEL DIVERGENCE IS MORE EVIDENT AS TO LATER DEVELOPMENTS DUE TO
DIFFERENCES IN THE EVOLUTION OF A MID-LATE WEEK CUTOFF LOW AND A
REX-ISH BLOCKING PATTERN. THE ECMWF AND GFS TAKE DIFFERING ROUTES TO
ARRIVE AT A RATHER SIMILAR LOOKING PATTERN. ECMWF DEVELOPS THE
CUTOFF TO THE WEST AND MEANDERS IT NORTHEAST AND NEARLY OVERHEAD...
WHILE THE GFS DEVELOPS THE CUTOFF OVER NORTHEAST NC AND RETROGRADES
IT WEST AND OVERHEAD. AT THIS EARLY JUNCTURE WILL HOLD OFF MAKING
ANY CHANGES TO THE ONGOING DRY AND SLIGHTLY BELOW SEASONABLE
FORECAST BEYOND TUESDAY AS WE AWAIT LATER MODEL CONSENSUS.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 155 PM FRIDAY...
VFR CONDITIONS CONTINUE INTO THE OVERNIGHT HOURS. LATE TONIGHT...
SOME AREAS OF FOG ARE ANTICIPATED...WITH THE HIGHEST PROBABILITY...
AND CORRESPONDINGLY THE LOWER EXPECTED VISIBILITIES...TOWARD KRWI
AND KFAY. SREF MODEL PROBABILITIES OF VISIBILITIES BELOW 3 MILES ARE
HIGHEST TOWARD THOSE TAF SITES LATE TONIGHT INTO EARLY SATURDAY.
SURFACE WINDS WERE FORECAST MAINLY WITH A GENERAL SOUTH OR SOUTHWEST
DIRECTION...BUT WITH HIGH PRESSURE DIRECTLY OVERHEAD...THERE IS THE
POTENTIAL OF A MORE VARIABLE DIRECTION ESPECIALLY EARLY SATURDAY...
WITH THE NAM MODEL SUGGESTIVE OF A BRIEF PERIOD OF LIGHT NORTHEAST
WIND BEFORE 15Z SATURDAY.
BEYOND THE 18Z VALID TAF PERIOD...ONE AVIATION IMPACT IS AREAS OF
FOG AND LOW CLOUDS...WITH GUIDANCE STRONGLY HINTING AT THIS
THROUGHOUT CENTRAL NORTH CAROLINA LATE SATURDAY NIGHT AND SUNDAY
MORNING. DEPENDING ON THE AMOUNT OF CLOUD COVER IN ADVANCE OF
INCREASING MOISTURE AHEAD OF AN APPROACHING COLD FRONT AND THE
INFLUENCE OF KAREN...SUB-VFR CONDITIONS ARE POSSIBLE AGAIN LATE
SUNDAY NIGHT AND MONDAY MORNING. IN ADDITION...RAIN CHANCES INCREASE
INTO MONDAY...CONTINUING INTO TUESDAY...WITH CORRESPONDING AREAS OF
SUB-VFR CONDITIONS WHICH SHOULD BE NUMEROUS. WIDESPREAD VFR
CONDITIONS ARE LIKELY TO RETURN BY WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/WSS
SHORT TERM...WSS
LONG TERM...MLM
AVIATION...DJF
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
101 PM CDT FRI OCT 4 2013
.UPDATE...
18Z AVIATION DISCUSSION UPDATED BELOW.
SCATTERED/NUMEROUS SHOWERS WERE LIFTING NORTH ACROSS MAINLY
CENTRAL AND NORTH CENTRAL SOUTH DAKOTA LATE THIS MORNING.
ALSO...REPORTS IN WESTERN CORSON OF THE RAIN CHANGING OVER TO
SNOW. THE LATEST HRRR RUN SHOWS MORE SHOWERS/THUNDERSTORMS
DEVELOPING THIS AFTERNOON/EARLY EVENING ALONG DRY SLOT LIFTING
NORTHWARD IN THE DEEPENING UPPER LOW PRESSURE AREA. ADDED SNOW OR
RAIN/SNOW TO THE FAR WESTERN COUNTIES THROUGH THE AFTERNOON. THE
OTHER ISSUE IS THE STRONG WINDS ALREADY OCCURRING. THE LATEST
MODEL RUNS AND GUIDANCE SHOW THESE STRONG WINDS CONTINUING THROUGH
THE AFTERNOON AND NIGHT. WINDS MAY BE CLOSE TO HIGH WINDS AT TIMES.
WILL LEAVE WIND ADVISORY GOING THROUGH THE NIGHT AND MAY HAVE TO
EXTEND THIS EVEN THROUGH SATURDAY. NOT MUCH CHANGE IN TEMPERATURES
THROUGH THE AFTERNOON WITH CLOUD COVER AND PRECIPITATION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
HEADLINES OVER THE NEXT 24 TO 30 HOURS WILL BE THE MAIN FORECAST
CHALLENGE.
MODELS ARE IN A REASONABLE AGREEMENT THIS MORNING WITH THE
HANDLING OF THE FIRST SNOWSTORM OF THE SEASON. ISENTROPIC UPGLIDE
IS CURRENTLY ONGOING OVER WESTERN SOUTH DAKOTA WHERE WIDESPREAD
LIGHT TO MODERATE RAIN IS OCCURRING. SO FAR ONLY THE HIGHER
TERRAIN AREAS OF THE BLACK HILLS AND EASTERN WYOMING HAS
TRANSITIONED OVER TO ALL SNOW. WITH LIMITED CAA...WAA AT H7...NOT
TOO SURPRISED TO SEE A SLOW TRANSITION OVER TO SNOW. THE 0Z MODEL
RUNS OF THE GFS/NAM/HI-RES ARW ALL SUGGEST LITTLE TO NO SNOW FOR
LOCATIONS ALONG AND EAST OF THE MISSOURI RIVER FOR THIS EVENT. A
FEW MODELS ACTUALLY SHOW KPIR CHANGING OVER TO SNOW SEVERAL HOURS
BEFORE KMBG DOES DUE TO THE PLACEMENT OF THE H5 LOW PRESSURE.
THERE WILL DEFINITELY BE A FINE LINE BETWEEN SIGNIFICANT SNOW
ACCUMULATIONS AND NO SNOWFALL. WITH THE CENTRAL AND WESTERN
PORTIONS OF CORSON AND DEWEY COUNTY SEEING A MORE PROLONGED TIME
PERIOD OF SNOW...HAVE UPGRADED THESE COUNTIES TO A WINTER STORM
WARNING. SINCE SNOW WILL BE DELAYED ELSEWHERE...WILL PUSH THE
WINTER STORM WATCH BACK UNTIL 0Z.
FURTHER EAST...MODELS HAVE DEVELOPED A NOTICEABLE DRY SLOT MOVING
ACROSS THE EASTERN CWA AFTER 6Z SATURDAY. THE CONSENSUS AMONG
MODELS WITH REGARDS TO QPF IS DRASTICALLY LOWER THAN THE PREVIOUS
FORECAST. MODEL SOUNDINGS ARE MORE SUPPORTIVE OF CONTINUOUS DRIZZLE
THAN MODERATE RAINFALL. HAVE LEFT OUT THE MENTION OF DRIZZLE FOR
NOW HOWEVER.
IT HAS BEEN NOTED FOR A WHILE NOW THAT IS STORM SYSTEM WILL BRING
VERY STRONG NORTHERLY WINDS WITH GUSTS AROUND 50 MPH POSSIBLE. THE
PREVIOUS FORECAST SHIFT HAD ALREADY ISSUED A WIND ADVISORY WHICH
LOOKS REALLY GOOD. BASED ON THE GFS LAMP GUIDANCE...HAVE DECIDED
TO ADD BROWN COUNTY INTO THE ADVISORY...AND HAVE EXTENDED THE
ADVISORY IN TIME UNTIL 12Z SATURDAY. CONDITIONS SHOULD GRADUALLY
IMPROVE DURING THE AFTERNOON HOURS ON SATURDAY FROM WEST TO EAST.
.LONG TERM...SUNDAY THROUGH FRIDAY
A QUIET PERIOD EXPECTED AFTER THE LOW CURRENTLY AFFECTING THE
PLAINS EXITS THIS CWA SUNDAY MORNING. UPPER RIDGING AND A SURFACE
BASED LEE SIDE TROUGH WILL MOVE IN FROM THE WEST ON MONDAY AND
TEMPERATURES WILL REBOUND NICELY WITH EXPECTED HIGHS IN THE 60S
THROUGH THE WEEK. WEAK SFC LOW PRESSURE WILL SPREAD OVER THE
REGION BY WED BUT WILL BE MOISTURE STARVED INITIALLY. AS ANOTHER
UPPER TROF MOVES IN THU NIGHT/FRIDAY AND A WELL STACKED LOW
DEVELOPS OVER THE PLAINS PRECIP CHANCES INCREASE.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
STRONG UPPER LEVEL LOW PRESSURE AREA WILL CONTINUE TO WRAP
RAIN/ISOLATED STORMS UP TO THE NORTHWEST AND WEST ACROSS ALL OF
THE REGION THROUGH TONIGHT AND SATURDAY MORNING. THUS...HAVE
RAIN/DRIZZLE/FOG IN FOR ALL LOCATIONS THROUGH SATURDAY MORNING ALONG
WITH SOME VICINITY THUNDER IN THIS AFTERNOON AT MBG/PIR. ABR AND
ATY MAY ALSO HAVE SOME THUNDER INTO THE EVENING HOURS. WILL WATCH
FOR THIS. WITH THE DRY SLOT WRAPPING UP INTO THE REGION
TONIGHT...MAY HAVE SOME DRIZZLE OCCUR AT ABR AND ATY.
OTHERWISE...ADDED SOME RAIN/SNOW IN OUT WEST FOR PIR AND MBG AS
TEMPERATURES FALL SOME OUT THERE. CEILINGS AND VISIBILITIES WILL
BE IFR/LOW MVFR THROUGH THE FORECAST PERIOD.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SATURDAY FOR BROWN-
BUFFALO-CAMPBELL-CORSON-DEWEY-EDMUNDS-FAULK-HAND-HUGHES-
HYDE-JONES-LYMAN-MCPHERSON-POTTER-STANLEY-SULLY-WALWORTH.
WINTER STORM WATCH FROM 7 PM CDT /6 PM MDT/ THIS EVENING THROUGH
SATURDAY AFTERNOON FOR CAMPBELL-HUGHES-JONES-POTTER-STANLEY-
SULLY-WALWORTH.
WINTER STORM WARNING UNTIL NOON MDT SATURDAY FOR CORSON-DEWEY.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...WISE
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
330 PM CDT FRI OCT 4 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 330 PM CDT FRI OCT 4 2013
FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL TONIGHT AND
THE POSSIBILITY OF A FEW SEVERE STORMS IN CENTRAL WISCONSIN LATE
SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON.
LATEST SURFACE OBSERVATIONS SHOWED SURFACE LOW PRESSURE OVER
CENTRAL NEBRASKA...LIFTING NORTHEAST. A WARM FRONT EXTENDED
SOUTHEAST THROUGH SOUTHWEST AND CENTRAL IOWA. THE FRONT WILL LIFT
NORTH LATE THIS AFTERNOON INTO THIS EVENING AND BE THE FOCUS FOR
STRONG TO SEVERE THUNDERSTORM DEVELOPMENT AS A POTENT UPPER LOW
PUSHES EAST ACROSS THE NEBRASKA PANHANDLE.
THE WARM FRONT IS EXPECTED TO LIFT NORTH INTO NORTHERN IOWA AND
PERHAPS EXTREME SOUTHWEST WISCONSIN THIS EVENING. STRONG 850 MB
MOISTURE TRANSPORT FOCUSES INTO THE FRONT THIS EVENING...LEADING TO
SHOWERS AND THUNDERSTORMS DEVELOPING OVER NORTHEAST IOWA...SOUTHEAST
MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. MEANWHILE THE SURFACE
LOW WILL LIFT NORTH INTO SOUTHEAST SOUTH DAKOTA AS THE LOW OCCLUDES.
A TRIPLE POINT LIFTS NORTHEAST FROM NORTHEAST IOWA INTO SOUTH
CENTRAL MINNESOTA LATE IN THE EVENING. THE 04.17 HRRR SHOWS ISOLATED
STRONG STORMS DEVELOPING ALONG THE FRONT. STORMS ALSO DEVELOP OVER
WESTERN IOWA EARLY THIS EVENING CLOSER TO THE OCCLUSION. THESE STORMS
WILL LIKELY BE SUPERCELLS...CAPABLE OF PRODUCING LARGE
HAIL...DAMAGING WINDS AND ISOLATED TORNADOES. THE STORMS FURTHER TO
THE NORTH OVER THE FORECAST AREA...SHOULD BE NORTH OF THE WARM
FRONT AND ELEVATED IN NATURE. 1-7 KM BULK SHEAR VALUES HOVER RIGHT
AROUND 30 KTS DURING THE EVENING HOURS SO CANNOT RULE OUT ISOLATED
SEVERE STORMS CAPABLE OF PRODUCING LARGE HAIL...HEAVY
RAINFALL...AND POSSIBLY DAMAGING WINDS. THE HIGHEST CHANCES FOR
SEVERE WEATHER WILL BE OVER NORTHEAST IOWA AND SOUTHEAST
MINNESOTA...WEST OF HIGHWAY 52. A FEW OF THESE STRONGER STORMS
COULD MAINTAIN INTENSITY INTO PORTIONS OF WESTERN WISCONSIN BUT
SHOULD THEN WEAKEN AS THEY MOVE EAST...BUT STILL CAPABLE OF
PRODUCING HEAVY RAINFALL. THE 850 MB MOISTURE TRANSPORT GRADUALLY
SHIFTS EAST INTO WESTERN WISCONSIN OVERNIGHT WITH WIDESPREAD
SHOWERS AND STORMS PERSISTING. THE MAIN THREAT FROM THE STORMS
SHOULD GRADUALLY SHIFT TOWARDS HEAVY RAIN LATE IN THE NIGHT. A
COLD FRONT THEN PUSHES EAST ACROSS THE REGION EARLY SATURDAY
MORNING AND SHOULD BE POSITIONED RIGHT ALONG THE MISSISSIPPI RIVER
BY THE MID TO LATE MORNING HOURS. IF ENOUGH INSTABILITY CAN BUILD
AHEAD OF THE FRONT...THERE IS THE POSSIBILITY OF SEEING A FEW
STRONG TO SEVERE STORMS OVER CENTRAL WISCONSIN. THE MAIN HAZARDS
FROM THESE STORMS WOULD BE DAMAGING WINDS. SHOWERS AND STORMS WILL
END FROM WEST TO EAST SATURDAY AFTERNOON AS A DRY SLOT PUSHES INTO
THE REGION. TEMPERATURES SHOULD FALL ACROSS THE AREA SATURDAY
AFTERNOON IN THE WAKE OF THE COLD FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 PM CDT FRI OCT 4 2013
MOST OF THE FORECAST AREA WILL REMAIN IN THE DRY SLOT SATURDAY
NIGHT...WITH THE EXCEPTION OF NORTH CENTRAL WISCONSIN WHERE A FEW
SHOWERS MAY LINGER. PLAN ON A COOLER NIGHT WITH LOWS FALLING INTO
THE 40S. A FEW 30S CANNOT BE RULED OUT OVER CENTRAL WISCONSIN. THE
UPPER LOW MOVES INTO INTO WESTERN IOWA ON SUNDAY AND EVENTUALLY
INTO WESTERN ILLINOIS SUNDAY NIGHT. SHOWERS WRAPPING AROUND THE
LOW LOOK TO MOVE INTO THE REGION SUNDAY AND WILL LIKELY CONTINUE
INTO SUNDAY NIGHT AS THE LOW PROGRESSES EAST. THE LOW THEN LOOKS
TO MOVE INTO THE EASTERN GREAT LAKES LATE ON TUESDAY WITH HIGH
PRESSURE BUILDING INTO THE AREA IN ITS WAKE. HIGH PRESSURE THEN
BUILDS OVER THE AREA WEDNESDAY INTO THURSDAY WITH DRY AND QUIET
WEATHER EXPECTED...OUTSIDE OF THE POSSIBILITY OF OF SOME EARLY
MORNING VALLEY FOG. A TROUGH IS EXPECTED TO DIG INTO THE SOUTHWEST
CONUS LATE IN THE WEEK. SOUTHWEST FLOW LOOKS TO DEVELOP OVER THE
UPPER MISSISSIPPI RIVER VALLEY LATE FRIDAY INTO SATURDAY. FORECAST
MODELS SHOWS THE TROUGH EJECTING INTO THE CENTRAL AND NORTHERN
PLAINS...WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS SYSTEM OVER
THE NEXT SEVERAL MODEL RUNS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1217 PM CDT FRI OCT 4 2013
BULK OF AREA SOCKED UNDER IFR TO LIFR CONDITIONS NORTH OF A BOUNDARY
THAT LIES CLOSER TO HIGHWAY 20 IN IOWA. THESE CONDITIONS ARE NOT
EXPECTED TO CHANGE MUCH IN THE SHORT TERM BUT AS DYNAMICS TAKE OVER
WITH SIGNIFICANT UPPER LOW PROGRESSING INTO CENTRAL STATES...
WIDESPREAD LIFT AND ASSOCIATED CONVECTION SHOULD REFORM TO THE
SOUTHWEST AND SWEEP IN. HIGHEST RISK FOR CONVECTION IS IN EVENING
HOURS AND INTO THE OVERNIGHT...WHERE VISIBILITIES COULD ACTUALLY
IMPROVE A BIT UNDER THE RAIN. CEILINGS THOUGH WILL REMAIN LOW SIDE
FOR POOR AVIATION WEATHER OVERALL.
MAIN COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL BE SWEEPING THROUGH
ON SATURDAY. BESIDES WIND SHIFT...EXPECT RAPIDLY IMPROVING
CONDITIONS AS COOLER AND DRIER AIR SWEEPS IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....SHEA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1217 PM CDT FRI OCT 4 2013
.UPDATE...(SEVERE WEATHER RISK TODAY/TONIGHT)
ISSUED AT 1027 AM CDT FRI OCT 4 2013
SETUP FOR LATER TODAY EVEN MORE MUDDLED WITH MAIN WARM FRONT SO FAR
SOUTH AT MOMENT. TRENDS IN MESOSCALE GUIDANCE AND OBSERVATIONS
SUGGEST...AS PREVIOUS FORECASTERS POINTED OUT...THAT HIGH RISK OF
SEVERE WEATHER APPEARS TO BE SHIFTING WEST AND SOUTH. STORM
PREDICTION CENTER GUIDANCE ALSO TRENDING THAT WAY AND WILL BE
INTERESTING TO SEE WHAT LATER UPDATES PROGRESS TO.
ALONG AND NORTH OF INTERSTATE 90...COOL FLOW NORTH OF BOUNDARY SEEMS
TO BE WELL ESTABLISHED AND REINFORCING LOW CLOUDS AND FOG. FLOW MORE
DISCRETE ACROSS IOWA INTO SOUTHERN WISCONSIN BEHIND EXITING
MESOSCALE CONVECTIVE SYSTEM...WITH MAIN OUTFLOW NEARLY TO THE
MISSOURI BORDER AT MOMENT. YOU HAVE TO GO TO SOUTHWEST IOWA TO FIND
BREAKS IN CLOUDS BUT LOTS OF CLOUD DEBRIS UPSTREAM THAT MAY DAMPEN
THREATS OF WARM SECTOR ADVANCING NORTH. DYNAMICS OF APPROACHING WAVE
WILL CERTAINLY PROVIDE PUSH NORTH BUT THIS MIGHT MATERIALIZE AS
WIDESPREAD CONVECTIVE DEVELOPMENT. WINDOW FOR STRONGER SUPERCELLS
AND RELATED HIGHER SEVERE WEATHER RISK MAY BE NARROW AND AGAIN...
FURTHER WEST OR SOUTHWEST OF AREA. WIDESPREAD SHOWER ACTIVITY WILL
LIKELY HAVE EMBEDDED...FAST MOVING ELEVATED THUNDERSTORMS FROM LATE
AFTERNOON INTO EVENING...WITH THREAT OF STRONGER TO SEVERE STORMS
MOVING IN LATER IN EVENING IN DIMINISHING STATE.
ALL IN ALL...LOTS OF UNCERTAINTIES BUT THREAT FOR ROUNDS OF HEAVY
RAIN AND LIGHTNING STILL THERE. WILL CONTINUE TO MONITOR SEVERE
WEATHER TRENDS AND IF NEEDED...TRANSITION PRODUCT SUITE TO LESS OF A
RISK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT FRI OCT 4 2013
MOST OF THE FORECAST WAS SPENT ON TRYING TO IMPROVE THE FORECAST
TODAY THROUGH SATURDAY AND EVALUATING THE SEVERE WEATHER RISK. IT
LOOKS LIKE THERE IS A RISK...BUT THE THREAT HAS DIMINISHED
SOMEWHAT AND SHIFTED WEST.
SURFACE ANALYSIS SHOWING COMPLEX YET FAIRLY ORGANIZED AIR MASS
FRONTAL BOUNDARIES THIS MORNING. STALLED SURFACE BOUNDARY
ORIENTED SW-NE ACROSS NE IA AND SWRN WI WITH SOME CAPE ALONG AND
TO ITS SOUTH. MORE OF THE MARITIME TROPICAL AIR IS LOCATED SOUTH
OF A WARM-STATIONARY FRONT IN THE VICINITY OF THE IA-MO
BORDER...FEEDING WITH MUCH OF THE NOCTURNAL CONVECTION IN IA. MAIN
SYNOPTIC SURFACE LOW ASSOCIATED WITH THE STRONG-DEEP TROPOSPHERIC
SYSTEM OVER UTAH IS STILL LOCATED BACK IN WRN KS. WEAK PRESSURE
FALLS OF 1MB/3HR CENTERED OVER NEBRASKA SUGGEST THE LOW CENTER
SHOULD EJECT WEST OF OMAHA. 04.00Z NAM HAS THE BEST LOOKING SEA-
LEVEL VERIFICATION AT 06Z.
MID-UPPER LEVEL SYSTEM CENTERED OVER UT PER WATER VAPOR
IMAGERY...WITH SIGNIFICANT POTENTIAL VORTICITY IN THE SRN MOST PART
OF THE STATE WITH A TROP FOLD DOWN TO ABOUT 500MB. HAVE SOME
CONCERNS WITH UPPER JET ENERGY ON NORTHWEST SIDE OF TROUGH WITH
SPOKANE RAOB COMING IN WITH 130 KTS...WHICH 04.00Z GFS INITIALIZED
BEST BUT STILL TOO WEAK...AND 110 KTS IN SRN B.C. NET EFFECT OF
UNDER INITIALIZATION /10-15KTS/ WOULD BE TO HOLD THE MID-UPPER
TROUGH ENERGY BACK IN THE SW U.S. AND EJECT THE SRN UT ENERGY
SLIGHTLY FURTHER WEST THAN CURRENTLY FORECAST. WATER VAPOR ALSO
YIELDING A FOOTPRINT OF A SHORTWAVE TROUGH SW OF OMAHA AT 05Z
ENHANCING CONVECTION SHIFTING NORTHEAST. THIS WILL MOVE THROUGH
THE FORECAST AREA.
FOR THE MOST PART THE LATEST MODEL GUIDANCE PROVIDES SOME CONSENSUS
ON THE NEXT DAYS. BUT THE DETAILS ON TIMING ARE STILL GOING TO BE
DIFFICULT. LOOKING AT THE TRENDS IN THE MODELS...THE 12 HOUR TREND
/12-18-00Z MODEL RUNS/ AT THE SURFACE IS FOR A SLOWER AND FURTHER
SOUTHWEST POSITION TO THE SYNOPTIC FEATURES. THIS FAVORS A SURFACE
LOW IN NERN NEB BY EARLY THIS EVENING...WITH THE SLOWLY NORTHWARD
MOVING WARM FRONT JUST TO OUR SOUTH IN IA /VERSUS I-90/ AND THE
FORECAST AREA IN SE-EASTERLY FLOW...COOLER THERMAL CONDITIONS ALL DAY
FRIDAY NORTH OF THE WARM FRONT. WITH MUCH OF THE CAPE TIED TO THE
WARM SECTOR...AND THE SLOWER TIMING INTO THE OVERNIGHT FOR THE
WARM SECTOR ARRIVAL...THIS SHOULD DECREASE THE SEVERE WEATHER
POTENTIAL ACROSS THE AREA...AT LEAST FOR TORNADOES AND LARGE HAIL
AND DAMAGING WIND COVERAGE. IT APPEARS THE HIGHEST RISK IS FURTHER
WEST/SOUTH THAN YESTERDAYS FORECAST.
THIS MORNINGS SHORTWAVE TROUGH EAST OF KDSM AT 08Z LOOKS TO
CONTINUE NORTHEAST THIS MORNING BRINGING RAIN NORTHWARD. MUCAPE
ANALYSIS INDICATES ABOUT 500 J/KG FROM NE IA TO CENTRAL WI AND
SOUTHEAST. PER THE LATEST WIND PROFILES...THE LOW-LEVEL JET IS
CONVERGENT INTO SRN IA AND PER THE LATEST RAP FORECASTS...THAT THE
STRONGER FORCING REMAINS /SRN IA/ UNTIL LATER WHEN IT STARTS TO
SHIFT NORTH. HOWEVER...THE 04.07Z RAP NOW SUGGESTS A SLIGHT
MOISTURE TRANSPORT SIGNAL MOVES NORTH WITH THE SHORTWAVE INTO
CENTRAL WI. WEAK...BUT MAYBE ENOUGH TO KEEP SOME SHOWERS GOING
INTO CENTRAL WI. HAVE DETAILED THE PRECIPITATION CHANCES FOR TODAY
TO HAVE MINIMUM AROUND MID DAY AFTER MORNING RAINS...ESPECIALLY
IN THE SOUTH.
TODAY WITH BOUNDARY ACROSS THE FORECAST AREA AND THE SOUTHERN WARM
FRONT MERGING TODAY...THERE IS PLENTY OF SOUTHEAST FLOW ACROSS THE
SOUTH MAKING FOR LARGER CURVING HODOGRAPHS BY LATER AFTERNOON.
HOWEVER...THE LOW-LEVEL WIND FIELD IS NOT CONVERGENT EXCEPT ON THE
FRONT FURTHER SOUTH OF THE FORECAST AREA. THE AIR MASS SEEMS TO
HAVE LITTLE CAP INDICATED IN THE FORECAST MODELS IN THE SOUTH
AROUND MID-DAY. THUS...AS THE SYSTEM EJECTS FROM THE ROCKIES AND THE
SOUTHERLY JET INCREASES...WIDESPREAD SHOWERS AND STORMS SHOULD
DEVELOP IN ISENTROPIC LIFT AND A CONVERGENT LOW-LEVEL JET ACROSS
NRN IA BY MID-LATE AFTERNOON. THIS BROAD LIFT AND LACK OF SURFACE
CONVERGENCE IN THE FORECAST AREA SEEMS TO SUGGEST A BROAD AREA OF
COMPETING STORMS WOULD USE THE AVAILABLE CAPE....NOT A SURFACE-
BOUNDARY-FORCED CAP BREAKING EVENT WHICH WOULD FAVOR TORNADOES AND
MORE SEVERE WEATHER. THUS...IT SEEMS EMBEDDED SEVERE STORMS WITH
IN A BROADER HEAVY RAIN PRECIPITATION REGION SHOULD DEVELOP ACROSS
THE SOUTH LATER THIS AFTERNOON. THE FORCING IS BEST WEST OF THE
MISSISSIPPI RIVER.
THE SPC MODERATE RISK HAS NOT EVOLVED WEST...EVEN THOUGH THE
WEATHER SYSTEM SOLUTION HAS...TO FURTHER WEST AND SLOWER. WOULD
THINK THE MODERATE RISK IS WEST OF THE FORECAST AREA. THE BEST
THREAT FOR THE SEVERE STORMS LOOKS TO BE SOUTHWEST OF A DODGE
CENTER MN TO BOSCOBEL WISCONSIN LINE...AND WILL CHANGE FORECAST
PRODUCTS ACCORDINGLY. IT SEEMS THE LACK OF A GOOD SURFACE WARM
FRONTAL BOUNDARY AND CONVERGENCE WILL FAVOR A BROAD CONVECTIVE
MODE RATHER THAN SUPERCELLS...AND THUS A VERY REDUCED TORNADO
THREAT.
TONIGHT MAY PROVIDE A BETTER SEVERE THREAT AS THE COLD FRONT
INITIATED CONVECTIVE LINE FROM WESTERN IA SHIFTS EAST AND ARRIVES
IN THE LATE EVENING. FORCING AND DYNAMICS ARE STRONGER...BUT CAPE
IS REALLY LOWERING IN THAT 03-06Z PERIOD...HOWEVER THE FORECAST
AREA...ESPECIALLY I-90 AND SOUTH...SEEMS TO GET INTO A NARROW WARM
SECTOR REGION. SO...BOWING WIND SEGMENTS OF CONVECTION ARE
WITH WIND DAMAGE POSSIBLE. THIS IS A DIFFICULT FORECAST AS SOME
STORMS/RAIN ARE EXPECTED ASSOCIATED WITH THE WARM FRONT FORCING IN
THE HOURS PRIOR. THUS LATE EVENING AND OVERNIGHT CONVECTION MAY
BE ALL DYNAMICS AND LITTLE CAPE. NORTH OF THE TRIPLE POINT...SERN
MN INTO CENTRAL WI...HEAVY RAIN IN STRONGLY FORCED ISENTROPIC LIFT
SEEMS TO BE A STRONG SIGNAL IN THE MODELS. THERE COULD BE
LOCALIZED FLOODING THREATS THERE...DEPENDING ON RATES. THE SOILS
SHOULD BE ABLE TO HANDLE A FEW INCHES IF IT DOESNT COME AT ONCE.
WILL REISSUE AN ESF/DISCUSSION ON THIS RAIN POTENTIAL.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 AM CDT FRI OCT 4 2013
THE COLD FRONT IS MOVING THROUGH THE FORECAST AREA OVERNIGHT AND
SATURDAY IT WILL BE FOUND IN CENTRAL WI AROUND MID-DAY. STORMS MAY
INITIATE ON THE FRONT...BUT IT WOULD APPEAR THE BETTER SEVERE
RISK WOULD BE EAST OF THE FORECAST AREA. SHOULD THE FRONT
SLOW...INSTABILITY WOULD IN THE LOWER CATEGORY IN HIGH
SHEAR...CAPABLE OF MINI-SUPERCELLS AND HAIL-WIND THREATS.
SUNDAY CONTINUES TO BE COOL IN THE POST-FRONTAL ENVIRONMENT. THERE
STILL APPEARS TO BE SOME TIMING AND INTENSITY DIFFERENCES WITH THE
DEFORMATION BAND OF PRECIPITATION BEHIND THE DEPARTING LOW. HAVE
DECIDED TO INCREASE PRECIPITATION CHANCES SUNDAY ESPECIALLY FURTHER
NORTHWEST.
MONDAY THROUGH THURSDAY...ANOTHER PERIOD OF ABOVE NORMAL FALL DAYS
WITH A GOOD AMOUNT OF SUNSHINE AS LONG WAVE RIDGING AGAIN BUILDS
IN. MODEL AGREEMENT AND CONFIDENCE IS HIGH FOR THIS PERIOD AS THE
LONG WAVE TROUGH DIGS OVER THE SOUTHWEST U.S. WEATHER SHOULD
BECOME MORE ACTIVE FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1217 PM CDT FRI OCT 4 2013
BULK OF AREA SOCKED UNDER IFR TO LIFR CONDITIONS NORTH OF A BOUNDARY
THAT LIES CLOSER TO HIGHWAY 20 IN IOWA. THESE CONDITIONS ARE NOT
EXPECTED TO CHANGE MUCH IN THE SHORT TERM BUT AS DYNAMICS TAKE OVER
WITH SIGNIFICANT UPPER LOW PROGRESSING INTO CENTRAL STATES...
WIDESPREAD LIFT AND ASSOCIATED CONVECTION SHOULD REFORM TO THE
SOUTHWEST AND SWEEP IN. HIGHEST RISK FOR CONVECTION IS IN EVENING
HOURS AND INTO THE OVERNIGHT...WHERE VISIBILITIES COULD ACTUALLY
IMPROVE A BIT UNDER THE RAIN. CEILINGS THOUGH WILL REMAIN LOW SIDE
FOR POOR AVIATION WEATHER OVERALL.
MAIN COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL BE SWEEPING THROUGH
ON SATURDAY. BESIDES WIND SHIFT...EXPECT RAPIDLY IMPROVING
CONDITIONS AS COOLER AND DRIER AIR SWEEPS IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE.......SHEA
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION.....SHEA