Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/21/12
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
932 AM EDT SUN AUG 19 2012
.DISCUSSION...
...A FEW STRONG STORMS POSSIBLE AGAIN THIS AFTERNOON...
TODAY...MORNING SOUNDINGS SHOW ONLY A COUPLE OF MINOR DIFFERENCES
FROM YESTERDAY. ONE IS THE MEAN LOW LEVEL WIND FLOW WHICH IS
SLIGHTLY WEAKER. THE OTHER IS THE 700 MB TEMPERATURE WHICH IS
ABOUT A DEGREE AND A HALF WARMER.
THE LATEST RAP ANALYSIS SHOWS A WEAK VORT MAX NEAR THE WEST CENTRAL
FLORIDA COAST...BUT DEBRIS CLOUDINESS LOOKS MINIMAL.
WITH MOISTURE UNCHANGED FROM YESTERDAY...LITTLE INHIBITION OF
SURFACE HEATING AND DEEP LAYER WEST/SOUTHWEST FLOW...EXPECT
SHOWERS/STORMS TO MARCH RIGHT ON ACROSS THE PENINSULA AGAIN TODAY.
THE SLIGHTLY WARMER 700 MB TEMPERATURE AND SLIGHTLY WEAKER LOW LEVEL
FLOW SHOULD DELAY THIS PROGRESSION BY AN HOUR OR TWO COMPARED TO
SATURDAY.
MOS GUIDANCE AND THE MESOSCALE MODELS DO NOT SHOW AN EAST COAST SEA
BREEZE...BUT MID-LATE AFTERNOON LAKE/OUTFLOW BOUNDARY INTERACTIONS
WILL LIKELY PRODUCE ISOLATED STRONG STORMS. THE GREATEST CHANCE FOR
THIS SHOULD BE ALONG THE TREASURE COAST TO CAPE CANAVERAL.
DO NOT SEE ANYTHING SIGNIFICANT TO UPDATE IN THE FORECAST/GRIDS.
&&
.AVIATION...
TRENDS INDICATE THAT THE WEST TO EAST MARCH OF SHOWERS/STORMS ACROSS
THE PENINSULA WILL BE SLIGHTLY LATER THAN YESTERDAY...NEAR MIDDAY
KLEE...17-18Z KSFB-KMCO-KISM...18-19Z KDAB-KTIX AND 19-21Z
KMLB-KSUA. OUTSIDE THESE SHOWERS/STORMS IT WILL BE VFR EXCEPT FOR
BRIEF MVFR CEILINGS AS CUMULUS FORM THIS MORNING.
&&
.MARINE...
TODAY...SOUTHWEST FLOW POSING NO WIND WAVE PROBLEMS EXCEPT WELL
OFFSHORE WHERE FLOW A LITTLE OVER 10 KNOTS WILL CAUSE CHOPPY
CONDITIONS FOR SMALL CRAFT RETURNING TO SHORE. SCATTERED STORMS
MOVING OFFSHORE THIS AFTERNOON WILL BE CAPABLE OF PRODUCING
DANGEROUS CONDITIONS THOUGH...WITH FREQUENT LIGHTNING STRIKES AND
GUSTY WINDS TO AROUND 35 KNOTS. A COMPREHENSIVE OUTFLOW BOUNDARY
MAY AGAIN EVOLVE AND PUSH WELL OFFSHORE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...LASCODY
IMPACT WEATHER...WIMMER
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
143 AM EDT Sun Aug 19 2012
.NEAR TERM [through Tonight]...
The PoP forecast is tricky tonight as most of the guidance does not
appear to have a very good handle on the large mass of rain with
embedded thunderstorms approaching from the west. The 18z NAM does
not know that this rain exists, and most of the hi-res guidance is
struggling as well. The HRRR seems to have a fair handle on the
current rain area though and moves it eastward overnight while
gradually weakening. Although gradual weakening is expected, it will
likely move into at least the western part of the forecast area
overnight, so PoPs were raised into the likely range (60-70 percent)
roughly from the Apalachicola river westward, with 30-50 percent
PoPs east of there. This is only round 1 of what may be several
rounds of showers with embedded thunderstorms over the next few days
with a tropical airmass in place and the base of a broad upper level
trough affecting the area.
$$
.SHORT TERM [Sunday through Monday Night]...
Looks like a very unsettled period with the broad trough over the
eastern CONUS deepening as several impulses drop southeastward from
the plains into the base of the trough. The axis of the trough will
remain west of the local region which will tap into the tropical
moisture associated with Helene or its remnants in the deep layer
southwest flow. The GFS continues to show the upper jet dipping well
into the southeastern states Sunday into Monday placing the
Tri-State area within the right entrance region. SPC`s day 2
discussion currently mentions this put no highlighted area for a
severe risk at this time. This will need to be monitored closely. At
the surface, a cold front will approach from the northwest pushing
into our western zones Monday possibly becoming quasi-stationary late
Monday or Tuesday. As mentioned in an earlier discussion, this could
set the stage for a heavy rain event with localized flooding.
Understandably PoPs will be rather high during this period and will
generally go above numerical guidance. Max temps will be held down a
few degrees with the extensive cloud cover and convective activity.
&&
.LONG TERM [Tuesday through Saturday]...
With the mean upper level trough expected to remain quite persistent
across the eastern half of the U.S. through much (if not all) of the
upcoming week, impulses of energy rounding the base of the trough
over the Southeast will combine with plenty of deep layer moisture
to keep above normal PoPs in the fcst throughout much of the
extended period. Additionally, the likely remnants of Tropical Storm
Helene (which is still progged to move into southern Mexico, well
away from our region), may still play an important role in our fcst
before the week is over. While there are still plenty of
discrepancies between the global models (and run to run differences
within each model) over timing and potential moisture influx, the
simple presence of the steep upper level trough, will likely pull in
some deep layer tropical moisture into our region from the SW by mid
to late next week. Now, the latest runs of the GFS (00 UTC) and ECMWF
(12 UTC Thu), are back to showing some potential for a "break" in
the organized convection later on Tue. and possibly lasting into
Thu., but am not ready to buy into this solution just yet, given the
numerous changes and uncertainty surrounding Helene. Should this
become a trend that all of the global models begin embracing, then
PoPs can be adjusted downward at a later time. Also, with the
increased cloud cover which is still expected during the day, the
effects of the more typical afternoon sea breeze will be somewhat
limited (except for possibly Tue aftn thru Thu.), so high temps
should average a bit below climo values through much of the period.
While this does NOT appear to be the best stretch of "beach weather"
by any means, the potential of a good stretch of widespread rainfall
will certainly help many areas to continue to chip away at our long
term ongoing drought. Please stay tuned to the latest fcsts from the
National Weather Service, as this pattern may need some fine tuning
once the global models come into better agreement with each other,
and maintain more run to run consistency.
&&
.AVIATION [through 06z Monday]...
Updated at: 140am
Confidence is low for this set of TAFs as there is a fair amount of
disagreement amongst the models as to how SHRA and TS will evolve
today. For now, we went with the idea of MVFR CIGS developing late
tonight and lingering into the morning hours, with VFR thereafter.
As far as timing of SHRA and TS, we went with the general idea of
rapid development in the 09-12z timeframe - beginning at the Gulf
coast and then spreading inland. Although there is disagreement on
location and timing of convection for much of the day, models do
seem to agree on an early start to things. Some MVFR/IFR is likely
to exist in and near SHRA and TS for the bulk of the day. However,
confidence in continued activity beyond about 18z is low, so that
time frame was kept VFR across the board for now at terminals.
&&
.MARINE...
Winds will be from the southwest at least through mid-week with
winds and seas gradually increasing to cautionary levels by Tuesday
as the pressure gradient tightens ahead of a cold front. This front
will also bring numerous showers and thunderstorms to the coastal
waters. Winds and seas may subside below headline criteria on
Wednesday.
&&
.FIRE WEATHER...
Typical of this wet summer pattern, afternoon relative humidities
will remain well above critical levels over the next several days
and, and therefore, conditions will continue to remain safely
above red flag levels.
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...DVD
SHORT TERM...Barry
LONG TERM...Gould
AVIATION...Lamers
MARINE...Barry
FIRE WX...Block
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
215 AM EDT SUN AUG 19 2012
.UPDATE...
NO SIGNIFICANT CHANGES SO FAR BUT PLANNING ON UPPING POPS OVERNIGHT.
RECENT HRRR RUNS AND 12Z AND 18Z GFS REALLY UPPING POTENTIAL FOR
OVERNIGHT SHRA/TSRA. HRRR TIMING ONSET AT ATL METRO ABOUT 06Z WITH
GFS A LITTLE LATER. OTHER MODELS INCLUDING LOCAL 4KM WRF AND NCEP
4KM WRF NMM NOT SO OPTIMISTIC ABOUT PRECIP. BEST H8 WAA ON GFS
PROGGED MORE OVER MIDDLE GA WITH SOME WAA AT HIGHER LEVELS FURTHER
NORTH.
SNELSON
&&
.PREV DISCUSSION... /ISSUED 321 PM EDT SAT AUG 18 2012/
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
EXPECT AN ACTIVE WEATHER PATTERN THROUGH THE SHORT TERM. SURFACE
ANALYSIS SHOWS A COLD FRONT NEAR A CARROLLTON TO ATLANTA TO ATHENS
LINE. EXPECT A STRONG UPPER DISTURBANCE OVER MS TO TRAVERSE THE AREA
AND SPARK ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND
SOUTH OF THE FRONT THROUGH MID EVENING. THIS ACTIVITY SHOULD
DIMINISH BY MIDNIGHT... BUT THE BREAK MAY BE SHORT LIVED AS A SERIES
OF DISTURBANCES BEGIN TO CARVE A LONG WAVE TROUGH ALONG THE LOWER MS
VALLEY REGION OVERNIGHT AND ON SUNDAY. AS A RESULT... EXPECT A VERY
ACTIVE SW FLOW ALOFT TO INTERACT WITH AN INCREASINGLY MOIST AND
UNSTABLE AIRMASS TO SPARK SCATTERED TO WIDESPREAD CONVECTION ACROSS
MUCH OF THE AREA STARTING EARLY ON SUNDAY AND CONTINUING THROUGH
MONDAY. THE GFS SHOWS A SURFACE LOW DEVELOPING ALONG THE STALLED
FRONT AND SWEEPING ACROSS THE STATE MONDAY NIGHT... WITH THE
TRAILING COLD FRONT FINALLY BRINGING SOME DRIER CONDITIONS TO AT
LEAST NORTH GA BY TUESDAY MORNING. AT THIS TIME...EXPECT THE
STRONGER STORMS TO OCCUR ON MONDAY AS THE UPPER TROUGH DEEPENS AND A
SURFACE LOW PUSHES INTO THE STATE DURING DAYTIME HEATING.
ALTHOUGH AMPLE CLOUD COVER AND WIDESPREAD SHOWERS SHOULD HELP
HINDER SEVERE STORM DEVELOPMENT ON SUNDAY AND MONDAY... THE
INCREASED FORCING EXPECTED ON MONDAY WARRANTS GREATER CONCERN FOR
MONDAY AFTERNOON AND EVENING. SPC DOES NOT HAVE THE FORECAST AREA
OUTLOOKED AT THIS TIME... BUT WILL MONITOR THIS POTENTIAL CLOSELY
GOING INTO MONDAY. OTHERWISE...LEANED TOWARD A MAV AND MET BLEND
FOR LOWS AND HIGHS THROUGH THE PERIOD WITH SOME UNCERTAINTY ON
TIMING AND COVERAGE OF CONVECTION AT THIS TIME.
39
LONG TERM /TUESDAY THROUGH SATURDAY/...
OVERALL GUIDANCE IN BETTER AGREEMENT THAN YESTERDAY WITH MAIN
INFLUENCING FEATURES FOR THE MAJORITY OF THE LONG TERM. THROUGH
TUESDAY BOTH THE GFS AND ECMWF KEEP THE MOISTURE FIELD SOUTH OF THE
NEARLY STATIONARY SFC FRONT ACROSS CENTRAL GEORGIA...WHICH
EVENTUALLY SAGS ACROSS SOUTHERN GEORGIA FOR WEDNESDAY INTO THURSDAY.
CURRENT POPS OF LOW END CHANCE IN THE SOUTH TO SLIGHT NORTHWARD
THROUGH THIS PERIOD SEEM REASONABLE. THE ECMWF HINTS AT A WEAK UPPER
LOW DRAWING MOISTURE IN A BIT FARTHER NORTHWARD THAN THE GFS ON
THURSDAY... BUT THERE IS DECENT UNCERTAINTY IN THIS SOLUTION THIS
FAR OUT SO WILL KEEP BEST CHANCE POPS IN SOUTH AND EAST PORTIONS.
WEAK SFC HIGH BUILDING INTO AREA NEAR END OF THE WEEK SHOULD LIMIT
CONVECTIVE DEVELOPMENT SO WILL ALSO CONTINUE THE CURRENT SLIGHT POPS
FOR THAT TIMEFRAME. NO SIGNIFICANT CHANGES NEEDED TO THE FORECAST
TEMPS AS LATEST MEX GUIDANCE KEEPING BETTER CONSISTENCY BETWEEN RUNS
THAN YESTERDAY. WITH ALL CONSIDERED...FORECAST LOOKS TO BE ON TRACK.
PREVIOUS DISCUSSION FOLLOWS...
03
PREVIOUS DISCUSSION ISSUED AT 426 AM EDT SAT AUG 18 2012/...
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CWA REMAINS UNDER THE INFLUENCE OF A LONGWAVE TROUGH AT THE
BEGINNING OF THE LONG TERM. LATEST GUIDANCE STILL BRINGS A WAVE
ACROSS THE CWA NEAR THE BEGINNING OF THE LONG TERM BUT ABOUT 12
HOURS EARLIER THAN SUGGESTED YESTERDAY WITH MODELS SHOWING SUNDAY
NIGHT NOW. ALTHOUGH NAM/GFS/ECMWF/SREF SHOW SOME REFLECTION OF A
SFC LOW ASSOCIATED WITH THIS DISTURBANCE...THE GFS IS BY FAR THE
STRONGEST AND APPEARS TO BE OVERDONE ON STRENGTH AND PRECIP. AT
LEAST THROUGH MONDAY...LEANED TOWARD THE NAM/ECMWF SOLUTION TO
ACCOUNT FOR THE OVERDONE GFS. MAIN IMPACT WAS TO POPS THAT ARE IN
THE SLIGHT CHANCE TO LIKELY CATEGORY THROUGH MONDAY AS OPPOSED TO
THE LIKELY AND CATEGORICAL POPS SUGGESTED BY THE GFS. AFTER THE
INFLUENCES FROM THE WAVE ON MONDAY MOVES OUT OF THE CWA...RAIN
CHANCES DECREASE. BEST MOISTURE REMAINS ACROSS SOUTHERN HALF OF
CWA SO HAVE CONTINUED TO SHOW BEST POPS ACROSS THAT AREA. BY
MIDWEEK...LONGWAVE TROUGH CONTINUES TO BREAK DOWN ACROSS THE AREA
AND BEST MOISTURE CONTINUES TO SHIFT OFF TO THE EAST AS HIGH
PRESSURE PUSHES INTO THE CWA AT THE SFC. THIS WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE ACROSS THE NORTH AND CHANCE ACROSS THE
SOUTHERN HALF OF THE CWA.
MEX MAX TEMPS ARE SLIGHTLY HIGHER THAN PREVIOUS RUN. LIKE THIS TREND
AND HAVE EVEN NUDGED MAX TEMPS UP A DEGREE IN SOME PLACES. MIN TEMPS
APPEAR A LITTLE COOL DURING THE WORK WEEK...SO HAD TO MAKE SOME
ADJUSTMENTS UPWARD HERE TOO.
11
AVIATION...
06Z UPDATE...
MAINLY MVFR CIGS GENERALLY 020-030 SCT-BKN THROUGH 12Z...THEN VFR
REMAINDER OF PERIOD. VFR VSBYS OVER TAF SITES. A COLD FRONT REMAINS
NEARLY STATIONARY ACROSS THE ATLANTA METRO AREA... AND WITH AN
ACTIVE WESTERLY FLOW ALOFT. SHOWERS AND THUNDERSTORMS CONTINUE TO
DIMINISH...BUT BROAD AREA OF RAIN PERSIST INTO EASTERN ALABAMA.
MAINLY VFR CONDITIONS BEHIND PRECIP SHIELD. AS NEXT WAVE MOVES ALONG
FRONT...PROB30 FROM 18Z FOR MORE SHRA/TSRA...BUT VCSH FROM 12Z-18Z.
WINDS EXPECTED TO REMAIN WEST TO NORTHWEST UNDER 10KTS.
//ATL CONFIDENCE...
06Z UPDATE...
MODERATE CONFIDENCE ON CONVECTION AND TIMING. HIGH CONFIDENCE ON
ALL OTHER ELEMENTS.
37
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 68 86 68 84 / 30 50 60 60
ATLANTA 69 86 69 83 / 30 60 60 60
BLAIRSVILLE 62 80 66 80 / 20 30 50 50
CARTERSVILLE 68 85 67 84 / 30 50 60 60
COLUMBUS 72 87 70 84 / 30 60 70 70
GAINESVILLE 68 85 68 83 / 30 50 60 60
MACON 71 88 70 86 / 30 60 70 70
ROME 69 87 68 85 / 30 40 50 60
PEACHTREE CITY 68 86 67 84 / 30 60 60 60
VIDALIA 72 89 72 85 / 30 60 70 70
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS INDIANAPOLIS IN
812 PM EDT MON AUG 20 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 347 PM EDT MON AUG 20 2012
UPPER TROUGHING OVER THE REGION WILL GRADUALLY DEPART TONIGHT INTO
EARLY TOMORROW...AND RIDGING AT THE SURFACE WILL REASSERT
DOMINANCE FOR MUCH OF THE REMAINDER OF THE FORECAST PERIOD...WITH
WEAK QUASI ZONAL FLOW ALOFT BECOMING MORE ANTICYCLONIC LATER IN
THE WEEK. TEMPERATURES WILL GRADUALLY WARM BACK TO NEAR OR JUST
ABOVE NORMAL VALUES THIS WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 607 PM EDT MON AUG 20 2012
QUICK UPDATE WITH RESPECT TO CONVECTIVE COVERAGE ACROSS THE FORECAST
AREA EARLY THIS EVENING IN VICINITY OF THE UPPER LEVEL WAVE.
COVERAGE ACROSS THE NORTHERN WABASH VALLEY IS GREATER THAN
ISOLATED...AND HRRR GUIDANCE HINTING AT THIS ACTIVITY TO CONTINUE
MOVING EAST ACROSS FAR NORTHERN COUNTIES OVER THE NEXT FEW HOURS
BEFORE DIMINISHING. HAVE THEREFORE BUMPED UP TO SCATTERED POPS IN
THE NORTHERN COUNTIES THROUGH 01Z...WITH ISOLATED WORDING CONTINUING
ELSEWHERE. CONVECTION WILL BEGIN TO DIMINISH TOWARDS SUNSET AS
HEATING IS LOST AND WAVE SHIFTS EAST.
REST OF FORECAST UNCHANGED....PREVIOUS DISCUSSION FOLLOWS BELOW.
FOCUS IS ON ENDING OF THUNDERSTORMS. GUIDANCE IS SIMILAR AND A
BLEND IS USED.
ISOLATED THUNDERSTORMS ARE DEVELOPING...BUT STRUGGLING IN A WEAKLY
FORCED ENVIRONMENT. ONLY THUNDERSTORMS OVER NORTHEAST ILLINOIS AND
NORTHWEST INDIANA...AIDED IN PART BY CONVERGENCE ALONG THE LAKE
BREEZE...ARE MAINTAINING ANY KIND OF SIGNIFICANT COVERAGE. THESE
MAY MANAGE TO PERSIST TO NEAR 00Z...BUT EXPECT THAT MOST ALL
CONVECTION WILL BE DONE BY THE START OF THE OVERNIGHT PERIOD...SO
WILL CARRY NO POPS AFTER 00Z.
ON TEMPS...PREFER NUMBERS JUST ABOVE CONSENSUS...NEAR
PERSISTENCE...AS THERE HAS BEEN LITTLE CHANGE IN THE AIRMASS FROM
YESTERDAY/LAST NIGHT. THIS AGREES FAIRLY WELL WITH LOW LEVEL
THICKNESSES...YIELDING LOW TO MID 50S AGAIN TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 347 PM EDT MON AUG 20 2012
FOCUS IS MAINLY TEMPS THROUGHOUT AS HIGH PRESSURE REASSERTS
ITSELF. GUIDANCE IS SIMILAR AND A BLEND IS USED.
GUIDANCE SUGGESTS ONE FINAL WEAK WAVE MAY BE DEPARTING THE AREA
EARLY TOMORROW...BUT AS IT SHOULD BE GONE BY PEAK HEATING...EXPECT
NO CONVECTIVE DEVELOPMENT OVER THE AREA BEYOND CUMULUS...AND WILL
KEEP DRY FORECAST. AS SURFACE HIGH BUILDS IN...THIS WILL CONTINUE
THROUGH THE REMAINDER OF THE SHORT TERM.
ON TEMPS...LOW LEVEL THICKNESSES RISE GRADUALLY THROUGHOUT THE
SHORT TERM...AND A STEADY WARMING TREND IS DEPICTED. NEAR TO JUST
ABOVE CONSENSUS NUMBERS DEPICT THIS WELL AND THIS WAS THE GENERAL
MAX/MIN TEMP TECHNIQUE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 142 PM EDT MON AUG 20 2012
FOCUS FOR THE EXTENDED WILL BE TEMPERATURES AND WHETHER OR NOT TO
MENTION ANY POPS.
MODELS IN GOOD AGREEMENT ON SOUTH AND SOUTHWEST LOW LEVEL FLOW AS
SURFACE HIGH PRESSURE BECOMES ANCHORED ACROSS THE EASTERN STATES.
THE RESULT WILL BE SLIGHTLY ABOVE NORMAL TEMPERATURES AND INCREASING
HUMIDITY. HOWEVER...THE MAIN COLD FRONT SHOULD BE FAR ENOUGH TO THE
NORTHWEST MONDAY TO BE A FACTOR...AND WITH DEEP MOISTURE
ABSENT...WILL HOLD OFF ON POPS AT THIS TIME...EVEN THOUGH LOW
COVERAGE THUNDERSTORMS WOULD NOT BE OUT OF THE REALM OF POSSIBILITY.
FELT THE CENTRAL REGIONAL INITIALIZATION TEMPERATURES LOOKED FINE.
&&
.AVIATION /DISCUSSION FOR THE 210000Z TAFS/...
ISSUED AT 630 PM EDT MON AUG 20 2012
SCATTERED CONVECTION CONTINUES OVER WESTERN INDIANA...ASSOCIATED
WITH AN UPPER WAVE DROPPING SOUTHEAST THROUGH THE MIDWEST.
CONVECTION APPEARS TO BE MAINLY DIURNALLY DRIVEN...AS OVERALL
FORCING QUITE WEAK. AS A RESULT...EXPECTING LINGERING CONVECTION TO
DISSIPATE WITHIN A COUPLE OF HOURS OF SUNSET...AROUND 210200Z. NOT
SURE AT THIS TIME WHETHER CONVECTIVE COVERAGE WILL BE ENOUGH TO
CONTINUE TO EXPLICITLY MENTION IN THE FORECAST. WILL MAKE A LAST
MINUTE CALL REGARDING THIS AT ISSUANCE TIME. CB CLOUD BASES AROUND
060.
OTHERWISE...SHOULD BE MORE LOW LEVEL MOISTURE AROUND DUE TO THE
SHOWER ACTIVITY...SO MVFR VISIBILITY RESTRICTIONS DUE TO LIGHT FOG
SEEM PROBABLE AFTER 210700Z OR SO. NO WIND ISSUES EXPECTED OUTSIDE
OF CONVECTION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/RYAN
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
651 PM CDT MON AUG 20 2012
...UPDATED AVIATION SECTION FOR 00Z TAFS...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 222 PM CDT MON AUG 20 2012
TONIGHT:
THE IMMEDIATE SHORT TERM FORECAST IS WHAT TO DO WITH POPS THIS EVENING.
NORTHWEST FLOW ALOFT AND OROGRAPHICALLY INDUCED CONVECTION ACROSS COLORADO WILL
CREATE A CLASSIC MCS LATE SUMMER TIME EVENT FOR FAR SW KANSAS. RIGHT
NOW THE MESOSCALE MODELS (NAM, WRF) SHOWS THAT THE BEST 310K ISENTROPIC
LIFT AND WARM AIR (THETA-E) ADVECTION WILL BE LOCATED ACROSS THE SOUTHWESTERN
COUNTIES. THIS AREA IS ALSO CLOSER TO AN APPROACHING 80 KT 250 HPA JET
STREAK MOVING ACROSS THE REGION TONIGHT. THE MOST RECENT HRRR IS QUITE
AGGRESSIVE WITH COMPOSITE REFLECTIVITIES AND ASSOCIATED PRECIPITATION
TOWARDS 05Z (MIDNIGHT) FOR THE CENTRAL COUNTIES. FOR NOW, WILL HOLD
OFF ON THIS SOLUTION SINCE THIS MODEL MIGHT BE OVERDOING THE RESULTANT
COLD POOL FROM THE CONVECTIVE SCHEME. HAVE DOUBTS FOR SEVERE WEATHER
AS DEWPOINTS ARE MAINLY IN THE 40S DEG F. THERE ARE SOME HIGHER DEWPOINTS
(LOWER 50S DEG F) ACROSS THE PANHANDLES, BUT THIS BETTER MOISTURE SHOULD
STAY SOUTH OF THE REGION. KINEMATIC PROFILES SUGGEST THE POSSIBILITY
OF SEVERE WEATHER WITH 0-6 KM BULK SHEAR FORECAST TO BE ABOUT 45 KT
AND ANVIL LEVEL STORM RELATIVE WINDS AROUND 80 KT. THE FLY IN THE OINTMENT
FOR THIS EVENING IS MEAGER CAPE ASSOCIATED WITH MARGINAL BOUNDARY
LAYER DEWPOINTS. 700-500 HPA LAPSE RATES AROUND 7.5 C/KM AND 500-300
HPA LAPSE RATES AROUND 6.7 C/KM IN COMBINATION WITH 500 J/KG OF
SBCAPE SUGGEST MARGINAL HAIL FOR ANY SUSTAINED UPDRAFT - MAINLY
TOWARDS ELKHART.
TOMORROW:
KEPT THE IDEA OF LOWER TEMPERATURES ACROSS THE SW COUNTIES AS TEMPERATURES
SHOULD BE MODERATED BY THE ANTICIPATED RAINFALL ACROSS THE REGION. I
HAVE LOWER 80S DEG F FOR THE SOUTHWEST COUNTIES AND MID TO UPPER 80S
DEG F ELSEWHERE. THINK THE 12Z NAM IS OVERDOING TEMPS ACROSS THIS REGION.
MAX CLIMO FOR THE REGION IS AROUND 88 DEG F FOR TOMORROW. THE 12Z NAM
IS SUGGESTING THE POSSIBILITY FOR CONVECTION ACROSS FAR WESTERN KANSAS
ALONG THE LEE SURFACE TROUGH FOR TOMORROW EVENING. WILL PUT SLIGHT POPS
IN THE GRIDS FOR NOW. NOT TOTALLY CONFIDENT AS UPPER LEVEL DYNAMICS
ARE FORECAST TO BE ON THE WEAKER SIDE TOMORROW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 246 PM CDT MON AUG 20 2012
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING, WILL PHASE OUT 20 PERCENT
SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS FROM OUR WESTERN
FORECAST POINTS NEAR SYRACUSE AND ELKHART BY 06Z. THE TROUGH THE
AFTERNOON CONVECTION WILL TRIGGER ON LATE TUESDAY WILL SLOWLY
DISSIPATED DURING THE EARLY OVERNIGHT PERIOD TUESDAY NIGHT.
ANOTHER SHORT WAVE WILL COME THROUGH THE NORTHWEST FLOW ALOFT LATE
WEDNESDAY AND GENERATE ANOTHER LOW PRESSURE TROUGH NEAR OUR WESTERN
BORDER. LOW 20 POPS FOR ELEVATED THUNDERSTORMS WILL RESULT AFTER
21Z WEDNESDAY, AND SPREAD EASTWARD DURING THE EVENING WEDNESDAY.
THE SURROUND OFFICES SEEMED TO FAVOR 30 PERCENT CHANCE POPS WED, SO
I STUCK WITH 30 POPS FOR ALL AREAS EXCEPT 40 PERCENT POPS IN IN OUR
EASTERN 2 TIERS OF COUNTIES, EAST OF A LINE FROM LARNED TO COLDWATER
WED NIGHT. MOST OF THESE THUNDERSTORMS WILL LIKELY BE ELEVATED AND
ONLY PRODUCE RAINFALL IN THE 0.10 RANGE IN OUR SOUTHEAST ZONES, BUT
SOMEWHAT LOWER AND ONLY IN THE 0.02 TO 0.06-INCH RANGE UP NORTH AND
TO THE WEST. THOSE UPPER WAVES ARE JUST STACKED ONE AFTER ANOTHER,
SO PRECIP CHANCES IN THE 20 TO 30 PERCENT RANGE WILL CONTINUE INTO
THURSDAY, BUT INCREASE IN THE 40 PERCENT RANGE ACROSS OUR EASTERN
1/3RD OF THE CWA, BASICALLY EAST OF A WAKEENEY TO KINSLEY TO MEADE
LINE. A STEADY SOUTHERLY FLOW WILL BRING MID 60S DEW POINTS INTO
THAT AREA THURSDAY AFTERNOON, AND A SYNOPTIC SCALE UPPER WAVE WILL
CROSS JUST NORTH OF OUR CWA THURSDAY NIGHT.
FRIDAY SHOULD SEE A LITTLE RELAXING/WEAKENING OF THE STRENGTH OF
THE PASSING UPPER WAVE, WITH ONLY OUR SOUTHEAST ZONES NEAR MEDICINE
LODGE CARRYING 30 POPS. AS A WARM FRONT NUDGES NORTH FRIDAY NIGHT
AND STEADY UPPER SCALE LIFT STAYS OVER WESTERN KANSAS, MUCH OF THE
CWA COULD SEE HIGH BASED SHOWERS AND ISOLATED STORMS FRIDAY NIGHT.
A CHANCE CATEGORY 30 PERCENT POPS WILL COVER MUCH OF THE EASTERN
HALF OF THE FORECAST AREA, WHILE 20 POPS WILL BE OVER THE SOUTHWEST
ZONES FRI NT. SATURDAY, SATURDAY NIGHT AND SUNDAY ALL LOOK GOOD FOR
30 TO 40 PERCENT RAIN CHANCES IN OUR EASTERN HALF OF THE CWA, WITH
EVEN OUR SOUTHWEST COUNTIES HAVING A 20 PERCENT CHANCE SATURDAY
NIGHT. SUNDAY WAS SOMEWHAT QUESTIONABLE AS TO WHERE THE UPPER WAVE
WILL BE, BUT OUR EASTERN-MOST ZONES FROM HAYS TO PRATT TO MEDICINE
LODGE WILL STILL HAVE 20 POPS. BY SUNDAY, THE LAST IN A SERIES OF
UPPER WAVES COULD BE FAR ENOUGH EAST TO LEAVE POPS OUT OF OUR EAST
ZONES ALL TOGETHER SUNDAY. WILL HAVE TO SEE THE NEXT MODEL RUN TO
DETERMINE IF PRECIP CHANCES ARE WARRANTED SUNDAY.
AS FOR TEMPERATURES, I ACCEPTED WHAT THE CREXTENDFCST_INIT PROCEDURE
GAVE ME. BASICALLY, FOR WEDNESDAY THROUGH SUNDAY, HIGH TEMPERATURES
WILL BE IN THE MID TO UPPER 80S ACROSS OUR NORTHERN HALF OF THE CWA,
AND FROM THE UPPER 80S TO LOWER 90S IN OUR SOUTHERN HALF. MINIMUM
TEMPERATURES WILL START OUT IN THE LOWER 60S WEDNESDAY, AND WARM TO
THE MID 60S TO LOWER 70S (SE) FRIDAY THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 647 PM CDT MON AUG 20 2012
A FEW RAIN SHOWERS WILL AFFECT THE GCK TERMINAL THROUGH THE MID
EVENING HOURS AS A WEAK UPPER LEVEL DISTURBANCES CONTINUES TO MOVE
SOUTHEAST ACROSS WESTERN KANSAS. OTHERWISE...MID AND HIGH LEVEL
CLOUD COVER WILL PREVAIL THROUGH THE REST OF TONIGHT...AND NO MVFR
OR BELOW CEILINGS ARE EXPECTED TO FORM. WINDS WILL REMAIN OUT OF
THE SOUTH TO SOUTHEAST TONIGHT AND TOMORROW.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 85 61 86 / 10 10 10 20
GCK 59 84 61 88 / 20 10 20 20
EHA 60 81 62 88 / 40 20 20 20
LBL 61 82 62 88 / 30 10 20 20
HYS 58 89 61 90 / 0 10 10 20
P28 61 89 62 89 / 10 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS PADUCAH KY
320 PM CDT SUN AUG 19 2012
.UPDATE...
ISSUED AT 303 PM CDT SUN AUG 19 2012
SMALL CLUSTER OR TWO OF SHOWERS AND POSSIBLY A RUMBLE OR TWO OF
THUNDER HAVE DEVELOPED OUT OVER PORTIONS OF SE MO...ESP NORTH AND
WEST OF POPLAR BLUFF. THEREFORE...WILL UP POPS UP INTO THE SCT
RANGE FOR THE NEXT FEW HOURS.
UPDATE ISSUED AT 1104 AM CDT SUN AUG 19 2012
BASED UPON THE LATEST RADAR/STLT/NAM AND RUC PROGGED SOUNDINGS FOR
THE REST OF TODAY...AM INCLINED TO REDUCE SHOWER/STORM CHANCES
DOWN TO AROUND 10 PERCENT. EVEN THO WEAK IMPULSE ALOFT IS
APPROACHING IN CYCLONIC NW FLOW..THERE JUST SEEMS TO BE NO
INSTABILITY OR OVERALL MOISTURE TO WORK WITH /ESP BELOW 8000 FT/.
CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLE HERE AND THERE...BUT
CAPES PROGGED TO REMAIN LESS THAN 100 J/KG THIS AFTN...SO THUNDER
CHCS LOOK PRACTICALLY NIL.
ALSO...UPDATED THE AVIATION SECTION BELOW FOR THE UPCOMING 18Z
TAF FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 303 PM CDT SUN AUG 19 2012
BASED GENERALLY ON SAME REASONING AS IN THE UPDATE SECTION ABOVE...
AM INCLINED TO REDUCE SHOWER/STORM CHANCES DOWN TO AROUND 10
PERCENT FOR MONDAY/TUE ALSO. AGAIN...EVEN THO WEAK IMPULSES ALOFT
WILL CONTINUE TO ROTATE SSE WITHIN FAIRLY DEEP TROF /CYCLONIC FLOW/
OVER THE OHIO VALLEY...THERE JUST SEEMS TO BE VERY LITTLE
INSTABILITY AND OVERALL MOISTURE TO WORK WITH///ESP IN THE LOWEST
7000 TO 10000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLES HERE
AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN 400 J/KG FOR THE
MOST PART THROUGH TUE...SO THUNDER CHCS CONTINUE TO LOOK PRACTICALLY
NIL.
AS FAR AS TEMPS ARE CONCERNED...WILL CONT TO IGNORE THE OBVIOUSLY
COLD MAV TEMP BIAS. EVEN THE MET MOS TEMPS SEEM TO BE RUNNING A
FEW DEGREES TOO COOL TODAY. HOWEVER...GIVEN THE FACT THAT THERE
MAY BE MORE IN THE WAY OF MID CLOUDS MONDAY...WILL STAY CLOSE TO
THE MET MOS NUMBERS TONIGHT THROUGH TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN AUG 19 2012
FOR WEDNESDAY THROUGH THURSDAY NIGHT...MODELS SHOW A BROAD UPPER
LEVEL RIDGE OVER THE REGION WITH HIGH PRESSURE AT THE SURFACE. THIS
WILL KEEP CONDITIONS DRY ACROSS THE PAH FORECAST AREA. SOUTHERLY
FLOW AND PLENTY OF SUNSHINE WILL KEEP TEMPERATURES NEAR NORMAL WITH
HIGHS IN THE UPPER 80S AND LOWS IN THE LOWER TO MIDDLE 60S.
MODELS DIVERGE ON FRIDAY. THE 00Z ECMWF SHOWED AN UPPER LEVEL LOW
SLIDING INTO THE AREA...BRINGING SOME QPF TO MAINLY SOUTHERN
PORTIONS OF THE PAH FORECAST AREA. THE 12Z ECMWF IS MUCH LESS
PRONOUNCED WITH THIS FEATURE AND KEEPS ANY PRECIP JUST WEST OF OUR
AREA. THE LATEST GFS...ON THE OTHER HAND...BRINGS A SURFACE LOW OUT
OF THE PLAINS AND BRINGS CHANCES OF PRECIP INTO OUR WESTERN COUNTIES
FRIDAY NIGHT AND THE ENTIRE PAH FA ON SATURDAY. MODELS LACK ANY
REAL CONSISTENCY...SO JUST STUCK WITH SLIGHT TO VERY LOW CHANCE
POPS FOR NOW...WITH SLIGHTLY HIGHER POPS ACROSS OUR SOUTHERN
COUNTIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 303 PM CDT SUN AUG 19 2012
BASED UPON THE LATEST RADAR/STLT/NAM AND RUC PROGGED SOUNDINGS FOR
THE REST OF TODAY THROUGH EARLY AFTN MON...AM INCLINED TO REDUCE
SHOWER/STORM CHANCES DOWN TO AROUND 10 PERCENT. EVEN THO WEAK
IMPULSE ALOFT IS APPROACHING IN CYCLONIC NW FLOW ALOFT...THERE
JUST SEEMS TO BE NO INSTABILITY OR OVERALL MOISTURE TO WORK
WITH...ESP BELOW 8000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR
SPRINKLE HERE AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN
100 J/KG THIS AFTN...SO THUNDER CHCS LOOK PRACTICALLY NIL NEAR TAF
SITES. WILL GO WITH ONLY VFR MID CLOUDS FROM TIME TO TIME. WINDS
WILL LIGHT IN DAYTIME...CALM AT NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 303 PM CDT SUN AUG 19 2012
VERY DRY AIR WILL REMAIN IN PLACE FOR THE FIRST HALF OF THE
UPCOMING WEEKS. IN FACT...SOME LOCATIONS MAY SEE RELATIVE
HUMIDITIES DIP TO NEAR 20 PERCENT BY TUESDAY. IN ADDITION...10
HOUR FUEL MOISTURES HAVE NOW FALLEN BACK INTO THE 6 TO 10 PERCENT
RANGE. THUS...THE RISK OF RAPID WILDFIRE GROWTH WILL BE ELEVATED
DURING THIS TIME FRAME. WINDS...BOTH AT THE SURFACE AND ALOFT...
SHOULD REMAIN GENERALLY LIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MEFFERT
SHORT TERM...MEFFERT
LONG TERM....RST
AVIATION...MEFFERT
FIRE WEATHER...MEFFERT
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1143 AM CDT SUN AUG 19 2012
.UPDATE...
ISSUED AT 1104 AM CDT SUN AUG 19 2012
BASED UPON THE LATEST RADAR/STLT/NAM AND RUC PROGGED SOUNDINGS FOR
THE REST OF TODAY...AM INCLINED TO REDUCE SHOWER/STORM CHANCES
DOWN TO AROUND 10 PERCENT. EVEN THO WEAK IMPULSE ALOFT IS
APPROACHING IN CYCLONIC NW FLOW..THERE JUST SEEMS TO BE NO
INSTABILITY OR OVERALL MOISTURE TO WORK WITH /ESP BELOW 8000 FT/.
CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLE HERE AND THERE...BUT
CAPES PROGGED TO REMAIN LESS THAN 100 J/KG THIS AFTN...SO THUNDER
CHCS LOOK PRACTICALLY NIL.
ALSO...UPDATED THE AVIATION SECTION BELOW FOR THE UPCOMING 18Z
TAF FORECAST.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 1104 AM CDT SUN AUG 19 2012
BASED GENERALLY ON SAME REASONING AS IN THE UPDATE SECTION ABOVE...
AM INCLINED TO REDUCE SHOWER/STORM CHANCES DOWN TO AROUND 10
PERCENT FOR MONDAY/TUE ALSO. AGAIN...EVEN THO WEAK IMPULSES ALOFT
WILL CONTINUE TO ROTATE SSE WITHIN FAIRLY DEEP TROF /CYCLONIC FLOW/
OVER THE OHIO VALLEY...THERE JUST SEEMS TO BE VERY LITTLE
INSTABILITY AND OVERALL MOISTURE TO WORK WITH///ESP IN THE LOWEST
7000 TO 10000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR SPRINKLES HERE
AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN 400 J/KG FOR THE
MOST PART THROUGH TUE...SO THUNDER CHCS CONTINUE TO LOOK PRACTICALLY
NIL.
AS FAR AS TEMPS ARE CONCERNED...WILL CONT TO IGNORE THE OBVIOUSLY
COLD MAV TEMP BIAS. EVEN THE MET MOS TEMPS SEEM TO BE RUNNING A
FEW DEGREES TOO COOL TODAY. HOWEVER...GIVEN THE FACT THAT THERE
MAY BE MORE IN THE WAY OF MID CLOUDS MONDAY...WILL STAY CLOSE TO
THE MET MOS NUMBERS TONIGHT THROUGH TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 142 AM CDT SUN AUG 19 2012
THERE CONTINUES TO BE A GOOD DEAL OF INCONSISTENCY BETWEEN THE
MODELS IN THE EXTENDED WITH REGARDS TO HOW THEY HANDLE THE UPPER
LEVEL PATTERN. BY 12Z WEDNESDAY...THE 00Z GFS SHOWS A DEPARTING
TROUGH WITH A UPPER RIDGE DEVELOPING OVER THE NEXT FEW DAYS. THE
ECWMF CONTINUES TO ADVERTISE A CLOSED LOW DEVELOPING OVER ARKANSAS
WHICH MOVES EAST ON WEDNESDAY TOWARD NORTHERN MS/AL...AND RIDGING
ALOFT TRIES TO TAKE PLACE ON THURSDAY.
WHILE THE MATTER OF PRECIPITATION IS MOOT BECAUSE OF THE LACK OF
MOISTURE...THE MAIN CHALLENGES FOR WED-FRI WILL BE
TEMPERATURES/WIND. THE GFS AND THE GFS ENSEMBLE MEAN INDICATES HIGH
PRESSURE AT THE SFC ON WEDNESDAY WHICH MOVES EAST ON WEDNESDAY NIGHT
AND THURSDAY...AND THAT IS WHEN OUR WARM UP BEGINS. THE ECMWF SHOWS
THE SFC HIGH ALREADY TO OUR EAST ON WEDNESDAY AND AS SUCH...HAS
THINGS HEATING UP QUICKER DUE TO A QUICKER SHIFT TO WEAK SOUTHERLY
FLOW. WILL STICK WITH MID 80S FOR WEDNESDAY AND CONTINUE TO SHOW THE
INCREASE IN THE HEAT THROUGH THE END OF THE WEEK.
THE GFS AND ECMWF ARE IN FAIRLY GOOD AGREEMENT WITH BRINGING AN
UPPER LEVEL TROUGH TOWARD THE AREA ON FRIDAY...AND BRINGING
PRECIPITATION INTO THE AREA BY FRIDAY NIGHT WHICH LINGERS INTO
SATURDAY. NOT SURE HOW THE TIMING AND ACTUAL COVERAGE OF
PRECIPITATION WILL WORK OUT AT THIS POINT...BUT THE END OF THE WEEK
AND INTO THE WEEKEND LOOKS UNSETTLED AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1104 AM CDT SUN AUG 19 2012
BASED UPON THE LATEST RADAR/STLT/NAM AND RUC PROGGED SOUNDINGS FOR
THE REST OF TODAY THROUGH EARLY AFTN MON...AM INCLINED TO REDUCE
SHOWER/STORM CHANCES DOWN TO AROUND 10 PERCENT. EVEN THO WEAK
IMPULSE ALOFT IS APPROACHING IN CYCLONIC NW FLOW ALOFT...THERE
JUST SEEMS TO BE NO INSTABILITY OR OVERALL MOISTURE TO WORK
WITH...ESP BELOW 8000 FT. CANNOT RULE OUT AN ISOLD SHOWER OR
SPRINKLE HERE AND THERE...BUT CAPES PROGGED TO REMAIN LESS THAN
100 J/KG THIS AFTN...SO THUNDER CHCS LOOK PRACTICALLY NIL. WILL GO
WITH ONLY VFR MID CLOUDS FROM TIME TO TIME. WINDS WILL VERY LIGHT
NRLY IN DAYTIME...CALM AT NIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MEFFERT
SHORT TERM...MEFFERT
AVIATION...MEFFERT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1244 PM EDT SUN AUG 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE STATE TODAY WHILE A COLD FRONT
BECOMES NEARLY STATIONARY OVER THE GULF OF MAINE. THE NEXT LOW
PRESSURE SYSTEM WILL MOVE ACROSS THE REGION MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1245 PM UPDATE...HIGH PRESSURE WILL LINGER OVER THE REGION TODAY,
KEEPING LOTS OF SUNSHINE AROUND MUCH OF THE AREA. THE EXCEPTION
WILL BE COASTAL WASHINGTON COUNTY, WHERE CLOUDS ASSOCIATED WITH A
COLD FRONT JUST OFF THE COAST WILL REMAIN THROUGH MUCH OF THE DAY.
THE PREVIOUS FORECAST HAS THIS COVERED, SO ONLY MINOR ADJUSTMENTS
WERE MADE.
PREVIOUS DISCUSSION...A FRONTAL SYSTEM OFF THE DOWNEAST COAST
WILL DRIFT SLOWLY TO THE EAST OVER THE NEXT 24 HOURS AS WEAK HIGH
PRESSURE BUILDS IN FROM THE WEST. PRIMARY TASK IS TIMING OF EXIT
OF PRECIPITATION FROM DOWNEAST COAST. FOR POP GRIDS UNTIL 1200Z
WILL INITIALIZE WITH RUC13 WITH SOME MANUAL ADJUSTMENT THEN
TRANSITION TO A BLEND OF THE NAM12...GFS40...SREF AND ECMWF TO
INITIALIZE POP GRIDS. HAVE USED A BLEND OF THE NAM12 AND GMOS FOR
WINDS GRIDS. GMOS WAS USED FOR TEMPERATURE AND DEW POINT AND WILL
DECREASE MINIMUM TEMPERATURE TONIGHT WITH SEASONABLY COOL AIR MASS
IN PLACE. QPF GRIDS GENERATED WITH A BLEND OF THE
NAM80...SREF....GFS AND ECMWF.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE MAIN FOCUS WILL BE ON TUESDAY IN REGARDS TO AN APPROACHING
COLD FRONT FROM THE WEST AND LOW PRES MOVING ACROSS THE SOUTHERN
GULF OF MAINE.
MONDAY LOOKS TO BE A DRY AND PLEASANT DAY FOR THE MOST PART W/THE
EXCEPTION FOR A WEAK DISTURBANCE MOVING ACROSS THE REGION IN THE
AFTERNOON. THIS FEATURE COULD DELIVER A QUICK SHOWER TO THE WEST
AND NORTHWEST AREAS. ALL THE SHORT RANGE GUIDANCE INCLUDING THE
00Z ECMWF SHOWS SOME FORCING IN THE MID AND UPPER LEVELS BUT THE
BIGGEST INGREDIENT LACKING IS THE DEEP MOISTURE. THEREFORE, STAYED
W/20-30% POPS IN THE AFOREMENTIONED AREAS. ACCEPTED THE DAYCREW`S
MAXES OF UPPER 70S TO AROUND 80.
ANOTHER S/WV IN CONJUNCTION W/A WEAK COLD FRONT IS SHOWN BY THE
ECMWF/GFS AND CANADIAN GLOBAL TO MOVE ACROSS THE REGION BY TUESDAY
AFTERNOON. THE LATEST RUNS INCLUDING THE NAM HAVE BACKED OFF ON
PRECIP CHANCES AND AVAILABLE MOISTURE KEEPING THE PASSAGE DRY FOR
THE MOST PART. THE NAM IS THE MOST AGGRESSIVE W/THE MOISTURE AND
INSTABILITY WHILE THE GFS SHOWS MORE STABILITY. ATTM, THE DECISION
WAS TO KEEP IN LINE W/THE DAYCREW`S THINKING AND CONTINUE W/30-40%
POPS MAINLY ACROSS THE NORTH AND CENTRAL AREAS. TSTMS WERE ADDED
FOR TUESDAY AFTERNOON TAKING A BLEND OF THE NAM AND GFS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE WEAK COLD FRONT WILL SLIDE TO THE EAST TUESDAY NIGHT FOLLOWED
BY HIGH PRES FOR WEDNESDAY KEEPING CONDITIONS ON THE DRY AND
PLEASANT SIDE. HUNG ONTO THE DAYCREW`S MAX TEMPERATURES FOR
WEDNESDAY W/READINGS MAXING OUT IN THE LOW TO MID 70S.
THE 00Z RUN OF THE ECMWF AND GFS SHOW ANOTHER FRONTAL BOUNDARY
MOVING INTO THE CWA ON THURSDAY. SOME MID LEVEL FORCING IN THERE
BUT ONCE AGAIN DEEP MOISTURE IS LIMITED. THEREFORE, DECIDED ON
20-30% FOR THURSDAY AFTERNOON W/THE HIGHEST PERCENTAGES ACROSS THE
NORTHERN PART OF THE CWA. ATTM, KEPT THE MENTION OF THUNDER OUT OF
THE FCST AND WENT W/JUST SHOWERS. THE GFS QUICKLY MOVES THIS
FRONTAL BOUNDARY OFF TO THE EAST AND DRIES THINGS OUT FOR FRIDAY
WHILE THE LATEST RUN OF THE ECMWF KEEPS THE FRONT BACK LONGER AND
HAS ANOTHER AREA OF PRECIP SHOWING UP BY EARLY FRIDAY. THIS IS A
DIFFERENT SCENARIO THAN THE 12Z RUN WHICH WAS CLOSER TO THE 00Z
RUN OF THE GFS. THE 00Z RUN OF THE CANADIAN GLOBAL IS IN LINE
W/THE ECWMF. LOOKING AT THE SYNOPTIC PATTERN OF THE LONG WAVE TROF
HANGING ON ACROSS THE NE AND NO SIGNIFICANT MOISTURE AVAILABLE,
THINKING HERE IS THAT THE ECMWF AND CANADIAN COULD BE OVERDONE
W/THEIR QPF. THE DECISION WAS TO GO W/A DRY FCST FOR FRIDAY W/MAX
TEMPERATURES OF LOW TO MID 70S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: VFR CONDITIONS EXPECTED NEXT 24 HOURS. SOME IFR/MVFR
KBHB EARLY THIS MORNING DUE TO CEILING.
SHORT TERM: SHOULD BE VFR PRETTY MUCH THROUGH THE PERIOD. A BRIEF
PERIOD OF MVFR CONDITIONS COULD BE SEEN ON TUESDAY W/THE PASSAGE
OF THE COLD FRONT.
&&
.MARINE...
NEAR TERM: HAVE USED A 50/50 BLEND OF THE NAM12 AND GFS40 TO
INITIALIZE GRIDS THEN LOWER WIND SPEED BY 20 PERCENT. FOR WAVES:
HAVE USE THE NAM/SWAN TO POPULATE GRIDS. PRIMARY SOURCE OF WAVES
IS 1 TO 2 FOOT LONGER PERIOD SWELL. BASED ON WNA SPECTRAL THIS
WAVE GROUP FROM SOUTHEAST AT 9 TO 11 SECONDS.
SHORT TERM: NO HEADLINES ANTICIPATED. THE MAIN FOCUS WILL BE THE
SE SWELL DEVELOPING AND HANGING ON THROUGH THE PERIOD. SUSTAINED
WINDS OF 10 KTS AND A SEA/SWELL STATE OF 2-3 FT W/A PERIOD OF 8-9
SECONDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...HASTINGS/MIGNONE
MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1008 AM EDT SUN AUG 19 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE STATE TODAY WHILE A COLD FRONT
BECOMES NEARLY STATIONARY OVER THE GULF OF MAINE. THE NEXT LOW
PRESSURE SYSTEM WILL MOVE ACROSS THE REGION MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1005 AM UPDATE...HIGH PRESSURE WILL LINGER OVER THE REGION
TODAY, KEEPING LOTS OF SUNSHINE AROUND MUCH OF THE AREA. THE
EXCEPTION WILL BE COASTAL WASHINGTON COUNTY, WHERE CLOUDS
ASSOCIATED WITH A COLD FRONT JUST OFF THE COAST WILL REMAIN
THROUGH MUCH OF THE DAY. WE`RE ALSO SEEING SOME LIGHT RETURNS ON
RADAR NEAR EASPORT, SO HAVE ADDED MENTION OF SOME ISOLATED SHOWERS
TO TODAY`S FORECAST. ELSEWHERE, STARTING TO SEE SOME CUMULUS POP
UP ON SATELLITE SO HAVE ADJUSTED THE FORECAST TO MOSTLY SUNNY IN
MOST AREAS. NO OTHER CHANGES NEEDED WITH THIS UPDATE.
PREVIOUS DISCUSSION...A FRONTAL SYSTEM OFF THE DOWNEAST COAST
WILL DRIFT SLOWLY TO THE EAST OVER THE NEXT 24 HOURS AS WEAK HIGH
PRESSURE BUILDS IN FROM THE WEST. PRIMARY TASK IS TIMING OF EXIT
OF PRECIPITATION FROM DOWNEAST COAST. FOR POP GRIDS UNTIL 1200Z
WILL INITIALIZE WITH RUC13 WITH SOME MANUAL ADJUSTMENT THEN
TRANSITION TO A BLEND OF THE NAM12...GFS40...SREF AND ECMWF TO
INITIALIZE POP GRIDS. HAVE USED A BLEND OF THE NAM12 AND GMOS FOR
WINDS GRIDS. GMOS WAS USED FOR TEMPERATURE AND DEW POINT AND WILL
DECREASE MINIMUM TEMPERATURE TONIGHT WITH SEASONABLY COOL AIR MASS
IN PLACE. QPF GRIDS GENERATED WITH A BLEND OF THE
NAM80...SREF....GFS AND ECMWF.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
THE MAIN FOCUS WILL BE ON TUESDAY IN REGARDS TO AN APPROACHING
COLD FRONT FROM THE WEST AND LOW PRES MOVING ACROSS THE SOUTHERN
GULF OF MAINE.
MONDAY LOOKS TO BE A DRY AND PLEASANT DAY FOR THE MOST PART W/THE
EXCEPTION FOR A WEAK DISTURBANCE MOVING ACROSS THE REGION IN THE
AFTERNOON. THIS FEATURE COULD DELIVER A QUICK SHOWER TO THE WEST
AND NORTHWEST AREAS. ALL THE SHORT RANGE GUIDANCE INCLUDING THE
00Z ECMWF SHOWS SOME FORCING IN THE MID AND UPPER LEVELS BUT THE
BIGGEST INGREDIENT LACKING IS THE DEEP MOISTURE. THEREFORE, STAYED
W/20-30% POPS IN THE AFOREMENTIONED AREAS. ACCEPTED THE DAYCREW`S
MAXES OF UPPER 70S TO AROUND 80.
ANOTHER S/WV IN CONJUNCTION W/A WEAK COLD FRONT IS SHOWN BY THE
ECMWF/GFS AND CANADIAN GLOBAL TO MOVE ACROSS THE REGION BY TUESDAY
AFTERNOON. THE LATEST RUNS INCLUDING THE NAM HAVE BACKED OFF ON
PRECIP CHANCES AND AVAILABLE MOISTURE KEEPING THE PASSAGE DRY FOR
THE MOST PART. THE NAM IS THE MOST AGGRESSIVE W/THE MOISTURE AND
INSTABILITY WHILE THE GFS SHOWS MORE STABILITY. ATTM, THE DECISION
WAS TO KEEP IN LINE W/THE DAYCREW`S THINKING AND CONTINUE W/30-40%
POPS MAINLY ACROSS THE NORTH AND CENTRAL AREAS. TSTMS WERE ADDED
FOR TUESDAY AFTERNOON TAKING A BLEND OF THE NAM AND GFS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE WEAK COLD FRONT WILL SLIDE TO THE EAST TUESDAY NIGHT FOLLOWED
BY HIGH PRES FOR WEDNESDAY KEEPING CONDITIONS ON THE DRY AND
PLEASANT SIDE. HUNG ONTO THE DAYCREW`S MAX TEMPERATURES FOR
WEDNESDAY W/READINGS MAXING OUT IN THE LOW TO MID 70S.
THE 00Z RUN OF THE ECMWF AND GFS SHOW ANOTHER FRONTAL BOUNDARY
MOVING INTO THE CWA ON THURSDAY. SOME MID LEVEL FORCING IN THERE
BUT ONCE AGAIN DEEP MOISTURE IS LIMITED. THEREFORE, DECIDED ON
20-30% FOR THURSDAY AFTERNOON W/THE HIGHEST PERCENTAGES ACROSS THE
NORTHERN PART OF THE CWA. ATTM, KEPT THE MENTION OF THUNDER OUT OF
THE FCST AND WENT W/JUST SHOWERS. THE GFS QUICKLY MOVES THIS
FRONTAL BOUNDARY OFF TO THE EAST AND DRIES THINGS OUT FOR FRIDAY
WHILE THE LATEST RUN OF THE ECMWF KEEPS THE FRONT BACK LONGER AND
HAS ANOTHER AREA OF PRECIP SHOWING UP BY EARLY FRIDAY. THIS IS A
DIFFERENT SCENARIO THAN THE 12Z RUN WHICH WAS CLOSER TO THE 00Z
RUN OF THE GFS. THE 00Z RUN OF THE CANADIAN GLOBAL IS IN LINE
W/THE ECWMF. LOOKING AT THE SYNOPTIC PATTERN OF THE LONG WAVE TROF
HANGING ON ACROSS THE NE AND NO SIGNIFICANT MOISTURE AVAILABLE,
THINKING HERE IS THAT THE ECMWF AND CANADIAN COULD BE OVERDONE
W/THEIR QPF. THE DECISION WAS TO GO W/A DRY FCST FOR FRIDAY W/MAX
TEMPERATURES OF LOW TO MID 70S.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR CONDITIONS EXPECTED NEXT 24 HOURS. SOME IFR/MVFR
KBHB EARLY THIS MORNING DUE TO CEILING.
SHORT TERM: SHOULD BE VFR PRETTY MUCH THROUGH THE PERIOD. A BRIEF
PERIOD OF MVFR CONDITIONS COULD BE SEEN ON TUESDAY W/THE PASSAGE
OF THE COLD FRONT.
&&
.MARINE...
NEAR TERM: HAVE USED A 50/50 BLEND OF THE NAM12 AND GFS40 TO
INITIALIZE GRIDS THEN LOWER WIND SPEED BY 20 PERCENT. FOR WAVES:
HAVE USE THE NAM/SWAN TO POPULATE GRIDS. PRIMARY SOURCE OF WAVES
IS 1 TO 2 FOOT LONGER PERIOD SWELL. BASED ON WNA SPECTRAL THIS
WAVE GROUP FROM SOUTHEAST AT 9 TO 11 SECONDS.
SHORT TERM: NO HEADLINES ANTICIPATED. THE MAIN FOCUS WILL BE THE
SE SWELL DEVELOPING AND HANGING ON THROUGH THE PERIOD. SUSTAINED
WINDS OF 10 KTS AND A SEA/SWELL STATE OF 2-3 FT W/A PERIOD OF 8-9
SECONDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...HASTINGS/MIGNONE
MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1044 PM EDT MON AUG 20 2012
.SYNOPSIS...
AFTER ANOTHER DAY WITH A SLIGHT CHANCE FOR THUNDERSTORMS ON
TUESDAY, EXPECT DRY WEATHER AND NEAR NORMAL TEMPERATURES FOR
WEDNESDAY INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
03Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADJUST
POP AND SKY GRIDS TO ACCOUNT FOR THE LATEST TRENDS AS CONVECTION
COMES TO AN END. IN ADDITION, MORNING SHOWER CHANCES HAVE BEEN
HAVE BEEN MADE EARLIER BY A FEW HOURS ACROSS EASTERN OHIO.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD TROUGH
EXTENDING ACROSS THE OHIO VALLEY. THE AXIS OF THIS TROUGH EXTENDS
FROM ONTARIO SOUTHWEST ACROSS MICHIGAN AND INTO ILLINOIS. A PAIR
OF WEAK SHORT WAVES ARE MOVING NORTHEASTWARD OF THE AREA WITH
REMAINING CONVECTION CONFINED TO THE SOUTHEASTERN RIDGES.
OVERNIGHT...HRRR/WRF-NMM SUPPORT A RESPITE IN SHOWERS ACROSS THE
AREA BETWEEN 03Z AND 10Z. THE LOSS OF HEATING IN COMBINATION WITH
FORCING FROM THE MID-LEVEL SHORT WAVES EXITING EASTWARD SUPPORT
THIS SOLUTION AND THUS THE FORECAST IS DRY THROUGH MUCH OF THE
OVERNIGHT. SCHC POPS RETURN AROUND 10Z IN EASTERN OHIO AS THE NEXT
WAVE APPROACHES FROM THE WEST. THE MAIN WEATHER IMPACT OVERNIGHT,
HOWEVER, WILL BE FOG DEVELOPING, GENERALLY AFTER 06Z. WITH
GROUNDS IN SOME AREAS THAT ARE SATURATED FROM RECENT RAINFALL
COUPLED WITH CLEARING SKIES AND CALM WINDS, THIS WILL SUPPORT
RADIATION FOG. DENSE FOG HAS BEEN HIGHLIGHTED IN THE FORECAST FOR
THE RIVER VALLEYS AND THE EASTERN RIDGES. RADIATIONAL COOLING WILL
ALLOW FOR ANOTHER COOL NIGHT. LOWS ARE CLOSE TO LAMP GUIDANCE,
RANGING FROM THE LOWER TO MID 50S ACROSS THE AREA.
UPPER LEVEL TROUGH AXIS WILL SHIFT SOUTH INTO LOWER MICHIGAN AND
INDIANA BY TUESDAY MORNING. AS THE AXIS PUSHES EAST...TROUGH WILL
BEGIN TO FILL IN AND WEAKEN. WITH WANING SUPPORT...HAVE ONLY
INCLUDED EASTERN OHIO IN CHANCE POPS TOMORROW...KEEPING ALL OTHER
LOCATIONS UNDER SLIGHT CHANCE POPS...WHICH STILL MAY BE OVERDONE.
WITH SLIGHTLY LESS CLOUD COVER...HIGH TEMPERATURES TOMORROW SHOULD
BE A COUPLE OF DEGREES WARMER THAN TODAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
UPPER LEVEL TROUGH WILL BE OVER THE AREA ON WEDNESDAY AND MOVING
EAST ON THURSDAY. WITH A RETURN TO ZONAL FLOW...CONDITIONS ARE
EXPECTED TO BE DRY WEDNESDAY AND THURSDAY. SOME MOISTURE MAY TRY TO
SLIDE UP ALONG THE RIDGES WEDNESDAY AFTERNOON...BUT DO NOT HAVE
ENOUGH CONFIDENCE IN THIS TO INCLUDE A CHANCE FOR SHOWERS AT THIS
TIME. WINDS WILL BE LIGHT AND VARIABLE...AND HIGH TEMPERATURES
SHOULD RETURN TO THE 80S FOR NEARLY ALL LOCATIONS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. THE MODEL OUTPUT HAS BEEN TRENDING TO SHOW A
WEAK-LOOKING UPPER LEVEL TROUGH MOVING EASTBOUND ALONG THE CANADIAN
BORDER THIS WEEKEND, THAT MAY AFFECT THE UPPER OHIO VALLEY MONDAY OR
TUESDAY.
SO AT THIS JUNCTURE, CONTINUE TO EXPECT DRY CONDITIONS ACROSS THE
UPPER OHIO VALLEY THROUGH SUNDAY IF NOT MONDAY.
DUE TO THE RELATIVE LACK OF CLOUDS THIS PERIOD, CONTINUE TO EXPECT
EACH DAY TO HAVE A LARGER THAN NORMAL DIURNAL TEMPERATURE RANGE.
SO CONCUR WITH HPC THINKING...WITH SUPPORT FROM RECENT GFS AND ECMWF
MOS AND NAEFS MEDIAN VALUES...THAT LOWS FRIDAY CAN BE UP TO 5
DEGREES COOLER THAN NORMAL...WHILE HIGHS FRIDAY WILL BE NEAR OR
SLIGHTLY WARMER THAN NORMAL.
WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR NORMAL VALUES
THIS WEEKEND...EXPECT LOWS THIS WEEKEND AND MONDAY TO BE CLOSE TO
NORMAL...WHILE HIGHS CAN BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS CONTINUE ACROSS THE FORECAST AREA THIS EVENING BUT
THE SHOWERS ARE DIMINISHING IN BOTH COVERAGE AND INTENSITY. GENERAL
VFR CONDITIONS WILL CONTINUE INTO THE EARLY MORNING HOURS AS
SHOWERS CONTINUE TO WEAKEN.
HAVE ADDED A PERIOD OF IFR FOG EARLY TUESDAY MORNING, 07Z-12Z. WITH
SHOWERS ENDING IN THE EARLY MORNING...EXPECT SOME RADIATIONAL COOLING
TO RESULT IN FOG FORMATION TOWARD DAYBREAK. AFTER FOG BURNS OFF
TUESDAY MORNING, EXPECT NONSTOP VFR THE REST OF DAYTIME TUESDAY.
.OUTLOOK/ TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY VFR, EXCEPT FOR RESTRICTIONS DUE TO EARLY MORNING RIVER
VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
806 PM EDT MON AUG 20 2012
.SYNOPSIS...
AFTER ANOTHER DAY WITH A SLIGHT CHANCE FOR THUNDERSTORMS ON
TUESDAY, EXPECT DRY WEATHER AND NEAR NORMAL TEMPERATURES FOR
WEDNESDAY INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
00Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADJUST
POP AND SKY GRIDS TO ACCOUNT FOR THE LATEST TRENDS AS CONVECTION
AND CLOUD COVERAGE DIMINISHES. OTHERWISE, LITTLE CHANGE TO THE
OVERNIGHT FORECAST.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD TROUGH
EXTENDING ACROSS THE OHIO VALLEY. THE AXIS OF THIS TROUGH EXTENDS
FROM ONTARIO SOUTHWEST ACROSS MICHIGAN AND INTO ILLINOIS. A PAIR
OF WEAK SHORT WAVES ARE MOVING EASTWARD ACROSS WESTERN PA AND WV
WITH ISOLATED CONVECTION BEGINNING TO DIMINISH THIS EVENING.
TONIGHT...HRRR/WRF-NMM SUPPORT A RESPITE IN SHOWERS ACROSS THE
AREA BETWEEN 03Z AND 12Z. THE LOSS OF HEATING IN COMBINATION WITH
FORCING FROM THE MID-LEVEL SHORT WAVES EXITING EASTWARD SUPPORT
THIS SOLUTION AND THUS THE FORECAST IS DRY THROUGH MUCH OF THE
OVERNIGHT. MAIN WEATHER IMPACT OVERNIGHT WILL BE FOG DEVELOPING,
GENERALLY AFTER 06Z. WITH GROUNDS IN SOME AREAS THAT ARE SATURATED
FROM RECENT RAINFALL COUPLED WITH CLEARING SKIES AND CALM WINDS,
THIS WILL SUPPORT RADIATION FOG. DENSE FOG HAS BEEN HIGHLIGHTED IN
THE FORECAST FOR THE RIVER VALLEYS AND THE EASTERN RIDGES.
UPPER LEVEL TROUGH AXIS WILL SHIFT SOUTH INTO LOWER MICHIGAN AND
INDIANA BY TUESDAY MORNING. AS THE AXIS PUSHES EAST...TROUGH WILL
BEGIN TO FILL IN AND WEAKEN. WITH WANING SUPPORT...HAVE ONLY
INCLUDED EASTERN OHIO IN CHANCE POPS TOMORROW...KEEPING ALL OTHER
LOCATIONS UNDER SLIGHT CHANCE POPS...WHICH STILL MAY BE OVERDONE.
WITH SLIGHTLY LESS CLOUD COVER...HIGH TEMPERATURES TOMORROW SHOULD
BE A COUPLE OF DEGREES WARMER THAN TODAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
UPPER LEVEL TROUGH WILL BE OVER THE AREA ON WEDNESDAY AND MOVING
EAST ON THURSDAY. WITH A RETURN TO ZONAL FLOW...CONDITIONS ARE
EXPECTED TO BE DRY WEDNESDAY AND THURSDAY. SOME MOISTURE MAY TRY TO
SLIDE UP ALONG THE RIDGES WEDNESDAY AFTERNOON...BUT DO NOT HAVE
ENOUGH CONFIDENCE IN THIS TO INCLUDE A CHANCE FOR SHOWERS AT THIS
TIME. WINDS WILL BE LIGHT AND VARIABLE...AND HIGH TEMPERATURES
SHOULD RETURN TO THE 80S FOR NEARLY ALL LOCATIONS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. THE MODEL OUTPUT HAS BEEN TRENDING TO SHOW A
WEAK-LOOKING UPPER LEVEL TROUGH MOVING EASTBOUND ALONG THE CANADIAN
BORDER THIS WEEKEND, THAT MAY AFFECT THE UPPER OHIO VALLEY MONDAY OR
TUESDAY.
SO AT THIS JUNCTURE, CONTINUE TO EXPECT DRY CONDITIONS ACROSS THE
UPPER OHIO VALLEY THROUGH SUNDAY IF NOT MONDAY.
DUE TO THE RELATIVE LACK OF CLOUDS THIS PERIOD, CONTINUE TO EXPECT
EACH DAY TO HAVE A LARGER THAN NORMAL DIURNAL TEMPERATURE RANGE.
SO CONCUR WITH HPC THINKING...WITH SUPPORT FROM RECENT GFS AND ECMWF
MOS AND NAEFS MEDIAN VALUES...THAT LOWS FRIDAY CAN BE UP TO 5
DEGREES COOLER THAN NORMAL...WHILE HIGHS FRIDAY WILL BE NEAR OR
SLIGHTLY WARMER THAN NORMAL.
WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR NORMAL VALUES
THIS WEEKEND...EXPECT LOWS THIS WEEKEND AND MONDAY TO BE CLOSE TO
NORMAL...WHILE HIGHS CAN BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS CONTINUE ACROSS THE FORECAST AREA THIS EVENING BUT
THE SHOWERS ARE DIMINISHING IN BOTH COVERAGE AND INTENSITY. GENERAL
VFR CONDITIONS WILL CONTINUE INTO THE EARLY MORNING HOURS AS
SHOWERS CONTINUE TO WEAKEN.
HAVE ADDED A PERIOD OF IFR FOG EARLY TUESDAY MORNING, 07Z-12Z. WITH
SHOWERS ENDING IN THE EARLY MORNING...EXPECT SOME RADIATIONAL COOLING
TO RESULT IN FOG FORMATION TOWARD DAYBREAK. AFTER FOG BURNS OFF
TUESDAY MORNING, EXPECT NONSTOP VFR THE REST OF DAYTIME TUESDAY.
.OUTLOOK/ TUESDAY NIGHT THROUGH SATURDAY/...
GENERALLY VFR, EXCEPT FOR RESTRICTIONS DUE TO EARLY MORNING RIVER
VALLEY FOG.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
322 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS. HIGH PRESSURE WILL MOVE INTO THE AREA
ON WEDNESDAY, RETURNING DRY WEATHER FOR THE MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH AXIS
EXTENDING FROM THE JAMES BAY IN CANADA ACROSS THE GREAT LAKES AND
INTO ILLINOIS. THIS LEAVES THE OHIO UPPER VALLEY IN A
SOUTHWESTERLY FLOW ON THE EASTERN SIDE OF THE BROAD BASE OF THE
TROUGH. SHOWERS HAVE COME TO AN END ACROSS THE SOUTHEAST RIDGES AS
THE INITIAL SHORT WAVE HAS MOVED OUT OF THE AREA. VORT ENERGY
ACROSS NORTHERN OHIO IS NOW BEGINNING TO INITIATE CONVECTION
THERE. THE LATEST LAPS ANALYSIS INDICATES WEAK CAPE BTW 300-800
J/KG AND SPC RAP MESOSCALE ANALYSIS INDICATES WEAK BULK EFFECTIVE
SHEAR AT 25KTS ACROSS THE FORECAST AREA.
THROUGH THE EARLY EVENING...THE RAP INDICATES THAT THE FOCUS OF
FORCING WITH VORT ENERGY WILL PASS NORTHWEST OF THE CWA. STILL, DAYTIME
HEATING WITH AROUND 1000 J/KG CAPE AND STEEPENING LOW- LEVEL AND
MID-LEVEL LAPSE RATES MAY BE ENOUGH FOR SCATTERED SHOWERS TO
DEVELOP. FORECAST ALSO CONSISTS OF ISOLATED THUNDERSTORMS, GIVEN
THE LACK OF FORCING AND WEAK INSTABILITY ANTICIPATED. WITH THE
LACK OF COVERAGE OF CONVECTION THIS AFTERNOON INTO THE EARLY
EVENING, ANTICIPATE ANY SHOWERS OR STORMS TO BE BRIEF AS THEY MOVE
ACROSS THE AREA. HIGH TEMPS THIS AFTERNOON ARE A BLEND OF THE LAPS
AND RECENT OBS TRENDS, WITH HIGHS RANGING FROM THE LOWER 70S
ACROSS THE EASTERN RIDGES TO THE LOWER 80S IN PORTIONS OF EASTERN
OHIO AND NORTHERN WV.
TONIGHT...WRF-NMM/HRRR HIRES MODELS SUPPORT CONVECTION DIMINISHING
FAIRLY QUICKLY AFTER 00Z. HAVE MAINTAINED SCHC POPS EARLY
OVERNIGHT AS ANY LINGERING CONVECTION SLIDES EAST OF THE AREA.
THERE IS LOW CONFIDENCE IN PATCHY FOG DEVELOPING IN THE RIVER
VALLEYS DURING THE PRE-DAWN HOURS AS THIS WILL BE DEPENDENT ON HOW
MUCH RAINFALL LOCALITIES RECEIVE TODAY. THUS, HAVE LEFT FOG OUT OF
THE PUBLIC FORECAST AT THIS TIME. OVERNIGHT TEMPS ARE CLOSER TO
THE COOLER MAV GUIDANCE WITH LOWS RANGING FROM THE LOW TO MID 50S
ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THERE IS ECMWF/GFS/NAM AGREEMENT THAT THE BROAD MID-LEVEL TROUGH
WILL REMAIN ACROSS THE OHIO VALLEY ON MONDAY AND AMPLIFY AS ITS
AXIS SWINGS INTO THE UPPER OHIO VALLEY LATE TUESDAY INTO
WEDNESDAY. WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW
AHEAD OF THIS FEATURE AND THE MAJORITY OF MODEL SOLUTIONS SHOWING
WEAK INSTABILITY EACH DAY, CHC POPS WITH SCHC THUNDER IS FORECAST
FOR MONDAY WITH SCHC POPS/THUNDER ON TUESDAY. TEMPS WILL BE AROUND
5 DEGREES BELOW NORMAL THROUGH THIS PERIOD.
A MODEL CONSENSUS INDICATES THE TROUGH SLIDING EAST OF AREA AND
HIGH PRESSURE BUILDING IN FROM THE WEST ON WEDNESDAY. THIS WILL
ALLOW FOR A DRY FORECAST WITH MORE ABUNDANT SUNSHINE ON WEDNESDAY.
WITH INCREASED SUNSHINE TEMPS WILL WARM CLOSER TO SEASONAL NORMALS
ACROSS THE AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUDFREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON.
RECENT GFS LAMP AND NAM MOS CONTINUE TO SUPPORT THE IDEA OF AN IFR
RIVER VALLEY FOG EPISODE 07Z-13Z, THAT MAY AFFECT NEARBY TAF SITES.
HOWEVER, AT THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES. DID MENTION IFR VISIBILITIES AT
KMGW, KHLG, AND KLBE, WHERE SURFACE DEW POINTS THIS AFTERNOON HAVE
CLIMBED INTO THE UPPER 50S, AN INDICATION THAT LATE NIGHT LOW
TEMPERATURES COULD BE COLDER THAN UPS FOG TECHNIQUE CROSSOVER
VALUES.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS LATE THIS AFTERNOON, AND THEIR
SUBSEQUENT EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION
CAPPED SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR. RESTRICTIONS MAY ACCOMPANY SCATTERED THUNDERSTORMS
MONDAY EVENING, AND PATCHY RIVER VALLEY FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
216 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO CHANGE
WX GRIDS WORDING TO COVERAGE WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS POSSIBLE THIS AFTERNOON.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH AXIS
EXTENDING FROM THE JAMES BAY IN CANADA ACROSS THE GREAT LAKES AND
INTO ILLINOIS. THIS LEAVES THE OHIO UPPER VALLEY IN A SOUTHWESTERLY
FLOW ON THE EASTERN SIDE OF THE BROAD BASE OF THE TROUGH. SHOWERS
HAVE COME TO AN END ACROSS THE SOUTHEAST RIDGES AS THE INITIAL
SHORT WAVE HAS MOVED OUT OF THE AREA. VORT ENERGY ACROSS NORTHERN
OHIO IS NOW BEGINNING TO INITIATE CONVECTION THERE. THE LATEST
LAPS ANALYSIS INDICATES WEAK CAPE BTW 300-800 J/KG AND SPC RAP
MESOSCALE ANALYSIS INDICATES WEAK BULK EFFECTIVE SHEAR AT 25KTS
ACROSS THE FORECAST AREA.
THIS AFTERNOON INTO THE EARLY EVENING...ALTHOUGH THE RAP INDICATES
THAT THE FOCUS OF FORCING WITH VORT ENERGY WILL PASS NORTHWEST OF
THE CWA, DAYTIME HEATING WITH AROUND 1000 J/KG CAPE AND STEEPENING
LOW-LEVEL AND MID-LEVEL LAPSE RATES SHOULD BE ENOUGH FOR
SCATTERED SHOWERS TO DEVELOP. FORECAST ALSO CONSISTS OF ISOLATED
THUNDERSTORMS, GIVEN THE LACK OF FORCING AND WEAK INSTABILITY
ANTICIPATED. WITH THE LACK OF COVERAGE OF CONVECTION THIS
AFTERNOON INTO THE EARLY EVENING, ANTICIPATE ANY SHOWERS OR STORMS
TO BE BRIEF AS THEY MOVE ACROSS THE AREA. HIGH TEMPS THIS
AFTERNOON ARE A BLEND OF THE LAPS AND RECENT OBS TRENDS, WITH
HIGHS RANGING FROM THE LOWER 70S ACROSS THE EASTERN RIDGES TO THE
LOWER 80S IN PORTIONS OF EASTERN OHIO AND NORTHERN WV.
TONIGHT...WRF-NMM/HRRR HIRES MODELS SUPPORT CONVECTION DIMINISHING
FAIRLY QUICKLY AFTER 00Z. HAVE MAINTAINED SCHC POPS EARLY
OVERNIGHT AS LINGERING CONVECTION SLIDES EAST OF THE AREA. THERE
IS LOW CONFIDENCE IN PATCHY FOG DEVELOPING IN THE RIVER VALLEYS
DURING THE PRE-DAWN HOURS AS THIS WILL BE DEPENDENT ON HOW MUCH
RAINFALL LOCALITIES RECEIVE TODAY. THUS, HAVE LEFT FOG OUT OF THE
FORECAST AT THIS TIME. OVERNIGHT TEMPS ARE CLOSER TO THE COOLER
MAV GUIDANCE WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS MUCH
OF THE AREA.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE MID-LEVEL TROUGH AXIS OF THE AFOREMENTIONED SYSTEM IS PROGGED
TO LINGER WEST 0F...OR OVER THE UPPER OHIO AREA THROUGH MID WEEK.
HOWEVER...GRADUAL DRYING AND STRENGTHENING OF SURFACE HIGH
PRESSURE NORTH OF THE OHIO WL FURTHER LIMIT PRECIP CHANCES AND
SLIGHT POPS WERE SHIFTED EASTWARD ON TUESDAY AND TAPERED OFF BY
WEDNESDAY.
TEMPS UNDER THE MID/UPR TROUGH WERE FORECAST USING A GUIDANCE
BLEND AND WL REMAIN APPROXIMATELY 5 DEGREES BELOW NORMAL THROUGH
THE SHORT TERM PERIOD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT CONTINUES TO SHOW
BROAD HIGH PRESSURE UNDER WEAK FLOW ALOFT ACROSS THE EASTERN U.S.
INTO THE WEEKEND. HENCE, WILL MAINTAIN A FORECAST OF DRY AND
RELATIVELY CLOUD FREE CONDITIONS THROUGH THE PERIOD.
THIS SHOULD TRANSLATE TO EACH DAY HAVING A LARGER THAN NORMAL
DIURNAL TEMPERATURE RANGE. CONCUR WITH HPC THINKING, WITH SUPPORT
FROM GFS AND ECMWF MOS AND NAEFS MEDIAN VALUES, THAT LOWS THURSDAY
AND FRIDAY CAN BE UP TO 5 DEGREES COOLER THAN NORMAL, WHILE HIGHS BE
NEAR NORMAL. WITH POTENTIAL OF SURFACE DEW POINTS CLIMBING TO NEAR
NORMAL VALUES THIS WEEKEND, EXPECT WEEKEND LOWS TO LIKEWISE BE NEAR
NORMAL, WHILE HIGHS BE UP TO 5 DEGREES WARMER THAN NORMAL.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 07Z.
PER BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT FORESEE ONLY
POTENTIAL OF RESTRICTIONS WOULD BE WITH ISOLATED SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON.
RECENT GFS LAMP AND NAM MOS CONTINUE TO SUPPORT THE IDEA OF AN IFR
RIVER VALLEY FOG EPISODE 07Z-13Z, THAT MAY AFFECT NEARBY TAF SITES.
HOWEVER, AT THIS JUNCTURE HAD ONLY ENOUGH CONFIDENCE TO INCLUDE MVFR
VISIBILITIES FOR MOST TAF SITES. DID MENTION IFR VISIBILITIES AT
KMGW, KHLG, AND KLBE, WHERE SURFACE DEW POINTS THIS AFTERNOON HAVE
CLIMBED INTO THE UPPER 50S, AN INDICATION THAT LATE NIGHT LOW
TEMPERATURES COULD BE COLDER THAN UPS FOG TECHNIQUE CROSSOVER
VALUES.
THE OTHER KEY TO FOG DEVELOPMENT LATE TONIGHT WOULD BE THE
LOCATION AND EXTENT OF SHOWERS LATE THIS AFTERNOON, AND THEIR
SUBSEQUENT EFFECT ON MOISTENING A SHALLOW TEMPERATURE-INVERSION
CAPPED SURFACE LAYER TONIGHT.
EXPECT THE REST OF MONDAY TO BE MAINLY VFR, ALTHOUGH AGAIN CANNOT
COMPLETELY RULE OUT THE POTENTIAL OF A BRIEF RESTRICTION WITH
ISOLATED AFTERNOON THUNDERSTORMS.
.OUTLOOK/ MONDAY NIGHT THROUGH FRIDAY/...
GENERALLY VFR. RESTRICTIONS MAY ACCOMPANY SCATTERED THUNDERSTORMS
MONDAY EVENING, AND PATCHY RIVER VALLEY FOG EACH MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
150 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL LOW PRESSURE DISTURBANCES WILL CROSS
THE UPPER OHIO VALLEY EARLY THIS WEEK AND GENERATE A FEW SHOWERS
AND POSSIBLY THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO CHANGE
WX GRIDS WORDING TO COVERAGE WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS POSSIBLE THIS AFTERNOON.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH AXIS
EXTENDING FROM THE JAMES BAY IN CANADA ACROSS THE GREAT LAKES AND
INTO ILLINOIS. THIS LEAVES THE OHIO UPPER VALLEY IN A SOUTHWESTERLY
FLOW ON THE EASTERN SIDE OF THE BROAD BASE OF THE TROUGH. SHOWERS
HAVE COME TO AN END ACROSS THE SOUTHEAST RIDGES AS THE INITIAL
SHORT WAVE HAS MOVED OUT OF THE AREA. VORT ENERGY ACROSS NORTHERN
OHIO IS NOW BEGINNING TO INITIATE CONVECTION THERE. THE LATEST
LAPS ANALYSIS INDICATES WEAK CAPE BTW 300-800 J/KG AND SPC RAP
MESOSCALE ANALYSIS INDICATES WEAK BULK EFFECTIVE SHEAR AT 25KTS
ACROSS THE FORECAST AREA.
THIS AFTERNOON INTO THE EARLY EVENING...ALTHOUGH THE RAP INDICATES
THAT THE FOCUS OF FORCING WITH VORT ENERGY WILL PASS NORTHWEST OF
THE CWA, DAYTIME HEATING WITH AROUND 1000 J/KG CAPE AND STEEPENING
LOW-LEVEL AND MID-LEVEL LAPSE RATES SHOULD BE ENOUGH FOR
SCATTERED SHOWERS TO DEVELOP. FORECAST ALSO CONSISTS OF ISOLATED
THUNDERSTORMS, GIVEN THE LACK OF FORCING AND WEAK INSTABILITY
ANTICIPATED. WITH THE LACK OF COVERAGE OF CONVECTION THIS
AFTERNOON INTO THE EARLY EVENING, ANTICIPATE ANY SHOWERS OR STORMS
TO BE BRIEF AS THEY MOVE ACROSS THE AREA. HIGH TEMPS THIS
AFTERNOON ARE A BLEND OF THE LAPS AND RECENT OBS TRENDS, WITH
HIGHS RANGING FROM THE LOWER 70S ACROSS THE EASTERN RIDGES TO THE
LOWER 80S IN PORTIONS OF EASTERN OHIO AND NORTHERN WV.
TONIGHT...WRF-NMM/HRRR HIRES MODELS SUPPORT CONVECTION DIMINISHING
FAIRLY QUICKLY AFTER 00Z. HAVE MAINTAINED SCHC POPS EARLY
OVERNIGHT AS LINGERING CONVECTION SLIDES EAST OF THE AREA. THERE
IS LOW CONFIDENCE IN PATCHY FOG DEVELOPING IN THE RIVER VALLEYS
DURING THE PRE-DAWN HOURS AS THIS WILL BE DEPENDENT ON HOW MUCH
RAINFALL LOCALITIES RECEIVE TODAY. THUS, HAVE LEFT FOG OUT OF THE
FORECAST AT THIS TIME. OVERNIGHT TEMPS ARE CLOSER TO THE COOLER
MAV GUIDANCE WITH LOWS RANGING FROM THE LOW TO MID 50S ACROSS MUCH
OF THE AREA.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE MID-LEVEL TROUGH AXIS OF THE AFOREMENTIONED SYSTEM IS PROGGED
TO LINGER WEST 0F...OR OVER THE UPPER OHIO AREA THROUGH MID WEEK.
HOWEVER...GRADUAL DRYING AND STRENGTHENING OF SURFACE HIGH
PRESSURE NORTH OF THE OHIO WL FURTHER LIMIT PRECIP CHANCES AND
SLIGHT POPS WERE SHIFTED EASTWARD ON TUESDAY AND TAPERED OFF BY
WEDNESDAY.
TEMPS UNDER THE MID/UPR TROUGH WERE FORECAST USING A GUIDANCE
BLEND AND WL REMAIN APPROXIMATELY 5 DEGREES BELOW NORMAL THROUGH
THE SHORT TERM PERIOD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CONSENSUS OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOW BROAD HIGH
PRESSURE ACROSS THE EASTERN U.S. WILL MAINTAIN DRY CONDITIONS
THROUGH FRIDAY IF NOT SATURDAY.
BLEND OF GFS MOS, ECMWF MOS, AND NAEFS MEDIAN VALUES SHOW
TEMPERATURES WEDNESDAY CAN STILL BE SLIGHTLY COOLER THAN NORMAL. AS
HIGH PRESSURE CENTER TRANSITIONS TO THE EAST COAST, DAYTIME HIGH
TEMPERATURES WILL BECOME SLIGHTLY WARMER THAN NORMAL THURSDAY INTO
WEEKEND.
BY SATURDAY, LOW LEVEL SOUTHERLY WINDS WILL TRANSPORT SURFACE DEW
POINTS OF 60 TO 65 INTO THE UPPER OHIO VALLEY. SO EARLY MORNING LOW
TEMPERATURES SHOULD RETURN TO NEAR NORMAL VALUES THIS WEEKEND.
CONCUR WITH HPC THINKING THAT THERE CAN BE AT LEAST A SLIGHT CHANCE
OF SHOWERS BY SUNDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR ACROSS THE UPPER OHIO VALLEY THROUGH 08Z
MONDAY. CANNOT COMPLETELY RULE OUT RESTRICTIONS AS SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE POSSIBLE LATE THIS
AFTERNOON.
PER RECENT GFS LAMP AND NAM MOS, THERE IS POTENTIAL FOR AN IFR
RIVER VALLEY FOG EPISODE 08Z-13Z MONDAY. SO FAR HAVE SUFFICIENT
CONFIDENCE TO FORECAST MVFR VISIBILITIES AT NEARBY TAF SITES. THE
DEGREE OF EARLY MORNING FOG WILL ALSO DEPEND EXTENT OF RAINFALL
THIS AFTERNOON AND LATER RADIATIONAL COOLING RESULTING FROM
DECREASE IN CLOUDS TONIGHT.
.OUTLOOK/ SUNDAY NIGHT THROUGH THURSDAY/...
GENERALLY VFR. RESTRICTIONS MAY ACCOMPANY SCATTERED THUNDERSTORMS
MONDAY AFTERNOON AND EVENING AND PATCHY RIVER VALLEY FOG EACH
MORNING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1017 AM EDT SUN AUG 19 2012
.SYNOPSIS...
HIGH PRESSURE WAS LOCATED OVER NEW YORK STATE TODAY...WHILE A
FRONTAL BOUNDARY WAS STALLED OUT SOUTH OF THE AREA. SURFACE LOW
PRESSURE WILL DEVELOP OVER THE CAROLINA PIEDMONT THIS AFTERNOON
AND MOVE NORTHEAST TO THE MID ATLANTIC COAST TONIGHT. HIGH
PRESSURE WILL SLOWLY BUILD OVER THE REGION DURING THE MIDDLE
PORTION OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FRONTAL BOUNDARY WAS LOCATED TO THE SOUTH ACROSS NORTH CAROLINA
THIS MORNING...WHILE WEAK SURFACE HIGH PRESSURE WAS POSITIONED
OVER NEW YORK STATE. CWA WAS LOCATED IN A TRANSITION
ZONE...CHARACTERIZED BY INCREASING MOISTURE IN THE WAKE OF
YESTERDAY/S DRYING. WARM ADVECTION WAS UNDERWAY WELL NORTH OF THE
FRONTAL BOUNDARY...AND MODELS ALSO INDICATE ISENTROPIC LIFT
STRENGTHENING OVER THE CWA THROUGH THE DAY AND INTO THE NIGHT. LIFT
WILL LIKELY BE ENHANCED BY A MID-LEVEL WAVE OVER THE SOUTHERN
APPALACHIANS THAT MOVES EAST/NORTHEAST WITH TIME.
RESULT OF THESE FEATURES HAS BEEN FOR AN AREA OF SHOWERS TO MOVE
INTO THE POTOMAC HIGHLANDS/CENTRAL SHENANDOAH VALLEY EARLY THIS
MORNING. 12Z NAM THROUGH H24 IS COMING IN LINE...AND AGREES WITH
RECENT RUNS OF THE HRRR AND WRF-ARW. THESE MODELS SUGGEST SHOWERS
EXPANDING NORTHEAST THROUGH THE CWA THROUGH THE DAYTIME HOURS. 06Z
GFS IS NOT AS AGGRESSIVE THIS FAR NORTH BUT SUSPECT 12Z WILL ALSO
FOLLOW SUIT WITH THE NAM. POPS HAVE ALREADY BEEN INCREASED ACROSS
THE CWA...WITH TIMING DETAIL ALSO ADDED. ELEVATED INSTABILITY
COULD ALSO RESULT IN ISOLATED THUNDERSTORMS ESPECIALLY OVER THE
SOUTHERN PORTION OF THE CWA.
ANOTHER WAVE MAY KEEP CHANCES OF SHOWERS GOING WELL INTO THE
OVERNIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
EXPECT PRECIP COVERAGE TO CONTRACT SOUTHWARD THIS EVENING AS THE SFC
LOW DEVELOPS AND BRINGS NELY FLOW IN FROM NJ. CHANCES OF CONTINUING
PRECIP OVER ZONES SOUTHEAST OF DC...BUT AGAIN THE COVERAGE AND
INTENSITY OF RAINFALL DEPENDS ON THE LOW TRACK. MIN TEMPS NEAR
NORMAL WITH NLY FLOW AND CLOUDS...MID TO UPR 50S WEST OF THE BLUE
RIDGE...LOW TO MID 60S EAST.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
LAST NGT I WROTE ABT THE DIFFERENCES IN THE MDL DEPICTION OF
MON..W/ THE NAM HAVG LOW POPS AND THE GFS HIGH. ONCE AGN THE MDLS
HV FLIPPED REGARDING POPS...W/ THE NAM BCMG THE HIGHER MDL -
FORMING A DEEPENING LOW PRES ALONG THE DELMARVA MON MRNG MUCH LK
IT WAS DOING TWO NGTS AGO. WL KEEP POPS IN THE LKLY RANGE MON FM
ABT 20 MILES W OF I-95 INTO THE BAY...CHC W OF THAT LN. ISOLD TSTMS
PSBL BUT NOT XPCTG A WIDESPREAD SVR OUTBRK. GIVEN LACK OF RAIN
LATELY AND TRANSITORY NATURE OF THE LOW DO NOT FEEL FLDG WL BE A PROBLEM.
THERE WL BE AN UPR TROF OVR THE RGN MON...LIFTING N ON TUE. THIS
WL ALLOW SF HIGH PRES TO BLD INTO THE RGN...GIVING THE MID ATLC A
DEFINITE LATE SUMMER FEEL. XPCT TO SEE PLNTY OF SUNSHINE...
ESPECIALLY WED-FRI...W/ DAYTIME HIGHS IN THE MU80S AND DWPTS IN
THE U50S/L60S. LOWS WL RANGE FM THE U50S IN THE HIGHLANDS TO THE
U60S IN THE CITIES AND ALONG THE BAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
SHOWERS ARE EXPECTED TO OVERSPREAD THE AREA FROM SOUTHWEST TO
NORTHEAST THROUGH THE DAY. SHOWERS HAVE ALREADY MADE IT TO
CHO...AND CHO MAY BE REDUCED TO IFR AT TIMES. CONFIDENCE IS LOW
FOR IFR AT REMAINING SITES...BUT A PERIOD OF MVFR VSBYS SEEMS
LIKELY THIS AFTERNOON. SECONDARY WAVE MAY KEEP SHOWERS GOING WELL
INTO THE NIGHT.
AT LEAST MVFR CIGS PSBL MON AT ALL THREE MAJOR AIRPORTS. FOG PSBL
MON NGT...THEN VFR CONDS MOST OF THE WK.
&&
.MARINE...
WEDGE OF HIGH PRESSURE CONTINUES LIGHT NELY/ELY FLOW OVER THE WATERS
THIS MORNING. LOW PRESSURE DEVELOPS OVER CNTRL NC/SC THIS
AFTERNOON...CROSSING SOUTH OF THE MD PORTION OF THE BAY LATE
TONIGHT. SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT BEGINNING
TONIGHT FOR MOST OF THE WATERS FOR NELY FLOW GUSTING TO AROUND 20
KT ON THE NORTH SIDE OF THE LOW.
JUST LK DURG THE PAST 2 NGTS...THERE IS DISCREPANCY AMONGST THE
MDLS REGARDING THE DVLPMNT AND POSN OF A SFC LOW TO FORM IN ASSO
W/ THE UPPER TROF SUN NGT AND MON. WHERE IT TRACKS WL DETERMINE
HOW MUCH PCPN WL FALL OVER THE WATERS...AND ALSO HOW STRONG THE
WINDS WL BE. WE`VE ISSUED A SMALL CRAFT ADVSRY PARTLY BECAUSE THE
NAM BUFKIT SNDG FOR NHK IS QUITE STRONG.
THERE IS THE PSBLTY THAT A SECONDARY LOW COLD FORM ON TUE B4 HIGH
PRES BLDS IN FOR MUCH OF THE REST OF THE WK...BUT THIS IS NOT FOR CERTAIN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 2 PM EDT MONDAY FOR ANZ531-
532-539-540.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 2 PM EDT MONDAY
FOR ANZ533-534-536-537-541>543.
&&
$$
BPP/BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
333 PM EDT SUN AUG 19 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 19 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
ERN NAMERICA AND ARND CLOSED UPR LO NEAR JAMES BAY DOWNSTREAM OF UPR
RDG OVER THE ROCKIES. RUC ANALYSIS INDICATES A SHRTWV EMBEDDED
WITHIN THE UPR TROF IS OVER LK SUP. THIS DISTURBANCE/HINT OF SFC LO
PRES TROF SUPPORTED SOME SCT -SHRA MAINLY OVER CNTRL UPR MI INTO
EARLY AFTN. BUT DESPITE SOME SFC HEATING...THERE ARE NO MORE THAN
ISOLD -SHRA NOW OVER THE SCNTRL DESPITE SOME LK BREEZE CNVGC IN THAT
AREA. LLVL DRY AIR APPEARS TO BE THE MAIN LIMITING FACTOR AS SFC
DEWPTS HAVE MIXED OUT TO 40 TO 45 AT MOST SPOTS. ANOTHER STRONGER
DISTURBANCE ROTATING ARND THE PARENT UPR LO IS NOTED ON WV IMAGERY
OVER NRN ONTARIO. WHERE THE MSTR IS DEEPEST ON THE CYC SIDE OF THIS
FEATURE...THICK CLD COVER IS PRESENT OVER MUCH OF ONTARIO EXCEPT THE
FAR W. MUCH DRIER AIRMASS SHOWN ON THE 12Z INL/YPL RAOBS...WHERE
PWAT IS 0.38/0.41 INCH RESPECTIVELY OR NEAR 50 PCT OF NORMAL...IS
ALLOWING CLR-PCLDY CONDITIONS FM NRN MN THRU MOST OF WRN ONTARIO.
BUT THERE IS ANOTHER PATCH OF CLDS OVER FAR NW ONTARIO/ADJOINING
MANITOBA ASSOCIATED WITH YET ANOTHER SHRTWV DIVING SSEWD E OF LK
WINNIPEG WITHIN THE NNW FLOW ALF.
TONIGHT...EXPECT ANY LINGERING -SHRA OVER MAINLY THE SCNTRL TO END
THIS EVNG WITH EXIT OF SHRTWV NOW OVER LK SUP AND LOSS OF DAYTIME
HEATING. ALTHOUGH THE EVNG WL THEN TURN MOCLR EXCEPT FOR SOME PATCHY
HI CLDS WITH DRY AIR SHOWN ON THE 12Z INL/YPL RAOBS DOMINATING...
BULK OF GUIDANCE INDICATES SHRTWV NOW DIVING SWD THRU NRN ONTARIO WL
DIVE SWD TO NEAR ISLE ROYALE BY 12Z MON. SO EVEN THOUGH ALL MODELS
SHOW BULK OF THICKER CLD NOW DOMINATING MUCH OF ONTARIO ON THE CYC
SIDE OF SHRTWV TRACK WL REMAIN TO THE NE OF THE CWA UNDER LOWER H85
TEMPS...SUSPECT MORE CLDS WL ARRIVE OVER AT LEAST THE NRN TIER LATER
TNGT. WITH A PERIOD OF MOCLR SKIES THRU AT LEAST THE EVNG INTO EARLY
OVERNGT...EXPECT A QUICK DROP OF TEMPS. THE COOLEST OVERNGT MINS
INTO THE UPR 30S ARE MOST LIKELY OVER THE SRN TIER...WHERE MORE CLDS
ASSOCIATED WITH INCOMING SHRTWV ARE LIKELY NOT TO ARRIVE BEFORE
SUNRISE.
MON...INCOMING SHRTWV IS PROGGED TO SLIDE SWD ACRS WRN UPR MI AND
INTO WI IN THE AFTN. SINCE THE CWA WL BE ON THE CYC SIDE OF THE
TRACK OF THIS DISTURBANCE AND ACCOMPANYING DPVA/SOME DEEP LYR
QVECTOR CNVGC WL OCCUR DURING PEAK HEATING TIME...EXPECT AT LEAST
ISOLD -SHRA TO IMPACT MAINLY THE SCNTRL...WHERE SOME LK BREEZE CNVGC
MIGHT ENHANCE PCPN POTENTIAL. POPS WL BE LIMITED BY LLVL DRY AIR AND
LO KINX FCST NO HIER THAN 25 TO 30. WITH H85 TEMPS FCST IN THE 7 TO
9C RANGE...EXPECT HI TEMPS TO PEAK NOT FAR FM 70.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 19 2012
OVERALL GOOD MODEL AGREEMENT THROUGH WED...LEADING TO INCREASED
FORECAST CONFIDENCE FOR THIS TIME PERIOD.
STARTING THE PERIOD 00Z TUE...A SHORTWAVE TROUGH WILL BE EXITING THE
WA TO THE SE...ROTATING AROUND THE UPPER LEVEL LOW OVER NW QUEBEC
AND THE UPPER TROUGH OVER MUCH OF THE ERN HALF OF THE CONUS. THERE
MAY BE SOME SHOWERS EARLY ON MON NIGHT FROM THIS PASSING
THROUGH...BUT COVERAGE SHOULD BE LIMITED DUE TO THE DRY AIRMASS
OVERHEAD. WEAK UPPER RIDGING QUICKLY MOVES IN BEHIND THE
SHORTWAVE...EXTENDING FROM A RIDGE OVER THE WRN CONUS.
MODELS DO NOT SHOW ANY WAVES MOVING THROUGH ON TUE...BUT GIVEN NW
FLOW ALOFT IT IS HARD TO COMPLETELY RULE OUT AFTERNOON PRECIP...BUT
FOR NOW WILL LEAVE PRECIP OUT OF THE FORECAST. WITH ONLY SCATTERED
CU FOR CLOUDS...850MB TEMPS AOA 12MB SHOULD LEAD TO HIGH TEMPS IN
THE MID TO UPPER 70S...WITH A FEW LOW 80S POSSIBLE.
A WEAK SHORTWAVE TROUGH IS THEN SET TO MOVE NEAR THE CWA WED...ALSO
BRINGING A COLD FRONT INTO THE AREA. LIMITED MOISTURE AND
UNCERTAINTY REGARDING THE STRENGTH AND TRACK OF THE SHORTWAVE HAS
LEAD TO LIMITED CONFIDENCE WITH THIS SYSTEM...SO KEPT PRECIP CHANCES
ON THE LOW SIDE. HIGH TEMPS SHOULD BE SIMILAR TO TUE.
FOR WED NIGHT THROUGH NEXT SUN...MODELS SHOW THE COLD FRONT FROM WED/WED
NIGHT STALLING OVER OR NEAR THE CWA THU THROUGH FRI UNTIL AN
UPPER/SFC TROUGH MOVE THROUGH FRI NIGHT AND SAT. MODELS ALSO SHOW A
STRONGER UPPER LOW MOVING ACROSS SRN CANADA STARTING WED
NIGHT...THEN MOVING TO MANITOBA BY 00Z NEXT MON. WHEREAS THE 00Z/19
GFS AND 00Z/19 ECMWF AGREE PRETTY WELL ON THE LARGE SCALE
PATTERN...THE ECMWF HAS HAD VERY POOR RUN TO RUN CONTINUITY. THE GFS
ON THE OTHER HAND HAS SHOWN FAIRLY GOOD RUN TO RUN
CONTINUITY...LEADING TO MORE CONFIDENCE IN THE GFS SOLUTION BUT LOW
FORECAST CONFIDENCE OVERALL FOR THU ON. DID NOT SPEND TOO MUCH TIME
ON THIS PART OF THE FORECAST GIVEN LIMITED CONFIDENCE...AND SINCE
CONSENSUS OF MODEL DATA /WHICH FAVORS THE GFS/ LOOKED
REASONABLE...SO JUST USED THAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 136 PM EDT SUN AUG 19 2012
ALTHOUGH DISTURBANCES ROTATING ARND DEEP CLOSED LO NEAR JAMES BAY
WILL BRING PERIODS OF CLDS TO UPR MI THIS FCST PERIOD...EXPECT VFR
CONDITIONS TO PREVAIL WITH RELATIVELY DRY NEAR SFC LYR. ALTHOUGH
THERE COULD BE SOME FOG MAINLY AT SAW/IWD TNGT WITH LIGHT WINDS
UNDER WEAK SFC HI PRES RDG...NO FOG WAS OBSVD UPSTREAM LAST NGT
WITHIN DRY AIRMASS DEPICTED ON THE 12Z INL/YPL RAOBS. SO KEPT A
MENTION OF FOG OUT OF TAFS FOR NOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 19 2012
EXPECT WINDS NO HIER THAN 20 KTS THRU THU WITH WEAK PRES GRADIENT
DOMINATING THE UPPER GREAT LAKES. SINCE HI PRES WILL DOMINATE MOST
OF THE TIME UNTIL LATER IN THE WEEK...THERE WILL BE LITTLE THREAT OF
PRECIPITATION UNTIL THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT SUN AUG 19 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 507 AM EDT SUN AUG 19 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP TROF DOMINATING THE
ERN CONUS. TROF CONTINUES TO BE ANCHORED BY A MID/UPPER LEVEL
CYCLONE CENTERED IN THE VCNTY OF JAMES BAY...AND THE UPPER LAKES ARE
FIRMLY UNDER THE INFLUENCE OF THE TROF. ALTHOUGH SHORTWAVE AND
ASSOCIATED COLD FRONT PASSED YESTERDAY AFTN/EVENING...VARYING
AMOUNTS OF CLOUD COVER LINGER OVER UPPER MI EARLY THIS MORNING. OCNL
CLOUD COVER IS PROBABLY PREVENTING A MORE WIDESPREAD OR DENSE FOG
FROM DEVELOPING AS SEVERAL SITES HAVE HAD WIDELY FLUCTUATING VIS
DURING THE NIGHT.
WITH UPPER MI REMAINING FIRMLY UNDER THE INFLUENCE OF THE MID/UPPER
TROF TODAY AND TONIGHT...MAIN FCST ISSUE IS WHETHER ANY PCPN WILL
OCCUR. IN SUMMERTIME NW FLOW...EVEN THE SUBTLEST OF WAVES CAN
TRIGGER ISOLD/SCT CONVECTION. WHILE THERE ARE NO OBVIOUS SHORTWAVES
EVIDENT UPSTREAM IN NRN ONTARIO...THERE ARE HINTS OF ONE JUST N OF
LAKE SUPERIOR THAT IS ANALYZED BY THE LATEST RUC. THAT SUBTLE WAVE
IS PROBABLY RESPONSIBLE FOR THE RECENT EXPANSION OF CLOUDS OVER THE
FCST AREA AS WELL AS THE ISOLD SHRA THAT HAVE DEVELOPED FROM
ONTONAGON COUNTY N TO JUST OFFSHORE OF THE KEWEENAW PENINSULA. ONE
ASPECT THAT WILL BE WORKING AGAINST CONVECTION TODAY WILL BE THE
DRIER AIR MASS EVIDENT UPSTREAM IN NRN ONTARIO PER 00Z CWPL
SOUNDING. AS AN INDICATION OF THE DRIER AIR...THE K INDEX WAS 3. A
NICE SWATH OF CLEAR SKIES WAS ALSO EVIDENT ACROSS NRN ONTARIO TO THE
NW OF LAKE SUPERIOR YESTERDAY AFTN...AND SFC DWPTS WERE DOWN INTO
THE 30S IN THAT AREA. HOWEVER...WITH AFORMENTIONED SUBTLE WAVE
DRIFTING S...DEVELOPMENT OF LAKE BREEZE CONVERGENCE ZONE BTWN LAKE
SUPERIOR AND LAKE MI AND WITH MODELS DELAYING ARRIVAL OF THE DRIER
AIR UPSTREAM...A MENTION OF AT LEAST ISOLD SHRA APPEARS WARRANTED
FROM ROUGHLY NEAR KIMT E TO S OF KERY IN THE LAKE BREEZE CONVERGENCE
ZONE THIS AFTN. WILL ALSO NEED TO MONITOR TRENDS OVER THE NEXT FEW
HRS TO SEE IF CURRENT EXPANDING CLOUD COVER IS A PRECURSOR TO
MORNING SHRA DEVELOPMENT OVER A LARGER PORTION OF THE FCST AREA.
ANY SHRA NEAR LAKE MI WILL END EARLY THIS EVENING AS SHORTWAVE SLIPS
TO THE S. OTHERWISE...IT SHOULD BE A DRY NIGHT THOUGH THERE ARE
HINTS THAT ANOTHER WAVE MAY BE DROPPING INTO THE AREA OVERNIGHT.
WILL BE SOMETHING TO MONITOR FOR POSSIBLY ADDING SLIGHT CHC/ISOLD
SHRA IN LATER FCSTS. POTENTIAL CLOUD COVER WITH WEAK WAVE MAKES FOR
A CHALLENGING MIN TEMP FCST TONIGHT. AT THIS TIME...IT APPEARS CLOUD
COVER SHOULD BE LIMITED ENOUGH FOR AT LEAST THE FIRST PART OF THE
NIGHT TO FAVOR THE LOWER END OF AVBL GUIDANCE. SOME UPPER 30S WILL
BE POSSIBLE IN TRADITIONAL INTERIOR COLD SPOTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 507 AM EDT SUN AUG 19 2012
GENERAL AGREEMENT IS PRESENT IN OVERALL UPPER AIR PATTERN THROUGH
THE UPCOMING WEEK. DEEP TROUGH OVER MOST OF EASTERN CANADA INTO THE
EASTERN CONUS /INCLUDING GREAT LAKES/ DE-AMPLIFIES BY WEDNESDAY. BY
THE MID-LATE WEEK...TROUGH OVER WESTERN CANADA INTO PACIFIC NORTHWEST
EJECTS A PIECE OF ENERGY INTO THE NORTHERN PLAINS. WHERE THAT WEAKER
TROUGH PROGRESSES IS A QUESTION AND WILL HAVE IMPACT ON FORECAST OVER
UPPER GREAT LAKES THURSDAY AND FRIDAY. FAIR TO SAY THAT AGREEMENT
FROM THE GFS/ECMWF/GEM-NHEM IS BETTER TO START THE WEEK THAN TO END
THE WEEK. MAIN ISSUE AT END OF WEEK IS HOW FAR EAST ENERGY OVER THE
NORTHERN PLAINS WILL MOVE INTO THE GREAT LAKES. GFS CONTINUES TO BE
DEEPER AND FARTHER EAST...RESULTING IN GOOD CHANCE OF PRECIPITATION
ON FRIDAY OVER UPPER MICHIGAN. ECWMF/EXTRAPOLATION OF GEM-NHEM WOULD
KEEP MAJORITY OF FORCING AND PRECIPITATION WITH THE WEAKER TROUGH
SOUTHWEST OF UPPER MICHIGAN INTO THE UPPER MISSISSIPPI RIVER VALLEY.
TO START THE LONG TERM...HAVE A SMALL SHOT AT ISOLD SHRA ON MONDAY
OVER CENTRAL CWA IN THE MID-LATE AFTERNOON AS LAST OF STRONGER
SHORTWAVES DROP SOUTH ON WESTERN PERIFERY OF LARGER SCALE UPPER
TROUGH. FORECAST SOUNDINGS FROM GFS AND NAM INDICATE MOISTURE OVER
THE CWA ONLY FOCUSES BETWEEN 800MB AND 700MB. DRY AIR BELOW LCL
IS QUITE DRY AS DAY BEGINS WITH DEWPOINTS IN THE 30S. PROBABLY WILL
ONLY SEE DEWPOINTS RISE INTO THE MID 40S AT BEST IN THE AFTERNOON AS
LOW-LEVEL MOISTURE ADVECTION IS LIMITED. SREF IDEA SHOWING QPF
FORMING OVER SCNTRL CWA AFTER 18Z IS LIKELY ON TRACK. COVERAGE OF ANY
SHRA WILL BE VERY ISOLATED DUE TO DRY LOW-LEVELS. NO TSRA INCLUDED
WITH POOR MID-LEVEL LAPSE RATES LESS THAN 6C/KM AND SBCAPE VALUES
ONLY UP TO 200 J/KG. MODELS HINT AT MID-LEVEL MOISTURE STICKING
AROUND OFF AND ON THROUGH MONDAY NIGHT BUT WITH SAME LIMITING FACTORS
AS MONDAY AFTERNOON DO NOT EXPECT MUCH IN WAY OF PRECIPITATION ON
MONDAY NIGHT.
COUPLE OF WEAKER SHORTWAVES RIPPLE THROUGH UPPER GREAT LAKES TUESDAY
BUT MOISTURE IS FORECAST TO BE EVEN SHALLOWER THAN ON MONDAY...AGAIN
CENTERED AROUND 800MB. ADDITIONAL MID-LEVEL MOISTURE COULD ROLL
ACROSS WITH SCT-BKN CLOUDS 15-20 KFT POSSIBLE. MIX OF CLOUDS AND
SUNSHINE GIVES WAY TO MORE SUNSHINE IN THE AFTERNOON...SO BASED ON
H85 TEMPS TOWARD AOA 12C EXPECT MAX TEMPS WELL INTO THE 70S FOR MOST
AREAS WITH EVEN A POTENTIAL OF SEEING SOME READINGS AROUND 80
DEGREES OVER WESTERN AND CENTRAL CWA.
LOOKING WELL TO THE NORTHWEST CURRENTLY THERE IS A PRETTY STRONG
SHORTWAVE CRESTING RIDGE OVER WESTERN CONUS INTO WESTERN CANADA.
WAVES IS OVER THE NORTHWEST TERRITORIES OF CANADA. MODELS SHOW WAVE
SPLITTING BUT ONE FORMIDABLE PIECE OF SHORTWAVE ENERGY IS FORECAST
TO DIG INTO NORTHWEST ONTARIO TUESDAY NIGHT INTO WEDNESDAY. GFS
FARTHER SOUTH WITH THE WAVE AND ASSOCIATED PRECIPITATION...BUT
ECMWF AND GEM-NHEM HAVE THE WAVE AS WELL...BUT NOT AS FAR SOUTH. NAM
APPEARS TOO FAST/WEAK WITH THE SHORTWAVE AND IS NOT PREFERRED. ALL
THE MODELS INDICATE AREA OF H85 TEMP AND H85-H7 MOISTURE ADVECTION
SETS UP JUST AHEAD OF THE WAVE AS IT DIGS TOWARD UPPER GREAT LAKES
TUESDAY NIGHT. USING BLEND OF LAST FEW GFS MODEL RUNS ALONG WITH
ECMWF/GEM-NHEM AND EVEN SOME OF THE SREF...KEPT POPS HIGHEST ON
TUESDAY NIGHT OVER NORTHERN SECTIONS OF LK SUPERIOR...AND NO REAL
POPS OVER LAND AREA OF UPPER MICHIGAN...ASIDE FROM ISLE ROYALE.
IDEA FITS SYNOPTIC PATTERN AS MOST LAND CWA WILL BE THE WITHIN THE
MORE UNFAVORABLE RIGHT EXIT REGION OF JET STREAK FOR PRECIPITATION.
KEPT SLIGHT CHANCES FOR WEDNESDAY OVER CENTRAL AND EAST AS LARGER
SCALE FORCING ALONG WITH WEAK SFC TROUGH COULD COMBINE WITH DAYTIME
HEATING TO HELP FORM SOME SHOWERS DURING THE PEAK HEATING OF THE DAY.
IN THE EXTENDED...00Z MODEL RUNS PROVIDE NO TRENDS OF NOTE ON EXTENT
OF LARGER SCALE TROUGHING OVER UPPER GREAT LAKES TO CLOSE THE WEEK.
GFS CONTINUES TO SHOVE UPPER TROUGH PUSHING INTO THE NORTHERN PLAINS
ON THURSDAY ON INTO THE UPPER GREAT LAKES ON FRIDAY. THE TROUGH ALONG
WITH INCREASING LOW-LEVEL MOISTURE ADVECTION AND PRESENCE OF SFC WARM
FRONT HELPS TO GENERATE PLENTY OF QPF FRIDAY INTO FRIDAY NIGHT. ON
THE FLIP SIDE THE LATEST ECMWF IS MORE SHUNTED TO THE SOUTHWEST WITH
THE UPPER TROUGH AND THUS BRINGS VERY LITTLE QPF INTO THE UPPER GREAT
LAKES WITH HIGH PRESSURE STAYING THE DOMINANT FEATURE. MAIN WARM
FRONT REMAINS WELL TO THE SOUTH OF CWA. LATEST CANADIAN LOOKS MORE
LIKE THE ECMWF BUT DOES TRY TO BRING SOME QPF INTO AT LEAST WESTERN
CWA ON FRIDAY. MODEL CONSENSUS INDICATES HIGHEST CHANCES FOR
PRECIPITATION FRIDAY INTO FRIDAY NIGHT...BUT THIS IS BEING BIASED
SOMEWHAT BY GFS MODEL ELEMENTS. WILL STAY WITH CONSENSUS GIVEN THE
STARK DIFFERENCES OFFERED UP BY ECMWF AND GFS...BUT CERTAINLY
POSSIBLE THAT FRIDAY MAY END UP MAINLY DRY COMPARED TO THE HIGHER
CHANCE POPS IN THIS FORECAST. DOES APPEAR THAT NEXT WEEKEND WOULD
FEATURE A DRYING TREND AS THE UPPER TROUGH DEPARTS THE AREA. TOUGH TO
GET TOO SPECIFIC ABOUT THOSE DETAILS THOUGH DUE TO THE MODEL
DIFFERENCES STILL AROUND LEADING INTO NEXT WEEKEND. TEMPERATURES
SHOULD SHOW WARMING TREND INTO NEXT WEEKEND AS H85 TEMPS STEADILY
CLIMB FROM WEDNESDAY TO SATURDAY. IF GFS IS CORRECT THOUGH...WARMING
WOULD BE TEMPERED THURSDAY AND DEFINITELY INTO FRIDAY WITH MORE
CLOUDS AND PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 136 PM EDT SUN AUG 19 2012
ALTHOUGH DISTURBANCES ROTATING ARND DEEP CLOSED LO NEAR JAMES BAY
WILL BRING PERIODS OF CLDS TO UPR MI THIS FCST PERIOD...EXPECT VFR
CONDITIONS TO PREVAIL WITH RELATIVELY DRY NEAR SFC LYR. ALTHOUGH
THERE COULD BE SOME FOG MAINLY AT SAW/IWD TNGT WITH LIGHT WINDS
UNDER WEAK SFC HI PRES RDG...NO FOG WAS OBSVD UPSTREAM LAST NGT
WITHIN DRY AIRMASS DEPICTED ON THE 12Z INL/YPL RAOBS. SO KEPT A
MENTION OF FOG OUT OF TAFS FOR NOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 AM EDT SUN AUG 19 2012
BRIEFLY TIGHTER PRESSURE GRADIENT WILL ALLOW NORTHWEST WIND GUSTS
TO REACH 20-25 KTS OVER EASTERN SECTIONS OF LK SUPERIOR THIS
AFTERNOON INTO THIS EVENING. WINDS DIMINISH OVERNIGHT TONIGHT AND
REMAIN MAINLY BELOW 20 KTS THROUGH WEDNESDAY AS HIGH PRESSURE STAYS
CLOSE BY. EXCEPTION COULD BE TUESDAY AFTERNOON AND EVENING OVER
WESTERN SECTIONS WITH SOUTHWEST WIND GUSTS PUSHING ABOVE 20 KTS IN
THE VICINITY OF ISLE ROYALE. LOW PRESSURE SYSTEM APPROACHING LATE
THIS WEEK RESULTS IN WINDS BECOMING MORE EAST TO SOUTHEAST AND
INCREASING OVER 20 KTS. WINDS MAY END UP HIGHER DEPENDING ON
ULTIMATE TRACK AND STRENGTH OF SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT SUN AUG 19 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 507 AM EDT SUN AUG 19 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP TROF DOMINATING THE
ERN CONUS. TROF CONTINUES TO BE ANCHORED BY A MID/UPPER LEVEL
CYCLONE CENTERED IN THE VCNTY OF JAMES BAY...AND THE UPPER LAKES ARE
FIRMLY UNDER THE INFLUENCE OF THE TROF. ALTHOUGH SHORTWAVE AND
ASSOCIATED COLD FRONT PASSED YESTERDAY AFTN/EVENING...VARYING
AMOUNTS OF CLOUD COVER LINGER OVER UPPER MI EARLY THIS MORNING. OCNL
CLOUD COVER IS PROBABLY PREVENTING A MORE WIDESPREAD OR DENSE FOG
FROM DEVELOPING AS SEVERAL SITES HAVE HAD WIDELY FLUCTUATING VIS
DURING THE NIGHT.
WITH UPPER MI REMAINING FIRMLY UNDER THE INFLUENCE OF THE MID/UPPER
TROF TODAY AND TONIGHT...MAIN FCST ISSUE IS WHETHER ANY PCPN WILL
OCCUR. IN SUMMERTIME NW FLOW...EVEN THE SUBTLEST OF WAVES CAN
TRIGGER ISOLD/SCT CONVECTION. WHILE THERE ARE NO OBVIOUS SHORTWAVES
EVIDENT UPSTREAM IN NRN ONTARIO...THERE ARE HINTS OF ONE JUST N OF
LAKE SUPERIOR THAT IS ANALYZED BY THE LATEST RUC. THAT SUBTLE WAVE
IS PROBABLY RESPONSIBLE FOR THE RECENT EXPANSION OF CLOUDS OVER THE
FCST AREA AS WELL AS THE ISOLD SHRA THAT HAVE DEVELOPED FROM
ONTONAGON COUNTY N TO JUST OFFSHORE OF THE KEWEENAW PENINSULA. ONE
ASPECT THAT WILL BE WORKING AGAINST CONVECTION TODAY WILL BE THE
DRIER AIR MASS EVIDENT UPSTREAM IN NRN ONTARIO PER 00Z CWPL
SOUNDING. AS AN INDICATION OF THE DRIER AIR...THE K INDEX WAS 3. A
NICE SWATH OF CLEAR SKIES WAS ALSO EVIDENT ACROSS NRN ONTARIO TO THE
NW OF LAKE SUPERIOR YESTERDAY AFTN...AND SFC DWPTS WERE DOWN INTO
THE 30S IN THAT AREA. HOWEVER...WITH AFORMENTIONED SUBTLE WAVE
DRIFTING S...DEVELOPMENT OF LAKE BREEZE CONVERGENCE ZONE BTWN LAKE
SUPERIOR AND LAKE MI AND WITH MODELS DELAYING ARRIVAL OF THE DRIER
AIR UPSTREAM...A MENTION OF AT LEAST ISOLD SHRA APPEARS WARRANTED
FROM ROUGHLY NEAR KIMT E TO S OF KERY IN THE LAKE BREEZE CONVERGENCE
ZONE THIS AFTN. WILL ALSO NEED TO MONITOR TRENDS OVER THE NEXT FEW
HRS TO SEE IF CURRENT EXPANDING CLOUD COVER IS A PRECURSOR TO
MORNING SHRA DEVELOPMENT OVER A LARGER PORTION OF THE FCST AREA.
ANY SHRA NEAR LAKE MI WILL END EARLY THIS EVENING AS SHORTWAVE SLIPS
TO THE S. OTHERWISE...IT SHOULD BE A DRY NIGHT THOUGH THERE ARE
HINTS THAT ANOTHER WAVE MAY BE DROPPING INTO THE AREA OVERNIGHT.
WILL BE SOMETHING TO MONITOR FOR POSSIBLY ADDING SLIGHT CHC/ISOLD
SHRA IN LATER FCSTS. POTENTIAL CLOUD COVER WITH WEAK WAVE MAKES FOR
A CHALLENGING MIN TEMP FCST TONIGHT. AT THIS TIME...IT APPEARS CLOUD
COVER SHOULD BE LIMITED ENOUGH FOR AT LEAST THE FIRST PART OF THE
NIGHT TO FAVOR THE LOWER END OF AVBL GUIDANCE. SOME UPPER 30S WILL
BE POSSIBLE IN TRADITIONAL INTERIOR COLD SPOTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 507 AM EDT SUN AUG 19 2012
GENERAL AGREEMENT IS PRESENT IN OVERALL UPPER AIR PATTERN THROUGH
THE UPCOMING WEEK. DEEP TROUGH OVER MOST OF EASTERN CANADA INTO THE
EASTERN CONUS /INCLUDING GREAT LAKES/ DE-AMPLIFIES BY WEDNESDAY. BY
THE MID-LATE WEEK...TROUGH OVER WESTERN CANADA INTO PACIFIC NORTHWEST
EJECTS A PIECE OF ENERGY INTO THE NORTHERN PLAINS. WHERE THAT WEAKER
TROUGH PROGRESSES IS A QUESTION AND WILL HAVE IMPACT ON FORECAST OVER
UPPER GREAT LAKES THURSDAY AND FRIDAY. FAIR TO SAY THAT AGREEMENT
FROM THE GFS/ECMWF/GEM-NHEM IS BETTER TO START THE WEEK THAN TO END
THE WEEK. MAIN ISSUE AT END OF WEEK IS HOW FAR EAST ENERGY OVER THE
NORTHERN PLAINS WILL MOVE INTO THE GREAT LAKES. GFS CONTINUES TO BE
DEEPER AND FARTHER EAST...RESULTING IN GOOD CHANCE OF PRECIPITATION
ON FRIDAY OVER UPPER MICHIGAN. ECWMF/EXTRAPOLATION OF GEM-NHEM WOULD
KEEP MAJORITY OF FORCING AND PRECIPITATION WITH THE WEAKER TROUGH
SOUTHWEST OF UPPER MICHIGAN INTO THE UPPER MISSISSIPPI RIVER VALLEY.
TO START THE LONG TERM...HAVE A SMALL SHOT AT ISOLD SHRA ON MONDAY
OVER CENTRAL CWA IN THE MID-LATE AFTERNOON AS LAST OF STRONGER
SHORTWAVES DROP SOUTH ON WESTERN PERIFERY OF LARGER SCALE UPPER
TROUGH. FORECAST SOUNDINGS FROM GFS AND NAM INDICATE MOISTURE OVER
THE CWA ONLY FOCUSES BETWEEN 800MB AND 700MB. DRY AIR BELOW LCL
IS QUITE DRY AS DAY BEGINS WITH DEWPOINTS IN THE 30S. PROBABLY WILL
ONLY SEE DEWPOINTS RISE INTO THE MID 40S AT BEST IN THE AFTERNOON AS
LOW-LEVEL MOISTURE ADVECTION IS LIMITED. SREF IDEA SHOWING QPF
FORMING OVER SCNTRL CWA AFTER 18Z IS LIKELY ON TRACK. COVERAGE OF ANY
SHRA WILL BE VERY ISOLATED DUE TO DRY LOW-LEVELS. NO TSRA INCLUDED
WITH POOR MID-LEVEL LAPSE RATES LESS THAN 6C/KM AND SBCAPE VALUES
ONLY UP TO 200 J/KG. MODELS HINT AT MID-LEVEL MOISTURE STICKING
AROUND OFF AND ON THROUGH MONDAY NIGHT BUT WITH SAME LIMITING FACTORS
AS MONDAY AFTERNOON DO NOT EXPECT MUCH IN WAY OF PRECIPITATION ON
MONDAY NIGHT.
COUPLE OF WEAKER SHORTWAVES RIPPLE THROUGH UPPER GREAT LAKES TUESDAY
BUT MOISTURE IS FORECAST TO BE EVEN SHALLOWER THAN ON MONDAY...AGAIN
CENTERED AROUND 800MB. ADDITIONAL MID-LEVEL MOISTURE COULD ROLL
ACROSS WITH SCT-BKN CLOUDS 15-20 KFT POSSIBLE. MIX OF CLOUDS AND
SUNSHINE GIVES WAY TO MORE SUNSHINE IN THE AFTERNOON...SO BASED ON
H85 TEMPS TOWARD AOA 12C EXPECT MAX TEMPS WELL INTO THE 70S FOR MOST
AREAS WITH EVEN A POTENTIAL OF SEEING SOME READINGS AROUND 80
DEGREES OVER WESTERN AND CENTRAL CWA.
LOOKING WELL TO THE NORTHWEST CURRENTLY THERE IS A PRETTY STRONG
SHORTWAVE CRESTING RIDGE OVER WESTERN CONUS INTO WESTERN CANADA.
WAVES IS OVER THE NORTHWEST TERRITORIES OF CANADA. MODELS SHOW WAVE
SPLITTING BUT ONE FORMIDABLE PIECE OF SHORTWAVE ENERGY IS FORECAST
TO DIG INTO NORTHWEST ONTARIO TUESDAY NIGHT INTO WEDNESDAY. GFS
FARTHER SOUTH WITH THE WAVE AND ASSOCIATED PRECIPITATION...BUT
ECMWF AND GEM-NHEM HAVE THE WAVE AS WELL...BUT NOT AS FAR SOUTH. NAM
APPEARS TOO FAST/WEAK WITH THE SHORTWAVE AND IS NOT PREFERRED. ALL
THE MODELS INDICATE AREA OF H85 TEMP AND H85-H7 MOISTURE ADVECTION
SETS UP JUST AHEAD OF THE WAVE AS IT DIGS TOWARD UPPER GREAT LAKES
TUESDAY NIGHT. USING BLEND OF LAST FEW GFS MODEL RUNS ALONG WITH
ECMWF/GEM-NHEM AND EVEN SOME OF THE SREF...KEPT POPS HIGHEST ON
TUESDAY NIGHT OVER NORTHERN SECTIONS OF LK SUPERIOR...AND NO REAL
POPS OVER LAND AREA OF UPPER MICHIGAN...ASIDE FROM ISLE ROYALE.
IDEA FITS SYNOPTIC PATTERN AS MOST LAND CWA WILL BE THE WITHIN THE
MORE UNFAVORABLE RIGHT EXIT REGION OF JET STREAK FOR PRECIPITATION.
KEPT SLIGHT CHANCES FOR WEDNESDAY OVER CENTRAL AND EAST AS LARGER
SCALE FORCING ALONG WITH WEAK SFC TROUGH COULD COMBINE WITH DAYTIME
HEATING TO HELP FORM SOME SHOWERS DURING THE PEAK HEATING OF THE DAY.
IN THE EXTENDED...00Z MODEL RUNS PROVIDE NO TRENDS OF NOTE ON EXTENT
OF LARGER SCALE TROUGHING OVER UPPER GREAT LAKES TO CLOSE THE WEEK.
GFS CONTINUES TO SHOVE UPPER TROUGH PUSHING INTO THE NORTHERN PLAINS
ON THURSDAY ON INTO THE UPPER GREAT LAKES ON FRIDAY. THE TROUGH ALONG
WITH INCREASING LOW-LEVEL MOISTURE ADVECTION AND PRESENCE OF SFC WARM
FRONT HELPS TO GENERATE PLENTY OF QPF FRIDAY INTO FRIDAY NIGHT. ON
THE FLIP SIDE THE LATEST ECMWF IS MORE SHUNTED TO THE SOUTHWEST WITH
THE UPPER TROUGH AND THUS BRINGS VERY LITTLE QPF INTO THE UPPER GREAT
LAKES WITH HIGH PRESSURE STAYING THE DOMINANT FEATURE. MAIN WARM
FRONT REMAINS WELL TO THE SOUTH OF CWA. LATEST CANADIAN LOOKS MORE
LIKE THE ECMWF BUT DOES TRY TO BRING SOME QPF INTO AT LEAST WESTERN
CWA ON FRIDAY. MODEL CONSENSUS INDICATES HIGHEST CHANCES FOR
PRECIPITATION FRIDAY INTO FRIDAY NIGHT...BUT THIS IS BEING BIASED
SOMEWHAT BY GFS MODEL ELEMENTS. WILL STAY WITH CONSENSUS GIVEN THE
STARK DIFFERENCES OFFERED UP BY ECMWF AND GFS...BUT CERTAINLY
POSSIBLE THAT FRIDAY MAY END UP MAINLY DRY COMPARED TO THE HIGHER
CHANCE POPS IN THIS FORECAST. DOES APPEAR THAT NEXT WEEKEND WOULD
FEATURE A DRYING TREND AS THE UPPER TROUGH DEPARTS THE AREA. TOUGH TO
GET TOO SPECIFIC ABOUT THOSE DETAILS THOUGH DUE TO THE MODEL
DIFFERENCES STILL AROUND LEADING INTO NEXT WEEKEND. TEMPERATURES
SHOULD SHOW WARMING TREND INTO NEXT WEEKEND AS H85 TEMPS STEADILY
CLIMB FROM WEDNESDAY TO SATURDAY. IF GFS IS CORRECT THOUGH...WARMING
WOULD BE TEMPERED THURSDAY AND DEFINITELY INTO FRIDAY WITH MORE
CLOUDS AND PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 738 AM EDT SUN AUG 19 2012
ANOTHER DISTURBANCE DROPPING INTO THE UPPER LAKES IS GENERATING A
FEW -SHRA IN NW UPPER MI ATTM. BASED ON MOVEMENT...THE -SHRA MAY
AFFECT KSAW FOR AN HOUR OR TWO THIS MORNING. IT IS ANTICIPATED
CONDITIONS WILL REMAIN VFR IF A -SHRA DOES OCCUR. PCPN IS NOT
EXPECTED AT KCMX/KIWD. OTHERWISE...OTHER THAN SOME FOG AT KIWD WHICH
WILL DISSIPATE IN THE NEXT HR OR SO...VFR CONDITIONS WILL PREVAIL AT
KIWD/KCMX/KSAW THRU THIS FCST PERIOD. HOWEVER...WILL NEED TO WATCH
FOR POSSIBLE FOG DEVELOPMENT TONIGHT AT KIWD/KSAW...BUT MAINLY AT
KIWD AS THAT SITE HAS BEEN PRONE TO SHALLOW FOG AND WIDELY
FLUCTUATING VIS ON A NIGHTLY BASIS RECENTLY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 AM EDT SUN AUG 19 2012
BRIEFLY TIGHTER PRESSURE GRADIENT WILL ALLOW NORTHWEST WIND GUSTS
TO REACH 20-25 KTS OVER EASTERN SECTIONS OF LK SUPERIOR THIS
AFTERNOON INTO THIS EVENING. WINDS DIMINISH OVERNIGHT TONIGHT AND
REMAIN MAINLY BELOW 20 KTS THROUGH WEDNESDAY AS HIGH PRESSURE STAYS
CLOSE BY. EXCEPTION COULD BE TUESDAY AFTERNOON AND EVENING OVER
WESTERN SECTIONS WITH SOUTHWEST WIND GUSTS PUSHING ABOVE 20 KTS IN
THE VICINITY OF ISLE ROYALE. LOW PRESSURE SYSTEM APPROACHING LATE
THIS WEEK RESULTS IN WINDS BECOMING MORE EAST TO SOUTHEAST AND
INCREASING OVER 20 KTS. WINDS MAY END UP HIGHER DEPENDING ON
ULTIMATE TRACK AND STRENGTH OF SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
511 AM EDT SUN AUG 19 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 507 AM EDT SUN AUG 19 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP TROF DOMINATING THE
ERN CONUS. TROF CONTINUES TO BE ANCHORED BY A MID/UPPER LEVEL
CYCLONE CENTERED IN THE VCNTY OF JAMES BAY...AND THE UPPER LAKES ARE
FIRMLY UNDER THE INFLUENCE OF THE TROF. ALTHOUGH SHORTWAVE AND
ASSOCIATED COLD FRONT PASSED YESTERDAY AFTN/EVENING...VARYING
AMOUNTS OF CLOUD COVER LINGER OVER UPPER MI EARLY THIS MORNING. OCNL
CLOUD COVER IS PROBABLY PREVENTING A MORE WIDESPREAD OR DENSE FOG
FROM DEVELOPING AS SEVERAL SITES HAVE HAD WIDELY FLUCTUATING VIS
DURING THE NIGHT.
WITH UPPER MI REMAINING FIRMLY UNDER THE INFLUENCE OF THE MID/UPPER
TROF TODAY AND TONIGHT...MAIN FCST ISSUE IS WHETHER ANY PCPN WILL
OCCUR. IN SUMMERTIME NW FLOW...EVEN THE SUBTLEST OF WAVES CAN
TRIGGER ISOLD/SCT CONVECTION. WHILE THERE ARE NO OBVIOUS SHORTWAVES
EVIDENT UPSTREAM IN NRN ONTARIO...THERE ARE HINTS OF ONE JUST N OF
LAKE SUPERIOR THAT IS ANALYZED BY THE LATEST RUC. THAT SUBTLE WAVE
IS PROBABLY RESPONSIBLE FOR THE RECENT EXPANSION OF CLOUDS OVER THE
FCST AREA AS WELL AS THE ISOLD SHRA THAT HAVE DEVELOPED FROM
ONTONAGON COUNTY N TO JUST OFFSHORE OF THE KEWEENAW PENINSULA. ONE
ASPECT THAT WILL BE WORKING AGAINST CONVECTION TODAY WILL BE THE
DRIER AIR MASS EVIDENT UPSTREAM IN NRN ONTARIO PER 00Z CWPL
SOUNDING. AS AN INDICATION OF THE DRIER AIR...THE K INDEX WAS 3. A
NICE SWATH OF CLEAR SKIES WAS ALSO EVIDENT ACROSS NRN ONTARIO TO THE
NW OF LAKE SUPERIOR YESTERDAY AFTN...AND SFC DWPTS WERE DOWN INTO
THE 30S IN THAT AREA. HOWEVER...WITH AFORMENTIONED SUBTLE WAVE
DRIFTING S...DEVELOPMENT OF LAKE BREEZE CONVERGENCE ZONE BTWN LAKE
SUPERIOR AND LAKE MI AND WITH MODELS DELAYING ARRIVAL OF THE DRIER
AIR UPSTREAM...A MENTION OF AT LEAST ISOLD SHRA APPEARS WARRANTED
FROM ROUGHLY NEAR KIMT E TO S OF KERY IN THE LAKE BREEZE CONVERGENCE
ZONE THIS AFTN. WILL ALSO NEED TO MONITOR TRENDS OVER THE NEXT FEW
HRS TO SEE IF CURRENT EXPANDING CLOUD COVER IS A PRECURSOR TO
MORNING SHRA DEVELOPMENT OVER A LARGER PORTION OF THE FCST AREA.
ANY SHRA NEAR LAKE MI WILL END EARLY THIS EVENING AS SHORTWAVE SLIPS
TO THE S. OTHERWISE...IT SHOULD BE A DRY NIGHT THOUGH THERE ARE
HINTS THAT ANOTHER WAVE MAY BE DROPPING INTO THE AREA OVERNIGHT.
WILL BE SOMETHING TO MONITOR FOR POSSIBLY ADDING SLIGHT CHC/ISOLD
SHRA IN LATER FCSTS. POTENTIAL CLOUD COVER WITH WEAK WAVE MAKES FOR
A CHALLENGING MIN TEMP FCST TONIGHT. AT THIS TIME...IT APPEARS CLOUD
COVER SHOULD BE LIMITED ENOUGH FOR AT LEAST THE FIRST PART OF THE
NIGHT TO FAVOR THE LOWER END OF AVBL GUIDANCE. SOME UPPER 30S WILL
BE POSSIBLE IN TRADITIONAL INTERIOR COLD SPOTS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 507 AM EDT SUN AUG 19 2012
GENERAL AGREEMENT IS PRESENT IN OVERALL UPPER AIR PATTERN THROUGH
THE UPCOMING WEEK. DEEP TROUGH OVER MOST OF EASTERN CANADA INTO THE
EASTERN CONUS /INCLUDING GREAT LAKES/ DE-AMPLIFIES BY WEDNESDAY. BY
THE MID-LATE WEEK...TROUGH OVER WESTERN CANADA INTO PACIFIC NORTHWEST
EJECTS A PIECE OF ENERGY INTO THE NORTHERN PLAINS. WHERE THAT WEAKER
TROUGH PROGRESSES IS A QUESTION AND WILL HAVE IMPACT ON FORECAST OVER
UPPER GREAT LAKES THURSDAY AND FRIDAY. FAIR TO SAY THAT AGREEMENT
FROM THE GFS/ECMWF/GEM-NHEM IS BETTER TO START THE WEEK THAN TO END
THE WEEK. MAIN ISSUE AT END OF WEEK IS HOW FAR EAST ENERGY OVER THE
NORTHERN PLAINS WILL MOVE INTO THE GREAT LAKES. GFS CONTINUES TO BE
DEEPER AND FARTHER EAST...RESULTING IN GOOD CHANCE OF PRECIPITATION
ON FRIDAY OVER UPPER MICHIGAN. ECWMF/EXTRAPOLATION OF GEM-NHEM WOULD
KEEP MAJORITY OF FORCING AND PRECIPITATION WITH THE WEAKER TROUGH
SOUTHWEST OF UPPER MICHIGAN INTO THE UPPER MISSISSIPPI RIVER VALLEY.
TO START THE LONG TERM...HAVE A SMALL SHOT AT ISOLD SHRA ON MONDAY
OVER CENTRAL CWA IN THE MID-LATE AFTERNOON AS LAST OF STRONGER
SHORTWAVES DROP SOUTH ON WESTERN PERIFERY OF LARGER SCALE UPPER
TROUGH. FORECAST SOUNDINGS FROM GFS AND NAM INDICATE MOISTURE OVER
THE CWA ONLY FOCUSES BETWEEN 800MB AND 700MB. DRY AIR BELOW LCL
IS QUITE DRY AS DAY BEGINS WITH DEWPOINTS IN THE 30S. PROBABLY WILL
ONLY SEE DEWPOINTS RISE INTO THE MID 40S AT BEST IN THE AFTERNOON AS
LOW-LEVEL MOISTURE ADVECTION IS LIMITED. SREF IDEA SHOWING QPF
FORMING OVER SCNTRL CWA AFTER 18Z IS LIKELY ON TRACK. COVERAGE OF ANY
SHRA WILL BE VERY ISOLATED DUE TO DRY LOW-LEVELS. NO TSRA INCLUDED
WITH POOR MID-LEVEL LAPSE RATES LESS THAN 6C/KM AND SBCAPE VALUES
ONLY UP TO 200 J/KG. MODELS HINT AT MID-LEVEL MOISTURE STICKING
AROUND OFF AND ON THROUGH MONDAY NIGHT BUT WITH SAME LIMITING FACTORS
AS MONDAY AFTERNOON DO NOT EXPECT MUCH IN WAY OF PRECIPITATION ON
MONDAY NIGHT.
COUPLE OF WEAKER SHORTWAVES RIPPLE THROUGH UPPER GREAT LAKES TUESDAY
BUT MOISTURE IS FORECAST TO BE EVEN SHALLOWER THAN ON MONDAY...AGAIN
CENTERED AROUND 800MB. ADDITIONAL MID-LEVEL MOISTURE COULD ROLL
ACROSS WITH SCT-BKN CLOUDS 15-20 KFT POSSIBLE. MIX OF CLOUDS AND
SUNSHINE GIVES WAY TO MORE SUNSHINE IN THE AFTERNOON...SO BASED ON
H85 TEMPS TOWARD AOA 12C EXPECT MAX TEMPS WELL INTO THE 70S FOR MOST
AREAS WITH EVEN A POTENTIAL OF SEEING SOME READINGS AROUND 80
DEGREES OVER WESTERN AND CENTRAL CWA.
LOOKING WELL TO THE NORTHWEST CURRENTLY THERE IS A PRETTY STRONG
SHORTWAVE CRESTING RIDGE OVER WESTERN CONUS INTO WESTERN CANADA.
WAVES IS OVER THE NORTHWEST TERRITORIES OF CANADA. MODELS SHOW WAVE
SPLITTING BUT ONE FORMIDABLE PIECE OF SHORTWAVE ENERGY IS FORECAST
TO DIG INTO NORTHWEST ONTARIO TUESDAY NIGHT INTO WEDNESDAY. GFS
FARTHER SOUTH WITH THE WAVE AND ASSOCIATED PRECIPITATION...BUT
ECMWF AND GEM-NHEM HAVE THE WAVE AS WELL...BUT NOT AS FAR SOUTH. NAM
APPEARS TOO FAST/WEAK WITH THE SHORTWAVE AND IS NOT PREFERRED. ALL
THE MODELS INDICATE AREA OF H85 TEMP AND H85-H7 MOISTURE ADVECTION
SETS UP JUST AHEAD OF THE WAVE AS IT DIGS TOWARD UPPER GREAT LAKES
TUESDAY NIGHT. USING BLEND OF LAST FEW GFS MODEL RUNS ALONG WITH
ECMWF/GEM-NHEM AND EVEN SOME OF THE SREF...KEPT POPS HIGHEST ON
TUESDAY NIGHT OVER NORTHERN SECTIONS OF LK SUPERIOR...AND NO REAL
POPS OVER LAND AREA OF UPPER MICHIGAN...ASIDE FROM ISLE ROYALE.
IDEA FITS SYNOPTIC PATTERN AS MOST LAND CWA WILL BE THE WITHIN THE
MORE UNFAVORABLE RIGHT EXIT REGION OF JET STREAK FOR PRECIPITATION.
KEPT SLIGHT CHANCES FOR WEDNESDAY OVER CENTRAL AND EAST AS LARGER
SCALE FORCING ALONG WITH WEAK SFC TROUGH COULD COMBINE WITH DAYTIME
HEATING TO HELP FORM SOME SHOWERS DURING THE PEAK HEATING OF THE DAY.
IN THE EXTENDED...00Z MODEL RUNS PROVIDE NO TRENDS OF NOTE ON EXTENT
OF LARGER SCALE TROUGHING OVER UPPER GREAT LAKES TO CLOSE THE WEEK.
GFS CONTINUES TO SHOVE UPPER TROUGH PUSHING INTO THE NORTHERN PLAINS
ON THURSDAY ON INTO THE UPPER GREAT LAKES ON FRIDAY. THE TROUGH ALONG
WITH INCREASING LOW-LEVEL MOISTURE ADVECTION AND PRESENCE OF SFC WARM
FRONT HELPS TO GENERATE PLENTY OF QPF FRIDAY INTO FRIDAY NIGHT. ON
THE FLIP SIDE THE LATEST ECMWF IS MORE SHUNTED TO THE SOUTHWEST WITH
THE UPPER TROUGH AND THUS BRINGS VERY LITTLE QPF INTO THE UPPER GREAT
LAKES WITH HIGH PRESSURE STAYING THE DOMINANT FEATURE. MAIN WARM
FRONT REMAINS WELL TO THE SOUTH OF CWA. LATEST CANADIAN LOOKS MORE
LIKE THE ECMWF BUT DOES TRY TO BRING SOME QPF INTO AT LEAST WESTERN
CWA ON FRIDAY. MODEL CONSENSUS INDICATES HIGHEST CHANCES FOR
PRECIPITATION FRIDAY INTO FRIDAY NIGHT...BUT THIS IS BEING BIASED
SOMEWHAT BY GFS MODEL ELEMENTS. WILL STAY WITH CONSENSUS GIVEN THE
STARK DIFFERENCES OFFERED UP BY ECMWF AND GFS...BUT CERTAINLY
POSSIBLE THAT FRIDAY MAY END UP MAINLY DRY COMPARED TO THE HIGHER
CHANCE POPS IN THIS FORECAST. DOES APPEAR THAT NEXT WEEKEND WOULD
FEATURE A DRYING TREND AS THE UPPER TROUGH DEPARTS THE AREA. TOUGH TO
GET TOO SPECIFIC ABOUT THOSE DETAILS THOUGH DUE TO THE MODEL
DIFFERENCES STILL AROUND LEADING INTO NEXT WEEKEND. TEMPERATURES
SHOULD SHOW WARMING TREND INTO NEXT WEEKEND AS H85 TEMPS STEADILY
CLIMB FROM WEDNESDAY TO SATURDAY. IF GFS IS CORRECT THOUGH...WARMING
WOULD BE TEMPERED THURSDAY AND DEFINITELY INTO FRIDAY WITH MORE
CLOUDS AND PRECIPITATION. &&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 137 AM EDT SUN AUG 19 2012
AREAS OF FOG CONTINUE TO PLAGUE PORTIONS OF UPPER MICHIGAN ALTHOUGH
DRIER AIR IS ATTEMPTING TO MOVE INTO THE REGION FROM THE NORTH.
SATELLITE IMAGERY SHOWS NARROW SLOT OF CLEAR SKIES PUSHING INTO THE
AREA WITH AN AREA OF MID CLOUDS RIGHT BEHIND THIS FEATURE. CLEARING
SKIES AND SUBSIDENCE SUPPORTS PATCHY FOG DEVELOPMENT IN THOSE AREAS
THAT RECEIVED DECENT AMOUNTS OF RAINFALL. LESS ANTECEDENT MOISTURE
AT KCMX SUGGESTS FOG WILL NOT BE AS PREVALENT THERE. TAF FORECASTS
TO BE VERY TRICKY AT KIWD AND KSAW AS VIS AND CIGS WILL VARY
SIGNIFICANTLY FOR SOME TIME. ONCE THE INVERSION STRENGTHENS...MVFR
AND OCCASIONAL IFR CIGS/VIS TO PREVAIL. AS HIGH PRESSURE BUILDS INTO
THE AREA IN EARNEST...VFR CONDITIONS WILL THEN PREVAIL THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 AM EDT SUN AUG 19 2012
BRIEFLY TIGHTER PRESSURE GRADIENT WILL ALLOW NORTHWEST WIND GUSTS
TO REACH 20-25 KTS OVER EASTERN SECTIONS OF LK SUPERIOR THIS
AFTERNOON INTO THIS EVENING. WINDS DIMINISH OVERNIGHT TONIGHT AND
REMAIN MAINLY BELOW 20 KTS THROUGH WEDNESDAY AS HIGH PRESSURE STAYS
CLOSE BY. EXCEPTION COULD BE TUESDAY AFTERNOON AND EVENING OVER
WESTERN SECTIONS WITH SOUTHWEST WIND GUSTS PUSHING ABOVE 20 KTS IN
THE VICINITY OF ISLE ROYALE. LOW PRESSURE SYSTEM APPROACHING LATE
THIS WEEK RESULTS IN WINDS BECOMING MORE EAST TO SOUTHEAST AND
INCREASING OVER 20 KTS. WINDS MAY END UP HIGHER DEPENDING ON
ULTIMATE TRACK AND STRENGTH OF SURFACE LOW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...RJT
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
140 AM EDT SUN AUG 19 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 359 PM EDT SAT AUG 18 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF OVER
ERN NAMERICA CENTERED AROUND CUTOFF UPR LO NEAR JAMES BAY. THERE ARE
SEVERAL SHRTWVS ROTATING THRU THE TROF AND ARND THIS FEATURE. THE
FIRST IS SETTLING S THRU ONTARIO WHILE ANOTHER NEAR LK WINNIPEG IS
DIVING SSEWD TOWARD NW MN. AT 15Z...THESE SHRTWVS/ACCOMPANYING SFC
TROF OVER LK SUP WITH SHARP WSHFT WERE SUPPORTING A BKN LINE OF SHRA
EXTENDING FM ERN LK SUP ACRS THE KEWEENAW THRU NRN MN TOWARD LK
WINNIPEG. THE 12Z INL RAOB SHOWS ABUNDANT MID LVL MSTR ABV A DRIER
SUB H75 LYR...AND THIS LOWER LVL DRY AIR SEEMS TO BE THE BIGGEST
IMPEDIMENT TO MORE WDSPRD SHRA. THE DRY AIR IS DEEPER TO THE S AS
INDICATED BY THE 12Z GRB RAOB...AND THE MRNG WAS MOSUNNY OVER THE
SCNTRL. TO THE N...MUCH DRIER LLVL AIR IS PRESENT ON THE 12Z YPL
RAOB UNDER HI PRES RDG AXIS EXTENDING SEWD INTO NW ONTARIO FM HI
PRES CENTERED OVER NRN MANITOBA. MODIFIED
LATE THIS AFTN...WITH ARRIVAL OF SFC TROF/ENHANCED LLVL CNVGC
ASSOCIATED WITH SHARP SYNOPTIC WSHFT THAT WL BE ENHANCED BY
BREEZE OFF LK SUP DURING PEAK HEATING TIME...THE SHRA HAVE BECOME
MORE NMRS WITH SOME EMBEDDED TS ON A LINE THRU THE CNTRL ZNS.
MODIFIED 12Z INL RAOB FOR SFC T/TD OF 75/47 YIELDS SBCAPE UP TO 600
J/KG. ALTHOUGH SHRA COVERAGE IS STILL LIMITED OVER THE SCNTRL BY
LINGERING LLVL DRY AIR...EXPECT THESE SHRA TO SPREAD INTO THAT AREA
AS THE DRY AIR RETREATS. THE INTENSITY OF THE TS WL BE LIMITED BY
DRY LLVL AIR...ENVIRONMENTAL LAPSE RATES NOT FAR FM MOIST
ADIABATIC/DEEP SKINNY CAPE...LACK OF MID LVL DRY AIR THAT KEEPS
SFC-10K FT DELTA THETA-E NO HIER THAN 5-10C...AND RELATIVELY WEAK
DEEP LYR SHEAR NO GREATER THAN 15-25 KTS. ALTHOUGH SOME STORMS HAVE
PULSED AT TIMES...THE SMALL CORES HAVE NOT PERSISTED AND REMAINED
NEARLY VERTICAL...CONSISTENT WITH A WEAK SHEAR ENVIRONMENT. LO FRZG
LVL NOT FAR FM 9K FT AGL INDICATES THE STRONGER CELLS MIGHT DROP
SOME SMALL HAIL.
TONIGHT...MAIN FCST CONCERNS BECOME HOW QUICKLY DRIER AIR OVER
ONTARIO CAN MOVE INTO THE UPR LKS AND COUNTER LINGERING DYNAMIC
SUPPORT ASSOCIATED WITH DISTURBANCE NOW NEAR LK WINNIPEG THAT IS
FCST TO DROP SEWD INTO NW WI BY 12Z SUN AND SHARPEN UPR TROF AXIS
EXTENDING FM CLOSED LO NEAR JAMES BAY SWWD THRU UPR MI. LOSS OF
DAYTIME HEATING WL ALSO ENHANCE SHRA DISSIPATION. THE NAM IS MOST
AGGRESSIVE WITH UPR DRYING AND SHOWS ANY LINGERING -SHRA OVER THE
SCNTRL ENDING BY 03Z. THE BULK OF THE OTHER GUIDANCE MAINTAINS THE
-SHRA MAINLY OVER THE SCNTRL THRU MUCH OF THE NGT. HOWEVER...
CONSIDERING THE LLVL DRYNESS OF THE 12Z YPL RAOB AND RATHER
AGGRESSIVE DRYING TAKING PLACE OVER THE N PORTIONS OF LK SUP/
ADJOINING ONTARIO...THE NAM MIGHT BE ON THE RIGHT TRACK. SINCE ALL
THE MODELS ALSO SHOW LIMITED DEEP LYR QVECTOR CVNGC AS ANY DPVA
AHEAD OF SHRTWV IS OFFSET BY DRYING...TENDED TO CUT POPS A BIT
FASTER THAN GOING FCST WITH SMALL CHC POPS LINGERING ONLY OVER THE
FAR SCNTRL NEAR MNM LATER TNGT. ALTHOUGH LGT WINDS ASSOCIATED WITH
BLDG HI PRES MOVING TOWARD WRN UPR MI TOWARD 12Z/AGGRESSIVE MID LVL
DRYING MIGHT SUPPORT FOG FORMATION ESPECIALLY IN AREAS THAT GET RA
THIS AFTN/EVNG...WL KEEP FOG OUT OF FCST EXCEPT FOR OVER THE
INTERIOR WCNTRL...WHERE THE GFS HINTS THE LLVL DRYING WL BE LESS
PRONOUNCED AND SREF PROB VSBY UNDER 1 MILE IS HIER AND WHERE MIN
TEMPS ARE LIKELY TO BE LOWEST ARND 40.
SUN...CWA IS FCST TO REMAIN UNDER UPR TROF EXTENDING SWWD FM HUDSON
BAY. THE 12Z NAM/LOCAL WRF-ARW SHOW A SFC RDG AXIS EXTENDING FM WRN
LK SUP THRU THE CWA BRINGING A DRY DAY. THE 12Z GFS/CNDN MODELS ON
OTHER HAND SHOW A WEAKER SFC RDG...WITH A WEAKER GRADIENT ALLOWING
SOME LK BREEZE CNVGC/WEAK LO PRES TROF OVER THE SCNTRL...WHERE THESE
MODELS GENERATES SOME INSTABILITY -SHRA IN THE AFTN. CONSIDERING THE
WARM/DRY H7-5 LYR/LO FCST KINX ARND 18 BY THE GFS IN THIS AREA...
OPTED TO MAINTAIN GOING DRY FCST. WITH H85 TEMPS FCST TO BE ARND 8C
AND MIXING TO H75 ON GFS FCST SDNGS...EXPECT HI TEMPS TO REACH THE
MID 70S NEAR THE WI BORDER/SCNTRL AWAY FM LK MODERATION.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 359 PM EDT SAT AUG 18 2012
UPPER-LEVEL CONDITIONS WILL REMAIN SUPPORTIVE OF A SUBTLE SERIES OF
TROUGHS AND RIDGES THROUGH MONDAY. DRY CONDITIONS WILL THEN BUILD IN
FOR THE MIDDLE OF THE WEEK BEFORE A WARM...AND POTENTIALLY WET...END
TO THE WEEK.
SUNDAY NIGHT AND MONDAY...NAM/GFS/ECMWF/GEM HAVE COME INTO GOOD
AGREEMENT ON THE SYNOPTIC PATTERN ACROSS CENTRAL AND EASTERN NORTH
AMERICA THROUGH TUESDAY...SO OVERALL CONFIDENCE OF THE FORECAST IN
THIS TIME PERIOD IS FAIRLY GOOD.
A PERSISTENT MID-LEVEL LOW OVER JAMES BAY WILL BEGIN TO MOVE
NORTHEAST SUNDAY NIGHT AS A BROAD MID-LEVEL RIDGE OVER THE WESTERN
THIRD OF THE CONUS COMMENCES DEAMPLIFICATION WHILE DRIFTING EASTWARD
TOWARD THE UPPER GREAT LAKES REGION. A SERIES OF SHORTWAVE TROUGHS
WILL CONTINUE TO TRACK AROUND THE BACKSIDE OF THE LOW OVER JAMES
BAY. THE FIRST OF THOSE IS MOVING THROUGH THE AREA TODAY. THEN...A
SECOND TROUGH BEHIND TODAYS TROUGH WILL CROSS THE AREA ON
SUNDAY...AND BE EXITING TO THE SOUTHEAST OUT OF UPPER MI BY SUNDAY
EVENING. A SHORTWAVE RIDGE WILL THEN BRIEFLY MOVE IN SUNDAY EVENING
AHEAD OF YET ANOTHER WEAK SHORTWAVE TROUGH CROSSING THE CWA ON
MONDAY.
THE WEAK INCOMING RIDGE COMBINED WITH PLENTY OF DRY AIR THROUGHOUT
THE COLUMN SHOULD LIMIT THE CHANCE OF ANY PRECIP BY SUNDAY EVENING.
ATTENTION IS PLACED MOSTLY ON THE POTENTIAL OF TEMPERATURES NEARING
FROST CRITERIA/ 36F/ INTERIOR WEST SUNDAY NIGHT. DIFFICULTY OF
PINNING DOWN EXACT LOW TEMPS RESIDES WITH WINDS AND THE CLOUD COVER
PATTERN BETWEEN THE TROUGH ON MONDAY AND THE ONE ON TUESDAY.
FIRST...DRY AIR AND SUBSIDENCE WILL ERODE REMAINING CLOUDS FROM
SUNDAYS SHORTWAVE. SEVERAL MODELS ARE SHOWING AN ENHANCED LAYER OF
MOISTURE BETWEEN 800 AND 700MB MOVING INTO THE AREA LATE SUNDAY
NIGHT. THIS IS LIKELY RESIDUAL MOISTURE FROM DIURNAL CUMULUS ON
SUNDAY...AS IS NOTED WITH THE UPSTREAM SATELLITE IMAGES IN NORTHERN
MANITOBA...SO DO NOT THINK LOW CLOUDS WILL BE A FACTOR. AIR ABOVE
THE MID-LEVELS WILL BE QUITE DRY...WHICH IS ALSO NOTED ON IR/VIS
SATELLITE IMAGES FROM UPSTREAM. BEHIND A WEAK SFC RIDGE SUNDAY
EVENING...WINDS MAY END UP BEING THE LIMITING FACTOR AS THE PRESSURE
GRADIENT INCREASES WITH HIGH PRESSURE UNDER THE WESTERN RIDGE
BUILDING INTO THE REGION. THE LOW-LEVELS SHOULD BE ABLE TO DECOUPLE
ENOUGH...ESPECIALLY IN THE TYPICAL COLD SPOTS. ULTIMATELY...WILL
KEEP ONGOING FORECAST OF MID TO UPPER 30S WELL INLAND...AND LEAVE
PATCHY FROST OUT OF THE FORECAST FOR RIGHT NOW.
THE THIRD SHORTWAVE TROUGH IS PROGGED TO MOVE ACROSS THE CWA
THROUGHOUT THE DAY ON MONDAY. NOT MUCH IN THE WAY OF MOISTURE WITH
THIS SHORTWAVE EITHER. HOWEVER...AS THE INFLUENCE FROM THE TROUGH
APPROACHES THE SOUTH CENTRAL CWA...H8 WAA/MOISTURE TRANSPORT MAY
ASSIST WITH KICKING OFF SOME ISOLATED SHOWERS. LOW-LEVEL DRY AIR MAY
INHIBIT SHOWERS SOMEWHAT...SO WILL ONLY PUT A SLIGHT CHANCE IN THE
FORECAST FOR THE SOUTH-CENTRAL CWA. H8 TEMPS AROUND 7-8C SHOULD
YIELD HIGHS AROUND 70 FOR MOST LOCATIONS.
MONDAY NIGHT AND TUESDAY...THE DE-AMPLIFYING RIDGE FROM THE WESTERN
STATES WILL MOVE OVER UPPER MI MONDAY NIGHT...LEADING TO MOSTLY
CLEAR SKIES AND ANOTHER ROUND OF GOOD RADIATIONAL COOLING. THIS
TIME...DEW POINTS WILL BE MUCH HIGHER...SO MOST INLAND LOCATIONS
SHOULD STAY ABOVE 40. SUBSIDENCE FROM THE RIDGE WILL KEEP CONDITIONS
DRY THROUGH TUESDAY. H8 TEMPS FROM 10-12C WOULD RESULT IN MID 70S
FOR HIGHS ACROSS MOST OF THE CWA ON TUESDAY...WITH SLIGHTLY COOLER
TEMPS EAST IN REGIONS AFFECTED BY LAKE BREEZES FROM LAKES MICHIGAN
AND SUPERIOR.
TUESDAY NIGHT THROUGH SATURDAY...THE REMNANTS OF THE LOW CURRENTLY
OVER JAMES BAY WILL BE IN FAR NORTHERN QUEBEC BY TUESDAY NIGHT. A
SHORTWAVE TROUGH ROTATING AROUND THE BACK OF THE LOW IS PROGGED
TO MOVE THROUGH NORTHERN ONTARIO TUESDAY NIGHT INTO WEDNESDAY. THE
ECMWF HAS BEEN TRENDING FARTHER NORTH WITH THIS SYSTEM. MEANWHILE
THE GFS HAS BECOME THE MORE SOUTHERN SOLUTION. PREFER THE TREND OF
THE ECMWF AS THE WAVE WILL BE ATTEMPTING TO DIG INTO THE EASTERN
EDGE OF A NOW BUILDING WESTERN RIDGE. EXPECTATION IS THAT PRECIP
WILL STAY OUT OF THE AREA UNTIL LATE WEDNESDAY AS AN ASSOCIATED SFC
COLD FRONT STALLS OVER LAKE SUPERIOR...THOUGH THE FINAL LOCATION OF
THIS FEATURE IS STILL A LITTLE INCONSISTENT IN THE MODELS.
DRY AIR ABOVE THE LOWEST FEW KFT WILL ALLOW FOR DECENT MIXING ON
BOTH TUESDAY AND WEDNESDAY. LOWERED DAYTIME DEW POINTS ABOUT 5F FROM
PREVIOUS FORECAST FOR BOTH DAYS. THIS RESULTS IN MIN RH VALUES
AROUND 40 PERCENT BOTH DAYS. HOWEVER...FEELING IS THAT THE TREND
WILL BE TOWARD LOWER RH VALUES WITH PROCEEDING FORECASTS.
A DEEP TROUGH MOVING ONTO THE WEST COAST TUESDAY WILL THEN REACH THE
UPPER MS VALLEY BY LATE FRIDAY. THE INDUCED SFC LOW IS EXPECTED TO
BRING THE STALLED SFC BOUNDARY BACK NORTHWARD AS A WARM FRONT. HIGH
TEMPS DURING THIS TIME WILL LIKELY BE ABOVE NORMAL /AROUND 80/ DUE
TO SOUTHERLY FLOW SOUTH OF THE STALLED BOUNDARY...BUT AS NOTED
BEFORE...UNCERTAINTY STILL EXISTS IN THE FINAL LOCATION OF THE
BOUNDARY. WILL STICK WITH CONSENSUS OF MODEL THROUGHOUT THIS TIME
FRAME GIVEN DECENT AGREEMENT FOR THIS FAR OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 137 AM EDT SUN AUG 19 2012
AREAS OF FOG CONTINUE TO PLAGUE PORTIONS OF UPPER MICHIGAN ALTHOUGH
DRIER AIR IS ATTEMPTING TO MOVE INTO THE REGION FROM THE NORTH.
SATELLITE IMAGERY SHOWS NARROW SLOT OF CLEAR SKIES PUSHING INTO THE
AREA WITH AN AREA OF MID CLOUDS RIGHT BEHIND THIS FEATURE. CLEARING
SKIES AND SUBSIDENCE SUPPORTS PATCHY FOG DEVELOPMENT IN THOSE AREAS
THAT RECEIVED DECENT AMOUNTS OF RAINFALL. LESS ANTECEDENT MOISTURE
AT KCMX SUGGESTS FOG WILL NOT BE AS PREVALENT THERE. TAF FORECASTS
TO BE VERY TRICKY AT KIWD AND KSAW AS VIS AND CIGS WILL VARY
SIGNIFICANTLY FOR SOME TIME. ONCE THE INVERSION STRENGTHENS...MVFR
AND OCCASIONAL IFR CIGS/VIS TO PREVAIL. AS HIGH PRESSURE BUILDS INTO
THE AREA IN EARNEST...VFR CONDITIONS WILL THEN PREVAIL THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT AUG 18 2012
A GENERALLY WEAK PRES GRADIENT DOMINATING THE UPPER GREAT LAKES WILL
RESULT IN WINDS MOSTLY UNDER 20KT THRU THU. THE PRES GRADIENT WILL
BECOME A BIT SHARPER TUE NIGHT AS A LO PRES TROF MOVES ACROSS
CENTRAL ONTARIO...RESULTING IN WSW WINDS UP TO 25 KTS OVER PORTIONS
OF THE W AND NORTH CENTRAL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TK
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
141 PM CDT SUN AUG 19 2012
.UPDATE...
UPDATED TO INCLUDE 18Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
RATHER AMPLIFIED UPPER AIR PATTERN REMAINS IN PLACE THIS
MORNING...WITH SHARP UPPER RIDGE UP THE ROCKY MOUNTAINS FLANKED
BY A DEEP CLOSED LOW NEAR HUDSON BAY AND A LONGWAVE TROUGH OVER
THE NERN PAC. WITHIN THE NNW FLOW OVERHEAD...WATER VAPOR IMAGERY
AND RAP PV ANALYSIS SHOWS A POTENT WAVE DROPPING INTO CENTRAL MN
AT 8Z. AT THE SFC...HIGH PRESSURE WAS PARKED ACROSS MUCH OF THE
GREAT PLAINS WITH A WEAK FRONT/WIND SHIFT STILL EVIDENT IN THE FLOW
FROM MADISON...MN ACROSS THE TWIN CITIES AND OVER TOWARD GREEN
BAY.
ALOFT...PATTERN WILL UNDERGO A SLOW DE-AMPLIFICATION OVER THE
COMING DAYS. BY THE MIDDLE OF NEXT WEEK...WEAK ZONAL FLOW WILL BE
IN PLACE ACROSS MUCH OF THE CONUS AS ROCKIES RIDGE FLATTENS
OUT...THE HUDSON LOW FILLS/LIFTS NE AND THE PAC TROUGH MOVES INTO
BC AND UNDERGOES SOME DEEPENING. MEDIUM RANGE MODELS DO NOT BRING
THE WRN WAVE ACROSS THE CENTER OF THE CONTINENT UNTIL NEXT
WEEKEND.
AT THE SFC...FRONT SPLITTING THE MPX CWA NEARLY IN HALF THIS
MORNING WILL SLOWLY WASH OUT DURING THE DAY AS HIGH PRESSURE ACROSS
THE DAKOTAS PUSHES EAST. THIS HIGH PRESSURE WILL THEN SLOWLY TRACK
ACROSS THE UPPER MS VALLEY THROUGH TUESDAY NIGHT. WEDNESDAY...A
WEAK FRONTAL BOUNDARY WILL TRY TO SAG INTO THE LAKE SUPERIOR
REGION AS A LEE THROUGH SLOWLY TAKES SHAPE ACROSS THE HIGH PLAINS AS
UPPER FLOW BECOMES MORE ZONAL. THE FIRST FRONTAL PUSH FROM THIS
LEE TROUGHING LOOKS TO TRY AND PUSH INTO THE MPX AREA
THU/FRI...WITH A MORE SIGNIFICANT FRONT NOT LIKELY TO ARRIVE UNTIL
NEXT WEEKEND WITH THE STRONGER UPPER FORCING.
FOR TODAY THERE ARE TWO CONCERNS THANKS TO SHORTWAVE NOW IN
CENTRAL MN. FIRST IS HOW FAR NORTH TO KEEP POPS TODAY...WHILE THE
SECOND IS WHAT IMPACT WILL CLOUDS HAVE ON MAX TEMPS. FOR
PRECIP...TRIED LIMITING MENTIONABLE PRECIP TO WHERE MODELS SHOW
K-INDEX EXCEEDING 28. GOING BACK TO YESTERDAY...THIS MATCHED UP
FAIRLY WELL WITH WHERE SHOWERS/STORMS WERE ABLE TO FIRE OFF.
THOUGH MODELS DIFFER ON HOW QUICKLY THE H7 THROUGH/MOISTURE MAKE
IT THROUGH THE REGION...THEY ARE ALL FAIRLY SIMILAR WITH THEIR
K-INDEX FORECASTS...WHICH MATCHES UP WELL WITH 19.03 SREF PROBS.
HAVE HIGHEST POPS ACROSS SOUTH CENTRAL MN THIS MORNING...WITH ISO
STORMS LINGERING INTO THE AFTERNOON ALONG I-90. HOWEVER...THERE
IS SUPPORT FROM THE 19.00 ECMWF/GFS ALONG WITH HRRR REFLECTIVITY
FORECASTS FOR HAVE POPS FARTHER NORTH THAN CURRENTLY INDICATED FOR
TODAY. IF THE GFS/ECMWF ENDS UP BEING THE ROUTE THINGS TAKE FOR
TODAY...THEN IT WILL LIKELY END BEING MOSTLY CLOUDY ACROSS SOUTH
CENTRAL MN...WHERE HIGHS COULD END UP SEVERAL DEGREES COOLER THAN
CURRENTLY INDICATED.
PRECIP WILL QUICKLY CUT OFF THIS EVENING...WITH SKIES BECOMING
CLEAR. THIS WILL SET THE STAGE FOR RATHER TRANQUIL WEATHER FOR
SUNDAY THROUGH WEDNESDAY AS THE SFC HIGH SLOWLY SLIDES EAST. WITH
H5 HEIGHTS AND H85 TEMPS SLOWLY BUILDING DURING THIS PERIOD...WILL
SEE HIGHS TICK UP A COUPLE OF DEGREES EACH DAY. BY WEDNESDAY...THE
RETURN OF SOUTHERLY FLOW WILL HELP BOAST TEMPS BACK INTO THE
LOWER 80S...ALONG WITH SENDING DEWPS BACK INTO THE 60S.
FOR WEDNESDAY NIGHT THROUGH FRIDAY...UNCERTAINTY IN THE FORECAST
INCREASES QUITE A BIT. THOUGH THE MEDIUM RANGE MODELS GENERALLY
AGREE ON WEAK ZONAL FLOW SETTING UP ACROSS THE NRN CONUS THIS
PERIOD...THEY DIFFER ON THE HANDLING OF A SHORT WAVE PEGGED TO
MOVE THROUGH THIS FLOW FROM THURSDAY INTO FRIDAY. THE GFS
CONTINUES TO BE THE MOST AGGRESSIVE WITH THE WAVE...BRINGING A
NEGATIVELY TILTED SHORTWAVE AND ASSOCIATED COLD FRONT ACROSS THE
AREA THURSDAY NIGHT INTO FRIDAY. THE ECMWF SHOWS A MUCH
WEAKER/SLOWER WAVE WORKING INTO THE PLAINS...WITH VERY LITTLE IN
THE WAY OF PRECIP WORKING INTO THE AREA UNTIL THE WEEKEND FRONT.
FOR THIS PERIOD...FOLLOWED THE BLEND APPROACH WITH THE CONTINUED
MENTION OF 40-50 POPS THURSDAY NIGHT. HARD TO SAY WHICH WAY THINGS
MAY GO AT THIS POINT...BUT IT DOES APPEAR THE GFS IS SUFFERING
FROM SOME CONVECTIVE FEEDBACK WHICH IS LIKELY IMPACTING THE
STRENGTH OF SFC FEATURES IT SHOWS.
&&
.AVIATION.../00Z TAF ISSUANCE/
VFR FOR THIS TAF SET. CDFNT NOW S OF MN AND INTO FAR SRN WI WILL
CONTINUE TO PUSH OFF TO THE S AND E THRU TNGT...BEING REPLACE BY
INCOMING HIGH PRES. GENERALLY FAIR WX CUMULUS CLOUD DEVELOPMENT
THIS AFTN BUT ONE POTENTIAL PROBLEM MAY BE ISOLD SHWRS NEAR THE
IA/MN BORDER LATE THIS AFTN INTO EARLY THIS EVE. SHORT-TERM MODELS
INDICATE ISOLD TO SCATTERED SHOWER DEVELOPMENT...IN RESPONSE TO
THE WOBBLING CDFNT AND A SHORTWAVE TROUGH AXIS SWINGING AROUND THE
PERIPHERY OF A DEPARTING UPPER LEVEL LOW. ONLY KRWF LOOKS
SUSCEPTIBLE TO SHOWERS WHILE ALL OTHER TAF SITES REMAIN DRY. SKIES
CLEAR OUT BY LATE EVENING AND WILL REMAIN CLEAR THRU TMRW AFTN.
MAINLY N WINDS...DROPPING OFF OVERNIGHT THEN PICKUP UP ONCE AGAIN
TMRW...LESS THAN 10 KT.
KMSP...VFR THROUGHOUT WITH VERY LITTLE AVIATION CONCERNS.
SCATTERED FAIR WX CUMULUS DEVELOPMENT THIS AFTN WILL GIVE WAY TO
CLEAR SKIES TNGT THRU TMRW. MAINLY N WINDS IN THE 5-9 KT RANGE
THIS AFTN...DROPPING OFF TONIGHT THEN PICKING UP AGAIN TMRW.
/OUTLOOK FOR KMSP/
MON NIGHT...VFR. LIGHT/VARIABLE WINDS.
TUE...VFR. SOUTHWEST 5 TO 10 KT.
WED...VFR. SOUTH 5 TO 10 KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
629 AM CDT SUN AUG 19 2012
.UPDATE...FOR 12Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 350 AM CDT SUN AUG 19 2012/
RATHER AMPLIFIED UPPER AIR PATTERN REMAINS IN PLACE THIS
MORNING...WITH SHARP UPPER RIDGE UP THE ROCKY MOUNTAINS FLANKED
BY A DEEP CLOSED LOW NEAR HUDSON BAY AND A LONGWAVE TROUGH OVER
THE NERN PAC. WITHIN THE NNW FLOW OVERHEAD...WATER VAPOR IMAGERY
AND RAP PV ANALYSIS SHOWS A POTENT WAVE DROPPING INTO CENTRAL MN
AT 8Z. AT THE SFC...HIGH PRESSURE WAS PARKED ACROSS MUCH OF THE
GREAT PLAINS WITH A WEAK FRONT/WIND SHIFT STILL EVIDENT IN THE FLOW
FROM MADISON...MN ACROSS THE TWIN CITIES AND OVER TOWARD GREEN
BAY.
ALOFT...PATTERN WILL UNDERGO A SLOW DE-AMPLIFICATION OVER THE
COMING DAYS. BY THE MIDDLE OF NEXT WEEK...WEAK ZONAL FLOW WILL BE
IN PLACE ACROSS MUCH OF THE CONUS AS ROCKIES RIDGE FLATTENS
OUT...THE HUDSON LOW FILLS/LIFTS NE AND THE PAC TROUGH MOVES INTO
BC AND UNDERGOES SOME DEEPENING. MEDIUM RANGE MODELS DO NOT BRING
THE WRN WAVE ACROSS THE CENTER OF THE CONTINENT UNTIL NEXT
WEEKEND.
AT THE SFC...FRONT SPLITTING THE MPX CWA NEARLY IN HALF THIS
MORNING WILL SLOWLY WASH OUT DURING THE DAY AS HIGH PRESSURE ACROSS
THE DAKOTAS PUSHES EAST. THIS HIGH PRESSURE WILL THEN SLOWLY TRACK
ACROSS THE UPPER MS VALLEY THROUGH TUESDAY NIGHT. WEDNESDAY...A
WEAK FRONTAL BOUNDARY WILL TRY TO SAG INTO THE LAKE SUPERIOR
REGION AS A LEE THROUGH SLOWLY TAKES SHAPE ACROSS THE HIGH PLAINS AS
UPPER FLOW BECOMES MORE ZONAL. THE FIRST FRONTAL PUSH FROM THIS
LEE TROUGHING LOOKS TO TRY AND PUSH INTO THE MPX AREA
THU/FRI...WITH A MORE SIGNIFICANT FRONT NOT LIKELY TO ARRIVE UNTIL
NEXT WEEKEND WITH THE STRONGER UPPER FORCING.
FOR TODAY THERE ARE TWO CONCERNS THANKS TO SHORTWAVE NOW IN
CENTRAL MN. FIRST IS HOW FAR NORTH TO KEEP POPS TODAY...WHILE THE
SECOND IS WHAT IMPACT WILL CLOUDS HAVE ON MAX TEMPS. FOR
PRECIP...TRIED LIMITING MENTIONABLE PRECIP TO WHERE MODELS SHOW
K-INDEX EXCEEDING 28. GOING BACK TO YESTERDAY...THIS MATCHED UP
FAIRLY WELL WITH WHERE SHOWERS/STORMS WERE ABLE TO FIRE OFF.
THOUGH MODELS DIFFER ON HOW QUICKLY THE H7 THROUGH/MOISTURE MAKE
IT THROUGH THE REGION...THEY ARE ALL FAIRLY SIMILAR WITH THEIR
K-INDEX FORECASTS...WHICH MATCHES UP WELL WITH 19.03 SREF PROBS.
HAVE HIGHEST POPS ACROSS SOUTH CENTRAL MN THIS MORNING...WITH ISO
STORMS LINGERING INTO THE AFTERNOON ALONG I-90. HOWEVER...THERE
IS SUPPORT FROM THE 19.00 ECMWF/GFS ALONG WITH HRRR REFLECTIVITY
FORECASTS FOR HAVE POPS FARTHER NORTH THAN CURRENTLY INDICATED FOR
TODAY. IF THE GFS/ECMWF ENDS UP BEING THE ROUTE THINGS TAKE FOR
TODAY...THEN IT WILL LIKELY END BEING MOSTLY CLOUDY ACROSS SOUTH
CENTRAL MN...WHERE HIGHS COULD END UP SEVERAL DEGREES COOLER THAN
CURRENTLY INDICATED.
PRECIP WILL QUICKLY CUT OFF THIS EVENING...WITH SKIES BECOMING
CLEAR. THIS WILL SET THE STAGE FOR RATHER TRANQUIL WEATHER FOR
SUNDAY THROUGH WEDNESDAY AS THE SFC HIGH SLOWLY SLIDES EAST. WITH
H5 HEIGHTS AND H85 TEMPS SLOWLY BUILDING DURING THIS PERIOD...WILL
SEE HIGHS TICK UP A COUPLE OF DEGREES EACH DAY. BY WEDNESDAY...THE
RETURN OF SOUTHERLY FLOW WILL HELP BOAST TEMPS BACK INTO THE
LOWER 80S...ALONG WITH SENDING DEWPS BACK INTO THE 60S.
FOR WEDNESDAY NIGHT THROUGH FRIDAY...UNCERTAINTY IN THE FORECAST
INCREASES QUITE A BIT. THOUGH THE MEDIUM RANGE MODELS GENERALLY
AGREE ON WEAK ZONAL FLOW SETTING UP ACROSS THE NRN CONUS THIS
PERIOD...THEY DIFFER ON THE HANDLING OF A SHORT WAVE PEGGED TO
MOVE THROUGH THIS FLOW FROM THURSDAY INTO FRIDAY. THE GFS
CONTINUES TO BE THE MOST AGGRESSIVE WITH THE WAVE...BRINGING A
NEGATIVELY TILTED SHORTWAVE AND ASSOCIATED COLD FRONT ACROSS THE
AREA THURSDAY NIGHT INTO FRIDAY. THE ECMWF SHOWS A MUCH
WEAKER/SLOWER WAVE WORKING INTO THE PLAINS...WITH VERY LITTLE IN
THE WAY OF PRECIP WORKING INTO THE AREA UNTIL THE WEEKEND FRONT.
FOR THIS PERIOD...FOLLOWED THE BLEND APPROACH WITH THE CONTINUED
MENTION OF 40-50 POPS THURSDAY NIGHT. HARD TO SAY WHICH WAY THINGS
MAY GO AT THIS POINT...BUT IT DOES APPEAR THE GFS IS SUFFERING
FROM SOME CONVECTIVE FEEDBACK WHICH IS LIKELY IMPACTING THE
STRENGTH OF SFC FEATURES IT SHOWS.
&&
.AVIATION.../12Z TAF ISSUANCE/
THE MID LEVEL CLOUD DECK CONTINUES TO EXPAND ACROSS THE AREA THIS
MORNING...AND HAS HELPED INHIBIT DENSE FOG FROM FORMING. THE MVFR
VSBYS AT KRNH AND KEAU HAVE ALSO SUBSIDED FOR THE MOST PART.
MEANWHILE...SCATTERED SPRINKLES ARE EVIDENT ON CURRENT RADAR
IMAGERY IN ASSOCIATION WITH WEAK SHORTWAVE ENERGY OVERHEAD...BUT
COVERAGE DOESN/T WARRANT A MENTION IN THE TAFS...AND NO ATTENDANT
CIG/VSBY REDUCTIONS WILL OCCUR. SCT-BKN CUMULUS CLOUDS WILL BE
POSSIBLE INTO THE AFTERNOONN HOURS...WITH EVENTUAL CLEARING AFTER
00Z. NORTHERLY WINDS AT 5-9 KTS WILL PREVAIL THROUGH THIS
AFTERNOON...AND THEN LIGHT AND VARIABLE WINDS WILL DEVELOP AFTER
0Z.
KMSP...SCT-BKN MID LEVEL DECK TO START THE PERIOD...WITH CU FIELD
DEVELOPING BY 15Z. CLEARING SKIES AFTER 00Z. NORTHERLY WINDS AT
5-8 KTS THROUGH THIS AFTERNOON...FOLLOWED BY A DECREASE TO BELOW 5
KTS.
/OUTLOOK FOR KMSP/
MON...VFR. NORTHWEST 5 TO 10 MPH.
TUE...VFR. SOUTHWEST 5 TO 10 MPH.
WED...VFR. SOUTH 5 TO 10 MPH.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LRS/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
350 AM CDT SUN AUG 19 2012
.DISCUSSION...
RATHER AMPLIFIED UPPER AIR PATTERN REMAINS IN PLACE THIS
MORNING...WITH SHARP UPPER RIDGE UP THE ROCKY MOUNTAINS FLANKED
BY A DEEP CLOSED LOW NEAR HUDSON BAY AND A LONGWAVE TROUGH OVER
THE NERN PAC. WITHIN THE NNW FLOW OVERHEAD...WATER VAPOR IMAGERY
AND RAP PV ANALYSIS SHOWS A POTENT WAVE DROPPING INTO CENTRAL MN
AT 8Z. AT THE SFC...HIGH PRESSURE WAS PARKED ACROSS MUCH OF THE
GREAT PLAINS WITH A WEAK FRONT/WIND SHIFT STILL EVIDENT IN THE FLOW
FROM MADISON...MN ACROSS THE TWIN CITIES AND OVER TOWARD GREEN
BAY.
ALOFT...PATTERN WILL UNDERGO A SLOW DE-AMPLIFICATION OVER THE
COMING DAYS. BY THE MIDDLE OF NEXT WEEK...WEAK ZONAL FLOW WILL BE
IN PLACE ACROSS MUCH OF THE CONUS AS ROCKIES RIDGE FLATTENS
OUT...THE HUDSON LOW FILLS/LIFTS NE AND THE PAC TROUGH MOVES INTO
BC AND UNDERGOES SOME DEEPENING. MEDIUM RANGE MODELS DO NOT BRING
THE WRN WAVE ACROSS THE CENTER OF THE CONTINENT UNTIL NEXT
WEEKEND.
AT THE SFC...FRONT SPLITTING THE MPX CWA NEARLY IN HALF THIS
MORNING WILL SLOWLY WASH OUT DURING THE DAY AS HIGH PRESSURE ACROSS
THE DAKOTAS PUSHES EAST. THIS HIGH PRESSURE WILL THEN SLOWLY TRACK
ACROSS THE UPPER MS VALLEY THROUGH TUESDAY NIGHT. WEDNESDAY...A
WEAK FRONTAL BOUNDARY WILL TRY TO SAG INTO THE LAKE SUPERIOR
REGION AS A LEE THROUGH SLOWLY TAKES SHAPE ACROSS THE HIGH PLAINS AS
UPPER FLOW BECOMES MORE ZONAL. THE FIRST FRONTAL PUSH FROM THIS
LEE TROUGHING LOOKS TO TRY AND PUSH INTO THE MPX AREA
THU/FRI...WITH A MORE SIGNIFICANT FRONT NOT LIKELY TO ARRIVE UNTIL
NEXT WEEKEND WITH THE STRONGER UPPER FORCING.
FOR TODAY THERE ARE TWO CONCERNS THANKS TO SHORTWAVE NOW IN
CENTRAL MN. FIRST IS HOW FAR NORTH TO KEEP POPS TODAY...WHILE THE
SECOND IS WHAT IMPACT WILL CLOUDS HAVE ON MAX TEMPS. FOR
PRECIP...TRIED LIMITING MENTIONABLE PRECIP TO WHERE MODELS SHOW
K-INDEX EXCEEDING 28. GOING BACK TO YESTERDAY...THIS MATCHED UP
FAIRLY WELL WITH WHERE SHOWERS/STORMS WERE ABLE TO FIRE OFF.
THOUGH MODELS DIFFER ON HOW QUICKLY THE H7 THROUGH/MOISTURE MAKE
IT THROUGH THE REGION...THEY ARE ALL FAIRLY SIMILAR WITH THEIR
K-INDEX FORECASTS...WHICH MATCHES UP WELL WITH 19.03 SREF PROBS.
HAVE HIGHEST POPS ACROSS SOUTH CENTRAL MN THIS MORNING...WITH ISO
STORMS LINGERING INTO THE AFTERNOON ALONG I-90. HOWEVER...THERE
IS SUPPORT FROM THE 19.00 ECMWF/GFS ALONG WITH HRRR REFLECTIVITY
FORECASTS FOR HAVE POPS FARTHER NORTH THAN CURRENTLY INDICATED FOR
TODAY. IF THE GFS/ECMWF ENDS UP BEING THE ROUTE THINGS TAKE FOR
TODAY...THEN IT WILL LIKELY END BEING MOSTLY CLOUDY ACROSS SOUTH
CENTRAL MN...WHERE HIGHS COULD END UP SEVERAL DEGREES COOLER THAN
CURRENTLY INDICATED.
PRECIP WILL QUICKLY CUT OFF THIS EVENING...WITH SKIES BECOMING
CLEAR. THIS WILL SET THE STAGE FOR RATHER TRANQUIL WEATHER FOR
SUNDAY THROUGH WEDNESDAY AS THE SFC HIGH SLOWLY SLIDES EAST. WITH
H5 HEIGHTS AND H85 TEMPS SLOWLY BUILDING DURING THIS PERIOD...WILL
SEE HIGHS TICK UP A COUPLE OF DEGREES EACH DAY. BY WEDNESDAY...THE
RETURN OF SOUTHERLY FLOW WILL HELP BOAST TEMPS BACK INTO THE
LOWER 80S...ALONG WITH SENDING DEWPS BACK INTO THE 60S.
FOR WEDNESDAY NIGHT THROUGH FRIDAY...UNCERTAINTY IN THE FORECAST
INCREASES QUITE A BIT. THOUGH THE MEDIUM RANGE MODELS GENERALLY
AGREE ON WEAK ZONAL FLOW SETTING UP ACROSS THE NRN CONUS THIS
PERIOD...THEY DIFFER ON THE HANDLING OF A SHORT WAVE PEGGED TO
MOVE THROUGH THIS FLOW FROM THURSDAY INTO FRIDAY. THE GFS
CONTINUES TO BE THE MOST AGGRESSIVE WITH THE WAVE...BRINGING A
NEGATIVELY TILTED SHORTWAVE AND ASSOCIATED COLD FRONT ACROSS THE
AREA THURSDAY NIGHT INTO FRIDAY. THE ECMWF SHOWS A MUCH
WEAKER/SLOWER WAVE WORKING INTO THE PLAINS...WITH VERY LITTLE IN
THE WAY OF PRECIP WORKING INTO THE AREA UNTIL THE WEEKEND FRONT.
FOR THIS PERIOD...FOLLOWED THE BLEND APPROACH WITH THE CONTINUED
MENTION OF 40-50 POPS THURSDAY NIGHT. HARD TO SAY WHICH WAY THINGS
MAY GO AT THIS POINT...BUT IT DOES APPEAR THE GFS IS SUFFERING
FROM SOME CONVECTIVE FEEDBACK WHICH IS LIKELY IMPACTING THE
STRENGTH OF SFC FEATURES IT SHOWS.
&&
.AVIATION... /06Z TAF ISSUANCE/
SHOWERS WILL SLOWLY DIMINISH EARLY THIS MORNING AS A COLD FRONT
FROM NORTHERN WI THROUGH CENTRAL MN MOVES SOUTHWARD. KRWF...KMSP
AND KEAU WILL HAVE A SHOWER AND ISOLATED THUNDERSTORM THREAT FOR
A FEW MORE HOURS. CLEARING OVER NORTHERN MN WILL BEGIN TO WORK
INTO KAXN...KSTC AND KRNH AFTER 08Z. THERE WILL LIKELY BE FOG
DEVELOPMENT AT KSTC AND KRNH WITH MVFR OR LOWER VISIBILITY.
CONCERN IS GROWING FOR IFR OR LOWER CEILINGS DEVELOPING. KEAU MAY
BE IN TROUBLE AS WELL BUT IT MAY BE TOWARDS DAYBREAK. HIGH
PRESSURE AND LIGHT NORTHERLY WINDS WILL OCCUR ON SUNDAY. THE CU
RULE IS RATHER NEGATIVE IN THE MORNING FROM KMSP THROUGH KEAU AND
HAVE INDICATED SOME BKN050 FOR KEAU WITH SCT050 FOR SITES TO THE
WEST.
KMSP...
A FEW SHOWERS ARE POSSIBLE THROUGH 08Z. CEILINGS BKN-OVC080-100
WILL LAST TO NEAR DAYBREAK THEN DIMINISH. SCT-BKN040 DEVELOPING
SUNDAY MORNING WITH CLR-SCT050 IN THE AFTERNOON. LIGHT NORTHWEST
WINDS DEVELOPING OVERNIGHT WITH NORTH WINDS 6 TO 9 KNOTS ON SUNDAY.
/OUTLOOK FOR KMSP/
MON...VFR. NORTHWEST 5 TO 10 MPH.
TUE...VFR. SOUTHWEST 5 TO 10 MPH.
WED...VFR. SOUTH 5 TO 10 MPH.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/RAH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1133 PM CDT SAT AUG 18 2012
.AVIATION...
06Z TAFS FOR KOMA...KLNK AND KOFK.
MID LEVEL CLOUDS AROUND 7000 TO 10000 FEET WILL CONTINUE TO MOVE
AWAY FROM KOMA AND KLNK OVERNIGHT. DUE TO LIGHT WINDS AND WET
GROUND FROM AREAS OF RAIN SATURDAY...AREAS OF FOG SHOULD DEVELOP.
THIS WOULD MAINLY BE AT KOMA AND KOFK...WHERE HAVE VISIBILITIES
TEMPORARILY GOING DOWN TO 3-4 MILES TOWARD SUNRISE. FOG SHOULD
BURN OFF BEFORE 15Z. ANOTHER WEAK DISTURBANCE IN THE FLOW WILL
DROP DOWN TOWARD THE AREA SUNDAY. THIS SHOULD CAUSE AN INCREASE
IN MID LEVEL CLOUDINESS. AT THIS TIME...FELT ANY SHRA WOULD NOT
AFFECT ANY OF THE TAF SITES.
MILLER
&&
.PREV DISCUSSION... /ISSUED 316 PM CDT SAT AUG 18 2012/
DISCUSSION...
SCATTERED SHOWERS CONTINUE TO SLIDE SOUTHEAST AS FORCING FOR
ASCENT FROM A MID LEVEL SHORTWAVE CONTINUES TO MOVE SOUTHEAST THRU
THE FORECAST AREA. THERE IS ANOTHER AREA OF SHOWERS IN A BAND TO
THE NORTHEAST OF THE CWA WHICH SEEMS TO LINE UP WELL WITH A NARROW
BAND OF MID LEVEL FRONTOGENESIS ON NOSE OF THETA-E AXIS. THIS
IS FORECAST TO CONTINUE SOUTHEAST THRU THE LATE AFTERNOON AND
EVENING HOURS SO WL CONTINUE TO INCLUDE A SMALL MENTION OF POPS IN
OUR EASTERN COUNTIES FOR THIS ACTIVITY AS WELL. IN
ADDITION...THERE IS A POTENTIAL FOR FOG DEVELOPMENT OVERNIGHT WITH
CLEARING SKIES. SFC WIND BECOMES LIGHT AND VARIABLE AS HIGH
PRESSURE MOVES OVER AREAS THAT SAW SOME PRECIPITATION TODAY.
LATEST HRRR ALSO SHOWING AREA OF REDUCED VISIBILITIES...ESPECIALLY
IN OUR NORTH SO WL GO AHEAD AND MENTION SOME PATCHY FOG OVERNIGHT.
EXPECTING LOWS TO FALL INTO THE UPPER 40S TO LOWER 50S WHICH
WILL BE CLOSE BUT SLIGHTLY ABOVE RECORDS.
SUNDAY CONTINUES TO LOOK MOSTLY DRY AS HIGH PRESSURE SLIDES EAST OF
THE AREA. MODELS CONTINUE TO INDICATE SOME LIGHT QPF IN OUR EASTERN
COUNTIES ASSOCIATED WITH EXITING UPPER LEVEL SHORTWAVE ENERGY. MAY
HAVE SOME ISOLATED SHOWERS OVER IOWA COUNTIES IN THE AFTERNOON
ONCE CU FIELD DEVELOPS. WILL THROW IN A SLIGHT CHANCE POP IN OUR
FAR NERN COUNTIES FOR SUNDAY AFTERNOON AND MENTION ISOLATED
THUNDER AS SOME INSTABILITY IS PRESENT.
AREA REMAINS IN NORTHWESTERLY FLOW FOR EARLY IN THE SCHOOL/WORK
WEEK. THE WEATHER SHOULD REMAIN FAIRLY QUIET WITH WARM SOUTHERLY
FLOW BRINGING A SLIGHT INCREASE IN LOW LEVEL MOISTURE TO THE
AREA.
IN THE EXTENDED...MID LEVEL FLOW WILL BECOME MORE ZONAL BY MID
WEEK AS WEAKENING UPPER LEVEL RIDGE FLATTENS OVER THE NATIONS MID
SECTION. A POTENT SHORTWAVE MOVING INTO THE NORTHERN PLAINS BY
LATE IN THE WEEK WILL DRIVE A COOL FRONT THRU THE CENTRAL PLAINS.
AHEAD OF THIS BOUNDARY...LOW LEVEL WARM AIR AND MOIST ADVECTION
COULD LEAD TO A SCATTERED CHANCE OF SHOWERS AND THUNDERSTORMS
THURSDAY. SEVERE THREAT WOULD LIKELY REMAIN FAR TO OUR
NORTH...CLOSER TO POTENT SHORTWAVE ENERGY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ELKO NV
320 PM PDT SUN AUG 19 2012
.SYNOPSIS...MONSOON MOISTURE WILL CONTINUE TO PRODUCE SCATTERED
THUNDERSTORMS ACROSS NEVADA THROUGH THIS EVENING. DRIER AIR
ARRIVES IN NORTHERN NEVADA ON MONDAY...RESTRICTING THUNDERSTORM
COVERAGE TO AREAS SOUTH OF HIGHWAY 50. A SIGNIFICANT ROUND OF
THUNDERSTORMS IS EXPECTED ACROSS EASTERN NEVADA TUESDAY AFTERNOON
AND EVENING.
&&
.SHORT TERM...TONIGHT THROUGH TUESDAY. THUNDERSTORMS PRETTY MUCH
FOLLOWING THE EXPECTED SCRIPT THIS AFTERNOON...FAVORING THE
WESTERN AND SOUTHERN ZONES. INSTABILITY IS STRONGEST ACROSS HUMBOLDT
AND WHITE PINE COUNTIES...AND THESE ARE THE AREAS THAT WILL SEE
THE STRONGEST CONVECTION INTO THIS EVENING. EXPECT SHOWER AND
THUNDERSTORMS TO CONTINUE THROUGH THE EARLY EVENING...AS SHOWN BY
12/18Z NAM AND HRRR SOLUTIONS. WITH PRECIPITABLE WATER NEAR OR
ABOVE 1 INCH...AND K INDEX NEAR 40 WILL MAINTAIN FLASH FLOOD WATCH
FOR CENTRAL NEVADA THROUGH 8 PM. KLRX REFLECTIVITY INDICATES
HEALTHY NE MOVEMENT WITH THE STORMS...BUT WITH SUCH HIGH MOISTURE
CONTENT AND THE POTENTIAL FOR TRAINING ECHOES...WILL LET THE FLASH
FLOOD WATCH CONTINUE. ATMOSPHERE IS PLENTY MOIST...BUT RATHER
LIMITED ON INSTABILITY. REACHING CONVECTIVE TEMPERATURES HAS BEEN
DELAYED SOMEWHAT BY CLOUDS/SHOWERS/MORE STABLE AIR...BUT FEEL
CONVECTION WILL EXPAND INTO THE EVENING. STRONG STORMS AND LOCAL
FLOODING POSSIBLE. EXPECT THUNDERSTORM COVERAGE TO QUICKLY WANE
AFTER SUNSET AS USUAL.
MONDAY...SHORTWAVE RIDGE QUICKLY BUILDS OVER NEVADA...AND MUCH
DRIER AIR INVADES THE NORTHERN ZONES. PW FALLS TO WELL BELOW 0.50
INCH ACROSS ELKO COUNTY. THUNDERSTORM COVERAGE WILL BE RESTRICTED
TO ISOLATED MONDAY...AND CONFINED TO AREAS SOUTH OF U.S. HIGHWAY
50. THE REST OF US MOSTLY SUNNY AND HOT...WITH HIGHS IN THE LOWER
TO MID 90S.
MONDAY NIGHT...MONSOON MOISTURE SURGES QUICKLY NORTHWARD OVERNIGHT
BEHIND DEPARTING RIDGE AXIS...AND AHEAD OF TROUGH APPROACHING FROM
THE WEST. INCREASED CLOUDS AND SHOWER COVERAGE OVERNIGHT...WITH
VERY MILD LOW TEMPERATURES IN THE UPPER 50S AND LOWER 60S TUESDAY
MORNING.
TUESDAY...ACTIVE THUNDERSTORM DAY EXPECTED AHEAD OF APPROACHING
TROUGH...BUT ONLY ACROSS EASTERN NEVADA. MODELS CONTINUE TO
DEPICT AN EXTREMELY TIGHT MOISTURE GRADIENT ACROSS NEVADA...WITH
PW RANGING FROM 1.17 INCH NEAR WENDOVER...DOWN TO LESS THAN 0.25
INCH NEAR WINNEMUCCA. SCATTERED TO NUMEROUS THUNDERSTORMS EXPECTED
TO DEVELOP OVER EASTERN NEVADA /PRIMARILY ELKO AND WHITE PINE
COUNTIES/ TUESDAY AFTERNOON...AHEAD OF A QUASI-DRYLINE THAT WILL
BISECT THE CWA AT PEAK HEATING. CAPE AND BULK SHEAR VALUES WILL
ORGANIZE CONVECTION ACROSS EASTERN NEVADA...AND JET DYNAMICS FROM
APPROACHING TROUGH WILL HELP AS WELL. WITH THE CONSISTENCY IN
MODEL SOLUTIONS...WENT AHEAD AND ADDED WIND/HAIL WORDING TO THE
ZONES FOR EASTERN NEVADA TUESDAY. WESTERN NEVADA BONE DRY IN THE
DRY SLOT...WITH A VERY TIGHT GRADIENT IN THE POP GRIDS. EXPECT
SW TO W WINDS TO INCREASE TO AT LEAST BREEZY LEVELS...AS 700 MB
WINDS INCREASE TO NEAR 20 KTS. BT
.LONG TERM...TUESDAY NIGHT THROUGH NEXT SUNDAY. GENERAL AGREEMENT IN
THE MODELS THROUGH THE PERIOD...WITH JUST SOME SUBTLE DIFFS LATE IN
THE WEEK. OVERALL...DRYING AND A LITTLE COOLING...AT LEAST NOT IN
THE UPPER 90S ANY MORE. PERIOD BEGINS WITH THE LEFT OVERS OF THE
SERIOUS TROUGH ON TUESDAY MOVING OUT...AND SOME RESIDUAL CONVECTION
SMACK ALONG THE UTAH LINE TUESDAY NIGHT. BY WEDNESDAY MORNING THE
AIR MASS HAS DRIED OUT. A VERY WEAK QUASI-MONSOONAL PUSH OCCURS
EARLY THURSDAY BUT THE MODELS HAVE IT GETTING ONLY TO SOUTHEAST
WHITE PINE COUNTY. SOME LITTLE INSTABILITY THERE SO KEPT CONVECTION
IN A LIMITED AREA THERE. BY THURSDAY NIGHT THE ATMOSPHERE DRIES OUT
FURTHER AND THERE ARE VERY LOW TO ZERO POPS THE REST OF THE PERIOD.
ANOTHER LITTLE SHORT WAVE WITH ASSOCIATED SURFACE WIND SHIFT LATE
THURSDAY/EARLY FRIDAY WHICH WILL KEEP HIGHS IN THE UPPER 80S OR LOW
90S OVER MOST OF THE AREA. LOWS WILL BE IN THE 40S AND 50S...WITH A
FEW 30S OVER HIGHER TERRAIN...ESPECIALLLY IN THE NORTH. BB
&&
.AVIATION...CONVECTION WILL BEGIN TO WEAKEN WITH SUNSET OVER THE
GREAT BASIN AND STORMS WILL BECOME ISOLATED AT BEST AFTER 06Z. A FEW
SHOWERS WILL STILL AFFECT CENTRAL AND EASTERN NEVADA THROUGH 12Z.
WILL KEEP VCTS AT KWMC...KTPH...AND KELY...AND VCSH AT KEKO THROUGH
03Z. WILL KEEP VCSH AT KELY THROUGH 06Z. WINDS WILL DROP TO
UPSLOPE/DOWN VALLEY AND LIGHT SPEEDS. BB
&&
.FIRE WEATHER...SCATTERED THUNDERSTORMS ACROSS THE FIRE DISTRICT
THROUGH SUNSET THIS EVENING. ELEVATED LAL...BUT MOST STORMS WILL
PRODUCE ENOUGH RAINFALL TO LIMIT NEW LIGHTNING IGNITIONS.
MONDAY...DRIER AIR ACROSS THE NORTHERN FWZ. THUNDERSTORM COVERAGE
WILL BE LIMITED TO ISOLATED...AND CONFINED TO AREAS SOUTH OF U.S.
HIGHWAY 50.
TUESDAY...SCATTERED TO NUMEROUS THUNDERSTORMS EXPECTED ACROSS
EASTERN NEVADA...PRIMARILY FWZ 455...469...470. STRONG STORMS WITH
GUSTY ERRATIC OUTFLOW WINDS ARE POSSIBLE. BT
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM PDT THIS EVENING FOR NORTHEASTERN
NYE COUNTY...NORTHWESTERN NYE COUNTY...SOUTHERN LANDER COUNTY
AND SOUTHERN EUREKA COUNTY...WHITE PINE COUNTY.
&&
$$
99/98/98/99
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
946 PM EDT MON AUG 20 2012
.SYNOPSIS...
A WEAK FRONTAL SYSTEM WILL KEEP SCATTERED LIGHT SHOWERS OVER THE
WESTERN CATSKILLS AND POCONOS UNTIL MIDNIGHT. HIGH PRESSURE WILL
FOLLOW BEHIND THE FRONT, BRINGING MOSTLY DRY WARM WEATHER TOMORROW
THROUGH THE REST OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
945 PM UPDATE...LIGHT SHOWERS CURRENTLY CONFINED TO THE WESTERN
CATSKILLS AND POCONOS. THIS ACTIVITY CONTINUES TO SHIFT OFF TO THE
EAST WITH THE MID LEVEL SHORT WAVE THAT IS FORCING IT. WILL
KEEP MENTION OF LIGHT SHOWERS HERE UNTIL AROUND MIDNIGHT THEN DRY
CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE OVERNIGHT PERIOD.
SKIES WILL BECOME PARTLY TO MAINLY CLEAR BEHIND SHORT WAVE AND
WITH MOIST GROUND AND WEAK MIXING INCLUDED PATCHY VALLEY FOG
ACROSS THE TWIN TIERS LATE TONIGHT INTO THE EARLY MORNING HOURS.
615 PM UPDATE...NUMEROUS SHOWERS CONTINUE OVER THE WYOMING VALLEY
NORTHEAST ACROSS THE POCONOS INTO THE SOUTHERN CATSKILLS, WITH
SCATTERED ACTIVITY BACK ACROSS CENTRAL NEW YORK. THIS CONVECTION
IS BEING FORCED BY A MID LEVEL SHORT IN SOUTHWEST UPPER LEVEL
FLOW. AS THIS FEATURE CONTINUES MOVING NORTHEAST THIS EVENING THE
ACTIVITY WILL GRADUALLY DIMINISH. TEMPS HAVE COOLED RAPIDLY LATE
THIS AFTERNOON DUE TO THE SHOWERY WEATHER, READINGS NOW ARE
GENERALLY IN THE MID TO UPPER 60S. SHORT TERM ADJ TO
TEMPS/CLOUDS/POPS, REST UNCHANGED.
.PREVIOUS DISC...
LATEST WATER VAPOR LOOP CONFIRMS A WEAK SHORT WAVE TRACKING
NORTHEAST FROM THE MID-ATLANTIC STATES TOWARD NEW ENGLAND THIS
AFTERNOON. A BROKEN BAND OF SHOWERS WITH ISOLATED THUNDER HAS
DEVELOPED ACROSS EASTERN PA NORTHEAST TO THE CATSKILLS THIS
AFTERNOON... AND THIS WILL TRACK SLOWLY EAST ACROSS OUR
SOUTHEASTERN COUNTIES THROUGH THIS EVENING. MEANWHILE A FEW
SCATTERED TO ISOLATED SHOWERS WILL PERSIST FARTHER TO THE WEST
UNDER THE UPPER TROUGH THROUGH EARLY THIS EVENING. CURRENT
FORECAST REFLECTS THIS SCENARIO WITH LIKELY POPS FOR NORTHEAST PA
AND THE CATSKILLS INTO EARLY THIS EVENING... AND CHANCE POPS
FARTHER WEST. SEVERE THREAT WITH ANY THUNDERSTORM INTO THIS
EVENING LOOKS VERY LOW WITH WEAK WIND FIELDS AND LATEST RUC SHORT
TERM FORECASTS INDICATING CAPE VALUES GENERALLY LESS THAN 300
J/KG. RAINFALL THUS FAR WITH THESE SHOWERS HAS BEEN LESS THAN AN
INCH AND WITH THE PROGRESSIVE NATURE OF THESE SHOWERS OBSERVED SO
FAR TODAY AM NOT EXPECTING ANY EXCESSIVE RAINFALL INTO THIS
EVENING.
EXPECT AREAS OF FOG AND STRATUS TO FORM LATER TONIGHT WITH SOME
CLEARING AND PLENTY OF LOW-LEVEL MOISTURE LEFT OVER FROM TODAYS
SHOWERS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY LOOKS LIKE A LESS CONVECTIVELY ACTIVE DAY THAN TODAY WITH
SLIGHT DRYING BEHIND TODAY`S SYSTEM RESULTING IN LITTLE IF ANY
INSTABILITY ON AREA FORECAST SOUNDINGS. HOWEVER STILL CAN`T RULE
OUT AN ISOLATED SHOWERS GIVEN THAT THE UPPER TROUGH WILL REMAIN
JUST TO THE WEST THROUGH THE DAY. BASED ON THIS HAVE GONE WITH
POPS GENERALLY FROM 15 TO 25 PERCENT TUESDAY AFTERNOON. FEWER
CLOUDS IN MOST PLACES WILL RESULT IN SLIGHTLY WARMER
TEMPERATURES... ESPECIALLY ACROSS THE TWIN TIERS WHERE CLOUDS KEPT
TEMPERATURES DOWN QUITE A BIT TODAY. EXPECT HIGHS MAINLY NEAR OR
JUST ABOVE 80.
QUIET PATTERN CONTINUES TUESDAY NIGHT THROUGH THURSDAY AS HIGH
PRESSURE SETTLES IN ACROSS THE AREA. CONDITIONS WILL BE DRY WITH
AMPLE DAYTIME SUNSHINE... HIGH TEMPERATURES NEAR OR JUST ABOVE 80
AND LOWS MOSTLY IN THE 50S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
2 PM TUE UPDATE...
A RIDGE OF HIGH PRESSURE SFC AND ALOFT ALONG THE EAST COAST WILL
BE IN CONTROL FOR MOST OF THE EXTENDED. TIMING DIFFERENCES ON WHEN
THIS WILL BREAK DOWN ENOUGH TO LET SHOWERS AND THUNDERSTORMS FORM
DURING THE WEEKEND. LATER A COLD FRONT WILL MOVE THROUGH TUESDAY.
THE GFS IS FASTER BY 12 TO 24 HOURS OVER THE EURO.
TEMPERATURES START NEAR NORMAL THEN RISE TO BE ABOVE NORMAL FOR
THE WEEKEND AND NEXT WEEK. FOLLOWED HPC GUIDANCE.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
A COMBINATION OF LIGHT WIND FLOW AND MOIST ANTECEDENT CONDITIONS
WILL LEAD TO PATCHY FOG EARLY TUESDAY MORNING. THE BEST CHANCE FOR
FOG AT A LOCAL TERMINAL WILL BE AT ELM, WHERE TEMPO 1/2SM FOG IS
FORECAST BETWEEN 8Z AND 12Z.
THERE IS A LOWER CHANCE FOR IFR FOG AT BGM. IF FOG DEVELOPS, IT
IS LIKELY THE VIS RESTRICTION WILL BE IN THE 1SM TO 3SM RANGE WITH
A BROKEN 600-900FT DECK OVERHEAD.
LIGHT WINDS AND VFR CONDITIONS ARE FORECAST FOR TUESDAY AFTERNOON.
THERE IS A SLIGHT CHANCE FOR A THUNDERSTORM NEAR AVP, BUT THE ODDS
ARE VERY LOW THAT THE TERMINAL WILL BE DIRECTLY AFFECTED.
OUTLOOK...
TUE NGT TO SAT...MAINLY VFR. MRNG VLY IFR FOG PSBL AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE/RRM
NEAR TERM...MSE/RRM
SHORT TERM...MSE
LONG TERM...TAC
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
211 PM EDT SUN AUG 19 2012
.SYNOPSIS...
A SLOW MOVING FRONT...IN COMBINATION WITH AN UPPER LEVEL
DISTURBANCE...WILL BRING THE CHANCE FOR SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION LATER TONIGHT INTO MONDAY EVENING. HIGH
PRESSURE WILL BUILD INTO THE REGION STARTING ON TUESDAY WITH FAIR
WEATHER EXPECTED FOR MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SFC ANYLS SHOWS A CDFNT ACRS LOWER ONTARIO INTO CNTRL MI WITH AN
INVERTED TROF DVLPNG OVER ERN OH/WRN PA. AT UPR LVLS...THE DEEP TROF
OVER THE ERN U.S. WILL GRADUALLY LIFT NEWD/PULL OUT...WITH MDLS
SUGGESTING THE CDFNT/INVERTED TROF WILL EVENTUALLY MERGE AND WORK EWD
ACRS THE BGM FCST AREA ON MON...AS LOW PRES TRACKS NEWD OFF THE MID
ATLC CST. THE MAIN TROF AXIS WON`T PASS THE FCST AREA TIL
WED....WITH UPR FLOW BCMG GNRLY ZONAL BY WED EVNG.
GRADUAL MOISTENING WILL OCCUR OVRNGT AS SRLY FOW DVLPS AHEAD OF THE
SFC TROF/FNT. SHORT RNG MESO MDLS INCLUDING THE RUC AND LCL WRF SUGGEST
THAT ACTIVITY ACRS CNTRL PA COULD TRACK NWD INTO THE CNTRL SRN
TIER THIS EVNG ALONG AND EAST OF THE SFC TROF...AND HINTS THAT
ADDNL ISOLD/WDLY SCT DVLPMNT IS PSBL...SO WE INDICATE LOW CHC POPS
SPREADING N AND NE ACRS THE FCST AREA OVRNGT.
ANOTHER S/WV IS FCST TO APRCH THE RGN TMRW AFTN...AND THIS IN
COMBINATION WITH THE SFC BNDRY SHUD HELP TO FOCUS ACTIVITY ACRS
CNTRL/ERN ZONES ON MON AFTN. CHCS FOR TSRA WILL BE ON THE LOW SIDE
GIVEN LIMITED INSTABILTY. TEMPS COULD BE TRICKY ON MON...FOR NOW
INDICATED COOLEST MAXES ACRS SE ZONES (A70 OR L70S).
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
SHRA ARE XPCTD TO DIMINISH/MOV OUT ON MON EVNG. MDLS SUGGEST
POTNL FOR ISOLD ACTIVITY FAR SRN TIER AND NE PA ON TUE AND PSBLY WED.
OVERALL THE PTRN DOES NOT LOOK AS FVRBL FOR DIURNAL CONVECTIVE
DVLPMNT AS SFC HI PRES WILL BE BUILDING INTO THE RGN...AND
INSPECTION OF 12Z NAM/GFS PROFILES SHOWS VERY LIMITED CAPE SO
WILL LOWER POPS TO SLGT CHC THESE AREAS FOR TUE/WED AFTN. OTRW...NICE
WX WITH SEASONABLE TEMPS AND PS DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
SUBTLE FEATURES WILL INFLENCE THE WX IN THE LONG TERM AS THE SFC
RDGG BRKS DOWN EARLY IN THE PD. OPERATIONAL MODELS SHOW A WEAK FNTL
BNDRY TRYING TO DROP SOUTH FROM CANADA FRI INTO SAT BEFORE
EVENTUALLY WASHING OUT OVER THE AREA. WITH HTG...THIS MAY BE ENUF
LL CONV TO DVLP ISLTD AFTN CONV FRI AND SAT.
TEMPS WILL SHOW A GRADUAL RECOVERY THRU THE PD...RCHG ABV NRML BY
FRI AND SAT. STILL DFRNCS BETWEEN HPC GUID AND GFS GENERATED
MEX...SO BLENDED GUID WITH PRVS FCST TO CONT A SLOW UPWARD TREND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
FCST AREA CAUGHT BETWEEN A COLD FNT APRCHG THRU THE UPR LAKES AND
A WV MVG UP THE EAST CST. THIS WILL LEAD TO A GRADUAL INCRS IN
CLDS...ALTHOUGH CIGS WILL REMAIN VFR THRU AT LEAST 12Z MON. BY
THEN...CONV LL FLOW WILL DVLP SHWRS LWRG CIGS AND VSBY INTO THE
MVFR RANGE THRU THE END OF THE PD.
WITH THE APRCHG SYSTEMS SLOWING AS THEY NEAR...WINDS WILL BE
VRBL...BUT GNRLY LGT IN THE WEK GRADIENT.
OUTLOOK...
MON AFTN/TUE...SCT MVFR PSBL IN AFTN SHRA/TSRA.
WED/THU/FRI...MAINLY VFR. MRNG VLY FOG PSBL WITH IFR AT ELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
LONG TERM...DGM
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
957 PM EDT MON AUG 20 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PARKED OVER THE MISSISSIPPI VALLEY WILL
CONTINUE TO BRING COOLER AND MORE UNSETTLED WEATHER TO THE AREA
THROUGH THE END OF THE WEAK BEFORE HIGHER PRESSURE MOVES IN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 950 PM MONDAY...
DEEP L/W TROUGH ALOFT CONTINUES TO ALLOW MID/UPPER MOISTURE TO
STREAM INTO THE AREA THIS EVENING... RESULTING IN MOSTLY CLOUDY TO
OVERCAST SKIES. AT THE SURFACE A WEAK SURFACE FRONT/TROUGH CONTINUES
TO LINGER ACROSS COASTAL PORTIONS OF NC EXTENDING SOUTHWESTWARD INTO
THE GULF COAST STATES... WITH A MORE SIGNIFICANT AIR MASS CHANGE
ACROSS THE REGION (AT OUR LATITUDE) REMAINING GENERALLY ALONG AND
WEST OF THE MOUNTAINS. CONVECTION HAS GENERALLY REMAINED TO OUR EAST
INVOF THE WEAK FRONTAL ZONE AND TO OUR WEST WHERE CONVECTION
ORIGINATED OVER THE HIGHER TERRAIN AND HAS MOVED SLOWLY EASTWARD.
HOWEVER... SOME OF THE SHOWERS AND STORMS WHICH ORIGINATED OVER THE
HIGHER TERRAIN ARE NOW MAKING MOVING INTO OUR NORTHWEST PIEDMONT.
EXPECT THIS CONVECTION TO BEGIN TO WANE AS IT CONTINUES TO SLOWLY
MOVE EASTWARD ACROSS THE NORTHWEST PIEDMONT OVER THE NEXT HOUR OR
SO... GIVEN LACK OF OVERALL INSTABILITY (~500 MLCAPE AND AROUND 500
MUCAPE)... WHICH IS GENERALLY SUPPORTED BY HIRES MODELS. DO NOT
EXPECT ANY OF THIS ACTIVITY TO BE SEVERE GIVEN THE LACK OF
INSTABILITY AND CURRENT RADAR TRENDS. EXPECT THE STRONGEST STORMS
(IF ANY) COULD PRODUCE 30-35 MPH WIND GUSTS AND VERY SMALL HAIL.
THUS... HAVE REMOVED MENTION OF SEVERE STORMS FROM THE DAY ONE
SECTION OF THE HWO. HOWEVER... WE MAY SEE SOME SHOWERS AND PERHAPS
ISOLATED STORMS MOVE INTO SOUTHERN/SOUTHEASTERN PORTIONS OF THE AREA
TONIGHT AS ANOTHER IMPULSE ALOFT AND WEAK SURFACE WAVE TRACK ALONG
THE WEAK FRONT/TROUGH (GENERALLY AFTER MIDNIGHT). THIS IS SUPPORTED
BY THE LATEST RAP AND SOMEWHAT BY THE LAST FEW RUNS OF THE HRRR.
THUS... WILL BUMP POPS UP IN THE SOUTHEAST TO CHANCE GENERALLY AFTER
05/06Z OR SO. THINK WE WILL HAVE ENOUGH MID/HIGH LEVEL MOISTURE
ACROSS THE AREA TO SEE TOO MUCH FOG. THUS... WILL JUST MENTION
PATCHY FOG... WITH LOW STRATUS DEVELOPING/MOVING INTO THE AREA
OVERNIGHT. EXPECT OVERNIGHT LOWS TO GENERALLY BE IN THE MID TO UPPER
60S. -BSD
FOR TUESDAY THE CHANCES FOR SEVERE WEATHER FOR TOMORROW AFTERNOON
WILL BE A BIT BETTER WITH MORE INSTABILITY AVAILABLE BUT IT WILL BE
CONFINED TO EASTERN PORTIONS OF THE CWA AND SHOULD STILL BE
ISOLATED. SHEAR WILL STILL BE PLENTIFUL AS THE JET CONTINUES TO MAKE
AN EXIT TO THE NORTHEAST. DURING THE AFTERNOON HOURS A 500 MB VORT
MAX SHOULD MAKE HEADWAY UP THE COAST BUT WHETHER OR NOT THIS FEATURE
PASSES CLOSE ENOUGH TO THE EASTERN PERIPHERY TO HELP SUPPORT
CONVECTION REMAINS TO BE SEEN. SURFACE HIGH PRESSURE TO THE
NORTHWEST WILL START TO WORK INTO THE AREA...POTENTIALLY CONFINING
CONVECTION EVEN FURTHER TO THE EAST DEPENDING ON PROGRESS. WHILE THE
UPPER LEVEL TROUGH WILL STILL BE IN PLACE IT WILL BEGIN TO LIFT OUT
AS THE UPPER JET CONTINUES UP THE EASTERN SEABOARD. MAX TEMPERATURES
TUESDAY WILL BE IN THE LOWER 80S WITH LOWS TUESDAY NIGHT IN THE MID
60S. -ELLIS
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
THE LATEST 12Z MODEL GUIDANCE INDICATES SHORTWAVE ENERGY DIGGING
SOUTHEAST THROUGH THE CENTRAL PLAINS ON TUE...AND INTO THE LOWER MS
RIVER VALLEY/DEEP SOUTH ON WED...PROGRESSING EASTWARD INTO THE
SOUTHEAST STATES WED NIGHT...WITH A LOW-LEVEL TROUGH (OR WEAK
SFC-H85 LOW) DOWNSTREAM OVER THE EASTERN CAROLINAS. A SHEAR AXIS IS
EXPECTED TO EXTEND SW-NE ALONG THE APPALACHIANS IN BOTH WED/WED
NIGHT...PROGRESSING SLOWLY EASTWARD TOWARD THE CENTRAL CAROLINAS/VA.
UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF UPSTREAM SHORTWAVE
ENERGY...LENDING UNCERTAINTY TO THE LOW-LEVEL PATTERN OVER THE
CAROLINAS WED/WED NIGHT. AS A RESULT...A FAIR AMOUNT OF UNCERTAINTY
IS PRESENT WITH TEMPERATURES...CLOUD COVER AND PRECIPITATION
CHANCES...ESPECIALLY DURING THE DAY WED. HOWEVER...MODEL GUIDANCE IS
IN RELATIVELY GOOD AGREEMENT ON THE OVERALL PATTERN...WHICH WOULD
SUGGEST MORE CLOUD COVER...COOLER TEMPERATURES AND BETTER CHANCES
FOR SHOWER ACTIVITY IN EASTERN PORTIONS OF THE AREA. WILL INDICATE
PRECIP CHANCES RANGING FROM 20-40% ON WED (HIGHEST EAST)...WITH
HIGHS IN THE MID 80S WEST TO NEAR 80F EAST. FOR WED NIGHT...MODEL
GUIDANCE INDICATES THE AFOREMENTIONED SHEAR AXIS SLOWLY PROGRESSING
EASTWARD TOWARD THE CENTRAL CAROLINAS...WITH THE MORE POTENT
SHORTWAVE ENERGY OVER THE SOUTHEAST STATES DEAMPLIFYING AS IT
PROGRESSES TOWARD THE SOUTHEAST COAST. WILL INDICATE 20-30% CHANCES
THROUGH MIDNIGHT (HIGHEST EAST)...WITH 20% IN THE COASTAL PLAIN
THROUGH SUNRISE THU...DRY ELSEWHERE. LOWS THU MORNING EXPECTED TO
RANGE FROM THE LOWER 60S (WEST) TO MID/UPPER 60S (EAST). -VINCENT
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
THE LATEST LONG RANGE MODEL GUIDANCE INDICATES A CHANGE IN THE
SYNOPTIC PATTERN OVER THE REGION THIS WEEKEND THROUGH EARLY NEXT
WEEK...WITH TROUGHING OVER THE EASTERN CONUS GIVING WAY TO A
STRENGTHENING UPPER LEVEL RIDGE OVER THE EAST COAST...AND
UNSEASONABLY STRONG SURFACE HIGH PRESSURE EXTENDING SOUTHWARD FROM
NEW ENGLAND INTO THE MID-ATLANTIC AND CAROLINAS. THE PRIMARY
UNCERTAINTY W/REGARD TO THE EXTENDED FORECAST APPEARS TO REVOLVE
AROUND THE EVOLUTION OF A POTENTIAL TROPICAL SYSTEM LATE IN THE
EXTENDED PERIOD (EARLY NEXT WEEK). AT THIS POINT...EXPECT NEAR
NORMAL TEMPERATURES AND PRECIP CHANCES ON THU-FRI...FOLLOWED BY NEAR
NORMAL TEMPERATURES AND BELOW NORMAL PRECIP CHANCES OVER THE
WEEKEND. AS MENTIONED ABOVE...UNCERTAINTY INCREASES CONSIDERABLY BY
EARLY NEXT WEEK...AND AT THIS TIME WILL INDICATE CLIMATOLOGICAL
CONDITIONS ON MONDAY. -VINCENT
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 800 PM MONDAY...
CONVECTION HAS NOT BEEN TOO MUCH OF A CONCERN THIS EVENING...
ALTHOUGH THERE ARE A FEW STORMS NEAR THE TRIAD (KINT AND KGSO) AND
HAVE THEREFORE INCLUDED MENTION OF SHOWERS/STORMS IN THEIR TAFS FOR
THE NEXT SEVERAL HOURS. THERE COULD ALSO BE SOME PRECIP ACROSS THE
EXTREME SOUTHEAST (MAYBE AFFECTING KFAY) LATER TONIGHT...BUT HAVE
LEFT ANY MENTION OUT OF THE TAFS FOR NOW DUE TO UNCERTAINTY. THE
BIGGEST AVIATION CONCERN FOR THE OVERNIGHT PERIOD WILL BE THE
POTENTIAL THE DEVELOPMENT OF FOG AND/OR STRATUS. THERE COULD BE SOME
DRIER MID LEVEL AIR MOVE IN WHICH WOULD RESULT IN MORE FOG...BUT IF
THAT DOES NOT OCCUR STRATUS WOULD BE MORE OF AN ISSUE.
NEVERTHELESS...MVFR/IFR CONDITIONS WILL BE POSSIBLE AT ALL TAF SITES
AFTER MIDNIGHT...ALTHOUGH CONFIDENCE IS LOWER THAN PREVIOUS NIGHT.
THEN...MORE SHOWERS AND STORMS ARE EXPECTED TO AFFECT CENTRAL NC
TUESDAY...MAINLY ACROSS THE SOUTHEASTERN PORTIONS OF THE FORECAST
AREA...BUT HAVE LEFT ANY MENTION OUT OF THE TAFS FOR NOW DUE TO THE
UNCERTAINTY OF COVERAGE AND EXACT LOCATION THIS FAR OUT.
OUTLOOK...THE UPPER LEVEL TROUGH THAT HAS BEEN RESPONSIBLE FOR THE
UNSETTLED WEATHER PATTERN RECENTLY IS EXPECTED TO GRADUALLY WEAKEN
AND LIFT NORTHWARD THROUGH THE END OF THE WEEK. THIS SUGGESTS A
GRADUAL IMPROVEMENT (I.E. FEWER SHOWERS AND T-STORMS) DURING THE
LATER HALF OF THE FORECAST PERIOD.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...BSD/ELLIS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
802 PM EDT MON AUG 20 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PARKED OVER THE MISSISSIPPI VALLEY WILL
CONTINUE TO BRING COOLER AND MORE UNSETTLED WEATHER TO THE AREA
THROUGH THE END OF THE WEAK BEFORE HIGHER PRESSURE MOVES IN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 240 PM MONDAY...
CURRENTLY THE UPPER LEVEL TROUGH IS PARKED OVER THE MISSISSIPPI
VALLEY WITH A PARENT UPPER LEVEL LOW OVER NORTHERN QUEBEC. AT THE
SURFACE CENTRAL NC IS CURRENTLY IN A VERY WEAK GRADIENT BETWEEN A
MESO-LOW EXITING TO THE NORTHEAST AND SURFACE HIGH TO THE NORTHWEST.
THIS HAS RESULTED IN VERY WEAK FLOW AT THE SURFACE. MOST STRATUS
LEFT FROM THIS MORNING HAS ERODED AND ALLOWED A BROKEN CUMULUS FIELD
TO DEVELOP ACROSS THE STATE. SOME VERY LIGHT SHOWERS ARE BEGINNING
TO POP UP ESPECIALLY IN NORTHEASTERN SECTIONS OF THE CWA. BACK TO
THE NORTHWEST...A STRONGER LINE OF CONVECTION HAS DEVELOPED OFF OF
THE VIRGINIA MOUNTAINS AND IS SLOWLY WORKING SOUTHEASTWARD. WHETHER
OR NOT DYNAMICS ARE GOOD ENOUGH TO SUSTAIN THIS ACTIVITY INTO THE
NORTHWEST PIEDMONT REMAINS TO BE SEEN. THE HRRR MODEL DOES RESOLVE
THIS FEATURE AND BRINGS BRIEF SHOWERS AND STORMS INTO THE TRIAD BY
22Z. ASIDE FROM THE FAR NORTHWEST...BULK SHEAR IS HIGH ACROSS THE
STATE (50-60 KNOTS) DUE TO AN EXITING UPPER LEVEL JET. ALMOST ALL OF
THIS SHEAR IS IN THE UPPER ELEVATIONS AS SHEAR IN THE LOWER LEVELS
IS ALMOST NOT EXISTENT. ALTHOUGH INSTABILITY IS SOMEWHAT LACKING
ACROSS THE CWA THERE SHOULD BE AT LEAST 500 J TO WORK WITH AND WITH
CONVECTIVE TEMPERATURES AT ONLY 76 DEGREES...SHOWERS HAVE NOT HAD
TROUBLE INITIATING BUT THE QUESTION REMAINS ON HOW FAR THEY CAN
DEVELOP. DEWPOINTS STRUGGLING TO STAY IN THE MID 60S IN THE
NORTHWEST WITH UPPER 60S SOUTHEAST. THIS AFTERNOON EXPECT SOME
SHOWERS AND STORMS TO DEVELOP...ESPECIALLY IN THE EAST. DO NOT
EXPECT MUCH IN THE WAY OF SEVERE ACTIVITY ALTHOUGH IF IT WERE TO
OCCUR THE MAIN THREAT WOULD BE DAMAGING WINDS. SKINNY CAPE PROFILES
DO NOT SUPPORT HAIL VERY WELL ALTHOUGH FREEZING LEVELS ARE LOWER
THAN IN PREVIOUS DAYS AT 13.5 KFT. MAXIMUM TEMPERATURES THIS
AFTERNOON WILL TOP OUT IN THE LOWER 80S.
TONIGHT HIGH RESOLUTION MODELS DO TRY TO CONTINUE OF WAVE OF
CONVECTION OFF THE MOUNTAINS BUT THIS SHOULD STRUGGLE TO SURVIVE
WITH LACK OF DAYTIME HEATING. THE BIGGER PROBLEM FOR THE OVERNIGHT
HOURS...ESPECIALLY IN THE EAST WILL BE AREAS OF FOG WHICH COULD
BEGIN JUST AFTER 9Z AND COULD REMAIN THROUGH SUNRISE. AN SPS OR
DENSE FOG ADVISORY WOULD NOT BE OUT OF THE QUESTION EAST OF I-95. IN
THE TRIAD THERE WILL BE LESS MOISTURE TO SUPPORT FOG DEVELOPMENT BUT
SOME VISIBILITY REDUCTIONS DURING THE OVERNIGHT HOURS ARE STILL
POSSIBLE. LOWS OVERNIGHT IN THE MID TO UPPER 60S.
FOR TUESDAY THE CHANCES FOR SEVERE WEATHER FOR TOMORROW AFTERNOON
WILL BE A BIT BETTER WITH MORE INSTABILITY AVAILABLE BUT IT WILL BE
CONFINED TO EASTERN PORTIONS OF THE CWA AND SHOULD STILL BE
ISOLATED. SHEAR WILL STILL BE PLENTIFUL AS THE JET CONTINUES TO MAKE
AN EXIT TO THE NORTHEAST. DURING THE AFTERNOON HOURS A 500 MB VORT
MAX SHOULD MAKE HEADWAY UP THE COAST BUT WHETHER OR NOT THIS FEATURE
PASSES CLOSE ENOUGH TO THE EASTERN PERIPHERY TO HELP SUPPORT
CONVECTION REMAINS TO BE SEEN. SURFACE HIGH PRESSURE TO THE
NORTHWEST WILL START TO WORK INTO THE AREA...POTENTIALLY CONFINING
CONVECTION EVEN FURTHER TO THE EAST DEPENDING ON PROGRESS. WHILE THE
UPPER LEVEL TROUGH WILL STILL BE IN PLACE IT WILL BEGIN TO LIFT OUT
AS THE UPPER JET CONTINUES UP THE EASTERN SEABOARD. MAX TEMPERATURES
TUESDAY WILL BE IN THE LOWER 80S WITH LOWS TUESDAY NIGHT IN THE MID
60S.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
THE LATEST 12Z MODEL GUIDANCE INDICATES SHORTWAVE ENERGY DIGGING
SOUTHEAST THROUGH THE CENTRAL PLAINS ON TUE...AND INTO THE LOWER MS
RIVER VALLEY/DEEP SOUTH ON WED...PROGRESSING EASTWARD INTO THE
SOUTHEAST STATES WED NIGHT...WITH A LOW-LEVEL TROUGH (OR WEAK
SFC-H85 LOW) DOWNSTREAM OVER THE EASTERN CAROLINAS. A SHEAR AXIS IS
EXPECTED TO EXTEND SW-NE ALONG THE APPALACHIANS IN BOTH WED/WED
NIGHT...PROGRESSING SLOWLY EASTWARD TOWARD THE CENTRAL CAROLINAS/VA.
UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF UPSTREAM SHORTWAVE
ENERGY...LENDING UNCERTAINTY TO THE LOW-LEVEL PATTERN OVER THE
CAROLINAS WED/WED NIGHT. AS A RESULT...A FAIR AMOUNT OF UNCERTAINTY
IS PRESENT WITH TEMPERATURES...CLOUD COVER AND PRECIPITATION
CHANCES...ESPECIALLY DURING THE DAY WED. HOWEVER...MODEL GUIDANCE IS
IN RELATIVELY GOOD AGREEMENT ON THE OVERALL PATTERN...WHICH WOULD
SUGGEST MORE CLOUD COVER...COOLER TEMPERATURES AND BETTER CHANCES
FOR SHOWER ACTIVITY IN EASTERN PORTIONS OF THE AREA. WILL INDICATE
PRECIP CHANCES RANGING FROM 20-40% ON WED (HIGHEST EAST)...WITH
HIGHS IN THE MID 80S WEST TO NEAR 80F EAST. FOR WED NIGHT...MODEL
GUIDANCE INDICATES THE AFOREMENTIONED SHEAR AXIS SLOWLY PROGRESSING
EASTWARD TOWARD THE CENTRAL CAROLINAS...WITH THE MORE POTENT
SHORTWAVE ENERGY OVER THE SOUTHEAST STATES DEAMPLIFYING AS IT
PROGRESSES TOWARD THE SOUTHEAST COAST. WILL INDICATE 20-30% CHANCES
THROUGH MIDNIGHT (HIGHEST EAST)...WITH 20% IN THE COASTAL PLAIN
THROUGH SUNRISE THU...DRY ELSEWHERE. LOWS THU MORNING EXPECTED TO
RANGE FROM THE LOWER 60S (WEST) TO MID/UPPER 60S (EAST). -VINCENT
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
THE LATEST LONG RANGE MODEL GUIDANCE INDICATES A CHANGE IN THE
SYNOPTIC PATTERN OVER THE REGION THIS WEEKEND THROUGH EARLY NEXT
WEEK...WITH TROUGHING OVER THE EASTERN CONUS GIVING WAY TO A
STRENGTHENING UPPER LEVEL RIDGE OVER THE EAST COAST...AND
UNSEASONABLY STRONG SURFACE HIGH PRESSURE EXTENDING SOUTHWARD FROM
NEW ENGLAND INTO THE MID-ATLANTIC AND CAROLINAS. THE PRIMARY
UNCERTAINTY W/REGARD TO THE EXTENDED FORECAST APPEARS TO REVOLVE
AROUND THE EVOLUTION OF A POTENTIAL TROPICAL SYSTEM LATE IN THE
EXTENDED PERIOD (EARLY NEXT WEEK). AT THIS POINT...EXPECT NEAR
NORMAL TEMPERATURES AND PRECIP CHANCES ON THU-FRI...FOLLOWED BY NEAR
NORMAL TEMPERATURES AND BELOW NORMAL PRECIP CHANCES OVER THE
WEEKEND. AS MENTIONED ABOVE...UNCERTAINTY INCREASES CONSIDERABLY BY
EARLY NEXT WEEK...AND AT THIS TIME WILL INDICATE CLIMATOLOGICAL
CONDITIONS ON MONDAY. -VINCENT
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 800 PM MONDAY...
CONVECTION HAS NOT BEEN TOO MUCH OF A CONCERN THIS EVENING...
ALTHOUGH THERE ARE A FEW STORMS NEAR THE TRIAD (KINT AND KGSO) AND
HAVE THEREFORE INCLUDED MENTION OF SHOWERS/STORMS IN THEIR TAFS FOR
THE NEXT SEVERAL HOURS. THERE COULD ALSO BE SOME PRECIP ACROSS THE
EXTREME SOUTHEAST (MAYBE AFFECTING KFAY) LATER TONIGHT...BUT HAVE
LEFT ANY MENTION OUT OF THE TAFS FOR NOW DUE TO UNCERTAINTY. THE
BIGGEST AVIATION CONCERN FOR THE OVERNIGHT PERIOD WILL BE THE
POTENTIAL THE DEVELOPMENT OF FOG AND/OR STRATUS. THERE COULD BE SOME
DRIER MID LEVEL AIR MOVE IN WHICH WOULD RESULT IN MORE FOG...BUT IF
THAT DOES NOT OCCUR STRATUS WOULD BE MORE OF AN ISSUE.
NEVERTHELESS...MVFR/IFR CONDITIONS WILL BE POSSIBLE AT ALL TAF SITES
AFTER MIDNIGHT...ALTHOUGH CONFIDENCE IS LOWER THAN PREVIOUS NIGHT.
THEN...MORE SHOWERS AND STORMS ARE EXPECTED TO AFFECT CENTRAL NC
TUESDAY...MAINLY ACROSS THE SOUTHEASTERN PORTIONS OF THE FORECAST
AREA...BUT HAVE LEFT ANY MENTION OUT OF THE TAFS FOR NOW DUE TO THE
UNCERTAINTY OF COVERAGE AND EXACT LOCATION THIS FAR OUT.
OUTLOOK...THE UPPER LEVEL TROUGH THAT HAS BEEN RESPONSIBLE FOR THE
UNSETTLED WEATHER PATTERN RECENTLY IS EXPECTED TO GRADUALLY WEAKEN
AND LIFT NORTHWARD THROUGH THE END OF THE WEEK. THIS SUGGESTS A
GRADUAL IMPROVEMENT (I.E. FEWER SHOWERS AND T-STORMS) DURING THE
LATER HALF OF THE FORECAST PERIOD.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
929 PM EDT MON AUG 20 2012
.SYNOPSIS...
A COUPLE OF UPPER LEVEL DISTURBANCES WILL MOVE THROUGH THE
FORECAST AREA THROUGH TUESDAY EVENING KEEPING PRECIPITATION
CHANCES IN THE FORECAST ACROSS THE REGION. HIGH PRESSURE WILL THEN
MOVE INTO THE AREA FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A MID LEVEL SHORT WAVE IS PROGRESSING SLOWLY EAST ACROSS THE
REGION THIS EVENING. THIS IS HELPING TO MAINTAIN SOME SHOWER AND
THUNDERSTORM ACTIVITY ACROSS PARTS OF INDIANA AND INTO NORTHWEST
OHIO. THIS ACTIVITY HAS SHOWN A GRADUAL WEAKENING TREND AND WOULD
EXPECT THAT TO CONTINUE AS IT PUSHES EAST INTO OUR WESTERN AREA
THROUGH LATE EVENING. WE PRETTY MUCH LOSE ALL INSTABILITY BY 06Z
SO WILL JUST HANG ON TO A SLIGHT CHANCE OF SHOWERS ACROSS
PRIMARILY THE WEST THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. AT
THE MOMENT...SKIES HAVE GENERALLY CLEARED OFF ACROSS OUR FA BUT DO
EXPECT TO SEE AT LEAST A PARTIAL INCREASE IN CLOUDS THROUGH THE
OVERNIGHT HOURS AS SHORT WAVE MOVES IN. WILL STICK WITH LOWS IN
THE MID 50S...BUT THIS COULD BE ON THE COOL SIDE IF WE END UP WITH
ENOUGH CLOUDS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOTHER UPPER LEVEL DISTURBANCE WILL WORK THROUGH THE FA ON
TUESDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
DURING THE DAY AS THIS FEATURE MOVES THROUGH THE REGION. A FEW OF
THE STORMS MAY PRODUCE SOME HAIL ON TUESDAY. WITH ADDITIONAL
CLOUD COVER AND PRECIPITATION ACROSS THE FA ON TUESDAY HIGH
TEMPERATURES WILL BE LIMITED TO THE MIDDLE 70S TO AROUND 80.
PRECIPITATION WILL TAPER OFF BY THE EVENING HOURS ON TUESDAY AND
HIGH PRESSURE WILL WORK INTO THE FA FOR THE REMAINDER OF THE SHORT
TERM TIME FRAME. TEMPERATURES WILL BE SLIGHTLY WARMER ON WEDNESDAY
WITH MORE SUNSHINE ACROSS THE AREA. HIGHS ON WEDNESDAY WILL REACH
UP INTO THE LOWER 80S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
SLOWLY BUILDING UPPER HEIGHTS ALONG WITH SOUTHERLY FLOW ON THE BACK
SIDE OF A SURFACE HIGH WILL RESULT IN ABOVE NORMAL TEMPERATURES AND
DRY CONDITIONS THROUGH THE PERIOD. THERE IS SOME POSSIBILITY THAT A
WEAK BOUNDARY COULD APPROACH THE NORTHWEST COUNTIES EARLY NEXT WEEK.
BUT CHANCE OF RAIN REMAINS QUITE LOW AT THIS POINT.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
SHORT WAVE ENERGY PUSHING ACROSS INDIANA IS HELPING TO MAINTAIN
A FEW SHOWERS AND THUNDERSTORMS INTO THIS EVENING. AS WE CONTINUE
TO LOSE INSTABILITY THROUGH THIS EVENING...WOULD EXPECT TO SEE AN
OVERALL WEAKENING TREND. HOWEVER...BOTH THE 18Z NAM AND LATEST FEW
RUNS OF THE HRRR ARE SHOWING SOME SHOWER ACTIVITY WORKING IN FROM
THE WEST LATER TONIGHT. WILL HOLD OFF ON ANY PCPN IN THE TAFS FOR
THIS BUT WILL BRING SOME LOWER VFR CIGS IN AS THE SHORT WAVE MOVES
THROUGH. THIS SHOULD HELP LIMIT BR DEVELOPMENT...BUT IF WE END UP
WITH MORE BREAKS THAN NOT...SOME MVFR BR WILL BE POSSIBLE...ESPECIALLY
AT THE MORE FAVORABLE KLUK AND POSSIBLY KILN. AS THE LOW LEVEL
TROUGH AXIS WORKS EAST THROUGH THE DAY ON TUESDAY...EXPECT
ISOLATED TO SCATTERED SHOWER DEVELOPMENT AS WE DESTABILIZE THROUGH
THE AFTERNOON HOURS. SOME TIMING DIFFERENCES EXIST AMONG THE
MODELS THOUGH...SO EXACT LOCATION OF ANY INITIATION REMAINS
SOMEWHAT UNCERTAIN.
.OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...JGL
SHORT TERM...NOVAK
LONG TERM...
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
749 PM EDT MON AUG 20 2012
.SYNOPSIS...
A COUPLE OF UPPER LEVEL DISTURBANCES WILL MOVE THROUGH THE
FORECAST AREA THROUGH TUESDAY EVENING KEEPING PRECIPITATION
CHANCES IN THE FORECAST ACROSS THE REGION. HIGH PRESSURE WILL THEN
MOVE INTO THE AREA FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A WEAK UPPER LEVEL DISTURBANCE WILL ALLOW FOR SOME SHOWERS AND
THUNDERSTORMS ACROSS THE AREA THIS EVENING. PRECIPITATION CHANCES
WILL TAPER OFF LATER THIS EVENING ALTHOUGH AN ISOLATED SHOWER WILL
BE POSSIBLE FOR THE OVERNIGHT TIME FRAME ACROSS EASTERN INDIANA
AND WESTERN OHIO. WENT CLOSE TO GUIDANCE FOR OVERNIGHT LOW TEMPERATURES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
ANOTHER UPPER LEVEL DISTURBANCE WILL WORK THROUGH THE FA ON
TUESDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
DURING THE DAY AS THIS FEATURE MOVES THROUGH THE REGION. A FEW OF
THE STORMS MAY PRODUCE SOME HAIL ON TUESDAY. WITH ADDITIONAL
CLOUD COVER AND PRECIPITATION ACROSS THE FA ON TUESDAY HIGH
TEMPERATURES WILL BE LIMITED TO THE MIDDLE 70S TO AROUND 80.
PRECIPITATION WILL TAPER OFF BY THE EVENING HOURS ON TUESDAY AND
HIGH PRESSURE WILL WORK INTO THE FA FOR THE REMAINDER OF THE SHORT
TERM TIME FRAME. TEMPERATURES WILL BE SLIGHTLY WARMER ON WEDNESDAY
WITH MORE SUNSHINE ACROSS THE AREA. HIGHS ON WEDNESDAY WILL REACH
UP INTO THE LOWER 80S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
SLOWLY BUILDING UPPER HEIGHTS ALONG WITH SOUTHERLY FLOW ON THE BACK
SIDE OF A SURFACE HIGH WILL RESULT IN ABOVE NORMAL TEMPERATURES AND
DRY CONDITIONS THROUGH THE PERIOD. THERE IS SOME POSSIBILITY THAT A
WEAK BOUNDARY COULD APPROACH THE NORTHWEST COUNTIES EARLY NEXT WEEK.
BUT CHANCE OF RAIN REMAINS QUITE LOW AT THIS POINT.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SHORT WAVE ENERGY PUSHING ACROSS INDIANA IS HELPING TO MAINTAIN
A FEW SHOWERS AND THUNDERSTORMS INTO THIS EVENING. AS WE CONTINUE
TO LOSE INSTABILITY THROUGH THIS EVENING...WOULD EXPECT TO SEE AN
OVERALL WEAKENING TREND. HOWEVER...BOTH THE 18Z NAM AND LATEST FEW
RUNS OF THE HRRR ARE SHOWING SOME SHOWER ACTIVITY WORKING IN FROM
THE WEST LATER TONIGHT. WILL HOLD OFF ON ANY PCPN IN THE TAFS FOR
THIS BUT WILL BRING SOME LOWER VFR CIGS IN AS THE SHORT WAVE MOVES
THROUGH. THIS SHOULD HELP LIMIT BR DEVELOPMENT...BUT IF WE END UP
WITH MORE BREAKS THAN NOT...SOME MVFR BR WILL BE POSSIBLE...ESPECIALLY
AT THE MORE FAVORABLE KLUK AND POSSIBLY KILN. AS THE LOW LEVEL
TROUGH AXIS WORKS EAST THROUGH THE DAY ON TUESDAY...EXPECT
ISOLATED TO SCATTERED SHOWER DEVELOPMENT AS WE DESTABILIZE THROUGH
THE AFTERNOON HOURS. SOME TIMING DIFFERENCES EXIST AMONG THE
MODELS THOUGH...SO EXACT LOCATION OF ANY INITIATION REMAINS
SOMEWHAT UNCERTAIN.
.OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...NOVAK
SHORT TERM...NOVAK
LONG TERM...
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1013 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING TODAY INTO TUESDAY. THE DEEPER
MOISTURE FOR THESE FEATURES TO TAP...MAINLY FROM MOUNTAINS ON EAST.
WEAK HIGH PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1000AM UPDATE...
AREA OF RAIN WITH DISTURBANCE ABOUT READY TO BE EXODUS FROM
POCAHONTAS AND EASTERN RANDOLPH...WITHIN THE NEXT HR OR SO.
IN ITS WAKE THE LOW CLDS HAVE MANAGED TO MIX OUT THIS MORNING WITH
SOME HEATING...ALLOWING FOR QUITE A BIT OF SUN ACROSS SE OH INTO
WESTERN WV. THIS WILL TEND TO FILL BACK IN...ACROSS WESTERN WV...NEXT
FEW HRS...AS MORE CLDS STREAM NE FROM EASTERN KY. NEAR TERM MDLS
SHOW SOME AFTN SHRA/TSRA DEVELOPMENT ACROSS THE MTNS BACK TO
CENTRAL PORTIONS OF WV...AIDED BY SOME HEATING AND LINGERING MOISTURE. THUS
WILL PUT SOME CHC POPS IN THIS AFTN CENTRAL/NORTHERN WV LOWLANDS
INTO NORTHERN MTNS. ALSO HAVE SOME CHC POPS ACROSS PORTIONS OF SE
OH LATE CLOSER TO UPR TROF.
PREVIOUS DISCUSSION BELOW...
BROAD MID/UPPER LEVEL TROF HERE FOR SEVERAL DAYS.
BASING FORECAST ON A STRONGER LEADING 500 MB VORT MAX PASSING FROM
SOUTHWEST TO NORTHEAST 12Z TO 16Z...EXITING THE NRN WV MOUNTAINS
AROUND 17Z. SO WILL BE FASTER IN INCREASING CLOUDS AND POPS EARLY
THIS MORNING OVER THE MOUNTAINOUS COUNTIES...PEAKING IN POCAHONTAS
COUNTY AROUND 14/15Z. DID NOT MENTION THUNDER. AS A RESULT OF THE
THICKENING AND LOWERING CLOUDS...REDUCE ANY THICK VALLEY FOG.
ONCE THAT FEATURE EXITS...HARD TO DETERMINE IF ANY SHOWERS DEVELOP
FURTHER WEST...ACROSS THE LOWLANDS DURING THE AFTERNOON AND
EVENING. SOME OF THE NEAR TERM MODELS...LIKE THE HRRR AND WRF-NMM
ARE DEVELOPING SHOWERS...MAYBE RELATED THE THE LOW LEVEL DEW POINT
GRADIENT BEING SHOVED BACK NORTHWEST TODAY. WILL TRY TO KEEP MOST
POPS IN WAKE OF THIS MORNINGS FEATURE...IN THE 20 OR LESS
CATEGORY...THINKING THE MAXIMUM IN MOISTURE IN THE OHIO VALLEY WILL
MOVE INTO NORTHERN HALF OF OHIO BY LATE THIS AFTERNOON...NOT THE
SOUTHERN COUNTIES.
00Z NAM WAS FASTER THAN THE 00Z GFS IN REDUCING MEAN RELATIVE
HUMIDITY IN THE COLUMN TONIGHT. FOR NOW...DO NOT SEE ANY REASON TO
ADJUST OUR 20/SLIGHT CHANCE POPS.
ALSO...DEPENDING ON THE RAIN TODAY...VALLEY FOG MAY HAVE TO BE
INSERTED FOR 06Z TO 12Z MONDAY...BUT A BIT PREMATURE AT THIS TIME.
COULD NOT HOLD MAXIMUM TEMPERATURES DOWN TOO MUCH TODAY...SINCE
HAVING THE MAIN SUPPORT EXITING BEFORE 18Z.
&&
.SHORT TERM /MONDAY/...
MODELS CONTINUE TO INDICATE 500MB TROUGH APPROACHING REGION HEADED
INTO SHORT TERM...WITH SEVERAL IMPULSES LIFTING THROUGH DURING THE
FIRST HALF OF THE WEEK. THE BEST MOISTURE IS GENERALLY IN THE WV
MOUNTAINS AND TO THE SOUTH EAST AND IT LOOKS LIKE THE MAIN SURFACE
LOW SHOULD ALSO STAY SOUTH EAST...SO KEPT HIGHEST POPS IN THE
MOUNTAINS DURING THE AFTERNOONS. MONDAY LOOKS LIKE THE DAY FOR THE
MOST COVERAGE OF PRECIP...AND HAVE CHANCE POPS FROM MOUNTAINS BACK
TO ABOUT THE OHIO RIVER...WITH SLIGHT CHANCE POPS INTO SE OHIO. POPS
LINGER INTO MONDAY NIGHT AS MODELS SHOW MOISTURE REMAINING WITH A
LITTLE RIPPLE ALOFT. SOME DIFFERENCES IN PLACEMENT BETWEEN
MODELS...BUT IN GENERAL SHOWING ANOTHER WEAK SHORTWAVE MOVING
THROUGH FOR TUESDAY AFTERNOON. BEST MOISTURE IS PROGGED TO BE
FARTHER EAST THAN ON MONDAY...SO KEPT CHANCE POPS MORE CLOSELY TIED
TO MOUNTAINS. MODELS SHOW RISING HEIGHTS HEADED INTO TUESDAY...AND
PUSH BEST MOISTURE EVEN FATHER EAST...SO LOOKS LIKE A DRIER DAY WITH
MAYBE JUST AN ISOLATED SHOWER IN MOUNTAINS.
ONLY MINIMAL CHANGES TO TEMPS THIS PACKAGE...STILL LOOKS LIKE A
GRADUAL WARMING TREND INTO MIDWEEK WITH NEAR NORMAL TEMPERATURES BY
WEDNESDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
USED A BLEND OF THE GFS AND ECMWF FOR WEDNESDAY THROUGH FRIDAY. THIS
LEAVES A WEAK HIGH PRESSURE SYSTEM OVER THE REGION...BUT POSSIBLY
ENOUGH MOISTURE TO FIRE SOME AFTERNOON SHOWERS/THUNDERSTORMS IN THE
MOUNTAINS. BY SATURDAY...SWITCHED TO A BLEND OF THE ECMWF AND GEFS
MEAN.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
WAS JUST A BIT FASTER WITH THE INCREASING MOISTURE MOVING UP THE
EASTERN SLOPES FOR THIS MORNING. AS A RESULT...NO THICK FOG SHOULD
BE SEEN AT DAWN.
THE 500 MB VORT MAX PASSES AROUND 15Z TO 16Z. BKW TO EKN CORRIDOR
SHOULD BE ALONG THE WESTERN EDGE OF THE MAIN SHOWER SHIELD
ASSOCIATED WITH THIS WAVE. THUNDER POSSIBLE NEAR THE VIRGINIA
BORDER. HAVE POPS PEAKING BY 14Z/15Z AROUND POCAHONTAS
COUNTY...BEFORE LOWERING AGAIN DURING THE 16Z TO 21Z PERIOD. HAVE
CEILINGS LOWERING AROUND 12Z ALONG THE EASTERN SLOPES INTO THE 2 TO
3 THSD FT BKN RANGE AND VSBY AROUND 5 MILES IN ANY RAIN SHOWERS.
FURTHER WEST HAVE MID DECK AROUND 10 THSD FT BEFORE SOME 4 TO 6 THSD
FT CEILINGS DEVELOPING BETWEEN 12Z TO 18Z.
ONCE THAT SUPPORT EXITS...DO NOT HAVE A GOOD HANDLE ON THE AMOUNT
AND HEIGHTS OF THE CLOUDS FOR LATE THIS AFTERNOON INTO THIS
EVENING...SAY 18Z TO 06Z. WILL LEAVE A SLIGHT CHANCE OF SHOWERS IN
FOR MANY AREAS...WITH WEAKER DISTURBANCES ALOFT...COMPARED TO THE
ONE THIS MORNING. VISIBILITY IN THE MOUNTAIN VALLEYS WILL LIKELY
DEPEND ON ANY RAIN TODAY...SO WILL HAVE TO BE FINE TUNED LATER
TODAY. THE MEDIUM CONFIDENCE MAINLY HAS TO DO WITH THESE
UNCERTAINTIES FOR LATE TODAY AND OVERNIGHT TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: FOG MAY BE MORE WIDESPREAD 06Z TO 12Z MONDAY IF
THE RAIN TODAY AFFECTS A WIDER AREA.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z MONDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/30
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
816 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING TODAY INTO TUESDAY. THE DEEPER
MOISTURE FOR THESE FEATURES TO TAP...MAINLY FROM MOUNTAINS ON EAST.
WEAK HIGH PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
800AM UPDATE...
SENT OUT AN UPDATE RAISING SKY GRIDS SIGNIFICANTLY THIS MORNING ACROSS
THE BOARD...WITH AN ABUNDANCE OF MID AND HI CLDS OVER THE AREA.
ALSO RAISED POPS WELL INTO CATEGORICAL ACROSS EASTERN SLOPES IN S
MTNS AND UP INTO POCAHONTAS...INSERTING RA INSTEAD OF SHRA WITH
SOME SCHC THUNDER AS WELL. MDLS ARE HAVING MAJOR STRUGGLES WITH
THE SPEED OF THIS SYS. BACK EDGE OF CLDS MOVING ENE ACROSS CENTRAL
KY ATTM AS DRY SLOT MARCHES STEADILY E. MUCH OF THE DEEPER MOISTURE
APPEARS TO BE ACROSS CENTRAL WV AND SHIFTING E. HAVE TIMED BACK EDGE
OF CLDS TO ENTER WESTERN FLANK 15-16Z WITH IMPROVING SKY
CONDITIONS...IF NOT SOONER AS SOME OF THE LINGERING MOISTURE ARND
H85 MAY TRY TO SCT OUT SOME. MAY SEE SOME SHRA/TSRA LIGHT UP ACROSS
CENTRAL WV THIS AFTN NEAR LLVL MOISTURE GRADIENT. NO OTHER CHANGES
ATTM.
PREVIOUS DISCUSSION BELOW...
BROAD MID/UPPER LEVEL TROF HERE FOR SEVERAL DAYS.
BASING FORECAST ON A STRONGER LEADING 500 MB VORT MAX PASSING FROM
SOUTHWEST TO NORTHEAST 12Z TO 16Z...EXITING THE NRN WV MOUNTAINS
AROUND 17Z. SO WILL BE FASTER IN INCREASING CLOUDS AND POPS EARLY
THIS MORNING OVER THE MOUNTAINOUS COUNTIES...PEAKING IN POCAHONTAS
COUNTY AROUND 14/15Z. DID NOT MENTION THUNDER. AS A RESULT OF THE
THICKENING AND LOWERING CLOUDS...REDUCE ANY THICK VALLEY FOG.
ONCE THAT FEATURE EXITS...HARD TO DETERMINE IF ANY SHOWERS DEVELOP
FURTHER WEST...ACROSS THE LOWLANDS DURING THE AFTERNOON AND
EVENING. SOME OF THE NEAR TERM MODELS...LIKE THE HRRR AND WRF-NMM
ARE DEVELOPING SHOWERS...MAYBE RELATED THE THE LOW LEVEL DEW POINT
GRADIENT BEING SHOVED BACK NORTHWEST TODAY. WILL TRY TO KEEP MOST
POPS IN WAKE OF THIS MORNINGS FEATURE...IN THE 20 OR LESS
CATEGORY...THINKING THE MAXIMUM IN MOISTURE IN THE OHIO VALLEY WILL
MOVE INTO NORTHERN HALF OF OHIO BY LATE THIS AFTERNOON...NOT THE
SOUTHERN COUNTIES.
00Z NAM WAS FASTER THAN THE 00Z GFS IN REDUCING MEAN RELATIVE
HUMIDITY IN THE COLUMN TONIGHT. FOR NOW...DO NOT SEE ANY REASON TO
ADJUST OUR 20/SLIGHT CHANCE POPS.
ALSO...DEPENDING ON THE RAIN TODAY...VALLEY FOG MAY HAVE TO BE
INSERTED FOR 06Z TO 12Z MONDAY...BUT A BIT PREMATURE AT THIS TIME.
COULD NOT HOLD MAXIMUM TEMPERATURES DOWN TOO MUCH TODAY...SINCE
HAVING THE MAIN SUPPORT EXITING BEFORE 18Z.
&&
.SHORT TERM /MONDAY/...
MODELS CONTINUE TO INDICATE 500MB TROUGH APPROACHING REGION HEADED
INTO SHORT TERM...WITH SEVERAL IMPULSES LIFTING THROUGH DURING THE
FIRST HALF OF THE WEEK. THE BEST MOISTURE IS GENERALLY IN THE WV
MOUNTAINS AND TO THE SOUTH EAST AND IT LOOKS LIKE THE MAIN SURFACE
LOW SHOULD ALSO STAY SOUTH EAST...SO KEPT HIGHEST POPS IN THE
MOUNTAINS DURING THE AFTERNOONS. MONDAY LOOKS LIKE THE DAY FOR THE
MOST COVERAGE OF PRECIP...AND HAVE CHANCE POPS FROM MOUNTAINS BACK
TO ABOUT THE OHIO RIVER...WITH SLIGHT CHANCE POPS INTO SE OHIO. POPS
LINGER INTO MONDAY NIGHT AS MODELS SHOW MOISTURE REMAINING WITH A
LITTLE RIPPLE ALOFT. SOME DIFFERENCES IN PLACEMENT BETWEEN
MODELS...BUT IN GENERAL SHOWING ANOTHER WEAK SHORTWAVE MOVING
THROUGH FOR TUESDAY AFTERNOON. BEST MOISTURE IS PROGGED TO BE
FARTHER EAST THAN ON MONDAY...SO KEPT CHANCE POPS MORE CLOSELY TIED
TO MOUNTAINS. MODELS SHOW RISING HEIGHTS HEADED INTO TUESDAY...AND
PUSH BEST MOISTURE EVEN FATHER EAST...SO LOOKS LIKE A DRIER DAY WITH
MAYBE JUST AN ISOLATED SHOWER IN MOUNTAINS.
ONLY MINIMAL CHANGES TO TEMPS THIS PACKAGE...STILL LOOKS LIKE A
GRADUAL WARMING TREND INTO MIDWEEK WITH NEAR NORMAL TEMPERATURES BY
WEDNESDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
USED A BLEND OF THE GFS AND ECMWF FOR WEDNESDAY THROUGH FRIDAY. THIS
LEAVES A WEAK HIGH PRESSURE SYSTEM OVER THE REGION...BUT POSSIBLY
ENOUGH MOISTURE TO FIRE SOME AFTERNOON SHOWERS/THUNDERSTORMS IN THE
MOUNTAINS. BY SATURDAY...SWITCHED TO A BLEND OF THE ECMWF AND GEFS
MEAN.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
WAS JUST A BIT FASTER WITH THE INCREASING MOISTURE MOVING UP THE
EASTERN SLOPES FOR THIS MORNING. AS A RESULT...NO THICK FOG SHOULD
BE SEEN AT DAWN.
THE 500 MB VORT MAX PASSES AROUND 15Z TO 16Z. BKW TO EKN CORRIDOR
SHOULD BE ALONG THE WESTERN EDGE OF THE MAIN SHOWER SHIELD
ASSOCIATED WITH THIS WAVE. THUNDER POSSIBLE NEAR THE VIRGINIA
BORDER. HAVE POPS PEAKING BY 14Z/15Z AROUND POCAHONTAS
COUNTY...BEFORE LOWERING AGAIN DURING THE 16Z TO 21Z PERIOD. HAVE
CEILINGS LOWERING AROUND 12Z ALONG THE EASTERN SLOPES INTO THE 2 TO
3 THSD FT BKN RANGE AND VSBY AROUND 5 MILES IN ANY RAIN SHOWERS.
FURTHER WEST HAVE MID DECK AROUND 10 THSD FT BEFORE SOME 4 TO 6 THSD
FT CEILINGS DEVELOPING BETWEEN 12Z TO 18Z.
ONCE THAT SUPPORT EXITS...DO NOT HAVE A GOOD HANDLE ON THE AMOUNT
AND HEIGHTS OF THE CLOUDS FOR LATE THIS AFTERNOON INTO THIS
EVENING...SAY 18Z TO 06Z. WILL LEAVE A SLIGHT CHANCE OF SHOWERS IN
FOR MANY AREAS...WITH WEAKER DISTURBANCES ALOFT...COMPARED TO THE
ONE THIS MORNING. VISIBILITY IN THE MOUNTAIN VALLEYS WILL LIKELY
DEPEND ON ANY RAIN TODAY...SO WILL HAVE TO BE FINE TUNED LATER
TODAY. THE MEDIUM CONFIDENCE MAINLY HAS TO DO WITH THESE
UNCERTAINTIES FOR LATE TODAY AND OVERNIGHT TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: FOG MAY BE MORE WIDESPREAD 06Z TO 12Z MONDAY IF
THE RAIN TODAY AFFECTS A WIDER AREA.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M H H H H H H H H H H H
AFTER 12Z MONDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/30
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
607 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING TODAY INTO TUESDAY. THE DEEPER
MOISTURE FOR THESE FEATURES TO TAP...MAINLY FROM MOUNTAINS ON EAST.
WEAK HIGH PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD MID/UPPER LEVEL TROF HERE FOR SEVERAL DAYS.
BASING FORECAST ON A STRONGER LEADING 500 MB VORT MAX PASSING FROM
SOUTHWEST TO NORTHEAST 12Z TO 16Z...EXITING THE NRN WV MOUNTAINS
AROUND 17Z. SO WILL BE FASTER IN INCREASING CLOUDS AND POPS EARLY
THIS MORNING OVER THE MOUNTAINOUS COUNTIES...PEAKING IN POCAHONTAS
COUNTY AROUND 14/15Z. DID NOT MENTION THUNDER. AS A RESULT OF THE
THICKENING AND LOWERING CLOUDS...REDUCE ANY THICK VALLEY FOG.
ONCE THAT FEATURE EXITS...HARD TO DETERMINE IF ANY SHOWERS DEVELOP
FURTHER WEST...ACROSS THE LOWLANDS DURING THE AFTERNOON AND
EVENING. SOME OF THE NEAR TERM MODELS...LIKE THE HRRR AND WRF-NMM
ARE DEVELOPING SHOWERS...MAYBE RELATED THE THE LOW LEVEL DEW POINT
GRADIENT BEING SHOVED BACK NORTHWEST TODAY. WILL TRY TO KEEP MOST
POPS IN WAKE OF THIS MORNINGS FEATURE...IN THE 20 OR LESS
CATEGORY...THINKING THE MAXIMUM IN MOISTURE IN THE OHIO VALLEY WILL
MOVE INTO NORTHERN HALF OF OHIO BY LATE THIS AFTERNOON...NOT THE
SOUTHERN COUNTIES.
00Z NAM WAS FASTER THAN THE 00Z GFS IN REDUCING MEAN RELATIVE
HUMIDITY IN THE COLUMN TONIGHT. FOR NOW...DO NOT SEE ANY REASON TO
ADJUST OUR 20/SLIGHT CHANCE POPS.
ALSO...DEPENDING ON THE RAIN TODAY...VALLEY FOG MAY HAVE TO BE
INSERTED FOR 06Z TO 12Z MONDAY...BUT A BIT PREMATURE AT THIS TIME.
COULD NOT HOLD MAXIMUM TEMPERATURES DOWN TOO MUCH TODAY...SINCE
HAVING THE MAIN SUPPORT EXITING BEFORE 18Z.
&&
.SHORT TERM /MONDAY/...
MODELS CONTINUE TO INDICATE 500MB TROUGH APPROACHING REGION HEADED
INTO SHORT TERM...WITH SEVERAL IMPULSES LIFTING THROUGH DURING THE
FIRST HALF OF THE WEEK. THE BEST MOISTURE IS GENERALLY IN THE WV
MOUNTAINS AND TO THE SOUTH EAST AND IT LOOKS LIKE THE MAIN SURFACE
LOW SHOULD ALSO STAY SOUTH EAST...SO KEPT HIGHEST POPS IN THE
MOUNTAINS DURING THE AFTERNOONS. MONDAY LOOKS LIKE THE DAY FOR THE
MOST COVERAGE OF PRECIP...AND HAVE CHANCE POPS FROM MOUNTAINS BACK
TO ABOUT THE OHIO RIVER...WITH SLIGHT CHANCE POPS INTO SE OHIO. POPS
LINGER INTO MONDAY NIGHT AS MODELS SHOW MOISTURE REMAINING WITH A
LITTLE RIPPLE ALOFT. SOME DIFFERENCES IN PLACEMENT BETWEEN
MODELS...BUT IN GENERAL SHOWING ANOTHER WEAK SHORTWAVE MOVING
THROUGH FOR TUESDAY AFTERNOON. BEST MOISTURE IS PROGGED TO BE
FARTHER EAST THAN ON MONDAY...SO KEPT CHANCE POPS MORE CLOSELY TIED
TO MOUNTAINS. MODELS SHOW RISING HEIGHTS HEADED INTO TUESDAY...AND
PUSH BEST MOISTURE EVEN FATHER EAST...SO LOOKS LIKE A DRIER DAY WITH
MAYBE JUST AN ISOLATED SHOWER IN MOUNTAINS.
ONLY MINIMAL CHANGES TO TEMPS THIS PACKAGE...STILL LOOKS LIKE A
GRADUAL WARMING TREND INTO MIDWEEK WITH NEAR NORMAL TEMPERATURES BY
WEDNESDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
USED A BLEND OF THE GFS AND ECMWF FOR WEDNESDAY THROUGH FRIDAY. THIS
LEAVES A WEAK HIGH PRESSURE SYSTEM OVER THE REGION...BUT POSSIBLY
ENOUGH MOISTURE TO FIRE SOME AFTERNOON SHOWERS/THUNDERSTORMS IN THE
MOUNTAINS. BY SATURDAY...SWITCHED TO A BLEND OF THE ECMWF AND GEFS
MEAN.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
WAS JUST A BIT FASTER WITH THE INCREASING MOISTURE MOVING UP THE
EASTERN SLOPES FOR THIS MORNING. AS A RESULT...NO THICK FOG SHOULD
BE SEEN AT DAWN.
THE 500 MB VORT MAX PASSES AROUND 15Z TO 16Z. BKW TO EKN CORRIDOR
SHOULD BE ALONG THE WESTERN EDGE OF THE MAIN SHOWER SHIELD
ASSOCIATED WITH THIS WAVE. THUNDER POSSIBLE NEAR THE VIRGINIA
BORDER. HAVE POPS PEAKING BY 14Z/15Z AROUND POCAHONTAS
COUNTY...BEFORE LOWERING AGAIN DURING THE 16Z TO 21Z PERIOD. HAVE
CEILINGS LOWERING AROUND 12Z ALONG THE EASTERN SLOPES INTO THE 2 TO
3 THSD FT BKN RANGE AND VSBY AROUND 5 MILES IN ANY RAIN SHOWERS.
FURTHER WEST HAVE MID DECK AROUND 10 THSD FT BEFORE SOME 4 TO 6 THSD
FT CEILINGS DEVELOPING BETWEEN 12Z TO 18Z.
ONCE THAT SUPPORT EXITS...DO NOT HAVE A GOOD HANDLE ON THE AMOUNT
AND HEIGHTS OF THE CLOUDS FOR LATE THIS AFTERNOON INTO THIS
EVENING...SAY 18Z TO 06Z. WILL LEAVE A SLIGHT CHANCE OF SHOWERS IN
FOR MANY AREAS...WITH WEAKER DISTURBANCES ALOFT...COMPARED TO THE
ONE THIS MORNING. VISIBILITY IN THE MOUNTAIN VALLEYS WILL LIKELY
DEPEND ON ANY RAIN TODAY...SO WILL HAVE TO BE FINE TUNED LATER
TODAY. THE MEDIUM CONFIDENCE MAINLY HAS TO DO WITH THESE
UNCERTAINTIES FOR LATE TODAY AND OVERNIGHT TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: FOG MAY BE MORE WIDESPREAD 06Z TO 12Z MONDAY IF
THE RAIN TODAY AFFECTS A WIDER AREA.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M H H H H H H H H H H H
AFTER 12Z MONDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
330 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A SERIES OF DISTURBANCES ALOFT PASSING TODAY INTO TUESDAY. THE DEEPER
MOISTURE FOR THESE FEATURES TO TAP...MAINLY FROM MOUNTAINS ON EAST.
WEAK HIGH PRESSURE FOR WEDNESDAY THROUGH THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD MID/UPPER LEVEL TROF HERE FOR SEVERAL DAYS.
BASING FORECAST ON A STRONGER LEADING 500 MB VORT MAX PASSING FROM
SOUTHWEST TO NORTHEAST 12Z TO 16Z...EXITING THE NRN WV MOUNTAINS
AROUND 17Z. SO WILL BE FASTER IN INCREASING CLOUDS AND POPS EARLY
THIS MORNING OVER THE MOUNTAINOUS COUNTIES...PEAKING IN POCAHONTAS
COUNTY AROUND 15/16Z. DID NOT MENTION THUNDER. AS A RESULT OF THE
THICKENING AND LOWERING CLOUDS...REDUCE ANY THICK VALLEY FOG.
ONCE THAT FEATURE EXITS...HARD TO DETERMINE IF ANY SHOWERS DEVELOP
FURTHER WEST...ACROSS THE LOWLANDS DURING THE AFTERNOON AND
EVENING. SOME OF THE NEAR TERM MODELS...LIKE THE HRRR AND WRF-NMM
ARE DEVELOPING SHOWERS...MAYBE RELATED THE THE LOW LEVEL DEW POINT
GRADIENT BEING SHOVED BACK NORTHWEST TODAY. WILL TRY TO KEEP MOST
POPS IN WAKE OF THIS MORNINGS FEATURE...IN THE 20 OR LESS
CATEGORY...THINKING THE MAXIMUM IN MOISTURE IN THE OHIO VALLEY WILL
MOVE INTO NORTHERN HALF OF OHIO BY LATE THIS AFTERNOON...NOT THE
SOUTHERN COUNTIES.
00Z NAM WAS FASTER THAN THE 00Z GFS IN REDUCING MEAN RELATIVE
HUMIDITY IN THE COLUMN TONIGHT. FOR NOW...DO NOT SEE ANY REASON TO
ADJUST OUR 20/SLIGHT CHANCE POPS.
ALSO...DEPENDING ON THE RAIN TODAY...VALLEY FOG MAY HAVE TO BE
INSERTED FOR 06Z TO 12Z MONDAY...BUT A BIT PREMATURE AT THIS TIME.
COULD NOT HOLD MAXIMUM TEMPERATURES DOWN TOO MUCH TODAY...SINCE
HAVING THE MAIN SUPPORT EXITING BEFORE 18Z.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MODELS CONTINUE TO INDICATE 500MB TROUGH APPROACHING REGION HEADED
INTO SHORT TERM...WITH SEVERAL IMPULSES LIFTING THROUGH DURING THE
FIRST HALF OF THE WEEK. THE BEST MOISTURE IS GENERALLY IN THE WV
MOUNTAINS AND TO THE SOUTH EAST AND IT LOOKS LIKE THE MAIN SURFACE
LOW SHOULD ALSO STAY SOUTH EAST...SO KEPT HIGHEST POPS IN THE
MOUNTAINS DURING THE AFTERNOONS. MONDAY LOOKS LIKE THE DAY FOR THE
MOST COVERAGE OF PRECIP...AND HAVE CHANCE POPS FROM MOUNTAINS BACK
TO ABOUT THE OHIO RIVER...WITH SLIGHT CHANCE POPS INTO SE OHIO. POPS
LINGER INTO MONDAY NIGHT AS MODELS SHOW MOISTURE REMAINING WITH A
LITTLE RIPPLE ALOFT. SOME DIFFERENCES IN PLACEMENT BETWEEN
MODELS...BUT IN GENERAL SHOWING ANOTHER WEAK SHORTWAVE MOVING
THROUGH FOR TUESDAY AFTERNOON. BEST MOISTURE IS PROGGED TO BE
FARTHER EAST THAN ON MONDAY...SO KEPT CHANCE POPS MORE CLOSELY TIED
TO MOUNTAINS. MODELS SHOW RISING HEIGHTS HEADED INTO TUESDAY...AND
PUSH BEST MOISTURE EVEN FATHER EAST...SO LOOKS LIKE A DRIER DAY WITH
MAYBE JUST AN ISOLATED SHOWER IN MOUNTAINS.
ONLY MINIMAL CHANGES TO TEMPS THIS PACKAGE...STILL LOOKS LIKE A
GRADUAL WARMING TREND INTO MIDWEEK WITH NEAR NORMAL TEMPERATURES BY
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
USED A BLEND OF THE GFS AND ECMWF FOR WEDNESDAY THROUGH FRIDAY. THIS
LEAVES A WEAK HIGH PRESSURE SYSTEM OVER THE REGION...BUT POSSIBLY
ENOUGH MOISTURE TO FIRE SOME AFTERNOON SHOWERS/THUNDERSTORMS IN THE
MOUNTAINS. BY SATURDAY...SWITCHED TO A BLEND OF THE ECMWF AND GEFS
MEAN.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
WITH HIGH CLOUDS THICKENING AND LOWERING IN ADVANCE OF FIRST
WAVE...WAS A BIT MORE OPTIMISTIC ON THE FOG 06Z TO 12Z. STILL
ALLOWED FOR SOME LOCAL IFR IN NRN WV INCLUDING EKN DUE TO THE
THINNER CLOUDS.
THE 500 MB VORT MAX PASSES AROUND 15Z TO 18Z. BKW TO EKN CORRIDOR
SHOULD BE TOWARD THE WESTERN EDGE OF THE MAIN SHOWER SHIELD
ASSOCIATED WITH THIS WEAVE. HAVE POPS PEAKING ABOUT 15Z TO 17Z
AROUND POCAHONTAS COUNTY...BEFORE LOWERING AGAIN DURING THE 18Z TO
21Z PERIOD. HAVE CEILINGS LOWERING ALONG THE EASTERN SLOPES INTO
THE 2 TO 3 THSD FT BKN RANGE AND VSBY AROUND 5 MILES IN ANY RAIN
SHOWERS.
FURTHER WEST HAVE MID DECK AROUND 10 THSD FT AT 12Z BEFORE SOME 4 TO
6 THSD FT CEILINGS FROM BETWEEN 12Z TO 18Z.
ONCE THAT SUPPORT EXITS...HAVE TO GET A HANDLE ON THE AMOUNT AND
HEIGHTS OF THE CLOUDS FOR SUNDAY EVENING...SAY 00Z TO 06Z. WILL
LEAVE A SLIGHT CHANCE OF SHOWERS IN OVERNIGHT...WITH WEAKER
DISTURBANCES ALOFT...COMPARED TO TODAY. VISIBILITY IN THE MOUNTAIN
VALLEYS WILL LIKELY DEPEND ON ANY RAIN TODAY...SO WILL HAVE TO BE
FINE TUNED LATER TODAY. THE MEDIUM CONFIDENCE MAINLY HAS TO DO WITH
THESE UNCERTAINTIES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: THICKER FOG IN RIVER VALLEYS IF CLOUDS REMAIN
THIN LONGER DURING THE PREDAWN. FOG MAY FORM QUICKER LATE SUNDAY
EVENING IF RAIN IS MORE WIDESPREAD IN THE MOUNTAINOUS COUNTIES
TODAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SUN 08/19/12
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L M H H H H H H H
PKB CONSISTENCY M M M M H H H H H H H H
CKB CONSISTENCY L L M M H H H H H H H H
AFTER 06Z MONDAY...
AREAS OF FOG MAY CAUSE IFR 06Z TO 12Z MONDAY DEPENDING ON CLOUD
COVER AND PREVIOUS RAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...RPY
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1115 PM EDT MON AUG 20 2012
.SYNOPSIS...
A LARGE UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE U.S. WILL
DOMINATE THE REGIONAL WEATHER PATTERN THROUGH WEDNESDAY.
DISTURBANCES ALOFT WILL ROTATE AROUND THE UPPER LEVEL TROUGH AND
KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST EARLY THIS WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
EVENING WATER VAPOR LOOP SHOWING SHORTWAVE LIFTING NE INTO WESTERN
PA. LG SCALE FORCING AHEAD OF THIS FEATURE...COMBINED WITH
RESIDUAL INSTABILITY...RESULTING IN A BKN LINE OF SHRA/TSRA
ACROSS THE CENTRAL MTNS. MDL-SIMULATED RADAR DATA SUGGESTS THIS BAND
OF SHRA/TSRA WILL DWINDLE AS IT ENCOUNTERS A STABLE AIR MASS OVER
THE SUSQ VALLEY BTWN 03Z-06Z. WILL REMOVE LAST MENTION OF PRECIP
OVR THE EASTERN ZONES SHORTLY AFTER 06Z...AS SHORTWAVE EXITS THE
AREA.
CLEARING SKIES...A LGT WIND AND WET GROUND ALREADY RESULTING IN
PATCHY FOG AT 0230Z AND EXPECT IT TO BECOME WIDESPREAD AND LOCALLY
DENSE LATE TONIGHT. GFS EXPERIENCING KNOWN ISSUE OF LOW LVL TEMPS
BEING TOO COOL. THUS...HAVE USED A BLEND OF MET AND RUC DATA FOR
OVERNIGHT LOWS...WHICH SHOULD RANGE FROM THE U40S NW MTNS...TO
M/U50S ACROSS THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
FOG SHOULD BURN OFF TO MSUNNY SKIES BY LATE AM. HOWEVER...DIURNAL
HEATING COMBINED WITH APPROACH OF UPPER LVL TROF SHOULD YIELD
INCREASING CU AND SCT SHRA/TSRA BY AFTN. PWAT VALUES ARE LOWER
THAN MONDAY...SO COVERAGE OF PRECIP SHOULD BE LESS WIDESPREAD.
ELEVATED TERRAIN AND PROXIMITY TO UPPER TROF WILL FAVOR THE
WESTERN AND CENTRAL MTNS FOR HIGHER /CHC/ POPS...WHILE ONLY WIDELY
SCT /SCHC/ POPS EXPECTED ACROSS THE EASTERN COUNTIES. MORE
SUNSHINE WILL RESULT IN A SLIGHTLY WARMER DAY THAN TODAY...WITH
MDL 8H TEMPS SUPPORTIVE OF HIGHS FROM THE L/M70S OVR THE ALLEGHENIES...TO
ARND 80F OVR THE SUSQ VALLEY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE NORTHEAST U.S. WILL REMAIN IN AN UPPER TROUGH THROUGH LATE
WEEK. HOWEVER...SURFACE HIGH PRESSURE WILL INFILTRATE THE REGION
DURING THE DAY WEDNESDAY. LEFT AN ISOLATED THREAT FOR A
THUNDERSTORM OVER THE EASTER CWA WEDNESDAY AFTERNOON BUT A
MAJORITY OF THE FORECAST AREA WILL SEE DRY WEATHER.
THE UPPER TROUGH FILLS AND WE MOVE TO A MORE ZONAL FLOW ON
THURSDAY. WITH SURFACE HIGH PRESSURE...TEMPERATURES WILL RISE TO
SLIGHTLY ABOVE SEASONAL AVERAGES.
A SLIGHTLY MUDDIED PICTURE SHOWN BY THE EXTENDED MODELS WITH A
FEW UPPER LEVEL RIPPLES MOVE THROUGH THE REGION AS A 500 MB
HEIGHTS REMAIN HIGH OVER THE SOUTHWEST U.S. TIMING OF ANY AREAS OF
PRECIP IS DIFFICULT THIS FAR OUT SO LEFT A MORE OPTIMISTIC OUTLOOK
UNTIL SOMETHING GROWS HORNS.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
MINOR ADJUSTMENTS TO 03Z TAFS.
SKIES STARTING TO CLEAR TO THE WEST...SO STILL EXPECT FOG
TO FORM...PERHAPS NOT QUITE AS FAST AS I HAD IN THE 00Z
TAFS.
SHOWERS AND STORMS JUST ABOUT GONE NOW.
EARLIER DISCUSSION BELOW.
MAIN ISSUE WILL BE DENSE FOG LATE...IFR AND LIFR CONDITIONS
LIKELY.
EXPECT THINGS TO IMPROVE BY MID MORNING ACROSS MOST OF THE
AREA ON TUE. LOWER CHC FOR SHOWERS AND STORMS ON TUE THAN
TODAY.
HOWEVER...SOME CHC FOR SHOWERS AND STORMS TUESDAY NIGHT INTO
WED...AS ANOTHER UPPER LVL SYSTEM ROTATES AROUND THE DEEP
VORTEX.
ALONG WITH THE CHC OF SHOWERS AND STORMS TUESDAY NIGHT...FOG
WILL LIKELY FORM AGAIN.
IMPROVING CONDITIONS STILL EXPECTED LATER IN THE WEEK...AS THE
UPPER LVL FLOW BECOMES MORE ZONAL...THAT IS WEST TO EAST...FOR
A CHANGE...AND TEMPS WARM SOME.
OUTLOOK...
THU-SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CERU/STEINBUGL
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...TYBURSKI
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1046 PM EDT MON AUG 20 2012
.SYNOPSIS...
A LARGE UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE U.S. WILL
DOMINATE THE REGIONAL WEATHER PATTERN THROUGH WEDNESDAY.
DISTURBANCES ALOFT WILL ROTATE AROUND THE UPPER LEVEL TROUGH AND
KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST EARLY THIS WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
EVENING WATER VAPOR LOOP SHOWING SHORTWAVE LIFTING NE INTO WESTERN
PA. LG SCALE FORCING AHEAD OF THIS FEATURE...COMBINED WITH
RESIDUAL INSTABILITY...RESULTING IN A BKN LINE OF SHRA/TSRA
ACROSS THE CENTRAL MTNS. MDL-SIMULATED RADAR DATA SUGGESTS THIS BAND
OF SHRA/TSRA WILL DWINDLE AS IT ENCOUNTERS A STABLE AIR MASS OVER
THE SUSQ VALLEY BTWN 03Z-06Z. WILL REMOVE LAST MENTION OF PRECIP
OVR THE EASTERN ZONES SHORTLY AFTER 06Z...AS SHORTWAVE EXITS THE
AREA.
CLEARING SKIES...A LGT WIND AND WET GROUND ALREADY RESULTING IN
PATCHY FOG AT 0230Z AND EXPECT IT TO BECOME WIDESPREAD AND LOCALLY
DENSE LATE TONIGHT. GFS EXPERIENCING KNOWN ISSUE OF LOW LVL TEMPS
BEING TOO COOL. THUS...HAVE USED A BLEND OF MET AND RUC DATA FOR
OVERNIGHT LOWS...WHICH SHOULD RANGE FROM THE U40S NW MTNS...TO
M/U50S ACROSS THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
FOG SHOULD BURN OFF TO MSUNNY SKIES BY LATE AM. HOWEVER...DIURNAL
HEATING COMBINED WITH APPROACH OF UPPER LVL TROF SHOULD YIELD
INCREASING CU AND SCT SHRA/TSRA BY AFTN. PWAT VALUES ARE LOWER
THAN MONDAY...SO COVERAGE OF PRECIP SHOULD BE LESS WIDESPREAD.
ELEVATED TERRAIN AND PROXIMITY TO UPPER TROF WILL FAVOR THE
WESTERN AND CENTRAL MTNS FOR HIGHER /CHC/ POPS...WHILE ONLY WIDELY
SCT /SCHC/ POPS EXPECTED ACROSS THE EASTERN COUNTIES. MORE
SUNSHINE WILL RESULT IN A SLIGHTLY WARMER DAY THAN TODAY...WITH
MDL 8H TEMPS SUPPORTIVE OF HIGHS FROM THE L/M70S OVR THE ALLEGHENIES...TO
ARND 80F OVR THE SUSQ VALLEY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE NORTHEAST U.S. WILL REMAIN IN AN UPPER TROUGH THROUGH LATE
WEEK. HOWEVER...SURFACE HIGH PRESSURE WILL INFILTRATE THE REGION
DURING THE DAY WEDNESDAY. LEFT AN ISOLATED THREAT FOR A
THUNDERSTORM OVER THE EASTER CWA WEDNESDAY AFTERNOON BUT A
MAJORITY OF THE FORECAST AREA WILL SEE DRY WEATHER.
THE UPPER TROUGH FILLS AND WE MOVE TO A MORE ZONAL FLOW ON
THURSDAY. WITH SURFACE HIGH PRESSURE...TEMPERATURES WILL RISE TO
SLIGHTLY ABOVE SEASONAL AVERAGES.
A SLIGHTLY MUDDIED PICTURE SHOWN BY THE EXTENDED MODELS WITH A
FEW UPPER LEVEL RIPPLES MOVE THROUGH THE REGION AS A 500 MB
HEIGHTS REMAIN HIGH OVER THE SOUTHWEST U.S. TIMING OF ANY AREAS OF
PRECIP IS DIFFICULT THIS FAR OUT SO LEFT A MORE OPTIMISTIC OUTLOOK
UNTIL SOMETHING GROWS HORNS.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AS EXPECTED...MOST OF THE ACTIVITY SO FAR HAS BEEN ACROSS THE
LOWER SUSQUEHANNA VALLEY.
HOWEVER...STILL SOME SHOWERS AND STORMS TO THE WEST.
EXPECT MOST OF THIS ACTIVITY TO BE GONE BY LATE EVENING.
MAIN ISSUE WILL BE DENSE FOG LATE...IFR AND LIFR CONDITIONS
LIKELY.
EXPECT THINGS TO IMPROVE BY MID MORNING ACROSS MOST OF THE
AREA ON TUE. LOWER CHC FOR SHOWERS AND STORMS ON TUE THAN
TODAY.
HOWEVER...SOME CHC FOR SHOWERS AND STORMS TUESDAY NIGHT INTO
WED...AS ANOTHER UPPER LVL SYSTEM ROTATES AROUND THE DEEP
VORTEX.
ALONG WITH THE CHC OF SHOWERS AND STORMS TUESDAY NIGHT...FOG
WILL LIKELY FORM AGAIN.
IMPROVING CONDITIONS STILL EXPECTED LATER IN THE WEEK...AS THE
UPPER LVL FLOW BECOMES MORE ZONAL...THAT IS WEST TO EAST...FOR
A CHANGE...AND TEMPS WARM SOME.
OUTLOOK...
THU-SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CERU/STEINBUGL
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...TYBURSKI
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
835 PM EDT MON AUG 20 2012
.SYNOPSIS...
A LARGE UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE U.S. WILL
DOMINATE THE REGIONAL WEATHER PATTERN THROUGH WEDNESDAY.
DISTURBANCES ALOFT WILL ROTATE AROUND THE UPPER LEVEL TROUGH AND
KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST EARLY THIS WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
EVENING WATER VAPOR LOOP SHOWING SHORTWAVE OVR E OHIO....LIFTING
NE INTO PA. LG SCALE FORCING AHEAD OF THIS FEATURE...COMBINED
WITH LATE DAY HEATING/INSTABILITY...RESULTING IN WIDELY SCT
SHRA/TSRA ACROSS WESTERN PA...WHERE MOISTURE IS LIMITED...TO A
SOLID LINE OF SHRA ACROSS THE LOWER SUSQ VALLEY...WHERE PWATS ARE
MUCH HIGHER. MDL-SIMULATED RADAR DATA SUGGESTS BAND OF SHRA/TSRA
OVR THE LOWER SUSQ WILL CLEAR LANCASTER CO BY 01Z-02Z.
ACROSS THE NW MTNS...HAVE REMOVED MENTION OF PRECIP TONIGHT...AS
SFC DWPTS HAVE DROPPED IN WAKE OF SFC TROF PASSAGE. ELSEWHERE...EXPECT
DIMINISHING COVERAGE AS THE SUN SETS AND WILL REMOVE ALL MENTION
OF SHRA UPON PASSAGE OF SHORTWAVE...WHICH SHOULD OCCUR BY ARND
MIDNIGHT OVR THE CENTRAL MTNS AND SHORTLY AFTER 06Z ACROSS THE SE
ZONES.
CLEARING SKIES...A LGT WIND AND WET GROUND SHOULD RESULT IN
WIDESPREAD FOG LATE TONIGHT...SOME OF WHICH IS LIKELY TO BE DENSE.
GFS EXPERIENCING KNOWN ISSUE OF LOW LVL TEMPS BEING TOO COOL.
THUS...HAVE USED A BLEND OF MET AND RUC DATA FOR OVERNIGHT
LOWS...WHICH SHOULD RANGE FROM THE U40S NW MTNS...TO M/U50S ACROSS
THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
FOG SHOULD BURN OFF TO MSUNNY SKIES BY LATE AM. HOWEVER...DIURNAL
HEATING COMBINED WITH APPROACH OF UPPER LVL TROF SHOULD YIELD
INCREASING CU AND SCT SHRA/TSRA BY AFTN. PWAT VALUES ARE LOWER
THAN MONDAY...SO COVERAGE OF PRECIP SHOULD BE LESS WIDESPREAD.
ELEVATED TERRAIN AND PROXIMITY TO UPPER TROF WILL FAVOR THE
WESTERN AND CENTRAL MTNS FOR HIGHER /CHC/ POPS...WHILE ONLY WIDELY
SCT /SCHC/ POPS EXPECTED ACROSS THE EASTERN COUNTIES. MORE
SUNSHINE WILL RESULT IN A SLIGHTLY WARMER DAY THAN TODAY...WITH
MDL 8H TEMPS SUPPORTIVE OF HIGHS FROM THE L/M70S OVR THE ALLEGHENIES...TO
ARND 80F OVR THE SUSQ VALLEY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE NORTHEAST U.S. WILL REMAIN IN AN UPPER TROUGH THROUGH LATE
WEEK. HOWEVER...SURFACE HIGH PRESSURE WILL INFILTRATE THE REGION
DURING THE DAY WEDNESDAY. LEFT AN ISOLATED THREAT FOR A
THUNDERSTORM OVER THE EASTER CWA WEDNESDAY AFTERNOON BUT A
MAJORITY OF THE FORECAST AREA WILL SEE DRY WEATHER.
THE UPPER TROUGH FILLS AND WE MOVE TO A MORE ZONAL FLOW ON
THURSDAY. WITH SURFACE HIGH PRESSURE...TEMPERATURES WILL RISE TO
SLIGHTLY ABOVE SEASONAL AVERAGES.
A SLIGHTLY MUDDIED PICTURE SHOWN BY THE EXTENDED MODELS WITH A
FEW UPPER LEVEL RIPPLES MOVE THROUGH THE REGION AS A 500 MB
HEIGHTS REMAIN HIGH OVER THE SOUTHWEST U.S. TIMING OF ANY AREAS OF
PRECIP IS DIFFICULT THIS FAR OUT SO LEFT A MORE OPTIMISTIC OUTLOOK
UNTIL SOMETHING GROWS HORNS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS EXPECTED...MOST OF THE ACTIVITY SO FAR HAS BEEN ACROSS THE
LOWER SUSQUEHANNA VALLEY.
HOWEVER...STILL SOME SHOWERS AND STORMS TO THE WEST.
EXPECT MOST OF THIS ACTIVITY TO BE GONE BY LATE EVENING.
MAIN ISSUE WILL BE DENSE FOG LATE...IFR AND LIFR CONDITIONS
LIKELY.
EXPECT THINGS TO IMPROVE BY MID MORNING ACROSS MOST OF THE
AREA ON TUE. LOWER CHC FOR SHOWERS AND STORMS ON TUE THAN
TODAY.
HOWEVER...SOME CHC FOR SHOWERS AND STORMS TUESDAY NIGHT INTO
WED...AS ANOTHER UPPER LVL SYSTEM ROTATES AROUND THE DEEP
VORTEX.
ALONG WITH THE CHC OF SHOWERS AND STORMS TUESDAY NIGHT...FOG
WILL LIKELY FORM AGAIN.
IMPROVING CONDITIONS STILL EXPECTED LATER IN THE WEEK...AS THE
UPPER LVL FLOW BECOMES MORE ZONAL...THAT IS WEST TO EAST...FOR
A CHANGE...AND TEMPS WARM SOME.
OUTLOOK...
THU-SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CERU/STEINBUGL
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...TYBURSKI
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1005 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A SEASONABLY STRONG UPPER LEVEL TROUGH OVER THE EASTERN HALF OF
THE U.S. WILL DOMINATE THE REGIONAL WEATHER PATTERN INTO THE
MIDDLE OF THE UPCOMING WEEK. SEVERAL WAVES OF LOW PRESSURE WILL
RIPPLE NORTHEASTWARD FROM THE GULF COAST ALONG A WAVY FRONTAL
BOUNDARY DRAPED ACROSS THE SOUTHEAST STATES AND SOUTHERN MID-
ATLANTIC. HIGH PRESSURE SHOULD RETURN TO THE AREA BY THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
CONVECTION DEVELOPING EARLY THIS MORNING AT NOSE OF HIGH THETA-E
RIDGE INTO WRN PA. THE SHOWERS SEEM TO HAVE SOME OROGRAPHIC
HELP/GENESIS...BUT ARE ALSO DISCONNECTED TO SFC SEEN IN STABLE
57/53F OB AT KAOO. WILL BUMP POPS A LITTLE AND WIDEN SCOPE A
LITTLE. LATEST RUC AND HRRR RUNS SPREAD THOSE SHRA/TSRA TO THE
NORTH AS THE MOISTURE ALOFT GETS BETTER AND UPGLIDE/ELEV INSTAB
COMBINES WITH HEATING/SFC INSTABILITY - ESP IN NWRN COS. SHIELD OF
GENERALLY LIGHT STRATIFORM RAIN WILL MOST LIKELY CONTINUE NE BUT
LIGHTEN UP AS DIURNAL CONVECTION DEVELOPS TO THE S - OVER VA/SRN
MD...ROBBING THE ERN COS OF BEST/DEEPEST MOISTURE. LAPSE RATES GET
STEEPER ALOFT THIS AFTN OVER THE WEST AS WELL AS THE 5H TROF MOVES
CLOSER. THE LOSS OF DAYTIME HEATING SHOULD SPELL AN AND TO THIS
ACTIVITY BY TNT...WITH PCPN FOCUS THEN SHIFTING TO SE PA.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE SECOND S/W CURRENTLY MOVG INTO THE SRN APPLCHNS WILL SPAWN A
WEAK SFC LOW OVER SC BY 21Z AND TRACK NEWD ACRS THE SRN MID-ATLC
STATES THRU THE END OF THE PD. THERE ARE SOME CONTINUING MDL DIFFS
WITH THE TRACK/PLACEMENT OF THE SFC LOW BY 12Z MON...WITH THE
UKMET THE SLOWEST SOLN AND NAM/ECMWF LOW POSITION NW OF THE
GFS/GEM. GIVEN THE UNCERTAINTY...A COMPROMISE OF EC/NAM/GFS/GEM IS
PREFERRED BY HPC AND PUTS THE LOW JUST E OF KWAL AT F36. BACKING
FLOW REGIME WILL TAP POOL OF HI PWAT OFF THE SE COAST AND SHOULD
WRAP OVRRNG PCPN N/NWWD FM THE DELMARVA BACK INTO SE PA ON NW SIDE
LOW TRACK LATE TNT INTO EARLY MON. HOWEVER DUE TO THE SPREAD IN
SOLNS WILL KEEP POPS MAINLY IN THE HIGH CHC RANGE OVR THE LWR SUSQ
VLY.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
FANTASTIC AGREEMENT AMONGST ALL FORECAST MODELS AND ENSEMBLE MEANS
OF THE MAJOR UPPER LEVEL FEATURES LEADS TO A HIGHER-THAN-NORMAL
CONFIDENCE FORECAST THROUGH THE MID RANGE AND FOR THE LONG TERM.
A HIGHLY ANOMALOUS UPPER TROUGH OVER THE CENTRAL AND SOUTHERN
STATES AT THE START OF THE PERIOD WILL FILL AND LIFT EASTWARD
DURING THE MID- WEEK. THUS...TEMPS SHOULD BE SLIGHTLY BELOW
NORMAL. PATTERN IS THEN MAINLY ZONAL. SFC FEATURES WILL DRIVE
MINOR FORECAST UNCERTAINTIES IN THE FIRST FEW DAYS...THOUGH. A
STALLED FRONT OVER THE SOUTHERN MID-ATLANTIC COULD BUCKLE A BIT
NORTHWARD AS A MOISTURE PLUME WITH A CONNECTION TO DEEP TROPICAL
MOISTURE OVER MEXICO IS DRAWN NORTHWARD ON THE EASTERN SIDE OF THE
UPPER TROUGH. A WAVE HAS BEEN FORECAST TO DEVELOP ALONG THE FRONT
FOR THE PAST FEW RUNS...AND SEE NO REASON TO DISCOUNT THAT WITH
SUCH A GOOD FEED ALOFT. THE CHANCES OF PRECIP ARE VERY MUCH IN
QUESTION...THOUGH. WILL HOLD WITH MUCH OF THE CURRENT
FORECAST...AND KEEP CHC RANGE POPS IN FOR MAINLY THE EAST SUN
NIGHT - MON NIGHT. AS BEFORE...HIGHEST POPS OF LIKELIES WILL BE
OVER THE SERN COS FOR MONDAY. NO THREAT FOR HEAVY RAIN WITH NO
REAL LOCAL FOCUS...NO PWAT ANOMALIES ACCORDING TO GEFS...AND THE
WAVE ALONG THE FRONT SHOULD BE MOBILE.
A SHORT WAVE STEMMING FROM THIS UPPER LEVEL LOW SHOULD MAKE ITS
WAY THROUGH TUESDAY AFTERNOON. DEPENDING ON TIMING...AND IF ITS
CONGRUENT WITH DIURNAL HEATING...THOUGH MAX TEMPS ARE SLIGHTLY
BELOW NORMAL...SHOULD ALLOW FOR SCT TSRA WITH COOL TEMPS ALOFT AS
THE TROUGH AXIS WILL BE OVERHEAD OR JUST APPROACHING. A STALLED
SFC LOW ON WEDNESDAY MAY BRING ENOUGH EASTERLY FLOW TO CAUSE
SHOWERS ALONG THE EASTERN PORTION OF THE CWA ON WEDNESDAY...THEN
MUCH OF THE WEEK LOOKS DRY AS A SFC ANTICYCLONE SETTLES IN FOR THE
LONG HAUL. D7/D8 WILL SEE THE RETURN OF VERY LOW POPS TO THE WEST
AS THE HIGH SLIDES TO THE EAST INTO THE WESTERN ATLANTIC.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
A BROAD UPPER LEVEL TROUGH EXTENDING SWD FROM JAMES BAY VORTEX
WILL PERSIST THROUGH EARLY NEXT WEEK. SEVERAL IMPULSES WILL
TRANSLATE AROUND THE BASE OF THE TROUGH THRU THE MS/TN/OH VLYS AND
INTERACT WITH A WAVY FRONTAL BOUNDARY STRETCHING FROM THE DEEP
SOUTH INTO THE SRN MID-ATLC STATES.
THERE IS STILL A LARGE SPREAD IN PCPN DETAILS...AND THIS TRANSLATES
INTO A LOW CONFIDENCE AVN FCST. IN GENERAL...WENT WITH A GRADUAL
LOWERING OF CLOUD BASES/VISBYS INTO MVFR RANGE TONIGHT. CONSENSUS
OF MDL DATA WOULD TEND TO FAVOR THE S-CENTRAL/SERN TERMINALS FOR
THE HIGHEST PROBABILITY FOR PCPN AND HAVE INSERTED VCSH. SOME IFR
CONDS ARE POSSIBLE TONIGHT BUT NOT CONFIDENT ENOUGH TO FCST IN THE
12Z TAFS.
OUTLOOK...
MON-TUE...VFR/MVFR WITH PERIODS OF LGT PCPN PSBL ESP SRN AIRFIELDS.
WED-THUR...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DANGELO/FITZGERALD/CERU
AVIATION...DANGELO/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
205 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE WILL SLIDE EASTWARD FROM THE LOWER
LAKES EARLY THIS MORNING. THE LARGE SCALE PATTERN INTO EARLY NEXT WEEK
WILL REMAIN DOMINATED BY A DEEP UPPER LEVEL TROUGH ENCOMPASSING
MUCH OF EASTERN NORTH AMERICA. A WAVE OF LOW PRESSURE IS FORECAST
TRACK NORTHEASTWARD ACROSS THE MID-ATLANTIC STATES LATER SUNDAY
THROUGH MONDAY. HIGH PRESSURE SHOULD RETURN TO THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CIRRUS CONTINUES TO STREAM OVER CENTRAL PA THIS EVENING...AND HAVE
THUS RAISED MIN TEMPS A BIT...ESP ACROSS THE SW PORTION OF CWA.
BASED ON HRRR AND DEWPOINT DEPRESSIONS...HAVE KEPT PATCHY VALLEY
FOG IN THE FCST FOR LATE TONIGHT...ESP OVR THE NW MTNS. HAVE
ADDED PATCHY FOG TO THE LOW LYING REGIONS ALONG THE LOWER
SUSQ...GIVEN THE CALM WINDS AND THE DEWPOINT DEPRESSIONS. HOWEVER...IF
APPROACHING CIRRUS SHIELD IS THICK ENOUGH...MAY HAVE TO REMOVE IT.
FOR THOSE AREAS THAT REMAIN MCLEAR... THIS COULD BE THE COOLEST
NIGHT SINCE LAST JUNE WITH LOWS RANGING FROM THE L40S IN THE
COOLEST HOLLOWS OF THE NORTH...TO THE M50S ACROSS THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
FAST-MOVING SHORTWAVE...ROUNDING BASE OF UPPER TROF OVR THE MISS
VALLEY THIS EVENING...SHOULD LIFT NE ACROSS OUR REGION DURING LATE
AM/EARLY AFTN SUNDAY. ALTHOUGH LL FLOW WILL SHIFT TO THE SOUTH
AHEAD OF THIS FEATURE...MOISTURE WILL REMAIN LIMITED. BEST CHC FOR
A FEW -SHRA WILL BE ACROSS SOUTH CENTRAL PA DURING THE LATE
AM/EARLY AFTN HOURS. TOWARD EVENING...EXPECT WANING CHC OF SHRA
ACROSS THE EAST. HOWEVER...STEEPENING LPS RTS AHEAD OF NEXT
SHORTWAVE SHOULD BE SUFFICIENT TO PRODUCE ISOLD EVENING SHRA OR
TSRA ACROSS THE W MTNS BEFORE SUNSET. DESPITE MORE CLOUD
COVER...HIGH TEMPS SUNDAY SHOULD BE SIMILAR TO SAT...RANGING FROM
THE L70S OVR THE ALLEGHENIES...TO NR 80F IN THE SUSQ VALLEY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
FANTASTIC AGREEMENT AMONGST ALL FORECAST MODELS AND ENSEMBLE MEANS
OF THE MAJOR UPPER LEVEL FEATURES LEADS TO A HIGHER-THAN-NORMAL
CONFIDENCE FORECAST FOR THE LONG TERM. A HIGHLY ANOMALOUS UPPER
TROUGH OVER THE CENTRAL AND SOUTHERN STATES AT THE START OF THE
PERIOD WILL FILL AND LIFT EASTWARD DURING THE MID-WEEK.
THUS...TEMPS SHOULD BE SLIGHTLY BELOW NORMAL. PATTERN IS THEN
MAINLY ZONAL. SFC FEATURES WILL DRIVE MINOR FORECAST UNCERTAINTIES
IN THE FIRST FEW DAYS...THOUGH. A STALLED FRONT OVER THE SOUTHERN
MID-ATLANTIC COULD BUCKLE A BIT NORTHWARD AS A MOISTURE PLUME
WITH A CONNECTION TO DEEP TROPICAL MOISTURE OVER MEXICO IS DRAWN
NORTHWARD ON THE EASTERN SIDE OF THE UPPER TROUGH. A WAVE HAS BEEN
FORECAST TO DEVELOP ALONG THE FRONT FOR THE PAST FEW RUNS...AND
SEE NO REASON TO DISCOUNT THAT WITH SUCH A GOOD FEED ALOFT. THE
CHANCES OF PRECIP ARE VERY MUCH IN QUESTION...THOUGH. WILL HOLD
WITH MUCH OF THE CURRENT FORECAST...AND KEEP CHC RANGE POPS IN FOR
MAINLY THE EAST SUN NIGHT - MON NIGHT. AS BEFORE...HIGHEST POPS OF
LIKELIES WILL BE OVER THE SERN COS FOR MONDAY. NO THREAT FOR HEAVY
RAIN WITH NO REAL LOCAL FOCUS...AND THE WAVE ALONG THE FRONT
SHOULD BE MOBILE. TUESDAY AFTERNOON MAY HOLD SCT TSRA WITH COOL
TEMPS ALOFT AS THE TROUGH AXIS WILL BE OVERHEAD OR JUST
APPROACHING. THEN MUCH OF THE WEEK LOOKS DRY AS A SFC ANTICYCLONE
SETTLES IN FOR THE LONG HAUL. D7/D8 WILL SEE THE RETURN OF VERY
LOW POPS TO THE WEST AS THE HIGH SLIDES TO THE EAST INTO THE
WESTERN ATLANTIC.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
IR SATL LOOP SHOWS MULTI-LYRD CLOUD SHIELD STREAMING ENEWD FM THE
OH VLY AND CENTRAL APPLCHNS. THESE CLOUDS WILL CONTINUE TO OVERSPREAD
THE REGION THRU THE PREDAWN HOURS AND LIMIT FURTHER DIURNAL
COOLING. THEREFORE...REMOVED MUCH OF THE FOG IN THE PREVIOUS TAFS
WITH THE BEST CHANCE OF RESTRICTIONS LKLY AT IPT/BFD.
A BROAD UPPER LEVEL TROUGH EXTENDING SWD FROM JAMES BAY VORTEX
WILL PERSIST THROUGH EARLY NEXT WEEK. SEVERAL IMPULSES WILL
TRANSLATE AROUND THE BASE OF THE TROUGH THRU THE MS/TN/OH
VLYS AND INTERACT WITH A WAVY FRONTAL BOUNDARY STRETCHING FROM THE
DEEP SOUTH INTO THE SRN MID-ATLC STATES. THERE IS A LARGE SPREAD IN
PCPN DETAILS ASSOCIATED WITH THESE FEATURES...AND THIS TRANSLATES
INTO A LOW CONFIDENCE AVN FCST. IN GENERAL...WENT WITH A GRADUAL
LOWERING OF CLOUD BASES INTO THE LOW END VFR OR MVFR RANGE BY THE
END OF THE PD/06Z MON. CONSENSUS OF MDL DATA WOULD TEND TO FAVOR
THE S-CENTRAL/SERN TERMINALS FOR THE HIGHEST PROBABILITY FOR PCPN
THRU EARLY NEXT WEEK.
OUTLOOK...
MON-TUE...VFR/MVFR WITH PERIODS OF LGT PCPN PSBL ESP SRN AIRFIELDS.
WED-THUR...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...FITZGERALD/CERU
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...DANGELO
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
127 AM EDT SUN AUG 19 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE WILL SLIDE EASTWARD FROM THE LOWER
LAKES EARLY THIS MORNING. THE LARGE SCALE PATTERN INTO EARLY NEXT WEEK
WILL REMAIN DOMINATED BY A DEEP UPPER LEVEL TROUGH ENCOMPASSING
MUCH OF EASTERN NORTH AMERICA. A WAVE OF LOW PRESSURE IS FORECAST
TRACK NORTHEASTWARD ACROSS THE MID-ATLANTIC STATES LATER SUNDAY
THROUGH MONDAY. HIGH PRESSURE SHOULD RETURN TO THE AREA BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CIRRUS CONTINUES TO STREAM OVER CENTRAL PA THIS EVENING...AND HAVE
THUS RAISED MIN TEMPS A BIT...ESP ACROSS THE SW PORTION OF CWA.
BASED ON HRRR AND DEWPOINT DEPRESSIONS...HAVE KEPT PATCHY VALLEY
FOG IN THE FCST FOR LATE TONIGHT...ESP OVR THE NW MTNS. HAVE
ADDED PATCHY FOG TO THE LOW LYING REGIONS ALONG THE LOWER
SUSQ...GIVEN THE CALM WINDS AND THE DEWPOINT DEPRESSIONS. HOWEVER...IF
APPROACHING CIRRUS SHIELD IS THICK ENOUGH...MAY HAVE TO REMOVE IT.
FOR THOSE AREAS THAT REMAIN MCLEAR... THIS COULD BE THE COOLEST
NIGHT SINCE LAST JUNE WITH LOWS RANGING FROM THE L40S IN THE
COOLEST HOLLOWS OF THE NORTH...TO THE M50S ACROSS THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
FAST-MOVING SHORTWAVE...ROUNDING BASE OF UPPER TROF OVR THE MISS
VALLEY THIS EVENING...SHOULD LIFT NE ACROSS OUR REGION DURING LATE
AM/EARLY AFTN SUNDAY. ALTHOUGH LL FLOW WILL SHIFT TO THE SOUTH
AHEAD OF THIS FEATURE...MOISTURE WILL REMAIN LIMITED. BEST CHC FOR
A FEW -SHRA WILL BE ACROSS SOUTH CENTRAL PA DURING THE LATE
AM/EARLY AFTN HOURS. TOWARD EVENING...EXPECT WANING CHC OF SHRA
ACROSS THE EAST. HOWEVER...STEEPENING LPS RTS AHEAD OF NEXT
SHORTWAVE SHOULD BE SUFFICIENT TO PRODUCE ISOLD EVENING SHRA OR
TSRA ACROSS THE W MTNS BEFORE SUNSET. DESPITE MORE CLOUD
COVER...HIGH TEMPS SUNDAY SHOULD BE SIMILAR TO SAT...RANGING FROM
THE L70S OVR THE ALLEGHENIES...TO NR 80F IN THE SUSQ VALLEY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
FANTASTIC AGREEMENT AMONGST ALL FORECAST MODELS AND ENSEMBLE MEANS
OF THE MAJOR UPPER LEVEL FEATURES LEADS TO A HIGHER-THAN-NORMAL
CONFIDENCE FORECAST FOR THE LONG TERM. A HIGHLY ANOMALOUS UPPER
TROUGH OVER THE CENTRAL AND SOUTHERN STATES AT THE START OF THE
PERIOD WILL FILL AND LIFT EASTWARD DURING THE MID-WEEK.
THUS...TEMPS SHOULD BE SLIGHTLY BELOW NORMAL. PATTERN IS THEN
MAINLY ZONAL. SFC FEATURES WILL DRIVE MINOR FORECAST UNCERTAINTIES
IN THE FIRST FEW DAYS...THOUGH. A STALLED FRONT OVER THE SOUTHERN
MID-ATLANTIC COULD BUCKLE A BIT NORTHWARD AS A MOISTURE PLUME
WITH A CONNECTION TO DEEP TROPICAL MOISTURE OVER MEXICO IS DRAWN
NORTHWARD ON THE EASTERN SIDE OF THE UPPER TROUGH. A WAVE HAS BEEN
FORECAST TO DEVELOP ALONG THE FRONT FOR THE PAST FEW RUNS...AND
SEE NO REASON TO DISCOUNT THAT WITH SUCH A GOOD FEED ALOFT. THE
CHANCES OF PRECIP ARE VERY MUCH IN QUESTION...THOUGH. WILL HOLD
WITH MUCH OF THE CURRENT FORECAST...AND KEEP CHC RANGE POPS IN FOR
MAINLY THE EAST SUN NIGHT - MON NIGHT. AS BEFORE...HIGHEST POPS OF
LIKELIES WILL BE OVER THE SERN COS FOR MONDAY. NO THREAT FOR HEAVY
RAIN WITH NO REAL LOCAL FOCUS...AND THE WAVE ALONG THE FRONT
SHOULD BE MOBILE. TUESDAY AFTERNOON MAY HOLD SCT TSRA WITH COOL
TEMPS ALOFT AS THE TROUGH AXIS WILL BE OVERHEAD OR JUST
APPROACHING. THEN MUCH OF THE WEEK LOOKS DRY AS A SFC ANTICYCLONE
SETTLES IN FOR THE LONG HAUL. D7/D8 WILL SEE THE RETURN OF VERY
LOW POPS TO THE WEST AS THE HIGH SLIDES TO THE EAST INTO THE
WESTERN ATLANTIC.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
NO CHANGE TO 03Z TAF PACKAGE.
EARLIER DISCUSSION BELOW.
SPENT SOME TIME AROUND 21Z ADJUSTING THE FCST. WHILE SOME CU AND
SC MAY MOVE INTO CENTRAL PA SUNDAY MORNING...HARD TO SEE FOG
STAYING AROUND VERY LONG. THUS 21Z TAFS ARE ABOUT THE SAME AS THE
00Z TAFS...MADE CHANGES AT 21Z INSTEAD OF WAITING UNTIL 00Z.
FOR TONIGHT...WE HAD A NICE SUNNY DAY TO DRY THINGS OUT FOR
A CHANGE. OTHER THAN BFD AND JST...WHICH ARE CLOSER TO THE SFC
RIDGE AXIS LATE TONIGHT...HARD TO SEE MUCH FOG AND LOW CIGS
FORMING. IPT MAY HAVE SOME LOWER CIGS LATE...BUT NOT LOOKING AT
MUCH FOG... GIVEN THAT OFTEN THE LOWER CIG GETS GOING FAST...AND
THIS SLOWS FURTHER COOLING. SOME THIN...PATCHY FOG POSSIBLE TOWARD
SUNRISE AT OTHER SITES.
EXPECT VFR CONDITIONS TO RETURN BY MID MORNING ON SUNDAY. SOME
CU AND SC COULD WORK IN ACROSS WESTERN AND SOUTHERN AREAS...BUT
EXPECT CIGS TO BE VFR WHERE THE CLDS ARE BKN. ALSO HELD OFF
MENTION OF SHOWERS PRIOR TO 00Z.
WHILE THIS SOME POTENTIAL FOR SHOWERS FROM LATE SUNDAY INTO
MONDAY...NOT SURE IF MODELS ARE HAVING PROBLEMS WITH TOO MUCH
PHASING OF UPPER LVL ENERGY AND SEVERAL WEAK FRONTS.
STILL THINK BEST CHC OF LOWER CIGS AND SHOWERS WOULD BE SOUTH
OF CENTRAL PA.
OUTLOOK...
SUN NIGHT-MON...BECOMING MVFR CONDITIONS WITH SHOWERS...PERHAPS
IFR AT TIMES.
TUE-THU...MAINLY VFR...ISOLD MVFR CIGS WITH -SHRA STILL POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...FITZGERALD/CERU
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...DANGELO
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1134 PM CDT SAT AUG 18 2012
.AVIATION...
ISOLATED -TSRA HAVE DEVELOPED IN THE VICINITY OF KLBB AT 0430Z AND
THIS ACTIVITY COULD LINGER PAST 0600Z...BUT CONFIDENCE IS LOW.
OTHERWISE...CAN/T TOTALLY RULE OUT A PASSING SHRA/TSRA AT EITHER
TERMINAL THROUGH THE NIGHT...BUT CHANCES ARE WELL TOO LOW TO
MENTION IN TAF. ALSO...SOME LIGHT FOG MAY DEVELOP IN THE VICINITY
OF KLBB BETWEEN 0600 AND 1200Z...AFTER WHICH NORTHERLY WINDS AND
SLIGHTLY DRIER AIR SHOULD SCOUR OUT ANY FOG. VFR CONDITIONS ARE
EXPECTED FOR THE REMAINDER OF SUNDAY WITH AN OUTSIDE CHANCE OF A
THUNDERSTORM.
&&
.PREV DISCUSSION... /ISSUED 1039 PM CDT SAT AUG 18 2012/
UPDATE...
WE/VE TRIMMED POPS BACK FOR THE REMAINDER OF THE NIGHT. ASIDE FROM
THE PERSISTENT SEVERE STORM NOW MOVING ACROSS COCHRAN
COUNTY...ONLY A FEW ISOLD SHOWERS WERE PRESENT ACROSS THE FA. THERE
IS STILL SOME WEAK MID-LVL ENERGY IN THE NW FLOW ALOFT
MAINTAINING SOME SHOWERS IN NE NEW MEXICO...AND THIS ACTIVITY MAY
MAKE IT INTO OUR NW ZONES AFTER MIDNIGHT. OTHERWISE...WEAK ISENTROPIC
LIFT OF THE RELATIVELY MOIST AIRMASS WILL KEEP AN ISOLD
SHOWER/WEAK TSTM POTENTIAL GOING OVERNIGHT ACROSS THE ENTIRE AREA.
PREV DISCUSSION... /ISSUED 638 PM CDT SAT AUG 18 2012/
AVIATION...
VFR CONDITIONS EXPECTED FOR KCDS.
FOR KLBB...AN OUTFLOW BOUNDARY TO THE EAST OF KLBB SHOULD MOVE WEST
ACROSS THE TERMINAL IN THE 00Z TO 02Z TIME FRAME WITH TCU AND
POSSIBLY -TSRA IN THE VICINITY OF KLBB. ADDITIONALLY...THERE IS
A LOW PROBABILITY THAT TSRA ACTIVITY CURRENTLY IN THE TX PANHANDLE
COULD MOVE SOUTH AND IMPACT KLBB SOMEWHERE IN THE 03Z TO 09Z TIME
FRAME. OTHERWISE...SURFACE WINDS WILL TEND MORE TO THE NORTHEAST
AND NORTH AS OUTFLOW BOUNDARIES AND A WEAK COLD FRONT MOVE ACROSS
EARLY SUNDAY MORNING.
PREV DISCUSSION... /ISSUED 551 PM CDT SAT AUG 18 2012/
UPDATE...
QUICK UPDATE TO REMOVE HALL...CHILDRESS AND COTTLE COUNTIES FROM
THE SEVERE THUNDERSTORM WATCH. OVERALL...STORM INTENSITY HAS BEEN
RATHER TAME...THOUGH A FEW CELLS DO OCCASIONALLY PULSE UP. IN
ADDITION...A SMALL CLUSTER OF STORMS COULD GENERATE GUSTY WINDS AS
THEY MOVE THROUGH THE SOUTHEASTERN ZONES OVER THE NEXT HALF HOUR
TO HOUR. UPDATED PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 339 PM CDT SAT AUG 18 2012/
SHORT TERM...
WELL-DEFINED OUTFLOW BOUNDARY/COMPOSITE COLD FRONT WAS MOVING
SOUTHWEST INTO CHILDRESS AND HALL COUNTIES JUST NORTH OF A SURFACE
TROUGH STRETCHING FROM NEAR DIMMITT ESE TO SWEARINGEN. THE TRUE COLD
FRONT OF INTEREST THAT IS PROGGED TO DROP HIGHS BELOW NORMAL ON
SUNDAY /UNDER MOSTLY SUNNY SKIES!/ WAS FOUND DIVING SOUTH ACROSS WRN
KANSAS AND ERN COLORADO. BRUNT OF THE PRECIP POTENTIAL WILL BE
RELEGATED TO THE PRE-FRONTAL BOUNDARIES CURRENTLY CONVECTING ACROSS
THE NRN HALF OF THE CWA. ALTHOUGH WIND SHEAR IS WEAK THUS FAR...THIS
WILL IMPROVE AS THE AFTERNOON AND EARLY EVENING WEAR ON COURTESY OF
A SHORTWAVE TROUGH AND ASSOCIATED WIND MAX APPROACHING IN NORTHWEST
FLOW. EVEN WITH MLCAPES GENERALLY AOB 1000 J/KG...THIS IMPROVING
LIFT SHOULD SECURE A WINDOW FOR ORGANIZED SEVERE STORMS MAINLY IN
THE FORM OF SMALL SEGMENTS OR LINES WITH DMGG WINDS THE GREATEST
THREAT BEFORE INTENSITY AND STORM COVERAGE WANE BY LATE EVENING.
CURRENT SVR WATCH CAPTURES THIS THREAT WELL...BUT MAY REQUIRE
EXPANSION SWWD SHOULD TRENDS WARRANT. A FEW HI-RES MODELS SUCH AS
THE TTU WRF AND HRRR DO INDICATE SUCH A SCENARIO FOR LUBBOCK AND
POINTS SOUTHWEST...SO THIS WILL BE MONITORED CLOSELY BY THE ONCOMING
SHIFT. OTHERWISE...FROPA WILL OCCUR AFTER MIDNIGHT FOLLOWED BY
DIMINISHING POPS. MOIST POST-FRONTAL UPSLOPE TOMORROW AFTN IN ERN NM
AND ADJACENT COUNTIES OF THE TX SOUTH PLAINS STILL APPEARS
REASONABLE FOR SLIGHT CHANCE POPS IN OUR SWRN COUNTIES...HOWEVER THE
NAM LOOKS MUCH TOO BULLISH WITH QPF IN SUCH A REGIME AND IS LARGELY
BEING DISMISSED
LONG TERM...
NNW FLOW ALOFT IS EXPECTED ON MONDAY. HIGH AMPLITUDE RIDGE WILL
SPAN FROM NWRN MEXICO UP TO NORTHERN ALBERTA. OUT EAST...MATURE LOW
WILL BE SITUATED OVER THE SRN PART OF HUDSON BAY WITH AN EMBEDDED
SHORTWAVE DUE INTO THE CENTRAL PLAINS EARLY ON TUESDAY ALTHOUGH THE
BEST ENERGY ASSOCIATED WITH THIS SYSTEM WILL LIKELY REMAIN NORTHEAST
OF THE REGION. BY MID WEEK...THE RIDGE WILL BEGIN TO MOVE EASTWARD
AND FLATTEN WITH SOME HINTS IN BOTH THE GFS AND ECM ABOUT A BIT OF A
DISTURBANCE PASSING TO OUR NORTH ON THURSDAY. WHILE THE ECM
SOLUTION WOULD BE MORE FAVORABLE INTO BRINGING A FRONT INTO THE
REGION...AND PRECIPITATION...THE GFS HAS MORE CLOSELY PARALLELED
REALITY FOR THE PAST WEEK AND THUS WILL TREND THE FORECAST IN THAT
DIRECTION.
GIVEN NWP PERFORMANCE AS OF LATE WRT QPF AM NOT COMPLETELY CONVINCED
THAT WE WILL SEE AS MUCH RAIN ACROSS THE REGION AS PREVIOUSLY
THOUGHT...BUT HAVE ELECTED ONLY TO MAKE A DOWNWARD TREND OF MONDAY
NIGHT POPS. LIKE TODAY...VIRTUALLY EVERY MODEL CONVECTS BUT PRECIP
HAS BEEN HARD TO COME BY. AS PREVIOUSLY MENTIONED...SHORTWAVE
PASSES TO OUR NORTH SOMETIME ON THURSDAY BUT AGAIN...CONFIDENCE IN
MEANINGFUL RAINFALL IS TOO LOW FOR MENTION IN THE WX GRIDS ATTM.
GIVEN THAT...MOST OF THE EXTENDED LOOKS DRY ALTHOUGH WE WOULD LOVE
TO BE WRONG ABOUT THAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 61 83 57 85 58 / 20 10 10 20 30
TULIA 63 83 61 85 60 / 20 10 10 10 30
PLAINVIEW 64 82 61 88 63 / 20 10 10 10 30
LEVELLAND 66 83 61 89 63 / 40 20 10 10 30
LUBBOCK 67 84 62 90 65 / 20 20 10 10 30
DENVER CITY 66 84 62 93 63 / 50 20 10 10 20
BROWNFIELD 66 84 62 93 65 / 50 20 10 10 20
CHILDRESS 68 87 64 91 64 / 20 10 0 10 30
SPUR 68 86 65 94 68 / 20 20 10 10 20
ASPERMONT 70 89 67 97 68 / 20 20 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
808 PM EDT MON AUG 20 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN JUST TO OUR SOUTH THROUGH TUESDAY.
MEANWHILE...A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL PASS
ACROSS OUR REGION FROM THE WEST ON MONDAY AND AGAIN ON TUESDAY.
BY MID WEEK THE FRONT WILL MOVE OFF THE ATLANTIC COAST...ALLOWING
HIGH PRESSURE TO BUILD INTO THE REGION FROM THE WEST AND REDUCING
THE CHANCES FOR SHOWERS AND STORMS.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 800 PM EDT MONDAY...
AS OF 230 PM EDT MONDAY...
SHORTWAVE WILL ROTATE AROUND THE UPPER TROUGH ACROSS OUR REGION THIS
AFTERNOON INTO TONIGHT. THIS WILL RESULT IN SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. SOME OF THE STRONGER STORM MAY CONTAIN GUSTY
WINDS AND HEAVY DOWNPOURS. THE FRONTAL BOUNDARY ACROSS THE SOUTHEAST
U.S. WILL REMAIN TO OUR SOUTH TONIGHT INTO TUESDAY. HRRR AND
WRFARW-RNK LOOKED REASONABLE WITH TIMING AND PLACEMENT OF STORMS.
CONVECTION THIS AFTERNOON WILL SLOWLY DISSIPATE WITH THE LOSS OF
SOLAR HEATING AND PASSAGE OF THE SHORTWAVE. WITH LIGHT WINDS AND LOW
LEVEL MOISTURE ADDED THE MENTION OF FOG TO THE ISC GRIDS TONIGHT
INTO TUESDAY MORNING. LEANED TOWARDS THE ADJMETBC FOR LOW
TEMPERATURES WITH READINGS FROM THE LOWER 50S IN THE MOUNTAINS TO
THE MID 60S IN THE SOUTHEAST.
THE LARGE UPPER LEVEL TROUGH IN THE EAST WILL CONTINUE TUESDAY.
ANOTHER SHORTWAVE WILL DROP SOUTHEAST OUT OF THE OHIO VALLEY ACROSS
OUR REGION. IN THE LOWER LEVELS...WEAK HIGH PRESSURE SITUATED ACROSS
THE LOWER GREAT LAKES SLIDES INTO THE APPALACHIANS...WHILE THE
NEARLY STATIONARY FRONT WILL REMAIN ALONG THE COASTAL SOUTHEAST.
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP TUESDAY AFTERNOON
INTO TUESDAY NIGHT. RAINFALL WILL DIMINISH DURING THE EVENING AS
DAYTIME HEATING ENDS. PLAYED HIGH TEMPERATURES TUESDAY FROM THE
LOWER 70S IN THE MOUNTAINS TO THE LOWER 80S IN THE PIEDMONTS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 PM EDT MONDAY...
RESIDENT UPPER TROUGH IS FORECAST TO FLATTEN MID WEEK WITH RETURN
OF CLOSER TO NORMAL TEMPS. CAN`T RULE OUT ISOLD TO WDLY SCATTERED
POP-UP SHRA/TSRA DURING THE PEAK HEATING HOURS EACH DAY...BUT POPS
PRETTY LOW...20 PERCENT OR LESS...AND FAVORING MAINLY DRY
CONDITIONS. AS THE AIR MASS WARMS AND DRIES...SHOULD SEE A GREATER
DIURNAL TEMPERATURE SPREAD WITH HIGHS IN THE 80S AND LOWS IN THE
50S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 400 PM EDT MONDAY...
WITH FLOW DEAMPLIFIED...NO BIG EXTREMES ANTICIPATED IN THE LONG
TERM. HIGH PRESSURE SHOULD COVER MUCH OF THE ERN CONUS WITH LAZY
LOW LEVEL FLOW. UPPER LEVEL DISTURBANCES WILL BE BURIED WITHIN THE
FLOW...BUT CAN`T ADD ANY GREAT DETAIL TO THE SENSIBLE WEATHER DUE
TO TIMING UNCERTAINTIES. TEMPERATURES SHOULD NOT BE TOO FAR FROM
CLIMO.
AS WE TRANSITION INTO THE WEEK OF AUG 26-31...THE TROPICS WILL
PROBABLY BECOME MORE OF INTEREST. HPC HAS ADDED A TROPIC LOW VCNTY
OF FLORIDA BY DAY 7 PER COORDINATION WITH THE HURRICANE
CENTER...REPRESENTING POSSIBLE TRACK OF AL94.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 800 PM EDT MONDAY...
BAND OF SHOWERS AND ISOLATED THUNDERSTORMS IN THE VIRGINA AND
NORTH CAROLINA FOOTHILLS WILL GRADUALLY DISSIPATE THIS EVENING. DO
NOT EXPECT ANY IMPACT ON ROA/LYH/BLF/LWB/BCB OR DAN TONIGHT.
WITH PARTIAL CLEARING AGAIN TONIGHT PATCHY FOG WITH IFR
CONDITIONS AGAIN POSSIBLE AT LWB ESPECIALLY...BCB AND BLF MORE
LIKELY MVFR OR ONLY VERY BRIEF IFR. ALSO ADDED MVFR FOG TO LYH DUE
TO THE RAIN IN THE AREA THIS AFTERNOON. SURFACE DEW POINTS HAVE
DROPPED IN THE WEST BUT WITH A MOSTLY CLEAR SKY FOG IS EXPECTED
AGAIN OVERNIGHT IN THE WESTERN VALLEYS.
LOCAL WRF SHOWED WEAK EASTERLY WINDS AT THE SURFACE THROUGH 850
MB BY MORNING WITH HIGHER AMOUNTS OF LOW LEVEL MOISTURE EAST OF
THE BLUE RIDGE. STRATUS MAY FORM IN THE LEE OF THE BLUE RIDGE
OVERNIGHT AND MAY BRING IFR CEILINGS INTO LYH AND DAN BUT
CONFIDENCE IS TOO LOW AT THIS TIME TO INCLUDE IN THE TAFS.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE AGAIN ON
TUESDAY AND WEDNESDAY...WITH ISOLATED AND BRIEF MVFR/IFR CONDITIONS.
HIGH PRESSURE WILL THEN BUILD IN FOR THE REMAINDER OF THE
PERIOD...WITH MAINLY VFR/MVFR CONDITIONS EXPECTED AND VERY LITTLE
CHANCE OF SHOWERS OR STORMS DEVELOPING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK
NEAR TERM...AMS/KK
SHORT TERM...PM
LONG TERM...PM
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
246 PM CDT SUN AUG 19 2012
.SHORT TERM...THROUGH TUESDAY NIGHT
246 PM CDT SUN AUG 19 2012
SURFACE ANALYSIS THIS AFTERNOON SHOWS A WEAK COLD FRONT EXTENDING
ACROSS CENTRAL WISCONSIN INTO WESTERN MINNESOTA. HIGH PRESSURE WAS
CENTERED OVER NORTHERN NORTH DAKOTA.
LOCAL AND REGIONAL RADARS ARE SHOWING A FEW SHOWERS DEVELOPING
ALONG AND AHEAD OF THE FRONT ACROSS WISCONSIN INTO EASTERN
MINNESOTA. MU CAPES AROUND A 1000 J/KG ARE IN PLACE AHEAD OF THE
FRONT BUT WITH A WEAK WIND FIELD...THE CONVERGENCE ALONG THE FRONT
IS NOT VERY STRONG. A WEAK SHORT WAVE TROUGH WAS PROVIDING ENOUGH
LIFT TO AID THE DEVELOPMENT OF THE SHOWERS. THIS WAVE WILL SLIP
SOUTH OF THE AREA THIS EVENING TAKING THE FORCING WITH IT. SOME
CONCERN THAT ADDITIONAL WAVES UP STREAM IN THE FLOW ALOFT COULD
CONTINUE TO PROVIDE SOME WEAK FORCING THROUGH THE NIGHT.
HOWEVER...ONCE THE FRONT GOES THROUGH DEW POINTS ARE EXPECTED TO
FALL INTO THE 40S. THIS ALONG WITH THE LOSS OF HEATING...SHOULD BE
SUFFICIENT TO LOWER CAPE AND ALLOW THE SHOWERS TO DISSIPATE. WILL
CARRY A SMALL RAIN CHANCE ACROSS THE SOUTHERN HALF OF THE AREA INTO
THE EVENING TO COVER THE DISSIPATING EVENING SHOWERS.
ONCE THE SHOWERS ARE DONE...THE SKIES SHOULD CLEAR OUT AND WITH
THE HIGH BUILDING IN...THE CONCERN BECOMES WHETHER VALLEY FOG WILL
FORM. ONCE AGAIN...THIS DOES NOT LOOK TO BE A CLEAR CUT EVENT. THE
WINDS AT THE SURFACE ARE EXPECTED TO DECOUPLE AND WITH THE CLEAR
SKIES...GOOD RADIATIONAL COOLING SHOULD OCCUR. HOWEVER...THE
FORECAST SOUNDINGS FROM BOTH THE 19.12Z NAM AND 19.17Z RAP SUGGEST
THE WINDS JUST ABOVE THE SURFACE UP THROUGH AT LEAST 5K FEET
SHOULD BE AROUND 10 KNOTS...BUT DECREASING TOWARD 12Z MONDAY.
ALSO...THE NAM SUGGESTS THAT SATURATION SHOULD ONLY OCCUR AT THE
SURFACE WITH DRIER AIR ABOVE WITH THE STRONGER WINDS. WOULD EXPECT
SOME FOG TO BE AROUND BUT WOULD NOT EXPECT THE WHOLE VALLEY TO
FILL IN AND WILL MAINTAIN THE MENTION OF AREAS OF VALLEY FOG. THE
HIGH WILL THEN DRIFT SOUTHEAST ACROSS THE AREA AND PROVIDE QUIET
WEATHER INTO TUESDAY NIGHT.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
246 PM CDT SUN AUG 19 2012
MODELS IN THIS TIME FRAME HAVE BEEN SHOWING SOME INCONSISTENCIES
ON HOW THE PATTERN WILL EVOLVE AS ENERGY COMES OUT OF THE MEAN
LONG WAVE TROUGH ALONG THE WEST COAST. THE LATEST MODELS RUNS
STILL SHOW A SHORT WAVE TROUGH COMING OUT OF THE WEST COAST SYSTEM
STARTING WEDNESDAY. HOWEVER...NOW INSTEAD OF BUILDING INTO THE
UPPER MIDWEST...THE UPPER LEVEL LOW MOVES NORTHEAST TOWARD CENTRAL
CANADA BRINGING THE SHORT WAVE TROUGH THROUGH THE AREA WITH A
POSITIVE TILT THURSDAY NIGHT THROUGH FRIDAY NIGHT. AS THIS IS
HAPPENING...THE UPPER LEVEL THAT HAD BEEN OFF THE WEST COAST IS
SHOWN TO START MOVING EAST ACROSS SOUTHERN CANADA IMPACTING THE
UPPER MIDWEST OVER THE WEEKEND. AT THE SURFACE...THE 19.12Z GFS
REMAINS STRONGER WITH THE LEAD SYSTEM THAN THE 19.00Z ECMWF
SHOWING A LOW ALONG THE CANADIAN BORDER WITH A COLD FRONT COMING
INTO THE AREA. MEANWHILE...THE ECMWF CONTINUES TO JUST SHOW A WEAK
SURFACE LOW DRIFTING ACROSS THE UPPER MIDWEST. BOTH MODELS THEN
SHOW A LOW MOVING ACROSS CANADA WITH ANOTHER COLD FRONT OVER THE
UPPER MIDWEST WITH THE MAIN UPPER LEVEL LOW...BUT DIFFER ON THE
TIMING WITH THE GFS BEING THE QUICKEST. IN GENERAL...WILL CARRY 30
TO 40 PERCENT RAIN CHANCES STARTING THURSDAY NIGHT THROUGH THE
WEEKEND AND WAIT FOR LATER MODEL RUNS AND HOPEFULLY BETTER
AGREEMENT TO MAKE REFINEMENTS.
&&
.AVIATION...THROUGH 18Z MONDAY
1242 PM CDT SUN AUG 19 2012
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS NORTHEAST
IOWA AND SOUTHWEST WISCONSIN THIS AFTERNOON. A FEW OF THESE MAY
DEVELOP AS FAR NORTH AS THE INTERSTATE 90 CORRIDOR. HOWEVER THE
CONFIDENCE IS NOT HIGH ENOUGH TO BE INCLUDED IN THE TAFS.
FOR TONIGHT...SKIES WILL BE CLEAR ACROSS THE REGION. HOWEVER THE
WINDS JUST ABOVE THE BOUNDARY LAYER REMAINS IN THE 10 TO 15 KNOT
RANGE AND DRIER AIR IS BEING ADVECTED INTO THE REGION. AS A
RESULT...THINKING THAT THERE WILL BE SOME AREAS OF VALLEY FOG JUST
NOT SURE WHETHER IT WILL ACTUALLY AFFECT KLSE. AS A RESULT...KEPT
THE BCFG GOING IN THE TAF. AS FAR KRST...IT LOOKS LIKE THE DRIER
AIR WILL WIN OUT...SO REMOVED THE 4SM BR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
246 PM CDT SUN AUG 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS ALBANY NY
356 AM EDT TUE AUG 21 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PASSING THROUGH THE REGION WILL
ALLOW FOR SOME ISOLATED SHOWERS TODAY AND TOMORROW...MAINLY FOR
AREAS TO THE SOUTH OF THE CAPITAL REGION. HIGH PRESSURE WILL BUILD
INTO THE NORTHEAST TO END THE WEEK...WITH FAIR WEATHER AND
TEMPERATURES MODERATING TO SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 355 AM EDT...A SURFACE BOUNDARY WAS STALLED FROM THE DEEP
SOUTH NORTHEASTWARD TO THE CAROLINA COAST TO OFFSHORE NEW ENGLAND.
ALOFT...A TROUGH WAS CARVED OUT ACROSS THE EASTERN CONUS...WITH
THE POSITIVELY TILTED TROUGH AXIS ACROSS THE OHIO VALLEY. WITH A
130+ KT JET STREAK AT 250 HPA POSITIONED OVER NEW ENGLAND...A
LARGE AMOUNT OF MID AND HIGH LEVEL CLOUDINESS WAS IN PLACE ACROSS
OUR EASTERN ZONES THIS MORNING. AS THE MORNING PROGRESSES...THESE
CLOUDS SHOULD THIN OUT AS THE JET STREAK CONTINUES TO LIFT
NORTHEASTWARD INTO CANADA...ALLOWING FOR A PARTLY TO MOSTLY SUNNY
SKY ACROSS THE AREA FOR TODAY.
THE TROUGH AXIS WILL ONLY SLOWLY BE MOVING EASTWARD. AS A
RESULT...THERE ISN/T MUCH LARGE SCALE LIFT ACROSS OUR AREA
TODAY...AS WE WILL NOT BE IN ANY FAVORABLE QUADS OF THE DEPARTING
JET STREAK EITHER. WITH PWAT VALUES LESS THAN AN INCH AND TD
VALUES ONLY IN THE 40S AND 50S...AND A FORECASTED WEAK CAP AROUND
700 HPA...IT WILL BE DIFFICULT TO SEE MUCH IN THE WAY OF
SHOWERS/TSTORMS TODAY. THE 00 UTC NAM/GFS/UKMET/GGEM/ECMWF ALL
POINT TOWARDS A DRY FORECAST FOR TODAY...WITH MOS POPS RATHER LOW
AS WELL. STILL...WILL GO WITH ISOLD RAIN SHOWERS FOR THE
CATSKILLS...SOUTHERN BERKSHIRES...NW CT...AND ADJACENT AREAS...IN
CASE DIFFERENTIAL HEATING IN THE HIGH TERRAIN CAN POP A
BRIEF...WEAK SHOWER FOR THE AFTN HOURS. THE LATEST 3KM HRRR DOES
SHOW A FEW WEAK ISOLD PULSE SHOWERS OVER THE HIGH TERRAIN
DEVELOPING BY AROUND 18Z.
WITH CAPE VALUES FORECASTED TO ONLY BE A FEW HUNDRED J/KG...LI
VALUES FORECATED TO BE MAINLY ABOVE ZERO AND SUCH SPARSE COVERAGE
OF ACTIVITY...WILL NOT INCLUDE ANY THUNDER AT THIS TIME.
TEMPS TODAY LOOK A TAD WARMER THAN YESTERDAY WITH A BIT MORE
SUNSHINE EXPECTED. VALLEY AREAS LOOK TO SEE UPPER 70S TO LOW
80S...WITH LOWER TO MIDDLE 70S FOR THE HIGH TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
WITH THE LOSS OF DAYTIME HEATING...ANY SHOWERS WILL END BY SUNSET
AND SKIES LOOK NEARLY CLEAR FOR THE OVERNIGHT HOURS. MIN TEMPS
WILL RANGE FROM THE MID 40S TO THE MID 50S.
ON WEDNESDAY...THE TROUGH AXIS WILL BE LIFTING NORTHEASTWARD
ACROSS SOUTHERN PARTS OF OUR AREA. PWAT AND TD VALUES WILL BE A
LITTLE HIGHER FOR WEDNESDAY THAN TUESDAY. DESPITE THE UPPER TROUGH
PASSING TO OUR SOUTH...SFC HIGH PRESSURE CENTERED OVER THE
CAPITAL REGION WILL PROVIDE SUBSIDENCE...AND WITH A WEAK CAP
ALOFT...WE DON/T EXPECT MUCH PRECIP TO DEVELOP. WE WILL ONLY GO WITH
SLIGHT CHC FOR SHOWERS ACROSS THE CATSKILLS FOR THE AFTN HOURS AT
THIS TIME. THE 00 GEFS AGREES WITH THE CATSKILLS HAVING THE BEST
CHANCE OF ANYWHERE OF SEEING SOME MEASUREABLE PRECIP /EVEN IF IT/S
ONLY A FEW HUNDREDTHS OF AN INCH/. AGAIN...INSTABILITY LOOKS
MEAGER...SO NO MENTION OF THUNDER. MAX TEMPS MAY BE A DEGREE OR
TWO WARMER THAN TUESDAY FOR MOST PLACES.
THE UPPER TROUGH WILL LIFT OUT FOR WEDNESDAY NIGHT AND THE FLOW
WILL BECOME ZONAL FOR WED NIGHT INTO THURSDAY. AT THE SURFACE...HIGH
PRESSURE WILL REMAIN IN CONTROL. THIS WILL KEEP IT RAIN FREE
ACROSS THE REGION. IN ADDITION...TEMPS WILL ONCE AGAIN BE A LITTLE
WARMER ON THURSDAY...WITH MID 80S FOR VALLEY AREAS...AND DEWPOINT
VALUES SNEAKING BACK UP TO AROUND 60 F.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A RETURN TOWARD MORE AUGUST-LIKE WEATHER AS HEIGHTS CONTINUE TO RISE
ALONG WITH AN INCREASING MOIST SOUTHERLY FLOW. THERE ARE SOME
SUBTLE HINTS IN THIS MORNINGS MODEL SUITE OF AN EVOLVING CUT OFF
UPPER LOW OVER OR JUST OFFSHORE OF THE MID ATLANTIC REGION. THIS
FORECAST FEATURE IS ALONG THE STALLED OUT FRONTAL BOUNDARY IN THE
VICINITY OF THE GULF STREAM WITH PLACEMENT QUITE DIFFERENT FROM THE
GFS TO THE ECMWF. OUTSIDE OF THIS FEATURE...A WARM FRONT OR THE
LEADING EDGE OF HIGHER THETA-E AIR APPROACHES THIS WEEKEND TOO...
WHICH WE WILL INTRODUCE A SLIGHT CHANCE POPS FOR CONVECTION.
AS 850MB TEMPS REBOUND BACK TOWARD THE MIDDLE TEENS ALONG WITH
DEWPOINTS BACK TOWARD AND EVENTUALLY ABOVE 60F...SURFACE
TEMPERATURES WILL REBOUND BACK INTO THE 80S FOR MANY VALLEY
LOCATIONS WITH OVERNIGHT LOWS SLOWLY CLIMBING BACK INTO THE LOWER
60S.
LOOKING FURTHER AHEAD INTO THE START OF NEXT WEEK...MODELS DIVERGE
SIGNIFICANTLY AS THE GFS REMAINS THE MOST PROGRESSIVE WITH A FRONT
APPROACHING WHILE THE ECMWF IS MORE PRONOUNCED AND SLOWER WITH THE
POTENTIAL FRONT. MEANWHILE...WE WILL BE WATCHING THE TROPICS WITH
GREAT INTEREST WITH THE APPROACH OF A SOON TO BE NAMED SYSTEM ACROSS
THE CENTRAL TROPICAL ATLANTIC...PLEASE REFER TO THE LATEST FORECAST
GUIDANCE FROM THE NATIONAL HURRICANE CENTER.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
CHALLENGING FORECAST THE NEXT 6-9 HRS AS IT WILL BE RACE BETWEEN
COLLAPSING DEWPOINT DEPRESSIONS AND THE DEPARTURE OF THE BKN-OVC MID
LEVEL CLOUD DECK. WHERE ENOUGH BREAKS IN THE CLOUDS DO
OCCUR...THERE IS A HIGH POTENTIAL FOR IFR TO LIFR CONDITIONS TO
DEVELOP WITH FOG AND LOW CIGS. AT THE PRESENT TIME...WE FEEL KGFL
STANDS THE BEST CHANCE FOR THOSE LOWER THRESHOLDS AND WE FORECAST
THOSE CONDITIONS TO BE MET. ELSEWHERE...WHERE RAIN WAS MORE OF AN
IMPACT...EXPECTATIONS ARE FOR AT LEAST MVFR CONDITIONS DUE TO
MIST/BR WITH THE CHANCE FOR IFR CONDITIONS AS WE WILL PLACE TEMPO
GROUPS FOR THIS POTENTIAL.
ONCE SUNSHINE OCCURS...ANY FOG OR LOW STRATUS WILL QUICKLY DISSIPATE
AND FLIGHT CONDITIONS RETURN BACK TO VFR.
WINDS WILL BE RATHER LIGHT...LESS THAN 10 KTS...THROUGH THE FORECAST
PERIOD.
OUTLOOK...
WED-SAT...MAINLY VFR CONDITIONS. CHC FOR LATE NT/EARLY AM BR/FOG.
&&
.FIRE WEATHER...
AN UPPER LEVEL TROUGH WILL SLOWLY MOVE EAST FROM THE OHIO VALLEY...
AND BRING SOME ISOLATED RAIN SHOWERS OVER SOUTHERN PARTS OF THE
AREA FOR TODAY AND TOMORROW...ALTHOUGH MOST AREAS WILL BE DRY FOR
MUCH OF THE TIME...AND RAINFALL AMOUNTS WILL BE LIGHT. HIGH PRESSURE
WILL RETURN TO THE REGION BY THURSDAY WITH SEASONABLE
TEMPERATURES.
RH VALUES WILL DROP TO 30-40 PERCENT THIS AFTERNOON. RH VALUES
WILL RECOVER TO NEAR 100 PERCENT TONIGHT...AND DROP TO BETWEEN
30-40 PERCENT WEDNESDAY AFTERNOON.
OVER THE NEXT FEW DAYS...SURFACE WINDS WILL BE LIGHT AND VARIABLE.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS.
ISOLATED RAIN SHOWERS ARE POSSIBLE OVER THE CATSKILLS TODAY AND
TOMORROW. A FEW OF THESE SHOWERS MAY DRIFT INTO THE MID HUDSON
VALLEY...BERKSHIRES...TACONICS...AND NW CT. WITH PWAT VALUES RATHER LOW
/GENERALLY LESS THAN 1.00 INCH/...RAINFALL WILL NOT BE VERY
INTENSE...AND ANY RAINFALL AMOUNTS WILL BE LIGHT. AS A
RESULT...THIS RAIN WILL HAVE LITTLE TO NO EFFECT ON AREA RIVERS AND
STREAMS.
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...BGM
AVIATION...BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1229 AM CDT TUE AUG 21 2012
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1215 AM CDT TUE AUG 21 2012
AT 00Z TUESDAY A 250MB JET STREAK EXTENDED FROM WYOMING TO
NORTHERN CALIFORNIA. THIS JET STREAK WAS ROTATING AROUND A 500MB
RIDGE AXIS THAT WAS LOCATED FROM UTAH TO IDAHO. ANOTHER UPPER
LEVEL JET STREAK APPEARS TO BE LOCATED EAST OF THIS UPPER LEVEL
RIDGE AXIS ACROSS EASTERN COLORADO. 500MB MOISTURE THIS MORNING STRETCHED
FROM THE UPPER LEVEL RIDGE AXIS EASTWARD INTO THE WESTERN HIGH
PLAINS. THE BETTER 700MB MOISTURE APPEARS TO BE LOCATED FROM DODGE
CITY TO AMARILLO TO NEAR ALBUQUERQUE. 05Z SATELLITE LOOP EVEN
INDICATED SOME CLEARING SKIES DEVELOPING ACROSS PARTS OF NORTHEAST
COLORADO AND NORTHWEST KANSAS. A WEDGE OF HIGHER DEWPOINTS AT THE
850MB LEVEL EXTENDED FROM SOUTHEAST COLORADO INTO THE PANHANDLE
OF TEXAS WHICH WAS ALSO WHERE THE 850MB BAROCLINIC ZONE WAS
LOCATED AND WHERE SOME WIND CONFLUENCE WAS EVIDENT EARLY THIS
MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 222 PM CDT MON AUG 20 2012
TONIGHT:
THE IMMEDIATE SHORT TERM FORECAST IS WHAT TO DO WITH POPS THIS EVENING.
NORTHWEST FLOW ALOFT AND OROGRAPHICALLY INDUCED CONVECTION ACROSS COLORADO WILL
CREATE A CLASSIC MCS LATE SUMMER TIME EVENT FOR FAR SW KANSAS. RIGHT
NOW THE MESOSCALE MODELS (NAM, WRF) SHOWS THAT THE BEST 310K ISENTROPIC
LIFT AND WARM AIR (THETA-E) ADVECTION WILL BE LOCATED ACROSS THE SOUTHWESTERN
COUNTIES. THIS AREA IS ALSO CLOSER TO AN APPROACHING 80 KT 250 HPA JET
STREAK MOVING ACROSS THE REGION TONIGHT. THE MOST RECENT HRRR IS QUITE
AGGRESSIVE WITH COMPOSITE REFLECTIVITIES AND ASSOCIATED PRECIPITATION
TOWARDS 05Z (MIDNIGHT) FOR THE CENTRAL COUNTIES. FOR NOW, WILL HOLD
OFF ON THIS SOLUTION SINCE THIS MODEL MIGHT BE OVERDOING THE RESULTANT
COLD POOL FROM THE CONVECTIVE SCHEME. HAVE DOUBTS FOR SEVERE WEATHER
AS DEWPOINTS ARE MAINLY IN THE 40S DEG F. THERE ARE SOME HIGHER DEWPOINTS
(LOWER 50S DEG F) ACROSS THE PANHANDLES, BUT THIS BETTER MOISTURE SHOULD
STAY SOUTH OF THE REGION. KINEMATIC PROFILES SUGGEST THE POSSIBILITY
OF SEVERE WEATHER WITH 0-6 KM BULK SHEAR FORECAST TO BE ABOUT 45 KT
AND ANVIL LEVEL STORM RELATIVE WINDS AROUND 80 KT. THE FLY IN THE OINTMENT
FOR THIS EVENING IS MEAGER CAPE ASSOCIATED WITH MARGINAL BOUNDARY
LAYER DEWPOINTS. 700-500 HPA LAPSE RATES AROUND 7.5 C/KM AND 500-300
HPA LAPSE RATES AROUND 6.7 C/KM IN COMBINATION WITH 500 J/KG OF
SBCAPE SUGGEST MARGINAL HAIL FOR ANY SUSTAINED UPDRAFT - MAINLY
TOWARDS ELKHART.
TOMORROW:
KEPT THE IDEA OF LOWER TEMPERATURES ACROSS THE SW COUNTIES AS TEMPERATURES
SHOULD BE MODERATED BY THE ANTICIPATED RAINFALL ACROSS THE REGION. I
HAVE LOWER 80S DEG F FOR THE SOUTHWEST COUNTIES AND MID TO UPPER 80S
DEG F ELSEWHERE. THINK THE 12Z NAM IS OVERDOING TEMPS ACROSS THIS REGION.
MAX CLIMO FOR THE REGION IS AROUND 88 DEG F FOR TOMORROW. THE 12Z NAM
IS SUGGESTING THE POSSIBILITY FOR CONVECTION ACROSS FAR WESTERN KANSAS
ALONG THE LEE SURFACE TROUGH FOR TOMORROW EVENING. WILL PUT SLIGHT POPS
IN THE GRIDS FOR NOW. NOT TOTALLY CONFIDENT AS UPPER LEVEL DYNAMICS
ARE FORECAST TO BE ON THE WEAKER SIDE TOMORROW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 246 PM CDT MON AUG 20 2012
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING, WILL PHASE OUT 20 PERCENT
SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS FROM OUR WESTERN
FORECAST POINTS NEAR SYRACUSE AND ELKHART BY 06Z. THE TROUGH THE
AFTERNOON CONVECTION WILL TRIGGER ON LATE TUESDAY WILL SLOWLY
DISSIPATED DURING THE EARLY OVERNIGHT PERIOD TUESDAY NIGHT.
ANOTHER SHORT WAVE WILL COME THROUGH THE NORTHWEST FLOW ALOFT LATE
WEDNESDAY AND GENERATE ANOTHER LOW PRESSURE TROUGH NEAR OUR WESTERN
BORDER. LOW 20 POPS FOR ELEVATED THUNDERSTORMS WILL RESULT AFTER
21Z WEDNESDAY, AND SPREAD EASTWARD DURING THE EVENING WEDNESDAY.
THE SURROUND OFFICES SEEMED TO FAVOR 30 PERCENT CHANCE POPS WED, SO
I STUCK WITH 30 POPS FOR ALL AREAS EXCEPT 40 PERCENT POPS IN IN OUR
EASTERN 2 TIERS OF COUNTIES, EAST OF A LINE FROM LARNED TO COLDWATER
WED NIGHT. MOST OF THESE THUNDERSTORMS WILL LIKELY BE ELEVATED AND
ONLY PRODUCE RAINFALL IN THE 0.10 RANGE IN OUR SOUTHEAST ZONES, BUT
SOMEWHAT LOWER AND ONLY IN THE 0.02 TO 0.06-INCH RANGE UP NORTH AND
TO THE WEST. THOSE UPPER WAVES ARE JUST STACKED ONE AFTER ANOTHER,
SO PRECIP CHANCES IN THE 20 TO 30 PERCENT RANGE WILL CONTINUE INTO
THURSDAY, BUT INCREASE IN THE 40 PERCENT RANGE ACROSS OUR EASTERN
1/3RD OF THE CWA, BASICALLY EAST OF A WAKEENEY TO KINSLEY TO MEADE
LINE. A STEADY SOUTHERLY FLOW WILL BRING MID 60S DEW POINTS INTO
THAT AREA THURSDAY AFTERNOON, AND A SYNOPTIC SCALE UPPER WAVE WILL
CROSS JUST NORTH OF OUR CWA THURSDAY NIGHT.
FRIDAY SHOULD SEE A LITTLE RELAXING/WEAKENING OF THE STRENGTH OF
THE PASSING UPPER WAVE, WITH ONLY OUR SOUTHEAST ZONES NEAR MEDICINE
LODGE CARRYING 30 POPS. AS A WARM FRONT NUDGES NORTH FRIDAY NIGHT
AND STEADY UPPER SCALE LIFT STAYS OVER WESTERN KANSAS, MUCH OF THE
CWA COULD SEE HIGH BASED SHOWERS AND ISOLATED STORMS FRIDAY NIGHT.
A CHANCE CATEGORY 30 PERCENT POPS WILL COVER MUCH OF THE EASTERN
HALF OF THE FORECAST AREA, WHILE 20 POPS WILL BE OVER THE SOUTHWEST
ZONES FRI NT. SATURDAY, SATURDAY NIGHT AND SUNDAY ALL LOOK GOOD FOR
30 TO 40 PERCENT RAIN CHANCES IN OUR EASTERN HALF OF THE CWA, WITH
EVEN OUR SOUTHWEST COUNTIES HAVING A 20 PERCENT CHANCE SATURDAY
NIGHT. SUNDAY WAS SOMEWHAT QUESTIONABLE AS TO WHERE THE UPPER WAVE
WILL BE, BUT OUR EASTERN-MOST ZONES FROM HAYS TO PRATT TO MEDICINE
LODGE WILL STILL HAVE 20 POPS. BY SUNDAY, THE LAST IN A SERIES OF
UPPER WAVES COULD BE FAR ENOUGH EAST TO LEAVE POPS OUT OF OUR EAST
ZONES ALL TOGETHER SUNDAY. WILL HAVE TO SEE THE NEXT MODEL RUN TO
DETERMINE IF PRECIP CHANCES ARE WARRANTED SUNDAY.
AS FOR TEMPERATURES, I ACCEPTED WHAT THE CREXTENDFCST_INIT PROCEDURE
GAVE ME. BASICALLY, FOR WEDNESDAY THROUGH SUNDAY, HIGH TEMPERATURES
WILL BE IN THE MID TO UPPER 80S ACROSS OUR NORTHERN HALF OF THE CWA,
AND FROM THE UPPER 80S TO LOWER 90S IN OUR SOUTHERN HALF. MINIMUM
TEMPERATURES WILL START OUT IN THE LOWER 60S WEDNESDAY, AND WARM TO
THE MID 60S TO LOWER 70S (SE) FRIDAY THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1215 AM CDT TUE AUG 21 2012
MOISTURE IN THE 850-700MB LEVEL WILL BE PRESENT THROUGH AT LEAST
LATE MORNING AT DDC AND GCK AS WEAK WARM AIR ADVECTION DEVELOPS
ACROSS SOUTHWEST KANSAS. THIS SHOULD RESULT IN A PERIOD OF VFR
CIGS BETWEEN THE 7000 AND 10000 FEET EARLY TODAY. SOUTHERLY WINDS ARE
EXPECTED TO CONTINUE AND WILL INCREASE INTO THE 10 TO 15 KNOT
RANGE BY LATE DAY AS SURFACE PRESSURES BEGIN TO FALL ALONG THE LEE
OF THE ROCKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 86 64 86 / 10 20 30 20
GCK 61 88 64 88 / 20 20 30 20
EHA 62 88 65 87 / 20 20 20 20
LBL 62 88 66 87 / 20 20 30 20
HYS 61 90 65 87 / 10 20 30 30
P28 62 89 66 86 / 10 20 40 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
431 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A WEAK COLD FRONTAL WILL CROSS THE STATE TODAY INTO TONIGHT WITH
SOME SHOWERS POSSIBLE. ANOTHER WEAK DISTURBANCE WILL MOVE ACROSS THE
REGION ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MAIN CHALLENGE THIS TERM WILL BE SHOWER ACTIVITY AND QPF.
LATEST RADAR SHOWED ACTIVITY MOVING INTO WNW MAINE THIS MORNING W/ECHOES
UP TO 30DBZ WHICH LEADS TO THE POTENTIAL FOR SOME SHOWER ACTIVITY
TO REACH THE GROUND. SATL IMAGERY & CEILING PLOTS INDICATED CLOUD
DECKS OF 7K-10K FT. THIS IS REFLECTED IN THE UPPER AIR ANALYSIS.
THE LATEST NAM AND GFS HAVE INITIALIZED WELL W/THE LATEST RADAR
IMAGERY. HRRR INITIALIZED WELL BUT SEEMS TO BE OVERDONE W/ITS
RAINFALL OVERSPREADING THE CWA BY LATE MORNING INTO THE AFTERNOON.
MID LEVEL FORCING ALONG W/LLVL CONVERGENCE ALONG AND JUST AHEAD OF
THE FRONTAL BOUNDARY WILL ALLOW FOR SHOWERS TODAY. ATTM, USED A
BLEND OF THE NAM12 AND GFS FOR THE POPS WHICH SHOW 20-40% ACROSS
THE CWA EXCEPT THE COAST. HPC QPF LOOKS OVERDONE AND TOO FAR
SOUTH. THEREFORE, DECIDED TO BLEND THE NAM12/HPC AND SREF FOR QPF
WHICH SHOWS NO MORE THAN .10 OF AN INCH AND THIS WILL BE MAINLY
ACROSS THE CENTRAL AND EASTERN AREAS. STAYED CLOSE W/THE DAYCREW`S
MAXES FOR TODAY W/MID 70S NORTH AND UPPER 70S TO AROUND 80 FOR THE
CENTRAL AND DOWNEAST AREAS. ANOTHER FACTOR TODAY WILL BE WINDS AND
MDL SOUNDINGS INDICATE AN INVERTED V-SOUNDING WHICH SUPPORTS SOME
WIND TO POSSIBLY MIX DOWN. DECIDED TO BOOST WIND GUSTS TO 20 MPH
MAINLY ACROSS THE HIGHER TERRAIN AND OPEN AREAS.
TONIGHT WILL SEE CLOUDS BEGINNING TO BREAK UP AS THE FRONT SLOWLY
SLIDES TO THE EAST. SOME CAA IS SEEN BEHIND THE FRONT AND W/WINDS
BECOMING LIGHT AND A WET GROUND, THINKING HERE IS THAT SOME FOG
WILL FORM. BUFKIT PROFILES SUPPORT THIS THINKING. MID LEVEL MOISTURE
IS SHOWN BY THE GFS AND NAM TO MOVE ACROSS NORTHERN AREAS OVERNIGHT.
THIS COULD HALT FURTHER PROGRESSION OF THE FOG. ADDED FOG TO THE
FORECAST BUT NOT CONFIDENT TO GO ANY MORE THAN USING PATCHY
WORDING. DAYCREW CAN ASSESS THIS FURTHER. TEMPERATURES WILL BE
COOL W/MINS DROPPING BACK INTO THE MID AND UPPER 40S ACROSS THE
NORTH AND WEST AND LOW TO MID 50S FOR THE CENTRAL AND DOWNEAST REGIONS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN TO OUR SOUTH ON WEDNESDAY AS LOW
PRESSURE MOVES EAST ACROSS ONTARIO/QUEBEC PROVINCE. THIS WILL KEEP
A SOUTHWEST FLOW AND WEAK WARM ADVECTION ACROSS THE REGION ON
WEDNESDAY WITH PARTLY/MOSTLY SUNNY SKIES. HIGHS ON WEDNESDAY WILL
RANGE FROM THE LOW/MID 70S NORTH AND UPPER 70S TO NEAR 80
DOWNEAST. A DRY NIGHT CAN BE EXPECTED WEDNESDAY NIGHT AS LOW
PRESSURE CONTINUES TO SLIDE TO OUR NORTH. LOWS WEDNESDAY NIGHT
WILL RANGE FROM THE LOW TO MID 50S. A COLD FRONT WILL SLIDE ACROSS
THE REGION ON THURSDAY. SB CAPES ARE UNIMPRESSIVE SO WILL NOT
INCLUDE THE MENTION OF THUNDER BUT WILL MENTION THE CHANCE FOR
AFTERNOON SHOWERS MAINLY ACROSS NORTHERN AND CENTRAL AREAS. HIGH
ON THURSDAY WILL RANGE FROM THE MID TO UPPER 70S NORTH AND LOW TO
MID 80S DOWNEAST...BUT IT WILL BE COOLER NEAR THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THURSDAY NIGHT AND
FRIDAY. THIS WILL BRING MAINLY CLEAR SKIES TO THE REGION THURSDAY
NIGHT AND MOSTLY SUNNY SKIES ON FRIDAY. HIGH PRESSURE WILL SLIDE
EAST ON SATURDAY AND SUNDAY WITH CONTINUED DRY WEATHER. A FRONT WILL
APPROACH FROM THE WEST SUNDAY NIGHT WITH INCREASING CLOUDS. THE FRONT
WILL SLIDE EAST ACROSS THE REGION MONDAY WITH THE CHANCE FRO
SHOWERS.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: STAYED CLOSE TO VFR INTO TONIGHT. SOME PATCHY FOG COULD
ALLOW FOR BRIEF MVFR/IFR CONDITIONS AT THE AIRFIELDS EARLY
WEDNESDAY MORNING. FOG SHOULD LIFT AND BURN OFF BY 8 AM.
SHORT TERM: MAINLY VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM: NO HEADLINES. SSE SWELL WILL CONTINUE THROUGH THE
PERIOD W/WAVE HEIGHTS OF 2-3 FT AND THIS WILL MAINLY BE AWAY FROM
THE INTRA-COASTAL WATERS. WINDS WILL LIGHT AVERAGING 5-10 KTS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SCA LEVELS THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
456 AM EDT TUE AUG 21 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EDT TUE AUG 21 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THAT THE DEEP TROF THAT
HAS DOMINATED THE ERN CONUS FOR SEVERAL DAYS IS IN THE PROCESS OF
DEAMPLIFYING AND LIFTING OUT. SHORTWAVE THAT DROPPED THRU THE UPPER
LAKES YESTERDAY AND GENERATED SCT SHRA IS HEADING FOR THE UPPER OHIO
VALLEY. TO THE N...A SHORTWAVE IS MOVING SE THRU NRN MANITOBA TOWARD
NRN ONTARIO. IN RESPONSE...ZONE OF WAA IS SPREADING E ACROSS NRN
ONTARIO EARLY THIS MORNING. SOME CI IS PEELING S TOWARD THE UPPER
LAKES...BUT WAA MID CLOUDS AND ANY SHRA ARE STILL WELL N OF THE FCST
AREA. MAINLY CLEAR SKIES ACROSS THE FCST AREA AND LITTLE/NO WIND
COMBINED WITH THE MOISTURE FROM YESTERDAYS SHRA HAS LED TO RECENT
DEVELOPMENT OF SHALLOW PATCHY FOG AS A NUMBER OF OBS ARE SHOWING
WIDELY FLUCTUATING VIS.
MAIN FCST CONCERN IN THE SHORT TERM IS POTENTIAL OF CONVECTION
TONIGHT AS TRAILING SFC COLD FRONT FROM AFOREMENTIONED SHORTWAVE
SAGS S TOWARD THE UPPER LAKES. TODAY WILL BE A DRY DAY AS MAIN PUSH
OF WAA CONTINUES TO BE EASTWARD ACROSS NRN ONTARIO AHEAD OF
SHORTWAVE DROPPING SE INTO NRN ONTARIO. UNDER MOSTLY SUNNY
SKIES...MIXING UPWARDS OF 800MB OR SO ON FCST SOUNDINGS YIELDS MAX
TEMPS MAINLY IN THE MID/UPPER 70S. SOME LOCAL COOLING WILL OCCUR
NEAR THE GREAT LAKES.
TONIGHT...850MB THERMAL RIDGE AND MAIN ZONE OF WAA SINKS S INTO THE
UPPER LAKES. AXIS OF MODEST WRLY LOW-LEVEL JET OF 20-30KT REMAINS
MOSTLY JUST N OF UPPER MI...BUT PROXIMITY IS PROBABLY CLOSE ENOUGH
TO WARRANT A SLIGHT CHC OF SHRA/TSRA OVER THE KEWEENAW LATE TONIGHT.
CHC POPS WERE UTILIZED TO THE N ACROSS LAKE SUPERIOR. PER FCST
SOUNDINGS...LOW-LEVELS REMAIN DRY WITH MOISTURE CONFINED TO ROUGHLY
ABOVE 750MB. MIGHT BE ABLE TO GET 100-200J/KG OF CAPE FOR PARCELS
LIFTED FROM THE ELEVATED MOIST LAYER. GIVEN THE LACK OF
INSTABILITY...THE ELEVATED CONVECTION MAY HAVE TROUBLE PRODUCING
PCPN THAT WILL REACH THE GROUND. WITH S/SW WINDS STIRRING IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...TEMPS THERE MAY NOT FALL BLO
60F TONIGHT. EXPECT 50S ELSEWHERE. SHOULD BE ENOUGH DECOUPLING FOR
MINS DOWN TO AROUND 50F IN THE TRADITIONAL COLD SPOTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 450 AM EDT TUE AUG 21 2012
LARGE SCALE PATTERN FEATURES TROUGH OVER GREAT LAKES CONTINUING TO
BREAK DOWN INTO MORE ZONAL FLOW PATTERN BY LATE THIS WEEK. THIS
ALLOWS SHORTWAVE TROUGH EMERGING FROM TROUGH AXIS FROM GULF OF
ALASKA TO PACIFIC NORTHWEST TO PROPEL EAST INTO NORTHERN PLAINS
AND UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. AHEAD OF THE NORTHERN
PLAINS SHORTWAVE...SURFACE TROUGH OVER NORTHERN ONTARIO WILL DROP
INTO UPPER GREAT LAKES ON WEDNESDAY AND BECOME FAIRLY STATIONARY OVER
UPPER MICHIGAN THROUGH FRIDAY. COULD SEE AT LEAST A COUPLE INTERVALS
OF SHRA/TSRA THURSDAY INTO FRIDAY AS THE LARGER SCALE UPPER TROUGH
INTERACTS WITH THE SURFACE TROUGH.
MAJORITY OF MOISTURE ALONG AND AHEAD OF SURFACE TROUGH ON WEDNESDAY
IS H7-H5 WITH LIFT ACTING ON THIS LAYER OF MOISTURE. VERY LITTLE
MOISTURE IS PRESENT BLO H7...SO FOR WEDNESDAY HAVE KEPT POPS TIED
INTO THE AREA OF H7-H5 MOISTURE/UVM AND H7 MOISTURE ADVECTION.
STRONGEST PVA FM SHORTWAVE TRACKING ACROSS ONTARIO STAYS WELL TO THE
NORTH AND EAST OF UPR MICHIGAN...AS DOES DIVERGENCE ALOFT FM JET
STREAK PASSING JUST SOUTH OF JAMES BAY. OVERALL THERE IS NOT A LOT OF
FORCING TO JUSTIFY POPS OVER MOST OF CWA. KEPT SOME POPS IN THE EAST
CWA...BUT REMOVED POPS OVER THE CENTRAL CWA. GIVEN EXPECTED THINNING
MID CLOUDS BY AFTERNOON SHOULD SEE TEMPS WARM NICELY WITH STRONGER
1000-850MB SW WINDS PRESENT JUST AHEAD OF BOUNDARY DROPPING INTO
UPPER GREAT LAKES. NAM/GFS SOUNDINGS POINT TO MIXING UP TO 850-800MB.
MIXING TO H85 YIELDS RETURN TO THE 80S FOR MUCH OF THE AREA...BOOSTED
FURTHER BY MINIMAL LAKE BREEZES AS STRONGER 950-925MB SW WINDS HOLD
THROUGH THE AFTN. WITH ENOUGH SUNSHINE...IT IS LIKELY THAT SOME
AREAS OF CWA SEE TEMPS INTO THE MIDDLE 80S. MINIMUM IN PRECIP CHANCE
CONTINUES THROUGH MOST OF WEDNESDAY NIGHT AND MAYBE INTO THURSDAY
MORNING AS WELL AS MAIN FOCUS FOR SHRA/TSRA WILL BE TIED INTO LEAD
SHORTWAVE PUSHING INTO MINNESOTA BY 12Z THURSDAY OUT AHEAD OF H85-H5
TROUGH MOVING ACROSS THE NORTHERN PLAINS.
CHANCES FOR SHRA/TSRA INCREASE BY THURSDAY AFTERNOON AS THE LEAD
SHORTWAVE PRESSES INTO UPPER GREAT LAKES AND INTERACTS WITH
TEMPERATURE AND MOISTURE ADVECTION INTO SURFACE BOUNDARY PRESENT
OVER THE AREA. MAX H85 MOSITURE ADVECTION AND PVA FROM THE WAVE
COINCIDE OVER WEST HALF OF UPR MICHIGAN ON THURSDAY. INCREASED POPS
OVER THE WEST BUT ALSO WENT WITH SLIGHT CHANCE FOR ALL AREAS DUE TO
THE LOW-LEVEL TROUGH IN THE VICINITY. SHOWED WARMEST TEMPS ON
THURSDAY OVER THE EAST AS THERE IS HIGHER PROBABILITY IT REMAINS
MOSTLY SUNNY THERE INTO THE EARLY-MID AFTERNOON. TEMPS WILL RANGE
FROM THE MID 70S AT THE COOLEST AND WITH ENOUGH SUNSHINE MAY BUMP
INTO THE MID 80S OVER THE EAST. SEEMS THAT BETTER CHANCES OF
SHRA/TSRA THURSDAY NIGHT SET UP MORE OVR LK SUPERIOR ON NOSE OF H85
JET AND CLOSER TO TRACK OF LEAD SHORTWAVE LIFTING INTO ONTARIO.
CANNOT RULE OUT CHANCES ANYWHERE THOUGH AS AGAIN...THE SURFACE FRONT
IS STILL FORECAST CLOSE TO UPR MICHIGAN. INTO FRIDAY...BEFORE IT
LOOKED LIKE THIS WOULD BE THE DAY OF GREATEST RAIN CHANCES. NOT SO
CLEAR CUT NOW THOUGH...AND UNFORTUNATELY THIS FORECAST UNCERTAINTY
PERSISTS RIGHT THROUGH THE UPCOMING WEEKEND AS WELL. STILL PREFER TO
HOLD ONTO THE IDEA FM THE ECMWF AND GEM-NHEM WITH ANOTHER BOUT OF
H85 MOISTURE ADVECTION KICKING OFF SHRA/TSRA ALONG H5 TROUGH AXIS
OVR UPR MICHIGAN DURING PEAK HEATING. STRONGEST HEIGHT FALLS THEN
SHIFT TO THE NORTH AND EAST OF CWA FRIDAY NIGHT SO EXPECT GREATEST
RAIN CHANCES TO PROBABLY DO SO AS WELL.
CURRENT FORECAST FOR SATURDAY AND SUNDAY FEATURES CHANCES FOR
SHRA/TSRA BUT MODEL TRENDS NOW SUGGEST IT MAY END UP BEING MOSTLY
FREE OF RAIN...AT LEAST SATURDAY AND SATURDAY NIGHT. ONLY MODEL THAT
HITS POPS UP THIS WEEKEND IS THE GFS...BUT SINCE GFS SOLUTION
CONTINUES TO BE INFLUENCED BY CONVECTIVE FEEDBACK...HPC HAS TOSSED
IT OUT FOR THIS FORECAST CYCLE. BASED ON POSITION OF INCOMING UPPER
TROUGH OVR SCNTRL CANADA...UPPER JET...SFC FRONT AND H85-H7 MOISTURE
ADVECTION...BETTER SHRA/TSRA CHANCES WOULD SEEM TO SPLIT MORE AROUND
UPR MICHIGAN THROUGH THE WEEKEND. LATER FORECASTS MAY NEED TO TREND
DRIER. LACK OF CLOUDS/SHRA/TSRA WOULD LEAD TO WARMER TEMPS AS WELL
SINCE H85 TEMPS ARE A WARM 15-18C AND LOW-LEVEL WINDS ARE SOUTHWEST
AHEAD OF LARGER SCALE TROUGH. CURRENT FORECAST POINTS TO UPPER
70S-LOWER 80S WITH MOSTLY CLOUDY SKIES AND A CHANCE FOR RAIN. WHEN
IN REALITY IT VERY WELL COULD END UP MOSTLY SUNNY WITH HIGHS IN THE
MID-UPPER 80S. BY LATE SUNDAY...BETTER CHANCES OF SHRA/TSRA PRESS
ACROSS CWA WITH COLD FRONT TIED TO UPPER TROUGH MOVING FM MANITOBA
INTO ONTARIO. EXACT TIMING WITH THIS FRONT WILL REMAIN A QUESTION
UNTIL WE GET CLOSER TO THE WEEKEND THOUGH...SO KEPT WITH CONSENSUS
APPROACH FOR POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 137 AM EDT TUE AUG 21 2012
EXPECT VFR CONDITIONS THROUGH THE FCST PERIOD WITH RELATIVELY DRY
LOW LEVELS AS HIGH PRES BUILDS INTO THE REGION. WEAK WRLY DOWNSLOPE
FLOW AT KSAW WILL MINIMIZE ANY POTENTIAL FOR FOG FORMATION AFTER SOME
MOISTENING WITH RAIN SHOWERS THAT OCCURRED MON AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EDT TUE AUG 21 2012
LIGHTER WINDS BECOMING WEST SOUTHWEST AND INCREASE TO 15-25 KTS
LATER TODAY INTO TONIGHT AS FRONT DROPPING IN FROM ONTARIO TIGHTENS
PRESSURE GRADIENT. STRONGEST WINDS WILL OCCUR OVER WEST AND NORTH
CENTRAL LK SUPERIOR BETWEEN ISLE ROYALE AND TIP OF KEWEENAW. WINDS
RELAX ON WEDNESDAY AS PRESSURE GRADIENT SLACKENS. EXPECT WINDS TO
INCREASE AGAIN FOR THE UPCOMING WEEKEND AS STRONGER LOW PRESSURE
SYSTEM AND FRONT APPROACH FROM THE PLAINS. COULD SEE SOUTHERLY
GUSTS TO 25 KTS OVER EASTERN SECTIONS SATURDAY NIGHT INTO SUNDAY
JUST AHEAD OF THE FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
130 AM EDT TUE AUG 21 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH PARKED OVER THE MISSISSIPPI VALLEY WILL
CONTINUE TO BRING COOLER AND MORE UNSETTLED WEATHER TO THE AREA
THROUGH THE END OF THE WEAK BEFORE HIGHER PRESSURE MOVES IN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 950 PM MONDAY...
DEEP L/W TROUGH ALOFT CONTINUES TO ALLOW MID/UPPER MOISTURE TO
STREAM INTO THE AREA THIS EVENING... RESULTING IN MOSTLY CLOUDY TO
OVERCAST SKIES. AT THE SURFACE A WEAK SURFACE FRONT/TROUGH CONTINUES
TO LINGER ACROSS COASTAL PORTIONS OF NC EXTENDING SOUTHWESTWARD INTO
THE GULF COAST STATES... WITH A MORE SIGNIFICANT AIR MASS CHANGE
ACROSS THE REGION (AT OUR LATITUDE) REMAINING GENERALLY ALONG AND
WEST OF THE MOUNTAINS. CONVECTION HAS GENERALLY REMAINED TO OUR EAST
INVOF THE WEAK FRONTAL ZONE AND TO OUR WEST WHERE CONVECTION
ORIGINATED OVER THE HIGHER TERRAIN AND HAS MOVED SLOWLY EASTWARD.
HOWEVER... SOME OF THE SHOWERS AND STORMS WHICH ORIGINATED OVER THE
HIGHER TERRAIN ARE NOW MAKING MOVING INTO OUR NORTHWEST PIEDMONT.
EXPECT THIS CONVECTION TO BEGIN TO WANE AS IT CONTINUES TO SLOWLY
MOVE EASTWARD ACROSS THE NORTHWEST PIEDMONT OVER THE NEXT HOUR OR
SO... GIVEN LACK OF OVERALL INSTABILITY (~500 MLCAPE AND AROUND 500
MUCAPE)... WHICH IS GENERALLY SUPPORTED BY HIRES MODELS. DO NOT
EXPECT ANY OF THIS ACTIVITY TO BE SEVERE GIVEN THE LACK OF
INSTABILITY AND CURRENT RADAR TRENDS. EXPECT THE STRONGEST STORMS
(IF ANY) COULD PRODUCE 30-35 MPH WIND GUSTS AND VERY SMALL HAIL.
THUS... HAVE REMOVED MENTION OF SEVERE STORMS FROM THE DAY ONE
SECTION OF THE HWO. HOWEVER... WE MAY SEE SOME SHOWERS AND PERHAPS
ISOLATED STORMS MOVE INTO SOUTHERN/SOUTHEASTERN PORTIONS OF THE AREA
TONIGHT AS ANOTHER IMPULSE ALOFT AND WEAK SURFACE WAVE TRACK ALONG
THE WEAK FRONT/TROUGH (GENERALLY AFTER MIDNIGHT). THIS IS SUPPORTED
BY THE LATEST RAP AND SOMEWHAT BY THE LAST FEW RUNS OF THE HRRR.
THUS... WILL BUMP POPS UP IN THE SOUTHEAST TO CHANCE GENERALLY AFTER
05/06Z OR SO. THINK WE WILL HAVE ENOUGH MID/HIGH LEVEL MOISTURE
ACROSS THE AREA TO SEE TOO MUCH FOG. THUS... WILL JUST MENTION
PATCHY FOG... WITH LOW STRATUS DEVELOPING/MOVING INTO THE AREA
OVERNIGHT. EXPECT OVERNIGHT LOWS TO GENERALLY BE IN THE MID TO UPPER
60S. -BSD
FOR TUESDAY THE CHANCES FOR SEVERE WEATHER FOR TOMORROW AFTERNOON
WILL BE A BIT BETTER WITH MORE INSTABILITY AVAILABLE BUT IT WILL BE
CONFINED TO EASTERN PORTIONS OF THE CWA AND SHOULD STILL BE
ISOLATED. SHEAR WILL STILL BE PLENTIFUL AS THE JET CONTINUES TO MAKE
AN EXIT TO THE NORTHEAST. DURING THE AFTERNOON HOURS A 500 MB VORT
MAX SHOULD MAKE HEADWAY UP THE COAST BUT WHETHER OR NOT THIS FEATURE
PASSES CLOSE ENOUGH TO THE EASTERN PERIPHERY TO HELP SUPPORT
CONVECTION REMAINS TO BE SEEN. SURFACE HIGH PRESSURE TO THE
NORTHWEST WILL START TO WORK INTO THE AREA...POTENTIALLY CONFINING
CONVECTION EVEN FURTHER TO THE EAST DEPENDING ON PROGRESS. WHILE THE
UPPER LEVEL TROUGH WILL STILL BE IN PLACE IT WILL BEGIN TO LIFT OUT
AS THE UPPER JET CONTINUES UP THE EASTERN SEABOARD. MAX TEMPERATURES
TUESDAY WILL BE IN THE LOWER 80S WITH LOWS TUESDAY NIGHT IN THE MID
60S. -ELLIS
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...
WEDNESDAY AND WEDNESDAY NIGHT:
THE LATEST 12Z MODEL GUIDANCE INDICATES SHORTWAVE ENERGY DIGGING
SOUTHEAST THROUGH THE CENTRAL PLAINS ON TUE...AND INTO THE LOWER MS
RIVER VALLEY/DEEP SOUTH ON WED...PROGRESSING EASTWARD INTO THE
SOUTHEAST STATES WED NIGHT...WITH A LOW-LEVEL TROUGH (OR WEAK
SFC-H85 LOW) DOWNSTREAM OVER THE EASTERN CAROLINAS. A SHEAR AXIS IS
EXPECTED TO EXTEND SW-NE ALONG THE APPALACHIANS IN BOTH WED/WED
NIGHT...PROGRESSING SLOWLY EASTWARD TOWARD THE CENTRAL CAROLINAS/VA.
UNCERTAINTY PERSISTS W/REGARD TO THE EVOLUTION OF UPSTREAM SHORTWAVE
ENERGY...LENDING UNCERTAINTY TO THE LOW-LEVEL PATTERN OVER THE
CAROLINAS WED/WED NIGHT. AS A RESULT...A FAIR AMOUNT OF UNCERTAINTY
IS PRESENT WITH TEMPERATURES...CLOUD COVER AND PRECIPITATION
CHANCES...ESPECIALLY DURING THE DAY WED. HOWEVER...MODEL GUIDANCE IS
IN RELATIVELY GOOD AGREEMENT ON THE OVERALL PATTERN...WHICH WOULD
SUGGEST MORE CLOUD COVER...COOLER TEMPERATURES AND BETTER CHANCES
FOR SHOWER ACTIVITY IN EASTERN PORTIONS OF THE AREA. WILL INDICATE
PRECIP CHANCES RANGING FROM 20-40% ON WED (HIGHEST EAST)...WITH
HIGHS IN THE MID 80S WEST TO NEAR 80F EAST. FOR WED NIGHT...MODEL
GUIDANCE INDICATES THE AFOREMENTIONED SHEAR AXIS SLOWLY PROGRESSING
EASTWARD TOWARD THE CENTRAL CAROLINAS...WITH THE MORE POTENT
SHORTWAVE ENERGY OVER THE SOUTHEAST STATES DEAMPLIFYING AS IT
PROGRESSES TOWARD THE SOUTHEAST COAST. WILL INDICATE 20-30% CHANCES
THROUGH MIDNIGHT (HIGHEST EAST)...WITH 20% IN THE COASTAL PLAIN
THROUGH SUNRISE THU...DRY ELSEWHERE. LOWS THU MORNING EXPECTED TO
RANGE FROM THE LOWER 60S (WEST) TO MID/UPPER 60S (EAST). -VINCENT
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...
THE LATEST LONG RANGE MODEL GUIDANCE INDICATES A CHANGE IN THE
SYNOPTIC PATTERN OVER THE REGION THIS WEEKEND THROUGH EARLY NEXT
WEEK...WITH TROUGHING OVER THE EASTERN CONUS GIVING WAY TO A
STRENGTHENING UPPER LEVEL RIDGE OVER THE EAST COAST...AND
UNSEASONABLY STRONG SURFACE HIGH PRESSURE EXTENDING SOUTHWARD FROM
NEW ENGLAND INTO THE MID-ATLANTIC AND CAROLINAS. THE PRIMARY
UNCERTAINTY W/REGARD TO THE EXTENDED FORECAST APPEARS TO REVOLVE
AROUND THE EVOLUTION OF A POTENTIAL TROPICAL SYSTEM LATE IN THE
EXTENDED PERIOD (EARLY NEXT WEEK). AT THIS POINT...EXPECT NEAR
NORMAL TEMPERATURES AND PRECIP CHANCES ON THU-FRI...FOLLOWED BY NEAR
NORMAL TEMPERATURES AND BELOW NORMAL PRECIP CHANCES OVER THE
WEEKEND. AS MENTIONED ABOVE...UNCERTAINTY INCREASES CONSIDERABLY BY
EARLY NEXT WEEK...AND AT THIS TIME WILL INDICATE CLIMATOLOGICAL
CONDITIONS ON MONDAY. -VINCENT
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 130 AM TUESDAY...
MOST SITES ARE REPORTING EITHER VFR CONDITIONS OF MVFR VSBYS EARLY
THIS MORNING...WITH SOME PATCHY RAIN MOVING FROM SC INTO
SOUTHEASTERN NC. WITH WIDESPREAD MID AND HIGH CLOUDS OVER THE AREA
AND LITTLE RAIN...VSBYS SHOULD HOLD ABOVE 3SM FOR MOST
SITES...THOUGH A PERIOD OF LIFR VSBYS IS POSSIBLY BY 12Z. ONE AREA
OF CONCERN IS THE WESTERN PIEDMONT WHERE THE BACK EDGE OF THE
MID/HIGH CLOUDS IS APPROACHING KINT AND KGSO. IF SKIES CAN CLEAR OFF
OVER THE TRIAD...THEN IFR/LIFR VSBYS ARE POSSIBLE.
SCATTERED SHOWERS AND STORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON...THOUGH THERE IS SOME UNCERTAINTY REGARDING THE COVERAGE
OVER CENTRAL NC AS THE AXIS OF BETTER DEEP MOISTURE HAS SHIFTED
FURTHER EAST TO THE COAST. AN UPPER LEVEL DISTURBANCE APPROACHING
FROM THE WEST LATER THIS AFTERNOON AND EVENING SHOULD HELP KICK OFF
SOME CONVECTION OVER WESTERN NC BY 00Z.
OUTLOOK...
WHILE THERE REMAINS A CHANCE OF SHOWERS AND STORMS
WEDNESDAY AFTERNOON...A GENERAL IMPROVEMENT IN AVIATION CONDITIONS
IS EXPECTED THROUGH THE END OF THE WEEK AS THE UPPER LEVEL TROUGH
OVER THE REGION WEAKENS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...BSD/ELLIS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
426 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A RATHER POTENT MID LEVEL SHORT WAVE AND A WEAK SURFACE TROUGH
WILL COMBINE TO PRODUCE A CHANCE OF SHOWERS AND THUNDERSTORMS
TODAY. THEREAFTER...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
BRING WARM AND DRY WEATHER FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE DEVELOPED FROM CINCINNATI THROUGH LIMA EARLY THIS
MORNING AHEAD OF A RATHER SHARP SHORT WAVE TROUGH. EXPECT SHOWERS
AND A FEW THUNDERSTORMS TO EXPAND EASTWARD INTO THIS AFTERNOON
AIDED BY INCREASING INSTABILITY DUE TO DAYTIME HEATING. THE TROUGH
AND ASSOCIATED MOISTURE WILL BE MOVING EAST OF THE AREA BY LATE
AFTERNOON...WHICH WILL BRING AN END TO THE PRECIPITATION. THE CHANCE
FOR SEVERE THUNDERSTORMS APPEARS LOW DUE TO WEAK INSTABILITY AND
WIND FIELDS ACCOMPANYING THE SHORT WAVE. TEMPERATURES WILL TOP OUT
AROUND 80 THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
SKIES WILL CLEAR TONIGHT AS THE SHORT WAVE MOVES WELL EAST OF THE
REGION AND HIGH PRESSURE STARTS TO BUILD AT ALL LEVELS OF THE
ATMOSPHERE. THE HIGH WILL BE ANCHORED TO THE EAST THROUGH
THURSDAY...WHILE 500 MB HEIGHTS INCREASE TO ABOVE 5900 METERS.
THIS WILL RESULT IN A PERIOD OF PERSISTENTLY DRY WEATHER...AND
GRADUALLY INCREASING TEMPERATURES. UNDER MOSTLY SUNNY SKIES AND
MODERATE WARM ADVECTION...HIGHS ON WEDNESDAY WILL BE IN THE LOWER
TO MIDDLE 80S...RISING TO THE MIDDLE AND UPPER 80S ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
SLOWLY BUILDING UPPER HEIGHTS ALONG WITH SOUTHERLY FLOW ON THE BACK
SIDE OF A SURFACE HIGH WILL RESULT IN ABOVE NORMAL TEMPERATURES AND
DRY CONDITIONS THROUGH THE PERIOD. THERE IS SOME POSSIBILITY THAT A
WEAK BOUNDARY COULD APPROACH THE NORTHWEST COUNTIES EARLY NEXT WEEK.
BUT CHANCE OF RAIN REMAINS QUITE LOW AT THIS POINT.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
MID LEVEL S/W ENERGY PUSHING ACROSS INDIANA SET OFF A FEW SHOWERS
ALONG THE INDIANA/OHIO BORDER. LATEST HRRR RUN APPEARS TO HAVE A
HANDLE ON THESE SHOWERS...WHICH ARE EXPECTED TO LIFT NE AND
CONTINUE TO WEAKEN EARLY THIS MORNING. A BRIEF SHOWER WILL BE PSBL
EARLY BUT CONDITIONS ARE EXPECTED TO REMAIN VFR. HAVE HANDLED THIS
WITH A MENTION OF VCSH. EXPECT MID LEVEL CIGS WHICH WILL ACT TO
MITIGATE FOG FORMATION. IF WE END UP WITH MORE BREAKS THAN
NOT...SOME MVFR BR WILL BE POSSIBLE...ESPECIALLY AT THE MORE
FAVORABLE KLUK AND POSSIBLY KILN.
AS THE ASSOCIATED LOW LEVEL TROUGH AXIS TRACKS EAST THROUGH THE
DAY...EXPECT ISOLATED TO SCATTERED SHOWER DEVELOPMENT AS THE AIRMASS
DESTABILIZES THROUGH THE AFTERNOON HOURS. EXACT LOCATION OF ANY
INITIATION REMAINS SOMEWHAT UNCERTAIN. HAVE CONTINUED A MENTION OF
VCSH IN ALL TAFS THIS AFTN. WITH THE PASSAGE OF THE TROF AXIS THE
THREAT OF PRECIPITATION WILL END BY EVENING.
.OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
211 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A COUPLE OF UPPER LEVEL DISTURBANCES WILL MOVE THROUGH THE
FORECAST AREA THROUGH TUESDAY EVENING KEEPING PRECIPITATION
CHANCES IN THE FORECAST ACROSS THE REGION. HIGH PRESSURE WILL THEN
MOVE INTO THE AREA FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A MID LEVEL SHORT WAVE IS PROGRESSING SLOWLY EAST ACROSS THE
REGION THIS EVENING. THIS IS HELPING TO MAINTAIN SOME SHOWER AND
THUNDERSTORM ACTIVITY ACROSS PARTS OF INDIANA AND INTO NORTHWEST
OHIO. THIS ACTIVITY HAS SHOWN A GRADUAL WEAKENING TREND AND WOULD
EXPECT THAT TO CONTINUE AS IT PUSHES EAST INTO OUR WESTERN AREA
THROUGH LATE EVENING. WE PRETTY MUCH LOSE ALL INSTABILITY BY 06Z
SO WILL JUST HANG ON TO A SLIGHT CHANCE OF SHOWERS ACROSS
PRIMARILY THE WEST THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. AT
THE MOMENT...SKIES HAVE GENERALLY CLEARED OFF ACROSS OUR FA BUT DO
EXPECT TO SEE AT LEAST A PARTIAL INCREASE IN CLOUDS THROUGH THE
OVERNIGHT HOURS AS SHORT WAVE MOVES IN. WILL STICK WITH LOWS IN
THE MID 50S...BUT THIS COULD BE ON THE COOL SIDE IF WE END UP WITH
ENOUGH CLOUDS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
ANOTHER UPPER LEVEL DISTURBANCE WILL WORK THROUGH THE FA ON
TUESDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
DURING THE DAY AS THIS FEATURE MOVES THROUGH THE REGION. A FEW OF
THE STORMS MAY PRODUCE SOME HAIL ON TUESDAY. WITH ADDITIONAL
CLOUD COVER AND PRECIPITATION ACROSS THE FA ON TUESDAY HIGH
TEMPERATURES WILL BE LIMITED TO THE MIDDLE 70S TO AROUND 80.
PRECIPITATION WILL TAPER OFF BY THE EVENING HOURS ON TUESDAY AND
HIGH PRESSURE WILL WORK INTO THE FA FOR THE REMAINDER OF THE SHORT
TERM TIME FRAME. TEMPERATURES WILL BE SLIGHTLY WARMER ON WEDNESDAY
WITH MORE SUNSHINE ACROSS THE AREA. HIGHS ON WEDNESDAY WILL REACH
UP INTO THE LOWER 80S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
SLOWLY BUILDING UPPER HEIGHTS ALONG WITH SOUTHERLY FLOW ON THE BACK
SIDE OF A SURFACE HIGH WILL RESULT IN ABOVE NORMAL TEMPERATURES AND
DRY CONDITIONS THROUGH THE PERIOD. THERE IS SOME POSSIBILITY THAT A
WEAK BOUNDARY COULD APPROACH THE NORTHWEST COUNTIES EARLY NEXT WEEK.
BUT CHANCE OF RAIN REMAINS QUITE LOW AT THIS POINT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MID LEVEL S/W ENERGY PUSHING ACROSS INDIANA SET OFF A FEW SHOWERS
ALONG THE INDIANA/OHIO BORDER. LATEST HRRR RUN APPEARS TO HAVE A
HANDLE ON THESE SHOWERS...WHICH ARE EXPECTED TO LIFT NE AND
CONTINUE TO WEAKEN EARLY THIS MORNING. A BRIEF SHOWER WILL BE PSBL
EARLY BUT CONDITIONS ARE EXPECTED TO REMAIN VFR. HAVE HANDLED THIS
WITH A MENTION OF VCSH. EXPECT MID LEVEL CIGS WHICH WILL ACT TO
MITIGATE FOG FORMATION. IF WE END UP WITH MORE BREAKS THAN
NOT...SOME MVFR BR WILL BE POSSIBLE...ESPECIALLY AT THE MORE
FAVORABLE KLUK AND POSSIBLY KILN.
AS THE ASSOCIATED LOW LEVEL TROUGH AXIS TRACKS EAST THROUGH THE
DAY...EXPECT ISOLATED TO SCATTERED SHOWER DEVELOPMENT AS THE AIRMASS
DESTABILIZES THROUGH THE AFTERNOON HOURS. EXACT LOCATION OF ANY
INITIATION REMAINS SOMEWHAT UNCERTAIN. HAVE CONTINUED A MENTION OF
VCSH IN ALL TAFS THIS AFTN. WITH THE PASSAGE OF THE TROF AXIS THE
THREAT OF PRECIPITATION WILL END BY EVENING.
.OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...JGL
SHORT TERM...NOVAK
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
148 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A LARGE UPPER LEVEL TROUGH CARVED OUT OVER THE EASTERN HALF OF THE
U.S. WILL GRADUALLY WEAKEN INTO THE SECOND HALF OF THE WEEK. HIGH
PRESSURE SHOULD BECOME THE MAIN WEATHER FEATURE BY THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LAST REMAINING VESTIGES OF EARLIER CONVECTION FOCUSED ALONG
SHORTWAVE TRACKING ACROSS SOUTH CENTRAL MOUNTAINS NOW PETERING OUT
OVER FRANKLIN AND ADAMS COUNTIES...AND WILL BY GONE BY 06Z.
FAVORABLE RADIATIONAL COOLING AND SFC RH/S NR 100 PCT WILL RESULT
IN WIDESPREAD AND LOCALLY DENSE VALLEY FOG EARLY THIS MORNING.
USED A BLEND OF MET AND RUC DATA FOR OVERNIGHT LOWS...WHICH SHOULD
RANGE FROM THE U40S NW MTNS TO M/U50S ACROSS THE LOWER SUSQ
VALLEY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
FOG SHOULD BURN OFF TO MSUNNY SKIES BY LATE AM. HOWEVER...DIURNAL
HEATING COMBINED WITH APPROACH OF UPPER LVL TROF SHOULD YIELD
INCREASING CU AND SCT SHRA/TSRA BY AFTN. PWAT VALUES ARE LOWER
THAN MONDAY...SO COVERAGE OF PRECIP SHOULD BE LESS WIDESPREAD.
ELEVATED TERRAIN AND PROXIMITY TO UPPER TROF WILL FAVOR THE
WESTERN AND CENTRAL MTNS FOR HIGHER /CHC/ POPS...WHILE ONLY WIDELY
SCT /SCHC/ POPS EXPECTED ACROSS THE EASTERN COUNTIES. MORE
SUNSHINE WILL RESULT IN A SLIGHTLY WARMER DAY THAN TODAY...WITH
MDL 8H TEMPS SUPPORTIVE OF HIGHS FROM THE L/M70S OVR THE
ALLEGHENIES...TO ARND 80F OVR THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE NORTHEAST U.S. WILL REMAIN IN AN UPPER TROUGH THROUGH LATE
WEEK. HOWEVER...SURFACE HIGH PRESSURE WILL INFILTRATE THE REGION
DURING THE DAY WEDNESDAY. LEFT AN ISOLATED THREAT FOR A
THUNDERSTORM OVER THE EASTER CWA WEDNESDAY AFTERNOON BUT A
MAJORITY OF THE FORECAST AREA WILL SEE DRY WEATHER.
THE UPPER TROUGH FILLS AND WE MOVE TO A MORE ZONAL FLOW ON
THURSDAY. WITH SURFACE HIGH PRESSURE...TEMPERATURES WILL RISE TO
SLIGHTLY ABOVE SEASONAL AVERAGES.
A SLIGHTLY MUDDIED PICTURE SHOWN BY THE EXTENDED MODELS WITH A
FEW UPPER LEVEL RIPPLES MOVE THROUGH THE REGION AS A 500 MB
HEIGHTS REMAIN HIGH OVER THE SOUTHWEST U.S. TIMING OF ANY AREAS OF
PRECIP IS DIFFICULT THIS FAR OUT SO LEFT A MORE OPTIMISTIC OUTLOOK
UNTIL SOMETHING GROWS HORNS.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
FAVORABLE RADIATIONAL COOLING AND SFC RH/S NR 100 PCT WILL RESULT
IN WDSPRD VALLEY FOG EARLY THIS MORNING. EXPECT CIGS AND VSBYS TO
DETERIORATE FROM MVFR TO IFR WITH LCL CONDS AOB AIRFIELD MINS PSBL
AROUND DAYBREAK. FOG WILL BURN OFF BY 13-14Z WITH VFR CONDS
PREVAILING FM MID MORNING THRU THE AFTN. UPPER-AIR DISTURBANCE
MOVG EWD FM THE OH VLY COMBINED WITH DIURNAL INSTABILITY WILL
SUPPORT WDLY SCT SHOWERS AND TSTMS DURING THE AFTN. CONVECTION
WILL DISSIPATE WITH THE LOSS OF HEATING WITH CLR SKIES AND MORE
VALLEY FOG TONIGHT INTO EARLY WEDNESDAY.
OUTLOOK...
THU-SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...TYBURSKI
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1224 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A LARGE UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE U.S. WILL
DOMINATE THE REGIONAL WEATHER PATTERN THROUGH WEDNESDAY.
DISTURBANCES ALOFT WILL ROTATE AROUND THE UPPER LEVEL TROUGH AND
KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST EARLY THIS WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LAST REMAINING VESTIGES OF EARLIER CONVECTION FOCUSED ALONG
SHORTWAVE TRACKING ACROSS SOUTH CENTRAL MOUNTAINS NOW PETERING OUT
OVER FRANKLIN AND ADAMS COUNTIES...AND WILL BY GONE BY 06Z.
CLEARING SKIES...A LGT WIND AND WET GROUND ALREADY RESULTING IN
PATCHY FOG AT 0230Z AND EXPECT IT TO BECOME WIDESPREAD AND LOCALLY
DENSE LATE TONIGHT. GFS EXPERIENCING KNOWN ISSUE OF LOW LVL TEMPS
BEING TOO COOL. THUS...HAVE USED A BLEND OF MET AND RUC DATA FOR
OVERNIGHT LOWS...WHICH SHOULD RANGE FROM THE U40S NW MTNS...TO
M/U50S ACROSS THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
FOG SHOULD BURN OFF TO MSUNNY SKIES BY LATE AM. HOWEVER...DIURNAL
HEATING COMBINED WITH APPROACH OF UPPER LVL TROF SHOULD YIELD
INCREASING CU AND SCT SHRA/TSRA BY AFTN. PWAT VALUES ARE LOWER
THAN MONDAY...SO COVERAGE OF PRECIP SHOULD BE LESS WIDESPREAD.
ELEVATED TERRAIN AND PROXIMITY TO UPPER TROF WILL FAVOR THE
WESTERN AND CENTRAL MTNS FOR HIGHER /CHC/ POPS...WHILE ONLY WIDELY
SCT /SCHC/ POPS EXPECTED ACROSS THE EASTERN COUNTIES. MORE
SUNSHINE WILL RESULT IN A SLIGHTLY WARMER DAY THAN TODAY...WITH
MDL 8H TEMPS SUPPORTIVE OF HIGHS FROM THE L/M70S OVR THE ALLEGHENIES...TO
ARND 80F OVR THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE NORTHEAST U.S. WILL REMAIN IN AN UPPER TROUGH THROUGH LATE
WEEK. HOWEVER...SURFACE HIGH PRESSURE WILL INFILTRATE THE REGION
DURING THE DAY WEDNESDAY. LEFT AN ISOLATED THREAT FOR A
THUNDERSTORM OVER THE EASTER CWA WEDNESDAY AFTERNOON BUT A
MAJORITY OF THE FORECAST AREA WILL SEE DRY WEATHER.
THE UPPER TROUGH FILLS AND WE MOVE TO A MORE ZONAL FLOW ON
THURSDAY. WITH SURFACE HIGH PRESSURE...TEMPERATURES WILL RISE TO
SLIGHTLY ABOVE SEASONAL AVERAGES.
A SLIGHTLY MUDDIED PICTURE SHOWN BY THE EXTENDED MODELS WITH A
FEW UPPER LEVEL RIPPLES MOVE THROUGH THE REGION AS A 500 MB
HEIGHTS REMAIN HIGH OVER THE SOUTHWEST U.S. TIMING OF ANY AREAS OF
PRECIP IS DIFFICULT THIS FAR OUT SO LEFT A MORE OPTIMISTIC OUTLOOK
UNTIL SOMETHING GROWS HORNS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MINOR ADJUSTMENTS TO 03Z TAFS.
SKIES STARTING TO CLEAR TO THE WEST...SO STILL EXPECT FOG
TO FORM...PERHAPS NOT QUITE AS FAST AS I HAD IN THE 00Z
TAFS.
SHOWERS AND STORMS JUST ABOUT GONE NOW.
EARLIER DISCUSSION BELOW.
MAIN ISSUE WILL BE DENSE FOG LATE...IFR AND LIFR CONDITIONS
LIKELY.
EXPECT THINGS TO IMPROVE BY MID MORNING ACROSS MOST OF THE
AREA ON TUE. LOWER CHC FOR SHOWERS AND STORMS ON TUE THAN
TODAY.
HOWEVER...SOME CHC FOR SHOWERS AND STORMS TUESDAY NIGHT INTO
WED...AS ANOTHER UPPER LVL SYSTEM ROTATES AROUND THE DEEP
VORTEX.
ALONG WITH THE CHC OF SHOWERS AND STORMS TUESDAY NIGHT...FOG
WILL LIKELY FORM AGAIN.
IMPROVING CONDITIONS STILL EXPECTED LATER IN THE WEEK...AS THE
UPPER LVL FLOW BECOMES MORE ZONAL...THAT IS WEST TO EAST...FOR
A CHANGE...AND TEMPS WARM SOME.
OUTLOOK...
THU-SAT...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CERU/STEINBUGL
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...DANGELO/FITZGERALD
LONG TERM...TYBURSKI
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1139 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A WEAK COLD FRONTAL WILL CROSS THE STATE TODAY INTO TONIGHT WITH
SOME SHOWERS POSSIBLE. ANOTHER WEAK DISTURBANCE WILL MOVE ACROSS THE
REGION ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
11:40 AM UPDATE...SHOWERS ARE TAPERING OFF. ONLY A FEW VERY LIGHT
SPOTTY SHOWERS REMAIN IN EASTERN AREAS AND THESE WILL DISSIPATE
EARLY THIS AFTERNOON. THE SKY WILL TURN OUT SUNNY TO PARTLY CLOUDY
WITH A DRY AFTERNOON. LOWERED TEMPS JUST A COUPLE DEGREES SINCE
CLOUD COVER THIS MORNING SLOWED THE INCREASE IN TEMPS A BIT.
PREVIOUS DISCUSSION...
MAIN CHALLENGE THIS TERM WILL BE SHOWER ACTIVITY AND QPF.
LATEST RADAR SHOWED ACTIVITY MOVING INTO WNW MAINE THIS MORNING
W/ECHOES UP TO 30DBZ WHICH LEADS TO THE POTENTIAL FOR SOME SHOWER
ACTIVITY TO REACH THE GROUND. SATL IMAGERY & CEILING PLOTS
INDICATED CLOUD DECKS OF 7K-10K FT. THIS IS REFLECTED IN THE UPPER
AIR ANALYSIS. THE LATEST NAM AND GFS HAVE INITIALIZED WELL W/THE
LATEST RADAR IMAGERY. HRRR INITIALIZED WELL BUT SEEMS TO BE
OVERDONE W/ITS RAINFALL OVERSPREADING THE CWA BY LATE MORNING INTO
THE AFTERNOON. MID LEVEL FORCING ALONG W/LLVL CONVERGENCE ALONG
AND JUST AHEAD OF THE FRONTAL BOUNDARY WILL ALLOW FOR SHOWERS
TODAY. ATTM, USED A BLEND OF THE NAM12 AND GFS FOR THE POPS WHICH
SHOW 20-40% ACROSS THE CWA EXCEPT THE COAST. HPC QPF LOOKS
OVERDONE AND TOO FAR SOUTH. THEREFORE, DECIDED TO BLEND THE
NAM12/HPC AND SREF FOR QPF WHICH SHOWS NO MORE THAN .10 OF AN INCH
AND THIS WILL BE MAINLY ACROSS THE CENTRAL AND EASTERN AREAS.
STAYED CLOSE W/THE DAYCREW`S MAXES FOR TODAY W/MID 70S NORTH AND
UPPER 70S TO AROUND 80 FOR THE CENTRAL AND DOWNEAST AREAS. ANOTHER
FACTOR TODAY WILL BE WINDS AND MDL SOUNDINGS INDICATE AN INVERTED
V-SOUNDING WHICH SUPPORTS SOME WIND TO POSSIBLY MIX DOWN. DECIDED
TO BOOST WIND GUSTS TO 20 MPH MAINLY ACROSS THE HIGHER TERRAIN AND
OPEN AREAS.
TONIGHT WILL SEE CLOUDS BEGINNING TO BREAK UP AS THE FRONT SLOWLY
SLIDES TO THE EAST. SOME CAA IS SEEN BEHIND THE FRONT AND W/WINDS
BECOMING LIGHT AND A WET GROUND, THINKING HERE IS THAT SOME FOG
WILL FORM. BUFKIT PROFILES SUPPORT THIS THINKING. MID LEVEL MOISTURE
IS SHOWN BY THE GFS AND NAM TO MOVE ACROSS NORTHERN AREAS OVERNIGHT.
THIS COULD HALT FURTHER PROGRESSION OF THE FOG. ADDED FOG TO THE
FORECAST BUT NOT CONFIDENT TO GO ANY MORE THAN USING PATCHY
WORDING. DAYCREW CAN ASSESS THIS FURTHER. TEMPERATURES WILL BE
COOL W/MINS DROPPING BACK INTO THE MID AND UPPER 40S ACROSS THE
NORTH AND WEST AND LOW TO MID 50S FOR THE CENTRAL AND DOWNEAST
REGIONS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN TO OUR SOUTH ON WEDNESDAY AS LOW
PRESSURE MOVES EAST ACROSS ONTARIO/QUEBEC PROVINCE. THIS WILL KEEP
A SOUTHWEST FLOW AND WEAK WARM ADVECTION ACROSS THE REGION ON
WEDNESDAY WITH PARTLY/MOSTLY SUNNY SKIES. HIGHS ON WEDNESDAY WILL
RANGE FROM THE LOW/MID 70S NORTH AND UPPER 70S TO NEAR 80
DOWNEAST. A DRY NIGHT CAN BE EXPECTED WEDNESDAY NIGHT AS LOW
PRESSURE CONTINUES TO SLIDE TO OUR NORTH. LOWS WEDNESDAY NIGHT
WILL RANGE FROM THE LOW TO MID 50S. A COLD FRONT WILL SLIDE ACROSS
THE REGION ON THURSDAY. SB CAPES ARE UNIMPRESSIVE SO WILL NOT
INCLUDE THE MENTION OF THUNDER BUT WILL MENTION THE CHANCE FOR
AFTERNOON SHOWERS MAINLY ACROSS NORTHERN AND CENTRAL AREAS. HIGH
ON THURSDAY WILL RANGE FROM THE MID TO UPPER 70S NORTH AND LOW TO
MID 80S DOWNEAST...BUT IT WILL BE COOLER NEAR THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THURSDAY NIGHT AND
FRIDAY. THIS WILL BRING MAINLY CLEAR SKIES TO THE REGION THURSDAY
NIGHT AND MOSTLY SUNNY SKIES ON FRIDAY. HIGH PRESSURE WILL SLIDE
EAST ON SATURDAY AND SUNDAY WITH CONTINUED DRY WEATHER. A FRONT WILL
APPROACH FROM THE WEST SUNDAY NIGHT WITH INCREASING CLOUDS. THE
FRONT WILL SLIDE EAST ACROSS THE REGION MONDAY WITH THE CHANCE FRO
SHOWERS.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: STAYED CLOSE TO VFR INTO TONIGHT. SOME PATCHY FOG
COULD ALLOW FOR BRIEF MVFR/IFR CONDITIONS AT THE AIRFIELDS EARLY
WEDNESDAY MORNING. FOG SHOULD LIFT AND BURN OFF BY 8 AM.
SHORT TERM: MAINLY VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM: NO HEADLINES. SSE SWELL WILL CONTINUE THROUGH THE
PERIOD W/WAVE HEIGHTS OF 2-3 FT AND THIS WILL MAINLY BE AWAY FROM
THE INTRA-COASTAL WATERS. WINDS WILL LIGHT AVERAGING 5-10 KTS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SCA LEVELS THROUGH THE
PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MCB
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1011 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A WEAK COLD FRONTAL WILL CROSS THE STATE TODAY INTO TONIGHT WITH
SOME SHOWERS POSSIBLE. ANOTHER WEAK DISTURBANCE WILL MOVE ACROSS THE
REGION ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10:00 AM UPDATE...SHOWERS CONTINUE MOVING EAST AND SATELLITE
IMAGERY SHOWS CLEARING FOLLOWING THIS LINE OF SHOWERS SO UPDATED
FORECAST TO GO PARTLY TO MOSTLY SUNNY THIS AFTERNOON FOLLOWING
THE PASSAGE OF THE FRONT.
PREVIOUS DISCUSSION...
MAIN CHALLENGE THIS TERM WILL BE SHOWER ACTIVITY AND QPF.
LATEST RADAR SHOWED ACTIVITY MOVING INTO WNW MAINE THIS MORNING
W/ECHOES UP TO 30DBZ WHICH LEADS TO THE POTENTIAL FOR SOME SHOWER
ACTIVITY TO REACH THE GROUND. SATL IMAGERY & CEILING PLOTS
INDICATED CLOUD DECKS OF 7K-10K FT. THIS IS REFLECTED IN THE UPPER
AIR ANALYSIS. THE LATEST NAM AND GFS HAVE INITIALIZED WELL W/THE
LATEST RADAR IMAGERY. HRRR INITIALIZED WELL BUT SEEMS TO BE
OVERDONE W/ITS RAINFALL OVERSPREADING THE CWA BY LATE MORNING INTO
THE AFTERNOON. MID LEVEL FORCING ALONG W/LLVL CONVERGENCE ALONG
AND JUST AHEAD OF THE FRONTAL BOUNDARY WILL ALLOW FOR SHOWERS
TODAY. ATTM, USED A BLEND OF THE NAM12 AND GFS FOR THE POPS WHICH
SHOW 20-40% ACROSS THE CWA EXCEPT THE COAST. HPC QPF LOOKS
OVERDONE AND TOO FAR SOUTH. THEREFORE, DECIDED TO BLEND THE
NAM12/HPC AND SREF FOR QPF WHICH SHOWS NO MORE THAN .10 OF AN INCH
AND THIS WILL BE MAINLY ACROSS THE CENTRAL AND EASTERN AREAS.
STAYED CLOSE W/THE DAYCREW`S MAXES FOR TODAY W/MID 70S NORTH AND
UPPER 70S TO AROUND 80 FOR THE CENTRAL AND DOWNEAST AREAS. ANOTHER
FACTOR TODAY WILL BE WINDS AND MDL SOUNDINGS INDICATE AN INVERTED
V-SOUNDING WHICH SUPPORTS SOME WIND TO POSSIBLY MIX DOWN. DECIDED
TO BOOST WIND GUSTS TO 20 MPH MAINLY ACROSS THE HIGHER TERRAIN AND
OPEN AREAS.
TONIGHT WILL SEE CLOUDS BEGINNING TO BREAK UP AS THE FRONT SLOWLY
SLIDES TO THE EAST. SOME CAA IS SEEN BEHIND THE FRONT AND W/WINDS
BECOMING LIGHT AND A WET GROUND, THINKING HERE IS THAT SOME FOG
WILL FORM. BUFKIT PROFILES SUPPORT THIS THINKING. MID LEVEL MOISTURE
IS SHOWN BY THE GFS AND NAM TO MOVE ACROSS NORTHERN AREAS OVERNIGHT.
THIS COULD HALT FURTHER PROGRESSION OF THE FOG. ADDED FOG TO THE
FORECAST BUT NOT CONFIDENT TO GO ANY MORE THAN USING PATCHY
WORDING. DAYCREW CAN ASSESS THIS FURTHER. TEMPERATURES WILL BE
COOL W/MINS DROPPING BACK INTO THE MID AND UPPER 40S ACROSS THE
NORTH AND WEST AND LOW TO MID 50S FOR THE CENTRAL AND DOWNEAST
REGIONS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN TO OUR SOUTH ON WEDNESDAY AS LOW
PRESSURE MOVES EAST ACROSS ONTARIO/QUEBEC PROVINCE. THIS WILL KEEP
A SOUTHWEST FLOW AND WEAK WARM ADVECTION ACROSS THE REGION ON
WEDNESDAY WITH PARTLY/MOSTLY SUNNY SKIES. HIGHS ON WEDNESDAY WILL
RANGE FROM THE LOW/MID 70S NORTH AND UPPER 70S TO NEAR 80
DOWNEAST. A DRY NIGHT CAN BE EXPECTED WEDNESDAY NIGHT AS LOW
PRESSURE CONTINUES TO SLIDE TO OUR NORTH. LOWS WEDNESDAY NIGHT
WILL RANGE FROM THE LOW TO MID 50S. A COLD FRONT WILL SLIDE ACROSS
THE REGION ON THURSDAY. SB CAPES ARE UNIMPRESSIVE SO WILL NOT
INCLUDE THE MENTION OF THUNDER BUT WILL MENTION THE CHANCE FOR
AFTERNOON SHOWERS MAINLY ACROSS NORTHERN AND CENTRAL AREAS. HIGH
ON THURSDAY WILL RANGE FROM THE MID TO UPPER 70S NORTH AND LOW TO
MID 80S DOWNEAST...BUT IT WILL BE COOLER NEAR THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THURSDAY NIGHT AND
FRIDAY. THIS WILL BRING MAINLY CLEAR SKIES TO THE REGION THURSDAY
NIGHT AND MOSTLY SUNNY SKIES ON FRIDAY. HIGH PRESSURE WILL SLIDE
EAST ON SATURDAY AND SUNDAY WITH CONTINUED DRY WEATHER. A FRONT WILL
APPROACH FROM THE WEST SUNDAY NIGHT WITH INCREASING CLOUDS. THE
FRONT WILL SLIDE EAST ACROSS THE REGION MONDAY WITH THE CHANCE FRO
SHOWERS.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: STAYED CLOSE TO VFR INTO TONIGHT. SOME PATCHY FOG
COULD ALLOW FOR BRIEF MVFR/IFR CONDITIONS AT THE AIRFIELDS EARLY
WEDNESDAY MORNING. FOG SHOULD LIFT AND BURN OFF BY 8 AM.
SHORT TERM: MAINLY VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM: NO HEADLINES. SSE SWELL WILL CONTINUE THROUGH THE
PERIOD W/WAVE HEIGHTS OF 2-3 FT AND THIS WILL MAINLY BE AWAY FROM
THE INTRA-COASTAL WATERS. WINDS WILL LIGHT AVERAGING 5-10 KTS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SCA LEVELS THROUGH THE
PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MCB
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
826 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A WEAK COLD FRONTAL WILL CROSS THE STATE TODAY INTO TONIGHT WITH
SOME SHOWERS POSSIBLE. ANOTHER WEAK DISTURBANCE WILL MOVE ACROSS THE
REGION ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
8:30 AM UPDATE...SOLID BAND OF SHOWERS IS MOVING EAST. AS OF 8:30
AM IT WAS ON A LINE FROM EASTERN AROOSTOOK COUNTY SOUTHWEST
ACROSS PENOBSCOT AND PISCATAQUIS COUNTIES. UPDATED TO FORECAST
NUMEROUS SHOWERS IN THIS BAND THIS MORNING. SHOWERS ARE LIGHT AND
SHOULD GIVE A TENTH OF AN INCH OR LESS OF RAINFALL AS IT MOVES
ACROSS. THE LINE OF SHOWERS SHOULD CLEAR THE AREA BY EARLY THIS
AFTERNOON.
PREVIOUS DISCUSSION...
MAIN CHALLENGE THIS TERM WILL BE SHOWER ACTIVITY AND QPF.
LATEST RADAR SHOWED ACTIVITY MOVING INTO WNW MAINE THIS MORNING W/ECHOES
UP TO 30DBZ WHICH LEADS TO THE POTENTIAL FOR SOME SHOWER ACTIVITY
TO REACH THE GROUND. SATL IMAGERY & CEILING PLOTS INDICATED CLOUD
DECKS OF 7K-10K FT. THIS IS REFLECTED IN THE UPPER AIR ANALYSIS.
THE LATEST NAM AND GFS HAVE INITIALIZED WELL W/THE LATEST RADAR
IMAGERY. HRRR INITIALIZED WELL BUT SEEMS TO BE OVERDONE W/ITS
RAINFALL OVERSPREADING THE CWA BY LATE MORNING INTO THE AFTERNOON.
MID LEVEL FORCING ALONG W/LLVL CONVERGENCE ALONG AND JUST AHEAD OF
THE FRONTAL BOUNDARY WILL ALLOW FOR SHOWERS TODAY. ATTM, USED A
BLEND OF THE NAM12 AND GFS FOR THE POPS WHICH SHOW 20-40% ACROSS
THE CWA EXCEPT THE COAST. HPC QPF LOOKS OVERDONE AND TOO FAR
SOUTH. THEREFORE, DECIDED TO BLEND THE NAM12/HPC AND SREF FOR QPF
WHICH SHOWS NO MORE THAN .10 OF AN INCH AND THIS WILL BE MAINLY
ACROSS THE CENTRAL AND EASTERN AREAS. STAYED CLOSE W/THE DAYCREW`S
MAXES FOR TODAY W/MID 70S NORTH AND UPPER 70S TO AROUND 80 FOR THE
CENTRAL AND DOWNEAST AREAS. ANOTHER FACTOR TODAY WILL BE WINDS AND
MDL SOUNDINGS INDICATE AN INVERTED V-SOUNDING WHICH SUPPORTS SOME
WIND TO POSSIBLY MIX DOWN. DECIDED TO BOOST WIND GUSTS TO 20 MPH
MAINLY ACROSS THE HIGHER TERRAIN AND OPEN AREAS.
TONIGHT WILL SEE CLOUDS BEGINNING TO BREAK UP AS THE FRONT SLOWLY
SLIDES TO THE EAST. SOME CAA IS SEEN BEHIND THE FRONT AND W/WINDS
BECOMING LIGHT AND A WET GROUND, THINKING HERE IS THAT SOME FOG
WILL FORM. BUFKIT PROFILES SUPPORT THIS THINKING. MID LEVEL MOISTURE
IS SHOWN BY THE GFS AND NAM TO MOVE ACROSS NORTHERN AREAS OVERNIGHT.
THIS COULD HALT FURTHER PROGRESSION OF THE FOG. ADDED FOG TO THE
FORECAST BUT NOT CONFIDENT TO GO ANY MORE THAN USING PATCHY
WORDING. DAYCREW CAN ASSESS THIS FURTHER. TEMPERATURES WILL BE
COOL W/MINS DROPPING BACK INTO THE MID AND UPPER 40S ACROSS THE
NORTH AND WEST AND LOW TO MID 50S FOR THE CENTRAL AND DOWNEAST REGIONS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN TO OUR SOUTH ON WEDNESDAY AS LOW
PRESSURE MOVES EAST ACROSS ONTARIO/QUEBEC PROVINCE. THIS WILL KEEP
A SOUTHWEST FLOW AND WEAK WARM ADVECTION ACROSS THE REGION ON
WEDNESDAY WITH PARTLY/MOSTLY SUNNY SKIES. HIGHS ON WEDNESDAY WILL
RANGE FROM THE LOW/MID 70S NORTH AND UPPER 70S TO NEAR 80
DOWNEAST. A DRY NIGHT CAN BE EXPECTED WEDNESDAY NIGHT AS LOW
PRESSURE CONTINUES TO SLIDE TO OUR NORTH. LOWS WEDNESDAY NIGHT
WILL RANGE FROM THE LOW TO MID 50S. A COLD FRONT WILL SLIDE ACROSS
THE REGION ON THURSDAY. SB CAPES ARE UNIMPRESSIVE SO WILL NOT
INCLUDE THE MENTION OF THUNDER BUT WILL MENTION THE CHANCE FOR
AFTERNOON SHOWERS MAINLY ACROSS NORTHERN AND CENTRAL AREAS. HIGH
ON THURSDAY WILL RANGE FROM THE MID TO UPPER 70S NORTH AND LOW TO
MID 80S DOWNEAST...BUT IT WILL BE COOLER NEAR THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THURSDAY NIGHT AND
FRIDAY. THIS WILL BRING MAINLY CLEAR SKIES TO THE REGION THURSDAY
NIGHT AND MOSTLY SUNNY SKIES ON FRIDAY. HIGH PRESSURE WILL SLIDE
EAST ON SATURDAY AND SUNDAY WITH CONTINUED DRY WEATHER. A FRONT WILL
APPROACH FROM THE WEST SUNDAY NIGHT WITH INCREASING CLOUDS. THE FRONT
WILL SLIDE EAST ACROSS THE REGION MONDAY WITH THE CHANCE FRO
SHOWERS.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: STAYED CLOSE TO VFR INTO TONIGHT. SOME PATCHY FOG COULD
ALLOW FOR BRIEF MVFR/IFR CONDITIONS AT THE AIRFIELDS EARLY
WEDNESDAY MORNING. FOG SHOULD LIFT AND BURN OFF BY 8 AM.
SHORT TERM: MAINLY VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM: NO HEADLINES. SSE SWELL WILL CONTINUE THROUGH THE
PERIOD W/WAVE HEIGHTS OF 2-3 FT AND THIS WILL MAINLY BE AWAY FROM
THE INTRA-COASTAL WATERS. WINDS WILL LIGHT AVERAGING 5-10 KTS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SCA LEVELS THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT/MCB
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
656 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A WEAK COLD FRONTAL WILL CROSS THE STATE TODAY INTO TONIGHT WITH
SOME SHOWERS POSSIBLE. ANOTHER WEAK DISTURBANCE WILL MOVE ACROSS THE
REGION ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...ADJUSTED THE SKY AND TEMPERATURES TO MATCH THE INITIAL
CONDITIONS. SATL IMAGERY SHOWING CLOUDS STREAMING NE ACROSS THE
STATE. RADAR HAD A LINE OF HEAVIER ECHOES(30DBZ) MOVING E. DID AN
AREAL ADJUSTMENT ON THE POPS TO ACCOUNT FOR WHAT THE RADAR WAS
INDICATING.
PREVIOUS DISCUSSION...
MAIN CHALLENGE THIS TERM WILL BE SHOWER ACTIVITY AND QPF.
LATEST RADAR SHOWED ACTIVITY MOVING INTO WNW MAINE THIS MORNING W/ECHOES
UP TO 30DBZ WHICH LEADS TO THE POTENTIAL FOR SOME SHOWER ACTIVITY
TO REACH THE GROUND. SATL IMAGERY & CEILING PLOTS INDICATED CLOUD
DECKS OF 7K-10K FT. THIS IS REFLECTED IN THE UPPER AIR ANALYSIS.
THE LATEST NAM AND GFS HAVE INITIALIZED WELL W/THE LATEST RADAR
IMAGERY. HRRR INITIALIZED WELL BUT SEEMS TO BE OVERDONE W/ITS
RAINFALL OVERSPREADING THE CWA BY LATE MORNING INTO THE AFTERNOON.
MID LEVEL FORCING ALONG W/LLVL CONVERGENCE ALONG AND JUST AHEAD OF
THE FRONTAL BOUNDARY WILL ALLOW FOR SHOWERS TODAY. ATTM, USED A
BLEND OF THE NAM12 AND GFS FOR THE POPS WHICH SHOW 20-40% ACROSS
THE CWA EXCEPT THE COAST. HPC QPF LOOKS OVERDONE AND TOO FAR
SOUTH. THEREFORE, DECIDED TO BLEND THE NAM12/HPC AND SREF FOR QPF
WHICH SHOWS NO MORE THAN .10 OF AN INCH AND THIS WILL BE MAINLY
ACROSS THE CENTRAL AND EASTERN AREAS. STAYED CLOSE W/THE DAYCREW`S
MAXES FOR TODAY W/MID 70S NORTH AND UPPER 70S TO AROUND 80 FOR THE
CENTRAL AND DOWNEAST AREAS. ANOTHER FACTOR TODAY WILL BE WINDS AND
MDL SOUNDINGS INDICATE AN INVERTED V-SOUNDING WHICH SUPPORTS SOME
WIND TO POSSIBLY MIX DOWN. DECIDED TO BOOST WIND GUSTS TO 20 MPH
MAINLY ACROSS THE HIGHER TERRAIN AND OPEN AREAS.
TONIGHT WILL SEE CLOUDS BEGINNING TO BREAK UP AS THE FRONT SLOWLY
SLIDES TO THE EAST. SOME CAA IS SEEN BEHIND THE FRONT AND W/WINDS
BECOMING LIGHT AND A WET GROUND, THINKING HERE IS THAT SOME FOG
WILL FORM. BUFKIT PROFILES SUPPORT THIS THINKING. MID LEVEL MOISTURE
IS SHOWN BY THE GFS AND NAM TO MOVE ACROSS NORTHERN AREAS OVERNIGHT.
THIS COULD HALT FURTHER PROGRESSION OF THE FOG. ADDED FOG TO THE
FORECAST BUT NOT CONFIDENT TO GO ANY MORE THAN USING PATCHY
WORDING. DAYCREW CAN ASSESS THIS FURTHER. TEMPERATURES WILL BE
COOL W/MINS DROPPING BACK INTO THE MID AND UPPER 40S ACROSS THE
NORTH AND WEST AND LOW TO MID 50S FOR THE CENTRAL AND DOWNEAST REGIONS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN TO OUR SOUTH ON WEDNESDAY AS LOW
PRESSURE MOVES EAST ACROSS ONTARIO/QUEBEC PROVINCE. THIS WILL KEEP
A SOUTHWEST FLOW AND WEAK WARM ADVECTION ACROSS THE REGION ON
WEDNESDAY WITH PARTLY/MOSTLY SUNNY SKIES. HIGHS ON WEDNESDAY WILL
RANGE FROM THE LOW/MID 70S NORTH AND UPPER 70S TO NEAR 80
DOWNEAST. A DRY NIGHT CAN BE EXPECTED WEDNESDAY NIGHT AS LOW
PRESSURE CONTINUES TO SLIDE TO OUR NORTH. LOWS WEDNESDAY NIGHT
WILL RANGE FROM THE LOW TO MID 50S. A COLD FRONT WILL SLIDE ACROSS
THE REGION ON THURSDAY. SB CAPES ARE UNIMPRESSIVE SO WILL NOT
INCLUDE THE MENTION OF THUNDER BUT WILL MENTION THE CHANCE FOR
AFTERNOON SHOWERS MAINLY ACROSS NORTHERN AND CENTRAL AREAS. HIGH
ON THURSDAY WILL RANGE FROM THE MID TO UPPER 70S NORTH AND LOW TO
MID 80S DOWNEAST...BUT IT WILL BE COOLER NEAR THE COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THURSDAY NIGHT AND
FRIDAY. THIS WILL BRING MAINLY CLEAR SKIES TO THE REGION THURSDAY
NIGHT AND MOSTLY SUNNY SKIES ON FRIDAY. HIGH PRESSURE WILL SLIDE
EAST ON SATURDAY AND SUNDAY WITH CONTINUED DRY WEATHER. A FRONT WILL
APPROACH FROM THE WEST SUNDAY NIGHT WITH INCREASING CLOUDS. THE FRONT
WILL SLIDE EAST ACROSS THE REGION MONDAY WITH THE CHANCE FRO
SHOWERS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: STAYED CLOSE TO VFR INTO TONIGHT. SOME PATCHY FOG COULD
ALLOW FOR BRIEF MVFR/IFR CONDITIONS AT THE AIRFIELDS EARLY
WEDNESDAY MORNING. FOG SHOULD LIFT AND BURN OFF BY 8 AM.
SHORT TERM: MAINLY VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM: NO HEADLINES. SSE SWELL WILL CONTINUE THROUGH THE
PERIOD W/WAVE HEIGHTS OF 2-3 FT AND THIS WILL MAINLY BE AWAY FROM
THE INTRA-COASTAL WATERS. WINDS WILL LIGHT AVERAGING 5-10 KTS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SCA LEVELS THROUGH THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT TUE AUG 21 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EDT TUE AUG 21 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THAT THE DEEP TROF THAT
HAS DOMINATED THE ERN CONUS FOR SEVERAL DAYS IS IN THE PROCESS OF
DEAMPLIFYING AND LIFTING OUT. SHORTWAVE THAT DROPPED THRU THE UPPER
LAKES YESTERDAY AND GENERATED SCT SHRA IS HEADING FOR THE UPPER OHIO
VALLEY. TO THE N...A SHORTWAVE IS MOVING SE THRU NRN MANITOBA TOWARD
NRN ONTARIO. IN RESPONSE...ZONE OF WAA IS SPREADING E ACROSS NRN
ONTARIO EARLY THIS MORNING. SOME CI IS PEELING S TOWARD THE UPPER
LAKES...BUT WAA MID CLOUDS AND ANY SHRA ARE STILL WELL N OF THE FCST
AREA. MAINLY CLEAR SKIES ACROSS THE FCST AREA AND LITTLE/NO WIND
COMBINED WITH THE MOISTURE FROM YESTERDAYS SHRA HAS LED TO RECENT
DEVELOPMENT OF SHALLOW PATCHY FOG AS A NUMBER OF OBS ARE SHOWING
WIDELY FLUCTUATING VIS.
MAIN FCST CONCERN IN THE SHORT TERM IS POTENTIAL OF CONVECTION
TONIGHT AS TRAILING SFC COLD FRONT FROM AFOREMENTIONED SHORTWAVE
SAGS S TOWARD THE UPPER LAKES. TODAY WILL BE A DRY DAY AS MAIN PUSH
OF WAA CONTINUES TO BE EASTWARD ACROSS NRN ONTARIO AHEAD OF
SHORTWAVE DROPPING SE INTO NRN ONTARIO. UNDER MOSTLY SUNNY
SKIES...MIXING UPWARDS OF 800MB OR SO ON FCST SOUNDINGS YIELDS MAX
TEMPS MAINLY IN THE MID/UPPER 70S. SOME LOCAL COOLING WILL OCCUR
NEAR THE GREAT LAKES.
TONIGHT...850MB THERMAL RIDGE AND MAIN ZONE OF WAA SINKS S INTO THE
UPPER LAKES. AXIS OF MODEST WRLY LOW-LEVEL JET OF 20-30KT REMAINS
MOSTLY JUST N OF UPPER MI...BUT PROXIMITY IS PROBABLY CLOSE ENOUGH
TO WARRANT A SLIGHT CHC OF SHRA/TSRA OVER THE KEWEENAW LATE TONIGHT.
CHC POPS WERE UTILIZED TO THE N ACROSS LAKE SUPERIOR. PER FCST
SOUNDINGS...LOW-LEVELS REMAIN DRY WITH MOISTURE CONFINED TO ROUGHLY
ABOVE 750MB. MIGHT BE ABLE TO GET 100-200J/KG OF CAPE FOR PARCELS
LIFTED FROM THE ELEVATED MOIST LAYER. GIVEN THE LACK OF
INSTABILITY...THE ELEVATED CONVECTION MAY HAVE TROUBLE PRODUCING
PCPN THAT WILL REACH THE GROUND. WITH S/SW WINDS STIRRING IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...TEMPS THERE MAY NOT FALL BLO
60F TONIGHT. EXPECT 50S ELSEWHERE. SHOULD BE ENOUGH DECOUPLING FOR
MINS DOWN TO AROUND 50F IN THE TRADITIONAL COLD SPOTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 450 AM EDT TUE AUG 21 2012
LARGE SCALE PATTERN FEATURES TROUGH OVER GREAT LAKES CONTINUING TO
BREAK DOWN INTO MORE ZONAL FLOW PATTERN BY LATE THIS WEEK. THIS
ALLOWS SHORTWAVE TROUGH EMERGING FROM TROUGH AXIS FROM GULF OF
ALASKA TO PACIFIC NORTHWEST TO PROPEL EAST INTO NORTHERN PLAINS
AND UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. AHEAD OF THE NORTHERN
PLAINS SHORTWAVE...SURFACE TROUGH OVER NORTHERN ONTARIO WILL DROP
INTO UPPER GREAT LAKES ON WEDNESDAY AND BECOME FAIRLY STATIONARY OVER
UPPER MICHIGAN THROUGH FRIDAY. COULD SEE AT LEAST A COUPLE INTERVALS
OF SHRA/TSRA THURSDAY INTO FRIDAY AS THE LARGER SCALE UPPER TROUGH
INTERACTS WITH THE SURFACE TROUGH.
MAJORITY OF MOISTURE ALONG AND AHEAD OF SURFACE TROUGH ON WEDNESDAY
IS H7-H5 WITH LIFT ACTING ON THIS LAYER OF MOISTURE. VERY LITTLE
MOISTURE IS PRESENT BLO H7...SO FOR WEDNESDAY HAVE KEPT POPS TIED
INTO THE AREA OF H7-H5 MOISTURE/UVM AND H7 MOISTURE ADVECTION.
STRONGEST PVA FM SHORTWAVE TRACKING ACROSS ONTARIO STAYS WELL TO THE
NORTH AND EAST OF UPR MICHIGAN...AS DOES DIVERGENCE ALOFT FM JET
STREAK PASSING JUST SOUTH OF JAMES BAY. OVERALL THERE IS NOT A LOT OF
FORCING TO JUSTIFY POPS OVER MOST OF CWA. KEPT SOME POPS IN THE EAST
CWA...BUT REMOVED POPS OVER THE CENTRAL CWA. GIVEN EXPECTED THINNING
MID CLOUDS BY AFTERNOON SHOULD SEE TEMPS WARM NICELY WITH STRONGER
1000-850MB SW WINDS PRESENT JUST AHEAD OF BOUNDARY DROPPING INTO
UPPER GREAT LAKES. NAM/GFS SOUNDINGS POINT TO MIXING UP TO 850-800MB.
MIXING TO H85 YIELDS RETURN TO THE 80S FOR MUCH OF THE AREA...BOOSTED
FURTHER BY MINIMAL LAKE BREEZES AS STRONGER 950-925MB SW WINDS HOLD
THROUGH THE AFTN. WITH ENOUGH SUNSHINE...IT IS LIKELY THAT SOME
AREAS OF CWA SEE TEMPS INTO THE MIDDLE 80S. MINIMUM IN PRECIP CHANCE
CONTINUES THROUGH MOST OF WEDNESDAY NIGHT AND MAYBE INTO THURSDAY
MORNING AS WELL AS MAIN FOCUS FOR SHRA/TSRA WILL BE TIED INTO LEAD
SHORTWAVE PUSHING INTO MINNESOTA BY 12Z THURSDAY OUT AHEAD OF H85-H5
TROUGH MOVING ACROSS THE NORTHERN PLAINS.
CHANCES FOR SHRA/TSRA INCREASE BY THURSDAY AFTERNOON AS THE LEAD
SHORTWAVE PRESSES INTO UPPER GREAT LAKES AND INTERACTS WITH
TEMPERATURE AND MOISTURE ADVECTION INTO SURFACE BOUNDARY PRESENT
OVER THE AREA. MAX H85 MOSITURE ADVECTION AND PVA FROM THE WAVE
COINCIDE OVER WEST HALF OF UPR MICHIGAN ON THURSDAY. INCREASED POPS
OVER THE WEST BUT ALSO WENT WITH SLIGHT CHANCE FOR ALL AREAS DUE TO
THE LOW-LEVEL TROUGH IN THE VICINITY. SHOWED WARMEST TEMPS ON
THURSDAY OVER THE EAST AS THERE IS HIGHER PROBABILITY IT REMAINS
MOSTLY SUNNY THERE INTO THE EARLY-MID AFTERNOON. TEMPS WILL RANGE
FROM THE MID 70S AT THE COOLEST AND WITH ENOUGH SUNSHINE MAY BUMP
INTO THE MID 80S OVER THE EAST. SEEMS THAT BETTER CHANCES OF
SHRA/TSRA THURSDAY NIGHT SET UP MORE OVR LK SUPERIOR ON NOSE OF H85
JET AND CLOSER TO TRACK OF LEAD SHORTWAVE LIFTING INTO ONTARIO.
CANNOT RULE OUT CHANCES ANYWHERE THOUGH AS AGAIN...THE SURFACE FRONT
IS STILL FORECAST CLOSE TO UPR MICHIGAN. INTO FRIDAY...BEFORE IT
LOOKED LIKE THIS WOULD BE THE DAY OF GREATEST RAIN CHANCES. NOT SO
CLEAR CUT NOW THOUGH...AND UNFORTUNATELY THIS FORECAST UNCERTAINTY
PERSISTS RIGHT THROUGH THE UPCOMING WEEKEND AS WELL. STILL PREFER TO
HOLD ONTO THE IDEA FM THE ECMWF AND GEM-NHEM WITH ANOTHER BOUT OF
H85 MOISTURE ADVECTION KICKING OFF SHRA/TSRA ALONG H5 TROUGH AXIS
OVR UPR MICHIGAN DURING PEAK HEATING. STRONGEST HEIGHT FALLS THEN
SHIFT TO THE NORTH AND EAST OF CWA FRIDAY NIGHT SO EXPECT GREATEST
RAIN CHANCES TO PROBABLY DO SO AS WELL.
CURRENT FORECAST FOR SATURDAY AND SUNDAY FEATURES CHANCES FOR
SHRA/TSRA BUT MODEL TRENDS NOW SUGGEST IT MAY END UP BEING MOSTLY
FREE OF RAIN...AT LEAST SATURDAY AND SATURDAY NIGHT. ONLY MODEL THAT
HITS POPS UP THIS WEEKEND IS THE GFS...BUT SINCE GFS SOLUTION
CONTINUES TO BE INFLUENCED BY CONVECTIVE FEEDBACK...HPC HAS TOSSED
IT OUT FOR THIS FORECAST CYCLE. BASED ON POSITION OF INCOMING UPPER
TROUGH OVR SCNTRL CANADA...UPPER JET...SFC FRONT AND H85-H7 MOISTURE
ADVECTION...BETTER SHRA/TSRA CHANCES WOULD SEEM TO SPLIT MORE AROUND
UPR MICHIGAN THROUGH THE WEEKEND. LATER FORECASTS MAY NEED TO TREND
DRIER. LACK OF CLOUDS/SHRA/TSRA WOULD LEAD TO WARMER TEMPS AS WELL
SINCE H85 TEMPS ARE A WARM 15-18C AND LOW-LEVEL WINDS ARE SOUTHWEST
AHEAD OF LARGER SCALE TROUGH. CURRENT FORECAST POINTS TO UPPER
70S-LOWER 80S WITH MOSTLY CLOUDY SKIES AND A CHANCE FOR RAIN. WHEN
IN REALITY IT VERY WELL COULD END UP MOSTLY SUNNY WITH HIGHS IN THE
MID-UPPER 80S. BY LATE SUNDAY...BETTER CHANCES OF SHRA/TSRA PRESS
ACROSS CWA WITH COLD FRONT TIED TO UPPER TROUGH MOVING FM MANITOBA
INTO ONTARIO. EXACT TIMING WITH THIS FRONT WILL REMAIN A QUESTION
UNTIL WE GET CLOSER TO THE WEEKEND THOUGH...SO KEPT WITH CONSENSUS
APPROACH FOR POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 740 AM EDT TUE AUG 21 2012
WITH RELATIVELY DRY LOW-LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THIS FCST PERIOD AT KIWD/KCMX/KSAW. MODEST LOW-LEVEL JET ARRIVING
OVERNIGHT TONIGHT WILL LEAD TO POSSIBLE LLWS...MAINLY AT KCMX WHICH
WILL BE CLOSER TO AXIS OF SPEED MAX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EDT TUE AUG 21 2012
LIGHTER WINDS BECOMING WEST SOUTHWEST AND INCREASE TO 15-25 KTS
LATER TODAY INTO TONIGHT AS FRONT DROPPING IN FROM ONTARIO TIGHTENS
PRESSURE GRADIENT. STRONGEST WINDS WILL OCCUR OVER WEST AND NORTH
CENTRAL LK SUPERIOR BETWEEN ISLE ROYALE AND TIP OF KEWEENAW. WINDS
RELAX ON WEDNESDAY AS PRESSURE GRADIENT SLACKENS. EXPECT WINDS TO
INCREASE AGAIN FOR THE UPCOMING WEEKEND AS STRONGER LOW PRESSURE
SYSTEM AND FRONT APPROACH FROM THE PLAINS. COULD SEE SOUTHERLY
GUSTS TO 25 KTS OVER EASTERN SECTIONS SATURDAY NIGHT INTO SUNDAY
JUST AHEAD OF THE FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
619 AM CDT TUE AUG 21 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
ONE MORE FINE WEATHER DAY IN STORE ACROSS THE REGION TODAY AS HIGH
PRESSURE SLIPS SLOWLY SOUTHEAST. THE LOW LEVEL FLOW WILL BEGIN TO
INCREASE FROM THE SOUTHWEST TONIGHT...WITH RATHER STRONG THETA-E
ADVECTION DEVELOPING ACROSS SOUTHWEST MN AFTER MIDNIGHT. THE NAM
310K THETA SURFACE HAS PLENTY OF UPGLIDE DEVELOPING AS WELL. THIS
COMBINED WITH MID LEVEL INSTABILITY SHOULD YIELD SOME SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS THE FAR SOUTH. THE ACTIVITY MAY
GRAZE THE METRO AREA LATE WEDNESDAY MORNING WITH A CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS WEST CENTRAL WI WEDNESDAY
AFTERNOON AND EVENING. HIGHS TODAY WILL GENERALLY BE IN THE
LOWER 80S WITH HIGHS CLIMBING INTO THE MIDDLE TO UPPER 80S ON
WEDNESDAY. THE WARMEST READINGS ON WEDNESDAY WILL BE ALONG AND
SOUTH OF THE MN RIVER.
THE UPPER AIR PATTERN WILL CHANGE FROM NORTHERLY TO WESTERLY OVER
THE NEXT 24 HOURS. THIS WILL ALLOW A SERIES OF SHORT WAVES TO
IMPACT THE REGION. THE FIRST WILL BE LATE WEDNESDAY NIGHT AND
THURSDAY...AIDING IN MORE WIDESPREAD SHOWERS AND THUNDERSTORMS.
THE WESTERN HALF OF THE FA LOOKS MOST FAVORABLE FOR RAIN ON
THURSDAY WITH THE EASTERN HALF THURSDAY NIGHT. THE TIMING ON THIS
FEATURE REMAINS CONSISTENT WITH THE VARIOUS SOLUTIONS.
A SECOND WAVE FOR THE WEEKEND HAS LESS AGREEMENT WITH THE ECMWF
DEEPER AND SLOWER ALOFT. WHAT WOULD BE MAINLY A CHANCE OF SHOWERS
AND THUNDERSTORMS ON SATURDAY ON THE GFS TURNS INTO A PROLONGED
EVENT THAT COULD LAST INTO MONDAY OVER EASTERN AREAS ON THE ECMWF.
THE TWO SOLUTIONS MAY REPRESENT THE EXTREMES WITH THE GEM NOT AS
FAST AS THE GFS BUT NOT AS DEEP AND SLOW AS THE ECMWF. THIS
SOLUTION WOULD FAVOR LESS PRECIPITATION OVER THE WESTERN FA ON
SUNDAY WITH DIMINISHING POPS EAST SUNDAY NIGHT. COLLABORATION
YIELDED A DRY FORECAST FOR MONDAY. HIGHS DURING THE WEEKEND WILL
SLIP BACK TO NEAR NORMAL VALUES.
ON A SIDE NOTE...MSP IS RUNNING A 1.8 DEGREES BELOW NORMAL FOR THE
MONTH. WE HAVE NOT HAD A BELOW NORMAL MONTH SINCE MAY 2011. IT
LOOKS AS THOUGH MANY OF THE DAYS LEFT IN AUGUST WILL BE AT OR
ABOVE NORMAL...BUT WILL IT BE ENOUGH?
&&
.AVIATION.../12Z TAF ISSUANCE/
HIGH PRESSURE WILL BE SLIDING SE OF THE MPX AREA TODAY...WITH 5-10
KT SW WINDS SETTING UP AS A RESULT. COMPARING KMPX VAD WIND DATA
WITH MODEL SOUNDINGS...THE RAP LOOKS TO BE VERIFYING BEST THIS
MORNING WITH DIRECTIONS...SO FOLLOWED IT FOR DIRECTIONS
TODAY. THIS RESULTED IN DIRECTIONS WITH A BIT MORE OF A WEST
COMPONENT THAN WHAT LAMP HAS. TOWARD 12Z WED A WARM FRONT WILL
BEGIN LIFTING NORTH TOWARD SW MN. BULK OF CLOUD COVER AND ANY
PRECIP AHEAD OF IT LOOK TO COME IN JUST AFTER THIS TAF
PERIOD...BUT WILL LIKELY START TO SEE AN INCREASE IN MID CLOUDS
TOWARD THE END OF THE RWF/MSP TAF PERIODS.
KMSP...FEW CONCERNS AGAIN TODAY WITH HIGH PRESSURE STILL IN
CONTROL. LOOKING AT MPX VAD WINDS...MAY HAVE A FEW OBS THIS
MORNING CLOSER TO 270 IN DIRECTION BEFORE TRENDING TOWARD 220 THIS
AFTERNOON. VFR CONDS CAN BE EXPECTED THROUGHOUT. WINDS WILL BE
STAYING UP AROUND 5 KTS TONIGHT...SO RIVER VALLEY FOG CONCERNS
WILL BE LOW.
/OUTLOOK FOR KMSP/
.WEDNESDAY...VFR. A FEW AFTERNOON TSRA POSSIBLE. WIND SSE 10 KTS
.THURSDAY...VFR. TSRA CHANCES INCREASING IN THE EVENING. WIND S 10 KTS
.FRIDAY...VFR. TSRA CHANCES DIMINISHING IN MORNING. WIND SW 10 KTS
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/MPG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
645 AM EDT TUE AUG 21 2012
.SYNOPSIS...
A RATHER POTENT MID LEVEL SHORT WAVE AND A WEAK SURFACE TROUGH
WILL COMBINE TO PRODUCE A CHANCE OF SHOWERS AND THUNDERSTORMS
TODAY. THEREAFTER...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
BRING WARM AND DRY WEATHER FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE DEVELOPED FROM CINCINNATI THROUGH LIMA EARLY THIS
MORNING AHEAD OF A RATHER SHARP SHORT WAVE TROUGH. EXPECT SHOWERS
AND A FEW THUNDERSTORMS TO EXPAND EASTWARD INTO THIS AFTERNOON
AIDED BY INCREASING INSTABILITY DUE TO DAYTIME HEATING. THE TROUGH
AND ASSOCIATED MOISTURE WILL BE MOVING EAST OF THE AREA BY LATE
AFTERNOON...WHICH WILL BRING AN END TO THE PRECIPITATION. THE CHANCE
FOR SEVERE THUNDERSTORMS APPEARS LOW DUE TO WEAK INSTABILITY AND
WIND FIELDS ACCOMPANYING THE SHORT WAVE. TEMPERATURES WILL TOP OUT
AROUND 80 THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
SKIES WILL CLEAR TONIGHT AS THE SHORT WAVE MOVES WELL EAST OF THE
REGION AND HIGH PRESSURE STARTS TO BUILD AT ALL LEVELS OF THE
ATMOSPHERE. THE HIGH WILL BE ANCHORED TO THE EAST THROUGH
THURSDAY...WHILE 500 MB HEIGHTS INCREASE TO ABOVE 5900 METERS.
THIS WILL RESULT IN A PERIOD OF PERSISTENTLY DRY WEATHER...AND
GRADUALLY INCREASING TEMPERATURES. UNDER MOSTLY SUNNY SKIES AND
MODERATE WARM ADVECTION...HIGHS ON WEDNESDAY WILL BE IN THE LOWER
TO MIDDLE 80S...RISING TO THE MIDDLE AND UPPER 80S ON THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
SLOWLY BUILDING UPPER HEIGHTS ALONG WITH SOUTHERLY FLOW ON THE BACK
SIDE OF A SURFACE HIGH WILL RESULT IN ABOVE NORMAL TEMPERATURES AND
DRY CONDITIONS THROUGH THE PERIOD. THERE IS SOME POSSIBILITY THAT A
WEAK BOUNDARY COULD APPROACH THE NORTHWEST COUNTIES EARLY NEXT WEEK.
BUT CHANCE OF RAIN REMAINS QUITE LOW AT THIS POINT.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
MID LEVEL S/W ENERGY PUSHING INTO OHIO HAS SET OFF A FEW SHOWERS
WHICH ARE MOVING ACROSS WESTERN OHIO. LATEST HRRR RUN CONTINUES TO
HAVE A HANDLE ON THESE SHOWERS...WHICH ARE EXPECTED TO LIFT NE AND
CONTINUE TO WEAKEN THIS MORNING. MOST OF THIS SHOWER ACTIVITY WILL
MISS THE TAF SITES WITH ONLY MID LEVEL CIGS EARLY.
AS THE ASSOCIATED LOW LEVEL TROUGH AXIS TRACKS EAST THROUGH THE
DAY...EXPECT ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM DEVELOPMENT
AS THE AIRMASS DESTABILIZES THROUGH THE AFTERNOON HOURS. EXACT
LOCATION OF ANY INITIATION REMAINS SOMEWHAT UNCERTAIN. HAVE CONTINUED
A MENTION OF VCSH IN ALL TAFS THIS AFTN. HAVE LIMITED THE WEST TO
EARLY AFTN AND LINGERED CHC IN THE EAST THRU 22Z. INSTBY IS
MARGINAL WITH THE BEST THREAT FOR THUNDER OVER THE EAST. DUE TO
LIMITED INSTBY HAVE ONLY THE MENTION OF VCSH AT THIS TIME. WITH
THE PASSAGE OF THE TROF AXIS THE THREAT OF PRECIPITATION WILL END
BY EVENING. DUE TO LIGHT WINDS AND GOOD LO LEVEL MSTR FOG
DEVELOPMENT IS LKLY TONIGHT. HAVE AN MVFR VSBY RESTRICTION
MENTIONED AT ALL TAF SITES.
.OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS MIAMI FL
209 PM EDT TUE AUG 21 2012
.DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE INTERIOR AND PUSH TOWARDS THE NORTHEAST SECTIONS OF THE CWA THIS
AFTERNOON AND INTO THE EVENING UNDER THE SOUTHWEST FLOW ALOFT. A
FEW STORMS COULD BE STRONG...WITH THE MAIN THREAT BEING STRONG
WINDS OF 40 TO 50 MPH. THE HRRR IS SHOWING THAT A LINE OF STORMS
MAY MOVE ACROSS THE EASTERN GULF AND INTO CENTRAL FLORIDA...WITH
THE TAIL END OF THIS LINE OF SHOWERS AND THUNDERSTORMS POSSIBLY
MOVING INTO THE LOCAL GULF WATERS AND PORTIONS OF THE NORTHWEST
AFTER 00Z. THIS IS CONSISTENT WITH THE 12Z GFS SHOWING A PIECE OF
ENERGY ROTATING AROUND THE BASE OF THE TROUGH AND ACROSS CENTRAL
FLORIDA OVERNIGHT. SO WILL KEEP 20-30 POPS FOR THIS REGION.
THE UPPER TROUGH ALONG THE EASTERN SEABOARD WILL BEGIN TO FILL AND
LIFT TO THE NORTHEAST TONIGHT AND WEDNESDAY...BUT A WEAKNESS WILL
REMAIN OVER THE GULF AND THE WESTERN ATLANTIC THROUGH THE WEEKEND.
AT THE SURFACE...THE QUASI-STATIONARY FRONT OVER NORTH FLORIDA
WILL SLOWLY DRIFT SOUTHWARD TONIGHT INTO WEDNESDAY AND THEN BEGIN
TO WASH OUT AND DRIFT NORTHWARD INTO THURSDAY. THE SUBTROPICAL
RIDGE OVER THE WESTERN ATLANTIC WILL MOVE NORTHWARD AND THE DRY
AIR AND HAZE OVER THE BAHAMAS IS EXPECTED TO PUSH INTO SOUTH
FLORIDA ON WEDNESDAY AND THURSDAY. IN ADDITION...THE LOW/MID LEVEL
FLOW WILL SHIFT FROM THE SOUTHWEST TO THE EAST AND SOUTHEAST BY
THURSDAY.
WITH PWATS FALLING TO AROUND 1.5 INCHES ON WEDNESDAY ALONG THE
SOUTHEAST COAST...ONLY MINIMAL RAIN CHANCES ARE EXPECTED.
STEERING FLOW WILL PUSH STORMS SLOWLY TO THE NORTH ON WEDNESDAY.
HIGHER MOISTURE WILL ALSO LINGER AROUND THE LAKE ON WEDNESDAY...SO
THERE WILL STILL BE A CHANCE OF STORMS FOR THE LAKE OKEECHOBEE
REGION. MODEL SOUNDINGS ARE SHOWING RELATIVELY STEEP LAPSE RATES
ABOVE THE INVERSION AND STRONG STORMS AND POSSIBLY AN ISOLATED
SEVERE STORM CANNOT BE RULED OUT ON WEDNESDAY. HEAT INDICES WILL
BE THE TYPICAL 100-108F FOR THIS TIME OF YEAR...WITH THE HIGHEST
READINGS ACROSS THE INTERIOR.
EVEN DRIER AIR IS EXPECTED TO MOVE INTO THE REGION ON
THURSDAY...WITH PWATS ACROSS THE REGION DROPPING TO 1.3-1.6 INCHES.
WITH THE FLOW SHIFTING TO THE EAST AND SOUTHEAST...EXPECT THE EAST
COAST TO MAINLY STAY DRY...WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE INTERIOR AND TOWARDS THE GULF COAST.
FOR FRIDAY INTO SATURDAY...THE PRESSURE GRADIENT MAY BEGIN TO
TIGHTEN AS TROPICAL DEPRESSION NINE MOVES NEAR HAITI AND EASTERN
CUBA. SO SOMEWHAT BREEZIER EASTERLY FLOW COULD BEGIN ON FRIDAY AND
SATURDAY WITH AN INCREASE IN LOW LEVEL MOISTURE AND RAIN CHANCES.
IT IS STILL TOO EARLY TO DETERMINE THE IMPACTS OF TROPICAL
DEPRESSION NINE ON SOUTH FLORIDA OR THE SURROUNDING MARINE AREAS IN
THE LONG TERM. HOWEVER...THERE IS INCREASING POTENTIAL THAT SOUTH
FLORIDA AND/OR THE SURROUNDING MARINE AREAS COULD BE IMPACTED LATE
THIS WEEKEND INTO EARLY NEXT WEEK. SO NOW IS A GOOD TIME TO
REVIEW INDIVIDUAL TROPICAL CYCLONE PREPAREDNESS PLANS. FOR THE
LATEST INFORMATION REGARDING TROPICAL DEPRESSION NINE...CONTINUE
TO MONITOR THE LATEST FORECASTS FROM THE NATIONAL HURRICANE
CENTER.
&&
.AVIATION...
A FEW THUNDERSTORMS COULD DEVELOP THIS AFTERNOON
MAINLY TOWARD KPBI AND KFXE, BUT EXPECT TO HAVE ACTIVITY CLOSE
ENOUGH TO THE REST OF THE ERN TERMINALS TO BE WORTH MENTIONING
VCTS IN TAFS. WL EXPECT ANY SHWR/TSTM TO REMAIN WELL AWAY FROM
KAPF AND NO AFFECT OPERATIONS. EVENING ACTIVITY SHOULD TAPER OFF
BY 00Z TONIGHT. SFC SHOULD REMAIN MOSTLY SE, ALTHOUGH BECOMING
LIGHT AND VARIABLE AFTER 00Z AND INCREASING AGAIN TO AROUND 8-10
KTS AFTER 13Z WEDNESDAY.
&&
.MARINE...
A RIDGE OF HIGH PRESSURE WILL BE LOCATED OVER THE SOUTH FLORIDA
WATERS THROUGH THE MIDDLE OF THE WEEK BEFORE SHIFTING NORTH DURING
THE LATTER PART OF THE WEEK. THIS WILL LEAD TO WINDS OUT OF THE
SOUTH BECOMING EASTERLY LATE IN THE WEEK. THE PRESSURE GRADIENT IS
EXPECTED TO INCREASE FRIDAY AND SATURDAY AS TROPICAL DEPRESSION
NINE MOVES NEAR HAITI AND EASTERN CUBA. THE FORECAST FOR LATE THIS
WEEKEND BECOMES HIGHLY DEPENDENT ON THE EVOLUTION THIS TROPICAL
CYCLONE. THE FORECAST TRACK OF THIS POTENTIAL SYSTEM IS IN THE
GENERAL DIRECTION OF THE REGIONAL WATERS AND SHOULD BE CLOSELY
MONITORED BY ALL MARINE INTERESTS OVER THE COMING DAYS.
&&
.FIRE WEATHER...
SOUTH TO SOUTHWEST WINDS WILL BE OVER SOUTH FLORIDA AGAIN ON
WEDNESDAY AS A HIGH PRESSURE RIDGE PERSISTS JUST SOUTH OF THE
AREA OVER THE KEYS AND FLORIDA STRAITS. ISOLATED TO SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AFTERNOON ON
WEDNESDAY BUT AFFECTING MAINLY THE INTERIOR AND THE LAKE
OKEECHOBEE REGION AS THE ACTIVITY WILL MOVE TO THE NORTHEAST. EAST
AND WEST COAST SEA BREEZES ARE EXPECTED TO DEVELOP LATE THIS
MORNING AND CONTINUE INTO THIS AFTERNOON ON WEDNESDAY. FLOW WILL
BECOME MORE EASTERLY ON THURSDAY AND STRENGTHEN FRIDAY INTO THE
WEEKEND AS THE PRESSURE GRADIENT INCREASES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 91 78 89 / 30 20 10 10
FORT LAUDERDALE 80 91 80 91 / 20 20 10 10
MIAMI 79 92 79 91 / 20 10 10 10
NAPLES 77 93 77 93 / 30 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...47/RGH
EXTENDED FORECAST DISCUSSION AND CENTRAL REGION INITIALIZATION WITH
POPS ACROSS OUR WEST BY SUNDAY AND BEST CHANCES SUNDAY NIGHT AND
MONDAY. OTHERWISE...WILL NOT MAKE ANY CHANGES TO TEMPERATURES. HIGH
PRESSURE ACROSS THE EASTERN STATES WILL ALLOW RETURN FLOW WHICH
SHOULD BRING TEMPERATURES BACK UP TO NORMAL OR SLIGHTLY ABOVE NORMAL
IN THE 80S AT LEAST UNTIL FRONTAL PASSAGE MONDAY OR TUESDAY.
&&
.AVIATION /DISCUSSION FOR 220000Z TAFS/...
ISSUED AT 620 PM EDT TUE AUG 21 2012
MVFR FOG IS EXPECTED AT ALL BUT KIND FOR A FEW HOURS
OVERNIGHT...OTHERWISE VFR CONDITIONS EXPECTED.
DIURNAL CU SHOULD BE ABOUT GONE BY TAF VALID TIME. HIGH PRESSURE
WILL BUILD IN DURING THE NIGHT. GROUND HAS DRIED OUT SOME...AND
DRIER AIR IS MOVING IN AS WELL. THUS DO NOT THINK FOG WILL BE AS BAD
AT KLAF AS THE PREVIOUS NIGHT. WILL GO PREDOMINANT MVFR FOR SEVERAL
HOURS THERE.
AT KHUF AND KBMG...AM LESS CONFIDENT IN FOG FORMATION...BUT WILL
KEEP CURRENT FORECAST OF A FEW HOURS OF MVFR FOG THERE. ADDITIONAL
CU WILL FORM WEDNESDAY. WINDS SHOULD REMAIN LESS THAN 10KT THROUGH
THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....MK
AVIATION...50
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
216 PM CDT TUE AUG 21 2012
...UPDATED FOR THE LONG TERM FORECAST...
.SYNOPSIS...
ISSUED AT 900 AM CDT TUE AUG 21 2012
THE 21.12Z 250 HPA RAOB MAP NETWORK SHOWED TWO JETS ACROSS NORTH AMERICA.
ONE AROUND 100 KT WAS LOCATED ACROSS THE PACIFIC NORTHWEST. ANOTHER
ONE THAT WAS FAIRLY STRONG FOR THIS TIME OF YEAR /145 KT/ WAS LOCATED
ACROSS NEW ENGLAND. AT 500 HPA, A SHORTWAVE TROF WAS JUST WEST OF OREGON
AND WASHINGTON. A 590 DM ANTICYCLONE WAS LOCATED OVER THE DESERT SOUTHWEST.
FINALLY, AN ELONGATED TROF EXTENDED FROM CENTRAL QUEBEC TO THE NORTHERN
GULF OF MEXICO. AT 700 HPA, TEMPS WERE IN THE 6 TO 7 DEG C RANGE ACROSS
KANSAS...BASICALLY NOT MUCH CHANGE FROM 24 HOURS AGO. THE IMPRESSIVE
COLD POOL FOR AUGUST WITH VALUES IN THE 0 TO -3 DEG C RANGE WERE LOCATED
ACROSS THE OHIO RIVER VALLEY AND NORTHEAST. AT 850 HPA, LOW DEWPOINT
DEPRESSIONS ACROSS THE TEXAS PANHANDLE WERE ASSOCIATED WITH PRECIP AND
LOW CLOUDS. ACROSS SW KANSAS, THE THERMODYNAMICS WAS FAIRLY WARM AND
DRY. THE WARMEST PLUME WITH TEMPS IN THE LOWER 20S DEG C WAS OBSERVED
ACROSS THE NORTHERN HIGH PLAINS. AT THE SFC, HIGH PRESSURE EXTENDED
ACROSS MUCH OF THE MIDWEST. WEAK RETURN FLOW WAS OBSERVED ACROSS THE
HIGH PLAINS. TROPICAL DEPRESSION NINE WAS LOCATED NEAR 15.2N 51.2W @ 21.09Z.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 100 PM CDT TUE AUG 21 2012
TONIGHT:
THE SHORT TERM METEOROLOGICAL CONCERN IS WHAT TO DO WITH POPS FOR THIS
EVENING. MESOSCALE (NAM, WRF) AND GLOBAL MODELS (GFS, ECMWF) PAINT DOUBT
ON CONVECTIVE PROSPECTS FOR THE EVENING. THIS IS A RESULT OF THE FACT
THAT THE UPPER LEVEL JET/WAVE IS EAST OF THE REGION AND CONVERGENCE
AT THE SURFACE IS FORECAST TO BE WEAK. 850 HPA THETA-E ADVECTION IS
FORECAST TO REMAIN WEAK AS WELL. RECENT HRRR RUNS HAS BEEN INDICATING
ISOLATED ACTIVITY ACROSS THE WESTERN ZONES THIS EVENING BUT THIS MODEL
HAS BEEN TRENDING DOWNWARD OVERALL IN THE LAST SEVERAL RUNS. AS A RESULT,
HAVE REMOVED WX FROM THE GRIDS AND GOING WITH A DRY FORECAST FOR THIS
EVENING. SOUTHERLY WINDS WILL CONTINUE THROUGH THE OVERNIGHT WITH MODERATE
DEWPOINTS AS WELL. LOOK FOR LOWS IN THE LOWER 60S DEG F.
TOMORROW:
THE LEE SURFACE TROUGH WILL STRENGTHEN TOMORROW AS MID TO UPPER LEVEL
FLOW BECOMES A BIT MORE PERPENDICULAR TO THE ROCKIES. I HAVE POPS INCREASING
UP TO THE SLIGHT CATEGORY TOWARDS 00Z TOMORROW EVENING AS WEAK 850 HPA
THETA-E ADVECTION STRENGTHENS AND SOME STORMS COULD FORM NEAR THE LEE
SURFACE TROUGH ACROSS THE W/NW ZONES. OTHERWISE, TOMORROW WILL BE MAINLY
DRY WITH HIGHS IN THE UPPER 80S TO AROUND 90 DEG F. THESE VALUES ARE
VERY CLOSE TO CLIMATOLOGY FOR THIS TIME OF YEAR. TOMORROW WILL BE A
BIT BREEZY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 204 PM CDT TUE AUG 21 2012
THIS WEEK IS SHAPING UP INTO A RELATIVELY WET PATTERN. THE UPPER
LEVEL FLOW IS EVOLVING INTO A MORE PROGRESSIVE PATTERN WITH SHORT
AND LONG WAVES TRAVELING THROUGH THE UPPER PLAINS AND MIDWEST AT A
FAIRLY REGULAR INTERVAL. WE WILL BE ON THE SOUTH END OF MINOR
WAVES, WHICH WILL OVERFLOW AFTERNOON LEE SIDE SURFACE TROUGHS DURING
THE LATE AFTERNOON AND OVERNIGHT PERIODS. THEREFORE, PRECIPITATION
CHANCES WILL BE IN THE RANGE OF 30 PERCENT WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT AS A WEAK LOBE OF VORTICITY SCRAPES WEST TO EAST
THROUGH WESTERN KANSAS. THEN ON EARLY FRIDAY, A STRONGER WAVE UP
NORTH MOVING THROUGH THE DAKOTAS WILL SWING A MORE SIGNIFICANT WAVE
THROUGH KANSAS. DURING THE TIME FROM WEDNESDAY TO FRIDAY, DEW
POINTS WILL BE INCREASING INTO THE MID 60S TO LOWER 70S, ALLOWING
THE POTENTIAL FOR SOME HEAVY RAIN IN OUR SOUTHEAST COUNTIES FRIDAY
NIGHT AND SATURDAY AS THE LOWER LAYER BECOMES MORE SATURATED. THAT
WAVE WILL NOT GO DIRECTLY THROUGH OUR FORECAST AREA, BUT WILL DRAG
SLOWLY THROUGH WESTERN KANSAS ON A NORTHWEST TO SOUTHEAST
ORIENTATION. THIS WILL ALLOW A SURFACE FRONT TO STAY NEARLY
ANCHORED OVER OUR CENTRAL TO SOUTHEASTERN ZONES, AND SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO RE-FIRE ALONG AND SOUTHEAST OF THE
FRONTAL BOUNDARY. POPS WILL BUMP UP INTO THE 40 TO 50 PERCENT
RANGE, FOR SOME OF OUR EASTERN ZONES, WITH 60 PERCENT POPS FRIDAY
NIGHT AND AGAIN SATURDAY NIGHT ACROSS OUR SOUTHEASTERN ZONES,
SOUTHEAST OF A LINE FROM LARNED TO MEADE. DECIDED TO NOT GO AS HIGH
AS THE ECMWF MODEL IS FORECASTING THE QPF TO BE (ABOUT 4 INCHES
TOTAL QPF WED TO SUN) SOUTHEAST OF A PRATT TO ASHLAND LINE, BUT
NEARER THE 2 INCH RANGE, WHICH IS CLOSER TO THE GFS OUTPUT. THE
WAVE WILL BE NEARLY EXITING OUR EASTERN CWA BY SUNDAY, BUT SMALL 20
PERCENT POPS WILL LINGER SUNDAY MORNING ACROSS OUR EXTREME EASTERN
ZONES. AN UPPER LEVEL RIDGE WILL BUILD IN FROM THE SOUTH MONDAY,
AND SHOULD KEEP BOTH MONDAY AND TUESDAY DRY.
MAXIMUM TEMPERATURES WEDNESDAY AND THURSDAY WILL REACH THE NEAR 90F
RANGE, BUT THEN A COLD FRONT MOVING IN FRIDAY WILL BRING CLOUDS AND
PRECIPITATION TO HELP LOWER MAX T`S INTO THE MIDDLE TO UPPER 80S
SATURDAY. MAX TEMPS WILL BASICALLY STAY IN THE 80S SUNDAY AS WELL,
THEN BEGIN REBOUNDING UPWARD MONDAY AND TUESDAY INTO THE LOWER 90S.
WINDS DO NOT LOOK TO BE TOO STRONG THROUGH THE WED NT THROUGH TUE
PERIOD, BUT WILL MAINTAIN A SOUTHERLY FLOW SUNDAY INTO TUESDAY.
MINIMUM TEMPERATURES IN THE LOWER TO MIDDLE 60S THURSDAY WILL RISE
TO THE MIDDLE 60S NORTHWEST TO LOWER TO MID 70S SOUTHEAST FRIDAY,
SATURDAY, SUNDAY, MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE AUG 21 2012
VFR CIGS EXPECTED THROUGH ENTIRE TAF PERIOD. SOUTHERLY WINDS WILL CONTINUE
AROUND 10 KT THROUGH TODAY AND INTO THE EVENING. WINDS WILL INCREASE
12 TO 20 KT TOMORROW IN ASSOCIATION WITH AN INTENSIFYING LEE SURFACE
TROUGH. CONVECTION IS POSSIBLE TOMORROW NIGHT BUT THIS IS OUTSIDE THE
TAF PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 89 65 91 / 10 10 30 30
GCK 61 91 64 92 / 10 10 30 30
EHA 61 89 63 91 / 10 10 20 30
LBL 60 90 64 91 / 10 10 30 30
HYS 60 91 65 92 / 10 10 30 30
P28 61 91 66 90 / 10 10 30 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...BURKE
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
100 PM CDT TUE AUG 21 2012
...UPDATE TO SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 900 AM CDT TUE AUG 21 2012
THE 21.12Z 250 HPA RAOB MAP NETWORK SHOWED TWO JETS ACROSS NORTH AMERICA.
ONE AROUND 100 KT WAS LOCATED ACROSS THE PACIFIC NORTHWEST. ANOTHER
ONE THAT WAS FAIRLY STRONG FOR THIS TIME OF YEAR /145 KT/ WAS LOCATED
ACROSS NEW ENGLAND. AT 500 HPA, A SHORTWAVE TROF WAS JUST WEST OF OREGON
AND WASHINGTON. A 590 DM ANTICYCLONE WAS LOCATED OVER THE DESERT SOUTHWEST.
FINALLY, AN ELONGATED TROF EXTENDED FROM CENTRAL QUEBEC TO THE NORTHERN
GULF OF MEXICO. AT 700 HPA, TEMPS WERE IN THE 6 TO 7 DEG C RANGE ACROSS
KANSAS...BASICALLY NOT MUCH CHANGE FROM 24 HOURS AGO. THE IMPRESSIVE
COLD POOL FOR AUGUST WITH VALUES IN THE 0 TO -3 DEG C RANGE WERE LOCATED
ACROSS THE OHIO RIVER VALLEY AND NORTHEAST. AT 850 HPA, LOW DEWPOINT
DEPRESSIONS ACROSS THE TEXAS PANHANDLE WERE ASSOCIATED WITH PRECIP AND
LOW CLOUDS. ACROSS SW KANSAS, THE THERMODYNAMICS WAS FAIRLY WARM AND
DRY. THE WARMEST PLUME WITH TEMPS IN THE LOWER 20S DEG C WAS OBSERVED
ACROSS THE NORTHERN HIGH PLAINS. AT THE SFC, HIGH PRESSURE EXTENDED
ACROSS MUCH OF THE MIDWEST. WEAK RETURN FLOW WAS OBSERVED ACROSS THE
HIGH PLAINS. TROPICAL DEPRESSION NINE WAS LOCATED NEAR 15.2N 51.2W @ 21.09Z.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 100 PM CDT TUE AUG 21 2012
TONIGHT:
THE SHORT TERM METEOROLOGICAL CONCERN IS WHAT TO DO WITH POPS FOR THIS
EVENING. MESOSCALE (NAM, WRF) AND GLOBAL MODELS (GFS, ECMWF) PAINT DOUBT
ON CONVECTIVE PROSPECTS FOR THE EVENING. THIS IS A RESULT OF THE FACT
THAT THE UPPER LEVEL JET/WAVE IS EAST OF THE REGION AND CONVERGENCE
AT THE SURFACE IS FORECAST TO BE WEAK. 850 HPA THETA-E ADVECTION IS
FORECAST TO REMAIN WEAK AS WELL. RECENT HRRR RUNS HAS BEEN INDICATING
ISOLATED ACTIVITY ACROSS THE WESTERN ZONES THIS EVENING BUT THIS MODEL
HAS BEEN TRENDING DOWNWARD OVERALL IN THE LAST SEVERAL RUNS. AS A RESULT,
HAVE REMOVED WX FROM THE GRIDS AND GOING WITH A DRY FORECAST FOR THIS
EVENING. SOUTHERLY WINDS WILL CONTINUE THROUGH THE OVERNIGHT WITH MODERATE
DEWPOINTS AS WELL. LOOK FOR LOWS IN THE LOWER 60S DEG F.
TOMORROW:
THE LEE SURFACE TROUGH WILL STRENGTHEN TOMORROW AS MID TO UPPER LEVEL
FLOW BECOMES A BIT MORE PERPENDICULAR TO THE ROCKIES. I HAVE POPS INCREASING
UP TO THE SLIGHT CATEGORY TOWARDS 00Z TOMORROW EVENING AS WEAK 850 HPA
THETA-E ADVECTION STRENGTHENS AND SOME STORMS COULD FORM NEAR THE LEE
SURFACE TROUGH ACROSS THE W/NW ZONES. OTHERWISE, TOMORROW WILL BE MAINLY
DRY WITH HIGHS IN THE UPPER 80S TO AROUND 90 DEG F. THESE VALUES ARE
VERY CLOSE TO CLIMATOLOGY FOR THIS TIME OF YEAR. TOMORROW WILL BE A
BIT BREEZY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 358 AM CDT TUE AUG 21 2012
IT HAS BEEN QUITE A WHILE SINCE WE HAVE SEEN AN UPPER-LEVEL PATTERN
LIKE THE ONE EVOLVING THIS WEEK. IS IT POSSIBLE THAT RICH GULF
MOISTURE WILL ACTUALLY MAKE IT BACK INTO WESTERN KANSAS WITHOUT
MIXING OUT? AND IS IT POSSIBLE THAT AN UPPER-LEVEL TROUGH WILL
ACTUALLY APPROACH KANSAS FROM THE WEST, AND ACTUALLY TAP SOME OF
THIS MOISTURE TO PRODUCE A FEW ROUNDS OF SHOWERS AND
THUNDERSTORMS? IT CERTAINLY SEEMS THAT WAY IF THE 00Z GFS AND
ECMWF COME ANYWHERE CLOSE TO VERIFYING. HOWEVER, BEFORE GETTING
TOO EXCITED ABOUT RAIN PROSPECTS, IT IS VERY UNCLEAR EXACTLY WHERE
IN THE PLAINS WILL HAVE THE BEST CHANCE FOR HEAVIER RAINFALL.
THE SYSTEM I AM REFERRING TO ABOVE WAS PART OF A LARGER UPPER-LEVEL
TROUGH THAT WAS SITUATED OFF OF THE WEST COAST AT 125W LONGITUDE
EARLY THIS MORNING. THIS SYSTEM IS PROGGED BY THE ECMWF AND GFS TO
SLOWLY PROGRESS INLAND INTO THE WESTERN UNITED STATES BY WEDNESDAY
AFTERNOON, NORTHERN ARIZONA BY THURSDAY NIGHT AND THEN INTO COLORADO
AND NEW MEXICO BY FRIDAY AFTERNOON. THE SPEED OF THIS SYSTEM
IS PROBLEMATIC GIVEN THE UNCERTAIN INTERACTION WITH A STRONGER JET
STREAM FURTHER NORTH. AHEAD OF THE UPPER-LEVEL LOW, A WEAK UPPER-LEVEL
SYSTEM THAT IS NOT DISCERNIBLE IN THE UPPER AIR DATA YET IS
ADVERTISED TO MOVE ACROSS THE CENTRAL PLAINS IN ZONAL FLOW FOR
WEDNESDAY AND THURSDAY. MEANWHILE, RICH LOW LEVEL MOISTURE THAT IS
CURRENTLY POSITIONED OVER THE SOUTHERN PLAINS IS ADVERTISED TO
MOVE NORTHWARD INTO KANSAS AS SOON AS WEDNESDAY EVENING. BY
WEDNESDAY EVENING, THIS WEAK SYSTEM IS PROGGED TO APPROACH THE
HIGH PLAINS. WITH DEWPOINTS CLIMBING INTO THE UPPER 50S ACROSS FAR
WESTERN KANSAS BY THIS TIME, ALONG WITH TEMPERATURES CLIMBING INTO
THE LOWER 90S, THERE MAY BE SUFFICIENT SURFACE BASED CAPE NEAR THE
LEE TROUGH IN EASTERN COLORADO FOR THUNDERSTORM INITIATION. ANY
STORMS THAT DO DEVELOP COULD GROW INTO A CLUSTER OF STORMS AND
PROGRESS ACROSS THE CENTRAL PLAINS WEDNESDAY NIGHT. BUT WHERE WILL
SUCH A CLUSTER BE LOCATED? IT IS SIMPLY TOO EARLY TO TELL. GIVEN
THE UNCERTAINTY, WE OPTED TO RETAIN THE 20-30% CHANCES FOR STORMS
DURING THIS PERIOD. THIS SYSTEM WILL STILL BE LOCATED OVER CENTRAL
KANSAS BY THURSDAY, SO IT IS POSSIBLE THAT THERE WILL BE LINGERING
AREAS OF SHOWERS AND THUNDERSTORMS SOMEWHERE ACROSS CENTRAL OR
EASTERN KANSAS ON THURSDAY. HENCE THE 20-30% CHANCES FOR
THUNDERSTORMS LOOK APPROPRIATE. TEMPERATURES FOR WEDNESDAY AND
THURSDAY WILL BE FAIRLY CLOSE TO CLIMATOLOGICAL AVERAGES, WITH
HIGHS IN THE UPPER 80S TO LOWER 90S AND LOWS MAINLY IN THE LOWER
TO MIDDLE 60S.
BY THURSDAY NIGHT AND FRIDAY, THE AFOREMENTIONED UPPER-LEVEL SYSTEM
OFF THE WEST COAST WILL BE GETTING CLOSER TO THE HIGH PLAINS REGION.
AND ALSO BY THIS TIME, THE MODELS, AND NOT JUST THE GFS, ARE SHOWING
EVEN HIGHER SURFACE DEWPOINTS WELL INTO THE 60S ACROSS SOUTHWEST AND
CENTRAL KANSAS. THIS SEEMS REASONABLE GIVEN THAT THE SOUTHERN EDGE
OF THE WESTERLIES WILL BE AS FAR SOUTH AS WE HAVE SEEN SINCE SPRING,
CAUSING A SOUTHWARD EXTENSION OF THE LEE TROUGH INTO SOUTHWEST
TEXAS AND NORTHERN MEXICO, AND A RESULTANT SURGE OF LOW LEVEL
MOISTURE FROM THE GULF OF MEXICO INTO KANSAS. IF THIS HAPPENS, THEN
SOME LOCATIONS ACROSS THE SOUTHERN OR CENTRAL PLAINS COULD EXPERIENCE
SOME MUCH NEEDED HEAVY RAINFALL. IT IS FAR TOO EARLY TO GET TOO
EXCITED ABOUT FURTHER DROUGHT RELIEF THIS FAR NORTHWEST IN THE
PLAINS, BUT THERE WILL BE CHANCES FOR THUNDERSTORMS EVERY DAY
THROUGH SATURDAY. HIGH TEMPERATURES DURING THIS PERIOD WILL DEPEND ON
HOW MUCH CLOUD COVER AND PRECIPITATION OCCUR. BUT IT DOESN`T LOOK
TOO HOT OR ALL THAT COOL EITHER, JUST BASICALLY WHAT ONE WOULD
EXPECT FOR THIS TIME OF YEAR, WITH HIGHS MAINLY IN THE 80S TO
PERHAPS AS HIGH AS 90. LOWS WILL BE HELD UP BY THE HIGHER DEWPOINTS
AND SHOULD BE MAINLY IN THE 60S.
A CLEARING TREND SHOULD COMMENCE BY SUNDAY PROVIDED THAT THE UPPER
LEVEL SYSTEM IS EAST OF OUR AREA BY THIS TIME AS ADVERTISED BY ALL
OF THE MODELS. HOWEVER, NEAR SEASONABLE TEMPERATURES CAN BE
EXPECTED TO PERSIST GIVEN THAT UPPER-LEVEL TROUGHING MAY STILL BE
NOT TOO FAR TO OUR EAST BY THIS TIME, WITH AN ABSENCE OF STRONG
LOW-LEVEL WARM ADVECTION. HOWEVER, BY EARLY TO MID NEXT WEEK, WARMER
TEMPERATURES WILL BE RETURNING TO THE PLAINS AS UPPER-LEVEL TROUGHING
DEVELOPS ACROSS THE NORTHWESTERN UNITED STATES. HIGH TEMPERATURES SHOULD
REBOUND INTO THE LOWER TO MIDDLE 90S BY TUESDAY AND POSSIBLY EVEN THE
UPPER 90S BY WEDNESDAY.
AFTER WEDNESDAY, LARGE DIFFERENCES START TO APPEAR IN THE MODELS,
ESPECIALLY IN REGARDS TO THE STRENGTH OF UPPER-LEVEL RIDGING ACROSS
THE PLAINS. THE 00Z GFS LOOKS SIMILAR TO THE 12Z ECMWF, WITH STRONGER
RIDGING OVER THE SOUTHERN AND EVEN CENTRAL PLAINS. THE 00Z ECMWF ADVERTISES
A WEAKER RIDGE BUT THIS MAY BE AN ABERRANT MODEL RUN SINCE THE GEM
SHOWS MORE RIDGING LIKE THE GFS. SO FAIRLY HOT WEATHER MAY PERSIST WITH
HIGHS IN THE 90S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE AUG 21 2012
VFR CIGS EXPECTED THROUGH ENTIRE TAF PERIOD. SOUTHERLY WINDS WILL CONTINUE
AROUND 10 KT THROUGH TODAY AND INTO THE EVENING. WINDS WILL INCREASE
12 TO 20 KT TOMORROW IN ASSOCIATION WITH AN INTENSIFYING LEE SURFACE
TROUGH. CONVECTION IS POSSIBLE TOMORROW NIGHT BUT THIS IS OUTSIDE THE
TAF PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 61 89 65 / 10 10 10 30
GCK 86 61 91 64 / 10 10 10 30
EHA 82 61 89 63 / 10 10 10 20
LBL 85 60 90 64 / 10 10 10 30
HYS 90 60 91 65 / 10 10 10 30
P28 87 61 91 66 / 10 10 10 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
417 PM EDT TUE AUG 21 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR TROF OVER ERN CAN/NE CONUS THAT IS SLOWLY
LIFTING OUT AND AN UPR RDG IN THE ROCKIES/PLAINS. SFC HI PRES
CENTERED OVER SW WI/LGT WLY FLOW ON ITS NRN FLANK AS WELL AS VERY
DRY AIR SHOWN ON THE 12Z INL/MPX RAOBS ARE BRINGING A TRANQUIL DRY
DAY TO UPR MI. THE ONLY FLY IN THE OINTMENT IS SOME MAINLY HI CLDS
DRIFTING SEWD INTO MAINLY THE E HALF OF THE CWA. THESE CLDS ARE ON
THE SRN FLANK OF AREA OF THICKER CLDS/A FEW -SHRA OVER ONTARIO
ASSOCIATED WITH DEEPER MSTR DEPICTED ON THE 12Z YPL RAOB AND WAD IN
ADVANCE OF SHRTWV EMBEDDED IN NW FLOW ALF AND NOW MOVING INTO FAR NW
ONTARIO.
MAIN FCST CONCERNS THRU WED WL BE PCPN CHCS ASSOCIATED WITH SHRTWV
FCST TO DROP SEWD THRU ONTARIO.
TNGT...SHRTWV NOW MOVING INTO FAR NW ONTARIO AND ASSOCIATED SFC LO
IS PROGGED TO DRIFT SEWD TO JUST W OF JAMES BAY BY 12Z WED.
ATTENDANT SFC TROF IS FCST TO STRETCH FM SFC LO WSWD THRU NRN LK SUP
TO NEAR ISLE ROYALE. THE EXPECTED MOTION OF THE SHRTWV INDICATES
BEST DPVA/DEEPER DEEP LYR QVECTOR CNVGC WL REMAIN FOCUSED IN ONTARIO.
ANOTHER SIGNIFICANT DETRIMENT TO PCPN CHCS WL BE VERY DRY LLVL AIR
SHOWN ON THE 12Z MPX/INL RAOBS AS INCRSG LLVL WSW FLOW TO THE S OF
SFC-H85 TROF WL BE DRAWING THIS AIR TOWARD UPR MI. SO ALTHOUGH
MODELS SHOW AN EXPANDING AREA OF H7 MSTR RELATED TO ISENTROPIC
ASCENT ON THE 305K SFC...NAM FCST SDNGS INDICATE THIS MOISTER LYR WL
BE RATHER THIN AND CAP MUCH DRIER LLVLS. THE GFS SHOWS MORE LLVL
MSTR...BUT WL TEND TO FOLLOW THE NAM GUIDANCE CONSIDERING THE
DRYNESS OF THE LLVLS OBSVD UPSTREAM. FOR THESE REASONS...OPTED TO GO
DRY TNGT AND LIMIT SCHC POPS ONLY TO THE FAR NRN CWA NEAR INCOMING
SFC TROF. OTRW...INCRSG WSW FLOW WL TEND TO LIMIT THE DIURNAL TEMP
FALL...ESPECIALLY IN DOWNSLOPE AREAS NEAR LK SUP THAT WL ALSO SEE
MORE AC RELATED TO H7 MOISTENING OVERNGT.
WED...SHRTWV TO THE NE IS PROGGED TO SLIDE TO THE E...TAKING DEEP
LYR QVECTOR CNVGC/H7 MSTR WITH IT. IN THE ABSENCE OF SGNFT MID LVL
FORCING AND WITH LLVL DRY AIR LINGERING TO THE S OF SFC LO PRES
TROF...THINK PCPN CHCS ARE MINIMAL. ALTHOUGH THE 12Z GFS GENERATES
SOME SPOTTY LGT QPF OVER PORTIONS OF MAINLY THE NCNTRL AND E...
OPTED TO FOLLOW THE BULK OF OTHER GUIDANCE AND KEEP THE LAND CWA
DRY...WITH SCHC POPS RESTRICTED TO NE LK SUP...CLOSER TO MID LVL
FORCING/MSTR. WITH H85 TEMPS PROGGED TO PEAK FM ARND 15C OVER THE E
TO 17C OVER THE W...EXPECT A WARMER DAY. DEEP MIXING ON NAM FCST
SDNGS SUG HI TEMPS WL REACH THE MID 80S OVER THE INTERIOR. A
WEAKENING PRES GRADIENT IN THE AFTN WL ALLOW FOR LK BREEZES TO FORM
AND MODERATE TEMPS NEAR THE LKSHORES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 412 PM EDT TUE AUG 21 2012
WEDNESDAY NIGHT...
WILL BEGIN WITH NW FLOW ALOFT AT 00Z THURSDAY /AND A WEAK SFC FRONT
NEARLY STATIONARY W TO E OVER THE CWA/...WITH A WEAK 500MB RIDGE SET
UP ALONG THE RED RIVER VALLEY OF THE N. EXPECT THIS RIDGE TO PUSH
ACROSS THE UPPER GREAT LAKES THURSDAY MORNING INTO THE EARLY
AFTERNOON HOURS...BEFORE GETTING PUSHED E /THANKS THE TO THE E
MOTION OF THE CURRENT TROUGH SET UP LONG THE PACIFIC COAST/. WEAK S
FLOW SHOULD HELP KEEP TEMPS ROUGHLY 5F WARMER THAN TONIGHT.
THURSDAY AFTERNOON THROUGH FRIDAY NIGHT...
LOOK FOR THE N EXTENT OF THE PACIFIC TROUGH TO PUSH ACROSS THE
DAKOTAS THURSDAY MORNING...AND ACROSS THE UPPER GREAT LAKES THURSDAY
AFTERNOON INTO THURSDAY NIGHT. FCST MODELS ARE PRETTY CONSISTENT IN
HAVING THE TROUGH DIRECTLY OVERHEAD AT 18Z FRIDAY...BEFORE SHIFTING
NE TO ONTARIO AND W QUEBEC. THE MAIN CONCERN WOULD STILL BE SLIGHTLY
STRONGER S WINDS FRIDAY MORNING W INTO THE AFTERNOON HOURS E.
SATURDAY THROUGH SUNDAY...
A STRONGER 500MB LOW WILL POSITION ITSELF OVER S SASKATCHEWAN
SATURDAY MORNING...AND CENTRAL MANITOBA BY 06Z SUNDAY. THE NEARLY
STACKED SYSTEM SHOULD RESULT THE FRONTAL BOUNDARY OVER THE CWA
LIFTING N AS A WARM FRONT...AND WARMER AIR SURGING N FOR
SATURDAY...WITH WIDESPREAD 80 DEGREE TEMPS AS 850MB TEMPS PUSH INTO
THE 16-18C RANGE. MUCH OF THE CLOUD COVER AND PRECIP SHOULD SHOULD
REMAIN W...CLOSER TO THE NEARING COLD FRONT ACROSS E ND AND W MN.
THE 21/00Z CANADIAN MODEL...WHILE HAVING A SIMILAR IDEA...IS ON THE
NORTHERN FRINGE OF SOLUTIONS. ON THE OTHER HAND...THE 21/06Z GFS IS
A BIT FARTHER SOUTH. THE DIFFERENCE FROM THE 2 IS ROUGHLY
200MI...WHICH IS NOT TOO BAD FOR A 120HR OR MORE FCST. THESE
DIFFERENCES BECOME A BIT MORE PRONOUNCED ACROSS S HUDSON BAY/N
ONTARIO SUNDAY NIGHT...BUT SHOULD NOT IMPACT OUR FCST TOO
GREATLY...AS A TROUGH WILL CONTINUE TO DOMINATE THE UPPER GREAT
LAKES REGION /SATURDAY NIGHT THROUGH AT LEAST SUNDAY NIGHT/.
MONDAY AND TUESDAY...
WRAP AROUND MOISTURE WILL BE POSSIBLE WITH COOLER AIR SLIDING IN ON
NW WINDS OFF THE GFS. HOWEVER...THIS IS HIGHLY DEPENDENT ON WHERE
THE STILL RELATIVELY STACKED LOW DECIDES TO GO. THE MORE PROGRESSIVE
N LOW OFF THE ECMWF STILL TRIES TO AMPLIFY THE SYSTEM TO OUR S
/ACROSS MO/IA/IL/WI/...WITH ANOTHER ROUND OF SHOWERS AND POSSIBLY TS
MONDAY MORNING AND AFTERNOON MAINLY CENTRAL AND E.
THE 21/00Z ECMWF AND 06Z GFS BECOME COMPLETELY OUT OF PHASE OVER THE
PACIFIC NW BY 00Z SUNDAY WRT THE 500MB PATTERN. LUCKILY THIS DOES
NOT SEEM TO NEGATIVELY IMPACT THE UPPER GREAT LAKES REGION UNTIL
MONDAY AFTERNOON/EVENING. AS A RESULT OF AN EXTREMELY LOW CONFIDENCE
FORECAST BEYOND MONDAY...WILL NOT TRY TO DO TOO MUCH OVER CLIMO. BY
DAYBREAK TUESDAY THE GFS HAS A SIZABLE TROUGH ACROSS THE GREAT
LAKES...WHILE THE ECMWF SHIFTS A HIGH AMPLITUDE RIDGE OVERHEAD. THE
MAIN CONCERN WITH A SOLID MODEL BLEND WOULD BE THE ISSUES PRODUCED
BY THE GFS AND CONVECTIVE FEEDBACK. ON A POSITIVE NOTE...THE 12Z
GFS/ECMWF DO LOOK A LITTLE MORE IN AGREEMENT FOR MONDAY AND
TUESDAY...WITH A RIDGE BUILDING IN MONDAY NIGHT INTO TUESDAY. WILL
SEE IF THIS TREND HOLDS UP WITH THE 18Z GFS AND 00Z RUNS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 131 PM EDT TUE AUG 21 2012
WITH RELATIVELY DRY LOW-LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THIS FCST PERIOD AT KIWD/KCMX/KSAW. MODEST LOW-LEVEL JET ARRIVING
OVERNIGHT TONIGHT WILL LEAD TO POSSIBLE LLWS...MAINLY AT KCMX WHICH
WILL BE CLOSER TO AXIS OF SPEED MAX. WITH DAYTIME HEATING ON WED...
THESE STRONGER WINDS WILL MIX OUT AND RESULT IN A GUSTY WSW WIND.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT TUE AUG 21 2012
EXPECT SW WINDS VEERING W TO INCREASE UP TO 25 KTS LATER TONIGHT/
EARLY WED...STRONGEST IN THE AREA BETWEEN THE KEWEENAW AND ISLE
ROYALE WHERE TERRAIN ACCENTUATES THIS FLOW...AS A LO PRES TROF
PRESSES INTO LAKE SUPERIOR FROM ONTARIO. LIGHT WINDS WILL THEN
PREVAIL FROM WED AFTERNOON INTO THE WEEKEND BEFORE THE APPROACH OF A
STRONGER DISTURBANCE/COLD FRONT MIGHT CAUSE S-SW WINDS TO INCREASE
UP TO 25 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
132 PM EDT TUE AUG 21 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EDT TUE AUG 21 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW THAT THE DEEP TROF THAT
HAS DOMINATED THE ERN CONUS FOR SEVERAL DAYS IS IN THE PROCESS OF
DEAMPLIFYING AND LIFTING OUT. SHORTWAVE THAT DROPPED THRU THE UPPER
LAKES YESTERDAY AND GENERATED SCT SHRA IS HEADING FOR THE UPPER OHIO
VALLEY. TO THE N...A SHORTWAVE IS MOVING SE THRU NRN MANITOBA TOWARD
NRN ONTARIO. IN RESPONSE...ZONE OF WAA IS SPREADING E ACROSS NRN
ONTARIO EARLY THIS MORNING. SOME CI IS PEELING S TOWARD THE UPPER
LAKES...BUT WAA MID CLOUDS AND ANY SHRA ARE STILL WELL N OF THE FCST
AREA. MAINLY CLEAR SKIES ACROSS THE FCST AREA AND LITTLE/NO WIND
COMBINED WITH THE MOISTURE FROM YESTERDAYS SHRA HAS LED TO RECENT
DEVELOPMENT OF SHALLOW PATCHY FOG AS A NUMBER OF OBS ARE SHOWING
WIDELY FLUCTUATING VIS.
MAIN FCST CONCERN IN THE SHORT TERM IS POTENTIAL OF CONVECTION
TONIGHT AS TRAILING SFC COLD FRONT FROM AFOREMENTIONED SHORTWAVE
SAGS S TOWARD THE UPPER LAKES. TODAY WILL BE A DRY DAY AS MAIN PUSH
OF WAA CONTINUES TO BE EASTWARD ACROSS NRN ONTARIO AHEAD OF
SHORTWAVE DROPPING SE INTO NRN ONTARIO. UNDER MOSTLY SUNNY
SKIES...MIXING UPWARDS OF 800MB OR SO ON FCST SOUNDINGS YIELDS MAX
TEMPS MAINLY IN THE MID/UPPER 70S. SOME LOCAL COOLING WILL OCCUR
NEAR THE GREAT LAKES.
TONIGHT...850MB THERMAL RIDGE AND MAIN ZONE OF WAA SINKS S INTO THE
UPPER LAKES. AXIS OF MODEST WRLY LOW-LEVEL JET OF 20-30KT REMAINS
MOSTLY JUST N OF UPPER MI...BUT PROXIMITY IS PROBABLY CLOSE ENOUGH
TO WARRANT A SLIGHT CHC OF SHRA/TSRA OVER THE KEWEENAW LATE TONIGHT.
CHC POPS WERE UTILIZED TO THE N ACROSS LAKE SUPERIOR. PER FCST
SOUNDINGS...LOW-LEVELS REMAIN DRY WITH MOISTURE CONFINED TO ROUGHLY
ABOVE 750MB. MIGHT BE ABLE TO GET 100-200J/KG OF CAPE FOR PARCELS
LIFTED FROM THE ELEVATED MOIST LAYER. GIVEN THE LACK OF
INSTABILITY...THE ELEVATED CONVECTION MAY HAVE TROUBLE PRODUCING
PCPN THAT WILL REACH THE GROUND. WITH S/SW WINDS STIRRING IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...TEMPS THERE MAY NOT FALL BLO
60F TONIGHT. EXPECT 50S ELSEWHERE. SHOULD BE ENOUGH DECOUPLING FOR
MINS DOWN TO AROUND 50F IN THE TRADITIONAL COLD SPOTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 450 AM EDT TUE AUG 21 2012
LARGE SCALE PATTERN FEATURES TROUGH OVER GREAT LAKES CONTINUING TO
BREAK DOWN INTO MORE ZONAL FLOW PATTERN BY LATE THIS WEEK. THIS
ALLOWS SHORTWAVE TROUGH EMERGING FROM TROUGH AXIS FROM GULF OF
ALASKA TO PACIFIC NORTHWEST TO PROPEL EAST INTO NORTHERN PLAINS
AND UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. AHEAD OF THE NORTHERN
PLAINS SHORTWAVE...SURFACE TROUGH OVER NORTHERN ONTARIO WILL DROP
INTO UPPER GREAT LAKES ON WEDNESDAY AND BECOME FAIRLY STATIONARY OVER
UPPER MICHIGAN THROUGH FRIDAY. COULD SEE AT LEAST A COUPLE INTERVALS
OF SHRA/TSRA THURSDAY INTO FRIDAY AS THE LARGER SCALE UPPER TROUGH
INTERACTS WITH THE SURFACE TROUGH.
MAJORITY OF MOISTURE ALONG AND AHEAD OF SURFACE TROUGH ON WEDNESDAY
IS H7-H5 WITH LIFT ACTING ON THIS LAYER OF MOISTURE. VERY LITTLE
MOISTURE IS PRESENT BLO H7...SO FOR WEDNESDAY HAVE KEPT POPS TIED
INTO THE AREA OF H7-H5 MOISTURE/UVM AND H7 MOISTURE ADVECTION.
STRONGEST PVA FM SHORTWAVE TRACKING ACROSS ONTARIO STAYS WELL TO THE
NORTH AND EAST OF UPR MICHIGAN...AS DOES DIVERGENCE ALOFT FM JET
STREAK PASSING JUST SOUTH OF JAMES BAY. OVERALL THERE IS NOT A LOT OF
FORCING TO JUSTIFY POPS OVER MOST OF CWA. KEPT SOME POPS IN THE EAST
CWA...BUT REMOVED POPS OVER THE CENTRAL CWA. GIVEN EXPECTED THINNING
MID CLOUDS BY AFTERNOON SHOULD SEE TEMPS WARM NICELY WITH STRONGER
1000-850MB SW WINDS PRESENT JUST AHEAD OF BOUNDARY DROPPING INTO
UPPER GREAT LAKES. NAM/GFS SOUNDINGS POINT TO MIXING UP TO 850-800MB.
MIXING TO H85 YIELDS RETURN TO THE 80S FOR MUCH OF THE AREA...BOOSTED
FURTHER BY MINIMAL LAKE BREEZES AS STRONGER 950-925MB SW WINDS HOLD
THROUGH THE AFTN. WITH ENOUGH SUNSHINE...IT IS LIKELY THAT SOME
AREAS OF CWA SEE TEMPS INTO THE MIDDLE 80S. MINIMUM IN PRECIP CHANCE
CONTINUES THROUGH MOST OF WEDNESDAY NIGHT AND MAYBE INTO THURSDAY
MORNING AS WELL AS MAIN FOCUS FOR SHRA/TSRA WILL BE TIED INTO LEAD
SHORTWAVE PUSHING INTO MINNESOTA BY 12Z THURSDAY OUT AHEAD OF H85-H5
TROUGH MOVING ACROSS THE NORTHERN PLAINS.
CHANCES FOR SHRA/TSRA INCREASE BY THURSDAY AFTERNOON AS THE LEAD
SHORTWAVE PRESSES INTO UPPER GREAT LAKES AND INTERACTS WITH
TEMPERATURE AND MOISTURE ADVECTION INTO SURFACE BOUNDARY PRESENT
OVER THE AREA. MAX H85 MOSITURE ADVECTION AND PVA FROM THE WAVE
COINCIDE OVER WEST HALF OF UPR MICHIGAN ON THURSDAY. INCREASED POPS
OVER THE WEST BUT ALSO WENT WITH SLIGHT CHANCE FOR ALL AREAS DUE TO
THE LOW-LEVEL TROUGH IN THE VICINITY. SHOWED WARMEST TEMPS ON
THURSDAY OVER THE EAST AS THERE IS HIGHER PROBABILITY IT REMAINS
MOSTLY SUNNY THERE INTO THE EARLY-MID AFTERNOON. TEMPS WILL RANGE
FROM THE MID 70S AT THE COOLEST AND WITH ENOUGH SUNSHINE MAY BUMP
INTO THE MID 80S OVER THE EAST. SEEMS THAT BETTER CHANCES OF
SHRA/TSRA THURSDAY NIGHT SET UP MORE OVR LK SUPERIOR ON NOSE OF H85
JET AND CLOSER TO TRACK OF LEAD SHORTWAVE LIFTING INTO ONTARIO.
CANNOT RULE OUT CHANCES ANYWHERE THOUGH AS AGAIN...THE SURFACE FRONT
IS STILL FORECAST CLOSE TO UPR MICHIGAN. INTO FRIDAY...BEFORE IT
LOOKED LIKE THIS WOULD BE THE DAY OF GREATEST RAIN CHANCES. NOT SO
CLEAR CUT NOW THOUGH...AND UNFORTUNATELY THIS FORECAST UNCERTAINTY
PERSISTS RIGHT THROUGH THE UPCOMING WEEKEND AS WELL. STILL PREFER TO
HOLD ONTO THE IDEA FM THE ECMWF AND GEM-NHEM WITH ANOTHER BOUT OF
H85 MOISTURE ADVECTION KICKING OFF SHRA/TSRA ALONG H5 TROUGH AXIS
OVR UPR MICHIGAN DURING PEAK HEATING. STRONGEST HEIGHT FALLS THEN
SHIFT TO THE NORTH AND EAST OF CWA FRIDAY NIGHT SO EXPECT GREATEST
RAIN CHANCES TO PROBABLY DO SO AS WELL.
CURRENT FORECAST FOR SATURDAY AND SUNDAY FEATURES CHANCES FOR
SHRA/TSRA BUT MODEL TRENDS NOW SUGGEST IT MAY END UP BEING MOSTLY
FREE OF RAIN...AT LEAST SATURDAY AND SATURDAY NIGHT. ONLY MODEL THAT
HITS POPS UP THIS WEEKEND IS THE GFS...BUT SINCE GFS SOLUTION
CONTINUES TO BE INFLUENCED BY CONVECTIVE FEEDBACK...HPC HAS TOSSED
IT OUT FOR THIS FORECAST CYCLE. BASED ON POSITION OF INCOMING UPPER
TROUGH OVR SCNTRL CANADA...UPPER JET...SFC FRONT AND H85-H7 MOISTURE
ADVECTION...BETTER SHRA/TSRA CHANCES WOULD SEEM TO SPLIT MORE AROUND
UPR MICHIGAN THROUGH THE WEEKEND. LATER FORECASTS MAY NEED TO TREND
DRIER. LACK OF CLOUDS/SHRA/TSRA WOULD LEAD TO WARMER TEMPS AS WELL
SINCE H85 TEMPS ARE A WARM 15-18C AND LOW-LEVEL WINDS ARE SOUTHWEST
AHEAD OF LARGER SCALE TROUGH. CURRENT FORECAST POINTS TO UPPER
70S-LOWER 80S WITH MOSTLY CLOUDY SKIES AND A CHANCE FOR RAIN. WHEN
IN REALITY IT VERY WELL COULD END UP MOSTLY SUNNY WITH HIGHS IN THE
MID-UPPER 80S. BY LATE SUNDAY...BETTER CHANCES OF SHRA/TSRA PRESS
ACROSS CWA WITH COLD FRONT TIED TO UPPER TROUGH MOVING FM MANITOBA
INTO ONTARIO. EXACT TIMING WITH THIS FRONT WILL REMAIN A QUESTION
UNTIL WE GET CLOSER TO THE WEEKEND THOUGH...SO KEPT WITH CONSENSUS
APPROACH FOR POPS AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 131 PM EDT TUE AUG 21 2012
WITH RELATIVELY DRY LOW-LEVELS...VFR CONDITIONS WILL PREVAIL THRU
THIS FCST PERIOD AT KIWD/KCMX/KSAW. MODEST LOW-LEVEL JET ARRIVING
OVERNIGHT TONIGHT WILL LEAD TO POSSIBLE LLWS...MAINLY AT KCMX WHICH
WILL BE CLOSER TO AXIS OF SPEED MAX. WITH DAYTIME HEATING ON WED...
THESE STRONGER WINDS WILL MIX OUT AND RESULT IN A GUSTY WSW WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EDT TUE AUG 21 2012
LIGHTER WINDS BECOMING WEST SOUTHWEST AND INCREASE TO 15-25 KTS
LATER TODAY INTO TONIGHT AS FRONT DROPPING IN FROM ONTARIO TIGHTENS
PRESSURE GRADIENT. STRONGEST WINDS WILL OCCUR OVER WEST AND NORTH
CENTRAL LK SUPERIOR BETWEEN ISLE ROYALE AND TIP OF KEWEENAW. WINDS
RELAX ON WEDNESDAY AS PRESSURE GRADIENT SLACKENS. EXPECT WINDS TO
INCREASE AGAIN FOR THE UPCOMING WEEKEND AS STRONGER LOW PRESSURE
SYSTEM AND FRONT APPROACH FROM THE PLAINS. COULD SEE SOUTHERLY
GUSTS TO 25 KTS OVER EASTERN SECTIONS SATURDAY NIGHT INTO SUNDAY
JUST AHEAD OF THE FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
412 PM CDT TUE AUG 21 2012
.UPDATE...
.DISCUSSION...
RADAR INDICATES ISOLATED THUNDERSTORMS MAY BE DEVELOPING A BIT
FARTHER NORTH THAN FCST BY THE HRRR. SO A MINOR ADJUSTMENT FOR
ISOLATED EVENING TSTMS HAS BEEN MADE ACROSS FAR SOUTHERN
NEBRASKA.
&&
.PREV DISCUSSION... /ISSUED 332 PM CDT TUE AUG 21 2012/
DISCUSSION...
AN AREA OF WEAK CU IS FORMING ACROSS FAR SW NEB THIS AFTERNOON.
THE HRRR SUGGEST ISOLATED STORM DEVELOPMENT WITH STORM MOTION
SOUTHEAST AND AWAY FROM THE FCST AREA. OTHERWISE NO SIGNIFICANT
WEATHER IS EXPECTED OVERNIGHT. LOW PRESSURE ACROSS THE NRN HIGH
PLAINS AND A WARM FRONT STRETCHING ACROSS NRN NEB SHOULD KEEP MIN
TEMPS WARMER TONIGHT. THE SFC LOW IS EXPECTED TO BEGIN MOVING
SLOWLY SOUTH OVERNIGHT.
ON WEDNESDAY...THE LOW DROPS SOUTH TOWARD SWRN SD AND NW NEB BY
LATE AFTERNOON. MOISTURE ALOFT WILL INCREASE AHEAD OF A WEAK NRN
STREAM DISTURBANCE. THE COMBINATION OF THE DISTURBANCE ACROSS THE
NRN PLAINS...INCREASING MOISTURE ALOFT AND STRONG SFC HEATING
SHOULD PRODUCE ISOLATED LATE AFTERNOON TSTMS. MODEL QPF IS
IGNORING THE VERY DRY AIR BELOW 700 MB AND PRODUCING QPF AS HIGH
AS .66 INCHES. THE NAM INDICATED DELTA T-TD HIGHER THAN 40 DEGREES
YET STILL PRODUCED 2/3 OF AN INCH OF QPF. SO POPS ARE LIMITED TO
THE ISOLATED CATEGORY. K INDICES IN THE MODEL ARE BELOW 40C WHICH
IS GENERALLY THE LIMIT FOR SCATTERED STORM COVERAGE. WE WILL SEE
IF THE MODELS CAN SHOW DEEPER MOISTURE BEFORE RAISING FCST POPS.
IN THE WAKE OF THE DISTURBANCE WEDNESDAY NIGHT...A WEAK COLD FRONT
WILL DROP THROUGH WRN NEB IN THE MORNING ANGLED SW THROUGH KIML AND INTO
A SFC HEAT LOW ACROSS ERN COLO. THE FRONT WILL DRIFT SOUTH AND
EAST THROUGHOUT THE AFTERNOON. SOUTHWEST WINDS BELOW 700 MB WILL HAVE
EVACUATED WHATEVER MOISTURE WAS THERE AND THE DEPARTING UPPER
LEVEL DISTURBANCE WILL DRY OUT THE ATM ALOFT. THUS NO RAIN IS EXPECTED
THURSDAY EXCEPT PERHAPS ACROSS CNTL NEB DEPENDING ON THE LOCATION
OF THE FRONT.
A DEEP UPPER LEVEL DISTURBANCE WILL BE TRACKING THROUGH SRN
ALBERTA AND SRN SASKATCHEWAN FRIDAY. THIS SYSTEM SHOULD DRAW DEEPER
MOISTURE FROM TEXAS NORTH THROUGH WRN NEB DURING THE AFTERNOON AND
SUFFICIENT UPPER LEVEL FORCING SHOULD BE AVAILABLE FOR ISOLATED
STORM DEVELOPMENT FRIDAY AFTERNOON. A BROAD AREA OF STRATUS MAY DEVELOP
FRIDAY MORNING AS MOISTURE LIFTS NORTH. ALL SOLNS EXCEPT THE NAM12
SHOW THIS FORMING.
TEMPERATURES ARE EXPECTED TO RISE INTO THE 90S WEDNESDAY THROUGH
FRIDAY. VERTICAL MIXING PROFILES MAY BE LIMITED AS THE SFC LOW
WILL GENERALLY DROP DUE SOUTH THROUGH THE HIGH PLAINS VS TRACKING
EAST THROUGH SRN SD. SO MAX TEMPS FOLLOW A MIDDLE OF THE ROAD
APPROACH FOR A MIX OF HIGHS IN THE LOWER...MIDDLE AND A FEW UPPER 90S.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
DECENT LOW AND MID LEVEL MOISTURE WILL SPREAD NORTH INTO THE AREA
FROM THE SOUTH FRIDAY NIGHT AHEAD OF A DECENT MID LEVEL DISTURBANCE.
850 MB DEW PTS PER THE ECMWF ARE PROGGED TO RISE TO NEAR 16C.
CHANCES FOR RAIN ARE EXPECTED TO INCREASE SATURDAY AS THE
DISTURBANCE MOVES ACROSS THE AREA...BUT RIGHT NOW MODELS INDICATING
THE BEST FOCUS FOR RAINFALL/CONVECTION MAY STAY SOUTH AND EAST OF
THE AREA. SO WON/T GET CARRIED AWAY WITH POPS...AND JUST CONTINUE
THE INHERITED 40 PERCENT CHANCES. SYSTEM MOVES EAST OF THE AREA
SUNDAY...WITH DRY WEATHER EXPECTED THE FIRST OF NEXT WEEK.
TEMPERATURE WISE...NEAR SEASONAL HIGHS IN THE 80S ARTE EXPECTED FOR
THE WEEKEND. BY EARLY NEXT WEEK HIGHS COULD REACH BACK INTO THE
LOWER 90S. LOWS WILL BE QUITE MILD WITH THE INCREASED
MOISTURE...WITH MOST AREAS STAYING IN THE 60S AT NIGHT.
AVIATION...
MOSTLY CLEAR SKIES AND VFR CONDITIONS WILL PREVAIL THE
NEXT 24 HRS ACROSS WESTERN AND NORTH CENTRAL NEB. SFC WINDS WILL BE
SOUTH TO SOUTHEAST AT 5 TO 15 KTS.
FIRE WEATHER...
BREEZY SOUTHERLY WINDS WILL INCREASE WEDNESDAY IN
RESPONSE TO A TIGHTENING PRESSURE GRADIENT ACROSS THE AREA. SOME
INCREASE IN LOW LEVEL MOISTURE IS EXPECTED...AND MINIMUM RELATIVE
HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 20 PERCENT. THE NAM
MODEL MAY BE DRYING OUT THE LOW LEVELS A LITTLE TOO MUCH ACROSS
CENTRAL NEBRASKA BASED ON WHAT IS OCCURRING TODAY...AND WILL FORGO A
FIRE WEATHER WATCH FOR THE THAT AREA AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
332 PM CDT TUE AUG 21 2012
.DISCUSSION...
AN AREA OF WEAK CU IS FORMING ACROSS FAR SW NEB THIS AFTERNOON.
THE HRRR SUGGEST ISOLATED STORM DEVELOPMENT WITH STORM MOTION
SOUTHEAST AND AWAY FROM THE FCST AREA. OTHERWISE NO SIGNIFICANT
WEATHER IS EXPECTED OVERNIGHT. LOW PRESSURE ACROSS THE NRN HIGH
PLAINS AND A WARM FRONT STRETCHING ACROSS NRN NEB SHOULD KEEP MIN
TEMPS WARMER TONIGHT. THE SFC LOW IS EXPECTED TO BEGIN MOVING
SLOWLY SOUTH OVERNIGHT.
ON WEDNESDAY...THE LOW DROP SOUTH ACROSS SWRN SD AND NW NEB BY
LATE AFTERNOON. MOISTURE ALOFT WILL INCREASE AHEAD OF A WEAK NRN
STREAM DISTURBANCE. THE COMBINATION OF THE DISTURBANCE ACROSS THE
NRN PLAINS...INCREASING MOISTURE ALOFT AND STRONG SFC HEATING
SHOULD PRODUCE ISOLATED LATE AFTERNOON TSTMS. MODEL QPF IS
IGNORING THE VERY DRY AIR BELOW 700 MB AND PRODUCING QPF AS HIGH
AS .66 INCHES. THE NAM INDICATED DELTA T-TD HIGHER THAN 40 DEGREES
YET STILL PRODUCED 2/3 OF AN INCH OF QPF. SO POPS ARE LIMITED TO
THE ISOLATED CATEGORY. K INDICES IN THE MODEL ARE BELOW 40C WHICH
IS GENERALLY THE LIMIT FOR SCATTERED STORM COVERAGE. WE WILL SEE
IF THE MODELS CAN SHOW DEEPER MOISTURE BEFORE RAISING FCST POPS.
IN THE WAKE OF THE DISTURBANCE WEDNESDAY NIGHT...A WEAK COLD FRONT
WILL DROP THROUGH WRN NEB IN THE MORNING ANGLED SW THROUGH KIML AND INTO
A SFC HEAT LOW ACROSS ERN COLO. THE FRONT WILL DRIFT SOUTH AND
EAST THROUGHOUT THE AFTERNOON. SOUTHWEST WINDS BELOW 700 MB WILL HAVE
EVACUATED WHATEVER MOISTURE WAS THERE AND THE DEPARTING UPPER
LEVEL DISTURBANCES DRY OUT THE ATM ALOFT. THUS NO RAIN IS EXPECTED
THURSDAY EXCEPT PERHAPS ACROSS CNTL NEB DEPENDING ON THE LOCATION
OF THE FRONT.
A DEEP UPPER LEVEL DISTURBANCE WILL BE TRACKING THROUGH SRN
ALBERTA AND SRN SASKATCHEWAN FRIDAY. THIS SYSTEM SHOULD DRAW DEEPER
MOISTURE FROM TEXAS NORTH THROUGH WRN NEB DURING THE AFTERNOON AND
SUFFICIENT UPPER LEVEL FORCING SHOULD BE AVAILABLE FOR ISOLATED
STORM DEVELOPMENT FRIDAY AFTERNOON. A BROAD AREA OF STRATUS MAY DEVELOP
FRIDAY MORNING AS MOISTURE LIFTS NORTH. ALL SOLNS EXCEPT THE NAM12
SHOW THIS FORMING.
TEMPERATURES ARE EXPECTED TO RISE INTO THE 90S WEDNESDAY THROUGH
FRIDAY. VERTICAL MIXING PROFILES MAY BE LIMITED AS THE SFC LOW
WILL GENERALLY DROP DUE SOUTH THROUGH THE HIGH PLAINS VS TRACKING
EAST THROUGH SRN SD. SO MAX TEMPS FOLLOW A MIDDLE OF THE ROAD
APPROACH FOR A MIX OF HIGHS IN THE LOWER...MIDDLE AND A FEW UPPER 90S.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
DECENT LOW AND MID LEVEL MOISTURE WILL SPREAD NORTH INTO THE AREA
FROM THE SOUTH FRIDAY NIGHT AHEAD OF A DECENT MID LEVEL DISTURBANCE.
850 MB DEW PTS PER THE ECMWF ARE PROGGED TO RISE TO NEAR 16C.
CHANCES FOR RAIN ARE EXPECTED TO INCREASE SATURDAY AS THE
DISTURBANCE MOVES ACROSS THE AREA...BUT RIGHT NOW MODELS INDICATING
THE BEST FOCUS FOR RAINFALL/CONVECTION MAY STAY SOUTH AND EAST OF
THE AREA. SO WON/T GET CARRIED AWAY WITH POPS...AND JUST CONTINUE
THE INHERITED 40 PERCENT CHANCES. SYSTEM MOVES EAST OF THE AREA
SUNDAY...WITH DRY WEATHER EXPECTED THE FIRST OF NEXT WEEK.
TEMPERATURE WISE...NEAR SEASONAL HIGHS IN THE 80S ARTE EXPECTED FOR
THE WEEKEND. BY EARLY NEXT WEEK HIGHS COULD REACH BACK INTO THE
LOWER 90S. LOWS WILL BE QUITE MILD WITH THE INCREASED
MOISTURE...WITH MOST AREAS STAYING IN THE 60S AT NIGHT.
&&
.AVIATION...
MOSTLY CLEAR SKIES AND VFR CONDITIONS WILL PREVAIL THE
NEXT 24 HRS ACROSS WESTERN AND NORTH CENTRAL NEB. SFC WINDS WILL BE
SOUTH TO SOUTHEAST AT 5 TO 15 KTS.
&&
.FIRE WEATHER...
BREEZY SOUTHERLY WINDS WILL INCREASE WEDNESDAY IN
RESPONSE TO A TIGHTENING PRESSURE GRADIENT ACROSS THE AREA. SOME
INCREASE IN LOW LEVEL MOISTURE IS EXPECTED...AND MINIMUM RELATIVE
HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 20 PERCENT. THE NAM
MODEL MAY BE DRYING OUT THE LOW LEVELS A LITTLE TOO MUCH ACROSS
CENTRAL NEBRASKA BASED ON WHAT IS OCCURRING TODAY...AND WILL FORGO A
FIRE WEATHER WATCH FOR THE THAT AREA AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC/TALYOR
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
231 PM CDT TUE AUG 21 2012
.SHORT TERM...THROUGH THURSDAY NIGHT
230 PM CDT TUE AUG 21 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES WEDNESDAY THROUGH
THURSDAY NIGHT.
SURFACE ANALYSIS THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED OVER
EASTERN IOWA INTO CENTRAL WISCONSIN.
THE FIRST CONCERN IS WHETHER ANY VALLEY FOG WILL FORM AGAIN
TONIGHT. THE SURFACE HIGH WILL BE PULLING OFF TO THE SOUTHEAST AND
SHOULD BE CENTERED OVER INDIANA BY LATE TONIGHT. BOTH THE 21.12Z
NAM AND GFS SUGGEST A WARM FRONT WILL DEVELOP IN THE RETURN FLOW
FROM SOUTH DAKOTA INTO MISSOURI. AS THIS OCCURS...BOTH MODELS
ACTUALLY SHOW A LITTLE BIT OF RIDGING DEVELOPING NORTH OF THE
FRONT AND OVER THE AREA. THIS SHOULD ALLOW THE SURFACE WINDS TO
DECOUPLE ONCE AGAIN AND DEW POINTS SHOULD RECOVER INTO THE UPPER
40S. SKIES WILL BE CLEAR OVERNIGHT SO PLENTY OF POSITIVES FOR THE
FOG. BOTH THE NAM AND 21.17Z RAP BUFKIT SOUNDING FOR KLSE SHOW
SOUTHWEST WINDS AROUND 20 KNOTS JUST ABOVE THE SURFACE UP THROUGH
ABOUT 3 OR 4 THOUSAND FEET. THIS IS VERY SIMILAR TO A COUPLE OF
NIGHTS AGO EXPECT THE WINDS ARE ABOUT 180 DEGREES DIFFERENT IN
DIRECTION AND MAYBE A LITTLE STRONGER TONIGHT. SOME FOG DID FORM
IN THESE SIMILAR CONDITIONS SATURDAY MORNING SO PLAN TO INCLUDE A
MENTION OF PATCHY FOG.
THE NEXT CONCERN IS WHETHER ANY RAIN WILL FORM WEDNESDAY AND
WEDNESDAY NIGHT IN THE RETURN FLOW. MODEL DIFFERENCES CONTINUE
WITH THE NAM AND GFS STILL SHOWING SOME RAIN DEVELOPING WHILE THE
21.00Z ECMWF REMAINS DRY. WHETHER THIS RAIN DEVELOPS OR NOT
DEPENDS ON HOW MUCH LOW LEVEL THERMODYNAMICS COME INTO PLAY. THE
NAM CONTINUES TO BE THE STRONGEST WITH THIS FORCING SHOWING WEAK
FRONTOGENESIS IN THE 1000-500 MB LAYER NORTH OF THE WARM FRONT.
THE ECMWF ALSO HAS A LITTLE BIT OF FRONTOGENESIS BUT ONLY UP
THROUGH 700 MB. THE BIG DIFFERENCE COMES IN THE ISENTROPIC
RESPONSE. THE NAM GENERATES UP TO 10 UBAR/S ON THE 310K SURFACE
WHILE THE GFS ONLY HAS ABOUT 3 UBAR/S AND THE ECMWF HAS BETWEEN 1
AND 2 UBAR/S. IF THIS RAIN DOES DEVELOP...THE NAM BUFKIT SOUNDINGS
SHOW CLOUD BASES WOULD BE ABOUT 10K FEET WITH LOTS OF DRY AIR
BELOW. WOULD NOT EXPECT MUCH MORE THAN SOME SPRINKLES OR A QUICK
SHOWER WITH A COUPLE HUNDREDTHS QPF.
THE MODEL DIFFERENCES CONTINUE INTO THURSDAY AND THURSDAY NIGHT AS
WELL. THE SHORT WAVE TROUGH COMING ONTO THE PACIFIC NORTHWEST
COAST TODAY WILL TOP THE ROCKIES AND START MOVING ACROSS THE UPPER
MIDWEST. THE ECMWF HAS BEEN VERY CONSISTENT SHOWING THE FILLING
UPPER LEVEL LOW WITH THIS SYSTEM TO BE MOVING NORTHEAST INTO
CENTRAL CANADA WHILE THE SHORT WAVE TROUGH COMES THROUGH WITH A
POSITIVE TILT. THE NAM AND GFS ARE SUGGESTING THAT A PIECE OF
ENERGY WILL BREAK OUT OF THE MEAN LONG WAVE TROUGH AXIS OR A NEW
SHORT WAVE TROUGH DEVELOPS IN THE LEE OF THE ROCKIES WEDNESDAY.
THESE MODELS THEN BRING THIS SHORT WAVE TROUGH ACROSS THE AREA
WITH A NEUTRAL TO NEGATIVE TILT AND QUICKER THAN THE POSITIVE
TILT OF THE ECMWF. AT THIS POINT...CONFIDENCE ON WHICH SOLUTION
WILL VERIFY IS NOT HIGH SO HAVE TRIED TO COMPROMISE BETWEEN THE
TWO WITH A SLIGHT NOD TOWARD THE ECMWF SOLUTION. WILL SHOW A SMALL
CHANCE OF RAIN ACROSS THE FAR NORTH THURSDAY MORNING AHEAD OF THE
ADVANCING WARM FRONT AND THEN 20 TO 30 PERCENT CHANCES DURING THE
AFTERNOON ACROSS THE WEST AND NORTH AS THE FORCING STARTS TO
INCREASE AHEAD OF THE APPROACHING SYSTEM. AS THE SHORT WAVE TROUGH
THEN COMES INTO LATER THURSDAY...IT SHOULD PRODUCE AROUND 4 PVU/S
OF VORTICITY ADVECTION IN THE 500-300 MB LAYER. NOT MUCH OF
SURFACE REFLECTION WITH THIS SYSTEM SO ONLY SOME WEAK
FRONTOGENESIS IN THE 1000-850 MB LAYER. SOME WEAK UP GLIDE OF 1-2
UBAR/S SHOULD CONTINUE ON THE 310K SURFACE ALONG WITH GETTING
INTO THE EASTERN AND CONVERGENT SIDE OF THE MOISTURE TRANSPORT
AXIS. ALL THIS FORCING LOOKS TO BE AT ITS STRONGEST THURSDAY NIGHT
ACROSS THE NORTH AND DID INCREASE THE RAIN CHANCE TO AROUND 60
THERE.
.LONG TERM...FRIDAY THROUGH TUESDAY
230 PM CDT TUE AUG 21 2012
THE RAIN THAT DEVELOPS THURSDAY/THURSDAY NIGHT SHOULD BE COMING TO
AN END FRIDAY INTO FRIDAY NIGHT AS THE SHORT WAVE TROUGH MOVES
PAST THE AREA. THE NEXT PIECE OF ENERGY WILL QUICKLY APPROACH FROM
THE WEST COAST WITH THE UPPER LEVEL LOW AGAIN MOVING ACROSS CANADA
ALLOWING A SOUTHWEST FLOW ALOFT TO DEVELOP ACROSS THE UPPER
MIDWEST. INITIALLY THE MODELS ARE IN GOOD AGREEMENT THAT A SHORT
WAVE TROUGH WILL BE IN THIS SOUTHWEST FLOW OVER THE MID PLAINS
STATES SATURDAY NIGHT BUT THEN DIVERGE AS THEY START TO LIFT THIS
WAVE NORTHEAST. THE GFS FLATTENS THIS WAVE OUT AND LIFTS IT
THROUGH QUICKER THAN EITHER THE 21.12Z GEM OR ECMWF. THE ECMWF IS
THE STRONGEST AND SLOWEST LIFTING THIS WAVE TO THE NORTHEAST. THE
DIFFERENCES COULD BE STEMMING FROM THE WIDE RANGE OF SOLUTIONS
THAT ARE SHOWING UP WITH A POTENTIAL TROPICAL SYSTEM APPROACHING
THE SOUTHEAST U.S. AND FOR NOW HAVE STAYED WITH THE MODEL
CONSENSUS GRIDS WITH 30 TO 50 PERCENT RAIN CHANCES SATURDAY NIGHT
THROUGH SUNDAY NIGHT WITH THE SYSTEM THEN MOVING PAST MONDAY.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1152 AM CDT TUE AUG 21 2012
MAIN CONCERN WILL BE RIVER VALLEY FOG/STRATUS POTENTIAL AGAIN
WEDNESDAY MORNING AT KLSE. HIGH PRESSURE WILL MAINTAIN CONTROL
ACROSS THE AREA FOR DRY/QUIET CONDITIONS. WITH RIDGE AXIS OVERHEAD
THROUGH THE NIGHTTIME HOURS...LOOK FOR CLEAR SKIES/LIGHT
WINDS AND A DRY AIRMASS. THIS WILL AGAIN SET UP RADIATIONAL FOG
CONDITIONS IN THE MISSISSIPPI RIVER CHANNEL WITH RELATIVELY WARMER WATER.
MODELS HOWEVER SHOWING FAIRLY BREEZY SOUTHWEST WINDS AT BLUFF-TOP
WHICH WILL LIKELY KEEP THE VISIBILITY UP AT KLSE AND PERHAPS
DEVELOP MORE OF A IFR/LIFR STRATUS CEILING INSTEAD. FAIRLY
CONFIDENT THIS WILL HAPPEN ALONG SOME OF THE MISSISSIPPI
CHANNEL/VALLEY...BUT NOT OVERLY CONFIDENT AT KLSE ITSELF. FOR
NOW...WILL INCLUDE VCFG MENTION IN THE 11-14Z TIME FRAME ALONG
WITH A SCT003 MENTION. DONT SEE ANY PROBLEMS AT KRST WITH VFR
CONDITION EXPECTED THROUGH 18Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CDT TUE AUG 21 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...DAS