Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/24/12
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
915 PM PDT TUE AUG 21 2012
.SYNOPSIS...
THE COMBINATION OF MONSOON MOISTURE AND A TROUGH MOVING TOWARDS
CENTRAL CALIFORNIA WILL ALLOW FOR ADDITIONAL SCATTERED SHOWERS AND
THUNDERSTORMS TONIGHT THROUGH WEDNESDAY. THE ASSOCIATED TROUGH WILL
MOVE JUST EAST OF THE REGION ON THURSDAY AND ALLOW FOR DRIER AIR FOR
MOST AREAS. THE MARINE LAYER WILL CONTINUE TO DEEPEN THROUGH
WEDNESDAY AND THEN LINGER INTO THURSDAY. UPPER LEVEL HIGH PRESSURE
WILL REBUILD OVER THE AREA FRIDAY AND SATURDAY WITH DRY CONDITION.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.THIS AFTERNOON AND EVENING...WIDELY SCATTERED STRONG TO SEVERE
THUNDERSTORMS DEVELOPED THIS AFTERNOON ALONG THE SAN DIEGO CREST
AND TRACKED NORTHEAST INTO THE DESERT SLOPES. THE STRONGEST STORM
WAS NEAR MOUNT LAGUNA AND WAS CARRIED INTO THE DESERT SLOPES WHILE
ANOTHER CELL IMPACTED HIGHWAY 78 EAST OF SHELTER VALLEY AND A THIRD
LARGE STORM IN SANTA ROSA MOUNTAINS. ISOLATED THUNDERSTORMS THAT
OCCURRED IN LUCERNE AND JOHNSON VALLEY HAVE REDEVELOPED THIS PAST
HOUR. SPC SURFACE ANALYSIS DEPICTS SBCAPE (INSTABILITY) HAS SHIFTED
TO THE EASTERN AREAS WITH THE WESTERN EDGE OVER LUCERNE VALLEY.
HOWEVER MUCAPE (MOST UNSTABLE) DEPICTS WIDESPREAD 100 TO 500 J/KG
EXTENDING WEST OVER THE COASTAL WATERS. THIS IS DEPICTED IN THE 00Z
UPPER AIR KNKX SOUNDING WITH 1.91 PRECIPITABLE WATER AND SOUTHWEST
FLOW AT 600 TO 500 MB LAYER WHICH WAS STEERING FLOW FOR THE STORMS
TODAY. MOIST LAYER IS ABOUT 800 MB UP TO 500 MB WITH THIS TOPPED
WITH DRY AIR ALOFT. VERY CONDUCIVE TO ELEVATED CONVECTION...GIVEN
SYNOPTIC LIFTING OF THE LAYER TO REACH THE LEVEL OF FREE CONVECTION
AND THE COOL ADIABATIC LAPSE RATE RESPONSE OF THE DRY AIR ALOFT.
THIS PROCESS EXPECTED WHILE THE AIR MASS DECOUPLES OVERNIGHT.
.TONIGHT...WELL DEFINED SHORT WAVE TROUGH APPROACHING POINT
CONCEPTION AND SIGNS OF CLOSING OFF IN THE CORE WITH A PV TAIL
EXTENDING SOUTH TO JUST NORTHWEST OF OUR COASTAL WATER OF SOUTHWEST
CALIFORNIA. AT SUNSET A BAND OF ALTOCUMULUS WAS EVIDENT OVER THE
STRATUS DECK WEST OF PORT CONCEPTION. THE 00Z NAM CONTINUES TO DEPICT
AN AREA OF QVECTOR CONVERGENCE OVER LA COUNTY AND ACROSS MOST
OF OUR FORECAST AREA STARTING NEAR 06Z WHICH SHIFTS EAST AND IS
LINED FROM JOHNSON VALLEY TO THE SAN DIEGO DESERTS BY 12Z. THIS IS
ALSO ALIGNED WITH A WELL DEFINED 700 MB NEAR SATURATED MOISTURE
FIELD WITHIN THE SOUTHERLY FLOW FROM 700 TO 500 MB. SUBSIDENCE
SWEEPS IN QUICKLY FROM WEST TO EAST AFTER 12Z. THEREFORE...GIVEN THE
SYNOPTIC LIFT ENTERING OUR REGION AND THE OBSERVED ELEVATED CAPE IN
PLACE ALONG A DOUBLE AXIS OF PRECIPITABLE WATER (ONE OVER THE
COASTAL WATERS AND ONE OVER FAR SOUTHERN CALIFORNIA) THE THREAT FOR
THE DEVELOPMENT OF ELEVATED MOIST CONVECTION REMAINS. THESE EVENTS
OFTEN DEVELOP QUICKLY AND ARE ALIGNED WITH THE MEAN FLOW ALOFT WHILE
THEY SHIFT EASTWARD AS AN AREA BUT BUILD SOUTHWARD WITH PROPAGATION
ALONG THE CYCLONIC FLOW AND SYNOPTIC LAYER LIFT ALOFT. MODEL
SOUNDINGS HAVE THIS ELEVATED CAPE LAYER SUFFICIENT OVERNIGHT THROUGH
WEDNESDAY MORNING. WE SHOULD SEE CLOUD DEVELOPMENT AND EXPANSION
DURING NEXT COUPLE HOURS OVER SOUTHWEST CALIFORNIA.
PAST SEVERAL RUNS OF THE HRRR MODEL HAVE DEVELOPED SOME CONVECTION
(BUT VARIOUS DEGREE OF COVERAGE) ALONG AND TO THE EAST (MOVING AWAY
IN PREVAILING FLOW) FROM SAN DIEGO COUNTY NORTHWARD INTO WESTERN SAN
BERNARDINO COUNTY.
.WEDNESDAY AND THURSDAY...WHILE MOIST OF THE CONVECTION IS SHUNTED
EAST WITH THE UPPER TROUGH AFTER WEDNESDAY MORNING...THE WESTERN
EDGE OF THE TROPICAL MOISTURE FIELDS REMAINS INTO THE AFTERNOON WITH
THE MAIN SIGNIFICANT COOLING ALOFT. THEREFORE ISOLATED ADDITIONAL
THUNDERSTORMS SHOULD FORM OVER THE HIGH TERRAIN CREST BUT QUICKLY
LIFT EASTWARD ACROSS THE DESERTS DUE TO THE STRONGER SOUTHWEST FLOW
JUST AHEAD OF THE UPPER TROUGH AXIS.
THE SLOW MOVING UPPER TROUGH AXIS SHIFTS EAST OF THE AREA BY THURSDAY
AND UPPER LEVEL FLOW BECOMES NORTHERLY (SOUTHERLY LOWER LEVELS).
MOISTURE DOES LINGER FOR FAR EASTERN AREAS INTO THE LUCERNE AND
JOHNSON VALLEYS SO ISOLATED SHOWERS COULD STILL OCCUR IN THE
BACKSIDE CYCLONIC FLOW OF THE UPPER LOW. OTHERWISE THE DEEP MARINE
LAYER LINGERS BUT BEGINS TO BREAK UP.
.THURSDAY EVENING THROUGH TUESDAY AUGUST 28...CONSENSUS OF MODELS
SHOW HIGH PRESSURE RIDGE REBUILDING ACROSS THE AREA THROUGH SATURDAY
THEN SHIFTING EAST SUNDAY AND MONDAY...THEN THE UPPER RIDGE
FLATTENING ON TUESDAY AS ZONAL FLOW/STORM TRACK DEVELOPS ALONG 40N
LATITUDE. FOR SW CALIFORNIA THIS SHOULD YIELD A WARMING AND DRYING
TREND THROUGH SATURDAY WITH A LOWERING MARINE LAYER...THEN A SLIGHT
COOLING TREND WITH DEEPER MARINE LAYER AND GUSTY SOUTHWEST WINDS FOR
EARLY NEXT WEEK.
&&
.AVIATION...
220400Z...COAST/VALLEYS...STRATUS ALONG THE COAST WITH BASES 1000 FT
AND TOPS TO 1500 FT MSL SPREADING 15-20 SM INLAND THROUGH 15Z WED.
STRATUS CLEARING TOWARD THE COAST BTWN 17-19Z WED.
MTNS/DESERTS...SCT-BKN CLOUDS OVER THE MOUNTAINS AND DESERTS TONIGHT
WITH BASES FROM 15-20KFT. ON WEDNESDAY...SCT-BKN CUMULUS BUILDING
OVER THE MTNS GROWING INTO SCATTERED TSTMS BTWN 18Z-01Z WITH CLOUD
TOPS 40-50KFT.
&&
.FIRE WEATHER...ISOLATED TO SCATTERED LIGHTNING ACROSS LOWER
ELEVATIONS...DESERT SLOPES AND VALLEYS DUE TO THE ELEVATED NATURE OF
THUNDERSTORMS TONIGHT AND WEDNESDAY MORNING BRINGS SOME CONCERN.
UNCERTAINTY REMAINS WITH THE COVERAGE AND AMOUNT OF LIGHTNING. MOST
FAVORABLE AREAS ARE THE HIGH DESERTS AND ALONG AND TO THE EAST OF
I-15. AT THIS TIME HAVE LEFT THE FIRE WEATHER FORECAST PER
COORDINATION OF THE DAY SHIFT.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...TARDY
AVIATION/MARINE...MOEDE
AREA FORECAST DISCUSSION
NWS DENVER CO
744 PM MDT THU AUG 23 2012
.UPDATE...UPPER LEVEL LOW OVER THE FOUR CORNERS WILL SLOWLY DRIFT
EAST TONIGHT. SHOWER AND THUNDERSTORM ACTIVITY IS ALREADY
DECREASING THIS EVENING AS THE AIRMASS STABILIZES. SKIES HAVE
CLEARED OVER NORTHEAST COLORADO WHERE DRIER AIR HAS MOVED IN.
DECREASED POPS EVERYWHERE EXCEPT SOUTH AND WEST OF DENVER WHERE
SCATTERED SHOWERS CONTINUE. WILL LEAVE POPS IN THE FORECAST
THROUGH NIGHT WITH THE HIGHEST POPS TO THE SOUTH AND WEST OF
DENVER CLOSER TO THE LOW. THE LOWEST POPS WILL BE OVER THE
NORTHEAST. DECREASED LOW TEMPERATURES FOR THE NORTHEAST PLAINS
WHERE CLEARING SKIES WILL ALLOW FOR BETTER COOLING.
&&
.AVIATION...MID AND HIGH CLOUDS ARE EXPECTED TO CONTINUE TO STREAM
OVER THE AREA TONIGHT. THERE WILL BE A SLIGHT CHANCE FOR A SHOWER
THROUGH 12Z. SOUTHWEST WINDS WILL DECREASE AND BE SOUTHERLY MOST
OF THE NIGHT.
&&
.PREV DISCUSSION... /ISSUED 340 PM MDT THU AUG 23 2012/
SHORT TERM...A RATHER DISORGANIZED UPPER LEVEL TROUGH OVER
SOUTHERN UT AND NORTHERN AZ THIS AFTERNOON WILL SLOWLY MOVE EAST
ACROSS SOUTHERN COLORADO TONIGHT AND FRIDAY. THE AIRMASS WILL
REMAIN VERY MOIST BUT SO FAR THE SHOWERS AND TSTMS HAVE BEEN SLOW
TO DEVELOP THIS AFTERNOON. THE LATEST HRRR HOWEVER CONTINUES TO
DEVELOP PRECIPITATION OVER THE CWFA TONIGHT...WITH THE BEST
POTENTIAL TO THE WEST AND SOUTH OF DENVER. PRECIPITABLE WATER
VALUES WILL BE OVER ONE INCH WITH SLOW STORM MOTIONS SO A FEW
STORMS COULD PRODUCE BRIEF HEAVY RAINFALL...BUT EXTENSIVE CLOUD
COVER TODAY HAS LIMITED THEIR DEVELOPMENT SO FAR. WL KEEP THE POPS I
INHERITED FOR THE MOST PART...ONLY CHANGE WAS TO INCREASE THE POPS
TO CHC NEAR THE SRN FRONT RANGE FOOTHILLS AND PALMER DIVIDE. IN A
NUTSHELL...ALTHOUGH THE POTENTIAL FOR HEAVY RAIN EXISTS FOR THE
BURN AREAS...THE THREAT STILL TO BE MODERATE UNTIL MAYBE O2Z THEN LOW.
ON FRIDAY...VERY SIMILAR TO TODAY WITH A BIT MORE WARMING.
FORECAST SOUNDINGS FRIDAY AFTERNOON RANGE 200-300 J/KG AT KDEN TO
700-1100 J/KG AND KLIC AND KAKO RESPECTIVELY. THERE WILL BE SOME
WEAK QG ASCENT ASSOCIATED WITH THE TROUGH WHICH MAY HELP ENHANCE
THE PCPN BUT EXTENSIVE CLOUD COVER MAY AGAIN LIMIT THE STRENGTH/COVERAGE
OF THE TSTMS. BEST POPS WILL BE OVER THE SRN HALF OF THE CWFA
WITH DRYING DEVELOPING OVER THE NRN HALF OF THE CWFA ONCE THE
SYSTEM MAKES ITS WAY INTO SERN CO LATE IN THE DAY.
LONG TERM...TROUGH TO BE CENTERED ACROSS EASTERN COLORADO FRIDAY
EVENING. SHOULD CONTINUE TO SEE DRIER AND MORE SUBSIDENT AIR
MOVING IN FROM THE NORTH. STILL SOME CHANCE FOR THUNDERSTORMS...MAINLY
ACROSS THE SOUTHERN SECTIONS OF THE CFWA IN THE AREA OF BEST MID
LEVEL QG ASCENT. PRECIPITABLE WATER VALUES ON THE DECREASE...BUT
STILL CLOSE TO AN INCH ALONG PALMER DIVIDE. MAY STILL SEE BRIEF
MODERATE TO HEAVY RAIN WITH THE STORMS THERE...WITH LIGHTER
AMOUNTS ELSEWHERE. COULD ALSO SEE SOME GUSTY OUTFLOW WINDS. TROUGH
TO SLOWLY MOVE INTO WESTERN KANSAS OVERNIGHT WITH MOST IF NOT ALL
OF THE ASCENT EAST OF THE AREA. FOR THIS REASON...WILL DROP MOST
OF THE POPS AND WEATHER AFTER MIDNIGHT KEEPING A SLIGHT CHANCE
OVER THE HIGHER MOUNTAINS. ON SATURDAY...TROUGH TO BE CENTERED
OVER CENTRAL AND WESTERN KANSAS AS UPPER RIDGE BUILDS ACROSS GREAT
BASIN. MODELS CONTINUE TO SHOW COLD FRONT MOVING THROUGH THE
PLAINS DURING THE EARLY MORNING HOURS. WINDS COULD GUST TO AROUND
20 KTS FOR A COUPLE HOURS FOLLOWING FRONT. COOLER AIR EXPECTED
FOLLOWING FRONT WITH HIGHS ONLY IN THE LOWER 80S ACROSS PLAINS.
THE COOLER AIR WILL ALSO HELP TO STABILIZE THE ATMOSPHERE.
MOUNTAINS NOT EXPECTED TO BE AFFECTED BY THE FRONT SOME
TEMPERATURES THERE TO BE SIMILAR TO FRIDAY`S READINGS. AIRMASS TO
BE SLIGHTLY UNSTABLE OVER THE HIGH COUNTRY BY THE AFTERNOON AND
WITH LINGERING MOISTURE...COULD SEE SOME HIGH BASED STORMS DEVELOP
ACROSS THE HIGHER TERRAIN DURING THE AFTERNOON CONTINUING INTO THE
EVENING. FOR SUNDAY...HIGH PRESSURE TO CONTINUE TO BUILD ACROSS
GREAT BASIN AS WELL AS WESTERN COLORADO. AS A RESULT...AIRMASS TO BE
MAINLY DRY AND WARMER WITH HIGHS INTO THE MID AND UPPER 80S ACROSS
PLAINS. STILL SOME MOISTURE NOTED ON CROSS SECTIONS ACROSS
MOUNTAINS FOR A SLIGHT CHANCE OF AFTERNOON AND EVENING HIGH BASED
STORMS. BOTH NAM AND GFS HINT AT A WEAK DISTURBANCE MOVING ACROSS
CENTRAL PLAINS DURING THE AFTERNOON. THERE IS SOME WEAK QG ASCENT
AS WELL. BOTH MODELS ALSO PAINT SOME LIGHT QPF ACROSS AREA
INCLUDING PLAINS. BUT AIRMASS ALSO FAIRLY DRY AS NOTED BY LOWER
PRECIPITABLE WATER VALUES. FOR NOW WILL NOT INTRODUCE POPS FOR
PLAINS BUT WILL ADD A BIT MORE CLOUD.
FOR THE MONDAY THROUGH THURSDAY PERIOD...MODELS SHOW UPPER RIDGE
ACROSS COLORADO THROUGH THE PERIOD...THOUGH ECMWF SHOW RIDGE OVER
CENTRAL PLAINS BY LATE WEDNESDAY WITH UPPER TROUGH ACROSS GREAT
BASIN. ECMWF LOOKS TO THE THE OUTLIER AT THIS POINT AND WILL
DISCOUNT. SO SHOULD SEE A MAINLY DRY AND WARM AIRMASS OVER THE
AREA THROUGH THE PERIOD. SOME MOISTURE WILL BE PRESENT FOR A
SLIGHT CHANCE OF THUNDERSTORMS OVER THE HIGH COUNTRY EACH
AFTERNOON AND EVENING. GUIDANCE INDICATING HIGHS COULD BE 90
DEGREES OR BETTER DURING THIS PERIOD...WHICH WILL LIKELY BREAK THE
STRING OF DAYS OF 90 DEGREES OR GREATER FOR DENVER...THE RECORD
BEING 61 DAYS. CURRENTLY DENVER ONLY 2 DAYS FROM TYING THE
RECORD...AND STRING COULD BE BROKEN WEDNESDAY IF GUIDANCE IS
CORRECT.
AVIATION...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SHOWERS
AND TSTMS DEVELOPING WEST AND SOUTH OF DENVER SHOULD DRIFT INTO
THE DENVER AREA THROUGH O0-02Z. IF TSTMS DEVELOP AT KDEN THEN CIGS
COULD DEVELOP IN THE 5-6 KFT AGL RANGE. WITH SFC LOW TO THE SOUTH
WINDS MAY CONTINUE TO FLUCTUATE FM NWLY TO NELY THROUGH THIS
EVENING. DEVELOPING SHOWERS AND TSTMS WILL ONLY CONFUSE THE ISSUE
FURTHER. SHOULD SEE WINDS TRANSITION TO SWLY LATE THIS EVENING
BUT DRAINAGE WINDS WILL BE SLOW TO DEVELOP WITH SHOWERS AND CLOUD
COVER LINGERING OVERNIGHT.
HYDROLOGY...THREAT OF THUNDERSTORMS WILL BE GREATEST PRIOR TO 02Z
WITH LINGERING LIGHT RAIN SHOWERS OVERNIGHT. A THUNDERSTORM THIS
AFTN OR EARLY THIS EVENING COULD PRODUCE A MODERATE TO HEAVY RAIN
SHOWER WITH A QUARTER OF ONE HALF INCH OF RAIN IN 30 MINUTES. IN
SPITE OF THE HIGH MOISTURE CONTENT EXTENSIVE CLOUD COVER HAS
LIMITED THE TSTMS DEVELOPMENT SO FAR THIS AFTN. THE THREAT OF HEAVY
RAIN WILL BE MODERATE IN THE BURN AREAS UNTIL 02Z THEN LOW
THEREAFTER.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....D-L
UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS MIAMI FL
230 AM EDT WED AUG 22 2012
.AVIATION...
A LARGE SHIELD OF LIGHT TO MODERATE RAIN CONTINUES TO IMPACT THE
AREA FROM APF TO THE LAKE REGION EARLY THIS MORNING. EXPECT THIS
GENERAL TREND TO PERSIST THROUGH THE EARLY MORNING PERIOD...THEN
SHIFT INLAND AND ACROSS THE LAKE AND PALM BEACH REGION LATER
TODAY. IN ADDITION...PERIODS WITH HEAVIER SHRA/TSTMS EMBEDDED
WITHIN THIS ACTIVITY MOVING ASHORE ALONG THE GULF COAST WILL
REMAIN POSSIBLE THROUGH THIS TIME. THIS WILL RESULT IN PERIODS
WITH SUB VFR CIGS/VSBYS. OTHERWISE...THE LATEST NUMERICAL GUIDANCE
CONTINUES TO INDICATE DRIER AIR BEGINNING TO SPREAD NORTH ACROSS
SOUTH FLORIDA THROUGH THE COURSE OF THE DAY TODAY WITH THE WINDS
EXPECTED TO GRADUALLY BACK TOWARD THE EAST THROUGH THE PERIOD. 85/AG
&&
.PREV DISCUSSION... /ISSUED 1040 PM EDT TUE AUG 21 2012/
UPDATE...INCREASED POPS AREA WIDE FOR TONIGHT...ADDING ISOLATED
TSTORMS POTENTIAL TO THE EAST COAST AND SCATTERED ACTIVITY FOR THE
INTERIOR AND GULF COAST BASED ON LATEST RADAR TRENDS OF ACTIVITY
MOVING IN FROM THE GULF AND CONVECTION AGAIN MOVING OFF OF CUBA
WHICH COULD IMPACT EASTERN AREAS OVERNIGHT. /GREGORIA
PREV DISCUSSION... /ISSUED 806 PM EDT TUE AUG 21 2012/
AVIATION...
LINGERING SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS THE
REGION THIS EVENING. THE EAST COAST TERMINALS DO NOT HAVE ANY
THUNDERSTORMS IN THE VICINITY ALTHOUGH TERMINAL KPBI CURRENTLY HAS
LIGHT SHOWERS. MAINLY VFR CONDITIONS EXPECTED FOR THE EAST COAST
TERMINALS THIS EVENING ALTHOUGH KPBI COULD BRIEFLY HAVE SUB-VFR
CONDITIONS WITH ANY MODERATE SHOWERS OVER THE NEXT HOUR OR SO.
TERMINAL KAPF WAS ASSIGNED VCTS BUT SO FAR THUNDERSTORMS ARE NEAR
FT. MYERS AND ADJACENT GULF WATERS. IT IS POSSIBLE HOWEVER SOME
THUNDERSTORMS COULD MOVE ACROSS THE GULF WATERS AND AFFECT KAPF THIS
EVENING WITH SUB-VFR CONDITIONS IF THEY OCCUR AND WILL AMEND IF
NECESSARY.
60
PREV DISCUSSION... /ISSUED 209 PM EDT TUE AUG 21 2012/
DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE INTERIOR AND PUSH TOWARDS THE NORTHEAST SECTIONS OF THE CWA THIS
AFTERNOON AND INTO THE EVENING UNDER THE SOUTHWEST FLOW ALOFT. A
FEW STORMS COULD BE STRONG...WITH THE MAIN THREAT BEING STRONG
WINDS OF 40 TO 50 MPH. THE HRRR IS SHOWING THAT A LINE OF STORMS
MAY MOVE ACROSS THE EASTERN GULF AND INTO CENTRAL FLORIDA...WITH
THE TAIL END OF THIS LINE OF SHOWERS AND THUNDERSTORMS POSSIBLY
MOVING INTO THE LOCAL GULF WATERS AND PORTIONS OF THE NORTHWEST
AFTER 00Z. THIS IS CONSISTENT WITH THE 12Z GFS SHOWING A PIECE OF
ENERGY ROTATING AROUND THE BASE OF THE TROUGH AND ACROSS CENTRAL
FLORIDA OVERNIGHT. SO WILL KEEP 20-30 POPS FOR THIS REGION.
THE UPPER TROUGH ALONG THE EASTERN SEABOARD WILL BEGIN TO FILL AND
LIFT TO THE NORTHEAST TONIGHT AND WEDNESDAY...BUT A WEAKNESS WILL
REMAIN OVER THE GULF AND THE WESTERN ATLANTIC THROUGH THE WEEKEND.
AT THE SURFACE...THE QUASI-STATIONARY FRONT OVER NORTH FLORIDA
WILL SLOWLY DRIFT SOUTHWARD TONIGHT INTO WEDNESDAY AND THEN BEGIN
TO WASH OUT AND DRIFT NORTHWARD INTO THURSDAY. THE SUBTROPICAL
RIDGE OVER THE WESTERN ATLANTIC WILL MOVE NORTHWARD AND THE DRY
AIR AND HAZE OVER THE BAHAMAS IS EXPECTED TO PUSH INTO SOUTH
FLORIDA ON WEDNESDAY AND THURSDAY. IN ADDITION...THE LOW/MID LEVEL
FLOW WILL SHIFT FROM THE SOUTHWEST TO THE EAST AND SOUTHEAST BY
THURSDAY.
WITH PWATS FALLING TO AROUND 1.5 INCHES ON WEDNESDAY ALONG THE
SOUTHEAST COAST...ONLY MINIMAL RAIN CHANCES ARE EXPECTED.
STEERING FLOW WILL PUSH STORMS SLOWLY TO THE NORTH ON WEDNESDAY.
HIGHER MOISTURE WILL ALSO LINGER AROUND THE LAKE ON WEDNESDAY...SO
THERE WILL STILL BE A CHANCE OF STORMS FOR THE LAKE OKEECHOBEE
REGION. MODEL SOUNDINGS ARE SHOWING RELATIVELY STEEP LAPSE RATES
ABOVE THE INVERSION AND STRONG STORMS AND POSSIBLY AN ISOLATED
SEVERE STORM CANNOT BE RULED OUT ON WEDNESDAY. HEAT INDICES WILL
BE THE TYPICAL 100-108F FOR THIS TIME OF YEAR...WITH THE HIGHEST
READINGS ACROSS THE INTERIOR.
EVEN DRIER AIR IS EXPECTED TO MOVE INTO THE REGION ON
THURSDAY...WITH PWATS ACROSS THE REGION DROPPING TO 1.3-1.6 INCHES.
WITH THE FLOW SHIFTING TO THE EAST AND SOUTHEAST...EXPECT THE EAST
COAST TO MAINLY STAY DRY...WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE INTERIOR AND TOWARDS THE GULF COAST.
FOR FRIDAY INTO SATURDAY...THE PRESSURE GRADIENT MAY BEGIN TO
TIGHTEN AS TROPICAL DEPRESSION NINE MOVES NEAR HAITI AND EASTERN
CUBA. SO SOMEWHAT BREEZIER EASTERLY FLOW COULD BEGIN ON FRIDAY AND
SATURDAY WITH AN INCREASE IN LOW LEVEL MOISTURE AND RAIN CHANCES.
IT IS STILL TOO EARLY TO DETERMINE THE IMPACTS OF TROPICAL
DEPRESSION NINE ON SOUTH FLORIDA OR THE SURROUNDING MARINE AREAS IN
THE LONG TERM. HOWEVER...THERE IS INCREASING POTENTIAL THAT SOUTH
FLORIDA AND/OR THE SURROUNDING MARINE AREAS COULD BE IMPACTED LATE
THIS WEEKEND INTO EARLY NEXT WEEK. SO NOW IS A GOOD TIME TO
REVIEW INDIVIDUAL TROPICAL CYCLONE PREPAREDNESS PLANS. FOR THE
LATEST INFORMATION REGARDING TROPICAL DEPRESSION NINE...CONTINUE
TO MONITOR THE LATEST FORECASTS FROM THE NATIONAL HURRICANE
CENTER.
AVIATION...
A FEW THUNDERSTORMS COULD DEVELOP THIS AFTERNOON
MAINLY TOWARD KPBI AND KFXE, BUT EXPECT TO HAVE ACTIVITY CLOSE
ENOUGH TO THE REST OF THE ERN TERMINALS TO BE WORTH MENTIONING
VCTS IN TAFS. WL EXPECT ANY SHWR/TSTM TO REMAIN WELL AWAY FROM
KAPF AND NO AFFECT OPERATIONS. EVENING ACTIVITY SHOULD TAPER OFF
BY 00Z TONIGHT. SFC SHOULD REMAIN MOSTLY SE, ALTHOUGH BECOMING
LIGHT AND VARIABLE AFTER 00Z AND INCREASING AGAIN TO AROUND 8-10
KTS AFTER 13Z WEDNESDAY.
MARINE...
A RIDGE OF HIGH PRESSURE WILL BE LOCATED OVER THE SOUTH FLORIDA
WATERS THROUGH THE MIDDLE OF THE WEEK BEFORE SHIFTING NORTH DURING
THE LATTER PART OF THE WEEK. THIS WILL LEAD TO WINDS OUT OF THE
SOUTH BECOMING EASTERLY LATE IN THE WEEK. THE PRESSURE GRADIENT IS
EXPECTED TO INCREASE FRIDAY AND SATURDAY AS TROPICAL DEPRESSION
NINE MOVES NEAR HAITI AND EASTERN CUBA. THE FORECAST FOR LATE THIS
WEEKEND BECOMES HIGHLY DEPENDENT ON THE EVOLUTION THIS TROPICAL
CYCLONE. THE FORECAST TRACK OF THIS POTENTIAL SYSTEM IS IN THE
GENERAL DIRECTION OF THE REGIONAL WATERS AND SHOULD BE CLOSELY
MONITORED BY ALL MARINE INTERESTS OVER THE COMING DAYS.
FIRE WEATHER...
SOUTH TO SOUTHWEST WINDS WILL BE OVER SOUTH FLORIDA AGAIN ON
WEDNESDAY AS A HIGH PRESSURE RIDGE PERSISTS JUST SOUTH OF THE
AREA OVER THE KEYS AND FLORIDA STRAITS. ISOLATED TO SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON ON
WEDNESDAY BUT AFFECTING MAINLY THE INTERIOR AND THE LAKE
OKEECHOBEE REGION AS THE ACTIVITY WILL MOVE TO THE NORTHEAST. EAST
AND WEST COAST SEA BREEZES ARE EXPECTED TO DEVELOP LATE THIS
MORNING AND CONTINUE INTO THIS AFTERNOON ON WEDNESDAY. FLOW WILL
BECOME MORE EASTERLY ON THURSDAY AND STRENGTHEN FRIDAY INTO THE
WEEKEND AS THE PRESSURE GRADIENT INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 78 89 79 / 20 10 10 20
FORT LAUDERDALE 91 80 91 79 / 10 10 10 20
MIAMI 92 79 91 78 / 10 10 10 20
NAPLES 93 77 93 76 / 40 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...15/JR
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1047 PM CDT THU AUG 23 2012
.DISCUSSION...
947 PM CDT
UPDATE...
1043 PM
FOR REST OF TONIGHT...
NO SIGNIFICANT CHANGES MADE TO FORECAST GRIDS AND DERIVED TEXT
PRODUCTS THOUGH DID DO SOME TWEAKING FOR RECENT TRENDS.
DURING THE LATER AFTERNOON TMKE RADAR DETECTED AN INCREASINGLY
DEFINED LINE OF LOW LEVEL CONVERGENCE FROM JUST OFFSHORE OF
HIGHWOOD AND LAKE BLUFF IN SOUTHEAST LAKE CO. IL BOWING OUT OVER
THE LAKE THEN CURVING BACK TO THE SHORELINE NEAR PORT WASHINGTON
IN EAST CENTRAL OZAUKEE CO. WI.
WHILE THE RUC13 HAS SHOWN SURFACE CONVERGENCE ALONG AND JUST
INLAND IN THIS AREA DUE TO A MODEST LAKE BREEZE...THE HRR3
PLACED THIS LINEAR CONVERGENT ZONE...DUE TO SPEED CONVERGENCE PER
THIS MODEL...MUCH BETTER.
SURFACE/LOW LEVEL CONVERGENCE COMBINED WITH WEAK LOW LEVEL WARM
AIR ADVECTION AND VERY MODEST MID LEVEL COOLING AND A VERY MINOR
DISTURBANCE MOVING EAST ACROSS SOUTHERN WI AND NORTHERN IL DURING
THE LATE AFTERNOON THROUGH MID EVENING COMBINED TO ALLOW CAPE
VALES TO GROW AND SHOWERS TO FORM ALONG THIS LINE. WHILE THE
SOUTHERN EXTENT OF THESE SHOWERS HAS BEEN MOVING NORTHWARD AND
WEAKENING DURING THE MID TO LATE EVENING... AT THE SAME TIME
ANOTHER SIMILAR LINE HAS APPEARED BETWEEN THE SAME END POINTS BUT
BOWING ALL THE WAY OUT TO MID LAKE OFF OF RAC AND MKE. A FEW WEAK
SHOWERS WERE ALONG THIS LINE.
PREMISED ON THE HRR CONTINUING TO DEPICT THE LINEAR CONVERGENCE
ZONE...THE AREA OF CONVERGENCE WILL SHIFT SOUTH TO OFF OF THE IL
SHORE BEFORE WEAKENING AS IT DRIFTS OUT TOWARD MID LAKE BY 06Z.
THUS THE THREAT OF SHOWERS WITH THESE FEATURES LOOKS TO BE LOW AT
BEST.
A LONE SHOWER MOVED INTO SOUTHERN LASALLE CO. EARLY THIS EVENING
THEN DISSIPATED AS IT CONTINUE TO THE NORTHEAST. THIS ISOLATED
SHOWER WAS A RESULT OF THE INCREASED LIFT ASSOCIATED WITH THE
MINOR SHORT WAVE MOVING OVER THE NORTHERN END OF AN AREA OF WELL
DEFINED MODERATE CU WITH THE LOSS OF HEATING RESULTING IN ITS
DEMISE.
FOR THE OVERNIGHT...LATEST RUNS OF NAM...RUC AND HRR ALL KEEP THE
LOCAL FORECAST AREA DRY WITH THE RAIN FALLING FROM EASTERN WI
SOUTHWESTWARD ACROSS IA. WITH A STRONGER SHORT WAVE TROUGH MOVING
EAST ACROSS MN AND FAR NORTHERN IA AT LATE EVENING AND PROGGED TO
CONTINUE EAST HAVE RETAINED THE SLIGHT CHANCE POPS ACROSS THE
NORTHERN PORTION OF THE FORECAST AREA...AND WITH THE TROUGH TO
REACH FAR EASTERN WI AND FAR NORTHEAST IL BY EARLY TO MID MORNING
HAVE LEFT THE LOW POPS DURING FRI AS IS.
TRS
//PREV DISCUSSION...
344 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES THIS FORECAST PERIOD ARE WITH
CLOUD TRENDS THIS EVENING AND TONIGHT AS WELL AS FOR A SLIGHT
CHANCE OF LIGHT SHOWERS TONIGHT.
RELATIVELY QUIET BUT WARM CONDITIONS CURRENTLY ACROSS THE
CWA...WITH SOME MID/HIGH LEVEL CLOUD COVER PASSING OVERHEAD. AS
SEVERAL MID LEVEL FEATURES CONTINUE TO SHIFT EAST THIS
EVENING...SOUTHWEST MID LEVEL FLOW WILL ALLOW FOR A CONTINUED
SETUP FOR WAA TO OCCUR. ALTHOUGH THIS WAA/ASCENT WILL BE FAIRLY
WEAK...IT SHOULD BE ENOUGH TO OVERCOME SOME DRIER AIR AND ALLOW
FOR REDEVELOPMENT OF MID LEVEL CLOUDS ACROSS MUCH OF THE REGION.
ALTHOUGH NOT EXACTLY THE SAME SETUP FROM THIS MORNING...A SIMILAR
SITUATION WITH PARTLY CLOUDY/CLOUD SKIES AND SOME LIGHT SHOWERS
COULD ONCE AGAIN OCCUR...ESPECIALLY WITH SOME WEAK MID LEVEL
RIPPLES PASSING OVERHEAD AS WELL AS A LIFTING FRONTAL BOUNDARY. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT SHOWERS TONIGHT.
THUNDER SHOULD BE NONEXISTENT ONCE AGAIN AS BETTER FORCING WILL BE
TIED MORE TOWARD A STRONGER WAVE FURTHER TO THE NORTH ACROSS
WISCONSIN TONIGHT. AS THIS WAVE SHIFTS EAST OF THE REGION FRIDAY
MORNING...ANY PRECIP/CLOUD COVER WILL EXIT AND DIMINISH MAKING WAY
FOR PARTLY CLOUDY SKIES. WITH THERMAL AXIS SHIFTING
OVERHEAD...TEMPS SHOULD RISE FAIRLY EASILY TOMORROW WITH HIGH
TEMPERATURES IN THE LOWER 90S EXPECTED. WITH SOME LOCATIONS IN THE
WESTERN CWA ALREADY OBSERVING LOWER 90S TODAY...IT WOULD NOT BE
OUT OF THE QUESTION FOR SOME MID 90S TO OCCUR AS WELL. DESPITE
THIS WARM UP...LOW HUMIDITY AND SOME SUNSHINE WILL HELP TO PROVIDE
ANOTHER PLEASANT DAY. HAVE ALSO MAINTAINED LOWER 90S INTO SATURDAY
WITH REALLY NO CHANGE IN THE OVERALL SETUP EXPECTED.
THE NEXT BEST CHANCE FOR PRECIP IS STILL APPEARING TO BE LATE IN
THE WEEKEND AS A WAVE EJECTS OUT OF THE CENTRAL PLAINS. THIS
SHOULD INDUCE SOME DECENT PRESSURE FALLS AND HELP THIS SYSTEM WRAP
SOME GOOD MOISTURE INTO IT. WITH GUIDANCE STILL VARYING ON ITS
OVERALL EVOLUTION...HAVE NOT GONE TOO HIGH WITH POPS FOR SUNDAY
BUT DID INCREASE TO HIGH CHANCE POPS FOR MOST OF THE CWA ON SUNDAY
WITH MOST GUIDANCE SPEEDING UP THIS SYSTEM. THIS SYSTEM WILL NEED
TO CONTINUE BE MONITORED...DUE TO THE OVERALL STRENGTH OF THE
CONVECTIVE POTENTIAL STILL UNKNOWN AS WELL AS CHANCES FOR SOME
DECENT RAINFALL.
RODRIGUEZ
&&
.AVIATION...
////ORD AND MDW CONCERNS...UPDATED 03Z...
* NONE.
KJB
//DISCUSSION...UPDATED 00Z...
OVERALL IT APPEARS TO BE A QUIET PERIOD WEATHER WISE FOR THE
TERMINALS THROUGH FRIDAY. HOWEVER...THERE IS A VERY SLIGHT CHANCE
THAT SOME ISOLATED TO WIDELY SCT -SHRA COULD DEVELOP ACROSS NORTHERN
ILLINOIS THIS EVENING AND INTO THE OVERNIGHT HOURS. THE ATMOSPHERE
ACROSS THE REGION IS WEAKLY UNSTABLE AHEAD OF AN APPROACHING WARM
FRONT ACROSS NORTH CENTRAL SECTIONS OF THE STATE. IT ALSO APPEARS
THAT A WEAK MID LEVEL DISTURBANCE ACROSS EASTERN IOWA IS PRODUCING
SOME WEAK ASCENT ACROSS PORTIONS OF NORTHERN ILLINOIS LATE THIS
AFTERNOON. THIS HAS HELPED SPARK OFF A FEW ISOLATED SHOWERS ACROSS
PUTNAM AND MARSHALL COUNTIES IN CENTRAL ILLINOIS OVER THE PAST HOUR
WITHIN THE VICINITY OF THE SURFACE FRONT. HOWEVER...DUE TO THE LOW
COVERAGE OF ANY ACTIVITY THAT AFFECTS NORTHERN ILLINOIS TONIGHT...I
HAVE OPTED TO CONTINUE A DRY FORECAST AT THE TERMINALS. ANY CLOUD
COVER THROUGH THE PERIOD WILL BE AT OR ABOVE 10,000 FEET AGL.
SOUTHERLY WINDS WILL CONTINUE THROUGH THE PERIOD AS A LARGE AREA OF
HIGH PRESSURE REMAINS ACROSS THE EASTERN CONUS...WHILE LOW PRESSURE
RESIDES ACROSS THE NORTHERN PLAINS. IT APPEARS THAT THE WINDS WILL
INCREASE DURING THE MORNING ON FRIDAY AS ATMOSPHERIC MIXING MIXES
DOWN SOME HIGHER MOMENTUM FROM ALOFT. THIS LOOKS TO RESULT IN
DAYTIME GUSTS IN THE 15 TO 20 KT RANGE.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR. WX NIL.
SUNDAY...CHANCE TSRA. OTHERWISE...VFR.
MONDAY...CHANCE TSRA EARLY. OTHERWISE...VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
229 PM CDT
A TROUGH OF LOW PRESSURE STRETCHING FROM SASKATCHEWAN TO THE
SOUTHERN HIGH PLAINS WILL REMAIN NEARLY STATIONARY THROUGH FRIDAY
NIGHT...WHILE A DEEP AREA OF LOW PRESSURE DEVELOPS WITHIN THE
NORTHERN PERIPHERY OF THIS TROUGH OVER SASKATCHEWAN. THIS LOW WILL
MOVE NORTHEAST ACROSS MANITOBA SATURDAY AND SATURDAY NIGHT...AND
OVER HUDSON BAY SUNDAY AND SUNDAY NIGHT. THIS WILL SET UP A
PROLONGED PERIOD OF SOUTH WINDS ACROSS LAKE MICHIGAN THROUGH THE
WEEKEND. WARM AIR SPREADING ACROSS THE LAKE ON THESE SOUTH WINDS
WILL TEND TO LIMIT THE DEPTH OF THE MIXED LAYER OVER THE WATER...
WITH MODEL FORECAST SOUNDINGS DEPICTING 15-20 KTS AND SOME GUSTS
INTO THE 20-25 KT RANGE PARTICULARLY OVER THE NORTHERN AND NORTH
CENTRAL PARTS OF THE LAKE. SOME GUIDANCE DEPICTS A WEAKER SURFACE
WAVE DEVELOPING ACROSS THE MIDWEST BY EARLY SUNDAY...ALONG THE COLD
FRONT TRAILING THE DEEPER CANADIAN LOW. SOUTH-SOUTHEAST WINDS MAY
BRIEFLY PICK UP NEAR 20 KTS ON THE SOUTHERN PORTION OF THE LAKE
AHEAD OF THIS WAVE EARLY SUNDAY. THE COLD FRONT WILL THEN TRANSLATE
EAST ACROSS LAKE MICHIGAN SUNDAY NIGHT...WITH THE GRADIENT WEAKENING
IN THE VICINITY OF THE FRONTAL TROUGH WITH WINDS SHIFTING TO THE
NORTH-NORTHWEST. WEAK HIGH PRESSURE WILL THEN SPREAD ACROSS THE
UPPER MIDWEST BEHIND THE FRONT SUNDAY NIGHT AND MONDAY...MOVING
ACROSS THE WESTERN AND NORTHERN LAKES MONDAY NIGHT AND TUESDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1044 PM CDT THU AUG 23 2012
.DISCUSSION...
947 PM CDT
UPDATE...
1042 PM
FOR REST OF TONIGHT...
NO SIGNIFICANT CHANGES MADE TO FORECAST GRIDS AND DERIVED TEXT
PRODUCTS THOUGH DID DO SOME TWEAKING FOR RECENT TRENDS.
DURING THE LATER AFTERNOON TMKE RADAR DETECTED AN INCREASINGLY
DEFINED LINE OF LOW LEVEL CONVERGENCE FROM JUST OFFSHORE OF
HIGHWOOD AND LAKE BLUFF IN SOUTHEAST LAKE CO. IL BOWING OUT OVER
THE LAKE THE CURVING BACK TO THE SHORELINE NEAR PORT WASHINGTON
IN EAST CENTRAL OZAUKEE CO. WI.
WHILE THE RUC13 HAS SHOWN SURFACE CONVERGENCE ALONG AND JUST
INLAND IN THIS AREA DUE TO A MODEST LAKE BREEZE...THE HRR3
PLACED THIS LINEAR CONVERGENT ZONE...DUE TO SPEED CONVERGENCE PER
THIS MODEL...MUCH BETTER.
SURFACE/LOW LEVEL CONVERGENCE COMBINED WITH WEAK LOW LEVEL WARM
AIR ADVECTION AND VERY MODEST MID LEVEL COOLING AND A VERY MINOR
DISTURBANCE MOVING EAST ACROSS SOUTHERN WI AND NORTHERN IL DURING
THE LATE AFTERNOON THROUGH MID EVENING COMBINED TO ALLOW CAPE
VALES TO GROW AND SHOWERS TO FORM ALONG THIS LINE. WHILE THE
SOUTHERN EXTENT OF THESE SHOWERS HAS BEEN MOVING NORTHWARD AND
WEAKENING DURING THE MID TO LATE EVENING... AT THE SAME TIME
ANOTHER SIMILAR LINE HAS APPEARED BETWEEN THE SAME END POINTS BUT
BOWING ALL THE WAY OUT TO MID LAKE OFF OF RAC AND MKE. A FEW WEAK
SHOWERS WERE ALONG THIS LINE.
PREMISED ON THE HRR CONTINUING TO DEPICT THE LINEAR CONVERGENCE
ZONE...THE AREA OF CONVERGENCE WILL SHIFT SOUTH TO OFF OF THE IL
SHORE BEFORE WEAKENING AS IT DRIFTS OUT TOWARD MID LAKE BY 06Z.
THUS THE THREAT OF SHOWERS WITH THESE FEATURES LOOKS TO BE LOW AT
BEST.
A LONE SHOWER MOVED INTO SOUTHERN LASALLE CO. EARLY THIS EVENING
THEN DISSIPATED AS IT CONTINUE TO THE NORTHEAST. THIS ISOLATED
SHOWER WAS A RESULT OF THE INCREASED LIFT ASSOCIATED WITH THE
MINOR SHORT WAVE MOVING OVER THE NORTHERN END OF AN AREA OF WELL
DEFINED MODERATE CU WITH THE LOSS OF HEATING RESULTING IN ITS
DEMISE.
FOR THE OVERNIGHT...LATEST RUNS OF NAM...RUC AND HRR ALL KEEP THE
LOCAL FORECAST AREA DRY WITH THE RAIN FALLING FROM EASTERN WI
SOUTHWESTWARD ACROSS IA. WITH A STRONGER SHORT WAVE TROUGH MOVING
EAST ACROSS MN AND FAR NORTHERN IA AT LATE EVENING AND PROGGED TO
CONTINUE EAST HAVE RETAINED THE SLIGHT CHANCE POPS ACROSS THE
NORTHERN PORTION OF THE FORECAST AREA...AND WITH THE TROUGH TO
REACH FAR EASTERN WI AND FAR NORTHEAST IL BY EARLY TO MID MORNING
HAVE LEFT THE LOW POPS DURING FRI AS IS.
TRS
&&
.PREV DISCUSSION...
344 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES THIS FORECAST PERIOD ARE WITH
CLOUD TRENDS THIS EVENING AND TONIGHT AS WELL AS FOR A SLIGHT
CHANCE OF LIGHT SHOWERS TONIGHT.
RELATIVELY QUIET BUT WARM CONDITIONS CURRENTLY ACROSS THE
CWA...WITH SOME MID/HIGH LEVEL CLOUD COVER PASSING OVERHEAD. AS
SEVERAL MID LEVEL FEATURES CONTINUE TO SHIFT EAST THIS
EVENING...SOUTHWEST MID LEVEL FLOW WILL ALLOW FOR A CONTINUED
SETUP FOR WAA TO OCCUR. ALTHOUGH THIS WAA/ASCENT WILL BE FAIRLY
WEAK...IT SHOULD BE ENOUGH TO OVERCOME SOME DRIER AIR AND ALLOW
FOR REDEVELOPMENT OF MID LEVEL CLOUDS ACROSS MUCH OF THE REGION.
ALTHOUGH NOT EXACTLY THE SAME SETUP FROM THIS MORNING...A SIMILAR
SITUATION WITH PARTLY CLOUDY/CLOUD SKIES AND SOME LIGHT SHOWERS
COULD ONCE AGAIN OCCUR...ESPECIALLY WITH SOME WEAK MID LEVEL
RIPPLES PASSING OVERHEAD AS WELL AS A LIFTING FRONTAL BOUNDARY. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT SHOWERS TONIGHT.
THUNDER SHOULD BE NONEXISTENT ONCE AGAIN AS BETTER FORCING WILL BE
TIED MORE TOWARD A STRONGER WAVE FURTHER TO THE NORTH ACROSS
WISCONSIN TONIGHT. AS THIS WAVE SHIFTS EAST OF THE REGION FRIDAY
MORNING...ANY PRECIP/CLOUD COVER WILL EXIT AND DIMINISH MAKING WAY
FOR PARTLY CLOUDY SKIES. WITH THERMAL AXIS SHIFTING
OVERHEAD...TEMPS SHOULD RISE FAIRLY EASILY TOMORROW WITH HIGH
TEMPERATURES IN THE LOWER 90S EXPECTED. WITH SOME LOCATIONS IN THE
WESTERN CWA ALREADY OBSERVING LOWER 90S TODAY...IT WOULD NOT BE
OUT OF THE QUESTION FOR SOME MID 90S TO OCCUR AS WELL. DESPITE
THIS WARM UP...LOW HUMIDITY AND SOME SUNSHINE WILL HELP TO PROVIDE
ANOTHER PLEASANT DAY. HAVE ALSO MAINTAINED LOWER 90S INTO SATURDAY
WITH REALLY NO CHANGE IN THE OVERALL SETUP EXPECTED.
THE NEXT BEST CHANCE FOR PRECIP IS STILL APPEARING TO BE LATE IN
THE WEEKEND AS A WAVE EJECTS OUT OF THE CENTRAL PLAINS. THIS
SHOULD INDUCE SOME DECENT PRESSURE FALLS AND HELP THIS SYSTEM WRAP
SOME GOOD MOISTURE INTO IT. WITH GUIDANCE STILL VARYING ON ITS
OVERALL EVOLUTION...HAVE NOT GONE TOO HIGH WITH POPS FOR SUNDAY
BUT DID INCREASE TO HIGH CHANCE POPS FOR MOST OF THE CWA ON SUNDAY
WITH MOST GUIDANCE SPEEDING UP THIS SYSTEM. THIS SYSTEM WILL NEED
TO CONTINUE BE MONITORED...DUE TO THE OVERALL STRENGTH OF THE
CONVECTIVE POTENTIAL STILL UNKNOWN AS WELL AS CHANCES FOR SOME
DECENT RAINFALL.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* PRECIP CHANCES OVERNIGHT.
KJB
//DISCUSSION...UPDATED 00Z...
OVERALL IT APPEARS TO BE A QUIET PERIOD WEATHER WISE FOR THE
TERMINALS THROUGH FRIDAY. HOWEVER...THERE IS A VERY SLIGHT CHANCE
THAT SOME ISOLATED TO WIDELY SCT -SHRA COULD DEVELOP ACROSS NORTHERN
ILLINOIS THIS EVENING AND INTO THE OVERNIGHT HOURS. THE ATMOSPHERE
ACROSS THE REGION IS WEAKLY UNSTABLE AHEAD OF AN APPROACHING WARM
FRONT ACROSS NORTH CENTRAL SECTIONS OF THE STATE. IT ALSO APPEARS
THAT A WEAK MID LEVEL DISTURBANCE ACROSS EASTERN IOWA IS PRODUCING
SOME WEAK ASCENT ACROSS PORTIONS OF NORTHERN ILLINOIS LATE THIS
AFTERNOON. THIS HAS HELPED SPARK OFF A FEW ISOLATED SHOWERS ACROSS
PUTNAM AND MARSHALL COUNTIES IN CENTRAL ILLINOIS OVER THE PAST HOUR
WITHIN THE VICINITY OF THE SURFACE FRONT. HOWEVER...DUE TO THE LOW
COVERAGE OF ANY ACTIVITY THAT AFFECTS NORTHERN ILLINOIS TONIGHT...I
HAVE OPTED TO CONTINUE A DRY FORECAST AT THE TERMINALS. ANY CLOUD
COVER THROUGH THE PERIOD WILL BE AT OR ABOVE 10,000 FEET AGL.
SOUTHERLY WINDS WILL CONTINUE THROUGH THE PERIOD AS A LARGE AREA OF
HIGH PRESSURE REMAINS ACROSS THE EASTERN CONUS...WHILE LOW PRESSURE
RESIDES ACROSS THE NORTHERN PLAINS. IT APPEARS THAT THE WINDS WILL
INCREASE DURING THE MORNING ON FRIDAY AS ATMOSPHERIC MIXING MIXES
DOWN SOME HIGHER MOMENTUM FROM ALOFT. THIS LOOKS TO RESULT IN
DAYTIME GUSTS IN THE 15 TO 20 KT RANGE.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* LOW TO MEDIUM CONFIDENCE IN WIDELY SCATTERED SHOWERS DEVELOPING
LATE TONIGHT/EARLY FRIDAY. LOW CONFIDENCE IN SHOWERS IMPACTING
TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR. WX NIL.
SUNDAY...CHANCE TSRA. OTHERWISE...VFR.
MONDAY...CHANCE TSRA EARLY. OTHERWISE...VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
229 PM CDT
A TROUGH OF LOW PRESSURE STRETCHING FROM SASKATCHEWAN TO THE
SOUTHERN HIGH PLAINS WILL REMAIN NEARLY STATIONARY THROUGH FRIDAY
NIGHT...WHILE A DEEP AREA OF LOW PRESSURE DEVELOPS WITHIN THE
NORTHERN PERIPHERY OF THIS TROUGH OVER SASKATCHEWAN. THIS LOW WILL
MOVE NORTHEAST ACROSS MANITOBA SATURDAY AND SATURDAY NIGHT...AND
OVER HUDSON BAY SUNDAY AND SUNDAY NIGHT. THIS WILL SET UP A
PROLONGED PERIOD OF SOUTH WINDS ACROSS LAKE MICHIGAN THROUGH THE
WEEKEND. WARM AIR SPREADING ACROSS THE LAKE ON THESE SOUTH WINDS
WILL TEND TO LIMIT THE DEPTH OF THE MIXED LAYER OVER THE WATER...
WITH MODEL FORECAST SOUNDINGS DEPICTING 15-20 KTS AND SOME GUSTS
INTO THE 20-25 KT RANGE PARTICULARLY OVER THE NORTHERN AND NORTH
CENTRAL PARTS OF THE LAKE. SOME GUIDANCE DEPICTS A WEAKER SURFACE
WAVE DEVELOPING ACROSS THE MIDWEST BY EARLY SUNDAY...ALONG THE COLD
FRONT TRAILING THE DEEPER CANADIAN LOW. SOUTH-SOUTHEAST WINDS MAY
BRIEFLY PICK UP NEAR 20 KTS ON THE SOUTHERN PORTION OF THE LAKE
AHEAD OF THIS WAVE EARLY SUNDAY. THE COLD FRONT WILL THEN TRANSLATE
EAST ACROSS LAKE MICHIGAN SUNDAY NIGHT...WITH THE GRADIENT WEAKENING
IN THE VICINITY OF THE FRONTAL TROUGH WITH WINDS SHIFTING TO THE
NORTH-NORTHWEST. WEAK HIGH PRESSURE WILL THEN SPREAD ACROSS THE
UPPER MIDWEST BEHIND THE FRONT SUNDAY NIGHT AND MONDAY...MOVING
ACROSS THE WESTERN AND NORTHERN LAKES MONDAY NIGHT AND TUESDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
503 AM MDT WED AUG 22 2012
.UPDATE...
ISSUED AT 412 AM MDT WED AUG 22 2012
NOSE OF HIGHER BOUNDARY LAYER RH REACHING TRIBUNE AREA WHERE
VISIBILITY AT 5SM. THIS AXIS OF HIGHER MOISTURE WITH PATCHY FOG
EXPECTED PER RUC TO MOVE SLOWLY NORTHEASTWARD THROUGH SUNRISE
BEFORE RETREATING BACK TO THE SOUTHWEST AFTER SUNRISE. HAVE GONE
AHEAD AND ADDED PATCHY FOG TO IMPACTED AREAS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS THE FORECAST
AREA THROUGH THE PERIOD AHEAD OF A LOW PRESSURE CENTER WHICH
SHOULD REACH THE AREA LATE FRIDAY THROUGH FRIDAY NIGHT. TIMING OF
THE DISTURBANCES AND THE LOW ITSELF REMAIN IN QUESTION BUT TYPICAL
AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE.
HIGH TEMPERATURES TODAY IN THE LOW TO MID 90S. SLIGHTLY COOLER
THURSDAY WITH MID 80S TO NEAR 90 IN EASTERN COLORADO...LOW 90S
ELSEWHERE. ON FRIDAY A BIT COOLER UNDER CLOUDINESS WITH MID TO
UPPER 80S.
SOUTH WINDS TODAY GENERALLY 15 TO 20 MPH WITH GUSTS TO 30 MPH
POSSIBLE ALONG/EAST OF THE CO/KS BORDER. SIMILAR WINDS THURSDAY
BUT SLIGHTLY FURTHER EAST CLOSER TO THE GOVE...LEOTI AND HILL CITY
AREAS.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SHORTWAVE TROUGH WILL COME THROUGH ON SATURDAY AND PROVIDE AMPLE
FORCING FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. FOLLOWING THIS
TROUGH AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE ROCKIES AND
PERSIST THROUGH MID-WEEK. A FEW WEAK SHORTWAVES PASS THROUGH EARLY
IN THE WEEK...BUT AT THIS POINT IT DOES NOT LOOK LIKE THERE WILL
BE ENOUGH MOISTURE OR FORCING TO TRIGGER STORMS. TEMPERATURES OVER
THE PERIOD LOOK TO BE NEAR NORMAL WITH AFTERNOON HIGHS IN THE MID
80S TO UPPER 90S...AND OVERNIGHT LOWS IN THE LOWER TO MID 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 503 AM MDT WED AUG 22 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH KGLD AND
KMCK. SOUTHERLY WINDS WILL INCREASE LATE THIS MORNING WITH GUSTS
APPROACHING 30 KTS DURING THE AFTERNOON. LATE IN THE DAY A FEW
THUNDERSTORMS MAY DEVELOP OVER EASTERN COLORADO AND APPROACH BOTH
TERMINALS BY EARLY EVENING...WITH MORE CONFIDENCE THAT STORMS
WOULD REACH GLD THAN MCK. WHILE THE DYNAMICS FOR STORMS IS
THERE...THE MOISTURE PROFILE IS MARGINAL...SO HAVE OPTED TO LEAVE
OUT ANY MENTION OF STORMS AT THIS TIME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
415 AM MDT WED AUG 22 2012
.UPDATE...
ISSUED AT 412 AM MDT WED AUG 22 2012
NOSE OF HIGHER BOUNDARY LAYER RH REACHING TRIBUNE AREA WHERE
VISIBILITY AT 5SM. THIS AXIS OF HIGHER MOISTURE WITH PATCHY FOG
EXPECTED PER RUC TO MOVE SLOWLY NORTHEASTWARD THROUGH SUNRISE
BEFORE RETREATING BACK TO THE SOUTHWEST AFTER SUNRISE. HAVE GONE
AHEAD AND ADDED PATCHY FOG TO IMPACTED AREAS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS THE FORECAST
AREA THROUGH THE PERIOD AHEAD OF A LOW PRESSURE CENTER WHICH
SHOULD REACH THE AREA LATE FRIDAY THROUGH FRIDAY NIGHT. TIMING OF
THE DISTURBANCES AND THE LOW ITSELF REMAIN IN QUESTION BUT TYPICAL
AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE.
HIGH TEMPERATURES TODAY IN THE LOW TO MID 90S. SLIGHTLY COOLER
THURSDAY WITH MID 80S TO NEAR 90 IN EASTERN COLORADO...LOW 90S
ELSEWHERE. ON FRIDAY A BIT COOLER UNDER CLOUDINESS WITH MID TO
UPPER 80S.
SOUTH WINDS TODAY GENERALLY 15 TO 20 MPH WITH GUSTS TO 30 MPH
POSSIBLE ALONG/EAST OF THE CO/KS BORDER. SIMILAR WINDS THURSDAY
BUT SLIGHTLY FURTHER EAST CLOSER TO THE GOVE...LEOTI AND HILL CITY
AREAS.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 215 AM MDT WED AUG 22 2012
A SHORTWAVE TROUGH WILL COME THROUGH ON SATURDAY AND PROVIDE AMPLE
FORCING FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. FOLLOWING THIS
TROUGH AN UPPER LEVEL RIDGE WILL BUILD IN OVER THE ROCKIES AND
PERSIST THROUGH MID-WEEK. A FEW WEAK SHORTWAVES PASS THROUGH EARLY
IN THE WEEK...BUT AT THIS POINT IT DOES NOT LOOK LIKE THERE WILL
BE ENOUGH MOISTURE OR FORCING TO TRIGGER STORMS. TEMPERATURES OVER
THE PERIOD LOOK TO BE NEAR NORMAL WITH AFTERNOON HIGHS IN THE MID
80S TO UPPER 90S...AND OVERNIGHT LOWS IN THE LOWER TO MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1126 PM MDT TUE AUG 21 2012
LIGHT SOUTHERLY WINDS AND VFR CIGS AND VIS EXPECTED OVERNIGHT
TONIGHT. THE SOUTHERLY WINDS WILL INCREASE IN SPEED BY MID
MORNING TOMORROW WITH GUSTS APPROACHING 30 KTS BY THE AFTERNOON.
LATE IN THE DAY TOMORROW THUNDERSTORMS SHOULD DEVELOP IN EASTERN
COLORADO WHICH MAY APPROACH BOTH TERMINALS TOMORROW EVENING BUT
CONFIDENCE IN TIMING AND AREAL COVERAGE IS TOO LOW THIS FAR OUT IN
TIME TO INTRODUCE IN THE TAFS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...05
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1231 AM CDT WED AUG 22 2012
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 100 PM CDT TUE AUG 21 2012
TONIGHT:
THE SHORT TERM METEOROLOGICAL CONCERN IS WHAT TO DO WITH POPS FOR THIS
EVENING. MESOSCALE (NAM, WRF) AND GLOBAL MODELS (GFS, ECMWF) PAINT DOUBT
ON CONVECTIVE PROSPECTS FOR THE EVENING. THIS IS A RESULT OF THE FACT
THAT THE UPPER LEVEL JET/WAVE IS EAST OF THE REGION AND CONVERGENCE
AT THE SURFACE IS FORECAST TO BE WEAK. 850 HPA THETA-E ADVECTION IS
FORECAST TO REMAIN WEAK AS WELL. RECENT HRRR RUNS HAS BEEN INDICATING
ISOLATED ACTIVITY ACROSS THE WESTERN ZONES THIS EVENING BUT THIS MODEL
HAS BEEN TRENDING DOWNWARD OVERALL IN THE LAST SEVERAL RUNS. AS A RESULT,
HAVE REMOVED WX FROM THE GRIDS AND GOING WITH A DRY FORECAST FOR THIS
EVENING. SOUTHERLY WINDS WILL CONTINUE THROUGH THE OVERNIGHT WITH MODERATE
DEWPOINTS AS WELL. LOOK FOR LOWS IN THE LOWER 60S DEG F.
TOMORROW:
THE LEE SURFACE TROUGH WILL STRENGTHEN TOMORROW AS MID TO UPPER LEVEL
FLOW BECOMES A BIT MORE PERPENDICULAR TO THE ROCKIES. I HAVE POPS INCREASING
UP TO THE SLIGHT CATEGORY TOWARDS 00Z TOMORROW EVENING AS WEAK 850 HPA
THETA-E ADVECTION STRENGTHENS AND SOME STORMS COULD FORM NEAR THE LEE
SURFACE TROUGH ACROSS THE W/NW ZONES. OTHERWISE, TOMORROW WILL BE MAINLY
DRY WITH HIGHS IN THE UPPER 80S TO AROUND 90 DEG F. THESE VALUES ARE
VERY CLOSE TO CLIMATOLOGY FOR THIS TIME OF YEAR. TOMORROW WILL BE A
BIT BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 204 PM CDT TUE AUG 21 2012
THIS WEEK IS SHAPING UP INTO A RELATIVELY WET PATTERN. THE UPPER
LEVEL FLOW IS EVOLVING INTO A MORE PROGRESSIVE PATTERN WITH SHORT
AND LONG WAVES TRAVELING THROUGH THE UPPER PLAINS AND MIDWEST AT A
FAIRLY REGULAR INTERVAL. WE WILL BE ON THE SOUTH END OF MINOR
WAVES, WHICH WILL OVERFLOW AFTERNOON LEE SIDE SURFACE TROUGHS DURING
THE LATE AFTERNOON AND OVERNIGHT PERIODS. THEREFORE, PRECIPITATION
CHANCES WILL BE IN THE RANGE OF 30 PERCENT WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT AS A WEAK LOBE OF VORTICITY SCRAPES WEST TO EAST
THROUGH WESTERN KANSAS. THEN ON EARLY FRIDAY, A STRONGER WAVE UP
NORTH MOVING THROUGH THE DAKOTAS WILL SWING A MORE SIGNIFICANT WAVE
THROUGH KANSAS. DURING THE TIME FROM WEDNESDAY TO FRIDAY, DEW
POINTS WILL BE INCREASING INTO THE MID 60S TO LOWER 70S, ALLOWING
THE POTENTIAL FOR SOME HEAVY RAIN IN OUR SOUTHEAST COUNTIES FRIDAY
NIGHT AND SATURDAY AS THE LOWER LAYER BECOMES MORE SATURATED. THAT
WAVE WILL NOT GO DIRECTLY THROUGH OUR FORECAST AREA, BUT WILL DRAG
SLOWLY THROUGH WESTERN KANSAS ON A NORTHWEST TO SOUTHEAST
ORIENTATION. THIS WILL ALLOW A SURFACE FRONT TO STAY NEARLY
ANCHORED OVER OUR CENTRAL TO SOUTHEASTERN ZONES, AND SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO RE-FIRE ALONG AND SOUTHEAST OF THE
FRONTAL BOUNDARY. POPS WILL BUMP UP INTO THE 40 TO 50 PERCENT
RANGE, FOR SOME OF OUR EASTERN ZONES, WITH 60 PERCENT POPS FRIDAY
NIGHT AND AGAIN SATURDAY NIGHT ACROSS OUR SOUTHEASTERN ZONES,
SOUTHEAST OF A LINE FROM LARNED TO MEADE. DECIDED TO NOT GO AS HIGH
AS THE ECMWF MODEL IS FORECASTING THE QPF TO BE (ABOUT 4 INCHES
TOTAL QPF WED TO SUN) SOUTHEAST OF A PRATT TO ASHLAND LINE, BUT
NEARER THE 2 INCH RANGE, WHICH IS CLOSER TO THE GFS OUTPUT. THE
WAVE WILL BE NEARLY EXITING OUR EASTERN CWA BY SUNDAY, BUT SMALL 20
PERCENT POPS WILL LINGER SUNDAY MORNING ACROSS OUR EXTREME EASTERN
ZONES. AN UPPER LEVEL RIDGE WILL BUILD IN FROM THE SOUTH MONDAY,
AND SHOULD KEEP BOTH MONDAY AND TUESDAY DRY.
MAXIMUM TEMPERATURES WEDNESDAY AND THURSDAY WILL REACH THE NEAR 90F
RANGE, BUT THEN A COLD FRONT MOVING IN FRIDAY WILL BRING CLOUDS AND
PRECIPITATION TO HELP LOWER MAX T`S INTO THE MIDDLE TO UPPER 80S
SATURDAY. MAX TEMPS WILL BASICALLY STAY IN THE 80S SUNDAY AS WELL,
THEN BEGIN REBOUNDING UPWARD MONDAY AND TUESDAY INTO THE LOWER 90S.
WINDS DO NOT LOOK TO BE TOO STRONG THROUGH THE WED NT THROUGH TUE
PERIOD, BUT WILL MAINTAIN A SOUTHERLY FLOW SUNDAY INTO TUESDAY.
MINIMUM TEMPERATURES IN THE LOWER TO MIDDLE 60S THURSDAY WILL RISE
TO THE MIDDLE 60S NORTHWEST TO LOWER TO MID 70S SOUTHEAST FRIDAY,
SATURDAY, SUNDAY, MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1228 AM CDT WED AUG 22 2012
VFR CONDITIONS WILL PREVAIL WITH MOSTLY CLEAR SKIES ANTICIPATED
THROUGHOUT THE DAY. DEVELOPING LEE TROUGHING ACROSS EASTERN
COLORADO WILL ALLOW SOUTHERLY WINDS TO CONTINUE AROUND 10 KNOTS
THROUGH THE EARLY MORNING HOURS. A FEW GUSTS AROUND 20 KNOTS WILL
BE POSSIBLE STARTING LATE TOMORROW MORNING AS THE ATMOSPHERE MIXES
AND THE PRESSURE GRADIENT TIGHTENS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 91 67 86 / 30 30 30 30
GCK 64 92 66 88 / 30 30 20 20
EHA 63 91 66 88 / 20 30 20 30
LBL 64 91 67 87 / 30 30 30 30
HYS 65 92 67 87 / 30 30 30 20
P28 66 90 69 84 / 30 30 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1029 PM EDT THU AUG 23 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE MOSTLY DRY AND COMFORTABLE CONDITIONS
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
03Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO INCREASE CLOUD
COVERAGE ACROSS THE WV/MD RIDGES.
THE LATEST RAP MID-LEVEL AND SAT WV IMAGERY ANALYSIS INDICATES A
SWATH OF DRY AIR EXTENDING ACROSS THE UPPER OHIO VALLEY WITH
MOISTURE CONFINED TO THE SOUTHEAST US COAST AT THE BASE OF A 500MB
TROUGH. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE EXTENDS FROM
THE OHIO VALLEY INTO THE NORTHEAST.
OVERNIGHT...HIGH PRESSURE AND DRY AIR ALOFT WILL CONTINUE TO
DOMINATE THE REGION. RADIATIONAL COOLING WILL ALLOW FOR PATCHY FOG
TO DEVELOP NEAR DAWN, ESPECIALLY ALONG THE RIVER VALLEYS WHERE
WARMER WATER AT THE SURFACE IS MORE CONDUCIVE TO DEVELOPMENT. FOR
TEMPS, LOWS ARE FAIRLY CLOSE TO LAMP GUIDANCE, IN THE MID TO UPPER
50S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
BROAD HIGH PRESSURE WILL PROVIDE MAINLY DRY CONDITIONS ACROSS THE
UPPER OHIO VALLEY INTO SUNDAY.
ONLY POTENTIAL FOR PRECIPITATION APPEARS TO BE SOME ISOLATED
AFTERNOON SHOWERS OR THUNDERSTORMS OVER THE RIDGES OF WV AND MD
LATE FRIDAY AND EASTERN COUNTIES SATURDAY AFTERNOON. LATEST
MODEL OUTPUT IS IN GOOD AGREEMENT SHOWING AN UPPER LEVEL WAVE
ROTATING IN FROM THE EAST OVER THE MID-ATLANTIC LATE FRIDAY
THROUGH THE WEEKEND.
PER BLEND OF RECENT GFS AND NAM MOS, CONTINUED FORECAST OF
AFTERNOON HIGH TEMPERATURES TO BE WARMER THAN NORMAL THIS PERIOD,
WHILE EARLY MORNING LOWS WILL BE CLOSE TO NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE LONG TERM FORECAST WAS CONSTRUCTED USING MODIFIED HPC GUIDANCE
ONCE AGAIN, AS THOSE NUMBERS ARE REFLECTIVE OF A COMPROMISE BETWEEN
GFS AND ECMWF MODELS IN DEPICTIONS OF AN UPPER TROUGH/COLD FRONT
APPROACH/PASSAGE ACROSS THE UPPER OHIO VALLEY EARLY NEXT WEEK.
INTERACTION OF THAT SYSTEM WITH THE REMNANTS OF THE TROPICAL
SYSTEM ISSAC MAY IMPACT THE REGION DURING THE LATTER HALF OF THE
WEEK.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
WITH EXCEPTION OF EARLY MORNING FOG...VFR CONDITIONS AND LIGHT
WIND CAN BE EXPECTED THROUGH THE TAF PERIOD AS HIGH PRES SLIDES
ACROSS THE REGION.
.OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE TO PREVAIL THROUGH THE WEEKEND. WITH
THE EXCEPTION OF MORNING FOG AREAS...RESTRICTION POTENTIAL WILL
INCREASE EARLY NEXT WEEK AS A COLD MOVES TOWARD THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
802 PM EDT THU AUG 23 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE MOSTLY DRY AND COMFORTABLE CONDITIONS
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
00Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO REMOVE
THUNDERSTORM WORDING IN TUCKER COUNTY AS CONVECTION DIMINISHES. NO
CHANGES TO THE GRIDS OTHERWISE.
THE LATEST RAP MID-LEVEL AND SAT WV IMAGERY ANALYSIS INDICATES A
SWATH OF DRY AIR EXTENDING ACROSS THE UPPER OHIO VALLEY WITH
MOISTURE CONFINED TO THE SOUTHEAST US COAST AT THE BASE OF A 500MB
TROUGH. AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE EXTENDS FROM
THE OHIO VALLEY INTO THE NORTHEAST. CONVECTION ACROSS THE WV RIDGES
HAS DIMINISHED WITH THE LOSS OF DIURNAL HEATING THIS EVENING AND
THERE ARE A FEW CUMULUS LINGERING THERE. OTHERWISE, THERE ARE
CLEAR SKIES ACROSS THE AREA.
OVERNIGHT...HIGH PRESSURE AND DRY AIR ALOFT WILL CONTINUE TO
DOMINATE THE REGION. RADIATIONAL COOLING WILL ALLOW FOR PATCHY FOG
TO DEVELOP NEAR DAWN, ESPECIALLY ALONG THE RIVER VALLEYS WHERE
WARMER WATER AT THE SURFACE IS MORE CONDUCIVE TO DEVELOPMENT. FOR
TEMPS, LOWS ARE FAIRLY CLOSE TO LAMP GUIDANCE, IN THE MID TO UPPER
50S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
BROAD HIGH PRESSURE WILL PROVIDE MAINLY DRY CONDITIONS ACROSS THE
UPPER OHIO VALLEY INTO SUNDAY.
ONLY POTENTIAL FOR PRECIPITATION APPEARS TO BE SOME ISOLATED
AFTERNOON SHOWERS OR THUNDERSTORMS OVER THE RIDGES OF WV AND MD
LATE FRIDAY AND EASTERN COUNTIES SATURDAY AFTERNOON. LATEST
MODEL OUTPUT IS IN GOOD AGREEMENT SHOWING AN UPPER LEVEL WAVE
ROTATING IN FROM THE EAST OVER THE MID-ATLANTIC LATE FRIDAY
THROUGH THE WEEKEND.
PER BLEND OF RECENT GFS AND NAM MOS, CONTINUED FORECAST OF
AFTERNOON HIGH TEMPERATURES TO BE WARMER THAN NORMAL THIS PERIOD,
WHILE EARLY MORNING LOWS WILL BE CLOSE TO NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE LONG TERM FORECAST WAS CONSTRUCTED USING MODIFIED HPC GUIDANCE
ONCE AGAIN, AS THOSE NUMBERS ARE REFLECTIVE OF A COMPROMISE BETWEEN
GFS AND ECMWF MODELS IN DEPICTIONS OF AN UPPER TROUGH/COLD FRONT
APPROACH/PASSAGE ACROSS THE UPPER OHIO VALLEY EARLY NEXT WEEK.
INTERACTION OF THAT SYSTEM WITH THE REMNANTS OF THE TROPICAL
SYSTEM ISSAC MAY IMPACT THE REGION DURING THE LATTER HALF OF THE
WEEK.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
WITH EXCEPTION OF EARLY MORNING FOG...VFR CONDITIONS AND LIGHT
WIND CAN BE EXPECTED THROUGH THE TAF PERIOD AS HIGH PRES SLIDES
ACROSS THE REGION.
.OUTLOOK /FRIDAY NIGHT THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE TO PREVAIL THROUGH THE WEEKEND. WITH
THE EXCEPTION OF MORNING FOG AREAS...RESTRICTION POTENTIAL WILL
INCREASE EARLY NEXT WEEK AS A COLD MOVES TOWARD THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1102 AM EDT WED AUG 22 2012
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL MOVE EASTWARD PAST THE MOUNTAINS BY
THIS EVENING LEAVING THE UPPER OHIO VALLEY DRY AND POSSIBLY
GIVING A SHOWER OR ISOLATED THUNDERSTORM OVER THE RIDGES THIS
AFTERNOON. HIGH PRESSURE WILL FOLLOW WITH DRY CONDITIONS THROUGH
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT VISIBLE SATELLITE AND SURFACE DATA SHOW THE FOG HAS DISSIPATED
AND HAS GIVEN WAY TO A CLEAR SKY WITH THE EXCEPTION OF A FEW
CLOUDS OVER THE EXTREME SOUTHEAST FA.
WATER VAPOR IMAGERY SHOWS UPPER LOW LEVEL PRESSURE TROUGH MOVING
EASTWARD THROUGH SOUTHWEST PENNSYLVANIA AND CURRENT MESOSCALE
ANALYSIS SHOWS COLDEST AIR AT 500MB OF -16C SHIFTING EAST INTO
CENTRAL PA AND SHOULD EXIT PAST THE MOUNTAINS BEFORE EVENING. SO
ONLY LEFT A CHANCE OF AFTERNOON ISOLATED THUNDERSTORMS FOR THE
MOUNTAINS, WHERE CONVECTIVE TEMPERATURES SHOULD HAVE TO REACH THE
MID 70S BEFORE ANY SHOWERS OR THUNDERSTORMS FORM, WHICH IS
SUPPORTED BY RECENT HRRR MODEL OUTPUT.
OTHERWISE, PLENTY OF SUNSHINE TODAY WITH FORECASTED HIGHS USING
GFS/NAM BLEND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
HEIGHTS WILL BEGIN TO SLOWLY RISE THU, AND A WEAK RIDGE WILL
BUILD IN OVER THE UPPER OHIO VALLEY THROUGH FRIDAY. AT THE SFC,
WEAK SFC HIGH WILL VERY SLOWLY MOVE ACROSS THE REGION THROUGH THE
END OF THE WORK WEEK. DAYTIME TEMPS WILL RISE A BIT DURING THE
SHORT TERM.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND, WITH SFC HIGH
AND UL RIDGE HOLDING OVER THE OHIO VALLEY. MODEL SOLUTIONS BEGIN
TO DISPERSE EARLY NEXT WEEK. BECAUSE OF LOW CONFIDENCE AND
INCONSISTENCY FROM RUN TO RUN, WILL MAKE VERY FEW CHANGES TO LONG
TERM PERIOD.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR WEATHER CAN BE EXPECTED INTO TONIGHT AS HIGH PRES BLDS OVR THE
UPR OH VALLEY REGION. EXPECT RIVER VALLEY FOG TO DVLP ONCE AGAIN IN
THE PREDAWN OF THURSDAY MORNING...WHICH MAY CAUSE A BRIEF PERIOD OF
IFR.
.OUTLOOK/ THURSDAY THROUGH SUNDAY/...
VFR PREDOMINATE...EXCEPT FOR POSSIBLE RESTRICTIONS DUE TO EARLY
MORNING RIVER VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
808 AM EDT WED AUG 22 2012
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL MOVE EASTWARD PAST THE MOUNTAINS BY
EVENING. SO MOST OF THE UPPER OHIO VALLEY WILL SEE NO RAIN, WHILE A
SHOWER OR STORM IS POSSIBLE OVER THE RIDGES THIS AFTERNOON.
HIGH PRESSURE WILL FOLLOW WITH DRY CONDITIONS THROUGH THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT SATELLITE AND SURFACE DATA SHOW THE FOG MAINLY CONFINED TO
RIVER VALLEYS, SO EXPECT THE FOG TO DISSIPATE BEFORE 10 AM.
SATELLITE DATA SHOWS UPPER LOW LEVEL PRESSURE TROUGH MOVING
EASTWARD THROUGH SOUTHWEST PENNSYLVANIA, AND SHOULD EXIT PAST THE
MOUNTAINS BEFORE EVENING. SO ONLY LEFT A CHANCE OF AFTERNOON
THUNDERSTORMS FOR THE MOUNTAINS, WHERE CONVECTIVE TEMPERATURES
SHOULD HAVE TO REACH THE MID 70S BEFORE ANY SHOWERS OR THUNDERSTORMS
FORM, WHICH IS SUPPORTED BY RECENT HRRR MODEL OUTPUT.
OTHERWISE, PLENTY OF SUNSHINE TODAY WITH FORECASTED HIGHS CLOSER
TO GFS MOS VALUES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
HEIGHTS WILL BEGIN TO SLOWLY RISE THU, AND A WEAK RIDGE WILL
BUILD IN OVER THE UPPER OHIO VALLEY THROUGH FRIDAY. AT THE SFC,
WEAK SFC HIGH WILL VERY SLOWLY MOVE ACROSS THE REGION THROUGH THE
END OF THE WORK WEEK. DAYTIME TEMPS WILL RISE A BIT DURING THE
SHORT TERM.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND, WITH SFC HIGH
AND UL RIDGE HOLDING OVER THE OHIO VALLEY. MODEL SOLUTIONS BEGIN
TO DISPERSE EARLY NEXT WEEK. BECAUSE OF LOW CONFIDENCE AND
INCONSISTENCY FROM RUN TO RUN, WILL MAKE VERY FEW CHANGES TO LONG
TERM PERIOD.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
REMAINING IFR RIVER VALLEY FOG WILL DISSIPATE BEFORE 14Z. EXPECT
VFR THE REST OF TODAY AND EARLY TONIGHT.
EXPECT RIVER VALLEY FOG TO DEVELOP AGAIN EARLY THURSDAY MORNING,
WHICH CAUSE A PERIOD OF MVFR FOG AND STRATUS AT MOST TAF SITES
09Z-13Z, AND PERHAPS A SHORT PERIOD OF IFR.
.OUTLOOK/ THURSDAY THROUGH SUNDAY/...
MAINLY VFR, EXCEPT FOR POSSIBLE RESTRICTIONS DUE TO EARLY MORNING
RIVER VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 AM EDT WED AUG 22 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR TROF OVER ERN CAN/NE CONUS THAT IS SLOWLY
LIFTING OUT AND AN UPR RDG IN THE ROCKIES/PLAINS. SFC HI PRES
CENTERED OVER SW WI/LGT WLY FLOW ON ITS NRN FLANK AS WELL AS VERY
DRY AIR SHOWN ON THE 12Z INL/MPX RAOBS ARE BRINGING A TRANQUIL DRY
DAY TO UPR MI. THE ONLY FLY IN THE OINTMENT IS SOME MAINLY HI CLDS
DRIFTING SEWD INTO MAINLY THE E HALF OF THE CWA. THESE CLDS ARE ON
THE SRN FLANK OF AREA OF THICKER CLDS/A FEW -SHRA OVER ONTARIO
ASSOCIATED WITH DEEPER MSTR DEPICTED ON THE 12Z YPL RAOB AND WAD IN
ADVANCE OF SHRTWV EMBEDDED IN NW FLOW ALF AND NOW MOVING INTO FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU WED WL BE PCPN CHCS ASSOCIATED WITH SHRTWV
FCST TO DROP SEWD THRU ONTARIO.
TNGT...SHRTWV NOW MOVING INTO FAR NW ONTARIO AND ASSOCIATED SFC LO
IS PROGGED TO DRIFT SEWD TO JUST W OF JAMES BAY BY 12Z WED.
ATTENDANT SFC TROF IS FCST TO STRETCH FM SFC LO WSWD THRU NRN LK SUP
TO NEAR ISLE ROYALE. THE EXPECTED MOTION OF THE SHRTWV INDICATES
BEST DPVA/DEEPER DEEP LYR QVECTOR CNVGC WL REMAIN FOCUSED IN ONTARIO.
ANOTHER SIGNIFICANT DETRIMENT TO PCPN CHCS WL BE VERY DRY LLVL AIR
SHOWN ON THE 12Z MPX/INL RAOBS AS INCRSG LLVL WSW FLOW TO THE S OF
SFC-H85 TROF WL BE DRAWING THIS AIR TOWARD UPR MI. SO ALTHOUGH
MODELS SHOW AN EXPANDING AREA OF H7 MSTR RELATED TO ISENTROPIC
ASCENT ON THE 305K SFC...NAM FCST SDNGS INDICATE THIS MOISTER LYR WL
BE RATHER THIN AND CAP MUCH DRIER LLVLS. THE GFS SHOWS MORE LLVL
MSTR...BUT WL TEND TO FOLLOW THE NAM GUIDANCE CONSIDERING THE
DRYNESS OF THE LLVLS OBSVD UPSTREAM. FOR THESE REASONS...OPTED TO GO
DRY TNGT AND LIMIT SCHC POPS ONLY TO THE FAR NRN CWA NEAR INCOMING
SFC TROF. OTRW...INCRSG WSW FLOW WL TEND TO LIMIT THE DIURNAL TEMP
FALL...ESPECIALLY IN DOWNSLOPE AREAS NEAR LK SUP THAT WL ALSO SEE
MORE AC RELATED TO H7 MOISTENING OVERNGT.
WED...SHRTWV TO THE NE IS PROGGED TO SLIDE TO THE E...TAKING DEEP
LYR QVECTOR CNVGC/H7 MSTR WITH IT. IN THE ABSENCE OF SGNFT MID LVL
FORCING AND WITH LLVL DRY AIR LINGERING TO THE S OF SFC LO PRES
TROF...THINK PCPN CHCS ARE MINIMAL. ALTHOUGH THE 12Z GFS GENERATES
SOME SPOTTY LGT QPF OVER PORTIONS OF MAINLY THE NCNTRL AND E...
OPTED TO FOLLOW THE BULK OF OTHER GUIDANCE AND KEEP THE LAND CWA
DRY...WITH SCHC POPS RESTRICTED TO NE LK SUP...CLOSER TO MID LVL
FORCING/MSTR. WITH H85 TEMPS PROGGED TO PEAK FM ARND 15C OVER THE E
TO 17C OVER THE W...EXPECT A WARMER DAY. DEEP MIXING ON NAM FCST
SDNGS SUG HI TEMPS WL REACH THE MID 80S OVER THE INTERIOR. A
WEAKENING PRES GRADIENT IN THE AFTN WL ALLOW FOR LK BREEZES TO FORM
AND MODERATE TEMPS NEAR THE LKSHORES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
WEDNESDAY NIGHT...
WILL BEGIN WITH NW FLOW ALOFT AT 00Z THURSDAY /AND A WEAK SFC FRONT
NEARLY STATIONARY W TO E OVER THE CWA/...WITH A WEAK 500MB RIDGE SET
UP ALONG THE RED RIVER VALLEY OF THE N. EXPECT THIS RIDGE TO PUSH
ACROSS THE UPPER GREAT LAKES THURSDAY MORNING INTO THE EARLY
AFTERNOON HOURS...BEFORE GETTING PUSHED E /THANKS THE TO THE E
MOTION OF THE CURRENT TROUGH SET UP LONG THE PACIFIC COAST/. WEAK S
FLOW SHOULD HELP KEEP TEMPS ROUGHLY 5F WARMER THAN TONIGHT.
THURSDAY AFTERNOON THROUGH FRIDAY NIGHT...
LOOK FOR THE N EXTENT OF THE PACIFIC TROUGH TO PUSH ACROSS THE
DAKOTAS THURSDAY MORNING...AND ACROSS THE UPPER GREAT LAKES THURSDAY
AFTERNOON INTO THURSDAY NIGHT. FCST MODELS ARE PRETTY CONSISTENT IN
HAVING THE TROUGH DIRECTLY OVERHEAD AT 18Z FRIDAY...BEFORE SHIFTING
NE TO ONTARIO AND W QUEBEC. THE MAIN CONCERN WOULD STILL BE SLIGHTLY
STRONGER S WINDS FRIDAY MORNING W INTO THE AFTERNOON HOURS E.
SATURDAY THROUGH SUNDAY...
A STRONGER 500MB LOW WILL POSITION ITSELF OVER S SASKATCHEWAN
SATURDAY MORNING...AND CENTRAL MANITOBA BY 06Z SUNDAY. THE NEARLY
STACKED SYSTEM SHOULD RESULT THE FRONTAL BOUNDARY OVER THE CWA
LIFTING N AS A WARM FRONT...AND WARMER AIR SURGING N FOR
SATURDAY...WITH WIDESPREAD 80 DEGREE TEMPS AS 850MB TEMPS PUSH INTO
THE 16-18C RANGE. MUCH OF THE CLOUD COVER AND PRECIP SHOULD SHOULD
REMAIN W...CLOSER TO THE NEARING COLD FRONT ACROSS E ND AND W MN.
THE 21/00Z CANADIAN MODEL...WHILE HAVING A SIMILAR IDEA...IS ON THE
NORTHERN FRINGE OF SOLUTIONS. ON THE OTHER HAND...THE 21/06Z GFS IS
A BIT FARTHER SOUTH. THE DIFFERENCE FROM THE 2 IS ROUGHLY
200MI...WHICH IS NOT TOO BAD FOR A 120HR OR MORE FCST. THESE
DIFFERENCES BECOME A BIT MORE PRONOUNCED ACROSS S HUDSON BAY/N
ONTARIO SUNDAY NIGHT...BUT SHOULD NOT IMPACT OUR FCST TOO
GREATLY...AS A TROUGH WILL CONTINUE TO DOMINATE THE UPPER GREAT
LAKES REGION /SATURDAY NIGHT THROUGH AT LEAST SUNDAY NIGHT/.
MONDAY AND TUESDAY...
WRAP AROUND MOISTURE WILL BE POSSIBLE WITH COOLER AIR SLIDING IN ON
NW WINDS OFF THE GFS. HOWEVER...THIS IS HIGHLY DEPENDENT ON WHERE
THE STILL RELATIVELY STACKED LOW DECIDES TO GO. THE MORE PROGRESSIVE
N LOW OFF THE ECMWF STILL TRIES TO AMPLIFY THE SYSTEM TO OUR S
/ACROSS MO/IA/IL/WI/...WITH ANOTHER ROUND OF SHOWERS AND POSSIBLY TS
MONDAY MORNING AND AFTERNOON MAINLY CENTRAL AND E.
THE 21/00Z ECMWF AND 06Z GFS BECOME COMPLETELY OUT OF PHASE OVER THE
PACIFIC NW BY 00Z SUNDAY WRT THE 500MB PATTERN. LUCKILY THIS DOES
NOT SEEM TO NEGATIVELY IMPACT THE UPPER GREAT LAKES REGION UNTIL
MONDAY AFTERNOON/EVENING. AS A RESULT OF AN EXTREMELY LOW CONFIDENCE
FORECAST BEYOND MONDAY...WILL NOT TRY TO DO TOO MUCH OVER CLIMO. BY
DAYBREAK TUESDAY THE GFS HAS A SIZABLE TROUGH ACROSS THE GREAT
LAKES...WHILE THE ECMWF SHIFTS A HIGH AMPLITUDE RIDGE OVERHEAD. THE
MAIN CONCERN WITH A SOLID MODEL BLEND WOULD BE THE ISSUES PRODUCED
BY THE GFS AND CONVECTIVE FEEDBACK. ON A POSITIVE NOTE...THE 12Z
GFS/ECMWF DO LOOK A LITTLE MORE IN AGREEMENT FOR MONDAY AND
TUESDAY...WITH A RIDGE BUILDING IN MONDAY NIGHT INTO TUESDAY. WILL
SEE IF THIS TREND HOLDS UP WITH THE 18Z GFS AND 00Z RUNS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 121 AM EDT WED AUG 22 2012
NO CHANGES TO EXPECTED CONDITIONS SINCE PREVIOUS DISCUSSION BELOW...
WITH RELATIVELY DRY LOW-LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THIS FCST PERIOD AT KIWD/KCMX/KSAW. MODEST LOW-LEVEL JET ARRIVING
OVERNIGHT TONIGHT WILL LEAD TO POSSIBLE LLWS...MAINLY AT KCMX AND
KIWD WHICH WILL BE CLOSER TO AXIS OF SPEED MAX. WITH DAYTIME HEATING
ON WED...THESE STRONGER WINDS WILL MIX OUT AND RESULT IN GUSTY WSW
WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT TUE AUG 21 2012
EXPECT SW WINDS VEERING W TO INCREASE UP TO 25 KTS LATER TONIGHT/
EARLY WED...STRONGEST IN THE AREA BETWEEN THE KEWEENAW AND ISLE
ROYALE WHERE TERRAIN ACCENTUATES THIS FLOW...AS A LO PRES TROF
PRESSES INTO LAKE SUPERIOR FROM ONTARIO. LIGHT WINDS WILL THEN
PREVAIL FROM WED AFTERNOON INTO THE WEEKEND BEFORE THE APPROACH OF A
STRONGER DISTURBANCE/COLD FRONT MIGHT CAUSE S-SW WINDS TO INCREASE
UP TO 25 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
300 PM CDT WED AUG 22 2012
.DISCUSSION...
NO OBVIOUS FOR ISOLATED STORM DEVELOPMENT SHOWING ON RADAR OR VSBY
SATELLITE. WATER VAPOR AND THE RAP MODEL INDICATE A MID LEVEL DISTURBANCE
NEAR KSLC. THIS DISTURBANCE IS PROGGED BY ALL MODELS TO BEGIN
AFFECTING THE FCST AREA THURSDAY AFTERNOON SO RAIN CHANCES THIS
EVENING...ALBEIT ISOLATED...LOOK UNCERTAIN AT THIS TIME. NOTE THAT
THE RAP IS POOLING CONSIDERABLE MOISTURE ACROSS SWRN LATE TONIGHT.
THE COULD RAISE THE PROSPECT OF STRATUS BUT NON IS INDICATED BY 12Z
AT KMCK.
THUS THE FCST TURNS TO THURSDAY AFTERNOON. THE NAM AND GEM BRING
A WEAK COLD FRONT THROUGH THE FCST AREA OVERNIGHT. NEITHER THE GFS
NOR THE ECM SHOW THIS FEATURE. THEY INSTEAD WASH THE FRONT OUT
NEAR THE SOUTH DAKOTA BORDER AND MAINTAIN A BELT OF STRONG
SOUTHWEST WINDS FARTHER WEST DURING THE DAY THURSDAY. BY THIS TIME
THE DISTURBANCE CURRENTLY ACROSS NRN UT SHOULD BE OPERATING ACROSS
KS AND SRN NEB. ALL MODELS SUGGEST A HEAVY RAIN CENTER WILL
DEVELOP THURSDAY NIGHT THROUGH FRIDAY...SOMEWHERE ACROSS KS. THE
NAM WAS THE FARTHEST NORTH PRODUCING 1.8 INCHES NEAR NORTON KS.
THE 12Z GFS INDICATED 11 INCHES OVER KHLC. THE ECM AROUND 2.5 NEAR
KP28 AND THE SREF HAD 1.35 NEAR KGLD. ALL OF THESE SOLNS WERE
BLENDED TOGETHER TO PRODUCE CHC POPS ACROSS SWRN AND SCNTL NEB. BY
FRIDAY MORNING MOST SOLNS SHOW A CLOSE 500 MB LOW FORMING OVER KS
AND IT APPEARS THE MODELS ARE TAKING PIECES OF THE DEEP SWRN U.S.
UPPER LEVEL LOW ACROSS THE ROCKIES AND RECONSOLIDATING IT OVER
KS.
SO THE FCST FOLLOWS THESE SOLNS AND PARTS OF THE FCST AREA WILL BE
ON THE PERIPHERY OF WHAT COULD BECOME A LARGE COMPLEX OF SHOWERS
AND THUNDERSTORMS LATE THURSDAY THROUGH FRIDAY. A POWERFUL NRN
STREAM DISTURBANCE WILL TRACK ALONG THE CANADIAN BORDER FRIDAY
NIGHT AND SATURDAY AND THIS SHOULD OPEN UP THE CLOSED KS LOW AND
SHEAR IT OUT TO THE EAST SOMETIME DURING THE DAY SATURDAY.. A
SIGNIFICANT COLD FRONT WILL SWEEP SOUTH THROUGH THE FCST AREA
SATURDAY PRODUCING HIGHS IN THE 80S WITH DRY CONDITIONS.
SUNDAY THROUGH WEDNESDAY...DRY WEATHER IS EXPECTED. THE DROUGHT
RIDGE WILL GRADUALLY BUILD NORTH TOWARD THE CNTL PLAINS AND
ANOTHER STRONG NORTHERN STREAM LOW WILL BEGIN TRACKING ALONG THE
CANADIAN BORDER. THIS SHOULD SPAWN A HIGH PLAINS LOW PRESSURE
SYSTEM AND DRAW WARM AIR BACK NORTH. TEMPS SHOULD RISE BACK INTO
THE LOW TO MID 90S NEXT WEEK. A COLD FRONT SHOULD MOVE THROUGH
LATE TUESDAY OR WEDNESDAY FOR COOLER HIGHS WEDNESDAY .
TEMPERATURES THURSDAY AND FRIDAY ARE A COMPLEX BLEND OF BIAS
CORRECTED MODEL DATA AND GUIDANCE. THE MODELS ARE FCSTING DEEP
MOISTURE AND STRATUS FRIDAY AND SATURDAY MORNINGS WHICH COULD HAVE
A BIG IMPACT ON HIGH TEMPERATURES.
&&
.AVIATION...
GUSTY SOUTHERLY WINDS WILL IMPACT MUCH OF WESTERN NEBRASKA THROUGH
THIS EVENING. MAY SEE GUSTS BACK OFF A BIT LATER THIS EVENING...BUT
WITH A TIGHT PRESSURE GRADIENT SHOULD STAY FAIRLY BREEZY
THROUGH THE OVERNIGHT HOURS. ALSO OF CONSIDERATION...THE LOW LEVEL
JET WILL PICK UP THIS EVENING...WITH SOUNDINGS INDICATING WINDS JUST
ABOVE THE SURFACE OF 40KTS. THINK WITH SURFACE WINDS STAYING
HIGHER...LOW LEVEL WIND SHEAR IS NOT NEEDED AT THIS TIME. SCATTERED
TO BROKEN CLOUD COVER IS EXPECTED THROUGH THE PERIOD...HOWEVER
CEILINGS WILL REMAIN VFR. ALSO...THERE IS POTENTIAL FOR
THUNDERSTORMS TO DEVELOP INTO THE EVENING OVER THE PANHANDLE AND
INTO NORTHWEST NEBRASKA. THE HIGHEST PROBABILITY FOR
ANY STORMS WILL BE WEST OF A LINE FROM KOGA TO KTIF TO KANW.
CONFIDENCE IS LOW ON COVERAGE OF ANY ACTIVITY THIS AFTERNOON...OR
HOW FAR EAST IT WILL MAKE IT SO JUST INCLUDED A VCTS INTO THE KVTN
TAF FOR THIS ISSUANCE.
&&
.FIRE WEATHER...
AS FUELS REMAIN VERY DRY...CONDITIONS THROUGH THE REMAINDER OF THIS
AFTERNOON WILL BE CRITICAL OR NEAR CRITICAL ACROSS MUCH OF WESTERN
AND NORTH CENTRAL NEBRASKA WITH RELATIVE HUMIDITY NEAR 20 PERCENT
AND GUSTY WINDS. FOR FIRE ZONE 209...A RED FLAG WARNING WILL
CONTINUE THROUGH 8 PM CDT.
WINDS WILL STAY BREEZY AND CONTINUE TO GUST TO 25 MPH OR HIGHER THIS
EVENING DUE TO A TIGHT PRESSURE GRADIENT AND STRONG WINDS ALOFT
MIXING DOWN TO THE SURFACE. THESE WINDS WILL DIMINISH SLIGHTLY INTO
THURSDAY MORNING...WITH GUSTS ON THURSDAY EXPECTED TO BE LESSER
ACROSS THE DISTRICTS. IN TERMS OF HUMIDITY...COOLING TEMPERATURES
THIS EVENING WILL CAUSE THE AIR TO BECOME MORE HUMID...WHICH WILL
ALLEVIATE THE DISTRICTS FROM THE CRITICAL FIRE WEATHER CONDITIONS.
IN ADDITION...THERE IS POTENTIAL FOR THUNDERSTORMS ALONG AND WEST OF
A LINE FROM OGALLALA TO THEDFORD TO AINSWORTH THIS EVENING. ANY
THUNDERSTORMS WILL HAVE THREATS ERRATIC AND GUSTY WINDS AND DRY
LIGHTNING...AS THE BOUNDARY LAYER IS VERY DRY. BELIEVE ANY STORMS
WILL BE ISOLATED IN NATURE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 8 PM CDT
THIS EVENING FOR NEZ209.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1225 AM CDT WED AUG 22 2012
.AVIATION...
SOUTHERLY WINDS WILL STAY UP OVER NIGHT AND INCREASE THROUGH THE DAY
ON WEDNESDAY AHEAD OF SURFACE LOW PRESSURE SYSTEM MOVING ACROSS
WESTERN SOUTH DAKOTA. ISOLATED HIGH BASED THUNDERSTORMS ARE EXPECTED
OVER THE NEBRASKA PANHANDLE WEDNESDAY AFTERNOON SPREADING EAST INTO
NORTHERN NEBRASKA OVERNIGHT. WINDS WILL BE STRONG AND ERRATIC IN THE
VICINITY OF THUNDERSTORMS. DUE TO THE ISOLATED NATURE OF THE
THUNDERSTORMS DO NOT HAVE THE CONFIDENCE TO INCLUDE THEM IN ANY OF
THE TERMINAL FORECASTS.
&&
.PREV DISCUSSION... /ISSUED 623 PM CDT TUE AUG 21 2012/
UPDATE...
DISCUSSION...
RADAR INDICATES ISOLATED THUNDERSTORMS MAY BE DEVELOPING A BIT
FARTHER NORTH THAN FCST BY THE HRRR. SO A MINOR ADJUSTMENT FOR
ISOLATED EVENING TSTMS HAS BEEN MADE ACROSS FAR SOUTHERN
NEBRASKA.
PREV DISCUSSION... /ISSUED 332 PM CDT TUE AUG 21 2012/
DISCUSSION...
AN AREA OF WEAK CU IS FORMING ACROSS FAR SW NEB THIS AFTERNOON.
THE HRRR SUGGEST ISOLATED STORM DEVELOPMENT WITH STORM MOTION
SOUTHEAST AND AWAY FROM THE FCST AREA. OTHERWISE NO SIGNIFICANT
WEATHER IS EXPECTED OVERNIGHT. LOW PRESSURE ACROSS THE NRN HIGH
PLAINS AND A WARM FRONT STRETCHING ACROSS NRN NEB SHOULD KEEP MIN
TEMPS WARMER TONIGHT. THE SFC LOW IS EXPECTED TO BEGIN MOVING
SLOWLY SOUTH OVERNIGHT.
ON WEDNESDAY...THE LOW DROPS SOUTH TOWARD SWRN SD AND NW NEB BY
LATE AFTERNOON. MOISTURE ALOFT WILL INCREASE AHEAD OF A WEAK NRN
STREAM DISTURBANCE. THE COMBINATION OF THE DISTURBANCE ACROSS THE
NRN PLAINS...INCREASING MOISTURE ALOFT AND STRONG SFC HEATING
SHOULD PRODUCE ISOLATED LATE AFTERNOON TSTMS. MODEL QPF IS
IGNORING THE VERY DRY AIR BELOW 700 MB AND PRODUCING QPF AS HIGH
AS .66 INCHES. THE NAM INDICATED DELTA T-TD HIGHER THAN 40 DEGREES
YET STILL PRODUCED 2/3 OF AN INCH OF QPF. SO POPS ARE LIMITED TO
THE ISOLATED CATEGORY. K INDICES IN THE MODEL ARE BELOW 40C WHICH
IS GENERALLY THE LIMIT FOR SCATTERED STORM COVERAGE. WE WILL SEE
IF THE MODELS CAN SHOW DEEPER MOISTURE BEFORE RAISING FCST POPS.
IN THE WAKE OF THE DISTURBANCE WEDNESDAY NIGHT...A WEAK COLD FRONT
WILL DROP THROUGH WRN NEB IN THE MORNING ANGLED SW THROUGH KIML AND INTO
A SFC HEAT LOW ACROSS ERN COLO. THE FRONT WILL DRIFT SOUTH AND
EAST THROUGHOUT THE AFTERNOON. SOUTHWEST WINDS BELOW 700 MB WILL HAVE
EVACUATED WHATEVER MOISTURE WAS THERE AND THE DEPARTING UPPER
LEVEL DISTURBANCE WILL DRY OUT THE ATM ALOFT. THUS NO RAIN IS EXPECTED
THURSDAY EXCEPT PERHAPS ACROSS CNTL NEB DEPENDING ON THE LOCATION
OF THE FRONT.
A DEEP UPPER LEVEL DISTURBANCE WILL BE TRACKING THROUGH SRN
ALBERTA AND SRN SASKATCHEWAN FRIDAY. THIS SYSTEM SHOULD DRAW DEEPER
MOISTURE FROM TEXAS NORTH THROUGH WRN NEB DURING THE AFTERNOON AND
SUFFICIENT UPPER LEVEL FORCING SHOULD BE AVAILABLE FOR ISOLATED
STORM DEVELOPMENT FRIDAY AFTERNOON. A BROAD AREA OF STRATUS MAY DEVELOP
FRIDAY MORNING AS MOISTURE LIFTS NORTH. ALL SOLNS EXCEPT THE NAM12
SHOW THIS FORMING.
TEMPERATURES ARE EXPECTED TO RISE INTO THE 90S WEDNESDAY THROUGH
FRIDAY. VERTICAL MIXING PROFILES MAY BE LIMITED AS THE SFC LOW
WILL GENERALLY DROP DUE SOUTH THROUGH THE HIGH PLAINS VS TRACKING
EAST THROUGH SRN SD. SO MAX TEMPS FOLLOW A MIDDLE OF THE ROAD
APPROACH FOR A MIX OF HIGHS IN THE LOWER...MIDDLE AND A FEW UPPER 90S.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
DECENT LOW AND MID LEVEL MOISTURE WILL SPREAD NORTH INTO THE AREA
FROM THE SOUTH FRIDAY NIGHT AHEAD OF A DECENT MID LEVEL DISTURBANCE.
850 MB DEW PTS PER THE ECMWF ARE PROGGED TO RISE TO NEAR 16C.
CHANCES FOR RAIN ARE EXPECTED TO INCREASE SATURDAY AS THE
DISTURBANCE MOVES ACROSS THE AREA...BUT RIGHT NOW MODELS INDICATING
THE BEST FOCUS FOR RAINFALL/CONVECTION MAY STAY SOUTH AND EAST OF
THE AREA. SO WON/T GET CARRIED AWAY WITH POPS...AND JUST CONTINUE
THE INHERITED 40 PERCENT CHANCES. SYSTEM MOVES EAST OF THE AREA
SUNDAY...WITH DRY WEATHER EXPECTED THE FIRST OF NEXT WEEK.
TEMPERATURE WISE...NEAR SEASONAL HIGHS IN THE 80S ARTE EXPECTED FOR
THE WEEKEND. BY EARLY NEXT WEEK HIGHS COULD REACH BACK INTO THE
LOWER 90S. LOWS WILL BE QUITE MILD WITH THE INCREASED
MOISTURE...WITH MOST AREAS STAYING IN THE 60S AT NIGHT.
FIRE WEATHER... BREEZY SOUTHERLY WINDS WILL INCREASE WEDNESDAY IN
RESPONSE TO A TIGHTENING PRESSURE GRADIENT ACROSS THE AREA. SOME
INCREASE IN LOW LEVEL MOISTURE IS EXPECTED...AND MINIMUM RELATIVE
HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 20 PERCENT. THE NAM
MODEL MAY BE DRYING OUT THE LOW LEVELS A LITTLE TOO MUCH ACROSS
CENTRAL NEBRASKA BASED ON WHAT IS OCCURRING TODAY...AND WILL FORGO
A FIRE WEATHER WATCH FOR THE THAT AREA AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
946 PM CDT THU AUG 23 2012
.DISCUSSION...
UPDATES WERE TO INCREASE SKY AND POPS. LATEST HRRR HAS A GOOD
HANDLE ON ONGOING CONVECTION AND LEANED IN ITS DIRECTION FOR POPS
REST OF TONIGHT.
LLJ RAMPING UP COMBINED WITH INCREASING MID LEVEL FORCING HAS LED
TO SCATTERED THUNDERSTORMS OVER EASTERN MONTANA ADVECTING EAST
INTO/TOWARDS WESTERN NORTH DAKOTA. THIS ACTIVITY SHOULD CONTINUE
EAST ACROSS THE FORECAST AREA SO INCREASED POPS AND SKY COVER.
&&
.AVIATION...
FOR THE 06Z TAF ISSUANCE...WILL ADD A TEMPO AND VCTS FOR KISN AND
KDIK.
PREVIOUS DISCUSSION...HIGH PRESSURE EXTENDED FROM FAR SOUTH
CENTRAL CANADA THROUGH THE CENTRAL DAKOTAS. TONIGHT A COLD FRONT
IS FORECAST TO APPROACH FAR WESTERN NORTH DAKOTA AROUND 06Z-
09Z...AND MOVE INTO THE CENTRAL DAKOTAS BY 18Z. WINDS WILL SHIFT
EAST/SOUTHEAST TONIGHT AHEAD OF THE APPROACHING COLD FRONT...THEN
TREND TOWARDS WEST/NORTHWEST FRIDAY BEHIND THE FRONT. WILL
MAINTAIN VCSH AT KMOT/KBIS FOR NOW WITH UNCERTAINTY PRETTY HIGH
FOR A THUNDERSTORMS TO TRACK OVER ANY ONE TERMINAL. WILL MONITOR
AND UTILIZE TEMPO GROUPS AS NEEDED. OVERALL VFR CONDITIONS SHOULD
PREVAIL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR NDZ001>003-009>011-017>021-031>034-040>045.
RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ TO 10 PM CDT /9 PM
MDT/ FRIDAY FOR NDZ001-009-017-031-032-040-043.
&&
$$
UPDATE/AVIATION...NH
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1007 PM CDT THU AUG 23 2012
.UPDATE...
A MINOR UPDATE HAS BEEN SENT TO ADJUST POPS A BIT THROUGH THIS
EVENING.
&&
.DISCUSSION...
TWO AREAS OF MOIST CONVECTION ARE PRESENT THIS EVENING OUTSIDE OF
OUR FA. THE FIRST...AND MORE ORGANIZED...IS LOCATED ACROSS NORTH
CENTRAL AND WEST CENTRAL KS. THE OTHER LOOSELY DEFINED AREA
EXTENDS FROM THE TX PANHANDLE SSWD THROUGH SE NM AND WEST
TX...AHEAD OF AN APPROACHING UPPER LOW CLEARLY SEEN PASSING OVER
THE FOUR CORNERS REGION. MOST OF THE MODELS GENERALLY HAVE SOME
CLUE WITH REGARDS TO THIS ACTIVITY...BUT PREVIOUS HRRR RUNS AND
ECMWF APPEAR TO HAVE THE BEST IDEA. THAT BEING SAID...A LLJ WILL
DEVELOP SIMILAR TO LAST NIGHT WEST OF I35. THE PREVIOUS MAY HELP
MAINTAIN/AMPLIFY THIS ACTIVITY AS IT APPROACHES BOTH FROM THE WEST
AND NORTH ESPECIALLY ACROSS WESTERN AND NORTHERN OKLAHOMA THROUGH
THE EARLY MORNING HOURS.
&&
.PREV DISCUSSION... /ISSUED 650 PM CDT THU AUG 23 2012/
AVIATION...
24/00Z TAFS...PRIMARILY VFR FORECAST WITH MVFR CONDITIONS IN/NEAR
THUNDERSTORMS. AREA OF RAIN WITH EMBEDDED THUNDERSTORMS PROGD BY
MOST MODELS TO MOVE INTO NORTHWEST PORTIONS OF OKLAHOMA TOWARD AND
AFTER MIDNIGHT THEN PROGRESS EASTWARD AND WEAKEN THROUGH TOMORROW
MORNING. LATEST HRRR AND RECENT RUNS OF OUNWRF SUPPORT THIS IDEA.
WILL KEEP TEMPO MENTIONED MAINLY AT NORTHERN AND FAR WESTERN
OKLAHOMA TERMINALS WHERE COVERAGE MAY BE A BIT HIGHER. WILL
INCLUDE /AMD NOT SKED/ AT KCSM WHERE FAA COMMS ISSUES CONTINUE.
PREV DISCUSSION... /ISSUED 336 PM CDT THU AUG 23 2012/
DISCUSSION...
SCATTERED LIGHT SHOWERS ASSOCIATED WITH MID-LEVEL
CLOUDS...CONTINUE TO DRIFT ACROSS OKLAHOMA AND THE TEXAS
PANHANDLE THIS AFTERNOON IN ADVANCE OF AN UPPER TROUGH.
THE UPPER TROUGH/LOW OVER SOUTHERN UTAH WILL NOT MOVE
ACROSS THE SOUTHERN PLAINS UNTIL SATURDAY/SUNDAY.
MEANWHILE...IT APPEARS BETTER CHANCES FOR SHOWERS/SOME STORMS
WILL BE ACROSS PARTS OF WESTERN AND NORTHERN OKLAHOMA NEAR A
STRONGER LOW LEVEL FLOW AND MID-LEVEL MOISTURE. IF A LARGE ENOUGH
AREA OF PRECIP CAN DEVELOP...BETTER CHANCES OF RAIN/STORMS MAY
MOVE INTO CENTRAL AND SOUTHERN OKLAHOMA TONIGHT INTO FRIDAY NIGHT.
MODELS AND HPC GUIDANCE CONTINUE TO SHOW THE POTENTIAL FOR 1 TO 3
INCH RAINFALL AMOUNTS THROUGH EARLY SUNDAY...MAINLY NORTHWEST OF
I-44.
AFTER SUNDAY/MONDAY...HEIGHT RISES ASSOCIATED WITH A
STRENGTHENING MID/UPPER LEVEL RIDGE WILL BRING DRY AND
HOTTER CONDITIONS TUESDAY INTO THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 91 69 86 72 / 20 20 40 60
HOBART OK 89 68 89 70 / 30 50 50 50
WICHITA FALLS TX 94 70 91 74 / 20 20 30 30
GAGE OK 89 68 90 69 / 30 60 50 60
PONCA CITY OK 92 69 85 71 / 20 40 50 60
DURANT OK 90 68 89 73 / 10 10 20 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
03/11
AREA FORECAST DISCUSSION
NWS NORMAN OK
650 PM CDT THU AUG 23 2012
.AVIATION...
24/00Z TAFS...PRIMARILY VFR FORECAST WITH MVFR CONDITIONS IN/NEAR
THUNDERSTORMS. AREA OF RAIN WITH EMBEDDED THUNDERSTORMS PROGD BY
MOST MODELS TO MOVE INTO NORTHWEST PORTIONS OF OKLAHOMA TOWARD AND
AFTER MIDNIGHT THEN PROGRESS EASTWARD AND WEAKEN THROUGH TOMORROW
MORNING. LATEST HRRR AND RECENT RUNS OF OUNWRF SUPPORT THIS IDEA.
WILL KEEP TEMPO MENTIONED MAINLY AT NORTHERN AND FAR WESTERN
OKLAHOMA TERMINALS WHERE COVERAGE MAY BE A BIT HIGHER. WILL
INCLUDE /AMD NOT SKED/ AT KCSM WHERE FAA COMMS ISSUES CONTINUE.
&&
.PREV DISCUSSION... /ISSUED 336 PM CDT THU AUG 23 2012/
DISCUSSION...
SCATTERED LIGHT SHOWERS ASSOCIATED WITH MID-LEVEL
CLOUDS...CONTINUE TO DRIFT ACROSS OKLAHOMA AND THE TEXAS
PANHANDLE THIS AFTERNOON IN ADVANCE OF AN UPPER TROUGH.
THE UPPER TROUGH/LOW OVER SOUTHERN UTAH WILL NOT MOVE
ACROSS THE SOUTHERN PLAINS UNTIL SATURDAY/SUNDAY.
MEANWHILE...IT APPEARS BETTER CHANCES FOR SHOWERS/SOME STORMS
WILL BE ACROSS PARTS OF WESTERN AND NORTHERN OKLAHOMA NEAR A
STRONGER LOW LEVEL FLOW AND MID-LEVEL MOISTURE. IF A LARGE ENOUGH
AREA OF PRECIP CAN DEVELOP...BETTER CHANCES OF RAIN/STORMS MAY
MOVE INTO CENTRAL AND SOUTHERN OKLAHOMA TONIGHT INTO FRIDAY NIGHT.
MODELS AND HPC GUIDANCE CONTINUE TO SHOW THE POTENTIAL FOR 1 TO 3
INCH RAINFALL AMOUNTS THROUGH EARLY SUNDAY...MAINLY NORTHWEST OF
I-44.
AFTER SUNDAY/MONDAY...HEIGHT RISES ASSOCIATED WITH A
STRENGTHENING MID/UPPER LEVEL RIDGE WILL BRING DRY AND
HOTTER CONDITIONS TUESDAY INTO THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 69 86 72 86 / 30 40 60 60
HOBART OK 68 89 70 88 / 40 50 50 30
WICHITA FALLS TX 70 91 74 91 / 20 30 30 30
GAGE OK 68 90 69 86 / 60 50 60 50
PONCA CITY OK 69 85 71 86 / 50 50 60 70
DURANT OK 68 89 73 89 / 10 20 40 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
03/11/11
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
929 PM CDT THU AUG 23 2012
.UPDATE...
LARGE BUT LOOSELY ORGANIZED LINE OF SHOWERS AND STORMS WAS FOUND
STRETCHING FROM DALHART SOUTH TO THE UPPER RIO GRANDE LATE THIS
EVENING IN ADVANCE OF AN UPPER TROUGH CURRENTLY IN CENTRAL NEW
MEXICO. RECENT IR SATELLITE IMAGERY CONFIRMS A DECAYING PROCESS
UNDERWAY WITH THE CONVECTION OVER THE MIDDLE EXTENT OF THE LINE
/ROUGHLY NEAR CLOVIS/ WITH RENEWED DEVELOPMENT FARTHER SOUTH FROM
EASTERN LEA COUNTY INTO THE FAR SOUTHWEST SOUTH PLAINS ATTENDANT
WITH AN APPARENT MCV PER REGIONAL 88D DATA. ALTHOUGH MINIMAL CAPE
WILL GOVERN THE REMAINDER OF THE OVERNIGHT...STEADY LIFT AND
SLIGHTLY DEEPER MOISTURE IN ADVANCE OF THIS CONVECTION SHOULD
SUSTAIN ISOLATED TO SCATTERED STORMS OVER THE REMAINDER OF THE
SOUTH PLAINS AS THIS ACTIVITY CONTINUES STEADILY EAST. BUMPED POPS
UP ACCORDINGLY THROUGH 06Z WITH REDUCED VALUES THEREAFTER AS
CONVECTION SLOWLY WANES AND OUTRUNS THE UPPER SUPPORT. RECENT RUNS
OF THE HRRR ARE PERFORMING REASONABLY WELL IN DEPICTING THE
AFOREMENTIONED DECAYING TREND NEAR CLOVIS WITH PREFERRED
DEVELOPMENT FARTHER SOUTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 88 64 90 64 / 60 20 20 20 20
TULIA 66 87 66 90 65 / 50 20 30 20 30
PLAINVIEW 67 86 66 90 66 / 50 20 30 20 30
LEVELLAND 66 86 67 93 67 / 60 20 20 20 20
LUBBOCK 69 89 68 93 68 / 50 20 20 20 20
DENVER CITY 64 87 68 94 67 / 60 20 20 20 20
BROWNFIELD 64 87 67 94 68 / 60 20 20 20 20
CHILDRESS 70 88 70 94 70 / 30 30 30 20 30
SPUR 68 89 69 93 70 / 30 30 30 20 20
ASPERMONT 71 90 72 96 72 / 30 30 30 20 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS AMARILLO TX
321 PM CDT WED AUG 22 2012
.DISCUSSION...
ALREADY SEEING A TRANSITION FROM NORTHWESTERLY FLOW ALOFT TO MORE
WESTERLY FLOW ALOFT IN RESPONSE TO THE APPROACHING CUTOFF LOW
CURRENTLY IN SOUTHERLY CA.
FOR TONIGHT...STORMS FROM THE HIGHER TERRAIN OF NM AND CO WILL
QUICKLY MOVE INTO THE NORTHWESTERN PANHANDLES. THE RAP IS SHOWING
THIS AREA WITH SLIGHTLY HIGHER CAPE VALUES...NEAR 2000 J/KG...AND
MODEST SHEAR VALUES NEAR 30 KT. HOWEVER...THE SEVERE THREAT SHOULD
NOT LAST LONG AS MODEL SOUNDINGS SHOW ONLY ELEVATED INSTABILITY BY
03Z.
TOMORROW AND TOMORROW NIGHT...WILL PROBABLY BE THE BEST CHANCE FOR A
WIDESPREAD RAIN EVENT...ESPECIALLY TOMORROW NIGHT...WITH VORTICITY
ADVECTION AHEAD OF THE MAIN UPPER LEVEL TROUGH. THE BIGGER CONCERN
HOWEVER WILL BE THE POTENTIAL FOR HEAVY RAIN LEADING TO LOCALIZED
FLASH FLOODING...AS PRECIPITABLE WATER VALUES COULD BE ABOVE 1.5
INCHES AND MEAN STORM MOTIONS COULD BE BELOW 20 KT.
FRIDAY THROUGH SUNDAY...SOME CHANCES FOR THUNDERSTORMS CONTINUE
THROUGH THIS PERIOD. HOWEVER...THERE IS UNCERTAINTY IN THE TRACK OF
THE CENTER OF THE UPPER LEVEL LOW. IF THE LOW GOES JUST SOUTH OF THE
TX PANHANDLE AS THE GFS SHOWS...THERE SHOULD BE A RELATIVELY GOOD
CHANCE FOR RAIN THROUGH THE WEEKEND. HOWEVER...ANY DEVIATION TO THE
NORTH...LIKE THE ECMWF SHOWING THE LOW LIFTING NE ACROSS THE TX
PANHANDLE ON SAT...COULD MEAN THE REGION WOULD BE IN THE PRIME
LOCATION FOR THE DRY SLOT...AND THUS HAVE FEW IF ANY CHANCES FOR
STORMS. LIKELY THIS UNCERTAINTY WILL REMAIN FOR THE NEXT FEW MODEL
RUNS AS THE PATH OF THIS LOW IS SOMEWHAT DEPENDENT ON THE EVOLUTION
OF A SECOND UPPER LEVEL TROUGH THAT SHOULD MOVE ACROSS THE NORTHERN
TIER OF THE U.S. AT THE SAME TIME...BUT HAS NOT YET BEEN WELL SAMPLED
BY THE UPPER AIR NETWORK.
MONDAY THROUGH WEDNESDAY...A RIDGE IS EXPECTED TO BUILD OVER THE HIGH
PLAINS...MINIMIZING THE CHANCE FOR RAIN AND BRINGING A WARMING TREND
AT LEAST TO START THE WEEK.
JOHNSON
&&
.FIRE WEATHER...
RELATIVELY HIGH ATMOSPHERIC MOISTURE...AND CONTINUED RAIN CHANCES
SHOULD PRECLUDE ANY ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS FOR
THE NEXT SEVERAL DAYS.
JOHNSON
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 64 84 65 89 65 / 20 30 40 30 30
BEAVER OK 67 89 67 92 68 / 20 30 40 40 40
BOISE CITY OK 64 91 64 89 63 / 30 30 40 30 30
BORGER TX 67 87 68 91 69 / 20 30 40 30 30
BOYS RANCH TX 66 89 66 92 65 / 30 30 40 30 30
CANYON TX 64 85 64 89 64 / 20 30 40 30 20
CLARENDON TX 65 89 68 90 67 / 20 30 40 30 30
DALHART TX 64 91 63 90 61 / 30 30 40 30 30
GUYMON OK 65 89 66 91 66 / 30 30 40 30 40
HEREFORD TX 64 86 63 89 62 / 20 30 40 20 20
LIPSCOMB TX 67 87 69 89 69 / 20 30 40 40 40
PAMPA TX 64 87 66 87 65 / 20 30 40 30 30
SHAMROCK TX 66 86 68 87 68 / 20 30 40 40 40
WELLINGTON TX 66 90 68 89 70 / 20 30 40 30 30
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/16
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
314 PM CDT WED AUG 22 2012
.SHORT TERM...
EARLIER SHOWERS AND STORMS ACROSS THE BIG COUNTRY HAVE NOW
DISSIPATED FOR THE MOMENT. HOWEVER...CU FIELD HAS STARTED TO DEVELOP
ONCE AGAIN...AND THE VARIOUS WRF MODELS AND THE HRRR ALL SHOW SOME
VARYING DEGREE OF CONVECTION POPPING UP ACROSS WEST CENTRAL TEXAS
FOR A FEW HOURS LATE THIS AFTERNOON AND INTO THE EVENING. WILL
INCLUDE A MENTION OF ISOLATED STORMS FOR THE FIRST PERIOD.
OTHERWISE...FAIRLY QUIET PATTERN FOR THE NEXT 36 HOURS. LEE TROUGH
BECOMES BETTER ESTABLISHED ACROSS THE EASTERN NEW MEXICO AND WEST
TEXAS...WITH SOUTHERLY WINDS INCREASING AHEAD OF IT. MORE HIGH
CLOUDS ON THURSDAY......BUT NOT ENOUGH TO HAVE A REALLY SIGNIFICANT
EFFECT ON TEMPERATURES.
07
.LONG TERM...
A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IS FORECAST FOR PARTS
OF THE AREA DURING THE FIRST PART OF THE EXTENDED FORECAST. AN UPPER
LEVEL HIGH WILL BEGIN TO SHIFT SOUTH INTO MEXICO THURSDAY...WHILE AN
UPPER LEVEL TROUGH APPROACHES FROM THE WEST. AT THE SAME TIME A LEE
TROUGH WILL DEVELOP OVER THE TEXAS PANHANDLE...RESULTING IN
INCREASING SOUTH TO SOUTHEAST WINDS. SHOWERS AND THUNDERSTORMS MAY
DEVELOP OVER PARTS OF WEST TEXAS BY LATE AFTERNOON/EARLY EVENING
THURSDAY...WHERE BETTER SURFACE CONVERGENCE IS EXPECTED. A FEW OF
THESE STORMS MAY DRIFT INTO PARTS OF OUR WESTERN COUNTIES...SO HAVE
INCLUDED SLIGHT CHANCE POPS AFTER 00Z FRIDAY.
MODELS ARE HINTING AT A COUPLE OF SHORTWAVE TROUGHS MOVING ACROSS
NORTH TEXAS. THE FIRST IS WEAKER AND IS FORECAST TO TREK ACROSS THE
PANHANDLE EARLY FRIDAY MORNING. AT THIS TIME...BELIEVE THE MAJORITY
OF PRECIPITATION WILL REMAIN NORTH OF OUR AREA...BUT KEPT SLIGHT
CHANCE POPS OVER THE NORTHERN BIG COUNTRY. THE NEXT...MORE
POTENT...UPPER LEVEL SHORTWAVE TROUGH WILL APPROACH FRIDAY THEN MOVE
ACROSS NORTH TEXAS AND OKLAHOMA SATURDAY. ONCE AGAIN...ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...WITH THE
FAVORED AREAS BEING OUR NORTHERN AND WESTERN COUNTIES. I KEPT SLIGHT
CHANCE POPS IN FOR FRIDAY AND INTRODUCED SLIGHT CHANCE POPS ON
SATURDAY FOR THE WESTERN HALF OF THE REGION. BEYOND
SATURDAY...MODELS ARE HINTING AT A WEAK COLD FRONT MOVING INTO THE
TEXAS PANHANDLE SUNDAY...WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING JUST NORTH OF OUR AREA. FOR NOW...I HAVE LEFT THE
FORECAST DRY BEYOND SATURDAY...BUT FUTURE SHIFTS MAY NEED TO
INTRODUCE POPS. HIGH TEMPERATURES THROUGH THE EXTENDED WILL BE NEAR
TO SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD...GENERALLY IN THE MID
90S.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 69 94 73 93 74 / 10 10 10 20 20
SAN ANGELO 68 95 73 95 75 / 10 10 10 20 20
JUNCTION 67 93 72 94 74 / 20 10 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/DANIELS
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
655 AM CDT WED AUG 22 2012
.DISCUSSION...
12Z TAF BULLETIN RATIONAL BELOW.
&&
.AVIATION...
UPPER TROUGH LOCATED JUST OVER NW GULF OF MEXICO THIS MORNING WITH
DRY SUBSIDENT AIR SEEN BEHIND IT OVER MUCH OF SE TX ON WV IMAGERY.
IR SATELLITE LOOPS AND METARS SHOW MID LAYER CIG FL080-100 ACROSS
MOST OF THE TAF SITES THIS MORNING. DIFFUSE STATIONARY FRONT
DRAPED ACROSS SE TX ALONG WITH OUTFLOW BOUNDARIES GALORE FROM
OFFSHORE AND NEARSHORE CONVECTION THIS MORNING. LOOKS FAIRLY QUIET
AT KGLS AND KLBX THE NEXT COUPLE OF HOURS WITH VCSH/VCTS GRADUALLY
MAKING ITS WAY INLAND WITH SEA BREEZE/OUTFLOW BOUNDARIES. UPPER
DRYING SHOULD GRADUALLY ERODE MIDLEVEL CIGS BY LATE MORNING PER
FCST SOUNDINGS. HGX WRF-ARW AND HRRR REFLECTIVITY FORECASTS AGREE
WITH SCATTERED CONVECTION FORMING ALONG THESE BOUNDARIES TODAY AND
HAVE SO FAR PERFORMED DECENTLY THIS MORNING. LOOKS LIKE THIS
ACTIVITY MAY SPREAD AS FAR NORTH AS THE SOUTH PART OF THE TAF
VCNTY DONUT FOR KCXO BY MID-AFTN. WITH LOSS OF HEATING ACTIVITY
SHOULD DIMINISH BY LATE AFTERNOON/EARLY EVENING. GIVEN THE
COMPETING FACTORS FOR AND AGAINST CONVECTION WOULD EXPECT SCT
COVERAGE. SOME INDICATION IN FORECAST SOUNDINGS AND NAM/GFS MOS
GUIDANCE FOR SOME MVFR FOG AT RURAL KCXO AND KLBX SITES TOWARDS
SUNRISE. ADDITIONAL OFFSHORE SHRA/TS IS FORECAST TOMORROW MORNING
SO HAVE INCLUDED VCSH AT KGLS. 04
&&
.PREV DISCUSSION... /ISSUED 459 AM CDT WED AUG 22 2012/
DISCUSSION...
NORTHWESTERLY FLOW ALOFT WILL CONTINUE TO AFFECT SE TX THROUGH THE
END OF THE WEEK...WITH A WEAKNESS IN THE RIDGE JUST EAST OF THE
STATE. A WEAK SURFACE BOUNDARY WAS PRESENT ACROSS GALVESTON BAY
EASTWARD INTO THE GULF EARLY THIS MORNING...WITH DEEP LAYER
MOISTURE PRESENT JUST TO THE SOUTH. THE SURFACE FEATURE WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS THIS MORNING. LATER
TODAY...A SHORTWAVE TROUGH MOVING THROUGH THE FLOW ALOFT WILL HELP
GENERATE MORE CONVECTIVE ACTIVITY AT LEAST OVER THE SOUTHERN HALF
OF THE FORECAST AREA AS THE MOISTURE STREAMS NORTHWARD OVER THE
SURFACE BOUNDARY AND ANY SEABREEZE THAT DEVELOPS. THE SAME GENERAL
SCENARIO LOOKS TO OCCUR ON THURSDAY...AND THEN AGAIN ON FRIDAY.
THE CLOUD COVER EACH DAY WILL GENERALLY KEEP THE AFTERNOON
TEMPERATURES IN THE LOWER 90S AT MOST INLAND SITES AWAY FROM THE
COAST.
THE MODELS BEGIN TO DIFFER OVER THE WEEKEND...WITH THE GFS AND
ECMWF PATTERNS NOT IN VERY GOOD AGREEMENT DURING THE FIRST HALF OF
NEXT WEEK. GIVEN THE LARGE UNCERTAINTY AND LOW CONFIDENCE IN BOTH
MODELS...FELT THAT THE BEST SOLUTION WAS TO STAY WITH ISOLATED
CHANCES MAINLY DURING THE DAYTIME DUE TO SEABREEZE ACTIVITY.
40
MARINE...
COUPLE OF BOUNDARIES EVIDENT ON RADAR LOOPS...ONE STRETCHING FROM
ANGLETON TO ABOUT 15 MILES OFFSHORE OF THE BOLIVAR PENINSULA AT
09Z THIS MORNING. MOSTLY SHOWERS BUT OCCASIONALLY SOME CG LTG
BEING DETECTED. BOUNDARY IS DRIFTING SLOWLY INLAND WITH MEAN LOW
LEVEL FLOW. SECOND BOUNDARY JUST BEGINNING TO SHOW UP AROUND 20-25
NMI OFFSHORE ROUGHLY PARALLEL TO COAST. THESE BOUNDARIES SHOULD
COMBINE WITH UPPER TROUGH/DIFFLUENCE TO PRODUCE A GOOD CHANCE FOR
SHOWERS AND STORMS FOR NEARSHORE/BAY/OFFSHORE WATERS TODAY
ESPECIALLY THIS MORNING. SIG WAVE HGTS SHOULD REMAIN IN THE 1 TO 3
FOOT RANGE THE NEXT SEVERAL DAYS WITH ONSHORE FLOW. SOME
DIURNAL/LATE NIGHT INCREASE IN WIND SPEEDS POSSIBLE THU NGT/FRI
MORNING MAY INCREASE SOME WAVE HGT TO AROUND 4 FT.
04
AVIATION...
SHORT TERM UPDATES FOR OBSERVED SHRA/TSRA TRENDS WITH BOUNDARY
NEAR COASTAL TAF SITES...KGLS AND KLBX THIS MORNING. EARLY
INDICATIONS FOR PCPN CHANCES SUGGEST LEAVING OUT OF TAFS NORTH OF
THE METRO AREA. WILL EVALUATE NEED FOR VCSH/VCTS GROUPS FOR KIAH
AND KHOU FOR THE 12Z TAF PACKAGE.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 92 72 92 74 91 / 10 10 10 10 20
HOUSTON (IAH) 90 73 92 75 90 / 30 10 30 20 40
GALVESTON (GLS) 89 80 91 81 90 / 30 20 40 20 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...04
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
901 PM CDT THU AUG 23 2012
.UPDATE...
THE NAM/GFS AND RUC TRY TO GENERATE SOME LIGHT QPF ACROSS THE
EASTERN HALF OF THE CWA OVERNIGHT...WITHIN THE CONVERGENCE REGION OF
A STRENGTHENING LOW LEVEL JET CENTERED DOWN AROUND 900-925MB.
THE LAPSE RATES ABOVE THIS ARE FAIRLY STEEP AND COULD ALLOW FOR
SOME WEAK UPDRAFTS TO PRODUCE SOME SHOWERS OR SPRINKLES. GIVEN THE
BASES...I/D SAY IT/S MAINLY SPRINKLES. HOWEVER...THE CANADIAN
MODELS/ECMWF AND THE HIRES ARW/NMM CORE MODELS DON/T HAVE ANY QPF.
FOR NOW WILL KEEP PRECIP MENTION OUT AS SATELLITE IMAGERY NOT
SHOWING ANY ACCAS TYPE CLOUDS DEVELOPING. IN FACT...CLOUDS ARE
DISSIPATING ATTM. FOR LATER...THERE IS A MID LEVEL SHORT WAVE THAT
WILL CLIP ACROSS CENTRAL AND NORTHERN WISCONSIN TONIGHT. THE
PREVIOUS FCST LIMITED ANY PRECIP IN OUR FCST AREA TO THE NORTHERN
TIER OF COUNTIES AND THIS STILL LOOKS OKAY. MOST OF THE FORCING
AND CONCERN SHOULD BE NORTH OF OUR AREA. WE ARE IN THE WARM SECTOR
UNTIL FURTHER NOTICE.
&&
.AVIATION/06Z TAFS/...
VFR CONDITIONS THROUGH THE PERIOD. DECIDED TO PUT IN LOW LEVEL
WIND SHEAR WITH THE STRENGTHENING LOW LEVEL JET SEGMENT STRETCHING
FROM SHEBOYGAN/FOND DU LAC COUNTIES SOUTH SOUTHWEST TO
ROCK/WALWORTH/RACINE/KENOSHA COUNTIES LATER THIS EVENING AND
OVERNIGHT. WINDS SHOULD REMAIN DECOUPLED...BUT THE INVERSION
LOOKS SHARP AT 1000FT AND WINDS CRANK TO 30KTS OR BETTER VERY
RAPIDLY WITH HEIGHT.
WILL ALSO BE KEEPING A LOOKOUT FOR ELEVATED SHOWERS DEVELOPING
WITHIN THIS REGION...BUT NOTHING SIGNIFICANT IF THEY DO OCCUR.
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT THU AUG 23 2012/
SHORT TERM...
TONIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM.
A SHORTWAVE TROUGH OVER MN WILL SWING ACROSS WI TONIGHT. THE
STRONGEST FORCING WILL REMAIN WELL TO OUR NORTHWEST. HOWEVER...THERE
COULD BE A SMALL CHANCE FOR SHOWERS OR A THUNDERSTORM TO BRUSH THE
NORTHWEST FORECAST AREA AS THE SHORTWAVE AND THE 850MB LOW LEVEL JET
AXIS APPROACHES...SO KEPT SLIGHT CHANCE THERE.
CONTINUED THAT SLIGHT CHANCE ACROSS FAR NORTHERN FORECAST AREA
INCLUDING FOND DU LAC THROUGH FRIDAY AFTERNOON UNTIL THE WAVE CLEARS
THE AREA. THE CHANCE FOR PRECIP WILL BE VERY SMALL SINCE LOW LEVELS
WILL REMAIN DRY AND THERE WILL BE ONLY A LITTLE ELEVATED
INSTABILITY.
CLOUDS AND STIRRING WITH SURFACE WINDS OF 5 TO 6 KNOTS WILL HOLD
LOWS IN THE MID TO UPPER 60S TONIGHT. TEMPERATURES WILL BE SLIGHTLY
WARMER ON FRIDAY THAN THEY WERE TODAY WITH DEEPER MIXING...MOST
LIKELY LESS CLOUD COVER...AND 925MB TEMPS ABOUT A DEGREE WARMER AT
27C. HIGHS IN THE LOWER 90S INLAND. DECENT SOUTHWEST BREEZE DURING
THE AFTERNOON WITH THE DEEP MIXING...SO GUSTS TO 20 MPH ALSO
POSSIBLE. A LAKE BREEZE IS EXPECTED ONCE AGAIN.
FRIDAY NIGHT AND SATURDAY....FORECAST CONFIDENCE...MEDIUM
MAIN SHORTWAVE IS NEAR AND NORTH OF LAKE WINNIPEG WITH THE MAIN
95 KNOT 250 MB JET WELL NORTH ACROSS SOUTHERN MANITOBA AND WESTERN
ONTARIO. BEST UPPER DIVERGENCE IS WELL NORTH AND WEST FRIDAY NIGHT
WITH SOME WEAKENING DIVERGENCE MOVING ACROSS SOUTHERN WISCONSIN
SATURDAY AFTERNOON. ONLY WEAK UPWARD MOTION AT 700 MB AND THIS IS
SATURDAY AFTERNOON AS A 35 KNOT 700 MB WIND MAX EXTENDS ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY TOWARDS WESTERN LAKE SUPERIOR.
TROUGH OF LOW PRESSURE AND SURFACE COLD FRONT EXPECTED TO APPROACH THE
MISSISSIPPI RIVER ON SATURDAY.
LOOKS DRY THROUGH THE DAY AS THE HIGHEST 850 MB RH IS WITH AND
BEHIND THE FRONT...AND WITH NAM DEWPOINTS MIXING OUT ACROSS MUCH
OF THE FORECAST AREA.
SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE...MEDIUM
MAIN SHORTWAVES PUSHES NORTHEAST INTO NORTHEAST MANITOBA WITH WEAK
UPPER DIVERGENCE SATURDAY NIGHT THAT WEAKENS FURTHER ON SUNDAY.
700 MB WIND MAX PUSHES OFF TO THE NORTH. SOME WEAK 700 MB UPWARD
MOTION...BUT NOT REAL ORGANIZED. 30 KNOT 850 MB WIND MAX ACROSS
THE FORECAST AREA SATURDAY NIGHT BEFORE LIFTING NORTHEAST ON
SUNDAY. THE COLD FRONT MOVES ACROSS THE FORECAST AREA MAINLY
SUNDAY...BUT WEAKENS. ZERO TO 1 KM CAPE IS RATHER LOW AT AROUND
400 J/KG ON SUNDAY. NAM DOES PUT OUT AROUND 0.10 TO 0.33 WITH
FROPA.
LONG TERM...
MONDAY TROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
THE UPPER TROUGH PUSHES EAST INTO EASTERN CANADA AND DIGS A LITTLE
ACROSS THE NORTHEAST U.S. WISCONSIN IS IN A NORTHWEST FLOW WITH
AN UPPER RIDGE ACROSS THE NORTHERN ROCKIES ON THE 12Z GFS AND
NORTHERN PLAINS ON THE 00Z ECMWF MONDAY. THE 00Z ECMWF IS A LITTLE
FASTER ON TAKING THE UPPER RIDGE INTO THE NORTHERN MISSISSIPPI
VALLEY ON TUESDAY AND WEDNESDAY...WHILE THE 12Z GFS KEEPS IT WEST
ONLY REACHING THE NORTHERN PLAINS ON WEDNESDAY.
CHANCES OF PRECIPITATION WILL BE LOW.
THURSDAY...FORECAST CONFIDENCE...LOW TO MEDIUM
THE MID/UPPER TROUGHS ACROSS CANADA BECOME OUT OF PHASE BETWEEN
THE MODELS WITH THE 06Z DGEX EVEN FARTHER FROM THE ECMWF AND GFS.
HOWEVER THE GFS AND ECMWF HAVE A RATHER ZONAL FLOW ACROSS THE
U.S./CANADIAN BORDER.
THE ECMWF BRINGS A COLD FRONT AND PRECIP WEDNESDAY NIGHT AND
THURSDAY...WHILE THE GFS IS MUCH SLOWER WITH THIS...BUT DOES HAVE
SOME WARM AIR ADVECTION PRECIP.
AVIATION/00Z TAFS/...
VFR CONDITIONS WITH OCCASIONAL MID AND HIGH CLOUDS WILL CONTINUE
TONIGHT AND FRIDAY. WHILE THERE COULD BE A FEW SPRINKLES...NO
CONVECTION AT TAF SITES THROUGH FRIDAY NIGHT.
WINDS WILL DIE DOWN WITH SUNSET THIS EVENING. LOW LEVEL WIND SHEAR
POSSIBLE AROUND 2000 FEET WITH A 30 KNOT LOW LEVEL JET
OVERHEAD...BUT NOT ENOUGH DIRECTIONAL WIND SHEAR TO MENTION IN TAFS.
DEEP MIXING AGAIN ON FRIDAY WILL BRING STEADY SOUTHWEST WINDS WITH
GUSTS IN THE 20 KNOT RANGE DURING THE AFTERNOON...WITH A LAKE BREEZE
DEVELOPING ONCE AGAIN AT MKE AND ENW.
MARINE...
LOW PRESSURE APPROACHING FROM THE NORTHERN PLAINS AND HIGH PRESSURE
OVER THE EAST COAST WILL CAUSE AN INCREASING PRESSURE GRADIENT OVER
LAKE MICHIGAN. THE PRESSURE GRADIENT WILL REMAIN TIGHT THROUGH
SUNDAY AFTERNOON WHEN A COLD FRONT MOVES ACROSS THE REGION.
SOUTH TO SOUTHEAST WINDS 10 TO 20 KNOTS WITH A FEW GUSTS TO 25 KNOTS
POSSIBLE ON FRIDAY WILL CAUSE WAVES TO BUILD TO AROUND 4 FEET TOWARD
SHEBOYGAN BY FRI AFTERNOON...APPROACHING SMALL CRAFT ADVISORY
CONDITIONS. DO NOT EXPECT A HEADLINE AT THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/FRIDAY AND AVIATION/MARINE...MRC
FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
723 PM CDT THU AUG 23 2012
.SHORT TERM...TONIGHT
723 PM CDT THU AUG 23 2012
MAIN FORECAST CONCERN IS IF CONVECTION WILL MOVE INTO AND/OR
DEVELOP OVER THE FORECAST AREA TONIGHT.
00Z WATER VAPOR LOOP SHOWED A SHORTWAVE TROUGH ACROSS WESTERN
MINNESOTA. WEAK DPVA FORCING AHEAD OF THIS SHORTWAVE COMBINED WITH
WARM ADVECTION...AND MORE IMPORTANTLY INSTABILITY...HAS LED TO
SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT FROM SOUTHWEST INTO
CENTRAL MINNESOTA. MUCH OF THIS ACTIVITY WAS ALSO ON A WARM FRONT.
23Z RAP ANALYSIS DEPICTED MLCAPE VALUES AROUND 1500 J/KG WITH
MLCIN LESS THAN 50 J/KG WHERE THESE STORMS HAVE OCCURRED.
MODELS ARE IN GOOD AGREEMENT LIFTING THE SHORTWAVE TROUGH OVER
WESTERN MINNESOTA TO THE NORTHEAST TONIGHT...STRETCHING FROM
WESTERN LAKE SUPERIOR INTO NORTHERN WISCONSIN BY 12Z FRIDAY. BIG
QUESTION MARK IS HOW MUCH PRECIPITATION OCCURS WITH THIS TROUGH.
CONVECTION THUS FAR AT LEAST OVER SOUTHWEST MINNESOTA REALLY
SEEMS TIED TO DIURNAL INSTABILITY. OVER THE NEXT FEW HOURS...THE
MLCIN INCREASES GREATLY...OVER 100 J/KG BY 02Z PER THE RAP MODEL.
THEREFORE...THINK THOSE IN SOUTHWEST MINNESOTA WILL DISSIPATE
BEFORE THEY HAVE MUCH OF A CHANCE TO HEAD EAST OR NORTHEAST WITH
THE SHORTWAVE TROUGH. THOSE STORMS MORE OVER CENTRAL MINNESOTA ARE
MORE ON THE NOSE OF 850MB MOISTURE TRANSPORT...WHICH SHIFTS
NORTHEAST WITH THE SHORTWAVE TROUGH. SO ALTHOUGH MODELS SUCH AS
THE 23.18Z NAM/GFS AND 23.12Z ECMWF BRING CONVECTION INTO
NORTHWEST PORTIONS OF THE AREA...DEFINITELY HAVE DOUBTS. IN
FACT...THE 23.12Z HIRESW-ARW MODEL SUGGESTS THAT MUCH OF THE
CURRENT CONVECTION DISSIPATES BY 06Z...LEAVING THE OVERNIGHT DRY.
23.21Z HRRR ALSO HAS TRENDED DRIER...WITH THE EXCEPTION OF SOME
SCATTERED ELEVATED CONVECTION IT DEVELOPS ALONG/NORTH OF I-94
AFTER 10Z. FOR NOW...HAVE DELAYED ARRIVAL OF ANY PRECIPITATION
CHANCES TO AT LEAST 03Z...AND AFTER 03Z MOSTLY LOWERED
PRECIPITATION CHANCES EXCEPT FOR THE TAYLOR/CLARK AREA. THE REASON
FOR NOT ADJUSTING CHANCES IN TAYLOR/CLARK IS INDICATIONS OF
INCREASING 310K ISENTROPIC LIFT...REFLECTED IN BOTH THE 23.18Z NAM
AND 23.21Z HRRR.
IN SUMMARY...CONCERNED THAT NOT MUCH MAY HAPPEN FOR THE FORECAST
AREA TONIGHT. WILL WATCH CONVECTIVE TRENDS OVER THE NEXT FEW HOURS
AND ADJUST PRECIPITATION CHANCES AS NECESSARY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
240 PM CDT THU AUG 23 2012
23.12Z GFS/EC SHOW SUNDAY NIGHT THROUGH TUESDAY NIGHT LOOKING DRY AND
WARM AS A MID-LEVEL RIDGE OF HIGH PRESSURE BUILDS INTO THE CENTRAL
CONUS. LOOK FOR HIGHS MONDAY AND TUESDAY IN THE UPPER 70S TO MIDDLE
80S. BY WEDNESDAY INTO THURSDAY...WILL BE WATCHING LOW PRESSURE PUSH
ACROSS THE NORTHERN PLAINS TOWARD THE AREA. THIS SETS UP WAA
SCENARIO ACROSS THE AREA WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS WEDNESDAY/WEDNESDAY NIGHT. OTHERWISE...LOOKS LIKE
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THURSDAY WITH HIGHS
TOPPING OFF IN THE 80S.
&&
.AVIATION...TONIGHT AND FRIDAY
637 PM CDT THU AUG 23 2012
FORECAST CONCERNS THIS TAF PERIOD ARE PRECIPITATION CHANCES DURING
THE OVERNIGHT/EARLY FRIDAY MORNING HOURS AT KRST/KLSE. AS OF
00Z...UPPER LEVEL WAVE TRANSVERSING THE UPPER MIDWEST COMBINED
WITH INCREASING 850 MB MOISTURE TRANSPORT AND LIFT ARE ACTING AS
THE FOCUSING MECHANISM FOR SHOWERS/STORMS ACROSS CENTRAL MINNESOTA
TONIGHT. MOST OF THE ACTIVITY SHOULD REMAIN WEST/NORTH OF THE TAF
SITES...WHERE THE BETTER FORCING TRACKS. HOWEVER...THERE COULD BE
STRAY/LINGERING SHOWERS AS THIS PROGRESSES TOWARDS SOUTHEAST
MINNESOTA/WESTERN WISCONSIN OVERNIGHT. AS SUCH...MAINTAINED VCSH
MENTION STARTING AFTER 07Z AT KRST AND 09Z AT KLSE. IF
PRECIPITATION DOES MATERIALIZE...THERE COULD BE A BRIEF PERIOD OF
MVFR STRATUS/FOG AROUND SUNRISE WITH MOISTURE TRAPPED IN THE
BOUNDARY LAYER. ONCE DAYTIME HEATING ENSUES...THE LOW LEVELS WILL
QUICKLY MIX OUT.
VFR CONDITIONS EXPECTED FRIDAY WITH ANOTHER DAY OF DEEP MIXING...AND
BY LATE MORNING A SCATTERED TO BROKEN CUMULUS FIELD WITH BASES 5-7
KFT SHOULD DEVELOP. HAVE ADDED PERIOD OF AFTERNOON GUSTS AT KRST FOR
WINDS UP TO 20 KTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
240 PM CDT THU AUG 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....DAS
AVIATION...ZT
AREA FORECAST DISCUSSION...CORRECTED
NWS GREEN BAY WI
245 PM CDT WED AUG 22 2012
.SHORT TERM...TONIGHT AND THURSDAY.
MAIN CONCERN FOR THIS PERIOD WILL BE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND WEDNESDAY...THEN HIGH TEMPERATURES
WEDNESDAY AFTERNOON.
A CLUSTER OF SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHERN
MINNESOTA THIS MORNING AND WAS NOW NEAR THE MINNEAPOLIS AREA. THE
SHOWERS AND STORMS DEVELOPED DUE TO WEAK LOW LEVEL JET...850/700MB
WARM ADVECTION AND STEEP MID LEVEL LAPSE RATES. THESE STORMS PRODUCED
HALF OF A HALF INCH TO HALF DOLLAR SIZE HAIL THIS AFTERNOON. MOST OF
THE BASES OF THESE STORMS WERE AROUND 10 THOUSAND FEET. MODELS DID
NOT HAVE A GOOD HANDLE ON THE DEVELOPMENT OF THIS CLUSTER OF STORMS
AND ALSO DIFFER ON THE EVOLUTION OF THIS CLUSTER OF STORMS AS IT
MOVES EAST INTO WISCONSIN.
THE WRF INDICATES THE 850/700MB WARM ADVECTION WILL MOVE ACROSS
THE AREA TONIGHT WITH THE GREATEST WARM ADVECTION NORTH AND WEST OF
GREEN BAY AND THE FOX VALLEY. DO NOT SEE WHY CONVECTION WOULD END
THIS AFTERNOON AND THIS IS SUPPORTED BY THE LATEST RUC MODEL.
LOOKING AT SOME OF THE MESOSCALE MODELS LIKE THE SPC WRF AND THE
WRF ARW INDICATED ISOLATED TO SCATTERED CONVECTION LATE THIS EVENING
AND OVERNIGHT. HAVE INCREASED CHANCES FOR RAIN AND DID INCLUDE THUNDER
IN THE MORNING UPDATE.
AS FOR THE HWO...WILL MAKE LAST MINUTE DECISION TO ADD HAIL. IT
APPEARS THAT THE RISK FOR LARGE HAIL WILL BE VERY LOW...BUT COULD
NOT RULE IT OUT SINCE LARGE HAIL WAS REPORTED IN MINNESOTA THIS
AFTERNOON.
ON THURSDAY...WARM FRONT WILL CONTINUE TO PUSH NORTH. TEMPERATURES
WERE INCREASED BY A FEW DEGREES...ESPECIALLY ACROSS THE SOUTH DUE
850MB TEMPERATURES AND BASED ON WHAT IS HAPPENING SOUTH OF THE
WARM FRONT TODAY. VERY LOW HUMIDITIES CAN BE EXPECTED...ESPECIALLY
FROM WISCONSIN RAPIDS TO WAUPACA TO WAUTOMA WHERE THEY SHOULD BE
DOWN TO AROUND 25 PERCENT. CONTINUED CHANCES FOR SHOWERS AND
STORMS ON THURSDAY ACROSS THE NORTH. THE 12Z WRF/GFS DID SPIT OUT
A FEW HUNDREDTHS OF AN INCH ACROSS PORTIONS OF CENTRAL AND EASTERN
WISCONSIN. PER COORDINATION WITH MILWAUKEE...THIS DID NOT SEEM
LIKE A FEASIBLE SCENARIO BASED ON MODEL SOUNDINGS.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS AND
TEMPERATURES ARE THE MAIN FCST CONCERNS.
AN UPPER TROF IS EXPECTED TO MOVE THROUGH THE REGION LATE THURSDAY
NIGHT INTO FRIDAY. BEFORE THE TROF ARRIVES...A WEAK WARM FRONT MAY
STILL BE IN PLACE OVER N WI...SO HAVE POPS CONFINED TO THE NORTHWOODS
DURING THE EVG HOURS. MODELS HAVE TRENDED SLOWER WITH THE ARRIVAL
OF THE UPPER TROF AND ASSOCIATED PCPN...SO WILL ONLY HAVE CHC POPS
FOR PARTS OF NC/C WI LATE THURSDAY NIGHT. THE TROF IS EXPECTED TO
WEAKEN SOMEWHAT AS IT MOVES THROUGH ON FRIDAY...SO SLGT CHC TO
CHC POPS SEEM REASONABLE.
WEAK RIDGING AT THE SFC AND ALOFT SHOULD ALLOW FOR A DRY PERIOD ON
FRIDAY NIGHT. A WEAK INSTABILITY AXIS OVER NC WI ON SATURDAY MAY
ALLOW FOR ISOLD TSTMS...MAINLY DURING THE AFTERNOON.
VERY WARM CONDITIONS WILL PREVAIL OVER THE FORECAST AREA FRIDAY
INTO SATURDAY...WITH HIGH TEMPS IN THE 80S TO LOWER 90S. AS HAS
BEEN THE CASE ALL SUMMER...THE WARMEST TEMPS WILL BE OVER THE
SANDY SOIL AREAS IN CENTRAL WI.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE SATURDAY
NIGHT INTO SUNDAY EVENING. THE GFS/ECMWF OFFER VERY DIFFERENT
SOLUTIONS WITH REGARD TO PCPN/QPF...WITH THE GFS MUCH WETTER THAN
THE ECMWF. SUSPECT THAT THE ECMWF SOLN IS MORE LIKELY...WITH MOST
OF THE UPPER LEVEL ENERGY PASSING NORTH OF THE RGN. THE GFS MODEL
MAY ALSO BE EXHIBITING SOME PROBLEMS WITH CONVECTIVE FEEDBACK...
LEADING TO ENHANCED S/W ENERGY ENERGY APPROACHING FROM THE CENTRAL
PLAINS. WILL STICK WITH THE MODEL BLEND FOR NOW DURING THIS
PERIOD...WITH MID-RANGE POPS.
AFTER THE FRONT MOVES THROUGH...CANADIAN HIGH PRESSURE WILL BUILD
INTO THE REGION FOR MONDAY INTO TUESDAY...RESULTING MORE SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.AVIATION...CONVECTION IS MAIN CONCERN TONIGHT INTO THURSDAY.
A CLUSTER OF SHOWERS AND STORMS FROM MINNEAPOLIS TO NEAR LA
CROSSE THIS AFTERNOON WILL GRADUALLY MOVE EAST INTO CENTRAL
WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING. MODELS
SOLUTIONS VARY FROM THE AREA OF SHOWERS AND STORMS ENDING TO
OTHER MODELS BRINGING IT ACROSS THE AREA THIS EVENING INTO
THE OVERNIGHT. THE COMBINATION OF WARM ADVECTION IN THE LOW
LEVELS OF THE ATMOSPHERE AND STEEP MID LEVEL LAPSE RATES WOULD
SUGGEST ACTIVITY WOULD CONTINUE TO MOVE ACROSS THE AREA TONIGHT
INTO THURSDAY MORNING. THERE WILL MORE THAN LIKELY NEED TO ADD
PRECIPITATION TO THE TAFS THIS AFTERNOON OR WITH THE 00Z TAFS.
MESOSCALE MODELS ALSO SUGGEST ISOLATED TO SCATTERED CONVECTION
OVERNIGHT...WITH THE GREATEST CONCENTRATION OF SHOWERS AND STORMS
NORTH AND WEST OF GREEN BAY AND THE FOX CITIES.
WARM FRONT WILL CONTINUE TO PUSH NORTH ON THURSDAY. THERE IS A
CONTINUED CHANCES FOR SHOWERS AND STORMS NORTH OF A MERRILL TO
STURGEON BAY LINE. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ECKBERG/KIECKBUSCH
AREA FORECAST DISCUSSION...CORRECTED
NWS GREEN BAY WI
220 PM CDT WED AUG 22 2012
.SHORT TERM...TONIGHT AND THURSDAY.
MAIN CONCERN FOR THIS PERIOD WILL BE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND WEDNESDAY...THEN HIGH TEMPERATURES
WEDNESDAY AFTERNOON.
A CLUSTER OF SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHERN
MINNESOTA THIS MORNING AND WAS NOW NEAR THE MINNEAPOLIS AREA. THE
SHOWERS AND STORMS DEVELOPED DUE TO WEAK LOW LEVEL JET...850/700MB
WARM ADVECTION AND STEEP MID LEVEL LAPSE RATES. THESE STORMS PRODUCED
HALF OF A HALF INCH TO HALF DOLLAR SIZE HAIL THIS AFTERNOON. MOST OF
THE BASES OF THESE STORMS WERE AROUND 10 THOUSAND FEET. MODELS DID
NOT HAVE A GOOD HANDLE ON THE DEVELOPMENT OF THIS CLUSTER OF STORMS
AND ALSO DIFFER ON THE EVOLUTION OF THIS CLUSTER OF STORMS AS IT
MOVES EAST INTO WISCONSIN.
THE WRF INDICATES THE 850/700MB WARM ADVECTION WILL MOVE ACROSS
THE AREA TONIGHT WITH THE GREATEST WARM ADVECTION NORTH AND WEST OF
GREEN BAY AND THE FOX VALLEY. DO NOT SEE WHY CONVECTION WOULD END
THIS AFTERNOON AND THIS IS SUPPORTED BY THE LATEST RUC MODEL.
LOOKING AT SOME OF THE MESOSCALE MODELS LIKE THE SPC WRF AND THE
WRF ARW INDICATED ISOLATED TO SCATTERED CONVECTION LATE THIS EVENING
AND OVERNIGHT. HAVE INCREASED CHANCES FOR RAIN AND DID INCLUDE THUNDER
IN THE MORNING UPDATE.
AS FOR THE HWO...WILL MAKE LAST MINUTE DECISION TO ADD HAIL. IT
APPEARS THAT THE RISK FOR LARGE HAIL WILL BE VERY LOW...BUT COULD
NOT RULE IT OUT SINCE LARGE HAIL WAS REPORTED IN MINNESOTA THIS
AFTERNOON.
ON THURSDAY...WARM FRONT WILL CONTINUE TO PUSH NORTH. TEMPERATURES
WERE INCREASED BY A FEW DEGREES...ESPECIALLY ACROSS THE SOUTH DUE
850MB TEMPERATURES AND BASED ON WHAT IS HAPPENING SOUTH OF THE
WARM FRONT TODAY. VERY LOW HUMIDITIES CAN BE EXPECTED...ESPECIALLY
FROM WISCONSIN RAPIDS TO WAUPACA TO WAUTOMA WHERE THEY SHOULD BE
DOWN TO AROUND 25 PERCENT. CONTINUED CHANCES FOR SHOWERS AND
STORMS ON WEDNESDAY ACROSS THE NORTH. THE 12Z WRF/GFS DID SPIT OUT
A FEW HUNDREDTHS OF AN INCH ACROSS PORTIONS OF CENTRAL AND EASTERN
WISCONSIN. PER COORDINATION WITH MILWAUKEE...THIS DID NOT SEEM
LIKE A FEASIBLE SCENARIO BASED ON MODEL SOUNDINGS.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS AND
TEMPERATURES ARE THE MAIN FCST CONCERNS.
AN UPPER TROF IS EXPECTED TO MOVE THROUGH THE REGION LATE THURSDAY
NIGHT INTO FRIDAY. BEFORE THE TROF ARRIVES...A WEAK WARM FRONT MAY
STILL BE IN PLACE OVER N WI...SO HAVE POPS CONFINED TO THE NORTHWOODS
DURING THE EVG HOURS. MODELS HAVE TRENDED SLOWER WITH THE ARRIVAL
OF THE UPPER TROF AND ASSOCIATED PCPN...SO WILL ONLY HAVE CHC POPS
FOR PARTS OF NC/C WI LATE THURSDAY NIGHT. THE TROF IS EXPECTED TO
WEAKEN SOMEWHAT AS IT MOVES THROUGH ON FRIDAY...SO SLGT CHC TO
CHC POPS SEEM REASONABLE.
WEAK RIDGING AT THE SFC AND ALOFT SHOULD ALLOW FOR A DRY PERIOD ON
FRIDAY NIGHT. A WEAK INSTABILITY AXIS OVER NC WI ON SATURDAY MAY
ALLOW FOR ISOLD TSTMS...MAINLY DURING THE AFTERNOON.
VERY WARM CONDITIONS WILL PREVAIL OVER THE FORECAST AREA FRIDAY
INTO SATURDAY...WITH HIGH TEMPS IN THE 80S TO LOWER 90S. AS HAS
BEEN THE CASE ALL SUMMER...THE WARMEST TEMPS WILL BE OVER THE
SANDY SOIL AREAS IN CENTRAL WI.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE SATURDAY
NIGHT INTO SUNDAY EVENING. THE GFS/ECMWF OFFER VERY DIFFERENT
SOLUTIONS WITH REGARD TO PCPN/QPF...WITH THE GFS MUCH WETTER THAN
THE ECMWF. SUSPECT THAT THE ECMWF SOLN IS MORE LIKELY...WITH MOST
OF THE UPPER LEVEL ENERGY PASSING NORTH OF THE RGN. THE GFS MODEL
MAY ALSO BE EXHIBITING SOME PROBLEMS WITH CONVECTIVE FEEDBACK...
LEADING TO ENHANCED S/W ENERGY ENERGY APPROACHING FROM THE CENTRAL
PLAINS. WILL STICK WITH THE MODEL BLEND FOR NOW DURING THIS
PERIOD...WITH MID-RANGE POPS.
AFTER THE FRONT MOVES THROUGH...CANADIAN HIGH PRESSURE WILL BUILD
INTO THE REGION FOR MONDAY INTO TUESDAY...RESULTING MORE SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.AVIATION...CONVECTION IS MAIN CONCERN TONIGHT INTO THURSDAY.
A CLUSTER OF SHOWERS AND STORMS FROM MINNEAPOLIS TO NEAR LA
CROSSE THIS AFTERNOON WILL GRADUALLY MOVE EAST INTO CENTRAL
WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING. MODELS
SOLUTIONS VARY FROM THE AREA OF SHOWERS AND STORMS ENDING TO
OTHER MODELS BRINGING IT ACROSS THE AREA THIS EVENING INTO
THE OVERNIGHT. THE COMBINATION OF WARM ADVECTION IN THE LOW
LEVELS OF THE ATMOSPHERE AND STEEP MID LEVEL LAPSE RATES WOULD
SUGGEST ACTIVITY WOULD CONTINUE TO MOVE ACROSS THE AREA TONIGHT
INTO THURSDAY MORNING. THERE WILL MORE THAN LIKELY NEED TO ADD
PRECIPITATION TO THE TAFS THIS AFTERNOON OR WITH THE 00Z TAFS.
MESOSCALE MODELS ALSO SUGGEST ISOLATED TO SCATTERED CONVECTION
OVERNIGHT...WITH THE GREATEST CONCENTRATION OF SHOWERS AND STORMS
NORTH AND WEST OF GREEN BAY AND THE FOX CITIES.
WARM FRONT WILL CONTINUE TO PUSH NORTH ON THURSDAY. THERE IS A
CONTINUED CHANCES FOR SHOWERS AND STORMS NORTH OF A MERRILL TO
STURGEON BAY LINE. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ECKBERG/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
215 PM CDT WED AUG 22 2012
.SHORT TERM...TONIGHT AND WEDNESDAY
MAIN CONCERN FOR THIS PERIOD WILL BE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TONIGHT AND WEDNESDAY...THEN HIGH TEMPERATURES
WEDNESDAY AFTERNOON.
A CLUSTER OF SHOWERS AND THUNDERSTORMS DEVELOPED ACROSS SOUTHERN
MINNESOTA THIS MORNING AND WAS NOW NEAR THE MINNEAPOLIS AREA. THE
SHOWERS AND STORMS DEVELOPED DUE TO WEAK LOW LEVEL JET...850/700MB
WARM ADVECTION AND STEEP MID LEVEL LAPSE RATES. THESE STORMS PRODUCED
HALF OF A HALF INCH TO HALF DOLLAR SIZE HAIL THIS AFTERNOON. MOST OF
THE BASES OF THESE STORMS WERE AROUND 10 THOUSAND FEET. MODELS DID
NOT HAVE A GOOD HANDLE ON THE DEVELOPMENT OF THIS CLUSTER OF STORMS
AND ALSO DIFFER ON THE EVOLUTION OF THIS CLUSTER OF STORMS AS IT
MOVES EAST INTO WISCONSIN.
THE WRF INDICATES THE 850/700MB WARM ADVECTION WILL MOVE ACROSS
THE AREA TONIGHT WITH THE GREATEST WARM ADVECTION NORTH AND WEST OF
GREEN BAY AND THE FOX VALLEY. DO NOT SEE WHY CONVECTION WOULD END
THIS AFTERNOON AND THIS IS SUPPORTED BY THE LATEST RUC MODEL.
LOOKING AT SOME OF THE MESOSCALE MODELS LIKE THE SPC WRF AND THE
WRF ARW INDICATED ISOLATED TO SCATTERED CONVECTION LATE THIS EVENING
AND OVERNIGHT. HAVE INCREASED CHANCES FOR RAIN AND DID INCLUDE THUNDER
IN THE MORNING UPDATE.
AS FOR THE HWO...WILL MAKE LAST MINUTE DECISION TO ADD HAIL. IT
APPEARS THAT THE RISK FOR LARGE HAIL WILL BE VERY LOW...BUT COULD
NOT RULE IT OUT SINCE LARGE HAIL WAS REPORTED IN MINNESOTA THIS
AFTERNOON.
ON WEDNESDAY...WARM FRONT WILL CONTINUE TO PUSH NORTH. TEMPERATURES
WERE INCREASED BY A FEW DEGREES...ESPECIALLY ACROSS THE SOUTH DUE
850MB TEMPERATURES AND BASED ON WHAT IS HAPPENING SOUTH OF THE
WARM FRONT TODAY. VERY LOW HUMIDITIES CAN BE EXPECTED...ESPECIALLY
FROM WISCONSIN RAPIDS TO WAUPACA TO WAUTOMA WHERE THEY SHOULD BE DOWN
TO AROUND 25 PERCENT. CONTINUED CHANCES FOR SHOWERS AND STORMS ON
WEDNESDAY ACROSS THE NORTH. THE 12Z WRF/GFS DID SPIT OUT A FEW
HUNDREDTHS OF AN INCH ACROSS PORTIONS OF CENTRAL AND EASTERN WISCONSIN.
PER COORDINATION WITH MILWAUKEE...THIS DID NOT SEEM LIKE A
FEASIBLE SCENARIO BASED ON MODEL SOUNDINGS.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS AND
TEMPERATURES ARE THE MAIN FCST CONCERNS.
AN UPPER TROF IS EXPECTED TO MOVE THROUGH THE REGION LATE THURSDAY
NIGHT INTO FRIDAY. BEFORE THE TROF ARRIVES...A WEAK WARM FRONT MAY
STILL BE IN PLACE OVER N WI...SO HAVE POPS CONFINED TO THE NORTHWOODS
DURING THE EVG HOURS. MODELS HAVE TRENDED SLOWER WITH THE ARRIVAL
OF THE UPPER TROF AND ASSOCIATED PCPN...SO WILL ONLY HAVE CHC POPS
FOR PARTS OF NC/C WI LATE THURSDAY NIGHT. THE TROF IS EXPECTED TO
WEAKEN SOMEWHAT AS IT MOVES THROUGH ON FRIDAY...SO SLGT CHC TO
CHC POPS SEEM REASONABLE.
WEAK RIDGING AT THE SFC AND ALOFT SHOULD ALLOW FOR A DRY PERIOD ON
FRIDAY NIGHT. A WEAK INSTABILITY AXIS OVER NC WI ON SATURDAY MAY
ALLOW FOR ISOLD TSTMS...MAINLY DURING THE AFTERNOON.
VERY WARM CONDITIONS WILL PREVAIL OVER THE FORECAST AREA FRIDAY
INTO SATURDAY...WITH HIGH TEMPS IN THE 80S TO LOWER 90S. AS HAS
BEEN THE CASE ALL SUMMER...THE WARMEST TEMPS WILL BE OVER THE
SANDY SOIL AREAS IN CENTRAL WI.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE SATURDAY
NIGHT INTO SUNDAY EVENING. THE GFS/ECMWF OFFER VERY DIFFERENT
SOLUTIONS WITH REGARD TO PCPN/QPF...WITH THE GFS MUCH WETTER THAN
THE ECMWF. SUSPECT THAT THE ECMWF SOLN IS MORE LIKELY...WITH MOST
OF THE UPPER LEVEL ENERGY PASSING NORTH OF THE RGN. THE GFS MODEL
MAY ALSO BE EXHIBITING SOME PROBLEMS WITH CONVECTIVE FEEDBACK...
LEADING TO ENHANCED S/W ENERGY ENERGY APPROACHING FROM THE CENTRAL
PLAINS. WILL STICK WITH THE MODEL BLEND FOR NOW DURING THIS
PERIOD...WITH MID-RANGE POPS.
AFTER THE FRONT MOVES THROUGH...CANADIAN HIGH PRESSURE WILL BUILD
INTO THE REGION FOR MONDAY INTO TUESDAY...RESULTING MORE SEASONABLE
TEMPERATURES AND DRY CONDITIONS.
&&
.AVIATION...CONVECTION IS MAIN CONCERN TONIGHT INTO WEDNESDAY.
A CLUSTER OF SHOWERS AND STORMS FROM MINNEAPOLIS TO NEAR LA
CROSSE THIS AFTERNOON WILL GRADUALLY MOVE EAST INTO CENTRAL
WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING. MODELS
SOLUTIONS VARY FROM THE AREA OF SHOWERS AND STORMS ENDING TO
OTHER MODELS BRINGING IT ACROSS THE AREA THIS EVENING INTO
THE OVERNIGHT. THE COMBINATION OF WARM ADVECTION IN THE LOW
LEVELS OF THE ATMOSPHERE AND STEEP MID LEVEL LAPSE RATES WOULD
SUGGEST ACTIVITY WOULD CONTINUE TO MOVE ACROSS THE AREA TONIGHT
INTO WEDNESDAY MORNING. THERE WILL MORE THAN LIKELY NEED TO ADD
PRECIPITATION TO THE TAFS THIS AFTERNOON OR WITH THE 00Z TAFS.
MESOSCALE MODELS ALSO SUGGEST ISOLATED TO SCATTERED CONVECTION
OVERNIGHT...WITH THE GREATEST CONCENTRATION OF SHOWERS AND STORMS
NORTH AND WEST OF GREEN BAY AND THE FOX CITIES.
WARM FRONT WILL CONTINUE TO PUSH NORTH ON WEDNESDAY. THERE IS A
CONTINUED CHANCES FOR SHOWERS AND STORMS NORTH OF A MERRILL TO
STURGEON BAY LINE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ECKBERG/KIECKBUSCH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1250 PM CDT WED AUG 22 2012
.UPDATE...
HIGH PRESSURE RIDGE OVER WISCONSIN IS KEEPING THE DRY AIR IN PLACE.
SKIES ARE CLEAR ACROSS ALL OF SOUTHERN WI. THUNDERSTORMS IN SOUTH
CENTRAL MINNESOTA ASSOCIATED WITH 850 AND 700MB WARM AIR ADVECTION
ON THE NOSE OF THE 850MB LOW LEVEL JET ARE EXPECTED TO GENERALLY
BREAK APART AS THEY MOVE INTO FAR WESTERN WI THIS AFTERNOON.
THEREFORE...KEPT THE FORECAST DRY.
FOR TONIGHT...TRICKY FORECAST SINCE THERE DOES APPEAR TO BE A SMALL
CHANCE FOR ELEVATED THUNDERSTORMS WITH THE WARM AIR ADVECTION IN OUR
NORTHWEST FORECAST AREA. THERE IS A LOT OF MODEL SPREAD FOR PRECIP
CHANCES TONIGHT. THE LATEST 14Z HRRR NOW FOLLOWS THE IDEA OF THE 12Z
NAM AND SPREADS STORMS INTO THE WESTERN FORECAST AREA THIS EVENING.
OVERALL IT APPEARS THE BETTER CHANCE FOR PRECIP WILL BE TO OUR NORTH
AND WEST...CLOSER TO THE 850MB LOW LEVEL JET AND WARM AIR ADVECTION.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS THROUGH THE FORECAST PERIOD. THERE ARE A LOT OF MODEL
DIFFERENCES...BUT THERE DOES NOT APPEAR TO BE A GOOD CHANCE FOR
STORMS REACHING ANY OF THE TAF SITES TONIGHT. ELEVATED CONVECTION
SHOULD REMAIN TO OUR NORTH AND WEST WITH THE BETTER WARM AIR
ADVECTION AND LOW LEVEL JET.
MODELS ARE GENERATING LIGHT QPF IN THE EASTERN FORECAST AREA THU
AFTERNOON...BUT NOT BUYING IT GIVEN THE LOW LEVEL DRY AIR. THE
MODELS MAY BE HINTING AT MORE WIDESPREAD CUMULUS CLOUD COVER IN
THAT AREA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT WED AUG 22 2012
.SHORT TERM...TODAY THROUGH FRIDAY
314 AM CDT WED AUG 22 2012
MAIN FORECAST CONCERNS ARE ON SLIGHT SHOWER AND THUNDERSTORM CHANCES
TODAY...FOCUS THEN TURNS TO RAIN CHANCES AND TEMPERATURES THURSDAY
INTO FRIDAY.
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW ALOFT ACROSS THE
FORECAST AREA WITH AN UPPER LEVEL TROUGH PUSHING INTO IDAHO AND
WESTERN MONTANA. SURFACE OBSERVATIONS INDICATED A SURFACE LOW OVER
SOUTHEAST SOUTH DAKOTA WITH A WARM FRONT EXTENDING SOUTHEAST THROUGH
SOUTHWEST IOWA...LIFTING NORTHWARD.
THE WARM FRONT IS EXPECTED TO LIFT FROM SOUTH TO NORTH ACROSS THE
FORECAST AREA TODAY INTO THIS EVENING. A WEAK SHORTWAVE WILL PUSH
ACROSS THE REGION AND INTERACT WITH THE BOUNDARY POSSIBLY GENERATING
ISOLATED SHOWERS AND THUNDERSTORM. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE ONGOING ACROSS PORTIONS OF SOUTH CENTRAL
MINNESOTA THIS MORNING...POSSIBLY EDGING INTO SOUTHEAST MINNESOTA.
SHOULD SEE THIS ACTIVITY TAPER OFF AS MOISTURE TRANSPORT WEAKENS.
OVERALL THE LOWER LEVELS OF THE ATMOSPHERE ARE VERY DRY WITH
INVERTED V TYPE SOUNDINGS AND CLOUD BASES AT 10 KFT. WILL BE
INCLUDING A CHANCE OF SHOWERS AND THUNDERSTORM FOR THIS MORNING
ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHEAST MINNESOTA. SLIGHT
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL EXPAND NORTHEAST THIS
AFTERNOON INTO EARLY THIS EVENING INTO PORTIONS OF SOUTHWEST INTO
CENTRAL WISCONSIN.
THE WARM FRONT IS EXPECTED TO LIFT NORTH OF THE INTERSTATE 94
CORRIDOR LATE THIS EVENING WITH ANY LINGERING ISOLATED SHOWER AND
THUNDERSTORM CHANCES GRADUALLY LIFTING TO THE NORTH. FORECAST MODELS
ARE IN AGREEMENT SHOWING THE WARM FRONT LIFTING INTO FAR NORTHERN
WISCONSIN...PLACING THE FORECAST AREA IN THE WARM SECTOR THROUGH
MUCH OF THE DAY ON THURSDAY. RATHER DRY AIR IS EXPECTED TO MOVE INTO
THE REGION WITHIN THE WARM SECTOR AND WITH AFTERNOON MIXING WILL SEE
DEW POINTS PLUMMET INTO THE 40S. FORECAST SOUNDINGS SHOW DEEP MIXING
SO SHOULD SEE TEMPERATURES WARM WELL INTO THE 80S...WITH LOWER 90S
EXPECTED ALONG AND SOUTH OF THE INTERSTATE 90 CORRIDOR. HAVE WARMED
HIGHS A FEW DEGREES FOR THURSDAY AND DROPPED DEW POINTS
SIGNIFICANTLY. IN ADDITION...THURSDAY WILL BE BREEZY WITH A TIGHT
PRESSURE GRADIENT OVER THE AREA...WITH SOUTH/SOUTHWEST WINDS AT 10
TO 20 MPH WITH GUSTS AROUND 30 MPH IN THE OPEN AREAS. WILL HAVE
TO CLOSELY MONITOR CLOUD TRENDS IN THE FORECAST MODELS THE NEXT
SET OF RUNS WITH THE POTENTIAL FOR MID AND HIGH CLOUDS TO LINGER
THROUGH EARLY AFTERNOON. THE WINDS AND FALLING DEW POINTS COULD
CREATE FIRE WEATHER CONCERNS THURSDAY AFTERNOON...BEFORE CLOUDS
SPILL IN LATE IN THE AFTERNOON FROM A TROUGH APPROACHING FROM
WESTERN MINNESOTA.
22.00 FORECAST MODELS HAVE REALLY SLOWED THE ARRIVAL OF
PRECIPITATION THURSDAY INTO FRIDAY. THE TROUGH WILL MOVE SLOWLY
ACROSS MINNESOTA THROUGH THE DAY ON THURSDAY PUSHING ACROSS THE
MISSISSIPPI RIVER LATE THURSDAY NIGHT INTO FRIDAY MORNING. HAVE
CONTINUED THE TREND OF SLOWING THE ARRIVAL OF SHOWERS AND
THUNDERSTORMS UNTIL LATE THURSDAY AFTERNOON INTO THURSDAY
EVENING...WITH THE BULK OF THE ACTIVITY IMPACTING LOCATIONS ALONG
AND WEST OF THE MISSISSIPPI RIVER IN THE LATE EVENING INTO EARLY
FRIDAY MORNING. HAVE INCREASED PRECIPITATION CHANCES LATE THURSDAY
NIGHT INTO EARLY FRIDAY MORNING WHEN THE STRONGEST MOISTURE
TRANSPORT IS FOCUSED INTO THE AREA...ESPECIALLY AT THE 850 MB
LEVEL. THE TROUGH WILL SHIFT EAST OF THE REGION FRIDAY AFTERNOON
WITH SHOWERS AND THUNDERSTORMS TAPERING OFF. WARM SOUTHERLY FLOW
WILL CONTINUE ACROSS THE AREA FRIDAY AFTERNOON INTO FRIDAY NIGHT.
TWO PIECES OF ENERGY TO KEEP A CLOSE WATCH ON FRIDAY NIGHT INTO
SATURDAY. THE FIRST IS A POTENT TROUGH MOVING ALONG THE U.S. CANADA
BORDER...JUST BRUSHING NORTHERN MONTANA AND NORTH DAKOTA PUSHING
EAST. THE SECOND FEATURE IS A TROUGH MOVING OUT OF THE CENTRAL
PLAINS HEADING TOWARD THE MIDDLE MISSISSIPPI RIVER VALLEY.
.LONG TERM...SATURDAY THROUGH TUESDAY
314 AM CDT WED AUG 22 2012
22.00 MODELS STRUGGLING A BIT ON HANDLING THE TROUGH MOVING ALONG
THE U.S. CANADA BORDER AND THE WAVE PUSHING ACROSS THE CENTRAL
PLAINS. THE ECMWF KEEPS THESE TWO FEATURES SEPARATE LIFTING THE
NORTHERN STREAM TROUGH NORTH OVER HUDSONS BAY SATURDAY INTO
SUNDAY...WITH THE SOUTHERN TROUGH IMPACTING THE MIDDLE MISSISSIPPI
RIVE VALLEY REGION. THE GFS ATTEMPTS TO PHASE THESE TWO FEATURES
WHICH WOULD FAVOR HIGHER PRECIPITATION CHANCES ACROSS THE AREA.
GIVEN THE FORECAST MODEL DIFFERENCES WILL LEAN TOWARD A MODEL
CONSENSUS BLEND THROUGH THE WEEKEND...WITH SHOWER AND
THUNDERSTORMS CHANCES SATURDAY NIGHT INTO SUNDAY. A BROAD UPPER
RIDGE LOOKS TO BUILD INTO THE WESTERN CONUS BY EARLY NEXT WEEK
PROVIDING DRY CONDITIONS AND SEASONABLE TEMPERATURES ACROSS THE
FORECAST AREA.
&&
.AVIATION...
625 AM CDT WED AUG 22 2012
WINDS AND DRY AIR HAVE CONSPIRED TO PUT THE BRAKES ON RIVER VALLEY
FOG FORMATION THIS MORNING. BUFKIT RAP SOUNDING POINTS TO 15 KTS OF
WIND BY 200 FT...WHILE THE 00Z T/TD SPREAD WAS 32 F. BOTH ARE
UNFAVORABLE FOR DENSE FOG. A GOOD AMOUNT OF BREEZE AT THE ARX OFFICE
ON THE BLUFF OVERLOOKING THE LA CROSSE VALLEY TOO...AND NO STRATUS
EVIDENT ON THE RIVER. SO...WILL STAY WITH P6SM AT KLSE.
OFF TO THE WEST LOW LEVEL WARM AIR ADVECTION AND THE LOW LEVEL
JET/MOISTURE TRANSPORT WERE HELPING SPARK A FEW SHRA/TS OVER
SOUTHWEST/SOUTHERN MN. THE JET AND MOISTURE TRANSPORT WILL WEAKEN
THIS MORNING...BUT THE WARM AIR ADVECTION LINGERS...AS WILL SOME
FRONTOGENETIC FORCING. IN ADDITION...SOME ELEVATED INSTABILITY WILL
BUILD FOR THE AFTERNOON. ITS WEAK DYNAMICALLY...BUT THERE HAS BEEN
ENOUGH TO DRIVE THE CURRENT PCPN...AND EXPECT ENOUGH TO CONTINUE
ISOLD/SCT THREAT INTO THIS EVENING. THE SATURATION IS A LOFT...AND
MOST BASES WILL BE CONFINED FROM 8 TO 12 KFT. WITH THE MORE MISS
THAN HIT ASPECT TO THE SHRA/TS...HAVE OPTED TO LEAVE OUT OF THE TAFS
FOR NOW.
WINDS WILL BECOME MORE SOUTHERLY TODAY...AND START TO INCREASE ON
THURSDAY AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING
COLD FRONT. DEEP MIXING UP TO 750 MB AND UNIDIRECTIONAL WINDS A LOFT
SHOULD LEAD TO WIND GUSTS AROUND 25 MPH AT KRST THU AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CDT WED AUG 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 PM CDT TUE AUG 21 2012
.SHORT TERM...THROUGH THURSDAY NIGHT
230 PM CDT TUE AUG 21 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES WEDNESDAY THROUGH
THURSDAY NIGHT.
SURFACE ANALYSIS THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED OVER
EASTERN IOWA INTO CENTRAL WISCONSIN.
THE FIRST CONCERN IS WHETHER ANY VALLEY FOG WILL FORM AGAIN
TONIGHT. THE SURFACE HIGH WILL BE PULLING OFF TO THE SOUTHEAST AND
SHOULD BE CENTERED OVER INDIANA BY LATE TONIGHT. BOTH THE 21.12Z
NAM AND GFS SUGGEST A WARM FRONT WILL DEVELOP IN THE RETURN FLOW
FROM SOUTH DAKOTA INTO MISSOURI. AS THIS OCCURS...BOTH MODELS
ACTUALLY SHOW A LITTLE BIT OF RIDGING DEVELOPING NORTH OF THE
FRONT AND OVER THE AREA. THIS SHOULD ALLOW THE SURFACE WINDS TO
DECOUPLE ONCE AGAIN AND DEW POINTS SHOULD RECOVER INTO THE UPPER
40S. SKIES WILL BE CLEAR OVERNIGHT SO PLENTY OF POSITIVES FOR THE
FOG. BOTH THE NAM AND 21.17Z RAP BUFKIT SOUNDING FOR KLSE SHOW
SOUTHWEST WINDS AROUND 20 KNOTS JUST ABOVE THE SURFACE UP THROUGH
ABOUT 3 OR 4 THOUSAND FEET. THIS IS VERY SIMILAR TO A COUPLE OF
NIGHTS AGO EXPECT THE WINDS ARE ABOUT 180 DEGREES DIFFERENT IN
DIRECTION AND MAYBE A LITTLE STRONGER TONIGHT. SOME FOG DID FORM
IN THESE SIMILAR CONDITIONS SATURDAY MORNING SO PLAN TO INCLUDE A
MENTION OF PATCHY FOG.
THE NEXT CONCERN IS WHETHER ANY RAIN WILL FORM WEDNESDAY AND
WEDNESDAY NIGHT IN THE RETURN FLOW. MODEL DIFFERENCES CONTINUE
WITH THE NAM AND GFS STILL SHOWING SOME RAIN DEVELOPING WHILE THE
21.00Z ECMWF REMAINS DRY. WHETHER THIS RAIN DEVELOPS OR NOT
DEPENDS ON HOW MUCH LOW LEVEL THERMODYNAMICS COME INTO PLAY. THE
NAM CONTINUES TO BE THE STRONGEST WITH THIS FORCING SHOWING WEAK
FRONTOGENESIS IN THE 1000-500 MB LAYER NORTH OF THE WARM FRONT.
THE ECMWF ALSO HAS A LITTLE BIT OF FRONTOGENESIS BUT ONLY UP
THROUGH 700 MB. THE BIG DIFFERENCE COMES IN THE ISENTROPIC
RESPONSE. THE NAM GENERATES UP TO 10 UBAR/S ON THE 310K SURFACE
WHILE THE GFS ONLY HAS ABOUT 3 UBAR/S AND THE ECMWF HAS BETWEEN 1
AND 2 UBAR/S. IF THIS RAIN DOES DEVELOP...THE NAM BUFKIT SOUNDINGS
SHOW CLOUD BASES WOULD BE ABOUT 10K FEET WITH LOTS OF DRY AIR
BELOW. WOULD NOT EXPECT MUCH MORE THAN SOME SPRINKLES OR A QUICK
SHOWER WITH A COUPLE HUNDREDTHS QPF.
THE MODEL DIFFERENCES CONTINUE INTO THURSDAY AND THURSDAY NIGHT AS
WELL. THE SHORT WAVE TROUGH COMING ONTO THE PACIFIC NORTHWEST
COAST TODAY WILL TOP THE ROCKIES AND START MOVING ACROSS THE UPPER
MIDWEST. THE ECMWF HAS BEEN VERY CONSISTENT SHOWING THE FILLING
UPPER LEVEL LOW WITH THIS SYSTEM TO BE MOVING NORTHEAST INTO
CENTRAL CANADA WHILE THE SHORT WAVE TROUGH COMES THROUGH WITH A
POSITIVE TILT. THE NAM AND GFS ARE SUGGESTING THAT A PIECE OF
ENERGY WILL BREAK OUT OF THE MEAN LONG WAVE TROUGH AXIS OR A NEW
SHORT WAVE TROUGH DEVELOPS IN THE LEE OF THE ROCKIES WEDNESDAY.
THESE MODELS THEN BRING THIS SHORT WAVE TROUGH ACROSS THE AREA
WITH A NEUTRAL TO NEGATIVE TILT AND QUICKER THAN THE POSITIVE
TILT OF THE ECMWF. AT THIS POINT...CONFIDENCE ON WHICH SOLUTION
WILL VERIFY IS NOT HIGH SO HAVE TRIED TO COMPROMISE BETWEEN THE
TWO WITH A SLIGHT NOD TOWARD THE ECMWF SOLUTION. WILL SHOW A SMALL
CHANCE OF RAIN ACROSS THE FAR NORTH THURSDAY MORNING AHEAD OF THE
ADVANCING WARM FRONT AND THEN 20 TO 30 PERCENT CHANCES DURING THE
AFTERNOON ACROSS THE WEST AND NORTH AS THE FORCING STARTS TO
INCREASE AHEAD OF THE APPROACHING SYSTEM. AS THE SHORT WAVE TROUGH
THEN COMES INTO LATER THURSDAY...IT SHOULD PRODUCE AROUND 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER. NOT MUCH OF
SURFACE REFLECTION WITH THIS SYSTEM SO ONLY SOME WEAK
FRONTOGENESIS IN THE 1000-850 MB LAYER. SOME WEAK UP GLIDE OF 1-2
UBAR/S SHOULD CONTINUE ON THE 310K SURFACE ALONG WITH GETTING
INTO THE EASTERN AND CONVERGENT SIDE OF THE MOISTURE TRANSPORT
AXIS. ALL THIS FORCING LOOKS TO BE AT ITS STRONGEST THURSDAY NIGHT
ACROSS THE NORTH AND DID INCREASE THE RAIN CHANCE TO AROUND 60
THERE.
.LONG TERM...FRIDAY THROUGH TUESDAY
230 PM CDT TUE AUG 21 2012
THE RAIN THAT DEVELOPS THURSDAY/THURSDAY NIGHT SHOULD BE COMING TO
AN END FRIDAY INTO FRIDAY NIGHT AS THE SHORT WAVE TROUGH MOVES
PAST THE AREA. THE NEXT PIECE OF ENERGY WILL QUICKLY APPROACH FROM
THE WEST COAST WITH THE UPPER LEVEL LOW AGAIN MOVING ACROSS CANADA
ALLOWING A SOUTHWEST FLOW ALOFT TO DEVELOP ACROSS THE UPPER
MIDWEST. INITIALLY THE MODELS ARE IN GOOD AGREEMENT THAT A SHORT
WAVE TROUGH WILL BE IN THIS SOUTHWEST FLOW OVER THE MID PLAINS
STATES SATURDAY NIGHT BUT THEN DIVERGE AS THEY START TO LIFT THIS
WAVE NORTHEAST. THE GFS FLATTENS THIS WAVE OUT AND LIFTS IT
THROUGH QUICKER THAN EITHER THE 21.12Z GEM OR ECMWF. THE ECMWF IS
THE STRONGEST AND SLOWEST LIFTING THIS WAVE TO THE NORTHEAST. THE
DIFFERENCES COULD BE STEMMING FROM THE WIDE RANGE OF SOLUTIONS
THAT ARE SHOWING UP WITH A POTENTIAL TROPICAL SYSTEM APPROACHING
THE SOUTHEAST U.S. AND FOR NOW HAVE STAYED WITH THE MODEL
CONSENSUS GRIDS WITH 30 TO 50 PERCENT RAIN CHANCES SATURDAY NIGHT
THROUGH SUNDAY NIGHT WITH THE SYSTEM THEN MOVING PAST MONDAY.
&&
.AVIATION...THROUGH 06Z THURSDAY
1144 PM CDT TUE AUG 21 2012
MAIN CONCERN REMAINS VALLEY FOG POTENTIAL AT KLSE THIS MORNING.
A WEAK PRESSURE GRADIENT RESULTING FROM HIGH PRESSURE CENTERED
NEAR CHICAGO KEPT WINDS FAIRLY LIGHT LAST EVENING. HOWEVER...THE
HIGH CONTINUES TO DRIFT OFF TO THE EAST...WHICH IN TURN WILL
INCREASE WINDS ABOVE THE SURFACE. THE WIND INCREASE IS ALREADY
BEING FELT AT THE OFFICE HERE ON TOP OF THE BLUFF. THESE WINDS IN
CONJUNCTION WITH DRY AIR IN PLACE AND LACK OF RECENT PRECIPITATION
SHOULD HELP MINIMIZE VALLEY FOG OR STRATUS FROM DEVELOPING. STILL
DO NOT HAVE CONFIDENCE OF COMPLETELY PULLING VCFG OR SCATTERED
LIFR CLOUDS BETWEEN THE 11-14Z TIME PERIOD...GIVEN COOLING AND
SOME MOISTENING THAT HAS OCCURRED. HOWEVER...IT SEEMS THAT VFR
CONDITIONS ARE FAIRLY CERTAIN.
OTHERWISE...SOUTHERLY FLOW WILL CONTINUE TO INCREASE TODAY AS A
WARM FRONT LIFTS FROM NEBRASKA TO THE TAF SITES. GUSTS AT KRST
COULD TOP OUT AROUND 18 KT OR SO DURING THE AFTERNOON WITH DAYTIME
MIXING. ALTOSTRATUS DEVELOPMENT IS LIKELY AS WELL AS THE FRONT
APPROACHES. IT APPEARS ANY PRECIPITATION OUT OF THIS CLOUD DECK
WOULD BE SPRINKLES AT BEST...NOT ENOUGH TO MENTION IN THE TAF.
ONE LAST ITEM TO WATCH IS POTENTIAL FOR LOW LEVEL WIND SHEAR AT
KLSE APPROACHING 06Z THURSDAY AS THE WARM FRONT LIFTS NORTH OF THE
TAF SITES. THERE ARE SOME SUGGESTIONS OF A 30 KT SOUTHWEST LOW
LEVEL JET DEVELOPING AT 1000 FT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CDT TUE AUG 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
256 AM CDT FRI AUG 24 2012
.DISCUSSION...
UPDATE...
1043 PM
FOR REST OF TONIGHT...
NO SIGNIFICANT CHANGES MADE TO FORECAST GRIDS AND DERIVED TEXT
PRODUCTS THOUGH DID DO SOME TWEAKING FOR RECENT TRENDS.
DURING THE LATER AFTERNOON TMKE RADAR DETECTED AN INCREASINGLY
DEFINED LINE OF LOW LEVEL CONVERGENCE FROM JUST OFFSHORE OF
HIGHWOOD AND LAKE BLUFF IN SOUTHEAST LAKE CO. IL BOWING OUT OVER
THE LAKE THEN CURVING BACK TO THE SHORELINE NEAR PORT WASHINGTON
IN EAST CENTRAL OZAUKEE CO. WI.
WHILE THE RUC13 HAS SHOWN SURFACE CONVERGENCE ALONG AND JUST
INLAND IN THIS AREA DUE TO A MODEST LAKE BREEZE...THE HRR3
PLACED THIS LINEAR CONVERGENT ZONE...DUE TO SPEED CONVERGENCE PER
THIS MODEL...MUCH BETTER.
SURFACE/LOW LEVEL CONVERGENCE COMBINED WITH WEAK LOW LEVEL WARM
AIR ADVECTION AND VERY MODEST MID LEVEL COOLING AND A VERY MINOR
DISTURBANCE MOVING EAST ACROSS SOUTHERN WI AND NORTHERN IL DURING
THE LATE AFTERNOON THROUGH MID EVENING COMBINED TO ALLOW CAPE
VALES TO GROW AND SHOWERS TO FORM ALONG THIS LINE. WHILE THE
SOUTHERN EXTENT OF THESE SHOWERS HAS BEEN MOVING NORTHWARD AND
WEAKENING DURING THE MID TO LATE EVENING... AT THE SAME TIME
ANOTHER SIMILAR LINE HAS APPEARED BETWEEN THE SAME END POINTS BUT
BOWING ALL THE WAY OUT TO MID LAKE OFF OF RAC AND MKE. A FEW WEAK
SHOWERS WERE ALONG THIS LINE.
PREMISED ON THE HRR CONTINUING TO DEPICT THE LINEAR CONVERGENCE
ZONE...THE AREA OF CONVERGENCE WILL SHIFT SOUTH TO OFF OF THE IL
SHORE BEFORE WEAKENING AS IT DRIFTS OUT TOWARD MID LAKE BY 06Z.
THUS THE THREAT OF SHOWERS WITH THESE FEATURES LOOKS TO BE LOW AT
BEST.
A LONE SHOWER MOVED INTO SOUTHERN LASALLE CO. EARLY THIS EVENING
THEN DISSIPATED AS IT CONTINUE TO THE NORTHEAST. THIS ISOLATED
SHOWER WAS A RESULT OF THE INCREASED LIFT ASSOCIATED WITH THE
MINOR SHORT WAVE MOVING OVER THE NORTHERN END OF AN AREA OF WELL
DEFINED MODERATE CU WITH THE LOSS OF HEATING RESULTING IN ITS
DEMISE.
FOR THE OVERNIGHT...LATEST RUNS OF NAM...RUC AND HRR ALL KEEP THE
LOCAL FORECAST AREA DRY WITH THE RAIN FALLING FROM EASTERN WI
SOUTHWESTWARD ACROSS IA. WITH A STRONGER SHORT WAVE TROUGH MOVING
EAST ACROSS MN AND FAR NORTHERN IA AT LATE EVENING AND PROGGED TO
CONTINUE EAST HAVE RETAINED THE SLIGHT CHANCE POPS ACROSS THE
NORTHERN PORTION OF THE FORECAST AREA...AND WITH THE TROUGH TO
REACH FAR EASTERN WI AND FAR NORTHEAST IL BY EARLY TO MID MORNING
HAVE LEFT THE LOW POPS DURING FRI AS IS.
TRS
//PREV DISCUSSION...
344 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES THIS FORECAST PERIOD ARE WITH
CLOUD TRENDS THIS EVENING AND TONIGHT AS WELL AS FOR A SLIGHT
CHANCE OF LIGHT SHOWERS TONIGHT.
RELATIVELY QUIET BUT WARM CONDITIONS CURRENTLY ACROSS THE
CWA...WITH SOME MID/HIGH LEVEL CLOUD COVER PASSING OVERHEAD. AS
SEVERAL MID LEVEL FEATURES CONTINUE TO SHIFT EAST THIS
EVENING...SOUTHWEST MID LEVEL FLOW WILL ALLOW FOR A CONTINUED
SETUP FOR WAA TO OCCUR. ALTHOUGH THIS WAA/ASCENT WILL BE FAIRLY
WEAK...IT SHOULD BE ENOUGH TO OVERCOME SOME DRIER AIR AND ALLOW
FOR REDEVELOPMENT OF MID LEVEL CLOUDS ACROSS MUCH OF THE REGION.
ALTHOUGH NOT EXACTLY THE SAME SETUP FROM THIS MORNING...A SIMILAR
SITUATION WITH PARTLY CLOUDY/CLOUD SKIES AND SOME LIGHT SHOWERS
COULD ONCE AGAIN OCCUR...ESPECIALLY WITH SOME WEAK MID LEVEL
RIPPLES PASSING OVERHEAD AS WELL AS A LIFTING FRONTAL BOUNDARY. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT SHOWERS TONIGHT.
THUNDER SHOULD BE NONEXISTENT ONCE AGAIN AS BETTER FORCING WILL BE
TIED MORE TOWARD A STRONGER WAVE FURTHER TO THE NORTH ACROSS
WISCONSIN TONIGHT. AS THIS WAVE SHIFTS EAST OF THE REGION FRIDAY
MORNING...ANY PRECIP/CLOUD COVER WILL EXIT AND DIMINISH MAKING WAY
FOR PARTLY CLOUDY SKIES. WITH THERMAL AXIS SHIFTING
OVERHEAD...TEMPS SHOULD RISE FAIRLY EASILY TOMORROW WITH HIGH
TEMPERATURES IN THE LOWER 90S EXPECTED. WITH SOME LOCATIONS IN THE
WESTERN CWA ALREADY OBSERVING LOWER 90S TODAY...IT WOULD NOT BE
OUT OF THE QUESTION FOR SOME MID 90S TO OCCUR AS WELL. DESPITE
THIS WARM UP...LOW HUMIDITY AND SOME SUNSHINE WILL HELP TO PROVIDE
ANOTHER PLEASANT DAY. HAVE ALSO MAINTAINED LOWER 90S INTO SATURDAY
WITH REALLY NO CHANGE IN THE OVERALL SETUP EXPECTED.
THE NEXT BEST CHANCE FOR PRECIP IS STILL APPEARING TO BE LATE IN
THE WEEKEND AS A WAVE EJECTS OUT OF THE CENTRAL PLAINS. THIS
SHOULD INDUCE SOME DECENT PRESSURE FALLS AND HELP THIS SYSTEM WRAP
SOME GOOD MOISTURE INTO IT. WITH GUIDANCE STILL VARYING ON ITS
OVERALL EVOLUTION...HAVE NOT GONE TOO HIGH WITH POPS FOR SUNDAY
BUT DID INCREASE TO HIGH CHANCE POPS FOR MOST OF THE CWA ON SUNDAY
WITH MOST GUIDANCE SPEEDING UP THIS SYSTEM. THIS SYSTEM WILL NEED
TO CONTINUE BE MONITORED...DUE TO THE OVERALL STRENGTH OF THE
CONVECTIVE POTENTIAL STILL UNKNOWN AS WELL AS CHANCES FOR SOME
DECENT RAINFALL.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* 30-35 KT SOUTHWESTERLY FLOW AT 1000-1500 FT THROUGH 13Z.
* SMALL CHANCE FOR ISOLATED SHRA THIS AFTERNOON AND EVENING.
//DISCUSSION...UPDATED 06Z...
THE TERMINALS TODAY WILL REMAIN BETWEEN HIGH PRESSURE CENTERED
ACROSS THE NORTHEAST AND A WEAKENING LOW PRESSURE TROUGH MOVING
FROM MN TO THE UPPER GREAT LAKES. WARM AIR ADVECTION THROUGH THE
MORNING WILL KEEP MID-LEVEL CLOUD COVER DEVELOPING...AS WELL AS
SOME STIFF SSW WINDS NOT FAR OFF THE DECK /1000-1500 FT/. AN
AMDAR FLIGHT FROM RFD INDICATED 31 KT AT 1500 FT AND THESE WINDS
ARE LIKELY TO COME UP SOME BEFORE DAYBREAK AS WELL AS EXPAND
EASTWARD. AS THE WEAK SURFACE TROUGH MOVES EASTWARD AND BEGINS TO
WASH OUT...THERE WILL BE SOME WEAK INSTABILITY POOLING AHEAD OF
THIS ACROSS EASTERN IL/NW IN. ALSO...UPPER LEVEL DISTURBANCES
ALBEIT WEAK MOVING OVER THE AREA MAY JUST BE ENOUGH TO RENDER A
COUPLE STRAY SHOWERS. SOUTH WINDS WILL SEE SOME GUSTINESS
TODAY...MAINLY IN THE 15 TO 20 KT RANGE. SOUTHERLY WINDS WILL
CONTINUE ON SATURDAY WITH NO PRECIPITATION EXPECTED.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN 30-35 KT SOUTHWESTERLY FLOW AT 1000-1500 FT
THROUGH 13Z WITH MEDIUM CONFIDENCE IN THIS STAYING UNDER TRUE
LLWS.
* LOW CONFIDENCE IN THE DEVELOPMENT OF ANY AFTERNOON SHRA BUT HIGH
CONFIDENCE IF ANY WERE TO DEVELOP THEY WOULD BE ISOLATED.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR. WX NIL.
SUNDAY...CHANCE TSRA. OTHERWISE...VFR.
MONDAY...CHANCE TSRA EARLY. OTHERWISE...VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
MTF/KJB
&&
.MARINE...
256 AM CDT
SOUTHERLY FLOW WILL PREVAIL ACROSS THE LAKE INTO THE LATTER PART
OF THE WEEKEND...WITH STAGNANT HIGH PRESSURE OVER THE NORTHEAST
CONUS AND DEVELOPING LOW PRESSURE ACROSS SOUTHERN CANADA. AN
INITIAL WEAK AREA OF LOW PRESSURE THIS MORNING WILL MOVE NORTHEAST
ACROSS WESTERN LAKE SUPERIOR...AND THIS SHOULD RENDER WINDS TO
NEAR 30 KT AND WAVES TO 8 FT AT TIMES ACROSS THE NORTHERN PART OF
THE LAKE. THIS MAY ALSO PROVIDE SOME SCATTERED
THUNDERSTORMS...AGAIN MAINLY ACROSS THE NORTH. THE LOW ACROSS
SOUTHERN CANADA WILL DEEPEN AND MOVE NORTHEAST INTO THE
WEEKEND...STEERING A COLD FRONT EASTWARD ACROSS LAKE MICHIGAN MOST
LIKELY ON SUNDAY NIGHT. RAIN...POTENTIALLY WITH
THUNDERSTORMS...LOOK TO MOVE EAST ACROSS THE LAKE WITH THIS
FEATURE. THIS SHOULD BE AIDED BY A WEAK SURFACE LOW ALONG THE
SOUTHERN PORTION OF THIS FRONT. WHILE WINDS ARE ANTICIPATED TO
TURN WESTERLY AND EVENTUALLY NORTHERLY BEHIND THE FRONT DURING
MONDAY...SPEEDS ARE EXPECTED TO REMAIN AT OR BELOW 15 KT.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1247 AM CDT FRI AUG 24 2012
.DISCUSSION...
UPDATE...
1043 PM
FOR REST OF TONIGHT...
NO SIGNIFICANT CHANGES MADE TO FORECAST GRIDS AND DERIVED TEXT
PRODUCTS THOUGH DID DO SOME TWEAKING FOR RECENT TRENDS.
DURING THE LATER AFTERNOON TMKE RADAR DETECTED AN INCREASINGLY
DEFINED LINE OF LOW LEVEL CONVERGENCE FROM JUST OFFSHORE OF
HIGHWOOD AND LAKE BLUFF IN SOUTHEAST LAKE CO. IL BOWING OUT OVER
THE LAKE THEN CURVING BACK TO THE SHORELINE NEAR PORT WASHINGTON
IN EAST CENTRAL OZAUKEE CO. WI.
WHILE THE RUC13 HAS SHOWN SURFACE CONVERGENCE ALONG AND JUST
INLAND IN THIS AREA DUE TO A MODEST LAKE BREEZE...THE HRR3
PLACED THIS LINEAR CONVERGENT ZONE...DUE TO SPEED CONVERGENCE PER
THIS MODEL...MUCH BETTER.
SURFACE/LOW LEVEL CONVERGENCE COMBINED WITH WEAK LOW LEVEL WARM
AIR ADVECTION AND VERY MODEST MID LEVEL COOLING AND A VERY MINOR
DISTURBANCE MOVING EAST ACROSS SOUTHERN WI AND NORTHERN IL DURING
THE LATE AFTERNOON THROUGH MID EVENING COMBINED TO ALLOW CAPE
VALES TO GROW AND SHOWERS TO FORM ALONG THIS LINE. WHILE THE
SOUTHERN EXTENT OF THESE SHOWERS HAS BEEN MOVING NORTHWARD AND
WEAKENING DURING THE MID TO LATE EVENING... AT THE SAME TIME
ANOTHER SIMILAR LINE HAS APPEARED BETWEEN THE SAME END POINTS BUT
BOWING ALL THE WAY OUT TO MID LAKE OFF OF RAC AND MKE. A FEW WEAK
SHOWERS WERE ALONG THIS LINE.
PREMISED ON THE HRR CONTINUING TO DEPICT THE LINEAR CONVERGENCE
ZONE...THE AREA OF CONVERGENCE WILL SHIFT SOUTH TO OFF OF THE IL
SHORE BEFORE WEAKENING AS IT DRIFTS OUT TOWARD MID LAKE BY 06Z.
THUS THE THREAT OF SHOWERS WITH THESE FEATURES LOOKS TO BE LOW AT
BEST.
A LONE SHOWER MOVED INTO SOUTHERN LASALLE CO. EARLY THIS EVENING
THEN DISSIPATED AS IT CONTINUE TO THE NORTHEAST. THIS ISOLATED
SHOWER WAS A RESULT OF THE INCREASED LIFT ASSOCIATED WITH THE
MINOR SHORT WAVE MOVING OVER THE NORTHERN END OF AN AREA OF WELL
DEFINED MODERATE CU WITH THE LOSS OF HEATING RESULTING IN ITS
DEMISE.
FOR THE OVERNIGHT...LATEST RUNS OF NAM...RUC AND HRR ALL KEEP THE
LOCAL FORECAST AREA DRY WITH THE RAIN FALLING FROM EASTERN WI
SOUTHWESTWARD ACROSS IA. WITH A STRONGER SHORT WAVE TROUGH MOVING
EAST ACROSS MN AND FAR NORTHERN IA AT LATE EVENING AND PROGGED TO
CONTINUE EAST HAVE RETAINED THE SLIGHT CHANCE POPS ACROSS THE
NORTHERN PORTION OF THE FORECAST AREA...AND WITH THE TROUGH TO
REACH FAR EASTERN WI AND FAR NORTHEAST IL BY EARLY TO MID MORNING
HAVE LEFT THE LOW POPS DURING FRI AS IS.
TRS
//PREV DISCUSSION...
344 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES THIS FORECAST PERIOD ARE WITH
CLOUD TRENDS THIS EVENING AND TONIGHT AS WELL AS FOR A SLIGHT
CHANCE OF LIGHT SHOWERS TONIGHT.
RELATIVELY QUIET BUT WARM CONDITIONS CURRENTLY ACROSS THE
CWA...WITH SOME MID/HIGH LEVEL CLOUD COVER PASSING OVERHEAD. AS
SEVERAL MID LEVEL FEATURES CONTINUE TO SHIFT EAST THIS
EVENING...SOUTHWEST MID LEVEL FLOW WILL ALLOW FOR A CONTINUED
SETUP FOR WAA TO OCCUR. ALTHOUGH THIS WAA/ASCENT WILL BE FAIRLY
WEAK...IT SHOULD BE ENOUGH TO OVERCOME SOME DRIER AIR AND ALLOW
FOR REDEVELOPMENT OF MID LEVEL CLOUDS ACROSS MUCH OF THE REGION.
ALTHOUGH NOT EXACTLY THE SAME SETUP FROM THIS MORNING...A SIMILAR
SITUATION WITH PARTLY CLOUDY/CLOUD SKIES AND SOME LIGHT SHOWERS
COULD ONCE AGAIN OCCUR...ESPECIALLY WITH SOME WEAK MID LEVEL
RIPPLES PASSING OVERHEAD AS WELL AS A LIFTING FRONTAL BOUNDARY. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT SHOWERS TONIGHT.
THUNDER SHOULD BE NONEXISTENT ONCE AGAIN AS BETTER FORCING WILL BE
TIED MORE TOWARD A STRONGER WAVE FURTHER TO THE NORTH ACROSS
WISCONSIN TONIGHT. AS THIS WAVE SHIFTS EAST OF THE REGION FRIDAY
MORNING...ANY PRECIP/CLOUD COVER WILL EXIT AND DIMINISH MAKING WAY
FOR PARTLY CLOUDY SKIES. WITH THERMAL AXIS SHIFTING
OVERHEAD...TEMPS SHOULD RISE FAIRLY EASILY TOMORROW WITH HIGH
TEMPERATURES IN THE LOWER 90S EXPECTED. WITH SOME LOCATIONS IN THE
WESTERN CWA ALREADY OBSERVING LOWER 90S TODAY...IT WOULD NOT BE
OUT OF THE QUESTION FOR SOME MID 90S TO OCCUR AS WELL. DESPITE
THIS WARM UP...LOW HUMIDITY AND SOME SUNSHINE WILL HELP TO PROVIDE
ANOTHER PLEASANT DAY. HAVE ALSO MAINTAINED LOWER 90S INTO SATURDAY
WITH REALLY NO CHANGE IN THE OVERALL SETUP EXPECTED.
THE NEXT BEST CHANCE FOR PRECIP IS STILL APPEARING TO BE LATE IN
THE WEEKEND AS A WAVE EJECTS OUT OF THE CENTRAL PLAINS. THIS
SHOULD INDUCE SOME DECENT PRESSURE FALLS AND HELP THIS SYSTEM WRAP
SOME GOOD MOISTURE INTO IT. WITH GUIDANCE STILL VARYING ON ITS
OVERALL EVOLUTION...HAVE NOT GONE TOO HIGH WITH POPS FOR SUNDAY
BUT DID INCREASE TO HIGH CHANCE POPS FOR MOST OF THE CWA ON SUNDAY
WITH MOST GUIDANCE SPEEDING UP THIS SYSTEM. THIS SYSTEM WILL NEED
TO CONTINUE BE MONITORED...DUE TO THE OVERALL STRENGTH OF THE
CONVECTIVE POTENTIAL STILL UNKNOWN AS WELL AS CHANCES FOR SOME
DECENT RAINFALL.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* 30-35 KT SOUTHWESTERLY FLOW AT 1000-1500 FT THROUGH 13Z.
* SMALL CHANCE FOR ISOLATED SHRA THIS AFTERNOON AND EVENING.
//DISCUSSION...UPDATED 06Z...
THE TERMINALS TODAY WILL REMAIN BETWEEN HIGH PRESSURE CENTERED
ACROSS THE NORTHEAST AND A WEAKENING LOW PRESSURE TROUGH MOVING
FROM MN TO THE UPPER GREAT LAKES. WARM AIR ADVECTION THROUGH THE
MORNING WILL KEEP MID-LEVEL CLOUD COVER DEVELOPING...AS WELL AS
SOME STIFF SSW WINDS NOT FAR OFF THE DECK /1000-1500 FT/. AN
AMDAR FLIGHT FROM RFD INDICATED 31 KT AT 1500 FT AND THESE WINDS
ARE LIKELY TO COME UP SOME BEFORE DAYBREAK AS WELL AS EXPAND
EASTWARD. AS THE WEAK SURFACE TROUGH MOVES EASTWARD AND BEGINS TO
WASH OUT...THERE WILL BE SOME WEAK INSTABILITY POOLING AHEAD OF
THIS ACROSS EASTERN IL/NW IN. ALSO...UPPER LEVEL DISTURBANCES
ALBEIT WEAK MOVING OVER THE AREA MAY JUST BE ENOUGH TO RENDER A
COUPLE STRAY SHOWERS. SOUTH WINDS WILL SEE SOME GUSTINESS
TODAY...MAINLY IN THE 15 TO 20 KT RANGE. SOUTHERLY WINDS WILL
CONTINUE ON SATURDAY WITH NO PRECIPITATION EXPECTED.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN 30-35 KT SOUTHWESTERLY FLOW AT 1000-1500 FT
THROUGH 13Z WITH MEDIUM CONFIDENCE IN THIS STAYING UNDER TRUE
LLWS.
* LOW CONFIDENCE IN THE DEVELOPMENT OF ANY AFTERNOON SHRA BUT HIGH
CONFIDENCE IF ANY WERE TO DEVELOP THEY WOULD BE ISOLATED.
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR. WX NIL.
SUNDAY...CHANCE TSRA. OTHERWISE...VFR.
MONDAY...CHANCE TSRA EARLY. OTHERWISE...VFR.
TUESDAY...VFR. WX NIL.
WEDNESDAY...VFR. WX NIL.
MTF/KJB
&&
.MARINE...
229 PM CDT
A TROUGH OF LOW PRESSURE STRETCHING FROM SASKATCHEWAN TO THE
SOUTHERN HIGH PLAINS WILL REMAIN NEARLY STATIONARY THROUGH FRIDAY
NIGHT...WHILE A DEEP AREA OF LOW PRESSURE DEVELOPS WITHIN THE
NORTHERN PERIPHERY OF THIS TROUGH OVER SASKATCHEWAN. THIS LOW WILL
MOVE NORTHEAST ACROSS MANITOBA SATURDAY AND SATURDAY NIGHT...AND
OVER HUDSON BAY SUNDAY AND SUNDAY NIGHT. THIS WILL SET UP A
PROLONGED PERIOD OF SOUTH WINDS ACROSS LAKE MICHIGAN THROUGH THE
WEEKEND. WARM AIR SPREADING ACROSS THE LAKE ON THESE SOUTH WINDS
WILL TEND TO LIMIT THE DEPTH OF THE MIXED LAYER OVER THE WATER...
WITH MODEL FORECAST SOUNDINGS DEPICTING 15-20 KTS AND SOME GUSTS
INTO THE 20-25 KT RANGE PARTICULARLY OVER THE NORTHERN AND NORTH
CENTRAL PARTS OF THE LAKE. SOME GUIDANCE DEPICTS A WEAKER SURFACE
WAVE DEVELOPING ACROSS THE MIDWEST BY EARLY SUNDAY...ALONG THE COLD
FRONT TRAILING THE DEEPER CANADIAN LOW. SOUTH-SOUTHEAST WINDS MAY
BRIEFLY PICK UP NEAR 20 KTS ON THE SOUTHERN PORTION OF THE LAKE
AHEAD OF THIS WAVE EARLY SUNDAY. THE COLD FRONT WILL THEN TRANSLATE
EAST ACROSS LAKE MICHIGAN SUNDAY NIGHT...WITH THE GRADIENT WEAKENING
IN THE VICINITY OF THE FRONTAL TROUGH WITH WINDS SHIFTING TO THE
NORTH-NORTHWEST. WEAK HIGH PRESSURE WILL THEN SPREAD ACROSS THE
UPPER MIDWEST BEHIND THE FRONT SUNDAY NIGHT AND MONDAY...MOVING
ACROSS THE WESTERN AND NORTHERN LAKES MONDAY NIGHT AND TUESDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
525 AM EDT FRI AUG 24 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EDT FRI AUG 24 2012
00Z RAOBS AND RUC ANALYSIS INDICATES ZONAL FLOW ALOFT DOWNSTREAM OF
SHARP TROUGH OVER WESTERN CANADA AND ON PERIPHERY OF BROAD RIDGE
OVER CENTRAL CONUS. AT THE SFC...DISJOINTED COMPLEX OF TROUGHS ARE
PRESENT FROM SAKSATCHEWAN INTO NORTH DAKOTA.
HAVE A DOWNRIGHT MESS OF CONVECTION OVER UPR LAKES THIS MORNING
AHEAD OF PAIR OF STRONGER SHORTWAVE TROUGHS MOVING INTO NORTHWEST
ONTARIO AND INTO SOUTHWEST WISCONSIN. H85 WARM ADVECTION IS
SUPPORTING MORE WEST-TO-EAST ORIENTED SHRA/TSRA OVR LK SUPERIOR
WHILE HEIGHT FALLS AND H85-H7 MOISTURE ADVECTION ALONG 2-5KM MUCAPE
RIBBON AND ALONG WEST EDGE OF H85 JET IS SPURRING ON MULTIPLE
CLUSTERS OF MODERATE-HEAVY SHRA/TSRA FROM SOUTHWEST LK SUPERIOR INTO
NORTHWEST WI AND INTO SOUTHWEST WI. ACTIVITY OVR SOUTHWEST WI IS
MORE ORGANIZED WITH SHARPER HEIGHT FALLS OVR THAT AREA DUE TO
SHORTWAVE. ENTIRE AREA IS WITHIN INFLUENCE OF BROAD DIVERGENCE
ALOFT AS H3 JET STREAK SURGES IN FROM THE NORTHERN PLAINS.
CURRENT RADAR TRENDS AND EXPECTED POSITION OF LOW-LEVEL JET THROUGH
MID MORNING SUGGESTS THAT SHRA/TSRA OVER WESTERN LK SUPERIOR WILL
LIFT ACROSS KEWEENAW AND REST OF LK SUPERIOR THIS MORNING. IT APPEARS
THAT CONVECTION OVER SOUTHWEST WISCONSIN WILL NOT MAKE MUCH PUSH
INTO UPR MICHIGAN AS PRIMARY SHORTWAVE STAYS MAINLY OVR WISCONSIN.
LOOKS LIKE MAIN EFFECT OF BOTH AREAS OF CONVECTION WILL BE TO KEEP
SCT-BKN MID CLOUDS IN OVER MOST CWA THIS MORNING...BUT DO EXPECT
SOME HEATING. BETTER HEATING OCCURS EARLY TO MID AFTN AND COULD TIME
OUT WELL WITH ARRIVAL OF SURGE OF H85-H7 MOISTURE FROM THE SOUTHWEST.
THERE IS CURRENTLY A VERY SHARP EDGE TO THE H7 MOISTURE AS SEEN WITH
ABRUPT CLEARING SEEN OVER SOUTHERN MINNESOTA. SREF /WHICH HAS OKAY
HANDLE ON CURRENT CONVECTIVE TRENDS/ BLASTS THIS DRY MID-LEVEL AIR
INTO WEST THIRD BY EARLY AFTN WITH MOISTURE GRADIENT SETTING UP OVR
CENTRAL CWA. DEPENDING ON EXTENT OF HEATING...INSTABILITY COULD
INCREASE WITH ML BASED CAPES OVR 1000 J/KG IN THE CNTRL CWA 18Z-22Z.
TRIGGER WOULD BE SHORTWAVE TROUGH AND SFC-H85 THETA-E ADVECTION AND
MAYBE DEVELOPING LK BREEZES /THOUGH WITH FAIRLY STRONG 950MB INTO
AFTN NOT AS CONFIDENT IN THIS POSSIBLE TRIGGER/. DEEP LAYER SHEAR
ENDS UP AROUND 30 KTS DURING THE AFTN...SO AT LEAST BRIEF
ORGANIZATION/STRONG STORMS SEEMS POSSIBLE GIVEN THE INSTABILITY.
OVERALL...THINK SETUP CONTINUES TO JUSTIFY GOING FCST OF SCT POPS
MAINLY IN THE AFTN...HIGHEST OVER CENTRAL CWA. CONTINUED TO TRIM
POPS OVER WEST...JUST TOO MUCH DRYING TO TRIGGER ANY ADDITIONAL
CONVECTION THERE. BASED ON CURRENT RADAR/SATELLITE TRENDS...THINK
CLEARING IS LIKELY OVR MOST OF CWA THROUGH THE MORNING. SO...WARMER
TEMPS AS NAM INDICATES ARE PREFERRED. BASED ON MIXING TO H85 TEMPS
NEAR +19C...MAX TEMPS MAY TOP OUT WELL INTO THE UPPER 80S. WARM
START TO THE DAY WILL NOT HINDER THIS PROCESS EITHER.
SHORTWAVE TROUGH/MOISTURE ADVECTION CRUISES EAST EARLY THIS EVENING
AND OTHER THAN SOME SMALL CHANCES HAVE PRETTY MUCH ENDED POPS BTWN
00Z-06Z FOR ALL BUT EAST AND SOUTH FRINGES OF CWA. NAM IS QUITE
BULLISH ON POPS FOR OVERNIGHT TONIGHT...MUCH MORE SO THAN OTHER
MODELS. LOOKING AT SOUNDINGS...MOISTURE IS BACK ON THE INCREASE
ALOFT /ROUGHLY ABOVE H7/. LAPSE RATES KIND OF STEEP H7-H5...TOWARD
7C/KM. A LOT OF DRY AIR BLO H7 AND STRONG LIFT LOOKS TO BE LACKING.
MAY SEE A WEAK SHORTWAVE STREAKING OUT AHEAD OF DEEPER WESTERN
CANADA TROUGH WHICH COULD ENHANCE LIFT. KEPT ISOLD MENTION FOR
SHRA/TSRA OVER NORTH TWO-THIRDS OF CWA OUT INTO LK SUPERIOR ALONG
AND NORTH OF H85 FRONT...BUT EVEN THIS POSSIBILITY WILL DIMINISH
LATE IN THE NIGHT AS H7 MOISTURE TRANSPORT WEAKENS AS DOES UVM IN
THE H7-H5 LAYER. SHOULD BE ANOTHER WARM NIGHT /READINGS IN THE 60S/
DUE TO PERSISTENT SOUTH WINDS OUT AHEAD OF SFC LOW DEEPENING OVR
CANADIAN PRAIRIES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 523 AM EDT FRI AUG 24 2012
SATURDAY...AS THE MID LEVEL LOW OVER SASK LIFTS INTO NORTHERN
MANITOBA RIDGING WILL PREVAIL DOWNSTREAM OVER THE GREAT LAKES. AS A
RESULT...DRY MID LEVELS AND CAPPNIG SHOULD LIMIT ANY PCPN
CHANCES...PER ECMWF/GFS. HOWEVER...SINCE THE REGIONAL GEM AND NAM
CONTINUE TO SUGGEST THAT A WEAK SHORTWAVE TROUGH LIFTING OUT OF THE
UPPER MS VALLEY COULD BRING SOME PCPN INTO THE WEST...SLIGHT CHANCE
WAS MENTIONED IN THE LATE AFTERNOON. WITH PLENTY OF SUNSHINE/MIXING
AND 850 MB TEMPS INTO THE 18C-20C RANGE...EXPECT MAX READINGS INTO
THE UPPER 80S WITH A FEW 90S POSSIBLE IN SW FLOW DOWNSLOPE LOCATIONS.
SATURDAY NIGHT AND SUNDAY...THE MODELS SUGGEST THAT THE STRONGER
FORCING AND HEIGHT FALLS AHEAD OF THE MID LEVEL LOW WILL REMAIN
NORTH OF UPPER MICHIGAN WHILE A WEAKER SHORTWAVE MOVING OUT OF THE
CNTRL PLAINS AND GREATER INSTABILITY WILL REMAIN TO THE SOUTH.
SO...THE DRIER QPF FROM THE ECMWF/GEM SCENARIO WAS PREFERRED
COMPARED TO THE GFS. NEVERTHELESS...SCT SHRA/TSRA ARE STILL EXPECTED
AS THE SFC TROUGH AND AXIS OF HIGHER MOISTURE MOVE THROUGH THE CWA.
ANY LINGERING PCPN SHOULD EXIT THE CNTRL CWA SUN EVENING AND THE
EAST OVERNIGHT.
MON-THU...THE MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD
PATTERN AMPLIFICATION AS A TROUGH MOVES INTO THE WRN CONUS AND RIDGE
DEVELOPS FROM THE CNTRL ROCIES INTO THE PLAINS. THE NW FLOW PATTERN
INTO THE UPPER GREAT LAKES WILL BRING A SFC HIGH AND COOLER DRIER
AIR INTO UPPER MI MON-TUE WHICH WOULD GIVE WAY TO WARMING BY
WED-THU. CONFIDENCE IN PCPN POTENTIAL BY WED-THU WITH POTENTIAL
FRONTAL SYSTEM AND HEIGHT FALLS IS LOW GIVEN INCREASING MODEL SPREAD
AND RUN TO RUN VARIATION WITH THE STRENGTH OF THE RIDGE. SO
CONSENSUS SLIGHT CHANCE POPS WERE NOT ALTERED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 140 AM EDT FRI AUG 24 2012
VFR CONDITIONS ARE EXPECTED AT ALL SITES THROUGHOUT THE PERIOD. MORE
SHOWERS AND THUNDERSTORMS WILL MOVE BACK IN OVERNIGHT OVER KIWD AND
KCMX AND PUT SOME THUNDER INTO THE KCMX AND KIWD EARLY THIS TAF
PERIOD AS THERE ARE THUNDERSTORMS HEADED TOWARDS THAT AREA FROM NW
WISCONSIN. THIS IS ALSO WHERE MOST UNSTABLE AIR WILL BE AND BEST PCPN
CHANCES. FOR KSAW...KEPT SHOWERS MOSTLY WEST AND PUT IN PROB30 GROUP
WHEN TROUGH PASSES IN THE AFTERNOON. A LOW-LEVEL JET WILL CREATE WEAK
LLWS AT ALL SITES OVERNIGHT. PCPN SHOULD BE OUT OF THE AREA BY
MORNING AT ALL SITES EXCEPT FOR SAW WHERE IT WILL LINGER INTO THE MID
AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 523 AM EDT FRI AUG 24 2012
SOUTH TO SOUTHEAST WINDS REMAIN STRONG TODAY ESPECIALLY OVER EASTERN
SECTIONS WHERE GUSTS MAY REACH 25-30 KTS AT HIGHER PLATFORMS AND
SHIP LEVEL. LOW-LEVEL JET AXIS FADES AWAY TONIGHT...SO WINDS SHOULD
DECREASE TO LESS THAN 20 KTS. WINDS EXPECTED TO REMAIN AT 20 KTS OR
LESS THROUGH THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK AS
STRONGEST PRESSURE GRADIENT STAYS WELL TO NORTH IN THE VICINITY OF
STRONG SFC LOW OVER HUDSON BAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
349 AM CDT FRI AUG 24 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CONCERNS THROUGH THE FIRST FEW DAYS OF THE FORECAST DEAL
WITH TEMPERATURES...CLOUD COVER...AND RAIN CHANCES THROUGH
SATURDAY.
ONGOING STORM COMPLEX BRINGING MUCH NEEDED RAINFALL ACROSS KANSAS
THIS MORNING...SPC MESOANALYSIS SHOWED STRONG MOISTURE ADVECTION
INTO THE STORMS...WHICH WAS ECHOED BY PROFILER DATA WITH 850MB
WINDS OF 35 TO 45KTS INTO THE SYSTEM. ANALYSIS ALSO SHOWED A
STRONG PRECIPITABLE WATER GRADIENT WITH 1.50 TO 2.00 INCHES ACROSS
KANSAS INTO EASTERN NEBRASKA...WHILE THE NORTHERN NEBRASKA
PANHANDLE WAS OBSERVING VALUES LESS THAN THREE QUARTERS OF AN
INCH. ALTHOUGH GOOD RAINFALL WAS OCCURRING OVER KANSAS...THE LOCAL
AREA STAYED DRY OVERNIGHT. THE AREA DID SEE SOME RAIN
YESTERDAY...HOWEVER AMOUNTS WERE LIGHT WITH KLBF BEING THE
WINNER OF THE DAY WITH 0.13 INCHES. THERE IS LIKELY A FEW
LOCATIONS OVER FRONTIER COUNTY THAT MAY HAVE GOTTEN A BIT MORE
RAINFALL DUE TO SOME LATE EVENING THUNDERSTORMS...HOWEVER NO
REPORTED AMOUNTS HAVE BEEN RECEIVED YET.
LOOKING AT WATER VAPOR IMAGERY...A STRONG UPPER LEVEL LOW WAS
SITUATED OVER THE FOUR CORNERS WITH A GOOD FLUX OF MOISTURE
STREAMING NORTHWARD AHEAD OF THIS SYSTEM. THIS HAS BEEN SEEN IN
THE INCREASE OF PRECIPITABLE WATER VALUES AS WAS MENTIONED ABOVE.
ALSO OF NOTE IN THE LARGE SCALE IS A SHORTWAVE TROUGH OVER THE
PACIFIC NORTHWEST...AS WELL AS TROPICAL STORM ISAAC IN THE
CARIBBEAN. CLOSER TO HOME...LOW PRESSURE WAS ANALYZED OVER
SOUTHEAST COLORADO...WITH A SECOND LOW CENTERED OVER EASTERN
MONTANA. SOUTHERLY WINDS WERE BRINGING MOISTURE IN FROM THE
SOUTH...HOWEVER A TIGHT MOISTURE GRADIENT EXISTED WITH DEWPOINTS
RANGING FROM THE 30S IN SOUTHWEST SOUTH DAKOTA TO THE MID AND UPPER
60S FROM SOUTHWEST INTO CENTRAL NEBRASKA.
FOR TODAY...CLOUD COVER WILL HAVE A LARGE IMPACT ON TEMPERATURES.
THERE IS CONSIDERABLE DIFFERENCES IN THE LOW LEVEL MOISTURE FIELDS
FOR THIS MORNING...WITH THE NAM BEING QUITE A BIT DRIER THAN THE
RAP/GFS SOLUTIONS. THE 11-3.9 IR AT 08Z WAS SHOWING THE
FOG/STRATUS EXPANDING QUITE A BIT SO WILL EDGE ON A MORE CLOUDY
FORECAST FOR TODAY. WITH THE MODELS NOT HANDLING THIS WELL HAVE
LOW CONFIDENCE ON HOW FAST THIS MOISTURE WILL SCOUR OUT TODAY.
EARLIER RAP RUNS HAD KEPT THE LOW CLOUDS IN THROUGH MUCH OF THE
DAY...HOWEVER LATEST /24.06Z RUN/ STARTS TO BREAK THINGS OUT
AROUND 18Z. NAM WOULD ALSO HAVE CLOUDS OUT BY 18Z. WITH NO REAL
FOCUS FOR MOISTURE CONVERGENCE THROUGH THE DAY BELIEVE THE LOW CLOUDS
WILL EVENTUALLY DISSIPATE. MAY START TO SEE SOME MID/HIGH LEVEL
CLOUDS MOVING IN THOUGH AT THIS POINT AS BOTH THE UPPER LOW OVER
THE FOUR CORNERS AND THE PACIFIC NORTHWEST SYSTEM MOVE EAST. SO AS
TEMPERATURES SHOULD START TO RECOVER /WITH GOOD WARMING POTENTIAL
IF SEVERAL HOURS OF SUNSHINE ARE REALIZED/ STILL WENT CONSERVATIVE
WITH HIGHS TODAY AND KEPT SOUTHERN AREAS IN THE MID 80S.
SOME MODELS WOULD SUGGEST PRECIPITATION THIS MORNING AND EARLY
AFTERNOON...BUT FROM THE LOOKS OF MOISTURE TRANSPORT
VECTORS...PRECIPITATION SHOULD BE PUSHED TO THE EAST SO KEPT THE
FORECAST THROUGH MID AFTERNOON DRY. BY 25.00Z THE SOUTHERN UPPER
LEVEL SYSTEM WILL BE OVER EASTERN COLORADO...WITH A SURFACE LOW
REMAINING JUST TO ITS EAST. THE LOW LEVEL JET DOES STRENGTHEN
CONSIDERABLY INTO THE EVENING AND OVERNIGHT HOURS...HOWEVER MOST
OF THIS MOISTURE/CONVERGENCE/ENERGY STAYS INTO CENTRAL AND EASTERN
KANSAS AND EASTERN NEBRASKA SO LIMITED RAIN CHANCES TO THE FAR
EASTERN COUNTIES IN THE FORECAST AREA. THIS WAS SUPPORTED BY THE
23.21Z AND 24.03Z SREF RUNS WHICH DID NOT HAVE ANY PROBABILITIES
OF RAINFALL AMOUNTS OVER 0.25 INCH IN THE LOCAL FORECAST AREA.
CONCERNING THE NORTHERN SYSTEM...THE SHORTWAVE WILL BE OVER
SOUTHERN SASKATCHEWAN AT 25.00Z. THIS WILL BRING THE COLD FRONT
INTO THE WESTERN DAKOTAS AND THE NEBRASKA PANHANDLE. KEPT THE
FORECAST DRY OVERNIGHT AS THE FRONT PUSHES EAST...WITH THE
STRONGEST FORCING STAYING WELL TO THE NORTH. THERE IS INDICATIONS
OF SOME MOISTURE CONVERGENCE ALONG THE FRONT OVERNIGHT...SO
WOULDN/T BE SURPRISED TO SEE AN ISOLATED STORM DEVELOP...BUT AGAIN
DIDN/T HAVE THE CONFIDENCE TO ADD CHANCES IN AT THIS POINT.
THE FRONT PUSHES THROUGH THE FORECAST AREA ON SATURDAY...BRINGING
DRIER AND COOLER AIR BEHIND IT. CONVECTION SHOULD CONTINUE
THROUGH THE DAY ALONG THE FRONT. WITH MODELS BEING IN GOOD
AGREEMENT WITH PUSHING THE RAIN EAST OF THE FORECAST AREA...DID
TREND THE FORECAST THAT DIRECTION. DID LEAVE IN SOME SLIGHT
CHANCES IN THE NORTHEASTERN ZONES TO ACCOUNT FOR SLOWER FRONTAL
MOVEMENT OR LINGERING ACTIVITY. DID KEEP TEMPERATURES AHEAD OF THE
FRONT LOWER AS THE FRONT WILL PUSH THROUGH BEFORE AFTERNOON
HEATING SETS IN...AS WELL AS THE THOUGHT THAT THERE MAY AGAIN BE A
BATCH OF STRATUS IN THESE AREAS IN THE MORNING. ALTHOUGH
TEMPERATURES WILL BE COOLER ON SATURDAY...WITH HIGHS IN THE
80S...DEWPOINTS LOOK TO DROP INTO THE 30S BEHIND THE FRONT. THIS
WILL DROP RELATIVE HUMIDITY TO AROUND 20 PERCENT IN THE AFTERNOON.
ALSO EXPECTING BREEZY NORTHERLY WINDS BEHIND THE FRONT. ALTHOUGH
DON/T ANTICIPATE NEEDING HEADLINES FOR FIRE WEATHER...WILL NEED TO
KEEP THIS IN MIND AS FIRE WEATHER CONDITIONS WILL BE NEAR
CRITICAL.
SATURDAY NIGHT THROUGH SUNDAY NIGHT SHOULD BE FAIRLY QUIET AS
UPPER LEVEL RIDGING STARTS TO BUILD IN AS THE SHORTWAVES EXIT TO
THE EAST. SKIES SHOULD CLEAR THROUGH THE PERIOD WITH HIGH PRESSURE
SETTLING IN. COULD SEE TEMPERATURES DROP DOWN INTO THE 50S OVER
MUCH OF THE AREA SATURDAY NIGHT...DUE TO GOOD RADIATIONAL COOLING.
.LONG TERM...MONDAY THROUGH THURSDAY
NO BIG CONCERNS TO DEAL WITH THROUGH THIS PORTION OF THE FORECAST.
THE UPPER LEVEL RIDGE BUILDS IN...SO ANOTHER WARMING TREND IS
EXPECTED WITH HIGHS IN THE UPPER 80S AND 90S THROUGH MUCH OF THE
WEEK. NO GOOD CHANCES FOR RAIN EXIST...ALTHOUGH THERE MAY BE
STORMS TOPPING THE RIDGE TO IMPACT NORTHERN NEBRASKA. WITH VERY
LITTLE CONFIDENCE ON WHEN AND WHERE THESE STORMS WILL DEVELOP KEPT
THE FORECAST DRY THROUGHOUT THIS TIME. WITH THE DRY
CONDITIONS...AND WITH A LACK OF MOISTURE BEING BROUGHT
NORTH...WILL EXPECT LARGE TEMPERATURE SWINGS SO ALTHOUGH HIGHS
WILL BE IN THE 90S...STILL LOOKING AT LOWS IN THE 50S AND LOW 60S
MOST NIGHTS.
EYES CONTINUE TO WATCH TROPICAL STORM ISAAC...WHICH IS WELL OUT IN
THE CARIBBEAN CURRENTLY. LONG TERM MODELS COMING INTO MORE
AGREEMENT IN SOLUTIONS...BRINGING IT ONSHORE NEAR MOBILE ALABAMA
THEN PUSHING NORTHWARD INTO THE OHIO RIVER VALLEY BEFORE BEING
CAUGHT UP IN THE FLOW AND SHUNTED EAST. THIS WOULD PROVIDE NO HELP
TO THE LOCAL AREA IN TERMS OF MOISTURE UNFORTUNATELY. THIS IS ALL
TO OCCUR NEXT WEEKEND AND THE NEXT WEEK SO THINGS COULD CERTAINLY
CHANGE BEFORE THEN AND WILL BE WATCHING TO SEE IF THERE MAY BE ANY
IMPACT LOCALLY FROM THIS STORM.
&&
.AVIATION...
FOR THE KLBF AND KVTN TERMINALS THROUGH 12Z SATURDAY.
FOR THE KLBF TERMINAL...ABUNDANT LOW LEVEL MOISTURE IS EXPECTED OVER
THE NEXT 24 HOURS...WHICH WILL LEAD TO IFR CIGS THROUGH LATE MORNING
ACROSS SOUTHWESTERN NEBRASKA. PERIODIC MVFR CIGS ARE EXPECTED
THROUGH EARLY AFTERNOON WITH VFR CIGS EXPECTED THROUGH MID EVENING.
WITH COOLING TEMPS AFTER SUNDOWN...LOW LEVEL CLOUDINESS WILL BEGIN
TO WORK BACK INTO SOUTHWESTERN NEBRASKA AFTER 06Z TONIGHT. BASED ON
THE LATEST SREF PROBABILITIES...NOT CONFIDENT ENOUGH YET TO PUT IFR
CIGS IN THE LAST 6 HRS OF THE FCST AND WILL OPT FOR MVFR CIGS ATTM.
AS FOR PRECIPITATION...COVERAGE IS EXPECTED TO BE SCATTERED SOUTH
AND EAST OF THE KLBF TERMINAL...WITH ISOLATED COVERAGE FCST IN THE
KLBF VICINITY. WITH THIS IN MIND...WILL FORGO MENTION OF TSRAS IN
THE 12Z KLBF TAF. WINDS OVER THE NEXT 24 HRS...WILL BE FROM THE
SOUTHEAST OR EAST SOUTHEAST AT UNDER 10 KTS.
FOR THE KVTN TERMINAL...LOW CLOUDINESS IS EXPECTED TO REMAIN SOUTH
OF THE KVTN TERMINAL THIS MORNING. EXPECT SOME SCATTERED TO BROKEN
MID LEVEL CLOUDINESS TO DEVELOP LATER THIS AFTERNOON WITH CIGS
RANGING FROM 7000 TO 9000 FT AGL. WINDS WILL BE FROM THE SOUTH AT 10
KTS THIS MORNING...INCREASING TO 10 TO 20 KTS THIS
AFTERNOON...BEFORE DIMINISHING TO AROUND 10 KTS TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT/LONG TERM...BROOKS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
300 AM MDT FRI AUG 24 2012
.DISCUSSION...
UPPER LOW CIRCULATION NEAR KFMN EARLY THIS MORNING. RUC OPENS IT UP
BY MIDDAY WHILE FORECAST POSITION WILL BE OVER NRN MTS. GFS SEEMS TO
MOVE THE TROUGH A LITTLE FASTER THAN 24 HOURS AGO WHILE NAM
INDICATES SOME HANG BACK ENERGY WHICH RETARDS EASTWARD PROGRESS AND
THEREFORE THE TROUGHS EXIT UNTIL LATE SATURDAY AFTERNOON.
NONETHELESS...MOISTURE WILL REMAIN IN PLACE TODAY AND TONIGHT
ESPECIALLY AOB H5 WHILE MODELS AND SATELLITE IMAGERY INDICATE DRYING
IN THE UPPER LEVELS OF THE ATMOSPHERE. UPSLOPE WINDS SHOULD FAVOR
CONVECTION OVER THE WESTERN/NORTHERN MOUNTAINS TODAY AND WITH WIND
SHIFT IN THE NORTHEAST...THE FOCUS FOR RAIN MAY LIKELY SHIFT INTO
THAT REGION LATER THIS AFTERNOON/EVENING WITH THE UPPER TROUGH
NEARING. TEMPERATURES TODAY STILL A BIT ON THE LOWER SIDE OF AVERAGE
CENTRAL AND WEST...BUT A LITTLE ABOVE IN THE EAST.
SATURDAY WILL BE A TRANSITION DAY AS THE TROUGH EXITS AND AN
EASTERLY LOW LEVEL GRADIENT SETS UP OVER EASTERN NEW MEXICO. THERE
MAY BE SOME POTENTIAL FOR AN EAST WIND INTO THE RGV SATURDAY
NIGHT...BUT THIS APPEARS MORE LIKELY SUNDAY/SUNDAY NIGHT AS THE
UPPER HIGH CENTER SETS UP SHOP OVER NRN NM/SRN CO. WHILE LOW LEVEL
MOISTURE MAY START TO DRY/MIX OUT IN THE FAR NORTHWEST...THE
BOUNDARY LAYER WINDS SHOULD KEEP DEWPOINTS FROM CRATERING IN THE
EAST. TEMPERATURE WISE...MOST AREAS SHOULD BE A FEW DEGREES WARMER
THAN AVERAGE DURING THE DAY BY MONDAY...WHILE MINS GENERALLY STAY
ABOVE NORMAL FOR THE NEXT SEVERAL DAYS.
BY MID TO LATE NEXT WEEK...FORECAST MODELS CONTINUE TO HAVE TROUBLE
RESOLVING THE STRENGTH OF THE UPPER HIGH AND THE LOCATION AND
STRENGTH OF THE WESTERLIES OVER THE NORTHERN/CENTRAL TIER OF THE
WESTERN U.S. CONFIDENCE NOT ALL THAT GREAT IN ONE SCENARIO VS
ANOTHER SO GENERIC AFTERNOON/EVENING SHOWERS AND STORMS FAVORING THE
HIGHER TERRAIN SEEMS BEST FOR NOW.
&&
.FIRE WEATHER...
WEAK UPPER LEVEL DISTURBANCE IS CURRENTLY CENTERED NEAR THE FOUR
CORNERS WITH MID AND UPPER LEVEL DRY SLOT WORKING INTO CENTRAL NEW
MEXICO. SURFACE DEWPOINTS DECREASING AS WELL ESPECIALLY WEST AND
CENTRAL ZONES. THE UPPER WAVE WILL MOVE TO THE EAST DURING THE DAY
WITH WETTING RAIN FAVORING THE WESTERN AND NORTHERN ZONES WITH
BREEZY WEST WINDS DEVELOPING THIS AFTERNOON ACROSS THE EAST CENTRAL
PLAINS. TEMPS WARM A BIT MOST ZONES WITH SUBSTANTIAL DECREASES IN
AFTERNOON RH VALUES.
HIGH PRESSURE BUILDS IN THE WAKE OF THE UPPER LEVEL DISTURBANCE WITH
A RIDGE AXIS NEAR THE FOUR CORNERS BY MID DAY SATURDAY SUPPORTING
ADDITIONAL WARMING AND DRYING ACROSS WESTERN AND NORTHCENTRAL ZONES.
SUFFICIENT MOISTURE PERSISTS AT THE SURFACE TO SUPPORT SCATTERED
THUNDERSTORMS OVER THE HIGHER TERRAIN WITH ISOLATED COVERAGE
ELSEWHERE. A BACK DOOR FRONT WILL PUSH INTO THE NORTHEAST LATE ON
SATURDAY AND THROUGH THE EAST PLAINS ON SUNDAY AS THE UPPER HIGH
CENTERS OVER NEW MEXICO. MODERATE GAP WINDS WERE ADDED TO THE GRIDS
FOR SATURDAY NIGHT...AND DEPENDING ON THE STRENGTH OF THE EAST WINDS
SURFACE MOISTURE INCREASES COULD MAKE IT TO THE CONTINENTAL DIVIDE.
WETTING RAINS ON SUNDAY LOOK TO FAVOR THE CENTRAL HIGH TERRAIN AND
ADJACENT EAST SLOPES WITH AN UPTICK IN COVERAGE OVER THE WESTERN
TERRAIN.
MODELS GENERALLY AGREE ON BUILDING THE UPPER HIGH EARLY IN THE WORK
WEEK WITH POSSIBLY A SLIGHT SHIFT TO THE EAST. A MONSOON PLUME WORKS
AROUND THE WESTERN EDGE OF THE HIGH...BUT THE FOCUS REMAINS OVER
MEXICO. THE EASTERN PLAINS LOOK TO BE DRIER WITH PRECIPITATION
SHIFTING TO THE WEST. THE RIDGE LOOKS TO WEAKER LATER IN THE WEEK
WITH A GENERAL DECREASE IN RELATIVE HUMIDITIES AND WETTING RAIN MOST
LOCATIONS.
&&
.AVIATION...
06Z TAF CYCLE
NOT CARRYING ANY SHOWER AT TERMINALS OVERNIGHT. MIGHT BE A CLOSE
CALL AT SAF AROUND 7Z. GENERALLY VFR CONDITIONS THROUGH 18Z FRIDAY.
COULD GET LOCALIZED FOG/BR WITH LOWER CIGS DUE TO PREVIOUS RAINFALL
10Z TO 14Z AT SOME TERMINALS...NAMELY FMN...GUP...TCC AND ROW...
ALTHOUGH MODELS AND GUIDANCE NOT SHOWING MUCH. SHOWERS AND STORMS TO
REFORM FRIDAY...MOSTLY AFTER 18Z AND NORTH OF INTERSTATE 40. WILL
CARRY VCSH AND/OR VCTS AT FMN...GUP...SAF AND LVS FRIDAY AFTERNOON.
CHJ
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 82 57 89 60 / 30 30 20 20
DULCE........................... 76 51 82 49 / 40 40 20 20
CUBA............................ 74 52 79 52 / 30 30 20 20
GALLUP.......................... 77 52 84 56 / 30 30 20 20
EL MORRO........................ 72 50 79 52 / 30 30 20 20
GRANTS.......................... 76 52 84 54 / 30 30 20 20
QUEMADO......................... 76 52 82 55 / 30 30 20 20
GLENWOOD........................ 83 60 86 58 / 20 20 20 20
CHAMA........................... 70 45 75 47 / 40 50 30 20
LOS ALAMOS...................... 77 54 81 58 / 40 30 20 30
PECOS........................... 77 54 78 55 / 30 30 40 30
CERRO/QUESTA.................... 74 47 76 49 / 40 40 20 30
RED RIVER....................... 66 45 70 44 / 50 50 30 40
ANGEL FIRE...................... 69 46 72 42 / 40 50 40 40
TAOS............................ 78 50 80 52 / 30 40 20 30
MORA............................ 75 51 76 52 / 30 30 40 30
ESPANOLA........................ 82 56 86 57 / 20 30 20 30
SANTA FE........................ 79 55 84 58 / 30 30 30 30
SANTA FE AIRPORT................ 81 56 86 59 / 30 30 20 30
ALBUQUERQUE FOOTHILLS........... 83 61 84 63 / 20 20 20 20
ALBUQUERQUE HEIGHTS............. 83 64 87 66 / 20 20 20 30
ALBUQUERQUE VALLEY.............. 84 59 89 63 / 20 20 20 20
ALBUQUERQUE WEST MESA........... 84 59 88 63 / 20 20 20 30
LOS LUNAS....................... 86 62 88 63 / 20 20 20 20
RIO RANCHO...................... 83 62 87 65 / 20 20 20 30
SOCORRO......................... 86 65 88 65 / 20 20 20 20
SANDIA PARK/CEDAR CREST......... 80 58 78 56 / 20 20 40 30
TIJERAS......................... 82 61 82 59 / 20 30 30 30
MORIARTY/ESTANCIA............... 81 54 85 56 / 30 30 40 30
CLINES CORNERS.................. 80 56 81 57 / 30 20 40 30
GRAN QUIVIRA.................... 81 59 83 59 / 30 30 40 30
CARRIZOZO....................... 82 63 83 60 / 20 20 20 30
RUIDOSO......................... 76 60 75 54 / 30 30 40 40
CAPULIN......................... 78 49 81 56 / 40 40 30 40
RATON........................... 83 52 84 56 / 40 40 30 30
SPRINGER........................ 85 53 85 56 / 30 40 30 30
LAS VEGAS....................... 81 53 81 54 / 30 30 40 30
CLAYTON......................... 87 62 88 61 / 30 40 40 30
ROY............................. 85 60 85 60 / 30 30 40 40
CONCHAS......................... 92 62 91 65 / 20 30 20 20
SANTA ROSA...................... 90 62 89 65 / 20 20 20 20
TUCUMCARI....................... 94 63 91 66 / 20 30 20 20
CLOVIS.......................... 91 63 89 66 / 10 20 20 20
PORTALES........................ 92 64 89 67 / 10 20 20 20
FORT SUMNER..................... 92 65 91 66 / 10 20 20 20
ROSWELL......................... 95 68 93 69 / 10 20 20 20
PICACHO......................... 88 64 85 62 / 10 20 20 20
ELK............................. 83 63 79 59 / 20 20 40 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
1205 AM CDT FRI AUG 24 2012
.AVIATION... 24/06Z TAFS...VFR FORECAST WITH MVFR CONDITIONS IN/NEAR
THUNDERSTORMS. SOME MVFR STRATUS FORECAST BY A FEW MODELS ACROSS
CENTRAL AND SOUTHWEST OKLAHOMA...BUT CONFIDENCE NOT HIGH ENOUGH TO
MENTION. AREA OF RAIN WITH EMBEDDED THUNDERSTORMS EXPECTED TO MOVE
INTO NORTHWEST PORTIONS OF OKLAHOMA AFTER MIDNIGHT THEN PROGRESS
EASTWARD AND WEAKEN THROUGH THE EARLY MORNING HOURS. WILL KEEP TEMPO
MENTIONED MAINLY NORTHWEST AND NORTH-CENTRAL OKLAHOMA TERMINALS.
ADDITIONAL STORMS MAY DEVELOP LATE TOMORROW NEAR WESTERN OKLAHOMA
TERMINALS SO WILL INCLUDE PROB30 LATE IN FORECAST. WILL KEEP THE
/AMD NOT SKED/ AT KCSM WHERE FAA COMMS ISSUES CONTINUE.
&&
.PREV DISCUSSION... /ISSUED 1007 PM CDT THU AUG 23 2012/
.UPDATE...
A MINOR UPDATE HAS BEEN SENT TO ADJUST POPS A BIT THROUGH THIS
EVENING.
&&
.DISCUSSION...
TWO AREAS OF MOIST CONVECTION ARE PRESENT THIS EVENING OUTSIDE OF
OUR FA. THE FIRST...AND MORE ORGANIZED...IS LOCATED ACROSS NORTH
CENTRAL AND WEST CENTRAL KS. THE OTHER LOOSELY DEFINED AREA
EXTENDS FROM THE TX PANHANDLE SSWD THROUGH SE NM AND WEST
TX...AHEAD OF AN APPROACHING UPPER LOW CLEARLY SEEN PASSING OVER
THE FOUR CORNERS REGION. MOST OF THE MODELS GENERALLY HAVE SOME
CLUE WITH REGARDS TO THIS ACTIVITY...BUT PREVIOUS HRRR RUNS AND
ECMWF APPEAR TO HAVE THE BEST IDEA. THAT BEING SAID...A LLJ WILL
DEVELOP SIMILAR TO LAST NIGHT WEST OF I35. THE PREVIOUS MAY HELP
MAINTAIN/AMPLIFY THIS ACTIVITY AS IT APPROACHES BOTH FROM THE WEST
AND NORTH ESPECIALLY ACROSS WESTERN AND NORTHERN OKLAHOMA THROUGH
THE EARLY MORNING HOURS.
&&
.PREV DISCUSSION... /ISSUED 650 PM CDT THU AUG 23 2012/
AVIATION...
24/00Z TAFS...PRIMARILY VFR FORECAST WITH MVFR CONDITIONS IN/NEAR
THUNDERSTORMS. AREA OF RAIN WITH EMBEDDED THUNDERSTORMS PROGD BY
MOST MODELS TO MOVE INTO NORTHWEST PORTIONS OF OKLAHOMA TOWARD AND
AFTER MIDNIGHT THEN PROGRESS EASTWARD AND WEAKEN THROUGH TOMORROW
MORNING. LATEST HRRR AND RECENT RUNS OF OUNWRF SUPPORT THIS IDEA.
WILL KEEP TEMPO MENTIONED MAINLY AT NORTHERN AND FAR WESTERN
OKLAHOMA TERMINALS WHERE COVERAGE MAY BE A BIT HIGHER. WILL
INCLUDE /AMD NOT SKED/ AT KCSM WHERE FAA COMMS ISSUES CONTINUE.
PREV DISCUSSION... /ISSUED 336 PM CDT THU AUG 23 2012/
DISCUSSION...
SCATTERED LIGHT SHOWERS ASSOCIATED WITH MID-LEVEL
CLOUDS...CONTINUE TO DRIFT ACROSS OKLAHOMA AND THE TEXAS
PANHANDLE THIS AFTERNOON IN ADVANCE OF AN UPPER TROUGH.
THE UPPER TROUGH/LOW OVER SOUTHERN UTAH WILL NOT MOVE
ACROSS THE SOUTHERN PLAINS UNTIL SATURDAY/SUNDAY.
MEANWHILE...IT APPEARS BETTER CHANCES FOR SHOWERS/SOME STORMS
WILL BE ACROSS PARTS OF WESTERN AND NORTHERN OKLAHOMA NEAR A
STRONGER LOW LEVEL FLOW AND MID-LEVEL MOISTURE. IF A LARGE ENOUGH
AREA OF PRECIP CAN DEVELOP...BETTER CHANCES OF RAIN/STORMS MAY
MOVE INTO CENTRAL AND SOUTHERN OKLAHOMA TONIGHT INTO FRIDAY NIGHT.
MODELS AND HPC GUIDANCE CONTINUE TO SHOW THE POTENTIAL FOR 1 TO 3
INCH RAINFALL AMOUNTS THROUGH EARLY SUNDAY...MAINLY NORTHWEST OF
I-44.
AFTER SUNDAY/MONDAY...HEIGHT RISES ASSOCIATED WITH A
STRENGTHENING MID/UPPER LEVEL RIDGE WILL BRING DRY AND
HOTTER CONDITIONS TUESDAY INTO THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 91 69 86 72 / 20 20 40 60
HOBART OK 89 68 89 70 / 30 50 50 50
WICHITA FALLS TX 94 70 91 74 / 20 20 30 30
GAGE OK 89 68 90 69 / 30 60 50 60
PONCA CITY OK 92 69 85 71 / 20 40 50 60
DURANT OK 90 68 89 73 / 10 10 20 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
03/11
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
328 AM CDT FRI AUG 24 2012
.SHORT TERM...
RAIN CHANCES FOR MOST OF WEST CENTRAL TEXAS LOOK SOMEWHAT PROMISING
FOR THE NEXT 24 HOURS. MODELS INDICATE A SHORT WAVE TROUGH OF LOW
PRESSURE WILL PROVIDE SOME UPPER-LEVEL DYNAMICS. MODELS SHOW THIS
FEATURE BEST AT 700 MB. ALTHOUGH THE NAM AND THE RUC (HIGH
RESOLUTION RAPID REFRESH) INDICATE SOME DECLINE IN CONVECTIVE
COVERAGE BETWEEN NOW AND 18Z...I DECIDED TO INCLUDE THE FIRST 6
HOURS OF THE TODAY PERIOD WITH SLIGHT CHANCE TO CHANCE POPS ACROSS
THE BOARD. IN ADDITION...MODELS CONTINUE AT LEASE A SLIGHT CHANCE
THROUGH TONIGHT. ALSO...HPC QPF GRIDS FOR THE FIRST 24 HOURS LOOK
REASONABLE.
AS FOR TEMPERATURES...NUMBERS CLOSE TO MEX MOS LOOK ON TRACK FOR
TODAY AND TONIGHT. LIMITED SUNSHINE AND NORTHWEST FLOW ALOFT WILL
HOLD AFTERNOON HIGHS TODAY MAINLY IN THE LOWER TO MID 90S. OVERNIGHT
LOWS TONIGHT WILL BE MAINLY IN THE LOWER TO MID 70S.
HUBER
.LONG TERM...
BY SATURDAY MORNING THE MID LEVEL TROUGH AXIS WILL STRETCH
NORTHEASTWARD FROM SOUTHERN NEW MEXICO ACROSS THE NORTHERN
PANHANDLE AND INTO THE CENTRAL PLAINS. THE SLOW MOVING UPPER
TROUGH AXIS WILL FINALLY MOVE EAST OF THE FORECAST AREA BY LATE
SUNDAY. UNTIL THEN...ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
POSSIBLE OVER MUCH OF THE FORECAST AREA...FAVORING THE WESTERN AND
NORTHERN CWA.
WITH AN INCREASE IN CLOUD COVER...AFTERNOON HIGHS WILL REMAIN IN
THE LOW TO MID 90S THROUGH THE WEEKEND. MORNING LOWS WILL BE IN
THE LOWER 70S.
UPPER LEVEL HILL PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF
THE DEPARTING UPPER LEVEL TROUGH INTO THE FIRST OF THE COMING
WEEK. THE CENTER OF THE UPPER LEVEL HIGH WILL SETTLE OVER NEW
MEXICO. WITH THE UPPER RIDGE AND SUNNY SKIES DOMINATING THE AREA
AT LEAST THROUGH THE MIDDLE OF NEXT WEEK...AFTERNOON TEMPERATURES
WILL EDGE A LITTLE HIGHER TO THE MID TO UPPER 90S. LOOKING FOR A
DRY FORECAST FOR THE REMAINDER OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 93 73 95 73 94 / 30 20 20 20 20
SAN ANGELO 94 73 95 73 95 / 20 20 20 20 10
JUNCTION 93 74 92 71 93 / 20 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1150 PM CDT THU AUG 23 2012
.AVIATION...
VFR WITH AN INCREASING COVERAGE OF SHRA AND SOME TSRA EARLY THIS
NIGHT. OUTFLOW BOUNDARY FROM STORMS HAS JUST PUSHED ACROSS LBB
WITH GUSTY WESTERLY WINDS...ALTHOUGH NEGATIVE IMPACTS BEYOND THIS
ARE NOT IN THE OFFING AS STORMS HAVE MINIMAL INSTABILITY TO WORK
WITH FOR STRONG OR SEVERE WEATHER. REDUCED COVERAGE OF STORMS
DEVELOPING WEST OF CDS APPEARS BEST HANDLED WITH A TEMPO THROUGH
09Z. ADDITIONAL PRECIP WILL SPREAD NORTHEAST FROM SERN NM THROUGH
THE PRE-DAWN HOURS...BUT A GENERAL DECAYING TREND IS EXPECTED.
CEILINGS COULD LOWER TO LOW VFR LEVELS AT THE TERMINALS ESPECIALLY
IN THE WAKE OF THE PRECIPITATION. SOME CLEARING FRI AFTN SHOULD
YIELD ANOTHER CHANCE OF TSRA AHEAD OF A DEVELOPING DRYLINE AND
STRONG UPPER TROUGH FOR AUGUST STANDARDS. INITIAL INSPECTION OF
NEW MODEL DATA SUGGESTS POTENTIAL FOR SOME SEVERE TSRA...BUT
LATER SHIFTS WILL INVESTIGATE THIS THREAT IN MORE DETAIL.
&&
.PREV DISCUSSION... /ISSUED 929 PM CDT THU AUG 23 2012/
UPDATE...
LARGE BUT LOOSELY ORGANIZED LINE OF SHOWERS AND STORMS WAS FOUND
STRETCHING FROM DALHART SOUTH TO THE UPPER RIO GRANDE LATE THIS
EVENING IN ADVANCE OF AN UPPER TROUGH CURRENTLY IN CENTRAL NEW
MEXICO. RECENT IR SATELLITE IMAGERY CONFIRMS A DECAYING PROCESS
UNDERWAY WITH THE CONVECTION OVER THE MIDDLE EXTENT OF THE LINE
/ROUGHLY NEAR CLOVIS/ WITH RENEWED DEVELOPMENT FARTHER SOUTH FROM
EASTERN LEA COUNTY INTO THE FAR SOUTHWEST SOUTH PLAINS ATTENDANT
WITH AN APPARENT MCV PER REGIONAL 88D DATA. ALTHOUGH MINIMAL CAPE
WILL GOVERN THE REMAINDER OF THE OVERNIGHT...STEADY LIFT AND
SLIGHTLY DEEPER MOISTURE IN ADVANCE OF THIS CONVECTION SHOULD
SUSTAIN ISOLATED TO SCATTERED STORMS OVER THE REMAINDER OF THE
SOUTH PLAINS AS THIS ACTIVITY CONTINUES STEADILY EAST. BUMPED POPS
UP ACCORDINGLY THROUGH 06Z WITH REDUCED VALUES THEREAFTER AS
CONVECTION SLOWLY WANES AND OUTRUNS THE UPPER SUPPORT. RECENT RUNS
OF THE HRRR ARE PERFORMING REASONABLY WELL IN DEPICTING THE
AFOREMENTIONED DECAYING TREND NEAR CLOVIS WITH PREFERRED
DEVELOPMENT FARTHER SOUTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 88 64 90 64 / 60 20 20 20 20
TULIA 66 87 66 90 65 / 50 20 30 20 30
PLAINVIEW 67 86 66 90 66 / 50 20 30 20 30
LEVELLAND 66 86 67 93 67 / 60 20 20 20 20
LUBBOCK 69 89 68 93 68 / 50 20 20 20 20
DENVER CITY 64 87 68 94 67 / 60 20 20 20 20
BROWNFIELD 64 87 67 94 68 / 60 20 20 20 20
CHILDRESS 70 88 70 94 70 / 30 30 30 20 30
SPUR 68 89 69 93 70 / 30 30 30 20 20
ASPERMONT 71 90 72 96 72 / 30 30 30 20 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1134 PM CDT THU AUG 23 2012
.AVIATION...
AN UPPER LOW CAN BE SEEN SPINNING OVER THE FOUR CORNERS REGION
THIS EVENING ON THE LATEST SATELLITE LOOP. THE SYSTEM IS FORECAST
TO WORK ITS WAY EAST INTO THE PLAINS BEFORE OPENING UP AND
WEAKENING LATE IN THE WEEKEND. UNTIL THEN...LOW LEVEL MOISTURE
WILL GRADUALLY INCREASE ACROSS NORTH TEXAS OVER THE NEXT 48 HOURS
AHEAD OF THIS FEATURE. THUNDERSTORMS ARE EXPECTED TO DEVELOP A BIT
CLOSER TO THE AREA FRIDAY AFTERNOON AND EVENING AS THE UPPER LOW
APPROACHES THE TX/NM BORDER. IT STILL LOOKS LIKE THE BEST CHANCE
FOR CONVECTION WILL BE NORTHWEST OF TAF SITES...SO WILL NOT
MENTION IN THE LOCAL TAFS AT THIS TIME. HOWEVER...WILL NEED TO
KEEP AN EYE ON FUTURE GUIDANCE AND TRENDS FRIDAY AFTERNOON.
SURFACE WINDS HAVE DISPLAYED MORE OF AN EAST COMPONENT THAN THE
PAST SEVERAL MODEL RUNS HAVE SHOWN AND BELIEVE THIS COULD CONTINUE
FOR ANOTHER DAY. SPEEDS OF AROUND 10 KTS WILL REMAIN IN THE
FORECAST THROUGH FRIDAY NIGHT. SLIGHTLY HIGHER SPEEDS ARE LIKELY
ON SATURDAY AS THE GRADIENT TIGHTENS A BIT MORE. OTHERWISE...WILL
KEEP THE TEMPO MVFR DECK IN AT ALL SITES FOR FRIDAY MORNING AND
INTRODUCE THE RETURN OF MVFR STRATUS IN THE EXTENDED DFW TAF.
30
&&
.PREV DISCUSSION... /ISSUED 302 PM CDT THU AUG 23 2012/
CONVECTION FROM CHILDRESS TO SNYDER REMAINS WELL ELEVATED...WITH
BASES AOA 10KFT AGL. AS THE ACTIVITY MOVES EAST...IT WILL ENTER
AN AREA OF DEEPER MID-LEVEL MOISTURE. AS THE STORMS INGEST THIS
AIR...THE DCAPE (IN A LAGRANGIAN SENSE) WILL DIMINISH
CONSIDERABLY...AND THE THREAT OF DOWNBURST WINDS WILL BE
NEGLIGIBLE...DESPITE THE HIGH BASES. WITH WEAK SHEAR AND MOIST
ADIABATIC LAPSE RATES ALOFT...THE CONVECTION IS UNLIKELY TO
INTENSIFY...BUT IT MAY HOLD TOGETHER LONG ENOUGH TO REACH FAR
WESTERN ZONES LATE THIS AFTERNOON OR EARLY EVENING BEFORE
DISSIPATING. THE CU FIELD JUST WEST OF THE CWA IS BASED AROUND
5KFT AND APPEARS TO BE CAPPED...BUT WITH ANY FORCING ABOVE
800MB...THE MINIMAL INHIBITION CURRENTLY IN PLACE SHOULD BE ERODED
SUFFICIENTLY TO ALLOW SOME CELLS TO BECOME SURFACE-BASED.
REGARDLESS...THE BOUNDARY-LAYER INSTABILITY IS UNIMPRESSIVE...AND
ENTRAINING THIS SURFACE AIR WOULD ONLY FURTHER DECREASE THE
DOWNBURST THREAT.
SEA BREEZE CONVECTION IS CURRENTLY CONFINED TO THE HOUSTON METRO
AREA. AS SUCH...CONFIDENCE IS DIMINISHING FURTHER IN THE POTENTIAL
FOR ANY PROPAGATING OUTFLOW BOUNDARIES REACHING THE CWA. AS WITH
PREVIOUS RUNS...THE 18Z RUC MAINTAINS SOME CONVECTIVE CELLS IN FAR
SOUTHEAST ZONES...WHERE THE PROFILE WILL BECOME INCREASINGLY
TROPICAL. WITH DEEPENING MOISTURE AND DIMINISHING SUBSIDENCE...
WILL CONTINUE TO CARRY SOME ISOLATED MENTION IN THE SOUTHEAST.
LAS VEGAS HAD TALLIED ONLY 1.53 INCHES OF PRECIP IN 11 MONTHS
BEFORE RECEIVING A DELUGE OF 1.65 INCHES ON WEDNESDAY. (THIS
EASILY BROKE THE DAILY RECORD OF 0.23 INCHES.) THE OFFENDING
SHORTWAVE CONTINUES TO DEEPEN OVER THE FOUR CORNERS...WITH
WIDESPREAD CONVECTION DOWNSTREAM ACROSS NEW MEXICO AND COLORADO.
AS THE SYSTEM REACHES THE TEXAS PANHANDLE...IT WILL BE IN PHASE
WITH THE CYCLONE NEAR THE CANADIAN BORDER. AS A RESULT...THE
FEATURE WILL LIKELY SHEAR AND BE DRAWN NORTHWARD. WITH THE ENERGY
FARTHER NORTH...THE PRECIPITATION CHANCES FOR NORTH TEXAS THIS
WEEKEND WOULD BE REDUCED. WILL MAINTAIN BEST CHANCES GENERALLY
ALONG THE RED RIVER VALLEY. DESPITE THE LIKELY EVOLUTION OF THE
CONVECTIVE EVENT...EXTENDED GUIDANCE IS STILL FAVORING A RESULTING
EROSION OF THE RIDGE ABOVE NORTH TEXAS.
THE SHORTWAVE (AND MUCH LARGER CYCLONE) WILL ALLOW MILDER AIR TO
INVADE THE CENTRAL PLAINS. BUT WITH NEAR NORMAL TEMPERATURES
EXPECTED WITH THE SURFACE ANTICYCLONE...IT WOULD SUGGEST A
TENDENCY FOR THE ASSOCIATED FRONTAL BOUNDARY TO FAIL TO PENETRATE
THE SOUTHERN PLAINS. BUT IF THE RIDGE DOES ERODE ENOUGH TO ALLOW
FOR NORTHERLY FLOW...THE BOUNDARY COULD CERTAINLY REACH NORTH
TEXAS. EVEN THE ECMWF...WHICH PROJECTS A MID-LEVEL RIDGE AXIS FROM
TEXAS INTO THE PRAIRIE PROVINCES EARLY NEXT WEEK...ALLOWS
NORTHERLY SURFACE FLOW TO SLIDE DOWN THE MISSISSIPPI VALLEY AND
BACKDOOR INTO NORTH TEXAS...INDUCED BY THE PROXIMITY OF ISAAC.
(THE LATEST ECMWF RUN TAKES ISAAC INTO DFW...BUT THE EURO WAS
ALREADY A FAR WESTERN OUTLIER...SO DO NOT HAVE MUCH CONFIDENCE IN
THIS LATEST SOLUTION.) EXPECT A WARMING TREND NEXT WEEK...DESPITE
ANY LIGHT NORTH WINDS. WHATEVER TRACK ISAAC TAKES...NORTH TEXAS
WOULD LIKELY BE IN A SUBSIDENT ZONE. A MORE EASTERLY TRACK WOULD
ALLOW THE PLAINS RIDGE TO INTENSIFY...WHILE A MORE WESTERLY TRACK
COULD PUT EAST TEXAS WITHIN THE RING OF STRONG DOWNWARD MOTION
AROUND THE PERIPHERY OF THE CIRRUS SHIELD. TEMPERATURES MAY REACH
THE UPPER 90S BY DAY 7 (THURSDAY AUGUST 30).
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 76 93 76 94 77 / 5 10 20 20 20
WACO, TX 74 94 75 94 76 / 5 10 10 10 10
PARIS, TX 70 91 71 91 73 / 5 20 30 50 20
DENTON, TX 73 93 75 94 76 / 5 10 20 20 20
MCKINNEY, TX 70 91 73 91 75 / 5 20 20 30 20
DALLAS, TX 75 91 76 94 77 / 5 10 20 20 20
TERRELL, TX 72 91 73 92 75 / 5 20 20 20 20
CORSICANA, TX 73 92 73 93 75 / 5 10 20 20 10
TEMPLE, TX 73 94 73 94 74 / 10 10 10 10 10
MINERAL WELLS, TX 72 94 72 94 73 / 5 10 20 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
240 AM CDT FRI AUG 24 2012
.SHORT TERM...THROUGH SUNDAY
239 AM CDT FRI AUG 24 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS MORNING SHOWS AN AREA OF LOW PRESSURE OVER
SOUTHEAST MONTANA. A WEAK WARM FRONT EXTENDS FROM THE LOW ACROSS
CENTRAL MINNESOTA INTO NORTHERN WISCONSIN. REGIONAL RADARS WERE
SHOWING A LINE OF SHOWERS AND THUNDERSTORMS FROM LAKE SUPERIOR
INTO NORTHEAST IOWA.
THE ONGOING CONVECTION WAS BEING FUELED BY A SHORT WAVE TROUGH
MOVING ACROSS MINNESOTA. THE 24.05Z RAP INDICATES THIS WAVE WILL
MOVE EAST INTO WISCONSIN IN THE PRE-DAWN HOURS AND THEN AWAY FROM
THE REGION AFTER SUNRISE. THE ACTIVITY CURRENTLY LOOKS TO BE ON
THE EASTERN EDGE OF THE MU CAPE GRADIENT AS THIS QUICKLY DROPS TO
250 J/KG OR LESS ACROSS WESTERN INTO CENTRAL WISCONSIN. BOTH THE
24.00Z HIRES ARW AND NMM SUGGEST THE ACTIVITY IS THE STRONGEST NOW
AND WILL DISSIPATE THROUGH THE REMAINDER OF THE NIGHT AS IT MOVES
OUT OF THE CAPE AXIS. WILL MONITOR THE LATEST RADAR TRENDS AND
MAKE ADJUSTMENTS AS NEEDED BUT CURRENTLY FEEL THE BEST CHANCE OF
ANY ACTIVITY STILL TO BE ONGOING AFTER 12Z IS ACROSS NORTH CENTRAL
WISCONSIN WHERE THE CAPE IS A LITTLE BETTER AND THE MOISTURE
TRANSPORT SHOULD BE THE STRONGEST. FOR THE AFTERNOON...THE 24.00Z
NAM AND GFS INDICATE ANOTHER WEAK SHORT WAVE TROUGH WILL TRACK
ACROSS NORTHERN MINNESOTA TOWARD LAKE SUPERIOR. THIS WAVE WILL
PRODUCE ONLY SOME WEAK VORTICITY ADVECTION IN THE 500-300 MB LAYER
NORTH OF THE AREA. SOME WEAK ISENTROPIC UP GLIDE WILL CONTINUE
OVER THE REMAINS OF THE WARM FRONT WITH THE NAM SHOWING AROUND 2
UBAR/S ACROSS NORTHWEST INTO CENTRAL WISCONSIN. THIS MAY BE ENOUGH
TO GENERATE SOME ADDITIONAL WIDELY SCATTERED CONVECTION AND WILL
KEEP THE 20 PERCENT CHANCES IN THE I94 CORRIDOR.
AFTER TODAY...THE NEXT CHANCE OF RAIN WILL BE SATURDAY THROUGH
SUNDAY. A LARGE UPPER LEVEL LOW OVER WESTERN CANADA WILL TRACK
EAST WHILE REMAINING NORTH OF THE BORDER. AS IT DOES...A WEAK
UPPER LEVEL LOW OVER THE FOUR CORNERS WILL CONTINUE TO WEAKEN AND
BECOME AN OPEN WAVE WHILE BEING PULLED NORTHEAST AHEAD OF THE
CANADIAN UPPER LEVEL LOW. THE MODELS INDICATE THE REMAINS OF THE
FOUR CORNERS UPPER LEVEL LOW WILL COME THROUGH IN A COUPLE OF
PIECES WITH THE FIRST MOVING ACROSS THE REGION SATURDAY AND THE
SECOND SATURDAY NIGHT AND SUNDAY. NONE OF THE MODELS PRODUCE MUCH
VORTICITY ADVECTION WITH THE NAM AND 23.12Z ECMWF SHOWING 2 PVU/S
OR LESS WHILE THE 24.00Z GFS IS A LITTLE STRONGER SHOWING UP TO 4
PVU/S. A WEAK COLD FRONT OR TROUGH OF LOW PRESSURE SHOULD MOVE
SLOWLY ACROSS THE AREA WITH THE SHORT WAVE TROUGHS. SOME WEAK
FRONTOGENESIS IN THE 1000-700 MB LAYER SHOULD OCCUR WITH THIS
FEATURE SATURDAY AFTERNOON AND THERE SHOULD BE SOME PERSISTENT UP
GLIDE OF 1 TO 3 UBAR/S ON THE 310K SURFACE UNTIL THIS FEATURE
MOVES THROUGH THE AREA. SINCE THE FORCING WITH THESE WAVES IS NOT
THAT STRONG EXPECTING MAINLY SCATTERED CONVECTION TO OCCUR
SATURDAY AS THE LEAD WAVE COMES IN. THE COVERAGE COULD BE A LITTLE
BIT BETTER SATURDAY NIGHT ACROSS THE SOUTH AHEAD OF THE SECOND
WAVE WHERE THE VORTICITY ADVECTION COULD BE A LITTLE BIT STRONGER.
THE SEVERE POTENTIAL LOOKS PRETTY LOW SATURDAY AND SATURDAY NIGHT
WITH ML CAPES OF 500 J/KG OR LESS EXPECTED AND THE 0-6 KM SHEAR IS
ONLY AROUND 25 KNOTS.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
239 AM CDT FRI AUG 24 2012
ONCE THIS SYSTEMS MOVES OUT...A LARGE AREA OF HIGH PRESSURE WILL
BUILD IN OVER THE UPPER MIDWEST AND SHOULD REMAIN THROUGH MUCH OF
THE PERIOD. TOWARD THE END OF THE PERIOD...THE GFS IS TRYING TO
BRING A SHORT WAVE TROUGH AND UPPER LEVEL LOW THROUGH THE TOP OF
THE UPPER LEVEL RIDGE AND ACROSS SOUTHERN CANADA AND THE UPPER
MIDWEST. THE 24.00Z ECMWF MAINTAINS THE UPPER LEVEL RIDGE OVER THE
AREA WITH ANY TROUGHING OVER SOUTHWEST CANADA INTO THE NORTHERN
ROCKIES. WILL TREND TOWARD THE ECMWF SOLUTION AND KEEP THE ENTIRE
PERIOD DRY.
&&
.AVIATION...THROUGH 06Z SATURDAY
1140 PM CDT THU AUG 23 2012
MAIN FOCUS IS ON PRECIPITATION CHANCES EARLY IN THE FORECAST.
CLUSTER OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS PERSISTS
ACROSS CENTRAL MINNESOTA...WITH OTHERS DEVELOPING OVER WEST
CENTRAL WISCONSIN AND INTO SOUTHEAST MINNESOTA. MAJORITY OF THESE
REMAIN NORTH OF THE TAF SITES. CANNOT RULE OUT A FEW SHOWERS
AFFECTING EITHER TAF SITES PRIOR TO 12Z...IN RESPONSE TO A
LOW PRESSURE TROUGH MOVING EAST FROM CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...THE BEST FORCING LOOKS TO REMAIN NORTH OF
THE TAF SITES...THUS ONLY VCSH REMAINS MENTIONED IN THE TAFS. VFR
CONDITIONS ARE EXPECTED ANYWAY DUE TO DRY LOW LEVEL AIR. IN
FACT...THE DRY LOW LEVEL AIR WILL REMAIN IN PLACE THROUGH FRIDAY
NIGHT...HELPING TO MAINTAIN VFR CONDITIONS. PLAN ON WINDS TO PICK
UP SOME DURING THE AFTERNOON HOURS...PARTICULARLY AT KRST BEING
MORE EXPOSED. GUSTS THERE COULD APPROACH 20 KT. EXPECT WINDS TO
DIMINISH DURING THE EVENING WITH COOLING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
239 AM CDT FRI AUG 24 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT THU AUG 23 2012
.SHORT TERM...TONIGHT
723 PM CDT THU AUG 23 2012
MAIN FORECAST CONCERN IS IF CONVECTION WILL MOVE INTO AND/OR
DEVELOP OVER THE FORECAST AREA TONIGHT.
00Z WATER VAPOR LOOP SHOWED A SHORTWAVE TROUGH ACROSS WESTERN
MINNESOTA. WEAK DPVA FORCING AHEAD OF THIS SHORTWAVE COMBINED WITH
WARM ADVECTION...AND MORE IMPORTANTLY INSTABILITY...HAS LED TO
SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT FROM SOUTHWEST INTO
CENTRAL MINNESOTA. MUCH OF THIS ACTIVITY WAS ALSO ON A WARM FRONT.
23Z RAP ANALYSIS DEPICTED MLCAPE VALUES AROUND 1500 J/KG WITH
MLCIN LESS THAN 50 J/KG WHERE THESE STORMS HAVE OCCURRED.
MODELS ARE IN GOOD AGREEMENT LIFTING THE SHORTWAVE TROUGH OVER
WESTERN MINNESOTA TO THE NORTHEAST TONIGHT...STRETCHING FROM
WESTERN LAKE SUPERIOR INTO NORTHERN WISCONSIN BY 12Z FRIDAY. BIG
QUESTION MARK IS HOW MUCH PRECIPITATION OCCURS WITH THIS TROUGH.
CONVECTION THUS FAR AT LEAST OVER SOUTHWEST MINNESOTA REALLY
SEEMS TIED TO DIURNAL INSTABILITY. OVER THE NEXT FEW HOURS...THE
MLCIN INCREASES GREATLY...OVER 100 J/KG BY 02Z PER THE RAP MODEL.
THEREFORE...THINK THOSE IN SOUTHWEST MINNESOTA WILL DISSIPATE
BEFORE THEY HAVE MUCH OF A CHANCE TO HEAD EAST OR NORTHEAST WITH
THE SHORTWAVE TROUGH. THOSE STORMS MORE OVER CENTRAL MINNESOTA ARE
MORE ON THE NOSE OF 850MB MOISTURE TRANSPORT...WHICH SHIFTS
NORTHEAST WITH THE SHORTWAVE TROUGH. SO ALTHOUGH MODELS SUCH AS
THE 23.18Z NAM/GFS AND 23.12Z ECMWF BRING CONVECTION INTO
NORTHWEST PORTIONS OF THE AREA...DEFINITELY HAVE DOUBTS. IN
FACT...THE 23.12Z HIRESW-ARW MODEL SUGGESTS THAT MUCH OF THE
CURRENT CONVECTION DISSIPATES BY 06Z...LEAVING THE OVERNIGHT DRY.
23.21Z HRRR ALSO HAS TRENDED DRIER...WITH THE EXCEPTION OF SOME
SCATTERED ELEVATED CONVECTION IT DEVELOPS ALONG/NORTH OF I-94
AFTER 10Z. FOR NOW...HAVE DELAYED ARRIVAL OF ANY PRECIPITATION
CHANCES TO AT LEAST 03Z...AND AFTER 03Z MOSTLY LOWERED
PRECIPITATION CHANCES EXCEPT FOR THE TAYLOR/CLARK AREA. THE REASON
FOR NOT ADJUSTING CHANCES IN TAYLOR/CLARK IS INDICATIONS OF
INCREASING 310K ISENTROPIC LIFT...REFLECTED IN BOTH THE 23.18Z NAM
AND 23.21Z HRRR.
IN SUMMARY...CONCERNED THAT NOT MUCH MAY HAPPEN FOR THE FORECAST
AREA TONIGHT. WILL WATCH CONVECTIVE TRENDS OVER THE NEXT FEW HOURS
AND ADJUST PRECIPITATION CHANCES AS NECESSARY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
240 PM CDT THU AUG 23 2012
23.12Z GFS/EC SHOW SUNDAY NIGHT THROUGH TUESDAY NIGHT LOOKING DRY AND
WARM AS A MID-LEVEL RIDGE OF HIGH PRESSURE BUILDS INTO THE CENTRAL
CONUS. LOOK FOR HIGHS MONDAY AND TUESDAY IN THE UPPER 70S TO MIDDLE
80S. BY WEDNESDAY INTO THURSDAY...WILL BE WATCHING LOW PRESSURE PUSH
ACROSS THE NORTHERN PLAINS TOWARD THE AREA. THIS SETS UP WAA
SCENARIO ACROSS THE AREA WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS WEDNESDAY/WEDNESDAY NIGHT. OTHERWISE...LOOKS LIKE
ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THURSDAY WITH HIGHS
TOPPING OFF IN THE 80S.
&&
.AVIATION...THROUGH 06Z SATURDAY
1140 PM CDT THU AUG 23 2012
MAIN FOCUS IS ON PRECIPITATION CHANCES EARLY IN THE FORECAST.
CLUSTER OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS PERSISTS
ACROSS CENTRAL MINNESOTA...WITH OTHERS DEVELOPING OVER WEST
CENTRAL WISCONSIN AND INTO SOUTHEAST MINNESOTA. MAJORITY OF THESE
REMAIN NORTH OF THE TAF SITES. CANNOT RULE OUT A FEW SHOWERS
AFFECTING EITHER TAF SITES PRIOR TO 12Z...IN RESPONSE TO A
LOW PRESSURE TROUGH MOVING EAST FROM CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...THE BEST FORCING LOOKS TO REMAIN NORTH OF
THE TAF SITES...THUS ONLY VCSH REMAINS MENTIONED IN THE TAFS. VFR
CONDITIONS ARE EXPECTED ANYWAY DUE TO DRY LOW LEVEL AIR. IN
FACT...THE DRY LOW LEVEL AIR WILL REMAIN IN PLACE THROUGH FRIDAY
NIGHT...HELPING TO MAINTAIN VFR CONDITIONS. PLAN ON WINDS TO PICK
UP SOME DURING THE AFTERNOON HOURS...PARTICULARLY AT KRST BEING
MORE EXPOSED. GUSTS THERE COULD APPROACH 20 KT. EXPECT WINDS TO
DIMINISH DURING THE EVENING WITH COOLING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
240 PM CDT THU AUG 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
754 AM EDT FRI AUG 24 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EDT FRI AUG 24 2012
00Z RAOBS AND RUC ANALYSIS INDICATES ZONAL FLOW ALOFT DOWNSTREAM OF
SHARP TROUGH OVER WESTERN CANADA AND ON PERIPHERY OF BROAD RIDGE
OVER CENTRAL CONUS. AT THE SFC...DISJOINTED COMPLEX OF TROUGHS ARE
PRESENT FROM SAKSATCHEWAN INTO NORTH DAKOTA.
HAVE A DOWNRIGHT MESS OF CONVECTION OVER UPR LAKES THIS MORNING
AHEAD OF PAIR OF STRONGER SHORTWAVE TROUGHS MOVING INTO NORTHWEST
ONTARIO AND INTO SOUTHWEST WISCONSIN. H85 WARM ADVECTION IS
SUPPORTING MORE WEST-TO-EAST ORIENTED SHRA/TSRA OVR LK SUPERIOR
WHILE HEIGHT FALLS AND H85-H7 MOISTURE ADVECTION ALONG 2-5KM MUCAPE
RIBBON AND ALONG WEST EDGE OF H85 JET IS SPURRING ON MULTIPLE
CLUSTERS OF MODERATE-HEAVY SHRA/TSRA FROM SOUTHWEST LK SUPERIOR INTO
NORTHWEST WI AND INTO SOUTHWEST WI. ACTIVITY OVR SOUTHWEST WI IS
MORE ORGANIZED WITH SHARPER HEIGHT FALLS OVR THAT AREA DUE TO
SHORTWAVE. ENTIRE AREA IS WITHIN INFLUENCE OF BROAD DIVERGENCE
ALOFT AS H3 JET STREAK SURGES IN FROM THE NORTHERN PLAINS.
CURRENT RADAR TRENDS AND EXPECTED POSITION OF LOW-LEVEL JET THROUGH
MID MORNING SUGGESTS THAT SHRA/TSRA OVER WESTERN LK SUPERIOR WILL
LIFT ACROSS KEWEENAW AND REST OF LK SUPERIOR THIS MORNING. IT APPEARS
THAT CONVECTION OVER SOUTHWEST WISCONSIN WILL NOT MAKE MUCH PUSH
INTO UPR MICHIGAN AS PRIMARY SHORTWAVE STAYS MAINLY OVR WISCONSIN.
LOOKS LIKE MAIN EFFECT OF BOTH AREAS OF CONVECTION WILL BE TO KEEP
SCT-BKN MID CLOUDS IN OVER MOST CWA THIS MORNING...BUT DO EXPECT
SOME HEATING. BETTER HEATING OCCURS EARLY TO MID AFTN AND COULD TIME
OUT WELL WITH ARRIVAL OF SURGE OF H85-H7 MOISTURE FROM THE SOUTHWEST.
THERE IS CURRENTLY A VERY SHARP EDGE TO THE H7 MOISTURE AS SEEN WITH
ABRUPT CLEARING SEEN OVER SOUTHERN MINNESOTA. SREF /WHICH HAS OKAY
HANDLE ON CURRENT CONVECTIVE TRENDS/ BLASTS THIS DRY MID-LEVEL AIR
INTO WEST THIRD BY EARLY AFTN WITH MOISTURE GRADIENT SETTING UP OVR
CENTRAL CWA. DEPENDING ON EXTENT OF HEATING...INSTABILITY COULD
INCREASE WITH ML BASED CAPES OVR 1000 J/KG IN THE CNTRL CWA 18Z-22Z.
TRIGGER WOULD BE SHORTWAVE TROUGH AND SFC-H85 THETA-E ADVECTION AND
MAYBE DEVELOPING LK BREEZES /THOUGH WITH FAIRLY STRONG 950MB INTO
AFTN NOT AS CONFIDENT IN THIS POSSIBLE TRIGGER/. DEEP LAYER SHEAR
ENDS UP AROUND 30 KTS DURING THE AFTN...SO AT LEAST BRIEF
ORGANIZATION/STRONG STORMS SEEMS POSSIBLE GIVEN THE INSTABILITY.
OVERALL...THINK SETUP CONTINUES TO JUSTIFY GOING FCST OF SCT POPS
MAINLY IN THE AFTN...HIGHEST OVER CENTRAL CWA. CONTINUED TO TRIM
POPS OVER WEST...JUST TOO MUCH DRYING TO TRIGGER ANY ADDITIONAL
CONVECTION THERE. BASED ON CURRENT RADAR/SATELLITE TRENDS...THINK
CLEARING IS LIKELY OVR MOST OF CWA THROUGH THE MORNING. SO...WARMER
TEMPS AS NAM INDICATES ARE PREFERRED. BASED ON MIXING TO H85 TEMPS
NEAR +19C...MAX TEMPS MAY TOP OUT WELL INTO THE UPPER 80S. WARM
START TO THE DAY WILL NOT HINDER THIS PROCESS EITHER.
SHORTWAVE TROUGH/MOISTURE ADVECTION CRUISES EAST EARLY THIS EVENING
AND OTHER THAN SOME SMALL CHANCES HAVE PRETTY MUCH ENDED POPS BTWN
00Z-06Z FOR ALL BUT EAST AND SOUTH FRINGES OF CWA. NAM IS QUITE
BULLISH ON POPS FOR OVERNIGHT TONIGHT...MUCH MORE SO THAN OTHER
MODELS. LOOKING AT SOUNDINGS...MOISTURE IS BACK ON THE INCREASE
ALOFT /ROUGHLY ABOVE H7/. LAPSE RATES KIND OF STEEP H7-H5...TOWARD
7C/KM. A LOT OF DRY AIR BLO H7 AND STRONG LIFT LOOKS TO BE LACKING.
MAY SEE A WEAK SHORTWAVE STREAKING OUT AHEAD OF DEEPER WESTERN
CANADA TROUGH WHICH COULD ENHANCE LIFT. KEPT ISOLD MENTION FOR
SHRA/TSRA OVER NORTH TWO-THIRDS OF CWA OUT INTO LK SUPERIOR ALONG
AND NORTH OF H85 FRONT...BUT EVEN THIS POSSIBILITY WILL DIMINISH
LATE IN THE NIGHT AS H7 MOISTURE TRANSPORT WEAKENS AS DOES UVM IN
THE H7-H5 LAYER. SHOULD BE ANOTHER WARM NIGHT /READINGS IN THE 60S/
DUE TO PERSISTENT SOUTH WINDS OUT AHEAD OF SFC LOW DEEPENING OVR
CANADIAN PRAIRIES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 523 AM EDT FRI AUG 24 2012
SATURDAY...AS THE MID LEVEL LOW OVER SASK LIFTS INTO NORTHERN
MANITOBA RIDGING WILL PREVAIL DOWNSTREAM OVER THE GREAT LAKES. AS A
RESULT...DRY MID LEVELS AND CAPPNIG SHOULD LIMIT ANY PCPN
CHANCES...PER ECMWF/GFS. HOWEVER...SINCE THE REGIONAL GEM AND NAM
CONTINUE TO SUGGEST THAT A WEAK SHORTWAVE TROUGH LIFTING OUT OF THE
UPPER MS VALLEY COULD BRING SOME PCPN INTO THE WEST...SLIGHT CHANCE
WAS MENTIONED IN THE LATE AFTERNOON. WITH PLENTY OF SUNSHINE/MIXING
AND 850 MB TEMPS INTO THE 18C-20C RANGE...EXPECT MAX READINGS INTO
THE UPPER 80S WITH A FEW 90S POSSIBLE IN SW FLOW DOWNSLOPE LOCATIONS.
SATURDAY NIGHT AND SUNDAY...THE MODELS SUGGEST THAT THE STRONGER
FORCING AND HEIGHT FALLS AHEAD OF THE MID LEVEL LOW WILL REMAIN
NORTH OF UPPER MICHIGAN WHILE A WEAKER SHORTWAVE MOVING OUT OF THE
CNTRL PLAINS AND GREATER INSTABILITY WILL REMAIN TO THE SOUTH.
SO...THE DRIER QPF FROM THE ECMWF/GEM SCENARIO WAS PREFERRED
COMPARED TO THE GFS. NEVERTHELESS...SCT SHRA/TSRA ARE STILL EXPECTED
AS THE SFC TROUGH AND AXIS OF HIGHER MOISTURE MOVE THROUGH THE CWA.
ANY LINGERING PCPN SHOULD EXIT THE CNTRL CWA SUN EVENING AND THE
EAST OVERNIGHT.
MON-THU...THE MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD
PATTERN AMPLIFICATION AS A TROUGH MOVES INTO THE WRN CONUS AND RIDGE
DEVELOPS FROM THE CNTRL ROCIES INTO THE PLAINS. THE NW FLOW PATTERN
INTO THE UPPER GREAT LAKES WILL BRING A SFC HIGH AND COOLER DRIER
AIR INTO UPPER MI MON-TUE WHICH WOULD GIVE WAY TO WARMING BY
WED-THU. CONFIDENCE IN PCPN POTENTIAL BY WED-THU WITH POTENTIAL
FRONTAL SYSTEM AND HEIGHT FALLS IS LOW GIVEN INCREASING MODEL SPREAD
AND RUN TO RUN VARIATION WITH THE STRENGTH OF THE RIDGE. SO
CONSENSUS SLIGHT CHANCE POPS WERE NOT ALTERED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 753 AM EDT FRI AUG 24 2012
LULL IN SHRA/TSRA THROUGH MID MORNING...BUT COULD SEE ANOTHER ROUND
OF SHRA/TSRA DEVELOP BY MID AFTERNOON WITH DAYTIME HEATING AND AS
UPPER DISTURBANCE SLIDES ACROSS UPPER MICHIGAN. BEST CHANCE OF
SHRA/TSRA LATER TODAY WILL BE AT KSAW AS SHARP DRYING WORKING IN
FROM NORTHERN PLAINS WILL RESTRICT DEVELOPMENT OVER WESTERN UPPER
MICHIGAN. SCT-BKN MID CLOUDS POSSIBLE TONIGHT. OVERALL...VFR
CONDITIONS WILL PREVAIL THROUGH TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 523 AM EDT FRI AUG 24 2012
SOUTH TO SOUTHEAST WINDS REMAIN STRONG TODAY ESPECIALLY OVER EASTERN
SECTIONS WHERE GUSTS MAY REACH 25-30 KTS AT HIGHER PLATFORMS AND
SHIP LEVEL. LOW-LEVEL JET AXIS FADES AWAY TONIGHT...SO WINDS SHOULD
DECREASE TO LESS THAN 20 KTS. WINDS EXPECTED TO REMAIN AT 20 KTS OR
LESS THROUGH THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK AS
STRONGEST PRESSURE GRADIENT STAYS WELL TO NORTH IN THE VICINITY OF
STRONG SFC LOW OVER HUDSON BAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
643 AM CDT FRI AUG 24 2012
.AVIATION...
FOR THE KLBF AND KVTN TERMINALS THROUGH 12Z SATURDAY.
FOR THE KLBF TERMINAL...ABUNDANT LOW LEVEL MOISTURE IS EXPECTED OVER
THE NEXT 24 HOURS...WHICH WILL LEAD TO PERIODS OF LOW LEVEL
CLOUDINESS OVER THE NEXT 24 HOURS. PERIODIC MVFR CIGS ARE EXPECTED
THROUGH EARLY AFTERNOON WITH VFR CIGS EXPECTED THROUGH MID EVENING.
WITH COOLING TEMPS AFTER SUNDOWN...LOW LEVEL CLOUDINESS WILL BEGIN
TO WORK BACK INTO SOUTHWESTERN NEBRASKA AFTER 04Z TONIGHT. BASED ON
THE LATEST SREF PROBABILITIES...NOT CONFIDENT ENOUGH YET TO PUT IFR
CIGS IN THE LAST 6 HRS OF THE FCST AND WILL OPT FOR MVFR CIGS ATTM.
AS FOR PRECIPITATION...COVERAGE IS EXPECTED TO BE SCATTERED SOUTH
AND EAST OF THE KLBF TERMINAL...WITH ISOLATED COVERAGE FCST IN THE
KLBF VICINITY. WITH THIS IN MIND...WILL FORGO MENTION OF TSRAS IN
THE 12Z KLBF TAF. WINDS OVER THE NEXT 24 HRS...WILL BE FROM THE
SOUTHEAST OR EAST SOUTHEAST AT UNDER 10 KTS.
FOR THE KVTN TERMINAL...LOW CLOUDINESS...PER SATELLITE
IMAGERY...WILL APPROACH THE KVTN TERMINAL AROUND 12Z THIS MORNING.
SINCE THE TERMINAL WILL BE ON THE NRN PERIPHERY OF THE LOW
CLOUDINESS...WILL HANDLE IT WITH A TEMPO GROUP THROUGH LATE MORNING.
EXPECT SOME SCATTERED TO BROKEN MID LEVEL CLOUDINESS TO DEVELOP
LATER THIS AFTERNOON WITH CIGS RANGING FROM 7000 TO 9000 FT AGL.
SOME LOW CLOUDINESS MAY WORK INTO NORTHERN NEBRASKA OVERNIGHT
TONIGHT IN ASSOC WITH A COOL FRONTAL BOUNDARY. WILL HANDLE THIS WITH
MVFR CIGS ATTM...AS SREF PROBABILITIES ARE LOW FOR SUB 1000 FT CIGS.
WINDS WILL BE FROM THE SOUTH AT 10 KTS THIS MORNING...INCREASING TO
10 TO 20 KTS THIS AFTERNOON...BEFORE DIMINISHING TO AROUND 10 KTS
TONIGHT. A SHIFT IN WIND DIRECTION TO THE NORTH IS EXPECTED TOWARD
DAYBREAK SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT FRI AUG 24 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CONCERNS THROUGH THE FIRST FEW DAYS OF THE FORECAST DEAL
WITH TEMPERATURES...CLOUD COVER...AND RAIN CHANCES THROUGH
SATURDAY.
ONGOING STORM COMPLEX BRINGING MUCH NEEDED RAINFALL ACROSS KANSAS
THIS MORNING...SPC MESOANALYSIS SHOWED STRONG MOISTURE ADVECTION
INTO THE STORMS...WHICH WAS ECHOED BY PROFILER DATA WITH 850MB
WINDS OF 35 TO 45KTS INTO THE SYSTEM. ANALYSIS ALSO SHOWED A
STRONG PRECIPITABLE WATER GRADIENT WITH 1.50 TO 2.00 INCHES ACROSS
KANSAS INTO EASTERN NEBRASKA...WHILE THE NORTHERN NEBRASKA
PANHANDLE WAS OBSERVING VALUES LESS THAN THREE QUARTERS OF AN
INCH. ALTHOUGH GOOD RAINFALL WAS OCCURRING OVER KANSAS...THE LOCAL
AREA STAYED DRY OVERNIGHT. THE AREA DID SEE SOME RAIN
YESTERDAY...HOWEVER AMOUNTS WERE LIGHT WITH KLBF BEING THE
WINNER OF THE DAY WITH 0.13 INCHES. THERE IS LIKELY A FEW
LOCATIONS OVER FRONTIER COUNTY THAT MAY HAVE GOTTEN A BIT MORE
RAINFALL DUE TO SOME LATE EVENING THUNDERSTORMS...HOWEVER NO
REPORTED AMOUNTS HAVE BEEN RECEIVED YET.
LOOKING AT WATER VAPOR IMAGERY...A STRONG UPPER LEVEL LOW WAS
SITUATED OVER THE FOUR CORNERS WITH A GOOD FLUX OF MOISTURE
STREAMING NORTHWARD AHEAD OF THIS SYSTEM. THIS HAS BEEN SEEN IN
THE INCREASE OF PRECIPITABLE WATER VALUES AS WAS MENTIONED ABOVE.
ALSO OF NOTE IN THE LARGE SCALE IS A SHORTWAVE TROUGH OVER THE
PACIFIC NORTHWEST...AS WELL AS TROPICAL STORM ISAAC IN THE
CARIBBEAN. CLOSER TO HOME...LOW PRESSURE WAS ANALYZED OVER
SOUTHEAST COLORADO...WITH A SECOND LOW CENTERED OVER EASTERN
MONTANA. SOUTHERLY WINDS WERE BRINGING MOISTURE IN FROM THE
SOUTH...HOWEVER A TIGHT MOISTURE GRADIENT EXISTED WITH DEWPOINTS
RANGING FROM THE 30S IN SOUTHWEST SOUTH DAKOTA TO THE MID AND UPPER
60S FROM SOUTHWEST INTO CENTRAL NEBRASKA.
FOR TODAY...CLOUD COVER WILL HAVE A LARGE IMPACT ON TEMPERATURES.
THERE IS CONSIDERABLE DIFFERENCES IN THE LOW LEVEL MOISTURE FIELDS
FOR THIS MORNING...WITH THE NAM BEING QUITE A BIT DRIER THAN THE
RAP/GFS SOLUTIONS. THE 11-3.9 IR AT 08Z WAS SHOWING THE
FOG/STRATUS EXPANDING QUITE A BIT SO WILL EDGE ON A MORE CLOUDY
FORECAST FOR TODAY. WITH THE MODELS NOT HANDLING THIS WELL HAVE
LOW CONFIDENCE ON HOW FAST THIS MOISTURE WILL SCOUR OUT TODAY.
EARLIER RAP RUNS HAD KEPT THE LOW CLOUDS IN THROUGH MUCH OF THE
DAY...HOWEVER LATEST /24.06Z RUN/ STARTS TO BREAK THINGS OUT
AROUND 18Z. NAM WOULD ALSO HAVE CLOUDS OUT BY 18Z. WITH NO REAL
FOCUS FOR MOISTURE CONVERGENCE THROUGH THE DAY BELIEVE THE LOW CLOUDS
WILL EVENTUALLY DISSIPATE. MAY START TO SEE SOME MID/HIGH LEVEL
CLOUDS MOVING IN THOUGH AT THIS POINT AS BOTH THE UPPER LOW OVER
THE FOUR CORNERS AND THE PACIFIC NORTHWEST SYSTEM MOVE EAST. SO AS
TEMPERATURES SHOULD START TO RECOVER /WITH GOOD WARMING POTENTIAL
IF SEVERAL HOURS OF SUNSHINE ARE REALIZED/ STILL WENT CONSERVATIVE
WITH HIGHS TODAY AND KEPT SOUTHERN AREAS IN THE MID 80S.
SOME MODELS WOULD SUGGEST PRECIPITATION THIS MORNING AND EARLY
AFTERNOON...BUT FROM THE LOOKS OF MOISTURE TRANSPORT
VECTORS...PRECIPITATION SHOULD BE PUSHED TO THE EAST SO KEPT THE
FORECAST THROUGH MID AFTERNOON DRY. BY 25.00Z THE SOUTHERN UPPER
LEVEL SYSTEM WILL BE OVER EASTERN COLORADO...WITH A SURFACE LOW
REMAINING JUST TO ITS EAST. THE LOW LEVEL JET DOES STRENGTHEN
CONSIDERABLY INTO THE EVENING AND OVERNIGHT HOURS...HOWEVER MOST
OF THIS MOISTURE/CONVERGENCE/ENERGY STAYS INTO CENTRAL AND EASTERN
KANSAS AND EASTERN NEBRASKA SO LIMITED RAIN CHANCES TO THE FAR
EASTERN COUNTIES IN THE FORECAST AREA. THIS WAS SUPPORTED BY THE
23.21Z AND 24.03Z SREF RUNS WHICH DID NOT HAVE ANY PROBABILITIES
OF RAINFALL AMOUNTS OVER 0.25 INCH IN THE LOCAL FORECAST AREA.
CONCERNING THE NORTHERN SYSTEM...THE SHORTWAVE WILL BE OVER
SOUTHERN SASKATCHEWAN AT 25.00Z. THIS WILL BRING THE COLD FRONT
INTO THE WESTERN DAKOTAS AND THE NEBRASKA PANHANDLE. KEPT THE
FORECAST DRY OVERNIGHT AS THE FRONT PUSHES EAST...WITH THE
STRONGEST FORCING STAYING WELL TO THE NORTH. THERE IS INDICATIONS
OF SOME MOISTURE CONVERGENCE ALONG THE FRONT OVERNIGHT...SO
WOULDN/T BE SURPRISED TO SEE AN ISOLATED STORM DEVELOP...BUT AGAIN
DIDN/T HAVE THE CONFIDENCE TO ADD CHANCES IN AT THIS POINT.
THE FRONT PUSHES THROUGH THE FORECAST AREA ON SATURDAY...BRINGING
DRIER AND COOLER AIR BEHIND IT. CONVECTION SHOULD CONTINUE
THROUGH THE DAY ALONG THE FRONT. WITH MODELS BEING IN GOOD
AGREEMENT WITH PUSHING THE RAIN EAST OF THE FORECAST AREA...DID
TREND THE FORECAST THAT DIRECTION. DID LEAVE IN SOME SLIGHT
CHANCES IN THE NORTHEASTERN ZONES TO ACCOUNT FOR SLOWER FRONTAL
MOVEMENT OR LINGERING ACTIVITY. DID KEEP TEMPERATURES AHEAD OF THE
FRONT LOWER AS THE FRONT WILL PUSH THROUGH BEFORE AFTERNOON
HEATING SETS IN...AS WELL AS THE THOUGHT THAT THERE MAY AGAIN BE A
BATCH OF STRATUS IN THESE AREAS IN THE MORNING. ALTHOUGH
TEMPERATURES WILL BE COOLER ON SATURDAY...WITH HIGHS IN THE
80S...DEWPOINTS LOOK TO DROP INTO THE 30S BEHIND THE FRONT. THIS
WILL DROP RELATIVE HUMIDITY TO AROUND 20 PERCENT IN THE AFTERNOON.
ALSO EXPECTING BREEZY NORTHERLY WINDS BEHIND THE FRONT. ALTHOUGH
DON/T ANTICIPATE NEEDING HEADLINES FOR FIRE WEATHER...WILL NEED TO
KEEP THIS IN MIND AS FIRE WEATHER CONDITIONS WILL BE NEAR
CRITICAL.
SATURDAY NIGHT THROUGH SUNDAY NIGHT SHOULD BE FAIRLY QUIET AS
UPPER LEVEL RIDGING STARTS TO BUILD IN AS THE SHORTWAVES EXIT TO
THE EAST. SKIES SHOULD CLEAR THROUGH THE PERIOD WITH HIGH PRESSURE
SETTLING IN. COULD SEE TEMPERATURES DROP DOWN INTO THE 50S OVER
MUCH OF THE AREA SATURDAY NIGHT...DUE TO GOOD RADIATIONAL COOLING.
.LONG TERM...MONDAY THROUGH THURSDAY
NO BIG CONCERNS TO DEAL WITH THROUGH THIS PORTION OF THE FORECAST.
THE UPPER LEVEL RIDGE BUILDS IN...SO ANOTHER WARMING TREND IS
EXPECTED WITH HIGHS IN THE UPPER 80S AND 90S THROUGH MUCH OF THE
WEEK. NO GOOD CHANCES FOR RAIN EXIST...ALTHOUGH THERE MAY BE
STORMS TOPPING THE RIDGE TO IMPACT NORTHERN NEBRASKA. WITH VERY
LITTLE CONFIDENCE ON WHEN AND WHERE THESE STORMS WILL DEVELOP KEPT
THE FORECAST DRY THROUGHOUT THIS TIME. WITH THE DRY
CONDITIONS...AND WITH A LACK OF MOISTURE BEING BROUGHT
NORTH...WILL EXPECT LARGE TEMPERATURE SWINGS SO ALTHOUGH HIGHS
WILL BE IN THE 90S...STILL LOOKING AT LOWS IN THE 50S AND LOW 60S
MOST NIGHTS.
EYES CONTINUE TO WATCH TROPICAL STORM ISAAC...WHICH IS WELL OUT IN
THE CARIBBEAN CURRENTLY. LONG TERM MODELS COMING INTO MORE
AGREEMENT IN SOLUTIONS...BRINGING IT ONSHORE NEAR MOBILE ALABAMA
THEN PUSHING NORTHWARD INTO THE OHIO RIVER VALLEY BEFORE BEING
CAUGHT UP IN THE FLOW AND SHUNTED EAST. THIS WOULD PROVIDE NO HELP
TO THE LOCAL AREA IN TERMS OF MOISTURE UNFORTUNATELY. THIS IS ALL
TO OCCUR NEXT WEEKEND AND THE NEXT WEEK SO THINGS COULD CERTAINLY
CHANGE BEFORE THEN AND WILL BE WATCHING TO SEE IF THERE MAY BE ANY
IMPACT LOCALLY FROM THIS STORM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT/LONG TERM...BROOKS
AVIATION...CLB
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
603 AM MDT FRI AUG 24 2012
.AVIATION...
UPPER LEVEL LOW TO TRACK ACROSS SOUTHERN COLORADO TODAY...
SUPPORTING A WEST TO EAST MOIST FLOW ACROSS NORTHERN AND WESTERN
ZONES. SOME PATCHY LOW CLOUDS WILL DEVELOP EAST OF THE CENTRAL
MOUNTAINS THIS MORNING...GENERALLY FROM KCQC SOUTH TO NEAR
KSRR. MID AND HIGH LEVEL CLOUDS ALREADY IN PLACE WILL GIVE WAY TO
ISOLATED TO SCATTERED THUNDERSTORMS AND SHOWERS MAINLY OVER THE
HIGHER TERRAIN...WITH THE NORTH CENTRAL MOUNTAINS POTENTIALLY
SEEING MORE ACTIVITY...MAINLY FROM 17Z THROUGH 03Z. THUNDERSTORMS
WILL RESULT IN MFVR CIGS AND VISIBILITIES IN RAIN OR HEAVY RAIN AT
TIMES AS WELL AS SOME MOUNTAIN TOP OBSCURATIONS. MOSTLY MID LEVEL
CLOUDS TO PERSIST AFTER 03Z THROUGH REMAINDER OF PERIOD.
05
&&
.PREV DISCUSSION...300 AM MDT FRI AUG 24 2012...
UPPER LOW CIRCULATION NEAR KFMN EARLY THIS MORNING. RUC OPENS IT UP
BY MIDDAY WHILE FORECAST POSITION WILL BE OVER NRN MTS. GFS SEEMS TO
MOVE THE TROUGH A LITTLE FASTER THAN 24 HOURS AGO WHILE NAM
INDICATES SOME HANG BACK ENERGY WHICH RETARDS EASTWARD PROGRESS AND
THEREFORE THE TROUGHS EXIT UNTIL LATE SATURDAY AFTERNOON.
NONETHELESS...MOISTURE WILL REMAIN IN PLACE TODAY AND TONIGHT
ESPECIALLY AOB H5 WHILE MODELS AND SATELLITE IMAGERY INDICATE DRYING
IN THE UPPER LEVELS OF THE ATMOSPHERE. UPSLOPE WINDS SHOULD FAVOR
CONVECTION OVER THE WESTERN/NORTHERN MOUNTAINS TODAY AND WITH WIND
SHIFT IN THE NORTHEAST...THE FOCUS FOR RAIN MAY LIKELY SHIFT INTO
THAT REGION LATER THIS AFTERNOON/EVENING WITH THE UPPER TROUGH
NEARING. TEMPERATURES TODAY STILL A BIT ON THE LOWER SIDE OF AVERAGE
CENTRAL AND WEST...BUT A LITTLE ABOVE IN THE EAST.
SATURDAY WILL BE A TRANSITION DAY AS THE TROUGH EXITS AND AN
EASTERLY LOW LEVEL GRADIENT SETS UP OVER EASTERN NEW MEXICO. THERE
MAY BE SOME POTENTIAL FOR AN EAST WIND INTO THE RGV SATURDAY
NIGHT...BUT THIS APPEARS MORE LIKELY SUNDAY/SUNDAY NIGHT AS THE
UPPER HIGH CENTER SETS UP SHOP OVER NRN NM/SRN CO. WHILE LOW LEVEL
MOISTURE MAY START TO DRY/MIX OUT IN THE FAR NORTHWEST...THE
BOUNDARY LAYER WINDS SHOULD KEEP DEWPOINTS FROM CRATERING IN THE
EAST. TEMPERATURE WISE...MOST AREAS SHOULD BE A FEW DEGREES WARMER
THAN AVERAGE DURING THE DAY BY MONDAY...WHILE MINS GENERALLY STAY
ABOVE NORMAL FOR THE NEXT SEVERAL DAYS.
BY MID TO LATE NEXT WEEK...FORECAST MODELS CONTINUE TO HAVE TROUBLE
RESOLVING THE STRENGTH OF THE UPPER HIGH AND THE LOCATION AND
STRENGTH OF THE WESTERLIES OVER THE NORTHERN/CENTRAL TIER OF THE
WESTERN U.S. CONFIDENCE NOT ALL THAT GREAT IN ONE SCENARIO VS
ANOTHER SO GENERIC AFTERNOON/EVENING SHOWERS AND STORMS FAVORING THE
HIGHER TERRAIN SEEMS BEST FOR NOW.
.FIRE WEATHER...
WEAK UPPER LEVEL DISTURBANCE IS CURRENTLY CENTERED NEAR THE FOUR
CORNERS WITH MID AND UPPER LEVEL DRY SLOT WORKING INTO CENTRAL NEW
MEXICO. SURFACE DEWPOINTS DECREASING AS WELL ESPECIALLY WEST AND
CENTRAL ZONES. THE UPPER WAVE WILL MOVE TO THE EAST DURING THE DAY
WITH WETTING RAIN FAVORING THE WESTERN AND NORTHERN ZONES WITH
BREEZY WEST WINDS DEVELOPING THIS AFTERNOON ACROSS THE EAST CENTRAL
PLAINS. TEMPS WARM A BIT MOST ZONES WITH SUBSTANTIAL DECREASES IN
AFTERNOON RH VALUES.
HIGH PRESSURE BUILDS IN THE WAKE OF THE UPPER LEVEL DISTURBANCE WITH
A RIDGE AXIS NEAR THE FOUR CORNERS BY MID DAY SATURDAY SUPPORTING
ADDITIONAL WARMING AND DRYING ACROSS WESTERN AND NORTHCENTRAL ZONES.
SUFFICIENT MOISTURE PERSISTS AT THE SURFACE TO SUPPORT SCATTERED
THUNDERSTORMS OVER THE HIGHER TERRAIN WITH ISOLATED COVERAGE
ELSEWHERE. A BACK DOOR FRONT WILL PUSH INTO THE NORTHEAST LATE ON
SATURDAY AND THROUGH THE EAST PLAINS ON SUNDAY AS THE UPPER HIGH
CENTERS OVER NEW MEXICO. MODERATE GAP WINDS WERE ADDED TO THE GRIDS
FOR SATURDAY NIGHT...AND DEPENDING ON THE STRENGTH OF THE EAST WINDS
SURFACE MOISTURE INCREASES COULD MAKE IT TO THE CONTINENTAL DIVIDE.
WETTING RAINS ON SUNDAY LOOK TO FAVOR THE CENTRAL HIGH TERRAIN AND
ADJACENT EAST SLOPES WITH AN UPTICK IN COVERAGE OVER THE WESTERN
TERRAIN.
MODELS GENERALLY AGREE ON BUILDING THE UPPER HIGH EARLY IN THE WORK
WEEK WITH POSSIBLY A SLIGHT SHIFT TO THE EAST. A MONSOON PLUME WORKS
AROUND THE WESTERN EDGE OF THE HIGH...BUT THE FOCUS REMAINS OVER
MEXICO. THE EASTERN PLAINS LOOK TO BE DRIER WITH PRECIPITATION
SHIFTING TO THE WEST. THE RIDGE LOOKS TO WEAKER LATER IN THE WEEK
WITH A GENERAL DECREASE IN RELATIVE HUMIDITIES AND WETTING RAIN MOST
LOCATIONS.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
627 AM CDT FRI AUG 24 2012
.DISCUSSION...
LOOK FOR VFR CONDITIONS TO DOMINATE WEST CENTRAL TEXAS FOR THE
NEXT 24 HOURS. AVIATION BELOW HAS DETAILS.
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS MAY DEVELOP ACROSS WEST CENTRAL TEXAS
TODAY AND TONIGHT. A TROUGH OF LOW PRESSURE ALOFT...WILL CONTINUE
TO MOVE SLOWLY EAST INTO THE CENTRAL TEXAS TODAY AND TONIGHT. THIS
FEATURE MAY PROVIDE THE NECESSARY UPPER DYNAMICS TO INITIATE
SHOWERS AND THUNDERSTORMS. OTHERWISE...PLAN FOR GUSTY SOUTH
SURFACE WINDS ACROSS WEST CENTRAL TEXAS TODAY...ESPECIALLY ACROSS
THE BIG COUNTRY AND CONCHO VALLEY. TONIGHT...SURFACE WINDS WILL
DIMINISH TO AROUND 10 KNOTS OR LESS.
HUBER
&&
.PREV DISCUSSION... /ISSUED 328 AM CDT FRI AUG 24 2012/
SHORT TERM...
RAIN CHANCES FOR MOST OF WEST CENTRAL TEXAS LOOK SOMEWHAT PROMISING
FOR THE NEXT 24 HOURS. MODELS INDICATE A SHORT WAVE TROUGH OF LOW
PRESSURE WILL PROVIDE SOME UPPER-LEVEL DYNAMICS. MODELS SHOW THIS
FEATURE BEST AT 700 MB. ALTHOUGH THE NAM AND THE RUC (HIGH
RESOLUTION RAPID REFRESH) INDICATE SOME DECLINE IN CONVECTIVE
COVERAGE BETWEEN NOW AND 18Z...I DECIDED TO INCLUDE THE FIRST 6
HOURS OF THE TODAY PERIOD WITH SLIGHT CHANCE TO CHANCE POPS ACROSS
THE BOARD. IN ADDITION...MODELS CONTINUE AT LEASE A SLIGHT CHANCE
THROUGH TONIGHT. ALSO...HPC QPF GRIDS FOR THE FIRST 24 HOURS LOOK
REASONABLE.
AS FOR TEMPERATURES...NUMBERS CLOSE TO MEX MOS LOOK ON TRACK FOR
TODAY AND TONIGHT. LIMITED SUNSHINE AND NORTHWEST FLOW ALOFT WILL
HOLD AFTERNOON HIGHS TODAY MAINLY IN THE LOWER TO MID 90S. OVERNIGHT
LOWS TONIGHT WILL BE MAINLY IN THE LOWER TO MID 70S.
HUBER
LONG TERM...
BY SATURDAY MORNING THE MID LEVEL TROUGH AXIS WILL STRETCH
NORTHEASTWARD FROM SOUTHERN NEW MEXICO ACROSS THE NORTHERN
PANHANDLE AND INTO THE CENTRAL PLAINS. THE SLOW MOVING UPPER
TROUGH AXIS WILL FINALLY MOVE EAST OF THE FORECAST AREA BY LATE
SUNDAY. UNTIL THEN...ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
POSSIBLE OVER MUCH OF THE FORECAST AREA...FAVORING THE WESTERN AND
NORTHERN CWA.
WITH AN INCREASE IN CLOUD COVER...AFTERNOON HIGHS WILL REMAIN IN
THE LOW TO MID 90S THROUGH THE WEEKEND. MORNING LOWS WILL BE IN
THE LOWER 70S.
UPPER LEVEL HILL PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF
THE DEPARTING UPPER LEVEL TROUGH INTO THE FIRST OF THE COMING
WEEK. THE CENTER OF THE UPPER LEVEL HIGH WILL SETTLE OVER NEW
MEXICO. WITH THE UPPER RIDGE AND SUNNY SKIES DOMINATING THE AREA
AT LEAST THROUGH THE MIDDLE OF NEXT WEEK...AFTERNOON TEMPERATURES
WILL EDGE A LITTLE HIGHER TO THE MID TO UPPER 90S. LOOKING FOR A
DRY FORECAST FOR THE REMAINDER OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 95 73 94 72 / 20 20 20 20 20
SAN ANGELO 73 95 73 95 72 / 20 20 20 10 10
JUNCTION 74 92 71 93 70 / 10 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
634 AM CDT FRI AUG 24 2012
.SHORT TERM...THROUGH SUNDAY
239 AM CDT FRI AUG 24 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS MORNING SHOWS AN AREA OF LOW PRESSURE OVER
SOUTHEAST MONTANA. A WEAK WARM FRONT EXTENDS FROM THE LOW ACROSS
CENTRAL MINNESOTA INTO NORTHERN WISCONSIN. REGIONAL RADARS WERE
SHOWING A LINE OF SHOWERS AND THUNDERSTORMS FROM LAKE SUPERIOR
INTO NORTHEAST IOWA.
THE ONGOING CONVECTION WAS BEING FUELED BY A SHORT WAVE TROUGH
MOVING ACROSS MINNESOTA. THE 24.05Z RAP INDICATES THIS WAVE WILL
MOVE EAST INTO WISCONSIN IN THE PRE-DAWN HOURS AND THEN AWAY FROM
THE REGION AFTER SUNRISE. THE ACTIVITY CURRENTLY LOOKS TO BE ON
THE EASTERN EDGE OF THE MU CAPE GRADIENT AS THIS QUICKLY DROPS TO
250 J/KG OR LESS ACROSS WESTERN INTO CENTRAL WISCONSIN. BOTH THE
24.00Z HIRES ARW AND NMM SUGGEST THE ACTIVITY IS THE STRONGEST NOW
AND WILL DISSIPATE THROUGH THE REMAINDER OF THE NIGHT AS IT MOVES
OUT OF THE CAPE AXIS. WILL MONITOR THE LATEST RADAR TRENDS AND
MAKE ADJUSTMENTS AS NEEDED BUT CURRENTLY FEEL THE BEST CHANCE OF
ANY ACTIVITY STILL TO BE ONGOING AFTER 12Z IS ACROSS NORTH CENTRAL
WISCONSIN WHERE THE CAPE IS A LITTLE BETTER AND THE MOISTURE
TRANSPORT SHOULD BE THE STRONGEST. FOR THE AFTERNOON...THE 24.00Z
NAM AND GFS INDICATE ANOTHER WEAK SHORT WAVE TROUGH WILL TRACK
ACROSS NORTHERN MINNESOTA TOWARD LAKE SUPERIOR. THIS WAVE WILL
PRODUCE ONLY SOME WEAK VORTICITY ADVECTION IN THE 500-300 MB LAYER
NORTH OF THE AREA. SOME WEAK ISENTROPIC UP GLIDE WILL CONTINUE
OVER THE REMAINS OF THE WARM FRONT WITH THE NAM SHOWING AROUND 2
UBAR/S ACROSS NORTHWEST INTO CENTRAL WISCONSIN. THIS MAY BE ENOUGH
TO GENERATE SOME ADDITIONAL WIDELY SCATTERED CONVECTION AND WILL
KEEP THE 20 PERCENT CHANCES IN THE I94 CORRIDOR.
AFTER TODAY...THE NEXT CHANCE OF RAIN WILL BE SATURDAY THROUGH
SUNDAY. A LARGE UPPER LEVEL LOW OVER WESTERN CANADA WILL TRACK
EAST WHILE REMAINING NORTH OF THE BORDER. AS IT DOES...A WEAK
UPPER LEVEL LOW OVER THE FOUR CORNERS WILL CONTINUE TO WEAKEN AND
BECOME AN OPEN WAVE WHILE BEING PULLED NORTHEAST AHEAD OF THE
CANADIAN UPPER LEVEL LOW. THE MODELS INDICATE THE REMAINS OF THE
FOUR CORNERS UPPER LEVEL LOW WILL COME THROUGH IN A COUPLE OF
PIECES WITH THE FIRST MOVING ACROSS THE REGION SATURDAY AND THE
SECOND SATURDAY NIGHT AND SUNDAY. NONE OF THE MODELS PRODUCE MUCH
VORTICITY ADVECTION WITH THE NAM AND 23.12Z ECMWF SHOWING 2 PVU/S
OR LESS WHILE THE 24.00Z GFS IS A LITTLE STRONGER SHOWING UP TO 4
PVU/S. A WEAK COLD FRONT OR TROUGH OF LOW PRESSURE SHOULD MOVE
SLOWLY ACROSS THE AREA WITH THE SHORT WAVE TROUGHS. SOME WEAK
FRONTOGENESIS IN THE 1000-700 MB LAYER SHOULD OCCUR WITH THIS
FEATURE SATURDAY AFTERNOON AND THERE SHOULD BE SOME PERSISTENT UP
GLIDE OF 1 TO 3 UBAR/S ON THE 310K SURFACE UNTIL THIS FEATURE
MOVES THROUGH THE AREA. SINCE THE FORCING WITH THESE WAVES IS NOT
THAT STRONG EXPECTING MAINLY SCATTERED CONVECTION TO OCCUR
SATURDAY AS THE LEAD WAVE COMES IN. THE COVERAGE COULD BE A LITTLE
BIT BETTER SATURDAY NIGHT ACROSS THE SOUTH AHEAD OF THE SECOND
WAVE WHERE THE VORTICITY ADVECTION COULD BE A LITTLE BIT STRONGER.
THE SEVERE POTENTIAL LOOKS PRETTY LOW SATURDAY AND SATURDAY NIGHT
WITH ML CAPES OF 500 J/KG OR LESS EXPECTED AND THE 0-6 KM SHEAR IS
ONLY AROUND 25 KNOTS.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
239 AM CDT FRI AUG 24 2012
ONCE THIS SYSTEMS MOVES OUT...A LARGE AREA OF HIGH PRESSURE WILL
BUILD IN OVER THE UPPER MIDWEST AND SHOULD REMAIN THROUGH MUCH OF
THE PERIOD. TOWARD THE END OF THE PERIOD...THE GFS IS TRYING TO
BRING A SHORT WAVE TROUGH AND UPPER LEVEL LOW THROUGH THE TOP OF
THE UPPER LEVEL RIDGE AND ACROSS SOUTHERN CANADA AND THE UPPER
MIDWEST. THE 24.00Z ECMWF MAINTAINS THE UPPER LEVEL RIDGE OVER THE
AREA WITH ANY TROUGHING OVER SOUTHWEST CANADA INTO THE NORTHERN
ROCKIES. WILL TREND TOWARD THE ECMWF SOLUTION AND KEEP THE ENTIRE
PERIOD DRY.
&&
.AVIATION...TODAY AND TONIGHT
633 AM CDT FRI AUG 24 2012
A SHORT WAVE TROUGH CONTINUES TO PRODUCE A BAND OF SHOWERS AND
THUNDERSTORMS SOUTHEAST OF A CHARLES CITY IOWA TO JUMP RIVER
WISCONSIN LINE. THIS PRECIPITATION WILL MOVE OUT OF KLSE BY
24.13Z. A FEW MORE SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND
NORTH OF THE INTERSTATE 90 CORRIDOR IN WISCONSIN THIS AFTERNOON.
HOWEVER THE CONFIDENCE IS SO SMALL THAT THEY WERE NOT INCLUDED IN
THE KLSE TAF.
FOR TONIGHT...BOTH TAF SITES WILL BE WELL INTO THE WARM SECTOR OF
AN APPROACHING LOW PRESSURE SYSTEM FROM THE NORTHERN PLAINS. AS A
RESULT...SKIES SHOULD BE MAINLY CLEAR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
239 AM CDT FRI AUG 24 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE
AREA FORECAST DISCUSSION...AMENDED
NWS ALBANY NY
440 PM EDT FRI AUG 24 2012
.SYNOPSIS...
HIGH PRESSURE AT THE SURFACE WILL REMAIN ACROSS OUR REGION THROUGH
THE WEEKEND. AN UPPER LEVEL DISTURBANCE WILL SLIDE JUST SOUTH OF NEW
YORK STATE ON SATURDAY BUT ITS INFLUENCE COULD RESULT IN WIDELY
SCATTERED AFTERNOON SHOWERS OR THUNDERSTORMS...MAINLY ACROSS THE
HIGHER TERRAIN. A STRAY SHOWER CANNOT BE RULED ON SUNDAY BUT THE
MAJORITY OF BOTH WEEKEND DAYS WILL BE DRY WARM AND SOMEWHAT HUMID
WITH AT PARTIAL SUNSHINE.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 430 PM...NOT NEARLY AS MANY CU TODAY AS YESTERDAY. DEWPOINTS
HAVE DROPPED WELL DOWN INTO THE 50S AS MID LEVEL DRY AIR HAS WORKED
INTO THE REGION AND MIXED DOWNWARD ALTHOUGH SURFACE WINDS WERE
LIGHT. TEMPERATURES WELL QUITE WARM...WELL INTO THE 80S BUT WITH THE
LOWER DEWPOINTS...THE HEAT INDEX WAS AT OR EVEN A COUPLE OF POINTS
LOWER THAN THE ACTUAL AMBIENT TEMPERATURE.
THE LATEST EXPERIMENTAL HRRR INDICATED MODERATE TO TOWERING CU COULD
ONCE AGAIN BUILD ACROSS THE TACONICS AND POINTS EAST. HOWEVER
TODAY...DEWPOINTS WERE DEFINITELY ABOUT 5 DEGREES LOWER THAN
YESTERDAY SO RIGHT NOW...FEEL NOTHING SHOULD GROW TALL FOR ANY
SHOWER LET ALONE THUNDERSTORM ACTIVITY.
ANY AND ALL CU WILL DIMINISH AROUND SUNSET.
ANOTHER FEATURE ON THE H20 LOOP WAS AN UPPER LEVEL LOW PRESSURE OVER
THE LOWER MID ATLANTIC (VA/NC). THIS FEATURE WAS TRIGGERING
THUNDERSTORMS IN SE NC. THIS FEATURE LOOKS TO LIFT A LITTLE FURTHER
NORTHWARD IN THE NEXT 24 HOURS...BUT NOW APPEARS THE CENTER OF THE
UPPER LEVEL FEATURE (WITH SLOW COLDER AIR AND CYCLONIC FLOW) WILL
STAY MAINLY SOUTH OF OUR REGION.
THIS FEATURE WAS ATTEMPTING TO PUSH HIGH AND MID LEVEL CLOUDS INTO
OUR REGION...BUT SO ONLY THE THINNER CI HAVE INTO THE REGION. THE
CANADIAN ASTRONOMICAL CLOUD FORECAST DOES INDICATE THICKER CLOUDS
MOVING MAINLY INTO OUR SOUTHERN REGION LATER TONIGHT AND THINNER
ONES FURTHER NORTH.
DECIDED TO PLACE PATCHY FOG IN THE GRIDS AS DEWPOINTS SHOULD CLIMB
BACK TO AROUND 60 WITH LIGHT WIND SO EVEN WITH SOME HIGH CLOUDS...A
LITTLE FOG COULD FORM IN THOSE FOG PRONE AREAS.
LOOK FOR LOW TEMPERATURES OVERNIGHT AROUND 60 IN THE CAPITAL
REGION...SOUTHWARD THROUGH THE HUDSON VALLEY. MOST OTHER PLACES WILL
BE IN THE MID TO UPPER 50S...EXCEPT LOWER 50S ACROSS PORTIONS OF THE
ADIRONDACK PARK.
THE AFOREMENTIONED UPPER LEVEL SYSTEM...WHILE NOT QUITE MAKING IT
INTO REGION...MIGHT NEVERTHELESS BE JUST ENOUGH OF A FOCUS TO
TRIGGER A WIDELY SCATTERED SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS MAINLY THE ELEVATED TERRAIN OF OUR AREA. MODELS INDICATE
MUCAPES CREEP UP TO ABOUT 1000 J/KG AND ANY MID LEVEL CAP SHOULD BE
DIMINISHED. PWATS CREEP UP A LITTLE AS OUR AREA WILL SEE A WEAK SSE
FLOW ADVECTING A LITTLE MORE MOISTURE INTO OUR REGION.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
THE AFOREMENTIONED UPPER LEVEL SYSTEM...WHILE NOT QUITE MAKING IT
INTO REGION...MIGHT NEVERTHELESS BE JUST ENOUGH OF A FOCUS TO
TRIGGER A WIDELY SCATTERED SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS MAINLY THE ELEVATED TERRAIN OF OUR AREA. MODELS INDICATE
MUCAPES CREEP UP TO ABOUT 1000 J/KG AND ANY MID LEVEL CAP SHOULD BE
DIMINISHED. PWATS CREEP UP A LITTLE AS OUR AREA WILL SEE A WEAK SSE
FLOW ADVECTING A LITTLE MORE MOISTURE INTO OUR REGION AS A WEAK
THETA-E RIDGE SETS UP.
THE UPPER LEVEL FEATURE LOOKS TO MOVE TO SOUTHEAST LATER SATURDAY
NIGHT...REPLACED BY A RIDGE OF HIGH LATE SATURDAY EVENING THROUGH
SUNDAY NIGHT.
ANY THUNDERSTORM ACTIVITY SHOULD DIMINISH FAIRLY QUICKLY SATURDAY
EVENING LEAVING US WITH ANY PARTLY CLOUDY SOMEWHAT MUGGY NIGHT WITH
PATCHY VALLEY FOG BY EARLY SUNDAY MORNING.
SUNDAY LOOKS LIKE A MAINLY SUNNY WARM DAY WITH A TOUCH LESS HUMIDITY
THAN SATURDAY. A STRAY SHOWER OR THUNDERSTORM CANNOT BE ENTIRELY
RULED OUT OVER THE HIGHER TERRAIN...WE LEFT 20 POPS IN AREAS WITH
MEAN ELEVATIONS OF 1000 FEET OR HIGHER.
SUNDAY NIGHT...HIGH PRESSURE BEGINS TO DRIFT OFFSHORE. A WEAK
SOUTHERLY FLOW WILL SEND MORE HUMIDITY AND POSSIBLY SOME STRATUS OUR
WAY. AT THIS POINT IT LOOKS TO BE RAINFREE.
THEN ON MONDAY A PRE-FRONTAL TROUGH MIGHT BE THE FOCUS FOR SOME
CONVECTION OUT AHEAD OF COLD FRONT (THAT IS EXPECTED TO ARRIVE
MONDAY NIGHT OR EARLY TUESDAY PLEASE REFER TO THE EXTENDED PORTION
OF OUR DISCUSSION FOR MORE ON THAT FEATURE). FOR NOW...ASSIGN A 30
POP FOR AFTERNOON SHOWERS AND THUNDERSTORMS. IT IS TOO EARLY TO
REALLY ACCESS HOW STRONG (OR NOT STRONG) THEY COULD GET.
TEMPERATURES THROUGH THE SHORT TERM WILL REMAIN A LITTLE ABOVE
NORMAL...WITH HIGH TEMPERATURES GENERALLY WELL INTO THE 80S BY DAY
(CLOSER TO 80 OVER THE MOUNTAINS)...AND LOWS IN THE UPPER 50S TO MID
60S AT NIGHT.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
GOOD CONSENSUS IN LONG RANGE GUIDANCE AND ENSEMBLES THAT A COLD
FRONT TRACKS THROUGH THE REGION MONDAY NIGHT...PERHAPS LINGERING
INTO TUESDAY...DEPENDING ON THE ULTIMATE TIMING OF THE FRONT. SOME
DIVERGENCE IN THE GUIDANCE AND ENSEMBLES BEYOND TUESDAY...SOME OF
THE DIVERGENCE ATTRIBUTED TO FEATURES RELATED TO WHATEVER FORM ISAAC
IS IN AND WHERE IT TRACKS...WHETHER IT IS OVER LAND...WATER...STRONG
ENOUGH TO STRENGTHEN UPPER RIDGING AROUND IT...OR WEAK AND NEARLY
STATIONARY OVER THE SOUTHEAST U.S. OR IF IT GETS CAUGHT IN ANY
STEERING FLOW THAT WOULD TRACK ITS REMNANTS TOWARD THE NORTHEASTERN
U.S. OR EVEN OFFSHORE. BASICALLY...THERE ARE STILL A LOT OF
POSSIBILITIES WITH ISAAC...AND DEPENDING ON ITS POSITION AND
STRENGTH...COULD INFLUENCE HOW MUCH COLD AIR SINKS SOUTH OUT OF
CANADA...OR LACK THEREOF...INTO OUR REGION TUESDAY THROUGH THURSDAY.
THE GENERAL CONSENSUS...REGARDLESS OF THE TEMPERATURES...IS THAT THE
WEATHER SHOULD BE DRY TUESDAY THROUGH THURSDAY...MAYBE EVEN
INCLUDING FRIDAY...DEPENDING ON THE TRACK OF WHAT IS LEFT OF ISAAC
AND DEPENDING ON TIMING AND STRENGTH OF ANOTHER COLD FRONT THAT
COULD SINK SOUTH OUT OF CANADA THE END OF NEXT WEEK. OFFICIAL
FORECAST OF REMNANTS OF ISAAC STALLING IN THE SE U.S. THROUGH FRIDAY
WITH A POTENTIAL COLD FRONT WELL NORTHWEST IN THE CENTRAL GREAT
LAKES FRIDAY MORNING. FUTURE DATA AND GUIDANCE THROUGH THIS WEEKEND
MAY FORCE SOME PERIODIC ADJUSTMENTS TO FORECASTS FOR TUESDAY THROUGH
FRIDAY.
KEEPING TUESDAY NIGHT THROUGH FRIDAY DRY BASED ON HPC FORECAST OF
REMNANTS STALLING IN THE SOUTHEASTERN U.S....UNTIL THE FINER DETAILS
OF ISAAC REMNANTS AND ANY POTENTIAL COLD FRONTS LATE NEXT WEEK ARE
KNOWN. ACKNOWLEDGING A COOLDOWN FOR TUESDAY THROUGH THURSDAY...BUT
BEING A LITTLE CAUTIOUS ABOUT HOW MUCH OF A COOLDOWN...AGAIN...UNTIL
SOME OF THE FINE DETAILS EMERGE ON THE OVERALL UPPER PATTERN FOR
NEXT WEEK.
SO...HIGHS IN THE LOWER 70S HIGHER ELEVATIONS TO LOWER 80S IN THE
VALLEYS TUESDAY. HIGHS WEDNESDAY AND THURSDAY COOLING INTO THE UPPER
60S HIGHER ELEVATIONS TO UPPER 70S TO NEAR 80 IN THE VALLEYS. HIGH
TEMPERATURES FRIDAY BACK UP TO THE MID 70S HIGHER ELEVATIONS TO
LOWER TO MID 80S VALLEYS.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
NO AVIATION WEATHER RELATED PROBLEMS ARE EXPECTED THROUGH THIS
EVENING. VFR CONDITIONS WILL PREVAIL. ANY SCT FLAT BASED CU WILL
DIMINISH BY SUNSET.
LATER THIS EVENING.. .RADIATION BR/FG WILL LIKELY DEVELOP AGAIN AT
KGFL/KPSF WITH ASSOCIATED MVFR/IFR CONDITIONS. WILL MENTION MVFR
VSBY AT KPOU WITH BR SIMILAR TO WHAT HAS OCCURRED THE PAST FEW
MORNINGS. THE FOG SHOULD BURN OFF AT ALL SITES BY 12Z-13Z AND VFR
CONDITIONS SHOULD PREVAIL AFTERWARD.
WINDS SHOULD BE LIGHT AND VARIABLE THROUGH TONIGHT...THEN BECOME
LIGHT SOUTH TO SOUTHEAST TOMORROW AT 6 KT OR LESS.
OUTLOOK...
SAT-SUN...VFR...ISOLD -SHRA/-TSRA.
MON...VFR...ISOLD-SCT SHRA/TSRA.
TUE...VFR/MVFR SCT -SHRA WITH ISOLD -TSRA.
WED...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER RELATED ISSUES THROUGH SUNDAY WITH A
SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM EACH AFTERNOON. MANY
PLACES WILL NOT RECEIVE ANY RAINFALL.
RELATIVE HUMIDITY WILL RECOVER TO BETWEEN 85 AND 100 PERCENT
OVERNIGHT WITH HEAVY DEW FORMATION...AND DROP TO 45 TO 60 PERCENT ON
SATURDAY...35 TO 50 PERCENT ON SUNDAY.
THE WIND WILL BE LIGHT VARIABLE GENERALLY UNDER 10 MPH.
THE NEXT CHANCE FOR MORE NUMEROUS SHOWERS LOOKS TO BE LATE MONDAY.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS.
DRY WEATHER IS EXPECTED TONIGHT AND AGAIN SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE BEST CHANCES FOR PRECIPITATION WILL BE SATURDAY
AFTERNOON INTO EARLY SATURDAY EVENING AS AN UPPER LEVEL DISTURBANCE
SLIDING TO OUR SOUTH PRODUCES WIDELY SCATTERED TO SCATTERED SHOWERS
ALONG WITH A FEW EMBEDDED THUNDERSTORMS. THE PRECIPITATION IS
EXPECTED TO BE MAINLY CONFINED TO THE HIGHER ELEVATIONS. THERE WILL
BE ANOTHER CHANCE OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS MONDAY
AFTERNOON INTO TUESDAY ALONG AND AHEAD OF A COLD FRONT MOVING
THROUGH THE REGION. TOTAL AVERAGE RIVER BASIN QPF AMOUNTS THROUGH
TUESDAY ARE GENERALLY EXPECTED TO BE LESS THAN A QUARTER OF AN
INCH...ALTHOUGH LOCALIZED HIGHER AMOUNTS ARE POSSIBLE IN
THUNDERSTORMS. THIS PRECIPITATION IS EXPECTED TO HAVE LITTLE IF ANY
IMPACT ON STREAMS AND RIVERS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV
NEAR TERM...HWJIV
SHORT TERM...HWJIV
LONG TERM...NAS
AVIATION...NAS
FIRE WEATHER...HWJIV
HYDROLOGY...HWJIV/FRUGIS/11
INCLUDES THE LONG TERM DISCUSSION.
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
542 PM CDT FRI AUG 24 2012
.DISCUSSION...
324 PM CDT
TODAY THROUGH SATURDAY NIGHT...
AN UPPER LEVEL DISTURBANCE IS SLOWLY PASSING THROUGH NORTHERN
WISCONSIN AND WILL CONTINUE EASTWARD THROUGH THE NORTHERN GREAT
LAKES THIS EVENING. SOME OF THE SHORT TERM MODELS INDICATE
SCATTERED SHOWERS WILL DEVELOP ACROSS NORTHERN ILLINOIS...BUT WILL
CONTINUE WITH A DRY FORECAST THIS AFTERNOON. LATEST RAP ANALYSIS
INDICATES AMPLE CAPE AND LOW LEVEL LAPSE RATES NEAR DRY
ADIABATIC...HOWEVER SUSPECTING THE RAP ANALYSIS MAY BE OVER
ESTIMATING CAPE VALUES. ALSO TOOK INTO CONSIDERATION THAT THE UPPER
LEVEL WAVE IS WELL NORTH OF THE CWA...AND CONVECTION/SHOWERS OVER
LAKE MICHIGAN ARE ASSOCIATED WITH AN AREA OF 850 HPA WARM AIR
ADVECTION. SCT CU IS BEGINNING TO DEVELOP ROUGHLY ALONG THE I-55
CORRIDOR.
SKIES CLEAR TONIGHT AND EXPECTING A COMFORTABLE NIGHT DESPITE LOW
90S BEING REPORTED ACROSS THE CWA THIS AFTERNOON. OVERNIGHT LOWS
WILL BE IN THE MID 60S...EXCEPT FOR LOW 70S DOWNTOWN. SATURDAY WILL
BE MUCH LIKE TODAY...WITH A DRY AND HOT FORECAST. RAISED INHERITED
TEMPS SUCH THAT TOMORROWS HIGHS ARE A DEGREE OR TWO WARMER THAN
TODAY. COULD EVEN SEE AREAS IN THE SOUTHERN PORTIONS OF THE CWA
BEING A BIT WARMER THAN CURRENTLY FORECAST. MODEL SOUNDINGS
INDICATES THERE WILL BE PLENTY OF MIXING TOMORROW...THEREFORE WENT
WITH DEW POINTS SLIGHTLY LOWER THAN PREVIOUSLY FORECAST. MIN RH
VALUES WILL BE IN THE MID TO UPPER 20 PERCENT RANGE...BUT WITH LIGHT
WINDS FORECAST NOT ANTICIPATING ANY FIRE WEATHER HEADLINES. THAT
BEING SAID A FEW LOCATIONS MAY REACH RED FLAG CRITERIA...AS RFD DID
TODAY. KEPT PREVIOUS MIN TEMPS FOR SATURDAY NIGHT WITH MID TO UPPER
60S IN THE OUTLYING AREAS...AND IN THE LOW 70S DOWNTOWN.
SUNDAY THROUGH MONDAY NIGHT...
LOW PRESSURE CURRENTLY OVER SOUTHERN SASKATCHEWAN AND THE NORTHERN
GREAT PLAINS WILL MOVE EASTWARD ACROSS SOUTHERN CANADA THROUGH THE
WEEKEND. THE LOWS COLD FRONT PASSES THROUGH THE CWA LATE SUNDAY
NIGHT INTO MONDAY MORNING. PRECIP AHEAD OF THE COLD FRONT WAS THE
MAIN FORECAST CHALLENGE TODAY. THE NAM AND GFS LOOKED A BIT FAST
WHILE THE ECMWF HAS BEEN SLOWING THE PROGRESSION OF THE SHOWERS
AND THUNDERSTORMS THE PAST FEW RUNS. WENT WITH A NAM/ECMWF MIX
THAT WAS VERY SIMILAR TO THE PREVIOUS FORECASTS TIMING...WITH
PRECIP REACHING THE WESTERN EDGE OF THE CWA LATE SATURDAY NIGHT.
THAT BEING SAID...THE MODELS ARE INDICATING THE INITIAL UPPER
LEVEL VORTICITY STREAMER ASSOCIATED WITH FIRST WAVE OF PRECIP WILL
BE STRETCHED NORTH TO SOUTH AND FRACTURE SOMEWHERE OVER WISCONSIN.
THE SOUTHERN PART OF THE VORT STREAMER WILL THEN PROGRESS EASTWARD
BRINGING MUCH NEEDED RAIN TO NORTHERN ILLINOIS. CONFIDENCE IS
MEDIUM WITH THE TIMING AND PROGRESSION OF THE PRECIP...BUT HIGH
REGARDING THE POSSIBILITY OF IT BEING A SIGNIFICANT RAINFALL.
PW VALUES WILL BE AROUND TO SLIGHTLY ABOVE 2 INCHES AHEAD OF THE
FRONT...WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
AUGUST. THEREFORE SUBSTANTIAL RAINFALL IS POSSIBLE AND AS MENTIONED
IN THE PREVIOUS DISCUSSION...TRAINING CELLS COULD CAUSE ISOLATED
WATER PROBLEMS.
TEMPS ON SUNDAY WILL BE MUCH COOLER WITH AREAS WEST OF I-55 IN THE
UPPER 70S...AND LOW TO MID 80S EXPECTED EAST OF I-55. TEMPS REBOUND
SLIGHTLY ON MONDAY WITH HIGHS IN THE LOW TO MID 80S.
EXTENDED...TUESDAY THROUGH FRIDAY...
HIGH PRESSURE MOVES IN BEHIND THE COLD FRONT LEADING TO ANOTHER
EXTENDED PERIOD OF DRY WEATHER. TEMPS INCREASE THROUGHOUT THE
EXTENDED...AND COULD BE EVEN WARMER THAN FORECAST. EXPECTING UPPER
80S TO QUITE POSSIBLY 90S BY LATE NEXT WEEK.
JEE
&&
.FIRE WEATHER...
428 PM CDT
RH VALUES DROPPED INTO THE 20 PERCENT RANGE ACROSS PARTS OF THE
AREA TODAY...AND SIMILAR CONDITIONS ARE EXPECTED TOMORROW.
TEMPERATURES TOMORROW WILL ONCE AGAIN BE IN THE LOW TO MID
90S...WITH LOWER DEW POINTS THAN TODAY. AMPLE MIXING WILL LIKELY
LEAD TO DEW POINTS DROPPING INTO THE LOW 50S SATURDAY AFTERNOON.
MIN RH VALUES WILL BE IN THE LOW TO MID 20 PERCENT RANGE...HOWEVER
WIND SPEEDS WILL BE AROUND 10 MPH. WIND GUSTS WILL DEVELOP IN THE
AFTERNOON WITH GUSTS UP TO 20 MPH EXPECTED WEST OF I-39...AND
GUSTS AROUND 15 MPH EXPECTED EAST OF I-39. FUEL MOISTURE LEVELS
ARE ABOVE 10 PERCENT FOR MUCH OF NORTHERN ILLINOIS...WHILE AREAS
EAST OF I-55 HAVE 10-HOUR FUELS LESS THAN 10 PERCENT. THEREFORE
TWO OF THE THREE RED FLAG CONDITIONS MAY BE MET IN ISOLATED
LOCATIONS...SIMILAR TO TODAY...BUT NOT EXPECTING ALL THREE RED
FLAG CONDITIONS TO BE MET. THEREFORE NO FIRE WEATHER HEADLINES ARE
ANTICIPATED.
A COLD FRONT MOVES THROUGH THE REGION LATE SATURDAY NIGHT INTO
SUNDAY BRINGING A WIDESPREAD SOAKING RAIN AND COOLER TEMPERATURES
WITH IT.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SS-SSE WINDS AROUND 10 KT OCCASIONALLY GUSTING TO AROUND 15 KT
THROUGH DUSK.
* SLIGHT POTENTIAL LAKE BREEZE REACHING MDW AND/OR ORD BEFORE
SUNDOWN.
* VERY LOW PROB ISOLATED SHRA/TSRA OVER NE IL AND EXTREME SE WI
INTO THIS EVENING.
TRS
//DISCUSSION...UPDATED 22Z...
LAKE BREEZE ONLY MAKING VERY SLOW PROGRESS INLAND. 09-14 KT
SE-ESE WINDS RIGHT ALONG THE SHORE BUT FURTHER INLAND BEHIND
THE BOUNDARY THERE ARE SSE-SE 05-07KT. EXTRAPOLATION USING
RECENT MOVEMENT HAS ARRIVAL AT ORD NOT TIL 02Z. WINDS LATE
AFTERNOON INTO TONIGHT EXPECTED TO REMAIN OUT OF THE S-SSE.
FAIRLY WEAK CONVERGENCE ALONG LAKE BREEZE AND OTHER BOUNDARIES
BUT HAS BEEN ENOUGH TO GENERATE ISOLATED SHRA WITH ADDITIONAL
LIFT PROVIDED BY THE SHORT WAVE TROUGH CURRENTLY MOVING E ALONG
THE WESTERN IL-WI BORDER. EXPECT A FEW MORE ISOLATED SHOWERS
INTO EARLY EVENING THEN DISSIPATION OF THE HIGH BASED CU WITH
LOSS OF SURFACE HEATING WITH SUNSET.
TRS
PREVIOUS DISCUSSION...UPDATED 18Z...
SOUTH-SOUTHWEST WINDS ARE IN PLACE ACROSS THE TERMINALS TODAY...
THANKS TO BROAD SURFACE LOW PRESSURE TROUGH EXTENDING FROM CENTRAL
CANADA TO THE HIGH PLAINS. WHILE GUIDANCE INDICATES SFC WIND
DIRECTION MORE IN THE 170-190 DEG RANGE...OBSERVATIONS HAVE
VARIED MORE IN THE 180-240 DEG RANGE. AMDAR AIRCRAFT SOUNDINGS...
88D VAD WIND PROFILE AND THE WOLCOTT INDIANA WIND PROFILER DEPICT
SWLY WINDS ABOVE THE SURFACE WHICH WOULD SUGGEST MORE OF A SW OR
SSW DIRECTION WILL BE MAINTAINED WITH DEEP MIXING THIS AFTERNOON.
SPEEDS GENERALLY 15 KTS OR LESS THROUGH THE MIXED LAYER...SO
SPEEDS NOT THAT IMPRESSIVE AND GENERALLY AROUND 10 KTS WITH ANY
GUSTS EXPECTED TO BE 15 KTS OR LESS. WEAK LAKE BREEZE NOTED ALONG
THE IL LAKE MICHIGAN SHORE IS NOT ANTICIPATED TO PUSH INLAND
THROUGH ORD/MDW THIS AFTERNOON...THOUGH RECENT RAP/HRRR RUNS DO
INDICATE THIS. OVERALL WEAK LAKE BREEZE PUSH EXPECTED AND SOUTH-
SOUTHWEST GRADIENT DOES NOT INDICATE A STRONG THREAT FOR MAKING IT
INTO THE TERMINALS.
ONLY REAL MINOR CONCERN IS WITH THE OUTSIDE LOW PROBABILITY CHANCE
OF ISOLATED SHRA/TSRA DEVELOPMENT OVER SOUTHEAST WI/NORTHERN IL
THIS AFTERNOON. MID-LEVEL DISTURBANCE IS NOTED IN SATELLITE VAPOR
IMAGERY MOVING EAST ACROSS THE REGION...WITH RELATIVELY STEEP MID-
LEVEL LAPSE RATES DEPICTED IN REGIONAL 12Z SOUNDINGS. ELEVATED
ALTO-CU OVER NORTHERN IL EARLIER TODAY HAS DISSIPATED...THOUGH
MODEL FORECAST SOUNDINGS DEEPEN SURFACE BASED MIXED LAYER TO
AROUND 700 MB THIS AFTERNOON WHICH DOES RESULT IN SOME SHALLOW
MID-LEVEL INSTABILITY. HIGH-RES CONVECTION ALLOWING MODEL RUNS
INCLUDING THE HRRR/RAP AND LOCALLY RUN WRF DO INDICATE SOME
SPOTTY/ISOLATED SHRA/TSRA DEVELOPMENT OVER THE AREA DURING THE
MID/LATE AFTERNOON HOURS. SHALLOW NATURE OF MID-LEVEL INSTABILITY
AND RELATIVELY DRY LOW LEVEL AIR RESULTING IN HIGH LCL/LFC HEIGHTS
IN THE 9-10 KFT RANGE ARGUE AGAINST SIGNIFICANT PROBABILITY OR
COVERAGE HOWEVER...WITH ANY MEAGER POTENTIAL FOR CONVECTION MUCH
TOO LOW TO INCLUDE IN TAF.
SOUTH-SOUTHWEST WINDS BECOMING A LITTLE GUSTIER ARE EXPECTED
SATURDAY WITH A CONTINUATION OF VFR CONDITIONS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE ALL ELEMENTS...INCLUDING NO MORE THAN ISOLATED
SHRA WITH NEAR ZERO CHANCE OF OCCURRENCE AT OR IN IMMEDIATE
VICINITY OF TERMINALS.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR.
SUNDAY...TSRA LIKELY IN THE AFTERNOON AND EVE. DEVELOPING MVFR
LIKELY. IFR POSSIBLE BY NIGHT.
MONDAY...SLIGHT CHANCE OF MORNING TSRA.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
219 PM CDT
PATTERN REMAINS LARGELY UNCHANGED TODAY AND WILL CONTINUE TO PERSIST
THROUGH MUCH OF THE WEEKEND AS HIGH PRESSURE REMAINS ANCHORED OVER
THE EASTERN STATES AND LOW PRESSURE PERSISTS OVER THE CANADIAN
PRAIRIES. SOUTHERLY FLOW WILL CONTINUE ACROSS LAKE MICHIGAN UNTIL
LATE SUNDAY. THROUGH SUNDAY NIGHT...THE LOW PRESSURE IS FORECAST TO
DEEPEN AS IT LIFTS NORTHEAST TOWARDS HUDSON BAY...AND A TRAILING
COLD FRONT IS EXPECTED TO MOVE ACROSS LAKE MICHIGAN LATE SUNDAY
NIGHT INTO MONDAY TURNING WINDS TO THE WEST OR NORTHWEST. HIGH
PRESSURE WILL THEN BUILD ACROSS THE PLAINS STATES AND MOVE
EAST...BECOMING CENTERED JUST SOUTH OF THE GREAT LAKES REGION. THE
WINDS WILL BE LIGHT OVER THE SOUTHERN HALF OF THE LAKE CLOSE TO THE
HIGH CENTER...BUT THE NORTH HALF OF THE LAKE WILL SEE SLIGHTLY
WINDIER CONDITIONS AS ANOTHER AREA OF LOW PRESSURE DEVELOPS ACROSS
THE CANADIAN PRAIRIES AND A MODEST PRESSURE GRADIENT DEVELOPS OVER
NORTHERN LAKE MICHIGAN. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
444 PM CDT FRI AUG 24 2012
.DISCUSSION...
324 PM CDT
TODAY THROUGH SATURDAY NIGHT...
AN UPPER LEVEL DISTURBANCE IS SLOWLY PASSING THROUGH NORTHERN
WISCONSIN AND WILL CONTINUE EASTWARD THROUGH THE NORTHERN GREAT
LAKES THIS EVENING. SOME OF THE SHORT TERM MODELS INDICATE
SCATTERED SHOWERS WILL DEVELOP ACROSS NORTHERN ILLINOIS...BUT WILL
CONTINUE WITH A DRY FORECAST THIS AFTERNOON. LATEST RAP ANALYSIS
INDICATES AMPLE CAPE AND LOW LEVEL LAPSE RATES NEAR DRY
ADIABATIC...HOWEVER SUSPECTING THE RAP ANALYSIS MAY BE OVER
ESTIMATING CAPE VALUES. ALSO TOOK INTO CONSIDERATION THAT THE UPPER
LEVEL WAVE IS WELL NORTH OF THE CWA...AND CONVECTION/SHOWERS OVER
LAKE MICHIGAN ARE ASSOCIATED WITH AN AREA OF 850 HPA WARM AIR
ADVECTION. SCT CU IS BEGINNING TO DEVELOP ROUGHLY ALONG THE I-55
CORRIDOR.
SKIES CLEAR TONIGHT AND EXPECTING A COMFORTABLE NIGHT DESPITE LOW
90S BEING REPORTED ACROSS THE CWA THIS AFTERNOON. OVERNIGHT LOWS
WILL BE IN THE MID 60S...EXCEPT FOR LOW 70S DOWNTOWN. SATURDAY WILL
BE MUCH LIKE TODAY...WITH A DRY AND HOT FORECAST. RAISED INHERITED
TEMPS SUCH THAT TOMORROWS HIGHS ARE A DEGREE OR TWO WARMER THAN
TODAY. COULD EVEN SEE AREAS IN THE SOUTHERN PORTIONS OF THE CWA
BEING A BIT WARMER THAN CURRENTLY FORECAST. MODEL SOUNDINGS
INDICATES THERE WILL BE PLENTY OF MIXING TOMORROW...THEREFORE WENT
WITH DEWPOINTS SLIGHTLY LOWER THAN PREVIOUSLY FORECAST. MIN RH
VALUES WILL BE IN THE MID TO UPPER 20 PERCENT RANGE...BUT WITH LIGHT
WINDS FORECAST NOT ANTICIPATING ANY FIRE WEATHER HEADLINES. THAT
BEING SAID A FEW LOCATIONS MAY REACH RED FLAG CRITERIA...AS RFD DID
TODAY. KEPT PREVIOUS MIN TEMPS FOR SATURDAY NIGHT WITH MID TO UPPER
60S IN THE OUTLYING AREAS...AND IN THE LOW 70S DOWNTOWN.
SUNDAY THROUGH MONDAY NIGHT...
LOW PRESSURE CURRENTLY OVER SOUTHERN SASKATCHEWAN AND THE NORTHERN
GREAT PLAINS WILL MOVE EASTWARD ACROSS SOUTHERN CANADA THROUGH THE
WEEKEND. THE LOWS COLD FRONT PASSES THROUGH THE CWA LATE SUNDAY
NIGHT INTO MONDAY MORNING. PRECIP AHEAD OF THE COLD FRONT WAS THE
MAIN FORECAST CHALLENGE TODAY. THE NAM AND GFS LOOKED A BIT FAST
WHILE THE ECMWF HAS BEEN SLOWING THE PROGRESSION OF THE SHOWERS
AND THUNDERSTORMS THE PAST FEW RUNS. WENT WITH A NAM/ECMWF MIX
THAT WAS VERY SIMILAR TO THE PREVIOUS FORECASTS TIMING...WITH
PRECIP REACHING THE WESTERN EDGE OF THE CWA LATE SATURDAY NIGHT.
THAT BEING SAID...THE MODELS ARE INDICATING THE INITIAL UPPER
LEVEL VORTICITY STREAMER ASSOCIATED WITH FIRST WAVE OF PRECIP WILL
BE STRETCHED NORTH TO SOUTH AND FRACTURE SOMEWHERE OVER WISCONSIN.
THE SOUTHERN PART OF THE VORT STREAMER WILL THEN PROGRESS EASTWARD
BRINGING MUCH NEEDED RAIN TO NORTHERN ILLINOIS. CONFIDENCE IS
MEDIUM WITH THE TIMING AND PROGRESSION OF THE PRECIP...BUT HIGH
REGARDING THE POSSIBILITY OF IT BEING A SIGNIFICANT RAINFALL.
PW VALUES WILL BE AROUND TO SLIGHTLY ABOVE 2 INCHES AHEAD OF THE
FRONT...WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
AUGUST. THEREFORE SUBSTANTIAL RAINFALL IS POSSIBLE AND AS MENTIONED
IN THE PREVIOUS DISCUSSION...TRAINING CELLS COULD CAUSE ISOLATED
WATER PROBLEMS.
TEMPS ON SUNDAY WILL BE MUCH COOLER WITH AREAS WEST OF I-55 IN THE
UPPER 70S...AND LOW TO MID 80S EXPECTED EAST OF I-55. TEMPS REBOUND
SLIGHTLY ON MONDAY WITH HIGHS IN THE LOW TO MID 80S.
EXTENDED...TUESDAY THROUGH FRIDAY...
HIGH PRESSURE MOVES IN BEHIND THE COLD FRONT LEADING TO ANOTHER
EXTENDED PERIOD OF DRY WEATHER. TEMPS INCREASE THROUGHOUT THE
EXTENDED...AND COULD BE EVEN WARMER THAN FORECAST. EXPECTING UPPER
80S TO QUITE POSSIBLY 90S BY LATE NEXT WEEK.
JEE
&&
.FIRE WEATHER...
428 PM CDT
RH VALUES DROPPED INTO THE 20 PERCENT RANGE ACROSS PARTS OF THE
AREA TODAY...AND SIMILAR CONDITIONS ARE EXPECTED TOMORROW.
TEMPERATURES TOMORROW WILL ONCE AGAIN BE IN THE LOW TO MID
90S...WITH LOWER DEWPOINTS THAN TODAY. AMPLE MIXING WILL LIKELY
LEAD TO DEWPOINTS DROPPING INTO THE LOW 50S SATURDAY AFTERNOON.
MIN RH VALUES WILL BE IN THE LOW TO MID 20 PERCENT RANGE...HOWEVER
WIND SPEEDS WILL BE AROUND 10 MPH. WIND GUSTS WILL DEVELOP IN THE
AFTERNOON WITH GUSTS UP TO 20 MPH EXPECTED WEST OF I-39...AND
GUSTS AROUND 15 MPH EXPECTED EAST OF I-39. FUEL MOISTURE LEVELS
ARE ABOVE 10 PERCENT FOR MUCH OF NORTHERN ILLINOIS...WHILE AREAS
EAST OF I-55 HAVE 10-HOUR FUELS LESS THAN 10 PERCENT. THEREFORE
TWO OF THE THREE RED FLAG CONDITIONS MAY BE MET IN ISOLATED
LOCATIONS...SIMILAR TO TODAY...BUT NOT EXPECTING ALL THREE RED
FLAG CONDITIONS TO BE MET. THEREFORE NO FIRE WEATHER HEADLINES ARE
ANTICIPATED.
A COLD FRONT MOVES THROUGH THE REGION LATE SATURDAY NIGHT INTO
SUNDAY BRINGING A WIDESPREAD SOAKING RAIN AND COOLER TEMPERATURES
WITH IT.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH-SOUTHWEST WINDS 10-15 KTS THIS AFTERNOON BECOMING LIGHT
SOUTH THIS EVENING.
* LAKE BREEZE EXPECTED TO REMAIN EAST OF ORD/MDW.
* VERY LOW PROBABILITY OF ISOLATED SHRA/TSRA DEVELOPMENT OVER
NORTHEAST IL THIS AFTERNOON.
RATZER
//DISCUSSION...UPDATED 18Z...
SOUTH-SOUTHWEST WINDS ARE IN PLACE ACROSS THE TERMINALS TODAY...
THANKS TO BROAD SURFACE LOW PRESSURE TROUGH EXTENDING FROM CENTRAL
CANADA TO THE HIGH PLAINS. WHILE GUIDANCE INDICATES SFC WIND
DIRECTION MORE IN THE 170-190 DEG RANGE...OBSERVATIONS HAVE
VARIED MORE IN THE 180-240 DEG RANGE. AMDAR AIRCRAFT SOUNDINGS...
88D VAD WIND PROFILE AND THE WOLCOTT INDIANA WIND PROFILER DEPICT
SWLY WINDS ABOVE THE SURFACE WHICH WOULD SUGGEST MORE OF A SW OR
SSW DIRECTION WILL BE MAINTAINED WITH DEEP MIXING THIS AFTERNOON.
SPEEDS GENERALLY 15 KTS OR LESS THROUGH THE MIXED LAYER...SO
SPEEDS NOT THAT IMPRESSIVE AND GENERALLY AROUND 10 KTS WITH ANY
GUSTS EXPECTED TO BE 15 KTS OR LESS. WEAK LAKE BREEZE NOTED ALONG
THE IL LAKE MICHIGAN SHORE IS NOT ANTICIPATED TO PUSH INLAND
THROUGH ORD/MDW THIS AFTERNOON...THOUGH RECENT RAP/HRRR RUNS DO
INDICATE THIS. OVERALL WEAK LAKE BREEZE PUSH EXPECTED AND SOUTH-
SOUTHWEST GRADIENT DOES NOT INDICATE A STRONG THREAT FOR MAKING IT
INTO THE TERMINALS.
ONLY REAL MINOR CONCERN IS WITH THE OUTSIDE LOW PROBABILITY CHANCE
OF ISOLATED SHRA/TSRA DEVELOPMENT OVER SOUTHEAST WI/NORTHERN IL
THIS AFTERNOON. MID-LEVEL DISTURBANCE IS NOTED IN SATELLITE VAPOR
IMAGERY MOVING EAST ACROSS THE REGION...WITH RELATIVELY STEEP MID-
LEVEL LAPSE RATES DEPICTED IN REGIONAL 12Z SOUNDINGS. ELEVATED
ALTO-CU OVER NORTHERN IL EARLIER TODAY HAS DISSIPATED...THOUGH
MODEL FORECAST SOUNDINGS DEEPEN SURFACE BASED MIXED LAYER TO
AROUND 700 MB THIS AFTERNOON WHICH DOES RESULT IN SOME SHALLOW
MID-LEVEL INSTABILITY. HIGH-RES CONVECTION ALLOWING MODEL RUNS
INCLUDING THE HRRR/RAP AND LOCALLY RUN WRF DO INDICATE SOME
SPOTTY/ISOLATED SHRA/TSRA DEVELOPMENT OVER THE AREA DURING THE
MID/LATE AFTERNOON HOURS. SHALLOW NATURE OF MID-LEVEL INSTABILITY
AND RELATIVELY DRY LOW LEVEL AIR RESULTING IN HIGH LCL/LFC HEIGHTS
IN THE 9-10 KFT RANGE ARGUE AGAINST SIGNIFICANT PROBABILITY OR
COVERAGE HOWEVER...WITH ANY MEAGER POTENTIAL FOR CONVECTION MUCH
TOO LOW TO INCLUDE IN TAF.
SOUTH-SOUTHWEST WINDS BECOMING A LITTLE GUSTIER ARE EXPECTED
SATURDAY WITH A CONTINUATION OF VFR CONDITIONS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ALL ELEMENTS.
* HIGH CONFIDENCE IN ANY SHRA/TSRA BEING LOW COVERAGE IF THEY WERE
TO DEVELOP.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR.
SUNDAY...TSRA LIKELY IN THE AFTERNOON AND EVE. DEVELOPING MVFR
LIKELY. IFR POSSIBLE BY NIGHT.
MONDAY...SLIGHT CHANCE OF MORNING TSRA.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
219 PM CDT
PATTERN REMAINS LARGELY UNCHANGED TODAY AND WILL CONTINUE TO PERSIST
THROUGH MUCH OF THE WEEKEND AS HIGH PRESSURE REMAINS ANCHORED OVER
THE EASTERN STATES AND LOW PRESSURE PERSISTS OVER THE CANADIAN
PRAIRIES. SOUTHERLY FLOW WILL CONTINUE ACROSS LAKE MICHIGAN UNTIL
LATE SUNDAY. THROUGH SUNDAY NIGHT...THE LOW PRESSURE IS FORECAST TO
DEEPEN AS IT LIFTS NORTHEAST TOWARDS HUDSON BAY...AND A TRAILING
COLD FRONT IS EXPECTED TO MOVE ACROSS LAKE MICHIGAN LATE SUNDAY
NIGHT INTO MONDAY TURNING WINDS TO THE WEST OR NORTHWEST. HIGH
PRESSURE WILL THEN BUILD ACROSS THE PLAINS STATES AND MOVE
EAST...BECOMING CENTERED JUST SOUTH OF THE GREAT LAKES REGION. THE
WINDS WILL BE LIGHT OVER THE SOUTHERN HALF OF THE LAKE CLOSE TO THE
HIGH CENTER...BUT THE NORTH HALF OF THE LAKE WILL SEE SLIGHTLY
WINDIER CONDITIONS AS ANOTHER AREA OF LOW PRESSURE DEVELOPS ACROSS
THE CANADIAN PRAIRIES AND A MODEST PRESSURE GRADIENT DEVELOPS OVER
NORTHERN LAKE MICHIGAN. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
327 PM CDT FRI AUG 24 2012
.DISCUSSION...
324 PM CDT
TODAY THROUGH SATURDAY NIGHT...
AN UPPER LEVEL DISTURBANCE IS SLOWLY PASSING THROUGH NORTHERN
WISCONSIN AND WILL CONTINUE EASTWARD THROUGH THE NORTHERN GREAT
LAKES THIS EVENING. SOME OF THE SHORT TERM MODELS INDICATE
SCATTERED SHOWERS WILL DEVELOP ACROSS NORTHERN ILLINOIS...BUT WILL
CONTINUE WITH A DRY FORECAST THIS AFTERNOON. LATEST RAP ANALYSIS
INDICATES AMPLE CAPE AND LOW LEVEL LAPSE RATES NEAR DRY
ADIABATIC...HOWEVER SUSPECTING THE RAP ANALYSIS MAY BE OVER
ESTIMATING CAPE VALUES. ALSO TOOK INTO CONSIDERATION THAT THE UPPER
LEVEL WAVE IS WELL NORTH OF THE CWA...AND CONVECTION/SHOWERS OVER
LAKE MICHIGAN ARE ASSOCIATED WITH AN AREA OF 850 HPA WARM AIR
ADVECTION. SCT CU IS BEGINNING TO DEVELOP ROUGHLY ALONG THE I-55
CORRIDOR.
SKIES CLEAR TONIGHT AND EXPECTING A COMFORTABLE NIGHT DESPITE LOW
90S BEING REPORTED ACROSS THE CWA THIS AFTERNOON. OVERNIGHT LOWS
WILL BE IN THE MID 60S...EXCEPT FOR LOW 70S DOWNTOWN. SATURDAY WILL
BE MUCH LIKE TODAY...WITH A DRY AND HOT FORECAST. RAISED INHERITED
TEMPS SUCH THAT TOMORROWS HIGHS ARE A DEGREE OR TWO WARMER THAN
TODAY. COULD EVEN SEE AREAS IN THE SOUTHERN PORTIONS OF THE CWA
BEING A BIT WARMER THAN CURRENTLY FORECAST. MODEL SOUNDINGS
INDICATES THERE WILL BE PLENTY OF MIXING TOMORROW...THEREFORE WENT
WITH DEWPOINTS SLIGHTLY LOWER THAN PREVIOUSLY FORECAST. MIN RH
VALUES WILL BE IN THE MID TO UPPER 20 PERCENT RANGE...BUT WITH LIGHT
WINDS FORECAST NOT ANTICIPATING ANY FIRE WEATHER HEADLINES. THAT
BEING SAID A FEW LOCATIONS MAY REACH RED FLAG CRITERIA...AS RFD DID
TODAY. KEPT PREVIOUS MIN TEMPS FOR SATURDAY NIGHT WITH MID TO UPPER
60S IN THE OUTLYING AREAS...AND IN THE LOW 70S DOWNTOWN.
SUNDAY THROUGH MONDAY NIGHT...
LOW PRESSURE CURRENTLY OVER SOUTHERN SASKATCHEWAN AND THE NORTHERN
GREAT PLAINS WILL MOVE EASTWARD ACROSS SOUTHERN CANADA THROUGH THE
WEEKEND. THE LOWS COLD FRONT PASSES THROUGH THE CWA LATE SUNDAY
NIGHT INTO MONDAY MORNING. PRECIP AHEAD OF THE COLD FRONT WAS THE
MAIN FORECAST CHALLENGE TODAY. THE NAM AND GFS LOOKED A BIT FAST
WHILE THE ECMWF HAS BEEN SLOWING THE PROGRESSION OF THE SHOWERS
AND THUNDERSTORMS THE PAST FEW RUNS. WENT WITH A NAM/ECMWF MIX
THAT WAS VERY SIMILAR TO THE PREVIOUS FORECASTS TIMING...WITH
PRECIP REACHING THE WESTERN EDGE OF THE CWA LATE SATURDAY NIGHT.
THAT BEING SAID...THE MODELS ARE INDICATING THE INITIAL UPPER
LEVEL VORTICITY STREAMER ASSOCIATED WITH FIRST WAVE OF PRECIP WILL
BE STRETCHED NORTH TO SOUTH AND FRACTURE SOMEWHERE OVER WISCONSIN.
THE SOUTHERN PART OF THE VORT STREAMER WILL THEN PROGRESS EASTWARD
BRINGING MUCH NEEDED RAIN TO NORTHERN ILLINOIS. CONFIDENCE IS
MEDIUM WITH THE TIMING AND PROGRESSION OF THE PRECIP...BUT HIGH
REGARDING THE POSSIBILITY OF IT BEING A SIGNIFICANT RAINFALL.
PW VALUES WILL BE AROUND TO SLIGHTLY ABOVE 2 INCHES AHEAD OF THE
FRONT...WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
AUGUST. THEREFORE SUBSTANTIAL RAINFALL IS POSSIBLE AND AS MENTIONED
IN THE PREVIOUS DISCUSSION...TRAINING CELLS COULD CAUSE ISOLATED
WATER PROBLEMS.
TEMPS ON SUNDAY WILL BE MUCH COOLER WITH AREAS WEST OF I-55 IN THE
UPPER 70S...AND LOW TO MID 80S EXPECTED EAST OF I-55. TEMPS REBOUND
SLIGHTLY ON MONDAY WITH HIGHS IN THE LOW TO MID 80S.
EXTENDED...TUESDAY THROUGH FRIDAY...
HIGH PRESSURE MOVES IN BEHIND THE COLD FRONT LEADING TO ANOTHER
EXTENDED PERIOD OF DRY WEATHER. TEMPS INCREASE THROUGHOUT THE
EXTENDED...AND COULD BE EVEN WARMER THAN FORECAST. EXPECTING UPPER
80S TO QUITE POSSIBLY 90S BY LATE NEXT WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH-SOUTHWEST WINDS 10-15 KTS THIS AFTERNOON BECOMING LIGHT
SOUTH THIS EVENING.
* LAKE BREEZE EXPECTED TO REMAIN EAST OF ORD/MDW.
* VERY LOW PROBABILITY OF ISOLATED SHRA/TSRA DEVELOPMENT OVER
NORTHEAST IL THIS AFTERNOON.
RATZER
//DISCUSSION...UPDATED 18Z...
SOUTH-SOUTHWEST WINDS ARE IN PLACE ACROSS THE TERMINALS TODAY...
THANKS TO BROAD SURFACE LOW PRESSURE TROUGH EXTENDING FROM CENTRAL
CANADA TO THE HIGH PLAINS. WHILE GUIDANCE INDICATES SFC WIND
DIRECTION MORE IN THE 170-190 DEG RANGE...OBSERVATIONS HAVE
VARIED MORE IN THE 180-240 DEG RANGE. AMDAR AIRCRAFT SOUNDINGS...
88D VAD WIND PROFILE AND THE WOLCOTT INDIANA WIND PROFILER DEPICT
SWLY WINDS ABOVE THE SURFACE WHICH WOULD SUGGEST MORE OF A SW OR
SSW DIRECTION WILL BE MAINTAINED WITH DEEP MIXING THIS AFTERNOON.
SPEEDS GENERALLY 15 KTS OR LESS THROUGH THE MIXED LAYER...SO
SPEEDS NOT THAT IMPRESSIVE AND GENERALLY AROUND 10 KTS WITH ANY
GUSTS EXPECTED TO BE 15 KTS OR LESS. WEAK LAKE BREEZE NOTED ALONG
THE IL LAKE MICHIGAN SHORE IS NOT ANTICIPATED TO PUSH INLAND
THROUGH ORD/MDW THIS AFTERNOON...THOUGH RECENT RAP/HRRR RUNS DO
INDICATE THIS. OVERALL WEAK LAKE BREEZE PUSH EXPECTED AND SOUTH-
SOUTHWEST GRADIENT DOES NOT INDICATE A STRONG THREAT FOR MAKING IT
INTO THE TERMINALS.
ONLY REAL MINOR CONCERN IS WITH THE OUTSIDE LOW PROBABILITY CHANCE
OF ISOLATED SHRA/TSRA DEVELOPMENT OVER SOUTHEAST WI/NORTHERN IL
THIS AFTERNOON. MID-LEVEL DISTURBANCE IS NOTED IN SATELLITE VAPOR
IMAGERY MOVING EAST ACROSS THE REGION...WITH RELATIVELY STEEP MID-
LEVEL LAPSE RATES DEPICTED IN REGIONAL 12Z SOUNDINGS. ELEVATED
ALTO-CU OVER NORTHERN IL EARLIER TODAY HAS DISSIPATED...THOUGH
MODEL FORECAST SOUNDINGS DEEPEN SURFACE BASED MIXED LAYER TO
AROUND 700 MB THIS AFTERNOON WHICH DOES RESULT IN SOME SHALLOW
MID-LEVEL INSTABILITY. HIGH-RES CONVECTION ALLOWING MODEL RUNS
INCLUDING THE HRRR/RAP AND LOCALLY RUN WRF DO INDICATE SOME
SPOTTY/ISOLATED SHRA/TSRA DEVELOPMENT OVER THE AREA DURING THE
MID/LATE AFTERNOON HOURS. SHALLOW NATURE OF MID-LEVEL INSTABILITY
AND RELATIVELY DRY LOW LEVEL AIR RESULTING IN HIGH LCL/LFC HEIGHTS
IN THE 9-10 KFT RANGE ARGUE AGAINST SIGNIFICANT PROBABILITY OR
COVERAGE HOWEVER...WITH ANY MEAGER POTENTIAL FOR CONVECTION MUCH
TOO LOW TO INCLUDE IN TAF.
SOUTH-SOUTHWEST WINDS BECOMING A LITTLE GUSTIER ARE EXPECTED
SATURDAY WITH A CONTINUATION OF VFR CONDITIONS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ALL ELEMENTS.
* HIGH CONFIDENCE IN ANY SHRA/TSRA BEING LOW COVERAGE IF THEY WERE
TO DEVELOP.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR.
SUNDAY...TSRA LIKELY IN THE AFTERNOON AND EVE. DEVELOPING MVFR
LIKELY. IFR POSSIBLE BY NIGHT.
MONDAY...SLIGHT CHANCE OF MORNING TSRA.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
219 PM CDT
PATTERN REMAINS LARGELY UNCHANGED TODAY AND WILL CONTINUE TO PERSIST
THROUGH MUCH OF THE WEEKEND AS HIGH PRESSURE REMAINS ANCHORED OVER
THE EASTERN STATES AND LOW PRESSURE PERSISTS OVER THE CANADIAN
PRAIRIES. SOUTHERLY FLOW WILL CONTINUE ACROSS LAKE MICHIGAN UNTIL
LATE SUNDAY. THROUGH SUNDAY NIGHT...THE LOW PRESSURE IS FORECAST TO
DEEPEN AS IT LIFTS NORTHEAST TOWARDS HUDSON BAY...AND A TRAILING
COLD FRONT IS EXPECTED TO MOVE ACROSS LAKE MICHIGAN LATE SUNDAY
NIGHT INTO MONDAY TURNING WINDS TO THE WEST OR NORTHWEST. HIGH
PRESSURE WILL THEN BUILD ACROSS THE PLAINS STATES AND MOVE
EAST...BECOMING CENTERED JUST SOUTH OF THE GREAT LAKES REGION. THE
WINDS WILL BE LIGHT OVER THE SOUTHERN HALF OF THE LAKE CLOSE TO THE
HIGH CENTER...BUT THE NORTH HALF OF THE LAKE WILL SEE SLIGHTLY
WINDIER CONDITIONS AS ANOTHER AREA OF LOW PRESSURE DEVELOPS ACROSS
THE CANADIAN PRAIRIES AND A MODEST PRESSURE GRADIENT DEVELOPS OVER
NORTHERN LAKE MICHIGAN. BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
353 PM EDT FRI AUG 24 2012
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 348 PM EDT FRI AUG 24 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A GENERAL ZONAL
FLOW OVER THE NRN TIER CONUS/SRN CANADA. A SHRTWV EMBEDDED IN THIS
FLOW IS PRESENT OVER WI/UPR MI EARLY THIS AFTN AND HAS BEEN
SUPPORTING SOME ISOLD -SHRA/A FEW TS OVER MAINLY THE E HALF OF THE
CWA DESPITE PRESENCE OF DRY LLVL AIR SHOWN ON THE 12Z GRB/APX RAOBS
THAT EXTENDS WELL TO THE S AS DEPICTED ON THE 12Z RAOB FM QUAD
CITIES IOWA. OVER THE W HALF...NVA IN THE WAKE OF THE SHRTWV AND
AGGRESSIVE DRYING FOCUSED AT H5-7 WITH ENEWD SPREAD OF AIRMASS SHOWN
ON THE 12Z MPX RAOB HAS SUPPRESSED SHRA AND RESULTED IN SOME CLRG IN
DESPITE PERSISTENCE OF AXIS OF HIER H85 DEWPTS/THETA-E IN THAT AREA
PER RUC ANALYSIS. SHRTWV RDG AXIS OVER MN IS BRINGING DRY WX THERE
ALONG WITH MOCLR SKIES...BUT MORE CLDS AND SOME SHRA/TS ARE OVER THE
NRN PLAINS IN ADVANCE OF POTENT SHRTWV MOVING EWD THRU SRN ALBERTA.
LATE THIS AFTN...DESPITE NVA/AGGRESSIVE UPR DRYING IN THE WAKE OF
SLOW MOVING SHRTWV...SUSPECT SOME SHRA/TS MAY DVLP ON THE LEADING
EDGE OF THE H5-7 DRYING WHERE MORE INSOLATION WL COINCIDE WITH AREA
OF HIER H85 DEWPTS. A NUMBER OF THE RECENT HIER RES MODELS SHOW AT
LEAST ISOLD-SCT SHRA/TS DVLPG OVER THE CENTRAL ZNS...SO PAINTED AN
AXIS OF SOMEWHAT HIER CHC POPS IN THIS AREA. THE FAR W SHOULD BE DRY
UNDER MUCH DRIER H7-5 AIR AND WITH SOME MODERATION NEAR LK SUP.
LINGERING LLVL DRY AIR OVER THE E SHOULD ALSO LIMIT POPS IN THAT
AREA DESPITE MORE MID LVL MSTR THAT MIGHT SUPPORT PERSISTENT -SHRA.
TNGT...AS DEEPER SHRTWV OVER SW CANADA THIS MRNG DRIFTS EWD AND
SHRTWV OVER THE AREA SHIFTS TO THE E...ARRIVAL OF SHRTWV RDG FM MN/
ASSOCIATED H5 RISES IN CONCERT WITH LOSS OF DAYTIME HEATING SHOULD
CAUSE ANY EVNG SHRA/TS OVER MAINLY THE E AND CENTRAL ZNS TO
DISSIPATE. PCPN CHCS WL LINGER LONGEST OVER THE E CLOSER TO
DEPARTING SHRTWV/WHERE MID LVL MSTR REMAINS MOST ABUNDANT LONGEST.
ALTHOUGH THERE WAS QUITE A BIT OF FOG LAST NGT OVER MN...THE 12Z
NAM/LOCAL WRF-ARW SHOW PERSISTENT SSW LLVL FLOW DRAWING DRIER AIR
SHOWN ON THE 12Z GRB/QUAD CITY RAOBS INTO THE FA. SO EXPECT NO FOG
TO IMPACT THE CWA. DESPITE THE DRYING COLUMN...STEADY S WIND SHOULD
LIMIT THE DIURNAL TEMP FALL AT MOST SPOTS...FURTHER LIMITING THE
POTENTIAL FOR FOG.
SAT...FOCUS TURNS TO HOW QUICKLY STRONG DISTURBANCE OVER SW CANADA
THIS MRNG MIGHT INFLUENCE THE WX ESPECIALLY OVER THE WRN CWA. THE
DAY SHOULD AT LEAST START MOSUNNY WITH SHRTWV RDG AXIS/DRY H85-5
AIRMASS OVHD. BY 00Z SUN...THE SHRTWV IS PROGGED TO DRIFT NEWD TO
NEAR LK WINNIPEG AND BECOME OCCLUDED WITH H5 CUTOFF NEARLY OVER
992MB SFC LO. SINCE LLVL SLY FLOW IS FCST TO ADVECT THE DRIER
SFC-H85 AIR NOTED TO THE S OVER THE CWA THRU THE DAY AND BULK OF
DEEP LYR QVECTOR CNVGC OVER WARM CONVEYOR BELT MSTR/ATTENDANT SFC
COLD FNT ARE PROGGED TO RACH ONLY THE FAR W BY 00Z SUN...OPTED TO
SLOW DOWN EWD PUSH OF ACCOMPANYING POPS. GIVEN THE STRENGTH OF THE
SHRTWV TO THE W...PREFER THE HIER H85 FCST TEMPS BY THE NAM...WHICH
SHOWS THIS TEMP REACHING 20C OVER THE CWA VERSUS ONLY 17C BY THE
GFS. DEEP MIXING ON THE NAM FCST SDNGS YIELDS HI TEMPS REACHING ARND
90. MAX TEMPS WL BE HIEST NEAR LK SUP WHERE SLY FLOW DOWNSLOPES AND
LIMITS AND MODERATION OFF LK SUP. IN FACT...SOME RECORD HI TEMPS MAY
FALL ON SAT. AREAS DOWNWIND OF LK MI WL BE COOLEST. WITH SFC DEWPTS
LIKELY TO MIX OUT TO ARND 50 AWAY FM LK MODERATION...MIN RH WL DIP
AS LO AS 25 PCT IN THE PRESENCE OF WIND GUSTS TO 20-25 MPH ENHANCED
BY THE MIXING. FORTUNATELY...RECENT RAINS HAVE MOISTENED THE GROUND
SUFFICIENTLY TO MINIMIZE ANY FIRE WX IMPACTS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 348 PM EDT FRI AUG 24 2012
AN UPPER-LEVEL TROUGH AND SLOW-MOVING COLD FRONT WILL CONTINUE TO
BRING RAIN AND THUNDERSTORM CHANCES TO UPPER MI THROUGH MONDAY
BEFORE DRY AND WARMER WEATHER RETURNS UNDER HIGH PRESSURE FOR THE
MIDDLE OF THE WEEK.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...A SHARP TROUGH CURRENTLY
MOVING THROUGH ALBERTA AND NORTHERN MT WILL SHIFT EAST THROUGH
SATURDAY AND INDUCE A STRONG SFC LOW OVER SOUTHERN SASKATCHEWAN. BY
SATURDAY NIGHT...THE TROUGH WILL BE LIFTING TO THE NORTHEAST THROUGH
MANITOBA WHILE BECOMING NEARLY STACKED WITH THE ASSOCIATED SFC LOW.
A COLD FRONT EXTENDING FROM A NEW OCCLUSION OVER WESTERN ONTARIO
WILL BE SURGING EASTWARD THROUGH MN SATURDAY AFTERNOON. THERE IS
VERY GOOD MODEL AGREEMENT THAT THIS COLD FRONT WILL REACH THE
WESTERN TIP OF THE CWA BY 06Z SUNDAY...THEN WASH OUT ACROSS THE
CENTRAL CWA BY SUNDAY AFTERNOON AS IT LOSES SUPPORT FROM THE
WEAKENING STACKED LOW. A SECONDARY SFC TROUGH WILL THEN CATCH UP TO
THE FRONT AND HELP KICK IT OUT OF THE CWA BY SUNDAY EVENING.
NOT TOO CONFIDENT ON WIDESPREAD PRECIP CHANCES ATTM FOR SEVERAL
REASONS. FIRST...BEST Q-VECTOR CONVERGENCE WILL EXIST NORTH CLOSER
TO THE MID-LEVEL LOW...AND SOUTH WHERE A SHORTWAVE TROUGH WILL BE
MOVING INTO THE MID-MS VALLEY FROM THE SOUTHERN PLAINS. NEXT...THE
SFC LOW FORMING IN RESPONSE TO THE SOUTHERN PLAINS TROUGH WILL
LIKELY CUTOFF A SIGNIFICANT PORTION OF THE MOISTURE SUPPLY AHEAD OF
THE FRONT. THUS...APPRECIABLE MOISTURE WILL BE CONFINED TO THE NEAR
SFC LAYER OVER UPPER MI. ANY PRECIP THAT FORMS WILL BE FORCED BY A
BAND OF H8-H7 FRONTOGENESIS ALONG THE FRONT...THOUGH MOISTURE WILL
BE LACKING IN THIS LAYER. CUT BACK POPS TO LOW CHANCE FOR MUCH OF
THE LAND...WITH HIGHER POPS OVER THE WESTERN LAKE AS IT WILL BE
CLOSER TO BETTER FORCING FROM THE LOW. SOME SFC HEATING WILL AID
DEVELOPMENT OF NEW SHOWERS AND THUNDERSTORMS IN THE AFTERNOON ACROSS
THE EAST HALF...BUT ONCE AGAIN...A LACK OF MOISTURE WILL STILL BE A
CONCERN.
INCREASED/DECREASED HIGHS IN THE WEST/EAST FOR SUNDAY TO ACCOUNT FOR
CLOUD AND PRECIP TRENDS. EXPECTATION IS THAT CLOUDS WILL QUICKLY
CLEAR WEST IN THE MORNING. H8 TEMPS WILL COOL TO AROUND 14C WITH
THIS CLEARING...BUT SHOULD STILL BE WARM ENOUGH TO PRODUCE LOW 80S
FOR HIGHS. PATCHY FOG COULD BE POSSIBLE FOR THE INTERIOR WEST SUNDAY
NIGHT...BUT DRY AIR ADVECTING INTO THE AREA SHOULD BE ENOUGH TO
SUBDUE THE THREAT.
MONDAY AND MONDAY NIGHT...AS THE MID-LEVEL LOW DRIFTS NORTHEASTWARD
TO HUDSON BAY SUNDAY NIGHT...IT WILL TAP INTO SOME ENERGY FROM THE
RAGGED POLAR VORTEX OVER NORTHERN NUNAVUT. THE REINFORCED TROUGH AND
WEAK SFC TROUGH ARE THEN PROGGED TO AFFECT THE AREA MONDAY NIGHT.
MODELS BEGIN TO DIVERGE SIGNIFICANTLY BY THIS POINT...BUT VERY
LITTLE MOISTURE ABOVE THE SFC MIXED LAYER WILL LIKELY PREVENT ANY
PRECIP. EVEN MORE...DO NOT EXPECT MUCH CLOUD COVER EXCEPT FOR
POSSIBLE AFTERNOON CUMULUS. HIGHS WILL BE IN THE 70S...WITH THE
COOLEST TEMPS NORTH CLOSER TO A H8 TEMP MIN IN NORTHERN ONTARIO.
TUESDAY THROUGH THURSDAY...A VERY IMPRESSIVE RIDGE WILL SLOWLY EDGE
INTO THE UPPER GREAT LAKES BEGINNING TUESDAY...WITH THE SFC HIGH
PRESSURE CENTERING ITSELF OVER WI/UPPER MI BY WEDNESDAY MORNING. THE
HIGH WILL CONTINUE TO GRADUALLY DRIFT SOUTHEASTWARD WEDNESDAY
THROUGH THURSDAY...WITH UPPER MI REMAINING UNDER ITS INFLUENCE.
INCREASED HIGHS THROUGH FRIDAY AS THERE WILL BE PLENTY OF SUN AND
WARM H8 TEMPS. ISENTROPIC LIFT ON THE 305-310 THEATA SFCS IN
ADDITION TO H8 MOISTURE TRANSPORT MAY RESULT IN A FEW SHOWERS AND
THUNDERSTORMS WEDNESDAY NIGHT...MAINLY NORTH.
FRIDAY...THERE IS MODEL AGREEMENT THAT THE RIDGE WILL BEGIN TO BREAK
DOWN BY EARLY FRIDAY. THE GFS IS ONCE AGAIN MORE AGGRESSIVE THAN THE
ECMWF WITH A TROUGH FROM BRITISH COLUMBIA MOVING INTO THE RIDGE. IT
IS DIFFICULT TO SAY WHICH MODEL WILL PAN OUT...IF EITHER...SO WILL
GO WITH A MODEL CONSENSUS FOR THE FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 125 PM EDT FRI AUG 24 2012
ALTHOUGH THERE COULD BE SOME -SHRA AND EVEN A TS AT SAW THIS AFTN...
EXPECT VFR CONDITIONS AT ALL 3 SITES THRU THIS FCST PERIOD WITH
RELATIVELY DRY LLVL AIR IN PLACE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 24 2012
EXCEPT FOR A STRONGER S WIND UP TO 25 KTS OVER THE E INTO THIS
EVENING AHEAD OF AN APPROACHING LO PRES TROF...WINDS THRU THE
FORECAST PERIOD WILL BE NO HIER THAN 20 KTS AS THE COMBINATION OF A
WEAK PRES GRADIENT AND HIER OVERWATER STABILITY LIMIT WIND SPEEDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TK
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 PM EDT FRI AUG 24 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 523 AM EDT FRI AUG 24 2012
00Z RAOBS AND RUC ANALYSIS INDICATES ZONAL FLOW ALOFT DOWNSTREAM OF
SHARP TROUGH OVER WESTERN CANADA AND ON PERIPHERY OF BROAD RIDGE
OVER CENTRAL CONUS. AT THE SFC...DISJOINTED COMPLEX OF TROUGHS ARE
PRESENT FROM SAKSATCHEWAN INTO NORTH DAKOTA.
HAVE A DOWNRIGHT MESS OF CONVECTION OVER UPR LAKES THIS MORNING
AHEAD OF PAIR OF STRONGER SHORTWAVE TROUGHS MOVING INTO NORTHWEST
ONTARIO AND INTO SOUTHWEST WISCONSIN. H85 WARM ADVECTION IS
SUPPORTING MORE WEST-TO-EAST ORIENTED SHRA/TSRA OVR LK SUPERIOR
WHILE HEIGHT FALLS AND H85-H7 MOISTURE ADVECTION ALONG 2-5KM MUCAPE
RIBBON AND ALONG WEST EDGE OF H85 JET IS SPURRING ON MULTIPLE
CLUSTERS OF MODERATE-HEAVY SHRA/TSRA FROM SOUTHWEST LK SUPERIOR INTO
NORTHWEST WI AND INTO SOUTHWEST WI. ACTIVITY OVR SOUTHWEST WI IS
MORE ORGANIZED WITH SHARPER HEIGHT FALLS OVR THAT AREA DUE TO
SHORTWAVE. ENTIRE AREA IS WITHIN INFLUENCE OF BROAD DIVERGENCE
ALOFT AS H3 JET STREAK SURGES IN FROM THE NORTHERN PLAINS.
CURRENT RADAR TRENDS AND EXPECTED POSITION OF LOW-LEVEL JET THROUGH
MID MORNING SUGGESTS THAT SHRA/TSRA OVER WESTERN LK SUPERIOR WILL
LIFT ACROSS KEWEENAW AND REST OF LK SUPERIOR THIS MORNING. IT APPEARS
THAT CONVECTION OVER SOUTHWEST WISCONSIN WILL NOT MAKE MUCH PUSH
INTO UPR MICHIGAN AS PRIMARY SHORTWAVE STAYS MAINLY OVR WISCONSIN.
LOOKS LIKE MAIN EFFECT OF BOTH AREAS OF CONVECTION WILL BE TO KEEP
SCT-BKN MID CLOUDS IN OVER MOST CWA THIS MORNING...BUT DO EXPECT
SOME HEATING. BETTER HEATING OCCURS EARLY TO MID AFTN AND COULD TIME
OUT WELL WITH ARRIVAL OF SURGE OF H85-H7 MOISTURE FROM THE SOUTHWEST.
THERE IS CURRENTLY A VERY SHARP EDGE TO THE H7 MOISTURE AS SEEN WITH
ABRUPT CLEARING SEEN OVER SOUTHERN MINNESOTA. SREF /WHICH HAS OKAY
HANDLE ON CURRENT CONVECTIVE TRENDS/ BLASTS THIS DRY MID-LEVEL AIR
INTO WEST THIRD BY EARLY AFTN WITH MOISTURE GRADIENT SETTING UP OVR
CENTRAL CWA. DEPENDING ON EXTENT OF HEATING...INSTABILITY COULD
INCREASE WITH ML BASED CAPES OVR 1000 J/KG IN THE CNTRL CWA 18Z-22Z.
TRIGGER WOULD BE SHORTWAVE TROUGH AND SFC-H85 THETA-E ADVECTION AND
MAYBE DEVELOPING LK BREEZES /THOUGH WITH FAIRLY STRONG 950MB INTO
AFTN NOT AS CONFIDENT IN THIS POSSIBLE TRIGGER/. DEEP LAYER SHEAR
ENDS UP AROUND 30 KTS DURING THE AFTN...SO AT LEAST BRIEF
ORGANIZATION/STRONG STORMS SEEMS POSSIBLE GIVEN THE INSTABILITY.
OVERALL...THINK SETUP CONTINUES TO JUSTIFY GOING FCST OF SCT POPS
MAINLY IN THE AFTN...HIGHEST OVER CENTRAL CWA. CONTINUED TO TRIM
POPS OVER WEST...JUST TOO MUCH DRYING TO TRIGGER ANY ADDITIONAL
CONVECTION THERE. BASED ON CURRENT RADAR/SATELLITE TRENDS...THINK
CLEARING IS LIKELY OVR MOST OF CWA THROUGH THE MORNING. SO...WARMER
TEMPS AS NAM INDICATES ARE PREFERRED. BASED ON MIXING TO H85 TEMPS
NEAR +19C...MAX TEMPS MAY TOP OUT WELL INTO THE UPPER 80S. WARM
START TO THE DAY WILL NOT HINDER THIS PROCESS EITHER.
SHORTWAVE TROUGH/MOISTURE ADVECTION CRUISES EAST EARLY THIS EVENING
AND OTHER THAN SOME SMALL CHANCES HAVE PRETTY MUCH ENDED POPS BTWN
00Z-06Z FOR ALL BUT EAST AND SOUTH FRINGES OF CWA. NAM IS QUITE
BULLISH ON POPS FOR OVERNIGHT TONIGHT...MUCH MORE SO THAN OTHER
MODELS. LOOKING AT SOUNDINGS...MOISTURE IS BACK ON THE INCREASE
ALOFT /ROUGHLY ABOVE H7/. LAPSE RATES KIND OF STEEP H7-H5...TOWARD
7C/KM. A LOT OF DRY AIR BLO H7 AND STRONG LIFT LOOKS TO BE LACKING.
MAY SEE A WEAK SHORTWAVE STREAKING OUT AHEAD OF DEEPER WESTERN
CANADA TROUGH WHICH COULD ENHANCE LIFT. KEPT ISOLD MENTION FOR
SHRA/TSRA OVER NORTH TWO-THIRDS OF CWA OUT INTO LK SUPERIOR ALONG
AND NORTH OF H85 FRONT...BUT EVEN THIS POSSIBILITY WILL DIMINISH
LATE IN THE NIGHT AS H7 MOISTURE TRANSPORT WEAKENS AS DOES UVM IN
THE H7-H5 LAYER. SHOULD BE ANOTHER WARM NIGHT /READINGS IN THE 60S/
DUE TO PERSISTENT SOUTH WINDS OUT AHEAD OF SFC LOW DEEPENING OVR
CANADIAN PRAIRIES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 523 AM EDT FRI AUG 24 2012
SATURDAY...AS THE MID LEVEL LOW OVER SASK LIFTS INTO NORTHERN
MANITOBA RIDGING WILL PREVAIL DOWNSTREAM OVER THE GREAT LAKES. AS A
RESULT...DRY MID LEVELS AND CAPPNIG SHOULD LIMIT ANY PCPN
CHANCES...PER ECMWF/GFS. HOWEVER...SINCE THE REGIONAL GEM AND NAM
CONTINUE TO SUGGEST THAT A WEAK SHORTWAVE TROUGH LIFTING OUT OF THE
UPPER MS VALLEY COULD BRING SOME PCPN INTO THE WEST...SLIGHT CHANCE
WAS MENTIONED IN THE LATE AFTERNOON. WITH PLENTY OF SUNSHINE/MIXING
AND 850 MB TEMPS INTO THE 18C-20C RANGE...EXPECT MAX READINGS INTO
THE UPPER 80S WITH A FEW 90S POSSIBLE IN SW FLOW DOWNSLOPE LOCATIONS.
SATURDAY NIGHT AND SUNDAY...THE MODELS SUGGEST THAT THE STRONGER
FORCING AND HEIGHT FALLS AHEAD OF THE MID LEVEL LOW WILL REMAIN
NORTH OF UPPER MICHIGAN WHILE A WEAKER SHORTWAVE MOVING OUT OF THE
CNTRL PLAINS AND GREATER INSTABILITY WILL REMAIN TO THE SOUTH.
SO...THE DRIER QPF FROM THE ECMWF/GEM SCENARIO WAS PREFERRED
COMPARED TO THE GFS. NEVERTHELESS...SCT SHRA/TSRA ARE STILL EXPECTED
AS THE SFC TROUGH AND AXIS OF HIGHER MOISTURE MOVE THROUGH THE CWA.
ANY LINGERING PCPN SHOULD EXIT THE CNTRL CWA SUN EVENING AND THE
EAST OVERNIGHT.
MON-THU...THE MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD
PATTERN AMPLIFICATION AS A TROUGH MOVES INTO THE WRN CONUS AND RIDGE
DEVELOPS FROM THE CNTRL ROCIES INTO THE PLAINS. THE NW FLOW PATTERN
INTO THE UPPER GREAT LAKES WILL BRING A SFC HIGH AND COOLER DRIER
AIR INTO UPPER MI MON-TUE WHICH WOULD GIVE WAY TO WARMING BY
WED-THU. CONFIDENCE IN PCPN POTENTIAL BY WED-THU WITH POTENTIAL
FRONTAL SYSTEM AND HEIGHT FALLS IS LOW GIVEN INCREASING MODEL SPREAD
AND RUN TO RUN VARIATION WITH THE STRENGTH OF THE RIDGE. SO
CONSENSUS SLIGHT CHANCE POPS WERE NOT ALTERED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 125 PM EDT FRI AUG 24 2012
ALTHOUGH THERE COULD BE SOME -SHRA AND EVEN A TS AT SAW THIS AFTN...
EXPECT VFR CONDITIONS AT ALL 3 SITES THRU THIS FCST PERIOD WITH
RELATIVELY DRY LLVL AIR IN PLACE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 523 AM EDT FRI AUG 24 2012
SOUTH TO SOUTHEAST WINDS REMAIN STRONG TODAY ESPECIALLY OVER EASTERN
SECTIONS WHERE GUSTS MAY REACH 25-30 KTS AT HIGHER PLATFORMS AND
SHIP LEVEL. LOW-LEVEL JET AXIS FADES AWAY TONIGHT...SO WINDS SHOULD
DECREASE TO LESS THAN 20 KTS. WINDS EXPECTED TO REMAIN AT 20 KTS OR
LESS THROUGH THE UPCOMING WEEKEND AND INTO EARLY NEXT WEEK AS
STRONGEST PRESSURE GRADIENT STAYS WELL TO NORTH IN THE VICINITY OF
STRONG SFC LOW OVER HUDSON BAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1250 PM CDT FRI AUG 24 2012
.AVIATION...
CONDITIONAL CLIMATOLOLOGY INDICATED THAT STRATUS IN SOUTHWEST
NEBRASKA WILL LIFT AROUND 19Z...AND CEILINGS WILL BE ABOVE THE
MARGINAL VISUAL THRESHOLDS. INSTRUMENT CEILINGS ARE EXPECTED TO
DEVELOP AGAIN OVER NORTH CENTRAL THROUGH SOUTHWEST NEBRASKA AFTER
07Z. THE CEILINGS WILL AGAIN LIFT TO MARGINAL THRESHOLDS IN BBW AND
LBF AFTER 15Z. LATER IN THE MORNING...A FRONT WILL PUSH THE LOW
CEILINGS OUT OF THAT AREA BY 18Z.
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT FRI AUG 24 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
PRIMARY CONCERNS THROUGH THE FIRST FEW DAYS OF THE FORECAST DEAL
WITH TEMPERATURES...CLOUD COVER...AND RAIN CHANCES THROUGH
SATURDAY.
ONGOING STORM COMPLEX BRINGING MUCH NEEDED RAINFALL ACROSS KANSAS
THIS MORNING...SPC MESOANALYSIS SHOWED STRONG MOISTURE ADVECTION
INTO THE STORMS...WHICH WAS ECHOED BY PROFILER DATA WITH 850MB
WINDS OF 35 TO 45KTS INTO THE SYSTEM. ANALYSIS ALSO SHOWED A
STRONG PRECIPITABLE WATER GRADIENT WITH 1.50 TO 2.00 INCHES ACROSS
KANSAS INTO EASTERN NEBRASKA...WHILE THE NORTHERN NEBRASKA
PANHANDLE WAS OBSERVING VALUES LESS THAN THREE QUARTERS OF AN
INCH. ALTHOUGH GOOD RAINFALL WAS OCCURRING OVER KANSAS...THE LOCAL
AREA STAYED DRY OVERNIGHT. THE AREA DID SEE SOME RAIN
YESTERDAY...HOWEVER AMOUNTS WERE LIGHT WITH KLBF BEING THE
WINNER OF THE DAY WITH 0.13 INCHES. THERE IS LIKELY A FEW
LOCATIONS OVER FRONTIER COUNTY THAT MAY HAVE GOTTEN A BIT MORE
RAINFALL DUE TO SOME LATE EVENING THUNDERSTORMS...HOWEVER NO
REPORTED AMOUNTS HAVE BEEN RECEIVED YET.
LOOKING AT WATER VAPOR IMAGERY...A STRONG UPPER LEVEL LOW WAS
SITUATED OVER THE FOUR CORNERS WITH A GOOD FLUX OF MOISTURE
STREAMING NORTHWARD AHEAD OF THIS SYSTEM. THIS HAS BEEN SEEN IN
THE INCREASE OF PRECIPITABLE WATER VALUES AS WAS MENTIONED ABOVE.
ALSO OF NOTE IN THE LARGE SCALE IS A SHORTWAVE TROUGH OVER THE
PACIFIC NORTHWEST...AS WELL AS TROPICAL STORM ISAAC IN THE
CARIBBEAN. CLOSER TO HOME...LOW PRESSURE WAS ANALYZED OVER
SOUTHEAST COLORADO...WITH A SECOND LOW CENTERED OVER EASTERN
MONTANA. SOUTHERLY WINDS WERE BRINGING MOISTURE IN FROM THE
SOUTH...HOWEVER A TIGHT MOISTURE GRADIENT EXISTED WITH DEWPOINTS
RANGING FROM THE 30S IN SOUTHWEST SOUTH DAKOTA TO THE MID AND UPPER
60S FROM SOUTHWEST INTO CENTRAL NEBRASKA.
FOR TODAY...CLOUD COVER WILL HAVE A LARGE IMPACT ON TEMPERATURES.
THERE IS CONSIDERABLE DIFFERENCES IN THE LOW LEVEL MOISTURE FIELDS
FOR THIS MORNING...WITH THE NAM BEING QUITE A BIT DRIER THAN THE
RAP/GFS SOLUTIONS. THE 11-3.9 IR AT 08Z WAS SHOWING THE
FOG/STRATUS EXPANDING QUITE A BIT SO WILL EDGE ON A MORE CLOUDY
FORECAST FOR TODAY. WITH THE MODELS NOT HANDLING THIS WELL HAVE
LOW CONFIDENCE ON HOW FAST THIS MOISTURE WILL SCOUR OUT TODAY.
EARLIER RAP RUNS HAD KEPT THE LOW CLOUDS IN THROUGH MUCH OF THE
DAY...HOWEVER LATEST /24.06Z RUN/ STARTS TO BREAK THINGS OUT
AROUND 18Z. NAM WOULD ALSO HAVE CLOUDS OUT BY 18Z. WITH NO REAL
FOCUS FOR MOISTURE CONVERGENCE THROUGH THE DAY BELIEVE THE LOW CLOUDS
WILL EVENTUALLY DISSIPATE. MAY START TO SEE SOME MID/HIGH LEVEL
CLOUDS MOVING IN THOUGH AT THIS POINT AS BOTH THE UPPER LOW OVER
THE FOUR CORNERS AND THE PACIFIC NORTHWEST SYSTEM MOVE EAST. SO AS
TEMPERATURES SHOULD START TO RECOVER /WITH GOOD WARMING POTENTIAL
IF SEVERAL HOURS OF SUNSHINE ARE REALIZED/ STILL WENT CONSERVATIVE
WITH HIGHS TODAY AND KEPT SOUTHERN AREAS IN THE MID 80S.
SOME MODELS WOULD SUGGEST PRECIPITATION THIS MORNING AND EARLY
AFTERNOON...BUT FROM THE LOOKS OF MOISTURE TRANSPORT
VECTORS...PRECIPITATION SHOULD BE PUSHED TO THE EAST SO KEPT THE
FORECAST THROUGH MID AFTERNOON DRY. BY 25.00Z THE SOUTHERN UPPER
LEVEL SYSTEM WILL BE OVER EASTERN COLORADO...WITH A SURFACE LOW
REMAINING JUST TO ITS EAST. THE LOW LEVEL JET DOES STRENGTHEN
CONSIDERABLY INTO THE EVENING AND OVERNIGHT HOURS...HOWEVER MOST
OF THIS MOISTURE/CONVERGENCE/ENERGY STAYS INTO CENTRAL AND EASTERN
KANSAS AND EASTERN NEBRASKA SO LIMITED RAIN CHANCES TO THE FAR
EASTERN COUNTIES IN THE FORECAST AREA. THIS WAS SUPPORTED BY THE
23.21Z AND 24.03Z SREF RUNS WHICH DID NOT HAVE ANY PROBABILITIES
OF RAINFALL AMOUNTS OVER 0.25 INCH IN THE LOCAL FORECAST AREA.
CONCERNING THE NORTHERN SYSTEM...THE SHORTWAVE WILL BE OVER
SOUTHERN SASKATCHEWAN AT 25.00Z. THIS WILL BRING THE COLD FRONT
INTO THE WESTERN DAKOTAS AND THE NEBRASKA PANHANDLE. KEPT THE
FORECAST DRY OVERNIGHT AS THE FRONT PUSHES EAST...WITH THE
STRONGEST FORCING STAYING WELL TO THE NORTH. THERE IS INDICATIONS
OF SOME MOISTURE CONVERGENCE ALONG THE FRONT OVERNIGHT...SO
WOULDN/T BE SURPRISED TO SEE AN ISOLATED STORM DEVELOP...BUT AGAIN
DIDN/T HAVE THE CONFIDENCE TO ADD CHANCES IN AT THIS POINT.
THE FRONT PUSHES THROUGH THE FORECAST AREA ON SATURDAY...BRINGING
DRIER AND COOLER AIR BEHIND IT. CONVECTION SHOULD CONTINUE
THROUGH THE DAY ALONG THE FRONT. WITH MODELS BEING IN GOOD
AGREEMENT WITH PUSHING THE RAIN EAST OF THE FORECAST AREA...DID
TREND THE FORECAST THAT DIRECTION. DID LEAVE IN SOME SLIGHT
CHANCES IN THE NORTHEASTERN ZONES TO ACCOUNT FOR SLOWER FRONTAL
MOVEMENT OR LINGERING ACTIVITY. DID KEEP TEMPERATURES AHEAD OF THE
FRONT LOWER AS THE FRONT WILL PUSH THROUGH BEFORE AFTERNOON
HEATING SETS IN...AS WELL AS THE THOUGHT THAT THERE MAY AGAIN BE A
BATCH OF STRATUS IN THESE AREAS IN THE MORNING. ALTHOUGH
TEMPERATURES WILL BE COOLER ON SATURDAY...WITH HIGHS IN THE
80S...DEWPOINTS LOOK TO DROP INTO THE 30S BEHIND THE FRONT. THIS
WILL DROP RELATIVE HUMIDITY TO AROUND 20 PERCENT IN THE AFTERNOON.
ALSO EXPECTING BREEZY NORTHERLY WINDS BEHIND THE FRONT. ALTHOUGH
DON/T ANTICIPATE NEEDING HEADLINES FOR FIRE WEATHER...WILL NEED TO
KEEP THIS IN MIND AS FIRE WEATHER CONDITIONS WILL BE NEAR
CRITICAL.
SATURDAY NIGHT THROUGH SUNDAY NIGHT SHOULD BE FAIRLY QUIET AS
UPPER LEVEL RIDGING STARTS TO BUILD IN AS THE SHORTWAVES EXIT TO
THE EAST. SKIES SHOULD CLEAR THROUGH THE PERIOD WITH HIGH PRESSURE
SETTLING IN. COULD SEE TEMPERATURES DROP DOWN INTO THE 50S OVER
MUCH OF THE AREA SATURDAY NIGHT...DUE TO GOOD RADIATIONAL COOLING.
LONG TERM...MONDAY THROUGH THURSDAY
NO BIG CONCERNS TO DEAL WITH THROUGH THIS PORTION OF THE FORECAST.
THE UPPER LEVEL RIDGE BUILDS IN...SO ANOTHER WARMING TREND IS
EXPECTED WITH HIGHS IN THE UPPER 80S AND 90S THROUGH MUCH OF THE
WEEK. NO GOOD CHANCES FOR RAIN EXIST...ALTHOUGH THERE MAY BE
STORMS TOPPING THE RIDGE TO IMPACT NORTHERN NEBRASKA. WITH VERY
LITTLE CONFIDENCE ON WHEN AND WHERE THESE STORMS WILL DEVELOP KEPT
THE FORECAST DRY THROUGHOUT THIS TIME. WITH THE DRY
CONDITIONS...AND WITH A LACK OF MOISTURE BEING BROUGHT
NORTH...WILL EXPECT LARGE TEMPERATURE SWINGS SO ALTHOUGH HIGHS
WILL BE IN THE 90S...STILL LOOKING AT LOWS IN THE 50S AND LOW 60S
MOST NIGHTS.
EYES CONTINUE TO WATCH TROPICAL STORM ISAAC...WHICH IS WELL OUT IN
THE CARIBBEAN CURRENTLY. LONG TERM MODELS COMING INTO MORE
AGREEMENT IN SOLUTIONS...BRINGING IT ONSHORE NEAR MOBILE ALABAMA
THEN PUSHING NORTHWARD INTO THE OHIO RIVER VALLEY BEFORE BEING
CAUGHT UP IN THE FLOW AND SHUNTED EAST. THIS WOULD PROVIDE NO HELP
TO THE LOCAL AREA IN TERMS OF MOISTURE UNFORTUNATELY. THIS IS ALL
TO OCCUR NEXT WEEKEND AND THE NEXT WEEK SO THINGS COULD CERTAINLY
CHANGE BEFORE THEN AND WILL BE WATCHING TO SEE IF THERE MAY BE ANY
IMPACT LOCALLY FROM THIS STORM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1153 AM MDT FRI AUG 24 2012
.AVIATION...
18Z TAF CYCLE
ANOTHER ACTIVE SHOWER AND STORM DAY ALTHOUGH THE FOOTPRINT OF MVFR
CONDITIONS ASSOCIATED WITH THE STRONGER STORMS SHOULD BE A BIT
LESS. SANTA FE CURRENTLY HAS SH/TS AROUND THE GREATER AREA SO WENT
BULLISH FOR THAT LOCATION IN THE TEMPO GROUP. ALSO HAVE TEMPO/S IN
FOR FMN...GUP AND ABQ AS THE UPPER LOW PIVOTS EASTWARD OVER
SOUTHERN COLORADO AND NORTHERN NEW MEXICO. GOING WITH VCSH AT LVS
AND WILL WATCH THE SHOWER TRENDS AT THAT LOCATION. NORTHERLY WIND
SHIFT EXPECTED ACROSS THE EASTERN PLAINS TONIGHT BUT NOT LOOKING
AT A LOT OF WIND SPEED BEHIND IT.
50
&&
.PREV DISCUSSION...603 AM MDT FRI AUG 24 2012...
.AVIATION...
UPPER LEVEL LOW TO TRACK ACROSS SOUTHERN COLORADO TODAY...
SUPPORTING A WEST TO EAST MOIST FLOW ACROSS NORTHERN AND WESTERN
ZONES. SOME PATCHY LOW CLOUDS WILL DEVELOP EAST OF THE CENTRAL
MOUNTAINS THIS MORNING...GENERALLY FROM KCQC SOUTH TO NEAR
KSRR. MID AND HIGH LEVEL CLOUDS ALREADY IN PLACE WILL GIVE WAY TO
ISOLATED TO SCATTERED THUNDERSTORMS AND SHOWERS MAINLY OVER THE
HIGHER TERRAIN...WITH THE NORTH CENTRAL MOUNTAINS POTENTIALLY
SEEING MORE ACTIVITY...MAINLY FROM 17Z THROUGH 03Z. THUNDERSTORMS
WILL RESULT IN MFVR CIGS AND VISIBILITIES IN RAIN OR HEAVY RAIN AT
TIMES AS WELL AS SOME MOUNTAIN TOP OBSCURATIONS. MOSTLY MID LEVEL
CLOUDS TO PERSIST AFTER 03Z THROUGH REMAINDER OF PERIOD.
05
.PREV DISCUSSION...300 AM MDT FRI AUG 24 2012...
UPPER LOW CIRCULATION NEAR KFMN EARLY THIS MORNING. RUC OPENS IT UP
BY MIDDAY WHILE FORECAST POSITION WILL BE OVER NRN MTS. GFS SEEMS TO
MOVE THE TROUGH A LITTLE FASTER THAN 24 HOURS AGO WHILE NAM
INDICATES SOME HANG BACK ENERGY WHICH RETARDS EASTWARD PROGRESS AND
THEREFORE THE TROUGHS EXIT UNTIL LATE SATURDAY AFTERNOON.
NONETHELESS...MOISTURE WILL REMAIN IN PLACE TODAY AND TONIGHT
ESPECIALLY AOB H5 WHILE MODELS AND SATELLITE IMAGERY INDICATE DRYING
IN THE UPPER LEVELS OF THE ATMOSPHERE. UPSLOPE WINDS SHOULD FAVOR
CONVECTION OVER THE WESTERN/NORTHERN MOUNTAINS TODAY AND WITH WIND
SHIFT IN THE NORTHEAST...THE FOCUS FOR RAIN MAY LIKELY SHIFT INTO
THAT REGION LATER THIS AFTERNOON/EVENING WITH THE UPPER TROUGH
NEARING. TEMPERATURES TODAY STILL A BIT ON THE LOWER SIDE OF AVERAGE
CENTRAL AND WEST...BUT A LITTLE ABOVE IN THE EAST.
SATURDAY WILL BE A TRANSITION DAY AS THE TROUGH EXITS AND AN
EASTERLY LOW LEVEL GRADIENT SETS UP OVER EASTERN NEW MEXICO. THERE
MAY BE SOME POTENTIAL FOR AN EAST WIND INTO THE RGV SATURDAY
NIGHT...BUT THIS APPEARS MORE LIKELY SUNDAY/SUNDAY NIGHT AS THE
UPPER HIGH CENTER SETS UP SHOP OVER NRN NM/SRN CO. WHILE LOW LEVEL
MOISTURE MAY START TO DRY/MIX OUT IN THE FAR NORTHWEST...THE
BOUNDARY LAYER WINDS SHOULD KEEP DEWPOINTS FROM CRATERING IN THE
EAST. TEMPERATURE WISE...MOST AREAS SHOULD BE A FEW DEGREES WARMER
THAN AVERAGE DURING THE DAY BY MONDAY...WHILE MINS GENERALLY STAY
ABOVE NORMAL FOR THE NEXT SEVERAL DAYS.
BY MID TO LATE NEXT WEEK...FORECAST MODELS CONTINUE TO HAVE TROUBLE
RESOLVING THE STRENGTH OF THE UPPER HIGH AND THE LOCATION AND
STRENGTH OF THE WESTERLIES OVER THE NORTHERN/CENTRAL TIER OF THE
WESTERN U.S. CONFIDENCE NOT ALL THAT GREAT IN ONE SCENARIO VS
ANOTHER SO GENERIC AFTERNOON/EVENING SHOWERS AND STORMS FAVORING THE
HIGHER TERRAIN SEEMS BEST FOR NOW.
.FIRE WEATHER...
WEAK UPPER LEVEL DISTURBANCE IS CURRENTLY CENTERED NEAR THE FOUR
CORNERS WITH MID AND UPPER LEVEL DRY SLOT WORKING INTO CENTRAL NEW
MEXICO. SURFACE DEWPOINTS DECREASING AS WELL ESPECIALLY WEST AND
CENTRAL ZONES. THE UPPER WAVE WILL MOVE TO THE EAST DURING THE DAY
WITH WETTING RAIN FAVORING THE WESTERN AND NORTHERN ZONES WITH
BREEZY WEST WINDS DEVELOPING THIS AFTERNOON ACROSS THE EAST CENTRAL
PLAINS. TEMPS WARM A BIT MOST ZONES WITH SUBSTANTIAL DECREASES IN
AFTERNOON RH VALUES.
HIGH PRESSURE BUILDS IN THE WAKE OF THE UPPER LEVEL DISTURBANCE WITH
A RIDGE AXIS NEAR THE FOUR CORNERS BY MID DAY SATURDAY SUPPORTING
ADDITIONAL WARMING AND DRYING ACROSS WESTERN AND NORTHCENTRAL ZONES.
SUFFICIENT MOISTURE PERSISTS AT THE SURFACE TO SUPPORT SCATTERED
THUNDERSTORMS OVER THE HIGHER TERRAIN WITH ISOLATED COVERAGE
ELSEWHERE. A BACK DOOR FRONT WILL PUSH INTO THE NORTHEAST LATE ON
SATURDAY AND THROUGH THE EAST PLAINS ON SUNDAY AS THE UPPER HIGH
CENTERS OVER NEW MEXICO. MODERATE GAP WINDS WERE ADDED TO THE GRIDS
FOR SATURDAY NIGHT...AND DEPENDING ON THE STRENGTH OF THE EAST WINDS
SURFACE MOISTURE INCREASES COULD MAKE IT TO THE CONTINENTAL DIVIDE.
WETTING RAINS ON SUNDAY LOOK TO FAVOR THE CENTRAL HIGH TERRAIN AND
ADJACENT EAST SLOPES WITH AN UPTICK IN COVERAGE OVER THE WESTERN
TERRAIN.
MODELS GENERALLY AGREE ON BUILDING THE UPPER HIGH EARLY IN THE WORK
WEEK WITH POSSIBLY A SLIGHT SHIFT TO THE EAST. A MONSOON PLUME WORKS
AROUND THE WESTERN EDGE OF THE HIGH...BUT THE FOCUS REMAINS OVER
MEXICO. THE EASTERN PLAINS LOOK TO BE DRIER WITH PRECIPITATION
SHIFTING TO THE WEST. THE RIDGE LOOKS TO WEAKER LATER IN THE WEEK
WITH A GENERAL DECREASE IN RELATIVE HUMIDITIES AND WETTING RAIN MOST
LOCATIONS.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
624 PM EDT FRI AUG 24 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE SLOWLY UP THE CAROLINA COAST OVERNIGHT.
HIGH PRESSURE WILL BUILD SOUTH THIS WEEKEND...BRINGING SLIGHTLY
DRIER AIR INTO THE REGION. TROPICAL STORM ISAAC IS EXPECTED TO
MOVE INTO THE EASTERN GULF OF MEXICO EARLY NEXT WEEK. REMNANTS
OF ISAAC COULD BRING UNSETTLED WEATHER TO THE CAROLINAS BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 PM FRIDAY...MID TO UPPER LOW WILL TRACK UP THE SOUTHEAST
COAST THROUGH TONIGHT. THE H5 CIRCULATION REMAINS BROAD WITH
CENTER TIGHTENING A BIT OVERNIGHT WITH CENTER FORECAST OVER NC/VA
BORDER BY SAT MORNING. THE ASSOCIATED SURFACE LOW JUST E-SE OF
CAPE FEAR THIS AFTERNOON WILL MOVE NORTH AND BECOME MORE ELONGATED
AS IT WEAKENS THROUGH TONIGHT. NAM STILL SHOWING BEST ENERGY
ASSOCIATED WITH THIS LOW TO MOVE FROM COASTAL WATERS JUST SOUTH OF
CAPE FEAR DUE NORTH INTO NC THIS AFTERNOON. HRRR MODEL SHOWING
BEST CHC FOR HEAVIER PCP FROM THE TIP OF CAPE FEAR NORTH ALONG THE
NORTH CAROLINA COAST MAINLY FROM NEW HANOVER COUNTY THROUGH PENDER
COUNTY. THE BEST CHC OF HEAVIER PCP WILL OCCUR DURING THIS TIME
BUT BULLSEYE FOR HEAVIEST RAIN IN TSTMS WILL REMAIN OVER THE
WATERS TO THE EAST. THE GREATEST THREAT THROUGH WILL BE POTENTIAL
FOR FLOODING AS STEERING FLOW OVER MOST LAND AREAS WILL REMAIN
VERY WEAK. PCP WATER VALUES WILL REMAIN AROUND 2 INCHES UP THE
CAPE FEAR COAST DROPPING OFF AS YOU MOVE INLAND DOWN LESS THAN AN
INCH IN DRIER AIR AND SUBSIDENCE ON BACK END OF LOW WEST OF LOCAL
CWA...OVER CENTRAL TO WESTERN CAROLINAS. WILL KEEP LOW END POPS
INLAND AS SOME ENERGY ROTATES AROUND THE LOW...BUT OVERALL CLOUDS
AND COOLER NORTHERLY FLOW KEEPING TEMPS JUST AROUND 80 AND OVERALL
MORE STABLE ATMOSPHERE.
MODEL SOUNDINGS AND MOISTURE PROFILES SHOWING DRIER AIR WORKING
ITS WAY IN ON THE BACK EDGE OF LOW THROUGH THE MID TO UPPER
LEVELS TONIGHT AS IT LIFTS OFF TO THE NORTH. THIS WILL HELP PCP
SHUT OFF OVER LOCAL AREA. NAM SHOWS PCP WATER VALUES DROPPING
DOWN LESS THAN 1.5 INCHES BY SAT MORNING. CLOUDS...PCP AND FOG
WILL HELP KEEP TEMPS IN THE MID 60S AND CLOSER TO 70 WHERE GREATER
DEWPOINT AIR WILL HANG ON THE LATEST. MAY SEE STRATUS DEVELOP AS
MOISTURE BECOMES TRAPPED UNDER LOW LEVEL INVERSION...MORE PROBABLE
CLOSER TO THE COAST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 340 PM FRIDAY...A DRIER PATTERN ANTICIPATED THIS WEEKEND...AS
DRY MID-LEVEL AIR OVERSPREADS THE REGION...AND A SURFACE LOW PULLS
SLUGGISHLY NORTH AND AWAY FROM OUR AREA. WEAK UPPER LOW POSITIONED
JUST NORTH OF OUR AREA SATURDAY AND SUNDAY WILL CONTINUE TO FEED
DRY AIR ALOFT...BUT CONCURRENTLY SHOULD PROMPT PLENTY OF DIURNAL
BUT MOSTLY CAPPED CUMULUS. CONVERGENCE OFFSHORE LATE IN THE PERIOD
MAY BRING COASTAL SHOWERS SUNDAY NIGHT. WHILE A SHOWER CANNOT BE
RULED OUT ON THE SEA BREEZE FRONT THIS WEEKEND...ACTIVITY SHOULD
IN OR BELOW THE ISOLATED CATEGORY.
MAXIMUM TEMPS WITH PARTIAL CLOUDS AND HIGH PRESSURE WEDGED IN FROM
THE NORTH...SHOULD RESULT IN MAINLY MIDDLE AND UPPER 80S BOTH DAYS.
MINIMUM TEMPS WILL DIP BELOW 70 MOST LOCATIONS BY DAYBREAK SAT/SUN
BUT QUITE A BIT MORE MILD AT THE COAST IN ONSHORE WIND DIRECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 340 PM FRIDAY...SENSIBLE WEATHER THROUGH THE EXTENDED WILL
DEPEND ALMOST ENTIRELY ON ISAAC AND HIS POTENTIAL IMPACTS TO THE
REGION. STILL CONSIDERABLE UNCERTAINTY DUE TO TRACK
FORECASTS...WHICH...UNFORTUNATELY...WILL CREATE SIGNIFICANT
DIFFERENCES IN THE WEATHER ACROSS THE ILM CWA.
GFS/CMC ARE IN DECENT AGREEMENT WITH THEIR OVERALL EVOLUTION OF
ISAAC WHEN COMPARED TO THE ECMWF WHICH IS THE OUTLIER OF THE THREE
MODELS. WHILE THE ECMWF SLOWLY BRINGS ISAAC UP THROUGH THE GULF
COAST AND MEANDERS IT NW INTO THE TN VLY THROUGH MIDWEEK BEFORE
DISSIPATING...THE GFS/CMC BRING IT SLIGHTLY FURTHER EAST INTO THE
PANHANDLE OF FLORIDA ON TUESDAY AND THEN MAKE A SHARP
RECURVE...MOVING ISAAC`S REMNANTS BASICALLY OVER THE ILM CWA ON
WEDNESDAY. WILL LEAN TOWARDS THE GFS/CMC CONSENSUS...THE THINKING
THAT THE LARGE RIDGE WHICH FORCES THE ECMWF SOLUTION TO REMAIN WEST
IS OVERDONE. THIS MEANS DEEP S/SE FLOW MON/TUE WHICH SHOULD SUPPORT
ADVECTION SHOWERS...ESPECIALLY NEAR THE COAST...AND THEN A MUCH
WETTER DAY WEDNESDAY AS MID LEVEL THETA-E RIDGE ASSOCIATED WITH
ISAAC AND ITS REMNANTS...MOVES OVERHEAD. BY THURSDAY WE SHOULD BE ON
THE DRY WEST SUBSIDENT SIDE OF THE STORM AND WILL DRY OUT FOR LATE
WEEK. STILL MUCH UNCERTAINTY...BUT WILL RAMP POP UPWARDS THROUGH
WEDNESDAY BEFORE RAPIDLY TAILING OFF ON THURSDAY/FRIDAY.
NOTE THAT CURRENT FORECAST IS AT LEAST SLIGHTLY DIFFERENT THAN
HPC/NHC WHICH IS FAVORING A MUCH MORE WESTERN AND SLOWER
TRACK...ECMWF...FOR ISAAC. IF THE ECMWF TRACK WERE TO
VERIFY...WEDNESDAY WOULD STILL BE THE WETTEST DAY...SO POP TRENDS
WOULD STILL BE CORRECT...BUT OVERALL LESS RAINFALL ALONG WITH SLOWER
DECREASE IN POP WOULD BE NEEDED IN THAT SOLUTION (I.E. BETTER RAIN
CHANCES CONTINUING THROUGH THE END OF THE WEEK). WILL HAVE TO
MONITOR GUIDANCE TRENDS AND MODIFY FURTHER FORECAST UPDATES AS
NEEDED.
TEMPS WILL BE AROUND CLIMO MOST DAYS...WARMING TO ABOVE BY THE END
OF THE WEEK.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...WET PATTERN FINALLY IS BREAKING AS A FAIRLY STRONG VORT
PULLS NORTHEAST...TAKING THE FRONT WITH IT. THE MODERATE TO HEAVY
PRECIP ALONG THE COAST TODAY WILL LIKELY CONTRIBUTE TO IFR
CONDITIONS AT THE COASTAL TERMINALS SOMETIME AFTER MIDNIGHT. THE
INLAND TERMINALS ARE A BIT MORE UNCERTAIN. THERE IS NOT AS MUCH LOW
LEVEL MOISTURE...BUT RADIATIONAL COOLING CONDITIONS ARE REASONABLY
GOOD...AND THE TMP/DPT SPREAD IS NOT MUCH TO BEGIN WITH. LIKEWISE A
LIGHT NORTHEAST WIND IS FAVORABLE. WILL STICK WITH MVFR AT THIS TIME
BUT WILL MONITOR CLOSELY. SATURDAY...A GREAT DAY TO BE OUTSIDE WITH
MODERATE TEMPERATURES AND A NOTICEABLY DRIER ATMOSPHERE. CONTINUED LIGHT
NORTHEAST FLOW...WITH VFR CONDITIONS EXPECTED BY 15Z...CONTINUING
THROUGH THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...ISOLATED SHRA/TSRA MON. BETTER CHANCE OF SHOWERS
AND STORMS TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 340 PM FRIDAY...MID TO UPPER LOW MOVE UP INTO NORTH CAROLINA
WITH CENTER REACHING THE NC/VA BORDER BY MORNING. AT THE SAME TIME
AN ASSOCIATED AREA OF LOW PRESSURE WILL TRACK SLOWLY UP THROUGH THE
LOCAL COASTAL WATERS REACHING TOWARD HATTERAS AFTER MIDNIGHT.
THIS WILL HELP TO PRODUCE MORE WIDESPREAD PRECIPITATION IN
SHWRS/TSTMS THROUGH THIS EVENING...WINDING DOWN FROM S TO N TONIGHT.
SFC WINDS 10 TO 15 KTS WILL DIMINISH A BIT OVERNIGHT AS THEY BACK
TOWARD THE NW. THIS OFF SHORE FLOW WILL ACT TO LOWER SEAS BUT A
LONGER PERIOD E-SE SWELL UP TO 16 SECONDS WILL COUNTERACT THIS OFF
SHORE FLOW AND WILL PRODUCE A SLIGHT INCREASE IN OVERALL SEAS
OVERNIGHT. SEAS WILL BUILD TO 3 TO 4 FT MAINLY ACROSS THE OUTER
WATERS. EXPECT ROUGHER SEAS WITH HIGHER WINDS AND SEAS IN TSTMS
THROUGH THIS EVENING AND ALSO REDUCED VSBYS DUE TO HEAVY RAIN. RADAR
CONTINUED TO SHOW THE POSSIBILITY OF WATERSPOUTS IN STORMS OVER THE
OUTER COASTAL WATERS THIS AFTERNOON.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 340 PM FRIDAY...OUTSIDE OF TSTMS WINDS WILL REMAIN MANAGEABLE
SATURDAY AND SUNDAY...AS A SURFACE LOW OVER THE WATERS MOVES
SLOWLY NORTH OF THE AREA. WINDS WILL VEER EAST SUNDAY AS HIGH
PRESSURE CONSOLIDATES OVER NEW ENGLAND. THE COMBINATION OF WIND-
WAVES AND SWELL WAVES WILL KEEP SEAS MAINLY 3-4 FEET THIS WEEKEND
AND UP TO 5 FEET AT TIMES WELL OFFSHORE. NUMEROUS SHOWERS AND
TSTMS WILL BECOME SCATTERED TO ISOLATED THIS WEEKEND...AS THE SFC
LOW PULLS NORTH OF SURF CITY BY DAYBREAK SATURDAY...AND DRY AIR
ALOFT HELPS TO SQUELCH STORM DEVELOPMENT.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 340 PM FRIDAY...QUITE A BIT OF UNCERTAINTY THROUGH THE
EXTENDED AS WIND/WAVE CONDITIONS COULD VARY CONSIDERABLY DEPENDING
ON WHAT HAPPENS WITH TS ISAAC. ANTICIPATE E/SE WINDS MON THROUGH TUE
AS ISAAC MOVES ALONG THE WEST COAST OF FLORIDA AND INTO THE GULF
COAST REGION. THE CONTINUED E/SE WINDS AROUND 10 KTS...UP TO 15 KTS
ACROSS THE SOUTHERN WATERS...WILL GENERATE 2-4 FT SOUTHERLY WIND
WAVES. THESE WIND WAVES WILL COMBINE WITH WHAT SHOULD BE INCREASING
S/SE SWELL OF 4-5FT/9SEC DUE TO TROPICAL SYSTEMS ISAAC AND JOYCE.
GUIDANCE IS NOT VERY ROBUST IN DEVELOPING ANY SIGNIFICANT VERY LONG
PERIOD SWELL...BUT NEVERTHELESS...3-5 FT SEAS ARE EXPECTED THROUGH
TUESDAY...WITH 6 FOOTERS POSSIBLE ACROSS THE SOUTHERN WATERS. SEAS
COULD BUILD MUCH HIGHER WEDNESDAY...ESPECIALLY IF GFS/CMC ARE
CORRECT...DUE TO INCREASING SOUTHERLY WINDS...AND SMALL CRAFT
ADVISORY CONDITIONS WILL BE POSSIBLE AT THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
343 PM EDT FRI AUG 24 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE SLOWLY UP THE CAROLINA COAST OVERNIGHT.
HIGH PRESSURE WILL BUILD SOUTH THIS WEEKEND...BRINGING SLIGHTLY
DRIER AIR INTO THE REGION. TROPICAL STORM ISAAC IS EXPECTED TO
MOVE INTO THE EASTERN GULF OF MEXICO EARLY NEXT WEEK. REMNANTS
OF ISAAC COULD BRING UNSETTLED WEATHER TO THE CAROLINAS BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 PM FRIDAY...MID TO UPPER LOW WILL TRACK UP THE SOUTHEAST
COAST THROUGH TONIGHT. THE H5 CIRCULATION REMAINS BROAD WITH
CENTER TIGHTENING A BIT OVERNIGHT WITH CENTER FORECAST OVER NC/VA
BORDER BY SAT MORNING. THE ASSOCIATED SURFACE LOW JUST E-SE OF
CAPE FEAR THIS AFTERNOON WILL MOVE NORTH AND BECOME MORE ELONGATED
AS IT WEAKENS THROUGH TONIGHT. NAM STILL SHOWING BEST ENERGY
ASSOCIATED WITH THIS LOW TO MOVE FROM COASTAL WATERS JUST SOUTH OF
CAPE FEAR DUE NORTH INTO NC THIS AFTERNOON. HRRR MODEL SHOWING
BEST CHC FOR HEAVIER PCP FROM THE TIP OF CAPE FEAR NORTH ALONG THE
NORTH CAROLINA COAST MAINLY FROM NEW HANOVER COUNTY THROUGH PENDER
COUNTY. THE BEST CHC OF HEAVIER PCP WILL OCCUR DURING THIS TIME
BUT BULLSEYE FOR HEAVIEST RAIN IN TSTMS WILL REMAIN OVER THE
WATERS TO THE EAST. THE GREATEST THREAT THROUGH WILL BE POTENTIAL
FOR FLOODING AS STEERING FLOW OVER MOST LAND AREAS WILL REMAIN
VERY WEAK. PCP WATER VALUES WILL REMAIN AROUND 2 INCHES UP THE
CAPE FEAR COAST DROPPING OFF AS YOU MOVE INLAND DOWN LESS THAN AN
INCH IN DRIER AIR AND SUBSIDENCE ON BACK END OF LOW WEST OF LOCAL
CWA...OVER CENTRAL TO WESTERN CAROLINAS. WILL KEEP LOW END POPS
INLAND AS SOME ENERGY ROTATES AROUND THE LOW...BUT OVERALL CLOUDS
AND COOLER NORTHERLY FLOW KEEPING TEMPS JUST AROUND 80 AND OVERALL
MORE STABLE ATMOSPHERE.
MODEL SOUNDINGS AND MOISTURE PROFILES SHOWING DRIER AIR WORKING
ITS WAY IN ON THE BACK EDGE OF LOW THROUGH THE MID TO UPPER
LEVELS TONIGHT AS IT LIFTS OFF TO THE NORTH. THIS WILL HELP PCP
SHUT OFF OVER LOCAL AREA. NAM SHOWS PCP WATER VALUES DROPPING
DOWN LESS THAN 1.5 INCHES BY SAT MORNING. CLOUDS...PCP AND FOG
WILL HELP KEEP TEMPS IN THE MID 60S AND CLOSER TO 70 WHERE GREATER
DEWPOINT AIR WILL HANG ON THE LATEST. MAY SEE STRATUS DEVELOP AS
MOISTURE BECOMES TRAPPED UNDER LOW LEVEL INVERSION...MORE PROBABLE
CLOSER TO THE COAST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 340 PM FRIDAY...A DRIER PATTERN ANTICIPATED THIS WEEKEND...AS
DRY MID-LEVEL AIR OVERSPREADS THE REGION...AND A SURFACE LOW PULLS
SLUGGISHLY NORTH AND AWAY FROM OUR AREA. WEAK UPPER LOW POSITIONED
JUST NORTH OF OUR AREA SATURDAY AND SUNDAY WILL CONTINUE TO FEED
DRY AIR ALOFT...BUT CONCURRENTLY SHOULD PROMPT PLENTY OF DIURNAL
BUT MOSTLY CAPPED CUMULUS. CONVERGENCE OFFSHORE LATE IN THE PERIOD
MAY BRING COASTAL SHOWERS SUNDAY NIGHT. WHILE A SHOWER CANNOT BE
RULED OUT ON THE SEA BREEZE FRONT THIS WEEKEND...ACTIVITY SHOULD
IN OR BELOW THE ISOLATED CATEGORY.
MAXIMUM TEMPS WITH PARTIAL CLOUDS AND HIGH PRESSURE WEDGED IN FROM
THE NORTH...SHOULD RESULT IN MAINLY MIDDLE AND UPPER 80S BOTH DAYS.
MINIMUM TEMPS WILL DIP BELOW 70 MOST LOCATIONS BY DAYBREAK SAT/SUN
BUT QUITE A BIT MORE MILD AT THE COAST IN ONSHORE WIND DIRECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 340 PM FRIDAY...SENSIBLE WEATHER THROUGH THE EXTENDED WILL
DEPEND ALMOST ENTIRELY ON ISAAC AND HIS POTENTIAL IMPACTS TO THE
REGION. STILL CONSIDERABLE UNCERTAINTY DUE TO TRACK
FORECASTS...WHICH...UNFORTUNATELY...WILL CREATE SIGNIFICANT
DIFFERENCES IN THE WEATHER ACROSS THE ILM CWA.
GFS/CMC ARE IN DECENT AGREEMENT WITH THEIR OVERALL EVOLUTION OF
ISAAC WHEN COMPARED TO THE ECMWF WHICH IS THE OUTLIER OF THE THREE
MODELS. WHILE THE ECMWF SLOWLY BRINGS ISAAC UP THROUGH THE GULF
COAST AND MEANDERS IT NW INTO THE TN VLY THROUGH MIDWEEK BEFORE
DISSIPATING...THE GFS/CMC BRING IT SLIGHTLY FURTHER EAST INTO THE
PANHANDLE OF FLORIDA ON TUESDAY AND THEN MAKE A SHARP
RECURVE...MOVING ISAAC`S REMNANTS BASICALLY OVER THE ILM CWA ON
WEDNESDAY. WILL LEAN TOWARDS THE GFS/CMC CONSENSUS...THE THINKING
THAT THE LARGE RIDGE WHICH FORCES THE ECMWF SOLUTION TO REMAIN WEST
IS OVERDONE. THIS MEANS DEEP S/SE FLOW MON/TUE WHICH SHOULD SUPPORT
ADVECTION SHOWERS...ESPECIALLY NEAR THE COAST...AND THEN A MUCH
WETTER DAY WEDNESDAY AS MID LEVEL THETA-E RIDGE ASSOCIATED WITH
ISAAC AND ITS REMNANTS...MOVES OVERHEAD. BY THURSDAY WE SHOULD BE ON
THE DRY WEST SUBSIDENT SIDE OF THE STORM AND WILL DRY OUT FOR LATE
WEEK. STILL MUCH UNCERTAINTY...BUT WILL RAMP POP UPWARDS THROUGH
WEDNESDAY BEFORE RAPIDLY TAILING OFF ON THURSDAY/FRIDAY.
NOTE THAT CURRENT FORECAST IS AT LEAST SLIGHTLY DIFFERENT THAN
HPC/NHC WHICH IS FAVORING A MUCH MORE WESTERN AND SLOWER
TRACK...ECMWF...FOR ISAAC. IF THE ECMWF TRACK WERE TO
VERIFY...WEDNESDAY WOULD STILL BE THE WETTEST DAY...SO POP TRENDS
WOULD STILL BE CORRECT...BUT OVERALL LESS RAINFALL ALONG WITH SLOWER
DECREASE IN POP WOULD BE NEEDED IN THAT SOLUTION (I.E. BETTER RAIN
CHANCES CONTINUING THROUGH THE END OF THE WEEK). WILL HAVE TO
MONITOR GUIDANCE TRENDS AND MODIFY FURTHER FORECAST UPDATES AS
NEEDED.
TEMPS WILL BE AROUND CLIMO MOST DAYS...WARMING TO ABOVE BY THE END
OF THE WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AS OF 19Z...A STATIONARY FRONT IS LOCATED OFFSHORE WITH NE FLOW
IN THE LOW-LEVELS ACROSS THE TERMS. IFR CIGS ARE OCCURRING FROM
MYR S...WITH MVFR CEILINGS ACROSS THE REMAINING TERMS. WIDESPREAD
LIGHT TO OCCASIONALLY MODERATE RAIN IS OCCURRING...AND SO FAR ANY
THUNDERSTORMS HAVE REMAIN OFFSHORE. LOW PRESSURE IS CLEARLY SEEN
IN RADAR LOOPS SE OF CHS MOVING NE.
THINK THUNDERSTORMS WILL REMAIN CLOSEST TO THE ADVANCING LOW PRES.
THIS SHOULD KEEP BEST THUNDERSTORM POTENTIAL OFFSHORE TO SOUTHEAST
OF CRE/MYR...WITH THUNDERSTORMS MOST LIKELY AFFECTING ILM WITH AT
LEAST VCTS AFT 19-20Z. THROUGH 22Z TEMPO MVFR CONDITIONS COULD
OCCUR AT FLO/LBT...WITH MVFR/TEMPO IFR AT CRE/MYR. ILM TERMINAL
SHOULD HAVE THE BEST POTENTIAL FOR IFR THIS AFTERNOON...BUT IF
THE LOW PASSES TOO FAR OFFSHORE...THEN VCTS/IFR WOULD BE LESS
LIKELY.
PRECIPITATION WILL SLOWLY DECREASE AND BY EVENING SHOULD BE
NORTHEAST OF FLO/MYR/CRE AND BY LATE EVENING NORTHEAST OF ALL THE
TERMINALS. SUBSIDENCE IN THE WAKE OF THE PRECIPITATION SHOULD ALLOW
FOR A A GOOD CHANCE OF MVFR VSBYS DEVELOPING AT ALL TERMINALS...AND
IFR CIGS AT THE COASTAL TERMINALS OVERNIGHT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 340 PM FRIDAY...MID TO UPPER LOW MOVE UP INTO NORTH CAROLINA
WITH CENTER REACHING THE NC/VA BORDER BY MORNING. AT THE SAME TIME
AN ASSOCIATED AREA OF LOW PRESSURE WILL TRACK SLOWLY UP THROUGH THE
LOCAL COASTAL WATERS REACHING TOWARD HATTERAS AFTER MIDNIGHT.
THIS WILL HELP TO PRODUCE MORE WIDESPREAD PRECIPITATION IN
SHWRS/TSTMS THROUGH THIS EVENING...WINDING DOWN FROM S TO N TONIGHT.
SFC WINDS 10 TO 15 KTS WILL DIMINISH A BIT OVERNIGHT AS THEY BACK
TOWARD THE NW. THIS OFF SHORE FLOW WILL ACT TO LOWER SEAS BUT A
LONGER PERIOD E-SE SWELL UP TO 16 SECONDS WILL COUNTERACT THIS OFF
SHORE FLOW AND WILL PRODUCE A SLIGHT INCREASE IN OVERALL SEAS
OVERNIGHT. SEAS WILL BUILD TO 3 TO 4 FT MAINLY ACROSS THE OUTER
WATERS. EXPECT ROUGHER SEAS WITH HIGHER WINDS AND SEAS IN TSTMS
THROUGH THIS EVENING AND ALSO REDUCED VSBYS DUE TO HEAVY RAIN. RADAR
CONTINUED TO SHOW THE POSSIBILITY OF WATERSPOUTS IN STORMS OVER THE
OUTER COASTAL WATERS THIS AFTERNOON.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 340 PM FRIDAY...OUTSIDE OF TSTMS WINDS WILL REMAIN MANAGEABLE
SATURDAY AND SUNDAY...AS A SURFACE LOW OVER THE WATERS MOVES
SLOWLY NORTH OF THE AREA. WINDS WILL VEER EAST SUNDAY AS HIGH
PRESSURE CONSOLIDATES OVER NEW ENGLAND. THE COMBINATION OF WIND-
WAVES AND SWELL WAVES WILL KEEP SEAS MAINLY 3-4 FEET THIS WEEKEND
AND UP TO 5 FEET AT TIMES WELL OFFSHORE. NUMEROUS SHOWERS AND
TSTMS WILL BECOME SCATTERED TO ISOLATED THIS WEEKEND...AS THE SFC
LOW PULLS NORTH OF SURF CITY BY DAYBREAK SATURDAY...AND DRY AIR
ALOFT HELPS TO SQUELCH STORM DEVELOPMENT.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 340 PM FRIDAY...QUITE A BIT OF UNCERTAINTY THROUGH THE
EXTENDED AS WIND/WAVE CONDITIONS COULD VARY CONSIDERABLY DEPENDING
ON WHAT HAPPENS WITH TS ISAAC. ANTICIPATE E/SE WINDS MON THROUGH TUE
AS ISAAC MOVES ALONG THE WEST COAST OF FLORIDA AND INTO THE GULF
COAST REGION. THE CONTINUED E/SE WINDS AROUND 10 KTS...UP TO 15 KTS
ACROSS THE SOUTHERN WATERS...WILL GENERATE 2-4 FT SOUTHERLY WIND
WAVES. THESE WIND WAVES WILL COMBINE WITH WHAT SHOULD BE INCREASING
S/SE SWELL OF 4-5FT/9SEC DUE TO TROPICAL SYSTEMS ISAAC AND JOYCE.
GUIDANCE IS NOT VERY ROBUST IN DEVELOPING ANY SIGNIFICANT VERY LONG
PERIOD SWELL...BUT NEVERTHELESS...3-5 FT SEAS ARE EXPECTED THROUGH
TUESDAY...WITH 6 FOOTERS POSSIBLE ACROSS THE SOUTHERN WATERS. SEAS
COULD BUILD MUCH HIGHER WEDNESDAY...ESPECIALLY IF GFS/CMC ARE
CORRECT...DUE TO INCREASING SOUTHERLY WINDS...AND SMALL CRAFT
ADVISORY CONDITIONS WILL BE POSSIBLE AT THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...MRR/RGZ
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
219 PM EDT FRI AUG 24 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE SLOWLY UP THE CAROLINA COAST THROUGH TONIGHT.
HIGH PRESSURE WILL BUILD SOUTHWARD DURING THE WEEKEND...BRINGING
SLIGHTLY DRIER AIR. TROPICAL STORM ISAAC MAY FINALLY REACH HURRICANE
STRENGTH ONCE IT MOVES OUT OF THE CARIBBEAN SEA AND INTO THE GULF OF
MEXICO EARLY NEXT WEEK. REFER TO THE LATEST BULLETINS ISSUED BY THE
NATIONAL HURRICANE CENTER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM FRIDAY...MID TO UPPER LOW WILL TRACK UP THE THE
SOUTHEAST COAST THROUGH TONIGHT. THE H5 CIRCULATION REMAINS BROAD
WITH CENTER TIGHTENING A BIT OVERNIGHT WITH CENTER FORECAST
OVER NC/VA BORDER BY SAT MORNING. THE ASSOCIATED SURFACE LOW JUST
E-SE OF CAPE FEAR THIS AFTERNOON WILL MOVE NORTH AND BECOME MORE
ELONGATED AS IT WEAKENS THROUGH TONIGHT. NAM STILL SHOWING BEST
ENERGY ASSOCIATED WITH THIS LOW TO MOVE FROM COASTAL WATERS JUST
SOUTH OF CAPE FEAR DUE NORTH INTO NC THIS AFTERNOON. HRRR MODEL
SHOWING BEST CHC FOR HEAVIER PCP FROM THE TIP OF CAPE FEAR NORTH
ALONG THE NORTH CAROLINA COAST MAINLY FROM NEW HANOVER COUNTY
THROUGH PENDER COUNTY. THE BEST CHC OF HEAVIER PCP WILL OCCUR
DURING THIS TIME BUT BULLSEYE FOR HEAVIEST RAIN IN TSTMS WILL
REMAIN OVER THE WATERS TO THE EAST. THE GREATEST THREAT THROUGH
WILL BE POTENTIAL FOR FLOODING AS STEERING FLOW OVER MOST LAND
AREAS WILL REMAIN VERY WEAK. PCP WATER VALUES WILL REMAIN AROUND 2
INCHES UP THE CAPE FEAR COAST DROPPING OFF AS YOU MOVE INLAND DOWN
LESS THAN AN INCH IN DRIER AIR AND SUBSIDENCE ON BACK END OF LOW
WEST OF LOCAL CWA...OVER CENTRAL TO WESTERN CAROLINAS. WILL KEEP
LOW END POPS INLAND AS SOME ENERGY ROTATES AROUND THE LOW...BUT
OVERALL CLOUDS AND COOLER NORTHERLY FLOW KEEPING TEMPS JUST AROUND
80 AND OVERALL MORE STABLE ATMOSPHERE.
MODEL SOUNDINGS AND MOISTURE PROFILES SHOWING DRIER AIR WORKING
ITS WAY IN ON THE BACK EDGE OF LOW THROUGH THE MID TO UPPER
LEVELS TONIGHT AS IT LIFTS OFF TO THE NORTH. THIS WILL HELP PCP
SHUT OFF OVER LOCAL AREA. NAM SHOWS PCP WATER VALUES DROPPING
DOWN LESS THAN 1.5 INCHES BY SAT MORNING. CLOUDS...PCP AND FOG
WILL HELP KEEP TEMPS IN THE MID 60S AND CLOSER TO 70 WHERE GREATER
DEWPOINT AIR WILL HANG ON THE LATEST. MAY SEE STRATUS DEVELOP AS
MOISTURE BECOMES TRAPPED UNDER LOW LEVEL INVERSION...MORE PROBABLE
CLOSER TO THE COAST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...MID LEVEL LOW PRESSURE WILL DRIFT SLOWLY TO
THE NORTHEAST AS HIGH PRESSURE BUILDS IN. SATURDAY SHOULD BE DRY AS
THERE IS NOW A CONSIDERABLE SUBSIDENCE INVERSION AROUND 800MB. THE
PRECIPITABLE WATERS DROPPING TO JUST OVER ONE INCH MAY BE A BIT ON
THE DRY SIDE AS THE GFS DOES NOT SEEM TO BE HANDLING THE MASS OF DRY
AIR ACROSS THE MISSISSIPPI VALLEY VERY WELL. THE HIGH RETREATS
NORTHEAST SLIGHTLY SUNDAY AND SLIGHT CHANCE POPS ARE WARRANTED AS
SOUNDINGS BECOME MORE FAVORABLE.
TEMPERATURE FORECAST IS CHALLENGING AS THE 0000 UTC GUIDANCE IS ALL
OVER THE PLACE. FOR EXAMPLE...THERE IS A SIX DEGREE SPREAD WITH
WILMINGTON SATURDAY WITH WARMER MET NUMBERS. THERE IS ALSO A SIX
DEGREE SPREAD IN LUMBERTON FOR SUNDAY WITH THE MAV MUCH WARMER. I
HAVE GENERALLY LEANED TOWARD THE WARMER NUMBERS WHICH HAS BEEN A
WINNING STRATEGY FOR MOST OF THE SUMMER.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 AM FRIDAY...FORECAST CONFIDENCE REMAINS LOW AS SENSIBLE
WEATHER ELEMENTS WILL BE MOSTLY DRIVEN BY THE EVENTUAL TRACK OF
ISAAC. MAINTAINED THE HIGHER TREND OF POPS THROUGH THE PERIOD BUT
SUBSEQUENT SHIFTS MAY WANT TO CONTEMPLATE INTRODUCING A DECREASING
TREND AS ONLY LIMITED FORCING AND MOISTURE WILL BE AVAILABLE IF THE
WESTERN SCENARIO/TRACK VERIFIES. THIS FORCING WILL BE BROAD SPEED
CONVERGENCE WITH THE SOUTHEASTERLY FLOW WHICH GENERALLY DOES NOT YIELD
THAT MUCH FOR OUR AREA...AT LEAST INLAND. THE REMAINDER OF THE
PERIOD WOULD BE MODULATED BY A WEAK FRONT LINGERING IN THE AREA. NO
CHANGES TO TEMPERATURE FORECAST.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...A STATIONARY FRONT IS LOCATED OFFSHORE WITH NE FLOW IN
THE LOW-LEVELS ACROSS THE TERMS. IFR CIGS ARE OCCURRING FROM MYR
S...WITH MVFR CEILINGS ACROSS THE REMAINING TERMS. WIDESPREAD LIGHT
TO OCCASIONALLY MODERATE RAIN IS OCCURRING...AND SO FAR ANY
THUNDERSTORMS HAVE REMAIN OFFSHORE. LOW PRESSURE IS CLEARLY SEEN IN
RADAR LOOPS SE OF CHS MOVING NE.
THINK THUNDERSTORMS WILL REMAIN CLOSEST TO THE ADVANCING LOW
PRESSURE. THIS SHOULD KEEP BEST THUNDERSTORM POTENTIAL OFFSHORE TO
THE SOUTHEAST OF CRE/MYR...WITH THUNDERSTORMS MOST LIKELY AFFECTING
ILM WITH AT LEAST VCTS AFT 19-20Z. THROUGH 22Z TEMPO MVFR CONDITIONS
COULD OCCUR AT FLO/LBT...WITH MVFR/TEMPO IFR AT CRE/MYR. THE ILM
TERMINAL SHOULD HAVE THE BEST POTENTIAL FOR IFR THIS AFTERNOON...BUT
IF THE LOW PASSES TOO FAR OFFSHORE...THEN VCTS/IFR WOULD BE LESS LIKELY.
PRECIPITATION WILL SLOWLY DECREASE AND BY EVENING SHOULD BE
NORTHEAST OF FLO/MYR/CRE AND BY LATE EVENING NORTHEAST OF ALL THE
TERMINALS. SUBSIDENCE IN THE WAKE OF THE PRECIPITATION SHOULD ALLOW
FOR A A GOOD CHANCE OF MVFR VSBYS DEVELOPING AT ALL TERMINALS...AND
IFR CIGS AT THE COASTAL TERMINALS OVERNIGHT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM FRIDAY...SHORTWAVE WILL RIDE UP THE CAPE FEAR COAST
REACHING THE NC/VA BORDER BY MORNING. AT THE SAME TIME AN
ASSOCIATED AREA OF LOW PRESSURE WILL TRACK SLOWLY UP THROUGH THE
LOCAL COASTAL WATERS REACHING TOWARD HATTERAS AFTER MIDNIGHT. THIS
WILL HELP TO PRODUCE MORE WIDESPREAD PRECIPITATION THROUGH THIS
EVENING...WINDING DOWN FROM S TO N TONIGHT... LINGERING LONGEST
OFF THE CAPE FEAR COAST...AND PERHAPS WELL INTO THE NIGHT.
SFC WINDS SPEEDS WILL GENERALLY BE 10 TO 15 KT AND MAY BECOME
GUSTY FOR A TIME LATER TODAY. THE DIRECTION WILL REMAIN N TO NE.
ALTHOUGH SURFACE WINDS REMAIN N-NE...INCREASING LOW LEVEL FLOW
ABOVE THE SURFACE WILL STEER THE STORMS TOWARD THE N-NW THROUGH
THE DAY.
SEAS WILL BUILD TO 3 TO 4 FT ALTHOUGH SEAS MAY REACH 5 FT OR SO...
MAINLY ACROSS THE OUTER WATERS OFF OF CAPE FEAR. MARINERS SHOULD
EXPECT HIGHER WINDS AND SEAS IN THE VICINITY OF PERSISTENT
THUNDERSTORM ACTIVITY. THE VISIBILITY WILL FREQUENTLY BE REDUCED TO
1 NM OR LESS IN RAIN. GIVEN THE COVERAGE OF CONVECTION...SEAS WILL
LIKELY BE ROUGH. AN ELEVATED RISK FOR WATERSPOUTS WILL REMAIN FOR
ONE MORE DAY.
THE BUOYS CONTINUE TO SAMPLE A WEAK ESE SWELL THIS MORNING UP TO
16 SECONDS. THE SWELL WILL BECOME MORE SIGNIFICANT IN THE COMING DAYS.
THE SWELL PERIOD WILL BE ON THE ORDER OF 11 TO 14 SECONDS.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...MOST OF THE FORECAST PERIOD WILL BE
CHARACTERIZED BY LIGHT WIND FIELDS. SHOULD SEE NORTHEAST WINDS TEN
KNOTS OR LESS THROUGH EARLY SUNDAY. WINDS VEER AND INCREASE TO 10-15
LATER SUNDAY CONTINUING INTO EARLY MONDAY. SWAN IS ADVERTISING SEAS
INCREASING FROM AN EARLY RANGE OF 2-4 FEET TO 3-6 FEET LATE VIA A
SIGNIFICANT SWELL COMPONENT.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...EXPECT NORTHEAST WINDS INITIALLY VEERING TO
EAST LATE MONDAY AND FINALLY TO THE SOUTHEAST TUESDAY. SPEEDS WILL
GENERALLY BE TEN KNOTS OR LESS. SOME LINGERING SWELL FROM DISTANT
TROPICAL SYSTEM ISAAC AND JOYCE FOR THAT MATTER WILL KEEP SEAS
HIGHER THAN WINDS FIELDS WOULD NORMALLY SIGNAL WITH 3-6 FEET BOTH
DAYS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...RGZ/MRR
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1234 PM CDT FRI AUG 24 2012
.DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
&&
.AVIATION...
GUSTY WINDS TO 25 KTS WILL BE THE MAIN IMPACT ON TERMINALS THIS
AFTERNOON...AS BAND OF MID LEVEL CLOUDS AND VERY LIGHT SHOWERS
MOVE SLOWLY EAST ACROSS THE REGION. THUNDER POSSIBLE BUT SHOULD
BE ISOLATED.
&&
.PREV DISCUSSION... /ISSUED 627 AM CDT FRI AUG 24 2012/
DISCUSSION...
LOOK FOR VFR CONDITIONS TO DOMINATE WEST CENTRAL TEXAS FOR THE
NEXT 24 HOURS. AVIATION BELOW HAS DETAILS.
AVIATION...
SHOWERS AND THUNDERSTORMS MAY DEVELOP ACROSS WEST CENTRAL TEXAS
TODAY AND TONIGHT. A TROUGH OF LOW PRESSURE ALOFT...WILL CONTINUE
TO MOVE SLOWLY EAST INTO THE CENTRAL TEXAS TODAY AND TONIGHT. THIS
FEATURE MAY PROVIDE THE NECESSARY UPPER DYNAMICS TO INITIATE
SHOWERS AND THUNDERSTORMS. OTHERWISE...PLAN FOR GUSTY SOUTH
SURFACE WINDS ACROSS WEST CENTRAL TEXAS TODAY...ESPECIALLY ACROSS
THE BIG COUNTRY AND CONCHO VALLEY. TONIGHT...SURFACE WINDS WILL
DIMINISH TO AROUND 10 KNOTS OR LESS.
HUBER
PREV DISCUSSION... /ISSUED 328 AM CDT FRI AUG 24 2012/
SHORT TERM...
RAIN CHANCES FOR MOST OF WEST CENTRAL TEXAS LOOK SOMEWHAT PROMISING
FOR THE NEXT 24 HOURS. MODELS INDICATE A SHORT WAVE TROUGH OF LOW
PRESSURE WILL PROVIDE SOME UPPER-LEVEL DYNAMICS. MODELS SHOW THIS
FEATURE BEST AT 700 MB. ALTHOUGH THE NAM AND THE RUC (HIGH
RESOLUTION RAPID REFRESH) INDICATE SOME DECLINE IN CONVECTIVE
COVERAGE BETWEEN NOW AND 18Z...I DECIDED TO INCLUDE THE FIRST 6
HOURS OF THE TODAY PERIOD WITH SLIGHT CHANCE TO CHANCE POPS ACROSS
THE BOARD. IN ADDITION...MODELS CONTINUE AT LEASE A SLIGHT CHANCE
THROUGH TONIGHT. ALSO...HPC QPF GRIDS FOR THE FIRST 24 HOURS LOOK
REASONABLE.
AS FOR TEMPERATURES...NUMBERS CLOSE TO MEX MOS LOOK ON TRACK FOR
TODAY AND TONIGHT. LIMITED SUNSHINE AND NORTHWEST FLOW ALOFT WILL
HOLD AFTERNOON HIGHS TODAY MAINLY IN THE LOWER TO MID 90S. OVERNIGHT
LOWS TONIGHT WILL BE MAINLY IN THE LOWER TO MID 70S.
HUBER
LONG TERM...
BY SATURDAY MORNING THE MID LEVEL TROUGH AXIS WILL STRETCH
NORTHEASTWARD FROM SOUTHERN NEW MEXICO ACROSS THE NORTHERN
PANHANDLE AND INTO THE CENTRAL PLAINS. THE SLOW MOVING UPPER
TROUGH AXIS WILL FINALLY MOVE EAST OF THE FORECAST AREA BY LATE
SUNDAY. UNTIL THEN...ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
POSSIBLE OVER MUCH OF THE FORECAST AREA...FAVORING THE WESTERN AND
NORTHERN CWA.
WITH AN INCREASE IN CLOUD COVER...AFTERNOON HIGHS WILL REMAIN IN
THE LOW TO MID 90S THROUGH THE WEEKEND. MORNING LOWS WILL BE IN
THE LOWER 70S.
UPPER LEVEL HILL PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF
THE DEPARTING UPPER LEVEL TROUGH INTO THE FIRST OF THE COMING
WEEK. THE CENTER OF THE UPPER LEVEL HIGH WILL SETTLE OVER NEW
MEXICO. WITH THE UPPER RIDGE AND SUNNY SKIES DOMINATING THE AREA
AT LEAST THROUGH THE MIDDLE OF NEXT WEEK...AFTERNOON TEMPERATURES
WILL EDGE A LITTLE HIGHER TO THE MID TO UPPER 90S. LOOKING FOR A
DRY FORECAST FOR THE REMAINDER OF THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 95 73 93 71 / 20 20 20 20 20
SAN ANGELO 73 95 74 94 71 / 20 20 20 20 20
JUNCTION 74 92 72 94 72 / 10 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1239 PM CDT FRI AUG 24 2012
.SHORT TERM...THROUGH SUNDAY
239 AM CDT FRI AUG 24 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS MORNING SHOWS AN AREA OF LOW PRESSURE OVER
SOUTHEAST MONTANA. A WEAK WARM FRONT EXTENDS FROM THE LOW ACROSS
CENTRAL MINNESOTA INTO NORTHERN WISCONSIN. REGIONAL RADARS WERE
SHOWING A LINE OF SHOWERS AND THUNDERSTORMS FROM LAKE SUPERIOR
INTO NORTHEAST IOWA.
THE ONGOING CONVECTION WAS BEING FUELED BY A SHORT WAVE TROUGH
MOVING ACROSS MINNESOTA. THE 24.05Z RAP INDICATES THIS WAVE WILL
MOVE EAST INTO WISCONSIN IN THE PRE-DAWN HOURS AND THEN AWAY FROM
THE REGION AFTER SUNRISE. THE ACTIVITY CURRENTLY LOOKS TO BE ON
THE EASTERN EDGE OF THE MU CAPE GRADIENT AS THIS QUICKLY DROPS TO
250 J/KG OR LESS ACROSS WESTERN INTO CENTRAL WISCONSIN. BOTH THE
24.00Z HIRES ARW AND NMM SUGGEST THE ACTIVITY IS THE STRONGEST NOW
AND WILL DISSIPATE THROUGH THE REMAINDER OF THE NIGHT AS IT MOVES
OUT OF THE CAPE AXIS. WILL MONITOR THE LATEST RADAR TRENDS AND
MAKE ADJUSTMENTS AS NEEDED BUT CURRENTLY FEEL THE BEST CHANCE OF
ANY ACTIVITY STILL TO BE ONGOING AFTER 12Z IS ACROSS NORTH CENTRAL
WISCONSIN WHERE THE CAPE IS A LITTLE BETTER AND THE MOISTURE
TRANSPORT SHOULD BE THE STRONGEST. FOR THE AFTERNOON...THE 24.00Z
NAM AND GFS INDICATE ANOTHER WEAK SHORT WAVE TROUGH WILL TRACK
ACROSS NORTHERN MINNESOTA TOWARD LAKE SUPERIOR. THIS WAVE WILL
PRODUCE ONLY SOME WEAK VORTICITY ADVECTION IN THE 500-300 MB LAYER
NORTH OF THE AREA. SOME WEAK ISENTROPIC UP GLIDE WILL CONTINUE
OVER THE REMAINS OF THE WARM FRONT WITH THE NAM SHOWING AROUND 2
UBAR/S ACROSS NORTHWEST INTO CENTRAL WISCONSIN. THIS MAY BE ENOUGH
TO GENERATE SOME ADDITIONAL WIDELY SCATTERED CONVECTION AND WILL
KEEP THE 20 PERCENT CHANCES IN THE I94 CORRIDOR.
AFTER TODAY...THE NEXT CHANCE OF RAIN WILL BE SATURDAY THROUGH
SUNDAY. A LARGE UPPER LEVEL LOW OVER WESTERN CANADA WILL TRACK
EAST WHILE REMAINING NORTH OF THE BORDER. AS IT DOES...A WEAK
UPPER LEVEL LOW OVER THE FOUR CORNERS WILL CONTINUE TO WEAKEN AND
BECOME AN OPEN WAVE WHILE BEING PULLED NORTHEAST AHEAD OF THE
CANADIAN UPPER LEVEL LOW. THE MODELS INDICATE THE REMAINS OF THE
FOUR CORNERS UPPER LEVEL LOW WILL COME THROUGH IN A COUPLE OF
PIECES WITH THE FIRST MOVING ACROSS THE REGION SATURDAY AND THE
SECOND SATURDAY NIGHT AND SUNDAY. NONE OF THE MODELS PRODUCE MUCH
VORTICITY ADVECTION WITH THE NAM AND 23.12Z ECMWF SHOWING 2 PVU/S
OR LESS WHILE THE 24.00Z GFS IS A LITTLE STRONGER SHOWING UP TO 4
PVU/S. A WEAK COLD FRONT OR TROUGH OF LOW PRESSURE SHOULD MOVE
SLOWLY ACROSS THE AREA WITH THE SHORT WAVE TROUGHS. SOME WEAK
FRONTOGENESIS IN THE 1000-700 MB LAYER SHOULD OCCUR WITH THIS
FEATURE SATURDAY AFTERNOON AND THERE SHOULD BE SOME PERSISTENT UP
GLIDE OF 1 TO 3 UBAR/S ON THE 310K SURFACE UNTIL THIS FEATURE
MOVES THROUGH THE AREA. SINCE THE FORCING WITH THESE WAVES IS NOT
THAT STRONG EXPECTING MAINLY SCATTERED CONVECTION TO OCCUR
SATURDAY AS THE LEAD WAVE COMES IN. THE COVERAGE COULD BE A LITTLE
BIT BETTER SATURDAY NIGHT ACROSS THE SOUTH AHEAD OF THE SECOND
WAVE WHERE THE VORTICITY ADVECTION COULD BE A LITTLE BIT STRONGER.
THE SEVERE POTENTIAL LOOKS PRETTY LOW SATURDAY AND SATURDAY NIGHT
WITH ML CAPES OF 500 J/KG OR LESS EXPECTED AND THE 0-6 KM SHEAR IS
ONLY AROUND 25 KNOTS.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
239 AM CDT FRI AUG 24 2012
ONCE THIS SYSTEMS MOVES OUT...A LARGE AREA OF HIGH PRESSURE WILL
BUILD IN OVER THE UPPER MIDWEST AND SHOULD REMAIN THROUGH MUCH OF
THE PERIOD. TOWARD THE END OF THE PERIOD...THE GFS IS TRYING TO
BRING A SHORT WAVE TROUGH AND UPPER LEVEL LOW THROUGH THE TOP OF
THE UPPER LEVEL RIDGE AND ACROSS SOUTHERN CANADA AND THE UPPER
MIDWEST. THE 24.00Z ECMWF MAINTAINS THE UPPER LEVEL RIDGE OVER THE
AREA WITH ANY TROUGHING OVER SOUTHWEST CANADA INTO THE NORTHERN
ROCKIES. WILL TREND TOWARD THE ECMWF SOLUTION AND KEEP THE ENTIRE
PERIOD DRY.
&&
.AVIATION...THROUGH 18Z SATURDAY
1239 PM CDT FRI AUG 24 2012
THE MAIN FOCUS INTO TOMORROW COMES WITH THE CHANCES FOR SHOWERS
AND THUNDERSTORMS LATE THIS AFTERNOON AND TOMORROW MORNING.
A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON BUT WILL LIKELY FORM TO THE NORTH OF THE TAF SITES. A
MID LEVEL CLOUD DECK SHOULD TRACK TO THE NORTH AS WELL WITH SKIES
CLEARING OUT TO THE SOUTH. WINDS WILL LIGHTEN UP OVERNIGHT AS WELL
BEFORE MORE MID LEVEL CLOUDS MOVE BACK IN BEFORE DAY BREAK. THE
NEXT STORM SYSTEM THEN MOVES IN FROM THE WEST TOMORROW MORNING
WITH SHOWERS AND THUNDERSTORMS GETTING NEAR RST BY LATE MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
239 AM CDT FRI AUG 24 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH