Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/11/12
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
945 PM EDT MON SEP 10 2012
.UPDATE (REST OF TONIGHT)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS OUR FORECAST AREA UNDER
DEEP WESTERLY FLOW BETWEEN A RIDGE OF UPPER LEVEL HIGH PRESSURE TO
OUR SOUTH AND A PASSING LONGWAVE TROUGH TO OUR NORTHEAST. ASSOCIATED
WITH THIS PASSING TROUGH...A SURFACE FRONT HAS SLIPPED SOUTHWARD
INTO THE NORTHERN FL PENINSULA ZONES. THIS FRONT IS PROGGED BY NWP
GUIDANCE TO CONTINUE SLOWLY SINKING SOUTH ACROSS THE REGION TONIGHT
INTO TUESDAY. MOST OF THE SHOWER/STORM ACTIVITY AS FADED IN THE PAST
FEW HOURS SINCE SUNSET...HOWEVER WITH THIS FOCUS MECHANISM IN THE
VICINITY...CAN NOT RULE OUT A FEW ISOLATED SHOWERS AND WILL KEEP A
20% POP IN THE GRIDS OVER LAND. BETTER CHANCES FOR SHOWERS AND
STORMS LATER TONIGHT WILL EXIST OVER THE COASTAL WATER ZONES. HAVE
MADE JUST A FEW MINOR ADJUSTMENTS TO THE POP GRIDS AND TEMPERATURE
CURVE TO MATCH CURRENT TRENDS...OTHERWISE INHERITED FORECAST IS ON
TRACK AND NO SIGNIFICANT UPDATES ARE ANTICIPATED.
&&
.PREVIOUS DISCUSSION (TUESDAY - WEDNESDAY)...
EXITING EAST COAST TROUGH WILL BE REPLACED BY BROAD MID LEVEL RIDGING
OVER THE SOUTHEASTERN U.S. AND FLORIDA DURING THE SHORT TERM PERIOD.
ATTENDANT SURFACE HIGH BUILDING DOWN THE EASTERN SEABOARD WILL HELP
TO PUSH THE STALLED FRONTAL BOUNDARY NOW ACROSS THE SOUTH CENTRAL
PENINSULA SOUTH OF THE REGION BY LATER TUESDAY WITH AN INCREASING
NORTHEAST TO EASTERLY WIND FLOW PRODUCING BREEZY CONDITIONS ACROSS
THE AREA. THIS WIND FLOW WILL BRING IN SOME DRIER AIR WITH LOWER
RAIN CHANCES TO EAST CENTRAL AND NORTHERN ZONES ON TUESDAY...WITH
HIGHEST RAIN CHANCES CONTINUING ACROSS SOUTHWEST FLORIDA WHERE THE
DEEPEST MOISTURE AND FRONTAL BOUNDARY WILL RESIDE.
ON WEDNESDAY DEEPEST MOISTURE AND REMNANT FRONTAL BOUNDARY WILL
MOVE FURTHER TO THE SOUTH AS SURFACE HIGH PRESSURE TAKES HOLD
OVER THE MID ATLANTIC. A BREEZY NORTHEAST TO EAST WIND FLOW AROUND
THE SURFACE HIGH TO THE NORTH WILL ALLOW ATLANTIC MOISTURE TO ADVECT
WEST INTO THE FORECAST AREA DURING THE DAY. THIS MOISTURE COMBINED
WITH DAYTIME HEATING WILL LIKELY SUPPORT SOME LOW TOPPED SHOWERS AND
A FEW STORMS ACROSS THE REGION DURING THE AFTERNOON AND EARLY EVENING
HOURS...AND WILL DEPICT ISOLATED TO LOW END SCATTERED RANGE POPS.
THE BREEZY EASTERLY FLOW WILL ALLOW TEMPERATURES TO CLIMB BACK TO
ABOVE NORMAL WITH DAYTIME HIGHS CLIMBING INTO THE LOWER TO MID 90S
WITH NIGHTTIME LOWS IN THE 70S.
&&
.AVIATION...
LINGERING SHOWERS AND STORMS THROUGH 03Z SHOULD MAINLY IMPACT LAL.
WINDS BECOME LIGHT NORTHEAST OVERNIGHT THEN AROUND 10 KNOTS TUESDAY.
EXPECT AFTERNOON STORMS AGAIN TUESDAY WITH HIGHEST COVERAGE AROUND
FMY AND RSW.
&&
.MARINE...
HIGH PRESSURE BUILDING DOWN THE EASTERN SEABOARD IN THE WAKE OF THE
COLD FRONT WILL HELP TO TIGHTEN THE PRESSURE GRADIENT ACROSS THE
GULF WATERS TONIGHT THROUGH THE REMAINDER OF THE WEEK WITH A
NORTHEAST TO EASTERLY WIND FLOW INCREASING TOWARD EXERCISE CAUTION
OR LOW END SMALL CRAFT RANGE WITH SOME ROUGH BOATING CONDITIONS
LIKELY TO DEVELOP OVER THE GULF WATERS THROUGH THE PERIOD. GIVEN
THESE EXPECTED TRENDS...WILL HOIST SCA FOR THE OFFSHORE WATERS FROM
TARPON NORTH IN THE 403 PM COASTAL PACKAGE...WITH THIS ADVISORY
LIKELY EXPANDING SOUTHWARD INTO THE REMAINDER OF THE WATERS DURING
THE COMING DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 89 73 90 / 20 40 10 20
FMY 75 89 73 91 / 20 50 20 20
GIF 73 91 72 90 / 20 40 10 30
SRQ 76 91 72 93 / 20 50 20 20
BKV 69 90 69 90 / 20 30 10 20
SPG 78 89 76 90 / 20 40 20 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY FROM 2 AM TO 10 AM EDT TUESDAY FOR
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
PREVIOUS DISCUSSION..MCMICHAEL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1238 AM EDT SUN SEP 9 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 426 PM EDT SAT SEP 8 2012
MAIN FOCUS OF THE SHORT TERM IS THE STRONG SHORTWAVE SLIDING SSE
THROUGH NE MN AND WRN LK SUPERIOR AND THE ASSOCIATED SFC COLD FRONT.
AHEAD OF THIS SHORTWAVE...AREA OF SHOWERS HAS DROPPED OUT OF CANADA
THIS MORNING AND INTO FAR WRN UPPER MI. EXPECT THESE SHOWERS TO
CONTINUE TO SLIDE TO THE SE OVER THE COUNTIES NEAR THE WI BORDER
THROUGH THE REST OF THIS AFTN...ASSOCIATED WITH THE H850-500
Q-VECTOR CONV. BEHIND THIS INITIAL AREAS OF SHOWERS AND THE
FRONT...SCATTERED SHOWERS HAVE DEVELOPED UNDER THE CENTER OF THE
SHORTWAVE AND ASSOCIATED WITH AREA OF STEEP MID LVL LAPSE RATES.
THESE SHOWERS SHOULD CONTINUE TO THE SSE AND LARGELY MISS THE
CWA...BUT COULD SEE SOME SCATTERED SHOWERS OVER THE WEST UNTIL
DIURNAL HEATING IS LOST AND THE SHORTWAVE SLIDES S OF THE CWA.
ATTENTION THEN TURNS TO POTENTIAL LK ENHANCED SHOWERS AND CLOUDS FOR
TONIGHT. RUC ANALYSIS IS SHOWING THAT H850 TEMPS HAVE WARMED A
DEGREE OR TWO FROM THIS MORNING...TOWARDS 6-7C OVER THE WEST AHEAD
OF THE SHORTWAVE. ONCE THIS WAVE AND THE SFC FRONT SLIDE SE OF THE
AREA...EXPECT H850 TEMPS TO FALL TOWARDS 5C BY THIS EVENING AND THEN
4C BY 12Z SUN. WITH LK SUPERIOR TEMPS IN THE 17-21C RANGE...THIS
SHOULD PROVIDE DECENT DELTA-T VALUES FOR LK ENHANCED SHOWERS/CLOUDS.
THE MAIN QUESTION FOR TONIGHT INTO SUN MORNING IS THE AMNT OF
MOISTURE AND IT/S LOCATION. WITH THE TRACK OF THE SHORTWAVE AND
MOISTURE UPSTREAM INTO ONTARIO...EXPECT FAR WRN UPPER MI TO SEE THE
BEST OPPORTUNITY FOR LK ENHANCED SHOWERS UNDER THE NRLY BL FLOW.
THAT AREA WILL BE AIDED BY COASTAL CONVERGENCE AND UPSLOPE FLOW...SO
HAVE HIGH END CHANCE POPS THROUGH MUCH OF THE NIGHT. WITH A SLIGHT
DELAY TO THE COLDEST TEMPS...MAY SEE A SHORT BREAK IN THE SHOWERS
AFTER THE SUN GOES DOWN AND BEFORE THE COLD AIR ARRIVES. FARTHER NE
IS A LITTLE MORE UNCERTAIN. MODELS SHOWING H850-700 DRY AIR DROPPING
S FROM CNTRL ONTARIO AND OVER CNTRL/ERN LK SUPERIOR THIS EVENING AND
OVER CNTRL/ERN UPPER MI OVERNIGHT. WITH THE LACK OF CU THAT HAS
DEVELOPED NE OF THUNDER BAY...THAT SEEMS FAIRLY REASONABLE.
BUT...H925-850 MOISTURE AND STEEP LAPSE RATES OVER LK SUPERIOR WITH
THE NRLY FLOW SHOULD STILL PRODUCE ISOLATED TO POTENTIALLY SCATTERED
LK ENHANCED SHOWERS OVER THE NCNTRL CWA WITH THE LIMITED CLOUD DEPTH
KEEPING THEM LIGHT. ALL OF THESE SHOWERS MAY BE HELPED BY A
SECONDARY SHORTWAVE FROM NW ONTARIO MOVING THROUGH OVERNIGHT.
FOR TOMORROW...WITH LINGERING LLVL MOISTURE AND 3-4C H850
TEMPS...THE NNW WIND FAVORED LOCATIONS SHOULD SEE PARTLY/MOSTLY
CLOUDY SKIES THROUGH THE MORNING HOURS. STILL LINGERED LIGHT SHOWERS
THROUGH THE MORNING...BUT LIMITED MOISTURE DEPTH SUPPORTS ONLY
HAVING SLIGHT CHANCES. OVER THE CNTRL/EAST IN THE AFTN...MOISTURE
THAT IS CURRENTLY OVER NW ONTARIO SHOULD DROP OVER THE ERN LK AND
WITH THE COLD TEMPS REINFORCE THE CLOUD DECK. NCEP WRF NMM/ARW RUNS
HAVE SHOWN THE POTENTIAL FOR SHOWERS WITH THIS WAVE...BUT CONCERNED
DRIER AIR ALOFT WILL KEEP CLOUDS FROM DEVELOPING TOO MUCH. FARTHER
WEST...HIGH PRESSURE BUILDING IN UNDER THE UPPER RIDGING WILL HELP
BRING DRIER AIR INTO THE AREA AND DECREASE THE CLOUDS DURING THE
AFTN AND LEAD TO CLEARING AFTER 21Z.
FINALLY...WITH THE NORTHERLY WINDS CREATING 3-5FT WAVES
TOMORROW...EXPECT A MODERATE TO HIGH RISK OF RIP CURRENTS TO
CONTINUE TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 426 PM EDT SAT SEP 8 2012
MEDIUM RANGE GUIDANCE CONTINUES TO BE IN GENERAL AGREEMENT ON THE
BIG PICTURE OVER THE NEXT 7 DAYS AS IT PERTAINS TO UPPER MI. AFTER
THIS WEEKENDS TROF...PATTERN WILL BECOME MORE PROGRESSIVE NEXT WEEK.
THE TROF DOMINATING THE GREAT LAKES THIS WEEKEND WILL BE FOLLOWED BY
RIDGING EARLY IN THE WEEK...A TROF FOR THE MID/LATE PORTION OF THE
WEEK...AND ANOTHER TROF LATE NEXT WEEKEND. THE EVOLUTION/STRUCTURE
OF THE MID/LATE WEEK TROF REMAINS THE MAIN AREA OF MODEL
DISAGREEMENT. WITH A PROGRESSIVE PATTERN...TEMPS WILL SHOW A FAIR
AMOUNT OF VARIATION OVER THE NEXT 7 DAYS. TEMPS A LITTLE BLO NORMAL
THRU THE WEEKEND WITH TROFFING OVER THE GREAT LAKES WILL TRANSITION
TO STRONG WARMING/ABOVE NORMAL TEMPS EARLY IN THE WEEK AHEAD OF THE
NEXT APPROACHING TROF. GRADUAL COOLING WILL OCCUR MIDWEEK...LEADING
TO TEMPS AROUND NORMAL LATE IN THE WORK WEEK AS MID/UPPER LEVEL
TROF PASSES. TEMPS WILL THEN BEGIN TO REBOUND FOR THE START OF NEXT
WEEKEND. AS FOR PCPN...THIS WILL BE AN OVERALL DRY PERIOD DUE TO
LACK OF GULF MOISTURE TRANSPORT TO THE UPPER LAKES AND DUE TO MAIN
FORCING PASSING N OF THE AREA WHEN SHORTWAVES PASS.
BEGINNING SUN NIGHT...WITH SFC HIGH PRES RIDGE PASSING ACROSS THE
AREA...CLR SKIES AND PRECIPITABLE WATER 45-65PCT OF NORMAL...A GOOD
RADIATIONAL COOLING NIGHT IS EXPECTED. MINS ON THE LOW SIDE OF AVBL
GUIDANCE LOOK ON TRACK. TRADITIONAL INTERIOR COLD SPOTS SHOULD DROP
TO THE UPPER...POSSIBLY MID...30S. MIGHT SEE A LITTLE FROST.
AS MID LEVEL RIDGE SHIFTS TO THE UPPER LAKES MON...WAA WILL BE
UNDERWAY. LOW-LEVEL JET/STRONGEST PUSH OF WARMING IS WELL TO THE NNW
MON...SO PCPN IS NOT A CONCERN. TEMPS SHOULD REBOUND INTO THE 70S
UNDER WAA PATTERN.
AS THE MID LEVEL RIDGE SHIFTS E TUE AND NEXT TROF BEGINS TO MOVE OUT
OVER THE NRN PLAINS...850MB THERMAL RIDGE (TEMPS OF 16-19C) WILL
TRANSLATE OVER THE AREA. ALTHOUGH THERE REMAINS SOME CONCERN WITH
MID/HIGH CLOUD COVERAGE TUE...THERMAL RIDGE AND BREEZY S-SW WINDS
WILL LEAD TO A WARM DAY FOR EARLY/MID SEPT...ESPECIALLY OVER THE W
HALF. WILL STAY WITH HIGH TEMPS MAINLY LOW/MID 80S...ABOVE ALL
GUIDANCE IN MOST AREAS. NOT TOTALLY OUT OF THE QUESTION THAT SOME OF
THE DOWNSLOPE AREAS OVER THE W TOWARD LAKE SUPERIOR COULD FLIRT WITH
90F IF THE DAY ENDS UP SUNNY. COOLER READINGS WILL BE OVER THE E
WITH FLOW UP LAKE MICHIGAN. WITH LOW-LEVEL JET TRANSLATING ACROSS
THE AREA...THERE IS A VERY SMALL POTENTIAL FOR SOME CONVECTION...BUT
LACK OF BETTER MOISTURE MINIMIZES THE POTENTIAL.
MEDIUM RANGE GUIDANCE HAS CONTINUED TO SLOW DOWN SLIGHTLY THE COLD
FRONT ASSOCIATED WITH THE INCOMING MID LEVEL TROF MIDWEEK. IT NOW
APPEARS FRONT WILL BE CROSSING THE AREA DURING THE DAY WED. WITH
BEST DEEP LAYER FORCING PASSING WELL TO THE N AND WITH A LACK OF A
GOOD GULF MOISTURE CONNECTION...THERE SHOULDN`T BE MUCH PCPN
ASSOCIATED WITH THE FRONT. HOWEVER...WITH THE UPPER TROF TAKING ON A
POSITIVE TILT FROM HUDSON BAY TO THE NRN PLAINS THRU THU...THE
SUPPORTING SW-NE ORIENTED UPPER JET WILL SLOWLY TRANSLATE EASTWARD.
AS IT DOES...RIGHT ENTRANCE UPPER DIVERGENCE WILL BEGIN TO OVERLAY
THE LOW-LEVEL FRONT...LIKELY LEADING TO A RIBBON SHRA EVENTUALLY
DEVELOPING ALONG/BEHIND SFC FRONT AS SUGGESTED BY THE
GFS/ECMWF/GLOBAL GEM. THUS...PLAN TO MAINTAIN SCHC POPS OVER THE FAR
W LATE TUE NIGHT INTO WED WITH SCHC POPS EXPANDING INTO THE CNTRL
WED AND THEN CHC POPS OVER THE E HALF WED NIGHT. INSTABILITY IS VERY
LIMITED...SO POTENTIAL OF THUNDER IS MINIMAL. LINGERED SCHC POPS
OVER ALL BUT THE FAR W THU GIVEN MODEL TRENDS...BUT MAY NEED TO
INCREASE THU POPS TO CHC IF CONSISTENCY DEVELOPS FOR SLOW FRONTAL
MOVEMENT AND AN INCREASED POST FRONTAL PCPN BAND WITH TIME DUE TO
UPPER JET.
SINCE YESTERDAY`S RUNS...GFS/ECMWF HAVE TRENDED COOLER FOR FRI AS
THE MID/UPPER LEVEL TROF PASSES (850MB TEMPS 3-5C TO START THE DAY).
AS A RESULT...TEMPS WILL BE BACK AROUND NORMAL MID SEPT VALUES (60S
FOR HIGHS). MIGHT BE SOME LAKE EFFECT -SHRA FRI MORNING IN THE
CHILLY NW FLOW. OTHERWISE...DRY WEATHER IS EXPECTED FRI. HOWEVER...
IT IS NOTED THAT THE 00Z GFS AND NOW THE 12Z ECMWF SHOW ENERGY IN
THE SRN PORTION OF PASSING TROF SEPARATING OUT AND LEADING TO A MID
LEVEL LOW TRACKING INTO THE UPPER LAKES FRI INTO EARLY SAT. GIVEN
THE VERY INCONSISTENT SIGNAL...WILL IGNORE THIS IDEA FOR NOW. WILL
BE SOMETHING TO KEEP IN MIND WHICH MAY CHANGE THE CURRENT DRY FCST
TO A POSSIBLE GOOD SOAKING. IN THE ABSENCE OF THE POSSIBLE MID LEVEL
LOW...DRY WEATHER/WARMING IS EXPECTED SAT AS WEAK MID LEVEL RIDGE
ARRIVES. NEXT SHORTWAVE TROF SHOULD ARRIVE SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1237 AM EDT SUN SEP 9 2012
COLDER AIR MOVING IN BEHIND A FRONT WILL BRING THE CHANCE FOR SOME
LAKE EFFECT CLOUDS AND RAIN SHOWERS. EXPECT THE BEST CHANCE FOR
LOWER CIGS AND SHRA AT KIWD...CLOSER TO THE MORE FAVORABLE LOW LEVEL
MOISTURE. KSAW MAY ALSO SEE A PERIOD OF LOWER CIGS BUT CONFIDENCE IS
LOWER...SO LEFT WITH CIGS JUST ABOVE MVFR. DRIER AIR AND A LESS
FAVORABLE FETCH SHOULD MAINTAIN VFR CONDITIONS AT CMX. AS DRIER AIR
MOVES IN EXPECT ANY REMAINING BKN CIGS TO DISSIPATE BY LATE SUNDAY
MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT SAT SEP 8 2012
A SFC TROUGH DROPPING SE ACROSS LAKE SUPERIOR THIS EVENING WILL
BRING A REINFORCING SHOT OF COLD AIR AND STRENGTHEN THE NNW WINDS
ACROSS LAKE SUPERIOR. THE HIGHEST GUSTS...TO 30KTS...WILL BE SEEN
OVER FAR WRN LK SUPERIOR...WILL THE REST OF THE LAKE WILL SEE
15-25KTS TONIGHT INTO TOMORROW. HIGH PRESSURE WILL BUILD OVER THE
UPPER GREAT LAKES TOMORROW AND LEAD TO WEAKENING WINDS SUN AFTN AND
SUNDAY NIGHT. AS THE HIGH QUICKLY SHIFTS TO THE LOWER GREAT LAKES
ON MONDAY...SOUTHERLY WINDS WILL INCREASE AND PRODUCE A PERSISTENT
PERIOD OF 15-25KT WINDS THROUGH TUESDAY NIGHT WHEN A COLD FRONT
PUSHES ACROSS LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1213 AM EDT SUN SEP 9 2012
.SYNOPSIS...
ISSUED AT 252 PM EDT SAT SEP 8 2012
EXPECT SHOWERS AND ISOLATED THUNDERSTORMS NEAR LAKE MICHIGAN
TONIGHT. THAT ACTIVITY WILL DIMINISH BY MID MORNING SUNDAY.
OTHERWISE EXPECT COOLER WEATHER TO PREVAIL INTO THE BEGINNING OF
THE WEEK. A WARMING TREND WILL BEGIN BY TUESDAY THAT WILL LAST
INTO THE END OF THE WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 252 PM EDT SAT SEP 8 2012
THE PRIMARY FORECAST CONCERN IS THE AREA OF SHOWERS MOVING
SOUTHEAST FROM WESTERN UPPER MICHIGAN AND HOW IT WILL IMPACT
SOUTHWEST LOWER MICHIGAN OVERNIGHT AS IT MOVES THROUGH.
OTHERWISE...I EXPECT TEMPERATURES TO FALL INTO THE 30S NEAR ROUTE
10 EAST OF THE LAKE SHORE SUNDAY NIGHT. AN EARLY TASTE OF FALL FOR
SURE.
A STRONG SHORTWAVE... WELL DEFINED ON THE WATER VAPOR LOOPS...
WILL CONTINUE TO DROP SOUTHEAST CROSSING SOUTHWEST LOWER MICHIGAN
DURING THE EARLY EVENING HOURS. THERE IS A 130 KNOT JET EXIT
REGION THAT CROSSES SOUTHERN LAKE MICHIGAN JUST BEFORE MIDNIGHT
ASSOCIATED WITH FEATURE. THIS JET CORE IS ROTATING AROUND THE BASE
OF THE CLOSED 300 MB LOW THAT IS ALSO ASSOCIATED WITH THIS
FEATURE. BOTH THE NAM12 AND HRRR RUC SUGGEST A MESO-LOW FEATURE
WILL DEVELOP ON THE EAST SIDE (MICHIGAN SIDE)OF THE LAKE AN TRACK
SOUTH THROUGH THE NIGHT ENHANCING THE CONVERGENCE OVER THE LAKE.
GIVEN THE 850 MB TO LAKE TEMP DIFFERENCE IS NEAR 15C. BUFKIT SHOWS
THE EQUILIBRIUM LEVEL OVERNIGHT WILL APPROACH 30000 FT AGL WITH
NEARLY 2000 J/KG OF LAKE INDUCED CAPE. I AM THINKING THIS IS
ENOUGH FOR SCT TO ISOLATED THUNDERSTORMS. LOCALLY HEAVY SHOWERS
SHOULD BE EXPECTED. THAT THINKING IS CONFIRMED BY THE SPC SREF.
NEARLY ALL OF THIS WILL MOSTLY BE OVER LAKE MICHIGAN AND WEST OF
US-131 WHERE THE LAKE INDUCED INSTABILITY WILL BE A FACTOR. INLAND
OF THAT EXPECT PARTLY CLOUDY SKIES WITH POSSIBLY A PASSING SHOWER
AS THE UPPER WAVE MOVE THROUGH.
ONCE THIS FEATURE EXITS THE AREA MID TO LATE MORNING SUNDAY THE
UPPER RIDGE BUILDS IN THROUGH TUESDAY. THERE WILL BE ENOUGH
INSTABILITY YET FOR ISOLATED SHOWERS SOUTH OF ROUTE 10 AND EAST OF
US-131 SUNDAY AFTERNOON SINCE THE UPPER JET WILL NOT BE EAST OF
THERE YET.
SUNDAY NIGHT WITH SURFACE HIGH PRESSURE OVER THE AREA WINDS WILL
BE LIGHT AND SKIES CLEAR. I EXPECT LOWS IN THE MID 30S OVER OUR NE
CWA AND LOWER TO MID 40S ELSEWHERE. A SLOW WARMING TREND FOLLOWS
THEN WITH MOSTLY CLEAR SKIES THROUGH TUESDAY NIGHT.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 305 PM EDT SAT SEP 8 2012
WE/LL START TO WARM UP AGAIN TUESDAY AS THE HIGH MOVES TOWARD NEW
ENGLAND. THE NEXT COLD FRONT WILL LIKELY MOVE ACROSS THE CWA
THURSDAY NIGHT OR FRIDAY. INSTABILITY DOESN/T LOOK VERY IMPRESSIVE
WITH THIS NOR DO THE MOISTURE TRANSPORT VECTORS. AS A RESULT I
CAN/T SEE MUCH MORE THAN SLIGHT CHC POPS AT THIS POINT. THERE IS A
COMPACT SHORT WAVE ASSOCIATED WITH THIS AND THAT MAY BOOST PCPN
CHANCES INTO SATURDAY...BUT GIVEN THE SFC RIDGING MOVING IN AT
THAT POINT...PCPN AMOUNTS AND CHANCES LOOK MEAGER.
TEMPS WILL CLIMB TO AROUND 80 PRIOR TO FROPA AND THAN BACK INTO THE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1213 AM EDT SUN SEP 9 2012
DESPITE SCATTERED RAIN SHOWERS MOVING THROUGH... CONDITIONS ARE
EXPECTED TO REMAIN PREDOMINATELY VFR TONIGHT AND SUNDAY MORNING
WITH CLOUD BASES MOSTLY ABV 4K FT. TSTMS ARE EXPECTED TO REMAIN
MOSTLY OVER LK MI SOUTH OF MKG. SCATTERED CLOUDS ARE EXPECTED
SUNDAY AFTERNOON BEHIND THE FRONT.
&&
.MARINE...
ISSUED AT 633 PM EDT SAT SEP 8 2012
ISSUED ANOTHER SCA FOR THE NRN ZONE. GUSTY WINDS EXPECTED WITH THE
NEXT COLD FRONT CURRENTLY MOVING ACROSS WISCONSIN.
&&
.HYDROLOGY...
ISSUED AT 252 PM EDT SAT SEP 8 2012
RIVERS WILL CONTINUE TO FALL SLOWLY THROUGH THIS COMING WEEK AS
IT IS EXPECTED TO BE DRY MOST OF THIS COMING WEEK. ANY RAINFALL
WE GET TONIGHT WILL ONLY BE NEAR THE LAKE SHORE AND THAT WILL NOT
IMPACT MOST OF RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
LMZ847>849.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ844>846.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...93
AVIATION...MEADE
HYDROLOGY...WDM
MARINE...93
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
309 AM EDT SUN SEP 9 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE OFFSHORE THIS MORNING. STRONG HIGH
PRESSURE WILL BUILD OVER MUCH OF THE EASTERN SEABOARD BY LATE
TODAY AND CONTINUE IN PLACE THROUGH LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 3 AM SUNDAY...THE HEAVY CONVECTIVE ACTIVITY HAS MOVED WELL
OFFSHORE AND WILL REMOVE THUNDER FROM THE FORECAST FOR THE NEXT
UPDATE. PATCHY LIGHT RAIN WILL PERSIST INTO THE MORNING HOURS.
EACH SUCCESSIVE RUN OF THE RAP SHOWS PRECIPITATION ENDING
EARLIER...WITH THE LATEST RUN SHOWING ALL PRECIP OFFSHORE BY 15Z
THIS MORNING. WILL KEEP 40 TO 50 PCT POPS UNTIL ABOUT MIDDAY. EXPECT
IT TO TAKE A BIT LONGER FOR SKIES TO CLEAR AS AXIS OF MUCH LOWER
PRECIPITABLE WATER DOES NOT REACH THE COAST UNTIL ABOUT 21Z...SO
THINK THE MAJORITY OF THE WAY WILL BE ON THE CLOUDY SIDE. THE
CLOUDS...COUPLED WITH DECENT LOW- LEVEL CAA...WILL HOLD MAX
TEMPERATURES IN THE MIDDLE AND UPPER 70S FOR ALL AREAS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
AS OF 305 AM SUNDAY...MUCH DRIER AND COOLER EARLY FALL-LIKE AIR
WILL FILTER INTO THE REGION IN EARNEST TONIGHT. SKIES SHOULD BE
CLEAR BY SUNSET IN ALL AREAS WITH MINIMUM TEMPERATURES TONIGHT IN
THE UPPER 50S INLAND RANGING TO THE LOWER 60S ALONG THE CRYSTAL
COAST AND MIDDLE 60S ALONG THE OUTER BANKS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 3 AM SUN...EXTENDED STRETCH OF NICE WEATHER IN STORE. HIGH
PRESSURE CENTERED IN THE OHIO VALLEY MONDAY WILL SHIFT TO THE MID-
ATLANTIC ON THURSDAY...THEN OFFSHORE NEXT WEEKEND. LIGHT NORTH
FLOW MONDAY WILL VEER TO NORTHEAST BY LATE IN THE WEEK. ECMWF
SHOWING A WEAK UPPER LOW FORMING OFFSHORE BY LATE IN THE
WEEK...BRINGING A SLIGHT CHANCE OF SHOWERS TO THE AREA BY
SATURDAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 305 AM SUNDAY...EXPECT PERIODS OF MVFR/IFR CEILINGS THROUGH
MOST OF THE DAY TODAY WITH SOME PATCHY LIGHT SHOWERS UNTIL ABOUT
MIDDAY. DRIER AND COOLER AIR SHOULD BEGIN TO OVERSPREAD THE AREA
BY TONIGHT WITH VFR CONDITIONS BY SUNSET AND THRU THE OVERNIGHT
HOURS.
LONG TERM /MON THROUGH THU/
AS OF 3 AM SUN...EXTENDED PERIOD OF EXCELLENT FLYING WEATHER WITH
HIGH PRESSURE CENTERED OVER THE REGION. MOSTLY CLEAR SKIES. LIGHT
NORTH WINDS MONDAY AND TUESDAY...VEERING TO NORTHEAST FOR
WEDNESDAY AND THURSDAY.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 310 AM SUNDAY...AS ANTICIPATED...GETTING A BIT OF A SURGE
BEHIND STRONG COLD FRONT WHICH WILL GRADUALLY WORKING ITS WAY
OFFSHORE EARLY THIS MORNING. THINK THE MAXIMUM WINDS IN THE SURGE
WILL HOLD AT 20 KNOTS IN GUSTS. SEAS CONTINUE AT 4 TO 6 FEET WITH
LONG PERIOD (13 SECOND) SWELLS UP AND DOWN THE NC COAST. THIS WILL
LEAD TO ANOTHER DAY OF ELEVATED RIP CURRENT THREAT FOR TODAY.
AS OF 3 AM SUN...LATEST RUN OF THE MAJOR MODELS CONTINUE IN VERY
CLOSE AGREEMENT AND USED AN OVERALL BLEND FOR THE WINDS. BASED ON
LATEST RUNS OF WAVEWATCH AND IN-HOUSE SWAN THE SMALL CRAFT
HEADLINES HAVE BEEN TRIMMED BACK TO END EARLIER...06Z TUESDAY
SOUTH OF OCRACOKE AND 00Z WEDNESDAY NORTH OF OCRACOKE. HIGH
PRESSURE CENTERED IN THE OHIO VALLEY MONDAY WILL SHIFT TO THE MID-
ATLANTIC STATES ON THURSDAY. LIGHT NORTHEAST FLOW MONDAY AND
TUESDAY WILL VEER TO NORTHEAST FOR WEDNESDAY AND THURSDAY. LONG
PERIOD EAST SWELL OF 12-13 SECONDS MONDAY WILL SUBSIDE TO 10
SECONDS BY THURSDAY.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...HSA
AVIATION...CTC/HSA
MARINE...CTC/HSA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
737 AM EDT SUN SEP 9 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL SWING THROUGH THE AREA TODAY. AT
THE SURFACE A TROUGH OF LOW PRESSURE WILL LINGER IN THE AREA.
MONDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL DOMINATE ACROSS THE
REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...UPPER VORTEX MOVING ACROSS NORTHERN INDIANA HOWEVER MUCH
OF THE RAIN ASSOCIATED WITH THIS HAS DIMINISHED OVER THE PAST
COUPLE HOURS. HRRR ACTUALLY DOES NOT REDEVELOP THE PRECIP FAVORING
INSTEAD MORE SHOWERS ALONG THE NORTHEAST LAKESHORE ESPECIALLY
THROUGH THE MORNING...AND SPOTTY SHOWERS THIS AFTERNOON. WILL DROP
THE LIKELY POP WEST THIS MORNING AND LOWER TO 30-40%.
ELSEWHERE...ALONG THE EAST LAKESHORE...RAIN HAS DIMINISHED QUITE A
BIT. STILL THINK THERE IS MORE TO COME BUT WILL DROP CAT POPS BACK
TO LIKELY. WILL ALSO RESTRICT THE MENTION OF THUNDER TO THE EAST
LAKESHORE WITH THE INSTABILITY OFF THE LAKE. NO OTHER CHANGES.
ORIGINAL...WE ARE MOVING INTO THE SEASON FOR LAKE EFFECT RAINS
AS INCREASINGLY FREQUENT SHOTS OF COLD AIR MOVE ACROSS THE WARM
LAKE ERIE WATERS. MODELS SHOW A SHARP UPPER TROF SWINGING THROUGH
THE GREAT LAKES DURING THE DAY WHILE THE WATER VAPOR LOOP SHOWS A
VIGOROUS UPPER VORTEX DROPPING INTO THE BASE OF THE TROF ACROSS
SRN LWR MI. 850MB TEMPS ARE FORECAST TO BE 6 TO 7C CURRENTLY WHICH
YIELDS CAPES OF 1000-1300J/KG WITH RESPECT TO THE LAKE. RADAR
SHOWING SHOWERS AND THUNDERSTORMS DEVELOPING JUST OFF SHORE AND
MOVING ACROSS LAKE COUNTY AND THEN NORTHEAST ACROSS ASHTABULA AND
ERIE COUNTIES. DRIVING FLOW FOR LAKE EFFECT WILL BE CHANGEABLE
TODAY WITH THE SYSTEM MOVING THROUGH HOWEVER WILL CONTINUE WITH
CATEGORICAL POPS EAST OF CLEVELAND FOR THE MORNING AND THEN DROP
BACK TO CHANCE POPS BY EVENING. ELSEWHERE...UPPER LEVEL VORTEX TO
OUR WEST HAS SHOWERS AND THUNDERSTORMS ASSOCIATED WITH IT...NOW
MOVING INTO NERN INDIANA AND SOUTH CENTRAL MI. EXPECT THIS TO
MAINTAIN ITSELF AND MOVE ACROSS THE REGION FROM WEST TO EAST
THROUGH THE MORNING. CURRENTLY HAVE HIGH CHANCE IN THE GRIDS AND
MAY BUMP THAT TO LIKELY AT LEAST FOR THE MORNING.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
WILL NEED TO HANG ONTO LOW CHANCE/SLIGHT CHANCE POPS NORTHEAST
TONIGHT AND MONDAY GIVEN 850MB TEMPS REMAINING 6 TO 8C THROUGH THE
PERIOD. NEGATIVE INFLUENCES WOULD BE DRIER AIR MOVING IN AS WELL
AS BUILDING HIGH PRESSURE. AFTER THAT HOWEVER THE BALANCE OF THE
SHORT TERM WILL HAVE HIGH PRESSURE ACROSS THE REGION WITH SLOWLY
MODERATING TEMPS INTO MID WEEK AS THE HIGH DRIFTS TO OUR EAST.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
LITTLE CHANGE TO THE FORECAST FOR THE END OF THE WEEK. HIGH PRESSURE
THURSDAY AND TEMPS SEASONABLE. THERE ARE STILL HINTS THAT THE
WEEKEND FRONT WILL BE A LITTLE SLOW. HAVE CONTINUED THE PRECIP
CHANCES FROM FRIDAY NIGHT INTO SATURDAY. WITH THE BETTER CHANCES
THAT THE FRONT WILL HAVE PASSED OR BE OVERHEAD SATURDAY...HAVE
SLIGHTLY COOLER TEMPS...LOWER 70S WITH SOME LINGERING SHOWERS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
UPPER TROUGH AXIS ON WATER VAPOR IMAGERY MAKING ITS WAY TO NW OHIO
EARLY THIS MORNING. THE SHOWER ACTIVITY WITH IT HAS DIMINISHED
SOMEWHAT...BUT EXPECT SOME ISOLATED TO SCATTERED SHOWER ACTIVITY
TO POP AGAIN FOR THIS AFTERNOON. BEST CHANCES WILL BE ACROSS THE
CENTRAL AND EAST...WITH THUNDER POSSIBLE ACROSS THE SNOWBELT. VFR
OUTSIDE OF SHOWERS. MVFR WITH PERIODS OF IFR WITHIN THE HEAVIER
SHOWERS. WITH RELATIVELY LOW CHANCES AT A SHOWER AND HENCE NON
VFR WEATHER IMPACTING A TAF SITE OTHER THAN ERIE...HAVE JUST
MENTIONED VCSH. AT ERI TRIED TO PUT IN A TEMPO FOR THE HIGHER
PRECIP CHANCES THERE. DURING THE MORNING WINDS WILL GENERALLY BE
LIGHT WSW. A MORE DEFINITIVE SHIFT CAN BE EXPECTED WITH THE
TROUGHS PASSAGE THIS AFTERNOON. BY LATE IN THE DAY WE WILL HAVE
NORTH WINDS.
.OUTLOOK...VFR.
&&
.MARINE...
HAVE CONTINUED THE SMALL CRAFT ADVISORY INTO THE MORNING HOURS FOR
MOST OF THE LAKE. UP THROUGH THE EARLY MORNING HOURS WINDS AT SBI01
AND 45005 ALONG WITH SOME OF THE LAKESHORE OBS WERE A SOLID 15 TO 20
KNOTS WITH THE BUOY REGISTERING 3 FOOTERS. AFTER A CHOPPY START
WINDS/WAVES ARE EXPECTED TO DIMINISH TODAY. THE DIRECTION MAY WAVER
SOME FROM NW TO MORE WESTERLY AND BACK AGAIN TO NNW BY THIS
AFTERNOON. THIS IS FROM A COUPLE OF TROUGHS TO CROSS THE LAKE TODAY.
CONTEMPLATED ADDING THE MENTION OF A CHANCE OF WATERSPOUTS FOR THIS
MORNING...BUT WITH RECENT WIND OBSERVATIONS IT APPEARS THAT THE
CONVERGENT ZONE WITH THIS TROUGH HAS PUSHED INLAND. HIGH PRESSURE
BUILDS ACROSS THE REGION FOR MONDAY THROUGH THURSDAY. IT BEGINS TO
SHIFT EAST OF THE LAKE WEDNESDAY...SO WILL GET SOUTHWEST FLOW BY
THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
LEZ144>148.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
646 AM EDT SUN SEP 9 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL SWING THROUGH THE AREA TODAY. AT
THE SURFACE A TROUGH OF LOW PRESSURE WILL LINGER IN THE AREA.
MONDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL DOMINATE ACROSS THE
REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...UPPER VORTEX MOVING ACROSS NORTHERN INDIANA HOWEVER MUCH
OF THE RAIN ASSOCIATED WITH THIS HAS DIMINISHED OVER THE PAST
COUPLE HOURS. HRRR ACTUALLY DOES NOT REDEVELOP THE PRECIP FAVORING
INSTEAD MORE SHOWERS ALONG THE NORTHEAST LAKESHORE ESPECIALLY
THROUGH THE MORNING...AND SPOTTY SHOWERS THIS AFTERNOON. WILL DROP
THE LIKELY POP WEST THIS MORNING AND LOWER TO 30-40%.
ELSEWHERE...ALONG THE EAST LAKESHORE...RAIN HAS DIMINISHED QUITE A
BIT. STILL THINK THERE IS MORE TO COME BUT WILL DROP CAT POPS BACK
TO LIKELY. WILL ALSO RESTRICT THE MENTION OF THUNDER TO THE EAST
LAKESHORE WITH THE INSTABILITY OFF THE LAKE. NO OTHER CHANGES.
ORIGINAL...WE ARE MOVING INTO THE SEASON FOR LAKE EFFECT RAINS
AS INCREASINGLY FREQUENT SHOTS OF COLD AIR MOVE ACROSS THE WARM
LAKE ERIE WATERS. MODELS SHOW A SHARP UPPER TROF SWINGING THROUGH
THE GREAT LAKES DURING THE DAY WHILE THE WATER VAPOR LOOP SHOWS A
VIGOROUS UPPER VORTEX DROPPING INTO THE BASE OF THE TROF ACROSS
SRN LWR MI. 850MB TEMPS ARE FORECAST TO BE 6 TO 7C CURRENTLY WHICH
YIELDS CAPES OF 1000-1300J/KG WITH RESPECT TO THE LAKE. RADAR
SHOWING SHOWERS AND THUNDERSTORMS DEVELOPING JUST OFF SHORE AND
MOVING ACROSS LAKE COUNTY AND THEN NORTHEAST ACROSS ASHTABULA AND
ERIE COUNTIES. DRIVING FLOW FOR LAKE EFFECT WILL BE CHANGEABLE
TODAY WITH THE SYSTEM MOVING THROUGH HOWEVER WILL CONTINUE WITH
CATEGORICAL POPS EAST OF CLEVELAND FOR THE MORNING AND THEN DROP
BACK TO CHANCE POPS BY EVENING. ELSEWHERE...UPPER LEVEL VORTEX TO
OUR WEST HAS SHOWERS AND THUNDERSTORMS ASSOCIATED WITH IT...NOW
MOVING INTO NERN INDIANA AND SOUTH CENTRAL MI. EXPECT THIS TO
MAINTAIN ITSELF AND MOVE ACROSS THE REGION FROM WEST TO EAST
THROUGH THE MORNING. CURRENTLY HAVE HIGH CHANCE IN THE GRIDS AND
MAY BUMP THAT TO LIKELY AT LEAST FOR THE MORNING.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
WILL NEED TO HANG ONTO LOW CHANCE/SLIGHT CHANCE POPS NORTHEAST
TONIGHT AND MONDAY GIVEN 850MB TEMPS REMAINING 6 TO 8C THROUGH THE
PERIOD. NEGATIVE INFLUENCES WOULD BE DRIER AIR MOVING IN AS WELL
AS BUILDING HIGH PRESSURE. AFTER THAT HOWEVER THE BALANCE OF THE
SHORT TERM WILL HAVE HIGH PRESSURE ACROSS THE REGION WITH SLOWLY
MODERATING TEMPS INTO MID WEEK AS THE HIGH DRIFTS TO OUR EAST.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
LITTLE CHANGE TO THE FORECAST FOR THE END OF THE WEEK. HIGH PRESSURE
THURSDAY AND TEMPS SEASONABLE. THERE ARE STILL HINTS THAT THE
WEEKEND FRONT WILL BE A LITTLE SLOW. HAVE CONTINUED THE PRECIP
CHANCES FROM FRIDAY NIGHT INTO SATURDAY. WITH THE BETTER CHANCES
THAT THE FRONT WILL HAVE PASSED OR BE OVERHEAD SATURDAY...HAVE
SLIGHTLY COOLER TEMPS...LOWER 70S WITH SOME LINGERING SHOWERS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VERY LITTLE IN THE WAY OF ANY CHANGES TO THE TAFS THIS GO AROUND.
A SERIES OF TROUGHS WILL CROSS THE LOCAL AREA OVER THE NEXT 15
HOURS. CURRENT TROUGH IS PRODUCING MODERATE SHRA BETWEEN CLE AND
ERI. EXPECT A LULL AS WE GET A BRIEF PERIOD OF RIDGING AHEAD OF
THE NEXT TROUGH. THIS NEXT TROUGH WILL ARRIVE DURING THE DAYLIGHT
HOURS AND FOR LOCATIONS ALONG AND EAST A CLE/MFD LINE...WITH HAVE
THE EXTRA BOOST OF THE HEATING OF THE DAY. HAVE MAINTAINED THE
VCSH MENTIONS AND THE TEMPOS EAST FOR THE SOMEWHAT BETTER CHANCES
THERE. THUNDER IS A POSSIBILITY. OUTSIDE OF THE SHOWERS...VFR
WEATHER EXPECTED. MVFR WITH PERIODS OF IFR WITHIN THE HEAVIER
SHOWERS. DURING THE MORNING WINDS WILL GENERALLY BE LIGHT
WSW..WITH SOME BACKING AHEAD OF THE NEXT TROUGH. A MORE DEFINITIVE
SHIFT CAN BE EXPECTED WITH THIS AFTERNOONS TROUGH AND BY LATE IN
THE DAY WE WILL HAVE NORTH WINDS.
.OUTLOOK...VFR.
&&
.MARINE...
HAVE CONTINUED THE SMALL CRAFT ADVISORY INTO THE MORNING HOURS FOR
MOST OF THE LAKE. UP THROUGH THE EARLY MORNING HOURS WINDS AT SBI01
AND 45005 ALONG WITH SOME OF THE LAKESHORE OBS WERE A SOLID 15 TO 20
KNOTS WITH THE BUOY REGISTERING 3 FOOTERS. AFTER A CHOPPY START
WINDS/WAVES ARE EXPECTED TO DIMINISH TODAY. THE DIRECTION MAY WAVER
SOME FROM NW TO MORE WESTERLY AND BACK AGAIN TO NNW BY THIS
AFTERNOON. THIS IS FROM A COUPLE OF TROUGHS TO CROSS THE LAKE TODAY.
CONTEMPLATED ADDING THE MENTION OF A CHANCE OF WATERSPOUTS FOR THIS
MORNING...BUT WITH RECENT WIND OBSERVATIONS IT APPEARS THAT THE
CONVERGENT ZONE WITH THIS TROUGH HAS PUSHED INLAND. HIGH PRESSURE
BUILDS ACROSS THE REGION FOR MONDAY THROUGH THURSDAY. IT BEGINS TO
SHIFT EAST OF THE LAKE WEDNESDAY...SO WILL GET SOUTHWEST FLOW BY
THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
LEZ144>148.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS PORTLAND OR
200 PM PDT SUN SEP 9 2012
.SYNOPSIS...A COLD FRONT FROM THE GULF OF ALASKA WILL PUSH THROUGH
THE REGION LATE TONIGHT AND EARLY MON BRINGING A SHOT OF RAIN TO
MANY AREAS ALONG WITH COOLER AIR. HIGH PRESSURE WILL SLOWLY BUILD
INTO THE REGION TUESDAY AND WEDNESDAY...RESULTING IN RISING
TEMPERATURES AND PLENTY OF SUNSHINE.
&&
.SHORT TERM...CAMERAS AND A FEW OBSERVATIONS SHOW SOME LIGHT RAIN
STILL OCCURRING ALONG THE COAST EARLY THIS AFTERNOON...WITH MARINE
CLOUDS STILL HANGING IN OVER MUCH OF THE FORECAST AREA. WELL
ADVERTISED COLD FRONT IS SEEN ON SATELLITE PICTURES STRETCHING FROM
NEAR THE N END OF VANCOUVER ISLAND SW PAST ABOUT 45N 135W. SATELLITE
DERIVED PRECIPITABLE WATER VALUES ON THE ORDER OF 1.25 INCHES
PRECEDE THE FRONT. WITH RELATIVELY DEEP MOISTURE AND A SHARP
FRONT...EXPECT A PERIOD OF SEVERAL HOURS OF RAIN LIKELY FOR MUCH OF
THE NORTHERN HALF OF THE FORECAST AREA...WITH LOWER POPS TO THE S.
RECENT MODEL RUNS CONTINUE TO SHOW THE MOST LIKELY TIME FOR RAINFALL
TO OCCUR AFTER MIDNIGHT TONIGHT IN THE NW PART OF THE AREA...AND MON
MORNING FURTHER SE. SATLLITE PICTURES SHOW SOME SHOWERS IN THE
COLDER AIR BEHIND THE FRONT...BUT MOST OF THE INSTABILITY IS
EXPECTED TO PASS BY TO THE N. STILL...WILL LEAVE IN SOME LOW POPS
FOR SHOWERS BEHIND THE FRONT LATER IN THE DAY MON.
DRYING OF THE AIR MASS KICKS IN RELATIVELY QUICKLY MON NIGHT AND TUE
AS LOW LEVEL FLOW TURNS MORE NORTHERLY AND UPPER TROUGH PASSES BY TO
THE E. COOL AIR EXPECTED TO LINGER INTO TUE BEFORE WARMING BACK
ABOVE SEASONAL NORMALS WED IN RESPONSE TO THE BUILDING UPPER RIDGE.
.LONG TERM...A STRONG UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE
FORECAST AREA BY EARLY WEDNESDAY...WITH THE AXIS MOVING THROUGH THE
AREA BY EARLY THURSDAY. WITH AN EQUALLY STRONG THERMAL TROUGH
PATTERN DEVELOPING AT THE SURFACE...TEMPERATURES SHOULD BE ALLOWED
TO WARM WELL ABOVE NORMAL EACH DAY OF THE LAST HALF OF THE WEEK
UNDER CLEAR SKIES AND OFFSHORE FLOW. DISCOUNTING THE MOST CURRENT
RUN OF THE ECMWF...WHICH IS QUITE DIFFERENT FROM PREVIOUS RUNS...THE
DRY PATTERN SHOULD CONTINUE INTO NEXT WEEKEND AS THE UPPER LEVEL
RIDGE BEGINS TO WEAKEN AND MOVE EASTWARD. BROWN
&&
.AVIATION...CIGS HAVE LINGERED IN THE LOW VFR CATEGORY TODAY...WITH
MOST LOCATIONS HOVERING IN THE 3500-5000 FT RANGE...THOUGH THERE ARE
POCKETS OF MVFR RETURNING THIS AFTERNOON. EXPECT THIS TO CONTINUE
THROUGH THE EVENING UNTIL THE MAIN FRONTAL FORCING COMES IN. FRONTAL
RAIN IS NOT EXPECTED AT THE S WA/N OR COAST UNTIL ABOUT 5Z OR SO.
THE COAST WILL CONTINUE TO REMAIN IN MVFR CONDITIONS WITH OFF AND ON
LIGHT RAIN/DRIZZLE IN A WEAK ISENTROPIC LIFT REGIME. EXPECT A PERIOD
OF MVFR INLAND LATE TONIGHT INTO EARLY MONDAY WITH THE BEST FRONTAL
FORCING OCCURRING BETWEEN 10-15Z. HIGHEST CONFIDENCE IN THE NORTH
VALLEY.
THE FRONTAL PASSAGE AT ASTORIA SHOULD BE AROUND 9Z OR SO...AROUND
15Z IN THE NORTH INTERIOR...AND SLIGHTLY LATER FURTHER SOUTH DOWN
THE VALLEY. WINDS SHIFT FOLLOWING THE FRONT TO WNW NEAR KPDX...MORE
NNW AS YOU GET FURTHER SOUTH. CONDITIONS RETURN TO VFR WITH
OCCASIONAL MVFR MAINLY FOR COASTAL AREAS BEHIND THE FRONT. KMD
KPDX AND APPROACHES...OVC SKIES WITH CIGS FROM 3500-5000 FT WILL
CONTINUE THROUGH THE EVENING. 70 PERCENT OF MVFR CIGS JUST AHEAD OF
THE COLD FRONT. BEST CHANCE FOR CIGS AND PRECIP WILL BE FROM 10-15Z.
KMD
&&
.MARINE...MODERATE SOUTHERLY WINDS CONTINUE ACROSS THE COASTAL
WATERS AHEAD OF A SHARP SURFACE TROUGH APPROACHING THE COAST. WE
HAVE EVEN SEEN A STEADY PERIOD OF WINDS/GUSTS 22-29 KT TO OUR INNER
NORTHERN WATERS TODAY FROM 15-21Z AS REPORTED BY THE CAPE D AND
CLATSOP SPIT MESONET SITES. FURTHER OFFSHORE BUOY 29 WINDS HAVE FOR
THE MOST PART BEEN 20 KT OR LESS THOUGH THERE HAVE BEEN A FEW GUSTS
INTO THE 20S. GRADIENT LOOKS TO SLACKEN ENOUGH LATER THIS AFTERNOON
OR EARLY EVENING TO BRING WINDS BACK TO AROUND 20 KT FOR THE INNER
WATERS.
BEHIND THE SURFACE TROUGH...A COLD FRONT CURRENTLY IN THE VICINITY
OF WILL BRING A SHARP WIND SHIFT TO NW WINDS MON MORNING. SOME LOW
END SCA GUSTS ARE POSSIBLE IN THE NORTHERN OUTER WATERS AROUND TO
SLIGHTLY AFTER MIDNIGHT INTO EARLY MONDAY AS THERE WILL BE SOME
FAIRLY STRONG COLD ADVECTION...WHICH OFTEN CAUSES WINDS TO
OVER-PERFORM WHAT MODELS SUGGEST. COULD GO EITHER WAY ON THIS
ONE...HI RES HRRR SUPPORTS THE GFS WITH GUSTS AGAIN IN THE MID
20S...SO WILL GO WITH A RELATIVELY SHORT LIVED ADVISORY FOR POINTS
WELL OFFSHORE. NORTHERLY FLOW THEN INCREASES THROUGHOUT THE WATERS
TUE-THU AS STRONG HIGH PRESSURE BUILDS OVER THE NE PACIFIC AND A
THERMAL TROUGH BUILDS UP THE COAST FROM NORTHERN CALIFORNIA. SEAS
WILL LIKELY BECOME QUITE STEEP DURING THIS PERIOD...AND MAY APPROACH
10 FT. KMD
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FOR WATERS FROM CAPE SHOALWATER
WA TO CASCADE HEAD OR OUT 10 NM UNTIL 5 PM PDT.
SMALL CRAFT ADVISORY FOR WINDS FOR WATERS FROM CAPE SHOALWATER
WA TO CASCADE HEAD OR FROM 10 TO 60 NM FROM 9 PM TO 5 AM PDT.
&&
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1027 PM CDT MON SEP 10 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
SHIFTING EAST OVER THE CENTRAL GREAT LAKES WHILE LOW PRESSURE IS
LOCATED OVER THE NORTHERN GREAT PLAINS. EXCEPT FOR CIRRUS FLOATING
OVER NORTH DAKOTA AND NORTHERN MINNESOTA...CLEAR SKIES EXIST ACROSS
MUCH OF THE MISSISSIPPI VALLEY AND THE GREAT PLAINS...OWING TO THE
VERY DRY AIRMASS AHEAD OF THE LOW PRESSURE. GUSTS AHEAD OF THE LOW
PRESSURE ARE ALSO REACHING INTO THE UPPER 20S TO LOWER 30S KTS WHICH
WILL BE SHIFTING INTO OUR AREA TOMORROW. WITH LITTLE THREAT OF
PRECIP...TEMPS AND WIND GUSTS ARE THE MAIN FORECASTS CONCERNS.
TONIGHT...HIGH PRESSURE WILL SHIFT TO THE APPALACHIANS WHILE LOW
PRESSURE MOVES ACROSS THE DAKOTAS. AHEAD OF THE LOW PRESSURE...THE
PRESSURE GRADIENT INCREASES SUBSTANTIALLY TONIGHT AND PRODUCES A LOW
LEVEL JET OF 40+ KNOTS ABOUT 1000 FT OFF THE SURFACE. THIS SHOULD
KEEP THE BOUNDARY LAYER CHURNED UP ESPECIALLY OVER HIGHER TERRAIN
AND PREVENT TEMPS FROM FALLING NEARLY AS COLD AS THE PAST COUPLE
NIGHTS. WILL GO WITH LOWS MAINLY IN THE 50S. OTHER THAN CIRRUS
DRIFTING OVERHEAD...SKIES WILL BE CLEAR.
TUESDAY...LOW PRESSURE WILL MOVE ACROSS MINNESOTA AND INTO FAR
NORTHWEST WISCONSIN BY 00Z WEDNESDAY. THE AIRMASS AHEAD OF THE
FRONT IS VERY DRY WITH DEWPOINTS IN THE 40S AND 50S...SO NO THREAT
OF ANY PRECIP AHEAD OF THE FRONT. THE TIGHT PRESSURE GRADIENT WILL
STILL BE THERE AND MIXING UP TO AROUND 900MB SHOULD BE ABLE TO
PRODUCE GUSTS 30 TO 35 MPH IN THE AFTERNOON. SW WINDS WILL CONTINUE
TO DRAW WARMER AIR INTO THE REGION FROM THE GREAT PLAINS AS 850MB
TEMPS INCREASE TO AROUND 20C. WILL NOT BE ABLE TO TAP INTO THIS AIR
THOUGH...SO THE SHALLOW MIXING WILL ONLY PLACE HIGHS INTO THE LOW TO
MID 80S.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...MAIN FCST CONCERN
IS PCPN TRENDS THROUGH THE PERIOD...AND A BIG CHANGE IN TEMPERATURES
FROM WEDNESDAY INTO THURSDAY.
A COLD FRONT WILL ENTER NC WI ON TUESDAY NIGHT...BUT WITH AN INITIALLY
DRY AIR MASS AND UPPER FORCING LAGGING TO THE WEST OF THE FRONT...WILL
MAINTAIN THE DRY FCST. THE FRONT WILL SAG SE ACROSS THE FORECAST AREA
ON WEDS AND WEDS NGT...WITH POST-FRONTAL PCPN DEVELOPING DUE THE
INCOMING UPPER TROF...THE RRQ OF A STRG JET STREAK AND MID-LEVEL
FRONTOGENETIC FORCING. ECMWF/GFS/GEM/UKMET ALL SHOW SIMILAR TIMING...
WHICH WAS A BIT FASTER THAN OUR PREVIOUS FCST...AND PERHAPS 6 HOURS
FASTER THAN THE 12Z NAM. HOWEVER...GIVEN RECENT MODEL DIFFERENCES AND
A NEED TO MESH WITH FCSTS FROM SURROUNDING OFFICES...OPTED TO
CONTINUE WITH A BLENDED APPROACH FOR POPS. REGARDLESS...THE HIGHEST
POPS REMAIN CENTERED AROUND WEDS NGT AND THURSDAY. SUBSEQUENT FCSTS
MAY NEED TO BE A BIT MORE AGGRESSIVE ENDING THE PCPN OVER OUR NW
COUNTIES ON THU/THU NGT.
SECOND PROBLEM WITH POPS OCCURS FRIDAY INTO SATURDAY...AS THE GFS
SHIFTS THE UPPER TROF AND FRONT FAR ENOUGH EAST TO END THE PCPN OVER
WI...WHILE THE ECMWF CLOSES OFF A STG UPPER LOW OVER THE RGN...INDUCES
SFC CYCLOGENESIS...REGENERATES PCPN OVER MUCH OF WI...AND LINGERS
IT WELL INTO THE WEEKEND. THE ECMWF SEEMS OVERDONE COMPARED TO
THE ENSEMBLES...BUT IT SHOULD BE NOTED THAT IT HAS SHOWN AN UPPER
LOW IN THE WSTRN GREAT LKS/UPPER MIDWEST LATE IN THE WEEK FOR THE
PAST 5 MODEL RUNS. ONCE AGAIN...HAVE OPTED FOR THE PREFERRED MODEL
BLEND...BUT BIG CHANGES WILL BE NEEDED LATER IN THE WEEK IF THE
ECMWF SOLN LOOKS LIKE IT WILL VERIFY.
MUCH ABOVE NORMAL TEMPERATURES (LOW TO MID 80S) IN ADVANCE OF THE
FRONT WILL BE REPLACED BY SLIGHTLY COOLER THAN NORMAL 60S FOR THE
END OF THE WEEK. WEEKEND TEMPS ARE UP IN THE AIR DUE TO THE
PREVIOUSLY-MENTIONED MODEL DIFFERENCES.
&&
.AVIATION...MPX SOUNDING THIS EVENING SHOWS A 30 TO 35KT LOW LEVEL
JET TO 2K FEET. LOW LEVEL WIND SHEAR WILL CONTINUE BEFORE WINDS
MIX DOWN LATER TUESDAY MORNING TO PRODUCE INCREASING WIND GUSTS
OUT OF THE SOUTHWEST. SOME GUSTS UP TO 30 KTS WILL BE POSSIBLE
TUESDAY AFTERNOON. OTHERWISE VFR CONDITIONS TO PREVAIL TONIGHT
INTO TUESDAY.
TDH
&&
.MARINE...PERSISTENT AND STRENGTHENING SOUTH TO SOUTHWEST FLOW
WILL LEAD TO HAZARDOUS CONDITIONS FOR SMALL CRAFT TONIGHT THROUGH
WEDNESDAY. SMALL CRAFT ADVISORIES ARE ALREADY IN EFFECT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
628 PM CDT MON SEP 10 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
SHIFTING EAST OVER THE CENTRAL GREAT LAKES WHILE LOW PRESSURE IS
LOCATED OVER THE NORTHERN GREAT PLAINS. EXCEPT FOR CIRRUS FLOATING
OVER NORTH DAKOTA AND NORTHERN MINNESOTA...CLEAR SKIES EXIST ACROSS
MUCH OF THE MISSISSIPPI VALLEY AND THE GREAT PLAINS...OWING TO THE
VERY DRY AIRMASS AHEAD OF THE LOW PRESSURE. GUSTS AHEAD OF THE LOW
PRESSURE ARE ALSO REACHING INTO THE UPPER 20S TO LOWER 30S KTS WHICH
WILL BE SHIFTING INTO OUR AREA TOMORROW. WITH LITTLE THREAT OF
PRECIP...TEMPS AND WIND GUSTS ARE THE MAIN FORECASTS CONCERNS.
TONIGHT...HIGH PRESSURE WILL SHIFT TO THE APPALACHIANS WHILE LOW
PRESSURE MOVES ACROSS THE DAKOTAS. AHEAD OF THE LOW PRESSURE...THE
PRESSURE GRADIENT INCREASES SUBSTANTIALLY TONIGHT AND PRODUCES A LOW
LEVEL JET OF 40+ KNOTS ABOUT 1000 FT OFF THE SURFACE. THIS SHOULD
KEEP THE BOUNDARY LAYER CHURNED UP ESPECIALLY OVER HIGHER TERRAIN
AND PREVENT TEMPS FROM FALLING NEARLY AS COLD AS THE PAST COUPLE
NIGHTS. WILL GO WITH LOWS MAINLY IN THE 50S. OTHER THAN CIRRUS
DRIFTING OVERHEAD...SKIES WILL BE CLEAR.
TUESDAY...LOW PRESSURE WILL MOVE ACROSS MINNESOTA AND INTO FAR
NORTHWEST WISCONSIN BY 00Z WEDNESDAY. THE AIRMASS AHEAD OF THE
FRONT IS VERY DRY WITH DEWPOINTS IN THE 40S AND 50S...SO NO THREAT
OF ANY PRECIP AHEAD OF THE FRONT. THE TIGHT PRESSURE GRADIENT WILL
STILL BE THERE AND MIXING UP TO AROUND 900MB SHOULD BE ABLE TO
PRODUCE GUSTS 30 TO 35 MPH IN THE AFTERNOON. SW WINDS WILL CONTINUE
TO DRAW WARMER AIR INTO THE REGION FROM THE GREAT PLAINS AS 850MB
TEMPS INCREASE TO AROUND 20C. WILL NOT BE ABLE TO TAP INTO THIS AIR
THOUGH...SO THE SHALLOW MIXING WILL ONLY PLACE HIGHS INTO THE LOW TO
MID 80S.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...MAIN FCST CONCERN
IS PCPN TRENDS THROUGH THE PERIOD...AND A BIG CHANGE IN TEMPERATURES
FROM WEDNESDAY INTO THURSDAY.
A COLD FRONT WILL ENTER NC WI ON TUESDAY NIGHT...BUT WITH AN INITIALLY
DRY AIR MASS AND UPPER FORCING LAGGING TO THE WEST OF THE FRONT...WILL
MAINTAIN THE DRY FCST. THE FRONT WILL SAG SE ACROSS THE FORECAST AREA
ON WEDS AND WEDS NGT...WITH POST-FRONTAL PCPN DEVELOPING DUE THE
INCOMING UPPER TROF...THE RRQ OF A STRG JET STREAK AND MID-LEVEL
FRONTOGENETIC FORCING. ECMWF/GFS/GEM/UKMET ALL SHOW SIMILAR TIMING...
WHICH WAS A BIT FASTER THAN OUR PREVIOUS FCST...AND PERHAPS 6 HOURS
FASTER THAN THE 12Z NAM. HOWEVER...GIVEN RECENT MODEL DIFFERENCES AND
A NEED TO MESH WITH FCSTS FROM SURROUNDING OFFICES...OPTED TO
CONTINUE WITH A BLENDED APPROACH FOR POPS. REGARDLESS...THE HIGHEST
POPS REMAIN CENTERED AROUND WEDS NGT AND THURSDAY. SUBSEQUENT FCSTS
MAY NEED TO BE A BIT MORE AGGRESSIVE ENDING THE PCPN OVER OUR NW
COUNTIES ON THU/THU NGT.
SECOND PROBLEM WITH POPS OCCURS FRIDAY INTO SATURDAY...AS THE GFS
SHIFTS THE UPPER TROF AND FRONT FAR ENOUGH EAST TO END THE PCPN OVER
WI...WHILE THE ECMWF CLOSES OFF A STG UPPER LOW OVER THE RGN...INDUCES
SFC CYCLOGENESIS...REGENERATES PCPN OVER MUCH OF WI...AND LINGERS
IT WELL INTO THE WEEKEND. THE ECMWF SEEMS OVERDONE COMPARED TO
THE ENSEMBLES...BUT IT SHOULD BE NOTED THAT IT HAS SHOWN AN UPPER
LOW IN THE WSTRN GREAT LKS/UPPER MIDWEST LATE IN THE WEEK FOR THE
PAST 5 MODEL RUNS. ONCE AGAIN...HAVE OPTED FOR THE PREFERRED MODEL
BLEND...BUT BIG CHANGES WILL BE NEEDED LATER IN THE WEEK IF THE
ECMWF SOLN LOOKS LIKE IT WILL VERIFY.
MUCH ABOVE NORMAL TEMPERATURES (LOW TO MID 80S) IN ADVANCE OF THE
FRONT WILL BE REPLACED BY SLIGHTLY COOLER THAN NORMAL 60S FOR THE
END OF THE WEEK. WEEKEND TEMPS ARE UP IN THE AIR DUE TO THE
PREVIOUSLY-MENTIONED MODEL DIFFERENCES.
&&
.AVIATION...VFR CONDITIONS TO CONTINUE TONIGHT INTO TUESDAY.
HOWEVER OF AVIATION CONCERN WILL BE THE LOW LEVEL WIND SHEAR
TONIGHT AS A LOW LEVEL JET INCREASES TO AROUND 40 KNOTS AT 800 FT
AGL WITH SFC WINDS OF 5 TO 10 KTS. ONCE TEMPERATURES WARM TUESDAY
MORNING...WIND GUSTS OUT OF THE SOUTHWEST WILL INCREASE GREATER
THAN 20 KTS. SOME GUSTS UP TO 30 KTS WILL BE POSSIBLE TUESDAY
AFTERNOON.
TDH
&&
.MARINE...PERSISTENT AND STRENGTHENING SOUTH TO SOUTHWEST FLOW
WILL LEAD TO HAZARDOUS CONDITIONS FOR SMALL CRAFT TONIGHT THROUGH
WEDNESDAY. SMALL CRAFT ADVISORIES ARE ALREADY IN EFFECT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT SUN SEP 9 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
340 PM CDT SUN SEP 9 2012
AT 3 PM...A 1021 MB SURFACE HIGH WAS CENTERED OVER SOUTH-CENTRAL
MINNESOTA AND NORTH-CENTRAL IOWA. MEANWHILE ALOFT...A SHORT WAVE
TROUGH MOVING SOUTHEAST ACROSS WISCONSIN. THE COMBINATION OF COLD
AIR ALOFT AND 850 TO 750 MB MOISTURE HAS RESULTED IN A SCATTERED
TO BROKEN DECK OF OPEN CELLULAR CLOUDS ACROSS SOUTHERN AND EASTERN
WISCONSIN.
WITH THE LOSS OF DIURNAL HEATING LATE THIS AFTERNOON AND EARLY
EVENING AND SUBSIDENCE IN THE WAKE OF THIS WAVE...THESE CLOUDS
WILL QUICKLY DISSIPATE. THE SURFACE HIGH WILL DRIFT SOUTHEAST
ACROSS EASTERN IOWA AND CENTRAL ILLINOIS TONIGHT. THE BUFKIT
SOUNDINGS CONTINUE TO SHOW THAT THERE WILL BE A DEEP LAYER /UP TO
800 MB/ OF LIGHT WINDS /5 KNOTS OR LESS/ THROUGH 09.06Z...AND THEN
THE WINDS JUST ABOVE THE SURFACE WILL QUICKLY CLIMB INTO THE 10 TO
15 KNOT RANGE AS THE HIGH PULLS AWAY FROM THE AREA. THIS WILL
GREATLY LIMIT THE DEPTH OF THE BOUNDARY LAYER. IN ADDITION...THE
DRY DEW POINTS /IN THE MID AND UPPER 40S/ WILL SLOW THE SATURATION
OF THE BOUNDARY LAYER. DUE TO THE WINDS LATE TONIGHT AND DRY DEW
POINTS...CHANGED THE FORECAST TO SAY PATCHY FOG INSTEAD OF AREAS
OF FOG IN MOST LOCATIONS. THE ONE EXCEPTION MAY BE IN THE
WISCONSIN RIVER VALLEY WHERE ITS DEPTH AND STEEPNESS MAY AID IN A
DEEPER BOUNDARY LAYER.
ON MONDAY AND TUESDAY...THERE WILL BE A STRENGTHENING SURFACE
PRESSURE GRADIENT AS THE HIGH MOVES EAST OF THE AREA AND A COLD
FRONT MOVES SLOWLY EAST ACROSS THE DAKOTAS...AND WESTERN AND
NORTHERN MINNESOTA. THE SOUTH WINDS WILL RANGE FROM 15 TO 25 MPH
ON BOTH AFTERNOONS. 850 MB TEMPERATURES WILL BE ABOUT 9C WARMER
/AROUND 16C/ ON MONDAY AFTERNOON AND ANOTHER 4C RISE /AROUND 20C/
ON TUESDAY AFTERNOON. THESE TEMPERATURES ARE AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL FOR TUESDAY. THIS WILL RESULT IN HIGH
TEMPERATURES AROUND 90 DEGREES MAINLY NORTHWEST OF A CHARLES CITY
IOWA TO BLACK RIVER FALLS LINE. RECORD HIGH TEMPERATURES FOR THIS
DATE ARE IN THE MID 90S.
ON WEDNESDAY...THE MODELS CONTINUE TO SLOW THE EASTWARD PROGRESS
OF THE SURFACE COLD FRONT. WITH VERY AIR LOCATED ALOFT AHEAD OF
THIS FRONT...THE PRECIPITATION IS MAINLY ANABATIC. DUE TO THIS...
THE PRECIPITATION WAS LOWERED ACROSS NORTHERN WISCONSIN AND
SOUTHEAST MINNESOTA...AND REMOVED FOR THE REMAINDER OF THE AREA.
IN ADDITION...HIGH TEMPERATURES WERE RAISED SOME IN THE
ANTICIPATION OF MORE SUNSHINE AND LESS CLOUD COVER.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
340 PM CDT SUN SEP 9 2012
FROM WEDNESDAY NIGHT THROUGH FRIDAY...MANY OF 09.12Z MODELS SHOW
THAT A COLD FRONT WILL MOVE SLOWLY SOUTHEAST THROUGH THE MID AND
UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES. THE COMBINATION OF
MODERATE TO STRONG FRONTOGENESIS AND THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET WILL ENHANCE THE LIFT IN THE WAKE OF THE FRONT.
IN ADDITION BOTH THE GEM AND ECMWF DEVELOP A LOW PRESSURE SYSTEM
OVER THE REGION ON FRIDAY. IF THIS OCCURS...THE PRECIPITATION
COULD LINGER INTO FRIDAY NIGHT. CONSALL TEMPERATURE AND PRECIPITATION
GRIDS LOOKED MUCH BETTER THAN THE ALL BLEND FOR WEDNESDAY NIGHT
AND THURSDAY...SO WENT WITH THEM INSTEAD. WITH THIS SAID...MAY NOT
BE HIGH ENOUGH YET WITH THE PRECIPITATION CHANCES AND COLD ENOUGH
WITH THE DAYTIME TEMPERATURES. IF THE GEM AND ECMWF ARE CORRECT
MAY HAVE TO ALSO RAISE THE PRECIPITATION CHANCES FOR THURSDAY
NIGHT INTO FRIDAY NIGHT.
&&
.AVIATION...
600 PM CDT SUN SEP 9 2012
RIVER VALLEY FOG AT KLSE IS THE MAIN AVIATION CONCERN WITH HIGH
PRESSURE OVERHEAD RESULTING IN A FAVORABLE SCENARIO. WINDS WILL
DECOUPLE QUICKLY WITH SUNDOWN...WITH LIGHT SFC WINDS THROUGH THE
NIGHT. MODELS CONTINUE TO POINT TO AN INCREASE IN WINDS ABOVE THE
INVERSION BY 09Z...A CONSISTENT SIGNAL OVER THE PAST COUPLE DAYS.
NOT CONVINCED THIS IS SUPPORTED BY THE SYNOPTIC SETUP. EVEN IF THESE
STRONGER WINDS ARE REALIZED...THE INVERSION SHOULD BE WELL IN PLACE
WHERE THERE WOULD BE LITTLE IMPACT ON THE FG POTENTIAL. MEANWHILE
TDS DID NOT DROP OFF AS MUCH AS PREVIOUSLY THOUGHT. BUFKIT RAP IS
WOEFULLY TOO HIGH WHILE THE NAM12 IS TOO DRY. THE NAM12 STAYS DRY
ALL NIGHT...WITH NO EVENING REBOUND. BELIEVE THIS IS IN CORRECT.
WILL OPT TO STAY WITH BCFG AT KLSE FOR THE MOMENT...BUT WILL
CONTINUE TO MONITOR OBS CLOSELY. IF THE TD CLIMBS 5-7 DEGREES THIS
EVENING...THE 1/4SM FG RISK CLIMBS ALSO.
THE HIGH SHIFTS EAST ON MONDAY...WITH A TIGHT PRESSURE GRADIENT
RESULTING IN A BREEZY SOUTHERLY FLOW. SOME AFTERNOON MIXING SHOULD
RESULT IN GUSTS UP TO 30 MPH AT KRST.
&&
.CLIMATE...TUESDAY
340 PM CDT SUN SEP 9 2012
HIGH TEMPERATURES WILL CLIMB TO AROUND 90 DEGREES MAINLY NORTHWEST
OF A CHARLES CITY IOWA TO BLACK RIVER FALLS LINE ON TUESDAY. THE
RECORD HIGHS FOR THIS DATE ARE...
LA CROSSE WI - 97 IN 1897
MEDFORD WI - 95 IN 1900
ROCHESTER MN - 94 IN 1931
AUSTIN MN - 92 IN 1948
CHARLES CITY IA - 96 IN 2000
DECORAH IA - 97 IN 1895
&&
.FIRE WEATHER...MONDAY AND TUESDAY
340 PM CDT SUN SEP 9 2012
WITH THE STRONG WARMING AND INCREASING GRADIENT WINDS MON/TUE...
POTENTIAL EXISTS FOR SOME CRITICAL FIRE WEATHER CONDITIONS BOTH
MONDAY AND TUESDAY AFTERNOONS. HOW CRITICAL WILL DEPEND ON DIURNAL
MIXING AND IF DEW POINTS DROP. FOR NOW MINIMUM AFTERNOON
HUMIDITIES BOTH DAYS LOOK TO RANGE FROM THE MID 20S TO AROUND 30.
HOWEVER THESE HUMIDITIES WILL BE COMBINED WITH THE DRYING
LANDSCAPE/MATURING VEGETATION...AND SOUTH TO SOUTHWEST WINDS IN
THE 15-25 MPH GUSTS OF AROUND 30 MPH. ESPECIALLY CONCERNED ABOUT
THE LONG GRASSES AND POTENTIAL FOR FIELD FIRES AS SOME FARMERS MAY
TRY TO HARVEST SOME FIELDS. FIRE WEATHER USER GROUPS WERE NOT THAT
CONCERNED SO HELD OFF ISSUING A FIRE WEATHER WATCH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
340 PM CDT SUN SEP 9 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....BOYNE
LONG TERM......BOYNE
AVIATION.......RIECK
CLIMATE........BOYNE
FIRE WEATHER...BOYNE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
253 PM CDT SUN SEP 9 2012
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LARGE HIGH
PRESSURE SYSTEM STRETCHING ACROSS THE GREAT PLAINS...AND MOVING EAST
INTO THE WESTERN GREAT LAKES. MORNING LOW STRATUS BURNED OFF INTO A
CU FIELD WITH HELP FROM MOISTURE FLUXES ADVECTING OFF LAKE
SUPERIOR. A FEW SHOWERS EVEN POPPED UP OVER THE U.P...BUT DIDNT
HAVE ENOUGH TO MAKE IT INTO IRON MOUNTAIN OR WASHINGTON ISLAND EARLY
THIS AFTERNOON. AS A STRONG CANADIAN SURFACE MOVES ACROSS THE
AREA...TEMPS AND CLOUD COVER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...HIGH PRESSURE WILL BE OVER THE STATE DURING THE EVENING
THEN DRIFT TOWARDS THE CENTRAL GREAT LAKES OVERNIGHT. WITH RIDGING
THROUGH THE COLUMN...MAY SEE SCT COVERAGE OF LINGERING CU OVER DOOR
COUNTY DURING EARLY EVENING...BUT SUBSIDENCE SHOULD WIN OUT FAIRLY
QUICKLY WHICH WILL LEAVE CLEAR CONDITIONS THEREAFTER. PWATS WILL
FALL BELOW 0.5 INCHES OVERNIGHT AND WINDS WILL BE CALM...AND THAT
WILL LEAD TO GOOD RADIATIONAL COOLING CONDITIONS. BIAS CORRECTED
GUIDANCE DROPS LOWS INTO THE MID TO UPPER 30S OVER LINCOLN AND
NORTHERN VILAS COUNTY...AND WILL MENTION PATCHY FROST IN THE
FORECAST. LOWS IN THE 40S OUTSIDE OF THE COLD SPOTS.
MONDAY...HIGH PRESSURE WILL BE MOVING TO THE EASTERN GREAT LAKES ON
MONDAY AND WILL START OUT THE DAY WEST OF THE 850MB RIDGE AXIS. AS
A RESULT...WINDS WILL SHIFT TO THE SOUTHWEST AND WILL SEE A WARMING
TREND COMMENCE. THE AIRMASS ADVECTING INTO THE REGION FROM THE
GREAT PLAINS IS VERY DRY...SO EXPECT A SEASONABLE AND MOSTLY SUNNY
DAY WITH HIGHS IN THE LOW TO MID 70S.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...PRECIPITATION TRENDS
FOR THE MID TO LATE PART OF THE UPCOMING WEEK...AND TEMPERATURES...
ARE THE MAIN FCST CONCERNS.
STRONG RETURN FLOW WILL BE ONGOING AT THE BEGINNING OF THE PERIOD...
AHEAD OF AN APPROACHING COLD FRONT. MIN TEMPS WILL BE MILDER ON
MONDAY NIGHT...MAINLY IN THE 50S. MIXING THROUGH 900-875 MB ON
TUESDAY SHOULD YIELD MAX TEMPS IN THE 80-85 RANGE...WARMEST IN THE
SANDY SOIL REGION OF CENTRAL WI. BREEZY CONDITIONS ARE EXPECTED...
WITH SW WINDS GUSTING OVER 25 MPH. THE COMBINATION OF WARM TEMPS...
GUSTY WINDS AND FAIRLY LOW RELATIVE HUMIDITY (30-35 PERCENT) WILL
RESULT IN ELEVATED FIRE DANGER...BUT CONDITIONS DO NOT WARRANT
ANY HEADLINE CONSIDERATIONS.
THE PREVIOUSLY-MENTIONED COLD FRONT IS EXPECTED TO MOVE INTO FAR
NC WI LATE TUESDAY NIGHT. WITH AN INITIAL LACK OF MOISTURE AND
THE UPPER LEVEL FORCING LAGGING TO THE WEST...WILL KEEP THE DRY
FCST INTACT. MUCH ABOVE NORMAL TEMPERATURES ARE ANTICIPATED...
WITH READINGS IN THE 60-65 RANGE.
THE COLD FRONT IS EXPECTED TO SHIFT TOWARD THE FOX VALLEY/LKSHR
AREAS ON WEDS...WITH POST-FRONTAL SHOWERS DEVELOPING NW OF AN
MFI-IMT LINE. SUNSHINE AND COMPRESSIONAL HEATING AHEAD OF THE
FRONT SHOULD STILL ALLOW TEMPS TO REACH THE LOWER TO MIDDLE 80S
OVER PARTS OF C/NE/EC WI...SO HAVE RAISED MAX TEMPS SEVERAL
DEGREES.
HAVE INCREASED POPS FOR THE WEDS NGT/THU PERIOD...AS POST-
FRONTAL PCPN INCREASES DUE TO AN APPROACHING UPPER TROF...UPPER
DIVG IN THE RRQ OF A STRONG JET STREAK...AND MID-LEVEL
FRONTOGENETIC FORCING. PCPN CHANCES BECOME LESS CLEAR DURING
THE THU NGT-FRI NGT PERIOD...AS THE GFS/GEFS SHOVE THE FRONTAL
SYSTEM AND ASSOC PCPN BAND TO OUR EAST...WHILE THE ECMWF STALLS
THE FRONT AND LIFTS A SFC WAVE NORTHWARD ALONG THE BOUNDARY...
RESULTING IN A RENEWED SWATH OF RAIN ACROSS THE AREA LATE
THURSDAY NIGHT INTO FRIDAY NIGHT. DUE TO THE UNCERTAINTY...
HAVE KEPT THE TYPICAL MODEL BLEND FOR NOW...WHICH SIDES TOWARD
THE DRIER SIDE OF THE SOLUTIONS.
ANOTHER WEAK COLD FRONT IS EXPECTED OVER THE WEEKEND...BUT IS
NOT EXPECTED TO BE A BIG WEATHER MAKER.
AFTER WEDNESDAY...THE INCOMING CANADIAN AIR MASS WILL BRING
TEMPERATURES BACK CLOSER TO NORMAL FOR THE MIDDLE OF SEPTEMBER.
&&
.AVIATION...SCATTERED AFTERNOON CLOUDS MAY BE BROKEN FOR A PERIOD OF
TIME EARLY TO MID AFTERNOON BEFORE CLOUDS GRADUALLY DISSIPATE BY
EARLY THIS EVENING. CLEAR SKIES THEREAFTER...THOUGH LIGHT WINDS
WILL ALLOW PATCHY GROUND FOG TO FORM LATE TONIGHT. VFR CONDITIONS
TOMORROW ONCE THE GROUND FOG BURNS OFF.
MPC
&&
.MARINE...PERSISTENT AND STRENGTHENING SOUTH TO SOUTHWEST FLOW
WILL LEAD TO HAZARDOUS CONDITIONS FOR SMALL CRAFT FROM MONDAY
NIGHT THROUGH WEDNESDAY. WILL BE ISSUING SMALL CRAFT ADVISORIES
WITH THIS FCST PACKAGE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TSK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1145 AM CDT SUN SEP 9 2012
.UPDATE...NORTHWEST TO NORTH LOW-LEVEL FLOW WILL KEEP LAKE-EFFECT
RAIN SHOWERS OUT OVER LAKE MICHIGAN THIS AFTERNOON. OTHERWISE
DAYTIME HEATING AND EVAPORATION OF GROUND MOISTURE LEFT OVER FROM
SATURDAY/S RAIN WILL ALLOW FOR SCATTERED CLOUDS THIS AFTERNOON.
.AVIATION/18Z TAFS/...VFR CONDS SUNDAY AFTERNOON AND TONIGHT.
SCATTERED AFTERNOON CUMULUS CLOUDS WITH BASES OF 1000 TO 2500 FEET
RISING TO 4000 TO 5000 FT AS MIXING DEPTH INCREASES WITH HEATING.
NORTHWEST TO NORTH SURFACE WINDS AT 5 TO 10 KNOTS WILL BECOME LIGHT
AND VARIABLE TONIGHT AS SURFACE HIGH PRESSURE RIDGE MOVES ACROSS.
FOG A POSSIBILITY TONIGHT IN RIVER VALLEYS AND LOW SPOTS. WISCONSIN
RIVER VALLEY WILL PROBABLY DROP TO USUAL IFR CONDS WHICH IS NORMAL
FOR THIS TIME OF YEAR WITH HIGH PRESSURE OVERHEAD AND LEFTOVER
MOISTURE IN BOUNDARY LAYER. ON MONDAY...HIGH PRESSURE MOVES EAST AND
SOUTH TO SOUTHWEST LOW LEVEL FLOW DEVELOPS...ON ORDER OF 8 TO 13
KNOTS AT SURFACE WITH 20-25 KNOTS AT 5000 FT AGL IN AFTERNOON.
REMAINDER OF PREVIOUSLY ISSUED DISCUSSION FOLLOWS...
.TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
SCATTERED SHOWERS DEVELOPING IN REGION OF LAND BREEZE CONVERGENCE
OVER MID-LAKE IN WAKE OF DEPARTING SHORT WAVE. FORECAST SOUNDINGS
SHOW FAVORABLE DELTA T AND NORTH-NORTHEAST FLOW DEVELOPING BELOW 5K
FT...WITH NAM...GFS AND RUC 1000-900MB LAYER WIND/CONVERGENCE
FORECASTS INDICATING POTENTIAL OF SHOWERS BRUSHING THE SHORE BETWEEN
12Z AND 18Z. WILL KEEP SOME POPS ALONG THE SHORE FROM MILWAUKEE
SOUTH.
OTHERWISE DRY TROUGH THE PERIOD WITH UPPER RIDGING AND SURFACE HIGH
PRESSURE BUILDING OVER THE REGION...WITH COOL TEMPERATURES. 925MB
TEMPERATURES SUPPORT DAYTIME HIGHS IN THE LOW TO MID 70S WEST TO
AROUND 70 EAST. GOOD RADIATIONAL CONDITIONS TONIGHT WILL ALLOW LOWS
TO FALL INTO THE MID 40S AWAY FROM THE LAKE.
MONDAY THROUGH WEDNESDAY - CONFIDENCE...MEDIUM
BROAD 500 MILLIBAR ANTICYCLONIC FLOW ACROSS THE CWA THIS PERIOD.
SURFACE/850 HIGHS TO THE EAST. A WARMER SOUTHERLY REGIME KICKS IN.
500 MILLIBAR FLOW BECOMES MORE SOUTHWEST ON WEDNESDAY THOUGH BEST
FORCING...BOTH ALOFT AND IN THE LOW LEVELS...REMAINS TO THE NORTH
AND NORTHWEST OF THE CWA. 925 TEMPS SLOW TO RESPOND MONDAY...BUT A
SLIGHT WARMING NOTED. A MORE PRONOUNCED WARMING ON TUESDAY WITH 925
TEMPS BACK TO THE LOW 20S CELSIUS...WITH POSSIBLE MID 20S WEDNESDAY
WITH SOUTHWEST WINDS MAINTAINING THE WARM AIRMASS AHEAD OF THE
FRONT. SO TEMPS WELL INTO THE
WEDNESDAY NIGHT AND THURSDAY - CONFIDENCE...LOW
SURFACE BOUNDARY AND 850 BAROCLINIC ZONE SAGS INTO SRN WI THIS
PERIOD WITH PRECIP CHANCES INCREASING. 500 MILLIBAR FLOW BECOMES
SOUTHWEST WITH INCREASED POTENTIAL FOR RIPPLES RIDING NORTHEAST IN
THE FLOW. MAIN TROUGH AXIS BACK IN MINNESOTA WITH ECMWF HAVING TWO
CONSECUTIVE RUNS OF SHOWING A MUCH MORE POTENT VORT CENTER.
THURSDAY NIGHT AND FRIDAY - CONFIDENCE...LOW
12Z AND 00Z ECMWF SHOWING A RATHER SIGNIFICANT SHORTWAVE/VORT MAX
CRASHING INTO THE AREA WITH ABUNDANT QPF. SURFACE LOW PRESSURE WOULD
TRACK SOUTH OF THE AREA WITH A SIGGY RAIN EVENT WITH DEF ZONE PRECIP
SHIELD ACROSS MUCH OF WI. THE GFS AND GEM ARE WEAKER WITH THE UPPER
WAVE CROSSING WI AND IMPLY DRYING WORKING IN WITH HIGH PRESSURE.
LOTS TO SORT OUT YET WITH THIS SYSTEM...BUT THE ECMWF HAS SHOWN SOME
CONSISTENCY YET THERE IS SOME CONSENSUS BETWEEN THE GEM AND GFS.
SATURDAY - CONFIDENCE...LOW TO MEDIUM
WHILE THE DETAILS BETWEEN THE MODELS VARY THE CONSENSUS IS FOR GOING
WITH A DRY FORECAST AS SYSTEM SHIFTS AWAY.
&&
.AVIATION/12Z TAFS/...PATCHY MVFR STRATUS AND FOG WILL CLEAR AROUND
OR SHORTLY AFTER ISSUANCE...WITH VFR CONDITIONS THROUGH THE PERIOD.
NORTH WINDS WILL BE GUSTY FOR A TIME AT EASTERN TAF SITES THIS
MORNING...THEN WEAKEN THIS AFTERNOON AS THEY SHIFT NORTHEAST.WILL
HAVE TO WATCH FOR PATCHY FOG AT KENW TONIGHT...WITH DEW POINTS
HOLDING UP A BIT MORE THAN INLAND AREAS...AND LAND BREEZE NOT AS
SIGNIFICANT A FACTOR AS AT KMKE.
&&
.MARINE...WILL NOT ISSUE A SMALL CRAFT ADVISORY AT THIS TIME...EVEN
THOUGH WINDS BECOME FAVORABLE FOR A TIME AS THEY SHIFT FROM OFFSHORE
EARLY TO THE NORTH...AND THEN NORTHEAST THROUGH THE MORNING INTO THE
EARLY AFTERNOON. GRADIENT WEAKENS WITH THE MORE FAVORABLE FETCH
REDUCING WIND SPEEDS WHICH WILL LIMIT WAVE HEIGHTS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM/AFK
MONDAY THROUGH SATURDAY...COLLAR
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
334 AM CDT SUN SEP 9 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH.
SCATTERED SHOWERS DEVELOPING IN REGION OF LAND BREEZE CONVERGENCE
OVER MID-LAKE IN WAKE OF DEPARTING SHORT WAVE. FORECAST SOUNDINGS
SHOW FAVORABLE DELTA T AND NORTH-NORTHEAST FLOW DEVELOPING BELOW 5K
FT...WITH NAM...GFS AND RUC 1000-900MB LAYER WIND/CONVERGENCE
FORECASTS INDICATING POTENTIAL OF SHOWERS BRUSHING THE SHORE BETWEEN
12Z AND 18Z. WILL KEEP SOME POPS ALONG THE SHORE FROM MILWAUKEE
SOUTH.
OTHERWISE DRY TROUGH THE PERIOD WITH UPPER RIDGING AND SURFACE HIGH
PRESSURE BUILDING OVER THE REGION...WITH COOL TEMPERATURES. 925MB
TEMPERATURES SUPPORT DAYTIME HIGHS IN THE LOW TO MID 70S WEST TO
AROUND 70 EAST. GOOD RADIATIONAL CONDITIONS TONIGHT WILL ALLOW LOWS
TO FALL INTO THE MID 40S AWAY FROM THE LAKE.
MONDAY THROUGH WEDNESDAY - CONFIDENCE...MEDIUM
BROAD 500 MILLIBAR ANTICYCLONIC FLOW ACROSS THE CWA THIS PERIOD.
SURFACE/850 HIGHS TO THE EAST. A WARMER SOUTHERLY REGIME KICKS IN.
500 MILLIBAR FLOW BECOMES MORE SOUTHWEST ON WEDNESDAY THOUGH BEST
FORCING...BOTH ALOFT AND IN THE LOW LEVELS...REMAINS TO THE NORTH
AND NORTHWEST OF THE CWA. 925 TEMPS SLOW TO RESPOND MONDAY...BUT A
SLIGHT WARMING NOTED. A MORE PRONOUNCED WARMING ON TUESDAY WITH 925
TEMPS BACK TO THE LOW 20S CELSIUS...WITH POSSIBLE MID 20S WEDNESDAY
WITH SOUTHWEST WINDS MAINTAINING THE WARM AIRMASS AHEAD OF THE
FRONT. SO TEMPS WELL INTO THE
WEDNESDAY NIGHT AND THURSDAY - CONFIDENCE...LOW
SURFACE BOUNDARY AND 850 BAROCLINIC ZONE SAGS INTO SRN WI THIS
PERIOD WITH PRECIP CHANCES INCREASING. 500 MILLIBAR FLOW BECOMES
SOUTHWEST WITH INCREASED POTENTIAL FOR RIPPLES RIDING NORTHEAST IN
THE FLOW. MAIN TROUGH AXIS BACK IN MINNESOTA WITH ECMWF HAVING TWO
CONSECUTIVE RUNS OF SHOWING A MUCH MORE POTENT VORT CENTER.
THURSDAY NIGHT AND FRIDAY - CONFIDENCE...LOW
12Z AND 00Z ECMWF SHOWING A RATHER SIGNIFICANT SHORTWAVE/VORT MAX
CRASHING INTO THE AREA WITH ABUNDANT QPF. SURFACE LOW PRESSURE WOULD
TRACK SOUTH OF THE AREA WITH A SIGGY RAIN EVENT WITH DEF ZONE PRECIP
SHIELD ACROSS MUCH OF WI. THE GFS AND GEM ARE WEAKER WITH THE UPPER
WAVE CROSSING WI AND IMPLY DRYING WORKING IN WITH HIGH PRESSURE.
LOTS TO SORT OUT YET WITH THIS SYSTEM...BUT THE ECMWF HAS SHOWN SOME
CONSISTENCY YET THERE IS SOME CONSENSUS BETWEEN THE GEM AND GFS.
SATURDAY - CONFIDENCE...LOW TO MEDIUM
WHILE THE DETAILS BETWEEN THE MODELS VARY THE CONSENSUS IS FOR GOING
WITH A DRY FORECAST AS SYSTEM SHIFTS AWAY.
&&
.AVIATION/12Z TAFS/...PATCHY MVFR STRATUS AND FOG WILL CLEAR AROUND OR
SHORTLY AFTER ISSUANCE...WITH VFR CONDITIONS THROUGH THE PERIOD.
NORTH WINDS WILL BE GUSTY FOR A TIME AT EASTERN TAF SITES THIS
MORNING...THEN WEAKEN THIS AFTERNOON AS THEY SHIFT NORTHEAST.WILL
HAVE TO WATCH FOR PATCHY FOG AT KENW TONIGHT...WITH DEW POINTS
HOLDING UP A BIT MORE THAN INLAND AREAS...AND LAND BREEZE NOT AS
SIGNIFICANT A FACTOR AS AT KMKE.
&&
.MARINE...WILL NOT ISSUE A SMALL CRAFT ADVISORY AT THIS TIME...EVEN
THOUGH WINDS BECOME FAVORABLE FOR A TIME AS THEY SHIFT FROM OFFSHORE
EARLY TO THE NORTH...AND THEN NORTHEAST THROUGH THE MORNING INTO THE
EARLY AFTERNOON. GRADIENT WEAKENS WITH THE MORE FAVORABLE FETCH
REDUCING WIND SPEEDS WHICH WILL LIMIT WAVE HEIGHTS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
319 AM CDT TUE SEP 11 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
319 AM CDT TUE SEP 11 2012
MAIN FORECAST CONCERNS ARE ON FIRE WEATHER TODAY...THEN
PRECIPITATION CHANCES AND TRENDS WEDNESDAY THROUGH THURSDAY NIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED DEEP TROUGHING OVER SOUTHWEST CANADA INTO THE PACIFIC
NORTHWEST AND RIDGING DOWNSTREAM FROM THE CENTRAL PLAINS INTO THE
WESTERN GREAT LAKES REGION. SHORTWAVES OF NOTE INCLUDE ONE OVER
NORTHWEST SOUTH DAKOTA...THEN A COMPLEX OF THEM IN THE MONSOONAL
MOISTURE ACROSS THE DESERT SOUTHWEST. ASSOCIATED WITH THE SOUTH
DAKOTA SHORTWAVE IS A SURFACE LOW JUST NORTH OF PIERRE. A TIGHT
PRESSURE GRADIENT EXISTS AHEAD OF THIS LOW INTO THE FORECAST
AREA...RESULTING IN BREEZY SOUTH WINDS. THESE WINDS HAVE KEPT
TEMPERATURES UP IN THE MID 50S TO MID 60S. HIGHER ALOFT...AT
850MB...PROFILER DATA SHOWED A SOUTHWEST 35-50 KT JET EXTENDING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA...ADVECTING WARM
AIR NORTHEASTWARD. 850MB TEMPS HAVE CLIMBED TO 18-22C PER RAP
ANALYSIS...COMPARED TO 00Z RAOBS WHICH WERE BETWEEN 16-18C.
AIRMASS ALSO REMAINS QUITE DRY ACROSS THE CENTRAL PLAINS INTO THE
FORECAST AREA...NOTED BY GOES SOUNDER PRECIPITABLE WATER VALUES OF
0.5-0.6 INCHES OR 60 PERCENT OF NORMAL. ALSO REFLECTIVE OF THE DRY
AIR WAS THE 00Z MPX SOUNDING WHICH HAD DEWPOINT DEPRESSIONS OF 15C
OR MORE FROM THE SURFACE TO 350MB. THE 00Z OAX SOUNDING WAS EVEN
DRIER. SATELLITE IMAGERY DEPICTING ONLY A LITTLE CIRRUS OVER THE
FORECAST AREA.
TODAY AND TONIGHT...MODELS TAKE THE DEEP SOUTHWEST CANADA TROUGH
EASTWARD INTO SOUTH CENTRAL CANADA BY 12Z WEDNESDAY. AS THIS TROUGH
PUSHES EAST...IT WILL PICK UP THE SHORTWAVE AND SURFACE LOW IN SOUTH
DAKOTA...LIFTING THEM INTO NORTHERN ONTARIO. THE ASSOCIATED COLD
FRONT IS TRENDING SLIGHTLY FASTER...NOW PROGGED TO REACH AROUND LA
CROSSE WI AT 12Z WEDNESDAY. THE WARM AIR SURGE AHEAD OF THE FRONT
CONTINUES TODAY WITH 850MB TEMPS PROGGED TO TOP OUT AT 20-22C FOR
18Z. THESE ARE NEAR 2 STANDARD DEVIATIONS ABOVE NORMAL. PLENTY OF
DRY AIR REMAINS...AND WITH 925MB SOUTHWEST WINDS OF 25-30 KT
PROMOTING MIXING AS WELL AS PLENTY OF SUN OUTSIDE OF SOME CIRRUS
LATE IN THE DAY...SHOULD HAVE NO PROBLEM MIXING UP TO THOSE 850MB
TEMPS. THUS...ANTICIPATING HIGHS SIMILAR TO THE PREVIOUS
FORECASTS...FROM THE MID 80S TO LOW 90S. GIVEN THE DRY AIR...BREEZY
CONDITIONS AND WARM TEMPERATURES...CRITICAL FIRE WEATHER CONDITIONS
ARE LIKELY. SEE FIRE WEATHER DISCUSSION FOR MORE DETAILS. FOR
TONIGHT...ALTHOUGH THE FRONT IS MOVING IN SLIGHTLY FASTER...ALL THE
FRONTOGENETIC FORCING AND MOISTURE STILL REMAINS NORTHWEST OF THE
FORECAST AREA. THEREFORE...EXPECTING DRY CONDITIONS AND ONLY A
GRADUAL INCREASE IN CLOUDS. WARM NIGHT ON TAP GIVEN WARM START
AND BREEZY WINDS AHEAD OF THE FRONT. MOST LOCATIONS SHOULD SEE LOWS
IN THE 60S.
WEDNESDAY AND WEDNESDAY NIGHT...ON THE WEST SIDE OF THE DEEP
SOUTHWEST CANADA TROUGH...MODELS ARE IN GOOD AGREEMENT DROPPING A
POTENT SHORTWAVE DOWN INTO THE NORTHERN PLAINS BY 12Z THURSDAY. THIS
SHORTWAVE LOOKS TO HELP KICK OUT ALL OF THE MONSOONAL SHORTWAVES...
EJECTING THEM NORTHEAST ACROSS THE FORECAST AREA. IT APPEARS A
COMBINATION OF THESE VARIOUS SHORTWAVES...ALONG WITH THE POTENT
SHORTWAVE TROUGH...WILL HELP TO KEEP THE COLD FRONT THAT IS NEAR LA
CROSSE AT 12Z WEDNESDAY MOVING TO THE EAST. OF INTEREST...THOUGH...
IS THE FORCING BEHIND THIS COLD FRONT. MODELS DEPICT AN 80-120 KT
JET AT THE TROPOPAUSE PERSISTING BOTH WEDNESDAY AND WEDNESDAY NIGHT
FROM CENTRAL MINNESOTA INTO NORTHERN ONTARIO...PLACING THE FORECAST
AREA IN THE RIGHT ENTRANCE REGION FOR UPPER LEVEL DIVERGENCE. LOWER
IN THE TROPOSPHERE...PLENTY OF LOW TO MID LEVEL FRONTOGENESIS
EXISTS...THOUGH THERE ARE SOME DIFFERENCES IN THE STRENGTH. FOR
EXAMPLE...THE 11.00Z NAM/REGIONAL CANADIAN ARE QUITE A BIT WEAKER
THAN THE 11.00Z GFS/UKMET AND AS SUCH IS A LOT LIGHTER WHEN IT COMES
TO ITS QPF FORECAST. IN FACT...THE 11.00Z NAM DEPICTS VERY LITTLE
RAIN FOR LOCATIONS NORTH OF I-90. CERTAINLY PLENTY OF MOISTURE
EXISTS WITH BOTH THE 11.00Z NAM AND GFS SHOWING AN AXIS OF 1-1.4
INCHES OF PRECIPITABLE WATER WHERE THE FRONTOGENESIS IS. GIVEN ALL
THE FORCING...WOULD HAVE TO THINK A WETTER SOLUTION IS MORE LIKELY.
SREF PROBABILITIES DEPICTING SOME SIMILAR UNCERTAINTY WITH HIGHER
PROBABILITIES OF PRECIPITATION SOUTH OF I-90. WILL TAILOR FORECAST
THIS WAY UNTIL MODELS CAN GET INTO BETTER AGREEMENT. DID REMOVE
THUNDER AS LAPSE RATES UNDER THE FRONTOGENETICAL BAND ARE MAINLY
MOIST-ADIABATIC. THERE IS SOME NEGATIVE EPV RESULTING FROM SLANTWISE
INSTABILITY...SO A COUPLE LIGHTNING STRIKES CANNOT BE RULED OUT.
HOWEVER...MENTIONING ISOLATED THUNDER FOR A WIDESPREAD AREA SEEMS
TOO HIGH OF A PROBABILITY. TEMPERATURES ARE QUITE TRICKY...SINCE
WHERE IT RAINS READINGS WILL BE HELD DOWN DUE TO EVAPORATIVE
COOLING. CERTAINLY WITH THE FASTER FRONT AND INCREASING CLOUDS
THROUGH THE DAY WEDNESDAY...HAVE HAD TO COOL HIGHS DOWN. FOR
NOW...HAVE TAKEN A BLEND OF GUIDANCE FOR BOTH HIGHS AND LOWS...WITH
A FALLING TEMP TREND IN THE AFTERNOON FOR THE PRECIPITATION THAT
DEVELOPS.
THURSDAY AND THURSDAY NIGHT...SOME DIFFERENCES EXIST WITH THE
HANDLING OF THE POTENT TROUGH DROPPING INTO THE NORTHERN PLAINS
THURSDAY MORNING. THE 11.00Z NAM IS AN OUTLIER...TAKING THE TROUGH
EAST TO LAKE SUPERIOR THURSDAY NIGHT. ALL OTHER MODELS
(GFS...ECMWF...UKMET...CANADIAN) HAVE THE TROUGH DIGGING DOWN
TOWARDS IOWA AND CLOSING OFF AS AN UPPER LOW. WILL FOLLOW THIS
GROUP...THOUGH EVEN WITHIN THESE THERE ARE ISSUES...MAINLY
PERTAINING TO HOW DEEP THE UPPER LOW BECOMES. FOR EXAMPLE...THE
DEEPEST 11.00Z CANADIAN PRODUCES A WAVE ALONG THE COLD FRONT...
CAUSING A DEFORMATION/FRONTOGENESIS AREA TO PERSIST OVER EASTERN
IOWA INTO THE FORECAST AREA THROUGH THE ENTIRE PERIOD. AS SUCH...THE
CANADIAN KEEPS THE AREA IN MODERATE TO HEAVY RAIN. THERE HAVE BEEN
PAST ECMWF AND GFS RUNS THAT HAVE SUGGESTED THIS SCENARIO...BUT THE
LATEST 11.00Z GFS AND ECMWF SUGGEST THE FRONTOGENESIS ZONE WILL BE
ABLE TO CONTINUE PUSHING EASTWARD AND NEARLY OUT OF THE AREA BY 12Z
FRIDAY. FOR NOW WILL LEAN TOWARDS THE GFS/ECMWF CONSENSUS BEING IN
THE MIDDLE OF THE NAM/CANADIAN EXTREMES...BUT REALIZE THIS PORTION
OF THE FORECAST HAS SOME UNCERTAINTY. ONE THING THAT DOES SEEM SURE
IS THAT THE SOUTHEASTERN HALF OF THE FORECAST AREA WILL SEE RAIN
THURSDAY WITH THE FRONTOGENESIS ZONE IN PLACE THERE BY ALL MODELS.
THUS...PRECIPITATION CHANCES RANGE FROM 70-90 THERE. LOWER CHANCES
OF PRECIPITATION EXIST ELSEWHERE WITH TIMING ISSUES OF THE
FRONTOGENESIS ZONE MOVING OFF. ALTHOUGH MOST MODELS HAVE
PRECIPITATION MOVING OUT OF THE FORECAST AREA THURSDAY NIGHT...
KEEPING AT LEAST A 20 PERCENT CHANCE EVERYWHERE TO ACCOUNT FOR THE
CANADIAN AND PREVIOUS GFS/ECMWF RUNS. MUCH COOLER TEMPERATURES
ANTICIPATED DURING THIS PERIOD...DUE TO A COMBINATION OF COLD
ADVECTION BEHIND THE FRONT KNOCKING 850MB TEMPS DOWN TO 6-8C...AS
WELL AS EVAPORATIVE/DYNAMIC COOLING WHERE IT IS RAINING. POTENTIAL
EXISTS FOR HIGHS ON THURSDAY IN SAY CRAWFORD COUNTY TO NOT GET ABOVE
60.
.LONG TERM...FRIDAY THROUGH MONDAY NIGHT
319 AM CDT TUE SEP 11 2012
FORECAST DURING THIS PERIOD HIGHLY DEPENDENT ON THE EVOLUTION OF THE
UPPER LEVEL LOW THAT IS EXPECTED TO BECOME CLOSED OFF DURING THE DAY
ON FRIDAY SOMEWHERE ACROSS THE UPPER MIDWEST...WITH THE POTENTIAL TO
LINGER INTO THE FIRST PART OF THE UPCOMING WEEKEND. BY 12Z
FRIDAY...SIGNIFICANT MODEL SPREAD IN LOCATION/STRENGTH OF THE UPPER
LEVEL FEATURE. THE 11.00Z GFS WAS MORE PROGRESSIVE WITH THE
SYSTEM...PUSHING IT QUICKLY EASTWARD BY 12Z SATURDAY SUCH THAT THE
FORECAST AREA WOULD BE DRY. MEANWHILE THE 10.12Z ECMWF AND 11.00Z
CANADIAN WERE STRONGER/SLOWER SOLUTIONS...WHICH PIVOTED MORE
ACROSS THE FORECAST AREA. OF NOTE WAS THE 11.00Z CANADIAN WHICH
DEPICTED SEVERAL DEFORMATION RAIN BANDS FRIDAY NIGHT INTO SATURDAY
RESULTING IN A LARGE SWATH OF MODERATE TO HEAVY RAINFALL ACROSS
PORTIONS OF THE AREA. TO ADD TO THE UNCERTAINTY...THE LATEST
11.00Z ECMWF CAME IN MUCH FASTER THAN ALL GUIDANCE AND QUITE
DIFFERENT FROM ITS PREVIOUS RUN. THIS SOLUTION WOULD MEAN MOST OF
FRIDAY INTO THE WEEKEND THE FORECAST AREA WOULD BE DRY WITH NEAR
NORMAL TEMPERATURES. 11.00Z GFS ENSEMBLES REFLECT THE SAME
UNCERTAINTY ON THE UPPER LOW DEPTH/TRACK THAT THE INDIVIDUAL
MODELS SHOW.
GIVEN THE LARGE VARIABILITY IN SOLUTIONS...AND POOR RUN-TO-RUN MODEL
CONSISTENCY...A MODEL CONSENSUS IS APPROPRIATE WHICH KEEPS
HIGHER PRECIPITATIONS CHANCES FRIDAY/FRIDAY NIGHT CONFINED EAST OF
THE MISSISSIPPI RIVER...THEN REDUCES TO JUST 20 PERCENT ON SATURDAY.
REGARDING TEMPERATURES...TRICKY AS WELL...THOUGH FRIDAY LOOKS TO
BE THE COOLEST DAY POTENTIALLY WITH MORE CLOUDS AND HIGHER
PRECIPITATION CHANCES. MODERATING TEMPERATURES TO NEAR NORMAL BY
SUNDAY WITH WEAK NORTHWEST TO NEAR ZONAL FLOW EXPECTED. GOING INTO
EARLY NEXT WEEK...ANOTHER DIGGING UPPER TROUGH WITH SURFACE FRONT
LEADS TO LOW END RAIN CHANCES AND COOLER TEMPERATURES FOR MONDAY
INTO MONDAY NIGHT. PLENTY OF UNCERTAINTY EXISTS TOO ON THIS
DIGGING UPPER TROUGH.
&&
.AVIATION...
1100 PM CDT MON SEP 10 2012
TIGHT PRESSURE GRADIENT WILL CONTINUE THROUGH TUESDAY...WITH SOME
SLACKENING AS A COLD FRONT STARTS TO PUSH IN FROM THE WEST TUE
NIGHT. TUE AFTERNOON GUSTS OF 30+ KTS ARE LIKELY. MEANWHILE FOR THE
OVERNIGHT...WINDS OFF THE SFC WILL STAY STRONG TONIGHT...RESULTING
IN SOME LLWS CONCERNS. 2 KFT WINDS OF 45 TO 50 KTS ARE EXPECTED FROM
THROUGH ABOUT 15Z TUE. LLWS IS HIGHLIGHTED IN THE TAFS FOR THE
OVERNIGHT HOURS...AND WILL CONTINUE THIS MENTION.
THE FRONT SLOWS UP AS IT MOVES OVER THE UPPER MISSISSIPPI
RIVER...PROBABLY NOT PUSHING EAST OF KRST/KLSE UNTIL LATE TUE-WED.
THERE WILL BE SOME -SHRA WITH THE BOUNDARY...PERHAPS AN ISOLD
TS...BUT THE BETTER FORCING/SATURATION LIES POST FRONT...AND SO WILL
THE PCPN CHANCES. THE POTENTIAL FOR MVFR CIGS LIKELY HOLDS OFF UNTIL
WED NIGHT.
&&
.CLIMATE...TODAY
340 PM CDT SUN SEP 9 2012
HIGH TEMPERATURES WILL CLIMB TO AROUND 90 DEGREES MAINLY NORTHWEST
OF A CHARLES CITY IOWA TO BLACK RIVER FALLS LINE ON TUESDAY. THE
RECORD HIGHS FOR THIS DATE ARE...
LA CROSSE WI - 97 IN 1897
MEDFORD WI - 95 IN 1900
ROCHESTER MN - 94 IN 1931
AUSTIN MN - 92 IN 1948
CHARLES CITY IA - 96 IN 2000
DECORAH IA - 97 IN 1895
&&
.FIRE WEATHER...TODAY
319 AM CDT TUE SEP 11 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN ON TAP FROM LATE THIS
MORNING THROUGH THIS EVENING ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA. SOUTH TO SOUTHWEST WINDS OF 20 TO 25 MPH WITH
GUSTS OF 30 TO 40 MPH...AND RELATIVE HUMIDITY VALUES OF 20 TO
25 PERCENT ARE EXPECTED...ESPECIALLY DURING THE AFTERNOON HOURS. THE
COMBINATION OF STRONG WINDS AND LOW RH VALUES WILL PRODUCE DANGER
CONDITIONS FOR WILDFIRES. THE RED FLAG WARNING REMAINS IN EFFECT
FROM OLMSTED COUNTY TO CHICKASAW COUNTY WESTWARD. THE WINDS WILL
SUBSIDE LATE TUESDAY EVENING AS A COLD FRONT APPROACHES THE AREA.
HOWEVER...THE COLD FRONT WILL RESULT IN A WIND SHIFT...WITH WINDS
SWITCHING TO THE NORTHWEST. CONDITIONS SHOULD IMPROVE THROUGH THE
NIGHT INTO EARLY WEDNESDAY MORNING AS THE PRESSURE GRADIENT
WEAKENS...TEMPERATURES COOL AND PRECIPITATION EVENTUALLY DEVELOPS.
THROUGH COORDINATION WITH LOCAL FIRE WEATHER PARTNERS
YESTERDAY...LOCATIONS NEAR AND EAST OF THE MISSISSIPPI RIVER HAVE
NOT BEEN INCLUDED IN ANY FIRE WEATHER HEADLINES BECAUSE OF RECENT
RAINS AND FUELS NOT CONDUCIVE TO EXPLOSIVE FIRE GROWTH. SOME DRY
AREAS WILL HAVE TO BE WATCHED CLOSELY...ESPECIALLY SOUTH FACING
SLOPES AND SANDY AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 AM CDT TUE SEP 11 2012
WI...NONE.
MN...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR MNZ086-087-094-095.
IA...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR IAZ008-009-018-019.
&&
$$
SHORT TERM...AJ
LONG TERM...ZT
AVIATION.......RIECK
CLIMATE........BOYNE
FIRE WEATHER...WETENKAMP/AJ
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
935 AM EDT TUE SEP 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THROUGH THURSDAY. DRY WEATHER ALONG
WITH SLIGHTLY COOLER THAN NORMAL TEMPERATURES WILL CONTINUE.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DRY HIGH PRESSURE IS RIDGING INTO THE FORECAST AREA FROM THE
NORTH. AN AREA OF MID-LEVEL CLOUDINESS COVERS THE NORTHWEST PART
OF THE FORECAST AREA. THIS MOISTURE IS TRAPPED UNDER A STRONG
INVERSION AND IS BEING SUPPORTED BY LIFT ASSOCIATED WITH A MID-
LEVEL SHORTWAVE TROUGH. THE RAP SHOWS THIS MOISTURE TENDING TO
SHIFT SOUTH AND WEST THIS AFTERNOON. ALSO EXPECT HEATING AND MIXING
WILL RESULT IN BREAKS IN THE CLOUDINESS. STILL...THE CLOUDINESS
SHOULD LIMIT THE TEMPERATURE RISE IN THE NORTHWEST PART AND WE
HAVE LOWED THE HIGH TEMPERATURE FORECAST A FEW DEGREES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AN UPPER-LEVEL RIDGE WILL BUILD INTO THE REGION WITH SURFACE HIGH
PRESSURE EXTENDING FROM THE MID-ATLANTIC THROUGH THE CAROLINAS TO
THE GULF COAST. WE CAN EXPECT MOSTLY CLEAR SKIES WITH NORTHEAST TO
EAST WINDS. AFTERNOON HUMIDITIES WILL BE LOW. THE TEMPERATURE
GUIDANCE WAS CLOSE. WE SHOULD SEE AFTERNOON HIGHS IN THE MID 80S
AND NIGHTTIME LOWS IN THE MID 50S TO AROUND 60.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE MODELS CONTINUE IN GOOD AGREEMENT WITH HIGH PRESSURE AND DRY
AIR DOMINATING THE REGION THROUGH THURSDAY NIGHT. AS THE HIGH
SHIFTS EASTWARD DURING THE WEEKEND...AN EASTERLY FLOW WILL
CIRCULATE INCREASING MOISTURE INTO THE FORECAST AREA AND
ISENTROPIC LIFT MAY LEAD TO SHOWERS. THE GFS ENSEMBLE MEANS
SUPPORT POPS OF 20 TO 30 PERCENT.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
SATELLITE SHOWS SOME MID LEVEL CLOUDS THIS MORNING ACROSS THE
UPSTATE AND NORTHERN MIDLANDS. THESE CLOUDS HAVE BEGUN TO DRIFT
SOUTHWARD AND WILL IMPACT CAE/CUB DURING THE MORNING HOURS.
OTHERWISE...EXPECT VFR CONDITIONS EXPECTED THROUGH THE 24 HOUR TAF
PERIOD. HIGH PRESSURE CENTERED TO OUR NORTH WILL MAINTAIN A DRY
ATMOSPHERE. EXPECT SOME SCATTERED CLOUDS THROUGH THE DAY WITH LIGHT
EAST WINDS.
EXTENDED AVIATION OUTLOOK...NO IMPACTS TO AVIATION EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1041 AM EDT TUE SEP 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY WEATHER WITH WARMING TEMPERATURES
EACH DAY THIS WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO REMOVE
MORNING FOG WORDING AND TO LOWER HIGHS BY A DEGREE BASED ON
RECENT TEMP TRENDS. OTHERWISE, FORECAST REMAINS UNCHANGED.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THAT THE UPPER OHIO
VALLEY IS ON THE NORTHEASTERN PERIPHERY OF A BROAD 500MB TROUGH
CENTERED ACROSS THE MISSOURI VALLEY AND THE GULF STATES. AT THE
SURFACE, A 1028MB HIGH IS CENTERED ACROSS WEST VIRGINIA AND IS
DOMINATING THE WEATHER PATTERN ACROSS THE EASTERN US WITH CLEAR
SKIES.
HIGH PRESSURE AND A DEEP LAYER OF DRY AIR ALOFT WILL CONTINUE TO
DOMINATE THE PATTERN THROUGH TONIGHT. ASIDE FROM LITTLE CIRRUS
PASSING NORTH OF THE AREA, SKIES WILL BE CLEAR WITH LIGHT
SOUTHERLY WINDS. TEMPS WILL RECOVER QUICKLY TODAY WITH HIGHS
CLOSE TO A MAV/MET BLEND IN THE MID 70S ACROSS MOST OF THE AREA.
ANOTHER NIGHT OF RADIATIONAL COOLING WITH PATCHY RIVER VALLEY FOG
CAN BE EXPECTED TONIGHT WITH LOWS AROUND 5 TO 10 DEGREES BELOW
SEASONAL NORMALS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
MIDWRN RIDGE ALOFT IS FORECAST TO SHIFT EWD AND AMPLIFY IN RESPONSE
TO CUTOFF LOW DIGGING ACRS WRN CANADA. WITH THE SFC HIGHS EWD
SHIFT...WARM ADVCTN WL RESUME UNDR THE SBSDNC REGIME/RISING HTS
ALOFT. TEMP MODERATION MAY THUS BE ANTICIPATED WITH AFTN HIGHS
RISING TO APPROX 5 DEGREES ABOVE THE SEASONAL AVERAGES.
STRNG RADIATIONAL COOLING WL AGAIN SPPRT SUB NORMAL LOWS ON
WEDNESDAY MRNG...BUT NR AVG READINGS ARE ANTICIPATED FOR THURSDAY
AND FRIDAY MRNG AS THE BNDRY LYR MSTR SLOWLY RISES. OVERALL TEMP
FORECAST WAS BASED ON PERSISTENCE WITH A TWEAK BASED ON RECENT GFS
AND NAM MOS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
ALTHOUGH MDLS RMN IN GENL AGRMNT THAT A CDFTN WL MOV ACRS THE UPR
OH VALLEY OVR THE WEEKEND...TIMING IS QNABLE AS IS NORMAL AT THIS
POINT IN THE FORECAST CYCLE. THE GFS CONTS TO BE THE FASTER
SOLN...WITH THE FRONT AFFECTING THE REGION SATURDAY/SATURDAY
NIGHT. AS THE ENSEMBLE MEAN LEANS MORE TWDS A SATURDAY NGT/SUNDAY
PASSAGE...HAVE GONE WITH THIS SCENARIO. HIGH PRES IS THEN FORECAST
TO SLIDE OVR THE AREA BY SUNDAY.
TEMPS WERE FORECASTED ABOVE THE AVERAGES FOR FRIDAY...THEN DROPPED TO
NR SEASONAL READINGS IN THE WAKE OF THE FRONT.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL PROVIDE FOR VFR CONDITIONS AND LIGHT WINDS
THROUGH THE TAF PERIOD.
.OUTLOOK /WEDNESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL MAINTAIN VFR CONDITIONS THROUGH FRIDAY WITH
ONLY BRIEF RESTRICTIONS IN VALLEY FOG POSSIBLE IN THE MORNING EACH
DAY. A FRONT APPROACHING FOR THE WEEKEND COULD POTENTIALLY BRING
SHOWERS ON SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
809 AM EDT TUE SEP 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY WEATHER WITH WARMING TEMPERATURES THIS
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
12Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH
LITTLE CHANGE TO THE FORECAST OTHER THAN TO ACCOUNT FOR THE LATEST
TRENDS IN TEMP AND DEW POINT.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THAT THE UPPER OHIO
VALLEY IS ON THE NORTHEASTERN PERIPHERY OF A BROAD 500MB TROUGH
CENTERED ACROSS THE MISSOURI VALLEY AND THE GULF STATES. AT THE
SURFACE, A 1028MB HIGH IS CENTERED ACROSS WEST VIRGINIA AND IS
DOMINATING THE WEATHER PATTERN ACROSS THE EASTERN US WITH CLEAR
SKIES. WITH COOL TEMPS THIS MORNING DROPPING INTO THE UPPER 30S
IN SOME LOCATIONS, THIS HAS ALLOWED FOR PATCHY DENSE FOG TO
DEVELOP IN THE WARMER RIVER VALLEYS.
HIGH PRESSURE AND A DEEP LAYER OF DRY AIR ALOFT WILL CONTINUE TO
DOMINATE THE PATTERN THROUGH TONIGHT. ASIDE FROM LITTLE CIRRUS
PASSING NORTH OF THE AREA, SKIES WILL BE CLEAR WITH LIGHT
SOUTHERLY WINDS. TEMPS WILL RECOVER QUICKLY TODAY AS PATCHY FOG
BURNS OFF, WITH HIGHS CLOSE TO A MAV/MET BLEND IN THE MID TO
UPPER 70S ACROSS THE AREA. ANOTHER NIGHT OF RADIATIONAL COOLING
CAN BE EXPECTED TONIGHT WITH LOWS AROUND 5 TO 10 DEGREES BELOW
SEASONAL NORMALS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
MIDWRN RIDGE ALOFT IS FORECAST TO SHIFT EWD AND AMPLIFY IN RESPONSE
TO CUTOFF LOW DIGGING ACRS WRN CANADA. WITH THE SFC HIGHS EWD
SHIFT...WARM ADVCTN WL RESUME UNDR THE SBSDNC REGIME/RISING HTS
ALOFT. TEMP MODERATION MAY THUS BE ANTICIPATED WITH AFTN HIGHS
RISING TO APPROX 5 DEGREES ABOVE THE SEASONAL AVERAGES.
STRNG RADIATIONAL COOLING WL AGAIN SPPRT SUB NORMAL LOWS ON
WEDNESDAY MRNG...BUT NR AVG READINGS ARE ANTICIPATED FOR THURSDAY
AND FRIDAY MRNG AS THE BNDRY LYR MSTR SLOWLY RISES. OVERALL TEMP
FORECAST WAS BASED ON PERSISTENCE WITH A TWEAK BASED ON RECENT GFS
AND NAM MOS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
ALTHOUGH MDLS RMN IN GENL AGRMNT THAT A CDFTN WL MOV ACRS THE UPR
OH VALLEY OVR THE WEEKEND...TIMING IS QNABLE AS IS NORMAL AT THIS
POINT IN THE FORECAST CYCLE. THE GFS CONTS TO BE THE FASTER
SOLN...WITH THE FRONT AFFECTING THE REGION SATURDAY/SATURDAY
NIGHT. AS THE ENSEMBLE MEAN LEANS MORE TWDS A SATURDAY NGT/SUNDAY
PASSAGE...HAVE GONE WITH THIS SCENARIO. HIGH PRES IS THEN FORECAST
TO SLIDE OVR THE AREA BY SUNDAY.
TEMPS WERE FORECASTED ABOVE THE AVERAGES FOR FRIDAY...THEN DROPPED TO
NR SEASONAL READINGS IN THE WAKE OF THE FRONT.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
CALM WINDS AND CLEAR SKIES ARE PROVIDING FOR OPTIMAL RADIATIONAL
COOLING. WITH VERY LOW DEWPOINTS...DO NOT THINK THERE WILL BE MUCH
IN THE WAY OF FOG OUTSIDE OF THE RIVER VALLEY LOCATIONS. AS THIS FOG
LIFTS NEAR SUNRISE...THERE COULD BE A BRIEF PERIOD OF MVFR/IFR VSBYS
AT KDUJ/KMGW/KHLG AS WAS THE CASE YESTERDAY. OTHERWISE...HIGH
PRESSURE WILL PROVIDE FOR VFR CONDITIONS AND LIGHT WINDS THROUGH THE
REST OF THE PERIOD.
.OUTLOOK /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL MAINTAIN VFR CONDITIONS THROUGH FRIDAY WITH ONLY
BRIEF RESTRICTIONS IN VALLEY FOG POSSIBLE IN THE MORNING EACH DAY.
A FRONT APPROACHING FOR THE WEEKEND COULD POTENTIALLY BRING SHOWERS
ON SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
620 AM CDT TUE SEP 11 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
319 AM CDT TUE SEP 11 2012
MAIN FORECAST CONCERNS ARE ON FIRE WEATHER TODAY...THEN
PRECIPITATION CHANCES AND TRENDS WEDNESDAY THROUGH THURSDAY NIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED DEEP TROUGHING OVER SOUTHWEST CANADA INTO THE PACIFIC
NORTHWEST AND RIDGING DOWNSTREAM FROM THE CENTRAL PLAINS INTO THE
WESTERN GREAT LAKES REGION. SHORTWAVES OF NOTE INCLUDE ONE OVER
NORTHWEST SOUTH DAKOTA...THEN A COMPLEX OF THEM IN THE MONSOONAL
MOISTURE ACROSS THE DESERT SOUTHWEST. ASSOCIATED WITH THE SOUTH
DAKOTA SHORTWAVE IS A SURFACE LOW JUST NORTH OF PIERRE. A TIGHT
PRESSURE GRADIENT EXISTS AHEAD OF THIS LOW INTO THE FORECAST
AREA...RESULTING IN BREEZY SOUTH WINDS. THESE WINDS HAVE KEPT
TEMPERATURES UP IN THE MID 50S TO MID 60S. HIGHER ALOFT...AT
850MB...PROFILER DATA SHOWED A SOUTHWEST 35-50 KT JET EXTENDING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA...ADVECTING WARM
AIR NORTHEASTWARD. 850MB TEMPS HAVE CLIMBED TO 18-22C PER RAP
ANALYSIS...COMPARED TO 00Z RAOBS WHICH WERE BETWEEN 16-18C.
AIRMASS ALSO REMAINS QUITE DRY ACROSS THE CENTRAL PLAINS INTO THE
FORECAST AREA...NOTED BY GOES SOUNDER PRECIPITABLE WATER VALUES OF
0.5-0.6 INCHES OR 60 PERCENT OF NORMAL. ALSO REFLECTIVE OF THE DRY
AIR WAS THE 00Z MPX SOUNDING WHICH HAD DEWPOINT DEPRESSIONS OF 15C
OR MORE FROM THE SURFACE TO 350MB. THE 00Z OAX SOUNDING WAS EVEN
DRIER. SATELLITE IMAGERY DEPICTING ONLY A LITTLE CIRRUS OVER THE
FORECAST AREA.
TODAY AND TONIGHT...MODELS TAKE THE DEEP SOUTHWEST CANADA TROUGH
EASTWARD INTO SOUTH CENTRAL CANADA BY 12Z WEDNESDAY. AS THIS TROUGH
PUSHES EAST...IT WILL PICK UP THE SHORTWAVE AND SURFACE LOW IN SOUTH
DAKOTA...LIFTING THEM INTO NORTHERN ONTARIO. THE ASSOCIATED COLD
FRONT IS TRENDING SLIGHTLY FASTER...NOW PROGGED TO REACH AROUND LA
CROSSE WI AT 12Z WEDNESDAY. THE WARM AIR SURGE AHEAD OF THE FRONT
CONTINUES TODAY WITH 850MB TEMPS PROGGED TO TOP OUT AT 20-22C FOR
18Z. THESE ARE NEAR 2 STANDARD DEVIATIONS ABOVE NORMAL. PLENTY OF
DRY AIR REMAINS...AND WITH 925MB SOUTHWEST WINDS OF 25-30 KT
PROMOTING MIXING AS WELL AS PLENTY OF SUN OUTSIDE OF SOME CIRRUS
LATE IN THE DAY...SHOULD HAVE NO PROBLEM MIXING UP TO THOSE 850MB
TEMPS. THUS...ANTICIPATING HIGHS SIMILAR TO THE PREVIOUS
FORECASTS...FROM THE MID 80S TO LOW 90S. GIVEN THE DRY AIR...BREEZY
CONDITIONS AND WARM TEMPERATURES...CRITICAL FIRE WEATHER CONDITIONS
ARE LIKELY. SEE FIRE WEATHER DISCUSSION FOR MORE DETAILS. FOR
TONIGHT...ALTHOUGH THE FRONT IS MOVING IN SLIGHTLY FASTER...ALL THE
FRONTOGENETIC FORCING AND MOISTURE STILL REMAINS NORTHWEST OF THE
FORECAST AREA. THEREFORE...EXPECTING DRY CONDITIONS AND ONLY A
GRADUAL INCREASE IN CLOUDS. WARM NIGHT ON TAP GIVEN WARM START
AND BREEZY WINDS AHEAD OF THE FRONT. MOST LOCATIONS SHOULD SEE LOWS
IN THE 60S.
WEDNESDAY AND WEDNESDAY NIGHT...ON THE WEST SIDE OF THE DEEP
SOUTHWEST CANADA TROUGH...MODELS ARE IN GOOD AGREEMENT DROPPING A
POTENT SHORTWAVE DOWN INTO THE NORTHERN PLAINS BY 12Z THURSDAY. THIS
SHORTWAVE LOOKS TO HELP KICK OUT ALL OF THE MONSOONAL SHORTWAVES...
EJECTING THEM NORTHEAST ACROSS THE FORECAST AREA. IT APPEARS A
COMBINATION OF THESE VARIOUS SHORTWAVES...ALONG WITH THE POTENT
SHORTWAVE TROUGH...WILL HELP TO KEEP THE COLD FRONT THAT IS NEAR LA
CROSSE AT 12Z WEDNESDAY MOVING TO THE EAST. OF INTEREST...THOUGH...
IS THE FORCING BEHIND THIS COLD FRONT. MODELS DEPICT AN 80-120 KT
JET AT THE TROPOPAUSE PERSISTING BOTH WEDNESDAY AND WEDNESDAY NIGHT
FROM CENTRAL MINNESOTA INTO NORTHERN ONTARIO...PLACING THE FORECAST
AREA IN THE RIGHT ENTRANCE REGION FOR UPPER LEVEL DIVERGENCE. LOWER
IN THE TROPOSPHERE...PLENTY OF LOW TO MID LEVEL FRONTOGENESIS
EXISTS...THOUGH THERE ARE SOME DIFFERENCES IN THE STRENGTH. FOR
EXAMPLE...THE 11.00Z NAM/REGIONAL CANADIAN ARE QUITE A BIT WEAKER
THAN THE 11.00Z GFS/UKMET AND AS SUCH IS A LOT LIGHTER WHEN IT COMES
TO ITS QPF FORECAST. IN FACT...THE 11.00Z NAM DEPICTS VERY LITTLE
RAIN FOR LOCATIONS NORTH OF I-90. CERTAINLY PLENTY OF MOISTURE
EXISTS WITH BOTH THE 11.00Z NAM AND GFS SHOWING AN AXIS OF 1-1.4
INCHES OF PRECIPITABLE WATER WHERE THE FRONTOGENESIS IS. GIVEN ALL
THE FORCING...WOULD HAVE TO THINK A WETTER SOLUTION IS MORE LIKELY.
SREF PROBABILITIES DEPICTING SOME SIMILAR UNCERTAINTY WITH HIGHER
PROBABILITIES OF PRECIPITATION SOUTH OF I-90. WILL TAILOR FORECAST
THIS WAY UNTIL MODELS CAN GET INTO BETTER AGREEMENT. DID REMOVE
THUNDER AS LAPSE RATES UNDER THE FRONTOGENETICAL BAND ARE MAINLY
MOIST-ADIABATIC. THERE IS SOME NEGATIVE EPV RESULTING FROM SLANTWISE
INSTABILITY...SO A COUPLE LIGHTNING STRIKES CANNOT BE RULED OUT.
HOWEVER...MENTIONING ISOLATED THUNDER FOR A WIDESPREAD AREA SEEMS
TOO HIGH OF A PROBABILITY. TEMPERATURES ARE QUITE TRICKY...SINCE
WHERE IT RAINS READINGS WILL BE HELD DOWN DUE TO EVAPORATIVE
COOLING. CERTAINLY WITH THE FASTER FRONT AND INCREASING CLOUDS
THROUGH THE DAY WEDNESDAY...HAVE HAD TO COOL HIGHS DOWN. FOR
NOW...HAVE TAKEN A BLEND OF GUIDANCE FOR BOTH HIGHS AND LOWS...WITH
A FALLING TEMP TREND IN THE AFTERNOON FOR THE PRECIPITATION THAT
DEVELOPS.
THURSDAY AND THURSDAY NIGHT...SOME DIFFERENCES EXIST WITH THE
HANDLING OF THE POTENT TROUGH DROPPING INTO THE NORTHERN PLAINS
THURSDAY MORNING. THE 11.00Z NAM IS AN OUTLIER...TAKING THE TROUGH
EAST TO LAKE SUPERIOR THURSDAY NIGHT. ALL OTHER MODELS
(GFS...ECMWF...UKMET...CANADIAN) HAVE THE TROUGH DIGGING DOWN
TOWARDS IOWA AND CLOSING OFF AS AN UPPER LOW. WILL FOLLOW THIS
GROUP...THOUGH EVEN WITHIN THESE THERE ARE ISSUES...MAINLY
PERTAINING TO HOW DEEP THE UPPER LOW BECOMES. FOR EXAMPLE...THE
DEEPEST 11.00Z CANADIAN PRODUCES A WAVE ALONG THE COLD FRONT...
CAUSING A DEFORMATION/FRONTOGENESIS AREA TO PERSIST OVER EASTERN
IOWA INTO THE FORECAST AREA THROUGH THE ENTIRE PERIOD. AS SUCH...THE
CANADIAN KEEPS THE AREA IN MODERATE TO HEAVY RAIN. THERE HAVE BEEN
PAST ECMWF AND GFS RUNS THAT HAVE SUGGESTED THIS SCENARIO...BUT THE
LATEST 11.00Z GFS AND ECMWF SUGGEST THE FRONTOGENESIS ZONE WILL BE
ABLE TO CONTINUE PUSHING EASTWARD AND NEARLY OUT OF THE AREA BY 12Z
FRIDAY. FOR NOW WILL LEAN TOWARDS THE GFS/ECMWF CONSENSUS BEING IN
THE MIDDLE OF THE NAM/CANADIAN EXTREMES...BUT REALIZE THIS PORTION
OF THE FORECAST HAS SOME UNCERTAINTY. ONE THING THAT DOES SEEM SURE
IS THAT THE SOUTHEASTERN HALF OF THE FORECAST AREA WILL SEE RAIN
THURSDAY WITH THE FRONTOGENESIS ZONE IN PLACE THERE BY ALL MODELS.
THUS...PRECIPITATION CHANCES RANGE FROM 70-90 THERE. LOWER CHANCES
OF PRECIPITATION EXIST ELSEWHERE WITH TIMING ISSUES OF THE
FRONTOGENESIS ZONE MOVING OFF. ALTHOUGH MOST MODELS HAVE
PRECIPITATION MOVING OUT OF THE FORECAST AREA THURSDAY NIGHT...
KEEPING AT LEAST A 20 PERCENT CHANCE EVERYWHERE TO ACCOUNT FOR THE
CANADIAN AND PREVIOUS GFS/ECMWF RUNS. MUCH COOLER TEMPERATURES
ANTICIPATED DURING THIS PERIOD...DUE TO A COMBINATION OF COLD
ADVECTION BEHIND THE FRONT KNOCKING 850MB TEMPS DOWN TO 6-8C...AS
WELL AS EVAPORATIVE/DYNAMIC COOLING WHERE IT IS RAINING. POTENTIAL
EXISTS FOR HIGHS ON THURSDAY IN SAY CRAWFORD COUNTY TO NOT GET ABOVE
60.
.LONG TERM...FRIDAY THROUGH MONDAY NIGHT
319 AM CDT TUE SEP 11 2012
FORECAST DURING THIS PERIOD HIGHLY DEPENDENT ON THE EVOLUTION OF THE
UPPER LEVEL LOW THAT IS EXPECTED TO BECOME CLOSED OFF DURING THE DAY
ON FRIDAY SOMEWHERE ACROSS THE UPPER MIDWEST...WITH THE POTENTIAL TO
LINGER INTO THE FIRST PART OF THE UPCOMING WEEKEND. BY 12Z
FRIDAY...SIGNIFICANT MODEL SPREAD IN LOCATION/STRENGTH OF THE UPPER
LEVEL FEATURE. THE 11.00Z GFS WAS MORE PROGRESSIVE WITH THE
SYSTEM...PUSHING IT QUICKLY EASTWARD BY 12Z SATURDAY SUCH THAT THE
FORECAST AREA WOULD BE DRY. MEANWHILE THE 10.12Z ECMWF AND 11.00Z
CANADIAN WERE STRONGER/SLOWER SOLUTIONS...WHICH PIVOTED MORE
ACROSS THE FORECAST AREA. OF NOTE WAS THE 11.00Z CANADIAN WHICH
DEPICTED SEVERAL DEFORMATION RAIN BANDS FRIDAY NIGHT INTO SATURDAY
RESULTING IN A LARGE SWATH OF MODERATE TO HEAVY RAINFALL ACROSS
PORTIONS OF THE AREA. TO ADD TO THE UNCERTAINTY...THE LATEST
11.00Z ECMWF CAME IN MUCH FASTER THAN ALL GUIDANCE AND QUITE
DIFFERENT FROM ITS PREVIOUS RUN. THIS SOLUTION WOULD MEAN MOST OF
FRIDAY INTO THE WEEKEND THE FORECAST AREA WOULD BE DRY WITH NEAR
NORMAL TEMPERATURES. 11.00Z GFS ENSEMBLES REFLECT THE SAME
UNCERTAINTY ON THE UPPER LOW DEPTH/TRACK THAT THE INDIVIDUAL
MODELS SHOW.
GIVEN THE LARGE VARIABILITY IN SOLUTIONS...AND POOR RUN-TO-RUN MODEL
CONSISTENCY...A MODEL CONSENSUS IS APPROPRIATE WHICH KEEPS
HIGHER PRECIPITATIONS CHANCES FRIDAY/FRIDAY NIGHT CONFINED EAST OF
THE MISSISSIPPI RIVER...THEN REDUCES TO JUST 20 PERCENT ON SATURDAY.
REGARDING TEMPERATURES...TRICKY AS WELL...THOUGH FRIDAY LOOKS TO
BE THE COOLEST DAY POTENTIALLY WITH MORE CLOUDS AND HIGHER
PRECIPITATION CHANCES. MODERATING TEMPERATURES TO NEAR NORMAL BY
SUNDAY WITH WEAK NORTHWEST TO NEAR ZONAL FLOW EXPECTED. GOING INTO
EARLY NEXT WEEK...ANOTHER DIGGING UPPER TROUGH WITH SURFACE FRONT
LEADS TO LOW END RAIN CHANCES AND COOLER TEMPERATURES FOR MONDAY
INTO MONDAY NIGHT. PLENTY OF UNCERTAINTY EXISTS TOO ON THIS
DIGGING UPPER TROUGH.
&&
.AVIATION...TODAY INTO WEDNESDAY
620 AM CDT TUE SEP 11 2012
THE TIGHT PRESSURE GRADIENT WILL REMAIN OVER THE AREA TODAY...THEN
SLACKEN TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. LOW LEVEL
WIND SHEAR WILL REMAIN AN ISSUE UNTIL 14-15Z THIS MORNING...WITH
SOUTHWEST WINDS OF 35-40KTS ON TOP OF THE NOCTURNAL INVERSION. WITH
DIURNAL WARMING/MIXING...SOUTH WINDS BY LATE THIS MORNING AND FOR
THIS AFTERNOON WILL MIX/INCREASE INTO THE 15-25KT G25-35KT RANGE.
RIDGE TOP AND HIGHER TERRAIN AREAS LIKE KAUM/KRST WILL SEE THE
HIGHER END OF THE RANGE WHILE MOST RIVER VALLEY LOCATIONS WILL SEE
WIND SPEEDS CLOSER TO THE LOW END OF THE RANGE. WITH A DRY AIRMASS
AHEAD OF THE FRONT...GOOD VFR CONDITIONS ARE EXPECTED THRU TODAY/
TONIGHT.
THE FRONT WILL PUSH ACROSS THE AREA WED WITH THE MAIN INCREASE OF
MOISTURE AND LIFT BEHIND THE FRONT. CLOUDS WILL GRADUALLY INCREASE/
LOWER THRU THE DAY WED WITH SOME -SHRA MOVING INTO THE TAF SITES FOR
THE AFTERNOON.
&&
.CLIMATE...TODAY
340 PM CDT SUN SEP 9 2012
HIGH TEMPERATURES WILL CLIMB TO AROUND 90 DEGREES MAINLY NORTHWEST
OF A CHARLES CITY IOWA TO BLACK RIVER FALLS LINE ON TUESDAY. THE
RECORD HIGHS FOR THIS DATE ARE...
LA CROSSE WI - 97 IN 1897
MEDFORD WI - 95 IN 1900
ROCHESTER MN - 94 IN 1931
AUSTIN MN - 92 IN 1948
CHARLES CITY IA - 96 IN 2000
DECORAH IA - 97 IN 1895
&&
.FIRE WEATHER...TODAY
319 AM CDT TUE SEP 11 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN ON TAP FROM LATE THIS
MORNING THROUGH THIS EVENING ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA. SOUTH TO SOUTHWEST WINDS OF 20 TO 25 MPH WITH
GUSTS OF 30 TO 40 MPH...AND RELATIVE HUMIDITY VALUES OF 20 TO
25 PERCENT ARE EXPECTED...ESPECIALLY DURING THE AFTERNOON HOURS. THE
COMBINATION OF STRONG WINDS AND LOW RH VALUES WILL PRODUCE DANGER
CONDITIONS FOR WILDFIRES. THE RED FLAG WARNING REMAINS IN EFFECT
FROM OLMSTED COUNTY TO CHICKASAW COUNTY WESTWARD. THE WINDS WILL
SUBSIDE LATE TUESDAY EVENING AS A COLD FRONT APPROACHES THE AREA.
HOWEVER...THE COLD FRONT WILL RESULT IN A WIND SHIFT...WITH WINDS
SWITCHING TO THE NORTHWEST. CONDITIONS SHOULD IMPROVE THROUGH THE
NIGHT INTO EARLY WEDNESDAY MORNING AS THE PRESSURE GRADIENT
WEAKENS...TEMPERATURES COOL AND PRECIPITATION EVENTUALLY DEVELOPS.
THROUGH COORDINATION WITH LOCAL FIRE WEATHER PARTNERS
YESTERDAY...LOCATIONS NEAR AND EAST OF THE MISSISSIPPI RIVER HAVE
NOT BEEN INCLUDED IN ANY FIRE WEATHER HEADLINES BECAUSE OF RECENT
RAINS AND FUELS NOT CONDUCIVE TO EXPLOSIVE FIRE GROWTH. SOME DRY
AREAS WILL HAVE TO BE WATCHED CLOSELY...ESPECIALLY SOUTH FACING
SLOPES AND SANDY AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 AM CDT TUE SEP 11 2012
WI...NONE.
MN...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR MNZ086-087-094-095.
IA...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR IAZ008-009-018-019.
&&
$$
SHORT TERM...AJ
LONG TERM...ZT
AVIATION.......RIECK
CLIMATE........BOYNE
FIRE WEATHER...WETENKAMP/AJ
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
315 PM CDT TUE SEP 11 2012
...UPDATED SHORT TERM SECTION...
.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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 104 PM CDT TUE SEP 11 2012
VFR SKY CONDITIONS ARE EXPECTED TO CONTINUE THROUGH MIDDAY
WEDNESDAY...SO WINDS WILL BE THE PRIMARY AVIATION INTEREST. FOR THE
REMAINDER OF THIS AFTERNOON...25 KNOT WINDS CAN BE EXPECTED FROM THE
SOUTH WITH SOME GUSTS IN THE 30-35 KNOT RANGE. AFTER SUNSET...WINDS
WILL DECREASE SOME...BUT 20 KNOTS SUSTAINED WILL LIKELY PERSIST
THROUGH A GOOD PORTION OF THE NIGHT. AN INTENSE LOW LEVEL JET WILL
DEVELOP AND PEAK AROUND 2000 FEET ABOVE GROUND LEVEL AT 55 TO 60
KNOTS...SO WILL GO AHEAD AND CONTINUE THE INCLUSION OF A WS GROUP
FOR DDC AND HYS TERMINALS. WINDS WILL DECREASE TO 10 TO 15 KNOTS 12
TO 18Z AS GRADIENT RELAXES SOME PRIOR TO STRONG COLD FRONT PASSAGE
AROUND MIDDAY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 67 92 55 65 / 10 20 80 80
GCK 64 86 52 67 / 10 20 80 60
EHA 65 84 52 66 / 10 20 80 70
LBL 66 90 53 66 / 10 20 70 70
HYS 67 87 53 67 / 10 10 70 50
P28 70 97 63 65 / 10 20 70 80
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ030-031-
043>046-063>066-075>081-085>090.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
243 PM CDT TUE SEP 11 2012
...UPDATE TO LONG TERM...
.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...(TODAY THROUGH TONIGHT)
ISSUED AT 144 AM CDT TUE SEP 11 2012
THE SURFACE LOW PRESSURE SYSTEM OVER EASTERN COLORADO WILL DEEPEN
DURING THE DAY TODAY, CAUSING WARM AIR TO RIDE NORTH-NORTHEAST ACROSS
WESTERN KANSAS. WINDS WILL BE SOUTH TODAY, INCREASING INTO THE 15
TO 25 MPH GUSTING TO 35 MPH RANGE THIS AFTERNOON. THE BIGGEST WEATHER
DECISION TODAY IS DEW POINTS. THINK WITH WHAT HAPPENED YESTERDAY
WITH DRIER AIR MIXING DOWN AFTER THE STRONG WINDS KICKED IN, HAVE
DECIDED TO ISSUE A RED FLAG WARNING FOR ABOUT OUR EASTERN HALF OF
THE CWA, FROM 2PM TO 8PM CDT. THE WINDS WILL BE STRONGEST THERE,
THESE STRONG WINDS WILL HELP MIX DOWN DRIER AIR, AND RELATIVE
HUMIDITIES SHOULD DIP TO THE 14-16 PERCENT RANGE DURING THE AFTERNOON.
IN OUR WESTERN CWA, DUE TO THE PROXIMITY TO THE EASTERN COLORADO
LOW, WINDS WILL NOT BE AS STRONG AS THEY WILL BE IN THE EAST, AND
DEW POINTS SHOULD DIP AS MUCH BECAUSE OF LESS DOWNWARD MIXING.
MAX TEMPERATURES TODAY WILL PEAK IN THE MID 90S MOST PLACES, THE
WARMEST IN OUR SOUTHWESTERN CORNER. WINDS WILL BE SLOW TO ABATE
TONIGHT, WITH THE COLORADO LOW MOVING INTO WESTERN KANSAS. WINDS
MAY NOT DROP TO LESS THAN 20 MPH UNTIL AFTER 06Z, AND THEN ONLY TO
10 TO 12 MPH. WITH CLEAR SKIES, BUT THE PERSISTENT WINDS, MIN
TEMPERATURES WILL ONLY DROP TO MID TO UPPER 60S. AT THIS TIME,
STILL THINK PRECIP WILL HOLD OFF UNTIL AFTER MY TUESDAY 12Z TIME
FRAME. ALL SHORT TERM MODEL CONCUR ON NO PRECIP IN OUR CWA UNTIL
AFTER 12Z TUESDAY.
.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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 104 PM CDT TUE SEP 11 2012
VFR SKY CONDITIONS ARE EXPECTED TO CONTINUE THROUGH MIDDAY
WEDNESDAY...SO WINDS WILL BE THE PRIMARY AVIATION INTEREST. FOR THE
REMAINDER OF THIS AFTERNOON...25 KNOT WINDS CAN BE EXPECTED FROM THE
SOUTH WITH SOME GUSTS IN THE 30-35 KNOT RANGE. AFTER SUNSET...WINDS
WILL DECREASE SOME...BUT 20 KNOTS SUSTAINED WILL LIKELY PERSIST
THROUGH A GOOD PORTION OF THE NIGHT. AN INTENSE LOW LEVEL JET WILL
DEVELOP AND PEAK AROUND 2000 FEET ABOVE GROUND LEVEL AT 55 TO 60
KNOTS...SO WILL GO AHEAD AND CONTINUE THE INCLUSION OF A WS GROUP
FOR DDC AND HYS TERMINALS. WINDS WILL DECREASE TO 10 TO 15 KNOTS 12
TO 18Z AS GRADIENT RELAXES SOME PRIOR TO STRONG COLD FRONT PASSAGE
AROUND MIDDAY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 67 94 55 65 / 10 20 80 80
GCK 64 89 52 67 / 10 20 80 60
EHA 65 87 52 66 / 10 20 80 70
LBL 66 93 53 66 / 10 20 70 70
HYS 66 88 53 67 / 10 10 70 50
P28 67 95 63 65 / 10 20 70 80
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ030-031-
043>046-063>066-075>081-085>090.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
106 PM CDT TUE SEP 11 2012
...UPDATED SYNOPSIS AND AVIATION SECTIONS...
.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...(TODAY THROUGH TONIGHT)
ISSUED AT 144 AM CDT TUE SEP 11 2012
THE SURFACE LOW PRESSURE SYSTEM OVER EASTERN COLORADO WILL DEEPEN
DURING THE DAY TODAY, CAUSING WARM AIR TO RIDE NORTH-NORTHEAST ACROSS
WESTERN KANSAS. WINDS WILL BE SOUTH TODAY, INCREASING INTO THE 15
TO 25 MPH GUSTING TO 35 MPH RANGE THIS AFTERNOON. THE BIGGEST WEATHER
DECISION TODAY IS DEW POINTS. THINK WITH WHAT HAPPENED YESTERDAY
WITH DRIER AIR MIXING DOWN AFTER THE STRONG WINDS KICKED IN, HAVE
DECIDED TO ISSUE A RED FLAG WARNING FOR ABOUT OUR EASTERN HALF OF
THE CWA, FROM 2PM TO 8PM CDT. THE WINDS WILL BE STRONGEST THERE,
THESE STRONG WINDS WILL HELP MIX DOWN DRIER AIR, AND RELATIVE
HUMIDITIES SHOULD DIP TO THE 14-16 PERCENT RANGE DURING THE AFTERNOON.
IN OUR WESTERN CWA, DUE TO THE PROXIMITY TO THE EASTERN COLORADO
LOW, WINDS WILL NOT BE AS STRONG AS THEY WILL BE IN THE EAST, AND
DEW POINTS SHOULD DIP AS MUCH BECAUSE OF LESS DOWNWARD MIXING.
MAX TEMPERATURES TODAY WILL PEAK IN THE MID 90S MOST PLACES, THE
WARMEST IN OUR SOUTHWESTERN CORNER. WINDS WILL BE SLOW TO ABATE
TONIGHT, WITH THE COLORADO LOW MOVING INTO WESTERN KANSAS. WINDS
MAY NOT DROP TO LESS THAN 20 MPH UNTIL AFTER 06Z, AND THEN ONLY TO
10 TO 12 MPH. WITH CLEAR SKIES, BUT THE PERSISTENT WINDS, MIN
TEMPERATURES WILL ONLY DROP TO MID TO UPPER 60S. AT THIS TIME,
STILL THINK PRECIP WILL HOLD OFF UNTIL AFTER MY TUESDAY 12Z TIME
FRAME. ALL SHORT TERM MODEL CONCUR ON NO PRECIP IN OUR CWA UNTIL
AFTER 12Z TUESDAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 415 AM CDT TUE SEP 11 2012
THE MEDIUM RANGE MODELS CONTINUE TO SHOW A STRONG WAVE MOVING ACROSS
SOUTHERN CANADA AND THE NORTHERN TIER OF STATES TUESDAY NIGHT AND
WEDNESDAY WITH A SECONDARY TROUGH DEVELOPING ACROSS THE NORTHERN
PLAINS WEDNESDAY AND PUSHING SOUTHEAST THROUGH THE MIDWEST AND
CENTRAL PLAINS ON THURSDAY. THE MEDIUM RANGE MODELS ARE COMING INTO
MUCH BETTER AGREEMENT REGARDING THE STRENGTH AND TIMING OF THIS
SYSTEM. THE ASSOCIATED SURFACE COLD FRONT IS FORECAST TO MOVE SLOWLY
INTO WEST CENTRAL AND NORTHWEST KANSAS DURING THE MORNING HOURS
WEDNESDAY BEFORE ACCELERATING SOUTHEAST LATER IN THE DAY WITH THE
APPROACH OF THE DIGGING UPPER WAVE. THROUGH WEDNESDAY NIGHT AND
THURSDAY THE UPPER WAVE MOVES INTO THE REGION. AHEAD OF THE WAVE
THERE WILL BE A FAIRLY SIGNIFICANT UPPER LEVEL JET EXTENDING FROM
THE CENTRAL HIGH PLAINS INTO THE WESTERN GREAT LAKES. MUCH OF THE
REGION WILL BE UNDER THE RIGHT ENTRANCE REGION OF THIS JET WEDNESDAY
NIGHT INTO THURSDAY MORNING.
THE BEST CHANCES FOR PRECIPITATION ACROSS WESTERN KANSAS WILL BE
LATE WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING AS THE MID LEVELS
OF THE ATMOSPHERE COOL AND MOISTEN UP IN RESPONSE TO THE APPROACHING
WAVE. MODEL SOUNDINGS SHOW SOME WEAK INSTABILITY WEDNESDAY AFTERNOON
WITH ONLY A FEW HUNDRED J/KG OF CAPE. THIS SHOULD SUPPORT A FEW
THUNDERSTORMS ALONG THE FRONT. PRECIPITATION CHANCES WILL BE
INCREASING CONSIDERABLY WEDNESDAY NIGHT GIVEN THE SATURATED SOUNDING
PROFILE AND UPWARD VERTICAL MOTION ASSOCIATED WITH THE WAVE AND
UPPER JET. HAVE BUMPED UP POPS TO NEAR 80 PERCENT DURING THE
WEDNESDAY NIGHT THROUGH THURSDAY MORNING TIME PERIOD. ALONG WITH
SURROUNDING WFOS...HAVE ALSO BUMPED UP THE QPF VALUES THROUGH THIS
TIME PERIOD CLOSER TO THE HPC FORECAST.
PRECIPITATION CHANCES WILL BE DIMINISHING FROM NORTHWEST TO
SOUTHEAST ON THURSDAY AS THE UPPER WAVE MOVES BY. THINK THAT BY
THURSDAY EVENING ONLY SLIGHT CHANCE POPS WILL BE WARRANTED OVER
SOUTH CENTRAL KANSAS WITH CHANCES ENDING AFTER MIDNIGHT.
SOUTHWEST KANSAS WILL SEE A FEW MILD AND DRY DAYS INTO THE WEEKEND
AS UPPER LEVEL SHORTWAVE RIDGING MOVES OVER THE CENTRAL HIGH PLAINS.
ANOTHER STRONG SHORTWAVE TROUGH IS PROGGED BY THE MODELS TO DIVE
INTO THE MIDWEST AND PLAINS NEXT MONDAY. THE MODELS SHOW WIDELY
VARYING SOLUTIONS AS TO HOW THIS PANS OUT. FOR NOW WILL LEAVE THE
ALLBLEND FORECAST AS IS WHICH HAS SMALL POPS OVER WEST CENTRAL
KANSAS ON MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 104 PM CDT TUE SEP 11 2012
VFR SKY CONDITIONS ARE EXPECTED TO CONTINUE THROUGH MIDDAY
WEDNESDAY...SO WINDS WILL BE THE PRIMARY AVIATION INTEREST. FOR THE
REMAINDER OF THIS AFTERNOON...25 KNOT WINDS CAN BE EXPECTED FROM THE
SOUTH WITH SOME GUSTS IN THE 30-35 KNOT RANGE. AFTER SUNSET...WINDS
WILL DECREASE SOME...BUT 20 KNOTS SUSTAINED WILL LIKELY PERSIST
THROUGH A GOOD PORTION OF THE NIGHT. AN INTENSE LOW LEVEL JET WILL
DEVELOP AND PEAK AROUND 2000 FEET ABOVE GROUND LEVEL AT 55 TO 60
KNOTS...SO WILL GO AHEAD AND CONTINUE THE INCLUSION OF A WS GROUP
FOR DDC AND HYS TERMINALS. WINDS WILL DECREASE TO 10 TO 15 KNOTS 12
TO 18Z AS GRADIENT RELAXES SOME PRIOR TO STRONG COLD FRONT PASSAGE
AROUND MIDDAY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 67 94 55 66 / 10 20 80 70
GCK 64 89 52 65 / 10 30 80 60
EHA 65 87 52 65 / 10 40 80 60
LBL 66 93 53 66 / 10 20 80 60
HYS 66 88 53 65 / 10 20 80 60
P28 67 95 63 70 / 10 10 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR KSZ030-031-
043>046-063>066-075>081-085>090.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...BURKE
LONG TERM...GERARD
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
313 PM EDT TUE SEP 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR A DRY WEEK WITH TEMPERATURES WARMING
EACH DAY. A COLD FRONT WILL CROSS THE AREA LATE IN THE WEEK INTO
THE EARLY WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THAT THE UPPER OHIO
VALLEY IS ON THE NORTHEASTERN PERIPHERY OF A BROAD 500MB TROUGH
CENTERED ACROSS THE MISSOURI VALLEY AND THE GULF STATES. AT THE
SURFACE, A 1028MB HIGH IS CENTERED ACROSS WEST VIRGINIA AND IS
DOMINATING THE WEATHER PATTERN ACROSS THE EASTERN US WITH CLEAR
SKIES.
HIGH PRESSURE AND A DEEP LAYER OF DRY AIR ALOFT WILL CONTINUE TO
DOMINATE THE PATTERN THROUGH TONIGHT. ASIDE FROM LITTLE CIRRUS
PASSING NORTH OF THE AREA, SKIES WILL BE CLEAR WITH LIGHT
SOUTHERLY WINDS. TEMPS WILL RECOVER QUICKLY TODAY WITH HIGHS
CLOSE TO A MAV/MET BLEND IN THE MID 70S ACROSS MOST OF THE AREA.
ANOTHER NIGHT OF RADIATIONAL COOLING WITH PATCHY RIVER VALLEY FOG
CAN BE EXPECTED TONIGHT WITH LOWS AROUND 5 TO 10 DEGREES BELOW
SEASONAL NORMALS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
A MODEL CONSENSUS INDICATES THAT THE MID-LEVEL RIDGE WILL BUILD
INTO THE UPPER OHIO VALLEY ON WEDNESDAY AND THEN AMPLIFY FURTHER
INTO THE NORTHEAST ON THURSDAY AND FRIDAY. THIS WILL ALLOW FOR
BENIGN WEATHER TO CONTINUE, WITH CLEAR SKIES ASIDE FROM OCCASIONAL
PASSING CIRRUS.
TEMPERATURES THROUGH THIS PERIOD WILL BE INCREASINGLY WARMER
WEDNESDAY INTO THURSDAY WITH WARM AIR ADVECTION IN A SOUTHWESTERLY
FLOW. HIGHS WEDNESDAY WILL BE AROUND 5 DEGREES ABOVE NORMAL,
MODERATING TO 10 DEGREES ABOVE NORMAL ON THURSDAY. ON FRIDAY,
DESPITE INCREASING CLOUD COVERAGE AHEAD OF A COLD FRONT, ENHANCED
WARM AIR ADVECTION AHEAD OF THE FRONT WILL ALLOW TEMPS TO WARM TO
5 TO 10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SOME UNCERTAINTY ENTERS THE FORECAST ON FRIDAY NIGHT AS A MID-
LEVEL TROUGH ACROSS THE UPPER MIDWEST CLOSED OFF INTO A LOW OVER
THE GREAT LAKES AND SWEEPS A COLD FRONT ACROSS THE REGION. THE 12Z
GFS IS FASTER WITH THE FRONTAL PASSAGE (FRIDAY NIGHT) THAN THE
ECMWF/CANADIAN SOLUTIONS (SATURDAY). HAVE TRENDED EARLIER WITH THE
FRONTAL PASSAGE FRIDAY NIGHT INTO EARLY SATURDAY, WITH CHANCE POPS
AND SCHC THUNDER.
THE CLOSED LOW WILL PUSH INTO THE NORTHEAST ON SUNDAY, LEAVING THE
UPPER OHIO VALLEY IN A NORTHWESTERLY FLOW. EARLY NEXT WEEK,
UNCERTAINTY INCREASES AS MODELS DIVERGE AND THUS FORECAST IS
CLOSE TO HPC. TEMPS WILL BE NEAR NORMAL SEASONAL VALUES THROUGH
THE EXTENDED PERIOD.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL PROVIDE FOR VFR CONDITIONS AND LIGHT WINDS
THROUGH THE TAF PERIOD. A BRIEF PERIOD OF VISIBILITY RESTRICTIONS
WILL BE POSSIBLE WITH RIVER VALLEY FOG NEAR DAWN AT KAGC.
.OUTLOOK /WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL MAINTAIN VFR CONDITIONS THROUGH FRIDAY WITH
ONLY BRIEF RESTRICTIONS IN VALLEY FOG POSSIBLE IN THE MORNING EACH
DAY. A FRONT APPROACHING FOR THE WEEKEND COULD POTENTIALLY BRING
SHOWERS FRIDAY NIGHT INTO SATURDAY. VFR CONDITIONS WILL RETURN IN
THE WAKE OF THE FRONT ON SUNDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
109 PM EDT TUE SEP 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY WEATHER WITH WARMING TEMPERATURES
EACH DAY THIS WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO MAKE
SLIGHT ADJUSTMENT TO SKY GRIDS AS CIRRUS CROSSES PORTIONS OF THE
AREA. THE REST OF THE PREVIOUS DISCUSSION REMAINS THE SAME.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THAT THE UPPER OHIO
VALLEY IS ON THE NORTHEASTERN PERIPHERY OF A BROAD 500MB TROUGH
CENTERED ACROSS THE MISSOURI VALLEY AND THE GULF STATES. AT THE
SURFACE, A 1028MB HIGH IS CENTERED ACROSS WEST VIRGINIA AND IS
DOMINATING THE WEATHER PATTERN ACROSS THE EASTERN US WITH CLEAR
SKIES.
HIGH PRESSURE AND A DEEP LAYER OF DRY AIR ALOFT WILL CONTINUE TO
DOMINATE THE PATTERN THROUGH TONIGHT. ASIDE FROM LITTLE CIRRUS
PASSING NORTH OF THE AREA, SKIES WILL BE CLEAR WITH LIGHT
SOUTHERLY WINDS. TEMPS WILL RECOVER QUICKLY TODAY WITH HIGHS
CLOSE TO A MAV/MET BLEND IN THE MID 70S ACROSS MOST OF THE AREA.
ANOTHER NIGHT OF RADIATIONAL COOLING WITH PATCHY RIVER VALLEY FOG
CAN BE EXPECTED TONIGHT WITH LOWS AROUND 5 TO 10 DEGREES BELOW
SEASONAL NORMALS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
MIDWRN RIDGE ALOFT IS FORECAST TO SHIFT EWD AND AMPLIFY IN RESPONSE
TO CUTOFF LOW DIGGING ACRS WRN CANADA. WITH THE SFC HIGHS EWD
SHIFT...WARM ADVCTN WL RESUME UNDR THE SBSDNC REGIME/RISING HTS
ALOFT. TEMP MODERATION MAY THUS BE ANTICIPATED WITH AFTN HIGHS
RISING TO APPROX 5 DEGREES ABOVE THE SEASONAL AVERAGES.
STRNG RADIATIONAL COOLING WL AGAIN SPPRT SUB NORMAL LOWS ON
WEDNESDAY MRNG...BUT NR AVG READINGS ARE ANTICIPATED FOR THURSDAY
AND FRIDAY MRNG AS THE BNDRY LYR MSTR SLOWLY RISES. OVERALL TEMP
FORECAST WAS BASED ON PERSISTENCE WITH A TWEAK BASED ON RECENT GFS
AND NAM MOS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
ALTHOUGH MDLS RMN IN GENL AGRMNT THAT A CDFTN WL MOV ACRS THE UPR
OH VALLEY OVR THE WEEKEND...TIMING IS QNABLE AS IS NORMAL AT THIS
POINT IN THE FORECAST CYCLE. THE GFS CONTS TO BE THE FASTER
SOLN...WITH THE FRONT AFFECTING THE REGION SATURDAY/SATURDAY
NIGHT. AS THE ENSEMBLE MEAN LEANS MORE TWDS A SATURDAY NGT/SUNDAY
PASSAGE...HAVE GONE WITH THIS SCENARIO. HIGH PRES IS THEN FORECAST
TO SLIDE OVR THE AREA BY SUNDAY.
TEMPS WERE FORECASTED ABOVE THE AVERAGES FOR FRIDAY...THEN DROPPED TO
NR SEASONAL READINGS IN THE WAKE OF THE FRONT.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL PROVIDE FOR VFR CONDITIONS AND LIGHT WINDS
THROUGH THE TAF PERIOD.
.OUTLOOK /WEDNESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL MAINTAIN VFR CONDITIONS THROUGH FRIDAY WITH
ONLY BRIEF RESTRICTIONS IN VALLEY FOG POSSIBLE IN THE MORNING EACH
DAY. A FRONT APPROACHING FOR THE WEEKEND COULD POTENTIALLY BRING
SHOWERS ON SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
231 PM CDT TUE SEP 11 2012
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
MOVING NORTHEAST ALONG THE NORTH DAKOTA-MINNESOTA BORDER WHILE HIGH
PRESSURE IS SITUATED OVER THE APPALACHIANS. AHEAD OF THE FRONT...A
FEW SPOTTY SHOWERS ARE PRESENT OVER CENTRAL MINNESOTA AND MID AND
HIGH CLOUDS ARE ADVANCING INTO NORTHWEST WISCONSIN. 12Z SOUNDINGS
INDICATE A VERY DRY AIRMASS AHEAD OF THE FRONT IN THE LOW LEVELS
WHERE DEWPOINT DEPRESSIONS ARE IN THE UPPER TEENS TO LOWER 20S AT
850MB. AS THE FRONT MOVES ACROSS THE REGION LATE TONIGHT INTO
WEDNESDAY...LIGHT SHOWER POTENTIAL IS THE MAIN FORECAST CONCERN.
TONIGHT...THE COLD FRONT OVER THE NORTHERN MISSISSIPPI VALLEY WILL
MOVE INTO NORTH-CENTRAL WISCONSIN LATE TONIGHT. STILL NO MOISTURE
AHEAD OF THE FRONT AS DEWPOINTS ARE ONLY IN THE 40S TO LOW 50S OVER
THE PLAINS. INSTEAD WILL SEE SCT TO BKN MID AND HIGH CLOUDS
ASSOCIATED WITH THE FRONTAL ZONE PUSH ACROSS NORTHWEST INTO CENTRAL
WISCONSIN AFTER MIDNIGHT. ELSEWHERE...WILL SEE MOSTLY CLEAR
CONDITIONS WITH A WARM SOUTHWEST WIND. LOWS RANGING FROM THE UPPER
50S NORTH TO THE MIDDLE 60S NEAR LAKE MICHIGAN.
WEDNESDAY...THE FRONT WILL CONTINUE TO SLOWLY MOVE TO THE SOUTHEAST
ACROSS NORTHEAST WISCONSIN DURING THE MORNING AND EAST-CENTRAL
WISCONSIN DURING THE AFTERNOON. AS MID-LEVEL HEIGHT FALLS OCCUR...
A BKN MID-LEVEL CLOUD DECK WILL BE IN PLACE ACROSS THE NORTHWEST
HALF OF THE FORECAST AREA FOR MUCH OF THE DAY. MID-LEVEL FGEN WILL
WORK ITS WAY SOUTHEAST ACROSS NORTHEAST AND CENTRAL WISCONSIN...BUT
CLOUD BASES WILL BE NEAR OR ABOVE 10 KFT ACCORDING TO PROGGED
SOUNDINGS. LOW LEVELS WILL REMAIN DRY...SO THINK IT WILL BE TOUGH
FOR ANY LIGHT SHOWERS TO MEASURE AT THE SURFACE. BUT MODELS ARE
INSISTENT ON SPITTING OUT LIGHT QPF AND INHERITED FORECAST CALLS FOR
A LOW CHANCE OF SHOWERS. SO WILL KEEP A MENTION OF SLIGHT CHANCE OF
SHOWERS IN THE FORECAST. HIGHS WILL BE COOLER OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN BEHIND THE FRONT AND BENEATH CLOUD COVER.
WILL GO WITH TEMPS RANGING FROM NEAR 70 NORTHWEST TO THE LOWER 80S
SOUTHEAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY...PCPN TRENDS FOR
THE END OF THE WORK WEEK/BEGINNING OF THE WEEKEND...AND TEMPS...
ARE THE MAIN FCST CONCERNS.
MODELS STILL TRYING TO SETTLE ON A SOLUTION FOR THE END OF THE
WEEK...BUT THE GENERAL TREND HAS BEEN TO SPEED UP THE PASSAGE OF
THE POST-FRONTAL PCPN BAND DURING THE WEDS NGT-THU NGT PERIOD.
EVEN THE DEEP AND POSSIBLY CLOSED-OFF UPPER SYSTEM IS EXPECTED TO
SWING THROUGH FAIRLY QUICKLY ON FRIDAY. HAVE ADJUSTED POPS
ACCORDINGLY...BUT DID BLEND A BIT WITH THE SLIGHTLY SLOWER 00Z
ECMWF RUN FOR BETTER CONSISTENCY AND THE POSSIBILITY THAT THE
NEW RUNS ARE TOO FAST. HIGHEST POPS OCCUR WEDS NGT/THU...AND
LINGER IN OUR SE COUNTIES INTO THU NGT. CHC POPS ARE STILL
WARRANTED FOR EASTERN WI FRI INTO FRI NGT...UNTIL THE UPPER
LOW SHIFTS EAST. COOLER MAX TEMPS IN THE 60S ARE EXPECTED ON
THU/FRI.
THE WEEKEND IS LOOKING NICE...WITH WEAK HIGH PRESSURE OVER THE
REGION. HIGH TEMPS SHOULD WARM BACK TO ABOVE NORMAL BY SUNDAY.
THE NEXT FRONTAL SYSTEM IS EXPECTED TO MOVE THROUGH THE AREA
SOMETIME DURING THE MON-TUES TIME FRAME. THE TIMING OF THE
FRONT IS IN QUESTION...SO ONLY SLGT CHC/CHC POPS WILL BE
INCLUDED DURING THE PERIOD FOR NOW.
&&
.AVIATION...COLD FRONT OVER THE NORTHERN PLAINS WILL SLOWLY MOVE
EAST INTO CENTRAL WISCONSIN LATE TONIGHT INTO NORTHEAST WISCONSIN
WEDNESDAY MORNING. EXPECTING THIS FRONT TO MOVE THROUGH
DRY...THOUGH MODELS ARE TRYING TO SPIT OUT LIGHT SHOWERS ON
WEDNESDAY. FORECAST SOUNDINGS INDICATE CLOUD BASES ONLY FALLING TO
AROUND 10 KFT...SO IF ANY SHOWERS FORM...THEY WILL BE LIGHT.
OTHERWISE...LOW LEVEL WIND SHEAR WILL CRANK UP AGAIN TONIGHT. AS
THE FRONT MOVES IN HOWEVER...A LOOSENING PRESSURE GRADIENT WILL
CAUSE THE WIND SHEAR TO DIMINISH. IN GENERAL...VFR CONDITIONS OVER
THE TAF PERIOD.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TSK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1233 PM CDT TUE SEP 11 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
319 AM CDT TUE SEP 11 2012
MAIN FORECAST CONCERNS ARE ON FIRE WEATHER TODAY...THEN
PRECIPITATION CHANCES AND TRENDS WEDNESDAY THROUGH THURSDAY NIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED DEEP TROUGHING OVER SOUTHWEST CANADA INTO THE PACIFIC
NORTHWEST AND RIDGING DOWNSTREAM FROM THE CENTRAL PLAINS INTO THE
WESTERN GREAT LAKES REGION. SHORTWAVES OF NOTE INCLUDE ONE OVER
NORTHWEST SOUTH DAKOTA...THEN A COMPLEX OF THEM IN THE MONSOONAL
MOISTURE ACROSS THE DESERT SOUTHWEST. ASSOCIATED WITH THE SOUTH
DAKOTA SHORTWAVE IS A SURFACE LOW JUST NORTH OF PIERRE. A TIGHT
PRESSURE GRADIENT EXISTS AHEAD OF THIS LOW INTO THE FORECAST
AREA...RESULTING IN BREEZY SOUTH WINDS. THESE WINDS HAVE KEPT
TEMPERATURES UP IN THE MID 50S TO MID 60S. HIGHER ALOFT...AT
850MB...PROFILER DATA SHOWED A SOUTHWEST 35-50 KT JET EXTENDING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA...ADVECTING WARM
AIR NORTHEASTWARD. 850MB TEMPS HAVE CLIMBED TO 18-22C PER RAP
ANALYSIS...COMPARED TO 00Z RAOBS WHICH WERE BETWEEN 16-18C.
AIRMASS ALSO REMAINS QUITE DRY ACROSS THE CENTRAL PLAINS INTO THE
FORECAST AREA...NOTED BY GOES SOUNDER PRECIPITABLE WATER VALUES OF
0.5-0.6 INCHES OR 60 PERCENT OF NORMAL. ALSO REFLECTIVE OF THE DRY
AIR WAS THE 00Z MPX SOUNDING WHICH HAD DEWPOINT DEPRESSIONS OF 15C
OR MORE FROM THE SURFACE TO 350MB. THE 00Z OAX SOUNDING WAS EVEN
DRIER. SATELLITE IMAGERY DEPICTING ONLY A LITTLE CIRRUS OVER THE
FORECAST AREA.
TODAY AND TONIGHT...MODELS TAKE THE DEEP SOUTHWEST CANADA TROUGH
EASTWARD INTO SOUTH CENTRAL CANADA BY 12Z WEDNESDAY. AS THIS TROUGH
PUSHES EAST...IT WILL PICK UP THE SHORTWAVE AND SURFACE LOW IN SOUTH
DAKOTA...LIFTING THEM INTO NORTHERN ONTARIO. THE ASSOCIATED COLD
FRONT IS TRENDING SLIGHTLY FASTER...NOW PROGGED TO REACH AROUND LA
CROSSE WI AT 12Z WEDNESDAY. THE WARM AIR SURGE AHEAD OF THE FRONT
CONTINUES TODAY WITH 850MB TEMPS PROGGED TO TOP OUT AT 20-22C FOR
18Z. THESE ARE NEAR 2 STANDARD DEVIATIONS ABOVE NORMAL. PLENTY OF
DRY AIR REMAINS...AND WITH 925MB SOUTHWEST WINDS OF 25-30 KT
PROMOTING MIXING AS WELL AS PLENTY OF SUN OUTSIDE OF SOME CIRRUS
LATE IN THE DAY...SHOULD HAVE NO PROBLEM MIXING UP TO THOSE 850MB
TEMPS. THUS...ANTICIPATING HIGHS SIMILAR TO THE PREVIOUS
FORECASTS...FROM THE MID 80S TO LOW 90S. GIVEN THE DRY AIR...BREEZY
CONDITIONS AND WARM TEMPERATURES...CRITICAL FIRE WEATHER CONDITIONS
ARE LIKELY. SEE FIRE WEATHER DISCUSSION FOR MORE DETAILS. FOR
TONIGHT...ALTHOUGH THE FRONT IS MOVING IN SLIGHTLY FASTER...ALL THE
FRONTOGENETIC FORCING AND MOISTURE STILL REMAINS NORTHWEST OF THE
FORECAST AREA. THEREFORE...EXPECTING DRY CONDITIONS AND ONLY A
GRADUAL INCREASE IN CLOUDS. WARM NIGHT ON TAP GIVEN WARM START
AND BREEZY WINDS AHEAD OF THE FRONT. MOST LOCATIONS SHOULD SEE LOWS
IN THE 60S.
WEDNESDAY AND WEDNESDAY NIGHT...ON THE WEST SIDE OF THE DEEP
SOUTHWEST CANADA TROUGH...MODELS ARE IN GOOD AGREEMENT DROPPING A
POTENT SHORTWAVE DOWN INTO THE NORTHERN PLAINS BY 12Z THURSDAY. THIS
SHORTWAVE LOOKS TO HELP KICK OUT ALL OF THE MONSOONAL SHORTWAVES...
EJECTING THEM NORTHEAST ACROSS THE FORECAST AREA. IT APPEARS A
COMBINATION OF THESE VARIOUS SHORTWAVES...ALONG WITH THE POTENT
SHORTWAVE TROUGH...WILL HELP TO KEEP THE COLD FRONT THAT IS NEAR LA
CROSSE AT 12Z WEDNESDAY MOVING TO THE EAST. OF INTEREST...THOUGH...
IS THE FORCING BEHIND THIS COLD FRONT. MODELS DEPICT AN 80-120 KT
JET AT THE TROPOPAUSE PERSISTING BOTH WEDNESDAY AND WEDNESDAY NIGHT
FROM CENTRAL MINNESOTA INTO NORTHERN ONTARIO...PLACING THE FORECAST
AREA IN THE RIGHT ENTRANCE REGION FOR UPPER LEVEL DIVERGENCE. LOWER
IN THE TROPOSPHERE...PLENTY OF LOW TO MID LEVEL FRONTOGENESIS
EXISTS...THOUGH THERE ARE SOME DIFFERENCES IN THE STRENGTH. FOR
EXAMPLE...THE 11.00Z NAM/REGIONAL CANADIAN ARE QUITE A BIT WEAKER
THAN THE 11.00Z GFS/UKMET AND AS SUCH IS A LOT LIGHTER WHEN IT COMES
TO ITS QPF FORECAST. IN FACT...THE 11.00Z NAM DEPICTS VERY LITTLE
RAIN FOR LOCATIONS NORTH OF I-90. CERTAINLY PLENTY OF MOISTURE
EXISTS WITH BOTH THE 11.00Z NAM AND GFS SHOWING AN AXIS OF 1-1.4
INCHES OF PRECIPITABLE WATER WHERE THE FRONTOGENESIS IS. GIVEN ALL
THE FORCING...WOULD HAVE TO THINK A WETTER SOLUTION IS MORE LIKELY.
SREF PROBABILITIES DEPICTING SOME SIMILAR UNCERTAINTY WITH HIGHER
PROBABILITIES OF PRECIPITATION SOUTH OF I-90. WILL TAILOR FORECAST
THIS WAY UNTIL MODELS CAN GET INTO BETTER AGREEMENT. DID REMOVE
THUNDER AS LAPSE RATES UNDER THE FRONTOGENETICAL BAND ARE MAINLY
MOIST-ADIABATIC. THERE IS SOME NEGATIVE EPV RESULTING FROM SLANTWISE
INSTABILITY...SO A COUPLE LIGHTNING STRIKES CANNOT BE RULED OUT.
HOWEVER...MENTIONING ISOLATED THUNDER FOR A WIDESPREAD AREA SEEMS
TOO HIGH OF A PROBABILITY. TEMPERATURES ARE QUITE TRICKY...SINCE
WHERE IT RAINS READINGS WILL BE HELD DOWN DUE TO EVAPORATIVE
COOLING. CERTAINLY WITH THE FASTER FRONT AND INCREASING CLOUDS
THROUGH THE DAY WEDNESDAY...HAVE HAD TO COOL HIGHS DOWN. FOR
NOW...HAVE TAKEN A BLEND OF GUIDANCE FOR BOTH HIGHS AND LOWS...WITH
A FALLING TEMP TREND IN THE AFTERNOON FOR THE PRECIPITATION THAT
DEVELOPS.
THURSDAY AND THURSDAY NIGHT...SOME DIFFERENCES EXIST WITH THE
HANDLING OF THE POTENT TROUGH DROPPING INTO THE NORTHERN PLAINS
THURSDAY MORNING. THE 11.00Z NAM IS AN OUTLIER...TAKING THE TROUGH
EAST TO LAKE SUPERIOR THURSDAY NIGHT. ALL OTHER MODELS
(GFS...ECMWF...UKMET...CANADIAN) HAVE THE TROUGH DIGGING DOWN
TOWARDS IOWA AND CLOSING OFF AS AN UPPER LOW. WILL FOLLOW THIS
GROUP...THOUGH EVEN WITHIN THESE THERE ARE ISSUES...MAINLY
PERTAINING TO HOW DEEP THE UPPER LOW BECOMES. FOR EXAMPLE...THE
DEEPEST 11.00Z CANADIAN PRODUCES A WAVE ALONG THE COLD FRONT...
CAUSING A DEFORMATION/FRONTOGENESIS AREA TO PERSIST OVER EASTERN
IOWA INTO THE FORECAST AREA THROUGH THE ENTIRE PERIOD. AS SUCH...THE
CANADIAN KEEPS THE AREA IN MODERATE TO HEAVY RAIN. THERE HAVE BEEN
PAST ECMWF AND GFS RUNS THAT HAVE SUGGESTED THIS SCENARIO...BUT THE
LATEST 11.00Z GFS AND ECMWF SUGGEST THE FRONTOGENESIS ZONE WILL BE
ABLE TO CONTINUE PUSHING EASTWARD AND NEARLY OUT OF THE AREA BY 12Z
FRIDAY. FOR NOW WILL LEAN TOWARDS THE GFS/ECMWF CONSENSUS BEING IN
THE MIDDLE OF THE NAM/CANADIAN EXTREMES...BUT REALIZE THIS PORTION
OF THE FORECAST HAS SOME UNCERTAINTY. ONE THING THAT DOES SEEM SURE
IS THAT THE SOUTHEASTERN HALF OF THE FORECAST AREA WILL SEE RAIN
THURSDAY WITH THE FRONTOGENESIS ZONE IN PLACE THERE BY ALL MODELS.
THUS...PRECIPITATION CHANCES RANGE FROM 70-90 THERE. LOWER CHANCES
OF PRECIPITATION EXIST ELSEWHERE WITH TIMING ISSUES OF THE
FRONTOGENESIS ZONE MOVING OFF. ALTHOUGH MOST MODELS HAVE
PRECIPITATION MOVING OUT OF THE FORECAST AREA THURSDAY NIGHT...
KEEPING AT LEAST A 20 PERCENT CHANCE EVERYWHERE TO ACCOUNT FOR THE
CANADIAN AND PREVIOUS GFS/ECMWF RUNS. MUCH COOLER TEMPERATURES
ANTICIPATED DURING THIS PERIOD...DUE TO A COMBINATION OF COLD
ADVECTION BEHIND THE FRONT KNOCKING 850MB TEMPS DOWN TO 6-8C...AS
WELL AS EVAPORATIVE/DYNAMIC COOLING WHERE IT IS RAINING. POTENTIAL
EXISTS FOR HIGHS ON THURSDAY IN SAY CRAWFORD COUNTY TO NOT GET ABOVE
60.
.LONG TERM...FRIDAY THROUGH MONDAY NIGHT
319 AM CDT TUE SEP 11 2012
FORECAST DURING THIS PERIOD HIGHLY DEPENDENT ON THE EVOLUTION OF THE
UPPER LEVEL LOW THAT IS EXPECTED TO BECOME CLOSED OFF DURING THE DAY
ON FRIDAY SOMEWHERE ACROSS THE UPPER MIDWEST...WITH THE POTENTIAL TO
LINGER INTO THE FIRST PART OF THE UPCOMING WEEKEND. BY 12Z
FRIDAY...SIGNIFICANT MODEL SPREAD IN LOCATION/STRENGTH OF THE UPPER
LEVEL FEATURE. THE 11.00Z GFS WAS MORE PROGRESSIVE WITH THE
SYSTEM...PUSHING IT QUICKLY EASTWARD BY 12Z SATURDAY SUCH THAT THE
FORECAST AREA WOULD BE DRY. MEANWHILE THE 10.12Z ECMWF AND 11.00Z
CANADIAN WERE STRONGER/SLOWER SOLUTIONS...WHICH PIVOTED MORE
ACROSS THE FORECAST AREA. OF NOTE WAS THE 11.00Z CANADIAN WHICH
DEPICTED SEVERAL DEFORMATION RAIN BANDS FRIDAY NIGHT INTO SATURDAY
RESULTING IN A LARGE SWATH OF MODERATE TO HEAVY RAINFALL ACROSS
PORTIONS OF THE AREA. TO ADD TO THE UNCERTAINTY...THE LATEST
11.00Z ECMWF CAME IN MUCH FASTER THAN ALL GUIDANCE AND QUITE
DIFFERENT FROM ITS PREVIOUS RUN. THIS SOLUTION WOULD MEAN MOST OF
FRIDAY INTO THE WEEKEND THE FORECAST AREA WOULD BE DRY WITH NEAR
NORMAL TEMPERATURES. 11.00Z GFS ENSEMBLES REFLECT THE SAME
UNCERTAINTY ON THE UPPER LOW DEPTH/TRACK THAT THE INDIVIDUAL
MODELS SHOW.
GIVEN THE LARGE VARIABILITY IN SOLUTIONS...AND POOR RUN-TO-RUN MODEL
CONSISTENCY...A MODEL CONSENSUS IS APPROPRIATE WHICH KEEPS
HIGHER PRECIPITATIONS CHANCES FRIDAY/FRIDAY NIGHT CONFINED EAST OF
THE MISSISSIPPI RIVER...THEN REDUCES TO JUST 20 PERCENT ON SATURDAY.
REGARDING TEMPERATURES...TRICKY AS WELL...THOUGH FRIDAY LOOKS TO
BE THE COOLEST DAY POTENTIALLY WITH MORE CLOUDS AND HIGHER
PRECIPITATION CHANCES. MODERATING TEMPERATURES TO NEAR NORMAL BY
SUNDAY WITH WEAK NORTHWEST TO NEAR ZONAL FLOW EXPECTED. GOING INTO
EARLY NEXT WEEK...ANOTHER DIGGING UPPER TROUGH WITH SURFACE FRONT
LEADS TO LOW END RAIN CHANCES AND COOLER TEMPERATURES FOR MONDAY
INTO MONDAY NIGHT. PLENTY OF UNCERTAINTY EXISTS TOO ON THIS
DIGGING UPPER TROUGH.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1233 PM CDT TUE SEP 11 2012
MAIN CONCERN IS STRONG WINDS THROUGH THIS AFTERNOON...THEN RAIN
CHANCES LATE IN THE PERIOD. SURFACE MAP EARLY THIS AFTERNOON HAS HIGH
PRESSURE OVER THE OHIO RIVER VALLEY WHILE A COLD FRONT WAS PUSHING
SOUTHEAST ACROSS THE DAKOTAS/CENTRAL PLAINS. PRESSURE GRADIENT AND
DEEP MIXING BETWEEN THESE TWO WEATHER SYSTEMS WILL PRODUCE GUSTY
SOUTH WINDS IN THE 15-25KT RANGE WITH GUSTS 25-35KT. STRONGEST
WINDS EXPECTED ACROSS THE BLUFFTOPS OF SOUTHWEST WISCONSIN AND
HIGHER/OPEN TERRAIN OF SOUTHEAST MN AND NORTHEAST IA. LOOK FOR
THESE WINDS TO SUBSIDE BY SUNSET...THEN SHIFT TO THE NORTHWEST BY
12Z AS THE COLD FRONT PROGRESSES THROUGH THE AREA. EXPECTING
HIGH/MID CLOUDS WITH BASES AOA 12KFT TO BE ON A GRADUAL INCREASE
TONIGHT WITH THE APPROACH OF THE FRONT...THEN LOWERING TO AROUND
8KFT BY 15Z BEHIND THE FRONT. A WAVE OF LOW PRESSURE IS THEN
EXPECTED TO RIDE UP ALONG THIS FRONTAL BOUNDARY AS IT PUSHES
SOUTHEAST ACROSS THE AREA. THIS WILL LIKELY PUSH SOME -SHRA
ACTIVITY INTO THE AREA BY AFTERNOON. MODEL SOUNDING SHOW PRETTY
DRY SUB-CLOUD LAYER THROUGH 18Z...SO OPTED TO KEEP -SHRA MENTION
OUT OF THIS TAF ISSUANCE (THROUGH WED 18Z).
&&
.CLIMATE...TODAY
340 PM CDT SUN SEP 9 2012
HIGH TEMPERATURES WILL CLIMB TO AROUND 90 DEGREES MAINLY NORTHWEST
OF A CHARLES CITY IOWA TO BLACK RIVER FALLS LINE ON TUESDAY. THE
RECORD HIGHS FOR THIS DATE ARE...
LA CROSSE WI - 97 IN 1897
MEDFORD WI - 95 IN 1900
ROCHESTER MN - 94 IN 1931
AUSTIN MN - 92 IN 1948
CHARLES CITY IA - 96 IN 2000
DECORAH IA - 97 IN 1895
&&
.FIRE WEATHER...TODAY
319 AM CDT TUE SEP 11 2012
CRITICAL FIRE WEATHER CONDITIONS REMAIN ON TAP FROM LATE THIS
MORNING THROUGH THIS EVENING ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA. SOUTH TO SOUTHWEST WINDS OF 20 TO 25 MPH WITH
GUSTS OF 30 TO 40 MPH...AND RELATIVE HUMIDITY VALUES OF 20 TO
25 PERCENT ARE EXPECTED...ESPECIALLY DURING THE AFTERNOON HOURS. THE
COMBINATION OF STRONG WINDS AND LOW RH VALUES WILL PRODUCE DANGER
CONDITIONS FOR WILDFIRES. THE RED FLAG WARNING REMAINS IN EFFECT
FROM OLMSTED COUNTY TO CHICKASAW COUNTY WESTWARD. THE WINDS WILL
SUBSIDE LATE TUESDAY EVENING AS A COLD FRONT APPROACHES THE AREA.
HOWEVER...THE COLD FRONT WILL RESULT IN A WIND SHIFT...WITH WINDS
SWITCHING TO THE NORTHWEST. CONDITIONS SHOULD IMPROVE THROUGH THE
NIGHT INTO EARLY WEDNESDAY MORNING AS THE PRESSURE GRADIENT
WEAKENS...TEMPERATURES COOL AND PRECIPITATION EVENTUALLY DEVELOPS.
THROUGH COORDINATION WITH LOCAL FIRE WEATHER PARTNERS
YESTERDAY...LOCATIONS NEAR AND EAST OF THE MISSISSIPPI RIVER HAVE
NOT BEEN INCLUDED IN ANY FIRE WEATHER HEADLINES BECAUSE OF RECENT
RAINS AND FUELS NOT CONDUCIVE TO EXPLOSIVE FIRE GROWTH. SOME DRY
AREAS WILL HAVE TO BE WATCHED CLOSELY...ESPECIALLY SOUTH FACING
SLOPES AND SANDY AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 AM CDT TUE SEP 11 2012
WI...NONE.
MN...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR MNZ086-087-094-095.
IA...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR IAZ008-009-018-019.
&&
$$
SHORT TERM...AJ
LONG TERM...ZT
AVIATION...DAS
CLIMATE........BOYNE
FIRE WEATHER...WETENKAMP/AJ