Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/13/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
205 AM MST SUN AUG 11 2013
.SYNOPSIS...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS FROM TUCSON
EASTWARD AND SOUTHWARD THIS AFTERNOON AND THIS EVENING. DECREASING
CHANCES FOR THUNDERSTORMS WILL THEN OCCUR MONDAY THROUGH WEDNESDAY
AS DEEPER MOISTURE MOVES EAST OF THE AREA. SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS WILL THEN PREVAIL MAINLY EAST OF TUCSON DURING
THE LATTER PART OF THE WEEK.
&&
.DISCUSSION...PRONOUNCED MOISTURE GRADIENT ACROSS SE AZ EARLY THIS
MORNING...WITH DEWPOINTS VALID 09Z RANGING FROM THE MID 50S-MID 60S
ERN SECTIONS TO THE LOWER-MID 30S FROM TUCSON WWD. BLENDED TOTAL
PRECIP WATER IMAGERY ALSO DEPICTED THE DISTINCT MOISTURE GRADIENT
NICELY...WITH VALUES RANGING FROM NEARLY 1.20 INCHES ACROSS SE
COCHISE COUNTY TO ABOUT 0.60 INCH ACROSS FAR WRN PIMA COUNTY.
11/00Z NAM/GFS/ECMWF REMAINED SIMILAR VERSUS PREVIOUS SOLUTIONS IN
MOVING THE MOISTURE GRADIENT FURTHER WWD TODAY...AND GENERALLY
BISECTING THIS FORECAST AREA FROM TUCSON EWD WITH DEEPER MOISTURE
FROM MUCH DRIER AIR ACROSS WRN SECTIONS. 11/06Z RUC HRRR DEVELOPS
PRECIP ECHOES BY 18Z ACROSS THE CATALINA/RINCON/SANTA RITA MTNS NEAR
TUCSON...AS WELL AS ACROSS MUCH OF THE REST OF SANTA CRUZ COUNTY...
AND ACROSS THE HIGHER TERRAIN OF SRN GRAHAM/COCHISE COUNTIES.
FOR TODAY...NO SIGNIFICANT ADJUSTMENTS WERE MADE TO THE INHERITED
GRIDDED DATA POP FIELDS. THUS...SCATTERED SHOWERS/TSTMS FROM TUCSON
EWD/SWD THIS AFTERNOON AND THIS EVENING WITH DRY CONDITIONS ACROSS
WRN PIMA COUNTY. THERE SHOULD BE ENOUGH MOISTURE TO JUSTIFY A SLIGHT
CHANCE OF SHOWERS/TSTMS LATE TONIGHT ACROSS THE WHITE MOUNTAINS WITH
DRY CONDITIONS ELSEWHERE.
MONDAY-WEDNESDAY...DEEPER MOISTURE IS PROGGED TO MOVE WELL EAST AND
SOUTH OF SE AZ AS GENERALLY SWLY FLOW ALOFT PREVAILS. ISOLATED-
SCATTERED AFTERNOON/EVENING TSTMS MOSTLY EAST OF TUCSON MONDAY...
THEN ISOLATED AFTERNOON/EVENING TSTMS TUE-WED MAINLY NEAR THE
MOUNTAINS OF GREENLEE/GRAHAM/COCHISE COUNTIES WITH DRY CONDITIONS
ELSEWHERE.
THURSDAY-SATURDAY...UPPER RIDGE TO AMPLIFY OVER THE WRN CONUS AS
HIGH PRESSURE ALOFT BECOMES CENTERED OVER THIS FORECAST AREA. SOME
INCREASE IN MOISTURE IS PROGGED TO OCCUR THIS PERIOD. HOWEVER...
INCREASED MID-LEVEL TEMPS MAY BE A LIMITING FACTOR FOR CONVECTIVE
DEVELOPMENT. FOR CONTINUITY...HAVE MAINTAINED ISOLATED-SCATTERED
AFTERNOON AND EVENING SHOWERS/TSTMS MAINLY FROM TUCSON EWD/SWD.
HIGH TEMPS THIS WEEK WILL AVERAGE ABOUT 2-5 DEGS F ABOVE NORMAL.
&&
.AVIATION...TSRA/SHRA TO DEVELOP FROM KTUS VICINITY EWD/SWD AROUND
17Z-18Z THIS MORNING. SCT TSRA/SHRA TO THEN OCCUR FROM KTUS EWD/SWD
THIS AFTERNOON AND THIS EVENING. EXPECT MVFR CONDITIONS AND WIND
GUSTS TO AROUND 45 KTS WITH THE STRONGEST TSRA. BULK OF PRECIP TO BE
LIMITED TO THE WHITE MTNS NE OF KSAD 06Z-12Z MONDAY. OTHERWISE...
MOSTLY CLEAR SKIES WEST OF KTUS WITH SCT-OVC CLOUDS MOSTLY AT 8-12K
FT AGL FROM KTUS EWD/SWD THRU EARLY MONDAY MORNING OR 12/12Z.
SURFACE WIND GENERALLY LESS THAN 10 KTS THRU EARLY MONDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED THUNDERSTORMS WILL OCCUR FROM TUCSON
EASTWARD AND SOUTHWARD THIS AFTERNOON AND THIS EVENING. THERE WILL
BE DECREASING CHANCES FOR THUNDERSTORMS MONDAY THROUGH WEDNESDAY AS
DEEPER MOISTURE MOVES EAST OF THE AREA. THEREAFTER...ISOLATED TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL PREVAIL THURSDAY
THROUGH SATURDAY. OTHERWISE...NORMAL DIURNAL WIND TRENDS WILL OCCUR
THIS WEEK...WITH OCCASIONAL GUSTS DURING THE AFTERNOON AND EARLY
EVENING HOURS DUE TO STRONG DAYTIME HEATING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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BF
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
136 PM PDT SUN AUG 11 2013
.DISCUSSION...AS OF 1:36 PM PDT SUNDAY...AN UPPER TROUGH OFF THE
CA COASTLINE CONTINUED TO DOMINATE THE WEATHER PATTERN...WITH
MODERATE ONSHORE FLOW AND ABUNDANT STRATUS OFFSHORE. IN FACT...THE
ONSHORE GRADIENT ACTUALLY STRENGTHENED THIS AFTERNOON COMPARED TO
YESTERDAY AFTERNOON...RESULTING IN COOLER TEMPERATURES ALONG THE
COAST. AT THE SAME TIME...A VERY SUBTLE WARMING TREND OCCURRED
INLAND...WITH TEMPERATURES RANGING FROM THE 70S TO MID 80S
INLAND. THESE TEMPERATURES ARE STILL ABOUT 5 TO 10 DEGREES BELOW
NORMAL FOR THE MIDDLE OF AUGUST.
ANOTHER TYPICAL EVENING IS IN STORE FOR THE REGION...AS THE MARINE
LAYER REMAINS AROUND 1500 FEET...WITH PATCHY COASTAL DRIZZLE
POSSIBLE AGAIN LATE TONIGHT/EARLY MONDAY MORNING. BOTH THE NAM AND
HRRR INDICATE ISOLATED AREAS OF 0.01" TO 0.02" UP AND DOWN THE
COASTLINE. THE NAM AND HRRR CONTINUE TO VERIFY WELL WITH REGARDS
TO DRIZZLE...SO IT WAS ADDED TO THE ENTIRE COASTLINE.
A WARMING TREND WILL CONTINUE MONDAY INTO THE MIDDLE OF NEXT WEEK
AS AN UPPER LEVEL RIDGE SETS UP OVER THE FOUR CORNERS REGION WITH
HIGH PRESSURE NUDGING WEST INTO CA. 850 MB TEMPERATURES ARE
FORECAST TO RISE FROM THE 17 DEGREES C RANGE MONDAY AFTERNOON...TO
BETWEEN 21 AND 23 DEGREES C BY WEDNESDAY AFTERNOON. THIS WILL
RESULT IN DAYTIME HIGH TEMPERATURES CLIMBING INTO THE 80S TO MID
90S INLAND...NEAR NORMAL FOR THE MIDDLE OF AUGUST. TEMPERATURES
ALONG THE COAST WILL REMAIN MILD...AS COASTAL LOW CLOUDS WILL BE
PRESENT EACH NIGHT INTO THE MORNING HOURS...WITH TEMPERATURES
MAINLY IN THE 60S.
BY THURSDAY...A SIGNIFICANT UPPER LEVEL LOW WILL MOVE EAST TOWARD
THE PAC NW COASTLINE...WITH AN UPPER TROUGH DIGGING SOUTH AND
IMPACTING THE CA COAST. THIS WILL RESULT IN A DEEPENING MARINE
LAYER...STRONGER ONSHORE FLOW...AND A COOLING TREND INTO AT LEAST
FRIDAY.
OTHERWISE...NO MAJOR CHANGES TO THE FORECAST...WITH A PERSISTENT
DRY WEATHER PATTERN AND SUBTLE VARIATIONS WITH REGARDS TO THE
MARINE LAYER AND TEMPERATURE FORECAST.
&&
.AVIATION...AS OF 10:40 AM PDT SUNDAY...MARINE LAYER DEPTH
CONTINUES AROUND 1500 FEET AND MOST TERMINALS ARE STILL AFFECTED
BY LOW STRATUS CEILINGS. EXPECT CLEARING WITHIN THE NEXT HOUR OR
TWO. AFTERNOON SEABREEZE WINDS EXPECTED ONCE AGAIN.
VICINITY OF KSFO...MVFR CIGS UNTIL 19-20Z. WEST WIND GUSTS TO 20-22
KNOTS BEGINNING 21Z TODAY. EARLY CIG RETURN TONIGHT BY 03Z.
KSFO BRIDGE APPROACH...MVFR CIGS CLEARING BEFORE SFO. SOUTH PART
OF BAY IS ALREADY CLEAR...EXPECT VFR BY 19Z.
MONTEREY BAY AREA TERMINALS...IFR CIGS TIL 20Z. EARLY RETURN OF
LOW CLOUDS BY 02Z.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: RILEY
AVIATION/MARINE: SIMS
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AREA FORECAST DISCUSSION
NWS BOISE ID
906 AM MDT SUN AUG 11 2013
.DISCUSSION...MADE SOME MINOR UPDATES TO BOOST POPS IN NORTHERN
PORTION OF FORECAST AREA INCLUDING BAKER COUNTY OREGON...THE
WEST CENTRAL MOUNTAINS AND NORTHERN BOISE MOUNTAINS IN IDAHO.
THESE AREAS NOW LOOK LIKE A GOOD BET TO SEE SCATTERED
THUNDERSTORMS THIS AFTERNOON AND EVENING. THIS THINKING IS
SUPPORTED BY OBSERVATIONS...MODEL DATA AND SATELLITE IMAGERY. THE
12Z SOUNDING AT BOISE IS MORE MOIST TODAY AND PROJECTED TO BE MORE
UNSTABLE IN THE AFTERNOON THAN YESTERDAY. EARLY MORNING VISIBLE
SATELLITE IMAGERY ALREADY SHOWS LOTS OF CUMULUS CLOUDS IN EASTERN
OREGON AND IN IDAHO. THE 12Z RUNS OF THE NAM AND HRRR MODELS SHOW
SCATTERED CONVECTION BREAKING OUT AROUND 21Z. THE MAIN THREAT WITH
THESE THUNDERSTORMS WILL BE LIGHTNING AND GUSTY WINDS WHICH COULD
LEAD TO ADDITIONAL FIRE STARTS IN THE FORESTS. DRIER AIR IN NEVADA
SHOULD MOVE INTO SOUTHERN OREGON AND SOUTHERN IDAHO TODAY FOR
MOSTLY SUNNY AND HOT WEATHER THERE. SOUTHERLY WINDS SHOULD
CONTINUE TO BLOW WILD FIRE SMOKE TOWARDS THE NORTH TODAY...KEEPING
THE TREASURE AND MAGIC VALLEYS RELATIVELY SMOKE FREE WHILE
BRINGING DENSE SMOKE TO MCCALL...DONNELLY...IDAHO CITY...CASCADE AND
OTHER AREAS IN THE WEST CENTRAL MOUNTAINS OF IDAHO.
&&
AVIATION...WIDESPREAD SMOKE LAYERS ALOFT THROUGH MONDAY...CAUSING
AREAS OF TERRAIN OBSCURATION IN THE BOISE AND W CENTRAL IDAHO
MOUNTAINS...WITH MVFR AND LOCAL IFR CONDITIONS IN THE VALLEYS UNTIL
18Z AND AFTER 06Z MONDAY. AFTER 18Z...ISOLATED THUNDERSTORMS
...EXCEPT SCATTERED THUNDERSTORMS OVER N HARNEY AND W BAKER
COUNTIES AS WELL AS N OF A LINE FROM ONTARIO OREGON TO IDAHO CITY
IDAHO. SURFACE WINDS...LIGHT EXCEPT NEAR THUNDERSTORMS. WINDS
ALOFT...SOUTH AVERAGING 12 KTS AT 10K FEET MSL.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH MONDAY...UPPER LOW CENTERED ALONG THE
OREGON COAST WILL DRIFT SLOWLY NORTHWARD REACHING THE WASHINGTON
COAST TONIGHT AND MONDAY. THERE IS SOME MOISTURE AVAILABLE ACROSS SE
OREGON AND SW IDAHO FOR CONVECTION. PWAT/S ARE AROUND 0.75 INCHES
THROUGH MONDAY...WHICH IS SLIGHTLY ABOVE NORMAL. THERE IS ALSO SOME
WEAK UPPER LEVEL SUPPORT FOR CONVECTION DUE TO OUR PROXIMITY TO THE
UPPER LOW. DAYTIME HEATING WILL INITIATE CONVECTION THIS
AFTERNOON...WITH ISOLATED SHOWERS AND THUNDERSTORMS DEVELOPING
ACROSS SE OREGON AND THE HIGHER TERRAIN OF SW IDAHO. THUNDERSTORMS
WILL BE SCATTERED IN BAKER COUNTY. SOUTHERLY FLOW THIS AFTERNOON
WILL BRING DENSE SMOKE FROM FIRES IN ELMORE AND CAMAS COUNTY
NORTHWARD INTO THE BOISE/WEST CENTRAL MTNS. THE SMOKE MAY BE DENSE
ENOUGH TO INHIBIT HEATING THUS LIMITING CONVECTION. PWAT/S OF AROUND
0.75 INCHES AND THE OVERALL PATTERN OF SW FLOW ALOFT WILL CONTINUE
THROUGH MONDAY SO EXPECT A REPEAT OF AFTERNOON CONVECTION...WITH
SLIGHT CHANCE OF SHOWERS AND STORMS IN SE OREGON AND THE HIGHER
TERRAIN OF SW IDAHO. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL.
WINDS WILL BE LIGHT... EXCEPT GUSTY IN THE VICINITY OF
THUNDERSTORMS.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY...MODELS AGREE THAT THE
WARM UPPER LEVEL RIDGE WILL GAIN STRENGTH AND SHIFT WEST TUESDAY AND
WEDNESDAY. THIS WILL BRING GRADUAL WARMING THROUGH THURSDAY AND A
DECREASING CHANCE OF THUNDERSTORMS...WITH ANY CONVECTION CONFINED TO
THE NORTHERN EDGE OF OUR CWA. TEMPERATURES WILL AVERAGE ABOUT 5
DEGREES ABOVE NORMAL. MODELS ARE STARTING TO HINT AT A PATTERN
CHANGE BY THE END OF THE WEEK...WITH THE NORTH PORTION OF THE RIDGE
SHIFTING EAST OF THE ROCKIES ON FRIDAY ALLOWING MORE PROGRESSIVE
WESTERLY FLOW ALOFT TO REACH IDAHO AND THE NORTHERN ROCKIES ON
SATURDAY. THIS WOULD MEAN CONTINUED DRY WEATHER WITH TEMPERATURES
POSSIBLY COOLING A FEW DEGREES NEXT WEEKEND.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...RED FLAG WARNING FROM 3 PM THIS AFTERNOON TO 9 PM MDT THIS
EVENING IDZ401>403.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...JB
AVIATION.....VM
PREV SHORT TERM...BW
PREV LONG TERM....MT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
518 PM CDT SUN AUG 11 2013
.DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* E-W LINE OF SCATTERED SHOWERS...POSSIBLE ISOLATED THUNDER NEXT
FEW HOURS
* POTENTIAL FOR SOME VARIABILITY IN WINDS IN VICINITY OF SHOWERS
* MORE WIDESPREAD SHOWERS AND POSSIBLE THUNDER AFTER MIDNIGHT
ALLSOPP
//DISCUSSION...UPDATED 22Z...
LINE OF SCATTERED SHOWERS HAS DEVELOPED IN AN EAST-WEST BAND FROM
FEP TO RFD TO NEAR PWK. SHOWERS MOVING JUST S OF DUE EAST AND WILL
REMAIN MOSTLY NORTH OF ORD. VERY LITTLE INSTABILITY OVER NORTHEAST
IL...WITH BETTER INSTABILITY OVER WESTERN IL INTO IA. ISOLATED
THUNDER NOT OUT OF THE QUESTION BUT CHANCES OF THUNDER APPEAR LOW
THE NEXT FEW HOURS. OUTFLOW FROM A STRONGER SHOWER COULD CAUSE
SOME FLUCTUATION IN WIND SPEED AND DIRECTION AT RFD AND ORD THE
NEXT FEW HOURS.
WEAK LAKE BREEZE HAS STALLED AND APPEARS TO BE RETREATING TO THE
EAST. EXPECT THIS TREND TO CONTINUE.
ALLSOPP
PREVIOUS DISCUSSION...18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OVER WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM TO HIGH CONFIDENCE IN LAKE BREEZE STAYING EAST OF
ORD/MDW.
* MEDIUM TO HIGH CONFIDENCE IN WIND REMAINING SOUTHWEST BUT
OUTFLOW FROM SHOWERS COULD BRIEFLY CAUSE WIND TO FLUCTUATE TO
NW.
* MEDIUM CONFIDENCE IN TIMING OF ADDITIONAL SHOWERS AND ISOLATED
THUNDER LATE TONIGHT.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
330 PM CDT
AS HIGH PRESSURE CENTERED OVER THE CENTRAL GREAT LAKES SHIFTS
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT...A GENERAL SOUTHERLY
DIRECTION CAN BE EXPECTED ACROSS THE LAKE. ALTHOUGH...A WEAK
TROUGH OF LOW PRESSURE WILL MOVE EAST THROUGH ONTARIO AND THE
NORTHERN GREAT LAKES WITH WINDS THEN EXPECTED TO BEGIN SHIFTING TO
THE WEST LATE TONIGHT. AS THIS TROUGH EXITS TO THE EAST AND HIGH
PRESSURE BUILDS SOUTH OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY AND MONDAY NIGHT...WINDS WILL TURN MORE NORTHERLY ON MONDAY
WHILE INCREASING. NORTHERLY WINDS AND WAVES WILL CONTINUE TO
INCREASE/BUILD MONDAY NIGHT INTO TUESDAY...WITH WAVES HAZARDOUS TO
SMALL CRAFT POSSIBLE ACROSS BOTH THE ILLINOIS AND INDIANA
NEARSHORE WATERS TUESDAY/TUESDAY NIGHT. WINDS AND WAVES WILL BEGIN
TO DIMINISH LATER TUESDAY NIGHT INTO WEDNESDAY...AS HIGH PRESSURE
SETTLES BACK IN.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
330 PM CDT SUN AUG 11 2013
.DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
BRIEF PERIOD OF VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
330 PM CDT
AS HIGH PRESSURE CENTERED OVER THE CENTRAL GREAT LAKES SHIFTS
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT...A GENERAL SOUTHERLY
DIRECTION CAN BE EXPECTED ACROSS THE LAKE. ALTHOUGH...A WEAK
TROUGH OF LOW PRESSURE WILL MOVE EAST THROUGH ONTARIO AND THE
NORTHERN GREAT LAKES WITH WINDS THEN EXPECTED TO BEGIN SHIFTING TO
THE WEST LATE TONIGHT. AS THIS TROUGH EXITS TO THE EAST AND HIGH
PRESSURE BUILDS SOUTH OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY AND MONDAY NIGHT...WINDS WILL TURN MORE NORTHERLY ON MONDAY
WHILE INCREASING. NORTHERLY WINDS AND WAVES WILL CONTINUE TO
INCREASE/BUILD MONDAY NIGHT INTO TUESDAY...WITH WAVES HAZARDOUS TO
SMALL CRAFT POSSIBLE ACROSS BOTH THE ILLINOIS AND INDIANA
NEARSHORE WATERS TUESDAY/TUESDAY NIGHT. WINDS AND WAVES WILL BEGIN
TO DIMINISH LATER TUESDAY NIGHT INTO WEDNESDAY...AS HIGH PRESSURE
SETTLES BACK IN.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
310 PM CDT SUN AUG 11 2013
.DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
BRIEF PERIOD OF VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
//PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
BRIEF PERIOD OF VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1254 PM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
//PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LAKE BREEZE THIS AFTN WILL SHIFT WINDS TO THE SE. WINDS ARE
EXPECTED TO REMAIN LIGHT AROUND 5 KT.
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE.
* HIGH CONFIDENCE IN LIGHT SE WINDS BEHIND THE LAKE BREEZE.
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1127 AM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
//PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* LAKE BREEZE THIS AFTN WILL SHIFT WINDS TO THE SE. WINDS ARE
EXPECTED TO REMAIN LIGHT AROUND 5 KT.
* SLIGHT CHANCE OF SHRA/TSRA LATE THIS EVENING WITH A BETTER
CHANCE OF SHRA/TSRA LATE TONIGHT INTO MONDAY MORNING.
JEE
//DISCUSSION...UPDATED 16Z...
MADE SOME ADJUSTMENTS BASED ON CURRENT TRENDS AND LATEST GUIDANCE.
WINDS HAVE TURNED EAST ALONG THE LAKESHORE BUT THINKING THE WINDS
WILL BE MORE SE WHEN THE LAKE BREEZE MOVES THROUGH THE EASTERN
TERMINALS. ALSO THINKING THE SE WINDS WILL BE LIGHT AROUND 5 KT AS
THE DOWNTOWN OB HAS BEEN STEADY ARND 5 KT SINCE THE WIND TURNED
EAST.
LOOKING AT PRECIP TODAY...THINKING THE VAST MAJORITY OF SHRA/TSRA
WILL REMAIN NORTH OF THE TERMINALS ALONG THE STATIONARY BOUNDARY
OVER SOUTHERN WI. GUIDANCE DOES SUGGEST THE LINE MAY SINK SOUTH A
BIT WITH SHRA IN THE VICINITY OF RFD LATE THIS AFTN...THEREFORE
PUT A VCSH IN AT RFD AFT 20Z. GUIDANCE HAS THE FRONT
SINKING SOUTH A BIT LATER SO PUSHED CHANCES OF PRECIP BACK A FEW
HOURS. RFD WILL BE IMPACTED FIRST. NOT SURE HOW MUCH INSTABILITY
WILL BE AROUND SO WENT WITH A HIGHER CHANCE OF SHRA THAN TS...BUT
CANNOT COMPLETELY RULE TS OUT AT RFD. FOR THE EASTERN
TERMINALS...SHRA MAY ARRIVE EVEN LATER THAN CURRENTLY INDICATED BUT
DECIDED TO PUSH THE PRECIP BACK INCREMENTALLY.
PREVIOUS DISCUSSION...12Z...
TRICKY FORECAST THIS MORNING IN TERMS OF SHRA/TSRA CHANCES AND
WIND DIRECTION TRENDS. HIGH PRESSURE REMAINS OVER THE AREA BUT
WILL BE SLIDING SOUTHEASTWARD THROUGH THE DAY AS A COOL FRONTAL
BOUNDARY DROPS SOUTHWARD FROM ONTARIO AND EVENTUALLY CROSSES THE
AREA MONDAY. IN THE MEANTIME...AN UPPER LEVEL DISTURBANCE AND
ASSOCIATED MID LEVEL WARM ADVECTION GENERATED A SMALL SHRA/TSRA
COMPLEX WHICH IS NOW SHOWING SIGNS OF DECAY OVER NORTH-CENTRAL
IOWA. THIS WILL BE THE FIRST CHANCE FOR SHRA AT THE TERMINALS BUT
THERE MAY NOT BE MUCH LEFT OF IT BY MID MORNING WHICH IS WHEN IT
WOULD ARRIVE AT RFD. HAVE RETAINED VCSH MENTION AT RFD TO ACCOUNT
FOR THE POTENTIAL FOR SOME LIGHT RAIN OR SPRINKLES. SHOULD THIS
PRECIP HOLD TOGETHER IT WOULD REACH THE CHI AREA TERMINALS TOWARD
MIDDAY BUT HAVE A HARD TIME SEEING MUCH MORE THAN SOME LIGHT RAIN
OR SPRINKLES BY THEN. WARM ADVECTION WILL REMAIN IN PLACE ALOFT
WHICH MAY HELP TRIGGER SOME ISOLD/SCT DEVELOPMENT THIS AFTERNOON
BUT AM THINKING THAT THE BETTER CHANCES WILL ARRIVE THIS EVENING
AND EARLY TONIGHT AS THE LOW LEVEL JET INTENSIFIES TO THE WEST.
WILL CONTINUE WITH PROB30 FOR TS DURING THE EVENING HOURS WITH
SOME ACTIVITY POSSIBLE...BUT IT APPEARS THE BULK OF ANY ACTIVITY
WILL BE NORTH OF THE WISCONSIN BORDER. ADDITIONAL CHANCES WILL BE
IN PLACE MONDAY AS THE AFOREMENTIONED COLD FRONT CROSSES THE AREA
BUT THE EXTENT OF THE ACTIVITY WILL LIKELY DEPEND ON HOW ACTIVITY
EVOLVES TONIGHT SO WILL KEEP THE LATER PART OF THE 30 HR ORD TAF
DRY. THE FRONT MAY SLOW SO HAVE OPTED TO KEEP A SOUTHWEST WIND
MONDAY MORNING.
IN TERMS OF WINDS...WITH THE HIGH OVERHEAD MOST LOCATIONS HAVE
BEEN CALM OVERNIGHT WITH A FEW SITES STARTING TO REGISTER SOME
LIGHT WINDS. EXPECT A WEST TO WEST-NORTHWEST DIRECTION THIS
MORNING WITH SPEEDS REMAINING QUITE LIGHT. A LAKE BREEZE IS
EXPECTED TO DEVELOP LATE THIS MORNING AND MOVE INLAND TURNING
WINDS EASTERLY AND WILL CONTINUE WITH THE IDEA OF IT CROSSING
ORD/MDW LATER THIS AFTERNOON. THIS WILL NEED TO BE WATCHED CLOSELY
THOUGH BECAUSE AN INFLUX OF CLOUD COVER COULD PREVENT ITS
DEVELOPMENT AS COULD ANY SORT OF OUTFLOW FROM THE DECAYING
SHRA/TSRA COMPLEX. WINDS THEN TURN SOUTH TO SOUTHEAST THIS EVENING
RETURNING TO SOUTHWEST OVERNIGHT AS THE PRESSURE GRADIENT
TIGHTENS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE.
* HIGH CONFIDENCE IN LIGHT SE WINDS BEHIND THE LAKE BREEZE.
* MEDIUM CONFIDENCE IN DRY CONDITIONS THROUGH THIS AFTN AND TIMING
OF SHRA/TSRA LATE TONIGHT/MONDAY MORNING. SHRA/TSRA MAY ARRIVE
EVEN LATER.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1044 AM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
&&
.PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LAKE BREEZE PSBL THIS AFTN. WIND SHIFT FROM LIGHT WEST OR
SOUTHWEST TO LIGHT EASTERLY.
* LOW CHANCE FOR SCATTERED SHRA/TSRA THIS AFTERNOON...BUT SOMEWHAT BETTER
CHANCES FAVORED MID/LATE EVENING AND EARLY TONIGHT.
JEE
//DISCUSSION...UPDATED 12Z...
TRICKY FORECAST THIS MORNING IN TERMS OF SHRA/TSRA CHANCES AND
WIND DIRECTION TRENDS. HIGH PRESSURE REMAINS OVER THE AREA BUT
WILL BE SLIDING SOUTHEASTWARD THROUGH THE DAY AS A COOL FRONTAL
BOUNDARY DROPS SOUTHWARD FROM ONTARIO AND EVENTUALLY CROSSES THE
AREA MONDAY. IN THE MEANTIME...AN UPPER LEVEL DISTURBANCE AND
ASSOCIATED MID LEVEL WARM ADVECTION GENERATED A SMALL SHRA/TSRA
COMPLEX WHICH IS NOW SHOWING SIGNS OF DECAY OVER NORTH-CENTRAL
IOWA. THIS WILL BE THE FIRST CHANCE FOR SHRA AT THE TERMINALS BUT
THERE MAY NOT BE MUCH LEFT OF IT BY MID MORNING WHICH IS WHEN IT
WOULD ARRIVE AT RFD. HAVE RETAINED VCSH MENTION AT RFD TO ACCOUNT
FOR THE POTENTIAL FOR SOME LIGHT RAIN OR SPRINKLES. SHOULD THIS
PRECIP HOLD TOGETHER IT WOULD REACH THE CHI AREA TERMINALS TOWARD
MIDDAY BUT HAVE A HARD TIME SEEING MUCH MORE THAN SOME LIGHT RAIN
OR SPRINKLES BY THEN. WARM ADVECTION WILL REMAIN IN PLACE ALOFT
WHICH MAY HELP TRIGGER SOME ISOLD/SCT DEVELOPMENT THIS AFTERNOON
BUT AM THINKING THAT THE BETTER CHANCES WILL ARRIVE THIS EVENING
AND EARLY TONIGHT AS THE LOW LEVEL JET INTENSIFIES TO THE WEST.
WILL CONTINUE WITH PROB30 FOR TS DURING THE EVENING HOURS WITH
SOME ACTIVITY POSSIBLE...BUT IT APPEARS THE BULK OF ANY ACTIVITY
WILL BE NORTH OF THE WISCONSIN BORDER. ADDITIONAL CHANCES WILL BE
IN PLACE MONDAY AS THE AFOREMENTIONED COLD FRONT CROSSES THE AREA
BUT THE EXTENT OF THE ACTIVITY WILL LIKELY DEPEND ON HOW ACTIVITY
EVOLVES TONIGHT SO WILL KEEP THE LATER PART OF THE 30 HR ORD TAF
DRY. THE FRONT MAY SLOW SO HAVE OPTED TO KEEP A SOUTHWEST WIND
MONDAY MORNING.
IN TERMS OF WINDS...WITH THE HIGH OVERHEAD MOST LOCATIONS HAVE
BEEN CALM OVERNIGHT WITH A FEW SITES STARTING TO REGISTER SOME
LIGHT WINDS. EXPECT A WEST TO WEST-NORTHWEST DIRECTION THIS
MORNING WITH SPEEDS REMAINING QUITE LIGHT. A LAKE BREEZE IS
EXPECTED TO DEVELOP LATE THIS MORNING AND MOVE INLAND TURNING
WINDS EASTERLY AND WILL CONTINUE WITH THE IDEA OF IT CROSSING
ORD/MDW LATER THIS AFTERNOON. THIS WILL NEED TO BE WATCHED CLOSELY
THOUGH BECAUSE AN INFLUX OF CLOUD COVER COULD PREVENT ITS
DEVELOPMENT AS COULD ANY SORT OF OUTFLOW FROM THE DECAYING
SHRA/TSRA COMPLEX. WINDS THEN TURN SOUTH TO SOUTHEAST THIS EVENING
RETURNING TO SOUTHWEST OVERNIGHT AS THE PRESSURE GRADIENT
TIGHTENS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM LOW CONFIDENCE IN LAKE BREEZE DEVELOPING AND CROSSING THE
TERMINALS THIS AFTERNOON.
* MEDIUM CONFIDENCE IN LOW CHANCE FOR SHRA/TSRA THROUGH THE
AFTERNOON THEN INCREASING CHANCES MID/LATE EVENING.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
133 AM EDT SUN AUG 11 2013
.SYNOPSIS...
ISSUED AT 133 AM EDT SUN AUG 11 2013
HIGH PRESSURE WILL MAINTAIN DRY CONDITIONS THROUGHOUT THE DAY
TODAY. NEXT CHANCE OF SHOWERS AND THUNDERSTORMS WILL ARRIVE IN THE
EARLY HOURS OF MONDAY MORNING AS A LOW PRESSURE SYSTEM MOVES
THROUGH THE REGION.
&&
.UPDATE...
ISSUED AT 827 PM EDT SAT AUG 10 2013
DEPARTING SHEARED VORTICITY MAXIMUM ACROSS THE NORTHERN GREAT LAKES
AND DIURNAL WANING OF SURFACE BASED INSTABILITY WILL RESULT IN
CONTINUED DOWNWARD TREND OF ISOLATED SHOWERS ACROSS THE EXTREME
SOUTHEAST EARLY THIS EVENING. WATER VAPOR IMAGERY EARLY THIS
EVENING AND 22Z RAP INITIALIZATION DOES SEEM TO SUGGEST PRESENCE OF
WEAK UPSTREAM SHORT WAVE ACROSS NORTHWEST ILLINOIS. APPROACH OF
THIS WEAK WAVE LATE THIS EVENING AND CONTINUED WEAK SFC
CONVERGENCE WITH LINGERING INVERTED TROUGH TYPE FEATURE COULD
ALLOW FOR AN ISOLATED SHOWER TO DEVELOP ACROSS EASTERN PORTIONS OF
THE AREA. HOWEVER...HAVE LARGELY MAINTAINED PREVIOUS FORECAST
TRENDS TO MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS WITH CLOUDS
PERSISTING OVER THE NEXT FEW HOURS...ESPECIALLY IN VICINITY OF
AFOREMENTIONED SFC CONVERGENCE ZONE FROM ROUGHLY ANGOLA TO SOUTH
OF FORT WAYNE. WILL ALSO NEED TO MONITOR TRENDS THROUGH REMAINDER
OF EVENING FOR SOME PATCHY FOG POTENTIAL...PARTICULARLY ACROSS
SOUTHEAST PORTIONS OF THE AREA WHERE LOW LEVEL MOISTURE WILL
LIKELY LINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 447 PM EDT SAT AUG 10 2013
WK LL CVRG BNDRY IN ASSOCN/W SHEARING DISTURBANCE ALOFT AND IN
CONJUNCTION W/SUFFICIENT SFC BASED DESTABILIZATION ENOUGH TO SPARK A
NARROW BKN BAND OF SHRA ALG A HUNTING TO DEFIANCE LINE THIS AFTN.
ACTIVITY LIKELY NR PEAK AND XPC A GENERAL DOWNTREND THROUGH 23Z.
OTRWS SFC RIDGING TO EXPAND EWD ACRS THE GREAT LAKES IN BEHIND
SECONDARY WK CDFNT PASSING THROUGH THE LAKES TONIGHT YIELDING A
PLEASANTLY COOL AND DRY SUNDAY.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 447 PM EDT SAT AUG 10 2013
A WEAK UPPER LEVEL TROF AND ACCOMPANYING COLD FRONT WILL MOVE SOUTH
ACROSS THE WESTERN GREAT LAKES REGION LATE SUNDAY NIGHT...AND TOWARD
THE OHIO RIVER MONDAY NIGHT. HAVE EXPANDED SHOWER/STORM CHANCES LATE
SUNDAY NIGHT OVER NORTHERN AREAS AS A SURGE OF LOW LEVEL THETA E
REACHES FAR SOUTHERN LOWER MICHIGAN INTO NRN INDIANA. PREFER THE
ECMWF HANDLING THIS SYSTEM...WITH CONVECTIVE DEVELOPMENT IN THE AREA
OF THIS LOW LEVEL THETA E CONVERGENCE OVER LOWER MICHIGAN...AND THEN
MONDAY NIGHT WITH REDEVELOPMENT ALONG THE THE FRONT OVER NRN INDIANA
INTO NW OHIO. HAVE RAISED SHOWER/STORM CHANCES ACCORDINGLY LATE
SUNDAY NIGHT. HAVE ALSO WENT WITH A LITTLE SLOWER FRONTAL PASSAGE
MONDAY NIGHT...WITH SOME LINGERING SHOWERS POSSIBLE OVER SOUTHEAST
AREAS LATE MONDAY NIGHT. NOT OPTIMAL SEVERE STORM PARAMETERS WITH
RELATIVELY LOW CAPES AND LOW LEVEL WINDS MORE UNIDIRECTIONAL.
HOWEVER...THE RIGHT ENTRANCE REGION OF A DEPARTING 80 JET MAX MAY BE
SUFFICIENT TO PRODUCE SOME STRONG STORMS. OTHERWISE...KEPT THE
FORECAST DRY FROM TUESDAY THROUGH THE END OF THE FORECAST PERIOD
SATURDAY. HAVE BLENDED THE GFS AND ECMWF RUNS OVER THIS PERIOD...
WITH THE THERMAL TROF REMAINING OVER THE AREA LONGER THAN EARLIER
MODEL RUNS INDICATED. AS A RESULT...HAVE TRENDED MOST HIGH AND LOW
TEMPS DOWN STARTING WEDNESDAY NIGHT. THIS PATTERN IS MORE LIKE
SEPTEMBER THAN AUGUST...WITH HIGHS IN THE MID TO UPPER 70S AND LOWS
MAINLY IN THE 50S. THE GFS MEAN ENSEMBLE MOS APPEARS ON TRACK...SO
HAVE ATTEMPTED TO FOLLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 133 AM EDT SUN AUG 11 2013
SURFACE HIGH PRESSURE WILL MAINTAIN LIGHT WINDS AND VFR CONDITIONS
FOR MUCH OF THE FORECAST PERIOD. RESIDUAL NEAR SURFACE MOISTURE
AROUND KFWA MAY SUPPORT SOME BRIEF BR DEVELOPMENT LATER THIS
MORNING BUT AREA DEWPOINTS ARE FAIRLY LOW WITH NO VIS REDUCTION AS
OF YET. WILL MAINTAIN MVFR MENTION BUT ANY PATCHY FOG THAT
DEVELOPS SHOULD BE SHALLOW WITH LIMITED AVIATION IMPACT. ALONG
WITH SOME SCT DIURNAL CU...MIDLEVEL CLOUDS WILL BE INCREASING
TOWARD THE END OF THE DAY AS THE NEXT SYSTEM APPROACHES BUT
CEILINGS EXPECTED TO REMAIN WELL WITHIN VFR CATEGORY THROUGH THE
PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...KG/AGD
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...AGD
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1225 PM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 1216 PM CDT SUN AUG 11 2013
IT HAS RAINED LITTLE MORE THAN A FEW ISOLATED SPRINKLES THUS FAR
TODAY...AND IT APPEARS THERE IS LITTLE THREAT FOR ANYTHING MORE
THAN THIS UNTIL MID AFTERNOON. I HAVE DONE SEVERAL UPDATES TO
REDUCE POPS NORTH...AND UNTIL WE SEE NEW CONVECTION FORMING
NORTHERN IOWA...WE MAY NEED MORE UPDATES TO DRY THE FORECAST OUT
MORE SO. TEMPERATURES HAVE BEEN BUMPED UP TO LOWER TO MID 80S IN
MOST LOCATIONS GIVEN THE LACK OF DENSE PERSISTENT CLOUD COVER
SOUTH OF HIGHWAY 20.
ERVIN
&&
.SYNOPSIS...
ISSUED AT 305 AM CDT SUN AUG 11 2013
06Z SFC ANALYSIS HAS A WEAK LOW NEAR KICR WITH A STATIONARY FRONT
SOUTHEAST INTO WESTERN IOWA. A WEAK BOUNDARY RAN FROM SOUTHEAST
SOUTH DAKOTA INTO NORTHERN IOWA. DEW POINTS WERE IN THE 50S ACROSS
THE GREAT LAKES WITH 60S IN THE PLAINS AND 70S ACROSS THE DEEP SOUTH
AND OHIO VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
THE MCS AND LIFT TOOLS WHEN APPLIED TO TRENDS IN THE RAP AND OTHER
MODELS SUGGEST A MAJORITY OF THE PRECIPITATION WILL REMAIN NORTH OF
THE CWFA THROUGH MID DAY WITH SOME SHOWERS BRUSHING THE NORTHERN
CWFA IN THE HIGHWAY 20 CORRIDOR. RECENT TRENDS WITH THE RAP SUGGEST
PRECIPITATION MAY NOT BEGIN ENTERING THE NORTHERN CWFA UNTIL AROUND
SUNRISE.
PRECIPITATION SHOULD WANE DURING THE LATE MORNING AND EARLY
AFTERNOON BEFORE RE-DEVELOPING THIS AFTERNOON HOURS DURING MAX
HEATING. ANY PRECIPITATION IN THE HWY 20 CORRIDOR WILL EXPAND
SOUTHWARD TO HWY 30 AND EVENTUALLY TO I-80 BY LATE AFTERNOON.
TONIGHT...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE ACROSS
ROUGHLY THE NORTHERN HALF OF THE CWFA DURING THE EVENING BEFORE
SLOWLY SPREADING SOUTH AFTER MIDNIGHT. THE EXTREME SOUTHERN PART OF
THE CWFA CURRENTLY LOOKS TO BE DRY BOTH TODAY AND TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN AUG 11 2013
RAIN CHANCES LINGER EARLY IN THE WEEK THEN MAINLY DRY AND PLEASANT
REST OF THE PERIOD WITH NEAR TO BELOW NORMAL TEMPS.
MON-MON NGT... SURFACE AND 850 MB COLD FRONTS WILL GRADUALLY SLIDE
THROUGH THE AREA AS AN UPPER LEVEL TROUGH MOVES INTO THE GREAT
LAKES. 850 MB BOUNDARY IS SUGGESTED TO BE PRIMARY PCPN MECHANISM
DUE TO BETTER CONVERGENCE WITH SCATTERED ELEVATED SHOWERS AND
ISOLD STORMS MAINLY NORTH OF I-80 MON AM SLIDING SOUTHEAST IN THE
PM. CONVERGENCE ALONG SURFACE FRONT FAIRLY WEAK BUT IF SUFFICIENT
HEATING INTO THE MID 80S THEN CAPPING INVERSION SHOULD WEAKEN AND
JUST ENOUGH CONVERGENCE TO ALLOW SCATTERED STORMS TO DEVELOP FROM
MID PM TO EARLY EVE MAINLY JUST S/SE OF QUAD CITIES. ENVIRONMENT
LOOKS LIKE FAIRLY WEAK TO MARGINAL SHEAR (0-6KM BULK SHEAR 20-25 KTS)
AND MODERATE INSTABILITY (MUCAPES 1500-2000+ J/KG)... THUS MARGINAL
ISOLD PULSE TYPE STORMS SUGGESTED WITH SOME SMALL HAIL AND DOWNBURST
WINDS POSSIBLE. BANKING ON ANY PCPN MAINLY SCATTERED AND ENOUGH
BREAKS IN CLOUDS TO YIELD WIDESPREAD 80S FOR HIGHS WITH THE WARMEST
READINGS ACROSS THE SOUTHERN CWA. RAIN CHCS LINGER MON EVE ACROSS THE
SOUTH...THEN HIGH PRESSURE RIDGE BEGINS TO BUILD IN OVRNGT BRINGING IN
DRIER AIR. LOWS MON NGT COOLEST NORTH WHERE SOME 50S WHILE 60S ARE
LIKELY ELSEWHERE.
TUE-TUE NGT... UKMET IS AN OUTLIER HOLDING UP MID LEVEL BAROCLINIC
ZONE ACROSS SOUTHERN CWA AND GENERATING SOME ADDITIONAL PCPN ON TUE.
HAVE SIDED TOWARD CONSENSUS FCST WITH CONTINUED DRY AND COOL
ADVECTION WITH STRENGTHENING NORTHWEST FLOW ALOFT AND INCOMING SURFACE
RIDGE SHUNTING BAROCLINIC ZONE AND PCPN PROCESSES SOUTH/WEST OF THE
CWA. HIGHS TUE RANGING FROM SOME MID 70S NORTH TO LOWER 80S SOUTH WITH
PT-MOSUNNY SKIES. CONTINUED LOWERING OF DEWPTS MAINLY INTO THE 50S
COUPLED WITH N/NE WINDS 5-10 MPH SHOULD MAKE FOR A REAL NICE AND
VERY COMFORTABLE DAY FOR OUTDOOR ACTIVITIES. COOL CONDITIONS EXPECTED
TUE NGT WITH CLEARING SKIES AND LIGHT WINDS ALLOWING FOR WIDESPREAD
LOWS IN THE 50S.
WED-SAT...FLOW ALOFT WILL REMAIN NORTHWEST WITH LARGE EXPANSE OF HIGH
PRESSURE AT THE SURFACE SLOWLY SHIFTING FROM THE UPPER MIDWEST INTO
THE OH VLY. RESULT WILL BE A PROLONGED PERIOD OF FANTASTIC WX FEATURING
LOW HUMIDITY...LIGHT WINDS...MAINLY CLEAR SKIES AND SLIGHTLY BELOW
NORMAL TEMPS WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN
THE 50S TO AROUND 60F.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1216 PM CDT SUN AUG 11 2013
A WEAK FRONT WILL MOVE THROUGH EASTERN IOWA TODAY...BRINGING A LOW
THREAT FOR SCATTERED SHOWERS. AN ISOLATED STORM CANNOT BE RULED
OUT...BUT THIS THREAT WILL BE TOO LOW TO INCLUDED MENTION IN TAFS.
OTHERWISE...EXPECTED PARTLY TO MOSTLY CLOUDY SKIES THROUGH
TOMORROW...WITH MAINLY MID CLOUDS BETWEEN 5000 FT AND 10000 FT
CIGS. WINDS WILL BE 6 TO 10 KTS FROM THE SOUTHWEST THROUGH SUNSET
TODAY...THEN LIGHT AND VARIABLE OVERNIGHT...AND AFTER 15Z
MONDAY...NORTH WINDS OF 6 TO 10 KTS ARE EXPECTED BEHIND THE WEAK
FRONT. DURING THE PERIOD OF NEARLY CALM WINDS TONIGHT...THERE IS A
LOW THREAT FOR FOG. THIS TREND WILL BE WATCHED CAREFULLY FOR
POTENTIAL MVFR FOG CONDITIONS IF SKIES CAN BE CLEAR AT THE SAME
TIME PERIOD.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
701 AM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 649 AM CDT SUN AUG 11 2013
RADAR TRENDS SHOW THE PRECIPITATION THAT IS/WILL BE SKIRTING THE
NORTHERN CWFA IS MORE SHOWERS THAN STORMS. RAP TRENDS WITH THE
MCS...LIFT...AND HEAVY RAIN TOOLS INDICATE THE CURRENT NOCTURNAL
CONVECTION WILL MOVE THROUGH THE HWY 20 CORRIDOR AND SLOWLY
DISSIPATE AS IT ENCOUNTERS MORE DRY AIR AND MOVES AWAY FROM THE
BETTER SUPPORT.
A LULL IN ACTIVITY IS STILL EXPECTED LATE THIS MORNING AND EARLY
AFTERNOON BEFORE NEW DIURNAL CONVECTION DEVELOPS. THIS NEW
CONVECTION WILL LIKELY HOLD OFF UNTIL PEAK HEATING AS THE NEW 12Z
SOUNDING HAS THE CONVECTIVE TEMPERATURE IN THE MID 70S.
THE QUESTION THEN BECOMES HOW FAR SOUTH WILL THE NEW CONVECTION GO
INTO THIS EVENING AND OVERNIGHT. THE OVERALL FORCING IS WEAK IN
SPITE OF A WEAK FRONT/BOUNDARY MOVING THROUGH. THE BETTER CHANCES
STILL APPEAR TO BE NORTH OF I-80. ..08..
&&
.SYNOPSIS...
ISSUED AT 305 AM CDT SUN AUG 11 2013
06Z SFC ANALYSIS HAS A WEAK LOW NEAR KICR WITH A STATIONARY FRONT
SOUTHEAST INTO WESTERN IOWA. A WEAK BOUNDARY RAN FROM SOUTHEAST
SOUTH DAKOTA INTO NORTHERN IOWA. DEW POINTS WERE IN THE 50S ACROSS
THE GREAT LAKES WITH 60S IN THE PLAINS AND 70S ACROSS THE DEEP SOUTH
AND OHIO VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
THE MCS AND LIFT TOOLS WHEN APPLIED TO TRENDS IN THE RAP AND OTHER
MODELS SUGGEST A MAJORITY OF THE PRECIPITATION WILL REMAIN NORTH OF
THE CWFA THROUGH MID DAY WITH SOME SHOWERS BRUSHING THE NORTHERN
CWFA IN THE HIGHWAY 20 CORRIDOR. RECENT TRENDS WITH THE RAP SUGGEST
PRECIPITATION MAY NOT BEGIN ENTERING THE NORTHERN CWFA UNTIL AROUND
SUNRISE.
PRECIPITATION SHOULD WANE DURING THE LATE MORNING AND EARLY
AFTERNOON BEFORE RE-DEVELOPING THIS AFTERNOON HOURS DURING MAX
HEATING. ANY PRECIPITATION IN THE HWY 20 CORRIDOR WILL EXPAND
SOUTHWARD TO HWY 30 AND EVENTUALLY TO I-80 BY LATE AFTERNOON.
TONIGHT...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE ACROSS
ROUGHLY THE NORTHERN HALF OF THE CWFA DURING THE EVENING BEFORE
SLOWLY SPREADING SOUTH AFTER MIDNIGHT. THE EXTREME SOUTHERN PART OF
THE CWFA CURRENTLY LOOKS TO BE DRY BOTH TODAY AND TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN AUG 11 2013
RAIN CHANCES LINGER EARLY IN THE WEEK THEN MAINLY DRY AND PLEASANT
REST OF THE PERIOD WITH NEAR TO BELOW NORMAL TEMPS.
MON-MON NGT... SURFACE AND 850 MB COLD FRONTS WILL GRADUALLY SLIDE
THROUGH THE AREA AS AN UPPER LEVEL TROUGH MOVES INTO THE GREAT
LAKES. 850 MB BOUNDARY IS SUGGESTED TO BE PRIMARY PCPN MECHANISM
DUE TO BETTER CONVERGENCE WITH SCATTERED ELEVATED SHOWERS AND
ISOLD STORMS MAINLY NORTH OF I-80 MON AM SLIDING SOUTHEAST IN THE
PM. CONVERGENCE ALONG SURFACE FRONT FAIRLY WEAK BUT IF SUFFICIENT
HEATING INTO THE MID 80S THEN CAPPING INVERSION SHOULD WEAKEN AND
JUST ENOUGH CONVERGENCE TO ALLOW SCATTERED STORMS TO DEVELOP FROM
MID PM TO EARLY EVE MAINLY JUST S/SE OF QUAD CITIES. ENVIRONMENT
LOOKS LIKE FAIRLY WEAK TO MARGINAL SHEAR (0-6KM BULK SHEAR 20-25 KTS)
AND MODERATE INSTABILITY (MUCAPES 1500-2000+ J/KG)... THUS MARGINAL
ISOLD PULSE TYPE STORMS SUGGESTED WITH SOME SMALL HAIL AND DOWNBURST
WINDS POSSIBLE. BANKING ON ANY PCPN MAINLY SCATTERED AND ENOUGH
BREAKS IN CLOUDS TO YIELD WIDESPREAD 80S FOR HIGHS WITH THE WARMEST
READINGS ACROSS THE SOUTHERN CWA. RAIN CHCS LINGER MON EVE ACROSS THE
SOUTH...THEN HIGH PRESSURE RIDGE BEGINS TO BUILD IN OVRNGT BRINGING IN
DRIER AIR. LOWS MON NGT COOLEST NORTH WHERE SOME 50S WHILE 60S ARE
LIKELY ELSEWHERE.
TUE-TUE NGT... UKMET IS AN OUTLIER HOLDING UP MID LEVEL BAROCLINIC
ZONE ACROSS SOUTHERN CWA AND GENERATING SOME ADDITIONAL PCPN ON TUE.
HAVE SIDED TOWARD CONSENSUS FCST WITH CONTINUED DRY AND COOL
ADVECTION WITH STRENGTHENING NORTHWEST FLOW ALOFT AND INCOMING SURFACE
RIDGE SHUNTING BAROCLINIC ZONE AND PCPN PROCESSES SOUTH/WEST OF THE
CWA. HIGHS TUE RANGING FROM SOME MID 70S NORTH TO LOWER 80S SOUTH WITH
PT-MOSUNNY SKIES. CONTINUED LOWERING OF DEWPTS MAINLY INTO THE 50S
COUPLED WITH N/NE WINDS 5-10 MPH SHOULD MAKE FOR A REAL NICE AND
VERY COMFORTABLE DAY FOR OUTDOOR ACTIVITIES. COOL CONDITIONS EXPECTED
TUE NGT WITH CLEARING SKIES AND LIGHT WINDS ALLOWING FOR WIDESPREAD
LOWS IN THE 50S.
WED-SAT...FLOW ALOFT WILL REMAIN NORTHWEST WITH LARGE EXPANSE OF HIGH
PRESSURE AT THE SURFACE SLOWLY SHIFTING FROM THE UPPER MIDWEST INTO
THE OH VLY. RESULT WILL BE A PROLONGED PERIOD OF FANTASTIC WX FEATURING
LOW HUMIDITY...LIGHT WINDS...MAINLY CLEAR SKIES AND SLIGHTLY BELOW
NORMAL TEMPS WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN
THE 50S TO AROUND 60F.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 649 AM CDT SUN AUG 11 2013
THE CURRENT NOCTURNAL CONVECTION IS MORE SHRA THAN TSRA. THERE
SHOULD BE A VCSH FOR KDBQ THROUGH MID MORNING BEFORE ALL ACTIVITY
DISSIPATES. SO...VFR WX STILL LOOKS ON TAP THROUGH 06Z/12. NEW
CONVECTION IS EXPECTED TO DEVELOP BY 21Z/11 THAT MAY RESULT IN
BRIEF MVFR CONDITIONS AT A TAF SITE. SHRA/TSRA WILL CONTINUE AFT
SUNSET WITH KDBQ POSSIBLY EXPERIENCING MVFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
317 AM CDT SUN AUG 11 2013
.SYNOPSIS...
ISSUED AT 305 AM CDT SUN AUG 11 2013
06Z SFC ANALYSIS HAS A WEAK LOW NEAR KICR WITH A STATIONARY FRONT
SOUTHEAST INTO WESTERN IOWA. A WEAK BOUNDARY RAN FROM SOUTHEAST
SOUTH DAKOTA INTO NORTHERN IOWA. DEW POINTS WERE IN THE 50S ACROSS
THE GREAT LAKES WITH 60S IN THE PLAINS AND 70S ACROSS THE DEEP SOUTH
AND OHIO VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
THE MCS AND LIFT TOOLS WHEN APPLIED TO TRENDS IN THE RAP AND OTHER
MODELS SUGGEST A MAJORITY OF THE PRECIPITATION WILL REMAIN NORTH OF
THE CWFA THROUGH MID DAY WITH SOME SHOWERS BRUSHING THE NORTHERN
CWFA IN THE HIGHWAY 20 CORRIDOR. RECENT TRENDS WITH THE RAP SUGGEST
PRECIPITATION MAY NOT BEGIN ENTERING THE NORTHERN CWFA UNTIL AROUND
SUNRISE.
PRECIPITATION SHOULD WANE DURING THE LATE MORNING AND EARLY
AFTERNOON BEFORE RE-DEVELOPING THIS AFTERNOON HOURS DURING MAX
HEATING. ANY PRECIPITATION IN THE HWY 20 CORRIDOR WILL EXPAND
SOUTHWARD TO HWY 30 AND EVENTUALLY TO I-80 BY LATE AFTERNOON.
TONIGHT...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE ACROSS
ROUGHLY THE NORTHERN HALF OF THE CWFA DURING THE EVENING BEFORE
SLOWLY SPREADING SOUTH AFTER MIDNIGHT. THE EXTREME SOUTHERN PART OF
THE CWFA CURRENTLY LOOKS TO BE DRY BOTH TODAY AND TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN AUG 11 2013
RAIN CHANCES LINGER EARLY IN THE WEEK THEN MAINLY DRY AND PLEASANT
REST OF THE PERIOD WITH NEAR TO BELOW NORMAL TEMPS.
MON-MON NGT... SURFACE AND 850 MB COLD FRONTS WILL GRADUALLY SLIDE
THROUGH THE AREA AS AN UPPER LEVEL TROUGH MOVES INTO THE GREAT
LAKES. 850 MB BOUNDARY IS SUGGESTED TO BE PRIMARY PCPN MECHANISM
DUE TO BETTER CONVERGENCE WITH SCATTERED ELEVATED SHOWERS AND
ISOLD STORMS MAINLY NORTH OF I-80 MON AM SLIDING SOUTHEAST IN THE
PM. CONVERGENCE ALONG SURFACE FRONT FAIRLY WEAK BUT IF SUFFICIENT
HEATING INTO THE MID 80S THEN CAPPING INVERSION SHOULD WEAKEN AND
JUST ENOUGH CONVERGENCE TO ALLOW SCATTERED STORMS TO DEVELOP FROM
MID PM TO EARLY EVE MAINLY JUST S/SE OF QUAD CITIES. ENVIRONMENT
LOOKS LIKE FAIRLY WEAK TO MARGINAL SHEAR (0-6KM BULK SHEAR 20-25 KTS)
AND MODERATE INSTABILITY (MUCAPES 1500-2000+ J/KG)... THUS MARGINAL
ISOLD PULSE TYPE STORMS SUGGESTED WITH SOME SMALL HAIL AND DOWNBURST
WINDS POSSIBLE. BANKING ON ANY PCPN MAINLY SCATTERED AND ENOUGH
BREAKS IN CLOUDS TO YIELD WIDESPREAD 80S FOR HIGHS WITH THE WARMEST
READINGS ACROSS THE SOUTHERN CWA. RAIN CHCS LINGER MON EVE ACROSS THE
SOUTH...THEN HIGH PRESSURE RIDGE BEGINS TO BUILD IN OVRNGT BRINGING IN
DRIER AIR. LOWS MON NGT COOLEST NORTH WHERE SOME 50S WHILE 60S ARE
LIKELY ELSEWHERE.
TUE-TUE NGT... UKMET IS AN OUTLIER HOLDING UP MID LEVEL BAROCLINIC
ZONE ACROSS SOUTHERN CWA AND GENERATING SOME ADDITIONAL PCPN ON TUE.
HAVE SIDED TOWARD CONSENSUS FCST WITH CONTINUED DRY AND COOL
ADVECTION WITH STRENGTHENING NORTHWEST FLOW ALOFT AND INCOMING SURFACE
RIDGE SHUNTING BAROCLINIC ZONE AND PCPN PROCESSES SOUTH/WEST OF THE
CWA. HIGHS TUE RANGING FROM SOME MID 70S NORTH TO LOWER 80S SOUTH WITH
PT-MOSUNNY SKIES. CONTINUED LOWERING OF DEWPTS MAINLY INTO THE 50S
COUPLED WITH N/NE WINDS 5-10 MPH SHOULD MAKE FOR A REAL NICE AND
VERY COMFORTABLE DAY FOR OUTDOOR ACTIVITIES. COOL CONDITIONS EXPECTED
TUE NGT WITH CLEARING SKIES AND LIGHT WINDS ALLOWING FOR WIDESPREAD
LOWS IN THE 50S.
WED-SAT...FLOW ALOFT WILL REMAIN NORTHWEST WITH LARGE EXPANSE OF HIGH
PRESSURE AT THE SURFACE SLOWLY SHIFTING FROM THE UPPER MIDWEST INTO
THE OH VLY. RESULT WILL BE A PROLONGED PERIOD OF FANTASTIC WX FEATURING
LOW HUMIDITY...LIGHT WINDS...MAINLY CLEAR SKIES AND SLIGHTLY BELOW
NORMAL TEMPS WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN
THE 50S TO AROUND 60F.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
VFR WX IS EXPECTED THROUGH 06Z/12. THE POSSIBILITY DOES EXIST THAT
KDBQ MAY SEE VCSH OR EVEN VCTS IN THE 12Z/11 TO 18Z/11 TIME FRAME.
AFT 18Z/11 DIURNAL CONVECTION WILL DEVELOP THAT MAY AFFECT A TAF
SITE WITH A BRIEF PERIOD OF MVFR CONDITIONS. AFT 06Z/12 THE
POSSIBILITY DOES EXIST FOR POCKETS OF MVFR VSBYS DEVELOPING ACROSS
EASTERN IOWA AND NORTHERN ILLINOIS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS PADUCAH KY
736 PM CDT Mon Aug 12 2013
.UPDATE...
Updated aviation discussion only.
&&
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 1250 PM CDT MON AUG 12 2013
It looks like the blended model approach is too slow. It lingers
pops well after fropa into/thru Tuesday. We went with the HRRR and
Nam`s more meso type solutions, which had higher resolution and
initiated well. It has higher pops but departs them more quickly
with fropa and with the aforementioned finer resolution. It models
the initial environment well, so we at least are hoping for a nice
0-6 hr init with a transition toward the Nam in the overall pop
modeling thru Tuesday. Alot will be told here with how the
remainder of the pm/into the early evening goes. Should see fairly
active/high concentration convection to continue breaking out in
moist/unstable air ahead of incoming front/energy this pm-
evening...to sweep southward with time/with perhaps additional
development along main front as well as outflow boundaries thru
the overnight hours. Meso models take the front thru tonight and
start to usher in the drier air at the lower levels late tonight-
early tmrw, which should preclude pop mention. We`ll watch closely
and also see about collab as to whether to remove pop altogether or
leave lingering Tuesday pop. Certainly by Tue evening-overnight all
models are in agreement that the drier dew points are working thru
the column and we poise for the nice pleasant cooler/drier air to
take root from mid week on.
.LONG TERM /Wednesday through Monday/...
ISSUED AT 215 PM CDT MON AUG 12 2013
Unusually high amplitude flow pattern for the middle of August will
continue...with a large ridge in the west and a deep trough in the
Mississippi and Ohio Valley regions. The trough is forecast to
weaken late in the period /Monday/...which will result in some
semblance of a typical August pattern.
As far as the daily details...
An unseasonably strong /1023 mb/ surface high will progress slowly
east across the Great Lakes and upper Midwest Wednesday through
Thursday. This high will funnel a cool and dry air mass
southward...with 850 mb temps ranging from 10 to 12 for much of the
period. These 850 mb temps support highs only in the upper 70s with
full sun. Overnight lows will be in the lower to mid 50s. Generally
followed the cooler NAM mos for low temps...though the difference
between NAM and GFS mos is negligible in some places. It should be
noted that 850 mb temp anomalies Wed/Thu will be 2 to 3 standard
deviations below normal. The air mass will also be very dry. Model
soundings suggest nothing more than a few pancake cumulus clouds
each afternoon.
On Friday and Friday night...an inverted surface trough will
retrograde westward across the Tennessee Valley as a 500 mb
shortwave digs southeast into the Mississippi Valley. It will take a
while for the atmosphere to moisten up...so only the far southeast
counties /KHOP area/ nearest the surface trough are at risk of any
precip.
Saturday through Sunday...the upper trough will be nearly overhead.
Some guidance indicates the trough will close off into an upper low
over our region. At low levels...the inverted trough will take up
residence near or just south of our region. Dew point pooling along
the surface trough will bring dew points up through the 60s. Precip
water values are forecast to climb steadily to between 1.5 and 2
inches by Sunday /GFS model/. The models are considerably more
unstable than they were yesterday...so will add mention of thunder
for the weekend. Pops will be in the chance category in most areas
for Sunday. Most of the precip should be diurnally driven
convection.
On Monday...the upper trough is forecast to weaken and/or lift
northeast. The surface trough will dissipate...leaving only a
weakly cyclonic east to southeast flow. Precip chances will begin to
diminish from the west. Temps and humidity will gradually approach
climo.
&&
.AVIATION...
ISSUED AT 736 PM CDT MON AUG 12 2013
Deep convection was on a rapid move ewd this evening, now east of
the four TAF sites. Behind this activity, winds across the area will
be rather light and generally from the west or sw, until a cold
front passes through the area late in the night, turning winds to
the nw. There is a small chance of pcpn ahead of the front, but the
probability of occurrence was too low to include in TAFs. With the
possible exception of high MVFR cigs in the ern terminals for a few
hours along and behind the front, and a few low clouds possible this
evening, VFR conditions are expected. Drier air arriving behind the
front should greatly limit the possibility of fog near sunrise.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
Short term...DH
Long term...MY
Aviation...DB
AREA FORECAST DISCUSSION
NWS JACKSON KY
134 PM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 107 PM EDT SUN AUG 11 2013
HAD TO ISSUE ANOTHER QUICK UPDATE TO THE FORECAST. THE INHERITED
FORECAST HAD THE HIGHEST PRECIPITATION PROBABILITIES ALONG AND JUST
NORTH AND WEST OF THE TENNESSEE AND VIRGINIA BORDERS RESPECTIVELY.
HOWEVER...SHOWERS AND STORMS IN THAT AREA HAVE DISSIPATED ALMOST
COMPLETELY OVER THE PAST COUPLE OF HOURS. WITH SCATTERED SHOWERS AND
STORMS NOW FIRING IN VICINITY OF THE FRONTAL BOUNDARY WELL NORTH OF
THE TENNESSEE LINE...THE FORECAST POPS...SKY COVER...AND QPF HAD TO
ALL BE MODIFIED TO REFLECT THIS NEW TRENDS. THEREFORE...PRECIPITATION
CHANCES FOR AREAS NORTH OF THE HAL ROGERS PARKWAY WERE INCREASED TO
50 PERCENT FOR THE REST OF THE DAY...WHILE THE POPS SOUTH OF THERE
WERE LOWERED DRAMATICALLY AND SLOWLY RAMPED UP TOWARD LATE
AFTERNOON...AS THE FRONT...AND THE WAVE OF LOW PRESSURE THAT HAS
FORMED ALONG IT...MOVE OFF TO THE EAST. THE UPDATED ZONES HAVE
ALREADY BEEN SENT.
UPDATE ISSUED AT 1047 AM EDT SUN AUG 11 2013
MADE A FEW UPDATES TO THE INHERITED FORECAST. REMOVED THE PRE-FIRST
PERIOD THAT WAS INCLUDED WITH THE 4 AM FORECAST PACKAGE...AND REMOVED
MENTION OF EARLY MORNING FOG. THE HIGHER PRECIPITATION CHANCES FROM
EARLIER THIS MORNING WERE ALSO REMOVED FROM THE TODAY PERIOD...AS THE
AREA IS CURRENTLY EXPERIENCING A LULL IN SHOWERS AND STORMS.
HOWEVER...WITH A SLUGGISH FRONTAL BOUNDARY MEANDERING ABOUT ACROSS
THE AREA...ANTICIPATE THAT SHOWERS AND STORMS WILL AGAIN INCREASE IN
COVERAGE AS THE DAY WEARS ON...PARTICULARLY ALONG AND SOUTH OF THE
HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDOR. LOCALLY HEAVY RAINFALL
WILL REMAIN A POSSIBILITY THROUGHOUT THE DAY WHERE MORE WIDESPREAD
SHOWERS AND STORMS OCCUR.
UPDATE ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO OUT OF SORTS IN THIS PATTERN TO
BITE ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE
RUN. DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A
THREAT FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN AUG 11 2013
A VERY CHALLENGING TAF FORECAST YET AGAIN TODAY. AN WEST TO EAST
ORIENTED LINE OF SHOWERS AND THUNDERSTORMS HAS FORMED AND IS MOVING
ALONG THE MOUNTAIN PARKWAY. THESE SHOWERS AND STORMS ARE EXPECTED TO
INCREASE IN COVERAGE AS THE AFTERNOON WEARS ON AND EXPAND SOUTH AS
A FRONTAL BOUNDARY AND A WAVE OF LOW PRESSURE MOVE EAST ACROSS THE
AREA. JKL WILL SEE THE FIRST ROUND OF SHOWERS AND STORMS TODAY AND
COULD EXPERIENCE PERIODS OF MVFR CONDITIONS WHILE THE RAIN IS
FALLING. LOZ AND SME SHOULD BE OFF THE HOOK UNTIL 20 OR 21Z...AS THE
AFOREMENTIONED WEATHER SYSTEMS MAKES ITS WAY EASTWARD. MVFR
CONDITIONS WILL ALSO BE EXPECTED AT LOZ AND SME WHEN SHOWERS AND
STORMS EVENTUALLY AFFECT THOSE TAF SITES DIRECTLY. LATER
TONIGHT...AFTER 5Z OR SO...FOG IS ON TAP FOR THE TAF SITES...AS
COOLER AIR SETTLES IN BEHIND THE FRONT. CONSIDERING THE AMOUNT OF
RAIN THAT HAS FALLEN ACROSS THE ENTIRE AREA THE PAST SEVERAL
DAYS...AND WITH PARTLY CLOUDY SKIES AND LIGHT WINDS EXPECTED...FOG
WILL BE A GOOD BET LATER TONIGHT INTO EARLY TOMORROW MORNING. IN
GENERAL...IFR CONDITIONS ARE EXPECTED WHEN THE FOG IS AT ITS WORST
AND JKL AND LOZ...BUT THERE COULD BE BRIEF PERIODS OF LIFR CONDITIONS
TOWARDS DAWN TOMORROW...AS THE RAIN OF THE PAST SEVERAL DAYS HAS
SATURATED THE GROUND AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
107 PM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 107 PM EDT SUN AUG 11 2013
HAD TO ISSUE ANOTHER QUICK UPDATE TO THE FORECAST. THE INHERITED
FORECAST HAD THE HIGHEST PRECIPITATION PROBABILITIES ALONG AND JUST
NORTH AND WEST OF THE TENNESSEE AND VIRGINIA BORDERS RESPECTIVELY.
HOWEVER...SHOWERS AND STORMS IN THAT AREA HAVE DISSIPATED ALMOST
COMPLETELY OVER THE PAST COUPLE OF HOURS. WITH SCATTERED SHOWERS AND
STORMS NOW FIRING IN VICINITY OF THE FRONTAL BOUNDARY WELL NORTH OF
THE TENNESSEE LINE...THE FORECAST POPS...SKY COVER...AND QPF HAD TO
ALL BE MODIFIED TO REFLECT THIS NEW TRENDS. THEREFORE...PRECIPITATION
CHANCES FOR AREAS NORTH OF THE HAL ROGERS PARKWAY WERE INCREASED TO
50 PERCENT FOR THE REST OF THE DAY...WHILE THE POPS SOUTH OF THERE
WERE LOWERED DRAMATICALLY AND SLOWLY RAMPED UP TOWARD LATE
AFTERNOON...AS THE FRONT...AND THE WAVE OF LOW PRESSURE THAT HAS
FORMED ALONG IT...MOVE OFF TO THE EAST. THE UPDATED ZONES HAVE
ALREADY BEEN SENT.
UPDATE ISSUED AT 1047 AM EDT SUN AUG 11 2013
MADE A FEW UPDATES TO THE INHERITED FORECAST. REMOVED THE PRE-FIRST
PERIOD THAT WAS INCLUDED WITH THE 4 AM FORECAST PACKAGE...AND REMOVED
MENTION OF EARLY MORNING FOG. THE HIGHER PRECIPITATION CHANCES FROM
EARLIER THIS MORNING WERE ALSO REMOVED FROM THE TODAY PERIOD...AS THE
AREA IS CURRENTLY EXPERIENCING A LULL IN SHOWERS AND STORMS.
HOWEVER...WITH A SLUGGISH FRONTAL BOUNDARY MEANDERING ABOUT ACROSS
THE AREA...ANTICIPATE THAT SHOWERS AND STORMS WILL AGAIN INCREASE IN
COVERAGE AS THE DAY WEARS ON...PARTICULARLY ALONG AND SOUTH OF THE
HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDOR. LOCALLY HEAVY RAINFALL
WILL REMAIN A POSSIBILITY THROUGHOUT THE DAY WHERE MORE WIDESPREAD
SHOWERS AND STORMS OCCUR.
UPDATE ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO OUT OF SORTS IN THIS PATTERN TO
BITE ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE
RUN. DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A
THREAT FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN AUG 11 2013
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH SOUTHEAST KENTUCKY THIS MORNING. THE LOWER CIGS AND VSBY
WILL CONTINUE TO BE HIT AND MISS THROUGH THE MORNING. AN IMPROVEMENT
TO VFR SHOULD TAKE PLACE BY LATE MORNING. SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY POINT THROUGH THE
DAY. TONIGHT...DO EXPECT SOME LOWER VIS AND CIGS DUE TO FOG AS THE
FROM FINALLY SINKS SOUTH OF THE TAF SITES. WINDS WILL BE LIGHT AND
VARIABLE DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
1048 AM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 1047 AM EDT SUN AUG 11 2013
MADE A FEW UPDATES TO THE INHERITED FORECAST. REMOVED THE PRE-FIRST
PERIOD THAT WAS INCLUDED WITH THE 4 AM FORECAST PACKAGE...AND REMOVED
MENTION OF EARLY MORNING FOG. THE HIGHER PRECIPITATION CHANCES FROM
EARLIER THIS MORNING WERE ALSO REMOVED FROM THE TODAY PERIOD...AS THE
AREA IS CURRENTLY EXPERIENCING A LULL IN SHOWERS AND STORMS.
HOWEVER...WITH A SLUGGISH FRONTAL BOUNDARY MEANDERING ABOUT ACROSS
THE AREA...ANTICIPATE THAT SHOWERS AND STORMS WILL AGAIN INCREASE IN
COVERAGE AS THE DAY WEARS ON...PARTICULARLY ALONG AND SOUTH OF THE
HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDOR. LOCALLY HEAVY RAINFALL
WILL REMAIN A POSSIBILITY THROUGHOUT THE DAY WHERE MORE WIDESPREAD
SHOWERS AND STORMS OCCUR.
UPDATE ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO OUT OF SORTS IN THIS PATTERN TO
BITE ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE
RUN. DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A
THREAT FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN AUG 11 2013
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH SOUTHEAST KENTUCKY THIS MORNING. THE LOWER CIGS AND VSBY
WILL CONTINUE TO BE HIT AND MISS THROUGH THE MORNING. AN IMPROVEMENT
TO VFR SHOULD TAKE PLACE BY LATE MORNING. SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY POINT THROUGH THE
DAY. TONIGHT...DO EXPECT SOME LOWER VIS AND CIGS DUE TO FOG AS THE
FROM FINALLY SINKS SOUTH OF THE TAF SITES. WINDS WILL BE LIGHT AND
VARIABLE DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
730 AM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO SQUIRRELLY IN THIS PATTERN TO BITE
ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE RUN.
DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A THREAT
FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN AUG 11 2013
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH SOUTHEAST KENTUCKY THIS MORNING. THE LOWER CIGS AND VSBY
WILL CONTINUE TO BE HIT AND MISS THROUGH THE MORNING. AN IMPROVEMENT
TO VFR SHOULD TAKE PLACE BY LATE MORNING. SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY POINT THROUGH THE
DAY. TONIGHT...DO EXPECT SOME LOWER VIS AND CIGS DUE TO FOG AS THE
FROM FINALLY SINKS SOUTH OF THE TAF SITES. WINDS WILL BE LIGHT AND
VARIABLE DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
325 AM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO SQUIRRELLY IN THIS PATTERN TO BITE
ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE RUN.
DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A THREAT
FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 210 AM EDT SUN AUG 11 2013
THE LAST OF THE SHOWERS AND FORMER THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH FAR EAST KENTUCKY EARLY THIS MORNING. THE LOWER CIGS AND
VSBY WILL BE HIT AND MISS THROUGH THE NIGHT AND WILL PROBABLY NOT
BLANKET THE ENTIRE AREA. AN IMPROVEMENT TO VFR SHOULD TAKE PLACE BY
LATE MORNING ON SUNDAY. SHOWERS WILL BE POSSIBLE AT JUST ABOUT ANY
POINT THROUGH THE DAY ON SUNDAY. WINDS WILL BE LIGHT AND VARIABLE
DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 PM EDT MON AUG 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT MON AUG 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER
JAMES BAY WITH A WELL-DEFINED SHORTWAVE TROUGH/PV ANOMALY
TO THE WEST NEAR CYPL. A WEAK 850-700 MB TROUGH SUPPORTED SOME ISOLD
SHOWERS THROUGH N CNTRL UPPER MI AND ERN LAKE SUPERIOR. AT THE
SFC...A TROUGH EXTENDED THROUGH WRN LAKE SUPERIOR AHEAD OF A COLD
FRONT DROPPING THROUGH NRN ONTARIO TO NEAR CYGQ.
TODAY...EXPECT THAT THE NW ONTARIO SHRTWV BRUSHING UPPER MI DURING
INCREASED DAYTIME HEATING AND LAKE BREEZE BOUNDARY DEVELOPMENT...
WILL BE ENOUGH TO TRIGGER ADDITIONAL ISOLD/SCT SHOWERS OVER MAINLY
THE CNTRL AND ERN CWA. WITH MLCAPE VALUES ONLY FCST INTO THE 100-300
J/KG RANGE...AND THE STRONGER 700-300 MB QVECTOR CONV WITH THE SHRTWV
AND STEEPER MID LEVEL LAPSE RATES REMAINING TO THE NORTH...TSRA WERE
NOT MENTIONED. CLOUDS AND INCREASING NRLY FLOW WILL KEEP TEMPS BELOW
NORMAL WITH HIGHS IN THE UPPER 60S NORTH AND LOWER 70S SOUTH.
TONIGHT...ANY REMAINING SHOWERS ARE EXPECTED TO DIMINISH QUICKLY AS
SUBSIDENCE INCREASES IN THE WAKE OF THE SHRTWV AND DAYTIME HEATING
SUBSIDES. WITH CLEARING SKIES AND PWAT VALUES FALLING TO AROUND 0.50
INCH(50 PCT OR NORMAL)...TEMPS OVER THE INTERIOR WEST ARE EXPECTED
TO FALL INTO THE LOWER 40S...CLOSER TO THE LOWER END OF GUIDANCE.
LINGERING LOW LEVEL NW FLOW OVER THE EAST SHOULD STILL BE STRONG
ENOUGH TO KEEP TEMPS FROM DROPPING OFF AS MUCH WITH MINS ONLY IN THE
UPPER 40S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM EDT MON AUG 12 2013
COOL AND DRY WEATHER IS EXPECTED THROUGH THE WORK WEEK AS HIGH
PRESSURE DOMINATES THE PATTERN. A SERIES OF WEAK SHORTWAVES ROTATING
AROUND THE BACKSIDE OF AN EASTERN CANADIAN TROUGH COULD BRING SOME
INCREASED CLOUDINESS AT TIMES...BUT LITTLE IF ANY PRECIP IS
EXPECTED.
TUESDAY AND TUESDAY NIGHT...DEEP TROUGHING CENTERED OVER WESTERN
QUEBEC IS CURRENTLY COMPRISED OF A HALF DOZEN OR SO EMBEDDED
SHORTWAVES THAT ARE DEPICTED IN WV IMAGERY. ONE WAVE OVER NORTHERN
HUDSON BAY IS PROGGED TO BE MOVING SE ACROSS THE CWA AT THE START OF
THE PERIOD. THIS FEATURE HAS COMPLICATED FORECASTS FOR TUESDAY AS IT
WAS NOT PICKED UP WELL BY ANY MODEL UNTIL WITHIN THE PAST 36 HRS.
THE WAVE WILL OUTRUN PEAK HEATING...SO WITH DEPLETED MOISTURE BEHIND
TODAYS SYSTEM...CAPPING AROUND H7 BEHIND THE WAVE...AND SFC DEW
POINTS IN THE 40S...WOULD EXPECT TO SEE ONLY A DIURNAL CUMULUS FIELD
WITH POSSIBLY SOME SPRINKLES. WILL OPT TO KEEP PRECIP MENTION OUT OF
THE FORECAST ATTM...BUT WILL BOOST UP AFTERNOON CLOUD COVER A BIT.
QUITE A COOL NIGHT IS IN THE MAKING TUESDAY NIGHT AS THE AXIS OF
HIGH PRESSURE BUILDING INTO THE REGION SETTLES OVER THE WESTERN CWA.
PWAT AROUND 0.5 INCHES AND LIGHT WINDS WILL PROMOTE EXCELLENT
RADIATIONAL COOLING ACROSS THE AREA. CONTINUED TO EMPLOY
GUIDANCE...CHIEFLY BIAS CORRECTED MOS...THAT HAS PERFORMED
EXCEPTIONALLY WELL WITH SIMILAR NIGHTS OVER THE PAST SEVERAL WEEKS.
CURRENT FORECAST IS FOR UPPER 30S INTERIOR WEST TO LOW 40S ELSEWHERE
INLAND TO AROUND 50 VERY NEAR THE GREAT LAKES SHORES. ANOTHER WEAK
SHORTWAVE WILL TRACK SE ACROSS THE AREA LATE IN THE NIGHT...BUT WITH
LITTLE MOISTURE...DO NOT EVEN EXPECT MID CLOUDS.
WEDNESDAY THROUGH THURSDAY...ANOTHER WEAK WAVE WILL PUSH SE ACROSS
THE CWA WEDNESDAY MORNING...AND YET ANOTHER ONE THURSDAY MORNING.
BOTH LOOK RATHER BENIGN ATTM WITH MOISTURE STILL QUITE LOW. BOTH
DAYS SHOULD SEE SHALLOW CUMULUS DEVELOPMENT INLAND WITH SUBSTANTIAL
CAPPING AT H7. DEPARTING SFC HIGH PRESSURE WILL BRING A COUPLE MORE
COOL NIGHTS BEFORE FRIDAY. HAVE CONTINUED TO USE COLDER GUIDANCE FOR
THESE NIGHTS AS PWAT WILL STILL BE BELOW 0.7 INCHES.
FRIDAY THROUGH SUNDAY...A WARMING TREND IS IN STORE BY THE END OF
THE WEEK...WITH WIDESPREAD 70S AND A FEW 80S TIPPING THE SCALE BACK
TO ABOVE AVERAGE TEMPS. MODEL GUIDANCE IS IN DECENT AGREEMENT THAT A
TROUGH FROM WESTERN CANADA WILL BEGIN ERODING RIDGING OVER THE
NORTHERN PLAINS BY LATE THURSDAY. HOWEVER...THERE IS SOME
DISAGREEMENT AS TO THE MAGNITUDE AND DURATION OF THIS PROCESS. THE
ECMWF IS MUCH MORE CONSERVATIVE THAN THE GFS IN BRINGING THE TROUGH
INTO THE UPPER MS VALLEY...HOLDING OFF UNTIL LATE NEXT WEEKEND. THE
GFS BRINGS PRECIP INTO THE WESTERN CWA AS EARLY AS FRIDAY NIGHT.
BOTH HAVE BEEN QUITE CONSISTENT WITH THEIR RESPECTIVE FORECASTS...SO
CANNOT RULE OUT EITHER. EXPERIENCE TENDS TO LEAN TOWARD THE SLOWER
PROGRESSION OF THE ECMWF IN BREAKING DOWN A SUMMERTIME RIDGE.
HOWEVER...GIVEN UNCERTAINTY...WILL MAINTAIN CONSENSUS FORECAST OF
SLIGHT CHANCE OF SHOWERS AND STORMS BEGINNING LATE SATURDAY INTO
SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 133 PM EDT MON AUG 12 2013
BY THE START OF THE TAF...THINK LOWER CLOUDS AND VCSH NOW AT KCMX
WILL BE GONE...BUT THEY MAY LINGER A BIT LONGER THAN EXPECTED. IWD
SHOULD BE DONE WITH PRECIP FOR THE REST OF THE TAF PERIOD...BUT MAY
SEE SOME SCT LOWER CLOUDS COME IN OVER THE NEXT FEW HOURS. SAW WILL
SEE THE MOST ACTIVE WEATHER FOR THE NEXT FEW HOURS AS SHOWERS AND
THUNDERSTORMS MOVE ACROSS THE AREA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT MON AUG 12 2013
AFTER A TROUGH MOVES THROUGH LAKE SUPERIOR EARLY...A WEAK COLD FRONT
WILL MOVE THROUGH LAKE SUPERIOR TODAY. HOWEVER...WINDS ARE EXPECTED
TO REMAIN LESS THAN 20 KNOTS. HIGH PRESSURE WILL RESUME CONTROL OF
THE WRN GREAT LAKES TUESDAY THROUGH THE END OF THE WEEK TO KEEP
WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 AM EDT MON AUG 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 503 AM EDT MON AUG 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER
JAMES BAY WITH A WELL-DEFINED SHORTWAVE TROUGH/PV ANOMALY
TO THE WEST NEAR CYPL. A WEAK 850-700 MB TROUGH SUPPORTED SOME ISOLD
SHOWERS THROUGH N CNTRL UPPER MI AND ERN LAKE SUPERIOR. AT THE
SFC...A TROUGH EXTENDED THROUGH WRN LAKE SUPERIOR AHEAD OF A COLD
FRONT DROPPING THROUGH NRN ONTARIO TO NEAR CYGQ.
TODAY...EXPECT THAT THE NW ONTARIO SHRTWV BRUSHING UPPER MI DURING
INCREASED DAYTIME HEATING AND LAKE BREEZE BOUNDARY DEVELOPMENT...
WILL BE ENOUGH TO TRIGGER ADDITIONAL ISOLD/SCT SHOWERS OVER MAINLY
THE CNTRL AND ERN CWA. WITH MLCAPE VALUES ONLY FCST INTO THE 100-300
J/KG RANGE...AND THE STRONGER 700-300 MB QVECTOR CONV WITH THE SHRTWV
AND STEEPER MID LEVEL LAPSE RATES REMAINING TO THE NORTH...TSRA WERE
NOT MENTIONED. CLOUDS AND INCREASING NRLY FLOW WILL KEEP TEMPS BELOW
NORMAL WITH HIGHS IN THE UPPER 60S NORTH AND LOWER 70S SOUTH.
TONIGHT...ANY REMAINING SHOWERS ARE EXPECTED TO DIMINISH QUICKLY AS
SUBSIDENCE INCREASES IN THE WAKE OF THE SHRTWV AND DAYTIME HEATING
SUBSIDES. WITH CLEARING SKIES AND PWAT VALUES FALLING TO AROUND 0.50
INCH(50 PCT OR NORMAL)...TEMPS OVER THE INTERIOR WEST ARE EXPECTED
TO FALL INTO THE LOWER 40S...CLOSER TO THE LOWER END OF GUIDANCE.
LINGERING LOW LEVEL NW FLOW OVER THE EAST SHOULD STILL BE STRONG
ENOUGH TO KEEP TEMPS FROM DROPPING OFF AS MUCH WITH MINS ONLY IN THE
UPPER 40S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM EDT MON AUG 12 2013
COOL AND DRY WEATHER IS EXPECTED THROUGH THE WORK WEEK AS HIGH
PRESSURE DOMINATES THE PATTERN. A SERIES OF WEAK SHORTWAVES ROTATING
AROUND THE BACKSIDE OF AN EASTERN CANADIAN TROUGH COULD BRING SOME
INCREASED CLOUDINESS AT TIMES...BUT LITTLE IF ANY PRECIP IS
EXPECTED.
TUESDAY AND TUESDAY NIGHT...DEEP TROUGHING CENTERED OVER WESTERN
QUEBEC IS CURRENTLY COMPRISED OF A HALF DOZEN OR SO EMBEDDED
SHORTWAVES THAT ARE DEPICTED IN WV IMAGERY. ONE WAVE OVER NORTHERN
HUDSON BAY IS PROGGED TO BE MOVING SE ACROSS THE CWA AT THE START OF
THE PERIOD. THIS FEATURE HAS COMPLICATED FORECASTS FOR TUESDAY AS IT
WAS NOT PICKED UP WELL BY ANY MODEL UNTIL WITHIN THE PAST 36 HRS.
THE WAVE WILL OUTRUN PEAK HEATING...SO WITH DEPLETED MOISTURE BEHIND
TODAYS SYSTEM...CAPPING AROUND H7 BEHIND THE WAVE...AND SFC DEW
POINTS IN THE 40S...WOULD EXPECT TO SEE ONLY A DIURNAL CUMULUS FIELD
WITH POSSIBLY SOME SPRINKLES. WILL OPT TO KEEP PRECIP MENTION OUT OF
THE FORECAST ATTM...BUT WILL BOOST UP AFTERNOON CLOUD COVER A BIT.
QUITE A COOL NIGHT IS IN THE MAKING TUESDAY NIGHT AS THE AXIS OF
HIGH PRESSURE BUILDING INTO THE REGION SETTLES OVER THE WESTERN CWA.
PWAT AROUND 0.5 INCHES AND LIGHT WINDS WILL PROMOTE EXCELLENT
RADIATIONAL COOLING ACROSS THE AREA. CONTINUED TO EMPLOY
GUIDANCE...CHIEFLY BIAS CORRECTED MOS...THAT HAS PERFORMED
EXCEPTIONALLY WELL WITH SIMILAR NIGHTS OVER THE PAST SEVERAL WEEKS.
CURRENT FORECAST IS FOR UPPER 30S INTERIOR WEST TO LOW 40S ELSEWHERE
INLAND TO AROUND 50 VERY NEAR THE GREAT LAKES SHORES. ANOTHER WEAK
SHORTWAVE WILL TRACK SE ACROSS THE AREA LATE IN THE NIGHT...BUT WITH
LITTLE MOISTURE...DO NOT EVEN EXPECT MID CLOUDS.
WEDNESDAY THROUGH THURSDAY...ANOTHER WEAK WAVE WILL PUSH SE ACROSS
THE CWA WEDNESDAY MORNING...AND YET ANOTHER ONE THURSDAY MORNING.
BOTH LOOK RATHER BENIGN ATTM WITH MOISTURE STILL QUITE LOW. BOTH
DAYS SHOULD SEE SHALLOW CUMULUS DEVELOPMENT INLAND WITH SUBSTANTIAL
CAPPING AT H7. DEPARTING SFC HIGH PRESSURE WILL BRING A COUPLE MORE
COOL NIGHTS BEFORE FRIDAY. HAVE CONTINUED TO USE COLDER GUIDANCE FOR
THESE NIGHTS AS PWAT WILL STILL BE BELOW 0.7 INCHES.
FRIDAY THROUGH SUNDAY...A WARMING TREND IS IN STORE BY THE END OF
THE WEEK...WITH WIDESPREAD 70S AND A FEW 80S TIPPING THE SCALE BACK
TO ABOVE AVERAGE TEMPS. MODEL GUIDANCE IS IN DECENT AGREEMENT THAT A
TROUGH FROM WESTERN CANADA WILL BEGIN ERODING RIDGING OVER THE
NORTHERN PLAINS BY LATE THURSDAY. HOWEVER...THERE IS SOME
DISAGREEMENT AS TO THE MAGNITUDE AND DURATION OF THIS PROCESS. THE
ECMWF IS MUCH MORE CONSERVATIVE THAN THE GFS IN BRINGING THE TROUGH
INTO THE UPPER MS VALLEY...HOLDING OFF UNTIL LATE NEXT WEEKEND. THE
GFS BRINGS PRECIP INTO THE WESTERN CWA AS EARLY AS FRIDAY NIGHT.
BOTH HAVE BEEN QUITE CONSISTENT WITH THEIR RESPECTIVE FORECASTS...SO
CANNOT RULE OUT EITHER. EXPERIENCE TENDS TO LEAN TOWARD THE SLOWER
PROGRESSION OF THE ECMWF IN BREAKING DOWN A SUMMERTIME RIDGE.
HOWEVER...GIVEN UNCERTAINTY...WILL MAINTAIN CONSENSUS FORECAST OF
SLIGHT CHANCE OF SHOWERS AND STORMS BEGINNING LATE SATURDAY INTO
SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 737 AM EDT MON AUG 12 2013
THE APPROACH OF ANOTHER SHORTWAVE LATER THIS MORNING INTO THE AFTERNOON
ACROSS LAKE SUPERIOR WILL BRING A THREAT OF MORE -SHRA TO MAINLY CMX
AND SAW...BUT CONFIDENCE REMAINS TOO LOW TO INCLUDE MORE THAN VCSH IN
THE TAF. ANY SHRA WILL END LATER THIS AFTERNOON WITH
DRYING/SUBSIDENCE IN THE WAKE OF THE DEPARTING SHORTWAVE. SINCE THE
LOW LEVELS WILL REMAIN DRY THROUGH THE FCST PERIOD...EXPECT VFR
CONDITIONS AT ALL 3 TAF SITES EVEN IF THERE IS A -SHRA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 503 AM EDT MON AUG 12 2013
AFTER A TROUGH MOVES THROUGH LAKE SUPERIOR EARLY...A WEAK COLD FRONT
WILL MOVE THROUGH LAKE SUPERIOR TODAY. HOWEVER...WINDS ARE EXPECTED
TO REMAIN LESS THAN 20 KNOTS. HIGH PRESSURE WILL RESUME CONTROL OF
THE WRN GREAT LAKES TUESDAY THROUGH THE END OF THE WEEK TO KEEP
WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 PM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EDT SUN AUG 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WRLY FLOW THROUGH THE NRN
GREAT LAKES ON THE SRN FLANK OF A MID/UPPER LEVEL TROUGH EXTENDING
FROM HUDSON BAY TO NEW FOUNDLAND. A WELL-DEFINED UPSTREAM SHORTWAVE
TROUGH LOCATED NEAR THE NW CORNER OF MN SUPPORTED A BAND OF LIGHT
SHOWERS OVER N CNTRL MN. THE HEAVIER SHRA/TSRA REMAINED WELL TO THE
SOUTH FROM SE SD AND SW MN INTO NW IA ALONG THE 850 MB FRONT. AT THE
SFC...A WEAK TROUGH AHEAD OF THE MID LEVEL SHRTWV EXTENDED FROM NEAR
CYQT NRN MN. IR LOOP SHOWED MAINLY CLEAR SKIES OVER UPPER MI WITH
MID CLOUDS APPROACHING FROM NE MN.
TODAY...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE TIMING OF
THE SHRTWV ACROSS THE AREA BRINGING THIS FEATURE INTO CNTRL UPPER MI
AROUND 18Z AND QUICKLY TO LAKE HURON BY 00Z. THE COMBINATION OF THE
WEAK 700-300 MB QVECTOR CONV WITH THE SHRTWV AND LOW LEVEL CONV
ALONG THE TROUGH AND LAKE BREEZE BOUNDARIES SHOULD BE ENOUGH TO
SUPPORT AT LEAST SUPPORT ISOLD/SCT PCPN. MLCAPE VALUES TO AROUND 400
J/KG...PER NAM...WILL BE MARGINAL FOR TSRA BUT WITH THE ARRIVAL OF
THE SHRTWV DURING PEAK HEATING ISOLD TSRA WILL ALSO BE POSSIBLE.
TONIGHT...ANY SHRA/TSRA THAT DEVELOP DURING THE AFTERNOON WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING AND THE DEPARTURE OF THE
SHRTWV. A SLIGHT CHANCE FOR SHOWERS WAS MENTIONED AS ANOTHER WEAK
SHRTWV AND SFC MOVES THROUGH UPPER MI. EVEN THOUGH MOISTURE IS
LIMITED...SUCH WEAK DISTURBANCES IN THE BROAD CYCLONIC FLOW PATTERN
HAVE OFTEN MANAGED TO SUPPORT ISOLATED LIGHT SHOWERS.
HOWEVER...CONFIDENCE IN TIMING/POSITION OF ANY PCPN IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM EDT SUN AUG 11 2013
A QUIET WEEK IS IN THE MAKING FOR UPPER MICHIGAN AS HIGH PRESSURE
ANCHORS ITSELF OVER THE WESTERN GREAT LAKES. MOSTLY CLEAR SKIES
SHOULD BE THE RULE...THOUGH A SERIES OF WEAK SHORTWAVES COULD BE A
BIT PESKY WITH CLOUDS AROUND MID-WEEK. TEMPERATURES WILL SLOWLY WARM
TO NEAR NORMAL...WITH SEVERAL CHILLY NIGHTS
EXPECTED...ESPECIALLY TUESDAY NIGHT.
MONDAY AND MONDAY NIGHT...THE MAIN AXIS OF AN EASTERN CANADIAN
TROUGH WILL BE APPROACHING THE AREA AT THE START OF THE PERIOD.
MODEL GUIDANCE HAS STRUGGLED WITH MAINTAINING A STEADY APPROACH TO
THE STRUCTURE OF THIS TROUGH AXIS. THERE ARE SEVERAL DISTINCT AXES
EMBEDDED IN THE MAIN TROUGH...AND EACH SHOULD SWING THROUGH THE CWA
IN ABOUT 12 HOUR INTERVALS STARTING MONDAY MORNING. THE MAIN PLAYER
IN THIS SERIES IS CURRENTLY MOVING SSW INTO FAR NORTHWEST HUDSON BAY
AROUND THE WESTERN PERIPHERY OF AN IMPRESSIVE VORT MAX OVER CENTRAL
HUDSON BAY. BOTH ARE CLEARLY APPARENT IN WATER VAPOR SAT...SO SEE NO
REASON TO QUESTION MODEL PERFORMANCE WITH TIMING. THE TROUGH SHOULD
BE OVER WESTERN LAKE SUPERIOR BY 18Z MONDAY...AND EASTERN UPPER MI
AT 00Z TUESDAY. MID-LEVEL SUPPORT WILL BE PRESENT WITH MODEST H5
Q-VECTOR CONVERGENCE AND H7 FRONTOGENESIS. A SUBSIDENCE INVERSION
AROUND 600MB BEHIND SUNDAYS SYSTEM AND DRIER AIR BEHIND THE SFC
FRONT WILL LIMIT PCPN COVERAGE. LAKE BREEZE CONVERGENCE WILL ASSIST
PCPN DEVELOPMENT...BUT STABILIZING NW GRADIENT FLOW SHOULD CONFINE
BEST COVERAGE TO THE SOUTH-CENTRAL AND ALONG LAKE MI. THUNDER
POTENTIAL WILL BE MINIMAL WITH MUCAPE STRUGGLING TO REACH 500 J/KG
NORTH OF GRB. MOST OF THIS CAPE WILL BE BELOW THE 0C LEVEL...SO KEPT
THUNDER AT SLIGHT CHANCE OVER JUST THE SOUTH CENTRAL CWA.
MONDAY NIGHT AND TUESDAY...ANY PRECIP WILL DIMINISH WITH THE PASSAGE
OF AN ASSOCIATED SFC TROUGH AND LOSS OF DAYTIME HEATING MONDAY
EVENING. A SECOND MID-LEVEL WAVE CLOSER ASSOCIATED WITH THE MAIN
TROUGH AXIS WILL BE CROSSING THE CWA BY 12Z TUESDAY. THE NAM AND
ECMWF ARE A BIT SLOWER WITH THIS TROUGH AND ACTUALLY KICK OFF SOME
LIGHT SHOWER ACTIVITY ACROSS THE INTERIOR CENTRAL AND EAST TUESDAY
MORNING. WITH THE ATMOSPHERE QUITE DEPLETED OF MOISTURE AS NOTED BY
PWATS OF ONLY 0.7 INCHES...DO NOT EXPECT MUCH MORE THAN SOME
MID-LEVEL CLOUDINESS WITH MAYBE A FEW SPRINKLES. THIS DOES MAKE MIN
TEMPS FOR MONDAY NIGHT A LITTLE HARDER TO PIN DOWN. GIVEN THE
UNCERTAINTY IN MID-CLOUD COVER...OPTED NOT TO CHANGE MUCH AND LEAVE
TEMPS RANGING FROM THE MID 40S INTERIOR WEST TO THE LOW 50S ALONG
THE SHORE. QUITE A COOL TUESDAY WILL FOLLOW UNDER H8 TEMPS OF ONLY 4
TO 7C...COOLEST EAST. MIXING SHOULD REACH THE H8 LEVEL...SO TEMPS
ARE EXPECTED TO APPROACH 70F SOUTH CENTRAL. AN EXCELLENT MODIS SST
CAPTURE TODAY SHOWS LAKE TEMPS AROUND 50F IN THE NORTHERN OPEN
WATERS...AND MID 50S IN THE REMAINDER OF THE OPEN WATERS. SO EVEN
WITH A NORTH WIND...THE COASTAL AREAS SHOULD BE ABLE TO BREAK INTO
THE LOW 60S.
TUESDAY NIGHT THROUGH THURSDAY...SFC HIGH PRESSURE WILL SETTLE OVER
WESTERN UPPER MI TUESDAY NIGHT AS MID-LEVEL RIDGING ATTEMPTS TO
BUILD EASTWARD INTO THE UPPER MS VALLEY. LOW PWAT UNDER 0.5 INCHES
AND LIGHT WINDS WILL LEAD TO EXCELLENT RADIATIONAL COOLING.
CONTINUED USING A BLEND OF GUIDANCE THAT HAS PERFORMED WELL ON
SIMILAR NIGHTS OVER THE PAST FEW WEEKS. EXPECT 40S FOR ALL BUT THE
IMMEDIATE SHORE. SOME TYPICAL INTERIOR WEST COLD SPOTS COULD EVEN
SEE UPPER 30S.
A THIRD WAVE WILL SKIM THE NE CWA WEDNESDAY MORNING. LITTLE MOISTURE
AND MINIMAL LIFT WILL BRING ONLY SCATTERED MID-CLOUDS. ANOTHER WAVE
WILL FOLLOW THE SAME TRACK ON THURSDAY...BUT WILL SUCCUMB TO THE
SAME LIMITING FACTORS. CLOUDINESS SHOULD BE A LITTLE MORE AS LIMITED
MOISTURE RETURN BEGINS ON THE BACKSIDE THE SFC RIDGE.
FRIDAY AND SATURDAY...MODEL GUIDANCE IS SHOWING A TROUGH DROPPING SE
OVER NORTHERN ONTARIO LATE FRIDAY INTO SATURDAY. THOUGH GUIDANCE IS
SHOWING MORE CONSISTENCY...WILL CONTINUE CONSENSUS APPROACH TO
PRECIP CHANCES FOR NOW...WHICH SHOULD BE LIMITED TO SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 131 PM EDT SUN AUG 11 2013
EXPECT VFR CONDITIONS THIS FCST PERIOD AT ALL THREE TAF SITES. A
PASSING DISTURBANCE MAY CAUSE SOME -SHRA THIS AFTN IN THE PRESENCE
OF DAYTIME HEATING AT SAW AND PERHAPS IWD...BUT CONFIDENCE IS TOO LOW
TO INCLUDE MORE THAN VCSH IN THE TAFS. ANY -SHRA WILL END BY
SUNSET WITH THE ONSET OF NOCTURNAL COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EDT SUN AUG 11 2013
A SERIES OF WEAK TROUGHS WILL MOVE THROUGH LAKE SUPERIOR THROUGH
MONDAY. HOWEVER...WINDS ARE EXPECTED TO REMAIN LESS THAN 20 KNOTS.
HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT LAKES TUESDAY
THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
734 AM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EDT SUN AUG 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WRLY FLOW THROUGH THE NRN
GREAT LAKES ON THE SRN FLANK OF A MID/UPPER LEVEL TROUGH EXTENDING
FROM HUDSON BAY TO NEW FOUNDLAND. A WELL-DEFINED UPSTREAM SHORTWAVE
TROUGH LOCATED NEAR THE NW CORNER OF MN SUPPORTED A BAND OF LIGHT
SHOWERS OVER N CNTRL MN. THE HEAVIER SHRA/TSRA REMAINED WELL TO THE
SOUTH FROM SE SD AND SW MN INTO NW IA ALONG THE 850 MB FRONT. AT THE
SFC...A WEAK TROUGH AHEAD OF THE MID LEVEL SHRTWV EXTENDED FROM NEAR
CYQT NRN MN. IR LOOP SHOWED MAINLY CLEAR SKIES OVER UPPER MI WITH
MID CLOUDS APPROACHING FROM NE MN.
TODAY...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE TIMING OF
THE SHRTWV ACROSS THE AREA BRINGING THIS FEATURE INTO CNTRL UPPER MI
AROUND 18Z AND QUICKLY TO LAKE HURON BY 00Z. THE COMBINATION OF THE
WEAK 700-300 MB QVECTOR CONV WITH THE SHRTWV AND LOW LEVEL CONV
ALONG THE TROUGH AND LAKE BREEZE BOUNDARIES SHOULD BE ENOUGH TO
SUPPORT AT LEAST SUPPORT ISOLD/SCT PCPN. MLCAPE VALUES TO AROUND 400
J/KG...PER NAM...WILL BE MARGINAL FOR TSRA BUT WITH THE ARRIVAL OF
THE SHRTWV DURING PEAK HEATING ISOLD TSRA WILL ALSO BE POSSIBLE.
TONIGHT...ANY SHRA/TSRA THAT DEVELOP DURING THE AFTERNOON WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING AND THE DEPARTURE OF THE
SHRTWV. A SLIGHT CHANCE FOR SHOWERS WAS MENTIONED AS ANOTHER WEAK
SHRTWV AND SFC MOVES THROUGH UPPER MI. EVEN THOUGH MOISTURE IS
LIMITED...SUCH WEAK DISTURBANCES IN THE BROAD CYCLONIC FLOW PATTERN
HAVE OFTEN MANAGED TO SUPPORT ISOLATED LIGHT SHOWERS.
HOWEVER...CONFIDENCE IN TIMING/POSITION OF ANY PCPN IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM EDT SUN AUG 11 2013
A QUIET WEEK IS IN THE MAKING FOR UPPER MICHIGAN AS HIGH PRESSURE
ANCHORS ITSELF OVER THE WESTERN GREAT LAKES. MOSTLY CLEAR SKIES
SHOULD BE THE RULE...THOUGH A SERIES OF WEAK SHORTWAVES COULD BE A
BIT PESKY WITH CLOUDS AROUND MID-WEEK. TEMPERATURES WILL SLOWLY WARM
TO NEAR NORMAL...WITH SEVERAL CHILLY NIGHTS
EXPECTED...ESPECIALLY TUESDAY NIGHT.
MONDAY AND MONDAY NIGHT...THE MAIN AXIS OF AN EASTERN CANADIAN
TROUGH WILL BE APPROACHING THE AREA AT THE START OF THE PERIOD.
MODEL GUIDANCE HAS STRUGGLED WITH MAINTAINING A STEADY APPROACH TO
THE STRUCTURE OF THIS TROUGH AXIS. THERE ARE SEVERAL DISTINCT AXES
EMBEDDED IN THE MAIN TROUGH...AND EACH SHOULD SWING THROUGH THE CWA
IN ABOUT 12 HOUR INTERVALS STARTING MONDAY MORNING. THE MAIN PLAYER
IN THIS SERIES IS CURRENTLY MOVING SSW INTO FAR NORTHWEST HUDSON BAY
AROUND THE WESTERN PERIPHERY OF AN IMPRESSIVE VORT MAX OVER CENTRAL
HUDSON BAY. BOTH ARE CLEARLY APPARENT IN WATER VAPOR SAT...SO SEE NO
REASON TO QUESTION MODEL PERFORMANCE WITH TIMING. THE TROUGH SHOULD
BE OVER WESTERN LAKE SUPERIOR BY 18Z MONDAY...AND EASTERN UPPER MI
AT 00Z TUESDAY. MID-LEVEL SUPPORT WILL BE PRESENT WITH MODEST H5
Q-VECTOR CONVERGENCE AND H7 FRONTOGENESIS. A SUBSIDENCE INVERSION
AROUND 600MB BEHIND SUNDAYS SYSTEM AND DRIER AIR BEHIND THE SFC
FRONT WILL LIMIT PCPN COVERAGE. LAKE BREEZE CONVERGENCE WILL ASSIST
PCPN DEVELOPMENT...BUT STABILIZING NW GRADIENT FLOW SHOULD CONFINE
BEST COVERAGE TO THE SOUTH-CENTRAL AND ALONG LAKE MI. THUNDER
POTENTIAL WILL BE MINIMAL WITH MUCAPE STRUGGLING TO REACH 500 J/KG
NORTH OF GRB. MOST OF THIS CAPE WILL BE BELOW THE 0C LEVEL...SO KEPT
THUNDER AT SLIGHT CHANCE OVER JUST THE SOUTH CENTRAL CWA.
MONDAY NIGHT AND TUESDAY...ANY PRECIP WILL DIMINISH WITH THE PASSAGE
OF AN ASSOCIATED SFC TROUGH AND LOSS OF DAYTIME HEATING MONDAY
EVENING. A SECOND MID-LEVEL WAVE CLOSER ASSOCIATED WITH THE MAIN
TROUGH AXIS WILL BE CROSSING THE CWA BY 12Z TUESDAY. THE NAM AND
ECMWF ARE A BIT SLOWER WITH THIS TROUGH AND ACTUALLY KICK OFF SOME
LIGHT SHOWER ACTIVITY ACROSS THE INTERIOR CENTRAL AND EAST TUESDAY
MORNING. WITH THE ATMOSPHERE QUITE DEPLETED OF MOISTURE AS NOTED BY
PWATS OF ONLY 0.7 INCHES...DO NOT EXPECT MUCH MORE THAN SOME
MID-LEVEL CLOUDINESS WITH MAYBE A FEW SPRINKLES. THIS DOES MAKE MIN
TEMPS FOR MONDAY NIGHT A LITTLE HARDER TO PIN DOWN. GIVEN THE
UNCERTAINTY IN MID-CLOUD COVER...OPTED NOT TO CHANGE MUCH AND LEAVE
TEMPS RANGING FROM THE MID 40S INTERIOR WEST TO THE LOW 50S ALONG
THE SHORE. QUITE A COOL TUESDAY WILL FOLLOW UNDER H8 TEMPS OF ONLY 4
TO 7C...COOLEST EAST. MIXING SHOULD REACH THE H8 LEVEL...SO TEMPS
ARE EXPECTED TO APPROACH 70F SOUTH CENTRAL. AN EXCELLENT MODIS SST
CAPTURE TODAY SHOWS LAKE TEMPS AROUND 50F IN THE NORTHERN OPEN
WATERS...AND MID 50S IN THE REMAINDER OF THE OPEN WATERS. SO EVEN
WITH A NORTH WIND...THE COASTAL AREAS SHOULD BE ABLE TO BREAK INTO
THE LOW 60S.
TUESDAY NIGHT THROUGH THURSDAY...SFC HIGH PRESSURE WILL SETTLE OVER
WESTERN UPPER MI TUESDAY NIGHT AS MID-LEVEL RIDGING ATTEMPTS TO
BUILD EASTWARD INTO THE UPPER MS VALLEY. LOW PWAT UNDER 0.5 INCHES
AND LIGHT WINDS WILL LEAD TO EXCELLENT RADIATIONAL COOLING.
CONTINUED USING A BLEND OF GUIDANCE THAT HAS PERFORMED WELL ON
SIMILAR NIGHTS OVER THE PAST FEW WEEKS. EXPECT 40S FOR ALL BUT THE
IMMEDIATE SHORE. SOME TYPICAL INTERIOR WEST COLD SPOTS COULD EVEN
SEE UPPER 30S.
A THIRD WAVE WILL SKIM THE NE CWA WEDNESDAY MORNING. LITTLE MOISTURE
AND MINIMAL LIFT WILL BRING ONLY SCATTERED MID-CLOUDS. ANOTHER WAVE
WILL FOLLOW THE SAME TRACK ON THURSDAY...BUT WILL SUCCUMB TO THE
SAME LIMITING FACTORS. CLOUDINESS SHOULD BE A LITTLE MORE AS LIMITED
MOISTURE RETURN BEGINS ON THE BACKSIDE THE SFC RIDGE.
FRIDAY AND SATURDAY...MODEL GUIDANCE IS SHOWING A TROUGH DROPPING SE
OVER NORTHERN ONTARIO LATE FRIDAY INTO SATURDAY. THOUGH GUIDANCE IS
SHOWING MORE CONSISTENCY...WILL CONTINUE CONSENSUS APPROACH TO
PRECIP CHANCES FOR NOW...WHICH SHOULD BE LIMITED TO SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 733 AM EDT SUN AUG 11 2013
EXPECT VFR CONDITIONS THIS FCST PERIOD AT ALL THREE TAF SITES. A
PASSING DISTURBANCE MAY CAUSE SOME -SHRA THIS AFTN IN THE PRESENCE
OF DAYTIME HEATING AT SAW AND PERHAPS IWD...BUT CONFIDENCE IS TOO LOW
TO INCLUDE MORE THAN VCSH IN THE TAFS. ANY -SHRA WILL END BY
SUNSET WITH THE ONSET OF NOCTURNAL COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EDT SUN AUG 11 2013
A SERIES OF WEAK TROUGHS WILL MOVE THROUGH LAKE SUPERIOR THROUGH
MONDAY. HOWEVER...WINDS ARE EXPECTED TO REMAIN LESS THAN 20 KNOTS.
HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT LAKES TUESDAY
THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EDT SUN AUG 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WRLY FLOW THROUGH THE NRN
GREAT LAKES ON THE SRN FLANK OF A MID/UPPER LEVEL TROUGH EXTENDING
FROM HUDSON BAY TO NEW FOUNDLAND. A WELL-DEFINED UPSTREAM SHORTWAVE
TROUGH LOCATED NEAR THE NW CORNER OF MN SUPPORTED A BAND OF LIGHT
SHOWERS OVER N CNTRL MN. THE HEAVIER SHRA/TSRA REMAINED WELL TO THE
SOUTH FROM SE SD AND SW MN INTO NW IA ALONG THE 850 MB FRONT. AT THE
SFC...A WEAK TROUGH AHEAD OF THE MID LEVEL SHRTWV EXTENDED FROM NEAR
CYQT NRN MN. IR LOOP SHOWED MAINLY CLEAR SKIES OVER UPPER MI WITH
MID CLOUDS APPROACHING FROM NE MN.
TODAY...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE TIMING OF
THE SHRTWV ACROSS THE AREA BRINGING THIS FEATURE INTO CNTRL UPPER MI
AROUND 18Z AND QUICKLY TO LAKE HURON BY 00Z. THE COMBINATION OF THE
WEAK 700-300 MB QVECTOR CONV WITH THE SHRTWV AND LOW LEVEL CONV
ALONG THE TROUGH AND LAKE BREEZE BOUNDARIES SHOULD BE ENOUGH TO
SUPPORT AT LEAST SUPPORT ISOLD/SCT PCPN. MLCAPE VALUES TO AROUND 400
J/KG...PER NAM...WILL BE MARGINAL FOR TSRA BUT WITH THE ARRIVAL OF
THE SHRTWV DURING PEAK HEATING ISOLD TSRA WILL ALSO BE POSSIBLE.
TONIGHT...ANY SHRA/TSRA THAT DEVELOP DURING THE AFTERNOON WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING AND THE DEPARTURE OF THE
SHRTWV. A SLIGHT CHANCE FOR SHOWERS WAS MENTIONED AS ANOTHER WEAK
SHRTWV AND SFC MOVES THROUGH UPPER MI. EVEN THOUGH MOISTURE IS
LIMITED...SUCH WEAK DISTURBANCES IN THE BROAD CYCLONIC FLOW PATTERN
HAVE OFTEN MANAGED TO SUPPORT ISOLATED LIGHT SHOWERS.
HOWEVER...CONFIDENCE IN TIMING/POSITION OF ANY PCPN IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM EDT SUN AUG 11 2013
A QUIET WEEK IS IN THE MAKING FOR UPPER MICHIGAN AS HIGH PRESSURE
ANCHORS ITSELF OVER THE WESTERN GREAT LAKES. MOSTLY CLEAR SKIES
SHOULD BE THE RULE...THOUGH A SERIES OF WEAK SHORTWAVES COULD BE A
BIT PESKY WITH CLOUDS AROUND MID-WEEK. TEMPERATURES WILL SLOWLY WARM
TO NEAR NORMAL...WITH SEVERAL CHILLY NIGHTS
EXPECTED...ESPECIALLY TUESDAY NIGHT.
MONDAY AND MONDAY NIGHT...THE MAIN AXIS OF AN EASTERN CANADIAN
TROUGH WILL BE APPROACHING THE AREA AT THE START OF THE PERIOD.
MODEL GUIDANCE HAS STRUGGLED WITH MAINTAINING A STEADY APPROACH TO
THE STRUCTURE OF THIS TROUGH AXIS. THERE ARE SEVERAL DISTINCT AXES
EMBEDDED IN THE MAIN TROUGH...AND EACH SHOULD SWING THROUGH THE CWA
IN ABOUT 12 HOUR INTERVALS STARTING MONDAY MORNING. THE MAIN PLAYER
IN THIS SERIES IS CURRENTLY MOVING SSW INTO FAR NORTHWEST HUDSON BAY
AROUND THE WESTERN PERIPHERY OF AN IMPRESSIVE VORT MAX OVER CENTRAL
HUDSON BAY. BOTH ARE CLEARLY APPARENT IN WATER VAPOR SAT...SO SEE NO
REASON TO QUESTION MODEL PERFORMANCE WITH TIMING. THE TROUGH SHOULD
BE OVER WESTERN LAKE SUPERIOR BY 18Z MONDAY...AND EASTERN UPPER MI
AT 00Z TUESDAY. MID-LEVEL SUPPORT WILL BE PRESENT WITH MODEST H5
Q-VECTOR CONVERGENCE AND H7 FRONTOGENESIS. A SUBSIDENCE INVERSION
AROUND 600MB BEHIND SUNDAYS SYSTEM AND DRIER AIR BEHIND THE SFC
FRONT WILL LIMIT PCPN COVERAGE. LAKE BREEZE CONVERGENCE WILL ASSIST
PCPN DEVELOPMENT...BUT STABILIZING NW GRADIENT FLOW SHOULD CONFINE
BEST COVERAGE TO THE SOUTH-CENTRAL AND ALONG LAKE MI. THUNDER
POTENTIAL WILL BE MINIMAL WITH MUCAPE STRUGGLING TO REACH 500 J/KG
NORTH OF GRB. MOST OF THIS CAPE WILL BE BELOW THE 0C LEVEL...SO KEPT
THUNDER AT SLIGHT CHANCE OVER JUST THE SOUTH CENTRAL CWA.
MONDAY NIGHT AND TUESDAY...ANY PRECIP WILL DIMINISH WITH THE PASSAGE
OF AN ASSOCIATED SFC TROUGH AND LOSS OF DAYTIME HEATING MONDAY
EVENING. A SECOND MID-LEVEL WAVE CLOSER ASSOCIATED WITH THE MAIN
TROUGH AXIS WILL BE CROSSING THE CWA BY 12Z TUESDAY. THE NAM AND
ECMWF ARE A BIT SLOWER WITH THIS TROUGH AND ACTUALLY KICK OFF SOME
LIGHT SHOWER ACTIVITY ACROSS THE INTERIOR CENTRAL AND EAST TUESDAY
MORNING. WITH THE ATMOSPHERE QUITE DEPLETED OF MOISTURE AS NOTED BY
PWATS OF ONLY 0.7 INCHES...DO NOT EXPECT MUCH MORE THAN SOME
MID-LEVEL CLOUDINESS WITH MAYBE A FEW SPRINKLES. THIS DOES MAKE MIN
TEMPS FOR MONDAY NIGHT A LITTLE HARDER TO PIN DOWN. GIVEN THE
UNCERTAINTY IN MID-CLOUD COVER...OPTED NOT TO CHANGE MUCH AND LEAVE
TEMPS RANGING FROM THE MID 40S INTERIOR WEST TO THE LOW 50S ALONG
THE SHORE. QUITE A COOL TUESDAY WILL FOLLOW UNDER H8 TEMPS OF ONLY 4
TO 7C...COOLEST EAST. MIXING SHOULD REACH THE H8 LEVEL...SO TEMPS
ARE EXPECTED TO APPROACH 70F SOUTH CENTRAL. AN EXCELLENT MODIS SST
CAPTURE TODAY SHOWS LAKE TEMPS AROUND 50F IN THE NORTHERN OPEN
WATERS...AND MID 50S IN THE REMAINDER OF THE OPEN WATERS. SO EVEN
WITH A NORTH WIND...THE COASTAL AREAS SHOULD BE ABLE TO BREAK INTO
THE LOW 60S.
TUESDAY NIGHT THROUGH THURSDAY...SFC HIGH PRESSURE WILL SETTLE OVER
WESTERN UPPER MI TUESDAY NIGHT AS MID-LEVEL RIDGING ATTEMPTS TO
BUILD EASTWARD INTO THE UPPER MS VALLEY. LOW PWAT UNDER 0.5 INCHES
AND LIGHT WINDS WILL LEAD TO EXCELLENT RADIATIONAL COOLING.
CONTINUED USING A BLEND OF GUIDANCE THAT HAS PERFORMED WELL ON
SIMILAR NIGHTS OVER THE PAST FEW WEEKS. EXPECT 40S FOR ALL BUT THE
IMMEDIATE SHORE. SOME TYPICAL INTERIOR WEST COLD SPOTS COULD EVEN
SEE UPPER 30S.
A THIRD WAVE WILL SKIM THE NE CWA WEDNESDAY MORNING. LITTLE MOISTURE
AND MINIMAL LIFT WILL BRING ONLY SCATTERED MID-CLOUDS. ANOTHER WAVE
WILL FOLLOW THE SAME TRACK ON THURSDAY...BUT WILL SUCCUMB TO THE
SAME LIMITING FACTORS. CLOUDINESS SHOULD BE A LITTLE MORE AS LIMITED
MOISTURE RETURN BEGINS ON THE BACKSIDE THE SFC RIDGE.
FRIDAY AND SATURDAY...MODEL GUIDANCE IS SHOWING A TROUGH DROPPING SE
OVER NORTHERN ONTARIO LATE FRIDAY INTO SATURDAY. THOUGH GUIDANCE IS
SHOWING MORE CONSISTENCY...WILL CONTINUE CONSENSUS APPROACH TO
PRECIP CHANCES FOR NOW...WHICH SHOULD BE LIMITED TO SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 124 AM EDT SUN AUG 11 2013
EXCEPT FOR SOME SHALLOW GROUND FOG AT IWD EARLY THIS MRNG...EXPECT
VFR CONDITIONS THIS FCST PERIOD AT ALL THREE TAF SITES. A PASSING
DISTURBANCE MAY CAUSE SOME -SHRA THIS AFTN IN THE PRESENCE OF
DAYTIME HEATING AT SAW AND PERHAPS IWD...BUT CONFIDENCE IS TOO LO TO
INCLUDE MORE THAN VCSH IN THE TAFS ATTM. ANY -SHRA WL END BY SUNSET
WITH THE ONSET OF NOCTURNAL COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EDT SUN AUG 11 2013
A SERIES OF WEAK TROUGHS WILL MOVE THROUGH LAKE SUPERIOR THROUGH
MONDAY. HOWEVER...WINDS ARE EXPECTED TO REMAIN LESS THAN 20 KNOTS.
HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT LAKES TUESDAY
THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1230 PM CDT SUN AUG 11 2013
.AVIATION...18Z TAF ISSUANCE...
GENERALLY VFR CIGS THROUGH THIS AFTERNOON WITH ISOLATED RAIN
SHOWERS AND EVEN A FEW VERY ISOLATED T-STORMS. VSBYS COULD DROP TO
MVFR TEMPORARILY IN THE BRIEF HEAVY SHOWERS. WINDS WILL REMAIN
LIGHT FROM THE N/NW...EXCEPT AROUND THE PERIPHERY OF LAKE
SUPERIOR...WITH A LIGHT LAKE BREEZE. COULD SEE PATCHY FOG DEVELOP
LATE TONIGHT WHERE MID/HIGH CLOUDS CLEAR OFF.
&&
.PREV DISCUSSION... /ISSUED 1027 AM CDT SUN AUG 11 2013/
UPDATE...
THE FOCUS ON THIS UPDATE IS ON CLOUD COVER AND PCPN TRENDS THROUGH
THIS EVENING. THE MODELS ARE SUGGESTING THAT SCATTERED/BROKEN
CUMULUS CLOUDS WILL DEVELOP IN OUR COOL WNW FLOW EARLY THIS
AFTERNOON WHEN WE GET CLOSER TO PEAK HEATING AND AFTER SOME OF THE
REMAINING MID TO HIGH LEVEL CLOUDS FROM THIS MORNING DISSIPATE OR
MOVE OUT OF THE FORECAST AREA. THE HRRR AND SREF...INCLUDING SOME
OTHER MODELS...ARE SUGGESTING THERE MAY BE SOME SHOWERS AND/OR
SPRINKLES AMIDST THE SCT/BKN CUMULUS. THEREFORE...I ADDED SOME
MENTION OF SHOWERS OVER MOST OF THE NORTHLAND FOR THIS AFTERNOON.
THERE MAY ALSO BE SOME WEAK THUNDERSHOWERS.
AVIATION...12Z TAF ISSUANCE...
UPPER LEVEL SYSTEM WILL CROSS CWA TODAY WITH SHOWERS POSSIBLE AT
TIMES. CEILINGS SHOULD REMAIN VFR EXCEPT NEAR KINL WHERE MVFR
MAY DEVELOP THIS MORNING AND INTO THE EARLY AFTERNOON. SFC HIGH
BUILDS INTO REGION OVERNIGHT HOWEVER MAY SEE LINGERING VFR
CEILINGS NEAR 5K TO 7K FEET ACROSS SOME TERMINALS.
PREV DISCUSSION... /ISSUED 703 AM CDT SUN AUG 11 2013/
UPDATE....
SHOWERS ARE SLIGHTLY MORE NUMEROUS THAN THOUGHT SO MADE SOME
SLIGHT ADJUSTMENTS TO RAISE POPS SLIGHTLY.
PREV DISCUSSION... /ISSUED 330 AM CDT SUN AUG 11 2013/
SHORT TERM...
THE UPPER LEVEL LOW PRESSURE TROUGH CENTERED OVR EASTERN CANADA AND
STRETCHING ACROSS THE GREAT LAKES WILL PRODUCE SOME MORE SHOWERS
TODAY. A COUPLE MORE S/WVS WILL ROTATE THROUGH THE TROF TODAY.
CURRENT WV LOOP DEPICTS THE S/WV INTO NWRN MN.. AND HAS RESULTED
IN SOME VERY LIGHT SHOWERS ACROSS NORTHERN MN. THIS WAVE WILL
ROTATE SEWRD ACROSS THE CWA...AND HAVE GIVEN SMALL POPS FOR THE
REGION. EXPECT SHOWERS TO BE MAINLY THIS MORNING IN THE FAR
NORTH...AND NOT BEGIN TIL MID TO LATE MORNING IN NWRN WI. HAVE
INTRODUCED SOME THUNDER LATER TODAY WITH FAIRLY STEEP LOW LEVEL
LAPSE RATES LATER THIS MORNING AND AFTERNOON AND LI`S DOWN TO -2.
EXTENDED...MONDAY THROUGH SATURDAY...
AN UNUSUALLY STRONG MID LVL VORTEX OVER CTRL ONTARIO WILL PUSH A SFC
COLD FRONT ACROSS THE REGION MONDAY. A CYCLONICALLY CURVED FLOW
COMBINED WITH SUFFICIENT DEEP LAYER MOISTURE WILL CREATE SHOWER
POTENTIAL OVER THE NRN/ERN PARTS OF THE CWA. FOR THE REMAINDER OF
THE WEEK THE ANOMALOUS ONTARIO MID LVL TROF WILL MOVE EAST.
INCREASING RIDGING ALOFT WILL ALLOW A LARGE SFC HIGH TO EXPAND
FROM THE SRN PLAINS OF CANADA INTO THE LOWER GT LAKES. A PERIOD OF
QUIET WX IS EXPECTED TUES THROUGH THUR AS SUBSIDENCE SFC/ALOFT
DOMINATES MOST OF THE REGION. THE ONLY POSSIBLE EXCEPTION WOULD BE
OVER ERN ARROWHEAD CLOSER TO EASTERN VORTEX. CONFIDENCE IN FCST
DECREASES BY FRIDAY AS GEM/GFS/ECMWF DISAGREE ON MID LVL FLOW
EVOLUTION. AS WAS THE CASE IN PREVIOUS GRIDS/FCST WILL CARRY SOME
LOW POPS BEGINNING FRIDAY...AND INTO THE WEEKEND. THE CONSENSUS IS
THAT A WARMING TREND IS APPEARING MORE LIKELY FOR THE WEEKEND AS
UPPER HEIGHTS BUILD AND 925/85 TEMP VALUES RISE ABOVE WHAT WE HAVE
EXPERIENCED IN A WHILE. 85H MSTR TRANSPORT AMONG THE MED RANGE MDLS
SUGGESTS ENOUGH MOISTURE WILL BE AVAILABLE FOR CONVECTION
SAT/SUNDAY. OVERALL SYNOPTIC SCALE PATTERN THIS WEEKEND WOULD
SUGGEST INCREASING POSSIBILITY OF MCS GENERATION OVER SRN
SASK/MAN...MOVING SE TOWARDS CWA. TOO MANY UNCERTAINTIES TO
HIGHLIGHT MAGNITUDE/AREAL COVERAGE OF POTENTIAL STRONG/SVR STORMS.
TEMPS WILL AVERAGE BLO CLIMO MOST OF THE WEEK AND THEN NEAR/ABOVE
CLIMO FOR THE WEEKEND.
&&
.POINT TEMPS/POPS...
DLH 55 72 49 69 / 10 10 0 0
INL 49 71 45 70 / 20 20 0 0
BRD 51 76 50 74 / 10 10 0 0
HYR 52 74 47 72 / 10 10 0 10
ASX 53 71 48 68 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
1027 AM CDT SUN AUG 11 2013
.UPDATE...
THE FOCUS ON THIS UPDATE IS ON CLOUD COVER AND PCPN TRENDS THROUGH
THIS EVENING. THE MODELS ARE SUGGESTING THAT SCATTERED/BROKEN
CUMULUS CLOUDS WILL DEVELOP IN OUR COOL WNW FLOW EARLY THIS
AFTERNOON WHEN WE GET CLOSER TO PEAK HEATING AND AFTER SOME OF THE
REMAINING MID TO HIGH LEVEL CLOUDS FROM THIS MORNING DISSIPATE OR
MOVE OUT OF THE FORECAST AREA. THE HRRR AND SREF...INCLUDING SOME
OTHER MODELS...ARE SUGGESTING THERE MAY BE SOME SHOWERS AND/OR
SPRINKLES AMIDST THE SCT/BKN CUMULUS. THEREFORE...I ADDED SOME
MENTION OF SHOWERS OVER MOST OF THE NORTHLAND FOR THIS AFTERNOON.
THERE MAY ALSO BE SOME WEAK THUNDERSHOWERS.
.AVIATION...12Z TAF ISSUANCE...
UPPER LEVEL SYSTEM WILL CROSS CWA TODAY WITH SHOWERS POSSIBLE AT
TIMES. CEILINGS SHOULD REMAIN VFR EXCEPT NEAR KINL WHERE MVFR
MAY DEVELOP THIS MORNING AND INTO THE EARLY AFTERNOON. SFC HIGH
BUILDS INTO REGION OVERNIGHT HOWEVER MAY SEE LINGERING VFR
CEILINGS NEAR 5K TO 7K FEET ACROSS SOME TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 703 AM CDT SUN AUG 11 2013/
UPDATE....
SHOWERS ARE SLIGHTLY MORE NUMEROUS THAN THOUGHT SO MADE SOME
SLIGHT ADJUSTMENTS TO RAISE POPS SLIGHTLY.
PREV DISCUSSION... /ISSUED 330 AM CDT SUN AUG 11 2013/
SHORT TERM...
THE UPPER LEVEL LOW PRESSURE TROUGH CENTERED OVR EASTERN CANADA AND
STRETCHING ACROSS THE GREAT LAKES WILL PRODUCE SOME MORE SHOWERS
TODAY. A COUPLE MORE S/WVS WILL ROTATE THROUGH THE TROF TODAY.
CURRENT WV LOOP DEPICTS THE S/WV INTO NWRN MN.. AND HAS RESULTED
IN SOME VERY LIGHT SHOWERS ACROSS NORTHERN MN. THIS WAVE WILL
ROTATE SEWRD ACROSS THE CWA...AND HAVE GIVEN SMALL POPS FOR THE
REGION. EXPECT SHOWERS TO BE MAINLY THIS MORNING IN THE FAR
NORTH...AND NOT BEGIN TIL MID TO LATE MORNING IN NWRN WI. HAVE
INTRODUCED SOME THUNDER LATER TODAY WITH FAIRLY STEEP LOW LEVEL
LAPSE RATES LATER THIS MORNING AND AFTERNOON AND LI`S DOWN TO -2.
EXTENDED...MONDAY THROUGH SATURDAY...
AN UNUSUALLY STRONG MID LVL VORTEX OVER CTRL ONTARIO WILL PUSH A SFC
COLD FRONT ACROSS THE REGION MONDAY. A CYCLONICALLY CURVED FLOW
COMBINED WITH SUFFICIENT DEEP LAYER MOISTURE WILL CREATE SHOWER
POTENTIAL OVER THE NRN/ERN PARTS OF THE CWA. FOR THE REMAINDER OF
THE WEEK THE ANOMALOUS ONTARIO MID LVL TROF WILL MOVE EAST.
INCREASING RIDGING ALOFT WILL ALLOW A LARGE SFC HIGH TO EXPAND
FROM THE SRN PLAINS OF CANADA INTO THE LOWER GT LAKES. A PERIOD OF
QUIET WX IS EXPECTED TUES THROUGH THUR AS SUBSIDENCE SFC/ALOFT
DOMINATES MOST OF THE REGION. THE ONLY POSSIBLE EXCEPTION WOULD BE
OVER ERN ARROWHEAD CLOSER TO EASTERN VORTEX. CONFIDENCE IN FCST
DECREASES BY FRIDAY AS GEM/GFS/ECMWF DISAGREE ON MID LVL FLOW
EVOLUTION. AS WAS THE CASE IN PREVIOUS GRIDS/FCST WILL CARRY SOME
LOW POPS BEGINNING FRIDAY...AND INTO THE WEEKEND. THE CONSENSUS IS
THAT A WARMING TREND IS APPEARING MORE LIKELY FOR THE WEEKEND AS
UPPER HEIGHTS BUILD AND 925/85 TEMP VALUES RISE ABOVE WHAT WE HAVE
EXPERIENCED IN A WHILE. 85H MSTR TRANSPORT AMONG THE MED RANGE MDLS
SUGGESTS ENOUGH MOISTURE WILL BE AVAILABLE FOR CONVECTION
SAT/SUNDAY. OVERALL SYNOPTIC SCALE PATTERN THIS WEEKEND WOULD
SUGGEST INCREASING POSSIBILITY OF MCS GENERATION OVER SRN
SASK/MAN...MOVING SE TOWARDS CWA. TOO MANY UNCERTAINTIES TO
HIGHLIGHT MAGNITUDE/AREAL COVERAGE OF POTENTIAL STRONG/SVR STORMS.
TEMPS WILL AVERAGE BLO CLIMO MOST OF THE WEEK AND THEN NEAR/ABOVE
CLIMO FOR THE WEEKEND.
&&
.POINT TEMPS/POPS...
DLH 76 54 72 49 / 20 10 10 0
INL 71 48 71 45 / 30 20 20 0
BRD 78 52 76 50 / 20 10 10 0
HYR 76 50 74 47 / 20 10 10 0
ASX 76 52 71 48 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
931 PM CDT MON AUG 12 2013
.DISCUSSION...A LINE OF CONVECTION CONTINUES TO MOVE ESELY ACROSS
NWRN PORTIONS OF THE CWA THIS EVENING. THESE STORMS HAVE BEEN STRONG
AT TIMES...NECESSITATING A FEW SPS`S. BUT WITH THE LOSS OF DAYTIME
INSTABILITY...THE GENERAL EXPECTATION IS FOR THE INTENSITY OF THESE
STORMS TO WANE. HOWEVER AT LEAST SOME ACTIVITY MAY PERSIST INTO THE
NIGHT. LATEST HRRR RUNS SUGGEST AT LEAST SOME SHOWERS AND POSSIBLY A
STORM COULD GET AS FAR SOUTH AS THE I-20 CORRIDOR AND LINGER BEYOND
MIDNIGHT. THE FORECAST WILL BE UPDATED TO REALIGN WX GRIDS TO
REFLECT THIS THINKING. ALSO TOOK OUT RAIN CHANCES SOUTH OF I-20 IN
AREAS THAT WERE WORKED OVER BY CONVECTION DURING THE LATE AFTERNOON
AND EVENING HOURS. UPDATED PRODUCTS ARE CURRENTLY BEING SHIPPED OUT.
/DL/
&&
.AVIATION...THUNDERSTORM ACTIVITY WILL DIMINISH AS WE GO THROUGH MID
TO LATE EVENING. MOST TAF SITES HAVE RECEIVED OR WILL RECEIVE SOME
RAINFALL THIS EVENING AND THIS SHOULD HELP TO SUPPORT MVFR TO
PERHAPS IFR FOG/STRATUS PRODUCTION LATE TONIGHT AND EARLY TUESDAY
MORNING. ANY FOG/STRATUS SHOULD MIX OUT DURING THE MID MORNING HOURS
WITH MOSTLY VFR CONDITIONS ANTICIPATED FROM LATE TUESDAY MORNING
THROUGH AFTERNOON. ANOTHER ROUND OF THUNDERSTORM ACTIVITY IS LIKELY
AT MOST SITES FROM TUESDAY AFTERNOON INTO TUESDAY EVENING. /EC/
&&
.PREV DISCUSSION... /ISSUED AT 330 PM CDT MON AUG 12 2013/
SHORT TERM...THROUGH WEDNESDAY NIGHT...
AFTERNOON WATER VAPOR IMAGERY SHOWED A SHORTWAVE DROPPING OUT OF
CANADA AND OVER THE NORTHERN PLAINS. THIS AND SEVERAL OTHER SHORT
WAVES WILL HELP DEEPEN AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS
THROUGH WEDNESDAY. THIS WL RESULT IN NORTHWEST FLOW ALOFT OVER OUR
REGION TUESDAY THROUGH WEDNESDAY NIGHT. THIS WILL SUPPORT THE
SOUTHWARD DRIFT OF A WEAK COLD FRONT INTO OUR CWA TUESDAY. THIS
FRONTAL BOUNDARY WILL BECOME THE FOCUS FOR DAILY CONVECTION.
COME TUESDAY AFTERNOON SCATTERED TO NUMEROUS STORMS ARE EXPECTED TO
DEVELOP ACROSS OUR CWA. FORECAST SOUNDINGS SUGGEST A LITTLE MORE
FAVORABLE POTENTIAL FOR A STRONG STORM OR TWO...ESPECIALLY ALONG THE
HIGHWAY 82 CORRIDOR WHERE THE BOUNDARY IS EXPECTED. PWS WILL BE
ABOVE TWO INCHES AND STORMS TRAINING ALONG AND AHEAD OF THE BOUNDARY
WILL LIKELY PRODUCE HEAVY DOWNPOURS. MODELS ARE SHOWING POTENTIAL
RAINFALL OF TWO TO FOUR INCHES ACROSS THE NORTH AND CENTRAL PORTIONS
OF THE AREA FROM TUESDAY MORNING THROUGH WEDNESDAY NIGHT. THE GFS
AND NAM WERE ALSO HINTING AT A POSSIBLE MCS DROPPING INTO OUR AREA
FROM THE NORTHWEST EARLY WEDNESDAY MORNING. THE FRONT IS EXPECTED TO
BE DRAPED ACROSS THE CWA FROM SOUTHEAST ARKANSAS TO EAST CENTRAL
MISSISSIPPI. SOMEWHAT COOLER AND DRIER AIR WILL FILTER INTO OUR
NORTHERN ZONES LOWERING RAINFALL CHANCES THERE.
AS THE UPPER LEVEL TROUGH DEEPENS THROUGH WEDNESDAY NIGHT...A
+1020MB HIGH WILL SETTLE FROM THE MID MISSISSIPPI AND OHIO VALLEYS
PUSHING THE WEAK COLD FRONT SOUTH OF HIGHWAY 84 BY THURSDAY MORNING.
THE PRECIPITATION DEVELOPMENT AND ASSOCIATED CLOUD COVER WILL MAKE
TEMPERATURES A LITTLE DIFFICULT THROUGH THE PERIOD. THE 12Z GFS MOS
HIGHS WERE AMONG THE HIGHEST ENSEMBLE MEMBERS AT MOST LOCATIONS
TUESDAY. HAVE CUT HIGHS SEVERAL DEGREES ACROSS THE NORTH...CLOSER TO
THE NAM MOS AND GFS ENSEMBLE MEANS. WITH THE COLD FRONT DROPPING
ACROSS OUR SOUTHERN ZONES WEDNESDAY NIGHT...LOWER 60S LOOK
REASONABLE IN THE NORTH THURSDAY MORNING. /22/
LONG TERM...SOME DRIER AIR WILL PUSH INTO THE REGION FROM THE NORTH
THURSDAY NIGHT INTO FRIDAY MORNING AS PWATS WILL BE FROM 1-1.5
INCHES. THIS WAS CONFIRMED BY AREA MODEL CROSS SECTIONS. WITH THE
FRONT BEING STATIONARY ACROSS THE SOUTH...A SERIES OF WEAK
DISTURBANCES WILL COME ACROSS THE REGION. THERE COULD BE A FEW
STRONG STORMS DURING THE PERIOD NEAR THE DECAYING FRONTAL BOUNDARY.
THIS WILL PROVIDE SOME CHANCE OF RAIN FOR THE REST OF THE PERIOD.
WITH THE LOWER PWATS DO NOT SEE THE RISK OF LOCALLY HEAVY RAINFALL
AT THIS TIME. THE UPPER TROUGH AXIS WILL DEVELOP OVER THE REGION
FROM FRIDAY THROUGH THE WEEKEND. THIS WILL BRING SOME 60S DEWPOINTS
AND TAKE A LITTLE HUMIDITY OUT OF THE AIR WITH THE SLIGHTLY MILDER
DAYS AND COOLER NIGHTS. HIGHS AFTER THE FRONT WILL BE GENERALLY IN
THE MID 80S TO LOWER 90S WITH LOWS BRINGING SOME NIGHT RELIEF OF
READINGS IN THE 60S TO AROUND 70. THIS PATTERN MAY BRING SLIGHTLY
BELOW NORMAL HIGHS AND LOWS FOR THIS TIME OF YEAR.
AS FAR AS MODEL TEMPS ARE CONCERNED ON WEDNESDAY USED A BLEND OF
COOLER EURO AND MEX TEMPS FOR HIGHS. THE EURO LOOKED TOO WARM ON
NIGHTLY LOWS. SO WENT CLOSE TO MEX TEMPS. ON DAILY HIGHS AFTER
WEDNESDAY WENT CLOSER TO SLIGHTLY WARMER MEX NUMBERS.
AS FAR AS POPS ARE CONCERNED WENT CLOSE TO MEX NUMBERS ON WEDNESDAY
INTO THURSDAY...WHICH WAS A LITTLE WETTER THAN THE EURO. FOR THE
REST OF THE WEEK THE EURO POPS WERE RATHER DRY WITH THE STATIONARY
FRONT AROUND SO WENT CLOSER TO WETTER MEX POPS./17/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DL/EC/22/17
AREA FORECAST DISCUSSION
NWS JACKSON MS
1000 AM CDT SUN AUG 11 2013
.UPDATE...MID LEVEL WEST TO EAST ORIENTED RIDGE AXIS CONTINUES
ACROSS THE CWA. SURFACE ANALYSIS STILL HAS HIGH PRESSURE OVER THE
WESTERN ATLANTIC RIDGING WEST OVER THE GULF COAST STATES. THIS LIGHT
SOUTHERLY LOW LEVEL FLOW WAS HELPING MAINTAIN OUR +2IN PW AIRMASS.
HEATING THIS MORNING WAS ON TRACK AND A CU FIELD WAS ALREADY NOTED
OVER OUR SOUTHEAST ZONES SPREADING NORTH. THIS IS WHERE HI-RES
MODELS SUGGEST CONVECTION WL INITIATE GOING INTO THE AFTERNOON.
SCATTERED COVERAGE IS STILL EXPECTED AND OVERALL FORECAST REMAINS ON
TRACK FOR TODAY. A FEW STRONG STORMS WILL BE HARD TO RULE OUT BUT
WET MICROBURST POTENTIAL WILL BE LOW AGAIN TODAY. /22/
&&
.AVIATION...CONVECTION HAS GOTTEN AN EARLY START TODAY AS SOME
ISOLATED SHOWERS HAVE DEVELOPED AND ARE LIFTING NORTH OVER EAST
CENTRAL AND SOUTHEAST MISSISSIPPI...KMEI AND KHBG. WHILE VFR
CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES THROUGH THE
COURSE OF THE DAY...SCATTERED CONVECTION IS FORECAST TO DEVELOP AS
WE HEAT UP AND OUR ATMOSPHERE DESTABILIZES. SITES THAT OBSERVE
CONVECTION WITHIN THEIR RESPECTED AERODROMES TODAY WILL LIKELY
EXPERIENCE A BRIEF BOUT OF MVFR/IFR FLIGHT STATUSES DUE TO DEGRADED
VISIBILITIES AND/OR CEILINGS. WIND GUSTS IN THE 26-34 KNOT RANGE
ARE ALSO POSSIBLE WITH THE MOST INTENSE STORMS. SUSTAINED WINDS
AWAY FROM CONVECTION TODAY WILL BE SOUTHEASTERLY BETWEEN 3-8 KNOTS.
SHOWERS AND STORMS WILL GRADUALLY DIMINISH THROUGH THE EVENING HOURS
AND VFR CONDITIONS WILL CONTINUE INTO THE NIGHT. WINDS WILL ALSO
SUBSIDE DURING THIS TIME...BECOMING LIGHT TO CALM OVERNIGHT INTO
MONDAY MORNING. PATCHY FOG AND LOW STRATUS WILL BE POSSIBLE
OVER MAINLY EAST AND SOUTHEAST MISSISSIPPI...KGTR...KMEI...AND
KHBG. THIS COULD AGAIN BRIEFLY REDUCE CEILINGS AND/OR VISIBILITIES
TO MVFR/IFR STATUS AROUND SUNRISE MONDAY. /19/
$$
.PREV DISCUSSION... /ISSUED 402 AM CDT SUN AUG 11 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT...SEASONAL WEATHER FOR MID
AUGUST WILL BE THE NAME OF THE GAME ACROSS THE ARKLAMISS THROUGH THE
FIRST PART OF THE WORK WEEK. THE "FLAT" UPPER RIDGE THATS BEEN IN
PLACE ACROSS THE SOUTHEASTERN CONUS WILL REMAIN THE MAIN STORY
THROUGH THE SHORT TERM. THE AIRMASS IS QUITE SOUPY AS PW VALUES HAVE
CLIMBED ABOVE 2 INCHES AND LOOK TO REMAIN IN EXCESS OF 2 IN FOR THE
NEXT FEW DAYS. MOSTLY CLEAR SKIES THIS MORNING WILL GIVE WAY TO
DECENT SHOWER AND THUNDERSTORM COVERAGE THIS AFTERNOON/EARLY EVENING
AS THE BOUNDARY LAYER HEATS UP. LATEST HRRR RUNS SUGGEST THE BEST
STORM COVERAGE EARLY ON WILL BE SOUTH OF THE NATCHEZ TRACE WITH
COVERAGE EXPANDING FURTHER NORTH AS TIME WEARS ON. LATEST LOCAL WRF
AND ASSOCIATED NAM GUIDANCE SUGGESTS BETTER COVERAGE ACROSS NORTHERN
ZONES EARLY ON BEFORE COVERAGE INCREASES ACROSS THE SOUTH IN THE
AFTERNOON AS THE SEA BREEZE WORKS ITS WAY IN. NEEDLESS TO SAY THERE
IS STILL SOME UNCERTAINTY IN THE DETAILS OF HOW TODAY WILL EVOLVE
ALTHOUGH I DO LIKE THE HRRR SOLUTION AT THIS POINT. LAPSE RATES LOOK
RATHER MEAGER ONCE AGAIN TODAY/SIMILAR TO YESTERDAY/AND WILL
HIGHLIGHT THE RISK OF A FEW STRONG STORMS IN THE HWO FOR THE
AFTERNOON...NOTHING TOO SIGNIFICANT. VERY WEAK FLOW IN THE
ATMOSPHERE WILL YIELD VERY SLOW STORM MOTIONS WHICH WILL ENHANCE THE
RISK FOR LOCALLY HEAVY RAINS AND FLOODING...WE`LL BE KEEPING AN EYE
ON THAT TODAY. A BLEND OF GFS MOS WITH THE COOLER NAM GUIDANCE GAVE
REASONABLE LOOKING HIGHS FOR TODAY IN THE LOW/MID 90S. ITS FEASIBLE
A FEW AREAS THAT SEE SOME CONVECTION EARLY ON AND HANG ON TO SOME
CLOUD COVER THROUGH THE DAY WILL STRUGGLE TO REACH 90.
CONVECTION WILL WANE THIS EVENING USHERING IN ANOTHER QUIET NIGHT
TONIGHT WITH LOWS FALLING INTO THE LOW/MID 70S. A REPEAT PERFORMANCE
OF TODAY LOOKS IN STORE FOR TOMORROW WITH CONVECTION EXPANDING IN
COVERAGE THROUGH THE AFTERNOON...BEFORE DIMINISHING DURING THE
EVENING. TEMPS WILL BE SIMILAR TO TODAY WITH HIGHS IN THE LOW/MID
90S/OVERNIGHT LOWS TUE MORNING IN THE LOW/MID 70S. /BK/
LONG TERM...TUESDAY THROUGH SUNDAY...THE GLOBAL MODELS CONTINUE TO
BE IN DECENT AGREEMENT AND SUPPORT THE PATTERN CHANGE THAT WILL
BRING WETTER AND COOLER CONDITIONS TO THE REGION.
AS WE HEAD INTO MID WEEK...THE FLAT MID/UPPER RIDGE WILL GIVE WAY TO
MORE OF A NW FLOW TYPE PATTERN. THIS WILL ALLOW A SFC FRONT TO
STEADILY MAKE ITS WAY INTO THE REGION BY THU. AHEAD OF THE FRONT
LOOK FOR AN ACTIVE CONVECTIVE REGIME TO DEVELOP AS DEEP LIFT AND LOW
LEVEL MOISTURE CONVERGENCE INCREASE. IT APPEARS THERE WILL BE
MULTIPLE OPPORTUNITIES FOR PRECIP BETWEEN TUE AND WED NIGHT WITH
SOME HEAVY RAINFALL POSSIBLE. A WIDESPREAD 1-2 INCHES IS LOOKING
LIKELY WITH LOCALIZED 2-4 POSSIBLE DURING THIS PERIOD. TIMING RAIN
EPISODES WILL BE TOUGH AS CHANCES WILL BE QUITE HIGH FOR EITHER DAY
OR NIGHT PERIODS. GFS POPS WERE PRETTY HIGH AND MOST OF THAT WAS
ACCEPTED. HOWEVER...ADJUSTMENTS WERE MADE BASED OFF EURO MODEL DATA
AND TIMING. AT THIS TIME (REMEMBER ITS STILL DAY 3-4) POPS WILL
RANGE FROM 50-70% DURING THE TUE-WED NIGHT PERIODS WITH THE SOME OF
THE BEST RAIN POTENTIAL FOCUSED ON WED. WHILE I MENTIONED THE MODELS
WERE IN DECENT AGREEMENT...THIS LATEST RUN OF THE GFS WAS A BIT
SLOWER AND THIS RESULTED IN SUBSTANTIALLY HIGH POPS FOR NORTHERN
SECTIONS OF THE AREA WED NIGHT. WHILE THERE IS UNCERTAINTY IN HOW
THE SYSTEM/PRECIP WILL EVOLVE...MORE WEIGHT WAS GIVEN TO THE TIMING
OF THE EURO DO TO ITS CONSISTENCY. AS A RESULT...POPS WERE LOWERED
LOWERED ACROSS THE NORTH TO FIT THE EURO TIMING AND STAY MORE IN
LINE WITH PREV FORECASTS.
BY THU...A MORE AMPLIFIED PATTERN WILL HELP PUSH THE SFC BOUNDARY
THROUGH THE CWA ALONG WITH THE DEEPER MOISTURE. AS A RESULT...PRECIP
POTENTIAL WILL BE ON THE DEGREASE. AGAIN...THE SLOWER GFS HELD ONTO
POPS MORE AND VALUES WERE TAPERED BACK TO MATCH MORE OF THE EURO.
GENERALLY DRIER CONDITIONS WILL EXIST FOR THE FRI-SUN PERIODS.
AS FOR TEMPS...COOLER READINGS ARE EXPECTED AND FOR THE MOST
PART...GUIDANCE IS SUPPORTING THIS. THE MAIN ISSUE IS ON TUE WHERE
THE GFS IS QUITE WARM. ENSEMBLE MOS ALONG WITH THE EURO AND NAM ARE
MUCH COOLER. THE COOLER SCENARIO FITS BETTER AS CLOUDS AND A EARLIER
START TO THE PRECIP ARE EXPECTED. DUE TO THIS...HIGH TEMPS WERE CUT
SOME 3-5 DEGREES. A SIMILAR SITUATION EXISTS ON WED. THE GFS IS
LOWER WITH TEMPS...BUT AGAIN IS THE WARM OUTLIER COMPARED TO THE
ENSEMBLE MOS AND EURO. WED COULD ACTUALLY BE SUBSTANTIALLY LOWER
THAN CLIMO WITH LOWER/MID 80S A REAL POSSIBILITY FOR HIGHS. WHILE I
DID NOT GET THAT AGGRESSIVE...TEMPS WERE CUT TO FIT A RANGE OF 86-89.
FOR THU-SUN...BELOW AVG CONDITIONS LOOK TO BE THE RULE AND THIS IS
SUPPORTED BY ALL EXTENDED MOS/MODEL DATA. /CME/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 91 72 91 73 / 53 30 55 28
MERIDIAN 91 71 90 72 / 58 30 54 38
VICKSBURG 91 73 92 71 / 50 30 49 24
HATTIESBURG 92 74 92 74 / 51 28 63 40
NATCHEZ 90 73 91 73 / 50 26 60 31
GREENVILLE 93 74 92 74 / 50 30 44 27
GREENWOOD 92 73 91 73 / 50 30 49 29
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
22/19/BK/CME
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
313 PM CDT Sun Aug 11 2013
.SHORT TERM: (Through Late Tonight)
Issued at 313 PM CDT Sun Aug 11 2013
Low level flow is turning back around to the south across southern
and central Missouri. Already seeing cumulus spread up to near
California Missouri and points west-northwest. A weak low level jet
develops tonight which produces some decent moisture convergence at
850mb primarily over southern portions of the CWFA. It doesn`t look
like the forcing is strong enough to produce very widespread or
organized convection, however the RUC is showing about 900 J/KG CAPE
in the region of moisture convergence, and the CAPE is fairly tall
extending up to 35,000ft. Certainly can`t rule out isolated-widely
scattered showers and thunderstorms over southeast Missouri and
possibly parts of east central and central Missouri as well, though
the lift drops off further north. Lows will be warmer tonight due
to the increasing cloud cover and southerly flow.
Carney
.LONG TERM: (Monday through Next Sunday)
Issued at 313 PM CDT Sun Aug 11 2013
Main concern continues to be thunderstorms chances early this week.
Scattered thunderstorms may be ongoing over the eastern Ozarks into
southern Illinois early Monday on the nose of a veering low level
jet. Better chance of storms will be focused along a cold front
that enters the northern CWFA early in the day and moves slowly
south through the day. Atmosphere will become increasingly
unstable along and ahead of the front with MLCAPEs around 1,000
J/kg with some weak CIN. This should be enough to generate
scattered thunderstorms given weak large scale ascent from a
passing shortwave. There may be a few strong storms that could
producing some gusty winds given the relatively dry low-mid levels
seen on the forecast soundings, though deep layer shear of only
25-30 knots will limit overall severe threat.
Not too many changes to previous thinking that rain chances will
diminish from north to south on Monday Night and Tuesday as the
front slowly moves south into the Mid South. Still have a dry
forecast going mid to late week as an impressive surface ridge
creeps southward through the area. Easterly low level flow and
850mb temperatures around 10C should keep temperatures below mid
August normals from Wednesday into Friday. Latest runs of the
GFS/ECMWF do agree that an upper trough will deepen over Missouri
and Illinois by Saturday. There will be Gulf moisture drawn
northward ahead of this trough, though any rain looks like it will
stay just south and east of us next weekend. 850mb temperatures
will warm into the mid-teens causing temperatures to climb closer
to normal by next weekend.
Britt
&&
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1236 PM CDT Sun Aug 11 2013
VFR flight conditions and light southeast flow will prevail for
the rest of the day into tonight across the region. There is a
small chance that some showers and possibly a thunderstorm could
develop across the eastern Ozarks before sunset. A weak low level
jet will develop late tonight over southern Missouri which may be
enough to develop isolated showers or thunderstorms along and
south of the I-70 corridor, but chances of precip appear to be
very low at this time so have left mention out of terminal
forecasts.
Specifics for KSTL:
VFR flight conditions and light southeast flow will continue to
prevail at Lambert through tonight. There is a slight chance that
some isolated showers or thunderstorms could develop south of the
terminal, around sunrise which could affect Lambert. However,
chances are so small right now that I`ve opted to leave mention of
precip out of the TAF at this time. A cold front will approach the
terminal from the north late Monday. Additional thunderstorm
development is possible ahead of the front Monday afternoon,
however am leaving mention out until we get a better handle on
timing and potential coverage of storms.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
852 PM MDT Mon Aug 12 2013
.UPDATE...
Increased pops and qpf across much of the eastern part of the zone
as showers and thunderstorms continue to move across central
Montana. The active weather pattern will continue through the
evening hours with some of the shower activity lasting well past
midnight. No significant changes to other parts of the forecast as
most of the impact tonight will be associated with the severe
thunderstorms. Suk
&&
.AVIATION...
UPDATED 2330Z.
Scattered moderate to strong thunderstorms currently occuring across
parts of central and southwest MT and also near/southwest of KCTB.
largest concentration of storms is in an area from KHLN to KLWT and
moving slowly east-northeast. Given that the generally unstable and
moist conditions around the region will continue into early-mid
evening, have included mention of thunder in all local TAFs through
02-03Z. Most significant threat from these storms will be very heavy
rain due to their observed/expected slow movement. Conditions will
remain VFR away from any storms, but MVFR visibilities possible for
short periods, but could last as long as an hour under the stronger
cells. Winds remaining light across the region this evening, except
for outflow gusts of 20-30 kts near any storms.
Waranauskas
&&
.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Aug 12 2013/
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Suk
LONG TERM...mpj
AVIATION...WARANAUSKAS
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
530 PM MDT Mon Aug 12 2013
AVIATION SECTION UPDATED
.DISCUSSION...
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.AVIATION...
UPDATED 2330Z.
Scattered moderate to strong thunderstorms currently occuring across
parts of central and southwest MT and also near/southwest of KCTB.
largest concentration of storms is in an area from KHLN to KLWT and
moving slowly east-northeast. Given that the generally unstable and
moist conditions around the region will continue into early-mid
evening, have included mention of thunder in all local TAFs through
02-03Z. Most significant threat from these storms will be very heavy
rain due to their observed/expected slow movement. Conditions will
remain VFR away from any storms, but MVFR visibilities possible for
short periods, but could last as long as an hour under the stronger
cells. Winds remaining light across the region this evening, except
for outflow gusts of 20-30 kts near any storms.
Waranauskas
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING until 8 PM MDT this evening Beaverhead...
Jefferson...Madison.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
958 AM MDT SUN AUG 11 2013
.UPDATE...
OVERALL FORECAST IN GOOD SHAPE. MAIN CHANGE WAS TO INCREASE POPS
THIS AFTERNOON IN RESPONSE TO NAM SHOWING A BETTER CHANCE OF
THUNDERSTORMS EARLY THIS AFTERNOON. NAM PICKED UP ON A WEAK VORT
CENTER DRIFTING OVER CENTRAL AREAS THIS MORNING HEADING INTO
SOUTHEAST MONTANA BY MID DAY. SATELLITE ALREADY SHOWING SOME MID
LEVEL CONVECTION WITH A FEW WEAK RADAR RETURNS OVER ROSEBUD
COUNTY. DO THINK THAT THIS ENERGY WILL GENERATE MORE CONVECTION
OVER NORTHEAST WYOMING THAN SOUTHEAST MONTANA BUT ENOUGH THERE TO
MENTION SLIGHT CHANCE OF STORMS. MAIN FOCUS THIS AFTERNOON WILL BE
A SHORTWAVE EMBEDDED IN DIFFLUENT SOUTHERLY FLOW MOVING INTO
SOUTHWEST/SOUTH CENTRAL MONTANA. MODELS IN GOOD AGREEMENT
DEVELOPING AN AREA OF CONVECTION OVER SOUTHWEST
MOUNTAINS...PUSHING NORTHEAST THROUGH THE LATE AFTERNOON AND
EVENING...SIMILAR TO LAST NIGHT. MOISTURE IS A BIT MORE LIMITED
TODAY OVER WESTERN ZONES SO THREAT FOR STRONG WIND GUSTS IS
GREATER THAN YESTERDAY. ONCE STORMS MOVE OFF THE MOUNTAINS AND
INTO THE LOWER ELEVATIONS MORE MOISTURE IS AVAILABLE FOR RAIN AND
SMALL HAIL. AS WAS THE CASE YESTERDAY THERE COULD BE A BRIEF
SEVERE STORM WITH LARGER HAIL DUE TO CELL MERGER/BOUNDARY
COLLISION...BUT OVERALL THE MAIN THREAT WILL BE GUSTY WINDS.
SREF/SSEO SOLUTIONS KEEP CONVECTION GOING OVER NORTHERN ZONES LATE
IN THE EVENING ACROSS NORTHERN ZONES...WITH A BIT OF AN ELEVATED
STRONG TO SEVERE THREAT AROUND MIDNIGHT OVER NORTHEAST ZONES. WILL
SEE IF THIS CONTINUES WITH LATEST MODEL RUNS AND MAY INCREASE
POPS AND MENTION STRONGER STORMS FOR THIS AREA WITH AFTERNOON
PACKAGE. TEMPERATURES LOOK PRETTY GOOD...BUT THERE IS AN AREA OF
DENSE SMOKE ALOFT MOVING OUT OF NORTH CENTRAL MONTANA TOWARD THE
SOUTHEAST. THIS COULD LIMIT HEATING BY A FEW DEGREES THIS
AFTERNOON CENTRAL AND EAST. CHAMBERS
&&
.SHORT TERM...VALID FOR TDY AND MON...
A BROAD 500-HPA RIDGE WILL KEEP A WARMING TREND GOING THE NEXT FEW
DAYS...BUT WEAK IMPULSES CUTTING THROUGH THE RIDGE WILL ALSO BRING
SOME CHANCES OF STORMS TO THE REGION AS WELL.
FIRST OF ALL...THE BOUNDARY LAYER IN SOUTHEASTERN MT IS VERY CLOSE
TO SATURATION AS OF 09 UTC...AND STRATUS IS BEGINNING TO FORM OVER
THE DAKOTAS AND AS FAR WEST AS BAKER. GIVEN WEAK EASTERLY GRADIENT
WINDS THROUGH THE MORNING...WE EXPECT STRATUS TO CONTINUE BUILDING
AND PROBABLY SET IN THROUGH AT LEAST LATE MORNING /A SCENARIO THAT
THE HRRR SUPPORTS/. WE WILL HAVE PATCHY FOG IN THE FORECAST ACROSS
SOUTHEASTERN MT THROUGH 15 UTC AS WELL. MEANWHILE...DRAINAGE WINDS
HAVE ACTUALLY TAKEN HOLD OVER SOUTH CENTRAL MT...WHICH HAS LOWERED
DEWPOINTS AND LIKELY NEGATED ANY FOG THREAT THIS MORNING IN PLACES
LIKE BILLINGS.
TODAY...WE HAVE REALIGNED AFTERNOON POPS TO FOCUS ON SOUTH CENTRAL
MT AND NORTH CENTRAL WY WHERE TERRAIN CIRCULATIONS WILL LIKELY AID
CONVECTIVE DEVELOPMENT...WHILE REMOVING THEM AND GOING WITHOUT ANY
MENTION OF STORM CHANCES IN MOST OF SOUTHEASTERN MT. THE CHOICE TO
GO WITH A DRY AFTERNOON FORECAST IN SOUTHEASTERN MT WAS BASED ON A
LACK OF DISCERNIBLE SHORT WAVE IMPULSES EITHER UPSTREAM IN MORNING
MOISTURE CHANNEL IMAGES OR IN AFTERNOON MODEL SIMULATIONS. NOT ONE
OF THE HIGH-RESOLUTION...CONVECTION-ALLOWING MODELS USED IN THE 00
UTC SPC SSEO DEVELOPED STORMS IN SOUTHEASTERN MT...WHICH CERTAINLY
HELPED BUILD OUR CONFIDENCE IN A DRY FORECAST. MLCAPE OF 1000 J/KG
WILL BE PRESENT DURING PEAK HEATING THOUGH...SO WE WILL KEEP WATCH
OF NEAR-TERM TRENDS IN CASE CHANCES NEED TO BE ADDED BACK IN LATER
ON. MEANWHILE...OVER SOUTH CENTRAL MT AND NORTH CENTRAL WY...AFTER
SEEING HOW EASILY CONVECTION FORMED SAT IN THIS SYNOPTIC SITUATION
OUR CONFIDENCE IN STORM DEVELOPMENT HAS INCREASED. THE MODELS FROM
00 UTC ADD SUPPORT FOR THIS. GUSTY WINDS OR EVEN A MARGINAL SEVERE
STORM IS POSSIBLE /SIMILAR TO SAT/. MOREOVER...THE 21 UTC SREF HAS
NOTABLE PROBABILITIES FOR DRY THUNDERSTORMS...WHICH IS A VERY REAL
POSSIBILITY WHERE FORECAST SOUNDINGS HAVE PRECIPITABLE WATERS LESS
THAN ABOUT 0.80 INCHES /WEST OF BILLINGS TOWARD LIVINGSTON/. BASED
ON MID- AND UPPER-LEVEL WINDS...STORM MOTIONS COULD BE SLOW ENOUGH
TO ELEVATE WETTING RAIN CHANCES A BIT MORE THAN THEY COULD BE IN A
SITUATION LIKE THIS...SO A LARGE-SCALE /RED FLAG-WORTHY/ LIGHTNING
EVENT IS NOT EXPECTED AT THIS TIME.
TONIGHT...THE 00 UTC SPC SSEO AS WELL AS 500-HPA VORTICITY MAXIMUM
FIELDS FROM THE 00 UTC GFS /AND TO AN EXTENT THE ECMWF/ SUPPORT 30
TO 40 PERCENT STORM CHANCES THIS EVENING FROM HARLOWTON TOWARD BIG
TIMBER AND EAST TO BILLINGS. GUSTY WINDS...MARGINAL SEVERE RISK...
AND SOME DRY LIGHTNING POTENTIAL WILL CONTINUE WITH STORMS THROUGH
THE EVENING AS WELL. LOW POPS ARE SUPPORTED OVER THE WHOLE AREA AS
A WEAK 500-HPA SHORT WAVE MAY MOVE INTO SOUTHEASTERN MT OVERNIGHT.
MON...THE LARGE-SCALE PATTERN WILL REMAIN SIMILAR...BUT THERE HAVE
BEEN SOME INDICATIONS FOR BETTER FORCING NEAR A STATIONARY FRONTAL
BOUNDARY IN SOUTHEASTERN MT DURING THE AFTERNOON AND EVENING. THAT
COULD GENERATE ANOTHER MORE NOTABLE SEVERE RISK GIVEN 0-6-KM SHEAR
VECTORS OF 30 KT OR MORE. WE NEED TO HAVE AT LEAST LOW POPS ACROSS
THE REST OF THE AREA AGAIN TOO. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
NO SIGNIFICANT CHANGES WERE MAE IN THE EXTENDED FORECAST PERIODS
FOR THIS PACKAGE. A RIDGE OF HIGH PRESSURE WILL DOMINATE THE
EXTENDED TIME FRAME WITH ACTIVE CONVECTIVE WEATHER THROUGH ABOUT
MIDWEEK...WINDING DOWN TO A DRIER AND WARMER REGIME FOR THE LATTER
PART OF THE WORK WEEK. LONG RANGE PROGGS DO INDICATE A SIGNIFICANT
WEATHER SYSTEM CRASHING THE RIDGE NEXT SATURDAY/SATURDAY NIGHT.
THIS WILL NEED TO BE MONITORED FOR FIRE WEATHER CONCERNS. BT
&&
.AVIATION...
AREAS OF FOG ARE LIFTING FROM KMLS TO KBHK AND SOUTH...BUT LOW
CLOUDS MAY LINGER INTO AFTERNOON. SHOWERS AND THUNDERSTORMS ARE
EXPECTED ACROSS ALL ROUTES THIS AFTERNOON AND INTO THE
EVENING...BEGINNING OVER WESTERN TERMINALS. LOCAL IFR TO MVFR CAN
BE EXPECTED WITHIN STRONGER THUNDERSTORMS. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 086 062/088 059/086 060/087 060/091 062/093 062/091
3/T 32/T 22/T 22/T 20/U 00/U 01/U
LVM 088 054/089 052/088 052/088 050/091 051/095 051/090
3/T 32/T 22/T 22/T 21/U 10/U 01/U
HDN 088 060/091 058/089 058/088 059/092 059/095 059/093
2/T 32/T 32/T 22/T 20/U 00/U 00/U
MLS 085 063/088 061/087 061/087 061/091 063/094 064/093
2/T 23/T 32/T 23/T 31/U 00/U 01/U
4BQ 085 059/088 058/086 058/087 058/090 059/093 059/093
2/T 23/T 32/T 33/T 30/U 00/U 00/U
BHK 080 058/082 056/080 057/082 057/087 058/089 059/089
2/T 23/T 33/T 33/T 32/T 00/U 01/U
SHR 087 056/088 055/087 056/087 054/089 055/092 055/092
3/T 33/T 32/T 22/T 21/U 10/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
319 AM MDT SUN AUG 11 2013
.SHORT TERM...VALID FOR TDY AND MON...
A BROAD 500-HPA RIDGE WILL KEEP A WARMING TREND GOING THE NEXT FEW
DAYS...BUT WEAK IMPULSES CUTTING THROUGH THE RIDGE WILL ALSO BRING
SOME CHANCES OF STORMS TO THE REGION AS WELL.
FIRST OF ALL...THE BOUNDARY LAYER IN SOUTHEASTERN MT IS VERY CLOSE
TO SATURATION AS OF 09 UTC...AND STRATUS IS BEGINNING TO FORM OVER
THE DAKOTAS AND AS FAR WEST AS BAKER. GIVEN WEAK EASTERLY GRADIENT
WINDS THROUGH THE MORNING...WE EXPECT STRATUS TO CONTINUE BUILDING
AND PROBABLY SET IN THROUGH AT LEAST LATE MORNING /A SCENARIO THAT
THE HRRR SUPPORTS/. WE WILL HAVE PATCHY FOG IN THE FORECAST ACROSS
SOUTHEASTERN MT THROUGH 15 UTC AS WELL. MEANWHILE...DRAINAGE WINDS
HAVE ACTUALLY TAKEN HOLD OVER SOUTH CENTRAL MT...WHICH HAS LOWERED
DEWPOINTS AND LIKELY NEGATED ANY FOG THREAT THIS MORNING IN PLACES
LIKE BILLINGS.
TODAY...WE HAVE REALIGNED AFTERNOON POPS TO FOCUS ON SOUTH CENTRAL
MT AND NORTH CENTRAL WY WHERE TERRAIN CIRCULATIONS WILL LIKELY AID
CONVECTIVE DEVELOPMENT...WHILE REMOVING THEM AND GOING WITHOUT ANY
MENTION OF STORM CHANCES IN MOST OF SOUTHEASTERN MT. THE CHOICE TO
GO WITH A DRY AFTERNOON FORECAST IN SOUTHEASTERN MT WAS BASED ON A
LACK OF DISCERNIBLE SHORT WAVE IMPULSES EITHER UPSTREAM IN MORNING
MOISTURE CHANNEL IMAGES OR IN AFTERNOON MODEL SIMULATIONS. NOT ONE
OF THE HIGH-RESOLUTION...CONVECTION-ALLOWING MODELS USED IN THE 00
UTC SPC SSEO DEVELOPED STORMS IN SOUTHEASTERN MT...WHICH CERTAINLY
HELPED BUILD OUR CONFIDENCE IN A DRY FORECAST. MLCAPE OF 1000 J/KG
WILL BE PRESENT DURING PEAK HEATING THOUGH...SO WE WILL KEEP WATCH
OF NEAR-TERM TRENDS IN CASE CHANCES NEED TO BE ADDED BACK IN LATER
ON. MEANWHILE...OVER SOUTH CENTRAL MT AND NORTH CENTRAL WY...AFTER
SEEING HOW EASILY CONVECTION FORMED SAT IN THIS SYNOPTIC SITUATION
OUR CONFIDENCE IN STORM DEVELOPMENT HAS INCREASED. THE MODELS FROM
00 UTC ADD SUPPORT FOR THIS. GUSTY WINDS OR EVEN A MARGINAL SEVERE
STORM IS POSSIBLE /SIMILAR TO SAT/. MOREOVER...THE 21 UTC SREF HAS
NOTABLE PROBABILITIES FOR DRY THUNDERSTORMS...WHICH IS A VERY REAL
POSSIBILITY WHERE FORECAST SOUNDINGS HAVE PRECIPITABLE WATERS LESS
THAN ABOUT 0.80 INCHES /WEST OF BILLINGS TOWARD LIVINGSTON/. BASED
ON MID- AND UPPER-LEVEL WINDS...STORM MOTIONS COULD BE SLOW ENOUGH
TO ELEVATE WETTING RAIN CHANCES A BIT MORE THAN THEY COULD BE IN A
SITUATION LIKE THIS...SO A LARGE-SCALE /RED FLAG-WORTHY/ LIGHTNING
EVENT IS NOT EXPECTED AT THIS TIME.
TONIGHT...THE 00 UTC SPC SSEO AS WELL AS 500-HPA VORTICITY MAXIMUM
FIELDS FROM THE 00 UTC GFS /AND TO AN EXTENT THE ECMWF/ SUPPORT 30
TO 40 PERCENT STORM CHANCES THIS EVENING FROM HARLOWTON TOWARD BIG
TIMBER AND EAST TO BILLINGS. GUSTY WINDS...MARGINAL SEVERE RISK...
AND SOME DRY LIGHTNING POTENTIAL WILL CONTINUE WITH STORMS THROUGH
THE EVENING AS WELL. LOW POPS ARE SUPPORTED OVER THE WHOLE AREA AS
A WEAK 500-HPA SHORT WAVE MAY MOVE INTO SOUTHEASTERN MT OVERNIGHT.
MON...THE LARGE-SCALE PATTERN WILL REMAIN SIMILAR...BUT THERE HAVE
BEEN SOME INDICATIONS FOR BETTER FORCING NEAR A STATIONARY FRONTAL
BOUNDARY IN SOUTHEASTERN MT DURING THE AFTERNOON AND EVENING. THAT
COULD GENERATE ANOTHER MORE NOTABLE SEVERE RISK GIVEN 0-6-KM SHEAR
VECTORS OF 30 KT OR MORE. WE NEED TO HAVE AT LEAST LOW POPS ACROSS
THE REST OF THE AREA AGAIN TOO. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
NO SIGNIFICANT CHANGES WERE MAE IN THE EXTENDED FORECAST PERIODS
FOR THIS PACKAGE. A RIDGE OF HIGH PRESSURE WILL DOMINATE THE
EXTENDED TIME FRAME WITH ACTIVE CONVECTIVE WEATHER THROUGH ABOUT
MIDWEEK...WINDING DOWN TO A DRIER AND WARMER REGIME FOR THE LATTER
PART OF THE WORK WEEK. LONG RANGE PROGGS DO INDICATE A SIGNIFICANT
WEATHER SYSTEM CRASHING THE RIDGE NEXT SATURDAY/SATURDAY NIGHT.
THIS WILL NEED TO BE MONITORED FOR FIRE WEATHER CONCERNS. BT
&&
.AVIATION...
A FEW LIGHT SHOWERS OR SPRINKLES WILL LINGER ACROSS THE FORECAST
AREA EARLY THIS MORNING...MAINLY ALONG AND NORTH OF A KLVM TO KBIL
AND KMLS LINE. AREAS OF FOG AND LOW CLOUDS ARE EXPECTED TO DEVELOP
BY SUNRISE AND LINGER THROUGH ABOUT 16Z FROM KMLS TO KBHK AND
SOUTHWARD. SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP ACROSS THE
AREA LATE THIS AFTERNOON AND INTO THE EVENING. LOCAL IFR TO MVFR
CAN BE EXPECTED WITHIN STRONGER THUNDERSTORMS. BT
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 088 062/088 059/086 060/087 060/091 062/093 062/091
2/T 32/T 22/T 22/T 20/U 00/U 01/U
LVM 090 054/089 052/088 052/088 050/091 051/095 051/090
3/T 32/T 22/T 22/T 21/U 10/U 01/U
HDN 089 060/091 058/089 058/088 059/092 059/095 059/093
2/T 22/T 32/T 22/T 20/U 00/U 00/U
MLS 087 063/088 061/087 061/087 061/091 063/094 064/093
1/B 23/T 32/T 23/T 31/U 00/U 01/U
4BQ 087 059/088 058/086 058/087 058/090 059/093 059/093
1/B 23/T 32/T 33/T 30/U 00/U 00/U
BHK 079 058/082 056/080 057/082 057/087 058/089 059/089
1/B 23/T 33/T 33/T 32/T 00/U 01/U
SHR 089 056/088 055/087 056/087 054/089 055/092 055/092
2/T 23/T 32/T 22/T 21/U 10/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
633 PM CDT MON AUG 12 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
THE MAIN ISSUES DURING THE NEXT 24 HOURS INCLUDE FICKLE
THUNDERSTORM CHANCES...ALONG WITH WHETHER OR NOT FOG TONIGHT MIGHT
END UP BEING IMPACTFUL IN SOME SPOTS.
20Z OBJECTIVE SURFACE ANALYSIS SHOWS A WEAK COLD FRONT STRETCHED
ACROSS KS FROM SOUTHWEST-NORTHEAST...WHILE TO THE NORTH OF THIS
BOUNDARY...THE MAJORITY OF THE CWA IS EXPERIENCING LIGHT BREEZES
RANGING FROM NEAR-CALM TO NO MORE THAN 5-10 MPH FROM THE EAST-
NORTHEAST UNDER THE INFLUENCE OF BROAD HIGH PRESSURE EXTENDING
WELL SOUTHWARD FROM CANADA. ALOFT...WATER VAPOR IMAGERY AND SHORT
TERM MODEL DATA SHOWS GENERALLY WEST-NORTHWEST FLOW ALOFT OVER THE
CENTRAL PLAINS...MORE WESTERLY UP AROUND 300 MILLIBARS..AND MORE
NORTHERLY FARTHER DOWN IN THE MID LEVELS 500/700 MILLIBARS. THIS
FLOW REGIME REMAINS ESTABLISHED BETWEEN A LARGE SCALE TROUGH OVER
THE GREAT LAKES/SOUTHEAST CANADA AREA...AND A RIDGE EXTENDING
NORTH-NORTHWEST INTO THE ROCKIES OUT OF THE TX/NORTHERN MEXICO
AREA. IN TERMS OF THE REGIONAL SCALE...THE MAIN LOW AMPLITUDE
DISTURBANCE OF INTEREST HAS PASSED ONTO THE EAST INTO
MO...ALTHOUGH SMALL RIBBONS OF CHANNELED VORTICITY ARE EVIDENT
EXTENDING BACK WEST-NORTHWEST ACROSS THE SOUTHERN CWA TOWARD THE
WY/NE/CO BORDER AREA PER LATEST OBJECTIVE MESO-ANALYSIS.
DESPITE WHAT VARIOUS MODELS WERE EARLIER-SHOWING...THE CWA HAS
REMAINED DRY ALL DAY IN THE WAKE OF THE EXTENSIVE CONVECTION
SUNDAY EVENING/EARLY THIS MORNING. VISIBLE SATELLITE REVEALS ONLY
A SCATTERED TO LOCALLY BROKEN FAIR WEATHER CUMULUS FIELD MAINLY IN
THE FAR NORTHERN/EASTERN/SOUTHERN COUNTIES...AND HIGH TEMPERATURES
ARE ON TRACK TO TOP OUT 82-85 NEARLY ALL AREAS.
FOR LATE THIS AFTERNOON INTO THIS EVENING...MODELS CONTINUE TO
STRUGGLE WITH THEIR INDIVIDUAL QPF FIELDS...AS SOME APPEAR TO
THINK THAT CONVECTION WILL BREACH A WEAK CAP LOCALLY. LEANING
TOWARD THE HIGHER-RES SOLUTIONS OF THE HRRR AND 4KM WRF
NMM/ARW...IT APPEARS RATHER UNLIKELY THAT ANYTHING WILL POP IN THE
NEXT 3-6 HOURS ESPECIALLY ACROSS THE CENTRAL/EASTERN CWA DUE TO
LACK OF FORCING AND LACK OF LOW-LEVEL CONVERGENCE...AS THE WEAK
CAP SHOULD HOLD DESPITE THE PRESENCE OF 1000-1500 J/KG 0-1KM MIXED
LAYER CAPE PER LATEST RUC ANALYSIS. AS A RESULT...THROUGH MIDNIGHT
HAVE CONFINED SLIGHT POPS TO MAINLY THE WESTERN 1/4 TO 1/3 OF THE
CWA...MAINLY TO ACCOUNT FOR THE SMALL POSSIBILITY THAT STORMS
CURRENTLY DEVELOPING IN WESTERN NEB...AND MAYBE EVENTUALLY IN
NORTHWEST KS AS WELL...MIGHT SLIP EASTWARD INTO THE CWA. GIVEN THE
CONTINUED WEAK DEEP LAYER SHEAR REGIME ONLY AROUND 20KT...AND
INSTABILITY FADING WITH TIME TONIGHT...THINK THE PROBABILITY OF
STRONG THUNDERSTORMS...LET ALONE SEVERE...IS QUITE LOW. AFTER
MIDNIGHT...UNCERTAINTY CONTINUES TO GROW...BUT WITH BOTH THE
LATEST HRRR AND 18Z NAM ADVERTISING SOME CONVECTION FLARING UP
MAINLY JUST NORTHWEST OF THE CWA LIKELY IN RESPONSE TO SOME SUBTLE
MID LEVEL THETA-E ADVECTION...AND OTHER MODELS SHOWING CONVECTION
LURKING IN OR NEAR KS ZONES...WENT AHEAD AND EXPANDED 20-30 POPS
TO INCLUDE ALL BUT A HANDFUL OF SOUTHEASTERN COUNTIES JUST IN
CASE. THE OTHER POTENTIAL ISSUE TONIGHT IS FOG. WHILE MET/MAV
GUIDANCE IS SUGGESTING ONLY SOME LIGHT FOG...THE 15Z SREF SUGGESTS
PERHAPS AN ENHANCED RISK OF VISIBILITY RESTRICTIONS BELOW 1 MILE
ESPECIALLY ACROSS THE SOUTHWEST 1/3 OF THE CWA LATE TONIGHT.
CERTAINLY THE VERY LIGHT EASTERLY FLOW REGIME AND RECENT RAINFALL
COULD HELP THE CAUSE OF FOG FORMATION...BUT GIVEN THAT FOG DID NOT
BECOME TOO MUCH OF AN ISSUE LAST NIGHT IN THE WAKE OF DEPARTING
CONVECTION WITH A SIMILAR WIND REGIME...DECIDED TO ONLY INTRODUCE
A PATCHY FOG MENTION CWA-WIDE FOR NOW LATE TONIGHT...AND DEFER TO
NEXT FEW SHIFTS TO MONITOR THE SITUATION AND RAMP UP FOG POTENTIAL
IF NECESSARY.
TURNING TO THE TUESDAY DAYTIME HOURS...THE QUESTIONS JUST CONTINUE
TO ARISE. TAKING VARIOUS MODEL QPF FIELDS AT FACE VALUE...THERE
COULD BE QUITE A BIT OF ONGOING CONVECTION DURING THE
DAY...ESPECIALLY ACROSS THE WESTERN HALF OF THE CWA...POSSIBLY AS
A CONTINUATION OF OVERNIGHT ACTIVITY MOVING IN...OR LOCAL
DEVELOPMENT RAMPING UP WITH DAYTIME HEATING...AS THE THERMODYNAMIC
STRUCTURE OF THE ATMOSPHERE SHOULD REMAIN SIMILAR TO TODAY WITH
WEAK CAPPING IN THE PRESENCE OF ROUGHLY 1000 J/KG OF CAPE. THE
MILLION DOLLAR QUESTION IS WHETHER NOT FORCING WILL BE STRONG
ENOUGH TO REALIZE THE POTENTIALLY WIDESPREAD CONVECTION ADVERTISED
BY SOME MODELS...OR WHETHER MODELS ARE OVER-DOING QPF AS SEVERAL
DID FOR TODAY. THERE SHOULD AT LEAST BE A FEW SUBTLE SHORTWAVE
TROUGHS PASSING THROUGH THE REGION PER MODEL VORTICITY
FIELDS...PRIMARILY PASSING ACROSS THE SOUTHWEST 1/2 OF THE CWA AND
POINT SOUTH. FOR NOW...DECIDED TO MAKE LITTLE CHANGE TO PREVIOUS
FORECAST WHICH ALREADY HAD POPS LOW AT NO MORE THAN 20-30
PERCENT...WITH THESE CHANCES COVERING MOST OF THE CWA IN THE
MORNING...AND THE ENTIRE AREA IN THE AFTERNOON. IF FORCING IS IN
FACT ENOUGH TO GENERATE WIDESPREAD CONVECTION...THEN NEXT SHIFT
MAY HAVE TO RAISE POPS NOTICEABLY ESPECIALLY IN WESTERN
AREAS...BUT AFTER SEEING HOW TODAY ENDED UP BONE-DRY THROUGH LATE
AFTERNOON...THINK IT WOULD BE UNWISE TO GET CARRIED AWAY WITH RAIN
CHANCES EVEN 12-24 HOURS OUT. AGAIN...NOT EXPECTING ANY SEVERE
STORMS...BUT A LOCALIZED STRONG STORM PROBABLY NOT OUT OF THE
QUESTION. OBVIOUSLY HIGH TEMPERATURES WILL BE HIGHLY DEPENDENT ON
THE COVERAGE...OR LACK THEREOF...OF DAYTIME CONVECTION...SO THERE
IS SOME UNCERTAINTY HERE TOO. GIVEN A SIMILAR LOW-LEVEL TEMP
REGIME...BLENDED THE COOLER PREVIOUS FORECAST FOR TOMORROW WITH
READINGS SIMILAR TO THOSE OBSERVED TODAY...WHICH RESULTS IN A
SLIGHT INCREASE TO PREVIOUS HIGHS AND NOW CALLING FOR 79-82 MOST
AREAS. BREEZES DURING THE DAY SHOULD AVERAGE ONLY 5-10 MPH FROM
THE EAST ASSUMING CONVECTIVE OUTFLOW DOESN/T GET TOO INVOLVED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
HE COOLER THAN NORMAL TREND WILL LIKELY CONTINUE THROUGH AT LEAST
SATURDAY...WITH PERHAPS A RETURN OF NEAR NORMAL HIGHS BY SUNDAY AND
MONDAY. WEAK SHORT WAVES WILL TRACK ACROSS OUR FORECAST AREA WITHIN
THE PERSISTENT UPPER LEVEL NORTHWESTERLY FLOW REGIME.
CONSEQUENTLY...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE ACROSS AT LEAST PORTIONS OF OUR FORECAST AREA OFF AND ON
AGAIN THROUGH MUCH OF THE PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY...A DECENT 500 MB VORT MAX/SHORT
WAVE WILL TRACK SOUTHEAST ACROSS THE HIGH PLAINS BRINGING A CHANCE
OF THUNDERSTORMS PRIMARILY TO AREAS WEST OF OUR FORECAST AREA.
HOWEVER...THERE IS GENERALLY A SLIGHT CHANCE THAT A FEW OF THESE
THUNDERSTORMS COULD TRACK INTO OUR WESTERN ZONES PRIMARILY WEST OF
HWY 281. INSTABILITY AND SHEAR ARE BOTH WEAK AND THUS ANY
THUNDERSTORMS THAT WORK INTO OUR AREA WILL LIKELY BE NON SEVERE.
TEMPERATURES WILL BE COOL FOR THIS TIME OF YEAR WITH THE UPPER LEVEL
JET STREAM TO OUR SOUTH.
WEDNESDAY NIGHT THROUGH FRIDAY...THIS SHOULD BE OUR BEST CHANCE AT
MORE WIDESPREAD THUNDERSTORM POTENTIAL ACROSS THE FORECAST AREA AS
A TRAIN OF SUCCESSIVE SHORT WAVE TROUGHS WORK THEIR WAY ACROSS THE
CENTRAL PLAINS. UPPER LEVEL SHEAR AND INSTABILITY WILL ALSO BE ON
THE INCREASE ESPECIALLY THURSDAY AFTERNOON THROUGH FRIDAY...WHICH
MAY RESULT IN A FEW STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. AT
THIS POINT...IT DOES NOT APPEAR TO BE A WIDESPREAD SEVERE
EVENT...BUT CAN NOT RULE OUT THE POSSIBILITY OF ISOLATED SEVERE
STORMS. TEMPERATURES WILL REMAIN RELATIVELY COOL...UPPER 70S TO
AROUND 80 DUE TO CLOUDS...POTENTIAL PRECIPITATION...AND MEAN MID
AND UPPER LEVEL JET POSITION.
SATURDAY AND SUNDAY...A BIT OF AN UPPER RIDGE IS PREDICTED TO WORK
INTO OUR FORECAST AREA THAT IF IT VERIFIES WOULD RESULT IN DRY
CONDITIONS THIS WEEKEND AND THEN WARMING TEMPERATURES TO NEAR NORMAL
BY SUNDAY.
SUNDAY NIGHT AND MONDAY...THE NEXT UPPER SHORT WAVE IS PROJECTED BY
BOTH THE 12Z GFS AND 12Z ECMWF TO MOVE INTO THE CENTRAL PLAINS. THIS
WILL RESULT IN AT LEAST SOME CHANCE OF THUNDERSTORMS...PARTICULARLY
ACROSS OUR WEST...ALTHOUGH THESE CHANCES MAY EVENTUALLY NEED TO BE
EXPANDED/RAISED SHOULD CURRENT FAVORABLE MODEL TRENDS CONTINUE.
ALLBLEND GIVES US NEAR NORMAL TEMPERATURES...AND LIKELIHOOD IS THAT
WE WILL LIKELY BE NO WARMER THAN NORMAL...AND WOULD NOT BE SURPRISED
IF MONDAY HIGHS GET LOWERED SOME WITH FUTURE FORECAST UPDATES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 614 PM CDT MON AUG 12 2013
VFR CONDITIONS FORECAST THROUGH THROUGH 10Z...MVFR 10-14Z...AND
THEN VFR 14Z ONWARD.
LOW AND HIGH LEVEL CLOUDS WILL BOTH BE POSSIBLE DURING THE TAF
PERIOD. AT THIS TIME HOWEVER CEILINGS ARE NOT EXPECTED TO DROP
BELOW 4000FT AGL. GUIDANCE SUGGESTS MVFR VISIBILITY WILL BE
POSSIBLE IN FOG TOWARDS SUNRISE TUESDAY AND AS A RESULT...WENT
AHEAD WITH MVFR CONDITIONS 10-14Z. THE SURFACE WIND WILL REMAIN
LIGHT AND VARIABLE...BUT WILL BECOME MORE ESTABLISHED FROM THE
SOUTHEAST DURING THE DAY TUESDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
308 PM CDT SUN AUG 11 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 245 PM CDT SUN AUG 11 2013
A SURFACE TROUGH OF LOW PRESSURE ACROSS NORTHERN NEBRASKA THIS
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH CONVERGENCE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE OUTLOOK
AREA BY LATE AFTERNOON AS THE CAP BEGINS TO WEAKEN. WHILE THE
INSTABILITY VALUES REMAIN HIGH...ON THE ORDER OF 3000 J/KG OF MU
CAPE...THE WIND SHEAR VALUES ARE VERY WEAK...AND PRIMARY CONCERN
WITH THESE STORMS WILL BE THE POTENTIAL FOR LARGE HAIL. MODELED
SOUNDINGS ALSO INDICATE AN INVERTED V ATMOSPHERIC PROFILE FOR THE
LATE AFTERNOON AND EARLY EVENING HOURS...SO STRONG WIND GUSTS MAY
ALSO BE A CONCERN. NOT SURPRISINGLY...THE ENTIRE OUTLOOK ARE
REMAINS IN A SLIGHT RISK FOR SEVERE WEATHER FROM SPC...WITH LARGE
HAIL AND WINDS BEING THE PRIMARY CONCERN.
SOME OF THE LATEST MODEL RUNS ARE INDICATING THE CONVECTION
CURRENTLY DEVELOPING ACROSS THE HIGH PLAINS AND ASSOCIATED WITH A
PASSING SHORTWAVE IN WV IMAGERY...WILL EVENTUALLY MERGE WITH
CONVECTION IN PROXIMITY OF THE SURFACE TROUGH...WHICH COULD RESULT
IN AN ACTIVE EVENING...PRECIPITATION WISE...ACROSS THE LOCAL
AREA. THE 12Z WRF APPEARS TO BE THE MOST AGGRESSIVE WITH THE
SCENARIO...AND THE 18Z RAP ALSO HINTING AT A SOLUTION SIMILAR TO
THIS...SO FELT CONFIDENT ENOUGH TO INCREASE POPS THROUGH THE EARLY
EVENING HOURS INTO THE 50 PERCENT RANGE ACROSS MOST OF THE AREA.
OTHERWISE...WITH THE SLOW MOVEMENT OF ANY STORMS THAT DO
DEVELOP...HEAVY RAINFALL WILL ALSO BE A CONCERN...AND CONTINUED
WITH THE POTENTIAL FOR VERY LOCALIZED FLOODING THIS EVENING AND
OVERNIGHT.
FOR MONDAY...EXPECT A MOSTLY DRY START TO THE DAY...WITH
INCREASING CHANCES FOR PRECIPITATION BY AFTERNOON AS WE COULD SEE
SOME CONVECTION REDEVELOP IN THE VICINITY OF THE STALLED OUT
FRONT/TROUGH WHICH WILL THEN BE ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 245 PM CDT SUN AUG 11 2013
COOLER THAN NORMAL SUMMER WEATHER WILL SETTLE IN ACROSS OUR REGION
FOR MUCH OF THE WORKWEEK IN A NORTHWEST FLOW REGIME ACROSS THE
CENTRAL PLAINS. WARMER AIR WILL RESIDE TO THE WEST FM THE DESERT SW
NORTH ACROSS THE ROCKIES...WHILE TO THE EAST...A TROUGH NEAR THE
HUDSON BAY WILL DEEPEN AND TRANSLATE ACROSS THE EASTERN CONUS.
COOLER AIR WILL BACK IN ACROSS THE PLAINS FM THE UPPER MIDWEST AND A
1022ISH MB SFC HIGH WILL BUILD SOUTH FM THIS AREA ONTO THE PLAINS...AND
WILL REINFORCE THE COOLER AIRMASS UNTIL AROUND THE THURSDAY TIME
FRAME. BY THE END OF THE WEEK AND HEADING INTO THE WEEKEND...THE
SFC RIDGE AXIS SLIDES EAST AND THE UPPER RIDGE OVER THE ROCKIES WILL
BEGINS TO BUILD TOWARDS THE PLAINS AND TEMPERATURES WILL BEGIN TO
MODERATE CLOSER TO SEASONAL NORMALS.
FOR CONVECTIVE POTENTIAL...CANNOT RULE OUT TSTM CHANCES DURING THIS
TIME FRAME...WITH DEVELOPMENT DEPENDENT UPON BOUNDARY LOCATIONS AND
TIMING OF WAVES. ON MONDAY...A FEW STORMS MAY LINGER IN THE
MORNING...WITH REDEVELOPMENT POSSIBLE DURING THE DAY ALONG A BACK
DOOR COOL FRONTAL BOUNDARY AND ALSO TO THE WEST IN AN UPSLOPE FLOW
REGIME. A STRONG TO SEVERE STORM IS POSSIBLE IN SUFFICIENT
INSTABILITY...BUT SHEAR REMAINS WEAK. THE BETTER PCPN CHCS BEGIN TO
FOCUS TO OUR WEST THROUGH MID WEEK...WITH SOME POTENTIAL FOR HIGH
PLAINS CONVECTION TO MIGRATE EAST TOWARDS OUR WESTERN CWA. AS
PATTERN CONTINUES TO AMPLIFY...FOCUS TURNS MORE TO TIMING OF WAVES
TOPPING RIDGE AND CROSSING THE PLAINS...WITH HIT OR MISS CHCS FOR
THE OUTER PERIODS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE
POPS.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1230 PM CDT SUN AUG 11 2013
VFR CONDITIONS WILL PREVAIL AT KGRI FOR THE NEXT SEVERAL HOURS AS
VARIABLY CLOUDY SKIES STREAM ACROSS THE REGION. GUSTY SOUTHERLY
WINDS WILL ALSO CONTINUE THROUGH ABOUT 23Z...WHEN THE SURFACE
TROUGH ACROSS NORTHERN NEBRASKA SAGS CLOSER TO THE TERMINAL. THIS
TROUGH SHOULD PROVIDE ENOUGH CONVERGENCE FOR THE DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE EVENING HOURS...AND
INTRODUCED A TEMPO GROUP FOR MVFR VSBYS AND CIGS FROM
11/23Z-12/02Z...AS THIS BOUNDARY SAGS SOUTH. OTHERWISE...WINDS
WILL BE LIGHT AND VARIABLE TOWARDS MORNING...WITH VFR CONDITIONS
AND LIGHT NORTHEASTERLY WINDS EXPECTED DURING THE DAY MONDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...FAY
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1206 PM CDT SUN AUG 11 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
POTENTIAL FOR TSRA THROUGH THE EVENING AND POTENTIAL FOR IFR
CONDITIONS LATER TONIGHT ARE THE MAIN AVIATION CONCERNS. EXPECT
SCATTERED STORMS TO DEVELOP ACROSS EASTERN NEBRASKA THIS AFTN
AND CONTINUE THIS EVENING. UNCERTAINTY EXITS AS TO HOW LONG STORMS
WILL BE AROUND BUT COVERAGE SHOULD DECREASE SOME BY AROUND SUNSET.
WINDS WILL SHIFT TO THE NORTH INITIALLY THEN BECOME NORTHEAST.
SHALLOW COOL MOIST AIRMASS BEHIND THE FRONT WILL BE FAVORABLE FOR
SOME FOG AND LOW CLOUDS. DID MENTION IFR CEILINGS AND VSBYS AT
KOFK...AND WILL NEED TO MONITOR FOR POSSIBLE INCLUSION FOR KOMA
AND KLNK.
MILLER
&&
.PREV DISCUSSION... /ISSUED 246 AM CDT SUN AUG 11 2013/
DISCUSSION...
PRECIPITATION CHANCES THROUGH MONDAY NIGHT PRIMARY FORECAST FOCUS
AS A WEAK FRONT SAGS ACROSS THE FA LATE TODAY INTO MONDAY.
EARLY MORNING SATELLITE/RADAR SHOWED A VORT MAX/TROUGH MOVG SE
ACROSS NWRN MN WITH SEVERAL CONVECTIVE CLUSTERS TO THE SW ON NOSE
OF LOW LEVEL JET/WARM ADVECTION OVR SD INTO NW IA. ALTHOUGH
VARIOUS SHORT TERM MODELS LIKE HOP WRF/RAP KEPT PRECIP MOSTLY NE
OF FA THIS AM ...4KM WRF AND HRRR DID TRY TO DEVELOP SOME OVER NRN
ZONES THIS MORNING. SO SOME SMALL POPS WILL BE MAINTAINED WITH
LAST MINUTE ADJUSTMENTS POSSIBLE BASED ON TRENDS BEFORE ISSUANCE.
OTHERWISE WITH BOUNDARY FORECAST TO SLOWLY SAG INTO NRN ZONES THIS
AFTN...HEATING SHOULD HELP REGENERATE CONVECTION LATER THIS
AFTERNOON...ALTHOUGH 4KM WHICH DEVELOPED IT MOSTLY S OF HIGHWAY 30
APPEARED TOO FAR S. COVERAGE THIS AFTERNOON AND EVOLUTION TONIGHT
IN DOUBT AS H5-H7 QG FORCING WAS NEGLIGIBLE WITH DIFFERENTIAL
HEATING ACROSS BOUNDARY THIS AFTN THEN SYSTEM MOTION FOR INFLOW
WOULD BE PRIMARY DRIVERS AS LOW LEVEL JET WEAKENS FAIRLY
SUBSTANTIALLY THROUGH TONIGHT. THUS KEPT POPS IN CHC CATEGORY FOR
NOW FOR LATE AFTN THROUGH EARLY TONIGHT. WITH THIS LACK OF LOW
LEVEL JET TONIGHT CONFIDENCE NOT VERY HIGH ON HOW MUCH COVERAGE
WILL EXIST AFTER 06Z OVER FA SO GENERALLY TRENDED POPS DOWN AFTER
THAT TIME. WITH MODEL AGREEMENT IN H85 THERMAL RIDGE POKING UP
TOWARD WCNTRL ZONES THIS AFTN BOOSTED HIGHS A BIT...WHICH WERE
STILL BELOW WARMER NAM WHICH ONE OF THESE DAYS MAY ACTUALLY TURN
OUT BETTER IF SWRLY SFC WINDS CAN BE MAINTAINED LONG ENOUGH.
IF CONVECTION TONIGHT PUSHES EFFECTIVE BOUNDARY SOUTH OF FA BY
MONDAY AFTN FURTHER CONVECTIVE DEVELOPMENT COULD BE LIMITED OVER
OUR AREA AND TRENDS WILL NEED MONITORING. HOWEVER...FOR NOW LEFT
IN CHC POPS S WITH SLIGHTS N THROUGH NORFOLK OR SO AS BOUNDARY
PUSH WAS MODEST AT BEST. ALTHOUGH H85 TEMPS DON/T COOL SIGNIFICANTLY
YET ON MONDAY...TEMPERATURES SHOULD BE SOMEWHAT COOLER MOST
AREAS...ESPECIALLY IF DEBRIS CLOUDS CAN BE MAINTAINED. SOME POPS
WERE KEPT THEN MONDAY NIGHT SW 2/3RDS OR SO IN CASE ANY UPSTREAM
CONVECTION WOULD HOLD TOGETHER...ALTHOUGH MUST SAY NOT REALLY SOLD
ON THAT IDEA.
IN FACT...EVEN THOUGH SOME SMALL POPS WERE ALSO MAINTAINED TO INTO
MIDWEEK BEFORE SPREADING E TOWARD FRIDAY...APPEARS BULK OF ANY
ACTIVITY COULD REMAIN TO OUR WEST THROUGH LATE WEEK...ESPECIALLY
PER 00Z ECMWF. THAT MODEL HAS REMAINED FAIRLY CONSISTENT IN THAT
REGARD. PLEASANT TEMPERATURES LOOK IN STORE FOR FORECAST AREA
MUCH OF NEXT WEEK BEFORE MODERATING LATE AS NORTHWESTERLY FLOW
SENDS CANADIAN HIGH PRESSURE DOWN MISSISSIPPI VALLEY. THIS HAS
BEEN ONE OF OUR SAVING GRACES THIS SUMMER AS SIGNIFICANTS RAINS
HAVE BEEN SPOTTY AND MANY AREAS ARE RUNNING MODERATE PRECIP
DEFICITS SINCE JUNE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
638 AM CDT SUN AUG 11 2013
.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK.
MAIN AVN CONCERN IS TSRA DEVELOPING LATER THIS AFTN. A FRONTAL
BNDRY OVER THE DAKOTAS THIS MORNING IS EXPECTED TO SLOWLY DRIFT
SWD AND PUSH INTO ERN NEBR LATE THIS AFTN. EXPECT STORMS WILL
DEVELOP ROUGHLY BTWN KSUX AND KGRI THEN ADVANCE SWD INTO THE
EARLY EVENING. ENVIRONMENTAL CONDITIONS WILL BE FAVORABLE FOR A
FEW SVR TSRA...AND AT THIS POINT PROBABLY MORE LIKELY TO BE AN
ISSUE AT KOMA AND KLNK. HOWEVER...WENT CONSERVATIVE WITH THE 12Z
TAF GROUPS AND DID NOT INCLUDE MENTION OF SVR STORMS IN THE TEMPO
GROUPS. OTHERWISE VFR THE REST OF THE FCST PD.
DEE
&&
.PREV DISCUSSION... /ISSUED 246 AM CDT SUN AUG 11 2013/
DISCUSSION...
PRECIPITATION CHANCES THROUGH MONDAY NIGHT PRIMARY FORECAST FOCUS
AS A WEAK FRONT SAGS ACROSS THE FA LATE TODAY INTO MONDAY.
EARLY MORNING SATELLITE/RADAR SHOWED A VORT MAX/TROUGH MOVG SE
ACROSS NWRN MN WITH SEVERAL CONVECTIVE CLUSTERS TO THE SW ON NOSE
OF LOW LEVEL JET/WARM ADVECTION OVR SD INTO NW IA. ALTHOUGH
VARIOUS SHORT TERM MODELS LIKE HOP WRF/RAP KEPT PRECIP MOSTLY NE
OF FA THIS AM ...4KM WRF AND HRRR DID TRY TO DEVELOP SOME OVER NRN
ZONES THIS MORNING. SO SOME SMALL POPS WILL BE MAINTAINED WITH
LAST MINUTE ADJUSTMENTS POSSIBLE BASED ON TRENDS BEFORE ISSUANCE.
OTHERWISE WITH BOUNDARY FORECAST TO SLOWLY SAG INTO NRN ZONES THIS
AFTN...HEATING SHOULD HELP REGENERATE CONVECTION LATER THIS
AFTERNOON...ALTHOUGH 4KM WHICH DEVELOPED IT MOSTLY S OF HIGHWAY 30
APPEARED TOO FAR S. COVERAGE THIS AFTERNOON AND EVOLUTION TONIGHT
IN DOUBT AS H5-H7 QG FORCING WAS NEGLIGIBLE WITH DIFFERENTIAL
HEATING ACROSS BOUNDARY THIS AFTN THEN SYSTEM MOTION FOR INFLOW
WOULD BE PRIMARY DRIVERS AS LOW LEVEL JET WEAKENS FAIRLY
SUBSTANTIALLY THROUGH TONIGHT. THUS KEPT POPS IN CHC CATEGORY FOR
NOW FOR LATE AFTN THROUGH EARLY TONIGHT. WITH THIS LACK OF LOW
LEVEL JET TONIGHT CONFIDENCE NOT VERY HIGH ON HOW MUCH COVERAGE
WILL EXIST AFTER 06Z OVER FA SO GENERALLY TRENDED POPS DOWN AFTER
THAT TIME. WITH MODEL AGREEMENT IN H85 THERMAL RIDGE POKING UP
TOWARD WCNTRL ZONES THIS AFTN BOOSTED HIGHS A BIT...WHICH WERE
STILL BELOW WARMER NAM WHICH ONE OF THESE DAYS MAY ACTUALLY TURN
OUT BETTER IF SWRLY SFC WINDS CAN BE MAINTAINED LONG ENOUGH.
IF CONVECTION TONIGHT PUSHES EFFECTIVE BOUNDARY SOUTH OF FA BY
MONDAY AFTN FURTHER CONVECTIVE DEVELOPMENT COULD BE LIMITED OVER
OUR AREA AND TRENDS WILL NEED MONITORING. HOWEVER...FOR NOW LEFT
IN CHC POPS S WITH SLIGHTS N THROUGH NORFOLK OR SO AS BOUNDARY
PUSH WAS MODEST AT BEST. ALTHOUGH H85 TEMPS DON/T COOL SIGNIFICANTLY
YET ON MONDAY...TEMPERATURES SHOULD BE SOMEWHAT COOLER MOST
AREAS...ESPECIALLY IF DEBRIS CLOUDS CAN BE MAINTAINED. SOME POPS
WERE KEPT THEN MONDAY NIGHT SW 2/3RDS OR SO IN CASE ANY UPSTREAM
CONVECTION WOULD HOLD TOGETHER...ALTHOUGH MUST SAY NOT REALLY SOLD
ON THAT IDEA.
IN FACT...EVEN THOUGH SOME SMALL POPS WERE ALSO MAINTAINED TO INTO
MIDWEEK BEFORE SPREADING E TOWARD FRIDAY...APPEARS BULK OF ANY
ACTIVITY COULD REMAIN TO OUR WEST THROUGH LATE WEEK...ESPECIALLY
PER 00Z ECMWF. THAT MODEL HAS REMAINED FAIRLY CONSISTENT IN THAT
REGARD. PLEASANT TEMPERATURES LOOK IN STORE FOR FORECAST AREA
MUCH OF NEXT WEEK BEFORE MODERATING LATE AS NORTHWESTERLY FLOW
SENDS CANADIAN HIGH PRESSURE DOWN MISSISSIPPI VALLEY. THIS HAS
BEEN ONE OF OUR SAVING GRACES THIS SUMMER AS SIGNIFICANTS RAINS
HAVE BEEN SPOTTY AND MANY AREAS ARE RUNNING MODERATE PRECIP
DEFICITS SINCE JUNE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
246 AM CDT SUN AUG 11 2013
.DISCUSSION...
PRECIPITATION CHANCES THROUGH MONDAY NIGHT PRIMARY FORECAST FOCUS
AS A WEAK FRONT SAGS ACROSS THE FA LATE TODAY INTO MONDAY.
EARLY MORNING SATELLITE/RADAR SHOWED A VORT MAX/TROUGH MOVG SE
ACROSS NWRN MN WITH SEVERAL CONVECTIVE CLUSTERS TO THE SW ON NOSE
OF LOW LEVEL JET/WARM ADVECTION OVR SD INTO NW IA. ALTHOUGH
VARIOUS SHORT TERM MODELS LIKE HOP WRF/RAP KEPT PRECIP MOSTLY NE
OF FA THIS AM ...4KM WRF AND HRRR DID TRY TO DEVELOP SOME OVER NRN
ZONES THIS MORNING. SO SOME SMALL POPS WILL BE MAINTAINED WITH
LAST MINUTE ADJUSTMENTS POSSIBLE BASED ON TRENDS BEFORE ISSUANCE.
OTHERWISE WITH BOUNDARY FORECAST TO SLOWLY SAG INTO NRN ZONES THIS
AFTN...HEATING SHOULD HELP REGENERATE CONVECTION LATER THIS
AFTERNOON...ALTHOUGH 4KM WHICH DEVELOPED IT MOSTLY S OF HIGHWAY 30
APPEARED TOO FAR S. COVERAGE THIS AFTERNOON AND EVOLUTION TONIGHT
IN DOUBT AS H5-H7 QG FORCING WAS NEGLIGIBLE WITH DIFFERENTIAL
HEATING ACROSS BOUNDARY THIS AFTN THEN SYSTEM MOTION FOR INFLOW
WOULD BE PRIMARY DRIVERS AS LOW LEVEL JET WEAKENS FAIRLY
SUBSTANTIALLY THROUGH TONIGHT. THUS KEPT POPS IN CHC CATEGORY FOR
NOW FOR LATE AFTN THROUGH EARLY TONIGHT. WITH THIS LACK OF LOW
LEVEL JET TONIGHT CONFIDENCE NOT VERY HIGH ON HOW MUCH COVERAGE
WILL EXIST AFTER 06Z OVER FA SO GENERALLY TRENDED POPS DOWN AFTER
THAT TIME. WITH MODEL AGREEMENT IN H85 THERMAL RIDGE POKING UP
TOWARD WCNTRL ZONES THIS AFTN BOOSTED HIGHS A BIT...WHICH WERE
STILL BELOW WARMER NAM WHICH ONE OF THESE DAYS MAY ACTUALLY TURN
OUT BETTER IF SWRLY SFC WINDS CAN BE MAINTAINED LONG ENOUGH.
IF CONVECTION TONIGHT PUSHES EFFECTIVE BOUNDARY SOUTH OF FA BY
MONDAY AFTN FURTHER CONVECTIVE DEVELOPMENT COULD BE LIMITED OVER
OUR AREA AND TRENDS WILL NEED MONITORING. HOWEVER...FOR NOW LEFT
IN CHC POPS S WITH SLIGHTS N THROUGH NORFOLK OR SO AS BOUNDARY
PUSH WAS MODEST AT BEST. ALTHOUGH H85 TEMPS DON/T COOL SIGNIFICANTLY
YET ON MONDAY...TEMPERATURES SHOULD BE SOMEWHAT COOLER MOST
AREAS...ESPECIALLY IF DEBRIS CLOUDS CAN BE MAINTAINED. SOME POPS
WERE KEPT THEN MONDAY NIGHT SW 2/3RDS OR SO IN CASE ANY UPSTREAM
CONVECTION WOULD HOLD TOGETHER...ALTHOUGH MUST SAY NOT REALLY SOLD
ON THAT IDEA.
IN FACT...EVEN THOUGH SOME SMALL POPS WERE ALSO MAINTAINED TO INTO
MIDWEEK BEFORE SPREADING E TOWARD FRIDAY...APPEARS BULK OF ANY
ACTIVITY COULD REMAIN TO OUR WEST THROUGH LATE WEEK...ESPECIALLY
PER 00Z ECMWF. THAT MODEL HAS REMAINED FAIRLY CONSISTENT IN THAT
REGARD. PLEASANT TEMPERATURES LOOK IN STORE FOR FORECAST AREA
MUCH OF NEXT WEEK BEFORE MODERATING LATE AS NORTHWESTERLY FLOW
SENDS CANADIAN HIGH PRESSURE DOWN MISSISSIPPI VALLEY. THIS HAS
BEEN ONE OF OUR SAVING GRACES THIS SUMMER AS SIGNIFICANTS RAINS
HAVE BEEN SPOTTY AND MANY AREAS ARE RUNNING MODERATE PRECIP
DEFICITS SINCE JUNE.
CHERMOK
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK AND KOFK.
VFR CONDITIONS PREVAIL THROUGH THE PERIOD WITH SOUTH TO SOUTHEAST
WINDS LESS THAN 10 KNOTS...THEN BECOMING SOUTHWEST BY 15 TO 18Z.
THUNDERSTORM CHANCES RETURN SUNDAY BY 20Z-02Z AT KOFK AS A COLD
FRONT APPROACHES THE REGION. THUNDERSTORMS COULD AFFECT KOMA
00-05Z AND KLNK 02-06Z.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1139 AM MDT SUN AUG 11 2013
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS FORECAST AT AREA TERMINALS OUTSIDE OF SCATTERED
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. MVFR
CIGS/VSBYS LIKELY WITH THUNDERSTORMS LATER TODAY...WITH SOME
SHORT-LIVED IFR CONDITIONS POSSIBLE. TERMINALS MOST LIKELY TO BE
IMPACTED INCLUDE KGUP...KSAF AND KLVS. IMPACTS TO KABQ WILL BE
LATER IF AT ALL...BETWEEN 00-03Z.
11
&&
.PREV DISCUSSION...927 AM MDT SUN AUG 11 2013...
UPDATED MORNING PRECIPITATION CHANCES AND SKY COVER FOR NORTH-CENTRAL
AND WESTERN AREAS. RAIN COOLED/STABLE ATMOSPHERE IN PLACE THIS MORNING
OVER THESE AREAS SO NOT EXPECTING MUCH IN THE WAY OF CLOUDS AND/OR
SHOWERS. ALSO TRENDED DOWN POPS FOR THE RG VALLEY AND SAN JUAN RIVER
VALLEY FOR THIS AFTERNOON WITH MOST ACTIVITY HOLDING OFF UNTIL EARLY
EVENING AFTER SFC HEATING WORKS AWAY AT SUBSIDENCE INVERSION BEHIND
DEPARTING WAVE/MCV.
33
.PREV DISCUSSION...330 AM MDT SUN AUG 11 2013...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
927 AM MDT SUN AUG 11 2013
.UPDATE...
UPDATED MORNING PRECIPITATION CHANCES AND SKY COVER FOR NORTH-CENTRAL
AND WESTERN AREAS. RAIN COOLED/STABLE ATMOSPHERE IN PLACE THIS MORNING
OVER THESE AREAS SO NOT EXPECTING MUCH IN THE WAY OF CLOUDS AND/OR
SHOWERS. ALSO TRENDED DOWN POPS FOR THE RG VALLEY AND SAN JUAN RIVER
VALLEY FOR THIS AFTERNOON WITH MOST ACTIVITY HOLDING OFF UNTIL EARLY
EVENING AFTER SFC HEATING WORKS AWAY AT SUBSIDENCE INVERSION BEHIND
DEPARTING WAVE/MCV.
33
&&
.PREV DISCUSSION...538 AM MDT SUN AUG 11 2013...
.AVIATION...
12Z TAF CYCLE
WIDESPREAD SHOWERS AND A FEW TSRA CONTINUE SOUTH OF AN ABQ TO TCC
LINE. THIS ACTIVITY WILL CONTINUE INTO THE MID MORNING HOURS. LOW
VSBYS WILL BE POSSIBLE WITH THE HEAVIER SHOWERS...MAINLY AROUND
KCVS AND KCVN. CONFIDENCE IS NOT HAS HIGH FOR IFR CIGS NEAR ROW
THIS MORNING AS MID LEVEL CLOUD COVER HAS LINGERED OVER THE AREA.
OTHERWISE...THIS AFTERNOONS CONVECTION SHOULD START A BIT LATER
TODAY. STORMS WILL TEND TO FAVOR THE HIGH TERRAIN INITIALLY BEFORE
MOVING EAST OVER THE LOWER ELEVATIONS. OVERALL...STORMS SHOULD
NOT BE AS WIDESPREAD AS YDAY. LOCALLY HEAVY RAIN AND SMALL HAIL
WILL AGAIN BE A CONCERN WITH THE STRONGER STORMS.
34
.PREV DISCUSSION...330 AM MDT SUN AUG 11 2013...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
538 AM MDT SUN AUG 11 2013
.AVIATION...
12Z TAF CYCLE
WIDESPREAD SHOWERS AND A FEW TSRA CONTINUE SOUTH OF AN ABQ TO TCC
LINE. THIS ACTIVITY WILL CONTINUE INTO THE MID MORNING HOURS. LOW
VSBYS WILL BE POSSIBLE WITH THE HEAVIER SHOWERS...MAINLY AROUND
KCVS AND KCVN. CONFIDENCE IS NOT HAS HIGH FOR IFR CIGS NEAR ROW
THIS MORNING AS MID LEVEL CLOUD COVER HAS LINGERED OVER THE AREA.
OTHERWISE...THIS AFTERNOONS CONVECTION SHOULD START A BIT LATER
TODAY. STORMS WILL TEND TO FAVOR THE HIGH TERRAIN INITIALLY BEFORE
MOVING EAST OVER THE LOWER ELEVATIONS. OVERALL...STORMS SHOULD
NOT BE AS WIDESPREAD AS YDAY. LOCALLY HEAVY RAIN AND SMALL HAIL
WILL AGAIN BE A CONCERN WITH THE STRONGER STORMS.
34
&&
.PREV DISCUSSION...330 AM MDT SUN AUG 11 2013...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
330 AM MDT SUN AUG 11 2013
.DISCUSSION...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
&&
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.AVIATION...
06Z TAF CYCLE
WIDESPREAD TSRA ACROSS MUCH OF THE AREA ALONG AND SOUTH OF I40 IS
MERGING INTO A LARGE SHIELD OF STRATIFORM RAINFALL SURROUNDING THE
ABQ METRO AREA. ANOTHER LARGE RAIN SHIELD WITH EMBEDDED THUNDER IS
SLIDING NORTHEAST OUT OF SOUTHERN NM WHERE VERY RICH MOISTURE IS
INTERACTING WITH AN UPPER LEVEL WAVE. CONFIDENCE HIGH ON RAINFALL
FOR AREAS ALONG AND SOUTH OF I-40 FOR REST OF TONIGHT...WITH THE
LOWEST CIGS AROUND KROW. MODEL SOUNDINGS INDICATE IFR CONDITIONS
BY MORNING OVER THIS REGION. THICK CLOUD COVER WILL LINGER OVER
THE REGION THROUGH MID MORNING WITH EVEN SOME SHOWERS CONTINUING
OVER THE EASTERN PLAINS. STORMS SHOULD BE LATE TO FIRE UP ACROSS
THE REGION SUNDAY AS HEATING WILL BE HARD TO COME BY UNTIL AFT 21Z.
GUYER
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 85 59 88 61 / 30 20 20 10
DULCE........................... 79 50 81 51 / 30 30 30 20
CUBA............................ 80 51 80 53 / 40 30 30 20
GALLUP.......................... 81 52 82 58 / 40 30 30 20
EL MORRO........................ 77 52 78 53 / 50 30 40 20
GRANTS.......................... 78 52 81 57 / 40 40 40 20
QUEMADO......................... 78 51 81 55 / 50 40 40 20
GLENWOOD........................ 83 58 87 61 / 40 40 20 20
CHAMA........................... 74 46 75 47 / 40 30 40 30
LOS ALAMOS...................... 78 55 81 56 / 40 30 30 20
PECOS........................... 77 54 80 55 / 40 30 30 20
CERRO/QUESTA.................... 78 47 77 49 / 30 30 40 30
RED RIVER....................... 69 45 67 45 / 50 30 50 30
ANGEL FIRE...................... 73 46 75 46 / 40 30 50 30
TAOS............................ 79 49 81 51 / 30 20 30 20
MORA............................ 76 51 76 51 / 40 30 40 30
ESPANOLA........................ 83 55 86 59 / 30 30 20 20
SANTA FE........................ 79 53 82 59 / 30 30 30 20
SANTA FE AIRPORT................ 82 56 84 59 / 30 20 20 20
ALBUQUERQUE FOOTHILLS........... 82 60 86 61 / 40 30 30 20
ALBUQUERQUE HEIGHTS............. 83 63 86 67 / 30 30 20 20
ALBUQUERQUE VALLEY.............. 85 60 89 65 / 30 30 20 20
ALBUQUERQUE WEST MESA........... 84 62 87 66 / 30 30 20 20
LOS LUNAS....................... 85 61 89 65 / 30 30 20 20
RIO RANCHO...................... 85 62 87 66 / 30 30 20 20
SOCORRO......................... 86 62 87 65 / 40 40 30 20
SANDIA PARK/CEDAR CREST......... 80 58 84 55 / 40 30 30 20
TIJERAS......................... 82 58 85 59 / 30 30 30 20
MORIARTY/ESTANCIA............... 81 55 83 58 / 40 30 30 20
CLINES CORNERS.................. 78 55 81 59 / 40 30 40 20
GRAN QUIVIRA.................... 79 56 81 60 / 40 40 30 20
CARRIZOZO....................... 82 60 83 62 / 40 30 20 20
RUIDOSO......................... 74 57 75 56 / 60 40 40 20
CAPULIN......................... 80 51 82 55 / 50 20 30 30
RATON........................... 82 53 83 55 / 40 20 30 30
SPRINGER........................ 81 53 86 57 / 40 20 30 30
LAS VEGAS....................... 78 53 81 56 / 40 30 30 20
CLAYTON......................... 88 61 89 63 / 30 20 30 30
ROY............................. 86 58 85 62 / 40 20 30 30
CONCHAS......................... 87 63 92 68 / 30 20 20 20
SANTA ROSA...................... 87 62 90 64 / 30 20 20 20
TUCUMCARI....................... 89 65 92 68 / 30 20 20 20
CLOVIS.......................... 87 64 89 66 / 40 20 20 10
PORTALES........................ 86 66 90 68 / 30 20 20 10
FORT SUMNER..................... 87 65 91 67 / 40 20 20 10
ROSWELL......................... 89 67 92 70 / 40 20 20 10
PICACHO......................... 83 61 86 64 / 50 30 20 20
ELK............................. 77 59 81 60 / 60 40 20 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
905 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TONIGHT AND PASS THROUGH THE
REGION ON TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. FAIR
AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY MODERATING
TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
900 PM EDT UPDATE...
ISOLATED LIGHT RAIN SHOWERS HAS DEVELOPED ACROSS THE REGION TONIGHT
WHERE WAA AND THETA-E ADVECTION IS TAKING PLACE AHEAD OF AN
APPROACHING UPPR LOW. VORT MAXES ARE BEING EJECTED FROM THE BASE OF
THE TROUGH AND ARE MOVING WITHIN THE CYCLONIC FLOW OVER THE
REGION...THUS EXPECT THESE SHOWERS TO CONTINUE AHEAD OF THE FROPA.
AS THE WAA CONTINUES OVERNIGHT...EXPECT SHOWERS TO BECOME MORE
SCATTERED LIKE IN NATURE.
SKY COVERAGE HAS INCREASED OVER THE REGION THUS DO NOT BELIEVE
THAT TEMPS WILL FALL MUCH FURTHER TONIGHT AS DENSE COVERAGE WILL
INHIBIT HEAT LOSS.
PREVIOUS FORECAST HOLDS GOOD AS FROPA IS EXPECTED TO MOVE THROUGH
TUESDAY MORNING.
PREVIOUS FORECAST...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
00Z UPDATE...
HAVE BACKED OFF TIMING ON SHOWERS BY ABOUT 4-6 HOURS AS WAVES ARE
SLOWING DOWN AND HAVING A HARD TIME GENERATING MUCH IN THE WAY OF
PRECIPITATION.
SHOWERS WILL BREAK OUT BETWEEN 06Z (AT WESTERN TERMINALS) AND 09Z
(AT FAR EASTERN TERMINALS) AS UPPER LEVEL WAVE APPROACHES FROM THE
SOUTHWEST. MVFR VSBYS WILL ACCOMPANY THIS FIRST AREA OF SHOWERS
WITH VSBYS AROUND 4-5SM. SCATTERED CLOUDS AROUND 1500-2500 FEET
WILL BE PRESENT, HOWEVER THINKING CIGS WILL BE VFR. FRONT WILL
APPROACH FROM THE NORTH DURING THE MORNING HOURS DROPPING CIGS
INTO MVFR RANGE AFTER 13Z. SHOWERS WILL CONTINUE THROUGH THE
PERIOD BUT RESTRICTIONS WILL RISE TO VFR AFTER 20Z.
AS FRONT APPROACHES DURING THE AFTERNOON POTENTIAL EXISTS FOR
THUNDER BUT HAVE NOT MENTIONED IN TAFS AT THIS TIME DUE TO
UNCERTAINTY.
WINDS WILL START OUT LGT/VRB BEFORE BECOMING MORE DEFINITELY OUT
OF THE S-SW AFTER MIDNIGHT. WINDS WILL SHIFT AROUND TO THE NW
AFTER FRONT PASSES AROUND 20Z TUESDAY.
OUTLOOK...
TUE NGT...A PD OF MVFR CIGS PSBL...SPCLY ACRS CNY.
WED THRU SAT...MAINLY VFR. THE ONLY EXCEPTION WILL BE PSBL EARLY
AM VLY FOG AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KAH
SHORT TERM...
LONG TERM...CMG/MLJ
AVIATION...MLJ/PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
742 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA LATER TONIGHT AND PASS THROUGH
THE REGION ON TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS.
FAIR AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY
MODERATING TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
00Z UPDATE...
HAVE BACKED OFF TIMING ON SHOWERS BY ABOUT 4-6 HOURS AS WAVES ARE
SLOWING DOWN AND HAVING A HARD TIME GENERATING MUCH IN THE WAY OF
PRECIPITATION.
SHOWERS WILL BREAK OUT BETWEEN 06Z (AT WESTERN TERMINALS) AND 09Z
(AT FAR EASTERN TERMINALS) AS UPPER LEVEL WAVE APPROACHES FROM THE
SOUTHWEST. MVFR VSBYS WILL ACCOMPANY THIS FIRST AREA OF SHOWERS
WITH VSBYS AROUND 4-5SM. SCATTERED CLOUDS AROUND 1500-2500 FEET
WILL BE PRESENT, HOWEVER THINKING CIGS WILL BE VFR. FRONT WILL
APPROACH FROM THE NORTH DURING THE MORNING HOURS DROPPING CIGS
INTO MVFR RANGE AFTER 13Z. SHOWERS WILL CONTINUE THROUGH THE
PERIOD BUT RESTRICTIONS WILL RISE TO VFR AFTER 20Z.
AS FRONT APPROACHES DURING THE AFTERNOON POTENTIAL EXISTS FOR
THUNDER BUT HAVE NOT MENTIONED IN TAFS AT THIS TIME DUE TO
UNCERTAINTY.
WINDS WILL START OUT LGT/VRB BEFORE BECOMING MORE DEFINITELY OUT
OF THE S-SW AFTER MIDNIGHT. WINDS WILL SHIFT AROUND TO THE NW
AFTER FRONT PASSES AROUND 20Z TUESDAY.
OUTLOOK...
TUE NGT...A PD OF MVFR CIGS PSBL...SPCLY ACRS CNY.
WED THRU SAT...MAINLY VFR. THE ONLY EXCEPTION WILL BE PSBL EARLY
AM VLY FOG AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...CMG/MLJ
AVIATION...MLJ/PVN
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
641 PM EDT SUN AUG 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THIS EVENING. A
STORM SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH THE NORTH
COUNTRY LATE MONDAY AFTERNOON WITH SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED INTO TUESDAY. THE FRONT WILL SLOWLY PUSH
EASTWARD TUESDAY NIGHT USHERING IN A COOL AND DRY CANADIAN
AIRMASS. TEMPERATURES THROUGH THE REST OF THE WORKWEEK WILL BE A
FEW DEGREES BELOW NORMAL FOR MID-AUGUST.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
AS OF 641 PM EDT SUNDAY...LATE-AFTERNOON VISIBLE SATELLITE TRENDS
SHOW DIURNALLY-DRIVEN FAIR WEATHER STRATOCUMULUS QUICKLY ERODING.
LOOKING UPSTREAM HOWEVER...A BROAD SWATH OF BROKEN TO OVERCAST
4000-6000 FT CEILINGS IS QUICKLY MOVING INTO WESTERN NEW YORK AND
THE NORTHERN SHORE OF LAKE ONTARIO. THESE CLOUDS ARE EMBEDDED IN
FAST ZONAL FLOW ALOFT /40-50KTS AT 500 MB PER RAP MODEL ANALYSES/.
THESE WILL MOVE WEST-TO- EAST OVER THE SOUTHERN SAINT LAWRENCE
VALLEY...NORTHERN ADIRONDACKS...AND INTO SOUTHERN VERMONT THROUGH
MIDNIGHT. SO I HAVE INCREASED CLOUD COVER THROUGH MIDNIGHT IN
THESE AREAS...THOUGH QUICKLY CLEARING AS PER SATELLITE TRENDS
ACROSS THE NORTHERN LAKES. I ALSO ADJUSTED LOW TEMPERATURES UP A
DEGREE OR SO GIVEN THE GREATER COVERAGE IN CLOUDS. ASIDE FROM
THESE MINOR ADJUSTMENTS THE GOING FORECAST LOOKS GOOD AT THIS
POINT WITH NO OTHER CHANGES MADE.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 337 PM EDT SUNDAY...INCREASING CLOUDS EXPECTED ON MONDAY
AHEAD OF AN APPROACHING UPPER LEVEL TROUGH MOVING SOUTHEASTWARD
OUT OF NORTHERN ONTARIO. ITS ASSOCIATED SFC COLD FRONT WILL BE
SLOW TO MOVE SOUTHEASTWARD WITH 500 MB FLOW BEING NEARLY PARALLEL
TO THE SFC FRONT. SO HAVE SLOWED THE ONSET OF SLIGHT CHANCE
PRECIPITATION PROBABILITIES INTO THE SAINT LAWRENCE VALLEY UNTIL
AFTER 18Z MONDAY WITH THAT IDEA IN MIND...AND A SLOW EASTWARD
INCREASE THROUGH THE EVENING UP TO HIGH CHANCE/LOW LIKELY BY 12Z
TUESDAY. HIGHS MONDAY IN THE 70S WITH A FEW LOW 80S POSSIBLE IN
THE CHAMPLAIN VALLEY & LOWS IN THE 50S TO LOW 60S.
THE FRONT WILL BE SLOWLY PUSHING SOUTHEASTWARD ACROSS THE REGION ON
TUESDAY. THINK THAT THUNDER IS POSSIBLE BUT MAINLY FROM THE
CHAMPLAIN VALLEY SOUTH AND EAST. IN FACT THE COMBINATION OF
STRONGEST DYNAMICS AS WELL AS SOME MODEST INSTABILITY /CAPE VALUES
800-1000 J/KG/ SUGGESTS THE BEST CHANCE FOR THUNDER WILL BE ACROSS
CENTRAL AND SOUTHERN VERMONT. WHILE LIKELY POPS ARE INDICATED FOR
MOST OF THE AREA ON TUESDAY...HAVE INCLUDED CHANCE THUNDER FOR
CENTRAL AND SOUTHERN VERMONT WITH SLIGHT CHANCE THUNDER FOR THE REST
OF VERMONT FOR TUESDAY AFTERNOON. FRONT LOOKS TO PUSH THROUGH THE
AREA AFTER 00Z WEDNESDAY WITH SOME LINGERING SHOWERS UNTIL THE FRONT
CLEARS FOR EASTERN VERMONT. GENERALLY THINK IT`S A LIGHT TO MODERATE
QPF EVENT WITH 36 HR QPF TOTALS FROM .25" TO .50".
STRONG COLD AIR ADVECTION BEHIND THE FRONT ON TUESDAY NIGHT WITH 850
TEMPERATURES DROPPING TO +4C TO +6C SHOULD ALLOW FOR LOW
TEMPERATURES TO DROP INTO THE 40S TO LOW 50S. DUE TO SOME QUESTION
AS TO HOW MUCH CLOUD COVER WILL BE LEFT OVER HAVE OPTED TO LEAN
SLIGHTLY WARMER. IF SKIES CAN CLEAR OUT FURTHER IT MAY BE A FEW
DEGREES COOLER THAN SHOWN HOWEVER.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 337 PM EDT SUNDAY...NORTHWEST FLOW ALOFT DEVELOPS ON
BACKSIDE OF UPPER TROUGH ON WEDNESDAY. DRIER WEATHER IS
EXPECTED...BUT COLD AIR ADVECTION WILL RESULT IN HIGH TEMPERATURES
BEING SEVERAL DEGREES BELOW NORMAL. UPPER TROUGH TO PERSIST OVER
EASTERN CANADA THURSDAY AND FRIDAY FOR A CONTINUATION OF THE DRY
WEATHER WITH SLOWLY MODERATING TEMPERATURES...BUT VALUES WILL
STILL BE SLIGHTLY BELOW NORMAL. EVENTUALLY THE FLOW ALOFT BACKS TO
THE WEST AND SOUTHWEST OVER THE WEEKEND...SO THE WARMING TREND
WILL CONTINUE TO APPROACH SEASONAL LEVELS. DRY WEATHER WILL
CONTINUE TO BE THE RULE. IF THERE IS ANY CHANCE FOR SHOWERS...A
SMALL CHANCE AT BEST...IT WOULD BE ON FRIDAY AS A WEAK FRONT DROPS
DOWN INTO THE AREA FROM THE NORTH.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...STILL LOOKING AT VFR CONDITIONS THROUGH MOST
OF THE PERIOD. THE ONLY EXCEPTION TO THIS WILL BE A PERIOD OF IFR
TO VLIFR CONDITIONS AT KSLK AND KMPV BETWEEN 07Z AND 12Z.
OTHERWISE...WINDS WILL BE VARIABLE AT SPEEDS UNDER 10 KNOTS
THROUGH MUCH OF THE PERIOD.
OUTLOOK 18Z MONDAY THROUGH THURSDAY...
18Z MONDAY THROUGH 00Z TUESDAY...MAINLY VFR UNDER SURFACE HIGH
PRESSURE.
00Z TUESDAY THROUGH 00Z WEDNESDAY...OCNL MVFR IN RAIN SHOWERS AS COLD
FRONT MOVES ACROSS THE REGION.
00Z WEDNESDAY THROUGH 00Z SATURDAY...MAINLY VFR AS HIGH PRESSURE RETURNS
TO THE REGION.
&&
.EQUIPMENT...
AS OF 337 PM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LOCONTO
NEAR TERM...LOCONTO
SHORT TERM...LOCONTO
LONG TERM...EVENSON
AVIATION...EVENSON/WGH
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1253 PM EDT SUN AUG 11 2013
.SYNOPSIS...
A LARGE HIGH PRESSURE SYSTEM WILL REMAIN IN CONTROL OF THE WEATHER
PATTERN TODAY...ALLOWING FOR ONE MORE COMFORTABLE AND RAIN FREE
DAY ACROSS OUR REGION. HIGH TEMPERATURES WILL WARM INTO THE LOWER
TO MIDDLE 70S ACROSS MUCH OF THE AREA...WITH A FEW LOW 80S POSSIBLE
ACROSS THE LOWER WYOMING VALLEY. BY MONDAY...RAIN CHANCES WILL
INCREASE DURING THE LATE AFTERNOON AS A WEAK AREA OF LOW PRESSURE
BEGINS MOVING NORTH ALONG THE MID-ATLANTIC COAST. BY MONDAY NIGHT
AND TUESDAY...EXPECT RAIN CHANCES TO INCREASE AS A STRONG COLD
FRONT MOVES THROUGH THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
945 AM UPDATE... MORE IN THE WAY OF CLDNS...ALG WITH ISOLD
-SHRA/SPRINKLES WERE ADDED TO THE FCST TDY FOR OUR FAR SRN ZNS.
OTHWS...NO SIG CHGS ATTM.
SAT/RADAR IMAGERY SHOW A CLOUD BAND (GENERALLY 4-7 K FT AGL) MOVG
ACRS PA LATE THIS MRNG...ALG WITH POTENTIALLY A FEW SPRINKLES. A
CLOSER INSPECTION OF THE THERMAL/MOISTURE FIELDS SHOW SOME 850 MB
FGEN THIS RGN...OWING TO A NARROW RGN OF CONVERGENT FLOW...AND
ASSOCD MOIST CONDS/HIGHER DEW PTS. THE LATEST HRRR RUNS SEEM TO
PICK UP ON THIS SCENARIO...AND SHOW SOME WEAK RETURNS MOVG ACRS
PTNS OF NE PA THROUGH MID TO LATE AFTN. ALTHOUGH WE CERTAINLY
DON`T EXPECT MUCH PCPN OUT OF THIS...WE FELT IT PRUDENT TO THROW
IN ISOLD SHWRS/SPRINKLES...AND OBVIOUSLY INSERT ADDTNL CLOUD
COVER OVER THE NEAR-TERM.
DUE TO THE SHALLOW NATURE OF THE AFOREMENTIONED AREA OF
MOISTURE...WE THINK IT COULD MIX OUT TO SOME DEGREE DURG THE
AFTN. THUS...WE`RE ONLY CARRYING ISOLD/SCHC POPS TIL 18-21Z.
ALSO...WE THINK SOME BREAKS OF SUNSHINE ARE LIKELY TO DVLP THIS
AFTN OVER SRN PTNS OF THE FA...AND GIVEN THIS...WE DIDN`T DEVIATE
MUCH FROM OUR EARLIER HIGH TEMP FCST (GENERALLY 75-80 DEGS).
FARTHER N ACRS CNY...LIFE IS GOOD...WITH A DRY AMS/SINKING MOTION
REGIME IN PLACE. ONLY SOME SPOTTY FAIR WX CU IS ANTICIPATED...WITH
A GENERALLY SUNNY AFTN ON TAP.
PREV DISC... 08Z MSAS SURFACE ANALYSIS SHOWING A LARGE AREA OF
HIGH PRESSURE EXTENDING ACROSS MUCH OF THE GREAT LAKES REGION THIS
MORNING...WITH TEMPS LARGELY HOVERING IN THE LWR 50S. 11-3.9U
SATELLITE IMAGERY SHOWING A FEW PATCHES OF MID-LEVEL CLOUDS
STREAMING ACROSS THE REGION AS MOISTURE REMAINS TRAPPED BELOW A
FAIRLY STRONG SUBSIDENCE INVERSION WHICH IS READILY APPARENT ON
THE 00Z BUF RAOB. HEADING INTO TODAY...THESE CLOUDS WILL LIKELY
DISSIPATE AS DAYTIME HEATING COMMENCES BEFORE SOME SCATTERED FLAT
CU DEVELOP BY LATE MORNING AND EARLY AFTERNOON.
WITH NO SENSIBLE WX EXPECTED TODAY...MAIN FCST ISSUE REMAINS
CENTERED ON DAYTIME TEMPS. 850 TEMPS ARE FORECAST TO RISE A DEGREE
OR TWO OVER YESTERDAY/S VALUES...HOWEVER LOW-LEVEL FLOW WILL
REMAIN FROM THE NORTHWEST THROUGH A GOOD CHUNK OF THE DAY.
CONSIDERING MOST LOCATIONS UP ACROSS THE LAKE PLAIN REMAINED A FEW
DEGREES BELOW MODEL GUIDANCE ON SATURDAY...HAVE ELECTED TO
MAINTAIN A SIMILAR TREND TODAY WITH LOW TO MID 70S EXPECTED UP
NORTH...WITH MID TO UPPER 70S ANTICIPATED FROM THE TWIN TIERS
SOUTH.
A SIMILAR NIGHT EXPECTED TONIGHT WITH HIGH PRESSURE REMAINING IN
CONTROL OF THE WX PATTERN. THE ONLY POTENTIAL FLY IN THE OINTMENT
WILL BE A WEAK SHORTWAVE MOVING EAST THROUGH CENTRAL PA OVERNIGHT
WITH THE GFS OFFERING SOME LIGHT SHWR ACTIVITY ACROSS SOUTHEASTERN
PA AS WEAK WARM AIR ADVECTION INTERACTS WITH A MARINE FRONT.
THERE IS SOME POTENTIAL THAT SOME SHWRS MAY TRY BUILDING UP
TOWARDS OUR NE PA ZONES HOWEVER DECIDED TO LEAVE THE FCST DRY
CONSIDERING HOW DRY THE ATMOSPHERE CURRENTLY IS. WILL ALLOW THE
DAY SHIFT TO TAKE ANOTHER LOOK BEFORE DECIDED WHETHER A MENTION
WILL BE NEEDED. OVERNIGHT LOWS WILL AGAIN FALL INTO THE LOWER TO
MIDDLE 50S WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED
ALOFT. THIS SHOULD ALLOW FOR GREAT VIEWING CONDITIONS OF THE
PERSEID`S METEOR SHOWER.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
CLOUDS TO BE ON THE INCREASE THROUGH THE DAY ON MONDAY AS STRONG
SHORTWAVE TROUGH ROTATES SOUTHEAST FROM WESTERN ONTARIO INTO THE
NORTH-CENTRAL LAKES. AS THIS OCCURS...STRENGTHENING SFC LOW
PRESSURE WILL BEGIN TRACKING FROM NORTHERN MICHIGAN INTO SOUTH-
CENTRAL ONTARIO...WITH A COLD FRONT EXTENDING WELL SOUTH THROUGH
THE OHIO VLY. A RETURN OF SOUTHERLY WINDS IN ADVANCE OF BOTH
FEATURES WILL LEAD TO INCREASING MOISTURE ADVECTION THROUGH THE
DAY WITH FCST MODELS HIGHLIGHTING POSSIBLE SHOWERS/ISO STORMS
ACROSS THE WESTERN ZONES BY LATE AFTERNOON...WITH ANOTHER AREA OF
SHWRS POSSIBLE ACROSS FROM NORTHEAST PA NORTH INTO THE CATSKILLS
AS AFOREMENTIONED MARINE FRONT LIFTS NORTH TOWARDS THE REGION.
BOTH THE GFS AND NAM SHOW A SHORTWAVE MOVING ACROSS THE REGION
DURING THE AFTERNOON OFFERING A LITTLE SYNOPTIC SCALE FORCING FOR
POSSIBLE DEVELOPMENT. AS SUCH...HAVE INCREASED POPS INTO THE CHC
CATEGORY BEGINNING IN THE AFTERNOON FROM THE TWIN TIERS AND
WESTERN FINGER LAKES SOUTH...BEFORE RISING POPS FURTHER TO THE
NORTH BY THE END OF THE PERIOD. INSTABILITY LOOKS MEAGER AT BEST
ONCE AGAIN HOWEVER WITH A FEW HUNDRED JOULES POTENTIALLY
AVAILABLE...HAVE DECIDED TO OFFER AN ISOLATED THUNDER MENTION.
MAIN COLD FRONT TO SLIDE THROUGH THE AREA ON TUESDAY WITH ALL
INDICATIONS SUGGESTING THE COLD FRONT WILL BEGIN MOVING THROUGH
OUR AREA BETWEEN THE 12-15Z TIME FRAME. BEYOND THIS...FEATURE WILL
QUICKLY RACE TO THE SOUTHEAST AS MAIN EASTERN CANADIAN CLOSED LOW
RETREATS TOWARDS EASTERN QUEBEC AND TRAILING SHORTWAVE ENERGY
QUICKLY SETTLES SOUTH ACROSS OUR AREA. THUS EXPECT A GRADUAL
DECREASE IN SHWRS/ISO STORMS THROUGH THE EVENING WITH DRY BUT COOL
CONDITIONS THEN ANTICIPATED TUE NIGHT. FOR NOW...MODEL TRENDS
SUGGEST BEST INSTABILITY WILL BE EAST OF OUR REGION LENDING HOPE
THAT ANY ORGANIZED SEVERE WX WILL NOT IMPACT OUT AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
LTL CHG TO THE MED RNG FCST WTIH WPC GDNC LOOKING GOOD. SFC HIGH
PRESSURE IN THE VICINITY...WITH A BEAUTIFUL STRETCH OF WEATHER FOR LATE
SUMMER. POTNL FOR SOME -SHRA LATE IN THE PD IF WE CAN GET SOME
ATLC MSTR INTO THE AREA. TEMPS MODIFYING TO NEAR SEASONAL NORMS
FOR DAYTIME HIGHS...BUT THE NIGHTS WILL CONTINUE TO BE ON THE COOL
SIDE UNTIL LATE IN THE WEEK.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR TO PREVAIL THRU 18Z MON. DIURNAL CU WILL DSPT LATER THIS
AFTN...WITH GNRLY SKC EARLY THIS EVNG GIVING WAY TO SOME SCT-BKN
MID AND HI CLDS TNGT. THESE CLDS MAKE THE ELM FOG FCST
INTERESTING...AS OTHER PARAMS LOOK QUITE FVRBL FOR REDVLPMNT OF
VLY FOG TNGT. CHECKLIST ALSO INDICATES A GOOD CHC FOR DENSE FOG.
FOR NOW WE`LL GO WITH A 2SM BR TEMPO 1/2 FG FROM 09-12Z...WHICH
WILL HAVE TO BE REVISITED IN LATER UPDATES. FOR TMRW...PSSG OF A
MID LVL S/WV WITH BKN100 XPCTD TO PREVAIL. WINDS THIS AFTN ARND 5
KTS MAINLY FROM THE W OR NW...L&V TNGT WITH TYPICAL DRAINAGE
FLOWS...THEN WRLY ON MON 5-10 KTS.
OUTLOOK...
MON NGT/TUE...MVFR IN SHRA/TSRA.
WED/THU/FRI...VFR...BRIEF IFR PSBL AT ELM IN EARLY MRNG VLY FOG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/MLJ
SHORT TERM...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
949 AM EDT SUN AUG 11 2013
.SYNOPSIS...
A LARGE HIGH PRESSURE SYSTEM WILL REMAIN IN CONTROL OF THE WEATHER
PATTERN TODAY...ALLOWING FOR ONE MORE COMFORTABLE AND RAIN FREE
DAY ACROSS OUR REGION. HIGH TEMPERATURES WILL WARM INTO THE LOWER
TO MIDDLE 70S ACROSS MUCH OF THE AREA...WITH A FEW LOW 80S POSSIBLE
ACROSS THE LOWER WYOMING VALLEY. BY MONDAY...RAIN CHANCES WILL
INCREASE DURING THE LATE AFTERNOON AS A WEAK AREA OF LOW PRESSURE
BEGINS MOVING NORTH ALONG THE MID-ATLANTIC COAST. BY MONDAY NIGHT
AND TUESDAY...EXPECT RAIN CHANCES TO INCREASE AS A STRONG COLD
FRONT MOVES THROUGH THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
945 AM UPDATE... MORE IN THE WAY OF CLDNS...ALG WITH ISOLD
-SHRA/SPRINKLES WERE ADDED TO THE FCST TDY FOR OUR FAR SRN ZNS.
OTHWS...NO SIG CHGS ATTM.
SAT/RADAR IMAGERY SHOW A CLOUD BAND (GENERALLY 4-7 K FT AGL) MOVG
ACRS PA LATE THIS MRNG...ALG WITH POTENTIALLY A FEW SPRINKLES. A
CLOSER INSPECTION OF THE THERMAL/MOISTURE FIELDS SHOW SOME 850 MB
FGEN THIS RGN...OWING TO A NARROW RGN OF CONVERGENT FLOW...AND
ASSOCD MOIST CONDS/HIGHER DEW PTS. THE LATEST HRRR RUNS SEEM TO
PICK UP ON THIS SCENARIO...AND SHOW SOME WEAK RETURNS MOVG ACRS
PTNS OF NE PA THROUGH MID TO LATE AFTN. ALTHOUGH WE CERTAINLY
DON`T EXPECT MUCH PCPN OUT OF THIS...WE FELT IT PRUDENT TO THROW
IN ISOLD SHWRS/SPRINKLES...AND OBVIOUSLY INSERT ADDTNL CLOUD
COVER OVER THE NEAR-TERM.
DUE TO THE SHALLOW NATURE OF THE AFOREMENTIONED AREA OF
MOISTURE...WE THINK IT COULD MIX OUT TO SOME DEGREE DURG THE
AFTN. THUS...WE`RE ONLY CARRYING ISOLD/SCHC POPS TIL 18-21Z.
ALSO...WE THINK SOME BREAKS OF SUNSHINE ARE LIKELY TO DVLP THIS
AFTN OVER SRN PTNS OF THE FA...AND GIVEN THIS...WE DIDN`T DEVIATE
MUCH FROM OUR EARLIER HIGH TEMP FCST (GENERALLY 75-80 DEGS).
FARTHER N ACRS CNY...LIFE IS GOOD...WITH A DRY AMS/SINKING MOTION
REGIME IN PLACE. ONLY SOME SPOTTY FAIR WX CU IS ANTICIPATED...WITH
A GENERALLY SUNNY AFTN ON TAP.
PREV DISC... 08Z MSAS SURFACE ANALYSIS SHOWING A LARGE AREA OF
HIGH PRESSURE EXTENDING ACROSS MUCH OF THE GREAT LAKES REGION THIS
MORNING...WITH TEMPS LARGELY HOVERING IN THE LWR 50S. 11-3.9U
SATELLITE IMAGERY SHOWING A FEW PATCHES OF MID-LEVEL CLOUDS
STREAMING ACROSS THE REGION AS MOISTURE REMAINS TRAPPED BELOW A
FAIRLY STRONG SUBSIDENCE INVERSION WHICH IS READILY APPARENT ON
THE 00Z BUF RAOB. HEADING INTO TODAY...THESE CLOUDS WILL LIKELY
DISSIPATE AS DAYTIME HEATING COMMENCES BEFORE SOME SCATTERED FLAT
CU DEVELOP BY LATE MORNING AND EARLY AFTERNOON.
WITH NO SENSIBLE WX EXPECTED TODAY...MAIN FCST ISSUE REMAINS
CENTERED ON DAYTIME TEMPS. 850 TEMPS ARE FORECAST TO RISE A DEGREE
OR TWO OVER YESTERDAY/S VALUES...HOWEVER LOW-LEVEL FLOW WILL
REMAIN FROM THE NORTHWEST THROUGH A GOOD CHUNK OF THE DAY.
CONSIDERING MOST LOCATIONS UP ACROSS THE LAKE PLAIN REMAINED A FEW
DEGREES BELOW MODEL GUIDANCE ON SATURDAY...HAVE ELECTED TO
MAINTAIN A SIMILAR TREND TODAY WITH LOW TO MID 70S EXPECTED UP
NORTH...WITH MID TO UPPER 70S ANTICIPATED FROM THE TWIN TIERS
SOUTH.
A SIMILAR NIGHT EXPECTED TONIGHT WITH HIGH PRESSURE REMAINING IN
CONTROL OF THE WX PATTERN. THE ONLY POTENTIAL FLY IN THE OINTMENT
WILL BE A WEAK SHORTWAVE MOVING EAST THROUGH CENTRAL PA OVERNIGHT
WITH THE GFS OFFERING SOME LIGHT SHWR ACTIVITY ACROSS SOUTHEASTERN
PA AS WEAK WARM AIR ADVECTION INTERACTS WITH A MARINE FRONT.
THERE IS SOME POTENTIAL THAT SOME SHWRS MAY TRY BUILDING UP
TOWARDS OUR NE PA ZONES HOWEVER DECIDED TO LEAVE THE FCST DRY
CONSIDERING HOW DRY THE ATMOSPHERE CURRENTLY IS. WILL ALLOW THE
DAY SHIFT TO TAKE ANOTHER LOOK BEFORE DECIDED WHETHER A MENTION
WILL BE NEEDED. OVERNIGHT LOWS WILL AGAIN FALL INTO THE LOWER TO
MIDDLE 50S WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED
ALOFT. THIS SHOULD ALLOW FOR GREAT VIEWING CONDITIONS OF THE
PERSEID`S METEOR SHOWER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
CLOUDS TO BE ON THE INCREASE THROUGH THE DAY ON MONDAY AS STRONG
SHORTWAVE TROUGH ROTATES SOUTHEAST FROM WESTERN ONTARIO INTO THE
NORTH-CENTRAL LAKES. AS THIS OCCURS...STRENGTHENING SFC LOW
PRESSURE WILL BEGIN TRACKING FROM NORTHERN MICHIGAN INTO SOUTH-
CENTRAL ONTARIO...WITH A COLD FRONT EXTENDING WELL SOUTH THROUGH
THE OHIO VLY. A RETURN OF SOUTHERLY WINDS IN ADVANCE OF BOTH
FEATURES WILL LEAD TO INCREASING MOISTURE ADVECTION THROUGH THE
DAY WITH FCST MODELS HIGHLIGHTING POSSIBLE SHOWERS/ISO STORMS
ACROSS THE WESTERN ZONES BY LATE AFTERNOON...WITH ANOTHER AREA OF
SHWRS POSSIBLE ACROSS FROM NORTHEAST PA NORTH INTO THE CATSKILLS
AS AFOREMENTIONED MARINE FRONT LIFTS NORTH TOWARDS THE REGION.
BOTH THE GFS AND NAM SHOW A SHORTWAVE MOVING ACROSS THE REGION
DURING THE AFTERNOON OFFERING A LITTLE SYNOPTIC SCALE FORCING FOR
POSSIBLE DEVELOPMENT. AS SUCH...HAVE INCREASED POPS INTO THE CHC
CATEGORY BEGINNING IN THE AFTERNOON FROM THE TWIN TIERS AND
WESTERN FINGER LAKES SOUTH...BEFORE RISING POPS FURTHER TO THE
NORTH BY THE END OF THE PERIOD. INSTABILITY LOOKS MEAGER AT BEST
ONCE AGAIN HOWEVER WITH A FEW HUNDRED JOULES POTENTIALLY
AVAILABLE...HAVE DECIDED TO OFFER AN ISOLATED THUNDER MENTION.
MAIN COLD FRONT TO SLIDE THROUGH THE AREA ON TUESDAY WITH ALL
INDICATIONS SUGGESTING THE COLD FRONT WILL BEGIN MOVING THROUGH
OUR AREA BETWEEN THE 12-15Z TIME FRAME. BEYOND THIS...FEATURE WILL
QUICKLY RACE TO THE SOUTHEAST AS MAIN EASTERN CANADIAN CLOSED LOW
RETREATS TOWARDS EASTERN QUEBEC AND TRAILING SHORTWAVE ENERGY
QUICKLY SETTLES SOUTH ACROSS OUR AREA. THUS EXPECT A GRADUAL
DECREASE IN SHWRS/ISO STORMS THROUGH THE EVENING WITH DRY BUT COOL
CONDITIONS THEN ANTICIPATED TUE NIGHT. FOR NOW...MODEL TRENDS
SUGGEST BEST INSTABILITY WILL BE EAST OF OUR REGION LENDING HOPE
THAT ANY ORGANIZED SEVERE WX WILL NOT IMPACT OUT AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
4 AM UPDATE...
MODELS CONTINUE TO SHOW A BROAD TROF ALOFT THROUGH THE EXTENDED
PERIOD WITH SFC HIGH PRESSURE IN THE VICINITY. A BEAUTIFUL STRETCH
OF WEATHER FOR LATE SUMMER WITH TEMPS GRADUALLY MODIFYING TO
SEASONAL LEVELS BY LATE IN THE PERIOD. CURRENT FORECAST IN GOOD
SHAPE JUST MINOR ADJUSTMENTS BASED ON LATEST WPC GUIDANCE.
130 PM UPDATE... FROPA WL OCCUR ON TUESDAY LEAVING THE AREA
HIGH AND DRY WITH 1020MB SFC HIGH PRESSURE BUILDING IN. ALL MED
RANGE MODELS ARE IN EXTREMELY GOOD AGREEMENT AT BOTH THE SFC AND
ALOFT. UL TROF WL PERSIST THRU THE PD WITH OCNL CLD CVR MVG THRU
BUT VRY LITTLE FRCG APPEARS PRESENT AT THIS TIME THRU THE END OF
THE WEEK. HIGH PRESSURE WL BUILD OFF THE EAST COAST ON SATURDAY
WITH THE RETURN OF WARMER TEMPS FOR THE WEEKEND. BY THE END OF THE
LONG TERM TEMPS WL CLIMB TO MORE SEASONAL VALUES.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
DENSE VALLEY FOG AT KELM WILL PERSIST UNTIL 13Z/14Z THEN LIFT.
IN GENERAL, VFR CONDITIONS WILL PERSIST THROUGH THIS TAF PERIOD
WITH FEW/SCT CU AROUND 5K FT TODAY THEN JUST SCATTERED CI OVERNIGHT.
ANOTHER VALLEY FOG EVENT IS EXPECTED TONIGHT WITH KELM DROPPING
INTO THE IFR CATEGORY AROUND 09Z.
LIGHT WINDS BECOMING NORTHWEST 5-10 KNOTS THEN LIGHT AGAIN THIS EVENING.
OUTLOOK...
MON...MAINLY VFR.
MON NGT/TUE...MVFR IN SHRA/TSRA.
WED...MAINLY VFR.
THU...VFR...IFR PSBL IN AM AT KELM FROM FG/BR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/MLJ
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
200 PM EDT SUN AUG 11 2013
.SYNOPSIS...
A SURFACE TROUGH WILL LINGER OVER THE CAROLINAS AND MIDDLE ATLANTIC
REGION THROUGH TUESDAY. A COLD FRONT WILL THEN CROSS OUR AREA
TUESDAY NIGHT...AND REMAIN STALLED ALONG THE COAST THROUGH THE REST
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM SUNDAY...
THE PATTERN WILL REMAIN RATHER PERSISTENT THROUGH THE NEAR TERM...
WITH ADDITIONAL SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON
AND EVENING. REGIONAL RADAR SHOWS SHOWERS AND THUNDERSTORMS JUST TO
OUR WEST ACROSS THE FOOTHILLS...AND THESE ARE EXPECTED TO CONTINUE
MOVING EAST WITH NEW DEVELOPMENT EASTWARD ON OUTFLOW BOUNDARIES.
ALSO NOTED A WEAK/SHEARED SHORT WAVE EMBEDDED IN THE MID LEVEL FLOW
CURRENTLY MOVING ACROSS THE MOUNTAINS. THIS FEATURE MAY PROVIDE SOME
ADDITIONAL SUPPORT FOR THE ONGOING ACTIVITY. LATEST OBSERVED
CONVECTIVE PARAMETERS ARE SIMILAR TO YESTERDAY...SO IN TERMS OF
IMPACTS...TODAYS THUNDERSTORMS WILL ONCE AGAIN BE CAPABLE OF MAINLY
BRIEF INTENSE DOWNPOURS AND FREQUENT TO EXCESSIVE-AT-TIMES CG
LIGHTNING. STILL CAN`T RULE OUT A COUPLE ISOLATED DAMAGING WIND
GUSTS...ALTHOUGH ITS WORTH NOTING THAT THE LATEST DCAPE VALUES
ACROSS ALL OF CENTRAL NC ARE BELOW 600 J/KG...WITH THE RAP SHOWING
LITTLE INCREASE THROUGH THE AFTERNOON.
ACTIVITY SHOULD WIND DOWN BY MIDNIGHT...WITH PC SKIES THE REST OF
THE NIGHT AND SOME PATCHY FOG...PARTICULARLY NEAR AREAS THAT RECEIVE
HEAVIER RAIN THIS AFTERNOON. LOWS TONIGHT WILL BE SIMILAR TO PREV
NIGHTS...LOWER 70S.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 200 PM SUNDAY...
IN THE BIG PICTURE...THE L/W TROUGH OVER NE NORTH AMERICA WILL BEGIN
TO DEEPEN SOUTHWARD AS A S/W TROUGH EMBEDDED WITHIN THE L/W TROUGH
MOVES SOUTH ACROSS THE GREAT LAKES. FOR OUR AREA...FORECAST
SOUNDINGS SHOW SUBTLE DRYING IN THE WAKE OF THE OF THE WEAK S/W
TROUGH THAT WILL CROSS OUR AREA LATER TODAY. HOWEVER...WITH PWAT
STILL PROGGED TO REMAIN AT OR SLIGHTLY ABOVE 1.75 INCHES...LITTLE
OVERALL CHANGE IN THE CONVECTIVE PARAMETERS FROM TODAY...AND THE
PIEDMONT TROUGH PROVIDING LOW LEVEL SUPPORT...LOOK FOR ADDITIONAL
SCATTERED AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS...
WITH THE MAIN IMPACTS ONCE AGAIN BEING DOWNPOURS...CG LIGHTNING...
AND PERHAPS AN ISOLD DAMAGING WIND GUST OR TWO. ITS WORTH NOTING
THAT MOST CAMS SHOW LESS COVERAGE OF THIS ACTIVITY COMPARED TO
TODAY...PERHAPS A RESULT OF THE SUBTLE DRYING AND LIMITED LARGE
SCALE SUPPORT. GIVEN SLIGHTLY LOWER HEIGHTS AND SUBSEQUENT THICKNESS
VALUES...HIGHS ON MONDAY SHOULD BE A DEGREE TO TWO LOWER THAN
TODAY...STILL AROUND 90 FOR MOST PLACES ALONG WITH PLENTY OF
HUMIDITY. THE HIGHEST HEAT INDEX VALUES IN OUR CWA WILL BE IN THE
UPPER 90S ACROSS OUR SE ZONES WHERE SFC DWPTS WILL BE THE HIGHEST.
MONDAY NIGHT...A WEAK S/W TROUGH IN THE SW FLOW IS PROGGED TO MOVE
ACROSS THE MID ATLANTIC REGION. THE SYNOPTIC SCALE MODELS ARE MORE
AGGRESSIVE WITH PRECIP/QPF AS A RESULT OF THIS SYSTEM...WHILE MANY
OF THE CAMS ARE LESS ENTHUSIASTIC FOR MUCH PRECIP ACROSS OUR AREA...
LIKELY THE RESULT OF LOSS OF DAYTIME HEATING. SINCE THERE WILL BE
SOME SYNOPTIC FORCING IN THE AREA...PREFER TO KEEP AT LEAST A SLIGHT
CHANCE POP ACROSS OUR ZONES DURING THIS TIME. LOWS ONCE AGAIN IN THE
LOWER 70S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 200 PM SUNDAY...
THE LONG TERM FORECAST IS STILL ON TRACK FOR A VERY WET PERIOD FROM
TUESDAY THROUGH SUNDAY WITH A FRONTAL ZONE STALLING OUT OVER THE
AREA AS MULTIPLE SHORTWAVES PROGRESS ALONG IT. 6Z GEFS ANOMALIES
SHOW PRECIPITABLE WATER VALUES 2-3 STANDARD DEVIATIONS ABOVE NORMAL
IN THE SOUTHERN PORTION OF THE AREA WITH RAW VALUES OF 2-2.5 INCHES
THROUGH MUCH OF THE LONG TERM. COMPETING FOR NOTORIETY WILL BE HIGH
TEMPERATURES...THURSDAY IN PARTICULAR...WHEN HIGHS IN THE TRIAD
COULD BE ONLY IN THE LOW TO MID 70S. BOTH THE ECMWF AND GFS ARE
SHOWING THICKNESS VALUES IN THE HIGH 1360S WHICH CORRESPONDS TO
NORMAL VALUES FOR EARLY MAY...NOT EARLY AUGUST. THE LARGEST SEVERE
THREAT DURING THIS PERIOD WILL BE FLOODING AS WPC IS STILL SHOWING 7
DAY TOTALS 2.5-3 INCHES IN THE TRIAD...3-4 INCHES IN THE
TRIANGLE...AND 5 PLUS ON THE COAST.
FOR TUESDAY THE FRONT IS PROGGED TO SET UP OVER UPSTATE SOUTH
CAROLINA AND THE COASTAL PLAIN OF NORTH CAROLINA. FORECAST SOUNDINGS
IN BUFKIT SHOW A SETUP SIMILAR TO THE LAST COUPLE OF DAYS WITH GOOD
INSTABILITY ALONG WITH MODERATE SHEAR VALUES...LEADING TO MOST
LIKELY MULTICELLULAR OR BROKEN LINE TYPE CONVECTION. BY
WEDNESDAY...WITH THE FRONTAL STILL PARKED TO THE SOUTH...THE SURFACE
HIGH BEGINS TO MOVE EASTWARD...BEGINNING TO DEVELOP THE WEDGE AS.
INSTABILITY CRASHES BUT SHEAR INCREASES TO 40-50 KNOTS. SOUNDINGS
BECOME VERY SATURATED IN THE LOW LEVELS AS WARM RAIN PROCESSES
BECOME DOMINANT. ANAFRONTAL RAIN WILL SPREAD NORTHWARD THROUGH NC
AND INTO SOUTHERN VA BY WEDNESDAY EVENING. SURFACE TEMPERATURES WILL
COOL IN RESPONSE TO CLOUD COVER AND THE NORTHEASTERLY SURFACE WINDS
BROUGHT ON BY THE FORMATION OF THE WEDGE FRONT. THIS GENERAL PATTERN
CONTINUES THROUGH THE DAY ON THURSDAY. AN ADDED PUNCH TO THE
RAINFALL TOTALS ON THURSDAY COULD BE PROVIDED BY A MESO-LOW MOVING
UP FROM GEORGIA THROUGH SOUTH CAROLINA AND INTO OUR CWA FROM THE
SOUTHWEST.
ON FRIDAY...THE SOUNDINGS DRY OUT A LITTLE BIT...AS THE MESO-LOW
EXITS TO THE NORTHEAST...TAKING A LOT OF MOISTURE WITH IT. A SMALL
SURFACE HIGH TRIES TO FORM OVER THE CAROLINAS AND MID-LEVEL DRY AIR
WILL EVENTUALLY WORK DOWN TO THE SURFACE ALTHOUGH SUFFICIENT MID AND
UPPER LEVEL SATURATION WILL KEEP IT CLOUDY THROUGH SATURDAY NIGHT.
PRECIPITATION CHANCES WILL BE BEST ALONG THE COAST AS AN INVERTED
TROUGH SETS UP OVER THE COAST. MUCH FURTHER SOUTH IN THE GULF OF
MEXICO...THE GFS SPINS UP A TROPICAL SYSTEM WHICH HEADS FOR MOBILE
BAY...BUT THIS FEATURE HAS NOT YET APPEARED IN THE ECMWF.
LOW LEVEL MOISTENING BEGINS AGAIN ON SUNDAY WITH THE RETURN OF
RAILROAD TRACK SOUNDINGS AND AT LEAST SOME LOW LEVEL INSTABILITY
AHEAD OF WHAT MAY OR MAY NOT BE A TROPICAL SYSTEM MOVING INTO
ALABAMA. REGARDLESS OF WHAT IT IS...THE LOW PRESSURE SYSTEM COUPLED
WITH THE HIGH OFF THE COAST WILL FUNNEL EVEN MORE MOISTURE INTO THE
CAROLINAS FOR SUNDAY AND BEYOND INTO THE WORK WEEK.
TEMPERATURES WILL SHOW A COOLING TREND EARLY IN THE LONG TERM WITH
UPPER 80S ON TUESDAY CRASHING TO THE LOW 80S BY WEDNESDAY AND DOWN
INTO THE MID TO UPPER 70S...AT LEAST IN THE NW...THURSDAY AND FRIDAY
BEFORE REBOUNDING BACK INTO THE LOW 80S IN MOST PLACES BY SUNDAY.
EXPECT LOWS IN THE UPPER 60S TO LOW 70S EARLY ON FOLLOWED BY LOW TO
MID 60S LATE IN THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1255 PM SUNDAY...
SIMILAR TO YESTERDAY...SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ACROSS CENTRAL NC AROUND 18Z. STORMS MAY BRIEFLY
REDUCE CIGS AND VSBY TO IFR CONDITIONS...ALONG WITH ISOLD 30-40 KT
WIND GUSTS. OUTSIDE OF TSTM ACTIVITY...EXPECTED VFR CONDITIONS
THROUGH THIS EVENING. LATER TONIGHT...SOME PATCHY FOG MAY REDUCE
VSBY TO 1-3 MILES...HOWEVER THIS IS MOST LIKELY TO OCCUR NEAR
LOCATIONS THAT RECEIVE HEAVIER RAINFALL THIS AFTERNOON. AFT 12/13Z
AND THROUGH THE REST OF THE TAF PERIOD...EXPECT VFR CONDITIONS AFTER
FOG BURNS OFF.
LOOKING AHEAD:
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS...AND
PATCHY MORNING FOG AND/OR LOW STRATUS WHERE STORMS OCCUR THE DAY
BEFORE...ARE EXPECTED THROUGH TUE NIGHT. THEN A MORE ACTIVE AND WET
PERIOD OF WEATHER MAY OCCUR DURING THE MID-LATE PORTION OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NP
NEAR TERM...NP
SHORT TERM..NP
LONG TERM...RTE
AVIATION...NP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
132 AM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 132 AM CDT SUN AUG 11 2013
SURFACE HIGH PRESSURE BUILDING SOUTH INTO NORTHERN NORTH DAKOTA
LATE TONIGHT...ADVECTING DRIER AIR SOUTH INTO THE REGION. THIS HAS
PRETTY MUCH ENDED ALL PRECIPITATION OVER THE CWA WITH THE
EXCEPTION OF A FEW LINGERING SHOWERS OVER MY SOUTHEAST.
MAIN CONCERN SHIFTS TO FOG DEVELOPMENT EARLY THIS MORNING ACROSS
THE NORTH AND EVENTUALLY SOUTHWARD AS SKIES TREND CLEAR. CROSBY
HAS REPORTED ZERO...WITH DEWPOINT DEPRESSIONS ELSEWHERE NEARING
OR AT ZERO. A DENSE FOG ADVISORY IS NOT OUT OF THE QUESTION BUT
WILL HOLD OFF FOR NOW WITH ONLY A FEW OBS COMING IN AT LESS THAN
ONE MILE.
UPDATE ISSUED AT 1015 PM CDT SAT AUG 10 2013
STRONG THUNDERSTORMS HAVE EXITED SOUTHWESTERN NORTH DAKOTA.
AN AREA OF SHOWERS WITH ISOLATED THUNDERSTORMS WILL CONTINUE TO
MOVE SOUTH ACROSS SOUTHWESTERN AND SOUTH CENTRAL NORTH DAKOTA
THROUGH THE OVERNIGHT HOURS. THIS SHOULD PRODUCE AN ADDITIONAL ONE
TENTH TO ONE QUARTER INCH OF PRECIPITATION OVER THE AFFECTED AREAS.
THE ONLY UPDATE TO THE FORECAST WAS TO REMOVE FIRST PERIOD POPS
FROM THE EASTERN ZONES AS DRIER AIR FILTERS IN FROM THE NORTH. THE
REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED GRIDDED
AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 715 PM CDT SAT AUG 10 2013
NUMEROUS THUNDERSTORMS WEST OF THE MISSOURI RIVER HAVE LOST
THEIR SEVERE CHARACTERISTICS WITHIN THE PAST HOUR WITH THE LOSS OF
DAYTIME HEATING. THUNDERSTORMS COULD BE STRONG AT TIMES DURING THE
NEXT HOUR OR SO. HOWEVER...A CONTINUED DOWNWARD TREND IN INTENSITY
IS EXPECTED TO CONTINUE WITH DECREASING CAPE.
THE 22Z HRRR PROGS THIS AREA OF CONVECTION TO CONTINUE TO PUSH
SOUTH ACROSS SOUTHWESTERN AND SOUTH CENTRAL NORTH DAKOTA THIS
EVENING. IT SHOULD CONTINUE WEAKEN AND MOVE OUT OF THE BISMARCK
CWA BY 09Z. UPDATED HOURLY POPS BASED ON THE LATEST RUN OF THE HRRR.
FURTHERMORE...HEAVY RAINFALL REPORTS OF ONE TO THREE INCHES IN SPOTS
WILL ADD TO RESIDUAL LOW LEVEL MOISTURE OVER WESTERN NORTH DAKOTA.
THE LATEST SHORT RANGE MODEL GUIDANCE PROGS THE CENTER OF A
SURFACE ANTICYCLONE TO SETTLE OVER NORTHWESTERN NORTH DAKOTA BY
EARLY SUNDAY MORNING. THE COMBINATION OF LIGHT WINDS AND RESIDUAL
LOW-LEVEL MOISTURE SHOULD ALLOW FOR AREAS OF FOG TO DEVELOP OVER
NORTHWESTERN NORTH DAKOTA...WITH PATCHY FOG POSSIBLE OVER
SOUTHWESTERN NORTH DAKOTA. UPDATED THE FORECAST TO REFLECT THIS
LINE OF REASONING.
THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
THE MAIN FORECAST CONCERN IN THE SHORT TERM PERIOD IS CONVECTIVE
TRENDS AND MARGINAL SEVERE POTENTIAL THROUGH TONIGHT. LATEST HI-
RES WRF/HRRR MODEL RUNS POINT TO POTENTIAL FOR STRONG STORMS
CONTINUING TO SPREAD INTO THE WEST THIS AFTERNOON/EVENING...SUPPORTED
BY A DECENT SHORT WAVE TROUGH CURRENTLY IN SOUTHERN
SASKATCHEWAN...AND ANOTHER IMPULSE IN CENTRAL MONTANA. MUCAPES AOA
1000 J/KG AND MARGINAL DEEP LAYER SHEAR SUGGEST AN ISOLATED STORM
OR TWO CAPABLE OF QUARTER SIZE HAIL. INVERTED V BUFR SOUNDINGS
ALSO INDICATE SOME GUSTY WIND POTENTIAL WITH STORM DOWNDRAFTS. STORMS
IN FAR NORTHEAST MONTANA HAVE ALREADY PRODUCED SOME HAIL UP TO
PENNY SIZE IN ROOSEVELT COUNTY. ALSO THINKING THE SHORTWAVE WILL
SUSTAIN SHOWERS AND STORMS INTO CENTRAL AND SOUTHEAST COUNTIES
AFTER DARK. LOOKING AHEAD...ISOLATED STORMS WILL AGAIN BE POSSIBLE
SUNDAY AFTERNOON IN THE EXTREME SOUTHWEST WITH THE ARRIVAL OF
ANOTHER PIECE OF MID-LEVEL ENERGY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE INTERMITTENT PRECIP CHANCES THROUGH
THE PERIOD. GFS/ECMWF/GEM/ENSEMBLES ARE ALL IN GOOD AGREEMENT WITH
OVERALL PATTERN THROUGH THE EXTENDED. UPPER LEVEL PATTERN WILL
CONSIST OF WESTERN N AMERICAN RIDGE IN PLACE WITH EASTERN N
AMERICAN TROUGH. THIS PLACES THE NORTHERN PLAINS IN NORTHWEST FLOW
WITH OCCASIONAL DISTURBANCES MOVING ACROSS THE REGION...SUPPORTING
INTERMITTENT CHANCES OF PRECIPITATION. BEST CHANCES FOR PRECIP
WILL BE ACROSS SOUTHWEST PORTION OF THE STATE...CLOSER TO BEST
INSTABILITY. 00Z ECMWF SHOWS A BETTER DEFINED SHORTWAVE IN
NORTHWEST FLOW ON THURSDAY. FOR NOW...WILL CONTINUE TO CARRY SMALL
POCKET OF CHANCE POPS ASSOCIATED WITH THIS FEATURE INTO CENTRAL
NORTH DAKOTA THURSDAY...BUT OTHERWISE ANY PRECIP CHANCES REMAIN
RELATIVELY LOW IN THE SLIGHT CHANCE CATEGORY.
WITH REGARD TO TEMPERATURES...MAX TEMPS EARLY IN THE PERIOD SHOULD
START OUT SLIGHTLY BELOW NORMAL. NORMAL HIGH FOR BIS IS 85 FOR THE
NEXT SEVERAL DAYS. AS RIDGE AXIS OVER THE WEST NUDGES EASTWARD
SLIGHTLY...WE SHOULD SEE TEMPS BACK TO THE LOW 80S BY MID WEEK.
SLIGHT DIFFERENCES IN MODEL SOLUTIONS BY NEXT SATURDAY BUT
GFS/ECMWF/ENSEMBLES SUPPORT RIDGE AXIS OVER OR JUST TO THE WEST OF
ND WHICH WOULD SUPPORT ABOVE NORMAL TEMPS. 12Z MOS GUIDANCE GIVES
BIS A HIGH OF 92 NEXT SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 132 AM CDT SUN AUG 11 2013
MAIN AVIATION CONCERN WILL BE POSSIBLE FOG/LOW STRATUS DEVELOPMENT
ACROSS THE NORTH AND JAMES RIVER VALLEY NOW THROUGH 15Z SUNDAY
MORNING. OTHERWISE EXPECT VFR THROUGH THE REMAINDER OF THE PERIOD.
MAY SEE AN ISOLATED THUNDERSTORM THIS AFTERNOON/EVENING AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
LONG TERM...JNS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1044 PM EDT MON AUG 12 2013
.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCES LATE TODAY AND OVERNIGHT. COLD FRONT
PASSES DURING THE DAY ON TUESDAY. COOLER AND DRIER...FRESHER AIR
WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
1030 PM UPDATE...
TWEAKED POPS BASED ON NEW NAM AND HRRR TRENDS. MAY HAVE TO WORRY
ABOUT N WV OVERNIGHT WITH AN EMERGING CONSENSUS FOR GREATER
COVERAGE OF PCPN. AFTER COORDINATING WITH SURROUNDING
OFFICES THOUGH...ELECTED TO HOLD OFF ON WATCH ATTM AND MENTION ISO
IN HWO. IT WILL TAKE 1.5 TO 2 INCHES IN AN HR TO CAUSE WATER
CONCERNS.
830 PM UPDATE...
MDLS...AS HAS BEEN THE CASE PAST SEVERAL DAYS...NOT DOING WELL
WITH DETAILS. HAD ONE DISTURBANCE TRACK ACROSS THE S WITH HEAVY
CONVECTION AHEAD OF WHICH CAUSED SOME WATER PROBLEMS IN SE KY AND
SW VA. AREA IN SOMEWHAT OF A LULL FOR NOW...ALTHOUGH SE OH IS
BEGINNING TO LIGHT UP WITH AN IMPULSE UP THAT WAY. ALSO TRACKING A
VORT MAX ACROSS C KY WITH CONVECTION ONGOING WITH THAT. FEELING IS
THIS MOVES ACROSS S KY...PERHAPS CLIPPING SW VA BY 06Z.
SFC FRONT STILL WELL NW OF AREA...TAKING UNTIL 12Z TO CROSS THRU
SE OH. THERE IS AGREEMENT ON KEEPING THINGS ACTIVE ALONG THE FRONT
THRU OVERNIGHT HRS THOUGH. HRRR/RUC/NAM SEEM TO POINT TO ANOTHER
AREA OF CONVECTION BREAKING OUT AHEAD OF THE FRONT...TRACKING THRU
AREA AND INTO MTNS AFTER 09Z. EVEN THOUGH THIS SHOULD BE MOVING
ALONG...WITH PWATS REMAINING EITHER SIDE OF 2 INCHES AND GIVEN
EARLIER RAINS THIS EVE...ELECTED TO EXTEND WATCH TO 15Z. THINKING
IS THOUGH...THAT NE KY AND W WV COULD BE DROPPED SEVERAL HRS
EARLIER THOUGH BUT DID NOT WANT TO GET FANCY WITH END TIMES AT
THIS JUNCTURE. DECIDED TO HOLD FOR NOW ON ANY EXPANSION GIVEN
CURRENT FFG. THERE COULD BE SOME ISO WATER ISSUES ACROSS SE OH
NEXT FEW HRS THOUGH BEFORE THAT IMPULSE MOVES OUT. HOWEVER...WITH
GUIDANCE A BIT HIGHER UP THERE...THINK WIDESPREAD THREAT IS LOW
ATTM. WILL FOLLOW TRENDS THOUGH.
PREVIOUS DISCUSSION BELOW...
SEVERAL MID LEVEL DISTURBANCES MOVE THROUGH OVERNIGHT. 12Z NAM
SEEMS TO HANDLE THEM FAIRLY WELL SO FAR. THE FIRST VORT MAX
STREAKS UP THE OHIO RIVER THRU HTS ARND 00Z REACH TOWARD CKB BY
03Z. OF COURSE...SUPPORT IS HEAD OF IT. SO DESPITE OLDER
CONVECTIVE COMPLEX IN SRN KENTUCKY TODAY...NEWER SHOWERS AND
THUNDERSTORMS HAVE FORMED ON THE NORTHERN EDGE OF THAT COMPLEX AND
WILL MOVE INTO THE TRI STATE AND SOUTHERN COUNTIES FOR LATE THIS
AFTERNOON. MORE 500 MB VORT MAXES SEEM TO HANG OVER CENTRAL AND
SOUTHERN WEST VIRGINIA AT 06Z TUESDAY.
BASING OUR FORECAST ON SURFACE FRONT NOT REACHING OUR NW COUNTIES OF
SOUTHEAST OHIO AROUND 12Z...THEN CKB-CRW LINE AROUND 18Z TUESDAY.
PLENTY OF LOW CLOUDS AND SHOWERS SHOULD BE ASSOCIATED AHEAD OF THE
FRONT...WITH THE LOWER CLOUDS LINGERING OVER THE MOUNTAINOUS
COUNTIES THROUGH LATE AFTERNOON...WHILE LIFTING IN THE OHIO VALLEY.
ISSUED FLASH FLOOD WATCH FOR SOUTHERN CWA...WILL CONTINUE TO MONITOR
RADAR TRENDS IN CASE EXTENSION/EXPANSION IS NEEDED.
NO BIG CHANGES ON TEMPERATURES AND DEW POINTS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
COLD FRONT WILL BE THROUGH THE CWA TO START THE SHORT TERM...WITH
FRESHER AIR BEGINNING TO FILTER IN ON NORTHERLY FLOW.
HOWEVER...HANGING ON TO SOME SLIGHT CHANCE TO CHANCE SHOWERS TUESDAY
NIGHT IN THE MID/UPPER LEVEL COLD AIR ADVECTION AND MOISTURE BACKED
UP AGAINST THE MOUNTAINS. ALSO HAVE TAIL OF A VORT MAX SLIDING
THROUGH BETWEEN 00Z AND 06Z WED. MAY EVEN NEED TO LINGER SOME LOW
POPS LONGER...DEPENDING HOW LONG IT TAKES TO SCOUR OUT THAT BACKED
UP MOISTURE IN THE MOUNTAINOUS COUNTIES. SURFACE HIGH PRESSURE WILL
BUILD IN THE FROM THE NORTHWEST WEDNESDAY INTO THURSDAY...HOWEVER
WITH UPPER LEVEL TROUGH LINGERING ACROSS EASTERN CANADA...WE COULD
STILL HAVE SOME HIGH LEVEL CLOUDS STREAM THROUGH ON NW FLOW. LOWER
LEVEL FLOW TURNS E/SE ACROSS VA AND EASTERN WV BY THURSDAY
AFTERNOON...SO WILL START TO SEE LOW LEVEL MOISTURE BUILDING BACK
INTO THE MOUNTAINS LATE IN THE PERIOD.
HAVE DEWPOINTS DROPPING INTO THE LOWER 50S...UPPER 40S AT HIGHEST
ELEVATIONS...WEDNESDAY NIGHT. AFTERNOON HIGHS SHOULD BE IN THE 70S
ACROSS MOST OF THE FORECAST AREA...WITH 60S AT HIGHER ELEVATIONS.
EXPECT THURSDAY TO BE A DEGREE OR TWO WARMER THAN WEDNESDAY. LOWS
WILL BE 5-10 DEGREES BELOW NORMAL...WITH MID TO UPPER 50S ACROSS THE
LOWLANDS...AND SOME UPPER 40S SNEAKING INTO THE HIGHER
ELEVATIONS...ESPECIALLY ON WEDNESDAY NIGHT IN THE DRIEST AIR.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FOLLOWED WPC THINKING WITH SOME TWEAKS. SURFACE HIGH PRESSURE
WILL PUSH EAST ACROSS OUR NORTHERN COUNTIES THURSDAY NIGHT INTO
FRIDAY. HOWEVER...MODEL CONSENSUS SUGGESTS A FEW MID-LEVEL
SHORTWAVES MAY TRACK EAST ACROSS THE AREA DURING THIS PERIOD.
AN UPPER LEVEL LOW/TROF IS THEN EXPECTED TO DEVELOP TO OUR WEST ON
FRIDAY AND MOVE EAST LATE IN THE PERIOD.
EXPECT MAINLY DIURNAL PRECIP CHANCES WILL GIVE WAY TO BETTER CHANCES
STARTING SATURDAY...EXTENDING INTO MONDAY.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
HAVE COLD FRONT INTO SE OH BY 12Z...THEN REACHING TOWARD CKB TO
CRW 18-19Z TUESDAY.
HAVE INCREASE IN CONVECTION TONIGHT AHEAD OF SFC
FRONT...ESPECIALLY ALONG AND E OF OH RVR BY 06Z. HAVE GENERAL MVFR
CONDITIONS WITH THESE AND TEMPO IFR. OUTSIDE OF CONVECTION...MVFR
FG/HZ THIS EVE WITH SOME MVFR STRATUS ABOUT.
CONDITIONS IMPROVING WITH FROPA ON TUES ALTHOUGH MVFR CIGS MAY BE
SOMEWHAT SLOW TO LIFT UNTIL AFTN. COULD BE ADDITIONAL DEVELOPMENT
ALONG FRONT IN MTNS IN AFTN BUT ELECTED TO KEEP OUT OF TAFS AT
THIS DISTANCE DUE TO CONFIDENCE LEVEL.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: CONVECTION TIMING TO VARY. LOW LEVEL STRATUS
DECK MAY FORM SOONER POST CONVECTION OVERNIGHT. LIFTING OF STRATUS
MAY VARY A FEW HRS ON TUES.
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 TUE 08/13/13
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H M M M H M M M M H H H
HTS CONSISTENCY H H L L L L L M L L L M
BKW CONSISTENCY H H H H H H H H H H L H
EKN CONSISTENCY M M M L L M M M M M M H
PKB CONSISTENCY H M M M M H H H L L L M
CKB CONSISTENCY H H M M M M M H H H H M
AFTER 00Z WEDNESDAY...
LOW STRATUS AND SHOWERS WITH LINGERING IFR ALONG COLD
FRONT...ESPECIALLY EAST OF CKB-CRW OVER THE MOUNTAINOUS COUNTIES
18Z TUESDAY THROUGH 00Z WEDNESDAY..
IFR IN RIVER VALLEY FOG POSSIBLE IN WEST VIRGINIA...THE COOLER
TEMPERATURES 06Z TO 12Z WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR WVZ005>008-
013>016-024>027-033>037.
OH...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR OHZ086-087.
KY...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR VAZ003-004.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/30
SHORT TERM...JMV
LONG TERM...JSH
AVIATION...KTB/30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
319 PM EDT SUN AUG 11 2013
.SYNOPSIS...
STATIONARY FRONT LINGERS ACROSS THE OHIO VALLEY AND WEST VIRGINIA TONIGHT.
UPPER LEVEL DISTURBANCES MONDAY NIGHT...OLD BOUNDARY LIFT NORTH AS
A WARM FRONT. COLD FRONT TUESDAY. COOLER AND DRIER AIRMASS MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
OVERALL PATTERN REMAINS THE SAME TODAY AND ESSENTIALLY FOR ONE MORE
DAY WITH FORECAST AREA WITHIN ZONAL FLOW REGIME IN THE BASE OF
LONGWAVE UPPER TROUGH CENTERED OVER ONTARIO/QUEBEC CANADA. S/W
TROUGHS WITH ASSOC VORT MAXES CONTINUE TO PERIODICALLY MOVE ACROSS
THE AREA THROUGH THE MEAN FLOW WITH WEAK DIFFUSE SFC FRONT
CONTINUING TO MEANDER ACROSS THE NORTHERN PART OF THE AREA. OVERALL
THREAT FOR FLASH FLOODING HAS SUBSIDED BUT THE PRIMARY FORECAST
CONCERN CONTINUES TO BE THE TIMING OF VORT MAXES AND SUBSEQUENT OFF
AND ON AGAIN PRECIP CHANCES.
TOUGH TO PICK OUT THE QUASI-STATIONARY DIFFUSE SFC FRONT AT 15Z SFC
ANALYSIS WITH TEMPS ALONE. A GOOD MOISTURE GRADIENT STILL IN PLACE
ACROSS THE NORTHERN PART OF THE FORECAST AREA BUT DEWPTS HAVE RISEN
2-5 DEGREES IN THE PAST 2-3 HOURS ACROSS NW ZONES...INDICATING
PERHAPS SOME NORTHERN RETREAT TO THE FRONT. PRESSURE FIELD ALSO SEEM
TO INDICATE FRONT LOCATED ROUGHLY JUST NORTH OF PBZ SOUTHWESTWARD TO
NEAR PERRY COUNTY OH TO NEAR CINCINNATI...WITH A VERY WEAK SFC LOW
OVER SC OHIO. THIS MORNING/S ONGOING PRECIP ACROSS THE SOUTHERN
ZONES ASSOC WITH YET ANOTHER VORT MAX EXPECTED TO CONTINUE EASTWARD
AS THE VORT MAX PUSHES EAST AS WELL. LATEST RUC13 AND NAM12
DEPICTING THE NEXT RIPPLE/VORT MAX APPROACHING NW ZONES BTWN 21Z AND
00Z MON. A FEW SHOWERS ALREADY POPPING UP NEAR FRONT ACROSS NC KY
AND SW OHIO NEAR FRONTAL ZONE. WILL MOST LIKELY INCREASE PRECIP
CHANCES ACROSS THE WESTERN ZONES BY MID/LATE AFTERNOON TO CHANCE TO
ACCOUNT FOR POTENTIAL ACTIVITY PUSHING INTO THE NW ZONES. NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL WITH THIS ACTIVITY BUT
A FEW OF THESE COULD BE ON THE STRONGER SIDE. MEANWHILE ALSO EXPECT
SHOWERS AND THUNDERSTORMS TO CONTINUE TO INCREASE IN COVERAGE OVER
SOUTHERN AND SOUTHEAST ZONES WHERE BETTER DEEP LAYER MOISTURE
CONTINUES TO RESIDE.
OVERNIGHT ANY ONGOING CONVECTION SHOULD DISSIPATE RAPIDLY WITH THE
LOSS OF DAYTIME HEATING...WITH THE CONVECTION NO LONGER TIED TO THE
SFC FRONT WHICH IS PROGGED TO REMAIN WEST WITH THE APPROACH OF A SFC
LOW OVER SOUTHERN GREAT LAKES. EXPECT LOWLANDS TO BE DRY BY 06Z
MON...AND REMOVED POPS FOR ALL LOCATIONS BY 09Z MON. CLOUDS WHICH
WILL INITIALLY ATTEMPT TO SCATTER INTO A MOSTLY CLEAR TO PARTLY
CLOUDY SKY EARLY ON MAY REFORM INTO A LOW STRATUS DECK...PARTICULARLY
OVER THE WV LOWLANDS WHERE DEWPOINTS REMAIN RELATIVELY HIGH...WITH
NAM12 BUFKIT SOUNDINGS INDICATING COMPLETE SATURATION UP TO AROUND
700FT AGL WITH SLIGHTLY STRONGER WINDS AT 925MB CREATING SOME
OVERTURNING. RECENT RUC13 SOUNDING LESS ROBUST ON THIS SATURATED
LAYER...SO STRATUS DECK STILL SOMEWHAT IN QUESTION. EITHER
WAY...STILL EXPECT THE USUAL VALLEY FOG AND HAZE AS WELL.
MONDAY...THE AREA STARTS OFF DRY WITH INITIAL ZONAL FLOW. HOWEVER AS
HAS BEEN THE CASE AS OF LATE...FLOW QUICKLY RETURNS TO THE W/SW BY
18Z MON AS THE NEXT S/W TROUGH AND VORT MAX QUICKLY DIVES AROUND THE
BASE OF THE LONGWAVE TROUGH INTO THE LOWER AND MID OHIO RIVER VALLEY
DURING THE AFTERNOON HOURS. EARLY MORNING CLOUDS IN PLACE SHOULD
SLOWLY ERODE BY MID TO LATE MORNING AND LEAVE BEHIND A GENERALLY
PARTLY CLOUDY SKY BY EARLY AFTERNOON. WILL BRING IN SLIGHT CHANCE TO
LOW CHANCE POPS BY THE AFTERNOON HOURS FROM WEST TO EAST BUT EXPECT
THE BULK OF THE PRECIP TO HOLD OFF UNTIL THE EVENING HOURS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
GFS MODEL SHOWS A VORT MAX FEATURE...AHEAD OF A PARENT LONGWAVE
TROUGH...APPROACHING FROM THE NORTHWEST BY 00Z TUESDAY. NAM
SOLUTION BRING DEEP MOISTURE ALONG A SMALL AREA OF H6 2D
FRONTOGENESIS AROUND THE TRI STATE AREA BY 00Z TUESDAY. SOUTHWEST
FLOW INJECTS MOISTURE INTO WV MONDAY NIGHT...ALLOWING SHOWERS AND
STORMS TO DEVELOP DURING THE OVERNIGHT HOURS. A BOUNDARY LAYER
COVERGENCE ZONE IS ALSO EVIDENT LIFTING NORTH FROM 00-03Z TUESDAY
WITH PWATS AROUND 1.8 INCHES. BOTH MODELS ARE IN AGREEMENT IN
THEIR QPF FIELDS WITH THE AFOREMENTIONED SHORTWAVE.
INCREASE POPS WITH THIS WARM-FRONT- LIKE FEATURE LIFTING NORTH
LATE MONDAY NIGHT.
A PRE FRONTAL TROUGH APPROACHES FROM THE NORTHWEST...EVIDENT IN BL
CONVERGENCE FIELDS...SFC CAPE AROUND 1000 J/KG WITH A GRADIENT JUST
NORTHWEST...AND PWATS AROUND 1.75. THEREFORE...ADJUSTED POPS TO
LIKELY/CATEGORICAL WITH THE PRE-FRONTAL WAVE TUESDAY. CODED A LULL
IN POPS AFTER SECOND ROUND OF SHOWERS OR STORMS ASSOCIATED WITH
PRE FRONTAL TROUGH...BEFORE INCREASING POPS BACK TO HIGH
LIKELIES...AND EVEN CATEGORICAL OVER NORTHEAST MOUNTAINS THROUGH
EARLY TUESDAY NIGHT. FLOW TURNS FROM THE NORTH LATE TUESDAY NIGHT
AND WEDNESDAY.
RELATIVELY COOLER AND DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT
TUESDAY NIGHT WITH LINGERING CLOUDS...DECREASING CLOUDS AND POPS
FROM WEST TO EAST TUESDAY NIGHT. EXPECT PLEASANT TEMPERATURES
TUESDAY NIGHT AND WEDNESDAY WITH TEMPERATURES BELOW NORMAL.
THE FRONT CLEAR THE MOUNTAINS BY LATE TUESDAY NIGHT.
BLENDED THE BIAS CORRECTED NAM WITH SREF SOLUTIONS FOR
TEMPERATURES THROUGH THE PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE BUILDS FROM THE WEST...AS A COLD FRONT EXITS EAST OF
THE APPALACHIANS WEDNESDAY MORNING. NORTHERLY FLOW CONTINUES
THURSDAY KEEPING FRESH AND COOLER AIRMASS IN PLACE. THIS BROAD
HIGH PRESSURE WILL BRING SUBSIDENCE...CLEAR SKIES...AND COOLER
TEMPERATURES AREA EXPECTED THROUGH THE END OF THE WEEK.
FLOW BECOMES NORTHERLY EARLY WEDNESDAY THROUGH FRIDAY.
THEREFORE...HIGHS WILL STRUGGLE TO REACH THE MID TO LOWER
80S...WHILE LOWS WILL DEPEND ON EITHER SKIES CLEAR OR NOT. CLEAR
SKIES COULD ALLOW RADIATIONAL COOLING DURING THE NIGHTS...CAPABLE
TO DROP LOW TEMPERATURES INTO THE MID 50S BY THURSDAY. THE GFS
MODEL SUGGEST A SHARP H5 TROUGH APPROACHES FROM THE WEST FRIDAY
NIGHT INTO SATURDAY.
THEREFORE...ADJUSTED POPS...SKY...AND TEMPERATURES. USED THE HPC
GUIDANCE FOR TEMPERATURES AND POPS...WITH SOME TIMING TWEAKING IN
BETWEEN.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THRU 18Z MONDAY...
SHOWERS WITH A FEW THUNDERSTORMS CONTINUE THIS AFTERNOON MAINLY
ACROSS THE SOUTHERN ZONES...WITH MORE SHOWERS AND THUNDERSTORMS
OVER CENTRAL AND SW OHIO MOVING EASTWARD TOWARDS THE TRI-STATE
AREA AND SE OHIO. EXPECT MAINLY VFR CONDITIONS TO PREVAIL THIS
AFTERNOON...WITH THE EXCEPTION OF BKW WHERE MVFR CIGS SHOULD
PREVAIL WITH PERHAPS SOME INTERMITTENT VFR. SHOULD A SHOWER OR
STORM DIRECTLY IMPACT A TERMINAL...INTERMITTENT MVFR CIGS WITH
MVFR/IFR VIS WILL LIKELY RESULT WITH BRIEF HEAVY RAINFALL.
OVERNIGHT SHOWERS AND THUNDERSTORMS WILL DIMINISH IN COVERAGE AND
INTENSITY WITH MOST LOCATIONS DRY BY 06Z. FOG AND/OR LOW STRATUS
WILL LIKELY FORM AFTER 06Z AND TOWARDS THE DAWN HOURS WITH SKIES
ATTEMPTING TO SCATTER TO MOSTLY CLEAR BY 09Z ACROSS MOST LOWLAND
LOCATIONS WITH ABUNDANT LLVL MOISTURE AND RECENT RAINS. CONDITIONS
ARE EXPECTED TO IMPROVE DURING THE MORNING HOURS AS USUAL...BUT
IMPROVEMENT MAY BE A BIT SLOWER THAN NORMAL AS A POTENTIAL STOUT
LOW STRATUS DECK MAY BE A BIT STUBBORN TO SCATTER.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: REDEVELOPMENT OF CONVECTION THIS AFTERNOON
AND EVENING COULD VARY. TIMING OF ONSET FOG TONIGHT AND
IMPROVEMENT OF FLIGHT CONDITIONS EARLY MON MORNING MAY VARY.
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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M M M M M M M H H M L L
HTS CONSISTENCY M M M H H H H H H M L L
BKW CONSISTENCY H H H H M M M M M H H H
EKN CONSISTENCY H H H H H H M H H M L L
PKB CONSISTENCY H H H H H H H H H M L L
CKB CONSISTENCY H H H H H H H H H M M L
AFTER 18Z MONDAY...
IFR POSSIBLE IN FOG/LOW STRATUS MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...50
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
248 PM EDT SUN AUG 11 2013
.SYNOPSIS...
STATIONARY FRONT LINGERS ACROSS THE OHIO VALLEY THROUGH MONDAY.
UPPER LEVEL DISTURBANCE MONDAY NIGHT. COLD FRONT TUESDAY. COOLER
AND DRIER AIRMASS MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
OVERALL PATTERN REMAINS THE SAME TODAY AND ESSENTIALLY MONDAY AS
WELL FOR ONE MORE DAY WITH FORECAST AREA WITHIN ZONAL FLOW REGIME IN
THE BASE OF LONGWAVE UPPER TROUGH CENTERED OVER ONTARIO/QUEBEC
CANADA. S/W TROUGHS WITH ASSOC VORT MAXES CONTINUE TO PERIODICALLY
MOVE ACROSS THE AREA THROUGH THE MEAN FLOW WITH WEAK DIFFUSE SFC
FRONT CONTINUING TO MEANDER ACROSS THE NORTHERN PART OF THE AREA.
OVERALL THREAT FOR FLASH FLOODING HAS SUBSIDED BUT THE PRIMARY
FORECAST CONCERN CONTINUES TO BE THE TIMING OF VORT MAXES AND
SUBSEQUENT OFF AND ON AGAIN PRECIP CHANCES.
TOUGH TO PICK OUT THE QUASI-STATIONARY DIFFUSE SFC FRONT AT 15Z SFC
ANALYSIS WITH TEMPS ALONE. A GOOD MOISTURE GRADIENT STILL IN PLACE
ACROSS THE NORTHERN PART OF THE FORECAST AREA BUT DEWPTS HAVE RISEN
2-5 DEGREES IN THE PAST 2-3 HOURS ACROSS NW ZONES...INDICATING
PERHAPS SOME NORTHERN RETREAT TO THE FRONT. PRESSURE FIELD ALSO SEEM
TO INDICATE FRONT LOCATED ROUGHLY JUST NORTH OF PBZ SOUTHWESTWARD TO
NEAR PERRY COUNTY OH TO NEAR CINCINNATI...WITH A VERY WEAK SFC LOW
OVER SC OHIO. THIS MORNING/S ONGOING PRECIP ACROSS THE SOUTHERN
ZONES ASSOC WITH YET ANOTHER VORT MAX EXPECTED TO CONTINUE EASTWARD
AS THE VORT MAX PUSHES EAST AS WELL. LATEST RUC13 AND NAM12
DEPICTING THE NEXT RIPPLE/VORT MAX APPROACHING NW ZONES BTWN 21Z AND
00Z MON. A FEW SHOWERS ALREADY POPPING UP NEAR FRONT ACROSS NC KY
AND SW OHIO NEAR FRONTAL ZONE. WILL MOST LIKELY INCREASE PRECIP
CHANCES ACROSS THE WESTERN ZONES BY MID/LATE AFTERNOON TO CHANCE TO
ACCOUNT FOR POTENTIAL ACTIVITY PUSHING INTO THE NW ZONES. NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL WITH THIS ACTIVITY BUT
A FEW OF THESE COULD BE ON THE STRONGER SIDE. MEANWHILE ALSO EXPECT
SHOWERS AND THUNDERSTORMS TO CONTINUE TO INCREASE IN COVERAGE OVER
SOUTHERN AND SOUTHEAST ZONES WHERE BETTER DEEP LAYER MOISTURE
CONTINUES TO RESIDE.
OVERNIGHT ANY ONGOING CONVECTION SHOULD DISSIPATE RAPIDLY WITH THE
LOSS OF DAYTIME HEATING...WITH THE CONVECTION NO LONGER TIED TO THE
SFC FRONT WHICH IS PROGGED TO REMAIN WEST WITH THE APPROACH OF A SFC
LOW OVER SOUTHERN GREAT LAKES. EXPECT LOWLANDS TO BE DRY BY 06Z
MON...AND REMOVED POPS FOR ALL LOCATIONS BY 09Z MON. CLOUDS WHICH
WILL INITIALLY ATTEMPT TO SCATTER INTO A MOSTLY CLEAR TO PARTLY
CLOUDY SKY EARLY ON MAY REFORM INTO A LOW STRATUS DECK...PARTICULARLY
OVER THE WV LOWLANDS WHERE DEWPOINTS REMAIN RELATIVELY HIGH...WITH
NAM12 BUFKIT SOUNDINGS INDICATING COMPLETE SATURATION UP TO AROUND
700FT AGL WITH SLIGHTLY STRONGER WINDS AT 925MB CREATING SOME
OVERTURNING. RECENT RUC13 SOUNDING LESS ROBUST ON THIS SATURATED
LAYER...SO STRATUS DECK STILL SOMEWHAT IN QUESTION. EITHER
WAY...STILL EXPECT THE USUAL VALLEY FOG AND HAZE AS WELL.
MONDAY...THE AREA STARTS OFF DRY WITH INITIAL ZONAL FLOW. HOWEVER AS
HAS BEEN THE CASE AS OF LATE...FLOW QUICKLY RETURNS TO THE W/SW BY
18Z MON AS THE NEXT S/W TROUGH AND VORT MAX QUICKLY DIVES AROUND THE
BASE OF THE LONGWAVE TROUGH INTO THE LOWER AND MID OHIO RIVER VALLEY
DURING THE AFTERNOON HOURS. EARLY MORNING CLOUDS IN PLACE SHOULD
SLOWLY ERODE BY MID TO LATE MORNING AND LEAVE BEHIND A GENERALLY
PARTLY CLOUDY SKY BY EARLY AFTERNOON. WILL BRING IN SLIGHT CHANCE TO
LOW CHANCE POPS BY THE AFTERNOON HOURS FROM WEST TO EAST BUT EXPECT
THE BULK OF THE PRECIP TO HOLD OFF UNTIL THE EVENING HOURS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
MULTIPLE VORTICITY MAXIMA RIPPLE INTO THE OHIO VALLEY MONDAY AHEAD
OF A COLD FRONT MOVING INTO THE SOUTHERN GREAT LAKES. WILL GET
DECENT FRONTOGENESIS FROM THESE FEATURES...FOLLOWED NEARLY
SEAMLESSLY BY THE COLD FRONT ITSELF...PROVIDING THE MAIN SOURCE FOR
THE LIFT. LOW LEVEL FLOW BACKS TO THE SOUTHWEST...WITH A RETURN OF
THE MOISTURE FROM THE BRIEF PERIOD OF DRYING IN AND AROUND THE 850MB
LEVEL. DEEP MOISTURE AHEAD OF THE FRONT WILL BRING ROUNDS OF SHOWERS
AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY...WITH THE FRONT CLEARING
THE MOUNTAINS BY LATE TUESDAY. CLEAR THE POPS TUESDAY NIGHT.
IN THE CONVECTION...PRECIPITABLE WATER VALUES WILL RETURN TO THE
1.50 TO 1.75 INCH RANGE MONDAY...AND CLOSER TO 2.00 INCHES TUESDAY.
DO NOT ANTICIPATE MUCH IN TERMS OF A SEVERE THREAT FOR THE AREA ON
MONDAY OR TUESDAY...ALTHOUGH TUESDAY WILL SEE A LITTLE BETTER
ORGANIZATION TO THE FLOW WITH 0 TO 6 KM BULK SHEAR VECTORS IN THE 30
TO 40 KNOT RANGE.
WITH THE CLEARING OF THE COLD FRONT AND THE HUMID AIRMASS...COOLER
AND DRIER CONDITIONS COME IN FOR MID WEEK. TENDED TO UNDERCUT THE
GUIDANCE NUMBERS JUST A TOUCH GIVEN THE 850MB TEMPERATURES DROPPING
INTO THE UPPER SINGLE DIGITS CELSIUS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BY WEDNESDAY MORNING...THE COLD FRONT SHOULD BE ALREADY EAST OF
THE APPALACHIANS...LEAVING WV AND THE OH VALLEY UNDER A SURFACE
HIGH PRESSURE. CLEAR SKIES...AND COOLER TEMPERATURES AREA EXPECTED
THROUGH THE END OF THE WEEK...SINCE FLOW BECOMES NORTHERLY EARLY
WEDNESDAY THROUGH FRIDAY. THEREFORE...HIGHS WILL STRUGGLE TO REACH
THE MID TO LOWER 80S...WHILE LOWS WILL DEPEND ON EITHER SKIES
CLEAR OR NOT. CLEAR SKIES COULD ALLOW RADIATIONAL COOLING DURING
THE NIGHTS...CAPABLE TO DROP LOW TEMPERATURES INTO THE MID 50S BY
THURSDAY. THE GFS MODEL SUGGEST A SHARP H5 TROUGH APPROACHES FROM
THE WEST FRIDAY NIGHT INTO SATURDAY.
THEREFORE...ADJUSTED POPS...SKY...AND TEMPERATURES. USED THE HPC
GUIDANCE FOR TEMPERATURES AND POPS...WITH SOME TIMING TWEAKING IN
BETWEEN.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THRU 18Z MONDAY...
SHOWERS WITH A FEW THUNDERSTORMS CONTINUE THIS AFTERNOON MAINLY
ACROSS THE SOUTHERN ZONES...WITH MORE SHOWERS AND THUNDERSTORMS
OVER CENTRAL AND SW OHIO MOVING EASTWARD TOWARDS THE TRI-STATE
AREA AND SE OHIO. EXPECT MAINLY VFR CONDITIONS TO PREVAIL THIS
AFTERNOON...WITH THE EXCEPTION OF BKW WHERE MVFR CIGS SHOULD
PREVAIL WITH PERHAPS SOME INTERMITTENT VFR. SHOULD A SHOWER OR
STORM DIRECTLY IMPACT A TERMINAL...INTERMITTENT MVFR CIGS WITH
MVFR/IFR VIS WILL LIKELY RESULT WITH BRIEF HEAVY RAINFALL.
OVERNIGHT SHOWERS AND THUNDERSTORMS WILL DIMINISH IN COVERAGE AND
INTENSITY WITH MOST LOCATIONS DRY BY 06Z. FOG AND/OR LOW STRATUS
WILL LIKELY FORM AFTER 06Z AND TOWARDS THE DAWN HOURS WITH SKIES
ATTEMPTING TO SCATTER TO MOSTLY CLEAR BY 09Z ACROSS MOST LOWLAND
LOCATIONS WITH ABUNDANT LLVL MOISTURE AND RECENT RAINS. CONDITIONS
ARE EXPECTED TO IMPROVE DURING THE MORNING HOURS AS USUAL...BUT
IMPROVEMENT MAY BE A BIT SLOWER THAN NORMAL AS A POTENTIAL STOUT
LOW STRATUS DECK MAY BE A BIT STUBBORN TO SCATTER.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: REDEVELOPMENT OF CONVECTION THIS AFTERNOON
AND EVENING COULD VARY. TIMING OF ONSET FOG TONIGHT AND
IMPROVEMENT OF FLIGHT CONDITIONS EARLY MON MORNING MAY VARY.
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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M M M M M M M H H M L L
HTS CONSISTENCY M M M H H H H H H M L L
BKW CONSISTENCY H H H H M M M M M H H H
EKN CONSISTENCY H H H H H H M H H M L L
PKB CONSISTENCY H H H H H H H H H M L L
CKB CONSISTENCY H H H H H H H H H M M L
AFTER 18Z MONDAY...
IFR POSSIBLE IN FOG/LOW STRATUS MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26/50
NEAR TERM...50
SHORT TERM...26
LONG TERM...ARJ
AVIATION...50
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
442 PM EDT SUN AUG 11 2013
.SYNOPSIS...
GRADUAL UPPER-LEVEL TROUGH AMPLIFICATION IS EXPECTED EARLY THIS
WEEK OVER THE GREAT LAKES REGION AND ADJACENT OHIO VALLEY/NORTHEAST
STATES. THE MEAN UPPER TROUGHING WILL PERSIST THROUGH THE SECOND
HALF OF THE WEEK...KEEPING TEMPERATURES BELOW NORMAL. A COLD FRONT
WILL BE THE FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS AS IT
CROSSES THE REGION ON TUESDAY. CANADIAN HIGH PRESSURE WILL PROVIDE
FAIR WEATHER AND COOL/DRY CONDITIONS FROM WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
MOST OF THE MID DECK OF CLOUDS HAS EITHER MOVED EAST OR
DISSIPATED. THE LOW-LEVEL MOISTURE HAS PRODUCED BANDS OF FAIR
WEATHER CUMULUS OVER MUCH OF THE NORTHERN AND CENTRAL AREAS. RADAR
SHOWS A FEW ENHANCED ELEMENTS...WEAK SHOWERS MAINLY EAST OF ALTOONA.
THE FEW SHOWERS AND ENHANCED CLOUDS OVER THE SOUTHWEST ARE IN THE
MODEST TONGUE OF HIGHER THETA-E AIR NOISING UP FROM THE PANHANDLE
OF WV. THERE IS A LARGE SCALE THETA-E GRADIENT...WELL DEFINED AT
1000 HPA DRAPED ACROSS SOUTHEAST PA NORTH OF ALTOONA THEN WEST
INTO OHIO. BEST ISOLATED SHOWERS WILL BE IN THE SOUTHWEST IN THAT
SLIVER OF HIGH THETA-E AIR.
SHOULD BE QUITE COMFORTABLE THROUGH THIS EVENING WITH TEMPERATURES
RANGING 70 TO LOWER 80S IN SOUTHEAST AND DEW POINTS MAINLY IN
UPPER 40 TO MID 60S.
OVERNIGHT MODELS AND HIGH RESOLUTION MODELS SHOW ISOLATED
CONVECTION AND NO ORGANIZATION. THE 4KM NAM ACTUALLY DEVELOPS A
SMALL MCS...PROBABLY OUT OF THE WAVES OVER MICHIGAN THIS
AFTERNOON...AND BRINGS THE SYSTEM INTO WESTERN PA BY 0500 UTC AND
WEAKENS IT AS IT MOVES INTO SE PA AND DIES A SLOW DEATH NEAR
HARRISBURG. SO KEPT POPS MAINLY SLIGHT CHANCE AFTER MIDNIGHT.
THE RAP AND 4KM NAM PULL SOME OF THE WARMER AIR NORTHWARD TONIGHT
AND THE BOUNDARY GETS INTO N-CENTRAL PA. BEST CHANCE WOULD BE
ALONG AND SOUTH OF BOUNDARY IN MODELS AND BEST FORCING AFTER 0600
UTC WOULD BE SW PA.
OVERNIGHT LOWS MAINLY UPPER MID-50S TO MID 60S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
SREF/GEFS FROM 15 AND 12 UTC SEEM TO SHOW LIGHT RAIN AMOUNTS WHICH
THIS TIME OF YEAR SHOW A WET BIAS. WILL BE WARMER AND MOISTURE
MONDAY SO CANNOT RULE OUT SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. BUT NOTHING IMPLIES A BIG RAIN POTENTIAL AS PW
VALUES ARE STILL LOW.
PREVIOUS DISCUSSION:
SOME CLOUDS/SPOTTY LGT SHOWERS MAY BE LINGERING OVR ERN
SXNS PER MDL CONS EARLY TOMORROW. THE SFC-850MB FLOW WILL SHIFT TO
THE WSW AHEAD OF POLAR FRONT PUSHING SEWD FROM THE GRT LKS REGION.
GRADUAL HGT FALLS ARE EXPECTED TO OCCUR IN ASSOCIATION WITH
UPPER TROUGH DIGGING SEWD ACRS NRN ONTARIO INTO NW QUEBEC...WITH
INCREASINGLY STRONG CYCLONIC UPPER FLOW OVERSPREADING THE GRT LKS
REGION AND ADJACENT OH VLY. THE BEST LLVL MSTR FLUX AND CAPE IS
PROGGED IMMEDIATELY AHEAD OF THE COLD FRONT OVER PORTIONS OF THE
MIDWEST/LWR LKS/UPPER OH VLY DURING THE AFTN...WITH TSTMS EXPECTED
TO INCREASE/INTENSIFY AS BLYR DESTABILIZES. NOT EXPECTING OUR AREA
TO BE IMPACTED UNTL LATER AROUND MID/LATE EVE...AS STORMS SPREAD
SEWD. THE DAY 2 SEE TEXT/5 PCT SVR PROBS INCLUDE THE NW AND NCNTRL
ZONES...HOWEVER ANY STORMS THAT REACH THIS AREA SHOULD BE OF A
WEAKENING CONVECTIVE INTENSITY.
WILL KEEP SCHC POPS FOR THE DAYTIME HOWEVER EXPECT ANY CONVECTION
TO BE ISOLD AT BEST. HIGHEST POPS /LKLY CATG OR 60-70 PCT/ ARE
OVER THE NW ZONES TOMORROW NIGHT. PRE-FRONTAL WSWLY FLOW SHOULD
ALLOW TEMPS TO CLIMB A FEW TO SEVERAL DEGS WARMER THAN TODAY WITH
HIGHS RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
GENERALLY COSMETIC CHANGES MADE TO PREVIOUS EXTENDED FORECAST
TODAY AS PATTERN WILL BE DOMINATED BY THE ROCKY MOUNTAIN UPPER
RIDGE AND DOWNSTREAM LONG WAVE TROF FROM EASTERN CANADA TO THE MID
ATLANTIC REGION THIS WEEK.
BEST CHANCE OF PRECIPITATION WILL COME FROM A FRONTAL SYSTEM
MONDAY NIGHT AND TUESDAY BEFORE THE MEAN UPPER TROF AXIS SETTLES
EAST OF THE AREA FOR THE LATTER HALF OF THIS WEEK. AS PREVIOUSLY
MENTIONED...THE BIGGEST IMPACT WILL BE A FRESH SHOT OF DRIER AND
COOLER AIR FOR THE MIDDLE OF THE WEEK AS TEMPERATURES DROP BELOW
AVERAGE ON WED AND THU. FLOW BEGINS TO TURN SW LATE IN THE PERIOD
FOR SOME MODERATION AS THE WEEKEND APPROACHES.
LATE IN THE PERIOD...WESTERN ATLANTIC UPPER RIDGE RETROGRADES AND
AMPLIFIES OVER BERMUDA. THIS WILL HELP TO SHARPEN THE EAST COAST
TROF AXIS AND DIRECT DEEPER LAYER MOISTURE NORTHWARD INTO THE MID
ATLANTIC REGION NEXT WEEKEND. HAVE INTRODUCED SHOWER CHANCES AS A
RESULT...MAINLY ON SUNDAY. GULF COAST TROPICAL DEVELOPMENT IS
POSSIBLE WITH THIS SURGE OF MOISTURE...SO WE`LL BE WATCHING THIS
WITH INTEREST AS THE WEEK PROGRESSES.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
VFR CONDS WILL PREVAIL THRU THE AFTN. COSPA DATA SUGGESTS AN
ISOLD SHOWER/TSTM IS PSBL OVER THE SCNTRL TERMINALS...BUT
PROBABILITY/COVERAGE IS TOO LOW TO INCLUDE IN TAFS ATTM. SOME LOW
CLOUDS AND FOG ARE PSBL TNT INTO MONDAY MORNING...AND HAVE ADDED
BR/VCFG AND RESTRICTED VIS WITH THE 18Z ISSUANCE. CONFIDENCE IN
IFR IS MEDIUM GIVEN FAIRLY GOOD AGREEMENT AMONGST THE GUIDANCE.
WILL MAINTAIN REGULAR TAF AT BFD USING TOTAL OB CONCEPT...AND THE
FACT THAT THERE IS NO SIG WX. IF THE OUTAGE CONTINUES INTO TONIGHT
LATER ISSUANCES MAY INCLUDE AMD NOT SKED GIVEN THE PROSPECT OF FOG
AND LOW CIGS OVERNIGHT.
OUTLOOK...
MON...VFR. SHOWERS/TSTMS LKLY OVER THE NW AIRFIELDS MON NGT.
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...ROSS/DEVOIR
AVIATION...STEINBUGL
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
746 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730AM UPDATE...MINOR CHANGES TO NEAR TERM FCST FOR THE EARLY
MORNING UPDATE. IR/VIS SATL SHOWS BAND OF MID LVL CLOUDS STREAKING
EWD ALONG THE I-80 CORRIDOR...WITH SOME ISOLD SPRINKLES /LKLY NOT
MEASURABLE PCPN/ SHOWING UP ON RADAR. CLEARING TO THE NORTH ALONG
THE PA/NY BORDER HAS LEAD TO RIVER/STREAM VALLEY FOG. SOME FOG
ALSO INDICATED VIA SATL ACRS THE SCENTRL MTNS WHERE SKIES ARE ALSO
M/CLR.
PREVIOUS DISCUSSION...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN
DURING THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING
MUCH QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH
SHOT OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS
TEMPERATURES AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS
TO TURN SW LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND
APPROACHES. QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA
AND PLENTY OF SUN.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MAIN CHANGE AT 12Z IS THE BFD OB...NOTAM ISSUED...ET
STAFF LOOKING INTO ISSUE...UNABLE TO DIAL INTO SITE.
DUJ HAD A SHOWER. AS WAS THE CASE YESTERDAY...SOME SHOWERS
ON THE RADAR. I WAS THINKING THAT ANY SHOWERS WOULD BE ALONG
THE MD LINE...NOT UP BY I-80. STILL EXPECT THESE TO BE AWAY
FROM OUR TAF SITES.
A LOT OF CLDS...SO TOOK FOG OUT OF THE 06Z PACKAGE...BUT
A LITTLE FOG HERE AND THERE...BEEN ADJUSTING THE FCST FOR
THIS.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS/STEINBUGL
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
658 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN
DURING THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING
MUCH QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH
SHOT OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS
TEMPERATURES AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS
TO TURN SW LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND
APPROACHES. QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA
AND PLENTY OF SUN.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MAIN CHANGE AT 12Z IS THE BFD OB...NOTAM ISSUED...ET
STAFF LOOKING INTO ISSUE...UNABLE TO DIAL INTO SITE.
DUJ HAD A SHOWER. AS WAS THE CASE YESTERDAY...SOME SHOWERS
ON THE RADAR. I WAS THINKING THAT ANY SHOWERS WOULD BE ALONG
THE MD LINE...NOT UP BY I-80. STILL EXPECT THESE TO BE AWAY
FROM OUR TAF SITES.
A LOT OF CLDS...SO TOOK FOG OUT OF THE 06Z PACKAGE...BUT
A LITTLE FOG HERE AND THERE...BEEN ADJUSTING THE FCST FOR
THIS.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
537 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN
DURING THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING
MUCH QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH
SHOT OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS
TEMPERATURES AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS
TO TURN SW LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND
APPROACHES. QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA
AND PLENTY OF SUN.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
AS WAS THE CASE YESTERDAY...SOME SHOWERS ON THE RADAR.
I WAS THINKING THAT ANY SHOWERS WOULD BE ALONG THE MD
LINE...NOT UP BY I-80. STILL EXPECT THESE TO BE AWAY FROM
OUR TAF SITES.
A LOT OF CLDS...SO TOOK FOG OUT OF THE 06Z PACKAGE...BUT
A LITTLE FOG HERE AND THERE...BEEN ADJUSTING THE FCST FOR
THIS.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
432 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN DURING
THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING MUCH
QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH SHOT
OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS TEMPERATURES
AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS TO TURN SW
LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND APPROACHES.
QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA AND PLENTY OF
SUN.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
SOME CLDS AROUND 3500 FEET JUST TO THE NORTH AND WEST OF
THE OFFICE...WILL PREVAIL THROUGH SUNRISE. NOT CLEAR WHY
THESE EXIST...BUT GIVEN THE CLDS...TOOK FOG OUT OF THE TAFS.
RADAR RETURNS MOVING FAST...NOT SEEING ANY MID LVL CLDS...
THUS HARD TO SEE WHY ANYTHING IS MOVING THIS FAST.
THERE COULD BE A BRIEF SPRINKLE ALONG THE MD BORDER LATER
TODAY AND SUNDAY NIGHT...BUT LIKELY TO BE SOUTH OF ANY OF
OUR TAF SITES.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
220 AM EDT SUN AUG 11 2013
.SYNOPSIS...
A WEAK WEATHER SYSTEM IS BRINGING VARIABLE CLOUD COVER TO THE
REGION OVERNIGHT TONIGHT. A FEW ISOLATED SHOWERS ARE POSSIBLE
ACROSS WESTERN PENNSYLVANIA. SUNDAY WILL FEATURE PARTLY TO MOSTLY
CLOUDY SKIES WITH JUST A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM
TO PORTIONS OF THE AREA. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
OVERVIEW...MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE IS IN VERY
GOOD AGREEMENT IN MAINTAINING A RELATIVELY AMPLIFIED PATTERN
THROUGH THE MIDDLE/LATE PART OF NEXT WEEK. THIS WILL BE GENERALLY
CHARACTERIZED BY FOUR CORNERS/ROCKIES UPPER RIDGING AND MEAN
TROUGHING OVER THE EASTERN THIRD OF THE CONUS. A POLAR FRONT WILL
PUSH SEWD FROM THE LOWER GRT LKS ACROSS THE MID-ATLANTIC/NORTHEAST
STATES ON TUESDAY. BEHIND THE FRONT...A LARGE DOME OF HIGH
PRESSURE BUILDING SEWD FROM THE SOUTH-CENTRAL CANADIAN PRAIRIES
WILL DOMINATE THE REGIONAL WEATHER PATTERN THROUGH THE END OF THE
PERIOD.
HIGHLIGHTS...AT LEAST MARGINAL/ISOLATED SEVERE TSTMS MAY BE
POSSIBLE ON DAY 4/TUE AS BROAD HEIGHT FALLS AND RELATIVELY COOL
TEMPERATURES/STRONG CYCLONIC WINDS ALOFT SPREAD ACROSS THE REGION
IN ASSOCIATION WITH THE AMPLIFYING UPPER TROUGH CROSSING THE GRT
LKS. DETAILS SUCH AS FRONTAL TIMING AND DEGREE OF DESTABILIZATION
ARE STILL IN QUESTION...HOWEVER A CATEGORICAL SLGT RISK OUTLOOK
SEEMS PROBABLE. ADDED 5-10 PCT TO POPS INCREASING TO LKLY IN MOST
AREAS...WHICH IS IN LINE WITH THE LATEST CONSENSUS MOS DATA.
A REFRESHINGLY COOL/DRY CANADIAN AIRMASS IS FCST TO FILTER INTO
THE AREA BEHIND THE FRONT. 10/12Z GEFS MEAN PWS STAY BELOW NORMAL
FROM TUE NGT THRU EARLY FRI...WHICH SUPPORTS A COOL AND DRY
MID/LATE WEEK PERIOD WITH TEMPERATURES AVERAGING BELOW NORMAL.
ALSO ANTICIPATE A FEW RELATIVELY COOL/CHILLY MORNINGS WITH UPPER
30S POSSIBLE A.M. THURSDAY OVER THE NRN TIER.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SOME CLDS AROUND 3500 FEET JUST TO THE NORTH AND WEST OF
THE OFFICE...WILL PREVAIL THROUGH SUNRISE. NOT CLEAR WHY
THESE EXIST...BUT GIVEN THE CLDS...TOOK FOG OUT OF THE TAFS.
RADAR RETURNS MOVING FAST...NOT SEEING ANY MID LVL CLDS...
THUS HARD TO SEE WHY ANYTHING IS MOVING THIS FAST.
THERE COULD BE A BRIEF SPRINKLE ALONG THE MD BORDER LATER
TODAY AND SUNDAY NIGHT...BUT LIKELY TO BE SOUTH OF ANY OF
OUR TAF SITES.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...STEINBUGL
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
156 AM EDT SUN AUG 11 2013
.SYNOPSIS...
A WEAK WEATHER SYSTEM IS BRINGING VARIABLE CLOUD COVER TO THE
REGION OVERNIGHT TONIGHT. A FEW ISOLATED SHOWERS ARE POSSIBLE
ACROSS WESTERN PENNSYLVANIA. SUNDAY WILL FEATURE PARTLY TO MOSTLY
CLOUDY SKIES WITH JUST A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM
TO PORTIONS OF THE AREA. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND TUESDAY
WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
OVERVIEW...MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE IS IN VERY
GOOD AGREEMENT IN MAINTAINING A RELATIVELY AMPLIFIED PATTERN
THROUGH THE MIDDLE/LATE PART OF NEXT WEEK. THIS WILL BE GENERALLY
CHARACTERIZED BY FOUR CORNERS/ROCKIES UPPER RIDGING AND MEAN
TROUGHING OVER THE EASTERN THIRD OF THE CONUS. A POLAR FRONT WILL
PUSH SEWD FROM THE LOWER GRT LKS ACROSS THE MID-ATLANTIC/NORTHEAST
STATES ON TUESDAY. BEHIND THE FRONT...A LARGE DOME OF HIGH
PRESSURE BUILDING SEWD FROM THE SOUTH-CENTRAL CANADIAN PRAIRIES
WILL DOMINATE THE REGIONAL WEATHER PATTERN THROUGH THE END OF THE
PERIOD.
HIGHLIGHTS...AT LEAST MARGINAL/ISOLATED SEVERE TSTMS MAY BE
POSSIBLE ON DAY 4/TUE AS BROAD HEIGHT FALLS AND RELATIVELY COOL
TEMPERATURES/STRONG CYCLONIC WINDS ALOFT SPREAD ACROSS THE REGION
IN ASSOCIATION WITH THE AMPLIFYING UPPER TROUGH CROSSING THE GRT
LKS. DETAILS SUCH AS FRONTAL TIMING AND DEGREE OF DESTABILIZATION
ARE STILL IN QUESTION...HOWEVER A CATEGORICAL SLGT RISK OUTLOOK
SEEMS PROBABLE. ADDED 5-10 PCT TO POPS INCREASING TO LKLY IN MOST
AREAS...WHICH IS IN LINE WITH THE LATEST CONSENSUS MOS DATA.
A REFRESHINGLY COOL/DRY CANADIAN AIRMASS IS FCST TO FILTER INTO
THE AREA BEHIND THE FRONT. 10/12Z GEFS MEAN PWS STAY BELOW NORMAL
FROM TUE NGT THRU EARLY FRI...WHICH SUPPORTS A COOL AND DRY
MID/LATE WEEK PERIOD WITH TEMPERATURES AVERAGING BELOW NORMAL.
ALSO ANTICIPATE A FEW RELATIVELY COOL/CHILLY MORNINGS WITH UPPER
30S POSSIBLE A.M. THURSDAY OVER THE NRN TIER.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MAINLY JUST SCT-BKN CIRRUS STREAMING OVERHEAD TONIGHT IN STRONG
WESTERLY FLOW ALOFT. BUT A WEAK DEWPOINT BOUNDARY OVER NW PA/E OH
COMBINED WITH LIGHT NE FLOW AT LOWER LEVELS AND SLIGHT CONVERGENCE
IN THE 850MB FLOW HAS INITIATED AN AREA OF STRATOCU BASED AROUND
4000 FT. THESE CLOUDS WILL LIKELY SLIP INTO KBFD-KJST OVER NEXT
FEW HOURS AND MAY LINGER MUCH OF THE OVERNIGHT. BUT OVERALL...VFR
CONDITIONS EXPECTED TONIGHT WITH ONLY SOME PATCHY VALLEY FOG
FORMING FOR A COUPLE HOURS CLOSE TO SUNRISE.
ON SUNDAY...A WEAK WEATHER DISTURBANCE WILL BRING A CHANCE FOR A
SHOWER ALONG THE PA/MD BORDER NEAR KJST LATE IN THE DAY...BUT WILL
HAVE A HARD TIME PUSHING NORTH/EAST OF THAT. VFR CONDITIONS AND
LIGHT WINDS CONTINUE.
OUTLOOK...
SUN-MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
MON NIGHT-TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND SCT
TSTMS.
TUE NIGHT-THU...PRIMARILY VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
915 PM CDT MON AUG 12 2013
.UPDATE...
MADE SOME MINOR ADJUSTMENTS TO POPS FOR THE OVERNIGHT PERIOD.
REMOVED THE MENTION THROUGH ABOUT MIDNIGHT OR SO...BUT LEFT A
SMALL POP IN ACROSS THE WEST AFTER THAT AS THE HRRR MODEL STILL
HINTING AT SOME DEVELOPMENT JUST WEST OF THE CWA IN ASSOCIATION
WITH A LLJ. NO CHANGES MADE TO WINDS OR TEMPERATURES AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
FORECAST CHALLENGES CENTER AROUND PCPN CHANCES OVER THE WESTERN
CWA THROUGH THE PERIOD. FOR TNT LATEST MESO DATA FROM SPC
INDICATES AN INSTABILITY AXIS ACROSS THE WESTERN CWA WHERE MLCAPES
ARE UP TO 1K J/KG AND DEEP LAYER SHEAR IS AROUND 40 KNOTS.
MEANWHILE LOW LEVEL SHEAR IS PRETTY WEAK AND PROBABLY LESS THAN 10
KNOTS. RECENT RADAR/SATELLITE DATA HAS SHOWN A FEW CELLS POPPING
BUT HAVING A HARD TIME MAINTAINING DECENT UPDRAFTS. PERHAPS DUE TO
MID LEVEL LAPSE RATES NOT BEING PARTICULARLY STEEP. SUSPECT THESE
ISOLATED/SCT SHOWERS WILL PERSIST INTO THE EARLY EVENING BEFORE
DIEING. OVERNIGHT A MODERATE LLJ IS EXPECTED TO BE FOCUSED OVER
THE WESTERN HALF OF THE STATE...AND THUS WILL KEEP SLIGHT CHC
MENTION OVERNIGHT FOR FAR WESTERN CWA. THE SETUP ON TUESDAY IS
ALMOST A CARBON COPY OF TODAY FROM A THERMAL/INSTABILITY/MOISTURE
POINT OF VIEW...ALTHOUGH TEMPERATURES MIGHT BE JUST A TOUCH COOLER
BASED ON H85 PROGS. THE EASTERN PART OF THE FORECAST AREA REMAINS
TRANQUIL UNDER DRY AIR AND STABLE LAPSE RATES...BUT MAY GET IN ON
THE ACT A BIT BY WEDNESDAY NIGHT AND THURSDAY AS
MOISTURE/INSTABILITY BEGINS SPREADING MORE EAST VS PREVIOUS DAYS.
FOR NOW IT APPEARS THE MAIN JUXTAPOSITION OF FEATURES COMING
TOGETHER TO SUPPORT SHOWERS/STORMS WOULD BE OVER THE SOUTHERN
CWA...AND THAT IS WHERE THE HIGHEST POPS WERE PLACED. TEMPERATURES
OVERALL THROUGH THE PERIOD SHOULD BE A SMIDGEN BELOW NORMAL...BOTH
HIGHS AND LOWS.
.LONG TERM...THURSDAY THROUGH MONDAY
ON THURSDAY...MODELS ARE SHOWING A DECENT MID LEVEL WAVE SLIDING
SOUTHEAST THROUGH THE DAKOTAS. WITH SURFACE HIGH PRESSURE SLIDING
EAST AND A LIGHT SOUTHEAST SFC WIND DIRECTION DEVELOPING...THERE
WILL BE SOME MOISTURE RETURN TO BE HAD AS DEWPOINTS RISE INTO THE
60S. SOME OF THURSDAYS ACTIVITY MAY LINGER INTO THURSDAY EVENING
AND HAVE GENERALLY ACCEPTED ALLBLEND POP GRIDS FOR THIS TIME
FRAME. FRIDAY AND SATURDAY LOOK TO BE DRY AT THIS TIME WITH
WARMING TEMPERATURES. IT APPEARS READINGS WILL ACTUALLY BE BACK TO
NEAR OR EVEN ABOVE NORMAL FOR THIS TIME OF YEAR...WHICH IS
SOMETHING WE HAVE NOT SEEN IN QUITE SOME TIME. MODELS THEN SHOW A
FRONTAL BOUNDARY CROSSING THE REGION SUNDAY NIGHT INTO
MONDAY...BRINGING ANOTHER CHANCE FOR PRECIPITATION.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
SCATTERED SHOWERS AND THUNDERSTORMS WILL TRACK SOUTHWARD ACROSS THE
FAR SOUTHERN CWA THROUGH THE EARLY EVENING HOURS. A FEW
THUNDERSTORMS ARE POSSIBLE AGAIN ACROSS THE SOUTHWESTERN CWA LATE
TUESDAY AFTERNOON. OTHERWISE...VFR CONDITIONS WILL PREVAIL TONIGHT
AND THROUGH THE DAY TUESDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...PARKIN
SHORT TERM...TDK
LONG TERM...TMT
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
320 PM CDT SUN AUG 11 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 317 PM CDT SUN AUG 11 2013
SURFACE BOUNDARY HAS SET UP FROM NEAR YANKTON SOUTH DAKOTA
NORTHEASTWARD TO CANTON AND EAST TO SPENCER. AIRMASS REMAINS WARM
AND UNSTABLE SOUTH OF THIS BOUNDARY WHERE TEMPERATURES HAVE ALREADY
RISEN INTO THE LOWER 80S WITH DEWPOINTS NEAR 70. RAP SOUNDINGS
SUGGEST THAT MUCAPE VALUES ARE OVER 2000 J/KG WITH EFFECTIVE SHEAR
NEAR 25 TO 35 KT IN THIS AREA. WITH CONTINUED DESTABILIZATION AND
VERY LITTLE CAPPING INDICATED...SCATTERED STORMS ARE EXPECTED TO
DEVELOP ACROSS THE SOUTHEASTERN CORNER OF THE FORECAST AREA WITHIN
THE NEXT FEW HOURS. STRATUS FIELD ENCOMPASSING THE BULK OF THE
FORECAST AREA COULD KEEP THE FOCUS JUST SOUTH OF THE FORECAST AREA
WHERE MID LEVEL LAPSE RATES ARE A BIT MORE IMPRESSIVE AND A LARGE
CUMULUS FIELD CAN BE SEEN ON SATELLITE.
WITH THE SURFACE LOW SLOWLY EDGING EASTWARD THROUGH THE
EVENING...THE BOUNDARY SHOULD BEGIN TO ADVANCE EASTWARD AND IS
EXPECTED TO EXIT THE FORECAST AREA BY AROUND 03Z. IF STORMS MANAGE
TO DEVELOP WITHIN OUR CWA...A FEW SEVERE STORMS WILL BE POSSIBLE AND
WILL POSE A THREAT OF HAIL UP TO GOLF BALLS AND 60 MPH WIND GUSTS.
PRECIPITABLE WATER VALUES REMAIN QUITE HIGH AT 1.5" OR HIGHER...SO
HEAVY RAINFALL WILL ALSO BE LIKELY WITH WITH SHOWERS AND STORMS.
STRATUS NEAR THE BOUNDARY WILL ALSO GRADUALLY BEGIN TO CLEAR OUR
FROM NORTHWEST TO SOUTHEAST THROUGH THIS EVENING BEHIND THIS
SYSTEM...BUT COULD BECOME HUNG UP NEAR THE MISSOURI VALLEY AND SOUTH
CENTRAL IOWA NEAR THE BAGGY PORTION OF THE FRONT. MONDAY WILL BE
ANOTHER PLEASANT LATE SUMMER DAY WITH RELATIVELY LIGHT WINDS AND
SLIGHTLY BELOW NORMAL TEMPERATURES AND PARTLY CLOUDY SKIES. HIGHS
WILL BE IN THE MID 70S TO LOWER 80S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 317 PM CDT SUN AUG 11 2013
MONDAY NIGHT THROUGH WEDNESDAY LOOKS TO STAY MAINLY DRY OVER THE
AREA AS WE REMAIN IN BETWEEN A DIGGING TROUGH TOWARDS THE EAST COAST
AND A BUILDING RIDGE WEST OF THE ROCKIES. HIGH PRESSURE DROPPING OUT
OF CANADA TO OUR EAST...WILL KEEP COOL EASTERLY FLOW OVER US...AND
SHOULD ALSO KEEP MOST OF THE INSTABILITY SOUTH AND WEST OF OUR CWA.
WOULD EXPECT DAILY ISOLATED TO SCATTERED STORM DEVELOPMENT IN THE
WESTERN PLAINS WHERE THE SOUTHEASTERLY UPSLOPE FLOW...CONVERGENCE
AND INSTABILITY ARE MAXIMIZED. HOWEVER THINK MOST OF THAT ACTIVITY
WILL STAY OUT OF OUR AREA. THE EXCEPTION COULD BE IN THE FAR
SOUTHWEST CORNER OF OUR CWA...TOWARDS GREGORY COUNTY...WHICH IS
CLOSE ENOUGH TO THIS ACTION TO WARRANT A LOW CHANCE POP EACH DAY AND
NIGHT. NAM IS A BIT MORE AGGRESSIVE WITH CONVECTION ALONG THE
MISSOURI RIVER AND WEST OF THE JAMES RIVER MONDAY NIGHT INTO
TUESDAY. IT IS FURTHER EAST WITH THE 850 MB BOUNDARY...ALLOWING
CONVERGENCE AND INSTABILITY TO CREEP FURTHER NORTHEAST. BUT SINCE IT
IS A PRETTY BIG OUTLIER AT THIS TIME...WILL STICK CLOSER TO THE
ECMWF AND GFS SOLUTIONS. LOWS MONDAY NIGHT AND TUESDAY NIGHT
DEPENDENT ON CLOUD COVER...BUT AT THIS POINT THINKING WE SEE ENOUGH
CLEARING TO GET SOME COOL LOWS EAST OF THE JAMES RIVER...WITH LOW
AND MID 50S EXPECTED. HIGHS TUESDAY AND WEDNESDAY WILL STAY BELOW
NORMAL...WITH MID AND UPPER 70S COMMON.
BY WEDNESDAY NIGHT THE RIDGING BEGINS TO PUSH NORTHEAST CLOSER TO
THE AREA AS OUR HIGH PRESSURE MOVES OFF TO THE EAST. THIS WILL ALLOW
LOW LEVEL SOUTHEASTERLY WINDS TO MOVE FURTHER INTO THE
AREA...ALLOWING FOR A SLOW INCREASE IN INSTABILITY. THIS WILL ALSO
ALLOW FOR NIGHTLY INCREASES IN THE LOW LEVEL JET WHICH SHOULD ACT TO
HELP INCREASE OUR PRECIP CHANCES. WEDNESDAY NIGHT MAY SEE SOME
ACTIVITY MAKE IT CLOSE TO INTERSTATE 29...AND BY THURSDAY INTO
THURSDAY NIGHT WE MIGHT BE ABLE TO GET SOME CONVECTION ACROSS THE
CWA. INSTABILITY STILL ON THE LOW SIDE AND FORCING NOT THAT
IMPRESSIVE...SO ONLY LOW CHANCE POPS WARRANTED AT THIS TIME. AS THE
RIDGING CONTINUES TO SLOWLY BUILD IN...STARTING TO LOOK LIKE FRIDAY
INTO THE WEEKEND WILL STAY DRY...WITH A WARMING TREND EACH DAY.
THURSDAY WILL SEE MID 70S TO NEAR 80...WITH READINGS NEAR 80 TO 85
OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1239 PM CDT SUN AUG 11 2013
SCATTERED MVFR CEILINGS NEAR THE STALLED BOUNDARY EXTEND ACROSS
SOUTHWEST MINNESOTA INTO MUCH OF SOUTHEAST SD. THESE CLOUDS WILL
SLOWLY SHIFT EASTWARD DISSIPATE THROUGH AROUND 00Z AS THE FRONT
DRIFTS SOUTHEAST. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO FIRE THIS AFTERNOON ALONG AND AHEAD OF
THE BOUNDARY...MAINLY SOUTH OF A VERMILION SD TO SPIRIT LAKE IA LINE.
IFR VISIBILITY AND LOW CEILINGS WILL BE POSSIBLE IN STORMS. A FEW
STRONG TO SEVERE STORMS WILL BE POSSIBLE FROM 21Z TO 03Z. WITH
SEVERAL MODELS INDICATING RATHER LIGHT WINDS OVERNIGHT AND GIVEN THE
RECENT HEAVY RAINFALL...ADDED SOME LOWER VISIBILITY AFTER 10Z IN HON
AND FSD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1004 AM CDT SUN AUG 11 2013
.UPDATE...
FRONTAL BOUNDARY JUST TO OUR NORTHWEST PROGGED TO SAG SOUTHEASTWARD
DURING THE DAY BEFORE RETREATING TONIGHT. EXPECT TO SEE SHOWERS
AND ISOLATED THUNDERSTORMS INCREASE IN NUMBER AS WE TO THROUGH THE
DAY ESPECIALLY ONCE HEATING CRANKS UP. NOT EXPECTING TO SEE MUCH
IN THE WAY OF ORGANIZATION OF ACTIVITY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 651 AM CDT SUN AUG 11 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL TIMING/AREAL SHWR/TSTMS COVERAGE AND IMPACTS...
IFR/MVFR FOG IMPACTS 11/12Z-11/13Z & 12/06Z-12/12Z. EXPECTING A GRADUAL
TREND FROM IFR-VFR CEILINGS TOWARD VFR BKN CU BY 11/17Z. WITH STATIONARY
FRONT EXPECTED TO DRIFT SLOWLY NWD THRU 12/12Z AND A CONTINUANCE OF ZONAL
FLOW ALOFT...STILL EXPECTING SCT SHWR/TSTM DEVELOPMENT...JUST VERY HARD TO
PINPOINT EXACT TIMING/AREAL COVERAGE...VCSH WITH VCTS REMARKS DIURNALLY BASED.
EXPECTING SOME DECREASE IN SHWR/TSTM ACTIVITY AFTER 12/06Z-12/08Z WITH
BREAKS IN CEILINGS ALLOWING FOR MVFR FOG FORMATION.
PREV DISCUSSION.../ISSUED 329 AM CDT SUN AUG 11 2013/
WEAK STATIONARY FRONTAL BOUNDARY IS POSITIONED JUST NW OF THE MID
STATE THIS MORNING. IT NOW APPEARS THAT THIS FEATURE WILL MOVE
LITTLE OVER THE NEXT 24-48 HRS. OTW..CURRENT RADAR SHOWING SOME
SCT CONVECTION ACROSS FAR NORTHERN PORTIONS OF THE MID STATE.
WESTERLIES ALOFT ARE STILL IN PLACE AS THE W-E UPPER RIDGE REMAIN
SUPPRESSED TO OUR SOUTH.
LATEST HRRR SUPPORTING LESS IN THE WAY OF CONVECTION TODAY AND
TONIGHT. THIS IS FURTHER ENFORCED BY DRIER MOISTURE DEPTH LEVELS AS
COMPARED TO PREVIOUS DAYS. STILL THOUGH...PLENTY OF HUMIDITY TO
WORK WITH AND CANNOT RULES OUT LOW POPS FOR TODAY AND TONIGHT IN THE
20-40 PERCENT RANGE.
AS WE GO THROUGH MONDAY AND TUESDAY...MID LEVEL TEMPS WILL BEGIN TO
COOL AS AN UPCOMING TROUGHING PATTERN BEGINS TO EMERGE. AS OUR WINDS
ALOFT BECOME MORE NORTHERLY...A STRONGER COLD FRONT WILL BEGIN TO
PUSH SOUTHWARD AND FURTHER INCREASE PRECIP CHANCES. LOOKS AS THOUGH
THE FROPA WILL OCCUR SOMETIME LATE WEDNESDAY AS IT APPEARS TO SLOW
DOWN A BIT. WILL GO AHEAD AND INCLUDE INCREASING POPS WITH TIME WITH
LIKELY VALUES BY TUESDAY. TEMPERATURES WILL RUN A DEGREE OR TWO
ABOVE NORMAL. MOS NUMBERS LOOK REASONABLE.
IN THE EXT FCST...SHOWER AND TSTM CHANCES WILL REMAIN RATHER HIGH ON
WEDNESDAY AS THE FRONT REMAINS IN CLOSE PROXIMITY. SOME DRIER AIR
WILL WORK IN THU-SAT BUT AFTERNOON ELEVATED CAPE VALUES WILL
RETURN BY THE WEEKEND. THEREFORE...LOW 20-30 POPS WILL RETURN BY
THE TAIL END OF THE EXTENDED.
OTW...STILL LOOKING AT A COOLING TREND FOR THE EXT WITH LOWS MID TO
UPPER 60S...HIGHS MID 80S...COOLER PLATEAU.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
925 AM EDT SUN AUG 11 2013
.DISCUSSION...SHOWERS AND STORMS ALREADY ON THE INCREASE THIS
MORNING AND TRAINING ALONG THE FRONTAL BOUNDARY...ALONG AND JUST
NORTH OF TN/KY STATELINE EAST INTO SW VA. COVERAGE HAS INCREASED
ENOUGH...THAT I WILL LIKELY UPDATE GRIDS AND PRODUCTS BY MID MORNING
RATHER THAN NOON TODAY. LATEST RUC MODEL RUN SPREADS CONVECTION OVER
THE BULK OF THE FORECAST AREA THROUGH THE AFTERNOON...SO PLAN TO
KEEP OR EVEN EXPAND LIKELY POPS FOR TODAY.
LOCALLY HEAVY RAINS THE MAIN THREAT AS HAS BEEN FOR THE PAST FEW
DAYS. HOWEVER...24 HOUR RAINFALL PRODUCT FROM MORRISTOWN AND HYTOP
RADARS SHOWED FEWER POCKETS OF VERY HEAVY RAINS OVER THE PAST 24
HOURS.
FOG IS DISSIPATING AND LOW CLOUD DECK LIFTING AT THIS TIME...SO WILL
ALSO REMOVE FOG AND MORNING WORDING IN THE UPDATE. MOS MAX TEMPS FOR
TODAY WERE UNDERCUT AND THIS SHOULD WORK OUT WELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 89 72 88 72 83 / 60 30 50 50 70
KNOXVILLE MCGHEE TYSON AIRPORT, TN 89 70 86 71 81 / 60 20 40 50 60
OAK RIDGE, TN 89 69 86 70 82 / 60 20 40 50 70
TRI CITIES AIRPORT, TN 88 65 83 66 78 / 50 20 40 50 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
651 AM CDT SUN AUG 11 2013
.UPDATE...FOR 12Z AVIATION DISCUSSION.
&&
.AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL TIMING/AREAL SHWR/TSTMS COVERAGE AND IMPACTS...
IFR/MVFR FOG IMPACTS 11/12Z-11/13Z & 12/06Z-12/12Z. EXPECTING A GRADUAL
TREND FROM IFR-VFR CEILINGS TOWARD VFR BKN CU BY 11/17Z. WITH STATIONARY
FRONT EXPECTED TO DRIFT SLOWLY NWD THRU 12/12Z AND A CONTINUANCE OF ZONAL
FLOW ALOFT...STILL EXPECTING SCT SHWR/TSTM DEVELOPMENT...JUST VERY HARD TO
PINPOINT EXACT TIMING/AREAL COVERAGE...VCSH WITH VCTS REMARKS DIURNALLY BASED.
EXPECTING SOME DECREASE IN SHWR/TSTM ACTIVITY AFTER 12/06Z-12/08Z WITH
BREAKS IN CEILINGS ALLOWING FOR MVFR FOG FORMATION.
&&
.PREV DISCUSSION.../ISSUED 329 AM CDT SUN AUG 11 2013/
WEAK STATIONARY FRONTAL BOUNDARY IS POSITIONED JUST NW OF THE MID
STATE THIS MORNING. IT NOW APPEARS THAT THIS FEATURE WILL MOVE
LITTLE OVER THE NEXT 24-48 HRS. OTW..CURRENT RADAR SHOWING SOME
SCT CONVECTION ACROSS FAR NORTHERN PORTIONS OF THE MID STATE.
WESTERLIES ALOFT ARE STILL IN PLACE AS THE W-E UPPER RIDGE REMAIN
SUPPRESSED TO OUR SOUTH.
LATEST HRRR SUPPORTING LESS IN THE WAY OF CONVECTION TODAY AND
TONIGHT. THIS IS FURTHER ENFORCED BY DRIER MOISTURE DEPTH LEVELS AS
COMPARED TO PREVIOUS DAYS. STILL THOUGH...PLENTY OF HUMIDITY TO
WORK WITH AND CANNOT RULES OUT LOW POPS FOR TODAY AND TONIGHT IN THE
20-40 PERCENT RANGE.
AS WE GO THROUGH MONDAY AND TUESDAY...MID LEVEL TEMPS WILL BEGIN TO
COOL AS AN UPCOMING TROUGHING PATTERN BEGINS TO EMERGE. AS OUR WINDS
ALOFT BECOME MORE NORTHERLY...A STRONGER COLD FRONT WILL BEGIN TO
PUSH SOUTHWARD AND FURTHER INCREASE PRECIP CHANCES. LOOKS AS THOUGH
THE FROPA WILL OCCUR SOMETIME LATE WEDNESDAY AS IT APPEARS TO SLOW
DOWN A BIT. WILL GO AHEAD AND INCLUDE INCREASING POPS WITH TIME WITH
LIKELY VALUES BY TUESDAY. TEMPERATURES WILL RUN A DEGREE OR TWO
ABOVE NORMAL. MOS NUMBERS LOOK REASONABLE.
IN THE EXT FCST...SHOWER AND TSTM CHANCES WILL REMAIN RATHER HIGH ON
WEDNESDAY AS THE FRONT REMAINS IN CLOSE PROXIMITY. SOME DRIER AIR
WILL WORK IN THU-SAT BUT AFTERNOON ELEVATED CAPE VALUES WILL
RETURN BY THE WEEKEND. THEREFORE...LOW 20-30 POPS WILL RETURN BY
THE TAIL END OF THE EXTENDED.
OTW...STILL LOOKING AT A COOLING TREND FOR THE EXT WITH LOWS MID TO
UPPER 60S...HIGHS MID 80S...COOLER PLATEAU.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
329 AM CDT SUN AUG 11 2013
DISCUSSION...
WEAK STATIONARY FRONTAL BOUNDARY IS POSITIONED JUST NW OF THE MID
STATE THIS MORNING. IT NOW APPEARS THAT THIS FEATURE WILL MOVE
LITTLE OVER THE NEXT 24-48 HRS. OTW..CURRENT RADAR SHOWING SOME SCT
CONVECTION ACROSS FAR NORTHERN PORTIONS OF THE MID STATE. WESTERLIES
ALOFT ARE STILL IN PLACE AS THE W-E UPPER RIDGE REMAIN SUPPRESSED TO
OUR SOUTH.
LATEST HRRR SUPPORTING LESS IN THE WAY OF CONVECTION TODAY AND
TONIGHT. THIS IS FURTHER ENFORCED BY DRIER MOISTURE DEPTH LEVELS AS
COMPARED TO PREVIOUS DAYS. STILL THOUGH...PLENTY OF HUMIDITY TO
WORK WITH AND CANNOT RULES OUT LOW POPS FOR TODAY AND TONIGHT IN THE
20-40 PERCENT RANGE.
AS WE GO THROUGH MONDAY AND TUESDAY...MID LEVEL TEMPS WILL BEGIN TO
COOL AS AN UPCOMING TROUGHING PATTERN BEGINS TO EMERGE. AS OUR WINDS
ALOFT BECOME MORE NORTHERLY...A STRONGER COLD FRONT WILL BEGIN TO
PUSH SOUTHWARD AND FURTHER INCREASE PRECIP CHANCES. LOOKS AS THOUGH
THE FROPA WILL OCCUR SOMETIME LATE WEDNESDAY AS IT APPEARS TO SLOW
DOWN A BIT. WILL GO AHEAD AND INCLUDE INCREASING POPS WITH TIME WITH
LIKELY VALUES BY TUESDAY. TEMPERATURES WILL RUN A DEGREE OR TWO
ABOVE NORMAL. MOS NUMBERS LOOK REASONABLE.
IN THE EXT FCST...SHOWER AND TSTM CHANCES WILL REMAIN RATHER HIGH ON
WEDNESDAY AS THE FRONT REMAINS IN CLOSE PROXIMITY. SOME DRIER AIR
WILL WORK IN THU-SAT BUT AFTERNOON ELEVATED CAPE VALUES WILL
RETURN BY THE WEEKEND. THEREFORE...LOW 20-30 POPS WILL RETURN BY
THE TAIL END OF THE EXTENDED.
OTW...STILL LOOKING AT A COOLING TREND FOR THE EXT WITH LOWS MID TO
UPPER 60S...HIGHS MID 80S...COOLER PLATEAU.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 89 72 89 71 / 30 30 40 50
CLARKSVILLE 88 68 89 68 / 30 30 40 50
CROSSVILLE 84 66 84 66 / 40 30 40 50
COLUMBIA 89 72 89 71 / 40 30 50 50
LAWRENCEBURG 89 70 88 70 / 40 30 50 50
WAVERLY 88 69 89 69 / 30 30 40 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
609 PM CDT MON AUG 12 2013
&&
.AVIATION...
PREVAILING VFR CONDITIONS EXPECTED THROUGH THE MAJORITY OF THIS
TAF CYCLE. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE POSSIBLE
AT CDS THROUGH 08Z...WITH BRIEF GUSTY WINDS TO 50 MPH AND HEAVY
DOWNPOURS POSSIBLE IF A STORM MANAGES TO MOVE THROUGH THE
TERMINAL. THUNDERSTORM CHANCES WILL INCREASE TOMORROW AFTERNOON
WITH THE PASSAGE OF A COLD FRONT AT APPROXIMATELY 20Z...ALTHOUGH
THERE REMAINS SOME UNCERTAINTY REGARDING THE TIMING OF THIS
FEATURE. BEST TSRA CHANCES WILL BE AT CDS...WITH SOMEWHAT LOWER
CHANCES AT KLBB LATER IN THE AFTERNOON AS THE FRONT PUSHES TOWARD
THE SOUTH.
&&
.PREV DISCUSSION... /ISSUED 346 PM CDT MON AUG 12 2013/
SHORT TERM...
WEATHER PATTERN OVER THE NEXT DAY WILL BE LARGELY DRIVEN BY
ELONGATED UPPER HIGH ALONG THE GULF COAST WITH A RIDGE EXTENDING
FROM AROUND THESE PARTS UP TO THE CANADIAN PRAIRIES. MONSOON
MOISTURE CONTINUES TO WRAP AROUND THE PERIPHERY OF THE HIGH CENTER
GENERALLY STREAMING FROM NORTHEASTERN NEW MEXICO TO THE TEXAS
PANHANDLE AND BEYOND. AREA OF SYNOPTIC SCALE LIFT IS EVIDENT TO OUR
NORTH AND NORTHWEST AND THIS IS WHERE TSTM ACTIVITY INITIATED.
HOWEVER...TO THE SOUTH...ACROSS OUR REGION...AXIS OF THETA-E MAXIMA
HAS HELPED INITIATE ISOLATED CONVECTION FROM DORA TO MEMPHIS. GIVEN
THAT THESE SHOWERS DEVELOPED BY 2PM...INDICATIONS ARE THAT THE
ATMOSPHERE IS SUFFICIENTLY MOIST TO SUPPORT AT LEAST SCATTERED STORMS
FOR MUCH OF THE AFTERNOON INTO THE EVENING HOURS...FAVORING THE
NORTHERN HALF OF THE AREA. AN INTERESTING SOLUTION IS EVIDENT IN
THE HRRR WITH CONVECTION FORMING OUT NORTHWEST OF LUBBOCK AND MOVING
SLOWLY THIS WAY...BUT PERHAPS NOT REACHING THE CITY. GIVEN THAT
THIS SOLUTION IS SOMEWHAT REPRESENTED IN LOCATION / THOUGH NOT
COVERAGE / HAVE EXPANDED POPS SOUTHWARD THIS EVENING. LIKE THE PAST
SEVERAL NIGHTS...LOW-END SEVERE STORMS WILL BE POSSIBLE WITH
CONDITIONS WANING TUESDAY MORNING FOR A WHILE. A BACK DOOR FRONT
IS INDICATED BY GUIDANCE AND WITH THE ALREADY PLENTIFUL CONVECTION
ACROSS THE PANHANDLE...PREFER THE QUICKER SOLUTION AND AS SUCH
HAVE BROUGHT THE BOUNDARY...AND ASSOCIATED INCREASED RAIN
CHANCES...INTO OUR CWFA DURING THE AFTERNOON ON TUESDAY.
LONG TERM...
MID-LEVEL PATTERN WILL CONTINUE TO AMPLIFY INTO THE EXTENDED WITH
STRONGER NW FLOW AND DEEP LAYER SHEAR ACROSS THE SOUTH PLAINS TUE
PM INTO WED IN THE WAKE OF THE FRONTAL BOUNDARY. THIS SCENARIO
SHOULD SUPPORT CONTINUED WIDESPREAD PRECIP CHANCES AS MOST MODELS
SUPPORT SOME Q-G LIFT ALONG WITH FRONTOGENETICAL FORCING CENTERED
OVER ERN NM INTO THE WRN SOUTH PLAINS. FAVORABLE 700MB THETA-E AXIS ALSO
REMAINS IN PLACE WITH PWATS INCREASING THROUGH THE FIRST COUPLE OF
DAYS OF THE EXTENDED PERIOD AS WELL. ONE LIMITING FACTOR FOR
CONSIDERATION FOR INCREASED COVERAGE WITH TIME IS THE INSTABILITY
DURING THE DAY WED. EXPECT CONSIDERABLE CLOUDINESS AND UPSLOPE
FLOW TO INHIBIT WARMING AND SUBSTANTIAL CAPE HOWEVER DEEPLY MOIST
ATMOSPHERE SHOULD AID DEVELOPMENT LOCALLY. ADDITIONAL HEATING
ACROSS EASTERN NM COUPLED WITH AMPLE SHEAR SHOULD HELP SOME
ACTIVITY TO ORGANIZE AND MOVE ACROSS THE WESTERN HALF OF THE AREA
AGAIN LATE EVENING AND OVERNIGHT WED NIGHT. SUBTLE SHORTWV
ACTIVITY TRAVERSING THE NW FLOW WILL HELP SUSTAIN AFTN STORMS THU
IN CONTINUED LIGHT UPSLOPE FLOW. ONCE AGAIN UNCAPPED ATMOSPHERE WILL
ALLOW SHOWERS TO FORM EARLY AND PREVENT THINGS FROM BECOMING TOO
UNSTABLE WITH SEVERE THREAT LIMITED OUTSIDE OF SOME HEAVY RAINERS.
FLOW TURNS MORE NRLY ON FRI AS RIDGE BUILDS FROM 4 CORNERS INTO
MONTANA. GFS AND EURO BOTH SUPPORT UPPER LOW DROPPING INTO THE MO
VALLEY ON SAT TO MAINTAIN SOME LIFT WITHIN REMNANT MOIST AXIS ON
EASTERN SIDE OF THE RIDGE. WITH CONTINUED ISOLD-SCT CONVECTION
POSSIBLE HAVE KEPT POPS GOING INTO THE WEEKEND WITH LITTLE TO NO
OVERALL WARMING TREND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 89 65 81 61 / 30 30 50 50 40
TULIA 65 89 67 80 62 / 30 30 50 50 40
PLAINVIEW 66 91 68 80 63 / 30 30 40 50 40
LEVELLAND 70 94 68 84 65 / 20 20 30 50 40
LUBBOCK 70 93 69 83 65 / 20 20 30 50 40
DENVER CITY 72 92 65 88 66 / 10 10 20 40 40
BROWNFIELD 73 94 70 86 66 / 10 10 20 50 40
CHILDRESS 72 96 69 84 67 / 30 40 50 50 30
SPUR 75 97 74 86 68 / 20 20 30 50 40
ASPERMONT 76 99 75 89 69 / 20 20 30 50 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
16/99/99
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1242 PM CDT SUN AUG 11 2013
.DISCUSSION...UPDATED FOR THE 18Z AVIATION DISCUSSION.
&&
.AVIATION...CONVECTION IS SLOW TO DEVELOP...BUT STARTING TO SEE
MORE DEVELOPMENT WITH ADDITIONAL HEATING. SIMILAR SET UP TO
YESTERDAY...WITH MOST ACTIVITY DEVELOPING ALONG THE SEA BREEZE
AFFECTING CRP-VCT-ALI BETWEEN 18Z-22Z...THEN LRD BTWN 22Z-00Z.
BRIEF MVFR VSBY/CIGS IN AND AROUND ANY THUNDERSTORMS...WITH GUSTY
WIND. OTHERWISE VFR THROUGH THE EVENING. REDEVELOPMENT OF STRATUS
AND FOG IS EXPECTED EARLY MONDAY...HOWEVER MVFR CONDITIONS WERE
VERY BRIEF AND PATCHY SO WILL NOT MENTION AT THIS TIME WITH THE
EXCEPTION OF VCT. AS FOR WINDS...GENERAL 10-15KT E-SE WINDS THIS
AFTERNOON...BECOMING LIGHT AND VARIABLE OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1042 AM CDT SUN AUG 11 2013/
DISCUSSION...UPDATED HOURLY GRIDS TO REFLECT TRENDS. THE BULK OF
THE SHOWER AND THUNDER ACTIVITY REMAINS WELL SOUTH OF THE CWA...AS
THE UPPER LOW IS POSITIONED FARTHER SOUTH THAN EXPECTED. HOWEVER
MODELS CONTINUE TO SHIFT THE LOW AND THE ASSOCIATED SURFACE
COASTAL TROUGH WEST ACROSS THE REGION. WITH AN UNSTABLE AIRMASS
AND LITTLE TO NO CAPPING...WILL CONTINUE TO EXPECT COVERAGE TO
FILL IN THROUGH THE EARLY AFTERNOON...WITH BETTER DEVELOPMENT OVER
LAND ALONG THE SEA BREEZE. ACTIVITY SHOULD DIMINISH THIS LATE
AFTERNOON/EARLY EVENING WITH THE LOSS OF HEATING.
PREV DISCUSSION... /ISSUED 630 AM CDT SUN AUG 11 2013/
DISCUSSION...SEE 12Z AVIATION DISCUSSION.
AVIATION...PRETTY MUCH NO CHANGE IN THE TIMING OF THE CONVECTION
AS THAT STILL LOOKS GOOD. ANOTHER ROUND OF SCATTERED CONVECTION
EXPECTED TODAY...AND PRETTY MUCH KEPT TIMING OF THE TEMPOS WITH
VCTS STARTING ABOUT AN HOUR BEFORE TEMPO AND ENDING ABOUT ONE HOUR
AFTER TEMPO ENDS. SOME MORNING MVFR BR AND HAVE INCLUDED IN KALI
AND KVCT BUT CANNOT RULE OUT IT OCCURRING IN KCRP AND KLRD.
OTHERWISE...VFR CONDITIONS OUTSIDE OF CONVECTION. WINDS AGAIN
START OFF LIGHT AND VARIABLE THIS MORNING...GRADUALLY VEERING
DURING THE DAY/AFTERNOON AND BECOMING SOUTHEAST GENERALLY LESS
THAN 11 KNOTS (OUTSIDE OF THUNDER). WINDS BECOME VERY LIGHT AOB
06Z...AND COULD HAVE FOG AGAIN AT KVCT AND KALI BEFORE END OF
TERMINAL FORECAST. HELD OFF AT KALI BUT PUT 5SM BR AT KVCT ABOUT
09Z. NO RAINFALL FORECAST FOR THE OVERNIGHT PERIOD.
PREV DISCUSSION... /ISSUED 346 AM CDT SUN AUG 11 2013/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 30 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 30 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...AVIATION
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1042 AM CDT SUN AUG 11 2013
.DISCUSSION...UPDATED HOURLY GRIDS TO REFLECT TRENDS. THE BULK OF
THE SHOWER AND THUNDER ACTIVITY REMAINS WELL SOUTH OF THE CWA...AS
THE UPPER LOW IS POSITIONED FARTHER SOUTH THAN EXPECTED. HOWEVER
MODELS CONTINUE TO SHIFT THE LOW AND THE ASSOCIATED SURFACE
COASTAL TROUGH WEST ACROSS THE REGION. WITH AN UNSTABLE AIRMASS
AND LITTLE TO NO CAPPING...WILL CONTINUE TO EXPECT COVERAGE TO
FILL IN THROUGH THE EARLY AFTERNOON...WITH BETTER DEVELOPMENT OVER
LAND ALONG THE SEA BREEZE. ACTIVITY SHOULD DIMINISH THIS LATE
AFTERNOON/EARLY EVENING WITH THE LOSS OF HEATING.
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT SUN AUG 11 2013/
DISCUSSION...SEE 12Z AVIATION DISCUSSION.
AVIATION...PRETTY MUCH NO CHANGE IN THE TIMING OF THE CONVECTION
AS THAT STILL LOOKS GOOD. ANOTHER ROUND OF SCATTERED CONVECTION
EXPECTED TODAY...AND PRETTY MUCH KEPT TIMING OF THE TEMPOS WITH
VCTS STARTING ABOUT AN HOUR BEFORE TEMPO AND ENDING ABOUT ONE HOUR
AFTER TEMPO ENDS. SOME MORNING MVFR BR AND HAVE INCLUDED IN KALI
AND KVCT BUT CANNOT RULE OUT IT OCCURRING IN KCRP AND KLRD.
OTHERWISE...VFR CONDITIONS OUTSIDE OF CONVECTION. WINDS AGAIN
START OFF LIGHT AND VARIABLE THIS MORNING...GRADUALLY VEERING
DURING THE DAY/AFTERNOON AND BECOMING SOUTHEAST GENERALLY LESS
THAN 11 KNOTS (OUTSIDE OF THUNDER). WINDS BECOME VERY LIGHT AOB
06Z...AND COULD HAVE FOG AGAIN AT KVCT AND KALI BEFORE END OF
TERMINAL FORECAST. HELD OFF AT KALI BUT PUT 5SM BR AT KVCT ABOUT
09Z. NO RAINFALL FORECAST FOR THE OVERNIGHT PERIOD.
PREV DISCUSSION... /ISSUED 346 AM CDT SUN AUG 11 2013/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 30 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 30 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
630 AM CDT SUN AUG 11 2013
.DISCUSSION...SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...PRETTY MUCH NO CHANGE IN THE TIMING OF THE CONVECTION
AS THAT STILL LOOKS GOOD. ANOTHER ROUND OF SCATTERED CONVECTION
EXPECTED TODAY...AND PRETTY MUCH KEPT TIMING OF THE TEMPOS WITH
VCTS STARTING ABOUT AN HOUR BEFORE TEMPO AND ENDING ABOUT ONE HOUR
AFTER TEMPO ENDS. SOME MORNING MVFR BR AND HAVE INCLUDED IN KALI
AND KVCT BUT CANNOT RULE OUT IT OCCURRING IN KCRP AND KLRD.
OTHERWISE...VFR CONDITIONS OUTSIDE OF CONVECTION. WINDS AGAIN
START OFF LIGHT AND VARIABLE THIS MORNING...GRADUALLY VEERING
DURING THE DAY/AFTERNOON AND BECOMING SOUTHEAST GENERALLY LESS
THAN 11 KNOTS (OUTSIDE OF THUNDER). WINDS BECOME VERY LIGHT AOB
06Z...AND COULD HAVE FOG AGAIN AT KVCT AND KALI BEFORE END OF
TERMINAL FORECAST. HELD OFF AT KALI BUT PUT 5SM BR AT KVCT ABOUT
09Z. NO RAINFALL FORECAST FOR THE OVERNIGHT PERIOD.
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT SUN AUG 11 2013/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 40 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 40 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
346 AM CDT SUN AUG 11 2013
.SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
&&
.MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
&&
.LONG-TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 40 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 40 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
PZ/83...LONG TERM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
754 PM EDT MON AUG 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TONIGHT AND WILL CROSS THROUGH
THE REGION ON TUESDAY. A LARGE HIGH PRESSURE SYSTEM WILL BUILDS IN
OVER THE OHIO VALLEY AND NEW ENGLAND TUESDAY NIGHT AND
WEDNESDAY...WHICH WILL BRING IN COOLER AND DRIER WEATHER.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 700 PM EDT MONDAY...
JUICY AIR/THETA-E RIDGE OVER SW VA AND SHORTWAVE ALOFT ACROSS ERN
KY ALLOWING FOR CONVECTION TO MAINTAIN ITSELF THRU THE I-77
CORRIDOR THIS EVENING. LINE OF SHOWERS FURTHER NORTH WEAKENING AS
THEY ENCOUNTER MORE STABLE AIR. HAVE UPPEP POPS ACROSS THE WEST
THIS EVENING AND AM PROBABLY GOING TO HAVE TO INCREASE THEM AGAIN
FURTHER EAST OF CARROLL COUNTY IF THE LINE HOLDS TOGETHER. THE 19Z
HRRR WAS HANDLING THIS OKAY BUT SEEMS TO BE TOO SLOW.
PREVIOUS VALID DISCUSSION...`
PRECIPITABLE WATER VALUES WERE BACK UP IN THE 1.5 TO 1.9 INCH
RANGE AND WILL REMAIN NEAR THOSE VALUES UNTIL THE FRONT GOES
THROUGH. FOCUS OF LIFT REMAINS IN THE WESTERN AND NORTHERN COUNTY
WARNING AREA WITH THE SHORT WAVE COMING OUT OF KENTUCKY THIS
EVENING. HRRR HAS THIS PRECIPITATION IN THE COUNTY WARNING AREA
BETWEEN 6PM AND 2AM. ALSO EXPECTING SCATTERED LATE AFTERNOON AND
EVENING THUNDERSTORMS ALONG THE SOUTHERN BLUE RIDGE INTO THE
ADJACENT FOOTHILLS. COVERAGE OF THESE STORMS WILL DIMINISH AFTER
SUNSET. PRECIPITATION WITH THE FRONT WILL HAVE THE BEST AREAL
COVERAGE IN THE WEST FROM 2AM/06Z THROUGH 12Z/8AM. THEN AS THE
FRONT MOVES SOUTHEAST INTO THE MORE UNSTABLE AIR MASS IN THE
PIEDMONT...THE HIGHEST PROBABILITY OF PRECIPITATION AFTER 18Z/2PM
WILL BE EAST OF THE BLUE RIDGE.
WILL TREND TOWARD WARMER GUIDANCE FOR OVERNIGHT LOWS AHEAD OF THE
FRONT. NOT EXPECTING A LARGE TEMPERATURE RISE IN THE WEST TUESDAY
BEHIND THE FRONT...WITH THE PRECIPITATION AND CLOUD COVER. WILL USE
A BLEND OF GUIDANCE IN THE EAST FOR HIGHS TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 230 PM EDT MONDAY...
TUESDAY NIGHT WE EXPECT SHOWERS AND SOME LINGERING STORMS TO
CONTINUE INTO THE EVENING HOURS IN ASSOCIATION WITH THE EXITING COLD
FRONT. THE GREATEST CONCENTRATION OF THESE WILL BE ALONG AND EAST OF
A LINE FROM LYNCHBURG VA TO REIDSVILLE NC. THE ACTIVITY WILL
PROGRESS EASTWARD OUR OF THE REGION AS THE NIGHT PROGRESSES.
LINGERING MOISTURE IN THE WESTERN PART OF THE AREA AND NORTHWEST
FLOW WILL ALLOW FOR SOME ISOLATED UPSLOPE SHOWERS ACROSS SOUTHEAST
WEST VIRGINIA THROUGH ABOUT MIDNIGHT.
DRIER AIR WORKS ITS WAY INTO THE REGION BY WEDNESDAY MORNING...AND
LATEST GUIDANCE PLACES THE INFLUENCE OF THE FRONT TO OUR SOUTH.
SURFACE HIGH PRESSURE WILL BUILD SOUTH ALONG THE LEE OF THE
APPALACHIANS WEDNESDAY NIGHT INTO THURSDAY. ANTI-CYCLONIC FLOW
AROUND THE HIGH MAY HELP BRING A BIT OF MOISTURE BACK INTO THE
NORTHERN MOUNTAINS AND FOOTHILLS OF OF NC DURING THIS TIME
PERIOD...ALONG WITH A SMALL CHANCE OF SOME SHOWERS.
OTHERWISE...DRIER AND COOLER WEATHER IS EXPECTED DURING THIS PORTION
OF THE FORECAST. ALTHOUGH...CLOUD COVER MAY STAY
ABUNDANT...ESPECIALLY ACROSS THE SOUTH...AS THE FLOW AROUND THE HIGH
BEGINS TO TAP ATLANTIC MOISTURE AND ADVECTS IT ACROSS OUR REGION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 1230 PM EDT MONDAY...
THE LATTER HALF OF THE FORECAST PERIOD WILL BE MARKED AS ONE WITH
PROGRESSIVELY INCREASING CHANCES OF PRECIPITATION. THE AXIS OF THE
DRY UPPER TROUGH AND SURFACE HIGH PRESSURE SYSTEM OVER THE REGION
WILL BEGIN TO SHIFT EASTWARD. WHILE THIS IS TAKING PLACE...MODEL
GUIDANCE OFFERS A SOLUTIONS THAT PLACE A DEVELOPING UPPER LOW OVER
THE CENTRAL U.S. AND A STRENGTHENING POTENTIAL TROPICAL LOW IN THE
NORTHERN GULF OF MEXICO. HOW THE TWO LOW PRESSURE CENTERS WILL
INTERACT WITH EACH OTHER STILL IS NOT AT A HIGH CONFIDENCE LEVEL.
HOWEVER...WHAT IS GAINING IN CONFIDENCE IS INCREASING EASTERLY FLOW
ACROSS THE REGION ON THE NORTHEAST SIDE OF THE SYSTEM/S. THIS WILL
HELP MAINTAIN THE TAIL OF THE DEPARTING HIGH ALONG THE LEE OF THE
APPALACHIANS FOR A BIT LONGER THAN EARLIER FORECASTS OFFERED. AS
SUCH...TODAY/S FORECAST FOR THURSDAY NIGHT INTO FRIDAY OFFERS A
SOMEWHAT DRIER...ALBEIT CLOUDY FORECAST FOR THE AREA. LIGHT RAIN
WILL CONTINUE TO BE MENTIONED OVER THE NORTHERN MOUNTAINS AND
FOOTHILLS OF NORTH CAROLINA.
AS WE PROGRESS INTO THE WEEKEND...CURRENT MODEL TRENDS OFFER A
STALLED DEEPENING LOW OVER THE CENTRAL U.S. WITH THE LOW ALONG THE
GULF BEING TRANSPORTED NORTHWARD ON THE EAST SIDE OF THE CENTRAL
CONUS TROUGH. THIS WOULD ALLOW FOR BETTER DYNAMICS AND MOISTURE
FLOW ACROSS THE REGION. THIS WILL LEAD TO BETTER CHANCE OF FIRST
LIGHT TO MODERATE RAIN OVER THE AREA THROUGH SATURDAY...AND THEN
BETTER CHANCES OF SHOWERS AND SOME THUNDERSTORMS BY SUNDAY. WHILE
ACTIVITY MAY TAPER OFF A BIT ON MONDAY...THE CENTRAL CONUS TROUGH
WOULD STILL BE TO OUR WEST BE A FEATURE TO POTENTIALLY INFLUENCE OUR
WEATHER PAST DAY 7.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 730 PM EDT MONDAY...
STRONG STORMS MOVING SOUTH OF BCB AT THE MOMENT WITH SOME CLOUD TO
GROUND STRKES NEAR BCB. THINING VCTS AT BCB WITH VFR...TEMPO MVFR
WITH MODERATE SHOWERS. SHOULD BE A BREAK IN SHOWERS AT LWB/BLF AS
THE LINE IS NOW MOVING OUT OF THERE. ALSO HAVE TEMPO AT ROA FOR
MVFR WITH SHOWERS. THINK THE SHOWER WILL WEAKEN FURTHER EAST
ALTHOUGH DANVILLE STILL UNSTABLE SO COULD SEE THUNDER OUT THAT WAY
BUT FOR NOW GIVEN ISOLATED NATURE EXPECTED LEAVING OUT OF THEIR
TAF.
DURING THE NIGHT THERE WILL BE ANOTHER IMPULSE MOVING FROM KY INTO
WV AND MAY IMPACT BLF/LWB AGAIN SO ADDED SHOWERS BACK IN IN THE
07-09Z TIME FRAME...WHILE CIGS AND VSBYS MAY DROP BEFORE THEN WITH
FOG/STRATUS. THIS MAKING FOR TROUBLESOME TAF FORECAST...AND
CONFIDENCE IS HIGH THAT THE CIGS/VSBYS WILL FLUCTUATE BETWEEN
IFR/LIFR TO VFR AT TIMES THROUGH MORNING GIVEN THE TROPICAL
AIRMASS AND THREAT OF SHOWERS.
FOR TUESDAY THE FRONT SHIFT SOUTHEAST AND TURNS THE WINDS TO THE
WNW. SHOULD CONVECTION IN THE MORNING IN THE WEST TRANSFER EAST OF
THE MOUNTAINS IN THE AFTERNOON. COVERAGE FOR SHOWERS SHOULD BE
50/50 AT LEAST IF NOT MORE BUT KEPT THUNDER OUT OF THE WX GROUP
FOR NOW. AFTER SOME SUB VFR IN THE MORNING...OUTSIDE OF CONVECTION
THERE SHOULD BE VFR CONDITIONS.
THE COLD FRONT...AND ASSOCIATED HIGH PRESSURE...WILL LIKELY BE
STRONG ENOUGH TO PUSH THE TROPICAL AIRMASS OUT OF THE AREA FOR A
COUPLE OF DAYS...BRINGING A GOOD OPPORTUNITY FOR WIDESPREAD VFR
WEATHER THAT MAY LAST OVER MUCH OF THE AREA LATER TUESDAY NIGHT INTO
THURSDAY BEFORE MOISTURE BEGINS TO RETURN NORTHWARD ON THE BACK SIDE
OF THE HIGH LATE IN THE WEEK. ONE EXCEPTION WILL BE AT THE
SOUTHEASTERN WV TERMINAL FORECAST SITES...WHERE RETURN TO VFR
WEATHER WITH NO FLIGHT RESTRICTIONS MAY BE DELAYED UNTIL MID TO LATE
WEDNESDAY DUE TO COOL UPSLOPING WINDS.
&&
.HYDROLOGY...
AS OF 355 PM EDT MONDAY...
WILL ISSUE FLASH FLOOD WATCH IN THE WESTERN COUNTY WARNING AREA
WHERE FLASH FLOOD GUIDANCE IS LOW AND ALONG THE SOUTHERN BLUE
RIDGE THAT HAD HAD POCKETS OF HEAVY RAIN IN THE PAST 24 TO 48
HOURS.
LOCALLY HEAVY RAIN RATES ARE LIKELY AND WITH THE COMBINATION OF
THE SHORT WAVE COMING THROUGH THIS EVENING...THEN THE ADDED
PRECIPITATION OF WITH THE FRONT WILL ENHANCE THE THREAT OF
FLOODING.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR VAZ007-009>017-
032.
NC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR NCZ001>003-018-
019.
WV...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR WVZ042>045.
&&
$$
SYNOPSIS...WERT
NEAR TERM...AMS/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...CF/WP
HYDROLOGY...AMS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
345 PM CDT SUN AUG 11 2013
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM.
A FEW SHOWERS AND THUNDERSTORMS HAVE BEEN PERSISTENT ALONG THE MN/IA
BORDER TODAY. THEY ARE COINCIDENT WITH DEEP LAYER MOISTURE FLUX
CONVERGENCE... 850MB FRONTOGENESIS... WEAK DIFFERENTIAL VORTICITY
ADVECTION... AND UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE
REGION OF THE UPPER JET. THESE FEATURES WILL SLOWLY TRACK EASTWARD
ACROSS SOUTHERN WISCONSIN TONIGHT. IN ADDITION...A DECENT SURFACE
BAROCLINIC ZONE HAS SET UP OVER SOUTHERN WI DUE TO THE EXTENSIVE
CLOUD COVER. THERE IS A TIGHT TEMPERATURE GRADIENT RIGHT ALONG THE
WI/IL BORDER.
THE HRRR AND OTHER MESOSCALE MODELS ARE ALL CURRENTLY OVERDOING THE
PRECIP GOING ON IN IA/MN RIGHT NOW...SO LOW CONFIDENCE IN THEIR
PREDICTION OF WIDESPREAD COVERAGE FOR TONIGHT. NONETHELESS...THERE
IS ENOUGH PERSISTENT FORCING TO HAVE LIKELY SHOWERS AND ISOLATED
THUNDER IN THE FORECAST ACROSS SOUTHERN WI...MAINLY ALONG AND SOUTH
OF I-94...FOR MOST OF THE NIGHT. CHANCES WILL TAPER OFF FROM WEST TO
EAST AFTER MIDNIGHT.
FOG IS LOOKING LIKELY FOR TONIGHT. ORIGINALLY...A COLD FRONT WAS
GOING TO BE DROPPING DOWN TONIGHT...BUT THAT IS LOOKING DELAYED
UNTIL TOMORROW NOW. WINDS WILL BE LIGHT AND THERE IS ADDED LOW LEVEL
MOISTURE FROM THIS MORNING/S RAIN OVER ALL OF SOUTHERN WISCONSIN.
WITH DEWPOINT TEMPS SITTING IN THE LOWER 60S...EXPECTING A SMALL
SPREAD TONIGHT. DENSE FOG WILL BE POSSIBLE...ALTHOUGH THAT WOULD
REQUIRE A PERIOD OF CLEAR SKIES. NOT SURE HOW FAR SOUTH THAT
NORTHERN EDGE OF THE CLOUD SHIELD WILL SINK TONIGHT... SO NOT
CONFIDENT ENOUGH TO ISSUE A DENSE FOG ADVISORY FOR ANY PARTICULAR
AREA AT THIS TIME.
MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
A COLD FRONT WILL DROP DOWN ACROSS SOUTHERN WI ON MONDAY. IT LOOKS
LIKE IT WILL COME IN TWO WAVES...WITH A WEAK SURFACE FRONT WITH
WINDS BECOMING NORTH EARLY MONDAY MORNING...AND THEN A PUSH OF
COLDER AIR LATE MONDAY AFTERNOON. THAT SECOND PUSH IS EXPECTED TO
RUSH DOWN THE LAKE A LITTLE FASTER THAN INLAND...ALSO KNOWN AS A
BACK DOOR COLD FRONT...AND BRING SOME STRONGER WINDS WITH IT.
THERE WILL BE STEEP LOW LEVEL LAPSE RATES AND CYCLONIC FLOW ALOFT
WHICH WILL HELP CLOUDS DEVELOP DURING THE DAY. THERE MAY BE JUST
ENOUGH MOISTURE AROUND IN THE EASTERN MKX FORECAST AREA TO ALLOW FOR
SCATTERED SHOWERS. WHILE THE CHANCE IS SMALL...THERE COULD BE A FEW
RUMBLES OF THUNDER AS WELL. CLOUDS WILL KEEP EASTERN MKX AREA A
LITTLE COOLER IN THE MID 70S...WHILE BREAKS IN THE CLOUDS SHOULD
ALLOW WESTERN AREAS TO WARM UP TO AROUND 80.
.LONG TERM...
MONDAY NIGHT - CONFIDENCE...MEDIUM
SHORT-WAVE TROUGH SWINGS SOUTHEAST THROUGH MY COUNTY WARNING AREA
MONDAY NIGHT. NORMALLY...ONE WOULD THINK OF HAVING AT LEAST A LOW-
CHANCE PROBABILITIES OF MEASURABLE PRECIP WITH A TROUGH.
HOWEVER...MODELS DON/T SHOW MUCH MOISTURE ABOVE 10 THSD FT AGL IN
THE TIME SECTIONS. IN FACT THEY SHOW DRYING TO VARYING DEGREES.
WITH THE LACK OF SATURATION IN THE -10 TO -20C LAYER OF
AIR...CAN/T SEE PRECIPITATION. THE NAM/ECWMF HAVE MY CWA DRY...AND
GFS SPITS OUT A COUPLE SHOWERS. WILL KEEP FORECAST DRY.
TUESDAY THROUGH THURSDAY - CONFIDENCE...MEDIUM
LARGE COOL HIGH PRESSURE DROPS SOUTHEAST TROUGH GREAT LAKES REGION.
QUIET WEATHER. CAN SEE SOME FOG IN RIVER VALLEYS...SO PUT THAT INTO
THE GRID FORECASTS. THE NAM/GFS MODELS SUGGEST ISOLATED SHOWERS
TUESDAY THROUGH THURSDAY WITH HEATING DURING THE DAY. THIS LOOKS TO
TO SOME KIND OF NOISE SINCE THE BUFKIT SOUNDINGS SHOW A PERSISTENT
SUBSIDENCE INVERSION BETWEEN 10 AND 15 THSD FT DURING THIS TIME THAT
CAPS ANY MIXED BOUNDARY LAYER AIR FROM RISING UPWARD. SO WILL KEEP
DRY DURING THIS PERIOD.
FRIDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
GFS SUGGESTS CHANCES FOR PRECIPITATION ON FRIDAY AS A SHORTWAVE
TROUGH AND VORTMAX DROP INTO AND ATTEMPT TO CLOSE OFF OVER SOUTHERN
WISCONSIN. ECMWF IS SIMILAR BUT WEAKER...AND KEEPS THINGS DRY. BOTH
THE GFS AND ECMWF HAVE MID-LEVEL DRY AIR ON FRIDAY...SUGGESTING
MID-LEVEL SUBSIDENCE INVERSION HANGS TOUGH. RATHER THAN YO-YO ON
THE FORECAST...WILL KEEP HOLDING OFF ON CHANCE FOR PRECIPITATION. IT
IS EVEN POSSIBLE THE CLOSING-OFF IDEA WILL OCCUR SOUTH OF WISCONSIN
ANYWAY.
SURFACE HIGH PRESSURE EXTENSION FROM EAST COAST BACK TO ILLINOIS/WI
AREA PER MODEL FORECAST SUGGESTS DRY FOR SATURDAY AND SUNDAY.
&&
.AVIATION/00Z TAFS/...
AN AREA OF SHOWERS WITH A FEW THUNDERSTORMS OVER NORTHERN IOWA WILL
SLOWLY WORK THEIR WAY EASTWARD ACROSS SOUTHERN WI OVERNIGHT. NOT
QUITE CERTAIN ABOUT COVERAGE...BUT THEY SHOULD AT LEAST BE
SCATTERED...IF NOT NUMEROUS. CEILINGS AND VISIBILITIES WILL LOWER
INTO MVFR RANGE WITH AREAS OF FOG AND SCATTERED SHOWERS/THUNDER.
SCATTERED SHOWERS AND ISOLATED THUNDER POSSIBLE ONCE AGAIN MONDAY
AFTERNOON MAINLY EAST OF MADISON WITH A COLD FRONT DROPPING DOWN
ACROSS WISCONSIN.
&&
.MARINE...
A COLD FRONT PUSHES SOUTH MONDAY WITH WINDS TURNING TO THE NORTH AND
THEN NORTHEAST ACROSS LAKE MICHIGAN. PRESSURE RISES ON THE ORDER OF
3 MB/6 HOURS AND DECENT COLD ADVECTION SHOULD KICK UP WINDS AT LEAST
INTO 15 KNOT RANGE. FAVORABLE FETCH MONDAY NIGHT THROUGH TUESDAY
WITH SPEEDS APPROACHING SMALL CRAFT LEVELS SHOULD GENERATE DECENT
WAVES ESPECIALLY FROM MILWAUKEE ON SOUTH. RIGHT NOW LOOKING AT
ABOUT 4 FOOT WAVES LATE MONDAY NIGHT THROUGH TUESDAY AND THESE MAY
LINGER INTO TUESDAY NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...KAPELA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
248 PM CDT SUN AUG 11 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 248 PM CDT SUN AUG 11 2013
MAIN FORECAST CONCERNS ARE ON PRECIPITATION TONIGHT AND DENSE FOG
POTENTIAL TONIGHT INTO MONDAY MORNING.
CURRENTLY...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER
MUCH OF THE U.S. AND CANADIAN ROCKIES...WHILE TROUGHING DOMINATED
SOUTHEAST CANADA. THE FORECAST AREA RESIDES IN WEST-NORTHWEST
FLOW...WITH SHORTWAVES OF NOTE OVER NORTHEAST IOWA...SOUTHERN
MANITOBA AND A MUCH STRONGER ONE OVER NORTHERN MANITOBA. THE
NORTHEAST IOWA SHORTWAVE...COMBINED WITH A LOW TO MID LEVEL
FRONTOGENESIS ZONE AND A RIGHT ENTRANCE REGION OF AN 80 KT UPPER
JET STREAK IN NORTHERN WI...HAS HELPED TO KEEP SOME SHOWER
ACTIVITY GOING ACROSS NORTHERN IOWA THROUGH THE AFTERNOON. ALSO
PLENTY OF CLOUDS EXIST ACROSS THE FORECAST AREA...RESULTING FROM
DEEP LOW LEVEL MOISTURE SEEN ON THE 12Z MPX SOUNDING AND THE LACK
OF MUCH WIND FLOW TO ADVECT DRIER AIR SEEN ACROSS NORTH DAKOTA AND
NORTHERN MN. THE DRIER AIR LIES BEHIND A SURFACE TROUGH STRETCHING
FROM EASTERN NEBRASKA INTO NORTHWEST WI. A FEW SHOWERS HAVE FORMED
ON THIS TROUGH ACROSS EAST CENTRAL MN. FARTHER SOUTH...A WARM
FRONT ENHANCED BY OUTFLOW FROM THE SHOWERS WAS PRESENT STRETCHING
ALONG US-20 IN IOWA.
SYNOPTIC OVERVIEW...
FOCUS IS MOSTLY ON THE SHORTWAVE OVER NORTHERN MANITOBA. MODELS PROG
THIS SHORTWAVE TO DROP SOUTHEAST INTO UPPER MICHIGAN ON MONDAY. THIS
SHORTWAVE ALLOWS UPPER TROUGHING TO MOVE INTO THE FORECAST AREA...
AND SIMULTANEOUSLY HELPS GIVE THE SURFACE TROUGH IN MN A PUSH
SOUTHEAST. BY 12Z MONDAY...THE TROUGH...LIKELY NOW A COLD
FRONT...SHOULD BE SOUTHEAST OF THE AREA. THERE ARE ALSO
INDICATIONS OF AN INVERTED SURFACE TROUGH LINGERING BACK EXTENDING
NORTHWEST TO SOUTHEAST OVER CENTRAL/EASTERN WI...ASSOCIATED WITH
THAT SHORTWAVE DROPPING INTO UPPER MI.
HAZARDS...
DENSE FOG CONCERNS TONIGHT GIVEN RECENT RAINS...LIGHT WINDS...LATE
DAY CLEARING AND SMALL TEMP/DEWPOINT SPREADS ALREADY.
DETAILS...
SHOWERS IN EAST CENTRAL MINNESOTA MAY TRY TO DROP DOWN INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA THIS EVENING.
HOWEVER...THEY ARE HIGHLY DIURNALLY DRIVEN...THUS ONCE HEATING
ENDS THEY SHOULD FALL APART QUICKLY. INCLUDED SOME 20 PERCENT
CHANCES FOR THEM FOR A FEW HOURS THIS EVENING. MEANWHILE...TO THE
SOUTH...ONGOING SHOWERS AND STORMS ACROSS NORTHEAST IOWA MAY
PERSIST THROUGH MUCH OF THE EVENING...SUPPORTED BY THE SHORTWAVE
TRACKING ACROSS NORTHEAST IOWA...THE LOW/MID LEVEL F-GEN AND RIGHT
ENTRANCE REGION. HOWEVER...AS THE UPPER FLOW TURNS MORE
NORTHWESTERLY... ANTICIPATING THESE FORCING FEATURES TO DROP
SOUTHEAST AND HELP DIMINISH THE PRECIPITATION. DID KEEP 20-40
PERCENT CHANCES GOING AFTER MIDNIGHT JUST IN CASE PRECIP HOLDS
ON A BIT LONGER THAN EXPECTED.
CONCERN THEN SHIFTS TO FOG GIVEN RECENT RAIN. CLOUDS OVER THE
FORECAST AREA...PARTICULARLY OVER THE NORTHERN HALF...SHOULD CLEAR
OUT THIS EVENING. WINDS LOOK TO STAY FAIRLY LIGHT THROUGH THE
NIGHT...EVEN AFTER THE TROUGH/FRONTAL PASSAGE. ITS WORTH NOTING
THAT WINDS DO PICK UP AT 950MB INTO THE 10-20 KT RANGE BY 12Z...
HOWEVER...THESE ARE ABOVE A 3C FRONTAL INVERSION. THUS...THEY SHOULD
NOT IMPACT THE FOG POTENTIAL MUCH. IN FACT...11.00Z/06Z/12Z HIRES
ARW/NMM AND 11.09Z SREF VISIBILITY PROGS SHOW PRETTY MUCH A SOLID
AREA OF FOG OVER SOUTHEAST MN...NORTHERN PARTS OF IOWA AND MUCH OF
SOUTHERN WI. ADDED MENTION OF FOG EARLIER ACROSS MUCH OF THE
FORECAST AREA...AND NOW HAVE RAISED THE COVERAGE TO WIDESPREAD IN A
CORRIDOR FROM SOUTHEAST MINNESOTA EAST INTO JACKSON...JUNEAU...ADAMS
AND VERNON COUNTIES OF WI. THIS AREA HAS ALSO BEEN INCLUDED IN A
DENSE FOG ADVISORY...SINCE FROM A REGIONAL PERSPECTIVE SEEMS TO
HAVE THE HIGHEST PROBABILITY OF METEOROLOGICAL CONDITIONS
FAVORABLE FOR DENSE FOG. THE ADVISORY MAY HAVE TO BE EXPANDED
SOUTH...ESPECIALLY IF SKIES END UP CLEARING THERE.
FOR MONDAY...COOLER AIR ALOFT UNDER THE UPPER TROUGHING COMBINED
WITH THE INVERTED SURFACE TROUGH...DAYTIME HEATING AND LINGERING LOW
LEVEL MOISTURE SHOULD ALLOW FOR ISOLATED/SCATTERED SHOWERS TO FORM
ALONG/NORTHEAST OF I-94. MLCAPE VALUES ALONG THE INVERTED TROUGH ARE
IN THE 100-300 J/KG AT 18Z...ENOUGH MAYBE TO GET A FEW
THUNDERSTORMS. BETTER INSTABILITY IS OFF TOWARDS SOUTHEAST WI WITH
HELP FROM LAKE BREEZE CONVERGENCE. ONCE THE FOG AND ASSOCIATED LOW
STRATUS MIX OUT A FEW HOURS AFTER SUNRISE...RELATIVELY BREEZY
NORTHWEST WINDS APPEAR TO SET UP. 850MB TEMPS IN THE 10-14C RANGE
SUPPORT HIGHS IN THE MID 70S TO LOW 80S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 PM CDT SUN AUG 11 2013
MUCH OF THE ENTIRE LONG TERM PERIOD IS DOMINATED BY RIDGING OVER THE
WESTERN U.S. AND TROUGHING IN THE EASTERN U.S....A POSITIVE PNA
PATTERN THAT RESULTS IN COOLER AND DRIER THAN NORMAL WEATHER. AT THE
SURFACE...CANADIAN HIGH PRESSURE IS PROGGED TO BUILD INTO THE AREA
MONDAY NIGHT AND TUESDAY...SIT OVER THE AREA TUESDAY NIGHT THROUGH
WEDNESDAY...THEN ONLY SLOWLY DRIFT OFF TOWARDS THE EASTERN GREAT
LAKES THIS WEEKEND. DRY AIR ACCOMPANYING THE HIGH LOOKS TO KEEP THE
BULK OF THE LONG TERM PERIOD DRY. IN FACT...PRECIPITABLE WATER
VALUES ARE FORECAST BETWEEN 50-70 PERCENT OF NORMAL FOR TUESDAY
THROUGH THURSDAY. THIS SHOULD RESULT IN DECENT MIXING OF DEWPOINTS
DURING THE AFTERNOONS.
THE ONLY FEATURE REALLY OF INTEREST FOR POTENTIAL PRECIPITATION IS A
SHORTWAVE TROUGH THAT DROPS DOWN THROUGH THE NORTHWEST FLOW INTO THE
AREA THURSDAY NIGHT AND FRIDAY. BOTH THE 11.12Z GFS/CANADIAN PRODUCE
SOME LIGHT PRECIPITATION WITH IT OVER WESTERN AND NORTHERN SECTIONS
OF THE FORECAST AREA...WHEREAS THE 11.00Z/11.12Z ECMWF IS DRY. FROM
A CONSENSUS STANDPOINT...HAVE CONTINUED TO CARRY A 20 PERCENT CHANCE
TO ACCOUNT FOR THE GFS/CANADIAN. HOWEVER...LATER FORECASTS WILL BE
ABLE TO GO DRY IF THE GFS/CANADIAN TREND TOWARDS THE ECMWF.
TEMPERATURE WISE...850MB TEMP ANOMALIES ARE PROGGED TO BOTTOM OUT
BETWEEN 1-1.5C BELOW NORMAL FOR TUESDAY AND WEDNESDAY...READINGS OF
8C EAST TO 10C WEST. THUS THIS WILL BE THE COLDEST PERIOD WITH HIGHS
IN THE 70S. LOWS ARE LIKELY GOING TO DIP INTO THE 40S AT THE TYPICAL
COLD SPOTS TUESDAY NIGHT AND WEDNESDAY NIGHT WITH THE HIGH
OVERHEAD...WHICH WILL ALSO BE THE MOST FAVORABLE TIME PERIODS FOR
VALLEY FOG. VALLEY FOG IS ALSO POSSIBLE MONDAY NIGHT...BUT WINDS
WITH THE INCOMING HIGH MAY RESTRICT SOME OF THE COVERAGE. SLOW
WARMING OF 850MB TEMPS AND ANOMALIES IS FORECAST FOR THURSDAY AND
BEYOND...PEAKING AT 12C EAST TO 15C WEST AND AROUND NORMAL FOR
ANOMALY BY SUNDAY. THUS TEMPERATURES SHOULD SLOWLY CLIMB TOO EACH
DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM CDT SUN AUG 11 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS
THE AREA THIS AFTERNOON INTO EARLY THIS EVENING. THE BULK OF THIS
ACTIVITY WILL OCCUR SOUTH OF INTERSTATE 90...WITH ISOLATED
SHOWERS POSSIBLE AT THE TAF SITES. PLAN ON MVFR CEILINGS AT TIMES
THIS AFTERNOON WITH CLOUD BASES AROUND 1500 FT. CLEARING IS
EXPECTED TO OCCUR FROM THE NORTHWEST TONIGHT AS DRIER AIR MOVES
IN ALOFT. THIS WILL SET THE STAGE FOR DENSE FOG AT THE TAF SITES.
THE ONLY NEGATIVE GOING FOR DENSE FOG IS THE POTENTIAL FOR SOME
LINGERING CLOUDS OVER THE AREA OVERNIGHT. LIFR CONDITIONS ARE
EXPECTED AFTER MIDNIGHT TONIGHT IN DENSE FOG AT BOTH TAF SITES
WITH VISIBILITIES FALLING TO 1/4 MILE OR LESS AT TIMES. THE FOG
SHOULD MIX OUT IN THE 13 TO 14Z TIMEFRAME WITH VFR CONDITIONS
EXPECTED BY THE MID TO LATE MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY FROM 3 AM TO 9 AM CDT MONDAY FOR WIZ032>034-
041>044-053.
MN...DENSE FOG ADVISORY FROM 3 AM TO 9 AM CDT MONDAY FOR MNZ079-
086>088-094>096.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1235 PM CDT SUN AUG 11 2013
.UPDATE...
FIRST WAVE OF LIGHT RAIN ASSOCIATED WITH A SHORTWAVE TROUGH HAS
SHIFTED INTO THE NORTHEAST MKX FORECAST AREA LATE THIS MORNING.
ANOTHER AREA OF SHOWERS WITH A FEW RUMBLES OF THUNDER ALONG THE
MN/IOWA BORDER HAS BEEN MOVING EAST WITH A VERY WEAK SHORTWAVE WITH
SOME SUPPORT FROM DIVERGENCE ALOFT DUE TO A RIGHT ENTRANCE REGION OF
THE UPPER JET. THE LEADING EDGE OF THAT PRECIP IS DISSIPATING AS IT
GETS INTO SOUTHWEST WI...BUT THE BACK EDGE OF IT HAS SUPPORT FROM
850MB FRONTOGENESIS.
THE 15Z HRRR AND 12Z WRF-ARW AND WRF-NMM SHOW THE SOUTH CENTRAL
MN/NORTH CENTRAL IOWA PRECIP TO EXPAND ACROSS SOUTHERN WI THIS
AFTERNOON. THEIR INITIALIZATION LOOKS OVERDONE...SO WILL KEEP THE
LOWER POPS /SCATTERED/ MENTION THROUGH THE AFTERNOON. WEAK
INSTABILITY ALLOWS FOR THUNDER POSSIBILITY.
TEMPS WILL STAY PRETTY COOL TODAY DUE TO THE CLOUD COVER. GOING MAX
TEMPS IN THE LOWER 70S LOOKS ON TRACK.
ONE MORE SHORTWAVE TROUGH DROPS THROUGH THE UPPER MIDWEST THIS
EVENING...ALONG WITH A WESTERLY LOW LEVEL JET AND WEAK UPPER
DIVERGENCE. THEREFORE...NOT GIVING UP ON THE POSSIBILITY FOR ANOTHER
ROUND OF SHOWERS WITH ISOLATED THUNDER THIS EVENING...BUT CONFIDENCE
IS LOW.
&&
.AVIATION/18Z TAFS/...
SHOWERS AND THUNDERSTORMS WILL BE A SMALL THREAT FOR THE AFTERNOON.
THE PRECIP MOVING INTO SOUTHWEST WI NOW IS DISSIPATING.
THERE IS LOWER CONFIDENCE ON HOW THE EVENING PRECIP WILL PAN OUT. IT
MAY BE MORE SCATTERED SHOWERS WITH A FEW THUNDERSTORMS NOW INSTEAD
OF WIDESPREAD SHOWERS AND THUNDERSTORMS. CEILINGS AND VISIBILITIES
WILL LOWER INTO MVFR RANGE PATCHY FOG AND THREAT FOR SHOWERS/THUNDER.
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT SUN AUG 11 2013/
TODAY-FORECAST CONFIDENCE MEDIUM
INITIAL SHORT WAVE TROUGH MOVING THROUGH WITH 20 METER HEIGHT FALLS
EARLY THIS MORNING AND SHOULD BE OVER THE EASTERN GREAT LAKES BY THE
AFTERNOON. COMPLEX DOUBLE UPPER JET STRUCTURE DIFFICULT TO INTERPRET
FORCING DURING THE DAY WITH ONE BRANCH ACROSS LAKES INTO SOUTHERN
QUEBEC AND THE OTHER FROM OHIO VALLEY INTO SOUTHERN NEW ENGLAND.
LOW LEVEL JET IS WEAK AND VEERS TO DUE WEST DURING THE DAY AT ABOUT
20 KNOTS FROM NORTHERN IOWA INTO SOUTHERN WISCONSIN.
ACTIVE CONVECTION FARTHER FAR WEST AND MOST SHORT RANGE AND
MESOSCALE MODEL GUIDANCE KEEPS IT THAT WAY DURING THE DAY. MOSTLY
ANVIL DEBRIS MAKING INTO SOUTHERN WISCONSIN BEFORE LATE AFTERNOON SO
WILL WAIT UNTIL AFTER 18Z TO INTRODUCE THUNDER.
CLOUDS AND PRECIPITATION SHOULD HOLD READINGS DOWN WITH MOST
LOCATIONS STRUGGLING TO REACH THE MIDDLE 70S.
TONIGHT-FORECAST CONFIDENCE HIGH
DEEP UPPER LOW MOVES ACROSS JAMES BAY WITH ASSOCIATED TROUGH DIGGING
SOUTH ACROSS ONTARIO. WIDESPREAD HEIGHT FALLS OF 20 TO 60 METERS
SPREAD OVER GREAT LAKES AS COLD FRONT PUSHES INTO CENTRAL
WISCONSIN. 90 KNOT 250 MB JET MOVES ACROSS LAKE HURON WITH RIGHT
ENTRANCE REGION OVER SOUTHERN WISCONSIN. 850 MB JET INCREASES TO
ABOUT 30 KNOTS OVER SOUTHERN LAKE MICHIGAN DURING THE NIGHT WITH
DECENT WARM ADVECTION AT LOW LEVELS. THUS...APPEARS THAT
THUNDERSTORMS WILL IMPACT MOST OF SOUTHERN WISCONSIN AND ESPECIALLY
SOUTHERN TWO TIERS.
TOUGH TO GET OVERLY EXCITED ABOUT SEVERE POTENTIAL DESPITE DECENT
SHEAR. MODELS HAVE MARGINAL INSTABILITY SO APPEARS THAT LARGE
CONVECTIVE BLOB MOVES THROUGH WITH MARGINAL WIND AND HAIL THREAT PER
SPC OUTLOOK.
MONDAY - CONFIDENCE...MEDIUM
LINGERING SURFACE/850 TROUGH IN THE SE RESULTS IN SHRA CHANCES
ESPECIALLY DURING THE MORNING HOURS. FRONTOGENETICAL FORCING IS WEAK
AND SO IS THE Q-VECTOR CONVERGENCE. RENEWED SHORTWAVE ENERGY ARRIVES
LATER IN THE AFTERNOON WITH AN UPTICK IN FORCING. HOWEVER LOW LEVEL
COLD ADVECTION STARTING TO KICK IN AS WELL. NAM AND GFS BOTH SHOW
LIGHT QPF IN THE 18-00Z TIME FRAME ESPECIALLY IN NE CWA. BUFKIT
SOUNDINGS SHOW CAPE DEVELOPING IN THE AFTERNOON. WILL MAINTAIN THE
GOING CHANCE FOR TSRA POPPING UP IN THE WAKE OF MORNING FRONTAL TYPE
PRECIP.
TUESDAY - CONFIDENCE...MEDIUM
COOLER AIRMASS WITH NE WINDS AND 850 THERMAL TROUGH EXTENDING INTO
ERN WI. YET ANOTHER SHORTWAVE WRAPS INTO WI IN THE NORTHWEST FLOW.
MUCH ONLY THE NAM GENERATES PRECIP WITH OTHER MODELS KEEPING THE
DRIER AIRMASS DOMINANT. THE ECMWF SHOWS DEW POINTS DROPPING INTO THE
U40S/L50S WHICH SEEMS PLAUSIBLE AND WOULD LIMIT THE INSTABILITY.
BUFKIT SOUNDINGS FROM BOTH THE NAM AND GFS SUGGEST COLUMN TOO DRY TO
SUPPORT ANY PRECIP. WILL KEEP FORECAST DRY PER ECMWF/GFS MOS DESPITE
THE FORMIDABLE LOOK TO THE 500 MILLIBAR SHORTWAVE AND SMALLISH POPS
FROM THE NAM.
WEDNESDAY THROUGH SATURDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE WILL BE DOMINANT THIS PERIOD WITH QUIET CONDITIONS.
925 TEMPS COOLEST WEDNESDAY WITH VERY SLOW MODIFICATION INTO
SATURDAY. INFLUENCE OF HIGH KEEPING PRECIP POTENTIAL NEAR NIL. GFS
IS THROWING OUT SOME PRECIP SPLOTCHES HERE AND THERE THOUGH
LEANING TOWARDS THE DRY LOOK OF THE ECMWF.
AVIATION/12Z TAFS/...VFR CONDITIONS EXPECTED MUCH OF THE PERIOD.
PATCHY MVFR FOG MAINLY KENW AREA FIRST THING SHOULD NOT LINGER
VERY LONG. DEBRIS CLOUDS SPREADING IN FROM THUNDERSTORM COMPLEX
ALONG IOWA/MINNESOTA BORDER EARLY TODAY AND SHOULD LINGER INTO
MONDAY.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT FOR NEXT 24 HOURS OR MORE
BUT ESPECIALLY TONIGHT. MOST OF THE ACTIVITY DURING THE DAY SHOULD
BE RELATIVELY LIGHT AND NOT HAVE MUCH IMPACT ON CEILINGS AND
VISIBILITIES. CEILINGS AND VISIBILITIES WILL LOWER INTO MVFR RANGE
FOR A WHILE TONIGHT WITH PERSISTENT PRECIPITATION AND LOCALLY
HEAVIER SHOWERS.
MARINE...COLD FRONT PUSHES SOUTH MONDAY WITH WINDS TURNING TO THE NORTH
AND THEN NORTHEAST ACROSS LAKE MICHIGAN. PRESSURE RISES ON THE ORDER
OF 3 MB/6 HOURS AND DECENT COLD ADVECTION SHOULD KICK UP WINDS AT LEAST
INTO 15 KNOT RANGE. FAVORABLE FETCH MONDAY NIGHT THROUGH TUESDAY WITH
SPEEDS APPROACHING SMALL CRAFT LEVELS SHOULD GENERATE DECENT WAVES
ESPECIALLY FROM MILWAUKEE ON SOUTH. RIGHT NOW LOOKING AT ABOUT 4
FOOT WAVES LATE MONDAY NIGHT THROUGH TUESDAY AND THESE MAY LINGER
INTO TUESDAY NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...COLLAR
MONDAY THROUGH SATURDAY...CRAVEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1141 PM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 949 PM CDT SAT AUG 10 2013
CONTINUE TO MONITOR CONVECTIVE TRENDS FOR THE OVERNIGHT PERIOD AS
A SYSTEM MOVES INTO THE REGION. CURRENTLY...SHOWERS HAVE FIZZLED
ACROSS SOUTHERN MINNESOTA AS AN INITIAL MID LEVEL SHORTWAVE TROUGH
HAS WEAKENED AS IT HAS TRACKED EAST TOWARD THE MISSISSIPPI RIVER.
THE STRONGER LIFT IS STILL WELL BACK TO THE WEST ALONG TWO
SEPARATE FEATURES...A FRONTOGENETIC BAND IN SOUTHEAST SOUTH DAKOTA
AND A MID LEVEL SHORT WAVE TROUGH IN NORTH DAKOTA. THE PAST FEW
RUNS OF THE HRRR AND RAP HAVE BROUGHT SOME OF THE SCATTERED LIGHT
RAIN SHOWERS INTO THE REGION THROUGH THE NEXT 6 HOURS OR SO...BUT
DO NOT EXPECT MUCH IF ANYTHING OUT OF THESE. THE MAIN SHOW WILL
COME IN INITIALLY WITH THE BAND OF FRONTOGENESIS THAT HAS HELPED
CONVECTION DEVELOP IN SOUTHEAST SOUTH DAKOTA ALONG A SURFACE WARM
FRONT. THIS BAND IS GOING TO VERY SLOWLY DRIFT EAST OVERNIGHT AND
MAY NOT REACH THE REGION UNTIL LATER IN THE MORNING. THIS LEADS TO
SOME QUESTIONS ABOUT HOW MUCH WILL BUILD IN AHEAD OF IT AS LOW
LEVEL MOISTURE TRANSPORT DOES TRY TO INCREASE FROM THE SOUTHWEST.
BASED ON THIS...WILL HAVE TO BACK OFF ON THE PRECIPITATION CHANCES
A LITTLE OVERNIGHT BUT WILL KEEP THEM ON THE HIGHER SIDE TOMORROW
MORNING AND AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 347 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE ON SHOWERS AND THUNDERSTORMS LATE TONIGHT
THROUGH SUNDAY NIGHT.
LATEST WATER VAPOR IMAGERY SHOWED WEST/NORTHWEST FLOW ALOFT ACROSS
THE REGION. TWO MAIN SHORTWAVES TO FOCUS ON OVER THE NEXT 36
HOURS...A LEADING WAVE OVER EASTERN SOUTH DAKOTA AND
ANOTHER VIGOROUS SHORTWAVE OVER SOUTHERN SASKATCHEWAN DIGGING
SOUTHEAST INTO WESTERN NORTH DAKOTA. SHOWERS AND EMBEDDED
THUNDERSTORMS WERE OCCURRING OVER EASTERN AND NORTH CENTRAL SOUTH
DAKOTA. AN ADDITIONAL AREA OF SHOWERS AND STORMS WERE ERUPTING
OVER EXTREME NORTHWEST MONTANA AND NORTHWESTERN NORTH DAKOTA.
THE SHORTWAVE OVER EASTERN SOUTH DAKOTA WILL MAKE ITS WAY EAST INTO
THE FORECAST AREA LATE THIS EVENING. MEANWHILE...THE NORTHERN
SHORTWAVE WILL BE PUSHING SOUTHEAST INTO THE REGION AS A 250MB JET
STREAK INTENSIFIES AND SAGS SOUTH...PLACING THE RIGHT ENTRANCE REGION
OVER CENTRAL MINNESOTA/INTO CENTRAL WISCONSIN. A FRONTAL BOUNDARY
WILL ORIENT ITSELF RIGHT ALONG THE INTERSTATE 90 CORRIDOR LATE THIS
EVENING INTO THE OVERNIGHT HOURS AND PROVIDE THE FOCUS FOR SHOWER
AND THUNDERSTORMS DEVELOPMENT. THINKING A COMPLEX OF SHOWERS AND
STORMS SHOULD INTENSIFY OVER SOUTHEAST SOUTH DAKOTA/SOUTHWEST
MINNESOTA/NORTHWEST IOWA...THEN PUSH EAST INTO THE FORECAST AREA LATE
TONIGHT INTO EARLY SUNDAY MORNING. THERE IS A GENERAL INCREASE IN
MOISTURE TRANSPORT INTO THE FRONT OVERNIGHT INTO SATURDAY
MORNING AND A RATHER IMPRESSIVE INCREASE IN FRONTOGENESIS
ESPECIALLY IN THE NAM. WHILE THE NAM APPEARS TO BE CONTAMINATED BY
SOME CONVECTION...THINKING IT HAS THE RIGHT IDEA WITH AN INCREASE
IN FRONTOGENESIS IN THE 9 TO 15Z TIME FRAME. ADDITIONAL SHOWER AND
POSSIBLY SCATTERED THUNDERSTORM DEVELOPMENT IS LIKELY AHEAD OF THE
MAIN COMPLEX OF STORMS WORKING INTO THE AREA FROM THE WEST
TONIGHT. PLAN ON SHOWERS AND STORMS TO SPREAD INTO AREAS WEST OF
THE MISSISSIPPI RIVER AFTER MIDNIGHT THEN WORKING EAST INTO
CENTRAL AND SOUTHWEST WISCONSIN AROUND DAYBREAK SUNDAY MORNING.
SOME HEALTHY RAINFALL AMOUNTS IN STORE FOR LOCATIONS ALONG AND
SOUTH OF INTERSTATE 90...WHERE RAINFALL COULD TOTAL 1/2 INCH TO
NEARLY ONE INCH DEPENDING ON EXACTLY WHERE THE BAND SETS UP. THE
BAND OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL PERSIST OVER
THE AREA THROUGH THE MORNING HOURS AND INTO SUNDAY AFTERNOON THEN
SHOULD GRADUALLY START TO SHIFT SOUTHWARD. THE ABUNDANT CLOUD
COVER AND ONGOING SHOWERS AND STORMS WILL HELP LIMIT HOW MUCH
INSTABILITY BUILDS THROUGH THE DAY AND WILL ALSO ACT TO KEEP
TEMPERATURES ON THE COOL SIDE WITH HIGHS ONLY IN THE LOWER 70S. IN
FACT...LOCATIONS RIGHT UNDER THE BAND WILL STRUGGLE TO GET OUT OF
THE 60S. IF THERE HAPPENS TO BE A BREAK IN THE ACTIVITY FROM MID
SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON AND ENOUGH INSTABILITY
CAN BUILD ALONG THE FRONTAL BOUNDARY THERE IS AN OUTSIDE CHANCE OF
A STRONGER THUNDERSTORM OVER NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. THE OVERALL PROBABILITY OF THIS OCCURRING OVER THESE
AREA APPEARS LOW AT THIS TIME...BUT WILL HAVE TO KEEP A CLOSE EYE
ON CLOUD/PRECIPITATION TRENDS. FORECAST MODELS ATTEMPT TO INCREASE
THE INSTABILITY RIGHT ALONG THE BOUNDARY SUNDAY AFTERNOON OVER
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN WITH MLCAPE VALUES
CLIMBING TO AROUND 1100 J/KG. 0-6KM BULK SHEAR VALUES HOVERING
AROUND 40 KTS WOULD BE SUFFICIENT FOR A SEVERE STORM OR TWO. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS. ALSO...WILL
HAVE TO KEEP A CLOSE EYE ON ANY STORMS THAT WOULD DEVELOP RIGHT
ALONG THE BOUNDARY WHERE SHEAR PROFILES COULD POSSIBLY SUPPORT A
TORNADO. ALL OF THIS IS CONDITIONAL ON AFTERNOON DESTABILIZATION.
ONGOING SHOWERS AND STORMS WILL GRADUALLY TAPER OFF SUNDAY EVENING
INTO LATE SUNDAY NIGHT AS THE BOUNDARY SLIPS SOUTH AND THE JET
STREAK WEAKENS SLIGHTLY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 347 PM CDT SAT AUG 10 2013
SHOWERS AND STORMS TAPER OFF SUNDAY NIGHT THEN ANOTHER TROUGH DIVES
SOUTH OUT OF CANADA AND INTO THE UPPER MISSISSIPPI RIVER VALLEY
MONDAY AFTERNOON INTO TUESDAY. THIS FEATURE MAY GENERATE A FEW
SHOWERS AND ISOLATED STORMS AS IT MOVES THROUGH...PARTICULARLY OVER
NORTH CENTRAL WISCONSIN. CANADIAN HIGH PRESSURE THEN BUILDS INTO THE
AREA TUESDAY THROUGH THURSDAY WITH DRY AND QUIET CONDITIONS
EXPECTED. WILL HAVE TO KEEP A CLOSE EYE ON THE POTENTIAL FOR VALLEY
FOG WITH THE HIGH OVERHEAD AND LIGHT WINDS. PLAN ON SEASONABLY COOL
TEMPERATURES THROUGH THE THE WEEK WITH HIGHS IN THE MID TO UPPER
70S. RAIN CHANCES RETURN THURSDAY NIGHT THROUGH FRIDAY NIGHT AS
WEAK SHORTWAVES MOVE THROUGH THE REGION. HOWEVER...LATEST MODEL
GUIDANCE HINTS AT THIS TIME FRAME POSSIBLY ENDING UP DRY. IF MODEL
TRENDS CONTINUE PRECIPITATION CHANCES MAY NOT BE NEEDED DURING
THIS TIME FRAME WITH THE SURFACE HIGH HOLDING STRONG FROM THE
MIDDLE OF NEXT WEEK ALL THE WAY INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM CDT SAT AUG 10 2013
SHOWERS AND A FEW THUNDERSTORMS ARE TRACKING EAST ACROSS SOUTHERN
MINNESOTA AND WILL BECOME MORE WIDESPREAD THROUGH SUNDAY MORNING.
SOME MVFR CONDITIONS ARE POSSIBLE AS THE MORNING PROGRESSES AND
THE RAIN PERSISTS. WHILE SOME SCATTERED LIGHT RAIN SHOWERS ARE
DEVELOPING NEAR RST...THE MAIN CLUSTER OF SHOWERS AND
THUNDERSTORMS WILL MOVE INTO RST AROUND 8Z AND LSE AROUND 10Z.
THIS RAIN COULD HANG OUT ACROSS THE REGION THROUGH MUCH OF THE
MORNING AND PERHAPS INTO THE EARLY AFTERNOON AS THIS SYSTEM MOVES
THROUGH. IF SOME THUNDERSTORMS DEVELOP...CAN NOT RULE OUT SOME IFR
CONDITIONS DEVELOPING FOR A BRIEF PERIOD. OTHERWISE...EXPECT THAT
CONDITIONS WILL IMPROVE INTO SUNDAY EVENING AS THE SYSTEM DROPS TO
THE SOUTHEAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
427 AM EDT Tue Aug 13 2013
.NEAR TERM [Today and Tonight]...
As has been quite typical during this very unusual summer, it has
been nearly impossible to keep an established upper level ridge in
place across the SE U.S. So, while on Monday, many areas experienced
an extended period (during the day) of hot and dry conditions with
many high temps in the mid to upper 90s, today is expected to be our
transition back to a wet and trough dominated pattern. Although
the more significant cooler and wetter weather will likely be
reserved for Wednesday and onward for the next several days at
least, PoPs will clearly be on the increase from NW to SE over the
CWA today. Max temps may still reach the lower 90s to the west and
the middle 90s well to the east, but by this afternoon, PoPs are
expected to reach the likely category (60-70% with locally heavy
rainfall likely) across the FL Panhandle, SE AL, and the NW 1/3 of
our GA zones, and PWATs will be back on the increase with many
other favorable factors in place to initiate convection.
Elsewhere, the PoPs are expected to gradually taper off from NW to
SE, with 50s and 40s over the remainder of our GA zones, then
finally down to the 40% to 20% range across the remainder of the
FL Big Bend, so with this much variation, mesoscale updates will
likely be needed to the fcst today, with heavy weighting given to
the Hi-Res Models (including our local and NCEP`s WRF runs, and
the HRRR (High Resolution Rapid Refresh). Tonight`s fcst could be
even more complex in terms of PoPs and timing, so leaned heavily
on a combination of our CAM (Convective Allowing Model) output and
locally generated confidence grids.
&&
.SHORT TERM [Wednesday through Thursday]...
There remains high confidence in widespread rain coverage for the
short term period (Wednesday to Thursday). The ingredients include
a stalling low-level front, a weak upstream trough in the mid-
upper levels of the atmosphere, and a plume of deep moisture. The
NAM, GFS, and ECMWF all show widespread rainfall in this 36-hour
period of around an inch, with locally higher amounts. Therefore,
PoPs were pushed above model guidance again - with widespread
"likely" (60-70%) values during the daytime hours, and high chance
(40-50%) at night. This equates to rain chances roughly 20-30%
above climatology during the entire period. Given very weak flow
(and thus slow storm motions) and high PWATs, the environment
should support locally heavy rainfall. Heavy rain wording was once
again included in the forecast. Given the abundance of rain and
clouds, high temperatures were kept slightly below the model
consensus, and low temperatures slightly above consensus.
&&
.LONG TERM [Thursday Night through Monday]...
A long wave trough will remain in place from the Great Lakes to the
central Gulf Coast early in the period as a reinforcing short wave
in the northern plains drops into the trough, resulting in a closed
low over the Lower Mississippi Valley by Saturday. This low
gradually fills and weakens, leaving behind a weak trough for early
next week with an axis still to our west.
The end result is a prolonged period of rain for the southeast with
periods of heavy rain likely. Total rainfall from the GFS indicates
areas of rain up to 10 inches across the FL panhandle through
Monday, due in part to its development of a tropical cyclone in the
gulf which it brings into the FL panhandle Saturday. The Canadian
also generates a tropical system similar to the GFS, however the
ECMWF does not generate a tropical system and therefore depicts
rainfall totals through Monday of about 5 inches.
Confidence of a period of heavy rain is high, and if the
GFS-advertised tropical system does develop then local rainfall
amounts could be double or triple the current WPC 5.5" totals.
&&
.AVIATION [through 12 UTC Wednesday]...
VFR conditions are expected to prevail for the remainder of the
overnight hours tonight (with the possible exception of MVFR CIGS
at ECP), but the greater concern as we move forward with time will
be the increasing probabilities and coverage of showers and
thunderstorms across the terminals. Initially, the most
pessimistic flying conditions will be at the northern and western
terminals (DHN, ECP, and ABY), but MVFR/IFR restrictions will
likely spread eastward towards TLH and VLD along with the
convection later this afternoon and evening. However, when all is
said and done, the most challenging portion of the fcst will
likely be between 06 and 12 UTC on Wed., where if there is a
significant break in the convection and residual mid and upper
level clouds, very low CIGS and or vis could develop and become
problematic.
&&
.MARINE...
A gradual increase in the pressure gradient over the next few days
should cause winds to increase from the 5-10 knot range more into
the 10-15 knot range, with perhaps a slight increase in seas. We
will be keeping an eye on the western Caribbean and southern Gulf
of Mexico for tropical development in the next five days. The NHC
has posted a "low chance" of development for those areas, and
therefore we mentioned this possibility in the CWF text.
&&
.FIRE WEATHER...
ed flag conditions are not expected over the next several days, as
wet and more humid weather will make a quick return to the region.
&&
.HYDROLOGY...
Widespread rainfall totals of at least 3 inches appear likely over
the next week, which will likely cause an increase in flows on
area rivers - particularly after Thursday. The vast majority of
rivers and creeks in the area are below bankfull levels thanks to
a relatively dry period in the past week or so. Therefore, it will
likely take a few days worth of heavy rainfall to cause more
widespread increases in the flows on area rivers. It is too early
to determine flooding potential on specific rivers, as that will
ultimately hinge on the location and intensity of the heaviest
rainfall.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 93 75 91 75 89 / 40 30 60 50 70
Panama City 90 78 88 77 86 / 50 60 60 50 70
Dothan 92 74 87 74 87 / 70 30 70 50 70
Albany 93 75 88 74 88 / 60 30 70 50 70
Valdosta 95 74 91 74 90 / 40 30 60 50 70
Cross City 94 75 93 74 90 / 20 30 40 30 40
Apalachicola 89 79 88 78 86 / 30 50 50 40 60
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Lamers
LONG TERM...Hollingsworth
AVIATION...Gould
MARINE...Lamers
FIRE WEATHER...Gould
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
420 AM CDT Tue Aug 13 2013
...Update to long term discussion...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 420 AM CDT TUE AUG 13 2013
Wednesday:
A 70 kt 250 hPa jet streak will traverse across western Kansas through
the day. At the sfc, an upslope flow regime is expected with weak 850
hPa warm air advection/theta-e advection across far western Kansas.
For spatiotemporal adjustments of precipitation probability percentage
points, have relied heavily on ECMWF output solutions. Wednesday is
shaping up to be another MCS day. Orographic convection is expected
to form across the high plains and then drift southeast across the region
during the late evening and overnight period. The precipitation numerical
values are still in the chance category. The NAM solution is still dry
for the most part - but this model has failed with the MCS events recently,
so I remain dubious of any described solution herein. The tail end of
both WRF cores also support more confidence in the ECMWF solution. Heavy
rain will be possible again as precipitable water values are forecast
around the 75th percentile for a Gaussian distribution. Otherwise, maximums
will be cool because of all the cloud cover and lack of low level downslope
flow. Followed the ECE for guidance, which shows values in the upper
70sF to around 80F. Minimums into Thursday morning will be in the lower
60sF.
Thursday:
Another MCS day is possible Thursday. Upper level flow is more NW during
this period as a result the amplification of 500 hPa ridging across
the spine of the Rockies. This flow may advect any MCS activity farther
east than compared to the previous day. Heavy rain could be a possibility
again, as pwats continue on the higher end of the distribution spectrum.
Maximum surface temperatures could be a few degrees (F) warmer, particularly
across the western zones, as the 850 hPa warm plume advects slightly
farther east. A gradient of upper 80sF to around 80F is expected from
the west to the east with lows in the 60sF.
Friday and beyond:
Stuck with the weighted model solution (allblend) for the rest of the
forecast period as uncertainty continues to increase. There could be
some late afternoon and evening convection across the eastern zones
in association with an enhanced region of 850 hPa frontogenesis that
the ECMWF solutions shows on Friday. A drier forecast is possible next
weekend as the aforementioned 500 hPa ridge amplifies and expands farther
east across the region with a net result of drier northerly flow aloft
and higher mid level geopotential heights. Temperatures will moderate
to near normal during this drier period. Another period of convection
is possible in about a week from now as a trof moves across the northern
prairies. Will continue to tread lightly.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 100 AM CDT TUE AUG 13 2013
Rain showers and isolated thunderstorms are expected to affect the
TAF locations (DDC, GCK, HYS) through 08-09z time frame.
Thereafter, a weakening trend in activity is expected. Prevailing
winds will be some variation of east through the night and into
the day Tuesday. Some temporary MVFR ceilings will be possible in
the 10-14z time frame...and perhaps some brief IFR. More showers
and thunderstorms are expected by afternoon as the southwest
Kansas region remains in a moist upslope low level pattern.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 60 60 30 40
GCK 77 60 78 62 / 50 50 30 40
EHA 83 60 81 62 / 60 60 40 40
LBL 82 61 80 63 / 70 70 30 40
HYS 76 60 78 60 / 40 30 30 40
P28 78 62 81 64 / 70 70 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
334 AM CDT Tue Aug 13 2013
...UPDATED SYNOPSIS AND SHORT TERM SECTION...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 218 PM CDT MON AUG 12 2013
As upper level ridging builds into the Intermountain West,
northwesterly upper level flow will prevail across the Plains into
Friday. Several ripples in the flow will bring slight chances for
showers and thunderstorms into western Kansas, mainly in the late
afternoons and evenings, into Friday Night. The upper level ridge
will slowly move east and weaken into the weekend with mainly dry
conditions and warming temperatures.
At the surface, broad high pressure will be found across the
Mississippi Valley into the Plains with a trough of low pressure
in the lee of the Rockies. Moist south to southeasterly surface
flow will prevail.
Overnight lows will gradually warm from the low 60s into the mid and
upper 60s by the weekend. Daytime highs will warm gradually from the
lower to mid 80s to around 85 to 90 by the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 100 AM CDT TUE AUG 13 2013
Rain showers and isolated thunderstorms are expected to affect the
TAF locations (DDC, GCK, HYS) through 08-09z time frame.
Thereafter, a weakening trend in activity is expected. Prevailing
winds will be some variation of east through the night and into
the day Tuesday. Some temporary MVFR ceilings will be possible in
the 10-14z time frame...and perhaps some brief IFR. More showers
and thunderstorms are expected by afternoon as the southwest
Kansas region remains in a moist upslope low level pattern.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 60 60 30 40
GCK 77 60 78 62 / 50 50 30 40
EHA 83 60 81 62 / 60 60 40 40
LBL 82 61 80 63 / 70 70 30 40
HYS 76 60 78 60 / 40 30 30 40
P28 78 62 81 64 / 70 70 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...KRUSE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
450 AM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AVN CONDITIONS THROUGH EAST KENTUCKY WILL REMAIN RATHER POOR DURING
THE REST OF THE NIGHT AS AREAS OF CONVECTION AND PATCHY FOG MOVE
THROUGH. HAVE LIMITED THE THUNDER AND VCTS CHANCES TO THE SOUTHERN
TAF SITES OF LOZ AND SME. ONCE THIS WAVE OF PCPN CLEARS LATE THIS
NIGHT WOULD ALSO EXPECT LOWER VIS FROM FOG...BUT PROBABLY NOT AS
DENSE AS WE SAW LAST NIGHT AT JKL. CONDITIONS WILL THEN IMPROVE
THROUGH THE DAY TUESDAY WITH JUST A SMALL CHANCE OF A SHOWER OR
THUNDERSTORM AND CIGS GENERALLY HOLDING IN THE VFR RANGE. WINDS
THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE...OUTSIDE OF ANY
THUNDERSTORM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
304 AM EDT Tue Aug 13 2013
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Aug 13 2013
A couple of fronts are headed our way today. The first is slower
moving and stretches roughly from Lake Erie right to our northern
row of counties. The second has a more noticeable dewpoint
difference and is located between Central Michigan and southern
Wisconsin. Expect the first front to bring a wind shift into the
Ohio River area in the next few hours, but the main drier air with
the second front will not get here until this afternoon.
With a continued moist airmass in place ahead of the first front, we
are seeing lines of showers/embedded thunder continue to develop
early this morning. Will continue to watch for training of heavier
cells, but that watch should end soon, as that second front brings a
great rest of the work week forecast.
Highs today will depend on who can see the most sunshine. Most
places will stay cloudy, keeping readings around 80. The northern
forecast area has the best chance to break out behind the front, but
north winds should temper the extra sunshine and keep readings in
the lower 80s. Tonight, a steady north wind will keep us from ideal
radiational cooling, but lows should fall into the 50s for most
everyone. Then Wednesday under full sunshine and a north/northeast
wind highs look to rise only to the mid/upper 70s. Dewpoints may
drop into the mid 40s across the north, very low for mid August!
.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Tue Aug 13 2013
Upper air pattern will undergo a transition during the extended
period from troughing centered over the eastern Great Lakes (which
has been the prevailing pattern almost all summer) to a more typical
mid-summer pattern in which flat zonal flow retreats well north of
the Canadian border. However, this latter zonal flow won`t really
become established until Monday or Tuesday of next week.
A very dry and unseasonably cool airmass will already be in place
across the Great Lakes and the Lower Ohio Valley by Wednesday
evening. By late Wednesday, high pressure of Canadian origin is
forecast to lie near Chicago, with a ridge axis extending southeast
toward West Virginia. Clear skies and light winds will allow for
almost perfect radiational cooling early Thursday, and some
remarkably cool (for mid-August) overnight lows are expected for
early Thursday morning. Some lows may dip below 50 across some of our
typically colder rural locations!
Expect mostly clear skies with very comfortable temperatures and
humidities through Friday morning as high pressure settles overhead.
Highs both Thursday and Friday will hover not too far from 80. Lows
early Friday morning will reach the mid 50s.
For Saturday and Sunday, surface high pressure will move over New
England, with ridging extending southwest over the Ohio
River. Winds will stay quite light through the weekend, mostly from
an easterly direction. A weak upper level disturbance will slide
south across Missouri late Friday and will establish a weak 500mb
trough across southern Illinois, which will basically stay in
place through Sunday.
Isolated to scattered showers and thunderstorms are expected to our
east over the southern Appalachians on Friday, this convection may
re-develop a bit farther west Saturday and Sunday as light easterly
winds at the surface combine with relatively cool 500mb highs to
bring moderate afternoon and evening instability each day. This
convection will not be as widespread nor produce the heavy downpours
that some locations experienced over this past weekend. They will
also tend to develop during the afternoon and diminish during the
evening hours. Overall expect partly cloudy skies this weekend with
relatively cool highs in the lower to mid 80s with overnight lows in
the 60s. Think that each afternoon, scattered thunderstorm coverage
will be greatest across our southeastern counties and most sparse
across southern Indiana.
&&
.AVIATION (06Z TAF Update)...
Issued at 1205 AM EDT Tue Aug 13 2013
Did an early round of updates to the TAFs as HRRR is indicating some
low cloud development in the wake of last night`s rains. KHNB is
coming in with these low clouds and think they will invade points
farther east as the night goes on. For now have gone with low-end
MVFR cigs, with worse conditions at KLEX by daybreak. Would not be
surprised to see some lower ceilings, but will introduce into the
TAFs for now and see how trends go the rest of the early morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........RJS
Long Term.........JSD
Aviation..........RJS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1215 AM CDT Tue Aug 13 2013
.UPDATE...
Updated aviation discussion only.
&&
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 1250 PM CDT MON AUG 12 2013
It looks like the blended model approach is too slow. It lingers
pops well after fropa into/thru Tuesday. We went with the HRRR and
Nam`s more meso type solutions, which had higher resolution and
initiated well. It has higher pops but departs them more quickly
with fropa and with the aforementioned finer resolution. It models
the initial environment well, so we at least are hoping for a nice
0-6 hr init with a transition toward the Nam in the overall pop
modeling thru Tuesday. Alot will be told here with how the
remainder of the pm/into the early evening goes. Should see fairly
active/high concentration convection to continue breaking out in
moist/unstable air ahead of incoming front/energy this pm-
evening...to sweep southward with time/with perhaps additional
development along main front as well as outflow boundaries thru
the overnight hours. Meso models take the front thru tonight and
start to usher in the drier air at the lower levels late tonight-
early tmrw, which should preclude pop mention. We`ll watch closely
and also see about collab as to whether to remove pop altogether or
leave lingering Tuesday pop. Certainly by Tue evening-overnight all
models are in agreement that the drier dew points are working thru
the column and we poise for the nice pleasant cooler/drier air to
take root from mid week on.
.LONG TERM /Wednesday through Monday/...
ISSUED AT 215 PM CDT MON AUG 12 2013
Unusually high amplitude flow pattern for the middle of August will
continue...with a large ridge in the west and a deep trough in the
Mississippi and Ohio Valley regions. The trough is forecast to
weaken late in the period /Monday/...which will result in some
semblance of a typical August pattern.
As far as the daily details...
An unseasonably strong /1023 mb/ surface high will progress slowly
east across the Great Lakes and upper Midwest Wednesday through
Thursday. This high will funnel a cool and dry air mass
southward...with 850 mb temps ranging from 10 to 12 for much of the
period. These 850 mb temps support highs only in the upper 70s with
full sun. Overnight lows will be in the lower to mid 50s. Generally
followed the cooler NAM mos for low temps...though the difference
between NAM and GFS mos is negligible in some places. It should be
noted that 850 mb temp anomalies Wed/Thu will be 2 to 3 standard
deviations below normal. The air mass will also be very dry. Model
soundings suggest nothing more than a few pancake cumulus clouds
each afternoon.
On Friday and Friday night...an inverted surface trough will
retrograde westward across the Tennessee Valley as a 500 mb
shortwave digs southeast into the Mississippi Valley. It will take a
while for the atmosphere to moisten up...so only the far southeast
counties /KHOP area/ nearest the surface trough are at risk of any
precip.
Saturday through Sunday...the upper trough will be nearly overhead.
Some guidance indicates the trough will close off into an upper low
over our region. At low levels...the inverted trough will take up
residence near or just south of our region. Dew point pooling along
the surface trough will bring dew points up through the 60s. Precip
water values are forecast to climb steadily to between 1.5 and 2
inches by Sunday /GFS model/. The models are considerably more
unstable than they were yesterday...so will add mention of thunder
for the weekend. Pops will be in the chance category in most areas
for Sunday. Most of the precip should be diurnally driven
convection.
On Monday...the upper trough is forecast to weaken and/or lift
northeast. The surface trough will dissipate...leaving only a
weakly cyclonic east to southeast flow. Precip chances will begin to
diminish from the west. Temps and humidity will gradually approach
climo.
&&
.AVIATION...
ISSUED AT 1215 AM CDT TUE AUG 13 2013
Winds across the area will be rather light and generally from the
west or sw shortly after midnight, until a cold front passes through
the area late in the night, which will turn winds to the nw.
There is a small chance of pcpn ahead of the front, but the
probability of occurrence was too low to include in TAFs. Winds just
off the sfc should be enough to preclude other than brief MVFR fog.
Instead, there may be some scattered low clouds associated with the
front. VFR conditions can be expected after sunrise, with a nwrly
breeze up to about 10 knots.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
Short term...DH
Long term...MY
Aviation...DB
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1209 AM EDT Tue Aug 13 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1135 PM EDT Mon Aug 12 2013
Main area of precipitation almost is out of the area, though heavy
rains continue in the Lake Cumberland region. Once that system
exits, we have some signs on radar of a few more bands that could
develop overnight, with the main front still to our north. Thus have
tweaked pops a little as well as matched up obs with ongoing
conditions. Also added in some patchy dense fog as we may get some
denser low clouds to drop in spots overnight. KHNB is reporting a
200 foot overcast this hour.
Issued at 1000 PM EDT Mon Aug 12 2013
Large cluster of convection continues to work eastward across the
state this evening. Torrential rainfall and quite a bit of
lightning have been the main weather threats with this activity.
Activity will continue to work eastward across the Lake Cumberland
region over the next few hours producing torrential rainfall and
lightning. Further norther, a break in the precipitation is
expected. However, some additional convection may accompany the
surface cold front as it continues to press southward through
northern Indiana and central Illinois. This will result in a
continued threat of a shower or storm into the overnight period,
with most locations seeing much drier weather toward dawn Tuesday.
Update issued at 602 PM EDT Mon Aug 12 2013
Currently watching two bands of convection work their way across the
Commonwealth this evening. The first batch is moving just south of
the Louisville metro area. This activity is becoming more outflow
dominated while the line surges eastward. Based on current radar
trajectories, this activity looks to pass just south of this
morning`s heavy rainfall axis which extended from near Spencer Co KY
to the Clark/Madison county border region. Additional convection is
developing over the northern Bluegrass where the atmosphere has had
time to recover this afternoon. Any of these storms will contain a
ton of lightning and torrential rainfall. The heavy rainfall and
flooding will be the major weather threats with this activity.
Second line of convection is organizing out across western
Kentucky...along a line from near OWB to just south of PAH. This
activity will head east and affect our south-central areas this
evening. Quite a bit of lightning and heavy rainfall will be the
threats here. However, hydro issues may be a bit more isolated as
rainfall has not been that much down there over the last 6-8 hours.
Nonetheless, any heavy rainfall will be capable of producing quick
rises on creeks, streams, and poor drainage areas.
.SHORT TERM (Now through Tuesday Night)...
Issued at 315 PM EDT Mon Aug 12 2013
The synoptic pattern this afternoon features zonal flow aloft,
which will transition to more of an eastern trough/western ridge
pattern through the period. A shortwave trough and associated
surface front will slide through the Ohio Valley late this afternoon
through the overnight hours, continuing to bring showers and
thunderstorms to the region.
Quite a complex forecast for the rest of today into tonight, as
several forcing mechanisms focus into a moist airmass that has
advected into the region. In the near term, a strong wave of
isentropic ascent will continue to lift northeast through the
northern Bluegrass. After that, there will likely be a brief lull
in the more widespread activity. However, with sunshine beginning
to peak out, renewed thunderstorm development will likely occur
which is already underway across southern Indiana and north-central
KY. Think this activity will remain scattered for the next few
hours, before the main forcing arrives this evening and increases
coverage. A strong shortwave trough, evident on water vapor imagery
across central MO, will quickly slide into the Ohio Valley. It is
just now beginning to interact with the best instability axis,
likely explaining the thunderstorm development recently occurring
across southeast MO. This activity will likely expand in coverage
through the next few hours as it heads across western IL and KY.
However, by the time it reaches the western CWA, it will likely be
in a weakening phase as we will not be quite as unstable.
Nonetheless, still think coverage will be about 60% as it enters the
west, possibly fading in coverage through the late evening into the
first part of the overnight hours as instability wanes. Heavy
rainfall will continue to be the main threat, although an isolated
severe storm will be possible given the better kinematics (effective
shear about 40 knots currently in southern IN/northern KY). This may
support some multicells or even a transient supercell structure
which may be capable of some strong wind gusts or perhaps even some
small hail.
Overnight, another wave looks as if it will push northeast along the
surface front, which may enhance the precipitation across southern
KY around midnight as a weak low-level jet develops. This
convection will push east by the late morning hours. Some
additional development is possible across mainly southern KY through
early Tuesday afternoon as another secondary front drops through the
region, but think any of this activity will remain rather isolated.
Canadian high pressure will build firmly into the region by Tuesday
night. After a muggy night tonight, cooler and drier air will push
in tomorrow, as highs fall into the low and mid 80s with much lower
humidity values. Have dropped temperatures a bit Tuesday night as
the Canadian high settles in. Lows will be quite chilly compared to
recent days as they bottom out in the mid 50s to lower 60s.
.LONG TERM (Wednesday through Monday)...
Issued at 315 AM EDT Mon Aug 12 2013
Surface High Pressure dominates the Ohio Valley for the majority of
the extended period. By Friday night, as the High starts to exit to
the east, southerly low level flow begins to return, and along with
it, a returning chance for precipitation - at least for the southern
counties along the Tennessee border. The GFS and Euro are in
agreement on this trend, but there are differences in the strength
of the 500 mb flow, with the GFS generating a closed low and
introducing showers as early as Friday evening, while the ECMWF
keeps the 500 mb flow an open wave, and brings the convection in on
Saturday. Both keep then spread the chance for showers and
thunderstorms across the CWA for Sunday and Monday.
Given that the main precip chances are in days 6 and 7, and that the
southerly surface flow appears more southeasterly in both models,
this looks to be a borderline shower/thunderstorm event, and
adjustments will no doubt made in intervening forecasts. For now,
the most certain statement that can be made is that the best weather
of the extended will be during the second half of this work week,
with clear skies, dry air and below normal temperatures ushering in
the start of the Kentucky State Fair.
High temperatures through the period will be in the upper 70s to low
80s. Lows Thursday and Friday mornings will be in the 50s across
the area, before moderating into the lower to mid 60s over the
weekend and Monday morning. Both the highs and lows are at or below
seasonal norms for mid August.
&&
.AVIATION (06Z TAF Update)...
Issued at 1205 AM EDT Tue Aug 13 2013
Did an early round of updates to the TAFs as HRRR is indicating some
low cloud development in the wake of last night`s rains. KHNB is
coming in with these low clouds and think they will invade points
farther east as the night goes on. For now have gone with low-end
MVFR cigs, with worse conditions at KLEX by daybreak. Would not be
surprised to see some lower ceilings, but will introduce into the
TAFs for now and see how trends go the rest of the early morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Updates........MJ/RJS
Short Term.....KJD
Long Term......JBS
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
410 AM EDT TUE AUG 13 2013
.SYNOPSIS...
AFTER A COLD FRONT BRINGS SHOWERS TODAY...COOL AND DRY CONDITIONS
CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
TWO MAIN AREAS OF RAIN CONTINUE TO PUSH TO THE EAST. NORTHERNMOST
TIER OF COUNTIES WILL HAVE SOME STRONG STORMS OVER THE NEXT FEW
HOURS...WHILE HEAVY RAIN WILL CONTINUE SOUTH OF THE MASON-DIXON
LINE. ALTHOUGH RAIN RATES ACROSS THE SOUTH HAVE DIMINISHED
CONSIDERABLY FROM WHAT THEY WERE AT MIDNIGHT...WILL CONTINUE THE
FLASH FLOOD WATCH UNTIL THE RAIN CLEARS THE REGION. IN BETWEEN THESE
TWO AREAS OF RAIN...ISOLATED SHOWERS/STORMS HAVE STARTED TO DEVELOP.
MAJORITY OF RAIN WILL MOVE OFF TO THE EAST BY MID MORNING.
HOWEVER...COLD FRONT WILL BRING SIGNIFICANTLY COLDER TEMPERATURES AT
850MB. SFC-850 TEMPERATURE DIFFERENCES WILL BE LARGE ENOUGH FOR SOME
LAKE EFFECT CLOUDS AND EVEN ISOLATED SHOWERS TO DEVELOP ALONG THE
COLD FRONT. WHILE MESOSCALE MODELS KEEP THE FORECAST DRY...HI-RES
MODELS INCLUDING THE HRRR SHOW THESE SHOWERS TO BEGIN BY EARLY
AFTERNOON. HAVE KEPT ISOLATED SHOWERS IN THE FORECAST THROUGH MOST
OF THE DAY TO ACCOUNT FOR THIS PRECIPITATION. WENT WITH LAMP
GUIDANCE FOR TEMPERATURES...WHICH YIELDS HIGHS ABOUT 10 DEGREES
BELOW NORMAL.
WHILE LAKE EFFECT CLOUD COVER WILL CONTINUE TONIGHT...THINK THAT
SHOWERS WILL NOT CONTINUE. BEHIND THE COLD FRONT...LOWS WILL BE
10-15 DEGREES COLDER THAN LAST NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
EXPECT QUIET WEATHER THROUGH THIS STRETCH WITH HIGH PRESSURE ACROSS
THE GREAT LAKES. HAVE LOWERED TEMPERATURES A COUPLE DEGREES
WEDNESDAY AND WEDNESDAY NIGHT. THIS NOW KEEPS LOCATIONS NORTH OF
PITTSBURGH IN THE 60S FOR HIGHS...AND DROPS MANY LOCATIONS TO THE
40S WEDNESDAY NIGHT. TEMPERATURES THURS/THURS NIGHT WILL BE ABOUT 5
DEGREES HIGHER THAN THE PREVIOUS DAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
WHILE HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER FRIDAY AND
FRIDAY NIGHT...TROPICAL MOISTURE WILL START TO MOVE IN FROM THE
SOUTH. THIS WILL RESULT IN INCREASING CHANCES FOR SHOWERS AND
STORMS. MODERATING TEMPERATURES SHOULD BE NEAR NORMAL BY SATURDAY.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
CONDITIONS OVERNIGHT SHOULD DETERIORATE WITH SHOWERS AND LOW CLOUDS
MOVING THROUGH. EXPECT MVFR. COULD SEE A BRF PD OF IFR AT PORTS N
AND W OF PIT. CLD FNT PASSES 10-14Z. MVFR CIGS SHOULD LINGER THROUGH
MOST OF THE MORNING AND INTO EARLY AFTERNOON. IT IS LIKELY THAT
EASTERN AND NORTHERN PORTS WILL HOLD ON TO MVFR CLOUDS THE LONGEST.
CONDITIONS WILL IMPROVE TO VFR CU/STRATOCU...FROM WEST TO EAST..
DURING THE AFTN. EXP A WSHFT FM SW TO NW AFT FROPA WITH SOME SPEEDS
12G20KT TUE AFTN.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
VFR CONDS EXPD THRU THE PD WITH BLDG HIGH PRES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH UNTIL 11 AM EDT THIS MORNING FOR MDZ001.
OH...NONE.
PA...NONE.
WV...FLASH FLOOD WATCH UNTIL 11 AM EDT THIS MORNING FOR WVZ012-
021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
448 AM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT TUE AUG 13 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
QUEBEC INTO NRN ONTARIO RESULTING IN CYCLONIC WNW FLOW THROUGH THE
NRN GREAT LAKES. LITTLE MORE THAN PATCHY MID CLOUDS WERE ASSOCIATED
WITH A SHORTWAVE TROUGH MOVING THROUGH WRN LAKE SUPERIOR WHILE MORE
EXTENSIVE CLOUDS AND A FEW SPRINKLES WERE OBSERVED WITH ANOTHER
SHRTWV JUST UPSTREAM...TO THE N OF LAKE SUPERIOR. AT THE SFC...HIGH
PRES OVER MANITOBA INTO NW MN WAS BUILDING INTO THE WRN LAKES WITH
NRLY FLOW PREVAILING ACROSS LAKE SUPERIOR INTO UPPER MICHIGAN.
TODAY...AS THE SHRTWV FROM N OF THE LAKE AND A POCKET OF LOWER 700 MB
TEMPS AROUND -6C...DROPS THROUGH THE CWA...MODELS SUGGEST THAT SOME
ISOLD SHOWERS WILL BE POSSIBLE FROM LATE THIS MORNING INTO THE EARLY
AFTERNOON...MAINLY THROUGH W CNTRL UPPER MI. IN ITS WAKE...SUBSIDENCE
AND DRYING WILL BUILD QUICKLY INTO THE AREA...ENDING ANY PCPN BY MID
TO LATE AFTERNOON.
TONIGHT...WITH CLEARING SKIES AND LIGHT WINDS AS THE HIGH BUILD INTO
THE REGION...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY
AIRMASS(PWAT TO AROUND 0.50 INCH OR 50 PCT OR NORMAL) WILL ALLOW
TEMPERATURES TO DROP TOWARD THE LOWER END OF GUIDANCE....INTO THE
MID TO UPPER 30S INLAND WEST. THE TYPICAL COLDER LOCATIONS FROM
CHAMPION AND AMASA TO WATERSMEET...KENTON AND WATERSMEET COULD SEE
SOME PATCHY FROST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 432 AM EDT TUE AUG 13 2013
THE VERY COOL MORNING TEMPS WILL QUICKLY RISE INTO THE UPPER 60S TO
MID 70S WEDNESDAY AS THE SFC HIGH OVERHEAD CONTINUES TO SLOWLY SINK
TO OUR SSE. A SLOW WARMING TREND WILL BEGIN WEDNESDAY NIGHT...WITH
THE SFC HIGH LINGERING ACROSS THE OHIO VALLEY AND NEW ENGLAND STATES
THROUGH AT LEAST THE START OF THE NEXT WORK WEEK.
THURSDAY WILL SEE A RETURN OF NEAR NORMAL HIGH TEMPS...IN THE
70S...AS 850MB TEMPS FINALLY RISE INTO THE DOUBLE DIGITS AND...STAY
THERE FOR THE REMAINDER OF THE FCST PERIOD.
THERE WILL BE ONLY FEW SYSTEMS OF NOTE OVER THE WEEK...WITH NW FLOW
ALOFT REMAINING IN PLACE THROUGH THE END OF THE WORK WEEK. THE MAIN
500MB LOW WILL BE SPINNING AROUND AND NEAR QUEBEC THROUGH THURSDAY
BEFORE EJECTING NE IN THE MAIN FLOW AROUND THE STRONGER POLAR LOW. A
SERIES OF SHORTWAVES WILL ATTEMPT TO ROUND THE HIGH AMPLITUDE RIDGE
OVER MUCH OF THE WESTERN STATES EARLY TO MID WEEK...
SEEING A SFC LOW TRACKING FROM S ALBERT AND SASKATCHEWAN ON FRIDAY
TO S CENTRAL CANADA OVER THE WEEKEND. THE 12/12Z ECMWF IS MUCH
QUICKER TO PUSH THE SFC LOW ACROSS HUDSON BAY OVER THE WEEKEND.
THERE ARE SIGNIFICANT ENOUGH TIMING DIFFERENCES BETWEEN THE
AVAILABLE GUIDANCE TO KEEP ONLY LIGHT CHANCE POPS IN THE FCST AS
WARM BUT MAINLY DRY AIR PUSHES IN ON SW WINDS AT THE SFC SATURDAY
THROUGH THE END OF THIS FCST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 123 AM EDT TUE AUG 13 2013
EXPECT VFR CONDITIONS AND LGT WINDS TNGT AS DRY HI PRES DOMINATES
UPR MI. MORE INSTABILITY CU/SC WL DVLP THIS MRNG AFTER SUNRISE WITH
ONSET OF DAYTIME HEATING AND THE APRCH OF ANOTHER DISTURBANCE...BUT
CONDITIONS ARE LIKELY TO BE VFR. BEST CHC FOR SOME MVFR CIGS LATER
THIS MRNG INTO THE AFTN WL BE AT SAW WITH MORE FVRBL UPSLOPE AND
GUSTY N WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT TUE AUG 13 2013
NRLY WINDS OF 15 TO 20 KNOTS OVER THE ERN PORTIONF OF LAKE SUPERIOR
WILL DIMINISH TONIGHT AS HIGH PRES BUILDS INTO THE REGION. AS THE
HIGH SINKS TO THE SOUTH WED INTO WED NIGHT WRLY WINDS OF 15 TO 20
KNOTS ARE ALSO EXPECTED OVER CNTRL AND ERN LAKE SUPERIOR.
OTHERWISE...WINDS AOB 15 KNOTS WILL PREVAIL INTO SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
419 AM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
&&
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1157 PM EDT MON AUG 12 2013
MVFR CIGS AT TIMES TONIGHT/TUESDAY MORNING. GUSTY NNW WINDS
TUESDAY.
AUTUMN-LIKE WX IN STORE...AS UNSEASONABLY COOL AIR ENTERS THE
REGION BEHIND A DEPARTING COLD FRONT. COOL AIR MOVING OVER THE
WARM GREAT LAKES WILL RESULT IN LAKE-INDUCED CLOUD COVER TONIGHT
INTO TUESDAY. MVFR CIGS EXPECTED AT ALL TAF SITES...IMPROVING TO
VFR DURING THE DAY ON TUESDAY. COULD BE A TOUCH OF DRIZZLE/-RA...
ESPECIALLY TVC/APN...BUT SMALL RISK IS NOT WORTH INCLUDING IN THE
TAFS AT THIS TIME.
NNW-ERLY BREEZE TONIGHT AND TUESDAY...RATHER GUSTY BY MIDDAY
TUESDAY.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...JZ
MARINE...MB
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1201 AM MDT Tue Aug 13 2013
.UPDATE...
Increased POPS for the rest of the night for the northeast zones as
showers and thunderstorms continue to develop along multiple outflow
boundaries. Expect coverage of precipitation to begin decreasing in
a few hours as the shortwave and associated lift move east. Langlieb
&&
.AVIATION...
UPDATED 0505Z.
Scattered thunderstorms continue across central and north central MT
from northeast of KGTF to east of KHVR, producing good amount of
lightning and moderate to locally heavy rainfall. Storms have also
been putting out gusty outflow winds of 25-35 kts. Storm cells are
expected to gradually dissipate between now and 08Z with ceilings
increasing to greater than 10000 ft at that time. Clear skies to
scattered clouds and light winds expected overnight. Tuesday will
be near-repeat of Monday`s weather as scattered thunderstorms
develop again during the afternoon/evening.
Waranauskas
&&
.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Aug 12 2013/
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Suk
LONG TERM...mpj
AVIATION...WARANAUSKAS
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1105 PM MDT Mon Aug 12 2013
AVIATION SECTION UPDATED
.UPDATE...
Increased pops and QPF across much of the eastern part of the zone
as showers and thunderstorms continue to move across central
Montana. The active weather pattern will continue through the
evening hours with some of the shower activity lasting well past
midnight. No significant changes to other parts of the forecast as
most of the impact tonight will be associated with the severe
thunderstorms. Suk
&&
.AVIATION...
UPDATED 0505Z.
Scattered thunderstorms continue across central and north central MT
from northeast of KGTF to east of KHVR, producing good amount of
lightning and moderate to locally heavy rainfall. Storms have also
been putting out gusty outflow winds of 25-35 kts. Storm cells are
expected to gradually dissipate between now and 08Z with ceilings
increasing to greater than 10000 ft at that time. Clear skies to
scattered clouds and light winds expected overnight. Tuesday will
be near-repeat of Monday`s weather as scattered thunderstorms
develop again during the afternoon/evening.
Waranauskas
&&
.PREV DISCUSSION...
/ISSUED 530 PM MDT Mon Aug 12 2013/
Tonight through Wednesday...Overall pattern has changed little
from Sunday. The airmass is a bit more unstable this afternoon
with CAPE values of 1000 to 2000 J/kg across the northern portion
of the county warning area. Shear values, though not overly
impressive, have also increased from earlier this morning and with
high precipitable water, the result is thunderstorm development.
The weak steering flow aloft will make very slow movers with these
storms and heavy rain will be the primary threat (although some
hail cannot be ruled out). HRRR and RUC analysis continue to
develop thunderstorms over Great Falls as late as 04 to 05z. Drier
conditions over southwest Montana will translate to isolated
thunderstorms this evening. Enough instability will exist Tuesday
afternoon to allow isolated to scattered thunderstorms to develop
again though areal coverage should be less. Rising H5 heights
Wednesday will herald the beginning of a drier and warmer regime.
Temperatures will be near or slightly above seasonal averages.
Emanuel
Wednesday Night through Monday...Medium range forecast remains
relatively unchanged tonight. Models are in good agreement from
mid-week until early in the weekend and indicate that an upper level
ridge will be over the Rocky Mountains for a very warm and generally
dry forecast period. Model consensus for the weekend through early
next week remains elusive. Models agree that the ridge will be
pushed eastward on Saturday as a broad upper level trough moves
inland along the west coast. Beyond Saturday, models set up a
roughly zonal flow aloft but bring multiple and frequent short waves
over the region. Unfortunately, the wave phase and speed differ
markedly between the models and significant disagreement with regard
to pops/clouds/weather timing arises. Am sticking with a solution
that trends temperatures slightly cooler and increases pops toward
climatology for the weekend through Monday. mpj
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 55 84 55 86 / 40 30 30 20
CTB 52 82 52 85 / 40 30 20 10
HLN 57 86 57 89 / 30 30 40 20
BZN 50 85 49 86 / 30 30 30 20
WEY 39 78 37 78 / 10 20 20 10
DLN 49 83 49 84 / 20 20 20 20
HVR 57 82 56 84 / 40 20 30 20
LWT 54 81 53 81 / 40 40 30 30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Suk
LONG TERM...mpj
AVIATION...WARANAUSKAS
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1241 AM CDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 1241 AM CDT TUE AUG 13 2013
LOW TEMPS WERE RAISED 2-3F WITH THIS ESTF UPDATE BASED ON CURRENT
AND EXPECTED CLOUD COVER. ALSO REMOVED POPS FOR THE NEXT 3 HRS. WE
ARE NOTING SHWRS WITH OCCASIONAL THUNDER DEVELOPING OVER SRN SD
DOWN INTO THE SANDHILLS. PER THE PREVIOUS SHIFTS EXPECTATION...
THESE SHWRS SHOULD ARRIVE INTO S-CNTRL NEB BEFORE DAWN AND COULD
COMPLICATE TOMORROW`S FCST. CLOUDS WERE ALSO INCREASED THRU
DAYBREAK.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
THE MAIN ISSUES DURING THE NEXT 24 HOURS INCLUDE FICKLE
THUNDERSTORM CHANCES...ALONG WITH WHETHER OR NOT FOG TONIGHT MIGHT
END UP BEING IMPACTFUL IN SOME SPOTS.
20Z OBJECTIVE SURFACE ANALYSIS SHOWS A WEAK COLD FRONT STRETCHED
ACROSS KS FROM SOUTHWEST-NORTHEAST...WHILE TO THE NORTH OF THIS
BOUNDARY...THE MAJORITY OF THE CWA IS EXPERIENCING LIGHT BREEZES
RANGING FROM NEAR-CALM TO NO MORE THAN 5-10 MPH FROM THE EAST-
NORTHEAST UNDER THE INFLUENCE OF BROAD HIGH PRESSURE EXTENDING
WELL SOUTHWARD FROM CANADA. ALOFT...WATER VAPOR IMAGERY AND SHORT
TERM MODEL DATA SHOWS GENERALLY WEST-NORTHWEST FLOW ALOFT OVER THE
CENTRAL PLAINS...MORE WESTERLY UP AROUND 300 MILLIBARS..AND MORE
NORTHERLY FARTHER DOWN IN THE MID LEVELS 500/700 MILLIBARS. THIS
FLOW REGIME REMAINS ESTABLISHED BETWEEN A LARGE SCALE TROUGH OVER
THE GREAT LAKES/SOUTHEAST CANADA AREA...AND A RIDGE EXTENDING
NORTH-NORTHWEST INTO THE ROCKIES OUT OF THE TX/NORTHERN MEXICO
AREA. IN TERMS OF THE REGIONAL SCALE...THE MAIN LOW AMPLITUDE
DISTURBANCE OF INTEREST HAS PASSED ONTO THE EAST INTO
MO...ALTHOUGH SMALL RIBBONS OF CHANNELED VORTICITY ARE EVIDENT
EXTENDING BACK WEST-NORTHWEST ACROSS THE SOUTHERN CWA TOWARD THE
WY/NE/CO BORDER AREA PER LATEST OBJECTIVE MESO-ANALYSIS.
DESPITE WHAT VARIOUS MODELS WERE EARLIER-SHOWING...THE CWA HAS
REMAINED DRY ALL DAY IN THE WAKE OF THE EXTENSIVE CONVECTION
SUNDAY EVENING/EARLY THIS MORNING. VISIBLE SATELLITE REVEALS ONLY
A SCATTERED TO LOCALLY BROKEN FAIR WEATHER CUMULUS FIELD MAINLY IN
THE FAR NORTHERN/EASTERN/SOUTHERN COUNTIES...AND HIGH TEMPERATURES
ARE ON TRACK TO TOP OUT 82-85 NEARLY ALL AREAS.
FOR LATE THIS AFTERNOON INTO THIS EVENING...MODELS CONTINUE TO
STRUGGLE WITH THEIR INDIVIDUAL QPF FIELDS...AS SOME APPEAR TO
THINK THAT CONVECTION WILL BREACH A WEAK CAP LOCALLY. LEANING
TOWARD THE HIGHER-RES SOLUTIONS OF THE HRRR AND 4KM WRF
NMM/ARW...IT APPEARS RATHER UNLIKELY THAT ANYTHING WILL POP IN THE
NEXT 3-6 HOURS ESPECIALLY ACROSS THE CENTRAL/EASTERN CWA DUE TO
LACK OF FORCING AND LACK OF LOW-LEVEL CONVERGENCE...AS THE WEAK
CAP SHOULD HOLD DESPITE THE PRESENCE OF 1000-1500 J/KG 0-1KM MIXED
LAYER CAPE PER LATEST RUC ANALYSIS. AS A RESULT...THROUGH MIDNIGHT
HAVE CONFINED SLIGHT POPS TO MAINLY THE WESTERN 1/4 TO 1/3 OF THE
CWA...MAINLY TO ACCOUNT FOR THE SMALL POSSIBILITY THAT STORMS
CURRENTLY DEVELOPING IN WESTERN NEB...AND MAYBE EVENTUALLY IN
NORTHWEST KS AS WELL...MIGHT SLIP EASTWARD INTO THE CWA. GIVEN THE
CONTINUED WEAK DEEP LAYER SHEAR REGIME ONLY AROUND 20KT...AND
INSTABILITY FADING WITH TIME TONIGHT...THINK THE PROBABILITY OF
STRONG THUNDERSTORMS...LET ALONE SEVERE...IS QUITE LOW. AFTER
MIDNIGHT...UNCERTAINTY CONTINUES TO GROW...BUT WITH BOTH THE
LATEST HRRR AND 18Z NAM ADVERTISING SOME CONVECTION FLARING UP
MAINLY JUST NORTHWEST OF THE CWA LIKELY IN RESPONSE TO SOME SUBTLE
MID LEVEL THETA-E ADVECTION...AND OTHER MODELS SHOWING CONVECTION
LURKING IN OR NEAR KS ZONES...WENT AHEAD AND EXPANDED 20-30 POPS
TO INCLUDE ALL BUT A HANDFUL OF SOUTHEASTERN COUNTIES JUST IN
CASE. THE OTHER POTENTIAL ISSUE TONIGHT IS FOG. WHILE MET/MAV
GUIDANCE IS SUGGESTING ONLY SOME LIGHT FOG...THE 15Z SREF SUGGESTS
PERHAPS AN ENHANCED RISK OF VISIBILITY RESTRICTIONS BELOW 1 MILE
ESPECIALLY ACROSS THE SOUTHWEST 1/3 OF THE CWA LATE TONIGHT.
CERTAINLY THE VERY LIGHT EASTERLY FLOW REGIME AND RECENT RAINFALL
COULD HELP THE CAUSE OF FOG FORMATION...BUT GIVEN THAT FOG DID NOT
BECOME TOO MUCH OF AN ISSUE LAST NIGHT IN THE WAKE OF DEPARTING
CONVECTION WITH A SIMILAR WIND REGIME...DECIDED TO ONLY INTRODUCE
A PATCHY FOG MENTION CWA-WIDE FOR NOW LATE TONIGHT...AND DEFER TO
NEXT FEW SHIFTS TO MONITOR THE SITUATION AND RAMP UP FOG POTENTIAL
IF NECESSARY.
TURNING TO THE TUESDAY DAYTIME HOURS...THE QUESTIONS JUST CONTINUE
TO ARISE. TAKING VARIOUS MODEL QPF FIELDS AT FACE VALUE...THERE
COULD BE QUITE A BIT OF ONGOING CONVECTION DURING THE
DAY...ESPECIALLY ACROSS THE WESTERN HALF OF THE CWA...POSSIBLY AS
A CONTINUATION OF OVERNIGHT ACTIVITY MOVING IN...OR LOCAL
DEVELOPMENT RAMPING UP WITH DAYTIME HEATING...AS THE THERMODYNAMIC
STRUCTURE OF THE ATMOSPHERE SHOULD REMAIN SIMILAR TO TODAY WITH
WEAK CAPPING IN THE PRESENCE OF ROUGHLY 1000 J/KG OF CAPE. THE
MILLION DOLLAR QUESTION IS WHETHER NOT FORCING WILL BE STRONG
ENOUGH TO REALIZE THE POTENTIALLY WIDESPREAD CONVECTION ADVERTISED
BY SOME MODELS...OR WHETHER MODELS ARE OVER-DOING QPF AS SEVERAL
DID FOR TODAY. THERE SHOULD AT LEAST BE A FEW SUBTLE SHORTWAVE
TROUGHS PASSING THROUGH THE REGION PER MODEL VORTICITY
FIELDS...PRIMARILY PASSING ACROSS THE SOUTHWEST 1/2 OF THE CWA AND
POINT SOUTH. FOR NOW...DECIDED TO MAKE LITTLE CHANGE TO PREVIOUS
FORECAST WHICH ALREADY HAD POPS LOW AT NO MORE THAN 20-30
PERCENT...WITH THESE CHANCES COVERING MOST OF THE CWA IN THE
MORNING...AND THE ENTIRE AREA IN THE AFTERNOON. IF FORCING IS IN
FACT ENOUGH TO GENERATE WIDESPREAD CONVECTION...THEN NEXT SHIFT
MAY HAVE TO RAISE POPS NOTICEABLY ESPECIALLY IN WESTERN
AREAS...BUT AFTER SEEING HOW TODAY ENDED UP BONE-DRY THROUGH LATE
AFTERNOON...THINK IT WOULD BE UNWISE TO GET CARRIED AWAY WITH RAIN
CHANCES EVEN 12-24 HOURS OUT. AGAIN...NOT EXPECTING ANY SEVERE
STORMS...BUT A LOCALIZED STRONG STORM PROBABLY NOT OUT OF THE
QUESTION. OBVIOUSLY HIGH TEMPERATURES WILL BE HIGHLY DEPENDENT ON
THE COVERAGE...OR LACK THEREOF...OF DAYTIME CONVECTION...SO THERE
IS SOME UNCERTAINTY HERE TOO. GIVEN A SIMILAR LOW-LEVEL TEMP
REGIME...BLENDED THE COOLER PREVIOUS FORECAST FOR TOMORROW WITH
READINGS SIMILAR TO THOSE OBSERVED TODAY...WHICH RESULTS IN A
SLIGHT INCREASE TO PREVIOUS HIGHS AND NOW CALLING FOR 79-82 MOST
AREAS. BREEZES DURING THE DAY SHOULD AVERAGE ONLY 5-10 MPH FROM
THE EAST ASSUMING CONVECTIVE OUTFLOW DOESN/T GET TOO INVOLVED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM CDT MON AUG 12 2013
HE COOLER THAN NORMAL TREND WILL LIKELY CONTINUE THROUGH AT LEAST
SATURDAY...WITH PERHAPS A RETURN OF NEAR NORMAL HIGHS BY SUNDAY AND
MONDAY. WEAK SHORT WAVES WILL TRACK ACROSS OUR FORECAST AREA WITHIN
THE PERSISTENT UPPER LEVEL NORTHWESTERLY FLOW REGIME.
CONSEQUENTLY...ISOLATED TO SCATTERED THUNDERSTORMS WILL REMAIN
POSSIBLE ACROSS AT LEAST PORTIONS OF OUR FORECAST AREA OFF AND ON
AGAIN THROUGH MUCH OF THE PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY...A DECENT 500 MB VORT MAX/SHORT
WAVE WILL TRACK SOUTHEAST ACROSS THE HIGH PLAINS BRINGING A CHANCE
OF THUNDERSTORMS PRIMARILY TO AREAS WEST OF OUR FORECAST AREA.
HOWEVER...THERE IS GENERALLY A SLIGHT CHANCE THAT A FEW OF THESE
THUNDERSTORMS COULD TRACK INTO OUR WESTERN ZONES PRIMARILY WEST OF
HWY 281. INSTABILITY AND SHEAR ARE BOTH WEAK AND THUS ANY
THUNDERSTORMS THAT WORK INTO OUR AREA WILL LIKELY BE NON SEVERE.
TEMPERATURES WILL BE COOL FOR THIS TIME OF YEAR WITH THE UPPER LEVEL
JET STREAM TO OUR SOUTH.
WEDNESDAY NIGHT THROUGH FRIDAY...THIS SHOULD BE OUR BEST CHANCE AT
MORE WIDESPREAD THUNDERSTORM POTENTIAL ACROSS THE FORECAST AREA AS
A TRAIN OF SUCCESSIVE SHORT WAVE TROUGHS WORK THEIR WAY ACROSS THE
CENTRAL PLAINS. UPPER LEVEL SHEAR AND INSTABILITY WILL ALSO BE ON
THE INCREASE ESPECIALLY THURSDAY AFTERNOON THROUGH FRIDAY...WHICH
MAY RESULT IN A FEW STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. AT
THIS POINT...IT DOES NOT APPEAR TO BE A WIDESPREAD SEVERE
EVENT...BUT CAN NOT RULE OUT THE POSSIBILITY OF ISOLATED SEVERE
STORMS. TEMPERATURES WILL REMAIN RELATIVELY COOL...UPPER 70S TO
AROUND 80 DUE TO CLOUDS...POTENTIAL PRECIPITATION...AND MEAN MID
AND UPPER LEVEL JET POSITION.
SATURDAY AND SUNDAY...A BIT OF AN UPPER RIDGE IS PREDICTED TO WORK
INTO OUR FORECAST AREA THAT IF IT VERIFIES WOULD RESULT IN DRY
CONDITIONS THIS WEEKEND AND THEN WARMING TEMPERATURES TO NEAR NORMAL
BY SUNDAY.
SUNDAY NIGHT AND MONDAY...THE NEXT UPPER SHORT WAVE IS PROJECTED BY
BOTH THE 12Z GFS AND 12Z ECMWF TO MOVE INTO THE CENTRAL PLAINS. THIS
WILL RESULT IN AT LEAST SOME CHANCE OF THUNDERSTORMS...PARTICULARLY
ACROSS OUR WEST...ALTHOUGH THESE CHANCES MAY EVENTUALLY NEED TO BE
EXPANDED/RAISED SHOULD CURRENT FAVORABLE MODEL TRENDS CONTINUE.
ALLBLEND GIVES US NEAR NORMAL TEMPERATURES...AND LIKELIHOOD IS THAT
WE WILL LIKELY BE NO WARMER THAN NORMAL...AND WOULD NOT BE SURPRISED
IF MONDAY HIGHS GET LOWERED SOME WITH FUTURE FORECAST UPDATES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1241 AM CDT TUE AUG 13 2013
REST OF TNGT: VFR THRU 10Z WITH OCCASIONAL CIGS AROUND 5K FT. THEN
SOME MVFR FOG IS POSSIBLE 11Z-12Z. LIGHT E WINDS.
TUE: VFR WITH SCT SHWRS AND POSSIBLE THUNDER. TIMING OF ANY PCPN
IS UNCERTAIN GIVEN ITS SCT NATURE. SO IT`S BEEN HANDLED WITH VCSH
FOR NOW. WATCH FOR POSSIBLE AMENDMENTS TO UPGRADE TO TSRA. ESE
WINDS LESS THAN 10 KTS.
TUE EVNG: VFR WITH SOME MISC DEBRIS CLOUDS AROUND 8K AND 25K FT.
WINDS WILL BECOME LIGHT AND VARIABLE.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: MEDIUM
WIND CONFIDENCE: HIGH
WX CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
150 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TONIGHT AND PASS THROUGH THE
REGION ON TUESDAY...ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. FAIR
AND COOLER WEATHER WILL FOLLOW THE FRONT...WITH SLOWLY MODERATING
TEMPERATURES INTO LATE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
900 PM EDT UPDATE...
ISOLATED LIGHT RAIN SHOWERS HAS DEVELOPED ACROSS THE REGION TONIGHT
WHERE WAA AND THETA-E ADVECTION IS TAKING PLACE AHEAD OF AN
APPROACHING UPPR LOW. VORT MAXES ARE BEING EJECTED FROM THE BASE OF
THE TROUGH AND ARE MOVING WITHIN THE CYCLONIC FLOW OVER THE
REGION...THUS EXPECT THESE SHOWERS TO CONTINUE AHEAD OF THE FROPA.
AS THE WAA CONTINUES OVERNIGHT...EXPECT SHOWERS TO BECOME MORE
SCATTERED LIKE IN NATURE.
SKY COVERAGE HAS INCREASED OVER THE REGION THUS DO NOT BELIEVE
THAT TEMPS WILL FALL MUCH FURTHER TONIGHT AS DENSE COVERAGE WILL
INHIBIT HEAT LOSS.
PREVIOUS FORECAST HOLDS GOOD AS FROPA IS EXPECTED TO MOVE THROUGH
TUESDAY MORNING.
PREVIOUS FORECAST...
BATCH OF -SHRA OVER SW NY HAVING A TUFF TIME MAKING EWD PROGRESS
INTO CNTRL NY...BUT A FEW -SHRA WILL PRBLY WORK INTO THE SRN TIER
AND NE PA LATER THIS AFTN AND EVNG. BETTER CHCS FOR SHRA/TSRA WILL
COME LATER TNGT THROUGH MIDDAY TUESDAY AS A COLD FRONT PASSES THE
RGN. NAM HAS CDFNT JUST ENTERING THE FINGER LAKES AND WRN SRN TIER
BY 12Z...MOVG SEWD AND PASSING AVP ARND 19Z...AND SHOWS A WEAK
WAVE OF LOW PRES TRACKING ENEWD ALONG THE FNT WITH A PSN NEAR BGM
BY 15Z. GFS IS A FEW HRS SLOWER THAN THE NAM.
NAM SHOWS BEST AXIS OF QPF JUST N OF A LOW TRACKING ENEWD ALONG THE
FNT...FROM THE CNTRL SRN TIER AND SRN FINGER LAKES INTO THE WRN
MOHAWK VLY...WITH MAX QPF OF 1 TO 1.5 INCHES. THIS LOW IS NOT
EVIDENT IN THE OTHER MDLS. HOWEVER...BOTH THE NAM/GFS SHOW PRE-
FNTL PRECIPITABLE WATER RISING TO NEAR 1.5 INCHES. SUGGESTIONS OF
STRENGTHENING UPR LVL DVRGNC IN RR QUAD OF AN UPR LVL JET TMRW. SO
LOCALLY HEAVY RAINS ARE A POSSIBILITY AS THIS SYSTEM WORKS
THROUGH. GREATEST CAPES ON TUE WILL BE OVER NE PA BY MIDDAY PRBLY
MAXING OUT IN THE 500-750 J/KG RNG. SPC HAS SLGT RISK AREAS S AND
E OF THE FCST AREA AND LOOKS GOOD. HOWEVER...WE`LL HAVE TO MONITOR
FOR PSBLTY OF A FEW STRONG STORMS THERE ARND MIDDAY. CONDITIONS
SHOULD BE IMPROVING ACROSS MUCH OF CNTRL NY IN THE AFTN...SPCLY
OVER THE FINGER LAKES AND CNTRL SRN TIER.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
POTENT UPR LVL TROF...WHICH REMAINS WELL WEST OF THE INITIAL
CDFNT...MOVS INTO WRN/CNTRL NY TMRW EVNG...ACCOMPANIED BY A WEAK
2NDRY SFC TROF WHICH IS FCST TO BE OVER LOWER LAKE ONTARIO BY 00Z
WED. THESE FEATURES...IN COMBINATION WITH LAKE INFLUENCES
SUGGESTS SCT -SHRA ACRS PORTIONS OF CNTRL NY TMRW EVNG IN NNWLY
FLOW...ACTIVITY WHICH SHOULD DSPT LATE AT NGT AS MORE STABLE AND
DRIER AIR WORKS IN. NAM/GFS LOW LVL RH FIELDS AND FCST SKEW-T`S
SUGGESTS PTNL FOR LOW CLDS/STRATUS IN THIS COOLER NNW FLOW LATER TUE NGT
INTO EARLY WED MRNG. PROFILES ALSO SHOW THE LIKELIHOOD OF
DIURNALLY ENHANCED SCT-BKN CU OR STRATO-CU BOTH WED AND THU AFTN.
TEMPS WILL BE ON THE COOL SIDE WED...MODERATING TO MORE SEASONABLE
LVLS BY THU AFTN. CAN XPCT BREEZY CONDITIONS ON WED AS THE GTLAKES
HIGH BUILDS IN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
1 PM MON UPDATE... ON THE LARGE-SCALE...THE TWO MAIN FIXTURES THIS
PD WILL BE A STRENGTHENING WRN ATLANTIC UPR RIDGE...AND A WRN
CONUS UPR RIDGE AXIS. IN BETWEEN THE TWO...A WEAKNESS IN THE HGT
FIELDS LOOKS TO EXIST...WITH A FLAT MEAN TROUGH AXIS IN PLACE FROM
THE TN VLY SWD TO THE GULF STATES. THE PRIMARY INFLUENCING SYSTEM FOR
NY/PA DURG THIS TIME FRAME SHOULD BE THE WRN ATLANTIC UPR
RIDGE...WITH A STG "BERMUDA HIGH" TYPE SFC ANTICYCLONE...EXTENDING
FROM THE WRN ATLANTIC...BACK OVER THE ERN STATES.
THIS SYNOPTIC PATN SEEMS FAVORABLE FOR A PROLONGED STRETCH OF DRY
WX ACRS OUR FA...ALG WITH SLOWLY WARMING TEMPS OVER TIME. THE
LATEST GFS/EC/WPC PROGS AGREE THAT THIS WILL INDEED BE THE CASE.
FROM THIS EARLY VANTAGE PT...IT APPEARS THAT THE FIRST REAL CHC
FOR ANY PCPN WON`T BE TIL SOMETIME EARLY NEXT WEEK (MON OR PERHAPS
BEYOND)...WHEN SOME GULF MOISTURE ATTEMPTS TO PUSH NWD. EVEN AT
THAT...WE`RE ONLY ADVERTISING SCHC-CHC POPS ATTM FROM LATE SUN NGT
INTO NEXT MON.
TEMPS WILL BE FAIRLY SEASONABLE MUCH OF THE PD...WITH HIGHS
STARTING OFF IN THE 70S THU...GRADUALLY MODERATING INTO THE LWR-
MIDDLE 80S BY LTR IN THE WEEKEND/NEXT WEEK.
PREV DISC... 230 AM MON UPDATE... NO CHANGE FROM PREVIOUS FCST AS
STRONG HIGH PRESSURE WILL ENSURE COOL AND FAIR WX THROUGH THE BULK
OF THE PERIOD. SOME HINTS AT INCREASING MOISTURE TOWARDS NEXT
WEEKEND WITH SHWRS/STORMS POSSIBLE BY SUN NGT/MON AS UPPER LOW
BEGINS LIFTING NORTH FROM THE OHIO/TENN VLYS AND SFC HIGH PRESSURE
BREAKS DOWN OVER NEW ENGLAND. WITH MAX JET ENERGY EXPECTED TO
REMAIN SOUTH OF THE REGION...BETTER CHANCES FOR SHWRS/STORMS WILL
EXIST FROM THE CENTRAL MID-ATLANTIC SOUTH. TEMPS SHOULD BEGIN
MODERATING TOWARDS THE END OF THE WEEK WITH UPPER 70S TO NEAR 80
POSSIBLE BY SATURDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
06Z UPDATE...
AN AREA OF RAIN WITH EMBEDDED THUNDER CONTINUES TO MARCH ACROSS
WESTERN NY AHEAD OF A COLD FRONT. EXPECT RAIN TO ARRIVE AT ALL
TERMINALS BETWEEN 07Z AND 11Z. BASED ON OBS TO OUR WEST AND A
MOISTURE LADEN ATMOSPHERE...IFR VSBYS ARE LIKELY FOR A 3 TO 4 HOUR
PERIOD THIS MORNING DUE TO MODERATE/HEAVY RAIN. INCLUDED A TEMPO
GROUP TO COVER THIS ROUGHLY IN THE 08Z TO 14Z TIME FRAME. FOR NOW
I LEFT OUT ANY MENTION OF THUNDER IN THE TAFS WITH WEAKER LAPSE
RATES ACROSS OUR AREA. WITH THE 09Z UPDATE I MAY HAVE TO ADD IN
THUNDER CHANCES IF LIGHTNING STRIKES REMAIN IMPRESSIVE.
ONCE THE INITIAL AREA OF RAIN MOVES TO THE EAST...NOTHING
WIDESPREAD ENOUGH IS EXPECTED TO OCCUR TO INCLUDE IN THE TAFS.
MVFR CIGS ARE POSSIBLE FOR A FEW HOURS BEFORE VFR RETURNS LATER
THIS AFTERNOON.
SOUTHWEST WINDS WILL SHIFT AROUND TO THE NW AFTER FRONT PASSES
THIS AFTERNOON. GENERALLY WINDS WILL BE 5 TO 10 KTS BUT WE MAY SEE
A FEW GUSTS ABOVE 10 KTS BEHIND THE FRONT THIS AFTERNOON.
OUTLOOK...
TUE NGT...A PD OF MVFR CIGS PSBL...SPCLY ACRS CNY.
WED THRU SAT...MAINLY VFR. THE ONLY EXCEPTION WILL BE PSBL EARLY
AM VLY FOG AT KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KAH
SHORT TERM...
LONG TERM...CMG/MLJ
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
323 AM EDT TUE AUG 13 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN ACROSS THE REGION TODAY BEHIND A
DEPARTING COLD FRONT. FAIR WEATHER WITH BELOW NORMAL TEMPERATURES
AND PARTLY CLOUDY SKIES ARE EXPECTED FOR THE REMAINDER OF THE WORK
WEEK. THE HIGH WILL WEAKEN OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE FRONTAL PRECIPITATION ACROSS THE OHIO RIVER WILL GRADUALLY
SHIFT SOUTHEASTWARD THIS MORNING. COLD FRONT CURRENTLY LOCATED
ALONG AN INDIANAPOLIS TO LIMA LINE WILL CONTINUE ITS PROGRESSION
SOUTHEASTWARD THIS MORNING. BY THE LATE MORNING THIS FRONT IS
EXPECTED TO HAVE CLEARED ALL OF OUR ZONES. ANY LINGERING
PRECIPITATION ACROSS THE SOUTHEAST WILL END THIS MORNING AS THE
FRONT PASSES.
NORTHWESTERLY FLOW WILL INCREASE DURING THE DAY AS HIGH PRESSURE
BUILDS SOUTHEASTWARD OUT OF CENTRAL CANADA. EXPECT WINDS AROUND
15 MPH GUSTING UP TO 25 MPH AT TIMES DURING THE AFTERNOON. THERE
IS NOT MUCH MOISTURE TO SPEAK OF BEHIND THE FRONT EXCEPT FOR THAT
WHICH WILL ORIGINATE FROM EVAPORATION OFF THE GREAT LAKES.
THEREFORE AM EXPECTING MOSTLY SUNNY SKIES THIS AFTERNOON. COLD
ADVECTION TODAY WILL KEEP TEMPERATURES FROM RISING ABOVE THE MIDDLE
70S ACROSS THE NORTH TO NEAR 80 ACROSS THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE OUR WEATHER THROUGH THURSDAY NIGHT.
EXPECT MOSTLY CLEAR SKIES WITH LIGHT WINDS UNDER THIS DRY AIRMASS.
HIGH TEMPERATURES WILL BE IN THE LOW TO MIDDLE 70S ON WEDNESDAY AND
THE MIDDLE TO UPPER 70S ON THURSDAY. NIGHTTIME LOWS WILL BE IN THE
LOW 50S TONIGHT AND WEDNESDAY NIGHT...WITH A FEW LOCATIONS
DROPPING ITO THE UPPER 40S WEDNESDAY NIGHT. OVERNIGHT LOWS
THURSDAY NIGHT WILL BE A TAD WARMER THAN WEDNESDAY NIGHT. HOWEVER...
THESE VALUES WILL STILL BE A SEASONABLY COOL MIDDLE TO UPPER 50S
FOR THE MOST PART.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
PERIOD BEGINS WITH A HIGH PRESSURE AREA STRETCHING ACROSS THE
OHIO VALLEY. THE HIGH WILL REMAIN ANCHORED OVER THE REGION
THURSDAY AND FRIDAY. MEANWHILE MODELS DROP MORE ENERGY INTO THE
ERN U.S. H5 TROF ON FRIDAY...CREATING A CUTOFF H5 LOW OVER THE
MID MS VALLEY. THIS MIGHT ACT TO LOWER THE CHANCE OF PCPN OVER
THE WEEKEND.
THE GFS IS STILL THE QUICKEST WITH THE RETURN FLOW OF MOISTURE ON
SATURDAY. KEPT A 20 TO 30 PERCENT CHC ON THE SOUTH AND SOUTHWEST
FOR SATURDAY. AS THE UPPER LOW DRIFTS SLOWLY E...SCT PCPN REMAINS
A POSSIBILITY ON SUNDAY WITH A BETTER CHANCE ON MONDAY AS AN
INVERTED SFC TROF FOCUS THE MOISTURE ACROSS THE REGION.
HIGHS WILL SLOWLY MODERATE...RISING FROM THE MID TO UPPER 70S ON
THURSDAY TO THE 80S OVER THE WEEKEND. LOWS WILL RISE FROM THE MID
TO UPPER 50S FRIDAY MORNING INTO THE 60S FOR THE WEEKEND.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING ACROSS
THE AREA EARLY THIS MORNING. THIS IS AHEAD OF A COLD FRONT THAT
WILL PUSH DOWN ACROSS THE REGION THROUGH LATE MORNING. THE SHOWERS
HAVE BEEN SHOWING A DECREASING TREND OVER THE LAST SEVERAL HOURS
AND THE LAST FEW RUNS OF THE HRRR AND THE 00Z NAM ARE PICKING UP
ON THIS. AS A RESULT...CHANCES OF SEEING PCPN AT THE ACTUAL TAF
SITES MAY BE RELATIVELY LOW...WITH A BETTER CHANCE OF
REDEVELOPMENT SOUTHEAST OF THE TAF SITES LATER THIS MORNING. CIGS
ARE GENERALLY RUNNING VFR AT THE MOMENT BUT DO EXPECT TO SEE THEM
DROP DOWN INTO MVFR CATEGORY LATER THIS MORNING AS WE START TO GET
INTO SOME LOW LEVEL CAA. ANY LOWER CLOUDS WILL SLOWLY LIFT INTO A
VFR DECK THROUGH LATE MORNING/EARLY AFTERNOON.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
144 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST AND CROSS THE OHIO VALLEY TONIGHT. HIGH
PRESSURE AND A COOLER...DRIER AIRMASS WILL THEN SETTLE INTO THE
AREA FOR THE MID TO LATER PART OF THE WEEK. THIS HIGH WILL SLOWLY
ERODE AT THE START OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WITH THUNDERSTORMS HAVING BLOSSOMED IN A VERY MOIST AIRMASS THIS
EVENING...HAVE INCREASED POPS TO LIKELY OVER MUCH OF THE AREA.
ADDITIONAL THUNDERSTORMS WILL BE LIKELY LATE TONIGHT AS A COLD
FRONT MAKES ITS WAY ACROSS THE AREA FROM THE NORTHWEST.
TEMPERATURES WILL NOT FALL OFF MUCH TONIGHT...WITH LOWS AROUND 70.
A FEW MARGINALLY STRONG THUNDERSTORMS ARE DEVELOPING. WITH A HIGH
WET BULB ZERO HEIGHT INDICATING A LIMITED LARGE HAIL
POTENTIAL...AND WITH WINDS ALOFT BEING A BIT WEAK...MAIN THREAT
APPEARS TO BE HEAVY RAIN...ESPECIALLY WITH PRECIPITABLE WATER
BEING OVER 2 INCHES ACROSS THE SOUTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
THINGS WILL DRY OUT NICELY BEHIND THE FRONT AND HIGH TEMPERATURES
WILL BE IN THE 70S WITH NIGHTTIME LOWS DROPPING INTO THE LOW TO
MID 50S UNDER GENERALLY CLEAR SKIES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
PERIOD BEGINS WITH A HIGH PRESSURE AREA STRETCHING ACROSS THE
OHIO VALLEY. THE HIGH WILL REMAIN ANCHORED OVER THE REGION
THURSDAY AND FRIDAY. MEANWHILE MODELS DROP MORE ENERGY INTO THE
ERN U.S. H5 TROF ON FRIDAY...CREATING A CUTOFF H5 LOW OVER THE
MID MS VALLEY. THIS MIGHT ACT TO LOWER THE CHANCE OF PCPN OVER
THE WEEKEND.
THE GFS IS STILL THE QUICKEST WITH THE RETURN FLOW OF MOISTURE ON
SATURDAY. KEPT A 20 TO 30 PERCENT CHC ON THE SOUTH AND SOUTHWEST
FOR SATURDAY. AS THE UPPER LOW DRIFTS SLOWLY E...SCT PCPN REMAINS
A POSSIBILITY ON SUNDAY WITH A BETTER CHANCE ON MONDAY AS AN
INVERTED SFC TROF FOCUS THE MOISTURE ACROSS THE REGION.
HIGHS WILL SLOWLY MODERATE...RISING FROM THE MID TO UPPER 70S ON
THURSDAY TO THE 80S OVER THE WEEKEND. LOWS WILL RISE FROM THE MID
TO UPPER 50S FRIDAY MORNING INTO THE 60S FOR THE WEEKEND.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING ACROSS
THE AREA EARLY THIS MORNING. THIS IS AHEAD OF A COLD FRONT THAT
WILL PUSH DOWN ACROSS THE REGION THROUGH LATE MORNING. THE SHOWERS
HAVE BEEN SHOWING A DECREASING TREND OVER THE LAST SEVERAL HOURS
AND THE LAST FEW RUNS OF THE HRRR AND THE 00Z NAM ARE PICKING UP
ON THIS. AS A RESULT...CHANCES OF SEEING PCPN AT THE ACTUAL TAF
SITES MAY BE RELATIVELY LOW...WITH A BETTER CHANCE OF
REDEVELOPMENT SOUTHEAST OF THE TAF SITES LATER THIS MORNING. CIGS
ARE GENERALLY RUNNING VFR AT THE MOMENT BUT DO EXPECT TO SEE THEM
DROP DOWN INTO MVFR CATEGORY LATER THIS MORNING AS WE START TO GET
INTO SOME LOW LEVEL CAA. ANY LOWER CLOUDS WILL SLOWLY LIFT INTO A
VFR DECK THROUGH LATE MORNING/EARLY AFTERNOON.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...CONIGLIO/FRANKS
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS NORMAN OK
352 AM CDT TUE AUG 13 2013
.DISCUSSION...
MOIST CONVECTION HAS INCREASED ALONG THE 925 MB BAROCLINIC ZONE
EARLY THIS MORNING. THE NAM12 AND RUC13 ARE DEPICTING THIS VERY
WELL...AND INDICATE THE BEST WAA WILL OCCUR BETWEEN NOW THROUGH
ABOUT 12Z BEFORE THE FRONT BEGINS TO NUDGE SOUTHWARD. SLOW MOVING
STORMS ALONG THIS ZONE...TRAINING...AND VERY HIGH PWATS (OUN 00Z
1.92 IN) WILL SUPPORT HIGH RAINFALL RATES THROUGH EARLY THIS
MORNING. BY THIS AFTERNOON AND EVENING...A SHORTWAVE TROUGH MOVING
OUT OF KS WILL MOST LIKELY RESULT IN REDEVELOPMENT ACROSS MUCH
OF THE AREA. THE HEAVIEST RAIN IS EXPECTED ACROSS PORTIONS OF
SOUTHERN OK THIS AFTERNOON AND EVENING...AND PERHAPS EVEN W N TX
NEAR THE BOUNDARY LATE TONIGHT. THEREFORE...WILL EXTEND FFA
SOUTHWARD TO INCLUDE SOUTHERN PORTIONS OF OK WHERE SOME LOCALIZED
HEAVY RAINFALL ALREADY OCCURRED YESTERDAY. RAIN CHANCES WILL SHIFT
SOUTHWARD WITH THE BOUNDARY LATE TONIGHT THROUGH EARLY WED
MORNING. WILL KEEP MAX TEMPS CLOSE TO THE MET GUIDANCE FOR TODAY
CONSIDERING PERSISTENT STRATUS AND PRECIP CHCS THROUGH THE DAY.
SOME PARTS OF THE OKC METRO MAY NOT MAKE IT OUT OF THE 70S.
A SFC RIDGE WILL EXTEND THROUGH THE FA FROM THE NE WED BEHIND THE
FRONT KEEPING TEMPS WELL BELOW NORMAL. NORTHERLY FLOW ALOFT WILL
CONTINUE OVERHEAD THROUGH THE WORK WEEK...WITH THE POSSIBILITY OF
ADDITIONAL SUBTLE SHORTWAVE TROUGHS MOVING OVER THE PLAINS. POPS
WILL INCREASE AGAIN ON THURSDAY AS ONE SUCH WAVE TRAVERSES THE
REGION. AN EVEN MORE SIGNFICANT MID TO UPPER SHORTWAVE TROUGH IS
ANTICIPATED BY FRIDAY SO DECIDED TO INCREASE POPS TO AT LEAST CHC.
OVERALL...EXPECT AN UNUSUALLY COOL AND MOIST FORECAST THROUGH THE
ENTIRE FORECAST PERIOD AS NORTHERLY MID LEVEL FLOW REMAINS IN
PLACE WITH THE UPPER RIDGE AXIS WEST OF THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 81 69 83 67 / 80 40 20 10
HOBART OK 84 69 86 68 / 70 40 30 10
WICHITA FALLS TX 96 73 89 70 / 50 60 40 20
GAGE OK 80 65 82 64 / 60 40 20 20
PONCA CITY OK 82 66 82 64 / 50 40 20 10
DURANT OK 90 73 87 67 / 70 60 50 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OKZ004>032-040>043-
047-048.
TX...NONE.
&&
$$
02/03
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1200 AM CDT TUE AUG 13 2013
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH AT LEAST 18Z TUESDAY...WITH THE
POTENTIAL FOR TSRA TOMORROW AFTERNOON FIRST AT CDS...AND LATER AT
LBB. THESE STORMS WILL BE MADE POSSIBLE IN PART BY A PASSING COLD
FRONT...THE TIMING OF WHICH IS STILL RELATIVELY UNCERTAIN.
CONFIDENCE IS HIGHER IN TSRA AT CDS...WITH LOWER PROBABILITIES AT
LBB OWING TO THE UNCERTAINTIES RELATED TO THE TIMING OF THE
FRONTAL PASSAGE. PERIODIC MVFR CONDITIONS WILL BE POSSIBLE IF
STORMS DRIFT OVER EITHER TERMINAL...BUT OPTED TO LEAVE OUT
EXPLICIT MENTION UNTIL THE TIMING OF THUNDERSTORM ACTIVITY BECOMES
MORE CLEAR.
&&
PREV DISCUSSION... /ISSUED 346 PM CDT MON AUG 12 2013/
SHORT TERM...
WEATHER PATTERN OVER THE NEXT DAY WILL BE LARGELY DRIVEN BY
ELONGATED UPPER HIGH ALONG THE GULF COAST WITH A RIDGE EXTENDING
FROM AROUND THESE PARTS UP TO THE CANADIAN PRAIRIES. MONSOON
MOISTURE CONTINUES TO WRAP AROUND THE PERIPHERY OF THE HIGH CENTER
GENERALLY STREAMING FROM NORTHEASTERN NEW MEXICO TO THE TEXAS
PANHANDLE AND BEYOND. AREA OF SYNOPTIC SCALE LIFT IS EVIDENT TO OUR
NORTH AND NORTHWEST AND THIS IS WHERE TSTM ACTIVITY INITIATED.
HOWEVER...TO THE SOUTH...ACROSS OUR REGION...AXIS OF THETA-E MAXIMA
HAS HELPED INITIATE ISOLATED CONVECTION FROM DORA TO MEMPHIS. GIVEN
THAT THESE SHOWERS DEVELOPED BY 2PM...INDICATIONS ARE THAT THE
ATMOSPHERE IS SUFFICIENTLY MOIST TO SUPPORT AT LEAST SCATTERED STORMS
FOR MUCH OF THE AFTERNOON INTO THE EVENING HOURS...FAVORING THE
NORTHERN HALF OF THE AREA. AN INTERESTING SOLUTION IS EVIDENT IN
THE HRRR WITH CONVECTION FORMING OUT NORTHWEST OF LUBBOCK AND MOVING
SLOWLY THIS WAY...BUT PERHAPS NOT REACHING THE CITY. GIVEN THAT
THIS SOLUTION IS SOMEWHAT REPRESENTED IN LOCATION / THOUGH NOT
COVERAGE / HAVE EXPANDED POPS SOUTHWARD THIS EVENING. LIKE THE PAST
SEVERAL NIGHTS...LOW-END SEVERE STORMS WILL BE POSSIBLE WITH
CONDITIONS WANING TUESDAY MORNING FOR A WHILE. A BACK DOOR FRONT
IS INDICATED BY GUIDANCE AND WITH THE ALREADY PLENTIFUL CONVECTION
ACROSS THE PANHANDLE...PREFER THE QUICKER SOLUTION AND AS SUCH
HAVE BROUGHT THE BOUNDARY...AND ASSOCIATED INCREASED RAIN
CHANCES...INTO OUR CWFA DURING THE AFTERNOON ON TUESDAY.
LONG TERM...
MID-LEVEL PATTERN WILL CONTINUE TO AMPLIFY INTO THE EXTENDED WITH
STRONGER NW FLOW AND DEEP LAYER SHEAR ACROSS THE SOUTH PLAINS TUE
PM INTO WED IN THE WAKE OF THE FRONTAL BOUNDARY. THIS SCENARIO
SHOULD SUPPORT CONTINUED WIDESPREAD PRECIP CHANCES AS MOST MODELS
SUPPORT SOME Q-G LIFT ALONG WITH FRONTOGENETICAL FORCING CENTERED
OVER ERN NM INTO THE WRN SOUTH PLAINS. FAVORABLE 700MB THETA-E AXIS ALSO
REMAINS IN PLACE WITH PWATS INCREASING THROUGH THE FIRST COUPLE OF
DAYS OF THE EXTENDED PERIOD AS WELL. ONE LIMITING FACTOR FOR
CONSIDERATION FOR INCREASED COVERAGE WITH TIME IS THE INSTABILITY
DURING THE DAY WED. EXPECT CONSIDERABLE CLOUDINESS AND UPSLOPE
FLOW TO INHIBIT WARMING AND SUBSTANTIAL CAPE HOWEVER DEEPLY MOIST
ATMOSPHERE SHOULD AID DEVELOPMENT LOCALLY. ADDITIONAL HEATING
ACROSS EASTERN NM COUPLED WITH AMPLE SHEAR SHOULD HELP SOME
ACTIVITY TO ORGANIZE AND MOVE ACROSS THE WESTERN HALF OF THE AREA
AGAIN LATE EVENING AND OVERNIGHT WED NIGHT. SUBTLE SHORTWV
ACTIVITY TRAVERSING THE NW FLOW WILL HELP SUSTAIN AFTN STORMS THU
IN CONTINUED LIGHT UPSLOPE FLOW. ONCE AGAIN UNCAPPED ATMOSPHERE WILL
ALLOW SHOWERS TO FORM EARLY AND PREVENT THINGS FROM BECOMING TOO
UNSTABLE WITH SEVERE THREAT LIMITED OUTSIDE OF SOME HEAVY RAINERS.
FLOW TURNS MORE NRLY ON FRI AS RIDGE BUILDS FROM 4 CORNERS INTO
MONTANA. GFS AND EURO BOTH SUPPORT UPPER LOW DROPPING INTO THE MO
VALLEY ON SAT TO MAINTAIN SOME LIFT WITHIN REMNANT MOIST AXIS ON
EASTERN SIDE OF THE RIDGE. WITH CONTINUED ISOLD-SCT CONVECTION
POSSIBLE HAVE KEPT POPS GOING INTO THE WEEKEND WITH LITTLE TO NO
OVERALL WARMING TREND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 89 65 81 61 / 20 30 50 50 40
TULIA 65 89 67 80 62 / 20 30 50 50 40
PLAINVIEW 66 91 68 80 63 / 20 30 40 50 40
LEVELLAND 70 94 68 84 65 / 10 20 30 50 40
LUBBOCK 70 93 69 83 65 / 10 20 30 50 40
DENVER CITY 72 92 65 88 66 / 10 10 20 40 40
BROWNFIELD 73 94 70 86 66 / 10 10 20 50 40
CHILDRESS 72 96 69 84 67 / 20 40 50 50 30
SPUR 75 97 74 86 68 / 20 20 30 50 40
ASPERMONT 76 99 75 89 69 / 20 20 30 50 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/16
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
346 AM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENTLY...LOOKING AT MOSAIC RADAR...OUR CWFA IS PRETTY MUCH ECHO
FREE WITH A LINE OF THUNDERSTORMS PUSHING SOUTHEAST IN CENTRAL
NEBRASKA AT 1 AM THIS MORNING. FRONTAL BOUNDARY STILL LAYS UP
ALONG THE LARAMIE RANGE THIS MORNING...EXTENDING NORTHWEST INTO
CENTRAL MONTANA. TO OUR NORTH...A COMPLEX OF THUNDERSTORMS LAYS ACROSS
EASTERN MONTANA JUST EAST OF THE FRONT.
IT REMAINS TO BE SEEN WHAT THAT LINE OF THUNDERSTORMS OVER
NEBRASKA WILL DO TO OUR LOW LEVEL MOISTURE. IT HAS CAUSED WINDS TO
BECOME MORE SOUTHWESTERLY AND THEREFORE A LITTLE DRIER IN THE
PANHANDLE SO FAR. LATEST 11U-3.9U SATELLITE IMAGERY HAS YET TO
SHOW THE ANTICIPATED STRATUS DEVELOPING YET.
THE MORNING SHOULD START OFF DRY WITH INCREASING SHOWERS AND
THUNDERSTORMS DEVELOPING BY NOON. LATEST HRRR COMPOSITE
REFLECTIVITY FORECAST HAS SHOWERS DEVELOPING OVER THE MOUNTAINS TO
THE WEST OF CHEYENNE BY 17Z AND REALLY INCREASING IN COVERAGE
AFTER 19Z. THIS CORRESPONDS WELL WITH THE 00Z ECMWF FORECAST FOR
THE UPPER VORT MAX TO MOVE THROUGH THE UPPER RIDGE THIS AFTERNOON.
FORECAST STORM MOTIONS THIS AFTERNOON ON THE NAM SOUNDINGS SHOW
STORMS TO BE ALMOST STATIONARY. SOME LOCATIONS ARE GOING TO SEE
SOME HEAVY RAINFALL...LIKELY LEADING TO SOME FLASH FLOODING.
CONFIDENCE NO HIGH ON WHERE THESE THUNDERSTORMS ARE GOING TO
DEVELOP...SO WILL HOLD OFF ON ANY WATCHES. BUT DO EXPECT US TO BE
ISSUING FLASH FLOOD WARNINGS FOR SOME AREAS TODAY.
UPPER VORT MAX STAYS WITH US THROUGH THE OVERNIGHT HOURS
TONIGHT...FINALLY EXITING SOUTHEAST WEDNESDAY AFTERNOON. DID KEEP
FAIRLY HIGH POPS GOING TONIGHT THROUGH AT LEAST MIDNIGHT...THEN
PICKING UP AGAIN WEDNESDAY AFTERNOON WITH DAYTIME HEATING.
PATTERN CHANGE THEN BEGINS WEDNESDAY NIGHT INTO THURSDAY AS THE
ECMWF BUILDS THE UPPER LEVEL RIDGE. WITH THE BUILDING RIDGE...THE
DRIER AIR OVER UTAH AND SOUTHERN COLORADO WILL FILTER INTO THE
AREA DURING THE DAY THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 242 AM MDT TUE AUG 13 2013
ALL LONG RANGE MODELS IN AGREEMENT...SHOWING A BREAK IN THE
PERSISTENT MOIST WEATHER PATTERN ACROSS THE FORECAST AREA LATE
THIS WEEK. A DRYING TREND WILL CONTINUE THROUGH SATURDAY WITH
WARMER TEMPERATURES IN THE 80S AND LOW 90S EXPECTED. THE WARMEST
DAY WILL LIKELY BE SATURDAY AS THE RIDGE AXIS SHIFTS EASTWARD INTO
THE PLAINS...WITH HIGHS IN THE MID 80S TO MID 90S
EXPECTED...WARMEST ACROSS THE LOWER ELEVATIONS BELOW 5000 FEET.
KEPT POP BELOW 10 PERCENT WITH LIMITED CLOUD COVER. KEPT
TEMPERATURES A FEW DEGREES BELOW MOS FOR NOW...SINCE IT IS UNCLEAR
HOW THE CURRENT SOIL MOISTURE WILL IMPACT TEMPERATURES AND
HUMIDITY. WITH LIGHT WINDS EXPECTED...DO NOT BELIEVE THE NEAR
SURFACE MOISTURE WILL BE ADVECTED EASTWARD AS THAT QUICK.
PRECIPITATION CHANCES WILL RETURN TO THE AREA BY LATE SUNDAY AND
INTO MONDAY OF NEXT WEEK AS A FAST MOVING PACIFIC TROUGH PUSHES
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SOME COOLER AIR WILL PUSH
INTO THE REGION AS WELL WITH HIGH TEMPERATURES 5 TO 10 DEGREES
COOLER COMPARED TO FRIDAY/SATURDAY. INCREASED POP BETWEEN 20 TO 40
PERCENT FOR SHOWERS AND TSTORMS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 944 PM MDT MON AUG 12 2013
THROUGH 07Z...ISOLATED SHOWERS EAST OF A DOUGLAS TO CHEYENNE LINE.
FROM 10Z TO 16Z...AREAS OF LOW CLOUDS AND FOG AT NEBRASKA
AERODROMES WITH LOCALIZED IFR AND MVFR...VFR ELSEWHERE. AFTER 20Z
TUESDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
PRODUCING LOCALIZED MVFR.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENT THINKING IS THAT FIRE WEATHER CONCERNS WILL BE MINOR TODAY
AND WEDNESDAY AS MONSOONAL MOISTURE OVER WYOMING WILL CREATE
WIDESPREAD WETTING RAINS FOR MOST LOCATIONS. DRIER AIR BEGINS TO
MOVE INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. AFTERNOON
HUMIDITIES FORECAST TO BE IN THE SINGLE DIGITS ACROSS CARBON
COUNTY THURSDAY AFTERNOON. WINDS ARE EXPECTED TO REMAIN FAIRLY
LIGHT THOUGH AND SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
845 AM MDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 841 AM MDT TUE AUG 13 2013
HAVE CUT BACK POPS TO ZEROS...BASED ON NEAR ZERO CLOUDS ACROSS
THE CWA. WILL SEE A SLOW BUT STEADY INCREASE IN CONVECTION BY
THIS AFTERNOON...FIRST ACROSS THE MTS AND THEN SPREADING EWD TO
THE PLAINS. LOOKS LIKE A PRETTY TYPICAL AUG DAY. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM MDT TUE AUG 13 2013
...FLASH FLOOD THREAT FOR BURN SCARS IN EL PASO/TELLER COUNTIES TODAY...
MOST OF SHOWER/TSTORM ACTIVITY HAS DIMINISHED ACROSS THE AREA THIS
MORNING AND MODELS ARE HAVING A DIFFICULT TIME WITH THIS AS BOTH
NAM12 AND GFS MAINTAIN PRECIPITATION ACROSS THE SOUTHEAST PLAINS
THROUGH THE MORNING HOURS. THIS LEADS TO LOWER CONFIDENCE IN QPF
FORECAST TODAY AS MODELS PLAY CATCH UP WITH WHAT IS CURRENTLY GOING
ON.
IN WV PICS...APPEARS MAIN SHORTWAVE WHICH HELPED FIRE OFF
YESTERDAY`S CONVECTION HAS ALREADY PUSHED EAST OF THE AREA INTO
CENTRAL KS. HOWEVER...ANOTHER SHORTWAVE IS EVIDENT IN THE MOISTURE
PLUME ACROSS NW CO/SRN WY...WHICH WILL BE TRANSLATING SLOWLY
EASTWARD THROUGH THE UPPER RIDGE ACROSS THE AREA TODAY. AT THE
SFC...DEW POINTS HAVE INCREASED ACROSS THE PLAINS WITH READINGS
MAINLY IN THE 50S. STRATUS IS NOT AS WIDESPREAD AS MODELS
PORTRAYED...PROBABLY A RESULT OF THEIR OVERZEALOUS QPF FORECAST THIS
MORNING. SUSPECT WE WILL SEE SOME STRATUS DEVELOP AND SPREAD
WESTWARD INTO SOUTHEAST PLAINS TOWARDS DAWN BUT IT WILL PROBABLY BE
FAIRLY SHALLOW AND MORE PATCHY IN NATURE EXCEPT ACROSS THE SE CORNER
WHERE IT MAY BE MORE WIDESPREAD. THUS ANY STRATUS WILL LIKELY BURN
OFF FAIRLY QUICKLY THIS MORNING. WITH MORE CLEARING THIS
AFTERNOON...WE WILL BE MORE LIKELY TO SEE SUFFICIENT HEATING TO
TRIGGER ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHEAST MOUNTAINS AND ADJACENT PLAINS. WITH LOW LEVEL FLOW
REMAINING EASTERLY...DEW POINTS SHOULD REMAIN IN THE 50S ACROSS THE
PLAINS/I-25 CORRIDOR. THIS WILL LEAD TO CAPE VALUES GENERALLY
BETWEEN 500-1000 J/KG...NOT TERRIBLY HIGH...BUT SUFFICIENT TO
PRODUCE A FEW STRONG STORMS. THUS GREATEST CONCERN WILL BE THE EL
PASO/TELLER COUNTY AREAS WHERE THE SUSCEPTIBLE BURN SCARS WILL BE
UNDER THE GUN FOR MORE HEAVY RAINFALL TODAY. ALTHOUGH NAM12 HAS
TAMED DOWN ITS QPF FCST FOR TODAY VS YESTERDAY`S RUNS...OTHER MODELS
SUCH AS GFS...HIGH RES WRF (LOCAL AND NSSL)AND HRRR BOTH HIT
PORTIONS OF THE SE MTS/ADJACENT PLAINS WITH POCKETS OF HEAVY
RAINFALL. WITH THE SATURATED GROUND FROM RECENT RAINS ACROSS TELLER
AND EL PASO COUNTY...WILL BE PUTTING OUT ANOTHER FLASH FLOOD WATCH
FOR TODAY. GREATEST THREAT WINDOW APPEARS TO BE FROM 2 PM TO 6 PM
FOR THE BURN SCARS THOUGH HRRR SEEMS TO BE TRENDING IT TOWARDS 1 PM
IN SOME OF ITS LATER RUNS. OF COURSE IF THE STRONGER STORMS PASS
AROUND THE BURN SCARS...THEN IT IS POSSIBLE THAT FLASH FLOODING WILL
NOT OCCUR...BUT WILL ERR ON THE SIDE OF CAUTION AS THE PROBABILITY
WILL BE THERE FOR A HIGH IMPACT EVENT SHOULD THE BURN SCARS BE
IMPACTED. THE CITY OF COLORADO SPRINGS COULD ALSO BE UNDER THE GUN
TODAY FOR FLASH FLOODING DUE TO THE SATURATED GROUND FROM
YESTERDAY`S HEAVY RAIN WHICH WILL EXACERBATE ANY RUNOFF TODAY SHOULD
STORMS HIT THAT REGION.
THUNDERSTORMS SHOULD SPREAD EASTWARD ACROSS THE PLAINS DURING THE
LATE AFTERNOON AND EVENING HOURS AS THE SHORTWAVE SLOWLY KICKS
THROUGH THE REGION. WILL DECREASE POPS QUICKLY AFTER 06Z AS
CONSENSUS OF THE MODELS IS TO KEEP CONVECTION GOING WELL TO THE
SOUTH ALONG FRONTAL BOUNDARY ACROSS EASTERN NM/SRN TX PANHANDLE.
GFS SEEMS TO BE THE OUTLIER IN KEEPING WIDESPREAD QPF ACROSS THE
PLAINS THROUGH 12Z...SO WILL DISCOUNT IT FOR NOW. STRATUS SHOULD BE
MORE WIDESPREAD ACROSS THE SE PLAINS TONIGHT.
NOT TO NEGLECT WESTERN AREAS...DRIER AIR OUT THAT WAY SHOULD KEEP
PCPN EFFICIENCIES WITH THUNDERSTORMS LOWER. PRECIP WATERS WILL BE
RUNNING AROUND .50 WHICH PUTS THEM BELOW 100% OF NORMAL. WITH
FORCING FROM THE SHORTWAVE EXPECTED TO IMPACT NORTHERN AREAS MORE SO
THAN THE SOUTHWEST...EXPECT THUNDERSTORMS TO BE MORE ISOLATED TO
SCATTERED IN COVERAGE ACROSS THE EASTERN SAN JUANS AND LA
GARITAS...AND WILL DIMINISH QUICKLY DURING THE EVENING HOURS. THE
WEST FORK BURN SCAR WILL NEED TO BE MONITORED FROM NOON TO 6 PM FOR
POCKETS OF HEAVIER RAIN SUFFICIENT TO CAUSE LOCALIZED
RUNOFF/POTENTIAL FLASH FLOOD PROBLEMS. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 528 AM MDT TUE AUG 13 2013
LONGER TERM METEOROLOGICAL CONCERNS INCLUDE POPS AND TEMPERATURES.
ABOVE SEASONAL POPS IN COMBINATION WITH BELOW SEASONAL TEMPERATURES
ARE EXPECTED FROM WEDNESDAY INTO WEDNESDAY NIGHT AS AVAILABLE
ATMOSPHERIC MOISTURE INTERACTS WITH THE DAILY OROGRAPHIC HEATING
CYCLE AS WELL AS SOME UPPER LIFT.
RECENT LONGER TERM FORECAST MODEL SOUNDINGS INDICATE THAT
LOCATIONS SUCH AS THE I-25 CORRIDOR SHOULD EXPERIENCE PRECIPITABLE
WATER VALUES NEARING ONE INCH AT TIMES WEDNESDAY AFTERNOON.
THE COMBINATION OF AVAILABLE ATMOSPHERIC MOISTURE AND AN
APPROACHING UPPER SHORT-WAVE(PER LATEST GFS40 PV15 FORECAST)
...ESPECIALLY OVER NORTHERN SECTIONS OF THE FORECAST DISTRICT
SHOULD ALLOW FOR ANOTHER ROUND OF ISOLATED TO SCATTERED WEDNESDAY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE FORECAST
DISTRICT...ESPECIALLY EASTERN SECTIONS.
ONCE AGAIN...SOME OF THESE STORMS ON WEDNESDAY AFTERNOON AND
EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AS
WELL AS POTENTIAL BURN SCAR FLOODING ISSUES...ESPECIALLY IF A
STRONGER STORM DEVELOPS OVER A BURN SCAR...SUCH AS THE WALDO
CANYON BURN SCAR...ETC. WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY AND ISSUE HYDRO/FLASH FLOOD HIGHLIGHTS/ADVISORIES/WARNINGS
AS NEEDED.
THEN...WARMER AND DRIER CONDITIONS SHOULD RETURN TO THE FORECAST
DISTRICT FROM LATER THURSDAY INTO AT LEAST EARLY SUNDAY AS AN
UPPER RIDGE BUILDS OVER ARIZONA AND NEW MEXICO. IN ADDITION...
FORECAST PRECIPITABLE WATER VALUES DROP TO BETWEEN 0.50 AND 0.70
INCHES OVER THE INTERSTATE 25 CORRIDOR DURING THIS TIME-FRAME.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
SHOULD BE NOTED OVER THE CWFA FROM LATER THURSDAY INTO EARLY
SUNDAY. EVEN THOUGH RELATIVELY UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM IMPACTS A
BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
IN ADDITION...STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO
DEVELOP OVER PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS FROM
THURSDAY INTO THURSDAY EVENING AS PROJECTED LOCALIZED CAPES/LIS IN
EXCESS OF 2000 J/KG AND -7C RESPECTIVELY INTERACT WITH PROJECTED
0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY IS THEN ANTICIPATED
FROM LATER SUNDAY INTO NEXT TUESDAY AS A NORTHERLY SURFACE SURGE
MOVING ACROSS EASTERN SECTIONS MONDAY INCREASES ATMOSPHERIC
MOISTURE AND INTERACTS WITH UPPER SHORTWAVES. FORECAST MODEL
SOUNDINGS PROJECT THAT PRECIPITABLE WATER VALUES OVER THE
INTERSTATE 25 CORRIDOR INCREASE TO OVER ONE INCH BY MONDAY
AFTERNOON.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR LOCALIZED
HEAVY RAIN AND ASSOCIATED FLASH FLOODING CONCERNS(ESPECIALLY OVER
THE AREA BURN SCARS) WILL BE POSSIBLE FROM LATER SUNDAY INTO NEXT
TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY.
FINALLY...LOW-GRADE GRADIENT WINDS AS WELL AS ABOVE AVERAGE
MID-AUGUST SEASONAL TEMPERATURES ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO NEXT MONDAY
WITH THE WARMEST CONDITIONS EXPECTED THIS WEEKEND AS 700 MB
TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB TO AROUND 18C FROM THE
12C READINGS PROJECTED TODAY. MAXIMUM TEMPERATURES THIS WEEKEND
OVER MANY SECTIONS OF THE SOUTHEASTERN COLORADO PLAINS SHOULD
REACH WELL INTO THE 90S BOTH SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 528 AM MDT TUE AUG 13 2013
THERE IS THE POTENTIAL FOR SOME MVFR TO IFR CIGS TO BRIEFLY FORM
OVER KCOS THIS MORNING DUE TO HEAVY RAINFALL FROM YESTERDAY AND
MOIST AIRMASS. DOESN`T APPEAR TO BE A STRONG EASTERLY PUSH OF
THE LOW LEVEL WINDS THOUGH TO HELP GET MORE WIDESPREAD STRATUS TO
DEVELOP...SO THIS IS LIKELY TO REMAIN MORE SPOTTY IN COVERAGE AND
WILL MONITOR LATEST SATELLITE TRENDS FOR THE NEED TO INCLUDE IN
TAF. PLAN TO MAINTAIN SCT012 LAYER UNLESS TRENDS SUGGEST
OTHERWISE. PROBABILITY FOR STRATUS LOOKS LESS LIKELY FOR KPUB BUT
NOT ENTIRELY NIL. SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AROUND NOON...AND MAY AFFECT THE TAF SITES AFTER 20Z. KCOS
APPEARS TO HAVE THE BEST CHANCE FOR -TSRA THIS AFTERNOON. COULD SEE
SOME BRIEF MVFR/IFR CIGS/VIS WITH THE STRONGER STORMS.
THUNDERSTORMS THREAT SHOULD DIMINISH RAPIDLY AFTER 00Z-01Z WITH A
SLIGHTLY BETTER CHANCE FOR MVFR TO IFR STRATUS TO DEVELOP ALONG THE
I-25 CORRIDOR TOWARDS 12Z WED. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH THIS EVENING FOR
COZ081-084-085.
&&
$$
UPDATE...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
528 AM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM MDT TUE AUG 13 2013
...FLASH FLOOD THREAT FOR BURN SCARS IN EL PASO/TELLER COUNTIES TODAY...
MOST OF SHOWER/TSTORM ACTIVITY HAS DIMINISHED ACROSS THE AREA THIS
MORNING AND MODELS ARE HAVING A DIFFICULT TIME WITH THIS AS BOTH
NAM12 AND GFS MAINTAIN PRECIPITATION ACROSS THE SOUTHEAST PLAINS
THROUGH THE MORNING HOURS. THIS LEADS TO LOWER CONFIDENCE IN QPF
FORECAST TODAY AS MODELS PLAY CATCH UP WITH WHAT IS CURRENTLY GOING
ON.
IN WV PICS...APPEARS MAIN SHORTWAVE WHICH HELPED FIRE OFF
YESTERDAY`S CONVECTION HAS ALREADY PUSHED EAST OF THE AREA INTO
CENTRAL KS. HOWEVER...ANOTHER SHORTWAVE IS EVIDENT IN THE MOISTURE
PLUME ACROSS NW CO/SRN WY...WHICH WILL BE TRANSLATING SLOWLY
EASTWARD THROUGH THE UPPER RIDGE ACROSS THE AREA TODAY. AT THE
SFC...DEW POINTS HAVE INCREASED ACROSS THE PLAINS WITH READINGS
MAINLY IN THE 50S. STRATUS IS NOT AS WIDESPREAD AS MODELS
PORTRAYED...PROBABLY A RESULT OF THEIR OVERZEALOUS QPF FORECAST THIS
MORNING. SUSPECT WE WILL SEE SOME STRATUS DEVELOP AND SPREAD
WESTWARD INTO SOUTHEAST PLAINS TOWARDS DAWN BUT IT WILL PROBABLY BE
FAIRLY SHALLOW AND MORE PATCHY IN NATURE EXCEPT ACROSS THE SE CORNER
WHERE IT MAY BE MORE WIDESPREAD. THUS ANY STRATUS WILL LIKELY BURN
OFF FAIRLY QUICKLY THIS MORNING. WITH MORE CLEARING THIS
AFTERNOON...WE WILL BE MORE LIKELY TO SEE SUFFICIENT HEATING TO
TRIGGER ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHEAST MOUNTAINS AND ADJACENT PLAINS. WITH LOW LEVEL FLOW
REMAINING EASTERLY...DEW POINTS SHOULD REMAIN IN THE 50S ACROSS THE
PLAINS/I-25 CORRIDOR. THIS WILL LEAD TO CAPE VALUES GENERALLY
BETWEEN 500-1000 J/KG...NOT TERRIBLY HIGH...BUT SUFFICIENT TO
PRODUCE A FEW STRONG STORMS. THUS GREATEST CONCERN WILL BE THE EL
PASO/TELLER COUNTY AREAS WHERE THE SUSCEPTIBLE BURN SCARS WILL BE
UNDER THE GUN FOR MORE HEAVY RAINFALL TODAY. ALTHOUGH NAM12 HAS
TAMED DOWN ITS QPF FCST FOR TODAY VS YESTERDAY`S RUNS...OTHER MODELS
SUCH AS GFS...HIGH RES WRF (LOCAL AND NSSL)AND HRRR BOTH HIT
PORTIONS OF THE SE MTS/ADJACENT PLAINS WITH POCKETS OF HEAVY
RAINFALL. WITH THE SATURATED GROUND FROM RECENT RAINS ACROSS TELLER
AND EL PASO COUNTY...WILL BE PUTTING OUT ANOTHER FLASH FLOOD WATCH
FOR TODAY. GREATEST THREAT WINDOW APPEARS TO BE FROM 2 PM TO 6 PM
FOR THE BURN SCARS THOUGH HRRR SEEMS TO BE TRENDING IT TOWARDS 1 PM
IN SOME OF ITS LATER RUNS. OF COURSE IF THE STRONGER STORMS PASS
AROUND THE BURN SCARS...THEN IT IS POSSIBLE THAT FLASH FLOODING WILL
NOT OCCUR...BUT WILL ERR ON THE SIDE OF CAUTION AS THE PROBABILITY
WILL BE THERE FOR A HIGH IMPACT EVENT SHOULD THE BURN SCARS BE
IMPACTED. THE CITY OF COLORADO SPRINGS COULD ALSO BE UNDER THE GUN
TODAY FOR FLASH FLOODING DUE TO THE SATURATED GROUND FROM
YESTERDAY`S HEAVY RAIN WHICH WILL EXACERBATE ANY RUNOFF TODAY SHOULD
STORMS HIT THAT REGION.
THUNDERSTORMS SHOULD SPREAD EASTWARD ACROSS THE PLAINS DURING THE
LATE AFTERNOON AND EVENING HOURS AS THE SHORTWAVE SLOWLY KICKS
THROUGH THE REGION. WILL DECREASE POPS QUICKLY AFTER 06Z AS
CONSENSUS OF THE MODELS IS TO KEEP CONVECTION GOING WELL TO THE
SOUTH ALONG FRONTAL BOUNDARY ACROSS EASTERN NM/SRN TX PANHANDLE.
GFS SEEMS TO BE THE OUTLIER IN KEEPING WIDESPREAD QPF ACROSS THE
PLAINS THROUGH 12Z...SO WILL DISCOUNT IT FOR NOW. STRATUS SHOULD BE
MORE WIDESPREAD ACROSS THE SE PLAINS TONIGHT.
NOT TO NEGLECT WESTERN AREAS...DRIER AIR OUT THAT WAY SHOULD KEEP
PCPN EFFICIENCIES WITH THUNDERSTORMS LOWER. PRECIP WATERS WILL BE
RUNNING AROUND .50 WHICH PUTS THEM BELOW 100% OF NORMAL. WITH
FORCING FROM THE SHORTWAVE EXPECTED TO IMPACT NORTHERN AREAS MORE SO
THAN THE SOUTHWEST...EXPECT THUNDERSTORMS TO BE MORE ISOLATED TO
SCATTERED IN COVERAGE ACROSS THE EASTERN SAN JUANS AND LA
GARITAS...AND WILL DIMINISH QUICKLY DURING THE EVENING HOURS. THE
WEST FORK BURN SCAR WILL NEED TO BE MONITORED FROM NOON TO 6 PM FOR
POCKETS OF HEAVIER RAIN SUFFICIENT TO CAUSE LOCALIZED
RUNOFF/POTENTIAL FLASH FLOOD PROBLEMS. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 528 AM MDT TUE AUG 13 2013
LONGER TERM METEOROLOGICAL CONCERNS INCLUDE POPS AND TEMPERATURES.
ABOVE SEASONAL POPS IN COMBINATION WITH BELOW SEASONAL TEMPERATURES
ARE EXPECTED FROM WEDNESDAY INTO WEDNESDAY NIGHT AS AVAILABLE
ATMOSPHERIC MOISTURE INTERACTS WITH THE DAILY OROGRAPHIC HEATING
CYCLE AS WELL AS SOME UPPER LIFT.
RECENT LONGER TERM FORECAST MODEL SOUNDINGS INDICATE THAT
LOCATIONS SUCH AS THE I-25 CORRIDOR SHOULD EXPERIENCE PRECIPITABLE
WATER VALUES NEARING ONE INCH AT TIMES WEDNESDAY AFTERNOON.
THE COMBINATION OF AVAILABLE ATMOSPHERIC MOISTURE AND AN
APPROACHING UPPER SHORT-WAVE(PER LATEST GFS40 PV15 FORECAST)
...ESPECIALLY OVER NORTHERN SECTIONS OF THE FORECAST DISTRICT
SHOULD ALLOW FOR ANOTHER ROUND OF ISOLATED TO SCATTERED WEDNESDAY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE FORECAST
DISTRICT...ESPECIALLY EASTERN SECTIONS.
ONCE AGAIN...SOME OF THESE STORMS ON WEDNESDAY AFTERNOON AND
EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AS
WELL AS POTENTIAL BURN SCAR FLOODING ISSUES...ESPECIALLY IF A
STRONGER STORM DEVELOPS OVER A BURN SCAR...SUCH AS THE WALDO
CANYON BURN SCAR...ETC. WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY AND ISSUE HYDRO/FLASH FLOOD HIGHLIGHTS/ADVISORIES/WARNINGS
AS NEEDED.
THEN...WARMER AND DRIER CONDITIONS SHOULD RETURN TO THE FORECAST
DISTRICT FROM LATER THURSDAY INTO AT LEAST EARLY SUNDAY AS AN
UPPER RIDGE BUILDS OVER ARIZONA AND NEW MEXICO. IN ADDITION...
FORECAST PRECIPITABLE WATER VALUES DROP TO BETWEEN 0.50 AND 0.70
INCHES OVER THE INTERSTATE 25 CORRIDOR DURING THIS TIME-FRAME.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
SHOULD BE NOTED OVER THE CWFA FROM LATER THURSDAY INTO EARLY
SUNDAY. EVEN THOUGH RELATIVELY UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM IMPACTS A
BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
IN ADDITION...STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO
DEVELOP OVER PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS FROM
THURSDAY INTO THURSDAY EVENING AS PROJECTED LOCALIZED CAPES/LIS IN
EXCESS OF 2000 J/KG AND -7C RESPECTIVELY INTERACT WITH PROJECTED
0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY IS THEN ANTICIPATED
FROM LATER SUNDAY INTO NEXT TUESDAY AS A NORTHERLY SURFACE SURGE
MOVING ACROSS EASTERN SECTIONS MONDAY INCREASES ATMOSPHERIC
MOISTURE AND INTERACTS WITH UPPER SHORTWAVES. FORECAST MODEL
SOUNDINGS PROJECT THAT PRECIPITABLE WATER VALUES OVER THE
INTERSTATE 25 CORRIDOR INCREASE TO OVER ONE INCH BY MONDAY
AFTERNOON.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR LOCALIZED
HEAVY RAIN AND ASSOCIATED FLASH FLOODING CONCERNS(ESPECIALLY OVER
THE AREA BURN SCARS) WILL BE POSSIBLE FROM LATER SUNDAY INTO NEXT
TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY.
FINALLY...LOW-GRADE GRADIENT WINDS AS WELL AS ABOVE AVERAGE
MID-AUGUST SEASONAL TEMPERATURES ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO NEXT MONDAY
WITH THE WARMEST CONDITIONS EXPECTED THIS WEEKEND AS 700 MB
TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB TO AROUND 18C FROM THE
12C READINGS PROJECTED TODAY. MAXIMUM TEMPERATURES THIS WEEKEND
OVER MANY SECTIONS OF THE SOUTHEASTERN COLORADO PLAINS SHOULD
REACH WELL INTO THE 90S BOTH SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 528 AM MDT TUE AUG 13 2013
THERE IS THE POTENTIAL FOR SOME MVFR TO IFR CIGS TO BRIEFLY FORM
OVER KCOS THIS MORNING DUE TO HEAVY RAINFALL FROM YESTERDAY AND
MOIST AIRMASS. DOESN`T APPEAR TO BE A STRONG EASTERLY PUSH OF
THE LOW LEVEL WINDS THOUGH TO HELP GET MORE WIDESPREAD STRATUS TO
DEVELOP...SO THIS IS LIKELY TO REMAIN MORE SPOTTY IN COVERAGE AND
WILL MONITOR LATEST SATELLITE TRENDS FOR THE NEED TO INCLUDE IN
TAF. PLAN TO MAINTAIN SCT012 LAYER UNLESS TRENDS SUGGEST
OTHERWISE. PROBABILITY FOR STRATUS LOOKS LESS LIKELY FOR KPUB BUT
NOT ENTIRELY NIL. SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AROUND NOON...AND MAY AFFECT THE TAF SITES AFTER 20Z. KCOS
APPEARS TO HAVE THE BEST CHANCE FOR -TSRA THIS AFTERNOON. COULD SEE
SOME BRIEF MVFR/IFR CIGS/VIS WITH THE STRONGER STORMS.
THUNDERSTORMS THREAT SHOULD DIMINISH RAPIDLY AFTER 00Z-01Z WITH A
SLIGHTLY BETTER CHANCE FOR MVFR TO IFR STRATUS TO DEVELOP ALONG THE
I-25 CORRIDOR TOWARDS 12Z WED. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH THIS EVENING FOR
COZ081-084-085.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
726 AM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND
EMBEDDED THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL LATER TODAY AND
INTO THIS EVENING. DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY
AND CONTINUES INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
***SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING LATER TODAY***
7 AM UPDATE...
FORECAST MOSTLY ON TRACK. WEAK ECHOS ON CURRENT RADAR IMG LIKELY
NOT YET HITTING THE GROUND GIVING DWPT DEPRESSIONS ABOUT 5F OR
HIGHER. TWO AREAS OF PRECIPITATION TO WATCH AND TWO SCHOOLS OF
THOUGHT BETWEEN LATEST MODEL RUNS. THE NORTHERNMOST BAND IS
ASSOCIATED WITH WEAKENING CONVECTION AHEAD OF AN APPROACHING COLD
FRONT WHILE THE SOUTHERN BAND IS MORE CLOSELY ASSOCIATED WITH A
WARM FRONT WHICH IS PROGGED TO REMAIN MOSTLY S OF THE REGION. HAVE
NOTED THAT THESE TWO BANDS WILL FORM TO MAKE A MORE COHESIVE BAND
OF RAIN WITH EMBEDDED TSRA WHICH WILL MOVE THROUGH LATE MORNING
INTO THE AFTERNOON HOURS /LATEST HRRR SHOWS THIS WELL/. HOWEVER
THE TWO OUTCOMES IN MODELS WILL NEED TO BE WATCHED. LATEST NAM
SUGGESTS THAT GIVEN BEST INSTABILITY REMAINS S...HEAVIEST RAIN AND
TSRA REMAIN S AS WELL...CUTTING OFF BEST MOISTURE AND
INSTABILITY...LEADING TO LOWER IMPACT. HOWEVER...RECENT ECMWF RUN
IS FURTHER N AND STRONGER WITH THE WAVE. BOTH ARE CURRENTLY
HANDLING PRECIP LOCATIONS/STRENGTH WELL...SO WILL NEED TO WATCH
HOW INSTABILITY AXIS SHAKES OUT OVER THE NEXT FEW HOURS. THIS MAY
DETERMINE HOW ACTIVE THE AFTERNOON IS.
ALSO...AM NOTING A SECONDARY DEVELOPMENT OF SHOWERS AND STORMS
MORE CLOSELY ASSOCIATED WITH THE FRONT FOR LATE AFTERNOON/EVENING
AFTER THIS INITIAL WEAKENING CONVECTIVE BAND MOVES OUT.
PREVIOUS DISCUSSION FOLLOWS...
CALM WINDS AND DEWPOINTS IN THE 60S HAS ALLOWED AREAS OF DENSE
FOG TO DEVELOP ALONG THE SOUTH COAST/CAPE AND ISLANDS VERY EARLY
THIS MORNING. THIS HAS PROMPTED THE ISSUANCE OF A DENSE FOG
ADVISORY THROUGH 9 AM ACROSS THIS REGION. THE FOG SHOULD BURN OFF
BY MID TO LATE MORNING.
OTHERWISE...SHOWERS AND THUNDERSTORMS HAVE BROKEN OUT EARLY THIS
MORNING ACROSS WESTERN NY/WESTERN PA AHEAD OF A STRONG SHORTWAVE.
THIS ACTIVITY WILL WORK EAST AND OVERSPREAD SOUTHERN NEW ENGLAND
LATER THIS MORNING AND EARLY AFTERNOON. CONFIDENCE IS FAIRLY HIGH
THAT THIS PRECIPITATION WILL BE WIDESPREAD...SO SHOWED AT LEAST LOW
END CATEGORICAL POPS ACROSS MOST AREAS. THERE ARE TWO MAIN CONCERNS
TODAY WHICH WE WILL OUTLINE BELOW:
1) FL0ODING POTENTIAL:
PRETTY GOOD JET DYNAMICS/FORCING ARE ASSOCIATED WITH THIS SHORTWAVE
TROUGH...SO EXPECT LOCALLY HEAVY RAINFALL AND NUISANCE POOR
DRAINAGE STREET FLOODING. WILL INCLUDE THIS WORDING IN OUR FORECAST
AND HAZARDOUS WEATHER OUTLOOK. DECIDED NOT TO ISSUE A FLASH FLOOD
WATCH AT THIS TIME FOR A COUPLE OF REASONS. THE FIRST WAS THAT
PWATS ARE HIGH...BUT GENERALLY UNDER 2 INCHES/SURFACE DEWPOINTS
SHOULD REMAIN BELOW 70 AND BETTER INSTABILITY WILL RESIDE TO OUR
SOUTH. NONETHELESS...GIVEN FAIRLY STRONG FORCING THERE IS STILL A
LOW PROBABILITY FOR VERY LOCALIZED FLASH FLOODING. LATER SHIFTS
WILL HAVE TO KEEP A CLOSE EYE ON THIS POTENTIAL IN CASE A SHORT
FUSED FLASH FLOOD WATCH IS NEEDED.
2) SEVERE WEATHER POTENTIAL:
PRETTY GOOD JET DYNAMIC WILL RESULT IN 0 TO 6 KM SHEAR VALUES ON THE
ORDER OF 35 TO 45 KNOTS TODAY. THE PROBLEM IS THAT WITH A FAIR
AMOUNT OF CLOUD COVER AND POOR MID LEVEL LAPSE RATES...INSTABILITY
WILL REMAIN QUITE LIMITED WITH MLCAPE VALUE GENERALLY UNDER 1000
J/KG. THEREFORE...THINKING THAT THE MAIN THREAT WILL BE HEAVY
RAINFALL AND POOR DRAINAGE STREET FLOODING. HOWEVER...GIVEN THAT
THE 0 TO 6 KM SHEAR WILL BE NEAR OR ABOVE 40 KNOTS WE CAN/T
COMPLETELY LET OUR GUARD DOWN. IF MORE INSTABILITY DEVELOPS THAN
EXPECTED THERE WOULD BE THE THREAT FOR A FEW SEVERE THUNDERSTORMS.
SOMETHING WILL NEED TO KEEP AN EYE ON BUT APPEARS TO BE A LOW
PROBABILITY AT THIS POINT.
&&
.SHORT TERM /WEDNESDAY/...
TONIGHT...
A FEW SHOWERS AND ISOLATED THUNDERSTORMS MAY LINGER DURING THE
EVENING ESPECIALLY ALONG THE COAST. OTHERWISE...MUCH DRIER MID
LEVEL AIR WILL WORK INTO THE REGION BY LATE EVENING BRINGING AN END
TO MOST OF THE PRECIPITATION. MAY SEE SOME PATCHY GROUND FOG
DEVELOP IN THE TYPICALLY PRONE LOCATIONS...ESPECIALLY IN AREAS THAT
SEE A FAIR AMOUNT OF RAIN TODAY. LOW TEMPS WILL MAINLY BE IN THE
UPPER 50S AND LOWER 60S.
WEDNESDAY...
A MIXTURE OF CLOUDS/SUN ALONG WITH GUSTY NORTHWEST WINDS BEHIND THE
COLD FRONT ON WED. LOW RISK OF A BRIEF SPRINKLE/SPOT SHOWER ACROSS
OUR FAR NORTHWEST ZONES...BUT BASICALLY A DRY AND BEAUTIFUL DAY
EXPECTED FOR THE MIDDLE OF AUGUST. HIGH TEMPS WILL MAINLY BE IN THE
70S WITH LOW HUMIDITY. IN FACT...SOME OF THE HIGHEST TERRAIN WILL
STRUGGLE TO REACH 70!
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER WED THRU THE WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK CUTOFF IS PROGGED TO
SLIDE INTO THE CANADIAN MARITIMES AS A SECOND CUTOFF DIVES S FROM
HUDSON BAY IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE
NORTHEAST CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND
CUTOFF LOOK TO HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING
ALONG THE SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE
ATLANTIC TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE
NORTHEAST. GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL
MODELS AND THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH
CONFIDENCE THAT THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST
THROUGH EARLY NEXT WEEK. GIVEN THIS...WILL USE A GFS/ECWMF BLEND
AS A BASELINE FOR THIS FORECAST UPDATE.
WED NIGHT INTO FRI...
HIGH PRES GRADUALLY SLIDES IN FROM THE W THROUGH THE PERIOD. WITH
THE HIGH PRES CENTER REMAINING W OF THE REGION...EXPECT US TO
REMAIN ON THE COOLER SIDE OF THE HIGH INITIALLY. H85 TEMPS RANGE
BETWEEN +8C AND ABOUT +11C...SO HIGHS SHOULD START THU AROUND THE
MID 70S...INCREASING TO THE UPPER 70S AND LOW 80S BY FRI AFTER
SOME AIRMASS MODIFICATION. OVERNIGHT MINS WILL BE ON THE COOL SIDE
WITH LOW HUMIDITY /AND THEREFORE LOW DWPTS/ WITH LIGHT FLOW AND
CLEAR SKIES. EXPECTING MINS DIPPING AS LOW AS THE MID 40S IN
NORMALLY COOLER SPOTS. MID 50S IN THE WARMER SPOTS.
THIS COMING WEEKEND...
A WARM FRONT IS EXPECTED TO BEGIN A GRADUAL SLIDE TO THE N
THROUGH THE WEEKEND...BUT WITH HIGH PRES IN PLACE OVER THE REGION
AND VERY SLOWLY SLIDING TO THE E...EXPECTING MOSTLY DRY CONDITIONS
ACROSS SRN NEW ENGLAND DESPITE THIS APPROACHING FRONT. GFS
CURRENTLY SUGGESTS HIGHEST POTENTIAL FOR SOME PRECIP...BUT IT TOO
KEEPS MOST OF ITS GENERATED QPF TO THE W. MID LVL TEMPS DO
INCREASE SOMEWHAT...REACHING +10 TO +13C...SO TEMPS LEAN NEAR TO
SLIGHTLY WARMER THAN NORMAL.
EARLY NEXT WEEK...
DIFFERENCES IN THE TIMING OF A STRONGER SHORTWAVE EFFECTING THE
REGION GIVES WAY TO LOWER CONFIDENCE HERE...BUT IT APPEARS THAT
THERE WILL BE A BIT HIGHER CHANCE FOR SOME PRECIP PARTICULARLY BY
TUE. WILL BE INCREASING TO SOME SLIGHT CHANCE POPS...CLOSER TO THE
ECWMF SOLUTION...WHICH SUGGESTS THE WARM FRONT LIFTS FAR ENOUGH N
TO AFFECT THE REGION WITH THIS SHORTWAVE PASSAGE.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
ON WEDNESDAY.
TODAY...DENSE FOG BURNS OFF IN NEXT COUPLE OF HOURS. AS A BAND OF
RAIN WITH EMBEDDED THUNDERSTORMS MOVES OVER FROM THE W FROM MID
MORNING INTO THE AFTERNOON...WILL SEE A MIX OF VFR TO IFR...WITH
THE IFR CONDITIONS MOSTLY DUE TO LOW VISIBILITIES IN POCKETS OF
HEAVIER RAIN. EXACT TIMING REMAINS UNCERTAIN.
TONIGHT...LEFT OVER SHOWERS/ISOLATED THUNDERSTORMS
THIS EVENING. OTHERWISE...MAY SEE SOME LINGERING LOW CLOUDS AND FOG
PATCHES PERSIST AT SOME /ESPECIALLY EASTERN/ TERMINALS INTO THE
OVERNIGHT HOURS. AREAL COVERAGE OF LOW CLOUDS AND FOG PATCHES ARE
UNCERTAIN.
WEDNESDAY...ANY LEFT OVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN LATE THIS MORNING/AFTERNOON.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY AND TONIGHT...HIGH CONFIDENCE. WINDS AND SEAS WILL REMAIN
BELOW SCA THRESHOLDS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. THE MAIN CONCERN EARLY THIS MORNING WILL BE FOR DENSE FOG
ACROSS OUR SOUTHERN WATERS. THIS FOG SHOULD BURN OFF TO AT LEAST
SOME DEGREE BY MID TO LATE MORNING. THE OTHER CONCERN WILL BE FOR
EMBEDDED THUNDERSTORMS TO WORK ACROSS THE WATERS...MAINLY THIS
AFTERNOON AND EVENING.
WEDNESDAY...MODERATE CONFIDENCE. NORTHWEST WIND GUSTS OF 25 KNOTS
ARE EXPECTED NEAR SHORE WITH GOOD MIXING BEHIND THE COLD FRONT. ITS
3RD PERIOD SO DID NOT GO WITH ANY HEADLINES AT THIS POINT...BUT
LATER SHIFTS MAY NEED TO CONSIDER A SCA FOR SOME OF OUR NEAR SHORE
WATERS. MAY ALSO SEE SOME 3 TO 5 FOOT SEAS DEVELOP ACROSS OUR
SOUTHERN MOST ATLANTIC WATERS...WHICH MAY ALSO NEED TO BE CONSIDERED
FOR HEADLINES.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND THE
WATERS BUT WILL REMAIN BELOW 25 KTS...SAVE FOR POSSIBLY WED
EVENING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MAZ020>024.
NH...NONE.
RI...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR RIZ006>008.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1050 AM CDT TUE AUG 13 2013
.DISCUSSION...
1050 AM CDT
FOR MORNING UPDATE...
NO SIGNIFICANT CHANGES TO NEAR TERM FORECAST THIS MORNING. ONLY
MINOR TWEAKS TO HOURLY TEMP/SKY COVER GRIDS BASED ON CURRENT OBS AND
SATELLITE TRENDS.
SPRAWLING CANADIAN SURFACE HIGH PRESSURE CONTINUES TO BUILD
SOUTHEAST FROM THE LAKE WINNIPEG AREA OF SOUTHERN MANITOBA LATE THIS
MORNING...WITH BREEZY NORTH-NORTHEAST SURFACE WINDS AHEAD OF THE
ADVANCING ANTICYCLONE BRINGING COOLER AND DRIER ALMOST EARLY-AUTUMN
LIKE AIR TO THE FORECAST AREA. IN FACT...THE COOL AIR ALOFT...WITH
+5C SAMPLED AT 850 MB IN THE GREEN BAY WISC 12Z RAOB...HAS LED TO
DEVELOPMENT OF LAKE EFFECT STRATOCU ACROSS LAKE MICHIGAN. THIS LAKE
INDUCED CLOUD COVER WAS SPREADING INLAND INTO THE CHICAGO METRO AREA
DOWNWIND OF THE LAKE. ASSESSMENT OF THE MORNING RAOB DATA AND MODEL
LOW-LEVEL THERMAL FIELDS CONTINUES TO INDICATE A RATHER COOL DAY FOR
MID-AUGUST...WITH HIGHS RANGING FROM PERHAPS THE UPPER 60S ALONG THE
LAKE MICHIGAN SHORE...TO THE LOW-MID 70S IN THE WARMEST INLAND
REACHES SUCH AS DIXON/PONTIAC. DEW POINT TEMPS IN THE MID-UPPER 40S
WILL MAKE FOR DRY CONDITIONS THIS AFTERNOON AS WELL...AS WINDS BEGIN
TO DIMINISH WITH THE GRADIENT GRADUALLY WEAKENING WITH THE APPROACH
OF THE HIGH PRESSURE CENTER.
RATZER
&&
.PREV DISCUSSION...
327 AM CDT
WITH EXPANSIVE SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTHWEST
AND THEN ESTABLISHING ITSELF OVER THE GREAT LAKES REGION THROUGH THE
WEEKEND...THERE ARE NO REAL WEATHER CONCERNS FOR THE AREA.
HOWEVER...AN UNSEASONABLY COOL AIR MASS IS PLUNGING SOUTH DOWN LAKE
MICHIGAN BEHIND A SECONDARY COLD FRONT AND SHARP TROUGH AXIS SEEN
WELL ON WATER VAPOR IMAGERY EARLY THIS MORNING. THIS WILL QUICKLY
TRANSPORT THE MID SINGLE DIGIT 850 MB TEMPS OVER ONTARIO ON THE 00Z
RAOB TO OUR AREA BY THIS AFTERNOON...WHICH WILL MAKE FOR MORE
FALL-LIKE THAN SUMMER-LIKE HIGH TEMPERATURES PRIMARILY IN THE LOWER
70S...WITH A SCATTERING OF MID 70S READINGS IN THE FAR SOUTH AND
WEST. DESPITE A VERY DRY AIRMASS...STEEPENING LOW LEVEL LAPSE RATES
AND NEAR SATURATION AT ABOUT 800 MB WILL LIKELY RESULT IN A
BLOSSOMING STRATOCU DECK BY MID TO LATE MORNING THAT WILL GRADUALLY
DISSIPATE THROUGH THE EVENING.
IN ADDITION...FORECAST SOUNDINGS INDICATE FAVORABLE PROFILES FOR
GENERATION OF LAKE EFFECT CLOUDS WHICH ARE EXPECTED TO BE CARRIED ON
STRONG NORTHERLY FLOW INTO NEAR LAKE AREAS OF NORTHWEST
INDIANA...WHICH WILL LIMIT HIGHS THERE TO THE UPPER 60S. NORTHEAST
ILLINOIS MAY SEE A BIT OF A SHADOWING EFFECT TO KEEP CLOUD COVER AT
A MINIMUM FOR A TIME...BUT THE LAKESHORE WILL STILL STRUGGLE TO
REACH 70 DEGREES. ADDING TO THE FALL-LIKE FEEL WILL BE GUSTY
NORTH-NORTHEAST WINDS...STRONGEST NEAR THE LAKEFRONT...THANKS TO
A TIGHT PRESSURE GRADIENT AND THE UNSTABLE CONDITIONS OVER THE
LAKE. THOSE THAT BRAVE THE COOL CONDITIONS TO HEAD TO THE BEACH
WILL BE GREETED BY HIGH WAVES AND DANGEROUS CURRENTS...SO SWIMMING
IS STRONGLY DISCOURAGED.
TONIGHT...WINDS WILL QUICKLY DIMINISH AS THE HIGH BUILDS IN AND
SKIES SHOULD CLEAR FOR MOST AREAS AFTER ANY LINGERING EVENING
STRATOCU. THIS WILL SET THE STAGE FOR VERY CHILLY CONDITIONS IN
RURAL AND OUTLYING SUBURBAN AREAS WHERE UPPER 40S ARE EXPECTED AND
EVEN A FEW MID 40S ARE POSSIBLE. THE CHICAGO HEAT ISLAND WILL DROP
TO NEAR 60 DEGREES. THE EXCEPTION TO THE ABOVE WILL BE THE
NORTHWEST INDIANA AND POSSIBLY FAR EAST AND SOUTHEAST COOK COUNTY
LAKEFRONT...WHERE FAVORABLE LAKE EFFECT CONDITIONS WILL CONTINUE
TO EXIST AND RESULTANT CLOUD COVER WILL KEEP TEMPERATURES MILDER.
CONSIDERED PUTTING IN A SLIGHT CHANCE POP FOR LAKE EFFECT SHRA BUT
HELD OFF AND WILL ALLOW THE DAY SHIFT TO ASSESS...AS THE AIR MASS
MOVING OVER THE LAKE IS VERY DRY.
ON WEDNESDAY AND BEYOND...INVERSION LEVELS WILL DROP AS MID LEVEL
HEIGHTS RISE...SO ANY LAKE EFFECT CLOUDS WILL LIKELY DIMINISH
EARLY...BUT EXPECT TO SEE BLOSSOMING CUMULUS AGAIN BY LATE MORNING.
850 MB TEMPERATURES WILL BE CLOSE TO TODAY...BUT 925 MB TEMPS WILL
RISE TO SUPPORT A FEW DEGREE RISE IN HIGH TEMPERATURES. THE
CONTINUED GRADUAL DEPARTURE OF THE DEEP TROUGH OVER EASTERN CANADA
AND THE GREAT LAKES WILL RESULT IN WARMING THERMAL PROFILES ON
THURSDAY...SO AFTER ANOTHER CLEAR AND CHILLY NIGHT...SOME LOCATIONS
MAY TAG 80 DEGREES. THE SLOW WARMING TREND WILL THEN CONTINUE
THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH HIGHS IN THE MID 80S
OR EVEN WARMER POSSIBLY BY MONDAY. THE SOUTHEASTERN CWA COULD SEE
ENOUGH MOISTURE RETURN BEHIND HIGH PRESSURE FINALLY SHIFTING TO THE
EAST FOR A LIMITED THREAT FOR TSRA BY MONDAY OR POTENTIALLY AS EARLY
AS SUNDAY...BUT OTHERWISE THE DRY PATTERN MOST OF THE AREA HAS BEEN
IN SINCE THE BEGINNING OF JULY WILL CONTINUE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* STRONG/GUSTY NORTH/NORTHEAST WINDS THROUGH EARLY THIS EVENING.
* HIGH MVFR CIGS POSSIBLE THROUGH LATE MORNING/EARLY AFTERNOON.
CMS
//DISCUSSION...UPDATED 12Z...
TRICKY CLOUD AND WIND FORECAST FOR TERMINALS NEAR LAKE MICHIGAN
THIS MORNING. HIGH PRESSURE IS BUILDING IN FROM THE NORTH
PROVIDING COOLER AIR AND A NORTHERLY WIND FETCH DOWN LAKE
MICHIGAN. THIS HAS ALLOWED MVFR LAKE STRATUS TO DEVELOP AND REACH
THE ILLINOIS AND INDIANA SHORELINES. EXPECT THAT ORD/MDW WILL HAVE
A PERIOD OF SCT-BKN MVFR CLOUDS THIS MORNING BUT ITS NOT CLEAR HOW
LONG THEY WILL LINGER. GYY WILL LIKELY REMAIN BKN THROUGH THE
MORNING AND COULD DO SO THROUGH MUCH OF THE AFTERNOON AS WELL.
THE OTHER CHALLENGE WILL BE WINDS. LATEST SFC OBS AROUND THE LAKE
SUGGEST SOME CONVERGENCE IS SETTING UP ALONG THE WESTERN LAKESHORE
AS EVIDENCED BY SHORELINE WINDS TURNING NNW FROM THEIR EARLIER NE
DIRECTION. EXPECT THAT A SHIFT TO NNE OR NE WILL OCCUR YET THIS
MORNING BUT HAVE LOW CONFIDENCE IN HOW QUICKLY THIS WILL HAPPEN.
THIS MAY ALSO SERVE TO KEEP STRATUS IN PLACE AT ORD/MDW LONGER BUT
BASES WOULD LIKELY RISE TO LOWER END VFR LEVELS. OTHERWISE AREAS
AWAY FROM THE LAKE WILL BE MORE NORTHEASTERLY.
HIGH PRESSURE WILL BE JUST ABOUT OVER THE AREA THIS EVENING WHICH
WILL ALLOW WINDS TO DIMINISH. LAKE EFFECT PARAMETERS WILL STILL BE
FAVORABLE SO WILL NEED TO WATCH CLOUD TRENDS THROUGH THE AFTERNOON
BUT EXPECT GYY TO BE THE MAIN TERMINAL AFFECTED WITH LAKE CLOUDS
AS LOW/MID LEVEL WINDS WILL BE TURNING A BIT MORE NORTHWESTERLY
SUGGESTING ORD/MDW MAY REMAIN WEST OF THE CLOUDS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THROUGH THE PERIOD.
* MEDIUM FOR MVFR CIGS THIS MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH MONDAY...VFR.
MDB
&&
.MARINE...
300 AM CDT
A SERIES OF COLD FRONTS HAS NOW PUSHED SOUTH OF LAKE MICHIGAN WITH A
FAIRLY TIGHT PRESSURE GRADIENT POSITIONED ACROSS THE LAKE WITH LOW
PRESSURE TO THE EAST OVER EASTERN ONTARIO AND A STRONG HIGH PRESSURE
SYSTEM TO THE WEST FROM MANITOBA ACROSS THE DAKOTAS. NORTH TO
NORTHEAST WINDS HAVE INCREASED ACROSS THE LAKE AND WILL REMAIN
STRONG THROUGH LATE AFTERNOON AT WHICH POINT SPEEDS WILL BEGIN TO
GRADUALLY EASE AS THE PRESSURE GRADIENT SLACKENS. WESTERN AND
NORTHERN SECTIONS OF THE LAKE WILL SEE WINDS DIMINISHING FIRST AS
THE GRADIENT WILL BE WEAKENING FROM NORTHWEST TO SOUTHEAST. WAVES
WILL CONTINUE TO BUILD THIS MORNING WITH THE LONG FETCH DIRECTING
THEM AT THE SOUTHERN SHORELINES. HAVE BUMPED WAVES UP TO 5 TO 8 FT
WITH OCCASIONAL 12 FT FOR THE SOUTHERN PARTS OF THE LAKE WITH WELL
EXPOSED BUOYS NEAR THE END OF THE DEVELOPING FETCH ALREADY SHOWING
WAVES IN THE 4 TO 6 FT RANGE...WITH A FEW PEAKS CLOSER TO 7 FT. WILL
CONTINUE WITH THE SMALL CRAFT ADVISORY AS-IS. THE HIGH WILL MOVE
SOUTHWARD AND SETTLE INTO ILLINOIS INTO WEDNESDAY AND THEN GRADUALLY
SPREAD EASTWARD ACROSS THE OHIO VALLEY THROUGH THE END OF THE WEEK.
NORTHERLY WINDS WILL LIKELY TURN ONSHORE WEDNESDAY WITH THE WEAK
PRESSURE GRADIENT IN PLACE BEFORE SHIFTING TO SOUTHERLY ACROSS MOST
OF THE LAKE WEDNESDAY NIGHT AS THE HIGH SHIFTS. SOUTHWEST TO WEST
WINDS ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK BUT ONSHORE
FLOW WILL LIKELY SET UP ACROSS SOUTHERN PARTS OF THE LAKE WHERE THE
PRESSURE GRADIENT WILL REMAIN WEAK INTO THE WEEKEND.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 AM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
951 AM CDT Tue Aug 13 2013
.DISCUSSION...
ISSUED 950 AM CDT Tue Aug 13 2013
Large shield of cirrus clouds continues to push eastward this
morning, but has been showing some thinning as of late. Have had
quite a bit of stratus over the southeast CWA which is a bit
stubborn to erode, and a narrow band has also been quickly
dropping southwest toward the I-74 corridor as cooler and drier
air works its way toward our area. The diurnal cumulus should
start forming over the next couple hours, but latest CU-rule off
the RAP model diminishes this from north to south as the drier air
aloft mixes downward, so sunshine should be on the increase during
the afternoon.
Have made the usual minor hourly temperature adjustments for
today, which generally did not impact the high temperature
forecasts. Also refreshed the zone forecasts to remove mention of
morning fog in the eastern CWA, although little change was needed
otherwise.
Geelhart
&&
.AVIATION...
ISSUED 654 AM CDT Tue Aug 13 2013
IFR/MVFR fog will affect CMI through around 14z-15z, then dissipate
as dry air above the surface mixes down and surface dew point
spreads increase with daytime heating. High pressure will prevail
the remaining time of this TAF period, with VFR conditions. Light
north winds will become NNE and increase to 10-12kt by late
morning.
Diurnal clouds may thicken across our eastern areas, partially due
to some Lake Michigan moisture affects. Cu rule params show -1 to
-3 in that area as well, so we included a BKN040 cloud deck during
the day for CMI/BMI. There may be periods of SCT instead of BKN, but
we wanted to show the trend.
Shimon
&&
.PREV DISCUSSION...
ISSUED 253 AM CDT Tue Aug 13 2013
SHORT TERM...Today through Thursday
07z/2am surface analysis shows cold front settling southward
toward the Ohio River...with bulk of remaining convection now well
to the south across far southern Indiana into Kentucky. Despite
frontal passage and light northerly flow, air mass remains rather
humid across central Illinois. Surface dew points are still in the
middle to upper 60s across most of the area, with drier upper 50s
beginning to filter into the far north around Galesburg. Due to
mostly clear skies and light winds, this lingering low-level
moisture is producing some patchy fog around the area. Will
include fog mention in the forecast this morning, mainly for
locations south of I-72 where moisture will linger longest. After
any early morning fog dissipates, mostly sunny and cool weather
will be the rule today. Secondary cold front will allow very cool
air mass to pour southward into Illinois today, with 850mb temps
expected to drop into the 8 to 10C range. Numeric guidance is
suggesting highs only in the lower to middle 70s: however, based
on upstream readings yesterday afternoon and strength of mid-August
sun, think this is too cool. Will go several degrees above
guidance, with highs ranging from the middle 70s far north...to
the lower 80s along and south of I-70.
Clear skies and light winds will allow excellent radiational
cooling conditions to develop tonight, resulting in chilly
overnight lows in the upper 40s and lower 50s. With high pressure
remaining overhead, the cool/dry weather will continue on
Wednesday and Thursday as well, with highs in the middle to upper
70s and lows mainly in the 50s.
LONG TERM...Friday through Monday
Short-wave currently evident on water vapor imagery over Oregon
will track up and over the western CONUS ridge and into the
Midwest by the end of the week. This feature may trigger scattered
showers/thunder across Iowa and Nebraska Thursday night: however,
by the time it arrives in the drier air mass across Illinois, am
expecting only a slight increase in cloud cover on Friday. The
wave will act to amplify the existing long-wave trough in place
across the eastern CONUS this weekend into early next week. 00z
Aug 13 models continue to suggest the amplifying trough will
eventually lead to the development of an inverted surface trough
across the Ohio River Valley Sunday/Monday. This is the second
straight day models have latched onto this solution, so confidence
is growing that disturbed weather may develop to the E/SE early
next week. GFS/ECMWF spread a few showers into east-central/southeast
Illinois Sunday and Monday...however GEM tends to keep precip a
bit further east across Indiana. Will increase cloud cover and carry
a slight chance POP east of I-57 accordingly. Air mass will slowly
moderate through the period...with high temperatures climbing back
into the lower to middle 80s by Sunday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
739 AM CDT Tue Aug 13 2013
.UPDATE...
Issued at 724 AM CDT TUE AUG 13 2013
The thunderstorm complex over central Nebraska continues to build
toward the south southeast this morning. In the past hour, a
segment of this complex began to forward propagate with more of a
southeasterly direction. Instability is limited but does exist
along the highway 81 corridor, and recent RAP runs suggest that it
may increase to around 1000 J/Kg by mid morning. This would
suggest at least some potential for the system to maintain itself
into parts of north central Kansas. Have increased precip chances
to around 40 percent, but still see potential for the complex to
weaken, remain west of the forecast area, or even fall apart
before getting very far into Kansas. Will watch closely as it
evolves now that the sun has risen and instability may or may not
increase.
Barjenbruch
&&
.SHORT TERM...(Today and Tonight)
Issued at 324 AM CDT TUE AUG 13 2013
A ridge of surface high pressure had worked its way into northern
Kansas early this morning, bringing with it a rather stable
airmass. While yet another short wave trough was moving east across
southern Kansas this morning, thunderstorm activity has been confined
south of the forecast area. Between 2 and 4 AM, the thunderstorm
complex has attempted to make a run to the northeast as it pushed
out weak outflow, and has come close to Dickinson and Morris
counties, but the airmass just seems to increase in stability to the
north and the forecast area has remained dry thus far. Another short
wave trough of interest, well defined in water vapor imagery, was
diving south out of the Dakotas and has aided in development of a
thunderstorm complex over north central Nebraska.
This morning, there is still some small chance for the complex over
southern Kansas to send a few storms into the far southern parts of
the forecast area, and have maintained small chances for
thunderstorms in these areas accordingly. This potential may even
linger into the early afternoon hours as the center of the short
wave passes over eastern Kansas. The activity over Nebraska is
forecast to track generally to the south with the bulk of convection
favored on the western flank where it has greater instability to
work with. This should keep this system west of the forecast area,
but included a slight chance for precip generally near and west of
Highway 81 in case it should clip the area. Temperatures will be
similar to, or even a bit cooler than Monday with highs in the lower
80s. Kept the forecast for tonight dry as the surface high would
seem to maintain a hold on the area with a stable airmass, and the
stronger deep forcing and upper support looks to remain south and
west of the forecast area.
Barjenbruch
.LONG TERM...(Wednesday through Monday)
Issued at 324 AM CDT TUE AUG 13 2013
On Wednesday, expansive area of surface high pressure centered
over the Mississippi Valley begins to shift eastward leaving
another dry and pleasant day for the area. Edged high temperatures
during the afternoon into the lower 80s with weak low level winds
and peaks of sunshine expected by the late afternoon period.
Focus returns to the northwest flow aloft on Thursday as another
wave is progged to deepen as it enters the northern plains and dives
southeast. The recent runs of the NAM, GFS, and ECWMF have varying
timing and intensity differences with the GFS being the most
amplified of the group. Almost all solutions have agreed on slight
chances of sct thunderstorms developing ahead of the trough on
Thursday afternoon over north central KS. Otherwise was not
confident to increase rain chances Thursday evening as the main
piece of energy may center just north or east of the area. Continued
the trend from the afternoon package by assuming increasing cloud
cover could leave highs Thursday near the 80 degree mark. Depending
on timing with the main upper level system could still see some
lingering showers and thunderstorms Friday afternoon especially over
east central and northeast portions of KS. Models are beginning to
trend subsidence filling in behind the wave which would bring dry
conditions over north central areas. Will see if this trend
continues in upcoming days.
Looking at the extended period, the weekend continues to look dry
and pleasantly warm as the upper ridge builds into the plains
region. With the weak flow pattern in place, highs in the low 80s
and lows near 60 degrees still appear to be reasonable. Another
shortwave trough entering over the Pacific Northwest suppresses the
ridge as it shifts into the plains region as we head into Monday.
Continued with a dry forecast at this time as low confidence
exists in timing and how deep the wave is progged to be.
Temperatures will greatly depend on the scenario with highs at
this time trying to rise closer to normal values in the middle 80s
and lows in the 60s.
&&
.AVIATION...(For the 12Z TAFs through 12Z Wednesday Morning)
Issued at 621 AM CDT TUE AUG 13 2013
VFR conditions are forecast through the TAF period with light
northeast winds. The only uncertainty would be in some small
potential for vis restrictions after 06Z as shallow fog may
develop.
Barjenbruch
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Barjenbruch
LONG TERM...Bowen
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
600 AM CDT Tue Aug 13 2013
...Update to aviation for 12Z TAFs...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 420 AM CDT TUE AUG 13 2013
Wednesday:
A 70 kt 250 hPa jet streak will traverse across western Kansas through
the day. At the sfc, an upslope flow regime is expected with weak 850
hPa warm air advection/theta-e advection across far western Kansas.
For spatiotemporal adjustments of precipitation probability percentage
points, have relied heavily on ECMWF output solutions. Wednesday is
shaping up to be another MCS day. Orographic convection is expected
to form across the high plains and then drift southeast across the region
during the late evening and overnight period. The precipitation numerical
values are still in the chance category. The NAM solution is still dry
for the most part - but this model has failed with the MCS events recently,
so I remain dubious of any described solution herein. The tail end of
both WRF cores also support more confidence in the ECMWF solution. Heavy
rain will be possible again as precipitable water values are forecast
around the 75th percentile for a Gaussian distribution. Otherwise, maximums
will be cool because of all the cloud cover and lack of low level downslope
flow. Followed the ECE for guidance, which shows values in the upper
70sF to around 80F. Minimums into Thursday morning will be in the lower
60sF.
Thursday:
Another MCS day is possible Thursday. Upper level flow is more NW during
this period as a result the amplification of 500 hPa ridging across
the spine of the Rockies. This flow may advect any MCS activity farther
east than compared to the previous day. Heavy rain could be a possibility
again, as pwats continue on the higher end of the distribution spectrum.
Maximum surface temperatures could be a few degrees (F) warmer, particularly
across the western zones, as the 850 hPa warm plume advects slightly
farther east. A gradient of upper 80sF to around 80F is expected from
the west to the east with lows in the 60sF.
Friday and beyond:
Stuck with the weighted model solution (allblend) for the rest of the
forecast period as uncertainty continues to increase. There could be
some late afternoon and evening convection across the eastern zones
in association with an enhanced region of 850 hPa frontogenesis that
the ECMWF solutions shows on Friday. A drier forecast is possible next
weekend as the aforementioned 500 hPa ridge amplifies and expands farther
east across the region with a net result of drier northerly flow aloft
and higher mid level geopotential heights. Temperatures will moderate
to near normal during this drier period. Another period of convection
is possible in about a week from now as a trof moves across the northern
prairies. Will continue to tread lightly.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 600 AM CDT TUE AUG 13 2013
Afternoon and evening thunderstorms will be possible again today. Cigs
could be reduced in heavier thunderstorm activity, but this will be
very localized. Light and variable winds will become easterly 10 kt
by noon and continuing into this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 60 60 30 40
GCK 77 60 78 62 / 50 50 30 40
EHA 83 60 81 62 / 60 60 40 40
LBL 82 61 80 63 / 70 70 30 40
HYS 76 60 78 60 / 40 30 30 40
P28 78 62 81 64 / 70 70 20 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS JACKSON KY
1127 AM EDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 1127 AM EDT TUE AUG 13 2013
UPDATED THE TODAY PERIOD OF THE FORECAST AND THE HAZARDOUS WEATHER
OUTLOOK. UPDATED THE PRECIPITATION PROBABILITIES FOR THE REST OF
TODAY TO REFLECT THE LATEST TRENDS IN RADAR IMAGERY AND MOS GUIDANCE.
REMOVED MORNING AND AFTERNOON WORDING FROM THE ZONE TEXT PRODUCT AND
DECREASED PRECIPITATION CHANCES FOR THE REST OF THE DAY TO THE 30 TO
50 PERCENT CHANCE RANGE. ISOLATED TO SCATTERED SHOWERS AND STORMS ARE
EXPECTED TO MOVE ACROSS THE AREA TODAY AS A COLD FRONT MAKES ITS WAY
EAST. THIS ACTIVITY...AFTERNOON RAMPING UP A BIT LATE THIS
MORNING...IS EXPECTED TO GRADUALLY TAPER OFF DURING THE AFTERNOON AND
EARLY EVENING HOURS. ALSO REMOVED MENTION OF FLOODING AND HEAVY RAIN
FROM THE HAZARDOUS WEATHER OUTLOOK. IT APPEARS THAT THE THREAT FOR
HEAVY RAIN IS FINALLY OVER FOR EASTERN KENTUCKY.
UPDATE ISSUED AT 725 AM EDT TUE AUG 13 2013
UPDATED THE NEAR TERM GRIDS TO REFLECT THE BANDED SHOWERS CROSSING
THE SOUTHEAST PARTS OF THE CWA. ALSO ADJUSTED THE T/TD GRIDS THROUGH
THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBS AND TRENDS. THE REST
OF THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 725 AM EDT TUE AUG 13 2013
AVN CONDITIONS THROUGH EAST KENTUCKY WILL REMAIN RATHER POOR DURING
THE REST OF MORNING AS AREAS OF CONVECTION AND PATCHY FOG MOVE
THROUGH. HAVE LIMITED THE THUNDER AND VCTS CHANCES TO THE SOUTHERN
TAF SITES OF LOZ AND SME. ONCE THIS WAVE OF PCPN CLEARS...BY MID
MORNING...CONDITIONS WILL IMPROVE THROUGH THE DAY WITH JUST A SMALL
CHANCE OF A SHOWER OR THUNDERSTORM AND CIGS GENERALLY HOLDING IN THE
VFR RANGE. WILL FORECAST A TOUCH OF FOG DEVELOPING AT LOZ AND SME TAF
SITES TOWARD DAWN WEDNESDAY. WINDS THROUGH THE PERIOD WILL BE LIGHT
AND VARIABLE... OUTSIDE OF ANY STORM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
725 AM EDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 725 AM EDT TUE AUG 13 2013
UPDATED THE NEAR TERM GRIDS TO REFLECT THE BANDED SHOWERS CROSSING
THE SOUTHEAST PARTS OF THE CWA. ALSO ADJUSTED THE T/TD GRIDS THROUGH
THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBS AND TRENDS. THE REST
OF THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 725 AM EDT TUE AUG 13 2013
AVN CONDITIONS THROUGH EAST KENTUCKY WILL REMAIN RATHER POOR DURING
THE REST OF MORNING AS AREAS OF CONVECTION AND PATCHY FOG MOVE
THROUGH. HAVE LIMITED THE THUNDER AND VCTS CHANCES TO THE SOUTHERN
TAF SITES OF LOZ AND SME. ONCE THIS WAVE OF PCPN CLEARS...BY MID
MORNING...CONDITIONS WILL IMPROVE THROUGH THE DAY WITH JUST A SMALL
CHANCE OF A SHOWER OR THUNDERSTORM AND CIGS GENERALLY HOLDING IN THE
VFR RANGE. WILL FORECAST A TOUCH OF FOG DEVELOPING AT LOZ AND SME TAF
SITES TOWARD DAWN WEDNESDAY. WINDS THROUGH THE PERIOD WILL BE LIGHT
AND VARIABLE... OUTSIDE OF ANY STORM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
635 AM EDT Tue Aug 13 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 600 AM EDT Tue Aug 13 2013
This round of precip seems to be winding down, though these dry
periods have been very quick the past few days. Latest RAP indicates
some potential for another round somewhere over our western border
counties and of course in the still moisture rich environment across
the southeast. Brought back some slight chances to the west through
the morning then push the dry line south as the front gets through.
Speaking of the front, the first one to pass our area is hard to
define, except with a weak pressure trough running from near KCVG
and then through our northern counties. Second front now is over
northern Indiana, with dewpoints the easier find there, readings in
the 50s.
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Aug 13 2013
A couple of fronts are headed our way today. The first is slower
moving and stretches roughly from Lake Erie right to our northern
row of counties. The second has a more noticeable dewpoint
difference and is located between Central Michigan and southern
Wisconsin. Expect the first front to bring a wind shift into the
Ohio River area in the next few hours, but the main drier air with
the second front will not get here until this afternoon.
With a continued moist airmass in place ahead of the first front, we
are seeing lines of showers/embedded thunder continue to develop
early this morning. Will continue to watch for training of heavier
cells, but that watch should end soon, as that second front brings a
great rest of the work week forecast.
Highs today will depend on who can see the most sunshine. Most
places will stay cloudy, keeping readings around 80. The northern
forecast area has the best chance to break out behind the front, but
north winds should temper the extra sunshine and keep readings in
the lower 80s. Tonight, a steady north wind will keep us from ideal
radiational cooling, but lows should fall into the 50s for most
everyone. Then Wednesday under full sunshine and a north/northeast
wind highs look to rise only to the mid/upper 70s. Dewpoints may
drop into the mid 40s across the north, very low for mid August!
.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Tue Aug 13 2013
Upper air pattern will undergo a transition during the extended
period from troughing centered over the eastern Great Lakes (which
has been the prevailing pattern almost all summer) to a more typical
mid-summer pattern in which flat zonal flow retreats well north of
the Canadian border. However, this latter zonal flow won`t really
become established until Monday or Tuesday of next week.
A very dry and unseasonably cool airmass will already be in place
across the Great Lakes and the Lower Ohio Valley by Wednesday
evening. By late Wednesday, high pressure of Canadian origin is
forecast to lie near Chicago, with a ridge axis extending southeast
toward West Virginia. Clear skies and light winds will allow for
almost perfect radiational cooling early Thursday, and some
remarkably cool (for mid-August) overnight lows are expected for
early Thursday morning. Some lows may dip below 50 across some of
our typically colder rural locations!
Expect mostly clear skies with very comfortable temperatures and
humidities through Friday morning as high pressure settles overhead.
Highs both Thursday and Friday will hover not too far from 80. Lows
early Friday morning will reach the mid 50s.
For Saturday and Sunday, surface high pressure will move over New
England, with ridging extending southwest over the Ohio
River. Winds will stay quite light through the weekend, mostly from
an easterly direction. A weak upper level disturbance will slide
south across Missouri late Friday and will establish a weak 500mb
trough across southern Illinois, which will basically stay in
place through Sunday.
Isolated to scattered showers and thunderstorms are expected to our
east over the southern Appalachians on Friday, this convection may
re-develop a bit farther west Saturday and Sunday as light easterly
winds at the surface combine with relatively cool 500mb highs to
bring moderate afternoon and evening instability each day. This
convection will not be as widespread nor produce the heavy downpours
that some locations experienced over this past weekend. They will
also tend to develop during the afternoon and diminish during the
evening hours. Overall expect partly cloudy skies this weekend with
relatively cool highs in the lower to mid 80s with overnight lows in
the 60s. Think that each afternoon, scattered thunderstorm coverage
will be greatest across our southeastern counties and most sparse
across southern Indiana.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EDT Tue Aug 13 2013
Cold fronts still north of the terminals this morning. Thus
low-level moisture pooled ahead of them will keep lower ceilings in
at least for the next few hours. Expect the wind shift to come by
mid morning and help start to scour out these ceilings, in concert
with daytime heating. We may see a shower/storm at KBWG with the
passage around Noon, but then all sites should be VFR with stronger
north winds.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........RJS
Short Term.....RJS
Long Term......JSD
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
605 AM EDT Tue Aug 13 2013
...Forecast Update...
Issued at 600 AM EDT Tue Aug 13 2013
This round of precip seems to be winding down, though these dry
periods have been very quick the past few days. Latest RAP indicates
some potential for another round somewhere over our western border
counties and of course in the still moisture rich environment across
the southeast. Brought back some slight chances to the west through
the morning then push the dry line south as the front gets through.
Speaking of the front, the first one to pass our area is hard to
define, except with a weak pressure trough running from near KCVG
and then through our northern counties. Second front now is over
northern Indiana, with dewpoints the easier find there, readings in
the 50s.
.SHORT TERM (Now through Wednesday)...
Issued at 245 AM EDT Tue Aug 13 2013
A couple of fronts are headed our way today. The first is slower
moving and stretches roughly from Lake Erie right to our northern
row of counties. The second has a more noticeable dewpoint
difference and is located between Central Michigan and southern
Wisconsin. Expect the first front to bring a wind shift into the
Ohio River area in the next few hours, but the main drier air with
the second front will not get here until this afternoon.
With a continued moist airmass in place ahead of the first front, we
are seeing lines of showers/embedded thunder continue to develop
early this morning. Will continue to watch for training of heavier
cells, but that watch should end soon, as that second front brings a
great rest of the work week forecast.
Highs today will depend on who can see the most sunshine. Most
places will stay cloudy, keeping readings around 80. The northern
forecast area has the best chance to break out behind the front, but
north winds should temper the extra sunshine and keep readings in
the lower 80s. Tonight, a steady north wind will keep us from ideal
radiational cooling, but lows should fall into the 50s for most
everyone. Then Wednesday under full sunshine and a north/northeast
wind highs look to rise only to the mid/upper 70s. Dewpoints may
drop into the mid 40s across the north, very low for mid August!
.LONG TERM (Wednesday Night through Monday)...
Issued at 300 AM EDT Tue Aug 13 2013
Upper air pattern will undergo a transition during the extended
period from troughing centered over the eastern Great Lakes (which
has been the prevailing pattern almost all summer) to a more typical
mid-summer pattern in which flat zonal flow retreats well north of
the Canadian border. However, this latter zonal flow won`t really
become established until Monday or Tuesday of next week.
A very dry and unseasonably cool airmass will already be in place
across the Great Lakes and the Lower Ohio Valley by Wednesday
evening. By late Wednesday, high pressure of Canadian origin is
forecast to lie near Chicago, with a ridge axis extending southeast
toward West Virginia. Clear skies and light winds will allow for
almost perfect radiational cooling early Thursday, and some
remarkably cool (for mid-August) overnight lows are expected for
early Thursday morning. Some lows may dip below 50 across some of
our typically colder rural locations!
Expect mostly clear skies with very comfortable temperatures and
humidities through Friday morning as high pressure settles overhead.
Highs both Thursday and Friday will hover not too far from 80. Lows
early Friday morning will reach the mid 50s.
For Saturday and Sunday, surface high pressure will move over New
England, with ridging extending southwest over the Ohio
River. Winds will stay quite light through the weekend, mostly from
an easterly direction. A weak upper level disturbance will slide
south across Missouri late Friday and will establish a weak 500mb
trough across southern Illinois, which will basically stay in
place through Sunday.
Isolated to scattered showers and thunderstorms are expected to our
east over the southern Appalachians on Friday, this convection may
re-develop a bit farther west Saturday and Sunday as light easterly
winds at the surface combine with relatively cool 500mb highs to
bring moderate afternoon and evening instability each day. This
convection will not be as widespread nor produce the heavy downpours
that some locations experienced over this past weekend. They will
also tend to develop during the afternoon and diminish during the
evening hours. Overall expect partly cloudy skies this weekend with
relatively cool highs in the lower to mid 80s with overnight lows in
the 60s. Think that each afternoon, scattered thunderstorm coverage
will be greatest across our southeastern counties and most sparse
across southern Indiana.
&&
.AVIATION (06Z TAF Update)...
Issued at 1205 AM EDT Tue Aug 13 2013
Did an early round of updates to the TAFs as HRRR is indicating some
low cloud development in the wake of last night`s rains. KHNB is
coming in with these low clouds and think they will invade points
farther east as the night goes on. For now have gone with low-end
MVFR cigs, with worse conditions at KLEX by daybreak. Would not be
surprised to see some lower ceilings, but will introduce into the
TAFs for now and see how trends go the rest of the early morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........RJS
Short Term.....RJS
Long Term......JSD
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1034 AM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.UPDATE...
ISSUED AT 1034 AM EDT TUE AUG 13 2013
COLD ADVECTION STILL UNDERWAY ACROSS THE GREAT LAKES ON SOMEWHAT
GUSTY N/NW WINDS...AHEAD OF HIGH PRESSURE BUILDING INTO THE REGION
FROM SOUTH-CENTRAL CANADA. 12Z APX SOUNDING REVEALING AN 850 MB
TEMP OF +4C...RATHER COLD FOR THIS TIME OF YEAR AND FORECAST TO
BOTTOM OUT AROUND +3C TO +4C THIS AFTERNOON. PLENTY COLD ENOUGH
FOR LAKE CONVECTION...AND SURE ENOUGH...LOTS OF TRUE LAKE BANDS
HAVE DEVELOPED ON THE LAKES...PARTICULARLY ON LAKES MICHIGAN AND
HURON.
WITH HEATING...HYBRID LAKE AND LAND HEATING INDUCED STCU WILL
OVERSPREAD THE CWA AS WE GO THROUGH THE REST OF THE MORNING...A
PROCESS ALREADY UNDERWAY PER SATELLITE TRENDS IN THE LAST HOUR OR
SO. DEEP ENOUGH CONVECTION THAT A FEW SHOWERS APPEAR LIKELY THIS
AFTERNOON PARTICULARLY DOWNWIND OF THE LAKES WITH THE MOISTURE
FEED. IN FACT...APX RADAR ALREADY PICKING UP A FEW RETURNS OFF OF
GRAND TRAVERSE BAY. WILL MAKE SOME COSMETIC TWEAKS TO THE GRIDS
FOR SCATTERED SHOWERS AND HAVE INCREASED CLOUD COVER THROUGH THE
AFTERNOON. OTHERWISE...A DOWNRIGHT COOL DAY AHEAD WITH TEMPS A
SOLID 15 DEGREES BELOW NORMAL.
UPDATE ISSUED AT 657 AM EDT TUE AUG 13 2013
INCREASED WIND GUSTS IN A FEW SPOTS...MAINLY OVER THE GREAT
LAKES...PER LATEST OBS AND INCREASING INSTABILITY. LOW LEVEL
MOISTURE EXPECTED TO DEVELOP INTO A PERIOD OF MOSTLY CLOUDY
SKIES...OF WHICH DID MAKE A CHANGE TO EXTEND THIS CLOUDIEST TIME
PERIOD. OTHERWISE...FORECAST LOOKING GOOD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 657 AM EDT TUE AUG 13 2013
COLD ADVECTION BEHIND COLD FRONT LAST NIGHT HAS RESULTED IN
POCKETS OF MVFR CIGS. THIS SHOULD BE MORE PREVALENT OVER THE NEXT
FEW HOURS WITH SUNUP AND FCST SOUNDINGS SHOWING POTENTIAL TRAPPING
INVERSION. ONGOING TAFS ARE REALLY HARD TO ARGUE...AS THINGS ARE
QUITE TEMPORARY RIGHT NOW ON THE MVFR FRONT. MORE PREVAILING
THROUGH EARLY AFTERNOON...WHICH IS WHAT THE TAFS PORTRAY. DRYING
THROUGH THE DAY AND LOSS OF SUN WILL LEAD TO PREVAILING VFR
CONDITIONS...ALTHOUGH MOISTURE AND INSTABILITY OFF THE LAKE MAY
TRY AND KEEP CLOUDS IN LONGER/REDEVELOP...ESPECIALLY OVERNIGHT.
GUSTY TODAY ALL AREAS...ESPECIALLY ALONG THE LAKESHORES. GUSTS UP
TO 25 KNOTS OUT OF THE NW.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...BA
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
737 AM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT TUE AUG 13 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
QUEBEC INTO NRN ONTARIO RESULTING IN CYCLONIC WNW FLOW THROUGH THE
NRN GREAT LAKES. LITTLE MORE THAN PATCHY MID CLOUDS WERE ASSOCIATED
WITH A SHORTWAVE TROUGH MOVING THROUGH WRN LAKE SUPERIOR WHILE MORE
EXTENSIVE CLOUDS AND A FEW SPRINKLES WERE OBSERVED WITH ANOTHER
SHRTWV JUST UPSTREAM...TO THE N OF LAKE SUPERIOR. AT THE SFC...HIGH
PRES OVER MANITOBA INTO NW MN WAS BUILDING INTO THE WRN LAKES WITH
NRLY FLOW PREVAILING ACROSS LAKE SUPERIOR INTO UPPER MICHIGAN.
TODAY...AS THE SHRTWV FROM N OF THE LAKE AND A POCKET OF LOWER 700 MB
TEMPS AROUND -6C...DROPS THROUGH THE CWA...MODELS SUGGEST THAT SOME
ISOLD SHOWERS WILL BE POSSIBLE FROM LATE THIS MORNING INTO THE EARLY
AFTERNOON...MAINLY THROUGH W CNTRL UPPER MI. IN ITS WAKE...SUBSIDENCE
AND DRYING WILL BUILD QUICKLY INTO THE AREA...ENDING ANY PCPN BY MID
TO LATE AFTERNOON.
TONIGHT...WITH CLEARING SKIES AND LIGHT WINDS AS THE HIGH BUILD INTO
THE REGION...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY
AIRMASS(PWAT TO AROUND 0.50 INCH OR 50 PCT OR NORMAL) WILL ALLOW
TEMPERATURES TO DROP TOWARD THE LOWER END OF GUIDANCE....INTO THE
MID TO UPPER 30S INLAND WEST. THE TYPICAL COLDER LOCATIONS FROM
CHAMPION AND AMASA TO WATERSMEET...KENTON AND WATERSMEET COULD SEE
SOME PATCHY FROST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 432 AM EDT TUE AUG 13 2013
THE VERY COOL MORNING TEMPS WILL QUICKLY RISE INTO THE UPPER 60S TO
MID 70S WEDNESDAY AS THE SFC HIGH OVERHEAD CONTINUES TO SLOWLY SINK
TO OUR SSE. A SLOW WARMING TREND WILL BEGIN WEDNESDAY NIGHT...WITH
THE SFC HIGH LINGERING ACROSS THE OHIO VALLEY AND NEW ENGLAND STATES
THROUGH AT LEAST THE START OF THE NEXT WORK WEEK.
THURSDAY WILL SEE A RETURN OF NEAR NORMAL HIGH TEMPS...IN THE
70S...AS 850MB TEMPS FINALLY RISE INTO THE DOUBLE DIGITS AND...STAY
THERE FOR THE REMAINDER OF THE FCST PERIOD.
THERE WILL BE ONLY FEW SYSTEMS OF NOTE OVER THE WEEK...WITH NW FLOW
ALOFT REMAINING IN PLACE THROUGH THE END OF THE WORK WEEK. THE MAIN
500MB LOW WILL BE SPINNING AROUND AND NEAR QUEBEC THROUGH THURSDAY
BEFORE EJECTING NE IN THE MAIN FLOW AROUND THE STRONGER POLAR LOW. A
SERIES OF SHORTWAVES WILL ATTEMPT TO ROUND THE HIGH AMPLITUDE RIDGE
OVER MUCH OF THE WESTERN STATES EARLY TO MID WEEK...
SEEING A SFC LOW TRACKING FROM S ALBERT AND SASKATCHEWAN ON FRIDAY
TO S CENTRAL CANADA OVER THE WEEKEND. THE 12/12Z ECMWF IS MUCH
QUICKER TO PUSH THE SFC LOW ACROSS HUDSON BAY OVER THE WEEKEND.
THERE ARE SIGNIFICANT ENOUGH TIMING DIFFERENCES BETWEEN THE
AVAILABLE GUIDANCE TO KEEP ONLY LIGHT CHANCE POPS IN THE FCST AS
WARM BUT MAINLY DRY AIR PUSHES IN ON SW WINDS AT THE SFC SATURDAY
THROUGH THE END OF THIS FCST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 736 AM EDT TUE AUG 13 2013
MORE INSTABILITY CU/SC WILL DEVELOP THIS MORNING WITH THE ONSET OF
DAYTIME HEATING AND THE APPROACH OF ANOTHER DISTURBANCE...BUT
CONDITIONS ARE LIKELY TO BE VFR. THE BEST CHANCE FOR SOME MVFR CIGS
LATER THIS MORNING INTO THE AFTERNOON WILL BE AT SAW WITH MORE
FAVORABLE UPSLOPE AND GUSTY N WIND.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT TUE AUG 13 2013
NRLY WINDS OF 15 TO 20 KNOTS OVER THE ERN PORTIONF OF LAKE SUPERIOR
WILL DIMINISH TONIGHT AS HIGH PRES BUILDS INTO THE REGION. AS THE
HIGH SINKS TO THE SOUTH WED INTO WED NIGHT WRLY WINDS OF 15 TO 20
KNOTS ARE ALSO EXPECTED OVER CNTRL AND ERN LAKE SUPERIOR.
OTHERWISE...WINDS AOB 15 KNOTS WILL PREVAIL INTO SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
705 AM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.UPDATE...
ISSUED AT 657 AM EDT TUE AUG 13 2013
INCREASED WIND GUSTS IN A FEW SPOTS...MAINLY OVER THE GREAT
LAKES...PER LATEST OBS AND INCREASING INSTABILITY. LOW LEVEL
MOISTURE EXPECTED TO DEVELOP INTO A PERIOD OF MOSTLY CLOUDY
SKIES...OF WHICH DID MAKE A CHANGE TO EXTEND THIS CLOUDIEST TIME
PERIOD. OTHERWISE...FORECAST LOOKING GOOD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 657 AM EDT TUE AUG 13 2013
COLD ADVECTION BEHIND COLD FRONT LAST NIGHT HAS RESULTED IN
POCKETS OF MVFR CIGS. THIS SHOULD BE MORE PREVALENT OVER THE NEXT
FEW HOURS WITH SUNUP AND FCST SOUNDINGS SHOWING POTENTIAL TRAPPING
INVERSION. ONGOING TAFS ARE REALLY HARD TO ARGUE...AS THINGS ARE
QUITE TEMPORARY RIGHT NOW ON THE MVFR FRONT. MORE PREVAILING
THROUGH EARLY AFTERNOON...WHICH IS WHAT THE TAFS PORTRAY. DRYING
THROUGH THE DAY AND LOSS OF SUN WILL LEAD TO PREVAILING VFR
CONDITIONS...ALTHOUGH MOISTURE AND INSTABILITY OFF THE LAKE MAY
TRY AND KEEP CLOUDS IN LONGER/REDEVELOP...ESPECIALLY OVERNIGHT.
GUSTY TODAY ALL AREAS...ESPECIALLY ALONG THE LAKESHORES. GUSTS UP
TO 25 KNOTS OUT OF THE NW.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...SD
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS GLASGOW MT
918 AM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
BEST INSTABILITY LATER TODAY SHOULD BE OCCURRING OVER THE EASTERN
ZONES WHERE SURFACE BOUNDARY IS LOCATED. LEANED ON RUC AND HRRR WITH
THE UPDATE AS THEY HAVE ACTIVITY IN THIS AREA. QUITE A BIT OF
MOISTURE IN THE COLUMN THIS MORNING WITH 1.18" PRECIPITAL WATER...SO
HEAVY RAIN WILL BE POSSIBLE WITH SLOW MOVING STORMS. REST OF
FORECAST LOOKED GOOD. TFJ
PREVIOUS DISCUSSION...
A SLOW MOVING FRONTAL BOUNDARY WILL COMBINE WITH SHORTWAVES
OVERTOPPING AN UPPER RIDGE AND MOIST UNSTABLE AIRMASS TO PRODUCE
THUNDERSTORMS AT TIMES TODAY THROUGH WEDNESDAY NIGHT. WITH
PRECIPITABLE WATER EXPECTED TO BE BETWEEN AN INCH AND 1.25
INCHES... LOCALLY HEAVY RAIN IS ALSO POSSIBLE WHICH MAY PRODUCE
FLASH FLOODING. MODELS DIFFER IN WHEN AND WHERE IT WILL RAIN WITH
THE INDIVIDUAL WAVES. WILL BROADBRUSH ISOLATED TO SCATTERED
THUNDERSTORMS TODAY AND TONIGHT WITH HEAVY RAIN POSSIBLE FOLLOWED
BY ISOLATED TO SCATTERED THUNDERSTORMS ON WEDNESDAY AND A CHANCE
OF THUNDERSTORMS WEDNESDAY NIGHT.
UPPER RIDGE STRENGTHENS OVER THE FORECAST AREA ON THURSDAY WITH
SOMEWHAT DRIER... WARMER AND MORE STABLE AIRMASS WHICH WILL LIMIT THE
CHANCES OF THUNDERSTORMS. WITH SHORTWAVE LACKING IN THE FLOW
ALOFT... WILL GO WITH A DRY FORECAST FOR NOW. FORRESTER
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. MVFR POSSIBLE WITH THUNDER OR HAZE.
THUNDER: THE EDGE OF A RIDGE WILL PROVIDE ENOUGH LIFT FOR SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP NEAR THE KOLF... KSDY... AND KGDV
TERMINALS THIS AFTERNOON... HOWEVER CHANCES ARE NOT HIGH ENOUGH TO
PLACE DIRECTLY IN THE TAFS. THEREFORE WILL GO WITH CB/S UNTIL KICK
OFF TIME AROUND 18 TO 21Z AND AMEND AS NEEDED. AS USUAL... BRIEF
VISIBILITY OBSCURATION AND SUDDEN GUSTY WINDS ARE POSSIBLE NEAR
ANY THUNDERSTORM.
HAZE: HAZE FROM FIRES TO THE WEST HAS REDUCED VISIBILITY TO WELL
LESS THAN 20 MILES AT TIMES AND ACCORDING TO PREVIOUS OBSERVATIONS
ON RARE OCCASIONS CAN REACH THE MVFR OBSCURATION OF 5 MILES.
HOWEVER... THIS IS FAR TOO RARE TO PLACE IN THE TAFS DIRECTLY.
WILL AMEND IF BECOMES NECESSARY.
AREA WINDS: WINDS WILL BE OUT OF THE SOUTH AND EAST AROUND 10 KTS
SUSTAINED... GUSTING UP TO 15 KTS DURING THE AFTERNOON.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORMAN OK
628 AM CDT TUE AUG 13 2013
.DISCUSSION...
PLEASE SEE THE 12Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
A LINE OF SHOWERS AND THUNDERSTORMS WILL SLOWLY CONTINUE TO DRIFT
SOUTHWARD THROUGHOUT THE DAY. EXPECT AT LEAST MVFR TO APPLY OVER
MOST TERMINALS UNTIL PERHAPS LATER THIS AFTERNOON AND THIS
EVENING. GAG AND WWR WILL HAVE THE BEST FLIGHT CONDITIONS THROUGH
TODAY WITH ONLY BRIEF MVFR A POSSIBILITY EARLY THIS MORNING.
HOWEVER...THERE WILL STILL BE A CHANCE FOR TSRA THERE LATER THIS
AFTERNOON. CONFIDENCE IS NOT VERY HIGH REGARDING THE PREVIOUS
THOUGH SO WILL ONLY INCLUDE PROB30S FOR NOW. MVFR TO IFR CIGS ARE
EXPECTED FROM AROUND 09-12Z TOMORROW BEHIND THIS COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE AUG 13 2013/
DISCUSSION...
MOIST CONVECTION HAS INCREASED ALONG THE 925 MB BAROCLINIC ZONE
EARLY THIS MORNING. THE NAM12 AND RUC13 ARE DEPICTING THIS VERY
WELL...AND INDICATE THE BEST WAA WILL OCCUR BETWEEN NOW THROUGH
ABOUT 12Z BEFORE THE FRONT BEGINS TO NUDGE SOUTHWARD. SLOW MOVING
STORMS ALONG THIS ZONE...TRAINING...AND VERY HIGH PWATS (OUN 00Z
1.92 IN) WILL SUPPORT HIGH RAINFALL RATES THROUGH EARLY THIS
MORNING. BY THIS AFTERNOON AND EVENING...A SHORTWAVE TROUGH MOVING
OUT OF KS WILL MOST LIKELY RESULT IN REDEVELOPMENT ACROSS MUCH
OF THE AREA. THE HEAVIEST RAIN IS EXPECTED ACROSS PORTIONS OF
SOUTHERN OK THIS AFTERNOON AND EVENING...AND PERHAPS EVEN W N TX
NEAR THE BOUNDARY LATE TONIGHT. THEREFORE...WILL EXTEND FFA
SOUTHWARD TO INCLUDE SOUTHERN PORTIONS OF OK WHERE SOME LOCALIZED
HEAVY RAINFALL ALREADY OCCURRED YESTERDAY. RAIN CHANCES WILL SHIFT
SOUTHWARD WITH THE BOUNDARY LATE TONIGHT THROUGH EARLY WED
MORNING. WILL KEEP MAX TEMPS CLOSE TO THE MET GUIDANCE FOR TODAY
CONSIDERING PERSISTENT STRATUS AND PRECIP CHCS THROUGH THE DAY.
SOME PARTS OF THE OKC METRO MAY NOT MAKE IT OUT OF THE 70S.
A SFC RIDGE WILL EXTEND THROUGH THE FA FROM THE NE WED BEHIND THE
FRONT KEEPING TEMPS WELL BELOW NORMAL. NORTHERLY FLOW ALOFT WILL
CONTINUE OVERHEAD THROUGH THE WORK WEEK...WITH THE POSSIBILITY OF
ADDITIONAL SUBTLE SHORTWAVE TROUGHS MOVING OVER THE PLAINS. POPS
WILL INCREASE AGAIN ON THURSDAY AS ONE SUCH WAVE TRAVERSES THE
REGION. AN EVEN MORE SIGNFICANT MID TO UPPER SHORTWAVE TROUGH IS
ANTICIPATED BY FRIDAY SO DECIDED TO INCREASE POPS TO AT LEAST CHC.
OVERALL...EXPECT AN UNUSUALLY COOL AND MOIST FORECAST THROUGH THE
ENTIRE FORECAST PERIOD AS NORTHERLY MID LEVEL FLOW REMAINS IN
PLACE WITH THE UPPER RIDGE AXIS WEST OF THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 81 69 83 67 / 80 40 20 10
HOBART OK 84 69 86 68 / 70 40 30 10
WICHITA FALLS TX 96 73 89 70 / 50 60 40 20
GAGE OK 80 65 82 64 / 60 40 20 20
PONCA CITY OK 82 66 82 64 / 50 40 20 10
DURANT OK 90 73 87 67 / 70 60 50 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OKZ004>032-040>043-
047-048.
TX...NONE.
&&
$$
02/03/03
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
754 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL PASS ACROSS THE REGION TODAY. THEN A LARGE HIGH
PRESSURE SYSTEM WILL BUILD IN OVER THE OHIO VALLEY AND THE MID
ATLANTIC TONIGHT AND WEDNESDAY...BRINGING SOMEWHAT COOLER AND
DRIER WEATHER. THIS WILL LAST LATE INTO THE WEEK BEFORE MOISTURE
STARTS TO SLOWLY RETURN BY THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 658 AM EDT TUESDAY...
UPDATED POPS/WEATHER AND RAINFALL FOR NEXT FEW HOURS PER
CONCENTRATED AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDER
ACROSS MT ROGERS REC AREA AND FAR NW NC. LATEST HRRR HAS
REASONABLE HANDLE ON THIS AND TAKES IT ALL THE WAY INTO PIEDMONT
THROUGH 13Z. THINK THIS MAY BE A LITTLE FAST AND MAY NOT SURVIVE
FULLY INTACT THAT FAR EAST...BUT DID INCREASE POPS OUT OF AHEAD OF
IT AND BROUGHT LIKELY INTO FOOTHILLS AND TOWARD LYH A LITTLE
EARLIER. WILL NEED CONSTANT TWEAKING. RAINFALL RATES ARE FROM 2-3
INCHES PER HOUR IN STRONGER RETURNS...BUT IT IS MOVING AT ABOUT 40
MPH. ANOTHER WAVE OF ACTIVITY WILL ENTER FROM EASTERN KY THOUGH BY
800 AM...SO MANY AREAS WILL NEED TO BE WATCHED CAREFULLY FOR FLASH
FLOOD POTENTIAL THROUGH AT LEAST THE MORNING HOURS.
PREV DISCUSSION AS OF 440 AM EDT TUESDAY...
SURFACE COOL FRONT CONTINUES TO SLOWLY MAKE ITS WAY SOUTHEASTWARD
THROUGH THE OHIO VALLEY EARLY THIS MORNING WITH WAVES RIPPLING
ALONG IT IN THE UPPER LEVELS. THIS IS RESULTING IN CONTINUED AREAS
OF ORGANIZED BUT FAIRLY SHALLOW CONVECTION FROM UPSTATE NY AND
PA...SOUTHWESTWARD ALONG THE WEST SIDE OF THE APPALACHIANS AND
INTO CENTRAL KY. AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS HAVE
GENERALLY BEEN WEAKENING AS THEY MOVE INTO THE WESTERN PORTIONS OF
OUR FCST AREA WITH WEST FLOW AND LITTLE TO NO INSTABILITY
REMAINING. ONE WAVE MAY BRING A MORE ORGANIZED AREA INTO THE WEST
DURING THE FRIST PART OF THE DAYLIGHT HOURS JUST AHEAD OF FRONTAL
BOUNDARY. FRONT WILL THEN PUSH ACROSS DURING THE DAY...BUT AS
USUAL NOT CLEANLY...WITH SOME LEE SIDE TROUGHING ALREADY EVIDENT
THIS MORNING...IT MAY SHIFT INTO THE PIEDMONT THIS
AFTERNOON...WITH DEEPER CONVECTION FIRING ACROSS THE EASTERN
PORTIONS OF OUR AREA OR MAYBE EVEN OFF TO THE EAST BY MID TO LATE
AFTERNOON. WITH TIMING OF POPS...GENERALLY FOLLOWED A BLEND OF THE
06Z RAP13 AND HIGH RES WRF-ARW FROM 00Z.
DO NOT THINK THERE WILL BE MANY BREAKS IN CLOUD COVER SO
INSTABILITY REMAINS WEAK TO MODEST...MAYBE 1000-1500 SFC BASED
MOST AREAS...WITH UP TO 2000 J/KG IN THE EAST IF WE CAN GET A FEW
BREAKS IN CLOUDS. DO NOT SEE MUCH IN THE WAY OF SEVERE WEATHER
POTENTIAL GIVEN VERY MOIST AIRMASS AND NOT ESPECIALLY STEEP LAPSE
RATES. LOCALLY HEAVY RAIN WILL BE MAIN CONCERN AGAIN...AND GIVEN
RAINFALL LAST EVENING AND SOME CONTINUED LIGHT TO MODERATE
OVERNIGHT IN FAR WEST...BIGGEST THREAT FOR ANY FLASH FLOODING
REMAINS IN THE WEST...EVEN THOUGH THERE IS SOME QUESTION AS TO
WHETHER ANY DEEPER CONVECTION CAN SUSTAIN ITSELF OR GET GOING
DURING THE MORNING HOURS BEFORE THE FRONT PUSHES THROUGH THE
MOUNTAINS. WILL KEEP THE FLASH FLOOD WATCH GOING THROUGH THE
DAY...ALTHOUGH AREAS IN THE FOOTHILLS VERY MARGINAL...AND WE WILL
LIKELY BE ABLE TO CANCEL EARLY AS BELIEVE ANY ORGANIZED CONVECTION
AND HEAVIER RAINFALL RATES WILL SHIFT EAST BY EARLY TO MID
AFTERNOON.
FRONT PUSHES WELL EAST BY EARLY EVENING IF NOT SOONER..QUICKLY
LOWERING THREAT OF SHWRS/STORMS ACROSS THE ENTIRE AREA BEFORE
MIDNIGHT. KEPT CHC POP GOING IN EAST UNTIL MIDNIGHT...BUT MY
FEELING IS THIS MAY MOVE OUT EVEN QUICKER. ALSO THERE IS LINGERING
LOW LEVEL MOISTURE ON WEST SLOPES BEHIND FRONT AND MAYBE SOME
SPRINKLES OR DRIZZLE IS POSSIBLE FOR A WHILE THIS EVENING BACK
THERE AS WELL...SO KEPT LOW CHC POPS INTO EARLY EVENING AS WELL.
TEMPERATURE WISE...AM LEANING TO COOLER MET GUIDANCE FOR HIGHS GIVEN
EXPECTED CLOUD COVER...AND EVEN NUDGED DOWN A DEG OR TWO FROM
THERE. ONE AREA THAT MAY END SEEING A LITTLE MORE SUN IS FAR
SOUTHEAST AND IF THERE ARE MORE THAN JUST A COUPLE HOURS OF IT
DURING TEH AFTERNOON THE LOW 90S TEMPS THE MAV IS ADVERTISING
COULD BE REALIZED...SO WILL HAVE TO WATCH THIS. TONIGHT WE MAY SEE
THE FIRST 50S IN THE WEST IN QUITE SOME TIME WITH LOWER DEW PTS
MOVING IN AND SOME CLEARING.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
LOOKING AT MAINLY DRY CONDITIONS FOR WEDNESDAY...POSSIBLY WITH A FEW
LINGERING SHOWERS ACROSS OUR NORTHWEST WIND UPSLOPE AREAS DURING THE
MORNING...AS CANADIAN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
UPPER MIDWEST. THIS AIRMASS WILL BRING A SIGNIFICANT COOL DOWN TO OUR
AREA...WITH AFTERNOON HIGHS RANGING FROM 7 TO 9 DEGREES BELOW NORMAL
FOR MID AUGUST. HIGH PRESSURE WILL SHIFT EAST DURING THE DAY...AND
THEN BUILD SOUTHWARD ALONG THE EASTERN FACE OF THE APPALACHIANS
WEDNESDAY NIGHT...WHICH WILL SHIFT OUR WINDS TO A NORTHEASTERLY
DIRECTION.
THURSDAY WILL REMAIN RELATIVELY DRY AS WELL...ALTHOUGH MAY SEE A
LITTLE LIGHT RAIN ENTER THE NORTH CAROLINA MOUNTAINS AND THE
MOUNTAIN EMPIRE ON THURSDAY AS WINDS AROUND THE HIGH PRESSURE WEDGE
PICK UP MOISTURE FROM UPPER LEVEL DISTURBANCES RIDING ALONG THE COLD
FRONT STALLED WELL TO OUR SOUTH. RAINFALL WILL REMAIN ISOLATED
HOWEVER...AND WOULD NOT MAKE ANY CHANGES TO OUTDOOR PLANS AT THIS
POINT. THE COOL EASTERLY FLOW WILL AGAIN KEEP TEMPERATURES SEVERAL
DEGREES BELOW NORMAL...WITH MOST AREAS HOLDING IN THE 70S FOR
AFTERNOON HIGHS.
WILL SEE A BETTER RETURN OF MOISTURE FOR FRIDAY AS A DEEP UPPER
LEVEL TROUGH MOVES INTO THE CENTRAL MISSISSIPPI RIVER VALLEY. WHILE
HIGH PRESSURE WILL REMAIN IN PLACE IN THE LOW LEVELS...WINDS ALOFT
ALONG THE EASTERN SEABOARD WILL BECOME INCREASINGLY SOUTHWESTERLY AS
THE TROUGH AMPLIFIES. THIS UPPER FLOW WOULD BE FAVORABLE FOR
CARRYING DISTURBANCES ACROSS THE CAROLINAS...WHICH WOULD POTENTIALLY
TRIGGER SPOTTY SHOWERS AND THUNDERSTORMS FOR OUR AREA SOUTH OF
INTERSTATE 81.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...
AS WE PROGRESS INTO THE WEEKEND...CURRENT MODEL TRENDS OFFER A
STALLED DEEPENING LOW OVER THE CENTRAL U.S. WITH THE LOW ALONG THE
GULF BEING TRANSPORTED NORTHWARD ON THE EAST SIDE OF THE CENTRAL
CONUS TROUGH. THIS WOULD ALLOW FOR BETTER DYNAMICS AND MOISTURE FLOW
ACROSS THE REGION. THIS WILL LEAD TO BETTER CHANCE OF LIGHT TO
MODERATE RAIN OVER THE AREA THROUGH SATURDAY...AND THEN BETTER
CHANCES OF SHOWERS AND SOME THUNDERSTORMS BY SUNDAY. WHILE ACTIVITY
MAY TAPER OFF A BIT ON MONDAY...THE CENTRAL CONUS TROUGH WOULD STILL
BE TO OUR WEST...AND BE A FEATURE TO POTENTIALLY INFLUENCE OUR
WEATHER PAST DAY 7.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 750 AM EDT TUESDAY...
PERIODS OF IFR IN HEAVY SHOWERS AND ISOLATED THUNDERSTORMS THIS
MORNING ACROSS THE WEST...WILL GIVE WAY TO MAINLY VFR CONDITIONS
BY AFTERNOON BUT STILL WITH SCATTERED SHOWERS AND STORMS AND BRIEF
MVFR TO IFR CONDITIONS WITH STORMS AS A COLD FRONT PUSHES THROUGH
THE REGION THROUGH THE MIDDLE OF THE DAY TODAY...EXITING THE FAR
SOUTHEAST BY EARLY EVENING. SOME PATCHY FOG AT DAN AND LYH THIS
MORNING SHOULD ALSO IMPROVE TO VFR BY MID MORNING...YET STILL WITH
BRIEF IFR CONDITIONS POSSIBLE IF A THUNDERSTORM MOVES ACROSS THE
AIRPORT. KEPT THUNDER MENTIONED IN VICINITY SINCE NOT CONFIDENT IN
HOW WIDESPREAD COVERAGE WILL BE OUT EAST.
BY LATE TODAY THE FRONT WILL SHIFT SLOWLY SOUTHEAST AND TURN THE
WINDS TO THE WNW BY AFTERNOON. BY EARLY EVENING...DRIER AIR WILL
BE FILTERING IN AND LINGERING SHOWERS WILL PUSH EAST OF
DAN/LYH...BY 02Z OR EARLIER. SOME LINGERING LOW LEVEL MOISTURE IN
TEH FAR WEST COULD RESULT KIN IFR CIGS OVERNIGHT...AS WELL AS
PATCHY IFR FOG AT VALLEY AIRPORTS...BUT BY WED VFR SHOULD DOMINATE
THROUGH MOST OF THE REST OF WEEK UNDER DRY HIGHI PRESSURE.
&&
.HYDROLOGY...
AS OF 355 PM EDT MONDAY...
NO CHANGES TO FLASH FLOOD WATCH. SOME AREAS RECEIVED 3"+ OVER THE
MOUNTAIN EMPIRE OF SW VA...INCLUDING THE RICHLANDS AREA LAST
EVENING.
MORE HEAVIER DOWNPOURS ARE POSSIBLE AGAIN TODAY...MAINLY IN THE
MORNING WEST AND AFTERNOON EAST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VAZ007-009>017-032.
NC...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NCZ001>003-018-019.
WV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WVZ042>045.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...NF
LONG TERM...DS/NF
AVIATION...SK/WP
HYDROLOGY...AMS/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
700 AM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL PASS ACROSS THE REGION ON TODAY. THEN A LARGE
HIGH PRESSURE SYSTEM WILL BUILD IN OVER THE OHIO VALLEY AND THE
MID ATLANTIC TONIGHT AND WEDNESDAY...BRINGING SOMEWHAT COOLER AND
DRIER WEATHER. THIS WILL LAST LATE INTO THE WEEK BEFORE MOISTURE
STARTS TO SLOWLY RETURN BY THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 658 AM EDT TUESDAY...
UPDATED POPS/WEATHER AND RAINFALL FOR NEXT FEW HOURS PER
CONCENTRATED AREA OF HEAVY RAIN SHOWERS AND ISOLATED THUNDER
ACROSS MT ROGERS REC AREA AND FAR NW NC. LATEST HRRR HAS
REASONABLE HANDLE ON THIS AND TAKES IT ALL THE WAY INTO PIEDMONT
THROUGH 13Z. THINK THIS MAY BE A LITTLE FAST AND MAY NOT SURVIVE
FULLY INTACT THAT FAR EAST...BUT DID INCREASE POPS OUT OF AHEAD OF
IT AND BROUGHT LIKELY INTO FOOTHILLS AND TOWARD LYH A LITTLE
EARLIER. WILL NEED CONSTANT TWEAKING. RAINFALL RATES ARE FROM 2-3
INCHES PER HOUR IN STRONGER RETURNS...BUT IT IS MOVING AT ABOUT 40
MPH. ANOTHER WAVE OF ACTIVITY WILL ENTER FROM EASTERN KY THOUGH BY
800 AM...SO MANY AREAS WILL NEED TO BE WATCHED CAREFULLY FOR FLASH
FLOOD POTENTIAL THROUGH AT LEAST THE MORNING HOURS.
PREV DISCUSSION AS OF 440 AM EDT TUESDAY...
SURFACE COOL FRONT CONTINUES TO SLOWLY MAKE ITS WAY SOUTHEASTWARD
THROUGH THE OHIO VALLEY EARLY THIS MORNING WITH WAVES RIPPLING
ALONG IT IN THE UPPER LEVELS. THIS IS RESULTING IN CONTINUED AREAS
OF ORGANIZED BUT FAIRLY SHALLOW CONVECTION FROM UPSTATE NY AND
PA...SOUTHWESTWARD ALONG THE WEST SIDE OF THE APPALACHIANS AND
INTO CENTRAL KY. AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS HAVE
GENERALLY BEEN WEAKENING AS THEY MOVE INTO THE WESTERN PORTIONS OF
OUR FCST AREA WITH WEST FLOW AND LITTLE TO NO INSTABILITY
REMAINING. ONE WAVE MAY BRING A MORE ORGANIZED AREA INTO THE WEST
DURING THE FRIST PART OF THE DAYLIGHT HOURS JUST AHEAD OF FRONTAL
BOUNDARY. FRONT WILL THEN PUSH ACROSS DURING THE DAY...BUT AS
USUAL NOT CLEANLY...WITH SOME LEE SIDE TROUGHING ALREADY EVIDENT
THIS MORNING...IT MAY SHIFT INTO THE PIEDMONT THIS
AFTERNOON...WITH DEEPER CONVECTION FIRING ACROSS THE EASTERN
PORTIONS OF OUR AREA OR MAYBE EVEN OFF TO THE EAST BY MID TO LATE
AFTERNOON. WITH TIMING OF POPS...GENERALLY FOLLOWED A BLEND OF THE
06Z RAP13 AND HIGH RES WRF-ARW FROM 00Z.
DO NOT THINK THERE WILL BE MANY BREAKS IN CLOUD COVER SO
INSTABILITY REMAINS WEAK TO MODEST...MAYBE 1000-1500 SFC BASED
MOST AREAS...WITH UP TO 2000 J/KG IN THE EAST IF WE CAN GET A FEW
BREAKS IN CLOUDS. DO NOT SEE MUCH IN THE WAY OF SEVERE WEATHER
POTENTIAL GIVEN VERY MOIST AIRMASS AND NOT ESPECIALLY STEEP LAPSE
RATES. LOCALLY HEAVY RAIN WILL BE MAIN CONCERN AGAIN...AND GIVEN
RAINFALL LAST EVENING AND SOME CONTINUED LIGHT TO MODERATE
OVERNIGHT IN FAR WEST...BIGGEST THREAT FOR ANY FLASH FLOODING
REMAINS IN THE WEST...EVEN THOUGH THERE IS SOME QUESTION AS TO
WHETHER ANY DEEPER CONVECTION CAN SUSTAIN ITSELF OR GET GOING
DURING THE MORNING HOURS BEFORE THE FRONT PUSHES THROUGH THE
MOUNTAINS. WILL KEEP THE FLASH FLOOD WATCH GOING THROUGH THE
DAY...ALTHOUGH AREAS IN THE FOOTHILLS VERY MARGINAL...AND WE WILL
LIKELY BE ABLE TO CANCEL EARLY AS BELIEVE ANY ORGANIZED CONVECTION
AND HEAVIER RAINFALL RATES WILL SHIFT EAST BY EARLY TO MID
AFTERNOON.
FRONT PUSHES WELL EAST BY EARLY EVENING IF NOT SOONER..QUICKLY
LOWERING THREAT OF SHWRS/STORMS ACROSS THE ENTIRE AREA BEFORE
MIDNIGHT. KEPT CHC POP GOING IN EAST UNTIL MIDNIGHT...BUT MY
FEELING IS THIS MAY MOVE OUT EVEN QUICKER. ALSO THERE IS LINGERING
LOW LEVEL MOISTURE ON WEST SLOPES BEHIND FRONT AND MAYBE SOME
SPRINKLES OR DRIZZLE IS POSSIBLE FOR A WHILE THIS EVENING BACK
THERE AS WELL...SO KEPT LOW CHC POPS INTO EARLY EVENING AS WELL.
TEMPERATURE WISE...AM LEANING TO COOLER MET GUIDANCE FOR HIGHS GIVEN
EXPECTED CLOUD COVER...AND EVEN NUDGED DOWN A DEG OR TWO FROM
THERE. ONE AREA THAT MAY END SEEING A LITTLE MORE SUN IS FAR
SOUTHEAST AND IF THERE ARE MORE THAN JUST A COUPLE HOURS OF IT
DURING TEH AFTERNOON THE LOW 90S TEMPS THE MAV IS ADVERTISING
COULD BE REALIZED...SO WILL HAVE TO WATCH THIS. TONIGHT WE MAY SEE
THE FIRST 50S IN THE WEST IN QUITE SOME TIME WITH LOWER DEW PTS
MOVING IN AND SOME CLEARING.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM EDT TUESDAY...
LOOKING AT MAINLY DRY CONDITIONS FOR WEDNESDAY...POSSIBLY WITH A FEW
LINGERING SHOWERS ACROSS OUR NORTHWEST WIND UPSLOPE AREAS DURING THE
MORNING...AS CANADIAN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
UPPER MIDWEST. THIS AIRMASS WILL BRING A SIGNIFICANT COOL DOWN TO OUR
AREA...WITH AFTERNOON HIGHS RANGING FROM 7 TO 9 DEGREES BELOW NORMAL
FOR MID AUGUST. HIGH PRESSURE WILL SHIFT EAST DURING THE DAY...AND
THEN BUILD SOUTHWARD ALONG THE EASTERN FACE OF THE APPALACHIANS
WEDNESDAY NIGHT...WHICH WILL SHIFT OUR WINDS TO A NORTHEASTERLY
DIRECTION.
THURSDAY WILL REMAIN RELATIVELY DRY AS WELL...ALTHOUGH MAY SEE A
LITTLE LIGHT RAIN ENTER THE NORTH CAROLINA MOUNTAINS AND THE
MOUNTAIN EMPIRE ON THURSDAY AS WINDS AROUND THE HIGH PRESSURE WEDGE
PICK UP MOISTURE FROM UPPER LEVEL DISTURBANCES RIDING ALONG THE COLD
FRONT STALLED WELL TO OUR SOUTH. RAINFALL WILL REMAIN ISOLATED
HOWEVER...AND WOULD NOT MAKE ANY CHANGES TO OUTDOOR PLANS AT THIS
POINT. THE COOL EASTERLY FLOW WILL AGAIN KEEP TEMPERATURES SEVERAL
DEGREES BELOW NORMAL...WITH MOST AREAS HOLDING IN THE 70S FOR
AFTERNOON HIGHS.
WILL SEE A BETTER RETURN OF MOISTURE FOR FRIDAY AS A DEEP UPPER
LEVEL TROUGH MOVES INTO THE CENTRAL MISSISSIPPI RIVER VALLEY. WHILE
HIGH PRESSURE WILL REMAIN IN PLACE IN THE LOW LEVELS...WINDS ALOFT
ALONG THE EASTERN SEABOARD WILL BECOME INCREASINGLY SOUTHWESTERLY AS
THE TROUGH AMPLIFIES. THIS UPPER FLOW WOULD BE FAVORABLE FOR
CARRYING DISTURBANCES ACROSS THE CAROLINAS...WHICH WOULD POTENTIALLY
TRIGGER SPOTTY SHOWERS AND THUNDERSTORMS FOR OUR AREA SOUTH OF
INTERSTATE 81.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 400 AM EDT TUESDAY...
AS WE PROGRESS INTO THE WEEKEND...CURRENT MODEL TRENDS OFFER A
STALLED DEEPENING LOW OVER THE CENTRAL U.S. WITH THE LOW ALONG THE
GULF BEING TRANSPORTED NORTHWARD ON THE EAST SIDE OF THE CENTRAL
CONUS TROUGH. THIS WOULD ALLOW FOR BETTER DYNAMICS AND MOISTURE FLOW
ACROSS THE REGION. THIS WILL LEAD TO BETTER CHANCE OF LIGHT TO
MODERATE RAIN OVER THE AREA THROUGH SATURDAY...AND THEN BETTER
CHANCES OF SHOWERS AND SOME THUNDERSTORMS BY SUNDAY. WHILE ACTIVITY
MAY TAPER OFF A BIT ON MONDAY...THE CENTRAL CONUS TROUGH WOULD STILL
BE TO OUR WEST...AND BE A FEATURE TO POTENTIALLY INFLUENCE OUR
WEATHER PAST DAY 7.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 200 AM EDT TUESDAY...
BETWEEN 06Z AND 12Z THERE WILL BE ANOTHER WAVE OF SHOWERS WITH
MODERATE RAINFALL AND ISOLATED THUNDER MOVING FROM KY INTO
SOUTHEAST WV AND LIKELY TO IMPACT BLF/LWB AGAIN WITH PERIODS OF
IFR CONDITIONS. LEFT MENTION OF THUNDER OUT OF LWB HOWEVER AS
LINGER WEAK INSTABILITY CONFINED A LITTLE FARTHER SOUTH. MORE
SHALLOW CONVECTION ORGANIZATION CONTINUES TO DEVELOP UPSTREAM SO
THERE MAY NOT BE TOO MANY BREAKS IN PRECIP ACTIVITY...AND FOG MAY
NOT BE AS DENSE AS ONCE EXPECTED AT LWB UNLESS SOME REAL BREAKS IN
PRECIP CAN OCCUR LATE. THUS MAKING FOR TROUBLESOME TAF
FORECAST ESPECIALLY AT THESE SITES. FARTHER EAST EXPECT A FEW
SHOWERS MAY REACH BCB/ROA/LYH BY 08Z TO 09Z BUT CIGS SHOULD REMAIN
VFR OR MVFR...WITH EXCEPTION OF BCB...BUT LIKELY TO GET SOME IFR
FOG FARTHER EAST LATE TONIGHT. OVERALL...EXPECT THE USUAL HARD TO
PIN DOWN FLUCTUATION BETWEEN IFR/LIFR TO VFR AT TIMES THROUGH
EARLY MORNING GIVEN THE TROPICAL AIRMASS AND THREAT OF SHOWERS.
FOR TUESDAY THE FRONT SHIFTS SLOWLY SOUTHEAST AND TURNS THE WINDS
TO THE WNW BY AFTERNOON. EXPECT MOST OF THE CONVECTION IN THE
MORNING IN THE WEST TO TRANSFER EAST OF THE MOUNTAINS IN THE
AFTERNOON. COVERAGE FOR SHOWERS SHOULD BE 50/50 AT LEAST IF NOT
MORE BUT KEPT THUNDER OUT OF THE PREDOMINANT GROUP FOR NOW...BUT
LEFT IN VICINITY. MAINLY VFR CONDITIONS FOR THE DAY...EXCEPT IN
THE CASE THAT ANY HEAVIER RAIN OR STORMS MOVE RIGHT OVER AN
AIRPORT.
THE COLD FRONT...AND ASSOCIATED HIGH PRESSURE...WILL LIKELY BE
STRONG ENOUGH TO PUSH THE TROPICAL AIRMASS OUT OF THE AREA FOR A
COUPLE OF DAYS...BRINGING A GOOD OPPORTUNITY FOR WIDESPREAD VFR
WEATHER THAT MAY LAST OVER MUCH OF THE AREA LATER TUESDAY NIGHT INTO
THURSDAY BEFORE MOISTURE BEGINS TO RETURN NORTHWARD ON THE BACK SIDE
OF THE HIGH LATE IN THE WEEK. ONE EXCEPTION WILL BE AT THE
SOUTHEASTERN WV TERMINAL FORECAST SITES WHERE RETURN TO VFR
WEATHER WITH NO FLIGHT RESTRICTIONS MAY BE DELAYED UNTIL MID TO
LATE WEDNESDAY DUE TO COOL UPSLOPING WINDS AND LINGERNIG LOW
CLOUDS AND PERHAPS EVEN SOME DRIZZLE TUES NIGHT.
&&
.HYDROLOGY...
AS OF 355 PM EDT MONDAY...
NO CHANGES TO FLASH FLOOD WATCH. SOME AREAS RECEIVED 3"+ OVER THE
MOUNTAIN EMPIRE OF SW VA...INCLUDING THE RICHLANDS AREA.
MORE HEAVIER DOWNPOURS ARE POSSIBLE AGAIN OVERNIGHT AND TUESDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR VAZ007-009>017-032.
NC...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NCZ001>003-018-019.
WV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR WVZ042>045.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...NF
LONG TERM...DS/NF
AVIATION...CF/SK/WP
HYDROLOGY...AMS/SK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
546 AM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENTLY...LOOKING AT MOSAIC RADAR...OUR CWFA IS PRETTY MUCH ECHO
FREE WITH A LINE OF THUNDERSTORMS PUSHING SOUTHEAST IN CENTRAL
NEBRASKA AT 1 AM THIS MORNING. FRONTAL BOUNDARY STILL LAYS UP
ALONG THE LARAMIE RANGE THIS MORNING...EXTENDING NORTHWEST INTO
CENTRAL MONTANA. TO OUR NORTH...A COMPLEX OF THUNDERSTORMS LAYS ACROSS
EASTERN MONTANA JUST EAST OF THE FRONT.
IT REMAINS TO BE SEEN WHAT THAT LINE OF THUNDERSTORMS OVER
NEBRASKA WILL DO TO OUR LOW LEVEL MOISTURE. IT HAS CAUSED WINDS TO
BECOME MORE SOUTHWESTERLY AND THEREFORE A LITTLE DRIER IN THE
PANHANDLE SO FAR. LATEST 11U-3.9U SATELLITE IMAGERY HAS YET TO
SHOW THE ANTICIPATED STRATUS DEVELOPING YET.
THE MORNING SHOULD START OFF DRY WITH INCREASING SHOWERS AND
THUNDERSTORMS DEVELOPING BY NOON. LATEST HRRR COMPOSITE
REFLECTIVITY FORECAST HAS SHOWERS DEVELOPING OVER THE MOUNTAINS TO
THE WEST OF CHEYENNE BY 17Z AND REALLY INCREASING IN COVERAGE
AFTER 19Z. THIS CORRESPONDS WELL WITH THE 00Z ECMWF FORECAST FOR
THE UPPER VORT MAX TO MOVE THROUGH THE UPPER RIDGE THIS AFTERNOON.
FORECAST STORM MOTIONS THIS AFTERNOON ON THE NAM SOUNDINGS SHOW
STORMS TO BE ALMOST STATIONARY. SOME LOCATIONS ARE GOING TO SEE
SOME HEAVY RAINFALL...LIKELY LEADING TO SOME FLASH FLOODING.
CONFIDENCE NO HIGH ON WHERE THESE THUNDERSTORMS ARE GOING TO
DEVELOP...SO WILL HOLD OFF ON ANY WATCHES. BUT DO EXPECT US TO BE
ISSUING FLASH FLOOD WARNINGS FOR SOME AREAS TODAY.
UPPER VORT MAX STAYS WITH US THROUGH THE OVERNIGHT HOURS
TONIGHT...FINALLY EXITING SOUTHEAST WEDNESDAY AFTERNOON. DID KEEP
FAIRLY HIGH POPS GOING TONIGHT THROUGH AT LEAST MIDNIGHT...THEN
PICKING UP AGAIN WEDNESDAY AFTERNOON WITH DAYTIME HEATING.
PATTERN CHANGE THEN BEGINS WEDNESDAY NIGHT INTO THURSDAY AS THE
ECMWF BUILDS THE UPPER LEVEL RIDGE. WITH THE BUILDING RIDGE...THE
DRIER AIR OVER UTAH AND SOUTHERN COLORADO WILL FILTER INTO THE
AREA DURING THE DAY THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 242 AM MDT TUE AUG 13 2013
ALL LONG RANGE MODELS IN AGREEMENT...SHOWING A BREAK IN THE
PERSISTENT MOIST WEATHER PATTERN ACROSS THE FORECAST AREA LATE
THIS WEEK. A DRYING TREND WILL CONTINUE THROUGH SATURDAY WITH
WARMER TEMPERATURES IN THE 80S AND LOW 90S EXPECTED. THE WARMEST
DAY WILL LIKELY BE SATURDAY AS THE RIDGE AXIS SHIFTS EASTWARD INTO
THE PLAINS...WITH HIGHS IN THE MID 80S TO MID 90S
EXPECTED...WARMEST ACROSS THE LOWER ELEVATIONS BELOW 5000 FEET.
KEPT POP BELOW 10 PERCENT WITH LIMITED CLOUD COVER. KEPT
TEMPERATURES A FEW DEGREES BELOW MOS FOR NOW...SINCE IT IS UNCLEAR
HOW THE CURRENT SOIL MOISTURE WILL IMPACT TEMPERATURES AND
HUMIDITY. WITH LIGHT WINDS EXPECTED...DO NOT BELIEVE THE NEAR
SURFACE MOISTURE WILL BE ADVECTED EASTWARD AS THAT QUICK.
PRECIPITATION CHANCES WILL RETURN TO THE AREA BY LATE SUNDAY AND
INTO MONDAY OF NEXT WEEK AS A FAST MOVING PACIFIC TROUGH PUSHES
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SOME COOLER AIR WILL PUSH
INTO THE REGION AS WELL WITH HIGH TEMPERATURES 5 TO 10 DEGREES
COOLER COMPARED TO FRIDAY/SATURDAY. INCREASED POP BETWEEN 20 TO 40
PERCENT FOR SHOWERS AND TSTORMS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 12Z TAF ISSUANCE)
LOW CIGS AND PATCHY FOG HAVE STRUGGLED TO DEVELOP ACROSS WESTERN
NEBRASKA EARLY THIS MORNING. KCDR WILL CONTINUE WITH A LOW CIG
AROUND 500 TO 1000 FEET AGL EARLY THIS MORNING BEFORE THE CLOUDS
LIFT AND DISSIPATE BY 14Z. ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS IS EXPECTED...FIRST DEVELOPING OVER SOUTHEAST WYOMING
EARLY THIS AFTERNOON WITH VCTS AT KRWL AND KLAR BY 19Z...AND THEN
MOVING EASTWARD ACROSS THE HIGH PLAINS BY MID TO LATE AFTERNOON.
THUNDERSTORMS MAY CONTAIN ERRATIC GUSTY WINDS UP TO 45 KNOTS...HEAVY
RAINFALL...AND FREQUENT LIGHTNING BEFORE DISSIPATING LATE THIS
EVENING.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENT THINKING IS THAT FIRE WEATHER CONCERNS WILL BE MINOR TODAY
AND WEDNESDAY AS MONSOONAL MOISTURE OVER WYOMING WILL CREATE
WIDESPREAD WETTING RAINS FOR MOST LOCATIONS. DRIER AIR BEGINS TO
MOVE INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. AFTERNOON
HUMIDITIES FORECAST TO BE IN THE SINGLE DIGITS ACROSS CARBON
COUNTY THURSDAY AFTERNOON. WINDS ARE EXPECTED TO REMAIN FAIRLY
LIGHT THOUGH AND SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1115 AM MDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 841 AM MDT TUE AUG 13 2013
HAVE CUT BACK POPS TO ZEROS...BASED ON NEAR ZERO CLOUDS ACROSS
THE CWA. WILL SEE A SLOW BUT STEADY INCREASE IN CONVECTION BY
THIS AFTERNOON...FIRST ACROSS THE MTS AND THEN SPREADING EWD TO
THE PLAINS. LOOKS LIKE A PRETTY TYPICAL AUG DAY. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 528 AM MDT TUE AUG 13 2013
...FLASH FLOOD THREAT FOR BURN SCARS IN EL PASO/TELLER COUNTIES TODAY...
MOST OF SHOWER/TSTORM ACTIVITY HAS DIMINISHED ACROSS THE AREA THIS
MORNING AND MODELS ARE HAVING A DIFFICULT TIME WITH THIS AS BOTH
NAM12 AND GFS MAINTAIN PRECIPITATION ACROSS THE SOUTHEAST PLAINS
THROUGH THE MORNING HOURS. THIS LEADS TO LOWER CONFIDENCE IN QPF
FORECAST TODAY AS MODELS PLAY CATCH UP WITH WHAT IS CURRENTLY GOING
ON.
IN WV PICS...APPEARS MAIN SHORTWAVE WHICH HELPED FIRE OFF
YESTERDAY`S CONVECTION HAS ALREADY PUSHED EAST OF THE AREA INTO
CENTRAL KS. HOWEVER...ANOTHER SHORTWAVE IS EVIDENT IN THE MOISTURE
PLUME ACROSS NW CO/SRN WY...WHICH WILL BE TRANSLATING SLOWLY
EASTWARD THROUGH THE UPPER RIDGE ACROSS THE AREA TODAY. AT THE
SFC...DEW POINTS HAVE INCREASED ACROSS THE PLAINS WITH READINGS
MAINLY IN THE 50S. STRATUS IS NOT AS WIDESPREAD AS MODELS
PORTRAYED...PROBABLY A RESULT OF THEIR OVERZEALOUS QPF FORECAST THIS
MORNING. SUSPECT WE WILL SEE SOME STRATUS DEVELOP AND SPREAD
WESTWARD INTO SOUTHEAST PLAINS TOWARDS DAWN BUT IT WILL PROBABLY BE
FAIRLY SHALLOW AND MORE PATCHY IN NATURE EXCEPT ACROSS THE SE CORNER
WHERE IT MAY BE MORE WIDESPREAD. THUS ANY STRATUS WILL LIKELY BURN
OFF FAIRLY QUICKLY THIS MORNING. WITH MORE CLEARING THIS
AFTERNOON...WE WILL BE MORE LIKELY TO SEE SUFFICIENT HEATING TO
TRIGGER ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHEAST MOUNTAINS AND ADJACENT PLAINS. WITH LOW LEVEL FLOW
REMAINING EASTERLY...DEW POINTS SHOULD REMAIN IN THE 50S ACROSS THE
PLAINS/I-25 CORRIDOR. THIS WILL LEAD TO CAPE VALUES GENERALLY
BETWEEN 500-1000 J/KG...NOT TERRIBLY HIGH...BUT SUFFICIENT TO
PRODUCE A FEW STRONG STORMS. THUS GREATEST CONCERN WILL BE THE EL
PASO/TELLER COUNTY AREAS WHERE THE SUSCEPTIBLE BURN SCARS WILL BE
UNDER THE GUN FOR MORE HEAVY RAINFALL TODAY. ALTHOUGH NAM12 HAS
TAMED DOWN ITS QPF FCST FOR TODAY VS YESTERDAY`S RUNS...OTHER MODELS
SUCH AS GFS...HIGH RES WRF (LOCAL AND NSSL)AND HRRR BOTH HIT
PORTIONS OF THE SE MTS/ADJACENT PLAINS WITH POCKETS OF HEAVY
RAINFALL. WITH THE SATURATED GROUND FROM RECENT RAINS ACROSS TELLER
AND EL PASO COUNTY...WILL BE PUTTING OUT ANOTHER FLASH FLOOD WATCH
FOR TODAY. GREATEST THREAT WINDOW APPEARS TO BE FROM 2 PM TO 6 PM
FOR THE BURN SCARS THOUGH HRRR SEEMS TO BE TRENDING IT TOWARDS 1 PM
IN SOME OF ITS LATER RUNS. OF COURSE IF THE STRONGER STORMS PASS
AROUND THE BURN SCARS...THEN IT IS POSSIBLE THAT FLASH FLOODING WILL
NOT OCCUR...BUT WILL ERR ON THE SIDE OF CAUTION AS THE PROBABILITY
WILL BE THERE FOR A HIGH IMPACT EVENT SHOULD THE BURN SCARS BE
IMPACTED. THE CITY OF COLORADO SPRINGS COULD ALSO BE UNDER THE GUN
TODAY FOR FLASH FLOODING DUE TO THE SATURATED GROUND FROM
YESTERDAY`S HEAVY RAIN WHICH WILL EXACERBATE ANY RUNOFF TODAY SHOULD
STORMS HIT THAT REGION.
THUNDERSTORMS SHOULD SPREAD EASTWARD ACROSS THE PLAINS DURING THE
LATE AFTERNOON AND EVENING HOURS AS THE SHORTWAVE SLOWLY KICKS
THROUGH THE REGION. WILL DECREASE POPS QUICKLY AFTER 06Z AS
CONSENSUS OF THE MODELS IS TO KEEP CONVECTION GOING WELL TO THE
SOUTH ALONG FRONTAL BOUNDARY ACROSS EASTERN NM/SRN TX PANHANDLE.
GFS SEEMS TO BE THE OUTLIER IN KEEPING WIDESPREAD QPF ACROSS THE
PLAINS THROUGH 12Z...SO WILL DISCOUNT IT FOR NOW. STRATUS SHOULD BE
MORE WIDESPREAD ACROSS THE SE PLAINS TONIGHT.
NOT TO NEGLECT WESTERN AREAS...DRIER AIR OUT THAT WAY SHOULD KEEP
PCPN EFFICIENCIES WITH THUNDERSTORMS LOWER. PRECIP WATERS WILL BE
RUNNING AROUND .50 WHICH PUTS THEM BELOW 100% OF NORMAL. WITH
FORCING FROM THE SHORTWAVE EXPECTED TO IMPACT NORTHERN AREAS MORE SO
THAN THE SOUTHWEST...EXPECT THUNDERSTORMS TO BE MORE ISOLATED TO
SCATTERED IN COVERAGE ACROSS THE EASTERN SAN JUANS AND LA
GARITAS...AND WILL DIMINISH QUICKLY DURING THE EVENING HOURS. THE
WEST FORK BURN SCAR WILL NEED TO BE MONITORED FROM NOON TO 6 PM FOR
POCKETS OF HEAVIER RAIN SUFFICIENT TO CAUSE LOCALIZED
RUNOFF/POTENTIAL FLASH FLOOD PROBLEMS. -KT
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 528 AM MDT TUE AUG 13 2013
LONGER TERM METEOROLOGICAL CONCERNS INCLUDE POPS AND TEMPERATURES.
ABOVE SEASONAL POPS IN COMBINATION WITH BELOW SEASONAL TEMPERATURES
ARE EXPECTED FROM WEDNESDAY INTO WEDNESDAY NIGHT AS AVAILABLE
ATMOSPHERIC MOISTURE INTERACTS WITH THE DAILY OROGRAPHIC HEATING
CYCLE AS WELL AS SOME UPPER LIFT.
RECENT LONGER TERM FORECAST MODEL SOUNDINGS INDICATE THAT
LOCATIONS SUCH AS THE I-25 CORRIDOR SHOULD EXPERIENCE PRECIPITABLE
WATER VALUES NEARING ONE INCH AT TIMES WEDNESDAY AFTERNOON.
THE COMBINATION OF AVAILABLE ATMOSPHERIC MOISTURE AND AN
APPROACHING UPPER SHORT-WAVE(PER LATEST GFS40 PV15 FORECAST)
...ESPECIALLY OVER NORTHERN SECTIONS OF THE FORECAST DISTRICT
SHOULD ALLOW FOR ANOTHER ROUND OF ISOLATED TO SCATTERED WEDNESDAY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE FORECAST
DISTRICT...ESPECIALLY EASTERN SECTIONS.
ONCE AGAIN...SOME OF THESE STORMS ON WEDNESDAY AFTERNOON AND
EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL AS
WELL AS POTENTIAL BURN SCAR FLOODING ISSUES...ESPECIALLY IF A
STRONGER STORM DEVELOPS OVER A BURN SCAR...SUCH AS THE WALDO
CANYON BURN SCAR...ETC. WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY AND ISSUE HYDRO/FLASH FLOOD HIGHLIGHTS/ADVISORIES/WARNINGS
AS NEEDED.
THEN...WARMER AND DRIER CONDITIONS SHOULD RETURN TO THE FORECAST
DISTRICT FROM LATER THURSDAY INTO AT LEAST EARLY SUNDAY AS AN
UPPER RIDGE BUILDS OVER ARIZONA AND NEW MEXICO. IN ADDITION...
FORECAST PRECIPITABLE WATER VALUES DROP TO BETWEEN 0.50 AND 0.70
INCHES OVER THE INTERSTATE 25 CORRIDOR DURING THIS TIME-FRAME.
GENERALLY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
SHOULD BE NOTED OVER THE CWFA FROM LATER THURSDAY INTO EARLY
SUNDAY. EVEN THOUGH RELATIVELY UNLIKELY DURING THIS
TIME-FRAME...PLEASE REMEMBER THAT IF A STRONGER STORM IMPACTS A
BURN SCAR...FLASH FLOODING WOULD BE POSSIBLE.
IN ADDITION...STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY ALSO
DEVELOP OVER PORTIONS OF THE FAR SOUTHEASTERN COLORADO PLAINS FROM
THURSDAY INTO THURSDAY EVENING AS PROJECTED LOCALIZED CAPES/LIS IN
EXCESS OF 2000 J/KG AND -7C RESPECTIVELY INTERACT WITH PROJECTED
0 TO 6 KM BULK SHEAR VALUES AROUND 40 KNOTS.
INCREASED SHOWER AND THUNDERSTORM ACTIVITY IS THEN ANTICIPATED
FROM LATER SUNDAY INTO NEXT TUESDAY AS A NORTHERLY SURFACE SURGE
MOVING ACROSS EASTERN SECTIONS MONDAY INCREASES ATMOSPHERIC
MOISTURE AND INTERACTS WITH UPPER SHORTWAVES. FORECAST MODEL
SOUNDINGS PROJECT THAT PRECIPITABLE WATER VALUES OVER THE
INTERSTATE 25 CORRIDOR INCREASE TO OVER ONE INCH BY MONDAY
AFTERNOON.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR LOCALIZED
HEAVY RAIN AND ASSOCIATED FLASH FLOODING CONCERNS(ESPECIALLY OVER
THE AREA BURN SCARS) WILL BE POSSIBLE FROM LATER SUNDAY INTO NEXT
TUESDAY. AS ALWAYS...WFO PUEBLO WILL MONITOR CLOSELY.
FINALLY...LOW-GRADE GRADIENT WINDS AS WELL AS ABOVE AVERAGE
MID-AUGUST SEASONAL TEMPERATURES ARE ANTICIPATED OVER THE
MAJORITY OF THE FORECAST DISTRICT FROM THURSDAY INTO NEXT MONDAY
WITH THE WARMEST CONDITIONS EXPECTED THIS WEEKEND AS 700 MB
TEMPERATURES ALONG THE I-25 CORRIDOR CLIMB TO AROUND 18C FROM THE
12C READINGS PROJECTED TODAY. MAXIMUM TEMPERATURES THIS WEEKEND
OVER MANY SECTIONS OF THE SOUTHEASTERN COLORADO PLAINS SHOULD
REACH WELL INTO THE 90S BOTH SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 11:15 MDT TUE AUG 13 2013
MAIN AVN CONCERN CONTINUES TO BE POTENTIAL FOR TS AT THE TAF SITES
THIS AFTERNOON AND EVE...FROM 20-21Z AT KALS AND KCOS...AND 22-24Z
FOR KPUB. COULD SEE SOME BRIEF HEAVY RAINFALL AND MVFR TO BRIEFLY
IFR CONDITIONS IN THE HEAVIEST STORMS. ALSO SOME SMALL HAIL POSSIBLE.
STORMS WILL MOVE TOT HE EAST AND SHOULD CLEAR THE TERMINALS BY
SUNSET OR SHORTLY AFTER...WITH JUST SOME LINGERING SHOWERS THIS
EVE. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ081-084-085.
&&
$$
UPDATE...ROSE
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS TAUNTON MA
347 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND EMBEDDED
THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL THROUGH THIS EVENING.
DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY AND CONTINUES INTO
THIS WEEKEND.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
***SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING LATE THIS AFTERNOON***
4 PM UPDATE...MUCH OF THE RAIN HAS DISSIPATED OR MOVED OFFSHORE IN
THIS AREA. EXCEPTIONS TO THIS ARE THE CAPE AND ISLANDS WHERE STORMS
ARE MOVING ACROSS NOW. THE STRONGEST OF THESE STORMS REMAIN WELL
SOUTH OF SOUTHERN NEW ENGLAND AND THE OUTER COASTAL WATERS. THAT
SAID...THIS HAS BEEN WELL FORECAST BY THE HRRR MODEL. THE HRRR IS
ALSO ACCURATELY FORECASTING ADDITIONAL SHOWERS AND THUNDERSTORMS IN
NEW YORK STATE JUST AHEAD OF THE COLD FRONT. THESE ARE FORECAST NOT
TO MOVE INTO OUR AREA UNTIL CLOSE TO 00Z...AT WHICH POINT
INSTABILITY IS LIKELY TO BE MORE LIMITED THAN IT ALREADY IS.
HOWEVER...THERE ARE STARTING TO BE SOME INDICATIONS OF CLEARING
ACROSS NEW YORK STATE AND EVEN A BIT INTO THE CONNECTICUT VALLEY IN
MASS AND CONNECTICUT. IF THIS CLEARING CONTINUES...IT MAY PRODUCE
ENOUGH INSTABILITY TO SUSTAIN THESE STORMS.
IF THE STORMS SUSTAIN THEMSELVES...THERE IS POTENTIAL FOR LOCALLY
HEAVY RAINFALL AND POSSIBLY URBAN AND POOR DRAINAGE FLOODING. IN
ADDITION...THE ENVIRONMENT IS THE SAME HIGH SHEAR...LOW CAPE
ENVIRONMENT WE HAVE BEEN IN MUCH OF THE SUMMER. THEREFORE...THERE IS
A POTENTIAL FOR STRONG WINDS WITH THE STRONGEST STORMS.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
TONIGHT...LINGERING SHOWERS SHOULD COME TO AN END SHORTLY AFTER
MIDNIGHT IF NOT BEFORE. THEN CLEARING FROM WEST TO EAST AS THE COLD
FRONT MOVES THROUGH AND DRIER AIR STARTS MOVING IN. TEMPERATURES
OVERNIGHT WILL REMAIN FAIRLY MILD WHILE THE DRY AIR MOVES IN.
WEDNESDAY AND WEDNESDAY NIGHT...HIGH PRESSURE STARTS BUILDING INTO
THE REGION. A REASONABLY STRONG LOW LEVEL JET AND DECENT MIXING
WILL RESULT IN GUSTY WINDS DURING THE DAY WHICH WILL PRECLUDE SEA
BREEZES FROM DEVELOPING. OTHERWISE...QUIET WEATHER EXPECTED WITH
BELOW NORMAL TEMPERATURES MORE REMINISCENT OF SEPTEMBER THAN OF MID
AUGUST.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER THROUGH THIS WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/12Z GUIDANCE CONTINUES TO DECENT OVERALL SYNOPTIC AGREEMENT
THROUGH MUCH OF THIS PERIOD.
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK MID-LEVEL CUTOFF IS
PROGGED TO MOVE INTO THE CANADIAN MARITIMES...WITH ANOTHER MID-
LEVEL CUTOFF MOVING FROM HUDSON BAY TO SOUTHEAST CANADA TOWARD
THE END OF THIS WEEK. THIS SETS UP A PATTERN WITH A BROAD MID-
LEVEL TROUGH OVER SOUTHEAST CANADA...WITH A WEAKER SOUTHERN
BRANCH OF THE JET STREAM CONVERGING NEAR THE MARITIMES. THE END
RESULT SHOULD BE PERSISTENT RIDGING NEAR OR OVER SOUTHERN NEW
ENGLAND THROUGH MUCH OF THE EXTENDED FORECAST. STAYED CLOSE TO THE
CONSENSUS SOLUTION...UNTIL SOME OF THE FINER DETAILS CAN BE BETTER
RESOLVED.
THURSDAY INTO
AS A SECOND CUTOFF DIVES S FROM HUDSON BAY
IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE NORTHEAST
CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND CUTOFF LOOK TO
HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING ALONG THE
SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE ATLANTIC
TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE NORTHEAST.
GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL MODELS AND
THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH CONFIDENCE THAT
THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST THROUGH EARLY NEXT
WEEK. GIVEN THIS...WILL USE A GFS/ECMWF BLEND AS A BASELINE FOR
THIS FORECAST UPDATE.
TEMPERATURES SHOULD SLOWLY RISE THROUGH THIS PORTION OF THE
FORECAST...BUT REMAIN SEASONABLE. COMFORTABLE HUMIDITY LEVELS
THROUGH FRIDAY...WILL SLOWLY INCREASE THIS WEEKEND INTO EARLY NEXT
WEEK. THERE IS SOME QUESTION AS TO HOW CLOSE A LOW PRESSURE WILL
GET TO OUR REGION EARLY NEXT WEEK. AT THIS JUNCTURE...THINKING IT
WILL REMAIN WELL TO OUR SOUTH...SO KEPT THE FORECAST DRY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
WEDNESDAY AND WEDNESDAY NIGHT.
THROUGH 00Z...RAIN WITH EMBEDDED THUNDERSTORMS ALONG SOUTH
COAST...CAPE...AND ISLANDS. ISOLD TO SCT SHRA ELSEWHERE. GENERALLY
IFR IN THE MAIN BATCH OF RAIN WITH IFR TO VFR CONDITIONS
ELSEWHERE. IFR CONDITIONS WILL BE MOSTLY DUE TO POCKETS OF
HEAVIER RAIN. EXACT TIMING REMAINS UNCERTAIN.
TONIGHT...LOW PROBABILITY OF A LINE OF SHOWERS AND THUNDERSTORMS
MOVING INTO WESTERN ZONES RIGHT AROUND 00Z. OTHERWISE...MAY SEE
SOME LINGERING LOW CLOUDS AND FOG PATCHES PERSIST AT SOME
/ESPECIALLY EASTERN/ TERMINALS INTO THE OVERNIGHT HOURS. AREAL
COVERAGE OF LOW CLOUDS AND FOG PATCHES ARE UNCERTAIN.
WEDNESDAY...ANY LEFTOVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
WEDNESDAY NIGHT...VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN THIS EVENING.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE VFR. LOW CONFIDENCE FOR IFR IN PATCHY FOG AND LOW
CLOUDS LATE THURSDAY NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN WATERS THIS
AFTERNOON WITH ANOTHER ROUND OF ISOLATED TO SCATTERED STORMS LATE
THIS EVENING. THESE STORMS WILL LIMIT VISIBILITIES. EXPECT
CLEARING LATE TONIGHT WITH FAIRLY QUIET WEATHER WEDNESDAY AND
WEDNESDAY NIGHT. THERE IS POTENTIAL FOR 5 FOOT SEAS AND WESTERLY
WINDS GUSTING TO 25 KTS ON THE OUTER WATERS. WITH THE NICE BOATING
WEATHER EXPECTED...HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE OUTER
WATERS FOR WEDNESDAY AND WEDNESDAY NIGHT.
OUTLOOK...THURSDAY THROUGH SUNDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS A HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND
THE WATERS BUT WILL REMAIN BELOW 20 KTS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 5 AM EDT THURSDAY
FOR ANZ250-254>256.
&&
$$
SYNOPSIS...RLG/BELK
NEAR TERM...RLG
SHORT TERM...RLG
LONG TERM...BELK
AVIATION...RLG/BELK
MARINE...RLG/BELK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
203 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BRING SHOWERS AND EMBEDDED
THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL THROUGH THIS EVENING.
DRY AND SEASONABLE WEATHER RETURNS WEDNESDAY AND CONTINUES INTO
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
***SHOWERS AND EMBEDDED THUNDERSTORMS MAY BRING LOCALLY HEAVY
RAINFALL/POOR DRAINAGE STREET FLOODING LATE THIS AFTERNOON***
2 PM UPDATE...MUCH OF THE RAIN HAS DISSIPATED OR MOVED OFFSHORE IN
THIS AREA. EXCEPTIONS TO THIS ARE SOUTHERN RHODE ISLAND AND
SOUTHEASTERN MASSACHUSETTS INCLUDING THE CAPE AND ISLANDS WHERE
STORMS MOVING NORTHEASTWARD FROM NEW JERSEY ARE TRACKING. THE
STRONGEST OF THESE STORMS REMAIN WELL SOUTH OF SOUTHERN NEW
ENGLAND...POSSIBLY ONLY CLIPPING THE SOUTHERN OUTER COASTAL
WATERS. THAT SAID...THIS IS VERY SIMILAR TO THE HRRR MODEL THAT
FORECASTS ADDITIONAL SHOWERS AND THUNDERSTORMS FORMING IN NEW YORK
STATE JUST AHEAD OF THE COLD FRONT. THESE STORMS HAVE DEVELOPED
JUST EAST OF LAKE ONTARIO SOUTHWARD INTO CENTRAL PENNSYLVANIA AND
WILL SLOWLY MAKE THEIR WAY EASTWARD. THESE ARE FORECAST NOT TO MOVE
INTO OUR AREA UNTIL CLOSE TO 00Z...AT WHICH POINT INSTABILITY IS
LIKELY TO BE MORE LIMITED THAN IT ALREADY IS. HOWEVER...THERE ARE
STARTING TO BE SOME INDICATIONS OF CLEARING ACROSS NEW YORK STATE
AND EVEN A BIT INTO THE CONNECTICUT VALLEY IN MASS AND
CONNECTICUT. IF THIS CLEARING CONTINUES...IT MAY PRODUCE ENOUGH
INSTABILITY TO SUSTAIN THESE STORMS.
IF THE STORMS SUSTAIN THEMSELVES...THERE IS GOOD POTENTIAL FOR
LOCALLY HEAVY RAINFALL AND POSSIBLY URBAN AND POOR DRAINAGE
FLOODING. IN ADDITION...THE ENVIRONMENT IS THE SAME HIGH
SHEAR...LOW CAPE ENVIRONMENT WE HAVE BEEN IN MUCH OF THE SUMMER.
THEREFORE...THERE IS A POTENTIAL FOR STRONG WINDS WITH THE
STRONGEST STORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
TONIGHT...
A FEW SHOWERS AND ISOLATED THUNDERSTORMS MAY LINGER DURING THE
EVENING ESPECIALLY ALONG THE COAST. OTHERWISE...MUCH DRIER MID
LEVEL AIR WILL WORK INTO THE REGION BY LATE EVENING BRINGING AN END
TO MOST OF THE PRECIPITATION. MAY SEE SOME PATCHY GROUND FOG
DEVELOP IN THE TYPICALLY PRONE LOCATIONS...ESPECIALLY IN AREAS THAT
SEE A FAIR AMOUNT OF RAIN TODAY. LOW TEMPS WILL MAINLY BE IN THE
UPPER 50S AND LOWER 60S.
WEDNESDAY...
A MIXTURE OF CLOUDS/SUN ALONG WITH GUSTY NORTHWEST WINDS BEHIND THE
COLD FRONT ON WED. LOW RISK OF A BRIEF SPRINKLE/SPOT SHOWER ACROSS
OUR FAR NORTHWEST ZONES...BUT BASICALLY A DRY AND BEAUTIFUL DAY
EXPECTED FOR THE MIDDLE OF AUGUST. HIGH TEMPS WILL MAINLY BE IN THE
70S WITH LOW HUMIDITY. IN FACT...SOME OF THE HIGHEST TERRAIN WILL
STRUGGLE TO REACH 70!
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* QUIET...SEASONABLE WEATHER WED THRU THE WEEKEND
* POSSIBILITY OF SOME RAIN EARLY NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
13/00Z LONG RANGE GUIDANCE CONTINUES TO SHOW QUITE GOOD AGREEMENT
THROUGH MUCH OF THE LONG TERM. INITIAL WEAK CUTOFF IS PROGGED TO
SLIDE INTO THE CANADIAN MARITIMES AS A SECOND CUTOFF DIVES S FROM
HUDSON BAY IN THE PERSISTENT BROAD TROF OVER ERN CANADA AND THE
NORTHEAST CONUS. HOWEVER...THE LONGWAVE TROF AND THIS SECOND
CUTOFF LOOK TO HAVE LITTLE EFFECT ON THE REGION AS STRONG RIDGING
ALONG THE SOUTHERN HALF OF THE CONUS COMBINES WITH RIDGING IN THE
ATLANTIC TO YIELD SUBSIDENCE AND BROAD SFC HIGH PRES OVER THE
NORTHEAST. GIVEN THERE IS GOOD AGREEMENT BETWEEN BOTH OPERATIONAL
MODELS AND THEIR COUNTERPART ENSEMBLES...HAVE REASONABLY HIGH
CONFIDENCE THAT THIS HIGH PRES WILL YIELD A MOSTLY DRY FORECAST
THROUGH EARLY NEXT WEEK. GIVEN THIS...WILL USE A GFS/ECWMF BLEND
AS A BASELINE FOR THIS FORECAST UPDATE.
WED NIGHT INTO FRI...
HIGH PRES GRADUALLY SLIDES IN FROM THE W THROUGH THE PERIOD. WITH
THE HIGH PRES CENTER REMAINING W OF THE REGION...EXPECT US TO
REMAIN ON THE COOLER SIDE OF THE HIGH INITIALLY. H85 TEMPS RANGE
BETWEEN +8C AND ABOUT +11C...SO HIGHS SHOULD START THU AROUND THE
MID 70S...INCREASING TO THE UPPER 70S AND LOW 80S BY FRI AFTER
SOME AIRMASS MODIFICATION. OVERNIGHT MINS WILL BE ON THE COOL SIDE
WITH LOW HUMIDITY /AND THEREFORE LOW DWPTS/ WITH LIGHT FLOW AND
CLEAR SKIES. EXPECTING MINS DIPPING AS LOW AS THE MID 40S IN
NORMALLY COOLER SPOTS. MID 50S IN THE WARMER SPOTS.
THIS COMING WEEKEND...
A WARM FRONT IS EXPECTED TO BEGIN A GRADUAL SLIDE TO THE N
THROUGH THE WEEKEND...BUT WITH HIGH PRES IN PLACE OVER THE REGION
AND VERY SLOWLY SLIDING TO THE E...EXPECTING MOSTLY DRY CONDITIONS
ACROSS SRN NEW ENGLAND DESPITE THIS APPROACHING FRONT. GFS
CURRENTLY SUGGESTS HIGHEST POTENTIAL FOR SOME PRECIP...BUT IT TOO
KEEPS MOST OF ITS GENERATED QPF TO THE W. MID LVL TEMPS DO
INCREASE SOMEWHAT...REACHING +10 TO +13C...SO TEMPS LEAN NEAR TO
SLIGHTLY WARMER THAN NORMAL.
EARLY NEXT WEEK...
DIFFERENCES IN THE TIMING OF A STRONGER SHORTWAVE EFFECTING THE
REGION GIVES WAY TO LOWER CONFIDENCE HERE...BUT IT APPEARS THAT
THERE WILL BE A BIT HIGHER CHANCE FOR SOME PRECIP PARTICULARLY BY
TUE. WILL BE INCREASING TO SOME SLIGHT CHANCE POPS...CLOSER TO THE
ECWMF SOLUTION...WHICH SUGGESTS THE WARM FRONT LIFTS FAR ENOUGH N
TO AFFECT THE REGION WITH THIS SHORTWAVE PASSAGE.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...MODERATE CONFIDENCE TODAY AND TONIGHT. HIGH CONFIDENCE
WEDNESDAY AND WEDNESDAY NIGHT.
THROUGH 00Z...RAIN WITH EMBEDDED THUNDERSTORMS ALONG SOUTH
COAST...CAPE...AND ISLANDS. ISOLD TO SCT SHRA ELSEWHERE. GENERALLY
IFR IN THE MAIN BATCH OF RAIN WITH IFR TO VFR CONDITIONS
ELSEWHERE. IFR CONDITIONS WILL BE MOSTLY DUE TO POCKETS OF
HEAVIER RAIN. EXACT TIMING REMAINS UNCERTAIN.
TONIGHT...LOW PROBABILITY OF A LINE OF SHOWERS AND THUNDERSTORMS
MOVING INTO WESTERN ZONES RIGHT AROUND 00Z. OTHERWISE...MAY SEE
SOME LINGERING LOW CLOUDS AND FOG PATCHES PERSIST AT SOME
/ESPECIALLY EASTERN/ TERMINALS INTO THE OVERNIGHT HOURS. AREAL
COVERAGE OF LOW CLOUDS AND FOG PATCHES ARE UNCERTAIN.
WEDNESDAY...ANY LEFTOVER MVFR-IFR CONDITIONS IN SCATTERED LOW
CLOUDS/FOG PATCHES WILL IMPROVE TO VFR NOT LONG AFTER SUNRISE.
OTHERWISE...VFR CONDITIONS.
WEDNESDAY NIGHT...VFR.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING. MAY SEE BOUNCING BETWEEN VFR AND LOWER CATEGORIES WITH
RAIN THIS EVENING.
KBDL TERMINAL...MODERATE CONFIDENCE IN TRENDS. LOW CONFIDENCE IN
TIMING.
OUTLOOK...THURSDAY THROUGH SATURDAY...
HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY AND TONIGHT...HIGH CONFIDENCE. WINDS AND SEAS WILL REMAIN
BELOW SCA THRESHOLDS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. THE MAIN CONCERN EARLY THIS MORNING WILL BE FOR DENSE FOG
ACROSS OUR SOUTHERN WATERS. THIS FOG SHOULD BURN OFF TO AT LEAST
SOME DEGREE BY MID TO LATE MORNING. THE OTHER CONCERN WILL BE FOR
EMBEDDED THUNDERSTORMS TO WORK ACROSS THE WATERS...MAINLY THIS
AFTERNOON AND EVENING.
WEDNESDAY...MODERATE CONFIDENCE. NORTHWEST WIND GUSTS OF 25 KNOTS
ARE EXPECTED NEAR SHORE WITH GOOD MIXING BEHIND THE COLD FRONT. ITS
3RD PERIOD SO DID NOT GO WITH ANY HEADLINES AT THIS POINT...BUT
LATER SHIFTS MAY NEED TO CONSIDER A SCA FOR SOME OF OUR NEAR SHORE
WATERS. MAY ALSO SEE SOME 3 TO 5 FOOT SEAS DEVELOP ACROSS OUR
SOUTHERN MOST ATLANTIC WATERS...WHICH MAY ALSO NEED TO BE CONSIDERED
FOR HEADLINES.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
HIGH CONFIDENCE. QUIET BOATING WEATHER EXPECTED. WINDS WILL SHIFT
DIRECTION AS HIGH PRESSURE BUILDS OVER SOUTHERN NEW ENGLAND AND THE
WATERS BUT WILL REMAIN BELOW 25 KTS...SAVE FOR POSSIBLY WED
EVENING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY/RLG
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY/RLG
MARINE...FRANK/DOODY
AREA FORECAST DISCUSSION
NWS ALBANY NY
145 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON WITH
ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM. IN ITS WAKE...COOLER
AND LESS HUMID AIR WILL RETURN TO THE REGION FOR TOMORROW. THROUGH
THE REMAINDER OF THE WEEK...HIGH PRESSURE WILL ALLOW FOR DRY
CONDITIONS...WITH TEMPERATURES SLOWLY MODERATING BACK TOWARDS NORMAL
LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EDT...WE HAD A PRETTY HEAVY BATCH OF RAIN (WITH
EMBEDDED THUNDERSTORMS) MOVE THROUGH PORTIONS OF THE REGION...WITH
THE HEAVIEST RAINFALL FALLING TO THE EAST OF THE CAPITAL DISTRICT
WHERE RAINFALL ESTIMATED APPROACHING TWO INCHES. PLEASE REFER TO OUR
LATEST PUBLIC WEATHER STATEMENTS (PNS) FOR ALL THE LATEST RAINFALL
REPORTS.
THIS BATCH OF RAIN HAS MOSTLY MOVED TO THE EAST OF THE HUDSON
VALLEY..WITH SOME POCKETS OF MODERATE TO HEAVY RAINFALL IN DUTCHESS
COUNTY AS WELL AS PORTIONS OF SOUTHERN VERMONT. THERE WERE WIDELY
SCATTERED LIGHT SHOWERS STILL AROUND MAINLY ACROSS THE MOHAWK VALLEY.
HOWEVER...ANOTHER LINE OF SHOWERS WERE DEVELOPING RIGHT AHEAD OF THE
COLD FRONT...LOCATED IN CENTRAL NEW YORK. THE HRRR AND HIRESWRF BOTH
HAVE THIS LINE OF SHOWERS COMING THROUGH. FOR ONCE...THESE MODELS
HAVE APPEARED TO DONE FAIRLY WELL WITH THE EVOLUTION OF THE RAINFALL
THUS FAR. THEREFORE...WILL LEAN WITH ITS SOLUTION OF BRINGING
ANOTHER LINE OF NUMEROUS SHOWERS OUR WAY THIS AFTERNOON. THIS LINE
LOOKS TO MOVE THROUGH BETWEEN ABOUT 100 PM (NORTHWEST) TO ABOUT 800
PM (SOUTHEAST). WINDS OFF THE DECK LOOK TO BACK TO THE SOUTHEAST
WILL WOULD HELP ENHANCED CONVERGENCE AND UPWARD MOTION WITH THE
FRONT.
INSTABILITY IS VERY LIMITED...GENERALLY UNDER 1000/J SO AT THIS
TIME...WE ARE FAIRLY CONFIDENT THERE WILL BE NO SEVERE OR EVEN
STRONG THUNDERSTORM ACTIVITY. ONE THING TO NOTE...THERE IS SOME
PRETTY LOW LEVEL WIND WITH THE LOWER WINDS SSE BECOMING WSW QUICKLY
AS ONE GOES THROUGH NEAR THE GROUND THROUGH ABOUT 5000 FEET. THERE
COULD BE SOME WEAK LOW LEVEL ROTATION BUT AGAIN WITH VERY LIMITED
INSTABILITY NOTHING ELSE IS EXPECTED...OTHER THAN PERHAPS A LITTLE
MORE HEAVY RAINFALL.
MAX TEMPS LOOK TO BE THE HELD IN THE LOW TO MID 70S TODAY. TEMPS
WILL ONLY REACH THE UPPER 60S ACROSS THE HIGHEST TERRAIN.
THE FRONT WILL CROSS DURING THE EARLY EVENING HOURS. THIS WILL BRING
AN END TO THE RAIN SHOWERS. SOME LINGERING SHOWERS ARE POSSIBLE
ACROSS NORTHERN AREAS TONIGHT AS THE UPPER TROUGH APPROACHES AND
PASSES JUST TO THE NORTH. WITH COOLER AIR STARTING TO MOVE IN BEHIND
THE COLD FRONT...MIN TEMPS WILL DROP INTO THE 50S OVERNIGHT AND
DEWPOINTS WILL FALL DURING THE OVERNIGHT HOURS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE OHIO VALLEY FOR
THE ENTIRE SHORT TERM PERIOD. IT LOOKS TO BE MAINLY DRY ACROSS
THE REGION WITH COMFORTABLE HUMIDITY LEVELS AND BELOW NORMAL
TEMPERATURES. THE EXCEPTION TO THE DRY WEATHER WILL BE DURING THE
DAY ON WEDNESDAY ACROSS THE ADKS...WHERE COOL TEMPS ALOFT WILL
ALLOW FOR THE FORMATION OF SOME SCATTERED LIGHT RAIN SHOWERS.
MAX TEMPS ON WED AND THURSDAY WILL BE IN THE LOW TO MID 70S FOR
VALLEY AREAS /60 ACROSS THE HIGH TERRAIN. MIN TEMPS WILL GENERALLY
BE IN THE LOW 50S /40S FOR THE HIGH TERRAIN AND OUTLYING AREAS/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRY AND TRANQUIL WEATHER IS EXPECTED FOR THE PERIOD. RIDGING IS
EXPECTED TO DOMINATE AT THE SURFACE WITH HEIGHTS ALOFT GRADUALLY
RISING WITH RIDGING BUILDING IN ACROSS THE WESTERN ATLANTIC.
A WAVE OF LOW PRESSURE IS EXPECTED TO MOVE EASTWARD ALONG A STALLED
FRONTAL BOUNDARY ACROSS THE SOUTHEASTERN UNITED STATES. THE BOUNDARY
IS EXPECTED TO SHIFT NORTHWARD OVER THE WEEKEND. HOWEVER IT APPEARS
PRECIPITATION ASSOCIATED WITH THIS FEATURE SHOULD REMAIN TO OUR
SOUTH...SO LOOKING AT DRY WEATHER THROUGH THE WEEKEND INTO EARLY
NEXT WEEK.
SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS MAINLY IN THE MID
70S TO LOWER 80S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
MOST OF THE RAIN HAS MOVED EAST OF THE TAF SITES. STILL SOME
PATCHES OF LIGHT RAIN...ONE OVER KGFL AND ONE OVER KPOU.
CONDITIONS SHOULD GRADUALLY IMPROVE OVER THE NEXT COUPLE OF HOURS
BEFORE ANOTHER ROUND OF SHOWERS AND POSSIBLY A THUNDERSTORM ARRIVE
AHEAD OF THE COLD FRONT. DO NOT HAVE THUNDERSTORMS SPECIFICALLY
MENTIONED IN TAFS AT TIME. NOT MANY LIGHTNING STIKES UPSTREAM. LATER
SHIFTS WILL MONITOR AND AMEND AS NECESSARY. CONDITIONS SHOULD
IMPROVE TO VFR FOR A PERIOD THIS EVENING INTO THE
OVERNIGHT...HOWEVER A RETURN TO MVFR IS ANTICIPATED WITH IFR
POSSIBLE AT KGFL AND KPSF.
LIGHT SOUTHERLY WINDS WILL SHIFT TO THE WEST AND NORTHWEST WITH THE
PASSAGE OF THE COLD FRONT THIS EVENING. WINDS WILL BE STRONG AND
GUSTY FROM THE NORTHWEST ON WEDNESDAY...GUSTING TO 25 KNOTS.
OUTLOOK...
WED-SAT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES EXPECTED OVER THE NEXT FEW DAYS.
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A FRONTAL BOUNDARY IS
EXPECTED TODAY. RAINFALL AMOUNTS LOOK TO AVERAGE AROUND ONE HALF
INCH...LOCALLY OVER AN INCH WHERE HEAVIER SHOWERS OR
THUNDERSTORMS TAKE PLACE. THIS WILL BRING A WETTING RAIN TO THE
REGION.
RH VALUES WILL ONLY DROP TO 70 TO 80 PERCENT TODAY DUE TO CLOUDS AND
RAIN. THEY WILL BE NEAR 100 PERCENT TONIGHT AND DROP TO AROUND 40
TO 60 PERCENT TOMORROW AFTERNOON.
LARGE CANADIAN HIGH PRESSURE LOOKS TO TAKE CONTROL OF OUR WEATHER
WEDNESDAY THROUGH AT LEAST FRIDAY WITH DRY WEATHER.
&&
.HYDROLOGY...
AN APPROACHING FRONTAL BOUNDARY WILL BRING A ROUND OF RAIN SHOWERS
AND POSSIBLE THUNDERSTORMS TO THE REGION TODAY. PWAT VALUES WILL RISE
TO AROUND 1.50-1.75 INCHES INCHES AHEAD OF THE FRONTAL BOUNDARY.
WHILE ANY SHOWER OR THUNDERSTORM WILL BE CAPABLE OF HEAVY
DOWNPOURS...THE ATMOSPHERE IS NOT QUITE AS MOIST AS LATE LAST WEEK
WHEN SOME FLASH FLOODING OCCURRED ACROSS THE MID HUDSON VALLEY AND
NW CT. IN ADDITION...STRONG FLOW ALOFT SHOULD KEEP ANY SHOWERS OR
THUNDERSTORMS MOVING RATHER QUICKLY. AS A RESULT...FLASH FLOODING
IS NOT ANTICIPATED WITH THIS STORM SYSTEM. SOME MINOR RISES WILL
BE POSSIBLE ON AREA RIVERS AND STREAMS...ESPECIALLY ACROSS THOSE
AREAS THAT SAW HEAVIER RAIN LAST WEEK. THERE STILL COULD BE
PONDING ON ROADWAYS AND AREAS OF POOR DRAINAGE THROUGH TUESDAY
EVENING.
DRY WEATHER WILL RETURN BY LATE TONIGHT AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER AND STREAMS LEVELS TO
RECEDE ONCE MORE.
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/HWJIV
NEAR TERM...SND/HWJIV
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...SND
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON WITH
ADDITIONAL SHOWERS AND PERHAPS A THUNDERSTORM. IN ITS WAKE...COOLER
AND LESS HUMID AIR WILL RETURN TO THE REGION FOR TOMORROW. THROUGH
THE REMAINDER OF THE WEEK...HIGH PRESSURE WILL ALLOW FOR DRY
CONDITIONS...WITH TEMPERATURES SLOWLY MODERATING BACK TOWARDS NORMAL
LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM EDT...WE HAD A PRETTY HEAVY BATCH OF RAIN (WITH
EMBEDDED THUNDERSTORMS) MOVE THROUGH PORTIONS OF THE REGION...WITH
THE HEAVIEST RAINFALL FALLING TO THE EAST OF THE CAPITAL DISTRICT
WHERE RAINFALL ESTIMATED APPROACHING TWO INCHES. PLEASE REFER TO OUR
LATEST PUBLIC WEATHER STATEMENTS (PNS) FOR ALL THE LATEST RAINFALL
REPORTS.
THIS BATCH OF RAIN HAS MOSTLY MOVED TO THE EAST OF THE HUDSON
VALLEY..WITH SOME POCKETS OF MODERATE TO HEAVY RAINFALL IN DUTCHESS
COUNTY AS WELL AS PORTIONS OF SOUTHERN VERMONT. THERE WERE WIDELY
SCATTERED LIGHT SHOWERS STILL AROUND MAINLY ACROSS THE MOHAWK VALLEY.
HOWEVER...ANOTHER LINE OF SHOWERS WERE DEVELOPING RIGHT AHEAD OF THE
COLD FRONT...LOCATED IN CENTRAL NEW YORK. THE HRRR AND HIRESWRF BOTH
HAVE THIS LINE OF SHOWERS COMING THROUGH. FOR ONCE...THESE MODELS
HAVE APPEARED TO DONE FAIRLY WELL WITH THE EVOLUTION OF THE RAINFALL
THUS FAR. THEREFORE...WILL LEAN WITH ITS SOLUTION OF BRINGING
ANOTHER LINE OF NUMEROUS SHOWERS OUR WAY THIS AFTERNOON. THIS LINE
LOOKS TO MOVE THROUGH BETWEEN ABOUT 100 PM (NORTHWEST) TO ABOUT 800
PM (SOUTHEAST). WINDS OFF THE DECK LOOK TO BACK TO THE SOUTHEAST
WILL WOULD HELP ENHANCED CONVERGENCE AND UPWARD MOTION WITH THE
FRONT.
INSTABILITY IS VERY LIMITED...GENERALLY UNDER 1000/J SO AT THIS
TIME...WE ARE FAIRLY CONFIDENT THERE WILL BE NO SEVERE OR EVEN
STRONG THUNDERSTORM ACTIVITY. ONE THING TO NOTE...THERE IS SOME
PRETTY LOW LEVEL WIND WITH THE LOWER WINDS SSE BECOMING WSW QUICKLY
AS ONE GOES THROUGH NEAR THE GROUND THROUGH ABOUT 5000 FEET. THERE
COULD BE SOME WEAK LOW LEVEL ROTATION BUT AGAIN WITH VERY LIMITED
INSTABILITY NOTHING ELSE IS EXPECTED...OTHER THAN PERHAPS A LITTLE
MORE HEAVY RAINFALL.
MAX TEMPS LOOK TO BE THE HELD IN THE LOW TO MID 70S TODAY. TEMPS
WILL ONLY REACH THE UPPER 60S ACROSS THE HIGHEST TERRAIN.
THE FRONT WILL CROSS DURING THE EARLY EVENING HOURS. THIS WILL BRING
AN END TO THE RAIN SHOWERS. SOME LINGERING SHOWERS ARE POSSIBLE
ACROSS NORTHERN AREAS TONIGHT AS THE UPPER TROUGH APPROACHES AND
PASSES JUST TO THE NORTH. WITH COOLER AIR STARTING TO MOVE IN BEHIND
THE COLD FRONT...MIN TEMPS WILL DROP INTO THE 50S OVERNIGHT AND
DEWPOINTS WILL FALL DURING THE OVERNIGHT HOURS.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE OHIO VALLEY FOR
THE ENTIRE SHORT TERM PERIOD. IT LOOKS TO BE MAINLY DRY ACROSS
THE REGION WITH COMFORTABLE HUMIDITY LEVELS AND BELOW NORMAL
TEMPERATURES. THE EXCEPTION TO THE DRY WEATHER WILL BE DURING THE
DAY ON WEDNESDAY ACROSS THE ADKS...WHERE COOL TEMPS ALOFT WILL
ALLOW FOR THE FORMATION OF SOME SCATTERED LIGHT RAIN SHOWERS.
MAX TEMPS ON WED AND THURSDAY WILL BE IN THE LOW TO MID 70S FOR
VALLEY AREAS /60 ACROSS THE HIGH TERRAIN. MIN TEMPS WILL GENERALLY
BE IN THE LOW 50S /40S FOR THE HIGH TERRAIN AND OUTLYING AREAS/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRY AND TRANQUIL WEATHER IS EXPECTED FOR THE PERIOD. RIDGING IS
EXPECTED TO DOMINATE AT THE SURFACE WITH HEIGHTS ALOFT GRADUALLY
RISING WITH RIDGING BUILDING IN ACROSS THE WESTERN ATLANTIC.
A WAVE OF LOW PRESSURE IS EXPECTED TO MOVE EASTWARD ALONG A STALLED
FRONTAL BOUNDARY ACROSS THE SOUTHEASTERN UNITED STATES. THE BOUNDARY
IS EXPECTED TO SHIFT NORTHWARD OVER THE WEEKEND. HOWEVER IT APPEARS
PRECIPITATION ASSOCIATED WITH THIS FEATURE SHOULD REMAIN TO OUR
SOUTH...SO LOOKING AT DRY WEATHER THROUGH THE WEEKEND INTO EARLY
NEXT WEEK.
SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS MAINLY IN THE MID
70S TO LOWER 80S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHOWERS AND SCATTERED THUNDERSTORMS WILL CONTINUE TO OVERSPREAD THE
AREA THIS MORNING WITH MVFR CONDITIONS DEVELOPING. DYNAMICS WITH
THIS SYSTEM ARE STRONG ENOUGH THAT AN AREA OF LOW PRESSURE HAS
FORMED OVER THE SAINT LAWRENCE RIVER VALLEY WITH A SECONDARY AREA OF
LOW PRESSURE OVER DELMARVA. BOTH LOWS WILL MOVE NORTHEASTWARD
EVENTUALLY CONSOLIDATED INTO ONE LOW OVER NEW ENGLAND LATE TONIGHT.
HAVE ADDRESSED THREAT FOR HEAVIER CONVECTION WITH A TEMPO GROUP WITH
IFR CONDITIONS. DO NOT HAVE THUNDERSTORMS SPECIFICALLY MENTIONED IN
TAFS AT TIME. CONVECTION WILL TAPER OFF LATE THIS AFTERNOON INTO THE
EVENING. CONDITIONS SHOULD IMPROVE TO VFR FOR A PERIOD THIS EVENING
INTO THE OVERNIGHT...HOWEVER A RETURN TO MVFR IS ANTICIPATED WITH
IFR POSSIBLE AT KGFL AND KPSF.
LIGHT SOUTHERLY WINDS WILL SHIFT TO THE WEST WITH THE PASSAGE OF THE
LOWS AND FRONTAL BOUNDARY.
OUTLOOK...
WED-SAT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES EXPECTED OVER THE NEXT FEW DAYS.
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A FRONTAL BOUNDARY IS
EXPECTED TODAY. RAINFALL AMOUNTS LOOK TO AVERAGE AROUND ONE HALF
INCH...LOCALLY OVER AN INCH WHERE HEAVIER SHOWERS OR
THUNDERSTORMS TAKE PLACE. THIS WILL BRING A WETTING RAIN TO THE
REGION.
RH VALUES WILL ONLY DROP TO 70 TO 80 PERCENT TODAY DUE TO CLOUDS AND
RAIN. THEY WILL BE NEAR 100 PERCENT TONIGHT AND DROP TO AROUND 40
TO 60 PERCENT TOMORROW AFTERNOON.
LARGE CANADIAN HIGH PRESSURE LOOKS TO TAKE CONTROL OF OUR WEATHER
WEDNESDAY THROUGH AT LEAST FRIDAY WITH DRY WEATHER.
&&
.HYDROLOGY...
AN APPROACHING FRONTAL BOUNDARY WILL BRING A ROUND OF RAIN SHOWERS
AND POSSIBLE THUNDERSTORMS TO THE REGION TODAY. PWAT VALUES WILL RISE
TO AROUND 1.50-1.75 INCHES INCHES AHEAD OF THE FRONTAL BOUNDARY.
WHILE ANY SHOWER OR THUNDERSTORM WILL BE CAPABLE OF HEAVY
DOWNPOURS...THE ATMOSPHERE IS NOT QUITE AS MOIST AS LATE LAST WEEK
WHEN SOME FLASH FLOODING OCCURRED ACROSS THE MID HUDSON VALLEY AND
NW CT. IN ADDITION...STRONG FLOW ALOFT SHOULD KEEP ANY SHOWERS OR
THUNDERSTORMS MOVING RATHER QUICKLY. AS A RESULT...FLASH FLOODING
IS NOT ANTICIPATED WITH THIS STORM SYSTEM. SOME MINOR RISES WILL
BE POSSIBLE ON AREA RIVERS AND STREAMS...ESPECIALLY ACROSS THOSE
AREAS THAT SAW HEAVIER RAIN LAST WEEK. THERE STILL COULD BE
PONDING ON ROADWAYS AND AREAS OF POOR DRAINAGE THROUGH TUESDAY
EVENING.
DRY WEATHER WILL RETURN BY LATE TONIGHT AND CONTINUE THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW RIVER AND STREAMS LEVELS TO
RECEDE ONCE MORE.
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/HWJIV
NEAR TERM...FRUGIS/SND/HWJIV
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
325 PM EDT TUE AUG 13 2013
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
SHORT RANGE MODELS CONTINUE TO SHOW A COLD FRONT...CURRENTLY ACROSS
TN... SAGGING ACROSS NORTH GA TONIGHT AND STALLING ACROSS CENTRAL GA
WEDNESDAY AFTERNOON. REGIONAL RADARS SHOW SCATTERED SHOWERS AND
THUNDERSTORMS BEGINNING TO DEVELOP ACROSS THE FORECAST AREA AS AN
UPPER DISTURBANCE APPROACHES FROM THE WEST. EXPECT A WEAK SURFACE
TROUGH TO HELP PROVIDE A FOCUS ACROSS NORTH GA THIS AFTERNOON AND
RADAR TRENDS SUPPORT THAT...WITH A SCATTERED LINE OF CONVECTION
DEVELOPING FROM WEST OF ROME...EASTWARD TO JASPER AND CLEVELAND.
EXPECT THIS ACTIVITY TO SAG SOUTHWARD THROUGH THE LATE AFTERNOON AND
EVENING HOURS. ADDITIONAL SCATTERED TO NUMEROUS CONVECTION IS
DEVELOPING ACROSS PARTS OF CENTRAL GA WHERE THE GREATER
INSTABILITIES AND DEEPER MOISTURE ARE POOLED. THE HRRR MODEL
CLUSTERS MOST OF THE CONVECTIVE ACTIVITY ACROSS THE CENTRAL ZONES...
FROM AREAS AROUND COLUMBUS TO MACON TO MILLEDGEVILLE AND SOUTHWARD
DURING THE LATE AFTERNOON AND EVENING HOURS. THUNDERSTORM ACTIVITY
MAY PERSIST THROUGH MID EVENING BEFORE DIMINISHING TO MAINLY
SHOWERS. SCATTERED SHOWERS MAY PERSIST OVERNIGHT ALONG AND AHEAD OF
THE COLD FRONT... BUT ANY THUNDERSTORM ACTIVITY SHOULD BE VERY
ISOLATED AT BEST OVERNIGHT. THE MAIN THUNDERSTORM THREAT THROUGH THE
EVENING WILL CONTINUE TO BE LOCALLY HEAVY RAIN AND POSSIBLE BRIEF
FLOODING. HOWEVER... WITH 2500-3000 CAPE... CANNOT RULE OUT A PULSE
STRONG STORM PRODUCING WIND GUSTS TO 40-45 MPH AND POSSIBLY SOME
SMALL HAIL. MODELS AGREE ON DRIER AIR SPREADING IN BEHIND THE FRONT
ACROSS NORTH GA BY EARLY WEDNESDAY... SO WILL SHOW THE GREATER RAIN
CHANCES ACROSS CENTRAL GA ON WEDNESDAY...AND MAINLY ALONG AND SOUTH
OF A LA GRANGE TO WARRENTON LINE...WITH ONLY A LOW CHANCE IN THE
ATLANTA METRO AREA FOR WEDNESDAY AFTERNOON. LOCALLY HEAVY RAIN WILL
REMAIN A THREAT ACROSS CENTRAL GA WEDNESDAY AFTERNOON AS THE FRONT
PROVIDES A FOCUS FOR TRAINING CONVECTION. MODELS SHOW GENERALLY ONE
QUARTER TO ONE HALF INCH FROM COLUMBUS TO MACON AND SOUTHWARD ON
WEDNESDAY... BUT ISOLATED HIGHER AMOUNTS OF 1 TO 3 INCHES ARE
POSSIBLE. ALTHOUGH CANNOT RULE OUT A PULSE STRONG TO SEVERE STORM
ALONG OR SOUTH OF THE FRONT WEDNESDAY AFTERNOON... NOT EXPECTING
ANYTHING WIDESPREAD AND THE GREATER STRONG STORM THREAT SHOULD BE
JUST SOUTH OF THE FORECAST AREA WEDNESDAY AFTERNOON AND EVENING.
OTHERWISE... AS FOR TEMPS A MODEL BLEND THROUGH THE SHORT TERM
LOOKED REASONABLE.
39
.LONG TERM /THURSDAY THROUGH TUESDAY/...
GUIDANCE CONTINUES TO POINT TO A WET EXTENDED PERIOD. AS THE FRONT
SAGS SOUTH OF THE AREA TROUGH THE SHORT TERM...SURFACE HIGH UNDER
CONFLUENT FLOW ALOFT WILL SLIP EAST AND ACROSS THE APPALACHIANS IN
A HYBRID DAMMING EVENT. THE QUESTION WILL BE HOW MUCH GULF
MOISTURE WILL INTERACT WITH THE DAMMING. FOR THURSDAY...WITH THE
STALLED FRONT AND ONSET OF HYBRID CAD...HPC AND SYNOPTIC MODELS
KEEP THE BEST PRECIP ACROSS CENTRAL GEORGIA...WITH A GOOD INCH OF
BASIN-AVERAGE QPF DURING THE DAY. THIS TREND CONTINUES INTO
FRIDAY. BESIDES THE PRECIP HOWEVER...THE BIGGEST SENSIBLE IMPACT
WILL BE TEMPS. CURRENT HIGH TEMPS FOR THURSDAY THROUGH SATURDAY DO
NOT BRING NORTH GEORGIA OUT OF THE 70S...AND REALLY ONLY INTO THE
MID 80S IN SOUTHERN ZONES. POSSIBLY A SLIGHT WARMING TREND BY A
DEGREE OR SO ON SUNDAY BUT THIS REMAINS TO BE SEEN. THESE FORECAST
MAX TEMPS ARE A GOOD 10 DEGREES COOLER THAN SEASONAL NORMALS...
THE KIND OF IMPACTS NORMALLY SEEN WITH CLASSICAL CAD RATHER THAN
HYBRID CAD.
00Z ECMWF CONTINUES TO TAKE THE TROPICAL WAVE /CURRENTLY IN THE
CARIBBEAN/ FURTHER WEST TOWARD THE YUCATAN...WHILE GFS AND
CANADIAN BRING IT INTO THE GULF AND CLOSE TO THE COAST FRIDAY
NIGHT. FOR WHAT ITS WORTH...THE CANADIAN IS STRONGER AND FURTHER
WEST WITH THE SURFACE LOW THAN THE GFS...WHICH WOULD POSSIBLY
INDICATE SEVERE POTENTIAL ON SATURDAY...BUT IT IS A BIT OF AN
OUTLIER THERE. ECMWF IS DRIEST WHILE GFS/CMC ARE WETTER
SOLUTIONS. HPC NOT GOING NEARLY AS HIGH AS THE GFS BUT EVEN
SO...WITH THE PROLONGED WET PERIOD ACROSS ESPECIALLY CENTRAL
GEORGIA FROM THE SHORT TERM FRONT...THERE IS SOME CONCERN ABOUT
THE RAINFALL PILING UP. HAVE NOT DONE A COMPLETE DIAGNOSIS TO
DETERMINE IF THE THURSDAY-FRIDAY RAIN WOULD QUALIFY AS A PRE
/PREDECESSOR RAINFALL EVENT/ BUT IN ANY CASE THE 7-DAY QPF TOTAL
FROM HPC ARE UPWARDS OF 6 INCHES ACROSS PORTIONS OF CENTRAL
GEORGIA. THIS BEING BASIN-AVERAGE...IMPLYING THAT SOME AREAS
COULD GET SUBSTANTIALLY MORE /AND OF COURSE SOME AREAS
SUBSTANTIALLY LESS/. ALL INTERESTS SHOULD STAY TUNED TO LATEST
FORECASTS AS THIS IS REFINED OVER THE NEXT FEW DAYS.
SO OVERALL...REALLY MADE ONLY MINOR CHANGES TO PREVIOUS EXTENDED
FORECAST. REFINED AND ADDED SOME DETAIL TO DAYS 4 AND 5 ESPECIALLY
WITH TEMPS WINDS AND DEWPOINTS /VERY LITTLE IF ANY CHANGE TO
POPS/ AND MADE SOME MINOR ADJUSTMENTS TO HIGH TEMPS THROUGH THE
REST OF THE PERIOD TO REFLECT THE PROLONGED COOL SPELL.
TDP
&&
.AVIATION...
18Z UPDATE...
VFR CIGS WILL PERSIST THROUGH THE TAF PERIOD. WRF AND HRRR MODELS
SHOW SCT CONVECTION BRUSHING ATL AROUND 21-23Z TODAY... SO WILL SHOW
TEMPO -TSRA AT THIS TIME. A COLD FRONT PUSHES INTO NORTH GA TONIGHT
AND SPREADS SOME DRIER AIR SOUTHWARD BY WED MORN. THIS SHOULD HINDER
ANY THREAT OF LOW CIGS AT ATL BY EARLY WED MORN. EXPECT A WNW WIND
AROUND 10G15KTS THIS AFTERNOON TO BECOME MORE NW AND DIMINISH TO
AROUND 6-8KTS BY 03Z... THEN NNW WINDS AROUND 8-10KTS BY 15Z WED.
THE FRONT MOVES SOUTH OF ATL EARLY WED WITH A DRIER NW FLOW...SO NO
MENTION OF TSRA FOR ATLANTA AREA ON WED.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TEMPO -TSRA THIS AFTERNOON. HIGH ON ALL OTHER
ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 88 68 78 / 50 40 20 30
ATLANTA 70 86 69 79 / 50 30 20 50
BLAIRSVILLE 64 81 64 76 / 50 20 20 30
CARTERSVILLE 68 86 64 82 / 50 20 20 30
COLUMBUS 73 87 71 84 / 40 60 40 80
GAINESVILLE 69 85 68 76 / 50 20 20 30
MACON 72 89 71 82 / 40 60 50 80
ROME 68 89 63 83 / 50 20 10 30
PEACHTREE CITY 70 86 66 79 / 40 40 20 50
VIDALIA 74 88 71 84 / 30 60 60 80
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...39
LONG TERM....TDP
AVIATION...39
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
150 PM EDT TUE AUG 13 2013
.MORNING UPDATE...
/ISSUED AT 1107 AM EDT TUE AUG 13 2013/
LATEST SURFACE ANALYSIS SHOWS A WEAK TROUGH ACROSS NORTH GA WITH A
COLD FRONT ACROSS WEST TN AND INTO THE OHIO VALLEY. THE UPPER LEVELS
SHOW WEAK DISTURBANCES APPROACHING FROM THE WEST. CONVECTIVE MODELS
INDICATE POSSIBLY TWO ROUNDS OF CONVECTION THIS AFTERNOON AND
EVENING...THE FIRST POSSIBLY FOCUSED ALONG THE SURFACE TROUGH TO THE
NORTH AND THIS ACTIVITY SAGS SOUTH INTO CENTRAL GA DURING THE MID TO
LATE AFTERNOON HOURS. ANOTHER ROUND PUSHES INTO NORTH GA AHEAD OF
THE COLD FRONT LATE THIS AFTERNOON-EARLY EVENING AND ALSO SAGS SOUTH
OVERNIGHT... ALTHO THIS ACTIVITY WILL WEAKEN TO MAINLY JUST SHOWERS
BY LATE EVENING. HAVE UPDATED ZONES TO TWEAK LIKELY POPS MORE INTO
WEST CENTRAL ZONES THIS AFTERNOON AND HELD ONTO SLIGHTLY HIGHER POPS
NORTH THROUGH THE EVENING HOURS. MORNING SOUNDING SUGGEST LOCALLY
HEAVY RAIN WILL CONTINUE TO BE THE MAIN THREAT WITH SOUNDING SHOWING
NEAR 2 INCH PW`S. FREQUENT LIGHTNING...WIND GUSTS TO 40 MPH... AND
SMALL HAIL WILL ALSO BE POSSIBLE THROUGH MID EVENING WITH THE
STRONGER STORMS. /39
.PREVIOUS DISCUSSIONS /ISSUED AT 440 AM EDT TUE AUG 13 2013/...
SHORT TERM /TODAY THROUGH WEDNESDAY/...
VARIOUS LEVELS OF CLOUDS OVER GA THIS MORNING DUE TO PREVIOUS TSTMS
MONDAY EVENING. LOW STRATUS IS DEVELOPING OVER WET GROUND AT THIS
TIME FROM RAINFALL IN THE PAST 24 HOURS. A COLD FRONT WAS MOVING
SOUTHEAST THROUGH KY AND AR WHILE A NEAR ZONAL FLOW PREVAILED OVER
GA. EXPECT ENOUGH DIURNAL HEATING AND SYNOPTIC SCALE FORCING IN
ADVANCE OF THE COLD FRONT TODAY TO LIFT THE LOW STRATUS AND THEN
DOMINATE WITH A BKN CU FIELD. WITH SO MUCH TROPICAL MOISTURE
AVAILABLE...PWS NEAR 2 INCHES...EXPECT SCATTERED TSTMS TO DEVELOP AS
EARLY AS 1000 AM EDT OVER NORTH GA IN ADVANCE OF THE APPROACHING
COLD FRONT THROUGH THE TN VALLEY. THE REMAINDER OF NORTH GA
INCLUDING THE ATL AREA WILL BE AROUND NOON OR LATER. THE FRONT
SHOULD ENTER NORTHWEST GA AROUND 800 PM EDT AND CONTINUE MOVING INTO
CENTRAL GA BY WEDNESDAY MORNING. THE SCATTERED TO NUMEROUS TSTMS
THIS AFTERNOON SHOULD DIMINISH TO ISOLATED OVERNIGHT AS THE AIRMASS
OVER GA GRADUALLY STABILIZES FROM PRECIPITATION AND EVAPORATIONAL
COOLING. THE NEARLY STATIONARY FRONT OVER CENTRAL AND SOUTH GA
COMBINED WITH AN APPROACHING UPPER LEVEL DISTURBANCE WILL INITIATE
NUMEROUS TSTMS OVER CENTRAL GA BY WEDNESDAY AFTERNOON AND EVENING.
ISOLATED TO SCATTERED TSTMS CAN BE EXPECTED OVER NORTH GA. FAVORED
AND INCREASED THE WETTER NAM SOLUTION DURING THE FORECAST PERIOD.
TEMPS WERE A MET/MAV MOS GUIDANCE BLEND.
16
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
GFS AND EUROPEAN MODELS INDICATING AN INCREASINGLY WET PERIOD.
A STATIONARY FRONT WILL LIE ACROSS THE CENTRAL TO S GA AREA TO START
THE LONG TERM WITH AN UPPER LEVEL TROUGH EXPECTED TO DEVELOP IN THE
THURSDAY TO FRIDAY TIME FRAME OVER THE MID U.S AND DRIFT E. THIS
WILL ALLOW FOR MOIST SOUTHERLY FLOW TO DEVELOP ALONG WITH A CAD TYPE
AIRMASS OVER THE NORTH. 50-80 PERCENT POPS CAN BE EXPECTED FOR MUCH
OF THE AREA WEDNESDAY NIGHT THROUGH MONDAY AND HAVE LEANED HARD ON
HPC GUIDANCE WITH HIGHER POPS AND LOWER DAYTIME TEMPERATURES. THE
UPPER TROUGH WILL WEAKEN ON MONDAY WITH THE GFS AND EUROPEAN
DIFFERING ON HOW MUCH IT WEAKENS INTO TUESDAY.
SIGNIFICANT RAINFALL CAN BE EXPECTED DURING THIS PERIOD FAVORING
CENTRAL GA MORE THAN N GA. THE GFS IS INDICATING A HEAVY PRECIP
BULLSEYE AND IS MOST LIKELY OVERDONE COMPARED TO THE MORE REASONABLE
LOOKING EUROPEAN.
HIGH TEMPERATURES WILL BE ON THE ORDER OF 5-10 DEGREES BELOW NORMAL.
LOW TEMPERATURES WILL BE CLOSE TO SLIGHTLY BELOW NORMAL FOR MUCH OF
THE PERIOD.
BDL
&&
.AVIATION...
18Z UPDATE...
VFR CIGS WILL PERSIST THROUGH THE TAF PERIOD. WRF AND HRRR MODELS
SHOW SCT CONVECTION BRUSHING ATL AROUND 21-23Z TODAY... SO WILL SHOW
TEMPO -TSRA AT THIS TIME. A COLD FRONT PUSHES INTO NORTH GA TONIGHT
AND SPREADS SOME DRIER AIR SOUTHWARD BY WED MORN. THIS SHOULD HINDER
ANY THREAT OF LOW CIGS AT ATL BY EARLY WED MORN. EXPECT A WNW WIND
AROUND 10G15KTS THIS AFTERNOON TO BECOME MORE NW AND DIMINISH TO
AROUND 6-8KTS BY 03Z... THEN NNW WINDS AROUND 8-10KTS BY 15Z WED.
THE FRONT MOVES SOUTH OF ATL EARLY WED WITH A DRIER NW FLOW...SO NO
MENTION OF TSRA FOR ATLANTA AREA ON WED.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TEMPO -TSRA THIS AFTERNOON. HIGH ON ALL OTHER
ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 69 87 69 / 50 40 50 50
ATLANTA 87 70 85 70 / 60 40 50 40
BLAIRSVILLE 82 65 82 64 / 70 30 20 40
CARTERSVILLE 87 68 88 66 / 90 50 20 30
COLUMBUS 91 73 88 71 / 70 50 60 50
GAINESVILLE 87 70 85 69 / 60 50 40 40
MACON 91 72 88 71 / 60 30 60 50
ROME 88 68 88 65 / 90 40 20 20
PEACHTREE CITY 87 69 86 70 / 60 40 60 40
VIDALIA 93 74 90 72 / 50 30 60 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...16/39
LONG TERM....BDL/25
AVIATION...39
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1228 PM CDT TUE AUG 13 2013
.DISCUSSION...
1050 AM CDT
FOR MORNING UPDATE...
NO SIGNIFICANT CHANGES TO NEAR TERM FORECAST THIS MORNING. ONLY
MINOR TWEAKS TO HOURLY TEMP/SKY COVER GRIDS BASED ON CURRENT OBS AND
SATELLITE TRENDS.
SPRAWLING CANADIAN SURFACE HIGH PRESSURE CONTINUES TO BUILD
SOUTHEAST FROM THE LAKE WINNIPEG AREA OF SOUTHERN MANITOBA LATE THIS
MORNING...WITH BREEZY NORTH-NORTHEAST SURFACE WINDS AHEAD OF THE
ADVANCING ANTICYCLONE BRINGING COOLER AND DRIER ALMOST EARLY-AUTUMN
LIKE AIR TO THE FORECAST AREA. IN FACT...THE COOL AIR ALOFT...WITH
+5C SAMPLED AT 850 MB IN THE GREEN BAY WISC 12Z RAOB...HAS LED TO
DEVELOPMENT OF LAKE EFFECT STRATOCU ACROSS LAKE MICHIGAN. THIS LAKE
INDUCED CLOUD COVER WAS SPREADING INLAND INTO THE CHICAGO METRO AREA
DOWNWIND OF THE LAKE. ASSESSMENT OF THE MORNING RAOB DATA AND MODEL
LOW-LEVEL THERMAL FIELDS CONTINUES TO INDICATE A RATHER COOL DAY FOR
MID-AUGUST...WITH HIGHS RANGING FROM PERHAPS THE UPPER 60S ALONG THE
LAKE MICHIGAN SHORE...TO THE LOW-MID 70S IN THE WARMEST INLAND
REACHES SUCH AS DIXON/PONTIAC. DEW POINT TEMPS IN THE MID-UPPER 40S
WILL MAKE FOR DRY CONDITIONS THIS AFTERNOON AS WELL...AS WINDS BEGIN
TO DIMINISH WITH THE GRADIENT GRADUALLY WEAKENING WITH THE APPROACH
OF THE HIGH PRESSURE CENTER.
RATZER
//PREV DISCUSSION...
327 AM CDT
WITH EXPANSIVE SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTHWEST
AND THEN ESTABLISHING ITSELF OVER THE GREAT LAKES REGION THROUGH THE
WEEKEND...THERE ARE NO REAL WEATHER CONCERNS FOR THE AREA.
HOWEVER...AN UNSEASONABLY COOL AIR MASS IS PLUNGING SOUTH DOWN LAKE
MICHIGAN BEHIND A SECONDARY COLD FRONT AND SHARP TROUGH AXIS SEEN
WELL ON WATER VAPOR IMAGERY EARLY THIS MORNING. THIS WILL QUICKLY
TRANSPORT THE MID SINGLE DIGIT 850 MB TEMPS OVER ONTARIO ON THE 00Z
RAOB TO OUR AREA BY THIS AFTERNOON...WHICH WILL MAKE FOR MORE
FALL-LIKE THAN SUMMER-LIKE HIGH TEMPERATURES PRIMARILY IN THE LOWER
70S...WITH A SCATTERING OF MID 70S READINGS IN THE FAR SOUTH AND
WEST. DESPITE A VERY DRY AIRMASS...STEEPENING LOW LEVEL LAPSE RATES
AND NEAR SATURATION AT ABOUT 800 MB WILL LIKELY RESULT IN A
BLOSSOMING STRATOCU DECK BY MID TO LATE MORNING THAT WILL GRADUALLY
DISSIPATE THROUGH THE EVENING.
IN ADDITION...FORECAST SOUNDINGS INDICATE FAVORABLE PROFILES FOR
GENERATION OF LAKE EFFECT CLOUDS WHICH ARE EXPECTED TO BE CARRIED ON
STRONG NORTHERLY FLOW INTO NEAR LAKE AREAS OF NORTHWEST
INDIANA...WHICH WILL LIMIT HIGHS THERE TO THE UPPER 60S. NORTHEAST
ILLINOIS MAY SEE A BIT OF A SHADOWING EFFECT TO KEEP CLOUD COVER AT
A MINIMUM FOR A TIME...BUT THE LAKESHORE WILL STILL STRUGGLE TO
REACH 70 DEGREES. ADDING TO THE FALL-LIKE FEEL WILL BE GUSTY
NORTH-NORTHEAST WINDS...STRONGEST NEAR THE LAKEFRONT...THANKS TO
A TIGHT PRESSURE GRADIENT AND THE UNSTABLE CONDITIONS OVER THE
LAKE. THOSE THAT BRAVE THE COOL CONDITIONS TO HEAD TO THE BEACH
WILL BE GREETED BY HIGH WAVES AND DANGEROUS CURRENTS...SO SWIMMING
IS STRONGLY DISCOURAGED.
TONIGHT...WINDS WILL QUICKLY DIMINISH AS THE HIGH BUILDS IN AND
SKIES SHOULD CLEAR FOR MOST AREAS AFTER ANY LINGERING EVENING
STRATOCU. THIS WILL SET THE STAGE FOR VERY CHILLY CONDITIONS IN
RURAL AND OUTLYING SUBURBAN AREAS WHERE UPPER 40S ARE EXPECTED AND
EVEN A FEW MID 40S ARE POSSIBLE. THE CHICAGO HEAT ISLAND WILL DROP
TO NEAR 60 DEGREES. THE EXCEPTION TO THE ABOVE WILL BE THE
NORTHWEST INDIANA AND POSSIBLY FAR EAST AND SOUTHEAST COOK COUNTY
LAKEFRONT...WHERE FAVORABLE LAKE EFFECT CONDITIONS WILL CONTINUE
TO EXIST AND RESULTANT CLOUD COVER WILL KEEP TEMPERATURES MILDER.
CONSIDERED PUTTING IN A SLIGHT CHANCE POP FOR LAKE EFFECT SHRA BUT
HELD OFF AND WILL ALLOW THE DAY SHIFT TO ASSESS...AS THE AIR MASS
MOVING OVER THE LAKE IS VERY DRY.
ON WEDNESDAY AND BEYOND...INVERSION LEVELS WILL DROP AS MID LEVEL
HEIGHTS RISE...SO ANY LAKE EFFECT CLOUDS WILL LIKELY DIMINISH
EARLY...BUT EXPECT TO SEE BLOSSOMING CUMULUS AGAIN BY LATE MORNING.
850 MB TEMPERATURES WILL BE CLOSE TO TODAY...BUT 925 MB TEMPS WILL
RISE TO SUPPORT A FEW DEGREE RISE IN HIGH TEMPERATURES. THE
CONTINUED GRADUAL DEPARTURE OF THE DEEP TROUGH OVER EASTERN CANADA
AND THE GREAT LAKES WILL RESULT IN WARMING THERMAL PROFILES ON
THURSDAY...SO AFTER ANOTHER CLEAR AND CHILLY NIGHT...SOME LOCATIONS
MAY TAG 80 DEGREES. THE SLOW WARMING TREND WILL THEN CONTINUE
THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH HIGHS IN THE MID 80S
OR EVEN WARMER POSSIBLY BY MONDAY. THE SOUTHEASTERN CWA COULD SEE
ENOUGH MOISTURE RETURN BEHIND HIGH PRESSURE FINALLY SHIFTING TO THE
EAST FOR A LIMITED THREAT FOR TSRA BY MONDAY OR POTENTIALLY AS EARLY
AS SUNDAY...BUT OTHERWISE THE DRY PATTERN MOST OF THE AREA HAS BEEN
IN SINCE THE BEGINNING OF JULY WILL CONTINUE.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* STRONG/GUSTY NORTH/NORTHEAST WINDS THROUGH EARLY THIS EVENING.
CMS
//DISCUSSION...UPDATED 18Z...
ONLY FORECAST CONCERN THIS PERIOD ARE WINDS. HIGH PRESSURE ACROSS
THE NORTHERN PLAINS WILL SPREAD SOUTHEAST ACROSS THE AREA
OVERNIGHT INTO WEDNESDAY. GUSTY NORTHEASTERLY WINDS WILL CONTINUE
THIS AFTERNOON BUT BEGIN TO SLOWLY DIMINISH. POSSIBLE GUSTS WILL
DIMINISH PRIOR TO CURRENT END TIME...POSSIBLY AS EARLY AS 22Z-
23Z...ESPECIALLY ACROSS NORTHWEST IL. AS THE HIGH APPROACHES THIS
EVENING...WINDS MAY TURN NORTHWESTERLY OR EVEN WESTERLY...BUT AT
THAT TIME SPEEDS WILL BE WELL UNDER 10 KTS. WINDS WILL THEN BECOME
LIGHT AND VARIABLE OR CALM OVERNIGHT. LIGHT NORTH/NORTHEAST WINDS
EXPECTED WEDNESDAY MORNING WITH A LAKE BREEZE TURNING WINDS MORE
EASTERLY WEDNESDAY AFTERNOON. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR WINDS THIS AFTERNOON...MEDIUM FOR THE REST OF THE
PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH MONDAY...VFR.
MDB
&&
.MARINE...
300 AM CDT
A SERIES OF COLD FRONTS HAS NOW PUSHED SOUTH OF LAKE MICHIGAN WITH A
FAIRLY TIGHT PRESSURE GRADIENT POSITIONED ACROSS THE LAKE WITH LOW
PRESSURE TO THE EAST OVER EASTERN ONTARIO AND A STRONG HIGH PRESSURE
SYSTEM TO THE WEST FROM MANITOBA ACROSS THE DAKOTAS. NORTH TO
NORTHEAST WINDS HAVE INCREASED ACROSS THE LAKE AND WILL REMAIN
STRONG THROUGH LATE AFTERNOON AT WHICH POINT SPEEDS WILL BEGIN TO
GRADUALLY EASE AS THE PRESSURE GRADIENT SLACKENS. WESTERN AND
NORTHERN SECTIONS OF THE LAKE WILL SEE WINDS DIMINISHING FIRST AS
THE GRADIENT WILL BE WEAKENING FROM NORTHWEST TO SOUTHEAST. WAVES
WILL CONTINUE TO BUILD THIS MORNING WITH THE LONG FETCH DIRECTING
THEM AT THE SOUTHERN SHORELINES. HAVE BUMPED WAVES UP TO 5 TO 8 FT
WITH OCCASIONAL 12 FT FOR THE SOUTHERN PARTS OF THE LAKE WITH WELL
EXPOSED BUOYS NEAR THE END OF THE DEVELOPING FETCH ALREADY SHOWING
WAVES IN THE 4 TO 6 FT RANGE...WITH A FEW PEAKS CLOSER TO 7 FT. WILL
CONTINUE WITH THE SMALL CRAFT ADVISORY AS-IS. THE HIGH WILL MOVE
SOUTHWARD AND SETTLE INTO ILLINOIS INTO WEDNESDAY AND THEN GRADUALLY
SPREAD EASTWARD ACROSS THE OHIO VALLEY THROUGH THE END OF THE WEEK.
NORTHERLY WINDS WILL LIKELY TURN ONSHORE WEDNESDAY WITH THE WEAK
PRESSURE GRADIENT IN PLACE BEFORE SHIFTING TO SOUTHERLY ACROSS MOST
OF THE LAKE WEDNESDAY NIGHT AS THE HIGH SHIFTS. SOUTHWEST TO WEST
WINDS ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK BUT ONSHORE
FLOW WILL LIKELY SET UP ACROSS SOUTHERN PARTS OF THE LAKE WHERE THE
PRESSURE GRADIENT WILL REMAIN WEAK INTO THE WEEKEND.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM WEDNESDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 AM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1148 AM CDT Tue Aug 13 2013
.DISCUSSION...
ISSUED 950 AM CDT Tue Aug 13 2013
Large shield of cirrus clouds continues to push eastward this
morning, but has been showing some thinning as of late. Have had
quite a bit of stratus over the southeast CWA which is a bit
stubborn to erode, and a narrow band has also been quickly
dropping southwest toward the I-74 corridor as cooler and drier
air works its way toward our area. The diurnal cumulus should
start forming over the next couple hours, but latest CU-rule off
the RAP model diminishes this from north to south as the drier air
aloft mixes downward, so sunshine should be on the increase during
the afternoon.
Have made the usual minor hourly temperature adjustments for
today, which generally did not impact the high temperature
forecasts. Also refreshed the zone forecasts to remove mention of
morning fog in the eastern CWA, although little change was needed
otherwise.
Geelhart
&&
.AVIATION...
ISSUED 1147 AM CDT Tue Aug 13 2013
Narrow band of MVFR ceilings continues to drop southwest as drier
air moves into central Illinois. Will see these continue for
another hour or two from KSPI-KDEC-KCMI, with diurnal cumulus
above 3000 feet forming afterward. Greatest question with ceilings
will be at KCMI, where lake-effect clouds continue to stream
southward toward the area. Clouds will fade mid to late afternoon
in most areas. Mainly clear skies expected tonight into Wednesday
morning, as high pressure settles into the mid-Mississippi Valley.
Northeast winds will gradually trend more northerly Wednesday
morning with the arrival of the high.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 253 AM CDT Tue Aug 13 2013
SHORT TERM...Today through Thursday
07z/2am surface analysis shows cold front settling southward
toward the Ohio River, with bulk of remaining convection now well
to the south across far southern Indiana into Kentucky. Despite
frontal passage and light northerly flow, air mass remains rather
humid across central Illinois. Surface dew points are still in the
middle to upper 60s across most of the area, with drier upper 50s
beginning to filter into the far north around Galesburg. Due to
mostly clear skies and light winds, this lingering low- level
moisture is producing some patchy fog around the area. Will
include fog mention in the forecast this morning, mainly for
locations south of I-72 where moisture will linger longest. After
any early morning fog dissipates, mostly sunny and cool weather
will be the rule today. Secondary cold front will allow very cool
air mass to pour southward into Illinois today, with 850mb temps
expected to drop into the 8 to 10C range. Numeric guidance is
suggesting highs only in the lower to middle 70s: however, based
on upstream readings yesterday afternoon and strength of mid-
August sun, think this is too cool. Will go several degrees above
guidance, with highs ranging from the middle 70s far north, to the
lower 80s along and south of I-70.
Clear skies and light winds will allow excellent radiational
cooling conditions to develop tonight, resulting in chilly
overnight lows in the upper 40s and lower 50s. With high pressure
remaining overhead, the cool/dry weather will continue on
Wednesday and Thursday as well, with highs in the middle to upper
70s and lows mainly in the 50s.
LONG TERM...Friday through Monday
Short-wave currently evident on water vapor imagery over Oregon
will track up and over the western CONUS ridge and into the
Midwest by the end of the week. This feature may trigger scattered
showers/thunder across Iowa and Nebraska Thursday night; however,
by the time it arrives in the drier air mass across Illinois, am
expecting only a slight increase in cloud cover on Friday. The
wave will act to amplify the existing long-wave trough in place
across the eastern CONUS this weekend into early next week. 00z
Aug 13 models continue to suggest the amplifying trough will
eventually lead to the development of an inverted surface trough
across the Ohio River Valley Sunday/Monday. This is the second
straight day models have latched onto this solution, so confidence
is growing that disturbed weather may develop to the E/SE early
next week. GFS/ECMWF spread a few showers into east-
central/southeast Illinois Sunday and Monday, however GEM tends to
keep precip a bit further east across Indiana. Will increase cloud
cover and carry a slight chance POP east of I-57 accordingly. Air
mass will slowly moderate through the period, with high
temperatures climbing back into the lower to middle 80s by Sunday.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
328 PM CDT Tue Aug 13 2013
.SHORT TERM...(This Evening through Wednesday)
Issued at 328 PM CDT TUE AUG 13 2013
Upper trough remains over the Great Lakes with a shortwave trough
extending southwestward into eastern Nebraska. This shortwave along
with a well defined MCV in southern Nebraska helped sustain a
cluster of showers and thunderstorms into the far northwest corner
of the CWA this afternoon. However...a drier and more stable
atmosphere over most of the CWA has aided a weakening trend to the
convection and expect any sustained or additional development to
occur in the western or far southern CWA until early evening. At
that time...feel majority of convection...now occurring in central
KS will have advanced further south of the vicinity with the outflow
boundary...similar to the HRRR model. Will therefore carry a dry
forecast for the overnight. Skies may become mostly clear tonight which
would support the possibility of some patchy fog. However...feel the
potential for more high clouds to advance into the area from the
northwest is high enough to negate mentioning fog for now. The dry
air and breaks in the clouds should help lows fall into the lower
60s.
On Wednesday...will maintain a dry CST as the deeper moisture and
axis of higher instability are pushed more to the west of the CWA.
Any convection through the day should remain to the west and north
of the CWA. High temperatures Wednesday will be similar
today...except slightly warmer in the north central with readings in
the lower 80s.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 328 PM CDT TUE AUG 13 2013
For Wednesday night through Friday, the models have trended more
along the lines of the NAM with keeping much of the cooler and
dryer air to the northeast of the forecast area. On top of that
instead of a distinct shortwave trough moving through the
northwest flow Thursday night, models have trended towards
bringing several vort maximum through the flow late Wednesday
night through Friday. Because of this have trended min temps
warmer expecting more cloud cover and higher dewpoint temps
through the night. Will also carry a 20 to 30 percent chance pops
through the period. Forecast soundings with the higher dewpoints
show much less inhibition to convection with lower LCL heights.
because of this it is difficult to rule out precip chances with
the expected vort energy moving overhead. The airmass in general
does not change much from today. Therefore expect temps to be
relatively persistent with highs around 80 and lows in the lower
to mid 60s.
Saturday into Monday is expected to be dry with a gradual warming
trend as mid level ridging moves in from the west and insolation
increases. Uncertainty remains in the forecast for next week as
the ECMWF has shown little consistency from run to run over the
last 48 hrs. Think that there will be a small chance for precip
Monday night and Tuesday as the GFS continues to bring a shortwave
trough across the plains. However confidence is not high since the
ECMWF goes back and forth between cutting off an upper low and an
open shortwave.
&&
.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1239 PM CDT TUE AUG 13 2013
Still expect VFR conditions to persist through the forecast as
convection expected to remain west and south of the terminals
through the period. Could see possible fog tonight...but forecast
for high clouds in the area makes confidence in fog potential
low...so will therefore not introduce into at this time. east to
northeast winds will persist generally under 10 kts...but should
slowly veer beyond 12z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...63
LONG TERM...Wolters
AVIATION...63
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
1243 PM CDT Tue Aug 13 2013
.UPDATE...
Issued at 724 AM CDT TUE AUG 13 2013
The thunderstorm complex over central Nebraska continues to build
toward the south southeast this morning. In the past hour, a
segment of this complex began to forward propagate with more of a
southeasterly direction. Instability is limited but does exist
along the highway 81 corridor, and recent RAP runs suggest that it
may increase to around 1000 J/Kg by mid morning. This would
suggest at least some potential for the system to maintain itself
into parts of north central Kansas. Have increased precip chances
to around 40 percent, but still see potential for the complex to
weaken, remain west of the forecast area, or even fall apart
before getting very far into Kansas. Will watch closely as it
evolves now that the sun has risen and instability may or may not
increase.
Barjenbruch
&&
.SHORT TERM...(Today and Tonight)
Issued at 324 AM CDT TUE AUG 13 2013
A ridge of surface high pressure had worked its way into northern
Kansas early this morning, bringing with it a rather stable
airmass. While yet another short wave trough was moving east across
southern Kansas this morning, thunderstorm activity has been confined
south of the forecast area. Between 2 and 4 AM, the thunderstorm
complex has attempted to make a run to the northeast as it pushed
out weak outflow, and has come close to Dickinson and Morris
counties, but the airmass just seems to increase in stability to the
north and the forecast area has remained dry thus far. Another short
wave trough of interest, well defined in water vapor imagery, was
diving south out of the Dakotas and has aided in development of a
thunderstorm complex over north central Nebraska.
This morning, there is still some small chance for the complex over
southern Kansas to send a few storms into the far southern parts of
the forecast area, and have maintained small chances for
thunderstorms in these areas accordingly. This potential may even
linger into the early afternoon hours as the center of the short
wave passes over eastern Kansas. The activity over Nebraska is
forecast to track generally to the south with the bulk of convection
favored on the western flank where it has greater instability to
work with. This should keep this system west of the forecast area,
but included a slight chance for precip generally near and west of
Highway 81 in case it should clip the area. Temperatures will be
similar to, or even a bit cooler than Monday with highs in the lower
80s. Kept the forecast for tonight dry as the surface high would
seem to maintain a hold on the area with a stable airmass, and the
stronger deep forcing and upper support looks to remain south and
west of the forecast area.
Barjenbruch
.LONG TERM...(Wednesday through Monday)
Issued at 324 AM CDT TUE AUG 13 2013
On Wednesday, expansive area of surface high pressure centered
over the Mississippi Valley begins to shift eastward leaving
another dry and pleasant day for the area. Edged high temperatures
during the afternoon into the lower 80s with weak low level winds
and peaks of sunshine expected by the late afternoon period.
Focus returns to the northwest flow aloft on Thursday as another
wave is progged to deepen as it enters the northern plains and dives
southeast. The recent runs of the NAM, GFS, and ECWMF have varying
timing and intensity differences with the GFS being the most
amplified of the group. Almost all solutions have agreed on slight
chances of sct thunderstorms developing ahead of the trough on
Thursday afternoon over north central KS. Otherwise was not
confident to increase rain chances Thursday evening as the main
piece of energy may center just north or east of the area. Continued
the trend from the afternoon package by assuming increasing cloud
cover could leave highs Thursday near the 80 degree mark. Depending
on timing with the main upper level system could still see some
lingering showers and thunderstorms Friday afternoon especially over
east central and northeast portions of KS. Models are beginning to
trend subsidence filling in behind the wave which would bring dry
conditions over north central areas. Will see if this trend
continues in upcoming days.
Looking at the extended period, the weekend continues to look dry
and pleasantly warm as the upper ridge builds into the plains
region. With the weak flow pattern in place, highs in the low 80s
and lows near 60 degrees still appear to be reasonable. Another
shortwave trough entering over the Pacific Northwest suppresses the
ridge as it shifts into the plains region as we head into Monday.
Continued with a dry forecast at this time as low confidence
exists in timing and how deep the wave is progged to be.
Temperatures will greatly depend on the scenario with highs at
this time trying to rise closer to normal values in the middle 80s
and lows in the 60s.
&&
.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1239 PM CDT TUE AUG 13 2013
Still expect VFR conditions to persist through the forecast as
convection expected to remain west and south of the terminals
through the period. Could see possible fog tonight...but fcst for
high clouds in the area makes confidence in fog potential low...so
will therefore not introduce into at this time. east to northeast
winds will persist generally under 10 kts...but should slowly veer
beyond 12z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...Barjenbruch
LONG TERM...Bowen
AVIATION...63
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1217 PM CDT Tue Aug 13 2013
...Updated for Aviation...
.SYNOPSIS...
ISSUED AT 332 AM CDT TUE AUG 13 2013
During the overnight hours, the heavy rain threat shifted into
central and south-central Kansas while much of southwest Kansas was
beginning to dry out. The longwave trough continued across eastern
Canada into the Great Lakes region...with a reinforcing shortwave
trough digging down into the Great Lakes. This shortwave disturbance
lead to the frontal passage across Kansas on Monday leading to the
evening and late night precipitation event. A mid-upper ridge was
found across the northern Rockies, but it was not very substantial
ridging and and there were even thunderstorm clusters across eastern
Montana within the ridge axis. A 70-80kt 250mb jet also contributed
to the organization of last evening`s precipitation event with the
upper jet extending from near Las Vegas, NV to central Colorado into
eastern Kansas/Nebraska.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 332 AM CDT TUE AUG 13 2013
Main changes in the forecast were lowering the high temperature for
today given the likelihood of cloud cover remaining over much of the
region. NAM12 and RAP models suggest that clouds will certainly hang
in tough for much of the day (especially the RAP model). 700mb
temperatures will be cooler today from +6 to +8C with 850mb temps
+16 to +18C, so with clouds hanging tough and cooler lower
tropospheric temperatures shown by the NAM, RAP, GFS...it is
difficult to see afternoon temperatures getting much above the mid
to upper 70s. Any sunshine in the afternoon, though, will lead to
destabilization and the regeneration of thunderstorms. The strong
upper tropospheric jet will remain across Colorado and southern
Kansas, so the perturbed mid-upper level flow across the central
High Plains will also aid in additional thunderstorm development
late in the day. The most likely location for afternoon thunderstorm
development will be across eastern Colorado and far western
Kansas...farther removed from the influence of last night`s
mesoscale convective system (MCS) and the remnant bubble surface
high left in its wake. Any new thunderstorms this afternoon may
evolve into one or more MCSs, however the best chance at this will
be late in the evening and generally west of a Lakin to Liberal
line.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 420 AM CDT TUE AUG 13 2013
Wednesday:
A 70 kt 250 hPa jet streak will traverse across western Kansas through
the day. At the sfc, an upslope flow regime is expected with weak 850
hPa warm air advection/theta-e advection across far western Kansas.
For spatiotemporal adjustments of precipitation probability percentage
points, have relied heavily on ECMWF output solutions. Wednesday is
shaping up to be another MCS day. Orographic convection is expected
to form across the high plains and then drift southeast across the region
during the late evening and overnight period. The precipitation numerical
values are still in the chance category. The NAM solution is still dry
for the most part - but this model has failed with the MCS events recently,
so I remain dubious of any described solution herein. The tail end of
both WRF cores also support more confidence in the ECMWF solution. Heavy
rain will be possible again as precipitable water values are forecast
around the 75th percentile for a Gaussian distribution. Otherwise, maximums
will be cool because of all the cloud cover and lack of low level downslope
flow. Followed the ECE for guidance, which shows values in the upper
70sF to around 80F. Minimums into Thursday morning will be in the lower
60sF.
Thursday:
Another MCS day is possible Thursday. Upper level flow is more NW during
this period as a result the amplification of 500 hPa ridging across
the spine of the Rockies. This flow may advect any MCS activity farther
east than compared to the previous day. Heavy rain could be a possibility
again, as pwats continue on the higher end of the distribution spectrum.
Maximum surface temperatures could be a few degrees (F) warmer, particularly
across the western zones, as the 850 hPa warm plume advects slightly
farther east. A gradient of upper 80sF to around 80F is expected from
the west to the east with lows in the 60sF.
Friday and beyond:
Stuck with the weighted model solution (allblend) for the rest of the
forecast period as uncertainty continues to increase. There could be
some late afternoon and evening convection across the eastern zones
in association with an enhanced region of 850 hPa frontogenesis that
the ECMWF solutions shows on Friday. A drier forecast is possible next
weekend as the aforementioned 500 hPa ridge amplifies and expands farther
east across the region with a net result of drier northerly flow aloft
and higher mid level geopotential heights. Temperatures will moderate
to near normal during this drier period. Another period of convection
is possible in about a week from now as a trof moves across the northern
prairies. Will continue to tread lightly.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1205 PM CDT TUE AUG 13 2013
As a shortwave trough moves southeastward across south central
Kansas this afternoon, areas of showers and thunderstorms in the
Hays vicinity will move toward KGCK and KDDC by 22z. By 00z expect
the thunderstorm activity to decrease as the shortwave trough moves
east and south.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 78 59 80 61 / 40 40 30 40
GCK 77 60 78 62 / 30 30 30 40
EHA 83 60 81 62 / 30 40 40 40
LBL 82 61 80 63 / 30 30 30 40
HYS 76 60 78 60 / 60 30 30 40
P28 78 62 81 64 / 50 60 10 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...Sugden
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS JACKSON KY
124 PM EDT TUE AUG 13 2013
.UPDATE...
ISSUED AT 124 PM EDT TUE AUG 13 2013
INGESTED THE LATEST OBS DATA TO ESTABLISH NEW TRENDS IN THE HOURLY
FORECAST ELEMENTS. ASIDE FROM THAT THE FORECAST WAS ON TRACK WITH NO
MAJOR CHANGES REQUIRED.
UPDATE ISSUED AT 1127 AM EDT TUE AUG 13 2013
UPDATED THE TODAY PERIOD OF THE FORECAST AND THE HAZARDOUS WEATHER
OUTLOOK. UPDATED THE PRECIPITATION PROBABILITIES FOR THE REST OF
TODAY TO REFLECT THE LATEST TRENDS IN RADAR IMAGERY AND MOS GUIDANCE.
REMOVED MORNING AND AFTERNOON WORDING FROM THE ZONE TEXT PRODUCT AND
DECREASED PRECIPITATION CHANCES FOR THE REST OF THE DAY TO THE 30 TO
50 PERCENT CHANCE RANGE. ISOLATED TO SCATTERED SHOWERS AND STORMS ARE
EXPECTED TO MOVE ACROSS THE AREA TODAY AS A COLD FRONT MAKES ITS WAY
EAST. THIS ACTIVITY...AFTERNOON RAMPING UP A BIT LATE THIS
MORNING...IS EXPECTED TO GRADUALLY TAPER OFF DURING THE AFTERNOON AND
EARLY EVENING HOURS. ALSO REMOVED MENTION OF FLOODING AND HEAVY RAIN
FROM THE HAZARDOUS WEATHER OUTLOOK. IT APPEARS THAT THE THREAT FOR
HEAVY RAIN IS FINALLY OVER FOR EASTERN KENTUCKY.
UPDATE ISSUED AT 725 AM EDT TUE AUG 13 2013
UPDATED THE NEAR TERM GRIDS TO REFLECT THE BANDED SHOWERS CROSSING
THE SOUTHEAST PARTS OF THE CWA. ALSO ADJUSTED THE T/TD GRIDS THROUGH
THE NEXT SEVERAL HOURS TO REFLECT THE LATEST OBS AND TRENDS. THE REST
OF THE FORECAST REMAINS ON TRACK. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 450 AM EDT TUE AUG 13 2013
08Z SFC ANALYSIS SHOWS A COLD FRONT FINALLY STARTING TO PRESS SOUTH
TOWARD THE OHIO RIVER WITH A DRIER AIR MASS BEHIND IT. AHEAD OF
THIS...THOUGH...PLENTY OF SHOWERS AND ISOLATED THUNDERSTORMS ARE
BRINGING ADDITION BOUTS OF HEAVY RAINS TO EAST KENTUCKY THIS MORNING.
EXPECT THE RAINS...AND OCCASIONAL THUNDER...TO CONTINUE INTO THE
MORNING HOURS AS THE FRONT GETS CLOSER AND STARTS SHUNTING THE DEEPER
MOISTURE...THAT HAS BEEN OVER US FOR MORE THAN A WEEK...SOUTH. PATCHY
FOG IS ALSO FOUND OUT THERE WITH DEWPOINTS AND TEMPS NEARLY THE SAME
AT EACH OBS SITE...IN THE UPPER 60S AND LOWER 70S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THE
DEEP TROUGH PIVOTS SOUTH FROM CANADA INTO THE GREAT LAKES TODAY. A
TROUGH AXIS FROM THIS WILL SWEEP THROUGH THE OHIO VALLEY ON
WEDNESDAY...BUT BY THEN THE LOWER LEVELS WOULD HAVE CLEARED OUT THE
DEEPER MOISTURE THROUGHOUT THE AREA. BEFORE THIS HAPPENS...DEEP LAYER
SOUTHWEST FLOW LEVELS WILL CONTINUE TO SUPPLY EAST KENTUCKY WITH
PLENTY OF MOISTURE THROUGH THE FIRST PART OF THE DAY. GIVEN THE MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM FOR THIS FORECAST
WITH A BLEND TOWARD THE HRRR AND RADAR TRENDS IN THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE ANOTHER 12 HOURS OR SO OF SHOWERS AND
THUNDERSTORMS AND ISOLATED HEAVY RAIN BEFORE THE DRIER AND COOLER AIR
MOVES INTO EAST KENTUCKY. HAVE CONTINUED TO HIT THIS HARD IN THE
HWO...ZONES AND GRIDS. A MUCH MORE COMFORTABLE EVENING CAN BE
EXPECTED THROUGH THE AREA...BUT ESPECIALLY NORTHERN PARTS...AS THE
LOWER DEWPOINT AIR FILTERS DOWN OUR WAY. AM CONCERNED THAT THE
DEEPER VALLEYS TONIGHT MAY NOT MIX DOWN THAT DRY AIR AS EFFECTIVELY
AS THE REST OF OUR GEOGRAPHY SETTING THE STAGE FOR FOG...LOCALLY
DENSE. ANY FOG WILL QUICKLY MIX OUT BY MID MORNING ON WEDNESDAY WITH
A PLEASANT DAY TO FOLLOW. THIS SHOULD ALLOW US ALL TO BREATH SOME
RELIEF...DRY OUT...AND TACKLE OUTDOOR PROJECTS THAT THE RAINS OF THE
PAST WEEK HAVE DELAYED.
AGAIN...USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND
DEWPOINTS THROUGH 24 HOURS...THEN CONSALL THEREAFTER. WITH TEMPS...
FAVORED THE CONSALL FOR MAX AND MIN VALUES ALONG WITH ITS DERIVED
DIURNAL CURVE. DID FINE TUNE THE OVERNIGHT LOWS TONIGHT TO REFLECT A
BIT MORE TROUBLE THE COOLER AND DRIER AIR MAY HAVE FILTERING INTO OUR
GEOGRAPHIC NOOK AND CRANNIES. AS FOR POPS...HAVE ENDED UP CLOSER TO
THE VERY WET MET NUMBERS TODAY AND THEN IN LINE WITH THE DRY GUIDANCE
TONIGHT AND WEDNESDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EDT TUE AUG 13 2013
AN AMPLIFIED 50H PATTERN WITH A RIDGE OVER THE ROCKIES AND A TROF
OVER THE ERN CONUS. AT THE SFC...HIGH PRESSURE OVER THE GREAT LAKES WILL
CONTINUE TO PUSH THE COLD FRONT FURTHER TO THE SOUTH WITH DRIER AIR
INFILTRATING THE COMMONWEALTH. THIS PATTERN WILL LEAD TO A MOSTLY DRY
FCST FOR MUCH OF ERN KY UNTIL THE END OF THE WEEK. BY FRI MORNING AN
INVERTED TROF AT THE SFC WILL ALLOW MOISTURE TO CREEP INTO THE AREA
AND DAY TIME HEATING COULD SPARK A FEW SHOWERS. THE FCST WILL KEEP
THE WEATHER DRY UNTIL LATE FRI EVENING. EVEN AS THIS IS HAPPENING...
AT THE 50H LEVEL A VORT MAX IS DROPPING INTO THE CNTRL PLAINS TO
REINFORCE THE ERN TROF. THIS VORT MAX WILL DEVELOP OVER THE WEEKEND
INTO A CLOSED LOW AS THE SFC HIGH PRESSURE SLIPS TO NEW ENG AND
ALLOWS ADDITIONAL MOISTURE TO INVADE THE REGION WITH A GOOD CHANCE
OF PRECIP. THE CLOSED LOW WILL BECOME CUT OFF FROM THE PREVAILING
WESTERLIES ACROSS THE NRN CONUS BORDER.
WITH THE HIGH PRESSURE FILTERING COOLER AIR INTO THE AREA...EXPECT
HIGH TEMPS IN THE UPPER 70S FOR THU BEFORE THE RETURNING SOUTHERLY
FLOW CAN BOOST HIGHS INTO THE LOWER 80S BY FRI. 80S WILL CONTINUE
INTO SAT BEFORE THE EXPECTED PCPN WILL RESTRICT HIGHS BACK TO AROUND
80 FOR SUN AND MON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 124 PM EDT TUE AUG 13 2013
VARIABLE CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THIS
EVENING. SCATTERED SHOWERS AND STORMS ARE EXPECTED TO MOVE ACROSS
EASTERN KENTUCKY THE REST OF TODAY ALONG A DEPARTING COLD FRONT. CIGS
WILL VARY FROM MVFR TO VFR DEPENDING ON THE PROXIMITY OF SHOWERS AND
STORMS TO THE TAF SITES. JKL IN PARTICULAR WILL BE CHALLENGING DUE TO
ITS RIDGETOP LOCATION. SOME MVFR FOG IS EXPECTED TO FORM ACROSS THE
AREA OVERNIGHT...AS SKIES CLEAR OFF AND WINDS DIE DOWN. MOSTLY CLEAR
TO PARTLY CLOUDY SKIES ARE EXPECTED ON WEDNESDAY AS HIGH PRESSURE
SETTLES OVER THE AREA.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GAYLORD MI
148 PM EDT TUE AUG 13 2013
.SYNOPSIS...
ISSUED AT 324 AM EDT TUE AUG 13 2013
HIGH PRESSURE WORKS ITS WAY DOWN INTO THE GREAT LAKES TODAY AND
CAMPS OUT FOR SEVERAL DAYS. RAINFALL CHANCES WILL BE ALMOST
NIL...WITH A HEALTHY DOSE OF BEAUTIFUL SUMMER WEATHER...THAT WILL
WARM INTO THE MIDDLE AND UPPER 70S FOR THE LATTER HALF OF THE WORK
WEEK AND UPCOMING WEEKEND.
&&
.UPDATE...
ISSUED AT 147 PM EDT TUE AUG 13 2013
EVERYTHING ON TRACK FOR THE MOMENT. EMBEDDED SHORT WAVE TROUGH
SEEN IN WATER VAPOR IMAGERY CENTERED JUST NORTHEAST OF SAULT SAINT
MARIE...ROTATING SOUTHWARD WITH SOME COLDER CLOUD TOPS SHOWING UP
ON ENHANCED IR SATELLITE (INDICATIVE OF SOME SYNOPTIC UPWARD
FORCING). SHORT WAVE TROUGH...ALONG WITH ASSOCIATED BETTER MOISTURE
WILL BE DROPPING THROUGH THE REGION THROUGH THE COURSE OF THE
AFTERNOON. MAY ALREADY BE SEEING THE EFFECTS OF INCREASING FORCING
WITH SPOTTY SHOWERS NOW SHOWING UP OVER PARTS OF NRN LOWER
MICHIGAN. SO...BEST CHANCES FOR SHOWERS WILL BE OVER THE NEXT
SEVERAL HOURS INTO EARLY EVENING...WITH THE COMBINED EFFECTS OF
SYNOPTIC FORCING AND LAKE/LAND HEATING INDUCED INSTABILITY.
UPDATE ISSUED AT 1034 AM EDT TUE AUG 13 2013
COLD ADVECTION STILL UNDERWAY ACROSS THE GREAT LAKES ON SOMEWHAT
GUSTY N/NW WINDS...AHEAD OF HIGH PRESSURE BUILDING INTO THE REGION
FROM SOUTH-CENTRAL CANADA. 12Z APX SOUNDING REVEALING AN 850 MB
TEMP OF +4C...RATHER COLD FOR THIS TIME OF YEAR AND FORECAST TO
BOTTOM OUT AROUND +3C TO +4C THIS AFTERNOON. PLENTY COLD ENOUGH
FOR LAKE CONVECTION...AND SURE ENOUGH...LOTS OF TRUE LAKE BANDS
HAVE DEVELOPED ON THE LAKES...PARTICULARLY ON LAKES MICHIGAN AND
HURON.
WITH HEATING...HYBRID LAKE AND LAND HEATING INDUCED STCU WILL
OVERSPREAD THE CWA AS WE GO THROUGH THE REST OF THE MORNING...A
PROCESS ALREADY UNDERWAY PER SATELLITE TRENDS IN THE LAST HOUR OR
SO. DEEP ENOUGH CONVECTION THAT A FEW SHOWERS APPEAR LIKELY THIS
AFTERNOON PARTICULARLY DOWNWIND OF THE LAKES WITH THE MOISTURE
FEED. IN FACT...APX RADAR ALREADY PICKING UP A FEW RETURNS OFF OF
GRAND TRAVERSE BAY. WILL MAKE SOME COSMETIC TWEAKS TO THE GRIDS
FOR SCATTERED SHOWERS AND HAVE INCREASED CLOUD COVER THROUGH THE
AFTERNOON. OTHERWISE...A DOWNRIGHT COOL DAY AHEAD WITH TEMPS A
SOLID 15 DEGREES BELOW NORMAL.
UPDATE ISSUED AT 657 AM EDT TUE AUG 13 2013
INCREASED WIND GUSTS IN A FEW SPOTS...MAINLY OVER THE GREAT
LAKES...PER LATEST OBS AND INCREASING INSTABILITY. LOW LEVEL
MOISTURE EXPECTED TO DEVELOP INTO A PERIOD OF MOSTLY CLOUDY
SKIES...OF WHICH DID MAKE A CHANGE TO EXTEND THIS CLOUDIEST TIME
PERIOD. OTHERWISE...FORECAST LOOKING GOOD.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 324 AM EDT TUE AUG 13 2013
RATHER ENERGETIC...ALBEIT SOMEWHAT MOISTURE STARVED...PATTERN
ESTABLISHED ACROSS THE GREAT LAKES AT THIS EARLY HOUR. YESTERDAY`S
SHOWER AND THUNDERSTORM PRODUCING WAVE HAS EXITED WELL TO OUR
EAST...WITH ANOTHER WAVE QUICK ON ITS HEELS DIVING SOUTHEAST ACROSS
LAKE SUPERIOR. NOT A WHOLE LOT OF SENSIBLE WEATHER GOING ON WITH
THIS SECONDARY WAVE...WITH ANY APPRECIABLE MOISTURE STRIPPED OUT BY
YESTERDAYS SYSTEM. THAT SAID...THIS WAVE HAS PLENTY OF UNSEASONABLY
COLD AIR ASSOCIATED WITH IT...WITH HIGH RES RAP GUIDANCE SHOWING H8
TEMPERATURES IN THE LOWER SINGLE DIGITS OVER EASTERN LAKE
SUPERIOR...WITH -20C H5 READINGS MOVING SOUTH ACROSS THE BIG LAKE AS
WELL. PLENTY OF COLD ENOUGH AIR TO DRUM UP A LAKE RESPONSE...WITH
WELL EVIDENT STCU STREAMERS DEVELOPING OVER NORTHERN LAKE
MICHIGAN...HURON...AND FAR EASTERN LAKE SUPERIOR. MOISTURE
PROFILES/DEPTH NOT QUITE DEEP ENOUGH TO GENERATE ANY SHOWER ACTIVITY
PER RADAR AND OBSERVATION. SUPPOSE A SPRINKLE MAY BE FALLING OUT OF
THIS CLOUD DECK...JUST TOO LIGHT TO BE PICKED UP OUR RADAR. WHILE
SURFACE CAA NOT QUITE AS IMPRESSIVE AS WHAT IS HAPPENING
OVERHEAD...STILL QUITE CHILLY OUT THERE WITH CURRENT READINGS MAINLY
IN THE UPPER 40S AND 50S. SHORT TERM FORECAST CONCERNS THROUGH
TONIGHT CENTER ON TEMPERATURE/CLOUD TRENDS AS WELL AS SHOWER
POTENTIAL AS UPSTREAM WAVE AND ATTENDANT COLD CORE PUSH THROUGH THE
REGION.
KNOCKING THE EASY PORTION OF THE FORECAST OUT OF THE WAY...
TEMPERATURES TODAY AND TONIGHT WILL RUN SEVERAL DEGREES BELOW
NORMAL. CULPRIT IS AFOREMENTIONED COLD CORE SYSTEM AND INTENSIFYING
LOW LEVEL CAA WITHIN SOMEWHAT GUSTY NORTHWEST SURFACE WINDS. HIGHS
TODAY WILL STRUGGLE THROUGH THE MIDDLE AND UPPER 60S...A GOOD 10
DEGREES OR SO BELOW NORMAL (AT LEAST THE WINDS WON`T MAKE IT FEEL
ANY COLDER...OH...NEVER MIND). AS FOR RAIN POTENTIAL...MAIN WAVE AND
UPWARD QG RESPONSE MOVES THROUGH THIS MORNING...LEAVING OVERHEAD
COLD POOL AND POSSIBLE LAKE CONTRIBUTIONS FOR SHOWER GENERATION. NOT
A FAN OF SEEING MUCH WITH THE LATTER AS WE HEAD THROUGH THE DAY
GIVEN STRONG DIURNAL DISRUPTION AND DRYING LOW LEVELS. LAKES LIKELY
WILL ADD AT LEAST SOME BOUNDARY LAYER MOISTURE...PERHAPS HELPING THE
OVERHEAD COLD POOL KICK OFF A FEW MOSTLY INTERIOR SHOWERS. H5
TEMPERATURES NEAR -20C DEFINITELY SUPPORTS THIS NOTION.
INTERESTINGLY...BOTH NAM-WRF AND GFS BUFFER SOUNDINGS SHOW A
RELATIVE WARN NOSE CENTERED AROUND H7...WITH SURFACE BASED PARCELS
JUST BARELY SCRAPPING BY THIS LEVEL. REALLY LIKE LOOK OF INHERITED
FORECAST FEATURING LOW END SHOWER POTENTIAL...ESPECIALLY ACROSS
CLIMATOLOGICALLY FAVORED ARES OF NORTHEAST LOWER AND PARTS OF EASTERN
UPPER MICHIGAN. WILL MAKE SOME MINOR CHANGES...BUT GIST OF FORECAST
WILL ESSENTIALLY REMAIN UNCHANGED. PLENTY OF DIURNALLY DRIVEN
CU/STCU EXPECTED OTHERWISE...LEADING TO A PARTLY TO MOSTLY CLOUDY
DAY. YUP...GOING TO FEEL A LOT LIKE THE MIDDLE OF SEPTEMBER!
STRONG CANADIAN HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
GREAT LAKES TONIGHT...WITH MID LEVEL COLD POOL AND DEEPEST TROUGHING
PUSHING OFF TO OUR EAST. THIS SHOULD END ANY LINGERING SHOWER THREAT
QUICKLY LATER THIS AFTERNOON...LEADING TO A DRY OVERNIGHT. CLOUD AND
TEMPERATURE TRENDS MUCH MORE FORMIDABLE CHALLENGES. GUIDANCE BACKING
AWAY FROM ROTATING EASTERN LAKES CLOUD DECK BACK WEST INTO OUR
AREA...AND FEEL THE NAM IS MUCH TOO AGGRESSIVE KICKING OFF STRATUS
ACROSS THE HIGHLANDS GIVING FLOW PATTERN AND GIVING JUST OFF THE
DECK VERY DRY AIR. WILL HEDGE OPTIMISTICALLY (YUP...I SAID IT) AND
GO MAINLY CLEAR THROUGH MUCH OF THE OVERNIGHT. UNSEASONABLY COLD
AIRMASS ARGUES FOR SOME VERY CHILLY READINGS...ESPECIALLY IF CLEAR
SKIES COME TO FRUITION. HOWEVER...NOT ENTIRELY SOLD ON JUST HOW COLD
READINGS BECOME TONIGHT...WITH CENTER OF HIGH PRESSURE REMAINING
JUST UPSTREAM. WILL NUDGE INHERITED LOWS DOWN A TOUCH...INTRODUCING
NEAR 40 DEGREE READINGS IN THE TRADITIONAL ICE BOX LOCATIONS
(GRAYLING...ATLANTA...AND SUCH). IF FULL DECOUPLING IS
REALIZED...THESE READINGS WILL LIKELY BE A TOUCH TO "WARM"...WITH
SOME MID AND UPPER 30S DEFINITELY PLAUSIBLE. EITHER WAY...ANOTHER
CHILLY MID AUGUST NIGHT FOR THE NORTH WOODS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 324 AM EDT TUE AUG 13 2013
A MOISTURE-STARVED NORTHWEST FLOW ALOFT WILL GRADUALLY BECOME MORE
ZONAL LATER THIS WEEK AND INTO THE UPCOMING WEEKEND...WITH COOLISH
TEMPERATURES WARMING OVER THIS TIME. THERE IS ALMOST NO CHANCE FOR
RAINFALL FOR THE NEXT SEVERAL DAYS...AT LEAST ANY CHANCE THAT
WOULD BE WORTHY OF BEING INTRODUCED INTO THE FORECAST RIGHT NOW.
WEDNESDAY THROUGH FRIDAY...A STOUT NW FLOW ALOFT WILL LOOSEN UP
OVER THIS TIME...WITH SLOWLY RISING HEIGHTS...AS RIDGING FROM THE
ROCKIES JUST SLOWLY BLEEDS INTO THE HEART OF THE COUNTRY. THERE IS
A SERIOUS LACK OF MOISTURE OVER THIS TIME...WITH NO CHANCES FOR
RAIN CURRENTLY IN THE FORECAST...OR EVEN CONSIDERED INTO THE
FORECAST. THAT SAID...THERE IS A DECENT SHORTWAVE DROPPING IN
ACROSS EASTERN ONTARIO/QUEBEC ON THURSDAY...THAT WILL TRY AND LAY
OUT A STRIP OF "DEEPER" MOISTURE ALONG SFC TROUGH/COLD FRONT IN
EASTERN UPPER. SOMETHING TO KEEP AN EYE ON. TEMPERATURES IN THE
MIDDLE AND UPPER 60S WEDNESDAY WILL WARM INTO THE 70S FOR THURSDAY
AND FRIDAY. THE MAIN WEATHER STORY MAY BE THE DRYNESS OF THE BL
OVER THIS TIME...WITH MODELS MORE THAN LIKELY UNDER-FORECASTING THE
MIXING THAT WILL TAKE PLACE. FCST SOUNDINGS SUGGEST +10F DECREASES
IN SFC TDS FROM THE MOS NUMBERS. IT`LL BE A DRY LOW LEVEL AIR
MASS...BUT WITH WINDS GENERALLY 10KTS OR LESS...FIRE WEATHER
CONCERNS ARE MINIMAL.
SATURDAY THROUGH MONDAY...SFC HIGH PRESSURE WILL BE OVER THE EAST
COAST...BUT TRAILING BACK WESTWARD AND INTO THE GREAT LAKES. THE
PATTERN IS VERY SLOW TO MORPH INTO A WEAK ZONAL FLOW. TEMPERATURES
WILL CREEP UP INTO THE UPPER 70S AND LOWER 80S OVER THIS
TIME...AND AGAIN...WITH VERY MINIMAL CHANCES FOR PRECIPITATION.
THERE IS A SUGGESTION THAT A PIECE OF SHORTWAVE ENERGY GETS CUT OFF
TO OUR SW...WHICH COULD TECHNICALLY ROAM UP OUR WAY...BUT THE
BETTER CHANCE FOR RAIN MAY EVENTUALLY BE WITH A SHORTWAVE AND SFC
TROUGH/THETA-E BUMP MORE TOWARD TUESDAY. MAY EVEN STILL BE LOOKING
AT CONTINUED LOW AFTERNOON DEW POINTS...MUCH LOWER THAN MODEL
NUMBERS.
VERY BEAUTIFUL WEATHER IN STORE FOR US.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 147 PM EDT TUE AUG 13 2013
LOTS OF CLOUD COVER DRAPED ACROSS NRN LOWER MICHIGAN THIS
AFTERNOON THANKS TO DAYTIME HEATING AND COLD POOL ALOFT DROPPING
DOWN THROUGH THE REGION. SPOTTY SHOWERS SHOWING UP ACROSS THE TIP
OF THE MITT NEAR KPLN AND ADDITIONAL SHOWER DEVELOPMENT IS
ANTICIPATED THIS AFTERNOON AS SHORT WAVE DROPS DOWN THROUGH THE
REGION. CIGS WILL REMAIN LARGELY VFR...ALTHOUGH BRIEF BOUTS OF
MVFR CIGS ARE POSSIBLE INTO THE EARLY EVENING. GUSTY NORTH WINDS
WILL PERSIST WITH HIGHEST GUSTS REACHING THE LOW 20 KNOT RANGE.
TONIGHT...WILL THIN OUT QUITE A BIT OF THE CLOUD COVER WITH LOSS
OF HEATING...ALTHOUGH TVC/APN MAY RETAIN SCT-BKN CONDITIONS WITH
FLOW OFF THE LAKES. GUSTINESS SUBSIDES BUT WE WILL MAINTAIN A
SUSTAINED 5 TO 10 KNOT NORTH-NORTHWEST WIND THROUGH THE NIGHT.
WINDS TURN MORE NORTHWESTWARD ON WEDNESDAY BUT WITH A BIT LESS
GUSTINESS. SCT-BKN VFR CIGS AGAIN ON WEDNESDAY PARTICULARLY AT
APN.
&&
.MARINE...
ISSUED AT 324 AM EDT TUE AUG 13 2013
MARINE...CONDITIONS MUCH MORE REMINISCENT OF EARLY FALL THAN
AUGUST...WITH CANADIAN HIGH PRESSURE BRINGING A BLAST OF
UNSEASONABLY CHILLY AIR TO THE BIG WATERS. RATHER TIGHT PRESSURE
GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL EASILY ALLOW
GOOD DEEP LAYER MIXING OVER THE WATERS...PRODUCING GUSTY NORTHWEST
WINDS. LOOKS LIKE TWO CORRIDORS OF STRONGER WIND GUSTS...ONE THROUGH
EARLY THIS MORNING...WITH ANOTHER AS WE HEAD THROUGH THIS AFTERNOON
AND EARLY EVENING. PLETHORA OF SCA CONDITIONS EXPECTED...A
COMBINATION OF GUSTY WINDS AND INCREASINGLY CHOPPY CONDITIONS. WINDS
BEGIN TO DIE OFF SOME HEADING INTO LATER TONIGHT AND WEDNESDAY AS
THEY SLOWLY BACK MORE WESTERLY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LSZ321.
&&
$$
UPDATE...BA
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...BA
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 PM EDT TUE AUG 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT TUE AUG 13 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
QUEBEC INTO NRN ONTARIO RESULTING IN CYCLONIC WNW FLOW THROUGH THE
NRN GREAT LAKES. LITTLE MORE THAN PATCHY MID CLOUDS WERE ASSOCIATED
WITH A SHORTWAVE TROUGH MOVING THROUGH WRN LAKE SUPERIOR WHILE MORE
EXTENSIVE CLOUDS AND A FEW SPRINKLES WERE OBSERVED WITH ANOTHER
SHRTWV JUST UPSTREAM...TO THE N OF LAKE SUPERIOR. AT THE SFC...HIGH
PRES OVER MANITOBA INTO NW MN WAS BUILDING INTO THE WRN LAKES WITH
NRLY FLOW PREVAILING ACROSS LAKE SUPERIOR INTO UPPER MICHIGAN.
TODAY...AS THE SHRTWV FROM N OF THE LAKE AND A POCKET OF LOWER 700 MB
TEMPS AROUND -6C...DROPS THROUGH THE CWA...MODELS SUGGEST THAT SOME
ISOLD SHOWERS WILL BE POSSIBLE FROM LATE THIS MORNING INTO THE EARLY
AFTERNOON...MAINLY THROUGH W CNTRL UPPER MI. IN ITS WAKE...SUBSIDENCE
AND DRYING WILL BUILD QUICKLY INTO THE AREA...ENDING ANY PCPN BY MID
TO LATE AFTERNOON.
TONIGHT...WITH CLEARING SKIES AND LIGHT WINDS AS THE HIGH BUILD INTO
THE REGION...FAVORABLE RADIATIONAL COOLING CONDITIONS IN THE DRY
AIRMASS(PWAT TO AROUND 0.50 INCH OR 50 PCT OR NORMAL) WILL ALLOW
TEMPERATURES TO DROP TOWARD THE LOWER END OF GUIDANCE....INTO THE
MID TO UPPER 30S INLAND WEST. THE TYPICAL COLDER LOCATIONS FROM
CHAMPION AND AMASA TO WATERSMEET...KENTON AND WATERSMEET COULD SEE
SOME PATCHY FROST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 432 AM EDT TUE AUG 13 2013
THE VERY COOL MORNING TEMPS WILL QUICKLY RISE INTO THE UPPER 60S TO
MID 70S WEDNESDAY AS THE SFC HIGH OVERHEAD CONTINUES TO SLOWLY SINK
TO OUR SSE. A SLOW WARMING TREND WILL BEGIN WEDNESDAY NIGHT...WITH
THE SFC HIGH LINGERING ACROSS THE OHIO VALLEY AND NEW ENGLAND STATES
THROUGH AT LEAST THE START OF THE NEXT WORK WEEK.
THURSDAY WILL SEE A RETURN OF NEAR NORMAL HIGH TEMPS...IN THE
70S...AS 850MB TEMPS FINALLY RISE INTO THE DOUBLE DIGITS AND...STAY
THERE FOR THE REMAINDER OF THE FCST PERIOD.
THERE WILL BE ONLY FEW SYSTEMS OF NOTE OVER THE WEEK...WITH NW FLOW
ALOFT REMAINING IN PLACE THROUGH THE END OF THE WORK WEEK. THE MAIN
500MB LOW WILL BE SPINNING AROUND AND NEAR QUEBEC THROUGH THURSDAY
BEFORE EJECTING NE IN THE MAIN FLOW AROUND THE STRONGER POLAR LOW. A
SERIES OF SHORTWAVES WILL ATTEMPT TO ROUND THE HIGH AMPLITUDE RIDGE
OVER MUCH OF THE WESTERN STATES EARLY TO MID WEEK...
SEEING A SFC LOW TRACKING FROM S ALBERT AND SASKATCHEWAN ON FRIDAY
TO S CENTRAL CANADA OVER THE WEEKEND. THE 12/12Z ECMWF IS MUCH
QUICKER TO PUSH THE SFC LOW ACROSS HUDSON BAY OVER THE WEEKEND.
THERE ARE SIGNIFICANT ENOUGH TIMING DIFFERENCES BETWEEN THE
AVAILABLE GUIDANCE TO KEEP ONLY LIGHT CHANCE POPS IN THE FCST AS
WARM BUT MAINLY DRY AIR PUSHES IN ON SW WINDS AT THE SFC SATURDAY
THROUGH THE END OF THIS FCST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 127 PM EDT TUE AUG 13 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT ALL TAF
SITES...EXCEPT REALLY EARLY THIS AFTERNOON AT SAW. INSTABILITY SC
WITH A DISTURBANCE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT TUE AUG 13 2013
NRLY WINDS OF 15 TO 20 KNOTS OVER THE ERN PORTIONF OF LAKE SUPERIOR
WILL DIMINISH TONIGHT AS HIGH PRES BUILDS INTO THE REGION. AS THE
HIGH SINKS TO THE SOUTH WED INTO WED NIGHT WRLY WINDS OF 15 TO 20
KNOTS ARE ALSO EXPECTED OVER CNTRL AND ERN LAKE SUPERIOR.
OTHERWISE...WINDS AOB 15 KNOTS WILL PREVAIL INTO SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GLASGOW MT
336 PM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
WARM AND HUMID CONDITIONS HAVE CONTRIBUTED TO ISOLATED THUNDERSTORMS
WITH HEAVY RAIN TODAY. ONE EXAMPLE WAS 2.8" IN SOUTHWEST DANIELS
COUNTY.
SHOWERS PRESENTLY MOVING SE INTO ROOSEVELT COUNTY BUT ATMOSPHERE IS
UNSTABLE TO THE SOUTH WITH CAPE ABOUT 1000 J/KG AND DEWPOINTS IN THE
UPPER 50S TO LOW 60S. CERTAINLY RIPE CONDITIONS FOR HEAVY RAIN. RUC
AND HRRR CONTINUE TO SHOW THIS INTO THE EVENING HOURS MAINLY IN THE
EASTERN ZONES. THREAT SHOULD END THEREAFTER.
ON WEDNESDAY...DIURNAL HEATING WILL SPARK SHOWERS AND THUNDERSTORMS
AGAIN AS UPPER LEVELS REMAIN UNSETTLED WITH LOW LEVEL WARMTH AND
HUMIDITY. NOT CONFIDENT ENOUGH TO PIN-POINT WHERE HEAVY RAINS WILL
OCCUR AND DIDN/T FEEL COMFORTABLE TO BROADBRUSH THIS. SMALL HAIL AND
GUSTY WINDS ARE ALSO POSSIBLE BUT AGAIN DID NOT WANT TO
BROADBRUSH...AND IT/S ALREADY MENTIONED IN THE HWO.
BY THURSDAY...THE UPPER RIDGE BUILDS IN AND SUPPRESSES CONVECTION.
WITH MORE SUNSHINE...TEMPERATURES WILL BE WARMER. AIRMASS WILL BE
MORE HUMID OVER THE EASTERN ZONES BUT ANY THUNDERSTORM DEVELOPMENT
WILL BE OVER THE DAKOTAS. TFJ
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
A GOOD CHUNK OF THE PREVIOUS FORECAST STILL STANDS... BUT A COUPLE
PLACES NEEDED TWEAKING. FIRST... OVERNIGHT LOWS POST FRIDAY RIDGE
NEEDED TO BE DRUG DOWN AS THEY WARMED FAR TOO FAST FOR SOUTHWEST
FOLLOWED BY ZONAL FLOW ALOFT THROUGH EARLY NEXT WEEK. ALSO...
ACTED TO STRIP OUT ZERO POPS FOR THE SAME TIME PERIOD AS
VARIABILITY BEGINS TO CREEP INTO THE FORECAST POST SUNDAY AMONG
OPERATIONAL EC VERSUS ITS ENSEMBLE MEMBERS... WHILE NO REAL
ANALOGS FROM THE PAST 60 DAYS ARE YET AVAILABLE FOR THESE PERIODS.
GAH
PREVIOUS LONG TERM DISCUSSION...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. MVFR POSSIBLE WITH EVENING THUNDER OR
OVERNIGHT FOG.
THUNDER: SCATTERED SHOWERS AND THUNDERSTORMS ARE IN SWING THIS
AFTERNOON NEAR THE KOLF... KSDY... AND KGDV TERMINALS AND MAY
CONTINUE THROUGH THE EARLY EVENING. AMENDMENTS MAY BE NEEDED. AS
USUAL... BRIEF VISIBILITY OBSCURATION AND SUDDEN GUSTY WINDS ARE
POSSIBLE NEAR ANY THUNDERSTORM.
FOG: WHILE CHANCES ARE NOT HIGH ENOUGH TO DIRECTLY INCLUDE IN THE
TAFS... A SMALL CHANCE FOR FOG DOES EXIST AT KOLF OR KSDY TONIGHT.
FOG IS MOST POSSIBLE NEAR THE EXCESS OF MOISTURE FROM SHOWERS
EARLIER IN THE EVENING. BEST WINDOW FOR FOG WOULD BE BETWEEN 08Z
AS WINDS DROPS OFF THROUGH 13Z RIGHT AFTER SUN UP.
AREA WINDS: WINDS WILL BE OUT OF THE SOUTH AND EAST AROUND 10 KTS
SUSTAINED... GUSTING UP TO 15 KTS DURING THE AFTERNOON.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
229 PM MDT TUE AUG 13 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
WARM AND HUMID CONDITIONS HAVE CONTRIBUTED TO ISOLATED THUNDERSTORMS
WITH HEAVY RAIN TODAY. ONE EXAMPLE WAS 2.8" IN SOUTHWEST DANIELS
COUNTY.
SHOWERS PRESENTLY MOVING SE INTO ROOSEVELT COUNTY BUT ATMOSPHERE IS
UNSTABLE TO THE SOUTH WITH CAPE ABOUT 1000 J/KG AND DEWPOINTS IN THE
UPPER 50S TO LOW 60S. CERTAINLY RIPE CONDITIONS FOR HEAVY RAIN. RUC
AND HRRR CONTINUE TO SHOW THIS INTO THE EVENING HOURS MAINLY IN THE
EASTERN ZONES. THREAT SHOULD END THEREAFTER.
ON WEDNESDAY...DIURNAL HEATING WILL SPARK SHOWERS AND THUNDERSTORMS
AGAIN AS UPPER LEVELS REMAIN UNSETTLED WITH LOW LEVEL WARMTH AND
HUMIDITY. NOT CONFIDENT ENOUGH TO PIN-POINT WHERE HEAVY RAINS WILL
OCCUR AND DIDN/T FEEL COMFORTABLE TO BROADBRUSH THIS. SMALL HAIL AND
GUSTY WINDS ARE ALSO POSSIBLE BUT AGAIN DID NOT WANT TO
BROADBRUSH...AND IT/S ALREADY MENTIONED IN THE HWO.
BY THURSDAY...THE UPPER RIDGE BUILDS IN AND SUPPRESSES CONVECTION.
WITH MORE SUNSHINE...TEMPERATURES WILL BE WARMER. AIRMASS WILL BE
MORE HUMID OVER THE EASTERN ZONES BUT ANY THUNDERSTORM DEVELOPMENT
WILL BE OVER THE DAKOTAS. TFJ
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
A GOOD CHUNK OF THE PREVIOUS FORECAST STILL STANDS... BUT A COUPLE
PLACES NEEDED TWEAKING. FIRST... OVERNIGHT LOWS POST FRIDAY RIDGE
NEEDED TO BE DRUG DOWN AS THEY WARMED FAR TOO FAST FOR SOUTHWEST
FOLLOWED BY ZONAL FLOW ALOFT THROUGH EARLY NEXT WEEK. ALSO...
ACTED TO STRIP OUT ZERO POPS FOR THE SAME TIME PERIOD AS
VARIABILITY BEGINS TO CREEP INTO THE FORECAST POST SUNDAY AMOUNG
OPERATIONAL EC VERSUS ITS ENSEMBLE MEMBERS... WHILE NO REAL
ANALOGS FROM THE PAST 60 DAYS ARE YET AVAILABLE FOR THESE PERIODS.
GAH
PREVIOUS LONG TERM DISCUSSION...
THE LONG TERM FORECAST PERIOD BEGINS WITH A STRONG UPPER LEVEL
RIDGE IN PLACE WITH ITS AXIS DIRECTLY THROUGH NORTHEAST MONTANA.
EXCELLENT MODEL AGREEMENT IN KEEPING THE ENTIRE CWA CONSEQUENTLY
DRY. THIS WILL ALLOW THE HOTTEST TEMPERATURES OF THE SUMMER SEASON
TO FINALLY ARRIVE...TOPPING OUT IN THE LOW TO MID 90S...ALTHOUGH
SOME NUMERICAL GUIDANCE SUGGESTS THAT EVEN THIS MAY BE TOO
CONSERVATIVE FOR FRIDAY AND SATURDAY HIGH TEMPERATURES. FOR NOW
FELT IT WAS BEST TO SHOW A GRADUAL INCREASE UNTIL MORE MODEL
CONSENSUS IS EVIDENT.
WITH A COOL FRONT SET TO MOVE THROUGH THE AREA ON SATURDAY
NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE ON THE HEELS
OF SOME MUCH AWAITED NORTHWESTERLY SURFACE WINDS UNDER
SOUTHWESTERLY FLOW ALOFT COURTESY OF THE UPPER LEVEL TROUGH OVER
THE PACIFIC NORTHWEST COASTAL AREA. THIS UNSETTLED PERIOD SHOULD
REMAIN OVER THE REGION WHILE A SHORT WAVE TROUGH PUSHES THROUGH
THE AREA THROUGH MONDAY MORNING...WITH THE BEST CHANCES FOR PRECIP
FOCUSED FROM SATURDAY NIGHT THROUGH SUNDAY MORNING.
MONDAY AND BEYOND...STRONG SUMMER RIDGING FROM THE SOUTHWEST MOVES
IN AGAIN TO CUT OFF THE PRECIPITATION WITH TEMPERATURES WARMING
BACK UP INTO THE 90S.
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. MVFR POSSIBLE WITH THUNDER OR HAZE.
THUNDER: THE EDGE OF A RIDGE WILL PROVIDE ENOUGH LIFT FOR SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP NEAR THE KOLF... KSDY... AND KGDV
TERMINALS THIS AFTERNOON... HOWEVER CHANCES ARE NOT HIGH ENOUGH TO
PLACE DIRECTLY IN THE TAFS. THEREFORE WILL GO WITH CB/S UNTIL KICK
OFF TIME AROUND 18 TO 21Z AND AMEND AS NEEDED. AS USUAL... BRIEF
VISIBILITY OBSCURATION AND SUDDEN GUSTY WINDS ARE POSSIBLE NEAR
ANY THUNDERSTORM.
HAZE: HAZE FROM FIRES TO THE WEST HAS REDUCED VISIBILITY TO WELL
LESS THAN 20 MILES AT TIMES AND ACCORDING TO PREVIOUS OBSERVATIONS
ON RARE OCCASIONS CAN REACH THE MVFR OBSCURATION OF 5 MILES.
HOWEVER... THIS IS FAR TOO RARE TO PLACE IN THE TAFS DIRECTLY.
WILL AMEND IF BECOMES NECESSARY.
AREA WINDS: WINDS WILL BE OUT OF THE SOUTH AND EAST AROUND 10 KTS
SUSTAINED... GUSTING UP TO 15 KTS DURING THE AFTERNOON.
GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
520 PM CDT TUE AUG 13 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
WE HAD A MESOSCALE CONVECTIVE VORTEX (MCV) TRACK ACROSS OUR FORECAST
AREA THIS MORNING INTO THE EARLY AFTERNOON HOURS. THIS BROUGHT
WIDESPREAD RAINFALL TO OUR FORECAST AREA AND HAS WORKED OVER THE
ATMOSPHERE ENOUGH THAT ADDITIONAL PRECIPITATION THIS EVENING INTO
TONIGHT IS UNLIKELY. THE CONVECTION THAT TRACKED THROUGH OUR AREA
HAS NOW PASSED SOUTH INTO CENTRAL KANSAS AND NEW STORMS HAVE ALSO
FORMED TO OUR WEST OVER THE HIGH PLAINS OF WESTERN NEBRASKA.
THE WESTERN NEBRASKA THUNDERSTORMS HAVE FORMED ALONG THE LEADING
EDGE OF THE NEXT SHORTWAVE THAT IS TRACKING SOUTHEAST FROM EASTERN
WYOMING/SOUTHWEST SOUTH DAKOTA INTO WESTERN NEBRASKA. DEEP MOISTURE
CONVERGENCE AND AFTERNOON DESTABILIZATION IS ALSO MAXIMIZED ACROSS
WESTERN NEBRASKA INTO THE BLACK HILLS AND THIS IS WHERE ADDITIONAL
THUNDERSTORMS ARE EXPECTED TO FORM THIS EVENING. THIS IS A WEAKLY
SHEARED ENVIRONMENT AND STORM PROPAGATION WILL GENERALLY BE A SLOW
DRIFT TO THE SOUTH...WHICH SHOULD KEEP THE WESTERN STORMS JUST TO
THE WEST OF OUR FORECAST AREA TONIGHT. THERE IS AN OUTSIDE CHANCE OF
OUR WESTERN ZONES SEEING A PREDAWN SHOWER/THUNDERSTORM SHOULD THE
BLACK HILLS CONVECTION MAKE IT THIS FAR SOUTHEAST. HOWEVER...MOST
FORECAST MODEL DATA KEEPS ALL CONVECTION WEST OF OUR FORECAST AREA
TONIGHT AND THUS WE WILL KEEP ALL ZONES DRY TONIGHT...WHILE KEEPING
AN EYE ON THE WEST FOR THE POSSIBILITY OF NEEDING TO THROW SOME POPS
IN THE FORECAST DEPENDING ON FUTURE RADAR TRENDS.
THERE IS SOME POTENTIAL OF FOG TONIGHT GIVEN THE RECENT WIDESPREAD
RAINFALL. HOWEVER...FORECAST MODELS ARE MIXED ON FOG POTENTIAL WITH
THE HRRR MORE FAVORABLE FOR FOG WHILE THE SREF WOULD NOT GIVE US ANY
FOG. ULTIMATELY FOG WILL LARGELY HINGE ON CLOUD COVER AND SUBSEQUENT
COOLING. HAVE LEFT FOG OUT OF THE FORECAST FOR NOW...BUT SHOULD WE
CLEAR OUT AND REMAIN CLEAR THROUGH MOST OF THE NIGHT...THEN COOLING
MIGHT BE ADEQUATE FOR SOME AREAS OF FOG EARLY WEDNESDAY MORNING.
WEDNESDAY...A SHORT WAVE TROUGH WILL TRACK SOUTHEAST ACROSS WESTERN
NEBRASKA. INSTABILITY AND DEEP LAYER SHEAR WILL BE FAIRLY WEAK TO
MODEST AT BEST AND THUS AM NOT EXPECTING SEVERE WEATHER...BUT CAN
NOT RULE OUT A COUPLE OF STRONG THUNDERSTORMS IN ASSOCIATION WITH
PEAK AFTERNOON HEATING. THE BEST CHANCE OF THUNDERSTORMS WILL BE
ACROSS OUR WESTERN ZONES AND TO THE WEST OF OUR FORECAST AREA IN
ASSOCIATION WITH THE APPROACHING SHORTWAVE. TEMPERATURES WILL REMAIN
COOL FOR AUGUST DUE TO A CONTINUATION OF THE COOL AIRMASS
OVERHEAD...CLOUDS...AND POSSIBLE PRECIPITATION. HIGHS WILL GENERALLY
BE IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
THE MAIN HIGHLIGHTS OF THIS 6-DAY PERIOD ARE A CONTINUATION OF
CHALLENGING SHOWER/THUNDERSTORM CHANCES IN THE WED NIGHT THROUGH
FRIDAY TIME FRAME WHICH MIGHT EVEN FEATURE A STRONG-SEVERE STORM
THREAT CENTERED ON THURSDAY...FOLLOWED BY WHAT APPEARS TO BE A
PREDOMINANTLY DRY WEEKEND...AND THEN A RETURN TO VERY UNCERTAIN
RAIN CHANCES IN THE SUNDAY NIGHT-TUESDAY TIME FRAME AS THE PATTERN
CHANGES A BIT. ITS BEEN A TOUGH GO OF IT LATELY TRYING TO
DETERMINE HOW HARD TO HIT...OR BACK OFF...POPS EVEN IN THE FIRST
24 HOURS...SO THESE UNCERTAINTIES CONTINUE TO BE MAGNIFIED EVEN IN
THE DAY 2-3 TIME FRAME. OF HIGHER CONFIDENCE IS THAT A FAIRLY
REMARKABLE RUN OF SUB-90 DEGREE TEMPS WILL CONTINUE...WITH THE
MAJORITY OF THE CWA FORECAST TO TOP OUT IN THE LOW-MID 80S DURING
THIS TIME FRAME...WITH KS ZONES AS USUAL MOST FAVORED TO REACH
UPPER 80S ON A FEW DAYS. AS FOR LOW TEMPS...EVERY NIGHT IS
EXPECTED TO BE FAIRLY SIMILAR AND RATHER UNIFORM ACROSS THE
CWA...EITHER IN THE LOW OR MID 60S.
STARTING OFF WEDNESDAY EVENING/NIGHT...GAVE A BEST-STAB AT TWO
6-HOUR POP BLOCKS HEAVILY BASED ON MET/MAV GUIDANCE BLEND...WITH
THE EVENING PERIOD FEATURING 20S-40S...AND THE LATE NIGHT PERIOD
RANGING FROM ONLY 20S FAR WEST TO 50S IN EASTERN-MOST NEB ZONES.
IN OTHER WORDS...THERE IS A DECENT CHANCE THAT PARTS OF THE CWA
WILL SEE RAIN...BUT CONFIDENCE IN TIMING/PLACEMENT PRECLUDES
LIKELY POPS ANYWHERE YET. ON THE LARGE-SCALE ALOFT...LEGITIMATE
NORTHWEST-FLOW IS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN A
RIDGE AXIS EXTENDING NORTHWARD ACROSS THE ROCKIES FROM NORTHERN
MEXICO INTO SOUTHWEST CANADA...AND A BROAD TROUGH ANCHORED OVER
SOUTHEAST CANADA/THE NORTHEAST CONUS. ON A MORE LOCAL/REGIONAL
LEVEL...THE CWA IS PROGGED TO REMAIN UNDER/NEAR THE MAIN TRACK OF
LOW-AMPLITUDE SHORTWAVE TROUGHS RIPPLING THROUGH THE NORTHWEST
FLOW. STARTING OFF RIGHT AWAY WED EVENING AT 00Z/7PM...ITS
EXPECTED THAT AT LEAST A SMALL PART OF THE CWA SHOULD BE SEEING
ACTIVITY PERSISTING FROM THE LATE AFTERNOON HOURS...ALTHOUGH MODEL
QPF/REFLECTIVITY FIELDS VARY CONSIDERABLY ON THE MOST FAVORED
AREA. AS THE NIGHT WEARS ON...THERE IS A DECENT SIGNAL FOR WARM
AIR ADVECTION/MOISTURE TRANSPORT IN THE 850-700 MILLIBAR
LAYER...WITHIN THE AXIS OF A MODEST 20+KT SOUTHWESTERLY LOW LEVEL
JET. PER THE 12Z/18Z NAM AND LAST FEW SREF RUNS...THIS WOULD FAVOR
EASTERN ZONES FOR THE HIGHEST LATE NIGHT POPS...WHILE THE
ECWMF/GFS WOULD MORE-SO FAVOR CENTRAL/SOUTHWEST ZONES. AS FOR
THUNDERSTORM INTENSITY...ALTHOUGH NOT EXPECTING A WIDESPREAD
NOCTURNAL SEVERE THREAT...CERTAINLY A FEW STRONG TO MARGINALLY
SEVERE STORMS WITH MAINLY A HAIL/LOCALLY HEAVY RAIN THREAT CANNOT
BE RULED OUT GIVEN MUCAPE INCREASING TO AT LEAST 500-1000 J/KG IN
THE PRESENCE OF AROUND 25KT OF DEEP LAYER SHEAR.
THURSDAY/THURSDAY NIGHT...THIS 24 HOURS WOULD APPEAR TO CONTAIN
THE OVERALL-HIGHEST THREAT OF SEVERE STORMS DURING THE NEXT
SEVERAL DAYS...ALTHOUGH THE JURY IS STILL OUT ON WHETHER IT WOULD
BE MORE LOCALIZED OR MORE WIDESPREAD. CERTAINLY WOULD NOT BE
SURPRISED TO SEE THE UPCOMING SPC DAY 2 OUTLOOK INTRODUCE A SLIGHT
RISK FOR ALL/PART OF THE CWA...MAINLY FOR THE AFTERNOON/EVENING
HOURS. IN THE BIG PICTURE...SEASONABLY STRONG/SHARP NORTHWEST FLOW
STRENGTHENS AB IT...AS MODELS ARE IN DECENT AGREEMENT IN DRIVING A
BIT STRONGER/ORGANIZED SHORTWAVE TROUGH SOUTHWARD OUT OF WESTERN
SD ACROSS THE HEART OF CENTRAL NEB/KS. FOR THE MORNING
HOURS...KEPT POPS AT SLIGHT 20S EXCEPT 30S IN THE EAST WHERE
SEEMINGLY THE BEST CHANCE OF LINGERING OVERNIGHT CONVECTION WOULD
BE. THEN HAVE 30 POPS NEARLY ALL AREAS DURING THE AFTERNOON TO
ACCOUNT FOR THUNDERSTORM REDEVELOPMENT AND/OR
RE-INTENSIFICATION...ASSUMING OF COURSE THAT SUFFICIENT HEATING
CAN TAKE PLACE. ITS STILL TOO SOON TO TELL THOUGH WHETHER
POTENTIALLY VIGOROUS AFTERNOON ACTIVITY MAINLY DEVELOPS LOCALLY OR
MOVES IN FROM THE NORTHWEST. AT ANY RATE...THE 18Z NAM DEPICTS A
FAIRLY POTENT NORTHWEST FLOW SEVERE ENVIRONMENT WITH MIXED LAYER
CAPE 2000+ J/KG IN THE PRESENCE OF DECENT 30-40 KNOT DEEP LAYER
SHEAR...MAKING A FEW SUPERCELLS A POSSIBILITY IF THE MESOSCALE
FEATURES COME TOGETHER. FOR THURSDAY EVENING/NIGHT...KEPT 30-50
POPS GOING AREA-WIDE...HIGHEST IN THE FAR SOUTH. NOT ACCOUNTING
FOR POSSIBLE CONVECTIVE EFFECTS...BREEZES DURING THE DAY THURSDAY
ARE EXPECTED TO AVERAGE AROUND 10 MPH FROM THE SOUTH.
FRIDAY/FRIDAY NIGHT...THE LATEST NAM/GFS ARE IN GOOD AGREEMENT
AMPLIFYING THE WESTERN CONUS RIDGE EASTWARD OVER THE CENTRAL
PLAINS...RESULTING IN MODEST HEIGHT RISES AND NEARLY DUE-NORTHERLY
FLOW ALOFT. THIS SHOULD RESULT IN A LESS-FAVORABLE ENVIRONMENT FOR
THUNDERSTORM DEVELOPMENT. HOWEVER...KEPT THE MAJORITY OF THE CWA
WITH SLIGHT POPS DURING THE DAYTIME HOURS MAINLY TO ACCOUNT FOR
POSSIBLE DIURNAL-HEATING INDUCED CONVECTION...BUT LEFT FRIDAY
NIGHT DRY PER PREVIOUS FORECAST.
SATURDAY THROUGH SUNDAY...KEPT THE DRY FORECAST GOING CWA-
WIDE...AS SEEMINGLY-BENIGN NORTHERLY FLOW REMAINS IN PLACE ALOFT
TO THE EAST OF THE ROCKIES-CENTERED RIDGE AXIS. BOTH THE ECWMF/GFS
KEEP THE MAIN BRANCHES OF STRONGER FLOW ALOFT WELL NORTH NEAR THE
CANADIAN BORDER...AND ALSO IN THE SOUTHEAST STATES...WITH THE CWA
ALSO STAYING SAFELY NORTHWEST OF A STALLED...POSSIBLY RETROGRADING
CLOSED MID LEVEL LOW OVER THE SOUTHERN MO/AR AREA ADVERTISED MORE
SO BY THE ECMWF THAN THE GFS. NOT READY TO GUARANTEE A DRY WEEKEND
YET...BUT AT LEAST FOR NOW POPS HAVE BEEN KEPT IN THE SILENT 5-10
RANGE. GIVEN THAT THE AREA HAS SEEN VERY LITTLE IN THE WAY OF NON-
CONVECTIVE BREEZE LATELY...ITS WORTH NOTING THAT THE CURRENT
SUNDAY FORECAST ACTUALLY HAS SUSTAINED SOUTHERLY SPEEDS UP AROUND
15 MPH/GUSTS AROUND 20 MPH.
SUNDAY NIGHT THROUGH TUESDAY MARKS THE RETURN OF VARIOUS...LOW-
CONFIDENCE THUNDERSTORM CHANCES OF THE 20-30 PERCENT
VARIETY...THAT WILL UNDOUBTEDLY BE REFINED SEVERAL TIMES DURING
THE NEXT SEVERAL DAYS. FROM A GENERAL...SYNOPTIC SCALE
STANDPOINT...BOTH THE ECWMF/GFS BREAK DOWN THE RIDGE-DOMINATED
PATTERN FROM THE WEEKEND AND GRADUALLY BRINGS A QUASI-ZONAL
PATTERN AS ONE OR TWO FAIRLY LOW-AMPLITUDE SHORTWAVE TROUGHS OF
NOTE WORK INTO THE CENTRAL PLAINS FROM THE WEST. THIS SHOULD
SUPPORT A CONTINUED SURFACE PATTERN OF LIGHT BUT NOTICEABLY
SOUTHERLY BREEZES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 520 PM CDT TUE AUG 13 2013
THE MAIN CONCERN FOR THE TAF PERIOD IS THE POTENTIAL FOR FOG
TONIGHT...THEN TIMING OF THUNDERSTORMS ON WEDNESDAY. CONVECTION
REMAINS WELL WEST OF THE TERMINAL THIS EVENING AND GENERALLY
EXPECT THE DRY CONDITIONS TO PERSIST UNTIL WEDNESDAY AFTERNOON.
WITH WET GROUND AND DECREASING CLOUDS THIS EVENING...THERE IS SOME
POTENTIAL FOR FOG DEVELOPMENT AND MODELS ARE NOT IN COMPLETE ON
HOW DENSE FOG MAY BE AND HAVE JUST TRENDED WITH MVFR VSBYS TO
START. AN UPPER LEVEL DISTURBANCE WILL CROSS NEB ON WEDNESDAY CHCS
FOR TSTMS INCREASING AGAIN BY MID/LATE AFTN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
401 PM CDT TUE AUG 13 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
WE HAD A MESOSCALE CONVECTIVE VORTEX (MCV) TRACK ACROSS OUR FORECAST
AREA THIS MORNING INTO THE EARLY AFTERNOON HOURS. THIS BROUGHT
WIDESPREAD RAINFALL TO OUR FORECAST AREA AND HAS WORKED OVER THE
ATMOSPHERE ENOUGH THAT ADDITIONAL PRECIPITATION THIS EVENING INTO
TONIGHT IS UNLIKELY. THE CONVECTION THAT TRACKED THROUGH OUR AREA
HAS NOW PASSED SOUTH INTO CENTRAL KANSAS AND NEW STORMS HAVE ALSO
FORMED TO OUR WEST OVER THE HIGH PLAINS OF WESTERN NEBRASKA.
THE WESTERN NEBRASKA THUNDERSTORMS HAVE FORMED ALONG THE LEADING
EDGE OF THE NEXT SHORTWAVE THAT IS TRACKING SOUTHEAST FROM EASTERN
WYOMING/SOUTHWEST SOUTH DAKOTA INTO WESTERN NEBRASKA. DEEP MOISTURE
CONVERGENCE AND AFTERNOON DESTABILIZATION IS ALSO MAXIMIZED ACROSS
WESTERN NEBRASKA INTO THE BLACK HILLS AND THIS IS WHERE ADDITIONAL
THUNDERSTORMS ARE EXPECTED TO FORM THIS EVENING. THIS IS A WEAKLY
SHEARED ENVIRONMENT AND STORM PROPAGATION WILL GENERALLY BE A SLOW
DRIFT TO THE SOUTH...WHICH SHOULD KEEP THE WESTERN STORMS JUST TO
THE WEST OF OUR FORECAST AREA TONIGHT. THERE IS AN OUTSIDE CHANCE OF
OUR WESTERN ZONES SEEING A PREDAWN SHOWER/THUNDERSTORM SHOULD THE
BLACK HILLS CONVECTION MAKE IT THIS FAR SOUTHEAST. HOWEVER...MOST
FORECAST MODEL DATA KEEPS ALL CONVECTION WEST OF OUR FORECAST AREA
TONIGHT AND THUS WE WILL KEEP ALL ZONES DRY TONIGHT...WHILE KEEPING
AN EYE ON THE WEST FOR THE POSSIBILITY OF NEEDING TO THROW SOME POPS
IN THE FORECAST DEPENDING ON FUTURE RADAR TRENDS.
THERE IS SOME POTENTIAL OF FOG TONIGHT GIVEN THE RECENT WIDESPREAD
RAINFALL. HOWEVER...FORECAST MODELS ARE MIXED ON FOG POTENTIAL WITH
THE HRRR MORE FAVORABLE FOR FOG WHILE THE SREF WOULD NOT GIVE US ANY
FOG. ULTIMATELY FOG WILL LARGELY HINGE ON CLOUD COVER AND SUBSEQUENT
COOLING. HAVE LEFT FOG OUT OF THE FORECAST FOR NOW...BUT SHOULD WE
CLEAR OUT AND REMAIN CLEAR THROUGH MOST OF THE NIGHT...THEN COOLING
MIGHT BE ADEQUATE FOR SOME AREAS OF FOG EARLY WEDNESDAY MORNING.
WEDNESDAY...A SHORT WAVE TROUGH WILL TRACK SOUTHEAST ACROSS WESTERN
NEBRASKA. INSTABILITY AND DEEP LAYER SHEAR WILL BE FAIRLY WEAK TO
MODEST AT BEST AND THUS AM NOT EXPECTING SEVERE WEATHER...BUT CAN
NOT RULE OUT A COUPLE OF STRONG THUNDERSTORMS IN ASSOCIATION WITH
PEAK AFTERNOON HEATING. THE BEST CHANCE OF THUNDERSTORMS WILL BE
ACROSS OUR WESTERN ZONES AND TO THE WEST OF OUR FORECAST AREA IN
ASSOCIATION WITH THE APPROACHING SHORTWAVE. TEMPERATURES WILL REMAIN
COOL FOR AUGUST DUE TO A CONTINUATION OF THE COOL AIRMASS
OVERHEAD...CLOUDS...AND POSSIBLE PRECIPITATION. HIGHS WILL GENERALLY
BE IN THE UPPER 70S TO LOWER 80S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 PM CDT TUE AUG 13 2013
THE MAIN HIGHLIGHTS OF THIS 6-DAY PERIOD ARE A CONTINUATION OF
CHALLENGING SHOWER/THUNDERSTORM CHANCES IN THE WED NIGHT THROUGH
FRIDAY TIME FRAME WHICH MIGHT EVEN FEATURE A STRONG-SEVERE STORM
THREAT CENTERED ON THURSDAY...FOLLOWED BY WHAT APPEARS TO BE A
PREDOMINANTLY DRY WEEKEND...AND THEN A RETURN TO VERY UNCERTAIN
RAIN CHANCES IN THE SUNDAY NIGHT-TUESDAY TIME FRAME AS THE PATTERN
CHANGES A BIT. ITS BEEN A TOUGH GO OF IT LATELY TRYING TO
DETERMINE HOW HARD TO HIT...OR BACK OFF...POPS EVEN IN THE FIRST
24 HOURS...SO THESE UNCERTAINTIES CONTINUE TO BE MAGNIFIED EVEN IN
THE DAY 2-3 TIME FRAME. OF HIGHER CONFIDENCE IS THAT A FAIRLY
REMARKABLE RUN OF SUB-90 DEGREE TEMPS WILL CONTINUE...WITH THE
MAJORITY OF THE CWA FORECAST TO TOP OUT IN THE LOW-MID 80S DURING
THIS TIME FRAME...WITH KS ZONES AS USUAL MOST FAVORED TO REACH
UPPER 80S ON A FEW DAYS. AS FOR LOW TEMPS...EVERY NIGHT IS
EXPECTED TO BE FAIRLY SIMILAR AND RATHER UNIFORM ACROSS THE
CWA...EITHER IN THE LOW OR MID 60S.
STARTING OFF WEDNESDAY EVENING/NIGHT...GAVE A BEST-STAB AT TWO
6-HOUR POP BLOCKS HEAVILY BASED ON MET/MAV GUIDANCE BLEND...WITH
THE EVENING PERIOD FEATURING 20S-40S...AND THE LATE NIGHT PERIOD
RANGING FROM ONLY 20S FAR WEST TO 50S IN EASTERN-MOST NEB ZONES.
IN OTHER WORDS...THERE IS A DECENT CHANCE THAT PARTS OF THE CWA
WILL SEE RAIN...BUT CONFIDENCE IN TIMING/PLACEMENT PRECLUDES
LIKELY POPS ANYWHERE YET. ON THE LARGE-SCALE ALOFT...LEGITIMATE
NORTHWEST-FLOW IS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN A
RIDGE AXIS EXTENDING NORTHWARD ACROSS THE ROCKIES FROM NORTHERN
MEXICO INTO SOUTHWEST CANADA...AND A BROAD TROUGH ANCHORED OVER
SOUTHEAST CANADA/THE NORTHEAST CONUS. ON A MORE LOCAL/REGIONAL
LEVEL...THE CWA IS PROGGED TO REMAIN UNDER/NEAR THE MAIN TRACK OF
LOW-AMPLITUDE SHORTWAVE TROUGHS RIPPLING THROUGH THE NORTHWEST
FLOW. STARTING OFF RIGHT AWAY WED EVENING AT 00Z/7PM...ITS
EXPECTED THAT AT LEAST A SMALL PART OF THE CWA SHOULD BE SEEING
ACTIVITY PERSISTING FROM THE LATE AFTERNOON HOURS...ALTHOUGH MODEL
QPF/REFLECTIVITY FIELDS VARY CONSIDERABLY ON THE MOST FAVORED
AREA. AS THE NIGHT WEARS ON...THERE IS A DECENT SIGNAL FOR WARM
AIR ADVECTION/MOISTURE TRANSPORT IN THE 850-700 MILLIBAR
LAYER...WITHIN THE AXIS OF A MODEST 20+KT SOUTHWESTERLY LOW LEVEL
JET. PER THE 12Z/18Z NAM AND LAST FEW SREF RUNS...THIS WOULD FAVOR
EASTERN ZONES FOR THE HIGHEST LATE NIGHT POPS...WHILE THE
ECWMF/GFS WOULD MORE-SO FAVOR CENTRAL/SOUTHWEST ZONES. AS FOR
THUNDERSTORM INTENSITY...ALTHOUGH NOT EXPECTING A WIDESPREAD
NOCTURNAL SEVERE THREAT...CERTAINLY A FEW STRONG TO MARGINALLY
SEVERE STORMS WITH MAINLY A HAIL/LOCALLY HEAVY RAIN THREAT CANNOT
BE RULED OUT GIVEN MUCAPE INCREASING TO AT LEAST 500-1000 J/KG IN
THE PRESENCE OF AROUND 25KT OF DEEP LAYER SHEAR.
THURSDAY/THURSDAY NIGHT...THIS 24 HOURS WOULD APPEAR TO CONTAIN
THE OVERALL-HIGHEST THREAT OF SEVERE STORMS DURING THE NEXT
SEVERAL DAYS...ALTHOUGH THE JURY IS STILL OUT ON WHETHER IT WOULD
BE MORE LOCALIZED OR MORE WIDESPREAD. CERTAINLY WOULD NOT BE
SURPRISED TO SEE THE UPCOMING SPC DAY 2 OUTLOOK INTRODUCE A SLIGHT
RISK FOR ALL/PART OF THE CWA...MAINLY FOR THE AFTERNOON/EVENING
HOURS. IN THE BIG PICTURE...SEASONABLY STRONG/SHARP NORTHWEST FLOW
STRENGTHENS AB IT...AS MODELS ARE IN DECENT AGREEMENT IN DRIVING A
BIT STRONGER/ORGANIZED SHORTWAVE TROUGH SOUTHWARD OUT OF WESTERN
SD ACROSS THE HEART OF CENTRAL NEB/KS. FOR THE MORNING
HOURS...KEPT POPS AT SLIGHT 20S EXCEPT 30S IN THE EAST WHERE
SEEMINGLY THE BEST CHANCE OF LINGERING OVERNIGHT CONVECTION WOULD
BE. THEN HAVE 30 POPS NEARLY ALL AREAS DURING THE AFTERNOON TO
ACCOUNT FOR THUNDERSTORM REDEVELOPMENT AND/OR
RE-INTENSIFICATION...ASSUMING OF COURSE THAT SUFFICIENT HEATING
CAN TAKE PLACE. ITS STILL TOO SOON TO TELL THOUGH WHETHER
POTENTIALLY VIGOROUS AFTERNOON ACTIVITY MAINLY DEVELOPS LOCALLY OR
MOVES IN FROM THE NORTHWEST. AT ANY RATE...THE 18Z NAM DEPICTS A
FAIRLY POTENT NORTHWEST FLOW SEVERE ENVIRONMENT WITH MIXED LAYER
CAPE 2000+ J/KG IN THE PRESENCE OF DECENT 30-40 KNOT DEEP LAYER
SHEAR...MAKING A FEW SUPERCELLS A POSSIBILITY IF THE MESOSCALE
FEATURES COME TOGETHER. FOR THURSDAY EVENING/NIGHT...KEPT 30-50
POPS GOING AREA-WIDE...HIGHEST IN THE FAR SOUTH. NOT ACCOUNTING
FOR POSSIBLE CONVECTIVE EFFECTS...BREEZES DURING THE DAY THURSDAY
ARE EXPECTED TO AVERAGE AROUND 10 MPH FROM THE SOUTH.
FRIDAY/FRIDAY NIGHT...THE LATEST NAM/GFS ARE IN GOOD AGREEMENT
AMPLIFYING THE WESTERN CONUS RIDGE EASTWARD OVER THE CENTRAL
PLAINS...RESULTING IN MODEST HEIGHT RISES AND NEARLY DUE-NORTHERLY
FLOW ALOFT. THIS SHOULD RESULT IN A LESS-FAVORABLE ENVIRONMENT FOR
THUNDERSTORM DEVELOPMENT. HOWEVER...KEPT THE MAJORITY OF THE CWA
WITH SLIGHT POPS DURING THE DAYTIME HOURS MAINLY TO ACCOUNT FOR
POSSIBLE DIURNAL-HEATING INDUCED CONVECTION...BUT LEFT FRIDAY
NIGHT DRY PER PREVIOUS FORECAST.
SATURDAY THROUGH SUNDAY...KEPT THE DRY FORECAST GOING CWA-
WIDE...AS SEEMINGLY-BENIGN NORTHERLY FLOW REMAINS IN PLACE ALOFT
TO THE EAST OF THE ROCKIES-CENTERED RIDGE AXIS. BOTH THE ECWMF/GFS
KEEP THE MAIN BRANCHES OF STRONGER FLOW ALOFT WELL NORTH NEAR THE
CANADIAN BORDER...AND ALSO IN THE SOUTHEAST STATES...WITH THE CWA
ALSO STAYING SAFELY NORTHWEST OF A STALLED...POSSIBLY RETROGRADING
CLOSED MID LEVEL LOW OVER THE SOUTHERN MO/AR AREA ADVERTISED MORE
SO BY THE ECMWF THAN THE GFS. NOT READY TO GUARANTEE A DRY WEEKEND
YET...BUT AT LEAST FOR NOW POPS HAVE BEEN KEPT IN THE SILENT 5-10
RANGE. GIVEN THAT THE AREA HAS SEEN VERY LITTLE IN THE WAY OF NON-
CONVECTIVE BREEZE LATELY...ITS WORTH NOTING THAT THE CURRENT
SUNDAY FORECAST ACTUALLY HAS SUSTAINED SOUTHERLY SPEEDS UP AROUND
15 MPH/GUSTS AROUND 20 MPH.
SUNDAY NIGHT THROUGH TUESDAY MARKS THE RETURN OF VARIOUS...LOW-
CONFIDENCE THUNDERSTORM CHANCES OF THE 20-30 PERCENT
VARIETY...THAT WILL UNDOUBTEDLY BE REFINED SEVERAL TIMES DURING
THE NEXT SEVERAL DAYS. FROM A GENERAL...SYNOPTIC SCALE
STANDPOINT...BOTH THE ECWMF/GFS BREAK DOWN THE RIDGE-DOMINATED
PATTERN FROM THE WEEKEND AND GRADUALLY BRINGS A QUASI-ZONAL
PATTERN AS ONE OR TWO FAIRLY LOW-AMPLITUDE SHORTWAVE TROUGHS OF
NOTE WORK INTO THE CENTRAL PLAINS FROM THE WEST. THIS SHOULD
SUPPORT A CONTINUED SURFACE PATTERN OF LIGHT BUT NOTICEABLY
SOUTHERLY BREEZES.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z WEDNESDAY
AFTERNOON) ISSUED AT 1245 PM CDT TUE AUG 13 2013
THE RAIN IS ON THE WAY OUT OF KGRI AND EXPECT VISIBILITY AND
CEILINGS WILL IMPROVE INTO VFR RANGE BETWEEN 18Z AND 19Z. DRY
WEATHER IS LIKELY THROUGH THE REMAINDER OF THE TAF PERIOD WITH
LIGHT WINDS. THE WIND DIRECTION WILL GENERALLY BE VARIABLE THROUGH
TONIGHT AND THEN SHOULD BECOME PREDOMINATELY SOUTHERLY BY EARLY
TOMORROW MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...PFANNKUCH
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
327 PM EDT TUE AUG 13 2013
.SYNOPSIS...
AHEAD OF A COLD FRONT THAT WILL TRACK SLOWLY THROUGH CENTRAL NORTH
CAROLINA TONIGHT...A LEE SURFACE TROUGH WILL SHARPEN IN THE LEE OF
THE APPALACHIANS THIS AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE
MIDDLE ATLANTIC REGION...WHILE THE FRONT STALLS AND BECOMES
QUASI-STATIONARY ALONG THE CAROLINA COAST...MID TO LATE WEEK
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 325 PM TUESDAY...
THE NORTHWEST FRINGE OF AN AREA OF SCATTERED SHOWERS AND
STORMS...FROM NEAR KVUJ TO KRDU TO KIXA...ROUGHLY CORRESPONDED AT
19Z TO A DIFFERENTIAL HEATING BOUNDARY ALONG AN EARLIER MID LEVEL
CLOUD SHIELD ASSOCIATED WITH A LEAD IMPULSE STRETCHING FROM SE VA TO
THE SC UPSTATE. MEANWHILE...A SECOND AREA OF SHOWERS AND STORMS
CONTINUED TO BECOME BETTER ORGANIZED ALONG A LEE SURFACE TROUGH/
CONVERGENCE AXIS OVER WESTERN NC AND SW VA...AND IN ADVANCE OF A
STRONGER MID LEVEL IMPULSE ROUGHLY ALIGNED ALONG THE CENTRAL-
SOUTHERN APPALACHIANS. THE HRRR SUGGESTS THIS LATTER ACTIVITY WILL
WEAKEN...BUT THIS SEEMS TO BE IN ERROR SINCE THE AGGREGATE COLD POOL
HAS BECOME INCREASINGLY ORGANIZED AS IT PROPAGATES INTO AN
INCREASINGLY UNSTABLE AIR MASS WITH TIME AND EASTWARD EXTENT
DOWNSTREAM OVER CENTRAL NC. AS SUCH...THE MOST LIKELY SCENARIO IS
THAT SCATTERED MAINLY MULTI-CELLULAR ACTIVITY WILL CONTINUE TO
PERCOLATE OVER CENTRAL NC BEFORE THE AFOREMENTIONED WESTERN NC LINE
IMPACTS A LARGER PERCENTAGE OF THE POPULATION AS IT CONTINUES
SOUTHEASTWARD THROUGH THE EVENING HOURS.
WHILE MULTI-CELL CLUSTERS SHOULD BE THE DOMINANT CONVECTIVE MODE
WITH AN ASSOCIATED PRIMARY THREAT OF MARGINALLY SEVERE WIND
GUSTS...SEASONABLY STRONG MID LEVEL FLOW ON THE ORDER OF 30-40 KTS
(STRONGEST NORTH) PER 12Z RAOB AND MORE RECENT REGIONAL VWP
DATA...WILL ALSO SUPPORT AT LEAST TRANSIENT SUPERCELLS...
PARTICULARLY OVER THE NORTHERN COASTAL PLAIN AND NORTHEAST
PIEDMONT...WHERE BOTH BUOYANCY AND BULK SHEAR WILL BE RELATIVELY
MAXIMIZED. SEVERE WIND...AS WELL AS HAIL OWING TO DYNAMIC PRESSURE
EFFECTS...WOULD BE ENHANCED WITH ANY SUCH SUPERCELLULAR MODE.
RELATIVELY LONG AND STRAIGHT CURRENT AND FORECAST HODOGRAPHS SUGGEST
A FEW STORM SPLITS WILL BE PROBABLE...WITH AN OTHERWISE WSW MEAN
WIND VECTOR/STORM MOTION.
SCATTERED TO NUMEROUS SHOWER AND STORM COVERAGE SHOULD DIMINISH FROM
WEST TO EAST THROUGH MIDNIGHT. HOWEVER...A FEW WIDELY SCATTERED
SHOWERS AND ISOLATED STORMS WILL BE POSSIBLE ALONG THE SYNOPTIC COLD
FRONT - ONE STILL WELL WEST OF OUR REGION OVER THE EASTERN TN VALLEY
AT 16Z - AS IT PASSES SLOWLY THROUGH OUR REGION OVERNIGHT. THERE MAY
EVEN BE A LITTLE ANAFRONTAL LIGHT RAIN TOWARD THE FAR SOUTHEAST
REACHES OF THE CWFA AROUND DAYBREAK...AS THE MID-UPPER TROUGH AXIS
SHARPENS OVERHEAD. SINCE NWP GUIDANCE IS TYPICALLY TOO
FAST/AGGRESSIVE WITH FRONTAL PASSAGES...ESPECIALLY THIS TIME OF
YEAR...A CONTINUED VERY HUMID BOUNDARY LAYER OVER AT LEAST THE
EASTERN THIRD OF THE CWFA FOR MUCH OF THE NIGHT WILL SUPPORT AREAS
OF STRATUS AND FOG...PARTICULARLY IF MID LEVEL CLOUDINESS CLEARS
SUFFICIENTLY IN THE WAKE OF THE EARLIER CONVECTION. LOWS IN THE
UPPER 60S TO MIDDLE 70S.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 PM TUESDAY...
THOUGH THE LOW LEVEL FRONTAL ZONE AND ASSOCIATED CHANCE OF SHOWERS
AND STORMS SHOULD HAVE MOVED TO SOUTHEASTERN NC BY EARLY WED...NWP
CROSS SECTIONS SUGGEST POST-FRONTAL HIGH-BASED STRATOCUMULUS WILL
MAINTAIN MOSTLY CLOUDY CONDITIONS GENERALLY EAST OF I-95 THROUGH
MIDDAY...WITH CONSIDERABLE CIRRUS LINGERING THROUGHOUT THE
AFTERNOON. PARTLY TO MOSTLY SUNNY CONDITIONS SHOULD RULE ELSEWHERE.
SURFACE HIGH PRESSURE AND ASSOCIATED NORTH NORTHEASTERLY LOW LEVEL
FLOW...WHICH WILL GUST TO NEAR 20 MPH IN THE I-95 CORRIDOR
LATE-MORNING TO EARLY AFTERNOON...WILL RESULT IN MILDER CONDITIONS
AND MUCH LOWER HUMIDITY VALUES AS SURFACE DEWPOINTS DIP INTO THE 50S
ACROSS THE PIEDMONT - HIGH TEMPERATURES RANGING FROM THE UPPER 70S
TO NEAR 80 OVER THE NORTHERN COASTAL PLAIN...TO LOW-MID 80S SOUTHERN
PIEDMONT AND WESTERN SANDHILLS. LINGERING BUT THINNING CIRRUS
OVERNIGHT...WITH LOWS 60 TO 65 DEGREES...EXCEPT 55 TO 60 IN RURAL
PIEDMONT LOCATIONS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...
THE MODELS STILL SHOW SOME VARIABILITY AS TO WHERE THE COLD FRONT
WILL STALL. THE GFS BRINGS THE FRONT ALMOST COMPLETELY THROUGH NC...
KEEPING THE REGION DRIER THAN OTHER MODELS FOR THE REST OF THE WEEK.
THE ECMWF DOES NOT PUSH THE FRONT AS FAR SUGGESTING THAT
THE SOUTHERN AND EASTERN PORTION OF NC COULD SEE A MUCH HIGHER QPF.
AS POINTED TO IN PREVIOUS DISCUSSIONS... HIGH SURFACE PRESSURE IN
THE NORTHEAST COULD ALLOW FOR A WARM SEASON CAD TO FORM IN THE LEE
OF THE APPALACHIANS WITH A WEDGE FRONT DRAPED ACROSS CENTRAL NC LATE
IN THE WEEK. HOW FAR THE FRONT WILL PROPAGATE REMAINS A TOPIC OF
DISCUSSION AS THE GFS PUSHES THIS FRONT ALL THE WAY THROUGH NC WITH
THE ECMWF DEPICTING A SHARPER...POSSIBLY MORE REALISTIC...BOUNDARY
SETTING UP JUST EAST OF THE FOOTHILLS AND ACROSS THE WESTERN
PIEDMONT. LOW PRESSURE IN THE GULF SHOULD ALSO BRING HIGH THETA-E
PARCELS UP THE EAST COAST CREATING VERY MOIST CONDITIONS FOR THE
WEEKEND.
THE FRONT WILL BEGIN TO STALL OVER EASTERN NC ON THURSDAY. MODEL
UNCERTAINTY IN THE EXACT LOCATION OF WHERE THE FRONT WILL STALL WILL
AFFECT QPF AMOUNTS WITH THE GFS CONFINING PRECIP TO THE COAST
WHEREAS THE ECMWF SETS UP THE FRONT CLOSER TO THE I-95 CORRIDOR.
CLIMATOLOGY AND NORMAL DIURNAL PROCESSES WOULD SUGGEST THAT THE
ECMWF SOLUTION WOULD BE FAVORED AT THIS TIME AND AT LEAST SOME QPF
WOULD BE REALIZED EAST OF I-95.
AS CAD CONDITIONS LOCK IN ON FRIDAY AND SATURDAY...SEVERAL SHORTWAVE
IMPULSES WILL TRAIN UP THE SOUTHEAST COAST PROVIDING BETTER DYNAMICS
FOR HEAVIER RAINFALL...AT LEAST FROM THE TRIANGLE EASTWARD...WITH
MORE OVERRUNNING PRECIP IN THE NORTHWEST DUE TO ISENTROPIC LIFT. IF
THE WEDGE FRONT IS PINNED BACK FARTHER TO THE WEST...THEN THE
POSSIBILITY FOR SEVERE STORMS IN THE EASTERN PORTION OF THE CWA
BECOMES GREATER BUT MODELS ARE STARTING TO DOWNPLAY THIS SCENARIO
AND SHOW MORE OF A NORTHEASTERLY FLOW REGIME FOR MOST OF THE AREA
WITH LITTLE LOW-LEVEL SHEAR OR HELICITY AVAILABLE THROUGH SUNDAY
MORNING. THIS STARTS TO CHANGE A BIT ON SUNDAY AFTERNOON AS AT LEAST
KFAY AND KRWI BEGIN TO SWITCH BACK TO A SOUTHERLY FLOW REGIME. MODEL
FORECAST SOUNDINGS SHOW THAT BY THE TIME DESTABILIZATION OCCURS BOTH
SITES COULD HAVE SOUTHWESTERLY FLOW KEEPING BULK SHEER (PRIMARILY
SPEED SHEER) DOWN TO 20 KNOTS OR SO WITH CLOSE TO 1000 J/KG OF
INSTABILITY. WHILE HEAVY RAIN AND FLOODING WOULD BE THE PRIMARY
THREAT...SMALL INVERTED-V SIGNATURES SUGGEST THAT WINDS COULD BE A
POSSIBLE SECONDARY THREAT. AS AN ASIDE THE NHC IS STILL NOT BUYING
INTO THE TROPICAL SYSTEM THAT THE GFS IS SPINNING UP IN THE NORTHERN
GULF ON FRIDAY EVENING DUE TO UNFAVORABLE UPPER LEVEL CONDITIONS.
THAT BEING SAID A ECMWF SOLUTION OF A MORE CONSTANT FLOW OF MOISTURE
OUT OF THE GULF IS MORE LIKELY WITH SMALLER SHORTWAVE IMPULSES
ENHANCING THE FLOW.
THE PRESENCE OF THE SAME MOIST AIR MASS WILL CONTINUE TO PRODUCE
UNSETTLED CONDITIONS WITH MORE PRECIPITATION INTO EARLY NEXT WEEK
ALTHOUGH THERE IS A FAIR AMOUNT OF MODEL UNCERTAINTY AT THE END OF
THE LONG TERM DEPENDING ON HOW EVENTS UNFOLD THIS WEEKEND. WILL KEEP
AT LEAST CHANCE POPS THROUGH THE END OF THE PERIOD.
TEMPERATURES IN THE LOW TO MID 80S ON WEDNESDAY SHOULD DROP IN TO
THE UPPER 70S FOR MUCH OF THE PERIOD DUE TO THE FRONTAL PASSAGE AND
POTENTIAL CAD. THICKNESS VALUES AS LOW AS 1370 IN THE TRIAD ARE
VALUES TYPICALLY SEEN IN EARLY MAY AS OPPOSED TO THE MIDDLE OF
AUGUST. HIGH DEWPOINTS SHOULD ALLOW FOR THE MIN TEMP TO REMAIN
AROUND NORMAL IN THE MID 60S. A WARMING TREND SHOULD ALLOW FOR MAX
TEMPS TO REACH THE UPPER 80S AND MIN TEMPS IN TO THE UPPER 60S BY
THE END OF THE PERIOD...WITH HIGHEST TEMPS IN THE SE AND REMAINING
COOLER IN THE NORTHWEST PIEDMONT.
&&
.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
AS OF 220 PM TUESDAY...
SCATTERED SHOWERS AND STORMS THIS AFTERNOON WILL BECOME MORE
NUMEROUS...LIKELY IN THE FORM OF A BROKEN LINE THAT WAS DEVELOPING
OVER NW NC AND SW VA AS OF 18Z. THESE SHOWERS AND STORMS - AND
ASSOCIATED SUB-VFR CONDITIONS AND GUSTY WINDS - ARE LIKELY TO
IMPACT...FROM NORTHWEST TO SOUTHEAST...THE TRIAD TERMINALS TO KRDU
AND KRWI BETWEEN 20Z AND 02Z. THERE WILL REMAIN A LINGERING CHANCE
OF A SHOWER OR STORM UNTIL A COLD FRONT SLOWLY CROSSES OUR REGION
TONIGHT. IN ADDITION...AREAS OF FOG OR LOW STRATUS WILL BE
PROBABLE...MAINLY AT EASTERN TERMINALS...WHERE THE FRONTAL PASSAGE
WILL LIKELY BE DELAYED UNTIL AROUND SUNRISE. SOUTHWEST WINDS AHEAD
OF THE FRONT WILL VEER TO NORTHWESTERLY...THEN NORTH NORTHEASTERLY
WITH GUSTS OF 15-20 KTS...LATE MORNING TO EARLY AFTERNOON WED.
LOOKING AHEAD: A WAVE OF LOW PRESSURE WILL DEVELOP ALONG A FRONTAL
ZONE STALLED ALONG THE SOUTHEAST US COAST...AND RESULT IN A CHANCE
OF SUB-VFR CONDITIONS AND RAIN LATE WEEK-EARLY THIS WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...ELLIS/CR
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
303 PM EDT TUE AUG 13 2013
.SYNOPSIS...
A FRONT WILL APPROACH THE AREA TONIGHT AND MOVE THROUGH EASTERN
NORTH CAROLINA AROUND SUNRISE WEDNESDAY. FRONT WILL STALL ALONG
THE COAST THROUGH THE REMAINDER OF THE WEEK AND THE WEEKEND AS
WAVES OF LOW PRESSURES MOVE ALONG IT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 152 PM TUE...MODELS IN DECENT AGREEMENT ON TIMING OF
APPROACHING FRONT WITH NAM BEING A COUPLE OF HOURS SLOWER IN
BRINGING FRONT THROUGH EASTERN NORTH CAROLINA. HRRR HAS GOOD HANDLE
ON DEVELOPING ACTIVITY THIS AFTERNOON (RUC AND WRF NOT SHOWING ANY
PRECIP FOR THE NEXT FEW HOURS)...AND INDICATES AN INCREASE IN
COVERAGE AFTER SUNSET. BROAD UPPER TROUGH OVER THE EAST WITH A
SERIES OF WEAK MID-LEVEL PIECES OF ENERGY ROTATING AROUND IT WILL
KEEP THE FORECAST PERIOD UNSETTLED. FORECAST SOUNDINGS SHOWING
CAPES INCREASING OVERNIGHT FROM 2K TO AROUND 3.5K WITH LIS AROUND
-5 AND PWS OVER 2 INCHES. WILL HAVE A CONTINUING CHANCE OF
THUNDERSTORMS OVER NIGHT...SOME OF WHICH COULD HAVE HEAVY RAIN
WITH LOCALIZED FLOODING IN THE MODERATE MID LEVEL LAYER FLOW AND
HIGH PWS. FRONT WILL ENTER THE COASTAL PLAINS BEFORE SUNRISE.
&&
.SHORT TERM /WEDNESDAY/...
AS OF 155 PM TUE...FRONT WILL MOVE THROUGH THE COASTAL AREAS AROUND
MID MORNING. DRIER COOLER ATMOSPHERE WILL MOVE OVER THE AREA WITH
HIGH TEMPERATURES IN THE LOWER TO MIDDLE 80S IN THE NORTHERLY
FLOW...AND A DECREASE IN CLOUD COVER.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS OF 3 PM TUE...BELOW NORMAL TEMPS AND ABOVE NORMAL PRECIP
EXPECTED THROUGH THE PERIOD. A FRONT WILL STALL OFF THE NC COAST
WED NIGHT THROUGH THE WEEKEND WITH AREAS OF LOW PRESSURE MOVING
ALONG THE BOUNDARY...AND SFC HIGH PRESSURE BUILDING NORTH OF THE
AREA. ONLY SIG CHANGE TO PREVIOUS FORECAST WAS TO TRIM POPS BACK
SLIGHTLY...WITH MODELS NOW COMING IN QUITE A BIT DRIER WED NIGHT
INTO FRI...ESP FOR AREAS IN THE NORTHERN TIER. COULD SEE A SHARP
PRECIP GRADIENT SET UP WED NIGHT THROUGH FRI...WHERE BEST PRECIP
CHANCES WILL BE ALONG THE COAST AND SOUTHERN TIER. FRONT WILL
LIKELY MOVE CLOSER TO THE COAST FRI INTO THE WEEKEND WITH WEAK
WAVES MOVING ALONG IT. WILL CONTINUE HIGH CHANCE POPS THIS
WEEKEND. LOW LEVEL THICKNESS VALUES...NELY FLOW AND ABUNDANT CLOUD
COVER AND PRECIP SUPPORT HIGH TEMPS IN THE UPPER 70S TO LOWER 80S
THROUGH THE WEEKEND...WITH OVERNIGHT LOWS IN THE MID 60S/LOWER
70S. MODEL DIFFERENCES CONTINUE EARLY NEXT WEEK BTWN
GFS/ECMWF...BUT AT THIS TIME IT LOOKS LIKE SLY FLOW WILL
RETURN...WITH TEMPS SLOWLY WARMING AS UPPER RIDGE BEGINS TO
REBUILD OVER THE SE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH 18Z WEDNESDAY/...
AS OF 1245 PM TUE...SHOWERS AND THUNDERSTORMS HAVE FORMED OVER
EASTERN NORTH CAROLINA THIS AFTERNOON...AND COVERAGE IS EXPECTED
TO INCREASE THROUGH THE DAY. WILL HAVE MVFR WITH OCCASIONAL IFR IN
CIG AND VIS WITH THESE STORMS. BROKEN LINE OF STORMS AHEAD OF
APPROACHING FRONT IS EXPECTED TO MOVE THROUGH THE AREA AFTER
SUNSET. DECREASED COVERAGE AFTER MIDNIGHT BUT WILL HAVE SOME
STRATUS FORMING. FRONTAL PASSAGE EXPECTED AROUND SUNRISE WITH WIND
SHIFTING TO NORTH NORTHEASTERLY.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM TUE...FRONT WILL STALL OFF THE NC COAST WED NIGHT
THROUGH LATE WEEK WITH AREAS OF LOW PRESSURE MOVING ALONG IT.
PERIODS OF SUB-VFR CONDITIONS LIKELY WED NIGHT THROUGH THE WEEKEND
WITH PRED NELY FLOW AND GOOD MOISTURE. SCT SHOWERS AND ISO TSTMS
EXPECTED EACH DAY.
&&
.MARINE...
SHORT TERM /THROUGH WEDNESDAY/...
AS OF 159 PM TUE...SOUTHWEST FLOW WILL INCREASE TO AROUND 20 KNOTS
THIS EVENING AS GRADIENT INCREASES IN ADVANCE OF APPROACHING FRONT.
MAY SEE SOME GUSTS TO 25 KNOTS AND SEAS COULD REACH 6 FEET IN THE
CENTRAL OUTER WATERS. THEREFORE WILL KEEP SCA UP. STRONG STORMS ARE
POSSIBLE THROUGH MUCH OF THE NIGHT WITH GUSTY WINDS AND HEAVY RAIN.
FRONT EXPECTED TO MOVE THROUGH THE WATERS DURING THE MORNING
WEDNESDAY WITH WIND SHIFTING TO NORTH NORTHEASTERLY AND DIMINISHING
IN SPEED TO AROUND 15 KNOTS. SEAS WILL DROP TO 3 TO 4 FEET WEDNESDAY.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 3 PM TUE...FRONT WILL STALL OFF THE NC COAST WED NIGHT
THROUGH THE WEEKEND WITH WAVES OF LOW PRESSURE MOVING ALONG IT.
A PERIOD OF MODERATE NE FLOW 10-20KT IS EXPECTED TO CONTINUE WED
NIGHT INTO THU NIGHT WITH SEAS UP TO 5FT...THEN DIMINISH TO
10-15KT FRI WITH SEAS 2-4FT. CONFIDENCE IS LOW REGARDING WIND
DIRECTIONS FOR THIS WEEKEND...AS MODELS CONTINUE TO DIFFER
HANDLING EXACT PLACEMENT OF FRONT IN COASTAL WATERS. THOUGH EXPECT
WINDS AOB 15KT THIS WEEKEND WITH SEAS 2-3FT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ152-154.
&&
$$
SYNOPSIS...CGG/CQD
NEAR TERM...CGG
SHORT TERM...CGG
LONG TERM...CQD
AVIATION...CGG/CQD
MARINE...CGG/CQD
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
203 PM MDT TUE AUG 13 2013
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 201 PM MDT TUE AUG 13 2013
WATER VAPOR IMAGERY CONTINUES TO SHOW BLOCKING PATTERN ACROSS THE
CONUS WITH UPPER RIDGING CENTERED ACROSS THE ROCKIES INTO THE HIGH
PLAINS. SURFACE ANALYSIS SHOWS HIGH PRESSURE ACROSS THE DAKOTAS
WITH THE FRONTAL BOUNDARY STRETCHED ACROSS CENTRAL SD. STORMS HAVE
STARTED FIRING ACROSS NORTHWEST SD INTO THE BLACK HILLS AREA WITH
A COUPLE SEVERE AT THIS TIME. STORMS WILL CONTINUE TO DEVELOP OVER
THE NEXT FEW HOURS OVER THE AREA. THE BEST INSTABILITY IS ACROSS
SE MONTANA THROUGH WESTERN SD WITH MLCAPE OF 2000 TO 2500 J/KG.
LOW LEVEL SHEAR IS OVERALL WEAK...BUT IS BEST ACROSS NW SD. WITH
DEEP INSTABILITY...ENOUGH SHEAR FOR CONTINUED SUPERCELL
DEVELOPMENT INTO THIS EVENING...AND PERHAPS AN ISOLATED SEVERE
STORM THROUGH THE OVERNIGHT HOURS. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS TODAY AND TONIGHT. STORMS WILL AGAIN BE SLOW
MOVING AND HAVE THE POTENTIAL FOR PRODUCING LOCALLY HEAVY
RAINFALL.
LITTLE CHANGE TO THE OVERALL PATTERN TOMORROW WITH UPPER RIDGING
AXIS WEST OF THE AREA. LINGERING STORMS ARE POSSIBLE ACROSS THE AREA
TOMORROW MORNING...BUT A REDEVELOPMENT OF STORMS ARE EXPECTED IN THE
AFTERNOON. INSTABILITY IS PROGGED TO BE WEAKER TOMORROW...WITH
RELATIVELY WEAK SHEAR CONTINUING. SUBTLE WAVES WILL HELP TRIGGER
CONVECTION...BUT ASIDE FOR AN ISOLATED SEVERE STORM OR TWO...SEVERE
WEATHER IS NOT EXPECTED. WEAK STEERING WINDS WILL AGAIN RESULT IN
SLOW STORM MOTION.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 201 PM MDT TUE AUG 13 2013
MEAN WESTERN NOAM RIDGING TO REMAIN IN THE PERIOD...WITH DOWNSTREAM
MEAN NEGATIVE HEIGHT ANOMALIES LINGERING BUT WEAKENING IN THE
EASTERN NOAM. PATTERN CHANGE WILL OCCUR AS THE NE PAC PERSISTENT
UPPER TROUGH IS FORECAST TO CYCLE...WITH UPPER RIDGING EXPECTED OVER
THE NORTHERN PLAINS FRIDAY THROUGH MUCH OF NEXT WEEK. MID LEVEL
TROUGH AND ASSOCIATED SFC REFLECTION STILL ON TRACK TO PROGRESS
THROUGH THE REGION SUNDAY/SUNDAY NIGHT...WITH CONTINUED CHANCES FOR
SHRA/TS THEN. OTHERWISE...HAVE KEPT THE REMAINDER OF THE PERIOD
DRY...SAVE FOR THIS THUR WHEN THE LAST IN A SERIES OF DISTURBANCES
WILL EXIT THE REGION. FAIRLY WARM TEMPS EXPECTED AS THE UPPER RIDGE
TILTS OVER THE REGION SAT-SUN...THEN AGAIN TUESDAY WITH A RESURGENCE
OF THE WESTERN NOAM RIDGE. THERE IS SOME LINGERING UNCERTAINTY TO
HOW FAR EAST AND NORTH THE UPPER RIDGE WILL BUILD...WHICH WILL HAVE
A LARGE IMPACT OF LOCAL TEMPS/MOISTURE. DOWNSTREAM DEVELOPMENTS WILL
ALSO HAVE AN EFFECT ON THIS PROCESS...MAINLY BEING IF THE PERSISTENT
EASTERN NOAM TROUGH RETURNS...HINTED AT IN THE ECMWF NEXT WEEK
BEYOND THE CURRENT FORECAST PERIOD. BEFORE THE NEXT PATTERN IS
ESTABLISHED...SLIGHTLY PROGRESSIVE FLOW/WARMER TEMPS/AND DECREASING
LL MOISTURE LOOKS PROBABLE IN THE PERIOD. HAVE OPTED TO SIDE ON THE
WARMER SIDE OF MIDDLE GUIDANCE NUMBERS GIVEN THE DIRER
PATTERN...WHICH LOOKS TO REMAIN THROUGH MUCH OF THE PERIOD ATTM.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON
ISSUED AT 201 PM MDT TUE AUG 13 2013
VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD SAVE IN AN
NEAR SCT TS THIS AFTERNOON AND TONIGHT. MVFR/IFR CIGS WILL BE
POSSIBLE ONCE AGAIN TOWARD DAWN OVER THE EASTERN FA...WITH
EASTERLY FLOW POSSIBLY PUSHING STRATUS BACK INTO THE EASTERN BH
FOOTHILLS TUE MORNING. DID HINT AT THIS IN THE RAP TAF.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...13
LONG TERM...JC
AVIATION...JC
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
346 PM CDT TUE AUG 13 2013
.DISCUSSION...
MUCH CONVECTIVE ACTIVITY OCCURRING ALONG A NORTHERN TEXAS (QUASI)
STATIONARY BOUNDARY THAT MAY EVENTUAL IMPACT OUR NORTH(EAST)ERN
COUNTIES WITHIN THE NEXT 4 TO 6 HOURS. A VERY HEATED AND MOIST
DOWNSTREAM AIR MASS FOR THIS STATIONARY BOUNDARY...OR SUBSEQUENT
CONVECTIVE OUTFLOW...TO WORK WITH IN THE COMING 24-36 HOURS.
THERE IS STILL SUBSIDENCE TO WORK WITH AS THERE HAVE BEEN RECENT
HEIGHT RISES AND A FEW DEGREES OF WARMTH AT THE 85-7H LEVELS...BUT
THE UPPER LEVELS REMAIN FAIRLY DIFFULENT AS EAST TEXAS FALLS WITHIN
A (RELATIVELY) MILD MID-UPPER LEVEL HEIGHT WEAKNESS BETWEEN DESERT
SOUTHWEST AND FLORIDA-CENTERED RIDGING.
ALL OF THE THERMODYNAMIC INDICES ARE THERE TO SUPPORT RETURNING
SCATTERED SHOWERS AND STORMS BEGINNING AS EARLY AS MID-WEDNESDAY
MORNING. K-INDICES AROUND 40...L.I. IN THE -5 REALM...AND ABOVE
1 K J/KG CAPES FROM THE GFS/NAM PROGS OVER THE NORTHERN CWA
INCREASE THE SHOWER/STORM PROBABILITY. YES...THERE WILL BE SOME
SUBSIDENCE TO DEAL WITH...BUT WITH A CONSISTENT RUN-TO-RUN THEME
OF INTRODUCING WEAK LOWER MS VALLEY TROUGHING (AND WITNESSING WHAT
IS ONGOING ACROSS DFW`S FA)...HAD TO BITE ON THE LIKELY SIDE OF
POPS. GREATER THAN 2 INCH PWATS WILL POOL ALONG `A` BOUNDARY...WHETHER
THAT BE MORE OF A SYNOPTIC OR A SERIES OF MESOSCALE (UPSTREAM
OUTFLOW) BOUNDARIES. OTHER THAN SUBSIDENCE AS A RAIN INHIBITER...THE
ONLY OTHER NEGATIVE TO MORE WIDESPREAD COVERAGE WOULD BE THAT THE
REGION DOES FALL INTO MORE OF A RR QUAD OF THE JET (ALTHOUGH 25-3H
FLOW REMAINS DIFFULENT).
NEEDLESS TO SAY...BUT WHAT EVOLVES TOMORROW WILL DRIVE THURSDAY`S
FORECAST. SINCE THE FORECAST IS MORE WET TOMORROW...ANTICIPATING
THAT THERE WILL BE SOME RESIDUAL BOUNDARIES LEFT OVER IN THE MIX.
A LESS-WORKED OVER SOUTHERN CWA AIR MASS...WITH POSSIBLE LEFT-OVER
WEDNESDAY SMALL SCALE BOUNDARIES (AND MAYBE SOME ASSISTANCE FROM
THE LOCAL BREEZE?) WILL KEEP CHANCE POPS IN PLAY CLOSER TO THE
COAST THURSDAY INTO FRIDAY. A MUCH DRIER AIR MASS FILTERING IN
ALONG THE WESTERN LEG OF A EASTERN-BASED MID-UPPER TROUGH AXIS
WILL COME OVER US DURING THE WEEKEND...SUBSTANTIALLY LOWERING
RAIN CHANCES.
THE EXTENDED SHOWS NOT MUCH IN THE WAY OF ANY DISCERNIBLE WEATHER
FEATURE THAT WILL INCREASE RAIN CHANCES BEYOND THE LOCAL SCALE
BREEZES. IF ANYTHING...RIDGING TAKES MORE OF A GRIP AND MID-LEVELS
ARE MODELED TO WARM BACK UP INTO THE LOWER 20S BY THIS TIME NEXT
WEEK. AS HAS BEEN THE CASE THESE PAST FEW DAYS...THE BAY OF CAMPECHE
HAS REMAINED SOMEWHAT ACTIVE...WITH THE NWP SUITE MAINTAINING
LOWERING PRESSURES AND A GREATER THAN 2 INCH PW AIR MASS. CENTRAL
GULF SHEAR REMAINS STOUT (30 KTS BETWEEN THE TWO UPPER RIDGES) SO
NOT TOO WORRIED WITH ANY CLOSED-OFF CIRCULATION MOVING TOO FAR
NORTH OF THE BAY. 31
&&
.MARINE...
A RELATIVELY FLAT PRESSURE GRADIENT ACROSS THE COASTAL WATERS WILL
KEEP MAINLY LIGHT ONSHORE WINDS AND LOW SEAS IN PLACE THROUGH THE
MIDDLE OF THE WEEK. A WEAK FRONT IS STILL EXPECTED TO APPROACH THE
COAST FROM THE NORTH AND NORTHEAST ON WEDNESDAY NIGHT AND THURSDAY.
THIS BOUNDARY COULD BRING THE AREA A BRIEF PERIOD OF OFFSHORE WINDS.
A WEAK TROUGH OF LOW PRESSURE OVER THE CENTRAL GULF WILL MAINTAIN E-NE
WINDS THROUGH SUNDAY. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 76 94 73 95 75 / 20 60 20 20 10
HOUSTON (IAH) 78 96 76 93 74 / 20 60 30 40 20
GALVESTON (GLS) 83 91 81 90 81 / 10 40 40 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1230 PM CDT TUE AUG 13 2013
.UPDATE...
LATE MORNING SFC ANALYSIS SHOWS A WEAK OUTFLOW BOUNDARY THAT HAD
MOVED TO THE SRN EDGE OF THE FCST AREA EARLIER HAD NOW BEGUN TO
DISSIPATE WITH LIGHT SOUTH WINDS BEGINNING TO OVERTAKE THE SRN
SOUTH PLAINS. MEANWHILE...ANOTHER WEAK BOUNDARY WAS BEGINNING TO
SHARPEN ACROSS THE NRN PANHANDLE...AND IT IS THIS BOUNDARY THAT
THE NAM AND RAP SEEM TO BE KEYING ON FOR AFTN THUNDERSTORM
DEVELOPMENT. 12Z MODEL RUN WANTS TO SHIFT THIS BOUNDARY A BIT
FURTHER SWD THAN PREVIOUS FCST AND AS A RESULT HAVE SHIFTED AXIS
OF HIGHER POPS FOR THE 18Z-00Z TIME FRAME SWD AS WELL. OTHER
CHANGES TO AFTN WERE EVEN MORE MINOR...MAINLY ADJUSTING FOR TRENDS
IN DEW POINT AND WIND.
HAVE LEFT EVENING FCST ALONE FOR NOW. MAY ALSO NEED TO SHIFT
HIGHER POPS SWD THERE...BUT WOULD LIKE TO SEE THE WHITES OF ITS
EYES IN RELATION TO EXPECTED INITIATION ZONE BEFORE MAKING
CHANGES. SECONDARY PRECIP MAY COME WITH HIGH TERRAIN STORMS FROM
NERN NM SURGING SEWD INTO MOIST UPSLOPE FLOW AIDED BY ABOUT 30 KT
FLOW AT 500 MB. ATTM HIGH CHANCE TO LIKELY POPS FAVORING NRN ZONES
STILL APPROPRIATE WITH REEVALUATION FOR THE AFTN PACKAGE.
&&
.AVIATION...
WEAK SFC BOUNDARY SHOULD FOCUS SCATTERED CONVECTION LATE AFTN
EARLY EVENING PROBABLY IN A BAND NEAR BOTH TERMINALS...POSSIBLY
BETWEEN THE TWO...BUT PROBABLY HIGH ENOUGH CONFIDENCE TO INSERT A
TEMPO MENTION. NAM MODEL SEEMS TO BE OVERPLAYING POTENTIAL FOR
MVFR CIGS LATE TONIGHT. THIS IS A BIAS OF THAT MODEL AND FOR NOW
WILL LEAN TOWARD THE MORE OPTIMISTIC GFS.
&&
.PREV DISCUSSION... /ISSUED 639 AM CDT TUE AUG 13 2013/
AVIATION...
A COLD FRONT MOVING THROUGH THE AREA WILL BRING A N-NE WIND SHIFT
TO KLBB BY ABOUT 13Z...FOLLOWED BY PREVAILING E-NE WINDS AT BOTH
TERMINALS THROUGH THE REMAINDER OF THE FCST. SCATTERED SHOWERS AND
THUNDERSTORMS MAY AFFECT EITHER/BOTH TERMINALS THIS AFTERNOON AND
EVENING AND WE HAVE A PROB30 MENTION AT BOTH. THE SHOWER ACTIVITY
MAY CONTINUE OVERNIGHT BUT WITH LOW CONFIDENCE IN THE PARTICULARS.
ALSO...THERE IS SOME INDICATION THAT LOW CEILINGS NEAR OR BELOW
2000 FT MAY DEVELOP AT EITHER TERMINAL...MORE LIKELY AT KCDS. WE
WILL LEAVE MENTION OUT OF TAF FOR NOW UNTIL THERE IS A STRONGER
INDICATION.
PREV DISCUSSION... /ISSUED 419 AM CDT TUE AUG 13 2013/
SHORT TERM...
INITIAL OUTFLOW BOUNDARY MOVED THROUGH MOST OF THE AREA LAST NIGHT
WITH WEAK EASTERLY WINDS NOTED ACROSS ALL BUT THE SW SPLNS...WHERE
WINDS REMAINED SOUTHERLY. WE/VE SEEN SOME MORNING SHOWER ACTIVITY
CROP UP JUST WEST OF THE STATE LINE AS WE CONTINUE TO SEE SOME WEAK
UPPER-AIR RIPPLES ROTATE AROUND A VERY FLAT RIDGE CENTERED OVER SW
TX. FARTHER TO THE NORTH...A W-E BAND OF MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS STRETCHED ACROSS THE NRN TX PANHANDLE WITH A
WELL-DEFINED OUTFLOW/COLD FRONT BOUNDARY MOVING SOUTH...APPROACHING
KAMA AT 3 AM. THIS BOUNDARY SHOULD MOVE INTO OUR NRN ZONES EARLY
THIS MORNING...AND POSSIBLY FARTHER SOUTH BEFORE LOSING MOMENTUM.
SURFACE WINDS WILL BECOME FAIRLY LIGHT ACROSS THE AREA
TODAY...LIKELY WITH A SMALL NORTH TO EAST COMPONENT. THIS SHOULD
MAINTAIN HEALTHY MOISTURE IN PLACE IN THE LOW-LEVELS. ALOFT...WATER
VAPOR IMAGERY THIS MORNING SHOWS A SHORTWAVE LIFTING NORTH ACROSS
THE GREAT BASIN...ANOTHER SWINGING SOUTH THROUGH THE DAKOTAS...WITH
CONVOLUTED FLOW IN-BETWEEN THESE TWO SYSTEMS FROM THE SRN ROCKIES
INTO THE HIGH PLAINS. AN UPPER-LVL JET WILL ADVANCE INTO SRN CO/KS
TODAY...WITH A BELT OF 30+ KT MID-LVL WINDS DEVELOPING ACROSS NE NM
TO WRN OKLA THIS AFTERNOON...AND SPREADING INTO THE NRN SPLNS TO RED
RIVER VALLEY TONIGHT. LIFT WITH THE JET WILL COUPLE WITH LOW-LVL
LIFT IN THE FRONT/OUTFLOW ZONE AND A MODERATELY UNSTABLE AIRMASS TO
SUPPORT CONVECTIVE CHANCES THROUGH THE DAY AND ON INTO THE NIGHT.
HIGH-RES GUIDANCE SUGGESTS THAT THE ACTIVITY IN THE PANHANDLE WILL
SAG SOUTH INTO OUR NRN ZONES THIS MORNING AND WEAKEN. THEN THIS
AFTERNOON...WE SHOULD SEE SCATTERED CONVECTIVE DEVELOPMENT PRIMARILY
ACROSS THE NW PORTIONS OF THE SPLNS AND SWRN TX PANHANDLE...ALTHOUGH
WE CAN/T RULE OUT DEVELOPMENT ALMOST ANYWHERE. STORMS WILL GENERALLY
MOVE EAST AND WILL TAP INTO MLCAPES RUNNING 1000 TO 2000 J/KG AND
0-6 KM BULK SHEAR OF 30 KTS SOUTH TO 40+ KT NORTH. THIS ENVIRONMENT
WILL SUPPORT SOME SEVERE STORM POTENTIAL /MAINLY DAMAGING WIND
GUSTS/ THIS THREAT WILL BE HIGHER ACROSS THE NRN ZONES WHERE THE
SHEAR WILL BE GREATER...BUT WE WILL HAVE TO MONITOR JUST WHERE THE
OUTFLOW BOUNDARY ACTUALLY SETS UP TO ENHANCE LOW-LVL CONVERGENCE AND
LIFT. ALSO...STORM CELLS POSSIBLY TRAINING ON THE COLD SIDE OF THE
BOUNDARY COULD LEAD TO SOME LOCALLY HEAVY RAIN POTENTIAL THIS
EVENING. AS WE HEAD INTO THE OVERNIGHT HOURS...THE FORECAST
CONFIDENCE DECREASES AS BEST UPPER-LEVEL LIFT WILL REMAIN POSITIONED
ACROSS THE NORTH...BUT BEST LOW-LVL FOCUS WILL KEEP SHIFTING
SOUTH...WITH THE FRONT MOVING ON INTO THE PERMIAN BASIN BY EARLY WED
MORNING. THE BULK OF GUIDANCE KEEPS THE HIGHEST RAIN CHANCES PINNED
ACROSS THE NORTH. OVERALL COVERAGE AND STRENGTH OF ACTIVITY IS
EXPECTED TO WANE AFTER MIDNIGHT...ALTHOUGH WE WILL HAVE TO WATCH
BACK TO THE WEST WHERE A OVERNIGHT COMPLEX MAY BEGIN TO FORM NEAR
THE STATE LINE WHERE LIFT FROM NEXT SHORTWAVE STARTS TO IMPINGE ON
POST-FRONTAL UPSLOPE.
LONG TERM...
AN UNSETTLED STRETCH OF WEATHER WILL KICK OFF THE EXTENDED FORECAST
THANKS TO A PERIOD OF NORTHWESTERLY FLOW ALOFT AND A FRONTAL
BOUNDARY IN/NEAR THE AREA. HOWEVER...THE DEVIL IS IN THE DETAILS
WITH MUCH UNCERTAINTY IN THE SPATIAL AND TEMPORAL DISTRIBUTION OF
THE BEST SHOWER/STORM CHANCES RESULTING FROM UNKNOWNS REGARDING
THE EXACT FRONTAL POSITION AND TIMING OF SUBTLE SHORTWAVES MOVING
THROUGH THE FLOW ALOFT.
NORTHWESTERLY MID-LEVEL FLOW WILL BEGIN TO TAKE SHAPE ON WEDNESDAY
AS AN UPPER RIDGE AMPLIFIES OVER THE ROCKIES DOWNSTREAM OF A LARGE
VORTEX CENTERED OFF THE COAST OF BRITISH COLUMBIA. WEST TEXAS WILL
BE POSITIONED BETWEEN THE RIDGE AND LARGE-SCALE TROUGHING ACROSS THE
EASTERN PORTION OF THE CONTINENT. AT THE SFC...A FRONTAL BOUNDARY IS
PROGGED TO SETTLE SOUTHWARD THROUGH MOST IF NOT THE ENTIRE CWA EARLY
WEDNESDAY...WITH RICH POST-FRONTAL MOISTURE ADVECTING IN ON UPSLOPE
WINDS. THIS MOIST ENVIRONMENT WILL READILY SUPPORT PRECIPITATION AND
EFFICIENT RAINFALL RATES GIVEN ANY SUBTLE FORCING FOR ASCENT.
INITIALLY THE FRONTAL FORCING AND PERHAPS WEAK UPPER SUPPORT WILL
KEEP DECENT RAIN CHANCES GOING ON WEDNESDAY...WITH ADDITIONAL
CONVECTION FOCUSED ALONG AND BEHIND THE FRONT AS DAYTIME HEATING
PEAKS AND A POSSIBLE WEAK SHORTWAVE TROUGH APPROACHES. ONE
QUESTION MARK IS HOW MUCH HEATING CAN DEVELOP WEDNESDAY AFTERNOON
WITH THE NAM SUGGESTING LOW CLOUDS MAY HOLD TOUGH MUCH OF THE DAY
AND LIMIT POTENTIAL INSTABILITY. THE ECMWF AND GFS ARE MORE
OPTIMISTIC AND PROJECT SBCAPES CLIMBING TO NEAR OR IN EXCESS OF
1500 J/KG. IF THE STRONGER INSTABILITY IS REALIZED IT COULD BRING
THE POTENTIAL FOR A FEW STRONG TO SEVERE STORMS AS 0-6 KM SHEAR
CLIMBS TO AROUND 35 KNOTS. WE WILL ALSO LOOK FOR THE POSSIBILITY
OF A MCS ROLLING IN LATE FROM THE NORTH...THOUGH THE COOLER AND
MORE STABLE NAM SOLUTION DOES NOT SUPPORT THIS. FOR NOW...HAVE
MADE ONLY MINOR ADJUSTMENTS TO THE POP/WX GRIDS...MAINTAINING A
30-40 PERCENT CHANCE OF STORMS WEDNESDAY AND WEDNESDAY NIGHT. THE
OVERALL SETUP WILL NOT CHANGE MUCH THURSDAY...THOUGH THE FRONTAL
ZONE MAY RETREAT A BIT...SO THUNDER CHANCES WILL CONTINUE WITH NWP
CURRENTLY SUGGESTING ANOTHER SHORTWAVE WILL APPROACH FROM THE
NORTHWEST LATE KEEPING STORM CHANCES GOING LATE INTO THE NIGHT.
THE UPPER FLOW WILL TURN MORE NORTHERLY ON FRIDAY AS THE WESTERN
RIDGE FURTHER AMPLIFIES AND BEGINS TO EDGE EASTWARD. THIS WILL
REDUCE THE CHANCE THAT CONVECTION ORIGINATING OVER THE HIGHER
ELEVATION OF NM AND CO CAN MAKE ITS WAY TO THE SOUTH PLAINS...BUT
WITH THE RESIDUAL FRONTAL BOUNDARY STILL IN THE AREA AND A SHORTWAVE
GRAZING WEST TEXAS FROM THE EAST...HAVE MAINTAINED LOW STORM
CHANCES. DRIER AIR WILL GRADUALLY ADVECT IN ALOFT OVER THE WEEKEND
AS THE UPPER RIDGE BENDS FURTHER EASTWARD AND A DRYING TREND WILL
LIKELY ENSUE. THIS RIDGE WILL GRADUALLY BREAKDOWN LATE WEEKEND INTO
EARLY NEXT WEEK AS A TROUGH EMERGES FROM THE CENTRAL/NORTHERN
ROCKIES. THIS COULD BEND THE MONSOON MOISTURE EASTWARD...PERHAPS
REJUVENATING STORM CHANCES.
REGARDING TEMPERATURES...TENDED TO FAVOR THE COOL SIDE OF GUIDANCE
GIVEN THE EXPECTED CLOUD COVER AND RAIN IN THE AREA MID TO LATE
WEEK. TEMPERATURES WILL GRADUALLY TREND UPWARD BY THIS WEEKEND AS
THE UPPER RIDGE BENDS OVER AND SOUTHERLY LOW-LEVEL FLOW RETURNS TO
WEST TEXAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 85 62 84 61 86 / 40 50 40 40 30
TULIA 86 64 82 63 84 / 40 50 40 40 30
PLAINVIEW 89 65 81 64 84 / 30 40 40 40 30
LEVELLAND 91 66 84 65 88 / 30 30 40 40 30
LUBBOCK 91 68 83 65 86 / 30 30 40 40 30
DENVER CITY 94 66 88 65 91 / 20 20 40 30 30
BROWNFIELD 93 68 86 65 90 / 20 20 40 40 30
CHILDRESS 89 68 85 68 87 / 40 60 40 40 30
SPUR 93 70 86 68 89 / 30 30 40 40 30
ASPERMONT 95 72 89 69 90 / 20 30 40 40 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS SPOKANE WA
245 PM PDT Tue Aug 13 2013
.SYNOPSIS...
A warming and drying trend arrives Wednesday and lingers into
Thursday. A weak cold front will move into the Cascades Thursday
afternoon then trickle across the Inland NW Friday and Saturday.
This will bring a chance for light showers and a few thunderstorms
along with near normal temperatures and locally breezy winds.
Seasonal temperatures and dry conditions will return Sunday into
early next week.
&&
.DISCUSSION...
Tonight: It appears as though there are only a couple of spots of
concern for thunderstorms for the remainder of the afternoon into
the evening. The Blue Mountains, the Camas Prairie and the
mountains of the Idaho Panhandle. Synoptic scale forcing is weak
region wide. As of 2 PM, a small scale vorticity max was moving
out of the southern Idaho Panhandle into western Montana. This
mesoscale feature should enhance the thunderstorm potential in
northwest Montana this evening. The RUC surface CAPE/CIN analysis
suggests that Shoshone, Boundary, Bonner and Pend O`Reille
counties are essentially uncapped with as much as 2000 J/KG of
surface based instability. The HRRR suggests that a few
thunderstorms will develop between 4 PM and 6 PM over central and
southern Shoshone county. It will be interesting to see if
convection will develop in the wake of the departing vorticity
center. Forecasters usually imply that there is subsidence behind
these small vort maxes to suppress convection. I am more confident
that a storm or two will develop over the Blues and over the peaks
near Bonners Ferry. The threat for thunderstorms will decrease
quickly this evening with the loss of surface heating. By 8 PM,
look for clearing skies region-wide.
Wednesday: Hot temperatures will return on Wednesday with low to
mid 90s common over the Inland Northwest. Both the NAM and GFS
forecast a bit of moisture at 700mb Wednesday morning, advancing
northward through the Columbia Basin. This will probably not be
enough moisture to produce high based showers, but we will need to
monitor satellite and radar imagery tonight for the potential of
some light, high based showers in the morning. Otherwise, large
scale subsidence under a building upper ridge axis will cause
temperatures to warm a good 3 to 6 degrees tomorrow over today.
/GKoch
Wednesday night through Saturday: Models are in strong agreement
that the trof of low pressure currently spinning over the Gulf of
AK will eject east and pass through the Inland NW ushering a cool
front across the region. This will bring a chance for showers and
a few thunderstorms along with a cooling trend, and a slight
increase in winds.
The cool front will be reaching the Cascades around mid to late
afternoon on Thursday then slowly trickle across Ern Wa and Nrn
ID during the next 48 hours...barely clearing ID and Ern OR by
Saturday afternoon. This is exceptionally slower then models were
forecasting 24 hours ago but does make sense based on how the
upper-level jet parallels the front. So what does this mean? Well,
there are a few items of interest that could alter the forecast.
All models agree that there will be a rich but narrow fetch of
subtropical moisture absorbed into the system...running
along/ahead of the frontal boundary. So increased clouds are a
definite but given the slow movement of the front and weakening
thermal structure of the front upon crossing into Ern WA...lift
along the frontal boundary will be mediocre. As such,
precipitation along the front will be light and generally in a
slow, top-down saturation regime. This does not mean the region
will escape dry for better chances for precipitation will come in
two other forms.
The first will focus on smaller shortwaves swinging around the parent
low and tracking SW to NE along the baroclinic/frontal zone. GFS
is most robust with these waves but other models do show these
features in one form or another and looking at current water
vapor, the first wave that will swing through on Thursday is
evident via sharp area of darkening near 46N/155W. These are the
waves that tend to bring a quick burst of showers along slow
moving frontal systems that start off looking rather dry as this
did on yesterday`s models. The second feature will be convection
(ie thunderstorms). This pattern does not look overly impressive
or unstable for thunderstorms but it is August and timing will be
key. We did maintain a small threat for thunder over the Cascades
Thursday aftn however clouds should thickening throughout the day
and I am not real confident we can achieve the 500 J/kg of sb CAPE
showing up on the models Thursday aftn in this area. A better
threat for thunderstorms will come across Ern WA and ID Panhandle
Friday afternoon and Saturday as the front trickles this
way/stalls and works in conjunction with peak heating. Model
soundings indicate a modest layer of CIN for most locations away
from the far northern mountains so the lift along the front will
be necessary to lift these parcels and utilize the instability
but given the weakening nature of the front, we kept the main
threat for thunderstorms across the mountains or slightly
downstream of the steering flow.
All things considered, models are generally indicating light pcpn
with this event with the exception of the more robust GFS which
has a few quarter inch bull-eyes...one over the NE Mtns and
second near the Blue Mtns...and for reasoning above...the forecast
may need to trend wetter as these two features become more
apparent. /sb
Saturday Night through Tuesday Night: As the trough that brought
the chance for showers and thunderstorms to much of the region
exits to the east Saturday evening into Sunday we will see slight
chance remain for some showers and isolated t-storms for mainly
the northern ID Panhandle. As this pushes to the east our region
will be left with a general westerly flow. Most of the moisture
with this flow will remain to our north keeping the chance for
precipitation low. Also with the zonal flow we will not see many
changes in our temperatures with most areas sitting in the 80s for
highs and upper 50s to lower 60s for overnight lows. Winds will
die off from the breezy conditions we saw Saturday and look to
remain seasonal for the early part of next week. Models are
hinting at a wave dropping down from the Gulf of Alaska during the
middle part of next week...but with consistency between the
solutions lacking we will hold off on any major changes to the
forecast that far out for now. /Fliehman
&&
.AVIATION...
18Z TAFS: VFR conditions are expected through 14/18z. The only
weather of consequence will be the potential for showers and
isolated thunderstorms over the Idaho panhandle. The thunderstorms
look like they will miss KCOE to the east, but updates will be
likely if the precipitation moves further west. All activity
expected to die off after sunset. ty
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 62 92 66 89 65 85 / 10 10 0 0 10 20
Coeur d`Alene 57 92 60 90 60 85 / 10 10 0 0 10 20
Pullman 51 92 54 90 57 86 / 0 10 0 0 10 20
Lewiston 64 100 66 98 66 94 / 10 0 0 0 0 10
Colville 53 95 57 93 59 87 / 0 10 0 10 20 20
Sandpoint 51 89 53 90 56 87 / 10 10 0 0 10 20
Kellogg 56 91 59 90 57 89 / 20 0 0 0 10 20
Moses Lake 59 95 64 93 65 90 / 10 10 0 10 10 10
Wenatchee 64 93 69 91 67 89 / 10 10 0 10 10 20
Omak 60 95 63 93 63 90 / 0 10 10 10 10 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1216 PM MDT TUE AUG 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENTLY...LOOKING AT MOSAIC RADAR...OUR CWFA IS PRETTY MUCH ECHO
FREE WITH A LINE OF THUNDERSTORMS PUSHING SOUTHEAST IN CENTRAL
NEBRASKA AT 1 AM THIS MORNING. FRONTAL BOUNDARY STILL LAYS UP
ALONG THE LARAMIE RANGE THIS MORNING...EXTENDING NORTHWEST INTO
CENTRAL MONTANA. TO OUR NORTH...A COMPLEX OF THUNDERSTORMS LAYS ACROSS
EASTERN MONTANA JUST EAST OF THE FRONT.
IT REMAINS TO BE SEEN WHAT THAT LINE OF THUNDERSTORMS OVER
NEBRASKA WILL DO TO OUR LOW LEVEL MOISTURE. IT HAS CAUSED WINDS TO
BECOME MORE SOUTHWESTERLY AND THEREFORE A LITTLE DRIER IN THE
PANHANDLE SO FAR. LATEST 11U-3.9U SATELLITE IMAGERY HAS YET TO
SHOW THE ANTICIPATED STRATUS DEVELOPING YET.
THE MORNING SHOULD START OFF DRY WITH INCREASING SHOWERS AND
THUNDERSTORMS DEVELOPING BY NOON. LATEST HRRR COMPOSITE
REFLECTIVITY FORECAST HAS SHOWERS DEVELOPING OVER THE MOUNTAINS TO
THE WEST OF CHEYENNE BY 17Z AND REALLY INCREASING IN COVERAGE
AFTER 19Z. THIS CORRESPONDS WELL WITH THE 00Z ECMWF FORECAST FOR
THE UPPER VORT MAX TO MOVE THROUGH THE UPPER RIDGE THIS AFTERNOON.
FORECAST STORM MOTIONS THIS AFTERNOON ON THE NAM SOUNDINGS SHOW
STORMS TO BE ALMOST STATIONARY. SOME LOCATIONS ARE GOING TO SEE
SOME HEAVY RAINFALL...LIKELY LEADING TO SOME FLASH FLOODING.
CONFIDENCE NO HIGH ON WHERE THESE THUNDERSTORMS ARE GOING TO
DEVELOP...SO WILL HOLD OFF ON ANY WATCHES. BUT DO EXPECT US TO BE
ISSUING FLASH FLOOD WARNINGS FOR SOME AREAS TODAY.
UPPER VORT MAX STAYS WITH US THROUGH THE OVERNIGHT HOURS
TONIGHT...FINALLY EXITING SOUTHEAST WEDNESDAY AFTERNOON. DID KEEP
FAIRLY HIGH POPS GOING TONIGHT THROUGH AT LEAST MIDNIGHT...THEN
PICKING UP AGAIN WEDNESDAY AFTERNOON WITH DAYTIME HEATING.
PATTERN CHANGE THEN BEGINS WEDNESDAY NIGHT INTO THURSDAY AS THE
ECMWF BUILDS THE UPPER LEVEL RIDGE. WITH THE BUILDING RIDGE...THE
DRIER AIR OVER UTAH AND SOUTHERN COLORADO WILL FILTER INTO THE
AREA DURING THE DAY THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 242 AM MDT TUE AUG 13 2013
ALL LONG RANGE MODELS IN AGREEMENT...SHOWING A BREAK IN THE
PERSISTENT MOIST WEATHER PATTERN ACROSS THE FORECAST AREA LATE
THIS WEEK. A DRYING TREND WILL CONTINUE THROUGH SATURDAY WITH
WARMER TEMPERATURES IN THE 80S AND LOW 90S EXPECTED. THE WARMEST
DAY WILL LIKELY BE SATURDAY AS THE RIDGE AXIS SHIFTS EASTWARD INTO
THE PLAINS...WITH HIGHS IN THE MID 80S TO MID 90S
EXPECTED...WARMEST ACROSS THE LOWER ELEVATIONS BELOW 5000 FEET.
KEPT POP BELOW 10 PERCENT WITH LIMITED CLOUD COVER. KEPT
TEMPERATURES A FEW DEGREES BELOW MOS FOR NOW...SINCE IT IS UNCLEAR
HOW THE CURRENT SOIL MOISTURE WILL IMPACT TEMPERATURES AND
HUMIDITY. WITH LIGHT WINDS EXPECTED...DO NOT BELIEVE THE NEAR
SURFACE MOISTURE WILL BE ADVECTED EASTWARD AS THAT QUICK.
PRECIPITATION CHANCES WILL RETURN TO THE AREA BY LATE SUNDAY AND
INTO MONDAY OF NEXT WEEK AS A FAST MOVING PACIFIC TROUGH PUSHES
ACROSS THE NORTHERN AND CENTRAL ROCKIES. SOME COOLER AIR WILL PUSH
INTO THE REGION AS WELL WITH HIGH TEMPERATURES 5 TO 10 DEGREES
COOLER COMPARED TO FRIDAY/SATURDAY. INCREASED POP BETWEEN 20 TO 40
PERCENT FOR SHOWERS AND TSTORMS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1210 PM MDT TUE AUG 13 2013
MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD. SCATTERED SHOWERS
AND TSTMS WILL DEVELOP IN SOUTHEAST WY BY AROUND 20Z AND THEN
SPREAD EASTWARD ACROSS THE PLAINS THROUGH THE EVENING. SOME OF THE
STORMS COULD PRODUCE HEAVIER DOWNPOURS AND BRIEF MVFR VIS. SHOWERS
COULD LINGER OVER THE PANHANDLE THROUGH THE EARLY MORNING ON
WEDNESDAY. WINDS SHOULD GENERALLY REMAIN BELOW 10-15 KTS...HOWEVER
GUSTY WINDS TO 30 KTS COULD OCCUR IN THE VICINITY OF STORMS.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT TUE AUG 13 2013
CURRENT THINKING IS THAT FIRE WEATHER CONCERNS WILL BE MINOR TODAY
AND WEDNESDAY AS MONSOONAL MOISTURE OVER WYOMING WILL CREATE
WIDESPREAD WETTING RAINS FOR MOST LOCATIONS. DRIER AIR BEGINS TO
MOVE INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. AFTERNOON
HUMIDITIES FORECAST TO BE IN THE SINGLE DIGITS ACROSS CARBON
COUNTY THURSDAY AFTERNOON. WINDS ARE EXPECTED TO REMAIN FAIRLY
LIGHT THOUGH AND SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...FINCH
FIRE WEATHER...CLAYCOMB