Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/14/12
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 PM MST TUE SEP 11 2012
.SYNOPSIS...AMPLE MOISTURE FOR SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. A DRIER WESTERLY FLOW WILL LEAD TO MUCH LESS
THUNDERSTORM ACTIVITY THURSDAY INTO THE WEEKEND.
&&
.DISCUSSION...KEMX WSR-88D DETECTED SCATTERED 30-50 DBZ ECHOES
MOVING NEWD ACROSS WRN SANTA CRUZ/ERN PIMA COUNTIES AT 0405Z. THE
REST OF SE AZ WAS VOID OF PRECIP ECHOES AT THIS TIME. IR SATELLITE
IMAGERY AND SURFACE OBSERVATIONS INDICATED CLEAR SKIES ACROSS FAR
WRN PIMA COUNTY. ELSEWHERE...PARTLY CLOUDY TO MOSTLY CLOUDY SKIES
PREVAILED.
SHORTWAVE TROUGH WITH AXIS EXTENDING FROM CENTRAL NEVADA TO SRN
CALIFORNIA WILL MOVE SLOWLY EWD ACROSS THE SWRN CONUS THRU WED.
12/00Z NAM AND 12/00Z RUC HRRR PROG FAIRLY ROBUST QPF/S AS WELL AS A
FAIRLY LARGE AREA OF COMP REFLECTIVITY ECHOES THE REST OF TONIGHT
ACROSS MUCH OF SE AZ. BASED ON SATELLITE/RADAR TRENDS...BELIEVE
THESE PROGGED QPF/S AS WELL AS PRECIP ECHOES ARE OVERDONE.
HOWEVER...GIVEN THE AMPLE MOISTURE AS WELL AS THE AFOREMENTIONED
SHORTWAVE TROUGH AXIS STILL TO BE WEST OF THE AREA...WILL MAINTAIN
SCATTERED SHOWERS/TSTMS FROM TUCSON EWD AND A SLIGHT CHANCE OF
SHOWERS/TSTMS WEST OF TUCSON THE REST OF TONIGHT. ISOLATED TO
SCATTERED SHOWERS/TSTMS TO OCCUR WED MORNING.
THE OFFICIAL FORECAST WAS UPDATED TO REFLECT THE ABOVE SCENARIO.
PLEASE REFER TO THE PREVIOUS DISCUSSION BELOW FOR ADDITIONAL DETAIL.
&&
.PREV DISCUSSION...MID TO UPPER LEVEL DRYING...GENERALLY ABOVE
700MB...WILL COMMENCE STARTING WEDNESDAY AFTERNOON AS A WEST TO
NORTHWESTERLY FLOW DEVELOPS DUE TO RIDGING OVER THE WESTERN US.
SURFACE BASED MOISTURE MAY LINGER FOR A FEW MORE DAYS...BUT THE
DRYING AND WARMING ALOFT SHOULD GREATLY LIMIT PRECIP CHANCES.
THE MAIN CAVEAT TO THE DRY FORECAST IS THE EVENTUAL POSITION OF OUR
EXITING UPPER TROUGH. AS THE RIDGE BUILDS ACROSS THE WESTERN US...
THIS TROUGH MAY ONCE AGAIN CUT OFF FROM THE MEAN FLOW AND PARK OVER
NEW MEXICO THROUGH FRIDAY OR POSSIBLY SATURDAY BEFORE FINALLY
KICKING EAST OVER THE WEEKEND. IF THIS PANS OUT...THE FAR EASTERN
PORTION OF AZ MAY STILL SEE RAIN CHANCES. THE ECMWF MOS GUIDANCE
ALONG WITH THE MAV AND MET ALL PAINT CHANCE POPS OR GREATER ACROSS
PORTIONS OF COCHISE...GRAHAM AND GREENLEE COUNTIES FRIDAY MORNING.
SO I INCREASED RAIN CHANCES A FEW POINTS BUT LEFT ROOM TO INCREASE
FURTHER IF MODEL TRENDS CONTINUE.
OTHERWISE...ANOTHER WARMING TREND IS EXPECTED AS THE DRIER AIR MOVES
INTO SE ARIZONA. ANTICIPATE HIGH TEMPERATURES INCREASING TO NEAR OR
SLIGHTLY ABOVE NORMAL STARTING THURSDAY AND REMAIN FAIRLY PERSISTENT
THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...SCT -TSRA/-SHRA MAINLY FROM KTUS EWD/SWD AND A SLIGHT
CHANCE OF -TSRA/-SHRA NW OF KTUS THRU WEDNESDAY EVENING OR 13/06Z.
WIND GUSTS BRIEFLY APPROACHING 35 KTS WITH THE STRONGEST TSRA
WEDNESDAY AFTERNOON. OTHERWISE...VFR CONDITIONS AND SURFACE WIND
GENERALLY LESS THAN 10 KTS THRU 13/06Z. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED THUNDERSTORMS THROUGH WEDNESDAY MAINLY
FROM TUCSON EASTWARD. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS EAST
OF TUCSON THURSDAY THROUGH THE WEEKEND. WITH DECREASING MOISTURE
THROUGH THE WEEKEND...EXPECT DAYTIME HIGH TEMPERATURES TO INCREASE
AND MINIMUM RELATIVE HUMIDITY VALUES TO DECREASE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
335 PM EDT Wed Sep 12 2012
.NEAR TERM [Tonight]...
Isolated to scattered showers were maintained in the forecast, and
should affect mainly the Gulf of Mexico waters, as well as immediate
coastal locations and the eastern Florida Big Bend. Convection thus
far near the Suwannee River has been quite shallow with no lightning
noted. The HRRR continues this trend overnight, but some thunder was
included for offshore areas of the coastal waters. We should see a
mix of mid-high level cloud cover again tonight which should keep
low temperatures in the mid-60s in most non-coastal areas, and close
to 70 around the coast.
&&
.SHORT TERM [Thursday Through Friday]...
The mid level ridge over the Eastern CONUS will continue to break
down through the remainder of the week as a trough builds toward the
Mid Atlantic by Friday. Our region will remain in a steady easterly
flow regime with gradually increasing moisture levels each day. The
absence of any large scale support (the main energy with the trough
will stay well to the north), rain chances will be on the low side.
Confidence in this forecast is bolstered by the NAM coming more
inline with the GFS with respect to its pop forecast favoring lower
end chances through the end of the week.
&&
.LONG TERM [Friday Night through Tuesday]...
The large scale longwave pattern commences in Nrn stream with a weak
trough along West Coast, broad ridge Ewd to Appalachians and low
over QUE with trough axis SWD along Atlc Coast. SRN stream marked by
high over Srn CA/Baja, trough over Srn Plains and weak ridging Ewd
to FL as high again anchors to our N. At surface, low over Great
Lakes with cold front SWD thru Ern TN Valley then SW thru SE TX.
This places local area in weak warm sector with onshore flow and
weakening gradients ending ELY surges.
The latest run of the 00z GFS and EURO coming into better agreement
showing an increasingly amplifying/digging trough moving from Plains
Ewd to dominate Gulf region by Mon. Deepening trough drags cold
front SEWD to bisect our area by Mon eve. At same time, a shortwave
over the Plains to commence the period gets swept into longwave
trough and moves NEWD enhancing local rainfall by Sat. Also it
likely develops surface reflection in W/Cntrl Gulf Coast by Sat
night that lifts along front across local area late Sun into Mon
then out of our area by late Tues. This solution would favor a
relatively wet and windy period especially Sun eve thru Tues.
Will go with wdly sct-lo sct POPs Fri night, Sct pops Sat thru Tues
with highest pops on Mon. With area being in warm sector and under
ample clouds, min temps with with several degrees above climo. Max
temps will hover around climo. Avg inland climo is 66/87 degrees.
&&
.AVIATION [Through 18z Thursday]...
VFR expected through the TAF period. A few very brief or isolated
-SHRA possible at VLD through late afternoon, so VCSH was added to
the TAF. One couldn`t be ruled out at TLH, but confidence is lower
there, so none were mentioned in the 18z set of TAFs.
&&
.MARINE...
Our coastal waters will reside on the southern edge of the
high pressure for the next several days. The increased
pressure difference between the edge of the ridge, and the weaker
pressure pattern in the Gulf will create elevated winds through at
least Thursday. Additionally, the easterly wind will yield
nocturnal surges that spread from east to west each night through
the remainder of the week.
&&
.FIRE WEATHER...
The trend in low-level moisture should be for a gradual increase
through the weekend and early next week. Red flag conditions are not
expected.
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...Small Craft Advisory from 8 PM this evening to 11 AM EDT
Thursday from Apalachicola to Suwannee River out to 60 nautical
miles.
Small Craft Advisory from 2 AM to 2 PM EDT Thursday from
Apalachicola to Destin out to 60 nautical miles.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Godsey
LONG TERM...Block
AVIATION...Lamers
MARINE...Harrigan/Godsey
FIRE WEATHER...Lamers
AREA FORECAST DISCUSSION
NWS MIAMI FL
156 PM EDT WED SEP 12 2012
.AVIATION...
AS THE EARLY AFTERNOON PROGRESSES IT LOOKS LIKE CONVECTION MAY NOT
BECOME ORGANIZED ALONG THE EASTERN ATLANTIC COASTAL ZONE WITH EAST COAST
TAF SITES KFXE...KFLL AND KMIA ASSIGNED VCSH AT 18Z AND THE MORE
INLAND SITES KTMB AND KOPF ASSIGNED VCTS IF CONVECTION BECOMES
ORGANIZED INLAND BUT CONFIDENCE IS LOW. THE TERMINAL MOST LIKELY
TO EXPERIENCE CONVECTION WILL BE TERMINAL KAPF WITH VCTS ASSIGNED
AT 19Z...WITH THE MODERATE EASTERLY FLOW THE WESTERN PORTIONS OF
THE PENINSULA WILL BE THE AREA MOST FAVORED FOR AFTERNOON
CONVECTION. WITH OCCURRENCE OF SHOWERS OR A THUNDERSTORMS BRIEF
PERIODS OF SUB-VFR CONDITIONS MAY BE EXPERIENCED.
60
&&
.PREV DISCUSSION... /ISSUED 1013 AM EDT WED SEP 12 2012/
UPDATE...
THE 12Z SOUNDING THIS MORNING SHOWED DRIER AND WARMER AIR IN THE
LOW TO MID LEVELS...WITH MODERATE EAST TO NORTHEAST FLOW UP TO
700MB. THERE WAS A WEAK BOUNDARY LOCATED ACROSS THE FLORIDA
STRAITS...AND THE HIGHER MOISTURE AND CONVERGENCE WILL BE LOCATED
SOUTH OF THE REGION TODAY. THE HRRR SHOWS THIS AS WELL...WITH
MOSTLY ISOLATED TO SCATTERED SHOWERS AS THERE WILL BE A LACK OF
FOCUS FOR STORMS. A NORTHEAST FLOW USUALLY DOES NOT FAVOR MUCH
ACTIVITY ALONG MOST OF THE EAST COAST ANYWAY...BUT WILL LEAVE THE
HIGHER POPS FOR THE SOUTHEAST COAST AS THAT REGION IS CLOSER TO
THE BOUNDARY. LOWERED POPS ACROSS THE WEST BACK TO SCATTERED AND
REDUCED TO ISOLATED THUNDERSTORMS ACROSS THE WEST AS WELL...AS THE
FLOW SHOULD BE TOO STRONG TO GET A GULF COAST SEA BREEZE.
OTHERWISE...BREEZY CONDITIONS WITH PARTLY CLOUDY TO MOSTLY CLOUDY
SKIES SHOULD PREVAIL ACROSS THE REGION...WITH HIGHS IN THE UPPER
80S TO LOWER 90S.
PREV DISCUSSION... /ISSUED 726 AM EDT WED SEP 12 2012/
AVIATION...
A STALLED FRONT OVER EXTREME S FLA/THE UPPER FLA STRAITS
WILL DISSIPATE TODAY. A STRONG RIDGE OF HIGH PRESSURE OFF OF THE NEW
ENGLAND COAST OVER THE ATLC AND EXTENDING SW INTO THE SE U.S. WILL
PERSIST THROUGH THE PERIOD. A FEW FAST MOVING SHRA MOVING OVER THE
ATLC WILL MOVE ONSHORE BUT AT THIS TIME NO VCSH IN E COAST TAFS. AFT
16Z VCTS E COAST TERMINALS BUT POSSIBLE THAT THE TSRA WILL BE W OF
TERMINALS. SURFACE WINDS CURRENTLY NE-ENE UP TO 10 KNOTS WITH GUSTS
TO MID/UPPER TEENS POSSIBLE. AFT 14Z WINDS INCREASE TO 12 TO 15
KNOTS WITH GUSTS > 20 KNOTS. AT KAPF...VFR THROUGH 16Z WITH NO
WEATHER THEN VCSH POSSIBLE UNTIL 18Z THEN VCTS. TSTMS MAY PRODUCE
FREQUENT MVFR CIG/VSBY. SURFACE WIND CURRENTLY NE < 10 KNOTS
BECOMING NE-ENE 10 TO 12 KNOTS WITH GUSTS AROUND 20 KNOTS AFT 15Z.
60
PREV DISCUSSION... /ISSUED 307 AM EDT WED SEP 12 2012/
SHORT TERM (TODAY-FRIDAY)...
A STALLED FRONTAL BOUNDARY COMBINED WITH PLENTY OF DEEP LAYER
MOISTURE WILL KEEP THE RAIN CHANCES IN THE FORECAST THROUGH THE
MID-WEEK PERIOD. EARLIER THIS MORNING...SCATTERED MODERATE TO
HEAVY SHOWERS DUE TO AN EASTERLY WIND SURGE NORTH OF THE FRONTAL
BOUNDARY IMPACTED PORTIONS OF THE LOCAL AREA...ESPECIALLY ALONG
THE EAST COAST FROM DELRAY BEACH TO LAKE WORTH WHERE ACCUMULATIONS
REACHED THE THREE QUARTER TO ONE INCH MARK WITHIN A ONE TO THREE
HOUR PERIOD. THE LATEST MODEL GUIDANCE REMAINS IN DECENT AGREEMENT
THROUGH THE UPCOMING 72 HOURS AND CONTINUES TO INDICATE THE
POTENTIAL FOR SCATTERED SHOWERS WITHIN THE MOIST EASTERLY FLOW TO
CONTINUE. MODEL PRECIPITABLE WATER VALUES ARE FORECAST TO REMAIN
AROUND THE 2 INCH MARK THROUGH THURSDAY...THEN STEADILY DECREASE
FROM NORTH TO SOUTH THURSDAY NIGHT THROUGH FRIDAY AS THE FRONTAL
BOUNDARY GRADUALLY SHIFTS SOUTH OF THE AREA AND FURTHER WEAKENS OR
DIMINISHES. AS A RESULT...WILL REFLECT THIS DECREASING RAINFALL
TREND THROUGH THE LATTER HALF OF THE SHORT-TERM PERIOD. FOR
TODAY...ALTHOUGH THE MODERATE EASTERLY FLOW WILL HELP SPREAD THE
AFTERNOON SHOWERS/TSTMS INLAND AND TOWARD THE SOUTHWEST FLORIDA
COAST...ANY ACTIVITY THAT BECOMES CONCENTRATED OVER PORTIONS OF
THE EAST COAST AND METRO AREAS ON TOP OF YESTERDAY`S RAINFALL
COULD LEAD TO MINOR FLOODING CONCERNS ONCE AGAIN.
LONG TERM (FRIDAY NIGHT-TUESDAY)...
OVER THE WEEKEND...THE MODERATE EASTERLY FLOW CURRENTLY IN PLACE
IS FORECAST TO RELAX AS THE FRONTAL BOUNDARY PREVIOUSLY DISCUSSED
DIMINISHES SOUTH OF THE AREA. THIS WILL ALLOW CONDITIONS TO RETURN
TO NORMAL FOR THIS TIME OF YEAR WITH MAINLY AFTERNOON
SHOWERS/TSTMS SETTING UP INLAND AND WEST EACH DAY. EARLY NEXT
WEEK...THE LATEST MODEL GUIDANCE INDICATES ANOTHER FRONTAL
BOUNDARY ASSOCIATED WITH A STRONG SHORTWAVE TROUGH TRANSLATING
EASTWARD ACROSS THE REGION. ALTHOUGH THE BULK OF THE DYNAMICS AND
FORCING WILL REMAIN WELL NORTH OF OUR LOCAL AREA...MOIST SOUTHERLY
FLOW WELL AHEAD OF THIS APPROACHING BOUNDARY MAY LEAD TO ABOVE
AVERAGE RAINFALL CHANCES MONDAY THROUGH TUESDAY...ESPECIALLY OVER
THE NORTHERN HALF OF THE LOCAL AREA AROUND THE LAKE REGION.
MARINE...
MODERATE EASTERLY WINDS AND SEAS WILL PERSIST THROUGH THE
MID-WEEK PERIOD...THEN STEADILY TREND BACK TOWARD NORMAL OVER THE
WEEKEND. AS A RESULT...SMALL CRAFT OPERATORS ARE ENCOURAGED TO
EXERCISE CAUTION OUT ACROSS THE LOCAL WATERS TODAY THROUGH THURSDAY.
IN ADDITION TO THE ABOVE AVERAGE WINDS AND SEAS...SCATTERED SHOWERS
AND STORMS CAN LEAD TO LOCALLY HIGHER WINDS AND SEAS ALONG WITH
REDUCED VISIBILITIES.
FIRE WEATHER...
A STALLED FRONT OVER EXTREME SOUTH FLORIDA AND THE UPPER FLORIDA
STRAITS WILL DISSIPATE TODAY. A STRONG RIDGE OF HIGH PRESSURE
EXTENDING FROM THE ATLANTIC OFF OF THE NEW ENGLAND COAST
SOUTHWEST TO OVER THE SOUTHEAST U.S....WILL PERSIST TODAY THROUGH
THURSDAY. THIS WILL PROVIDE A BRISK NORTHEASTERLY WIND FLOW OVER
SOUTH FLORIDA TODAY THROUGH THURSDAY.
SOME SHOWERS CAN BE EXPECTED THIS MORNING ALONG THE EAST COAST AND
AGAIN OVERNIGHT TONIGHT. BUT BY LATE MORNING TODAY AND AGAIN ON
THURSDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED MAINLY IN THE INTERIOR AND WEST ZONES.
DISPERSION WILL BE GENERALLY GOOD MOST ZONES TODAY AND THURSDAY WITH
VERY GOOD DISPERSION TODAY WEST OF LAKE OKEECHOBEE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 87 77 89 / 30 40 40 40
FORT LAUDERDALE 78 87 78 87 / 30 40 40 40
MIAMI 76 88 78 85 / 40 40 40 40
NAPLES 74 89 75 90 / 20 40 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
1013 AM EDT WED SEP 12 2012
.UPDATE...
THE 12Z SOUNDING THIS MORNING SHOWED DRIER AND WARMER AIR IN THE
LOW TO MID LEVELS...WITH MODERATE EAST TO NORTHEAST FLOW UP TO
700MB. THERE WAS A WEAK BOUNDARY LOCATED ACROSS THE FLORIDA
STRAITS...AND THE HIGHER MOISTURE AND CONVERGENCE WILL BE LOCATED
SOUTH OF THE REGION TODAY. THE HRRR SHOWS THIS AS WELL...WITH
MOSTLY ISOLATED TO SCATTERED SHOWERS AS THERE WILL BE A LACK OF
FOCUS FOR STORMS. A NORTHEAST FLOW USUALLY DOES NOT FAVOR MUCH
ACTIVITY ALONG MOST OF THE EAST COAST ANYWAY...BUT WILL LEAVE THE
HIGHER POPS FOR THE SOUTHEAST COAST AS THAT REGION IS CLOSER TO
THE BOUNDARY. LOWERED POPS ACROSS THE WEST BACK TO SCATTERED AND
REDUCED TO ISOLATED THUNDERSTORMS ACROSS THE WEST AS WELL...AS THE
FLOW SHOULD BE TOO STRONG TO GET A GULF COAST SEA BREEZE.
OTHERWISE...BREEZY CONDITIONS WITH PARTLY CLOUDY TO MOSTLY CLOUDY
SKIES SHOULD PREVAIL ACROSS THE REGION...WITH HIGHS IN THE UPPER
80S TO LOWER 90S.
&&
.PREV DISCUSSION... /ISSUED 726 AM EDT WED SEP 12 2012/
AVIATION...
A STALLED FRONT OVER EXTREME S FLA/THE UPPER FLA STRAITS
WILL DISSIPATE TODAY. A STRONG RIDGE OF HIGH PRESSURE OFF OF THE NEW
ENGLAND COAST OVER THE ATLC AND EXTENDING SW INTO THE SE U.S. WILL
PERSIST THROUGH THE PERIOD. A FEW FAST MOVING SHRA MOVING OVER THE
ATLC WILL MOVE ONSHORE BUT AT THIS TIME NO VCSH IN E COAST TAFS. AFT
16Z VCTS E COAST TERMINALS BUT POSSIBLE THAT THE TSRA WILL BE W OF
TERMINALS. SURFACE WINDS CURRENTLY NE-ENE UP TO 10 KNOTS WITH GUSTS
TO MID/UPPER TEENS POSSIBLE. AFT 14Z WINDS INCREASE TO 12 TO 15
KNOTS WITH GUSTS > 20 KNOTS. AT KAPF...VFR THROUGH 16Z WITH NO
WEATHER THEN VCSH POSSIBLE UNTIL 18Z THEN VCTS. TSTMS MAY PRODUCE
FREQUENT MVFR CIG/VSBY. SURFACE WIND CURRENTLY NE < 10 KNOTS
BECOMING NE-ENE 10 TO 12 KNOTS WITH GUSTS AROUND 20 KNOTS AFT 15Z.
60
PREV DISCUSSION... /ISSUED 307 AM EDT WED SEP 12 2012/
SHORT TERM (TODAY-FRIDAY)...
A STALLED FRONTAL BOUNDARY COMBINED WITH PLENTY OF DEEP LAYER
MOISTURE WILL KEEP THE RAIN CHANCES IN THE FORECAST THROUGH THE
MID-WEEK PERIOD. EARLIER THIS MORNING...SCATTERED MODERATE TO
HEAVY SHOWERS DUE TO AN EASTERLY WIND SURGE NORTH OF THE FRONTAL
BOUNDARY IMPACTED PORTIONS OF THE LOCAL AREA...ESPECIALLY ALONG
THE EAST COAST FROM DELRAY BEACH TO LAKE WORTH WHERE ACCUMULATIONS
REACHED THE THREE QUARTER TO ONE INCH MARK WITHIN A ONE TO THREE
HOUR PERIOD. THE LATEST MODEL GUIDANCE REMAINS IN DECENT AGREEMENT
THROUGH THE UPCOMING 72 HOURS AND CONTINUES TO INDICATE THE
POTENTIAL FOR SCATTERED SHOWERS WITHIN THE MOIST EASTERLY FLOW TO
CONTINUE. MODEL PRECIPITABLE WATER VALUES ARE FORECAST TO REMAIN
AROUND THE 2 INCH MARK THROUGH THURSDAY...THEN STEADILY DECREASE
FROM NORTH TO SOUTH THURSDAY NIGHT THROUGH FRIDAY AS THE FRONTAL
BOUNDARY GRADUALLY SHIFTS SOUTH OF THE AREA AND FURTHER WEAKENS OR
DIMINISHES. AS A RESULT...WILL REFLECT THIS DECREASING RAINFALL
TREND THROUGH THE LATTER HALF OF THE SHORT-TERM PERIOD. FOR
TODAY...ALTHOUGH THE MODERATE EASTERLY FLOW WILL HELP SPREAD THE
AFTERNOON SHOWERS/TSTMS INLAND AND TOWARD THE SOUTHWEST FLORIDA
COAST...ANY ACTIVITY THAT BECOMES CONCENTRATED OVER PORTIONS OF
THE EAST COAST AND METRO AREAS ON TOP OF YESTERDAY`S RAINFALL
COULD LEAD TO MINOR FLOODING CONCERNS ONCE AGAIN.
LONG TERM (FRIDAY NIGHT-TUESDAY)...
OVER THE WEEKEND...THE MODERATE EASTERLY FLOW CURRENTLY IN PLACE
IS FORECAST TO RELAX AS THE FRONTAL BOUNDARY PREVIOUSLY DISCUSSED
DIMINISHES SOUTH OF THE AREA. THIS WILL ALLOW CONDITIONS TO RETURN
TO NORMAL FOR THIS TIME OF YEAR WITH MAINLY AFTERNOON
SHOWERS/TSTMS SETTING UP INLAND AND WEST EACH DAY. EARLY NEXT
WEEK...THE LATEST MODEL GUIDANCE INDICATES ANOTHER FRONTAL
BOUNDARY ASSOCIATED WITH A STRONG SHORTWAVE TROUGH TRANSLATING
EASTWARD ACROSS THE REGION. ALTHOUGH THE BULK OF THE DYNAMICS AND
FORCING WILL REMAIN WELL NORTH OF OUR LOCAL AREA...MOIST SOUTHERLY
FLOW WELL AHEAD OF THIS APPROACHING BOUNDARY MAY LEAD TO ABOVE
AVERAGE RAINFALL CHANCES MONDAY THROUGH TUESDAY...ESPECIALLY OVER
THE NORTHERN HALF OF THE LOCAL AREA AROUND THE LAKE REGION.
MARINE...
MODERATE EASTERLY WINDS AND SEAS WILL PERSIST THROUGH THE
MID-WEEK PERIOD...THEN STEADILY TREND BACK TOWARD NORMAL OVER THE
WEEKEND. AS A RESULT...SMALL CRAFT OPERATORS ARE ENCOURAGED TO
EXERCISE CAUTION OUT ACROSS THE LOCAL WATERS TODAY THROUGH THURSDAY.
IN ADDITION TO THE ABOVE AVERAGE WINDS AND SEAS...SCATTERED SHOWERS
AND STORMS CAN LEAD TO LOCALLY HIGHER WINDS AND SEAS ALONG WITH
REDUCED VISIBILITIES.
FIRE WEATHER...
A STALLED FRONT OVER EXTREME SOUTH FLORIDA AND THE UPPER FLORIDA
STRAITS WILL DISSIPATE TODAY. A STRONG RIDGE OF HIGH PRESSURE
.EXTENDING FROM THE ATLANTIC OFF OF THE NEW ENGLAND COAST
SOUTHWEST TO OVER THE SOUTHEAST U.S....WILL PERSIST TODAY THROUGH
THURSDAY. THIS WILL PROVIDE A BRISK NORTHEASTERLY WIND FLOW OVER
SOUTH FLORIDA TODAY THROUGH THURSDAY.
SOME SHOWERS CAN BE EXPECTED THIS MORNING ALONG THE EAST COAST AND
AGAIN OVERNIGHT TONIGHT. BUT BY LATE MORNING TODAY AND AGAIN ON
THURSDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED MAINLY IN THE INTERIOR AND WEST ZONES.
DISPERSION WILL BE GENERALLY GOOD MOST ZONES TODAY AND THURSDAY WITH
VERY GOOD DISPERSION TODAY WEST OF LAKE OKEECHOBEE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 78 88 77 / 40 30 40 20
FORT LAUDERDALE 88 79 89 79 / 50 30 30 20
MIAMI 87 78 89 78 / 50 30 40 20
NAPLES 92 75 91 76 / 50 40 50 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS LINCOLN IL
859 PM CDT THU SEP 13 2012
.DISCUSSION...
ISSUED 855 PM CDT THU SEP 13 2012
UPDATED THE FORECAST TONIGHT FOR SLOWER TRENDS WITH SHOWERS MOVING
SOUTHEAST INTO CENTRAL/SOUTHEAST IL ALONG WITH SLOWER CLEARING OF
THE CLOUDS FROM NW TO SE OVERNIGHT AND FRI MORNING. BUMPED UP LOWS
A FEW DEGREES INTO THE UPPER 50S AND LOWER 60S OVER SOUTHEAST IL.
COLD FRONT WAS OVER CENTRAL INDIANA INTO SOUTHEAST IL NEAR I-70 AND
INTO SE MO TO WEAK 1018 MB LOW PRESSURE IN WEST CENTRAL AR. BAND
OF SHOWERS BEHIND THE COLD FRONT ABOUT 100 MILES WIDE WAS OVER THE
IL RIVER VALLEY AND HAS BEEN ONLY VERY SLOWLY MOVING TO THE SOUTHEAST.
THE RAIN SO FAR THIS EVENING HAS BEEN MAINLY ALONG AND NW OF THE
IL RIVER. TEMPERATURES RANGE FROM THE MID 50S NW OF THE IL RIVER
TO THE LOWER 70S AHEAD OF THE COLD FRONT SE OF I-70. SO A TASTE OF
FALL WEATHER LIES BEHIND THE COLD FRONT ACROSS CENTRAL IL RIGHT NOW.
USED THE HRRR AND RUC13 MODELS TO TIME THE BAND OF RAIN SHOWERS
PRESSING SE THROUGH CENTRAL IL TONIGHT...NOT REACHING SE IL UNTIL
LATE TONIGHT INTO FRI MORNING. HAVE CLOUDS DECREASING ACROSS THE
IL RIVER VALLEY AFTER 2 AM. CLOUDS CURRENTLY EXTEND UPSTREAM
ACROSS CENTRAL/SE IOWA. NORTH WINDS OF 5 TO 15 MPH AND A FEW GUSTS
NEAR 20 MPH EARLY TO DIMINISH UNDER 10 MPH DURING OVERNIGHT. THIS
DUE TO 1029 MB HIGH PRESSURE OVER NORTHERN KS INTO SOUTHERN IA
THAT NOSES INTO THE IL RIVER VALLEY FRI MORNING.
KH
&&
.AVIATION...
ISSUED 658 PM CDT THU SEP 13 2012
A COLD FRONT RECENTLY PASSED SE OF DEC AND CMI IN THE PAST HOUR OR
TWO MARKED BY BREEZY NORTH WINDS AROUND 15 KTS WITH GUSTS OF 20-25 KTS
AND THESE GUSTY WINDS WILL LAST ABOUT AN HOUR OR TWO. PIA NORTH WINDS
HAVE ALREADY SETTLED DOWN TO NEAR 10 KTS OR LESS. AREA OF RAIN
SHOWERS OVER THE IL RIVER VALLEY IN NW IL WILL PRESS GRADUALLY SE
TOWARD I-55 BY 02-03Z AND CMI AROUND MIDNIGHT. GENERALLY VFR
CONDITIONS EXPECTED BUT DID INCLUDE A PERIOD OF CEILINGS DOWN TO
AROUND 1K FT AT PIA AND BMI WHICH PIA ALREADY WAS AS LOW AS 700
FOOT CEILING. VSBYS GENERALLY ABOVE 5 MILES BUT COULD GET TO MVFR
3-5 MILES VSBYS AT PIA AND BMI AS PIA HAS BEEN AS LOW AS 3 MILES.
RAIN SHOULD END BETWEEN 05Z-06Z AT PIA...FROM 08Z-09Z ALONG I-55
AT BMI AND SPI AND 10-11Z AT DEC AND CMI. CLEARING OF CLOUDS TO
OCCUR A FEW HOURS AFTER THAT WITH MOSTLY SUNNY SKIES EXPECTED FRI
WITH N/NE WINDS 5-10 KTS (LIGHTEST AT PIA). CLEAR SKIES AND LIGHT
NNE WINDS BY LATE FRI AFTERNOON AS 1029 MB HIGH PRESSURE OVER THE
CENTRAL PLAINS NEAR THE KS/NE TO SETTLE INTO THE IL RIVER VALLEY BY
LATE FRI AFTERNOON BRINGING FAIR WEATHER ON FRIDAY.
KH
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT THU SEP 13 2012
THE OVERALL PATTERN FOR THE NEXT 7 DAYS WILL BE FAVORABLE FOR
COOLER THAN NORMAL TEMPS WITH PERIODIC RAINFALL CHANCES. A
LONGWAVE TROUGH WILL DOMINATE THE UPPER LEVEL FLOW ACROSS EASTERN
CANADA AND THE GREAT LAKES/NORTHEASTERN CONUS. THAT WILL SET THE
STAGE FOR A SERIES OF WAVES ARRIVING ON NORTHWEST FLOW ALOFT. THE
FIRST PERIOD OF RAIN WILL BE TONIGHT INTO FRIDAY MORNING...THE
SECOND WILL BE MONDAY AND MONDAY NIGHT...WITH THE THIRD COMING
NEXT WED NIGHT INTO THURSDAY.
SHORT TERM...TONIGHT THROUGH SUNDAY.
THE COLD FRONT ARRIVING INTO NW IL THIS AFTERNOON IS BEING SLOWED
DOWN BY A SHORTWAVE LIFTING NORTH FROM TENNESSEE AND WESTERN
KENTUCKY INTO SOUTHEAST ILLINOIS. SHOWERS ARE FEW AND FAR BETWEEN
AT THE MOMENT...BUT RAIN SHOULD FILL IN THIS EVENING AS THE
COLD FRONT GETS AN ENHANCE BOOST OF LIFT FROM THE DPVA FROM THE
SHORTWAVE IN SOUTHEAST IL. WE KEPT OUR LIKELY POPS IN FOR THIS
EVENING EVERYWHERE...THEN CONFINED THE LIKELY POPS TO SOUTHEAST OF
I-55 AFTER MIDNIGHT. THE SLOWER NATURE OF THE FRONTAL PROGRESSION
LED US TO CONTINUE WITH SOME LOW CHANCE POPS SOUTHEAST OF I-70 AND
SLIGHT CHANCES UP TO PARIS/DANVILLE FOR FRIDAY MORNING. SOME LIGHT
FOG MAY DEVELOP NORTHWEST OF THE IL RIVER LATE TONIGHT IF ANY
CLEARING REACHES THAT AREA. THE SHORT RANGE MODELS ARE INDICATING
SOME CLEARING AFTER 3 AM...SO FOG POTENTIAL WILL NEED TO BE
WATCHED.
CLEARING SHOULD PROGRESS FROM NW TO SE ON FRIDAY AS HIGH PRESSURE
BUILDS INTO THE AREA. FORECAST SOUNDINGS SHOW MIXING HEIGHTS AND LOW
LEVEL TEMPS SUPPORTIVE OF BELOW NORMAL HIGHS...WITH READINGS IN THE
LOWER 70S ACROSS THE BOARD. NORTHERLY WINDS WILL ADD SOME CHILL TO
THE AIR AS WELL.
A PLEASANT WEEKEND IS ON TAP AS HIGH PRESSURE REMAINS IN CONTROL.
WEAK RIDGING AND HEIGHT RISES ALOFT WILL AID IN SLIGHT WARMING OF
HIGH TEMPS TO NEAR NORMAL FOR SATURDAY AND SUNDAY. HIGHS SHOULD
REACH NEAR NORMAL IN THE MID TO UPPER 70S BOTH DAYS...WITH PLENTY
OF SUNSHINE.
LONG TERM...MONDAY THROUGH THURSDAY.
MONDAY WILL FEATURE THE APPROACH OF THE NEXT COLD FRONT. THE
AVERAGE TIMING OF THE FRONT IN THE EXTENDED MODELS PUTS THE
RAINFALL INTO OUR NW COUNTIES BY MID MORNING ON MONDAY...AND
CONTINUING INTO MONDAY NIGHT...ESPECIALLY SE OF I-55.
A BREAK IN THE ACTION AND COOLER TEMPS ARE EXPECTED FOR TUESDAY.
THE GFS EVEN BRINGS THE 0C LINE AT 850MB INTO NORTH CENTRAL IL
TUESDAY AFTERNOON AND EVENING. THE ECMWF AND CANADIAN KEEP THE 0C
LINE IN WISCONSIN/MICH...SO WE ARE TAKING THAT WILL A GRAIN OF
SALT. HOWEVER...THE THEME WILL BE BELOW NORMAL TEMPS FOR TUE
NIGHT/WED AND INTO THURSDAY. THE NEXT QUICK SHORTWAVE/COLD FRONT
IS EXPECTED TO MOVE SE INTO OUR COUNTIES WED NIGHT. THE EC/GFS
BOTH INDICATE THIS FEATURE PRETTY CLOSELY...SO WE KEPT THE
ALLBLEND CHANCE POPS FOR THAT TIME FRAME.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
919 PM CDT THU SEP 13 2012
.UPDATE...
PER THE LATEST NAM...RUC AND HRRR MODELS...ANTICIPATING BEST RAIN
CHANCES SLOWLY SHIFTING INTO FAR SOUTHERN/SOUTHEAST KS AS THE
NIGHT PROGRESSES...AS 700-600MB CONVERGENCE ZONE SLOWLY SHIFTS
SOUTH OVERNIGHT. THINKING BEST CHANCES AFTER MIDNIGHT WILL BE
GENERALLY SOUTH OF A LINE EXTENDING FROM KINGMAN-WICHITA-EMPORIA.
THIS AREA WILL BE CO-LOCATED UNDERNEATH BEST ZONE OF UPPER
DIFFLUENCE. AREAS OF RAIN SHOULD CONTINUE TO LINGER THROUGH FRIDAY
MORNING...WITH CHANCES REMAINING ALONG OK/KS BORDER THROUGH
FRIDAY AFTERNOON. CONSEQUENTLY...FRIDAY TEMPERATURES WILL ONCE
AGAIN BE COOLISH OVER FAR SOUTHERN KS.
ADK
&&
.PREV DISCUSSION... /ISSUED 643 PM CDT THU SEP 13 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
A RAINY AND CLOUDY 12-18 HOURS IS ANTICIPATED FOR PRIMARILY KICT
AND KCNU...WITH KHUT ON THE NORTHERN FRINGE OF THE
PRECIPITATION/CLOUDS...AS A MID-LEVEL CONVERGENCE ZONE REMAINS
NEARLY STATIONARY OVER THE REGION. THE ONLY CHANCE OF ISOLATED
THUNDER WILL BE FOR KCNU WHERE MARGINAL INSTABILITY WILL BE
PRESENT. OTHERWISE...PREVAILING VSBYS IN -RA WILL LIKELY BE
P6SM...WITH PERIODIC MVFR VSBYS IN RA. MVFR CIGS WILL PREVAIL AT
KICT-KCNU THROUGH THE PERIOD. ONLY HAVE PREVAILING VCSH AND
BKN030 AT KICT FROM 06Z ONWARD...ALTHOUGH MAY EVENTUALLY NEED TO
AMEND THIS TO INCLUDE PREVAILING -RA AND CIGS BELOW 2000 FT AGL
THROUGH AT LEAST THE PREDAWN HOURS. WILL CONTINUE TO MONITOR
TRENDS.
ADK
PREV DISCUSSION... /ISSUED 311 PM CDT THU SEP 13 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE IS THE PROGRESSION OF PRECIPITATION TODAY AND
TOMORROW AND THEN TEMPERATURES THROUGH SATURDAY.
SYNOPSIS:
THE UPPER WAVE HAS PROGRESSED EASTWARD WITH THE MAIN ENERGY LAGGING
A BIT BEHIND. PRECIPITATION CONTINUES AHEAD OF THE MAIN ENERGY
ACROSS THE EASTERN PORTIONS OF KANSAS THIS AFTERNOON. THE SURFACE
FRONT HAS CHARGED SOUTHWARD AND IS SITUATED FROM MISSOURI
SOUTHWESTWARD TO SOUTHWEST TEXAS. SCATTERED SHOWERS AND CLOUD COVER
IN ADDITION TO THE COLD AIR ADVECTION HAVE KEPT TEMPERATURES COOL
TODAY...WITH MOST LOCATIONS STAYING IN THE MID TO UPPER 50S TO LOW
60S.
TONIGHT - SUNDAY:
LIGHT SHOWERS WITH ISOLATED THUNDER WILL CONTINUE TO PROGRESS
SOUTHEASTWARD ACROSS THE AREA TONIGHT. THE UPPER ENERGY THAT IS
MOVING IN FROM NEW MEXICO WILL CONTINUE TO IMPACT THE REGION THROUGH
THE WEEKEND...CAUSING IT TO BE A LITTLE COOLER AND CLOUDIER THAN
PREVIOUSLY EXPECTED. AS THIS ENERGY TRANSLATES EASTWARD...THE LOWER
LEVELS WILL RESPOND WITH MOIST RETURN FLOW ACROSS EASTERN KANSAS.
EXPECT FRIDAY TO BE WARMER THAN TODAY...BUT STILL BELOW NORMAL WITH
HIGHS IN THE UPPER 60S TO 70S. THE WARMEST TEMPERATURES WILL BE
ACROSS CENTRAL KANSAS WHERE CLOUD COVER WILL BE MINIMAL AND
INSOLATION WILL BE GREATER. THE REAL QUESTION IS HOW FAR NORTH THE
CLOUD COVER WILL REMAIN THROUGH FRIDAY. EXPECTING THERE TO BE A
FINE LINE BETWEEN CLOUDY AND SUNNY. TEMPERATURES UNDER THE CLOUD
COVER AND POSSIBLE PRECIPITATION ARE EXPECTED TO BE IN THE 60S.
BOUNDARY LAYER MOISTURE IS EXPECTED TO CONTINUE TO SURGE NORTHWARD
ACROSS EASTERN KANSAS SATURDAY. THE CURRENT GUIDANCE
(NAM/GFS/ECMWF) INDICATES THAT MOST OF CENTRAL AND EASTERN KANSAS
WILL BE SOCKED IN UNDER LOW LEVEL CLOUDS. BECAUSE OF THIS HAVE
TRENDED COOLER FOR TEMPERATURES ON SATURDAY. FEEL THAT WIDESPREAD
TEMPERATURES IN THE 60S ARE NOT OUT OF THE QUESTION IF LOW CLOUDS
ARE PRESENT AS ADVERTISED.
CONFIDENCE ON PRECIPITATION THROUGH FRIDAY AND SATURDAY IS NOT
OVERLY HIGH...BUT FEEL THE CHANCES REMAIN FOR SCATTERED LIGHT
SHOWERS THROUGH MUCH OF THE DAY BOTH DAYS ACROSS EXTREME SOUTHERN
AND EASTERN KANSAS. EXPECTING SUNDAY TO WARM UP AND DRY OUT AS THE
UPPER ENERGY TRANSLATES MOSTLY EAST OF THE AREA.
MONDAY - THURSDAY:
THE NEXT WAVE WILL APPROACH FOR MONDAY AND WILL HELP KICK THE UPPER
ENERGY EAST THAT PLAGUED THE AREA FOR THE WEEKEND. THIS WAVE WILL
DRAG YET ANOTHER FRONT THROUGH DURING THE DAY MONDAY. THE GUIDANCE
DOES INDICATE THAT SOME PRECIPITATION WILL DEVELOP ALONG THE
FRONT...BUT CONFIDENCE ON THAT IS LOW. FEEL THE BEST CHANCES WILL
REMAIN EAST AS THE FRONT IMPACTS THE BETTER MOISTURE. TEMPERATURES
WILL AGAIN TAKE A HIT POST-FRONTAL AS SURFACE HIGH PRESSURE BUILDS IN.
A REINFORCING SHOT OF COLD AIR WILL PUSH THROUGH ON THURSDAY AS THE
NEXT PIECE OF ENERGY ROTATES AROUND THE UPPER TROUGH. THE EARLIER
FRONTS WILL HELP TO PUSH MOISTURE FROM THE AREA...AND THIS FRONTAL
PASSAGE IS LARGELY EXPECTED TO BE DRY.
BILLINGS
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
WIDESPREAD SHOWERS CONTINUE TO IMPACT MUCH OF SOUTH CENTRAL AND
CENTRAL KANSAS AND WILL SPREAD SLOWLY EAST-SOUTHEAST THROUGH THE
AFTERNOON. MVFR CIGS ARE EXPECTED TO PREVAIL FOR THE KICT/KHUT
TAF SITES FOR MOST OF THE DAYLIGHT HOURS. WILL SEE LOWER CIGS AND
LIGHT RAIN BEGIN TO IMPACT SOUTHEAST KANSAS AFTER 22Z. MVFR CIGS MAY
CONTINUE WITHIN AREAS OF LIGHT RAIN THROUGH MUCH OF THE NIGHT OVER
SOUTHEAST KANSAS WITH MORE UNCERTAINTY FURTHER WEST ACROSS SOUTH
CENTRAL KANSAS.
VFR CONDITIONS ARE EXPECTED TO RETURN TO CENTRAL KANSAS LATER THIS
AFTERNOON AS A SFC RIDGE OF HIGH PRESSURE BUILDS INTO THE AREA
SCOURING OUT THE LOW LEVEL MOISTURE.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 53 70 54 73 / 100 30 10 10
HUTCHINSON 52 71 51 74 / 40 10 10 10
NEWTON 52 72 53 72 / 70 20 10 10
ELDORADO 53 70 52 71 / 100 30 10 20
WINFIELD-KWLD 54 69 56 75 / 100 50 20 20
RUSSELL 47 73 48 75 / 0 10 0 0
GREAT BEND 48 72 49 74 / 0 10 0 0
SALINA 48 74 50 73 / 0 10 0 10
MCPHERSON 51 72 51 74 / 30 10 0 10
COFFEYVILLE 56 67 59 70 / 90 50 20 30
CHANUTE 54 70 56 70 / 80 50 20 20
IOLA 54 70 56 70 / 70 40 20 20
PARSONS-KPPF 55 68 56 70 / 80 50 20 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1154 AM MDT WED SEP 12 2012
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 403 AM MDT WED SEP 12 2012
FORECAST PROBLEMS WILL BE PRECIPITATION TIMING/COVERAGE INTO
TOMORROW...HOW COOL TO MAKE HIGH TEMPERATURES THROUGH THURSDAY...
AND HOW COOL TO MAKE THE MINS THE NEXT THREE NIGHTS. SATELLITE
CONTINUING TO SHOW AN AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO
THE ATLANTIC. COMPLEX AND MODERATELY STRONG SHORTWAVE TROUGH MOVING
TOWARD THE AREA FROM THE SOUTHWEST. MID LEVEL MOISTURE HAS
INCREASED SIGNIFICANTLY FROM YESTERDAY WITH LOW LEVEL MOISTURE NOT
VERY PLENTIFUL. COLD FRONT IS CURRENTLY PLOWING THROUGH THE AREA.
AT JET LEVEL...THE NAM/CANADIAN WERE DOING SLIGHTLY BETTER THAN THE
ECMWF AND UKMET. THE GFS WAS A LITTLE TOO FAR EAST WITH THE UPPER
JET THAT WILL BE A MAIN PLAYER IN THE LIFT. AT MID LEVELS...MODELS
WERE HAVING TROUBLE CATCHING THE IMPORTANT DETAILS AND OVERALL
POSITION/STRENGTH OF THE INCOMING TROUGH. IN GENERAL THEY WERE TOO
DEEP AND/OR TOO FAST WITH THE TROUGH OVER THE SOUTHWEST PORTION OF
THE COUNTRY WITH THE NAM THE WORST OFFENDER. SATELLITE AND UPPER AIR
ANALYSIS WOULD SAY THE UKMET IS THE BEST RIGHT NOW. RUC WAS DOING
BEST WITH THE SHORT TERM FRONTAL POSITION AND WINDS FOLLOWED BY THE
NAM/CANADIAN. THE MODELS TENDED TO BE A LITTLE SLOW WITH THE FRONT.
THE GFS AND CANADIAN SEEM TO HAVE A DECENT HANDLE ON THE LOW LEVEL
THERMAL FIELD.
TODAY/TONIGHT...JET LIFT IS SLOWER TO ARRIVE THAN WHAT WAS SHOWN
YESTERDAY. BY 00Z IT LOOKS LIKE IT IS CLOSE TO OR OVER THE
NORTHWEST CORNER OF THE FORECAST AREA. THE JET LIFT REALLY DOES NOT
GET STRONG UNTIL BETWEEN 00Z TO 06Z IN THE NORTHWEST HALF GOING BY
THE SLIGHTLY FASTER SOLUTIONS. IT IS POSSIBLE THAT IT COULD BE
SLIGHTLY LATER. MOST OF THE MODELS ARE STILL SHOWING GOOD JET
SUPPORT/LIFT OVER THE CENTRAL AND SOUTHEAST PORTION OF THE AREA
BETWEEN 06Z AND 12Z. ALSO SYNOPTIC SCALE AND MESOSCALE FORCING
DOES NOT ARRIVE UNTIL LATER IN THE AFTERNOON.
MID LEVEL MOISTURE IS INCREASING ACROSS THE AREA. HOWEVER...LOW
LEVELS REMAIN INITIALLY DRY. SEEING RAINFALL INCREASE IN COVERAGE
AND INTENSITY ALONG THE FRONT RANGE OF COLORADO AT THIS TIME. SINCE
DEEPER MOISTURE AND LIFT IS SLOWER TO ARRIVE...SLOWED THE ARRIVAL
OF THE RAINFALL AND HIGHER POPS UNTIL LATER THIS AFTERNOON. ALL
MODELS MATCH UP WELL WITH THEIR SYNOPTIC SCALE/MESOSCALE FORCING...
QPF FIELDS...LOCAL POP PROGRAM OUTPUT...AND GEFS/SREF PROBABILITY FOR
MEASURABLE FIELDS SO HAVE HIGHER CONFIDENCE THAT MOST OF THE AREA
WILL RECEIVE MEASURABLE RAINFALL. IT WILL BY NO MEANS BE A SOAKER BUT
MEASURABLE LOOKS PRETTY GOOD.
THE HIGHEST CHANCE/COVERAGE OF PRECIPITATION WILL BE TONIGHT FIRST IN
THE NORTHWEST HALF THEN TRANSITION TO THE SOUTHEAST HALF AFTER 06Z.
TOOK THE MENTION OF THUNDERSTORMS OUT SINCE NOTHING INDICATES ANY
INSTABILITY AT THIS TIME. WHAT IS INTERESTING IS THIS IS
SUBTROPICAL MOISTURE AND PWS COME UP TO 1 TO 1.5 INCHES. EVEN THOUGH
NOT CONVECTIVE IN NATURE...THETA-E LAPSE RATES WOULD INDICATE A
GOOD RESPONSE TO THE LIFT.
CLOUD COVER IS THICKENING ALREADY WITH COLD AIR ADVECTION CONTINUING
THROUGH THE DAY FOLLOWED BY PRECIPITATION INCREASING THIS AFTERNOON.
SO KEPT THE COOL MAXES FOR THE DAY WITH GUIDANCE IN REASONABLE
AGREEMENT. WILL WATCH TRENDS FOR THE REST OF THE SHIFT AND MAY MAKE
FURTHER ADJUSTMENTS BASE ON HOW CURRENT TEMPERATURES ARE DOING.
DEPENDING ON HOW FAST IT CLEARS OUT TONIGHT...IT COULD GET A LITTLE
COOL. LOOKS LIKE THE NORTHERN PORTION WILL AND MADE MINS UP THERE
COOLER.
THURSDAY...PER ANALYSIS AND CURRENT TRENDS...IT IS POSSIBLE THAT THE
MODELS COULD BE TOO FAST IN BRINGING IN AND GETTING RID OF THE
PRECIPITATION. THERE LOOKS TO STILL BE SOME JET LIFT OCCURRING IN THE
SOUTHEAST PORTION THIRD OF THE AREA BETWEEN 12Z AND 18Z. IT WILL BE
CLOSE BUT THERE STILL BE SOME LINGERING JET LIFT NEAR 00Z. SO
SLOWLY DECREASED THE PRECIPITATION THROUGH THE DAY...ENDING BY 00Z.
DEPENDING ON HOW FAST THE CLEARING OCCURS WILL AFFECT THE MAXES. AT
THIS TIME IT LOOKS LIKE THE NORTH WILL BE THE WARMEST. TENDED TO
COMPROMISED BETWEEN THE WARMEST/COOLEST GUIDANCE ACCOUNTING FOR
THE POSSIBILITY OF SLOWER CLEARING.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 403 AM MDT WED SEP 12 2012
THURSDAY NIGHT...LOOKS LIKE THE AREA WILL CLEAR OUT BY 06Z. LOW
DEWPOINTS SINCE UPSTREAM. POSSIBLE THAT DEWPOINTS COULD BE LOWER
THAN WHAT I HAVE IN THERE. WIND FIELD GOES LIGHT AS WELL. KEPT THE
COOL MINS AND POSSIBLE THEY MAY NEED TO BE LOWERED. IF THEY ARE
LOWERED ANY MORE...SOME LOW LYING AREAS MAY SEE PATCHY FROST. NOT
READY TO GO THERE YET THOUGH.
FRIDAY/FRIDAY NIGHT...RIDGE BUILDS IN WITH PLENTY OF SUN. HOWEVER
MODELS CUT OFF A LOW ON THE WESTERN END OF THE TROUGH THAT HAS
MOVED THROUGH. THIS WILL KEEP AN EASTERLY FLOW ALOFT OVER THE AREA.
PLUS IF CIRCULATION ENDS UP BEING FURTHER NORTH...MORE CLOUDS AND
COOLER TEMPERATURES COULD BE IN STORE. AT THIS TIME HAVE THE
WARMEST IN THE NORTH AND COOLEST IN THE SOUTH WITH A TREND OF
COMPROMISING BETWEEN THE WARMER AND COOLER GUIDANCE. INDICATIONS
ARE THAT WIND FIELD COULD BE LIGHT WITH LOW DEWPOINTS STILL IN
PLACE. COULD BE ANOTHER COOL NIGHT WITH MINS POSSIBLY LOWER THAN I
HAVE THEM.
SATURDAY THROUGH TUESDAY...FLOW ALOFT WILL BE NORTHWESTERLY THROUGH
MOST OF THE PERIOD...WITH A TROUGH DIGGING OVER THE REGION LATE IN
THE PERIOD. A COLD FRONT WILL MOVE THROUGH THE AREA ON
MONDAY...BRINGING WITH IT A CHANCE FOR SHOWERS AND THUNDERSTORMS.
STILL A LOT OF UNCERTAINTY REGARDING TEMPERATURES ON MONDAY...BUT
BETTER AGREEMENT THAN YESTERDAY WITH THE TIMING OF THE FRONT.
GUIDANCE IS TRENDING COOLER...SO HAVE ADJUSTED HIGHS DOWNWARD A FEW
DEGREES ACROSS MUCH OF THE REGION. TEMPERATURES DURING THE PERIOD
WILL BE WARMEST ON SUNDAY WITH HIGH TEMPERATURES NEAR NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1150 AM MDT WED SEP 12 2012
SOME BRIEF VISIBILITY REDUCTIONS IN BLOWING DUST HAVE BEEN NOTED AT
BOTH KGLD AND KMCK WITH GUSTY NORTH WINDS BEHIND A COLD FRONT...THIS
MAY CONTINUE UNTIL MID AFTERNOON AS WINDS DIMINISH. CEILINGS WILL
GRADUALLY LOWER THROUGH THE AFTERNOON AT BOTH TERMINALS AS SCATTERED
RAIN SHOWERS ASSOCIATED WITH UPPER SYSTEM MOVES IN FROM COLORADO.
LOW LEVEL ARE STARTING OUT RATHER DRY...SO MVFR MAY NOT BE REACHED
UNTIL MID OR LATE AFTERNOON...AND IFR CEILINGS POSSIBLE TONIGHT AS
LIGHT RAIN CONTINUES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DDT/BULLER
LONG TERM...BULLER/CJS
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
548 AM MDT WED SEP 12 2012
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 403 AM MDT WED SEP 12 2012
FORECAST PROBLEMS WILL BE PRECIPITATION TIMING/COVERAGE INTO
TOMORROW...HOW COOL TO MAKE HIGH TEMPERATURES THROUGH THURSDAY...
AND HOW COOL TO MAKE THE MINS THE NEXT THREE NIGHTS. SATELLITE
CONTINUING TO SHOW AN AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO
THE ATLANTIC. COMPLEX AND MODERATELY STRONG SHORTWAVE TROUGH MOVING
TOWARD THE AREA FROM THE SOUTHWEST. MID LEVEL MOISTURE HAS
INCREASED SIGNIFICANTLY FROM YESTERDAY WITH LOW LEVEL MOISTURE NOT
VERY PLENTIFUL. COLD FRONT IS CURRENTLY PLOWING THROUGH THE AREA.
AT JET LEVEL...THE NAM/CANADIAN WERE DOING SLIGHTLY BETTER THAN THE
ECMWF AND UKMET. THE GFS WAS A LITTLE TOO FAR EAST WITH THE UPPER
JET THAT WILL BE A MAIN PLAYER IN THE LIFT. AT MID LEVELS...MODELS
WERE HAVING TROUBLE CATCHING THE IMPORTANT DETAILS AND OVERALL
POSITION/STRENGTH OF THE INCOMING TROUGH. IN GENERAL THEY WERE TOO
DEEP AND/OR TOO FAST WITH THE TROUGH OVER THE SOUTHWEST PORTION OF
THE COUNTRY WITH THE NAM THE WORST OFFENDER. SATELLITE AND UPPER AIR
ANALYSIS WOULD SAY THE UKMET IS THE BEST RIGHT NOW. RUC WAS DOING
BEST WITH THE SHORT TERM FRONTAL POSITION AND WINDS FOLLOWED BY THE
NAM/CANADIAN. THE MODELS TENDED TO BE A LITTLE SLOW WITH THE FRONT.
THE GFS AND CANADIAN SEEM TO HAVE A DECENT HANDLE ON THE LOW LEVEL
THERMAL FIELD.
TODAY/TONIGHT...JET LIFT IS SLOWER TO ARRIVE THAN WHAT WAS SHOWN
YESTERDAY. BY 00Z IT LOOKS LIKE IT IS CLOSE TO OR OVER THE
NORTHWEST CORNER OF THE FORECAST AREA. THE JET LIFT REALLY DOES NOT
GET STRONG UNTIL BETWEEN 00Z TO 06Z IN THE NORTHWEST HALF GOING BY
THE SLIGHTLY FASTER SOLUTIONS. IT IS POSSIBLE THAT IT COULD BE
SLIGHTLY LATER. MOST OF THE MODELS ARE STILL SHOWING GOOD JET
SUPPORT/LIFT OVER THE CENTRAL AND SOUTHEAST PORTION OF THE AREA
BETWEEN 06Z AND 12Z. ALSO SYNOPTIC SCALE AND MESOSCALE FORCING
DOES NOT ARRIVE UNTIL LATER IN THE AFTERNOON.
MID LEVEL MOISTURE IS INCREASING ACROSS THE AREA. HOWEVER...LOW
LEVELS REMAIN INITIALLY DRY. SEEING RAINFALL INCREASE IN COVERAGE
AND INTENSITY ALONG THE FRONT RANGE OF COLORADO AT THIS TIME. SINCE
DEEPER MOISTURE AND LIFT IS SLOWER TO ARRIVE...SLOWED THE ARRIVAL
OF THE RAINFALL AND HIGHER POPS UNTIL LATER THIS AFTERNOON. ALL
MODELS MATCH UP WELL WITH THEIR SYNOPTIC SCALE/MESOSCALE FORCING...
QPF FIELDS...LOCAL POP PROGRAM OUTPUT...AND GEFS/SREF PROBABILITY FOR
MEASURABLE FIELDS SO HAVE HIGHER CONFIDENCE THAT MOST OF THE AREA
WILL RECEIVE MEASURABLE RAINFALL. IT WILL BY NO MEANS BE A SOAKER BUT
MEASURABLE LOOKS PRETTY GOOD.
THE HIGHEST CHANCE/COVERAGE OF PRECIPITATION WILL BE TONIGHT FIRST IN
THE NORTHWEST HALF THEN TRANSITION TO THE SOUTHEAST HALF AFTER 06Z.
TOOK THE MENTION OF THUNDERSTORMS OUT SINCE NOTHING INDICATES ANY
INSTABILITY AT THIS TIME. WHAT IS INTERESTING IS THIS IS
SUBTROPICAL MOISTURE AND PWS COME UP TO 1 TO 1.5 INCHES. EVEN THOUGH
NOT CONVECTIVE IN NATURE...THETA-E LAPSE RATES WOULD INDICATE A
GOOD RESPONSE TO THE LIFT.
CLOUD COVER IS THICKENING ALREADY WITH COLD AIR ADVECTION CONTINUING
THROUGH THE DAY FOLLOWED BY PRECIPITATION INCREASING THIS AFTERNOON.
SO KEPT THE COOL MAXES FOR THE DAY WITH GUIDANCE IN REASONABLE
AGREEMENT. WILL WATCH TRENDS FOR THE REST OF THE SHIFT AND MAY MAKE
FURTHER ADJUSTMENTS BASE ON HOW CURRENT TEMPERATURES ARE DOING.
DEPENDING ON HOW FAST IT CLEARS OUT TONIGHT...IT COULD GET A LITTLE
COOL. LOOKS LIKE THE NORTHERN PORTION WILL AND MADE MINS UP THERE
COOLER.
THURSDAY...PER ANALYSIS AND CURRENT TRENDS...IT IS POSSIBLE THAT THE
MODELS COULD BE TOO FAST IN BRINGING IN AND GETTING RID OF THE
PRECIPITATION. THERE LOOKS TO STILL BE SOME JET LIFT OCCURRING IN THE
SOUTHEAST PORTION THIRD OF THE AREA BETWEEN 12Z AND 18Z. IT WILL BE
CLOSE BUT THERE STILL BE SOME LINGERING JET LIFT NEAR 00Z. SO
SLOWLY DECREASED THE PRECIPITATION THROUGH THE DAY...ENDING BY 00Z.
DEPENDING ON HOW FAST THE CLEARING OCCURS WILL AFFECT THE MAXES. AT
THIS TIME IT LOOKS LIKE THE NORTH WILL BE THE WARMEST. TENDED TO
COMPROMISED BETWEEN THE WARMEST/COOLEST GUIDANCE ACCOUNTING FOR
THE POSSIBILITY OF SLOWER CLEARING.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 403 AM MDT WED SEP 12 2012
THURSDAY NIGHT...LOOKS LIKE THE AREA WILL CLEAR OUT BY 06Z. LOW
DEWPOINTS SINCE UPSTREAM. POSSIBLE THAT DEWPOINTS COULD BE LOWER
THAN WHAT I HAVE IN THERE. WIND FIELD GOES LIGHT AS WELL. KEPT THE
COOL MINS AND POSSIBLE THEY MAY NEED TO BE LOWERED. IF THEY ARE
LOWERED ANY MORE...SOME LOW LYING AREAS MAY SEE PATCHY FROST. NOT
READY TO GO THERE YET THOUGH.
FRIDAY/FRIDAY NIGHT...RIDGE BUILDS IN WITH PLENTY OF SUN. HOWEVER
MODELS CUT OFF A LOW ON THE WESTERN END OF THE TROUGH THAT HAS
MOVED THROUGH. THIS WILL KEEP AN EASTERLY FLOW ALOFT OVER THE AREA.
PLUS IF CIRCULATION ENDS UP BEING FURTHER NORTH...MORE CLOUDS AND
COOLER TEMPERATURES COULD BE IN STORE. AT THIS TIME HAVE THE
WARMEST IN THE NORTH AND COOLEST IN THE SOUTH WITH A TREND OF
COMPROMISING BETWEEN THE WARMER AND COOLER GUIDANCE. INDICATIONS
ARE THAT WIND FIELD COULD BE LIGHT WITH LOW DEWPOINTS STILL IN
PLACE. COULD BE ANOTHER COOL NIGHT WITH MINS POSSIBLY LOWER THAN I
HAVE THEM.
SATURDAY THROUGH TUESDAY...FLOW ALOFT WILL BE NORTHWESTERLY THROUGH
MOST OF THE PERIOD...WITH A TROUGH DIGGING OVER THE REGION LATE IN
THE PERIOD. A COLD FRONT WILL MOVE THROUGH THE AREA ON
MONDAY...BRINGING WITH IT A CHANCE FOR SHOWERS AND THUNDERSTORMS.
STILL A LOT OF UNCERTAINTY REGARDING TEMPERATURES ON MONDAY...BUT
BETTER AGREEMENT THAN YESTERDAY WITH THE TIMING OF THE FRONT.
GUIDANCE IS TRENDING COOLER...SO HAVE ADJUSTED HIGHS DOWNWARD A FEW
DEGREES ACROSS MUCH OF THE REGION. TEMPERATURES DURING THE PERIOD
WILL BE WARMEST ON SUNDAY WITH HIGH TEMPERATURES NEAR NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 545 AM MDT WED SEP 12 2012
COMPLICATED SET OF TAFS. INCOMING SHORTWAVE TROUGH AND UPPER JET
WILL CAUSE CLOUDS DECKS TO LOWER AND PRECIPITATION TO GRADUALLY
SPREAD OVER THE AREA. GREATEST CHANCE FOR PRECIPITATION WILL BEGIN
LATE THIS AFTERNOON AND CONTINUE THROUGH THE EVENING HOURS. MVFR
TO OCCASIONAL IFR CEILINGS AND VISIBILITIES WILL OCCUR FROM LATE
THIS AFTERNOON THROUGH THE EVENING. AFTER PRECIPITATION ENDS...IFR
TO LIFR CEILING WILL OCCUR UNTIL TOWARD THE END OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DDT/BULLER
LONG TERM...BULLER/CJS
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
403 AM MDT WED SEP 12 2012
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 403 AM MDT WED SEP 12 2012
FORECAST PROBLEMS WILL BE PRECIPITATION TIMING/COVERAGE INTO
TOMORROW...HOW COOL TO MAKE HIGH TEMPERATURES THROUGH THURSDAY...
AND HOW COOL TO MAKE THE MINS THE NEXT THREE NIGHTS. SATELLITE
CONTINUING TO SHOW AN AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO
THE ATLANTIC. COMPLEX AND MODERATELY STRONG SHORTWAVE TROUGH MOVING
TOWARD THE AREA FROM THE SOUTHWEST. MID LEVEL MOISTURE HAS
INCREASED SIGNIFICANTLY FROM YESTERDAY WITH LOW LEVEL MOISTURE NOT
VERY PLENTIFUL. COLD FRONT IS CURRENTLY PLOWING THROUGH THE AREA.
AT JET LEVEL...THE NAM/CANADIAN WERE DOING SLIGHTLY BETTER THAN THE
ECMWF AND UKMET. THE GFS WAS A LITTLE TOO FAR EAST WITH THE UPPER
JET THAT WILL BE A MAIN PLAYER IN THE LIFT. AT MID LEVELS...MODELS
WERE HAVING TROUBLE CATCHING THE IMPORTANT DETAILS AND OVERALL
POSITION/STRENGTH OF THE INCOMING TROUGH. IN GENERAL THEY WERE TOO
DEEP AND/OR TOO FAST WITH THE TROUGH OVER THE SOUTHWEST PORTION OF
THE COUNTRY WITH THE NAM THE WORST OFFENDER. SATELLITE AND UPPER AIR
ANALYSIS WOULD SAY THE UKMET IS THE BEST RIGHT NOW. RUC WAS DOING
BEST WITH THE SHORT TERM FRONTAL POSITION AND WINDS FOLLOWED BY THE
NAM/CANADIAN. THE MODELS TENDED TO BE A LITTLE SLOW WITH THE FRONT.
THE GFS AND CANADIAN SEEM TO HAVE A DECENT HANDLE ON THE LOW LEVEL
THERMAL FIELD.
TODAY/TONIGHT...JET LIFT IS SLOWER TO ARRIVE THAN WHAT WAS SHOWN
YESTERDAY. BY 00Z IT LOOKS LIKE IT IS CLOSE TO OR OVER THE
NORTHWEST CORNER OF THE FORECAST AREA. THE JET LIFT REALLY DOES NOT
GET STRONG UNTIL BETWEEN 00Z TO 06Z IN THE NORTHWEST HALF GOING BY
THE SLIGHTLY FASTER SOLUTIONS. IT IS POSSIBLE THAT IT COULD BE
SLIGHTLY LATER. MOST OF THE MODELS ARE STILL SHOWING GOOD JET
SUPPORT/LIFT OVER THE CENTRAL AND SOUTHEAST PORTION OF THE AREA
BETWEEN 06Z AND 12Z. ALSO SYNOPTIC SCALE AND MESOSCALE FORCING
DOES NOT ARRIVE UNTIL LATER IN THE AFTERNOON.
MID LEVEL MOISTURE IS INCREASING ACROSS THE AREA. HOWEVER...LOW
LEVELS REMAIN INITIALLY DRY. SEEING RAINFALL INCREASE IN COVERAGE
AND INTENSITY ALONG THE FRONT RANGE OF COLORADO AT THIS TIME. SINCE
DEEPER MOISTURE AND LIFT IS SLOWER TO ARRIVE...SLOWED THE ARRIVAL
OF THE RAINFALL AND HIGHER POPS UNTIL LATER THIS AFTERNOON. ALL
MODELS MATCH UP WELL WITH THEIR SYNOPTIC SCALE/MESOSCALE FORCING...
QPF FIELDS...LOCAL POP PROGRAM OUTPUT...AND GEFS/SREF PROBABILITY FOR
MEASURABLE FIELDS SO HAVE HIGHER CONFIDENCE THAT MOST OF THE AREA
WILL RECEIVE MEASURABLE RAINFALL. IT WILL BY NO MEANS BE A SOAKER BUT
MEASURABLE LOOKS PRETTY GOOD.
THE HIGHEST CHANCE/COVERAGE OF PRECIPITATION WILL BE TONIGHT FIRST IN
THE NORTHWEST HALF THEN TRANSITION TO THE SOUTHEAST HALF AFTER 06Z.
TOOK THE MENTION OF THUNDERSTORMS OUT SINCE NOTHING INDICATES ANY
INSTABILITY AT THIS TIME. WHAT IS INTERESTING IS THIS IS
SUBTROPICAL MOISTURE AND PWS COME UP TO 1 TO 1.5 INCHES. EVEN THOUGH
NOT CONVECTIVE IN NATURE...THETA-E LAPSE RATES WOULD INDICATE A
GOOD RESPONSE TO THE LIFT.
CLOUD COVER IS THICKENING ALREADY WITH COLD AIR ADVECTION CONTINUING
THROUGH THE DAY FOLLOWED BY PRECIPITATION INCREASING THIS AFTERNOON.
SO KEPT THE COOL MAXES FOR THE DAY WITH GUIDANCE IN REASONABLE
AGREEMENT. WILL WATCH TRENDS FOR THE REST OF THE SHIFT AND MAY MAKE
FURTHER ADJUSTMENTS BASE ON HOW CURRENT TEMPERATURES ARE DOING.
DEPENDING ON HOW FAST IT CLEARS OUT TONIGHT...IT COULD GET A LITTLE
COOL. LOOKS LIKE THE NORTHERN PORTION WILL AND MADE MINS UP THERE
COOLER.
THURSDAY...PER ANALYSIS AND CURRENT TRENDS...IT IS POSSIBLE THAT THE
MODELS COULD BE TOO FAST IN BRINGING IN AND GETTING RID OF THE
PRECIPITATION. THERE LOOKS TO STILL BE SOME JET LIFT OCCURRING IN THE
SOUTHEAST PORTION THIRD OF THE AREA BETWEEN 12Z AND 18Z. IT WILL BE
CLOSE BUT THERE STILL BE SOME LINGERING JET LIFT NEAR 00Z. SO
SLOWLY DECREASED THE PRECIPITATION THROUGH THE DAY...ENDING BY 00Z.
DEPENDING ON HOW FAST THE CLEARING OCCURS WILL AFFECT THE MAXES. AT
THIS TIME IT LOOKS LIKE THE NORTH WILL BE THE WARMEST. TENDED TO
COMPROMISED BETWEEN THE WARMEST/COOLEST GUIDANCE ACCOUNTING FOR
THE POSSIBILITY OF SLOWER CLEARING.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 403 AM MDT WED SEP 12 2012
THURSDAY NIGHT...LOOKS LIKE THE AREA WILL CLEAR OUT BY 06Z. LOW
DEWPOINTS SINCE UPSTREAM. POSSIBLE THAT DEWPOINTS COULD BE LOWER
THAN WHAT I HAVE IN THERE. WIND FIELD GOES LIGHT AS WELL. KEPT THE
COOL MINS AND POSSIBLE THEY MAY NEED TO BE LOWERED. IF THEY ARE
LOWERED ANY MORE...SOME LOW LYING AREAS MAY SEE PATCHY FROST. NOT
READY TO GO THERE YET THOUGH.
FRIDAY/FRIDAY NIGHT...RIDGE BUILDS IN WITH PLENTY OF SUN. HOWEVER
MODELS CUT OFF A LOW ON THE WESTERN END OF THE TROUGH THAT HAS
MOVED THROUGH. THIS WILL KEEP AN EASTERLY FLOW ALOFT OVER THE AREA.
PLUS IF CIRCULATION ENDS UP BEING FURTHER NORTH...MORE CLOUDS AND
COOLER TEMPERATURES COULD BE IN STORE. AT THIS TIME HAVE THE
WARMEST IN THE NORTH AND COOLEST IN THE SOUTH WITH A TREND OF
COMPROMISING BETWEEN THE WARMER AND COOLER GUIDANCE. INDICATIONS
ARE THAT WIND FIELD COULD BE LIGHT WITH LOW DEWPOINTS STILL IN
PLACE. COULD BE ANOTHER COOL NIGHT WITH MINS POSSIBLY LOWER THAN I
HAVE THEM.
SATURDAY THROUGH TUESDAY...FLOW ALOFT WILL BE NORTHWESTERLY THROUGH
MOST OF THE PERIOD...WITH A TROUGH DIGGING OVER THE REGION LATE IN
THE PERIOD. A COLD FRONT WILL MOVE THROUGH THE AREA ON
MONDAY...BRINGING WITH IT A CHANCE FOR SHOWERS AND THUNDERSTORMS.
STILL A LOT OF UNCERTAINTY REGARDING TEMPERATURES ON MONDAY...BUT
BETTER AGREEMENT THAN YESTERDAY WITH THE TIMING OF THE FRONT.
GUIDANCE IS TRENDING COOLER...SO HAVE ADJUSTED HIGHS DOWNWARD A FEW
DEGREES ACROSS MUCH OF THE REGION. TEMPERATURES DURING THE PERIOD
WILL BE WARMEST ON SUNDAY WITH HIGH TEMPERATURES NEAR NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1105 PM MDT TUE SEP 11 2012
VFR CONDITIONS WILL PERSIST THROUGH 22Z OR SO FOR BOTH TERMINALS.
DURING THIS TIME PERIOD NORTH TO NORTHEAST WINDS OF 20-25KTS WITH
GUSTS TO 35 KTS EXPECTED. AFTER 22Z CIGS WILL START TO DECREASE AS
LOW LEVEL MOISTURE INCREASES FROM THE WEST. MVFR/IFR CIGS EXPECTED
BY 00Z CONTINUING THROUGH 06Z. RAIN SHOWERS EXPECTED AROUND 00Z
WITH A STEADY RAIN AND SOME FOG/BR EXPECTED IN THE 01Z-05Z TIME
FRAME BEFORE TRANSITIONING BACK TO A MORE SHOWERY TYPE AS THE
FORCING AND MOISTURE SLOWLY MOVE EAST OF BOTH TERMINALS. THE
STRONG AND GUSTY NORTH TO NORTHEAST WINDS SHOULD TAPER OFF
SIGNIFICANTLY BY 00Z OR SHORTLY THEREAFTER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DDT/BULLER
LONG TERM...BULLER/CJS
AVIATION...DDT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1110 PM MDT TUE SEP 11 2012
.UPDATE...
ISSUED AT 837 PM MDT TUE SEP 11 2012
00Z NAM/RUC AND 23Z HRRR SUPPORT PREVIOUS THINKING THAT WINDS
INITIALLY BEHIND THE COLD FRONT WILL GUST IN THE 30 TO 40 MPH
RANGE WITH SOME GUSTS TO 45 MPH POSSIBLE IN FAR EASTERN COLORADO
FOR A FEW HOURS. HAVE ALSO PULLED POPS FOR MOST OF THE NIGHT WITH
JUST A SMALL CHANCE ACROSS THE NORTHWEST CORNER OF THE AREA BY
12Z.
WILL CONTINUE TO MONITOR TRENDS AND ADJUST GRIDS AS NECESSARY.
UPDATE ISSUED AT 533 PM MDT TUE SEP 11 2012
WILL AWAIT 00Z DATA BEFORE MAKING AN UPDATE THIS EVENING. PRIMARY
CONCERN TONIGHT IS TIMING OF THE COLD FRONT AND POST FRONTAL WINDS
BEHIND IT.
AT PRESENT TIME 18Z/21Z DATA SUGGESTING WIND GUSTS OF 35 TO 45 MPH
WILL BE COMMON GENERALLY ALONG AND WEST OF THE CO/KS BORDER AFTER
03Z WHERE 3 HOUR PRESSURE RISES OF 5-7 MB EXPECTED. NOT SURE WE
WILL REACH 3 HOUR REQUIREMENT OF WIND GUSTS OF 45 MPH OR GREATER
FOR A WIND ADVISORY SO NO HIGHLITES EXPECTED PRESENTLY.
OTHER CONCERN IS THAT SLIGHT CHANCE/LOW CHANCE POPS THROUGH
MIDNIGHT MAY BE A BIT OVERDONE GIVEN THE BETTER MOISTURE AND JET
ENERGY REMAINS TO OUR WEST. FROM 06Z-12Z MAY NEED TO BUMP UP POPS
ACROSS THE FAR WEST/NORTHWEST WHERE THE MOISTURE AND JET ENERGY
FINALLY ARRIVES WHILE FURTHER EAST MAY NEED TO BRING POPS DOWN
GIVEN A DECREASING AVAILABILITY OF MOISTURE AND LIFT.
WILL FINE TUNE THE FORECAST ONCE THE 00Z DATA STARTS TO ARRIVE.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 136 PM MDT TUE SEP 11 2012
A TROUGH CAN BE SEEN ON WATER VAPOR OVER SOUTHERN NEVADA. THE LATEST
VISIBLE SATELLITE SHOWING A MOSTLY CLEAR SKY EAST OF THE ROCKIES.
THE 18Z SURFACE CHART SHOWS A TROUGH EXTENDING FROM EASTERN NEW
MEXICO ACROSS EASTERN COLORADO TO EASTERN SOUTH DAKOTA.
THE TROUGH OVER THE GREAT BASIN WILL MOVE EAST INTO THE ROCKIES
TONIGHT AND WEDNESDAY. THE SURFACE TROUGH WILL SHIFT SOUTHEAST
TONIGHT AND WEDNESDAY. A COLD FRONT WILL MOVE INTO THE PLAINS BEHIND
THE TROUGH LATE TONIGHT AND WEDNESDAY. POPS WILL INCREASE FROM
SLIGHT CHANCE FOR THUNDERSTORMS THIS EVENING NEAR THE TROUGH IN
EASTERN COLORADO TO CHANCES FOR SHOWERS AS INSTABILITY DECREASES
BEHIND THE FRONT OVERNIGHT. CHANCE POPS WILL BE ACROSS THE ENTIRE FA
WEDNESDAY AS BETTER RH AND DYNAMICS MOVE THROUGH. THE NORTHWEST FA
WILL HAVE LIKELY POPS WHERE MOISTURE IS MOST FAVORABLE. ONCE AGAIN
INSTABILITY IS LACKING SO WILL LIMIT THUNDER TO ISOLATED.
MIN TEMPERATURES WILL COOL DOWN TO THE MID 50S WEST TO THE LOWER 60S
EAST. MAX TEMPERATURES WEDNESDAY WILL RANGE FROM THE MID TO UPPER
60S BEHIND THE FRONT AND LOWER TO MID 70S NEAR THE FRONT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 210 PM MDT TUE SEP 11 2012
MAIN TROUGH AXIS IS STILL EXPECTED TO PASS OVER OUR CWA WED
NIGHT...WITH THE BEST LARGE SCALE ASCENT AND MOISTURE IN PLACE
ACROSS THE CWA WED EVENING. SHOWERS AND ISOLATED THUNDERSTORMS WILL
INCREASE IN COVERAGE OVER THE AREA THROUGH THE EVENING...AND THEN
MOVE EAST/SOUTHEAST WITH TROUGH. COVERAGE SHOULD THEN DECREASE
THROUGH THURSDAY MORNING...THOUGH A FEW LINGERING SHOWERS COULDNT BE
RULED OUT IN THE SOUTH THURSDAY AFTERNOON. WITH ALL AVAILABLE
GUIDANCE NOW IN GENERAL AGREEMENT ON TIMING/POSITION OF PRECIP I
FELT COMFORTABLE INCREASING POPS TO CATEGORICAL CATEGORY WED
EVENING ACROSS THE AREA. THERE IS STILL SOME SPREAD REGARDING
RAINFALL AMOUNTS...HOWEVER MUCH OF THE AREA SHOULD GET AT LEAST A
FEW TENTHS OF AN INCH OF RAIN...MORE DEPENDING ON WHERE THE
MODERATE BANDS OF PRECIP SET UP. TEMPERATURE OF THURSDAY SHOULD BE
IN THE 60S ACROSS MUCH OF THE AREA...WITH LOW 70S IN THE NORTH
WHERE CLEARING IS EXPECTED EARLIEST.
WITH A DRY/STABLE/COOL AIRMASS IN PLACE THU NIGHT WE COULD SEE ONE
OF THE COOLER NIGHTS SINCE LAST SPRING. CURRENT FORECAST HIGHS IN
THE UPPER 30S/LOW 40S ACROSS THE AREA IS IN LINE WITH WHAT OCCUR ED
LAST SAT NIGHT...HOWEVER WITH TD VALUES ADVERTISED TO DROP INTO THE
LOW 30S BY SOME GUIDANCE...COLDER TEMPERATURES ARE CERTAINLY
POSSIBLE.
DRY CONDITIONS AND MODERATING TEMPERATURES ARE EXPECTED FRIDAY INTO
NEXT WEEKEND AS A SHORTWAVE RIDGE BUILDS BACK OVER THE AREA.
TEMPERATURES WILL REMAIN BELOW NORMAL IN THE 70S FRIDAY AND NEAR
NORMAL IN THE LOW 80S SATURDAY. HIGHS ON SUNDAY MAY REACH THE UPPER
80S AT A FEW LOCATIONS WITH GOOD WAA AHEAD OF NEXT APPROACHING
SYSTEM. THE GOOD NEWS IS THAT THIS WOULD BE THE WARMEST DAY OF THE
ENTIRE FORECAST PERIOD...SO NO 100 DEGREE DAYS ON THIS FORECAST
CYCLE. ANOTHER UPPER LEVEL TROUGH IS EXPECTED TO MOVE ACROSS THE
NORTHERN PLAINS EARLY NEXT WEEK...BRINGING ANOTHER SHOT OF
PRECIPITATION AND COOLER TEMPERATURES BACK TO THE REGION. THERE IS
STILL A LOT OF UNCERTAINTY IN REGARDS TO THE TIMING/TRACK OF THIS
SYSTEM...HOWEVER IT DOES APPEAR TO SHOW A LOT OF SIMILARITIES TO THE
SYSTEM WE ARE EXPECTING THIS WEEK. I KEPT SLIGHT CHANCE/CHANCE POPS
IN PLACE MON AND MONDAY NIGHT WHERE CURRENT GUIDANCE IS TIMING
PRECIP WITH THIS SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1105 PM MDT TUE SEP 11 2012
VFR CONDITIONS WILL PERSIST THROUGH 22Z OR SO FOR BOTH TERMINALS.
DURING THIS TIME PERIOD NORTH TO NORTHEAST WINDS OF 20-25KTS WITH
GUSTS TO 35 KTS EXPECTED. AFTER 22Z CIGS WILL START TO DECREASE AS
LOW LEVEL MOISTURE INCREASES FROM THE WEST. MVFR/IFR CIGS EXPECTED
BY 00Z CONTINUING THROUGH 06Z. RAIN SHOWERS EXPECTED AROUND 00Z
WITH A STEADY RAIN AND SOME FOG/BR EXPECTED IN THE 01Z-05Z TIME
FRAME BEFORE TRANSITIONING BACK TO A MORE SHOWERY TYPE AS THE
FORCING AND MOISTURE SLOWLY MOVE EAST OF BOTH TERMINALS. THE
STRONG AND GUSTY NORTH TO NORTHEAST WINDS SHOULD TAPER OFF
SIGNIFICANTLY BY 00Z OR SHORTLY THEREAFTER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...FS
LONG TERM...DR
AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1210 AM CDT WED SEP 12 2012
...UPDATED FOR THE 06Z TAF AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 104 PM CDT TUE SEP 11 2012
AN IMPRESSIVE CYCLONE WAS MATURING ALONG THE MANITOBA-SASKATCHEWAN
BORDER TODAY. RAP ANALYSIS SUGGESTED A COMPACT 110KT JET STREAK ON
THE IMMEDIATE SOUTHEAST SIDE OF THE CYCLONE OVER CENTRAL MANITOBA.
THE SURFACE WAS RESPONDING NICELY TO THIS WITH A 985MB SURFACE LOW
ANALYZED THROUGH SURFACE OBSERVATIONS. CLOSER TO HOME...A VERY
WEAK...SUBTLE MID LEVEL DISTURBANCE WAS MOVING ACROSS WESTERN KANSAS
INTO SOUTHERN NEBRASKA...WHICH WAS PRODUCING NOTHING MORE THAN A FEW
MID AND HIGH LEVEL CLOUDS ACROSS THE REGION. AT THE SURFACE...THE
COLD FRONT TIED TO THE CANADA STORM EXTENDED FROM NORTHEASTERN SOUTH
DAKOTA TO WESTERN NEBRASKA LATE THIS AFTERNOON. A FAIRLY TIGHT
PRESSURE GRADIENT AHEAD OF THIS FRONT (AND A LEE TROUGH ACROSS
EASTERN COLORADO AND FAR WESTERN KANSAS) RESULTED IN STRONG WINDS OF
20 TO 25 KNOTS ACROSS MUCH OF KANSAS...NEBRASKA...AND OKLAHOMA. A
VERY DRY ATMOSPHERE WAS PRESENT IN THE WARM (AND WINDY) SECTOR WITH
DEWPOINTS MAINLY IN THE UPPER 30S TO LOWER 40S ACROSS WESTERN KANSAS
AND NEBRASKA AND THE TEXAS PANHANDLE. AS SURFACE TEMPERATURES
CONTINUED TO RISE THROUGH THE LOWER 90S...RELATIVE HUMIDITY WAS
FALLING TO 15 TO 20 PERCENT...RESULTING IN WIDESPREAD NEAR CRITICAL
TO CRITICAL FIRE WEATHER CONDITIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 313 PM CDT TUE SEP 11 2012
A COLLECTION OF SUBTROPICAL SHORTWAVE PERTURBATIONS OVER THE DESERT
SOUTHWEST WILL CONTINUE ITS MOVEMENT NORTHEAST THROUGH THE EVENING
AND TONIGHT...APPROACHING SOUTHWEST COLORADO AND NORTHEAST NEW
MEXICO BY DAYBREAK WEDNESDAY. MEANWHILE...THE SURFACE COLD FRONT
TIED TO THE CANADA STORM WILL REACH ROUGHLY A LAMAR CO-HILL CITY
KS-LINCOLN NE LINE BY DAYBREAK. THROUGH THE NIGHT...LOW LEVEL
PRESSURE GRADIENT WILL KEEP WINDS UP IN THE 15 TO 20 KNOT RANGE
THROUGH THE NIGHT...AND AS A RESULT TEMPERATURES WILL ONLY FALL INTO
THE MID TO UPPER 60S FOR LOWS FOR MOST AREAS OF SOUTHWEST AND WEST
CENTRAL KANSAS. SOME AREAS OF CENTRAL AND SOUTH CENTRAL KANSAS WILL
SEE TEMPERATURES BOTTOMING OUT ONLY IN THE 68 TO 70 DEGREE RANGE.
THERE IS A SUBSTANTIAL HIGH TEMPERATURE FORECAST CHALLENGE
WEDNESDAY...ESPECIALLY ACROSS WEST CENTRAL KANSAS (NORTHWEST OF A
GARDEN CITY TO LACROSSE LINE)...AS THE FRONT WILL INITIATE COLD AIR
ADVECTION FROM THE NORTH IN THESE AREAS BY MIDDAY. THE QUESTION IS
HOW MUCH DIRECT INSOLATION WILL OFFSET THE INITIAL COLD
ADVECTION...AS OVERALL CLOUD COVER SHOULD STILL BE CONFINED TO AREAS
FARTHER NORTH DURING THE DIURNAL MAXIMUM OF THE AFTERNOON. AM
LEANING MORE TOWARD A COMPROMISE OF THE NAM12 AND ECMWF FOR 18Z AND
00Z COLD FRONT TIMING AND ASSOCIATED SURFACE TEMPERATURES. A LOW
LEVEL THERMAL RIDGE WILL EXTEND NORTHEASTWARD AHEAD OF THE
FRONT...WHICH BY EARLY TO MID AFTERNOON SHOULD EXTEND FROM ROUGHLY
MEADE TO BUCKLIN TO PRATT. ALONG AND SOUTHEAST OF THIS
LINE...AFTERNOON TEMPERATURES SHOULD REACH THE LOWER TO MID 90S.
CONVERGENCE ALONG THE FRONT AND SURFACE LOW...ESPECIALLY SOUTH OF
DODGE CITY TO THE OKLAHOMA BORDER...WILL LIKELY BE ENOUGH TO
INITIATE ONE OR TWO THUNDERSTORMS IN ENVIRONMENT OF ABOUT 600 TO 900
J/KG OF SURFACE BASED CAPE IN THE HOT AIRMASS WITH LIMITED SURFACE
MOISTURE. WILL CARRY 20 POPS IN THIS AREA (SOUTHEAST OF ROUGHLY
MEADE TO BUCKLIN TO PRATT). THE MAIN PRECIPITATION EVENT TIED TO
THE 800-700MB FRONT WILL BE AFTER THE WEDNESDAY (DAY) PERIOD.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 241 PM CDT TUE SEP 11 2012
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL TROUGH OF LOW PRESSURE
MOVING EAST OUT OF THE COLORADO ROCKIES INTO THE WESTERN HIGH PLAINS
WEDNESDAY NIGHT AND THURSDAY BRINGING A REASONABLE CHANCE FOR PRECIP
TO PORTIONS OF WESTERN AND CENTRAL KANSAS EARLY IN THE PERIOD. A
COLD FRONT ATTENDANT TO A LARGER SCALE UPPER LEVEL TROUGH
TRANSITIONING EAST OUT OF THE NORTHERN PLAINS INTO THE GREAT LAKES
REGION, WILL PUSH SOUTHEAST INTO WESTERN KANSAS WEDNESDAY NIGHT
AHEAD OF THE UPPER LEVEL SHORTWAVE. AMPLE LOW LEVEL MOISTURE IS
EXPECTED TO POOL AHEAD OF THE APPROACHING FRONT WITH H85 DEWPOINTS
UP AROUND 10C IN CENTRAL AND WESTERN KANSAS AS INDICATED BY THE GEM,
GFS, AND ECMWF. HOWEVER, MODEL SOUNDINGS SHOW A FAIRLY WEAK FLOW
ALOFT ACROSS WESTERN KANSAS INITIALLY, BUT GRADUALLY INCREASING AS
AN UPPER LEVEL JET AXIS BEGINS TO FINALLY EDGE SOUTHEASTWARD ACROSS
NEBRASKA WITH A RIGHT ENTRANCE REGION JUST NOSING INTO KANSAS BY
EARLY THURSDAY MORNING. ADDITIONALLY, THE SOUNDINGS SHOW A LACK OF
STRONG INSTABILITY (CAPE) LATE WEDNESDAY NIGHT INTO EARLY THURSDAY
WITH NEAR SATURATED PROFILES. IN FACT, ALL MODELS INDICATE THE BEST
CHANCE FOR PRECIP IN ASSOCIATION WITH POST-FRONTAL H7 FRONTOGENESIS
BANDING LATE WEDNESDAY NIGHT INTO EARLY THURSDAY ACROSS MUCH OF
CENTRAL AND SOUTHWEST KANSAS. WILL KEEP 60 TO 70 POPS IN ACROSS
MUCH OF THE FORECAST AREA LATE WEDNESDAY NIGHT INTO EARLY THURSDAY.
TEMPERATURES WILL BE BELOW NORMAL THURSDAY IN WAKE OF THE COLD
FRONTAL PASSAGE EXPECTED LATE WEDNESDAY. ADDITIONALLY, INCREASED
LOW/MID LEVEL CLOUDS AND EXPECTED WIDESPREAD PRECIP EARLY TO MID DAY
THURSDAY WILL LIMIT CLIMBING TEMPERATURES. THE GEM, GFS, AND ECMWF
SHOW COOLER AIR FILTERING SOUTH INTO WESTERN KANSAS WITH H85
TEMPERATURES DROPPING DOWN TO AROUND 10C TO 12C ACROSS CENTRAL AND
SOUTHWEST KANSAS. AGAIN, WITH INCREASED CLOUDS AND LINGERING PRECIP
HIGHS COULD STRUGGLE TO REACH UP INTO THE 60S(F). THE BETTER CHANCE
FOR WARMER TEMPERATURES MAY COME ACROSS WEST CENTRAL AND EXTREME
SOUTHWEST KANSAS WHERE CLOUDS MAY POTENTIALLY SCATTER THURSDAY
AFTERNOON AS THE UPPER LEVEL SYSTEM PUSHES EAST. A GRADUAL WARMING
TREND IS THEN LIKELY THROUGH THE WEEKEND AS WEAK UPPER LEVEL RIDGING
BRIEFLY DEVELOPS ACROSS THE INTERMOUNTAIN WEST BEFORE BREAKING DOWN
SATURDAY AND SUNDAY. NEAR THE SURFACE, A GENERAL SOUTHEASTERLY FLOW
WILL DEVELOP FRIDAY AS SURFACE HIGH PRESSURE MIGRATES EAST INTO THE
OHIO RIVER VALLEY. MEANWHILE, MORE OF A SOUTHERLY COMPONENT WILL
TAKE OVER SATURDAY INTO SUNDAY AS A LEE SIDE TROUGH OF LOW PRESSURE
DEVELOPS IN EASTERN COLORADO HELPING TO ADVECT SLIGHTLY WARMER AIR
INTO THE REGION SUPPORTING THE WARMING TREND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1203 AM CDT WED SEP 12 2012
THE TAFS WILL REFLECT BREEZY SOUTH TO SOUTHEAST WINDS THROUGH
ABOUT 10Z ALONG WITH CLEAR SKIES. WINDS WILL BECOME SOUTHWEST
AROUND 14KTS TOWARD MORNING AS SURFACE TROUGH ADVANCES EAST FROM
COLORADO. A COLD FRONT IS COMING SOUTHEAST AND WILL SHIFT WINDS TO
THE NORTH-NORTHEAST AFTER 15 TO 16Z WEDNESDAY. THERE IS A SLIGHT
CHANCE FOR THUNDERSTORMS WEDNESDAY AFTERNOON, BUT THE BETTER CHANCE
APPEARS TO BE EAST OF ALL TAF SITES. THUS, CONVECTION WILL NOT BE
MENTIONED UNTIL LATER TAF ISSUANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 55 65 48 72 / 80 80 20 0
GCK 52 67 47 72 / 80 60 10 0
EHA 52 66 49 74 / 80 70 10 0
LBL 53 66 49 72 / 70 70 20 0
HYS 53 67 45 72 / 70 50 10 0
P28 63 65 52 72 / 70 80 30 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1159 PM EDT THU SEP 13 2012
.SYNOPSIS...
ISSUED AT 427 PM EDT THU SEP 13 2012
A COLD FRONT WILL BRING RAIN TO THE AREA OVERNIGHT. THIS WILL BE
FOLLOWED BY COOLER BUT STILL SEASONABLE TEMPERATURES AROUND 70 ON
FRIDAY. AFTER A GRADUAL WARMING TREND TO THE MID 70S THROUGH
MONDAY...ANOTHER COLD FRONT WILL BRING A CHANCE FOR RAIN SHOWERS
MONDAY NIGHT AND TUESDAY ALONG WITH HIGH TEMPERATURES IN THE 60S.
&&
.UPDATE...
ISSUED AT 1025 PM EDT THU SEP 13 2012
UPDATE TO EXPIRE SCA NORTH OF GRAND HAVEN. ALSO TWEAKED POPS SLIGHTLY.
UPDATE ISSUED AT 424 PM EDT THU SEP 13 2012
FORECAST WAS UPDATED TO ACCOUNT FOR THE SHOWERS DEVELOPING FROM
LANSING TO NEAR KALAMAZOO.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 335 PM EDT THU SEP 13 2012
TREND ON THE RAIN FOR TONIGHT HAS BEEN DOWN IN TERMS OF AMOUNTS FOR
SEVERAL MODEL RUNS NOW. REGIONAL RADAR LOOPS DO NOT LOOK OVERLY
IMPRESSIVE EITHER. STILL...EXPECT A BAND OF RAIN TO WORK THROUGH THE
ENTIRE FORECAST AREA BRINGING AMOUNTS ON THE ORDER OF A TENTH OR TWO
AT MOST LOCATIONS. THE FAR SOUTHEAST TOWARD JACKSON MAY SEE SLIGHTLY
HIGHER AMOUNTS. PRECIPITATION IS BEING FOCUSED BY THE RIGHT ENTRANCE
REGION OF A 300MB JET. CURRENT THINKING BASED ON SPC AND NSSL WRF
MODEL RUNS AND THE TRENDS IN THE LATEST HRRR IS THAT THE RAIN WILL
BE OFF TO THE EAST OF THE FORECAST AREA BY 12Z ON FRIDAY.
LOOKING FOR SOME MORNING CUMULUS DEVELOPMENT ON FRIDAY WITH DRIER
AIR TAKING OVER DURING THE AFTERNOON. IN GENERAL EXPECTING A PARTLY
CLOUDY TO MOSTLY SUNNY FORECAST FOR FRIDAY. FEEL THE AIR MASS
WILL BE TOO DRY FOR ANY SHOWER DEVELOPMENT OFF THE LAKE DESPITE
DELTA T/S IN THE MIDDLE TEENS C.
FRIDAY NIGHT THROUGH SATURDAY NIGHT LOOKS QUIET AND DRY WITH HIGH
PRESSURE IN CONTROL.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 335 PM EDT THU SEP 13 2012
FAIR WX WITH SEASONABLY MILD TEMPS IS ANTICIPATED SUNDAY THROUGH
MONDAY AFTERNOON IN A SOUTHERLY FLOW WAA PATTERN IN ADVANCE OF THE
APPROACHING COLD FRONT. THAT FRONT WILL BRING SOME SHOWERS MONDAY
NIGHT THROUGH TUESDAY. LAKE EFFECT CLOUDS AND SHOWERS ARE
ANTICIPATED TUESDAY NIGHT INTO WEDNESDAY AS H8 TEMPS (BRIEFLY) DIP
DOWN TO AROUND 0 TO -1 C BEFORE MODERATING.
IT WILL TURN COOLER TUESDAY THROUGH MIDWEEK AS A FAIRLY DEEP
LONGWAVE UPPER LEVEL TROUGH DEVELOPS FROM THE UPPER MIDWEST TO GREAT
LAKES REGIONS. A SECONDARY COLD FRONT WILL BRING THE CHANCE FOR
ADDITIONAL SHOWERS WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1153 PM EDT THU SEP 13 2012
LOW LEVEL MOISTURE ASSOCIATED WITH THE BAND OF RAIN MOVING THROUGH
HAS CREATED SOME IFR ROUGHLY KLAN TO KAZO...EAST. WITH THE BAND OF
RAIN ADVANCING EAST...THERE STILL COULD BE SOME IFR THROUGH ABOUT 09Z.
CLEARING BEHIND THE RAIN BAND...MAY ALLOW FOR GROUND FOG TO
FORM...BUT DRIER AIR WAS WORKING IN...SO NOT CONFIDENT ON THIS AT
THIS TIME. WILL MONITOR TRENDS IN THE NEXT FEW HRS.
MIXING ON FRI WILL ALLOW FOR SOME GUSTY WINDS...ESPECIALLY KGRR TO KMKG
&&
.MARINE...
ISSUED AT 335 PM EDT THU SEP 13 2012
HAVE OPTED TO KEEP THE CURRENT CONFIGURATION TO THE SMALL CRAFT
ADVISORIES WITH THE NORTH ENDING THIS EVENING AND THE SOUTH
OVERNIGHT. GRADIENT TURNS LAX TONIGHT IN THE WAKE OF FIRST FRONTAL
PASSAGE WHICH LEADS TO A DECAYING WAVE FIELD. WINDS INCREASE AGAIN
ON FRIDAY THOUGH IN THE WAKE OF A SECONDARY FRONT LATE TONIGHT.
WINDS WILL LIKELY NOSE UP TOWARDS 20 KNOTS FRIDAY WHICH SHOULD BUILD
A SOLID 3-5 FOOT WAVE FIELD DURING THE DAY. SO...RATHER THAN STRETCH
THE CURRENT SCA THROUGH TOMORROW THROUGH A 8-12 PERIOD OF QUIET
WAVES LATE TONIGHT AND TOMORROW MORNING OPTED TO LET THE CURRENT
HEADLINES EXPIRE TONIGHT. A NEW SCA WILL LIKELY BE NEED FOR FRIDAY
WITH THE OVERNIGHT FORECAST PACKAGE IF THE CURRENT FORECAST WINDS
HOLD.
&&
.HYDROLOGY...
ISSUED AT 335 PM EDT THU SEP 13 2012
NO HYDRO ISSUES ANTICIPATED WITH RAINFALL AMOUNTS PROBABLY ENDING UP
BELOW A THIRD OF AN INCH IN MANY AREAS TONIGHT. HIGHEST AMOUNTS WILL
BE IN THE FAR SOUTHEAST REACHES OF THE FORECAST AREA TOWARDS
JACKSON. RIVER LEVELS ARE LOW AND WELL WITHIN BANK. THE NEXT CHANCE
FOR RAIN DOES NOT COME UNTIL EARLY NEXT WEEK AFTER TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT FRIDAY FOR LMZ844>846.
&&
$$
UPDATE...JK
SYNOPSIS...TJT
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1025 PM EDT THU SEP 13 2012
.SYNOPSIS...
ISSUED AT 427 PM EDT THU SEP 13 2012
A COLD FRONT WILL BRING RAIN TO THE AREA OVERNIGHT. THIS WILL BE
FOLLOWED BY COOLER BUT STILL SEASONABLE TEMPERATURES AROUND 70 ON
FRIDAY. AFTER A GRADUAL WARMING TREND TO THE MID 70S THROUGH
MONDAY...ANOTHER COLD FRONT WILL BRING A CHANCE FOR RAIN SHOWERS
MONDAY NIGHT AND TUESDAY ALONG WITH HIGH TEMPERATURES IN THE 60S.
&&
.UPDATE...
ISSUED AT 1025 PM EDT THU SEP 13 2012
UPDATE TO EXPIRE SCA NORTH OF GRAND HAVEN. ALSO TWEAKED POPS SLIGHTLY.
UPDATE ISSUED AT 424 PM EDT THU SEP 13 2012
FORECAST WAS UPDATED TO ACCOUNT FOR THE SHOWERS DEVELOPING FROM
LANSING TO NEAR KALAMAZOO.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 335 PM EDT THU SEP 13 2012
TREND ON THE RAIN FOR TONIGHT HAS BEEN DOWN IN TERMS OF AMOUNTS FOR
SEVERAL MODEL RUNS NOW. REGIONAL RADAR LOOPS DO NOT LOOK OVERLY
IMPRESSIVE EITHER. STILL...EXPECT A BAND OF RAIN TO WORK THROUGH THE
ENTIRE FORECAST AREA BRINGING AMOUNTS ON THE ORDER OF A TENTH OR TWO
AT MOST LOCATIONS. THE FAR SOUTHEAST TOWARD JACKSON MAY SEE SLIGHTLY
HIGHER AMOUNTS. PRECIPITATION IS BEING FOCUSED BY THE RIGHT ENTRANCE
REGION OF A 300MB JET. CURRENT THINKING BASED ON SPC AND NSSL WRF
MODEL RUNS AND THE TRENDS IN THE LATEST HRRR IS THAT THE RAIN WILL
BE OFF TO THE EAST OF THE FORECAST AREA BY 12Z ON FRIDAY.
LOOKING FOR SOME MORNING CUMULUS DEVELOPMENT ON FRIDAY WITH DRIER
AIR TAKING OVER DURING THE AFTERNOON. IN GENERAL EXPECTING A PARTLY
CLOUDY TO MOSTLY SUNNY FORECAST FOR FRIDAY. FEEL THE AIR MASS
WILL BE TOO DRY FOR ANY SHOWER DEVELOPMENT OFF THE LAKE DESPITE
DELTA T/S IN THE MIDDLE TEENS C.
FRIDAY NIGHT THROUGH SATURDAY NIGHT LOOKS QUIET AND DRY WITH HIGH
PRESSURE IN CONTROL.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 335 PM EDT THU SEP 13 2012
FAIR WX WITH SEASONABLY MILD TEMPS IS ANTICIPATED SUNDAY THROUGH
MONDAY AFTERNOON IN A SOUTHERLY FLOW WAA PATTERN IN ADVANCE OF THE
APPROACHING COLD FRONT. THAT FRONT WILL BRING SOME SHOWERS MONDAY
NIGHT THROUGH TUESDAY. LAKE EFFECT CLOUDS AND SHOWERS ARE
ANTICIPATED TUESDAY NIGHT INTO WEDNESDAY AS H8 TEMPS (BRIEFLY) DIP
DOWN TO AROUND 0 TO -1 C BEFORE MODERATING.
IT WILL TURN COOLER TUESDAY THROUGH MIDWEEK AS A FAIRLY DEEP
LONGWAVE UPPER LEVEL TROUGH DEVELOPS FROM THE UPPER MIDWEST TO GREAT
LAKES REGIONS. A SECONDARY COLD FRONT WILL BRING THE CHANCE FOR
ADDITIONAL SHOWERS WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 742 PM EDT THU SEP 13 2012
AN ELEVATED RISK FOR IFR CLOUDS TO DEVELOP EXISTS ON THE BACKSIDE
OF THE BAND OF RAIN PULLING THROUGH. IF THIS HAPPENS IT WILL
LIKELY BE AFTER 04Z. NOT CONFIDENT ENOUGH TO ADD IT TO THE
FORECAST AT THIS TIME. MONITOR TRENDS CLOSELY THROUGH THE EVENING.
MVFR CLOUDS AND VSBYS ARE MORE LIKELY TO ACCOMPANY THE PASSAGE OF
THIS SYSTEM. GUSTY WINDS WILL DEVELOP ON FRI...LIKELY AFTER 15Z
WITH SOME VALUES OVER 25 KNOTS LIKELY.
&&
.MARINE...
ISSUED AT 335 PM EDT THU SEP 13 2012
HAVE OPTED TO KEEP THE CURRENT CONFIGURATION TO THE SMALL CRAFT
ADVISORIES WITH THE NORTH ENDING THIS EVENING AND THE SOUTH
OVERNIGHT. GRADIENT TURNS LAX TONIGHT IN THE WAKE OF FIRST FRONTAL
PASSAGE WHICH LEADS TO A DECAYING WAVE FIELD. WINDS INCREASE AGAIN
ON FRIDAY THOUGH IN THE WAKE OF A SECONDARY FRONT LATE TONIGHT.
WINDS WILL LIKELY NOSE UP TOWARDS 20 KNOTS FRIDAY WHICH SHOULD BUILD
A SOLID 3-5 FOOT WAVE FIELD DURING THE DAY. SO...RATHER THAN STRETCH
THE CURRENT SCA THROUGH TOMORROW THROUGH A 8-12 PERIOD OF QUIET
WAVES LATE TONIGHT AND TOMORROW MORNING OPTED TO LET THE CURRENT
HEADLINES EXPIRE TONIGHT. A NEW SCA WILL LIKELY BE NEED FOR FRIDAY
WITH THE OVERNIGHT FORECAST PACKAGE IF THE CURRENT FORECAST WINDS
HOLD.
&&
.HYDROLOGY...
ISSUED AT 335 PM EDT THU SEP 13 2012
NO HYDRO ISSUES ANTICIPATED WITH RAINFALL AMOUNTS PROBABLY ENDING UP
BELOW A THIRD OF AN INCH IN MANY AREAS TONIGHT. HIGHEST AMOUNTS WILL
BE IN THE FAR SOUTHEAST REACHES OF THE FORECAST AREA TOWARDS
JACKSON. RIVER LEVELS ARE LOW AND WELL WITHIN BANK. THE NEXT CHANCE
FOR RAIN DOES NOT COME UNTIL EARLY NEXT WEEK AFTER TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT FRIDAY FOR LMZ844>846.
&&
$$
UPDATE...JK
SYNOPSIS...TJT
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
745 PM EDT THU SEP 13 2012
.SYNOPSIS...
ISSUED AT 427 PM EDT THU SEP 13 2012
A COLD FRONT WILL BRING RAIN TO THE AREA OVERNIGHT. THIS WILL BE
FOLLOWED BY COOLER BUT STILL SEASONABLE TEMPERATURES AROUND 70 ON
FRIDAY. AFTER A GRADUAL WARMING TREND TO THE MID 70S THROUGH
MONDAY...ANOTHER COLD FRONT WILL BRING A CHANCE FOR RAIN SHOWERS
MONDAY NIGHT AND TUESDAY ALONG WITH HIGH TEMPERATURES IN THE 60S.
&&
.UPDATE...
ISSUED AT 424 PM EDT THU SEP 13 2012
FORECAST WAS UPDATED TO ACCOUNT FOR THE SHOWERS DEVELOPING FROM
LANSING TO NEAR KALAMAZOO.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 335 PM EDT THU SEP 13 2012
TREND ON THE RAIN FOR TONIGHT HAS BEEN DOWN IN TERMS OF AMOUNTS FOR
SEVERAL MODEL RUNS NOW. REGIONAL RADAR LOOPS DO NOT LOOK OVERLY
IMPRESSIVE EITHER. STILL...EXPECT A BAND OF RAIN TO WORK THROUGH THE
ENTIRE FORECAST AREA BRINGING AMOUNTS ON THE ORDER OF A TENTH OR TWO
AT MOST LOCATIONS. THE FAR SOUTHEAST TOWARD JACKSON MAY SEE SLIGHTLY
HIGHER AMOUNTS. PRECIPITATION IS BEING FOCUSED BY THE RIGHT ENTRANCE
REGION OF A 300MB JET. CURRENT THINKING BASED ON SPC AND NSSL WRF
MODEL RUNS AND THE TRENDS IN THE LATEST HRRR IS THAT THE RAIN WILL
BE OFF TO THE EAST OF THE FORECAST AREA BY 12Z ON FRIDAY.
LOOKING FOR SOME MORNING CUMULUS DEVELOPMENT ON FRIDAY WITH DRIER
AIR TAKING OVER DURING THE AFTERNOON. IN GENERAL EXPECTING A PARTLY
CLOUDY TO MOSTLY SUNNY FORECAST FOR FRIDAY. FEEL THE AIR MASS
WILL BE TOO DRY FOR ANY SHOWER DEVELOPMENT OFF THE LAKE DESPITE
DELTA T/S IN THE MIDDLE TEENS C.
FRIDAY NIGHT THROUGH SATURDAY NIGHT LOOKS QUIET AND DRY WITH HIGH
PRESSURE IN CONTROL.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 335 PM EDT THU SEP 13 2012
FAIR WX WITH SEASONABLY MILD TEMPS IS ANTICIPATED SUNDAY THROUGH
MONDAY AFTERNOON IN A SOUTHERLY FLOW WAA PATTERN IN ADVANCE OF THE
APPROACHING COLD FRONT. THAT FRONT WILL BRING SOME SHOWERS MONDAY
NIGHT THROUGH TUESDAY. LAKE EFFECT CLOUDS AND SHOWERS ARE
ANTICIPATED TUESDAY NIGHT INTO WEDNESDAY AS H8 TEMPS (BRIEFLY) DIP
DOWN TO AROUND 0 TO -1 C BEFORE MODERATING.
IT WILL TURN COOLER TUESDAY THROUGH MIDWEEK AS A FAIRLY DEEP
LONGWAVE UPPER LEVEL TROUGH DEVELOPS FROM THE UPPER MIDWEST TO GREAT
LAKES REGIONS. A SECONDARY COLD FRONT WILL BRING THE CHANCE FOR
ADDITIONAL SHOWERS WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 742 PM EDT THU SEP 13 2012
AN ELEVATED RISK FOR IFR CLOUDS TO DEVELOP EXISTS ON THE BACKSIDE
OF THE BAND OF RAIN PULLING THROUGH. IF THIS HAPPENS IT WILL
LIKELY BE AFTER 04Z. NOT CONFIDENT ENOUGH TO ADD IT TO THE
FORECAST AT THIS TIME. MONITOR TRENDS CLOSELY THROUGH THE EVENING.
MVFR CLOUDS AND VSBYS ARE MORE LIKELY TO ACCOMPANY THE PASSAGE OF
THIS SYSTEM. GUSTY WINDS WILL DEVELOP ON FRI...LIKELY AFTER 15Z
WITH SOME VALUES OVER 25 KNOTS LIKELY.
&&
.MARINE...
ISSUED AT 335 PM EDT THU SEP 13 2012
HAVE OPTED TO KEEP THE CURRENT CONFIGURATION TO THE SMALL CRAFT
ADVISORIES WITH THE NORTH ENDING THIS EVENING AND THE SOUTH
OVERNIGHT. GRADIENT TURNS LAX TONIGHT IN THE WAKE OF FIRST FRONTAL
PASSAGE WHICH LEADS TO A DECAYING WAVE FIELD. WINDS INCREASE AGAIN
ON FRIDAY THOUGH IN THE WAKE OF A SECONDARY FRONT LATE TONIGHT.
WINDS WILL LIKELY NOSE UP TOWARDS 20 KNOTS FRIDAY WHICH SHOULD BUILD
A SOLID 3-5 FOOT WAVE FIELD DURING THE DAY. SO...RATHER THAN STRETCH
THE CURRENT SCA THROUGH TOMORROW THROUGH A 8-12 PERIOD OF QUIET
WAVES LATE TONIGHT AND TOMORROW MORNING OPTED TO LET THE CURRENT
HEADLINES EXPIRE TONIGHT. A NEW SCA WILL LIKELY BE NEED FOR FRIDAY
WITH THE OVERNIGHT FORECAST PACKAGE IF THE CURRENT FORECAST WINDS
HOLD.
&&
.HYDROLOGY...
ISSUED AT 335 PM EDT THU SEP 13 2012
NO HYDRO ISSUES ANTICIPATED WITH RAINFALL AMOUNTS PROBABLY ENDING UP
BELOW A THIRD OF AN INCH IN MANY AREAS TONIGHT. HIGHEST AMOUNTS WILL
BE IN THE FAR SOUTHEAST REACHES OF THE FORECAST AREA TOWARDS
JACKSON. RIVER LEVELS ARE LOW AND WELL WITHIN BANK. THE NEXT CHANCE
FOR RAIN DOES NOT COME UNTIL EARLY NEXT WEEK AFTER TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ847>849.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT FRIDAY FOR LMZ844>846.
&&
$$
UPDATE...MJS
SYNOPSIS...TJT
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1230 PM CDT WED SEP 12 2012
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
QUITE A DIFFERENCE A DAY MAKES WITH EXPECTED TEMPERATURES TODAY AT
LEAST 20 DEGREES COOLER THAN YESTERDAY. CDFNT NOW PASSING ACROSS
THE METRO WITH TEMPS FALLING A GOOD 10 DEGREES IN AN HOUR OR TWO IN
WAKE OF FROPA. WITH BLANKET OF POST FRONTAL CLOUDS DON`T EXPECT MUCH
IN THE WAY OF TEMPERATURE RECOVERY TODAY. COOLING IN WAKE OF FRONT
IS ALSO BEING AIDED BY VERY LOW DEW POINT DEPRESSIONS YIELDING HIGH
EVAPORATIVE COOLING ACROSS AREAS WHICH HAVE RECEIVED LIGHT PRECIP
OVERNIGHT.
-RA AND EVEN SOME ISOL THUNDER REMAINS IN A SW-NE BAND ACROSS SODAK
THEN ACROSS CENTRAL MN IN PLUME OF ELEVATED MOISTURE. PRECIP
AMOUNTS HAVE GENERALLY BEEN A FEW HUNDREDTHS OF AN INCH...BUT ARND
.10 AT BENSON...APPLETON AND MADISON SO FAR. HRRR HAS BEEN DOING A
PRETTY GOOD JOB ON HANDLING THIS AREA OF PCPN WHICH HAS SOME SUPPORT
FROM RIGHT ENTRANCE REGION OF UPPER JET. INCREASED POPS FOR THE
MORNING ACROSS CENTRAL MN.
ANOTHER AREA OF SHWRS AND ISOL THUNDER HAS ALSO BEEN BEEN DEVELOPING
IN NW IA BACK INTO NEB. THIS AREA SHOULD CONTINUE TO DEVELOP DURING
THE DAY TODAY AS UPPER WAVE LIFTS OUT CO BACKING MID LEVEL WINDS AND
GENERATING FAVORABLE UPGLIDGE AROUND THE 305K SURFACE. INCREASED
POPS MAINLY ACRS S MN INTO THE KEAU AREA FOR LATER THIS MORNING AND
AFTN.
FOR THURSDAY A SHARP AND FAST MOVING UPPER TROF DIVES OUT OF THE
PRAIRIE PROVINCES OF CANADA TO NEAR NW CORNER MN BY 12Z AND INTO WI
BY 00Z THURSDAY. NOT MUCH MOISTURE AVAILABLE FOR PCPN...BUT
CONSIDERING PATH OF THIS FEATURE ACROSS AREA DURING THE DAYLIGHT AND
B24 500MB TEMPS...IT IS WORTHY OF A MENTION OF SLIGHT CHC POPS AND
ISOL THUNDER.
MODERATING TEMPERATURES OVER THE WEEKEND AS SOUTHERLY FLOW DEVELOPS
AHEAD OF NEXT IMPRESSIVE LOOKING COLD FRONT. FRONT COMES ACROSS
AREA SUNDAY NIGHT MONDAY BRINGING A CHANCE POPS AND SOME QUITE
CHILLY AIR AS 1000-500 MB THICKNESS DROPS TO 540DM ACROSS N MN.
LOOKING LIKE COOL START TO THE UPCOMING WEEK AS WE GET DEEP INTO NW
FLOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
BAND OF LIGHT RAIN OVER SOUTHERN MINNESOTA...SHOULD DROP SOUTH THIS
AFTERNOON...ENDING LAST AT KEAU. CLEARING THEREAFTER. IF IT CLEARS
FAST ENOUGH IN THE EAST...COULD SEE SOME FOG DEVELOP...IN THOSE
SEEING THE MOST RAIN....MAINLY WESTERN WISCONSIN. WILL LEAVE OUT FOR
NOW. NEXT SYSTEM MOVES INTO THE AREA THURSDAY AFTERNOON...WITH MID
CLOUDS AGAIN. LOWER LEVELS REMAIN DRY...SO ONLY SMALL CHANCE OF A
SHOWER POSSIBLE ACROSS CENTRAL MN. NORTHERLY WINDS OVER THE SOUTH
WITH WEST/NORTHWEST WINDS OVER THE NORTHERN CWA...AS DRIER AIR WORKS
INTO THE AREA. COULD SEE SOME GUSTS AROUND 20 MPH NORTHWEST INTO THE
AFTERNOON.
KMSP...LIGHT RAIN SHOWERS THROUGH ABOUT 22Z AND CEILINGS REMAIN VFR
THROUGH THE PERIOD. SHOULD SEE CLEARING THIS EVENING AS SYSTEM
EXITS. NEXT TROUGH SWINGS INTO THE AREA THU AFTERNOON. WILL DRAW
IN SOME MID CLOUDS BUT WILL REMAIN DRY FOR NOW. WESTERLY WIND WITH
RAIN BAND...DECREASING THIS EVENING AND INCREASING AGAIN THURSDAY
MORNING AND BECOMING NORTHWEST AS NEXT TROUGH MOVES THROUGH.
/OUTLOOK FOR KMSP/
.THURSDAY...VFR. ISOLD AFTN SHRA POSSIBLE. WINDS NW AT 05-10 KTS.
.FRIDAY...VFR. 5-10KT NW WINDS BECOMING SW.
.SATURDAY...VFR. WINDS S AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/DE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
649 AM CDT WED SEP 12 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
QUITE A DIFFERENCE A DAY MAKES WITH EXPECTED TEMPERATURES TODAY AT
LEAST 20 DEGREES COOLER THAN YESTERDAY. CDFNT NOW PASSING ACROSS
THE METRO WITH TEMPS FALLING A GOOD 10 DEGREES IN AN HOUR OR TWO IN
WAKE OF FROPA. WITH BLANKET OF POST FRONTAL CLOUDS DON`T EXPECT MUCH
IN THE WAY OF TEMPERATURE RECOVERY TODAY. COOLING IN WAKE OF FRONT
IS ALSO BEING AIDED BY VERY LOW DEW POINT DEPRESSIONS YIELDING HIGH
EVAPORATIVE COOLING ACROSS AREAS WHICH HAVE RECEIVED LIGHT PRECIP
OVERNIGHT.
-RA AND EVEN SOME ISOL THUNDER REMAINS IN A SW-NE BAND ACROSS SODAK
THEN ACROSS CENTRAL MN IN PLUME OF ELEVATED MOISTURE. PRECIP
AMOUNTS HAVE GENERALLY BEEN A FEW HUNDREDTHS OF AN INCH...BUT ARND
.10 AT BENSON...APPLETON AND MADISON SO FAR. HRRR HAS BEEN DOING A
PRETTY GOOD JOB ON HANDLING THIS AREA OF PCPN WHICH HAS SOME SUPPORT
FROM RIGHT ENTRANCE REGION OF UPPER JET. INCREASED POPS FOR THE
MORNING ACROSS CENTRAL MN.
ANOTHER AREA OF SHWRS AND ISOL THUNDER HAS ALSO BEEN BEEN DEVELOPING
IN NW IA BACK INTO NEB. THIS AREA SHOULD CONTINUE TO DEVELOP DURING
THE DAY TODAY AS UPPER WAVE LIFTS OUT CO BACKING MID LEVEL WINDS AND
GENERATING FAVORABLE UPGLIDGE AROUND THE 305K SURFACE. INCREASED
POPS MAINLY ACRS S MN INTO THE KEAU AREA FOR LATER THIS MORNING AND
AFTN.
FOR THURSDAY A SHARP AND FAST MOVING UPPER TROF DIVES OUT OF THE
PRAIRIE PROVINCES OF CANADA TO NEAR NW CORNER MN BY 12Z AND INTO WI
BY 00Z THURSDAY. NOT MUCH MOISTURE AVAILABLE FOR PCPN...BUT
CONSIDERING PATH OF THIS FEATURE ACROSS AREA DURING THE DAYLIGHT AND
B24 500MB TEMPS...IT IS WORTHY OF A MENTION OF SLIGHT CHC POPS AND
ISOL THUNDER.
MODERATING TEMPERATURES OVER THE WEEKEND AS SOUTHERLY FLOW DEVELOPS
AHEAD OF NEXT IMPRESSIVE LOOKING COLD FRONT. FRONT COMES ACROSS
AREA SUNDAY NIGHT MONDAY BRINGING A CHANCE POPS AND SOME QUITE
CHILLY AIR AS 1000-500 MB THICKNESS DROPS TO 540DM ACROSS N MN.
LOOKING LIKE COOL START TO THE UPCOMING WEEK AS WE GET DEEP INTO NW
FLOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
COLD FRONT HAS NOW CLEARED ALL MPX TERMINAL...WITH SFC HIGH
BUILDING IN ITS A WAKE. SEEING PLENTY OF LIFT BEHIND THE FRONT
RESULTING IN TWO BANDS OF PRECIP...ONCE OVER WRN WI AND THE OTHER
FROM NE COLORADO UP TO WRN MN. IT IS THE WRN BATCH OF RAIN THAT
THE NAM AND VARIOUS HI-RES WRF RUNS HAVE PICKED UP ON WELL THIS
MORNING...SO FOLLOWED THESE SOLUTIONS FOR MOVING A BAND OF LIGHT
RAIN ACROSS ALL BUT STC/AXN TODAY. WRN WI TERMINALS WILL LIKELY SEE A
BRIEF BREAK BETWEEN CURRENT RAIN AND THIS WRN BAND OF PRECIP WHICH
WILL MOVE THROUGH THERE IN THE AFTERNOON. HIGH PRESSURE AT THE SFC
IS VERY DRY...SO EXPECT VIS/CIG TO REMAIN VFR THE WHOLE PERIOD.
TONIGHT...SKIES WILL BEGIN TO CLEAR FROM NW TO SE. WINDS WILL BE
NOWHERE NEAR AS STRONG TODAY...BUT WILL TEND TO THE W/NW DEPENDING
ON A TERMINALS LOCATION RELATIVE TO THE RIDGE AXIS.
KMSP...SHOULD START OUT DRY THIS MORNING AS THE FIELD SITS BETWEEN
BANDS OF FORCING. TIMED PRECIP IN TAF PRETTY CLOSE TO THE
NAM...WITH SEVERAL HOURS OF LIGHT RAIN EXPECTED FROM LATE THIS
MORNING THROUGH MUCH OF THE AFTERNOON. DESPITE ALL OF THE
PRECIP...ADVECTION OF VERY DRY AIR IN AT THE LOW LEVELS WILL KEEP
CIGS ABV 060 TODAY.
/OUTLOOK FOR KMSP/
.THURSDAY...VFR. ISOLD AFTN SHRA POSSIBLE. WINDS NW AT 05-10 KTS.
.FRIDAY...VFR. 5-10KT NW WINDS BECOMING SW.
.SATURDAY...VFR. WINDS S AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
300 AM CDT WED SEP 12 2012
.DISCUSSION...
QUITE A DIFFERENCE A DAY MAKES WITH EXPECTED TEMPERATURES TODAY AT
LEAST 20 DEGREES COOLER THAN YESTERDAY. CDFNT NOW PASSING ACROSS
THE METRO WITH TEMPS FALLING A GOOD 10 DEGREES IN AN HOUR OR TWO IN
WAKE OF FROPA. WITH BLANKET OF POSTFRONTAL CLOUDS DON`T EXPECT MUCH
IN THE WAY OF TEMPERATURE RECOVERY TODAY. COOLING IN WAKE OF FRONT
IS ALSO BEING AIDED BY VERY LOW DEW POINT DEPRESSIONS YEILDING HIGH
EVAPORATIVE COOLING ACROSS AREAS WHICH HAVE RECEIVED LIGHT PRECIP
OVERNIGHT.
-RA AND EVEN SOME ISOL THUNDER REMAINS IN A SW-NE BAND ACROSS SODAK
THEN ACROSS CENTRAL MN IN PLUME OF ELEVATED MOISTURE. PRECIP
AMOUNTS HAVE GENERALLY BEEN A FEW HUNDRETHS OF AN INCH...BUT ARND
.10 AT BENSON...APPLETON AND MADISON SO FAR. HRRR HAS BEEN DOING A
PRETTY GOOD JOB ON HANDLING THIS AREA OF PCPN WHICH HAS SOME SUPPORT
FROM RIGHT ENTRANCE REGION OF UPPER JET. INCREASED POPS FOR THE
MORNING ACROSS CENTRAL MN.
ANOTHER AREA OF SHWRS AND ISOL THUNDER HAS ALSO BEEN BEEN DEVELOPING
IN NW IA BACK INTO NEB. THIS AREA SHOULD CONTINUE TO DEVELOP DURING
THE DAY TODAY AS UPPER WAVE LIFTS OUT CO BACKING MID LEVEL WINDS AND
GENERATING FAVORABLE UPGLIDGE AROUND THE 305K SURFACE. INCREASED
POPS MAINLY ACRS S MN INTO THE KEAU AREA FOR LATER THIS MORNING AND
AFTN.
FOR THURSDAY A SHARP AND FAST MOVING UPPER TROF DIVES OUT OF THE
PRAIRIE PROVINCES OF CANADA TO NEAR NW CORNER MN BY 12Z AND INTO WI
BY 00Z THURSDAY. NOT MUCH MOISTURE AVAILABLE FOR PCPN...BUT
CONSIDERING PATH OF THIS FEATURE ACROSS AREA DURING THE DAYLIGHT AND
B24 500MB TEMPS...IT IS WORTHY OF A MENTION OF SLIGHT CHC POPS AND
ISOL THUNDER.
MODERATING TEMPERATURES OVER THE WEEKEND AS SOUTHERLY FLOW DEVELOPS
AHEAD OF NEXT IMPRESSIVE LOOKING COLD FRONT. FRONT COMES ACROSS
AREA SUNDAY NIGHT MONDAY BRINGING A CHANCE POPS AND SOME QUITE
CHILLY AIR AS 1000-500 MB THICKNESS DROPS TO 540DM ACROSS N MN.
LOOKING LIKE COOL START TO THE UPCOMING WEEK AS WE GET DEEP INTO NW
FLOW.
&&
.AVIATION.../06Z TAF ISSUANCE/
A STRONG COLD FRONT WILL CONTINUE TO MOVE THROUGH THE REGION
OVERNIGHT. SOUTHWESTERLY WINDS WILL BECOME NORTHWESTERLY AFTER
THE FRONT MOVES THROUGH. A FEW HIGH BASED SHOWERS WITH AN
OCCASIONAL LIGHTNING STRIKE ARE POSSIBLE AS WELL...BUT COVERAGE
WILL BE SCARCE AND ONLY INCLUDED VCSH IN THE TAFS. LATER TODAY
MORE WIDESPREAD SHOWERS WILL DEVELOP ALONG THE IA/WI/MN BORDER AND
COULD AFFECT KEAU.
KMSP...WINDS SHOULD SHIFT FROM SOUTHWEST TO NORTHWEST AROUND 05Z.
A FEW LIGHT SHOWERS ARE POSSIBLE AROUND 09Z...BUT BASES WILL BE
VERY HIGH AND NO VISBY RESTRICTIONS ARE EXPECTED. LATER THIS
AFTERNOON THE MAJORITY OF THE SHOWERS WILL BE SOUTH AND EAST OF
KMSP...SO HAVE LEFT OUT MENTION OF AFTERNOON SHOWERS IN THE TAFS.
/OUTLOOK FOR KMSP/
THURSDAY...VFR. WINDS NW AT 05G15KTS.
FRIDAY...VFR. WINDS NW AT 05KTS.
SATURDAY...VFR. WINDS SW AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BORGHOFF/BAP
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
911 PM CDT THU SEP 13 2012
.UPDATE...
ISSUED AT 901 PM CDT THU SEP 13 2012
WATCHING RADAR RETURNS DRY UP OVER CENTRAL AND WESTERN MISSOURI
ATTM. AM UNSURE YET HOW THIS WILL ALL UNFOLD DURING THE OVERNIGHT
HOURS THOUGH...RAP AND HRRR ARE SHOWING THAT THE PRECIP CURRENTLY
OVER EASTERN KANSAS WILL SPREAD EASTWARD OVER THE NEXT FEW HOURS
TO FILL IN BEHIND THE DRYING IN CENTRAL MO...AND CURRENT RADAR
TRENDS OVER EASTER KANSAS ARE STARTING TO SUPPORT THIS IDEA.
ADDITIONALLY...THE BRAND SPANKING NEW 14/00Z NAM IS ROLLING IN AND
IS INDICATING MORE OR LESS THE SAME THING. WILL GO AHEAD AND BUMP
UP POPS AFTER MIDNIGHT ALONG AND SOUTH OF THE I-70 CORRIDOR...AND
LINGER PRECIP INTO FRIDAY MORNING FROM THE STL METRO AREA SOUTH
AND EAST.
ISSUED AT 604 PM CDT THU SEP 13 2012
AM RECONFIGURING POPS FOR TONIGHT...INCREASING TO CATEGORICAL IN
THE NORTHEAST MO/WEST CENTRAL IL FOR THE FIRST FEW HOURS OF THE
FORECAST BASED ON RADAR TRENDS...AND DROPPING LIKELY POPS ACROSS MUCH
OF THE REST OF THE AREA THIS EVENING. ALL MODELS SHOW SOME DECENT
ISENTROPIC LIFT AS THE LOW LEVEL BAROCLINIC ZONE SLIPS SOUTHEAST
BEHIND THE FRONT SO WILL MARCH LIKELY POPS SLOWLY SOUTHEAST
THROUGH THE EVENING HOURS. 18Z NAM DROPS SOME PRETTY DECENT 925-850MB
FRONTOGENESIS DOWN THROUGH EASTERN MISSOURI AND SOUTHWEST ILLINOIS
OVERNIGHT BETWEEN 09Z AND 12Z FRIDAY MORNING SO WILL CONTINUE TO
MARCH THE LIKELIES SOUTHEAST THROUGH THE OVERNIGHT HOURS.
CARNEY
&&
.SHORT TERM...
ISSUED AT 308 PM CDT THU SEP 13 2012
(TONIGHT)
THE PRIMARY FCST ISSUES FOR TONIGHT ARE TEMPERATURE AND PCPN TRENDS.
A CDFNT WAS MOVING THROUGH MISSOURI AND ILLINOIS THIS AFTN WITH
EXTENSIVE CLOUDINESS AND SCT SHRA LOCATED BEHIND IT. A MARKED
TEMPERATURE CONTRAST WAS NOTED ACROSS THE FRONT AT 19Z WITH LOW TO
MID 80S IN THE MOSTLY CLEAR AREAS AHEAD OF THE BDRY AND LOW 50S TO
LOW 60S BENEATH THE POST-FRONTAL CLOUD SHIELD.
THE KEY FEATURE GOVERNING OVERNIGHT LOWS WILL BE THE DURATION /AND
HEIGHT/ OF CLOUD COVER. LOW-MID CLOUDS THAT PERSIST FOR MOST OF THE
NIGHT WOULD SUPPORT LESS OF A TEMPERATURE DROP THAN WOULD THINNER
CIRRUS OR CLR SKIES. CONDENSATION PRESSURE DEFICIT PLOTS FOR VARIOUS
LAYERS BETWEEN 850MB AND 500MB SUPPORT THE IDEA THAT ALL BUT THE FAR
NWRN PART OF THE CWA WILL REMAIN CLOUDY OVERNIGHT THEREFORE KEPT THE
COOLEST OVERNIGHT LOWS IN THE NWRN CWA.
ASIDE FROM A STRAY SPRINKLE OR TWO...NEARLY ALL OF THE PCPN HAS BEEN
POST-FRONTAL IN NATURE AND FREE OF LIGHTNING. ATTM IT LOOKS LIKE THE
AREA OF POST-FRONTAL SHRA SHOULD SLOWLY SHIFT SEWD WITH TIME BASED
ON MODEL DEPICTIONS OF H9/H85 FRONTOGENETICAL FORCING WITH LIMITED
INSTABILITY.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 309 PM CDT THU SEP 13 2012
(FRIDAY THROUGH THURSDAY)
WILL SEE SOME LINGERING LIGHT RAIN SHOWERS OVER SOUTHEAST MO AND
SOUTHERN IL AS SYSTEM EXITS REGION ON FRIDAY MORNING. WITH COOLER
AND DRIER AIR FILTERING IN TEMPS WILL STRUGGLE TO WARM UP MUCH.
HIGHS WILL BE IN THE LOW TO MID 70S...WITH THE COOLEST TEMPS SOUTH
DUE TO LINGERING CLOUD COVER IN THIS AREA.
FOR THE WEEKEND...A TRICKY FORECAST AS MOST MODELS NOW TRYING TO
DEVELOP SOME OVER RUNNING PCPN OVER SOUTHWESTERN MO ALONG OLD COLD
FRONTAL BOUNDARY LATE SATURDAY THROUGH SUNDAY. FOR NOW CONFIDENCE IS
LOW...SO JUST HAVE SLIGHT CHANCE POPS FOR FAR SOUTHWESTERN PORTIONS
OF FORECAST AREA SATURDAY NIGHT AND SUNDAY. AS FOR TEMPS...LOWS
FRIDAY NIGHT WILL BE IN THE UPPER 40S TO MID 50S. HIGHS THROUGH THE
WEEKEND WILL BE IN THE MID TO UPPER 70S.
BY LATE SUNDAY NIGHT...NEXT COLD FRONT BEGINS TO MOVE INTO MO. WILL
SEE FRONT MOVE INTO FORECAST AREA MONDAY WITH SOME DECENT
INSTABILITY AND MOISTURE...SO HAVE SHOWERS AND THUNDERSTORMS
POSSIBLE THROUGH MONDAY EVENING...BEFORE PCPN TAPERS OFF TOWARDS
DAYBREAK ON TUESDAY. HIGHS WILL BE IN THE MID TO UPPER 70S ON
MONDAY...BEFORE DROPPING OFF INTO THE MID 60S FAR NORTH TO THE LOW
70S FAR SOUTH ON TUESDAY. COLDEST NIGHT WILL BE TUESDAY NIGHT WITH
LOWS IN THE LOW TO MID 40S.
BEYOND THAT EXTENDED MODELS BRING IN ANOTHER COLD FRONT WEDNESDAY
NIGHT AND THURSDAY WITH ANOTHER CHANCE FOR SHOWERS.
BYRD
&&
.AVIATION...
ISSUED AT 650 PM CDT THU SEP 13 2012
CDFNT AT 23Z IS WELL DEFINED VIA A FINE LINE INDICATED BY AREA
RADARS...FROM JUST SE OF KTBN AND JUST SE OF SULLIVAN MO TO KCPS
TO ABOUT 20SM SE OF LITCHFIELD IL. VFR CONDITIONS WILL PREVAIL
AHEAD OF...AND FOR NEARLY 100SM BEHIND THE FRONT. AREAS OF LO MVFR
AND IFR CIGS DO EXIST FROM ABOUT 100SM BEHIND THE FRONT...
HOWEVER...WITH THEIR ABILITY TO SURIVE THE DAY BEING HELPED OUT
THE MOST WHERE IT WAS ABLE TO RAIN. THESE AREAS ARE CERTAINLY NOT
SOLID AS EVIDENCED BY THE UP AND DOWN CIGS AT BOTH KUIN AND KCOU.
STEADY N FLOW AT 1-2KFT WILL GRADUALLY VEER NE LATER TONIGHT AND
STILL MORE E-NE ON FRIDAY MORNING. THIS SHOULD ALLOW LO CIGS NEAR
A KUIN-KCOU AXIS TO CONTINUE TO ADVECT SWD AND PLAY A RELATIVELY
BRIEF ROLE THERE AS THEY CLEAR OUT BY LATER THIS EVENING...AND
THEN TURN SWWD...ALLOWING EVEN THE LOWER CLOUDS IN NRN IL TO PLAY
A ROLE IN WHAT STL METRO WILL SEE LATER TONIGHT. IT IS THE VEERING
OF THE WINDS AT EXPECTED CLOUD LEVEL THAT COULD ALLOW THESE LO
CIGS TO HAVE A MORE EXTENDED STAY ACROSS THE STL METRO SITES.
SOLID BAND OF RAIN WELL BEHIND THE FRONT FROM CHICAGO TO KC SHOULD
GRADUALLY THIN AND DRY OUT AS IT PUSHES SE...WITH SEVERAL HOURS AT
KUIN THIS EVENING...A COUPLE OR SO AT KCOU TOWARDS MIDNIGHT...AND
SHORT OF IT BEING INVIGORATED...PERHAPS JUST 20MINS OR LESS FOR
STL METRO. LO CIGS SHOULD CLEAR OUT OF STL METRO BY LATE FRIDAY
MORNING LEAVING BEHIND A STILL EXPANSIVE REGION OF HI CLOUDS.
SPECIFICS FOR KSTL...GUSTY N SFC WNDS TO DIMINISH LATER THIS
EVENING...EXPECTED ARRIVAL OF LO CLOUDS FROM THE N TOWARDS
MIDNIGHT WITH PERSISTENCE LIKELY THRU MID FRIDAY MORNING...COULD
SEE IFR CIGS EXPAND AND WILL WATCH CLOSELY AND MAY ADD IN BY THE
03Z UPDATE...PCPN FOR NOW TO BE BRIEF IN OCCURRENCE AROUND DAWN...
IMPROVEMENT TO VFR THEN EXPECTED BY MIDDAY IF NOT SOONER.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1236 PM CDT Wed Sep 12 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today through Friday...
A band of weak elevated instability ahead of a surface cold front in
central Nebraska and northwest Iowa this morning has fired up a few
very light showers across the northwest corner of the forecast area.
The HRRR indicates these showers may persist just ahead of the
boundary for a few hours before mixing begins to eliminate the
instability, so have added a small chance of very light showers to
the far northwest through late morning. For the rest of the day,
above normal temperatures and breezy south winds can be expected
again, especially across the southwestern corner of the CWA. Surface
low pressure at the base of a deep trough over the northern Rockies
will push eastward into central Kansas today, resulting in the
tighter pressure gradient in our southwest, and could also provide
additional forcing needed to fire up some isolated convection mainly
west of the forecast area late this afternoon. As the main trough
dives to the southeast, the surface cold front will push through
southeast Nebraska and western Iowa, arriving at the northwest
corner of the CWA by 00z. Surface-based instability will build ahead
of the front this afternoon, which may result in isolated convective
initiation along the boundary as it enters the forecast area. Any
isolated development that occurs in central Kansas may also build
eastward during the evening, eventually merging with precipitation
along the cold front. However, surface-based convection will likely
not sustain after sunset, and the bulk of precipitation should occur
behind the surface front as the main wave moves through.
Although showers still look likely through Thursday as the main
trough makes southeastward progress across the CWA, precipitation
chances will decrease as the upper wave weakens and the best energy
transitions further east, towards the Great Lakes region. Have
gradually decreased the chance of precipitation from Thursday
morning through Friday, and also lowered precipitation amounts as
rainfall becomes more scattered. As the wave weakens, it also slows
across the region, so have slowed the southeastward progress of
rainfall chances, especially Thursday night and Friday. Lingering
showers should exit the region altogether by early Friday afternoon.
Temperatures will fall dramatically following cold frontal passage
on Thursday, especially with cloud cover and precipitation filling
in behind the surface front. Highs Thursday may only recover a few
degrees from overnight lows, especially in areas where the surface
front passes during the early morning. Temperatures will be slow to
recover this weekend as the midlevel boundary remains to our
southwest, keeping cooler air entrenched across the region.
Saturday through Tuesday...
A few model solutions break off the southwestern extent of the wave
on Friday, and keep a small disturbance over the Southern High
Plains from Friday night through Saturday. As the southwesterly jet
across the Texas panhandle increases Saturday, the lower pressure
deepens and begins to eject northeastward, possibly bringing
precipitation chances back into our south by early Sunday.
Afterward, another deep trough moves through the central U.S.,
bringing another cold front and additional chances of showers from
Monday morning through Tuesday. Temperatures will have little chance
to rebound back towards normal values early this week before the
next cold front comes through, which indicates mainly below normal
temperatures through the forecast period.
Laflin
&&
.AVIATION...
For the 18Z TAFs...For the rest of the daylight hours VFR conditions
will prevail at the terminals. Errant showers still wafting across
Northwest Missouri do not look likely to effect the KSTJ terminals at
this time, so have avoided mentioning them. Otherwise, focus is on
the arrival of a cold front tonight and the rain that will be
following it. Frontal passage looks to occur after midnight, with
winds become somewhat gusty behind the advancing front. Dry air in
place across the region should limit early morning storms to on-
again-off-again showers, though as we move into the daylight morning
hours rain will likely become more widespread and heavier as
saturation of the boundary layer occurs. Confidence on the ceilings
is rather low, so left them on high the edge of MVFR.
Cutter
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
546 AM CDT Wed Sep 12 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today through Friday...
A band of weak elevated instability ahead of a surface cold front in
central Nebraska and northwest Iowa this morning has fired up a few
very light showers across the northwest corner of the forecast area.
The HRRR indicates these showers may persist just ahead of the
boundary for a few hours before mixing begins to eliminate the
instability, so have added a small chance of very light showers to
the far northwest through late morning. For the rest of the day,
above normal temperatures and breezy south winds can be expected
again, especially across the southwestern corner of the CWA. Surface
low pressure at the base of a deep trough over the northern Rockies
will push eastward into central Kansas today, resulting in the
tighter pressure gradient in our southwest, and could also provide
additional forcing needed to fire up some isolated convection mainly
west of the forecast area late this afternoon. As the main trough
dives to the southeast, the surface cold front will push through
southeast Nebraska and western Iowa, arriving at the northwest
corner of the CWA by 00z. Surface-based instability will build ahead
of the front this afternoon, which may result in isolated convective
initiation along the boundary as it enters the forecast area. Any
isolated development that occurs in central Kansas may also build
eastward during the evening, eventually merging with precipitation
along the cold front. However, surface-based convection will likely
not sustain after sunset, and the bulk of precipitation should occur
behind the surface front as the main wave moves through.
Although showers still look likely through Thursday as the main
trough makes southeastward progress across the CWA, precipitation
chances will decrease as the upper wave weakens and the best energy
transitions further east, towards the Great Lakes region. Have
gradually decreased the chance of precipitation from Thursday
morning through Friday, and also lowered precipitation amounts as
rainfall becomes more scattered. As the wave weakens, it also slows
across the region, so have slowed the southeastward progress of
rainfall chances, especially Thursday night and Friday. Lingering
showers should exit the region altogether by early Friday afternoon.
Temperatures will fall dramatically following cold frontal passage
on Thursday, especially with cloud cover and precipitation filling
in behind the surface front. Highs Thursday may only recover a few
degrees from overnight lows, especially in areas where the surface
front passes during the early morning. Temperatures will be slow to
recover this weekend as the midlevel boundary remains to our
southwest, keeping cooler air entrenched across the region.
Saturday through Tuesday...
A few model solutions break off the southwestern extent of the wave
on Friday, and keep a small disturbance over the Southern High
Plains from Friday night through Saturday. As the southwesterly jet
across the Texas panhandle increases Saturday, the lower pressure
deepens and begins to eject northeastward, possibly bringing
precipitation chances back into our south by early Sunday.
Afterward, another deep trough moves through the central U.S.,
bringing another cold front and additional chances of showers from
Monday morning through Tuesday. Temperatures will have little chance
to rebound back towards normal values early this week before the
next cold front comes through, which indicates mainly below normal
temperatures through the forecast period.
Laflin
&&
.AVIATION...
For the 12Z TAFs, VFR conditions will prevail through much of the
period as southerly winds increase ahead of an advancing cold front.
That cold front is expected to move into the terminals late in the
valid period and and eventually switch winds to the north-northeast.
This will also usher in a good chance for precipitation as well as
lower ceilings, approaching MVFR, in the 06-09Z time frame. The best
chances for rain will come during the day Thursday and it is likely
that the near MVFR conditions will deteriorate as precipitation
increases in intensity and cold air advects into the region aiding a
lowering of cloud cover.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
407 AM CDT Wed Sep 12 2012
.DISCUSSION...
Today through Friday...
A band of weak elevated instability ahead of a surface cold front in
central Nebraska and northwest Iowa this morning has fired up a few
very light showers across the northwest corner of the forecast area.
The HRRR indicates these showers may persist just ahead of the
boundary for a few hours before mixing begins to eliminate the
instability, so have added a small chance of very light showers to
the far northwest through late morning. For the rest of the day,
above normal temperatures and breezy south winds can be expected
again, especially across the southwestern corner of the CWA. Surface
low pressure at the base of a deep trough over the northern Rockies
will push eastward into central Kansas today, resulting in the
tighter pressure gradient in our southwest, and could also provide
additional forcing needed to fire up some isolated convection mainly
west of the forecast area late this afternoon. As the main trough
dives to the southeast, the surface cold front will push through
southeast Nebraska and western Iowa, arriving at the northwest
corner of the CWA by 00z. Surface-based instability will build ahead
of the front this afternoon, which may result in isolated convective
initiation along the boundary as it enters the forecast area. Any
isolated development that occurs in central Kansas may also build
eastward during the evening, eventually merging with precipitation
along the cold front. However, surface-based convection will likely
not sustain after sunset, and the bulk of precipitation should occur
behind the surface front as the main wave moves through.
Although showers still look likely through Thursday as the main
trough makes southeastward progress across the CWA, precipitation
chances will decrease as the upper wave weakens and the best energy
transitions further east, towards the Great Lakes region. Have
gradually decreased the chance of precipitation from Thursday
morning through Friday, and also lowered precipitation amounts as
rainfall becomes more scattered. As the wave weakens, it also slows
across the region, so have slowed the southeastward progress of
rainfall chances, especially Thursday night and Friday. Lingering
showers should exit the region altogether by early Friday afternoon.
Temperatures will fall dramatically following cold frontal passage
on Thursday, especially with cloud cover and precipitation filling
in behind the surface front. Highs Thursday may only recover a few
degrees from overnight lows, especially in areas where the surface
front passes during the early morning. Temperatures will be slow to
recover this weekend as the midlevel boundary remains to our
southwest, keeping cooler air entrenched across the region.
Saturday through Tuesday...
A few model solutions break off the southwestern extent of the wave
on Friday, and keep a small disturbance over the Southern High
Plains from Friday night through Saturday. As the southwesterly jet
across the Texas panhandle increases Saturday, the lower pressure
deepens and begins to eject northeastward, possibly bringing
precipitation chances back into our south by early Sunday.
Afterward, another deep trough moves through the central U.S.,
bringing another cold front and additional chances of showers from
Monday morning through Tuesday. Temperatures will have little chance
to rebound back towards normal values early this week before the
next cold front comes through, which indicates mainly below normal
temperatures through the forecast period.
Laflin
&&
.AVIATION...
For the 06Z TAFs...winds continue to increase around 2000 ft AGL to
near 40 kt. This could cause some very minor LLWS concerns but with
near unidirectional flow near the surface and surface winds around 10
kts, do not expect LLWS to be problematic enough to mention it in the
TAFs. Otherwise expect a gradual increase in mid/high clouds through
the period ahead of a cold front that will approach the TAFs sites
toward 06Z Thurs.
06
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
327 PM CDT WED SEP 12 2012
.DISCUSSION...
UPPER LEVEL TROF SHOULD EXIT THE FCST AREA BY 03Z-06Z WITH 1028 MB
HIGH PRESSURE BUILDING IN OVERNIGHT. RECENT RAINS AND CALM
BOUNDARY LAYER WINDS IN THE WETTER AREAS MIGHT BE SUFFICIENT FOR
PATCHY FOG. LIMITING FACTOR MIGHT BE STRONG SUBSIDENCE WHICH WOULD
NEGATE MOISTURE POOLING.
GIVEN HIGHS IN THE 50S AND 60S THIS AFTERNOON FROST OR FREEZE
POTENTIAL TONIGHT COULD BECOME VERY HIGH IF SKIES CLEAR AS RAPIDLY
AS SOME EARLIER SOLNS OF THE RAP MODEL SHOWED. THE LATEST RAP IS
TRAPPING MOISTURE IN THE BOUNDARY LAYER BENEATH THE SFC HIGH AT
06Z WHICH IS A FOG SIGNATURE. FOR NOW SOME OF THE COOLER GUIDANCE
SUGGESTED PATCHY FROST ACROSS SHERIDAN COUNTY...NOTHING MORE AND
PATCHY FOG IS IN PLACE ACROSS THE WETTER AREAS.
HIGH PRESSURE AND CLEAR SKIES WILL DRIFT ACROSS THE FCST AREA
THURSDAY WITH HIGHS IN THE MID 70S.
FRIDAY THROUGH SUNDAY...ANOTHER SLOWLY EVOLVING NRN PLAINS LOW
PRESSURE SYSTEM WILL DROP INTO WCNTL NEB BY SUNDAY AFTERNOON. THE
TIMING OF THE COLD FRONTAL PASSAGE SUNDAY AFTERNOON SUGGESTS NO
TORCH FEST FOR THE FORECAST AREA AT THIS TIME. SATURDAY MIGHT
ACTUALLY BE THE WARMEST DAY WITH 90F MAYBE ACROSS NORTHWEST
NEB...80S ELSEWHERE. UPPER 70S MODERATING TO THE MID 80S SATURDAY
AND SUNDAY WOULD APPEAR TO BE THE OPERATIVE MODE AT THIS TIME.
WE WOULD EXPECT TO SEE 580DM 10-5MB THICKNESSES FOR HIGHS NEAR OR
ABOVE 90F BUT WE ARE STILL OPERATING IN THE LOW 570S.
MONDAY THROUGH WEDNESDAY...A COLD FRONT WILL SLICE THROUGH THE FCST
AREA SUNDAY AND SUNDAY NIGHT. THERE MAY BE SUFFICIENT RETURN
MOISTURE FOR ISOLD TSTMS SUNDAY NIGHT AND ISOLATED SHRA MONDAY.
TEMPS MONDAY STAY IN THE 60S AS A STRONG CANADIAN HIGH DROPS
THROUGH THE HIGH PLAINS. THE PACIFIC NORTH AMERICAN AMPLIFICATION
WILL BE IN FULL SWING THROUGH WEDNESDAY. MODEL CONSENSUS SUGGESTS
THE RIDGE AXIS LINING UP ACROSS BRITISH COLUMBIA AND THIS WOULD
DIVERT THE COLDEST AIR INTO THE UPPER MIDWEST. THE GEM POSITIONS
THE AXIS FARTHER WEST...IS MORE AMPLIFIED AND TRAPS SOME DYNAMICS
ACROSS WY PRODUCING SNOW.
SFC HIGH PRESSURE WILL MOVE QUICKLY SOUTH AND EAST TUESDAY WITH
LOW PRESSURE AND RETURN FLOW DEVELOPING WEDNESDAY. OTHER THAN THE
RAIN TONIGHT AND ISOLATED CHANCES LATE SUNDAY AND MONDAY THE
FORECAST IS DRY.
&&
.AVIATION...
LIGHT TO MODERATE RAIN SHOWERS ALONG A KONL TO KOGA LINE AT MID
AFTERNOON...WHICH WILL CONTINUE TO SLOWLY TRACK SOUTHEAST DURING THE
LATE AFTERNOON HOURS. -SHRA AND MVFR CIGS WILL BE POSSIBLE AT KLBF
THROUGH 23Z...AFTER THAT TIME GRADUAL CLEARING IS EXPECTED. AT
KVTN...SKIES BEGIN TO CLEAR AS MUCH DRIER AIR MOVES INTO THE AREA
OVERNIGHT. VFR CONDITIONS WILL PREVAIL DURING THE OVERNIGHT AND
THROUGH TOMORROW MORNING.
&&
.FIRE WEATHER...
DID GET RAIN TODAY IN PARTS OF THE FORECAST AREA...BUT MOST
LOCATIONS DID NOT RECEIVE ENOUGH TO WET FUELS TO THE POINT OF BEING
NOT CRITICALLY DRY. ALSO...WHAT WETTING DID OCCUR...WITH SEE THE
OPPORTUNITY TO DRY OUT ON THURSDAY WITH MOSTLY SUNNY SKIES AND HIGHS
IN THE 70S.
A WARMING TREND IS EXPECTED FOR THE WEEKEND...WITH HIGHS IN THE 80S
/AND POSSIBLY A FEW 90S/ FOR SATURDAY AND SUNDAY. DEWPOINTS SHOULD
STAY FAIRLY LOW...IN THE 30S AND LOW 40S THROUGH THIS PERIOD SO
AFTERNOON RELATIVE HUMIDITY WILL DROP TO 15 TO 20 PERCENT ACROSS
PORTIONS OF THE AREA THROUGH FRIDAY...SATURDAY...AND SUNDAY. AM NOT
LOOKING AT PARTICULARLY STRONG WINDS THESE DAYS...BUT COULD GET
GUSTS TO THE 20 TO 25 MPH RANGE EACH DAY.
ANOTHER STRONG SYSTEM THEN LOOKS TO MOVE THROUGH SUNDAY NIGHT...WITH
A WIND SHIFT TO THE NORTH AND MUCH COOLER TEMPERATURES FOR MONDAY.
SUNDAY NIGHT AND MONDAY WILL BE THE NEXT CHANCE FOR RAIN...ALTHOUGH
RAINFALL AMOUNTS DO NOT LOOK TOO IMPRESSIVE AT THIS POINT.
THE WEATHER LOOKS TO BE MARGINAL AT BEST FOR CRITICAL FIRE WEATHER
CONDITIONS OVER THE NEXT WEEK. HOWEVER...WITH THE CONTINUED DRYNESS
OF FUELS...EVEN MARGINAL FIRE WEATHER CONDITIONS CAN...AND HAS
CAUSED EXTREME FIRE BEHAVIOR. THEREFORE...WILL BE CLOSELY MONITORING
THE FORECAST FOR FRIDAY THROUGH SUNDAY FOR THE NEED FOR FIRE WEATHER
HEADLINES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS/MARTIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
101 PM CDT WED SEP 12 2012
.AVIATION...
INITIAL CONCERNS WILL BE RAIN AND SHOWERS AND SOME EMBEDDED
THUNDER AND WINDS. WILL INCLUDE RAIN AND SHOWERS AT ALL THREE TAF
SITES ALONG WITH SOME PATCHY MVFR CIGS. THERE WILL BE
CONVECTION...HOWEVER DUE TO IT/S ISOLATED NATURE WILL NOT MENTION
IN TAFS UNTIL IT IS MORE CERTAIN. THE SURFACE FRONT IS THROUGH
THE SITES...HOWEVER THE UPPER LEVEL DYNAMICS WILL SUPPORT THE
PRECIPITATION BEHIND THE FRONT. NORTHEAST WINDS WILL BE
STRONG...10 TO 20KTS SUSTAINED WITH GUSTS TO AROUND 25KTS. THE
SURFACE WINDS WILL DIMINISH THIS EVENING AT KOFK AND AFTER 06Z AT
KOMA AND KLNK. DECREASING WINDS AND CLOUDS COULD LEAD TO FOG
THURSDAY MORNING. DUE TO THE ACTIVE WEATHER IN THE FIRST
12HRS...WILL NEED TO LOOK AT MORE CLOSELY IN LATER TAF FORECASTS.
&&
.PREV DISCUSSION... /ISSUED 245 AM CDT WED SEP 12 2012/
DISCUSSION...
COLD FRONT EXTENDED FROM NORTHWEST IOWA ACROSS NORTHEAST NEBRASKA
INTO SOUTH CENTRAL NEBRASKA ALONG A KSUX TO KEAR LINE AT 07Z.
SCATTERED SHOWERS AHEAD OF THE FRONT HAVE BECOME MORE NUMEROUS
DURING THE PAST HOUR OVER SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA.
00Z GFS AND 04Z HRRR APPEAR TO BE SIMILAR IN HAVING THE FRONT NEAR
A KOMA TO KHJH LINE BY 12Z...A BIT FASTER THAN THE 00Z NAM.
WILL ADD CHANCE OF SHOWERS AND ISOLATED THUNDER TO AREAS SOUTH OF
THE FRONT THIS MORNING BASED ON RADAR TRENDS AND SHORT RANGE
MODELS. WILL ALSO LIKELY TREND HIGHS TODAY TOWARD THE SOMEWHAT
COOLER GFS GUIDANCE BASED ON FASTER TIMING OF THAT MODEL.
OTHERWISE...STILL LOOKS GOOD FOR WIDESPREAD RAIN ACROSS MUCH OF
THE AREA TONIGHT WITH SYSTEM MOVING OUT OF SOUTHEAST AREAS
THURSDAY MORNING. FAIR AND DRY AFTER THAT WITH COOLER TEMPERATURES
HANGING AROUND FOR A CHANGE.
IN THE EXTENDED...AREA REMAINS UNDER THE INFLUENCE OF COOLER
NORTHWEST FLOW WITH ANOTHER STRONG TROUGH MOVING THROUGH THE
REGION EARLY NEXT WEEK. STILL SOME CHANCE OF SHOWERS WITH COLD
FRONT ON MONDAY WITH LOW POPS MAINTAINED FOR THAT PERIOD. SOME
DIFFERENCES BETWEEN THE GFS AND EURO IN HANDLING THIS FASTER FLOW
SO WILL HAVE TO SEE HOW CONSISTENT FUTURE MODEL RUNS BEHAVE.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
706 AM CDT WED SEP 12 2012
.UPDATE...JUST COMPLETED/SENT A SOMEWHAT SIGNIFICANT UPDATE SOLELY
ADDRESSING THE DAYTIME 12Z-00Z PERIOD...WITH NO CHANGES BEYOND 00Z
MADE FROM THE PREVIOUS MORNING ISSUANCE. STARTING WITH
POPS/WEATHER...AFTER PERUSING THE LATEST GUIDANCE INCLUDING THE
06Z NAM/09Z HRRR/03Z SREF...DECIDED TO SPLIT THE MORNING GRID INTO
TWO 3-HOUR BLOCKS. PRIOR TO 15Z...MOST OF THE CWA SHOULD REMAIN
HIGH AND DRY...AS THE WARM AIR ADVECTION SHOWERS/WEAK STORMS FROM
EARLIER IN THE NIGHT FOCUS MAINLY TO THE EAST...WHILE THE PRIMARY
MID LEVEL FRONTOGENETIC BAND REMAINS WELL TO THE NORTHWEST. THEN
BETWEEN 15Z-18Z...UPPED POPS TO LIKELY 60S-70S ACROSS THE FAR
NORTHWEST CWA AS THE LEADING EDGE OF THIS MID LEVEL SATURATION
SHOULD GET THE MAIN EVENT UNDERWAY. FOR THE AFTERNOON 18Z-00Z
PERIOD LEFT POPS IN A 6-HOUR BLOCK...BUT INCREASED CONSIDERABLY
INTO THE 70 TO NEAR 100 PERCENT RANGE ACROSS ROUGHLY THE NORTHWEST
1/2 OF THE CWA...AS THE LATEST MODELS HAVE SPED UP THE
SOUTHEASTWARD PROGRESSION OF THE RAIN BAND A BIT...INCREASING
CONFIDENCE IN MEASURABLE RAIN BEFORE SUNSET. ON THE OTHER
HAND...MUCH OF THE SOUTHEAST 1/2 OF THE CWA MAY BE LUCKY TO SEE
MUCH OF ANYTHING MEASURABLE THIS AFTERNOON...AND THUS LEFT POPS
PRIMARILY ONLY 20-30 PERCENT...WITH MUCH HIGHER CHANCES OF COURSE
ARRIVING THIS EVENING WHICH IS WELL COVERED IN THE FORECAST.
MOVING ON TO TEMPS...AFTER BLENDING THE 06Z NAM HOURLY TEMPS WITH
THE 00Z CONSALL...ENDED UP SLASHING ACTUAL HIGHS A SOLID 3-6
DEGREES ACROSS MOST OF THE CWA...WITH ONE OF THE BIGGEST CHANGES
NOTED AT PLACES SUCH AS HASTINGS WHICH WAS LOWERED FROM 75 TO 68.
STILL HAVE FAR SOUTHEAST ZONES AROUND BELOIT CLIMBING TO THE MID
80S...BUT EVEN THIS MAY BE A STRETCH IF THE FASTER PROGRESSION OF
THE FRONT EVIDENT IN THE 06Z NAM VERIFIES. FINALLY...INCREASED
WIND SPEEDS A TAD AS WELL...AS NOW EXPECT AN OVERALL GREATER
COVERAGE AND DURATION OF SUSTAINED SPEEDS AT LEAST 20-25 MPH AND
GUSTS TO AROUND 40 MPH. ALTHOUGH A FEW SPOTS COULD BRIEFLY EXCEED
30 MPH SUSTAINED ADVISORY CRITERIA...THIS WOULD LIKELY BE FAR TOO
FLEETING TO JUSTIFY A WIND ADVISORY BUT WILL MENTION NEAR-ADVISORY
SPEEDS IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.PREV DISCUSSION... /ISSUED 556 AM CDT WED SEP 12 2012/
AVIATION...12Z KGRI TAF. A STRONG COLD FRONT HAS PASSED THROUGH
KGRI AND NORTHEAST WINDS WILL QUICKLY GAIN STRENGTH THIS MORNING
AND COULD GUST TO OVER 35 MPH AT TIMES FROM MID MORNING THROUGH
LATE AFTERNOON. MOST OF THE MORNING SHOULD BE DRY WITH INCREASING
CHANCES OF SHOWERS AND THUNDERSTORMS AS WE HEAD THROUGH THE
AFTERNOON. THERE HAVE BEEN A FEW SHOWERS AND ISOLATED
THUNDERSTORMS AROUND KGRI EARLIER THIS MORNING AND WE CAN NOT
TOTALLY RULE OUT A LITTLE RAIN AT THE AIRPORT LATER THIS
MORNING...BUT RAIN WILL BE MOST LIKELY AT KGRI BETWEEN 5 PM AND 11
PM THIS EVENING. RAINFALL AMOUNTS BY THE TIME THE RAIN ENDS LATE
TONIGHT COULD EASILY BE OVER ONE HALF INCH. THERE COULD ALSO BE A
FEW CLAPS OF THUNDER BUT NOTHING STRONG OR SEVERE.
PREV DISCUSSION... /ISSUED 356 AM CDT WED SEP 12 2012/
SHORT TERM...THROUGH FRIDAY NIGHT. CLEARLY THE PARAMOUNT ISSUE
OVER THE NEXT 72 HOURS CONCERNS PRECIP TRENDS DURING THE FIRST 24
HOURS...INCLUDING HOW MUCH RAIN WILL FALL AND WHEN THE MAJORITY OF
IT WILL START/END. ONE THING IS CERTAIN...ALTHOUGH THE MAJORITY OF
THE CWA WILL PROBABLY NOT MEASURE OVER 1 INCH...THIS IS STILL
LOOKING LIKE ONE OF THE MOST WIDESPREAD CHANCES FOR AT LEAST
0.30-0.90 THAT MUCH OF THE AREA HAS SEEN IN AWHILE...ESPECIALLY
NEAR/NORTH OF I-80. SECONDARY CONCERNS INCLUDE A VERY TRICKY TEMP
FORECAST TODAY.
07Z OBJECTIVE SURFACE ANALYSIS AND RADAR IMAGERY PLACES THE WELL-
ADVERTISED COLD FRONT ESSENTIALLY BISECTING THE CWA FROM SW-
NE...WITH THE LEADING EDGE ROUGHLY ALONG A BEAVER CITY-GRAND
ISLAND-COLUMBUS LINE AND SLOWLY BUT STEADILY ADVANCING SOUTHEAST
WITH TIME. THIS FRONT IS ANCHORED TO A 1005MB LOW ALONG THE
SOUTHERN CO/KS BORDER. IN THE WAKE OF THIS FRONT...NORTHERLY WIND
GUSTS HAVE INCREASED WELL INTO THE 25-35 MPH RANGE AT PLACES SUCH
AS ORD AND BROKEN BOW...WHILE AHEAD OF THE FRONT...SOUTHERLY GUSTS
OF AT LEAST 15-25 MPH CONTINUE IN MANY AREAS. THESE BREEZES...IN
TANDEM WITH CONSIDERABLE MID/HIGH CLOUDS HAVE KEPT OVERNIGHT TEMPS
WELL INTO THE 65-75 RANGE THUS FAR CWA-WIDE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA CONFIRMS BROAD WEST-SOUTHWEST
FLOW OVER THE CENTRAL PLAINS...WHILE WELL OFF TO THE NORTH A
POWERFUL VORT MAX OVER NORTHERN MANITOBA ANCHORS A TROUGH AXIS
TRAILING SOUTH INTO THE DAKOTAS/NORTHERN ROCKIES...AND WELL TO THE
SOUTHEAST OF THE CWA A BROAD RIDGE DOMINATES MUCH OF THE SOUTHEAST
CONUS.
STARTING OFF WITH THE EARLY MORNING PERIOD THROUGH SUNRISE...THE
MOST IMMEDIATE ISSUE IS THE RECENT DEVELOPMENT OF ISOLATED TO
SCATTERED SHOWER/FAIRLY WEAK THUNDERSTORM ACTIVITY MAINLY ACROSS
THE FAR NORTHEAST CWA...BUT ALSO STARTING UP OVER SOUTHWEST AND
SOUTHEAST NEB ZONES AS WELL. THIS SOMEWHAT UNEXPECTED PRE-DAWN
FLARE UP WAS NOT WELL CAPTURED BY MOST MODELS...BUT HAS BEEN
SUGGESTED FOR THE LAST SEVERAL HOURLY RUNS OF THE HRRR.
BASICALLY...THIS ACTIVITY SEEMS BEST TIED TO THE WARM AIR/THETA-E
ADVECTION ZONE NEAR AND JUST AHEAD OF THE 850MB COLD FRONT SLICING
INTO THE CWA...AND WITHIN THE AXIS OF A 45-55KT 850MB LOW LEVEL
JET. SPC HOURLY MESO-ANALYSIS ALONG WITH THE 06Z NAM INDICATES
THAT EVEN PEA SIZE HAIL SHOULD BE HARD TO COME BY GIVEN ELEVATED
MUCAPE IN THE 850-700MB LAYER AVERAGING NO MORE THAN 100-200 J/KG.
WILL MAKE A LAST MINUTE DECISION BEFORE FORECAST ISSUANCE
REGARDING HOW TO HANDLE THIS PRE-DAWN ACTIVITY IN THE GRIDS.
TURNING TO THE DAYTIME 12Z-00Z PERIOD...GENERALLY STUCK FAIRLY
CLOSELY TO THE THE THEME OF THE PREVIOUS FORECAST...BUT DUE TO
SOME UNCERTAINTY IN THE TIMING DETAILS OPTED TO NOT SPLIT THE
DAYTIME POP/WEATHER GRIDS INTO MORE THAN TWO 6-HOUR BLOCKS AT THIS
TIME. DESPITE THE EARLY MORNING ACTIVITY ONGOING OUT THERE...WANT
TO EMPHASIZE THAT THE MAJORITY OF THE CWA...ESPECIALLY THE
SOUTHEAST 2/3 WILL LIKELY SEE VERY LITTLE IF ANY MEASURABLE
RAINFALL THROUGH THE DAYTIME HOURS. STARTING WITH THE MORNING
12Z-18Z BLOCK...WILL LEAN TOWARD THE HRRR SUGGESTION THAT MOST OF
THIS PRE-DAWN WARM AIR ADVECTION DRIVEN CONVECTION WILL EXIT EAST
OF THE CWA OR AT LEAST DIMINISH IN COVERAGE BY SUNRISE OR SHORTLY
AFTER. THIS LEAVES THE MAIN FOCUS FOR MORNING PRECIPITATION ACROSS
FAR NORTHWEST PORTIONS OF THE CWA IN CLOSEST PROXIMITY TO THE
SOUTHEAST-ADVANCING MID LEVEL FRONTOGENETIC ZONE ALIGNED WITHIN
THE ENTRANCE REGION OF A 80-100KT 300MB JET STREAK RUNNING FROM
THE DAKOTAS INTO QUEBEC. AT LEAST FOR NOW...KEPT POPS DURING THE
12Z-18Z TIME FRAME BELOW LIKELY TERRITORY...BUT WITH 30-50 POPS
ACROSS THE NORTHWEST HALF TAPERING DOWN TO SLIGHT CHANCE SPRINKLE
WORDING ACROSS THE SOUTHEAST. FOR THE AFTERNOON 18Z-00Z
BLOCK...MAY HAVE NOT GONE HIGH ENOUGH WITH POPS GIVEN LATEST MODEL
TRENDS INCLUDING 06Z NAM...BUT HAVE AT LEAST 40-60 POPS GOING
ACROSS MUCH OF THE NORTHWEST HALF OF THE CWA...AND 70S-90S FAR
NORTH. MOST OF THE RAIN WILL BE TIED TO THE EXACT PLACEMENT OF THE
FAIRLY NARROW FRONTOGENETIC BAND...RESULTING IN A SLOWLY ADVANCING
BUT SHARP CUTOFF FROM STEADY LIGHT/MODERATE RAINFALL TO NOTHING.
KEPT THUNDER WORDING AS ISOLATED THROUGH THE DAY...AS EVEN MODEST
ELEVATED INSTABILITY SHOULD GRADUALLY DECREASE WITH TIME...AND ANY
RISK FOR MARGINALLY STRONG STORMS NEAR THE ACTUAL SURFACE COLD
FRONT DURING THE AFTERNOON/EARLY EVENING SHOULD REMAIN AT LEAST
1-2 COUNTIES SOUTH/SOUTHEAST OF OUR KS ZONES ACROSS THE TOP/ICT
CWA/S. TURNING TO OTHER ELEMENTS...HIGH TEMPS WILL BE VERY TRICKY
DAYS WITH MOST AREAS SEEING STEADY/SLOWLY FALLING TEMPS BEHIND THE
COLD FRONT. TOOK A BEST STAB THAT ENDED UP CLOSE TO PREVIOUS
FORECAST...WITH DAYLIGHT HIGHS RANGING FROM MID 60S FAR NORTHWEST
TO LOW-MID 70S TRI-CITIES AREA AND UPPER 80S FAR SOUTHEAST.
HOWEVER...ACTUAL HOURLY TEMPS ACROSS MUCH OF THE NORTHWEST 1/2 OF
THE CWA THIS AFTERNOON WILL ONLY BE IN THE 50S/60S...SO THE HIGH
TEMP GRID WILL BE A BIT MISLEADING. AS FOR SURFACE WIND
SPEEDS...ANTICIPATE SPEEDS TO AVERAGE AT LEAST 5 MPH BELOW
ADVISORY LEVELS...BUT AS THE FRONT PUSHES IN SHOULD EASILY SEE
SUSTAINED SPEEDS OF 20-25 MPH AND GUSTS UP TO AROUND 35 MPH AND
EVEN AS HIGH AS 40 MPH ON A HIT AND MISS BASIS.
TONIGHT...THIS IS STILL LOOKING LIKE THE MAIN EVENT FOR MOST OF
THE CWA...ESPECIALLY THE SOUTHEAST 2/3...AS THE STRENGTHENING MID
LEVEL FRONTOGENETIC BAND SLIDES SOUTHEAST OVER THE AREA...AND INDUCES
AN INCREASINGLY ORGANIZED BAND OF STEADY LIGHT TO MODERATE AND
POTENTIALLY BRIEFLY HEAVY RAIN. SPLIT THE POP/WEATHER GRIDS INTO
6-HOUR BLOCKS...BUT AT LEAST TOUCHED ALL AREAS SOUTH OF AN ELWOOD-
GRAND ISLAND-FULLERTON LINE WITH 80-90 POPS AT SOME POINT...WITH
LESSER CHANCES TAPERING OFF ACROSS NORTHWEST ZONES AS THE NIGHT
WEARS ON AND PLACES LIKE ORD/GOTHENBURG LIKELY COMPLETELY DONE
WITH PRECIP WELL BEFORE MIDNIGHT. TEMP-WISE...LOWERED LOWS ROUGHLY
3 DEGREES FROM PREVIOUS PER LATEST GUIDANCE...RANGING FROM MID 40S
NORTHWEST TO LOW 50S SOUTHEAST.
THURSDAY...LEFT 20-60 POPS GOING IN THE MORNING BLOCK FOR AREAS
GENERALLY SOUTH OF A PHILLIPSBURG-GENEVA LINE...BUT THE LATEST 06Z
NAM WOULD SUGGEST THAT VIRTUALLY THE ENTIRE CWA MAY BE PRECIP FREE
BY SUNRISE AS IT MOVES THE MID LEVEL BANDING OUT FASTER THAN
PREVIOUSLY ADVERTISED. NO MATTER WHAT...THE ENTIRE CWA WILL MOST
CERTAINLY BE DRY BY THE AFTERNOON HOURS...WITH MOSTLY CLEAR SKIES
INVADING FROM NORTH TO SOUTH AS THE DAY WEARS ON. ASSUMING THAT AT
LEAST A FEW HOURS OF SUNSHINE MATERIALIZES...ESPECIALLY NORTHERN
AREAS SHOULD WARM FAIRLY EFFICIENTLY. NUDGED UP HIGHS 1-3 DEGREES
IN MOST AREAS...WITH MOST NEB ZONES IN THE 71-74 RANGE AND FAR
SOUTHEAST ZONES MORE SO 69-71 WHERE CLOUDS WILL LINGER THE
LONGEST.
BEFORE MOVING ON TO THE DRY LATTER PART OF THE SHORT TERM
PERIOD...A FEW COMMENTS ABOUT RAINFALL AMOUNTS DURING THE NEXT 24-30
HOURS. TAKING LATEST BLEND OF MODEL CONSENSUS ALONG WITH HPC
GUIDANCE...AM NOW ADVERTISING WIDESPREAD QPF RANGING FROM
0.40-0.90 ACROSS THE MAJORITY OF THE CWA...WITH THE BEST POTENTIAL
FOR HIGHER AMOUNTS IN THE 1 INCH TO 1.4 RANGE TARGETING AREAS
SOUTHEAST OF A YORK TO OSBORNE LINE.
THURS NIGHT...COOL HIGH PRESSURE SETTLES INTO THE REGION...AND
ALTHOUGH WET GROUND SHOULD MITIGATE A SHARP TEMP DROP...KEPT LOWS
ON THE CHILLY SIDE AND CLOSE TO PREVIOUS FORECAST WITH MOST AREAS
IN THE 40-45 RANGE...AND EVEN SOME UPPER 30S NOW IN FAVORED COLDER
SPOTS SUCH AS VALLEY/WESTERN DAWSON COUNTIES. UNLESS THINGS TREND
ANOTHER 2-4 DEGREES COLDER...SHOULD BE FREE FROM EARLY SEASON
FROST CONCERNS.
FRIDAY IS LOOKING QUITE PLEASANT OVERALL WITH LIGHT BREEZES AS THE
SURFACE RIDGE AXIS SLOWLY SLIDES EAST...ALONG WITH PLENTY OF
SUNSHINE AS MID LEVEL RIDGING EXTENDS EAST OUT OF THE CENTRAL
ROCKIES. KEPT HIGHS SIMILAR TO PREVIOUS FORECAST WITH MOST AREAS
73-76...ALTHOUGH COULD SEE SOME AREAS A FEW DEGREES HIGHER THAN
THIS PER LATEST 06Z NAM TRENDS.
FRIDAY NIGHT...ANY PRECIP ASSOCIATED WITH A SOUTHERN STREAM WAVE
SHOULD REMAIN NO CLOSER THAN THE KS/OK BORDER AREA...PAVING THE
WAY FOR ANOTHER MAINLY CLEAR NIGHT AS LIGHT BUT STEADY SOUTH WINDS
BECOME ESTABLISHED. CHANGED LOWS LITTLE WITH MAINLY MID-UPPER 40S.
LONG TERM...SATURDAY THROUGH TUESDAY. DRY WEATHER IS EXPECTED OVER
THE WEEKEND AND THEN THERE IS A CHANCE OF THUNDERSTORMS ON MONDAY
AS A COLD FRONT TRACKS ACROSS THE PLAINS. HIGH TEMPERATURES WILL BE
VERY PLEASANT THIS WEEKEND WITH HIGHS ON SATURDAY IN THE MID 70S AND
THEN AROUND 80 FOR MOST AREAS ON SUNDAY. TEMPERATURES WILL COOL
BEHIND THE FRONT ON MONDAY FALLING BACK INTO THE UPPER 60S TO LOWER
70S AND SHOULD REMAIN CLOSE TO THAT ON TUESDAY.
THE UPPER LEVEL PATTERN WILL BE FAIRLY ZONAL OVER THE WEEKEND AND
THEN AN UPPER TROUGH WILL SKIRT THROUGH THE NORTHERN PLAINS ON
MONDAY AND INTO THE GREAT LAKES BY TUESDAY. MOST OF THE DYNAMICS
ASSOCIATED WITH THIS SYSTEM SHOULD BE WELL NORTHEAST OF OUR FORECAST
AREA THUS LIMITING OUR PRECIPITATION CHANCES. CONSALL SEEMS VERY
OVERDONE WITH POPS IN THE 50 TO 60 PERCENT RANGE ON MONDAY. THE NEW
00Z ECMWF CAME IN DRY. OUR PREVIOUS FORECAST WAS ONLY CALLING FOR
SLIGHT POPS AT AROUND 20 PERCENT. WILL INCREASE POPS INTO THE LOW
END CHANCE CATEGORY AT AROUND 30 PERCENT...BUT NOT WILLING TO GO
HIGHER AT THIS POINT IN TIME GIVEN THE NORTHERN TRACK OF THE UPPER
DYNAMICS AND LACK OF SUPPORT IN THE LATEST 00Z ECMWF. THIS SHOULD BE
A QUICK HITTING SYSTEM WITH THE SFC HIGH ALREADY LOCATED EAST OF US
BY TUESDAY ALLOWING FOR A RETURN OF WEAK SOUTHERLY FLOW AND DRY
WEATHER. LATEST MODEL RUNS TONIGHT HAVE BEEN KEEPING THE
INSTABILITY ASSOCIATED WITH THE MONDAY SYSTEM ACROSS KANSAS AND WILL
JUST BE CALLING FOR RAIN SHOWERS OVER MOST NEBRASKA ZONES GIVEN THE
LACK OF INSTABILITY FOR THUNDERSTORMS. WILL CONTINUE TO KEEP A
MENTION OF ISOLATED THUNDERSTORMS SOUTH OF A HEBRON TO ALMA LINE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
611 AM CDT WED SEP 12 2012
.AVIATION...
12Z TAFS FOR KOFK...KOMA AND KLNK.
DECENT FORCING IS EXPECTED TODAY INTO EARLY TONIGHT NEAR AND
BEHIND A COLD FRONT THAT WILL PRESS SOUTHEAST ACROSS THE KLNK AND
KOMA VICINITIES BY MIDDAY. WEAK OUTFLOW COULD BRING VARIABLE
WINDS TO KOMA AND KLNK THIS MORNING BUT IN GENERAL A BRISK NORTH
OR NORTHEAST WIND WAS FORECAST AT TAF SITES BY THIS AFTERNOON.
THE FORCING SHOULD BRING AN INCREASE IN SHOWERS TO THE AREA BUT VERY
DRY LOW LEVEL AIR CREATE UNCERTAINTIES TO HOW LOW VISIBILITIES OR
CEILINGS WILL DROP. THE ISOLATED SHOWERS AND EVEN A RUMBLE OF
THUNDER THIS MORNING WAS NOT EXPECTED TO BE MAIN PRECIP
AREA. THE MAIN OUTBREAK SHOULD SPREAD OR DEVELOP INTO NORTHEAST
NEBRASKA THROUGH THIS AFTERNOON AND THEN SETTLE SOUTHEAST ACROSS
KLNK/KOMA THIS EVENING. MODEL FORECAST SOUNDINGS POINTED AT KLNK
DEVELOPING THE LOWEST CIGS WITH THIS RAIN EVENT AND 12Z TAF FORECAST
REFLECTED THAT. HOWEVER...A PERIOD OF LOWER CIGS/VSBYS ALSO
POSSIBLE AT KOFK AND KOMA LATER TODAY/EARLY TONIGHT AS RAIN AREA
INCREASES. CONDITIONS SHOULD IMPROVE FROM NORTH TO SOUTH TONIGHT.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 245 AM CDT WED SEP 12 2012/
DISCUSSION...
COLD FRONT EXTENDED FROM NORTHWEST IOWA ACROSS NORTHEAST NEBRASKA
INTO SOUTH CENTRAL NEBRASKA ALONG A KSUX TO KEAR LINE AT 07Z.
SCATTERED SHOWERS AHEAD OF THE FRONT HAVE BECOME MORE NUMEROUS
DURING THE PAST HOUR OVER SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA.
00Z GFS AND 04Z HRRR APPEAR TO BE SIMILAR IN HAVING THE FRONT NEAR
A KOMA TO KHJH LINE BY 12Z...A BIT FASTER THAN THE 00Z NAM.
WILL ADD CHANCE OF SHOWERS AND ISOLATED THUNDER TO AREAS SOUTH OF
THE FRONT THIS MORNING BASED ON RADAR TRENDS AND SHORT RANGE
MODELS. WILL ALSO LIKELY TREND HIGHS TODAY TOWARD THE SOMEWHAT
COOLER GFS GUIDANCE BASED ON FASTER TIMING OF THAT MODEL.
OTHERWISE...STILL LOOKS GOOD FOR WIDESPREAD RAIN ACROSS MUCH OF
THE AREA TONIGHT WITH SYSTEM MOVING OUT OF SOUTHEAST AREAS
THURSDAY MORNING. FAIR AND DRY AFTER THAT WITH COOLER TEMPERATURES
HANGING AROUND FOR A CHANGE.
IN THE EXTENDED...AREA REMAINS UNDER THE INFLUENCE OF COOLER
NORTHWEST FLOW WITH ANOTHER STRONG TROUGH MOVING THROUGH THE
REGION EARLY NEXT WEEK. STILL SOME CHANCE OF SHOWERS WITH COLD
FRONT ON MONDAY WITH LOW POPS MAINTAINED FOR THAT PERIOD. SOME
DIFFERENCES BETWEEN THE GFS AND EURO IN HANDLING THIS FASTER FLOW
SO WILL HAVE TO SEE HOW CONSISTENT FUTURE MODEL RUNS BEHAVE.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
556 AM CDT WED SEP 12 2012
.AVIATION...12Z KGRI TAF. A STRONG COLD FRONT HAS PASSED THROUGH
KGRI AND NORTHEAST WINDS WILL QUICKLY GAIN STRENGTH THIS MORNING
AND COULD GUST TO OVER 35 MPH AT TIMES FROM MID MORNING THROUGH
LATE AFTERNOON. MOST OF THE MORNING SHOULD BE DRY WITH INCREASING
CHANCES OF SHOWERS AND THUNDERSTORMS AS WE HEAD THROUGH THE
AFTERNOON. THERE HAVE BEEN A FEW SHOWERS AND ISOLATED
THUNDERSTORMS AROUND KGRI EARLIER THIS MORNING AND WE CAN NOT
TOTALLY RULE OUT A LITTLE RAIN AT THE AIRPORT LATER THIS
MORNING...BUT RAIN WILL BE MOST LIKELY AT KGRI BETWEEN 5 PM AND 11
PM THIS EVENING. RAINFALL AMOUNTS BY THE TIME THE RAIN ENDS LATE
TONIGHT COULD EASILY BE OVER ONE HALF INCH. THERE COULD ALSO BE A
FEW CLAPS OF THUNDER BUT NOTHING STRONG OR SEVERE.
&&
.PREV DISCUSSION... /ISSUED 356 AM CDT WED SEP 12 2012/
SHORT TERM...THROUGH FRIDAY NIGHT. CLEARLY THE PARAMOUNT ISSUE
OVER THE NEXT 72 HOURS CONCERNS PRECIP TRENDS DURING THE FIRST 24
HOURS...INCLUDING HOW MUCH RAIN WILL FALL AND WHEN THE MAJORITY OF
IT WILL START/END. ONE THING IS CERTAIN...ALTHOUGH THE MAJORITY OF
THE CWA WILL PROBABLY NOT MEASURE OVER 1 INCH...THIS IS STILL
LOOKING LIKE ONE OF THE MOST WIDESPREAD CHANCES FOR AT LEAST
0.30-0.90 THAT MUCH OF THE AREA HAS SEEN IN AWHILE...ESPECIALLY
NEAR/NORTH OF I-80. SECONDARY CONCERNS INCLUDE A VERY TRICKY TEMP
FORECAST TODAY.
07Z OBJECTIVE SURFACE ANALYSIS AND RADAR IMAGERY PLACES THE WELL-
ADVERTISED COLD FRONT ESSENTIALLY BISECTING THE CWA FROM SW-
NE...WITH THE LEADING EDGE ROUGHLY ALONG A BEAVER CITY-GRAND
ISLAND-COLUMBUS LINE AND SLOWLY BUT STEADILY ADVANCING SOUTHEAST
WITH TIME. THIS FRONT IS ANCHORED TO A 1005MB LOW ALONG THE
SOUTHERN CO/KS BORDER. IN THE WAKE OF THIS FRONT...NORTHERLY WIND
GUSTS HAVE INCREASED WELL INTO THE 25-35 MPH RANGE AT PLACES SUCH
AS ORD AND BROKEN BOW...WHILE AHEAD OF THE FRONT...SOUTHERLY GUSTS
OF AT LEAST 15-25 MPH CONTINUE IN MANY AREAS. THESE BREEZES...IN
TANDEM WITH CONSIDERABLE MID/HIGH CLOUDS HAVE KEPT OVERNIGHT TEMPS
WELL INTO THE 65-75 RANGE THUS FAR CWA-WIDE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA CONFIRMS BROAD WEST-SOUTHWEST
FLOW OVER THE CENTRAL PLAINS...WHILE WELL OFF TO THE NORTH A
POWERFUL VORT MAX OVER NORTHERN MANITOBA ANCHORS A TROUGH AXIS
TRAILING SOUTH INTO THE DAKOTAS/NORTHERN ROCKIES...AND WELL TO THE
SOUTHEAST OF THE CWA A BROAD RIDGE DOMINATES MUCH OF THE SOUTHEAST
CONUS.
STARTING OFF WITH THE EARLY MORNING PERIOD THROUGH SUNRISE...THE
MOST IMMEDIATE ISSUE IS THE RECENT DEVELOPMENT OF ISOLATED TO
SCATTERED SHOWER/FAIRLY WEAK THUNDERSTORM ACTIVITY MAINLY ACROSS
THE FAR NORTHEAST CWA...BUT ALSO STARTING UP OVER SOUTHWEST AND
SOUTHEAST NEB ZONES AS WELL. THIS SOMEWHAT UNEXPECTED PRE-DAWN
FLARE UP WAS NOT WELL CAPTURED BY MOST MODELS...BUT HAS BEEN
SUGGESTED FOR THE LAST SEVERAL HOURLY RUNS OF THE HRRR.
BASICALLY...THIS ACTIVITY SEEMS BEST TIED TO THE WARM AIR/THETA-E
ADVECTION ZONE NEAR AND JUST AHEAD OF THE 850MB COLD FRONT SLICING
INTO THE CWA...AND WITHIN THE AXIS OF A 45-55KT 850MB LOW LEVEL
JET. SPC HOURLY MESO- ANALYSIS ALONG WITH THE 06Z NAM INDICATES
THAT EVEN PEA SIZE HAIL SHOULD BE HARD TO COME BY GIVEN ELEVATED
MUCAPE IN THE 850-700MB LAYER AVERAGING NO MORE THAN 100-200 J/KG.
WILL MAKE A LAST MINUTE DECISION BEFORE FORECAST ISSUANCE
REGARDING HOW TO HANDLE THIS PRE-DAWN ACTIVITY IN THE GRIDS.
TURNING TO THE DAYTIME 12Z-00Z PERIOD...GENERALLY STUCK FAIRLY
CLOSELY TO THE THE THEME OF THE PREVIOUS FORECAST...BUT DUE TO
SOME UNCERTAINTY IN THE TIMING DETAILS OPTED TO NOT SPLIT THE
DAYTIME POP/WEATHER GRIDS INTO MORE THAN TWO 6-HOUR BLOCKS AT THIS
TIME. DESPITE THE EARLY MORNING ACTIVITY ONGOING OUT THERE...WANT
TO EMPHASIZE THAT THE MAJORITY OF THE CWA...ESPECIALLY THE
SOUTHEAST 2/3 WILL LIKELY SEE VERY LITTLE IF ANY MEASURABLE
RAINFALL THROUGH THE DAYTIME HOURS. STARTING WITH THE MORNING
12Z-18Z BLOCK...WILL LEAN TOWARD THE HRRR SUGGESTION THAT MOST OF
THIS PRE-DAWN WARM AIR ADVECTION DRIVEN CONVECTION WILL EXIT EAST
OF THE CWA OR AT LEAST DIMINISH IN COVERAGE BY SUNRISE OR SHORTLY
AFTER. THIS LEAVES THE MAIN FOCUS FOR MORNING PRECIPITATION ACROSS
FAR NORTHWEST PORTIONS OF THE CWA IN CLOSEST PROXIMITY TO THE
SOUTHEAST-ADVANCING MID LEVEL FRONTOGENETIC ZONE ALIGNED WITHIN
THE ENTRANCE REGION OF A 80-100KT 300MB JET STREAK RUNNING FROM
THE DAKOTAS INTO QUEBEC. AT LEAST FOR NOW...KEPT POPS DURING THE
12Z-18Z TIME FRAME BELOW LIKELY TERRITORY...BUT WITH 30-50 POPS
ACROSS THE NORTHWEST HALF TAPERING DOWN TO SLIGHT CHANCE SPRINKLE
WORDING ACROSS THE SOUTHEAST. FOR THE AFTERNOON 18Z-00Z
BLOCK...MAY HAVE NOT GONE HIGH ENOUGH WITH POPS GIVEN LATEST MODEL
TRENDS INCLUDING 06Z NAM...BUT HAVE AT LEAST 40-60 POPS GOING
ACROSS MUCH OF THE NORTHWEST HALF OF THE CWA...AND 70S-90S FAR
NORTH. MOST OF THE RAIN WILL BE TIED TO THE EXACT PLACEMENT OF THE
FAIRLY NARROW FRONTOGENETIC BAND...RESULTING IN A SLOWLY ADVANCING
BUT SHARP CUTOFF FROM STEADY LIGHT/MODERATE RAINFALL TO NOTHING.
KEPT THUNDER WORDING AS ISOLATED THROUGH THE DAY...AS EVEN MODEST
ELEVATED INSTABILITY SHOULD GRADUALLY DECREASE WITH TIME...AND ANY
RISK FOR MARGINALLY STRONG STORMS NEAR THE ACTUAL SURFACE COLD
FRONT DURING THE AFTERNOON/EARLY EVENING SHOULD REMAIN AT LEAST
1-2 COUNTIES SOUTH/SOUTHEAST OF OUR KS ZONES ACROSS THE TOP/ICT
CWA/S. TURNING TO OTHER ELEMENTS...HIGH TEMPS WILL BE VERY TRICKY
DAYS WITH MOST AREAS SEEING STEADY/SLOWLY FALLING TEMPS BEHIND THE
COLD FRONT. TOOK A BEST STAB THAT ENDED UP CLOSE TO PREVIOUS
FORECAST...WITH DAYLIGHT HIGHS RANGING FROM MID 60S FAR NORTHWEST
TO LOW-MID 70S TRI-CITIES AREA AND UPPER 80S FAR SOUTHEAST.
HOWEVER...ACTUAL HOURLY TEMPS ACROSS MUCH OF THE NORTHWEST 1/2 OF
THE CWA THIS AFTERNOON WILL ONLY BE IN THE 50S/60S...SO THE HIGH
TEMP GRID WILL BE A BIT MISLEADING. AS FOR SURFACE WIND
SPEEDS...ANTICIPATE SPEEDS TO AVERAGE AT LEAST 5 MPH BELOW
ADVISORY LEVELS...BUT AS THE FRONT PUSHES IN SHOULD EASILY SEE
SUSTAINED SPEEDS OF 20-25 MPH AND GUSTS UP TO AROUND 35 MPH AND
EVEN AS HIGH AS 40 MPH ON A HIT AND MISS BASIS.
TONIGHT...THIS IS STILL LOOKING LIKE THE MAIN EVENT FOR MOST OF
THE CWA...ESPECIALLY THE SOUTHEAST 2/3...AS THE STRENGTHENING MID
LEVEL FRONTOGENETIC BAND SLIDES SOUTHEAST OVER THE AREA...AND INDUCES
AN INCREASINGLY ORGANIZED BAND OF STEADY LIGHT TO MODERATE AND
POTENTIALLY BRIEFLY HEAVY RAIN. SPLIT THE POP/WEATHER GRIDS INTO
6-HOUR BLOCKS...BUT AT LEAST TOUCHED ALL AREAS SOUTH OF AN ELWOOD-
GRAND ISLAND-FULLERTON LINE WITH 80-90 POPS AT SOME POINT...WITH
LESSER CHANCES TAPERING OFF ACROSS NORTHWEST ZONES AS THE NIGHT
WEARS ON AND PLACES LIKE ORD/GOTHENBURG LIKELY COMPLETELY DONE
WITH PRECIP WELL BEFORE MIDNIGHT. TEMP-WISE...LOWERED LOWS ROUGHLY
3 DEGREES FROM PREVIOUS PER LATEST GUIDANCE...RANGING FROM MID 40S
NORTHWEST TO LOW 50S SOUTHEAST.
THURSDAY...LEFT 20-60 POPS GOING IN THE MORNING BLOCK FOR AREAS
GENERALLY SOUTH OF A PHILLIPSBURG-GENEVA LINE...BUT THE LATEST 06Z
NAM WOULD SUGGEST THAT VIRTUALLY THE ENTIRE CWA MAY BE PRECIP FREE
BY SUNRISE AS IT MOVES THE MID LEVEL BANDING OUT FASTER THAN
PREVIOUSLY ADVERTISED. NO MATTER WHAT...THE ENTIRE CWA WILL MOST
CERTAINLY BE DRY BY THE AFTERNOON HOURS...WITH MOSTLY CLEAR SKIES
INVADING FROM NORTH TO SOUTH AS THE DAY WEARS ON. ASSUMING THAT AT
LEAST A FEW HOURS OF SUNSHINE MATERIALIZES...ESPECIALLY NORTHERN
AREAS SHOULD WARM FAIRLY EFFICIENTLY. NUDGED UP HIGHS 1-3 DEGREES
IN MOST AREAS...WITH MOST NEB ZONES IN THE 71-74 RANGE AND FAR
SOUTHEAST ZONES MORE SO 69-71 WHERE CLOUDS WILL LINGER THE
LONGEST.
BEFORE MOVING ON TO THE DRY LATTER PART OF THE SHORT TERM
PERIOD...A FEW COMMENTS ABOUT RAINFALL AMOUNTS DURING THE NEXT 24-30
HOURS. TAKING LATEST BLEND OF MODEL CONSENSUS ALONG WITH HPC
GUIDANCE...AM NOW ADVERTISING WIDESPREAD QPF RANGING FROM
0.40-0.90 ACROSS THE MAJORITY OF THE CWA...WITH THE BEST POTENTIAL
FOR HIGHER AMOUNTS IN THE 1 INCH TO 1.4 RANGE TARGETING AREAS
SOUTHEAST OF A YORK TO OSBORNE LINE.
THURS NIGHT...COOL HIGH PRESSURE SETTLES INTO THE REGION...AND
ALTHOUGH WET GROUND SHOULD MITIGATE A SHARP TEMP DROP...KEPT LOWS
ON THE CHILLY SIDE AND CLOSE TO PREVIOUS FORECAST WITH MOST AREAS
IN THE 40-45 RANGE...AND EVEN SOME UPPER 30S NOW IN FAVORED COLDER
SPOTS SUCH AS VALLEY/WESTERN DAWSON COUNTIES. UNLESS THINGS TREND
ANOTHER 2-4 DEGREES COLDER...SHOULD BE FREE FROM EARLY SEASON
FROST CONCERNS.
FRIDAY IS LOOKING QUITE PLEASANT OVERALL WITH LIGHT BREEZES AS THE
SURFACE RIDGE AXIS SLOWLY SLIDES EAST...ALONG WITH PLENTY OF
SUNSHINE AS MID LEVEL RIDGING EXTENDS EAST OUT OF THE CENTRAL
ROCKIES. KEPT HIGHS SIMILAR TO PREVIOUS FORECAST WITH MOST AREAS
73-76...ALTHOUGH COULD SEE SOME AREAS A FEW DEGREES HIGHER THAN
THIS PER LATEST 06Z NAM TRENDS.
FRIDAY NIGHT...ANY PRECIP ASSOCIATED WITH A SOUTHERN STREAM WAVE
SHOULD REMAIN NO CLOSER THAN THE KS/OK BORDER AREA...PAVING THE
WAY FOR ANOTHER MAINLY CLEAR NIGHT AS LIGHT BUT STEADY SOUTH WINDS
BECOME ESTABLISHED. CHANGED LOWS LITTLE WITH MAINLY MID-UPPER 40S.
LONG TERM...SATURDAY THROUGH TUESDAY. DRY WEATHER IS EXPECTED OVER
THE WEEKEND AND THEN THERE IS A CHANCE OF THUNDERSTORMS ON MONDAY
AS A COLD FRONT TRACKS ACROSS THE PLAINS. HIGH TEMPERATURES WILL BE
VERY PLEASANT THIS WEEKEND WITH HIGHS ON SATURDAY IN THE MID 70S AND
THEN AROUND 80 FOR MOST AREAS ON SUNDAY. TEMPERATURES WILL COOL
BEHIND THE FRONT ON MONDAY FALLING BACK INTO THE UPPER 60S TO LOWER
70S AND SHOULD REMAIN CLOSE TO THAT ON TUESDAY.
THE UPPER LEVEL PATTERN WILL BE FAIRLY ZONAL OVER THE WEEKEND AND
THEN AN UPPER TROUGH WILL SKIRT THROUGH THE NORTHERN PLAINS ON
MONDAY AND INTO THE GREAT LAKES BY TUESDAY. MOST OF THE DYNAMICS
ASSOCIATED WITH THIS SYSTEM SHOULD BE WELL NORTHEAST OF OUR FORECAST
AREA THUS LIMITING OUR PRECIPITATION CHANCES. CONSALL SEEMS VERY
OVERDONE WITH POPS IN THE 50 TO 60 PERCENT RANGE ON MONDAY. THE NEW
00Z ECMWF CAME IN DRY. OUR PREVIOUS FORECAST WAS ONLY CALLING FOR
SLIGHT POPS AT AROUND 20 PERCENT. WILL INCREASE POPS INTO THE LOW
END CHANCE CATEGORY AT AROUND 30 PERCENT...BUT NOT WILLING TO GO
HIGHER AT THIS POINT IN TIME GIVEN THE NORTHERN TRACK OF THE UPPER
DYNAMICS AND LACK OF SUPPORT IN THE LATEST 00Z ECMWF. THIS SHOULD BE
A QUICK HITTING SYSTEM WITH THE SFC HIGH ALREADY LOCATED EAST OF US
BY TUESDAY ALLOWING FOR A RETURN OF WEAK SOUTHERLY FLOW AND DRY
WEATHER. LATEST MODEL RUNS TONIGHT HAVE BEEN KEEPING THE
INSTABILITY ASSOCIATED WITH THE MONDAY SYSTEM ACROSS KANSAS AND WILL
JUST BE CALLING FOR RAIN SHOWERS OVER MOST NEBRASKA ZONES GIVEN THE
LACK OF INSTABILITY FOR THUNDERSTORMS. WILL CONTINUE TO KEEP A
MENTION OF ISOLATED THUNDERSTORMS SOUTH OF A HEBRON TO ALMA LINE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
356 AM CDT WED SEP 12 2012
.SHORT TERM...THROUGH FRIDAY NIGHT. CLEARLY THE PARAMOUNT ISSUE
OVER THE NEXT 72 HOURS CONCERNS PRECIP TRENDS DURING THE FIRST 24
HOURS...INCLUDING HOW MUCH RAIN WILL FALL AND WHEN THE MAJORITY OF
IT WILL START/END. ONE THING IS CERTAIN...ALTHOUGH THE MAJORITY OF
THE CWA WILL PROBABLY NOT MEASURE OVER 1 INCH...THIS IS STILL
LOOKING LIKE ONE OF THE MOST WIDESPREAD CHANCES FOR AT LEAST
0.30-0.90 THAT MUCH OF THE AREA HAS SEEN IN AWHILE...ESPECIALLY
NEAR/NORTH OF I-80. SECONDARY CONCERNS INCLUDE A VERY TRICKY TEMP
FORECAST TODAY.
07Z OBJECTIVE SURFACE ANALYSIS AND RADAR IMAGERY PLACES THE WELL-
ADVERTISED COLD FRONT ESSENTIALLY BISECTING THE CWA FROM SW-
NE...WITH THE LEADING EDGE ROUGHLY ALONG A BEAVER CITY-GRAND
ISLAND-COLUMBUS LINE AND SLOWLY BUT STEADILY ADVANCING SOUTHEAST
WITH TIME. THIS FRONT IS ANCHORED TO A 1005MB LOW ALONG THE
SOUTHERN CO/KS BORDER. IN THE WAKE OF THIS FRONT...NORTHERLY WIND
GUSTS HAVE INCREASED WELL INTO THE 25-35 MPH RANGE AT PLACES SUCH
AS ORD AND BROKEN BOW...WHILE AHEAD OF THE FRONT...SOUTHERLY GUSTS
OF AT LEAST 15-25 MPH CONTINUE IN MANY AREAS. THESE BREEZES...IN
TANDEM WITH CONSIDERABLE MID/HIGH CLOUDS HAVE KEPT OVERNIGHT TEMPS
WELL INTO THE 65-75 RANGE THUS FAR CWA-WIDE. ALOFT...WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA CONFIRMS BROAD WEST-SOUTHWEST
FLOW OVER THE CENTRAL PLAINS...WHILE WELL OFF TO THE NORTH A
POWERFUL VORT MAX OVER NORTHERN MANITOBA ANCHORS A TROUGH AXIS
TRAILING SOUTH INTO THE DAKOTAS/NORTHERN ROCKIES...AND WELL TO THE
SOUTHEAST OF THE CWA A BROAD RIDGE DOMINATES MUCH OF THE SOUTHEAST
CONUS.
STARTING OFF WITH THE EARLY MORNING PERIOD THROUGH SUNRISE...THE
MOST IMMEDIATE ISSUE IS THE RECENT DEVELOPMENT OF ISOLATED TO
SCATTERED SHOWER/FAIRLY WEAK THUNDERSTORM ACTIVITY MAINLY ACROSS
THE FAR NORTHEAST CWA...BUT ALSO STARTING UP OVER SOUTHWEST AND
SOUTHEAST NEB ZONES AS WELL. THIS SOMEWHAT UNEXPECTED PRE-DAWN
FLARE UP WAS NOT WELL CAPTURED BY MOST MODELS...BUT HAS BEEN
SUGGESTED FOR THE LAST SEVERAL HOURLY RUNS OF THE HRRR.
BASICALLY...THIS ACTIVITY SEEMS BEST TIED TO THE WARM AIR/THETA-E
ADVECTION ZONE NEAR AND JUST AHEAD OF THE 850MB COLD FRONT SLICING
INTO THE CWA...AND WITHIN THE AXIS OF A 45-55KT 850MB LOW LEVEL
JET. SPC HOURLY MESO- ANALYSIS ALONG WITH THE 06Z NAM INDICATES
THAT EVEN PEA SIZE HAIL SHOULD BE HARD TO COME BY GIVEN ELEVATED
MUCAPE IN THE 850-700MB LAYER AVERAGING NO MORE THAN 100-200 J/KG.
WILL MAKE A LAST MINUTE DECISION BEFORE FORECAST ISSUANCE
REGARDING HOW TO HANDLE THIS PRE-DAWN ACTIVITY IN THE GRIDS.
TURNING TO THE DAYTIME 12Z-00Z PERIOD...GENERALLY STUCK FAIRLY
CLOSELY TO THE THE THEME OF THE PREVIOUS FORECAST...BUT DUE TO
SOME UNCERTAINTY IN THE TIMING DETAILS OPTED TO NOT SPLIT THE
DAYTIME POP/WEATHER GRIDS INTO MORE THAN TWO 6-HOUR BLOCKS AT THIS
TIME. DESPITE THE EARLY MORNING ACTIVITY ONGOING OUT THERE...WANT
TO EMPHASIZE THAT THE MAJORITY OF THE CWA...ESPECIALLY THE
SOUTHEAST 2/3 WILL LIKELY SEE VERY LITTLE IF ANY MEASURABLE
RAINFALL THROUGH THE DAYTIME HOURS. STARTING WITH THE MORNING
12Z-18Z BLOCK...WILL LEAN TOWARD THE HRRR SUGGESTION THAT MOST OF
THIS PRE-DAWN WARM AIR ADVECTION DRIVEN CONVECTION WILL EXIT EAST
OF THE CWA OR AT LEAST DIMINISH IN COVERAGE BY SUNRISE OR SHORTLY
AFTER. THIS LEAVES THE MAIN FOCUS FOR MORNING PRECIPITATION ACROSS
FAR NORTHWEST PORTIONS OF THE CWA IN CLOSEST PROXIMITY TO THE
SOUTHEAST-ADVANCING MID LEVEL FRONTOGENETIC ZONE ALIGNED WITHIN
THE ENTRANCE REGION OF A 80-100KT 300MB JET STREAK RUNNING FROM
THE DAKOTAS INTO QUEBEC. AT LEAST FOR NOW...KEPT POPS DURING THE
12Z-18Z TIME FRAME BELOW LIKELY TERRITORY...BUT WITH 30-50 POPS
ACROSS THE NORTHWEST HALF TAPERING DOWN TO SLIGHT CHANCE SPRINKLE
WORDING ACROSS THE SOUTHEAST. FOR THE AFTERNOON 18Z-00Z
BLOCK...MAY HAVE NOT GONE HIGH ENOUGH WITH POPS GIVEN LATEST MODEL
TRENDS INCLUDING 06Z NAM...BUT HAVE AT LEAST 40-60 POPS GOING
ACROSS MUCH OF THE NORTHWEST HALF OF THE CWA...AND 70S-90S FAR
NORTH. MOST OF THE RAIN WILL BE TIED TO THE EXACT PLACEMENT OF THE
FAIRLY NARROW FRONTOGENETIC BAND...RESULTING IN A SLOWLY ADVANCING
BUT SHARP CUTOFF FROM STEADY LIGHT/MODERATE RAINFALL TO NOTHING.
KEPT THUNDER WORDING AS ISOLATED THROUGH THE DAY...AS EVEN MODEST
ELEVATED INSTABILITY SHOULD GRADUALLY DECREASE WITH TIME...AND ANY
RISK FOR MARGINALLY STRONG STORMS NEAR THE ACTUAL SURFACE COLD
FRONT DURING THE AFTERNOON/EARLY EVENING SHOULD REMAIN AT LEAST
1-2 COUNTIES SOUTH/SOUTHEAST OF OUR KS ZONES ACROSS THE TOP/ICT
CWA/S. TURNING TO OTHER ELEMENTS...HIGH TEMPS WILL BE VERY TRICKY
DAYS WITH MOST AREAS SEEING STEADY/SLOWLY FALLING TEMPS BEHIND THE
COLD FRONT. TOOK A BEST STAB THAT ENDED UP CLOSE TO PREVIOUS
FORECAST...WITH DAYLIGHT HIGHS RANGING FROM MID 60S FAR NORTHWEST
TO LOW-MID 70S TRI-CITIES AREA AND UPPER 80S FAR SOUTHEAST.
HOWEVER...ACTUAL HOURLY TEMPS ACROSS MUCH OF THE NORTHWEST 1/2 OF
THE CWA THIS AFTERNOON WILL ONLY BE IN THE 50S/60S...SO THE HIGH
TEMP GRID WILL BE A BIT MISLEADING. AS FOR SURFACE WIND
SPEEDS...ANTICIPATE SPEEDS TO AVERAGE AT LEAST 5 MPH BELOW
ADVISORY LEVELS...BUT AS THE FRONT PUSHES IN SHOULD EASILY SEE
SUSTAINED SPEEDS OF 20-25 MPH AND GUSTS UP TO AROUND 35 MPH AND
EVEN AS HIGH AS 40 MPH ON A HIT AND MISS BASIS.
TONIGHT...THIS IS STILL LOOKING LIKE THE MAIN EVENT FOR MOST OF
THE CWA...ESPECIALLY THE SOUTHEAST 2/3...AS THE STRENGTHENING MID
LEVEL FRONTOGENETIC BAND SLIDES SOUTHEAST OVER THE AREA...AND INDUCES
AN INCREASINGLY ORGANIZED BAND OF STEADY LIGHT TO MODERATE AND
POTENTIALLY BRIEFLY HEAVY RAIN. SPLIT THE POP/WEATHER GRIDS INTO
6-HOUR BLOCKS...BUT AT LEAST TOUCHED ALL AREAS SOUTH OF AN ELWOOD-
GRAND ISLAND-FULLERTON LINE WITH 80-90 POPS AT SOME POINT...WITH
LESSER CHANCES TAPERING OFF ACROSS NORTHWEST ZONES AS THE NIGHT
WEARS ON AND PLACES LIKE ORD/GOTHENBURG LIKELY COMPLETELY DONE
WITH PRECIP WELL BEFORE MIDNIGHT. TEMP-WISE...LOWERED LOWS ROUGHLY
3 DEGREES FROM PREVIOUS PER LATEST GUIDANCE...RANGING FROM MID 40S
NORTHWEST TO LOW 50S SOUTHEAST.
THURSDAY...LEFT 20-60 POPS GOING IN THE MORNING BLOCK FOR AREAS
GENERALLY SOUTH OF A PHILLIPSBURG-GENEVA LINE...BUT THE LATEST 06Z
NAM WOULD SUGGEST THAT VIRTUALLY THE ENTIRE CWA MAY BE PRECIP FREE
BY SUNRISE AS IT MOVES THE MID LEVEL BANDING OUT FASTER THAN
PREVIOUSLY ADVERTISED. NO MATTER WHAT...THE ENTIRE CWA WILL MOST
CERTAINLY BE DRY BY THE AFTERNOON HOURS...WITH MOSTLY CLEAR SKIES
INVADING FROM NORTH TO SOUTH AS THE DAY WEARS ON. ASSUMING THAT AT
LEAST A FEW HOURS OF SUNSHINE MATERIALIZES...ESPECIALLY NORTHERN
AREAS SHOULD WARM FAIRLY EFFICIENTLY. NUDGED UP HIGHS 1-3 DEGREES
IN MOST AREAS...WITH MOST NEB ZONES IN THE 71-74 RANGE AND FAR
SOUTHEAST ZONES MORE SO 69-71 WHERE CLOUDS WILL LINGER THE
LONGEST.
BEFORE MOVING ON TO THE DRY LATTER PART OF THE SHORT TERM
PERIOD...A FEW COMMENTS ABOUT RAINFALL AMOUNTS DURING THE NEXT 24-30
HOURS. TAKING LATEST BLEND OF MODEL CONSENSUS ALONG WITH HPC
GUIDANCE...AM NOW ADVERTISING WIDESPREAD QPF RANGING FROM
0.40-0.90 ACROSS THE MAJORITY OF THE CWA...WITH THE BEST POTENTIAL
FOR HIGHER AMOUNTS IN THE 1 INCH TO 1.4 RANGE TARGETING AREAS
SOUTHEAST OF A YORK TO OSBORNE LINE.
THURS NIGHT...COOL HIGH PRESSURE SETTLES INTO THE REGION...AND
ALTHOUGH WET GROUND SHOULD MITIGATE A SHARP TEMP DROP...KEPT LOWS
ON THE CHILLY SIDE AND CLOSE TO PREVIOUS FORECAST WITH MOST AREAS
IN THE 40-45 RANGE...AND EVEN SOME UPPER 30S NOW IN FAVORED COLDER
SPOTS SUCH AS VALLEY/WESTERN DAWSON COUNTIES. UNLESS THINGS TREND
ANOTHER 2-4 DEGREES COLDER...SHOULD BE FREE FROM EARLY SEASON
FROST CONCERNS.
FRIDAY IS LOOKING QUITE PLEASANT OVERALL WITH LIGHT BREEZES AS THE
SURFACE RIDGE AXIS SLOWLY SLIDES EAST...ALONG WITH PLENTY OF
SUNSHINE AS MID LEVEL RIDGING EXTENDS EAST OUT OF THE CENTRAL
ROCKIES. KEPT HIGHS SIMILAR TO PREVIOUS FORECAST WITH MOST AREAS
73-76...ALTHOUGH COULD SEE SOME AREAS A FEW DEGREES HIGHER THAN
THIS PER LATEST 06Z NAM TRENDS.
FRIDAY NIGHT...ANY PRECIP ASSOCIATED WITH A SOUTHERN STREAM WAVE
SHOULD REMAIN NO CLOSER THAN THE KS/OK BORDER AREA...PAVING THE
WAY FOR ANOTHER MAINLY CLEAR NIGHT AS LIGHT BUT STEADY SOUTH WINDS
BECOME ESTABLISHED. CHANGED LOWS LITTLE WITH MAINLY MID-UPPER 40S.
.LONG TERM...SATURDAY THROUGH TUESDAY. DRY WEATHER IS EXPECTED OVER
THE WEEKEND AND THEN THERE IS A CHANCE OF THUNDERSTORMS ON MONDAY
AS A COLD FRONT TRACKS ACROSS THE PLAINS. HIGH TEMPERATURES WILL BE
VERY PLEASANT THIS WEEKEND WITH HIGHS ON SATURDAY IN THE MID 70S AND
THEN AROUND 80 FOR MOST AREAS ON SUNDAY. TEMPERATURES WILL COOL
BEHIND THE FRONT ON MONDAY FALLING BACK INTO THE UPPER 60S TO LOWER
70S AND SHOULD REMAIN CLOSE TO THAT ON TUESDAY.
THE UPPER LEVEL PATTERN WILL BE FAIRLY ZONAL OVER THE WEEKEND AND
THEN AN UPPER TROUGH WILL SKIRT THROUGH THE NORTHERN PLAINS ON
MONDAY AND INTO THE GREAT LAKES BY TUESDAY. MOST OF THE DYNAMICS
ASSOCIATED WITH THIS SYSTEM SHOULD BE WELL NORTHEAST OF OUR FORECAST
AREA THUS LIMITING OUR PRECIPITATION CHANCES. CONSALL SEEMS VERY
OVERDONE WITH POPS IN THE 50 TO 60 PERCENT RANGE ON MONDAY. THE NEW
00Z ECMWF CAME IN DRY. OUR PREVIOUS FORECAST WAS ONLY CALLING FOR
SLIGHT POPS AT AROUND 20 PERCENT. WILL INCREASE POPS INTO THE LOW
END CHANCE CATEGORY AT AROUND 30 PERCENT...BUT NOT WILLING TO GO
HIGHER AT THIS POINT IN TIME GIVEN THE NORTHERN TRACK OF THE UPPER
DYNAMICS AND LACK OF SUPPORT IN THE LATEST 00Z ECMWF. THIS SHOULD BE
A QUICK HITTING SYSTEM WITH THE SFC HIGH ALREADY LOCATED EAST OF US
BY TUESDAY ALLOWING FOR A RETURN OF WEAK SOUTHERLY FLOW AND DRY
WEATHER. LATEST MODEL RUNS TONIGHT HAVE BEEN KEEPING THE
INSTABILITY ASSOCIATED WITH THE MONDAY SYSTEM ACROSS KANSAS AND WILL
JUST BE CALLING FOR RAIN SHOWERS OVER MOST NEBRASKA ZONES GIVEN THE
LACK OF INSTABILITY FOR THUNDERSTORMS. WILL CONTINUE TO KEEP A
MENTION OF ISOLATED THUNDERSTORMS SOUTH OF A HEBRON TO ALMA LINE.
&&
.PREV DISCUSSION... /ISSUED 100 AM CDT WED SEP 12 2012/
AVIATION...06Z KGRI TAF. A STRONG COLD FRONT WILL PASS THROUGH
KGRI JUST PRIOR TO DAWN AND RESULT IN A WIND SHIFT FROM SOUTH
SOUTHEAST TO NORTHEAST. NORTHEAST WINDS WILL QUICKLY GAIN STRENGTH
DURING THE DAY AND COULD GUST TO OVER 35 MPH AT TIMES FROM MID
MORNING THROUGH LATE AFTERNOON. MOST OF THE MORNING SHOULD BE DRY
WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON. RAIN WILL BE MOST LIKELY AT KGRI BETWEEN 5
PM AND 11 PM THIS EVENING WHEN OVER A HALF INCH OR RAIN COULD FALL.
THERE COULD BE A FEW CLAPS OF THUNDER BUT NOTHING STRONG OR
SEVERE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
245 AM CDT WED SEP 12 2012
.DISCUSSION...
COLD FRONT EXTENDED FROM NORTHWEST IOWA ACROSS NORTHEAST NEBRASKA
INTO SOUTH CENTRAL NEBRASKA ALONG A KSUX TO KEAR LINE AT 07Z.
SCATTERED SHOWERS AHEAD OF THE FRONT HAVE BECOME MORE NUMEROUS
DURING THE PAST HOUR OVER SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA.
00Z GFS AND 04Z HRRR APPEAR TO BE SIMILAR IN HAVING THE FRONT NEAR
A KOMA TO KHJH LINE BY 12Z...A BIT FASTER THAN THE 00Z NAM.
WILL ADD CHANCE OF SHOWERS AND ISOLATED THUNDER TO AREAS SOUTH OF
THE FRONT THIS MORNING BASED ON RADAR TRENDS AND SHORT RANGE
MODELS. WILL ALSO LIKELY TREND HIGHS TODAY TOWARD THE SOMEWHAT
COOLER GFS GUIDANCE BASED ON FASTER TIMING OF THAT MODEL.
OTHERWISE...STILL LOOKS GOOD FOR WIDESPREAD RAIN ACROSS MUCH OF
THE AREA TONIGHT WITH SYSTEM MOVING OUT OF SOUTHEAST AREAS
THURSDAY MORNING. FAIR AND DRY AFTER THAT WITH COOLER TEMPERATURES
HANGING AROUND FOR A CHANGE.
IN THE EXTENDED...AREA REMAINS UNDER THE INFLUENCE OF COOLER
NORTHWEST FLOW WITH ANOTHER STRONG TROUGH MOVING THROUGH THE
REGION EARLY NEXT WEEK. STILL SOME CHANCE OF SHOWERS WITH COLD
FRONT ON MONDAY WITH LOW POPS MAINTAINED FOR THAT PERIOD. SOME
DIFFERENCES BETWEEN THE GFS AND EURO IN HANDLING THIS FASTER FLOW
SO WILL HAVE TO SEE HOW CONSISTENT FUTURE MODEL RUNS BEHAVE.
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA...KLNK.
WILL LEAVE MENTION OF LOW LEVEL WIND SHEAR IN THE KOMA AND KLNK
TAFS OVERNIGHT AS 850MB WINDS ARE FORECAST AROUND 35 TO 45KTS WITH
DECREASING SFC SPEEDS. A COLD FRONT WILL MOVE THRU THE SITES
DURING THE TAF PERIOD. FRONT WILL BE OVER KOFK IN FIRST FEW HOURS
WITH POST FRONTAL SHOWERS EXPECTED TO DEVELOP BY 18Z. FRONT WILL
BE THRU KOMA AND KLNK AROUND 18Z WITH POST FRONTAL SHOWERS
EXPECTED BY LATE AFTERNOON/EARLY EVENING. TIGHT GRADIENT BEHIND
THE FRONT WILL CREATE GUSTY NORTHEAST WINDS INITIALLY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/KERN
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1107 PM EDT THU SEP 13 2012
.SYNOPSIS...
HIGH PRESSURE SLIPPING OFF THE MID-ATLANTIC COASTLINE WILL CONTINUE
FAIR WEATHER FOR ONE MORE NIGHT ACROSS THE REGION. A COLD FRONT WILL
SLIDE ACROSS THE REGION ON FRIDAY ALONG WITH SOME SHOWERS. BEHIND
THE COLD FRONT...SEASONABLY COOLER AIR WILL OVERSPREAD THE AREA FOR
THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
THROUGH LATE EVENING...WESTERN NEW YORK WAS MAINLY CLEAR...WITH
MID AND HIGH CLOUDS JUST WORKING IN TO FAR WESTERN PORTIONS OF THE
STATE. THIS CLOUD COVER SHOULD GRADUALLY MOVE FROM WEST TO EAST
OVERNIGHT. RADAR SHOWS A FEW LIGHT SHOWERS ACROSS CENTRAL LAKE
ERIE...AHEAD OF THE FRONT. MEANWHILE...A COLD FRONT WAS JUST
ENTERING FAR WESTERN PORTIONS OF LAKE ERIE AT 1100 PM. THE FRONT
ITSELF STILL IS DRY...BUT IT MAY PICK UP THE MOISTURE AND SHOWERS
STREAMING ACROSS CENTRAL LAKE ERIE. THE HRRR AND 18Z NAM HAS THIS
CLIPPING PERHAPS NIAGARA COUNTY DURING THE EARLY MORNING
HOURS...WHICH SEEMS REASONABLE.
ON FRIDAY THE COMPACT SHORTWAVE WILL BE DIGGING SOUTHWARD OVER THE
WESTERN GREAT LAKES. NEAR THE SURFACE A COLD FRONT WILL BE
CROSSING THE REGION FROM WEST TO EAST. RADAR CONFIRMS MODEL
FORECASTS OF AN ANAFRONTAL PASSAGE TO THE COLD FRONT WITH THE
BULK OF THE MOISTURE BEHIND THE FRONT WITH THE POTENT UPPER LEVEL
SHORTWAVE PROVIDING THE LIFT. RADAR SHOWS A SOLID LINE OF RAIN
SHOWERS...AND THE HRRR HOLDS THIS TOGETHER...BOTH OF WHICH
INCREASES CONFIDENCE IN AT LEAST SOME MEASURABLE PRECIPITATION
BEHIND THIS FRONT. BASED ON THIS...THE LATE EVENING UPDATE UPS
POPS...AND NUDGES TIMING BACK JUST A TAD. EXPECT A BAND OF CLOUDS
AND A NARROW BAND OF SHOWERS TO CROSS THE REGION...EARLY AFTERNOON
IN WESTERN PORTIONS...MID-AFTERNOON ACROSS THE GENESEE VALLEY AND
LATE AFTERNOON IN THE EASTERN LAKE ONTARIO REGION. IT IS POSSIBLE
THAT SOME CLEARING REACHES WNY TOWARD SUNSET. THIS CLEARING MAY
BE SHORT LIVED SOUTH OF LAKE ONTARIO AS COOLER AIR CONTINUES TO
POUR OVER THE EASTERN GREAT LAKES ON A NORTHWEST FLOW WITH PATCHY
LOW LEVEL STRATUS RETURNING ON FAVORABLE UPSLOPE AREAS SOUTH OF
LAKE ONTARIO EARLY EVENING.
THOUGH THERE HAS BEEN NO LIGHTNING ASSOCIATED WITH THESE SHOWERS
UPSTREAM TODAY...WILL CONTINUE TO MENTION SLIGHT CHC FOR THUNDER AS
MODELS DEPICT AN INCREASE IN INSTABILITY FRIDAY WITH UPWARDS TO 500
J/KG OF SBCAPE.
WITH THE PROGRESSIVE NATURE OF THIS COLD FRONT EXPECT QPF TO
GENERALLY BE A TENTH OR LESS TOWARDS THE SOUTH...WHILE FARTHER NORTH
ACROSS THE NORTHERN NIAGARA FRONTIER AND EASTERN LAKE ONTARIO
REGION UPWARDS OF TWO TENTHS OR SO OF AN INCH OF RAIN MAY FALL FRIDAY.
TEMPERATURES TONIGHT WILL COOL INTO THE MID AND UPPER 50S TOWARDS
THE GENESEE VALLEY AND AREAS EAST UNDER THE MAINLY CLEAR
SKIES...WHILE AREAS TO THE WEST WILL FAVOR 60 OR ABOVE AS CLOUDS
INCREASE. ON FRIDAY WITH THE COLD FRONT ACROSS WNY IN THE
MORNING...EXPECT THE WARMEST AREAS TO BE ACROSS THE EASTERN LAKE
ONTARIO REGION WHERE A FEW 80S WILL BE FOUND UNDER +13 TO +14C AT
850 HPA. TO THE WEST HIGHS WILL GENERALLY BE IN THE LOW AND MID
70S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT SHOULD BE EAST OF THE AREA FRIDAY NIGHT. SHARP MID LEVEL
DRY INTRUSION WILL PUSH INTO THE AREA IN WAKE OF THE FRONT...AS WELL
AS A MUCH COOLER AIR MASS. OVER-LAKE INSTABILITY WILL CERTAINLY BE
INCREASING THROUGH THE NIGHT AND EARLY SATURDAY...AS 850 MB
TEMPERATURES DROP TO NEAR +5C OR MAYBE A BIT COLDER. LINGERING LOW
LEVEL MOISTURE AND CYCLONIC FLOW MAY BE ABLE TO OVERCOME ENTRAINMENT
OF MID LEVEL DRY AIR TO DEVELOP SOME MINIMAL LAKE RESPONSE SOUTHEAST
OF LAKE ONTARIO...BUT ANYTHING THAT DOES DEVELOP SHOULD BE SHORT
LIVED AND LIGHT IN NATURE.
HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR FAIR WEATHER WEEKEND.
THE AIR MASS LOOKS QUITE DRY...THEREFORE EXPECT A LARGE DIURNAL
TEMPERATURE SWING. FAVORABLE RADIATIONAL COOLING CONDITIONS SATURDAY
NIGHT/SUNDAY MORNING WILL ALLOW TEMPERATURES TO DROP INTO THE MID TO
UPPER 30S INLAND. THIS WILL BRING A POTENTIAL FROST TO SOME
LOCATIONS ALONG THE SOUTHERN TIER AND EAST OF LAKE ONTARIO.
SATURDAY LOOKS TO BE THE COOLEST WEEKEND DAY WITH MOST HIGHS IN THE
MID TO UPPER 60S. WARM AIR ADVECTION DEVELOPS BY SUNDAY AS THE HIGH
STARTS TO SHIFT EAST...THIS SHOULD ALLOW TEMPERATURES TO REBOUND
BACK INTO THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
SOME MODEL DISCREPANCIES DEVELOP BY MONDAY. THE GFS IS MUCH
FASTER THAN THE ECMWF/CANADIAN WITH THE SHORTWAVE ENERGY LIFTING
OUT OF THE SOUTHERN PLAINS...WHILE SLOWER SOLUTIONS ALLOWS FOR
SOME PHASING OF NORTHERN AND SOUTHERN STREAM WAVES. AT THIS
POINT...WILL OFFER A MODEL BLEND AND BRING SOME LIMITED
PROBABILITIES INTO THE AREA AHEAD OF THE COLD FRONT FOR MONDAY.
THE UPPER LEVEL FLOW LOOKS TO BECOME DEEPLY AMPLIFIED HEADING INTO
THE MIDDLE OF NEXT WEEK...WITH AN IMPRESSIVE WESTERN CONUS RIDGE AND
CENTRAL PLAINS/GREAT LAKES TROUGH EVOLVING. LATEST MEDIUM RANGE
MODELS AND ENSEMBLES IN GENERAL AGREEMENT BRINGING SHARP COLD FRONT
LATER TUESDAY INTO WEDNESDAY. DECENT POTENTIAL FOR SHOWERS WITH THE
FRONTAL PASSAGE FOLLOWED BY A SHOT OF RATHER CHILLY AIR. THERE LOOKS
TO BE SOME AIRMASS MODIFICATION...BUT WEDNESDAY STILL COULD BE
RATHER COOL WITH SOME LOCATIONS STRUGGLING TO GET OUT OF THE 50S.
PATTERN LOOKS PROGRESSIVE WITH WARM AIR ADVECTION PATTERN RESUMING
THURSDAY AHEAD OF NEXT APPROACH FRONTAL ZONE.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AT 00Z...CONDITIONS WERE VFR ACROSS THE REGION. THERE WAS NO FOG
AT TAF SITES LAST NIGHT...AND WITH MORE CLOUD COVER TONIGHT THERE
SHOULD EVEN BE LESS VALLEY FOG. THIS SHOULD KEEP CONDITIONS VFR
OVERNIGHT.
A COLD FRONT WILL CROSS THE REGION ON FRIDAY. SHOWERS SHOULD BE
MOST WIDESPREAD BEHIND THE FRONT...WHERE CIGS MAY LOWER TO MVFR
FOR A PERIOD. TSTMS CAN/T BE RULED OUT...BUT APPEAR UNLIKELY GIVEN
THE MARGINAL AMOUNT OF INSTABILITY.
OUTLOOK...
SATURDAY AND SUNDAY...MAINLY VFR.
MONDAY AND TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/ASSOCIATED
MVFR.
&&
.MARINE...
HIGH PRESSURE SLIPPING OFF THE MID ATLANTIC COASTLINE WILL GIVE ONE
MORE QUIET NIGHT ON THE LAKES AND RIVERS. ON FRIDAY A COLD FRONT
WILL CROSS THE REGION FROM WEST TO EAST WITH A NARROW BAND OF
SHOWERS...PRIMARILY BEHIND THE FRONT. AS WINDS SHIFT TO NORTHWEST
AND WITH SHARP COOLING ALOFT EXPECT WAVES TO INCREASE LATER FRIDAY
AND FRIDAY NIGHT WITH SMALL CRAFT CONDITIONS ON CENTRAL AND EASTERN
PORTIONS OF LAKE ONTARIO. HAVE THEREFORE ISSUED A SCA FOR THESE
SECTIONS OF LAKE ONTARIO. WITH THE BOUNDARY LAYER FLOW MORE
PERPENDICULAR TO LAKE ERIE FRIDAY EVENING AND NIGHT WAVES WILL
INCREASE...THOUGH LIKELY REMAINING BELOW SMALL CRAFT CONDITIONS.
A STEADY NORTHWEST FLOW WILL CONTINUE TO START THE WEEKEND THOUGH
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA.
&&
.CLIMATE...
ALL THREE OF OUR CLIMATE SITES REACHED AT LEAST 80F TODAY
(THURSDAY) AND THE YEARLY NUMBER OF 80F OR GREATER DAYS HAS
INCREASED. EVEN WITH THE INCREASE...ALL THREE SITES CONTINUE TO
RANK THIRD FOR GREATEST NUMBER OF 80F DAYS IN A YEAR.
BUFFALO (SINCE 1944)
1 83 1949
2 82 1959
3 79 2012
AVG: 54 DAYS
ROCHESTER (SINCE 1871)
1 91 1959
2 86 2007
3 85 2012
AVG: 59 DAYS
WATERTOWN (SINCE 1949)
1 75 1949
2 73 1959
3 72 2012
AVG: 45 DAYS
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM FRIDAY TO 6 AM EDT SATURDAY FOR
LOZ043-044.
SMALL CRAFT ADVISORY FROM 8 PM FRIDAY TO 6 AM EDT SATURDAY
FOR LOZ045.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
817 PM EDT THU SEP 13 2012
.SYNOPSIS...
THE CENTER OF HIGH PRESSURE WILL MOVE SLOWLY OFFSHORE FROM THE
NORTHEAST STATES THROUGH FRIDAY. A WEAK COLD FRONT WILL DROP SOUTH
INTO THE AREA ON SATURDAY AND LIKELY STALL ACROSS OR JUST SOUTH OF
THE AREA SUNDAY THROUGH EARLY NEXT WEEK. AN APPROACHING STORM
SYSTEM WILL BRING UNSETTLED WEATHER TO THE FORECAST AREA THROUGH
THE MID-WEEK PERIOD OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 745 PM THURSDAY...NOT MUCH TO CHANGE FROM THE PREVIOUSLY
ISSUED FORECAST. MAINLY INITIALIZING WITH CURRENT WX OBSERVATIONS
FOR THE INDIVIDUAL ELEMENTS AND SAT IMAGERY FOR SKY CONDITIONS.
WILL FOLLOW IT UP WITH THE MESHING/TRENDING OF EACH ELEMENT TO THE
OVERNIGHT FORECAST. LATEST HRRR INDICATES THE ISOLATED CHANCE FOR
-SHRA AFTER MIDNIGHT THROUGH DAYBREAK FRI. WILL INDICATE THE
SLIGHT CHANCE ACROSS THE ADJACENT COASTAL WATERS AND JUST ONSHORE
WHICH INCLUDES THE IMMEDIATE COASTAL ZONE WITHIN EACH COASTAL
COUNTY.
PREVIOUS DISCUSSION..............................................
AS OF 300 PM THURSDAY...HIGH PRESSURE HAS MOVED WELL EAST OF THE
NEW ENGLAND COASTLINE BUT A RIDGE AXIS EXTENDS WEST INTO THE MID-
ATLANTIC STATES. BEING SOUTH OF THIS SURFACE RIDGE...NORTHEAST
WINDS CONTINUE ACROSS THE CAROLINAS...AND SHOULD THROUGH TONIGHT.
THE AIR MASS ADVECTING ONSHORE ACTUALLY ORIGINATES AT HIGH LATITUDES
JUST SOUTH OF GREENLAND BUT HAS BEEN HEAVILY MODIFIED BY ITS 3000
MILE JOURNEY ACROSS THE WARM WESTERN ATLANTIC. IN THE LOW LEVELS THE
AIR MASS NOW ALMOST RESEMBLES SUBTROPICAL MARITIME AIR WITH WARMING
TEMPERATURES...STEEPENING LAPSE RATES AND FAIRLY LARGE MOISTURE
CONTENT.
AT 500 MB A NARROW RIDGE IS SQUEEZED IN BETWEEN SHORTWAVE ENERGY
PASSING BY TO THE NORTHWEST AND A WEAK UPPER LOW SEVERAL HUNDRED
MILES OFF THE NC COAST. THE 12Z MHX SOUNDING SHOWED A PROMINENT
SUBSIDENCE INVERSION RIGHT AT 850 MB. BOTH THE GFS AND NAM MODELS
SHOW THIS INVERSION WEAKENING TONIGHT AND ACTUALLY DISSIPATING
COMPLETELY ACROSS SOUTHEASTERN NC AFTER 06Z. SEVERAL CLUSTERS OF
SHALLOW CONVECTIVE CLOUDS OFF THE SOUTHERN OUTER BANKS WILL ADVECT
WESTWARD OVERNIGHT AND SHOULD BRING ISOLATED SHOWER ACTIVITY INTO
THE CAPE FEAR REGION. MODEL FORECAST SOUNDINGS SUPPORT ENOUGH LOW
LEVEL MOISTURE AND STEEP ENOUGH LAPSE RATES IN THE 1000-700 MB LAYER
TO SUPPORT SHALLOW CONVECTION. WE`RE FORECASTING THE ODDS OF
MEASURABLE RAIN AT ONLY 20 PERCENT AT ILM...IN BETWEEN THE GFS AND
NAM MOS. OUR FORECAST POPS ARE ONLY 5-10 PERCENT FARTHER INLAND AND
ACROSS THE SC COAST.
WITH THE AIR MASS CONTINUING TO MODIFY AND WITH ADDITIONAL CLOUDS
EXPECTED TONIGHT OUR FORECAST LOWS ARE WARMER THAN THOSE OBSERVED
OVER THE PAST SEVERAL DAYS. LOWER 60S ARE FORECAST ALONG AND WEST OF
I-95 WITH MID 60S EASTWARD TO THE COAST. SOUTHERN NEW HANOVER COUNTY
AND PERHAPS THE BEACHES OF GEORGETOWN COUNTY MAY SEE LOWS NEAR 70
DEPENDING ON EXACTLY HOW MUCH ONSHORE WIND COMPONENT REMAINS LATE
TONIGHT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY... SOME UPPER LEVEL FORCING WILL PRODUCE
CLOUDS THROUGH FRI BUT DRY AIR AND SUBSIDENCE WILL PERSIST IN THE
MID LEVELS. THEREFORE EXPECT MORE IN THE WAY OF CIRRUS AND CU
DEVELOPMENT. CAN NOT RULE OUT A STRAY SHOWER...BUT WILL KEEP JUST
CLOUDS FOR NOW.
A COLD FRONT MOVING DOWN FROM THE GREAT LAKES WILL REACH THE
APPALACHIANS ON FRI BUT THE LATEST MODELS DO NOT SHOW A GREAT PUSH
FROM THE MID TO UPPER LEVELS. THE MID TO UPPER RIDGE MOVES OFF THE
COAST EARLY FRIDAY AND ALTHOUGH WE GET INTO A VERY BRIEF SW
FLOW WITH SOME UPPER LEVEL DIFLUENCE...THE NORTHERN STREAM
REMAINS VERY PROGRESSIVE AND THE H5 TROUGH MOVES QUICKLY OFF TO
THE EAST WHILE NEVER REACHING TOO FAR SOUTH. THEREFORE THE COLD
FRONT DOES NOT GET MUCH OF A PUSH BEFORE THE MID TO UPPER FLOW
BECOMES ZONAL ON SAT AND LEAVES THIS BOUNDARY LAYING FLAT IN THE
VICINITY SAT AFTN THROUGH THE END OF THE PERIOD. THIS BOUNDARY
WILL PRODUCE GREATER CONVERGENCE AT THE LOW LEVELS AND
DEVELOPMENT OF CLOUDS BUT IT LOOKS LIKE CHC OF SHWRS WILL REMAIN
SLIM. NAM SHOWS BULLS-EYE OF GREATER PCP WATER OVER THE TIP OF CAPE
FEAR FRI AND THEN AGAIN LATE SAT AS BOUNDARY COMES TO REST ACROSS
AREA. FOR NOW THINK IT WILL BE MORE IN THE WAY OF CLOUDS AND WILL
KEEP SILENT POPS. HIGHS WILL BE IN THE MID 80S WITH LOWS IN THE
MID 60S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...SPLIT FLOW REGIME AT 500MB SUNDAY
TRANSITIONS TO BECOME HIGHLY AMPLIFIED ONCE AGAIN MON-THUR AS A DEEP
UPPER TROUGH DEVELOPS ACROSS THE CENTRAL CONUS. SUNDAY WILL BE THE
LEAST-UNSETTLED WEATHER DAY OF THE EXTENDED AS WEAK S/W RIDGING
ALOFT FORCES THE MID-LEVELS TO REMAIN RELATIVELY DRY. THIS
SUPPRESSES MOST CONVECTION...BUT LOW LEVEL E/NE FLOW WILL ADVECT
ENOUGH MOISTURE INTO THE COLUMN THAT ISOLATED SHOWERS/TSTMS ARE
POSSIBLE...AND WILL CONTINUE INHERITED SCHC POP. TEMPS SUNDAY WILL
BE JUST BELOW CLIMO IN COOL NE FLOW.
A HIGHLY UNSETTLED PERIOD OF WEATHER LOOKING MORE LIKELY
NOW...BEGINNING LATE MONDAY AND PERSISTING THROUGH MID-WEEK. MID
LEVEL IMPULSES WILL ROTATE UP ALONG THE LEE SIDE OF DEVELOPING
FULL-LATITUDE TROUGH ACROSS THE PLAINS. THIS TROUGH WILL SIT AND
RELOAD ACROSS THE SAME AREA DURING THE WEEK. AS THIS OCCURS...DEEP
SOUTH FLOW DEVELOPS AND INCREASES ACROSS THE CAROLINAS AS A WARM
FRONT LIFTS NORTH LATE MONDAY. THIS TRANSPORTS A HIGH THETA-E RIDGE
INTO THE AREA WHICH WILL SERVE AS FUEL FOR WIDESPREAD SHOWERS AND
THUNDERSTORMS BEGINNING LATE MONDAY...AND PERSISTING THROUGH
WEDNESDAY. THE WARM FRONT WHICH LIFTS NORTH MONDAY NIGHT WILL WAVER
AS A STALLED BOUNDARY NEAR THE AREA...ON WHICH WAVES OF LOW PRESSURE
WILL DEVELOP AND PUSH NE BENEATH ANY MID LEVEL IMPULSES...EACH ONE
SERVING TO RENEW SHOWERS/TSTMS. TIMING THESE FEATURES IS DIFFICULT
EVEN IN THE SHORT TERM...SO WILL CARRY HIGH-CHC POP LATE MONDAY AND
TUESDAY...DECREASING TO LOW CHC WEDNESDAY...AND THERE IS POTENTIAL
FOR SIGNIFICANT RAINFALL DURING THE WEEK. FRONT WILL PUSH OFFSHORE
LATE WEDNESDAY BRINGING DRIER AIR INTO THE REGION BY THURSDAY.
TEMPS THROUGH THE WEEK WILL BE AROUND...OR A FEW DEGREES
BELOW...CLIMO FOR HIGHS DUE TO CLOUDS/PRECIP...BUT WELL ABOVE FOR
LOWS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...SURFACE RIDGE REMAINS TO OUR NORTH GIVING US NE-E WINDS
THROUGH THIS TAF VALID PERIOD. CU/STRATOCU WILL BE PERSISTENT
OVERNIGHT BUT SHOULD REMAIN IN THE VFR LEVEL WITH NO CEILINGS
ANTICIPATED. THERE IS STILL UNCERTAINTY WITH RESPECT TO SHOWERS
THAT MAY ROLL ONSHORE NEAR ILM ESPECIALLY TOWARDS MORNING. RADAR
CURRENTLY SHOWS SHOWERS OFFSHORE TO THE NORTHEAST OF ILM MOVING
SOUTHWEST...BUT ALL PROGS TEND TO KEEP THE BEST POTENTIAL FOR
RAINFALL NE-E OF ILM THROUGH 12Z-18Z. AT LBT WILL INDICATE TEMPO
MVFR VISIBILITIES IN THE PRE-DAWN HOURS. DUE TO LIMITED MOISTURE
DO NOT THINK ANY IFR CIGS/VSBYS WILL OCCUR. COULD BE A BETTER CHANCE
OF SHOWERS AT THE COAST TERMS TOMORROW AFTERNOON WITH VFR LEVEL
LOW CEILINGS.
THE EXTENDED OUTLOOK THROUGH MONDAY...POTENTIAL FOR BRIEF REDUCED
VSBYS IN BR AT FOG PRONE TERMINALS KLBT/KFLO IN THE PRE-DAWN HOURS
THROUGH SUNDAY. OTHERWISE EXPECT VFR...WITH A SLIGHT CHANCE OF
SHOWERS SUNDAY WITH A BETTER CHANCE MONDAY AND TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 745 PM THURSDAY...SFC RIDGING EXTENDING FROM THE CENTER OF
HIGH PRESSURE MOVING OFFSHORE FROM THE NE STATES...WILL CONTINUE
ACROSS THE ILM WATERS OVERNIGHT INTO FRIDAY. SFC PRESSURE PATTERN
AND A SLIGHTLY RELAXED SFC PG COMPARED TO LAST NIGHT...WILL YIELD
NE-ENE WINDS AT 10-15 KT. SIGNIFICANT SEAS WILL RANGE BETWEEN 2
AND 4 FT...AND WILL BE DOMINATED BY THE 4 TO 6 SECOND PERIOD WIND
DRIVEN WAVES RUNNING AT 2 TO 4 FT. AN UNDERLYING 1 FT OR LESS
EASTERLY GROUND SWELL EXHIBITING 10-12 SECOND PERIODS...WILL
CONTINUE TO AFFECT THE ILM WATERS OVERNIGHT.
PREVIOUS DISCUSSION...............................................
AS OF 300 PM THURSDAY...A RIDGE OF HIGH PRESSURE EXTENDING ACROSS
THE MID-ATLANTIC STATES AND OFFSHORE WILL MAINTAIN NORTHEAST WINDS
ACROSS THE CAROLINA COASTAL WATERS TONIGHT. THE STRONGEST WINDS...
AROUND 15 KNOTS WITH SLIGHTLY HIGHER GUSTS...ARE EXPECTED TO
CONTINUE THROUGH ABOUT 2 AM FRIDAY...WITH WINDS DIMINISHING TOWARD
10 KNOTS LATE. A POCKET OF UNSTABLE AIR NEAR THE SOUTHERN OUTER
BANKS IS EXPECTED TO APPROACH THE CAPE FEAR REGION LATE THIS EVENING
BRINGING ISOLATED SHOWERS ACROSS THE WATERS. THE SOUTH CAROLINA
COASTAL WATERS WILL REMAIN LARGELY SOUTH OF THIS FEATURE AND SHOULD
REMAIN DRY.
SPECTRAL WAVE DATA FROM FRYING PAN SHOALS BUOY SHOWS A BROAD
SPECTRUM OF WAVE ENERGY FROM 4-5 SECOND WIND WAVES UP THROUGH A WEAK
10-11 SECOND SWELL. THE DOMINANT PERIOD IS 5 SECONDS INDICATING
LOCAL WINDS ARE HAVING THE LARGEST IMPACT ON THE CURRENT SEA STATE.
SEA HEIGHTS WITHIN 20 MILES OF SHORE SHOULD AVERAGE 3-4 FT THIS
EVENING...SUBSIDING TO 2-3 FT AFTER MIDNIGHT.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...SFC HIGH PRESSURE WILL WEAKEN ON FRI AS
IT CONTINUES TO RIDGE DOWN FROM SYSTEM MOVING FURTHER OFF THE NEW
ENGLAND COAST. THIS WILL PRODUCE A WEAKER NE-E FLOW AROUND 10 TO
15 KTS THROUGH MUCH OF THE PERIOD. A COLD FRONT WILL DROP SOUTH ON
SATURDAY WITH AN ON SHORE FLOW AHEAD OR SOUTH OF THE FRONT. WINDS
SHOULD COME AROUND TO THE NE AGAIN IF BOUNDARY MAKES ITS WAY FAR
ENOUGH SOUTH OF THE LOCAL WATERS. ALTHOUGH THE WINDS REMAIN AROUND
10 KTS THROUGH MOST OF THE PERIOD...A VERY LONG PERIOD EASTERLY SWELL
UP TO 16 SECONDS...FROM NADINE...WILL MAKE IT INTO LOCAL WATERS
SAT AFTN AND SHOULD PEAK SAT NIGHT. THIS WILL TRY AN MAKE IT INTO
WATERS BUT OVERALL SEAS WILL REMAIN 2 TO 4 FT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...NE WINDS AT LESS THAN 10 KTS THROUGH MOST OF
SUNDAY WILL VEER GRADUALLY BY MONDAY TO THE SOUTHEAST IN RESPONSE TO
HIGH PRESSURE DRIFTING ACROSS THE NORTHEAST. AS WINDS VEER TO THE
SE...THEY REMAIN LESS THAN 10 KTS THROUGH MONDAY MORNING. BY MONDAY
AFTN...PRESSURE GRADIENT INCREASES IN RESPONSE TO A STORM SYSTEM AND
FRONT SLOWLY APPROACHING FROM THE MIDWEST. WINDS VEER TO THE SOUTH
BY TUESDAY WHILE INCREASING TO 10-15 KTS...POSSIBLY UP TO 20 KTS
NEAR THE 20NM BOUNDARY. SEAS WILL BE FORCED BY A COMBINATION OF WIND
WAVES AND A 10-12 SEC SE SWELL THANKS TO TS NADINE. SIGNIFICANT WAVE
HEIGHTS OF 2-4 FT PERSIST SUNDAY AND MUCH OF MONDAY...BEFORE
BUILDING TO 3-5 FT TUESDAY IN RESPONSE TO THE INCREASED WINDS.
ONGOING FORECAST SUGGESTS CONDITIONS REMAINING JUST BELOW SCEC
CRITERIA...BUT A SCEC MAY BE NEEDED SOMETIME TUESDAY IF WINDS BECOME
STRONGER THAN CURRENTLY ANTICIPATED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH/TRA
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
123 AM EDT WED SEP 12 2012
.SYNOPSIS...
FAIR WEATHER WILL PREVAIL THROUGH FRIDAY AS CANADIAN HIGH PRESSURE
SETTLES INTO THE REGION. AN APPROACHING COLD FRONT MAY BRING A FEW
SHOWERS OVER THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 11:00 PM TUESDAY...RIDGING SFC AND ALOFT TO DOMINATE THE ILM
CWA OVERNIGHT. SUBSIDENCE IN THE MID-LAYERS TO PREVENT ANY VERTICAL
DEVELOPMENT WITH THE CU/SC THAT DEVELOPS OVER THE ADJACENT ATLANTIC
WATERS AND SPORADICALLY MOVES ONSHORE DURING THIS PERIOD. THE NE-E
FLOW IN THE LOWER LEVELS WILL FORCE/LIFT WHAT MOISTURE THAT IS
AVAILABLE UPWARDS...WITH OROGRAPHIC LIFT AIDING ANY CU/SC
DEVELOPMENT WELL INLAND WITHIN THE ILM CWA. WILL GO WITH MOSTLY
CLEAR TO PTLY CLOUDY FOR SKY CONDITIONS TONIGHT. HRRR INDICATES
SPOTTY PCPN OR ISOLATED SHRA TO DEVELOP OVER THE ADJACENT
WATERS...AND PUSH ONSHORE BEFORE DISSIPATING ALTOGETHER. FOG
ALGORITHM PORTRAITS PATCHY TO AREAS OF FOG DEVELOPMENT FOR A SHORT
4-6 HR WINDOW ENDING/DISSIPATING BY 8-9 AM WEDNESDAY.
DRY AND RELATIVELY COOL WEATHER TO CONTINUE THROUGHOUT THE NEAR TERM
AS CANADIAN HIGH PRESSURE CENTERED ACROSS THE MID-ATLANTIC STATES TO
MARTHAS VINEYARD WHICH EVIDENTLY MAINTAINS A STEADY BUT LIGHT NE-E
FLOW ESPECIALLY FELT ACROSS THE COASTAL CAROLINAS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 PM TUESDAY...FALL LIKE WEATHER WILL CONTINUE THROUGH MID
WEEK AS CANADIAN HIGH PRESSURE SETTLES DOWN OVER THE SOUTHEAST
WHILE SHIFTING SLOWLY EAST. AS THE CENTER SLIPS OFF THE NEW
ENGLAND COAST...IT WILL CONTINUE TO RIDGE DOWN INTO THE CAROLINAS.
THIS WILL HELP VEER WINDS AROUND THROUGH THE PERIOD TO THE
NORTHEAST WED INTO THURS AND EAST BY END OF THE PERIOD WHICH WILL
PRODUCE A SLIGHT INCREASE IN MOISTURE COMING FROM THE ATLANTIC
WATERS. AN OVERALL RISE IN MOISTURE WILL BRING PCP WATER VALUES
FROM CLOSE TO A HALF INCH WED TO OVER AN INCH BY LATE THURS IN
MOISTURE COMING IN FROM THE E-NE. THEREFORE EXPECT SUNNY WEATHER
ON WED BUT SHOULD SEE MORE IN THE WAY OF CU DEVELOPMENT THURS
AFTERNOON ESPECIALLY ALONG SEA BREEZE BOUNDARY AND MAINLY OVER
NORTH CAROLINA ZONES. MOISTURE PROFILES AND SOUNDING DATA SHOW
MOISTURE LOCKED IN BELOW INVERSION REACHING UP TO 90% IN THE 2-4K
FT LEVEL ON THURS. EASTERLY FETCH OF MOISTURE MAY HELP TO PRODUCE
SOME FOG OR LOW STRATUS ON FRI IN THE EARLY MORNING CLOSER TO THE
COAST.
IN THE MID TO UPPER LEVELS THE RIDGE BECOMES MORE PRONOUNCED OVER
THE EAST COAST...BUT GETS SQUEEZED OUT BY END OF PERIOD BY BACK
BUILDING TROUGH OVER THE ATLANTIC AND TROUGH DIGGING DOWN FROM THE
UPPER GREAT LAKES. OVERALL EXPECT PLENTY OF DRY AIR AND SUBSIDENCE
THROUGHOUT THE MID LEVELS THROUGHOUT MOST OF WED AND INTO THURS.
AS FOR TEMPS...HEIGHTS WILL BE RISING THROUGH MID WEEK WITH A RISE
IN 850 TEMPS FROM 12C ON WED UP CLOSE TO 15C BY THURS. THE VERY DRY
AIR INITIALLY WILL CONTINUE TO PRODUCE LARGE DIURNAL SWINGS BUT THE
INCREASED MOISTURE IN THE LOW LEVELS BY THURS WILL BRING DEWPOINT
TEMPS UP ABOUT 10 DEGREES TO NEAR 65 CLOSER TO THE
COAST...ESPECIALLY NC COAST. THEREFORE EXPECT DAY TIME HIGHS
RISING A COUPLE OF DEGREES BETWEEN WED AND THURS...BETWEEN 80 AND
85 MOST PLACES. OVERNIGHT LOWS WILL INCREASE ALSO FROM CLOSER TO
60 WED IN MORE IDEAL RADIATIONAL COOLING CONDITIONS TO CLOSER TO
65 BY FRI MORNING.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...LARGE 5H RIDGE ACROSS THE EAST TRANSITIONS TO
MID-LEVEL SPLIT FLOW AS A NORTHERN STREAM LOW DRAGS A COLD FRONT
TOWARDS THE CAROLINAS ON SATURDAY. THIS FRONT TRIES TO PUNCH INTO A
VERY DRY AIR MASS...AND IS ACCOMPANIED ONLY BY WEAK (AND WEAKENING)
MID-LEVEL FORCING. WITH PWATS STILL ONLY AROUND ONE-INCH...AND MEX
P24 VALUES STILL WELL BELOW CLIMO...EXPECT THE WKND TO BE MOSTLY
DRY. HOWEVER...CANNOT RULE OUT SOME ISOLATED SHOWERS EITHER SAT OR
SUN AND THUS WILL KEEP INHERITED SCHC POP.
A MORE ROBUST MID-LEVEL SYSTEM ROTATES NORTHEAST FROM THE GULF COAST
REGION FOR THE BEGINNING OF THE WEEK...AND IS ACCOMPANIED BY AN
INCREASING SURFACE REFLECTION AND WARM FRONT. ALTHOUGH IT APPEARS
BEST FORCING REMAINS WEST OF THE IMMEDIATE CWA...LIFT ALONG THE WARM
FRONT IN A MOISTENING AIR MASS WILL PROVIDE INCREASING SHOWER
POTENTIAL MONDAY INTO TUESDAY AND WILL CARRY LOW-CHC FOR NOW...BUT
THIS WILL BE THE BEST CHANCE FOR RAIN THROUGH THE EXTENDED.
MAX TEMPS WILL BE SLIGHTLY ABOVE CLIMO FRI/SAT BEFORE FALLING BACK
TO NEAR SEASONABLE LEVELS FOR THE BEGINNING OF THE WEEK. MINS EACH
NIGHT WILL BE AROUND TO JUST ABOVE CLIMATOLOGICAL NORMS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR TO PREVAIL THROUGH THE PERIOD...WITH
EXCEPTION OF POSSIBLE MVFR AT KLBT BEFORE DAYBREAK DUE TO FOG.
OVERNIGHT...GENERALLY LIGHT NORTHEAST WINDS WILL CONTINUE. GIVEN
IDEAL RADIATIONAL COOLING OVERNIGHT...CANNOT RULE OUT MVFR FOG AT
KLBT JUST BEFORE DAYBREAK. GIVEN LOWERED CONFIDENCE HAVE OPTED TO
INTRODUCE TEMPO GROUP. AFTER DAYBREAK...VFR WILL PREVAIL WITH
NORTHEAST WINDS GRADUALLY INCREASING TO AOB 10 KTS. GIVEN FCST
SOUNDINGS AND GUIDANCE...CONTINUE TO ANTICIPATE FEW/SCT DIURNAL CU
TO DEVELOP ACROSS THE AREA IN THE AFTERNOON...AROUND 5-6KFT. SKIES
WILL CLEAR AND WINDS WILL BECOME LIGHT INTO THE OVERNIGHT HOURS.
THE EXTENDED OUTLOOK THROUGH SUNDAY...POTENTIAL FOR BRIEF REDUCED
VSBYS AT FOG PRONE TERMINALS KCRE/KLBT IN THE PRE-DAWN HOURS
THURSDAY THROUGH SUNDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 11:05 PM TUESDAY...ELONGATED CENTER OF HIGH PRESSURE EXTENDED
FROM THE MID-ATLANTIC STATES NE TO MARTHAS VINEYARD. THIS PRESSURE
PATTERN WILL YIELD A NE-E WIND DIRECTION. A SLIGHTLY PINNED SFC PG
ACROSS THE EASTERN CAROLINAS WILL PRODUCE 10-15 KT WIND SPEEDS.
DECAYING TROPICAL SWELL AND WIND DRIVEN WAVES TO COMBINE TO PRODUCE
2 TO 4 FT OVERALL SEAS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
CANADIAN HIGH PRESSURE WILL SETTLE DOWN OVER THE SOUTHEAST WHILE
SHIFTING SLOWLY EAST. AS THE CENTER SLIPS OFF THE NEW ENGLAND
COAST...IT WILL CONTINUE TO RIDGE DOWN INTO THE CAROLINAS. THIS WILL
HELP VEER WINDS AROUND THROUGH THE PERIOD FROM N-NE EARLY WED TO NE
TO E BY THURS NIGHT. GRADIENT FLOW WILL WEAKEN WITH WINDS NE
AROUND 15 KTS AND UP TO 20 IN OUTER WATERS ON WED. BY LATE THURS
WINDS WILL BE DOWN TO 10 TO 15 KTS.
OVERALL SEAS WILL DIMINISH A BIT BUT THE ONSHORE PUSH WILL KEEP
SEAS IN THE 2 TO 4 FT RANGE. LONGER PERIOD SWELL WILL DROP OFF BY
WED EVENING.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...HIGH PRESSURE RIDGING DOWN THE COAST
THROUGH THE PERIOD CREATES PREDOMINANTLY E/NE WINDS ACROSS THE
WATERS. THE PRESSURE GRADIENT WILL EASE THROUGH THE WKND...SO THE
STRONGEST WINDS...10-15 KTS...WILL OCCUR EARLY FRIDAY...BEFORE
FALLING TO LESS THAN 10 KTS THROUGH THE REST OF THE PERIOD. BY
LATE SUNDAY...RETURN FLOW WILL ONCE AGAIN DEVELOP...TURNING WINDS
TO THE SW BUT REMAINING LESS THAN 10 KTS. SEAS WILL BE PRIMARILY
2-4 FT THANKS TO A NE WIND WAVE..BUT MAY BUILD SUNDAY AS SOME
INCREASING LONG PERIOD SWELL FROM A TROPICAL DISTURBANCE WORKS
INTO THE LOCAL WATERS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/8
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...SGL/8
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1058 AM CDT WED SEP 12 2012
.DISCUSSION...
CHALLENGE WITH MORNING UPDATE CONCERNS FIRE WEATHER HEADLINES.
MODELS ARE IN GOOD AGREEMENT AND WILL USE A BLENDED SOLUTION.
15 UTC REGIONAL RADARS SHOW BAND OF RAIN SHOWERS FROM MITCHELL SD
TO ST CLOUD MN...COINCIDENT WITH 700 HPA MOISTURE GRADIENT AND
FRONTOGENESIS. THIS AREA OF PRECIPITATION WILL CONTINUE A SLOW
EASTWARD PROGRESSION AS UPPER LOW ACROSS NORTHERN MANITOBA MOVES
ACROSS HUDSON BAY. HIGH LEVEL CLOUDS ACROSS SOUTHEAST FORECAST
AREA WILL ALSO DISSIPATE AND MOVE EAST THROUGH THE DAY. FARTHER
NORTH...CLEAR SKIES WILL BE THE RULE GIVEN A VERY DRY BOUNDARY
LAYER AND CONVECTIVE TEMPERATURES IN THE 90S. TEMPERATURES STILL
ON TRACK TO REACH THE MID 60S TO NEAR 70 DEGREES. WITH DEW POINT
TEMPERATURES DROPPING INTO THE 20S...MINIMUM RH VALUES SHOULD BE
15 TO 20 PERCENT REGION-WIDE.
MODEL SOUNDINGS SUGGEST BOUNDARY LAYER WILL DEEPEN TO 700 HPA BY
MID-LATE AFTERNOON. LATEST RAP SHOWS A CORRIDOR OF 40 KTS AT 700
HPA FROM COOPERSTOWN TO DETROIT LAKES. ASSUMING EVENTUAL CLEARING
FROM WEST TO EAST AND EFFICIENT HEATING/MIXING...THINK WINDS WILL
INCREASE ABOVE 20 TO 25 MPH CRITICAL FIRE WEATHER THRESHOLD ALONG
AND NORTH OF THE INTERSTATE 94/HIGHWAY 10 CORRIDOR. WILL EXPAND
RED FLAG WARNING SOUTH TO INCLUDE THESE AREAS.
STRONG WEST-NORTHWEST WIND WILL APPROACH AND MAY BRIEFLY REACH
WIND ADVISORY THRESHOLDS (SUSTAINED 30 MPH) ACROSS PORTIONS OF
THE DEVILS LAKE BASIN THIS AFTERNOON...BUT WILL HOLD OFF ON
ADDITIONAL HEADLINES GIVEN SHORT DURATION AND MARGINAL WIND
SPEEDS.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE AS HIGH CIRRUS CLOUDS MOVE SLOWLY
OUT OF THE AREA. BIGGER CONCERN FOR THIS AFTERNOON WILL BE WINDS.
WEST WINDS WILL INCREASE DURING THE NEXT FEW HOURS INTO THE 15 TO
25 KT RANGE WITH GUSTS UP ABOVE 30 KTS AT TIMES. THE WINDS WILL
DECREASE AGAIN BELOW 12 KTS AFTER 00Z.
&&
.FIRE WEATHER...
WILL EXPAND RED FLAG WARNING FARTHER SOUTH WITH MORNING UPDATE AND
INCLUDE AREAS ALONG AND NORTH OF THE I-94/HWY 10 CORRIDOR. CRITICAL
FIRE WEATHER CONDITIONS EXPECTED ACROSS THE CENTRAL AND NORTHERN
FORECAST AREA. WEST-NORTHWEST WINDS EXPECTED TO BE ABOVE 20-25
MPH CRITERIA AND HUMIDITIES TO FALL UNDER 25 PERCENT THIS AFTERNOON.
MAY HAVE SOME GUSTS UP 35-40 MPH WITH MIXED LAYER TO 7-10 THOUSAND
FT. NEAR CRITICAL FIRE CONDITIONS WILL BE POSSIBLE OVER THE
REMAINDER OF THE FORECAST AREA WITH LOW HUMIDITIES EXPECTED ACROSS
MUCH OF THE FORECAST AREA.
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT WED SEP 12 2012/
SHORT TERM...TODAY THROUGH FRIDAY NIGHT.
FAIR AMOUNT OF DIFFERENCES BETWEEN THE MODELS BY 84 HOURS. THE GFS
AND GEM WERE THE FAST SOLUTIONS WHILE THE THE NAM THE SLOWEST AND
THE ECMWF A COMPROMISE. WILL PREFER THE ECMWF.
UPPER LEVEL LOW PRESSURE SYSTEM WAS OVER NORTHERN MAN WITH TROUGH
EXTENDING INTO ND. WATER VAPOR LOOP INDICATED WOUND UP SYSTEM OVER
NORTHERN MAN. SECONDARY TROUGH WAS OVER WESTERN MT. SHORT WAVE
FORECAST TO STAY SOUTH AND WEST OF THE AREA. ALSO WATER VAPOR LOOP
INDICATED CIRCULATION CENTER OVER NW ALTA. ALTA SHORT WAVE FORECAST
TO MOVE ACROSS THE FORECAST AREA THU. NO PRECIPITATION IN THE
FORECAST FOR THU. CROSS SECTION INDICATED DRY LAYER UP TO 10
THOUSAND FT. SO WILL NOT ADD ANY POPS FOR NOW.
RADAR SHOWED SPRINKLES/VERY LIGHT SHOWERS OVER FAR SOUTHEAST ZONES
IN RIGHT REAR QUAD OF UPPER LEVEL JET. WILL ADD SPRINKLES IN THE
SOUTHEAST EARLY THIS MORNING.
PRECIPITABLE WATER REMAINS UNDER HALF AN INCH THROUGH 48 HOURS. THEN
A LITTLE ABOVE HALF AN INCH THEREAFTER.
AFTER THU...UPPER RIDGE OVER THE WESTERN US WILL MOVE OVER THE
NORTHERN PLAINS IN A PROGRESSIVE PATTERN.
SURFACE HIGH PRESSURE OVER SOUTHWEST CANADA WILL MOVE INTO THE
WESTERN DAKOTAS THU MORNING. WILL LOWER TEMPS FOR THU MORNING AND
FRI MORNING. HIGH TEMPS TWEAKED NEW COUPLE DAYS.
LONG TERM (SATURDAY-TUESDAY)...
00Z MODEL RUNS CONTINUE TO SHOW THE SAME IDEA AS PREVIOUS RUNS. THE
MAIN FEATURE OF THIS PERIOD WILL BE A COLD FRONT THAT DROPS THROUGH
THE REGION SATURDAY NIGHT OR SUNDAY. EXPECT ABOVE NORMAL
TEMPERATURES AHEAD OF THIS FEATURE...WITH BELOW NORMAL VALUES
BEHIND. AIRMASS REMAINS RELATIVELY DRY...BUT CANNOT RULE OUT
ISOLD/SCATTERED SHOWERS/THUNDER IN FRONTOGENETIC ZONE JUST BEHIND
THE FROPA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR NDZ006>008-
014>016-024-026>030-038-039-054.
MN...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR MNZ001>009-
013>017-022>024-027-028.
&&
$$
ROGERS/HOPPES/JR
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
110 PM CDT WED SEP 12 2012
.DISCUSSION...
18Z TAF UPDATE BELOW.
&&
.AVIATION...
AN ACTIVE MORNING CONVECTION-WISE WILL BE JUST THE BEGINNING OF
THESE PASSING PERIODIC SHOWERS AND OCCASIONAL THUNDERSTORMS
THROUGH THIS PERIOD. THE GREATEST MOISTURE RESIDES JUST OFFSHORE
...POOLING UP OVER THE NEARSHORE WATERS AND IS SCHEDULED TO COME
ONSHORE THROUGH THURSDAY PER WEAK ANTICYCLONIC MID-LEVEL FLOW
PULLS THIS HIGHER MOISTURE NORTHWARD. A DIFFUSE WARM FRONTAL
BOUNDARY WILL CREEP ONSHORE AS WELL AND...WITH THIS ADDITIONAL
(ALONG OR SOUTH OF I-10) LOWER LEVEL FOCUS WITHIN AN MORE TROPICAL
AIR MASS...IT WILL NOT TAKE MUCH TO (RE)INITIATE PRIMARILY SHRA
WITH MID-MORNING THROUGH LATE AFTERNOON TSRA. CONDITIONS WITHIN
ANY MODERATE TO STRONG THUNDERSTORM (+TSRA) WILL LOWER VICINITY
VISBIES DOWN TO AROUND 1-2 SM...LOWER CEILINGS TO MVFR...AND WINDS
WILL QUICKLY BECOME VARIABLE AT 25-30 KTS. 31
&&
.PREV DISCUSSION... /ISSUED 1018 AM CDT WED SEP 12 2012/
DISCUSSION...
13Z SURFACE MAPS SHOWS WEAK CONVERGENCE ALONG THE COAST AND
SCATTERED SHRA/TSRA INCREASING IN COVERAGE OVER THE COASTAL
COUNTIES. 850 MB MOISTURE LOOKS RATHER PLENTIFUL OVER THE EASTERN
HALF OF THE STATE. 700 MB MOISTURE ALSO LOOKS RATHER DEEP FROM
CRP TO LCH. 4 KM WRF AND NMM DON`T SHOW MUCH PRECIP COVERAGE TODAY
WHILE THE LATEST RAP 13 SHOWS GOOD PCPN COVERAGE. 12Z SOUNDINGS
SHOW LOW CONVECTIVE TEMPS...BETWEEN 85 AND 87 DEGREES WITH PW
VALUES BETWEEN 1.8 AND 1.9 INCHES. WEAK CAPPING IS NOTED NEAR 600
MB. WILL LEAN TOWARD THE MORE AGGRESSIVE RAP SINCE THE 12Z
SOUNDINGS LOOK TO BE SUPPORTIVE OF HIGHER RAIN CHANCES. TEMPS LOOK
TO BE ON TRACK ALTHO INCREASED CLOUDS AND RAIN MAY KEEP MAX TEMPS
A LITTLE COOLER. NEW ZONES OUT BY 1030 AM. 43
&&
PREV DISCUSSION... /ISSUED 452 AM CDT WED SEP 12 2012/
DISCUSSION...
STRONG WAA/MOISTURE RETURN HAS BROUGHT SCT SHRA TO THE SRN HALF OF
SE TX LAST NIGHT. THIS PATTERN EXPECTED TO REMAIN IN PLACE FOR THE
NEXT FEW DAYS WITH GULF MOISTURE DEEPENING THROUGHOUT. THIS SHOULD
HELP TO INCREASE POPS BY THE END OF THE WEEK ACROSS OUR FA. ALL OF
THIS SEEMS TO BE A PRELUDE TO A RATHER WET WEEKEND AS A COLD FRONT
AND AN ASSOCIATED COASTAL SFC LOW IN/ACROSS THE REGION. THIS FRONT
FCST TO STALL AT/NEAR THE COAST SAT WITH A LOW PROGGED TO DEVELOP/
FORM ALONG THE BOUNDARY AND MOVE UP THE COAST ON SUN. MODELS ARE A
BIT HINKY WITH THE TIMING OF CLEARING...SO HAVE OPTED TO GO SLOWER
(KEEPING POPS IN THE FCST THRU MON). THE MAIN UNCERTAINTY SEEMS TO
BE HOW WE ARE GOING TO GET PCPN RATHER THAN IF WE ARE GOING TO GET
PCPN. (I.E. ALL SIGNS POINT TO A WET WEEKEND.) 41
MARINE...
WARM FRONT OVER THE COASTAL AREAS EARLY THIS MORNING LIFTING NORTH
TODAY WILL DEEPEN THE MOISTURE ACROSS THE UPPER TEXAS COASTAL
WATERS LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS. CAPE OF
2000-3500 J/KG THIS MORNING WITH A SLIGHTLY BACKED LL FLOW COULD
POSE A THREAT OF TROPICAL FUNNEL CLOUDS ESPECIALLY IN THE AREAS TO
THE EAST OF FREEPORT THROUGH HIGH ISLAND. EASTERLY FLOW DEVELOPING
TONIGHT AND THURSDAY AS HIGH PRESSURE TO THE NORTHEAST STEERS FLOW
WITH A COLD FRONT SLIPPING SOUTH ACROSS THE RED RIVER AND INTO THE
UPPER TEXAS NEARSHORE WATERS SATURDAY AFTERNOON OR SUNDAY
MORNING. GFS/ECMWF DIFFER DRAMATICALLY BY MONDAY AND FAVORING THE
ECMWF SOLUTION WITH A STATIONARY FRONTAL BOUNDARY WITH FRONTAL WAVES
IN THE COASTAL WATERS.
45
AVIATION...
SHORT TERM EXPECT THAT SHOWERS WILL CONTINUE TO DEVELOP IN THE
LEADING EDGE OF THE DEEPER MOISTURE ALONG THE WARM FRONT THIS
MORNING OVER THE HOU-GLS TERMINALS THEN SPREAD INLAND LATE MORNING
AND BEYOND. SOME PATCHY MVFR CIGS POSSIBLE THIS MORNING THOUGH
PRIMARILY ASSOCIATED WITH THE PASSING SHOWERS. VCSH SHOULD COVER IT
FOR NOW WITH TEMPO SHRA CONDITIONS AT LBX/GLS/SGR/HOU BETWEEN 10-
14Z GIVEN THE CURRENT TRENDS ON RADAR. SHOWERS AND THUNDERSTORMS
PROBABILITY INCREASING MID TO LATE MORNING NEAR IAH AND THEN THROUGH
THE AFTERNOON. EASTERLY FLOW THIS MORNING BECOMING SSE AS MOIST FLOW
DEEPENS THEN BACKS OVERNIGHT WITH SCATTERED SHRA/ISO TSRA AGAIN
THURSDAY MORNING.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 91 72 88 70 / 20 40 50 50 40
HOUSTON (IAH) 74 90 72 88 71 / 30 40 40 50 40
GALVESTON (GLS) 79 88 78 87 77 / 30 40 40 50 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1018 AM CDT WED SEP 12 2012
.UPDATE...
SEE MORNING UPDATE.
.DISCUSSION...
13Z SURFACE MAPS SHOWS WEAK CONVERGENCE ALONG THE COAST AND
SCATTERED SHRA/TSRA INCREASING IN COVERAGE OVER THE COASTAL
COUNTIES. 850 MB MOISTURE LOOKS RATHER PLENTIFUL OVER THE EASTERN
HALF OF THE STATE. 700 MB MOISTURE ALSO LOOKS RATHER DEEP FROM
CRP TO LCH. 4 KM WRF AND NMM DON`T SHOW MUCH PRECIP COVERAGE TODAY
WHILE THE LATEST RAP 13 SHOWS GOOD PCPN COVERAGE. 12Z SOUNDINGS
SHOW LOW CONVECTIVE TEMPS...BETWEEN 85 AND 87 DEGREES WITH PW
VALUES BETWEEN 1.8 AND 1.9 INCHES. WEAK CAPPING IS NOTED NEAR 600
MB. WILL LEAN TOWARD THE MORE AGGRESSIVE RAP SINCE THE 12Z
SOUNDINGS LOOK TO BE SUPPORTIVE OF HIGHER RAIN CHANCES. TEMPS LOOK
TO BE ON TRACK ALTHO INCREASED CLOUDS AND RAIN MAY KEEP MAX TEMPS
A LITTLE COOLER. NEW ZONES OUT BY 1030 AM. 43
&&
.PREV DISCUSSION... /ISSUED 452 AM CDT WED SEP 12 2012/
DISCUSSION...
STRONG WAA/MOISTURE RETURN HAS BROUGHT SCT SHRA TO THE SRN HALF OF
SE TX LAST NIGHT. THIS PATTERN EXPECTED TO REMAIN IN PLACE FOR THE
NEXT FEW DAYS WITH GULF MOISTURE DEEPENING THROUGHOUT. THIS SHOULD
HELP TO INCREASE POPS BY THE END OF THE WEEK ACROSS OUR FA. ALL OF
THIS SEEMS TO BE A PRELUDE TO A RATHER WET WEEKEND AS A COLD FRONT
AND AN ASSOCIATED COASTAL SFC LOW IN/ACROSS THE REGION. THIS FRONT
FCST TO STALL AT/NEAR THE COAST SAT WITH A LOW PROGGED TO DEVELOP/
FORM ALONG THE BOUNDARY AND MOVE UP THE COAST ON SUN. MODELS ARE A
BIT HINKY WITH THE TIMING OF CLEARING...SO HAVE OPTED TO GO SLOWER
(KEEPING POPS IN THE FCST THRU MON). THE MAIN UNCERTAINTY SEEMS TO
BE HOW WE ARE GOING TO GET PCPN RATHER THAN IF WE ARE GOING TO GET
PCPN. (I.E. ALL SIGNS POINT TO A WET WEEKEND.) 41
MARINE...
WARM FRONT OVER THE COASTAL AREAS EARLY THIS MORNING LIFTING NORTH
TODAY WILL DEEPEN THE MOISTURE ACROSS THE UPPER TEXAS COASTAL
WATERS LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS. CAPE OF
2000-3500 J/KG THIS MORNING WITH A SLIGHTLY BACKED LL FLOW COULD
POSE A THREAT OF TROPICAL FUNNEL CLOUDS ESPECIALLY IN THE AREAS TO
THE EAST OF FREEPORT THROUGH HIGH ISLAND. EASTERLY FLOW DEVELOPING
TONIGHT AND THURSDAY AS HIGH PRESSURE TO THE NORTHEAST STEERS FLOW
WITH A COLD FRONT SLIPPING SOUTH ACROSS THE RED RIVER AND INTO THE
UPPER TEXAS NEARSHORE WATERS SATURDAY AFTERNOON OR SUNDAY
MORNING. GFS/ECMWF DIFFER DRAMATICALLY BY MONDAY AND FAVORING THE
ECMWF SOLUTION WITH A STATIONARY FRONTAL BOUNDARY WITH FRONTAL WAVES
IN THE COASTAL WATERS.
45
AVIATION...
SHORT TERM EXPECT THAT SHOWERS WILL CONTINUE TO DEVELOP IN THE
LEADING EDGE OF THE DEEPER MOISTURE ALONG THE WARM FRONT THIS
MORNING OVER THE HOU-GLS TERMINALS THEN SPREAD INLAND LATE MORNING
AND BEYOND. SOME PATCHY MVFR CIGS POSSIBLE THIS MORNING THOUGH
PRIMARILY ASSOCIATED WITH THE PASSING SHOWERS. VCSH SHOULD COVER IT
FOR NOW WITH TEMPO SHRA CONDITIONS AT LBX/GLS/SGR/HOU BETWEEN 10-
14Z GIVEN THE CURRENT TRENDS ON RADAR. SHOWERS AND THUNDERSTORMS
PROBABILITY INCREASING MID TO LATE MORNING NEAR IAH AND THEN THROUGH
THE AFTERNOON. EASTERLY FLOW THIS MORNING BECOMING SSE AS MOIST FLOW
DEEPENS THEN BACKS OVERNIGHT WITH SCATTERED SHRA/ISO TSRA AGAIN
THURSDAY MORNING.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 92 74 91 72 88 / 30 20 40 50 50
HOUSTON (IAH) 90 74 90 72 88 / 40 30 40 40 50
GALVESTON (GLS) 88 79 88 78 87 / 40 30 40 40 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
611 PM CDT THU SEP 13 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
313 PM CDT THU SEP 13 2012
MAIN FORECAST CONCERNS ARE FOG IN RIVER VALLEYS AND FROST POTENTIAL
TONIGHT...THEN TEMPERATURES FRIDAY THROUGH SUNDAY.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL LOW OVER
SOUTHERN MANITOBA AND SHORTWAVE TROUGH EMBEDDED IN THE
NORTHWESTERLY FLOW OVER CENTRAL NORTH DAKOTA. LATEST 19Z SURFACE
ANALYSIS INDICATING HIGH PRESSURE BUILDING INTO WESTERN IOWA AND
DRIER AIR BEGINNING TO ADVECT INTO WESTERN FORECAST AREA...WITH
DEWPOINTS FALLING INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS SOUTHERN
AND WESTERN MINNESOTA.
THE 13.12Z GFS/NAM ARE IN DECENT AGREEMENT WITH DEVELOPING ZONAL
FLOW ACROSS THE NORTHERN TIER STATES THIS WEEKEND. THE MOST
SIGNIFICANT DIFFERENCE BETWEEN THE DETERMINISTIC MODELS IS THE NAM
SLIGHTLY FARTHER SOUTH WITH SURFACE FRONT SUNDAY THAN THE GFS. THIS
WOULD PUSH THE MOISTURE CONVERGENCE AND LIFT ALONG THE FRONT INTO THE
NORTHERN FORECAST AREA. HOWEVER...FEEL THE NAM IS TOO FAR SOUTH AND
FOLLOW MORE TOWARDS THE GFS DURING THIS TIMEFRAME.
TONIGHT...THE DETERMINISTIC 13.12Z GFS/NAM AND 13.18Z RAP ARE PICKING
UP WEAK WARM AIR ADVECTION AT 700MB OUT AHEAD OF THE SHORTWAVE TROUGH
OVER CENTRAL NORTH DAKOTA AND PRODUCING MOISTURE IN THE 600-800MB
LAYER PER BUFKIT SOUNDINGS. THE MOISTURE IN THIS LAYER THE
DETERMINISTIC MODELS PROG INTO THE FORECAST AREA AFTER 03Z FRIDAY AND
WILL HAVE IMPACTS ON TEMPERATURES AND FOG POTENTIAL. AT THIS TIME...
UNCERTAINTY EXIST ABOUT FOG DEVELOPMENT IN THE MISSISSIPPI RIVER
VALLEY...AS THE 13.12Z DETERMINISTIC MODELS ARE IN AGREEMENT SOME MID
LEVEL CLOUDS WILL DRIFT OVER THE FORECAST AREA BETWEEN 03Z-09Z
TIMEFRAME. FOR NOW...HAVE KEPT PATCHY TO AREAS FOG IN RIVER VALLEYS.
TEMPERATURES WILL BE AFFECTED BY THE SCATTERED TO BROKEN MID LEVEL
DECK CLOUDS ESPECIALLY OVER SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THE 13.12Z DETERMINISTIC MODELS DISSIPATE MOISTURE/MID CLOUD DECK
OVER WESTERN/CENTRAL WISCONSIN AND TEMPERATURES ARE EXPECTED TO FALL
INTO THE MIDDLE 30S OVER PARTS OF CENTRAL WISCONSIN AND PRODUCE
ISOLATED SPOTS OF PATCHY FROST.
SURFACE RIDGE DOMINATES THE FORECAST AREA FRIDAY INTO SATURDAY
PROVIDING DRY WEATHER CONDITIONS. TEMPERATURES ARE EXPECTED TO
MODERATE AND BE SLIGHTLY ABOVE NORMAL BOTH DAYS...AS THE 13.12Z
DETERMINISTIC MODELS ADVECT SOME WARMER AIR INTO THE AREA.
SURFACE RIDGE BUILDS INTO THE OHIO RIVER VALLEY SATURDAY
NIGHT/SUNDAY AND SOUTHERLY WINDS ON THE BACKSIDE OF THE HIGH PRESSURE
SYSTEM AND ALOFT...WILL USHER IN LOW LEVEL MOISTURE FROM THE
SOUTHERN PLAINS STATES NORTHWARD INTO THE FORECAST AREA. THIS IS
EVIDENT IN THE 850MB TO 925MB RELATIVE HUMIDITY FIELDS PER 13.12Z
GFS/NAM. HAVE INCREASE SKY COVER SLIGHTLY SUNDAY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
313 PM CDT THU SEP 13 2012
MAIN FORECAST CONCERNS THROUGH THE PERIOD ARE PRECIPITATION CHANCES
AND TEMPERATURES. THE 13.12Z GFS/ECMWF/GEM ARE IN ALL PRETTY GOOD
AGREEMENT IN DIGGING UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS AND
THE UPPER GREAT LAKES REGION THROUGH FORECAST PERIOD. BIGGEST
DIFFERENCE BETWEEN THE DETERMINISTIC MODELS IS TIMING OF THE
EMBEDDED SHORTWAVE TROUGHS IN THE NORTHERLY FLOW ALOFT. THIS WILL
HAVE IMPACTS ON TIMING OF PRECIPITATION CHANCES INTO THE FORECAST
AREA THROUGH THE FORECAST PERIOD. THE DETERMINISTIC 13.12Z
GFS/ECMWF/GEM CONTINUE TO SHOW COLDER AIR TO FILTER INTO THE AREA
WITH 850MB TEMPERATURES DROPPING TO AROUND ZERO DEGREES CELSIUS AT
12Z TUESDAY. THE 13.00Z GEFS INDICATE STANDARD ANOMALIES OF MINUS 1
TO MINUS 1.5 OVER THE FORECAST AREA MIDDLE OF NEXT WEEK.
TEMPERATURES WILL BE BELOW NORMAL THROUGH MUCH OF THE FORECAST
PERIOD WITH HIGH TEMPERATURES RISING INTO THE 50S TO 60S.
&&
.AVIATION...TONIGHT AND FRIDAY
611 PM CDT THU SEP 13 2012
THE MAIN CONCERN IS WHETHER VALLEY FOG WILL FORM AT KLSE TONIGHT.
DEW POINTS CRASHED LATE THIS AFTERNOON SETTING UP A TEMP/DEW POINT
SPREAD OF 35 DEGREES. THIS ALONE MAY BE TOO MUCH TO OVERCOME FOR
FOG FORMATION TONIGHT BUT EVEN A MODERATE RECOVERY OF 6 TO 8
DEGREES THIS EVENING WOULD PUT THE DEW POINTS CLOSE TO EXPECTED
OVERNIGHT LOWS. THE OTHER COMPLICATING FACTOR IS THE POSSIBILITY
OF SOME CLOUDS MOVING IN AROUND THE TIME THE FOG STARTS TO FORM.
AN UPPER LEVEL LOW OVER SOUTHWEST ONTARIO IS PUSHING A DECK OF MID
LEVEL CLOUDS SOUTHEAST ACROSS NORTHERN MINNESOTA. IN
ADDITION...OTHER MID LEVEL CLOUDS IN A ZONE OF WARM AIR ADVECTION
AND ISENTROPIC UP GLIDE ON THE 295K SURFACE ARE OVER SOUTHWEST
MINNESOTA. THE 13.18Z NAM SUGGESTS THAT THESE TWO AREAS OF CLOUDS
WILL CONTINUE TO EXPAND/PROPAGATE TOWARD THE AREA OVERNIGHT TO
POINT THAT A HIGH VFR CEILING SHOULD DEVELOP. FOR NOW...HAVE NOT
MADE ANY CHANGES TO THE GOING FORECAST INDICATING THE POSSIBILITY
OF MVFR VISIBILITY RESTRICTIONS IN SOME FOG WITH LOWER VISIBILITY
POSSIBLE AROUND KLSE BUT WILL MONITOR THE DEW POINTS AND CLOUDS
THROUGH THE EVENING FOR ADJUSTMENTS WITH THE 06Z TAF. OUTSIDE OF
THE FOG...VFR CONDITIONS WILL PREVAIL THROUGH FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
313 PM CDT THU SEP 13 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....DTJ
LONG TERM......DTJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1241 PM CDT WED SEP 12 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
339 AM CDT WED SEP 12 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION AND TEMPERATURE TRENDS
THROUGH THURSDAY...THEN POTENTIAL FOR VALLEY FOG AND PATCHY FROST
THURSDAY NIGHT INTO FRIDAY MORNING.
AS OF 08Z WEDNESDAY...WATER VAPOR IMAGERY AND RAP 500MB HEIGHT
FIELDS DEPICT A LARGE TROUGH ACROSS SOUTHERN CANADA INTO THE
NORTHERN PLAINS WHILE A LARGE RIDGE OF HIGH PRESSURE WAS CENTERED
ACROSS THE SOUTHEAST US. IN-BETWEEN...A PLUME OF SOUTHWEST MONSOONAL
MOISTURE WAS BEING ADVECTED NORTHEAST TOWARDS THE FORECAST AREA
WHERE PRECIPITABLE WATER VALUES RANGED FROM 0.75 TO 1.1 INCHES / 80
TO 120 PERCENT OF NORMAL / PER GOES SOUNDER IMAGERY. A 250MB JET
STREAK WAS NOTED ACROSS NORTHERN NORTH DAKOTA INTO EXTREME SOUTHWEST
ONTARIO. AT THE SURFACE...A COLD FRONT STRETCHED FROM NORTHWEST
WISCONSIN TO THE TWIN CITIES TO OMAHA NEBRASKA WHERE COMBINED WITH
INCREASING 850 MB TRANSPORT AHEAD OF THE FRONT AND MID TO UPPER
LEVEL FRONTOGENETICAL SUPPORT WAS GENERATING POST FRONTAL SHOWERS.
MEANWHILE...SOME WARM AIR ADVECTION SHOWERS AHEAD AND ALONG THE
FRONT WERE DEVELOPING ACROSS NORTHERN IOWA INTO SOUTHERN MINNESOTA.
DEWPOINT DEPRESSIONS REMAINED 25 TO 30F BUT A FEW SITES WERE
REPORTING PRECIPITATION UNDER 8 TO 10 KFT CLOUD BASES. LATEST IR
IMAGERY SHOWS HIGH CLOUDS ACROSS MUCH OF THE FORECAST AREA.
TODAY AND TONIGHT...EXCELLENT AGREEMENT BETWEEN THE LATEST
NAM/GFS/ECMWF/SREF/RAP DEPICTING THE COLD FRONT MAKING A STEADY
PROGRESS SOUTHEAST THROUGH THE FORECAST AREA SUCH THAT BY 12Z IT
SHOULD BE ALONG A BLACK RIVER FALLS TO LA CROSSE WISCONSIN TO
CHARLES CITY IOWA LINE. TEMPERATURES ARE TRICKY WITH CONTINUED
SOUTHWEST FLOW EXPECTED AHEAD OF THE FRONT WHERE LOCATIONS IN
NORTHEAST IOWA AND EXTREME SOUTHWEST WISCONSIN SHOULD REMAIN IN WARM
SECTOR FOR MUCH OF THE DAY...TOPPING OUT IN THE LOWER TO MIDDLE
80S. NON-DIURNAL TREND ON TRACK FOR OTHER SPOTS WHERE HIGHS SHOULD
OCCUR AROUND 18Z...FALLING INTO THE MIDDLE 60S BY 21Z. AS DEWPOINTS
CRASH INTO THE UPPER 40S LATE THIS AFTERNOON AND PRECIPITATION
BEGINS...TEMPERATURES LOOK TO QUICKLY DROP OFF.
DYNAMICS LOOK GOOD WITH FORECAST AREA FAVORABLY POSITIONED IN THE
RIGHT ENTRANCE REGION OF THE 250MB JET. A NW-SE CROSS SECTION
THROUGH THE REGION SHOWS STRONG FRONTOGENETICAL BAND WITH IDEAL
FRONTOLYSIS/FRONTOGENETICAL CIRCULATION SETTING UP ACROSS THE AREA
BEGINNING THIS EVENING. STRONG ISENTROPIC UPGLIDE ON THE 305-315K
SURFACES IS PRESENT ALONG WITH DECENT 850 MB MOISTURE TRANSPORT.
DESPITE SOME LOW LEVEL DRY AIR CONCERNS INITIALLY...THAT SHOULD BE
OVERCOME SUCH THAT SHOWERS WILL DEVELOP / MOVE INTO SOUTHEAST
MINNESOTA AND WESTERN WISCONSIN BETWEEN 22-00Z...THEN SAG SOUTHEAST
THROUGH THE NIGHT. THE LATEST MESO MODELS ARE IN GOOD AGREEMENT WITH
THIS SCENARIO AS WELL. REGARDING RAINFALL TOTALS THROUGH THE
EVENT...A NORTH/SOUTH GRADIENT SHOULD SET UP AS BETTER FORCING/LIFT
ACROSS IOWA INTO SOUTHERN WISCONSIN. TOTALS AROUND 1/10 OF AN INCH
ACROSS NORTH CENTRAL WISCONSIN....TO 1/3 TO 1/2 ALONG THE I-90
CORRIDOR...THE UPWARDS OF 3/4 OF AN INCH LOOK PROMISING FOR THE
AREA.
THURSDAY AND FRIDAY...BY 12Z THURSDAY...THE BULK OF THE
PRECIPITATION SHOULD BE ORIENTED THROUGH CENTRAL WISCONSIN TO
NORTHEAST IOWA. TIMING THE PROGRESS OF THIS PRECIPITATION OUT OF THE
FORECAST AREA IS A BIT TRICKY. THIS IS MOST LIKELY DUE TO MODEL
TIMING DIFFERENCES INCREASING ON HOW THE NEXT SHORTWAVE...CURRENTLY
IN NORTHWEST ALBERTA...DIVING SOUTHEAST DURING THE DAY THURSDAY IS
HANDLED. THE 12.00Z NAM IS A SLOWER OUTLIER...WHILE THE 12.00Z
GFS/CANADIAN/ECMWF ARE IN GOOD AGREEMENT. HAVE DISCOUNTED THE NAM
FOR THE TIME BEING...GIVEN TRENDS OVER THE PAST DAY TO BE FASTER.
THE HIGHEST PRECIPITATION CHANCES AFTER 15Z THURSDAY LOOK TO BE
SOUTH/EAST OF A SPARTA WISCONSIN TO OELWEIN IOWA LINE. A COOL DAY ON
TAP FOR THE AREA WITH MOSTLY CLOUDY TO CLOUDY SKIES UNDER COLD AIR
ADVECTION AND 850MB TEMPS PROGGED TO BE 5-8C. AREAS SOUTH/EAST WILL
BE THE COOLEST WITH MORE CLOUDS/RAIN...AND PROBABLY WILL ONLY MAKE
IT TO 60F AT BEST. AS THE NORTHWEST ALBERTA SHORTWAVE DIVES THROUGH
MINNESOTA DURING THE AFTERNOON AND COMBINES WITH DIURNAL
HEATING...SCATTERED SHOWERS ARE POSSIBLE...MAINLY CONFINED TO THE
NORTHWEST AREAS. STEEPER LAPSE RATES AND MAYBE SOME INSTABILITY TO
WORK WITH COULD PRODUCE A RUMBLE OR TWO OF THUNDER AS WELL.
THE NORTHWEST ALBERTA SHORTWAVE QUICKLY PIVOTS THROUGH THE NORTHERN
PLAINS LATE THURSDAY AND BY 06Z FRIDAY SHOULD BE CENTERED ACROSS
WISCONSIN. AT THE SURFACE...BUILDING CANADIAN HIGH PRESSURE THURSDAY
NIGHT INTO FRIDAY MORNING WILL BRING SOME OF THE COLDEST AIR OF THE
AUTUMN SEASON THUS FAR. THE COMBINATION OF PRECIPITABLE WATER VALUES
DROPPING TO A 0.5 INCH OR LESS...DIMINISHING WINDS WITH THE HIGH
PRESSURE AREA BUILDING IN AND CLEARING SKIES WILL ALL HELP
TEMPERATURES TO TANK. LOWS LOOK TO DROP DOWN TO THE LOWER 40S TO
AROUND 40 FOR MOST LOCATIONS. ALONG AND NORTHEAST OF THE I-94
CORRIDOR IN WISCONSIN...THE TYPICAL COLD SPOTS COULD EVEN SEE SOME
PATCHY FROST...THOUGH THIS WOULD ALL HINGE ON THE SURFACE HIGH
POSITION. RIVER VALLEY FOG WOULD ALSO BE A CONCERN GIVEN THIS
SYNOPTIC SETUP...ESPECIALLY GIVEN EXPECTED RAINFALL OVER THE NEXT 36
HOURS AND THE COOLER AND CLOUDIER DAY EXPECTED THURSDAY. RIGHT NOW
THE GFS IS A FASTER OUTLIER IN BRINGING IN THE SURFACE HIGH...MAKING
ITS SOLUTION THE MOST FAVORABLE FOR WIDESPREAD VALLEY FOG AND ALSO
MORNING FROST ACROSS NORTH CENTRAL WISCONSIN. DEFINITELY SOMETHING
TO WATCH CLOSELY IN THE NEXT FORECAST RUNS. FOR NOW HAVE ONLY
INCLUDED AREAS OF FOG FOR THE WISCONSIN RIVER AND ITS TRIBUTARIES...
AND PATCHY FOG FOR THE MISSISSIPPI RIVER. FRIDAY LOOKS TO BE A VERY
PLEASANT DAY FOR THE ENTIRE UPPER MIDWEST WITH THE HIGH PRESSURE
DRIFTING OVERHEAD...PROVIDING LIGHT WINDS. 850MB TEMPS OF 6-8C AND
PLENTY OF SUN SHOULD RESULT IN HIGHS SLIGHTLY BELOW NORMAL...IN THE
UPPER 60S TO LOWER 70S.
QUIET WEATHER LOOKS TO PERSIST INTO FRIDAY NIGHT WITH THE HIGH
PRESSURE REMAINING NEARBY. LOW PRECIPITABLE WATER VALUES ARE STILL
SUGGESTED...SO ANOTHER COOL NIGHT IS EXPECTED WITH LOWS IN THE UPPER
30S AT THE TYPICAL COLD SPOTS AND LOW TO MID 40S ELSEWHERE. MAY
AGAIN BE DEALING WITH VALLEY FOG AND FROST.
.LONG TERM...SATURDAY THROUGH TUESDAY NIGHT
339 AM CDT WED SEP 12 2012
12.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE IN MUCH BETTER
AGREEMENT ON THE UPPER LEVEL PATTERN COMPARED TO THE PAST FEW DAYS
FOR THE LONG TERM FORECAST. THERE STILL ARE SOME ISSUES...MOSTLY
IMPACTING TUESDAY AND TUESDAY NIGHT.
TO BEGIN THE LONG TERM FORECAST...NEARLY ZONAL FLOW EXISTS WITH THE
WESTERLIES RUNNING ACROSS SOUTHERN CANADA. WITHIN THIS FLOW...
THOUGH...THERE IS A POTENT SHORTWAVE CROSSING NORTHERN SASKATCHEWAN
WITH INDICATIONS OF TROUGHING BEGINNING TO FORM OVER WESTERN
ALBERTA. THIS TROUGHING ENDS UP DEEPENING ACROSS CENTRAL CANADA BY
LATE SUNDAY DUE TO RIDGING BUILDING UP INTO BRITISH COLUMBIA. AHEAD
OF THIS UPPER TROUGHING AND ASSOCIATED WITH THAT POTENT SHORTWAVE...
MODELS DEPICT A COLD FRONT. THIS FRONT LOOKS TO CROSS THE FORECAST
AREA SUNDAY NIGHT AT THE PRESENT TIME...WHICH IS WHEN THE TROUGHING
BEGINS TO DIG DOWN INTO THE NORTH CENTRAL U.S.. ANTICIPATING DRY
WEATHER UNTIL THIS FRONT PASSES...DUE TO THE DRY AIRMASS AHEAD OF
IT. WITH 850MB TEMPS RUNNING AROUND 8C ON SATURDAY AND 10-12C ON
SUNDAY...HIGH TEMPERATURES BOTH DAYS SHOULD BE ABLE TO TOP OUT IN
THE 70S. CHANGES ARE DEFINITELY ON THE WAY FOR MONDAY...THOUGH...AS
THE UPPER TROUGH APPROACHES THE AREA. LIKE TODAY THROUGH THURSDAY...
INDICATIONS ARE THAT A FRONTOGENETIC BAND OF PRECIPITATION WILL FORM
BEHIND THE COLD FRONT. HOW MUCH PRECIPITATION FORMS DEPENDS ON HOW
MUCH THE UPPER TROUGHING DIGS DOWN INTO THE NORTH CENTRAL U.S....
WHICH IS A LITTLE UNCERTAIN AT THIS TIME. THEREFORE...WILL BE
FOLLOWING THE CONSENSUS PRECIPITATION CHANCES OF 30-40 FOR MONDAY
AND MONDAY NIGHT. IF MODEL TRENDS CONTINUE...CHANCES ARE LIKELY
GOING TO BE RAISED IN LATER FORECASTS FOR MONDAY AND MONDAY NIGHT.
THE FORECAST FOR TUESDAY AND TUESDAY NIGHT ALSO RELY ON WHAT HAPPENS
WITH THE NORTH CENTRAL U.S. TROUGH. THE 12.00Z GFS FORMS A CLOSED
UPPER LOW OVER THE FORECAST AREA WHILE THE 11.12Z/12.00Z ECMWF KEEP
THE TROUGH PROGRESSIVE. THE FORMER SCENARIO YIELDS WET WHILE THE
LATTER SCENARIO SUGGESTS DRY...THOUGH BOTH ARE COOL AS 850MB TEMPS
TUMBLE TO A CHILLY 0-2C. 12.00Z GFS ENSEMBLES SUGGESTS BOTH THE GFS
AND ECMWF ARE POSSIBLE...THEREFORE 20-30 PERCENT CHANCES OF
PRECIPITATION ARE IN THE FORECAST. HIGHS TUESDAY WILL BE AT LEAST 15
DEGREES COLDER THAN THOSE ON SUNDAY...IF NOT MORE.
&&
.AVIATION...THROUGH 18Z THURSDAY
1241 PM CDT WED SEP 12 2012
THE MAIN FOCUS AT THE TAF SITES IS WITH THE OCCASIONAL RAIN
SHOWERS THROUGH TONIGHT ALONG WITH THE POTENTIAL FOR MVFR CEILINGS
THROUGH TONIGHT AND GUSTY WINDS THIS AFTERNOON. A COLD FRONT HAS
MOVED THROUGH LSE AND RST THIS MORNING LEAVING NORTHERLY WINDS IN
ITS WAKE. SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE IN
FROM THE WEST THROUGH THE AFTERNOON AND EVENING HOURS AND BECOME
MORE WIDESPREAD AS THE DAY GOES ON. DUE TO DRY AIR IN THE LOW
LEVELS...VISIBILITY HAS BEEN GREATER THAN 6SM THROUGHOUT THE
REGION WITH CEILINGS HIGH AS WELL IN THE 6-10KFT RANGE. FORECAST
SOUNDINGS FOR RST AND LSE INDICATE THE SAME SHOULD HOLD ON FOR
TONIGHT...SO HAVE NOT PUT ANY MVFR INTO THE TAFS. FORECAST
GUIDANCE IS ALSO SUGGESTING THAT WINDS WILL RAPIDLY INCREASE THIS
AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS ON THE NORTHERN SIDE
OF THE COLD FRONT. CONFIDENCE IS NOT HIGH WITH HOW HIGH THE GUSTS
WILL GET...SO HAVE AT LEAST STARTED A TREND TOWARD HIGHER WINDS
WITH GUSTS OF AROUND 25KT OCCURRING THIS AFTERNOON AND EARLY
EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
339 AM CDT WED SEP 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT WED SEP 12 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
339 AM CDT WED SEP 12 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION AND TEMPERATURE TRENDS
THROUGH THURSDAY...THEN POTENTIAL FOR VALLEY FOG AND PATCHY FROST
THURSDAY NIGHT INTO FRIDAY MORNING.
AS OF 08Z WEDNESDAY...WATER VAPOR IMAGERY AND RAP 500MB HEIGHT
FIELDS DEPICT A LARGE TROUGH ACROSS SOUTHERN CANADA INTO THE
NORTHERN PLAINS WHILE A LARGE RIDGE OF HIGH PRESSURE WAS CENTERED
ACROSS THE SOUTHEAST US. IN-BETWEEN...A PLUME OF SOUTHWEST MONSOONAL
MOISTURE WAS BEING ADVECTED NORTHEAST TOWARDS THE FORECAST AREA
WHERE PRECIPITABLE WATER VALUES RANGED FROM 0.75 TO 1.1 INCHES / 80
TO 120 PERCENT OF NORMAL / PER GOES SOUNDER IMAGERY. A 250MB JET
STREAK WAS NOTED ACROSS NORTHERN NORTH DAKOTA INTO EXTREME SOUTHWEST
ONTARIO. AT THE SURFACE...A COLD FRONT STRETCHED FROM NORTHWEST
WISCONSIN TO THE TWIN CITIES TO OMAHA NEBRASKA WHERE COMBINED WITH
INCREASING 850 MB TRANSPORT AHEAD OF THE FRONT AND MID TO UPPER
LEVEL FRONTOGENETICAL SUPPORT WAS GENERATING POST FRONTAL SHOWERS.
MEANWHILE...SOME WARM AIR ADVECTION SHOWERS AHEAD AND ALONG THE
FRONT WERE DEVELOPING ACROSS NORTHERN IOWA INTO SOUTHERN MINNESOTA.
DEWPOINT DEPRESSIONS REMAINED 25 TO 30F BUT A FEW SITES WERE
REPORTING PRECIPITATION UNDER 8 TO 10 KFT CLOUD BASES. LATEST IR
IMAGERY SHOWS HIGH CLOUDS ACROSS MUCH OF THE FORECAST AREA.
TODAY AND TONIGHT...EXCELLENT AGREEMENT BETWEEN THE LATEST
NAM/GFS/ECMWF/SREF/RAP DEPICTING THE COLD FRONT MAKING A STEADY
PROGRESS SOUTHEAST THROUGH THE FORECAST AREA SUCH THAT BY 12Z IT
SHOULD BE ALONG A BLACK RIVER FALLS TO LA CROSSE WISCONSIN TO
CHARLES CITY IOWA LINE. TEMPERATURES ARE TRICKY WITH CONTINUED
SOUTHWEST FLOW EXPECTED AHEAD OF THE FRONT WHERE LOCATIONS IN
NORTHEAST IOWA AND EXTREME SOUTHWEST WISCONSIN SHOULD REMAIN IN WARM
SECTOR FOR MUCH OF THE DAY...TOPPING OUT IN THE LOWER TO MIDDLE
80S. NON-DIURNAL TREND ON TRACK FOR OTHER SPOTS WHERE HIGHS SHOULD
OCCUR AROUND 18Z...FALLING INTO THE MIDDLE 60S BY 21Z. AS DEWPOINTS
CRASH INTO THE UPPER 40S LATE THIS AFTERNOON AND PRECIPITATION
BEGINS...TEMPERATURES LOOK TO QUICKLY DROP OFF.
DYNAMICS LOOK GOOD WITH FORECAST AREA FAVORABLY POSITIONED IN THE
RIGHT ENTRANCE REGION OF THE 250MB JET. A NW-SE CROSS SECTION
THROUGH THE REGION SHOWS STRONG FRONTOGENETICAL BAND WITH IDEAL
FRONTOLYSIS/FRONTOGENETICAL CIRCULATION SETTING UP ACROSS THE AREA
BEGINNING THIS EVENING. STRONG ISENTROPIC UPGLIDE ON THE 305-315K
SURFACES IS PRESENT ALONG WITH DECENT 850 MB MOISTURE TRANSPORT.
DESPITE SOME LOW LEVEL DRY AIR CONCERNS INITIALLY...THAT SHOULD BE
OVERCOME SUCH THAT SHOWERS WILL DEVELOP / MOVE INTO SOUTHEAST
MINNESOTA AND WESTERN WISCONSIN BETWEEN 22-00Z...THEN SAG SOUTHEAST
THROUGH THE NIGHT. THE LATEST MESO MODELS ARE IN GOOD AGREEMENT WITH
THIS SCENARIO AS WELL. REGARDING RAINFALL TOTALS THROUGH THE
EVENT...A NORTH/SOUTH GRADIENT SHOULD SET UP AS BETTER FORCING/LIFT
ACROSS IOWA INTO SOUTHERN WISCONSIN. TOTALS AROUND 1/10 OF AN INCH
ACROSS NORTH CENTRAL WISCONSIN....TO 1/3 TO 1/2 ALONG THE I-90
CORRIDOR...THE UPWARDS OF 3/4 OF AN INCH LOOK PROMISING FOR THE
AREA.
THURSDAY AND FRIDAY...BY 12Z THURSDAY...THE BULK OF THE
PRECIPITATION SHOULD BE ORIENTED THROUGH CENTRAL WISCONSIN TO
NORTHEAST IOWA. TIMING THE PROGRESS OF THIS PRECIPITATION OUT OF THE
FORECAST AREA IS A BIT TRICKY. THIS IS MOST LIKELY DUE TO MODEL
TIMING DIFFERENCES INCREASING ON HOW THE NEXT SHORTWAVE...CURRENTLY
IN NORTHWEST ALBERTA...DIVING SOUTHEAST DURING THE DAY THURSDAY IS
HANDLED. THE 12.00Z NAM IS A SLOWER OUTLIER...WHILE THE 12.00Z
GFS/CANADIAN/ECMWF ARE IN GOOD AGREEMENT. HAVE DISCOUNTED THE NAM
FOR THE TIME BEING...GIVEN TRENDS OVER THE PAST DAY TO BE FASTER.
THE HIGHEST PRECIPITATION CHANCES AFTER 15Z THURSDAY LOOK TO BE
SOUTH/EAST OF A SPARTA WISCONSIN TO OELWEIN IOWA LINE. A COOL DAY ON
TAP FOR THE AREA WITH MOSTLY CLOUDY TO CLOUDY SKIES UNDER COLD AIR
ADVECTION AND 850MB TEMPS PROGGED TO BE 5-8C. AREAS SOUTH/EAST WILL
BE THE COOLEST WITH MORE CLOUDS/RAIN...AND PROBABLY WILL ONLY MAKE
IT TO 60F AT BEST. AS THE NORTHWEST ALBERTA SHORTWAVE DIVES THROUGH
MINNESOTA DURING THE AFTERNOON AND COMBINES WITH DIURNAL
HEATING...SCATTERED SHOWERS ARE POSSIBLE...MAINLY CONFINED TO THE
NORTHWEST AREAS. STEEPER LAPSE RATES AND MAYBE SOME INSTABILITY TO
WORK WITH COULD PRODUCE A RUMBLE OR TWO OF THUNDER AS WELL.
THE NORTHWEST ALBERTA SHORTWAVE QUICKLY PIVOTS THROUGH THE NORTHERN
PLAINS LATE THURSDAY AND BY 06Z FRIDAY SHOULD BE CENTERED ACROSS
WISCONSIN. AT THE SURFACE...BUILDING CANADIAN HIGH PRESSURE THURSDAY
NIGHT INTO FRIDAY MORNING WILL BRING SOME OF THE COLDEST AIR OF THE
AUTUMN SEASON THUS FAR. THE COMBINATION OF PRECIPITABLE WATER VALUES
DROPPING TO A 0.5 INCH OR LESS...DIMINISHING WINDS WITH THE HIGH
PRESSURE AREA BUILDING IN AND CLEARING SKIES WILL ALL HELP
TEMPERATURES TO TANK. LOWS LOOK TO DROP DOWN TO THE LOWER 40S TO
AROUND 40 FOR MOST LOCATIONS. ALONG AND NORTHEAST OF THE I-94
CORRIDOR IN WISCONSIN...THE TYPICAL COLD SPOTS COULD EVEN SEE SOME
PATCHY FROST...THOUGH THIS WOULD ALL HINGE ON THE SURFACE HIGH
POSITION. RIVER VALLEY FOG WOULD ALSO BE A CONCERN GIVEN THIS
SYNOPTIC SETUP...ESPECIALLY GIVEN EXPECTED RAINFALL OVER THE NEXT 36
HOURS AND THE COOLER AND CLOUDIER DAY EXPECTED THURSDAY. RIGHT NOW
THE GFS IS A FASTER OUTLIER IN BRINGING IN THE SURFACE HIGH...MAKING
ITS SOLUTION THE MOST FAVORABLE FOR WIDESPREAD VALLEY FOG AND ALSO
MORNING FROST ACROSS NORTH CENTRAL WISCONSIN. DEFINITELY SOMETHING
TO WATCH CLOSELY IN THE NEXT FORECAST RUNS. FOR NOW HAVE ONLY
INCLUDED AREAS OF FOG FOR THE WISCONSIN RIVER AND ITS TRIBUTARIES...
AND PATCHY FOG FOR THE MISSISSIPPI RIVER. FRIDAY LOOKS TO BE A VERY
PLEASANT DAY FOR THE ENTIRE UPPER MIDWEST WITH THE HIGH PRESSURE
DRIFTING OVERHEAD...PROVIDING LIGHT WINDS. 850MB TEMPS OF 6-8C AND
PLENTY OF SUN SHOULD RESULT IN HIGHS SLIGHTLY BELOW NORMAL...IN THE
UPPER 60S TO LOWER 70S.
QUIET WEATHER LOOKS TO PERSIST INTO FRIDAY NIGHT WITH THE HIGH
PRESSURE REMAINING NEARBY. LOW PRECIPITABLE WATER VALUES ARE STILL
SUGGESTED...SO ANOTHER COOL NIGHT IS EXPECTED WITH LOWS IN THE UPPER
30S AT THE TYPICAL COLD SPOTS AND LOW TO MID 40S ELSEWHERE. MAY
AGAIN BE DEALING WITH VALLEY FOG AND FROST.
.LONG TERM...SATURDAY THROUGH TUESDAY NIGHT
339 AM CDT WED SEP 12 2012
12.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE IN MUCH BETTER
AGREEMENT ON THE UPPER LEVEL PATTERN COMPARED TO THE PAST FEW DAYS
FOR THE LONG TERM FORECAST. THERE STILL ARE SOME ISSUES...MOSTLY
IMPACTING TUESDAY AND TUESDAY NIGHT.
TO BEGIN THE LONG TERM FORECAST...NEARLY ZONAL FLOW EXISTS WITH THE
WESTERLIES RUNNING ACROSS SOUTHERN CANADA. WITHIN THIS FLOW...
THOUGH...THERE IS A POTENT SHORTWAVE CROSSING NORTHERN SASKATCHEWAN
WITH INDICATIONS OF TROUGHING BEGINNING TO FORM OVER WESTERN
ALBERTA. THIS TROUGHING ENDS UP DEEPENING ACROSS CENTRAL CANADA BY
LATE SUNDAY DUE TO RIDGING BUILDING UP INTO BRITISH COLUMBIA. AHEAD
OF THIS UPPER TROUGHING AND ASSOCIATED WITH THAT POTENT SHORTWAVE...
MODELS DEPICT A COLD FRONT. THIS FRONT LOOKS TO CROSS THE FORECAST
AREA SUNDAY NIGHT AT THE PRESENT TIME...WHICH IS WHEN THE TROUGHING
BEGINS TO DIG DOWN INTO THE NORTH CENTRAL U.S.. ANTICIPATING DRY
WEATHER UNTIL THIS FRONT PASSES...DUE TO THE DRY AIRMASS AHEAD OF
IT. WITH 850MB TEMPS RUNNING AROUND 8C ON SATURDAY AND 10-12C ON
SUNDAY...HIGH TEMPERATURES BOTH DAYS SHOULD BE ABLE TO TOP OUT IN
THE 70S. CHANGES ARE DEFINITELY ON THE WAY FOR MONDAY...THOUGH...AS
THE UPPER TROUGH APPROACHES THE AREA. LIKE TODAY THROUGH THURSDAY...
INDICATIONS ARE THAT A FRONTOGENETIC BAND OF PRECIPITATION WILL FORM
BEHIND THE COLD FRONT. HOW MUCH PRECIPITATION FORMS DEPENDS ON HOW
MUCH THE UPPER TROUGHING DIGS DOWN INTO THE NORTH CENTRAL U.S....
WHICH IS A LITTLE UNCERTAIN AT THIS TIME. THEREFORE...WILL BE
FOLLOWING THE CONSENSUS PRECIPITATION CHANCES OF 30-40 FOR MONDAY
AND MONDAY NIGHT. IF MODEL TRENDS CONTINUE...CHANCES ARE LIKELY
GOING TO BE RAISED IN LATER FORECASTS FOR MONDAY AND MONDAY NIGHT.
THE FORECAST FOR TUESDAY AND TUESDAY NIGHT ALSO RELY ON WHAT HAPPENS
WITH THE NORTH CENTRAL U.S. TROUGH. THE 12.00Z GFS FORMS A CLOSED
UPPER LOW OVER THE FORECAST AREA WHILE THE 11.12Z/12.00Z ECMWF KEEP
THE TROUGH PROGRESSIVE. THE FORMER SCENARIO YIELDS WET WHILE THE
LATTER SCENARIO SUGGESTS DRY...THOUGH BOTH ARE COOL AS 850MB TEMPS
TUMBLE TO A CHILLY 0-2C. 12.00Z GFS ENSEMBLES SUGGESTS BOTH THE GFS
AND ECMWF ARE POSSIBLE...THEREFORE 20-30 PERCENT CHANCES OF
PRECIPITATION ARE IN THE FORECAST. HIGHS TUESDAY WILL BE AT LEAST 15
DEGREES COLDER THAN THOSE ON SUNDAY...IF NOT MORE.
&&
.AVIATION...THROUGH 12Z THURSDAY
630 AM CDT WED SEP 12 2012
A COLD FRONT WILL CONTINUE TO MOVE SOUTHEAST ACROSS THE AREA THIS
MORNING. THE FRONT PASSED KRST AROUND 11Z AND SHOULD PASS KLSE BY
15Z. FORCING/LIFT AND MOISTURE TRANSPORT OVER THIS FRONT WAS
PRODUCING A BROAD BAND OF -RA/-SHRA FROM EASTERN NEB TO FAR
NORTHWEST WI. CIGS/VSBYS IN THE PRECIP EARLY THIS MORNING WERE
GENERALLY 8-10K FT AND 10SM. WITH THE FRONT MOVING SLOWLY ACROSS THE
AREA TODAY...A PROLONGED PERIOD OF THE POST-FRONTAL FORCING/LIFT AND
MOISTURE TRANSPORT IS EXPECTED OVER THE TAF SITES. THIS LEADS TO
LONGER PERIODS OF VCSH OR -SHRA IN THE TAFS...BUT CONDITIONS LOOK TO
REMAIN MOSTLY VFR AS THE MAIN FORCING/LIFT IS ABOVE 850MB AND THE
SFC-850MB FLOW BEHIND THE FRONT IS DRIER AND FROM THE NORTH. DID ADD
A PERIOD OF 6SM -SHRA TO BOTH KRST/KLSE LATER THIS AFTERNOON/
EVENING...WHEN THE STRONGEST/DEEPEST OF THE FORCING/LIFT IS EXPECTED
TO TRANSLATE ACROSS THE TAF SITES AND PRODUCE A PERIOD OF MODERATE
RA/SHRA. CONDITIONS IMPROVE TO GOOD VFR LATER TONIGHT AS THE BAND OF
-SHRA/-RA SINKS SOUTH OF THE AREA AND DEEPER/DRIER AIR IN THE
SFC-700MB LAYER SPREADS INTO THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
339 AM CDT WED SEP 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
339 AM CDT WED SEP 12 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
339 AM CDT WED SEP 12 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION AND TEMPERATURE TRENDS
THROUGH THURSDAY...THEN POTENTIAL FOR VALLEY FOG AND PATCHY FROST
THURSDAY NIGHT INTO FRIDAY MORNING.
AS OF 08Z WEDNESDAY...WATER VAPOR IMAGERY AND RAP 500MB HEIGHT
FIELDS DEPICT A LARGE TROUGH ACROSS SOUTHERN CANADA INTO THE
NORTHERN PLAINS WHILE A LARGE RIDGE OF HIGH PRESSURE WAS CENTERED
ACROSS THE SOUTHEAST US. IN-BETWEEN...A PLUME OF SOUTHWEST MONSOONAL
MOISTURE WAS BEING ADVECTED NORTHEAST TOWARDS THE FORECAST AREA
WHERE PRECIPITABLE WATER VALUES RANGED FROM 0.75 TO 1.1 INCHES / 80
TO 120 PERCENT OF NORMAL / PER GOES SOUNDER IMAGERY. A 250MB JET
STREAK WAS NOTED ACROSS NORTHERN NORTH DAKOTA INTO EXTREME SOUTHWEST
ONTARIO. AT THE SURFACE...A COLD FRONT STRETCHED FROM NORTHWEST
WISCONSIN TO THE TWIN CITIES TO OMAHA NEBRASKA WHERE COMBINED WITH
INCREASING 850 MB TRANSPORT AHEAD OF THE FRONT AND MID TO UPPER
LEVEL FRONTOGENETICAL SUPPORT WAS GENERATING POST FRONTAL SHOWERS.
MEANWHILE...SOME WARM AIR ADVECTION SHOWERS AHEAD AND ALONG THE
FRONT WERE DEVELOPING ACROSS NORTHERN IOWA INTO SOUTHERN MINNESOTA.
DEWPOINT DEPRESSIONS REMAINED 25 TO 30F BUT A FEW SITES WERE
REPORTING PRECIPITATION UNDER 8 TO 10 KFT CLOUD BASES. LATEST IR
IMAGERY SHOWS HIGH CLOUDS ACROSS MUCH OF THE FORECAST AREA.
TODAY AND TONIGHT...EXCELLENT AGREEMENT BETWEEN THE LATEST
NAM/GFS/ECMWF/SREF/RAP DEPICTING THE COLD FRONT MAKING A STEADY
PROGRESS SOUTHEAST THROUGH THE FORECAST AREA SUCH THAT BY 12Z IT
SHOULD BE ALONG A BLACK RIVER FALLS TO LA CROSSE WISCONSIN TO
CHARLES CITY IOWA LINE. TEMPERATURES ARE TRICKY WITH CONTINUED
SOUTHWEST FLOW EXPECTED AHEAD OF THE FRONT WHERE LOCATIONS IN
NORTHEAST IOWA AND EXTREME SOUTHWEST WISCONSIN SHOULD REMAIN IN WARM
SECTOR FOR MUCH OF THE DAY...TOPPING OUT IN THE LOWER TO MIDDLE
80S. NON-DIURNAL TREND ON TRACK FOR OTHER SPOTS WHERE HIGHS SHOULD
OCCUR AROUND 18Z...FALLING INTO THE MIDDLE 60S BY 21Z. AS DEWPOINTS
CRASH INTO THE UPPER 40S LATE THIS AFTERNOON AND PRECIPITATION
BEGINS...TEMPERATURES LOOK TO QUICKLY DROP OFF.
DYNAMICS LOOK GOOD WITH FORECAST AREA FAVORABLY POSITIONED IN THE
RIGHT ENTRANCE REGION OF THE 250MB JET. A NW-SE CROSS SECTION
THROUGH THE REGION SHOWS STRONG FRONTOGENETICAL BAND WITH IDEAL
FRONTOLYSIS/FRONTOGENETICAL CIRCULATION SETTING UP ACROSS THE AREA
BEGINNING THIS EVENING. STRONG ISENTROPIC UPGLIDE ON THE 305-315K
SURFACES IS PRESENT ALONG WITH DECENT 850 MB MOISTURE TRANSPORT.
DESPITE SOME LOW LEVEL DRY AIR CONCERNS INITIALLY...THAT SHOULD BE
OVERCOME SUCH THAT SHOWERS WILL DEVELOP / MOVE INTO SOUTHEAST
MINNESOTA AND WESTERN WISCONSIN BETWEEN 22-00Z...THEN SAG SOUTHEAST
THROUGH THE NIGHT. THE LATEST MESO MODELS ARE IN GOOD AGREEMENT WITH
THIS SCENARIO AS WELL. REGARDING RAINFALL TOTALS THROUGH THE
EVENT...A NORTH/SOUTH GRADIENT SHOULD SET UP AS BETTER FORCING/LIFT
ACROSS IOWA INTO SOUTHERN WISCONSIN. TOTALS AROUND 1/10 OF AN INCH
ACROSS NORTH CENTRAL WISCONSIN....TO 1/3 TO 1/2 ALONG THE I-90
CORRIDOR...THE UPWARDS OF 3/4 OF AN INCH LOOK PROMISING FOR THE
AREA.
THURSDAY AND FRIDAY...BY 12Z THURSDAY...THE BULK OF THE
PRECIPITATION SHOULD BE ORIENTED THROUGH CENTRAL WISCONSIN TO
NORTHEAST IOWA. TIMING THE PROGRESS OF THIS PRECIPITATION OUT OF THE
FORECAST AREA IS A BIT TRICKY. THIS IS MOST LIKELY DUE TO MODEL
TIMING DIFFERENCES INCREASING ON HOW THE NEXT SHORTWAVE...CURRENTLY
IN NORTHWEST ALBERTA...DIVING SOUTHEAST DURING THE DAY THURSDAY IS
HANDLED. THE 12.00Z NAM IS A SLOWER OUTLIER...WHILE THE 12.00Z
GFS/CANADIAN/ECMWF ARE IN GOOD AGREEMENT. HAVE DISCOUNTED THE NAM
FOR THE TIME BEING...GIVEN TRENDS OVER THE PAST DAY TO BE FASTER.
THE HIGHEST PRECIPITATION CHANCES AFTER 15Z THURSDAY LOOK TO BE
SOUTH/EAST OF A SPARTA WISCONSIN TO OELWEIN IOWA LINE. A COOL DAY ON
TAP FOR THE AREA WITH MOSTLY CLOUDY TO CLOUDY SKIES UNDER COLD AIR
ADVECTION AND 850MB TEMPS PROGGED TO BE 5-8C. AREAS SOUTH/EAST WILL
BE THE COOLEST WITH MORE CLOUDS/RAIN...AND PROBABLY WILL ONLY MAKE
IT TO 60F AT BEST. AS THE NORTHWEST ALBERTA SHORTWAVE DIVES THROUGH
MINNESOTA DURING THE AFTERNOON AND COMBINES WITH DIURNAL
HEATING...SCATTERED SHOWERS ARE POSSIBLE...MAINLY CONFINED TO THE
NORTHWEST AREAS. STEEPER LAPSE RATES AND MAYBE SOME INSTABILITY TO
WORK WITH COULD PRODUCE A RUMBLE OR TWO OF THUNDER AS WELL.
THE NORTHWEST ALBERTA SHORTWAVE QUICKLY PIVOTS THROUGH THE NORTHERN
PLAINS LATE THURSDAY AND BY 06Z FRIDAY SHOULD BE CENTERED ACROSS
WISCONSIN. AT THE SURFACE...BUILDING CANADIAN HIGH PRESSURE THURSDAY
NIGHT INTO FRIDAY MORNING WILL BRING SOME OF THE COLDEST AIR OF THE
AUTUMN SEASON THUS FAR. THE COMBINATION OF PRECIPITABLE WATER VALUES
DROPPING TO A 0.5 INCH OR LESS...DIMINISHING WINDS WITH THE HIGH
PRESSURE AREA BUILDING IN AND CLEARING SKIES WILL ALL HELP
TEMPERATURES TO TANK. LOWS LOOK TO DROP DOWN TO THE LOWER 40S TO
AROUND 40 FOR MOST LOCATIONS. ALONG AND NORTHEAST OF THE I-94
CORRIDOR IN WISCONSIN...THE TYPICAL COLD SPOTS COULD EVEN SEE SOME
PATCHY FROST...THOUGH THIS WOULD ALL HINGE ON THE SURFACE HIGH
POSITION. RIVER VALLEY FOG WOULD ALSO BE A CONCERN GIVEN THIS
SYNOPTIC SETUP...ESPECIALLY GIVEN EXPECTED RAINFALL OVER THE NEXT 36
HOURS AND THE COOLER AND CLOUDIER DAY EXPECTED THURSDAY. RIGHT NOW
THE GFS IS A FASTER OUTLIER IN BRINGING IN THE SURFACE HIGH...MAKING
ITS SOLUTION THE MOST FAVORABLE FOR WIDESPREAD VALLEY FOG AND ALSO
MORNING FROST ACROSS NORTH CENTRAL WISCONSIN. DEFINITELY SOMETHING
TO WATCH CLOSELY IN THE NEXT FORECAST RUNS. FOR NOW HAVE ONLY
INCLUDED AREAS OF FOG FOR THE WISCONSIN RIVER AND ITS TRIBUTARIES...
AND PATCHY FOG FOR THE MISSISSIPPI RIVER. FRIDAY LOOKS TO BE A VERY
PLEASANT DAY FOR THE ENTIRE UPPER MIDWEST WITH THE HIGH PRESSURE
DRIFTING OVERHEAD...PROVIDING LIGHT WINDS. 850MB TEMPS OF 6-8C AND
PLENTY OF SUN SHOULD RESULT IN HIGHS SLIGHTLY BELOW NORMAL...IN THE
UPPER 60S TO LOWER 70S.
QUIET WEATHER LOOKS TO PERSIST INTO FRIDAY NIGHT WITH THE HIGH
PRESSURE REMAINING NEARBY. LOW PRECIPITABLE WATER VALUES ARE STILL
SUGGESTED...SO ANOTHER COOL NIGHT IS EXPECTED WITH LOWS IN THE UPPER
30S AT THE TYPICAL COLD SPOTS AND LOW TO MID 40S ELSEWHERE. MAY
AGAIN BE DEALING WITH VALLEY FOG AND FROST.
.LONG TERM...SATURDAY THROUGH TUESDAY NIGHT
339 AM CDT WED SEP 12 2012
12.00Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE IN MUCH BETTER
AGREEMENT ON THE UPPER LEVEL PATTERN COMPARED TO THE PAST FEW DAYS
FOR THE LONG TERM FORECAST. THERE STILL ARE SOME ISSUES...MOSTLY
IMPACTING TUESDAY AND TUESDAY NIGHT.
TO BEGIN THE LONG TERM FORECAST...NEARLY ZONAL FLOW EXISTS WITH THE
WESTERLIES RUNNING ACROSS SOUTHERN CANADA. WITHIN THIS FLOW...
THOUGH...THERE IS A POTENT SHORTWAVE CROSSING NORTHERN SASKATCHEWAN
WITH INDICATIONS OF TROUGHING BEGINNING TO FORM OVER WESTERN
ALBERTA. THIS TROUGHING ENDS UP DEEPENING ACROSS CENTRAL CANADA BY
LATE SUNDAY DUE TO RIDGING BUILDING UP INTO BRITISH COLUMBIA. AHEAD
OF THIS UPPER TROUGHING AND ASSOCIATED WITH THAT POTENT SHORTWAVE...
MODELS DEPICT A COLD FRONT. THIS FRONT LOOKS TO CROSS THE FORECAST
AREA SUNDAY NIGHT AT THE PRESENT TIME...WHICH IS WHEN THE TROUGHING
BEGINS TO DIG DOWN INTO THE NORTH CENTRAL U.S.. ANTICIPATING DRY
WEATHER UNTIL THIS FRONT PASSES...DUE TO THE DRY AIRMASS AHEAD OF
IT. WITH 850MB TEMPS RUNNING AROUND 8C ON SATURDAY AND 10-12C ON
SUNDAY...HIGH TEMPERATURES BOTH DAYS SHOULD BE ABLE TO TOP OUT IN
THE 70S. CHANGES ARE DEFINITELY ON THE WAY FOR MONDAY...THOUGH...AS
THE UPPER TROUGH APPROACHES THE AREA. LIKE TODAY THROUGH THURSDAY...
INDICATIONS ARE THAT A FRONTOGENETIC BAND OF PRECIPITATION WILL FORM
BEHIND THE COLD FRONT. HOW MUCH PRECIPITATION FORMS DEPENDS ON HOW
MUCH THE UPPER TROUGHING DIGS DOWN INTO THE NORTH CENTRAL U.S....
WHICH IS A LITTLE UNCERTAIN AT THIS TIME. THEREFORE...WILL BE
FOLLOWING THE CONSENSUS PRECIPITATION CHANCES OF 30-40 FOR MONDAY
AND MONDAY NIGHT. IF MODEL TRENDS CONTINUE...CHANCES ARE LIKELY
GOING TO BE RAISED IN LATER FORECASTS FOR MONDAY AND MONDAY NIGHT.
THE FORECAST FOR TUESDAY AND TUESDAY NIGHT ALSO RELY ON WHAT HAPPENS
WITH THE NORTH CENTRAL U.S. TROUGH. THE 12.00Z GFS FORMS A CLOSED
UPPER LOW OVER THE FORECAST AREA WHILE THE 11.12Z/12.00Z ECMWF KEEP
THE TROUGH PROGRESSIVE. THE FORMER SCENARIO YIELDS WET WHILE THE
LATTER SCENARIO SUGGESTS DRY...THOUGH BOTH ARE COOL AS 850MB TEMPS
TUMBLE TO A CHILLY 0-2C. 12.00Z GFS ENSEMBLES SUGGESTS BOTH THE GFS
AND ECMWF ARE POSSIBLE...THEREFORE 20-30 PERCENT CHANCES OF
PRECIPITATION ARE IN THE FORECAST. HIGHS TUESDAY WILL BE AT LEAST 15
DEGREES COLDER THAN THOSE ON SUNDAY...IF NOT MORE.
&&
.AVIATION...THROUGH 06Z THURSDAY
1149 PM CDT TUE SEP 11 2012
A COLD FRONT EXTENDED FROM NORTHWEST WISCONSIN INTO NORTHWEST IOWA
LATE THIS EVENING. THIS FRONT IS EXPECTED TO MOVE THROUGH THE TAF
SITES BETWEEN 12 AND 15Z WEDNESDAY BRINGING THE WINDS AROUND TO
THE NORTHWEST AND THEN NORTH. REGIONAL RADARS SHOWING SOME SHOWERS
ALONG AND BEHIND THE FRONT WITH SOME RAIN HITTING THE GROUND OVER
WESTERN MINNESOTA INTO SOUTH DAKOTA. THIS IS OCCURRING IN A ZONE
OF 1000-850 MB FRONTOGENESIS WHICH WILL MOVE INTO THE AREA BEHIND
THE FRONT. BOTH THE 12.12Z HI-RES ARW AND NMM BROUGHT SOME SHOWERS
INTO THE KRST AREA WEDNESDAY MORNING IN THIS ZONE OF FRONTOGENESIS...
SO HAVE CONTINUED THE INCLUSION OF SOME VCSH. BOTH MODELS SHOW
THESE WEAKENING AS THEY WORK DEEPER INTO THE DRY AIR SO FOR NOW
HAVE NOT INCLUDED AT KLSE. THE FORCING BECOMES STRONGER DURING THE
LATE AFTERNOON AND EVENING AS THE FRONTOGENESIS BECOME MODERATE IN
STRENGTH DEEPENS UP TO 500 MB. SOME LIFT WILL ALSO BE PROVIDED
FROM AN APPROACHING SHORT WAVE TROUGH AND WITH UP TO 6 UBAR/S OF
UP GLIDE ON THE 305K ISENTROPIC SURFACE. HAVE INCLUDED CATEGORICAL
SHOWERS FOR BOTH SITES WITHOUT ANY VISIBILITY RESTRICTIONS AT THIS
POINT. THE FORCING LOOKS TO TRANSITION EAST FAIRLY QUICK THAT THE
SHOWERS SHOULD END BEFORE 06Z THURSDAY IN KRST AND SHORTLY AFTER
AT KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
339 AM CDT WED SEP 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1213 PM MDT WED SEP 12 2012
.UPDATE...
AVIATION...18Z TAF ISSUANCE...LIGHT RAIN LOOKS TO CONTINUE ACROSS
SOUTHERN PORTIONS OF THE NEBRASKA PANHANDLE THROUGH AROUND 20Z.
EXPECTING IFR CONDITIONS TO PERSIST AT KCYS...KSNY AND KBFF AS
WELL THROUGH THIS TIME...BUT WILL EVENTUALLY LIFT THROUGH THE LATE
AFTERNOON. ELSEWHERE...MVFR TO VFR CIGS WILL STEADILY LIFT THROUGH
THE AFTERNOON WITH GENERALLY LIGHT WINDS. A RETURN OF LOW MVFR TO
IFR VSBYS IS EXPECTED OVERNIGHT FROM KLAR EAST TO KCYS...KBFF AND
KSNY AS THE MIDLEVEL CLOUD DECK DEPARTS TO THE SOUTH AND
RADIATIONAL COOLING WITH RESIDUAL MOISTURE DEVELOPS PATCHY AREAS
OF FOG. WESTERLY SFC WINDS WILL DRY THINGS OUT COME MORNING...WITH
VFR CONDITIONS AND LIGHT WINDS EXPECTED FOR THURSDAY. RJM
&&
.PREV DISCUSSION... /ISSUED 1047 AM MDT WED SEP 12 2012/
UPDATE...
LIGHT RAIN ACTIVITY CONTINUES TO DECREASE AND IS MAINLY CONFINED
TO AREAS NEAR THE COLORADO BORDER. DO NOT THINK WE WILL SEE MUCH
CLEARING OF THE LOW CLOUDS OVER EXTREME SOUTHEAST WY AND THE
SOUTHERN NEBRASKA PANHANDLE WITH ABUNDANT LLVL MOISTURE FROM
RECENT RAINS AND LIGHT SE UPSLOPE IN PLACE. THE HRRR MODEL OUTPUT
SHOWS IFR CONDITIONS PERSISTING THROUGH THE ENTIRE AFTERNOON ALONG
AND JUST EAST OF THE SOUTHERN LARAMIE RANGE. HIGHS WILL BE QUITE
COOL TODAY WITH THE PERSISTENT LOW CLOUDS.
PREV DISCUSSION... /ISSUED 342 AM MDT WED SEP 12 2012/
SHORT TERM...TODAY THROUGH FRIDAY...
TODAY...WSR-88D REFLECTIVITY LOOP SHOWS LIGHT RAIN SOUTHEAST OF A
CHEYENNE TO CHADRON LINE. FOR THIS MORNING...THE NAM SHOWS THIS BAND
OF LIGHT RAIN PERSISTING...THUS HAVE CONTINUED WITH 50 TO 90 PERCENT
CHANCE OF RAIN THIS AREA. WITH TEMPERATURE AND DEWPOINT SPREADS
CLOSE...HAVE ALSO KEPT IN THE MENTION OF FOG THIS MORNING. THE CLOUD
SHIELD AND BAND OF RAIN WILL CONTINUE TO BE SQUEEZED TO OUR FAR
SOUTHERN COUNTIES THIS AFTERNOON...LIMITING WARM UP FROM CHEYENNE TO
SIDNEY. ELSEWHERE...CLEARING SKIES WILL PROMOTE WARMER TEMPERATURES.
TONIGHT...SURFACE HIGH PRESSURE MOVING OVERHEAD ALONG WITH CLEARING
SKIES WILL PROMOTE EXCELLENT RADIATION COOLING ALONG WITH AREAS OF
FOG EAST OF A LARAMIE TO LUSK LINE...DESPITE LIGHT WEST WINDS IN THE
LOW LEVELS.
THURSDAY...WARMING TREND ON TAP AS RIDGING ALOFT PREVAILS AND SUNNY
SKIES ABOUND. COOL NORTHEAST UPSLOPE WINDS WILL LIMIT WARMING
SOMEWHAT EAST OF INTERSTATE 25.
THURSDAY NIGHT...RETURN SOUTHERLY WINDS WILL LIMIT COOLING DESPITE
CLEAR SKIES.
FRIDAY...WARMING TREND CONTINUES WITH RETURN SOUTHERLY WINDS AND A
RIDGE ALOFT OVER THE SOUTHWEST AND ROCKY MOUNTAIN STATES.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...
THE 00Z MEDIUM RANGE MODEL SOLUTIONS ARE CONSISTENT DEPICTING A
PROGRESSIVE UPPER LEVEL PATTERN ACROSS THE LOWER 48. A BROAD RIDGE
OVER THE WESTERN HALF OF THE CONUS EARLY IN THE PERIOD WILL YIELD TO
A DIGGING TROUGH FROM CENTRAL CANADA INTO THE NORTH CENTRAL STATES
AS A RIDGE AMPLIFIES ALONG THE WEST COAST LATE THIS WEEKEND INTO
EARLY NEXT WEEK.
SURFACE RIDGES WILL BE SITUATED WEST OF THE CONTINENTAL DIVIDE AND
EASTERN GREAT PLAINS...WITH A SURFACE TROUGH ALIGNED NORTH-SOUTH
OVER THE HIGH PLAINS THIS WEEKEND. DRY CONDITIONS WILL PREVAIL
FRIDAY NIGHT THROUGH SATURDAY NIGHT. SUNDAY MORNING...A CANADIAN
COLD FRONT WILL PROGRESS SMARTLY SOUTHWARD THROUGH MONTANA AND
THE DAKOTAS AND THROUGH WYOMING SUNDAY AFTERNOON. AHEAD OF THE
FRONT...A FEW SHOWERS OR TSTORMS MAY DEVELOP WEST OF THE LARAMIE
RANGE SUNDAY AFTERNOON. IT WILL BE BREEZY WITH WESTERLY WINDS
SHIFTING TO NORTHERLY IN THE WAKE OF THE FRONTAL PASSAGE. THE
SHOWER COVERAGE INCREASES IN THE POST-FRONTAL UPSLOPE FLOW PATTERN
SUNDAY NIGHT AND MONDAY MORNING. HOWEVER...QPF AMOUNTS WILL BE LIGHT.
THE SHOWERS WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST MONDAY
AFTERNOON WITH A COOL SURFACE RIDGE BUILDING SOUTH ALONG THE
EASTERN WYOMING PLAINS AND NEBRASKA PANHANDLE. THE CENTER OF THE
RIDGE WILL BE CENTERED OVER THE CENTRAL GREAT PLAINS ON TUESDAY.
DOWNSLOPING WESTERLY FLOW AND 700MB TEMPERATURES 9 TO 12 DEG C
WILL EQUATE TO HIGHS IN THE 80S FOR THE PLAINS ON SATURDAY. HIGH
TEMPERATURES SUNDAY WILL OCCUR EARLY AFTERNOON OVER NORTHERN ZONES
AND LATER FOR SOUTHERN ZONES BASED ON THE TIMING OF THE FRONTAL
PASSAGE. IT WILL BE MUCH COOLER MONDAY WITH 700MB TEMPERATURES
FALLING TO -2 TO -6 DEG C WHICH WILL KEEP HIGH TEMPERATURES IN
THE 50S AND 60S. 700MB TEMPERATURES REBOUND TO 3 TO 7 DEG C
TUESDAY AFTERNOON. EXPECT NEAR AVERAGE HIGHS IN THE 70S LOWER
ELEVATIONS AND 50S AND 60S HIGHER ELEVATIONS.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS TODAY DUE TO RELATIVELY HIGH HUMIDITIES.
MINIMUM HUMIDITIES WILL CONTINUE TO DECREASE THE NEXT SEVERAL DAYS
WITH NEAR CRITICAL HUMIDITIES OVER THE WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...FINCH
SHORT TERM/FIRE WEATHER...RUBIN
LONG TERM...JAMSKI
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1047 AM MDT WED SEP 12 2012
.UPDATE...
LIGHT RAIN ACTIVITY CONTINUES TO DECREASE AND IS MAINLY CONFINED
TO AREAS NEAR THE COLORADO BORDER. DO NOT THINK WE WILL SEE MUCH
CLEARING OF THE LOW CLOUDS OVER EXTREME SOUTHEAST WY AND THE
SOUTHERN NEBRASKA PANHANDLE WITH ABUNDANT LLVL MOISTURE FROM
RECENT RAINS AND LIGHT SE UPSLOPE IN PLACE. THE HRRR MODEL OUTPUT
SHOWS IFR CONDITIONS PERSISTING THROUGH THE ENTIRE AFTERNOON ALONG
AND JUST EAST OF THE SOUTHERN LARAMIE RANGE. HIGHS WILL BE QUITE
COOL TODAY WITH THE PERSISTENT LOW CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 342 AM MDT WED SEP 12 2012/
SHORT TERM...TODAY THROUGH FRIDAY...
TODAY...WSR-88D REFLECTIVITY LOOP SHOWS LIGHT RAIN SOUTHEAST OF A
CHEYENNE TO CHADRON LINE. FOR THIS MORNING...THE NAM SHOWS THIS BAND
OF LIGHT RAIN PERSISTING...THUS HAVE CONTINUED WITH 50 TO 90 PERCENT
CHANCE OF RAIN THIS AREA. WITH TEMPERATURE AND DEWPOINT SPREADS
CLOSE...HAVE ALSO KEPT IN THE MENTION OF FOG THIS MORNING. THE CLOUD
SHIELD AND BAND OF RAIN WILL CONTINUE TO BE SQUEEZED TO OUR FAR
SOUTHERN COUNTIES THIS AFTERNOON...LIMITING WARM UP FROM CHEYENNE TO
SIDNEY. ELSEWHERE...CLEARING SKIES WILL PROMOTE WARMER TEMPERATURES.
TONIGHT...SURFACE HIGH PRESSURE MOVING OVERHEAD ALONG WITH CLEARING
SKIES WILL PROMOTE EXCELLENT RADIATION COOLING ALONG WITH AREAS OF
FOG EAST OF A LARAMIE TO LUSK LINE...DESPITE LIGHT WEST WINDS IN THE
LOW LEVELS.
THURSDAY...WARMING TREND ON TAP AS RIDGING ALOFT PREVAILS AND SUNNY
SKIES ABOUND. COOL NORTHEAST UPSLOPE WINDS WILL LIMIT WARMING
SOMEWHAT EAST OF INTERSTATE 25.
THURSDAY NIGHT...RETURN SOUTHERLY WINDS WILL LIMIT COOLING DESPITE
CLEAR SKIES.
FRIDAY...WARMING TREND CONTINUES WITH RETURN SOUTHERLY WINDS AND A
RIDGE ALOFT OVER THE SOUTHWEST AND ROCKY MOUNTAIN STATES.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...
THE 00Z MEDIUM RANGE MODEL SOLUTIONS ARE CONSISTENT DEPICTING A
PROGRESSIVE UPPER LEVEL PATTERN ACROSS THE LOWER 48. A BROAD RIDGE
OVER THE WESTERN HALF OF THE CONUS EARLY IN THE PERIOD WILL YIELD TO
A DIGGING TROUGH FROM CENTRAL CANADA INTO THE NORTH CENTRAL STATES
AS A RIDGE AMPLIFIES ALONG THE WEST COAST LATE THIS WEEKEND INTO
EARLY NEXT WEEK.
SURFACE RIDGES WILL BE SITUATED WEST OF THE CONTINENTAL DIVIDE AND
EASTERN GREAT PLAINS...WITH A SURFACE TROUGH ALIGNED NORTH-SOUTH
OVER THE HIGH PLAINS THIS WEEKEND. DRY CONDITIONS WILL PREVAIL
FRIDAY NIGHT THROUGH SATURDAY NIGHT. SUNDAY MORNING...A CANADIAN
COLD FRONT WILL PROGRESS SMARTLY SOUTHWARD THROUGH MONTANA AND
THE DAKOTAS AND THROUGH WYOMING SUNDAY AFTERNOON. AHEAD OF THE
FRONT...A FEW SHOWERS OR TSTORMS MAY DEVELOP WEST OF THE LARAMIE
RANGE SUNDAY AFTERNOON. IT WILL BE BREEZY WITH WESTERLY WINDS
SHIFTING TO NORTHERLY IN THE WAKE OF THE FRONTAL PASSAGE. THE
SHOWER COVERAGE INCREASES IN THE POST-FRONTAL UPSLOPE FLOW PATTERN
SUNDAY NIGHT AND MONDAY MORNING. HOWEVER...QPF AMOUNTS WILL BE LIGHT.
THE SHOWERS WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST MONDAY
AFTERNOON WITH A COOL SURFACE RIDGE BUILDING SOUTH ALONG THE
EASTERN WYOMING PLAINS AND NEBRASKA PANHANDLE. THE CENTER OF THE
RIDGE WILL BE CENTERED OVER THE CENTRAL GREAT PLAINS ON TUESDAY.
DOWNSLOPING WESTERLY FLOW AND 700MB TEMPERATURES 9 TO 12 DEG C
WILL EQUATE TO HIGHS IN THE 80S FOR THE PLAINS ON SATURDAY. HIGH
TEMPERATURES SUNDAY WILL OCCUR EARLY AFTERNOON OVER NORTHERN ZONES
AND LATER FOR SOUTHERN ZONES BASED ON THE TIMING OF THE FRONTAL
PASSAGE. IT WILL BE MUCH COOLER MONDAY WITH 700MB TEMPERATURES
FALLING TO -2 TO -6 DEG C WHICH WILL KEEP HIGH TEMPERATURES IN
THE 50S AND 60S. 700MB TEMPERATURES REBOUND TO 3 TO 7 DEG C
TUESDAY AFTERNOON. EXPECT NEAR AVERAGE HIGHS IN THE 70S LOWER
ELEVATIONS AND 50S AND 60S HIGHER ELEVATIONS.
AVIATION...12Z TAF ISSUANCE...
POST-FRONTAL NORTHEASTERLY UPSLOPE WINDS AND AMPLE MOISTURE WILL
PROMOTE MVFR TO IFR CEILINGS AND VISIBILITIES ALONG AND EAST OF A
LARAMIE TO SCOTTSBLUFF LINE THIS MORNING. SOME MVFR CEILINGS MAY
LINGER THROUGH MID AFTERNOON AT CHEYENNE...SIDNEY AND SCOTTSBLUFF
BEFORE IMPROVING TO VFR. SKIES WILL CLEAR THIS EVENING WITH LIGHT
SOUTHEASTERLY WINDS.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS TODAY DUE TO RELATIVELY HIGH HUMIDITIES.
MINIMUM HUMIDITIES WILL CONTINUE TO DECREASE THE NEXT SEVERAL DAYS
WITH NEAR CRITICAL HUMIDITIES OVER THE WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...FINCH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
415 AM EDT FRI SEP 14 2012
.DISCUSSION...
...BOATING CONDITIONS LESS THAN IDEAL BUT NO ADVISORIES IN EFFECT...
...PRECIPITATION CHANCES INCREASING FOR EARLY NEXT WEEK...
TODAY/TONIGHT...ONSHORE FLOW WILL CONTINUE TODAY BUT SFC HIGH
PRESSURE RIDGE WILL BEGIN TO WEAKEN AS FRONTAL BOUNDARY APPROACHES
THE EASTERN SEABOARD. LIKEWISE IN THE MID LEVELS...HIGH PRESSURE
RIDGE IS WEAKENING WHICH MAY PRODUCE A BETTER CHANCE FOR THUNDER.
IN ADDITION...THE RESULTING WEAKER STEERING FLOW WILL PRODUCE
SLOWER MOVING SHOWERS/ISOLATED STORMS AND CONTRIBUTE TO LOCALLY
HEAVIER RAINFALL. MAX TEMPS UPPER 80S COAST/LOWER 90S INTERIOR.
HAVE BEEN TRACKING A SMALL LOW LEVEL PERTURBATION IN THE ONSHORE
FLOW SHOWN BY THE RUC MODEL WHICH IS GENERATING CLUSTERS OF
SHOWERS OFFSHORE. EXPECT THESE SHOWERS TO REACH THE COAST (BREVARD
SOUTHWARD) LATER THIS MORNING. SHOWERS SHOULD PUSH WELL INLAND
WITH SOME DEVELOPMENT OF ADDITIONAL SHOWERS INLAND FROM THE COAST
AS DAYTIME INSTABILITY INCREASES. AND AS MENTIONED ABOVE...A FEW
OF THESE SHOWERS HAVE A SLIGHTLY BETTER CHANCE OF DEVELOPING INTO
LIGHTNING STORMS THAN PREVIOUS DAYS. SO HAVE DRAWN 30-40 POPS.
SUFFICIENT LOW LEVEL MOISTURE AND ONSHORE FLOW SHOULD REMAIN IN
PLACE TONIGHT TO SUPPORT CHANCE FOR SHOWERS ALONG THE COAST SOUTH
OF THE CAPE...SLIGHT CHANCE ELSEWHERE.
SAT-SUN...SURFACE HIGH PRESSURE WILL AGAIN ESTABLISH ITSELF ACROSS
THE EASTERN SEABOARD. THIS WILL ACT TO REINFORCE NORTHEAST OR
EAST-NORTHEAST LOW-LEVEL FLOW ACROSS EAST CENTRAL FLORIDA.
HOWEVER...A DRIER AND MORE STABLE AIR MASS WILL SCOUR OUT DEEP LAYER
MOISTURE ACROSS THE EASTERN PENINSULA. FOR NOW WILL KEEP INHERITED
30 PERCENT POPS OVER THE AREA WITH SCATTERED SHOWERS AND ISOLATED
AFTERNOON STORMS. THE FOCUS OF PRECIPITATION WILL SHIFT INTO THE
INTERIOR DURING THE AFTERNOON WITH THE EAST COAST SEA BREEZE. WILL
GO WITH A SLIGHT CHANCE...20 PERCENT POP ALONG THE COAST FOR SUN
WITH 30 PERCENT CHANCES INLAND...AGAIN WITH GREATEST CHANCES ACROSS
THE INTERIOR INTO THE AFTERNOON. MAINLY A NORTHERLY COMPONENT FOR
STEERING FLOW AROUND 5 MPH EACH DAY.
MON-THU...SURFACE HIGH PRESSURE JUST OFF OF THE MID ATLANTIC COAST
EARLY IN THE PERIOD WILL GRADUALLY SHIFT EASTWARD INTO THE WESTERN
ATLANTIC AHEAD OF AN APPROACHING FRONTAL BOUNDARY. HIGH PRESSURE
WILL AGAIN BUILD INTO THE EASTERN SEABOARD ON THU. THE
AFOREMENTIONED FRONT WILL MOVE INTO NORTH FLORIDA MON OVERNIGHT AND
WILL APPEAR TO GET HUNG UP...QUASI-STATIONARY...OVER NORTH-CENTRAL
FLORIDA THROUGH THE REMAINDER OF THE EXTENDED. MOISTURE VALUES WILL
SURGE TOWARD THIS FEATURE LATE ON MON POOLING ACROSS EAST CENTRAL
FLORIDA EACH DAY. PRECIPITATION CHANCES WILL BE ON THE RISE WITH
OCCASIONAL MID-LEVEL IMPULSES MOVING THROUGH THE REGION IN THE
SOUTHWEST FLOW ALOFT. EXPECT 40 TO 50 PERCENT PRECIPITATION CHANCES
EACH DAY. THE PREVIOUS ONSHORE FLOW REGIME WILL RESPOND MON TO THE
APPROACHING FRONTAL BOUNDARY ACROSS THE DEEP SOUTH. WINDS WILL VEER
TO SOUTHEAST ON MON...SOUTHERLY MON NIGHT AND SOUTHWEST ON TUE AS
THE BOUNDARY ENTERS INTO NORTH-CENTRAL FLORIDA. AN UPPER TROUGH
TRAVERSING THE DEEP SOUTH WILL WEAKEN BUT WILL STILL MOVE INTO THE
AREA ON TUE. THIS UPPER TROUGHING WILL ACT TO PUSH DEEP LAYER
RIDGING FURTHER INTO THE WESTERN ATLANTIC. AN UPPER JET SITUATED
ALONG THE EASTERN SEABOARD EXTENDING INTO THE NORTH GOMEX WILL
PROVIDE UPPER DIFFLUENCE ACROSS THE REGION DURING THIS TIME.
STEERING FLOW FOR STORMS MON-THU WILL BE OUT OF THE SOUTHWEST
WHICH FAVORS CONVECTION PILING UP ACROSS THE EASTERN PENINSULA
LATE EACH DAY AND EVENING. AFTERNOON HIGHS WILL CONTINUE NEAR
SEASONAL NORMS WITH OVERNIGHT LOWS SLIGHTLY ABOVE CLIMO.
&&
.AVIATION...
NOT MUCH CHANGE IN THE PATTERN WITH ONSHORE MOVING SHOWERS AND
WILL CONTINUE TO HANDLE WITH VCSH AT TERMINALS. THERE IS A SLIGHT
CHANCE FOR THUNDER. LOW LEVEL WINDS WILL BE 10-15 KNOTS BUT EXPECT
SOME GUSTS TO 20 KNOTS ESP IN AND NEAR SHOWERS.
&&
.MARINE...
TODAY...HIGH PRESSURE RIDGE NORTH OF THE AREA WILL MAINTAIN AN
ONSHORE FLOW BUT WEAKEN SLIGHTLY. WIND SPEEDS 10-15 KNOTS BUT
PRESSURE GRADIENT LOOKS A LITTLE TIGHTER ACROSS VOLUSIA AND
BREVARD COUNTY WATERS WHICH SHOULD PRODUCE A SOLID 15 KNOTS AT
LEAST THIS MORNING. HIGHER GUSTS UP TO 25 KNOTS POSSIBLE IN
SHOWERS. THERE IS A SLIGHTLY BETTER CHANCE FOR A FEW SHOWERS TO
DEVELOP INTO LIGHTNING STORMS. CHOPPY SEAS 4 TO 5 FEET WITH UP TO
6 FEET POSSIBLE OFFSHORE VOLUSIA AND BREVARD. OFTEN CONDITIONS ON
THE OPEN ATLC ARE WORSE THAN WE EXPECT...SO WILL HEADLINE SMALL
CRAFT CAUTION THERE BUT SMALL CRAFT ADVISORIES DO NOT LOOK
WARRANTED.
SAT...SURFACE HIGH PRESSURE WILL SETTLE INTO THE EASTERN SEABOARD ON
THIS DAY. NORTHEAST WINDS OF 10-15 KTS WILL BE COMMON ACROSS THE
COASTAL WATERS. A FEW SHOWERS AND PERHAPS A STORM WILL BE POSSIBLE
WITH DIRECTION OUT OF EITHER THE NORTH OR NORTHEAST.
THE LATEST WAVE WATCH MODEL CONTINUES TO INDICATE SOME LONG PERIOD
SWELLS BOOSTING SEA HEIGHTS TO 5-6 FT SAT OVERNIGHT. THESE SWELLS
ARE FROM TROPICAL CYCLONE NADINE...AND IF THEY MATERIALIZE...WOULD
PRODUCE DANGEROUS INLET CONDITIONS DURING EBB TIDES.
SUN-TUE...A HIGH PRESSURE SYSTEM OVER THE EASTERN SEABOARD WILL
GRADUALLY GET NUDGED EASTWARD INTO THE WESTERN ATLANTIC THROUGH THIS
TIME. ONSHORE FLOW CONTINUES THROUGH SUN...BUT WILL BEGIN TO VEER TO
SOUTHEAST LATE SUN OVERNIGHT INTO MON...AND SOUTHERLY MON
OVERNIGHT...BECOMING SOUTHWEST ON TUE. THIS WILL BE THE RESULT OF
AN APPROACHING FRONTAL BOUNDARY TO THE NORTH. WIND SPEEDS MAINLY
10-15 KTS. ONLY A SMALL THREAT FOR SHOWERS OR LIGHTNING STORMS
WILL BE FORECAST ON SUN. MOISTURE WILL BEGIN TO POOL ACROSS THE
AREA LATE ON MON AHEAD OF THE BOUNDARY WITH OFFSHORE MOVING STORMS
POSSIBLE LATE IN THE DAY/EVENING ON MON. GREATER CHANCES FOR
STORMS MOVING OFFSHORE WILL OCCUR ON TUE AS THE WEAK FRONTAL
BOUNDARY SETTLES INTO NORTH FLORIDA.
LONG PERIOD SWELLS WITH SEA HEIGHTS TO 5-6 FT ARE FORECAST TO
CONTINUE SUN-SUN EVENING. PERSISTENT LONG PERIOD SWELLS CONTINUE
INTO MON-TUE BUT SEA HEIGHTS WILL SUBSIDE TO 3 TO 5 FT DURING THIS
TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 87 75 88 74 / 30 20 20 20
MCO 90 73 91 72 / 40 20 30 20
MLB 88 77 88 76 / 40 30 30 20
VRB 88 75 88 74 / 40 30 30 20
LEE 90 73 91 73 / 30 20 30 20
SFB 89 73 91 73 / 30 20 30 20
ORL 90 74 91 74 / 30 20 30 20
FPR 87 75 88 74 / 40 30 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...KELLY
LONG TERM....SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
200 AM EDT FRI SEP 14 2012
.SHORT TERM (TODAY-SUNDAY)...
THE LATEST NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT OVER THE
WEEKEND AND GENERALLY INDICATES LIGHT TO MODERATE EASTERLY FLOW
CONTINUING JUST NORTH OF A WEAK TROUGH OR WHAT IS LEFT OF THE
FRONTAL BOUNDARY THAT MOVED THROUGH A FEW DAYS AGO AND HIGH PRESSURE
TO THE NORTH. ALTHOUGH THE RAINFALL COVERAGE TODAY IS EXPECTED TO BE
LESS THAN YESTERDAY...SCATTERED SHOWERS OVER THE ADJACENT ATLANTIC
WATERS SPREADING ASHORE ACROSS PORTIONS OF THE EAST COAST AREAS
EARLY THIS MORNING WILL REMAIN POSSIBLE ONCE AGAIN. THIS LINES UP
WELL WITH THE LATEST HRRR AND WRF MODEL REFLECTIVITIES TODAY. FOR
THE AFTERNOON...EXPECT THIS ACTIVITY TO SPREAD INLAND AND BECOME
CONCENTRATED OVER THE INTERIOR AND WESTERN AREAS THROUGH THE EVENING
HOURS BEFORE DIMINISHING. THE EASTERLY FLOW HAS WEAKENED COMPARED TO
YESTERDAY...WHICH SHOULD ALLOW A WEST COAST SEA BREEZE TO BECOME
ESTABLISHED THIS AFTERNOON. THE MAIN IMPACTS FROM THIS
AFTERNOON/EVENING ACTIVITY WILL BE THE POTENTIAL FOR PERIODS WITH
HEAVY RAIN AND GUSTY WINDS WITH ANY STRONGER STORMS THAT DEVELOP.
HOWEVER...MODEL SOUNDINGS ARE NOT THAT IMPRESSIVE AND INDICATE
MEAGER MID-LEVEL LAPSE RATES WITH NEAR AVERAGE 500 MB TEMPERATURES.
OVER THE WEEKEND...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH
TEMPERATURES REMAINING NEAR OR AROUND NORMAL.
.LONG TERM (SUNDAY NIGHT-THURSDAY)...
MODELS CONTINUE TO INDICATE UPPER HEIGHTS FALLING AHEAD OF A
SHORTWAVE TROUGH PROGGED TO TRANSLATE EAST THEN NORTHEAST ACROSS THE
REGION WELL NORTHWEST OF OUR LOCAL AREA SUNDAY THROUGH TUESDAY. THIS
SHORTWAVE COMBINED WITH ANOTHER POTENT PIECE OF ENERGY DIVING
SOUTHEAST OVER THE PLAIN STATES WILL QUICKLY AMPLIFY THE OVERALL
UPPER PATTERN ACROSS THE COUNTRY CHARACTERIZED WITH A DEEPENING
TROUGH OVER THE EASTERN STATES AND RIDGING OUT WEST. THE ATTENDANT
COLD FRONT ASSOCIATED WITH THE LEAD SHORTWAVE IS FORECAST TO SWEEP
EAST ACROSS THE REGION AND GENERALLY LAYOUT FROM EAST TO WEST AND
STALL JUST NORTH OF OUR LOCAL AREA SOMETIME AROUND THE MID-WEEK TIME
FRAME AS IT LOSES ITS UPPER SUPPORT. THE ECMWF AND GFS/GFS ENSEMBLE
MEAN SOLUTIONS APPEAR TO BE IN BETTER AGREEMENT WITH THIS BOUNDARY
SPATIALLY AND TEMPORALLY THROUGH THIS...WHEREAS...24 HRS AGO
INDICATED LARGER DIFFERENCES. IF THIS VERIFIES...EXPECT THE
LOW-LEVEL FLOW LOCALLY TO GRADUALLY VEER TO THE SOUTH AND SOUTHWEST
MONDAY THROUGH TUESDAY AS A WARM FRONT LIFTS NORTH OVER THE EASTERN
GULF AND FL. THE RESULTANT DEEP AND MOIST SOUTHWEST FLOW SHOULD
TRANSLATE TO HIGHER THAN NORMAL RAIN CHANCES...ESPECIALLY OVER THE
NORTH AND NORTHEASTERN SECTIONS OF THE FORECAST AREA FROM THE LAKE
TO PALM BEACH REGION. DUE TO THE BETTER AGREEMENT BETWEEN THE LATEST
MODEL GUIDANCE AND PERSISTENCE FROM RUN TO RUN...WILL SLIGHTLY
INCREASE THE RAINFALL PROBABILITIES MONDAY THROUGH THE MID-WEEK
PERIOD.
&&
.MARINE...
LIGHT TO MODERATE EASTERLY WINDS AND WILL PERSIST THROUGH THE
WEEKEND WITH SCATTERED SHOWERS AND STORMS POSSIBLE...ESPECIALLY
OVERNIGHT AND THROUGH THE EARLY MORNING HOURS ACROSS THE ATLANTIC
WATERS. SEAS WILL GRADUALLY TREND DOWN THROUGH THE WEEKEND TO
AROUND NORMAL. WINDS ARE FORECAST TO SHIFT SOUTH AND POSSIBLY
SOUTHWEST SOMETIME NEXT WEEK FROM MONDAY THROUGH WEDNESDAY AS
ANOTHER FRONTAL BOUNDARY APPROACHES AND STALLS NORTH OF THE MARINE
AREA.
&&
.FIRE WEATHER...
MOIST CONDITIONS WILL KEEP RH`S WELL ABOVE CRITICAL LEVELS THROUGH
THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 77 86 76 / 30 20 30 20
FORT LAUDERDALE 86 78 88 78 / 20 20 30 20
MIAMI 87 78 88 78 / 30 20 40 20
NAPLES 89 74 91 75 / 30 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION
NWS LINCOLN IL
217 AM CDT FRI SEP 14 2012
.DISCUSSION...
ISSUED 217 AM CDT FRI SEP 14 2012
SHORT TERM...TODAY THROUGH SUNDAY
BAND OF POST-FRONTAL PRECIPITATION CONTINUES TO SHIFT SLOWLY
EASTWARD ACROSS CENTRAL ILLINOIS EARLY THIS MORNING. BASED ON
SATELLITE/RADAR LOOPS...IT APPEARS SCATTERED LIGHT SHOWERS WILL BE
CONFINED TO LOCATIONS ALONG AND SOUTH OF A DANVILLE TO TAYLORVILLE
LINE BY 12Z/7AM. THIS PRECIP WILL GRADUALLY SETTLE SOUTH OF THE
KILX CWA BY MID TO LATE MORNING...FOLLOWED BY CLEARING SKIES
ACROSS THE BOARD BY AFTERNOON. WITH CLEARING OF LOW CLOUDINESS
ALREADY TAKING PLACE NORTHWEST OF THE ILLINOIS RIVER...THE PROBLEM
ACROSS THE FAR NORTHWEST CWA WILL LIKELY BE FOG THIS MORNING.
07Z/2AM OB FROM KGBG SHOWS 1/4SM VISBY...WITH WIDESPREAD 1/2 TO
1/4SM VISBYS ACROSS EASTERN IOWA AND NORTHWESTERN ILLINOIS. WILL
MONITOR THIS AREA CLOSELY FOR A POTENTIAL DENSE FOG ADVISORY. AT
THIS POINT...WILL INCLUDE AREAS OF FOG DURING THE EARLY MORNING
ALONG AND WEST OF I-55...WITH AREAS OF DENSE FOG FURTHER NORTHWEST
ACROSS KNOX AND STARK COUNTIES. ONCE THE FOG DISSIPATES AND THE
SHOWERS ACROSS THE SE COME TO AN END...SUNNY SKIES AND DRY WEATHER
WILL BE THE RULE ACROSS THE ENTIRE AREA THIS AFTERNOON.
WITH HIGH PRESSURE BUILDING INTO THE REGION TONIGHT...CLEAR SKIES
AND LIGHT WINDS WILL ALLOW EXCELLENT RADIATIONAL COOLING
CONDITIONS TO DEVELOP. SINCE THERE WILL BE QUITE A BIT OF SUNSHINE
AND MIXING THIS AFTERNOON...AND A VERY DRY AIRMASS IS ADVECTING IN
FROM THE NORTHWEST...DO NOT THINK FOG WILL DEVELOP TONIGHT.
INSTEAD...IT WILL BE A CLEAR AND VERY COOL NIGHT...WITH LOWS
DIPPING INTO THE 40S.
WITH SURFACE HIGH PRESSURE HOLDING FIRM THROUGHOUT THE
WEEKEND...EXPECT DRY WEATHER BOTH SATURDAY AND SUNDAY. UPPER WAVE
CURRENTLY NOTED ON WATER VAPOR IMAGERY OVER THE TEXAS PANHANDLE IS
PROGGED TO SHIFT EASTWARD INTO THE TENNESSEE RIVER VALLEY SUNDAY
NIGHT INTO MONDAY...HOWEVER IT APPEARS ANY PRECIP ASSOCIATED WITH
THIS FEATURE WILL REMAIN SOUTH OF ILLINOIS.
LONG TERM...MONDAY THROUGH THURSDAY
THE MAIN STORY IN THE EXTENDED WILL BE THE COOL WEATHER NEXT
WEEK...AS UPPER RIDGE BUILDS WEST OF THE ROCKIES AND DEEP TROUGH
SETTLES IN ACROSS THE MIDWEST/GREAT LAKES. VIGOROUS SHORT-WAVE
TROUGH WILL APPROACH FROM THE NORTHWEST ON MONDAY...PUSHING A
COLD FRONT INTO CENTRAL ILLINOIS. BOTH THE GFS AND ECMWF ARE IN
GOOD AGREEMENT CONCERNING THE TIMING OF THE FRONT...WITH BOTH
MODELS SUGGESTING SCATTERED SHOWERS/STORMS MONDAY AFTERNOON AND
EVENING. GFS BRINGS 60 TO 65F SURFACE DEWPOINTS NORTHWARD INTO THE
AREA AHEAD OF THE ADVANCING FRONT MONDAY AFTERNOON. THIS RESULTS
IN MODEST CAPE VALUES OF 500 TO 1000J/KG. STRONGEST 0-6KM SHEAR
APPEARS TO LAG BEHIND THE FRONT...SO INSTABILITY/SHEAR PARAMETERS
NEVER COINCIDE WITH ONE ANOTHER. AS A RESULT...AM EXPECTING MAINLY
SHOWERS...WITH A FEW EMBEDDED THUNDERSTORMS AS THE FRONT PASSES.
MODEL CONSENSUS TAKES BOUNDARY EAST OF ILLINOIS BY LATE MONDAY
NIGHT...SO COOL/DRY WEATHER WILL RETURN ON TUESDAY. AIRMASS BEHIND
FRONT WILL BE MUCH COOLER...WITH THE GFS SHOWING THE 0C 850MB
ISOTHERM DIPPING INTO NORTH-CENTRAL ILLINOIS. THINK THIS MAY BE A
BIT TOO COOL...BUT EVEN THE SLIGHTLY WARMER ECMWF SUGGESTS HIGH
TEMPS WILL ONLY MAKE IT INTO THE MIDDLE TO UPPER 60S. AFTER A
QUICK WARM-UP ON WEDNESDAY...ANOTHER SHORT-WAVE TROUGH AND
ASSOCIATED COLD FRONT WILL APPROACH WEDNESDAY NIGHT. WILL CARRY A
CHANCE FOR SHOWERS AS THE FRONT MOVES THROUGH...FOLLOWED BY
ANOTHER SHOT OF COOL/DRY AIR FOR THE END OF NEXT WEEK.
BARNES
&&
.AVIATION...
ISSUED 1145 PM CDT THU SEP 13 2012
A WEAKENING BAND OF LIGHT RAIN SHOWERS OVER CENTRAL IL FROM THE IL
RIVER SE TO I-72 BEHIND A COLD FRONT (PRESSING INTO FAR SE IL LATE
THIS EVENING) WILL GRADUALLY DIMINISH FROM NW TO SE DURING THE
OVERNIGHT HOURS. LIGHT RAIN SHOWERS COULD BRING VSBYS DOWN TO 5-7
MILES AND CEILINGS AS LOW AS 1-2K FT OR BRIEFLY JUST BELOW 1K FT
NEXT FEW HOURS. HI-RESOLUTION MODELS LIKE HRRR AND RUC13 HAVE
SLOWED THE CLEARING OF THE CLOUDS OVERNIGHT AND IF THIS VERIFIES
THEN FOG FORMATION IS LESS LIKELY LATER TONIGHT OVER CENTRAL IL.
SCATTERED OUT MID LEVEL CLOUDS BETWEEN 10Z-15Z AND BRING MVFR VSBYS
OF 3-5 MILES WITH FOG AT PIA WHICH IS SOONER TO SCATTER OUT. CLOUD
COVER CURRENLY FAIRLY EXPANSIVE UPSTREAM OVER CENTRAL/SOUTHERN IA
AND NORTHERN MO...SO DELAY IN CLEARING SEEMS REASONABLE. 1031 MB
HIGH PRESSURE OVER NW KS AND RIDGING INTO SE IA/NW IL WILL WEAKEN
TO 1026 MB AS IT SETTLES INTO CENTRAL IL DURING FRIDAY AFTERNOON
AND BRING FAIR WEATHER WITH JUST FEW- SCATTERED CUMULUS CLOUDS
MAINLY AT DEC AND CMI AND SCATTERED CIRRUS. CLEAR SKIES EXPECTED
BY FRIDAY EVENING. NNE WINDS OF 5-10 KTS OVERNIGHT WILL BECOME
LIGHT AND VARIABLY BY SUNSET FRIDAY.
KH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1147 PM CDT THU SEP 13 2012
.DISCUSSION...
ISSUED 855 PM CDT THU SEP 13 2012
UPDATED THE FORECAST TONIGHT FOR SLOWER TRENDS WITH SHOWERS MOVING
SOUTHEAST INTO CENTRAL/SOUTHEAST IL ALONG WITH SLOWER CLEARING OF
THE CLOUDS FROM NW TO SE OVERNIGHT AND FRI MORNING. BUMPED UP LOWS
A FEW DEGREES INTO THE UPPER 50S AND LOWER 60S OVER SOUTHEAST IL.
COLD FRONT WAS OVER CENTRAL INDIANA INTO SOUTHEAST IL NEAR I-70 AND
INTO SE MO TO WEAK 1018 MB LOW PRESSURE IN WEST CENTRAL AR. BAND
OF SHOWERS BEHIND THE COLD FRONT ABOUT 100 MILES WIDE WAS OVER THE
IL RIVER VALLEY AND HAS BEEN ONLY VERY SLOWLY MOVING TO THE SOUTHEAST.
THE RAIN SO FAR THIS EVENING HAS BEEN MAINLY ALONG AND NW OF THE
IL RIVER. TEMPERATURES RANGE FROM THE MID 50S NW OF THE IL RIVER
TO THE LOWER 70S AHEAD OF THE COLD FRONT SE OF I-70. SO A TASTE OF
FALL WEATHER LIES BEHIND THE COLD FRONT ACROSS CENTRAL IL RIGHT NOW.
USED THE HRRR AND RUC13 MODELS TO TIME THE BAND OF RAIN SHOWERS
PRESSING SE THROUGH CENTRAL IL TONIGHT...NOT REACHING SE IL UNTIL
LATE TONIGHT INTO FRI MORNING. HAVE CLOUDS DECREASING ACROSS THE
IL RIVER VALLEY AFTER 2 AM. CLOUDS CURRENTLY EXTEND UPSTREAM
ACROSS CENTRAL/SE IOWA. NORTH WINDS OF 5 TO 15 MPH AND A FEW GUSTS
NEAR 20 MPH EARLY TO DIMINISH UNDER 10 MPH DURING OVERNIGHT. THIS
DUE TO 1029 MB HIGH PRESSURE OVER NORTHERN KS INTO SOUTHERN IA
THAT NOSES INTO THE IL RIVER VALLEY FRI MORNING.
KH
&&
.AVIATION...
ISSUED 1145 PM CDT THU SEP 13 2012
A WEAKENING BAND OF LIGHT RAIN SHOWERS OVER CENTRAL IL FROM THE IL
RIVER SE TO I-72 BEHIND A COLD FRONT (PRESSING INTO FAR SE IL LATE
THIS EVENING) WILL GRADUALLY DIMINISH FROM NW TO SE DURING THE
OVERNIGHT HOURS. LIGHT RAIN SHOWERS COULD BRING VSBYS DOWN TO 5-7
MILES AND CEILINGS AS LOW AS 1-2K FT OR BRIEFLY JUST BELOW 1K FT
NEXT FEW HOURS. HI-RESOLUTION MODELS LIKE HRRR AND RUC13 HAVE
SLOWED THE CLEARING OF THE CLOUDS OVERNIGHT AND IF THIS VERIFIES
THEN FOG FORMATION IS LESS LIKELY LATER TONIGHT OVER CENTRAL IL.
SCATTERED OUT MID LEVEL CLOUDS BETWEEN 10Z-15Z AND BRING MVFR VSBYS
OF 3-5 MILES WITH FOG AT PIA WHICH IS SOONER TO SCATTER OUT. CLOUD
COVER CURRENLY FAIRLY EXPANSIVE UPSTREAM OVER CENTRAL/SOUTHERN IA
AND NORTHERN MO...SO DELAY IN CLEARING SEEMS REASONABLE. 1031 MB
HIGH PRESSURE OVER NW KS AND RIDGING INTO SE IA/NW IL WILL WEAKEN
TO 1026 MB AS IT SETTLES INTO CENTRAL IL DURING FRIDAY AFTERNOON
AND BRING FAIR WEATHER WITH JUST FEW- SCATTERED CUMULUS CLOUDS
MAINLY AT DEC AND CMI AND SCATTERED CIRRUS. CLEAR SKIES EXPECTED
BY FRIDAY EVENING. NNE WINDS OF 5-10 KTS OVERNIGHT WILL BECOME
LIGHT AND VARIABLY BY SUNSET FRIDAY.
KH
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT THU SEP 13 2012
THE OVERALL PATTERN FOR THE NEXT 7 DAYS WILL BE FAVORABLE FOR
COOLER THAN NORMAL TEMPS WITH PERIODIC RAINFALL CHANCES. A
LONGWAVE TROUGH WILL DOMINATE THE UPPER LEVEL FLOW ACROSS EASTERN
CANADA AND THE GREAT LAKES/NORTHEASTERN CONUS. THAT WILL SET THE
STAGE FOR A SERIES OF WAVES ARRIVING ON NORTHWEST FLOW ALOFT. THE
FIRST PERIOD OF RAIN WILL BE TONIGHT INTO FRIDAY MORNING...THE
SECOND WILL BE MONDAY AND MONDAY NIGHT...WITH THE THIRD COMING
NEXT WED NIGHT INTO THURSDAY.
SHORT TERM...TONIGHT THROUGH SUNDAY.
THE COLD FRONT ARRIVING INTO NW IL THIS AFTERNOON IS BEING SLOWED
DOWN BY A SHORTWAVE LIFTING NORTH FROM TENNESSEE AND WESTERN
KENTUCKY INTO SOUTHEAST ILLINOIS. SHOWERS ARE FEW AND FAR BETWEEN
AT THE MOMENT...BUT RAIN SHOULD FILL IN THIS EVENING AS THE
COLD FRONT GETS AN ENHANCE BOOST OF LIFT FROM THE DPVA FROM THE
SHORTWAVE IN SOUTHEAST IL. WE KEPT OUR LIKELY POPS IN FOR THIS
EVENING EVERYWHERE...THEN CONFINED THE LIKELY POPS TO SOUTHEAST OF
I-55 AFTER MIDNIGHT. THE SLOWER NATURE OF THE FRONTAL PROGRESSION
LED US TO CONTINUE WITH SOME LOW CHANCE POPS SOUTHEAST OF I-70 AND
SLIGHT CHANCES UP TO PARIS/DANVILLE FOR FRIDAY MORNING. SOME LIGHT
FOG MAY DEVELOP NORTHWEST OF THE IL RIVER LATE TONIGHT IF ANY
CLEARING REACHES THAT AREA. THE SHORT RANGE MODELS ARE INDICATING
SOME CLEARING AFTER 3 AM...SO FOG POTENTIAL WILL NEED TO BE
WATCHED.
CLEARING SHOULD PROGRESS FROM NW TO SE ON FRIDAY AS HIGH PRESSURE
BUILDS INTO THE AREA. FORECAST SOUNDINGS SHOW MIXING HEIGHTS AND LOW
LEVEL TEMPS SUPPORTIVE OF BELOW NORMAL HIGHS...WITH READINGS IN THE
LOWER 70S ACROSS THE BOARD. NORTHERLY WINDS WILL ADD SOME CHILL TO
THE AIR AS WELL.
A PLEASANT WEEKEND IS ON TAP AS HIGH PRESSURE REMAINS IN CONTROL.
WEAK RIDGING AND HEIGHT RISES ALOFT WILL AID IN SLIGHT WARMING OF
HIGH TEMPS TO NEAR NORMAL FOR SATURDAY AND SUNDAY. HIGHS SHOULD
REACH NEAR NORMAL IN THE MID TO UPPER 70S BOTH DAYS...WITH PLENTY
OF SUNSHINE.
LONG TERM...MONDAY THROUGH THURSDAY.
MONDAY WILL FEATURE THE APPROACH OF THE NEXT COLD FRONT. THE
AVERAGE TIMING OF THE FRONT IN THE EXTENDED MODELS PUTS THE
RAINFALL INTO OUR NW COUNTIES BY MID MORNING ON MONDAY...AND
CONTINUING INTO MONDAY NIGHT...ESPECIALLY SE OF I-55.
A BREAK IN THE ACTION AND COOLER TEMPS ARE EXPECTED FOR TUESDAY.
THE GFS EVEN BRINGS THE 0C LINE AT 850MB INTO NORTH CENTRAL IL
TUESDAY AFTERNOON AND EVENING. THE ECMWF AND CANADIAN KEEP THE 0C
LINE IN WISCONSIN/MICH...SO WE ARE TAKING THAT WILL A GRAIN OF
SALT. HOWEVER...THE THEME WILL BE BELOW NORMAL TEMPS FOR TUE
NIGHT/WED AND INTO THURSDAY. THE NEXT QUICK SHORTWAVE/COLD FRONT
IS EXPECTED TO MOVE SE INTO OUR COUNTIES WED NIGHT. THE EC/GFS
BOTH INDICATE THIS FEATURE PRETTY CLOSELY...SO WE KEPT THE
ALLBLEND CHANCE POPS FOR THAT TIME FRAME.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
413 AM EDT FRI SEP 14 2012
.SHORT TERM...
PRIMARY POST FNTL RAIN BAND IN ASSOCN/W POTENT UPR TROUGH OVR NE MN
TEMPORARILY IN THE PROCESS OF DECAY ACRS NW IN ATTM AS UPR SPEED MAX
PULLS AWAY. HWVR UPSTREAM SAT OBS AND MOST RECENT RADAR DATA SHOW
INTENSIFICATION/EXPANSION OF SECONDARY AREA OF RAINFALL ACRS CNTRL
IL TIED TO SECONDARY UPR SPEED MAX WHICH 06Z RUC MODEL GUIDANCE
LOOKS TO HAVE A GOOD HANDLE ON. 00Z GUIDANCE OUTSIDE GFS MUCH FASTER
W/EWD EXIT OF PCPN BUT BASED ON RUC/GFS AND FURTHER SPC 4KM WRF WILL
MAKE SOME SIG CHGS TO HOLD ONTO PCPN ACRS ERN IN FOR A BIT LONGER
THROUGH 15Z. OTHERWISE SIG FNTL SURGE XPCD LTR TDA AS NRN STREAM SW
OPENS FURTHER AND ACCELERATES INTO WRN QB BY LT AFTN. THUS CWA WILL
SEE RAPID W-E CLRG AND SIG COLUMN DRYING AS DEEP SUBSIDENCE SOUTH OF
MID LVL TROUGH SPREADS SEWD. DEEP MIXING AND INSOLATION WILL OFFSET
EARLY LL CAA WING W/PRIOR GRIDDED MAX TEMPS CLOSE AND HELD.
COOL CANADIAN SFC RIDGE FOLLOWS TONIGHT W/IDEAL RADIATIONAL COOLING
XPCD. DEGREE OF DRYING XPCD THROUGH THIS AFTN WILL CURTAIL ANY LT
NIGHT FOG THREAT W/MINS SETTLING INTO THE LOW-MID 40S.
SFC RIDGE REMAINS ENTRENCHED ACRS THE AREA THROUGH SUN W/NO SENSIBLE
WX CONCERNS. XPC SEASONABLE TEMPS W/SLIGHT WARMING TREND THROUGH THE
WEEKEND.
&&
.LONG TERM...
SUNDAY THROUGH THURSDAY...THE UPPER LEVEL PATTERN OVER NORTH AMERICA
WILL BECOME MORE AMPLIFIED THIS PERIOD AS SEVERAL SHORT WAVE TROFS
MOVE RAPIDLY SOUTHEAST TOWARD THE GREAT LAKES REGION. THE 500 MB
ANALOGS...GFS OPERATIONAL RUN AND THE BULK OF THE GFS ENSEMBLES ALL
IN REASONABLE AGREEMENT WITH ONE ANOTHER THAT A LONG WAVE TROF WILL
BECOME ESTABLISHED OVER EASTERN NORTH AMERICAN AND EXTEND ACROSS THE
WESTERN GREAT LAKES REGION. THERE WILL BE BRIEF WARMUPS AHEAD OF EACH
INDIVIDUAL TROF...SO TIMING OF THESE SMALLER SYSTEMS WITHIN THE MAIN
TROF OUT SEVERAL DAYS A LITTLE TRICKY AT THIS POINT. HOWEVER...THE
ONGOING TIMING OF THE FIRST 2 WAVES APPEARS ON TRACK IN REGARD TO
THE LATEST MODEL RUNS MENTIONED ABOVE. HAVE MADE JUST SOME MINOR
CHANGES...KEEPING A CHANCE FOR RAIN MONDAY NIGHT AND AGAIN THURSDAY.
HAVE REMOVED RAIN CHANCES WEDNESDAY NIGHT TO TRY TO BECOME MORE
REPRESENTATIVE WITH THE FORECAST. AS FOR TEMPERATURES...THE GFS/MEX
APPEARS ON TRACK SUNDAY AND MONDAY...BUT THE GFS MEAN ENSEMBLE MOS
APPEARS TOO COOL WITH HIGHS. HOWEVER...THE MEAN ENSEMBLE MOS DOES
APPEAR ON TRACK TUESDAY THROUGH THURSDAY WITH HIGHS ONLY IN THE 60S.
&&
.AVIATION...
POST FNTL RAIN BAND IN THE PROCESS OF RESURGING THIS MORNING IN
ASSOCN/W SECONDARY UPR SPEED MAX PROGRESSING THROUGH BASE OF
POTENT UPR TROUGH ROTATING THROUGH NE MN. KFWA HAS REMAINED ON ERN
FRINGE OF MORE ISOLD ACTIVITY OVR NRN/NE IN BUT RAPID
EXPANSION/INTENSIFICATION OF ECHOES SEEN UPSTREAM WOULD DICTATE
EVENTUAL AMENDMENT TO CARRY A TEMPO MVFR VIS/CIG RESTRICTION
THROUGH AT LEAST 12Z GIVEN NOD TWD SLWR RUC/GFS IMPLIED RAIN BAND
PROGRESSION.
REGARDLESS RAPID W-E DRYING XPCD INTO THIS AFTN AS UPR TROUGH
OPENS AND ACCELERATES EWD INTO WRN QB BY EVENING. THUS OUTSIDE
BRIEF PD OF MVFR CONDS EARLY THIS MORNING...VFR CONDS XPCD THROUGH
THE REMAINDER OF THE TERMINAL FCST PD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK THROUGH LATE TONIGHT FOR INZ003.
MI...RIP CURRENT RISK THROUGH LATE TONIGHT FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T
AREA FORECAST DISCUSSION
NWS DES MOINES IA
331 AM CDT FRI SEP 14 2012
.SHORT TERM /TODAY/...
HIGH PRESSURE CONTINUES OVER SOUTHERN IOWA EARLY TODAY WITH A WEAK
AREA OF LOW PRESSURE IN EASTERN SOUTH DAKOTA...INDUCED BY A POTENT
H500 SHORT WAVE DROPPING SOUTH AND EAST AT THE BASE OF THE 500MB
WESTERLIES EARLY TODAY. WITH LITTLE MOISTURE LEFT ACROSS THE
NORTHERN PLAINS...LITTLE IMPACT FROM SHORT WAVE EXPECTED THIS
MORNING. MEANWHILE...THE EXITING SYSTEM OF YESTERDAY CONTINUES TO
BRING SOME HIGH CLOUDS TO SOUTHERN IOWA. TEMPS HAVE REACHED THE DEW
POINT AND FOG HAS DEVELOPED...BUT SO FAR...WIDESPREAD FOG NOT A
PROBLEM WITH THE CLOUD COVER. THE CLOUDS SOUTH WILL SLOWLY DEPART
THROUGH EARLY MORNING WHILE THE WEAK TROUGH AND SFC LOW APPROACH
FROM THE WEST. LIGHT SOUTHWEST WINDS ARE ANTICIPATED THROUGH MOST OF
THE DAY WITH LITTLE MIXING TAKING PLACE THROUGH THE AFTERNOON HOURS.
CONSEQUENTLY...A PLEASANT WARM AND DRY DAY IS EXPECTED WITH HIGHS IN
THE UPPER 70S TO NEAR 80. DEW POINTS WILL REMAIN IN THE 40S FOR THE
AFTERNOON KEEPING RH LEVELS FAIRLY LOW...BUT WITH LITTLE WIND
ANTICIPATED...THE FIRE DANGER WILL NOT BE AMPLIFIED TODAY EVEN WITH
LOWER RH VALUES THIS AFTERNOON. SKIES WILL REMAIN SUNNY THROUGH MOST
OF THE AFTERNOON ONCE THE EARLY MORNING CLOUDS DEPART.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
WEAK UPPER LEVEL NORTHWESTERLY FLOW WILL BE IN PLACE THROUGH THE
WEEKEND. SURFACE WINDS WILL BE SOUTHERLY...AND WITH APPROACHING WAA
FROM THE WEST AND GOOD CONDITIONS FOR MIXING...TEMPERATURES WILL WARM
THROUGH THE WEEKEND. A FRONTAL BOUNDARY WILL PUSH SE ACROSS THE
AREA SUNDAY NIGHT INTO MONDAY. AND HAVE KEPT POPS GOING...THOUGH
HAVE TRENDED A BIT SLOWER ON SE EXTENT FOR SUNDAY NIGHT WITH
PRECIPITATION FOCUSED BEHIND THE FRONT. HOWEVER...MODELS REMAIN
IN GOOD AGREEMENT WITH SPEED OF SYSTEM...PUSHING IT THROUGH THE
AREA QUICKLY...AND HAVE KEPT POPS OUT FOR MONDAY NIGHT...AS ANY
RAIN CHANCES WILL BE WELL TO THE EAST. THIS BOUNDARY IS ASSOCIATED
WITH A CANADIAN LOW PRESSURE SYSTEM...AND COLD CANADIAN AIR WILL
PUSH IN BEHIND THE FRONT. TEMPERATURES WILL COOL SIGNIFICANTLY
BEHIND THE BOUNDARY. NEWEST MODEL RUNS DROP H85 TEMPS OVER IOWA
ANOTHER 2C OR SO OVER PAST RUNS...WITH TEMPS INT HE SINGLE DIGITS.
HOWEVER...WARMER AIR WILL PUSH IN QUICKLY FROM THE WEST AHEAD OF
ANOTHER LOW PRESSURES SYSTEM PUSHES EASTWARD ACROSS CANADA.
THEREFORE...HAVE ONLY DROPPED TEMPS A FEW DEGREES FOR MONDAY NIGHT
THROUGH TUESDAY NIGHT IN THE EAST. WITH THIS SECONDARY LOW
PRESSURE SYSTEM FOR LATE IN THE PERIOD...COULD SEE ADDITIONAL
CHANCES FOR PRECIPITATION. HOWEVER...DO NOT HAVE MUCH CONFIDENCE
IN PRECIP CHANCES...AND HAVE CUT BACK ON POPS FOR WEDNESDAY AND
THURSDAY. LOOKS LIKE BEST FORCING AND MOISTURE WILL REMAIN MUCH
FURTHER NORTH...CLOSER TO CENTER OF LOW PRESSURE.
&&
.AVIATION...14/06Z
THIN LAYER OF HIGH CLOUDS REMAIN ACROSS THE SOUTHERN PORTION OF THE
STATE AND HAVE ALLOWED FOR FOG DEVELOPMENT ACROSS SOME AREAS IN THE
SOUTHEAST. KOTM LOOKS TO BOUNCE AROUND FROM MVFR TO LIFR VIS
OVERNIGHT AND LATEST HRRR MODEL RUN HAS 1/4SM BY AROUND 10Z. WITH
CURRENT OB AT LIFR...LIKELY WILL SEE IT DOWN MUCH SOONER. LOW
CONFIDENCE WITH FOG DEVELOPMENT ELSEWHERE WITH STILL EITHER TOO
STRONG OF WINDS OR NOT ENOUGH MOISTURE IN THE BOUNDARY FROM THE RAIN
LAST EVENING. KALO WOULD LIKELY SEE THE BEST POTENTIAL OF FOG.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...AWB
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1137 PM CDT THU SEP 13 2012
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
MID LEVEL DRY AIR ADVECTION CONTINUES TO PUSH INTO CENTRAL IOWA
THIS AFTERNOON AND HAS BEEN ERODING THE NORTHWEST EDGE OF THE
DEPARTING PRECIPITATION BAND. THIS PRECIPITATION WILL BE SOUTHEAST
OF THE FORECAST AREA BY 00Z. UPPER PV ANOMALY AND ASSOCIATED 500 MB
LOW...WILL DIVE SOUTHEAST THROUGH MINNESOTA AND INTO THE WESTERN
GREAT LAKES TONIGHT. IMPRESSIVE -26C 500 MB COLD CORE JUST NORTHEAST
OF WHERE THE 1.5 PV PRESSURE DIPS TO BELOW 500 MB THROUGH THAT
REGION. THE PRIMARY IMPACT WITH THIS SYSTEM WILL BE A FEW MID LEVEL
CLOUDS PASSING THROUGH OVER THE NORTHEAST. A WEAK SFC LOW REFLECTION
WILL MOVE SLOWLY SOUTHEAST OVERNIGHT AS WELL AND WILL HELP SWITCH
SFC WINDS TO LIGHT SOUTHERLY AND HELP KEEP THE VERY LOW DEWPOINTS
CURRENTLY OVER THE DAKOTAS AND MINNESOTA OUT OF THE STATE. THE COOL
START THIS EVENING ALONG WITH THE CLEARING SKIES AND LIGHT WINDS
WILL STILL ALLOW TEMPERATURES TO COOL QUICKLY JUST NOT AS MUCH AS IF
THE VERY DRY AIR WAS IN PLACE. PASSING MID LEVEL CLOUDS OVER THE
NORTHEAST WILL IMPACT DIURNAL TRENDS A BIT AND IF PERSIST LONG
ENOUGH...MAY KEEP LOWS UP A FEW DEGREES. OVERALL EXPECT LOWS IN THE
LOW TO MID 40S WITH A FEW UPPER 30S POSSIBLE OVER THE NISHNABOTNA
VALLEY AND NORTHWEST.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
MID LEVEL RIDGING WILL WORK INTO THE STATE ON FRIDAY...AS THE
SURFACE HIGH SLOWLY PUSHES EAST OF THE AREA. SOUTH/SOUTHWESTERLY
FLOW WILL DEVELOP ALONG THE BACKSIDE OF THE DEPARTING HIGH ON FRIDAY
AFTERNOON. THE 13/12Z NUMERICAL MODELS ALL DEPICTED HIGHER WINDS
WITHIN THE MIXED LAYER FRIDAY AFTERNOON...WHICH DESPITE THE RECENT
RAINFALL...FULL SUNSHINE ALONG WITH ENHANCED MIXING SHOULD AID IN
HIGHS REACHING THE UPPER 70S TO LOW 80S.
AFTER A RELATIVELY BENIGN AND MILD WEEKEND...A RATHER STRONG WAVE
AND ASSOCIATED COLD FRONT WILL APPROACH THE MIDWEST LATE SUNDAY
INTO MONDAY. MODELS ARE STILL STRUGGLING WITH THE EXACT
TRACK/TIMING OF THE DIGGING WAVE...WITH THE 13/12Z GFS DIGGING THE
WAVE ACROSS EASTERN NE WHILE THE 13/12Z EURO DIVES IT ACROSS
NORTHERN ILLINOIS. REGARDLESS OF THE EXACT TRACK...POSTFRONTAL
PRECIPITATION LOOKS LIKE A PRETTY GOOD BET ACROSS THE CWA AS STRONG
DYNAMIC FORCING AND MID LEVEL FRONTOGENESIS INTERACT WITH SUFFICIENT
MID/LOW LEVEL MOISTURE. MOST SOUNDINGS DEPICT AT LEAST SOME ELEVATED
INSTABILITY...SO HAVE KEPT ISOLATED THUNDERSTORMS IN THE FORECAST
WITH THE WAVE PASSAGE. NORTHWEST FLOW DEVELOPS BEHIND THE DEPARTING
SYSTEM FOR THE MIDDLE OF NEXT WEEK...WITH SEVERAL DISTURBANCES
DROPPING THROUGH THE FLOW WHICH MAY PROVIDE SOME SHOWERS FOR THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION 14/06Z...
THIN LAYER OF HIGH CLOUDS REMAIN ACROSS THE SOUTHERN PORTION OF THE
STATE AND HAVE ALLOWED FOR FOG DEVELOPMENT ACROSS SOME AREAS IN THE
SOUTHEAST. OTM LOOKS TO BOUNCE AROUND FROM MVFR TO LIFR VIS
OVERNIGHT AND LATEST HRRR MODEL RUN HAS 1/4SM BY AROUND 10Z. WITH
CURRENT OB AT LIFR...LIKELY WILL SEE IT DOWN MUCH SOONER. LOW
CONFIDENCE WITH FOG DEVELOPMENT ELSEWHERE WITH STILL EITHER TOO
STRONG OF WINDS OR NOT ENOUGH MOISTURE IN THE BOUNDARY FROM THE RAIN
LAST EVENING. ALO WOULD LIKELY SEE THE BEST POTENTIAL OF FOG.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
AVIATION...PODRAZIK
LONG TERM...DEITSCH
AREA FORECAST DISCUSSION
NWS WICHITA KS
1157 PM CDT THU SEP 13 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
PER RECENT OBSERVATIONAL AND MODEL TRENDS...RAIN AND LOW MVFR/HIGH
IFR CIGS SHOULD CONTINUE THROUGH ABOUT 08-10Z FOR KICT...AND
THROUGH ABOUT MID MORNING FOR KCNU...AS MID-LEVEL CONVERGENCE ZONE
SLOWLY SHIFTS SOUTHEAST. CIGS SHOULD RISE DRAMATICALLY AT KICT
ONCE THE PRECIPITATION SHIELD SHIFTS SOUTHEAST OF THE TERMINAL.
OTHERWISE...COULD SEE SCATTERED PRECIPITATION AND MVFR CIGS
ENCROACH ON KCNU-KICT ONCE AGAIN BY LATER FRIDAY
AFTERNOON/EVENING...AS LOW/MID LEVEL CONVERGENCE ZONE SHIFTS BACK
NORTH.
ADK
&&
.PREV DISCUSSION... /ISSUED 919 PM CDT THU SEP 13 2012/
UPDATE...
PER THE LATEST NAM...RUC AND HRRR MODELS...ANTICIPATING BEST RAIN
CHANCES SLOWLY SHIFTING INTO FAR SOUTHERN/SOUTHEAST KS AS THE
NIGHT PROGRESSES...AS 700-600MB CONVERGENCE ZONE SLOWLY SHIFTS
SOUTH OVERNIGHT. THINKING BEST CHANCES AFTER MIDNIGHT WILL BE
GENERALLY SOUTH OF A LINE EXTENDING FROM KINGMAN-WICHITA-EMPORIA.
THIS AREA WILL BE CO-LOCATED UNDERNEATH BEST ZONE OF UPPER
DIFFLUENCE. AREAS OF RAIN SHOULD CONTINUE TO LINGER THROUGH FRIDAY
MORNING...WITH CHANCES REMAINING ALONG OK/KS BORDER THROUGH
FRIDAY AFTERNOON. CONSEQUENTLY...FRIDAY TEMPERATURES WILL ONCE
AGAIN BE COOLISH OVER FAR SOUTHERN KS.
ADK
PREV DISCUSSION... /ISSUED 643 PM CDT THU SEP 13 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
A RAINY AND CLOUDY 12-18 HOURS IS ANTICIPATED FOR PRIMARILY KICT
AND KCNU...WITH KHUT ON THE NORTHERN FRINGE OF THE
PRECIPITATION/CLOUDS...AS A MID-LEVEL CONVERGENCE ZONE REMAINS
NEARLY STATIONARY OVER THE REGION. THE ONLY CHANCE OF ISOLATED
THUNDER WILL BE FOR KCNU WHERE MARGINAL INSTABILITY WILL BE
PRESENT. OTHERWISE...PREVAILING VSBYS IN -RA WILL LIKELY BE
P6SM...WITH PERIODIC MVFR VSBYS IN RA. MVFR CIGS WILL PREVAIL AT
KICT-KCNU THROUGH THE PERIOD. ONLY HAVE PREVAILING VCSH AND
BKN030 AT KICT FROM 06Z ONWARD...ALTHOUGH MAY EVENTUALLY NEED TO
AMEND THIS TO INCLUDE PREVAILING -RA AND CIGS BELOW 2000 FT AGL
THROUGH AT LEAST THE PREDAWN HOURS. WILL CONTINUE TO MONITOR
TRENDS.
ADK
PREV DISCUSSION... /ISSUED 311 PM CDT THU SEP 13 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE IS THE PROGRESSION OF PRECIPITATION TODAY AND
TOMORROW AND THEN TEMPERATURES THROUGH SATURDAY.
SYNOPSIS:
THE UPPER WAVE HAS PROGRESSED EASTWARD WITH THE MAIN ENERGY LAGGING
A BIT BEHIND. PRECIPITATION CONTINUES AHEAD OF THE MAIN ENERGY
ACROSS THE EASTERN PORTIONS OF KANSAS THIS AFTERNOON. THE SURFACE
FRONT HAS CHARGED SOUTHWARD AND IS SITUATED FROM MISSOURI
SOUTHWESTWARD TO SOUTHWEST TEXAS. SCATTERED SHOWERS AND CLOUD COVER
IN ADDITION TO THE COLD AIR ADVECTION HAVE KEPT TEMPERATURES COOL
TODAY...WITH MOST LOCATIONS STAYING IN THE MID TO UPPER 50S TO LOW
60S.
TONIGHT - SUNDAY:
LIGHT SHOWERS WITH ISOLATED THUNDER WILL CONTINUE TO PROGRESS
SOUTHEASTWARD ACROSS THE AREA TONIGHT. THE UPPER ENERGY THAT IS
MOVING IN FROM NEW MEXICO WILL CONTINUE TO IMPACT THE REGION THROUGH
THE WEEKEND...CAUSING IT TO BE A LITTLE COOLER AND CLOUDIER THAN
PREVIOUSLY EXPECTED. AS THIS ENERGY TRANSLATES EASTWARD...THE LOWER
LEVELS WILL RESPOND WITH MOIST RETURN FLOW ACROSS EASTERN KANSAS.
EXPECT FRIDAY TO BE WARMER THAN TODAY...BUT STILL BELOW NORMAL WITH
HIGHS IN THE UPPER 60S TO 70S. THE WARMEST TEMPERATURES WILL BE
ACROSS CENTRAL KANSAS WHERE CLOUD COVER WILL BE MINIMAL AND
INSOLATION WILL BE GREATER. THE REAL QUESTION IS HOW FAR NORTH THE
CLOUD COVER WILL REMAIN THROUGH FRIDAY. EXPECTING THERE TO BE A
FINE LINE BETWEEN CLOUDY AND SUNNY. TEMPERATURES UNDER THE CLOUD
COVER AND POSSIBLE PRECIPITATION ARE EXPECTED TO BE IN THE 60S.
BOUNDARY LAYER MOISTURE IS EXPECTED TO CONTINUE TO SURGE NORTHWARD
ACROSS EASTERN KANSAS SATURDAY. THE CURRENT GUIDANCE
(NAM/GFS/ECMWF) INDICATES THAT MOST OF CENTRAL AND EASTERN KANSAS
WILL BE SOCKED IN UNDER LOW LEVEL CLOUDS. BECAUSE OF THIS HAVE
TRENDED COOLER FOR TEMPERATURES ON SATURDAY. FEEL THAT WIDESPREAD
TEMPERATURES IN THE 60S ARE NOT OUT OF THE QUESTION IF LOW CLOUDS
ARE PRESENT AS ADVERTISED.
CONFIDENCE ON PRECIPITATION THROUGH FRIDAY AND SATURDAY IS NOT
OVERLY HIGH...BUT FEEL THE CHANCES REMAIN FOR SCATTERED LIGHT
SHOWERS THROUGH MUCH OF THE DAY BOTH DAYS ACROSS EXTREME SOUTHERN
AND EASTERN KANSAS. EXPECTING SUNDAY TO WARM UP AND DRY OUT AS THE
UPPER ENERGY TRANSLATES MOSTLY EAST OF THE AREA.
MONDAY - THURSDAY:
THE NEXT WAVE WILL APPROACH FOR MONDAY AND WILL HELP KICK THE UPPER
ENERGY EAST THAT PLAGUED THE AREA FOR THE WEEKEND. THIS WAVE WILL
DRAG YET ANOTHER FRONT THROUGH DURING THE DAY MONDAY. THE GUIDANCE
DOES INDICATE THAT SOME PRECIPITATION WILL DEVELOP ALONG THE
FRONT...BUT CONFIDENCE ON THAT IS LOW. FEEL THE BEST CHANCES WILL
REMAIN EAST AS THE FRONT IMPACTS THE BETTER MOISTURE. TEMPERATURES
WILL AGAIN TAKE A HIT POST-FRONTAL AS SURFACE HIGH PRESSURE BUILDS IN.
A REINFORCING SHOT OF COLD AIR WILL PUSH THROUGH ON THURSDAY AS THE
NEXT PIECE OF ENERGY ROTATES AROUND THE UPPER TROUGH. THE EARLIER
FRONTS WILL HELP TO PUSH MOISTURE FROM THE AREA...AND THIS FRONTAL
PASSAGE IS LARGELY EXPECTED TO BE DRY.
BILLINGS
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
WIDESPREAD SHOWERS CONTINUE TO IMPACT MUCH OF SOUTH CENTRAL AND
CENTRAL KANSAS AND WILL SPREAD SLOWLY EAST-SOUTHEAST THROUGH THE
AFTERNOON. MVFR CIGS ARE EXPECTED TO PREVAIL FOR THE KICT/KHUT
TAF SITES FOR MOST OF THE DAYLIGHT HOURS. WILL SEE LOWER CIGS AND
LIGHT RAIN BEGIN TO IMPACT SOUTHEAST KANSAS AFTER 22Z. MVFR CIGS MAY
CONTINUE WITHIN AREAS OF LIGHT RAIN THROUGH MUCH OF THE NIGHT OVER
SOUTHEAST KANSAS WITH MORE UNCERTAINTY FURTHER WEST ACROSS SOUTH
CENTRAL KANSAS.
VFR CONDITIONS ARE EXPECTED TO RETURN TO CENTRAL KANSAS LATER THIS
AFTERNOON AS A SFC RIDGE OF HIGH PRESSURE BUILDS INTO THE AREA
SCOURING OUT THE LOW LEVEL MOISTURE.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 53 70 54 73 / 100 30 10 10
HUTCHINSON 52 71 51 74 / 40 10 10 10
NEWTON 52 72 53 72 / 70 20 10 10
ELDORADO 52 70 52 71 / 100 30 10 20
WINFIELD-KWLD 54 69 56 75 / 100 50 20 20
RUSSELL 47 73 48 75 / 0 10 0 0
GREAT BEND 48 72 49 74 / 0 10 0 0
SALINA 48 74 50 73 / 0 10 0 10
MCPHERSON 51 72 51 74 / 30 10 0 10
COFFEYVILLE 56 67 59 70 / 90 50 20 30
CHANUTE 54 70 56 70 / 90 50 20 20
IOLA 54 70 56 70 / 80 40 20 20
PARSONS-KPPF 55 68 56 70 / 80 50 20 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
122 AM EDT FRI SEP 14 2012
.SYNOPSIS...
ISSUED AT 427 PM EDT THU SEP 13 2012
A COLD FRONT WILL BRING RAIN TO THE AREA OVERNIGHT. THIS WILL BE
FOLLOWED BY COOLER BUT STILL SEASONABLE TEMPERATURES AROUND 70 ON
FRIDAY. AFTER A GRADUAL WARMING TREND TO THE MID 70S THROUGH
MONDAY...ANOTHER COLD FRONT WILL BRING A CHANCE FOR RAIN SHOWERS
MONDAY NIGHT AND TUESDAY ALONG WITH HIGH TEMPERATURES IN THE 60S.
&&
.UPDATE...
ISSUED AT 121 AM EDT FRI SEP 14 2012
UPDATE TO CANCEL THE REMAINDER OF THE SCA.
UPDATE ISSUED AT 1025 PM EDT THU SEP 13 2012
UPDATE TO EXPIRE SCA NORTH OF GRAND HAVEN. ALSO TWEAKED POPS SLIGHTLY.
UPDATE ISSUED AT 424 PM EDT THU SEP 13 2012
FORECAST WAS UPDATED TO ACCOUNT FOR THE SHOWERS DEVELOPING FROM
LANSING TO NEAR KALAMAZOO.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 335 PM EDT THU SEP 13 2012
TREND ON THE RAIN FOR TONIGHT HAS BEEN DOWN IN TERMS OF AMOUNTS FOR
SEVERAL MODEL RUNS NOW. REGIONAL RADAR LOOPS DO NOT LOOK OVERLY
IMPRESSIVE EITHER. STILL...EXPECT A BAND OF RAIN TO WORK THROUGH THE
ENTIRE FORECAST AREA BRINGING AMOUNTS ON THE ORDER OF A TENTH OR TWO
AT MOST LOCATIONS. THE FAR SOUTHEAST TOWARD JACKSON MAY SEE SLIGHTLY
HIGHER AMOUNTS. PRECIPITATION IS BEING FOCUSED BY THE RIGHT ENTRANCE
REGION OF A 300MB JET. CURRENT THINKING BASED ON SPC AND NSSL WRF
MODEL RUNS AND THE TRENDS IN THE LATEST HRRR IS THAT THE RAIN WILL
BE OFF TO THE EAST OF THE FORECAST AREA BY 12Z ON FRIDAY.
LOOKING FOR SOME MORNING CUMULUS DEVELOPMENT ON FRIDAY WITH DRIER
AIR TAKING OVER DURING THE AFTERNOON. IN GENERAL EXPECTING A PARTLY
CLOUDY TO MOSTLY SUNNY FORECAST FOR FRIDAY. FEEL THE AIR MASS
WILL BE TOO DRY FOR ANY SHOWER DEVELOPMENT OFF THE LAKE DESPITE
DELTA T/S IN THE MIDDLE TEENS C.
FRIDAY NIGHT THROUGH SATURDAY NIGHT LOOKS QUIET AND DRY WITH HIGH
PRESSURE IN CONTROL.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 335 PM EDT THU SEP 13 2012
FAIR WX WITH SEASONABLY MILD TEMPS IS ANTICIPATED SUNDAY THROUGH
MONDAY AFTERNOON IN A SOUTHERLY FLOW WAA PATTERN IN ADVANCE OF THE
APPROACHING COLD FRONT. THAT FRONT WILL BRING SOME SHOWERS MONDAY
NIGHT THROUGH TUESDAY. LAKE EFFECT CLOUDS AND SHOWERS ARE
ANTICIPATED TUESDAY NIGHT INTO WEDNESDAY AS H8 TEMPS (BRIEFLY) DIP
DOWN TO AROUND 0 TO -1 C BEFORE MODERATING.
IT WILL TURN COOLER TUESDAY THROUGH MIDWEEK AS A FAIRLY DEEP
LONGWAVE UPPER LEVEL TROUGH DEVELOPS FROM THE UPPER MIDWEST TO GREAT
LAKES REGIONS. A SECONDARY COLD FRONT WILL BRING THE CHANCE FOR
ADDITIONAL SHOWERS WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1153 PM EDT THU SEP 13 2012
LOW LEVEL MOISTURE ASSOCIATED WITH THE BAND OF RAIN MOVING THROUGH
HAS CREATED SOME IFR ROUGHLY KLAN TO KAZO...EAST. WITH THE BAND OF
RAIN ADVANCING EAST...THERE STILL COULD BE SOME IFR THROUGH ABOUT 09Z.
CLEARING BEHIND THE RAIN BAND...MAY ALLOW FOR GROUND FOG TO
FORM...BUT DRIER AIR WAS WORKING IN...SO NOT CONFIDENT ON THIS AT
THIS TIME. WILL MONITOR TRENDS IN THE NEXT FEW HRS.
MIXING ON FRI WILL ALLOW FOR SOME GUSTY WINDS...ESPECIALLY KGRR TO KMKG
&&
.MARINE...
ISSUED AT 335 PM EDT THU SEP 13 2012
HAVE OPTED TO KEEP THE CURRENT CONFIGURATION TO THE SMALL CRAFT
ADVISORIES WITH THE NORTH ENDING THIS EVENING AND THE SOUTH
OVERNIGHT. GRADIENT TURNS LAX TONIGHT IN THE WAKE OF FIRST FRONTAL
PASSAGE WHICH LEADS TO A DECAYING WAVE FIELD. WINDS INCREASE AGAIN
ON FRIDAY THOUGH IN THE WAKE OF A SECONDARY FRONT LATE TONIGHT.
WINDS WILL LIKELY NOSE UP TOWARDS 20 KNOTS FRIDAY WHICH SHOULD BUILD
A SOLID 3-5 FOOT WAVE FIELD DURING THE DAY. SO...RATHER THAN STRETCH
THE CURRENT SCA THROUGH TOMORROW THROUGH A 8-12 PERIOD OF QUIET
WAVES LATE TONIGHT AND TOMORROW MORNING OPTED TO LET THE CURRENT
HEADLINES EXPIRE TONIGHT. A NEW SCA WILL LIKELY BE NEED FOR FRIDAY
WITH THE OVERNIGHT FORECAST PACKAGE IF THE CURRENT FORECAST WINDS
HOLD.
&&
.HYDROLOGY...
ISSUED AT 335 PM EDT THU SEP 13 2012
NO HYDRO ISSUES ANTICIPATED WITH RAINFALL AMOUNTS PROBABLY ENDING UP
BELOW A THIRD OF AN INCH IN MANY AREAS TONIGHT. HIGHEST AMOUNTS WILL
BE IN THE FAR SOUTHEAST REACHES OF THE FORECAST AREA TOWARDS
JACKSON. RIVER LEVELS ARE LOW AND WELL WITHIN BANK. THE NEXT CHANCE
FOR RAIN DOES NOT COME UNTIL EARLY NEXT WEEK AFTER TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JK
SYNOPSIS...TJT
SHORT TERM...DUKE
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 PM CDT THU SEP 13 2012
.UPDATE...
ISSUED AT 901 PM CDT THU SEP 13 2012
WATCHING RADAR RETURNS DRY UP OVER CENTRAL AND WESTERN MISSOURI
ATTM. AM UNSURE YET HOW THIS WILL ALL UNFOLD DURING THE OVERNIGHT
HOURS THOUGH...RAP AND HRRR ARE SHOWING THAT THE PRECIP CURRENTLY
OVER EASTERN KANSAS WILL SPREAD EASTWARD OVER THE NEXT FEW HOURS
TO FILL IN BEHIND THE DRYING IN CENTRAL MO...AND CURRENT RADAR
TRENDS OVER EASTER KANSAS ARE STARTING TO SUPPORT THIS IDEA.
ADDITIONALLY...THE BRAND SPANKING NEW 14/00Z NAM IS ROLLING IN AND
IS INDICATING MORE OR LESS THE SAME THING. WILL GO AHEAD AND BUMP
UP POPS AFTER MIDNIGHT ALONG AND SOUTH OF THE I-70 CORRIDOR...AND
LINGER PRECIP INTO FRIDAY MORNING FROM THE STL METRO AREA SOUTH
AND EAST.
ISSUED AT 604 PM CDT THU SEP 13 2012
AM RECONFIGURING POPS FOR TONIGHT...INCREASING TO CATEGORICAL IN
THE NORTHEAST MO/WEST CENTRAL IL FOR THE FIRST FEW HOURS OF THE
FORECAST BASED ON RADAR TRENDS...AND DROPPING LIKELY POPS ACROSS MUCH
OF THE REST OF THE AREA THIS EVENING. ALL MODELS SHOW SOME DECENT
ISENTROPIC LIFT AS THE LOW LEVEL BAROCLINIC ZONE SLIPS SOUTHEAST
BEHIND THE FRONT SO WILL MARCH LIKELY POPS SLOWLY SOUTHEAST
THROUGH THE EVENING HOURS. 18Z NAM DROPS SOME PRETTY DECENT 925-850MB
FRONTOGENESIS DOWN THROUGH EASTERN MISSOURI AND SOUTHWEST ILLINOIS
OVERNIGHT BETWEEN 09Z AND 12Z FRIDAY MORNING SO WILL CONTINUE TO
MARCH THE LIKELIES SOUTHEAST THROUGH THE OVERNIGHT HOURS.
CARNEY
&&
.SHORT TERM...
ISSUED AT 308 PM CDT THU SEP 13 2012
(TONIGHT)
THE PRIMARY FCST ISSUES FOR TONIGHT ARE TEMPERATURE AND PCPN TRENDS.
A CDFNT WAS MOVING THROUGH MISSOURI AND ILLINOIS THIS AFTN WITH
EXTENSIVE CLOUDINESS AND SCT SHRA LOCATED BEHIND IT. A MARKED
TEMPERATURE CONTRAST WAS NOTED ACROSS THE FRONT AT 19Z WITH LOW TO
MID 80S IN THE MOSTLY CLEAR AREAS AHEAD OF THE BDRY AND LOW 50S TO
LOW 60S BENEATH THE POST-FRONTAL CLOUD SHIELD.
THE KEY FEATURE GOVERNING OVERNIGHT LOWS WILL BE THE DURATION /AND
HEIGHT/ OF CLOUD COVER. LOW-MID CLOUDS THAT PERSIST FOR MOST OF THE
NIGHT WOULD SUPPORT LESS OF A TEMPERATURE DROP THAN WOULD THINNER
CIRRUS OR CLR SKIES. CONDENSATION PRESSURE DEFICIT PLOTS FOR VARIOUS
LAYERS BETWEEN 850MB AND 500MB SUPPORT THE IDEA THAT ALL BUT THE FAR
NWRN PART OF THE CWA WILL REMAIN CLOUDY OVERNIGHT THEREFORE KEPT THE
COOLEST OVERNIGHT LOWS IN THE NWRN CWA.
ASIDE FROM A STRAY SPRINKLE OR TWO...NEARLY ALL OF THE PCPN HAS BEEN
POST-FRONTAL IN NATURE AND FREE OF LIGHTNING. ATTM IT LOOKS LIKE THE
AREA OF POST-FRONTAL SHRA SHOULD SLOWLY SHIFT SEWD WITH TIME BASED
ON MODEL DEPICTIONS OF H9/H85 FRONTOGENETICAL FORCING WITH LIMITED
INSTABILITY.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 309 PM CDT THU SEP 13 2012
(FRIDAY THROUGH THURSDAY)
WILL SEE SOME LINGERING LIGHT RAIN SHOWERS OVER SOUTHEAST MO AND
SOUTHERN IL AS SYSTEM EXITS REGION ON FRIDAY MORNING. WITH COOLER
AND DRIER AIR FILTERING IN TEMPS WILL STRUGGLE TO WARM UP MUCH.
HIGHS WILL BE IN THE LOW TO MID 70S...WITH THE COOLEST TEMPS SOUTH
DUE TO LINGERING CLOUD COVER IN THIS AREA.
FOR THE WEEKEND...A TRICKY FORECAST AS MOST MODELS NOW TRYING TO
DEVELOP SOME OVER RUNNING PCPN OVER SOUTHWESTERN MO ALONG OLD COLD
FRONTAL BOUNDARY LATE SATURDAY THROUGH SUNDAY. FOR NOW CONFIDENCE IS
LOW...SO JUST HAVE SLIGHT CHANCE POPS FOR FAR SOUTHWESTERN PORTIONS
OF FORECAST AREA SATURDAY NIGHT AND SUNDAY. AS FOR TEMPS...LOWS
FRIDAY NIGHT WILL BE IN THE UPPER 40S TO MID 50S. HIGHS THROUGH THE
WEEKEND WILL BE IN THE MID TO UPPER 70S.
BY LATE SUNDAY NIGHT...NEXT COLD FRONT BEGINS TO MOVE INTO MO. WILL
SEE FRONT MOVE INTO FORECAST AREA MONDAY WITH SOME DECENT
INSTABILITY AND MOISTURE...SO HAVE SHOWERS AND THUNDERSTORMS
POSSIBLE THROUGH MONDAY EVENING...BEFORE PCPN TAPERS OFF TOWARDS
DAYBREAK ON TUESDAY. HIGHS WILL BE IN THE MID TO UPPER 70S ON
MONDAY...BEFORE DROPPING OFF INTO THE MID 60S FAR NORTH TO THE LOW
70S FAR SOUTH ON TUESDAY. COLDEST NIGHT WILL BE TUESDAY NIGHT WITH
LOWS IN THE LOW TO MID 40S.
BEYOND THAT EXTENDED MODELS BRING IN ANOTHER COLD FRONT WEDNESDAY
NIGHT AND THURSDAY WITH ANOTHER CHANCE FOR SHOWERS.
BYRD
&&
.AVIATION...
ISSUED AT 1135 PM CDT THU SEP 13 2012
CDFNT AT 04Z HAS CLEARED THE ENTIRE FA AND CONTINUES TO BE
IDENTIFIED CLEARLY VIA FINE LINE ON RADAR MOSAIC. MVFR CIGS ARE
EDGING INTO THE STL METRO AREA AT THIS TIME AND EXTEND BACK TO THE
AXIS OF LIGHT RAIN NEAR KUIN-KCOU. POCKETS OF IFR CIGS CONTINUE TO
EXIST AS WELL. NNE FLOW AT 1-2KFT WILL GRADUALLY VEER TO A MORE
SOLID NE BY EARLY FRIDAY MORNING AND THIS SHOULD RESULT IN LO CIGS
BECOMING MORE STAGNANT AROUND THE STL METRO AREA FOR A PERIOD
FRIDAY MORNING...WHILE THIS MAIN AREA OF LO CLOUD SHOULD BE READY
TO CLEAR OUT OF KCOU SOON AS IT HAS ALREADY DONE AT KUIN. STILL
RATHER SOLID BAND OF LIGHT RAIN WELL BEHIND THE FRONT FROM CNTRL
IL SWWD THRU MID-MISSOURI AND INTO SERN KS...WHILE THINNING AS
EXPECTED ON ITS ERN FLANK...HAS BEEN RE-INVIGORATED BY UPSTREAM
WAVE IN THE W...AND SHOULD KEEP THE -RA...AROUND CNTRL MO
ESPECIALLY...A BIT LONGER. THIS RE-INVIGORATION SHOULD ALSO SERVE
TO GIVE STL METRO A SPOT OF RAIN TOWARD DAYBREAK AS WELL. LO CIGS
ARE THEN EXPECTED TO CLEAR OUT OF STL METRO BY LATE FRIDAY
MORNING LEAVING BEHIND A STILL EXPANSIVE REGION OF HI CLOUDS.
SPECIFICS FOR KSTL...N SFC WNDS TO GRADUALLY VEER NE FOR FRIDAY
AND THEN E AND VERY LIGHT FOR FRIDAY NIGHT...EXPECTED ARRIVAL OF
LO CLOUDS FROM THE N TOWARDS MIDNIGHT IS IMMINENT...WITH
PERSISTENCE LIKELY THRU MID FRIDAY MORNING...HAVE ADDED IN A
PERIOD OF IFR AROUND 12Z WITH IT MORE PROBABLE NOW BASED ON
UPSTREAM OBS...A PERIOD OF LIGHT RAIN EXPECTED AROUND DAWN...
IMPROVEMENT TO VFR THEN EXPECTED BY MIDDAY IF NOT SOONER.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
120 AM EDT FRI SEP 14 2012
.SYNOPSIS...
HIGH PRESSURE SLIPPING OFF THE MID-ATLANTIC COASTLINE WILL CONTINUE
FAIR WEATHER FOR ONE MORE NIGHT ACROSS THE REGION. A COLD FRONT WILL
SLIDE ACROSS THE REGION ON FRIDAY ALONG WITH SOME SHOWERS. BEHIND
THE COLD FRONT...SEASONABLY COOLER AIR WILL OVERSPREAD THE AREA FOR
THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
THROUGH LATE EVENING...WESTERN NEW YORK WAS MAINLY CLEAR...WITH
MID AND HIGH CLOUDS JUST WORKING IN TO FAR WESTERN PORTIONS OF THE
STATE. THIS CLOUD COVER SHOULD GRADUALLY MOVE FROM WEST TO EAST
OVERNIGHT. RADAR SHOWS A FEW LIGHT SHOWERS ACROSS CENTRAL LAKE
ERIE...AHEAD OF THE FRONT. MEANWHILE...A COLD FRONT WAS JUST
ENTERING FAR WESTERN PORTIONS OF LAKE ERIE AT 1100 PM. THE FRONT
ITSELF STILL IS DRY...BUT IT MAY PICK UP THE MOISTURE AND SHOWERS
STREAMING ACROSS CENTRAL LAKE ERIE. THE HRRR AND 18Z NAM HAS THIS
CLIPPING PERHAPS NIAGARA COUNTY DURING THE EARLY MORNING
HOURS...WHICH SEEMS REASONABLE.
ON FRIDAY THE COMPACT SHORTWAVE WILL BE DIGGING SOUTHWARD OVER THE
WESTERN GREAT LAKES. NEAR THE SURFACE A COLD FRONT WILL BE
CROSSING THE REGION FROM WEST TO EAST. RADAR CONFIRMS MODEL
FORECASTS OF AN ANAFRONTAL PASSAGE TO THE COLD FRONT WITH THE
BULK OF THE MOISTURE BEHIND THE FRONT WITH THE POTENT UPPER LEVEL
SHORTWAVE PROVIDING THE LIFT. RADAR SHOWS A SOLID LINE OF RAIN
SHOWERS...AND THE HRRR HOLDS THIS TOGETHER...BOTH OF WHICH
INCREASES CONFIDENCE IN AT LEAST SOME MEASURABLE PRECIPITATION
BEHIND THIS FRONT. BASED ON THIS...THE LATE EVENING UPDATE UPS
POPS...AND NUDGES TIMING BACK JUST A TAD. EXPECT A BAND OF CLOUDS
AND A NARROW BAND OF SHOWERS TO CROSS THE REGION...EARLY AFTERNOON
IN WESTERN PORTIONS...MID-AFTERNOON ACROSS THE GENESEE VALLEY AND
LATE AFTERNOON IN THE EASTERN LAKE ONTARIO REGION. IT IS POSSIBLE
THAT SOME CLEARING REACHES WNY TOWARD SUNSET. THIS CLEARING MAY
BE SHORT LIVED SOUTH OF LAKE ONTARIO AS COOLER AIR CONTINUES TO
POUR OVER THE EASTERN GREAT LAKES ON A NORTHWEST FLOW WITH PATCHY
LOW LEVEL STRATUS RETURNING ON FAVORABLE UPSLOPE AREAS SOUTH OF
LAKE ONTARIO EARLY EVENING.
THOUGH THERE HAS BEEN NO LIGHTNING ASSOCIATED WITH THESE SHOWERS
UPSTREAM TODAY...WILL CONTINUE TO MENTION SLIGHT CHC FOR THUNDER AS
MODELS DEPICT AN INCREASE IN INSTABILITY FRIDAY WITH UPWARDS TO 500
J/KG OF SBCAPE.
WITH THE PROGRESSIVE NATURE OF THIS COLD FRONT EXPECT QPF TO
GENERALLY BE A TENTH OR LESS TOWARDS THE SOUTH...WHILE FARTHER NORTH
ACROSS THE NORTHERN NIAGARA FRONTIER AND EASTERN LAKE ONTARIO
REGION UPWARDS OF TWO TENTHS OR SO OF AN INCH OF RAIN MAY FALL FRIDAY.
TEMPERATURES TONIGHT WILL COOL INTO THE MID AND UPPER 50S TOWARDS
THE GENESEE VALLEY AND AREAS EAST UNDER THE MAINLY CLEAR
SKIES...WHILE AREAS TO THE WEST WILL FAVOR 60 OR ABOVE AS CLOUDS
INCREASE. ON FRIDAY WITH THE COLD FRONT ACROSS WNY IN THE
MORNING...EXPECT THE WARMEST AREAS TO BE ACROSS THE EASTERN LAKE
ONTARIO REGION WHERE A FEW 80S WILL BE FOUND UNDER +13 TO +14C AT
850 HPA. TO THE WEST HIGHS WILL GENERALLY BE IN THE LOW AND MID
70S.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
COLD FRONT SHOULD BE EAST OF THE AREA FRIDAY NIGHT. SHARP MID LEVEL
DRY INTRUSION WILL PUSH INTO THE AREA IN WAKE OF THE FRONT...AS WELL
AS A MUCH COOLER AIR MASS. OVER-LAKE INSTABILITY WILL CERTAINLY BE
INCREASING THROUGH THE NIGHT AND EARLY SATURDAY...AS 850 MB
TEMPERATURES DROP TO NEAR +5C OR MAYBE A BIT COLDER. LINGERING LOW
LEVEL MOISTURE AND CYCLONIC FLOW MAY BE ABLE TO OVERCOME ENTRAINMENT
OF MID LEVEL DRY AIR TO DEVELOP SOME MINIMAL LAKE RESPONSE SOUTHEAST
OF LAKE ONTARIO...BUT ANYTHING THAT DOES DEVELOP SHOULD BE SHORT
LIVED AND LIGHT IN NATURE.
HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR FAIR WEATHER WEEKEND.
THE AIR MASS LOOKS QUITE DRY...THEREFORE EXPECT A LARGE DIURNAL
TEMPERATURE SWING. FAVORABLE RADIATIONAL COOLING CONDITIONS SATURDAY
NIGHT/SUNDAY MORNING WILL ALLOW TEMPERATURES TO DROP INTO THE MID TO
UPPER 30S INLAND. THIS WILL BRING A POTENTIAL FROST TO SOME
LOCATIONS ALONG THE SOUTHERN TIER AND EAST OF LAKE ONTARIO.
SATURDAY LOOKS TO BE THE COOLEST WEEKEND DAY WITH MOST HIGHS IN THE
MID TO UPPER 60S. WARM AIR ADVECTION DEVELOPS BY SUNDAY AS THE HIGH
STARTS TO SHIFT EAST...THIS SHOULD ALLOW TEMPERATURES TO REBOUND
BACK INTO THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
SOME MODEL DISCREPANCIES DEVELOP BY MONDAY. THE GFS IS MUCH
FASTER THAN THE ECMWF/CANADIAN WITH THE SHORTWAVE ENERGY LIFTING
OUT OF THE SOUTHERN PLAINS...WHILE SLOWER SOLUTIONS ALLOWS FOR
SOME PHASING OF NORTHERN AND SOUTHERN STREAM WAVES. AT THIS
POINT...WILL OFFER A MODEL BLEND AND BRING SOME LIMITED
PROBABILITIES INTO THE AREA AHEAD OF THE COLD FRONT FOR MONDAY.
THE UPPER LEVEL FLOW LOOKS TO BECOME DEEPLY AMPLIFIED HEADING INTO
THE MIDDLE OF NEXT WEEK...WITH AN IMPRESSIVE WESTERN CONUS RIDGE AND
CENTRAL PLAINS/GREAT LAKES TROUGH EVOLVING. LATEST MEDIUM RANGE
MODELS AND ENSEMBLES IN GENERAL AGREEMENT BRINGING SHARP COLD FRONT
LATER TUESDAY INTO WEDNESDAY. DECENT POTENTIAL FOR SHOWERS WITH THE
FRONTAL PASSAGE FOLLOWED BY A SHOT OF RATHER CHILLY AIR. THERE LOOKS
TO BE SOME AIRMASS MODIFICATION...BUT WEDNESDAY STILL COULD BE
RATHER COOL WITH SOME LOCATIONS STRUGGLING TO GET OUT OF THE 50S.
PATTERN LOOKS PROGRESSIVE WITH WARM AIR ADVECTION PATTERN RESUMING
THURSDAY AHEAD OF NEXT APPROACH FRONTAL ZONE.
&&
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
THROUGH 12Z...VFR CONDITIONS WILL PREVAIL...WITH MID AND HIGH
CLOUD COVER GRADUALLY INCREASING FROM WEST TO EAST IN ADVANCE OF
A SLOWLY APPROACHING COLD FRONT. IN THE PREDAWN HOURS...A FEW
SCATTERED LIGHT SHOWERS WILL BE POSSIBLE ACROSS FAR WESTERN NEW
YORK IN ASSOCIATION WITH THE FRONT...HOWEVER EVEN IF THESE
MATERIALIZE THEY SHOULD HAVE NO IMPACT ON AVIATION CONCERNS.
DURING THE COURSE OF TODAY...THE AFOREMENTIONED FRONT WILL SLOWLY
CROSS THE REGION FROM WEST TO EAST...WITH A 3-4 PERIOD OF SHOWERS
AND ASSOCIATED MVFR CONDITIONS FOLLOWING ITS PASSAGE. THIS PERIOD
OF SHOWERS SHOULD BEGIN ACROSS THE FAR WESTERN TAF SITES AROUND
18Z...KROC AROUND 19Z...AND KART AROUND 21Z. WHILE A FEW EMBEDDED
THUNDERSTORMS ALSO CANNOT BE RULED OUT BEHIND THE FRONT...THE
PROBABILITY OF THESE APPEARS TOO LOW TO MENTION GIVEN ONLY LIMITED
AMOUNTS OF INSTABILITY.
FOLLOWING THE END OF THE FRONTAL PRECIP...THE COMBINATION OF
LINGERING LOW LEVEL MOISTURE AND LAKE INFLUENCES WILL KEEP A MIX
OF MVFR TO LOW VFR CIGS IN PLACE TONIGHT...WITH THE LOWEST CIGS
FOUND DOWNWIND /EAST-SOUTHEAST/ OF LAKES ERIE AND ONTARIO. WITH
INCREASING AMOUNTS OF LAKE-DRIVEN INSTABILITY...SOME SCATTERED
RAIN SHOWERS WILL ALSO BECOME POSSIBLE SOUTHEAST OF LAKE ONTARIO.
OUTLOOK...
SATURDAY...MVFR/VFR IN THE MORNING WITH SCATTERED SHOWERS
SOUTHEAST OF LAKE ONTARIO...THEN IMPROVING TO VFR.
SUNDAY AND MONDAY...VFR.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/ASSOCIATED MVFR.
&&
.MARINE...
HIGH PRESSURE SLIPPING OFF THE MID ATLANTIC COASTLINE WILL GIVE ONE
MORE QUIET NIGHT ON THE LAKES AND RIVERS. ON FRIDAY A COLD FRONT
WILL CROSS THE REGION FROM WEST TO EAST WITH A NARROW BAND OF
SHOWERS...PRIMARILY BEHIND THE FRONT. AS WINDS SHIFT TO NORTHWEST
AND WITH SHARP COOLING ALOFT EXPECT WAVES TO INCREASE LATER FRIDAY
AND FRIDAY NIGHT WITH SMALL CRAFT CONDITIONS ON CENTRAL AND EASTERN
PORTIONS OF LAKE ONTARIO. HAVE THEREFORE ISSUED A SCA FOR THESE
SECTIONS OF LAKE ONTARIO. WITH THE BOUNDARY LAYER FLOW MORE
PERPENDICULAR TO LAKE ERIE FRIDAY EVENING AND NIGHT WAVES WILL
INCREASE...THOUGH LIKELY REMAINING BELOW SMALL CRAFT CONDITIONS.
A STEADY NORTHWEST FLOW WILL CONTINUE TO START THE WEEKEND THOUGH
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA.
&&
.CLIMATE...
ALL THREE OF OUR CLIMATE SITES REACHED AT LEAST 80F THURSDAY. THIS
SAID...ALL THREE LOCATIONS CONTINUE TO RANK THIRD FOR GREATEST
NUMBER OF 80F DAYS IN A YEAR.
BUFFALO (SINCE 1944)
1 83 1949
2 82 1959
3 79 2012
AVG: 54 DAYS
ROCHESTER (SINCE 1871)
1 91 1959
2 86 2007
3 85 2012
AVG: 59 DAYS
WATERTOWN (SINCE 1949)
1 75 1949
2 73 1959
3 72 2012
AVG: 45 DAYS
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 AM EDT
SATURDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT
SATURDAY FOR LOZ045.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...JJR
MARINE...APFFEL/THOMAS
CLIMATE...THOMAS/JJR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CDT THU SEP 13 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY
313 PM CDT THU SEP 13 2012
MAIN FORECAST CONCERNS ARE FOG IN RIVER VALLEYS AND FROST POTENTIAL
TONIGHT...THEN TEMPERATURES FRIDAY THROUGH SUNDAY.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL LOW OVER
SOUTHERN MANITOBA AND SHORTWAVE TROUGH EMBEDDED IN THE
NORTHWESTERLY FLOW OVER CENTRAL NORTH DAKOTA. LATEST 19Z SURFACE
ANALYSIS INDICATING HIGH PRESSURE BUILDING INTO WESTERN IOWA AND
DRIER AIR BEGINNING TO ADVECT INTO WESTERN FORECAST AREA...WITH
DEWPOINTS FALLING INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS SOUTHERN
AND WESTERN MINNESOTA.
THE 13.12Z GFS/NAM ARE IN DECENT AGREEMENT WITH DEVELOPING ZONAL
FLOW ACROSS THE NORTHERN TIER STATES THIS WEEKEND. THE MOST
SIGNIFICANT DIFFERENCE BETWEEN THE DETERMINISTIC MODELS IS THE NAM
SLIGHTLY FARTHER SOUTH WITH SURFACE FRONT SUNDAY THAN THE GFS. THIS
WOULD PUSH THE MOISTURE CONVERGENCE AND LIFT ALONG THE FRONT INTO THE
NORTHERN FORECAST AREA. HOWEVER...FEEL THE NAM IS TOO FAR SOUTH AND
FOLLOW MORE TOWARDS THE GFS DURING THIS TIMEFRAME.
TONIGHT...THE DETERMINISTIC 13.12Z GFS/NAM AND 13.18Z RAP ARE PICKING
UP WEAK WARM AIR ADVECTION AT 700MB OUT AHEAD OF THE SHORTWAVE TROUGH
OVER CENTRAL NORTH DAKOTA AND PRODUCING MOISTURE IN THE 600-800MB
LAYER PER BUFKIT SOUNDINGS. THE MOISTURE IN THIS LAYER THE
DETERMINISTIC MODELS PROG INTO THE FORECAST AREA AFTER 03Z FRIDAY AND
WILL HAVE IMPACTS ON TEMPERATURES AND FOG POTENTIAL. AT THIS TIME...
UNCERTAINTY EXIST ABOUT FOG DEVELOPMENT IN THE MISSISSIPPI RIVER
VALLEY...AS THE 13.12Z DETERMINISTIC MODELS ARE IN AGREEMENT SOME MID
LEVEL CLOUDS WILL DRIFT OVER THE FORECAST AREA BETWEEN 03Z-09Z
TIMEFRAME. FOR NOW...HAVE KEPT PATCHY TO AREAS FOG IN RIVER VALLEYS.
TEMPERATURES WILL BE AFFECTED BY THE SCATTERED TO BROKEN MID LEVEL
DECK CLOUDS ESPECIALLY OVER SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THE 13.12Z DETERMINISTIC MODELS DISSIPATE MOISTURE/MID CLOUD DECK
OVER WESTERN/CENTRAL WISCONSIN AND TEMPERATURES ARE EXPECTED TO FALL
INTO THE MIDDLE 30S OVER PARTS OF CENTRAL WISCONSIN AND PRODUCE
ISOLATED SPOTS OF PATCHY FROST.
SURFACE RIDGE DOMINATES THE FORECAST AREA FRIDAY INTO SATURDAY
PROVIDING DRY WEATHER CONDITIONS. TEMPERATURES ARE EXPECTED TO
MODERATE AND BE SLIGHTLY ABOVE NORMAL BOTH DAYS...AS THE 13.12Z
DETERMINISTIC MODELS ADVECT SOME WARMER AIR INTO THE AREA.
SURFACE RIDGE BUILDS INTO THE OHIO RIVER VALLEY SATURDAY
NIGHT/SUNDAY AND SOUTHERLY WINDS ON THE BACKSIDE OF THE HIGH PRESSURE
SYSTEM AND ALOFT...WILL USHER IN LOW LEVEL MOISTURE FROM THE
SOUTHERN PLAINS STATES NORTHWARD INTO THE FORECAST AREA. THIS IS
EVIDENT IN THE 850MB TO 925MB RELATIVE HUMIDITY FIELDS PER 13.12Z
GFS/NAM. HAVE INCREASE SKY COVER SLIGHTLY SUNDAY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
313 PM CDT THU SEP 13 2012
MAIN FORECAST CONCERNS THROUGH THE PERIOD ARE PRECIPITATION CHANCES
AND TEMPERATURES. THE 13.12Z GFS/ECMWF/GEM ARE IN ALL PRETTY GOOD
AGREEMENT IN DIGGING UPPER LEVEL TROUGH OVER THE NORTHERN PLAINS AND
THE UPPER GREAT LAKES REGION THROUGH FORECAST PERIOD. BIGGEST
DIFFERENCE BETWEEN THE DETERMINISTIC MODELS IS TIMING OF THE
EMBEDDED SHORTWAVE TROUGHS IN THE NORTHERLY FLOW ALOFT. THIS WILL
HAVE IMPACTS ON TIMING OF PRECIPITATION CHANCES INTO THE FORECAST
AREA THROUGH THE FORECAST PERIOD. THE DETERMINISTIC 13.12Z
GFS/ECMWF/GEM CONTINUE TO SHOW COLDER AIR TO FILTER INTO THE AREA
WITH 850MB TEMPERATURES DROPPING TO AROUND ZERO DEGREES CELSIUS AT
12Z TUESDAY. THE 13.00Z GEFS INDICATE STANDARD ANOMALIES OF MINUS 1
TO MINUS 1.5 OVER THE FORECAST AREA MIDDLE OF NEXT WEEK.
TEMPERATURES WILL BE BELOW NORMAL THROUGH MUCH OF THE FORECAST
PERIOD WITH HIGH TEMPERATURES RISING INTO THE 50S TO 60S.
&&
.AVIATION...THROUGH 06Z SATURDAY
1148 PM CDT THU SEP 13 2012
AN UPPER LEVEL LOW OVER SOUTHWEST ONTARIO HAS A STRONG SHORT WAVE
TROUGH MOVING ACROSS NORTHWEST MINNESOTA. A DECK OF MID LEVEL
CLOUDS AHEAD OF THE SHORT WAVE TROUGH CONTINUES TO ADVANCE
SOUTHEAST TOWARD THE AREA AND WILL OVERSPREAD BOTH TAF SITES
SHORTLY AFTER 06Z. USING SATELLITE TO TIME THE BACK EDGE OF THE
CLOUDS...EXPECTING THEM TO REMAIN FOR MOST OF THE NIGHT CLEARING
OUT AROUND 12Z. THIS WILL BE LONG ENOUGH TO KEEP FOG FROM FORMING
AT KLSE AND HAVE REMOVED THIS FROM THE FORECAST. ONCE THE CLOUDS
CLEAR OUT...HIGH PRESSURE WILL BUILD IN FOR CLEAR SKIES AND LIGHT
WINDS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
313 PM CDT THU SEP 13 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....DTJ
LONG TERM......DTJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS MIAMI FL
1017 AM EDT FRI SEP 14 2012
.UPDATE...
WEAKER EASTERLY FLOW IS OCCURRING ACROSS THE REGION THIS
MORNING...AS THE SURFACE BOUNDARY HAS DRIFTED A LITTLE SOUTH IN
THE FLORIDA STRAITS AND SURFACE HIGH PRESSURE HAS WEAKENED DUE TO
A SHORTWAVE TROUGH MOVING ACROSS THE GREAT LAKES. ISOLATED TO
WIDELY SCATTERED SHOWERS HAVE DEVELOPED OVER THE ATLANTIC...MAINLY
EAST OF PALM BEACH COUNTY. THE 12Z SOUNDING SHOWED A THIN DRY
LAYER BETWEEN 700 AND 750MB...WITH STEEPER LAPSE RATES ABOVE THIS
INVERSION. SO THE MODIFIED SOUNDING SHOWS THERE IS A LITTLE MORE
POTENTIAL FOR WIND TODAY...BUT STILL ONLY THE TYPICAL 40-50 MPH IN
THE STRONGEST STORMS...AND THIS WILL MAINLY BE FOR THE INTERIOR
AND THE GULF COAST. WITH THE LIGHTER FLOW...ISOLATED TO LOW END
SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE FOR THE
EAST COAST AREAS THROUGH MID AFTERNOON. AFTER THAT TIME...A GULF
COAST SEA BREEZE SHOULD DEVELOP...WITH THE BULK OF THE ACTIVITY
FOCUSING IN THIS REGION. NO MAJOR UPDATES WERE NEEDED TO THE GOING
FORECAST.
&&
.PREV DISCUSSION... /ISSUED 744 AM EDT FRI SEP 14 2012/
AVIATION...
THE RIDGE OF HIGH PRESSURE EXTENDING SOUTHWEST INTO THE
SE U.S. BEGINS TO WEAKEN AND MOVE NORTHEAST AS A LOW PRESSURE SYSTEM
AND THE ASSOCIATED COLD FRONT MOVE TOWARD THE EAST U.S. COAST TODAY
INTO SATURDAY. WITH THE PRESSURE GRADIENT OVER SOUTH FLORIDA
WEAKENING...THE EASTERLY WIND FLOW WILL PERSIST TODAY INTO SATURDAY
BUT MUCH LOWER. CURRENTLY WIDELY SCATTERED SHRA MOVING WEST FROM THE
ATLC ONSHORE WITH VERY BRIEF MVFR CIG/VSBY AT ANY E COAST TERMINAL
BUT ONLY VCSH IN TAFS AT THIS TIME. AFT 15Z...ISOLD TSRA POSSIBLE
BUT SHOULD BE WEST OF TERMINALS SO NO VCTS IN TAFS. WINDS VARIABLE
TO ENE < 10 KNOTS BECOMING AFT 14Z 10-13 KNOTS WITH GUSTS TO THE
MID/UPPER TEENS. AT KAPF...VFR THROUGH PERIOD WITH VCSH AFT 18Z.
TSRA POSSIBLE BUT NOT IN TAF AT THIS TIME. SURFACE WIND CURRENTLY
NE < 10 KNOTS BECOMING 10 TO 12 KNOTS AFT 15Z.
PREV DISCUSSION... /ISSUED 200 AM EDT FRI SEP 14 2012/
SHORT TERM (TODAY-SUNDAY)...
THE LATEST NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT OVER THE
WEEKEND AND GENERALLY INDICATES LIGHT TO MODERATE EASTERLY FLOW
CONTINUING JUST NORTH OF A WEAK TROUGH OR WHAT IS LEFT OF THE
FRONTAL BOUNDARY THAT MOVED THROUGH A FEW DAYS AGO AND HIGH PRESSURE
TO THE NORTH. ALTHOUGH THE RAINFALL COVERAGE TODAY IS EXPECTED TO BE
LESS THAN YESTERDAY...SCATTERED SHOWERS OVER THE ADJACENT ATLANTIC
WATERS SPREADING ASHORE ACROSS PORTIONS OF THE EAST COAST AREAS
EARLY THIS MORNING WILL REMAIN POSSIBLE ONCE AGAIN. THIS LINES UP
WELL WITH THE LATEST HRRR AND WRF MODEL REFLECTIVITIES TODAY. FOR
THE AFTERNOON...EXPECT THIS ACTIVITY TO SPREAD INLAND AND BECOME
CONCENTRATED OVER THE INTERIOR AND WESTERN AREAS THROUGH THE EVENING
HOURS BEFORE DIMINISHING. THE EASTERLY FLOW HAS WEAKENED COMPARED TO
YESTERDAY...WHICH SHOULD ALLOW A WEST COAST SEA BREEZE TO BECOME
ESTABLISHED THIS AFTERNOON. THE MAIN IMPACTS FROM THIS
AFTERNOON/EVENING ACTIVITY WILL BE THE POTENTIAL FOR PERIODS WITH
HEAVY RAIN AND GUSTY WINDS WITH ANY STRONGER STORMS THAT DEVELOP.
HOWEVER...MODEL SOUNDINGS ARE NOT THAT IMPRESSIVE AND INDICATE
MEAGER MID-LEVEL LAPSE RATES WITH NEAR AVERAGE 500 MB TEMPERATURES.
OVER THE WEEKEND...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH
TEMPERATURES REMAINING NEAR OR AROUND NORMAL.
LONG TERM (SUNDAY NIGHT-THURSDAY)...
MODELS CONTINUE TO INDICATE UPPER HEIGHTS FALLING AHEAD OF A
SHORTWAVE TROUGH PROGGED TO TRANSLATE EAST THEN NORTHEAST ACROSS THE
REGION WELL NORTHWEST OF OUR LOCAL AREA SUNDAY THROUGH TUESDAY. THIS
SHORTWAVE COMBINED WITH ANOTHER POTENT PIECE OF ENERGY DIVING
SOUTHEAST OVER THE PLAIN STATES WILL QUICKLY AMPLIFY THE OVERALL
UPPER PATTERN ACROSS THE COUNTRY CHARACTERIZED WITH A DEEPENING
TROUGH OVER THE EASTERN STATES AND RIDGING OUT WEST. THE ATTENDANT
COLD FRONT ASSOCIATED WITH THE LEAD SHORTWAVE IS FORECAST TO SWEEP
EAST ACROSS THE REGION AND GENERALLY LAYOUT FROM EAST TO WEST AND
STALL JUST NORTH OF OUR LOCAL AREA SOMETIME AROUND THE MID-WEEK TIME
FRAME AS IT LOSES ITS UPPER SUPPORT. THE ECMWF AND GFS/GFS ENSEMBLE
MEAN SOLUTIONS APPEAR TO BE IN BETTER AGREEMENT WITH THIS BOUNDARY
SPATIALLY AND TEMPORALLY THROUGH THIS...WHEREAS...24 HRS AGO
INDICATED LARGER DIFFERENCES. IF THIS VERIFIES...EXPECT THE
LOW-LEVEL FLOW LOCALLY TO GRADUALLY VEER TO THE SOUTH AND SOUTHWEST
MONDAY THROUGH TUESDAY AS A WARM FRONT LIFTS NORTH OVER THE EASTERN
GULF AND FL. THE RESULTANT DEEP AND MOIST SOUTHWEST FLOW SHOULD
TRANSLATE TO HIGHER THAN NORMAL RAIN CHANCES...ESPECIALLY OVER THE
NORTH AND NORTHEASTERN SECTIONS OF THE FORECAST AREA FROM THE LAKE
TO PALM BEACH REGION. DUE TO THE BETTER AGREEMENT BETWEEN THE LATEST
MODEL GUIDANCE AND PERSISTENCE FROM RUN TO RUN...WILL SLIGHTLY
INCREASE THE RAINFALL PROBABILITIES MONDAY THROUGH THE MID-WEEK
PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS AND WILL PERSIST THROUGH THE
WEEKEND WITH SCATTERED SHOWERS AND STORMS POSSIBLE...ESPECIALLY
OVERNIGHT AND THROUGH THE EARLY MORNING HOURS ACROSS THE ATLANTIC
WATERS. SEAS WILL GRADUALLY TREND DOWN THROUGH THE WEEKEND TO
AROUND NORMAL. WINDS ARE FORECAST TO SHIFT SOUTH AND POSSIBLY
SOUTHWEST SOMETIME NEXT WEEK FROM MONDAY THROUGH WEDNESDAY AS
ANOTHER FRONTAL BOUNDARY APPROACHES AND STALLS NORTH OF THE MARINE
AREA.
FIRE WEATHER...
MOIST CONDITIONS WILL KEEP RH`S WELL ABOVE CRITICAL LEVELS THROUGH
THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 77 86 76 / 30 20 30 20
FORT LAUDERDALE 86 78 88 78 / 30 20 30 20
MIAMI 87 78 88 78 / 30 20 40 20
NAPLES 89 74 91 75 / 40 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
744 AM EDT FRI SEP 14 2012
.AVIATION...
THE RIDGE OF HIGH PRESSURE EXTENDING SOUTHWEST INTO THE
SE U.S. BEGINS TO WEAKEN AND MOVE NORTHEAST AS A LOW PRESSURE SYSTEM
AND THE ASSOCIATED COLD FRONT MOVE TOWARD THE EAST U.S. COAST TODAY
INTO SATURDAY. WITH THE PRESSURE GRADIENT OVER SOUTH FLORIDA
WEAKENING...THE EASTERLY WIND FLOW WILL PERSIST TODAY INTO SATURDAY
BUT MUCH LOWER. CURRENTLY WIDELY SCATTERED SHRA MOVING WEST FROM THE
ATLC ONSHORE WITH VERY BRIEF MVFR CIG/VSBY AT ANY E COAST TERMINAL
BUT ONLY VCSH IN TAFS AT THIS TIME. AFT 15Z...ISOLD TSRA POSSIBLE
BUT SHOULD BE WEST OF TERMINALS SO NO VCTS IN TAFS. WINDS VARIABLE
TO ENE < 10 KNOTS BECOMING AFT 14Z 10-13 KNOTS WITH GUSTS TO THE
MID/UPPER TEENS. AT KAPF...VFR THROUGH PERIOD WITH VCSH AFT 18Z.
TSRA POSSIBLE BUT NOT IN TAF AT THIS TIME. SURFACE WIND CURRENTLY
NE < 10 KNOTS BECOMING 10 TO 12 KNOTS AFT 15Z.
&&
.PREV DISCUSSION... /ISSUED 200 AM EDT FRI SEP 14 2012/
SHORT TERM (TODAY-SUNDAY)...
THE LATEST NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT OVER THE
WEEKEND AND GENERALLY INDICATES LIGHT TO MODERATE EASTERLY FLOW
CONTINUING JUST NORTH OF A WEAK TROUGH OR WHAT IS LEFT OF THE
FRONTAL BOUNDARY THAT MOVED THROUGH A FEW DAYS AGO AND HIGH PRESSURE
TO THE NORTH. ALTHOUGH THE RAINFALL COVERAGE TODAY IS EXPECTED TO BE
LESS THAN YESTERDAY...SCATTERED SHOWERS OVER THE ADJACENT ATLANTIC
WATERS SPREADING ASHORE ACROSS PORTIONS OF THE EAST COAST AREAS
EARLY THIS MORNING WILL REMAIN POSSIBLE ONCE AGAIN. THIS LINES UP
WELL WITH THE LATEST HRRR AND WRF MODEL REFLECTIVITIES TODAY. FOR
THE AFTERNOON...EXPECT THIS ACTIVITY TO SPREAD INLAND AND BECOME
CONCENTRATED OVER THE INTERIOR AND WESTERN AREAS THROUGH THE EVENING
HOURS BEFORE DIMINISHING. THE EASTERLY FLOW HAS WEAKENED COMPARED TO
YESTERDAY...WHICH SHOULD ALLOW A WEST COAST SEA BREEZE TO BECOME
ESTABLISHED THIS AFTERNOON. THE MAIN IMPACTS FROM THIS
AFTERNOON/EVENING ACTIVITY WILL BE THE POTENTIAL FOR PERIODS WITH
HEAVY RAIN AND GUSTY WINDS WITH ANY STRONGER STORMS THAT DEVELOP.
HOWEVER...MODEL SOUNDINGS ARE NOT THAT IMPRESSIVE AND INDICATE
MEAGER MID-LEVEL LAPSE RATES WITH NEAR AVERAGE 500 MB TEMPERATURES.
OVER THE WEEKEND...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH
TEMPERATURES REMAINING NEAR OR AROUND NORMAL.
LONG TERM (SUNDAY NIGHT-THURSDAY)...
MODELS CONTINUE TO INDICATE UPPER HEIGHTS FALLING AHEAD OF A
SHORTWAVE TROUGH PROGGED TO TRANSLATE EAST THEN NORTHEAST ACROSS THE
REGION WELL NORTHWEST OF OUR LOCAL AREA SUNDAY THROUGH TUESDAY. THIS
SHORTWAVE COMBINED WITH ANOTHER POTENT PIECE OF ENERGY DIVING
SOUTHEAST OVER THE PLAIN STATES WILL QUICKLY AMPLIFY THE OVERALL
UPPER PATTERN ACROSS THE COUNTRY CHARACTERIZED WITH A DEEPENING
TROUGH OVER THE EASTERN STATES AND RIDGING OUT WEST. THE ATTENDANT
COLD FRONT ASSOCIATED WITH THE LEAD SHORTWAVE IS FORECAST TO SWEEP
EAST ACROSS THE REGION AND GENERALLY LAYOUT FROM EAST TO WEST AND
STALL JUST NORTH OF OUR LOCAL AREA SOMETIME AROUND THE MID-WEEK TIME
FRAME AS IT LOSES ITS UPPER SUPPORT. THE ECMWF AND GFS/GFS ENSEMBLE
MEAN SOLUTIONS APPEAR TO BE IN BETTER AGREEMENT WITH THIS BOUNDARY
SPATIALLY AND TEMPORALLY THROUGH THIS...WHEREAS...24 HRS AGO
INDICATED LARGER DIFFERENCES. IF THIS VERIFIES...EXPECT THE
LOW-LEVEL FLOW LOCALLY TO GRADUALLY VEER TO THE SOUTH AND SOUTHWEST
MONDAY THROUGH TUESDAY AS A WARM FRONT LIFTS NORTH OVER THE EASTERN
GULF AND FL. THE RESULTANT DEEP AND MOIST SOUTHWEST FLOW SHOULD
TRANSLATE TO HIGHER THAN NORMAL RAIN CHANCES...ESPECIALLY OVER THE
NORTH AND NORTHEASTERN SECTIONS OF THE FORECAST AREA FROM THE LAKE
TO PALM BEACH REGION. DUE TO THE BETTER AGREEMENT BETWEEN THE LATEST
MODEL GUIDANCE AND PERSISTENCE FROM RUN TO RUN...WILL SLIGHTLY
INCREASE THE RAINFALL PROBABILITIES MONDAY THROUGH THE MID-WEEK
PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS AND WILL PERSIST THROUGH THE
WEEKEND WITH SCATTERED SHOWERS AND STORMS POSSIBLE...ESPECIALLY
OVERNIGHT AND THROUGH THE EARLY MORNING HOURS ACROSS THE ATLANTIC
WATERS. SEAS WILL GRADUALLY TREND DOWN THROUGH THE WEEKEND TO
AROUND NORMAL. WINDS ARE FORECAST TO SHIFT SOUTH AND POSSIBLY
SOUTHWEST SOMETIME NEXT WEEK FROM MONDAY THROUGH WEDNESDAY AS
ANOTHER FRONTAL BOUNDARY APPROACHES AND STALLS NORTH OF THE MARINE
AREA.
FIRE WEATHER...
MOIST CONDITIONS WILL KEEP RH`S WELL ABOVE CRITICAL LEVELS THROUGH
THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 77 86 76 / 30 20 30 20
FORT LAUDERDALE 86 78 88 78 / 20 20 30 20
MIAMI 87 78 88 78 / 30 20 40 20
NAPLES 89 74 91 75 / 30 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1128 AM EDT FRI SEP 14 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY ALONG WITH SOME SHOWERS.
FOLLOWING THE COLD FRONT...SEASONABLY COOLER AIR WILL OVERSPREAD THE
AREA FOR THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z SURFACE ANALYSIS SHOWS SLOW-MOVING COLD FRONT ORIENTED FROM
JUST WEST OF OTTAWA ONTARIO SOUTHWEST ACROSS CENTRAL LAKE ONTARIO
TO JUST WEST OF NIAGARA FALLS AND BUFFALO AND SOUTHWEST ACROSS
LAKE ERIE TO NEAR CLEVELAND. BOTH VISIBLE SATELLITE AND RADAR
IMAGERY SHOW ASSOCIATED CLOUDS AND SHOWERS JUST WEST OF THE
LEADING EDGE WHICH IS A CLASSIC ANAFRONTAL SIGNATURE. BROAD BAND
OF SHOWERS...ABOUT 100 MILES WIDE...ARE APPROXIMATELY 80 MILES
WEST OF BUFFALO.
ALOFT THE SHOWERS ARE FORCED BY A MID-LEVEL TROUGH SHIFTING ACROSS
THE GREAT LAKES AND A 65KT JET ROUNDING THE BASE OF THE TROUGH. AS
OF 15Z NO LIGHTING HAS BEEN OBSERVED BUT AS THE SYSTEM MOVES
CLOSER TO THE EASTERN LAKES SOME STRENGTHENING OF THIS JET ALONG
WITH MODEL INDICATED INSTABILITY INCREASING AHEAD OF THE MAIN AREA
OF SHOWERS COULD PRODUCE SOME ISOLATED LIGHTING. THIS IS
ESPECIALLY TRUE IF ANYTHING CONVECTIVE FORMS AHEAD OF THE MAIN
LINE LIKE RECENT HRRR RUNS HAVE HINTED AT. WILL SHIFT CONVECTIVE
CHANCES EAST ALONG THE LEADING EDGE CLOSER TO THE INSTABILITY AND
REMOVE FROM MAIN SHOWERS.
TIMING OF THE SHOWERS SHOULD KEEP MUCH OF THE AREA DRY THROUGH THE
EARLY AFTERNOON WITH SHOWERS ARRIVING 19-20Z ACROSS THE FAR
WEST...20-21Z OR SO ACROSS THE GENESEE VALLEY...21-22Z ACROSS THE
FINGER LAKES (OR EARLIER IF CONVECTION DEVELOPS)...AND 22Z/23Z
ACROSS THE NORTH COUNTRY. AT THIS POINT...ALL INDICATIONS POINT TO
THE STEADIEST PRECIP LASTING FOR ROUGHLY A 3-4 HOUR WINDOW...BEFORE
QUICKLY TAPERING OFF FROM WEST TO EAST BETWEEN LATE THIS AFTERNOON
AND THIS EVENING.
TONIGHT...THE ANAFRONTAL PRECIP WILL FINISH TAPERING OFF ACROSS OUR
EASTERN ZONES THIS EVENING...WHILE A NORTHWESTERLY FLOW OF MUCH
COOLER AIR OVERSPREADS THE AREA BEHIND THE DEPARTING FRONT...WITH
850 MB TEMPS FALLING TO +4C TO +6C BY LATE TONIGHT. WITH SOME
LINGERING SYNOPTIC-SCALE MOISTURE STILL IN PLACE BEHIND THE
FRONT...THIS SHOULD BE ENOUGH TO EVENTUALLY TRIGGER A LIMITED LAKE
RESPONSE SOUTHEAST OF LAKE ONTARIO...WHERE SOME SCATTERED LAKE
EFFECT RAIN SHOWERS WILL DEVELOP DURING THE OVERNIGHT HOURS.
IN TERMS OF TEMPERATURES...READINGS TODAY WILL EXHIBIT A WEST TO
EAST GRADIENT GIVEN THE APPROACH AND PASSAGE OF THE FRONT...WHILE
ALSO TENDING TO MAX OUT IMMEDIATELY PRIOR TO ITS PASSAGE AND THE
ONSET OF THE MAIN BAND OF SHOWERS...AFTER WHICH TIME TEMPS SHOULD
STEADILY COOL. EXPECT HIGHS TO RANGE FROM THE LOWER TO MID 70S
ACROSS THE FAR WEST...TO THE LOWER 80S ACROSS EASTERN SECTIONS WHERE
THE FRONT WILL ARRIVE LAST AND WHERE THERE WILL MORE IN THE WAY OF
SUNSHINE TO HELP MIX DOWN THE +13/+14C TEMPS AT 850 MB. AFTER
THAT...MUCH COOLER AIR WILL OVERSPREAD THE REGION AND RESULT IN
OVERNIGHT LOWS RETURNING TO MUCH MORE SEASONABLE LEVELS IN THE UPPER
40S AND LOWER 50S TONIGHT.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
A LOW AMPLITUDE FLOW OVER THE NORTH ATLANTIC WILL KEEP A PROGRESSIVE
PATTERN IN PLACE ACROSS OUR REGION THROUGH MUCH OF NEXT WEEK...AND
FOR THIS PARTICULAR PERIOD...THAT WILL INCLUDE AN EXPANSIVE SFC HIGH
THAT WILL KEEP THE WEEKEND LARGELY DRY AND COMFORTABLE. WHILE WE
WILL START OFF SEASONABLY COOL...TEMPERATURES HEADING INTO EARLY
NEXT WEEK WILL TREND HIGHER. THE DETAILS...
THIS PERIOD WILL OPEN WITH SOME NUISANCE LAKE EFFECT RAIN SHOWERS
SOUTHEAST OF LAKE ONTARIO AS A CHILLY NORTHWEST FLOW OF 4C H85 AIR
WILL BE FOUND OVER THE LOWER LAKES. AT THIS POINT YESTERDAY...
GUIDANCE WAS SUGGESTING THAT THE AIRMASS MIGHT BE TOO DRY FOR MUCH
LAKE RESPONSE. THAT HAS SINCE CHANGED WITH BOTH THE NAM AND RGEM
LEANING TOWARDS A FAIRLY MOIST ENVIRONMENT BELOW 8K FT WHERE A WEAK
INVERSION WILL BE IN PLACE. A WELL ALIGNED 300 FLOW MAY EVEN ALLOW
FOR A CONNECTION TO GEORGIAN BAY...WHICH WOULD FAVOR A WELL DEFINED
EARLY SEASON BAND FROM ABOUT WAYNE COUNTY SOUTHEASTWARD WITH MORE
SCATTERED SHOWERS WITHIN 25 MILES EITHER SIDE OF THE AXIS. IF THE
MULTI-LAKE CONNECTION DOES DEVELOP...ANY SINGLE BAND WOULD QUICKLY
BREAK DOWN AND BECOME MULTI-CELLULAR BY MID MORNING.
AS SATURDAY WEARS ON...LARGE SCALE SUBSIDENCE ASSOCIATED WITH AN
APPROACHING SFC HIGH OVER LOWER MICHIGAN WILL COMBINE WITH STRONG
DIURNAL MIXING TO BREAK DOWN/END THE LAKE DRIVEN ACTIVITY. THIS
PROCESS WOULD ALSO PROMOTE SOME SUNSHINE ELSEWHERE ACROSS OUR
FORECAST AREA WITH THE LAKE EFFECT RAIN SHOWERS ENDING BY MID
AFTERNOON. AS ONE WOULD EXPECT WITH H85 TEMPS AROUND 4C...IT WILL BE
COOL ON SATURDAY WITH HIGHS ONLY IN THE 60S.
THE SFC HIGH WILL DRIFT ACROSS LAKE ERIE SATURDAY NIGHT...WITH
MAINLY CLEAR SKIES AND LIGHT WINDS SUPPORTING VERY GOOD RADIATIONAL
COOLING. OVERNIGHT LOWS WILL RANGE FROM THE MID AND UPPER 30S ACROSS
THE NORTH COUNTRY AND SRN TIER VALLEYS TO THE MID 40S ALONG THE
IMMEDIATE LAKE SHORES. WHILE THIS WILL ALSO MEAN A FAIR AMOUNT OF
VALLEY FOG ACROSS THE SRN TIER...WE WILL ALSO HAVE THE LIKELIHOOD
FOR THE FIRST FROST OF THE SEASON. IT IS STILL TOO EARLY TO ISSUE
ANY FROST RELATED PRODUCTS BUT WATCH FOR POSSIBLE ADVISORIES AS THE
EVENT DRAWS CLOSER.
ON SUNDAY...THE DOMINANT HIGH PRESSURE SYSTEM WILL DRIFT SOUTHEAST
TO THE MID ATLANTIC STATES WHILE OUR AIRMASS MODIFIES TO MORE
COMFORTABLE LEVELS. AMPLE SUNSHINE COUPLED WITH H85 TEMPS ELEVATING
TO 8C WILL FAVOR AFTERNOON HIGHS WITHIN A FEW DEGREES OF 70. ALL IN
ALL...THIS SHOULD BE A BEAUTIFUL DAY FOR GETTING OUT AND ENJOYING
THE OUTDOORS.
OUR NEXT COLD FRONT WILL SLOWLY SETTLE ACROSS THE UPPER GREAT LAKES
SUNDAY NIGHT WHILE OUR CONTROLLING SFC HIGH WILL MOVE OFF THE EAST
COAST. THE STRENGTHENING SOUTHERLY FLOW BETWEEN THE SYSTEMS WILL
HELP TO HOLD OUR TEMPERATURES AT LEAST 5 DEGREES F HIGHER THAN THE
PREVIOUS CHILLY NIGHT...SO THAT SUNDAY NIGHT LOWS WILL RANGE FROM
THE 40S EAST OF LK ONTARIO AND IN THE SRN TIER VALLEYS TO THE LOWER
50S MOST ELSEWHERE.
THE AFOREMENTIONED COLD FRONT WILL ONLY MAKE IT AS FAR SOUTHEAST AS
LOWER MICHIGAN ON MONDAY AS A SIGNIFICANT WAVE RIDING UP ALONG THE
FRONT WILL IMPEDE ITS PROGRESS. THIS WILL BENEFIT OUR REGION IN THAT
MONDAY WILL FEATURE CONTINUED WARMING WITH AFTERNOON TEMPERATURES
TOPPING OUT IN THE MID TO UPPER 70S. IN TERMS OF SUNSHINE... SUNNY
SKIES EARLY WILL PROBABLY FADE BEHIND INCREASING HIGH CLOUDINESS...
BUT IT WILL STILL BE A NICE DAY BY ANYONES STANDARDS.
MOISTURE BEING DRAWN NORTHWARDS AHEAD OF THE SLOW MOVING FRONT
MONDAY NIGHT COULD LEAD TO SOME SHOWERS OVERNIGHT WITH TEMPERATURES
BEING HELD WELL ABOVE NORMAL.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A HIGH AMPLITUDE FLOW WILL BE IN PLACE ACROSS NORTH AMERICA DURING
THIS PERIOD...WITH AN ANOMALOUSLY DEEP TROUGH BEING CENTERED OVER
THE UPPER GREAT LAKES. THIS WILL INITIALLY RESULT IN SOME VERY
UNSETTLED WEATHER ACROSS OUR REGION WHICH WILL THEN BE FOLLOWED BY
SEASONABLY COOL CONDITIONS.
BREAKING THIS DOWN ON A DAY BY DAY BASIS...
A STRONG SHORTWAVE WILL DIVE INTO AN ALREADY DEEP LONGWAVE TROUGH
OVER THE UPPER GREAT LAKES ON TUESDAY WHILE A 1000MB SFC LOW WILL
LIFT ACROSS NEW YORK STATE. THIS WILL LIKELY PRODUCE A RAINY DAY
ACROSS OUR REGION WITH MANY AREAS PICKING UP A HALF TO ONE INCH OF
RAINFALL. FROM THIS DISTANT VANTAGE POINT...GUIDANCE IS SUGGESTING
THAT A 120KT H25 JET OVER SRN ONTARIO WILL PRODUCE THE STRONGEST JET
ENHANCED LIFT OVER THE FINGER LAKES AND EASTERN LAKE ONTARIO REGION
SO THAT IS WHERE THE HEAVIER RAIN WILL BE MOST FAVORABLE.
AS THE VIGOROUS SHORTWAVE ROUNDS THE BASE OF THE H5 TROUGH TUESDAY
NIGHT...THE SFC LOW WILL LIFT AWAY ACROSS QUEBEC. THE ISENTROPIC
LIFT WILL EXIT TO THE NORTHEAST IN THE PROCESS...BUT DEEP SYNOPTIC
MOISTURE WILL WRAP BACK ACROSS OUR FORECAST AREA WHILE THE H5 TROUGH
WILL BECOME NEGATIVELY TILTED AND LIFT OVER THE LOWER GREAT LAKES.
THIS SHOULD KEEP AT LEAST SCATTERED SHOWERS OVER OUR REGION...
ALTHOUGH STRONG COLD ADVECTION ON THE BACKSIDE OF THE SFC LOW WILL
PROMOTE LAKE ENHANCEMENT TO THE ONGOING SYNOPTIC SHOWERS.
ON WEDNESDAY...THE BASE OF THE H5 TROUGH WILL LIFT AWAY ACROSS
QUEBEC WHILE A FLAT SHORTWAVE RIDGE WILL QUICKLY FOLLOW IN ITS WAKE.
THE ASSOCIATED SFC HIGH SHOULD KEEP THE BULK OF THE FORECAST AREA
RAIN FREE...BUT LAKE INDUCED INSTABILITY WILL KEEP THE POTENTIAL FOR
SHOWERS INTACT FOR SITES EAST OF ROC AND IN PARTICULAR...EAST OF LK
ONTARIO. MEANWHILE...H85 TEMPS AROUND +3C WILL TRANSLATE INTO A VERY
COOL DAY AS AFTERNOON TEMPS WILL GENERALLY BE IN THE MID 60S. THE
COOLEST CONDITIONS WILL BE IN THE SRN TIER WHERE SOME SPOTS WILL NOT
RECOVER OUT OF THE 50S.
FOR THURSDAY...A FULL LATITUDE BUT BROADER BASED H5 TROUGH WILL BE
CENTERED OVER THE UPPER GREAT LAKES AS A DEEP CYCLONIC FLOW WILL BE
FOUND OVER WESTERN AND NORTH CENTRAL NEW YORK. WHILE AN APPROACHING
FRONTAL SYSTEM COULD TOUCH OFF SOME SHOWERS OVER THE FAR WESTERN
COUNTIES...THE BULK OF THE DAY LOOKS TO BE RAIN FREE AT THIS POINT.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
DURING THE COURSE OF TODAY...A COLD FRONT WILL SLOWLY CROSS THE
REGION FROM WEST TO EAST...WITH A 3-4 PERIOD OF SHOWERS AND
ASSOCIATED MVFR CONDITIONS FOLLOWING ITS PASSAGE. FORECAST TIMING OF
THIS HAS SLOWED DOWN A BIT FROM 12Z THINKING SO ADJUSTED TAFS
ACCORDINGLY. THIS PERIOD OF SHOWERS SHOULD BEGIN ACROSS THE FAR
WESTERN TAF SITES AROUND 19-20Z...KROC AROUND 20-21Z...AND KART
AROUND 22-23Z. A FEW EMBEDDED THUNDERSTORMS ARE POSSIBLE OUT
AHEAD OF THE MAIN AREA OF SHOWERS CLOSER TO INSTABILITY DEVELOPING
OUT AHEAD OF THE FRONT. THE PROBABILITY OF THESE APPEARS TOO LOW TO
MENTION GIVEN ONLY LIMITED AMOUNTS OF INSTABILITY.
FOLLOWING THE END OF THE FRONTAL PRECIP...THE COMBINATION OF
LINGERING LOW LEVEL MOISTURE AND LAKE INFLUENCES WILL KEEP A MIX
OF MVFR TO LOW VFR CIGS IN PLACE TONIGHT...WITH THE LOWEST CIGS
FOUND DOWNWIND /EAST-SOUTHEAST/ OF LAKES ERIE AND ONTARIO. WITH
INCREASING AMOUNTS OF LAKE-DRIVEN INSTABILITY...SOME SCATTERED
RAIN SHOWERS WILL ALSO BECOME POSSIBLE SOUTHEAST OF LAKE ONTARIO.
OUTLOOK...
SATURDAY...MVFR/VFR IN THE MORNING WITH SCATTERED SHOWERS
SOUTHEAST OF LAKE ONTARIO...THEN IMPROVING TO VFR.
SUNDAY AND MONDAY...VFR.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/ASSOCIATED MVFR.
&&
.MARINE...
A COLD FRONT WILL CROSS THE LOWER GREAT LAKES TODAY...WITH A PERIOD
OF SHOWERS AND POSSIBLE EMBEDDED THUNDERSTORMS IMMEDIATELY FOLLOWING
THE FRONTAL PASSAGE. MORE IMPORTANTLY...WINDS WILL ALSO VEER TO
NORTHWESTERLY AND FRESHEN BEHIND THE FRONT...BRINGING A PERIOD OF
ADVISORY-LEVEL CONDITIONS TO LAKE ONTARIO THIS AFTERNOON AND
TONIGHT. ON LAKE ERIE...WINDS AND WAVES WILL NOT STRENGTHEN QUITE AS
MUCH...WITH CONDITIONS REMAINING A LITTLE BELOW ADVISORY LEVELS.
AFTER THAT...HIGH PRESSURE WILL BUILD ACROSS THE LOWER LAKES THIS
WEEKEND...BRINGING DIMINISHING WINDS AND WAVES.
&&
.CLIMATE...
ALL THREE OF OUR CLIMATE SITES REACHED AT LEAST 80F THURSDAY. THIS
SAID...ALL THREE LOCATIONS CONTINUE TO RANK THIRD FOR GREATEST
NUMBER OF 80F DAYS IN A YEAR.
BUFFALO (SINCE 1944)
1 83 1949
2 82 1959
3 79 2012
AVG: 54 DAYS
ROCHESTER (SINCE 1871)
1 91 1959
2 86 2007
3 85 2012
AVG: 59 DAYS
WATERTOWN (SINCE 1949)
1 75 1949
2 73 1959
3 72 2012
AVG: 45 DAYS
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EDT
SATURDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
LOZ042.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT
SATURDAY FOR LOZ045.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR/SMITH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...JJR/SMITH
MARINE...JJR/SMITH
CLIMATE...THOMAS/JJR
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
936 AM EDT FRI SEP 14 2012
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM THE NORTHEAST TODAY
WITH ONSHORE FLOW PRODUCING SCATTERED SHOWERS FROM OFFSHORE. A WEAK
COLD FRONT WILL MOVE THROUGH THE AREA FROM THE NORTHWEST LATE
TONIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD IN SATURDAY NIGHT AND
EXTEND OVER THE AREA THROUGH SUNDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH FROM THE WEST TUESDAY AND MOVE THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM FRIDAY...EASTERN NORTH CAROLINA CURRENT SITS IN A
SHEAR AXIS BETWEEN UPPER LOW OFFSHORE AND DEEPENING MID-LEVEL
TROUGH OUT NEAR THE MOUNTAINS. WITH DEEP ONSHORE FLOW AND A MUCH
MORE MOIST ENVIRONMENT THAT PREVIOUS DAYS...SHOWERS HAVE BLOSSOMED
NEAR THE COAST AND HAVE MOVED INLAND FROM THE PAMLICO SOUND NORTH.
EXPECT ADDITIONAL SHOWERS TO AFFECT THE SOUTHERN COUNTIES AND WILL
CONTINUE WITH CHANCE POPS THROUGH MOST OF THE DAY PER LATEST NAM12
WHICH SEEMS TO HAVE A BETTER HANDLE ON THE CURRENT SITUATION THAT
THE RAP OR GFS. NO OTHER MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM / SATURDAY THROUGH 6 AM SATURDAY/...
AS OF 330 AM FRIDAY...SHRT WV TROF MOVING ACROSS N OF AREA WILL
RESULT IN WEAK SFC COLD FRONT MOVING IN FROM NW OVERNIGHT...BREAKING
DOWN PERSISTENT NE-SW ORIENTED SFC RIDGE. NO SIGNIFICANT WX
ACCOMPANYING FRONT BUT SHRT WV AND LINGERING CONVERGENCE WILL KEEP
THREAT OF ISOLD SHOWERS OVER SRN COASTAL SECTIONS DURING
EVENING...THUS ADDED 20 POPS THERE. MOS BLEND SUPPORTS PREVIOUS FCST
MIN TEMPS...LOWER 60S INLAND TO LOWER 70S COAST.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 400 AM FRI...MODEL GUIDANCE REMAINS IN FAIRLY CLOSE AGREEMENT
ON MAJOR SYNOPTIC FEATURES THROUGH THE LONG TERM PERIOD. THROUGH 84
HOURS GENERALLY FOLLOWED A BLEND OF NAM/GFS/SREF...THEN
TRANSITIONING TO A BLEND OF 00Z GFS AND 12Z ECMWF. LOOKING AT LATEST
00Z ECMWF IT REMAINS VERY SIMILAR TO THE 00Z GFS. DID NOT MAKE ANY
SIGNIFICANT CHANGES TO THE FORECAST THIS PERIOD. BASED ON GFS AND
NAM GUIDANCE DID INTRODUCE A SLIGHT CHANCE OF POPS SATURDAY
AFTERNOON AND EVENING ASSOCIATED WITH A WEAK BOUNDARY PASSING THROUGH
THE AREA. A SURFACE RIDGE WILL PASS TO THE NORTH SUNDAY...THEN OFF
THE MID ATLANTIC COAST MONDAY. SOUTHERLY FLOW WILL SET UP MONDAY
AHEAD OF THE NEXT COLD FRONT APPROACHING THE AREA. POPS WILL BEGIN
INCREASING ON MONDAY...REACHING AROUND 50 PERCENT BY
TUESDAY...GRADUALLY DIMINISHING AS THE COLD FRONT MOVES THROUGH ON
WEDNESDAY. IF FRONT PUSHES COMPLETELY THROUGH WEDNESDAY IT SHOULD BE
DRY WITH CLEARING. FORECAST CONTINUED TO CARRY SMALL POPS AND SOME
CLOUDS ALLOWING FOR POSSIBILITY OF FRONT SLOWING AND HANGING ALONG
THE COAST A BIT. EXPECT DRY CONDITIONS FOR THURSDAY WITH HIGH
PRESSURE BUILDING IN BEHIND THE FRONT.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH 12Z SATURDAY/...
AS OF 700 AM FRIDAY...VFR EXPECTED TO PREVAIL INTO EVENING...THEN
GDNC INDICATING SUB-VFR CONDITIONS OVERNIGHT. SCT- BKN SCU/AC HAS
PRECLUDED FOG/STRATUS DEVELOPMENT THIS MORNING...WITH SCT SHOWERS
CONTINUING TO PUSH IN ALONG COAST WITH ONSHORE FLOW. SHOWERS WILL
APPROACH TAF SITES DURING THE DAY AND WILL COVER WITH VCSH IN
TAFS. GDNC INDICATES PERIOD OF IFR CIGS/VSBYS ALL SITES LATE
TONIGHT...BUT HAS BEEN OVERDONE PAST FEW NIGHTS AND NOT ENOUGH
CONFIDENCE TO GO BELOW MVFR AT THIS TIME.
LONG TERM /TONIGHT THROUGH TUESDAY/...
AS OF 400 AM FRI...PREDOMINANT VFR/DRY CONDITIONS EXPECTED THROUGH
THE WEEKEND EXCEPT FOR AN ISOLATED SHOWER/TSTM SATURDAY
AFTERNOON/EVENING SOUTHERN AREAS. SEVERAL SURFACE FEATURES WILL
BRING A CHANCE FOR SCATTERED CONVECTION MONDAY INTO WEDNESDAY...WITH
THE BEST CHANCE TUESDAY INTO TUESDAY NIGHT. PRECIP WILL BE MOSTLY
JUST SHOWERS THOUGH CAN`T RULE OUT THUNDER AT TIMES. MOST OF THE
ACTIVITY WILL BRING MVFR CONDITIONS...HOWEVER CANNOT RULE OUT SOME
PERIODS OF IFR ESPECIALLY TUESDAY INTO TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 935 AM FRIDAY...BASED ON CURRENT OBSERVATIONS HAVE TWEAKED
WIND DIRECTIONS TO MORE NE WITH SPEEDS AT 10 TO 15 KNOTS PER
LATEST BUOY OBSERVATIONS. SEAS CONTINUE IN THE 2 TO 4 FOOT RANGE
WITH A GENERAL 6 TO 7 SECOND SWELL COMPONENT. THESE CONDITIONS
SHOULD PREVAIL THROUGH THE AFTERNOON.
LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 400 AM FRI...MAINLY LIGHT TO MODERATE NORTH TO NORTHEAST WINDS
FOR SATURDAY WILL DIMINISH AND BECOME MORE EASTERLY BY LATE SUNDAY.
AS A SURFACE RIDGE PASSES BY TO THE NORTH. SEAS WILL INCREASE TO
SMALL CRAFT HOWEVER BEGINNING SATURDAY EVENING...DUE TO SWELLS FROM
TROPICAL CYCLONE NADINE. THESE SWELLS WILL DIMINISH BY SUNDAY
EVENING...BUT WILL RESULT IN AN HIGH THREAT OF RIP CURRENTS THROUGH
THE WEEKEND. THE HIGH WILL MOVE EAST OF THE MID ATLANTIC COAST
MONDAY...WITH THE RESULTING FLOW VEERING TO SOUTH AND CONTINUING
INTO TUESDAY. THE SOUTHERLY FLOW WILL INCREASE MONDAY NIGHT AND
TUESDAY WITH SEAS BUILDING AGAIN TO SMALL CRAFT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR NCZ095-
103-104.
MARINE...NONE.
&&
$$
SYNOPSIS...RSB
NEAR TERM...CTC
SHORT TERM...RSB
LONG TERM...RSB
AVIATION...RSB/JBM
MARINE...RSB/CTC
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1037 AM EDT FRI SEP 14 2012
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE REGION TODAY. HIGH
PRESSURE WILL BUILD SOUTH INTO THE LOWER GREAT LAKES AND OHIO
VALLEY TONIGHT. THE HIGH WILL REMAIN ACROSS THE AREA THROUGH THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PCPN IS CONTINUING TO PROGRESS EAST ACROSS NORTHWEST PORTIONS OF
OUR FA. THERE DOES APPEAR TO BE SOME WEAKENING OF THE PCPN IN THE
PAST FEW RADAR IMAGES...BUT THE LATEST HRRR IS SILL TRYING TO PUSH
PCPN ACROSS OUR ENTIRE FA. WILL NOT GO QUITE AS AGGRESSIVE AS THE
HRRR WOULD SUGGEST BUT WILL STILL BUMP UP POPS A BIT MORE ACROSS
THE NORTH. SOME UNCERTAINTY EXISTS AS TO HOW MUCH CLEARING WILL
MAKE IT INTO OUR NORTHWEST LATER THIS AFTERNOON. HOWEVER...WITH
CLOUDS THROUGH AT LEAST A GOOD PORTION OF THE AFTERNOON AND
A DEVELOPING CAA PATTERN...WILL DROP HIGHS DOWN INTO THE MID TO
UPPER 60S THERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE WILL BUILD SOUTH INTO THE GREAT LAKES AND
OHIO VALLEY TONIGHT. SKIES WILL CLEAR FROM THE NORTH AS
DRIER...COOLER AIR SETTLES INTO THE REGION. RADIATIONAL COOLING
WILL BE IN FULL FORCE AND EXPECT OVERNIGHT LOWS TO RANGE FROM THE
LOWER 40S NW...AND IN SOME OF THE COLDER SPOTS OF CENTRAL OHIO...TO
THE LOWER 50S SOUTH.
UNDER A WNW FLOW PATTERN ALOFT...SURFACE HIGH PRESSURE WILL
REMAIN OVER THE REGION THROUGH SUNDAY. A FEW CUMULUS CLOUDS MIXED
WITH CIRRUS CAN BE EXPECTED DURING THE DAYTIME WITH MAINLY CLEAR
SKIES AT NIGHT. HIGHS WILL RANGE FROM THE LOWER TO MID 70S ON
SATURDAY...MODERATING SLIGHTLY INTO THE MID AND UPPER 70S ON SUNDAY.
RADIATIONAL COOLING WILL OCCUR ONCE AGAIN SATURDAY NIGHT WITH LOWS
RANGING FROM THE LOWER 40S TO THE LOWER 50S.
MODELS ARE COMING INTO BETTER AGREEMENT IN TERMS OF THE NEXT
WEATHER SYSTEMS TO AFFECT THE REGION INTO THE FIRST PART OF THE
WEEK. HAVE TAKEN A BLEND OF THE ECMWF AND THE GFS WHICH INDICATE
THAT A LONG WAVE TROUGH WILL DIG SOUTH INTO THE GREAT LAKES AND
OHIO VALLEY. MEANWHILE...UPR LVL ENERGY NEAR THE DESERT SW WILL
EJECT NE INTO TOWARD THE TN AND OHIO VALLEYS. IT IS STILL UNCLEAR
ON HOW MUCH MOISTURE WILL BE PULLED NORTHWARD INTO THE REGION FROM
THIS SYSTEM AS THE LONG WAVE TROUGH DIGS SOUTHEAST. HAVE RAISED
POPS FOR ALL LOCATIONS FOR MONDAY INTO MONDAY NIGHT...BUT THIS
VERY WELL COULD GO LIKELY...ESPECIALLY FOR THE SE HALF OF THE
AREA. GIVEN CLOUDS AND CHANCES FOR PCPN...HAVE LOWER HIGHS ON
TUESDAY INTO THE LOWER AND MID 70S.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS THE LONG WAVE TROUGH DIGS SOUTHEAST INTO THE REGION ON
TUESDAY...A COLD FRONT WILL PUSH SOUTHEAST THROUGH THE AREA. THIS
FRONT WILL PROVIDE FOR ANOTHER FOCUS OF SHOWERS. THE FRONT WILL
PUSH EAST OF THE REGION TUESDAY NIGHT INTO WEDNESDAY...ALLOWING
HIGH PRESSURE OF CANADIAN ORIGIN TO SET UP OVER THE OHIO VALLEY ON
WEDNESDAY. DAYTIME HIGHS WILL COOL INTO THE 60S BY WEDNESDAY...WHICH
WILL BE SOME 10 TO 15 DEGREES BELOW NORMAL FOR MID SEPTEMBER.
HIGH PRESSURE WILL THEN MOVE EAST OF THE AREA ON THURSDAY AS A
WEAK UPPER LEVEL DISTURBANCE PUSHES ACROSS THE GREAT LAKES.
HAVE GONE WITH A SLIGHT CHANCE OF SHOWERS WITH THIS SYSTEM.
TEMPERATURES WILL MODERATE INTO THE LOWER AND MID 70S.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
PRIMARY CONCERN FOR THE TAFS IS THE COLD FRONTAL PASSAGE EXPECTED
TO OCCUR THIS MORNING...WITH POTENTIAL FOR PRECIPITATION AND LOW
CEILINGS INTO THE AFTERNOON.
THE FRONT WILL BE MOVING SOUTHEAST THROUGH THE TAF SITES THIS
MORNING...WITH WINDS SHIFTING TO NNW AND EVENTUALLY BECOMING
SLIGHTLY GUSTY (UP TO 20 KNOTS). ALONG WITH THE WIND
SHIFT...MOISTURE WILL BE INCREASING NEAR AND BEHIND THE FRONT.
THIS SET OF TAFS IS SLIGHTLY MORE PESSIMISTIC THAN THE LAST
SET...WITH MVFR CEILINGS NOW APPEARING LIKELY FOR THE NORTHERN TAF
SITES. THERE ARE SOME IFR CEILINGS THAT HAVE DEVELOPED OVER
INDIANA...WHICH COULD POSSIBLY MOVE INTO KDAY THIS MORNING.
HOWEVER...MULTIPLE MODEL SOURCES ARE INDICATING THAT THESE VERY
LOW CEILINGS WILL LIFT SLIGHTLY BEFORE THE MOISTURE MAKES IT INTO
THE REGION.
PRECIPITATION IS NOT GOING TO BE A MAJOR CONCERN...AS
THERE IS NOT MUCH MOISTURE FOR THE FRONT TO WORK WITH. VCSH WILL
BEST HANDLE THE THREAT AT THIS TIME...WITH THE PRECIPITATION NOT
EXPECTED TO HIT EVERY LOCATION...AND NOT EXPECTED TO BE A
SIGNIFICANT CONCERN WITH REGARDS TO FLIGHT CATEGORIES. A TEMPO FOR
LIGHT SHOWERS HAS BEEN INCLUDED AT KDAY...WHERE PASSING SHOWERS
WILL BE MORE LIKELY.
NORTHERLY WINDS WILL BECOME LIGHT TONIGHT...WITH CLEARING SKIES
AND GENERALLY VFR CONDITIONS. THE SIGNIFICANT COOLING COULD LEAD
TO FOG IN VALLEY LOCATIONS (SUCH AS KLUK).
.OUTLOOK...MVFR CEILINGS ARE POSSIBLE ON MONDAY NIGHT AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...JGL
SHORT TERM...HICKMAN
LONG TERM...NOVAK
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS MIAMI FL
158 PM EDT FRI SEP 14 2012
.AVIATION...
SO FAR CONVECTION HAS NOT BECOME ESTABLISHED ACROSS THE SOUTH
FLORIDA PENINSULA. WITH MODERATE EASTERLY FLOW ACROSS THE REGION
CONVECTION IS EXPECTED TO BE MORE INLAND AND IN THE WESTERN PART
OF THE PENINSULA, WITH EAST COAST TAF SITES ASSIGNED VCSH AT 18Z
AND VCTS ASSIGNED TERMINAL KAPF AT 19Z WITH CONVECTION MAYBE
STARTING LATER AROUND 19-20Z. WITH A PASSING SHOWER AT EAST COAST
TERMINALS BRIEF SUB-VFR CONDITIONS POSSIBLE. IF THUNDERSTORMS DO
DEVELOP IN VICINITY OF TERMINAL KAPF BRIEF PERIODS OF IFR
CONDITIONS MAY BE POSSIBLE.
60
&&
.PREV DISCUSSION... /ISSUED 1017 AM EDT FRI SEP 14 2012/
UPDATE...
WEAKER EASTERLY FLOW IS OCCURRING ACROSS THE REGION THIS
MORNING...AS THE SURFACE BOUNDARY HAS DRIFTED A LITTLE SOUTH IN
THE FLORIDA STRAITS AND SURFACE HIGH PRESSURE HAS WEAKENED DUE TO
A SHORTWAVE TROUGH MOVING ACROSS THE GREAT LAKES. ISOLATED TO
WIDELY SCATTERED SHOWERS HAVE DEVELOPED OVER THE ATLANTIC...MAINLY
EAST OF PALM BEACH COUNTY. THE 12Z SOUNDING SHOWED A THIN DRY
LAYER BETWEEN 700 AND 750MB...WITH STEEPER LAPSE RATES ABOVE THIS
INVERSION. SO THE MODIFIED SOUNDING SHOWS THERE IS A LITTLE MORE
POTENTIAL FOR WIND TODAY...BUT STILL ONLY THE TYPICAL 40-50 MPH IN
THE STRONGEST STORMS...AND THIS WILL MAINLY BE FOR THE INTERIOR
AND THE GULF COAST. WITH THE LIGHTER FLOW...ISOLATED TO LOW END
SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE FOR THE
EAST COAST AREAS THROUGH MID AFTERNOON. AFTER THAT TIME...A GULF
COAST SEA BREEZE SHOULD DEVELOP...WITH THE BULK OF THE ACTIVITY
FOCUSING IN THIS REGION. NO MAJOR UPDATES WERE NEEDED TO THE GOING
FORECAST.
PREV DISCUSSION... /ISSUED 744 AM EDT FRI SEP 14 2012/
AVIATION...
THE RIDGE OF HIGH PRESSURE EXTENDING SOUTHWEST INTO THE
SE U.S. BEGINS TO WEAKEN AND MOVE NORTHEAST AS A LOW PRESSURE SYSTEM
AND THE ASSOCIATED COLD FRONT MOVE TOWARD THE EAST U.S. COAST TODAY
INTO SATURDAY. WITH THE PRESSURE GRADIENT OVER SOUTH FLORIDA
WEAKENING...THE EASTERLY WIND FLOW WILL PERSIST TODAY INTO SATURDAY
BUT MUCH LOWER. CURRENTLY WIDELY SCATTERED SHRA MOVING WEST FROM THE
ATLC ONSHORE WITH VERY BRIEF MVFR CIG/VSBY AT ANY E COAST TERMINAL
BUT ONLY VCSH IN TAFS AT THIS TIME. AFT 15Z...ISOLD TSRA POSSIBLE
BUT SHOULD BE WEST OF TERMINALS SO NO VCTS IN TAFS. WINDS VARIABLE
TO ENE < 10 KNOTS BECOMING AFT 14Z 10-13 KNOTS WITH GUSTS TO THE
MID/UPPER TEENS. AT KAPF...VFR THROUGH PERIOD WITH VCSH AFT 18Z.
TSRA POSSIBLE BUT NOT IN TAF AT THIS TIME. SURFACE WIND CURRENTLY
NE < 10 KNOTS BECOMING 10 TO 12 KNOTS AFT 15Z.
PREV DISCUSSION... /ISSUED 200 AM EDT FRI SEP 14 2012/
SHORT TERM (TODAY-SUNDAY)...
THE LATEST NUMERICAL GUIDANCE REMAINS IN GOOD AGREEMENT OVER THE
WEEKEND AND GENERALLY INDICATES LIGHT TO MODERATE EASTERLY FLOW
CONTINUING JUST NORTH OF A WEAK TROUGH OR WHAT IS LEFT OF THE
FRONTAL BOUNDARY THAT MOVED THROUGH A FEW DAYS AGO AND HIGH PRESSURE
TO THE NORTH. ALTHOUGH THE RAINFALL COVERAGE TODAY IS EXPECTED TO BE
LESS THAN YESTERDAY...SCATTERED SHOWERS OVER THE ADJACENT ATLANTIC
WATERS SPREADING ASHORE ACROSS PORTIONS OF THE EAST COAST AREAS
EARLY THIS MORNING WILL REMAIN POSSIBLE ONCE AGAIN. THIS LINES UP
WELL WITH THE LATEST HRRR AND WRF MODEL REFLECTIVITIES TODAY. FOR
THE AFTERNOON...EXPECT THIS ACTIVITY TO SPREAD INLAND AND BECOME
CONCENTRATED OVER THE INTERIOR AND WESTERN AREAS THROUGH THE EVENING
HOURS BEFORE DIMINISHING. THE EASTERLY FLOW HAS WEAKENED COMPARED TO
YESTERDAY...WHICH SHOULD ALLOW A WEST COAST SEA BREEZE TO BECOME
ESTABLISHED THIS AFTERNOON. THE MAIN IMPACTS FROM THIS
AFTERNOON/EVENING ACTIVITY WILL BE THE POTENTIAL FOR PERIODS WITH
HEAVY RAIN AND GUSTY WINDS WITH ANY STRONGER STORMS THAT DEVELOP.
HOWEVER...MODEL SOUNDINGS ARE NOT THAT IMPRESSIVE AND INDICATE
MEAGER MID-LEVEL LAPSE RATES WITH NEAR AVERAGE 500 MB TEMPERATURES.
OVER THE WEEKEND...SIMILAR CONDITIONS WILL BE EXPECTED EACH DAY WITH
TEMPERATURES REMAINING NEAR OR AROUND NORMAL.
LONG TERM (SUNDAY NIGHT-THURSDAY)...
MODELS CONTINUE TO INDICATE UPPER HEIGHTS FALLING AHEAD OF A
SHORTWAVE TROUGH PROGGED TO TRANSLATE EAST THEN NORTHEAST ACROSS THE
REGION WELL NORTHWEST OF OUR LOCAL AREA SUNDAY THROUGH TUESDAY. THIS
SHORTWAVE COMBINED WITH ANOTHER POTENT PIECE OF ENERGY DIVING
SOUTHEAST OVER THE PLAIN STATES WILL QUICKLY AMPLIFY THE OVERALL
UPPER PATTERN ACROSS THE COUNTRY CHARACTERIZED WITH A DEEPENING
TROUGH OVER THE EASTERN STATES AND RIDGING OUT WEST. THE ATTENDANT
COLD FRONT ASSOCIATED WITH THE LEAD SHORTWAVE IS FORECAST TO SWEEP
EAST ACROSS THE REGION AND GENERALLY LAYOUT FROM EAST TO WEST AND
STALL JUST NORTH OF OUR LOCAL AREA SOMETIME AROUND THE MID-WEEK TIME
FRAME AS IT LOSES ITS UPPER SUPPORT. THE ECMWF AND GFS/GFS ENSEMBLE
MEAN SOLUTIONS APPEAR TO BE IN BETTER AGREEMENT WITH THIS BOUNDARY
SPATIALLY AND TEMPORALLY THROUGH THIS...WHEREAS...24 HRS AGO
INDICATED LARGER DIFFERENCES. IF THIS VERIFIES...EXPECT THE
LOW-LEVEL FLOW LOCALLY TO GRADUALLY VEER TO THE SOUTH AND SOUTHWEST
MONDAY THROUGH TUESDAY AS A WARM FRONT LIFTS NORTH OVER THE EASTERN
GULF AND FL. THE RESULTANT DEEP AND MOIST SOUTHWEST FLOW SHOULD
TRANSLATE TO HIGHER THAN NORMAL RAIN CHANCES...ESPECIALLY OVER THE
NORTH AND NORTHEASTERN SECTIONS OF THE FORECAST AREA FROM THE LAKE
TO PALM BEACH REGION. DUE TO THE BETTER AGREEMENT BETWEEN THE LATEST
MODEL GUIDANCE AND PERSISTENCE FROM RUN TO RUN...WILL SLIGHTLY
INCREASE THE RAINFALL PROBABILITIES MONDAY THROUGH THE MID-WEEK
PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS AND WILL PERSIST THROUGH THE
WEEKEND WITH SCATTERED SHOWERS AND STORMS POSSIBLE...ESPECIALLY
OVERNIGHT AND THROUGH THE EARLY MORNING HOURS ACROSS THE ATLANTIC
WATERS. SEAS WILL GRADUALLY TREND DOWN THROUGH THE WEEKEND TO
AROUND NORMAL. WINDS ARE FORECAST TO SHIFT SOUTH AND POSSIBLY
SOUTHWEST SOMETIME NEXT WEEK FROM MONDAY THROUGH WEDNESDAY AS
ANOTHER FRONTAL BOUNDARY APPROACHES AND STALLS NORTH OF THE MARINE
AREA.
FIRE WEATHER...
MOIST CONDITIONS WILL KEEP RH`S WELL ABOVE CRITICAL LEVELS THROUGH
THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 86 76 88 / 20 30 20 40
FORT LAUDERDALE 78 88 78 88 / 20 30 20 40
MIAMI 78 88 78 87 / 20 40 20 40
NAPLES 74 91 75 90 / 30 40 30 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
112 PM EDT FRI SEP 14 2012
.AVIATION...
HIGH PRESSURE AND DRY AIR WILL CONTINUE TO FILTER INTO THE AREA
BEHIND THE EXITING COLD FRONT. THIS WILL BRING VFR CONDITIONS
THROUGH THE PERIOD. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT AS
THE SURFACE HIGH SETTLES OVER THE REGION BUT FOG IS NOT EXPECTED
TO BE A CONCERN GIVEN THE VERY DRY LOW LEVELS.
&&
.PREV DISCUSSION... /ISSUED 413 AM EDT FRI SEP 14 2012/
SHORT TERM...
PRIMARY POST FNTL RAIN BAND IN ASSOCN/W POTENT UPR TROUGH OVR NE MN
TEMPORARILY IN THE PROCESS OF DECAY ACRS NW IN ATTM AS UPR SPEED MAX
PULLS AWAY. HWVR UPSTREAM SAT OBS AND MOST RECENT RADAR DATA SHOW
INTENSIFICATION/EXPANSION OF SECONDARY AREA OF RAINFALL ACRS CNTRL
IL TIED TO SECONDARY UPR SPEED MAX WHICH 06Z RUC MODEL GUIDANCE
LOOKS TO HAVE A GOOD HANDLE ON. 00Z GUIDANCE OUTSIDE GFS MUCH FASTER
W/EWD EXIT OF PCPN BUT BASED ON RUC/GFS AND FURTHER SPC 4KM WRF WILL
MAKE SOME SIG CHGS TO HOLD ONTO PCPN ACRS ERN IN FOR A BIT LONGER
THROUGH 15Z. OTHERWISE SIG FNTL SURGE XPCD LTR TDA AS NRN STREAM SW
OPENS FURTHER AND ACCELERATES INTO WRN QB BY LT AFTN. THUS CWA WILL
SEE RAPID W-E CLRG AND SIG COLUMN DRYING AS DEEP SUBSIDENCE SOUTH OF
MID LVL TROUGH SPREADS SEWD. DEEP MIXING AND INSOLATION WILL OFFSET
EARLY LL CAA WING W/PRIOR GRIDDED MAX TEMPS CLOSE AND HELD.
COOL CANADIAN SFC RIDGE FOLLOWS TONIGHT W/IDEAL RADIATIONAL COOLING
XPCD. DEGREE OF DRYING XPCD THROUGH THIS AFTN WILL CURTAIL ANY LT
NIGHT FOG THREAT W/MINS SETTLING INTO THE LOW-MID 40S.
SFC RIDGE REMAINS ENTRENCHED ACRS THE AREA THROUGH SUN W/NO SENSIBLE
WX CONCERNS. XPC SEASONABLE TEMPS W/SLIGHT WARMING TREND THROUGH THE
WEEKEND.
LONG TERM...
SUNDAY THROUGH THURSDAY...THE UPPER LEVEL PATTERN OVER NORTH AMERICA
WILL BECOME MORE AMPLIFIED THIS PERIOD AS SEVERAL SHORT WAVE TROFS
MOVE RAPIDLY SOUTHEAST TOWARD THE GREAT LAKES REGION. THE 500 MB
ANALOGS...GFS OPERATIONAL RUN AND THE BULK OF THE GFS ENSEMBLES ALL
IN REASONABLE AGREEMENT WITH ONE ANOTHER THAT A LONG WAVE TROF WILL
BECOME ESTABLISHED OVER EASTERN NORTH AMERICAN AND EXTEND ACROSS THE
WESTERN GREAT LAKES REGION. THERE WILL BE BRIEF WARMUPS AHEAD OF EACH
INDIVIDUAL TROF...SO TIMING OF THESE SMALLER SYSTEMS WITHIN THE MAIN
TROF OUT SEVERAL DAYS A LITTLE TRICKY AT THIS POINT. HOWEVER...THE
ONGOING TIMING OF THE FIRST 2 WAVES APPEARS ON TRACK IN REGARD TO
THE LATEST MODEL RUNS MENTIONED ABOVE. HAVE MADE JUST SOME MINOR
CHANGES...KEEPING A CHANCE FOR RAIN MONDAY NIGHT AND AGAIN THURSDAY.
HAVE REMOVED RAIN CHANCES WEDNESDAY NIGHT TO TRY TO BECOME MORE
REPRESENTATIVE WITH THE FORECAST. AS FOR TEMPERATURES...THE GFS/MEX
APPEARS ON TRACK SUNDAY AND MONDAY...BUT THE GFS MEAN ENSEMBLE MOS
APPEARS TOO COOL WITH HIGHS. HOWEVER...THE MEAN ENSEMBLE MOS DOES
APPEAR ON TRACK TUESDAY THROUGH THURSDAY WITH HIGHS ONLY IN THE 60S.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK THROUGH LATE TONIGHT FOR INZ003.
MI...RIP CURRENT RISK THROUGH LATE TONIGHT FOR MIZ077.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...AGD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
534 PM EDT FRI SEP 14 2012
.SYNOPSIS...
SHOWERS WILL COME TO AN END THIS EVENING AS A COLD FRONT PUSHES
EAST OF THE AREA. DRY AND COOL CONDITIONS WILL FOLLOW WITH HIGH
PRESSURE BUILDING OVER THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
21Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT
FOR THE LATEST COLD FRONT POSITION AS IT CROSSES OUR AREA.
RADAR, OBS, AND SAT IMAGERY INDICATE THAT A COLD FRONT HAS PUSHED
EAST OF THE PITTSBURGH METRO AND CURRENTLY EXTENDS ALONG A LINE FROM
DUBOIS TO WASHINGTON TO NEW MARTINSVILLE. SHOWERS HAVE BEEN
LIMITED ALONG THE FRONT, WITH THE MORE MOISTURE STARVED PRE-
FRONTAL ENVIRONMENT SOUTH OF PITTSBURGH LIMITING COVERAGE TO JUST
ISOLATED SHOWERS. NORTHWARD OF KPIT, SHOWERS ARE MORE NUMEROUS
WITH BETTER FORCING FROM 500MB POSITIVE VORTICITY ADVECTION AS A
VORT LOBE PASS FROM NE OHIO INTO WESTERN PA. A NOTICEABLE 5-10
DEGREE DECREASE IN TEMPERATURES ALONG WITH A SOUTHWEST TO
NORTHWEST WIND SHIFT WITH THE FRONTAL PASSAGE.
TONIGHT...RADAR TRENDS ALONG WITH THE HRRR SUPPORT THE FRONT
PUSHING EAST OF THE RIDGES BY 00Z WITH ANY LINGERING SHOWERS
COMING TO AN END BY 03Z. BEHIND THE FRONTAL BAND OF MOISTURE,
DRIER AIR IN THE 900-250MB LAYER WILL ADVECT INTO THE AREA AND
ALLOW FOR CLEARING SKIES ACROSS THE AREA BY DAWN. HIGH PRESSURE WILL
THEN BEGIN TO BUILD IN FROM THE WEST AND BECOME CENTERED ACROSS
IN/OH BY DAWN. DESPITE CLEARING SKIES, LOOSENING PRESSURE GRADIENT
WILL STILL BE ENOUGH FOR 5-10KT WINDS WHICH WILL PREVENT THE
DEVELOPMENT OF FOG NEAR DAWN. TEMPS WILL STEADILY DROP OFF IN
COLD AIR ADVECTION OVERNIGHT WITH LOWS NEAR LAMP GUIDANCE, RANGING
FROM THE UPPER 40S TO THE LOWER 50S ACROSS THE AREA.
SATURDAY...DESPITE RELATIVELY LOW CONVECTIVE TEMPS UNDR NW FLOW
ALOFT...LOW INVERSION LEVELS SHOULD PRECLUDE ANY SHRA ON
SATURDAY...ALTHOUGH CU/SC FIELD IS ANTICIPATED. TEMPS WERE
FORECAST USING NAM NMBRS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
DRY WX WL CONT THROUGH SUNDAY WITH BUILDING HIGH PRES. BY
MONDAY...SHRTWV MOVG THRU THE BASE OF ADVNG LONGWAVE TROF IS
FORECAST TO PULL MSTR NWD ALNG THE APPALACHIANS. AS THE SYSTEM IS
STILL PROJECTED AS AN OPEN MID LVL WAVE...WWD EXTENT OF THE RESULTING
PCPN IS QNABLE...AND LIKELY P0PS IN THE LATE DAY WERE CONFINED TO
THE RIDGES FOR NOW.
SHORT TERM TEMPS WERE FORECAST ABOUT 5 DEGREES UNDR THE AVERAGES
USING TWEAKED NAM GUIDANCE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS HAVE COME TO A MUCH BETTER CONSENSUS ON THE OVERALL
PROGRESSION OF THE LONGWAVE TROUGH AND THE EMBEDDED WAVE OUT AHEAD
OF IT THROUGH THE FIRST HALF OF THE PERIOD. THE ECMWF HAS FINALLY
COME ON BOARD WITH THE GFS WITH A BIT MORE AMPLIFIED SYSTEM MOVING
ALONG THE APPALACHIANS BRINGING PRECIPITATION NORTHWARD MONDAY
NIGHT. THE DIFFERENCE COMES IN TIMING OF THE COLD FRONT WITH
THE ECMWF ONLY SLIGHTLY SLOWER. WILL INTRODUCE LIKELY POPS STARTING
MONDAY NIGHT THROUGH MUCH OF TUESDAY WITH BETTER MODEL
AGREEMENT.
NORTHWEST FLOW AND WHAT APPEARS TO BE THE COOLEST TEMPERATURES ALOFT
SO FAR THIS SEASON WILL KEEP TEMPERATURES WELL BELOW NORMAL
WEDNESDAY. THE DETERMINISTIC MODELS MAINTAIN A LONGWAVE TROUGH WITH
EMBEDDED WAVES IN THE FLOW THURSDAY AND FRIDAY WHICH COULD BRING
ROUNDS OF PRECIPITATION AND NEAR NORMAL TEMPERATURES FOR THE
REMAINDER OF THE WEEK.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
THE COLD FRONT IS PUSHING ACROSS WESTERN PA AND WILL MOVE EAST OF
THE MOUNTAIN RIDGES THIS EVENING. A PERIOD OF LOWER IFR/MVFR CEILINGS
CAN BE EXPECTED FOR SEVERAL HOURS BEHIND THE COLD FRONT. SHOWERS
AND LIGHT RAIN CAN EXPECTED BEHIND THE FRONT AS WELL WITH LITTLE
RISK OF THUNDER. NORTHWEST WIND GUSTS OF 25 TO 30 KNOTS CAN BE
EXPECTED IMMEDIATELY BEHIND THE COLD FRONT WITH DIMINISHING WINDS
INTO MIDNIGHT.
ONCE HIGH PRESSURE BUILD IN BEHIND THE FRONT SKIES SHOULD GENERALLY
CLEAR OUT TOWARD THE EARLY MORNING. SOME PATCHY MORNING FOG IS
POSSIBLE IN THE RIVER VALLEYS SATURDAY MORNING BUT IF WINDS REMAIN
ABOVE 5 TO 10 KNOTS FOG WILL BE UNLIKELY.
.OUTLOOK /SATURDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED UNDER HIGH PRESSURE SATURDAY THROUGH THE
FIRST HALF OF MONDAY. THE NEXT CHANCE FOR SHOWERS AND RESTRICTIONS
WILL BE WITH THE APPROACH OF A LOW PRESSURE SYSTEM AND COLD FRONT
MONDAY NIGHT AND TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
315 PM EDT FRI SEP 14 2012
.SYNOPSIS...
DRY CONDITIONS AND SEASONABLE TEMPERATURES WILL CONTINUE AS HIGH
PRESSURE REMAINS ACROSS THE MID ATLANTIC THROUGH TONIGHT. A
WEAK COLD FRONT WILL TRACK ACROSS THE AREA SATURDAY MORNING. HIGH
PRESSURE WILL RETURN SUNDAY BEFORE UNSETTLED WEATHER EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A TOUCH MORE HUMID ACRS THE FA THIS AFTN AS COMPARED TO PAST FEW.
SFC HI PRES CONTS TO WEAKEN THROUGH THE EVE HRS...WHILE CDFNT
APPROACHES FM THE NW. SO FAR...LTL MOVEMENT (N) NOTED ON SCT SHRAS
OVR ECNTRL NC THIS AFTN...17Z/14 RUC KEEPS THOSE SHRAS GENLY FM
ALBEMARLE SND ON S...OTRW XPCG CLR-PCLDY WX E...AND P/MCLDY W.
PCPN CURRENTLY ASSOCIATED W/ THE CDFNT HAS CONTD TO
DIMINISH...APRS THAT HIGHEST PROB FOR ANY SHRAS AND MOST
WIDESPREAD CLDNS WILL RMN NNW OF THE FA THROUGH TNGT. CDFNT TO
PRESS INTO THE CNTRL PORTION OF FA BY 12Z/15. WILL HAVE POPS AOB
14% OVR THE FA OVRNGT.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
CDFNT PRESSES S AND E OF THE FA DURG SAT MRNG...W/ ASSOCIATED
WINDSHIFT TO THE N AS SFC HI PRES BUILDS EWD INTO THE ERN LAKES
RGN. FM SAT NGT THROUGH SUN...S/W MOVG INTO THE LWR MS
VALLEY...AND IN COMBINATION W/ STALLED FNTL BNDRY ACRSS THE
CAROLINAS...THERE WILL BE INCRSD COVERAGE OF CLDNS AND RAINFALL
(FM THE SRN MTNS THROUGH THE TN VLY AND LWR MS VLY. BY SUN
AFTN/EVE...CLDNS AND PCPN MAY BRUSH FAR SSW AREAS OF FA...OTRW SFC
HI PRES RMNS OVR THE RGN...PROVIDING DRY/NR SEASONABLE CONDS.
HI PRES TO BECOME SITUATED OFF THE E CST SUN NGT THROUGH MON...W/
TROUGH ALOFT DIGGING THROUGH THE MIDWEST. AT THE SAME TIME...S/W
WILL BE MOVG E THROUGH THE LWR MS VLY/SE STATES. MDLS GENLY AGREE
W/ INCRSG LLVL/MOIST FLO INTO THE MDATLC STATES...ESP ON
MON...BRINGING A MDT/HI PROB FOR RAINFALL. HI CHCS FOR MON TO BE
CONFINED TO INTR SECTIONS OF FA.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MEDIUM RANGE PERIOD BEGINS WITH SOUTHERN STREAM SHORTWAVE TROUGH
LIFTING NORTHEAST OUT OF THE DEEP SOUTH TOWARDS THE REGION... JUST
AHEAD OF THE NRN STREAM TROUGH POISED TO MOVE ACROSS THE MOUNTAINS
THROUGH TUESDAY. THE MODELS CONTINUE TO HANDLE THE UPPER TROUGH
SIMILARLY, WITH LLVL S WINDS STREAMING MOISTURE-RICH GULF MOISTURE
INTO THE REGION MONDAY NIGHT AND TUESDAY. PROGGED PW AND OMEGA
FIELDS INDICATE THAT OVERRUNNING MOISTURE SHOULD BE STRONG ENOUGH
TO WARRANT 50-60 POP FOR MONDAY NIGHT AND TUESDAY. FRONT APPROACHES
THE REGION TUESDAY NIGHT, WITH THE FRONT LKLY TO CLEAR THE REGION
WEDNESDAY. LOW/MIDLVL FLOW BECOMES W/NW WITH RESULTANT DOWNSLOPE
FLOW SUFFICIENT TO BRING A DRY FORECAST FOR THE LATTER HALF OF THE
WEEK AHEAD.
FOR TEMPERATURES...EXPECT MAXIMA TO AVERAGE NEAR TO JUST BELOW CLIMO
NORMAL FOR THE PERIOD. HIGHS GENERALLY INTO THE 70S TO NR 80. LOWS
IN THE 60S TO NR 70 TUESDAY MORNING...FALLING BACK INTO THE 50S AND
60S TOWARDS THE MIDDLE OF NEXT WEEK, WITH SOME EARLY MORNING LOWS IN
THE UPPER 40S POSSIBLE TOWARDS LATE NEXT WEEK WEST OF RIC.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SCT-BKN CU (4-5K FT) NEXT SEVERAL HOURS SHUD DISSIPATE B4 SUNSET.
WEAKENING FRONTAL BOUNDARY CROSSES FA LATE TONIGHT WITH ONLY SCT-
BKN MID / HIGH LEVEL CLOUDS EXPECTED. DATA SUGGESTS A FEW HOUR PRD
OF IFR CONDITIONS IN FOG AT KSBY PRIOR TO FROPA. WND SHIFT INTO
THE NORTH BEHIND FROPA SAT MORNING WITH CLRG SKIES.
NEXT CHC FOR PRECIP / LWR CIGS / VSBYS WILL BE MON INTO TUE NGT.
&&
.MARINE...
WEAK SFC RIDGING OVER THE NORTHEAST CONTINUES TO SAG INTO THE REGION
THIS AFTERNOON...PROVIDING ONSHORE (E-NE) FLOW ~10 KT, WHICH WILL
CONTINUE THROUGH TONIGHT. SEAS RUNNING 2-4FT NEAR SHORE (1-2FT
BAY/SND). A WEAK (DRY) COLD FRONT WILL PUSH ACRS THE AREA LATE
TONIGHT INTO SAT MORN. BRIEF PERIOD OF SCA EXPECTED OVER THE CHES
BAY SAT MORNING INTO THE AFTN AND SCA HAS BEEN HOISTED FOR SATURDAY
OVER THE CHES BAY AND RIVERS. WINDS DIMINISH WITH SLACKENING
GRADIENT SAT AFTN AND EVENING. HOWEVER, SEAS OVER WATERS LOOK TO
REMAIN IN 3-4 FT RANGE DUE TO INCOMING E-SE SWELL (15-20 SEC)
ARRIVING ALONG THE MID-ATLANTIC COAST BEGINNING SAT EVENING THROUGH
SUNDAY FROM DISTANT TROP STORM NADINE, WHICH IS ORIENTED WELL E/SE
OF BERMUDA. THESE SWELLS WILL ALSO LIKELY RESULT IN CONTINUED
ELEVATED RIP THREAT THROUGH THE WEEKEND.
N-NW WINDS CONTINUE TO DIMINISH SAT NIGHT/SUN AS SFC HIGH PRESSURE
SLIDES OVERHEAD. SFC RIDGE IS EXPECTED TO SLIDE OFF THE COAST LATER
SUN THRU MON. A WARM FRONT THEN LIFTS ACROSS THE AREA DURING MON/MON
NGT, WITH S-SE FLOW 15 KT OR LESS MON-TUE. TIGHTENING PRESSURE
GRADIENT WILL ALLOW FOR INCREASING S/SE FLOW BY THE MIDDLE OF NEXT
WEEK, WITH SCA LIKELY TO BE NEEDED IN ASSOCIATION W/NEXT FRONTAL
PASSAGE TUE/WED OF NEXT WEEK.
&&
.EQUIPMENT...
AT SBY...NORMAL ASOS COMMS REMAIN DOWN AND ARE EXPECTED TO STAY DOWN
FOR SEVERAL DAYS. OBS ARE BEING SENT BY THE TOWER BUT THESE UPDATES
MAY NOT BE RELIABLE SO AMD NOT SKED WILL CONTINUE TO APPEAR IN THE
TAFS.
COMMS WITH ORF ASOS HAVE BEEN RESTORED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT SATURDAY FOR
ANZ630>632-634>638.
&&
$$
SYNOPSIS...ALB/SAM
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...MAM
AVIATION...MPR
MARINE...MAM
EQUIPMENT...AKQ
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1234 PM FRI SEP 14 2012
.SYNOPSIS...
WEAKENING HIGH PRESSURE TO OUR NORTH WILL REMAIN IN PLACE THROUGH
SATURDAY. A COLD FRONT WILL DROP INTO THE AREA SUNDAY BUT SHOULD
QUICKLY DISSIPATE. LOW PRESSURE DEVELOPING ALONG THE GULF COAST
MONDAY WILL MOVE THROUGH THE WESTERN CAROLINAS TUESDAY...DRAGGING A
COLD FRONT ACROSS THE EASTERN CAROLINAS EARLY WEDNESDAY. HIGH
PRESSURE WILL BUILD TO THE COAST FROM THE WEST ON THURSDAY...
BRINGING A RETURN TO DRY WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM FRIDAY...THE SEABREEZE BOUNDARY FROM WILMINGTON
NORTHEAST ALONG HIGHWAY 17 IS LIGHTING UP WITH LIGHT SHOWERS.
VISIBLE SATELLITE IMAGERY SHOWS THE CUMULUS FIELD IS VERY AGITATED
INLAND ACROSS BRUNSWICK...COLUMBUS AND BLADEN COUNTIES AS WELL. I`VE
ADDED SMALL POPS FOR ISOLATED SHOWERS ACROSS THIS AREA BASED ON
SATELLITE IMAGERY AND THE LATEST FEW HRRR RUNS THAT SHOWS CONVECTIVE
POTENTIAL FOCUSING HERE OVER THE NEXT 3-4 HOURS. THE PATCH OF
MORNING LOW CLOUDS ACROSS HORRY...BRUNSWICK AND COLUMBUS COUNTIES
LEFT A HOLE IN THE CUMULUS FIELD DUE TO A DELAYED START TO WARMING
SURFACE TEMPERATURES...AND THIS MAY SERVE TO REDUCE CONVECTIVE
POTENTIAL HERE WITH THE RELATIVELY SHORT DAY LENGTHS THIS TIME OF
YEAR. NO SIGNIFICANT CHANGES TO HIGH TEMPERATURES OR DEWPOINTS ARE
NEEDED. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...
A WEAKENING SURFACE RIDGE EXTENDS ACROSS THE MID-ATLANTIC STATES
WITH NORTHEAST WINDS CONTINUING ACROSS THE CAROLINAS. IN THE UPPER
LEVELS A WEAK UPPER TROUGH MOVING ACROSS THE SOUTHERN APPALACHIANS
HAS DEVELOPED AN EXPANSIVE MID-LEVEL CLOUD CANOPY EXTENDING FROM
SOUTHERN VIRGINIA ACROSS THE WESTERN AND CENTRAL CAROLINAS AND INTO
NORTH GEORGIA. MODEL INITIALIZATION WITH THIS MID-LEVEL MOISTURE IS
TERRIBLE: NO MODEL "SEES" ANY OF THIS MOISTURE IN THE 12K-16KFT
LAYER. THESE CLOUDS SHOULD CONTINUE PUSHING
NORTHEASTWARD...PRODUCING PARTLY CLOUDY SKIES (PERHAPS MOSTLY CLOUDY
FOR A TIME?) ACROSS MOST OF OUR FORECAST AREA AWAY FROM THE
IMMEDIATE COAST.
AS HAS BEEN THE STORY FOR THE PAST THREE DAYS...THE AIRMASS
CONTINUES TO MODIFY WITH ATLANTIC`S INFLUENCE INCREASING ITS IMPACT
ON THE AIRMASS COMING ONSHORE. I THINK IT`S SAFE TO CALL THIS A
SUBTROPICAL AIRMASS NOW WITH DEWPOINTS BACK IN THE UPPER 60S AND
OFFSHORE AIR TEMPERATURES IN THE UPPER 70S. THE MID-LEVEL CLOUD
COVER INLAND SHOULD HAVE LITTLE IMPACT ON OUR HIGHS TODAY AND WE`RE
ANTICIPATING 82-85 DEGREES AWAY FROM THE BEACHES.
WITH STEEP LOW LEVEL LAPSE RATES AND LOADS OF LOW-LEVEL MOISTURE A
LOW CUMULUS SHOULD DEVELOP IN THE NEXT FEW HOURS. SOME OF THESE
WITHIN 30-40 MILES OF THE COAST COULD GROW INTO SMALL SHOWERS...AND
I`LL MAINTAIN THE 20 POP FOR THIS POTENTIAL. THE STEERING FLOW ALOFT
IS RATHER WEAK AND ONLY A SLIGHT WESTWARD DRIFT OF ANY SHOWERS IS
EXPECTED.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...WEAKENING COLD FRONT WILL MOVE INTO THE
AREA FROM THE NORTHWEST LATE SAT. LACK OF UPPER LEVEL
SUPPORT...THE PARENT LOW WILL BE IN EASTERN CANADA...AND ABUNDANT
DRY AIR WILL KEEP ITS PASSAGE DRY. AHEAD OF THE FRONT THE DRY AIR
COMBINED WITH WEAK MID LEVEL SUBSIDENCE WILL LIMIT CONVECTION SAT
AFTERNOON. WESTERLY FLOW ALOFT SAT NIGHT WILL ADVECT DEEPER
MOISTURE OVER THE LOWER MS VALLEY INTO THE REGION FOR SUN. THE
DEEP MOISTURE COMBINED WITH DIURNAL HEATING...REMNANTS OF
DISSIPATING COLD FRONT...AND PASSAGE OF SHORTWAVE SHOULD GENERATE
SOME DEEPER CONVECTION SUN. HOWEVER...HAVE LOW CONFIDENCE IN THE
LOCATION AND STRENGTH OF SHORTWAVE AND GIVEN THE FLAT PATTERN
ALOFT WILL HOLD ONTO SLIGHT CHANCE POP FOR NOW. LOW LEVEL RETURN
FLOW STARTS TO DEVELOP SUN NIGHT AS AS SURFACE HIGH TO THE NORTH
SLIPS OFF THE MID-ATLANTIC COAST. TEMPERATURES WILL BE NEAR CLIMO
ON SAT AND SAT NIGHT FALLING SLIGHTLY BELOW SUN AND SUN NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...SOUTHERN STREAM SHORTWAVE TROUGH EMERGING
FROM EAST TX AT THE START OF THE PERIOD WILL BE ACCELERATED
NORTHEAST TUE BY AMPLIFYING 5H TROUGH OVER THE MS VALLEY. STILL
SEEING SOME DIFFERENCES WITHIN THE MEDIUM RANGE GUIDANCE BUT
OVERALL AGREEMENT IS GOOD. MON/TUE LOOK WET WITH DEEP SOUTH TO
SOUTHWEST FLOW PUSHING PLENTY OF GULF MOISTURE OVER THE SOUTHEAST.
IN ADDITION DIVERGENT FLOW ALOFT AND STRONG LOW LEVEL JETTING
DEVELOP LATE MON AND CONTINUE FOR MUCH OF TUE. A SERIES OF
SHORTWAVES WILL MOVE ACROSS THE SOUTHEAST...ENHANCING CONVECTION
AS THEY APPROACH AND SUPPRESSING ACTIVITY AS THEY EXIT. TIMING
HOWEVER REMAINS DIFFICULT...THUS POP FORECAST WILL BE TEMPERED AND
LESS PRECISE. HIGHLY AMPLIFIED 5H TROUGH PUSHES COLD FRONT THROUGH
THE AREA TUE NIGHT OR WED WITH DRIER/COOLER AIR TRYING TO BUILD IN
BEHIND THE BOUNDARY. LATE NEXT WEEK 5H TROUGHING SETS UP OVER THE
EASTERN HALF OF THE COUNTRY. IF THE FRONT ENDS UP PARALLEL TO THE
FLOW ALOFT WITH A MECHANISM TO EJECT IT NORTHEAST IT WOULD REMAIN
STALLED JUST OFF THE SOUTHEAST COAST THROUGH THE END OF THE
PERIOD. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO THROUGH
THE PERIOD...LOW TO MID 80S AND LOW TO MID 60S.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...ISOLATED SHOWERS ALONG THE SEA BREEZE BOUNDARY THIS
AFTERNOON WILL PUSH ACROSS THE WILMINGTON VICINITY AND MAY AFFECT
CRE/MYR AND POSSIBLY LBT BY LATE AFTERNOON. VERY ISOLATED COVERAGE
ONLY WARRANTS A VCSH. SURFACE WINDS WILL BE FAIRLY LIGHT TODAY SOUTH
OF A WEAKENING HIGH PRESSURE RIDGE. TONIGHT...GOOD RADIATIONAL
COOLING CONDITIONS WILL BRING FOG INTO THE PICTURE LATE. MODELS ARE
FAVORING THE INLAND TERMINALS WITH MORE FAVORABLE LOW-LEVEL MOISTURE
PROFILES. WILL GO WITH INTERMITTENT IFR THERE. SATURDAY...A
REINFORCING PUSH OF HIGH PRESSURE MOVES IN ALONG A WASHED OUT COLD
FRONT. WINDS WILL BE LIGHT AND MAINLY NORTHEASTERLY.
THE EXTENDED OUTLOOK THROUGH WEDNESDAY...AN INCREASED CHANCE OF
PRECIPITATION SUNDAY. SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS
MONDAY THROUGH WEDNESDAY...MOST NUMEROUS TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM FRIDAY...NORTHEAST WINDS CONTINUE IN THE 10-13 KNOT
RANGE ON THE NOON OBSERVATIONS. THERE ALSO HAVE BEEN NO CHANGE IN
SEA HEIGHTS AT THE AREA BUOYS. NO CHANGES IN THE FORECAST ARE
NEEDED. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...
A WEAKENING SURFACE RIDGE REMAINS NORTH OF THE CAROLINAS WITH
NORTHEAST WINDS COVERING THE AREA. THE FLOW BUCKLES ALONG THE
GEORGIA AND SOUTHERN SOUTH CAROLINA COAST WHERE A WEAK COASTAL
TROUGH APPEARS TO HAVE DEVELOPED. THIS FEATURE SHOULD REMAIN TOO FAR
SOUTH OF OUR FORECAST AREA FOR ANY IMPACTS LOCALLY. NORTHEAST WINDS
MAY BEND AROUND TO THE EAST LATER TODAY WITH A WEAK SEABREEZE...BUT
THERMAL CONTRASTS FROM THE MARINE ENVIRONMENT TO INLAND SHOULD BE
TOO WEAK FOR ANY SIGNIFICANT INCREASE IN WIND SPEEDS. WINDS
CURRENTLY AVERAGE 10-13 KNOTS AND SHOULD REMAIN THERE THROUGH THE
DAY.
SEAS RANGE FROM 3-4 FT AT THE OFFSHORE BUOYS IN A JUMBLED MIX OF 4-7
SECOND LOCAL WIND WAVES AND A MUCH SMALLER 10-13 SECOND LONG PERIOD
SWELL ADVECTING IN FROM THE DEEP ATLANTIC. ISOLATED SHOWER ACTIVITY
OFFSHORE EAST OF CAPE FEAR SHOULD WEAKEN AS IT APPROACHES THE
COAST...BUT WE MAY GENERATE NEW SHOWERS ALONG THE SEABREEZE BOUNDARY
THIS AFTERNOON THAT MAY AFFECT THE BEACHES AND ADJACENT NEARSHORE
WATERS.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...LIGHT NORTHEAST FLOW EARLY SAT WILL BRIEFLY
BECOME SOUTHERLY AHEAD OF WEAK COLD FRONT. FRONT PUSHES SOUTHEAST OF
THE WATERS SAT NIGHT INTO SUN WITH A BRIEF BUT NOTICEABLE NORTHEAST
SURGE BEHIND IT ON SUN. HIGH PRESSURE BUILDING IN BEHIND THE FRONT
WILL SLIDE OFF THE MID-ATLANTIC COAST SUN NIGHT WITH NORTHEAST FLOW
GRADUALLY VEERING TO EASTERLY. SPEEDS WILL BE UNDER 10 KT FOR MUCH
OF THE PERIOD WITH SEAS 2 TO 4 FT.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...LIGHT SOUTHEAST FLOW AT THE START OF THE PERIOD
INCREASE IN SPEEDS MON IN RESPONSE TO TIGHTENING PRESSURE GRADIENT.
SPEEDS START OUT AROUND 10 KT BUT WILL END UP 10 TO 15 KT MON
AFTERNOON. SPEEDS INCREASE TO 15 TO 20 KT BY TUE AND VEER TO
SOUTHWESTERLY. SEAS 2 TO 4 FT MON WILL BUILD IN RESPONSE TO INCREASE
IN SOUTHERLY FLOW. TUE SEAS REACH 3 TO 5 FT WITH SOME ISOLATED 6 FT
POSSIBLE NEAR 20 NM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
153 PM EDT FRI SEP 14 2012
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTHEAST ACROSS THE REGION TODAY. HIGH
PRESSURE WILL BUILD SOUTH INTO THE LOWER GREAT LAKES AND OHIO
VALLEY TONIGHT. THE HIGH WILL REMAIN ACROSS THE AREA THROUGH THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PCPN IS CONTINUING TO PROGRESS EAST ACROSS NORTHWEST PORTIONS OF
OUR FA. THERE DOES APPEAR TO BE SOME WEAKENING OF THE PCPN IN THE
PAST FEW RADAR IMAGES...BUT THE LATEST HRRR IS SILL TRYING TO PUSH
PCPN ACROSS OUR ENTIRE FA. WILL NOT GO QUITE AS AGGRESSIVE AS THE
HRRR WOULD SUGGEST BUT WILL STILL BUMP UP POPS A BIT MORE ACROSS
THE NORTH. SOME UNCERTAINTY EXISTS AS TO HOW MUCH CLEARING WILL
MAKE IT INTO OUR NORTHWEST LATER THIS AFTERNOON. HOWEVER...WITH
CLOUDS THROUGH AT LEAST A GOOD PORTION OF THE AFTERNOON AND
A DEVELOPING CAA PATTERN...WILL DROP HIGHS DOWN INTO THE MID TO
UPPER 60S THERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE WILL BUILD SOUTH INTO THE GREAT LAKES AND
OHIO VALLEY TONIGHT. SKIES WILL CLEAR FROM THE NORTH AS
DRIER...COOLER AIR SETTLES INTO THE REGION. RADIATIONAL COOLING
WILL BE IN FULL FORCE AND EXPECT OVERNIGHT LOWS TO RANGE FROM THE
LOWER 40S NW...AND IN SOME OF THE COLDER SPOTS OF CENTRAL OHIO...TO
THE LOWER 50S SOUTH.
UNDER A WNW FLOW PATTERN ALOFT...SURFACE HIGH PRESSURE WILL
REMAIN OVER THE REGION THROUGH SUNDAY. A FEW CUMULUS CLOUDS MIXED
WITH CIRRUS CAN BE EXPECTED DURING THE DAYTIME WITH MAINLY CLEAR
SKIES AT NIGHT. HIGHS WILL RANGE FROM THE LOWER TO MID 70S ON
SATURDAY...MODERATING SLIGHTLY INTO THE MID AND UPPER 70S ON SUNDAY.
RADIATIONAL COOLING WILL OCCUR ONCE AGAIN SATURDAY NIGHT WITH LOWS
RANGING FROM THE LOWER 40S TO THE LOWER 50S.
MODELS ARE COMING INTO BETTER AGREEMENT IN TERMS OF THE NEXT
WEATHER SYSTEMS TO AFFECT THE REGION INTO THE FIRST PART OF THE
WEEK. HAVE TAKEN A BLEND OF THE ECMWF AND THE GFS WHICH INDICATE
THAT A LONG WAVE TROUGH WILL DIG SOUTH INTO THE GREAT LAKES AND
OHIO VALLEY. MEANWHILE...UPR LVL ENERGY NEAR THE DESERT SW WILL
EJECT NE INTO TOWARD THE TN AND OHIO VALLEYS. IT IS STILL UNCLEAR
ON HOW MUCH MOISTURE WILL BE PULLED NORTHWARD INTO THE REGION FROM
THIS SYSTEM AS THE LONG WAVE TROUGH DIGS SOUTHEAST. HAVE RAISED
POPS FOR ALL LOCATIONS FOR MONDAY INTO MONDAY NIGHT...BUT THIS
VERY WELL COULD GO LIKELY...ESPECIALLY FOR THE SE HALF OF THE
AREA. GIVEN CLOUDS AND CHANCES FOR PCPN...HAVE LOWER HIGHS ON
TUESDAY INTO THE LOWER AND MID 70S.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS THE LONG WAVE TROUGH DIGS SOUTHEAST INTO THE REGION ON
TUESDAY...A COLD FRONT WILL PUSH SOUTHEAST THROUGH THE AREA. THIS
FRONT WILL PROVIDE FOR ANOTHER FOCUS OF SHOWERS. THE FRONT WILL
PUSH EAST OF THE REGION TUESDAY NIGHT INTO WEDNESDAY...ALLOWING
HIGH PRESSURE OF CANADIAN ORIGIN TO SET UP OVER THE OHIO VALLEY ON
WEDNESDAY. DAYTIME HIGHS WILL COOL INTO THE 60S BY WEDNESDAY...WHICH
WILL BE SOME 10 TO 15 DEGREES BELOW NORMAL FOR MID SEPTEMBER.
HIGH PRESSURE WILL THEN MOVE EAST OF THE AREA ON THURSDAY AS A
WEAK UPPER LEVEL DISTURBANCE PUSHES ACROSS THE GREAT LAKES.
HAVE GONE WITH A SLIGHT CHANCE OF SHOWERS WITH THIS SYSTEM.
TEMPERATURES WILL MODERATE INTO THE LOWER AND MID 70S.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
COLD FRONT IS NOW JUST SOUTHEAST OF THE I-71 CORRIDOR AND HAS
PUSHED THROUGH ALL OF THE TAF SITES. THE POST FRONTAL PCPN HAS
BEEN GRADUALLY TAPERING OFF AND THIS TREND SHOULD CONTINUE
THROUGH THE REMAINDER OF THE AFTERNOON. THIS MAY STILL RESULT IN
A FEW RAIN SHOWERS OR SPRINKLES...ESPECIALLY AT KCMH AND
KLCK...BUT OVERALL THE PCPN THREAT SHOULD BE DECREASING. MEANWHILE...LOWER
MVFR CIGS ARE WORKING IN BEHIND THE FRONT. MODELS ARE INDICATING
THAT THESE WILL SLOWLY LIFT AS THEY PUSH EAST THROUGH THE REST OF
THE AFTERNOON...BUT WE WILL LIKELY STILL SEE A COUPLE HOUR PERIOD
OF MVFR CIGS. OTHERWISE...DRIER AIR WILL MOVE IN OVERNIGHT...ALLOWING
FOR SKIES TO BECOME MOSTLY CLEAR THIS EVENING. DESPITE THE
CLEARING SKIES AND DECREASING WINDS...THINK DRIER AIR WILL HELP
LIMIT THE BR AT KLUK LATER TONIGHT.
.OUTLOOK...MVFR CEILINGS ARE POSSIBLE ON MONDAY NIGHT AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...JGL
SHORT TERM...HICKMAN
LONG TERM...NOVAK
AVIATION...JGL