Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/28/12
AREA FORECAST DISCUSSION
NWS PUEBLO CO
245 PM MDT SUN AUG 26 2012
.SHORT TERM...
(TONIGHT AND MONDAY)
AN UPR RIDGE WL REMAIN CENTERED OVR SRN CO AND NRN NM THROUGH MON.
SHOWERS AND THUNDERSTORMS WILL CONTINUE OVR THE HIGHER TERRAIN THRU
THE EVENING HOURS...BUT ARE EXPECTED TO DIE OFF BY MIDNIGHT. THE NAM
RAP13 AND HRRR SHOW OF A LINE OF CONVECTION DEVELOPING OVR THE
EASTERN CO PLAINS LATER THIS AFTERNOON WHICH MOVES EASTWARD INTO
EARLY EVENING. SATELLITE AND RADAR ARE SHOWING A LINE OF SOME
CONVECTION ALONG A WEAK BOUNDARY THAT EXTENDS FROM NE CO AND
SOUTHWESTWARD WHICH HAS PRODUCED SOME THUNDERSTORMS IN NERN EL PASO
COUNTY. THE MODELS HAVE THE RIGHT IDEA...BUT NOT SURE HOW FAR
SOUTHWARD THE CONVECTION WL DEVELOP. WL GO WITH SOME ISOLD POPS OVR
AT LEAST NORTHERN PORTION OF THE SOUTHEAST PLAINS EARLY THIS EVENING.
ON MONDAY THERE WILL STILL BE SOME RESIDUAL MOISTURE UNDER THE RIDGE
OVR THE AREA...AND ISOLD TO SCT SHOWERS AND TSTMS ARE AGAIN EXPECTED
TO DEVELOP OVR THE HYR TRRN. THE SERN PLAINS SHOULD BE DRY ON
MONDAY. IN GENERAL...HIGH TEMPS SHOULD BE ABOUT 5-10 DEGREE ABOVE
AVERAGE. /28
.LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
...HOT AND DRY WEATHER TO CONTINUE THROUGH NEXT WEEK...
NO CHANGES SEEN FOR THE EXTENDED FORECAST. ALL GUIDANCE POINTS TO
A CONTINUATION OF CURRENT CONDITIONS. HIGH PRESSURE CENTERED OVR
S CO WILL BE THE MAIN PLAYER...AND THIS WILL LEAVE THE ERN CO PLAINS
IN A VERY WARM AND GENERALLY DRY PATTERN THRU AT LEAST THE MIDDLE OF
THE WEEK. TEMPS SHOULD TOP OUT IN THE MID 90S...POSSIBLY HIGHER...FOR
A GOOD PORTION OF THE PLAINS BOTH TUE AND WED. POPS LOOK PRETTY LOW
OVER THE PLAINS...AND ONLY SCT STORMS ARE EXPECTED OVR THE MTS FOR
THIS PERIOD.
MAIN QUESTION IS HOW QUICKLY THE UPPER RIDGE BREAKS DOWN. THE ECMWF
MAINTAINS A STRONG UPPER HIGH...AND KEEPS MOST OF THE ACTIVE WX TO
OUR N THRU THE END OF THE WEEK AND EVEN INTO NEXT WEEKEND. THE GFS IS
STILL MORE OPTIMISTIC AND BRINGS AT LEAST A LOW CHANCE OF PRECIP E
OF THE MTS AS A SERIES OF WEAK FRONTAL PUSHES MOVE ACROSS THE AREA
THU AND SAT NEXT WEEK. WILL STICK CLOSER TO PERSISTENCE FOR NOW AND
STAY CLOSE TO THE ENSEMBLE CONSENSUS...WHICH IS CLOSE TO THE OP
ECMWF FORECAST OF DRY AND VERY WARM CONDITIONS. ROSE
&&
.AVIATION...
SOME SHOWERS AND THUNDERSTORMS WILL CONTINUE OVR THE HYR TRRN INTO
THE EVENING BUT IS EXPECTED TO END BEFORE MIDNIGHT. KALS COULD SEE
SOME TSTMS IN THE VCNTY THRU ABOUT 02Z. AT KCOS AND KPUB...CHANCES
FOR TSTM LOOK QUITE LOW. VFR CONDITIONS ARE EXPECTED AT THE TAF
SITE FOR THE NEXT 24 HRS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
28/44
AREA FORECAST DISCUSSION
NWS DENVER CO
248 PM MDT SUN AUG 26 2012
.SHORT TERM...STORMS DEVELOPING ALONG A WIND CONVERGENCE BOUNDARY
SNAKING ACROSS SERN ELBERT...EXTREME NWRN LINCOLN AND SERN
WASHINGTON COUNTIES AS OF 20Z WILL BE THE AREA TO WATCH FOR THE
NEXT FEW HOURS. DEWPOINTS IN THE MID-UPPER 50S EAST OF THIS
BOUNDARY AND IN THE 30S WEST OF THERE. GOOD SOUTHERLY INFLOW
GENERATING A FEW WEAK VORTICITY COUPLETS INDICATED ON RADAR ALONG
THIS CONVERGENCE LINE. LATEST RUC IS INDICATING SFC BASED CAPES IN
THE 1000-1400 J/KG RANGE IN THE MOIST AIR. HOWEVER STRONG MID-
LEVEL STABLE LAYER MAY HINDER THE GROWTH OF STRONG STORMS. FOR
NOW WILL UP POPS ALONG THIS CONVERGENCE BOUNDARY AND EXTEND 20-30
PCT POPS NORTHWARD ACROSS PHILLIPS AND SEDGWICK COUNTIES THRU EARLY
THIS EVENING. MODELS SHOW THIS BOUNDARY AND THE MOIST AIR SHIFTING
EAST OUT OF THE STATE BETWEEN 03-06Z THIS EVENING. ELSEWHERE...
CONVECTION HAS STRUGGLED TO GET GOING IN THE HIGH COUNTRY...NO
DOUBT BECAUSE OF THE STRONG WARMING AND STABILITY AT MID-LEVELS.
SHOULD ANY STORMS MANAGE TO DEVELOP...WOULDN/T EXPECT THEM TO LAST
LONG. LOOKING FOR LOW TEMPERATURES TONIGHT TO BE A FEW DEGREES
WARMER THAN THOSE LAST NIGHT.
ON MONDAY...A 594 DECAMETER UPPER RIDGE POSITIONS SQUARELY OVER
COLORADO. MID-LEVEL MOISTURE OF SUBTROPICAL ORIGIN WILL CONTINUE
TO RIDE NORTH UP THE WEST SIDE OF THE RIDGE AND OVER WESTERN
COLORADO DURING THE DAY. BELIEVE WE/LL SEE A BIT MORE STORM
ACTIVITY IN THE HIGH COUNTRY TOMORROW. EAST OF THE MTNS...STORMS
WILL STRUGGLE TO DEVELOP...ALTHOUGH COULD SEE A FEW HIGH BASED
STORMS DRIFTING OFF THE FRONT RANGE AND OVER THE NEARBY PLAINS
LATE IN THE DAY. FOR NOW WILL KEEP POPS ON THE VERY LOW SIDE IN
THE I-25 URBAN CORRIDOR BUT WILL GO WITH 20-30 PCT POPS IN THE
HIGH COUNTRY. FARTHER OUT ON THE PLAINS WILL KEEP THINGS DRY.
LOOKING FOR ANOTHER DAY OF 90 DEG TEMPERATURES AT LOWER
ELEVATIONS.
.LONG TERM...THE RIDGE OF HIGH PRESSURE WILL REMAIN ANCHORED OVER
COLORADO THROUGH WEDNESDAY. HOTTER TEMPERATURES AND LIMITED
MOISTURE WILL OCCUR THROUGH FIRST HALF OF THE WEEK. THE BEST CHC
OF THUNDERSTORMS WILL BE OVER THE MOUNTAINS EACH AFTERNOON AND
EVENING. THE WINDS ALOFT WILL REMAIN LIGHT. LATE WEDNESDAY INTO
THURSDAY THE RIDGE WILL FLATTEN AND THE FLOW ALOFT BECOME
SOUTHWESTERLY AS AN UPPER TROUGH MOVES ACROSS THE NRN ROCKIES. BY
THURSDAY THE RIDGE WILL HAVE SHIFTED INTO THE CENTRAL
PLAINS/MIDWEST REGION. THERE WILL BE A MODEST INCREASE IN
SUBTROPICAL MOISTURE AS WELL...WITH A LITTLE BETTER CHANCE OF
PRECIPITATION IN THE MOUNTAINS AND A SLIGHT CHANCE SPREADING INTO
THE NORTHEAST PLAINS FRIDAY THROUGH SUNDAY. IT WILL NOT BE AS HOT
AS A COUPLE OF WEAK FRONTAL BOUNDARIES SLIP INTO THE CWFA FROM
THE NORTH...ONE LATE WEDNESDAY/THURSDAY AND ANOTHER SATURDAY.
&&
.AVIATION...VFR CONDITIONS TO CONTINUE THROUGH MONDAY UNDER A
RIDGE OF HIGH PRESSURE. COULD SEE A FEW HIGH BASED MOSTLY DRY AND
GUSTY STOMS MOVING OFF THE FOOTHILLS LATE MONDAY AFTERNOON.
OTHERWISE LIGHT EAST-SOUTHEASTERLY WINDS WILL BECOME SOUTHERLY OR
DRAINAGE OVERNIGHT. A SIMILAR WIND PATTERN IS EXPECTED ON MONDAY.
&&
.HYDROLOGY...NO HEAVY RAIN OR FLASH FLOOD ISSUES ANTICIPATED
DURING THE NEXT 24 HOURS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....COOPER
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1250 PM CDT SUN AUG 26 2012
.DISCUSSION...
ISSUED 910 AM CDT SUN AUG 26 2012
SHORT-WAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY OVER EASTERN
KANSAS/OKLAHOMA WILL BE THE PRIMARY FOCUSING MECHANISM FOR SHOWERS
AND THUNDERSTORMS TODAY INTO TONIGHT. LEAD WAVE HAS TRIGGERED
SCATTERED SHOWERS ACROSS THE AREA THIS MORNING...HOWEVER THESE
ARE RAPIDLY LIFTING NORTHWARD AND SHOULD CLEAR MUCH OF THE KILX
CWA WITHIN THE NEXT COUPLE OF HOURS. AFTER A BRIEF LULL IN THE
PRECIP...HIGH-RES MODELS SUCH AS THE HRRR DEVELOP ADDITIONAL
CONVECTION ACROSS WEST-CENTRAL ILLINOIS INTO MISSOURI BY MID TO
LATE AFTERNOON. WITH FORECAST SOUNDINGS INDICATING CAPE VALUES OF
1000 TO 1500J/KG...A FEW STRONG STORMS COULD DEVELOP. MAIN THREATS
FROM ANY STORMS LATER TODAY WILL BE GUSTY WINDS AND HEAVY
DOWNPOURS. HAVE ADJUSTED THE FORECAST TO BETTER ACCOUNT FOR
CURRENT TRENDS. HAVE REMOVED THUNDER MENTION DURING THE
MORNING...AND FOCUSED BEST CHANCES FOR CONVECTION THIS AFTERNOON
ALONG/WEST OF I-55. SHOWERS/STORMS WILL THEN SPREAD FURTHER
EASTWARD INTO EAST-CENTRAL ILLINOIS TONIGHT...AS THE UPPER WAVE
AND ASSOCIATED COLD FRONT MOVE ACROSS THE AREA.
&&
.AVIATION...
ISSUED 1250 PM CDT SUN AUG 26 2012
CEILINGS WILL REMAIN IN THE VFR CATEGORY AT THE I-72 TERMINALS
THIS AFTERNOON...WHILE MVFR/IFR CEILINGS PERSIST AT BOTH KPIA AND
KBMI. ONGOING SHOWERS ALONG/WEST OF THE ILLINOIS RIVER WILL CONTINUE
TO IMPACT KPIA INTO EARLY EVENING...WHILE CONVECTIVE DEVELOPMENT
FURTHER EAST STILL REMAINS IN QUESTION. WITH PARTIAL SUNSHINE
ALLOWING FOR MODEST DESTABILIZATION EAST OF THE ILLINOIS
RIVER...IT APPEARS SCATTERED SHOWERS/STORMS WILL DEVELOP THIS
AFTERNOON AND EVENING. DUE TO UNCERTAINTY CONCERNING EXACT AREAL
COVERAGE AND TIMING...HAVE ONLY INCLUDED VCTS AT THE REMAINING
TERMINALS. ANY CONVECTION THAT DEVELOPS WILL TEND TO PUSH EAST AND
SOUTH OF THE TAF SITES LATER THIS EVENING AS A COLD FRONT DROPS
INTO THE REGION. WINDS WILL BECOME LIGHT/VARIABLE IN THE VICINITY
OF THE FRONT...POTENTIALLY LEADING TO IFR CEILINGS AND AREAS OF
FOG AT KPIA AND KBMI AFTER 08Z. FURTHER SOUTH...WILL KEEP CEILINGS
IN THE MVFR CATEGORY THROUGH THE NIGHT. SKIES WILL CLEAR FROM
NORTH TO SOUTH ACROSS THE AREA BY MONDAY MORNING...AS WINDS SWITCH
TO THE NORTH BEHIND THE DEPARTING FRONT.
BARNES
&&
.PREV DISCUSSION...
ISSUED 302 AM CDT SUN AUG 26 2012
07Z SURFACE ANALYSIS INDICATED A 1011 MB LOW NEAR TOPEKA WITH A WARM
FRONT ARCING NORTHEAST NEAR THE IA/MO BORDER. LOW 70S DEWPOINTS
HAD ADVECTED NORTH TO THIS BOUNDARY. AT THE MID LEVELS...00Z U/A
ANALYSIS AND WATER VAPOR IMAGERY SHOWED A SLOW MOVING SHORTWAVE TROUGH
AXIS OVER EASTERN KS. REGIONAL RADAR MOSAICS INDICATED WIDESPREAD
RAIN AND EMBEDDED THUNDER SHIFTING NORTHEAST FROM WESTERN MO INTO
SOUTHERN IA...ASSOCIATED WITH THESE SFC AND UPPER FEATURES.
LOCALLY...BROAD ELEVATED WARM MOIST ADVECTION WAS PRODUCING PLENTY
OF AC BUT NOT MUCH IN THE WAY OF SHOWERS YET. MAIN FORECAST ISSUE IS
RAINFALL TIMING/COVERAGE/AMOUNTS TODAY INTO MONDAY AS THE SYSTEM
SHIFTS ACROSS THE CWA.
SHORT TERM...TODAY THROUGH MONDAY
MOISTURE ADVECTION AHEAD OF THE MID LEVEL TROUGH WILL BRING A
VERY MOIST AIR MASS INTO THE CWA TODAY AND TONIGHT. W/V IMAGERY
SHOWS A MID-LEVEL TROPICAL/PACIFIC MOISTURE PLUME WELL
ENTRAINED INTO THIS SYSTEM...WHILE LLVL FLOW HAS BROUGHT GULF MOISTURE
AND ASSOCIATED 70+ DEWPOINTS NORTH INTO THE MIDWEST. WITH THESE
FACTORS IN PLACE IT IS NOT SURPRISING TO SEE 2.0-2.2 INCH
PRECIPITABLE WATER VALUES ON FORECAST SOUNDINGS AND NUMERICAL
MODEL OUTPUT. SUCH NUMBERS ARE NEAR THE 99TH PERCENTILE FOR LATE
AUGUST...OR 175 PERCENT OF NORMAL. WITH BROAD ISENTROPIC LIFT IN
PLACE...WAVES OF ADDITIONAL FORCING ASSOCIATED WITH 850-500 MB
TROUGHS AND SHORTWAVE ENERGY WILL BRING SEVERAL ROUNDS OF SHOWERS
AND EMBEDDED THUNDERSTORMS TO THE CWA TODAY AND TONIGHT. HIGHEST
QPF VALUES REMAIN FOCUSED ON THE WESTERN HALF OF THE CWA WHERE
LIFT IS MAXIMIZED THIS AFTERNOON AND EVENING. WIDESPREAD HALF TO
ONE INCH AMOUNTS FROM EAST TO WEST NOW LOOK LIKELY BY MONDAY
MORNING. SOME SIGNS THAT TRAINING OF CONVECTION COULD PRODUCE
ISOLATED 2 INCH AMOUNTS ESPECIALLY NEAR THE NW CWA. PRIMARY
SHORTWAVE WEAKENS AS IT CROSSES THE MISSISSIPPI RIVER THIS
EVENING...LEADING TO LIGHTER TOTALS AND LESS COVERAGE SHOWERS
OVERNIGHT. 00Z MODELS HAVE CONTINUED THE TREND FROM 12Z OF SLOWING
SYSTEM EXIT TO THE EAST AND WILL KEEP CHANCE POPS FOR THE
SOUTHEAST HALF INTO MONDAY AFTERNOON...THOUGH MOST ORGANIZED RAINS
SHOULD BE DISSIPATING BY THEN. DRIER AIR FILTERING IN ON NORTH
WINDS BRING CLEARING SKIES FROM THE NORTH MONDAY AFTERNOON.
AS FAR AS TEMPERATURES ARE CONCERNED...THICK CLOUD COVER AND
OCCASIONAL RAIN MAY KEEP THE NW CWA IN THE UPPER 70S TODAY...WHILE
THE FAR SE COULD SEE ENOUGH SUN AND DRY HOURS TO GET INTO THE UPPER
80S. MONDAY...SUNNIER LOCATIONS IN THE NORTHWEST SHOULD REBOUND
WELL INTO THE UPPER 80S AS COLD ADVECTION IS NON-EXISTENT BEHIND
THE FRONT. CLOUDS LINGERING THROUGH MUCH OF THE AFTERNOON COULD
KEEP PARTS OF THE E/SE IN THE LOWER 80S.
LONG TERM...TUESDAY THROUGH SATURDAY
AN IDEAL STRETCH OF LATE SUMMER WEATHER LOOKS TO SET UP ACROSS THE
AREA FOR MUCH OF THE WEEK...AS SURFACE AND UPPER RIDGING BUILD
OVER THE MIDWEST. THIS WILL PRODUCE MOSTLY CLEAR SKIES...LIGHT
WINDS...AND SEASONABLY LOW HUMIDITY. THIS DRY AIR WILL ALLOW FOR
LARGE DIURNAL TEMPERATURE SWINGS WITH LOWS MAINLY IN THE LOW/MID
60S AND HIGHS IN THE MID 80S TO LOWER 90S. ANY HOPES FOR RAIN WILL
HINGE ON THE EVENTUAL PATH OF ISAAC REMNANTS FOR THE
FRIDAY/SATURDAY TIME FRAME. TO SAY MODEL AGREEMENT IS POOR WOULD BE
AN UNDERSTATEMENT...AND WILL CONTINUE TO KEEP POPS BELOW
MENTIONABLE LEVELS.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
910 AM CDT SUN AUG 26 2012
.DISCUSSION...
ISSUED 910 AM CDT SUN AUG 26 2012
SHORT-WAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY OVER EASTERN
KANSAS/OKLAHOMA WILL BE THE PRIMARY FOCUSING MECHANISM FOR SHOWERS
AND THUNDERSTORMS TODAY INTO TONIGHT. LEAD WAVE HAS TRIGGERED
SCATTERED SHOWERS ACROSS THE AREA THIS MORNING...HOWEVER THESE
ARE RAPIDLY LIFTING NORTHWARD AND SHOULD CLEAR MUCH OF THE KILX
CWA WITHIN THE NEXT COUPLE OF HOURS. AFTER A BRIEF LULL IN THE
PRECIP...HIGH-RES MODELS SUCH AS THE HRRR DEVELOP ADDITIONAL
CONVECTION ACROSS WEST-CENTRAL ILLINOIS INTO MISSOURI BY MID TO
LATE AFTERNOON. WITH FORECAST SOUNDINGS INDICATING CAPE VALUES OF
1000 TO 1500J/KG...A FEW STRONG STORMS COULD DEVELOP. MAIN THREATS
FROM ANY STORMS LATER TODAY WILL BE GUSTY WINDS AND HEAVY
DOWNPOURS. HAVE ADJUSTED THE FORECAST TO BETTER ACCOUNT FOR
CURRENT TRENDS. HAVE REMOVED THUNDER MENTION DURING THE
MORNING...AND FOCUSED BEST CHANCES FOR CONVECTION THIS AFTERNOON
ALONG/WEST OF I-55. SHOWERS/STORMS WILL THEN SPREAD FURTHER
EASTWARD INTO EAST-CENTRAL ILLINOIS TONIGHT...AS THE UPPER WAVE
AND ASSOCIATED COLD FRONT MOVE ACROSS THE AREA.
BARNES
&&
.AVIATION...
ISSUED 642 AM CDT SUN AUG 26 2012
MVFR CEILINGS STARTING TO SPREAD IN FROM THE WEST...WITH MAINLY
KPIA AFFECTED AT THE MOMENT. SHOULD SLOWLY SEE THESE OVERSPREAD
THE REMAINDER OF THE TAF SITES AS THE MORNING PROGRESSES. LATEST
MODEL GUIDANCE SHOWING SOME POTENTIAL FOR THESE TO RISE AGAIN THIS
AFTERNOON. SHOWERS HAVE BEGUN TO INCREASE IN COVERAGE AS OF
LATE... ALTHOUGH MAIN PRECIPITATION SHIELD STILL FURTHER WEST FROM
SOUTHWEST MISSOURI INTO EAST CENTRAL IOWA. THIS WILL MOVE INTO THE
AREA LATER THIS MORNING. HAVE NOT SEEN MUCH IN THE WAY OF
LIGHTNING ACTIVITY SO FAR...BUT GUIDANCE SUGGESTING THE POTENTIAL
SHOULD INCREASE LATE MORNING INTO AFTERNOON...SO HAVE INTRODUCED
VCTS AT ALL SITES.
MAIN COLD FRONT EXPECTED TO CROSS THE TAF SITES IN THE 09-12Z TIME
FRAME. GIVEN THE RAIN THAT WILL BE OCCURRING LATER TODAY...HAVE
SOME CONCERNS THAT LOW CLOUDS AND FOG COULD DEVELOP BY THE TIME
OF FRONTAL PASSAGE. SREF GUIDANCE INDICATES AREAS FROM KBMI/KPIA
NORTHWEST ARE MOST SUSCEPTIBLE...AND HAVE INTRODUCED SOME IFR
CEILINGS LATE IN THE FORECAST PERIOD AT THESE SITES.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 302 AM CDT SUN AUG 26 2012
07Z SURFACE ANALYSIS INDICATED A 1011 MB LOW NEAR TOPEKA WITH A WARM
FRONT ARCING NORTHEAST NEAR THE IA/MO BORDER. LOW 70S DEWPOINTS
HAD ADVECTED NORTH TO THIS BOUNDARY. AT THE MID LEVELS...00Z U/A
ANALYSIS AND WATER VAPOR IMAGERY SHOWED A SLOW MOVING SHORTWAVE TROUGH
AXIS OVER EASTERN KS. REGIONAL RADAR MOSAICS INDICATED WIDESPREAD
RAIN AND EMBEDDED THUNDER SHIFTING NORTHEAST FROM WESTERN MO INTO
SOUTHERN IA...ASSOCIATED WITH THESE SFC AND UPPER FEATURES.
LOCALLY...BROAD ELEVATED WARM MOIST ADVECTION WAS PRODUCING PLENTY
OF AC BUT NOT MUCH IN THE WAY OF SHOWERS YET. MAIN FORECAST ISSUE IS
RAINFALL TIMING/COVERAGE/AMOUNTS TODAY INTO MONDAY AS THE SYSTEM
SHIFTS ACROSS THE CWA.
SHORT TERM...TODAY THROUGH MONDAY
MOISTURE ADVECTION AHEAD OF THE MID LEVEL TROUGH WILL BRING A
VERY MOIST AIR MASS INTO THE CWA TODAY AND TONIGHT. W/V IMAGERY
SHOWS A MID-LEVEL TROPICAL/PACIFIC MOISTURE PLUME WELL
ENTRAINED INTO THIS SYSTEM...WHILE LLVL FLOW HAS BROUGHT GULF MOISTURE
AND ASSOCIATED 70+ DEWPOINTS NORTH INTO THE MIDWEST. WITH THESE
FACTORS IN PLACE IT IS NOT SURPRISING TO SEE 2.0-2.2 INCH
PRECIPITABLE WATER VALUES ON FORECAST SOUNDINGS AND NUMERICAL
MODEL OUTPUT. SUCH NUMBERS ARE NEAR THE 99TH PERCENTILE FOR LATE
AUGUST...OR 175 PERCENT OF NORMAL. WITH BROAD ISENTROPIC LIFT IN
PLACE...WAVES OF ADDITIONAL FORCING ASSOCIATED WITH 850-500 MB
TROUGHS AND SHORTWAVE ENERGY WILL BRING SEVERAL ROUNDS OF SHOWERS
AND EMBEDDED THUNDERSTORMS TO THE CWA TODAY AND TONIGHT. HIGHEST
QPF VALUES REMAIN FOCUSED ON THE WESTERN HALF OF THE CWA WHERE
LIFT IS MAXIMIZED THIS AFTERNOON AND EVENING. WIDESPREAD HALF TO
ONE INCH AMOUNTS FROM EAST TO WEST NOW LOOK LIKELY BY MONDAY
MORNING. SOME SIGNS THAT TRAINING OF CONVECTION COULD PRODUCE
ISOLATED 2 INCH AMOUNTS ESPECIALLY NEAR THE NW CWA. PRIMARY
SHORTWAVE WEAKENS AS IT CROSSES THE MISSISSIPPI RIVER THIS
EVENING...LEADING TO LIGHTER TOTALS AND LESS COVERAGE SHOWERS
OVERNIGHT. 00Z MODELS HAVE CONTINUED THE TREND FROM 12Z OF SLOWING
SYSTEM EXIT TO THE EAST AND WILL KEEP CHANCE POPS FOR THE
SOUTHEAST HALF INTO MONDAY AFTERNOON...THOUGH MOST ORGANIZED RAINS
SHOULD BE DISSIPATING BY THEN. DRIER AIR FILTERING IN ON NORTH
WINDS BRING CLEARING SKIES FROM THE NORTH MONDAY AFTERNOON.
AS FAR AS TEMPERATURES ARE CONCERNED...THICK CLOUD COVER AND
OCCASIONAL RAIN MAY KEEP THE NW CWA IN THE UPPER 70S TODAY...WHILE
THE FAR SE COULD SEE ENOUGH SUN AND DRY HOURS TO GET INTO THE UPPER
80S. MONDAY...SUNNIER LOCATIONS IN THE NORTHWEST SHOULD REBOUND
WELL INTO THE UPPER 80S AS COLD ADVECTION IS NON-EXISTENT BEHIND
THE FRONT. CLOUDS LINGERING THROUGH MUCH OF THE AFTERNOON COULD
KEEP PARTS OF THE E/SE IN THE LOWER 80S.
LONG TERM...TUESDAY THROUGH SATURDAY
AN IDEAL STRETCH OF LATE SUMMER WEATHER LOOKS TO SET UP ACROSS THE
AREA FOR MUCH OF THE WEEK...AS SURFACE AND UPPER RIDGING BUILD
OVER THE MIDWEST. THIS WILL PRODUCE MOSTLY CLEAR SKIES...LIGHT
WINDS...AND SEASONABLY LOW HUMIDITY. THIS DRY AIR WILL ALLOW FOR
LARGE DIURNAL TEMPERATURE SWINGS WITH LOWS MAINLY IN THE LOW/MID
60S AND HIGHS IN THE MID 80S TO LOWER 90S. ANY HOPES FOR RAIN WILL
HINGE ON THE EVENTUAL PATH OF ISAAC REMNANTS FOR THE
FRIDAY/SATURDAY TIME FRAME. TO SAY MODEL AGREEMENT IS POOR WOULD BE
AN UNDERSTATEMENT...AND WILL CONTINUE TO KEEP POPS BELOW
MENTIONABLE LEVELS.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
111 PM EDT SUN AUG 26 2012
.AVIATION...18Z TAFS
BAND OF INITIALLY HIGH BASED SHOWERS ACROSS NE IL...ASSOCIATED
WITH AN AREA OF STRONG MID LVL MOISTURE ADVECTION...SHOULD CLIP
SBN WITH SHOWERS POSSIBLE AT THE TERMINAL BY 19/20Z. MUCH LOWER
CHANCE FOR MORE ISOLATED SHOWER/STORM ACTIVITY AT FWA ALONG THE
LEADING EDGE OF DEEPER MOISTURE AFTER 20/21Z...SO OPTED FOR A
VCTS MENTION HERE. FLIGHT CONDITIONS WILL DETERIORATE TONIGHT INTO
MONDAY MORNING...ESPECIALLY AT SBN...AS DEEPER TROPICAL MOISTURE
OVERSPREADS THE AREA AHEAD OF A SHEARING UPPER LEVEL WAVE AND WEAK
SFC REFLECTION. THE BULK OF THE SHOWER ACTIVITY...AND POSSIBLY
SOME ISO THUNDER...SHOULD ARRIVE THIS EVENING INTO THE EARLY
OVERNIGHT HOURS AT SBN AND LATER TONIGHT AT FWA.
&&
.PREV DISCUSSION... /ISSUED 439 AM EDT SUN AUG 26 2012/
SHORT TERM...TODAY THROUGH MONDAY NIGHT.
TROUGHINESS FROM CLOSED UPPER LOW MOVING TOWARDS HUDSON BAY THIS
MORNING WILL ATTEMPT TO GRAB HOLD OF WEAK BUT MOISTURE LADEN WAVE
CURRENTLY IN SE KANSAS AND PULL IT NE TODAY INTO TONIGHT. LIGHTER
SHOWER ACTIVITY NOTED ACROSS PORTIONS OF WISCONSIN WITH MORE
WIDESPREAD/HEAVIER SHOWERS/STORMS FROM S CNTRL IOWA INTO SW MISSOURI
AND SE KANSAS. NEAR/SHORT TERM MODELS HAVE VARIETY OF SOLUTIONS IN
HANDLING OF THIS ENERGY AND EFFECTS ON THE AREA. PAST SEVERAL RUNS
OF HRRR HAVE SHOWN DEVELOPMENT SHOULD BE UNDERWAY ACROSS WESTERN
ILLINOIS IN AREA LL CONVERGENCE...30 KT LLJ AND PWATS AROUND 2
INCHES. HOWEVER...LITTLE PRECIP NOTED AND NO INDICATIONS OF ANYTHING
IMMINENT. AT THIS POINT...DISCOUNTING (BUT NOT DISCARDING) THIS IDEA
WHICH WOULD BRING IN SHOWERS TO WESTERN AREAS LATER THIS MORNING.
REMAINING MODELS LEAN TOWARDS AWAITING ARRIVAL OF WAVE INTO ILLINOIS
LATER TODAY INTO TONIGHT ALONG A COLD FRONT SET TO MOVE THROUGH
TONIGHT INTO MONDAY. GIVEN BEST DYNAMICS MOVING NORTH OF THE
AREA...WAVE WILL SLOWLY SHEAR OUT AS IT MOVES NORTHEAST.
HOWEVER...GIVEN DEEP MSTR IN PLACE (OVER 2 INCHES FROM OKLAHOMA INTO
SW MISSOURI)...EXPECT CURRENT ACTIVITY TO REMAIN INTACT/EXPAND AS IT
MOVES NORTHEAST. MAJORITY OF MODELS EVENTUALLY FOCUS LLJ INTO
NORTHERN ILLINOIS IN AXIS OF HIGHER PWATS...CAUSING ADDITIONAL
CONVECTION TO BREAK OUT. FROM THIS POINT IS WHERE MODELS DIVERGE
WITH ANYTHING FROM GLANCING BLOW OF SHOWERS IN NW AREAS...TO
WIDESPREAD SHOWERS/EMBEDDED STORMS...TO CONVECTION REMAINING MAINLY
SOUTH OF THE AREA (SOME HINTS OF THIS IN WATER VAPOR WITH GREATEST
MSTR SHIFTING MORE EAST THAN NORTH). DO THINK THAT MOST...IF NOT ALL
AREAS WILL SEE AT LEAST SOME MEASURABLE RAINFALL WITH BASIN AVERAGES
IN THE QUARTER TO HALF INCH RANGE. WITH POTENTIAL FOR MORE CELLULAR
SETUP VS WIDESPREAD AREA OF RAIN/STORMS HAVE OPTED TO CONTINUE WITH
ARRIVAL OF HIGH END CHC POPS NW AREAS LATER THIS
AFTERNOON...EXPANDING TO HIGHER END LIKELY ACROSS MUCH OF THE AREA
BY LATER TONIGHT.
HAVE NUDGED UP POPS SOMEWHAT MONDAY MORNING IN EASTERN AREAS WITH
CONCERNS ABOUT SLOWER DEPARTURE OF ENERGY. IF 3Z SREF WERE TO
VERIFY...SHOWERS/STORMS WOULD REMAIN ACROSS MUCH OF THE AREA THROUGH
MOST OF MONDAY. THIS MODEL IS PRESENTLY AN OUTLIER SO WHILE AT LEAST
CONSIDERED...DISCOUNTED FOR THE TIME BEING WITH DRYING CONDITIONS
FROM NW TO SE THROUGH THE DAY.
TEMPERATURES HAVE SERIOUS BUST POTENTIAL TODAY ACROSS THE AREA. IR
SAT DATA SHOWS CLOUD COVER TO BEGIN TO ARRIVE IN NW AREAS THIS
MORNING AND THEN INCREASING IN COVERAGE/THICKNESS INTO THIS
AFTERNOON. COOLEST HIGHS ARE EXPECTED IN THESE LOCATIONS AS A RESULT
OF THE LIMITED HEATING WITH WARMER TEMPS...CLOSE TO 90 EXPECTED
ACROSS PORTIONS OF NE INDIANA INTO NW OHIO. IF PRECIP DOES INDEED
WAIT UNTIL CLOSER TO THIS EVENING AND HIGH CLOUDS REMAIN THIN
ENOUGH...HIGHS IN THE NW WILL BE TOO COOL AND NEED ADJUSTING. FOR
NOW WILL GENERALLY LEAVE UNTOUCHED. MUGGY NIGHT IN STORE WITH DEWPTS
IN THE UPPER 60S TO AROUND 70 AND LOWS NEAR OR INTO THE 70S MUCH OF
THE NIGHT. ON MONDAY...TEMPS WILL REMAIN AN ISSUE WITH CLEARING
EXPECTED NW WHERE A NICE REBOUND COULD OCCUR GIVEN OVERNIGHT LOWS
ONLY AROUND 70...WITH SE AREAS SLOWER TO CLIMB WITH LINGERING CLOUD
COVER. HAVE KEPT MON/MON NGT LOWS AS IS.
LONG TERM...
TUESDAY THROUGH SATURDAY. FEW CHNGS WRT LONG TERM. CRNT CNTL PLAINS
SHORTWAVE TO MINOR NEWD AS ASSERTIVE MANITOBA MID TROPOSPHERIC
VORTEX SWEEPS INTO JAMES BAY BY ERLY MONDAY. SFC RIDGE IN WAKE TO
BUILD INTO GRTLKS RGN MIDWEEK TO ASSERT DRY/SUBSIDENT AIRMASS
PERSISTING THROUGH LATTER HALF OF WEEK. SHALLOW CAA/925MB THERMAL
TROF AMID FLOW VEERING TO NERLY PEAKS WED AM...THOUGH REBOUND TO
NEAR NORMAL MAX TEMPS ANTICIPATED AMID STRONG INSOLATION AFFORDED BY
DRY AIRMASS/PWAT NEAR 0.50 INCHES. THEREAFTER AIRMASS MODIFIES GRDLY
WARMER NEATH 4 CORNERS RIDGE EXTRUSION NEWD INTO SWRN GRTLKS BY
DY5...THEREAFTER CULMINATING INTO REX BLOCK OF POST TROPICAL
REMNANTS OF ISAAC DY6. WHILE ECMWF HAS UNDERGONE SOME CONSIDERABLE
DEGREE OF VACILLATION IN PRIOR ITERATIONS...FAVOR 26/00 ECMWF WITH
NOTABLE ADHERENCE TO NAM/4KM WRF/OFFICIAL TRACK OF ISAAC IN SHORT
TERM...IN STARK OPPOSITION TO CONFUNDITY OF GFS FAR WRN TRACK INTO
ERN OK. HAVE TEMPERED POPS DY7 SOMEWHAT TOWARD MULTI MODEL BLEND
WITH SLIGHT NUDGE TOWARD LATEST ECMWF IN DEFERENCE TO CONSISTENCY...
PENDING FURTHER ASSESSMENT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
439 AM EDT SUN AUG 26 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT.
TROUGHINESS FROM CLOSED UPPER LOW MOVING TOWARDS HUDSON BAY THIS
MORNING WILL ATTEMPT TO GRAB HOLD OF WEAK BUT MOISTURE LADEN WAVE
CURRENTLY IN SE KANSAS AND PULL IT NE TODAY INTO TONIGHT. LIGHTER
SHOWER ACTIVITY NOTED ACROSS PORTIONS OF WISCONSIN WITH MORE
WIDESPREAD/HEAVIER SHOWERS/STORMS FROM S CNTRL IOWA INTO SW MISSOURI
AND SE KANSAS. NEAR/SHORT TERM MODELS HAVE VARIETY OF SOLUTIONS IN
HANDLING OF THIS ENERGY AND EFFECTS ON THE AREA. PAST SEVERAL RUNS
OF HRRR HAVE SHOWN DEVELOPMENT SHOULD BE UNDERWAY ACROSS WESTERN
ILLINOIS IN AREA LL CONVERGENCE...30 KT LLJ AND PWATS AROUND 2
INCHES. HOWEVER...LITTLE PRECIP NOTED AND NO INDICATIONS OF ANYTHING
IMMINENT. AT THIS POINT...DISCOUNTING (BUT NOT DISCARDING) THIS IDEA
WHICH WOULD BRING IN SHOWERS TO WESTERN AREAS LATER THIS MORNING.
REMAINING MODELS LEAN TOWARDS AWAITING ARRIVAL OF WAVE INTO ILLINOIS
LATER TODAY INTO TONIGHT ALONG A COLD FRONT SET TO MOVE THROUGH
TONIGHT INTO MONDAY. GIVEN BEST DYNAMICS MOVING NORTH OF THE
AREA...WAVE WILL SLOWLY SHEAR OUT AS IT MOVES NORTHEAST.
HOWEVER...GIVEN DEEP MSTR IN PLACE (OVER 2 INCHES FROM OKLAHOMA INTO
SW MISSOURI)...EXPECT CURRENT ACTIVITY TO REMAIN INTACT/EXPAND AS IT
MOVES NORTHEAST. MAJORITY OF MODELS EVENTUALLY FOCUS LLJ INTO
NORTHERN ILLINOIS IN AXIS OF HIGHER PWATS...CAUSING ADDITIONAL
CONVECTION TO BREAK OUT. FROM THIS POINT IS WHERE MODELS DIVERGE
WITH ANYTHING FROM GLANCING BLOW OF SHOWERS IN NW AREAS...TO
WIDESPREAD SHOWERS/EMBEDDED STORMS...TO CONVECTION REMAINING MAINLY
SOUTH OF THE AREA (SOME HINTS OF THIS IN WATER VAPOR WITH GREATEST
MSTR SHIFTING MORE EAST THAN NORTH). DO THINK THAT MOST...IF NOT ALL
AREAS WILL SEE AT LEAST SOME MEASURABLE RAINFALL WITH BASIN AVERAGES
IN THE QUARTER TO HALF INCH RANGE. WITH POTENTIAL FOR MORE CELLULAR
SETUP VS WIDESPREAD AREA OF RAIN/STORMS HAVE OPTED TO CONTINUE WITH
ARRIVAL OF HIGH END CHC POPS NW AREAS LATER THIS
AFTERNOON...EXPANDING TO HIGHER END LIKELY ACROSS MUCH OF THE AREA
BY LATER TONIGHT.
HAVE NUDGED UP POPS SOMEWHAT MONDAY MORNING IN EASTERN AREAS WITH
CONCERNS ABOUT SLOWER DEPARTURE OF ENERGY. IF 3Z SREF WERE TO
VERIFY...SHOWERS/STORMS WOULD REMAIN ACROSS MUCH OF THE AREA THROUGH
MOST OF MONDAY. THIS MODEL IS PRESENTLY AN OUTLIER SO WHILE AT LEAST
CONSIDERED...DISCOUNTED FOR THE TIME BEING WITH DRYING CONDITIONS
FROM NW TO SE THROUGH THE DAY.
TEMPERATURES HAVE SERIOUS BUST POTENTIAL TODAY ACROSS THE AREA. IR
SAT DATA SHOWS CLOUD COVER TO BEGIN TO ARRIVE IN NW AREAS THIS
MORNING AND THEN INCREASING IN COVERAGE/THICKNESS INTO THIS
AFTERNOON. COOLEST HIGHS ARE EXPECTED IN THESE LOCATIONS AS A RESULT
OF THE LIMITED HEATING WITH WARMER TEMPS...CLOSE TO 90 EXPECTED
ACROSS PORTIONS OF NE INDIANA INTO NW OHIO. IF PRECIP DOES INDEED
WAIT UNTIL CLOSER TO THIS EVENING AND HIGH CLOUDS REMAIN THIN
ENOUGH...HIGHS IN THE NW WILL BE TOO COOL AND NEED ADJUSTING. FOR
NOW WILL GENERALLY LEAVE UNTOUCHED. MUGGY NIGHT IN STORE WITH DEWPTS
IN THE UPPER 60S TO AROUND 70 AND LOWS NEAR OR INTO THE 70S MUCH OF
THE NIGHT. ON MONDAY...TEMPS WILL REMAIN AN ISSUE WITH CLEARING
EXPECTED NW WHERE A NICE REBOUND COULD OCCUR GIVEN OVERNIGHT LOWS
ONLY AROUND 70...WITH SE AREAS SLOWER TO CLIMB WITH LINGERING CLOUD
COVER. HAVE KEPT MON/MON NGT LOWS AS IS.
&&
.LONG TERM...
TUESDAY THROUGH SATURDAY. FEW CHNGS WRT LONG TERM. CRNT CNTL PLAINS
SHORTWAVE TO MINOR NEWD AS ASSERTIVE MANITOBA MID TROPOSPHERIC
VORTEX SWEEPS INTO JAMES BAY BY ERLY MONDAY. SFC RIDGE IN WAKE TO
BUILD INTO GRTLKS RGN MIDWEEK TO ASSERT DRY/SUBSIDENT AIRMASS
PERSISTING THROUGH LATTER HALF OF WEEK. SHALLOW CAA/925MB THERMAL
TROF AMID FLOW VEERING TO NERLY PEAKS WED AM...THOUGH REBOUND TO
NEAR NORMAL MAX TEMPS ANTICIPATED AMID STRONG INSOLATION AFFORDED BY
DRY AIRMASS/PWAT NEAR 0.50 INCHES. THEREAFTER AIRMASS MODIFIES GRDLY
WARMER NEATH 4 CORNERS RIDGE EXTRUSION NEWD INTO SWRN GRTLKS BY
DY5...THEREAFTER CULMINATING INTO REX BLOCK OF POST TROPICAL
REMNANTS OF ISAAC DY6. WHILE ECMWF HAS UNDERGONE SOME CONSIDERABLE
DEGREE OF VACILLATION IN PRIOR ITERATIONS...FAVOR 26/00 ECMWF WITH
NOTABLE ADHERENCE TO NAM/4KM WRF/OFFICIAL TRACK OF ISAAC IN SHORT
TERM...IN STARK OPPOSITION TO CONFUNDITY OF GFS FAR WRN TRACK INTO
ERN OK. HAVE TEMPERED POPS DY7 SOMEWHAT TOWARD MULTI MODEL BLEND
WITH SLIGHT NUDGE TOWARD LATEST ECMWF IN DEFERENCE TO CONSISTENCY...
PENDING FURTHER ASSESSMENT.
&&
.AVIATION...06Z TAFS
NO SIG CHANGES TO TAFS WITH LOW TO MEDIUM CONFIDENCE IN EVOLUTION
OF RAIN CHANCES/FLGT IMPACTS AT BOTH SITES LATER THIS AFTERNOON
INTO TONIGHT.
TO START OFF...NO CHANGES MADE PRIOR TO 18Z WITH SOME POTENTIAL
FOR SHALLOW FOG/MIST AT BOTH SITES. TEMP/DEWPT SPREAD ALREADY
DECREASING AT KFWA WITH LARGER DEPRESSION AT KSBN WHICH MAY ALLOW
FOR FOG DEVELOPMENT TO HOLD OFF. AFTER THIS FOCUS WILL TURN TO
PRECIP CHANCES LATE THIS AFTERNOON INTO TONIGHT. CONVECTION
EXPECTED TO DEVELOP ACROSS ILLINOIS AND MAY MOVE INTO INDIANA LATE
AFTERNOON AND ESPECIALLY TONIGHT. TIMING/COVERAGE OF SHOWER/TSTORM
ACTIVITY REMAINS QUESTIONABLE WITH SEVERAL MODELS KEEPING BULK OF
PRECIP CLOSER TO KSBN AND POTENTIALLY NOT UNTIL THE 3 TO 6Z
WINDOW. AT THIS POINT...KFWA WAS LEFT DRY THROUGH 06Z WITH MVFR
VSBY INTRODUCED AT KSBN TOWARDS THE END OF THE FORECAST PERIOD
WHEN MODELS SEEM TO AGREE AT THE BEST POTENTIAL...LIKELY LINGERING
THROUGH 12Z.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...FISHER
LONG TERM...MURPHY
AVIATION...FISHER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1227 PM CDT SUN AUG 26 2012
.AVIATION...
WIDESPREAD RAIN...OCCASIONALLY HEAVY WITH 1/2 TO 1 MILE
VISIBILITIES IN HEAVY RAIN AND FOG...WILL CONTINUE THROUGH 20Z IN
WESTERN SECTIONS OF EASTERN IOWA...NEAR CID...AND DBQ...FARTHER
SOUTHEAST...THIS RAIN EVENT WILL CONTINUE THROUGH 23 TO 00Z THIS
EVENING. CIGS WILL ALSO BE VARIABLE DURING THIS RAIN EVENT...FROM
AROUND 500 FT AGL...TO 2000 FT. SOME BRIEF VFR CIGS ARE ALSO
POSSIBLE...BUT WILL NOT BE EXPLICITLY FORECAST. AFTER RAIN ENDS
TODAY...FROM WEST TO EAST...A WINDOW OF VFR WEATHER FOR A FEW
EVENING HOURS. THEN...AS SKIES CLEAR FROM WEST TO EAST BETWEEN 00Z
AND 03Z...THE MOIST LOW LEVELS STRONGLY SUPPORT DENSE FOG
FORMATION IN ALL AREAS THAT CLEAR OUT. VISIBILITIES ARE FORECAST
FOR LIFR 1/2SM MILE FOR NOW...BUT WILL LIKELY NEED TO BE REFINED
LATER. A SLOW IMPROVEMENT TO MVFR CIGS AND VISIBILITIES IS
FORECAST FOR MONDAY MORNING AFTER 13Z.
ERVIN
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT SUN AUG 26 2012/
SYNOPSIS...
WEAK UPPER LEVEL WESTERLY FLOW CONTINUES OVER NEARLY ALL OF THE
CONUS. CORRESPONDINGLY WEAK 500MB TROUGH SPANS THE PLAINS FROM
SOUTHERN MINNESOTA INTO WEST TEXAS. PLUME OF LOW LEVEL MOISTURE IS
FEEDING FROM THE GULF OF MEXICO INTO THE UPPER MIDWEST...WITH 850MB
DEW POINTS AT OR ABOVE 15C OVER A SIGNIFICANT PORTION OF THE
SOUTHERN PLAINS AND LOWER MS VALLEY. AT THE SURFACE...LOW PRESSURE
IS CENTERED OVER KANSAS CITY THIS MORNING WITH A TROUGH EXTENDING TO
ITS SOUTHWEST...AND THE BEGINNINGS OF A WEAK WARM FRONT DEVELOPING
ACROSS NORTHERN MISSOURI AND SOUTHERN ILLINOIS.
SHORT TERM...TODAY AND TONIGHT...
FIRST WAVE OF SHOWERS ONGOING THIS MORNING OVER NORTHERN PORTIONS OF
THE CWFA...IN A BROAD AREA OF MID LEVEL ISENTROPIC LIFT AROUND
305K. MAIN SHOW DRIVEN BY THE UPPER TROUGH IS NOW KNOCKING ON OUR
DOOR OVER SOUTHCENTRAL IOWA. PRECIPITABLE WATERS ABOVE 2
INCHES...ABOUT 175 PERCENT OF NORMAL...OVER THE ENTIRE CWFA THIS
MORNING SUGGEST HIGHLY EFFICIENT RAINFALL PROCESSES. GIVEN THE WEAK
UPPER FLOW...SYSTEM WILL BE SLOW TO PROGRESS...FURTHER PADDING THE
RAINFALL TOTALS. ALTHOUGH ONSET IS A BIT SLOWER THAN PREVIOUSLY
FORECAST...STILL LOOKS LIKE WE SHOULD SEE WIDESPREAD AMOUNTS NEAR
ONE INCH. MID LEVEL LAPSE RATES SUGGEST POTENTIAL FOR WIDESPREAD
THUNDER IS LOW. HOWEVER...ISOLATED EMBEDDED THUNDER HAS CONTINUED
OVERNIGHT OVER NORTHERN MISSOURI AND WILL MAINTAIN MENTION OF
ISOLATED THUNDER AS THE UPPER FORCING MOVES INTO THE AREA THIS
MORNING.
FAVORED THE RAP AND NAM TODAY AS BOTH HAVE A DECENT HANDLE ON THE
SURFACE FEATURES. BASED ON THE NAM SOLUTION...BROAD SCALE LIFT
CONTINUES THROUGH MOST OF THE DAY AHEAD OF THE SURFACE LOW. SHOULD
SEE PRECIP ENDING FROM WEST TO EAST LATE TODAY AND INTO TONIGHT AS
THE SYSTEM CLEARS THE AREA.
DMD
LONG TERM...MONDAY THROUGH NEXT SATURDAY...
MAINLY DRY WITH NEAR TO ABOVE NORMAL TEMPS AS SFC AND UPPER RIDGING
DOMINATES FOR MUCH OF THE PERIOD.
MON-WED... DRY AND FEW DEGS COOLER WITH LIGHT NORTHERLY WINDS TO
PERSIST FOR MUCH OF THE PERIOD VEERING TO EASTERLY BY WED AS SFC
HIGH SHIFTS THROUGH GREAT LAKES. H85 THERMAL GRADIENT W-E SHOWN
TO RESIDE OVER CWA WITH H85 TEMPS MAINLY IN RANGE OF 14-18C. THESE
VALUES MIXED TO SFC CLOSER TO DRY ADIABATICALLY SUPPORT WIDESPREAD
80S WITH COOLEST READINGS E/NE AND WARMEST S/SW. LOWS NEAR TO
BELOW COOLEST GUIDANCE WITH GOOD RADIATIONAL COOLING SETUP DURING
THE NIGHTS... WITH 50S FOR LOWS FAIRLY COMMON BOTH TUE AND WED AM.
DRY AIR SHOULD PROMOTE LARGE DIURNAL RANGES ON ORDER OF 30-35+ DEGS.
THU-SAT... UPPER LEVEL RIDGE BUILDS INTO REGION BY LATE WEEK AND THEN
FLATTENS. TEMPS ALOFT WARM WITH H85 TEMPS IN THE RANGE OF 20-25C.
BUT MODELS INDICATE WEAK MIXING REGIME WITH SFC RIDGE AXIS IN CLOSE
PROXIMITY... THUS NOT ABLE TO TAP FULL WARMTH AND SPARING US FROM
BAKING. THEREFORE... CONTINUATION OF MAINLY 80S FOR HIGHS. PCPN CHCS
LATE IN EXTENDED DEPENDENT ON MOVEMENT OF ISAAC REMNANTS.
OVERALL... HAVE SERIOUS DOUBTS THAT WE WILL SEE ANY IMPACT FROM
ISAAC DESPITE LATEST GFS AND GEM SOLUTIONS BRINGING REMNANTS
EITHER UP OVER CWA OR JUST GLANCING S/E CWA. TYPICALLY NEED LANDFALL
TO OCCUR IN TX OR WRN LA FOR THESE SYSTEMS TO HAVE ANY IMPACT
FOR OUR CWA. AT 06Z... GFS AND GEM WERE AROUND 3 MB TOO WEAK WITH
ISAAC AND THIS COULD AT LEAST PARTIALLY EXPLAIN THEIR MORE WESTERN
TRACK. IF WE SEE CONTINUED STRENGTHENING TDY TO HURRICANE THEN WOULD
EXPECT ISAAC TO START CURVING... AND IT WOULD SEEM VERY LIKELY THAT
ISAAC WOULD CONNECT WITH EASTERN TROUGH AND GET PULLED NORTHWARD.
THE KEY WILL BE AMOUNT/RATE OF INTENSIFICATION AS THE SLOWER ISAAC
TAKES TO RAMP UP THE MORE AND MORE A WESTERN TRACK WOULD BE POSSIBLE.
HAVE FOLLOWED HPC GUIDANCE CLOSELY LATE IN THE EXTENDED AND WILL HAVE
MAINLY DRY FCST FRI-SAT WITH ISAAC REMNANTS STAYING TO OUR E/SE.
MCCLURE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
ERVIN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
640 AM CDT SUN AUG 26 2012
.AVIATION...
A WEAK LOW PRESSURE SYSTEM WILL BRING PERIODS OF RAINFALL TO THE
LOCAL AREA TODAY AND INTO TONIGHT. CIGS AND VSBYS WILL BE BELOW
MVFR THRESHOLDS FOR MUCH OF TODAY AND WILL DROP BELOW IFR THRESHOLDS
DURING PERIODS OF RAIN. ONCE THE RAIN ENDS TONIGHT...LIGHT WINDS
WILL FOLLOW AND THERE IS POTENTIAL FOR FOG TO DEVELOP IN THE EARLY
MORNING HOURS. DMD
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT SUN AUG 26 2012/
SYNOPSIS...
WEAK UPPER LEVEL WESTERLY FLOW CONTINUES OVER NEARLY ALL OF THE
CONUS. CORRESPONDINGLY WEAK 500MB TROUGH SPANS THE PLAINS FROM
SOUTHERN MINNESOTA INTO WEST TEXAS. PLUME OF LOW LEVEL MOISTURE IS
FEEDING FROM THE GULF OF MEXICO INTO THE UPPER MIDWEST...WITH 850MB
DEW POINTS AT OR ABOVE 15C OVER A SIGNIFICANT PORTION OF THE
SOUTHERN PLAINS AND LOWER MS VALLEY. AT THE SURFACE...LOW PRESSURE
IS CENTERED OVER KANSAS CITY THIS MORNING WITH A TROUGH EXTENDING TO
ITS SOUTHWEST...AND THE BEGINNINGS OF A WEAK WARM FRONT DEVELOPING
ACROSS NORTHERN MISSOURI AND SOUTHERN ILLINOIS.
SHORT TERM...TODAY AND TONIGHT...
FIRST WAVE OF SHOWERS ONGOING THIS MORNING OVER NORTHERN PORTIONS OF
THE CWFA...IN A BROAD AREA OF MID LEVEL ISENTROPIC LIFT AROUND
305K. MAIN SHOW DRIVEN BY THE UPPER TROUGH IS NOW KNOCKING ON OUR
DOOR OVER SOUTHCENTRAL IOWA. PRECIPITABLE WATERS ABOVE 2
INCHES...ABOUT 175 PERCENT OF NORMAL...OVER THE ENTIRE CWFA THIS
MORNING SUGGEST HIGHLY EFFICIENT RAINFALL PROCESSES. GIVEN THE WEAK
UPPER FLOW...SYSTEM WILL BE SLOW TO PROGRESS...FURTHER PADDING THE
RAINFALL TOTALS. ALTHOUGH ONSET IS A BIT SLOWER THAN PREVIOUSLY
FORECAST...STILL LOOKS LIKE WE SHOULD SEE WIDESPREAD AMOUNTS NEAR
ONE INCH. MID LEVEL LAPSE RATES SUGGEST POTENTIAL FOR WIDESPREAD
THUNDER IS LOW. HOWEVER...ISOLATED EMBEDDED THUNDER HAS CONTINUED
OVERNIGHT OVER NORTHERN MISSOURI AND WILL MAINTAIN MENTION OF
ISOLATED THUNDER AS THE UPPER FORCING MOVES INTO THE AREA THIS
MORNING.
FAVORED THE RAP AND NAM TODAY AS BOTH HAVE A DECENT HANDLE ON THE
SURFACE FEATURES. BASED ON THE NAM SOLUTION...BROAD SCALE LIFT
CONTINUES THROUGH MOST OF THE DAY AHEAD OF THE SURFACE LOW. SHOULD
SEE PRECIP ENDING FROM WEST TO EAST LATE TODAY AND INTO TONIGHT AS
THE SYSTEM CLEARS THE AREA.
DMD
LONG TERM...MONDAY THROUGH NEXT SATURDAY...
MAINLY DRY WITH NEAR TO ABOVE NORMAL TEMPS AS SFC AND UPPER RIDGING
DOMINATES FOR MUCH OF THE PERIOD.
MON-WED... DRY AND FEW DEGS COOLER WITH LIGHT NORTHERLY WINDS TO
PERSIST FOR MUCH OF THE PERIOD VEERING TO EASTERLY BY WED AS SFC
HIGH SHIFTS THROUGH GREAT LAKES. H85 THERMAL GRADIENT W-E SHOWN
TO RESIDE OVER CWA WITH H85 TEMPS MAINLY IN RANGE OF 14-18C. THESE
VALUES MIXED TO SFC CLOSER TO DRY ADIABATICALLY SUPPORT WIDESPREAD
80S WITH COOLEST READINGS E/NE AND WARMEST S/SW. LOWS NEAR TO
BELOW COOLEST GUIDANCE WITH GOOD RADIATIONAL COOLING SETUP DURING
THE NIGHTS... WITH 50S FOR LOWS FAIRLY COMMON BOTH TUE AND WED AM.
DRY AIR SHOULD PROMOTE LARGE DIURNAL RANGES ON ORDER OF 30-35+ DEGS.
THU-SAT... UPPER LEVEL RIDGE BUILDS INTO REGION BY LATE WEEK AND THEN
FLATTENS. TEMPS ALOFT WARM WITH H85 TEMPS IN THE RANGE OF 20-25C.
BUT MODELS INDICATE WEAK MIXING REGIME WITH SFC RIDGE AXIS IN CLOSE
PROXIMITY... THUS NOT ABLE TO TAP FULL WARMTH AND SPARING US FROM
BAKING. THEREFORE... CONTINUATION OF MAINLY 80S FOR HIGHS. PCPN CHCS
LATE IN EXTENDED DEPENDENT ON MOVEMENT OF ISAAC REMNANTS.
OVERALL... HAVE SERIOUS DOUBTS THAT WE WILL SEE ANY IMPACT FROM
ISAAC DESPITE LATEST GFS AND GEM SOLUTIONS BRINGING REMNANTS
EITHER UP OVER CWA OR JUST GLANCING S/E CWA. TYPICALLY NEED LANDFALL
TO OCCUR IN TX OR WRN LA FOR THESE SYSTEMS TO HAVE ANY IMPACT
FOR OUR CWA. AT 06Z... GFS AND GEM WERE AROUND 3 MB TOO WEAK WITH
ISAAC AND THIS COULD AT LEAST PARTIALLY EXPLAIN THEIR MORE WESTERN
TRACK. IF WE SEE CONTINUED STRENGTHENING TDY TO HURRICANE THEN WOULD
EXPECT ISAAC TO START CURVING... AND IT WOULD SEEM VERY LIKELY THAT
ISAAC WOULD CONNECT WITH EASTERN TROUGH AND GET PULLED NORTHWARD.
THE KEY WILL BE AMOUNT/RATE OF INTENSIFICATION AS THE SLOWER ISAAC
TAKES TO RAMP UP THE MORE AND MORE A WESTERN TRACK WOULD BE POSSIBLE.
HAVE FOLLOWED HPC GUIDANCE CLOSELY LATE IN THE EXTENDED AND WILL HAVE
MAINLY DRY FCST FRI-SAT WITH ISAAC REMNANTS STAYING TO OUR E/SE.
MCCLURE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
636 AM CDT SUN AUG 26 2012
.AVIATION...
A WEAK LOW PRESSURE SYSTEM WILL BRING PERIODS OF RAINFALL TO THE
LOCAL AREA TODAY AND INTO TONIGHT. CIGS AND VSBYS BE BELOW MVFR
THRESHOLDS FOR MUCH OF TODAY AND WILL DROP BELOW IFR THRESHOLDS
DURING PERIODS OF RAIN. ONCE THE RAIN ENDS TONIGHT...LIGHT WINDS
WILL FOLLOW AND THERE IS POTENTIAL FOR FOG TO DEVELOP IN THE EARLY
MORNING HOURS. DMD
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT SUN AUG 26 2012/
SYNOPSIS...
WEAK UPPER LEVEL WESTERLY FLOW CONTINUES OVER NEARLY ALL OF THE
CONUS. CORRESPONDINGLY WEAK 500MB TROUGH SPANS THE PLAINS FROM
SOUTHERN MINNESOTA INTO WEST TEXAS. PLUME OF LOW LEVEL MOISTURE IS
FEEDING FROM THE GULF OF MEXICO INTO THE UPPER MIDWEST...WITH 850MB
DEW POINTS AT OR ABOVE 15C OVER A SIGNIFICANT PORTION OF THE
SOUTHERN PLAINS AND LOWER MS VALLEY. AT THE SURFACE...LOW PRESSURE
IS CENTERED OVER KANSAS CITY THIS MORNING WITH A TROUGH EXTENDING TO
ITS SOUTHWEST...AND THE BEGINNINGS OF A WEAK WARM FRONT DEVELOPING
ACROSS NORTHERN MISSOURI AND SOUTHERN ILLINOIS.
SHORT TERM...TODAY AND TONIGHT...
FIRST WAVE OF SHOWERS ONGOING THIS MORNING OVER NORTHERN PORTIONS OF
THE CWFA...IN A BROAD AREA OF MID LEVEL ISENTROPIC LIFT AROUND
305K. MAIN SHOW DRIVEN BY THE UPPER TROUGH IS NOW KNOCKING ON OUR
DOOR OVER SOUTHCENTRAL IOWA. PRECIPITABLE WATERS ABOVE 2
INCHES...ABOUT 175 PERCENT OF NORMAL...OVER THE ENTIRE CWFA THIS
MORNING SUGGEST HIGHLY EFFICIENT RAINFALL PROCESSES. GIVEN THE WEAK
UPPER FLOW...SYSTEM WILL BE SLOW TO PROGRESS...FURTHER PADDING THE
RAINFALL TOTALS. ALTHOUGH ONSET IS A BIT SLOWER THAN PREVIOUSLY
FORECAST...STILL LOOKS LIKE WE SHOULD SEE WIDESPREAD AMOUNTS NEAR
ONE INCH. MID LEVEL LAPSE RATES SUGGEST POTENTIAL FOR WIDESPREAD
THUNDER IS LOW. HOWEVER...ISOLATED EMBEDDED THUNDER HAS CONTINUED
OVERNIGHT OVER NORTHERN MISSOURI AND WILL MAINTAIN MENTION OF
ISOLATED THUNDER AS THE UPPER FORCING MOVES INTO THE AREA THIS
MORNING.
FAVORED THE RAP AND NAM TODAY AS BOTH HAVE A DECENT HANDLE ON THE
SURFACE FEATURES. BASED ON THE NAM SOLUTION...BROAD SCALE LIFT
CONTINUES THROUGH MOST OF THE DAY AHEAD OF THE SURFACE LOW. SHOULD
SEE PRECIP ENDING FROM WEST TO EAST LATE TODAY AND INTO TONIGHT AS
THE SYSTEM CLEARS THE AREA.
DMD
LONG TERM...MONDAY THROUGH NEXT SATURDAY...
MAINLY DRY WITH NEAR TO ABOVE NORMAL TEMPS AS SFC AND UPPER RIDGING
DOMINATES FOR MUCH OF THE PERIOD.
MON-WED... DRY AND FEW DEGS COOLER WITH LIGHT NORTHERLY WINDS TO
PERSIST FOR MUCH OF THE PERIOD VEERING TO EASTERLY BY WED AS SFC
HIGH SHIFTS THROUGH GREAT LAKES. H85 THERMAL GRADIENT W-E SHOWN
TO RESIDE OVER CWA WITH H85 TEMPS MAINLY IN RANGE OF 14-18C. THESE
VALUES MIXED TO SFC CLOSER TO DRY ADIABATICALLY SUPPORT WIDESPREAD
80S WITH COOLEST READINGS E/NE AND WARMEST S/SW. LOWS NEAR TO
BELOW COOLEST GUIDANCE WITH GOOD RADIATIONAL COOLING SETUP DURING
THE NIGHTS... WITH 50S FOR LOWS FAIRLY COMMON BOTH TUE AND WED AM.
DRY AIR SHOULD PROMOTE LARGE DIURNAL RANGES ON ORDER OF 30-35+ DEGS.
THU-SAT... UPPER LEVEL RIDGE BUILDS INTO REGION BY LATE WEEK AND THEN
FLATTENS. TEMPS ALOFT WARM WITH H85 TEMPS IN THE RANGE OF 20-25C.
BUT MODELS INDICATE WEAK MIXING REGIME WITH SFC RIDGE AXIS IN CLOSE
PROXIMITY... THUS NOT ABLE TO TAP FULL WARMTH AND SPARING US FROM
BAKING. THEREFORE... CONTINUATION OF MAINLY 80S FOR HIGHS. PCPN CHCS
LATE IN EXTENDED DEPENDENT ON MOVEMENT OF ISAAC REMNANTS.
OVERALL... HAVE SERIOUS DOUBTS THAT WE WILL SEE ANY IMPACT FROM
ISAAC DESPITE LATEST GFS AND GEM SOLUTIONS BRINGING REMNANTS
EITHER UP OVER CWA OR JUST GLANCING S/E CWA. TYPICALLY NEED LANDFALL
TO OCCUR IN TX OR WRN LA FOR THESE SYSTEMS TO HAVE ANY IMPACT
FOR OUR CWA. AT 06Z... GFS AND GEM WERE AROUND 3 MB TOO WEAK WITH
ISAAC AND THIS COULD AT LEAST PARTIALLY EXPLAIN THEIR MORE WESTERN
TRACK. IF WE SEE CONTINUED STRENGTHENING TDY TO HURRICANE THEN WOULD
EXPECT ISAAC TO START CURVING... AND IT WOULD SEEM VERY LIKELY THAT
ISAAC WOULD CONNECT WITH EASTERN TROUGH AND GET PULLED NORTHWARD.
THE KEY WILL BE AMOUNT/RATE OF INTENSIFICATION AS THE SLOWER ISAAC
TAKES TO RAMP UP THE MORE AND MORE A WESTERN TRACK WOULD BE POSSIBLE.
HAVE FOLLOWED HPC GUIDANCE CLOSELY LATE IN THE EXTENDED AND WILL HAVE
MAINLY DRY FCST FRI-SAT WITH ISAAC REMNANTS STAYING TO OUR E/SE.
MCCLURE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
DMD/05/DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
338 AM CDT SUN AUG 26 2012
.SYNOPSIS...
WEAK UPPER LEVEL WESTERLY FLOW CONTINUES OVER NEARLY ALL OF THE
CONUS. CORRESPONDINGLY WEAK 500MB TROUGH SPANS THE PLAINS FROM
SOUTHERN MINNESOTA INTO WEST TEXAS. PLUME OF LOW LEVEL MOISTURE IS
FEEDING FROM THE GULF OF MEXICO INTO THE UPPER MIDWEST...WITH 850MB
DEW POINTS AT OR ABOVE 15C OVER A SIGNIFICANT PORTION OF THE
SOUTHERN PLAINS AND LOWER MS VALLEY. AT THE SURFACE...LOW PRESSURE
IS CENTERED OVER KANSAS CITY THIS MORNING WITH A TROUGH EXTENDING TO
ITS SOUTHWEST...AND THE BEGINNINGS OF A WEAK WARM FRONT DEVELOPING
ACROSS NORTHERN MISSOURI AND SOUTHERN ILLINOIS.
&&
.SHORT TERM...TODAY AND TONIGHT...
FIRST WAVE OF SHOWERS ONGOING THIS MORNING OVER NORTHERN PORTIONS OF
THE CWFA...IN A BROAD AREA OF MID LEVEL ISENTROPIC LIFT AROUND
305K. MAIN SHOW DRIVEN BY THE UPPER TROUGH IS NOW KNOCKING ON OUR
DOOR OVER SOUTHCENTRAL IOWA. PRECIPITABLE WATERS ABOVE 2
INCHES...ABOUT 175 PERCENT OF NORMAL...OVER THE ENTIRE CWFA THIS
MORNING SUGGEST HIGHLY EFFICIENT RAINFALL PROCESSES. GIVEN THE WEAK
UPPER FLOW...SYSTEM WILL BE SLOW TO PROGRESS...FURTHER PADDING THE
RAINFALL TOTALS. ALTHOUGH ONSET IS A BIT SLOWER THAN PREVIOUSLY
FORECAST...STILL LOOKS LIKE WE SHOULD SEE WIDESPREAD AMOUNTS NEAR
ONE INCH. MID LEVEL LAPSE RATES SUGGEST POTENTIAL FOR WIDESPREAD
THUNDER IS LOW. HOWEVER...ISOLATED EMBEDDED THUNDER HAS CONTINUED
OVERNIGHT OVER NORTHERN MISSOURI AND WILL MAINTAIN MENTION OF
ISOLATED THUNDER AS THE UPPER FORCING MOVES INTO THE AREA THIS
MORNING.
FAVORED THE RAP AND NAM TODAY AS BOTH HAVE A DECENT HANDLE ON THE
SURFACE FEATURES. BASED ON THE NAM SOLUTION...BROAD SCALE LIFT
CONTINUES THROUGH MOST OF THE DAY AHEAD OF THE SURFACE LOW. SHOULD
SEE PRECIP ENDING FROM WEST TO EAST LATE TODAY AND INTO TONIGHT AS
THE SYSTEM CLEARS THE AREA.
DMD
.LONG TERM...MONDAY THROUGH NEXT SATURDAY...
MAINLY DRY WITH NEAR TO ABOVE NORMAL TEMPS AS SFC AND UPPER RIDGING
DOMINATES FOR MUCH OF THE PERIOD.
MON-WED... DRY AND FEW DEGS COOLER WITH LIGHT NORTHERLY WINDS TO
PERSIST FOR MUCH OF THE PERIOD VEERING TO EASTERLY BY WED AS SFC
HIGH SHIFTS THROUGH GREAT LAKES. H85 THERMAL GRADIENT W-E SHOWN
TO RESIDE OVER CWA WITH H85 TEMPS MAINLY IN RANGE OF 14-18C. THESE
VALUES MIXED TO SFC CLOSER TO DRY ADIABATICALLY SUPPORT WIDESPREAD
80S WITH COOLEST READINGS E/NE AND WARMEST S/SW. LOWS NEAR TO
BELOW COOLEST GUIDANCE WITH GOOD RADIATIONAL COOLING SETUP DURING
THE NIGHTS... WITH 50S FOR LOWS FAIRLY COMMON BOTH TUE AND WED AM.
DRY AIR SHOULD PROMOTE LARGE DIURNAL RANGES ON ORDER OF 30-35+ DEGS.
THU-SAT... UPPER LEVEL RIDGE BUILDS INTO REGION BY LATE WEEK AND THEN
FLATTENS. TEMPS ALOFT WARM WITH H85 TEMPS IN THE RANGE OF 20-25C.
BUT MODELS INDICATE WEAK MIXING REGIME WITH SFC RIDGE AXIS IN CLOSE
PROXIMITY... THUS NOT ABLE TO TAP FULL WARMTH AND SPARING US FROM
BAKING. THEREFORE... CONTINUATION OF MAINLY 80S FOR HIGHS. PCPN CHCS
LATE IN EXTENDED DEPENDENT ON MOVEMENT OF ISAAC REMNANTS.
OVERALL... HAVE SERIOUS DOUBTS THAT WE WILL SEE ANY IMPACT FROM
ISAAC DESPITE LATEST GFS AND GEM SOLUTIONS BRINGING REMNANTS
EITHER UP OVER CWA OR JUST GLANCING S/E CWA. TYPICALLY NEED LANDFALL
TO OCCUR IN TX OR WRN LA FOR THESE SYSTEMS TO HAVE ANY IMPACT
FOR OUR CWA. AT 06Z... GFS AND GEM WERE AROUND 3 MB TOO WEAK WITH
ISAAC AND THIS COULD AT LEAST PARTIALLY EXPLAIN THEIR MORE WESTERN
TRACK. IF WE SEE CONTINUED STRENGTHENING TDY TO HURRICANE THEN WOULD
EXPECT ISAAC TO START CURVING... AND IT WOULD SEEM VERY LIKELY THAT
ISAAC WOULD CONNECT WITH EASTERN TROUGH AND GET PULLED NORTHWARD.
THE KEY WILL BE AMOUNT/RATE OF INTENSIFICATION AS THE SLOWER ISAAC
TAKES TO RAMP UP THE MORE AND MORE A WESTERN TRACK WOULD BE POSSIBLE.
HAVE FOLLOWED HPC GUIDANCE CLOSELY LATE IN THE EXTENDED AND WILL HAVE
MAINLY DRY FCST FRI-SAT WITH ISAAC REMNANTS STAYING TO OUR E/SE.
MCCLURE
&&
.AVIATION...
A WEAK LOW PRESSURE SYSTEM WILL BRING WIDESPREAD RAINFALL TO THE
LOCAL AREA TODAY. CIGS AND VSBYS ARE EXPECTED TO DROP BELOW IFR
THRESHOLDS BY 18Z AT AREA TAF SITES. CONDITIONS WILL IMPROVE AGAIN
FROM WEST TO EAST AFTER 00Z. DMD
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
DMD/MCCLURE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
120 PM MDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 117 PM MDT SUN AUG 26 2012
TEMPERATURES CLIMBING TO NEAR PREVIOUSLY EXPECTED MAXES. SO RAISED
MAXES AREA WIDE.
UPDATE ISSUED AT 919 AM MDT SUN AUG 26 2012
JUST COMPLETED AN UPDATE. MAIN REASON FOR THE EXPIRATION OF THE
DENSE FOG ADVISORY/ENDING OF FOG. THEN ADJUSTED SKY COVER AND
DEWPOINTS BASED ON LATEST DATA AND TRENDS. ALSO UPDATED WINDS
THROUGH TOMORROW BASED ON LATEST TRENDS AND NAM DOING VERY WELL AT
THIS TIME. TODAYS LOOK CLOSE/IN GOOD SHAPE AND DID NOT MAKE ANY
ADJUSTMENTS. PRECIPITATION FORECAST FOR LATER THIS AFTERNOON AND
THIS EVENING ALSO LOOKS FINE.
UPDATE ISSUED AT 540 AM MDT SUN AUG 26 2012
UPDATE SENT TO INCLUDE GRAHAM...NORTON AND DECATUR COUNTIES TO THE
DENSE FOG ADVISORY.
UPDATE ISSUED AT 500 AM MDT SUN AUG 26 2012
HAVE ISSUED A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW
COUNTIES THROUGH 9 AM MDT (10 AM CDT). VISIBILITIES AT KMCK 1/4
MILE OR LESS. LATEST RUC HAS A GOOD HANDLE ON THIS AND WITH LIGHT
WINDS EXPECT THE FOG TO DRIFT INTO HITCHCOCK COUNTY WITHIN THE
NEXT FEW HOURS. WILL HAVE TO WATCH THE ATWOOD AND OBERLIN AREAS
FOR POSSIBLE HEADLINE GIVEN SIMILAR CONDITIONS. WILL WAIT FOR CO-
OP REPORTS AND DAYLIGHT TO VIEW WEB CAMS BEFORE MAKING AND FURTHER
ADJUSTMENTS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 215 AM MDT SUN AUG 26 2012
TODAY-TONIGHT...AT 08Z THIS MORNING STRATUS AND FOG WERE JUST
EAST OF THE FORECAST AREA BUT MOVING TOWARD THE WEST AT 15 MPH.
THIS WOULD PUT IT AS FAR WEST AS MCCOOK TO OBERLIN AND WAKEENEY BY
12Z THIS MORNING. VISIBILITIES ARE IN THE 1/4 MILE RANGE ARE
COMMON PER OBSERVATIONS. WILL CONTINUE TO WATCH JUST HOW FAR WEST
IT GETS AND SHOULD IT REACH THE FORECAST AREA A DENSE FOG ADVISORY
WILL BE NEEDED.
OTHERWISE OTHER CONCERN IS ON TIMING OF A FEW THUNDERSTORMS WHICH
SHOULD REACH THE WESTERN 1/4 OF THE AREA (MAINLY FAR EASTERN
COLORADO) BY LATE IN THE AFTERNOON. THESE APPEAR TO BE DIURNALLY
DRIVEN WITHIN AN AXIS OF 700-300 MOISTURE AND AM THINKING THAT ANY
STORMS THAT DO DEVELOP WILL DISSIPATE SHORTLY AFTER SUNSET. HIGH
TEMPERATURES TODAY UPPER 80S TO LOW 90S. LOWS TONIGHT UPPER 50S TO
LOW 60S.
MONDAY-TUESDAY NIGHT...UPPER RIDGE TO BUILD OVER COLORADO THROUGH
THE PERIOD. BREEZY SOUTH TO SOUTHEAST WINDS EXPECTED DURING THE
DAY WITH HIGH TEMPERATURES IN THE LOW TO MID 90S BOTH DAYS. LOWS
UPPER 50S TO LOW 60S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 215 AM MDT SUN AUG 26 2012
THE H5 RIDGE THAT WILL DEVELOP EARLIER IN THE PERIOD IS EXPECTED
TO PERSIST UNTIL NEAR THE MIDDLE OF THE EXTENDED RANGE PERIOD WHEN
A WEAK FRONTAL ZONE MAY AFFECT THE TRI-STATE REGION. CONDITIONS
WILL BE HOT AND DRY WEDNESDAY AND THURSDAY AS THE H5 RIDGE
GRADUALLY MOVES EAST AS A TROUGH ENTERS THE PACIFIC NORTHWEST.
LATE THURSDAY A FRONTAL BOUNDARY BEGINS TO FORM THROUGH THE UPPER
HIGH PLAINS AND MOVE EAST DURING THE WEEKEND. FROM LOOKING AT THE
PAST FEW DAYS OF MODEL RUNS THIS FEATURE HAS CONSISTENT...BUT ITS
SPATIAL...TEMPORAL ...AND STRENGTH QUALITIES HAVE BEEN ALL OVER
THE MAP. THIS IS LIKELY DUE TO BOTH THE MODEL HANDLING OF THE
TROUGH DIGGING IN TO THE PACIFIC NORTHWEST AND TROPICAL STORM
ISAAC. FOR NOW HAVE INCLUDED MINIMAL SLIGHT CHANCE POPS ON FRIDAY
EVENING FOR THE NORTHWESTERN PART OF THE CWA...WITH DRY CONDITIONS
FORECAST FOR THE REST OF THE PERIOD. TEMPERATURES OVER THE PERIOD
WILL BE WARMER THAN AVERAGE...WITH HIGHS IN THE MID TO LOWER 90S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1131 AM MDT SUN AUG 26 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. ISOLATED
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON IN
EASTERN COLORADO AND ARE EXPECTED TO STAY WEST OF KGLD. LEE TROUGH
IS EXPECTED TO STRENGTHEN LATER TONIGHT INTO TOMORROW. THIS WILL
CAUSE SOUTHERLY WINDS TO STRENGTHEN AND BECOME GUSTY AFTER THE SUN
COMES UP ON MONDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...JJM
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1133 AM MDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 919 AM MDT SUN AUG 26 2012
JUST COMPLETED AN UPDATE. MAIN REASON FOR THE EXPIRATION OF THE
DENSE FOG ADVISORY/ENDING OF FOG. THEN ADJUSTED SKY COVER AND
DEWPOINTS BASED ON LATEST DATA AND TRENDS. ALSO UPDATED WINDS
THROUGH TOMORROW BASED ON LATEST TRENDS AND NAM DOING VERY WELL AT
THIS TIME. TODAYS LOOK CLOSE/IN GOOD SHAPE AND DID NOT MAKE ANY
ADJUSTMENTS. PRECIPITATION FORECAST FOR LATER THIS AFTERNOON AND
THIS EVENING ALSO LOOKS FINE.
UPDATE ISSUED AT 540 AM MDT SUN AUG 26 2012
UPDATE SENT TO INCLUDE GRAHAM...NORTON AND DECATUR COUNTIES TO THE
DENSE FOG ADVISORY.
UPDATE ISSUED AT 500 AM MDT SUN AUG 26 2012
HAVE ISSUED A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW
COUNTIES THROUGH 9 AM MDT (10 AM CDT). VISIBILITIES AT KMCK 1/4
MILE OR LESS. LATEST RUC HAS A GOOD HANDLE ON THIS AND WITH LIGHT
WINDS EXPECT THE FOG TO DRIFT INTO HITCHCOCK COUNTY WITHIN THE
NEXT FEW HOURS. WILL HAVE TO WATCH THE ATWOOD AND OBERLIN AREAS
FOR POSSIBLE HEADLINE GIVEN SIMILAR CONDITIONS. WILL WAIT FOR CO-
OP REPORTS AND DAYLIGHT TO VIEW WEB CAMS BEFORE MAKING AND FURTHER
ADJUSTMENTS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 215 AM MDT SUN AUG 26 2012
TODAY-TONIGHT...AT 08Z THIS MORNING STRATUS AND FOG WERE JUST
EAST OF THE FORECAST AREA BUT MOVING TOWARD THE WEST AT 15 MPH.
THIS WOULD PUT IT AS FAR WEST AS MCCOOK TO OBERLIN AND WAKEENEY BY
12Z THIS MORNING. VISIBILITIES ARE IN THE 1/4 MILE RANGE ARE
COMMON PER OBSERVATIONS. WILL CONTINUE TO WATCH JUST HOW FAR WEST
IT GETS AND SHOULD IT REACH THE FORECAST AREA A DENSE FOG ADVISORY
WILL BE NEEDED.
OTHERWISE OTHER CONCERN IS ON TIMING OF A FEW THUNDERSTORMS WHICH
SHOULD REACH THE WESTERN 1/4 OF THE AREA (MAINLY FAR EASTERN
COLORADO) BY LATE IN THE AFTERNOON. THESE APPEAR TO BE DIURNALLY
DRIVEN WITHIN AN AXIS OF 700-300 MOISTURE AND AM THINKING THAT ANY
STORMS THAT DO DEVELOP WILL DISSIPATE SHORTLY AFTER SUNSET. HIGH
TEMPERATURES TODAY UPPER 80S TO LOW 90S. LOWS TONIGHT UPPER 50S TO
LOW 60S.
MONDAY-TUESDAY NIGHT...UPPER RIDGE TO BUILD OVER COLORADO THROUGH
THE PERIOD. BREEZY SOUTH TO SOUTHEAST WINDS EXPECTED DURING THE
DAY WITH HIGH TEMPERATURES IN THE LOW TO MID 90S BOTH DAYS. LOWS
UPPER 50S TO LOW 60S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 215 AM MDT SUN AUG 26 2012
THE H5 RIDGE THAT WILL DEVELOP EARLIER IN THE PERIOD IS EXPECTED
TO PERSIST UNTIL NEAR THE MIDDLE OF THE EXTENDED RANGE PERIOD WHEN
A WEAK FRONTAL ZONE MAY AFFECT THE TRI-STATE REGION. CONDITIONS
WILL BE HOT AND DRY WEDNESDAY AND THURSDAY AS THE H5 RIDGE
GRADUALLY MOVES EAST AS A TROUGH ENTERS THE PACIFIC NORTHWEST.
LATE THURSDAY A FRONTAL BOUNDARY BEGINS TO FORM THROUGH THE UPPER
HIGH PLAINS AND MOVE EAST DURING THE WEEKEND. FROM LOOKING AT THE
PAST FEW DAYS OF MODEL RUNS THIS FEATURE HAS CONSISTENT...BUT ITS
SPATIAL...TEMPORAL ...AND STRENGTH QUALITIES HAVE BEEN ALL OVER
THE MAP. THIS IS LIKELY DUE TO BOTH THE MODEL HANDLING OF THE
TROUGH DIGGING IN TO THE PACIFIC NORTHWEST AND TROPICAL STORM
ISAAC. FOR NOW HAVE INCLUDED MINIMAL SLIGHT CHANCE POPS ON FRIDAY
EVENING FOR THE NORTHWESTERN PART OF THE CWA...WITH DRY CONDITIONS
FORECAST FOR THE REST OF THE PERIOD. TEMPERATURES OVER THE PERIOD
WILL BE WARMER THAN AVERAGE...WITH HIGHS IN THE MID TO LOWER 90S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1131 AM MDT SUN AUG 26 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. ISOLATED
THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON IN
EASTERN COLORADO AND ARE EXPECTED TO STAY WEST OF KGLD. LEE TROUGH
IS EXPECTED TO STRENGTHEN LATER TONIGHT INTO TOMORROW. THIS WILL
CAUSE SOUTHERLY WINDS TO STRENGTHEN AND BECOME GUSTY AFTER THE SUN
COMES UP ON MONDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...JJM
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1208 PM CDT SUN AUG 26 2012
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1206 PM CDT SUN AUG 26 2012
AT 12Z SUNDAY A 500MB RIDGE EXTENDED FROM NEW MEXICO ACROSS
WESTERN WYOMING AND WESTERN MONTANA INTO ALBERTA CANADA. AN UPPER
LEVEL LOW WAS LOCATED JUST OFF THE COAST OF WASHINGTON AND OREGON.
700MB TEMPERATURES THIS MORNING VARIED FROM 11C AT DODGE CITY TO
15C AT DENVER. THE BETTER 700MB MOISTURE STRETCHED FROM SOUTHERN
IOWA INTO NORTH CENTRAL TEXAS. AT THE SURFACE A COLD FRONT
EXTENDED FROM NORTHERN MISSOURI INTO SOUTHWEST OKLAHOMA. AN AREA
OF HIGH PRESSURE AT 12Z SUNDAY APPEARS CENTERED OVER SOUTHWEST
NEBRASKA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 336 AM CDT SUN AUG 26 2012
IN THE VERY SHORT TERM...LOW STRATUS AND FOG WILL BE THE MAIN ISSUE
ON THE AVIATION SIDE OF THINGS. THE GRIDS ALREADY REFLECT
DEVELOPMENT OF CLOUDS AND PATCHY FOG...BUT WILL TRIM BACK THE
WESTERN EDGE OF THIS (ROUGHLY DIGHTON TO DODGE CITY TO COLDWATER
LINE) PER GUIDANCE FROM THE LATEST RUNS OF THE HRRR MODEL AS WELL AS
TRENDS ON SATELLITE. THE FOG AND STRATUS PROBABLY WONT EVEN MAKE IT
THAT FAR WEST. THE REST OF THE FORECAST FOR TODAY AND TONIGHT IS
FAIRLY STRAIGHT FORWARD UNDER THE MID LEVEL RIDGE AXIS. HIGHS TODAY
WILL BE UPPER 80S TO NEAR 90 AS DIRECT INSOLATION WILL PREVAIL.
SURFACE WINDS WILL BEGIN TO RESPOND TO LOWERING PRESSURE OUT WEST
OVER THE HIGHER TERRAIN...BUT MAINLY ACROSS THE WESTERN COUNTIES
CLOSE TO THE COLORADO BORDER (WEST OF HIGHWAY 83). TONIGHT...ANOTHER
CLEAR AND (NEAR) CALM NIGHT IS EXPECTED WITH LOWS IN THE LOWER TO
MID 60S. A PATCHY AREA OF LIGHT FOG WILL PROBABLY DEVELOP AGAIN IN
LOW LYING AREAS GIVEN IDEAL RADIATIONAL COOLING AND MOIST
GROUND...BUT THE COVERAGE OF ANY FOG DOES NOT REALLY WARRANT
INCLUSION IN GRIDS AT THIS TIME.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 123 AM CDT SUN AUG 26 2012
A RELATIVELY DRY PERIOD IS EXPECTED ACROSS WESTERN KANSAS AS MEDIUM
RANGE MODELS CONTINUE TO INDICATE A LARGE UPPER LEVEL RIDGE OF HIGH
PRESSURE PREVAILING ACROSS THE COLORADO ROCKIES AND THE WESTERN HIGH
PLAINS THROUGH AT LEAST MID WEEK. A GRADUAL WARMING TREND IS LIKELY
THROUGH AT LEAST WEDNESDAY AS A LEE SIDE TROUGH OF LOW PRESSURE
HELPS INFLUENCE A LOW LEVEL SOUTHERLY FLOW ACROSS WESTERN KANSAS
THROUGH MUCH OF THE PERIOD. FOR MONDAY, THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES RANGING FROM JUST ABOVE 20C ACROSS CENTRAL KANSAS
TO JUST ABOVE 25C NEAR THE COLORADO BORDER. ALONG WITH PLENTY OF
SUNSHINE, LOOK FOR HIGHS NEAR TO JUST ABOVE 90F MONDAY AFTERNOON.
THE WARMING TREND WILL CONTINUE WITH HIGHS EXPECTED UP INTO THE LOW
TO MID 90S(F) THROUGH AT LEAST THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1206 PM CDT SUN AUG 26 2012
AN AREA OF HIGH PRESSURE AT THE SURFACE WILL SLOWLY MOVE INTO
EASTERN KANSAS OVERNIGHT. LIGHT WINDS WILL PERSIST AND GRADUALLY
BECOME SOUTHEAST AT LESS THAN 10 KNOTS AFTER 00Z MONDAY. CLEAR
SKIES COMBINED WITH LIGHT WINDS MAY ONCE AGAIN GIVE WAY TO SOME
PATCHY FOG TOWARDS DAYBREAK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 88 62 91 62 / 0 10 0 0
GCK 90 61 92 61 / 0 10 0 0
EHA 90 62 92 61 / 0 10 0 0
LBL 88 62 92 62 / 0 10 0 0
HYS 88 63 92 61 / 0 10 0 0
P28 87 66 93 64 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
922 AM MDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 919 AM MDT SUN AUG 26 2012
JUST COMPLETED AN UPDATE. MAIN REASON FOR THE EXPIRATION OF THE
DENSE FOG ADVISORY/ENDING OF FOG. THEN ADJUSTED SKY COVER AND
DEWPOINTS BASED ON LATEST DATA AND TRENDS. ALSO UPDATED WINDS
THROUGH TOMORROW BASED ON LATEST TRENDS AND NAM DOING VERY WELL AT
THIS TIME. TODAYS LOOK CLOSE/IN GOOD SHAPE AND DID NOT MAKE ANY
ADJUSTMENTS. PRECIPITATION FORECAST FOR LATER THIS AFTERNOON AND
THIS EVENING ALSO LOOKS FINE.
UPDATE ISSUED AT 540 AM MDT SUN AUG 26 2012
UPDATE SENT TO INCLUDE GRAHAM...NORTON AND DECATUR COUNTIES TO THE
DENSE FOG ADVISORY.
UPDATE ISSUED AT 500 AM MDT SUN AUG 26 2012
HAVE ISSUED A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW
COUNTIES THROUGH 9 AM MDT (10 AM CDT). VISIBILITIES AT KMCK 1/4
MILE OR LESS. LATEST RUC HAS A GOOD HANDLE ON THIS AND WITH LIGHT
WINDS EXPECT THE FOG TO DRIFT INTO HITCHCOCK COUNTY WITHIN THE
NEXT FEW HOURS. WILL HAVE TO WATCH THE ATWOOD AND OBERLIN AREAS
FOR POSSIBLE HEADLINE GIVEN SIMILAR CONDITIONS. WILL WAIT FOR CO-
OP REPORTS AND DAYLIGHT TO VIEW WEB CAMS BEFORE MAKING AND FURTHER
ADJUSTMENTS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 215 AM MDT SUN AUG 26 2012
TODAY-TONIGHT...AT 08Z THIS MORNING STRATUS AND FOG WERE JUST
EAST OF THE FORECAST AREA BUT MOVING TOWARD THE WEST AT 15 MPH.
THIS WOULD PUT IT AS FAR WEST AS MCCOOK TO OBERLIN AND WAKEENEY BY
12Z THIS MORNING. VISIBILITIES ARE IN THE 1/4 MILE RANGE ARE
COMMON PER OBSERVATIONS. WILL CONTINUE TO WATCH JUST HOW FAR WEST
IT GETS AND SHOULD IT REACH THE FORECAST AREA A DENSE FOG ADVISORY
WILL BE NEEDED.
OTHERWISE OTHER CONCERN IS ON TIMING OF A FEW THUNDERSTORMS WHICH
SHOULD REACH THE WESTERN 1/4 OF THE AREA (MAINLY FAR EASTERN
COLORADO) BY LATE IN THE AFTERNOON. THESE APPEAR TO BE DIURNALLY
DRIVEN WITHIN AN AXIS OF 700-300 MOISTURE AND AM THINKING THAT ANY
STORMS THAT DO DEVELOP WILL DISSIPATE SHORTLY AFTER SUNSET. HIGH
TEMPERATURES TODAY UPPER 80S TO LOW 90S. LOWS TONIGHT UPPER 50S TO
LOW 60S.
MONDAY-TUESDAY NIGHT...UPPER RIDGE TO BUILD OVER COLORADO THROUGH
THE PERIOD. BREEZY SOUTH TO SOUTHEAST WINDS EXPECTED DURING THE
DAY WITH HIGH TEMPERATURES IN THE LOW TO MID 90S BOTH DAYS. LOWS
UPPER 50S TO LOW 60S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 215 AM MDT SUN AUG 26 2012
THE H5 RIDGE THAT WILL DEVELOP EARLIER IN THE PERIOD IS EXPECTED
TO PERSIST UNTIL NEAR THE MIDDLE OF THE EXTENDED RANGE PERIOD WHEN
A WEAK FRONTAL ZONE MAY AFFECT THE TRI-STATE REGION. CONDITIONS
WILL BE HOT AND DRY WEDNESDAY AND THURSDAY AS THE H5 RIDGE
GRADUALLY MOVES EAST AS A TROUGH ENTERS THE PACIFIC NORTHWEST.
LATE THURSDAY A FRONTAL BOUNDARY BEGINS TO FORM THROUGH THE UPPER
HIGH PLAINS AND MOVE EAST DURING THE WEEKEND. FROM LOOKING AT THE
PAST FEW DAYS OF MODEL RUNS THIS FEATURE HAS CONSISTENT...BUT ITS
SPATIAL...TEMPORAL ...AND STRENGTH QUALITIES HAVE BEEN ALL OVER
THE MAP. THIS IS LIKELY DUE TO BOTH THE MODEL HANDLING OF THE
TROUGH DIGGING IN TO THE PACIFIC NORTHWEST AND TROPICAL STORM
ISAAC. FOR NOW HAVE INCLUDED MINIMAL SLIGHT CHANCE POPS ON FRIDAY
EVENING FOR THE NORTHWESTERN PART OF THE CWA...WITH DRY CONDITIONS
FORECAST FOR THE REST OF THE PERIOD. TEMPERATURES OVER THE PERIOD
WILL BE WARMER THAN AVERAGE...WITH HIGHS IN THE MID TO LOWER 90S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 503 AM MDT SUN AUG 26 2012
DENSE FOG OF 1/4SM VISIBILITY WILL PERSIST THROUGH THE FIRST FEW
HOURS OF THE TAF AS PART OF A LARGE AREA OF DENSE FOG IN SOUTHERN
NEBRASKA AND NORTH CENTRAL KANSAS...WITH IFR CONDITIONS LASTING
UNTIL ABOUT 15Z. FOLLOWING THIS CONDITIONS WILL RAPIDLY IMPROVE TO
IFR CONDITIONS THROUGH THE REST OF THE PERIOD WITH CLEAR SKIES AND
A LIGHT SOUTH-SOUTHEAST WIND.
FOR GLD SOME PATCHY FOG IS EXPECTED THIS MORNING BUT IFR
CONDITIONS ARE NOT EXPECTED TO DEVELOP. ANY FOG THAT DOES DEVELOP WILL
QUICKLY DISSIPATE BY 14Z...AND CONDITIONS WILL REMAIN VFR FOR THE
REST OF THE PERIOD. CLEAR SKIES AND SOUTH-SOUTHEAST WINDS GUSTING
TO 20KTS WILL BE PREVAILING THIS AFTERNOON...WITH WEAKER WINDS
DURING THE OVERNIGHT HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
542 AM MDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 540 AM MDT SUN AUG 26 2012
UPDATE SENT TO INCLUDE GRAHAM...NORTON AND DECATUR COUNTIES TO THE
DENSE FOG ADVISORY.
UPDATE ISSUED AT 500 AM MDT SUN AUG 26 2012
HAVE ISSUED A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW
COUNTIES THROUGH 9 AM MDT (10 AM CDT). VISIBILITIES AT KMCK 1/4
MILE OR LESS. LATEST RUC HAS A GOOD HANDLE ON THIS AND WITH LIGHT
WINDS EXPECT THE FOG TO DRIFT INTO HITCHCOCK COUNTY WITHIN THE
NEXT FEW HOURS. WILL HAVE TO WATCH THE ATWOOD AND OBERLIN AREAS
FOR POSSIBLE HEADLINE GIVEN SIMILAR CONDITIONS. WILL WAIT FOR CO-
OP REPORTS AND DAYLIGHT TO VIEW WEB CAMS BEFORE MAKING AND FURTHER
ADJUSTMENTS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 215 AM MDT SUN AUG 26 2012
TODAY-TONIGHT...AT 08Z THIS MORNING STRATUS AND FOG WERE JUST
EAST OF THE FORECAST AREA BUT MOVING TOWARD THE WEST AT 15 MPH.
THIS WOULD PUT IT AS FAR WEST AS MCCOOK TO OBERLIN AND WAKEENEY BY
12Z THIS MORNING. VISIBILITIES ARE IN THE 1/4 MILE RANGE ARE
COMMON PER OBSERVATIONS. WILL CONTINUE TO WATCH JUST HOW FAR WEST
IT GETS AND SHOULD IT REACH THE FORECAST AREA A DENSE FOG ADVISORY
WILL BE NEEDED.
OTHERWISE OTHER CONCERN IS ON TIMING OF A FEW THUNDERSTORMS WHICH
SHOULD REACH THE WESTERN 1/4 OF THE AREA (MAINLY FAR EASTERN
COLORADO) BY LATE IN THE AFTERNOON. THESE APPEAR TO BE DIURNALLY
DRIVEN WITHIN AN AXIS OF 700-300 MOISTURE AND AM THINKING THAT ANY
STORMS THAT DO DEVELOP WILL DISSIPATE SHORTLY AFTER SUNSET. HIGH
TEMPERATURES TODAY UPPER 80S TO LOW 90S. LOWS TONIGHT UPPER 50S TO
LOW 60S.
MONDAY-TUESDAY NIGHT...UPPER RIDGE TO BUILD OVER COLORADO THROUGH
THE PERIOD. BREEZY SOUTH TO SOUTHEAST WINDS EXPECTED DURING THE
DAY WITH HIGH TEMPERATURES IN THE LOW TO MID 90S BOTH DAYS. LOWS
UPPER 50S TO LOW 60S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 215 AM MDT SUN AUG 26 2012
THE H5 RIDGE THAT WILL DEVELOP EARLIER IN THE PERIOD IS EXPECTED
TO PERSIST UNTIL NEAR THE MIDDLE OF THE EXTENDED RANGE PERIOD WHEN
A WEAK FRONTAL ZONE MAY AFFECT THE TRI-STATE REGION. CONDITIONS
WILL BE HOT AND DRY WEDNESDAY AND THURSDAY AS THE H5 RIDGE
GRADUALLY MOVES EAST AS A TROUGH ENTERS THE PACIFIC NORTHWEST.
LATE THURSDAY A FRONTAL BOUNDARY BEGINS TO FORM THROUGH THE UPPER
HIGH PLAINS AND MOVE EAST DURING THE WEEKEND. FROM LOOKING AT THE
PAST FEW DAYS OF MODEL RUNS THIS FEATURE HAS CONSISTENT...BUT ITS
SPATIAL...TEMPORAL ...AND STRENGTH QUALITIES HAVE BEEN ALL OVER
THE MAP. THIS IS LIKELY DUE TO BOTH THE MODEL HANDLING OF THE
TROUGH DIGGING IN TO THE PACIFIC NORTHWEST AND TROPICAL STORM
ISAAC. FOR NOW HAVE INCLUDED MINIMAL SLIGHT CHANCE POPS ON FRIDAY
EVENING FOR THE NORTHWESTERN PART OF THE CWA...WITH DRY CONDITIONS
FORECAST FOR THE REST OF THE PERIOD. TEMPERATURES OVER THE PERIOD
WILL BE WARMER THAN AVERAGE...WITH HIGHS IN THE MID TO LOWER 90S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 503 AM MDT SUN AUG 26 2012
DENSE FOG OF 1/4SM VISIBILITY WILL PERSIST THROUGH THE FIRST FEW
HOURS OF THE TAF AS PART OF A LARGE AREA OF DENSE FOG IN SOUTHERN
NEBRASKA AND NORTH CENTRAL KANSAS...WITH IFR CONDITIONS LASTING
UNTIL ABOUT 15Z. FOLLOWING THIS CONDITIONS WILL RAPIDLY IMPROVE TO
IFR CONDITIONS THROUGH THE REST OF THE PERIOD WITH CLEAR SKIES AND
A LIGHT SOUTH-SOUTHEAST WIND.
FOR GLD SOME PATCHY FOG IS EXPECTED THIS MORNING BUT IFR
CONDITIONS ARE NOT EXPECTED TO DEVELOP. ANY FOG THAT DOES DEVELOP WILL
QUICKLY DISSIPATE BY 14Z...AND CONDITIONS WILL REMAIN VFR FOR THE
REST OF THE PERIOD. CLEAR SKIES AND SOUTH-SOUTHEAST WINDS GUSTING
TO 20KTS WILL BE PREVAILING THIS AFTERNOON...WITH WEAKER WINDS
DURING THE OVERNIGHT HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ003-004-
016.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ080-081.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
614 AM CDT SUN AUG 26 2012
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 336 AM CDT SUN AUG 26 2012
ON THE SYNOPTIC SCALE...THE MID LEVEL TROUGH THAT BROUGHT ALL THE
RECENT RAINS EXTENDED FROM CENTRAL IOWA TO EASTERN KANSAS TO
NORTHWEST TEXAS EARLY THIS MORNING. SEVERAL THUNDERSTORM CLUSTERS
THRIVED THROUGH THE NIGHT ALONG THE TROUGH AXIS...PARTICULARLY FROM
NORTHERN OKLAHOMA INTO SOUTHEASTERN KANSAS. WATER VAPOR LOOP AS OF
08Z SHOWED SIGNIFICANT MID LEVEL DRYING IN THE WAKE OF THIS TROUGH
AXIS WITH SHORT WAVE RIDGING BUILDING IN ITS WAKE. ALSO IN ITS WAKE
IS A RATHER NON-EXISTENT MEAN SEA LEVEL PRESSURE FIELD WITH THE MSLP
ANALYSIS RATHER ISOBARIC IN NATURE AS MSLP WAS 1013 OR 1014MB FROM
WESTERN KANSAS INTO NEBRASKA, WESTERN IOWA, AND THE DAKOTAS. THIS
RESULTED IN WIDESPREAD CALM OR NEARLY CALM WINDS WITH RESIDUAL
MOISTURE REMNANT FROM BOTH THE RECENT RAINS AND INFLUX OF GULF OF
MEXICO MOISTURE INTO THE AREA AHEAD OF THE TROUGH WHICH WAS NOT
PUSHED OUT OF HERE WITH NO COLD FRONT. A BAROCLINIC WAVE WHICH DID
PASS ACROSS THE SOUTHERN CANADIAN PRAIRIES DID PUSH A COLD FRONT
SOUTH YESTERDAY BUT STALLED OUT, WEAKENED, AND ULTIMATELY DIED OVER
THE SANDHILLS OF NEBRASKA. AS OF 0815Z...THE 11-3.9 MICRON
SATELLITE LOOP CONFIRMED THE DEVELOPMENT OF LOW STRATUS AND FOG
ACROSS NORTH-CENTRAL KANSAS WHICH WAS PUSHING TOWARD THE HAYS AREA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 336 AM CDT SUN AUG 26 2012
IN THE VERY SHORT TERM...LOW STRATUS AND FOG WILL BE THE MAIN ISSUE
ON THE AVIATION SIDE OF THINGS. THE GRIDS ALREADY REFLECT
DEVELOPMENT OF CLOUDS AND PATCHY FOG...BUT WILL TRIM BACK THE
WESTERN EDGE OF THIS (ROUGHLY DIGHTON TO DODGE CITY TO COLDWATER
LINE) PER GUIDANCE FROM THE LATEST RUNS OF THE HRRR MODEL AS WELL AS
TRENDS ON SATELLITE. THE FOG AND STRATUS PROBABLY WONT EVEN MAKE IT
THAT FAR WEST. THE REST OF THE FORECAST FOR TODAY AND TONIGHT IS
FAIRLY STRAIGHT FORWARD UNDER THE MID LEVEL RIDGE AXIS. HIGHS TODAY
WILL BE UPPER 80S TO NEAR 90 AS DIRECT INSOLATION WILL PREVAIL.
SURFACE WINDS WILL BEGIN TO RESPOND TO LOWERING PRESSURE OUT WEST
OVER THE HIGHER TERRAIN...BUT MAINLY ACROSS THE WESTERN COUNTIES
CLOSE TO THE COLORADO BORDER (WEST OF HIGHWAY 83). TONIGHT...ANOTHER
CLEAR AND (NEAR) CALM NIGHT IS EXPECTED WITH LOWS IN THE LOWER TO
MID 60S. A PATCHY AREA OF LIGHT FOG WILL PROBABLY DEVELOP AGAIN IN
LOW LYING AREAS GIVEN IDEAL RADIATIONAL COOLING AND MOIST
GROUND...BUT THE COVERAGE OF ANY FOG DOES NOT REALLY WARRANT
INCLUSION IN GRIDS AT THIS TIME.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 123 AM CDT SUN AUG 26 2012
A RELATIVELY DRY PERIOD IS EXPECTED ACROSS WESTERN KANSAS AS MEDIUM
RANGE MODELS CONTINUE TO INDICATE A LARGE UPPER LEVEL RIDGE OF HIGH
PRESSURE PREVAILING ACROSS THE COLORADO ROCKIES AND THE WESTERN HIGH
PLAINS THROUGH AT LEAST MID WEEK. A GRADUAL WARMING TREND IS LIKELY
THROUGH AT LEAST WEDNESDAY AS A LEE SIDE TROUGH OF LOW PRESSURE
HELPS INFLUENCE A LOW LEVEL SOUTHERLY FLOW ACROSS WESTERN KANSAS
THROUGH MUCH OF THE PERIOD. FOR MONDAY, THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES RANGING FROM JUST ABOVE 20C ACROSS CENTRAL KANSAS
TO JUST ABOVE 25C NEAR THE COLORADO BORDER. ALONG WITH PLENTY OF
SUNSHINE, LOOK FOR HIGHS NEAR TO JUST ABOVE 90F MONDAY AFTERNOON.
THE WARMING TREND WILL CONTINUE WITH HIGHS EXPECTED UP INTO THE LOW
TO MID 90S(F) THROUGH AT LEAST THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 610 AM CDT SUN AUG 26 2012
LOW LEVEL STRATUS AND AREAS OF PATCHY FOG ACROSS CENTRAL KANSAS
WILL CONTINUE TO DRIFT WESTWARD THROUGH MID MORNING...MAINLY
AFFECTING KHYS WITH MVFR CIGS/VSBYS. A BRIEF PERIOD OF IFR CIGS
CANNOT BE RULED OUT AT KHYS BEFORE VFR CONDITIONS RETURN LATE THIS
MORNING. MVFR VSBYS ARE LIKELY TO CONTINUE AT KDDC AND KGCK
THROUGH AT LEAST 14Z WITH VFR CONDITIONS RAPIDLY RETURNING
SHORTLY THEREAFTER. VFR CONDITIONS WILL THEN PREVAIL AT ALL TAF
SITES THE REMAINDER OF THE DAY AND EVENING. AS FOR WINDS, SURFACE
HIGH PRESSURE IN THE NORTHERN PLAINS WILL SINK SOUTHWARD INTO
KANSAS TODAY. THIS WILL RESULT IN LIGHT AND VARIABLE WINDS THROUGH
MUCH OF THE DAY AND EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 88 64 91 62 / 0 10 0 0
GCK 90 61 92 61 / 0 10 0 0
EHA 90 63 92 61 / 0 10 0 0
LBL 88 64 92 62 / 0 10 0 0
HYS 88 63 91 61 / 0 10 0 0
P28 87 67 92 64 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS GOODLAND KS
509 AM MDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 500 AM MDT SUN AUG 26 2012
HAVE ISSUED A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW
COUNTIES THROUGH 9 AM MDT (10 AM CDT). VISIBILITIES AT KMCK 1/4
MILE OR LESS. LATEST RUC HAS A GOOD HANDLE ON THIS AND WITH LIGHT
WINDS EXPECT THE FOG TO DRIFT INTO HITCHCOCK COUNTY WITHIN THE
NEXT FEW HOURS. WILL HAVE TO WATCH THE ATWOOD AND OBERLIN AREAS
FOR POSSIBLE HEADLINE GIVEN SIMILAR CONDITIONS. WILL WAIT FOR CO-
OP REPORTS AND DAYLIGHT TO VIEW WEB CAMS BEFORE MAKING AND FURTHER
ADJUSTMENTS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 215 AM MDT SUN AUG 26 2012
TODAY-TONIGHT...AT 08Z THIS MORNING STRATUS AND FOG WERE JUST
EAST OF THE FORECAST AREA BUT MOVING TOWARD THE WEST AT 15 MPH.
THIS WOULD PUT IT AS FAR WEST AS MCCOOK TO OBERLIN AND WAKEENEY BY
12Z THIS MORNING. VISIBILITIES ARE IN THE 1/4 MILE RANGE ARE
COMMON PER OBSERVATIONS. WILL CONTINUE TO WATCH JUST HOW FAR WEST
IT GETS AND SHOULD IT REACH THE FORECAST AREA A DENSE FOG ADVISORY
WILL BE NEEDED.
OTHERWISE OTHER CONCERN IS ON TIMING OF A FEW THUNDERSTORMS WHICH
SHOULD REACH THE WESTERN 1/4 OF THE AREA (MAINLY FAR EASTERN
COLORADO) BY LATE IN THE AFTERNOON. THESE APPEAR TO BE DIURNALLY
DRIVEN WITHIN AN AXIS OF 700-300 MOISTURE AND AM THINKING THAT ANY
STORMS THAT DO DEVELOP WILL DISSIPATE SHORTLY AFTER SUNSET. HIGH
TEMPERATURES TODAY UPPER 80S TO LOW 90S. LOWS TONIGHT UPPER 50S TO
LOW 60S.
MONDAY-TUESDAY NIGHT...UPPER RIDGE TO BUILD OVER COLORADO THROUGH
THE PERIOD. BREEZY SOUTH TO SOUTHEAST WINDS EXPECTED DURING THE
DAY WITH HIGH TEMPERATURES IN THE LOW TO MID 90S BOTH DAYS. LOWS
UPPER 50S TO LOW 60S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 215 AM MDT SUN AUG 26 2012
THE H5 RIDGE THAT WILL DEVELOP EARLIER IN THE PERIOD IS EXPECTED
TO PERSIST UNTIL NEAR THE MIDDLE OF THE EXTENDED RANGE PERIOD WHEN
A WEAK FRONTAL ZONE MAY AFFECT THE TRI-STATE REGION. CONDITIONS
WILL BE HOT AND DRY WEDNESDAY AND THURSDAY AS THE H5 RIDGE
GRADUALLY MOVES EAST AS A TROUGH ENTERS THE PACIFIC NORTHWEST.
LATE THURSDAY A FRONTAL BOUNDARY BEGINS TO FORM THROUGH THE UPPER
HIGH PLAINS AND MOVE EAST DURING THE WEEKEND. FROM LOOKING AT THE
PAST FEW DAYS OF MODEL RUNS THIS FEATURE HAS CONSISTENT...BUT ITS
SPATIAL...TEMPORAL ...AND STRENGTH QUALITIES HAVE BEEN ALL OVER
THE MAP. THIS IS LIKELY DUE TO BOTH THE MODEL HANDLING OF THE
TROUGH DIGGING IN TO THE PACIFIC NORTHWEST AND TROPICAL STORM
ISAAC. FOR NOW HAVE INCLUDED MINIMAL SLIGHT CHANCE POPS ON FRIDAY
EVENING FOR THE NORTHWESTERN PART OF THE CWA...WITH DRY CONDITIONS
FORECAST FOR THE REST OF THE PERIOD. TEMPERATURES OVER THE PERIOD
WILL BE WARMER THAN AVERAGE...WITH HIGHS IN THE MID TO LOWER 90S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 503 AM MDT SUN AUG 26 2012
DENSE FOG OF 1/4SM VISIBILITY WILL PERSIST THROUGH THE FIRST FEW
HOURS OF THE TAF AS PART OF A LARGE AREA OF DENSE FOG IN SOUTHERN
NEBRASKA AND NORTH CENTRAL KANSAS...WITH IFR CONDITIONS LASTING
UNTIL ABOUT 15Z. FOLLOWING THIS CONDITIONS WILL RAPIDLY IMPROVE TO
IFR CONDITIONS THROUGH THE REST OF THE PERIOD WITH CLEAR SKIES AND
A LIGHT SOUTH-SOUTHEAST WIND.
FOR GLD SOME PATCHY FOG IS EXPECTED THIS MORNING BUT IFR
CONDITIONS ARE NOT EXPECTED TO DEVELOP. ANY FOG THAT DOES DEVELOP WILL
QUICKLY DISSIPATE BY 14Z...AND CONDITIONS WILL REMAIN VFR FOR THE
REST OF THE PERIOD. CLEAR SKIES AND SOUTH-SOUTHEAST WINDS GUSTING
TO 20KTS WILL BE PREVAILING THIS AFTERNOON...WITH WEAKER WINDS
DURING THE OVERNIGHT HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ080-081.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...99/JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
503 AM MDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 500 AM MDT SUN AUG 26 2012
HAVE ISSUED A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW
COUNTIES THROUGH 9 AM MDT (10 AM CDT). VISIBILITIES AT KMCK 1/4
MILE OR LESS. LATEST RUC HAS A GOOD HANDLE ON THIS AND WITH LIGHT
WINDS EXPECT THE FOG TO DRIFT INTO HITCHCOCK COUNTY WITHIN THE
NEXT FEW HOURS. WILL HAVE TO WATCH THE ATWOOD AND OBERLIN AREAS
FOR POSSIBLE HEADLINE GIVEN SIMILAR CONDITIONS. WILL WAIT FOR CO-
OP REPORTS AND DAYLIGHT TO VIEW WEB CAMS BEFORE MAKING AND FURTHER
ADJUSTMENTS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 215 AM MDT SUN AUG 26 2012
TODAY-TONIGHT...AT 08Z THIS MORNING STRATUS AND FOG WERE JUST
EAST OF THE FORECAST AREA BUT MOVING TOWARD THE WEST AT 15 MPH.
THIS WOULD PUT IT AS FAR WEST AS MCCOOK TO OBERLIN AND WAKEENEY BY
12Z THIS MORNING. VISIBILITIES ARE IN THE 1/4 MILE RANGE ARE
COMMON PER OBSERVATIONS. WILL CONTINUE TO WATCH JUST HOW FAR WEST
IT GETS AND SHOULD IT REACH THE FORECAST AREA A DENSE FOG ADVISORY
WILL BE NEEDED.
OTHERWISE OTHER CONCERN IS ON TIMING OF A FEW THUNDERSTORMS WHICH
SHOULD REACH THE WESTERN 1/4 OF THE AREA (MAINLY FAR EASTERN
COLORADO) BY LATE IN THE AFTERNOON. THESE APPEAR TO BE DIURNALLY
DRIVEN WITHIN AN AXIS OF 700-300 MOISTURE AND AM THINKING THAT ANY
STORMS THAT DO DEVELOP WILL DISSIPATE SHORTLY AFTER SUNSET. HIGH
TEMPERATURES TODAY UPPER 80S TO LOW 90S. LOWS TONIGHT UPPER 50S TO
LOW 60S.
MONDAY-TUESDAY NIGHT...UPPER RIDGE TO BUILD OVER COLORADO THROUGH
THE PERIOD. BREEZY SOUTH TO SOUTHEAST WINDS EXPECTED DURING THE
DAY WITH HIGH TEMPERATURES IN THE LOW TO MID 90S BOTH DAYS. LOWS
UPPER 50S TO LOW 60S.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 215 AM MDT SUN AUG 26 2012
THE H5 RIDGE THAT WILL DEVELOP EARLIER IN THE PERIOD IS EXPECTED
TO PERSIST UNTIL NEAR THE MIDDLE OF THE EXTENDED RANGE PERIOD WHEN
A WEAK FRONTAL ZONE MAY AFFECT THE TRI-STATE REGION. CONDITIONS
WILL BE HOT AND DRY WEDNESDAY AND THURSDAY AS THE H5 RIDGE
GRADUALLY MOVES EAST AS A TROUGH ENTERS THE PACIFIC NORTHWEST.
LATE THURSDAY A FRONTAL BOUNDARY BEGINS TO FORM THROUGH THE UPPER
HIGH PLAINS AND MOVE EAST DURING THE WEEKEND. FROM LOOKING AT THE
PAST FEW DAYS OF MODEL RUNS THIS FEATURE HAS CONSISTENT...BUT ITS
SPATIAL...TEMPORAL ...AND STRENGTH QUALITIES HAVE BEEN ALL OVER
THE MAP. THIS IS LIKELY DUE TO BOTH THE MODEL HANDLING OF THE
TROUGH DIGGING IN TO THE PACIFIC NORTHWEST AND TROPICAL STORM
ISAAC. FOR NOW HAVE INCLUDED MINIMAL SLIGHT CHANCE POPS ON FRIDAY
EVENING FOR THE NORTHWESTERN PART OF THE CWA...WITH DRY CONDITIONS
FORECAST FOR THE REST OF THE PERIOD. TEMPERATURES OVER THE PERIOD
WILL BE WARMER THAN AVERAGE...WITH HIGHS IN THE MID TO LOWER 90S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1132 PM MDT SAT AUG 25 2012
VFR TO LIFR CONDITIONS ARE FORECAST FOR THE 6Z TAFS. LATEST REPORT
FROM KMCK HAS VISIBILITIES DROPPING TO 7 MILES WITH WINDS AROUND 5
KTS. WITH VIS DROPPING THIS QUICKLY DESPITE THE LIGHT BREEZE HAVE
SPED UP THE TIMING OF VISIBILITIES DROPPING. THE OVERALL TIMING
MAY BE OFF AN HOUR EITHER DIRECTION BUT GENERALLY AM THINKING
VISIBILITIES WILL BE LOWEST CLOSER TO 12Z. VISIBILITY COULD DROP AS
LOW AS A QUARTER MILE FOR A BRIEF TIME...BUT DO NOT HAVE ENOUGH
CONFIDENCE THE WIND WILL STAY LIGHT ENOUGH FOR LONG ENOUGH TO
WARRANT A MENTION IN THE TAF. AFTER 12Z THE FOG SHOULD QUICKLY
BURN OFF.
DID INCLUDE A BRIEF MVFR WINDOW FOR KGLD SINCE MOS GUIDANCE
INDICATES VISIBILITIES COULD DIP BELOW 6 MILES FOR A SHORT TIME.
OTHERWISE FOG WILL QUICKLY DISSIPATE AFTER 12Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ080-081.
&&
$$
UPDATE...99
SHORT TERM...99
LONG TERM...JJM
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
337 AM CDT SUN AUG 26 2012
...UPDATED SYNOPSIS AND SHORT TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 336 AM CDT SUN AUG 26 2012
ON THE SYNOPTIC SCALE...THE MID LEVEL TROUGH THAT BROUGHT ALL THE
RECENT RAINS EXTENDED FROM CENTRAL IOWA TO EASTERN KANSAS TO
NORTHWEST TEXAS EARLY THIS MORNING. SEVERAL THUNDERSTORM CLUSTERS
THRIVED THROUGH THE NIGHT ALONG THE TROUGH AXIS...PARTICULARLY FROM
NORTHERN OKLAHOMA INTO SOUTHEASTERN KANSAS. WATER VAPOR LOOP AS OF
08Z SHOWED SIGNIFICANT MID LEVEL DRYING IN THE WAKE OF THIS TROUGH
AXIS WITH SHORT WAVE RIDGING BUILDING IN ITS WAKE. ALSO IN ITS WAKE
IS A RATHER NON-EXISTENT MEAN SEA LEVEL PRESSURE FIELD WITH THE MSLP
ANALYSIS RATHER ISOBARIC IN NATURE AS MSLP WAS 1013 OR 1014MB FROM
WESTERN KANSAS INTO NEBRASKA, WESTERN IOWA, AND THE DAKOTAS. THIS
RESULTED IN WIDESPREAD CALM OR NEARLY CALM WINDS WITH RESIDUAL
MOISTURE REMNANT FROM BOTH THE RECENT RAINS AND INFLUX OF GULF OF
MEXICO MOISTURE INTO THE AREA AHEAD OF THE TROUGH WHICH WAS NOT
PUSHED OUT OF HERE WITH NO COLD FRONT. A BAROCLINIC WAVE WHICH DID
PASS ACROSS THE SOUTHERN CANADIAN PRAIRIES DID PUSH A COLD FRONT
SOUTH YESTERDAY BUT STALLED OUT, WEAKENED, AND ULTIMATELY DIED OVER
THE SANDHILLS OF NEBRASKA. AS OF 0815Z...THE 11-3.9 MICRON
SATELLITE LOOP CONFIRMED THE DEVELOPMENT OF LOW STRATUS AND FOG
ACROSS NORTH-CENTRAL KANSAS WHICH WAS PUSHING TOWARD THE HAYS AREA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 336 AM CDT SUN AUG 26 2012
IN THE VERY SHORT TERM...LOW STRATUS AND FOG WILL BE THE MAIN ISSUE
ON THE AVIATION SIDE OF THINGS. THE GRIDS ALREADY REFLECT
DEVELOPMENT OF CLOUDS AND PATCHY FOG...BUT WILL TRIM BACK THE
WESTERN EDGE OF THIS (ROUGHLY DIGHTON TO DODGE CITY TO COLDWATER
LINE) PER GUIDANCE FROM THE LATEST RUNS OF THE HRRR MODEL AS WELL AS
TRENDS ON SATELLITE. THE FOG AND STRATUS PROBABLY WONT EVEN MAKE IT
THAT FAR WEST. THE REST OF THE FORECAST FOR TODAY AND TONIGHT IS
FAIRLY STRAIGHT FORWARD UNDER THE MID LEVEL RIDGE AXIS. HIGHS TODAY
WILL BE UPPER 80S TO NEAR 90 AS DIRECT INSOLATION WILL PREVAIL.
SURFACE WINDS WILL BEGIN TO RESPOND TO LOWERING PRESSURE OUT WEST
OVER THE HIGHER TERRAIN...BUT MAINLY ACROSS THE WESTERN COUNTIES
CLOSE TO THE COLORADO BORDER (WEST OF HIGHWAY 83). TONIGHT...ANOTHER
CLEAR AND (NEAR) CALM NIGHT IS EXPECTED WITH LOWS IN THE LOWER TO
MID 60S. A PATCHY AREA OF LIGHT FOG WILL PROBABLY DEVELOP AGAIN IN
LOW LYING AREAS GIVEN IDEAL RADIATIONAL COOLING AND MOIST
GROUND...BUT THE COVERAGE OF ANY FOG DOES NOT REALLY WARRANT
INCLUSION IN GRIDS AT THIS TIME.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 123 AM CDT SUN AUG 26 2012
A RELATIVELY DRY PERIOD IS EXPECTED ACROSS WESTERN KANSAS AS MEDIUM
RANGE MODELS CONTINUE TO INDICATE A LARGE UPPER LEVEL RIDGE OF HIGH
PRESSURE PREVAILING ACROSS THE COLORADO ROCKIES AND THE WESTERN HIGH
PLAINS THROUGH AT LEAST MID WEEK. A GRADUAL WARMING TREND IS LIKELY
THROUGH AT LEAST WEDNESDAY AS A LEE SIDE TROUGH OF LOW PRESSURE
HELPS INFLUENCE A LOW LEVEL SOUTHERLY FLOW ACROSS WESTERN KANSAS
THROUGH MUCH OF THE PERIOD. FOR MONDAY, THE NAM, GFS, AND ECMWF SHOW
H85 TEMPERATURES RANGING FROM JUST ABOVE 20C ACROSS CENTRAL KANSAS
TO JUST ABOVE 25C NEAR THE COLORADO BORDER. ALONG WITH PLENTY OF
SUNSHINE, LOOK FOR HIGHS NEAR TO JUST ABOVE 90F MONDAY AFTERNOON.
THE WARMING TREND WILL CONTINUE WITH HIGHS EXPECTED UP INTO THE LOW
TO MID 90S(F) THROUGH AT LEAST THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 106 AM CDT SUN AUG 26 2012
THE MAIN DIFFICULTY IN THE AVIATION FORECAST IS HOW MUCH, IF AT ALL,
GROUND CONDITIONS WILL DETERIORATE IN RADIATION FOG FORMATION. VERY
LIGHT, IF NOT CALM WINDS WILL REMAIN THROUGH THE NIGHT, AND BY
DAYBREAK VISIBILITY SHOULD FALL IN LIGHT FOG FORMATION AT DDC AND
HYS. WILL GO WITH A TEMPO GROUP FOR THE 11-13Z TIME FRAME BRINGING
VISIBILITY DOWN TO 1 MILE. I DO NOT HAVE THE CONFIDENCE TO GO ANY
LOWER THAN A MILE...BUT SOME PATCHY DENSE FOG MAY DEVELOP NEAR OR
OVER EITHER DDC AND HYS FOR A BRIEF TIME RIGHT AT DAYBREAK.
OTHERWISE...VFR CONDITIONS WILL RESUME SHORTLY AFTER SUNRISE WITH A
8-10 KNOT WIND FROM THE NORTHEAST EXPECTED THE REMAINDER OF THE DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 88 64 91 62 / 0 10 0 0
GCK 90 61 92 61 / 0 10 0 0
EHA 90 63 92 61 / 0 10 0 0
LBL 88 64 92 62 / 0 10 0 0
HYS 88 63 91 61 / 0 10 0 0
P28 87 67 92 64 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1014 PM MDT SAT AUG 25 2012
.UPDATE...
ISSUED AT 956 PM MDT SAT AUG 25 2012
OVERALL FORECAST LOOKED TO BE IN GOOD SHAPE...BUT DECIDED TO
EXTEND THE COVERAGE OF THE FOG FURTHER WEST TO THE COLORADO BORDER BASED
ON THE TRENDS IN MOS GUIDANCE. AM THINKING THE WESTERN EXTENT OF
THE FOG WILL BE MOSTLY CONFINED TO LOW-LYING AREAS DUE TO THE
LOWER RH VALUES IN THE BOUNDARY LAYER. FOR THE HILL CITY TO EAST
OF MCCOOK ADDED A MENTION OF WIDE SPREAD FOG SINCE ALMOST ALL
GUIDANCE PLACES FOG OVER OR JUST EAST OF THAT AREA. AGREE WITH
THE PREVIOUS SHIFT THE LOWER VISIBILITIES WILL BE OVER THE EASTERN
PART OF THE AREA...MAINLY ALONG AND EAST OF A RUSSELL SPRINGS TO
MCCOOK LINE. WITH MOST GUIDANCE CURRENTLY PLACING VISIBILITIES OF
TWO MILES FOR THESE LOCATIONS...WOULD NOT BE SURPRISED IF SOME
LOCATIONS HAVE VISIBILITIES DROP TO A HALF MILE...ESPECIALLY IN
LOW- LYING AREAS. THE FOG SHOULD BURN OFF BY MID MORNING.
DO NOT PLAN ON ISSUING A DENSE FOG ADVISORY SINCE POINT SOUNDINGS
STILL SHOW A VERY SHALLOW SATURATED LAYER AT THE SURFACE. WOULD
PREFER TO SEE A DEEPER SATURATED LAYER BEFORE CONTEMPLATING AN
ADVISORY. IN ADDITION THE 0Z MOS GUIDANCE CAME IN WITH SLIGHTLY
BETTER VISIBILITIES WHICH FURTHER DECREASES CONFIDENCE IN THE NEED
FOR AN ADVISORY. MID SHIFT WILL MONITOR THROUGH THE NIGHT TO SEE
IF VISIBILITIES DROP MORE THAN FORECAST.
&&
.SHORT TERM...(THIS EVENING)
ISSUED AT 108 PM MDT SAT AUG 25 2012
RADAR IS SHOWING A DECREASING TREND WITH THE LIGHT PRECIPITATION.
THIS IS A RESULT OF THE MID LEVEL LOW MOVING OFF TO THE EAST.
STRONG MID LEVEL SUBSIDENCE AND DRYING MOVING INTO THE NORTHWEST
PORTION ALREADY. SO HAVE TONIGHT DRY. LIGHT UPSLOPE TO LIGHT AND
VARIABLE WINDS WILL BE IN PLACE BY LATER TONIGHT. DRIER AIR FROM
THE SURFACE THROUGH MID LEVELS WILL MOVE INTO THE WESTERN PORTION
WITH INCREASING LOW LEVEL MOISTURE IN THE EASTERN PORTION. SO HAVE
INCREASED CLOUD COVER IN THE EAST AND HAVE EXPANDED THE AREA OF
FOG FURTHER WEST AND INCREASED COVERAGE TO AREAS IN THE FAR EAST.
COOLER MINS WILL BE IN THE WEST WITH THE DRIER AIR.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 225 PM MDT SAT AUG 25 2012
SUNDAY-TUESDAY...NEAR TERM MODELS IN REASONABLE AGREEMENT THAT 594
DM RIDGE WILL BEGIN TO BUILD OVER THE AREA THROUGH THE
PERIOD...GENERALLY BRINGING AN END TO THE MORE WIDESPREAD
PRECIPITATION THREAT OF THE PAST FEW DAYS. INITIAL CONCERN WILL BE
HOW QUICKLY H5 TROUGH MOVES EAST OUT OF THE AREA AND WHETHER OR IT
WILL CONTINUE TO LINGER ACROSS THE EASTERN CWA. LATEST OPERATIONAL
GUIDANCE AS WELL AS SREF DATA SUPPORT TROUGH BEING WELL TO THE EAST
OF THE CWA BY SUNDAY MORNING WITH LARGE SCALE SUBSIDENCE BRINGING AN
END TO PRECIPITATION THREAT BY SUNRISE. STRONGEST SUBSIDENCE WILL
REMAIN OVER EASTERN CWA AS SHORT WAVE TROUGH DEPARTS THE AREA WITH
FAIRLY NEUTRAL LARGE SCALE FORCING ACROSS THE WEST DESPITE SLOWLY
AMPLIFYING TROUGH. WITH NO LARGE CHANGE IN AIR MASS
EXPECTED...ATMOSPHERE WILL DESTABILIZE AS EASTERLY FLOW BRINGS 50+
TDS INTO EASTERN COLORADO ALONG SFC TROUGH. SOUNDINGS AND MIXED
LAYER CINH FIELDS SUGGEST THERE WILL BE ROUGH 50 J/KG OF CINH ACROSS
THE AREA AND WHILE PERSISTENT CONVERGENCE MAY BE ENOUGH TO INITIATE A
STORM OR TWO...CONFIDENCE IN THIS SCENARIO IS LOW. GIVEN WEAK WINDS
ALOFT STORMS WOULD STRUGGLE TO MOVE OFF ON THE INITIATION AREA FOR
MOST OF THE AFTERNOON AND LATE EVENING. OTHERWISE WITH TEMPERATURES
GRADUALLY WARMING ALOFT AND MOISTURE PROFILES DIMINISHING THROUGH
TUESDAY THINK PRECIPITATIONS CHANCES WILL BE VERY LOW UNDER LARGE
SCALE RIDGE. TEMPERATURES WILL GRADUALLY WARM THROUGH THE
PERIOD...ALTHOUGH WITH SFC TROUGH TO THE NORTHWEST AND PERSISTENT
SFC RIDGE ACROSS EASTERN CWA HAVE A FEW CONCERNS THAT COOLER AIR MASS
MAY LINGER IN THE EASTERN CWA SO HAVE NOT RAISED TEMPS ALL THAT MUCH
IN THIS AREA.
IN THE EXTENDED (TUES NIGHT-SATURDAY)...MEDIUM RANGE MODELS IN
GENERAL AGREEMENT WITH LARGE SCALE PATTERN AROUND THE CWA...BUT
SIGNIFICANT DIFFERENCES WITH THE HANDLING OF ISAAC WHICH DOES
INFLUENCE THE OVERALL PATTERN...WHICH INCREASES THE UNCERTAINTY OF
THE OVERALL FORECAST. WHILE GFS/GEM AND GEFS MEAN ARE IN GOOD
AGREEMENT...SEEING THE 12Z ECWMF DATA MAKES ME THINK THAT THERE
REMAINS A GREAT DEAL OF UNCERTAINTY WITH RESPECT TO OVERALL PATTERN
FOR THE COMING WEEK AND THINK CURRENT CONSENSUS FORECAST FOR THE
MOST PART IS REASONABLE FOR THE PERIOD. IN GENERAL...EXPECT TEMPS TO
WARM BACK INTO THE LOWER TO MID 90S UNDER LARGE SCALE RIDGE. WEAK
FRONTAL ZONE MAY IMPACT NORTHWEST CWA BRINGING A SMALL CHANCE FOR
PRECIPITATION BUT LATEST DATA DOES NOT SUPPORT MORE THAN A 10-20%
CHANCE THROUGH A MAJORITY OF THE PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 456 PM MDT SAT AUG 25 2012
VFR TO IFR CONDITIONS ARE FORECAST FOR THE 0Z TAFS. LATEST
MODEL/MOS GUIDANCE IS SPLIT ON WHETHER FOG/STRATUS WILL DEVELOP AT
KMCK AND HOW FAR WEST IT WILL EXTEND. LATEST HRRR/NAM/SREF KEEP
THE FOG EAST OF KMCK WHILE GFS/RUC/MOS PLACE THE FOG AS FAR WEST
AS KGLD. WITH A SUCH A DISAGREEMENT BETWEEN THE VARIOUS GUIDANCE
WILL NOT ALTER THE TAFS TOO MUCH FROM THE 18Z ISSUANCE. HOWEVER
POINT SOUNDINGS FROM THE RUC ARE NOT TOO SUPPORTIVE OF LOW
VISIBILITIES AT KMCK...WITH A DRY LAYER SANDWICHED BETWEEN
SATURATION AT THE SURFACE AND ROUGHLY 1500 FT AGL. WILL WAIT UNTIL
THE 6Z TAF ISSUANCE BEFORE MAKING TOO MANY CHANGES. OTHERWISE
CONDITIONS SHOULD QUICKLY IMPROVE AFTER 12Z WITH LIGHT WINDS
THROUGH SUNDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...JRM
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1240 PM CDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 1240 PM CDT SUN AUG 26 2012
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 18Z TAF ISSUANCE.
UPDATE ISSUED AT 855 AM CDT SUN AUG 26 2012
JUST UPDATED THE KPAH TAF AND THE PUBLIC FORECAST TO ACCOUNT FOR
SCATTERED SHOWERS ONGOING OVER THE PURCHASE AREA EARLY THIS
MORNING. THE HRRR...06Z NAM AND 00Z WRF RUNS ALL INDICATE AN
UPTICK IN COVERAGE AS THIS ZONE OF SHOWERS PUSHES EASTWARD ACROSS
THE AREA THIS MORNING. TRIED TO INDICATE THIS IN THE POP GRIDS
THROUGH 18Z.
THEY ALSO INDICATE A TREND TOWARD DEVELOPMENT IN THE WEST LATER
THIS AFTERNOON...ESPECIALLY IF THAT AREA CAN WARM UP ANY. TRIED TO
USED THE HRRR AND NAM 2-M TEMPERATURE FORECASTS TO SHOW A
REALISTIC TEMPERATURE TREND THROUGH THE DAY. GIVEN THE AMOUNT OF
CLOUDS OVER THE AREA...AND A FEW CONSPICUOUSLY CLEAR
AREAS...TEMPERATURE TRENDS WILL BE A BEAR TO KEEP UP WITH TODAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 313 AM CDT SUN AUG 26 2012
BIGGEST FORECAST CHALLENGE WILL BE WITH RAIN/THUNDER CHANCES...
MAINLY TODAY....AND ESP MON. MID LEVEL TROF AND ASSOCIATED WEAK
SFC SHOULD EVENTUALLY MOVE EAST FROM THE PLAINS AND START TO BRING
SHOWER/THUNDER CHCS TO AREAS ALONG AND WEST OF THE MS RIVER
TODAY/TONIGHT. HOWEVER...IT STILL APPEARS THE BEST CHANCE OF A
MORE WIDESPREAD PRECIP COVERAGE WILL COME ON MONDAY AS THE SFC
FRONT DRIFTS SLOWLY THROUGH THE FORECAST AREA. NOT LOOKING AT A
MAJOR RAIN SYSTEM AT THIS TIME...AND EXTENSIVE CLOUDS SUN NIGHT/MON
WILL LIKELY PRECLUDE ANY SEVERE STORM RISK. RAIN CHANCES WILL
DIMINISH FROM WEST TO EAST MONDAY NIGHT AS THE SFC FRONT EASES
SOUTHEAST AND H70 TROF SHIFTS EAST. THIS SHOULD CREATE A RATHER
DRY TUESDAY. WILL STICK CLOSE TO ONGOING TEMPS....SLIGHTLY ABOVE
NORMAL FOR THIS TIME OF YEAR.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 340 AM CDT SAT AUG 25 2012
THE MAIN CONCERN CONTINUES TO BE THE PATH OF TS ISAAC.
THE LATEST MODELS RUNS CONTINUE TO BE IN COMPLETE DISARRAY. THE 12Z
SATURDAY ECMWF FOR THE FIRST TIME TAKES THE EASTERN MOST PATH ALONG
THE EASTERN COAST. PREVIOUS 3 DAYS IT HAS RANGED FROM WESTERN MO TO
WESTERN KY SO THIS IS THE LARGEST FLIP FLOP FOR THE OPERATIONAL
ECMWF. THE LATEST 00Z SUN ECMWF ACTUALLY BRINGS THE CENTER OF THE
REMNANTS OF ISAAC OVER THE PENNYRILE AREA OF W KY. THE 00Z SUN GFS
RUN ACTUALLY BRINGS THE CENTER OF ISAAC OVER SGF. FOR THE FIRST TIME
THIS WEEK THE GFS HAS THE WESTERN TRACK AND THE ECMWF HAS THE
EASTERN TRACK. THE ENSEMBLES ARE MUCH HELP EITHER. MOST OF THE
MODELS PERFORM WELL UNTIL ISSAC MAKES LANDFALL AND THEN ITS A CRAP
SHOOT AS FAR AS THE MODELS GO. THIS UNCERTAINTY WILL WREAK HAVOC ON
TEMP FCST AS WELL. AS PREVIOUS DISC STATED IT COULD BE 70S WITH
ISSAC OVER THE AREA OR MID 90S IF IT MISSES US. SO AGAIN DRAMATIC
CHANGES SHOULD BE ANTICIPATED WITH THE EXTENDED SHOULD A REASONABLE
SOLUTION REVEAL ITSELF IN THE NEAR FUTURE. FOR NOW WILL LEAN TOWARD
THE NHC FCST AS DID HPC BUT CONFIDENCE IS EXTREMELY LOW.
FOR THE AFOREMENTIONED REASONS LITTLE CHANGE WAS MADE TO TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM CDT SUN AUG 26 2012
WILL CONTINUE TO SEE SOME AMOUNT OF CU AND MID CLOUD OVER THE
REGION THROUGH THE PERIOD. THE MVFR CEILING AT KCGI AS OF 17Z
SHOULD NOT LAST LONG BEFORE SCATTERING OUT OR LIFTING ABOVE 3KFT.
SCATTERED SHOWERS MAY FLIRT WITH KOWB FOR THE FIRST FEW HOURS OF
THE FORECAST. DECIDED TO JUST GO WITH A VCSH...AND WILL ADD TS
IF/WHEN IT BECOMES NECESSARY. SOUTH TO SOUTHWEST WINDS MAY GUST
INTO THE TEENS THROUGHOUT THE AREA THIS AFTERNOON. GUIDANCE IS
NOT ALL THAT EXCITED ABOUT CONVECTIVE DEVELOPMENT ELSEWHERE THIS
AFTERNOON...SO WILL HAVE TO AMEND TO HANDLE ANY LATER DEVELOPMENT.
THE COLD FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO
THE REGION LATE TONIGHT AND MONDAY MORNING. FOR NOW WILL JUST
MENTION A VCSH AT KCGI GENERALLY AFTER SUNRISE...AND KEEP THE
REMAINDER OF THE AREA DRY. A LIGHT SOUTH WIND TONIGHT WILL VEER TO
WEST OR SOUTHWEST IN THE MORNING. MAY FLIRT WITH SOME MVFR
CEILINGS IN THE MORNING...BUT CONFIDENCE IS NOT HIGH....SO WILL
JUST MENTION A SCATTERED LAYER NEAR 3KFT FOR NOW.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MEFFERT
LONG TERM....KH
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
859 AM CDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 855 AM CDT SUN AUG 26 2012
JUST UPDATED THE KPAH TAF AND THE PUBLIC FORECAST TO ACCOUNT FOR
SCATTERED SHOWERS ONGOING OVER THE PURCHASE AREA EARLY THIS
MORNING. THE HRRR...06Z NAM AND 00Z WRF RUNS ALL INDICATE AN
UPTICK IN COVERAGE AS THIS ZONE OF SHOWERS PUSHES EASTWARD ACROSS
THE AREA THIS MORNING. TRIED TO INDICATE THIS IN THE POP GRIDS
THROUGH 18Z.
THEY ALSO INDICATE A TREND TOWARD DEVELOPMENT IN THE WEST LATER
THIS AFTERNOON...ESPECIALLY IF THAT AREA CAN WARM UP ANY. TRIED TO
USED THE HRRR AND NAM 2-M TEMPERATURE FORECASTS TO SHOW A
REALISTIC TEMPERATURE TREND THROUGH THE DAY. GIVEN THE AMOUNT OF
CLOUDS OVER THE AREA...AND A FEW CONSPICUOUSLY CLEAR
AREAS...TEMPERATURE TRENDS WILL BE A BEAR TO KEEP UP WITH TODAY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 313 AM CDT SUN AUG 26 2012
BIGGEST FORECAST CHALLENGE WILL BE WITH RAIN/THUNDER CHANCES...
MAINLY TODAY....AND ESP MON. MID LEVEL TROF AND ASSOCIATED WEAK
SFC SHOULD EVENTUALLY MOVE EAST FROM THE PLAINS AND START TO BRING
SHOWER/THUNDER CHCS TO AREAS ALONG AND WEST OF THE MS RIVER
TODAY/TONIGHT. HOWEVER...IT STILL APPEARS THE BEST CHANCE OF A
MORE WIDESPREAD PRECIP COVERAGE WILL COME ON MONDAY AS THE SFC
FRONT DRIFTS SLOWLY THROUGH THE FORECAST AREA. NOT LOOKING AT A
MAJOR RAIN SYSTEM AT THIS TIME...AND EXTENSIVE CLOUDS SUN NIGHT/MON
WILL LIKELY PRECLUDE ANY SEVERE STORM RISK. RAIN CHANCES WILL
DIMINISH FROM WEST TO EAST MONDAY NIGHT AS THE SFC FRONT EASES
SOUTHEAST AND H70 TROF SHIFTS EAST. THIS SHOULD CREATE A RATHER
DRY TUESDAY. WILL STICK CLOSE TO ONGOING TEMPS....SLIGHTLY ABOVE
NORMAL FOR THIS TIME OF YEAR.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 340 AM CDT SAT AUG 25 2012
THE MAIN CONCERN CONTINUES TO BE THE PATH OF TS ISAAC.
THE LATEST MODELS RUNS CONTINUE TO BE IN COMPLETE DISARRAY. THE 12Z
SATURDAY ECMWF FOR THE FIRST TIME TAKES THE EASTERN MOST PATH ALONG
THE EASTERN COAST. PREVIOUS 3 DAYS IT HAS RANGED FROM WESTERN MO TO
WESTERN KY SO THIS IS THE LARGEST FLIP FLOP FOR THE OPERATIONAL
ECMWF. THE LATEST 00Z SUN ECMWF ACTUALLY BRINGS THE CENTER OF THE
REMNANTS OF ISAAC OVER THE PENNYRILE AREA OF W KY. THE 00Z SUN GFS
RUN ACTUALLY BRINGS THE CENTER OF ISAAC OVER SGF. FOR THE FIRST TIME
THIS WEEK THE GFS HAS THE WESTERN TRACK AND THE ECMWF HAS THE
EASTERN TRACK. THE ENSEMBLES ARE MUCH HELP EITHER. MOST OF THE
MODELS PERFORM WELL UNTIL ISSAC MAKES LANDFALL AND THEN ITS A CRAP
SHOOT AS FAR AS THE MODELS GO. THIS UNCERTAINTY WILL WREAK HAVOC ON
TEMP FCST AS WELL. AS PREVIOUS DISC STATED IT COULD BE 70S WITH
ISSAC OVER THE AREA OR MID 90S IF IT MISSES US. SO AGAIN DRAMATIC
CHANGES SHOULD BE ANTICIPATED WITH THE EXTENDED SHOULD A REASONABLE
SOLUTION REVEAL ITSELF IN THE NEAR FUTURE. FOR NOW WILL LEAN TOWARD
THE NHC FCST AS DID HPC BUT CONFIDENCE IS EXTREMELY LOW.
FOR THE AFOREMENTIONED REASONS LITTLE CHANGE WAS MADE TO TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 313 AM CDT SUN AUG 26 2012
FOR THE MOST PART...VFR CEILINGS ARE EXPECTED TO SPREAD NORTH AND EAST
DURING THE PERIOD. SCT LIGHT RAIN SHOWERS MAY AFFECT A FEW TAF
SITES TONIGHT...BUT CONDITIONS SHOULD REMAIN MOSTLY ON THE VFR SIDE.
LIGHT SOUTH WINDS SHOULD STAY BELOW 10 KTS.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MEFFERT
LONG TERM....KH
AVIATION...MEFFERT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
944 PM EDT MON AUG 27 2012
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH OVERNIGHT AND CROSS THE AREA EARLY
TUESDAY MORNING. HIGH PRESSURE MOVING IN FROM THE WEST WILL BUILD
INTO THE EAST COAST WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...ADJUSTED THE POPS ONCE TO REFLECT THE LATEST RADAR TREND
W/A LINE OF SHOWERS AND EMBEDDED TSTMS MOVING ACROSS NORTHERN AND
WESTERN AREAS. MORE SCATTERED SHOWERS ARE NOW SHOWING UP ACROSS
PORTIONS OF THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST MAINE.
NEEDED TO ADJUST AREAL COVERAGE TO ACCOUNT FOR THESE SHOWERS. WAVE
MOVING THROUGH ONTARIO AS SEEN ON THE LATEST SATL WATER VAPOR WILL
MOVE NE OVERNIGHT WHICH WILL SLOW THE FORWARD PROGRESS OF THE
FRONT AND ENHANCE RAFL. LAPS AND RUC SOUNDINGS INDICATE ENOUGH
INSTABILITY OF TSTMS, ALTHOUGH AIRMASS HAS STABILIZED OVER THE
LAST 3 HRS. CELLS MOVING OVER THE SAME AREA OVERNIGHT INTO EARLY
TUESDAY ESPECIALLY ACROSS NORTHERN AND WESTERN AREAS WILL NEED TO
BE MONITORED FOR FLOODING CONCERNS. KEPT HEAVY RAINFALL MENTION IN
THE FCST OVERNIGHT.
REMOVED THE MENTION OF FOG AS WELL DUE TO THE FLOW BECOMING MORE
SSW AND GRADIENT TIGHTENING SOME. COORDINATED W/NERFC ON QPF AND
ADJUSTED VALUES TO REFLECT HEAVIEST RAFL ACROSS NORTHERN AND
CENTRAL AREAS.
PREVIOUS DISCUSSION...
AN AREA OF PVA AND UNSTABLE AIR AHEAD OF A STRONG COLD FRONT WILL
PRODUCE SHOWERS AND THUNDERSTORMS TONIGHT. THE SHOWERS WILL SPREAD
SOUTHWARD TOWARDS BANGOR LATER TONIGHT. THERE IS A VOLATILE
MIXTURE OF THE UNUSUALLY WARM AND HUMID AIR MASS AHEAD OF THE
FRONT WITH COOL AND DRY CANADIAN AIR BEHIND THE FRONT. THIS CLASH COULD
ALLOW SHOWERS TOWARDS THE CROWN OF MAINE TO PRODUCE SOME FAIRLY
IMPRESSIVE PRECIPITATION TOTAL..REACHING UP TO AN INCH BEFORE THE
FRONT CROSSES TOMORROW. A DEEP WARM CLOUD LAYER OVER 11000
FEET...A STRONG LLJ AND PW NEARLY 2 INCHES WILL INCREASE THE ODDS
OF LOCALLY HEAVY RAINFALL TONIGHT. THE FRONT WILL SLOWLY DRAG
THROUGH THE STATE TONIGHT AND FINALLY MOVE OFF THE COAST TUESDAY
AFTERNOON. WITH THE PRECIPITATION AND LOW LEVEL MOISTURE PRODUCING
WIDESPREAD LOW CLOUDINESS BY LATER TONIGHT...LOWS WILL ONLY DROP
TO THE LOW TO MID 60S. WITH STRONG COLD AIR ADVECTION BEHIND THE
FRONT...HIGHS TUESDAY WILL ONLY REACH THE UPPER 60S TO LOW 70S
NORTH AND MID 70S DOWN EAST. HUMIDITY WILL DROP MARKEDLY FROM
TODAY`S READINGS IN THE AIR MASS BEHIND THE FRONT THAT WILL
PROVIDE A HINT OF FALL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
COOLER AIR PUSHING INTO THE AREA AHEAD OF HIGH PRESSURE MOVING INTO
THE GREAT LAKES WILL BRING A MOSTLY CLEAR...COOL AND DRY NIGHT
TUESDAY NIGHT. THE HIGH WILL BRING A MOSTLY CLEAR AND COOL MORNING
THROUGHOUT THE REGION WEDNESDAY MORNING. A WEAK WEATHER DISTURBANCE
SLIDING IN FROM THE NORTHWEST ON WEDNESDAY WILL CARRY A BIT OF
MOISTURE WITH IT. THE MOISTURE WILL COME AS A FUNCTION OF SOME
WARM ADVECTION CIRCULATING IN FROM THE WEST JUST NORTH OF THE
HIGH PRESSURE SYSTEM. THIS WILL BRING A MOSTLY CLOUDY MIDDAY AND
AFTERNOON OVER THE NORTH WEDNESDAY WHILE DOWNEAST AREAS REMAIN
SUNNY TO PARTLY CLOUDY. CLOUDS WILL REMAIN ACROSS THE NORTH
THURSDAY NIGHT INTO FRIDAY WHILE DOWNEAST REMAINS PARTLY CLOUDY.
WARM ADVECTION MOISTURE NORTH OF THE HIGH AND JUST SOUTH OF A
SMALL LOW MOVING ACROSS CENTRAL CANADA MAY PROVIDE ENOUGH MOISTURE
TO PRODUCE A FEW SHOWERS OVER THE FAR NORTH THURSDAY AFTERNOON.
TEMPS DURING THE MID WEEK PERIOD WILL BE NEAR...TO JUST A COUPLE
DEGREES BELOW NORMAL FOR LATE AUGUST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WEAK FRONTAL BOUNDARY DRAPED ACROSS NORTHERN FORECAST AREA WILL
BEGIN TO SLOWLY PUSH NORTH OF ST JOHN VALLEY BY EARLY SATURDAY.
CHANCE OF RAINSHOWERS ACROSS MOST OF AROOSTOOK COUNTY THROUGH
SATURDAY...SLIGHT CHANCE ELSEWHERE. COLD FRONT WILL THEN MOVE IN
FROM QUEBEC THROUGH DAY SATURDAY WITH SHOWERS. COLD FRONT WILL
CLEAR ALL OF FORECAST AREA BY SUNDAY MORNING FOR A SUNNY AND DRY DAY
WITH A HINT OF EARLY FALL IN THE AIR. WEAK SHORT WAVE IN NORTHWEST
UPPER FLOW WILL AGAIN BRING SLIGHT CHANCE OF SHOWERS IN
NORTHWESTERN ZONES MONDAY AFTERNOON. TEMPERATURE WISE LOOK FOR
DAYTIME HIGHS IN LOW TO MID 70S NORTH AND NEAR 80 DOWNEAST ON
FRIDAY THEN MID TO UPPER 60S NORTH WITH MID 70S DOWNEAST SATURDAY
THROUGH MONDAY. LOWS WILL BE MID TO UPPER 50S FRIDAY
MORNING...AROUND 60 SATURDAY...THEN SHARPLY COOLER SUNDAY AND
MONDAY WITH MID 40S NORTH AND LOW 50S ELSEWHERE.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR CONDITIONS ARE EXPECT TO DEVELOP...MOSTLY AFTER
MIDNIGHT WITH THE EXCEPTIONS OF BHB AND FVE. THUNDERSTORMS ARE
POSSIBLE TONIGHT. IFR WILL CONTINUE INTO TUESDAY MORNING FOR ALL
TERMINALS. VFR RETURNS DURING THE AFTERNOON FOR ALL SITES.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY THROUGH WEDNESDAY
ACROSS THE AREA.
&&
.MARINE...
NEAR TERM: REMOVED FOG. ISOLATED THUNDERSTORMS ARE POSSIBLE. SEAS
WILL PICK UP TOWARDS 3 TO 5 FEET IN A SE SWELL OVERNIGHT AND
CONTINUE INTO TOMORROW. NO SCA IS EXPECTED. MODELS SEEM TO BE
ABOUT 1 FOOT HIGH ON GUIDANCE FOR THIS FRONT.
SHORT TERM: WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
244 PM EDT SUN AUG 26 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN AUG 26 2012
SYNOPSIS...WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL
LOW NE OF LAKE WINNIPEG RESULTING IN SW FLOW FROM THE UPPER MS VALLEY
INTO THE NRN GREAT LAKES. AT THE SFC... A COLD FRONT EXTENDED FROM A
TRIPLE POINT WEST OR JAMES BAY SW TO NEAR CYQT/KDLH. -SHRA INTO
CNTRL UPPER MI WERE SUPPORTED BY A WEAK SHRTWV OVER NRN WI IN THE
MOISTURE PLUME REACHING FROM THE SRN PLAINS INTO UPPER MI AND NRN
ONTARIO. ADDITIONAL SHRA WERE ALSO MOVING NE INTO CNTRL WI.
A LINE OF TSRA HAD DEVELOPED AHEAD N OF LAKE SUPERIOR AHEAD OF THE
COLD FRONT ASSOCIATED WITH STRONGER QVECTOR CONV AND HEIGHT FALLS
AHEAD OF THE MID LEVEL TROUGH.
TODAY AND TONIGHT...EXPECT SCT SHRA TO CONTINUE INTO THE CNTRL AND EAST CWA
THIS MORNING...PER RADAR/SATELLITE TRENDS AS ANOTHER WEAK SHORTWAVE
LIFTS TOWARD THE AREA. EVEN THOUGH THICKER CLOUD COVER WILL HOLD TEMPS
DOWN COMPARED TO SATURDAY...EVEN MODEST WARMING AHEAD OF THE FRONT
SHOULD STILL PUSH MAX READINGS TO AROUND 80. WITH THE TEMP
RECOVERY...MUCAPE VALUES MAY ALSO CLIMB INTO THE 500-1000 J/KG RANGE
TO SUPPORT TSRA CHANCES BY LATE THIS MORNING INTO THIS EVENING AS THE
COLD FRONT EDGES THROUGH THE AREA. HOWEVER...SINCE LOW LEVEL CONV AND
FORCING WITH THE FRONT WILL BE RELATIVELY WEAK...THE FCST ONLY
INCLUDES LOWER END CHANCE POPS. ANY REMAINING SHRA/TSRA WILL EXIT THE
ERN CWA AFT 03Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN AUG 26 2012
OVERALL PATTERN FOR THE LONG TERM WILL FEATURE AN UPPER TROUGH
PUSHING INTO THE UPPER GREAT LKS ON SUN NIGHT AND MON BEFORE
SHIFTING E INTO THE NEW ENGLAND STATES. THIS WILL ALLOW AN UPPER
RIDGE TO BUILD OVER THE ROCKIES AND NORTHERN PLAINS WHILE SLOWLY
SHIFTING E INTO THE UPPER MISS VALLEY FOR WED AND THE UPPER GREAT
LKS ON THURS. AT THE SFC...NW FLOW WILL TAKE HOLD FOR MON AHEAD OF
HIGH PRESSURE SLIDING OUT OF THE CANADIAN PRAIRIES AND NORTHERN
PLAINS AND INTO THE UPPER MISS VALLEY. THIS HIGH WILL SLIDE SE OVER
THE UPPER GREAT LAKES REGION FOR MON NIGHT THROUGH WED AND THEN
SLIDE SOUTHEAST INTO THE LOWER GREAT LAKES ON WED NIGHT AND THURS.
MODELS CONSISTENT ON SHORTWAVE MOVING THROUGH ON MON AFTN UNDER THE
NW FLOW ALOFT. H700-500 MOISTURE IS VERY LIMITED...WITH THE BEST
AREA OVER LK SUPERIOR AND ALIGNED WITH STEEPENING LAPSE RATES TO 6.5
C/KM. LOWER MOISTURE IS ALSO LIMITED AND MODELS TRY TO DIMINISH IT
AS IT DROPS SE ACROSS THE CWA. WITH THE MOISTURE AROUND
H850...THINKING IT SHOULD BE ENOUGH FOR AT LEAST SOME DIURNAL CU.
BUT WITH LITTLE TO NO INSTABILITY DUE TO CAPPING INVERSION BETWEEN
H800-600...DON/T EXPECT MUCH MORE THAN THAT. THEREFORE...HAVE BUMPED
THE CLOUDS UP A LITTLE OVER NRN/ERN LK SUPERIOR WHERE THE BETTER MID
LVL MOISTURE IS LOCATED AND ALSO OVER THE LAND AREAS WITH THE
DIURNAL CU.
WITH THE HIGH MOVING IN MON NIGHT...SHOULD BE A DRY PERIOD FOR MUCH
OF THE WORK WEEK. DIURNAL CU POSSIBLE AGAIN ON TUES...BUT THIS TIME
CONFINED TO THE INTERIOR CENTRL AND NEAR LK MI AS THE DRIER AIR FROM
THE HIGH SETTLES IN. UPPER TROUGH SLIDING THROUGH WITH THE CANADIAN
HIGH WILL LEAD TO COOLER TEMPERATURES FOR MON/TUES...WITH HIGHS
MAINLY IN THE 70S. THEN AS THE HIGH SHIFTS SE...SWRLY RETURN FLOW
WILL START TO PUSH TEMPS BACK UP AND ON A BREEZY THURS...HIGHS WILL
APPROACH 90 DEGREES ONCE AGAIN UNDER THE UPPER RIDGE.
THEN FOR FRI/SAT...EXTENDED MODELS AND THEIR ENS MEANS CONSISTENT ON
THE IDEA OF THE UPPER RIDGE FLATTENING OUT DUE TO A SHORTWAVE
PULLING OUT OF THE UPPER TROUGH OVER THE PAC NW. STILL SOME
DIFFERENCES IN THE INTENSITY OF THE WAVE AND THE EXACT TRACK...BUT
THE TIMING OF MOVING FROM OREGON TO NRN ONTARIO ON THURS/FRI IS
CONSISTENT. THIS WOULD LEAD TO A WEAK COLD FRONT MOVING ACROSS THE
AREA ON THURS NIGHT AND FRI. RIGHT NOW...APPEARS TO BE FAIRLY
DRY...SO WILL ONLY MENTION SLIGHT CHANCES OVER THE NW HALF OF LK
SUPERIOR. THINGS REALLY START TO DIFFER ON SAT...AS 00Z GFS WANTS TO
PULL ANOTHER UPPER WAVE ACROSS SRN ONTARIO. 00Z GFS ENS MEAN DOESN/T
FOLLOW THIS IDEA AND STAYS CLOSER TO 12Z ECMWF DETERMINISTIC AND ENS
MEAN ON WRLY FLOW. THUS...WILL FOLLOW THAT IDEA AND KEEP MUCH OF THE
AREA DRY AND CONTINUE THE ABOVE NORMAL TEMPS WITH HIGHS IN THE UPPER
70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 243 PM EDT SUN AUG 26 2012
PLENTY OF CLOUDS OVERHEAD HAVE HELPED REDUCE THE THREAT OF
REDEVELOPMENT AND POSSIBLE TS ACTIVITY NEAR THE WEAKENING COLD FRONT
PUSHING ACROSS THE W HALF OF UPPER MI. OTHER THAN A TEMPORARY MVFR
CEILING AT CMX...EXPECT VFR CEILINGS AND VIS TO REMAIN THROUGH THE
NEXT 24 HOURS. WINDS SHOULD DIMINISH TO AROUND 6KTS OR LESS
OVERNIGHT...BEFORE INCREASING OUT OF THE NW MONDAY...STEADY NEAR
10KTS WITH A FEW SLIGHTLY HIGHER GUSTS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN AUG 26 2012
WINDS ARE EXPECTED TO REMAIN BELOW 30KTS THROUGH THE FORECAST PERIOD.
LOW PRES OVER CENTRAL MANITOBA LOW PRESSURE WILL LIFT ACROSS HUDSON
BAY TODAY...AND NORTHERN QUEBEC ON MONDAY. THIS WILL KEEP A TROUGH
ACROSS LAKE SUPERIOR THROUGH SUNDAY NIGHT. HIGH PRESSURE STRETCHING
FROM MANITOBA THE CENTRAL PLAINS MONDAY MORNING WILL SLOWLY BUILD
ACROSS THE UPPER GREAT LAKES THROUGH TUESDAY...BEFORE SINKING TO THE
LOWER GREAT LAKES WEDNESDAY. A LOW WILL SLIDE FROM CENTRAL MANITOBA
TO CENTRAL ONTARIO AND HUDSON BAY BY THURSDAY EVENING...ALLOWING A
TROUGH TO DIP OVER LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
741 AM EDT SUN AUG 26 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN AUG 26 2012
SYNOPSIS...WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL
LOW NE OF LAKE WINNIPEG RESULTING IN SW FLOW FROM THE UPPER MS VALLEY
INTO THE NRN GREAT LAKES. AT THE SFC... A COLD FRONT EXTENDED FROM A
TRIPLE POINT WEST OR JAMES BAY SW TO NEAR CYQT/KDLH. -SHRA INTO
CNTRL UPPER MI WERE SUPPORTED BY A WEAK SHRTWV OVER NRN WI IN THE
MOISTURE PLUME REACHING FROM THE SRN PLAINS INTO UPPER MI AND NRN
ONTARIO. ADDITIONAL SHRA WERE ALSO MOVING NE INTO CNTRL WI.
A LINE OF TSRA HAD DEVELOPED AHEAD N OF LAKE SUPERIOR AHEAD OF THE
COLD FRONT ASSOCIATED WITH STRONGER QVECTOR CONV AND HEIGHT FALLS
AHEAD OF THE MID LEVEL TROUGH.
TODAY AND TONIGHT...EXPECT SCT SHRA TO CONTINUE INTO THE CNTRL AND EAST CWA
THIS MORNING...PER RADAR/SATELLITE TRENDS AS ANOTHER WEAK SHORTWAVE
LIFTS TOWARD THE AREA. EVEN THOUGH THICKER CLOUD COVER WILL HOLD TEMPS
DOWN COMPARED TO SATURDAY...EVEN MODEST WARMING AHEAD OF THE FRONT
SHOULD STILL PUSH MAX READINGS TO AROUND 80. WITH THE TEMP
RECOVERY...MUCAPE VALUES MAY ALSO CLIMB INTO THE 500-1000 J/KG RANGE
TO SUPPORT TSRA CHANCES BY LATE THIS MORNING INTO THIS EVENING AS THE
COLD FRONT EDGES THROUGH THE AREA. HOWEVER...SINCE LOW LEVEL CONV AND
FORCING WITH THE FRONT WILL BE RELATIVELY WEAK...THE FCST ONLY
INCLUDES LOWER END CHANCE POPS. ANY REMAINING SHRA/TSRA WILL EXIT THE
ERN CWA AFT 03Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN AUG 26 2012
OVERALL PATTERN FOR THE LONG TERM WILL FEATURE AN UPPER TROUGH
PUSHING INTO THE UPPER GREAT LKS ON SUN NIGHT AND MON BEFORE
SHIFTING E INTO THE NEW ENGLAND STATES. THIS WILL ALLOW AN UPPER
RIDGE TO BUILD OVER THE ROCKIES AND NORTHERN PLAINS WHILE SLOWLY
SHIFTING E INTO THE UPPER MISS VALLEY FOR WED AND THE UPPER GREAT
LKS ON THURS. AT THE SFC...NW FLOW WILL TAKE HOLD FOR MON AHEAD OF
HIGH PRESSURE SLIDING OUT OF THE CANADIAN PRAIRIES AND NORTHERN
PLAINS AND INTO THE UPPER MISS VALLEY. THIS HIGH WILL SLIDE SE OVER
THE UPPER GREAT LAKES REGION FOR MON NIGHT THROUGH WED AND THEN
SLIDE SOUTHEAST INTO THE LOWER GREAT LAKES ON WED NIGHT AND THURS.
MODELS CONSISTENT ON SHORTWAVE MOVING THROUGH ON MON AFTN UNDER THE
NW FLOW ALOFT. H700-500 MOISTURE IS VERY LIMITED...WITH THE BEST
AREA OVER LK SUPERIOR AND ALIGNED WITH STEEPENING LAPSE RATES TO 6.5
C/KM. LOWER MOISTURE IS ALSO LIMITED AND MODELS TRY TO DIMINISH IT
AS IT DROPS SE ACROSS THE CWA. WITH THE MOISTURE AROUND
H850...THINKING IT SHOULD BE ENOUGH FOR AT LEAST SOME DIURNAL CU.
BUT WITH LITTLE TO NO INSTABILITY DUE TO CAPPING INVERSION BETWEEN
H800-600...DON/T EXPECT MUCH MORE THAN THAT. THEREFORE...HAVE BUMPED
THE CLOUDS UP A LITTLE OVER NRN/ERN LK SUPERIOR WHERE THE BETTER MID
LVL MOISTURE IS LOCATED AND ALSO OVER THE LAND AREAS WITH THE
DIURNAL CU.
WITH THE HIGH MOVING IN MON NIGHT...SHOULD BE A DRY PERIOD FOR MUCH
OF THE WORK WEEK. DIURNAL CU POSSIBLE AGAIN ON TUES...BUT THIS TIME
CONFINED TO THE INTERIOR CENTRL AND NEAR LK MI AS THE DRIER AIR FROM
THE HIGH SETTLES IN. UPPER TROUGH SLIDING THROUGH WITH THE CANADIAN
HIGH WILL LEAD TO COOLER TEMPERATURES FOR MON/TUES...WITH HIGHS
MAINLY IN THE 70S. THEN AS THE HIGH SHIFTS SE...SWRLY RETURN FLOW
WILL START TO PUSH TEMPS BACK UP AND ON A BREEZY THURS...HIGHS WILL
APPROACH 90 DEGREES ONCE AGAIN UNDER THE UPPER RIDGE.
THEN FOR FRI/SAT...EXTENDED MODELS AND THEIR ENS MEANS CONSISTENT ON
THE IDEA OF THE UPPER RIDGE FLATTENING OUT DUE TO A SHORTWAVE
PULLING OUT OF THE UPPER TROUGH OVER THE PAC NW. STILL SOME
DIFFERENCES IN THE INTENSITY OF THE WAVE AND THE EXACT TRACK...BUT
THE TIMING OF MOVING FROM OREGON TO NRN ONTARIO ON THURS/FRI IS
CONSISTENT. THIS WOULD LEAD TO A WEAK COLD FRONT MOVING ACROSS THE
AREA ON THURS NIGHT AND FRI. RIGHT NOW...APPEARS TO BE FAIRLY
DRY...SO WILL ONLY MENTION SLIGHT CHANCES OVER THE NW HALF OF LK
SUPERIOR. THINGS REALLY START TO DIFFER ON SAT...AS 00Z GFS WANTS TO
PULL ANOTHER UPPER WAVE ACROSS SRN ONTARIO. 00Z GFS ENS MEAN DOESN/T
FOLLOW THIS IDEA AND STAYS CLOSER TO 12Z ECMWF DETERMINISTIC AND ENS
MEAN ON WRLY FLOW. THUS...WILL FOLLOW THAT IDEA AND KEEP MUCH OF THE
AREA DRY AND CONTINUE THE ABOVE NORMAL TEMPS WITH HIGHS IN THE UPPER
70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 739 AM EDT SUN AUG 26 2012
A SLOW MOVING LOW PRES TROUGH WILL BRING THE THREAT OF SOME -SHRA
AND PERHAPS A TS W-E TO MAINLY CMX/SAW TODAY. THE QUICKER PASSAGE OF
THIS BOUNDARY THIS AFTN AND AN INFLUX OF DRIER AIR IN ITS WAKE WILL
END THE PCPN THREAT AT IWD/CMX EARLIER THAN AT SAW. TS CHANCES ARE
TOO LOW TO BE SPECIFIC FOR TIMING ATTM...BUT THE BEST SHOT FOR A TS
WOULD BE LATE TODAY AT SAW. ALTHOUGH MVFR CONDITIONS ARE POSSIBLE
IMMEDIATELY AHEAD OF THE COLD FROPA AT ALL 3 SITES AND UNDER ANY
HEAVIER SHRA...LACK OF SIGNIFICANT LOW LEVEL MOISTENING SUGGESTS VFR
CONDITIONS WILL PREVAIL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN AUG 26 2012
WINDS ARE EXPECTED TO REMAIN BELOW 30KTS THROUGH THE FORECAST PERIOD.
LOW PRES OVER CENTRAL MANITOBA LOW PRESSURE WILL LIFT ACROSS HUDSON
BAY TODAY...AND NORTHERN QUEBEC ON MONDAY. THIS WILL KEEP A TROUGH
ACROSS LAKE SUPERIOR THROUGH SUNDAY NIGHT. HIGH PRESSURE STRETCHING
FROM MANITOBA THE CENTRAL PLAINS MONDAY MORNING WILL SLOWLY BUILD
ACROSS THE UPPER GREAT LAKES THROUGH TUESDAY...BEFORE SINKING TO THE
LOWER GREAT LAKES WEDNESDAY. A LOW WILL SLIDE FROM CENTRAL MANITOBA
TO CENTRAL ONTARIO AND HUDSON BAY BY THURSDAY EVENING...ALLOWING A
TROUGH TO DIP OVER LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 AM EDT SUN AUG 26 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT SUN AUG 26 2012
SYNOPSIS...WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL
LOW NE OF LAKE WINNIPEG RESULTING IN SW FLOW FROM THE UPPER MS VALLEY
INTO THE NRN GREAT LAKES. AT THE SFC... A COLD FRONT EXTENDED FROM A
TRIPLE POINT WEST OR JAMES BAY SW TO NEAR CYQT/KDLH. -SHRA INTO
CNTRL UPPER MI WERE SUPPORTED BY A WEAK SHRTWV OVER NRN WI IN THE
MOISTURE PLUME REACHING FROM THE SRN PLAINS INTO UPPER MI AND NRN
ONTARIO. ADDITIONAL SHRA WERE ALSO MOVING NE INTO CNTRL WI.
A LINE OF TSRA HAD DEVELOPED AHEAD N OF LAKE SUPERIOR AHEAD OF THE
COLD FRONT ASSOCIATED WITH STRONGER QVECTOR CONV AND HEIGHT FALLS
AHEAD OF THE MID LEVEL TROUGH.
TODAY AND TONIGHT...EXPECT SCT SHRA TO CONTINUE INTO THE CNTRL AND EAST CWA
THIS MORNING...PER RADAR/SATELLITE TRENDS AS ANOTHER WEAK SHORTWAVE
LIFTS TOWARD THE AREA. EVEN THOUGH THICKER CLOUD COVER WILL HOLD TEMPS
DOWN COMPARED TO SATURDAY...EVEN MODEST WARMING AHEAD OF THE FRONT
SHOULD STILL PUSH MAX READINGS TO AROUND 80. WITH THE TEMP
RECOVERY...MUCAPE VALUES MAY ALSO CLIMB INTO THE 500-1000 J/KG RANGE
TO SUPPORT TSRA CHANCES BY LATE THIS MORNING INTO THIS EVENING AS THE
COLD FRONT EDGES THROUGH THE AREA. HOWEVER...SINCE LOW LEVEL CONV AND
FORCING WITH THE FRONT WILL BE RELATIVELY WEAK...THE FCST ONLY
INCLUDES LOWER END CHANCE POPS. ANY REMAINING SHRA/TSRA WILL EXIT THE
ERN CWA AFT 03Z.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 503 AM EDT SUN AUG 26 2012
OVERALL PATTERN FOR THE LONG TERM WILL FEATURE AN UPPER TROUGH
PUSHING INTO THE UPPER GREAT LKS ON SUN NIGHT AND MON BEFORE
SHIFTING E INTO THE NEW ENGLAND STATES. THIS WILL ALLOW AN UPPER
RIDGE TO BUILD OVER THE ROCKIES AND NORTHERN PLAINS WHILE SLOWLY
SHIFTING E INTO THE UPPER MISS VALLEY FOR WED AND THE UPPER GREAT
LKS ON THURS. AT THE SFC...NW FLOW WILL TAKE HOLD FOR MON AHEAD OF
HIGH PRESSURE SLIDING OUT OF THE CANADIAN PRAIRIES AND NORTHERN
PLAINS AND INTO THE UPPER MISS VALLEY. THIS HIGH WILL SLIDE SE OVER
THE UPPER GREAT LAKES REGION FOR MON NIGHT THROUGH WED AND THEN
SLIDE SOUTHEAST INTO THE LOWER GREAT LAKES ON WED NIGHT AND THURS.
MODELS CONSISTENT ON SHORTWAVE MOVING THROUGH ON MON AFTN UNDER THE
NW FLOW ALOFT. H700-500 MOISTURE IS VERY LIMITED...WITH THE BEST
AREA OVER LK SUPERIOR AND ALIGNED WITH STEEPENING LAPSE RATES TO 6.5
C/KM. LOWER MOISTURE IS ALSO LIMITED AND MODELS TRY TO DIMINISH IT
AS IT DROPS SE ACROSS THE CWA. WITH THE MOISTURE AROUND
H850...THINKING IT SHOULD BE ENOUGH FOR AT LEAST SOME DIURNAL CU.
BUT WITH LITTLE TO NO INSTABILITY DUE TO CAPPING INVERSION BETWEEN
H800-600...DON/T EXPECT MUCH MORE THAN THAT. THEREFORE...HAVE BUMPED
THE CLOUDS UP A LITTLE OVER NRN/ERN LK SUPERIOR WHERE THE BETTER MID
LVL MOISTURE IS LOCATED AND ALSO OVER THE LAND AREAS WITH THE
DIURNAL CU.
WITH THE HIGH MOVING IN MON NIGHT...SHOULD BE A DRY PERIOD FOR MUCH
OF THE WORK WEEK. DIURNAL CU POSSIBLE AGAIN ON TUES...BUT THIS TIME
CONFINED TO THE INTERIOR CENTRL AND NEAR LK MI AS THE DRIER AIR FROM
THE HIGH SETTLES IN. UPPER TROUGH SLIDING THROUGH WITH THE CANADIAN
HIGH WILL LEAD TO COOLER TEMPERATURES FOR MON/TUES...WITH HIGHS
MAINLY IN THE 70S. THEN AS THE HIGH SHIFTS SE...SWRLY RETURN FLOW
WILL START TO PUSH TEMPS BACK UP AND ON A BREEZY THURS...HIGHS WILL
APPROACH 90 DEGREES ONCE AGAIN UNDER THE UPPER RIDGE.
THEN FOR FRI/SAT...EXTENDED MODELS AND THEIR ENS MEANS CONSISTENT ON
THE IDEA OF THE UPPER RIDGE FLATTENING OUT DUE TO A SHORTWAVE
PULLING OUT OF THE UPPER TROUGH OVER THE PAC NW. STILL SOME
DIFFERENCES IN THE INTENSITY OF THE WAVE AND THE EXACT TRACK...BUT
THE TIMING OF MOVING FROM OREGON TO NRN ONTARIO ON THURS/FRI IS
CONSISTENT. THIS WOULD LEAD TO A WEAK COLD FRONT MOVING ACROSS THE
AREA ON THURS NIGHT AND FRI. RIGHT NOW...APPEARS TO BE FAIRLY
DRY...SO WILL ONLY MENTION SLIGHT CHANCES OVER THE NW HALF OF LK
SUPERIOR. THINGS REALLY START TO DIFFER ON SAT...AS 00Z GFS WANTS TO
PULL ANOTHER UPPER WAVE ACROSS SRN ONTARIO. 00Z GFS ENS MEAN DOESN/T
FOLLOW THIS IDEA AND STAYS CLOSER TO 12Z ECMWF DETERMINISTIC AND ENS
MEAN ON WRLY FLOW. THUS...WILL FOLLOW THAT IDEA AND KEEP MUCH OF THE
AREA DRY AND CONTINUE THE ABOVE NORMAL TEMPS WITH HIGHS IN THE UPPER
70S AND LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 149 AM EDT SUN AUG 26 2012
A SLOW MOVING LO PRES TROF WILL BRING THE THREAT OF SOME -SHRA AND
PERHAPS A TS W-E TO THE 3 SITES DURING AT LEAST PART OF THIS FCST
PERIOD. THE QUICKER PASSAGE OF THIS BNDRY THIS AFTN AND AN INFLUX OF
DRIER AIR IN ITS WAKE WL END THE PCPN THREAT AT IWD/CMX EARLIER THAN
AT SAW. TS CHCS ARE TOO LO TO BE SPECIFIC FOR TIMING ATTM...BUT THE
BEST SHOT FOR A TS WOULD BE LATE TODAY AT SAW. ALTHOUGH MVFR
CONDITIONS ARE PSBL IMMEDIATELY AHEAD OF THE COLD FROPA AT ALL 3
SITES AND UNDER ANY HEAVIER SHRA...LACK OF SGNFT LLVL MOISTENING
SUGS VFR CONDITIONS WL PREVAIL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT SUN AUG 26 2012
WINDS ARE EXPECTED TO REMAIN BELOW 30KTS THROUGH THE FORECAST PERIOD.
LOW PRES OVER CENTRAL MANITOBA LOW PRESSURE WILL LIFT ACROSS HUDSON
BAY TODAY...AND NORTHERN QUEBEC ON MONDAY. THIS WILL KEEP A TROUGH
ACROSS LAKE SUPERIOR THROUGH SUNDAY NIGHT. HIGH PRESSURE STRETCHING
FROM MANITOBA THE CENTRAL PLAINS MONDAY MORNING WILL SLOWLY BUILD
ACROSS THE UPPER GREAT LAKES THROUGH TUESDAY...BEFORE SINKING TO THE
LOWER GREAT LAKES WEDNESDAY. A LOW WILL SLIDE FROM CENTRAL MANITOBA
TO CENTRAL ONTARIO AND HUDSON BAY BY THURSDAY EVENING...ALLOWING A
TROUGH TO DIP OVER LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1155 PM CDT SAT AUG 25 2012
.UPDATED FOR 06Z AVIATION DISCUSSION...
&&
.DISCUSSION...
A DUO OF WEAK SHORTWAVES IS DETECTABLE IN EARLY AFTERNOON RADAR
IMAGERY...ONE ROTATING FROM EAST CENTRAL MN INTO WEST CENTRAL
WISCONSIN...AND THE OTHER OVER NORTHEAST IA. MEANWHILE...THE
PRECIPITATION ASSOCIATED WITH THE NORTHERN STREAM TROUGH OVER
NORTHWEST ONTARIO IS SHIFTING TOWARD LAKE SUPERIOR. THE DYNAMICS
AND 850-700MB MOISTURE TRANSPORT ASSOCIATED WITH THESE FEATURES
WILL CONTINUE SHIFTING EAST OF THE FORECAST AREA DURING THE LATE
AFTERNOON AND EARLY EVENING...WITH ONLY WIDELY SCATTERED SHOWERS
LINGERING OVER WEST CENTRAL WI AFTER DARK. CONCERN THEN SHIFTS TO
CLOUD COVER AND THE POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT.
SURFACE COLD FRONT HAS ENTERED WEST/NORTH CENTRAL MN
TODAY...ALTHOUGH IT WILL WASH OUT PRIOR TO REACHING CENTRAL MN.
WHILE POST-FRONTAL DEWPOINTS ARE IN THE MID TO UPPER 40S...PRE-
FRONTAL DEWPOINTS BETWEEN 65 AND 70 DEGREES ARE COMMON THIS
AFTERNOON ACROSS THE CWFA. THEREFORE...GIVEN THE LIGHT WIND
FIELD...AREAS THAT ARE ABLE TO CLEAR OUT TONIGHT WILL BE
SUSCEPTIBLE TO FOG DEVELOPMENT. THIS APPEARS MOST LIKELY ACROSS
WEST CENTRAL MN. FOR SOUTH CENTRAL MN...SHORT RANGE
MODELS...INCLUDING THE RAP AND THE NAM...INDICATE STRATUS CLOUDS
WILL LIFT OUT OF IOWA OVERNIGHT...SO LOW CEILINGS WILL BE MORE OF
A CONCERN THERE.
ON SUNDAY...A FEW SHOWERS MAY BE LINGERING FROM NEAR EAU CLAIRE TO
LADYSMITH IN THE MORNING. AN OTHERWISE DRY DAY IS EXPECTED...AS THE
AREA REMAINS SANDWICHED BETWEEN THE HUDSON BAY CYCLONE AND THE
AMPLIFYING WESTERN RIDGE. AFTER MORNING FOG AND LINGERING LOW CLOUDS
CLEAR...TEMPERATURES WILL REBOUND INTO THE LOW/MID 80S DURING THE
AFTERNOON UNDER MOSTLY SUNNY SKIES AND LIGHT WEST/SOUTHWEST WINDS.
THE MAIN WEATHER HEADLINE FOR THE UPCOMING WEEK WILL BE VERY WARM
TEMPERATURES...AS THE WESTERN RIDGE EXPANDS INTO THE CENTRAL UNITED
STATE. BY MID WEEK...TEMPERATURES WILL BE AROUND 15 DEGREES ABOVE
NORMAL...WITH HIGHS IN THE UPPER 80S TO LOWER 90S COMMON FROM
TUESDAY THROUGH THURSDAY. STILL CAN/T RULE OUT AN ARBITRARY SHOWER OR
THUNDERSTORM...BUT NO ORGANIZED PRECIPITATION IS ANTICIPATED THROUGH
NEXT WEEK.
THE RIDGE IS EXPECTED TO FLATTEN TOWARD THE END OF THE WORK WEEK
INTO LABOR DAY WEEKEND AS A SHORTWAVE TROUGH TRACKS ACROSS THE
PACIFIC NORTHWEST. THE EVOLUTION OF TC ISAAC WILL COME INTO PLAY
HOWEVER...AND FACTOR INTO HOW MUCH OF A COOL DOWN WE WILL SEE NEXT
WEEKEND. FORECAST CONFIDENCE AFTER FRIDAY IS THEREFORE RATHER LOW.
&&
.AVIATION.../00Z TAF ISSUANCE/
IFR/LIFR CIGS AND FOG THE MAIN CONCERN FOR THE MORNING. STRATUS AND
FOG DEVELOPING OVER WESTERN AREAS WHERE HIGHER CLOUDS CLEARED
EARLIER. SOME DRIER AIR OFF TO THE WEST...WORKING ALONG THE WESTERN
PERIPHERY...BUT BELIEVE WILL LIKELY SEE STRATUS CONTINUE TO DEVELOP
OVERNIGHT...WITH LOWERING VSBYS. FATHER EAST...MVFR CONDITIONS
SHOULD PREVAIL...BECOMING IFR 10Z-13Z. CONDITIONS IMPROVE BY 15Z MOST
AREAS WITH SUNSHINE EXPECTED WEST...PERHAPS SOME RESIDUAL CUMULUS
OVER THE EAST DURING THE DAY. LIGHT SOUTH WINDS BECOMING WEST
DURING THE DAY SUNDAY. SHOULD REMAIN LESS THAN 10 KNOTS.
KMSP...WILL MENTION MVFR CONDITIONS DEVELOPING EARLY...POSSIBLY
BECOMING IFR CIGS AND PERHAPS VSBYS 10Z-12Z. EXPECT CONDITIONS TO
IMPROVE THROUGH 15Z WITH PERHAPS SOME RESIDUAL CUMULUS. LIGHT SOUTH
WINDS BECOMING SOUTHWEST AND EVENTUAL WEST BY NOON SUNDAY. VFR
CONDITIONS WILL PREVAIL THROUGH THE REMAINDER OF THE PERIOD.
/OUTLOOK FOR KMSP/
MONDAY...VFR. WINDS NW AT 10 KTS.
TUESDAY...VFR. WINDS S AT 5KTS.
WEDNESDAY...VFR WITH POSSIBLE MVFR CLOUDS. WINDS SSW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/DE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1202 AM CDT SUN AUG 26 2012
.UPDATE...
ISSUED AT 826 PM CDT SAT AUG 25 2012
REASONING PROVIDED BY PREVIOUS SHIFT STILL APPLIES. MAINLY
AFTERNOON DIURNALLY DRIVEN SHOWERS AND ISOLATED THUNDERSTORMS HAVE
DECREASED IN AREAL COVERAGE EARLY THIS EVENING. STILL BELIEVE THAT
AREA OF SHRA AND ISOLATED THUNDERSTORMS GETTING READY TO ENTER
WESTERN MO WILL CONTINUE TO PUSH EASTWARD TONIGHT WHICH WILL
INCREASE CHANCES OF RAIN AFTER MIDNIGHT. THIS AREA IS MAINLY
DRIVEN BY ASCENT FROM UPPER MIDWEST/CENTRAL PLAINS TROUGH. RAP IS
ALSO SHOWING AN IN INCREASE IN LOW LEVEL MOISTURE CONVERGENCE OVER
MUCH OF THE CWA AFTER MIDNIGHT AS LOW LEVEL JET INCREASES MOISTURE
TRANSPORT INTO THE AREA. THIS IS ALREADY HANDLED WELL BY GOING
FORECAST AND HAVE MADE ONLY MINOR TWEAKS IN TIMING THROUGH EARLY
TOMORROW. GOING POPS STILL LOOK GOOD FOR TOMORROW/TOMORROW NIGHT
AS TROUGH MOVES ACROSS THE CWA.
BRITT
&&
.SHORT TERM...
ISSUED AT 258 PM CDT SAT AUG 25 2012
(TONIGHT THROUGH MONDAY NIGHT)
BOUNDARY LAYER MOISTURE WILL CONTINUE TO INCREASE AHEAD OF A VERY
SLOW EASTWARD MOVING 500MB SHORTWAVE ACROSS KANSAS/OKLAHOMA THANKS
TO A 20-30KT LOW LEVEL JET. ISOLATED/SCATTERED CONVECTION POSSIBLE
TONIGHT IN THIS WARM ADVECTION REGIME...BUT COVERAGE SHOULD REMAIN
GREATEST WEST WHICH WILL BE CLOSER TO THE SHORTWAVE AND SURFACE
TROF. PWAT VALUES NEAR 2.0 INCHES SHOULD MAKE SOME VERY EFFECTIVE
RAIN PRODUCING SHOWERS/STORMS.
LOOK FOR HEAVIEST PRECIPITATION AXIS TO SLOWLY SHIFT EAST ACROSS THE
AREA ON SUNDAY AND SUNDAY NIGHT AS THE SHORTWAVE AND SURFACE
TROF/WEAK LOW MOVE ACROSS THE CWA. SUNDAY HIGH TEMPERATURES WILL
DEPEND ON CLOUD AND PRECIPITATION COVERAGE. THINKING THERE SHOULD BE
A GRADIENT FROM NORTHWEST(BELOW AVERAGE) TO SOUTHEAST(ABOVE
AVERAGE).
THUNDERSTORM CHANCES WILL SHIFT INTO THE SOUTHERN HALF OF THE CWA ON
MONDAY WITH THE SURFACE TROF/FRONT SETTLING SOUTHWARD. THE CHANCE OF
RAIN WILL END FOR THE ENTIRE AREA MON NGT AS HIGH PRESSURE BUILDS
SOUTH FROM THE UPPER MIDWEST.
CVKING
&&
.LONG TERM...
ISSUED AT 258 PM CDT SAT AUG 25 2012
(TUESDAY THROUGH SATURDAY)
AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION NEXT WEEK...WITH
A RETURN OF ABOVE NORMAL TEMPERATURES TO END THE MONTH OF AUGUST.
HAVE MY DOUBTS ON HOW MUCH IMPACT ISAAC WILL HAVE ON THE
FORECAST...EVEN WITH THE LATEST GFS RUN BRINGING THE REMNANTS
OVERHEAD BY THE END OF THE WORK WEEK AND NEXT WEEKEND. THIS TRACK
IS CLIMATOLOGICALLY NOT FAVORED...AS RECURVE OF THESE TROPICAL
SYSTEMS NORMALLY FAVORS A LANDFALL OF WESTERN LOUISIANA OR TEXAS
FOR OUR CWA TO SEE ANY IMPACT. HAVE FOLLOWED HPC GUIDANCE PRETTY
CLOSELY IN THE EXTENDED WHICH FAVORS A TRACK MUCH FURTHER EAST
AFTER LANDFALL SIMILAR TO THE 12Z ECWMF.
CVKING
&&
.AVIATION...
ISSUED AT 1156 PM CDT SAT AUG 25 20112
CHALLENGE IN THE FORECAST WILL BE TIMING OF THE PRECIPITATION WITH
THE WEAKENING UPPER LOW WHICH WILL MERGE WITH THE NORTHERN WAVE
THAT WILL DIVE INTO THE OHIO VALLEY MONDAY. PRECIP OVER WESTERM MO
SLOWLY MOVING EAST SO WILL TRY TO TIME ARRIVAL INTO COUN AND UIN
ACCORDINGLY. SCT AREAS OF MVFR CEILINGS ALSO FLOATING AROUND
CAUSING SOME PROBLEMS...ALTHOUGH COVERAGE IS LESS THAN GUIDANCE
INDICATES.
SPECIFICS FOR KSTL...SOME MVFR CLOUDS FLOATING AROUND BUT DO NOT
EXPECT THEM TO LAST SO MOSTLY VFR OVERNIGHT. EXPECT PRECIP TO MOVE
IN SLOWLY SUNDAY...INCREASE IN COVERAGE DURING THE
AFTERNOON...FALL APART SOME EARLY EVENING BEFORE THE UPPER TROF
AND WIDER COVERAGE ARRIVES BY 06Z SUNDAY. SHRA AND MVFR CEILINGS
POSSIBLE AFTER THAT TIME FRAME.
JPK
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1239 PM CDT SUN AUG 26 2012
.AVIATION...
VFR CONDITIONS TO PREVAIL ACROSS MUCH OF THE FORECAST REGION THROUGH
THE TAF FORECAST PERIOD. MODEL GUIDANCE STILL INDICATES THE
POTENTIAL OF THUNDERSTORM DEVELOPMENT ACROSS THE EASTERN PANHANDLE
OF NEBRASKA LATE THIS AFTERNOON/EVENING. MODEL SOUNDINGS WOULD
SUGGEST HIGH BASED STORMS CAPABLE OF MARGINAL HAIL...AND STRONG
ERRATIC WIND. OTHERWISE...MODEL GUIDANCE IS HINTING AT A RETURN OF
GROUND FOG AT THE KLBF TERMINAL FROM 27.09Z-27.15Z...FORECAST
CONFIDENCE OF LOW FOG DEVELOPMENT IS LESS THAN 20 PERCENT...SO WILL
LEAVE OUT FOR NOW.
&&
PREV DISCUSSION... /ISSUED 339 AM CDT SUN AUG 26 2012/
SHORT TERM...TODAY THROUGH WEDNESDAY
PRIMARY CONCERNS FOR THE FORECAST ARE THUNDERSTORM CHANCES THIS
AFTERNOON AND EVENING AND AGAIN MONDAY EVENING...AS WELL AS
TEMPERATURES. ALSO KEEPING AN EYE ON FIRE CONCERNS THROUGH THE
FIRST HALF OF THE WEEK.
WATER VAPOR IMAGERY THIS MORNING WAS SHOWING THE UPPER LEVEL
SHORTWAVE TROUGH WHICH PUSHED THE COLD FRONT ACROSS THE FORECAST
AREA ON SATURDAY LOCATED FROM CENTRAL KANSAS INTO WISCONSIN.
THE FRONT HAD STALLED OUT JUST TO THE EAST OF THE FORECAST AREA
AND HAD SINCE WASHED OUT...WITH HIGH PRESSURE NOW CENTERED OVER
WESTERN NEBRASKA. THE DEWPOINT GRADIENT REMAINS...WITH MOIST AIR
OVER EASTERN NEBRASKA /60 DEGREE DEWPOINTS ALONG AND EAST OF A KMCK
TO KBBW TO KONL LINE/...WITH VALUES IN THE 30S OVER THE NORTHERN
PANHANDLE. THUNDERSTORMS WERE ONGOING AHEAD OF THE SYSTEM...INTO
IOWA AND MISSOURI...WHILE STRATUS AND FOG WERE OBSERVED ACROSS
MUCH OF EASTERN NEBRASKA.
ONCE AGAIN LOOKING AT THE LARGE SCALE FLOW...THE UPPER LEVEL RIDGE
WAS CENTERED OVER THE SOUTHERN ROCKY MOUNTAIN RANGE. ALSO OF
NOTE...TROPICAL STORM ISAAC REMAINS A FOCAL POINT WITH THE CENTER
CURRENTLY MOVING OVER CUBA.
THE LOCAL FORECAST AREA IS RIGHT ON THE EDGE OF THE LOW LEVEL
MOISTURE AND FOG THIS MORNING. THE RAP SEEMS TO HAVE A GOOD HANDLE
ON THIS MOISTURE AND SHOWS IT DISSIPATING BY 16Z. WITH THE
PLACEMENT OF THE MOISTURE...AND THAT THE MODELS ARE PUSHING THE
SURFACE LOW INTO THE PANHANDLE TO TIGHTEN THE PRESSURE GRADIENT
AND INCREASE THE WIND...THIS SEEMS LIKE A GOOD SOLUTION AND WILL
FOLLOW THIS LEAD INTO THE FORECAST FOR TODAY. WITH THE EARLY
DISMISSAL OF THE CLOUDS...AND RETURN FLOW...WOULD EXPECT STRONG
WARMING TODAY. TEMPERATURES DO WARM A FEW DEGREES ALOFT FROM WHAT
WAS OBSERVED ON SATURDAY...ALTHOUGH SOUNDINGS ARE INDICATING FULL
MIXING WON/T BE REALIZED. HOWEVER WITH THE EXTRA HOURS OF
SUNSHINE...BELIEVE 90S ARE ATTAINABLE FOR TODAY IN MOST LOCATIONS.
AN UPPER LEVEL SHORTWAVE TROUGH WAS OBSERVED EARLY THIS MORNING
MOVING INTO WYOMING. THIS ENERGY WILL BE THE FOCUS FOR
THUNDERSTORM DEVELOPMENT LATER TODAY. ALTHOUGH THE RETURN FLOW
DOESN/T LOOK PARTICULARLY STRONG UNTIL LATER THIS EVENING...BOTH
THE NAM AND GFS INCREASE PRECIPITABLE WATER TO VALUES OF AN INCH
OR MORE /120 PERCENT OF NORMAL/ OVER THE PANHANDLE /JUST FOR
REFERENCE THE 26.00Z LBF SOUNDING OBSERVED PW OF 0.67...WHILE RAP
HAD 0.43/. EVEN IF THE MOISTURE DOESN/T INCREASE THIS MUCH...THERE
SHOULD BE ENOUGH TO ALLOW FOR ISOLATED THUNDERSTORMS TO DEVELOP
OVER THE PANHANDLE LATER THIS AFTERNOON. SOUNDINGS SHOWING
INVERTED-V PROFILE SO WILL CONTINUE TO SEE THE THREATS FOR STRONG
AND ERRATIC WINDS FROM ANY STORMS...AS WELL AS LOW RAINFALL
AMOUNTS AND A CHANCE FOR SOME STRAY DRY LIGHTNING STRIKES. GOING
EASTWARD...MOISTURE INCREASE ISN/T AS SUBSTANTIAL...AND WITH LARGE
SCALE FORCING BEING LESS...THESE AREAS WILL STAY CAPPED SO WILL
KEEP AREAS EAST OF A LINE FROM NORTH PLATTE TO AINSWORTH DRY.
MONDAY WILL BE A SIMILAR DAY TO SUNDAY...WITH STRONG WARMING
EXPECTED WITH LOTS OF SUNSHINE AND HIGHS IN THE 90S. ALTHOUGH THE
RIDGE WILL BUILD INTO THE PLAINS THROUGH THE DAY...A DECENT
SHORTWAVE TROUGH IS SIGNALED TO PUSH OVER THE RIDGE AND INTO
NEBRASKA IN THE AFTERNOON. THIS SIGNAL WAS BEING PICKED UP BY THE
ECMWF/NAM/GEM-REGIONAL/SREF...AND WITH THE PROPER PLACEMENT OF THE
RIDGE...FELT IT WAS FITTING TO ADD A SLIGHT CHANCE OVER TH
PANHANDLE AND FAR NORTHWEST NEBRASKA.
TUESDAY AND WEDNESDAY SHOULD BE DRY...WITH THE UPPER LEVEL RIDGE
IN PLACE OVER THE HIGH PLAINS AND LOW PRESSURE AT THE SURFACE OFF
TO THE WEST. WINDS WILL BE BREEZY FROM THE SOUTH BOTH
DAYS...HOWEVER ALL MODELS ARE IN AGREEMENT WITH KEEPING MOISTURE
LIMITED...WITH DEWPOINTS IN THE 40S AND 50S. THE LACK OF MOISTURE
ADVECTION LIKELY HAS SOMETHING TO DO WITH TROPICAL STORM ISAAC
/LIKELY HURRICANE ISAAC BY THIS TIME/ TAKING MUCH OF THE AVAILABLE
MOISTURE. TUESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK...WITH
MID TO UPPER 90S EXPECTED...WITH WIDESPREAD 90S FOR WEDNESDAY AS
WELL.
FIRE WEATHER CONCERNS WILL BE ON THE FOREFRONT MONDAY THROUGH
WEDNESDAY...WITH THE COMBINATION OF THE DRY AIR AND BREEZY WINDS.
ALTHOUGH THE CURRENT FORECAST WOULD KEEP CONDITIONS OUT OF
CRITICAL CRITERIA...THE EXTREME DRYNESS OF THE FUELS COULD CAUSE
THE NEED FOR RED FLAG WARNINGS IF CONDITIONS ARE EXPECTED TO BE
CLOSE.
LONG TERM...THURSDAY THROUGH SATURDAY
THE UPPER LEVEL RIDGE HOLDS STRONG THROUGH THE SECOND HALF OF THE
WEEK. THIS WILL KEEP TEMPERATURES WARM AND ABOVE NORMAL IN THE
90S...WITH LITTLE IF ANY CHANCES FOR RAIN. AS THE RIDGE SHIFTS
EAST...COULD GET PACIFIC MOISTURE TO PUSH INTO THE NORTHERN AND
CENTRAL PLAINS...HOWEVER MODELS ARE NOT INDICATING ANY UPPER LEVEL
SUPPORT FOR ANY SHOWER OR STORM DEVELOPMENT SO KEPT THE FORECAST
DRY. IN TURN...THE STRENGTH OF THE RIDGE WILL LIKELY KEEP ANY
MOISTURE FROM ISAAC WELL EAST OF THE PLAINS. THERE HAS BEEN
CONSIDERABLE DIFFERENCES IN WHERE THE SYSTEM WILL TRACK ONCE
COMING ON-SHORE BUT AGAIN BECAUSE OF THE RIDGE OVER THE
PLAINS...IT WILL PROBABLY MOVE NORTH INTO THE OHIO RIVER VALLEY OR
EVEN ALONG THE EAST COAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
708 AM CDT SUN AUG 26 2012
.AVIATION...
WIDESPREAD DENSE FOG OVER WESTERN AND NORTH CENTRAL NEBRASKA EAST
OF A KIML TO KANW LINE. KLBF ZERO VISIBILITY AND KBBW 1/4SM.
CEILINGS AND VISIBILITIES WILL IMPROVE THROUGH LATE MORNING. VFR
CONDITIONS THIS AFTERNOON. ISOLATED THUNDERSTORMS EXPECTED TO
DEVELOP IN THE NEBRASKA PANHANDLE LATE THIS AFTERNOON AND WILL
MOVE EAST INTO THE WESTERN NEBRASKA SANDHILLS THROUGH THE EARLY
EVENING BEFORE DISSIPATING. STRONG ERRATIC WINDS IN THE VICINITY
OF THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 631 AM CDT SUN AUG 26 2012/
UPDATE...
UPDATED TO INCLUDE EXPANDING DENSE FOG CONDITIONS.
PREV DISCUSSION... /ISSUED 339 AM CDT SUN AUG 26 2012/
SHORT TERM...TODAY THROUGH WEDNESDAY
PRIMARY CONCERNS FOR THE FORECAST ARE THUNDERSTORM CHANCES THIS
AFTERNOON AND EVENING AND AGAIN MONDAY EVENING...AS WELL AS
TEMPERATURES. ALSO KEEPING AN EYE ON FIRE CONCERNS THROUGH THE
FIRST HALF OF THE WEEK.
WATER VAPOR IMAGERY THIS MORNING WAS SHOWING THE UPPER LEVEL
SHORTWAVE TROUGH WHICH PUSHED THE COLD FRONT ACROSS THE FORECAST
AREA ON SATURDAY LOCATED FROM CENTRAL KANSAS INTO WISCONSIN.
THE FRONT HAD STALLED OUT JUST TO THE EAST OF THE FORECAST AREA
AND HAD SINCE WASHED OUT...WITH HIGH PRESSURE NOW CENTERED OVER
WESTERN NEBRASKA. THE DEWPOINT GRADIENT REMAINS...WITH MOIST AIR
OVER EASTERN NEBRASKA /60 DEGREE DEWPOINTS ALONG AND EAST OF A KMCK
TO KBBW TO KONL LINE/...WITH VALUES IN THE 30S OVER THE NORTHERN
PANHANDLE. THUNDERSTORMS WERE ONGOING AHEAD OF THE SYSTEM...INTO
IOWA AND MISSOURI...WHILE STRATUS AND FOG WERE OBSERVED ACROSS
MUCH OF EASTERN NEBRASKA.
ONCE AGAIN LOOKING AT THE LARGE SCALE FLOW...THE UPPER LEVEL RIDGE
WAS CENTERED OVER THE SOUTHERN ROCKY MOUNTAIN RANGE. ALSO OF
NOTE...TROPICAL STORM ISAAC REMAINS A FOCAL POINT WITH THE CENTER
CURRENTLY MOVING OVER CUBA.
THE LOCAL FORECAST AREA IS RIGHT ON THE EDGE OF THE LOW LEVEL
MOISTURE AND FOG THIS MORNING. THE RAP SEEMS TO HAVE A GOOD HANDLE
ON THIS MOISTURE AND SHOWS IT DISSIPATING BY 16Z. WITH THE
PLACEMENT OF THE MOISTURE...AND THAT THE MODELS ARE PUSHING THE
SURFACE LOW INTO THE PANHANDLE TO TIGHTEN THE PRESSURE GRADIENT
AND INCREASE THE WIND...THIS SEEMS LIKE A GOOD SOLUTION AND WILL
FOLLOW THIS LEAD INTO THE FORECAST FOR TODAY. WITH THE EARLY
DISMISSAL OF THE CLOUDS...AND RETURN FLOW...WOULD EXPECT STRONG
WARMING TODAY. TEMPERATURES DO WARM A FEW DEGREES ALOFT FROM WHAT
WAS OBSERVED ON SATURDAY...ALTHOUGH SOUNDINGS ARE INDICATING FULL
MIXING WON/T BE REALIZED. HOWEVER WITH THE EXTRA HOURS OF
SUNSHINE...BELIEVE 90S ARE ATTAINABLE FOR TODAY IN MOST LOCATIONS.
AN UPPER LEVEL SHORTWAVE TROUGH WAS OBSERVED EARLY THIS MORNING
MOVING INTO WYOMING. THIS ENERGY WILL BE THE FOCUS FOR
THUNDERSTORM DEVELOPMENT LATER TODAY. ALTHOUGH THE RETURN FLOW
DOESN/T LOOK PARTICULARLY STRONG UNTIL LATER THIS EVENING...BOTH
THE NAM AND GFS INCREASE PRECIPITABLE WATER TO VALUES OF AN INCH
OR MORE /120 PERCENT OF NORMAL/ OVER THE PANHANDLE /JUST FOR
REFERENCE THE 26.00Z LBF SOUNDING OBSERVED PW OF 0.67...WHILE RAP
HAD 0.43/. EVEN IF THE MOISTURE DOESN/T INCREASE THIS MUCH...THERE
SHOULD BE ENOUGH TO ALLOW FOR ISOLATED THUNDERSTORMS TO DEVELOP
OVER THE PANHANDLE LATER THIS AFTERNOON. SOUNDINGS SHOWING
INVERTED-V PROFILE SO WILL CONTINUE TO SEE THE THREATS FOR STRONG
AND ERRATIC WINDS FROM ANY STORMS...AS WELL AS LOW RAINFALL
AMOUNTS AND A CHANCE FOR SOME STRAY DRY LIGHTNING STRIKES. GOING
EASTWARD...MOISTURE INCREASE ISN/T AS SUBSTANTIAL...AND WITH LARGE
SCALE FORCING BEING LESS...THESE AREAS WILL STAY CAPPED SO WILL
KEEP AREAS EAST OF A LINE FROM NORTH PLATTE TO AINSWORTH DRY.
MONDAY WILL BE A SIMILAR DAY TO SUNDAY...WITH STRONG WARMING
EXPECTED WITH LOTS OF SUNSHINE AND HIGHS IN THE 90S. ALTHOUGH THE
RIDGE WILL BUILD INTO THE PLAINS THROUGH THE DAY...A DECENT
SHORTWAVE TROUGH IS SIGNALED TO PUSH OVER THE RIDGE AND INTO
NEBRASKA IN THE AFTERNOON. THIS SIGNAL WAS BEING PICKED UP BY THE
ECMWF/NAM/GEM-REGIONAL/SREF...AND WITH THE PROPER PLACEMENT OF THE
RIDGE...FELT IT WAS FITTING TO ADD A SLIGHT CHANCE OVER TH
PANHANDLE AND FAR NORTHWEST NEBRASKA.
TUESDAY AND WEDNESDAY SHOULD BE DRY...WITH THE UPPER LEVEL RIDGE
IN PLACE OVER THE HIGH PLAINS AND LOW PRESSURE AT THE SURFACE OFF
TO THE WEST. WINDS WILL BE BREEZY FROM THE SOUTH BOTH
DAYS...HOWEVER ALL MODELS ARE IN AGREEMENT WITH KEEPING MOISTURE
LIMITED...WITH DEWPOINTS IN THE 40S AND 50S. THE LACK OF MOISTURE
ADVECTION LIKELY HAS SOMETHING TO DO WITH TROPICAL STORM ISAAC
/LIKELY HURRICANE ISAAC BY THIS TIME/ TAKING MUCH OF THE AVAILABLE
MOISTURE. TUESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK...WITH
MID TO UPPER 90S EXPECTED...WITH WIDESPREAD 90S FOR WEDNESDAY AS
WELL.
FIRE WEATHER CONCERNS WILL BE ON THE FOREFRONT MONDAY THROUGH
WEDNESDAY...WITH THE COMBINATION OF THE DRY AIR AND BREEZY WINDS.
ALTHOUGH THE CURRENT FORECAST WOULD KEEP CONDITIONS OUT OF
CRITICAL CRITERIA...THE EXTREME DRYNESS OF THE FUELS COULD CAUSE
THE NEED FOR RED FLAG WARNINGS IF CONDITIONS ARE EXPECTED TO BE
CLOSE.
LONG TERM...THURSDAY THROUGH SATURDAY
THE UPPER LEVEL RIDGE HOLDS STRONG THROUGH THE SECOND HALF OF THE
WEEK. THIS WILL KEEP TEMPERATURES WARM AND ABOVE NORMAL IN THE
90S...WITH LITTLE IF ANY CHANCES FOR RAIN. AS THE RIDGE SHIFTS
EAST...COULD GET PACIFIC MOISTURE TO PUSH INTO THE NORTHERN AND
CENTRAL PLAINS...HOWEVER MODELS ARE NOT INDICATING ANY UPPER LEVEL
SUPPORT FOR ANY SHOWER OR STORM DEVELOPMENT SO KEPT THE FORECAST
DRY. IN TURN...THE STRENGTH OF THE RIDGE WILL LIKELY KEEP ANY
MOISTURE FROM ISAAC WELL EAST OF THE PLAINS. THERE HAS BEEN
CONSIDERABLE DIFFERENCES IN WHERE THE SYSTEM WILL TRACK ONCE
COMING ON-SHORE BUT AGAIN BECAUSE OF THE RIDGE OVER THE
PLAINS...IT WILL PROBABLY MOVE NORTH INTO THE OHIO RIVER VALLEY OR
EVEN ALONG THE EAST COAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...DENSE FOG ADVISORY UNTIL 10 AM CDT
THIS MORNING FOR NEZ007-009-010-026>029-037-038-059-070-071.
&&
$$
SHORT TERM/EXTENDED...POWER/BROOKS
AVIATION...POWER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
631 AM CDT SUN AUG 26 2012
.UPDATE...
UPDATED TO INCLUDE EXPANDING DENSE FOG CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 339 AM CDT SUN AUG 26 2012/
SHORT TERM...TODAY THROUGH WEDNESDAY
PRIMARY CONCERNS FOR THE FORECAST ARE THUNDERSTORM CHANCES THIS
AFTERNOON AND EVENING AND AGAIN MONDAY EVENING...AS WELL AS
TEMPERATURES. ALSO KEEPING AN EYE ON FIRE CONCERNS THROUGH THE
FIRST HALF OF THE WEEK.
WATER VAPOR IMAGERY THIS MORNING WAS SHOWING THE UPPER LEVEL
SHORTWAVE TROUGH WHICH PUSHED THE COLD FRONT ACROSS THE FORECAST
AREA ON SATURDAY LOCATED FROM CENTRAL KANSAS INTO WISCONSIN.
THE FRONT HAD STALLED OUT JUST TO THE EAST OF THE FORECAST AREA
AND HAD SINCE WASHED OUT...WITH HIGH PRESSURE NOW CENTERED OVER
WESTERN NEBRASKA. THE DEWPOINT GRADIENT REMAINS...WITH MOIST AIR
OVER EASTERN NEBRASKA /60 DEGREE DEWPOINTS ALONG AND EAST OF A KMCK
TO KBBW TO KONL LINE/...WITH VALUES IN THE 30S OVER THE NORTHERN
PANHANDLE. THUNDERSTORMS WERE ONGOING AHEAD OF THE SYSTEM...INTO
IOWA AND MISSOURI...WHILE STRATUS AND FOG WERE OBSERVED ACROSS
MUCH OF EASTERN NEBRASKA.
ONCE AGAIN LOOKING AT THE LARGE SCALE FLOW...THE UPPER LEVEL RIDGE
WAS CENTERED OVER THE SOUTHERN ROCKY MOUNTAIN RANGE. ALSO OF
NOTE...TROPICAL STORM ISAAC REMAINS A FOCAL POINT WITH THE CENTER
CURRENTLY MOVING OVER CUBA.
THE LOCAL FORECAST AREA IS RIGHT ON THE EDGE OF THE LOW LEVEL
MOISTURE AND FOG THIS MORNING. THE RAP SEEMS TO HAVE A GOOD HANDLE
ON THIS MOISTURE AND SHOWS IT DISSIPATING BY 16Z. WITH THE
PLACEMENT OF THE MOISTURE...AND THAT THE MODELS ARE PUSHING THE
SURFACE LOW INTO THE PANHANDLE TO TIGHTEN THE PRESSURE GRADIENT
AND INCREASE THE WIND...THIS SEEMS LIKE A GOOD SOLUTION AND WILL
FOLLOW THIS LEAD INTO THE FORECAST FOR TODAY. WITH THE EARLY
DISMISSAL OF THE CLOUDS...AND RETURN FLOW...WOULD EXPECT STRONG
WARMING TODAY. TEMPERATURES DO WARM A FEW DEGREES ALOFT FROM WHAT
WAS OBSERVED ON SATURDAY...ALTHOUGH SOUNDINGS ARE INDICATING FULL
MIXING WON/T BE REALIZED. HOWEVER WITH THE EXTRA HOURS OF
SUNSHINE...BELIEVE 90S ARE ATTAINABLE FOR TODAY IN MOST LOCATIONS.
AN UPPER LEVEL SHORTWAVE TROUGH WAS OBSERVED EARLY THIS MORNING
MOVING INTO WYOMING. THIS ENERGY WILL BE THE FOCUS FOR
THUNDERSTORM DEVELOPMENT LATER TODAY. ALTHOUGH THE RETURN FLOW
DOESN/T LOOK PARTICULARLY STRONG UNTIL LATER THIS EVENING...BOTH
THE NAM AND GFS INCREASE PRECIPITABLE WATER TO VALUES OF AN INCH
OR MORE /120 PERCENT OF NORMAL/ OVER THE PANHANDLE /JUST FOR
REFERENCE THE 26.00Z LBF SOUNDING OBSERVED PW OF 0.67...WHILE RAP
HAD 0.43/. EVEN IF THE MOISTURE DOESN/T INCREASE THIS MUCH...THERE
SHOULD BE ENOUGH TO ALLOW FOR ISOLATED THUNDERSTORMS TO DEVELOP
OVER THE PANHANDLE LATER THIS AFTERNOON. SOUNDINGS SHOWING
INVERTED-V PROFILE SO WILL CONTINUE TO SEE THE THREATS FOR STRONG
AND ERRATIC WINDS FROM ANY STORMS...AS WELL AS LOW RAINFALL
AMOUNTS AND A CHANCE FOR SOME STRAY DRY LIGHTNING STRIKES. GOING
EASTWARD...MOISTURE INCREASE ISN/T AS SUBSTANTIAL...AND WITH LARGE
SCALE FORCING BEING LESS...THESE AREAS WILL STAY CAPPED SO WILL
KEEP AREAS EAST OF A LINE FROM NORTH PLATTE TO AINSWORTH DRY.
MONDAY WILL BE A SIMILAR DAY TO SUNDAY...WITH STRONG WARMING
EXPECTED WITH LOTS OF SUNSHINE AND HIGHS IN THE 90S. ALTHOUGH THE
RIDGE WILL BUILD INTO THE PLAINS THROUGH THE DAY...A DECENT
SHORTWAVE TROUGH IS SIGNALED TO PUSH OVER THE RIDGE AND INTO
NEBRASKA IN THE AFTERNOON. THIS SIGNAL WAS BEING PICKED UP BY THE
ECMWF/NAM/GEM-REGIONAL/SREF...AND WITH THE PROPER PLACEMENT OF THE
RIDGE...FELT IT WAS FITTING TO ADD A SLIGHT CHANCE OVER TH
PANHANDLE AND FAR NORTHWEST NEBRASKA.
TUESDAY AND WEDNESDAY SHOULD BE DRY...WITH THE UPPER LEVEL RIDGE
IN PLACE OVER THE HIGH PLAINS AND LOW PRESSURE AT THE SURFACE OFF
TO THE WEST. WINDS WILL BE BREEZY FROM THE SOUTH BOTH
DAYS...HOWEVER ALL MODELS ARE IN AGREEMENT WITH KEEPING MOISTURE
LIMITED...WITH DEWPOINTS IN THE 40S AND 50S. THE LACK OF MOISTURE
ADVECTION LIKELY HAS SOMETHING TO DO WITH TROPICAL STORM ISAAC
/LIKELY HURRICANE ISAAC BY THIS TIME/ TAKING MUCH OF THE AVAILABLE
MOISTURE. TUESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK...WITH
MID TO UPPER 90S EXPECTED...WITH WIDESPREAD 90S FOR WEDNESDAY AS
WELL.
FIRE WEATHER CONCERNS WILL BE ON THE FOREFRONT MONDAY THROUGH
WEDNESDAY...WITH THE COMBINATION OF THE DRY AIR AND BREEZY WINDS.
ALTHOUGH THE CURRENT FORECAST WOULD KEEP CONDITIONS OUT OF
CRITICAL CRITERIA...THE EXTREME DRYNESS OF THE FUELS COULD CAUSE
THE NEED FOR RED FLAG WARNINGS IF CONDITIONS ARE EXPECTED TO BE
CLOSE.
LONG TERM...THURSDAY THROUGH SATURDAY
THE UPPER LEVEL RIDGE HOLDS STRONG THROUGH THE SECOND HALF OF THE
WEEK. THIS WILL KEEP TEMPERATURES WARM AND ABOVE NORMAL IN THE
90S...WITH LITTLE IF ANY CHANCES FOR RAIN. AS THE RIDGE SHIFTS
EAST...COULD GET PACIFIC MOISTURE TO PUSH INTO THE NORTHERN AND
CENTRAL PLAINS...HOWEVER MODELS ARE NOT INDICATING ANY UPPER LEVEL
SUPPORT FOR ANY SHOWER OR STORM DEVELOPMENT SO KEPT THE FORECAST
DRY. IN TURN...THE STRENGTH OF THE RIDGE WILL LIKELY KEEP ANY
MOISTURE FROM ISAAC WELL EAST OF THE PLAINS. THERE HAS BEEN
CONSIDERABLE DIFFERENCES IN WHERE THE SYSTEM WILL TRACK ONCE
COMING ON-SHORE BUT AGAIN BECAUSE OF THE RIDGE OVER THE
PLAINS...IT WILL PROBABLY MOVE NORTH INTO THE OHIO RIVER VALLEY OR
EVEN ALONG THE EAST COAST.
AVIATION...
SOME PATCHY FOG DEVELOPING OVER NORTH CENTRAL NEBRASKA EARLY THIS
MORNING. MAIN AREA OF CONCERN WILL BE FROM KBBW TO KONL BUT
VISIBILITIES ALONG THE PLATTE RIVER VALLEY MAY BE REDUCED TO MVFR
AROUND SUNRISE. SOME ISOLATED THUNDERSTORMS MAY DEVELOP OVER THE
NEBRASKA PANHANDLE AND MOVE INTO THE WESTERN NEBRASKA SANDHILLS THIS
EVENING. ACTIVITY WILL STAY TO THE WEST OF A LINE FROM KVTN TO KLBF.
STRONG ERRATIC WINDS CAN BE EXPECTED IN THE VICINITY OF
THUNDERSTORMS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...DENSE FOG ADVISORY UNTIL 10 AM CDT
THIS MORNING FOR NEZ007-009-010-026>029-037-038-059-070-071.
&&
$$
SHORT TERM/EXTENDED...POWER/BROOKS
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
339 AM CDT SUN AUG 26 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
PRIMARY CONCERNS FOR THE FORECAST ARE THUNDERSTORM CHANCES THIS
AFTERNOON AND EVENING AND AGAIN MONDAY EVENING...AS WELL AS
TEMPERATURES. ALSO KEEPING AN EYE ON FIRE CONCERNS THROUGH THE
FIRST HALF OF THE WEEK.
WATER VAPOR IMAGERY THIS MORNING WAS SHOWING THE UPPER LEVEL
SHORTWAVE TROUGH WHICH PUSHED THE COLD FRONT ACROSS THE FORECAST
AREA ON SATURDAY LOCATED FROM CENTRAL KANSAS INTO WISCONSIN.
THE FRONT HAD STALLED OUT JUST TO THE EAST OF THE FORECAST AREA
AND HAD SINCE WASHED OUT...WITH HIGH PRESSURE NOW CENTERED OVER
WESTERN NEBRASKA. THE DEWPOINT GRADIENT REMAINS...WITH MOIST AIR
OVER EASTERN NEBRASKA /60 DEGREE DEWPOINTS ALONG AND EAST OF A KMCK
TO KBBW TO KONL LINE/...WITH VALUES IN THE 30S OVER THE NORTHERN
PANHANDLE. THUNDERSTORMS WERE ONGOING AHEAD OF THE SYSTEM...INTO
IOWA AND MISSOURI...WHILE STRATUS AND FOG WERE OBSERVED ACROSS
MUCH OF EASTERN NEBRASKA.
ONCE AGAIN LOOKING AT THE LARGE SCALE FLOW...THE UPPER LEVEL RIDGE
WAS CENTERED OVER THE SOUTHERN ROCKY MOUNTAIN RANGE. ALSO OF
NOTE...TROPICAL STORM ISAAC REMAINS A FOCAL POINT WITH THE CENTER
CURRENTLY MOVING OVER CUBA.
THE LOCAL FORECAST AREA IS RIGHT ON THE EDGE OF THE LOW LEVEL
MOISTURE AND FOG THIS MORNING. THE RAP SEEMS TO HAVE A GOOD HANDLE
ON THIS MOISTURE AND SHOWS IT DISSIPATING BY 16Z. WITH THE
PLACEMENT OF THE MOISTURE...AND THAT THE MODELS ARE PUSHING THE
SURFACE LOW INTO THE PANHANDLE TO TIGHTEN THE PRESSURE GRADIENT
AND INCREASE THE WIND...THIS SEEMS LIKE A GOOD SOLUTION AND WILL
FOLLOW THIS LEAD INTO THE FORECAST FOR TODAY. WITH THE EARLY
DISMISSAL OF THE CLOUDS...AND RETURN FLOW...WOULD EXPECT STRONG
WARMING TODAY. TEMPERATURES DO WARM A FEW DEGREES ALOFT FROM WHAT
WAS OBSERVED ON SATURDAY...ALTHOUGH SOUNDINGS ARE INDICATING FULL
MIXING WON/T BE REALIZED. HOWEVER WITH THE EXTRA HOURS OF
SUNSHINE...BELIEVE 90S ARE ATTAINABLE FOR TODAY IN MOST LOCATIONS.
AN UPPER LEVEL SHORTWAVE TROUGH WAS OBSERVED EARLY THIS MORNING
MOVING INTO WYOMING. THIS ENERGY WILL BE THE FOCUS FOR
THUNDERSTORM DEVELOPMENT LATER TODAY. ALTHOUGH THE RETURN FLOW
DOESN/T LOOK PARTICULARLY STRONG UNTIL LATER THIS EVENING...BOTH
THE NAM AND GFS INCREASE PRECIPITABLE WATER TO VALUES OF AN INCH
OR MORE /120 PERCENT OF NORMAL/ OVER THE PANHANDLE /JUST FOR
REFERENCE THE 26.00Z LBF SOUNDING OBSERVED PW OF 0.67...WHILE RAP
HAD 0.43/. EVEN IF THE MOISTURE DOESN/T INCREASE THIS MUCH...THERE
SHOULD BE ENOUGH TO ALLOW FOR ISOLATED THUNDERSTORMS TO DEVELOP
OVER THE PANHANDLE LATER THIS AFTERNOON. SOUNDINGS SHOWING
INVERTED-V PROFILE SO WILL CONTINUE TO SEE THE THREATS FOR STRONG
AND ERRATIC WINDS FROM ANY STORMS...AS WELL AS LOW RAINFALL
AMOUNTS AND A CHANCE FOR SOME STRAY DRY LIGHTNING STRIKES. GOING
EASTWARD...MOISTURE INCREASE ISN/T AS SUBSTANTIAL...AND WITH LARGE
SCALE FORCING BEING LESS...THESE AREAS WILL STAY CAPPED SO WILL
KEEP AREAS EAST OF A LINE FROM NORTH PLATTE TO AINSWORTH DRY.
MONDAY WILL BE A SIMILAR DAY TO SUNDAY...WITH STRONG WARMING
EXPECTED WITH LOTS OF SUNSHINE AND HIGHS IN THE 90S. ALTHOUGH THE
RIDGE WILL BUILD INTO THE PLAINS THROUGH THE DAY...A DECENT
SHORTWAVE TROUGH IS SIGNALED TO PUSH OVER THE RIDGE AND INTO
NEBRASKA IN THE AFTERNOON. THIS SIGNAL WAS BEING PICKED UP BY THE
ECMWF/NAM/GEM-REGIONAL/SREF...AND WITH THE PROPER PLACEMENT OF THE
RIDGE...FELT IT WAS FITTING TO ADD A SLIGHT CHANCE OVER TH
PANHANDLE AND FAR NORTHWEST NEBRASKA.
TUESDAY AND WEDNESDAY SHOULD BE DRY...WITH THE UPPER LEVEL RIDGE
IN PLACE OVER THE HIGH PLAINS AND LOW PRESSURE AT THE SURFACE OFF
TO THE WEST. WINDS WILL BE BREEZY FROM THE SOUTH BOTH
DAYS...HOWEVER ALL MODELS ARE IN AGREEMENT WITH KEEPING MOISTURE
LIMITED...WITH DEWPOINTS IN THE 40S AND 50S. THE LACK OF MOISTURE
ADVECTION LIKELY HAS SOMETHING TO DO WITH TROPICAL STORM ISAAC
/LIKELY HURRICANE ISAAC BY THIS TIME/ TAKING MUCH OF THE AVAILABLE
MOISTURE. TUESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK...WITH
MID TO UPPER 90S EXPECTED...WITH WIDESPREAD 90S FOR WEDNESDAY AS
WELL.
FIRE WEATHER CONCERNS WILL BE ON THE FOREFRONT MONDAY THROUGH
WEDNESDAY...WITH THE COMBINATION OF THE DRY AIR AND BREEZY WINDS.
ALTHOUGH THE CURRENT FORECAST WOULD KEEP CONDITIONS OUT OF
CRITICAL CRITERIA...THE EXTREME DRYNESS OF THE FUELS COULD CAUSE
THE NEED FOR RED FLAG WARNINGS IF CONDITIONS ARE EXPECTED TO BE
CLOSE.
.LONG TERM...THURSDAY THROUGH SATURDAY
THE UPPER LEVEL RIDGE HOLDS STRONG THROUGH THE SECOND HALF OF THE
WEEK. THIS WILL KEEP TEMPERATURES WARM AND ABOVE NORMAL IN THE
90S...WITH LITTLE IF ANY CHANCES FOR RAIN. AS THE RIDGE SHIFTS
EAST...COULD GET PACIFIC MOISTURE TO PUSH INTO THE NORTHERN AND
CENTRAL PLAINS...HOWEVER MODELS ARE NOT INDICATING ANY UPPER LEVEL
SUPPORT FOR ANY SHOWER OR STORM DEVELOPMENT SO KEPT THE FORECAST
DRY. IN TURN...THE STRENGTH OF THE RIDGE WILL LIKELY KEEP ANY
MOISTURE FROM ISAAC WELL EAST OF THE PLAINS. THERE HAS BEEN
CONSIDERABLE DIFFERENCES IN WHERE THE SYSTEM WILL TRACK ONCE
COMING ON-SHORE BUT AGAIN BECAUSE OF THE RIDGE OVER THE
PLAINS...IT WILL PROBABLY MOVE NORTH INTO THE OHIO RIVER VALLEY OR
EVEN ALONG THE EAST COAST.
&&
.AVIATION...
SOME PATCHY FOG DEVELOPING OVER NORTH CENTRAL NEBRASKA EARLY THIS
MORNING. MAIN AREA OF CONCERN WILL BE FROM KBBW TO KONL BUT
VISIBILITIES ALONG THE PLATTE RIVER VALLEY MAY BE REDUCED TO MVFR
AROUND SUNRISE. SOME ISOLATED THUNDERSTORMS MAY DEVELOP OVER THE
NEBRASKA PANHANDLE AND MOVE INTO THE WESTERN NEBRASKA SANDHILLS THIS
EVENING. ACTIVITY WILL STAY TO THE WEST OF A LINE FROM KVTN TO KLBF.
STRONG ERRATIC WINDS CAN BE EXPECTED IN THE VICINITY OF
THUNDERSTORMS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS BUFFALO NY
220 PM EDT SUN AUG 26 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING ONE LAST VERY WARM DAY TODAY...WITH
INCREASING CLOUDS AND A SLIGHT CHANCE OF SHOWERS IN THE AFTERNOON.
THE CHANCE FOR SHOWERS WILL INCREASE FURTHER ON MONDAY AND MONDAY
NIGHT AS A COLD FRONT CROSSES THE REGION. A RETURN TO SEASONABLY
NORMAL TEMPERATURES AND DRY WEATHER IS EXPECTED FOR THE MIDDLE
PORTION OF THE COMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MINOR CHANGES TO THE GRIDS...OTHERWISE FORECAST REMAINS ON TRACK.
PREVIOUS DISCUSSION FOLLOWS BELOW.
SURFACE HIGH PRESSURE IS CENTERED JUST OFF THE NEW ENGLAND COAST
WITH RIDGING EXTENDING BACK ACROSS NY INTO THE EASTERN OHIO VALLEY
THIS MORNING. ALOFT A CUT OFF LOW IS CYCLONICALLY SPINNING OVER THE
VIRGINIAS WITH SOME CONVECTION ACROSS THE DELMARVA. SATELLITE SHOWS
SOME SLOW SHIFT OF MID LAYER CLOUDS NORTHWARD INTO CENTRAL NY AND
THE INTERIOR SOUTHERN TIER.
LOOK FOR INCREASING CLOUDS THROUGH TODAY AS THE CUTOFF LOW CONTINUES TO
DRIFT NORTH. THE INCREASE IN CLOUD COVER AND SLIGHTLY COOLER
TEMPERATURES ALOFT ADVECTING INTO THE REGION ASSOCIATED WITH THE LOW
SHOULD YIELD COOLER TEMPERATURES...PARTICULARLY ACROSS THE SOUTHERN
TIER WHERE HIGHS SHOULD TOP OUT IN THE MID TO UPPER 70S. AREAS
FARTHER NORTH IN THE NIAGARA FRONTIER WILL LIKELY SEE ENOUGH
SUNSHINE TO CLIMB INTO THE LOW TO MID 80S AND THE WARMEST READINGS
WILL BE FOUND ACROSS THE NORTH COUNTRY WHERE SKIES SHOULD REMAIN
MOSTLY SUNNY THROUGHOUT THE DAY.
INCREASING LOW LEVEL MOISTURE WITH DEWPOINTS CREEPING BACK INTO THE
LOWER 60S AND NOMINAL COOLING ALOFT MAY BE JUST ENOUGH TO TRIGGER A
FEW SHOWERS...MAINLY ACROSS AREAS WEST OF THE GENESEE
VALLEY...HOWEVER GIVEN THE AMOUNT OF LINGERING DRY AIR...WIDESPREAD
CONVECTION IS NOT EXPECTED. THE 07Z RUN OF THE HRRR SHOWS SOME
SHOWERS POSSIBLE AROUND 20Z.
TONIGHT...ANY DIURNAL SHOWERS ACROSS WNY SHOULD END WITH HIGH
PRESSURE REMAINING OVER THE AREA. A COLD FRONT WILL CONTINUE TO
PRESS EAST TOWARD THE FORECAST AREA FROM MICHIGAN. CLOUD COVER WILL
INCREASING TOWARD OVERCAST WITH TEMPERATURES OVERNIGHT FALLING ONLY
INTO THE 60S...ON THE WARM SIDE WITH HIGHER HUMIDITY AROUND. FOG
WILL AGAIN BE LIMITED DUE TO WINDS NOT LOWERING TO CALM OVERNIGHT
AHEAD OF A COLD FRONT JUST TO THE WEST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
FOCUS IN THE SHORT TERM PERIOD WILL BE ON A COLD FRONTAL PASSAGE ON
MONDAY AND ASSOCIATED RAIN CHANCES. THERE REMAINS SOME TIMING
DIFFERENCES WITH THE GFS A GOOD 6 HOURS FASTER THAN THE NAM. THE
SLOWER NAM SOLUTION HAS SOME SUPPORT FROM THE CANADIAN GEM AND SREF
ENSEMBLE MEAN. WITH A WEAK DECAYING CLOSED LOW OVER THE MID ATLANTIC
LIKELY PROVING TO BE A ROADBLOCK TO UPSTREAM SYSTEMS...HAVE FAVORED
THE SLOWER NAM TIMING. WITH THIS IN MIND THE BULK OF THE AREA WILL
BE RAIN FREE MONDAY MORNING WITH INCREASING CLOUDS.
LATER IN THE DAY MODEST MID LEVEL HEIGHT FALLS AND PVA WILL APPROACH
THE REGION...WITH THE ASSOCIATED COLD FRONT ENTERING WESTERN NY BY
LATE AFTERNOON OR EVENING...THEN SWEEPING ACROSS THE REST OF THE
AREA MONDAY NIGHT. A 70+ KNOT UPPER LEVEL JET WILL ALSO PROVIDE SOME
UPPER LEVEL DIVERGENCE AS THE RIGHT ENTRANCE REGION BECOMES SITUATED
OVER THE LOWER LAKES MONDAY AFTERNOON. SEVERAL DAYS OF SOUTHERLY
FLOW AHEAD OF THIS SYSTEM WILL PROVIDE A DECENT MOISTURE RETURN...
WITH PWAT OF AROUND 1.5 INCHES AND SURFACE DEWPOINTS IN THE MID 60S
ON AVERAGE. WITH THIS MOISTURE AND FORCING COMING INTO PLAY...HAVE
INCREASED POPS TO LIKELY FOR THE FRONTAL PASSAGE. THE TIMING OF THE
MOST WIDESPREAD PRECIP WILL BE LATE AFTERNOON AND EARLY EVENING IN
WESTERN NY...AND MAINLY MONDAY EVENING AND NIGHT FROM THE GENESEE
VALLEY EAST INTO CENTRAL AND NORTHERN NY.
INSTABILITY WILL ONLY BE MARGINAL GIVEN THE VERY WARM TEMPS
ALOFT...WITH SBCAPE OF ONLY 500-1000J/KG. A TALL/SKINNY CAPE PROFILE
AND ADEQUATE MOISTURE SUGGEST POTENTIAL FOR LOCAL HEAVY DOWNPOURS
WITH ANY STORMS THAT FORM. THE WEAK INSTABILITY AND RELATIVELY WEAK
WIND FIELDS WILL KEEP STORMS POORLY ORGANIZED WITH LITTLE POTENTIAL
FOR ANY WIND OR HAIL. MONDAY WILL STILL BE QUITE WARM WITH 850MB
TEMPS OF AROUND +15C. WITH THE EXPECTATION THAT RAIN WILL HOLD OFF
UNTIL THE AFTERNOON...HAVE GONE ABOVE ALL MODEL GUIDANCE WITH HIGHS
IN THE MID 80S IN MANY LOCATIONS...ALONG WITH INCREASED HUMIDITY.
THE COLD FRONT AND ASSOCIATED RAIN WILL BE EAST OF THE CWA BY
DAYBREAK TUESDAY. A SECONDARY COLD FRONT AND ASSOCIATED MID LEVEL
SHORTWAVE WILL DROP INTO THE NORTH COUNTRY DURING THE DAY TUESDAY
AND MAY TOUCH OFF A FEW MORE WIDELY SCATTERED LIGHT SHOWERS. SOME
LIMITED MOISTURE ALONG AND AHEAD OF THIS SECONDARY TROUGH WILL ALSO
PRODUCE SOME DIURNAL CUMULUS...WITH A MIX OF SUN AND CLOUDS IN MANY
LOCATIONS. A SOMEWHAT COOLER AIRMASS WILL BUILD INTO THE AREA WITH
TEMPERATURES DROPPING BACK CLOSER TO AVERAGE. EXPECT HIGHS IN THE
MID TO UPPER 70S IN MOST LOCATIONS.
TUESDAY EVENING THE SECONDARY COLD FRONT WILL DROP SOUTH ACROSS THE
AREA WITH A PERIOD OF CLOUD COVER...FOLLOWED BY CLEARING SKIES
OVERNIGHT AND ADDITIONAL COLD AIR ADVECTION. THIS WILL ALLOW TEMPS
TO DROP INTO THE MID 50S ON THE LAKE PLAINS AND AROUND 50 IN THE
COOLER SOUTHERN TIER VALLEYS AND TUG HILL REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ON WEDNESDAY A LONGWAVE TROUGH WILL BECOME ESTABLISHED ACROSS
SOUTHEAST CANADA WITH A NORTHWEST FLOW OF COOLER AIR DIRECTED INTO
THE GREAT LAKES. SURFACE HIGH PRESSURE WILL BUILD INTO THE OHIO
VALLEY AND GREAT LAKES WITH A RETURN TO SUNSHINE. 850MB TEMPS OF
ONLY AROUND +8C WILL SUPPORT HIGHS IN THE MID 70S ACROSS LOWER
ELEVATIONS AND AROUND 70 ACROSS HIGHER TERRAIN. HIGH PRESSURE
OVERHEAD WEDNESDAY NIGHT WILL PROVIDE CLEAR SKIES AND A SEASONABLY
COOL NIGHT WITH MID 50S ON THE LAKE PLAINS AND A FEW UPPER 40S IN
THE COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE ONTARIO.
BY THURSDAY AND FRIDAY HIGH PRESSURE WILL BUILD QUICKLY TO THE EAST
COAST AND ALLOW SOUTHWEST RETURN FLOW TO INCREASE. 850MB TEMPS RISE
TO AROUND +14C THURSDAY AFTERNOON ON THE LATEST ECMWF...A LITTLE
WARMER EVEN ON THE GFS. IF THE TIMING HOLDS THIS WILL SUPPORT HIGHS
IN THE LOW TO MID 80S. BY FRIDAY A CENTRAL PLAINS ELEVATED MIXED
LAYER /EML/ PLUME BECOMES CAPTURED BY THE NEXT SYSTEM AND IS
ADVECTED EAST ALL THE WAY INTO THE LOWER LAKES WITH 850MB TEMPS
SOARING TO AROUND +20C. IF THIS VERIFIES...TEMPERATURES WILL MAKE IT
INTO THE 90S ONCE AGAIN WITH HEAT RETURNING. BOTH DAYS WILL BE DRY
AS AN UPPER LEVEL RIDGE SHIFTS EAST ACROSS THE PLAINS AND INTO THE
OHIO VALLEY AND GREAT LAKES.
BY SATURDAY FORECAST UNCERTAINTY INCREASES WITH RESPECT TO THE
TIMING AND PLACEMENT OF THE REMNANTS OF ISAAC. THE LATEST GFS
SPREADS SOME RAIN TOWARDS THE NY/PA BORDER...WHILE THE ECMWF KEEPS
THE SYSTEM CUTOFF AND WELL SOUTH OF THE AREA. PREVIOUS FORECAST HAD
SOME LOW CHANCE POPS AND WILL KEEP THOSE FOR NOW. THE FORECAST FOR
NEXT WEEKEND WILL BE UNCERTAIN FOR SEVERAL DAYS TO COME UNTIL MODEL
GUIDANCE COMES INTO BETTER AGREEMENT WITH THE TRACK OF ISAAC...AND
ITS EVENTUAL INTERACTION WITH THE MID LATITUDE WESTERLIES.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
MOISTURE FROM THE UPPER LOW OVER MD/VA COMBINED WITH DAYTIME HEATING
HAS ALLOWED LOW/MID LEVEL CLOUDS TO DEVELOP AND SPREAD ACROSS
WESTERN NY THIS AFTERNOON. EVEN A FEW SHOWERS HAVE POPPED UP ACROSS
THE REGION, PRIMARILY WEST OF THE GENESEE RIVER VALLEY. AN
ISOLATED -SHRA OR SPRINKLE WILL BE POSSIBLE IN THIS REGION,
ALTHOUGH CHANCES ARE MINIMAL, SO HAVE LEFT THE MENTION OF SHOWER
ACTIVITY OUT OF THE TERMINAL FORECAST. VFR FLIGHT CONDITIONS WILL
LIKELY PREVAIL AT ALL TAF SITES THE REMAINDER OF TODAY.
TONIGHT...ANY LEFT OVER LOW/MID LEVEL CLOUDINESS SHOULD QUICKLY
DISSIPATE WITH THE LOSS OF DAYTIME HEATING AND VFR FLIGHT
CONDITIONS WILL CONTINUE AT ALL TAF LOCATIONS. THE ONLY EXCEPTION WILL BE
KJHW LATE, WHERE THE LOSS OF LOW/MID LEVEL CLOUDS AND HIGHER DEWPOINTS
MAY ALLOW FOG AFTER 07Z TO DEVELOP FOR IFR FLIGHT RULES. HOWEVER...THIS
WILL ALL DEPEND ON HOW MUCH CLOUDINESS IS PRESENT OVERNIGHT.
OUTLOOK...
MONDAY AND MONDAY NIGHT...MVFR WITH SHRA/TSRA LIKELY.
TUESDAY THRU FRIDAY...VFR.
&&
.MARINE...
SOUTHERLY WINDS INCREASING TO 10 TO 15 KNOTS OVER THE LAKES ARE
PRODUCING CHOPPY CONDITIONS. WITH WAVES UP TO THREE FEET TONIGHT
ACROSS EASTERN LAKE ONTARIO. OTHERWISE GOOD BOATING CONDITIONS
EXPECTED ON THE LAKES TODAY.
A COLD FRONT WILL CROSS THE LAKES MONDAY AFTERNOON AND EVENING
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. WESTERLY WINDS IN
THE WAKE OF THE FRONT WILL LIKELY RESULT IN SMALL CRAFT CONDITIONS
MONDAY AFTERNOON AND MONDAY NIGHT BEFORE HIGH PRESSURE BUILDS BACK
INTO THE REGION TUESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...AR/SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...AR
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1128 AM EDT SUN AUG 26 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING ONE LAST VERY WARM DAY TODAY...WITH
INCREASING CLOUDS AND A SLIGHT CHANCE OF SHOWERS IN THE AFTERNOON.
THE CHANCE FOR SHOWERS WILL INCREASE FURTHER ON MONDAY AND MONDAY
NIGHT AS A COLD FRONT CROSSES THE REGION. A RETURN TO SEASONABLY
NORMAL TEMPERATURES AND DRY WEATHER IS EXPECTED FOR THE MIDDLE
PORTION OF THE COMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MINOR CHANGES TO THE GRIDS...OTHERWISE FORECAST REMAINS ON TRACK.
PREVIOUS DISCUSSION FOLLOWS BELOW.
SURFACE HIGH PRESSURE IS CENTERED JUST OFF THE NEW ENGLAND COAST
WITH RIDGING EXTENDING BACK ACROSS NY INTO THE EASTERN OHIO VALLEY
THIS MORNING. ALOFT A CUT OFF LOW IS CYCLONICALLY SPINNING OVER THE
VIRGINIAS WITH SOME CONVECTION ACROSS THE DELMARVA. SATELLITE SHOWS
SOME SLOW SHIFT OF MID LAYER CLOUDS NORTHWARD INTO CENTRAL NY AND
THE INTERIOR SOUTHERN TIER.
LOOK FOR INCREASING CLOUDS THROUGH TODAY AS THE CUTOFF LOW CONTINUES TO
DRIFT NORTH. THE INCREASE IN CLOUD COVER AND SLIGHTLY COOLER
TEMPERATURES ALOFT ADVECTING INTO THE REGION ASSOCIATED WITH THE LOW
SHOULD YIELD COOLER TEMPERATURES...PARTICULARLY ACROSS THE SOUTHERN
TIER WHERE HIGHS SHOULD TOP OUT IN THE MID TO UPPER 70S. AREAS
FARTHER NORTH IN THE NIAGARA FRONTIER WILL LIKELY SEE ENOUGH
SUNSHINE TO CLIMB INTO THE LOW TO MID 80S AND THE WARMEST READINGS
WILL BE FOUND ACROSS THE NORTH COUNTRY WHERE SKIES SHOULD REMAIN
MOSTLY SUNNY THROUGHOUT THE DAY.
INCREASING LOW LEVEL MOISTURE WITH DEWPOINTS CREEPING BACK INTO THE
LOWER 60S AND NOMINAL COOLING ALOFT MAY BE JUST ENOUGH TO TRIGGER A
FEW SHOWERS...MAINLY ACROSS AREAS WEST OF THE GENESEE
VALLEY...HOWEVER GIVEN THE AMOUNT OF LINGERING DRY AIR...WIDESPREAD
CONVECTION IS NOT EXPECTED. THE 07Z RUN OF THE HRRR SHOWS SOME
SHOWERS POSSIBLE AROUND 20Z.
TONIGHT...ANY DIURNAL SHOWERS ACROSS WNY SHOULD END WITH HIGH
PRESSURE REMAINING OVER THE AREA. A COLD FRONT WILL CONTINUE TO
PRESS EAST TOWARD THE FORECAST AREA FROM MICHIGAN. CLOUD COVER WILL
INCREASING TOWARD OVERCAST WITH TEMPERATURES OVERNIGHT FALLING ONLY
INTO THE 60S...ON THE WARM SIDE WITH HIGHER HUMIDITY AROUND. FOG
WILL AGAIN BE LIMITED DUE TO WINDS NOT LOWERING TO CALM OVERNIGHT
AHEAD OF A COLD FRONT JUST TO THE WEST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
FOCUS IN THE SHORT TERM PERIOD WILL BE ON A COLD FRONTAL PASSAGE ON
MONDAY AND ASSOCIATED RAIN CHANCES. THERE REMAINS SOME TIMING
DIFFERENCES WITH THE GFS A GOOD 6 HOURS FASTER THAN THE NAM. THE
SLOWER NAM SOLUTION HAS SOME SUPPORT FROM THE CANADIAN GEM AND SREF
ENSEMBLE MEAN. WITH A WEAK DECAYING CLOSED LOW OVER THE MID ATLANTIC
LIKELY PROVING TO BE A ROADBLOCK TO UPSTREAM SYSTEMS...HAVE FAVORED
THE SLOWER NAM TIMING. WITH THIS IN MIND THE BULK OF THE AREA WILL
BE RAIN FREE MONDAY MORNING WITH INCREASING CLOUDS.
LATER IN THE DAY MODEST MID LEVEL HEIGHT FALLS AND PVA WILL APPROACH
THE REGION...WITH THE ASSOCIATED COLD FRONT ENTERING WESTERN NY BY
LATE AFTERNOON OR EVENING...THEN SWEEPING ACROSS THE REST OF THE
AREA MONDAY NIGHT. A 70+ KNOT UPPER LEVEL JET WILL ALSO PROVIDE SOME
UPPER LEVEL DIVERGENCE AS THE RIGHT ENTRANCE REGION BECOMES SITUATED
OVER THE LOWER LAKES MONDAY AFTERNOON. SEVERAL DAYS OF SOUTHERLY
FLOW AHEAD OF THIS SYSTEM WILL PROVIDE A DECENT MOISTURE RETURN...
WITH PWAT OF AROUND 1.5 INCHES AND SURFACE DEWPOINTS IN THE MID 60S
ON AVERAGE. WITH THIS MOISTURE AND FORCING COMING INTO PLAY...HAVE
INCREASED POPS TO LIKELY FOR THE FRONTAL PASSAGE. THE TIMING OF THE
MOST WIDESPREAD PRECIP WILL BE LATE AFTERNOON AND EARLY EVENING IN
WESTERN NY...AND MAINLY MONDAY EVENING AND NIGHT FROM THE GENESEE
VALLEY EAST INTO CENTRAL AND NORTHERN NY.
INSTABILITY WILL ONLY BE MARGINAL GIVEN THE VERY WARM TEMPS
ALOFT...WITH SBCAPE OF ONLY 500-1000J/KG. A TALL/SKINNY CAPE PROFILE
AND ADEQUATE MOISTURE SUGGEST POTENTIAL FOR LOCAL HEAVY DOWNPOURS
WITH ANY STORMS THAT FORM. THE WEAK INSTABILITY AND RELATIVELY WEAK
WIND FIELDS WILL KEEP STORMS POORLY ORGANIZED WITH LITTLE POTENTIAL
FOR ANY WIND OR HAIL. MONDAY WILL STILL BE QUITE WARM WITH 850MB
TEMPS OF AROUND +15C. WITH THE EXPECTATION THAT RAIN WILL HOLD OFF
UNTIL THE AFTERNOON...HAVE GONE ABOVE ALL MODEL GUIDANCE WITH HIGHS
IN THE MID 80S IN MANY LOCATIONS...ALONG WITH INCREASED HUMIDITY.
THE COLD FRONT AND ASSOCIATED RAIN WILL BE EAST OF THE CWA BY
DAYBREAK TUESDAY. A SECONDARY COLD FRONT AND ASSOCIATED MID LEVEL
SHORTWAVE WILL DROP INTO THE NORTH COUNTRY DURING THE DAY TUESDAY
AND MAY TOUCH OFF A FEW MORE WIDELY SCATTERED LIGHT SHOWERS. SOME
LIMITED MOISTURE ALONG AND AHEAD OF THIS SECONDARY TROUGH WILL ALSO
PRODUCE SOME DIURNAL CUMULUS...WITH A MIX OF SUN AND CLOUDS IN MANY
LOCATIONS. A SOMEWHAT COOLER AIRMASS WILL BUILD INTO THE AREA WITH
TEMPERATURES DROPPING BACK CLOSER TO AVERAGE. EXPECT HIGHS IN THE
MID TO UPPER 70S IN MOST LOCATIONS.
TUESDAY EVENING THE SECONDARY COLD FRONT WILL DROP SOUTH ACROSS THE
AREA WITH A PERIOD OF CLOUD COVER...FOLLOWED BY CLEARING SKIES
OVERNIGHT AND ADDITIONAL COLD AIR ADVECTION. THIS WILL ALLOW TEMPS
TO DROP INTO THE MID 50S ON THE LAKE PLAINS AND AROUND 50 IN THE
COOLER SOUTHERN TIER VALLEYS AND TUG HILL REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ON WEDNESDAY A LONGWAVE TROUGH WILL BECOME ESTABLISHED ACROSS
SOUTHEAST CANADA WITH A NORTHWEST FLOW OF COOLER AIR DIRECTED INTO
THE GREAT LAKES. SURFACE HIGH PRESSURE WILL BUILD INTO THE OHIO
VALLEY AND GREAT LAKES WITH A RETURN TO SUNSHINE. 850MB TEMPS OF
ONLY AROUND +8C WILL SUPPORT HIGHS IN THE MID 70S ACROSS LOWER
ELEVATIONS AND AROUND 70 ACROSS HIGHER TERRAIN. HIGH PRESSURE
OVERHEAD WEDNESDAY NIGHT WILL PROVIDE CLEAR SKIES AND A SEASONABLY
COOL NIGHT WITH MID 50S ON THE LAKE PLAINS AND A FEW UPPER 40S IN
THE COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE ONTARIO.
BY THURSDAY AND FRIDAY HIGH PRESSURE WILL BUILD QUICKLY TO THE EAST
COAST AND ALLOW SOUTHWEST RETURN FLOW TO INCREASE. 850MB TEMPS RISE
TO AROUND +14C THURSDAY AFTERNOON ON THE LATEST ECMWF...A LITTLE
WARMER EVEN ON THE GFS. IF THE TIMING HOLDS THIS WILL SUPPORT HIGHS
IN THE LOW TO MID 80S. BY FRIDAY A CENTRAL PLAINS ELEVATED MIXED
LAYER /EML/ PLUME BECOMES CAPTURED BY THE NEXT SYSTEM AND IS
ADVECTED EAST ALL THE WAY INTO THE LOWER LAKES WITH 850MB TEMPS
SOARING TO AROUND +20C. IF THIS VERIFIES...TEMPERATURES WILL MAKE IT
INTO THE 90S ONCE AGAIN WITH HEAT RETURNING. BOTH DAYS WILL BE DRY
AS AN UPPER LEVEL RIDGE SHIFTS EAST ACROSS THE PLAINS AND INTO THE
OHIO VALLEY AND GREAT LAKES.
BY SATURDAY FORECAST UNCERTAINTY INCREASES WITH RESPECT TO THE
TIMING AND PLACEMENT OF THE REMNANTS OF ISAAC. THE LATEST GFS
SPREADS SOME RAIN TOWARDS THE NY/PA BORDER...WHILE THE ECMWF KEEPS
THE SYSTEM CUTOFF AND WELL SOUTH OF THE AREA. PREVIOUS FORECAST HAD
SOME LOW CHANCE POPS AND WILL KEEP THOSE FOR NOW. THE FORECAST FOR
NEXT WEEKEND WILL BE UNCERTAIN FOR SEVERAL DAYS TO COME UNTIL MODEL
GUIDANCE COMES INTO BETTER AGREEMENT WITH THE TRACK OF ISAAC...AND
ITS EVENTUAL INTERACTION WITH THE MID LATITUDE WESTERLIES.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
VISIBLE SATELLITE SHOWS RAPID DEVELOPMENT OF CLOUD COVER ACROSS
WESTERN NY LATE THIS MORNING. THE RESULT OF MOISTURE STREAMING
NORTHWARD FROM THE UPPER LOW OVER VA/MD. RADAR IS ALSO PICKING UP
A FEW LIGHT SHOWERS OR SPRINKLES OVER THE NIAGARA FRONTIER AND
WESTERN SOUTHERN TIER. EXPECT MAINLY VFR CLOUD COVER OVER MOST TAF
LOCATIONS WITH A CHANCE OF -SHRA...GENERALLY FROM THE GENESEE
VALLEY WEST. 12Z HRRR MODEL IS HIGHLIGHTING THIS NICELY. THE LIGHT
SOUTHERLY BREEZE SHOULD PREVENT MOST FOG FORMATION TONIGHT EXCEPT
IN SHELTERED VALLEYS.
OUTLOOK...
MONDAY AND MONDAY NIGHT...MAINLY VFR WITH A CHC OF SHRA/TSRA.
TUESDAY...VFR. CHC SHRA MAINLY EAST.
WEDNESDAY AND THURSDAY...VFR.
&&
.MARINE...
SOUTHERLY WINDS INCREASING TO 10 TO 15 KNOTS OVER THE LAKES ARE
PRODUCING CHOPPY CONDITIONS. WITH WAVES UP TO THREE FEET TONIGHT
ACROSS EASTERN LAKE ONTARIO. OTHERWISE GOOD BOATING CONDITIONS
EXPECTED ON THE LAKES TODAY.
A COLD FRONT WILL CROSS THE LAKES MONDAY AFTERNOON AND EVENING
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. WESTERLY WINDS IN
THE WAKE OF THE FRONT WILL LIKELY RESULT IN SMALL CRAFT CONDITIONS
MONDAY AFTERNOON AND MONDAY NIGHT BEFORE HIGH PRESSURE BUILDS BACK
INTO THE REGION TUESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...AR/SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...AR/SMITH
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1030 AM EDT SUN AUG 26 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING ONE LAST VERY WARM DAY TODAY...WITH
INCREASING CLOUDS AND A SLIGHT CHANCE OF SHOWERS IN THE AFTERNOON.
THE CHANCE FOR SHOWERS WILL INCREASE FURTHER ON MONDAY AND MONDAY
NIGHT AS A COLD FRONT CROSSES THE REGION. A RETURN TO SEASONABLY
NORMAL TEMPERATURES AND DRY WEATHER IS EXPECTED FOR THE MIDDLE
PORTION OF THE COMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MINOR CHANGES TO THE GRIDS...OTHERWISE FORECAST REMAINS ON TRACK.
PREVIOUS DISCUSSION FOLLOWS BELOW.
SURFACE HIGH PRESSURE IS CENTERED JUST OFF THE NEW ENGLAND COAST
WITH RIDGING EXTENDING BACK ACROSS NY INTO THE EASTERN OHIO VALLEY
THIS MORNING. ALOFT A CUT OFF LOW IS CYCLONICALLY SPINNING OVER THE
VIRGINIAS WITH SOME CONVECTION ACROSS THE DELMARVA. SATELLITE SHOWS
SOME SLOW SHIFT OF MID LAYER CLOUDS NORTHWARD INTO CENTRAL NY AND
THE INTERIOR SOUTHERN TIER.
LOOK FOR INCREASING CLOUDS THROUGH TODAY AS THE CUTOFF LOW CONTINUES TO
DRIFT NORTH. THE INCREASE IN CLOUD COVER AND SLIGHTLY COOLER
TEMPERATURES ALOFT ADVECTING INTO THE REGION ASSOCIATED WITH THE LOW
SHOULD YIELD COOLER TEMPERATURES...PARTICULARLY ACROSS THE SOUTHERN
TIER WHERE HIGHS SHOULD TOP OUT IN THE MID TO UPPER 70S. AREAS
FARTHER NORTH IN THE NIAGARA FRONTIER WILL LIKELY SEE ENOUGH
SUNSHINE TO CLIMB INTO THE LOW TO MID 80S AND THE WARMEST READINGS
WILL BE FOUND ACROSS THE NORTH COUNTRY WHERE SKIES SHOULD REMAIN
MOSTLY SUNNY THROUGHOUT THE DAY.
INCREASING LOW LEVEL MOISTURE WITH DEWPOINTS CREEPING BACK INTO THE
LOWER 60S AND NOMINAL COOLING ALOFT MAY BE JUST ENOUGH TO TRIGGER A
FEW SHOWERS...MAINLY ACROSS AREAS WEST OF THE GENESEE
VALLEY...HOWEVER GIVEN THE AMOUNT OF LINGERING DRY AIR...WIDESPREAD
CONVECTION IS NOT EXPECTED. THE 07Z RUN OF THE HRRR SHOWS SOME
SHOWERS POSSIBLE AROUND 20Z.
TONIGHT...ANY DIURNAL SHOWERS ACROSS WNY SHOULD END WITH HIGH
PRESSURE REMAINING OVER THE AREA. A COLD FRONT WILL CONTINUE TO
PRESS EAST TOWARD THE FORECAST AREA FROM MICHIGAN. CLOUD COVER WILL
INCREASING TOWARD OVERCAST WITH TEMPERATURES OVERNIGHT FALLING ONLY
INTO THE 60S...ON THE WARM SIDE WITH HIGHER HUMIDITY AROUND. FOG
WILL AGAIN BE LIMITED DUE TO WINDS NOT LOWERING TO CALM OVERNIGHT
AHEAD OF A COLD FRONT JUST TO THE WEST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
FOCUS IN THE SHORT TERM PERIOD WILL BE ON A COLD FRONTAL PASSAGE ON
MONDAY AND ASSOCIATED RAIN CHANCES. THERE REMAINS SOME TIMING
DIFFERENCES WITH THE GFS A GOOD 6 HOURS FASTER THAN THE NAM. THE
SLOWER NAM SOLUTION HAS SOME SUPPORT FROM THE CANADIAN GEM AND SREF
ENSEMBLE MEAN. WITH A WEAK DECAYING CLOSED LOW OVER THE MID ATLANTIC
LIKELY PROVING TO BE A ROADBLOCK TO UPSTREAM SYSTEMS...HAVE FAVORED
THE SLOWER NAM TIMING. WITH THIS IN MIND THE BULK OF THE AREA WILL
BE RAIN FREE MONDAY MORNING WITH INCREASING CLOUDS.
LATER IN THE DAY MODEST MID LEVEL HEIGHT FALLS AND PVA WILL APPROACH
THE REGION...WITH THE ASSOCIATED COLD FRONT ENTERING WESTERN NY BY
LATE AFTERNOON OR EVENING...THEN SWEEPING ACROSS THE REST OF THE
AREA MONDAY NIGHT. A 70+ KNOT UPPER LEVEL JET WILL ALSO PROVIDE SOME
UPPER LEVEL DIVERGENCE AS THE RIGHT ENTRANCE REGION BECOMES SITUATED
OVER THE LOWER LAKES MONDAY AFTERNOON. SEVERAL DAYS OF SOUTHERLY
FLOW AHEAD OF THIS SYSTEM WILL PROVIDE A DECENT MOISTURE RETURN...
WITH PWAT OF AROUND 1.5 INCHES AND SURFACE DEWPOINTS IN THE MID 60S
ON AVERAGE. WITH THIS MOISTURE AND FORCING COMING INTO PLAY...HAVE
INCREASED POPS TO LIKELY FOR THE FRONTAL PASSAGE. THE TIMING OF THE
MOST WIDESPREAD PRECIP WILL BE LATE AFTERNOON AND EARLY EVENING IN
WESTERN NY...AND MAINLY MONDAY EVENING AND NIGHT FROM THE GENESEE
VALLEY EAST INTO CENTRAL AND NORTHERN NY.
INSTABILITY WILL ONLY BE MARGINAL GIVEN THE VERY WARM TEMPS
ALOFT...WITH SBCAPE OF ONLY 500-1000J/KG. A TALL/SKINNY CAPE PROFILE
AND ADEQUATE MOISTURE SUGGEST POTENTIAL FOR LOCAL HEAVY DOWNPOURS
WITH ANY STORMS THAT FORM. THE WEAK INSTABILITY AND RELATIVELY WEAK
WIND FIELDS WILL KEEP STORMS POORLY ORGANIZED WITH LITTLE POTENTIAL
FOR ANY WIND OR HAIL. MONDAY WILL STILL BE QUITE WARM WITH 850MB
TEMPS OF AROUND +15C. WITH THE EXPECTATION THAT RAIN WILL HOLD OFF
UNTIL THE AFTERNOON...HAVE GONE ABOVE ALL MODEL GUIDANCE WITH HIGHS
IN THE MID 80S IN MANY LOCATIONS...ALONG WITH INCREASED HUMIDITY.
THE COLD FRONT AND ASSOCIATED RAIN WILL BE EAST OF THE CWA BY
DAYBREAK TUESDAY. A SECONDARY COLD FRONT AND ASSOCIATED MID LEVEL
SHORTWAVE WILL DROP INTO THE NORTH COUNTRY DURING THE DAY TUESDAY
AND MAY TOUCH OFF A FEW MORE WIDELY SCATTERED LIGHT SHOWERS. SOME
LIMITED MOISTURE ALONG AND AHEAD OF THIS SECONDARY TROUGH WILL ALSO
PRODUCE SOME DIURNAL CUMULUS...WITH A MIX OF SUN AND CLOUDS IN MANY
LOCATIONS. A SOMEWHAT COOLER AIRMASS WILL BUILD INTO THE AREA WITH
TEMPERATURES DROPPING BACK CLOSER TO AVERAGE. EXPECT HIGHS IN THE
MID TO UPPER 70S IN MOST LOCATIONS.
TUESDAY EVENING THE SECONDARY COLD FRONT WILL DROP SOUTH ACROSS THE
AREA WITH A PERIOD OF CLOUD COVER...FOLLOWED BY CLEARING SKIES
OVERNIGHT AND ADDITIONAL COLD AIR ADVECTION. THIS WILL ALLOW TEMPS
TO DROP INTO THE MID 50S ON THE LAKE PLAINS AND AROUND 50 IN THE
COOLER SOUTHERN TIER VALLEYS AND TUG HILL REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ON WEDNESDAY A LONGWAVE TROUGH WILL BECOME ESTABLISHED ACROSS
SOUTHEAST CANADA WITH A NORTHWEST FLOW OF COOLER AIR DIRECTED INTO
THE GREAT LAKES. SURFACE HIGH PRESSURE WILL BUILD INTO THE OHIO
VALLEY AND GREAT LAKES WITH A RETURN TO SUNSHINE. 850MB TEMPS OF
ONLY AROUND +8C WILL SUPPORT HIGHS IN THE MID 70S ACROSS LOWER
ELEVATIONS AND AROUND 70 ACROSS HIGHER TERRAIN. HIGH PRESSURE
OVERHEAD WEDNESDAY NIGHT WILL PROVIDE CLEAR SKIES AND A SEASONABLY
COOL NIGHT WITH MID 50S ON THE LAKE PLAINS AND A FEW UPPER 40S IN
THE COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE ONTARIO.
BY THURSDAY AND FRIDAY HIGH PRESSURE WILL BUILD QUICKLY TO THE EAST
COAST AND ALLOW SOUTHWEST RETURN FLOW TO INCREASE. 850MB TEMPS RISE
TO AROUND +14C THURSDAY AFTERNOON ON THE LATEST ECMWF...A LITTLE
WARMER EVEN ON THE GFS. IF THE TIMING HOLDS THIS WILL SUPPORT HIGHS
IN THE LOW TO MID 80S. BY FRIDAY A CENTRAL PLAINS ELEVATED MIXED
LAYER /EML/ PLUME BECOMES CAPTURED BY THE NEXT SYSTEM AND IS
ADVECTED EAST ALL THE WAY INTO THE LOWER LAKES WITH 850MB TEMPS
SOARING TO AROUND +20C. IF THIS VERIFIES...TEMPERATURES WILL MAKE IT
INTO THE 90S ONCE AGAIN WITH HEAT RETURNING. BOTH DAYS WILL BE DRY
AS AN UPPER LEVEL RIDGE SHIFTS EAST ACROSS THE PLAINS AND INTO THE
OHIO VALLEY AND GREAT LAKES.
BY SATURDAY FORECAST UNCERTAINTY INCREASES WITH RESPECT TO THE
TIMING AND PLACEMENT OF THE REMNANTS OF ISAAC. THE LATEST GFS
SPREADS SOME RAIN TOWARDS THE NY/PA BORDER...WHILE THE ECMWF KEEPS
THE SYSTEM CUTOFF AND WELL SOUTH OF THE AREA. PREVIOUS FORECAST HAD
SOME LOW CHANCE POPS AND WILL KEEP THOSE FOR NOW. THE FORECAST FOR
NEXT WEEKEND WILL BE UNCERTAIN FOR SEVERAL DAYS TO COME UNTIL MODEL
GUIDANCE COMES INTO BETTER AGREEMENT WITH THE TRACK OF ISAAC...AND
ITS EVENTUAL INTERACTION WITH THE MID LATITUDE WESTERLIES.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS THE AREA
REMAINS UNDER THE INFLUENCE OF HIGH PRESSURE. INCREASING
MOISTURE FROM THE SOUTHEAST WILL USHER IN INCREASED VFR CLOUD COVER
LATER TODAY WITH A CHANCE OF SHRA AFTER 18Z GENERALLY FROM THE
GENESEE VALLEY WEST. 07Z HRRR MODEL IS HIGHLIGHTING THIS. THE LIGHT
SOUTHERLY BREEZE SHOULD PREVENT MOST FOG FORMATION TONIGHT EXCEPT IN
SHELTERED VALLEYS.
OUTLOOK...
MONDAY AND MONDAY NIGHT...MAINLY VFR WITH A CHC OF SHRA/TSRA.
TUESDAY...VFR. CHC SHRA MAINLY EAST.
WEDNESDAY AND THURSDAY...VFR.
&&
.MARINE...
SOUTHERLY WINDS INCREASING TO 10 TO 15 KNOTS OVER THE LAKES ARE
PRODUCING CHOPPY CONDITIONS. WITH WAVES UP TO THREE FEET TONIGHT
ACROSS EASTERN LAKE ONTARIO. OTHERWISE GOOD BOATING CONDITIONS
EXPECTED ON THE LAKES TODAY.
A COLD FRONT WILL CROSS THE LAKES MONDAY AFTERNOON AND EVENING
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. WESTERLY WINDS IN
THE WAKE OF THE FRONT WILL LIKELY RESULT IN SMALL CRAFT CONDITIONS
MONDAY AFTERNOON AND MONDAY NIGHT BEFORE HIGH PRESSURE BUILDS BACK
INTO THE REGION TUESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...AR/SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
757 AM EDT SUN AUG 26 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING ONE LAST VERY WARM DAY TODAY...WITH
INCREASING CLOUDS AND A SLIGHT CHANCE OF SHOWERS IN THE AFTERNOON.
THE CHANCE FOR SHOWERS WILL INCREASE FURTHER ON MONDAY AND MONDAY
NIGHT AS A COLD FRONT CROSSES THE REGION. A RETURN TO SEASONABLY
NORMAL TEMPERATURES AND DRY WEATHER IS EXPECTED FOR THE MIDDLE
PORTION OF THE COMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE HIGH PRESSURE IS CENTERED JUST OFF THE NEW ENGLAND COAST
WITH RIDGING EXTENDING BACK ACROSS NY INTO THE EASTERN OHIO VALLEY
THIS MORNING. ALOFT A CUT OFF LOW IS CYCLONICALLY SPINNING OVER THE
VIRGINIAS WITH SOME CONVECTION ACROSS THE DELMARVA. SATELLITE SHOWS
SOME SLOW SHIFT OF MID LAYER CLOUDS NORTHWARD INTO CENTRAL NY AND
THE INTERIOR SOUTHERN TIER. OTHERWISE CLEAR SKIES OUTSIDE OF VERY
LIMITED FOG BEING REPORTED AT BFD AND ELZ.
LOOK FOR INCREASING CLOUDS THROUGH TODAY AS THE CUTOFF LOW CONTINUES TO
DRIFT NORTH. THE INCREASE IN CLOUD COVER AND SLIGHTLY COOLER
TEMPERATURES ALOFT ADVECTING INTO THE REGION ASSOCIATED WITH THE LOW
SHOULD YIELD COOLER TEMPERATURES...PARTICULARLY ACROSS THE SOUTHERN
TIER WHERE HIGHS SHOULD TOP OUT IN THE MID TO UPPER 70S. AREAS
FARTHER NORTH IN THE NIAGARA FRONTIER WILL LIKELY SEE ENOUGH
SUNSHINE TO CLIMB INTO THE LOW TO MID 80S AND THE WARMEST READINGS
WILL BE FOUND ACROSS THE NORTH COUNTRY WHERE SKIES SHOULD REMAIN
MOSTLY SUNNY THROUGHOUT THE DAY.
INCREASING LOW LEVEL MOISTURE WITH DEWPOINTS CREEPING BACK INTO THE
LOWER 60S AND NOMINAL COOLING ALOFT MAY BE JUST ENOUGH TO TRIGGER A
FEW SHOWERS...MAINLY ACROSS AREAS WEST OF THE GENESEE
VALLEY...HOWEVER GIVEN THE AMOUNT OF LINGERING DRY AIR...WIDESPREAD
CONVECTION IS NOT EXPECTED. THE 07Z RUN OF THE HRRR SHOWS SOME
SHOWERS POSSIBLE AROUND 20Z.
TONIGHT...ANY DIURNAL SHOWERS ACROSS WNY SHOULD END WITH HIGH
PRESSURE REMAINING OVER THE AREA. A COLD FRONT WILL CONTINUE TO
PRESS EAST TOWARD THE FORECAST AREA FROM MICHIGAN. CLOUD COVER WILL
INCREASING TOWARD OVERCAST WITH TEMPERATURES OVERNIGHT FALLING ONLY
INTO THE 60S...ON THE WARM SIDE WITH HIGHER HUMIDITY AROUND. FOG
WILL AGAIN BE LIMITED DUE TO WINDS NOT LOWERING TO CALM OVERNIGHT
AHEAD OF A COLD FRONT JUST TO THE WEST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
FOCUS IN THE SHORT TERM PERIOD WILL BE ON A COLD FRONTAL PASSAGE ON
MONDAY AND ASSOCIATED RAIN CHANCES. THERE REMAINS SOME TIMING
DIFFERENCES WITH THE GFS A GOOD 6 HOURS FASTER THAN THE NAM. THE
SLOWER NAM SOLUTION HAS SOME SUPPORT FROM THE CANADIAN GEM AND SREF
ENSEMBLE MEAN. WITH A WEAK DECAYING CLOSED LOW OVER THE MID ATLANTIC
LIKELY PROVING TO BE A ROADBLOCK TO UPSTREAM SYSTEMS...HAVE FAVORED
THE SLOWER NAM TIMING. WITH THIS IN MIND THE BULK OF THE AREA WILL
BE RAIN FREE MONDAY MORNING WITH INCREASING CLOUDS.
LATER IN THE DAY MODEST MID LEVEL HEIGHT FALLS AND PVA WILL APPROACH
THE REGION...WITH THE ASSOCIATED COLD FRONT ENTERING WESTERN NY BY
LATE AFTERNOON OR EVENING...THEN SWEEPING ACROSS THE REST OF THE
AREA MONDAY NIGHT. A 70+ KNOT UPPER LEVEL JET WILL ALSO PROVIDE SOME
UPPER LEVEL DIVERGENCE AS THE RIGHT ENTRANCE REGION BECOMES SITUATED
OVER THE LOWER LAKES MONDAY AFTERNOON. SEVERAL DAYS OF SOUTHERLY
FLOW AHEAD OF THIS SYSTEM WILL PROVIDE A DECENT MOISTURE RETURN...
WITH PWAT OF AROUND 1.5 INCHES AND SURFACE DEWPOINTS IN THE MID 60S
ON AVERAGE. WITH THIS MOISTURE AND FORCING COMING INTO PLAY...HAVE
INCREASED POPS TO LIKELY FOR THE FRONTAL PASSAGE. THE TIMING OF THE
MOST WIDESPREAD PRECIP WILL BE LATE AFTERNOON AND EARLY EVENING IN
WESTERN NY...AND MAINLY MONDAY EVENING AND NIGHT FROM THE GENESEE
VALLEY EAST INTO CENTRAL AND NORTHERN NY.
INSTABILITY WILL ONLY BE MARGINAL GIVEN THE VERY WARM TEMPS
ALOFT...WITH SBCAPE OF ONLY 500-1000J/KG. A TALL/SKINNY CAPE PROFILE
AND ADEQUATE MOISTURE SUGGEST POTENTIAL FOR LOCAL HEAVY DOWNPOURS
WITH ANY STORMS THAT FORM. THE WEAK INSTABILITY AND RELATIVELY WEAK
WIND FIELDS WILL KEEP STORMS POORLY ORGANIZED WITH LITTLE POTENTIAL
FOR ANY WIND OR HAIL. MONDAY WILL STILL BE QUITE WARM WITH 850MB
TEMPS OF AROUND +15C. WITH THE EXPECTATION THAT RAIN WILL HOLD OFF
UNTIL THE AFTERNOON...HAVE GONE ABOVE ALL MODEL GUIDANCE WITH HIGHS
IN THE MID 80S IN MANY LOCATIONS...ALONG WITH INCREASED HUMIDITY.
THE COLD FRONT AND ASSOCIATED RAIN WILL BE EAST OF THE CWA BY
DAYBREAK TUESDAY. A SECONDARY COLD FRONT AND ASSOCIATED MID LEVEL
SHORTWAVE WILL DROP INTO THE NORTH COUNTRY DURING THE DAY TUESDAY
AND MAY TOUCH OFF A FEW MORE WIDELY SCATTERED LIGHT SHOWERS. SOME
LIMITED MOISTURE ALONG AND AHEAD OF THIS SECONDARY TROUGH WILL ALSO
PRODUCE SOME DIURNAL CUMULUS...WITH A MIX OF SUN AND CLOUDS IN MANY
LOCATIONS. A SOMEWHAT COOLER AIRMASS WILL BUILD INTO THE AREA WITH
TEMPERATURES DROPPING BACK CLOSER TO AVERAGE. EXPECT HIGHS IN THE
MID TO UPPER 70S IN MOST LOCATIONS.
TUESDAY EVENING THE SECONDARY COLD FRONT WILL DROP SOUTH ACROSS THE
AREA WITH A PERIOD OF CLOUD COVER...FOLLOWED BY CLEARING SKIES
OVERNIGHT AND ADDITIONAL COLD AIR ADVECTION. THIS WILL ALLOW TEMPS
TO DROP INTO THE MID 50S ON THE LAKE PLAINS AND AROUND 50 IN THE
COOLER SOUTHERN TIER VALLEYS AND TUG HILL REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ON WEDNESDAY A LONGWAVE TROUGH WILL BECOME ESTABLISHED ACROSS
SOUTHEAST CANADA WITH A NORTHWEST FLOW OF COOLER AIR DIRECTED INTO
THE GREAT LAKES. SURFACE HIGH PRESSURE WILL BUILD INTO THE OHIO
VALLEY AND GREAT LAKES WITH A RETURN TO SUNSHINE. 850MB TEMPS OF
ONLY AROUND +8C WILL SUPPORT HIGHS IN THE MID 70S ACROSS LOWER
ELEVATIONS AND AROUND 70 ACROSS HIGHER TERRAIN. HIGH PRESSURE
OVERHEAD WEDNESDAY NIGHT WILL PROVIDE CLEAR SKIES AND A SEASONABLY
COOL NIGHT WITH MID 50S ON THE LAKE PLAINS AND A FEW UPPER 40S IN
THE COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE ONTARIO.
BY THURSDAY AND FRIDAY HIGH PRESSURE WILL BUILD QUICKLY TO THE EAST
COAST AND ALLOW SOUTHWEST RETURN FLOW TO INCREASE. 850MB TEMPS RISE
TO AROUND +14C THURSDAY AFTERNOON ON THE LATEST ECMWF...A LITTLE
WARMER EVEN ON THE GFS. IF THE TIMING HOLDS THIS WILL SUPPORT HIGHS
IN THE LOW TO MID 80S. BY FRIDAY A CENTRAL PLAINS ELEVATED MIXED
LAYER /EML/ PLUME BECOMES CAPTURED BY THE NEXT SYSTEM AND IS
ADVECTED EAST ALL THE WAY INTO THE LOWER LAKES WITH 850MB TEMPS
SOARING TO AROUND +20C. IF THIS VERIFIES...TEMPERATURES WILL MAKE IT
INTO THE 90S ONCE AGAIN WITH HEAT RETURNING. BOTH DAYS WILL BE DRY
AS AN UPPER LEVEL RIDGE SHIFTS EAST ACROSS THE PLAINS AND INTO THE
OHIO VALLEY AND GREAT LAKES.
BY SATURDAY FORECAST UNCERTAINTY INCREASES WITH RESPECT TO THE
TIMING AND PLACEMENT OF THE REMNANTS OF ISAAC. THE LATEST GFS
SPREADS SOME RAIN TOWARDS THE NY/PA BORDER...WHILE THE ECMWF KEEPS
THE SYSTEM CUTOFF AND WELL SOUTH OF THE AREA. PREVIOUS FORECAST HAD
SOME LOW CHANCE POPS AND WILL KEEP THOSE FOR NOW. THE FORECAST FOR
NEXT WEEKEND WILL BE UNCERTAIN FOR SEVERAL DAYS TO COME UNTIL MODEL
GUIDANCE COMES INTO BETTER AGREEMENT WITH THE TRACK OF ISAAC...AND
ITS EVENTUAL INTERACTION WITH THE MID LATITUDE WESTERLIES.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AS THE AREA
REMAINS UNDER THE INFLUENCE OF HIGH PRESSURE. INCREASING
MOISTURE FROM THE SOUTHEAST WILL USHER IN INCREASED VFR CLOUD COVER
LATER TODAY WITH A CHANCE OF SHRA AFTER 18Z GENERALLY FROM THE
GENESEE VALLEY WEST. 07Z HRRR MODEL IS HIGHLIGHTING THIS. THE LIGHT
SOUTHERLY BREEZE SHOULD PREVENT MOST FOG FORMATION TONIGHT EXCEPT IN
SHELTERED VALLEYS.
OUTLOOK...
MONDAY AND MONDAY NIGHT...MAINLY VFR WITH A CHC OF SHRA/TSRA.
TUESDAY...VFR. CHC SHRA MAINLY EAST.
WEDNESDAY AND THURSDAY...VFR.
&&
.MARINE...
SOUTHERLY WINDS INCREASING TO 10 TO 15 KNOTS OVER THE LAKES ARE
PRODUCING CHOPPY CONDITIONS. WITH WAVES UP TO THREE FEET TONIGHT
ACROSS EASTERN LAKE ONTARIO. OTHERWISE GOOD BOATING CONDITIONS
EXPECTED ON THE LAKES TODAY.
A COLD FRONT WILL CROSS THE LAKES MONDAY AFTERNOON AND EVENING
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. WESTERLY WINDS IN
THE WAKE OF THE FRONT WILL LIKELY RESULT IN SMALL CRAFT CONDITIONS
MONDAY AFTERNOON AND MONDAY NIGHT BEFORE HIGH PRESSURE BUILDS BACK
INTO THE REGION TUESDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...JJR/SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...HITCHCOCK/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
835 PM EDT MON AUG 27 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH NC FROM THE NORTHWEST LATE TUESDAY OR
TUESDAY NIGHT. THE SLOW MOVING COLD FRONT COULD POTENTIALLY STALL
ACROSS THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM MONDAY...
LATEST SURFACE ANALYSIS SHOWS TROPICAL STORM ISAAC IN THE
EAST-CENTRAL GULF OF MEXICO. A SOUTHEASTERLY LOW LEVEL FLOW OFF THE
ATLANTIC ASSOCIATED WITH ISAAC COMBINED WITH A NARROW RIDGE OF HIGH
PRESSURE EXTENDING SOUTHWESTWARD ACROSS THE WESTERN PIEDMONT OF VA
AND NC HAS RESULTED IN THE DEVELOPMENT OF AN INLAND PENETRATING
COASTAL FRONT. THE FRONT HAS BEEN ENHANCED BY SEA BREEZE BOUNDARIES
ACROSS SOUTHERN COASTAL AREAS AND WITH CONVECTIVE OUTFLOW ACROSS THE
CENTRAL COASTAL AREA. AN AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS IS ASSOCIATED WITH THE BOUNDARY...ELSEWHERE FAIR
WEATHER WITH SCT-BKN CUMULUS IS WIDESPREAD ACROSS THE REMAINDER OF
CENTRAL NORTH CAROLINA.
THE CONVECTION IS EXPECTED TO CONTINUE ADVANCING NORTHWEST THIS
AFTERNOON AND EARLY EVENING. AIDED BY A WEAKLY UNSTABLE AIR MASS
WITH MLCAPE VALUES RANGING FROM 500-1000 J/KG AND ONLY MODEST MID
LEVEL LAPSE RATES. THE CONVECTION IS EXPECTED TO DECREASE IN
COVERAGE AND INTENSITY AS IT MOVES FURTHER INLAND TOWARD THE SFC
RIDGE AND INTO A REGION OF DEW POINTS IN THE MID/UPPER 60S AND
RESULTANT MLCAPE VALUES OF LESS THAN 500 J/KG. THIS TREND IS
SUPPORTED BY RECENT HRRR RUNS WHICH HAS HANDLED THIS WELL. THE
PRECIPITATION MAY LINGER INTO THE EVENING HOURS...MAINLY ACROSS THE
SOUTHERN COASTAL PLAIN/SANDHILLS/SOUTHERN PIEDMONT BEFORE FAIR
WEATHER ARRIVES ACROSS CENTRAL LATE THIS EVENING AND OVERNIGHT.
ANOTHER ROUND OF STRATUS AND FOG IS EXPECTED TO DEVELOP LATE
TONIGHT. WITH A SUB-TROPICAL AIR MASS IN PLACE ACROSS THE
REGION...LOWS TONIGHT SHOULD FALL INTO THE 67-72 RANGE FROM WEST TO
EAST. -BLAES
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
AS OF 315 PM MONDAY...
A NORTHERN STREAM SHORT WAVE AND THE ASSOCIATED COLD FRONT WILL BE
MOVING ACROSS THE CENTRAL APPALACHIANS EARLY TUESDAY. THE
SOUTHEASTERLY LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY AHEAD OF THE
FRONT. AN AREA OF CONVECTION OFF THE FL COAST ASSOCIATED WITH A LOW
LEVEL PERTURBATION WILL ADVANCE NORTH AND NORTHEAST AND MOVE ACROSS
EASTERN AND SOUTHEASTERN SC/NC. RECENT GUIDANCE SUGGESTS THAT THIS
FEATURE WILL LIKELY NOT INTERACT WITH THE FRONT A GREAT DEAL. STILL
THE PERTURBATION IN A REGION OF HIGH PRECIPITABLE WATER THAT WILL BE
ENHANCED BY THE ENTRANCE REGION OF A JET ALOFT WILL PRODUCE AN AREA
OF SHOWERS AND THUNDERSTORMS THAT MOVES ACROSS THE
SOUTHERN/SOUTHEASTERN PORTION OF THE CWA LATE TUESDAY MORNING AND
CONTINUES INTO THE EVENING HOURS. HAVE OPTED TO HOLD OFF ON
INCLUDING LIKELY POPS GIVEN RECENT GUIDANCE FROM CONVECTION ALLOWING
MODELS. AT THIS POINT QPF VALUES ARE EXPECTED TO BE LIMITED AND
GENERALLY RANGE AROUND A HALF INCH WITH A FEW LOCATIONS RECEIVING UP
TO AN INCH. THE SEVERE THREAT AT THIS TIME APPEARS SOMEWHAT LIMITED
WITH MODEST DEEP LAYER SHEAR OF AROUND 20KTS AND A WEAKLY UNSTABLE
AIRMASS WITH MLCAPE VALUES OF 500-1000 J/KG. LOCALIZED HEAVY RAIN IS
THE LARGER THREAT AT THIS TIME.
THE COLD FRONT IS EXPECTED TO SLOWLY DROP SOUTHWARD REACHING THE
SOUTHERN COASTAL PLAIN BY DAYBREAK WEDNESDAY. WITH THE FRONT IN THE
VICINITY AND A DEEP SOUTHERLY FLOW...WIDESPREAD CLOUDINESS SHOULD
DEVELOP AND PERSIST THROUGH THE PERIOD. HIGH TEMPERATURES WILL RANGE
IN THE UPPER 80S ACROSS THE NORTHEAST TO MID 80S ELSEWHERE. LOWS ON
TUESDAY NIGHT WILL RANGE IN THE UPPER 60S TO LOWER 70S. -BLAES
A COLD FRONT WILL BE PUSHING SOUTH THROUGH THE CWA BY 12Z WEDNESDAY
MORNING. THE ASSOCIATED MID LEVEL SHEAR AXIS WILL ALSO PUSH SOUTH
INTO THE AREA...THOUGH MODELS ARE WEAKER WITH THIS FEATURE WITH A
WESTWARD SHIFT IN THE MODEL/NHC TRACK OF TS ISAAC AND LESS
INTERACTION WITH THE SHORTWAVE CROSSING NEW ENGLAND. MODELS SHOW
THE 85OMB TROUGH AXIS DRAPED ACROSS THE AREA JUST NORTH OF THE NC/SC
BORDER WEDNESDAY...WITH PW IN EXCESS OF 2 INCHES JUST TO THE
SOUTH. THE FRONTAL ZONE WILL BE SLOWING AT THAT POINT...SO THE
DELINEATION BETWEEN WIDESPREAD SHOWERS AND DRY CONDITIONS WILL BE
NARROW...ALTHOUGH THE RIGHT ENTRANCE REGION OF A WESTWARD BUILDING
UPPER JET WILL PROVIDE BROAD LIFT TO SUPPORT AT LEAST CHANCE POPS
AREAWIDE. THERE IS THE POTENTIAL HIGHS TO BE WARMER NORTH THAN
SOUTH DEPENDING ON PRECIP COVERAGE AND POTENTIAL BREAKS IN OVERCAST
SKIES...WITH MID 80S POSSIBLE NORTH AND LOWER 80S MORE LIKELY SOUTH.
INSTABILITY SHOULD BE LIMITED BY CLOUD COVER AND WEAK MID LEVEL WIND
FIELDS SHOULD LIMIT AN SEVERE THREAT WEDNESDAY AFTERNOON.
HOWEVER...SHOWERS AND STORMS WILL HAVE HEAVY RAIN WITH A STORM
MOTION SOMEWHAT PARALLEL TO THE FRONT...SO A FLOODING THREAT MAY
EXIST.
THE SURFACE FRONT AND LOW LEVEL TROUGH SHOULD SLIP FURTHER SOUTH
WEDNESDAY NIGHT...AND WITH IT THE FOCUS FOR BETTER PRECIP COVERAGE.
HOWEVER...WE WILL MAINTAIN A CHANCE POPS FOR THE SOUTHERN PIEDMONT
AND SANDHILLS INTO THE OVERNIGHT HOURS AND EARLY
THURSDAY....DECREASING FROM NORTH TO SOUTH ON THURSDAY. LOWS
RANGING FROM THE MID 60S NORTHEAST TO UPPER 60S SOUTHWEST. HIGHS
THURSDAY IN THE MID 80S. -SMITH
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 315 PM MONDAY...
WITH MODELS CONTINUING TO SHIFT SLIGHTLY WESTWARD WITH THE TRACK OF
TS ISAAC...THERE IS STILL QUITE A BIT OF UNCERTAINTY REGARDING THE
EVOLUTION AND TRACK OF ITS REMNANTS...AND HOW THAT WILL PLAY OUT
OVER THE EASTERN US DURING THE UPCOMING WEEKEND INTO EARLY NEXT
WEEK. IN GENERAL...THE REMNANTS OF ISAAC ARE FORECAST TO MOVE
NORTH THROUGH THE CENTRAL PLAINS...AROUND THE MID LEVEL RIDGE AS
THE RIDGE ITSELF BUILDS EAST THE OH VALLEY REGION. MODELS SHOW THE
MID LEVEL RIDGE SHIFTING OVER THE VIRGINIAS/CAROLINAS BY FRIDAY
AND SATURDAY...WITH THE BETTER MOISTURE PLUME SURGING NORTH
BETWEEN THE MS RIVER AND TN VALLEY REGIONS. THIS WOULD GREATLY
REDUCE THE POTENTIAL FOR SHOWERS AND STORMS OVER CENTRAL NC FRIDAY
AND SATURDAY...WITH MOST ACTIVITY FROM THE MOUNTAINS WESTWARD.
CLOUD COVER WILL ALSO BE GREATEST OVER THE WEST....AND HIGHS WILL
ACCORDING VARY FROM SOUTHWEST TO NORTHEAST. UNDER A STRENGTHENING
MID LEVEL RIDGE...MODELS INDICATE 850MB TEMPS APPROACHING 18-19C BY
SATURDAY AND SUNDAY...WHICH BY ITSELF WOULD SUGGEST HIGHS IN THE
MID 90S. THERE IS LIKELY TO BE QUITE A BIT OF CIRRUS EAST OF THE
REMNANTS OF ISAAC...SO HIGHS IN THE UPPER 80S AND LOWER 90S SEEM
MORE REASONABLE AT THIS POINT.
MODELS THEN DIVERGE A BIT BEYOND 00Z SUNDAY REGARDING THE REMNANT
MID LEVEL PV FROM ISAAC...WHICH THE 12Z GFS NOW SHOWING A DEEPER
AN STRONGER MID/UPPER LOW SINKING INTO THE TN VALLEY SUNDAY. THE
12Z ECMWF NOW SHOWS SIGNS OF THE CIRCULATION EVENTUALLY DRIFTING
SOUTHEAST TOWARD THE TN VALLEY AND SOUTHEAST US...WHICH IS
REMARKABLY DIFFERENT THAT ITS PREVIOUS RUN. WE WILL CONTINUE TO
SHOW AN INCREASE IN POPS INTO EARLY NEXT WEEK...ALTHOUGH
CONFIDENCE IS TOO LOW TO INCREASE THE CURRENT SLIGHT CHANCE TO LOW
CHANCE WORDING.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 835 PM MONDAY...
GENERALLY VFR CONDITIONS WILL PREVAIL THROUGH 06Z... THEN IFR/LIFR
CIGS WILL OVERSPREAD THE KFAY TO KRWI AREAS BETWEEN 06Z-09Z... THEN
POTENTIALLY THE KRDU TO KINT AREAS AFTER 09Z. MVFR FOG WILL BE
POSSIBLE BETWEEN 06Z-12Z FROM KFAY TO KRWI. CIGS WILL IMPROVE TO VFR
BY LATE MORNING TUESDAY WITH VFR VSBYS EXPECTED. SCATTERED SHOWERS
AND THUNDERSTORMS ARE FORECAST TUESDAY AFTERNOON AND NIGHT...
OTHERWISE VFR CONDITIONS EXPECTED THROUGH 06Z/WED... BECOMING
LIFR/IFR LATE.
A PERIOD OF ADVERSE AVIATION CONDITIONS MAY IMPACT THE AREA FROM
LATE TUESDAY THROUGH THURSDAY WITH SUB VFR CEILINGS AS WELL AS
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MORE WIDELY
SCATTERED SHOWERS WITH A REDUCED POTENTIAL FOR ADVERSE IMPACT IS
EXPECTED ON FRIDAY AND SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BLAES
SHORT TERM...BLAES/SMITH
LONG TERM...SMITH
AVIATION...BADGETT/BSD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
619 PM EDT SUN AUG 26 2012
.SYNOPSIS...
AN UPPER LOW OVER NORTHWEST VIRGINIA THIS EVENING WILL WEAKEN AS
IT LIFTS SLOWLY TOWARD THE DELMARVA TONIGHT. THIS CIRCULATION
WILL BE ABSORBED INTO A LARGER SCALE TROUGH MOVING EASTWARD FROM
THE GREAT LAKES INTO THE NORTHEAST STATES THROUGH MONDAY NIGHT.
THE GREAT LAKES TROUGH WILL SEND A COLD FRONT ACROSS THE REGION BY
EARLY TUESDAY. HIGH PRESSURE WILL SHIFT SOUTHEAST FROM THE UPPER
MIDWEST INTO PENNSYLVANIA FOR THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
THINGS ARE BEGINNING TO QUIET DOWN AFTER A RAPID INCREASE IN
CONVECTIVE ACTIVITY DURING THE MID-LATE AFTN. BULK OF RADAR
RETURNS ARE NOW MAINLY STRATI FORM RAINS SOUTH OF THE LEADING EDGE
GUST FNT SURGING NWD INTO THE N-CNTRL MTNS. 25-35KT GUSTS ARE
STILL POSSIBLE AHEAD OF THE N-NWWD PROPAGATING GUST FRONT...BUT
LIMITED INSTABILITY AND LWR DEWPOINTS SHOULD SPELL AN END TO THIS
ACTIVITY. MODIFIED POPS THRU 03Z TO REFLECT CURRENT PCPN AXIS FM
THV/MDT N-NWWD TO PHILIPSBURG/RENOVO/IPT VCNTY. FF WATCH REMAINS
IN EFFECT UNTL 10 PM...BUT HEAVIEST RNFL IS NOW WELL TO THE SOUTH
OVR THE CHESAPEAKE/DELMARVA REGIONS.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH MONDAY NIGHT/...
EXPECT LOW CLOUDS TO PERSIST TONIGHT ACRS THE CENTRAL MTNS AND
SERN PA. LATEST HRRR SHOWS MUCH OF THE PCPN DISSIPATING BY 03Z.
HOWEVER WILL STILL HANG ONTO HIGH CHC-LOW LKLY POPS THRU 06Z IN
THE EAST.
PESKY MID-UPPER LVL CIRCULATION IN THE MID-ATLC STATES WILL BE
LIFTING NEWD FM THE DELMARVA AT THE START OF THE PD. THIS FEATURE
WILL BE ABSORBED INTO LARGE SCALE TROUGH FCST TO SHIFT SEWD FROM
THE GREAT LAKES INTO THE NORTHEAST.
WEAK RIDGING BTWN THE DEPARTING/WEAKENING UPPER LEVEL CIRCULATION
AND APPROACHING LW TROUGH SHOULD BRING DRIER AND WARMER WX TO
CENTRAL PA BY THE AFTN...WITH ANY SHOWER ACTIVITY ENDING EARLY IN
THE DAY ACROSS THE EASTERN COUNTIES. HOWEVER MAIN QUESTION IS HOW
FAST THE LOW CLOUDS WILL ERODE. WITH THE LLVL FLOW GRADUALLY
VEERING MORE THE WSW...ANTICIPATE A SLOW IMPROVEMENT WITH PEAKS OF
SUN LKLY BY THE AFTN. FOCUS FOR CONVECTION WILL SHIFT TO ELONGATED
SFC COLD FRONT ASSOC WITH THE LG SCALE TROF DIGGING INTO THE NE
STATES. BEST CHC FOR LATE AFTN TSTM WILL BE OVER THE NW MTNS WITH
POPS INCREASING INTO THE CENTRAL ZONES MON NGT.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE COLD FRONT WILL PASS TO OUR SOUTH AND EAST LATE MONDAY NIGHT
OR EARLY TUESDAY...TAKING ANY LINGERING SHRA/TSRA WITH IT. SFC
HIGH PRESSURE SHOULD PROVIDE DRY WEATHER AND SEASONABLE TEMPS FOR
WED AND THURS.
A BUILDING RIDGE OF UPPER LEVEL HIGH PRESSURE WILL BEGIN TO WARM
THINGS UP BY FRIDAY. 12Z GEFS PUSHES 850MB TEMPS TO +1 SD BY FRI
AND KEEPS THEM THERE INTO NEXT WEEKEND.
AN ADDITIONAL CONCERN HEADING INTO NEXT WEEKEND IS THE REMNANTS
OF ISAAC. THE 12Z GEFS AND OPERATIONAL GFS BOTH TAKE WHAT IS LEFT
OF ISAAC AND CURL IT UP AND OVER THE BUILDING UPPER LEVEL RIDGE
NEXT WEEKEND....WHICH COULD TURN OUR WEATHER UNSETTLED. THE 12Z
OPERATIONAL ECMWF BRINGS THE REMNANTS OF ISAAC NORTHWARD FROM THE
GULF OF MEX INTO THE OHIO VALLEY BY THIS WEEKEND...WHERE IT
MEANDERS INTO EARLY NEXT WEEK BEFORE BEING EJECTED EASTWARD BY A
DIGGING UPPER LEVEL TROUGH.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
GRADUAL IMPROVEMENT/BINOVC CONTINUES ACRS CNTRL PA TERMINALS WITH
MVFR TO VFR CLOUD BASES GENERALLY BTWN 2-4KFT AGL. THIS TREND
WILL CONTINUE INTO THE MID-LATE AFTN AS THE BLYR CONTINUES TO
MIX...BUT EXPECT DIURNAL COOLING/INCREASING STABILITY TO ALLOW
CIGS TO LOWER AND FILL BACK IN OVERNIGHT. TSTM DEVELOPMENT HAS
INCREASED RAPIDLY SOUTH OF THE MASON-DIXON LINE...WITH CLUSTERS/BANDS
LIFTING N-NWWD FROM NRN MD/VA INTO S-CENTRAL PA. THE HIGHEST PROB
OF SHOWERS/ISOLD TSTM WILL EXIST ACRS THE SRN AIRFIELDS. HOWEVER
CONFIDENCE/TIMING ARE STILL UNCERTAIN AND THUS WILL CONTINUE TO
MENTION VCSH IN THE SRN TERMINALS.
OUTLOOK...
MON...AM LOW CIGS -SHRA EAST BCMG MVFR/VFR BY AFTN. PM SHRA/TSRA NW.
MON NGT-TUE...CFRONT PASSAGE. SHRA/TSRA POSS.
WED- THU...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ035-036-
056-057-059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...EVANEGO
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1113 PM CDT SAT AUG 25 2012
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW...
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS MAINLY THE BIG
COUNTRY THIS EVENING. I INCLUDED A TEMPO GROUP FOR THUNDER AT
KABI...AS A LINE OF THUNDERSTORMS WILL LIKELY SKIRT THE NORTHERN
PARTS OF THE CITY IN THE NEXT HOUR TO HOUR AND A HALF.
OTHERWISE...EXPECT SOUTH SOUTHEAST WINDS OF 6 TO 12 KNOTS TO
CONTINUE AT ALL TAF SITES OVERNIGHT. SCATTERED SHOWERS AND
THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE SUNDAY AFTERNOON...AND
I HAVE INCLUDED VCTS AT BOTH KABI AND KSJT...WHERE THE BEST CHANCE
OF CONVECTION EXISTS. OTHERWISE...VFR CONDITIONS WILL PREVAIL
THROUGH THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 944 PM CDT SAT AUG 25 2012/
UPDATE...
SENT A QUICK UPDATE OUT FOR THE FORECAST PACKAGE WITH MINOR
CHANGES MADE TO OVERNIGHT LOWS...WINDS AND SKY COVER.
DISCUSSION...
A COMPLEX OF WEAKLY ORGANIZED STORMS CONTINUES TO MOVE SLOWLY TO
THE EAST ACROSS THE WESTERN BIG COUNTRY...GENERALLY WEST OF A TYE
TO HASKELL LINE AS OF 930 PM. MODEST LARGE SCALE ASCENT WAS NOTED
ON THE WATER VAPOR LOOP IN RESPONSE TO A SHORTWAVE TROF OVER
SOUTHEAST NM. INSTABILITY LOOKS TO BE RATHER LIMITED...AT LEAST
BASED ON RAP DEPENDENT MESO ANALYSIS...WITH AN AREA OF MUCAPE
VALUES AROUND 1000 J/KG OVER THE AREA CURRENTLY EXPERIENCING
CONVECTION. EFFECTIVE SHEAR VALUES IN THE 25-30 KT RANGE SUGGEST
THAT MULTICELLULAR MODE MAY BE SUSTAINED FOR SEVERAL MORE
HOURS...ESPECIALLY AS THE LOW LEVEL JET DEVELOPS DURING THE
OVERNIGHT HOURS. WE COULD SEE ADDITIONAL CONVECTIVE DEVELOPMENT...
MAINLY SHOWERS...OVER THE HEARTLAND OVERNIGHT. INHERITED POPS WERE
LEFT INTACT WITH MINOR CHANGES MADE TO WINDS...SKY COVER AND
OVERNIGHT LOW TEMPS.
JOHNSON
PREV DISCUSSION... /ISSUED 603 PM CDT SAT AUG 25 2012/
DISCUSSION...
SEE AVIATION DISCUSSION BELOW...
AVIATION...
ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE AREA. I
LEFT IN A MENTION OF VCTS AT KABI...KSJT AND KBBD WHERE THE BEST
CHANCE OF SEEING A THUNDERSTORM EXISTS. BRIEF MVFR CONDITIONS WILL
BE POSSIBLE WITHIN ANY THUNDERSTORMS. MOST OF THIS ACTIVITY SHOULD
BEGIN TO DISSIPATE BY 02Z. SOUTH SOUTHEAST WINDS WILL REMAIN LIGHT
OVERNIGHT. A WEAK COLD FRONT IS FORECAST TO MOVE INTO THE NORTHERN
BIG COUNTRY SUNDAY AFTERNOON...WITH ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS DEVELOPING. I WENT AHEAD AND INCLUDED A VCTS
GROUP AFTER 19Z AT BOTH KABI AND KSJT WHERE THE BEST CHANCE OF
SEEING CONVECTION LIES. OTHERWISE...EXPECT VFR CONDITIONS TO
PREVAIL THROUGH THE NEXT 24 HOURS.
PREV DISCUSSION... /ISSUED 337 PM CDT SAT AUG 25 2012/
SHORT TERM...
CLOUD COVER ASSOCIATED FROM SHOWERS LAST NIGHT HAS LARGELY
DISSIPATED THIS AFTERNOON...AND WITH MORE SUNSHINE AND RAPIDLY
WARMING TEMPERATURES...HAVE STARTED TO SEE CONVECTION DEVELOP. SO
FAR...THE STORMS HAVE REMAINED ALONG THE WESTERN BORDER OF THE
AREA...WHERE THE MODELS HAVE SHOWN THE LOW TO MID LEVEL THETA E
AXIS TO REMAIN. GIVEN THE FAIRLY UNSTABLE...RELATIVELY UNCAPPED
AIR MASS...IN PLACE CANT REALLY RULE OUT A STORM JUST ABOUT
ANYWHERE. BUT BEST CHANCES LOOK TO BE ACROSS THE NORTHERN AND
WESTERN BIG COUNTRY...WITH THE CONVECTION EVENTUALLY SETTLING INTO
THE INTERSTATE 20 CORRIDOR THIS EVENING. THIS IDEA WELL CORRELATED
WITH THE TTU WRF AS WELL...SO SOME CONFIDENCE IN THIS SCENARIO.
WEAK FRONTAL BOUNDARY DROPS THROUGH THE PANHANDLE AND INTO THE BIG
COUNTRY BY SUNDAY AFTERNOON. CONVERGENCE WILL LIKELY BE PRETTY
WEAK...BUT AGAIN...GIVEN THE AIR MASS IN PLACE...WONT TAKE MUCH.
TTU WRF AGAIN SHOWS A FEW STORMS SUNDAY AFTERNOON ACROSS THE
AREA...MAINLY ALONG THE FRONT...WHERE THE GFS IS ALSO SHOWING THE
BEST LOW LEVEL THETA E AXIS. WILL USE THIS AS A BASIS FOR THE
SUNDAY POP FORECAST.
LONG TERM...
RETAINING SLIGHT CHANCE POPS THROUGH MONDAY. UPPER HIGH WILL BUILD
EARLY NEXT WEEK OVER COLORADO/NEW MEXICO WITH NORTH-NORTHEAST
FLOW ALOFT DEVELOPING OVER OUR AREA. THE GFS AND NAM SHOW A COUPLE
OF WEAK DISTURBANCES ALOFT MOVING DOWN INTO OUR AREA. AIRMASS
LOOKS TO REMAIN SUFFICIENTLY MOIST FOR THE POSSIBILITY OF ISOLATED
TO SCATTERED SHOWERS/THUNDERSTORMS. IN ADDITION...WITH A SURFACE
HIGH BUILDING INTO THE MIDWEST AND CENTRAL PLAINS...COULD HAVE A
WEAK COLD FRONTAL BOUNDARY SAGGING SOUTH ACROSS OUR AREA ON
MONDAY. SURFACE CONVERGENCE ALONG THIS BOUNDARY WILL BE RATHER
WEAK... HOWEVER.
THOUGH THE TIMING IS UNCERTAIN...THE 12Z MODELS INDICATE THE
POTENTIAL FOR AN ADDITIONAL DISTURBANCE ALOFT TO DROP SOUTH-
SOUTHWEST INTO OUR WEST CENTRAL TEXAS ON TUESDAY...WITH AN
ATTENDANT INCREASE IN MOISTURE/PRECIPITABLE WATER. HAVE DECIDED TO
CARRY A SLIGHT CHANCE POP IN THE EAST-CENTRAL PART OF OUR AREA FOR
TUESDAY.
DRIER AIR IS PROGGED TO WORK ITS WAY SOUTH-SOUTHWEST INTO OUR AREA
BY LATE WEDNESDAY AND REMAIN OVER OUR AREA TO THE END OF THE WEEK.
THIS WILL RESULT IN LESS CLOUD COVER ACROSS OUR AREA. WITH LIGHT
WINDS AT NIGHT...THIS SHOULD ALSO ALLOW TEMPERATURES TO DROP INTO
THE MID TO UPPER 60S FOR LOWS THURSDAY AND FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 73 93 73 93 69 / 30 30 20 20 10
SAN ANGELO 74 94 73 96 70 / 20 20 20 20 10
JUNCTION 75 93 72 95 69 / 10 10 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/99
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
138 PM EDT SUN AUG 26 2012
.SYNOPSIS...
LOW PRESSURE OVER EASTERN VIRGINIA WILL CONTINUE TO DRIFT NORTH
THIS AFTERNOON AND SLOWLY DISSIPATE. WEAK HIGH PRESSURE SHOULD
SLIDE IN BEHIND THE SYSTEM TONIGHT AND MONDAY. A COLD FRONT WILL
DROP IN FROM THE NORTHWEST TUESDAY BEFORE DRIFTING SOUTH INTO THE
CAROLINAS BY MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM EDT SUNDAY...
UPPER VORT REMAINS STUCK ACROSS THE NE CORNER OF THE AREA THIS
MORNING...BASICALLY JUST N/NW OF LYH. CLOUD CANOPY WITH THIS
FEATURE AGAIN EXPANDING BACK TO THE SW ALTHOUGH MORNING SOUNDINGS
SHOW THE DEEPER MOISTURE NOW TO THE NE WHERE BETTER INSTABILITY
AND BANDS OF SHRA PERSIST. GUIDANCE SHOWS THIS UPPER FEATURE
GRADUALLY PULLING OUT TO THE NE THIS AFTERNOON ALLOWING CLOUDS TO
DIMINISH AS DRIER AIR SWINGS IN FROM THE NW. HOWEVER STILL APPEARS
ENOUGH LOW LEVEL RH GIVEN HEATING TO PRODUCE ADDITIONAL WIDELY
SCTD BANDS OF SHRA/ISOLD TSRA PENDING OVERALL DEGREE OF HEATING.
THINK BEST CHANCE OF STORMS WILL BE ACROSS THE NW ON THE CURRENT
PERIPHERY OF THE CLOUD AXIS AND CLOSER TO THE VORT CENTER OVER THE
NE IF MORE HEATING DOES DEVELOP. LATEST LOCAL WRF AND THE HRRR DO
HAVE A FEW SHRA ACROSS THE NORTH HALF SO KEEPING SOME SCTD POPS
GOING MAINLY ALONG/NORTH OF HIWAY 460. OTRW WILL RETROGRADE
CLOUDS A BIT MORE TO THE SW INITIALLY THEN HAVE MORE OF A MOSTLY
SUNNY FLAVOR SOUTH TO PC NORTH PER LATEST NAM MOISTURE FIELDS.
TEMPS A BIT MORE TRICKY AS COULD STAY CLOSER TO THE LOW/MID 70S NE
IF CLOUDS LINGER WHILE UPPER 70S/LOW 80S LOOK ON TRACK WITH
MORNING THICKNESS ELSW.
PREVIOUS VALID DISCUSSION...
UPPER LEVEL LOW PRESSURE REMAINS OVER THE VIRGINIA PIEDMONT THIS
MORNING WITH WEAK SFC LOW UNDERNEATH IT. SHOWERS CONTINUE TO STAY
WIDELY SCATTERED AND LIGHT FROM THE SOUTHERN SHENANDOAH VALLEY
SOUTHEAST INTO SOUTHSIDE VIRGINIA.
THE 00Z MODELS ARE SIMILAR IN TAKING THE UPPER VORT/LOW NORTH TOWARD
THE DC AREA THIS AFTERNOON AND WEAKENING WHILE KEEPING SOME LOW LVL
CONVERGENCE AND SHOWER THREAT ACROSS THE NRN CWA. LEANING TOWARD
CHANCE POPS FROM THE GREENBRIER VALLEY EAST INTO OUR NRN VIRGINIA
COUNTIES...NORTH OF THE JAMES RIVER...WITH ISOLATED COVERAGE FURTHER
SOUTH AND ALONG THE BLUE RIDGE. THE NRN CWA LOOKS TO HOLD ONTO MORE
CLOUDS THROUGH THE DAY WHILE ENOUGH SUN ELSEWHERE SHOULD SEND TEMPS
A BIT WARMER THAN WHAT OCCURRED SATURDAY. WENT CLOSE TO THE LOCAL
MOS WITH LOWER 80S SOUTHEAST AND FAR SW...WITH MID TO UPPER 70S
ELSEWHERE OUTSIDE THE HIGHER ELEVATIONS.
TONIGHT...THE UPPER TROUGH/VORT CONTINUES TO WEAKEN AND SHIFT ENE
OVER THE DELMARVA. WITH LOSS OF HEATING...DO NOT FORESEE SHOWERS
LASTING MUCH PAST LATE EVENING. THE FORECAST CONCERN OVERNIGHT WILL
BE LOW LVL MOISTURE AS THE NAM KEEPS CLOUDINESS LOCKED IN ALONG THE
FOOTHILLS OF VA/NC AND LEANED TOWARD THIS IDEA. FORECAST SOUNDINGS
ARE NOT AS PREVALENT WITH THIS...SO AFTER MIDNIGHT START TO LOWER
SKY COVER MORE. FOG WILL BE AN ISSUE MONDAY MORNING AS SKIES CLEAR.
COULD SEE SOME DENSE FOG AROUND PARTICULARLY ACROSS THE BLUE
RIDGE...THE SHENANDOAH VALLEY...LYH AND GREENBRIER VALLEY. LOW TEMPS
SHOULD RANGE FROM THE MID TO UPPER 50S ACROSS THE MTNS TO LOWER TO
MID 60S EAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
AS OF 400 AM EDT SUNDAY...
HIGH PRESSURE TO BE IN CONTROL FOR THE START OF THE WORK
WEEK...1020-1022MB FINGER OF HIGH PRESSURE EXTENDING NORTH ALONG
THE SPINE OF THE APPALACHIANS. UNDER CLEAR SKIES AND LIGHT
WINDS...WILL START MONDAY OFF WITH SOME MORNING FOG...ESP THE
RIVER VALLEYS. FOG WILL THEN GIVE WAY TO PARTLY/MOSTLY SUNNY
SKIES AND WARMING TEMPS GIVEN SUBSIDENCE AND DEVELOPING SW FLOW.
THIS SHOULD PUSH HIGHS INTO THE 80S MOST SPOTS AND CLOSE TO 90 SE.
WEAK RIDGING HANGS ON THRU MUCH OF MONDAY NIGHT AS HEIGHTS ONCE
AGAIN LOWER WITH THE UPSTREAM TROF DIGGING SE TOWARD THE AREA FROM
THE OHIO VALLEY AND GREAT LAKES REGION. PRE-FRONTAL LOBE OF
DEEPER RH FOLDS INTO THE AREA FROM THE NW TUESDAY BUT HINDERED BY
DEEP WESTERLY FLOW AND WARMTH ALOFT. THINK A BAND OF SHRA/TSRA
POSSIBLE NORTH THRU TUE AFTERNOON AND ELSW DURING THE EVENING AS
FRONT SLOWLY MAKES ITS WAY ACROSS THE REGION. PENDING SOLAR
INSOLATION AHEAD OF FRONT...SHOULD BE ANOTHER WARM DAY...AND ESP
IF THERE IS A WESTERLY DOWNSLOPE COMPONENT TO THE WIND...HIGHS
AGAIN INTO THE 80S AND PERHAPS LOW 90S PIEDMONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 1210 PM EDT SATURDAY...
UPPER TROF DIGGING INTO THE AREA FROM THE NW WILL DROP A SURFACE
COLD FRONT THRU THE AREA TUESDAY NIGHT AND INTO THE CAROLINAS
WEDNESDAY. RESULTANT SHOWERS/TSRA DROPPING SE THRU THE REGION
TUESDAY EVENING DESPITE ONLY LIMITED MOISTURE AND WESTERLY FLOW.
THIS WELL IN ADVANCE OF MOISTURE ASSOCIATED WITH ISAAC THAT IS
PROGGED TO MAKE LANDFALL ALONG THE NORTHERN GULF COAST. BOUNDARY
LOOKS TO REMAIN CLOSE ENOUGH TO PROMPT ADDED SHRA/TSRA ESPCLY WITH
HEATING OVER THE SOUTH WED AFTERNOON SO CARRYING SOME CHANCE POPS
AS EAST/SE FLOW DEVELOPS NORTH OF THE FRONT.
BEYOND WEDNESDAY...FORECAST AGAIN HIGHLY DEPENDENT UPON THE TRACK OF
THE ISAAC REMNANT AND JUST HOW FAR NORTH TROPICAL MOISTURE CAN MAKE
IT GIVEN RIDGING ACROSS THE MID ATLANTIC. LATEST CONSENSUS OF THE
EARLIER EURO/GFS...AND BASED ON THE TPC TRACK IN WORKING THE SYSTEM
UP WEST OF THE MOUNTAINS INTO THE WEEKEND...SUPPORTS ONLY SCTD SHRA
COVERAGE THU-SAT AS DEEPER SE FLOW DEVELOPS. HOWEVER COULD SEE A
PERIOD OF ONLY ISOLATED SHRA MIDWEEK GIVEN SUBSIDENCE NE OF
ISAAC...PLUS DEEPER MOISTURE TRAPPED SOUTH OF THE FRONT...AND THEN
PINNED TO THE SW LATE IN THE WEEK BY RIDGING TO THE NORTH. FLOW
WEAKENS/FLATTENS QUITE A BIT BY NEXT WEEKEND...WITH THE JET LIFTING
TO THE NORTH...AND RIDGING TO THE SE WHICH COULD STALL THE REMNANT
LOW SOMEWHERE NEAR THE CENTRAL APPALACHIANS. OTRW MAINLY CHANCE POPS
THRU THE END OF THE EXTENDED WITH TEMPS CLOSE TO NORMAL
MIDWEEK...THEN WARMING INTO THE 80S MOST AREAS BY THE WEEKEND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 125 PM EDT SUNDAY...
REMNANT UPPER LOW LINGERING ACROSS THE REGION WILL CONTINUE TO
SLOWLY WEAKEN AND SHIFT EAST THIS EVENING AND OVERNIGHT. HOWEVER
PERSISTENT STRATO-CU REMAINS SLOW TO ERODE GIVEN MOISTURE ALOFT
WITH MVFR CIGS LIKELY TO CONTINUE AT TIMES FROM KROA EAST THRU
LATER THIS AFTERNOON AND PERHAPS EARLY THIS EVENING. COULD STILL
SEE -SHRA DEVELOPMENT PROVIDED SOME HEATING BUT SO ISOLATED ONLY
INCLUDING MENTION AT KROA FOR THE MOST PART.
REMAINING CU FIELDS SHOULD DISSIPATE AT SUNSET OVER THE WEST WITH
GENERALLY CLEAR SKIES THIS EVENING AND EARLY TONIGHT. OUT
EAST...BUFKIT SOUNDINGS CONTINUE TO INDICATE SOME CLOUD COVER
LINGERING OR REDEVELOPING OVERNIGHT SO LEFT IN SCATTERED LOW
CLOUDS OUTSIDE OF FOG GIVEN LOW CONFIDENCE. OTRW WITH CLEARING
SKIES...COMBINATION OF LIGHT WINDS AND GOOD RADIATIONAL CONDITIONS
TO PERMIT FORMATION OF FOG AND PERHAPS SPOTTY -DZ...ESPCLY THE RIVER
VALLEYS WITH LIFR/IFR ANTICIPATED FOR KLWB/KBCB...AND COULD ALSO
BE A PROBLEM AT KLYH AGAIN AS WELL DUE TO RECENT RAINFALL.
MORNING FOG/STRATUS MONDAY TO GIVE WAY TO WIDESPREAD VFR MONDAY
AFTERNOON WITH ONLY SOME SCTD CU AND AC AROUND.
A COLD FRONT WILL BE CROSSING THROUGH THE REGION ON TUESDAY
...ASSOCIATED WITH SCATTERED SHOWERS AND THUNDERSTORMS. ANY
IMPACT FROM TS ISAAC TO THE LOCAL REGION IS NOT ANTICIPATED UNTIL
THE LATTER HALF OF NEXT WEEK...ALTHOUGH THIS SYSTEM WILL LIKELY
IMPACT AIR TRAFFIC ROUTES TO OUR SOUTH BEFORE THEN.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...PM
LONG TERM...JH
AVIATION...JC/JH/PM/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1018 AM EDT SUN AUG 26 2012
.SYNOPSIS...
LOW PRESSURE OVER EASTERN VIRGINIA WILL CONTINUE TO DRIFT NORTH
THIS AFTERNOON AND SLOWLY DISSIPATE. WEAK HIGH PRESSURE SHOULD
SLIDE IN BEHIND THE SYSTEM TONIGHT AND MONDAY. A COLD FRONT WILL
DROP IN FROM THE NORTHWEST TUESDAY BEFORE DRIFTING SOUTH INTO THE
CAROLINAS BY MIDWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM EDT SUNDAY...
UPPER VORT REMAINS STUCK ACROSS THE NE CORNER OF THE AREA THIS
MORNING...BASICALLY JUST N/NW OF LYH. CLOUD CANOPY WITH THIS
FEATURE AGAIN EXPANDING BACK TO THE SW ALTHOUGH MORNING SOUNDINGS
SHOW THE DEEPER MOISTURE NOW TO THE NE WHERE BETTER INSTABILITY
AND BANDS OF SHRA PERSIST. GUIDANCE SHOWS THIS UPPER FEATURE
GRADUALLY PULLING OUT TO THE NE THIS AFTERNOON ALLOWING CLOUDS TO
DIMINISH AS DRIER AIR SWINGS IN FROM THE NW. HOWEVER STILL APPEARS
ENOUGH LOW LEVEL RH GIVEN HEATING TO PRODUCE ADDITIONAL WIDELY
SCTD BANDS OF SHRA/ISOLD TSRA PENDING OVERALL DEGREE OF HEATING.
THINK BEST CHANCE OF STORMS WILL BE ACROSS THE NW ON THE CURRENT
PERIPHERY OF THE CLOUD AXIS AND CLOSER TO THE VORT CENTER OVER THE
NE IF MORE HEATING DOES DEVELOP. LATEST LOCAL WRF AND THE HRRR DO
HAVE A FEW SHRA ACROSS THE NORTH HALF SO KEEPING SOME SCTD POPS
GOING MAINLY ALONG/NORTH OF HIWAY 460. OTRW WILL RETROGRADE
CLOUDS A BIT MORE TO THE SW INITIALLY THEN HAVE MORE OF A MOSTLY
SUNNY FLAVOR SOUTH TO PC NORTH PER LATEST NAM MOISTURE FIELDS.
TEMPS A BIT MORE TRICKY AS COULD STAY CLOSER TO THE LOW/MID 70S NE
IF CLOUDS LINGER WHILE UPPER 70S/LOW 80S LOOK ON TRACK WITH
MORNING THICKNESS ELSW.
PREVIOUS VALID DISCUSSION...
UPPER LEVEL LOW PRESSURE REMAINS OVER THE VIRGINIA PIEDMONT THIS
MORNING WITH WEAK SFC LOW UNDERNEATH IT. SHOWERS CONTINUE TO STAY
WIDELY SCATTERED AND LIGHT FROM THE SOUTHERN SHENANDOAH VALLEY
SOUTHEAST INTO SOUTHSIDE VIRGINIA.
THE 00Z MODELS ARE SIMILAR IN TAKING THE UPPER VORT/LOW NORTH TOWARD
THE DC AREA THIS AFTERNOON AND WEAKENING WHILE KEEPING SOME LOW LVL
CONVERGENCE AND SHOWER THREAT ACROSS THE NRN CWA. LEANING TOWARD
CHANCE POPS FROM THE GREENBRIER VALLEY EAST INTO OUR NRN VIRGINIA
COUNTIES...NORTH OF THE JAMES RIVER...WITH ISOLATED COVERAGE FURTHER
SOUTH AND ALONG THE BLUE RIDGE. THE NRN CWA LOOKS TO HOLD ONTO MORE
CLOUDS THROUGH THE DAY WHILE ENOUGH SUN ELSEWHERE SHOULD SEND TEMPS
A BIT WARMER THAN WHAT OCCURRED SATURDAY. WENT CLOSE TO THE LOCAL
MOS WITH LOWER 80S SOUTHEAST AND FAR SW...WITH MID TO UPPER 70S
ELSEWHERE OUTSIDE THE HIGHER ELEVATIONS.
TONIGHT...THE UPPER TROUGH/VORT CONTINUES TO WEAKEN AND SHIFT ENE
OVER THE DELMARVA. WITH LOSS OF HEATING...DO NOT FORESEE SHOWERS
LASTING MUCH PAST LATE EVENING. THE FORECAST CONCERN OVERNIGHT WILL
BE LOW LVL MOISTURE AS THE NAM KEEPS CLOUDINESS LOCKED IN ALONG THE
FOOTHILLS OF VA/NC AND LEANED TOWARD THIS IDEA. FORECAST SOUNDINGS
ARE NOT AS PREVALENT WITH THIS...SO AFTER MIDNIGHT START TO LOWER
SKY COVER MORE. FOG WILL BE AN ISSUE MONDAY MORNING AS SKIES CLEAR.
COULD SEE SOME DENSE FOG AROUND PARTICULARLY ACROSS THE BLUE
RIDGE...THE SHENANDOAH VALLEY...LYH AND GREENBRIER VALLEY. LOW TEMPS
SHOULD RANGE FROM THE MID TO UPPER 50S ACROSS THE MTNS TO LOWER TO
MID 60S EAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
AS OF 400 AM EDT SUNDAY...
HIGH PRESSURE TO BE IN CONTROL FOR THE START OF THE WORK
WEEK...1020-1022MB FINGER OF HIGH PRESSURE EXTENDING NORTH ALONG
THE SPINE OF THE APPALACHIANS. UNDER CLEAR SKIES AND LIGHT
WINDS...WILL START MONDAY OFF WITH SOME MORNING FOG...ESP THE
RIVER VALLEYS. FOG WILL THEN GIVE WAY TO PARTLY/MOSTLY SUNNY
SKIES AND WARMING TEMPS GIVEN SUBSIDENCE AND DEVELOPING SW FLOW.
THIS SHOULD PUSH HIGHS INTO THE 80S MOST SPOTS AND CLOSE TO 90 SE.
WEAK RIDGING HANGS ON THRU MUCH OF MONDAY NIGHT AS HEIGHTS ONCE
AGAIN LOWER WITH THE UPSTREAM TROF DIGGING SE TOWARD THE AREA FROM
THE OHIO VALLEY AND GREAT LAKES REGION. PRE-FRONTAL LOBE OF
DEEPER RH FOLDS INTO THE AREA FROM THE NW TUESDAY BUT HINDERED BY
DEEP WESTERLY FLOW AND WARMTH ALOFT. THINK A BAND OF SHRA/TSRA
POSSIBLE NORTH THRU TUE AFTERNOON AND ELSW DURING THE EVENING AS
FRONT SLOWLY MAKES ITS WAY ACROSS THE REGION. PENDING SOLAR
INSOLATION AHEAD OF FRONT...SHOULD BE ANOTHER WARM DAY...AND ESP
IF THERE IS A WESTERLY DOWNSLOPE COMPONENT TO THE WIND...HIGHS
AGAIN INTO THE 80S AND PERHAPS LOW 90S PIEDMONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 1210 PM EDT SATURDAY...
UPPER TROF DIGGING INTO THE AREA FROM THE NW WILL DROP A SURFACE
COLD FRONT THRU THE AREA TUESDAY NIGHT AND INTO THE CAROLINAS
WEDNESDAY. RESULTANT SHOWERS/TSRA DROPPING SE THRU THE REGION
TUESDAY EVENING DESPITE ONLY LIMITED MOISTURE AND WESTERLY FLOW.
THIS WELL IN ADVANCE OF MOISTURE ASSOCIATED WITH ISAAC THAT IS
PROGGED TO MAKE LANDFALL ALONG THE NORTHERN GULF COAST. BOUNDARY
LOOKS TO REMAIN CLOSE ENOUGH TO PROMPT ADDED SHRA/TSRA ESPCLY WITH
HEATING OVER THE SOUTH WED AFTERNOON SO CARRYING SOME CHANCE POPS
AS EAST/SE FLOW DEVELOPS NORTH OF THE FRONT.
BEYOND WEDNESDAY...FORECAST AGAIN HIGHLY DEPENDENT UPON THE TRACK OF
THE ISAAC REMNANT AND JUST HOW FAR NORTH TROPICAL MOISTURE CAN MAKE
IT GIVEN RIDGING ACROSS THE MID ATLANTIC. LATEST CONSENSUS OF THE
EARLIER EURO/GFS...AND BASED ON THE TPC TRACK IN WORKING THE SYSTEM
UP WEST OF THE MOUNTAINS INTO THE WEEKEND...SUPPORTS ONLY SCTD SHRA
COVERAGE THU-SAT AS DEEPER SE FLOW DEVELOPS. HOWEVER COULD SEE A
PERIOD OF ONLY ISOLATED SHRA MIDWEEK GIVEN SUBSIDENCE NE OF
ISAAC...PLUS DEEPER MOISTURE TRAPPED SOUTH OF THE FRONT...AND THEN
PINNED TO THE SW LATE IN THE WEEK BY RIDGING TO THE NORTH. FLOW
WEAKENS/FLATTENS QUITE A BIT BY NEXT WEEKEND...WITH THE JET LIFTING
TO THE NORTH...AND RIDGING TO THE SE WHICH COULD STALL THE REMNANT
LOW SOMEWHERE NEAR THE CENTRAL APPALACHIANS. OTRW MAINLY CHANCE POPS
THRU THE END OF THE EXTENDED WITH TEMPS CLOSE TO NORMAL
MIDWEEK...THEN WARMING INTO THE 80S MOST AREAS BY THE WEEKEND.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AS OF 800 AM EDT SUNDAY...
PSEUDO TROPICAL LOW ACROSS THE PIEDMONT OF VIRGINIA THIS MORNING
WILL WEAKEN AS IT SHIFTS SLOWLY NORTH...BECOMING JUST A WEAK
TROUGH BY THIS AFTERNOON. THE -RA/DZ VCNTY OF LYH/ROA MAY LINGER
INTO EARLY AFTERNOON B4 ENDING. AS SUCH...LOW IFR/MVFR CIGS TO
LINGER UNTIL DEMISE OF PRECIP...THEN CLOUD BASES EXPECTED TO LIFT
INTO VFR RANGE.
WEST OF ROA...SKIES GENERALLY CLEAR. SOME SCT-BKN CU EXPECTED TO
DEVELOP OVER THE MTNS THIS AFTERNOON...CLOUD BASES GENERALLY
3-4KFT. ANY CU THAT FORMS SHOULD DISSIPATE AT SUNSET WITH
GENERALLY CLEAR SKIES THIS EVENING AND EARLY TONIGHT. WITH
CLEARING SKIES...COMBINATION OF LIGHT WINDS AND GOOD RADIATIONAL
CONDITIONS TO PERMIT FORMATION OF FOG...ESP THE RIVER VALLEYS WITH
LIFR ANTICIPATED FOR LWB/BCB...AND COULD ALSO BE A PROBLEM AT LYH
AGAIN AS WELL DUE TO RECENT RAINFALL. WOULD NOT BE SURPRISED TO SEE LYH
WITH DENSE FOG MONDAY MORNING.
MORNING FOG MONDAY TO GIVE WAY TO WIDESPREAD VFR MONDAY AFTERNOON.
A COLD FRONT WILL BE CROSSING THROUGH THE REGION ON
TUESDAY...ASSOCIATED WITH SCATTERED SHOWERS AND THUNDERSTORMS. ANY
IMPACT FROM TS ISAAC TO THE LOCAL REGION IS NOT ANTICIPATED UNTIL
THE LATTER HALF OF NEXT WEEK...ALTHOUGH THIS SYSTEM WILL LIKELY
IMPACT AIR TRAFFIC ROUTES TO OUR SOUTH BEFORE THEN.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...PM
LONG TERM...JH
AVIATION...PM/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
227 PM CDT SUN AUG 26 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
227 PM CDT SUN AUG 26 2012
DRY CONDITIONS EXPECTED THROUGH MID WEEK WITH THE MAIN FORECAST
FOCUS BEING ON TEMPERATURES AND FOG.
CURRENTLY...A SYSTEM THAT BROUGHT RAIN AND CLOUD COVER TO THE
REGION TODAY IS SLOWLY RETREATING EAST INTO THE GREAT LAKES. RAIN
HAS COME TO AN END WITH THE UPPER LEVEL TROUGH PUSHING INTO EASTERN
WISCONSIN. THE QUESTION FOR TONIGHT IS WITH HOW FAST THE CLOUDS
CLEAR OUT AND WHETHER ANY FOG WILL DEVELOP AS IT DID ACROSS
WESTERN MINNESOTA/IOWA THIS MORNING. THE 26.18Z RAP MOISTURE
FIELDS SHOW THE DEEPER MOISTURE FIELD ASSOCIATED WITH THE TROUGH
AND RAINFALL SHIFTING EAST BY THIS EVENING. ALSO...THE STRATUS
FIELD ALONG THE WESTERN SIDE OF THE TROUGH HAS BECOME MUCH MORE
CELLULAR AND SHOULD THIN OUT THIS EVENING AND LEAD TO CLEAR SKIES
THOUGH OUT THE REGION OVERNIGHT.
WITH THESE CLEARING SKIES...LIGHT WINDS...AND A RIDGE AXIS OF
HIGH PRESSURE PUSHING IN...WILL LIKELY SEE SOME FOG FORM ACROSS
THE REGION. THE BEST CHANCES FOR WIDESPREAD AND POSSIBLY DENSE FOG
WILL BE ACROSS SOUTHERN WISCONSIN INTO EASTERN IOWA WHERE THE RAIN
AND CLOUDS HOLD ON LONGER TODAY BEFORE CLEARING OUT LATER TONIGHT.
SHOULD ALSO SEE FOG FORM IN THE MISSISSIPPI AND WISCONSIN RIVER
VALLEYS TONIGHT AS WELL THOUGH HOW WIDESPREAD IT BECOMES WILL BE
DEPENDENT UPON THE LOW LEVEL WIND FIELDS. SEE THE LATEST AVIATION
AFD FOR FURTHER/UPDATED DETAILS ON THE POTENTIAL FOR THIS VALLEY
FOG.
GOING INTO THE EARLY TO MID PORTIONS OF THE WEEK...WARMER AIR WILL
SLOWLY ADVECT INTO THE REGION FROM THE WEST AS A SURFACE RIDGE OF
HIGH PRESSURE SETTLES OVER THE UPPER MISSISSIPPI RIVER VALLEY AND
AN UPPER LEVEL RIDGE BUILDS ACROSS THE ROCKIES. WILL HAVE TO WATCH
A WARM FRONT THAT SURGES NORTHWARD TUESDAY INTO WEDNESDAY AS THE
26.12Z NAM AND GFS TRY TO PRODUCE SOME ELEVATED CONVECTION ACROSS
MINNESOTA WESTERN WISCONSIN. CONFIDENCE IS NOT HIGH THAT THIS
CONVECTION WILL OCCUR GIVEN THE DRY LOW LEVELS AND BETTER MOISTURE
TRANSPORT OFF TO THE WEST...SO HAVE KEPT THE FORECAST DRY THROUGH
THIS PERIOD BUT HAVE PUT SOME SLIGHTLY HIGHER CLOUD COVER IN OVER
THIS TIME FRAME. OTHERWISE EXPECT TEMPERATURES TO SLOWLY REBOUND
GOING INTO MID WEEK AS WARMER AIR SPILLS TO THE EAST AS THE
WESTERN RIDGE BUILDS EASTWARD INTO THE REGION WITH 850MB
TEMPERATURES CLIMBING FROM AROUND +13C ON MONDAY TO AROUND +23C BY
WEDNESDAY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
227 PM CDT SUN AUG 26 2012
THE MAIN STORY FOR THE LATER PART OF THE WEEK WITH WITH THE WARM
AIR MASS THAT WILL TAKE OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. AFTER THE WARM FRONT LIFTS NORTH OF THE REGION ON
WEDNESDAY...STRONG SOUTHERLY LOW LEVEL FLOW WILL KICK IN FROM THE
SOUTHERN PLAINS UP INTO THE GREAT LAKES AND NORTHERN PLAINS. THE
BUILDING RIDGE ACROSS THE ROCKIES WILL BEGIN TO SHIFT TO THE EAST
WEDNESDAY NIGHT INTO THURSDAY WITH THURSDAY LOOKING LIKE THE
WARMEST DAY OF THE WEEK. 850MB TEMPERATURE ANOMALIES FROM THE
26.12Z GFS AND ECMWF SHOW THAT THE +23C 850MB TEMPERATURES ARE
ABOUT 2 STANDARD DEVIATIONS ABOVE THE NORM...WHICH WOULD PUSH
RECORD HIGHS IN THE MID 90S. WITH THE WARMER AIR GRADUALLY
GETTING INTO THE REGION...HAVE GONE WITH A GRADUAL WARMING TREND
WITH THE NEAR RECORD HIGHS FOR THURSDAY. PRECIPITATION CHANCES
WILL BE MINIMAL UNTIL MAYBE NEXT WEEKEND AS A COLD FRONT DROPS
DOWN THROUGH LAKE SUPERIOR. THE 26.12Z GFS IS MORE PROGRESSIVE
WITH BRINGING THE FRONT SOUTH THROUGH THE REGION WHILE THE 26.12Z
ECMWF KEEPS THE FRONT TO THE NORTH. THE 26.12Z GFS IS ALSO ON THE
WESTERN TRACK WITH THE REMNANTS OF ISAAC COMING NORTH ALONG THE
MISSISSIPPI WHILE THE 26.12Z KEEPS IT WELL TO THE SOUTHEAST.
CONFIDENCE IS NOT VERY HIGH WITH WHERE THIS FEATURE WILL
TRACK...BUT THERE IS A BETTER CHANCE THAT IT WILL STAY TO THE
SOUTHEAST AND NOT COME INTO THE REGION. THEREFORE...HAVE KEPT THE
FORECAST MAINLY DRY THROUGH NEXT WEEKEND.
&&
.AVIATION...THROUGH 18Z MONDAY
1250 PM CDT SUN AUG 26 2012
MAIN AVIATION CONCERN WILL BE THE POSSIBILITY OF FOG DEVELOPMENT
TONIGHT..SKIES EXPECTED TO CLEAR TONIGHT AS HIGH PRESSURE BUILDS
IN FROM THE PLAINS. PRESSURE GRADIENT IS WEAK THROUGH AND GOOD
AMOUNT OF DECOUPLING IS EXPECTED WITH GENERAL LIGHT NORTHWEST FLOW
AT THE SURFACE. FAIRLY CONFIDENT THAT KRST WILL REMAIN FOG-FREE
TONIGHT WITH LIGHT/GENERALLY DRYING NORTHWEST WINDS. HOWEVER...NOT
AS CONFIDENT WITH THE KLSE TAF. NAM BUFKIT SHOWING TEMP/DEW POINT
SPREAD COLLAPSING IN THE EARLY MORNING HOURS...REACHING NEAR ZERO
BY 10-12Z. THIS WOULD SUGGEST ALMOST CERTAIN FOG. HOWEVER...NORTH-
NORTHWEST WINDS OF 5-10KT EXPECTED AT BLUFF TOP LEVEL. THIS BEING
DOWN-CHANNEL DIRECTION...NOT THINKING THIS IS REALLY CONDUCIVE FOR
WIDESPREAD RIVER VALLEY FOG...ALTHOUGH BELIEVE AT LEAST SOME
VALLEY FOG WILL BE AROUND. FOR NOW...WILL GO WITH BCFG/SCT003 AT
KLSE FROM 08-13Z AND HAVE THE EVENING SHIFT MONITOR CLOSELY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
227 PM CDT SUN AUG 26 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
638 AM CDT SUN AUG 26 2012
.SHORT TERM...THROUGH TUESDAY
234 AM CDT SUN AUG 26 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TODAY.
SURFACE ANALYSIS THIS MORNING SHOWED A WEAK AREA OF LOW PRESSURE
OVER NORTHEAST KANSAS WITH A TROUGH OF LOW PRESSURE EXTENDING
NORTHEAST INTO CENTRAL WISCONSIN. LOCAL AND REGIONAL RADARS WERE
SHOWING SHOWERS OCCURRING ALONG AND AHEAD OF THE TROUGH FROM
NORTHEAST WISCONSIN INTO WESTERN MISSOURI.
THE LAST SHORT WAVE TROUGH ASSOCIATED WITH THE REMAINS OF THE
CENTRAL ROCKIES UPPER LEVEL LOW WAS OVER EASTERN KANSAS THIS
MORNING WITH THE SURFACE LOW. THIS SHORT WAVE TROUGH IS EXPECTED
TO CONTINUE MOVING NORTHEAST TOWARD LOWER MICHIGAN TODAY. THE WEAK
AREA OF LOW PRESSURE AT THE SURFACE SHOULD TRACK SOUTH OF THE AREA
REACHING THE SOUTHERN PORTION OF LAKE MICHIGAN LATE THIS
AFTERNOON. AS THE LOW AND SHORT WAVE TROUGH PASS BY...THE FORCING
WILL BE EXITING THE AREA WITH THE 26.12Z NAM SHOWING THE WEAK
FRONTOGENESIS ALONG THE TROUGH OF LOW PRESSURE IN THE 1000-850 MB
LAYER SHIFTING EAST OF THE AREA THIS AFTERNOON AND EVENING. THE
WEAK ISENTROPIC UP GLIDE ON THE 310K SURFACE WILL PUSH OFF TO THE
EAST THIS MORNING AS WILL THE BEST MOISTURE TRANSPORT. EXPECT THE
SHOWERS TO CONTINUE MOVING EAST WITH THE BETTER FORCING WITH THE
BEST COVERAGE THIS MORNING OVER THE SOUTHEAST SECTIONS. THE
WESTERN SECTIONS OF THE FORECAST AREA ALREADY LOOK TO BE DONE AND
HAVE REMOVED THE RAIN CHANCES FOR THOSE AREAS. BY AFTERNOON...MOST
OF THE AREA SHOULD BE DRY WITH SOME LINGERING CHANCES ACROSS THE
SOUTHEAST SECTIONS.
HIGH PRESSURE WILL BUILD IN OVER THE AREA TONIGHT ALLOWING THE
SKIES TO CLEAR OUT DURING THE EVENING. THE NAM BUFKIT SOUNDING FOR
KLSE SUGGESTS A STRONG POSSIBILITY OF VALLEY FOG FORMING WITH
LIGHT WINDS UP THROUGH ABOUT 3 THOUSAND FEET AND SATURATION
OCCURRING AT THE SURFACE. IT DOES HAVE A RATHER LARGE TEMP/DEW
POINT SPREAD THIS EVENING BUT THIS SEEMS TO BE BECAUSE IT CREATES
TOO MUCH MIXING THIS AFTERNOON AND LOWERS THE DEW POINT TOO MUCH.
THE 26.04Z RAP SOUNDING DOES NOT SHOW NEARLY AS MUCH MIXING AND
DRYING THIS AFTERNOON SO MORE MOISTURE SHOULD BE IN PLACE THIS
EVENING TO AID IN THE FOG FORMATION. THE HIGH THEN LOOKS TO REMAIN
IN PLACE OVER THE REGION THROUGH TUESDAY WITH MODERATING
TEMPERATURES PUSHING DAYTIME READINGS BACK ABOVE NORMAL.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
234 AM CDT SUN AUG 26 2012
ANY RAIN CHANCES IN THE EXTENDED WILL DEPEND ON THE EVENTUAL PATH
OF TROPICAL STORM ISAAC. THE DIFFERENCES BETWEEN THE 26.00Z GFS
AND 25.12Z ECMWF ARE QUITE LARGE AND WHILE THE GFS NORMALLY DOES A
BETTER JOB OF HANDING TROPICAL SYSTEMS OVER THE OPEN
WATERS...CONFIDENCE ON HOW IT HANDLES THE SYSTEM ONCE IT IS INLAND
IS PRETTY LOW. THE UPPER LEVEL RIDGE IN PLACE AHEAD OF ISAAC
SHOULD REMAIN OVER THE MIDWEST UNTIL LATE IN THE WEEK KEEPING THE
AREA DRY. ALL THE MODELS SUGGEST A NORTHERN STREAM SYSTEM WILL
MOVE ONTO THE PACIFIC NORTHWEST COAST THURSDAY BUT THEN DIFFER ON
HOW FAST THIS MOVES EAST. THE GFS IS THE FASTEST AS IT USES THIS
SYSTEM AS THE KICKER TO RECURVE ISAAC. THE ECMWF IS MUCH SLOWER
WITH THIS SYSTEM AND FARTHER NORTH AS WELL. FOR NOW...PLAN TO
MAINTAIN CONTINUITY WITH THE PREVIOUS FORECAST AND KEEP THE
EXTENDED PERIOD DRY AND WARM.
&&
.AVIATION...TODAY AND TONIGHT
636 AM CDT SUN AUG 26 2012
FOR THIS MORNING...A BAND OF SHOWERS WILL CONTINUE TO MOVE
NORTHEAST ACROSS NORTHEAST IOWA AND SOUTHWEST AND CENTRAL
WISCONSIN. THIS PRECIPITATION HAS PRODUCED IFR TO MVFR CEILINGS
AND MVFR VISIBILITIES. THE CEILINGS MAY BECOME BRIEFLY MVFR AT
KLSE THROUGH 26.15Z. THIS IS COVERED BY A TEMPO GROUP. MEANWHILE
KRST WILL LIKELY CONTINUE TO SEE THEIR CEILING AROUND 4K FEET.
FRO THIS AFTERNOON...THE SKIES WILL GRADUALLY CLEAR. THIS SHOULD
OCCUR AT KRST AROUND 26.20Z AND AT KLSE AROUND 26.22Z.
FOR LATE TONIGHT...AREAS OF VALLEY FOG WILL LIKELY DEVELOP.
HOWEVER NOT SURE WHETHER IT WILL GET INTO KLSE. AS A RESULT...JUST
WENT WITH BCFG AFTER 27.08Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
234 AM CDT SUN AUG 26 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
234 AM CDT SUN AUG 26 2012
.SHORT TERM...THROUGH TUESDAY
234 AM CDT SUN AUG 26 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TODAY.
SURFACE ANALYSIS THIS MORNING SHOWED A WEAK AREA OF LOW PRESSURE
OVER NORTHEAST KANSAS WITH A TROUGH OF LOW PRESSURE EXTENDING
NORTHEAST INTO CENTRAL WISCONSIN. LOCAL AND REGIONAL RADARS WERE
SHOWING SHOWERS OCCURRING ALONG AND AHEAD OF THE TROUGH FROM
NORTHEAST WISCONSIN INTO WESTERN MISSOURI.
THE LAST SHORT WAVE TROUGH ASSOCIATED WITH THE REMAINS OF THE
CENTRAL ROCKIES UPPER LEVEL LOW WAS OVER EASTERN KANSAS THIS
MORNING WITH THE SURFACE LOW. THIS SHORT WAVE TROUGH IS EXPECTED
TO CONTINUE MOVING NORTHEAST TOWARD LOWER MICHIGAN TODAY. THE WEAK
AREA OF LOW PRESSURE AT THE SURFACE SHOULD TRACK SOUTH OF THE AREA
REACHING THE SOUTHERN PORTION OF LAKE MICHIGAN LATE THIS
AFTERNOON. AS THE LOW AND SHORT WAVE TROUGH PASS BY...THE FORCING
WILL BE EXITING THE AREA WITH THE 26.12Z NAM SHOWING THE WEAK
FRONTOGENESIS ALONG THE TROUGH OF LOW PRESSURE IN THE 1000-850 MB
LAYER SHIFTING EAST OF THE AREA THIS AFTERNOON AND EVENING. THE
WEAK ISENTROPIC UP GLIDE ON THE 310K SURFACE WILL PUSH OFF TO THE
EAST THIS MORNING AS WILL THE BEST MOISTURE TRANSPORT. EXPECT THE
SHOWERS TO CONTINUE MOVING EAST WITH THE BETTER FORCING WITH THE
BEST COVERAGE THIS MORNING OVER THE SOUTHEAST SECTIONS. THE
WESTERN SECTIONS OF THE FORECAST AREA ALREADY LOOK TO BE DONE AND
HAVE REMOVED THE RAIN CHANCES FOR THOSE AREAS. BY AFTERNOON...MOST
OF THE AREA SHOULD BE DRY WITH SOME LINGERING CHANCES ACROSS THE
SOUTHEAST SECTIONS.
HIGH PRESSURE WILL BUILD IN OVER THE AREA TONIGHT ALLOWING THE
SKIES TO CLEAR OUT DURING THE EVENING. THE NAM BUFKIT SOUNDING FOR
KLSE SUGGESTS A STRONG POSSIBILITY OF VALLEY FOG FORMING WITH
LIGHT WINDS UP THROUGH ABOUT 3 THOUSAND FEET AND SATURATION
OCCURRING AT THE SURFACE. IT DOES HAVE A RATHER LARGE TEMP/DEW
POINT SPREAD THIS EVENING BUT THIS SEEMS TO BE BECAUSE IT CREATES
TOO MUCH MIXING THIS AFTERNOON AND LOWERS THE DEW POINT TOO MUCH.
THE 26.04Z RAP SOUNDING DOES NOT SHOW NEARLY AS MUCH MIXING AND
DRYING THIS AFTERNOON SO MORE MOISTURE SHOULD BE IN PLACE THIS
EVENING TO AID IN THE FOG FORMATION. THE HIGH THEN LOOKS TO REMAIN
IN PLACE OVER THE REGION THROUGH TUESDAY WITH MODERATING
TEMPERATURES PUSHING DAYTIME READINGS BACK ABOVE NORMAL.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
234 AM CDT SUN AUG 26 2012
ANY RAIN CHANCES IN THE EXTENDED WILL DEPEND ON THE EVENTUAL PATH
OF TROPICAL STORM ISAAC. THE DIFFERENCES BETWEEN THE 26.00Z GFS
AND 25.12Z ECMWF ARE QUITE LARGE AND WHILE THE GFS NORMALLY DOES A
BETTER JOB OF HANDING TROPICAL SYSTEMS OVER THE OPEN
WATERS...CONFIDENCE ON HOW IT HANDLES THE SYSTEM ONCE IT IS INLAND
IS PRETTY LOW. THE UPPER LEVEL RIDGE IN PLACE AHEAD OF ISAAC
SHOULD REMAIN OVER THE MIDWEST UNTIL LATE IN THE WEEK KEEPING THE
AREA DRY. ALL THE MODELS SUGGEST A NORTHERN STREAM SYSTEM WILL
MOVE ONTO THE PACIFIC NORTHWEST COAST THURSDAY BUT THEN DIFFER ON
HOW FAST THIS MOVES EAST. THE GFS IS THE FASTEST AS IT USES THIS
SYSTEM AS THE KICKER TO RECURVE ISAAC. THE ECMWF IS MUCH SLOWER
WITH THIS SYSTEM AND FARTHER NORTH AS WELL. FOR NOW...PLAN TO
MAINTAIN CONTINUITY WITH THE PREVIOUS FORECAST AND KEEP THE
EXTENDED PERIOD DRY AND WARM.
&&
.AVIATION...THROUGH 06Z MONDAY
1148 PM CDT SAT AUG 25 2012
SOUTH TO SOUTHEASTERLY LOW LEVEL FLOW KEPT DRY AIR IN PLACE AT
BOTH TAF SITES LAST EVENING...MAINTAINING THE VFR CONDITIONS. THIS
IS DESPITE SHOWERS MOVING ACROSS ASSOCIATED WITH A LOW PRESSURE
SYSTEM LIFTING NORTHEAST OUT OF KANSAS. THESE SHOWERS ARE EXPECTED
TO PERSIST OFF AND ON AT KLSE...LIKELY TO 16Z...BEFORE THE SYSTEM
MOVES FAR ENOUGH EAST TO END THE RAIN. EVENTUALLY THE SHOWERS WILL
END UP LOWERING THE CEILING...ANTICIPATED TO DROP TO MVFR BY 12Z.
VISIBILITIES MAY DROP TO MVFR SOONER...AROUND 10Z. MEANWHILE...AT
KRST...THE CLOUDS ROOTED AT 12000-15000 FT AGL ARE SHOWING SIGNS
OF THINNING ON SATELLITE IMAGERY. IN ADDITION...THERE IS A
COLLECTION OF MVFR/IFR STRATUS SITUATED FROM NORTHWEST IOWA TO THE
TWIN CITIES...LOCATED ON/BEHIND A TROUGH OF LOW PRESSURE. ONE OF
TWO THINGS COULD HAPPEN AT KRST: 1. THE MVFR/IFR STRATUS MOVES IN
AS THE TROUGH CROSSES THE TAF SITES. 2. THE CURRENT ALTOSTRATUS
CLEARS OUT...RESULTING IN POSSIBLY DENSE FOG DEVELOPMENT DUE TO
RECENT RAIN AND HIGH AMOUNT OF SURFACE MOISTURE. FOR NOW HAVE
MAINTAINED CONTINUITY WITH THE PREVIOUS FORECAST SINCE EITHER
SCENARIO IS POSSIBLE...WITH THE IDEA OF IFR BR/STRATUS DEVELOPING
BY 10Z. GIVEN THE UNCERTAINTY...AMENDMENTS MAY BE NEEDED TO THE
KRST TAF.
THE COMBINATION OF DAYTIME HEATING AND DRIER AIR OVER THE DAKOTAS
SLOWLY MOVING EAST WILL ALLOW CONDITIONS TO TURN VFR AT BOTH TAF
SITES BY 19-20Z TODAY. VFR CONDITIONS ARE EXPECTED TO PERSIST
THROUGH THE EVENING WITH HIGH PRESSURE IN PLACE. AFTER
06Z MONDAY...VALLEY FOG APPEARS LIKELY TO FORM AT KLSE. THIS WILL
BE ADDRESSED MORE IN THE NEXT AVIATION DISCUSSION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
234 AM CDT SUN AUG 26 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS ALBANY NY
430 AM EDT TUE AUG 28 2012
.SYNOPSIS...
SHOWERS WILL END FROM WEST TO EAST THIS MORNING AS A
COLD FRONT PASSES THROUGH THE AREA. THIS FRONT WILL ALLOW FOR DRIER
WEATHER WITH PLEASANTLY MILD AFTERNOONS AND COOL NIGHTS FOR THE MID
WEEK PERIOD. WARM TEMPERATURES AND MORE HUMID CONDITIONS WILL RETURN
FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 430 AM EDT...A SHORTWAVE TROUGH WAS SITUATED OVER THE
NORTHEAST WITH A SFC COLD FRONT MOVING EASTWARD ACROSS CENTRAL
NEW YORK. A BATCH OF LIGHT TO MODERATE RAIN SHOWERS WAS AHEAD OF
THE COLD FRONT AND IMPACTING MUCH OF OUR AREA. RAINFALL RATES HAVE
GENERALLY BEEN A TENTH TO A QUARTER OF AN INCH PER HOUR...WITH
LOCALLY UP TO A THIRD OF AN INCH PER HOUR. WITHIN THE MORE HEAVIER
BURSTS...THERE HAS BEEN AN OCCASIONAL CLOUD TO GROUND LTG
STRIKE...BUT THIS HAS BEEN RATHER ISOLD FOR MUCH OF THE MORNING SO
FAR. OVER THE NEXT FEW HOURS...THIS RAINFALL WILL CONTINUE TO
SLIDE EASTWARD FROM THE HUDSON VALLEY AREA INTO WESTERN NEW
ENGLAND. WE WILL CONTINUE TO MENTION AN ISOLD TSTM OVER THE NEXT
FEW HOURS...BUT THE BULK OF THE PRECIP LOOKS TO COME IN THE FORM
OF JUST WIDESPREAD LIGHT TO MODERATE RAIN SHOWERS.
THE LATEST 3KM HRRR HAS SHOWN THESE SHOWERS ORGANIZING INTO A LINE
OF HEAVY SHOWERS/THUNDERSTORMS AS IT EXITS GOES FROM OUR NEW ENGLAND
ZONES AND HEADS INTO CENTRAL/EASTERN NEW ENGLAND FROM ABOUT
SUNRISE THROUGH THE MID MORNING HOURS. THIS SEEMS A BIT
OVERDONE...DUE TO THE TIME OF DAY AND LACK OF INSTABILITY. THE
RUC13 SHOWS MLCAPE VALUES OF 500 J/KG OR LESS ACROSS OUR
AREA...WITH HIGHER AMOUNTS ACROSS LONG ISLAND AND FAR EASTERN NEW
ENGLAND. AT THIS POINT...WE DON/T ANTICIPATE THIS ORGANZINATION OF
SHOWERS/STORMS TO HAPPEN...BUT WITH 0-6 KM BULK SHEAR VALUES OF
AROUND 40 KTS AND DEWPOINTS AROUND 70 DEGREES F...WE WILL CONTINUE
TO MONITOR RADAR TRENDS AS THE SHOWERS MOVE TOWARDS THE
BERKSHIRES/LITCHFIELD HILLS AND POINTS EASTWARD. IF THIS DOES
OCCUR...THE BIGGEST THREAT WILL BE HEAVY RAINFALL THAT CAN CAUSE
PONDING OF WATER IN URBAN OR POOR DRAINAGE AREAS.
THE FRONT SHOULD PASS THROUGH THE ENTIRE AREA BY THE MID TO LATE
MORNING HOURS...ENDING ANY THREAT FOR SHOWERS. SKIES SHOULD CLEAR
OUT AND BECOME MOSTLY SUNNY IN VALLEY AREAS DURING THE AFTN. OUR
FORECASTED MAX TEMPS ARE A MET/MAV BLEND...WITH LOW TO MID 80S FOR
VALLEY AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
DRY WEATHER IS EXPECTED ACROSS THE ENTIRE SHORT TERM PERIOD AS SFC
HIGH PRESSURE AREA MOVES FROM THE GREAT LAKES REGION TONIGHT
TOWARDS THE OHIO VALLEY FOR WEDNESDAY AND TOWARDS THE MID ATLANTIC
FOR THURSDAY INTO THURSDAY NIGHT. THIS WILL ALLOW FOR AN EXTENDED
PERIOD OF DRY CONDITIONS...WITH SUNNY TO MOSTLY SUNNY SKIES DURING
THE DAY AND CLEAR SKIES AT NIGHT. THIS SETUP WILL ALLOW FOR GOOD
RADIATIONAL COOLING AT NIGHT...AND VALLEY FOG TO DEVELOP IN THE
TYPICALLY FAVORED LOCATIONS PRIOR TO SUNRISE.
WITH THE PASSING UPPER TROUGH...TEMPS ALOFT WILL BE COOL FOR
WEDNESDAY...AND THIS WILL KEEP MAX TEMPS GENERALLY IN THE 70S AND
DEWPOINTS MAINLY IN THE 40S. MAX TEMPS SHOULD WARM UP SEVERAL
DEGREES BACK INTO THE LOW TO MIDDLE 80S FOR THURSDAY AS THE FLOW
SWITCHES AROUND TO THE SW AND ADVECTS WARMER AND SLIGHTLY MORE
HUMID AIR BACK INTO THE REGION. MIN TEMPS WILL BE CHILLY...WITH
WIDESPREAD 40S TO LOW 50S FOR BOTH TONIGHT AND WED NIGHT. A FEW
SPOTS IN THE CENTRAL ADIRONDACKS WILL EVEN DROP INTO THE 30S. MIN
TEMPS WON/T BE QUITE AS COOL FOR THURSDAY NIGHT...WITH MAINLY 50S
ACROSS THE AREA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AT THIS TIME...THERE ARE INDICATIONS THAT RIDGING MAY DOMINATE MUCH
OF THE PERIOD WITH DRY WEATHER. HOWEVER...THE EVENTUAL TRACK OF THE
REMNANTS OF ISAAC ARE UNCERTAIN AS WE HEAD THROUGH THE WEEKEND INTO
EARLY NEXT WEEK WITH A WIDE SPREAD IN MODEL SOLUTIONS. A WIDESPREAD
RAINFALL WOULD BE BENEFICIAL. PLEASE REFER TO PRODUCTS ISSUED BY THE
NATIONAL HURRICANE CENTER FOR THE OFFICIAL FORECAST TRACK FOR ISAAC
AS ITS MAKES LANDFALL AND HEADS INLAND. ALSO PLEASE REFER TO
QUANTITATIVE PRECIPITATION FORECASTS ISSUED BY THE
HYDROMETEOROLOGICAL PREDICTION CENTER FOR EXPECTED RAINFALL
ASSOCIATED WITH ISAAC AND ITS REMNANTS.
AS FOR TEMPERATURES...IT LOOKS LIKE WE WILL END AUGUST AND START
SEPTEMBER WITH ABOVE NORMAL READINGS BY AROUND 10 DEGREES. WITH A
WESTERLY FLOW EXPECTED TEMPERATURES IN THE VALLEYS MAY BE NEAR OR
JUST ABOVE 90 DEGREES ESPECIALLY IN THE MID HUDSON VALLEY. COOLER
MORE SEASONABLE TEMPERATURES ARE ANTICIPATED AS WE HEAD THROUGH THE
HOLIDAY WEEKEND.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT WILL ACROSS THE REGION THIS MORNING WITH SHOWERS AND
POSSIBLY A THUNDERSTORM. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT.
SHOWERS WILL CONTINUE TO MOVE EASTWARD ACROSS THE LOCAL AREA THIS
MORNING IMPACTING THE TAF SITES. VARIABLE CONDITIONS WITH MVFR
EXPECTED WITH THE SHOWERS WITH IFR POSSIBLE. MODEL GUIDANCE IS IN
GOOD AGREEMENT THAT THE SHOWERS WILL END EARLY THIS MORNING ACROSS
THE LOCAL AREA AND CONDITIONS WILL IMPROVE.
LIGHT TO CALM WINDS WILL BECOME WEST-NORTHWEST WITH THE FRONTAL
PASSAGE AND BECOME GUSTY THIS AFTERNOON ESPECIALLY AT KALB WITH
GUSTS OF 20 TO 25 KNOTS. WINDS WILL WEAKEN THIS EVENING AND BECOME
MORE NORTHERLY.
OUTLOOK...
TUE NIGHT-SAT...VFR.
&&
.FIRE WEATHER...
A WETTING RAINFALL OCCURRED EARLY THIS MORNING WITH SHOWERS ACROSS
THE ENTIRE AREA. SHOWERS WILL END FROM WEST TO EAST THIS MORNING
AS A COLD FRONT PASSES THROUGH THE AREA. THIS FRONT WILL ALLOW FOR
DRIER WEATHER WITH PLEASANTLY MILD AFTERNOONS AND COOL NIGHTS FOR
THE MID WEEK PERIOD. WARM TEMPERATURES AND MORE HUMID CONDITIONS
WILL RETURN FOR THE END OF THE WEEK.
RH VALUES OF NEAR 100 PERCENT EARLY THIS MORNING WILL DROP 40-50
PERCENT FOR THIS AFTERNOON. RH VALUES WILL RETURN TO NEAR 100
PERCENT WITH DEW AND FOG DEVELOPING. RH VALUES WILL BOTTOM OUT
AROUND 35 PERCENT ON WEDNESDAY AFTERNOON.
SOUTHERLY WINDS THIS MORNING WILL SWITCH TO A W-NW DIRECTION AT
10-15 MPH THIS AFTERNOON. THESE WINDS WILL DIMINISH TO NEARLY CALM
OVERNIGHT. N-NW WINDS AROUND 10 MPH ARE EXPECTED ON WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
SHOWERS WILL END THIS MORNING FROM WEST TO EAST ACROSS THE REGION
WITH THE PASSAGE OF A COLD FRONT. ALTHOUGH SOME SHOWERS EARLY THIS
MORNING MAY CONTAIN BRIEF BURSTS OF MODERATE RAINFALL...DRY
ANTECEDENT CONDITIONS WILL ALLOW FOR MUCH OF THIS RAINFALL TO BE
ABSORBED BY THE GROUND. ONLY SMALL RISES OF A FEW INCHES OR SO ARE
EXPECTED ON SMALL RIVERS AND STREAMS...WITH LARGER MAIN STEM
RIVERS HOLDING STEADY. HOWEVER...ANY AREAS THAT RECEIVE BURSTS OF
MODERATE RAINFALL MAY SEE PONDING OF WATER ON ROADWAYS OR IN AREAS
OF POOR DRAINAGE. THE THREAT FOR SHOWERS SHOULD END BY THE MID TO
LATE MORNING.
DRY WEATHER WILL RETURN THIS AFTERNOON AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER LEVELS TO HOLD STEADY
OR VERY SLOWLY FALL.
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...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
453 AM EDT TUE AUG 28 2012
.SYNOPSIS...
TROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHWARD ACROSS THE
REGION TODAY AND TONIGHT. A COLD FRONT WILL DROP SOUTHWARD
WEDNESDAY AND INTERACT WITH THE MOISTURE. THE FRONTAL BOUNDARY
WILL CONTINUE INTO THURSDAY BEFORE WEAKENING FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIS MORNING...SHOWERS CONTINUE TO MOVE NORTHWARD INTO THE REGION.
RUC13 MODELS IS SHOWING STRONG MOISTURE CONVERGENCE WITH BAND AS
IT MOVES NORTHWARD. RUC13 ALSO BRINGS A SHORT WAVE WITH THIS
CONVECTIVE ACTIVITY. LOCAL WRF MODEL SHOWS GOOD COVERAGE OF
PRECIPITATION BY 6 AM. INCREASED POPS FROM CHANCE TO LIKELY.
THIS AFTERNOON...MODELS SHOW UPPER TROUGH IN THE EAST DEEPENING.
THE SHORT WAVE MOVING NORTH REMAINS ACROSS THE REGION. DEEP
TROPICAL MOISTURE IS AVAILABLE WITH PW VALUES 2.3-2.4 INCHES.
EXPECT LOW LEVEL MOISTURE CONVERGENCE TO PRODUCE CATEGORICAL
POPS 80-100 PERCENT. HAVE 80 PERCENT RIGHT NOW BUT CONSIDERING
INCREASING CLOSER TO 100 PERCENT. INGREDIENTS ARE THERE FOR
POTENTIAL OF HEAVY RAIN. DID INCLUDE MENTION OF HEAVY RAIN
IN WEATHER GRIDS MAINLY EARLY THIS AFTERNOON. DECIDED TO LOWER
HIGH TEMPERATURES TO THE LOWER 80S BELOW GUIDANCE BECAUSE OF
HIGH POPS AND CLOUD COVER. ALSO WITH MENTION THUNDERSTORMS
THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
THE BERMUDA RIDGE CENTERED TO THE EAST WILL ALLOW FOR A LOW LEVEL
SOUTHEAST WIND FLOW TO ADVECT MORE MOISTURE TO THE REGION AND
INCREASE THE CHANCES FOR SHOWERS AND THUNDERSTORMS TONIGHT. IN
ADDITION...MODELS ARE IN GOOD AGREEMENT THAT A COLD FRONT WILL
APPROACH FROM THE NORTHWEST BY WEDNESDAY...THEN DRIFT SLOWLY SOUTH
OR STALL ACROSS THE REGION THROUGH THURSDAY. WILL KEEP FAIRLY HIGH
POPS 60-70 PERCENT TONIGHT AND WEDNESDAY. PW VALUES REMAIN HIGH AT
2.3 INCHES TONIGHT AND WEDNESDAY. ALSO VALUES WILL EXCEED 2 INCHES
THURSDAY. REASONABLE DYNAMICS WILL ALSO BE PRESENT IN THE FORM OF
THE RIGHT ENTRANCE REGION OF AN UPPER JET. THERE APPEARS TO BE
LITTLE CHANCE OF SEVERE WEATHER THROUGH THE PERIOD...HOWEVER HEAVY
RAIN WILL BE A SIGNIFICANT THREAT. HPC FIVE DAY QPF GIVES 2-4
INCHES OVER THE AREA. GUIDANCE AND LOCAL NUMBERS VERY CLOSE WITH
POPS AND TEMPERATURES THROUGH THE PERIOD. WILL STAY NEAR CONSENSUS
FOR TEMPERATURES AT AT/JUST ABOVE CONSENSUS FOR POPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNCERTAINTY REMAINS IN THE EXTENDED FORECAST AND HIGHLY DEPENDENT
ON THE EVENTUAL TRACK OF ISAAC. WILL CONTINUE WITH A MENTION OF
SHOWERS THROUGH THE EXTENDED AS MOISTURE REMAINS HIGH ACROSS THE
AREA AND THERE IS UNCERTAINTY AS TO THE MOVEMENT OF THE FRONTAL
BOUNDARY. TEMPERATURES WILL WARM BACK UP INTO THE UPPER 80S TO
NEAR 90 BY THE WEEKEND AS AN UPPER RIDGE BUILDS OVER THE AREA.
OVERNIGHT LOWS WILL BE IN THE LOWER 70S. THESE TEMPERATURES ARE
VERY CLOSE TO CLIMO FOR LATE AUGUST.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
WEAK SURFACE RIDGE OF HIGH PRESSURE JUST TO OUR NORTH...WITH TS
ISAAC TO OUR SW OVER THE CENTRAL GULF OF MEXICO. LIGHT EAST WINDS AT
THE SURFACE...WITH SOUTHERLY WINDS ABOVE THAT BRINGING IN A FETCH OF
MOISTURE AND SHALLOW ISENTROPIC LIFT LEADING TO SOME LOW CLOUDINESS
AND FOG. CONDITIONS HAVE BEEN VARIABLE...WITH LIFR AT TIMES. RADAR
INDICATES SHOWERS JUST TO OUR SOUTH...MOVING NORTH. RADAR TRENDS
PLUS GUIDANCE INDICATES THIS RAIN WILL PUSH TOWARD THE TERMINALS BY
DAYBREAK. MODELS INDICATE CATEGORICAL POPS AND PERIODS OF RAIN
THROUGHOUT MUCH OF THE DAY TUESDAY...ALONG WITH SUB VFR CIGS THROUGH
AT LEAST MUCH OF THE MORNING IF NOT INTO THE AFTERNOON. PERIODS OF
HEAVIER SHOWERS WILL REDUCE VSBYS AT TIMES AS WELL. WILL CONCENTRATE
ON THE NEAR TERM.
NOTE...VSBY MISSING FROM OBS AT OGB.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS. GOOD
CHANCE OF SHOWERS AND A FEW THUNDERSTORMS WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
145 AM EDT TUE AUG 28 2012
.SYNOPSIS...
MOISTURE WILL INCREASE FROM THE SOUTH AND EAST THROUGH TONIGHT.
A COLD FRONT WILL APPROACH THE REGION FROM THE NORTH WEDNESDAY.
THE INTERACTION BETWEEN THE FRONT AND TROPICAL MOISTURE SHOULD
INCREASE THE THREAT OF RAINFALL TUESDAY THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AREA 88DS SHOWING BAND OF SHOWERS MOVING NORTH THROUGH CHS CWA.
RUC13 SHOWS STRONG MOISTURE CONVERGENCE WITH BAND AS IT MOVES
NORTHWARD INTO REGION. ALSO RUC13 IS SHOWING A SHORT WAVE WITH
THIS CONVECTIVE ACTIVITY. LOCAL WRF MODEL SHOWS GOOD COVERAGE
OF PRECIPITATION BY 6 AM. INCREASED POPS TO 40 NORTH...60 CENTRAL
AND 80 SOUTH FOR REST OF NIGHT. LOW TEMPERATURES STILL OK. WILL
NOT MENTION THUNDER OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
TUESDAY...THE BAND OF SHOWERS CONTINUE TO MOVE NORTH DURING THE
MORNING. LOCAL WRF INDICATION GOOD COVERAGE OF PRECIPITATION AND
MOS GUIDANCE GIVING 80 PERCENT POPS AND A LITTLE HIGHER IN SOME
LOCATIONS. WILL HAVE 60-80 PERCENT ON INTO THE AFTERNOON. SOME
POPS HIGHER THAN 80 PERCENT A FEW HOURS MAINLY FROM LATE MORNING
THROUGH EARLY AFTERNOON. DURING THIS TIME DECIDED TO MENTION THE
POSSIBILITY OF HEAVY RAIN AND WILL MENTION THUNDERSTORMS FROM
LATE MORNING ON THROUGH THE DAY. DECIDED TO LOWER HIGH TEMPERATURES
INTO THE LOWER 80S EXCEPT FOR THE MIDDLE 80S IN THE CSRA.
TONIGHT THROUGH WEDNESDAY NIGHT...THE BERMUDA RIDGE CENTERED TO
THE EAST WILL ALLOW FOR A LOW LEVEL SOUTHEAST WIND FLOW TO ADVECT
MOISTURE TO THE REGION AND INCREASE THE CHANCES FOR SHOWERS AND
THUNDERSTORMS TUESDAY NIGHT. IN ADDITION...MODELS ARE IN GOOD
AGREEMENT THAT A COLD FRONT WILL APPROACH FROM THE NORTHWEST BY
WEDNESDAY...THEN DRIFT SLOWLY SOUTH OR STALL ACROSS THE REGION
THROUGH THURSDAY. THIS SCENARIO WILL FURTHER ENHANCE THE RAIN
CHANCE UP TO 60-70 PERCENT TUESDAY THROUGH WEDNESDAY. IN THE
INCREASE IN MOISTURE ACROSS THE AREA IS VERY EVIDENT IN THE MODELS
INCREASE IN PRECIPITABLE WATER VALUES ACROSS THE AREA. VALUES WILL
EXCEED 2 INCHES DURING THE PERIOD. REASONABLE DYNAMICS WILL ALSO
BE PRESENT IN THE FORM OF THE RIGHT ENTRANCE REGION OF AN UPPER
JET. THERE APPEARS TO BE LITTLE CHANCE OF SEVERE WEATHER THROUGH
THE PERIOD...HOWEVER HEAVY RAIN WILL BE A SIGNIFICANT THREAT. HPC
GUIDANCE IS INDICATES THE POTENTIAL FROM NEAR 1 INCH OF RAIN TO
THE NORTH/NORTHWEST TO AROUND 2 INCHES OR MORE ACROSS THE CENTRAL
SAVANNAH RIVER AREA AND EASTERN MIDLANDS. GUIDANCE AND LOCAL
NUMBERS VERY CLOSE WITH POPS AND TEMPERATURES THROUGH THE PERIOD.
WILL STAY NEAR CONSENSUS FOR TEMPERATURES AT AT/JUST ABOVE
CONSENSUS FOR POPS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
UNCERTAINTY REMAINS IN THE EXTENDED FORECAST AND HIGHLY DEPENDENT
ON THE EVENTUAL TRACK OF ISAAC. WILL CONTINUE WITH A MENTION OF
SHOWERS THROUGH THE EXTENDED AS MOISTURE REMAINS HIGH ACROSS THE
AREA AND THERE IS UNCERTAINTY AS TO THE MOVEMENT OF THE FRONTAL
BOUNDARY. TEMPERATURES WILL WARM BACK UP INTO THE UPPER 80S TO
NEAR 90 BY THE WEEKEND AS AN UPPER RIDGE BUILDS OVER THE AREA.
OVERNIGHT LOWS WILL BE IN THE LOWER 70S. THESE TEMPERATURES ARE
VERY CLOSE TO CLIMO FOR LATE AUGUST.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
WEAK SURFACE RIDGE OF HIGH PRESSURE JUST TO OUR NORTH...WITH TS
ISAAC TO OUR SW OVER THE CENTRAL GULF OF MEXICO. LIGHT EAST WINDS AT
THE SURFACE...WITH SOUTHERLY WINDS ABOVE THAT BRINGING IN A FETCH OF
MOISTURE AND SHALLOW ISENTROPIC LIFT LEADING TO SOME LOW CLOUDINESS
WITH IFR TO MVFR CIGS CURRENTLY. RADAR INDICATES A BAND OF SHOWERS
TO OUR SOUTH ACROSS SE GA...LOWER SC AND OFFSHORE...MOVING NORTH.
RADAR TRENDS PLUS GUIDANCE INDICATES THIS RAIN WILL PUSH TOWARD THE
TERMINALS BY DAYBREAK. MODELS INDICATE CATEGORICAL POPS AND PERIODS
OF RAIN THROUGHOUT MUCH OF THE DAY TUESDAY...ALONG WITH SUB VFR CIGS
THROUGH AT LEAST MUCH OF THE MORNING IF NOT INTO THE AFTERNOON.
PERIODS OF HEAVIER SHOWERS WILL REDUCE VSBYS AT TIMES AS WELL. WILL
CONCENTRATE ON THE NEAR TERM.
NOTE...VSBY MISSING FROM OBS AT OGB.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS. GOOD
CHANCE OF SHOWERS AND A FEW THUNDERSTORMS WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
510 AM EDT TUE AUG 28 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 502 AM EDT TUE AUG 28 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE SRN/CNTRL ROCKIES INTO THE CNTRL PLAINS AND A TROUGH OVER NE
CANADA RESULTING IN NW FLOW THROUGH THE UPPER GREAT LAKES. AT THE
SFC...HIGH PRES EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR
INTO NRN WI. IR LOOP SHOWED THAT NRLY FLOW HAS BROUGHT SOME PATCHY
CLOUDS INTO UPPER MI WHILE MORE EXTENSIVE CLOUDS REMAINED NORTH OF
LAKE SUPERIOR.
TODAY...MODELS SUGGEST THAT ENOUGH MOISTURE WILL LINGER OVER THE
AREA SO THAT DAYTIME HEATING/MIXING WILL SUPPORT SCT-BKN CU BENEATH
A STRENGTHENING INVERSION AROUND 800 MB. 850 MB TEMPS IN THE 10C TO
12C RANGE WILL SUPPORT MAX READINGS IN THE MID TO UPPER 70S INLAND.
A WEAK GRADIENT WILL ALLOW LAKE BREEZES TO DEVELOP DURING THE
AFTERNOON KEEPING TEMPS CLOSER TO 70 ALONG LAKE SUPERIOR.
TONIGHT...WITH HIGH PRES BUILDING INTO ERN UPPER MI AND LOWER
MI...WEAK SRLY FLOW WILL DEVELOP. HOWEVER...WINDS SHOULD REMAIN
DECOUPLED AND ALLOW DECENT RADIATIONAL COOLING WITH INLAND MIN TEMPS
DROPPING TO AROUND 50.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 502 AM EDT TUE AUG 28 2012
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS AN UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AND HEIGHT RISES
AHEAD OF THIS SYSTEM...850MB TEMPS INCREASE TO AROUND 20C W AND 16C
E BY 00Z THU AS A IMPRESSIVE EML MOVES INTO THE AREA. 850MB TEMPS
START THE DAY A GOOD 5-6C COOLER...SO WE SHOULD NOT BE ABLE TO
ACHIEVE THE FULL POTENTIAL OF THE 20-16C 850MB TEMPS...ESPECIALLY
SINCE WE MAY NOT MIX AS HIGH AS THE WARMEST TEMPERATURES ALOFT.
HIGHS WED SHOULD BE IN THE MID 80S TO AROUND 90 WEST HALF...AND IN
THE MID 70S TO MID 80S EAST HALF. WARMEST TEMPS FAR WEST AND COOLEST
DOWN WIND OF LAKE MICHIGAN WITH A SSW WIND. LOW LEVEL MOISTURE
CONTINUES TO VARY BETWEEN MODELS...WITH THE 00Z/28 GFS BEING ON THE
HIGH SIDE /1000-700MB RH STILL UNDER 60 PERCENT/ AND THE 00Z/28 NAM
ON THE LOW SIDE /LESS THAN 45 PERCENT 1000-700MB RH/. USING A MORE
MODERATED BLEND OF THE TWO ALONG WITH OTHER MIDDLE OF THE ROAD
GUIDANCE...CONDITIONS WILL LEAD TO MIN SFC RH VALUES OF 30 TO 45
PERCENT. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH GUSTS OF
15-20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE PEAK OF THE EML
MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. MODEL
GUIDANCE VARIES WITH 850MB TEMPS BETWEEN 22C-26C. HIGH TEMPS IN THE
80S TO MID 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN/. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC TROUGH
MOVES TO JUST W OF THE CWA BY 00Z FRI. SW SFC WINDS WILL BE AROUND
15KTS WITH GUSTS AS HIGH AS 30-35KTS POSSIBLE. TEMPERATURES AND MORE
SO WINDS WILL BE HIGHLY DEPENDENT ON HOW HIGH WE CAN MIX. MOST
MODELS SHOW US MIXING TO AROUND 850MB...WHERE THEY HAVE WINDS OF
AROUND 35KTS. MODELS ALSO AGREE IN SHOWING ERN UPPER MI SEEING
INCREASED 850MB WINDS...SO IT MAY VERY WELL BE GUSTIER THERE. GALE
POTENTIAL WILL NEED TO BE MONITORED OVER LAKE MI NEARSHORE
ZONES...BUT GIVEN STRONG WAA IT APPEARS LESS LIKELY. VERY DRY
MID/LOW LEVELS WILL AGAIN LEAD TO MIN SFC RH GENERALLY IN THE 30-40
PERCENT RANGE /EXCEPT HIGHER IN THE 40-50 PERCENT RANGE DOWNWIND OF
LAKE MICHIGAN/...SO FIRE WEATHER CONCERNS WILL BE MORE ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI STILL LOOK ABOVE NORMAL AS
MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL WINDS.
TEMPS SAT LOOK A FEW OF DEGREES COOLER THAN FRI. MODELS THEN SHOW A
STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY THROUGH
MON...BUT WITH MODELS INHERENT INABILITY TO FORECAST TROPICAL
SYSTEMS...CONFIDENCE DECREASES SHARPLY AS THE REMNANTS OF ISAAC ARE
FORECAST TO BE S OF OR ENCROACHING UPON THE CWA LATE SAT THROUGH
SUN. THE FORECAST FOR SUN AND MON WILL BE HIGHLY DEPENDENT ON WHERE
MOISTURE FROM ISAAC ENDS UP...SO WILL NOT HAVE TOO HIGH OF POPS AND
WILL GO WITH CONSENSUS OF MODELS AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE AUG 28 2012
HIGH PRESSURE TO CONTINUE TO BUILD INTO THE REGION...RESULTING IN
VFR CONDITIONS THROUGH THE FORECAST. SOME PATCHY FOG MAY DEVELOP IN
LOW AREAS AS LIGHT WINDS PERSIST THROUGH THE NIGHT BUT AT THIS TIME
DO NOT EXPECT ANY IMPACTS TO ANY OF THE AVIATION SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT TUE AUG 28 2012
QUIET CONDITIONS OVER THE MARINE AREAS THROUGH WEDNESDAY AS HIGH
PRESSURE BUILDS OVER THE GREAT LAKES REGION WITH LIGHT WINDS
EXPECTED. SOUTHWESTERLY WINDS WILL STRENGTHEN BY WEDNESDAY NIGHT AND
THURSDAY AHEAD OF A LOW PRESSURE SYSTEM OVER ONTARIO. HOWEVER...WITH
INCREASING STABILITY IN THE WAA REGIME WINDS ARE EXPECTED TO REMAIN
IN THE 15 TO 25 KT RANGE OVER THE SE HALF OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...RJT
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
503 AM EDT TUE AUG 28 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 502 AM EDT TUE AUG 28 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE SRN/CNTRL ROCKIES INTO THE CNTRL PLAINS AND A TROUGH OVER NE
CANADA RESULTING IN NW FLOW THROUGH THE UPPER GREAT LAKES. AT THE
SFC...HIGH PRES EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR
INTO NRN WI. IR LOOP SHOWED THAT NRLY FLOW HAS BROUGHT SOME PATCHY
CLOUDS INTO UPPER MI WHILE MORE EXTENSIVE CLOUDS REMAINED NORTH OF
LAKE SUPERIOR.
TODAY...MODELS SUGGEST THAT ENOUGH MOISTURE WILL LINGER OVER THE
AREA SO THAT DAYTIME HEATING/MIXING WILL SUPPORT SCT-BKN CU BENEATH
A STRENGTHENING INVERSION AROUND 800 MB. 850 MB TEMPS IN THE 10C TO
12C RANGE WILL SUPPORT MAX READINGS IN THE MID TO UPPER 70S INLAND.
A WEAK GRADIENT WILL ALLOW LAKE BREEZES TO DEVELOP DURING THE
AFTERNOON KEEPING TEMPS CLOSER TO 70 ALONG LAKE SUPERIOR.
TONIGHT...WITH HIGH PRES BUILDING INTO ERN UPPER MI AND LOWER
MI...WEAK SRLY FLOW WILL DEVELOP. HOWEVER...WINDS SHOULD REMAIN
DECOUPLED AND ALLOW DECENT RADIATIONAL COOLING WITH INLAND MIN TEMPS
DROPPING TO AROUND 50.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 502 AM EDT TUE AUG 28 2012
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS AN UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AND HEIGHT RISES
AHEAD OF THIS SYSTEM...850MB TEMPS INCREASE TO AROUND 20C W AND 16C
E BY 00Z THU AS A IMPRESSIVE EML MOVES INTO THE AREA. 850MB TEMPS
START THE DAY A GOOD 5-6C COOLER...SO WE SHOULD NOT BE ABLE TO
ACHIEVE THE FULL POTENTIAL OF THE 20-16C 850MB TEMPS...ESPECIALLY
SINCE WE MAY NOT MIX AS HIGH AS THE WARMEST TEMPERATURES ALOFT.
HIGHS WED SHOULD BE IN THE MID 80S TO AROUND 90 WEST HALF...AND IN
THE MID 70S TO MID 80S EAST HALF. WARMEST TEMPS FAR WEST AND COOLEST
DOWN WIND OF LAKE MICHIGAN WITH A SSW WIND. LOW LEVEL MOISTURE
CONTINUES TO VARY BETWEEN MODELS...WITH THE 00Z/28 GFS BEING ON THE
HIGH SIDE /1000-700MB RH STILL UNDER 60 PERCENT/ AND THE 00Z/28 NAM
ON THE LOW SIDE /LESS THAN 45 PERCENT 1000-700MB RH/. USING A MORE
MODERATED BLEND OF THE TWO ALONG WITH OTHER MIDDLE OF THE ROAD
GUIDANCE...CONDITIONS WILL LEAD TO MIN SFC RH VALUES OF 30 TO 45
PERCENT. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH GUSTS OF
15-20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE PEAK OF THE EML
MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. MODEL
GUIDANCE VARIES WITH 850MB TEMPS BETWEEN 22C-26C. HIGH TEMPS IN THE
80S TO MID 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN/. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC TROUGH
MOVES TO JUST W OF THE CWA BY 00Z FRI. SW SFC WINDS WILL BE AROUND
15KTS WITH GUSTS AS HIGH AS 30-35KTS POSSIBLE. TEMPERATURES AND MORE
SO WINDS WILL BE HIGHLY DEPENDENT ON HOW HIGH WE CAN MIX. MOST
MODELS SHOW US MIXING TO AROUND 850MB...WHERE THEY HAVE WINDS OF
AROUND 35KTS. MODELS ALSO AGREE IN SHOWING ERN UPPER MI SEEING
INCREASED 850MB WINDS...SO IT MAY VERY WELL BE GUSTIER THERE. GALE
POTENTIAL WILL NEED TO BE MONITORED OVER LAKE MI NEARSHORE
ZONES...BUT GIVEN STRONG WAA IT APPEARS LESS LIKELY. VERY DRY
MID/LOW LEVELS WILL AGAIN LEAD TO MIN SFC RH GENERALLY IN THE 30-40
PERCENT RANGE /EXCEPT HIGHER IN THE 40-50 PERCENT RANGE DOWNWIND OF
LAKE MICHIGAN/...SO FIRE WEATHER CONCERNS WILL BE MORE ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI STILL LOOK ABOVE NORMAL AS
MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL WINDS.
TEMPS SAT LOOK A FEW OF DEGREES COOLER THAN FRI. MODELS THEN SHOW A
STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY THROUGH
MON...BUT WITH MODELS INHERENT INABILITY TO FORECAST TROPICAL
SYSTEMS...CONFIDENCE DECREASES SHARPLY AS THE REMNANTS OF ISAAC ARE
FORECAST TO BE S OF OR ENCROACHING UPON THE CWA LATE SAT THROUGH
SUN. THE FORECAST FOR SUN AND MON WILL BE HIGHLY DEPENDENT ON WHERE
MOISTURE FROM ISAAC ENDS UP...SO WILL NOT HAVE TOO HIGH OF POPS AND
WILL GO WITH CONSENSUS OF MODELS AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE AUG 28 2012
HIGH PRESSURE TO CONTINUE TO BUILD INTO THE REGION...RESULTING IN
VFR CONDITIONS THROUGH THE FORECAST. SOME PATCHY FOG MAY DEVELOP IN
LOW AREAS AS LIGHT WINDS PERSIST THROUGH THE NIGHT BUT AT THIS TIME
DO NOT EXPECT ANY IMPACTS TO ANY OF THE AVIATION SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 502 AM EDT TUE AUG 28 2012
QUIET CONDITIONS OVER THE MARINE AREAS THROUGH WEDNESDAY AS HIGH
PRESSURE BUILDS OVER THE GREAT LAKES REGION WITH LIGHT WINDS
EXPECTED. SOUTHWESTERLY WINDS WILL STRENGTHEN BY WEDNESDAY NIGHT AND
THURSDAY AHEAD OF A LOW PRESSURE SYSTEM OVER ONTARIO. BY LATE
THURSDAY/THURSDAY NIGHT THIS MAY BRING WIND GUSTS OVER NORTHWESTERN
LAKE MICHIGAN AND NORTHERN GREEN BAY OVER 30KTS. WHILE SOME GALE
FORCE GUSTS ARE NOT OUT OF THE QUESTION...IT IS NOT THE MOST LIKELY
SCENARIO AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...RJT
MARINE...JLB
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
459 AM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 459 AM CDT/
FIRE WEATHER CONCERNS AT THE FOREFRONT TODAY...THOUGH IN THE
IMMEDIATE TERM WATCHING SOME ELEVATED THUNDERSTORMS WORK THEIR WAY
INTO NORTHWEST PARTS OF THE CWA. GREATER COVERAGE/INTENSITY STORMS
EXPECTED TO REMAIN NORTH AND NORTHEAST OF OUR FORECAST AREA IN AREA
OF STRONG MID LEVEL THETA-E ADVECTION WHICH IS PROGGED TO EXTEND
FROM FAR NORTHEAST SD/FAR SOUTHEAST ND INTO CENTRAL/SOUTHEAST MN
THIS MORNING. THAT SAID...WEAKER EXTENSION OF THETA-E ADVECTION
AHEAD OF COMPACT MID LEVEL WAVE WILL MOVE ACROSS OUR FORECAST AREA
THIS MORNING AND WILL TRACK 20-30 PERCENT POPS EASTWARD THROUGH 18Z.
DO NOT EXPECT MUCH RAINFALL TO REACH THE GROUND WITH THESE STORMS AS
SUB CLOUD LAYER IS QUITE DRY. HOWEVER...LIGHTNING THREAT IS THERE
AND AS SUCH FEEL ISOLATED MENTION IS WARRANTED.
TEMPERATURES TRICKIEST PART OF THE NEXT FEW DAYS...AS MODELS STILL
WILDLY DIVERGENT IN THEIR LOW LEVEL TEMPERATURE/MOISTURE PROFILES.
HOWEVER WARMER/DRIER NAM...ALTHOUGH IT SEEMS OVERLY MIXED AND WAY
TOO WARM IN ITS 2 METER TEMPERATURE FORECAST...HAS BETTER SUPPORT
FROM ECMWF/GEM IN 850/925MB TEMPERATURES...AND THUS HEDGING TOWARD
WARMER SIDE OF FORECAST TEMPERATURE GUIDANCE SEEMS THE WAY TO GO IN
THIS PATTERN. WITH THIS...HAVE NUDGED TEMPERATURES UP A LITTLE MORE
FROM PREVIOUS FORECAST FOR WEDNESDAY/THURSDAY. FORTUNATELY HUMIDITY
LEVELS EXPECTED TO REMAIN IN CHECK...AS DEEP MIXING NEEDED TO
ACHIEVE THE HOT TEMPERATURES WILL ALSO MIX DOWN DRIER AIR. WHILE
THIS IS GOOD NEWS AS FAR AS LIMITING NEED FOR HEAT ADVISORIES...IT
DOES PRODUCE SIGNIFICANT FIRE WEATHER CONCERNS AS ALLUDED TO ABOVE.
THIS IS DISCUSSED IN MUCH GREATER DETAIL IN FIRE WEATHER SECTION
OF THIS PRODUCT. HOWEVER...IN SHORT...GUSTY SOUTH WINDS AND LOW
AFTERNOON HUMIDITY LEVELS HAVE PROMPTED ISSUANCE OF RED FLAG WARNING
FOR THE LOWER JAMES/BIG SIOUX VALLEYS AND EXTREME NORTHEAST NEBRASKA
THIS AFTERNOON. FIRE WEATHER WATCH ALSO ISSUED FOR THESE AREAS...
ALONG WITH THE LOWER BRULE AREA IN SOUTH CENTRAL SD...FOR WEDNESDAY
AFTERNOON/EARLY EVENING. ALTHOUGH NO HEADLINES HAVE YET BEEN ISSUED
FOR THURSDAY...EXPANSION OF VERY HIGH/EXTREME FIRE DANGER AND
POTENTIAL RED FLAG CONDITIONS IS EXPECTED AND WILL WATCH THIS PERIOD
CLOSELY FOR HEADLINES OVER THE NEXT 12-24 HOURS.
LONGER RANGE SEES REMNANTS OF ISAAC PROGGED TO LIFT NORTH THROUGH
THE NATIONS MIDSECTION FRIDAY/SATURDAY...THEN TURNING EASTWARD BUT
LINGERING OVER THE WESTERN OHIO VALLEY INTO SUNDAY/MONDAY. WILL NOT
SEE ANY RAIN IN THIS AREA FROM THE ISAAC REMNANTS. HOWEVER...WILL
HAVE AN EFFECT IN SLOWING ANY POTENTIAL SOUTHEASTWARD PUSH OF COOL
FRONT WHICH IS FORECAST TO MOVE INTO OUR AREA LATE IN THIS FORECAST
PERIOD. THIS WILL RESULT IN PERSISTENCE OF WELL ABOVE NORMAL
TEMPERATURES RIGHT THROUGH THE LABOR DAY HOLIDAY. FRIDAY/SATURDAY
SHOULD BE WARMEST DAYS OF THE LONGER RANGE...THOUGH SHOULD BE COOLER
THAN MIDWEEK AS THERMAL RIDGE BREAKS TOWN AS THE THURSDAY/THURSDAY
NIGHT FRONT WASHES OUT. THUS HAVE TEMPERED HIGHS INTO THE UPPER 80S
TO MID 90S...WITH COOLEST READINGS LIKELY TO BE IN SOUTHEAST CWA ON
SATURDAY AS FLOW BEGINS TO PULL A LITTLE COOLER AIR OUT OF ISAAC
REMNANTS AS THEY MOVE INTO MISSOURI/SOUTHEAST IOWA. WITH NEXT COOL
FRONT SET TO MOVE IN SUNDAY/MONDAY TIME FRAME...COULD SEE POTENTIAL
FOR SHOWERS/THUNDERSTORMS SOME DURING THIS PERIOD. HOWEVER...OPTED
TO KEEP THE PERIOD DRY FOR NOW UNTIL MODELS GET A BETTER HANDLE ON
REMNANTS OF ISAAC AND EFFECT OF THAT ON FRONTAL TIMING.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THROUGH THE ENTIRE FORECAST PERIOD.
ISOLATED LIGHT SHOWERS WITH PERHAPS A RUMBLE OF THUNDER WILL
SLIDE THROUGH AREAS NORTH OF INTERSTATE 90 OVERNIGHT AND EARLY
THIS MORNING...BUT CEILINGS AND VISIBILITIES ALMOST CERTAIN TO
REMAIN VFR EVEN IN MORE INTENSE. /CHAPMAN
&&
.FIRE WEATHER...
SUBTLE LOW LEVEL BOUNDARY TRAILING SOUTHWESTWARD FROM THE MID LEVEL
WAVE WILL DRIFT TOWARD WESTERN EDGE OF THE CWA THIS AFTERNOON. THIS
WILL LIMIT FIRE DANGER FOR THE MIDDLE JAMES/LOWER BRULE AREAS TODAY.
HOWEVER...LOW RELATIVE HUMIDITY LEVELS WILL STILL CREATE HIGH TO
VERY HIGH DANGER IN THESE AREAS. GREATER CONCERN FOR TODAY IS FROM
THE LOWER JAMES/LOWER BIG SIOUX VALLEY AREAS INTO EXTREME NORTHEAST
NEBRASKA. THIS FAR ENOUGH REMOVED FROM THE BOUNDARY THAT SOUTHERLY
GUSTS IN EXCESS OF 25 MPH ARE LIKELY WITH MIXING THIS AFTERNOON. THE
DEEP MIXING EXPECTED TO BRING DOWN SOME OF THE DRIER AIR EVIDENT ON
THE 28/00Z LBF RAOB LAST EVENING. NAM AND TO SOME EXTENT HRRR SEEM
TO CAPTURE THIS IDEA BEST AND HAVE LEANED CLOSER TO THESE MODELS FOR
DROPPING DEW POINTS WITH AFTERNOON MIXING. THIS RESULTS IN MINIMUM
HUMIDITY LEVELS OF 20-25 PERCENT IN THE CONCERN AREA THIS AFTERNOON
AND HAVE ISSUED A RED FLAG WARNING FOR THESE TWO FIRE WEATHER ZONES
TODAY.
WEDNESDAY A LITTLE MORE UNCERTAIN...AS THAT WEAK BOUNDARY FORECAST
TO PUSH INTO THE SOUTHERN CWA TONIGHT BEFORE STALLING AND LIFTING
SLOWLY BACK TO THE NORTH ON WEDNESDAY. QUESTION WILL BE WHETHER IT
WILL SHIFTS NORTH EARLY ENOUGH TO ALLOW STRONGER SOUTH WINDS TO MIX
DOWN THROUGH THE MISSOURI RIVER VALLEY AREAS. RELATIVE HUMIDITY FROM
SOUTH CENTRAL SD...THROUGH THE MISSOURI VALLEY INTO THE SIOUX CITY
AREA CERTAINLY WORTHY OF HEIGHTENED FIRE WATCH...AS ALL MODELS
EXCEPT GFS INDICATE AFTERNOON DEW POINTS MIXING DOWN INTO THE 40S...
RESULTING IN MINIMUM HUMIDITY VALUES BELOW 20 PERCENT. GIVEN LOWER
CONFIDENCE IN WEDNESDAY AFTERNOON WIND FORECAST...NOT COMFORTABLE
WITH A DAY 2 RED FLAG WARNING JUST YET. HOWEVER HAVE ISSUED A FIRE
WEATHER WATCH FOR THE AREAS OF CONCERN.
DESPITE ALL OF THE ABOVE...THURSDAY PRESENTS GREATEST FIRE WEATHER
CONCERN AT THIS POINT. NORTHERN STREAM WAVE TOPPING THE BROAD UPPER
RIDGE WILL DRAG A COOL FRONT INTO THE NORTHWEST 1/3 OF THE CWA BY
THURSDAY AFTERNOON. DEEP SOUTHWEST FLOW WITHIN LOW LEVEL JET AHEAD
OF THIS BOUNDARY WILL ALLOW FOR WIDESPREAD 20-25 MPH SUSTAINED WINDS
WITH GUSTS OF 30-35 MPH LIKELY OVER MUCH OF THE CWA. THIS ALONG WITH
STRONG THERMAL RIDGE AHEAD OF BOUNDARY COULD RESULT IN NEAR RECORD
HIGHS AROUND 100 DEGREES...AND DEW POINTS MIXING INTO THE 40S...WILL
AGAIN PRODUCE MINIMUM HUMIDITY VALUES BELOW 20 PERCENT IN SOUTHWEST
TO NORTHEAST CORRIDOR THROUGH THE CENTER OF THE CWA...LAKE ANDES AND
YANKTON...THROUGH SIOUX FALLS...INTO SOUTHWEST MN. GIVEN THE MORE
IMMEDIATE FIRE DANGER THE NEXT COUPLE OF DAYS...HAVE HELD OFF
ISSUING ANY HEADLINE FOR THURSDAY JUST YET...BUT WILL CERTAINLY
HIGHLIGHT VERY HIGH TO EXTREME FIRE DANGER IN THE HAZARDOUS WEATHER
OUTLOOK AND DAY SHIFT WILL WANT TO COORDINATE POTENTIAL HEADLINES
WITH AFFECTED FIRE OFFICIALS FOR POSSIBLE ISSUANCE THIS AFTERNOON OR
WEDNESDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR NEZ249.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ249.
SD...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR SDZ258.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR SDZ255-258.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
350 AM CDT TUE AUG 28 2012
.SHORT TERM...TODAY THROUGH THURSDAY
345 AM CDT TUE AUG 28 2012
AT 3 AM...STILL HAVE NOT SEEN MUCH VALLEY FOG DEVELOPING ACROSS
THE FORECAST AREA. THERE IS A LITTLE HAZE HANGING OVER THE
CITY...BUT NO SIGNS OF A STRATUS DECK DEVELOPING YET. IN ADDITION
THERE IS STILL A SLIGHT BREEZE HERE AT THE OFFICE AND A 3 TO
4 DEGREE TEMPERATURE/DEW POINT SPREAD ALONG THE MISSISSIPPI RIVER.
THEY HAVE FALLEN TO LESS TO AROUND 1 DEGREE SPREAD IN WISCONSIN
RIVER AND JUST IN THE PAST HOUR BOSCOBEL HAS CAME IN WITH A 1 1/2
MILE VISIBILITY DUE TO FOG. WITH THE RAP BUFKIT SOUNDINGS CONTINUING
TO SHOW A 10 TO 15 KNOT WIND IN THE LOWEST 1 KM AND THE 925 MB VAD
WIND PROFILERS ALSO SHOWING 10 TO 15 KNOT WINDS...BEGINNING TO
WONDER WHETHER THE VALLEY FOG WILL DEVELOP. DUE TO THIS...REDUCED
THE WIDESPREAD VALLEY FOG TO JUST AREAS OF VALLEY FOG.
FURTHER TO THE NORTHWEST...A CLUSTER OF SHOWERS AND THUNDERSTORMS
WERE DEVELOPING ACROSS SOUTHEAST NORTH DAKOTA AND NORTH CENTRAL
SOUTH DAKOTA. THIS PRECIPITATION IS ASSOCIATED WITH 850 TO 600 MB
WARM AIR ADVECTION AHEAD OF A SHORT WAVE TROUGH. BOTH THE MESO
MODELS AND OPERATIONAL MODELS ARE IN AGREEMENT THAT THIS AREA WILL
GRADUALLY WEAKEN AS IT MOVES SOUTHEAST TOWARD THE AREA THIS
AFTERNOON. WHILE THE 0-6 KM SHEAR IS GREATER THAN 40 KNOTS...THE
BUFKIT SOUNDINGS SHOW THAT THE SHEAR THAT ANY ELEVATED THUNDERSTORMS
WOULD FEEL WILL BE GENERALLY LESS THAN 10 KNOTS. EVEN THE DCAPE IS
NOT THAT IMPRESSIVE WITH VALUES GENERALLY LESS 500 J/KG. AS A
RESULT...NOT TOO CONCERNED WITH ANY OF THESE THUNDERSTORMS
BECOMING SEVERE.
TONIGHT AND WEDNESDAY MORNING - THE MODELS CONTINUE TO SHOW THAT
YET ANOTHER SHORT WAVE TROUGH WILL BE ROUNDING THE UPPER LEVEL
RIDGE. WEAK TO MODERATE 850 MB TO 600 MB MOISTURE TRANSPORT AND
WARM AIR ADVECTION WILL LIKELY LEAD TO THE DEVELOPMENT OF ISOLATED
SHOWERS AND THUNDERSTORMS. WHILE THE MOISTURE TRANSPORT CONTINUES
INTO WEDNESDAY MORNING...THE AMOUNT OF MOISTURE NEEDED TO
SATURATE THE 310K SURFACE WAS ACTUALLY INCREASING. AS A RESULT...
DID NOT INCLUDE THE THE PRECIPITATION IN THE FORECAST FOR
WEDNESDAY MORNING.
ON WEDNESDAY...TEMPERATURES WILL CLIMB INTO THE LOWER AND MID 90S
ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND PARTS OF WESTERN
WISCONSIN. THESE TEMPERATURES WILL BE WARM ENOUGH THAT A FEW
RECORD HIGH TEMPERATURES MAY BE TIED OR BROKEN.
ON THURSDAY...THE 850 MB TEMPERATURES ARE RUNNING BETWEEN 2 AND
2.5 STANDARD DEVIATIONS ABOVE NORMAL IN THE GFS AND 2.5 TO 3
STANDARD DEVIATIONS ABOVE NORMAL IN THE ECMWF. IN ADDITION...THERE
WILL BE MODERATE SOUTHWEST GRADIENT AHEAD OF A WEAKENING COLD
FRONT. THIS WILL AID IN THE MIXING OF THE WARM AIR TO SURFACE.
HIGH TEMPERATURES NEAR 100 WILL BE POSSIBLE ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR AND IN THE MID AND UPPER 90S ACROSS THE
REMAINDER OF THE AREA. WITH RECORD HIGH TEMPERATURES IN THE MID
90S...THINKING THAT SEVERAL RECORDS COULD BE EASILY BROKEN.
.LONG TERM...THURSDAY NIGHT THROUGH LABOR DAY
345 AM CDT TUE AUG 28 2012
THE 28.00Z MODELS CONTINUE TO STRUGGLE ON WHERE THE REMNANTS OF
ISAAC WILL ULTIMATELY END UP. THEY ARE NOW TRYING TO BRING SOME OF
THIS MOISTURE IN OUR FAR SOUTHERN AREAS ON SATURDAY AND SATURDAY
NIGHT. ITS TRACK ON LAND LOOKS A BIT SIMILAR TO AN UNNAMED TROPICAL
STORM IN 1955...HURRICANE ELENA /1985/...AND HURRICANE GUSTAV
/2008/. IN ALL THREE OF THESE SYSTEMS...THE PRECIPITATION STAYED
SOUTH OF THE FORECAST AREA.
FOR SUNDAY NIGHT INTO LABOR DAY...THE MODELS CONTINUE TO MOVE A
COLD FRONT THROUGH THE AREA. THE GFS CONTINUE TO GENERATE SOME
PRECIPITATION WITH ITS PASSAGE. MEANWHILE THE ECMWF NOW HAS THIS
FRONTAL PASSAGE DRY.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1107 PM CDT MON AUG 27 2012
ANOTHER MORNING OF VALLEY FOG IS EXPECTED AT KLSE...DUE TO A RIDGE
OF HIGH PRESSURE MOVING OVERHEAD...DRY AIR AND LIGHT WINDS
ALLOWING FOR GOOD RADIATIONAL COOLING...AND MOISTENING OF THE AIR
FROM VEGETATION AND THE MISSISSIPPI RIVER. STILL ANTICIPATING
VLIFR CONDITIONS TO DEVELOP BETWEEN 10 TO 14Z. SCATTERED
ALTOCUMULUS OVER KRST...WHICH WAS LOOKING TO BE A POSSIBLE PROBLEM
FOR THE VALLEY FOG AT KLSE...SHOULD NOT MOVE IN UNTIL 12Z.
THEREFORE...CONFIDENCE IS HIGH THAT VALLEY FOG CAN DEVELOP BEFORE
THE CLOUDS MOVE IN. OTHERWISE...ADDITIONAL ALTOSTRATUS IS EXPECTED
TO CROSS BOTH TAF SITES THROUGH 06Z WEDNESDAY. STILL...CEILINGS
AND VISIBILITIES WILL END UP VFR DUE TO PLENTY OF LOW LEVEL DRY
AIR. THERE IS A SLIGHT CHANCE OF A SHOWER/THUNDERSTORM AT KRST
BETWEEN 15-20Z...COMING OUT OF THE AFOREMENTIONED ALTOSTRATUS
DECK...BUT NOT ENOUGH CONFIDENCE EXISTS TO EVEN MENTION A VCSH IN
THE KRST TAF.
&&
.FIRE WEATHER...THURSDAY
345 AM CDT TUE AUG 28 2012
THE SOUTHWEST WINDS WILL CLIMB INTO THE 15 TO 20 KNOT RANGE AND
RELATIVE HUMIDITIES WILL FALL INTO THE 20 TO 30 PERCENT RANGE.
THIS WILL LIKELY DRY OUT THE FINE FUELS RAPIDLY ESPECIALLY IN THE
DROUGHT AREAS. AS A RESULT...CONCERNED THAT THIS COULD BE AN
ACTIVE FIRE WEATHER DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
345 AM CDT TUE AUG 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS ALBANY NY
647 AM EDT TUE AUG 28 2012
.SYNOPSIS...
SHOWERS AND ISOLATED THUNDERSTORMS WILL END FROM WEST TO EAST
THIS MORNING AS A COLD FRONT PASSES THROUGH THE AREA. THIS FRONT
WILL ALLOW FOR DRIER WEATHER WITH PLEASANTLY MILD AFTERNOONS AND
COOL NIGHTS FOR THE MID WEEK PERIOD. WARM TEMPERATURES AND MORE
HUMID CONDITIONS WILL RETURN FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 633 AM EDT...A SHORTWAVE TROUGH WAS SITUATED OVER THE
NORTHEAST WITH A SFC COLD FRONT MOVING EASTWARD TOWARDS OUR CWA
FROM WEST TO EAST. THE FRONT WAS CURRENTLY SOMEWHERE JUST EAST OF
THE I-81 CORRIDOR.
AHEAD OF THE COLD FRONT...SHOWERS AND THUNDERSTORMS ARE MOVING
ACROSS THE TACONICS AND INTO WESTERN NEW ENGLAND. SOME OF THE
SHOWERS AND STORMS HAVE STARTED TO ORGANIZE INTO A BIT OF A LINE
AS THEY QUICKLY ADVANCE EASTWARD. THIS IS SIMILAR TO WHAT SEVERAL
RUNS OF THE 3KM HRRR HAS BEEN SHOWING THIS MORNING. DESPITE THE
TIME OF DAY AND LACK OF INSTABILITY...THERE IS SOME ORGANIZATION TO
THESE SHOWERS/STORMS. THE RUC13 CONTINUES TO SHOW LOW VALUES OF
MLCAPE ACROSS MOST OF OUR AREA...ALTHOUGH IT CURRENTLY SHOWS THAT THE
TACONICS INTO WESTERN NEW ENGLAND CONTAIN 300-700 J/KG...WITH EVEN
HIGHER AMOUNTS ACROSS LONG ISLAND AND EASTERN NEW ENGLAND THROUGH
MID MORNING. AT THIS POINT...WE DON/T ANTICIPATE ANY SEVERE WEATHER
WITH THIS DEVELOPING LINE...BUT WITH 0-6 KM BULK SHEAR VALUES OF
AROUND 40 KTS AND DEWPOINTS AROUND 70 DEGREES F...WE WILL CONTINUE
TO MONITOR RADAR TRENDS AS THE SHOWERS MOVE TOWARDS THE
BERKSHIRES/LITCHFIELD HILLS. THE BIGGEST THREAT WILL BE HEAVY
RAINFALL THAT CAN CAUSE PONDING OF WATER IN URBAN OR POOR DRAINAGE
AREAS.
THE FRONT SHOULD PASS THROUGH THE ENTIRE AREA BY THE MID TO LATE
MORNING HOURS...ENDING ANY THREAT FOR SHOWERS OR ISOLD
THUNDERSTORMS. SKIES SHOULD CLEAR OUT AND BECOME MOSTLY SUNNY IN
VALLEY AREAS DURING THE AFTN. OUR FORECASTED MAX TEMPS ARE A
MET/MAV BLEND...WITH LOW TO MID 80S FOR VALLEY AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
DRY WEATHER IS EXPECTED ACROSS THE ENTIRE SHORT TERM PERIOD AS SFC
HIGH PRESSURE AREA MOVES FROM THE GREAT LAKES REGION TONIGHT
TOWARDS THE OHIO VALLEY FOR WEDNESDAY AND TOWARDS THE MID ATLANTIC
FOR THURSDAY INTO THURSDAY NIGHT. THIS WILL ALLOW FOR AN EXTENDED
PERIOD OF DRY CONDITIONS...WITH SUNNY TO MOSTLY SUNNY SKIES DURING
THE DAY AND CLEAR SKIES AT NIGHT. THIS SETUP WILL ALLOW FOR GOOD
RADIATIONAL COOLING AT NIGHT...AND VALLEY FOG TO DEVELOP IN THE
TYPICALLY FAVORED LOCATIONS PRIOR TO SUNRISE.
WITH THE PASSING UPPER TROUGH...TEMPS ALOFT WILL BE COOL FOR
WEDNESDAY...AND THIS WILL KEEP MAX TEMPS GENERALLY IN THE 70S AND
DEWPOINTS MAINLY IN THE 40S. MAX TEMPS SHOULD WARM UP SEVERAL
DEGREES BACK INTO THE LOW TO MIDDLE 80S FOR THURSDAY AS THE FLOW
SWITCHES AROUND TO THE SW AND ADVECTS WARMER AND SLIGHTLY MORE
HUMID AIR BACK INTO THE REGION. MIN TEMPS WILL BE CHILLY...WITH
WIDESPREAD 40S TO LOW 50S FOR BOTH TONIGHT AND WED NIGHT. A FEW
SPOTS IN THE CENTRAL ADIRONDACKS WILL EVEN DROP INTO THE 30S. MIN
TEMPS WON/T BE QUITE AS COOL FOR THURSDAY NIGHT...WITH MAINLY 50S
ACROSS THE AREA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AT THIS TIME...THERE ARE INDICATIONS THAT RIDGING MAY DOMINATE MUCH
OF THE PERIOD WITH DRY WEATHER. HOWEVER...THE EVENTUAL TRACK OF THE
REMNANTS OF ISAAC ARE UNCERTAIN AS WE HEAD THROUGH THE WEEKEND INTO
EARLY NEXT WEEK WITH A WIDE SPREAD IN MODEL SOLUTIONS. A WIDESPREAD
RAINFALL WOULD BE BENEFICIAL. PLEASE REFER TO PRODUCTS ISSUED BY THE
NATIONAL HURRICANE CENTER FOR THE OFFICIAL FORECAST TRACK FOR ISAAC
AS ITS MAKES LANDFALL AND HEADS INLAND. ALSO PLEASE REFER TO
QUANTITATIVE PRECIPITATION FORECASTS ISSUED BY THE
HYDROMETEOROLOGICAL PREDICTION CENTER FOR EXPECTED RAINFALL
ASSOCIATED WITH ISAAC AND ITS REMNANTS.
AS FOR TEMPERATURES...IT LOOKS LIKE WE WILL END AUGUST AND START
SEPTEMBER WITH ABOVE NORMAL READINGS BY AROUND 10 DEGREES. WITH A
WESTERLY FLOW EXPECTED TEMPERATURES IN THE VALLEYS MAY BE NEAR OR
JUST ABOVE 90 DEGREES ESPECIALLY IN THE MID HUDSON VALLEY. COOLER
MORE SEASONABLE TEMPERATURES ARE ANTICIPATED AS WE HEAD THROUGH THE
HOLIDAY WEEKEND.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT MOVING ACROSS AREA WILL MOVE OFF TO OUR EAST BY
AFTERNOON. HIGH PRESSURE WILL THEN BUILD IN BEHIND THE FRONT.
SHOWERS AND A FEW THUNDERSTOTMS WILL CONTINUE TO MOVE EASTWARD
ACROSS THE LOCAL AREA THIS MORNING. VARIABLE CONDITIONS HAVE BEEN
OCCURRING WITH CONVECTION THIS MORNING WITH MAINLY MVFR/IFR WITH
SHOWERS. CONDITIONS ARE EXPECTED TO IMPROVE TO VFR BY MID TO LATE
MORNING WITH SKIES EVENTUALLY BECOMING CLEAR THIS EVENING. WITH
CLEAR SKIES...WET/DAMP GROUND AND WINDS BECOMING LIGHT TO CALM
RADIATIONAL FOG IS EXPECTED TO DEVELOP. MVFR CONDITIONS ARE EXPECTED
WITH IFR CONDITIONS DEVELOPING AT KGFL AND KPSF.
LIGHT AND VARIABLE WINDS WILL BECOME WEST-NORTHWEST WITH THE FRONTAL
PASSAGE AND BECOME GUSTY THIS AFTERNOON ESPECIALLY AT KALB WITH
GUSTS OF 20 TO 25 KNOTS. WINDS WILL WEAKEN THIS EVENING AND BECOME
MORE NORTHERLY...THEN BECOMING LIGHT AND VARIABLE TO CALM
OVERNIGHT.
OUTLOOK...
TUE NIGHT-SAT...VFR.
&&
.FIRE WEATHER...
A WETTING RAINFALL OCCURRED EARLY THIS MORNING WITH SHOWERS ACROSS
THE ENTIRE AREA. SHOWERS WILL END FROM WEST TO EAST THIS MORNING
AS A COLD FRONT PASSES THROUGH THE AREA. THIS FRONT WILL ALLOW FOR
DRIER WEATHER WITH PLEASANTLY MILD AFTERNOONS AND COOL NIGHTS FOR
THE MID WEEK PERIOD. WARM TEMPERATURES AND MORE HUMID CONDITIONS
WILL RETURN FOR THE END OF THE WEEK.
RH VALUES OF NEAR 100 PERCENT EARLY THIS MORNING WILL DROP 40-50
PERCENT FOR THIS AFTERNOON. RH VALUES WILL RETURN TO NEAR 100
PERCENT WITH DEW AND FOG DEVELOPING. RH VALUES WILL BOTTOM OUT
AROUND 35 PERCENT ON WEDNESDAY AFTERNOON.
SOUTHERLY WINDS THIS MORNING WILL SWITCH TO A W-NW DIRECTION AT
10-15 MPH THIS AFTERNOON. THESE WINDS WILL DIMINISH TO NEARLY CALM
OVERNIGHT. N-NW WINDS AROUND 10 MPH ARE EXPECTED ON WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
SHOWERS WILL END THIS MORNING FROM WEST TO EAST ACROSS THE REGION
WITH THE PASSAGE OF A COLD FRONT. ALTHOUGH SOME SHOWERS EARLY THIS
MORNING MAY CONTAIN BRIEF BURSTS OF MODERATE RAINFALL...DRY
ANTECEDENT CONDITIONS WILL ALLOW FOR MUCH OF THIS RAINFALL TO BE
ABSORBED BY THE GROUND. ONLY SMALL RISES OF A FEW INCHES OR SO ARE
EXPECTED ON SMALL RIVERS AND STREAMS...WITH LARGER MAIN STEM
RIVERS HOLDING STEADY. HOWEVER...ANY AREAS THAT RECEIVE BURSTS OF
MODERATE RAINFALL MAY SEE PONDING OF WATER ON ROADWAYS OR IN AREAS
OF POOR DRAINAGE. THE THREAT FOR SHOWERS SHOULD END BY THE MID TO
LATE MORNING.
DRY WEATHER WILL RETURN THIS AFTERNOON AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER LEVELS TO HOLD STEADY
OR VERY SLOWLY FALL.
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...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
634 AM EDT TUE AUG 28 2012
.SYNOPSIS...
SHOWERS AND ISOLATED THUNDERSTORMS WILL END FROM WEST TO EAST
THIS MORNING AS A COLD FRONT PASSES THROUGH THE AREA. THIS FRONT
WILL ALLOW FOR DRIER WEATHER WITH PLEASANTLY MILD AFTERNOONS AND
COOL NIGHTS FOR THE MID WEEK PERIOD. WARM TEMPERATURES AND MORE
HUMID CONDITIONS WILL RETURN FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 633 AM EDT...A SHORTWAVE TROUGH WAS SITUATED OVER THE
NORTHEAST WITH A SFC COLD FRONT MOVING EASTWARD TOWARDS OUR CWA
FROM WEST TO EAST. THE FRONT WAS CURRENTLY SOMEWHERE JUST EAST OF
THE I-81 CORRIDOR.
AHEAD OF THE COLD FRONT...SHOWERS AND THUNDERSTORMS ARE MOVING
ACROSS THE TACONICS AND INTO WESTERN NEW ENGLAND. SOME OF THE
SHOWERS AND STORMS HAVE STARTED TO ORGANIZE INTO A BIT OF A LINE
AS THEY QUICKLY ADVANCE EASTWARD. THIS IS SIMILAR TO WHAT SEVERAL
RUNS OF THE 3KM HRRR HAS BEEN SHOWING THIS MORNING. DESPITE THE
TIME OF DAY AND LACK OF INSTABILITY...THERE IS SOME ORGANIZATION
TO THESE SHOWERS/STORMS. THE RUC13 CONTINUES TO SHOW LOW VALUES OF MLCAPE
ACROSS MOST OF OUR AREA...ALTHOUGH IT CURRENTLY SHOWS THAT THE
TACONICS INTO WESTERN NEW ENGLAND CONTAIN 300-700 J/KG...WITH EVEN
HIGHER AMOUNTS ACROSS LONG ISLAND AND EASTERN NEW ENGLAND THROUGH
MID MORNING. AT THIS POINT...WE DON/T ANTICIPATE ANY SEVERE
WEATHER WITH THIS DEVELOPING LINE...BUT WITH 0-6 KM BULK SHEAR
VALUES OF AROUND 40 KTS AND DEWPOINTS AROUND 70 DEGREES F...WE
WILL CONTINUE TO MONITOR RADAR TRENDS AS THE SHOWERS MOVE TOWARDS
THE BERKSHIRES/LITCHFIELD HILLS. THE BIGGEST THREAT WILL BE HEAVY
RAINFALL THAT CAN CAUSE PONDING OF WATER IN URBAN OR POOR DRAINAGE
AREAS.
THE FRONT SHOULD PASS THROUGH THE ENTIRE AREA BY THE MID TO LATE
MORNING HOURS...ENDING ANY THREAT FOR SHOWERS OR ISOLD
THUNDERSTORMS. SKIES SHOULD CLEAR OUT AND BECOME MOSTLY SUNNY IN
VALLEY AREAS DURING THE AFTN. OUR FORECASTED MAX TEMPS ARE A
MET/MAV BLEND...WITH LOW TO MID 80S FOR VALLEY AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
DRY WEATHER IS EXPECTED ACROSS THE ENTIRE SHORT TERM PERIOD AS SFC
HIGH PRESSURE AREA MOVES FROM THE GREAT LAKES REGION TONIGHT
TOWARDS THE OHIO VALLEY FOR WEDNESDAY AND TOWARDS THE MID ATLANTIC
FOR THURSDAY INTO THURSDAY NIGHT. THIS WILL ALLOW FOR AN EXTENDED
PERIOD OF DRY CONDITIONS...WITH SUNNY TO MOSTLY SUNNY SKIES DURING
THE DAY AND CLEAR SKIES AT NIGHT. THIS SETUP WILL ALLOW FOR GOOD
RADIATIONAL COOLING AT NIGHT...AND VALLEY FOG TO DEVELOP IN THE
TYPICALLY FAVORED LOCATIONS PRIOR TO SUNRISE.
WITH THE PASSING UPPER TROUGH...TEMPS ALOFT WILL BE COOL FOR
WEDNESDAY...AND THIS WILL KEEP MAX TEMPS GENERALLY IN THE 70S AND
DEWPOINTS MAINLY IN THE 40S. MAX TEMPS SHOULD WARM UP SEVERAL
DEGREES BACK INTO THE LOW TO MIDDLE 80S FOR THURSDAY AS THE FLOW
SWITCHES AROUND TO THE SW AND ADVECTS WARMER AND SLIGHTLY MORE
HUMID AIR BACK INTO THE REGION. MIN TEMPS WILL BE CHILLY...WITH
WIDESPREAD 40S TO LOW 50S FOR BOTH TONIGHT AND WED NIGHT. A FEW
SPOTS IN THE CENTRAL ADIRONDACKS WILL EVEN DROP INTO THE 30S. MIN
TEMPS WON/T BE QUITE AS COOL FOR THURSDAY NIGHT...WITH MAINLY 50S
ACROSS THE AREA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AT THIS TIME...THERE ARE INDICATIONS THAT RIDGING MAY DOMINATE MUCH
OF THE PERIOD WITH DRY WEATHER. HOWEVER...THE EVENTUAL TRACK OF THE
REMNANTS OF ISAAC ARE UNCERTAIN AS WE HEAD THROUGH THE WEEKEND INTO
EARLY NEXT WEEK WITH A WIDE SPREAD IN MODEL SOLUTIONS. A WIDESPREAD
RAINFALL WOULD BE BENEFICIAL. PLEASE REFER TO PRODUCTS ISSUED BY THE
NATIONAL HURRICANE CENTER FOR THE OFFICIAL FORECAST TRACK FOR ISAAC
AS ITS MAKES LANDFALL AND HEADS INLAND. ALSO PLEASE REFER TO
QUANTITATIVE PRECIPITATION FORECASTS ISSUED BY THE
HYDROMETEOROLOGICAL PREDICTION CENTER FOR EXPECTED RAINFALL
ASSOCIATED WITH ISAAC AND ITS REMNANTS.
AS FOR TEMPERATURES...IT LOOKS LIKE WE WILL END AUGUST AND START
SEPTEMBER WITH ABOVE NORMAL READINGS BY AROUND 10 DEGREES. WITH A
WESTERLY FLOW EXPECTED TEMPERATURES IN THE VALLEYS MAY BE NEAR OR
JUST ABOVE 90 DEGREES ESPECIALLY IN THE MID HUDSON VALLEY. COOLER
MORE SEASONABLE TEMPERATURES ARE ANTICIPATED AS WE HEAD THROUGH THE
HOLIDAY WEEKEND.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT WILL ACROSS THE REGION THIS MORNING WITH SHOWERS AND
POSSIBLY A THUNDERSTORM. HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT.
SHOWERS WILL CONTINUE TO MOVE EASTWARD ACROSS THE LOCAL AREA THIS
MORNING IMPACTING THE TAF SITES. VARIABLE CONDITIONS WITH MVFR
EXPECTED WITH THE SHOWERS WITH IFR POSSIBLE. MODEL GUIDANCE IS IN
GOOD AGREEMENT THAT THE SHOWERS WILL END EARLY THIS MORNING ACROSS
THE LOCAL AREA AND CONDITIONS WILL IMPROVE.
LIGHT TO CALM WINDS WILL BECOME WEST-NORTHWEST WITH THE FRONTAL
PASSAGE AND BECOME GUSTY THIS AFTERNOON ESPECIALLY AT KALB WITH
GUSTS OF 20 TO 25 KNOTS. WINDS WILL WEAKEN THIS EVENING AND BECOME
MORE NORTHERLY.
OUTLOOK...
TUE NIGHT-SAT...VFR.
&&
.FIRE WEATHER...
A WETTING RAINFALL OCCURRED EARLY THIS MORNING WITH SHOWERS ACROSS
THE ENTIRE AREA. SHOWERS WILL END FROM WEST TO EAST THIS MORNING
AS A COLD FRONT PASSES THROUGH THE AREA. THIS FRONT WILL ALLOW FOR
DRIER WEATHER WITH PLEASANTLY MILD AFTERNOONS AND COOL NIGHTS FOR
THE MID WEEK PERIOD. WARM TEMPERATURES AND MORE HUMID CONDITIONS
WILL RETURN FOR THE END OF THE WEEK.
RH VALUES OF NEAR 100 PERCENT EARLY THIS MORNING WILL DROP 40-50
PERCENT FOR THIS AFTERNOON. RH VALUES WILL RETURN TO NEAR 100
PERCENT WITH DEW AND FOG DEVELOPING. RH VALUES WILL BOTTOM OUT
AROUND 35 PERCENT ON WEDNESDAY AFTERNOON.
SOUTHERLY WINDS THIS MORNING WILL SWITCH TO A W-NW DIRECTION AT
10-15 MPH THIS AFTERNOON. THESE WINDS WILL DIMINISH TO NEARLY CALM
OVERNIGHT. N-NW WINDS AROUND 10 MPH ARE EXPECTED ON WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH AT LEAST THE
NEXT FIVE DAYS.
SHOWERS WILL END THIS MORNING FROM WEST TO EAST ACROSS THE REGION
WITH THE PASSAGE OF A COLD FRONT. ALTHOUGH SOME SHOWERS EARLY THIS
MORNING MAY CONTAIN BRIEF BURSTS OF MODERATE RAINFALL...DRY
ANTECEDENT CONDITIONS WILL ALLOW FOR MUCH OF THIS RAINFALL TO BE
ABSORBED BY THE GROUND. ONLY SMALL RISES OF A FEW INCHES OR SO ARE
EXPECTED ON SMALL RIVERS AND STREAMS...WITH LARGER MAIN STEM
RIVERS HOLDING STEADY. HOWEVER...ANY AREAS THAT RECEIVE BURSTS OF
MODERATE RAINFALL MAY SEE PONDING OF WATER ON ROADWAYS OR IN AREAS
OF POOR DRAINAGE. THE THREAT FOR SHOWERS SHOULD END BY THE MID TO
LATE MORNING.
DRY WEATHER WILL RETURN THIS AFTERNOON AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER LEVELS TO HOLD STEADY
OR VERY SLOWLY FALL.
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...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MIAMI FL
1041 AM EDT TUE AUG 28 2012
.UPDATE...
THE BIG CONCERN FOR THIS AFTERNOON IS ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ACROSS PALM BEACH AND BROWARD COUNTY. A RAINBAND
REMAINS OFFSHORE OF CENTRAL FLORIDA OVER THE ATLANTIC WATERS THIS
MORNING. MODELS ARE INDICATING THAT THE MOISTURE GRADIENT WILL
SHIFT TO THE WEST OVER THE EAST COAST THIS AFTERNOON AS HIGH
PRESSURE BUILDS TO THE WEST. THE HRRR SHOWS THAT NUMEROUS TO
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THESE AREAS
ONCE AGAIN THIS AFTERNOON. SO BUMPED UP POPS TO 70-80 PERCENT
ACROSS PALM BEACH AND BROWARD COUNTIES...AND INCREASED QPF AMOUNTS
FOR THESE AREAS. ANY ADDITIONAL RAINFALL WILL EXACERBATE THE
FLOODING CONDITIONS IN THESE COUNTIES AS THERE IS STILL STANDING
WATER AND ONGOING FLOODING. SO THE FLOOD WATCH AND AREAL FLOOD
WARNING WILL CONTINUE THROUGH THIS EVENING FOR BROWARD AND PALM
BEACH COUNTY. KEPT POPS THE SAME FOR THE REST OF THE REGION...WITH
SCATTERED TO NUMEROUS SHOWERS AND STORMS POSSIBLE.
THE 12Z SOUNDING THIS MORNING SHOWED A PWAT OF ALMOST 2.4 INCHES.
A CONSERVATIVE TEMPERATURE OF 88 DEGREES AND DEWPOINT OF 76 SHOWS
OVER 4000 J/KG OF CAPE THIS AFTERNOON. SO BUMPED UP THE THREAT FOR
SEVERE STORMS THIS AFTERNOON...WITH THE MAIN THREAT BEING
DOWNBURSTS DUE TO WATER LOADING. MADE SOME MINOR ADJUSTMENTS TO
TEMPERATURES AND CLOUD COVER ACROSS THE REGION TODAY.
&&
.PREV DISCUSSION... /ISSUED 406 AM EDT TUE AUG 28 2012/
..ANOTHER WET DAY TODAY BEFORE DRIER WEATHER RETURNS TO SOUTH FLORIDA...
SHORT TERM...
TROPICAL STORM ISAAC IS STILL FORECAST BY THE NATIONAL HURRICANE
CENTER TO MOVE NORTHWEST TOWARDS LOUISIANA COAST TODAY. AT THE SAME
TIME...HIGH PRESSURE WILL BE SLOWLY BUILDING INTO THE AREA FROM
THE WESTERN ATLANTIC WATERS TODAY. THIS WILL ALLOW FOR THE
STEERING FLOW TO REMAIN SOUTHERLY OVER THE CWA KEEPING THE DEEP
TROPICAL MOISTURE IN PLACE. THE LATEST HIGH RESOLUTION RAPID
REFRESH PRECIP MODEL (HRRR) IS ALSO SHOWING THAT THERE COULD BE A
FEW FAR FEEDER BANDS FROM ISAAC SETTING UP OVER THE FLORIDA
PENINSULA. SO WILL KEEP SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS OVER THE CWA TODAY ALONG WITH LOCALLY HEAVY
RAINFALL. THIS WILL ALSO LEAD TO MORE FLOOD PROBLEMS OVER PALM
BEACH AND BROWARD COUNTIES TODAY. MORE ON THIS IN THE HYDRO
SECTION BELOW.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA FROM THE
WESTERN ATLANTIC WATERS TONIGHT INTO THURSDAY ALLOWING FOR THE
STEERING FLOW TO BECOME EASTERLY BY LATE TONIGHT. THIS WILL ALSO
ALLOW FOR SOME DRIER AIR TO WORK INTO THE CWA FROM THE ATLANTIC
WATERS WITH THE PWAT VALUES DROPPING FROM 2.3 INCHES TODAY DOWN TO
1.8 INCHES FOR WEDNESDAY INTO THURSDAY (WHICH IS NEAR NORMAL FOR
THIS TIME OF YEAR). SO WILL KEEP THE SCATTERED POPS OVER THE CWA
FOR WEDNESDAY AND THURSDAY WITH THE HIGHEST POPS OVER THE INTERIOR
AND WEST COAST AREAS.
LONG TERM...
THE HIGH WILL REMAIN OVER THE WESTERN ATLANTIC WATERS WHILE
EXTENDING INTO THE FLORIDA PENINSULA THIS WEEKEND KEEPING THE
EASTERLY STEERING FLOW IN PLACE. SO WILL CONTINUE TO SHOW THE
TYPICAL SUMMER TIME WEATHER PATTERN OVER SOUTH FLORIDA WITH MAINLY
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EACH
DAY.
MARINE...
THE WIND DIRECTION TODAY WILL BE SOUTHERLY TODAY BEFORE SWINGING
TO A SOUTHEAST DIRECTION TONIGHT...THEN AN EASTERLY DIRECTION BY
WEDNESDAY. THE WIND SPEEDS OVER MOST OF THE LOCAL WATERS TODAY
WILL BE 15 TO 20 KNOTS BEFORE DECREASING TO 15 KNOTS OR LESS BY
TONIGHT. THE ONLY EXCEPTION TO THIS IS FOR THE GULF WATERS OF
SOUTH FLORIDA...WHERE THE SPEEDS WILL REMAIN ABOVE 20 KNOTS TODAY
BEFORE DECREASING TO 15 TO 20 KNOTS TONIGHT.
THIS WILL ALLOW FOR THE SEAS IN THE ATLANTIC WATERS TO FALL FROM 4
TO 6 FEET THIS MORNING DOWN TO 1 TO 3 FEET BY THIS EVENING. THE
NEAR-SHORE SEAS IN THE GULF WATERS WILL REMAIN BE 4 TO 6 FEET
THIS MORNING FALLING TO 1 TO 3 FEET BY THIS EVENING...WHILE THE
OFFSHORE SEAS WILL BE 7 TO 9 FEET THIS MORNING FALLING TO 5 TO 7
FEET BY THIS EVENING. THEREFORE...THE SCA WILL REMAIN UP FOR THE
GULF WATERS TODAY WHILE REST OF THE LOCAL WATERS WILL BE DROP AND
REPLACE BY SCEC FOR TODAY.
FIRE WEATHER...
THE RELATIVE HUMIDITIES WILL REMAIN WELL ABOVE THE 35 PERCENT
CRITICAL VALUE FOR THIS WEEK OVER SOUTH FLORIDA. SO NO PROBLEMS
ARE EXPECTED WITH THE FIRE WEATHER FOR SOUTH FLORIDA THIS WEEK.
HYDROLOGY...
TOTAL RAINFALL AMOUNTS OF 8 TO 13 INCHES HAVE BEEN REPORTED OVER
PALM BEACH COUNTY SINCE EARLY SUNDAY MORNING WITH DOPPLER RADAR
SHOWING BETWEEN 10 TO 20 INCHES FROM THE RAIN BANDS OF ISAAC. IN
BROWARD COUNTY...TOTAL RAINFALL AMOUNTS OF 8 TO 10 INCHES HAVE
BEEN REPORTED WITH DOPPLER RADAR SHOWING BETWEEN 8 TO 15 INCHES.
THESE RAINFALL AMOUNTS HAVE LEAD TO MAJOR FLOODING PROBLEMS IN
PORTIONS OF METRO PALM BEACH AND METRO BROWARD COUNTIES. OVER THE REST
OF SOUTH FLORIDA...TOTAL RAINFALL AMOUNTS OF 2 TO 5 INCHES HAVE
BEEN REPORTED WITH DOPPLER RADAR SHOWING BETWEEN 2 TO 8 INCHES.
WITH POSSIBLE ADDITIONAL HEAVY RAINFALL TODAY OVER SOUTH FLORIDA
AND MAJOR FLOODING PROBLEMS ON GOING OVER PORTIONS OF METRO PALM
BEACH AND METRO BROWARD COUNTIES...THE FLOOD WATCH WILL BE
EXTENDED UNTIL 8 PM THIS EVENING FOR PALM BEACH AND BROWARD
COUNTIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 78 90 78 / 80 40 40 20
FORT LAUDERDALE 90 80 90 80 / 70 30 30 20
MIAMI 90 79 91 79 / 50 20 40 20
NAPLES 89 77 90 77 / 50 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR COASTAL BROWARD-
COASTAL PALM BEACH-INLAND BROWARD-INLAND PALM BEACH-METRO
BROWARD-METRO PALM BEACH.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR COASTAL
BROWARD-COASTAL COLLIER-COASTAL MIAMI DADE-COASTAL PALM
BEACH.
AM...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION...UPDATED
NWS COLUMBIA SC
621 AM EDT TUE AUG 28 2012
.SYNOPSIS...
TROPICAL MOISTURE WILL CONTINUE TO STREAM NORTHWARD ACROSS THE
REGION TODAY AND TONIGHT. A COLD FRONT WILL DROP SOUTHWARD
WEDNESDAY AND INTERACT WITH THE MOISTURE. THE FRONTAL BOUNDARY
WILL CONTINUE INTO THURSDAY BEFORE WEAKENING FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THIS MORNING...SHOWERS CONTINUE TO MOVE NORTHWARD INTO THE REGION.
RUC13 MODELS IS SHOWING STRONG MOISTURE CONVERGENCE WITH BAND AS
IT MOVES NORTHWARD. RUC13 ALSO BRINGS A SHORT WAVE WITH THIS
CONVECTIVE ACTIVITY. LOCAL WRF MODEL SHOWS GOOD COVERAGE OF
PRECIPITATION BY 6 AM. INCREASED POPS FROM CHANCE TO LIKELY
TO CATEGORICAL BY LATE MORNING.
THIS AFTERNOON...MODELS SHOW UPPER TROUGH IN THE EAST DEEPENING.
THE SHORT WAVE MOVING NORTH REMAINS ACROSS THE REGION. DEEP
TROPICAL MOISTURE IS AVAILABLE WITH PW VALUES 2.3-2.4 INCHES.
EXPECT LOW LEVEL MOISTURE CONVERGENCE TO PRODUCE CATEGORICAL
POPS NEAR 100 PERCENT MOST OF THE AFTERNOON. INGREDIENTS ARE
THERE FOR POTENTIAL OF HEAVY RAIN. INCLUDED MENTION OF HEAVY RAIN
IN WEATHER GRIDS THROUGH MUCH OF THE AFTERNOON. DECIDED TO LOWER
HIGH TEMPERATURES TO THE LOWER 80S BELOW GUIDANCE BECAUSE OF HIGH
POPS AND CLOUD COVER. ALSO WITH MENTION THUNDERSTORMS THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
THE BERMUDA RIDGE CENTERED TO THE EAST WILL ALLOW FOR A LOW LEVEL
SOUTHEAST WIND FLOW TO ADVECT MORE MOISTURE TO THE REGION AND
INCREASE THE CHANCES FOR SHOWERS AND THUNDERSTORMS TONIGHT. IN
ADDITION...MODELS ARE IN GOOD AGREEMENT THAT A COLD FRONT WILL
APPROACH FROM THE NORTHWEST BY WEDNESDAY...THEN DRIFT SLOWLY SOUTH
OR STALL ACROSS THE REGION THROUGH THURSDAY. WILL KEEP FAIRLY HIGH
POPS 60-70 PERCENT TONIGHT AND WEDNESDAY. PW VALUES REMAIN HIGH AT
2.3 INCHES TONIGHT AND WEDNESDAY. ALSO VALUES WILL EXCEED 2 INCHES
THURSDAY. REASONABLE DYNAMICS WILL ALSO BE PRESENT IN THE FORM OF
THE RIGHT ENTRANCE REGION OF AN UPPER JET. THERE APPEARS TO BE
LITTLE CHANCE OF SEVERE WEATHER THROUGH THE PERIOD...HOWEVER HEAVY
RAIN WILL BE A SIGNIFICANT THREAT. HPC FIVE DAY QPF GIVES 2-4
INCHES OVER THE AREA. GUIDANCE AND LOCAL NUMBERS VERY CLOSE WITH
POPS AND TEMPERATURES THROUGH THE PERIOD. WILL STAY NEAR CONSENSUS
FOR TEMPERATURES AT AT/JUST ABOVE CONSENSUS FOR POPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNCERTAINTY REMAINS IN THE EXTENDED FORECAST AND HIGHLY DEPENDENT
ON THE EVENTUAL TRACK OF ISAAC. WILL CONTINUE WITH A MENTION OF
SHOWERS THROUGH THE EXTENDED AS MOISTURE REMAINS HIGH ACROSS THE
AREA AND THERE IS UNCERTAINTY AS TO THE MOVEMENT OF THE FRONTAL
BOUNDARY. TEMPERATURES WILL WARM BACK UP INTO THE UPPER 80S TO
NEAR 90 BY THE WEEKEND AS AN UPPER RIDGE BUILDS OVER THE AREA.
OVERNIGHT LOWS WILL BE IN THE LOWER 70S. THESE TEMPERATURES ARE
VERY CLOSE TO CLIMO FOR LATE AUGUST.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
WEAK SURFACE RIDGE OF HIGH PRESSURE JUST TO OUR NORTH...WITH TS
ISAAC WELL TO OUR SW OVER THE CENTRAL GULF OF MEXICO. LIGHT WINDS AT
THE SURFACE...WITH SOUTHERLY WINDS ABOVE THAT BRINGING IN A FETCH OF
MOISTURE AND SHALLOW ISENTROPIC LIFT LEADING TO SOME LOW CLOUDINESS
AND FOG. CONDITIONS HAVE BEEN QUITE VARIABLE EARLY THIS MORNING...WITH
RAPID FLUCTUATIONS BETWEEN VFR AND LIFR AT TIMES AT MANY SITES. WILL
CONCENTRATE ON NEAR TERM...INDICATING PERSISTENCE THROUGH ABOUT 13Z
OR SO USING TEMPO GROUPS TO INDICATE VARIABILITY...THEN WILL EXPECT
GRADUAL IMPROVEMENT IN CIGS WITH HEATING DURING THE MORNING. RADAR
INDICATES SOME LIGHT SHOWER ACTIVITY TO AFFECT PORTIONS OF THE
REGION EARLY THIS MORNING. WILL EXPECT SHOWER...AND POSSIBLE
THUNDERSTORM...COVERAGE TO INCREASE WITH HEATING DURING THE DAY. FOR
NOW...WILL HANDLE PRECIP CHANCES WITH VCSH THEN A PREDOMINATE SHRA
MENTION AFTER 17Z. FURTHER DETAIL CAN BE REFINED ONCE CONFIDENCE
WARRANTS.
NOTE...VSBY MISSING FROM OBS AT OGB.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS. GOOD
CHANCE OF SHOWERS AND A FEW THUNDERSTORMS WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 AM EDT TUE AUG 28 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 502 AM EDT TUE AUG 28 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE SRN/CNTRL ROCKIES INTO THE CNTRL PLAINS AND A TROUGH OVER NE
CANADA RESULTING IN NW FLOW THROUGH THE UPPER GREAT LAKES. AT THE
SFC...HIGH PRES EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR
INTO NRN WI. IR LOOP SHOWED THAT NRLY FLOW HAS BROUGHT SOME PATCHY
CLOUDS INTO UPPER MI WHILE MORE EXTENSIVE CLOUDS REMAINED NORTH OF
LAKE SUPERIOR.
TODAY...MODELS SUGGEST THAT ENOUGH MOISTURE WILL LINGER OVER THE
AREA SO THAT DAYTIME HEATING/MIXING WILL SUPPORT SCT-BKN CU BENEATH
A STRENGTHENING INVERSION AROUND 800 MB. 850 MB TEMPS IN THE 10C TO
12C RANGE WILL SUPPORT MAX READINGS IN THE MID TO UPPER 70S INLAND.
A WEAK GRADIENT WILL ALLOW LAKE BREEZES TO DEVELOP DURING THE
AFTERNOON KEEPING TEMPS CLOSER TO 70 ALONG LAKE SUPERIOR.
TONIGHT...WITH HIGH PRES BUILDING INTO ERN UPPER MI AND LOWER
MI...WEAK SRLY FLOW WILL DEVELOP. HOWEVER...WINDS SHOULD REMAIN
DECOUPLED AND ALLOW DECENT RADIATIONAL COOLING WITH INLAND MIN TEMPS
DROPPING TO AROUND 50.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 502 AM EDT TUE AUG 28 2012
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS AN UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AND HEIGHT RISES
AHEAD OF THIS SYSTEM...850MB TEMPS INCREASE TO AROUND 20C W AND 16C
E BY 00Z THU AS A IMPRESSIVE EML MOVES INTO THE AREA. 850MB TEMPS
START THE DAY A GOOD 5-6C COOLER...SO WE SHOULD NOT BE ABLE TO
ACHIEVE THE FULL POTENTIAL OF THE 20-16C 850MB TEMPS...ESPECIALLY
SINCE WE MAY NOT MIX AS HIGH AS THE WARMEST TEMPERATURES ALOFT.
HIGHS WED SHOULD BE IN THE MID 80S TO AROUND 90 WEST HALF...AND IN
THE MID 70S TO MID 80S EAST HALF. WARMEST TEMPS FAR WEST AND COOLEST
DOWN WIND OF LAKE MICHIGAN WITH A SSW WIND. LOW LEVEL MOISTURE
CONTINUES TO VARY BETWEEN MODELS...WITH THE 00Z/28 GFS BEING ON THE
HIGH SIDE /1000-700MB RH STILL UNDER 60 PERCENT/ AND THE 00Z/28 NAM
ON THE LOW SIDE /LESS THAN 45 PERCENT 1000-700MB RH/. USING A MORE
MODERATED BLEND OF THE TWO ALONG WITH OTHER MIDDLE OF THE ROAD
GUIDANCE...CONDITIONS WILL LEAD TO MIN SFC RH VALUES OF 30 TO 45
PERCENT. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH GUSTS OF
15-20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE PEAK OF THE EML
MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. MODEL
GUIDANCE VARIES WITH 850MB TEMPS BETWEEN 22C-26C. HIGH TEMPS IN THE
80S TO MID 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN/. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC TROUGH
MOVES TO JUST W OF THE CWA BY 00Z FRI. SW SFC WINDS WILL BE AROUND
15KTS WITH GUSTS AS HIGH AS 30-35KTS POSSIBLE. TEMPERATURES AND MORE
SO WINDS WILL BE HIGHLY DEPENDENT ON HOW HIGH WE CAN MIX. MOST
MODELS SHOW US MIXING TO AROUND 850MB...WHERE THEY HAVE WINDS OF
AROUND 35KTS. MODELS ALSO AGREE IN SHOWING ERN UPPER MI SEEING
INCREASED 850MB WINDS...SO IT MAY VERY WELL BE GUSTIER THERE. GALE
POTENTIAL WILL NEED TO BE MONITORED OVER LAKE MI NEARSHORE
ZONES...BUT GIVEN STRONG WAA IT APPEARS LESS LIKELY. VERY DRY
MID/LOW LEVELS WILL AGAIN LEAD TO MIN SFC RH GENERALLY IN THE 30-40
PERCENT RANGE /EXCEPT HIGHER IN THE 40-50 PERCENT RANGE DOWNWIND OF
LAKE MICHIGAN/...SO FIRE WEATHER CONCERNS WILL BE MORE ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI STILL LOOK ABOVE NORMAL AS
MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL WINDS.
TEMPS SAT LOOK A FEW OF DEGREES COOLER THAN FRI. MODELS THEN SHOW A
STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY THROUGH
MON...BUT WITH MODELS INHERENT INABILITY TO FORECAST TROPICAL
SYSTEMS...CONFIDENCE DECREASES SHARPLY AS THE REMNANTS OF ISAAC ARE
FORECAST TO BE S OF OR ENCROACHING UPON THE CWA LATE SAT THROUGH
SUN. THE FORECAST FOR SUN AND MON WILL BE HIGHLY DEPENDENT ON WHERE
MOISTURE FROM ISAAC ENDS UP...SO WILL NOT HAVE TOO HIGH OF POPS AND
WILL GO WITH CONSENSUS OF MODELS AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 737 AM EDT TUE AUG 28 2012
SHALLOW FOG AT KSAW IS EXPECTED TO BURN OFF SHORTLY AFTER 12Z.
OTHERWISE...HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE
REGION...RESULTING IN VFR CONDITIONS THROUGH THE FORECAST ALONG WITH
LIGHT WINDS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT TUE AUG 28 2012
QUIET CONDITIONS OVER THE MARINE AREAS THROUGH WEDNESDAY AS HIGH
PRESSURE BUILDS OVER THE GREAT LAKES REGION WITH LIGHT WINDS
EXPECTED. SOUTHWESTERLY WINDS WILL STRENGTHEN BY WEDNESDAY NIGHT AND
THURSDAY AHEAD OF A LOW PRESSURE SYSTEM OVER ONTARIO. HOWEVER...WITH
INCREASING STABILITY IN THE WAA REGIME WINDS ARE EXPECTED TO REMAIN
IN THE 15 TO 25 KT RANGE OVER THE SE HALF OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...
MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EDT TUE AUG 28 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH NC FROM THE NORTHWEST THIS
AFTERNOON AND WILL MOVE INTO THE AREA THIS EVENING AND OVERNIGHT.
THE COLD FRONT WILL WORK ITS WAY SLOWLY SOUTH THROUGH THE AREA ON
WEDNESDAY...BEFORE BECOMING STATIONARY NEAR THE SOUTH CAROLINA
STATE LINE THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM TUESDAY...
PRECIP IS EXPENDING ACROSS SC AND SOUTHEASTERN NC ALONG THE LEADING
EDGE OF A PLUME OF TROPICAL MOISTURE ASSOCIATED WITH TS ISAAC THIS
MORNING. 12Z RAOBS FROM KFFC...KCHS...AND KMHX ALL REPORT PW NOW IN
EXCESS OF 2 INCHES...UP TO 2.5 INCHES AT KCHS. THE LATEST RAP
SHOWS A REMNANT DISTURBANCE FROM CONVECTION NEAR FLORIDA ON MONDAY
MOVING INTO THE NC COASTAL PLAIN...WHICH IS WHERE THE STRONGER
CONVECTIVE ELEMENTS ARE LOCATED THIS MORNING. MEANWHILE...A COLD
FRONT STRETCHES FROM THE MID ATLANTIC STATES BACK WEST TOWARD THE
MID MS RIVER VALLEY REGION...AND WILL BEGIN TO BEND SOUTH ACROSS THE
APPALACHIANS INTO VA TODAY...APPROACHING THE NC/SC BORDER BY 00Z
THIS EVENING. NEAR TERM GUIDANCE SUGGESTS THE WESTERLY FLOW
OBSERVED AHEAD OF THE COLD FRONT WILL KEEP THIS PRECIP MOSTLY
FOCUSED FROM THE SOUTHERN PIEDMONT TOWARD THE COASTAL PLAIN THROUGH
THE EARLY AFTERNOON. BASED ON RADAR TRENDS...WE WILL INCREASE POPS
TO 70-80 PERCENT FROM ROUGHLY LAURINBURG TO GOLDSBORO.
NORTH OF HWY 64 TOWARD THE NC/VA BORDER...LESS CLOUDS AND STRONGER
INSOLATION ...WILL LEAD TO STRONGER HEATING AND AN AXIS OF
PRE-FRONTAL INSTABILITY THIS AFTERNOON...WHERE MLCAPE SHOULD
1000-1500 J/KG BASED ON MODIFIED RAP SOUNDINGS. STRONGER STORMS MAY
DEVELOP OVER THE NORTHERN PIEDMONT/COASTAL PLAIN AND SOUTHERN
VIRGINIA ALONG AND EXPECTED DIFFERENTIAL HEATING BOUNDARY AND/OR IN
THE VICINITY OF THE APPROACHING FRONT. TIMING BASED ON THE HRRR
WOULD BE 20Z OR AFTER. WHILE DEEP LAYER SHEAR IS WEAK OVER THE CWA
AT THE MOMENT...SPC MESOANALYSIS SHOWS 25-30KT NEAR THE FRONT OVER
NORTHERN VA WHERE STRONGER MID LEVEL FLOW RESIDES. COMBINED WITH
STRENGTHENING DCAPE ASSOCIATED WITH THE AFOREMENTIONED MID LEVEL DRY
AIR...A CLUSTERS OF STRONG TO SEVERE STORMS MAY DEVELOP OVER
SOUTHERN VA AND MOVE SOUTH INTO THE CWA....ALTHOUGH A WEAKENING
TREND WOULD BE EXPECTED AS THEY MOVE SOUTH INTO A LESS FAVORABLE
ENVIRONMENT AFTER SUNSET.
ADJUSTMENTS TO TEMPS WILL BE RELATIVELY MINOR...MAINLY LOWERING
HIGHS ACROSS THE SOUTH TO THE LOWER 80S...WITH UPPER 80S TO AROUND
90 ACROSS THE NORTH. -SMITH
A POSITIVELY TILTED NORTHERN STREAM SHORTWAVE TROUGH EXTENDING FROM
SOUTHEAST CANADA INTO THE OHIO VALLEY WILL PROGRESS EAST THROUGH
THROUGH THE NORTHEAST AND NORTHERN MID-ATLANTIC REGION BY LATE
AFTERNOON. NWP MODEL GUIDANCE HAS SLOWED DOWN THE TIMING OF THE
ATTENDANT TRAILING SFC COLD FRONT INTO THE AREA...DELAYING ITS
ARRIVAL INTO THE NORTHERN/NORTHWEST PIEDMONT UNTIL AFTER 00Z THIS
EVENING. WHILE SATELLITE AND RADAR TRENDS INDICATE THAT THE MOISTURE
AND ASCENT IS RATHER PUNY ALONG THE SOUTHERN TAIL END OF THE
TRAILING SFC COLD FRONT CURRENTLY OVER PARTS OF KENTUCKY AND WESTERN
TN...THE FRONT WILL FIND A PLUME OF TROPICAL MARITIME AIRMASS (PWATS
2.0-2.25")IN PLACE ACROSS THE CAROLINAS....DISTRIBUTED POLEWARD INTO
THE REGION BY ISAAC`S EXPANSIVE WIND FIELD AND AN EMBEDDED
PERTURBATION OFF THE SC/GA COAST.
CURRENT THINKING IS THAT WE WILL SEE THE BEST CONVECTIVE COVERAGE
ACROSS THE SOUTHERN/SOUTHEASTERN PORTION OF THE FORECAST LATE THIS
MORNING AND INTO THE EARLY AFTERNOON...WITH AN OVERALL MINIMUM
ACROSS THE NORTHERN TIER UNTIL THE FRONT MOVES INTO THE AREA
AOA 00Z...WITH A GOOD CHANCE POPS EVERYWHERE OVERNIGHT AS THE
LOW-LEVEL CONVERGENCE ZONE AND RT ENTRANCE REGION JET DYNAMICS
INTERACT WITH THE TROPICAL AIRMASS.
SEVERE THREAT REMAINS LOWS GIVEN WEAK WINDS ALOFT AND MEAGER
INSTABILITY BETWEEN 500 TO 1000 J/KG. FLOODING CONTINUES TO BE THE
MAIN THREAT...ESPECIALLY ACROSS THE SOUTHEAST WITH IT POSSIBLE THAT
SOME AREAS COULD SEE 2 TO 4 INCHES POSSIBLE.
AS FAR AS TEMPERATURES...COULD SEE SOME OF THE WARMEST READINGS
ACROSS THE NORTH TODAY...DEPENDING ON CLOUD/SHOWER COVERAGE.
HIGHS IN THE MID TO UPPER 80S. OVERNIGHT LOWS IN THE MID TO UPPER
60S NORTH TO LOWER 70S SOUTH.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 315 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
OVERALL MODEL CONSENSUS IS THAT THE FRONT WILL SAG SLOWLY SOUTHWARD
THROUGHOUT THE DAY ON WEDNESDAY...INVOF THE NC/SC BORDER BY 18 TO
21Z AS RIDGING BUILDS IN FROM THE WEST/NORTHWEST. ITS QUITE POSSIBLE
THAT WE COULD CONTINUE TO SEE A HEAVY RAIN THREAT ACROSS THE FAR
SOUTHERN COUNTIES...BUT MODELS HAVE REALLY CUT BACK QPF ACROSS THE
AREA WITH DRY AIR BEGINNING TO SPREAD INTO THE AREA FROM THE
NORTH/NORTHWEST. NOT ENTIRELY SOLD ON THIS QUICKER DRIER TREND...BUT
WILL LOWER POPS ACROSS THE NORTH ON WEDNESDAY...WITH THE MAIN
ACTIVITY EXPECTED SOUTH OF US 64. IT LATEST MODEL TRENDS ARE TO BE
BELIEVED...WEDNESDAY NIGHT COULD BE MOSTLY DRY...BUT AGAIN PREFER TO
EASE INTO THE FASTER TIMING OF DRYING THINGS OUT.
SEVERE THREAT LOOKS TO BE NEARLY ZERO GIVEN WIDESPREAD CLOUD
COVER/MOIST ENVIRONMENT. TEMPERATURES RANGING FROM MID 80S NORTH TO
TO LOWER 80S SOUTH. LOWS IN THE MID 60S NORTH TO NEAR 70 SOUTH.
THURSDAY THROUGH FRIDAY NIGHT...MODELS ARE SLOWLY COMING INTO BETTER
AGREEMENT WITH RESPECT TO THE TRACK ON THE REMNANTS OF ISAAC...AT
LEAST THROUGH THE END OF THE WORK WEEK. IT APPEARS ISAAC WILL
PROGRESS VERY SLOWLY NORTHWARD ONCE IT MAKES LANDFALL NEAR
SOUTHEASTERN LA LATER TODAY...WITH IT PROGGED TO ONLY BE NEAR
NORTHERN LA BY LATE THURSDAY INTO EARLY FRIDAY. CLOSER TO HOME...A
WEAKENING FRONTAL SYSTEM IS PROGGED TO BE LOCATED NEAR THE SOUTHERN
PORTIONS OF THE FORECAST AREA TO START THURSDAY BEFORE MOVING EVEN
FURTHER SOUTH OF THE AREA BY FRIDAY AS HIGH PRESSURE BOTH AT THE
SURFACE AND ALOFT BUILD INTO THE REGION. MOISTURE CONTENT WILL STILL
BE RATHER HIGH ON THURSDAY...ESPECIALLY ACROSS THE SOUTH AND WEST
WHERE PWAT VALUES ARE PROGGED TO BE NEAR 2 INCHES. HOWEVER...
MOISTURE WILL BEGIN TO DECREASE LATE THURSDAY AS DRIER AIR MOVES IN
WITH THE BUILDING HIGH PRESSURE. WITH ALL OF THIS IN MIND...WILL SEE
A DOWNWARD TREND IN POPS FOR THIS TIME FRAME. FOR THURSDAY...THE
BEST CHANCE FOR PRECIP WILL BE ACROSS THE SOUTHWEST (MID CHANCE
POPS)...WITH ONLY MINIMAL POPS FURTHER TO THE NORTHEAST (WHERE IT
COULD VERY WELL STAY DRY). ON FRIDAY...WILL KEEP THE SAME POP
PATTERN (HIGHEST SOUTHWEST...LOWEST NORTHEAST) BUT WILL LOWER
OVERALL CHANCES TO NO MORE THAN SLIGHT CHANCE. WE WILL ALSO SEE A
WARMING TREND DURING THIS TIME FRAME AS HEIGHTS RISE ACROSS THE
REGION...WITH GENERALLY LOW/MID 80S ON THURSDAY AND MID/UPPER 80S BY
FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
THERE IS STILL QUITE OF BIT OF UNCERTAINTY FOR THE LONG TERM PERIOD
AS OUR WEATHER WILL ULTIMATELY DEPEND ON THE TRACK OF THE REMNANTS
OF ISAAC...WHICH THE MODELS ARE STILL HAVING TROUBLE WITH THIS FAR
OUT. OVERALL...MODELS TRACK THE REMNANTS OF ISAAC NORTH THROUGH THE
MS RIVER VALLEY...AROUND THE MID LEVEL RIDGE THAT WILL BE LOCATED
OVER THE MID ATLANTIC/SOUTHEAST US. MODELS BEGIN TO BREAK THIS RIDGE
DOWN ON SATURDAY AS A NORTHERN STREAM TROUGH MOVES ACROSS SOUTHERN
CANADA/NORTHERN NEW ENGLAND (HOWEVER THIS IS MUCH FASTER THAN
PREVIOUS RUNS). AS A RESULT...THE REMNANTS OF ISAAC BEGIN TO MOVE
EAST AND THEN MODELS SHOW THEM LINGERING ACROSS THE SOUTHEAST US
THROUGH EARLY NEXT WEEK. THIS WOULD RESULT IN INCREASING PRECIP
CHANCES FOR EARLY IN THE WEEKEND AND THEN PERSISTING THROUGH EARLY
NEXT WEEK. HOWEVER...DUE TO THE HIGH UNCERTAINTY...WILL GO NO HIGHER
THAN LOW END CHANCE UNTIL CONFIDENCE INCREASES. TEMPS WILL REMAIN
NEAR NORMAL THROUGH THE PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 735 AM TUESDAY...
SOUTHERLY LOW LEVEL MOIST FLOW WILL BRING THE THREAT OF MVFR TO IFR
FOG AND STRATUS THIS MORNING ACROSS THE FORECAST AREA. CIGS WILL
IMPROVE TO VFR BY LATE MORNING TUESDAY WITH VFR VSBYS EXPECTED.
STRENGTHENING LOW-LEVEL SOUTHERLY FLOW WILL BRING SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE AREA BY LATE MORNING AND INTO THE
AFTERNOON...ESPECIALLY NEAR ACROSS THE SOUTH AND SOUTHEASTERN
PORTIONS OF THE FORECAST. BY THE LATE AFTERNOON AND EVENING...
THERE WILL BE A CHANCE FOR SHOWERS AND POSSIBLY STORMS EVERYWHERE AS
A SLOW MOVING COLD FRONT MOVES INTO THE AREA FROM THE NORTHWEST.
MODEL SOUNDINGS SUGGEST WIDESPREAD IFR TO MVFR CEILINGS TONIGHT
THROUGH EARLY WEDNESDAY MORNING WITH SCATTERED SHOWERS AS THE FRONT
SAGS SLOWLY SOUTHWARD.
EXPECT A RETURN TO VFR CONDITIONS ON WEDNESDAY...BUT THERE
WILL CONTINUE TO BE A CHANCE FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN TERMINALS
(KFAY) AS THE COLD FRONT SETTLES NEAR THE SC/NC BORDER.
RAIN CHANCES ARE EXPECTED TO SHIFT SOUTH OF THE AREA BY THURSDAY
WITH DRIER AIR FILTERING INTO THE AREA FROM THE NORTH. OUTSIDE OF
SOME MORNING FOG/STRATUS EACH MORNING...EXPECT PREDOMINATELY VFR
CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/SMITH
SHORT TERM...CBL/KRR
LONG TERM...KRR
AVIATION...CBL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
645 AM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 459 AM CDT/
FIRE WEATHER CONCERNS AT THE FOREFRONT TODAY...THOUGH IN THE
IMMEDIATE TERM WATCHING SOME ELEVATED THUNDERSTORMS WORK THEIR WAY
INTO NORTHWEST PARTS OF THE CWA. GREATER COVERAGE/INTENSITY STORMS
EXPECTED TO REMAIN NORTH AND NORTHEAST OF OUR FORECAST AREA IN AREA
OF STRONG MID LEVEL THETA-E ADVECTION WHICH IS PROGGED TO EXTEND
FROM FAR NORTHEAST SD/FAR SOUTHEAST ND INTO CENTRAL/SOUTHEAST MN
THIS MORNING. THAT SAID...WEAKER EXTENSION OF THETA-E ADVECTION
AHEAD OF COMPACT MID LEVEL WAVE WILL MOVE ACROSS OUR FORECAST AREA
THIS MORNING AND WILL TRACK 20-30 PERCENT POPS EASTWARD THROUGH 18Z.
DO NOT EXPECT MUCH RAINFALL TO REACH THE GROUND WITH THESE STORMS AS
SUB CLOUD LAYER IS QUITE DRY. HOWEVER...LIGHTNING THREAT IS THERE
AND AS SUCH FEEL ISOLATED MENTION IS WARRANTED.
TEMPERATURES TRICKIEST PART OF THE NEXT FEW DAYS...AS MODELS STILL
WILDLY DIVERGENT IN THEIR LOW LEVEL TEMPERATURE/MOISTURE PROFILES.
HOWEVER WARMER/DRIER NAM...ALTHOUGH IT SEEMS OVERLY MIXED AND WAY
TOO WARM IN ITS 2 METER TEMPERATURE FORECAST...HAS BETTER SUPPORT
FROM ECMWF/GEM IN 850/925MB TEMPERATURES...AND THUS HEDGING TOWARD
WARMER SIDE OF FORECAST TEMPERATURE GUIDANCE SEEMS THE WAY TO GO IN
THIS PATTERN. WITH THIS...HAVE NUDGED TEMPERATURES UP A LITTLE MORE
FROM PREVIOUS FORECAST FOR WEDNESDAY/THURSDAY. FORTUNATELY HUMIDITY
LEVELS EXPECTED TO REMAIN IN CHECK...AS DEEP MIXING NEEDED TO
ACHIEVE THE HOT TEMPERATURES WILL ALSO MIX DOWN DRIER AIR. WHILE
THIS IS GOOD NEWS AS FAR AS LIMITING NEED FOR HEAT ADVISORIES...IT
DOES PRODUCE SIGNIFICANT FIRE WEATHER CONCERNS AS ALLUDED TO ABOVE.
THIS IS DISCUSSED IN MUCH GREATER DETAIL IN FIRE WEATHER SECTION
OF THIS PRODUCT. HOWEVER...IN SHORT...GUSTY SOUTH WINDS AND LOW
AFTERNOON HUMIDITY LEVELS HAVE PROMPTED ISSUANCE OF RED FLAG WARNING
FOR THE LOWER JAMES/BIG SIOUX VALLEYS AND EXTREME NORTHEAST NEBRASKA
THIS AFTERNOON. FIRE WEATHER WATCH ALSO ISSUED FOR THESE AREAS...
ALONG WITH THE LOWER BRULE AREA IN SOUTH CENTRAL SD...FOR WEDNESDAY
AFTERNOON/EARLY EVENING. ALTHOUGH NO HEADLINES HAVE YET BEEN ISSUED
FOR THURSDAY...EXPANSION OF VERY HIGH/EXTREME FIRE DANGER AND
POTENTIAL RED FLAG CONDITIONS IS EXPECTED AND WILL WATCH THIS PERIOD
CLOSELY FOR HEADLINES OVER THE NEXT 12-24 HOURS.
LONGER RANGE SEES REMNANTS OF ISAAC PROGGED TO LIFT NORTH THROUGH
THE NATIONS MIDSECTION FRIDAY/SATURDAY...THEN TURNING EASTWARD BUT
LINGERING OVER THE WESTERN OHIO VALLEY INTO SUNDAY/MONDAY. WILL NOT
SEE ANY RAIN IN THIS AREA FROM THE ISAAC REMNANTS. HOWEVER...WILL
HAVE AN EFFECT IN SLOWING ANY POTENTIAL SOUTHEASTWARD PUSH OF COOL
FRONT WHICH IS FORECAST TO MOVE INTO OUR AREA LATE IN THIS FORECAST
PERIOD. THIS WILL RESULT IN PERSISTENCE OF WELL ABOVE NORMAL
TEMPERATURES RIGHT THROUGH THE LABOR DAY HOLIDAY. FRIDAY/SATURDAY
SHOULD BE WARMEST DAYS OF THE LONGER RANGE...THOUGH SHOULD BE COOLER
THAN MIDWEEK AS THERMAL RIDGE BREAKS TOWN AS THE THURSDAY/THURSDAY
NIGHT FRONT WASHES OUT. THUS HAVE TEMPERED HIGHS INTO THE UPPER 80S
TO MID 90S...WITH COOLEST READINGS LIKELY TO BE IN SOUTHEAST CWA ON
SATURDAY AS FLOW BEGINS TO PULL A LITTLE COOLER AIR OUT OF ISAAC
REMNANTS AS THEY MOVE INTO MISSOURI/SOUTHEAST IOWA. WITH NEXT COOL
FRONT SET TO MOVE IN SUNDAY/MONDAY TIME FRAME...COULD SEE POTENTIAL
FOR SHOWERS/THUNDERSTORMS SOME DURING THIS PERIOD. HOWEVER...OPTED
TO KEEP THE PERIOD DRY FOR NOW UNTIL MODELS GET A BETTER HANDLE ON
REMNANTS OF ISAAC AND EFFECT OF THAT ON FRONTAL TIMING.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
THE ENTIRE FORECAST PERIOD THROUGH 12Z WEDNESDAY SHOULD BE
REPRESENTED WELL BY VFR CONDITIONS. ISOLATED HIGH BASED LIGHT
SHOWERS WITH PERHAPS A RUMBLE OF THUNDER WILL SLIDE THROUGH AREAS
NORTH OF INTERSTATE 90 EARLY THIS MORNING...BUT EVEN THE HEAVIEST
SHOWER OR STORM WOULD LIKELY REMAIN ABOVE VFR THRESHOLDS. THE
PROBABILITY OF THUNDER IS SUCH THAT WILL NOT MENTION IN TAF FOR KFSD
OR KHON...BUT THERE WILL BE ISOLATED STORMS AROUND THE AREA THROUGH
AT LEAST MID MORNING. AS WEAK FRONT ACROSS CENTRAL SOUTH DAKOTA
SAGS SOUTHWARD AND STALLS LATER TONIGHT NEAR KFSD...MAY FIND ENOUGH
WEAK CONVERGENCE TO POOL MOISTURE NEAR AND POST FRONTAL...FOR SOME
SPOTTY MVFR VISIBILITIES STARTING AROUND 09Z. /CHAPMAN
&&
.FIRE WEATHER...
SUBTLE LOW LEVEL BOUNDARY TRAILING SOUTHWESTWARD FROM THE MID LEVEL
WAVE WILL DRIFT TOWARD WESTERN EDGE OF THE CWA THIS AFTERNOON. THIS
WILL LIMIT FIRE DANGER FOR THE MIDDLE JAMES/LOWER BRULE AREAS TODAY.
HOWEVER...LOW RELATIVE HUMIDITY LEVELS WILL STILL CREATE HIGH TO
VERY HIGH DANGER IN THESE AREAS. GREATER CONCERN FOR TODAY IS FROM
THE LOWER JAMES/LOWER BIG SIOUX VALLEY AREAS INTO EXTREME NORTHEAST
NEBRASKA. THIS FAR ENOUGH REMOVED FROM THE BOUNDARY THAT SOUTHERLY
GUSTS IN EXCESS OF 25 MPH ARE LIKELY WITH MIXING THIS AFTERNOON. THE
DEEP MIXING EXPECTED TO BRING DOWN SOME OF THE DRIER AIR EVIDENT ON
THE 28/00Z LBF RAOB LAST EVENING. NAM AND TO SOME EXTENT HRRR SEEM
TO CAPTURE THIS IDEA BEST AND HAVE LEANED CLOSER TO THESE MODELS FOR
DROPPING DEW POINTS WITH AFTERNOON MIXING. THIS RESULTS IN MINIMUM
HUMIDITY LEVELS OF 20-25 PERCENT IN THE CONCERN AREA THIS AFTERNOON
AND HAVE ISSUED A RED FLAG WARNING FOR THESE TWO FIRE WEATHER ZONES
TODAY.
WEDNESDAY A LITTLE MORE UNCERTAIN...AS THAT WEAK BOUNDARY FORECAST
TO PUSH INTO THE SOUTHERN CWA TONIGHT BEFORE STALLING AND LIFTING
SLOWLY BACK TO THE NORTH ON WEDNESDAY. QUESTION WILL BE WHETHER IT
WILL SHIFTS NORTH EARLY ENOUGH TO ALLOW STRONGER SOUTH WINDS TO MIX
DOWN THROUGH THE MISSOURI RIVER VALLEY AREAS. RELATIVE HUMIDITY FROM
SOUTH CENTRAL SD...THROUGH THE MISSOURI VALLEY INTO THE SIOUX CITY
AREA CERTAINLY WORTHY OF HEIGHTENED FIRE WATCH...AS ALL MODELS
EXCEPT GFS INDICATE AFTERNOON DEW POINTS MIXING DOWN INTO THE 40S...
RESULTING IN MINIMUM HUMIDITY VALUES BELOW 20 PERCENT. GIVEN LOWER
CONFIDENCE IN WEDNESDAY AFTERNOON WIND FORECAST...NOT COMFORTABLE
WITH A DAY 2 RED FLAG WARNING JUST YET. HOWEVER HAVE ISSUED A FIRE
WEATHER WATCH FOR THE AREAS OF CONCERN.
DESPITE ALL OF THE ABOVE...THURSDAY PRESENTS GREATEST FIRE WEATHER
CONCERN AT THIS POINT. NORTHERN STREAM WAVE TOPPING THE BROAD UPPER
RIDGE WILL DRAG A COOL FRONT INTO THE NORTHWEST 1/3 OF THE CWA BY
THURSDAY AFTERNOON. DEEP SOUTHWEST FLOW WITHIN LOW LEVEL JET AHEAD
OF THIS BOUNDARY WILL ALLOW FOR WIDESPREAD 20-25 MPH SUSTAINED WINDS
WITH GUSTS OF 30-35 MPH LIKELY OVER MUCH OF THE CWA. THIS ALONG WITH
STRONG THERMAL RIDGE AHEAD OF BOUNDARY COULD RESULT IN NEAR RECORD
HIGHS AROUND 100 DEGREES...AND DEW POINTS MIXING INTO THE 40S...WILL
AGAIN PRODUCE MINIMUM HUMIDITY VALUES BELOW 20 PERCENT IN SOUTHWEST
TO NORTHEAST CORRIDOR THROUGH THE CENTER OF THE CWA...LAKE ANDES AND
YANKTON...THROUGH SIOUX FALLS...INTO SOUTHWEST MN. GIVEN THE MORE
IMMEDIATE FIRE DANGER THE NEXT COUPLE OF DAYS...HAVE HELD OFF
ISSUING ANY HEADLINE FOR THURSDAY JUST YET...BUT WILL CERTAINLY
HIGHLIGHT VERY HIGH TO EXTREME FIRE DANGER IN THE HAZARDOUS WEATHER
OUTLOOK AND DAY SHIFT WILL WANT TO COORDINATE POTENTIAL HEADLINES
WITH AFFECTED FIRE OFFICIALS FOR POSSIBLE ISSUANCE THIS AFTERNOON OR
WEDNESDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR NEZ249.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ249.
SD...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR SDZ258.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR SDZ255-258.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1043 AM CDT TUE AUG 28 2012
.SHORT TERM...THROUGH TONIGHT
1043 AM CDT TUE AUG 28 2012
UPPER LEVEL SHORTWAVE MOVING THROUGH MINNESOTA ALONG WITH TWO
DIFFERENT AREAS OF SHOWERS/STORMS. FIRST IS ASSOCIATED WITH
WEAKENING OVERNIGHT LLJ/ELEVATED INSTABILITY ACROSS SOUTHERN
MINNESOTA. LATEST RADAR AND SATELLITE TRENDS CONTINUE TO SHOW A
DECREASE. SLIGHT CHANCES MAINLY WEST OF THE MISSISSIPPI RIVER LOOK
ON TRACK.
OTHER FEATURE OF NOTE IS AN AREA OF FRONTOGENESIS THAT IS
MAXIMIZED IN THE 600-500 MB LAYER MOVING THROUGH EASTERN
MINNESOTA. ISENTROPIC LIFT ON THE 315K SURFACE INCREASES AS WELL
BY 21Z AND THE LATEST 28.12Z NAM AND RAP SHOW THIS SLIDING INTO
WESTERN WISCONSIN THIS AFTERNOON ALONG WITH MOST UNSTABLE CAPES IN
THE 500 TO 1000 J/KG RANGE. HOWEVER...THIS WILL HAVE TO CONTEND
WITH SOME DRIER LOW-LEVEL AIR AND A GENERAL WEAKENING TREND...BUT
STILL WARRANTS LOW-END CHANCES ALONG MAINLY ALONG AND NORTH OF
I-90 IN WISCONSIN. LATEST MESO-MODELS ARE ALSO ON TRACK WITH
THIS FEATURE...KEEPING PRECIPITATION EAST OF THE MISSISSIPI RIVER AS
WELL. GIVEN MORE CLOUDS AND CHANCE OF SHOWERS/STORMS ACROSS THESE
AREAS...LOWERED HIGHS A FEW DEGREES TO THE 80-83 DEGREE RANGE.
.LONG TERM...THURSDAY NIGHT THROUGH LABOR DAY
345 AM CDT TUE AUG 28 2012
THE 28.00Z MODELS CONTINUE TO STRUGGLE ON WHERE THE REMNANTS OF
ISAAC WILL ULTIMATELY END UP. THEY ARE NOW TRYING TO BRING SOME OF
THIS MOISTURE IN OUR FAR SOUTHERN AREAS ON SATURDAY AND SATURDAY
NIGHT. ITS TRACK ON LAND LOOKS A BIT SIMILAR TO AN UNNAMED TROPICAL
STORM IN 1955...HURRICANE ELENA /1985/...AND HURRICANE GUSTAV
/2008/. IN ALL THREE OF THESE SYSTEMS...THE PRECIPITATION STAYED
SOUTH OF THE FORECAST AREA.
FOR SUNDAY NIGHT INTO LABOR DAY...THE MODELS CONTINUE TO MOVE A
COLD FRONT THROUGH THE AREA. THE GFS CONTINUE TO GENERATE SOME
PRECIPITATION WITH ITS PASSAGE. MEANWHILE THE ECMWF NOW HAS THIS
FRONTAL PASSAGE DRY.
&&
.AVIATION...TODAY AND TONIGHT
604 AM CDT TUE AUG 28 2012
SMALL COMPLEX OF STORMS OVER NORTHEAST SOUTH DAKOTA IS MOVING
SOUTHEAST ALONG A WARM FRONT AND IN AN AXIS OF 1000 J/KG OF MU
CAPE. THIS ACTIVITY WAS GENERATED BY A SHORT WAVE TROUGH THAT THE
28.00Z NAM BRINGS TOWARD THE AREA THIS AFTERNOON AND EVENING. THE
28.06Z HRRR AND 28.00Z HI RES ARW BOTH INDICATE THIS ACTIVITY
SHOULD DISSIPATE BY MID MORNING AS IT MOVES OUT OF THE CAPE AXIS
AND AS THE MOISTURE TRANSPORT AXIS WEAKENS. DO NOT PLAN TO SHOW
ANY CONVECTIVE THREAT AT EITHER TAF SITE BUT WILL BRING IN A MID
LEVEL VFR CEILING FROM THE CLOUDS ASSOCIATED WITH THE COMPLEX. AS
THE SHORT WAVE TROUGH COMES IN TO THE AREA...THE NAM SUGGESTS IT
WILL BE WEAKENING AS THE PV ADVECTION IN THE 500-300 MB LAYER
DECREASES FROM 32 PVU/S AT 18Z OVER CENTRAL MINNESOTA TO 14 PVU/S
AT 00Z OVER NORTHERN ILLINOIS. THIS SHOULD STILL BE ENOUGH TO
PRODUCE SOME ISOLATED CONVECTION...BUT CONFIDENCE THAT ANYTHING
THAT DEVELOPS WOULD HIT EITHER TAF SITE IS TOO LOW TO INCLUDE.
BUFKIT SOUNDING SUGGEST THAT EVEN IN CONVECTION DOES FORM...THE
LOW LEVELS ARE EXTREMELY DRY AND CEILINGS WOULD REMAIN VFR AND 8K
FEET OR HIGHER. WILL KEEP THE MID LEVEL VFR CEILINGS THROUGH THE
NIGHT PER THE NAM BUFKIT SOUNDINGS WHICH WILL PRECLUDE ANY FOG
FROM FORMING TONIGHT.
&&
.FIRE WEATHER...THURSDAY
345 AM CDT TUE AUG 28 2012
THE SOUTHWEST WINDS WILL CLIMB INTO THE 15 TO 20 KNOT RANGE AND
RELATIVE HUMIDITIES WILL FALL INTO THE 20 TO 30 PERCENT RANGE.
THIS WILL LIKELY DRY OUT THE FINE FUELS RAPIDLY ESPECIALLY IN THE
DROUGHT AREAS. AS A RESULT...CONCERNED THAT THIS COULD BE AN
ACTIVE FIRE WEATHER DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
345 AM CDT TUE AUG 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM...BOYNE
AVIATION...04
FIRE WEATHER...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 AM CDT TUE AUG 28 2012
.SHORT TERM...TODAY THROUGH THURSDAY
345 AM CDT TUE AUG 28 2012
AT 3 AM...STILL HAVE NOT SEEN MUCH VALLEY FOG DEVELOPING ACROSS
THE FORECAST AREA. THERE IS A LITTLE HAZE HANGING OVER THE
CITY...BUT NO SIGNS OF A STRATUS DECK DEVELOPING YET. IN ADDITION
THERE IS STILL A SLIGHT BREEZE HERE AT THE OFFICE AND A 3 TO
4 DEGREE TEMPERATURE/DEW POINT SPREAD ALONG THE MISSISSIPPI RIVER.
THEY HAVE FALLEN TO LESS TO AROUND 1 DEGREE SPREAD IN WISCONSIN
RIVER AND JUST IN THE PAST HOUR BOSCOBEL HAS CAME IN WITH A 1 1/2
MILE VISIBILITY DUE TO FOG. WITH THE RAP BUFKIT SOUNDINGS CONTINUING
TO SHOW A 10 TO 15 KNOT WIND IN THE LOWEST 1 KM AND THE 925 MB VAD
WIND PROFILERS ALSO SHOWING 10 TO 15 KNOT WINDS...BEGINNING TO
WONDER WHETHER THE VALLEY FOG WILL DEVELOP. DUE TO THIS...REDUCED
THE WIDESPREAD VALLEY FOG TO JUST AREAS OF VALLEY FOG.
FURTHER TO THE NORTHWEST...A CLUSTER OF SHOWERS AND THUNDERSTORMS
WERE DEVELOPING ACROSS SOUTHEAST NORTH DAKOTA AND NORTH CENTRAL
SOUTH DAKOTA. THIS PRECIPITATION IS ASSOCIATED WITH 850 TO 600 MB
WARM AIR ADVECTION AHEAD OF A SHORT WAVE TROUGH. BOTH THE MESO
MODELS AND OPERATIONAL MODELS ARE IN AGREEMENT THAT THIS AREA WILL
GRADUALLY WEAKEN AS IT MOVES SOUTHEAST TOWARD THE AREA THIS
AFTERNOON. WHILE THE 0-6 KM SHEAR IS GREATER THAN 40 KNOTS...THE
BUFKIT SOUNDINGS SHOW THAT THE SHEAR THAT ANY ELEVATED THUNDERSTORMS
WOULD FEEL WILL BE GENERALLY LESS THAN 10 KNOTS. EVEN THE DCAPE IS
NOT THAT IMPRESSIVE WITH VALUES GENERALLY LESS 500 J/KG. AS A
RESULT...NOT TOO CONCERNED WITH ANY OF THESE THUNDERSTORMS
BECOMING SEVERE.
TONIGHT AND WEDNESDAY MORNING - THE MODELS CONTINUE TO SHOW THAT
YET ANOTHER SHORT WAVE TROUGH WILL BE ROUNDING THE UPPER LEVEL
RIDGE. WEAK TO MODERATE 850 MB TO 600 MB MOISTURE TRANSPORT AND
WARM AIR ADVECTION WILL LIKELY LEAD TO THE DEVELOPMENT OF ISOLATED
SHOWERS AND THUNDERSTORMS. WHILE THE MOISTURE TRANSPORT CONTINUES
INTO WEDNESDAY MORNING...THE AMOUNT OF MOISTURE NEEDED TO
SATURATE THE 310K SURFACE WAS ACTUALLY INCREASING. AS A RESULT...
DID NOT INCLUDE THE THE PRECIPITATION IN THE FORECAST FOR
WEDNESDAY MORNING.
ON WEDNESDAY...TEMPERATURES WILL CLIMB INTO THE LOWER AND MID 90S
ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND PARTS OF WESTERN
WISCONSIN. THESE TEMPERATURES WILL BE WARM ENOUGH THAT A FEW
RECORD HIGH TEMPERATURES MAY BE TIED OR BROKEN.
ON THURSDAY...THE 850 MB TEMPERATURES ARE RUNNING BETWEEN 2 AND
2.5 STANDARD DEVIATIONS ABOVE NORMAL IN THE GFS AND 2.5 TO 3
STANDARD DEVIATIONS ABOVE NORMAL IN THE ECMWF. IN ADDITION...THERE
WILL BE MODERATE SOUTHWEST GRADIENT AHEAD OF A WEAKENING COLD
FRONT. THIS WILL AID IN THE MIXING OF THE WARM AIR TO SURFACE.
HIGH TEMPERATURES NEAR 100 WILL BE POSSIBLE ALONG AND NORTH OF THE
INTERSTATE 90 CORRIDOR AND IN THE MID AND UPPER 90S ACROSS THE
REMAINDER OF THE AREA. WITH RECORD HIGH TEMPERATURES IN THE MID
90S...THINKING THAT SEVERAL RECORDS COULD BE EASILY BROKEN.
.LONG TERM...THURSDAY NIGHT THROUGH LABOR DAY
345 AM CDT TUE AUG 28 2012
THE 28.00Z MODELS CONTINUE TO STRUGGLE ON WHERE THE REMNANTS OF
ISAAC WILL ULTIMATELY END UP. THEY ARE NOW TRYING TO BRING SOME OF
THIS MOISTURE IN OUR FAR SOUTHERN AREAS ON SATURDAY AND SATURDAY
NIGHT. ITS TRACK ON LAND LOOKS A BIT SIMILAR TO AN UNNAMED TROPICAL
STORM IN 1955...HURRICANE ELENA /1985/...AND HURRICANE GUSTAV
/2008/. IN ALL THREE OF THESE SYSTEMS...THE PRECIPITATION STAYED
SOUTH OF THE FORECAST AREA.
FOR SUNDAY NIGHT INTO LABOR DAY...THE MODELS CONTINUE TO MOVE A
COLD FRONT THROUGH THE AREA. THE GFS CONTINUE TO GENERATE SOME
PRECIPITATION WITH ITS PASSAGE. MEANWHILE THE ECMWF NOW HAS THIS
FRONTAL PASSAGE DRY.
&&
.AVIATION...TODAY AND TONIGHT
604 AM CDT TUE AUG 28 2012
SMALL COMPLEX OF STORMS OVER NORTHEAST SOUTH DAKOTA IS MOVING
SOUTHEAST ALONG A WARM FRONT AND IN AN AXIS OF 1000 J/KG OF MU
CAPE. THIS ACTIVITY WAS GENERATED BY A SHORT WAVE TROUGH THAT THE
28.00Z NAM BRINGS TOWARD THE AREA THIS AFTERNOON AND EVENING. THE
28.06Z HRRR AND 28.00Z HI RES ARW BOTH INDICATE THIS ACTIVITY
SHOULD DISSIPATE BY MID MORNING AS IT MOVES OUT OF THE CAPE AXIS
AND AS THE MOISTURE TRANSPORT AXIS WEAKENS. DO NOT PLAN TO SHOW
ANY CONVECTIVE THREAT AT EITHER TAF SITE BUT WILL BRING IN A MID
LEVEL VFR CEILING FROM THE CLOUDS ASSOCIATED WITH THE COMPLEX. AS
THE SHORT WAVE TROUGH COMES IN TO THE AREA...THE NAM SUGGESTS IT
WILL BE WEAKENING AS THE PV ADVECTION IN THE 500-300 MB LAYER
DECREASES FROM 32 PVU/S AT 18Z OVER CENTRAL MINNESOTA TO 14 PVU/S
AT 00Z OVER NORTHERN ILLINOIS. THIS SHOULD STILL BE ENOUGH TO
PRODUCE SOME ISOLATED CONVECTION...BUT CONFIDENCE THAT ANYTHING
THAT DEVELOPS WOULD HIT EITHER TAF SITE IS TOO LOW TO INCLUDE.
BUFKIT SOUNDING SUGGEST THAT EVEN IN CONVECTION DOES FORM...THE
LOW LEVELS ARE EXTREMELY DRY AND CEILINGS WOULD REMAIN VFR AND 8K
FEET OR HIGHER. WILL KEEP THE MID LEVEL VFR CEILINGS THROUGH THE
NIGHT PER THE NAM BUFKIT SOUNDINGS WHICH WILL PRECLUDE ANY FOG
FROM FORMING TONIGHT.
&&
.FIRE WEATHER...THURSDAY
345 AM CDT TUE AUG 28 2012
THE SOUTHWEST WINDS WILL CLIMB INTO THE 15 TO 20 KNOT RANGE AND
RELATIVE HUMIDITIES WILL FALL INTO THE 20 TO 30 PERCENT RANGE.
THIS WILL LIKELY DRY OUT THE FINE FUELS RAPIDLY ESPECIALLY IN THE
DROUGHT AREAS. AS A RESULT...CONCERNED THAT THIS COULD BE AN
ACTIVE FIRE WEATHER DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
345 AM CDT TUE AUG 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
920 AM MST TUE AUG 28 2012
.SYNOPSIS...
STRONG HIGH PRESSURE SYSTEM WILL RESULT IN WARMER AFTERNOON
TEMPERATURES THROUGH FRIDAY. MONSOON MOISTURE WILL ALSO SHIFT WEST
INTO SOUTHEAST CALIFORNIA AND FAR SOUTHWEST ARIZONA FOR THE BEST
THREAT OF SHOWERS THROUGH THURSDAY. INCREASING MONSOON MOISTURE WITH
A CHANCE OF THUNDERSTORMS WILL SHIFT EAST AGAIN...AND INTO CENTRAL
ARIZONA FRIDAY AND THE WEEKEND. DRIER CONDITIONS WILL DEVELOP IN
SOUTHEAST CALIFORNIA THIS WEEKEND.
&&
.DISCUSSION...
EXTENDED NORTHERN WING OF VORTICITY/THETA-E ADVECTION ASSOCIATED
WITH AN INVERTED TROUGH PROGRESSING WEST THROUGH THE CNTRL BAJA
PENINSULA HAS SUPPORTED SHOWER DEVELOPMENT IN AN INCREASINGLY
SATURATED MIDLEVEL CLOUD FIELD THROUGH CNTRL/WRN IMPERIAL COUNTY.
RECENT HRRR FORECASTS HAVE ACCURATELY CAPTURED THIS
EVOLUTION...ALBEIT WITH SOME TEMPORAL DELAY...AND PUSH ANY RESIDUAL
SHOWER ACTIVITY WEST OF THE FORECAST AREA BY LATE MORNING.
OTHERWISE...MOST NOTABLE FEATURES ON WV IMAGERY ARE A WELL DEVELOPED
WAVE DIVING SOUTHWEST FAR OVER THE SIERRA OCCIDENTALS...WITH
ANTI-CYCLONIC SUBSIDENT CIRCULATION THROUGH ERN ARIZONA ADVECTING
DRY AIR WESTWARD FROM NEW MEXICO. REGIONAL 12Z SOUNDING DATA DOES
NOT OFFER MUCH HOPE FOR ORGANIZED CONVECTION SURVIVING OFF HIGHER
TERRAIN GENESIS REGIONS THIS AFTERNOON WITH WELL MIXED BOUNDARY
LAYER MOISTURE LESS THAN 10 G/KG UNDER A REGIME OF COMPRESSIONAL
HEATING THROUGH THE ATMOSPHERIC COLUMN...YIELDING LITTLE AVAILABLE
INSTABILITY. BOTH OPERATIONAL AND EXPERIMENTAL HIGH RESOLUTION
MODELS AGREE IN SUPPORTING THIS SCENARIO...WITH LITTLE TO NO QPF OR
SIMULATED RADAR ECHOES OVER THE FORECAST AREA THROUGH THE EVENING.
OVERALL...ONLY MINOR CHANGES WERE MADE TO FORECAST GRIDS IN THE
SHORT TERM WITH TRENDS CAPTURING THE CURRENT OBSERVATIONS WELL.
&&
.PREVIOUS DISCUSSION...
TODAY THROUGH THURSDAY...
INCREASING ATMOSPHERIC EASTERLY FLOW WILL SHIFT THE DEEPEST MONSOON
MOISTURE WEST...OUT OF AZ INTO SOUTHEAST CA AND THE COLORADO RIVER
VALLEY THROUGH THURSDAY. AT 2 AM...CONSIDERABLE CLOUDINESS WITH
ISOLATED SHOWERS WERE DETECTED NEAR THE YUMA AREA...MOVING WEST. THE
BEST AREA FOR SHWR AND TSTM THREATS THROUGH THURSDAY WILL EXIST OVER
SOUTHEAST CA AND NEAR THE COLORADO RIVER VALLEY.
FRIDAY AND THE WEEKEND...
A BIG CHANGE IN THE PATTERN WITH MORE WIDESPREAD THUNDERSTORM
ACTIVITY IS POSSIBLE IN CENTRAL ARIZONA THIS PERIOD. ATMOSPHERIC
WINDS FINALLY VEER FROM THE SOUTHWEST DIRECTION...AND...IT APPEARS
THAT A SIGNIFICANT MOISTURE SURGE FROM THE SOUTH IS POSSIBLE. ITS
HARD TO SAY...BUT SOME OF THIS MOISTURE MAY BE LINKED TO TROPICAL
STORM/FUTURE HURRICANE ILEANA AS SHE PARALLELS THE SOUTHERN BAJA
COAST 350 MILES OFFSHORE THURSDAY AND FRIDAY.
THE GFS MODEL...AND TO A MUCH LESSER EXTENT THE EUROPEAN MODEL...
FORECASTS A PROLONG PERIOD OF RELATIVELY STRONG AND SLIGHTLY
DIFLUENT 300/250 MB WINDS ACROSS SOUTH CENTRAL AZ FRIDAY AND THE
WEEKEND. UPPER LEVEL SUPPORT WITH INCREASED MOISTURE WILL LEAD TO A
RENEWED THREAT OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL
ARIZONA FRIDAY AND THE WEEKEND. PRECIP THREATS WILL END IN SOUTHEAST
CA THIS PERIOD.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...
TIGHTENED SURFACE PRESSURE GRADIENT BETWEEN EASTERN AZ AND THE
COLORADO RIVER COUPLED WITH DEEP EASTERLY FLOW ALOFT WILL PERSIST
SOUTHEASTERLY WINDS FOR THE PHOENIX AREA TERMINALS THROUGH MUCH OF
THE DAY. THIS PATTERN WILL EITHER DELAY OR PREVENT WESTERLY WINDS TO
THIS AFTERNOON AND EVENING. ANY AFTN STORMS EXPECTED OVER THE
SURROUNDING HIGHER TERRAIN...WITH LITTLE TO NO CHANCES FOR
DEVELOPMENT BACK INTO THE METRO AREA TONIGHT.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FEW TO SCT SKIES WILL LINGER WITH LIGHT DIURNAL WINDS. WINDS TO
BECOME SOUTHEASTERLY THROUGH THE DAY WITH CONTINUED PASSING HIGH
LEVEL CLOUDS THROUGH THE AFTERNOON. ISOLATED CHANCE FOR SHOWER/STORM
DEVELOPMENT IN THE AFTERNOON...HOWEVER HAVE NOT INCLUDED MENTION IN
THE MORNING TAF PACKAGE.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
UPPER LEVEL HIGH PRESSURE WILL REPOSITION FURTHER TO THE EAST
THURSDAY AND FRIDAY...ENABLING ADDITIONAL MOISTURE TO WORK INTO
EAST-CENTRAL ARIZONA. THIS WILL KEEP A SLIGHT CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS IN THE FORECAST FOR THURSDAY INTO THE
EARLY PART OF THE WEEKEND. STORM CHANCES HOWEVER WILL BE CONFINED
EAST OF THE LOWER COLORADO RIVER VALLEY FRIDAY THROUGH THE
WEEKEND...AS DRIER AIR MOVES IN FROM THE WEST. WINDS WILL BE
PREDOMINATELY SOUTHWEST THURSDAY AND FRIDAY...BEFORE BECOMING MORE
SOUTHERLY FOR THE WEEKEND. MINIMUM HUMIDITIES IN THE LOWER DESERTS
WILL BE IN THE TEENS THURSDAY AND FRIDAY AND THEN TREND INTO THE
MID 20S OVER THE WEEKEND.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...VASQUEZ/MO
AVIATION...NOLTE
FIRE WEATHER...MCLANE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
215 PM MDT TUE AUG 28 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 214 PM MDT TUE AUG 28 2012
SATELLITE IMAGERY AND RUC ANALYSIS SHOW A SMALL VORT MAX OVER THE
NORTHERN PORTION OF THE UNCOMPAHGRE PLATEAU...BETWEEN GATEWAY AND
GRAND JUNCTION...MOVING NE AND ENHANCING CONVECTION OVER THE
BOOKCLIFFS AND TAVAPUTS PLATEAUS IN EASTERN UT AND WESTERN CO.
THIS FEATURE WILL CONTINUE MOVING NE AND PROVIDE A MINOR FOCUS FOR
CONVECTIVE DEVELOPMENT AS IT DOES SO. THUS FAR...SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ONLY OVER THE MOUNTAINS AS EXPECTED.
LATE THIS AFTERNOON AND EARLY EVENING...OUTFLOWS SHOULD BEGIN TO
PUSH SOME CONVECTION INTO THE VALLEYS OR PROVIDE THE LIFT SO
THUNDERSTORMS CAN DEVELOP OVER THE LOWER ELEVATIONS. AFTER SUNSET
IT ALL SHOULD BEGIN DISSIPATING.
NOT MUCH CHANGE PREDICTED THROUGH WEDNESDAY NIGHT. THE RIDGE WILL
REMAIN CENTERED OVER COLORADO WITH NO STRONG MONSOONAL TAP
INDICATED. MOISTURE WILL CONTINUE TO RECYCLE BENEATH THE RIDGE...
PRODUCING A GRADUAL INCREASE IN DIURNAL SHOWERS AND THUNDERSTORMS
...MAINLY OVER THE MOUNTAINS. MAX AND MIN TEMPS WILL SHOW LITTLE
CHANGE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 214 PM MDT TUE AUG 28 2012
HIGH PRESSURE THAT HAS BEEN CENTERED OVER THE CENTRAL ROCKIES JUMPS
TO THE EASTERN USA THU AS IT GETS PINCHED BETWEEN THE REMNANTS OF
HURRICANE ISAAC AND A LARGE TROUGH OVER THE PAC NW. HOWEVER...
LITTLE CHANGE IN OUR SENSIBLE WEATHER IS EXPECTED THU-SAT WITH A
CONTINUATION OF MAINLY AFTERNOON/EARLY EVENING SHOWERS AND
THUNDESTORMS EACH DAY. WHILE MOISTURE ASSOCIATED WITH ISAAC WILL
REMAIN FAR TO OUR EAST...LINGERING MONSOONAL MOISTURE AROUND 3/4
INCH OR BETTER OF PRECIPITABLE WATER MEANS LOCALLY HEAVY RAIN WILL
STILL BE POSSIBLE.
AS SHORTWAVES EJECT FROM THE PAC NW MEAN TROUGH AND ACROSS THE
NORTHERN ROCKIES...THE 12Z GFS SHOWS A DRIER WESTERLY FLOW BECOMING
DOMINANT BY SUNDAY. 12Z ECMWF IS SLOWER WITH ANY DRYING BUT SHOWS
THE SAME TREND. THIS SHOULD LEAD TO LESS THUNDERSTORM ACTIVITY
SUNDAY THROUGH TUESDAY. MODELS SHOW THE RIDGE BUILDING BACK INTO
AZ/NM BY TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON)
ISSUED AT 214 PM MDT TUE AUG 28 2012
LOCAL MVFR CIGS AND VSBYS ARE EXPECTED OVER THE MOUNTAINS THROUGH
ABOUT 05Z...ASSOCIATED WITH SCATTERED SHOWERS AND THUNDERSTORMS.
THE CHANCE OF MVFR CONDITIONS AFFECTING ANY OF THE TAF SITES IS 10
PERCENT OR LESS. SIMILAR ACTIVITY IS EXPECTED WED AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...CC
LONG TERM...JAD
AVIATION...CC
AREA FORECAST DISCUSSION
NWS MIAMI FL
143 PM EDT TUE AUG 28 2012
.AVIATION...
SCATTERED TO NUMEROUS SHOWERS/TSTMS WILL CONTINUE TO DEVELOP AND
BECOME CONCENTRATED OVER THE NORTHERN AND NORTHEASTERN AREAS FROM
THE LAKE TO BROWARD REGION. WILL INCLUDE VCTS WORDING IN THE
PBI/FLL TAFS FOR NOW AND UPGRADE AS CONDITIONS WARRANT. PERIODS
WITH SUB VFR CIGS/VSBYS ALONG WITH GUSTY WINDS ASSOCIATED WITH ANY
HEAVY SHOWER/TSTM WILL REMAIN POSSIBLE THROUGH THE EVENING PERIODS
TODAY BEFORE TRENDING DOWN OVERNIGHT TONIGHT. WINDS WILL REMAIN
MOSTLY OUT OF THE SOUTHERLY DIRECTION TODAY...THEN BEGIN TO BACK
TOWARD THE ESE BY THIS TIME TOMORROW. AS A RESULT...SHOULD SEE THE
AFTERNOON CONVECTION BEGINNING TO SHIFT BACK TOWARD THE INLAND AND
WESTERN SECTIONS OF THE FL PENINSULA WEDNESDAY AFTERNOON/EVENING. 85/AG
&&
.PREV DISCUSSION... /ISSUED 1041 AM EDT TUE AUG 28 2012/
UPDATE...
THE BIG CONCERN FOR THIS AFTERNOON IS ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ACROSS PALM BEACH AND BROWARD COUNTY. A RAINBAND
REMAINS OFFSHORE OF CENTRAL FLORIDA OVER THE ATLANTIC WATERS THIS
MORNING. MODELS ARE INDICATING THAT THE MOISTURE GRADIENT WILL
SHIFT TO THE WEST OVER THE EAST COAST THIS AFTERNOON AS HIGH
PRESSURE BUILDS TO THE WEST. THE HRRR SHOWS THAT NUMEROUS TO
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DEVELOP IN THESE AREAS
ONCE AGAIN THIS AFTERNOON. SO BUMPED UP POPS TO 70-80 PERCENT
ACROSS PALM BEACH AND BROWARD COUNTIES...AND INCREASED QPF AMOUNTS
FOR THESE AREAS. ANY ADDITIONAL RAINFALL WILL EXACERBATE THE
FLOODING CONDITIONS IN THESE COUNTIES AS THERE IS STILL STANDING
WATER AND ONGOING FLOODING. SO THE FLOOD WATCH AND AREAL FLOOD
WARNING WILL CONTINUE THROUGH THIS EVENING FOR BROWARD AND PALM
BEACH COUNTY. KEPT POPS THE SAME FOR THE REST OF THE REGION...WITH
SCATTERED TO NUMEROUS SHOWERS AND STORMS POSSIBLE.
THE 12Z SOUNDING THIS MORNING SHOWED A PWAT OF ALMOST 2.4 INCHES.
A CONSERVATIVE TEMPERATURE OF 88 DEGREES AND DEWPOINT OF 76 SHOWS
OVER 4000 J/KG OF CAPE THIS AFTERNOON. SO BUMPED UP THE THREAT FOR
SEVERE STORMS THIS AFTERNOON...WITH THE MAIN THREAT BEING
DOWNBURSTS DUE TO WATER LOADING. MADE SOME MINOR ADJUSTMENTS TO
TEMPERATURES AND CLOUD COVER ACROSS THE REGION TODAY.
PREV DISCUSSION... /ISSUED 406 AM EDT TUE AUG 28 2012/
.ANOTHER WET DAY TODAY BEFORE DRIER WEATHER RETURNS TO SOUTH FLORIDA...
SHORT TERM...
TROPICAL STORM ISAAC IS STILL FORECAST BY THE NATIONAL HURRICANE
CENTER TO MOVE NORTHWEST TOWARDS LOUISIANA COAST TODAY. AT THE SAME
TIME...HIGH PRESSURE WILL BE SLOWLY BUILDING INTO THE AREA FROM
THE WESTERN ATLANTIC WATERS TODAY. THIS WILL ALLOW FOR THE
STEERING FLOW TO REMAIN SOUTHERLY OVER THE CWA KEEPING THE DEEP
TROPICAL MOISTURE IN PLACE. THE LATEST HIGH RESOLUTION RAPID
REFRESH PRECIP MODEL (HRRR) IS ALSO SHOWING THAT THERE COULD BE A
FEW FAR FEEDER BANDS FROM ISAAC SETTING UP OVER THE FLORIDA
PENINSULA. SO WILL KEEP SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS OVER THE CWA TODAY ALONG WITH LOCALLY HEAVY
RAINFALL. THIS WILL ALSO LEAD TO MORE FLOOD PROBLEMS OVER PALM
BEACH AND BROWARD COUNTIES TODAY. MORE ON THIS IN THE HYDRO
SECTION BELOW.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA FROM THE
WESTERN ATLANTIC WATERS TONIGHT INTO THURSDAY ALLOWING FOR THE
STEERING FLOW TO BECOME EASTERLY BY LATE TONIGHT. THIS WILL ALSO
ALLOW FOR SOME DRIER AIR TO WORK INTO THE CWA FROM THE ATLANTIC
WATERS WITH THE PWAT VALUES DROPPING FROM 2.3 INCHES TODAY DOWN TO
1.8 INCHES FOR WEDNESDAY INTO THURSDAY (WHICH IS NEAR NORMAL FOR
THIS TIME OF YEAR). SO WILL KEEP THE SCATTERED POPS OVER THE CWA
FOR WEDNESDAY AND THURSDAY WITH THE HIGHEST POPS OVER THE INTERIOR
AND WEST COAST AREAS.
LONG TERM...
THE HIGH WILL REMAIN OVER THE WESTERN ATLANTIC WATERS WHILE
EXTENDING INTO THE FLORIDA PENINSULA THIS WEEKEND KEEPING THE
EASTERLY STEERING FLOW IN PLACE. SO WILL CONTINUE TO SHOW THE
TYPICAL SUMMER TIME WEATHER PATTERN OVER SOUTH FLORIDA WITH MAINLY
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS EACH
DAY.
MARINE...
THE WIND DIRECTION TODAY WILL BE SOUTHERLY TODAY BEFORE SWINGING
TO A SOUTHEAST DIRECTION TONIGHT...THEN AN EASTERLY DIRECTION BY
WEDNESDAY. THE WIND SPEEDS OVER MOST OF THE LOCAL WATERS TODAY
WILL BE 15 TO 20 KNOTS BEFORE DECREASING TO 15 KNOTS OR LESS BY
TONIGHT. THE ONLY EXCEPTION TO THIS IS FOR THE GULF WATERS OF
SOUTH FLORIDA...WHERE THE SPEEDS WILL REMAIN ABOVE 20 KNOTS TODAY
BEFORE DECREASING TO 15 TO 20 KNOTS TONIGHT.
THIS WILL ALLOW FOR THE SEAS IN THE ATLANTIC WATERS TO FALL FROM 4
TO 6 FEET THIS MORNING DOWN TO 1 TO 3 FEET BY THIS EVENING. THE
NEAR-SHORE SEAS IN THE GULF WATERS WILL REMAIN BE 4 TO 6 FEET
THIS MORNING FALLING TO 1 TO 3 FEET BY THIS EVENING...WHILE THE
OFFSHORE SEAS WILL BE 7 TO 9 FEET THIS MORNING FALLING TO 5 TO 7
FEET BY THIS EVENING. THEREFORE...THE SCA WILL REMAIN UP FOR THE
GULF WATERS TODAY WHILE REST OF THE LOCAL WATERS WILL BE DROP AND
REPLACE BY SCEC FOR TODAY.
FIRE WEATHER...
THE RELATIVE HUMIDITIES WILL REMAIN WELL ABOVE THE 35 PERCENT
CRITICAL VALUE FOR THIS WEEK OVER SOUTH FLORIDA. SO NO PROBLEMS
ARE EXPECTED WITH THE FIRE WEATHER FOR SOUTH FLORIDA THIS WEEK.
HYDROLOGY...
TOTAL RAINFALL AMOUNTS OF 8 TO 13 INCHES HAVE BEEN REPORTED OVER
PALM BEACH COUNTY SINCE EARLY SUNDAY MORNING WITH DOPPLER RADAR
SHOWING BETWEEN 10 TO 20 INCHES FROM THE RAIN BANDS OF ISAAC. IN
BROWARD COUNTY...TOTAL RAINFALL AMOUNTS OF 8 TO 10 INCHES HAVE
BEEN REPORTED WITH DOPPLER RADAR SHOWING BETWEEN 8 TO 15 INCHES.
THESE RAINFALL AMOUNTS HAVE LEAD TO MAJOR FLOODING PROBLEMS IN
PORTIONS OF METRO PALM BEACH AND METRO BROWARD COUNTIES. OVER THE REST
OF SOUTH FLORIDA...TOTAL RAINFALL AMOUNTS OF 2 TO 5 INCHES HAVE
BEEN REPORTED WITH DOPPLER RADAR SHOWING BETWEEN 2 TO 8 INCHES.
WITH POSSIBLE ADDITIONAL HEAVY RAINFALL TODAY OVER SOUTH FLORIDA
AND MAJOR FLOODING PROBLEMS ON GOING OVER PORTIONS OF METRO PALM
BEACH AND METRO BROWARD COUNTIES...THE FLOOD WATCH WILL BE
EXTENDED UNTIL 8 PM THIS EVENING FOR PALM BEACH AND BROWARD
COUNTIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 90 77 90 / 40 30 20 30
FORT LAUDERDALE 78 90 78 89 / 30 30 20 20
MIAMI 77 90 78 90 / 20 30 20 20
NAPLES 76 90 76 90 / 20 40 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR COASTAL BROWARD-
COASTAL PALM BEACH-INLAND BROWARD-INLAND PALM BEACH-METRO
BROWARD-METRO PALM BEACH.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR COASTAL
BROWARD-COASTAL COLLIER-COASTAL MIAMI DADE-COASTAL PALM
BEACH.
AM...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
105 PM EDT TUE AUG 28 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 502 AM EDT TUE AUG 28 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE SRN/CNTRL ROCKIES INTO THE CNTRL PLAINS AND A TROUGH OVER NE
CANADA RESULTING IN NW FLOW THROUGH THE UPPER GREAT LAKES. AT THE
SFC...HIGH PRES EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR
INTO NRN WI. IR LOOP SHOWED THAT NRLY FLOW HAS BROUGHT SOME PATCHY
CLOUDS INTO UPPER MI WHILE MORE EXTENSIVE CLOUDS REMAINED NORTH OF
LAKE SUPERIOR.
TODAY...MODELS SUGGEST THAT ENOUGH MOISTURE WILL LINGER OVER THE
AREA SO THAT DAYTIME HEATING/MIXING WILL SUPPORT SCT-BKN CU BENEATH
A STRENGTHENING INVERSION AROUND 800 MB. 850 MB TEMPS IN THE 10C TO
12C RANGE WILL SUPPORT MAX READINGS IN THE MID TO UPPER 70S INLAND.
A WEAK GRADIENT WILL ALLOW LAKE BREEZES TO DEVELOP DURING THE
AFTERNOON KEEPING TEMPS CLOSER TO 70 ALONG LAKE SUPERIOR.
TONIGHT...WITH HIGH PRES BUILDING INTO ERN UPPER MI AND LOWER
MI...WEAK SRLY FLOW WILL DEVELOP. HOWEVER...WINDS SHOULD REMAIN
DECOUPLED AND ALLOW DECENT RADIATIONAL COOLING WITH INLAND MIN TEMPS
DROPPING TO AROUND 50.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 502 AM EDT TUE AUG 28 2012
SW LOW LEVEL FLOW INCREASES THROUGH THE DAY WED AS AN UPPER RIDGE
AXIS MOVES TO JUST W OF THE CWA BY 00Z THU. A SHORTWAVE TROUGH WILL
MOVE INTO WRN CANADA/NW CONUS WED...RESULTING IN A SFC LOW OVER SRN
SASK AND A TROUGH LEEWARD OF THE ROCKIES. WITH WAA AND HEIGHT RISES
AHEAD OF THIS SYSTEM...850MB TEMPS INCREASE TO AROUND 20C W AND 16C
E BY 00Z THU AS A IMPRESSIVE EML MOVES INTO THE AREA. 850MB TEMPS
START THE DAY A GOOD 5-6C COOLER...SO WE SHOULD NOT BE ABLE TO
ACHIEVE THE FULL POTENTIAL OF THE 20-16C 850MB TEMPS...ESPECIALLY
SINCE WE MAY NOT MIX AS HIGH AS THE WARMEST TEMPERATURES ALOFT.
HIGHS WED SHOULD BE IN THE MID 80S TO AROUND 90 WEST HALF...AND IN
THE MID 70S TO MID 80S EAST HALF. WARMEST TEMPS FAR WEST AND COOLEST
DOWN WIND OF LAKE MICHIGAN WITH A SSW WIND. LOW LEVEL MOISTURE
CONTINUES TO VARY BETWEEN MODELS...WITH THE 00Z/28 GFS BEING ON THE
HIGH SIDE /1000-700MB RH STILL UNDER 60 PERCENT/ AND THE 00Z/28 NAM
ON THE LOW SIDE /LESS THAN 45 PERCENT 1000-700MB RH/. USING A MORE
MODERATED BLEND OF THE TWO ALONG WITH OTHER MIDDLE OF THE ROAD
GUIDANCE...CONDITIONS WILL LEAD TO MIN SFC RH VALUES OF 30 TO 45
PERCENT. SFC WINDS SHOULD BE FROM THE SSW AT 10-15KTS WITH GUSTS OF
15-20KTS.
THU WILL BE THE HOTTEST DAY OF THE WEEK BENEATH THE PEAK OF THE EML
MOVING OVERHEAD AND THE 500MB RIDGE AXIS MOVING THROUGH. MODEL
GUIDANCE VARIES WITH 850MB TEMPS BETWEEN 22C-26C. HIGH TEMPS IN THE
80S TO MID 90S SHOULD BE ABLE TO BE REALIZED /COOLEST DOWNWIND OF
LAKE MICHIGAN/. SW LOW LEVEL FLOW WILL BE STRONGER AS THE SFC TROUGH
MOVES TO JUST W OF THE CWA BY 00Z FRI. SW SFC WINDS WILL BE AROUND
15KTS WITH GUSTS AS HIGH AS 30-35KTS POSSIBLE. TEMPERATURES AND MORE
SO WINDS WILL BE HIGHLY DEPENDENT ON HOW HIGH WE CAN MIX. MOST
MODELS SHOW US MIXING TO AROUND 850MB...WHERE THEY HAVE WINDS OF
AROUND 35KTS. MODELS ALSO AGREE IN SHOWING ERN UPPER MI SEEING
INCREASED 850MB WINDS...SO IT MAY VERY WELL BE GUSTIER THERE. GALE
POTENTIAL WILL NEED TO BE MONITORED OVER LAKE MI NEARSHORE
ZONES...BUT GIVEN STRONG WAA IT APPEARS LESS LIKELY. VERY DRY
MID/LOW LEVELS WILL AGAIN LEAD TO MIN SFC RH GENERALLY IN THE 30-40
PERCENT RANGE /EXCEPT HIGHER IN THE 40-50 PERCENT RANGE DOWNWIND OF
LAKE MICHIGAN/...SO FIRE WEATHER CONCERNS WILL BE MORE ELEVATED.
AFTER THE PASSAGE OF THE SHORTWAVE THU AND COLD FRONT THU
NIGHT...SFC HIGH PRESSURE AND UPPER RIDGING BECOME MORE DOMINANT
OVER THE CWA THROUGH SAT. HIGH TEMPS FRI STILL LOOK ABOVE NORMAL AS
MODELS SHOW 850MB TEMPS OF 15-20C BUT WITH MORE WNW LOW LEVEL WINDS.
TEMPS SAT LOOK A FEW OF DEGREES COOLER THAN FRI. MODELS THEN SHOW A
STRONGER SHORTWAVE MOVING INTO WRN ONTARIO LATE SUNDAY THROUGH
MON...BUT WITH MODELS INHERENT INABILITY TO FORECAST TROPICAL
SYSTEMS...CONFIDENCE DECREASES SHARPLY AS THE REMNANTS OF ISAAC ARE
FORECAST TO BE S OF OR ENCROACHING UPON THE CWA LATE SAT THROUGH
SUN. THE FORECAST FOR SUN AND MON WILL BE HIGHLY DEPENDENT ON WHERE
MOISTURE FROM ISAAC ENDS UP...SO WILL NOT HAVE TOO HIGH OF POPS AND
WILL GO WITH CONSENSUS OF MODELS AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 105 PM EDT TUE AUG 28 2012
DIURNAL CUMULUS AFFECTING ALL SITES THIS AFTERNOON SHOULD DISSIPATE
EARLY THIS EVENING WITH LOSS OF HEATING. DRY AIR AND LIGHT WINDS
OVERNIGHT WILL ALLOW FOR ABUNDANT RADIATIONAL COOLING AWAY FROM LAKE
SUPERIOR. EXPECTATION IS THAT SAW AND IWD WILL SEE FOG
DEVELOP...WHILE CMX REMAINS WARM ENOUGH TO PREVENT FOG. WINDS MAY
INCREASE SLIGHTLY AT IWD AFTER MIDNIGHT AND COULD BE ENOUGH TO LIMIT
FOG TO ONLY MVFR LEVELS. HOWEVER...AT SAW...CALM WINDS COULD CAUSE
PERIODS OF DENSE FOG. BROUGHT FORECAST VIS DOWN TO 1SM
OVERNIGHT...BUT THIS MAY NEED TO BE LOWERED IF MOISTURE DOES NOT MIX
OUT AS MUCH AS FORECAST THIS AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT TUE AUG 28 2012
QUIET CONDITIONS OVER THE MARINE AREAS THROUGH WEDNESDAY AS HIGH
PRESSURE BUILDS OVER THE GREAT LAKES REGION WITH LIGHT WINDS
EXPECTED. SOUTHWESTERLY WINDS WILL STRENGTHEN BY WEDNESDAY NIGHT AND
THURSDAY AHEAD OF A LOW PRESSURE SYSTEM OVER ONTARIO. HOWEVER...WITH
INCREASING STABILITY IN THE WAA REGIME WINDS ARE EXPECTED TO REMAIN
IN THE 15 TO 25 KT RANGE OVER THE SE HALF OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...TK
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
413 PM CDT TUE AUG 28 2012
.DISCUSSION...
/UPDATE FOR AFTERNOON TRENDS ISSUED AT 233 PM CDT TUE AUG 28 2012/
VARIOUS MESO GUIDANCE CONTINUE TO SHOW SHOWER/STORM REDEVELOPMENT
LATE THIS AFTERNOON OR EARLY THIS EVENING. THIS MORNING`S
CONVECTION HAS YET TO FULLY CLEAR THE AREA AND THE CURRENT VISIBLE
SATELLITE TRENDS SEEMS MORE FAVORABLE FOR SOUTHEAST MINNESOTA.
ALTO CU LOOKS LESS IMPRESSIVE IN AREAS NEAR AND WEST OF THE TWIN
CITIES METRO...AND WESTERN MN IS CLEAR. WE TRIED TO BETTER DEFINE
THE POPS THIS EVENING AND CARRY SCATTERED SHOWERS/STORMS AFTER 00Z
FOR SOUTHEAST PORTIONS OF THE FORECAST AREA. HOWEVER...THIS STILL
MIGHT BE MORE OF AN ISSUE FOR ARX AND DMX FORECAST AREAS. CURRENT
TEMP TRENDS AREN`T TOO BAD FOR WHAT HAS BEEN A TRICKY FORECAST
TODAY GIVEN THE EARLY CLOUDS...FOLLOWED BY CLEARING. WE ARE
RUNNING OUT OF HEATING...SO DON`T SEE MUCH MORE THAN 3 TO 4
DEGREES OF WARMING. &&
BIGGEST CONCERN THIS FORECAST PERIOD WOUND UP BEING FIRE WEATHER
CONCERNS FOR THURSDAY...WHICH IS BEGINNING TO BECOME QUITE THE
TRICKY FORECAST. WILL ALSO HAVE CONTINUED THUNDERSTORM CONCERNS
GOING INTO TONIGHT AND AGAIN TO END THE LABOR DAY WEEKEND.
GOOD WARM FRONT TAKING SHAPE THIS AFTERNOON IN TERMS OF A WIND
SHIFT EXTENDING FROM JUST NORTH OF SIOUX FALLS DOWN THROUGH
FAIRMONT. PERSISTENT THOUGH WEAK H85 FLOW HAS CONTINUED THE WAA AND
WEAK LIFT NORTH OF THE FRONT. 20Z MESO ANALYSIS SHOWS A NICE BAND OF
2000-3000 J/KG OF MUCAPE ALIGNED BASICALLY ALONG THE MN RIVER. THE
RAP CONTINUES TO HOLD THIS CAPE GRADIENT IN PLACE AT 00Z...WITH A
NICE BURST OF THETA-E ADVECTION TO THE EAST OF IT. THIS IS RIGHT
WHERE THE HRRR HAS BEEN DEVELOPING ROUND 2 OF CONVECTION THIS
EVENING FOR THE LAST SEVERAL RUNS BETWEEN 22Z AND 01Z.
SPCWRF/NMM/ARW REFLECTIVITY FORECASTS ALSO SHOW AGREEMENT WITH THE
HRRR FORECAST...THOUGH THEY ALL DIFFER WITH TIMING/PLACEMENT OF
INDIVIDUAL CELLS AS TO BE EXPECTED. BECAUSE OF THIS...INCREASED
POPS FOR THIS EVENING. EXPECT GREATEST COVERAGE OF STORMS THROUGH
3Z BEFORE FORCING BEGINS BENDING TO THE SOUTHEAST AND OUT OF THE
AREA. HOPEFULLY WE DO GET SOME RAIN...OTHERWISE SOUTH CENTRAL MN
COULD HAVE SOME SERIOUS PROBLEMS COME THURSDAY.
TONIGHT THROUGH WEDNESDAY. WARM FRONT BASICALLY WASHES OUT ALONG
I-94 WEDNESDAY AND LLJ LOSSES ITS DEFINITION...SO THIS SHOULD NOT
ONLY SHUT OFF THE PRECIP...BUT CLEAR THINGS OUT. FOR
WEDNESDAY...USED SOME MIX DOWN OF THE ECMWF TO TWEAK THE HIGHS
THAT DAY...THIS RESULTED IN A SLIGHT COOLING OF TEMPS EAST WITH
CONTINUED MID 90S WEST AS THE WARM BUBBLE WITH THE RIDGE DOES NOT
BEGIN MAKING SIGNIFICANT IN ROADS INTO THE MPX CWA UNTIL WEDNESDAY
NIGHT.
THURSDAY. THIS IS WHERE MUCH OF THE EFFORT WAS SPENT IN THE FORECAST
TODAY BETWEEN COORDINATION OF FIRE PRODUCTS WITH NEIGHBORING OFFICES
AND TRYING TO SORT OUT WHAT IS ENDING UP TO BE A TRICKY FORECAST.
ONE TREND FROM ALL 12Z GUIDANCE WITH THIS DAY IS THAT THEY ALL SPED
UP THE MOVEMENT OF THE WEAK BOUNDARY THAT WILL BE WORKING ACROSS
THE MPX CWA THAT AFTERNOON. THIS CAME AS A BIT OF A SURPRISE GIVEN
THE WALL OF SUBSIDENCE IT WILL BE RUNNING INTO WITH THE SUB-
TROPICAL RIDGE TO THE SOUTH. THERE IS ACTUALLY FAIRLY DECENT MODEL
CONSENSUS WITH THE FRONT SETTING UP FROM ROUGHLY SIOUX FALLS UP TO
EAU CLAIRE BY 7 PM THURSDAY. BESIDE THAT...BEHIND THIS
BOUNDARY...THE MID LEVEL TEMP GRADIENT LOOKS TO BE FAIRLY STRONG.
THIS HELPS TO INDUCE A DECENT UPPER JET ALONG THE INTERNATIONAL
BORDER /90 TO 100 KTS/. GIVEN THIS JET/TEMP GRADIENT SETUP...THE
NAM/GFS/ECMWF ARE STARTING TO PAINT A FAIRLY CLOUDY PICTURE NORTH
OF THE BOUNDARY /MID-UPPER LEVEL CLOUDS/...WHICH COULD REALLY TAKE
A BIG WHACK OUT OF EXPECTED HIGHS FOR THURSDAY...ESPECIALLY OVER
CENTRAL MN. GIVEN ALL OF THIS...DID NUDGE THE FORECAST HIGHS DOWN
ALONG AND NORTH OF A LINE FROM ROUGHLY REDWOOD FALLS...THROUGH THE
TWIN CITIES AND OVER TOWARD LADYSMITH. 925-850 MB THERMAL RIDGE
FORECAST BY THE ECMWF TO SIT ACROSS SOUTH CENTRAL MN OVER TOWARD
EAU CLAIRE...AND THIS IS WHERE IT STILL LOOKS QUITE PLAUSIBLE TO
SEE HIGHS TOP 100. WILL LEAVE THE HEAT WATCH FOR THE TWIN CITIES
AS IS...BUT WE MAY BE ABLE TO JUST GET AWAY WITH AN ADVY THERE ON
SOUTH GIVEN THE SLIGHT DOWNWARD NUDGE IN PROJECTED HIGHS WITH THIS
FORECAST.
AS FOR FIRE WEATHER CONCERNS...THEY ARE QUITE HIGH FOR THURSDAY AS
THIS IS A FAIRLY CLASSIC SETUP FOR SEEING SIGNIFICANT RED FLAG
WEATHER CONDITIONS IN THIS AREA /RH LESS THAN 25 PERCENT WITH
SUSTAINED WINDS IN EXCESS OF 20 MPH IN MN AND 15 MPH IN WI/. EXPECT
DEEP MIXING OUT AHEAD OF THE BOUNDARY...WHICH SHOULD HELP DEWPS MIX
DOWN INTO THE 50S. COMBINE DEWPS IN THE 50S WITH TEMPS UP NEAR 100
AND THE PROJECTED HUMIDITIES DROP INTO THE 20 TO 25 PERCENT RANGE.
THE BIGGER QUESTION MARK FOR THIS DAY WILL BE THE WINDS. AS THE
BOUNDARY SAGS INTO THE AREA...THE PRESSURE GRADIENT WILL SLACKEN
CONSIDERABLY WITH WIND SPEEDS DROPPING WELL BELOW THRESHOLDS NOTED.
HOWEVER...GET SUFFICIENTLY OUT AHEAD OF THE FRONT...AND WE SHOULD HAVE
NO PROBLEM MEETING AND EXCEEDING WIND THRESHOLDS...AS 1000-850 MB
MEAN WIND SPEEDS INCREASE INTO THE 20-30KT RANGE...WHICH WILL
SUPPORT SW WIND GUSTS UP TO 35 MPH. PROBABLY HAVE FIRE WEATHER WATCH
A LITTLE TOO FAR NORTH...BUT GIVEN MAGNITUDE OF FIRE WEATHER
PARAMETERS AND UNCERTAINTY IN FORECAST...FELT MORE COMFORTABLE WITH
A BIT OF A BUFFER TO THE NORTH.
FRIDAY THROUGH LABOR DAY. BIG QUESTION MARK HERE IS WHERE DO THE
REMNANTS FOR ISAAC END UP. FOR ONCE...GUIDANCE AT 12Z ACTUALLY IN
GOOD AGREEMENT WITH WHERE THE REMNANTS WILL GO AFTER LAND
FALL...TAKING THE REMNANT CIRCULATION UP INTO MO BY SATURDAY...THEN
OVER TOWARD CENTRAL INDIANA BY SUNDAY. MAIN IMPACT WITH THIS PATH IS
THAT ANY OF ITS MOISTURE WILL REMAIN SE OF THE MPX CWA...WITH THE
MPX CWA LIKELY BATTLING SUBSIDENCE TO THE NW OF ISAACS REMAINS SAT
THROUGH SAT NIGHT. GFS/ECMWF STILL SHOW A FRONT WORKING ACROSS THE
CWA SUNDAY/SUNDAY NIGHT...THOUGH WITH THE HURRICANE REMNANTS
SOUTHEAST...WOULD NOT BE AT ALL SURPRISED IF THIS SPEED SLOWS
DOWN IN THE COMING DAYS. IN ADDITION...THESE REMNANTS SHOULD
CONSUME A LOT OF THE MOISTURE THAT WOULD OTHERWISE BE DESTINED FOR
THE FRONT...MEANING CURRENT POPS FOR SUNDAY INTO MONDAY ARE
PROBABLY A BIT OVERDONE /EVEN AT THEIR CURRENT 30-40 PERCENT
LEVEL/. AS FOR TEMPERATURES...STILL LOOKS GOOD TO SEE A BIT OF A
COOL DOWN FOR FRIDAY...BUT HEAT SHOULD QUICKLY BUILD BACK IN AHEAD
OF THE FRONT FOR SATURDAY AND SUNDAY...WITH HIGHS IN THE 80S AND
90S CONTINUING TO BE COMMON THROUGH THE WEEKEND. NO SIGNS OF A
COOL DOWN ON THE ECMWF UNTIL THE MIDDLE OF NEXT WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
HIGH CLOUDS CLEARING THIS AFTERNOON AND VFR EXPECTED THIS
EVENING. ONE WILD CARD IS FOR SHOWER/STORM REDEVELOPMENT LATE THIS
AFTERNOON. THE FOCUS FOR THIS IS MORE EAST/SOUTH CENTRAL MN INTO
SE MN...WHICH WOULD KEEP MOST SITES IN THE CLEAR. ALREADY SEEING
MID CLOUDS WHICH MIGHT BE A SIGN OF WHAT`S TO COME. PATCHY FOG NOT
OUT OF THE QUESTION AT A COUPLE SITES...BUT WINDS SHOULD REMAIN
HIGH ENOUGH TO KEEP THIS UNDER CONTROL.
KMSP...NOT HIGH CONFIDENCE IN SHOWERS LATE THIS AFTERNOON...BUT
METRO WILL BE CLOSE...SO INCLUDED IT IN THE TAF. SHOULD BE MORE OF
AN ISSUE FOR AREAS SOUTHEAST OF THE AIRPORT GROUNDS. WINDS BREEZY
THIS AFTERNOON AND SLOW TO DECREASE THIS EVENING. HANGING AROUND
8-10KTS FOR MUCH OF THE EVENING.
/OUTLOOK FOR KMSP/
THURSDAY...POSSIBLE MVFR FOG EARLY...THEN VFR.
WINDS SE AT 10KTS. FRIDAY...VFR. GUSTY WINDS SW AT 15G25KTS.
SATURDAY.... WINDS SSE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR BLUE EARTH-BROWN-CARVER-DAKOTA-FARIBAULT-
FREEBORN-GOODHUE-HENNEPIN-LE SUEUR-MARTIN-MCLEOD-NICOLLET-
RAMSEY-REDWOOD-RENVILLE-RICE-SCOTT-SIBLEY-STEELE-WASECA-
WASHINGTON-WATONWAN.
EXCESSIVE HEAT WATCH FROM THURSDAY MORNING THROUGH THURSDAY
EVENING FOR HENNEPIN-RAMSEY.
WI...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-ST. CROIX.
&&
$$
MPG/CLF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
308 PM CDT TUE AUG 28 2012
.DISCUSSION...
FORECAST CONCERNS CENTER AROUND HOT TEMPS...FIRE WEATHER
CONDITIONS...AND REMNANTS OF ISAAC.
LATEST WATER VAPOR IMAGERY AND 500MB RAP ANALYSIS SHOWS LARGE DOME
OF HIGH PRESSURE OVER THE CENTRAL CONUS WITH A WEAK IMPULSE ON TOP
RIDING OVER THE RIDGE OVER SOUTHEASTERN WYOMING. UPSTREAM...A
SHORTWAVE TROF CONTINUES TO MOVE ONTO THE WEST COAST. AT THE
SFC...WARM SOUTHWESTERLY FLOW EXTENDS OVER ALL OF THE FORECAST
AHEAD OF SFC LOW PRESSURE CENTERED OVER CENTRAL SOUTH DAKOTA.
ACCAS FIELD REMAINS OVER OUR NORTHERN COUNTIES WHERE MID LEVEL
MOISTURE IS PROGGED TO REMAIN OVERNIGHT AND INTO WEDNESDAY. SOME
VERTICAL MOTION IS PROGGED OVER THIS SAME AREA OVERNIGHT AS ERN
WYOMING WAVE RIDES THE RIDGE TOWARD THE AREA. WITH EXTREMELY DRY
LEVELS BELOW 650MB...DO NOT EXPECT ANY PCPN TO REACH THE GROUND IF
ANY CAN/DOES DEVELOP.
FOCUS THEN TURNS TO FIRE WEATHER CONDITIONS ACROSS OUR NORTHERN
COUNTIES WEDNESDAY AFTERNOON. RED FLAG WARNING CRITERIA WILL BE
VERY CLOSE...ESPECIALLY IF WE CAN MIX OUT OUR SFC DEWPOINTS. WITH
MODEST SOUTHWESTERLY LOW LEVEL FLOW...WE SHOULD MIX OUT TEMPS QUITE
WELL DURING THE AFTERNOON PUSHING HIGHS INTO THE LOWER 100S IN
OUR NORTH TO THE UPPER 90S ELSEWHERE. DO EXPECT SIMILAR READINGS
ON THURSDAY AS 850MB TEMPS AROUND THE SAME IN THE UPPER 20S WITH
STRONG SOUTHWESTERLY MIXING. AS A RESULT...WILL GO WITH A RED FLAG
WARNING IN THE NORTHWEST COUNTIES AND MAY NEED TO CONSIDER A
HEADLINE OF SORTS FOR THURSDAY AS WELL.
MODEL CONSENSUS BRINGS ISAAC REMANTS AS FAR NORTH AS OUR
SOUTHEASTERN TIER OF COUNTIES FRIDAY NIGHT INTO SATURDAY. AS A
RESULT...HAVE ADDED LOW POPS...INCREASED SKY COVER AND LOWERED
HIGHS SLIGHTLY. THIS SYSTEM WILL QUICKLY DRIFT EAST OF THE AREA
AND SOUTHWESTERLY UPPER LEVEL FLOW WILL FOLLOW WITH A FEW EMBEDDED
SHORTWAVES PROGGED TO TRAVEL ACROSS THE REGION. AS A RESULT...HAVE
CONTINUED SOME SMALL CHANCE POPS DAYS 6 & 7 BUT CONFIDENCE IS
FAIRLY LOW.
KERN
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDS ARE EXPECTED THROUGH THE PERIOD. VARIABLE MID LEVEL CLOUD
COVER IS EXPECTED...MAINLY ABOVE 10,000 FEET. GUSTY SOUTHWEST WINDS
THIS AFTERNOON WILL DECREASE LATE THIS AFTN AND EVENING AND BECOME
SOUTH.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING FROM 1 PM TO 9 PM CDT WEDNESDAY FOR NEZ011-012-
015>018-030>033-042.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
311 PM EDT TUE AUG 28 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT ALONG WITH
CLEARING SKIES AND COOL TEMPERATURES. THE HIGH WILL REMAIN ATOP THE
AREA THROUGH THURSDAY WITH CLEAR TO PARTLY CLOUDY SKIES AND DRY
WEATHER EXPECTED. ANOTHER COLD FRONT WILL BRING THE CHANCE OF A FEW
SHOWERS AND THUNDERSTORMS BY FRIDAY AS ADDITIONAL FRONTAL ENERGY
AFFECTS THE REGION...FOLLOWED BY A RETURN TO MILD AND DRY CONDITIONS
BY THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 310 PM EDT TUESDAY...GENERALLY QUIET WEATHER ON TAP FOR
TONIGHT AS COLD FRONT DEPARTS SOUTHEAST AND OFFSHORE WITH SURFACE
HIGH PRESSURE BUILDING INTO THE REGION. ANY LINGERING LIGHT
INSTABILITY SHOWERS/SPRINKLES ACROSS THE NORTHERN MOUNTAINS SHOULD
BE OVER BY SUNSET WITH EVENING CLOUDS GIVING WAY TO MAINLY CLEAR
SKIES AND LIGHT WINDS LATER TONIGHT. LOWS REFRESHINGLY COOL
GENERALLY IN THE 42 TO 52 RANGE WITH CUSTOMARY VARIABILITY (I.E.
NEAR 35 AT KSLK AND NEAR 60 ALONG LAKE CHAMPLAIN). DID OPT TO CUT
BACK ON AREAL COVERAGE OF FOG LATER TONIGHT WITH INCREASING
EVIDENCE OF DECENT MIXING ATOP THE NOCTURNAL PBL OVERNIGHT PER
LATEST RAP FCST SOUNDING PROFILES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 310 PM EDT TUESDAY...OUTSIDE PATCHY EARLY MORNING FOG...THE
QUIET STRETCH OF WEATHER THEN CONTINUES FOR WEDNESDAY INTO
THURSDAY AS AFOREMENTIONED SURFACE HIGH PRESSURE BUILDS ATOP AND
EAST OF THE AREA WITH FAIR AND DRY CONDITIONS CONTINUING. BLENDED
MODEL 925-850 MB THERMAL PROFILES SUPPORT HIGHS 67 TO 75 ON
WEDNESDAY...THEN CLIMBING BACK INTO THE UPPER 70S TO MID 80S BY
THURSDAY AS FLOW TRENDS BREEZY SOUTH/SOUTHWESTERLY. LINGERING
SHALLOW MID LVL RH SUPPORTS SCT FAIR WX CUMULUS IN THE MOUNTAINS
EACH AFTERNOON WITH THE VALLEYS BASICALLY REMAINING MOSTLY SUNNY.
BY THURSDAY NIGHT MODELS HAVE COME INTO MARGINALLY BETTER AGREEMENT
SHOWING ADDITIONAL FRONTAL ENERGY DROPPING SOUTH TOWARD THE REGION
AS UPPER TROUGHING BEGINS TO DIG SOUTHWARD ACROSS ERN CANADA.
COULD STAY FAIRLY BREEZY...ESP ACROSS NRN NY PER LATEST 925MB WIND
FIELDS SHOWING LOW LEVEL PRE-FRONTAL SOUTHWESTERLY JET IN THE 35
TO 45 KT RANGE DEVELOPING OVERNIGHT. OF COURSE SURFACE WINDS WILL
BE LIGHTER BUT PLAUSIBLY COULD SEE SOME GUSTS IN EXCESS OF 30 MPH
IN FAVORED AREAS OF THE NERN DACKS DURING THIS PERIOD. CLOUDS WILL
SLOWLY INCREASE LATER AT NIGHT (ESP NORTH) WITH APPROACH OF THE
BOUNDARY AND DID OFFER CONTINUITY WITH A LOW (20/30%) POP LATE
ACROSS THE NORTH TO ACCT FOR POSSBL -SHRA ACTIVITY ASSOCIATED WITH
THIS FEATURE. LOW TEMPERATURES CONSIDERABLY MILDER GIVEN MIXED
PBL/SOUTHERLY FLOW WITH GENERALLY 55-60 EXPECTED IN THE MTNS AND
60-65 IN THE VALLEYS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 310 PM EDT TUESDAY...GENERALLY QUIET AND PLEASANT WEATHER IS
EXPECTED FOR MUCH OF THE LONG TERM PERIOD WITH HIGH PRESSURE BEING
THE DOMINATING WEATHER FEATURE. TO START THE PERIOD ON FRIDAY...A
FRONTAL BOUNDARY ACROSS SOUTHERN CANADA WILL BE DROPPING ACROSS
THE NORTH COUNTRY THROUGH THE DAY. MOISTURE FIELDS ARE LACKING
WITH THIS SYSTEM SO DON`T THINK WE`LL SEE MUCH MORE THAN A FEW
ISOLATED TO SCATTERED SHOWERS OUT OF IT. ADDITIONALLY...THERE ARE
SOME TIMING DIFFERENCES BETWEEN THE NAM AND GFS IN REGARDS TO
FRONTAL PASSAGE. THE GFS IS FASTER...OFFERING MUCH COOLER 925MB
TEMPS THAN THE NAM. THIS FAR OUT THOUGH DETAILS ARE UNCERTAIN SO
WILL JUST GO WITH A BLEND FOR NOW WITH HIGHS GENERALLY IN THE LOW
TO MID 80S.
FOR FRIDAY NIGHT THROUGH THE HOLIDAY WEEKEND...HIGH PRESSURE BOTH AT
THE SURFACE AND ALOFT WILL DOMINATE THE NORTH COUNTRY`S WEATHER.
LOOK FOR GENERALLY CLEAR SKIES...HIGHS IN THE 70S AND LOWS IN THE
50S.
BY LATE EVENING MONDAY...REMNANT MOISTURE FROM HURRICANE ISAAC
WILL BEGIN TO POSSIBLY AFFECT THE REGION. THIS FAR OUT IT`S HARD
TO NAIL DOWN ANY DETAILS AT THE LOCAL LEVEL SO FOR NOW WILL JUST
OFFERING SOME CHANCE POPS...BUT CERTAINLY WILL BE WORTH KEEPING AN
EYE ON AS WE MOVE INTO THE HOLIDAY WEEKEND.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...MAINLY VFR CONDITIONS EXPECTED OVER THE
NEXT 24 HOURS EXCEPT FOR SOME IFR FOG AT KMPV/KSLK OVERNIGHT.
SCATTERED TO BROKEN CUMULUS OUT THERE THIS AFTERNOON...ALONG WITH
A FEW STORMS ACROSS SOUTHERN VERMONT. ONLY TERMINAL WITH A CHANCE
OF A STORM WILL BE KRUT WITHIN THE NEXT HOUR OR SO...BUT LOOKS TO
JUST PASS TO THE EAST. HAVE INCLUDED VCTS FOR AN HOUR THERE...ALONG
WITH A TEMPO FOR AN OUTFLOW OF ABOUT 25KTS. OTHERWISE...EXPECT
CUMULUS TO DISSIPATE LATER THIS EVENING WITH THE LOSS OF DAYTIME
HEATING ALONG WITH NORTHWEST WINDS DIMINISHING. LIGHT WINDS AND
CLEAR SKIES WILL ENSUE FOR THE OVERNIGHT HOURS WITH EXCEPTIONS AT
KMPV AND KSLK WHERE IFR FOG WILL FORM FROM 06/07Z THROUGH 12/13Z.
AFTER 12/13Z...ALL SITES BACK TO VFR UNDER GENERALLY CLEAR SKIES
WITH MAYBE JUST A FEW CLOUDS FORMING OVER THE MOUNTAINS TOWARDS
MIDDAY.
18Z WEDNESDAY THROUGH SUNDAY...
18Z WEDNESDAY THROUGH 06Z FRIDAY...VFR UNDER HIGH PRESSURE. LOCAL
IFR FOG POSSIBLE LATE NIGHT AND EARLY MORNING AT KSLK/KMPV.
06Z FRIDAY THROUGH 00Z SATURDAY...MAINLY VFR WITH CHANCE FOR MVFR
SHOWERS AS A FRONTAL BOUNDARY DROPS SOUTHWARD ACROSS THE REGION.
00Z SATURDAY THROUGH SUNDAY...VFR UNDER HIGH PRESSURE. LOCAL
IFR FOG POSSIBLE LATE NIGHT AND EARLY MORNING AT KSLK/KMPV.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...LAHIFF
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
309 PM EDT TUE AUG 28 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH NC FROM THE NORTHWEST THIS
AFTERNOON AND WILL MOVE INTO THE AREA THIS EVENING AND OVERNIGHT.
THE COLD FRONT WILL WORK ITS WAY SLOWLY SOUTH THROUGH THE AREA ON
WEDNESDAY...BEFORE BECOMING STATIONARY NEAR THE SOUTH CAROLINA
STATE LINE THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 1000 AM TUESDAY...
PRECIP IS EXPENDING ACROSS SC AND SOUTHEASTERN NC ALONG THE LEADING
EDGE OF A PLUME OF TROPICAL MOISTURE ASSOCIATED WITH TS ISAAC THIS
MORNING. 12Z RAOBS FROM KFFC...KCHS...AND KMHX ALL REPORT PW NOW IN
EXCESS OF 2 INCHES...UP TO 2.5 INCHES AT KCHS. THE LATEST RAP
SHOWS A REMNANT DISTURBANCE FROM CONVECTION NEAR FLORIDA ON MONDAY
MOVING INTO THE NC COASTAL PLAIN...WHICH IS WHERE THE STRONGER
CONVECTIVE ELEMENTS ARE LOCATED THIS MORNING. MEANWHILE...A COLD
FRONT STRETCHES FROM THE MID ATLANTIC STATES BACK WEST TOWARD THE
MID MS RIVER VALLEY REGION...AND WILL BEGIN TO BEND SOUTH ACROSS THE
APPALACHIANS INTO VA TODAY...APPROACHING THE NC/SC BORDER BY 00Z
THIS EVENING. NEAR TERM GUIDANCE SUGGESTS THE WESTERLY FLOW
OBSERVED AHEAD OF THE COLD FRONT WILL KEEP THIS PRECIP MOSTLY
FOCUSED FROM THE SOUTHERN PIEDMONT TOWARD THE COASTAL PLAIN THROUGH
THE EARLY AFTERNOON. BASED ON RADAR TRENDS...WE WILL INCREASE POPS
TO 70-80 PERCENT FROM ROUGHLY LAURINBURG TO GOLDSBORO.
NORTH OF HWY 64 TOWARD THE NC/VA BORDER...LESS CLOUDS AND STRONGER
INSOLATION ...WILL LEAD TO STRONGER HEATING AND AN AXIS OF
PRE-FRONTAL INSTABILITY THIS AFTERNOON...WHERE MLCAPE SHOULD
1000-1500 J/KG BASED ON MODIFIED RAP SOUNDINGS. STRONGER STORMS MAY
DEVELOP OVER THE NORTHERN PIEDMONT/COASTAL PLAIN AND SOUTHERN
VIRGINIA ALONG AND EXPECTED DIFFERENTIAL HEATING BOUNDARY AND/OR IN
THE VICINITY OF THE APPROACHING FRONT. TIMING BASED ON THE HRRR
WOULD BE 20Z OR AFTER. WHILE DEEP LAYER SHEAR IS WEAK OVER THE CWA
AT THE MOMENT...SPC MESOANALYSIS SHOWS 25-30KT NEAR THE FRONT OVER
NORTHERN VA WHERE STRONGER MID LEVEL FLOW RESIDES. COMBINED WITH
STRENGTHENING DCAPE ASSOCIATED WITH THE AFOREMENTIONED MID LEVEL DRY
AIR...A CLUSTERS OF STRONG TO SEVERE STORMS MAY DEVELOP OVER
SOUTHERN VA AND MOVE SOUTH INTO THE CWA....ALTHOUGH A WEAKENING
TREND WOULD BE EXPECTED AS THEY MOVE SOUTH INTO A LESS FAVORABLE
ENVIRONMENT AFTER SUNSET.
ADJUSTMENTS TO TEMPS WILL BE RELATIVELY MINOR...MAINLY LOWERING
HIGHS ACROSS THE SOUTH TO THE LOWER 80S...WITH UPPER 80S TO AROUND
90 ACROSS THE NORTH. -SMITH
AS OF 315 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
OVERALL MODEL CONSENSUS IS THAT THE FRONT WILL SAG SLOWLY SOUTHWARD
THROUGHOUT THE DAY ON WEDNESDAY...INVOF THE NC/SC BORDER BY 18 TO
21Z AS RIDGING BUILDS IN FROM THE WEST/NORTHWEST. ITS QUITE POSSIBLE
THAT WE COULD CONTINUE TO SEE A HEAVY RAIN THREAT ACROSS THE FAR
SOUTHERN COUNTIES...BUT MODELS HAVE REALLY CUT BACK QPF ACROSS THE
AREA WITH DRY AIR BEGINNING TO SPREAD INTO THE AREA FROM THE
NORTH/NORTHWEST. NOT ENTIRELY SOLD ON THIS QUICKER DRIER TREND...BUT
WILL LOWER POPS ACROSS THE NORTH ON WEDNESDAY...WITH THE MAIN
ACTIVITY EXPECTED SOUTH OF US 64. IT LATEST MODEL TRENDS ARE TO BE
BELIEVED...WEDNESDAY NIGHT COULD BE MOSTLY DRY...BUT AGAIN PREFER TO
EASE INTO THE FASTER TIMING OF DRYING THINGS OUT.
SEVERE THREAT LOOKS TO BE NEARLY ZERO GIVEN WIDESPREAD CLOUD
COVER/MOIST ENVIRONMENT. TEMPERATURES RANGING FROM MID 80S NORTH TO
TO LOWER 80S SOUTH. LOWS IN THE MID 60S NORTH TO NEAR 70 SOUTH.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 245 PM TUESDAY...
THU: 1022 MB SURFACE HIGH PRESSURE OVER LAKE HURON THIS AFTERNOON
WILL DRIFT SOUTHEASTWARD AND OFFSHORE THE MIDDLE ATLANTIC COAST ON
THURSDAY. NWP GUIDANCE IS IN GOOD AGREEMENT THAT THE PRECEDING LOW
LEVEL FRONTAL ZONE FORECAST TO MOVE THROUGH CENTRAL NC TONIGHT WILL
SETTLE TO NEAR THE SC STATE LINE BY THU MORNING...THEN PERHAPS
RETREAT SLIGHTLY NORTHWARD TOWARD THE SOUTHERN NC PIEDMONT WHILE
UNDERGOING FRONTOLYSIS IN RETURN SOUTHEASTERLY FLOW AROUND THE
HIGH...LATE THU INTO THU NIGHT. THE LOW LEVEL FRONTAL ZONE WILL BE
PROPELLED BY A STRONGLY POSITIVELY-TILTED TROUGH AXIS COMPOSED
ALMOST ENTIRELY OF SHEAR VORTICITY AND IS ACCORDINGLY DIFFICULT TO
IDENTIFY ON WV VAPOR IMAGERY THIS AFTERNOON...AND MAY NOT YET BE
WELL REPRESENTED BY NWP GUIDANCE...SO CONFIDENCE ON THE LOCATION OF
THE FRONT ON THU IS ONLY AVERAGE TO SLIGHTLY ABOVE AT THIS TIME. AS
SUCH...WILL MAINTAIN AN AFTERNOON SLIGHT TO CHANCE POP OVER THE
SOUTHERN PIEDMONT AND SANDHILLS TO ACCOUNT FOR THIS UNCERTAINTY...
BUT BOTH DRIER BL AND DEEP LAYER MOISTURE...AND SUBSIDENCE/CAPPING
ALOFT IN THE WAKE OF THE TROUGH AXIS ALOFT...SUGGESTS THE REMAINDER
OF CENTRAL NC SHOULD BE DRY. PROJECTED LOW LEVEL THICKNESS VALUES
AROUND 1410 METERS...WITH PARTLY CLOUDY (TO PERHAPS A PERIOD OF
MOSTLY SO INVOF THE FRONT NEAR THE SC STATE LINE)...SUPPORT HIGH
TEMPERATURES RELATIVELY UNIFORMLY IN THE MIDDLE 80S.
THU NIGHT: THE SURFACE RIDGE AXIS IS FORECAST TO EXPAND FROM
OFFSHORE WESTWARD ACROSS NC AND THE SOUTHERN/CENTRAL APPALACHIANS
OVERNIGHT...AS A FAIRLY STOUT MID LEVEL RIDGE CHARACTERIZED BY H7
HEIGHTS OF AROUND 321-322 DM MIGRATES SOUTHEASTWARD TOWARD THE
MIDDLE ATLANTIC STATES. EXCELLENT RADIATIONAL COOLING CONDITIONS
SHOULD ACCOMPANY THE EXPANDING RIDGE AXIS...BENEATH A MOSTLY CLEAR
SKY...WITH WIDE RANGING LOWS FROM THE LOWER TO UPPER 60S BETWEEN
RURAL/TYPICALLY COOLER AND URBAN AREAS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 PM TUESDAY...
FRI-SAT NIGHT: WARMER AND MAINLY DRY. THE AFOREMENTIONED MID LEVEL
RIDGE AND ASSOCIATED LOW LEVEL THERMAL RIDGE WILL DRIFT FROM INTO
THE MIDDLE ATLANTIC STATES/CAROLINAS FRI-SAT. FORECAST H85
TEMPERATURES ACCORDINGLY CLIMB TO AROUND 20-21C CENTERED OVER VA/NC
DURING THIS TIME...WHICH SHOULD SUPPORT HIGH TEMPERATURES IN THE
UPPER 80S TO LOWER 90S -- WARMEST SAT -- BOTH DAYS. LOWS WITHIN A
COUPLE OF DEGREES OF 70. CONVECTIVE POTENTIAL WILL REMAIN QUITE
LOW...AND HAS BEEN LEFT OUT OF THE FORECAST GIVEN THE SUBSIDENT AND
CAPPING INFLUENCE OF THE RIDGE ALOFT...DESPITE SHALLOW LOW LEVEL
CONVERGENCE WITHIN THE PIEDMONT SURFACE TROUGH AXIS AND BL MOISTURE
GRADIENT.
SUN-TUE: BASED ON THE LATEST NHC FORECAST POSITION OF THE REMNANTS
OF ISAAC OVER NORTHERN IN AT 12Z SUN...AND THE CONSENSUS OF GUIDANCE
MOVING THE SHEARED REMNANTS GENERALLY EASTWARD AROUND THE NORTHERN
PERIPHERY OF THE MID LEVEL RIDGE...IT APPEARS THAT SENSIBLE WEATHER
IMPACTS FOR CENTRAL WILL BE RELATIVELY MINIMAL. AS ISAAC BECOMES
ABSORBED IN THE WESTERLIES...A NORTHERN STREAM FRONTAL SYSTEM WILL
OVERTAKE THE SYSTEM AND DRAG AN ASSOCIATED SURFACE FRONTAL ZONE --
AND A RELATIVE MAXIMUM OF CONVECTIVE CHANCES (IN THE 30-40 PERCENT
RANGE) -- THROUGH CENTRAL NC IN THE MON-TUE TIME FRAME. HOWEVER...
SINCE THE MAIN BELT OF THE WESTERLIES IN THE NORTHERN STREAM AND
ASSOCIATED STEERING INFLUENCES IS FORECAST TO REMAIN NEAR THE
CANADIAN BORDER THROUGH THE PERIOD...FORECAST UNCERTAINTY REGARDING
THE TIMING AND TRACK OF THE REMNANTS IS AVERAGE TO BELOW; AND THIS
IS APPARENT BY THE WIDE MEDIUM RANGE MODEL SOLUTION SPREAD.
TEMPERATURES SHOULD ALSO COOL BACK TO MORE SEASONABLE LEVELS IN THE
MIDDLE TO UPPER 80S AS THE PRECEDING RIDGE ALOFT IS SUPPRESSED BY
THE NORTHERN STREAM/ISAAC REMNANTS.
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 150 PM TUESDAY...
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE SLOWLY NORTH TOWARD THE
SOUTHERN PIEDMONT AND SOUTHERN COASTAL PLAIN AS A PLUME OF TROPICAL
MOISTURE ASSOCIATED WITH HURRICANE ISAAC PUSHES NORTH INTO SC AND
SOUTHERN NC. MEANWHILE..A COLD FRONT IS MOVING SOUTH INTO VA...AND
WILL CONTINUE SOUTH INTO NC LATER THIS EVENING. SCATTERED SHOWERS
AND STORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT THIS
AFTERNOON AND POSSIBLY APPROACH THE TRIAD TERMINALS AND KRDU BY
22-00Z. SHOWERS AND ISOLATED THUNDERSTORMS ARE MORE LIKELY AROUND
KFAY AND MAY CONTINUE INTO THE OVERNIGHT HOURS AS THE COLD FRONT
SINKS FURTHER SOUTH INTO THE AREA. MODELS INDICATED WIDESPREAD
STRATUS WILL REDEVELOP RELATIVELY EARLY TONIGHT...BY 03-05Z...WITH
IFR CONDITIONS MOST LIKELY AT KRDU/KFAY/KRWI.
THE COLD FRONT IS FORECAST TO PUSH SOUTH TO NEAR THE NC/SC BORDER BY
WEDNESDAY MORNING...AND MODELS CONTINUE TO TREND DRIER ACROSS
CENTRAL NC. WHILE SHOWERS WOULD BE MORE PROBABLY AROUND
KFAY...CONFIDENCE IS TOO LOW FOR MENTION INT HE CURRENT TAF.
HOWEVER...MVFR CEILINGS MAY PERSIST AT KFAY IN THE VICINITY OF THE
FRONT AND BETTER LOW LEVEL MOISTURE.
RAIN CHANCES ARE EXPECTED TO SHIFT SOUTH OF THE AREA BY THURSDAY
WITH DRIER AIR FILTERING INTO THE AREA FROM THE NORTH. OUTSIDE OF
SOME MORNING FOG/STRATUS EACH MORNING...EXPECT PREDOMINATELY VFR
CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/SMITH
SHORT TERM...MWS/SEC
LONG TERM...MWS/SEC
AVIATION...CBL/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EDT TUE AUG 28 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL APPROACH NC FROM THE NORTHWEST THIS
AFTERNOON AND WILL MOVE INTO THE AREA THIS EVENING AND OVERNIGHT.
THE COLD FRONT WILL WORK ITS WAY SLOWLY SOUTH THROUGH THE AREA ON
WEDNESDAY...BEFORE BECOMING STATIONARY NEAR THE SOUTH CAROLINA
STATE LINE THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM TUESDAY...
PRECIP IS EXPENDING ACROSS SC AND SOUTHEASTERN NC ALONG THE LEADING
EDGE OF A PLUME OF TROPICAL MOISTURE ASSOCIATED WITH TS ISAAC THIS
MORNING. 12Z RAOBS FROM KFFC...KCHS...AND KMHX ALL REPORT PW NOW IN
EXCESS OF 2 INCHES...UP TO 2.5 INCHES AT KCHS. THE LATEST RAP
SHOWS A REMNANT DISTURBANCE FROM CONVECTION NEAR FLORIDA ON MONDAY
MOVING INTO THE NC COASTAL PLAIN...WHICH IS WHERE THE STRONGER
CONVECTIVE ELEMENTS ARE LOCATED THIS MORNING. MEANWHILE...A COLD
FRONT STRETCHES FROM THE MID ATLANTIC STATES BACK WEST TOWARD THE
MID MS RIVER VALLEY REGION...AND WILL BEGIN TO BEND SOUTH ACROSS THE
APPALACHIANS INTO VA TODAY...APPROACHING THE NC/SC BORDER BY 00Z
THIS EVENING. NEAR TERM GUIDANCE SUGGESTS THE WESTERLY FLOW
OBSERVED AHEAD OF THE COLD FRONT WILL KEEP THIS PRECIP MOSTLY
FOCUSED FROM THE SOUTHERN PIEDMONT TOWARD THE COASTAL PLAIN THROUGH
THE EARLY AFTERNOON. BASED ON RADAR TRENDS...WE WILL INCREASE POPS
TO 70-80 PERCENT FROM ROUGHLY LAURINBURG TO GOLDSBORO.
NORTH OF HWY 64 TOWARD THE NC/VA BORDER...LESS CLOUDS AND STRONGER
INSOLATION ...WILL LEAD TO STRONGER HEATING AND AN AXIS OF
PRE-FRONTAL INSTABILITY THIS AFTERNOON...WHERE MLCAPE SHOULD
1000-1500 J/KG BASED ON MODIFIED RAP SOUNDINGS. STRONGER STORMS MAY
DEVELOP OVER THE NORTHERN PIEDMONT/COASTAL PLAIN AND SOUTHERN
VIRGINIA ALONG AND EXPECTED DIFFERENTIAL HEATING BOUNDARY AND/OR IN
THE VICINITY OF THE APPROACHING FRONT. TIMING BASED ON THE HRRR
WOULD BE 20Z OR AFTER. WHILE DEEP LAYER SHEAR IS WEAK OVER THE CWA
AT THE MOMENT...SPC MESOANALYSIS SHOWS 25-30KT NEAR THE FRONT OVER
NORTHERN VA WHERE STRONGER MID LEVEL FLOW RESIDES. COMBINED WITH
STRENGTHENING DCAPE ASSOCIATED WITH THE AFOREMENTIONED MID LEVEL DRY
AIR...A CLUSTERS OF STRONG TO SEVERE STORMS MAY DEVELOP OVER
SOUTHERN VA AND MOVE SOUTH INTO THE CWA....ALTHOUGH A WEAKENING
TREND WOULD BE EXPECTED AS THEY MOVE SOUTH INTO A LESS FAVORABLE
ENVIRONMENT AFTER SUNSET.
ADJUSTMENTS TO TEMPS WILL BE RELATIVELY MINOR...MAINLY LOWERING
HIGHS ACROSS THE SOUTH TO THE LOWER 80S...WITH UPPER 80S TO AROUND
90 ACROSS THE NORTH. -SMITH
A POSITIVELY TILTED NORTHERN STREAM SHORTWAVE TROUGH EXTENDING FROM
SOUTHEAST CANADA INTO THE OHIO VALLEY WILL PROGRESS EAST THROUGH
THROUGH THE NORTHEAST AND NORTHERN MID-ATLANTIC REGION BY LATE
AFTERNOON. NWP MODEL GUIDANCE HAS SLOWED DOWN THE TIMING OF THE
ATTENDANT TRAILING SFC COLD FRONT INTO THE AREA...DELAYING ITS
ARRIVAL INTO THE NORTHERN/NORTHWEST PIEDMONT UNTIL AFTER 00Z THIS
EVENING. WHILE SATELLITE AND RADAR TRENDS INDICATE THAT THE MOISTURE
AND ASCENT IS RATHER PUNY ALONG THE SOUTHERN TAIL END OF THE
TRAILING SFC COLD FRONT CURRENTLY OVER PARTS OF KENTUCKY AND WESTERN
TN...THE FRONT WILL FIND A PLUME OF TROPICAL MARITIME AIRMASS (PWATS
2.0-2.25")IN PLACE ACROSS THE CAROLINAS....DISTRIBUTED POLEWARD INTO
THE REGION BY ISAAC`S EXPANSIVE WIND FIELD AND AN EMBEDDED
PERTURBATION OFF THE SC/GA COAST.
CURRENT THINKING IS THAT WE WILL SEE THE BEST CONVECTIVE COVERAGE
ACROSS THE SOUTHERN/SOUTHEASTERN PORTION OF THE FORECAST LATE THIS
MORNING AND INTO THE EARLY AFTERNOON...WITH AN OVERALL MINIMUM
ACROSS THE NORTHERN TIER UNTIL THE FRONT MOVES INTO THE AREA
AOA 00Z...WITH A GOOD CHANCE POPS EVERYWHERE OVERNIGHT AS THE
LOW-LEVEL CONVERGENCE ZONE AND RT ENTRANCE REGION JET DYNAMICS
INTERACT WITH THE TROPICAL AIRMASS.
SEVERE THREAT REMAINS LOWS GIVEN WEAK WINDS ALOFT AND MEAGER
INSTABILITY BETWEEN 500 TO 1000 J/KG. FLOODING CONTINUES TO BE THE
MAIN THREAT...ESPECIALLY ACROSS THE SOUTHEAST WITH IT POSSIBLE THAT
SOME AREAS COULD SEE 2 TO 4 INCHES POSSIBLE.
AS FAR AS TEMPERATURES...COULD SEE SOME OF THE WARMEST READINGS
ACROSS THE NORTH TODAY...DEPENDING ON CLOUD/SHOWER COVERAGE.
HIGHS IN THE MID TO UPPER 80S. OVERNIGHT LOWS IN THE MID TO UPPER
60S NORTH TO LOWER 70S SOUTH.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 315 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
OVERALL MODEL CONSENSUS IS THAT THE FRONT WILL SAG SLOWLY SOUTHWARD
THROUGHOUT THE DAY ON WEDNESDAY...INVOF THE NC/SC BORDER BY 18 TO
21Z AS RIDGING BUILDS IN FROM THE WEST/NORTHWEST. ITS QUITE POSSIBLE
THAT WE COULD CONTINUE TO SEE A HEAVY RAIN THREAT ACROSS THE FAR
SOUTHERN COUNTIES...BUT MODELS HAVE REALLY CUT BACK QPF ACROSS THE
AREA WITH DRY AIR BEGINNING TO SPREAD INTO THE AREA FROM THE
NORTH/NORTHWEST. NOT ENTIRELY SOLD ON THIS QUICKER DRIER TREND...BUT
WILL LOWER POPS ACROSS THE NORTH ON WEDNESDAY...WITH THE MAIN
ACTIVITY EXPECTED SOUTH OF US 64. IT LATEST MODEL TRENDS ARE TO BE
BELIEVED...WEDNESDAY NIGHT COULD BE MOSTLY DRY...BUT AGAIN PREFER TO
EASE INTO THE FASTER TIMING OF DRYING THINGS OUT.
SEVERE THREAT LOOKS TO BE NEARLY ZERO GIVEN WIDESPREAD CLOUD
COVER/MOIST ENVIRONMENT. TEMPERATURES RANGING FROM MID 80S NORTH TO
TO LOWER 80S SOUTH. LOWS IN THE MID 60S NORTH TO NEAR 70 SOUTH.
THURSDAY THROUGH FRIDAY NIGHT...MODELS ARE SLOWLY COMING INTO BETTER
AGREEMENT WITH RESPECT TO THE TRACK ON THE REMNANTS OF ISAAC...AT
LEAST THROUGH THE END OF THE WORK WEEK. IT APPEARS ISAAC WILL
PROGRESS VERY SLOWLY NORTHWARD ONCE IT MAKES LANDFALL NEAR
SOUTHEASTERN LA LATER TODAY...WITH IT PROGGED TO ONLY BE NEAR
NORTHERN LA BY LATE THURSDAY INTO EARLY FRIDAY. CLOSER TO HOME...A
WEAKENING FRONTAL SYSTEM IS PROGGED TO BE LOCATED NEAR THE SOUTHERN
PORTIONS OF THE FORECAST AREA TO START THURSDAY BEFORE MOVING EVEN
FURTHER SOUTH OF THE AREA BY FRIDAY AS HIGH PRESSURE BOTH AT THE
SURFACE AND ALOFT BUILD INTO THE REGION. MOISTURE CONTENT WILL STILL
BE RATHER HIGH ON THURSDAY...ESPECIALLY ACROSS THE SOUTH AND WEST
WHERE PWAT VALUES ARE PROGGED TO BE NEAR 2 INCHES. HOWEVER...
MOISTURE WILL BEGIN TO DECREASE LATE THURSDAY AS DRIER AIR MOVES IN
WITH THE BUILDING HIGH PRESSURE. WITH ALL OF THIS IN MIND...WILL SEE
A DOWNWARD TREND IN POPS FOR THIS TIME FRAME. FOR THURSDAY...THE
BEST CHANCE FOR PRECIP WILL BE ACROSS THE SOUTHWEST (MID CHANCE
POPS)...WITH ONLY MINIMAL POPS FURTHER TO THE NORTHEAST (WHERE IT
COULD VERY WELL STAY DRY). ON FRIDAY...WILL KEEP THE SAME POP
PATTERN (HIGHEST SOUTHWEST...LOWEST NORTHEAST) BUT WILL LOWER
OVERALL CHANCES TO NO MORE THAN SLIGHT CHANCE. WE WILL ALSO SEE A
WARMING TREND DURING THIS TIME FRAME AS HEIGHTS RISE ACROSS THE
REGION...WITH GENERALLY LOW/MID 80S ON THURSDAY AND MID/UPPER 80S BY
FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
THERE IS STILL QUITE OF BIT OF UNCERTAINTY FOR THE LONG TERM PERIOD
AS OUR WEATHER WILL ULTIMATELY DEPEND ON THE TRACK OF THE REMNANTS
OF ISAAC...WHICH THE MODELS ARE STILL HAVING TROUBLE WITH THIS FAR
OUT. OVERALL...MODELS TRACK THE REMNANTS OF ISAAC NORTH THROUGH THE
MS RIVER VALLEY...AROUND THE MID LEVEL RIDGE THAT WILL BE LOCATED
OVER THE MID ATLANTIC/SOUTHEAST US. MODELS BEGIN TO BREAK THIS RIDGE
DOWN ON SATURDAY AS A NORTHERN STREAM TROUGH MOVES ACROSS SOUTHERN
CANADA/NORTHERN NEW ENGLAND (HOWEVER THIS IS MUCH FASTER THAN
PREVIOUS RUNS). AS A RESULT...THE REMNANTS OF ISAAC BEGIN TO MOVE
EAST AND THEN MODELS SHOW THEM LINGERING ACROSS THE SOUTHEAST US
THROUGH EARLY NEXT WEEK. THIS WOULD RESULT IN INCREASING PRECIP
CHANCES FOR EARLY IN THE WEEKEND AND THEN PERSISTING THROUGH EARLY
NEXT WEEK. HOWEVER...DUE TO THE HIGH UNCERTAINTY...WILL GO NO HIGHER
THAN LOW END CHANCE UNTIL CONFIDENCE INCREASES. TEMPS WILL REMAIN
NEAR NORMAL THROUGH THE PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 150 PM TUESDAY...
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE SLOWLY NORTH TOWARD THE
SOUTHERN PIEDMONT AND SOUTHERN COASTAL PLAIN AS A PLUME OF TROPICAL
MOISTURE ASSOCIATED WITH HURRICANE ISAAC PUSHES NORTH INTO SC AND
SOUTHERN NC. MEANWHILE..A COLD FRONT IS MOVING SOUTH INTO VA...AND
WILL CONTINUE SOUTH INTO NC LATER THIS EVENING. SCATTERED SHOWERS
AND STORMS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT THIS
AFTERNOON AND POSSIBLY APPROACH THE TRIAD TERMINALS AND KRDU BY
22-00Z. SHOWERS AND ISOLATED THUNDERSTORMS ARE MORE LIKELY AROUND
KFAY AND MAY CONTINUE INTO THE OVERNIGHT HOURS AS THE COLD FRONT
SINKS FURTHER SOUTH INTO THE AREA. MODELS INDICATED WIDESPREAD
STRATUS WILL REDEVELOP RELATIVELY EARLY TONIGHT...BY 03-05Z...WITH
IFR CONDITIONS MOST LIKELY AT KRDU/KFAY/KRWI.
THE COLD FRONT IS FORECAST TO PUSH SOUTH TO NEAR THE NC/SC BORDER BY
WEDNESDAY MORNING...AND MODELS CONTINUE TO TREND DRIER ACROSS
CENTRAL NC. WHILE SHOWERS WOULD BE MORE PROBABLY AROUND
KFAY...CONFIDENCE IS TOO LOW FOR MENTION INT HE CURRENT TAF.
HOWEVER...MVFR CEILINGS MAY PERSIST AT KFAY IN THE VICINITY OF THE
FRONT AND BETTER LOW LEVEL MOISTURE.
RAIN CHANCES ARE EXPECTED TO SHIFT SOUTH OF THE AREA BY THURSDAY
WITH DRIER AIR FILTERING INTO THE AREA FROM THE NORTH. OUTSIDE OF
SOME MORNING FOG/STRATUS EACH MORNING...EXPECT PREDOMINATELY VFR
CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/SMITH
SHORT TERM...CBL/KRR
LONG TERM...KRR
AVIATION...CBL/SMITH
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
345 PM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 345 PM CDT/
CURRENTLY SEEING STRONG SOUTHERLY WINDS OUT AHEAD OF AN APPROACHING
BOUNDARY. HAD A GUST TO 45 MPH HERE AT THE AIRPORT IN SIOUX
FALLS...BUT MOST LOCATIONS ARE GUSTING CLOSER TO 30 MPH. A DECENT
700 MB WAVE IS FORECAST TO MOVE ACROSS OUR NORTHEAST TONIGHT. THIS
WILL HELP DRAG A BOUNDARY ACROSS THE AREA LATE THIS AFTERNOON INTO
THE OVERNIGHT. WINDS WILL DIMINISH AFTER SUNSET...BUT WILL TEND TO
TAKE ON AN EASTERLY COMPONENT NORTH OF THIS BOUNDARY...WHILE A
SOUTHERLY BREEZE STAYS UP SOUTH OF INTERSTATE 90. BEST LOW AND MID
LEVEL FORCING STAYS EAST OF OUR AREA...AND WITH VERY LIMITED
MOISTURE...THINK WE STAY DRY. THIS IS SUPPORTED BY THE HRRR AND NAM
WHICH KEEP ELEVATED CONVECTION TO OUR EAST TONIGHT. LOWS SHOULD DROP
INTO THE LOW AND MID 60S NORTH OF THE BOUNDARY...WITH MID AND UPPER
60S TO THE SOUTH.
MODELS HANDLE THE BOUNDARY DIFFERENTLY ON WEDNESDAY. THE NAM IS
SLOWEST TO LIFT IT NORTH...WHILE THE GFS AND ECMWF ARE A BIT
QUICKER. NAM SEEMS TO HANDLE THESE MORE MESOSCALE BOUNDARIES
BETTER...SO TRENDED A BIT TOWARDS ITS SOLUTION. THIS WOULD RESULT
IN LIGHT EASTERLY WINDS TO BEGIN THE DAY...TURING SOUTHERLY AND
INCREASING LATE IN THE DAY. TIMING OF THE BOUNDARY AND WIND INCREASE
WILL BE IMPORTANT FOR FIRE WEATHER CONCERNS. FOR NOW...WINDS ARE
EXPECTED TO STAY BELOW RED FLAG CRITERIA ACROSS THE WHOLE AREA...BUT
IT WILL BE CLOSE...AND A FASTER SOLUTION WITH THE BOUNDARY LIKE THE
ECMWF MAY PUSH THE WINDS OVER 25 MPH. HUMIDITY VALUES STILL EXPECTED
TO DROP BELOW 25 PERCENT SOUTHWEST OF A STORM LAKE TO HURON
LINE...AND INTO THE TEENS WEST OF THE JAMES RIVER. SO DUE TO THE
VERY LOW HUMIDITY AND WIND UNCERTAINTY...WILL LEAVE THE FIRE
WEATHER WATCH AS IS...AND LET THE OVERNIGHT SHIFT VIEW 0Z MODEL
TRENDS WITH REGARDS TO WINDS.
EITHER WAY...IT WILL BE HOT AND DRY WEDNESDAY WITH MOSTLY SUNNY
SKIES. FOLLOWED A BLEND OF THE BIAS CORRECTED NAM AND ECMWF
SOLUTIONS FOR HIGHS...GENERALLY GIVING 90S AND 100S ACROSS THE AREA.
WARMEST TEMPERATURES SHOULD BE NEAR THE MISSOURI RIVER WEST OF THE
JAMES RIVER. THE LACK OF A STRONG WESTERLY COMPONENT OF THE WIND
COULD ACT TO LIMIT MIXING SOMEWHAT...ALTHOUGH POSSIBLE
SUPERADIABATIC HEATING SHOULD OFFSET ANY LACK OF MIXING. EVEN WITH
THE LOW DEWPOINTS...WE MAY HIT HEAT ADVISORY CRITERIA ALONG AND
WEST OF THE JAMES RIVER. SEEMS BORDERLINE IN MOST COUNTIES...WITH
ONLY BRULE AND GREGORY BEING TO BE A GOOD BET TO HIT IT. THUS FOR
COLLABORATION PURPOSES WILL HOLD OFF ON AN ADVISORY AND LET MIDNIGHT
SHIFT TAKE ANOTHER LOOK. /CHENARD
A BROAD MID LEVEL TROUGH MOVING ALONG THE CANADIAN BORDER WILL USHER
IN STRONG SOUTHWESTERLY FLOW WEDNESDAY NIGHT INTO THE BETTER PART OF
THURSDAY. THE RESULT WILL BE WELL MIXED AND BREEZY CONDITIONS WITH
VERY WARM TEMPERATURES. AHEAD OF THE BOUNDARY ON WEDNESDAY
NIGHT...COULD SEE A FEW NOCTURNAL HIGH BASED SHOWERS AND
THUNDERSTORMS ALONG OUR WESTERN BORDER. ANY PRECIPITATION THAT DOES
DEVELOP WOULD BE VERY LIGHT AND SHOULD DISSIPATE QUICKLY BY DAYBREAK
THURSDAY. LOWS WILL BE QUITE MILD...PARTICULARLY INTO SOUTH CENTRAL
SOUTH DAKOTA WHERE STRONG MIXING AND WARM AIR ADVECTION ON THE NOSE
OF THE LOW LEVEL JET SHOULD KEEP LOWS WELL INTO THE LOWER TO MID
70S.
FRONTAL BOUNDARY BEGINS ADVANCING EASTWARD INTO THE FORECAST AREA
EARLY THURSDAY...WHICH IS SLIGHTLY FASTER TIMING THAN PREVIOUS MODEL
RUNS. MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THIS FASTER
TRACK...HOWEVER IT MAKES FOR A TRICKY TEMPERATURE FORECAST. THE WELL
MIXED CONDITIONS AHEAD OF THE FRONT WILL ALLOW FOR HIGHS FROM 100 TO
105 FOR AREAS THAT WILL SEE LONGEST MIXING...LIKELY SOUTH OF A SIOUX
FALLS TO LAKE ANDES LINE AND INTO FAR NORTHWEST IOWA. DEWPOINTS WILL
SIMILARLY PLUMMET IN THE AFTERNOON AND WILL RESULT IN MINIMUM RH
VALUES OF 15 TO 25 PERCENT FOR MUCH OF THE FORECAST AREA. WITH
ATTENDANT BREEZY WINDS...IT LOOKS LIKE ANOTHER POTENTIALLY EXTREME
FIRE WEATHER DAY. WENT AHEAD AND ISSUED A FIRE WEATHER WATCH FOR ALL
BUT THE FAR WESTERN ZONES WHICH WILL MISS OUT ON THE STRONGEST
SOUTHWEST WINDS WITH AN EARLIER FRONTAL PASSAGE.
THE EXTENDED RANGE WILL BE LARGELY DEPENDENT UPON THE TRACK OF THE
REMNANTS OF HURRICANE ISAAC. THE LATEST MODELS ARE IN SOMEWHAT
DECENT AGREEMENT WITH BRINGING THE REMNANTS NORTHWARD INTO THE
OZARKS AREA BY FRIDAY AFTERNOON. WITH UPPER LEVEL RIDGING IN PLACE
OVER THE NORTHERN PLAINS...SUBSIDENCE WILL BRING A DRY WEATHER ON
FRIDAY AND RELATIVELY LIGHT SOUTHEAST WINDS...BUT VERY LITTLE RELIEF
TO THE HEAT. HIGHS WILL REMAIN ABOVE NORMAL WITH READINGS IN THE 90S
HOWEVER HIGHER DEWPOINTS AND THE LIGHT WINDS WILL BRING SOME RELIEF
TO FIRE WEATHER CONCERNS.
MODELS BEGIN CURVING ISAAC A LITTLE MORE NORTHEASTWARD ON FRIDAY
NIGHT AND SATURDAY...WHICH BRINGS THE CENTER WHICH BRINGS THE CENTER
INTO THE MID MISSISSIPPI VALLEY. THE GFS IS SLIGHTLY WEST OF THE
ECMWF TRACK...WHILE THE GEM IS QUITE A BIT FURTHER EAST. IT STILL
LOOKS LIKE THIS SCENARIO WILL KEEP THE PRECIPITATION OUT OF OUR CWA
WITH ONLY SOME CLOUDS OR PERHAPS A STRAY SHOWER IN OUR FAR SOUTHEAST.
INTO EARLY NEXT WEEK...MODELS BEGIN DIVERGING QUITE A BIT WITH THE
POTENTIAL FOR A TROUGH MOVING INTO THE HIGH PLAINS AROUND THE
SATURDAY NIGHT THROUGH SUNDAY NIGHT TIME FRAME. THE GFS AND GEM ARE
MORE PRONOUNCED WITH THIS TROUGH WITH THE GFS BEING THE MOST
AGGRESSIVE. AT THE SAME TIME THE ECMWF WASHES OUT THE TROUGH WITH A
ZONAL FLOW PATTERN. OVERALL...NONE OF THE SOLUTIONS LOOK
PARTICULARLY IMPRESSIVE FOR PRECIPITATION CHANCES. WILL GO WITH
MENTION OF A SLIGHT CHANCE MAINLY IN OUR EAST.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
LOOKS MAINLY VFR THROUGH THE TAF PERIOD. A BOUNDARY WILL SLOWLY
SHIFT SOUTHEAST ACROSS THE AREA TODAY...WITH GUSTY SOUTHERLY WINDS
AHEAD OF IT...TURNING NORTHWESTERLY AND LIGHTER BEHIND IT. WINDS
AHEAD OF THE BOUNDARY COULD GUST AS HIGHS AS 30 MPH TODAY.
UNCERTAIN HOW FAR SOUTH THE BOUNDARY PUSHES TONIGHT BEFORE IT
RETREATS NORTHWARD. THUS WIND DIRECTION FORECAST IS UNCERTAIN FOR
THIS EVENING AND THE OVERNIGHT NEAR KFSD...BUT SPEEDS SHOULD
GENERALLY BE UNDER 10 KTS. ON WEDNESDAY WINDS WILL INITIALLY HAVE AN
EASTERLY COMPONENT...BEFORE TURNING MORE SOUTHERLY AND INCREASING
THROUGH THE DAY. SOME PATCHY FOG IS POSSIBLE TONIGHT NORTH OF THE
BOUNDARY AS LOW LEVEL MOISTURE POOLS. THUS KEPT A MENTION IN THE
KHON TAF FOR MVFR VISIBILITY...FEEL THERE IS TOO MUCH UNCERTAINTY ON
POSITION OF THE BOUNDARY TO INCLUDE ANY RESTRICTIONS IN THE KFSD TAF
AT THIS TIME. /CHENARD
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR IAZ300-301.
MN...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR MNZ900.
NE...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR NEZ249.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ249.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR NEZ249.
SD...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR SDZ258.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR SDZ255-258.
FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR SDZ257-258.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1225 PM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 1102 AM CDT/
ELEVATED CONVECTION PUSHING EAST OF OUR AREA. OUTFLOW FROM THIS
ACTIVITY HAS A BUSHED A WEAK BOUNDARY SOUTH INTO AREA NORTH OF
INTERSTATE 90...GIVING WINDS THERE MORE OF AN EASTERLY COMPONENT AND
SLOWING HEATING SOME. FEEL THAT THIS BOUNDARY WILL WASH OUT WITH
WINDS TURNING MORE SOUTHERLY BY THIS AFTERNOON. MEANWHILE EXPECTING
A WEAK AREA OF LOW PRESSURE TO BE JUST WEST OF OUR CWA AT 18Z. THIS
FEATURE AND ASSOCIATED FRONT WILL PUSH EAST THROUGH THE
AFTERNOON...TURNING WINDS WESTERLY WEST OF THE JAMES RIVER AND
EVENTUALLY AS FAR EAST AS SIOUX FALLS BY 0Z. UNFORTUNATELY NO COOLER
AIR IS FOUND BEHIND THIS BOUNDARY...SO GOING HIGH TEMPERATURES LOOK
TO BE IN PRETTY GOOD SHAPE. STILL SEEING SOME ACCAS CLOUDS PUSHING
EAST WHICH MAY LIMIT FULL HEATING IN SOME AREAS. IF THESE ARE ABLE
TO COMPLETELY DISSIPATE...HIGHS MAY BE A BIT WARMER THAN CURRENT
FORECAST DEPICTS FOR THIS AFTERNOON. SHOULD BE A MAINLY DRY REST OF
THE DAY...OUTSIDE OF A VERY ISOLATED SHOWER OUT OF THE ACCAS. THE
RED FLAG WARNING LOOKS GOOD AT THIS POINT. SOUTHWESTERLY WINDS ARE
EXPECTED TO GUST AROUND 30 MPH IN THE WARNED AREA...WITH HUMIDITY
LEVELS DROPPING TO AROUND 25 PERCENT AS MIXING MAXIMIZES THIS
AFTERNOON. /CHENARD
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
LOOKS MAINLY VFR THROUGH THE TAF PERIOD. A BOUNDARY WILL SLOWLY
SHIFT SOUTHEAST ACROSS THE AREA TODAY...WITH GUSTY SOUTHERLY WINDS
AHEAD OF IT...TURNING NORTHWESTERLY AND LIGHTER BEHIND IT. WINDS
AHEAD OF THE BOUNDARY COULD GUST AS HIGHS AS 30 MPH TODAY.
UNCERTAIN HOW FAR SOUTH THE BOUNDARY PUSHES TONIGHT BEFORE IT
RETREATS NORTHWARD. THUS WIND DIRECTION FORECAST IS UNCERTAIN FOR
THIS EVENING AND THE OVERNIGHT NEAR KFSD...BUT SPEEDS SHOULD
GENERALLY BE UNDER 10 KTS. ON WEDNESDAY WINDS WILL INITIALLY HAVE AN
EASTERLY COMPONENT...BEFORE TURNING MORE SOUTHERLY AND INCREASING
THROUGH THE DAY. SOME PATCHY FOG IS POSSIBLE TONIGHT NORTH OF THE
BOUNDARY AS LOW LEVEL MOISTURE POOLS. THUS KEPT A MENTION IN THE
KHON TAF FOR MVFR VISIBILITY...FEEL THERE IS TOO MUCH UNCERTAINTY ON
POSITION OF THE BOUNDARY TO INCLUDE ANY RESTRICTIONS IN THE KFSD TAF
AT THIS TIME. /CHENARD
&&
.PREVIOUS DISCUSSION.../ISSUED AT 459 AM CDT/
FIRE WEATHER CONCERNS AT THE FOREFRONT TODAY...THOUGH IN THE
IMMEDIATE TERM WATCHING SOME ELEVATED THUNDERSTORMS WORK THEIR WAY
INTO NORTHWEST PARTS OF THE CWA. GREATER COVERAGE/INTENSITY STORMS
EXPECTED TO REMAIN NORTH AND NORTHEAST OF OUR FORECAST AREA IN AREA
OF STRONG MID LEVEL THETA-E ADVECTION WHICH IS PROGGED TO EXTEND
FROM FAR NORTHEAST SD/FAR SOUTHEAST ND INTO CENTRAL/SOUTHEAST MN
THIS MORNING. THAT SAID...WEAKER EXTENSION OF THETA-E ADVECTION
AHEAD OF COMPACT MID LEVEL WAVE WILL MOVE ACROSS OUR FORECAST AREA
THIS MORNING AND WILL TRACK 20-30 PERCENT POPS EASTWARD THROUGH 18Z.
DO NOT EXPECT MUCH RAINFALL TO REACH THE GROUND WITH THESE STORMS AS
SUB CLOUD LAYER IS QUITE DRY. HOWEVER...LIGHTNING THREAT IS THERE
AND AS SUCH FEEL ISOLATED MENTION IS WARRANTED.
TEMPERATURES TRICKIEST PART OF THE NEXT FEW DAYS...AS MODELS STILL
WILDLY DIVERGENT IN THEIR LOW LEVEL TEMPERATURE/MOISTURE PROFILES.
HOWEVER WARMER/DRIER NAM...ALTHOUGH IT SEEMS OVERLY MIXED AND WAY
TOO WARM IN ITS 2 METER TEMPERATURE FORECAST...HAS BETTER SUPPORT
FROM ECMWF/GEM IN 850/925MB TEMPERATURES...AND THUS HEDGING TOWARD
WARMER SIDE OF FORECAST TEMPERATURE GUIDANCE SEEMS THE WAY TO GO IN
THIS PATTERN. WITH THIS...HAVE NUDGED TEMPERATURES UP A LITTLE MORE
FROM PREVIOUS FORECAST FOR WEDNESDAY/THURSDAY. FORTUNATELY HUMIDITY
LEVELS EXPECTED TO REMAIN IN CHECK...AS DEEP MIXING NEEDED TO
ACHIEVE THE HOT TEMPERATURES WILL ALSO MIX DOWN DRIER AIR. WHILE
THIS IS GOOD NEWS AS FAR AS LIMITING NEED FOR HEAT ADVISORIES...IT
DOES PRODUCE SIGNIFICANT FIRE WEATHER CONCERNS AS ALLUDED TO ABOVE.
THIS IS DISCUSSED IN MUCH GREATER DETAIL IN FIRE WEATHER SECTION
OF THIS PRODUCT. HOWEVER...IN SHORT...GUSTY SOUTH WINDS AND LOW
AFTERNOON HUMIDITY LEVELS HAVE PROMPTED ISSUANCE OF RED FLAG WARNING
FOR THE LOWER JAMES/BIG SIOUX VALLEYS AND EXTREME NORTHEAST NEBRASKA
THIS AFTERNOON. FIRE WEATHER WATCH ALSO ISSUED FOR THESE AREAS...
ALONG WITH THE LOWER BRULE AREA IN SOUTH CENTRAL SD...FOR WEDNESDAY
AFTERNOON/EARLY EVENING. ALTHOUGH NO HEADLINES HAVE YET BEEN ISSUED
FOR THURSDAY...EXPANSION OF VERY HIGH/EXTREME FIRE DANGER AND
POTENTIAL RED FLAG CONDITIONS IS EXPECTED AND WILL WATCH THIS PERIOD
CLOSELY FOR HEADLINES OVER THE NEXT 12-24 HOURS.
LONGER RANGE SEES REMNANTS OF ISAAC PROGGED TO LIFT NORTH THROUGH
THE NATIONS MIDSECTION FRIDAY/SATURDAY...THEN TURNING EASTWARD BUT
LINGERING OVER THE WESTERN OHIO VALLEY INTO SUNDAY/MONDAY. WILL NOT
SEE ANY RAIN IN THIS AREA FROM THE ISAAC REMNANTS. HOWEVER...WILL
HAVE AN EFFECT IN SLOWING ANY POTENTIAL SOUTHEASTWARD PUSH OF COOL
FRONT WHICH IS FORECAST TO MOVE INTO OUR AREA LATE IN THIS FORECAST
PERIOD. THIS WILL RESULT IN PERSISTENCE OF WELL ABOVE NORMAL
TEMPERATURES RIGHT THROUGH THE LABOR DAY HOLIDAY. FRIDAY/SATURDAY
SHOULD BE WARMEST DAYS OF THE LONGER RANGE...THOUGH SHOULD BE COOLER
THAN MIDWEEK AS THERMAL RIDGE BREAKS TOWN AS THE THURSDAY/THURSDAY
NIGHT FRONT WASHES OUT. THUS HAVE TEMPERED HIGHS INTO THE UPPER 80S
TO MID 90S...WITH COOLEST READINGS LIKELY TO BE IN SOUTHEAST CWA ON
SATURDAY AS FLOW BEGINS TO PULL A LITTLE COOLER AIR OUT OF ISAAC
REMNANTS AS THEY MOVE INTO MISSOURI/SOUTHEAST IOWA. WITH NEXT COOL
FRONT SET TO MOVE IN SUNDAY/MONDAY TIME FRAME...COULD SEE POTENTIAL
FOR SHOWERS/THUNDERSTORMS SOME DURING THIS PERIOD. HOWEVER...OPTED
TO KEEP THE PERIOD DRY FOR NOW UNTIL MODELS GET A BETTER HANDLE ON
REMNANTS OF ISAAC AND EFFECT OF THAT ON FRONTAL TIMING.
&&
.FIRE WEATHER...
SUBTLE LOW LEVEL BOUNDARY TRAILING SOUTHWESTWARD FROM THE MID LEVEL
WAVE WILL DRIFT TOWARD WESTERN EDGE OF THE CWA THIS AFTERNOON. THIS
WILL LIMIT FIRE DANGER FOR THE MIDDLE JAMES/LOWER BRULE AREAS TODAY.
HOWEVER...LOW RELATIVE HUMIDITY LEVELS WILL STILL CREATE HIGH TO
VERY HIGH DANGER IN THESE AREAS. GREATER CONCERN FOR TODAY IS FROM
THE LOWER JAMES/LOWER BIG SIOUX VALLEY AREAS INTO EXTREME NORTHEAST
NEBRASKA. THIS FAR ENOUGH REMOVED FROM THE BOUNDARY THAT SOUTHERLY
GUSTS IN EXCESS OF 25 MPH ARE LIKELY WITH MIXING THIS AFTERNOON. THE
DEEP MIXING EXPECTED TO BRING DOWN SOME OF THE DRIER AIR EVIDENT ON
THE 28/00Z LBF RAOB LAST EVENING. NAM AND TO SOME EXTENT HRRR SEEM
TO CAPTURE THIS IDEA BEST AND HAVE LEANED CLOSER TO THESE MODELS FOR
DROPPING DEW POINTS WITH AFTERNOON MIXING. THIS RESULTS IN MINIMUM
HUMIDITY LEVELS OF 20-25 PERCENT IN THE CONCERN AREA THIS AFTERNOON
AND HAVE ISSUED A RED FLAG WARNING FOR THESE TWO FIRE WEATHER ZONES
TODAY.
WEDNESDAY A LITTLE MORE UNCERTAIN...AS THAT WEAK BOUNDARY FORECAST
TO PUSH INTO THE SOUTHERN CWA TONIGHT BEFORE STALLING AND LIFTING
SLOWLY BACK TO THE NORTH ON WEDNESDAY. QUESTION WILL BE WHETHER IT
WILL SHIFTS NORTH EARLY ENOUGH TO ALLOW STRONGER SOUTH WINDS TO MIX
DOWN THROUGH THE MISSOURI RIVER VALLEY AREAS. RELATIVE HUMIDITY FROM
SOUTH CENTRAL SD...THROUGH THE MISSOURI VALLEY INTO THE SIOUX CITY
AREA CERTAINLY WORTHY OF HEIGHTENED FIRE WATCH...AS ALL MODELS
EXCEPT GFS INDICATE AFTERNOON DEW POINTS MIXING DOWN INTO THE 40S...
RESULTING IN MINIMUM HUMIDITY VALUES BELOW 20 PERCENT. GIVEN LOWER
CONFIDENCE IN WEDNESDAY AFTERNOON WIND FORECAST...NOT COMFORTABLE
WITH A DAY 2 RED FLAG WARNING JUST YET. HOWEVER HAVE ISSUED A FIRE
WEATHER WATCH FOR THE AREAS OF CONCERN.
DESPITE ALL OF THE ABOVE...THURSDAY PRESENTS GREATEST FIRE WEATHER
CONCERN AT THIS POINT. NORTHERN STREAM WAVE TOPPING THE BROAD UPPER
RIDGE WILL DRAG A COOL FRONT INTO THE NORTHWEST 1/3 OF THE CWA BY
THURSDAY AFTERNOON. DEEP SOUTHWEST FLOW WITHIN LOW LEVEL JET AHEAD
OF THIS BOUNDARY WILL ALLOW FOR WIDESPREAD 20-25 MPH SUSTAINED WINDS
WITH GUSTS OF 30-35 MPH LIKELY OVER MUCH OF THE CWA. THIS ALONG WITH
STRONG THERMAL RIDGE AHEAD OF BOUNDARY COULD RESULT IN NEAR RECORD
HIGHS AROUND 100 DEGREES...AND DEW POINTS MIXING INTO THE 40S...WILL
AGAIN PRODUCE MINIMUM HUMIDITY VALUES BELOW 20 PERCENT IN SOUTHWEST
TO NORTHEAST CORRIDOR THROUGH THE CENTER OF THE CWA...LAKE ANDES AND
YANKTON...THROUGH SIOUX FALLS...INTO SOUTHWEST MN. GIVEN THE MORE
IMMEDIATE FIRE DANGER THE NEXT COUPLE OF DAYS...HAVE HELD OFF
ISSUING ANY HEADLINE FOR THURSDAY JUST YET...BUT WILL CERTAINLY
HIGHLIGHT VERY HIGH TO EXTREME FIRE DANGER IN THE HAZARDOUS WEATHER
OUTLOOK AND DAY SHIFT WILL WANT TO COORDINATE POTENTIAL HEADLINES
WITH AFFECTED FIRE OFFICIALS FOR POSSIBLE ISSUANCE THIS AFTERNOON OR
WEDNESDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR NEZ249.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ249.
SD...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR SDZ258.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR SDZ255-258.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1102 AM CDT TUE AUG 28 2012
.DISCUSSION.../ISSUED AT 1102 AM CDT/
ELEVATED CONVECTION PUSHING EAST OF OUR AREA. OUTFLOW FROM THIS
ACTIVITY HAS A BUSHED A WEAK BOUNDARY SOUTH INTO AREA NORTH OF
INTERSTATE 90...GIVING WINDS THERE MORE OF AN EASTERLY COMPONENT AND
SLOWING HEATING SOME. FEEL THAT THIS BOUNDARY WILL WASH OUT WITH
WINDS TURNING MORE SOUTHERLY BY THIS AFTERNOON. MEANWHILE EXPECTING
A WEAK AREA OF LOW PRESSURE TO BE JUST WEST OF OUR CWA AT 18Z. THIS
FEATURE AND ASSOCIATED FRONT WILL PUSH EAST THROUGH THE
AFTERNOON...TURNING WINDS WESTERLY WEST OF THE JAMES RIVER AND
EVENTUALLY AS FAR EAST AS SIOUX FALLS BY 0Z. UNFORTUNATELY NO COOLER
AIR IS FOUND BEHIND THIS BOUNDARY...SO GOING HIGH TEMPERATURES LOOK
TO BE IN PRETTY GOOD SHAPE. STILL SEEING SOME ACCAS CLOUDS PUSHING
EAST WHICH MAY LIMIT FULL HEATING IN SOME AREAS. IF THESE ARE ABLE
TO COMPLETELY DISSIPATE...HIGHS MAY BE A BIT WARMER THAN CURRENT
FORECAST DEPICTS FOR THIS AFTERNOON. SHOULD BE A MAINLY DRY REST OF
THE DAY...OUTSIDE OF A VERY ISOLATED SHOWER OUT OF THE ACCAS. THE
RED FLAG WARNING LOOKS GOOD AT THIS POINT. SOUTHWESTERLY WINDS ARE
EXPECTED TO GUST AROUND 30 MPH IN THE WARNED AREA...WITH HUMIDITY
LEVELS DROPPING TO AROUND 25 PERCENT AS MIXING MAXIMIZES THIS
AFTERNOON. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 459 AM CDT/
FIRE WEATHER CONCERNS AT THE FOREFRONT TODAY...THOUGH IN THE
IMMEDIATE TERM WATCHING SOME ELEVATED THUNDERSTORMS WORK THEIR WAY
INTO NORTHWEST PARTS OF THE CWA. GREATER COVERAGE/INTENSITY STORMS
EXPECTED TO REMAIN NORTH AND NORTHEAST OF OUR FORECAST AREA IN AREA
OF STRONG MID LEVEL THETA-E ADVECTION WHICH IS PROGGED TO EXTEND
FROM FAR NORTHEAST SD/FAR SOUTHEAST ND INTO CENTRAL/SOUTHEAST MN
THIS MORNING. THAT SAID...WEAKER EXTENSION OF THETA-E ADVECTION
AHEAD OF COMPACT MID LEVEL WAVE WILL MOVE ACROSS OUR FORECAST AREA
THIS MORNING AND WILL TRACK 20-30 PERCENT POPS EASTWARD THROUGH 18Z.
DO NOT EXPECT MUCH RAINFALL TO REACH THE GROUND WITH THESE STORMS AS
SUB CLOUD LAYER IS QUITE DRY. HOWEVER...LIGHTNING THREAT IS THERE
AND AS SUCH FEEL ISOLATED MENTION IS WARRANTED.
TEMPERATURES TRICKIEST PART OF THE NEXT FEW DAYS...AS MODELS STILL
WILDLY DIVERGENT IN THEIR LOW LEVEL TEMPERATURE/MOISTURE PROFILES.
HOWEVER WARMER/DRIER NAM...ALTHOUGH IT SEEMS OVERLY MIXED AND WAY
TOO WARM IN ITS 2 METER TEMPERATURE FORECAST...HAS BETTER SUPPORT
FROM ECMWF/GEM IN 850/925MB TEMPERATURES...AND THUS HEDGING TOWARD
WARMER SIDE OF FORECAST TEMPERATURE GUIDANCE SEEMS THE WAY TO GO IN
THIS PATTERN. WITH THIS...HAVE NUDGED TEMPERATURES UP A LITTLE MORE
FROM PREVIOUS FORECAST FOR WEDNESDAY/THURSDAY. FORTUNATELY HUMIDITY
LEVELS EXPECTED TO REMAIN IN CHECK...AS DEEP MIXING NEEDED TO
ACHIEVE THE HOT TEMPERATURES WILL ALSO MIX DOWN DRIER AIR. WHILE
THIS IS GOOD NEWS AS FAR AS LIMITING NEED FOR HEAT ADVISORIES...IT
DOES PRODUCE SIGNIFICANT FIRE WEATHER CONCERNS AS ALLUDED TO ABOVE.
THIS IS DISCUSSED IN MUCH GREATER DETAIL IN FIRE WEATHER SECTION
OF THIS PRODUCT. HOWEVER...IN SHORT...GUSTY SOUTH WINDS AND LOW
AFTERNOON HUMIDITY LEVELS HAVE PROMPTED ISSUANCE OF RED FLAG WARNING
FOR THE LOWER JAMES/BIG SIOUX VALLEYS AND EXTREME NORTHEAST NEBRASKA
THIS AFTERNOON. FIRE WEATHER WATCH ALSO ISSUED FOR THESE AREAS...
ALONG WITH THE LOWER BRULE AREA IN SOUTH CENTRAL SD...FOR WEDNESDAY
AFTERNOON/EARLY EVENING. ALTHOUGH NO HEADLINES HAVE YET BEEN ISSUED
FOR THURSDAY...EXPANSION OF VERY HIGH/EXTREME FIRE DANGER AND
POTENTIAL RED FLAG CONDITIONS IS EXPECTED AND WILL WATCH THIS PERIOD
CLOSELY FOR HEADLINES OVER THE NEXT 12-24 HOURS.
LONGER RANGE SEES REMNANTS OF ISAAC PROGGED TO LIFT NORTH THROUGH
THE NATIONS MIDSECTION FRIDAY/SATURDAY...THEN TURNING EASTWARD BUT
LINGERING OVER THE WESTERN OHIO VALLEY INTO SUNDAY/MONDAY. WILL NOT
SEE ANY RAIN IN THIS AREA FROM THE ISAAC REMNANTS. HOWEVER...WILL
HAVE AN EFFECT IN SLOWING ANY POTENTIAL SOUTHEASTWARD PUSH OF COOL
FRONT WHICH IS FORECAST TO MOVE INTO OUR AREA LATE IN THIS FORECAST
PERIOD. THIS WILL RESULT IN PERSISTENCE OF WELL ABOVE NORMAL
TEMPERATURES RIGHT THROUGH THE LABOR DAY HOLIDAY. FRIDAY/SATURDAY
SHOULD BE WARMEST DAYS OF THE LONGER RANGE...THOUGH SHOULD BE COOLER
THAN MIDWEEK AS THERMAL RIDGE BREAKS TOWN AS THE THURSDAY/THURSDAY
NIGHT FRONT WASHES OUT. THUS HAVE TEMPERED HIGHS INTO THE UPPER 80S
TO MID 90S...WITH COOLEST READINGS LIKELY TO BE IN SOUTHEAST CWA ON
SATURDAY AS FLOW BEGINS TO PULL A LITTLE COOLER AIR OUT OF ISAAC
REMNANTS AS THEY MOVE INTO MISSOURI/SOUTHEAST IOWA. WITH NEXT COOL
FRONT SET TO MOVE IN SUNDAY/MONDAY TIME FRAME...COULD SEE POTENTIAL
FOR SHOWERS/THUNDERSTORMS SOME DURING THIS PERIOD. HOWEVER...OPTED
TO KEEP THE PERIOD DRY FOR NOW UNTIL MODELS GET A BETTER HANDLE ON
REMNANTS OF ISAAC AND EFFECT OF THAT ON FRONTAL TIMING.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
THE ENTIRE FORECAST PERIOD THROUGH 12Z WEDNESDAY SHOULD BE
REPRESENTED WELL BY VFR CONDITIONS. ISOLATED HIGH BASED LIGHT
SHOWERS WITH PERHAPS A RUMBLE OF THUNDER WILL SLIDE THROUGH AREAS
NORTH OF INTERSTATE 90 EARLY THIS MORNING...BUT EVEN THE HEAVIEST
SHOWER OR STORM WOULD LIKELY REMAIN ABOVE VFR THRESHOLDS. THE
PROBABILITY OF THUNDER IS SUCH THAT WILL NOT MENTION IN TAF FOR KFSD
OR KHON...BUT THERE WILL BE ISOLATED STORMS AROUND THE AREA THROUGH
AT LEAST MID MORNING. AS WEAK FRONT ACROSS CENTRAL SOUTH DAKOTA
SAGS SOUTHWARD AND STALLS LATER TONIGHT NEAR KFSD...MAY FIND ENOUGH
WEAK CONVERGENCE TO POOL MOISTURE NEAR AND POST FRONTAL...FOR SOME
SPOTTY MVFR VISIBILITIES STARTING AROUND 09Z. /CHAPMAN
&&
.FIRE WEATHER...
SUBTLE LOW LEVEL BOUNDARY TRAILING SOUTHWESTWARD FROM THE MID LEVEL
WAVE WILL DRIFT TOWARD WESTERN EDGE OF THE CWA THIS AFTERNOON. THIS
WILL LIMIT FIRE DANGER FOR THE MIDDLE JAMES/LOWER BRULE AREAS TODAY.
HOWEVER...LOW RELATIVE HUMIDITY LEVELS WILL STILL CREATE HIGH TO
VERY HIGH DANGER IN THESE AREAS. GREATER CONCERN FOR TODAY IS FROM
THE LOWER JAMES/LOWER BIG SIOUX VALLEY AREAS INTO EXTREME NORTHEAST
NEBRASKA. THIS FAR ENOUGH REMOVED FROM THE BOUNDARY THAT SOUTHERLY
GUSTS IN EXCESS OF 25 MPH ARE LIKELY WITH MIXING THIS AFTERNOON. THE
DEEP MIXING EXPECTED TO BRING DOWN SOME OF THE DRIER AIR EVIDENT ON
THE 28/00Z LBF RAOB LAST EVENING. NAM AND TO SOME EXTENT HRRR SEEM
TO CAPTURE THIS IDEA BEST AND HAVE LEANED CLOSER TO THESE MODELS FOR
DROPPING DEW POINTS WITH AFTERNOON MIXING. THIS RESULTS IN MINIMUM
HUMIDITY LEVELS OF 20-25 PERCENT IN THE CONCERN AREA THIS AFTERNOON
AND HAVE ISSUED A RED FLAG WARNING FOR THESE TWO FIRE WEATHER ZONES
TODAY.
WEDNESDAY A LITTLE MORE UNCERTAIN...AS THAT WEAK BOUNDARY FORECAST
TO PUSH INTO THE SOUTHERN CWA TONIGHT BEFORE STALLING AND LIFTING
SLOWLY BACK TO THE NORTH ON WEDNESDAY. QUESTION WILL BE WHETHER IT
WILL SHIFTS NORTH EARLY ENOUGH TO ALLOW STRONGER SOUTH WINDS TO MIX
DOWN THROUGH THE MISSOURI RIVER VALLEY AREAS. RELATIVE HUMIDITY FROM
SOUTH CENTRAL SD...THROUGH THE MISSOURI VALLEY INTO THE SIOUX CITY
AREA CERTAINLY WORTHY OF HEIGHTENED FIRE WATCH...AS ALL MODELS
EXCEPT GFS INDICATE AFTERNOON DEW POINTS MIXING DOWN INTO THE 40S...
RESULTING IN MINIMUM HUMIDITY VALUES BELOW 20 PERCENT. GIVEN LOWER
CONFIDENCE IN WEDNESDAY AFTERNOON WIND FORECAST...NOT COMFORTABLE
WITH A DAY 2 RED FLAG WARNING JUST YET. HOWEVER HAVE ISSUED A FIRE
WEATHER WATCH FOR THE AREAS OF CONCERN.
DESPITE ALL OF THE ABOVE...THURSDAY PRESENTS GREATEST FIRE WEATHER
CONCERN AT THIS POINT. NORTHERN STREAM WAVE TOPPING THE BROAD UPPER
RIDGE WILL DRAG A COOL FRONT INTO THE NORTHWEST 1/3 OF THE CWA BY
THURSDAY AFTERNOON. DEEP SOUTHWEST FLOW WITHIN LOW LEVEL JET AHEAD
OF THIS BOUNDARY WILL ALLOW FOR WIDESPREAD 20-25 MPH SUSTAINED WINDS
WITH GUSTS OF 30-35 MPH LIKELY OVER MUCH OF THE CWA. THIS ALONG WITH
STRONG THERMAL RIDGE AHEAD OF BOUNDARY COULD RESULT IN NEAR RECORD
HIGHS AROUND 100 DEGREES...AND DEW POINTS MIXING INTO THE 40S...WILL
AGAIN PRODUCE MINIMUM HUMIDITY VALUES BELOW 20 PERCENT IN SOUTHWEST
TO NORTHEAST CORRIDOR THROUGH THE CENTER OF THE CWA...LAKE ANDES AND
YANKTON...THROUGH SIOUX FALLS...INTO SOUTHWEST MN. GIVEN THE MORE
IMMEDIATE FIRE DANGER THE NEXT COUPLE OF DAYS...HAVE HELD OFF
ISSUING ANY HEADLINE FOR THURSDAY JUST YET...BUT WILL CERTAINLY
HIGHLIGHT VERY HIGH TO EXTREME FIRE DANGER IN THE HAZARDOUS WEATHER
OUTLOOK AND DAY SHIFT WILL WANT TO COORDINATE POTENTIAL HEADLINES
WITH AFFECTED FIRE OFFICIALS FOR POSSIBLE ISSUANCE THIS AFTERNOON OR
WEDNESDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR NEZ249.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR NEZ249.
SD...RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 8 PM THIS EVENING
FOR SDZ258.
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR SDZ255-258.
&&
$$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
155 PM CDT TUE AUG 28 2012
.SHORT TERM.../TONIGHT THROUGH WEDNESDAY NIGHT/...A PACIFIC LOW OFF
THE NW US COAST MOVES INLAND WHILE THE MID LEVEL RIDGE CENTERED OVER
COLORADO BEGINS TO EDGE EASTWARD TOWARDS THE CENTRAL PLAINS. THE
RIDGE...SQUEEZED BETWEEN THE PACIFIC LOW AND LAND-FALLING ISAAC
BEGINS TO FLATTEN AND ELONGATE AS IT MOVES EAST. THE BIG STORY IN
THE SHORT TERM PERIOD REMAINS RECENTLY UPGRADED HURRICANE ISAAC. THE
LATEST NHC FORECAST HAS ISAAC MAKING LANDFALL ALONG THE SOUTHEASTERN
LOUISIANA COAST LATER THIS EVENING.
MEANWHILE THE RGV AND DEEP SOUTH TEXAS IS CAUGHT BETWEEN THE RIDGE
AND ISSAC...WHILE THE NORTHERN REACHES OF AN UPPER LEVEL
LOW...CENTERED OVER NORTHEAST MEXICO...MOVES WEST ACROSS THE LOWER
RGV. ISOLATED SHOWERS ASSOCIATED WITH A WEAK SHORTWAVE MOVING
SOUTH...HAVE STARTED TO MOVE INTO THE CWA FROM THE NORTH AND WILL
DISSIPATE BY TONIGHT. LIGHT AND VARIABLE WINDS CAN BE EXPECTED
OVERNIGHT WITH HIGH CIRRUS FROM ISAAC COVERING PORTIONS OF THE SKY.
WEDNESDAY...CIRRUS CLOUDS WILL PERSIST THROUGH THE PERIOD BUT SHOULD
NOT IMPACT TEMPERATURES TOO MUCH. AFTERNOON HIGHS WILL REMAIN TOASTY
ACROSS THE REGION WITH MANY LOCALES SEEING HIGHS NEAR OR ABOVE THE
CENTURY MARK. NORTHERLY FLOW WILL ALLOW DRIER AIR TO BEGIN TO FILTER
INTO THE REGION LATE IN THE PERIOD. MAINTAINED INHERITED POPS AS I
BELIEVE LATEST MODEL RUNS TO BE TOO GENEROUS WITH THE PRECIP.
.LONG TERM.../THURSDAY THROUGH TUESDAY/...
BY THURSDAY HURRICANE ISAAC CENTER WILL BE LOCATED OVER THE NORTHERN
LOUISIANA WITH THE LATEST FORECAST FROM THE NHC. THIS SYSTEM IS
EXPECTED TO MOVE NORTH/NORTHWEST SPLITTING IN HALF THE UPPER HIGH
ACROSS THE CENTRAL PLAINS. DRY AIR ALOFT RAP AROUND THIS SYSTEM WILL
INFILTRATE INTO SOUTH TEXAS WITH A NORTHERLY FLOW. MINIMUM RH VALUES
WILL FALL BELOW 20 PERCENT ESPECIALLY ACROSS THE NORTHWEST PORTION
OF THE VALLEY THURSDAY. HOWEVER...LIGHT TO BREEZE SE WINDS WILL
LIMIT CRITICAL FIRE WEATHER CONDITIONS TO OCCUR. QUICKLY INTO
FRIDAY...SOUTHEAST FLOW RETURNS GRADUALLY ADVECTING LOW LEVEL
MOISTURE INTO THE CWA. A FEW ISOLATED SHOWERS CAN NOT BE RULED OUT
FROM CONVECTION DEBRI CLOUDS STREAMING ACROSS THE LOWER VALLEY
THROUGH THE REMAINDER OF THE WEEK. SUBSIDENCE WILL ALLOW FOR HIGH
TEMPERATURES TO REMAIN UP TO 5 DEGREES ABOVE NORMAL ACROSS THE CWA
WITH A FEW LOCALES IN THE WEST EVEN HIGHER. FRIDAY SE WINDS INCREASE
A BIT IN THE AFTERNOON TO MORE BREEZE TO WINDY CONDITIONS AS SURFACE
HIGH STRENGTHENS RIGHT OVER THE GULF.
FOR THE WEEKEND...BEST POSSIBILITY OF SEA BREEZE CONVECTION TO OCCUR
WILL LIKELY BE SATURDAY AND SUNDAY AFTERNOON AS MORE ABUNDANT
MOISTURE MOVES ALONG THE COASTAL COUNTIES. LEFT INHERITED 20 PERCENT
POPS FOR SATURDAY AND SUNDAY AS THIS SHOWERS MAY INCREASE AND MOVE
WESTWARD. TEMPERATURES WILL BE NEAR NORMAL FOR THE WEEKEND AS CLOUD
COVER AND RAINFALL BRING A SMALL BREAK TO THE TRIPLE DIGITS BY
COAST. LOWS WILL REMAIN IN THE UPPER 70S ACROSS THE VALLEY AND
DROPPING A FEW DEGREES SATURDAY NIGHT ESPECIALLY NORTHERN PORTION OF
THE CWA.
&&
.MARINE...TONIGHT THROUGH WEDNESDAY NIGHT...BUOY 42020 REPORTED
NORTHWEST WINDS AROUND 12 KNOTS WITH SEAS AT 3.6 FEET EARLY THIS
AFTERNOON. SEAS WILL GRADUALLY BUILD THIS EVENING THROUGH EARLY
WEDNESDAY AS LARGE SWELLS FROM HURRICANE ISAAC APPROACH FROM THE
EAST. SEAS MAY APPROACH SMALL CRAFT ADVISORY CONDITIONS DURING THE
OVERNIGHT HOURS TONIGHT. AS ISAAC MOVES INLAND AND SWELLS WILL
DECREASE SEAS WILL BEGIN TO SUBSIDE BY WEDNESDAY AFTERNOON.
THURSDAY THROUGH MONDAY...
SEAS WILL BE BETWEEN 3 TO 5 FEET FROM THURSDAY THROUGH SATURDAY AS
THE LARGE SCALE WIND FLOW OVER THE GULF IS DOMINATED BY HURRICANE
ISAAC AND IT CONTINUES TO INCREASE SWELLS OVER THE GULF. A FEW
SHOWERS AND THUNDERSTORMS ARE LIKELY OVER THE OFFSHORE WATERS. NW
FLOW SHIFTS TO THE SE AS HIGH PRESSURE OVER THE GULF TRIES TO
BUILD. EXPECT SE WINDS TO PICK UP FRIDAY AFTERNOON WITH A TIGHTER
GRADIENT ALONG THE COASTAL WATERS. BY SUNDAY CONDITIONS SHOULD
BEGIN TO IMPROVE WITH LOWER SEAS BETWEEN 2 TO 3 FEET NEAR AND
OFFSHORE.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 78 95 77 91 / 10 10 0 10
BROWNSVILLE 77 98 76 100 / 10 10 0 10
HARLINGEN 76 100 74 101 / 10 10 0 10
MCALLEN 79 101 77 103 / 20 10 0 10
RIO GRANDE CITY 78 101 78 105 / 20 10 0 10
SOUTH PADRE ISLAND 79 91 78 90 / 10 10 0 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK THROUGH WEDNESDAY MORNING FOR TXZ251-256-
257.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
58/67
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1244 PM CDT TUE AUG 28 2012
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...RISK OF ELEVATED CONVECTION WORKING INTO THE WRN PART OF
THE FCST AREA HAS INCREASED. LATEST RAP SEEMS TO HAVE THE BEST
HANDLE ON THE SITN. UPDATED THE FCST TO INCLUDED CHC POPS ACRS THE
NW 1/3 FOR THE AFTN INTO TNGT. WL RE-EVALUATE FOR THE MAIN ISSUANCE.
SKOWRONSKI
&&
PREV DISCUSSION...ISSUED AT 332 AM CDT TUE AUG 28 2012...
TODAY...FORECAST CONFIDENCE - MEDIUM TO HIGH.
WEAK FORCING ASSOCIATED WITH MID-LEVEL WAVE CONTRIBUTING TO
EXPANDING MID CLOUDS OVER EAST CENTRAL WI EARLY THIS MRNG. CLOUDS
SPREADING SOUTHEAST ALONG WITH WEAK FORCING SO NOT EXPECTING MUCH
MID-LEVEL CLOUDS TO HANG ON ACROSS EASTERN SECTION BEYOND 12-14Z.
WEAK LOW LEVEL CONVERGENCE MAY TRIGGER BRIEF PERIOD OF FEW-SCT LOW
CLOUDS NEAR LAKE MICHIGAN DUE TO LINGERING MOIST MARINE LAYER AND
WINDS SHIFTING TO THE NORTHEAST.
OTHERWISE EXPECT A GENERAL INCREASE IN MID-HIGH LEVEL CLOUDS THROUGH
THE DAY DUE TO UPSTREAM WARM AIR ADVECTION SPREADING INTO
MN/IA...ESPECIALLY IN WESTERN CWA. LAKE BREEZE EXPECTED TO KEEP
LAKESHORE AREAS 5 TO 10 DEGREES COOLER...WHILE AREAS WELL INLAND
SHOULD CLIMB TO LEVELS SIMILAR TO YESTERDAY.
TONIGHT...FORECAST CONFIDENCE - MEDIUM.
UPSTREAM WARM AIR ADVECTION TRIGGERING INCREASING CONVECTION ACROSS
EASTERN DAKOTAS...SOON TO BE CROSSING INTO WRN MN. THIS SURGE OF
WAA ASSOCIATED WITH STRONG LOW LEVEL FN VECTOR RESPONSE TO
FRONTOGENESIS AND 45KT LOW LEVEL JET WEAKENS AS IT PROGRESSES
EASTWARD BUT RESTRENGTHENS TONIGHT. THE NOSE OF THE 85H JET BRUSHES
SOUTHWEST AND WEST CENTRAL WI TOWARD/AFTER MIDNIGHT. ALTHOUGH
UPSTREAM MID-LEVEL MOISTURE NOT IMPRESSIVE ON WATER VAPOR
IMAGERY...OBVIOUSLY ENOUGH TO INTERACT WITH STRONG WAA TO CAUSE
CONVECTION. UPSTREAM PWAT VALUES AROUND 1.5 INCHES EXPECTED TO PUSH
INTO SOUTHERN WI LATER TODAY AND TONIGHT. ALSO BOTH GFS AND NAM
SHOWING LAYER Q-VECTOR CONVERGENCE SPREADING INTO WESTERN WI
OVERNIGHT. 00Z WRF-NMM ALSO HAS GOOD HANDLE ON UPSTREAM ONGOING
CONVECTION AND CARRIES ISOLD -SHRA/-TSRA INTO WESTERN CWA LATER
TONIGHT. TOO MUCH TO IGNORE SO PER COORDINATION WITH ARX...WL ADD
SMALL POPS FOR CONVECTION FOR WESTERN AREA LATER TONIGHT. AT THIS
POINT EXPECT MAIN WARM AIR ADVECTION TO REMAIN UPSTREAM...BUT IF IT
SHIFTS FARTHER INTO WI...THEN POPS MAY NEED TO BE BUMPED EVEN EVEN
MORE FOR TONIGHT.
WEDNESDAY - CONFIDENCE...MEDIUM
500 MILLIBAR RIDGE AXIS SHIFTS A BIT FURTHER EAST FROM THE PLAINS.
NAM AND GFS SHOW A MORE PRONOUNCED WAA SIGNATURE INTO WESTERN WI
THAN DOES THE ECMWF. BUFKIT SOUNDINGS SHOWS MEAGHER ELEVATED
INSTABILITY ABOVE 11K FEET WITH VERY DRY LOW LEVELS. WILL GO WITH
THE DRY ALLBLEND POPS FOR NOW. 925 TEMPS ARE IN THE 23-26C
RANGE...SO MID 80S TO LOW 90S WEST SEEM PLAUSIBLE.
THURSDAY - CONFIDENCE...MEDIUM
591-593DM ELONGATED UPPER RIDGE ACROSS THE AREA. SSW WINDS WILL
HELP BOOST TEMPS A BIT FURTHER...WITH LOW 90S A BIT MORE
PREVALENT. NAM SHOWS TIGHTER GRADIENT WITH A BIT STRONGER WIND
REGIME. WILL LEAN A BIT MORE TOWARDS THE GFS/ECMWF SOLUTION AT
THIS TIME.
FRIDAY - CONFIDENCE...MEDIUM
REMNANTS OF ISAAC PROGGD TO BE ANYWHERE FROM ARKANSAS
TO MISSOURI...BUT REGARDLESS OF THE SOLUTION THE QPF SHIELD
EXPECTED TO REMAIN TO OUR SOUTH. POTENTIALLY WARMEST 925 TEMPS OF
THE WEEK WITH READINGS IN THE 27-29C RANGE. ALLBLEND TEMPS LOOK
TOO COOL GIVEN THIS...SO WILL BOOST A BIT MORE.
SATURDAY AND SUNDAY - CONFIDENCE...LOW TO MEDIUM
THE GEMNH AND 00Z ECMWF SHOW THE REMNANTS OF ISAAC GETTING CLOSE
ENOUGH TO BRING PRECIP INTO SRN WI. 12Z ECMWF AND 00Z GFS BOTH
WEAKEN AND SHIFT CIRCULATION INTO OHIO VALLEY. 12Z ECMWF AND 00Z GFS
SHOW 588-591DM UPPER RIDGE STILL IN CONTROL SATURDAY WITH SOME
FLATTENING OF THE FLOW FOR SUNDAY. HAVE RETAINED ALLBLEND POPS FOR
THE SOUTHERN CWA TO ACCOUNT FOR THE POTENTIAL ASSOCIATED WITH THE
ISAAC REMNANTS.
SUNDAY NIGHT AND MONDAY - CONFIDENCE...LOW TO MEDIUM
WEAK VORTICITY MAXIMA ALONG WITH A FRONTAL BOUNDARY MAY BE ENOUGH
TO GENERATE A FEW SHRA/TSRA...SO SMALLISH ALLBLEND POPS APPEAR
REASONABLE.
&&
.AVIATION/18Z TAFS/...THE CHANCES OF ELEVATED CONVECTION FM THE W
AFFECTING THE WRN PART OF THE FCST AREA HAS INCREASED...SO WL BE
ADJUSTING TAFS ACCORDINGLY. LOWER-END VFR CIGS IN THE E RIGHT NOW
SHOULD DISSIPATE THIS EVENING.
JS/MG
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1241 PM CDT TUE AUG 28 2012
.SHORT TERM...THROUGH TONIGHT
1043 AM CDT TUE AUG 28 2012
UPPER LEVEL SHORTWAVE MOVING THROUGH MINNESOTA ALONG WITH TWO
DIFFERENT AREAS OF SHOWERS/STORMS. FIRST IS ASSOCIATED WITH
WEAKENING OVERNIGHT LLJ/ELEVATED INSTABILITY ACROSS SOUTHERN
MINNESOTA. LATEST RADAR AND SATELLITE TRENDS CONTINUE TO SHOW A
DECREASE. SLIGHT CHANCES MAINLY WEST OF THE MISSISSIPPI RIVER LOOK
ON TRACK.
OTHER FEATURE OF NOTE IS AN AREA OF FRONTOGENESIS THAT IS
MAXIMIZED IN THE 600-500 MB LAYER MOVING THROUGH EASTERN
MINNESOTA. ISENTROPIC LIFT ON THE 315K SURFACE INCREASES AS WELL
BY 21Z AND THE LATEST 28.12Z NAM AND RAP SHOW THIS SLIDING INTO
WESTERN WISCONSIN THIS AFTERNOON ALONG WITH MOST UNSTABLE CAPES IN
THE 500 TO 1000 J/KG RANGE. HOWEVER...THIS WILL HAVE TO CONTEND
WITH SOME DRIER LOW-LEVEL AIR AND A GENERAL WEAKENING TREND...BUT
STILL WARRANTS LOW-END CHANCES ALONG MAINLY ALONG AND NORTH OF
I-90 IN WISCONSIN. LATEST MESO-MODELS ARE ALSO ON TRACK WITH
THIS FEATURE...KEEPING PRECIPITATION EAST OF THE MISSISSIPPI RIVER AS
WELL. GIVEN MORE CLOUDS AND CHANCE OF SHOWERS/STORMS ACROSS THESE
AREAS...LOWERED HIGHS A FEW DEGREES TO THE 80-83 DEGREE RANGE.
.LONG TERM...THURSDAY NIGHT THROUGH LABOR DAY
345 AM CDT TUE AUG 28 2012
THE 28.00Z MODELS CONTINUE TO STRUGGLE ON WHERE THE REMNANTS OF
ISAAC WILL ULTIMATELY END UP. THEY ARE NOW TRYING TO BRING SOME OF
THIS MOISTURE IN OUR FAR SOUTHERN AREAS ON SATURDAY AND SATURDAY
NIGHT. ITS TRACK ON LAND LOOKS A BIT SIMILAR TO AN UNNAMED TROPICAL
STORM IN 1955...HURRICANE ELENA /1985/...AND HURRICANE GUSTAV
/2008/. IN ALL THREE OF THESE SYSTEMS...THE PRECIPITATION STAYED
SOUTH OF THE FORECAST AREA.
FOR SUNDAY NIGHT INTO LABOR DAY...THE MODELS CONTINUE TO MOVE A
COLD FRONT THROUGH THE AREA. THE GFS CONTINUE TO GENERATE SOME
PRECIPITATION WITH ITS PASSAGE. MEANWHILE THE ECMWF NOW HAS THIS
FRONTAL PASSAGE DRY.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1241 PM CDT TUE AUG 28 2012
MAIN FORECAST CONCERNS THIS TAF PERIOD ARE PRECIPITATION CHANCES
OVERNIGHT AT KRST/KLSE. INCREASING MOISTURE TRANSPORT AXIS
BECOMES CENTERED TOWARDS SOUTHEAST MINNESOTA STARTING AFTER 03Z
ALONG WITH WEAK TO MODERATE INSTABILITY AND ISENTROPIC LIFT...ALL
OF WHICH SHOULD AID DEVELOPMENT OF SCATTERED SHOWERS/STORMS. MOST
OF THE CLOUD BASES WOULD REMAIN VFR...IN THE 6 TO 8 KFT RANGE.
HOWEVER...IN ANY OF THE STRONGER SHOWERS COULD SEE BRIEF MVFR
PERIODS. FOR NOW HAVE INTRODUCED A VCSH BEGINNING AFTER 05Z AT
KRST AND 07Z AT KLSE....ENDING A FEW HOURS POST SUNRISE AS THE
OVERNIGHT LOW-LEVEL JET WEAKENS. IF PRECIPITATION DOES MATERIALIZE
AND CLOUDS CLEAR BEFORE SUNRISE...COULD SEE PERIOD OF FOG/STRATUS.
OTHERWISE...MIXING WILL COMMENCE WEDNESDAY MORNING GIVING WAY TO
MOSTLY SUNNY SKIES.
&&
.FIRE WEATHER...THURSDAY
345 AM CDT TUE AUG 28 2012
THE SOUTHWEST WINDS WILL CLIMB INTO THE 15 TO 20 KNOT RANGE AND
RELATIVE HUMIDITIES WILL FALL INTO THE 20 TO 30 PERCENT RANGE.
THIS WILL LIKELY DRY OUT THE FINE FUELS RAPIDLY ESPECIALLY IN THE
DROUGHT AREAS. AS A RESULT...CONCERNED THAT THIS COULD BE AN
ACTIVE FIRE WEATHER DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
345 AM CDT TUE AUG 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZT
LONG TERM...BOYNE
AVIATION...ZT
FIRE WEATHER...BOYNE