Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/29/12
AREA FORECAST DISCUSSION
NWS DENVER CO
947 AM MDT FRI JUL 27 2012
.UPDATE...LATEST WATER VAPOR IMAGERY SHOWS MID/UPPER LEVEL
MOISTURE INCREASING ACROSS THE WESTERN TWO THIRDS OF COLORADO
THIS MORNING. INTEGRATED PRECIPIATABLE WATER FROM GPS INDICATES
READINGS WERE ABOUT 0.25 INCH HIGHER THAN YESTERDAY ON THE WEST
SLOPE. THIS MOISTURE WILL SPILL OVER THE TOP OF THE RIDGE TODAY SO
CURRENT FORECAST IS ON TRACK WITH INCREASED STORM COVERAGE THIS
AFTERNOON/EVENING...WITH THE BEST COVERAGE IN THE MOUNTAINS.
LATEST SHORT RANGE MODELS INCLUDING THE HRRR AND RAP SHOW A LITTLE
HIGHER STORM COVERAGE ON THE PLAINS AS WELL. ANY STORMS WILL BE
HIGH BASED SO THREAT OF GUSTY WINDS WITH STORMS IS HIGH ENOUGH TO
WARRANT INCLUSION IN THE LATEST FORECAST.
&&
.AVIATION...STORM COVERAGE IS EXPECTED TO BE A LITTLE HIGHER
TODAY WITH INCREASING MID/HIGH LEVEL MOISTURE. THAT ALONG WITH DRY
SUBCLOUD LAYER SHOULD RESULT IN A RELATIVELY HIGH CHANCE OF GUSTY
OUTFLOW WINDS ASSOCIATED WITH ANY STORMS THAT PUSH OFF THE
FOOTHILLS. WILL GO FOR A PREVAILING STRONGER WESTERLY OUTFLOW WIND
STARTING 20Z-21Z WHICH IS CLOSER TO CLIMATOLOGY IN THESE
SITUATIONS. CHANCE OF STORMS WILL OCCUR FROM 20Z-03Z WITH BEST
CHANCE 21Z-01Z.
&&
.PREV DISCUSSION... /ISSUED 352 AM MDT FRI JUL 27 2012/
SHORT TERM...UPPER LEVEL RIDGE WILL BE CENTERED OVER COLORADO AND
NEW MEXICO TODAY. THIS WILL RESULT IN WEAK FLOW ALOFT OVER THE
STATE. MOISTURE TO INCREASE TODAY...MAINLY OVER THE HIGHER TERRAIN
WHERE PRECIPITABLE WATER VALUES WILL BE A HALF TO THREE QUARTERS OF
AN INCH. JUST A SLIGHT INCREASE ACROSS THE URBAN CORRIDOR AND
EASTERN PLAINS WITH PRECIPITABLE WATER VALUES HOVER JUST BELOW AN
INCH. THIS INCREASE IN MOISTURE AND WEAKENING OF THE MID LEVEL
INVERSION WILL ALLOW SCATTERED THUNDERSTORMS TO FORM OVER THE
FOOTHILLS AND MOUNTAINS. ISOLATED THUNDERSTORMS SHOULD BE ABLE TO
DEVELOP ACROSS THE URBAN CORRIDOR AND NORTHEAST PLAINS. MOISTURE AND
INSTABILITY WILL BE LIMITED...SO THE STORMS ARE EXPECTED TO BE ON
THE WEAK SIDE WITH BRIEF HEAVY RAIN AND WIND GUSTS TO 40 MPH.
CONVECTION WILL COME TO AN END THIS EVENING AS THE AIRMASS
STABILIZES. A SURFACE HIGH OVER THE PLAINS STATES WILL BRING
SOUTHERLY WINDS TODAY WITH GUSTS UP TO 25 MPH TODAY OVER EASTERN
COLORADO.
LONG TERM...THE STRONG UPPER LEVEL SUBTROPICAL HIGH PRESSURE
RIDGE CENTERED OVER THE SOUTHERN GREAT PLAINS WEAKENS SOME AND
SHIFTS WESTWARD ON SATURDAY...THEN BACKS UP OVER TEXAS/OKLAHOMA
AGAIN ON SUNDAY. THIS ALLOWS A MODEST STREAM OF MOIST SUBTROPICAL
AIR TO SURGE NORTHEASTWARD OVER COLORADO ON SUNDAY. 850-500MB
PRECIPITABLE WATER AND MEAN LAYER SPECIFIC HUMIDITY VALUES ON THE
MARGINAL SIDE WHEN IT COME TO HEAVY RAIN PRODUCERS FOR OUR PART OF
THE STATE. BEFORE THIS INFLUX OF MONSOONAL MOISTURE ARRIVES ON
SUNDAY...THERE SHOULD STILL BE ADEQUATE MOISTURE AVAILABLE FOR
ISOLATED SHOWERS IN THE HIGH COUNTRY LATE SATURDAY MORNING AND
SCATTERED T-STORMS IN THE AFTERNOON AND EVENING. ON THE PLAINS
RAIN CHANCES DO NOT LOOK AS PROMISING ALTHOUGH MODELS INDICATE A
LINE OF CONVECTION/QPF ASSOCIATED WITH A BNDRY LAYER SHEAR AXIS/
CONVERGENCE ZONE STRETCHING NORTHEAST FROM SOUTHEAST DOUGLAS
COUNTY DURING THE AFTERNOON AND EARLY EVENING HOURS. THIS COULD
SERVE AS A FOCUS FOR T-STORM DEVELOPMENT DURING THIS PERIOD...BUT
ANY QPF SHOULD REMAIN ON THE LIGHT SIDE...SOMEWHERE IN THE 0.10 TO
0.20 INCH RANGE...ASSUMING STORM UPDRAFTS WILL BE ABLE TO BREAK
THROUGH THE STG MID-LEVEL CAP OVER THE AREA.
ITS SUNDAY WHEN STORM CHANGES SHOULD INCREASE EVERYWHERE WITH
PRECIPITABLE WATER VALUES EAST OF THE MTNS RISING DURING THE
MORNING HOURS WITH EASTERLY UPSLOPE FLOW. BY AFTERNOON UPSLOPE
FLOW APPEARS TO SUBSIDE BUT BY THEN MEAN LAYER PRECIPITABLE WATER
VALUES ARE PROGGED TO BE SOMEWHERE BETWEEN 0.85 AND 1.1 INCH.
THIS LATEST PUSH OF MOIST SUBTROPICAL AIR FROM THE DESERT
SOUTHWEST IS NOT ALL THAT IMPRESSIVE AND THE 850-500MB MEAN LAYER
FLOW MORE WESTERLY THAN SOUTH-SOUTHWESTERLY...CHANCES ARE STORM
MOTIONS WILL BE FASTER AND RAINFALL RATES NOT AS GREAT THIS TIME
AROUND. STILL CAN/T RULE OUT A FEW HEAVY RAIN PRODUCERS MAINLY
OVER THE SOUTHERN FOOTHILLS...PARK COUNTY AND OUT ACROSS THE FAR
NORTHEAST PLAINS LATE IN THE AFTERNOON AND EVENING.
BY MONDAY...THE UPPER RIDGE MAKES A WESTWARD RUN AGAIN ACROSS NEW
MEXICO WHICH PLACES COLORADO UNDER A DRIER...SLIGHTLY WARMER
WESTERLY FLOW. MODELS SHOW PRECIPITABLE WATER VALUES ON THE DOWN
TURN WITH VALUES BY LATE AFTERNOON IN THE 0.65 TO 0.85 INCH RANGE
ON THE PLAINS AND LOWER THAN THAT IN THE HIGH COUNTRY. AIRMASS ON
THE PLAINS...ESPECIALLY NORTH OF INTERSTATE 70 ALSO APPEARS TO BE
QUITE CAPPED WITH WARMING ALOFT WITH THE PASSING RIDGE.
HOWEVER...SHOULD BE ENOUGH MOISTURE AND INSTABILITY AROUND TO
GENERATE SCATTERED LIGHT TO MODERATE T-STORMS IN THE MTNS AND
ISOLATED LATE DAY STORMS ALONG THE PALMER DIVIDE AND OVER THE HIGH
MTN VALLEYS. THE I-25 URBAN CORRIDOR WILL PROBABLY MISS OUT ON ANY
RAIN ON MONDAY.
FOR THE REMAINDER OF THE WEEK...THE UPPER RIDGE IS FORECAST TO
CONTINUE ITS WESTWARD MIGRATION ACCORDING TO THE GFS WITH IT
CENTERED OVER THE 4-CORNERS ON WEDNESDAY AND SLIGHTLY SOUTHWEST OF
THERE ON THURSDAY AND FRIDAY. THE ECMWF DON/T TAKE THE RIDGE AS
FAR WEST BUT IT STILL KEEPS IT OVER NEW MEXICO WHICH ESSENTIALLY
CUTS OFF COLORADO FROM ANY SUBTROPICAL/MONSOONAL MOISTURE FOR
LATER IN THE WEEK. SO EXCEPT FOR THE USUAL ISOLATED AFTERNOON AND
EARLY EVENING GUSTY T-STORMS IN THE HIGH COUNTRY...THE LATTER
HALF OF THE WEEK LOOKS DRY FOR THE PLAINS. TEMPERATURES THROUGHOUT
THE UPCOMING WEEK ARE EXPECTED TO REMAIN ABOVE AVERAGE WITH THE
WARMEST READINGS THIS WEEKEND EVEN WITH THE INCREASE IN STORMS ON
SUNDAY.
AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS.
SCATTERED THUNDERSTORMS WILL FORM OVER THE HIGHER TERRAIN THIS
AFTERNOON. SOME OF THE STORMS WILL SPREAD ONTO THE PLAINS. WIND
GUSTS TO 35 KNOTS AND BRIEF HEAVY RAIN WILL ACCOMPANY THE
THUNDERSTORMS. OUTSIDE OF THE THUNDERSTORMS...SOUTHERLY WINDS
WILL INCREASE THIS AFTERNOON WITH GUSTS UP TO 25 KNOTS.
HYDROLOGY...SCATTERED THUNDERSTORMS WILL DEVELOP OVER THE HIGHER
TERRAIN TODAY. THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING A
BRIEF PERIOD OF HEAVY RAIN. MOISTURE AND INSTABILITY WILL BE
LIMITED SO ANY HEAVY RAIN WILL BE SHORT LIVED. THE THREAT FOR
FLOODING WILL CONTINUE TO BE VERY LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
133 AM EDT FRI JUL 27 2012
.AVIATION...VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD WITH
SEA BREEZES ALONG BOTH COASTS AFT 16Z. THERE COULD BE SOME
CONVECTION INTERIOR BUT IT WILL REMAIN WELL INLAND FROM THE TERMINALS.
KOB
&&
.PREV DISCUSSION... /ISSUED 955 PM EDT THU JUL 26 2012/
UPDATE...A FEW THUNDERSTORMS MANAGED TO DEVELOP OVER THE INTERIOR
DURING THE LATE AFTERNOON AND EVENING HOURS. THE EVENING MIAMI
SOUNDING SHOWS A PWAT OF ONLY 1.40 INCHES WITH VERY DRY AIR ABOVE
6K FT...BUT THERE WAS ENOUGH SEA/LAKE BREEZE CONVERGENCE AND
STRONG HEATING TO GET A FEW TSTORMS GOING. THE TSTORMS HAVE SINCE
DISSIPATED WITH JUST A FEW SHOWERS CONTINUING OVER THE RURAL
INTERIOR. TRANQUIL WEATHER WILL PREVAIL OVERNIGHT. NO SIGNIFICANT
CHANGES ARE NEEDED TO THE FORECAST AT THIS TIME. /GREGORIA
PREV DISCUSSION... /ISSUED 731 PM EDT THU JUL 26 2012/
AVIATION...
THE WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT OVER ALL OF THE
TAF SITES BETWEEN 01Z AND 03Z. THE EAST COAST TAF SITES WINDS WILL
THEN REMAINED LIGHT AND VARIABLE THROUGH 16Z...BEFORE SWINGING TO
A SOUTHEAST DIRECTION AND INCREASING TO AROUND 10 KTS. FOR KAPF
TAF SITE...THE WINDS WILL ALSO REMAIN LIGHT AND VARIABLE FRIDAY
UNTIL 15Z BEFORE SWINGING TO A WESTERLY DIRECTION AT 5 TO 10
KNOTS. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS
AT ALL OF THE TAF SITES TONIGHT THROUGH FRIDAY AFTERNOON.
AVIATION..54/BNB
PREV DISCUSSION... /ISSUED 324 PM EDT THU JUL 26 2012/
UPDATE...A SHOWER HAS RECENTLY DEVELOPED NEAR THE IMMOKALEE
AREA...AND THE CU FIELD IS MORE ESTABLISHED OVER SOUTH FL THIS
AFTERNOON COMPARED TO YESTERDAY. HRRR SHOWS ISOLATED ACTIVITY
DEVELOPING, BECOMING FOCUSED ACROSS THE LAKE OKEECHOBEE REGION.
THERE STILL WILL BE A STRUGGLE TO GET MUCH CONVECTION GOING THIS
AFTERNOON, DUE TO A CAP, BUT STRONG HEATING COULD ALLOW FOR
ISOLATED TSTORMS TO DEVELOP. SO ADDED THIS POSSIBILITY TO THE
FORECAST. /GREGORIA
PREV DISCUSSION... /ISSUED 237 PM EDT THU JUL 26 2012/
DISCUSSION...
THE LATEST GUIDANCE CONTINUES TO INDICATE THE DRIER AND STABLE
AIR MASS CURRENTLY ACROSS THE REGION SHOULD PREVAIL INTO AND
LIKELY THROUGH THE WEEKEND. AN AREA OF HIGH SURFACE PRESSURE JUST
TO THE EAST OF THE BAHAMAS IS FORECAST TO PERSIST INTO AND LIKELY THROUGH
THE WEEKEND. THIS WILL MAINTAIN A WEAKER PRESSURE GRADIENT ACROSS
THE REGION WITH WINDS 10 KNOTS OR LESS ACROSS THE REGIONAL WATERS
WITH THE EAST AND WEST COAST SEA BREEZES EXPECTED EACH DAY FRIDAY
AND THROUGH THE WEEKEND. LOW LEVEL AVAILABLE MOISTURE IS FORECAST
TO BE LIMITED THROUGH THE WEEKEND WITH MINIMAL CHANCE OF
CONVECTION AND PRECIP ACROSS THE REGION AND NONE CURRENTLY IN THE
FORECAST FOR THE NEXT SEVERAL DAYS.
THE LATEST GUIDANCE FOR DUST CONCENTRATIONS INDICATE SAHARAN DUST
CONTINUING ACROSS THE AREA AT LEAST THROUGH FRIDAY WITH HAZY
SKIES EXPECTED AND WILL LIKELY EXTEND INTO THE WEEKEND AS WELL.
MARINE...
A LIGHT SOUTHERLY TO SOUTHEASTERLY FLOW NEAR 10 KNOTS OR LESS
WILL PREVAIL ACROSS REGIONAL WATERS TONIGHT AND IS EXPECTED TO
CONTINUE THROUGH THE WEEKEND WITH MAINLY TRANQUIL SEAS FORECAST
FOR THE LOCAL GULF AND ATLANTIC WATERS TONIGHT THROUGH THE
WEEKEND.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
310 PM EDT FRI JUL 27 2012
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MAIN FORECAST CONCERN IS THUNDERSTORM POTENTIAL THROUGH TOMORROW
ASSOCIATED WITH SEVERAL SHORTWAVES TRAVELING ALONG THE UPPER LEVEL
TROUGH SITUATED ACROSS THE EASTERN CONUS. A VERY MOIST AND UNSTABLE
ATMOSPHERE IS IN PLACE WITH MLCAPE VALUES OF NEAR 3000 J/KG AND PW
VALUES NEAR AND ABOVE 2.0 INCHES. SCATTERED SHOWER AND THUNDERSTORM
DEVELOPMENT HAS BEEN OCCURRING ACROSS THE FORECAST AREA EARLY THIS
AFTERNOON WITH A BIT BETTER ORGANIZED ACTIVITY ACROSS THE SOUTHERN
PORTION THAT INITIATED NEAR AN AREA OF ENHANCED BAROCLINICITY DUE TO
SOLAR SHELTERING FROM REMNANT CLOUD COVERAGE THIS MORNING. AMONG THE
ENSEMBLE OF AVAILABLE HI-RES GUIDANCE SOLUTIONS...THE HRRR SO FAR
HAS BEEN VERIFYING WELL WITH THE EARLY CONVECTIVE DEVELOPMENT AND IS
STARTING TO PICK UP MORE ON THE INFLUENCE OF THE SHORTWAVE IN THE
NORTHERN PORTION CLOSER TO 00Z THIS EVENING. THE WRF IS A BIT MORE
ROBUST WITH THIS LATER DEVELOPMENT. WILL THEREFORE EXPECT SEVERAL
ROUNDS OF DEVELOPMENT FROM THIS AFTERNOON THROUGH TONIGHT WITH THE
MORE ORGANIZED DEVELOPMENT AND GREATER SEVERE POTENTIAL OCCURRING
FROM ABOUT 23-02Z ACROSS THE NORTH. SPC ALSO HAS THIS AREA INCLUDED
IN A SLIGHT RISK. THE MAIN THREATS WILL BE STRONG WINDS AND HEAVY
RAINFALL WITH DOWNDRAFT CAPE ALREADY NEAR 1000 J/KG ACROSS THE NORTH
AND MUCH HYDROMETEOR LOADING EXPECTED WITH SUCH A MOIST THERMAL
PROFILE. FREQUENT LIGHTNING AND SMALL HAIL WILL ALSO BE POSSIBLE.
ISOLATED SEVERE STORM POTENTIAL IS ACROSS THE SOUTH AS WELL AS THE
MORE ENHANCED MOISTURE FIELD RESIDES NEAR A PERSISTENT SFC TROUGH.
HAVE GONE WITH LIKELY POPS IN THE NORTH AND SOUTH FROM 21-00Z
TRENDING INTO CHANCE POPS TONIGHT AND DECREASING TO SLIGHT ACROSS
THE NORTH NEAR EARLY MORNING.
MAINTAINING CHANCE POPS ACROSS SOUTHERN PORTION OVERNIGHT AND
EXPANDING BACK ACROSS MAJORITY OF AREA ON SATURDAY AS THE NAM
SUGGESTS ANOTHER SHORTWAVE RIPPLING ALONG UPPER TROUGH. GUIDANCE IS
IN GENERAL AGREEMENT WITH THE MAIN TROUGH AXIS LINGERING NEAR THE
EASTERN PORTION OF THE AREA INTO SUNDAY. PORTIONS OF THE SOUTH AND
EAST WILL THEREFORE HAVE SLIGHT TO CHANCE POPS OVERNIGHT SATURDAY.
FOR TEMPS...BLEND OF MAV AND MET LOOKS REASONABLE WITH GENERALLY
LOWER TEMPS THAN PREVIOUS DAYS AND INCREASED CLOUD COVERAGE
EXPECTED. ATTM THE PROGGED TEMPS AND DEWPOINTS DO NOT MEET HEAT
ADVISORY CRITERIA FOR SATURDAY... SO AM CURRENTLY PLANNING ON NO
ADDITIONAL ISSUANCE.
BAKER
.LONG TERM /SUNDAY THROUGH FRIDAY/...
NOT MUCH CHANGE TO THE PREVIOUS GRIDS. DID INCREASE POPS ON SUNDAY
IN RESPONSE TO THE WEAK STATIONARY FRONT AND PROXIMITY OF THE
TROUGH AXIS...PROGGED TO BE PRETTY MUCH PARKED OVER THE
APPALACHIANS DURING THE DAY ON SUNDAY...WITH A SHORTWAVE PUSHING
INTO THE AREA. BEST CHANCES WILL BE IN THE SOUTHEAST HALF TO 2/3
OF THE FORECAST AREA...BUT CANNOT RULE OUT TOPOGRAPHICALLY-INDUCED
CONVECTION IN THE NORTHEAST MOUNTAINS. THE NAM GOES A LITTLE NUTS
WITH CONVECTION AS THE RESULT OF A VORT LOBE RIDING DOWN THE FLOW
ALOFT. ECMWF DOES ACTUALLY HAVE SOMETHING SIMILAR BUT WITH LESS
CONVECTIVE FEEDBACK AND THUS A MORE REASONABLE QPF FIELD.
OTHERWISE...ONLY MINOR CHANGES MADE TO THE EXTENDED PARTIALLY TO
ACCOUNT FOR NEW GUIDANCE MODERATING THE TEMPS SOMEWHAT MONDAY INTO
TUESDAY. SEE PREVIOUS DISCUSSION BELOW.
TDP
PREV DISCUSSION... /ISSUED 346 AM EDT FRI JUL 27 2012/
A COLD FRONT OVER THE CENTRAL GA AREA EARLY SUNDAY WILL LIKELY
BECOME STATIONARY...DISSIPATING INTO TUESDAY. DURING THIS TIME AN
UPPER TROUGH SETS UP OVER THE EASTERN STATES WITH NW FLOW
AFFECTING THE AREA AND THE POTENTIAL FOR SHORT WAVES IN THAT FLOW
TO BRING SOME AMOUNT OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THIS PATTERN LOOKS TO CONTINUE THROUGH THE REST OF THE LONG TERM
WITH INDICATIONS OF ANOTHER FRONT MOVING TO THE AREA ON THURSDAY.
AS THE UPPER TROUGH BECOMES BETTER ESTABLISHED AND DEEPENS OVER THE
AREA DURING MID WEEK OR SO...THIS SHOULD COOL HIGH TEMPERATURES
CLOSER TO NORMAL.
&&
.AVIATION...
18Z UPDATE...
MOSTLY VFR CONDITIONS EXPECTED AND REDUCED VSBYS POSSIBLE WITH ANY
CONVECTION. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN
DEVELOPING THIS AFTERNOON AND SHOULD CONTINUE INTO THIS EVENING
WITH ANOTHER MORE WIDESPREAD ROUND POSSIBLE CLOSER TO 00Z FOR THE
NORTHERN SITES. CURRENTLY INCLUDING TEMPO GROUP FOR -TSRA FROM
19-23Z TODAY WITH THE POTENTIAL FOR EXTENDING IT TO ABOUT 02Z
LATER ON. CIGS HAVE RAISED TO NEAR BKN040. THERE IS THE POTENTIAL
FOR MVFR CIGS NEAR 13Z TOMORROW WITH SOME LOW LEVEL MOISTURE...BUT
WILL GO FEW030 BECOMING SCT040 BY 15Z FOR NOW. WINDS MOSTLY WEST
BECOMING WNW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE IN DURATION OF CONVECTION TODAY AND CIGS OVERNIGHT.
HIGH CONFIDENCE ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 73 95 72 94 / 30 40 20 20
ATLANTA 74 93 75 92 / 30 40 10 20
BLAIRSVILLE 66 89 66 88 / 40 30 10 20
CARTERSVILLE 71 93 70 92 / 40 30 10 10
COLUMBUS 76 94 76 93 / 30 40 20 30
GAINESVILLE 72 91 73 93 / 30 30 20 20
MACON 74 94 74 94 / 30 40 20 30
ROME 71 94 70 93 / 30 30 10 10
PEACHTREE CITY 72 93 70 91 / 30 40 20 20
VIDALIA 76 95 76 94 / 30 40 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BLECKLEY...CRISP...DODGE...DOOLY...EMANUEL...HOUSTON...
JEFFERSON...JOHNSON...LAURENS...MONTGOMERY...PULASKI...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.
&&
$$
SHORT TERM...BAKER
LONG TERM....TDP
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
204 PM EDT FRI JUL 27 2012
.PREV DISCUSSION... /ISSUED 1105 AM EDT FRI JUL 27 2012/
.UPDATE...
SHOWER AND ISOLATED THUNDERSTORM ACTIVITY HAS PERSISTED THIS MORNING
IN PARTS OF THE SOUTH. ANY LINGERING BOUNDARIES OR ENHANCED
BAROCLINITY DUE TO SOLAR SHELTERING FROM REMNANT CLOUD COVERAGE MAY
FOCUS SOME EARLIER REDEVELOPMENT THIS AFTERNOON. WHEN CONSIDERING
THE LATEST HI-RES SHORT TERM GUIDANCE... THE HRRR SOLUTION HAS A
BETTER HOLD ON SOME OF THE LINGERING CONVECTION IN THE SOUTH THIS
MORNING AND SUGGESTS SCATTERED REDEVELOPMENT ACROSS MUCH OF CENTRAL
AND NORTHERN GA AS EARLY AS 17Z. LATELY THE HRRR SEEMS TO BE A BIT
BULLISH WITH DEVELOPMENT EARLY ON. IT ALSO DOES NOT HAVE NEARLY AS
MUCH CONVECTION TRIGGER FROM THE IMPINGING UPPER SHORTWAVE TROUGH
FROM THE NORTH LATER...WHICH THE WRF BUYS INTO MORE. STILL THINKING
THE NORTH WILL HAVE BETTER CHANCES LATER DUE TO APPROACH OF UPPER
TROUGH...AND PARTS OF THE SOUTH WILL HAVE DECENT CHANCES AS WELL
WITH ENHANCED MOISTURE FIELD AND AFOREMENTIONED REMNANT MORNING
ACTIVITY. WILL MAINTAIN CHANCE POPS EARLY AREA-WIDE TRENDING TO
LIKELY POPS IN THE NORTH AND SOUTH FROM 21-00Z.
OTHERWISE...BUMPED DOWN TEMPS IN THE SOUTH DUE TO LINGERING
PRECIP/CLOUD COVERAGE AND MADE ADJUSTMENTS TO DEWPOINT TRENDS.
CHANGES STILL KEPT MUCH OF THE SOUTHERN PORTION WITHIN A FEW DEGREES
OF HEAT ADVISORY CRITERIA SO WILL MAINTAIN CURRENT PRODUCT. PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 346 AM EDT FRI JUL 27 2012/
HEAT ADVISORY FOR SOUTHEAST SECTIONS THIS AFTERNOON...
.SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST SHOWS TROUGH REMAINS IN
PLACE ALONG THE EASTERN SEABOARD INTO THE CAROLINAS WITH SOME WEAK
RIDGING NOTED OVER WESTERN GEORGIA. ENHANCED CLUSTER OF STORMS
WHICH DEVELOPED OVER SOUTHERN SECTIONS LAST EVENING AND SENT
DEVELOPING OUTFLOWS NORTHWARD HAS LONG SINCE ABATED LEAVING BEHIND
MOSTLY CLOUDY CONDITIONS. MOST ALL OF THIS IS IN THE FORM OF HIGH
CLOUDS WITH NO LOW CLOUDS OF NOTE TO THE WEST EVEN THOUGH MODELS
ARE BULLISH ON THE FORMATION LATER TONIGHT INTO FRIDAY MORNING.
WITH YESTERDAYS ACTIVITY...ESPECIALLY LATE STORMS OVER THE
NORTH...ATMOSPHERE IS SLOWLY PROVING IT CAN SUSTAIN CONVECTION
WITH DECAYING RIDGE. TODAY LOOKS TO BE A TRANSITION DAY FOR THE
AREA AS TROUGH BECOMES MORE ENTRENCHED INTO THE TENNESSEE VALLEY
ALLOWING FOR FURTHER BREAKDOWN OF THE RIDGE. BASED ON MOISTURE
DISTRIBUTION...WITH ENHANCED LOW LEVEL MOISTURE FROM COLUMBUS TO
MACON...FEEL THESE AREAS WILL SEE INITIATION FIRST WITH AREAS TO
THE NORTH RECEIVING A LATER START AS SHORTWAVE ENERGY APPROACHES.
CAPE VALUES AREA WIDE LOOK TO BE IN THE 3000 PLUS RANGE THIS
AFTERNOON AND WITH BETTER SYNOPTIC SETUP...HAVE GONE 10 TO 30
PERCENT ABOVE GUIDANCE FOR MOST AREAS.
ALTHOUGH TIMING OF STORMS WILL BE KEY...STILL LOOKING AT SOUTHEAST
SECTIONS POSSIBLE SEEING HEAT INDICES IN EXCESS OF 105 THIS
AFTERNOON AND HEAT ADVISORY WILL BE POSTED.
AS FAR AS SEVERE POTENTIAL TODAY...ISOLATED SEVERE STORMS WILL BE
POSSIBLE AREA WIDE BUT APPEARS BEST CHANCE FOR ORGANIZED SEVERE
WILL BE TO THE NORTH WITH APPROACHING UPPER LEVEL ENERGY.
DOWNDRAFT CAPE NOT ALL THAT IMPRESSIVE TODAY WITH VALUES LESS THAN
500 J/KG FOR THE MOST PART BUT PRECIPITATION LOADING ALONE WILL
STILL LEAD TO ISOLATED STRONG TO SEVERE STORMS. TEMPS ALOFT WILL
NOT BE ESPECIALLY COLD EITHER WITH 500 TEMPS AROUND -6C TO -7C BUT
AGAIN...SOME ISOLATED SEVERE HAIL POSSIBLE AS WAS THE CASE LAST
NIGHT.
FOR SATURDAY...MODELS ALL WANT TO PUSH FRONTAL BOUNDARY INTO
SOUTHERN SECTIONS OF THE FORECAST AREA AND KEEP NORTHERN SECTIONS
DRY. STRONG SHORTWAVE ARRIVES LATE IN THE DAY HOWEVER FOR THE
NORTH AND FEEL ENOUGH MOISTURE WILL BE PRESENT ALONG WITH
CONTINUED HIGH INSTABILITY TO WARRANT LOW END CHANCE POPS FROM
ATLANTA NORTHWARD. CONTINUED STEAMY TO THE SOUTH IN VICINITY OF
THE FRONT AND DEPENDING ON HOW TODAY FARES...MAY NEED ANOTHER HEAT
ADVISORY FOR SATURDAY AS WELL.
DEESE
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT OVER THE CENTRAL GA AREA EARLY SUNDAY WILL LIKELY
BECOME STATIONARY...DISSIPATING INTO TUESDAY. DURING THIS TIME AN
UPPER TROUGH SETS UP OVER THE EASTERN STATES WITH NW FLOW
AFFECTING THE AREA AND THE POTENTIAL FOR SHORT WAVES IN THAT FLOW
TO BRING SOME AMOUNT OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THIS PATTERN LOOKS TO CONTINUE THROUGH THE REST OF THE LONG TERM
WITH INDICATIONS OF ANOTHER FRONT MOVING TO THE AREA ON THURSDAY.
AS THE UPPER TROUGH BECOMES BETTER ESTABLISHED AND DEEPENS OVER THE
AREA DURING MID WEEK OR SO...THIS SHOULD COOL HIGH TEMPERATURES
CLOSER TO NORMAL.
BDL
&&
.AVIATION...
18Z UPDATE...
MOSTLY VFR CONDITIONS EXPECTED AND REDUCED VSBYS POSSIBLE WITH ANY
CONVECTION. SCATTERED SHOWER AND ISOLATED THUNDERSTORMS HAVE BEEN
DEVELOPING THIS AFTERNOON AND SHOULD CONTINUE INTO THIS EVENING
WITH ANOTHER MORE WIDESPREAD ROUND POSSIBLE CLOSER TO 00Z FOR THE
NORTHERN SITES. CURRENTLY INCLUDING TEMPO GROUP FOR -TSRA FROM
19-23Z TODAY WITH THE POTENTIAL FOR EXTENDING IT TO ABOUT 02Z
LATER ON. CIGS HAVE RAISED TO NEAR BKN040. THERE IS THE POTENTIAL
FOR MVFR CIGS NEAR 13Z TOMORROW WITH SOME LOW LEVEL MOISTURE...BUT
WILL GO FEW030 BECOMING SCT040 BY 15Z FOR NOW. WINDS MOSTLY WEST
BECOMING WNW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE IN DURATION OF CONVECTION TODAY AND CIGS OVERNIGHT.
HIGH CONFIDENCE ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 94 73 94 72 / 40 30 30 20
ATLANTA 93 74 92 74 / 50 30 30 10
BLAIRSVILLE 90 66 88 67 / 60 40 30 10
CARTERSVILLE 92 72 93 68 / 60 40 30 10
COLUMBUS 95 75 94 76 / 60 30 30 20
GAINESVILLE 92 73 91 72 / 50 30 30 20
MACON 94 74 95 73 / 60 30 30 20
ROME 93 71 95 68 / 60 30 30 10
PEACHTREE CITY 93 71 92 70 / 50 30 30 20
VIDALIA 94 76 94 75 / 40 30 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BLECKLEY...CRISP...DODGE...DOOLY...EMANUEL...HOUSTON...
JEFFERSON...JOHNSON...LAURENS...MONTGOMERY...PULASKI...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.
&&
$$
SHORT TERM...DEESE/BAKER
LONG TERM....BDL
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1105 AM EDT FRI JUL 27 2012
.UPDATE...
SHOWER AND ISOLATED THUNDERSTORM ACTIVITY HAS PERSISTED THIS MORNING
IN PARTS OF THE SOUTH. ANY LINGERING BOUNDARIES OR ENHANCED
BAROCLINITY DUE TO SOLAR SHELTERING FROM REMNANT CLOUD COVERAGE MAY
FOCUS SOME EARLIER REDEVELOPMENT THIS AFTERNOON. WHEN CONSIDERING
THE LATEST HI-RES SHORT TERM GUIDANCE... THE HRRR SOLUTION HAS A
BETTER HOLD ON SOME OF THE LINGERING CONVECTION IN THE SOUTH THIS
MORNING AND SUGGESTS SCATTERED REDEVELOPMENT ACROSS MUCH OF CENTRAL
AND NORTHERN GA AS EARLY AS 17Z. LATELY THE HRRR SEEMS TO BE A BIT
BULLISH WITH DEVELOPMENT EARLY ON. IT ALSO DOES NOT HAVE NEARLY AS
MUCH CONVECTION TRIGGER FROM THE IMPINGING UPPER SHORTWAVE TROUGH
FROM THE NORTH LATER...WHICH THE WRF BUYS INTO MORE. STILL THINKING
THE NORTH WILL HAVE BETTER CHANCES LATER DUE TO APPROACH OF UPPER
TROUGH...AND PARTS OF THE SOUTH WILL HAVE DECENT CHANCES AS WELL
WITH ENHANCED MOISTURE FIELD AND AFOREMENTIONED REMNANT MORNING
ACTIVITY. WILL MAINTAIN CHANCE POPS EARLY AREA-WIDE TRENDING TO
LIKELY POPS IN THE NORTH AND SOUTH FROM 21-00Z.
OTHERWISE...BUMPED DOWN TEMPS IN THE SOUTH DUE TO LINGERING
PRECIP/CLOUD COVERAGE AND MADE ADJUSTMENTS TO DEWPOINT TRENDS.
CHANGES STILL KEPT MUCH OF THE SOUTHERN PORTION WITHIN A FEW DEGREES
OF HEAT ADVISORY CRITERIA SO WILL MAINTAIN CURRENT PRODUCT. PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 346 AM EDT FRI JUL 27 2012/
.HEAT ADVISORY FOR SOUTHEAST SECTIONS THIS AFTERNOON...
.SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST SHOWS TROUGH REMAINS IN
PLACE ALONG THE EASTERN SEABOARD INTO THE CAROLINAS WITH SOME WEAK
RIDGING NOTED OVER WESTERN GEORGIA. ENHANCED CLUSTER OF STORMS
WHICH DEVELOPED OVER SOUTHERN SECTIONS LAST EVENING AND SENT
DEVELOPING OUTFLOWS NORTHWARD HAS LONG SINCE ABATED LEAVING BEHIND
MOSTLY CLOUDY CONDITIONS. MOST ALL OF THIS IS IN THE FORM OF HIGH
CLOUDS WITH NO LOW CLOUDS OF NOTE TO THE WEST EVEN THOUGH MODELS
ARE BULLISH ON THE FORMATION LATER TONIGHT INTO FRIDAY MORNING.
WITH YESTERDAYS ACTIVITY...ESPECIALLY LATE STORMS OVER THE
NORTH...ATMOSPHERE IS SLOWLY PROVING IT CAN SUSTAIN CONVECTION
WITH DECAYING RIDGE. TODAY LOOKS TO BE A TRANSITION DAY FOR THE
AREA AS TROUGH BECOMES MORE ENTRENCHED INTO THE TENNESSEE VALLEY
ALLOWING FOR FURTHER BREAKDOWN OF THE RIDGE. BASED ON MOISTURE
DISTRIBUTION...WITH ENHANCED LOW LEVEL MOISTURE FROM COLUMBUS TO
MACON...FEEL THESE AREAS WILL SEE INITIATION FIRST WITH AREAS TO
THE NORTH RECEIVING A LATER START AS SHORTWAVE ENERGY APPROACHES.
CAPE VALUES AREA WIDE LOOK TO BE IN THE 3000 PLUS RANGE THIS
AFTERNOON AND WITH BETTER SYNOPTIC SETUP...HAVE GONE 10 TO 30
PERCENT ABOVE GUIDANCE FOR MOST AREAS.
ALTHOUGH TIMING OF STORMS WILL BE KEY...STILL LOOKING AT SOUTHEAST
SECTIONS POSSIBLE SEEING HEAT INDICES IN EXCESS OF 105 THIS
AFTERNOON AND HEAT ADVISORY WILL BE POSTED.
AS FAR AS SEVERE POTENTIAL TODAY...ISOLATED SEVERE STORMS WILL BE
POSSIBLE AREA WIDE BUT APPEARS BEST CHANCE FOR ORGANIZED SEVERE
WILL BE TO THE NORTH WITH APPROACHING UPPER LEVEL ENERGY.
DOWNDRAFT CAPE NOT ALL THAT IMPRESSIVE TODAY WITH VALUES LESS THAN
500 J/KG FOR THE MOST PART BUT PRECIPITATION LOADING ALONE WILL
STILL LEAD TO ISOLATED STRONG TO SEVERE STORMS. TEMPS ALOFT WILL
NOT BE ESPECIALLY COLD EITHER WITH 500 TEMPS AROUND -6C TO -7C BUT
AGAIN...SOME ISOLATED SEVERE HAIL POSSIBLE AS WAS THE CASE LAST
NIGHT.
FOR SATURDAY...MODELS ALL WANT TO PUSH FRONTAL BOUNDARY INTO
SOUTHERN SECTIONS OF THE FORECAST AREA AND KEEP NORTHERN SECTIONS
DRY. STRONG SHORTWAVE ARRIVES LATE IN THE DAY HOWEVER FOR THE
NORTH AND FEEL ENOUGH MOISTURE WILL BE PRESENT ALONG WITH
CONTINUED HIGH INSTABILITY TO WARRANT LOW END CHANCE POPS FROM
ATLANTA NORTHWARD. CONTINUED STEAMY TO THE SOUTH IN VICINITY OF
THE FRONT AND DEPENDING ON HOW TODAY FARES...MAY NEED ANOTHER HEAT
ADVISORY FOR SATURDAY AS WELL.
DEESE
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT OVER THE CENTRAL GA AREA EARLY SUNDAY WILL LIKELY
BECOME STATIONARY...DISSIPATING INTO TUESDAY. DURING THIS TIME AN
UPPER TROUGH SETS UP OVER THE EASTERN STATES WITH NW FLOW
AFFECTING THE AREA AND THE POTENTIAL FOR SHORT WAVES IN THAT FLOW
TO BRING SOME AMOUNT OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THIS PATTERN LOOKS TO CONTINUE THROUGH THE REST OF THE LONG TERM
WITH INDICATIONS OF ANOTHER FRONT MOVING TO THE AREA ON THURSDAY.
AS THE UPPER TROUGH BECOMES BETTER ESTABLISHED AND DEEPENS OVER THE
AREA DURING MID WEEK OR SO...THIS SHOULD COOL HIGH TEMPERATURES
CLOSER TO NORMAL.
BDL
&&
.AVIATION...
12Z UPDATE...
EARLY START TO TSRA FOR SOUTHERN SECTIONS THIS MORNING BUT THUS
FAR HAS REMAINED NORTH OF MCN AND CSG. LOOKING FOR ENHANCED LOW
LEVEL MOISTURE TO PUSH IN FROM THE SOUTH AND WEST THIS MORNING BUT
MUCH UNCERTAINTY HOW SOON AND FAR EAST AND NORTH THIS WILL
PROGRESS. WILL HAVE SLIGHTLY EARLIER START FOR THE SOUTHERN TAF
SITES BUT THINKING A MAJORITY OF THE ACTIVITY WILL BE LATE AND
ASSOCIATED WITH AN UPPER LEVEL SYSTEM MOVING OUT OF TENNESSEE.
HAVE GONE WITH PROB30 AFT 22Z BUT THIS ORGANIZED LINE OF STORMS
COULD ACTUALLY MATERIALIZE A FEW HOURS AFTER THIS ADVERTISED TIME
GIVEN UNCERTAINTY.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON TSRA CHANCES AND TIMING.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 94 73 94 72 / 40 30 30 20
ATLANTA 93 74 92 74 / 50 30 30 10
BLAIRSVILLE 90 66 88 67 / 60 40 30 10
CARTERSVILLE 92 72 93 68 / 60 40 30 10
COLUMBUS 95 75 94 76 / 60 30 30 20
GAINESVILLE 92 73 91 72 / 50 30 30 20
MACON 94 74 95 73 / 60 30 30 20
ROME 93 71 95 68 / 60 30 30 10
PEACHTREE CITY 93 71 92 70 / 50 30 30 20
VIDALIA 94 76 94 75 / 40 30 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BLECKLEY...CRISP...DODGE...DOOLY...EMANUEL...HOUSTON...
JEFFERSON...JOHNSON...LAURENS...MONTGOMERY...PULASKI...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.
&&
$$
SHORT TERM...DEESE/BAKER
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 PM CDT FRI JUL 27 2012
.SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB LOW NEAR KGRB WITH AN OCCLUDED FRONT
RUNNING INTO SOUTHWEST LOWER MICHIGAN. THE 850MB COLD FRONT RAN
FROM SOUTHWEST LOWER MICHIGAN INTO SOUTHERN NEBRASKA. SATELLITE
AND RADAR TRENDS THROUGH MID AFTERNOON SHOW PLENTY OF DIURNAL CU
WITH SHRA/TSRA ACROSS WISCONSIN.
18Z SFC ANALYSIS HAS A LOW NEAR KMKG WITH A COLD FRONT RUNNING
SOUTHWEST TO THE KSTL AREA AND THEN INTO NORTHEAST OKLAHOMA.
SEVERAL TROFS WERE BEHIND THE COLD FRONT FROM CENTRAL ILLINOIS
BACK NORTH INTO CENTRAL WISCONSIN. DEW POINTS WERE IN THE 50S AND
60S BEHIND THE FRONT WITH 60S AND 70S ACROSS THE OHIO VALLEY AND
DEEP SOUTH.
&&
.SHORT TERM...TONIGHT AND SATURDAY
THE FIRST QUESTION IS WILL DIURNAL CONVECTION DEVELOP LATE THIS
AFTERNOON. THE 20Z OBS INDICATE THE NORTHEAST CWFA IS WITHIN A FEW
DEGREES OF CONVECTIVE TEMPERATURE. IF CONVECTIVE TEMPERATURE CAN
BE REACHED BY 22Z AND A PARCEL CAN BE LIFTED TO THE LFC...
CONVECTION SHOULD ENSUE THAT DISSIPATES WITH SUNSET. RAP TRENDS
SHOW A WEAK THETA E GRADIENT DEVELOPING FROM ABOUT KPDC TO KSQI
WITH SOME FORCING ALONG IT. RADAR ALSO SHOWS SOME VERY WEAK
RETURNS BETWEEN KEFT AND KOVS IN SOUTHERN WISCONSIN.
SO...ALTHOUGH THE CHANCES ARE NOT GREAT...PROBABLY 1 IN 3... WILL
ADD A MENTION OF ISOLATED SHRA/TSRA VERY LATE THIS AFTERNOON UP TO
SUNSET. AT BEST THERE MAY ONLY BE A HANDFUL OF CELLS THAT DEVELOP.
IF NO CONVECTION DEVELOPS BY 2230Z...THE LATE AFTERNOON AND
EVENING IN THE NORTHEAST CWFA WILL LIKELY REMAIN DRY.
AS HIGH PRESSURE BUILDS INTO THE AREA LATE TONIGHT WINDS WILL
DIMINISH. AS TEMPERATURES DROP THE QUESTION THEN TURNS TO FOG
POTENTIAL. WHAT LITTLE RAIN THAT HAS OCCURRED RECENTLY HAS DONE
LITTLE TO MOISTEN THE GROUND. HOWEVER...A READY SOURCE OF MOISTURE
IS THE RIVERS. AN APPROACHING VORT MAX FROM THE PLAINS MAY ALLOW
SOME HIGH LEVEL CLOUDS TO SPILL INTO THE AREA PRIOR TO DAWN AND ANY
FOG DEVELOPMENT WILL BE VERY PATCHY. THUS WILL MENTION SOME PATCHY
RIVER VALLEY FOG IN THE NORTHERN CWFA LATE TONIGHT AND EARLY
SATURDAY MORNING.
MCS AND LIFT TOOLS ALL INDICATE A RESPECTABLE MCS SHOULD FIRE
TONIGHT IN THE PLAINS AND HEAD EAST. CLOUDS FROM THIS MCS SHOULD
SLOWLY OVERTAKE THE CWFA SATURDAY MORNING.
SATURDAY AFTERNOON...THE BETTER MOISTURE AND SUPPORT REMAIN WEST
OF THE CWFA PER THE MCS AND LIFT TOOLS. HOWEVER...DIURNAL HEATING
ON ANY OUTFLOW BOUNDARY FROM THE NOCTURNAL MCS SHOULD HELP
INITIATE CONVECTION IN CENTRAL IOWA THAT SLOWLY MOVES EAST. SO...
SCHC POPS FOR ISOLATED CONVECTION WILL BE ADDED TO THE FAR WESTERN
CWFA LATE SATURDAY AFTERNOON. TEMPERATURES ON SATURDAY SHOULD
AGAIN BE CLOSE TO NORMAL. ..08..
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY
SATURDAY NIGHT WILL BE VERY INTERESTING. SEVERAL MODELS HAVE
INDICATIONS THAT AN MCS WILL FORM IN NORTH CENTRAL OR NORTHWEST
IOWA...ALONG AN INSTABILITY GRADIENT AND 850MB BAROCLINIC ZONE. THE
MODELS HAVE A LOT OF DIFFERENCES IN WHERE THE SURFACE FEATURES AND
QPF ARE FOR THIS EVENT...BUT THE MID LEVEL BAROCLINIC ZONE IS FAIRLY
SIMILAR...WHICH FAVORS THE NORTHWEST OR NORTH CENTRAL IOWA LOCATION.
THIS POTENTIAL AREA OF CONVECTION WOULD SLIDE SOUTHEAST SATURDAY
NIGHT...AND AFFECT MAINLY THE WESTERN HALF OF THE FORECAST AREA LATE
SATURDAY NIGHT AND SUNDAY. HAVE RAISED POPS FOR THIS AREA...BUT
HAVE STILL LEFT IN THE CHANCE CATEGORY AND WILL LET LATER SHIFTS
RE-EVALUATE. HAVE ALSO KEPT HIGH TEMPERATURES IN THE 80S TO NEAR 90
SUNDAY...KNOWING THAT IF THIS EVENT IS MORE WIDESPREAD THAN
ANTICIPATED...THIS FORECAST WILL BE TOO WARM.
SUNDAY NIGHT MODELS TRY TO START ANOTHER MCS SOMEWHERE IN THE
GENERAL VICINITY...BUT MCS TECHNIQUES ARE LESS FAVORABLE AND WOULD
INDICATE A LOCATION FARTHER EAST OR SOUTH. SO...HAVE KEPT POPS IN
THE SLIGHT OR LOW END CHANCE POP RANGE FOR SUNDAY NIGHT AND MONDAY FOR
NOW...AND WILL LET LATER SHIFTS REEVALUATE. WHAT HAPPENS SATURDAY
NIGHT AND SUNDAY WILL STRONGLY AFFECT WHAT HAPPENS SUNDAY NIGHT.
HIGH TEMPERATURES SHOULD INCREASE AS MID LEVEL WARM AIR SURGES IN
OUR DIRECTION...SO HIGHS SHOULD RANGE FROM THE UPPER 80S TO LOW 90S
WITH LOWS IN THE UPPER 60S TO LOW 70S.
TUESDAY THROUGH THURSDAY...GENERAL NORTHWEST FLOW ALOFT WITH THE
UPPER LEVEL RIDGE STALLED OUT WEST. DESPITE HAVING A SURFACE RIDGE
IN PLACE...THE MID LEVEL BAROCLINIC ZONE WILL BE IN THE GENERAL
VICINITY. A FEW PERIODS OF SHOWERS AND THUNDERSTORMS ARE POSSIBLE
IN THIS PERIOD...BUT IT IS TOUGH TO NARROW DOWN WHICH PERIODS OR
LOCATIONS WITH THE NECESSARY MESOSCALE FEATURES POORLY DEFINED AT
THIS TIME RANGE. THUS...AM CARRYING SEVERAL PERIODS OF JUST SLIGHT
CHANCE POPS. TEMPERATURES TO SLOWLY RISE THROUGH THE PERIOD...WITH
HIGHS BY THURSDAY IN THE UPPER 80S TO MID 90S. LOWS IN THE UPPER
60S TO LOW 70S.
FRIDAY THERE ARE SOME LARGE DIFFERENCES IN THE MODELS. IN THE
ECMWF...THE UPPER LEVEL RIDGE FLATTENS AGAIN...AND A SHORTWAVE
APPEARS TO DIVE ACROSS THE MIDWEST ON FRIDAY. THIS...COMBINED WITH
THE MID LEVEL BAROCLINIC ZONE COULD PRODUCE A DECENT LIGHT TO
MODERATE RAIN EVENT. HOWEVER...THE GFS STILL KEEPS THE UPPER LEVEL
RIDGE STRONG WITH NO RAIN IN SIGHT...SO CONFIDENCE IS NOT HIGH.
SO...KEPT FORECAST MAINLY DRY WITH NEAR NORMAL TEMPERATURES.
LE
&&
.AVIATION... /ISSUED 1240 PM CDT FRI JUL 27 2012/
VFR WX IS EXPECTED THROUGH 06Z/28. THERE IS A POSSIBILITY OF
DIURNAL CONVECTION DEVELOPING LATE THIS AFTERNOON MAINLY EAST OF
THE MISSISSIPPI RIVER. IF CONVECTION DOES DEVELOP IT SHOULD BE
ISOLD IN NATURE BUT MAY CONTAIN TSRA. KDBQ COULD BE AFFECTED BUT
VCSH AND VCTS WAS LEFT OUT OF THE 18Z TAF. AFT 06Z/28 MAINLY VFR
WX IS EXPECTED. THERE IS A POSSIBILITY OF MVFR VSBYS DVLPG DUE TO
FG. THE 18Z TAFS REFLECT A POSSIBILITY OF VSBY RESTRICTION WITH
6SM ARND SUNRISE AT ALL SITES. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1240 PM CDT FRI JUL 27 2012
.UPDATE...
LATER THIS AFTERNOON COULD BE INTERESTING.
SFC OBS SHOW A TROF ACROSS WISCONSIN FROM JUST NORTH OF KMKE BACK
TO THE MISSISSIPPI RIVER BETWEEN KOEO AND KRZN. THIS TROF IS MUCH
SHARPER THAN DEPICTED IN ANY OF THE SHORT RANGE MODELS. A VORT MAX
ASSOCIATED WITH THE TROF HAS RESULTED IN SHRA/TSRA OVER MAINLY
EASTERN WISCONSIN BUT RADAR DOES SHOW SOME WEAK SHRA FURTHER WEST
IN CENTRAL WISCONSIN.
RAP TRENDS SHOW CONVECTIVE TEMPERATURES BEING IN THE LOWER 80S
ACROSS THE NORTHERN CWFA DURING THE AFTERNOON HOURS WHICH IS
COINCIDENT WITH THE FCST MAX TEMPERATURES. ALTHOUGH WEAKER THAN A
FEW HOURS AGO...THE RAP ALSO BEGINS TO DEVELOP SOME CONVERGENCE
OVER NORTHWEST ILLINOIS/SOUTHWEST WISCONSIN LATE THIS AFTERNOON.
ADDITIONALLY...THERE IS A WEAK THETA E GRADIENT OVER THE AREA
ALONG WITH THE PRESENCE OF THE VORT MAX.
THUS THERE IS A POSSIBILITY THAT SOME ISOLATED SHRA/TSRA COULD
DEVELOP LATE THIS AFTERNOON IF PARCELS CAN BE LIFTED TO THE LFC.
IF THIS OCCURS...CONVECTION WOULD DEVELOP SINCE THERE IS NO CAP
ABOVE THE LFC. THE AREA WOULD BE ROUGHLY EAST OF A LINE FROM KPDC
TO KSQI OR KVYS. TRENDS FOR THIS AREA WILL NEED TO BE MONITORED
CLOSELY DURING THE AFTERNOON FOR THE POSSIBILITY OF DIURNAL
CONVECTION DEVELOPING. IF CONVECTION DOES DEVELOP...IT SHOULD
DISSIPATE AROUND OR SHORTLY AFTER SUNSET. ..08..
&&
.AVIATION...
VFR WX IS EXPECTED THROUGH 06Z/28. THERE IS A POSSIBILITY OF
DIURNAL CONVECTION DEVELOPING LATE THIS AFTERNOON MAINLY EAST OF
THE MISSISSIPPI RIVER. IF CONVECTION DOES DEVELOP IT SHOULD BE
ISOLD IN NATURE BUT MAY CONTAIN TSRA. KDBQ COULD BE AFFECTED BUT
VCSH AND VCTS WAS LEFT OUT OF THE 18Z TAF. AFT 06Z/28 MAINLY VFR
WX IS EXPECTED. THERE IS A POSSIBILITY OF MVFR VSBYS DVLPG DUE TO
FG. THE 18Z TAFS REFLECT A POSSIBILITY OF VSBY RESTRICTION WITH
6SM ARND SUNRISE AT ALL SITES. ..08..
&&
.PREV DISCUSSION... /ISSUED 1014 AM CDT FRI JUL 27 2012/
UPDATE...
SHORTWAVE OVER NORTHEAST WISCONSIN WILL CONTINUE MOVING INTO
MICHIGAN THIS AFTERNOON. A VORT MAX DROPPING DOWN IS HELPING TO
MAINTAIN THE LOW CLOUDS ACROSS MN/WI. SATELLITE TRENDS INDICATE A
MORE CELLULAR NATURE TO THE CLOUDS IS OCCURRING SO THE SOUTHWARD
PROGRESS WILL SLOW. IMMEDIATE TRENDS ON SATELLITE THE PAST HOUR
SUGGEST SCT-BKN DIURNAL CU SHOULD DEVELOP OVER ROUGHLY THE NORTH
40 PERCENT OF THE CWFA FOR THE AFTERNOON WITH POSSIBLY SCT CU OVER
THE REMAINDER OF THE AREA.
REGARDLESS...THERE WILL BE MORE CLOUDS IN THE FAR NORTH/NORTHEAST
PARTS OF THE CWFA. SAID CLOUDS IN TURN WILL AFFECT TEMPERATURES
SOMEWHAT. DEEPER MIXING IS BEGINNING IN THE CLOUD FREE AREAS WHICH
SHOULD ALLOW DEW POINTS TO SLOWLY FALL THIS AFTERNOON.
TEMPERATURES SHOULD BE CLOSE TO NORMAL FOR MUCH OF THE CWFA THIS
AFTERNOON. THE POSSIBLE EXCEPTION MAY BE IN THE FAR SOUTHERN CWFA
WHERE SOME UPPER 80S MAY BE SEEN.
AN UPDATE REFLECTING THE CURRENT TRENDS SHOULD BE AVAILABLE BY
1030 AM. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1152 PM CDT THU JUL 26 2012
.AVIATION...
VFR CONDITIONS WILL BE OVER THE AREA THROUGH FRIDAY NIGHT. A WEAK
SURFACE TROF OVER THE AREA HAS ALLOWED WINDS TO BECOME LIGHT AND
VARIABLE. A FEW ISOLATED SHRA WERE OCCURRING NEAR THE TROF IN
SOUTHEAST IA AND OVER NW IL. THE TROF WILL MOVE SOUTHEAST
ALLOWING WINDS TO BECOME NORTHWEST AND INCREASE TO 6 TO 10KTS BY
FRIDAY MORNING AND THEN CONTINUING TO VEER TO THE NORTHEAST BY
FRIDAY EVENING. THE ISOLATED SHRA IS EXPECTED TO DISSIPATE WITHIN
THE NEXT SEVERAL HOURS.
DLF
&&
PREV DISCUSSION... /ISSUED 333 PM CDT THU JUL 26 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN 850MB COLD FRONT FROM NORTHERN WISCONSIN
SOUTHWEST INTO THE OKLAHOMA PANHANDLE. SEVERAL TROFS WERE ACROSS
THE NORTHERN PLAINS BEHIND THE 850MB COLD FRONT. RADAR/SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW DIURNAL CONVECTION HAS DEVELOPED
FROM SOUTHERN WISCONSIN INTO SOUTHEAST IOWA.
18Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM KVOK BACK TO KRSL. THIS
BOUNDARY MAY BE A VERY DIFFUSE COLD FRONT AS DEW POINTS QUICKLY
DROP INTO THE UPPER 50S AND LOWER 60S BEHIND THE BOUNDARY. AHEAD
OF THE FRONT/BOUNDARY DEW POINTS WERE IN THE LOW 70S.
SHORT TERM...TONIGHT AND FRIDAY
AN AREA OF DIFFERENTIAL HEATING ALONG THE FRONT/BOUNDARY HAS
ALLOWED CONVECTIVE TEMPERATURE TO BE ACHIEVED.
RAP TRENDS INDICATE THE CURRENT CONVECTION WILL REMAIN ISOLATED
OVER SOUTHEAST IOWA AND MORE SCATTERED FROM THE QUAD CITIES TO THE
NORTH AND EAST. RAP TRENDS INDICATE THIS CONVECTION WILL PERSIST
INTO THE LATE AFTERNOON AND EARLY EVENING IN THE FAR EASTERN AND
SOUTHERN SECTIONS OF THE CWFA.
THE APPROACHING SHORTWAVE ACROSS MINNESOTA IS ALLOWING CU TO
DEVELOP FROM SOUTHERN MINNESOTA INTO NORTHERN IOWA. RADAR SHOWS NO
CONVECTION AS YET BUT WITH PEAK HEATING OCCURRING CONVECTION MAY
DEVELOP IN THE NEXT COUPLE OF HOURS. IF THIS OCCURS...THEN IT MAY
GET INTO THE HWY 20 CORRIDOR THIS EVENING. NEARLY ALL CONVECTION
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNSET. HOWEVER...
CONVECTION DID PERSIST OVERNIGHT CLOSE TO THE SFC LOW AND UPPER
LOW. THUS IT IS POSSIBLE THAT SOME ISOLATED SHRA/TSRA MAY PERSIST
PAST MIDNIGHT THAT CATCHES THE NORTHEAST PART OF THE CWFA.
FRIDAY IS LOOKING TO BE QUITE NICE WITH TEMPERATURES NEAR NORMAL.
HUMIDITY LEVELS WILL ALSO BE LOW. ..08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
HIGH PRESSURE BUILDS INTO THE REGION FRIDAY NIGHT AND SATURDAY TO
KEEP THINGS QUIET BOTH PERIODS. HOWEVER...SATURDAY NIGHT AND SUNDAY
A NICE WARM AIR ADVECTION SURGE WITH A WEAK SHORTWAVE MOVES ACROSS
THE AREA TO BRING SOME PRECIPITATION CHANCES TO THE AREA.
TEMPERATURES WILL BE COOLER THAN WHAT WE HAVE HAD RECENTLY...WITH
HIGHS IN THE 80S TO AROUND 90 BOTH DAYS.
SUNDAY NIGHT THROUGH MONDAY NIGHT A STRONGER SHORTWAVE COMES ALONG
TO INTERACT WITH A WEAK 850MB BAROCLINIC ZONE TO BRING SOME
PRECIPITATION CHANCES TO THE AREA. THERE IS ROUGH AGREEMENT WITH
THE MODELS...BUT WITH TIMING DIFFERENCES TO ADD SOME CONFUSION.
HIGHS MONDAY TO BEGIN CREEPING UP...RISING INTO THE MID 80S TO LOW
90S.
TUESDAY THROUGH WEDNESDAY MODELS ARE IN GENERAL AGREEMENT THAT A
SURFACE RIDGE WILL BUILD ACROSS THE REGION...WHICH IS NOT ESPECIALLY
FAVORABLE FOR PRECIPITATION CHANCES...SO HAVE KEPT THOSE DRY OR AT
MOST SLIGHT CHANCE. HIGHS REMAIN IN THE 80S TO LOW 90S WITH THE
CONTINUING NORTHWEST FLOW ALOFT AND ENOUGH MOISTURE AT MID LEVELS TO
PRODUCE SOME MID CLOUDS.
THURSDAY WE HAVE A WEAK COLD FRONT AND HINTS AT AN UPPER LEVEL
SHORTWAVE TO MOVE THROUGH THE AREA...THOUGH MODELS HAVE A LOT OF
DIFFERENCES AND CONFIDENCE IS NOT VERY HIGH. HOWEVER...IT WAS
ENOUGH TO PUT IN TO CARRY SOME LOW END CHANCE POPS.
LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
719 PM MDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 510 PM MDT SAT JUL 28 2012
ISOLATED TO SCATTERED CONVECTIVE ACTIVITY IN THE VICINITY OF A
SURFACE TROUGH SHOULD CONTINUE MOVING TO THE EAST AND DISSIPATE
THROUGH THE EVENING AS THE TROUGH ALSO MOVES FURTHER SOUTH ACROSS
THE FORECAST AREA OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 224 PM MDT SAT JUL 28 2012
WV IMAGERY AND RUC H5 ANALYSIS SHOW STRONG RIDGE EXTENDING FROM THE
WESTERN US TO THE CENTRAL MISSISSIPPI RIVER VALLEY WITH A 597 HEIGHT
CENTER OVER NE OKLAHOMA. A PLUME OF MONSOONAL MOISTURE CONTINUES TO
ADVECT NORTH AND EAST ALONG THE WESTERN EXTENT OF THE RIDGE WITH
SEVERAL WEAK SHORTWAVE TROUGHS MOVING INTO THE TRI-STATE AREA FROM
THE WEST. AT THE SURFACE A COLD FRONT HAS STALLED OVER THE CWA AND
WILL ACT AS THE MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT THROUGH THE
NEXT FEW DAYS.
EARLY THIS AFTERNOON ISOLATED THUNDERSTORMS HAVE ALREADY DEVELOPED
ACROSS THE NE CWA NEAR MCCOOK ALONG THE FRONT WITH CUMULUS FURTHER
SOUTH AND EAST. RUC SOUNDINGS CONTINUE TO SHOW INVERTED-V TYPE
SOUNDINGS ALONG WITH DCAPE VALUES AROUND 1400 J/KG OR GREATER ACROSS
THE EASTERN PART OF THE CWA...WHICH SUPPORTS A THREAT FOR STRONG
DAMAGING WINDS WITH ANY THUNDERSTORMS THAT DEVELOP. PWAT VALUES ARE
ACTUALLY PRETTY GOOD WITH VALUES AROUND 1.4-1.5 AS A RESULT OF
MONSOONAL MOISTURE ADVECTING INTO THE MID LEVELS...SO THUNDERSTORM
COULD BE GOOD RAIN PRODUCERS THOUGH STORM MOTIONS AROUND 20KT SHOULD
KEEP FLASH FLOOD THREAT LIMITED. STORM THUNDERSTORM ACTIVITY THIS
EVENING SHOULD BE TIED TO DIURNAL PROCESSES WITH ACTIVITY ENDING
SHORTLY AFTER SUNRISE.
SUNDAY...THERE WILL BE VERY LITTLE CHANGE IN THE PATTERN AS THE
STATIONARY FRONT LINGERS OVER THE CWA...AND THE RIDGE REMAINS IN
PLACE. THUNDERSTORMS SHOULD REDEVELOP BY THE AFTERNOON WITH THE
FRONT AGAIN ACTING AS THE MAIN FOCUS FOR INITIATION. NAM SOUNDINGS
SHOW EVEN BETTER MID LEVEL MOISTURE SUNDAY AFTERNOON WITH PWAT
VALUES IN EXCESS OF 1.6...WHICH IS ANOMALOUSLY HIGH FOR THIS TIME
OF YEAR. CONSIDERING THAT AND VERY LIGHT STORM MOTIONS ON SUNDAY
IN THE ABSENCE OF ANY FLOW ALONG THE STATIONARY FRONT...THERE WILL
BE AN INCREASED THREAT OF FLASH FLOODING WITH ANY THUNDERSTORMS
THAT DO DEVELOP. COVERAGE WILL BE A QUESTION...SO I AM NOT
CONFIDENT ENOUGH TO ISSUE A FLASH FLOOD WATCH FOR SUNDAY
AFTERNOON/EVENING DURING THIS FORECAST CYCLE...HOWEVER THIS SHOULD
BE WATCHED GOING FORWARD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MDT SAT JUL 28 2012
UPPER RIDGE OVER THE SOUTHERN PLAINS WILL DRIFT WEST SOUTHWESTWARD
DURING THIS PERIOD. FAST MOVING SHORTWAVE TROUGHS RIDING THE RIDGE
MIGHT BE CLOSE ENOUGH TO PROVIDE WEAK LIFT FOR ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS...BUT CONFIDENCE IS LOW AND DO NOT
WARRANT MORE THAN A SLIGHT TO LOW CHANCE MENTION. TEMPERATURES
WILL CONTINUE TO BE ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 510 PM MDT SAT JUL 28 2012
VFR CONDITIONS WILL CONTINUE AT KMCK AND KGLD THROUGH THE TAF
PERIOD. ISOLATED TO SCATTERED THUNDERSTORMS IN THE VICINITY OF A
SURFACE TROUGH THAT WILL MOVE SOUTH THROUGH THE AREA OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...024
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS TOPEKA KS
546 AM CDT FRI JUL 27 2012
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
THE RAP AND NAM SHOW MID LEVEL DRY AIR ADVECTING FROM THE NORTH
INTO NORTHEAST KS WITH THE SFC RIDGE. THEREFORE THINK THE
ISOLATED CONVECTION AROUND HIAWATHA WILL BE SHORT LIVED. LATEST
11U-1.9U SATELLITE IMAGES SHOWS ACCUS IS BECOMING LESS
PREDOMINATE ACROSS SOUTHERN NEB AS WELL. THEREFORE WITH RISING MID
LEVEL HEIGHTS ANTICIPATE THROUGH 12Z SAT...VFR CONDITIONS ARE
EXPECTED TO PERSIST.
WOLTERS
&&
.PREV DISCUSSION... /ISSUED 311 AM CDT FRI JUL 27 2012/
TODAY/TONIGHT...A WEAK FRONTAL BOUNDARY ASSOCIATED WITH A STRONG
SHORTWAVE TROUGH OVER THE WESTERN GREAT LAKES IS HELPING TO
GENERATE SHALLOW ISOLATED CONVECTION OVER N MO AND NE KS. MODELS
SUGGEST THIS ACTIVITY WILL BE SHORT LIVED AND SHOULD GRADUALLY
DISSIPATE SHORTLY AFTER SUNRISE AS THE ASCENT FROM THE UPPER
DISTURBANCE IS DISPLACED FURTHER TO THE EAST. OTHERWISE SFC HIGH
PRESSURE BUILDS INTO THE MO RIVER VALLEY TODAY INTO TONIGHT. SFC
WIND TRAJECTORIES WILL BE FROM THE NORTH UPON THE BOUNDARY PASSAGE
AND AS THE HIGH BRIEFLY SETTLES IN. TEMPERATURES THIS AFTERNOON
WILL BE SIMILAR TO YESTERDAYS READINGS...WITH THE WARMEST
CONDITIONS ALONG AND SOUTH OF THE INTERSTATE 70 CORRIDOR.
OVERNIGHT LOWS WILL COOL INTO THE UPPER 60S TO LOWER 70S...WHICH
WILL BE THE COOLEST READINGS REMAINING IN THE NEXT 7 DAYS.
SATURDAY/SUNDAY...THE SFC HIGH MOVES OFF THE EAST WITH SOUTHERLY
WINDS RETURNING. HOT TEMPERATURES ARE EXPECTED TO ALSO RETURN OVER
THE WEEKEND AS UPPER RIDGING BUILDS INTO THE CENTRAL PLAINS. THE H85
THERMAL AXIS TENDS TO SET NEAR OR OVER THE CWA DURING THIS
PERIOD...TRANSLATING TO READINGS REACHING THE 99-107 RANGE. NO
PLANS ATTM FOR HEAT HEADLINES...BUT CERTAINLY THIS IS SOMETHING THAT
WILL NEED TO BE CLOSELY MONITORED IN SUBSEQUENT FORECASTS. SUNDAY
COULD POTENTIALLY BE EVEN WARMER THAN CURRENTLY ADVERTISED AS
WESTERLY H85 DOWNSLOPE COMPONENT SETS UP OVER KANSAS. LIKEWISE...HAVE
ALSO INSERTED SLIGHT CHANCE OF PRECIPITATION ON SUNDAY AFTERNOON AS
CONVECTIVE TEMPERATURE SHOULD EASILY BE EXCEEDED. ANY CONVECTION
WOULD LIKELY BE ISO/SCT IN NATURE...SHORT-LIVED...AND CLOSELY TIED
TO THE SFC THERMAL AXIS DURING THE 20-01Z TIME FRAME. POINT
SOUNDINGS WOULD SUGGEST ANOTHER POTENTIAL MICROBURST CONCERN WITH
IMPRESSIVE INVERTED-V PROFILE...IF CONVECTION INDEED DEVELOPS DURING
THE AFTERNOON.
MONDAY AND BEYOND...MINUS ANY WEAK PERTURBATIONS PASSING THROUGH
NEBRASKA ON THE SOUTHERN PERIPHERY OF THE UPPER JET THAT MAY YIELD
VERY MARGINAL PRECIPITATION CHANCES...THE UPPER RIDGE APPEARS TO
REMAIN FIRMLY IN PLACE OVER KANSAS THROUGH THE EXTENDED
FORECAST...RESULTING IN HOT AND DRY WEATHER CONTINUING. HIGH
TEMPERATURES IN THE UPPER 90S TO LOWER 100S SEEM QUITE REASONABLE.
BLAIR
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
158 AM EDT FRI JUL 27 2012
.UPDATE...
ISSUED AT 1250 AM EDT FRI JUL 27 2012
CLOUD TOPS HAVE REALLY STARTED TO WARM...SO THE THREAT INSIDE THE
WATCH AREA HAS QUICKLY DISAPPEARED. THUS...THE WATCH HAS BEEN
CANCELLED. STILL A THREAT FOR SOME FLOODING WITH THE HEAVY RAIN NORTH
OF I-64 ONGOING...BUT EVEN THIS THREAT WILL DIMINISH WITHIN AN HOUR
OR TWO. HRRR/RUC HAS MUCH OF THE ONGOING SHOWER/STORM ACTIVITY
FALLING APART...WHICH SEEMS SUPPORTIVE BASED ON THE LATEST RADAR
IMAGERY SHOWING THE LINE OF SHOWERS REALLY BREAKING UP AS THEY ENTER
THE I-75 CORRIDOR. STILL GOING TO CARRY SOME ISOLATED SHOWERS OR
STORMS FOR THE REST OF THE NIGHT AS THE COLD POOL COULD STILL IGNITE
A SHOWER OR TWO.
UPDATE ISSUED AT 1042 PM EDT THU JUL 26 2012
CONVECTION CONTINUES TO FIRE ALONG A MODEST LOW LEVEL JET OCCURRING
ACROSS KENTUCKY. THE SEVERE CONVECTION HAS BEEN GRADUALLY WINDING
DOWN NORTH OF I-64 OVERALL...ALTHOUGH A FEW CELLS CONTINUE TO GET
STRONG OCCASIONALLY. ALONG AND SOUTH OF THE MOUNTAIN PARKWAY...THE
AIR MASS HAS NOT BEEN TAPPED OUT YET...SO WILL HOLD ONTO THE WATCH.
SOME STORMS ARE TRAINING NORTH OF I-64 IN THE PAST HOUR...SO WILL
HAVE TO WATCH FOR THE POTENTIAL OF SOME MINOR FLOODING IN POOR
DRAINAGE AREAS. DEEPER CONVECTION IS ALSO FIRING UP ACROSS CENTRAL
KENTUCKY...AND THIS CONTINUES TO SLOWLY SAG SOUTH WITH TIME...WHILE
INDIVIDUAL CELLS AND CLUSTERS MOVE EAST. DO EXPECT A GRADUAL WEAKENING
TREND AS THEY HEAD TOWARDS I-75...SO LOCALLY HEAVY RAINFALL MAY BE
THE BIGGEST THREAT FROM THESE BY THE TIME THEY MAKE IT INTO THE AREA
AFTER MIDNIGHT.
UPDATE ISSUED AT 741 PM EDT THU JUL 26 2012
STRONG TO SEVERE CONVECTION HAS MADE IT INTO THE I-64 CORRIDOR...WITH
MORE TRAILING CONVECTION OFF TO WSW. SO FAR...THIS LINE HAS ONLY
SAGGED SOUTHEAST SLIGHTLY IN THE PAST HOUR...HOWEVER THIS MAY MAKE
BETTER PROGRESS IN THE NEXT FEW HOURS IF COLD POOLING CAN GET GOING.
HAVE UPDATED THE FORECAST TO INCLUDE CATEGORICAL POPS IN THE
BLUEGRASS...AND THEN BLENDED INTO THE EXISTING TIMING FOR NOW UNTIL
IT BECOMES MORE CLEAR IF THE STORMS MAKE MORE OF A SOUTHEAST SAG WITH
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM EDT THU JUL 26 2012
CHALLENGING FORECAST FOR THE SHORT TERM. BEST DYNAMICS AND FORCING REMAIN
TO THE NORTH OF OUR AREA AT THIS TIME...BUT WITH CONTINUED INSOLATION
FOR SEVERAL MORE HOURS AIR MASS OVER EAST KY WILL CONTINUE TO
DESTABILIZE. LATEST GOES SOUNDER SHOWS LIFTED INDICES FROM -3 TO -5
OVER AREA...AND PLENTY OF LOW LEVEL MOISTURE IS IN PLACE WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S.
HOWEVER THE WINDOW FOR SEVERE WEATHER IN EAST KY LOOKS VERY LIMITED
DUE TO TIMING OF WHEN CONVECTION SHOULD ENTER THE AREA. BEST ESTIMATE
AT THIS TIME IS FOR CONVECTION TO ENTER THE FAR NORTH AROUND 8 PM.
WITH BEST FORCING REMAINING NORTH OF THE AREA AND THE FACT THAT WE
WILL BE LOSING DAYTIME HEATING DO NOT EXPECT CONVECTION THAT ENTERS
OUR AREA TO MAINTAIN SEVERE CHARACTERISTICS...IF IT IS SEVERE TO
BEGIN WITH...VERY FAR SOUTH AND EAST INTO THE FORECAST AREA.
THERE IS ALSO A WIDE RANGE OF MODEL SOLUTIONS FOR THE NEAR
TERM AS TO TIMING AND EXTENT OF SHOWERS AND THUNDERSTORMS TONIGHT AND
AGAIN ON FRIDAY INTO FRIDAY EVENING. FOR THE VERY NEAR TERM HAD BEEN
FAVORING THE HRRR WHICH HAD BEEN VERY CONSISTENT WITH SEVERAL RUNS IN
A ROW SHOWING THE SHOWERS AND THUNDERSTORMS MOVING INTO THE FAR
NORTH PART OF OUR AREA AROUND 01Z. HOWEVER THE LATEST...15Z RUN IS
KEEPING MOST OF OUR AREA DRY THROUGH 06Z. FOR NOW HAVE GONE WITH A
BLEND OF NEIGHBORING FORECAST OFFICE TIMING...CURRENT RADAR
TRENDS...ANALYSIS AND MODEL BLENDS.
ALL CONVECTION TONIGHT WILL BE PRE FRONTAL...AND WITH THE FRONT YET
TO PUSH INTO OUR AREA ON FRIDAY...ADDITIONAL THUNDERSTORMS WILL BE
POSSIBLE YET AGAIN...AS UPPER SHORT WAVE TROF MOVES ACROSS THE LAKES
AND OH VALLEY. THE 12Z NAM IS THE MOST AGGRESSIVE WITH THIS
IDEA...AND SPC HAS PLACED OUR ENTIRE AREA IN A SLIGHT RISK FOR
FRIDAY. THERE IS CONSIDERABLE QUESTION AS TO HOW MUCH INSTABILITY
WILL BE PRESENT ON FRIDAY THOUGH. WILL CARRY THUNDERSTORM CHANCES ON
FRIDAY FOR ONGOING MORNING CONVECTION AND ALSO CHANCE FOR
REDEVELOPMENT IN THE AFTERNOON...AND WILL CARRY SLIGHT CHANCE TO
CHANCE INTO FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU JUL 26 2012
THE PERIOD WILL BEGIN WITH AN UPPER LEVEL SHORTWAVE TROUGH PUSHING
EAST OF THE AREA WITH RISING HEIGHTS ACROSS THE REGION ON SAT. UPPER
LEVEL RIDGING WILL GENERALLY DOMINATE THE WEEKEND WITH SFC HIGH
PRESSURE BUILDING INTO THE OHIO VALLEY BEFORE SHIFTING EAST AT THE
END OF WEEKEND. HOWEVER...BY EARLY NEXT WEEK THE RIDGE BECOME
ESTABLISHED A BIT FURTHER SOUTHWEST IN THE SOUTHERN PLAINS WITH THE
REGION ENDING UP IN NW FLOW ALOFT BETWEEN THIS RIDGE AND TROUGHING
OVER THE GREAT LAKES...NORTHEAST AND DOWN ALONG THE EASTERN
SEABOARD. THIS OVERALL PATTERN WILL REMAIN UNCHANGED TROUGH THE END
OF THE PERIOD.
THIS SCENARIO WILL LEAD TO A RATHER QUIET AND PLEASANT PATTERN OVER
THE WEEKEND AND YIELD MORE ACTIVE WEATHER WITH THE THREAT OF
CONVECTION. THIS CONVECTION SHOULD LARGELY HAVE A DIURNAL COMPONENT
TO IT...BUT MCS NOCTURNAL CONVECTION WILL ALSO BE POSSIBLE. TIMING OF
THE THE GREATEST THREAT OF NOCTURNAL CONVECTION IS LOW ATTM...ALTHOUGH
MODELS TO POINT TOWARD SOME OF THIS POSSIBLY OCCURRING ON MON NIGHT.
WE WENT WITH SLIGHT CHANCE POPS IN THE SW LATE ON SUN NIGHT WITH
CHANCE POPS WITH THE DIURNAL FLAVOR FROM THEN ON.
AS FOR TEMPS...MAX TEMPS SHOULD AVERAGE NEAR NORMAL THROUGH THE
PERIOD...WITH THE GREATEST DEPARTURE IN OVERNIGHT LOWS FROM TUE NIGHT
ON. MIN T ON SAT NIGHT...IN THE LOW TO MID 60S MAY BE THE LOWEST
OBSERVED SO FAR THIS MONTH IN VALLEY LOCATIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 157 AM EDT FRI JUL 27 2012
COLD POOL HAS PUSHED ACROSS THE TAF SITES WITH A BRIEF GUSTS TO
AROUND 20 TO 25 KNOTS. THE RAIN CHANCES WILL COME TO AN END OVER THE
NEXT 30 TO 40 MINUTES. WITHOUT MUCH RAINFALL AT THE TAF
SITES...REALLY NOT ANTICIPATED MUCH FOG OVERNIGHT. VFR CONDITIONS
WILL THEN DOMINATE THROUGH MUCH OF FRIDAY. A COLD FRONT DROPPING IN
FROM THE NORTH TOMORROW EVENING WILL BRING ANOTHER CHANCE FOR SHOWERS
AND STORMS AFTER 00Z TOMORROW EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM....JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1250 AM EDT FRI JUL 27 2012
.UPDATE...
ISSUED AT 1250 AM EDT FRI JUL 27 2012
CLOUD TOPS HAVE REALLY STARTED TO WARM...SO THE THREAT INSIDE THE
WATCH AREA HAS QUICKLY DISAPPEARED. THUS...THE WATCH HAS BEEN
CANCELLED. STILL A THREAT FOR SOME FLOODING WITH THE HEAVY RAIN NORTH
OF I-64 ONGOING...BUT EVEN THIS THREAT WILL DIMINISH WITHIN AN HOUR
OR TWO. HRRR/RUC HAS MUCH OF THE ONGOING SHOWER/STORM ACTIVITY
FALLING APART...WHICH SEEMS SUPPORTIVE BASED ON THE LATEST RADAR
IMAGERY SHOWING THE LINE OF SHOWERS REALLY BREAKING UP AS THEY ENTER
THE I-75 CORRIDOR. STILL GOING TO CARRY SOME ISOLATED SHOWERS OR
STORMS FOR THE REST OF THE NIGHT AS THE COLD POOL COULD STILL IGNITE
A SHOWER OR TWO.
UPDATE ISSUED AT 1042 PM EDT THU JUL 26 2012
CONVECTION CONTINUES TO FIRE ALONG A MODEST LOW LEVEL JET OCCURRING
ACROSS KENTUCKY. THE SEVERE CONVECTION HAS BEEN GRADUALLY WINDING
DOWN NORTH OF I-64 OVERALL...ALTHOUGH A FEW CELLS CONTINUE TO GET
STRONG OCCASIONALLY. ALONG AND SOUTH OF THE MOUNTAIN PARKWAY...THE
AIR MASS HAS NOT BEEN TAPPED OUT YET...SO WILL HOLD ONTO THE WATCH.
SOME STORMS ARE TRAINING NORTH OF I-64 IN THE PAST HOUR...SO WILL
HAVE TO WATCH FOR THE POTENTIAL OF SOME MINOR FLOODING IN POOR
DRAINAGE AREAS. DEEPER CONVECTION IS ALSO FIRING UP ACROSS CENTRAL
KENTUCKY...AND THIS CONTINUES TO SLOWLY SAG SOUTH WITH TIME...WHILE
INDIVIDUAL CELLS AND CLUSTERS MOVE EAST. DO EXPECT A GRADUAL WEAKENING
TREND AS THEY HEAD TOWARDS I-75...SO LOCALLY HEAVY RAINFALL MAY BE
THE BIGGEST THREAT FROM THESE BY THE TIME THEY MAKE IT INTO THE AREA
AFTER MIDNIGHT.
UPDATE ISSUED AT 741 PM EDT THU JUL 26 2012
STRONG TO SEVERE CONVECTION HAS MADE IT INTO THE I-64 CORRIDOR...WITH
MORE TRAILING CONVECTION OFF TO WSW. SO FAR...THIS LINE HAS ONLY
SAGGED SOUTHEAST SLIGHTLY IN THE PAST HOUR...HOWEVER THIS MAY MAKE
BETTER PROGRESS IN THE NEXT FEW HOURS IF COLD POOLING CAN GET GOING.
HAVE UPDATED THE FORECAST TO INCLUDE CATEGORICAL POPS IN THE
BLUEGRASS...AND THEN BLENDED INTO THE EXISTING TIMING FOR NOW UNTIL
IT BECOMES MORE CLEAR IF THE STORMS MAKE MORE OF A SOUTHEAST SAG WITH
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM EDT THU JUL 26 2012
CHALLENGING FORECAST FOR THE SHORT TERM. BEST DYNAMICS AND FORCING REMAIN
TO THE NORTH OF OUR AREA AT THIS TIME...BUT WITH CONTINUED INSOLATION
FOR SEVERAL MORE HOURS AIR MASS OVER EAST KY WILL CONTINUE TO
DESTABILIZE. LATEST GOES SOUNDER SHOWS LIFTED INDICES FROM -3 TO -5
OVER AREA...AND PLENTY OF LOW LEVEL MOISTURE IS IN PLACE WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S.
HOWEVER THE WINDOW FOR SEVERE WEATHER IN EAST KY LOOKS VERY LIMITED
DUE TO TIMING OF WHEN CONVECTION SHOULD ENTER THE AREA. BEST ESTIMATE
AT THIS TIME IS FOR CONVECTION TO ENTER THE FAR NORTH AROUND 8 PM.
WITH BEST FORCING REMAINING NORTH OF THE AREA AND THE FACT THAT WE
WILL BE LOSING DAYTIME HEATING DO NOT EXPECT CONVECTION THAT ENTERS
OUR AREA TO MAINTAIN SEVERE CHARACTERISTICS...IF IT IS SEVERE TO
BEGIN WITH...VERY FAR SOUTH AND EAST INTO THE FORECAST AREA.
THERE IS ALSO A WIDE RANGE OF MODEL SOLUTIONS FOR THE NEAR
TERM AS TO TIMING AND EXTENT OF SHOWERS AND THUNDERSTORMS TONIGHT AND
AGAIN ON FRIDAY INTO FRIDAY EVENING. FOR THE VERY NEAR TERM HAD BEEN
FAVORING THE HRRR WHICH HAD BEEN VERY CONSISTENT WITH SEVERAL RUNS IN
A ROW SHOWING THE SHOWERS AND THUNDERSTORMS MOVING INTO THE FAR
NORTH PART OF OUR AREA AROUND 01Z. HOWEVER THE LATEST...15Z RUN IS
KEEPING MOST OF OUR AREA DRY THROUGH 06Z. FOR NOW HAVE GONE WITH A
BLEND OF NEIGHBORING FORECAST OFFICE TIMING...CURRENT RADAR
TRENDS...ANALYSIS AND MODEL BLENDS.
ALL CONVECTION TONIGHT WILL BE PRE FRONTAL...AND WITH THE FRONT YET
TO PUSH INTO OUR AREA ON FRIDAY...ADDITIONAL THUNDERSTORMS WILL BE
POSSIBLE YET AGAIN...AS UPPER SHORT WAVE TROF MOVES ACROSS THE LAKES
AND OH VALLEY. THE 12Z NAM IS THE MOST AGGRESSIVE WITH THIS
IDEA...AND SPC HAS PLACED OUR ENTIRE AREA IN A SLIGHT RISK FOR
FRIDAY. THERE IS CONSIDERABLE QUESTION AS TO HOW MUCH INSTABILITY
WILL BE PRESENT ON FRIDAY THOUGH. WILL CARRY THUNDERSTORM CHANCES ON
FRIDAY FOR ONGOING MORNING CONVECTION AND ALSO CHANCE FOR
REDEVELOPMENT IN THE AFTERNOON...AND WILL CARRY SLIGHT CHANCE TO
CHANCE INTO FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU JUL 26 2012
THE PERIOD WILL BEGIN WITH AN UPPER LEVEL SHORTWAVE TROUGH PUSHING
EAST OF THE AREA WITH RISING HEIGHTS ACROSS THE REGION ON SAT. UPPER
LEVEL RIDGING WILL GENERALLY DOMINATE THE WEEKEND WITH SFC HIGH
PRESSURE BUILDING INTO THE OHIO VALLEY BEFORE SHIFTING EAST AT THE
END OF WEEKEND. HOWEVER...BY EARLY NEXT WEEK THE RIDGE BECOME
ESTABLISHED A BIT FURTHER SOUTHWEST IN THE SOUTHERN PLAINS WITH THE
REGION ENDING UP IN NW FLOW ALOFT BETWEEN THIS RIDGE AND TROUGHING
OVER THE GREAT LAKES...NORTHEAST AND DOWN ALONG THE EASTERN
SEABOARD. THIS OVERALL PATTERN WILL REMAIN UNCHANGED TROUGH THE END
OF THE PERIOD.
THIS SCENARIO WILL LEAD TO A RATHER QUIET AND PLEASANT PATTERN OVER
THE WEEKEND AND YIELD MORE ACTIVE WEATHER WITH THE THREAT OF
CONVECTION. THIS CONVECTION SHOULD LARGELY HAVE A DIURNAL COMPONENT
TO IT...BUT MCS NOCTURNAL CONVECTION WILL ALSO BE POSSIBLE. TIMING OF
THE THE GREATEST THREAT OF NOCTURNAL CONVECTION IS LOW ATTM...ALTHOUGH
MODELS TO POINT TOWARD SOME OF THIS POSSIBLY OCCURRING ON MON NIGHT.
WE WENT WITH SLIGHT CHANCE POPS IN THE SW LATE ON SUN NIGHT WITH
CHANCE POPS WITH THE DIURNAL FLAVOR FROM THEN ON.
AS FOR TEMPS...MAX TEMPS SHOULD AVERAGE NEAR NORMAL THROUGH THE
PERIOD...WITH THE GREATEST DEPARTURE IN OVERNIGHT LOWS FROM TUE NIGHT
ON. MIN T ON SAT NIGHT...IN THE LOW TO MID 60S MAY BE THE LOWEST
OBSERVED SO FAR THIS MONTH IN VALLEY LOCATIONS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 741 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH MOST OF THE
EVENING...AS ONGOING CONVECTION ALONG THE I-64 CORRIDOR LOOKS TO STAY
NORTH FOR A WHILE. SOUTHWEST WINDS WILL CONTINUE TO GUST IN THE
BROADER VALLEYS TO BETWEEN 15 AND 20 KTS THIS EVENING...BEFORE
DIMINISHING. THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE
FORECAST AREA FROM NORTH TO SOUTH DURING THE OVERNIGHT
PERIOD...ALTHOUGH CONFIDENCE IS NOT VERY HIGH WITH HOW MUCH THEY WILL
HOLD TOGETHER. ASSUMING THUNDERSTORMS DO HOLD TOGETHER...EXPECT IFR
TO MVFR CONDITIONS IN FOG AND LOW CLOUDS TO PERSIST INTO THE DAY ON
FRIDAY...WITH SCATTERED THUNDERSTORMS POSSIBLE ONCE AGAIN DURING THE
AFTERNOON HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM....JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
925 PM EDT SAT JUL 28 2012
.SYNOPSIS...
AN UPPER-LEVEL DISTURBANCE WILL CROSS THE REGION OVERNIGHT.
LOW PRESSURE WILL PERSIST THROUGH MUCH OF NEXT WEEK AND WILL
PROVIDE DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH SUNDAY/...
TROF AXIS FINALLY HAS PUSHED ONTO THE ERN SHORE. TSRA IN SERN CWFA
STARTING TO WANE W/ THE SUBSIDENCE FM WLY FLOW...LOSS OF SFC
CNVGNC AND SUNSHN. THE REST OF SVR TSTM WATCH WL BE ALLOWED TO
EXPIRE AT 10 PM.
THE UPPER-LEVEL SYSTEM WILL PASS THROUGH THE REGION LATE TONIGHT.
THE SETTING SUN HAS REALLY TAKEN A TOLL ON ANY PCPN ASSOCD WITH
THIS FEATURE. JUST A CPL OF DECAYING TSRA LEFT. DOUBT ANYTHING WL
SURVIVE THE TRIP OVR THE MTNS. LTST HRRR GNLY CONCURS. WL LEAVE
CHC POPS IN THE MTNS TIL MIDNGT.
GOING TEMP FCST SUPPORTED BY LAMP AND OBSVD DEWPTS. NO CHGS REQD
TO MIN-T.
UPPER-LEVEL RIDGING IS EXPECTED ON SUNDAY BEHIND THE SHORTWAVE
TROUGH. NORTHWEST FLOW WILL USHER IN SOMEWHAT DRIER AIR FOR MOST
LOCATIONS...ALLOWING FOR SOME SUNSHINE AND SEASONABLY WARM
CONDITIONS. MAX TEMPS WILL RANGE FROM THE 70S IN THE MOUNTAINS TO
NEAR 90 IN WASHINGTON/BALTIMORE. WARM CONDITIONS WILL CAUSE A SCT-
BKN CU DECK...AND THERE MAY BE ENOUGH INSTABILITY FOR ISOLATED
SHOWERS AND TSTMS NEAR AND EAST OF THE BLUE RIDGE MOUNTAINS.
HOWEVER...MUCH OF THE TIME WILL BE DRY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
SHWRS AND TSTMS WILL WANE SUN EVE AS SHRTWV TROF RESPONSIBLE FOR
THEIR GENERATION MOVES E AND SHRTWV RDGG DOMINATES. A SECOND TROF
WILL APRCH EARLY MON MRNG AND MAY LEAD TO MRNG PCPN FOR A LRG
PORTION OF THE FCST AREA. THIS WAVE DOES NOT APPEAR FAVORABLY
TIMED...SO STG CNVCTN NOT XPCD ATTM.
H5 TROF WILL BCM ENTRENCHED ALONG APLCNS THRU TUE NGT WITH MOIST
BNDRY LYR PERSISTING. SHWRS AND TSTMS CAN BE XPCD PERIODICALLY
DURG THIS TIME.
MAXIMA WILL BE NR OR JUST ABV CLIMATOLOGICAL NORMS IN THE UPR 80S.
MINIMA WILL DEPEND ON AMT OF CLRG OVNGT...AS BNDRY LYR MSTR WILL
RMN HIGH.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
H5 TROF XPCD TO PERSIST ALONG THE E COAST FOR MUCH OF THE COMING
WK. SHRTWV TROFS WILL ACT UPON THE MOIST LOW-LVL AMS TO GENERATE
DAILY ROUNDS OF SHWRS AND TSTMS THRU MUCH OF THE EXTENDED PD.
MAXIMA WILL BE IN THE UPR 80S-LWR 90S EACH DAY...WITH MINIMA IN
THE MID 60S-LWR MID 70S OWING TO CLD CVR AND HIGH BNDRY LYR MSTR
CONTENT.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED MOST OF THE TIME THROUGH SUNDAY.
ISOLATED SHOWERS/TSTMS ARE POSSIBLE AT THE EASTERN TERMINALS
SUNDAY AFTERNOON.
PERSISTENT WARM AND MOIST AMS AT THE SFC AND LOW PRESSURE ALOFT
WILL PROMOTE DAILY CHCS FOR TSTMS AT THE TERMINALS THRU MUCH OF
THE COMING WK.
&&
.MARINE...
A FEW TSRA REMAIN ON THE WATERS...MAINLY MID BAY AND LWR PTMC.
TRENDS DECREASING...BUT MAY STILL HV GUSTY WINDS AND A LTNG THREAT
THRU MIDNGT. OTRW...WINDS WILL REMAIN BELOW SCA CRITERION THROUGH
SUNDAY. ISOLATED SHOWERS/TSTMS ARE POSSIBLE DURING THE DAY.
PERSISTENT WARM AND MOIST AMS AT THE SFC AND LOW PRESSURE ALOFT
WILL PROMOTE DAILY CHCS FOR TSTMS NR THE WATERS THRU MUCH OF THE
COMING WK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...HTS/LASORSA
SHORT TERM...KRAMAR
LONG TERM...KRAMAR
AVIATION...HTS/LASORSA/KRAMAR
MARINE...HTS/KRAMAR
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
200 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TODAY AND SLOWLY MOVE THROUGH
THE REGION TONIGHT. HIGH PRESSURE RETURNS SATURDAY AND REMAINS
INTO THE BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
...UPDATE TO INCLUDE SEVERE T-STORM WATCH FOR PORTIONS OF CENTRAL
VIRGINIA UNTIL 10 PM... PREVIOUS DISCUSSION FOLLOWS.
COLD FRONT CURRENTLY DRAPED FROM THE ERN GREAT LAKES ACROSS THE
PA/NY BORDER WILL SAG SOUTHEAST TOWARD THE CENTRAL MID ATLANTIC
TODAY. 12Z MODIFIED SOUNDING STILL SUPPORTS HIGH TEMPS IN THE MID
90S AT IAD...SO HIGH TEMP FORECAST FOR UPPER 90S IN DC/BALTIMORE
AREA STILL LOOKS VALID. TEMPS RUNNING A FEW DEGREES COOLER WEST OF
THE METRO AREAS DUE TO DEBRIS CLOUDS...BUT CLEARING TREND IS IN
PLACE LATE THIS MORNING.
SCATTERED SHOWERS HAVE DEVELOPED ALONG A PRE-FRONTAL TROUGH OVER
CENTRAL WV. 12Z NAM/09Z SREF SUPPORT THIS ACTIVITY BUILDING AND
MOVING EWD TOWARDS THE CWA THIS AFTN...BUT CLOUDS IN PLACE OVER WV
MAY LIMIT COVERAGE AND SEVERE THREAT. HRRR DOES NOT SUPPORT THIS
DEVELOPMENT...BUT INSTEAD FOCUSES CONVECTIVE INITIATION OVER THE
MOUNTAINS AND PIEDMONT EARLY THIS AFTERNOON. 12Z IAD SOUNDING
INDICATES SUFFICIENT SHEAR OVER THE REGION...AND IF SURFACE TEMPS
WARM AS FORECAST A 750MB CAP SHOULD BE BROKEN ALLOWING SB CAPE TO
REACH 2600 J/KG. SPC HAS A SLIGHT RISK OVER MOST OF VA AND MD EAST
OF THE BLUE RIDGE TODAY. MAIN THREAT WOULD BE DAMAGING
WINDS...ALTHOUGH A LARGE HAIL THREAT EXISTS AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
COLD FRONT SLOWLY SAG SOUTH TOWARD SERN VA WITH UPR TROUGH
REMAINING BACK OVER THE OH VLY. SHOULD SEE A BREAK IN PRECIP FOR
I-95 AND WEST /NOTE THE WEST/ BY THE EVENING...WITH PRECIP
PERSISTING EAST/SOUTH OF I-95 WELL INTO THE OVERNIGHT. MIN TEMPS MID
60S PIEDMONT AND WEST...LOW TO MID 70S I-95 AND EAST.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE ULTRA HIGH TEMPS WL BE HELD AT BAY DURG THE XTND PD. THIS IS
FREQUENTLY THE TIME OF YR WHEN THE "FOUR CORNERS HIGH" DVLPS OVR THE
SWRN U.S. ...AND THIS APPEARS TO BE THE CASE IN ALL OF THE XTND
MDLS. BECAUSE OF THIS THE ERN U.S. WL BE UNDER A SLT UPPER TROF.
THIS WL KEEP THE REALLY HOT WX...AND THE 70+ DWPTS...AT BAY FOR
THE FINAL DAYS OF JUL AND THE BEGINNING OF AUG. IN THE MID
ATLC...XPCT MOST OF THE XTND PD TO HV HIGH TEMPS IN THE MU80S.
LOWS RANGING FM THE L70S IN THE CITIES TO THE U50S IN THE
HIGHLANDS...BUT THE MAJORITY OF WL HV LOWS IN THE M60S.
THERE ISN`T MUCH TO HANG ONTO REGARDING POP CHCS. W/ ERN TROF IT
IS PSBL THAT A BNDRY COULD DVLP SOMETIME NEXT WK AND SERVE AS A
FOCUS FOR TSTM DVLPMNT...OTHERWISE SCT AFTN TSTMS IS THE BEST CHC
FOR RAFL.
ONE DAY CLOSER TO THE END OF THE MONTH...THIS RMNS THE WARMEST JUL
(AVG TEMP) IN DC ON RECORD. IT`S AMAZING THAT #2 AND 3 ARE THE PRVS
TWO YRS...EVEN THO RECORDS GO BACK TO 1871. BWI - THIS JUL IS IN
THE #2 SLOT...0.2 DEGS BEHIND 2010. THIS JUL IS ALSO #1 FOR
IAD...0.5 DEG AHD OF LAST YR.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR THIS MORNING. BRIEF LIGHT RAIN EXPECTED AT KMRB BEFORE 13Z.
THUNDERSTORMS/POTENTIAL PERIODS OF IFR CONDS THIS AFTERNOON AHEAD
OF A COLD FRONT. SWLY/WLY FLOW AROUND 10 KT TODAY. COLD FRONT
SLOWLY CROSSES TONIGHT WITH VFR CONDITIONS UNDER MID LEVEL CLOUDS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS SUNDAY BEFORE MOVING OFF
THE COAST FOR THE FIRST PART OF NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL INCREASE THE CHANCES FOR SHOWERS/TSTMS DURING THIS
TIME...HOWEVER NO WIDESPREAD SVR OUTBRK CAN BE SEEN ON THE
HORIZON.
&&
.MARINE...
WLY/SWLY FLOW AROUND 10 KT CONTINUE THROUGH TODAY. SCATTERED
THUNDERSTORMS EXPECTED LATE THIS AFTERNOON WELL INTO THE OVERNIGHT
WITH A DAMAGING WIND THREAT AHEAD/ALONG A SLOW MOVING COLD FRONT.
SURFACE HIGH PRESSURE WILL BUILD OVER THE WATERS SUNDAY BEFORE
MOVING OFF THE COAST EARLY NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL IBRING ABT THE PSBLTY OF SCT SHOWERS/TSTMS NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR DCZ001.
MD...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MDZ006-007-011-
013-014-016>018.
VA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR VAZ052>057.
WV...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE...KCS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1102 AM EDT FRI JUL 27 2012
.SYNOPSIS...
A SLOW MOVING UPPER LEVEL SYSTEM WILL CONTINUE THE RISK FOR
SHOWERS AND STORMS THROUGH SATURDAY. DRIER AND MORE COMFORTABLE
CONDITIONS WILL SETTLE IN BY THE END OF THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE DELAYED ONSET OF PRECIPITATION SLIGHTLY WITH 11AM UPDATE.
TIMING ALIGNS A BIT BETTER WITH 10Z HRRR AND 12Z NAM RUNS. SEVERE
POTENTIAL WILL BE AT LEAST PARTLY CONTINGENT ON WHAT HAPPENS WITH
CLOUD COVER DURING THE AFTERNOON. WITH MOSTLY CLOUDY SKIES
PERSISTING INTO THE LATE MORNING...THIS SHOULD REDUCE OVERALL
HEATING FOR THE DAY. HOWEVER...THIS CERTAINLY DOES NOT RULE OUT
POTENTIAL FOR SEVERE WEATHER...ESPECIALLY IN SPC SLIGHT RISK AREA
WHICH INCLUDES OHIO AND NORTHERN WV PANHANDLE COUNTIES. NO RELIEF
FOR MUGGY AIR...WITH DEWPOINTS REMAINING IN THE 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM NAM MODEL OUTPUT,
SHOWS HUMID AND HENCE UNSTABLE CONDITIONS REMAINING ACROSS THE
UPPER OHIO VALLEY UNTIL THE COLD FRONT, WITH LOWER DEW POINTS,
MOVES SOUTHWARD THROUGH AREA, SATURDAY NIGHT. THUS HAVE MAINTAINED
A CHANCE OF THUNDERSTORMS INTO SATURDAY EVENING.
HIGH PRESSURE SHOULD PROVIDE DRY CONDITIONS SUNDAY.
FORECASTED TEMPERATURES USING BLEND OF RECENT GFS AND NAM MOS AND
SREF MEAN VALUES, WHICH INDICATED TEMPERATURES CONTINUING WARMER
THAN NORMAL, WITH DAYTIME HIGHS BY UP TO 5 DEGREES, AND EARLY
MORNING LOWS BY UP TO 10 DEGREES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXPECT DRY CONDITIONS TO HOLD UNDER WEAK SURFACE HIGH PRESSURE
THROUGH MONDAY.
AN UPPER TROUGH IS PROGGED TO REMAIN OVER THE EAST COAST THROUGH
MUCH OF NEXT WEEK. MODELS CONTINUE TO HINT AT A SURFACE LOW MOVING
SLOWLY ALONG THE EAST COAST TUESDAY THROUGH THURSDAY...WHILE A
FRONTAL BOUNDARY APPROACHES FROM THE GREAT LAKES. PLAN TO KEEP
CHANCE POPS FOR SHOWERS AND THUNDERSTORMS TUESDAY INTO THURSDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
ISOLATED LOCATIONS REMAIN UNDER IFR CIGS LATE THIS MORNING...BUT
IMPROVEMENT TO VFR IS ANTICIPATED DURING THE AFTERNOON. SCT TO
NMRS SHRA/TSRA AND ASSOCIATED RESTRICTIONS ARE EXPECTED AS LOW
PRES MOVES ALONG FRONT THIS AFTN AND EVE. EXPECT GENL MVFR IN
SHRA AND IFR VSBY IN THE TSRA.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SCT TSRA/RESTRICTION POTENTIAL WL RMN THROUGH SATURDAY AS AN UPR
TROF AND A SECONDARY FRONT PUSH ACRS THE UPR OH VALLEY. DRY VFR
CONDITIONS ARE EXPECTED UNDER SFC HIGH PRES SUNDAY AND MONDAY.
INCRSG MOISTURE ASSOCIATED WITH AN EAST COAST LOW MAY FUEL SCT
SHRAS AND TSRA BY TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1055 AM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TODAY AND SLOWLY MOVE THROUGH
THE REGION TONIGHT. HIGH PRESSURE RETURNS SATURDAY AND REMAINS
INTO THE BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT CURRENTLY DRAPED FROM THE ERN GREAT LAKES ACROSS THE
PA/NY BORDER WILL SAG SOUTHEAST TOWARD THE CENTRAL MID ATLANTIC
TODAY. 12Z MODIFIED SOUNDING STILL SUPPORTS HIGH TEMPS IN THE MID
90S AT IAD...SO HIGH TEMP FORECAST FOR UPPER 90S IN DC/BALTIMORE
AREA STILL LOOKS VALID. TEMPS RUNNING A FEW DEGREES COOLER WEST OF
THE METRO AREAS DUE TO DEBRIS CLOUDS...BUT CLEARING TREND IS IN
PLACE LATE THIS MORNING.
SCATTERED SHOWERS HAVE DEVELOPED ALONG A PRE-FRONTAL TROUGH OVER
CENTRAL WV. 12Z NAM/09Z SREF SUPPORT THIS ACTIVITY BUILDING AND
MOVING EWD TOWARDS THE CWA THIS AFTN...BUT CLOUDS IN PLACE OVER WV
MAY LIMIT COVERAGE AND SEVERE THREAT. HRRR DOES NOT SUPPORT THIS
DEVELOPMENT...BUT INSTEAD FOCUSES CONVECTIVE INITIATION OVER THE
MOUNTAINS AND PIEDMONT EARLY THIS AFTERNOON. 12Z IAD SOUNDING
INDICATES SUFFICIENT SHEAR OVER THE REGION...AND IF SURFACE TEMPS
WARM AS FORECAST A 750MB CAP SHOULD BE BROKEN ALLOWING SB CAPE TO
REACH 2600 J/KG. SPC HAS A SLIGHT RISK OVER MOST OF VA AND MD EAST
OF THE BLUE RIDGE TODAY. MAIN THREAT WOULD BE DAMAGING
WINDS...ALTHOUGH A LARGE HAIL THREAT EXISTS AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
COLD FRONT SLOWLY SAG SOUTH TOWARD SERN VA WITH UPR TROUGH
REMAINING BACK OVER THE OH VLY. SHOULD SEE A BREAK IN PRECIP FOR
I-95 AND WEST /NOTE THE WEST/ BY THE EVENING...WITH PRECIP
PERSISTING EAST/SOUTH OF I-95 WELL INTO THE OVERNIGHT. MIN TEMPS MID
60S PIEDMONT AND WEST...LOW TO MID 70S I-95 AND EAST.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE ULTRA HIGH TEMPS WL BE HELD AT BAY DURG THE XTND PD. THIS IS
FREQUENTLY THE TIME OF YR WHEN THE "FOUR CORNERS HIGH" DVLPS OVR THE
SWRN U.S. ...AND THIS APPEARS TO BE THE CASE IN ALL OF THE XTND
MDLS. BECAUSE OF THIS THE ERN U.S. WL BE UNDER A SLT UPPER TROF.
THIS WL KEEP THE REALLY HOT WX...AND THE 70+ DWPTS...AT BAY FOR
THE FINAL DAYS OF JUL AND THE BEGINNING OF AUG. IN THE MID
ATLC...XPCT MOST OF THE XTND PD TO HV HIGH TEMPS IN THE MU80S.
LOWS RANGING FM THE L70S IN THE CITIES TO THE U50S IN THE
HIGHLANDS...BUT THE MAJORITY OF WL HV LOWS IN THE M60S.
THERE ISN`T MUCH TO HANG ONTO REGARDING POP CHCS. W/ ERN TROF IT
IS PSBL THAT A BNDRY COULD DVLP SOMETIME NEXT WK AND SERVE AS A
FOCUS FOR TSTM DVLPMNT...OTHERWISE SCT AFTN TSTMS IS THE BEST CHC
FOR RAFL.
ONE DAY CLOSER TO THE END OF THE MONTH...THIS RMNS THE WARMEST JUL
(AVG TEMP) IN DC ON RECORD. IT`S AMAZING THAT #2 AND 3 ARE THE PRVS
TWO YRS...EVEN THO RECORDS GO BACK TO 1871. BWI - THIS JUL IS IN
THE #2 SLOT...0.2 DEGS BEHIND 2010. THIS JUL IS ALSO #1 FOR
IAD...0.5 DEG AHD OF LAST YR.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR THIS MORNING. BRIEF LIGHT RAIN EXPECTED AT KMRB BEFORE 13Z.
THUNDERSTORMS/POTENTIAL PERIODS OF IFR CONDS THIS AFTERNOON AHEAD
OF A COLD FRONT. SWLY/WLY FLOW AROUND 10 KT TODAY. COLD FRONT
SLOWLY CROSSES TONIGHT WITH VFR CONDITIONS UNDER MID LEVEL CLOUDS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS SUNDAY BEFORE MOVING OFF
THE COAST FOR THE FIRST PART OF NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL INCREASE THE CHANCES FOR SHOWERS/TSTMS DURING THIS
TIME...HOWEVER NO WIDESPREAD SVR OUTBRK CAN BE SEEN ON THE
HORIZON.
&&
.MARINE...
WLY/SWLY FLOW AROUND 10 KT CONTINUE THROUGH TODAY. SCATTERED
THUNDERSTORMS EXPECTED LATE THIS AFTERNOON WELL INTO THE OVERNIGHT
WITH A DAMAGING WIND THREAT AHEAD/ALONG A SLOW MOVING COLD FRONT.
SURFACE HIGH PRESSURE WILL BUILD OVER THE WATERS SUNDAY BEFORE
MOVING OFF THE COAST EARLY NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL IBRING ABT THE PSBLTY OF SCT SHOWERS/TSTMS NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR DCZ001.
MD...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MDZ006-007-011-
013-014-016>018.
VA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR VAZ052>057.
WV...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE...KCS
AREA FORECAST DISCUSSION...CORRECTED
NWS DETROIT/PONTIAC MI
333 PM EDT FRI JUL 27 2012
.SHORT TERM...THIS EVENING AND OVERNIGHT
CONVECTION HAS ERUPTED THIS AFTERNOON IN ADVANCE OF A MID LEVEL
SHORT WAVE IMPULSE NOW ROTATING INTO WRN LOWER MI. THE REGIONAL
WATER VAPOR LOOP INDICATES SMALLER SCALE CIRCULATIONS EMBEDDED
WITHIN THE SHORT WAVE...ONE NEAR MUSKEGON AND ONE OVER NW LOWER MI.
THE MID LEVEL WAVE WILL TRACK ACROSS SE MI THIS EVENING. DESPITE THE
EARLY ONSET OF CONVECTION...THE LARGER SCALE ASCENT ASSOCIATED WITH
THIS WAVE AND AMPLE LOW LEVEL MOISTURE WILL SUSTAIN CONVECTION INTO
AT LEAST EARLY EVENING. THUS FAR...SOME OF THE STRONGER STORMS HAVE
BEEN PRODUCING HAIL...INTENSE RAINFALL AND FREQUENT LIGHTNING. MID
LEVEL DRY AIR SHOWN ON THE WATER VAPOR LOOP SHOULD CONTINUE TO
SUPPORT SOME HAIL IN THE STRONGER CELLS. SLOW STORM MOVEMENT AND
PROLONGED LARGER SCALE FORCING WILL ALSO CONTINUE THE THREAT OF
LOCALIZED HEAVY RAINFALL. LENAWEE AND MONROE COUNTIES HAVE BEEN
PLACED IN A SEVERE THUNDERSTORM WATCH AS THEY ARE CLOSER TO THE
POOL OF BETTER INSTABILITY ACROSS THE OHIO VALLEY. STEEPER LOW
LEVEL LAPSE RATES AND STRONGER MID LEVEL WINDS NEAR THE OHIO
BORDER WILL ALSO PROVIDE AN OPPORTUNITY FOR STRONGER STORMS IN
THIS REGION. THE LATEST NAM AND RUC CONTINUE TO SUGGEST SOME
ENHANCEMENT IN MID TROPOSPHERIC DEFORMATION ALONG AND NORTH OF THE
I-69 CORRIDOR THROUGH EARLY EVENING AS THE CIRCULATION NEAR MKG
PUSHES EAST. THIS FORCING IS EXPECTED TO LINGER PAST 00Z BEFORE
SLOWLY WEAKENING AS IT MOVES EAST OF PORT HURON SHORTLY AFTER
MIDNIGHT...SUPPORTING DECREASING POPS THROUGH THE COURSE OF THE
NIGHT.
WEAK SFC LOW PRESSURE NOW LOCATED OVER NW OHIO WILL PUSH SOUTH
DURING THE NIGHT. SOME RESIDUAL SFC TROUGHING WILL LINGER OVER SE MI
INTO THE OVERNIGHT. THIS ALONG WITH NORTHEAST FLOW OFF LAKE HURON
AND THE DEVELOPMENT OF A WEAK SHALLOW INVERSION SHOULD ALLOW SOME
STRATUS REDEVELOPMENT TONIGHT. DRY AIR IS HOWEVER EXPECTED TO
IMPINGE ON THE SAGINAW VALLEY TOWARD DAYBREAK...WHICH MAY LEAD TO
SOME CLEARING NORTH OF FLINT LATE. THE POTENTIAL CLOUD COVER AND
INCREASING NERLY GRADIENT SHOULD HOLD MIN TEMPS MAINLY IN THE 60S
/WITH SOME 50S POSSIBLE IN THE TRI CITIES WHERE CLEARING IS POSSIBLE
PRIOR TO DAYBREAK/.
&&
.LONG TERM...SATURDAY THROUGH NEXT FRIDAY
SATURDAY BEGINS WITH THE EXIT OF THE MID-LEVEL WAVE AND SURFACE
PRESSURE TENDENCIES INCREASING ON THE ORDER OF 2-4 MB PER 6 HOURS.
LIFTED INDICES WILL BE WELL POSITIVE AND ANY LINGERING MOISTURE
CONTENT NEAR THE DETROIT RIVER WILL QUICKLY BE SCOURED OUT BY THE
APPROACHING HIGH PRESSURE. MORNING RH VALUES WILL BE HIGH ENOUGH TO
ALLOW FOR PATCHY AM FOG...OTHERWISE AN IDEAL SUMMER WEEKEND IS
EXPECTED. MAX TEMPERATURES WILL BE NEAR CLIMO NORMS AS A LOW
AMPLITUDE/LONGWAVE TROUGH SETTLES OVER THE REGION. BY SUNDAY NIGHT,
THE SURFACE HIGH WILL BE PUSHED EAST BY AN APPROACHING 100KT JET AND
SURFACE LOW.
THE GREAT LAKES REGION WILL REMAIN UNDER THE INFLUENCE OF A STABLE
NORTHWESTERLY FLOW CONFIGURATION ALOFT FOR MUCH OF NEXT WEEK. THE
NWP SOLUTION SPACE DOES DIVERGE SOMEWHAT TOWARD MIDWEEK...WITH THE
27.00 ECMWF BEING A BIT MORE AGGRESSIVE WITH RELEASING A PORTION OF
THE LONGWAVE RIDGE THROUGH THE UPPER MISSISSIPPI VALLEY INTO THE
WESTERN LAKES REGION. REGARDLESS OF THE SOLUTION VARIANCE...THE NET
RESULT WILL BE SEASONABLE CONDITIONS /NEAR TO SLIGHTLY ABOVE AVERAGE
TEMPERATURES/ WITH AN OCCASIONAL SHOT AT MEASURABLE PRECIPITATION.
CONSENSUS TIMING OF EMBEDDED SHORTWAVES WOULD SUGGEST THE BEST
CHANCES FOR RAINFALL WILL BE TUESDAY AND THURSDAY...BUT THAT WILL
CERTAINLY REQUIRE GREATER REFINEMENT GIVEN THE POOR RESOLUTION OF
THESE TRANSIENT FEATURES.
&&
.MARINE...
NORTHEASTERLY WINDS WILL INCREASE THIS EVENING AS LOW PRESSURE SINKS
SOUTH ACROSS THE OHIO VALLEY AND HIGH PRESSURE BUILDS OVER THE
NORTHERN GREAT LAKES. THIS ALONG WITH RECENT OBSERVATIONS OVER LAKE
HURON /ESPECIALLY SAGINAW BAY/ SUGGEST THESE WINDS ARE GOING TO KICK
UP SOME FAIRLY GOOD WAVE HEIGHTS THIS EVENING...PROMPTING THE
ISSUANCE OF SMALL CRAFT ADVISORIES FOR SAGINAW BAY AND THE NEARSHORE
WATERS FROM PORT AUSTIN DOWN TO PORT HURON. WINDS WILL RELAX ON
FRIDAY AS THE HIGH NUDGES INTO LOWER MI.
&&
.AVIATION...ISSUED 103 PM EDT FRI JUL 27 2012
//DISCUSSION...
SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AND INTENSITY
DURING THE COURSE OF THE AFTERNOON AS AN UPPER SHORT WAVE APPROACHES
FROM THE WEST AND INTERACTS WITH DAYTIME DESTABILIZATION. THE MORE
PERSISTENT FORCING AND THUS MORE PROLONGED PERIOD OF CONVECTION IS
EXPECTED TO OCCUR AROUND FNT AND POSSIBLY MBS. WHILE THE LOW CLOUDS
HAVE BEEN SLOWLY RECEDING OVER THE LAST COUPLE OF HOURS...THE
INCREASE IN SHOWERS SHOULD ALLOW A TRANSITION BACK TOWARD MVFR
CEILING HEIGHTS TOWARD EVENING. LOW LEVEL MOISTURE IS EXPECTED TO
CONTINUE TO FILTER INTO SE MI THIS EVENING AS LOW PRESSURE NOW OVER
SRN LAKE MI DROPS INTO THE OHIO VALLEY. THIS WILL LIKELY SUSTAIN
SOME SEMBLANCE OF LOW CLOUDS AND POSSIBLE FOG INTO THE OVERNIGHT.
DRIER AIR NOW NOTED NORTH OF LAKE HURON SHOULD HOWEVER ADVECT INTO
THE AREA FROM THE NORTH OVERNIGHT...LEADING TO STEADY IMPROVEMENT IN
CONDITIONS TOWARD DAYBREAK SATURDAY.
FOR DTW...BASED ON THE RATE OF DESTABILIZATION AND TIMING OF THE
APPROACHING FORCING...THERE IS A GOOD CHANCE OF THUNDERSTORMS
DEVELOPING AROUND 19 OR 20Z AND CONTINUING INTO 23 OR 00Z.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FT THIS AFTERNOON AND
TONIGHT.
* MEDIUM CONFIDENCE IN THUNDERSTORMS THIS AFTERNOON AND EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
HURON INCLUDING SAGINAW BAY...UNTIL 6 AM SATURDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...SC
LONG TERM....MM
MARINE.......SC
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GAYLORD MI
120 PM EDT FRI JUL 27 2012
.SYNOPSIS...
ISSUED AT 409 AM EDT FRI JUL 27 2012
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY...
BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
WILL THEN PROVIDE PLEASANT WEATHER FOR THE WEEKEND...BUT MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN EARLY NEXT WORK
WEEK. NEAR SEASONAL TEMPERATURES ARE EXPECTED FOR THE NEXT SEVERAL
DAYS.
&&
.UPDATE...
ISSUED AT 120 PM EDT FRI JUL 27 2012
GOING FORECAST IN GOOD SHAPE THE REMAINDER OF THE AFTERNOON...WITH
RAIN HAVING A VERY HARD TIME MAKING MUCH NORTHWARD PROGRESS ON THE
FRINGES OF ELONGATING MID LEVEL DEFORMATION AXIS. HAVE ALREADY
SEEN SOME QUITE HEAVY TOTALS IN A FEW SPOTS (CADILLAC/FALMOUTH
COME TO MIND)...AND EFFICIENT WARM RAIN PROCESSES WILL CONTINUE IN
ANY SHOWERS/STORMS INTO LATE AFTERNOON. BEGINNING TO SEE A DIURNAL
COMPONENT TO ACTIVITY ACROSS SOUTHWEST COUNTIES WHERE SOME PEAKS
OF SUN ARRIVED EARLIER...AND SUSPECT THIS TREND WILL CONTINUE
ALONG THE M-55/WEST OF US-127 CORRIDOR THROUGH 22-23Z OR SO. ALL
THE WHILE...WILL CONTINUE TO SEE THINNING OF CLOUD COVER FOR
NORTHERN AREAS...WITH JUST SOME CU DEVELOPMENT. AS SUCH...EARLIER
TEMP FORECAST REMAINS INTACT...SHOWING LOW 70S AT BEST HIGHER
TERRAIN ON UPSLOPE FLOW TO MID/UPPER 70S FAR NORTH WITH BETTER SUN.
UPDATE ISSUED AT 1016 AM EDT FRI JUL 27 2012
GIST OF THE GOING FORECAST IS INTACT AS WE HEAD INTO THE
AFTERNOON...WITH ONLY MINOR TWEAKS MADE...PRIMARILY TO NORTHWARD
EXTENT OF EXPECTED PRECIP SHIELD. MODESTLY STRONG UPPER WAVE
CONTINUES TO PROGRESS THROUGH WISCONSIN...WITH A NOTABLE 700-500MB
AXIS OF DEFORMATION FORCING ACTING TO ELONGATE A BAND OF RAIN OVER
MUCH OF THE AREA SOUTH OF M-72. PRONOUNCED LOW LEVEL THETA-E AXIS
RUNNING ACROSS THIS AREA IS ALSO SERVING TO PROMOTE SOME WEAK
INSTABILITY BENEATH COOLING MID LEVELS...WITH UP TO 500 J/KG
MUCAPE PER SHORT TERM RAP FORECAST RAOBS. AS SUCH...NO SURPRISE WE
ARE SEEING OCCASIONAL THUNDER BREAK OUT AS WELL.
HEADING INTO THE LATE MORNING/AFTERNOON...SUSPECT PERIODS OF
SHOWERS AND STORMS WILL CROSS MUCH OF THE SOUTHERN HALF OF THE
CWA...ALL WHILE EXPANSIVE LOW LEVEL RIDGING AND ASSOCIATED DRYING
PUT A DEFINITELY NORTHERN EDGE TO THE PRECIP SHIELD. PER SHORT
TERM GUIDANCE AND STRONG SREF HINTS...WILL TRIM THE NORTHERN TIER
OF HIGHER POPS...WITH AREAS CLOSER TO LAKE HURON (NORTH OF M-32)
AND JUST ABOUT ALL OF EASTERN UPPER PROBABLY OUT OF THE MIX FOR
MUCH OF THE DAY. IN ADDITION TO EXPECTED AXIS OF DEFORMATION
FORCING...WILL LIKELY ALSO SEE SOME DIURNAL HELP TO THE PRECIP
WITHIN A QUITE MOIST AIRMASS...WITH SURFACE TEMPS INTO THE
LOWER/MIDDLE 70S PROMOTING MUCAPE VALUES UP TOWARD 700 J/KG. GIVEN
THE UPPER COLD POOL SKIRTING OVERHEAD AND A GOOD CHUNK OF
AVAILABLE INSTABILITY SITUATED ABOVE THE -12C ISOTHERM...SMALL
HAIL REMAINS A THREAT WITH ANY CONVECTION THAT DEVELOPS.
IN ADDITION...LOCALLY VERY HEAVY RAIN THREAT EXISTS WITHIN A
CORRIDOR OF 1.5+ INCH PWATS DOWN NEAR THE M-55 CORRIDOR WHERE
STEERING FLOW IS AN ANEMIC 5-10 KNOTS. MEANWHILE...FREEZING LEVELS
UP AROUND 10KFT AND A SATURATED ENVIRONMENT BELOW WILL SUPPORT VERY
EFFICIENT WARM RAIN PROCESSES...AND ENTIRELY POSSIBLE A FEW SPOTS
COULD PICK UP A LOCALIZED 2+ INCHES OF RAIN. CERTAINLY SOMETHING TO
WATCH. WILL ALSO HAVE TO WATCH VERY SMALL POTENTIAL FOR WATERSPOUTS
OVER LAKE MICHIGAN WITH UPPER COLD POOL SLIPPING OVERHEAD WHILE
WATER TEMPS ARE IN THE 22-24C RANGE. BEST THREAT WILL PROBABLY BE
OVER THE SOUTHERN HALF OF THE LAKE WHERE LOW LEVEL CONVERGENCE
BOUNDARY WILL RESIDE.
PER SATELLITE TRENDS...HAVE LOWERED GOING HIGHS A COUPLE OF
DEGREES INLAND WITH ONGOING UPSLOPE FLOW INTO THE HIGHER TERRAIN
LIKELY CAPPING THINGS AROUND 70 DEGREES...WITH DOWNSLOPE FLOW INTO
NORTHWEST LOWER KICKING THINGS TOWARD THE MID 70S. WARMEST SPOTS
WILL BE EASTERN UPPER WITH THINNING CLOUDS INTO THE AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 409 AM EDT FRI JUL 27 2012
EARLY MORNING SURFACE ANALYSIS SHOWS AN EAST-WEST ORIENTED TROUGH
AXIS LYING ACROSS SOUTHERN LOWER MICHIGAN/CENTRAL WISCONSIN.
COMPACT UPPER LOW WAS SPINNING SOUTHEAST INTO NORTHWEST
WISCONSIN...WITH A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ARCING
AROUND THIS CIRCULATION FROM THE MICHIGAN/WISCONSIN BORDER SOUTHWARD
ACROSS EASTERN WISCONSIN (WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD AHEAD OF THIS LOW SPREADING ACROSS LAKE MICHIGAN).
MEANWHILE...A FEW SPOTTY RADAR RETURNS DEVELOPED NORTH OF THE
SURFACE TROUGH AXIS SOUTH OF THE M-55 CORRIDOR WHERE LOW LEVEL LAPSE
RATES WERE LIKELY A LITTLE STEEPER PER 00Z DTX SOUNDING.
UPPER LEVEL FEATURE WILL CONTINUE TO TRACK SOUTHEAST AND CROSS
SOUTHERN LOWER MICHIGAN DURING THE DAY. WEAK RIDGE OF HIGH PRESSURE
WILL BUILD INTO NORTHERN MICHIGAN IN THE WAKE OF THIS SYSTEM TONIGHT.
TRACK OF THE UPPER LEVEL LOW SUGGESTS HIGHEST PRECIPITATION CHANCES
TODAY WILL BE ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
WILL BENEFIT THE MOST FROM THE SYNOPTIC COMPONENT WHICH SHOULD
ARRIVE THIS MORNING...PLUS STRONGEST DIURNAL COMPONENT WHERE LOW
LEVEL MOISTURE WILL BE MAXIMIZED AND MAY RESULT IN MLCAPE VALUES IN
THE 1000J/KG RANGE. PRECIPITATION CHANCES WILL BECOME MORE
SCATTERED TO THE NORTH WITH DRIER LOW LAYERS...AND LOOKING LIKE MOST
OF EASTERN UPPER WILL PROBABLY ESCAPE WITH LITTLE SIGNIFICANT
PRECIPITATION. THERMAL THROUGH ASSOCIATED WITH UPPER LEVEL WAVE
WILL LOWER FREEZING LEVELS...THUS STORMS WILL BE CAPABLE OF
PRODUCING HAIL. PLAN TO CARRY AN EXPLICIT MENTION OF SMALL HAIL
SOUTH OF A CVX-OSC LINE FROM LATE MORNING ONWARD. WARMEST HIGHS
TODAY WILL PROBABLY BE NORTH OF THE BRIDGE WHERE THERE WILL BE MORE
SUN ESPECIALLY LATER TODAY...IN GENERAL EXPECT HIGHS MAINLY IN THE
70S.
AS UPPER WAVE SLIPS INTO THE OHIO VALLEY THIS EVENING AND DRIER AIR
FILTERS INTO NORTHERN MICHIGAN IN ITS WAKE...THREAT FOR SHOWERS WILL
COME TO AN END ACROSS CENTRAL LOWER COUNTIES WITH SKIES CLEARING.
MAYBE A LITTLE PATCHY FOG ACROSS PARTS OF NORTHERN LOWER...BUT
SHOULD BE A SEASONABLY CHILLY NIGHT. COULD SEE A FEW SHELTERED
SPOTS DROPPING BELOW 50 EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM EDT FRI JUL 27 2012
CURRENT UPPER LEVEL PATTERN SET TO CHANGE LITTLE FOR THE FORESEEABLE
FUTURE...FEATURING INTERMOUNTAIN WEST/HIGH PLAINS RIDGING BOOKENDED BY
EASTERN NOAM AND FAR EAST PACIFIC TROUGHINESS. AS A RESULT...
RECENTLY ESTABLISHED NORTHWEST FLAVOR TO MID LEVEL FLOW OVER THE
LAKES WILL REMAIN REMARKABLY PERSISTENT...KEEPING TEMPERATURES
LOCKED IN TO NEAR NORMAL LEVELS AND ALLOWING PERIODIC RAIN CHANCES
AS OCCASIONAL DISTURBANCES ROTATE THROUGH THE REGION. FORECAST
CONCERNS RELEGATED TO THE LATTER OF THESE TWO...FOCUSING ON SHOWER
AND STORM CHANCES NEXT WORK WEEK.
RESERVOIR OF DRY CANADIAN AIR SWEEPS SOUTH INTO THE NORTHERN LAKES
BEHIND TOMORROWS DEPARTING SYSTEM...SETTING UP A MAINLY QUIET...DRY
WEEKEND. OVERHEAD HIGH PRESSURE EXPECTED TO LEAD TO EXCELLENT LAKE
BREEZE DEVELOPMENT SATURDAY...AND COMBINED WITH LINGERING 850MB
THERMAL TROUGH...SHOULD SET UP A PRETTY DECENT INLAND CU FIELD BY
AFTERNOON. FORMIDABLE MID LEVEL CAP EXPECTED TO KEEP CLOUD HEIGHTS
IN CHECK AND PREVENT ANY SHOWER DEVELOPMENT. LATEST PROGS STARTING
TO THROW SOME CONCERN INTO INHERITED DRY SUNDAY... ESPECIALLY ACROSS
EASTERN UPPER. SUBTLE MID LEVEL WAVE AND BEGINNINGS OF MODEST RETURN
FLOW NOW SUPPORTING SOME EASTERN UPPER SHOWERS BY AFTERNOON.
GUIDANCE IS NOTORIOUS FOR BRINGING IN MOISTURE TOO QUICKLY...
ESPECIALLY WITH AN ANTECEDENT RELATIVELY DRY AIR MASS. WILL REFRAIN
FROM INTRODUCING ANOTHER PERIOD OF LOW END SHOWER POTENTIAL (SEE
BELOW)...WAITING FOR MORE CONSISTENCY BEFORE DOING SO. NEAR SEASONAL
HIGH TEMPERATURES EXPECTED BOTH AFTERNOONS...WITH READINGS IN THE
UPPER 70S AND LOWER 80S.
"POTENTIALLY" SOMEWHAT MORE ACTIVE PERIOD OF WEATHER RETURNS NEXT
WORK WEEK...WITH ABOVE OUTLINED FLOW AT LEAST OPENING UP THE
OPPORTUNITY FOR A FEW DISTURBANCES TO ROTATE THROUGH THE REGION.
NOTHING EARTH SHATTERING PER TRENDS...WITH GUIDANCE SUGGESTING LOW
AMPLITUDE WAVES AND DEEPEST CORE OF MOISTURE TO REMAIN WELL TO OUR
SOUTHWEST. AS EXPECTED WITH THIS FLOW REGIME...EXACT TIMING REMAINS
PROBLEMATIC AT BEST...WITH THE ECMWF LAGGING BEHIND BOTH THE GFS AND
GEM BY SEVERAL HOURS WITH LEAD WAVE LATE SUNDAY NIGHT INTO MONDAY.
SIMPLY NOT PRUDENT AT THIS HOUR TO PICK ONE OVER THE OTHER...AND
WILL RIDE WITH LATE SUNDAY NIGHT INTO MONDAY LOW END RAIN CHANCES.
SAME GOES FOR MONDAY NIGHT AND TUESDAY AS ADDITIONAL SUPPORT
PINWHEELS OVER THE REGION. UNFORTUNATELY...BECAUSE OF SAID TIMING
CONCERNS...SIMPLY NO WAY TO SIDESTEP INHERITED MULTI-PERIOD RAIN
CHANCES...ALTHOUGH IN ALL LIKELIHOOD...MUCH OF THE TIME OUTLINED
ABOVE WILL REMAIN DRY. OF COURSE...TEMPERATURES DIRECTLY TIED TO
CONVECTIVE TRENDS...BUT OFF THE DECK THERMAL TRENDS SUGGEST HIGHS
BOTH MONDAY AND TUESDAY REMAINING IN THE UPPER 70S AND LOWER 80S.
PATTERN LOOKS TO SIMPLY REPEAT ITSELF LATER IN THE WEEK...WITH
TRENDS SUPPORTING A DRY MID WEEK PERIOD FOLLOWED BY ADDITIONAL RAIN
CHANCES THURSDAY INTO FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 120 PM EDT FRI JUL 27 2012
TALE OF TWO DIFFERENT WEATHER REGIMES ACROSS THE TAF SITES AS AN
UPPER LOW CONTINUES TO TRAVERSE THE REGION. WORST CONDITIONS BY
FAR WILL COME AT MBL AND TVC WITH MVFR TO PERIODIC IFR CONDITIONS
WITH OCCASIONAL ROUNDS OF SHOWERS AND PERHAPS A THUNDERSTORM.
FARTHER NORTH FOR PLN/APN...SLOW IMPROVEMENT IS EXPECTED AS LOWER
CLOUDS LIFT INTO A VFR DECK THROUGH THE AFTERNOON. CONDITIONS AT
ALL SITES WILL IMPROVE OVERNIGHT AS THE UPPER LOW DEPARTS AND HIGH
PRESSURE BEGINS TO BUILD INTO THE AREA. INFLUX OF DRIER AIR SHOULD
PREVENT ANY WIDESPREAD FOG FROM DEVELOPING AT APN/PLN...WITH A
BETTER CHANCE AT TVC AND ESPECIALLY MBL WHERE RAINS HAVE FALLEN OR
WILL FALL TODAY. WINDS FROM THE EAST AT UP TO 10 KNOTS WILL
DIMINISH OVERNIGHT...COMING FROM THE NORTH AT UP TO 8 KNOTS
SATURDAY WITH SOME AFTERNOON CUMULUS LIKELY TO DEVELOP.
&&
.MARINE...
ISSUED AT 409 AM EDT FRI JUL 27 2012
EAST/NORTHEAST WINDS EXPECTED TODAY ACROSS THE UPPER LAKES...WITH
THE FORECAST AREA SANDWICHED BETWEEN A TROUGH OF LOW PRESSURE
DROPPING SOUTH TOWARD THE OHIO VALLEY AND A WEAK RIDGE OF HIGH
PRESSURE BUILDING IN FROM THE NORTH. WINDS WILL BACK MORE TOWARD
THE NORTH TONIGHT BUT GRADIENT WILL BE WEAKENING AS AFOREMENTIONED
RIDGE BUILDS IN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...LAWRENCE
MARINE...JPB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
103 PM EDT FRI JUL 27 2012
.AVIATION...
//DISCUSSION...
SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AND INTENSITY
DURING THE COURSE OF THE AFTERNOON AS AN UPPER SHORT WAVE APPROACHES
FROM THE WEST AND INTERACTS WITH DAYTIME DESTABILIZATION. THE MORE
PERSISTENT FORCING AND THUS MORE PROLONGED PERIOD OF CONVECTION IS
EXPECTED TO OCCUR AROUND FNT AND POSSIBLY MBS. WHILE THE LOW CLOUDS
HAVE BEEN SLOWLY RECEDING OVER THE LAST COUPLE OF HOURS...THE
INCREASE IN SHOWERS SHOULD ALLOW A TRANSITION BACK TOWARD MVFR
CEILING HEIGHTS TOWARD EVENING. LOW LEVEL MOISTURE IS EXPECTED TO
CONTINUE TO FILTER INTO SE MI THIS EVENING AS LOW PRESSURE NOW OVER
SRN LAKE MI DROPS INTO THE OHIO VALLEY. THIS WILL LIKELY SUSTAIN
SOME SEMBLANCE OF LOW CLOUDS AND POSSIBLE FOG INTO THE OVERNIGHT.
DRIER AIR NOW NOTED NORTH OF LAKE HURON SHOULD HOWEVER ADVECT INTO
THE AREA FROM THE NORTH OVERNIGHT...LEADING TO STEADY IMPROVEMENT IN
CONDITIONS TOWARD DAYBREAK SATURDAY.
FOR DTW...BASED ON THE RATE OF DESTABILIZATION AND TIMING OF THE
APPROACHING FORCING...THERE IS A GOOD CHANCE OF THUNDERSTORMS
DEVELOPING AROUND 19 OR 20Z AND CONTINUING INTO 23 OR 00Z.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FT THIS AFTERNOON AND
TONIGHT.
* MEDIUM CONFIDENCE IN THUNDERSTORMS THIS AFTERNOON AND EVENING.
&&
.PREV DISCUSSION...ISSUED 1041 AM EDT FRI JUL 27 2012
UPDATE...
THE REGIONAL WATER VAPOR LOOP SHOWS A FAIRLY HEALTHY MID LEVEL
WAVE OVER ERN WISCONSIN. ALTHOUGH THIS WAVE IS EXPECTED TO DAMPEN
AS IT TRACKS ACROSS LOWER MI LATER TODAY...THERE WILL STILL BE
ADEQUATE FORCING FOR LARGE SCALE ASCENT DURING PEAK DAYTIME
HEATING. RECENT TRENDS IN THE VISIBLE LOOP ARE SHOWING SOME OF THE
LOW STRATUS STARTING TO TRANSITION TO A BROKEN CU FIELD AS DAYTIME
INSOLATION IS NOW WARMING THE BOUNDARY LAYER. THIS WILL SUPPORT
INCREASING CONVECTIVE CLOUD DEPTHS WHICH WILL LEAD TO OCCASIONAL
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. REGIONAL RADAR IMAGERY
IS SHOWING AN AREA OF MORE PERSISTENT RAIN AND EMBEDDED
THUNDERSTORMS EXTENDING FROM CNTL LOWER MI TO NW LOWER MI...WITHIN
A REGION OF WEAK MID LEVEL DEFORMATION...WHICH WILL TARGET THE
SAGINAW VALLEY AND THUMB THIS AFTERNOON AND EVENING. DEEP LAYER
MOISTURE WILL ALSO BE BETTER TO THE NORTH. GIVEN THE SLOW MOVEMENT
OF THE UPPER WAVE...SOME PROLONGED PERIODS OF MODERATE TO HEAVY
RAINFALL LOOK POSSIBLE ACROSS THE NORTHERN PORTIONS OF THE
FORECAST AREA.
DRY AIR IN THE MID LEVELS FARTHER SOUTH SUGGEST SOME AFTERNOON
STORMS MAY SUPPORT SOME SMALL HAIL. THERE HAS BEEN MORE PERSISTENT
SUNSHINE ACROSS LENAWEE AND MONROE COUNTIES THIS MORNING...WHICH
MAY ALLOW SOME BETTER INSTABILITY TO DEVELOP BY AFTERNOON /SB CAPE
UP TO 2000 J/KG/. THIS REGION WILL ALSO LIE ALONG THE NORTHERN
EDGE OF A 40KT MID LEVEL JET...SUPPORTIVE OF A SLIGHT CHANCE OF
STRONG TO POSSIBLE SEVERE STORMS LATER TODAY.
THE UPDATE WILL BE ISSUED MAINLY TO NUDGE POPS UPWARD.
PREV DISCUSSION...ISSUED 339 AM EDT FRI JUL 27 2012
SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1041 AM EDT FRI JUL 27 2012
.UPDATE...
THE REGIONAL WATER VAPOR LOOP SHOWS A FAIRLY HEALTHY MID LEVEL
WAVE OVER ERN WISCONSIN. ALTHOUGH THIS WAVE IS EXPECTED TO DAMPEN
AS IT TRACKS ACROSS LOWER MI LATER TODAY...THERE WILL STILL BE
ADEQUATE FORCING FOR LARGE SCALE ASCENT DURING PEAK DAYTIME
HEATING. RECENT TRENDS IN THE VISIBLE LOOP ARE SHOWING SOME OF THE
LOW STRATUS STARTING TO TRANSITION TO A BROKEN CU FIELD AS DAYTIME
INSOLATION IS NOW WARMING THE BOUNDARY LAYER. THIS WILL SUPPORT
INCREASING CONVECTIVE CLOUD DEPTHS WHICH WILL LEAD TO OCCASIONAL
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. REGIONAL RADAR IMAGERY
IS SHOWING AN AREA OF MORE PERSISTENT RAIN AND EMBEDDED
THUNDERSTORMS EXTENDING FROM CNTL LOWER MI TO NW LOWER MI...WITHIN
A REGION OF WEAK MID LEVEL DEFORMATION...WHICH WILL TARGET THE
SAGINAW VALLEY AND THUMB THIS AFTERNOON AND EVENING. DEEP LAYER
MOISTURE WILL ALSO BE BETTER TO THE NORTH. GIVEN THE SLOW MOVEMENT
OF THE UPPER WAVE...SOME PROLONGED PERIODS OF MODERATE TO HEAVY
RAINFALL LOOK POSSIBLE ACROSS THE NORTHERN PORTIONS OF THE
FORECAST AREA.
DRY AIR IN THE MID LEVELS FARTHER SOUTH SUGGEST SOME AFTERNOON
STORMS MAY SUPPORT SOME SMALL HAIL. THERE HAS BEEN MORE PERSISTENT
SUNSHINE ACROSS LENAWEE AND MONROE COUNTIES THIS MORNING...WHICH
MAY ALLOW SOME BETTER INSTABILITY TO DEVELOP BY AFTERNOON /SB CAPE
UP TO 2000 J/KG/. THIS REGION WILL ALSO LIE ALONG THE NORTHERN
EDGE OF A 40KT MID LEVEL JET...SUPPORTIVE OF A SLIGHT CHANCE OF
STRONG TO POSSIBLE SEVERE STORMS LATER TODAY.
THE UPDATE WILL BE ISSUED MAINLY TO NUDGE POPS UPWARD.
&&
.AVIATION...ISSUED 647 AM EDT FRI JUL 27 2012
//DISCUSSION...
NE FLOW OFF LAKE HURON HAS HELPED KEEP SURFACE MOISTURE ELEVATED
THUS HAS PRODUCED WIDESPREAD STRATUS. BETWEEN THE LOW STRATUS AND
LINGERING PATCHY FOG...MVFR CONDITIONS COULD CONTINUE FOR A COUPLE
MORE HOURS BEFORE LIFTING BACK TO VFR FOR THE AFTERNOON. THE STRATUS
HAS DONE A GOOD JOB KEEPING MOST OF THE FOG CONTAINED OVER SW LOWER
MI WITH HINTS OF IT APPROACHING FNT AND PTK AT TIMES. SURFACE LOW
PRESSURE SYSTEM APPROACHING LAKE MICHIGAN WILL REACH SE MI THIS
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS HAVE ALREADY STARTED
POPPING UP THIS MORNING BUT COVERAGE WILL INCREASE INTO THE
AFTERNOON AS DIURNAL HEATING AIDES IN THE DEVELOPMENT OF
PRECIPITATION. THIS MORNINGS COVERAGE WILL BE TOO ISOLATED TO
INCLUDE IN THE TAFS AT THIS TIME. HAVE CONTINUED THE MENTION OF
SHOWERS AFTER 18Z SINCE COVERAGE SHOULD BE MORE WIDESPREAD DURING
THAT TIME. WILL HOLD OFF ON MENTIONING THUNDER UNTIL WE CAN GET
BETTER TIMING OF THE STRONGER STORMS.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET AT LEAST
INTERMITTENTLY ON FRIDAY...BUT LOW CONFIDENCE ON TIMING.
* MEDIUM CONFIDENCE IN THUNDERSTORM DEVELOPMENT ON FRIDAY...BUT LOW
CONFIDENCE IN TIMING AND LOCATION.
&&
.PREV DISCUSSION...ISSUED 339 AM EDT FRI JUL 27 2012
SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SC
AVIATION.....DG
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1016 AM EDT FRI JUL 27 2012
.SYNOPSIS...
ISSUED AT 409 AM EDT FRI JUL 27 2012
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY...
BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
WILL THEN PROVIDE PLEASANT WEATHER FOR THE WEEKEND...BUT MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN EARLY NEXT WORK
WEEK. NEAR SEASONAL TEMPERATURES ARE EXPECTED FOR THE NEXT SEVERAL
DAYS.
&&
.UPDATE...
ISSUED AT 1016 AM EDT FRI JUL 27 2012
GIST OF THE GOING FORECAST IS INTACT AS WE HEAD INTO THE
AFTERNOON...WITH ONLY MINOR TWEAKS MADE...PRIMARILY TO NORTHWARD
EXTENT OF EXPECTED PRECIP SHIELD. MODESTLY STRONG UPPER WAVE
CONTINUES TO PROGRESS THROUGH WISCONSIN...WITH A NOTABLE 700-500MB
AXIS OF DEFORMATION FORCING ACTING TO ELONGATE A BAND OF RAIN OVER
MUCH OF THE AREA SOUTH OF M-72. PRONOUNCED LOW LEVEL THETA-E AXIS
RUNNING ACROSS THIS AREA IS ALSO SERVING TO PROMOTE SOME WEAK
INSTABILITY BENEATH COOLING MID LEVELS...WITH UP TO 500 J/KG
MUCAPE PER SHORT TERM RAP FORECAST RAOBS. AS SUCH...NO SURPRISE WE
ARE SEEING OCCASIONAL THUNDER BREAK OUT AS WELL.
HEADING INTO THE LATE MORNING/AFTERNOON...SUSPECT PERIODS OF
SHOWERS AND STORMS WILL CROSS MUCH OF THE SOUTHERN HALF OF THE
CWA...ALL WHILE EXPANSIVE LOW LEVEL RIDGING AND ASSOCIATED DRYING
PUT A DEFINITELY NORTHERN EDGE TO THE PRECIP SHIELD. PER SHORT
TERM GUIDANCE AND STRONG SREF HINTS...WILL TRIM THE NORTHERN TIER
OF HIGHER POPS...WITH AREAS CLOSER TO LAKE HURON (NORTH OF M-32)
AND JUST ABOUT ALL OF EASTERN UPPER PROBABLY OUT OF THE MIX FOR
MUCH OF THE DAY. IN ADDITION TO EXPECTED AXIS OF DEFORMATION
FORCING...WILL LIKELY ALSO SEE SOME DIURNAL HELP TO THE PRECIP
WITHIN A QUITE MOIST AIRMASS...WITH SURFACE TEMPS INTO THE
LOWER/MIDDLE 70S PROMOTING MUCAPE VALUES UP TOWARD 700 J/KG. GIVEN
THE UPPER COLD POOL SKIRTING OVERHEAD AND A GOOD CHUNK OF
AVAILABLE INSTABILITY SITUATED ABOVE THE -12C ISOTHERM...SMALL
HAIL REMAINS A THREAT WITH ANY CONVECTION THAT DEVELOPS.
IN ADDITION...LOCALLY VERY HEAVY RAIN THREAT EXISTS WITHIN A
CORRIDOR OF 1.5+ INCH PWATS DOWN NEAR THE M-55 CORRIDOR WHERE
STEERING FLOW IS AN ANEMIC 5-10 KNOTS. MEANWHILE...FREEZING LEVELS
UP AROUND 10KFT AND A SATURATED ENVIRONMENT BELOW WILL SUPPORT VERY
EFFICIENT WARM RAIN PROCESSES...AND ENTIRELY POSSIBLE A FEW SPOTS
COULD PICK UP A LOCALIZED 2+ INCHES OF RAIN. CERTAINLY SOMETHING TO
WATCH. WILL ALSO HAVE TO WATCH VERY SMALL POTENTIAL FOR WATERSPOUTS
OVER LAKE MICHIGAN WITH UPPER COLD POOL SLIPPING OVERHEAD WHILE
WATER TEMPS ARE IN THE 22-24C RANGE. BEST THREAT WILL PROBABLY BE
OVER THE SOUTHERN HALF OF THE LAKE WHERE LOW LEVEL CONVERGENCE
BOUNDARY WILL RESIDE.
PER SATELLITE TRENDS...HAVE LOWERED GOING HIGHS A COUPLE OF
DEGREES INLAND WITH ONGOING UPSLOPE FLOW INTO THE HIGHER TERRAIN
LIKELY CAPPING THINGS AROUND 70 DEGREES...WITH DOWNSLOPE FLOW INTO
NORTHWEST LOWER KICKING THINGS TOWARD THE MID 70S. WARMEST SPOTS
WILL BE EASTERN UPPER WITH THINNING CLOUDS INTO THE AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 409 AM EDT FRI JUL 27 2012
EARLY MORNING SURFACE ANALYSIS SHOWS AN EAST-WEST ORIENTED TROUGH
AXIS LYING ACROSS SOUTHERN LOWER MICHIGAN/CENTRAL WISCONSIN.
COMPACT UPPER LOW WAS SPINNING SOUTHEAST INTO NORTHWEST
WISCONSIN...WITH A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ARCING
AROUND THIS CIRCULATION FROM THE MICHIGAN/WISCONSIN BORDER SOUTHWARD
ACROSS EASTERN WISCONSIN (WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD AHEAD OF THIS LOW SPREADING ACROSS LAKE MICHIGAN).
MEANWHILE...A FEW SPOTTY RADAR RETURNS DEVELOPED NORTH OF THE
SURFACE TROUGH AXIS SOUTH OF THE M-55 CORRIDOR WHERE LOW LEVEL LAPSE
RATES WERE LIKELY A LITTLE STEEPER PER 00Z DTX SOUNDING.
UPPER LEVEL FEATURE WILL CONTINUE TO TRACK SOUTHEAST AND CROSS
SOUTHERN LOWER MICHIGAN DURING THE DAY. WEAK RIDGE OF HIGH PRESSURE
WILL BUILD INTO NORTHERN MICHIGAN IN THE WAKE OF THIS SYSTEM TONIGHT.
TRACK OF THE UPPER LEVEL LOW SUGGESTS HIGHEST PRECIPITATION CHANCES
TODAY WILL BE ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
WILL BENEFIT THE MOST FROM THE SYNOPTIC COMPONENT WHICH SHOULD
ARRIVE THIS MORNING...PLUS STRONGEST DIURNAL COMPONENT WHERE LOW
LEVEL MOISTURE WILL BE MAXIMIZED AND MAY RESULT IN MLCAPE VALUES IN
THE 1000J/KG RANGE. PRECIPITATION CHANCES WILL BECOME MORE
SCATTERED TO THE NORTH WITH DRIER LOW LAYERS...AND LOOKING LIKE MOST
OF EASTERN UPPER WILL PROBABLY ESCAPE WITH LITTLE SIGNIFICANT
PRECIPITATION. THERMAL THROUGH ASSOCIATED WITH UPPER LEVEL WAVE
WILL LOWER FREEZING LEVELS...THUS STORMS WILL BE CAPABLE OF
PRODUCING HAIL. PLAN TO CARRY AN EXPLICIT MENTION OF SMALL HAIL
SOUTH OF A CVX-OSC LINE FROM LATE MORNING ONWARD. WARMEST HIGHS
TODAY WILL PROBABLY BE NORTH OF THE BRIDGE WHERE THERE WILL BE MORE
SUN ESPECIALLY LATER TODAY...IN GENERAL EXPECT HIGHS MAINLY IN THE
70S.
AS UPPER WAVE SLIPS INTO THE OHIO VALLEY THIS EVENING AND DRIER AIR
FILTERS INTO NORTHERN MICHIGAN IN ITS WAKE...THREAT FOR SHOWERS WILL
COME TO AN END ACROSS CENTRAL LOWER COUNTIES WITH SKIES CLEARING.
MAYBE A LITTLE PATCHY FOG ACROSS PARTS OF NORTHERN LOWER...BUT
SHOULD BE A SEASONABLY CHILLY NIGHT. COULD SEE A FEW SHELTERED
SPOTS DROPPING BELOW 50 EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM EDT FRI JUL 27 2012
CURRENT UPPER LEVEL PATTERN SET TO CHANGE LITTLE FOR THE FORESEEABLE
FUTURE...FEATURING INTERMOUNTAIN WEST/HIGH PLAINS RIDGING BOOKENDED BY
EASTERN NOAM AND FAR EAST PACIFIC TROUGHINESS. AS A RESULT...
RECENTLY ESTABLISHED NORTHWEST FLAVOR TO MID LEVEL FLOW OVER THE
LAKES WILL REMAIN REMARKABLY PERSISTENT...KEEPING TEMPERATURES
LOCKED IN TO NEAR NORMAL LEVELS AND ALLOWING PERIODIC RAIN CHANCES
AS OCCASIONAL DISTURBANCES ROTATE THROUGH THE REGION. FORECAST
CONCERNS RELEGATED TO THE LATTER OF THESE TWO...FOCUSING ON SHOWER
AND STORM CHANCES NEXT WORK WEEK.
RESERVOIR OF DRY CANADIAN AIR SWEEPS SOUTH INTO THE NORTHERN LAKES
BEHIND TOMORROWS DEPARTING SYSTEM...SETTING UP A MAINLY QUIET...DRY
WEEKEND. OVERHEAD HIGH PRESSURE EXPECTED TO LEAD TO EXCELLENT LAKE
BREEZE DEVELOPMENT SATURDAY...AND COMBINED WITH LINGERING 850MB
THERMAL TROUGH...SHOULD SET UP A PRETTY DECENT INLAND CU FIELD BY
AFTERNOON. FORMIDABLE MID LEVEL CAP EXPECTED TO KEEP CLOUD HEIGHTS
IN CHECK AND PREVENT ANY SHOWER DEVELOPMENT. LATEST PROGS STARTING
TO THROW SOME CONCERN INTO INHERITED DRY SUNDAY... ESPECIALLY ACROSS
EASTERN UPPER. SUBTLE MID LEVEL WAVE AND BEGINNINGS OF MODEST RETURN
FLOW NOW SUPPORTING SOME EASTERN UPPER SHOWERS BY AFTERNOON.
GUIDANCE IS NOTORIOUS FOR BRINGING IN MOISTURE TOO QUICKLY...
ESPECIALLY WITH AN ANTECEDENT RELATIVELY DRY AIR MASS. WILL REFRAIN
FROM INTRODUCING ANOTHER PERIOD OF LOW END SHOWER POTENTIAL (SEE
BELOW)...WAITING FOR MORE CONSISTENCY BEFORE DOING SO. NEAR SEASONAL
HIGH TEMPERATURES EXPECTED BOTH AFTERNOONS...WITH READINGS IN THE
UPPER 70S AND LOWER 80S.
"POTENTIALLY" SOMEWHAT MORE ACTIVE PERIOD OF WEATHER RETURNS NEXT
WORK WEEK...WITH ABOVE OUTLINED FLOW AT LEAST OPENING UP THE
OPPORTUNITY FOR A FEW DISTURBANCES TO ROTATE THROUGH THE REGION.
NOTHING EARTH SHATTERING PER TRENDS...WITH GUIDANCE SUGGESTING LOW
AMPLITUDE WAVES AND DEEPEST CORE OF MOISTURE TO REMAIN WELL TO OUR
SOUTHWEST. AS EXPECTED WITH THIS FLOW REGIME...EXACT TIMING REMAINS
PROBLEMATIC AT BEST...WITH THE ECMWF LAGGING BEHIND BOTH THE GFS AND
GEM BY SEVERAL HOURS WITH LEAD WAVE LATE SUNDAY NIGHT INTO MONDAY.
SIMPLY NOT PRUDENT AT THIS HOUR TO PICK ONE OVER THE OTHER...AND
WILL RIDE WITH LATE SUNDAY NIGHT INTO MONDAY LOW END RAIN CHANCES.
SAME GOES FOR MONDAY NIGHT AND TUESDAY AS ADDITIONAL SUPPORT
PINWHEELS OVER THE REGION. UNFORTUNATELY...BECAUSE OF SAID TIMING
CONCERNS...SIMPLY NO WAY TO SIDESTEP INHERITED MULTI-PERIOD RAIN
CHANCES...ALTHOUGH IN ALL LIKELIHOOD...MUCH OF THE TIME OUTLINED
ABOVE WILL REMAIN DRY. OF COURSE...TEMPERATURES DIRECTLY TIED TO
CONVECTIVE TRENDS...BUT OFF THE DECK THERMAL TRENDS SUGGEST HIGHS
BOTH MONDAY AND TUESDAY REMAINING IN THE UPPER 70S AND LOWER 80S.
PATTERN LOOKS TO SIMPLY REPEAT ITSELF LATER IN THE WEEK...WITH
TRENDS SUPPORTING A DRY MID WEEK PERIOD FOLLOWED BY ADDITIONAL RAIN
CHANCES THURSDAY INTO FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 132 AM EDT FRI JUL 27 2012
COMPLEX AND CHALLENGING CLOUD FORECAST THROUGH FIRST HALF OF TAF
PERIOD. AREAS OF MVFR FOG/LOWER CLOUDS OVERNIGHT...WITH INCREASING
CHANCES OF SHOWERS TOWARD 12Z AS UPPER LOW OVER WESTERN SUPERIOR
APPROACHES THE AREA. LOCALIZED IFR VSBY/S POSSIBLE DUE TO FOG
BEFORE THE SHOWERS ARRIVE. CIGS GENERALLY MVFR FOR THE FIRST HALF
OF FRIDAY WITH SCATTERED SHOWERS AND A FEW THUNDERSTORMS. CIGS
STEADILY IMPROVING BY LATER FRIDAY AFTERNOON AS UPPER LOW DEPARTS
AND DRIER AIR BEGINS TO MOVE IN FROM THE NORTHWEST.
WINDS LESS THAN 10 KNOTS THROUGHOUT THE NEXT 24 HOURS.
&&
.MARINE...
ISSUED AT 409 AM EDT FRI JUL 27 2012
EAST/NORTHEAST WINDS EXPECTED TODAY ACROSS THE UPPER LAKES...WITH
THE FORECAST AREA SANDWICHED BETWEEN A TROUGH OF LOW PRESSURE
DROPPING SOUTH TOWARD THE OHIO VALLEY AND A WEAK RIDGE OF HIGH
PRESSURE BUILDING IN FROM THE NORTH. WINDS WILL BACK MORE TOWARD
THE NORTH TONIGHT BUT GRADIENT WILL BE WEAKENING AS AFOREMENTIONED
RIDGE BUILDS IN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...JK
MARINE...JPB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1007 AM EDT FRI JUL 27 2012
.SYNOPSIS...
ISSUED AT 409 AM EDT FRI JUL 27 2012
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY...
BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
WILL THEN PROVIDE PLEASANT WEATHER FOR THE WEEKEND...BUT MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN EARLY NEXT WORK
WEEK. NEAR SEASONAL TEMPERATURES ARE EXPECTED FOR THE NEXT SEVERAL
DAYS.
&&
.UPDATE...
ISSUED AT 1007 AM EDT FRI JUL 27 2012
GIST OF THE GOING FORECAST IS INTACT AS WE HEAD INTO THE
AFTERNOON...WITH ONLY MINOR TWEAKS MADE...PRIMARILY TO NORTHWARD
EXTENT OF EXPECTED PRECIP SHIELD. MODESTLY STRONG UPPER WAVE
CONTINUES TO PROGRESS THROUGH WISCONSIN...WITH A NOTABLE 700-500MB
AXIS OF DEFORMATION FORCING ACTING TO ELONGATE A BAND OF RAIN OVER
MUCH OF THE AREA SOUTH OF M-72. PRONOUNCED LOW LEVEL THETA-E AXIS
RUNNING ACROSS THIS AREA IS ALSO SERVING TO PROMOTE SOME WEAK
INSTABILITY BENEATH COOLING MID LEVELS...WITH UP TO 500 J/KG
MUCAPE PER SHORT TERM RAP FORECAST RAOBS. AS SUCH...NO SURPRISE WE
ARE SEEING OCCASIONAL THUNDER BREAK OUT AS WELL.
HEADING INTO THE LATE MORNING/AFTERNOON...SUSPECT PERIODS OF
SHOWERS AND STORMS WILL CROSS MUCH OF THE SOUTHERN HALF OF THE
CWA...ALL WHILE EXPANSIVE LOW LEVEL RIDGING AND ASSOCIATED DRYING
PUT A DEFINITELY NORTHERN EDGE TO THE PRECIP SHIELD. PER SHORT
TERM GUIDANCE AND STRONG SREF HINTS...WILL TRIM THE NORTHERN TIER
OF HIGHER POPS...WITH AREAS CLOSER TO LAKE HURON (NORTH OF M-32)
AND JUST ABOUT ALL OF EASTERN UPPER PROBABLY OUT OF THE MIX FOR
MUCH OF THE DAY. IN ADDITION TO EXPECTED AXIS OF DEFORMATION
FORCING...WILL LIKELY ALSO SEE SOME DIURNAL HELP TO THE PRECIP
WITHIN A QUITE MOIST AIRMASS...WITH SURFACE TEMPS INTO THE
LOWER/MIDDLE 70S PROMOTING MUCAPE VALUES UP TOWARD 700 J/KG. GIVEN
THE UPPER COLD POOL SKIRTING OVERHEAD AND A GOOD CHUNK OF
AVAILABLE INSTABILITY SITUATED ABOVE THE -12C ISOTHERM...SMALL
HAIL REMAINS A THREAT WITH ANY CONVECTION THAT DEVELOPS.
PER SATELLITE TRENDS...HAVE LOWERED GOING HIGHS A COUPLE OF
DEGREES INLAND WITH ONGOING UPSLOPE FLOW INTO THE HIGHER TERRAIN
LIKELY CAPPING THINGS AROUND 70 DEGREES...WITH DOWNSLOPE FLOW INTO
NORTHWEST LOWER KICKING THINGS TOWARD THE MID 70S. WARMEST SPOTS
WILL BE EASTERN UPPER WITH THINNING CLOUDS INTO THE AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 409 AM EDT FRI JUL 27 2012
EARLY MORNING SURFACE ANALYSIS SHOWS AN EAST-WEST ORIENTED TROUGH
AXIS LYING ACROSS SOUTHERN LOWER MICHIGAN/CENTRAL WISCONSIN.
COMPACT UPPER LOW WAS SPINNING SOUTHEAST INTO NORTHWEST
WISCONSIN...WITH A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ARCING
AROUND THIS CIRCULATION FROM THE MICHIGAN/WISCONSIN BORDER SOUTHWARD
ACROSS EASTERN WISCONSIN (WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD AHEAD OF THIS LOW SPREADING ACROSS LAKE MICHIGAN).
MEANWHILE...A FEW SPOTTY RADAR RETURNS DEVELOPED NORTH OF THE
SURFACE TROUGH AXIS SOUTH OF THE M-55 CORRIDOR WHERE LOW LEVEL LAPSE
RATES WERE LIKELY A LITTLE STEEPER PER 00Z DTX SOUNDING.
UPPER LEVEL FEATURE WILL CONTINUE TO TRACK SOUTHEAST AND CROSS
SOUTHERN LOWER MICHIGAN DURING THE DAY. WEAK RIDGE OF HIGH PRESSURE
WILL BUILD INTO NORTHERN MICHIGAN IN THE WAKE OF THIS SYSTEM TONIGHT.
TRACK OF THE UPPER LEVEL LOW SUGGESTS HIGHEST PRECIPITATION CHANCES
TODAY WILL BE ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
WILL BENEFIT THE MOST FROM THE SYNOPTIC COMPONENT WHICH SHOULD
ARRIVE THIS MORNING...PLUS STRONGEST DIURNAL COMPONENT WHERE LOW
LEVEL MOISTURE WILL BE MAXIMIZED AND MAY RESULT IN MLCAPE VALUES IN
THE 1000J/KG RANGE. PRECIPITATION CHANCES WILL BECOME MORE
SCATTERED TO THE NORTH WITH DRIER LOW LAYERS...AND LOOKING LIKE MOST
OF EASTERN UPPER WILL PROBABLY ESCAPE WITH LITTLE SIGNIFICANT
PRECIPITATION. THERMAL THROUGH ASSOCIATED WITH UPPER LEVEL WAVE
WILL LOWER FREEZING LEVELS...THUS STORMS WILL BE CAPABLE OF
PRODUCING HAIL. PLAN TO CARRY AN EXPLICIT MENTION OF SMALL HAIL
SOUTH OF A CVX-OSC LINE FROM LATE MORNING ONWARD. WARMEST HIGHS
TODAY WILL PROBABLY BE NORTH OF THE BRIDGE WHERE THERE WILL BE MORE
SUN ESPECIALLY LATER TODAY...IN GENERAL EXPECT HIGHS MAINLY IN THE
70S.
AS UPPER WAVE SLIPS INTO THE OHIO VALLEY THIS EVENING AND DRIER AIR
FILTERS INTO NORTHERN MICHIGAN IN ITS WAKE...THREAT FOR SHOWERS WILL
COME TO AN END ACROSS CENTRAL LOWER COUNTIES WITH SKIES CLEARING.
MAYBE A LITTLE PATCHY FOG ACROSS PARTS OF NORTHERN LOWER...BUT
SHOULD BE A SEASONABLY CHILLY NIGHT. COULD SEE A FEW SHELTERED
SPOTS DROPPING BELOW 50 EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM EDT FRI JUL 27 2012
CURRENT UPPER LEVEL PATTERN SET TO CHANGE LITTLE FOR THE FORESEEABLE
FUTURE...FEATURING INTERMOUNTAIN WEST/HIGH PLAINS RIDGING BOOKENDED BY
EASTERN NOAM AND FAR EAST PACIFIC TROUGHINESS. AS A RESULT...
RECENTLY ESTABLISHED NORTHWEST FLAVOR TO MID LEVEL FLOW OVER THE
LAKES WILL REMAIN REMARKABLY PERSISTENT...KEEPING TEMPERATURES
LOCKED IN TO NEAR NORMAL LEVELS AND ALLOWING PERIODIC RAIN CHANCES
AS OCCASIONAL DISTURBANCES ROTATE THROUGH THE REGION. FORECAST
CONCERNS RELEGATED TO THE LATTER OF THESE TWO...FOCUSING ON SHOWER
AND STORM CHANCES NEXT WORK WEEK.
RESERVOIR OF DRY CANADIAN AIR SWEEPS SOUTH INTO THE NORTHERN LAKES
BEHIND TOMORROWS DEPARTING SYSTEM...SETTING UP A MAINLY QUIET...DRY
WEEKEND. OVERHEAD HIGH PRESSURE EXPECTED TO LEAD TO EXCELLENT LAKE
BREEZE DEVELOPMENT SATURDAY...AND COMBINED WITH LINGERING 850MB
THERMAL TROUGH...SHOULD SET UP A PRETTY DECENT INLAND CU FIELD BY
AFTERNOON. FORMIDABLE MID LEVEL CAP EXPECTED TO KEEP CLOUD HEIGHTS
IN CHECK AND PREVENT ANY SHOWER DEVELOPMENT. LATEST PROGS STARTING
TO THROW SOME CONCERN INTO INHERITED DRY SUNDAY... ESPECIALLY ACROSS
EASTERN UPPER. SUBTLE MID LEVEL WAVE AND BEGINNINGS OF MODEST RETURN
FLOW NOW SUPPORTING SOME EASTERN UPPER SHOWERS BY AFTERNOON.
GUIDANCE IS NOTORIOUS FOR BRINGING IN MOISTURE TOO QUICKLY...
ESPECIALLY WITH AN ANTECEDENT RELATIVELY DRY AIR MASS. WILL REFRAIN
FROM INTRODUCING ANOTHER PERIOD OF LOW END SHOWER POTENTIAL (SEE
BELOW)...WAITING FOR MORE CONSISTENCY BEFORE DOING SO. NEAR SEASONAL
HIGH TEMPERATURES EXPECTED BOTH AFTERNOONS...WITH READINGS IN THE
UPPER 70S AND LOWER 80S.
"POTENTIALLY" SOMEWHAT MORE ACTIVE PERIOD OF WEATHER RETURNS NEXT
WORK WEEK...WITH ABOVE OUTLINED FLOW AT LEAST OPENING UP THE
OPPORTUNITY FOR A FEW DISTURBANCES TO ROTATE THROUGH THE REGION.
NOTHING EARTH SHATTERING PER TRENDS...WITH GUIDANCE SUGGESTING LOW
AMPLITUDE WAVES AND DEEPEST CORE OF MOISTURE TO REMAIN WELL TO OUR
SOUTHWEST. AS EXPECTED WITH THIS FLOW REGIME...EXACT TIMING REMAINS
PROBLEMATIC AT BEST...WITH THE ECMWF LAGGING BEHIND BOTH THE GFS AND
GEM BY SEVERAL HOURS WITH LEAD WAVE LATE SUNDAY NIGHT INTO MONDAY.
SIMPLY NOT PRUDENT AT THIS HOUR TO PICK ONE OVER THE OTHER...AND
WILL RIDE WITH LATE SUNDAY NIGHT INTO MONDAY LOW END RAIN CHANCES.
SAME GOES FOR MONDAY NIGHT AND TUESDAY AS ADDITIONAL SUPPORT
PINWHEELS OVER THE REGION. UNFORTUNATELY...BECAUSE OF SAID TIMING
CONCERNS...SIMPLY NO WAY TO SIDESTEP INHERITED MULTI-PERIOD RAIN
CHANCES...ALTHOUGH IN ALL LIKELIHOOD...MUCH OF THE TIME OUTLINED
ABOVE WILL REMAIN DRY. OF COURSE...TEMPERATURES DIRECTLY TIED TO
CONVECTIVE TRENDS...BUT OFF THE DECK THERMAL TRENDS SUGGEST HIGHS
BOTH MONDAY AND TUESDAY REMAINING IN THE UPPER 70S AND LOWER 80S.
PATTERN LOOKS TO SIMPLY REPEAT ITSELF LATER IN THE WEEK...WITH
TRENDS SUPPORTING A DRY MID WEEK PERIOD FOLLOWED BY ADDITIONAL RAIN
CHANCES THURSDAY INTO FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 132 AM EDT FRI JUL 27 2012
COMPLEX AND CHALLENGING CLOUD FORECAST THROUGH FIRST HALF OF TAF
PERIOD. AREAS OF MVFR FOG/LOWER CLOUDS OVERNIGHT...WITH INCREASING
CHANCES OF SHOWERS TOWARD 12Z AS UPPER LOW OVER WESTERN SUPERIOR
APPROACHES THE AREA. LOCALIZED IFR VSBY/S POSSIBLE DUE TO FOG
BEFORE THE SHOWERS ARRIVE. CIGS GENERALLY MVFR FOR THE FIRST HALF
OF FRIDAY WITH SCATTERED SHOWERS AND A FEW THUNDERSTORMS. CIGS
STEADILY IMPROVING BY LATER FRIDAY AFTERNOON AS UPPER LOW DEPARTS
AND DRIER AIR BEGINS TO MOVE IN FROM THE NORTHWEST.
WINDS LESS THAN 10 KNOTS THROUGHOUT THE NEXT 24 HOURS.
&&
.MARINE...
ISSUED AT 409 AM EDT FRI JUL 27 2012
EAST/NORTHEAST WINDS EXPECTED TODAY ACROSS THE UPPER LAKES...WITH
THE FORECAST AREA SANDWICHED BETWEEN A TROUGH OF LOW PRESSURE
DROPPING SOUTH TOWARD THE OHIO VALLEY AND A WEAK RIDGE OF HIGH
PRESSURE BUILDING IN FROM THE NORTH. WINDS WILL BACK MORE TOWARD
THE NORTH TONIGHT BUT GRADIENT WILL BE WEAKENING AS AFOREMENTIONED
RIDGE BUILDS IN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...JK
MARINE...JPB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
647 AM EDT FRI JUL 27 2012
.AVIATION...
//DISCUSSION...
NE FLOW OFF LAKE HURON HAS HELPED KEEP SURFACE MOISTURE ELEVATED
THUS HAS PRODUCED WIDESPREAD STRATUS. BETWEEN THE LOW STRATUS AND
LINGERING PATCHY FOG...MVFR CONDITIONS COULD CONTINUE FOR A COUPLE
MORE HOURS BEFORE LIFTING BACK TO VFR FOR THE AFTERNOON. THE STRATUS
HAS DONE A GOOD JOB KEEPING MOST OF THE FOG CONTAINED OVER SW LOWER
MI WITH HINTS OF IT APPROACHING FNT AND PTK AT TIMES. SURFACE LOW
PRESSURE SYSTEM APPROACHING LAKE MICHIGAN WILL REACH SE MI THIS
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS HAVE ALREADY STARTED
POPPING UP THIS MORNING BUT COVERAGE WILL INCREASE INTO THE
AFTERNOON AS DIURNAL HEATING AIDES IN THE DEVELOPMENT OF
PRECIPITATION. THIS MORNINGS COVERAGE WILL BE TOO ISOLATED TO
INCLUDE IN THE TAFS AT THIS TIME. HAVE CONTINUED THE MENTION OF
SHOWERS AFTER 18Z SINCE COVERAGE SHOULD BE MORE WIDESPREAD DURING
THAT TIME. WILL HOLD OFF ON MENTIONING THUNDER UNTIL WE CAN GET
BETTER TIMING OF THE STRONGER STORMS.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET AT LEAST
INTERMITTENTLY ON FRIDAY...BUT LOW CONFIDENCE ON TIMING.
* MEDIUM CONFIDENCE IN THUNDERSTORM DEVELOPMENT ON FRIDAY...BUT LOW
CONFIDENCE IN TIMING AND LOCATION.
&&
.PREV DISCUSSION...ISSUED 339 AM EDT FRI JUL 27 2012
SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
339 AM EDT FRI JUL 27 2012
.SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
&&
.MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.AVIATION...ISSUED 118 AM EDT FRI JUL 27 2012
//DISCUSSION...
POCKETS OF LOWER STRATUS CONTINUE TO EMERGE WITHIN THE POST-FRONTAL
LOW LEVEL NORTHEAST FLOW LATE THIS EVENING. THIS TREND WILL LIKELY
PERSIST THROUGH THE NIGHT...WITH THE FRONTAL BOUNDARY POSITIONED
JUST THE WEST. LOWEST CEILINGS WILL TEND TO EXIST ACROSS THE
NORTHERN TAF SITES...WHERE CONDITIONS WILL AT LEAST INTERMITTENTLY
DIP INTO MVFR /IFR AT PTK THANKS TO THE ELEVATION/. PROSPECTS FOR
SOME AREAS OF FOG STILL EXIST GIVEN THE MOIST BOUNDARY LAYER
CONDITIONS. THE HIGHER DEGREE OF CLOUD COVERAGE...AND PERHAPS SOME
PERSISTENCE IN THE LOW LEVEL GRADIENT FLOW...WOULD SEEMINGLY DETER A
MORE WIDESPREAD/THICKER FOG ISSUE. THE GROWING MID LEVEL
INSTABILITY ATTENDANT TO AN APPROACHING WAVE WILL ALLOW
PRECIPITATION TO INCREASE IN COVERAGE THROUGH THE DAY ON FRIDAY.
STILL A BIT EARLY TO PROVIDE SPECIFIC TIMING ON THUNDERSTORM
POTENTIAL.
EXPANDING AREA OF PRECIPITATION ON FRIDAY.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET AT LEAST
INTERMITTENTLY ON FRIDAY...BUT LOW CONFIDENCE ON TIMING.
* MEDIUM CONFIDENCE IN THUNDERSTORM DEVELOPMENT ON FRIDAY...BUT LOW
CONFIDENCE IN TIMING AND LOCATION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
AVIATION.....MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1126 PM CDT THU JUL 26 2012
.UPDATE...
ISSUED AT 730 PM CDT THU JUL 26 2012
HAVE EXPANDED THE MENTION OF ISOLATED SHOWERS AND THUNDERSTORMS
FURTHER SOUTH TOWARD CENTRAL PORTIONS OF THE CWA THIS EVENING. A
BROKEN LINE OF CONVECTION EXTENDING FROM NORTH CENTRAL MISSOURI
AND INTO CENTRAL ILLINOIS CONTINUES TO DRIFT SOUTHWARD...THOUGH
GIVEN INDICATIONS FROM HRRR MODEL OUTPUT AND THE LOSS OF DAYTIME
HEATING...THE EXPECTATION IS FOR THESE STORMS TO TAPER OFF THROUGH
THE LATE EVENING HOURS.
OTHERWISE...GOING FORECAST REMAINS ON TRACK WITH ONLY MINOR
CHANGES TO SHORT TERM TRENDS NEEDED FOR AREAS CO-LOCATED WITH
CONVECTION THIS EVENING.
PHILLIPSON
&&
.SYNOPSIS...
ISSUED AT 216 PM CDT THU JUL 26 2012
591DAM HIGH AT 500MB HAS SPLIT INTO TWO CENTERS...ONE LOCATED
ACROSS ARIZONA AND THE OTHER OVER LOUISIANA. IN BETWEEN...THE WELL
ADVERTISED TROF OF LOW PRESSURE EXTENDS FROM LAKE SUPERIOR TO
TEXAS.
OVERNIGHT MCS DISSIPATED ON SCHEDULE AS IT ENCOUNTERED THE REMAINING
RIDGE AXIS THAT AT 12Z WAS STILL POKING UP ALONG THE MISSISSIPPI
RIVER. THINNING CLOUD COVER AND VERY WARM 850MB TEMPERATURES ABOVE
20C RESULTED IN TEMPERATURES JUMPING BACK INTO THE 90S. TRUE SURFACE
COLD FRONT IS JUST NOW ENTERING THE NORTHWEST CORNER OF THE
CWA...BUT DEEP CONVECTION IS FIRING ALONG AND SOUTH OF THE OUTFLOW
BOUNDARY (SOUTHERN MISSOURI AND ILLINOIS).
CVKING
&&
.SHORT TERM...
ISSUED AT 216 PM CDT THU JUL 26 2012
(TONIGHT THROUGH SUNDAY)
COLD FRONT WILL MAKE STEADY PROGRESS SOUTH ACROSS THE CWA...WITH
FOCUS FOR DEEP CONVECTION QUICKLY MOVING SOUTH AND EAST OF THE CWA
THIS EVENING. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH DEWPOINTS
SLOW TO FALL BEHIND THE FRONT.
DEEP MIXING...ABOVE 800 MB...WILL RESULT IN ANOTHER HOT DAY ON
FRIDAY FOR MOST OF THE CWA. ONLY EXCEPTION IS FAR NORTH THAT WILL
ONLY BE MIXING MIDDLE/UPPER TEEN TEMPERATURES FROM 850MB RATHER THAN
+20C. WILL BE EXTENDING HEAT HEADLINES ONE MORE DAY WITH FORECAST
HIGHS IN THE UPPER 90S TO 100 DEGREES. DEEP MIXING WILL SEND
DEWPOINTS TANKING IN THE AFTERNOON DUE TO DRIER AIR ALOFT BEHIND THE
FRONT. HEAT INDEX VALUES WILL NOT REACH OFFICIAL CRITERIA...BUT DONT
WANT TO SEND THE WRONG MESSAGE...WE HAVE ONE MORE HOT DAY BEFORE
COOLER AIR FILTERS IN FOR SATURDAY.
AREA MAY EXPERIENCE RED FLAG CONDITIONS TOMORROW AFTERNOON...GIVEN
DROUGHT CONDITIONS...LOW RELATIVE HUMIDITY AND NORTHWEST WINDS. WILL
LET MIDSHIFT DETERMINE THE NEED FOR THE HEADLINE BASED ON LATEST
MODEL DATA AND RAINFALL REPORTS.
850MB THERMAL AXIS SHIFTS FURTHER TO THE WEST ON SATURDAY WITH
COOLER...YET STILL ABOVE NORMAL...TEMPERATURES EXPECTED. WITH DEEP
MIXING AND PLENTY OF SUNSHINE HAVE FORECAST HIGHS A DEGREE OR TWO
WARMER THAN THE WARMEST MET MOS.
PROSPECT FOR PRECIPITATION DOES INCREASE SATURDAY NIGHT AND SUNDAY
AS MODELS PORTRAY NOCTURNAL CONVECTION DEVELOPING ACROSS THE CENTRAL
PLAINS ON THE NOSE OF A LOW LEVEL JET. HAVE INCREASED CLOUD COVER
AND POPS SATURDAY NIGHT AND SUNDAY ACROSS NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS WHERE DECAYING CONVECTION WOULD PROPAGATE. IF
THIS OCCURS...TEMPERATURES MAY END UP COOLER THAN CURRENTLY FORECAST
FOR SUNDAY.
CVKING
&&
.LONG TERM...
ISSUED AT 216 PM CDT THU JUL 26 2012
(MONDAY THROUGH THURSDAY)
MODELS AGREE THAT AN ACTIVE NORTHWEST FLOW PATTERN WILL SET UP
ACROSS THE AREA FOR THE REMAINDER OF THE FORECAST AS THE UPPER LEVEL
RIDGE EXPANDS ACROSS THE ROCKIES/PLAINS AND A TROF DEEPENS OVER THE
EAST COAST. PINNING DOWN PRECIPITATION CHANCES IN THIS TYPE OF A
PATTERN IS VERY DIFFICULT DUE TO THE TIMING/TRACK OF WEAK
SHORTWAVES. TO ADD SALT TO THE WOUND...MODEL GUIDANCE HAS BEEN FAR
TOO ROBUST WITH PRECIPITATION DEVELOPMENT THE PAST FEW MONTHS DUE TO
THE EXTREME DROUGHT CONDITIONS. THEREFORE WILL REMAIN VERY
CONSERVATIVE IN FORECASTING PRECIPITATION IN THE EXTENDED PERIODS OF
THE FORECAST.
TEMPERATURES WILL REMAIN ABOVE NORMAL WITH EXACT VALUES BEING HIGHLY
DE PENDANT ON THE SURFACE FRONTAL POSITION...CLOUD COVER AND ANY
PRECIPITATION THAT IS OBSERVED. 850MB TEMPERATURES RANGE FROM THE
LOWER 20S ACROSS CENTRAL MISSOURI TO THE UPPER TEENS IN CENTRAL
ILLINOIS...WHICH SUPPORTS SURFACE TEMPERATURES NEAR 100 DEGREES IN
CENTRAL MISSOURI AND MIDDLE 90S IN CENTRAL ILLINOIS. DEWPOINTS MAY
POOL NEXT WEEK WITH THE CLOSE PROXIMITY OF THE FRONTAL POSITION AND
LEAD TO HEAT INDEX VALUES RISING BACK ABOVE 100 DEGREES AT TIMES.
CVKING
&&
.AVIATION...
ISSUED AT 1126 PM CDT THU JUL 26 2012
STORMS CONTINUE TO FIREUP OVER NORTHEAST MO/WEST CENTRAL IL AND
SLIDE SOUTHEAST AHEAD OF COLD FRONT...BUT DISSIPATE BEFORE
REACHING INTERSTATE 70. RECENT CLUSTER TRIED TO MOVE INTO
KUIN...BUT DIMINISHED BEFORE REACHING TAF SITE. SO CONFIDENCE IS
LOW THAT THIS CURRENT ACTIVITY WILL REACH METRO AREA...SO WILL
LEAVE TAFS DRY FOR NOW.
OTHERWISE...WINDS WILL BE LIGHT AND VARIABLE THROUGH 14Z-15Z BEFORE
COLD FRONT MOVES ACROSS THE AREA. NORTHWEST TO NORTH WINDS BETWEEN
10 AND 15KTS TO PERSIST ACROSS FORECAST AREA TODAY BEFORE
DIMINISHING ONCE AGAIN THIS EVENING.
SPECIFICS FOR KSTL...ANOTHER BATCH OF STORMS TO THE NORTHWEST OF
METRO AREA CONTINUES TO SLOWLY DIMINISH AS IT MOVES SOUTHEAST...SO
CONFIDENCE IS LOW THAT IT WILL REACH KSTL. SO KEPT TAF DRY FOR
NOW. OTHERWISE...WINDS WILL BE LIGHT AND VARIABLE THROUGH 15Z
BEFORE COLD FRONT MOVES ACROSS THE AREA. NORTHWEST WINDS NEAR 15KTS
TO PERSIST ACROSS METRO AREA TODAY BEFORE DIMINISHING ONCE
AGAIN BY 01Z SATURDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR AUDRAIN MO-BOONE MO-
CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-MONITEAU MO-
MONTGOMERY MO-OSAGE MO-PIKE MO-REYNOLDS MO-ST. FRANCOIS MO-
STE. GENEVIEVE MO-WARREN MO-WASHINGTON MO.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT FRIDAY FOR ST. CHARLES MO-
ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR BOND IL-CALHOUN IL-
CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-
MARION IL-MONROE IL-MONTGOMERY IL-RANDOLPH IL-WASHINGTON IL.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT FRIDAY FOR MADISON IL-ST.
CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
932 PM MDT SAT JUL 28 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
SCATTERED THUNDERSTORMS AND RAIN SHOWERS EASILY MANAGED TO BRING
STRONG WINDS ALOFT TO THE SURFACE RESULTING IN STRONG GUSTY WINDS
AND NOT A LOT OF ASSOCIATED QPF. SEVERAL WIND GUSTS TO AROUND 60
MPH PROMPTED A COUPLE OF SEVERE WARNINGS FOR WINDS ONLY. WIND
GUSTS ARE EXPECTED TO DIMINISH AS THE SUN SETS. UPDATED AGAIN
BASED ON RADAR TRENDS. BOTH THE GFS AND NAM HAVE BEEN CLUELESS BUT
THE RAP MODEL AT LEAST GAVE HINTS OF PRECIPITATION. SO BASED ON
THE RAP WILL SPREAD ISOLATED ACROSS THE CWA TONIGHT SINCE
THUNDERSTORMS CAN ALREADY BE SEEN UPSTREAM MOVING IN OUR
DIRECTION. SCT
PREVIOUS UPDATE DISCUSSION...
THE MODELS HAVE NOT BEEN MUCH HELP IN THE WAY OF PREDICTING WHERE
THUNDERSTORMS WILL DEVELOP. EARLY THIS EVENING A NORTH-SOUTH LINE
DEVELOPED IN BLAINE AND FERGUS COUNTIES THAT HAVE SINCE DRIFTED
EAST INTO PHILLIPS COUNTY. THE LINE HAD VIL UP TO 50 THAT HAS NOW
DIMINISHED TO LESS THAN 30. SO DO NOT EXPECT MUCH IN THE WAY OF
HAIL. THE CONCERN WAS STRONG WIND GUSTS...WITH 48 MPH WINDS WITH
GUSTS TO 59 MPH AT HAVRE RECORDED EARLIER. CALLS TO SPOTTERS IN
PHILLIPS COUNTY HAVE ONLY FOUND WIND GUSTS TO AROUND 30-35 MPH. SO
EXPECT THIS LINE TO HOLD TOGETHER A LITTLE WHILE LONGER TO MAINLY
PRODUCE RAIN WITH MODERATE WIND GUSTS. HOWEVER WILL CONTINUE TO
MONITOR FOR WINDS. THE 00Z GGW SOUNDING REVEALED WEAK INSTABILITY
SO DO NOT EXPECT STORMS TO GO SEVERE AT THIS TIME. SCT
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD LOOK MUCH THE SAME AS
THEY DID AT THIS TIME YESTERDAY...BUT TODAY...THE STRENGTH AND
EXTENT OF THE UPPER LEVEL DOME OF HIGH PRESSURE OVER THE CENTRAL
HIGH PLAINS IS BEING CHALLENGED BY MULTIPLE EMBEDDED SMALLER SCALE
SHORT WAVE DISTURBANCES RIDING OVER THE TOP OF THE RIDGE.
FORECAST CHALLENGES WILL FOCUS ON HOW STRONG OR SEVERE THE
THUNDERSTORM THREAT IS TONIGHT. IT SEEMS THAT EVERY SHORT TERM
MODEL SOLUTION HAS A DIFFERENT IDEA ON WHAT IS GOING TO OR NOT
GOING TO HAPPEN. A FEW CLOUDS AND SOME SCATTERED STORMS CURRENTLY
GETTING STARTED OUT THERE OVER CENTRAL AND WESTERN MONTANA. SPC
OUTLOOK FOR THIS AFTERNOON AND EVENING PUTS A SLIGHT RISK AREA
OVER OUR SOUTH-CENTRAL AND SOUTH-WESTERN ZONES. THE GRID TIME FOR
NOW THROUGH 00Z SHOWS SIGNIFICANT MODEL QPF OUTPUT DISCREPANCIES.
GFS WANTS TO KEEP THE ENTIRE CWA DRY WHILE THE NAM WANTS TO BRING
IN AT LEAST A WETTING RAIN TO OUR SOUTH-WESTERN...NORTH-
WESTERN...AND FAR NORTH-EASTERN ZONES. THE HRRR WANTS TO PUSH
THROUGH A SCATTERED NORTH-TO-SOUTH ORIENTED LINE OF STORMS...BUT
EACH SUCCESSIVE MODEL RUN DELAYS THE ONSET OF STORMS AND BREAKS UP
THE LINE EVEN MORE. HARD TO KNOW WHICH MODEL TO TRUST AT THIS
TIME.
TONIGHT THROUGH SUNDAY...SHORT TERM MODELS SHOW BETTER AGREEMENT
AND KEEP SOME LINGERING PRECIPITATION NEAR THE SOUTHERN AND NORTH-
EASTERN PERIMETERS OF OUR CWA.
SUNDAY NIGHT THROUGH MONDAY...THE UPPER LEVEL RIDGE AXIS RE-
STRENGTHENS THROUGH MONTANA AND CUTS OF THE MOISTURE
FLOW...ALLOWING FOR HOT TEMPERATURES AND SUNNY SKIES TO DOMINATE
THROUGH THE FORECAST PERIOD. BMICKELSON
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
GOOD MODEL CONSISTENCY IN THE SYNOPTIC PATTERN LEADS TO HIGH
CONFIDENCE THAT OUR AREA WILL REMAIN LARGELY UNDER THE INFLUENCE
OF AN UPPER LEVEL RIDGE CENTERED OVER THE SRN HI PLAINS THROUGH
WED NIGHT. THE TRICKY PART OF THE FORECAST IS TIMING OF WEAK
SHORTWAVES RIDING THROUGH THE RIDGE AXIS. THERE DOES SEEM TO BE
DECENT AGREEMENT AT LEAST AMONG A FEW OF THE MODELS THAT MON NIGHT
AND EARLY TUESDAY WILL BE UNSETTLED AS CONVECTION INITIATES ALONG
A SURFACE BOUNDARY ACROSS NORTHEAST MT AND MOVES EAST. SO HAVE
RELATIVELY HIGHER POPS IN THE CHANCE CATEGORY FOR THAT PERIOD.
TEMPERATURES WILL REMAIN WARMER THAN NORMAL THROUGH THE MIDDLE OF
THE WEEK.
BY LATE WEDNESDAY INTO THURSDAY AN UPPER LEVEL TROUGH MOVING
ONSHORE OVER BRITISH COLUMBIA WILL TRACK EASTWARD AND SUPPRESS THE
RIDGE AXIS...USHERING COOLER...NEAR TO BELOW NORMAL...AIR SOUTH
INTO MT BY THE END OF THE WEEK. RAIN CHANCES WILL DEPEND ON HOW
FAR SOUTH THE ENERGY WITH THIS SHORTWAVE ACTUALLY TRACKS. FOR
NOW...LEFT POPS IN THE SLIGHT CHANCE OR LESS CATEGORY. MOYER
&&
.AVIATION...
29/00Z...VFR. LINE OF TSRA MOVING TOWARDS KGGW AT 00Z EXPECTED TO
ARRIVE BY 03Z IF IT HOLDS TOGETHER. EXPECT WIND GUSTS TO 40 KNOTS
AS THE MAIN ISSUE WITH THIS LINE. BRIEF MVFR VISIBILITIES POSSIBLE
WITH BLOWING DUST FROM STORM OUTFLOW. HRRR IS A LITTLE SLOW...
HOWEVER DOES HAVE THE LINE OF TSRA AND IS USABLE TO PROVIDE FAIR
CONFIDENCE IN THE STORMS FOR KGGW. FOR THE OTHER TERMINALS THE
STORMS ARE EXPECTED TO WEAKEN BEFORE THEY REACH THOSE SITES. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
702 PM MDT SAT JUL 28 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
THE MODELS HAVE NOT BEEN MUCH HELP IN THE WAY OF PREDICTING WHERE
THUNDERSTORMS WILL DEVELOP. EARLY THIS EVENING A NORTH-SOUTH LINE
DEVELOPED IN BLAINE AND FERGUS COUNTIES THAT HAS SINCE DRIFTED
EAST INTO PHILLIPS COUNTY. THE LINE HAD VIL UP TO 50 THAT HAS NOW
DIMINISHED TO LESS THAN 30. SO DO NOT EXPECT MUCH IN THE WAY OF
HAIL. THE CONCERN WAS STRONG WIND GUSTS...WITH 48 MPH WINDS WITH
GUSTS TO 59 MPH AT HAVRE RECORDED EARLIER. CALLS TO SPOTTERS IN
PHILLIPS COUNTY HAVE ONLY FOUND WIND TEMPORARY GUSTS TO AROUND
30-35 MPH. SO EXPECT THIS LINE TO HOLD TOGETHER A LITTLE WHILE
LONGER TO MAINLY PRODUCE RAIN WITH MODERATE WIND GUSTS. HOWEVER
WILL CONTINUE TO MONITOR FOR WINDS. THE 00Z GGW SOUNDING REVEALED
WEAK INSTABILITY SO DO NOT EXPECT STORMS TO GO SEVERE AT THIS
TIME. SCT
PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD LOOK MUCH THE SAME AS
THEY DID AT THIS TIME YESTERDAY...BUT TODAY...THE STRENGTH AND
EXTENT OF THE UPPER LEVEL DOME OF HIGH PRESSURE OVER THE CENTRAL
HIGH PLAINS IS BEING CHALLENGED BY MULTIPLE EMBEDDED SMALLER SCALE
SHORT WAVE DISTURBANCES RIDING OVER THE TOP OF THE RIDGE.
FORECAST CHALLENGES WILL FOCUS ON HOW STRONG OR SEVERE THE
THUNDERSTORM THREAT IS TONIGHT. IT SEEMS THAT EVERY SHORT TERM
MODEL SOLUTION HAS A DIFFERENT IDEA ON WHAT IS GOING TO OR NOT
GOING TO HAPPEN. A FEW CLOUDS AND SOME SCATTERED STORMS CURRENTLY
GETTING STARTED OUT THERE OVER CENTRAL AND WESTERN MONTANA. SPC
OUTLOOK FOR THIS AFTERNOON AND EVENING PUTS A SLIGHT RISK AREA
OVER OUR SOUTH-CENTRAL AND SOUTH-WESTERN ZONES. THE GRID TIME FOR
NOW THROUGH 00Z SHOWS SIGNIFICANT MODEL QPF OUTPUT DISCREPANCIES.
GFS WANTS TO KEEP THE ENTIRE CWA DRY WHILE THE NAM WANTS TO BRING
IN AT LEAST A WETTING RAIN TO OUR SOUTH-WESTERN...NORTH-
WESTERN...AND FAR NORTH-EASTERN ZONES. THE HRRR WANTS TO PUSH
THROUGH A SCATTERED NORTH-TO-SOUTH ORIENTED LINE OF STORMS...BUT
EACH SUCCESSIVE MODEL RUN DELAYS THE ONSET OF STORMS AND BREAKS UP
THE LINE EVEN MORE. HARD TO KNOW WHICH MODEL TO TRUST AT THIS
TIME.
TONIGHT THROUGH SUNDAY...SHORT TERM MODELS SHOW BETTER AGREEMENT
AND KEEP SOME LINGERING PRECIPITATION NEAR THE SOUTHERN AND NORTH-
EASTERN PERIMETERS OF OUR CWA.
SUNDAY NIGHT THROUGH MONDAY...THE UPPER LEVEL RIDGE AXIS RE-
STRENGTHENS THROUGH MONTANA AND CUTS OF THE MOISTURE
FLOW...ALLOWING FOR HOT TEMPERATURES AND SUNNY SKIES TO DOMINATE
THROUGH THE FORECAST PERIOD. BMICKELSON
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
GOOD MODEL CONSISTENCY IN THE SYNOPTIC PATTERN LEADS TO HIGH
CONFIDENCE THAT OUR AREA WILL REMAIN LARGELY UNDER THE INFLUENCE
OF AN UPPER LEVEL RIDGE CENTERED OVER THE SRN HI PLAINS THROUGH
WED NIGHT. THE TRICKY PART OF THE FORECAST IS TIMING OF WEAK
SHORTWAVES RIDING THROUGH THE RIDGE AXIS. THERE DOES SEEM TO BE
DECENT AGREEMENT AT LEAST AMONG A FEW OF THE MODELS THAT MON NIGHT
AND EARLY TUESDAY WILL BE UNSETTLED AS CONVECTION INITIATES ALONG
A SURFACE BOUNDARY ACROSS NORTHEAST MT AND MOVES EAST. SO HAVE
RELATIVELY HIGHER POPS IN THE CHANCE CATEGORY FOR THAT PERIOD.
TEMPERATURES WILL REMAIN WARMER THAN NORMAL THROUGH THE MIDDLE OF
THE WEEK.
BY LATE WEDNESDAY INTO THURSDAY AN UPPER LEVEL TROUGH MOVING
ONSHORE OVER BRITISH COLUMBIA WILL TRACK EASTWARD AND SUPPRESS THE
RIDGE AXIS...USHERING COOLER...NEAR TO BELOW NORMAL...AIR SOUTH
INTO MT BY THE END OF THE WEEK. RAIN CHANCES WILL DEPEND ON HOW
FAR SOUTH THE ENERGY WITH THIS SHORTWAVE ACTUALLY TRACKS. FOR
NOW...LEFT POPS IN THE SLIGHT CHANCE OR LESS CATEGORY. MOYER
&&
.AVIATION...
29/00Z...VFR. LINE OF TSRA MOVING TOWARDS KGGW AT 00Z EXPECTED TO
ARRIVE BY 03Z IF IT HOLDS TOGETHER. EXPECT WIND GUSTS TO 40 KNOTS
AS THE MAIN ISSUE WITH THIS LINE. BRIEF MVFR VISIBILITIES POSSIBLE
WITH BLOWING DUST FROM STORM OUTFLOW. HRRR IS A LITTLE SLOW...
HOWEVER DOES HAVE THE LINE OF TSRA AND IS USABLE TO PROVIDE FAIR
CONFIDENCE IN THE STORMS FOR KGGW. FOR THE OTHER TERMINALS THE
STORMS ARE EXPECTED TO WEAKEN BEFORE THEY REACH THOSE SITES.
PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
626 PM MDT SAT JUL 28 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD LOOK MUCH THE SAME AS
THEY DID AT THIS TIME YESTERDAY...BUT TODAY...THE STRENGTH AND
EXTENT OF THE UPPER LEVEL DOME OF HIGH PRESSURE OVER THE CENTRAL
HIGH PLAINS IS BEING CHALLENGED BY MULTIPLE EMBEDDED SMALLER SCALE SHORT
WAVE DISTURBANCES RIDING OVER THE TOP OF THE RIDGE.
FORECAST CHALLENGES WILL FOCUS ON HOW STRONG OR SEVERE THE
THUNDERSTORM THREAT IS TONIGHT. IT SEEMS THAT EVERY SHORT TERM
MODEL SOLUTION HAS A DIFFERENT IDEA ON WHAT IS GOING TO OR NOT
GOING TO HAPPEN. A FEW CLOUDS AND SOME SCATTERED STORMS CURRENTLY
GETTING STARTED OUT THERE OVER CENTRAL AND WESTERN MONTANA. SPC
OUTLOOK FOR THIS AFTERNOON AND EVENING PUTS A SLIGHT RISK AREA
OVER OUR SOUTH-CENTRAL AND SOUTH-WESTERN ZONES. THE GRID TIME FOR
NOW THROUGH 00Z SHOWS SIGNIFICANT MODEL QPF OUTPUT DISCREPANCIES.
GFS WANTS TO KEEP THE ENTIRE CWA DRY WHILE THE NAM WANTS TO BRING
IN AT LEAST A WETTING RAIN TO OUR SOUTH-WESTERN...NORTH-
WESTERN...AND FAR NORTH-EASTERN ZONES. THE HRRR WANTS TO PUSH
THROUGH A SCATTERED NORTH-TO-SOUTH ORIENTED LINE OF STORMS...BUT
EACH SUCCESSIVE MODEL RUN DELAYS THE ONSET OF STORMS AND BREAKS UP
THE LINE EVEN MORE. HARD TO KNOW WHICH MODEL TO TRUST AT THIS
TIME.
TONIGHT THROUGH SUNDAY...SHORT TERM MODELS SHOW BETTER AGREEMENT
AND KEEP SOME LINGERING PRECIPITATION NEAR THE SOUTHERN AND NORTH-
EASTERN PERIMETERS OF OUR CWA.
SUNDAY NIGHT THROUGH MONDAY...THE UPPER LEVEL RIDGE AXIS RE-
STRENGTHENS THROUGH MONTANA AND CUTS OF THE MOISTURE
FLOW...ALLOWING FOR HOT TEMPERATURES AND SUNNY SKIES TO DOMINATE
THROUGH THE FORECAST PERIOD. BMICKELSON
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
GOOD MODEL CONSISTENCY IN THE SYNOPTIC PATTERN LEADS TO HIGH
CONFIDENCE THAT OUR AREA WILL REMAIN LARGELY UNDER THE INFLUENCE
OF AN UPPER LEVEL RIDGE CENTERED OVER THE SRN HI PLAINS THROUGH
WED NIGHT. THE TRICKY PART OF THE FORECAST IS TIMING OF WEAK
SHORTWAVES RIDING THROUGH THE RIDGE AXIS. THERE DOES SEEM TO BE
DECENT AGREEMENT AT LEAST AMONG A FEW OF THE MODELS THAT MON NIGHT
AND EARLY TUESDAY WILL BE UNSETTLED AS CONVECTION INITIATES ALONG
A SURFACE BOUNDARY ACROSS NORTHEAST MT AND MOVES EAST. SO HAVE
RELATIVELY HIGHER POPS IN THE CHANCE CATEGORY FOR THAT PERIOD.
TEMPERATURES WILL REMAIN WARMER THAN NORMAL THROUGH THE MIDDLE OF
THE WEEK.
BY LATE WEDNESDAY INTO THURSDAY AN UPPER LEVEL TROUGH MOVING
ONSHORE OVER BRITISH COLUMBIA WILL TRACK EASTWARD AND SUPPRESS THE
RIDGE AXIS...USHERING COOLER...NEAR TO BELOW NORMAL...AIR SOUTH
INTO MT BY THE END OF THE WEEK. RAIN CHANCES WILL DEPEND ON HOW
FAR SOUTH THE ENERGY WITH THIS SHORTWAVE ACTUALLY TRACKS. FOR
NOW...LEFT POPS IN THE SLIGHT CHANCE OR LESS CATEGORY. MOYER
&&
.AVIATION...
29/00Z...VFR. LINE OF TSRA MOVING TOWARDS KGGW AT 00Z EXPECTED TO
ARRIVE BY 03Z IF IT HOLDS TOGETHER. EXPECT WIND GUSTS TO 40 KNOTS
AS THE MAIN ISSUE WITH THIS LINE. BRIEF MVFR VISIBILITIES POSSIBLE
WITH BLOWING DUST FROM STORM OUTFLOW. HRRR IS A LITTLE SLOW...
HOWEVER DOES HAVE THE LINE OF TSRA AND IS USABLE TO PROVIDE FAIR
CONFIDENCE IN THE STORMS FOR KGGW. FOR THE OTHER TERMINALS THE
STORMS ARE EXPECTED TO WEAKEN BEFORE THEY REACH THOSE SITES. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS HASTINGS NE
656 PM CDT SAT JUL 28 2012
.UPDATE...IT WAS A DIFFICULT CALL ON WHETHER TO GO WITH A SEVERE
THUNDERSTORM WATCH THIS EVENING AND IT WAS DISCUSSED AT LENGTH
WITH SEVERAL SURROUNDING OFFICES. CONVECTION THUS FAR HAS BEEN
RATHER MARGINAL ALTHOUGH A FEW STORMS HAVE SHOWN RECENT SIGNS OF
STRENGTHENING AND THE ENVIRONMENT IS MORE SUPPORTIVE THAN WE HAVE
SEEN FOR SOME TIME WITH DEEP LAYER SHEAR VALUES OF OVER 50 KTS
ACROSS OUR NORTH. THESE ARE VERY GOOD SHEAR VALUES FOR THIS TIME
OF YEAR. ACROSS OUR SOUTH THE SHEAR IS MUCH WEAKER AT AROUND 20
KTS...BUT THE STEEP LAPSE RATES AND INVERTED V SOUNDINGS ARE
INDICATIVE OF AN ENHANCED WIND THREAT ACROSS KANSAS ZONES AND
PORTIONS OF SOUTHERN NEBRASKA. THERE IS ALSO PLENTY OF CAPE WITH
MLCAPE VALUES RANGING FROM 1500 J/KG ACROSS KANSAS TO 2500 J/KG
OVER NEBRASKA. ULTIMATELY IT WAS DECIDED TO GO WITH A SEVERE
THUNDERSTORM WATCH THROUGH 1 AM.
&&
.AVIATION...00Z KGRI TAF. THUNDERSTORMS HAVE DEVELOPED ACROSS
SOUTH CENTRAL NEBRASKA AND COULD MOVE INTO THE KGRI VICINITY.
STILL TOO EARLY TO TELL IF ONE WILL DIRECTLY HIT KGRI OR NOT. SO
FAR THE ACTIVITY IS FAIRLY ISOLATED AN THUS HAVE ONLY INCLUDED
VICINITY WORDING IN THE TAF. THE WIND WILL BE LIGHT OUTSIDE OF
THUNDERSTORMS...BUT COULD BE VERY GUSTY SHOULD A THUNDERSTORM NEAR
THE AREA. THUNDERSTORM ACTIVITY WILL DIMINISH BY LATE EVENING.
&&
.PREV DISCUSSION... /ISSUED 412 PM CDT SAT JUL 28 2012/
SHORT TERM...THROUGH LATE SUNDAY AFTERNOON. THE MOST IMPORTANT
ISSUE OVER THE NEXT 24 HOURS IS MONITORING FOR STRONG TO SEVERE
CONVECTION MAINLY THROUGH MIDNIGHT TONIGHT...WITH SECONDARY
CONCERNS CONSISTING OF NEAR HEAT ADVISORY CONDITIONS MAINLY IN
NORTH CENTRAL KS ZONES SUNDAY AFTERNOON...AND ALSO VERY-NEAR
CRITICAL FIRE WEATHER CONDITIONS THROUGH EARLY THIS EVENING IN
SOUTHWEST ZONES.
19Z OBJECTIVE SURFACE ANALYSIS INDICATES WHAT ESSENTIALLY AMOUNTS
TO A TRIPLE POINT ACROSS SOUTHWEST PORTIONS OF THE CWA...AS A
WELL-DEFINED NORTHWEST-SOUTHEAST ORIENTED WARM FRONT CONTINUES
SURGING NORTHEAST INTO THE CWA...WHILE A WEAK SURFACE TROUGH
EXTENDS FROM THE FURNAS COUNTY AREA NORTHWARD INTO NORTH CENTRAL
NEB. AS EXPECTED...TEMPERATURES HAVE SOARED IN THE SOUTHWESTERLY
FLOW IN THE WAKE OF THE WARM FRONT...WITH A SEASONABLY IMPRESSIVE
MID AFTERNOON TEMPERATURE GRADIENT RANGING FROM THE UPPER 80S-LOW
90S IN NORTH/NORTHEAST ZONES...TO 102-108 IN SEVERAL SOUTHWEST
COUNTIES. WIND DIRECTION IS ALSO SHOWING A RATHER SHARP VARIANCE
ACROSS THE WARM FRONT...TRANSITIONING FROM SOUTHEASTERLY TO
SOUTHWESTERLY AS THE WARM FRONT PASSES...ALONG WITH A NOTICEABLE
DECREASE IN DEWPOINTS. VISIBLE SATELLITE IMAGERY IS SHOWING QUITE
A BIT OF MID LEVEL CLOUD COVER INCREASING OVER THE CWA FROM THE
NORTHWEST...WHILE ALONG THE ADVANCING WARM FRONT AND TRIPLE POINT
AREA...THUS FAR WEAK ISOLATED/SCATTERED SHOWERS/STORMS ARE
DEVELOPING ON THE LEADING EDGE OF A SCATTERED CUMULUS
FIELD...WITH THE BOUNDARY LAYER CUMULUS AREA CLOSELY TIED TO THE
EDGE OF A NORTHEASTWARD ADVANCING PLUME OF STEEP LOW LEVEL LAPSE
RATES. WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA REVEALS THE
CENTER OF THE PRIMARY MID-UPPER RIDGE OVER THE SOUTHERN
PLAINS...WITH THE CWA AND CENTRAL/NORTHERN PLAINS REGION
UNDERNEATH THE SEASONABLY RESPECTABLE WEST-NORTHWEST FLOW ALOFT
ALONG THE PERIPHERY OF THE RIDGE...WITH THE ONLY DISCERNIBLE
SHORTWAVE ON WATER VAPOR IMAGERY ACROSS SD.
STARTING OFF WITH FIRE WEATHER THE NEXT FEW HOURS...IN HINDSIGHT
PROBABLY COULD HAVE/SHOULD HAVE ISSUED A FIRE WEATHER HEADLINE FOR A
HANDFUL OF SOUTHWESTERN COUNTIES AS RELATIVE HUMIDITY VALUES HAVE
CRASHED TO NEAR OR JUST BELOW 20 PERCENT BEHIND THE SURGING WARM
FRONT AND WIND GUSTS HAVE FAIRLY CONSISTENTLY REACHED/TOPPED 25
MPH. HOWEVER...BEING PAST MID AFTERNOON ALREADY...WILL FOREGO
WARNING ISSUANCE AND KEEP ELEVATED FIRE DANGER MENTION IN THE HWO
AND EXTREME FIRE DANGER CATEGORY IN THE GRASSLAND FIRE DANGER
PRODUCT.
TURNING TO THUNDERSTORM CHANCES/SEVERITY...PLENTY OF QUESTIONS
STILL REMAIN REGARDING COVERAGE AND SEVERITY. FOR ONE THING...THE
FAIRLY EXPANSIVE BAND OF MID CLOUDS OVERTAKING MUCH OF THE CWA IS
LIKELY NOT DOING ANY FAVORS FOR HELPING THE CURRENTLY WEAK
CONVECTION MAINLY IN SOUTHWEST ZONES OVERCOME AT LEAST A WEAK
CAPPING INVERSION...WHILE AT THE SAME TIME...HOURLY MESOSCALE
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR SEVERE WITH
1000-2000 J/KG MLCAPE...AND AT LEAST 30KT OF 0-6KM DEEP LAYER
SHEAR...WHICH IS ENOUGH TO GET AT LEAST BRIEF SUPERCELL STRUCTURES
GOING. LEANING ON HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4K
WRF-NMM...ANTICIPATE STORMS TO GRADUALLY INCREASE IN COVERAGE AND
INTENSITY AS THE LATE AFTERNOON/EVENING WEARS ON...ESPECIALLY
ACROSS THE SOUTHERN 2/3 OF THE CWA. HOWEVER...GIVEN CONTINUED
UNCERTAINTY IN ULTIMATE COVERAGE AND DESIRE TO NOT GET RAIN HOPES UP
TOO MUCH IN THIS DROUGHT PATTERN...HAVE OPTED TO LIMIT POPS TO NO
MORE THAN 30 PERCENT/SCATTERED COVERAGE FOR NOW THROUGH 06Z. ANY
STRONG/SEVERE STORMS THAT GET GOING SHOULD PRIMARILY POSE A WIND
THREAT...GIVEN STEEP LOW LEVEL LAPSE RATES AND CONSIDERABLE
SURFACE TEMP-DEWPOINT DEPRESSIONS AND RESULTANT HIGH CLOUD BASES.
HOWEVER...HAIL TO AROUND QUARTER SIZE CANNOT BE RULED OUT
COMPLETELY. ALTHOUGH SPC HAS OFFICIALLY LEFT THE SOUTHWEST 1/3 OR
SO OF THE CWA OUT OF A SLIGHT RISK...FOR LOCAL PRODUCT PURPOSES
FEEL THAT INCLUDING ALL 30 COUNTIES IN A SLIGHT RISK SCENARIO FOR
WIND/HAIL IS THE WAY TO GO. WOULD EXPECT INDIVIDUAL/MULTICELL
UPDRAFTS TO POSSIBLY CONGEAL INTO A BROKEN SOUTH-SOUTHEAST MOVING
LINE AT SOME POINT THIS EVENING ACROSS THE SOUTHERN CWA...POSSIBLY
ENHANCING A LOCALIZED WIND THREAT. AFTER 06Z...INTRODUCED A 20 POP
ACROSS A FEW FAR SOUTHEASTERN COUNTIES TO ACCOUNT FOR THE
POSSIBILITY OF LINGERING OVERNIGHT STORMS ALONG A VEERING LOW
LEVEL JET AXIS...BUT BY THIS TIME ANTICIPATE ANY SEVERE THREAT TO
BE ON THE WANE. TEMP WISE TONIGHT...NUDGED DOWN LOWS A FEW DEGREES
MOST AREAS PER GUIDANCE CONSENSUS...RANGING FROM LOW 60S FAR
NORTHWEST TO AROUND 70 FAR SOUTHEAST.
GETTING INTO THE DAYTIME HOURS TOMORROW...AND STARTING WITH
TEMPERATURES...AM WONDERING JUST HOW WARM IT IS GOING TO GET WITH
NORTHEAST/EASTERLY BREEZES FLOWING INTO THE CWA IN THE FORM A WEAK
BACK DOOR COLD FRONT FLOWING OUT OF A SURFACE HIGH TO THE
NORTHEAST. HOWEVER...WITH 850MB TEMPERATURES STAYING QUITE
TOASTY...IT WON/T TAKE MUCH MIXING TO GET THINGS CLIMBING FAST. AS
A RESULT...ONLY NUDGED DOWN HIGHS AN AVERAGE OF 1-2 DEGREES MOST
AREAS...STILL CALLING FOR MID-UPPER 90S IN MOST NEB ZONES...AND
100-105 IN KS ZONES AND FURNAS COUNTY AREA. ALTHOUGH CONFIDENCE IS
LOW REGARDING DEWPOINT TRENDS...WITH THE NAM SOMEWHAT INEXPLICABLY
CRASHING DEWPOINTS ALL THE WAY INTO THE UPPER 30S IN NORTHERN
AREAS ALTHOUGH THIS SOLUTION WAS NOT FOLLOWED...CURRENT GRIDS
YIELD HEAT INDEX VALUES IN THE 103-105 RANGE ACROSS PARTS OF KS
ZONES...WHICH COULD NECESSITATE HEAT ADVISORY ISSUANCE.
HOWEVER...WITH SOME UNCERTAINTY REMAINING REGARDING THE STRENGTH
OF THE BACK DOOR COLD FRONT ALONG WITH DEWPOINTS...WILL DEFER TO
OVERNIGHT SHIFT FOR POSSIBLE ADVISORY ISSUANCE...AND CONTINUE TO
MENTION HEAT IN THE HAZARDOUS WEATHER OUTLOOK. AS FOR STORM
CHANCES...LEFT THE MORNING HOURS FREE OF RAIN MENTION...ALTHOUGH
SOME ACTIVITY COULD BE FESTERING RATHER CLOSE TO THE FAR SOUTHERN
EDGE OF THE CWA. FOR THE AFTERNOON HOURS...TRIMMED BACK THE AREA
OF SLIGHT POPS TO ONLY AREAS MAINLY SOUTH OF A CAMBRIDGE-SMITH
CENTER LINE...WHERE THE PRIMARY SURFACE FRONT WILL STALL OUT AND
FOCUS A POSSIBLE INSTABILITY AXIS. AT THIS TIME...NOT ANTICIPATING
A SEVERE THREAT DURING THE DAYTIME PERIOD...BUT IN THIS TRICKY
PATTERN WITH ONE SUBTLE SHORTWAVE AFTER ANOTHER MOVING ACROSS THE
TOP OF THE UPPER RIDGE AXIS...THINGS ARE SUBJECT TO CHANGE ON
SOMEWHAT SHORT NOTICE.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. BIGGEST CHALLENGE WILL
BE DETERMINING CHANCES AND TIMING OF ANY PRECIPITATION. ENSEMBLE
MEANS FROM THE ECMWF SEEM THE BEST BET FOR CONSISTENCY. WE BEGIN
THE LONG TERM WITH THE SOUTH CENTRAL PLAINS ANTICYCLONE HEAVILY
INFLUENCING OUR WEATHER...BUT WITH NUMEROUS SHALLOW PERTURBATIONS
ALONG THE PERIPHERY TO THROW UNCERTAINTY INTO THE FORECAST.
UNCERTAINTY ALSO EXISTS FOR WHAT KIND OF SURFACE FEATURES WE MIGHT
HAVE...BUT WE COULD HAVE A FRONT DRAPED ACROSS THE CWA SUNDAY
NIGHT...AS SUGGESTED BY SOME MODELS...THAT COULD BE A FOCUS FOR
ELEVATED CONVECTION...MAINLY ALONG AND JUST NORTH OF THE BOUNDARY.
AN EAST-WEST ORIENTED THETA-E RIDGE IS ADVERTISED TO DRAPE ACROSS
SOUTH CENTRAL NEBRASKA FOR SUNDAY NIGHT...WHICH SUGGESTS THAT
CHANCES OF PRECIPITATION IN THE FORECAST ARE WARRANTED. THERE
COULD BE BOUNDARIES DRAPED ACROSS PARTS OF THE CWA FOR THE BULK OF
THE LONG TERM AS WELL...AS THE FORECAST GETS A LITTLE MUDDLED WITH
POTENTIALLY COMPLICATED SURFACES FEATURES.
THE ANTICYCLONE/RIDGE WILL RETROGRADE SOMEWHAT BY MONDAY...WITH
PERTURBATIONS CONTINUING TO PLAY HAVOC ON ANY CERTAINTY IN THE
FORECAST. THE UPPER LEVEL HIGH WILL CONTINUE TO BE A PROMINENT
FEATURE FOR THE REMAINDER OF THE LONG TERM...HOWEVER. MODELS ARE
KEEPING POTENTIALLY SIGNIFICANT AMOUNTS OF MID-HIGH LEVEL CLOUDINESS
AROUND ON TUESDAY...AND I WILL KNOCK DOWN TEMPERATURES A BIT FROM
THE PREVIOUS FORECAST FOR THIS REASON. WITH THE UPPER LEVEL HIGH IN
PLACE FOR THE REST OF THE WEEK...THIS MEANS MORE ABOVE NORMAL
TEMPERATURES...EVEN WITH ADDITIONAL MID TO UPPER LEVEL CLOUDINESS.
SINCE THE HIGH RETROGRADES A BIT...THIS SHOULD ALLOW A BIT MORE
CHANCES OF PRECIPITATION MORE OFTEN WITH FREQUENT PERTURBATIONS
POSSIBLE. THE ECMWF INDICATES A BIT MORE SIZABLE OF A SHORTWAVE
TROUGH CUTTING THROUGH THE NORTHERN/CENTRAL PLAINS FOR
SATURDAY...WHICH WILL HELP FLATTEN THE RIDGE SOMEWHAT...AND PERHAPS
GIVE A BETTER SHOT AT PRECIPITATION THAN THE LOW CONFIDENCE/LOW
CHANCE PRECIPITATION PATTERN FOR MUCH OF THE LONG TERM. JUDGING BY
THE POTENTIAL STRENGTH OF THE WAVE...THIS COULD BE THE MOST
POTENTIAL FOR SEVERE WEATHER IN THE LONG TERM AS WELL...NOT TO SAY
THERE COULD NOT BE A STRONG STORM WITH ANY CONVECTION THAT MAY FIRE
ALONG THE WAY DURING THE EXTENDED. ALTHOUGH...THE 12Z ECMWF HAS JUST
BACKED OFF OF THE AMPLITUDE OF THE WAVE ON SATURDAY...THIS WAVE
STILL BEARS WATCHING FOR POTENTIAL PRECIPITATION AND PERHAPS STRONG
TO SEVERE WEATHER.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1241 AM CDT FRI JUL 27 2012
.AVIATION...
WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
WEST OF MRR-IML LATE FRIDAY AFTERNOON. THE SHOWERS AND ISOLATED
THUNDERSTORMS WILL THEN SPREAD INTO PARTS OF NORTH CENTRAL TO
SOUTHWEST NEBRASKA AFTER 00Z WITH THE HIGHEST COVERAGE NORTH AND
WEST OF ANW-LBF-OGA. HOWEVER...WITH COVERAGE LESS THAN 20 PERCENT IN
CENTRAL AND SOUTHWEST NEBRASKA AND LESS THAN 40 PERCENT IN NORTH
CENTRAL AND NORTHWEST NEBRASKA...IT WILL NOT BE INCLUDED IN THE
TERMINAL FORECASTS FOR VTN OR LBF. LIGHT AND VARIABLE WINDS
OVERNIGHT BECOMING SOUTHEAST FRIDAY AFTERNOON ON THE BACKSIDE OF THE
SURFACE HIGH AND INCREASING TOWARD SUNSET FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 903 PM CDT THU JUL 26 2012/
UPDATE...
UPDATED TO REMOVE ISOLATED THUNDERSTORMS.
AVIATION...
VISUAL FLIGHT RULES EXPECTED OVER WESTERN NEBRASKA THROUGH FRIDAY AFTERNOON.
PREV DISCUSSION... /ISSUED 621 PM CDT THU JUL 26 2012/
UPDATE...
UPDATED FORECAST TO EXPAND THUNDERSTORM AREA.
PREV DISCUSSION... /ISSUED 406 PM CDT THU JUL 26 2012/
DISCUSSION...
A FAIRLY STRONG COLD FRONT ACROSS SD THIS AFTN IS PROGGED TO DROP
THROUGH SWRN NEB THIS EVENING AND BECOME STATIONARY ALONG THE KS
BORDER FRIDAY MORNING. THE FRONT...MARGINAL INSTABILITY...STRONG
SHEAR...30 TO 40 KTS OF BULK SHEAR RESULTING IN BULK RICHARDSON
NUMBER NEAR 25 AND SFC DEW POINTS IN THE LOWER 50S SUGGEST ISOLATED
HIGH BASED STORM COVERAGE SHOULD ANYTHING FORM. BOTH THE HRRR AND
RAP13 ARE VERY AMBITIOUS SHOWING SCATTERED STORM COVERAGE FROM 20Z
ONWARD.
THE FRONT WILL LIFT NORTH INTO NCNTL NEB FRIDAY AND ACT AS A FOCUS
FOR ISOLATED LATE AFTN AND EVENING HIGH BASED TSTMS GIVEN LOW SFC
DEW POINTS. TEMPS ALONG AND WEST OF HIGHWAY 83 SHOULD RECOVER WITH
HIGHS IN THE MID AND UPPER 90S.
INCREASING LOW LEVEL FLOW...DEEPENING LOW PRESSURE ACROSS THE NRN
HIGH PLAINS AND VERY DEEP MOISTURE ABOVE 700 MB IS EXPECTED TO
PRODUCE A ROUND OF SCATTERED HIGH BASED TSTMS...POSSIBLY PRODUCING
WIND DAMAGE AS THEY MOVE EAST ACROSS THE FCST AREA FRIDAY NIGHT
INTO SATURDAY MORNING. THIS AREA OF STORMS MOVES TO NEAR KOMA BY
12Z SATURDAY AND THE WARM FRONT ADVANCES NORTH AND EAST TO NEAR
KONL/KYKN SATURDAY AFTERNOON. HIGHS SATURDAY SHOULD BE ABLE TO
REACH 100F AS H10-5 THICKNESSES RISE TO NEAR 590 DM. MORE ISOLATED
DIURNALLY DRIVEN HIGH BASED TSTMS ARE EXPECTED TO DEVELOP LATE SATURDAY.
ANOTHER WEAK BACK DOOR COLD FRONT WILL MOVE THROUGH SATURDAY
NIGHT. THIS FRONT WOULD APPEAR TO WASH OUT ACROSS SRN NEB SUNDAY.
BY NOW A HEAT LOW HAS ESTABLISHED ITSELF ACROSS WRN KS/ERN COLO.
THIS LOW COULD STILL PRODUCE TEMPS NEAR 100F AS BOTH THE NAM AND
GEM SHOW H10-5 THICKNESSES APPROACHING 590 DM ACROSS WRN NEB. THE
GENERAL CONSENSUS AMONG THE MODELS WAS FOR ANOTHER UPPER LEVEL
DISTURBANCE TO MOVE THROUGH LATE SUNDAY SUNDAY NIGHT.
MONDAY THROUGH THURSDAY...
THE DROUGHT RIDGE IS FCST BY ALL MODELS TO REMAIN STATIONARY AND
CENTER OVER ERN NM/NW TX. THIS COULD PLACE THE FCST AREA IN THE
RING OF FIRE PROVIDED AMPLE MOISTURE IS AVAILABLE. THE ECM AND GFS
850-300MB MOISTURE SUPPORT THIS BUT FCST QPF IN BOTH MODELS IS
DRY. SO DRY WEATHER IS EXPECTED WITH HIGHS AT LEAST IN THE 90S. H7
TEMPS ARE EXPECTED TO RUN 10C TO 14C WHICH SHOULD PRODUCE UPPER
90S. NOTE THE EXTREME DROUGHT CONDITIONS MAY SUPPORT HIGHS AROUND
100 BUT NOT NEARLY AS WARM AS WE SAW EARLIER THIS MONTH.
FIRE WEATHER...
ALL THUNDERSTORM ACTIVITY WILL BE CLOSELY MONITORED DURING THE
NEXT 7 DAYS FOR SIGNS OF DRY LIGHTNING AND POTENTIAL WILD FIRES.
STORM COVERAGE IS EXPECTED TO BE LESS THAN 25 PERCENT IN ANY ONE
PARTICULAR FIRE WEATHER ZONE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT THU JUL 26 2012
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK
CDFNT CURRENTLY MOVG THROUGH THE OMA/LNK TAF SITES AND WILL CONT TO
THE SOUTH. PRESSURE RISES BEHIND THE FNT WILL KEEP SOME NORTH WIND
UP THROUGH THE NIGHT AND THROUGH THE DAY ON FRIDAY. LITTLE IN THE
WAY OF CLOUD COVER IS EXPECTED THROUGH THE NEXT 24 HOURS...ALTHOUGH
A FEW LATE MRNG/AFTN CU WILL BE POSSIBLE AT OMA /WHICH IS A BIT
CLOSER TO THE LOW LEVEL MOIST CYCLONIC FLOW OVER IA/MN/ BUT WL LEAVE
ALL THE TAFS CLR ATTM THRU 06Z SAT.
BOUSTEAD
&&
.DISCUSSION...
SMALL CHANCE FOR PRECIPITATION TONIGHT...THEN THUNDERSTORM CHANCES
FRIDAY NIGHT THROUGH MONDAY...ARE THE PRIMARY FORECAST CONCERNS.
SECONDARY COOL FRONT WAS DROPPING THROUGH THE CWA THIS AFTERNOON.
TEMPERATURES WERE SIMILAR ON BOTH SIDES OF THE BOUNDARY...BUT DEW
POINTS DRIED CONSIDERABLY BEHIND THE FRONT. DEW POINTS WERE IN THE
THE 50S IN NORTHEAST NEBRASKA AS OF 2 PM...WHILE SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA HAD DEW POINTS BETWEEN 65 AND 70. INSTABILITY
WAS INCREASING IN THIS AREA WITH MOST UNSTABLE CAPE VALUES TOPPING
3000 J/KG. LOW LEVEL CONVERGENCE WAS RATHER WEEK AS WINDS ONLY
TURNED FROM WEST TO NORTHWEST AHEAD AND BEHIND FRONT. AND MID
LEVEL LAPSE RATES WERE RATHER TIMID AS WELL. STILL CUMULUS FIELD
WAS BUBBLING UP IN CYCLONIC FLOW IN EAST CENTRAL NEBRASKA AND WEST
CENTRAL IOWA. NAM...GFS AND HRRR ALL SUGGEST SOME CONVECTION WILL
FIRE IN THE UNSTABLE AIR OVER SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA LATE THIS AFTERNOON AND EVENING. GIVEN INSTABILITY AND WEAK
CONVERGENCE ALONG FRONT...PLUS THE FACT THAT RETURNS ARE SHOWING
UP ON RADAR...WILL INSERT ISOLATED STORMS THIS AFTERNOON AND
EVENING IN THOSE AREAS.
STORMS SHOULD MOVE OUT OR DISSIPATE RATHER QUICKLY BY
SUNSET...LEAVING MOSTLY CLEAR SKIES AND DIMINISHING WINDS AS
SURFACE HIGH PRESSURE SETTLES IN OVERNIGHT. THAT HIGH AND A
REDUCTION IN 850 TEMPS BY 5C OR SO WILL LEAD TO COOLER
TEMPERATURES FRIDAY. HAVE HIGHS FROM THE MIDDLE 80S NORTH TO NEAR
90 SOUTH FRIDAY AFTERNOON WITH LIGHT NORTH OR NORTHEAST WINDS.
AS THE HIGH SHIFTS EAST FRIDAY NIGHT...RETURN FLOW BEGINS AS
SHORTWAVE MOVES OFF THE HIGH PLAINS INTO THE REGION. MODELS HAVE
BEEN ADVERTISING THIS THE LAST SEVERAL DAYS...AND ARE NOW CONVERGING
ON A TRACK THROUGH SOUTH DAKOTA AND INTO SOUTHEAST SOUTH DAKOTA BY
12Z SATURDAY. THIS WILL SHIFT AXIS OF ASSOCIATED PRECIPITATION NORTH
OF OUR CURRENT FORECAST...WITH HIGHEST POPS ALONG THE SOUTH DAKOTA
BORDER. WILL MAINTAIN SMALL POPS SOUTHWARD AT LEAST TO INTERSTATE 80
LATE FRIDAY NIGHT AND SATURDAY MORNING WHERE HIGHER THETA-E AIR WILL
RIDE NORTH. AREA SHOULD LIFT TO THE NORTHEAST SATURDAY AFTERNOON AND
WILL MAINTAIN SMALL POPS IN OUR FAR NORTHEAST THEN.
A SIMILAR SITUATION WILL OCCUR SATURDAY NIGHT INTO SUNDAY AS ANOTHER
SHORTWAVE ROLLS THROUGH THE NORTHERN PLAINS. BOTH GFS AND ECMWF SHOW
THIS WAVE A BIT FARTHER NORTH THAN FRIDAY NIGHT WAVE...BUT
MOISTURE...LOW LEVEL JET AND ELEVATED INSTABILITY WILL ALL BE MORE
CONDUCIVE FOR SCATTERED OVERNIGHT CONVECTION. THUS WILL KEEP OUR
SMALL POPS FOR MOST OF THE CWA WITH HIGHEST CHANCES AGAIN IN THE
NORTH AND NORTHEAST.
SURFACE FRONT WILL TRAIL THIS SECOND WAVE AND SETTLE ACROSS THE CWA
SUNDAY NIGHT AND MONDAY. GFS AND ECMWF TRIGGER PRECIPITATION ALONG
THIS BOUNDARY AS YET ANOTHER SHORTWAVE DROPS THROUGH NORTHWEST FLOW
ALOFT...BUT EACH MODEL HAS A SLIGHTLY DIFFERENT TRACK.
WILL KEEP OUR DRY AND WARMER FORECAST GOING THROUGH MID WEEK AS
UPPER RIDGE TRIES TO BUILD BACK INTO THE REGION. MODELS ARE A LITTLE
LESS BULLISH ON BRINGING THIS INTO THE PLAINS...POSSIBLY ALLOWING
MORE SHORTWAVES TO DROP INTO THE REGION BRINGING SPORADIC PRECIP
CHANCES.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
842 PM CDT SAT JUL 28 2012
.DISCUSSION...
EVENING UPDATE WILL ADDRESS POPS AND TEMPERATURES. CURRENT
MESOSCALE ANALYSIS INDICATING EROSION OF IN WITHIN AND EAST OF
SOUTHERN VALLEY...WHERE RAIN SHOWERS ARE SPREADING EASTWARD. ALSO
HAVE COMPLEX GENERATING NEAR SEVERE WINDS OVER MINOT...ADVECTING
SOUTHEAST. WILL BUMP UP POPS FOR SOUTHEASTERN NORTH DAKOTA AND
WEST CENTRAL MN FROM 03 TO 06Z. VERY LITTLE 0-6 KM SHEAR SO SEVERE
IS NOT A THREAT WITH EXCEPTION OF FAR WESTERN ZONES. WEST COMPLEX
APPEARS THAT IT WILL MISS WESTERN ZONES AND MOVE MORE INTO WEST
CENTRAL ZONES IF THEY STAY TOGETHER THAT LONG. WILL BUMP POPS UP
TO CHANCE CATEGORY FOR UPPER SHEYENNE BASIN AREA. TEMPS ARE COOLEST
IN RAIN IMPACTED AREAS OF SOUTHEAST NORTH DAKOTA. ALSO USED HRRR
TO UPDATE HOURLY TEMPS AS HRRR HAS MUCH BETTER HANDLE ON CURRENT
TRENDS THAN PREV FCST CURVE.
&&
.AVIATION...
VFR CIGS WITH POTENTIAL FOR TSTM ACTIVITY OVER NEXT THREE HOURS IN
FAR AREA. MOST LIKELY TO SEE LIGHT RAIN BUT THUNDER TO THE WEST OF
THE AIRPORT A POSSIBILITY. CONVECTION SHOULD DIE DOWN AFTER
MIDNIGHT WITH MOSTLY MID CLOUD REMAINING THROUGH THE NIGHT.
&&
.PREV DISCUSSION... /ISSUED 336 PM CDT SAT JUL 28 2012/
SHORT TERM (TONIGHT THROUGH TUESDAY EVENING)...
15Z SREF AND 18Z NAM GUIDANCE BOTH SUGGEST THAT EXISTING CONVECTIVE
CLUSTER JUST SOUTH OF BIS WILL CONTINUE ON AN EASTERLY TRACK THROUGH
EARLY EVENING... GENERALLY BETWEEN I-94 AND THE SD BORDER. THREAT
FOR MEASUREABLE PRECIPITATION IS HIGHEST THROUGH RANSON...SARGENT
AND RICHLAND COUNTIES... WITH THE CONVECTION EXPECTED TO WEAKEN
CONSIDERABLY WITH SUNSET.
A SECOND AREA OF STRONG CONVECTION /ASSOCIATED WITH A WEAK MID LVL
SHRTWV TROF/ IS MOVING THROUGH SERN SASK ATTM... AND SHOULD PUSH
ACROSS THE NORTHERN TIER COUNTIES ALG AND NORTH OF THE HWY 2
CORRIDOR FROM LATE EVENING INTO THE OVERNIGHT HOURS. CURRENT
GUIDANCE SUGGESTS SOME RESIDUAL CONVECTION WILL PERSIST ACROSS THE
LAKE OF THE WOODS AREA AND INTO NERN MN THROUGH MID MORNING. MIDDAY
SUNDAY SHOULD SEE FAIR SKIES AND BREAK IN CONVECTION AS WEAK H5
RIDGING TRANSITS THE AREA... BUT A SECOND SHRTWV TROF IS EXPECTED BY
LATE AFTERNOON... WITH CONVECTION BUILDING FROM ERN ND INTO NW AND
WCNTRL MN BY EARLY EVENING.
MONDAY MORNING INTO TUESDAY... CLEARING SKIES AND BUILDING SFC TO H5
RIDGING SHOULD FOLLOW THE FRONTAL PASSAGE FROM SUNDAY EVENING.
ALLOWING FOR FAIR SKIES AND STEADILY WARMING TEMPS... BACK ABOVE
SEASONAL NORMALS.
LONG TERM (TUE NITE THROUGH SATURDAY)...
OUR GUIDANCE REMAINS IN GENERAL AGREEMENT STARTING WITH DEPARTING
HIGH PRESSURE AS EXTENDED PERIOD COMMENCES TUESDAY EVENING.
RETURN FLOW THEN DEVELOPS WHICH IN TURN SETS THE STAGE FOR THE NEXT
SIGNIFICANT THREAT FOR SHOWERS AND STORMS ON WEDNESDAY. BEST CHANCES
FOR DRY WEATHER COME THURSDAY...BEFORE NEXT WAVE APPROACHES FRIDAY.
ECMWF IS MORE TIMID WITH FRIDAY SYSTEM OFFERING LITTLE IN WAY OF A
SURFACE SYSTEM WHILE THE GFS PAIRS UPPER DYNAMICS WITH MORE DISTINCT
CANADIAN SURFACE LOW PRESSURE AND COLD FRONT TRAILING SOUTHWARD
THROUGH THE NORTHERN PLAINS. TEMPERATURES WILL DROP BEHIND THE
FRONT...LEAVING A COOLER SATURDAY WITH HIGHS IN THE 70S.
AVIATION...
ALTHOUGH OVERNIGHT CONVECTION IS POSSIBLE...COVERAGE SHOULD BE
ISOLATED ENOUGH TO NOT WARRANT A MENTION IN TAFS. OTHERWISE VFR WITH
STEADY STATE SOUTH TO SOUTHWEST WINDS AVERAGING ABOUT 10 KTS THROUGH
SUNDAY MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
347 PM CDT FRI JUL 27 2012
.SHORT TERM...NOW THROUGH SATURDAY NIGHT...
MIDDLE LEVEL SHORTWAVES EMBEDDED WITHIN THE CYCLONIC FLOW OVER
NORTHWESTERN CONUS WILL OCCASIONALLY PHASE WITH MIDDLE LEVEL
SHORTWAVES REVOLVING AROUND THE DOMINANT SUBTROPICAL HIGH OVER
CENTRAL CONUS AS THEY PASS THROUGH THE NORTHERN HIGH PLAINS. THIS
PHASING SHOULD INTRODUCE BROAD SCALE UPWARD VERTICAL MOTION
SUFFICIENT TO ERODE CAPPING ASSOCIATED WITH THE SUBTROPICAL HIGH
SUBSIDENCE.
THE MAIN FORECAST PROBLEM TODAY IS DECIDING WHEN THE BEST PHASING
WILL OCCUR AND INTRODUCING HIGHER PRECIPITATION CHANCES AT THOSE
TIMES. THE PRECIPITATION CHANCES REPRESENT A BLEND OF THE 15 UTC
SREF MEAN AND 12 UTC ECMWF/GFS/GEM GLOBAL AND RECENT HRRR RUNS.
ABOVE AVERAGE TEMPERATURES SHOULD RETURN INTO THE FORECAST THIS
WEEKEND...AND THERE IS NO INDICATION THAT THE CENTRAL U.S. RIDGE
WILL MOVE OR WEAKEN. THUS...EXPECT THE ACTIVE PATTERN TO CONTINUE
AS IMPULSES TRAVEL THROUGH THE NORTHERN PLAINS.
.LONG TERM...SUNDAY THROUGH FRIDAY...
WESTERN ROCKIES AND HIGH PLAINS RIDGE REMAINS PERSISTENT THROUGH THE
EXTENDED PERIODS WITH PERIODIC SHORTWAVES TOPPING THE RIDGE AND
BRINGING EPISODES OF THUNDERSTORMS TO THE FORECAST AREA. THE FIRST
SYSTEM IN THE EXTENDED WILL MOVE ACROSS THE NORTHERN PLAINS SATURDAY
NIGHT/SUNDAY AT THE BEGINNING OF THE PERIOD WITH A WEAK SURFACE
TROUGH TRAVERSING THE STATE. HAVE RAISED CHANCES DAYTIME SUNDAY WITH
A BIT MORE CONFIDENCE ON TIMING. THE NEXT SYSTEM APPROACHES ON
TUESDAY INTO WEDNESDAY/THURSDAY...WITH A MORE SIGNIFICANT
LOW/SHORTWAVE DEPICTED MOVING THROUGH THE FORECAST AREA ON FRIDAY.
TIMING OF SHORT WAVES WILL BE DIFFICULT AND LOW POPS CHANCES
GENERALLY IN MUCH OF THE EXTENDED PERIODS UNTIL THE END OF NEXT
WEEK.
TEMPERATURES SHOULD BE SLIGHTLY ABOVE AVERAGE WITH HIGHS MAINLY IN
THE UPPER 80S TO LOWER 90S AND LOWS IN THE 60S.
&&
.AVIATION...
VFR CONDITIONS TO CONTINUE THIS AFTERNOON ALL TAF SITES.
THE FIRST IN A SERIES OF LOWS IS FORECAST TO MOVE EASTWARD FROM
CENTRAL MONTANA/WYOMING AND REACH SOUTHWESTERN NORTH DAKOTA AROUND
00Z...AND SPREAD NORTH AND EAST ACROSS CENTRAL NORTH DAKOTA
AROUND/AFTER 06Z. ADDED MENTION OF VCTS TO KDIK AT 03Z AND AT KISN
AT 06Z...BUT LEFT MENTION OUT OF KBIS/KMOT DUE TO SCATTERED/ISOLATED
NATURE OF CONVECTION BY THE TIME THE IMPULSE WOULD REACH CENTRAL
NORTH DAKOTA. LATER TAF ISSUANCE MAY REFINE COVERAGE AND TIMING OF
CONVECTION FOR KBIS/KMOT/KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION...JV
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1057 AM CDT FRI JUL 27 2012
.DISCUSSION...
HIGH PRESSURE NR DEVILS LAKE TO JAMESTOWN TO ABERDEEN LINE AT
15Z WITH LIGHT WINDS OVER THE FCST AREA. AREA OF LOW LEVEL
MOISTURE AND LOWER CLOUDS WHICH IS PICKED UP WELL BY 925 MB RH
FROM RAP MODEL HANGS ON FROM GRAND RAPIDS TO BEMIDJI MN SOUTHWARD.
THIS MODEL SHOWS SOME DECREASE IN RH DURING THE AFTN SO DO
EXPECTED CONTINUED SLOW BREAKUP INTO A BROKEN CU FIELD AS EVIDENT
BY CURRENT VSBL SATELLITE PIX. WILL INCREASE SKY COVER IN THAT
BJI-PKD-ADC AREA THRU 21Z TO ACCOUNT FOR BROKEN SKY CONDITIONS
THEN HAVE BETTER CLEARING LATE AFTN/EARLY EVE. LOWERED HIGH TEMPS
A FEW DEGREES IN THIS BAND WITH LOW TO MID 70S LIKELY
THERE...WHILE NR 80 MOST OTHER PLACES WHERE SUNSHINE MORE
PREVELENT. SOME CU STARTING TO FORM AS WELL ALONG THE WESTERN EDGE
OF THE RED RIVER VALLEY FROM MORDEN MANITOBA TO CAVALIER TO
LARIMORE ND DOWN TO WEST OF FARGO. SO EXPECT SOME CU EAST OF HIGH
PRESSURE RIDGE THIS AFTN....BUT SHOULD DISSIPATE AS WARMER AIR
ALOFT MOVES AS HIGH MOVES OVERHEAD AND MOVES EAST.
&&
.AVIATION...
BEMIDJI-PARK RAPIDS-WADENA AREA TO STAY IN BROKEN MVFR CU THRU
21Z...THEN SLOW CLEARING. OTHER TAF SITES VFR WITH SOME CU PSBL.
LIGHT WINDS ALL AREAS.
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT FRI JUL 27 2012/
SHORT TERM (TODAY-SUNDAY NIGHT)...MAIN CONCERNS WILL BE
TEMPERATURES AND THEN THUNDER CHANCES LATER IN THE PERIOD. 00Z
MODELS IN DECENT AGREEMENT WITH SYNOPTIC FEATURES AND WILL USE A
BLEND FOR DETAILS.
CURRENT CLOUD COVER ACROSS THE SOUTHEAST FA SHOULD CONTINUE TO
SLIDE TO THE SOUTH/SOUTHEAST.
SURFACE HIGH PRESSURE WILL MOVE THROUGH THE REGION TODAY AND
TONIGHT WITH RETURN FLOW SETTING UP ON SATURDAY. SOUTHERLY LOW
LEVEL FLOW WILL CONTINUE INTO SUNDAY BEFORE A BOUNDARY AND DRIER
AIRMASS MOVES INTO THE REGION SUNDAY NIGHT. WATER VAPOR IMAGERY
INDICATES MULTIPLE SHORTWAVES UPSTREAM THAT COULD AFFECT THE
REGION OVER THE NEXT FEW DAYS. TODAY WILL BE DRY AS ACTIVITY
SHOULD DISSIPATE AS IT APPROACHES THE LOW-LEVEL RIDGE. THERE WILL
BE LOW-END THUNDER CHANCES THROUGH THE WEEKEND...ALTHOUGH BEST
CHANCES APPEAR TO BE SUNDAY AFTERNOON/EVENING ACROSS THE NORTHERN
FA AS SFC BOUNDARY COINCIDES WITH PEAK HEATING AND INCREASED
MOISTURE. DEEP LAYER SHEAR WOULD BE SUFFICIENT FOR A STRONGER
STORM OR TWO IF CONDITIONS SET UP FAVORABLY.
TEMPERATURES WILL WARM A BIT EACH DAY...NEAR NORMAL TO SLIGHT
ABOVE NORMAL BY THE END OF THE PERIOD.
LONG TERM (MONDAY-THURSDAY)...REGION WILL REMAIN IN ELEVATED NW
FLOW PATTERN THROUGH THE LONG RANGE PERIOD. MAIN CHALLENGE WILL BE
TIMING OF WEAK IMPULSES ROUNDING RIDGE PROVIDING LIGHT PCPN
CHANCES. AS EXPECTED MODELS DIFFER ON TIMING OF ANY WEAK FEATURES
MAKING ANY FINE TUNING OF POPS DIFFICULT. FOR THIS WILL MAINTAIN
LOW POPS ON AND OFF THROUGH THE PERIOD. TEMPERATURES WILL BE ABOVE
SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
758 PM EDT SAT JUL 28 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTHWEST...PROVIDING DRY CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL WARM EARLY IN THE WEEK...WITH LOW PRESSURE BRINGING A CHANCE
OF PRECIPITATION MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
PRIMARY CONCERN FOR THE NEAR TERM IS THE CHANCE OF SHOWERS IN THE
EASTERN HALF OF THE CWA OVER THE NEXT FEW HOURS. A WEAK FRONT HAS
MOVED THROUGH MOST OF THE CWA...SWITCHING WINDS TO THE NORTH AND
BRINGING GUSTS UP TO THE 15-20 KNOT RANGE IN SOME LOCATIONS.
NEBULOUS SURFACE LOW PRESSURE OVER WESTERN PENNSYLVANIA WILL MOVE
FURTHER AWAY...AS A MID LEVEL SHORTWAVE HEADS SOUTHEAST INTO THE
MID-ATLANTIC. FORCING FOR SHOWERS (AND THE SLIM CHANCE OF A FEW
RUMBLES) WILL THUS BE LARGELY DIMINISHING OVER THE CWA THROUGH THE
EVENING HOURS...WHICH SHOULD COMBINE WITH THE DIURNAL CYCLE TO
ALLOW FOR A GRADUAL DIMINISHING IN POPS THROUGH AND JUST AFTER
00Z. HIGH-RES MODELS (RECENT HRRR RUNS FOR EXAMPLE) SHOW SOME
ENHANCEMENT CLOSER TO 00Z...AND A BIT MORE WESTWARD OF ACTIVITY
THAN THE FORECAST WILL INDICATE.
WITH LIGHT WINDS AND CLEAR SKIES...THERE DOES APPEAR TO BE SOME
FOG POTENTIAL OVERNIGHT. BOUNDARY LAYER MOISTURE IS NOT ESPECIALLY
HIGH...BUT SHOULD BE HIGH ENOUGH TO AT LEAST PROMOTE FOG IN THE
VALLEYS AND LOW LOCATIONS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
HIGH PRESSURE WILL EXTEND FROM THE GREAT LAKES INTO THE OHIO
VALLEY ON SUNDAY...PLACING THE CWA IN AN AREA OF WEAK WIND FLOW.
THE AIR MASS WILL NOT BE SUBSTANTIALLY DIFFERENT FROM THE ONE OVER
THE REGION TODAY...THOUGH SLIGHTLY DRIER. WITH A DECENT BIT MORE
SUN EXPECTED THAN TODAY...WILL CONTINUE WITH A TEMPERATURE
FORECAST ABOUT 5-7 DEGREES WARMER THAN TODAY.
MOST OF THE MODELS ARE IN AGREEMENT ON A WEAK AREA OF LOW PRESSURE
MOVING FROM THE MIDDLE MISSISSIPPI VALLEY INTO THE SOUTH ON MONDAY
AND INTO MONDAY NIGHT. THE 12Z GFS IS ADVERTISING AN UNSUPPORTED
SOLUTION WITH A SURFACE LOW MOVING THROUGH THE SOUTHERN GREAT
LAKES INSTEAD. WILL SIDE WITH THE CONSENSUS (WHICH INCLUDES THE
06Z GFS) AND KEEP THE FORECAST IMPACTS FOR MONDAY LESS
SUBSTANTIAL. BUILDING INSTABILITY WITH WEAK FORCING WILL SUPPORT
CHANCE POPS IN THE FAR SOUTHWEST...AND SLIGHT CHANCE FOR ABOUT THE
REST OF THE SOUTHWESTERN HALF OF THE CWA.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
HAVE TAKEN A BLEND OF NCEP/HPC AND THE 00Z ECMWF FOR THE EXTENDED
FORECAST AS THEY OFFER THE BEST SOLUTION AND HAVE CONTINUITY.
A WEAK BOUNDARY IS FORECAST TO SLIDE INTO THE REGION AND WITH
DISTURBANCES DROPPING DOWN IN NORTHWEST FLOW...IT APPEARS THAT THERE
WILL BE AN ENHANCED CHANCE OF PRECIPITATION TUESDAY INTO TUESDAY
NIGHT. THAT MAY LINGER INTO WEDNESDAY ALTHOUGH THERE IS MORE
UNCERTAINTY BY THAT TIME. LOOKS LIKE A SURFACE RIDGE WILL MOVE IN
FOR THURSDAY. BUT THERE IS MODEST AGREEMENT IN THE MODELS THAT A
MORE ROBUST SHORT WAVE WILL MOVE INTO THE AREA THURSDAY NIGHT AND
FRIDAY WHICH WOULD BRING ANOTHER CHANCE OF SHOWERS AND
THUNDERSTORMS. THIS FEATURE WILL PASS BY TO THE EAST FRIDAY NIGHT
AND SATURDAY WITH PERHAPS A WEAK SFC BOUNDARY LINGERING ACROSS THE
SRN ZONES ON SATURDAY.
TEMPERATURES ON A WHOLE SHOULD AVERAGE ABOVE NORMAL THROUGH THE
PERIOD. HOW FAR ABOVE NORMAL WILL DEPEND ON CLOUD COVER AND
PRECIPITATION COVERAGE.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
DIMINISHING CU FIELD WILL YIELD SKC TONIGHT. WITH PEAKS OF SUN
TODAY...AND BOUNDARY LAYER NOT AS MOIST AS LAST NIGHT IN THE
WEST...AM NOT ANTICIPATING THE PERSISTENT LIFR VSBYS/CIGS AS THIS
MORNING. STILL SOME LIFR EXPECTED NEAR KLUK AND POSSIBILITY OF IFR
AT KCVG/KILN IN THE 10-12Z TIMEFRAME. OTHER LOCATIONS POSSIBILITY OF
MVFR VSBYS. AS UPR LOW CONTINUES TO ROTATE ENE...WEAK HIGH
PRESSURE WILL BUILD INTO AREA ON SUNDAY. JUST SOME SCT VFR CU
EXPECTED.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...JDR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
245 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND
EVENING. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE NORTHWEST
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPR LVL S/WV LOCATED OVER THE WRN GREAT LAKES THIS MORNING WILL
PIVOT SE ACRS THE REGION LATE THIS AFTN AND OVERNIGHT. AN AREA OF
WEAK LOW PRESSURE AND A SFC COLD FRONT WILL ACCOMPANY THIS FEATURE
AS THEY SLOWLY MOVE SOUTHEAST THROUGH THE REGION OVERNIGHT. THE
COMBINATION OF THESE FEATURES WILL INTERACT WITH A MOIST AND
UNSTABLE AIRMASS THIS AFTERNOON AND EVENING...RESULTING IN
CONVECTIVE DEVELOPMENT FROM EARLY AFTERNOON INTO THE EVENING
HOURS. LATEST HRRR AND NAM SUGGEST THAT CONVECTION WILL GET GOING
ACRS NRN AND CENTRAL INDIANA EARLY THIS AFTERNOON...AND SHOULD
PROPAGATE SE THROUGH OUR AREA THIS AFTERNOON INTO THIS EVENING.
WITH BULK SHEAR IN THE 25 TO 35 KNOT RANGE...STORMS SHOULD EXHIBIT
SOME ORGANIZATION WITH MULTICELLS PERHAPS MERGING INTO LINEAR
BOWING SEGMENTS. IN ADDITION...WITH THE SFC LOW APPROACHING OUR NW
CWFA...THERE WILL BE SOME DIRECTIONAL SHEAR THAT MAY CAUSE A FEW
STORMS TO ROTATE. AS A RESULT OF ALL THESE FACTORS...HAVE GONE
WITH LIKELY POPS THIS AFTERNOON AND HAVE PLACED SEVERE WORDING IN
THE FORECAST. MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS
WITH SEVERE HAIL THE SECONDARY THREAT. AN ISOLATED TORNADO CAN NOT
BE RULED OUT...ESPECIALLY ACRS THE NWRN CWFA. ALTHOUGH STORMS WILL
HAVE SOME MOTION 20 TO 30 MPH AND RAINFALL RATES WILL NOT BE AS
HIGH AS YESTERDAY...OUR SE CWFA RECEIVED SUBSTANTIAL RAINFALL
AMOUNTS IN THE 3 TO 5 INCHES RAIN OVER THE LAST 24 HOURS. THIS HAS
RESULTED IN MOIST IF NOT NEARLY SATURATED SOILS IN THESE LOCALES.
1 HOUR FFG SUBSEQUENTLY ARE RANGING ANY WHERE BETWEEN A HALF INCH
TO AN INCH. GIVEN THIS SETUP...ANY STORMS THAT FORM TODAY...AND IF
THEY MOVE OVER THE SAME AREAS IN THE SE CWFA...THIS WILL LIKELY
RESULT IN AN INCREASED FLOOD THREAT...WITH THE POTENTIAL FOR FLASH
FLOODING. HAVE ISSUES A FLASH FLOOD WATCH FOR THE SE CWFA IN
EFFECT FROM 18Z THIS AFTN TO 08Z EARLY SATURDAY MORNING.
AS FOR TEMPERATURES AND DEWPOINTS...IT WILL BE ANOTHER VERY WARM
TO LOCALLY HOT DAY WITH HIGHS GENERALLY IN THE UPPER 80S TO THE
LOWER 90S AND DEWPOINTS IN THE MID 60S TO AROUND 70. THIS SHOULD
KEEP HEAT INDICES IN THE MID TO UPPER 90S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING INTO THE
EVENING ACROSS THE REGION PARTICULARLY IN THE EAST BEFORE MOVING
OFF AS THE COLD FRONT CONTINUES TO PROGRESS EASTWARD. INCREASED
LOW LEVEL MOISTURE AND WEAK COLD ADVECTION BEHIND THE FRONT SHOULD
RESULT IN THE DEVELOPMENT OF LOW CLOUDS THAT WILL LAST WELL INTO
SATURDAY MORNING. COULD STILL SEE A FEW SHOWERS AND THUNDERSTORMS
DEVELOP ON SATURDAY PRIMARILY IN THE NORTHERN COUNTIES WITH
HEATING AND A WEAK DISTURBANCE DROPPING INTO THE UPPER TROUGH. AS
HIGH PRESSURE BUILDS OVER THE AREA SATURDAY NIGHT AND SUNDAY...
CONDITIONS WILL BE QUIESCENT.
FOLLOWING RECENT TRENDS HAVE PATTERNED TEMPERATURE FORECAST NEAR
OR SLIGHTLY ABOVE WARMER MOS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE WEEK. THIS PATTERN
IS CONDUCIVE TO CONVECTIVE DEVELOPMENT AS DISTURBANCES DROP
SOUTHEAST. HOWEVER THESE DISTURBANCES ARE OFTEN DIFFICULT TO TRACK
AND TIME. AT THIS POINT HAVE INCLUDED LOW CHANCE POPS MAINLY
DURING THE DAYTIME PERIODS. TEMPERATURES WILL REMAIN ABOVE NORMAL.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL DISTURBANCE OVER THE WESTERN GREAT LAKES THIS
AFTERNOON WILL PIVOT SE ACRS THE REMAINDER OF THE GREAT LAKES TONIGHT
AND SATURDAY. THIS WILL SLOWLY PUSH A WEAK AREA OF LOW PRESSURE
AND ASSOCIATED COLD FRONT SOUTHEAST THROUGH THE REGION. THE
APPROACH OF THIS DISTURBANCE AND PREFRONTAL CONVERGENCE AHEAD OF
THE FRONT WILL TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS ACRS
THE AREA EARLY THIS AFTN. MODELS SUGGEST THAT MULTICELLULAR
THUNDERSTORMS COULD CONGEAL INTO BOWING SEGMENTS WITH POSSIBLE TWO
ROUND OF CONVECTION MOVING OVER THE REGION. AS SUCH...BELIEVE
THUNDERSTORM CHANCES ARE HIGH ENOUGH TO WARRANT AT ALL TAF SITES.
HOWEVER...EXACT TIMING IS STILL DIFFICULT AT THIS POINT AND HAVE
THUS GONE WITH A PREDOMINANT VCTS WITH TEMPO MVFR AND THUNDER.
WILL AMENDMENT TAFS ACCORDINGLY FOR WIND AND/OR HAIL PER RADAR
OBSERVATIONS.
FOR THE OVERNIGHT HOURS...CONVECTION SHOULD PUSH TO THE
EAST/SOUTHEAST THIS EVENING. STILL CAN NOT RULE OUT A SHOWER OR
STORM OVERNIGHT WITH THE DISTURBANCE STILL IN THE REGION...BUT
CHANCES ARE LOW ENOUGH TO NOT MENTION ATTM. OF GREATER CONCERN
WILL BE LOW LEVEL MOISTURE ADVECTING SOUTH AROUND WEAK LOW
PRESSURE/COLD FRONT. THIS MOISTURE...COMBINED WITH WEAK COLD AIR
ADVECTION...HAS THE POTENTIAL TO REALIZE ITSELF AS A STRATUS DECK
LATE TONIGHT INTO SATURDAY MORNING. SOME MVFR/IFR VSBYS WILL BE
POSSIBLE AS WELL AND HOW LOW THESE BECOME WILL DEPEND ON HOW FAST
MID LVL CLOUDS EXIT THE REGION BEFORE LOW STRATUS FORMS. HAVE GONE
WITH IFR CIGS AND MVFR/IFR VSBYS ATTM.
ON SATURDAY...LOW LEVEL MOISTURE/STRATUS SHOULD LIFT INTO VFR
CUMULUS AND/OR MODERATE CUMULUS BY SATURDAY AFTERNOON WHILE VSBYS
WILL IMPROVE TO VFR AS WELL. CAN NOT RULE OUT A POP UP SHOWER OR
STORM ACRS THE ERN TAF SITES...BUT THEN AGAIN...IT IS TOO LOW TO
BE CONCERNED ABOUT ATTM.
UNDER A NW FLOW ALOFT...SURFACE HIGH PRESSURE IS FORECAST TO BUILD
SOUTHEAST INTO THE GREAT LAKES AND OHIO VALLEY SATURDAY NIGHT INTO
SUNDAY.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ079>082-088.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ098>100.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...
LONG TERM...
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1148 AM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND
EVENING. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE NORTHWEST
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPR LVL S/WV LOCATED OVER THE WRN GREAT LAKES THIS MORNING WILL
PIVOT SE ACRS THE REGION LATE THIS AFTN AND OVERNIGHT. AN AREA OF
WEAK LOW PRESSURE AND A SFC COLD FRONT WILL ACCOMPANY THIS FEATURE
AS THEY SLOWLY MOVE SOUTHEAST THROUGH THE REGION OVERNIGHT. THE
COMBINATION OF THESE FEATURES WILL INTERACT WITH A MOIST AND
UNSTABLE AIRMASS THIS AFTERNOON AND EVENING...RESULTING IN
CONVECTIVE DEVELOPMENT FROM EARLY AFTERNOON INTO THE EVENING
HOURS. LATEST HRRR AND NAM SUGGEST THAT CONVECTION WILL GET GOING
ACRS NRN AND CENTRAL INDIANA EARLY THIS AFTERNOON...AND SHOULD
PROPAGATE SE THROUGH OUR AREA THIS AFTERNOON INTO THIS EVENING.
WITH BULK SHEAR IN THE 25 TO 35 KNOT RANGE...STORMS SHOULD EXHIBIT
SOME ORGANIZATION WITH MULTICELLS PERHAPS MERGING INTO LINEAR
BOWING SEGMENTS. IN ADDITION...WITH THE SFC LOW APPROACHING OUR NW
CWFA...THERE WILL BE SOME DIRECTIONAL SHEAR THAT MAY CAUSE A FEW
STORMS TO ROTATE. AS A RESULT OF ALL THESE FACTORS...HAVE GONE
WITH LIKELY POPS THIS AFTERNOON AND HAVE PLACED SEVERE WORDING IN
THE FORECAST. MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS
WITH SEVERE HAIL THE SECONDARY THREAT. AN ISOLATED TORNADO CAN NOT
BE RULED OUT...ESPECIALLY ACRS THE NWRN CWFA. ALTHOUGH STORMS WILL
HAVE SOME MOTION 20 TO 30 MPH AND RAINFALL RATES WILL NOT BE AS
HIGH AS YESTERDAY...OUR SE CWFA RECEIVED SUBSTANTIAL RAINFALL
AMOUNTS IN THE 3 TO 5 INCHES RAIN OVER THE LAST 24 HOURS. THIS HAS
RESULTED IN MOIST IF NOT NEARLY SATURATED SOILS IN THESE LOCALES.
1 HOUR FFG SUBSEQUENTLY ARE RANGING ANY WHERE BETWEEN A HALF INCH
TO AN INCH. GIVEN THIS SETUP...ANY STORMS THAT FORM TODAY...AND IF
THEY MOVE OVER THE SAME AREAS IN THE SE CWFA...THIS WILL LIKELY
RESULT IN AN INCREASED FLOOD THREAT...WITH THE POTENTIAL FOR FLASH
FLOODING. HAVE ISSUES A FLASH FLOOD WATCH FOR THE SE CWFA IN
EFFECT FROM 18Z THIS AFTN TO 08Z EARLY SATURDAY MORNING.
AS FOR TEMPERATURES AND DEWPOINTS...IT WILL BE ANOTHER VERY WARM
TO LOCALLY HOT DAY WITH HIGHS GENERALLY IN THE UPPER 80S TO THE
LOWER 90S AND DEWPOINTS IN THE MID 60S TO AROUND 70. THIS SHOULD
KEEP HEAT INDICES IN THE MID TO UPPER 90S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING INTO THE
EVENING ACROSS THE REGION PARTICULARLY IN THE EAST BEFORE MOVING
OFF AS THE COLD FRONT CONTINUES TO PROGRESS EASTWARD. INCREASED
LOW LEVEL MOISTURE AND WEAK COLD ADVECTION BEHIND THE FRONT SHOULD
RESULT IN THE DEVELOPMENT OF LOW CLOUDS THAT WILL LAST WELL INTO
SATURDAY MORNING. COULD STILL SEE A FEW SHOWERS AND THUNDERSTORMS
DEVELOP ON SATURDAY PRIMARILY IN THE NORTHERN COUNTIES WITH
HEATING AND A WEAK DISTURBANCE DROPPING INTO THE UPPER TROUGH. AS
HIGH PRESSURE BUILDS OVER THE AREA SATURDAY NIGHT AND SUNDAY...
CONDITIONS WILL BE QUIESCENT.
FOLLOWING RECENT TRENDS HAVE PATTERNED TEMPERATURE FORECAST NEAR
OR SLIGHTLY ABOVE WARMER MOS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE WEEK. THIS PATTERN
IS CONDUCIVE TO CONVECTIVE DEVELOPMENT AS DISTURBANCES DROP
SOUTHEAST. HOWEVER THESE DISTURBANCES ARE OFTEN DIFFICULT TO TRACK
AND TIME. AT THIS POINT HAVE INCLUDED LOW CHANCE POPS MAINLY
DURING THE DAYTIME PERIODS. TEMPERATURES WILL REMAIN ABOVE NORMAL.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SOME MVFR FOG WILL BE POSSIBLE AT THE START OF THE TAF PERIOD
HOWEVER EXPECT VSBYS TO IMPROVE TO VFR BY 13Z. IN ADDITION SOME
IFR CIGS WILL LINGER AT KILN THROUGH 13Z. A COLD FRONT WILL
APPROACH THE TAF SITES TODAY ALLOWING FOR SCATTERED SHOWER AND
THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND INTO THE EARLY EVENING
HOURS. DUE TO UNORGANIZED NATURE OF CONVECTION HAVE LIMITED
THUNDERSTORM MENTION TO VCTS FOR A FEW HOURS LATER THIS AFTERNOON.
THUNDERSTORMS WILL TAPER OFF THIS EVENING. LOW CLOUDS WILL MOVE
INTO THE AREA TAF SITES AGAIN TONIGHT. IN ADDITION...SOME FOG WILL
DEVELOP AS WELL ACROSS THE TAF SITES TONIGHT.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ079>082-088.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ098>100.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...
LONG TERM...
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS MEDFORD OR
847 PM PDT SAT JUL 28 2012
.DISCUSSION...THE CURRENT FORECAST REMAINS ON TRACK THIS EVENING
AND THUS NO UPDATES ARE PLANNED. CUMULUS DEVELOPMENT OCCURRED OVER
PORTIONS OF THE SISKIYOUS AND CASCADES EARLIER THIS EVENING, BUT
THE VAST MAJORITY OF THE CONVECTION (INCLUDING ALL THAT WAS DEEP
ENOUGH TO PRODUCE ANY PRECIP AND/OR LIGHTNING) WAS EAST OF OUR
FORECAST AREA. ALL IS NEARLY GONE NOW AND THUS BEGINS ANOTHER
TRANQUIL NIGHT FOR SW OREGON AND NORCAL. STRATUS ALREADY COVERS
MUCH OF COOS COUNTY BUT HAS INITIALLY FORMED INLAND FROM THE
COASTLINE. WITH CONTINUED ONSHORE FLOW, NO REASON TO THINK IT
WON`T BACK BUILD TO THE COAST AND SPREAD INLAND AT LEAST AS FAR AS
LAST NIGHT. 29/00Z NAM AND RUC CONTINUE TO SHOW THE POTENTIAL FOR
STRATUS TO PUNCH ALL THE WAY INTO THE ROGUE VALLEY BY MORNING. BUT
AS NOTED BY AVIATION FORECASTER (BELOW) THIS IS A VERY LOW
PROBABILITY EVENT FOR MEDFORD PROPER IN AUGUST. WILL LEAVE PARTLY
CLOUDY SKIES WE HAVE JUST IN CASE, BUT IT WOULD NOT BE SURPRISING
TO REMAIN CLEAR ALL NIGHT. THE REST OF THE AREA (EAST SIDE AND
NORCAL) WILL REMAIN CLEAR TONIGHT. -WRIGHT
&&
.AVIATION..., STRATUS WITH MVFR/IFR CIGS HAS ALREADY FORMED OVER
THE WESTERN UMPQUA AND NORTH COAST INLAND FROM THE COASTLINE.
PRESSURE GRADIENTS ARE EVEN MORE ONSHORE THIS EVENING COMPARED TO
YESTERDAY AND THUS STRATUS WILL LIKELY BACK BUILD TO THE COAST AS
WELL AS SPREAD INLAND OVERNIGHT. CIGS WILL FLIRT WITH IFR ALONG
THE NORTH COAST BY SUNDAY MORNING AND THERE COULD ALSO BE A
LITTLE DRIZZLE. EXPECT MVFR CIGS TO PUSH INTO KRBG BY AROUND 11Z.
DOUGLAS/COOS COUNTY COASTAL RANGES WILL LIKELY BE OBSCURED. RIGHT
NOW, WE`RE NOT ANTICIPATING THE STRATUS TO BE DEEP ENOUGH TO SPILL
OVER THE UMPQUA DIVIDE INTO THE ROGUE VALLEY. THIS WOULD BE A VERY
LOW PROBABILITY EVENT FOR LATE-JULY AS CLIMATE STATS SHOW LESS
THAN A 2% PROBABILITY OF OCCURRENCE FOR AN MVFR CIG AT KMFR. EVEN
SO, COULD STILL SEE STRATUS PUSH THROUGH THE GAP INTO NORTHERN
JOSEPHINE COUNTY AND PERHAPS NEAR GRANTS PASS OR THE ILLINOIS
VALLEY BY SUNRISE SUNDAY. CIGS SHOULD CLEAR BACK TO THE COAST
AGAIN SUNDAY AFTERNOON. VFR EXPECTED TO CONTINUE ACROSS THE EAST
SIDE AND NORCAL THROUGH SUNDAY. -SPILDE/WRIGHT
&&
.PREV DISCUSSION... /ISSUED 300 PM PDT SAT JUL 28 2012/
DISCUSSION...
A DRY UPPER LEVEL SHORTWAVE TROUGH LIFTING NORTHEAST OUT OF NEVADA
AND INTO IDAHO COMBINING WITH A MARITIME UPPER LEVEL SHORTWAVE
TROUGH PUSHING EASTWARD FROM THE COAST TO GENERATE SOME CUMULUS OF
NOTE IN THE SOUTHEASTERN CORNER OF THE FORECAST AREA. IN THIS
LOCATION ISOLATED THUNDERSTORMS WILL BE POSSIBLE LATE THIS
AFTERNOON AND EVENING. OTHERWISE MID TO UPPER LEVEL MOISTURE WILL
BE INSUFFICIENT FOR THUNDERSTORMS.
TONIGHT MODELS INDICATE THE MARINE LAYER MAKING IT FURTHER INLAND
THAN LAST NIGHT, POSSIBLY ALL THE WAY TO THE CASCADES AND
SISKIYOUS ON SUNDAY MORNING. AT THIS POINT THINK THE MEDFORD AREA WILL
LIKELY SEE SCATTERED CLOUDS IN THE MORNING. IS THIS CLOUD COVER
DOES MAKE IT A COOLER MORNING WILL MEAN TEMPERATURES A BIT COOLER
TOMORROW VERSUS TODAY.
TONIGHT THROUGH TOMORROW A MOISTURE STARVED SHORTWAVE TROUGH
STRONGER THAN THOSE OF THE LAST COUPLE OF DAYS WILL MOVE WEST OF
THE AREA, SKIRTING US WITH HIGH CLOUDS AND HELPING TO NUDGE MARINE
AIR INLAND A BIT FURTHER.
MONDAY THROUGH NEXT WEEKEND MODELS INDICATE A GRADUAL WARMING
TREND WITH THE POSSIBILITY OF TEMPERATURES NEAR 100F IN MEDFORD
NEXT WEEKEND. CONFIDENCE IN THE 100F FORECAST FOR NEXT WEEKEND IS
ONLY MODERATE AT THIS TIME, AS THE GUIDANCE HAS BEEN STRUGGLING
WITH WHAT TO DO WITH A TROUGH NEAR THE PACNW DURING THIS PERIOD.
TRENDS ARE TO LINGER IT OFFSHORE LONGER ALLOWING 500MB HEIGHTS TO
REACH 588 TO 592. NEXT WEEKEND, SHOULD TODAY`S MODELS VERIFY, WE
WILL STAND SOME POTENTIAL FOR MONSOONAL MOISTURE RIPPLING OUR WAY
FROM ALONG AND NEAR THE SIERRA CREST. BTL
CLIMATE... TODAY IS THE 703RD CONSECUTIVE DAY WITHOUT AN OFFICIAL
HIGH TEMPERATURE OF 100F IN MEDFORD. MODEL GUIDANCE IS NOW SHOWING
A REAL POSSIBILITY OF 100+ SOMETIME NEXT WEEKEND. TODAY`S 850MB
TEMPS FROM THE GUIDANCE INDICATE A HIGH BETWEEN 98F AND 104F FOR
NEXT SATURDAY, AUGUST 4TH. FOR NOW, HAVE ENTERED 100F IN THE
FORECAST GIVEN THE MODELS` GENERAL TENDENCY OVERDO THE 850MB TEMPS
IN THE EXTENDED THIS SUMMER. MODEL ENSEMBLE MEANS INDICATE WE WILL
BE CLOSE TO 100F AS WELL. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 11 AM SUNDAY TO 5 PM PDT
THURSDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 AM SUNDAY TO 5
PM PDT THURSDAY FOR PZZ376.
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A STATIONARY FRONT LINGERING OVER OUR REGION WILL SLOWLY DISSIPATE
IN THE FIRST HALF OF THE WEEK. WEAK HIGH PRESSURE WILL RIDGE IN
FROM THE WEST AS AN UPPER TROUGH LINGERS OVER THE EAST COAST FOR THE
REST OF THE WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AT 1030 PM... 500 MB TROUGH AND ASSOCIATED COLDER TEMPERATURES
ALOFT MOVING ACROSS AREA AT THIS TIME HELPING TO PROMOTE PERSISTENT
CONVECTIVE STORM DEVELOPMENT NEAR CAPE GRADIENT THAT EXTENDS
NORTHEAST/SOUTHWEST JUST EAST OF THE CWA NEAR SURFACE TROUGH. HIGHER
CAPE AIR MASS CURVES AROUND SOUTHERN PERIPHERY OF CWA WHERE ISOLATED
STORMS ARE OCCURRING... INCLUDING SEVERAL LATE EVENING STORMS JUST
WEST OF HART AND ELBERT COUNTIES. REMAINDER AREA SEEMS TO BE IN
SLIGHTLY DRIER AND MORE STABLE AIR. EXPECT THE LINGERING SHOWERS AND
THUNDERSTORMS TO WIND DOWN DURING THE NEXT SEVERAL HOURS AS 500 MB
SHORT WAVE TROUGH MOVES EAST.
AT 745 PM... ONLY ISOLATED CONVECTIVE STORMS EXIST AT THIS TIME...
PRIMARILY IN THE SOUTHEASTERN CORNER OF THE CWA. SEVERAL SMALL
SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND JUST WEST OF RABUN
COUNTY ARE WEAKENING. WILL CONTINUE TO HIGHLIGHT THE EASTERN...
ESPECIALLY THE SOUTHEASTERN... ZONES WITH THE HIGHEST POPS BUT WILL
LOWER THEM THROUGH THE EVENING. THE LATEST RAP SBCAPE FORECAST
PERSIST IN HOLDING THE HIGHEST VALUES TO OUR EAST WITH SBCIN
BECOMING EVIDENT ACROSS MOST OF THE AREA AS THE BOUNDARY LAYER
SLOWLY COOLS AFTER SUNSET. MODELS CONTINUE TO INDICATE 500 MB
VORTICITY MAXIMUM CROSSING AREA TONIGHT... BUT WITH A CONSIDERABLE
AMOUNT OF DRY AIR IN THE MID-LEVELS AND A STABILIZING BOUNDARY
LAYER... IT APPEARS HIGHLY UNLIKELY THAT MUCH NEW CONVECTION WILL
OCCUR. PRIMARY CONTRIBUTOR TO CONVECTIVE STORM DEVELOPMENT THIS
EVENING WILL BE STEEPENING LAPSE RATES CAUSED BY COLD AIR ALOFT IN
SHORT WAVE TROUGH... BUT THAT WILL BE WORKING AGAINST INCREASING
SBCIN.
AT 430 PM... ISOLATED STRONG THUNDERSTORMS MOVING OUT OF THE
FOOTHILLS INTO THE PIEDMONT ARE DRAWING UPON SBCAPES OF ABOUT 1500
J/KG IN AN ENVIRONMENT OF DCAPES EXHIBITING VALUES BETWEEN 1300 AND
1500 J/KG. STORMS ARE MOVING TOWARD REGION OF HIGHER CAPES JUST TO
THE EAST OF OUR CWA... SO IT IS LIKELY THEY WILL CONTINUE OR
CONTRIBUTE TO ADDITIONAL OUTFLOW BOUNDARY-FORCED DEVELOPMENT.
EFFECTIVE BULK SHEAR IS SUFFICIENTLY STRONG TO CONTRIBUTE TO STORM
ORGANIZATION. HIGHEST POPS DURING REST OF THE AFTERNOON AND INTO THE
EVENING ARE IN THE TRANSITION ZONE TO HIGHER CAPES IN EASTERN
PORTION OF CWA. HAVE ADJUSTED POPS UP SOMEWHAT TO ACCOUNT FOR
ONGOING CONVECTIVE STORMS AT FORECAST ISSUANCE TIME.
AS OF 230 PM...DEWPOINTS HAVE MIXED OUT INTO THE LOW TO MID 60S
ACROSS THE NORTHERN UPSTATE AND THE NC FOOTHILLS DOWN TO CHARLOTTE.
DEWPOINTS CONTINUE TO POOL TO THE EAST/SOUTH OF THE LEE TROUGH
THROUGH THE SOUTHERN UPSTATE TO SOUTH OF CHARLOTTE WITH LOW TO MID
70S THERE. BASED ON THE DRYER AIR WORKING IN...EXPECT THAT
CONVECTION WILL REMAIN WIDELY SCATTERED ACROSS WESTERN AREAS THIS
AFTERNOON. THE BEST COVERAGE WILL OCCUR DURING THE LATE
AFTERNOON/EARLY EVENING HOURS ALONG THE MOISTURE GRADIENT AND WHERE
SBCAPES ARE THE HIGHEST IN EXCESS 2000J. LOOKS LIKE 55DBZ CORES TO
24K WILL BE ENOUGH FOR SEVERE TODAY BASED ON DCAPES >1000J. DAMAGING
MICROBURSTS WILL BE THE PRIMARY SEVERE THREAT.
THE AFTERNOON CONVECTION WILL BE DRIVEN BY A SHORT WAVE MOVING SE
THROUGH THE AREA ALONG WITH A WEAKENING SURFACE COLD FRONT WHICH
WILL SLIP INTO THE LEE TROUGH POSITION TONIGHT. AS THE UPPER WAVE
DEPARTS AND WITH THE LOSS OF HEATING...CONVECTION SHOULD WANE ACROSS
SOUTHERN AREAS BY 04Z. FOR THE OVERNIGHT...IT SHOULD BE CLEAR TO
PARTLY CLOUDY AND WARM AGAIN WITH LOWS REMAINING ABOVE AVERAGE.
AREAS OF MOUNTAIN VALLEY FOG ARE LIKELY LATE TONIGHT.
ON SUNDAY...WEAK SURFACE HIGH PRESSURE WILL RIDGE SOUTHWARD ACROSS
THE AREA AS THE WEAK FRONTAL/MOISTURE BOUNDARY MOVES SE OF THE AREA.
FORECAST SOUNDINGS INDICATE THAT A MID LEVEL INVERSION WILL SERVE TO
CAP ANY DEEP CONVECTION FROM DEVELOPING. THE ONLY EXCEPTION MAY BE
THE HIGHEST PEAKS. WITH STRONG INSOLATION ON SUNDAY...EXPECT ANOTHER
VERY WARM/TO HOT DAY. HIGHS WILL REACH THE LOW TO MID 90S OUTSIDE OF
THE MOUNTAINS WITH LOW TO MID 80S MOUNTAIN VALLEYS. HOWEVER...
DEWPOINTS ARE FORECAST TO MIX OUT INTO THE LOWER TO MID 60S...WITH
EVEN SOME 50S IN THE MOUNTAINS...SO HUMIDITY LEVELS WILL BE BELOW
MID SUMMER AVERAGE LEVELS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT SATURDAY...THE MEAN EAST COAST UPPER TROUGH WILL
PERSIST FROM SUNDAY NIGHT THROUGH TUESDAY. A SHORTWAVE WILL MOVE
INTO THE TROUGH ON SUNDAY NIGHT...ROUNDING ITS BASE ON MONDAY. THE
MODELS SHOW THE GREATEST MOISTURE OFF TO OUR EAST AND SOUTH ALONG
THE REMAINS OF A SURFACE FRONT...BUT MODEL TIME HEIGHTS SHOW A THIN
MOIST LAYER AT AROUND 800 MB. THE GFS AND NAM HAVE THEIR USUAL
DISPARITY IN REGARDS TO INSTABILITY...BUT EVEN A MEAN OF THE TWO
WOULD HAVE CAPE EXCEEDING 1000 J/KG...AND PLENTY OF DRY AIR EXISTS
FOR EVAPORATIVE COOLING. WITH WEAK SHEAR...PULSE TYPE SEVERE
THUNDERSTORMS WOULD NOT BE OUT OF THE QUESTION. WEAK STEERING FLOW
MAY ALLOW SOME THUNDERSTORMS TO PUT DOWN LOCALLY HEAVY RAINFALL...
BUT WITH MOISTURE RATHER LIMITED...NO WIDESPREAD HYDROLOGICAL
PROBLEMS ARE FORESEEN. TEMPERATURES WILL RUN AROUND NORMAL.
AN UPPER IMPULSE WILL MOVE INTO THE TROUGH ON TUESDAY. THE MODELS
SHOW MORE MOISTURE OVER THE AREA...AS THE REMAINS OF THE OLD
BOUNDARY LIFT NORTH ACROSS OUR AREA AS A WARM FRONT. THE MODEL
SOUNDINGS FOR TUESDAY ARE MORE MOIST AND HAVE SLIGHTLY BETTER WIND
SHEAR. SLIGHTLY BETTER STEERING FLOW SHULD KEEPI RAINFALL TOTALS
FROM BECOMING PROBLEMATIC...DESPITE DEEPER MOISTURE DEPICTED IN
MODEL TIME HEIGHTS. TEMPERATURES WILL REMAIN NEAR NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AT 200 PM EDT SATURDAY...AN EAST COAST UPPER TROUGH WILL PERSIST
FROM WEDNESDAY INTO FRIDAY...THEN WILL DEAMPLIFY ON SATURDAY. AT THE
SURFACE...WEAK HIGH PRESSURE WILL REMAIN OVER OUR AREA...WITH NORMAL
SUMMERTIME MOISTURE EXPECTED. WEAK UPPER IMPULSES MOVING THROUGH THE
TROUGH WILL BE DIFFICULT TO TIME...BUT WILL BE THE BEST FORCING FOR
ANYTHING OTHER THAN HEAT OR OROGRAPHICALLY INDUCED CONVECTION. POPS
WILL BE HELD AT NEAR CLIMATOLOGICAL NORMALS...WITH CHANCE POPS IN
THE MOUNTAINS...AND SLIGHT CHANCE IN THE LEE...MAXIMIZED WITH
AFTERNOON HEATING. THE LOWEST POPS WILL BE ON SATURDAY...WITH THE
EXPECTED INCREASE IN MID LEVEL TEMPERATURES AS THE UPPER TROUGH
WEAKENS. TEMPERATURES WILL BE NEAR OF SLIGHTLY BELOW NORMAL UNDER
THE UPPER TROUGH...WITH A SLIGHT INCREASE SATURDAY AS HEIGHTS RISE
ALOFT.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
AT KCLT... NO SIGNIFICANT WEATHER EXPECTED OVERNIGHT. AIR MASS
MOST FAVORABLE FOR SUPPORTING CONVECTIVE STORM DEVELOPMENT IS EAST
OF THE TERMINAL AREA. SCATTERED LOW AND MID-LEVEL DEBRIS CLOUDS NEAR
5K FT AND 15K FT FROM PREVIOUS STORMS ARE EXPECTED. WIND WILL BE
SOUTHWEST 5 KT BECOMING LIGHT AND VARIABLE OVERNIGHT. BETWEEN 09Z AND
13Z VISIBILITY NEAR 5 MI IN HAZE. AFTER 13Z... ONLY SCATTERED CLOUDS
NEAR 5 KT FT AND UNRESTRICTED VISIBILITY DURING REMAINDER OF THE
FORECAST PERIOD.
ELSEWHERE... NO SIGNIFICANT CLOUDS OR WEATHER THIS EVENING AS WEAK
HIGH PRESSURE SYSTEM BUILDS IN FROM THE NORTHWEST. LIGHT AND
VARIABLE WIND EXCEPT NORTH AROUND 10 KT AT KAVL. VISIBILITY LOWERING
TO NEAR 3 MI AT KAVL AFTER 03Z... BUT BECOMING UNRESTRICTED AFTER
13Z. DURING SUNDAY... SCATTERED CLOUDS NEAR 5 KT AND UNRESTRICTED
VISIBILITY.
OUTLOOK...SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED
EACH DAY THROUGH THE MIDDLE OF NEXT WEEK...WITH THE MOUNTAIN VALLEYS
HAVING THE BEST CHANCE OF MORNING FOG OR LOW CLOUDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...LGL
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
802 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL SLOWLY SETTLE SOUTHEAST ACROSS THE REGION
THROUGH THE WEEKEND BEFORE GRADUALLY DISSIPATING ON TUESDAY. HIGH
PRESSURE WILL THEN DOMINATE THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AT 745 PM... ONLY ISOLATED CONVECTIVE STORMS EXIST AT THIS TIME...
PRIMARILY IN THE SOUTHEASTERN CORNER OF THE CWA. SEVERAL SMALL
SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND JUST WEST OF RABUN
COUNTY ARE WEAKENING. WILL CONTINUE TO HIGHLIGHT THE EASTERN...
ESPECIALLY THE SOUTHEASTERN... ZONES WITH THE HIGHEST POPS BUT WILL
LOWER THEM THROUGH THE EVENING. THE LATEST RAP SBCAPE FORECAST
PERSIST IN HOLDING THE HIGHEST VALUES TO OUR EAST WITH SBCIN
BECOMING EVIDENT ACROSS MOST OF THE AREA AS THE BOUNDARY LAYER
SLOWLY COOLS AFTER SUNSET. MODELS CONTINUE TO INDICATE 500 MB
VORTICITY MAXIMUM CROSSING AREA TONIGHT... BUT WITH A CONSIDERABLE
AMOUNT OF DRY AIR IN THE MID-LEVELS AND A STABILIZING BOUNDARY
LAYER... IT APPEARS HIGHLY UNLIKELY THAT MUCH NEW CONVECTION WILL
OCCUR. PRIMARY CONTRIBUTOR TO CONVECTIVE STORM DEVELOPMENT THIS
EVENING WILL BE STEEPENING LAPSE RATES CAUSED BY COLD AIR ALOFT IN
SHORT WAVE TROUGH... BUT THAT WILL BE WORKING AGAINST INCREASING
SBCIN.
AT 430 PM... ISOLATED STRONG THUNDERSTORMS MOVING OUT OF THE
FOOTHILLS INTO THE PIEDMONT ARE DRAWING UPON SBCAPES OF ABOUT 1500
J/KG IN AN ENVIRONMENT OF DCAPES EXHIBITING VALUES BETWEEN 1300 AND
1500 J/KG. STORMS ARE MOVING TOWARD REGION OF HIGHER CAPES JUST TO
THE EAST OF OUR CWA... SO IT IS LIKELY THEY WILL CONTINUE OR
CONTRIBUTE TO ADDITIONAL OUTFLOW BOUNDARY-FORCED DEVELOPMENT.
EFFECTIVE BULK SHEAR IS SUFFICIENTLY STRONG TO CONTRIBUTE TO STORM
ORGANIZATION. HIGHEST POPS DURING REST OF THE AFTERNOON AND INTO THE
EVENING ARE IN THE TRANSITION ZONE TO HIGHER CAPES IN EASTERN
PORTION OF CWA. HAVE ADJUSTED POPS UP SOMEWHAT TO ACCOUNT FOR
ONGOING CONVECTIVE STORMS AT FORECAST ISSUANCE TIME.
AS OF 230 PM...DEWPOINTS HAVE MIXED OUT INTO THE LOW TO MID 60S
ACROSS THE NORTHERN UPSTATE AND THE NC FOOTHILLS DOWN TO CHARLOTTE.
DEWPOINTS CONTINUE TO POOL TO THE EAST/SOUTH OF THE LEE TROUGH
THROUGH THE SOUTHERN UPSTATE TO SOUTH OF CHARLOTTE WITH LOW TO MID
70S THERE. BASED ON THE DRYER AIR WORKING IN...EXPECT THAT
CONVECTION WILL REMAIN WIDELY SCATTERED ACROSS WESTERN AREAS THIS
AFTERNOON. THE BEST COVERAGE WILL OCCUR DURING THE LATE
AFTERNOON/EARLY EVENING HOURS ALONG THE MOISTURE GRADIENT AND WHERE
SBCAPES ARE THE HIGHEST IN EXCESS 2000J. LOOKS LIKE 55DBZ CORES TO
24K WILL BE ENOUGH FOR SEVERE TODAY BASED ON DCAPES >1000J. DAMAGING
MICROBURSTS WILL BE THE PRIMARY SEVERE THREAT.
THE AFTERNOON CONVECTION WILL BE DRIVEN BY A SHORT WAVE MOVING SE
THROUGH THE AREA ALONG WITH A WEAKENING SURFACE COLD FRONT WHICH
WILL SLIP INTO THE LEE TROUGH POSITION TONIGHT. AS THE UPPER WAVE
DEPARTS AND WITH THE LOSS OF HEATING...CONVECTION SHOULD WANE ACROSS
SOUTHERN AREAS BY 04Z. FOR THE OVERNIGHT...IT SHOULD BE CLEAR TO
PARTLY CLOUDY AND WARM AGAIN WITH LOWS REMAINING ABOVE AVERAGE.
AREAS OF MOUNTAIN VALLEY FOG ARE LIKELY LATE TONIGHT.
ON SUNDAY...WEAK SURFACE HIGH PRESSURE WILL RIDGE SOUTHWARD ACROSS
THE AREA AS THE WEAK FRONTAL/MOISTURE BOUNDARY MOVES SE OF THE AREA.
FORECAST SOUNDINGS INDICATE THAT A MID LEVEL INVERSION WILL SERVE TO
CAP ANY DEEP CONVECTION FROM DEVELOPING. THE ONLY EXCEPTION MAY BE
THE HIGHEST PEAKS. WITH STRONG INSOLATION ON SUNDAY...EXPECT ANOTHER
VERY WARM/TO HOT DAY. HIGHS WILL REACH THE LOW TO MID 90S OUTSIDE OF
THE MOUNTAINS WITH LOW TO MID 80S MOUNTAIN VALLEYS. HOWEVER...
DEWPOINTS ARE FORECAST TO MIX OUT INTO THE LOWER TO MID 60S...WITH
EVEN SOME 50S IN THE MOUNTAINS...SO HUMIDITY LEVELS WILL BE BELOW
MID SUMMER AVERAGE LEVELS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT SATURDAY...THE MEAN EAST COAST UPPER TROUGH WILL
PERSIST FROM SUNDAY NIGHT THROUGH TUESDAY. A SHORTWAVE WILL MOVE
INTO THE TROUGH ON SUNDAY NIGHT...ROUNDING ITS BASE ON MONDAY. THE
MODELS SHOW THE GREATEST MOISTURE OFF TO OUR EAST AND SOUTH ALONG
THE REMAINS OF A SURFACE FRONT...BUT MODEL TIME HEIGHTS SHOW A THIN
MOIST LAYER AT AROUND 800 MB. THE GFS AND NAM HAVE THEIR USUAL
DISPARITY IN REGARDS TO INSTABILITY...BUT EVEN A MEAN OF THE TWO
WOULD HAVE CAPE EXCEEDING 1000 J/KG...AND PLENTY OF DRY AIR EXISTS
FOR EVAPORATIVE COOLING. WITH WEAK SHEAR...PULSE TYPE SEVERE
THUNDERSTORMS WOULD NOT BE OUT OF THE QUESTION. WEAK STEERING FLOW
MAY ALLOW SOME THUNDERSTORMS TO PUT DOWN LOCALLY HEAVY RAINFALL...
BUT WITH MOISTURE RATHER LIMITED...NO WIDESPREAD HYDROLOGICAL
PROBLEMS ARE FORESEEN. TEMPERATURES WILL RUN AROUND NORMAL.
AN UPPER IMPULSE WILL MOVE INTO THE TROUGH ON TUESDAY. THE MODELS
SHOW MORE MOISTURE OVER THE AREA...AS THE REMAINS OF THE OLD
BOUNDARY LIFT NORTH ACROSS OUR AREA AS A WARM FRONT. THE MODEL
SOUNDINGS FOR TUESDAY ARE MORE MOIST AND HAVE SLIGHTLY BETTER WIND
SHEAR. SLIGHTLY BETTER STEERING FLOW SHULD KEEPI RAINFALL TOTALS
FROM BECOMING PROBLEMATIC...DESPITE DEEPER MOISTURE DEPICTED IN
MODEL TIME HEIGHTS. TEMPERATURES WILL REMAIN NEAR NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AT 200 PM EDT SATURDAY...AN EAST COAST UPPER TROUGH WILL PERSIST
FROM WEDNESDAY INTO FRIDAY...THEN WILL DEAMPLIFY ON SATURDAY. AT THE
SURFACE...WEAK HIGH PRESSURE WILL REMAIN OVER OUR AREA...WITH NORMAL
SUMMERTIME MOISTURE EXPECTED. WEAK UPPER IMPULSES MOVING THROUGH THE
TROUGH WILL BE DIFFICULT TO TIME...BUT WILL BE THE BEST FORCING FOR
ANYTHING OTHER THAN HEAT OR OROGRAPHICALLY INDUCED CONVECTION. POPS
WILL BE HELD AT NEAR CLIMATOLOGICAL NORMALS...WITH CHANCE POPS IN
THE MOUNTAINS...AND SLIGHT CHANCE IN THE LEE...MAXIMIZED WITH
AFTERNOON HEATING. THE LOWEST POPS WILL BE ON SATURDAY...WITH THE
EXPECTED INCREASE IN MID LEVEL TEMPERATURES AS THE UPPER TROUGH
WEAKENS. TEMPERATURES WILL BE NEAR OF SLIGHTLY BELOW NORMAL UNDER
THE UPPER TROUGH...WITH A SLIGHT INCREASE SATURDAY AS HEIGHTS RISE
ALOFT.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT... NO SIGNIFICANT WEATHER EXPECTED THIS EVENING. AIR MASS
MOST FAVORABLE FOR SUPPORTING CONVECTIVE STORM DEVELOPMENT IS EAST
OF THE TERMINAL AREA. SCATTERED LOW AND MID-LEVEL DEBRIS CLOUDS NEAR
5K FT AND 15K FT FROM PREVIOUS STORMS ARE EXPECTED. WIND WILL BE
SOUTHWEST 5 KT BECOMING LIGHT AND VARIABLE OVERNIGHT. BETWEEN 09Z AND
13Z VISIBILITY NEAR 5 MI IN HAZE. AFTER 13Z... ONLY SCATTERED CLOUDS
NEAR 5 KT FT AND UNRESTRICTED VISIBILITY DURING REMAINDER OF THE
FORECAST PERIOD.
ELSEWHERE... NO SIGNIFICANT CLOUDS OR WEATHER THIS EVENING AS WEAK
HIGH PRESSURE SYSTEM BUILDS IN FROM THE NORTHWEST. LIGHT AND
VARIABLE WIND EXCEPT NORTH AROUND 10 KT AT KAVL. VISIBILITY LOWERING
TO NEAR 3 MI AT KAVL AFTER 03Z... BUT BECOMING UNRESTRICTED AFTER
13Z. DURING SUNDAY... SCATTERED CLOUDS NEAR 5 KT AND UNRESTRICTED
VISIBILITY.
OUTLOOK...SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED
EACH DAY THROUGH THE MIDDLE OF NEXT WEEK...WITH THE MOUNTAIN VALLEYS
HAVING THE BEST CHANCE OF MORNING FOG OR LOW CLOUDS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...LGL
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
151 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A WEAK COOL FRONT WILL SLOWLY SETTLE SOUTHEAST ACROSS THE REGION
THROUGH THE WEEKEND BEFORE GRADUALLY DISSIPATING. ANOTHER WEAK FRONT
IS EXPECTED TO APPROACH THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM...CONVECTION BEGINNING TO FIRE AS ANTICIPATED. LOOKS
LIKE CURRENT POP GRIDS IN GOOD SHAPE AS WELL AS TEMP TRENDS. SO NO
SIGNIFICANT ADJUSTMENTS NECESARY EXCEPT FOR SOME MINOR TWEAKS.
PREVIOUS DISCUSSION:
AS OF 1030 AM...MOST COMPLICATED PART OF THE FORECAST AS USUAL DURING THE
SUMMER IS THE CONVECTIVE COMPONENT. THERE WILL CERTAINLY BE SOME
DEEP CONVECTION THIS AFTERNOON...BUT THERE ARE COVERAGE AND
INTENSITY QUESTIONS. THE MESO MODELS LIKE THE HRRR AND RAP GEN UP
CONVECTION EARLY THIS AFTERNOON IN THE LEE OF THE MOUNTAINS IN
WESTERN NC APPARENTLY RESPONDING TO WEAK VORT MX MOVING MOVING
THROUGH UPSTATE SC. SOME MID LEVEL CLOUDS ARE SHOWING UP THERE SO
THIS BASIC IDEA LOOKS REASONABLE. THE HRRR MOVES THIS INITIAL
CLUSTER SE WITH LITTLE DEVELOPMENT IN ITS WAKE. THE 12Z NAM HAS A
SIMILAR IDEA THOUGH MORE COVERAGE. I AM INCLINED TO BELIEVE THERE
WILL BE MORE COVERAGE THAN WHAT THE HRRR IMPLIES...ACTUALLY MORE
ALONG THE LINES OF THE NAM AND OUR LOCAL WRF. HENCE...HAVE TRENDED
THE POP FIELD IN THE MORE GENEROUS DIRECTION FOR TODAY. TEMP TRENDS LOOK
BANG ON FOR THE MOST PART SO ONLY MINOR CHANGES. CURRENT HEAT
ADVISORY ACROSS THE SOUTHERN PIEDMONT LOOKS WELL PLACED AND WILL
CONTINUE THAT.
IN REGARD TO THE SEVERE THREAT FOR TODAY...THE MID LEVEL FLOW WILL
BE MUCH BETTER TO THE N OF OUR AREA THIS AFTN...BUT 500 MB WINDS
COULD APPROACH 25 KT ACROSS THE FAR NRN TIER WHICH WOULD SUPPORT A
MULTICELL MODE THERE. FARTHER TO THE SOUTH...THE STRONGLY HEATED
BOUNDARY LAYER WILL PRODUCE CAPES INCREASING TO 1500-2000J WHICH
WILL SUPPORT A PULSE SEVERE THREAT PRIMARLY FOR WET MICROBURSTS.
SPC HAS PLACED THE AREA IN A SLIGHT RISK AREA.
EXPECT THAT CONVECTION SHOULD WANE QUICKLY THIS EVENING THANKS TO
WEAK NVA BEHIND DEPARTING VORT MAX. QUICK PEAK AT 12Z NAM SUPPORTS
THIS SCENARIO. WILL MAKE SOME ADJUSTMENTS TO TONIGHT`S POP GRIDS
MASED ON 12Z NAM. ANOTHER WARM AND MUGGY NIGHT IS IN STORE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...THE MODELS APPEAR TO AGREE IN SHUNTING THE
DEEPER MOISTURE TOWARD THE COASTAL PLAIN BY SATURDAY AFTERNOON.
HOWEVER...THERE IS SLIGHT DISAGREEMENT ON THE POSITION OF THE
SURFACE BOUNDARY...AND A MAJOR DISCREPANCY BETWEEN THE GFS AND THE
NAM ON THE DISTRIBUTION OF INSTABILITY ACROSS THE REGION SAT
AFTERNOON. THE GFS HAS A VERY SHARP CAPE GRADIENT...WITH VERY LITTLE
IN THE WAY OF INSTABILITY WEST OF THE FRONTAL ZONE (I.E. VERY LITTLE
INSTABILITY IN OUR AREA). MEANWHILE...THE NAM DEPICTS A MORE DIFFUSE
SURFACE BOUNDARY...WITH PLENTY OF LOW-LEVEL MOISTURE LINGERING TO
SUPPORT HIGH CAPE VALUES ACROSS THE CWA. CONSIDERING THE TIME OF
YEAR...AND EXAMINING CURRENT OBS WEST OF THE FRONTAL BOUNDARY...I
HAVE A DIFFICULT TIME BUYING IN TO THE GFS INSTABILITY PICTURE. THIS
HAS MAJOR FORECAST IMPLICATIONS...AS BOTH MODELS FEATURE A RATHER
POTENT SHORT WAVE TROUGH TRAVERSING THE AREA DURING THE AFTERNOON.
WITH THE LONG WAVE TROUGH AXIS OVERHEAD...THERE SHOULD BE A DECENT
AMOUNT OF DEEP LAYER SHEAR (25-30 KT)...AND THE SHORT WAVE COULD
PROMOTE DEVELOPMENT OF ORGANIZED CONVECTION DURING PEAK HEATING. IN
FACT...THE NAM IS DOING JUST THAT. IN LIGHT OF THE VERY DRY
MID-LEVELS ALONG WITH MODERATE DEEP LAYER SHEAR...CONVECTION MAY
TEND A LITTLE TOWARD DISCRETE CELLS...SO IM NOT PREPARED TO MAKE
MAJOR INCREASES IN POPS...BUT THEY HAVE BEEN INCREASED TO 30-40
PERCENT FROM THE BLUE RIDGE EAST. FORECAST SOUNDINGS DEPICT VERY
HIGH VALUES OF DCAPE...SO DAMAGING MICROBURSTS WOULD BE OF PRIMARY
CONCERN.
ANY CONVECTION WILL SWEEP EAST WITH THE SHORT WAVE SAT EVENING...
LEAVING MOSTLY DRY CONDITIONS THROUGH AT LEAST SUNDAY MORNING. THE
TROUGH AXIS REMAINS OVERHEAD SUNDAY...BUT RISING HEIGHTS IN THE WAKE
OF THE SHORT WAVE WILL RESULT IN GRADUALLY WEAKENING FLOW. IT
APPEARS THE BEST INSTABILITY WILL BE EAST OF THE AREA...BUT THERE
WILL BE MORE THAN ADEQUATE CAPE VALUES BENEATH DIFFLUENT FLOW ALOFT
TO SUPPORT ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON.
THE MODELS SUGGEST CONVECTION WILL LINGER INTO SUNDAY NIGHT...AS
MOISTURE DEEPENS IN RESPONSE TO THE APPROACH OF ANOTHER SHORT WAVE
TROUGH...SO AT LEAST SLIGHT CHANCES WILL EXIST ACROSS MUCH OF THE
AREA THROUGH THE OVERNIGHT. TEMPS WILL COOL SLIGHTLY BENEATH THE
UPPER TROUGH AXIS...BUT WILL STILL REMAIN AROUND NORMAL THROUGH THE
PERIOD.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 1215 PM FRIDAY...MEDIUM RANGE MODELS ARE CONTINUING TO
ADVERTISE THE POTENTIAL FOR ENERGY ROTATING INTO THE REGION ON
TUESDAY WITHIN THE BASE OF LINGERING EASTERN CONUS L/WV TROUGH.
GIVEN THE UNSETTLED LOOK OF THE LARGE SCALE PATTERN...SOLID CHANCE
POP WILL BE NUDGED UPWARD. INTO WEDNESDAY...THERE LOOKS TO BE LITTLE
CHANGE IN THE MEAN PATTERN AND ASSOCIATED SENSIBLE WX...DIURNALLY
ENHANCED TSTM CHANCES. DAILY TEMPERATURES WILL CONTINUE TO BE WITHIN
A FEW DEGREES OF CLIMO. I WOULD EXPECT ABOVE CLIMO TSTM CHANCES TO
CONTINUE INTO THURSDAY AS WELL GIVEN THE ONLY NOMINAL CHANGE TO THE
PATTERN ACRS THE EASTERN CONUS. THE LATEST ECMWF IS HINTING AT A
TRANSITION TOWARD A WEAKER/DEAMPLIFYING FLOW REGIME BY THE END OF
PERIOD. NEW DAY 7 POPS WILL FEATURE SLIGHT AND/OR SMALL DIURNAL
TSTM CHANCES AND TEMPERATURES NEAR PERSISTENCE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...TIMING OF CONVECTION AT THE AIRPORT IS MAIN PROBLEM.
LATEST LOCAL WRF RUN SEEMS TO BE CAPTURING CONVECTIVE TRENDS AND IT
SUGGESTS THUNDERSTORMS AROUND 20Z FOR THE AIRFIELD. HENCE...WILL
RUN A TEMPO FOR TSRA FROM 20-22Z AND THEN A VCSH TIL AROUND 00Z.
EXPECT AFTER 00Z ONLY SOME CONVECTIVE DEBRIS CLOUDS. IF
SUBSTANTIAL RAIN OCCURS AT THE AIRFIELD...CANT RULE OUT SOME MVFR
TYPE FOG EARLY ON SAT...BUT FOR NOW HAVE NOT INTRODUCED THAT. ON
SAT...THE MORNING SHOULD BE QUIET WITH CONVECTION ARRIVING AFTER
THIS TAF TIMEFRAME.
ELSEWHERE...SCATTERED TO NUMEROUS THUNDERSTORMS THIS AFTERNOON
ACROSS THE AREA TRIGGERED BY AN UPPER AIR DISTURBANCE.
HENCE...EXPECT ALL AIRFIELDS TO BE AFFECTED IN APPROXIMATELY 19Z-23Z
TIMEFRAME. EXPECT CONVECTION TO WANE QUICKLY AFTER 00Z AS TROUGH
MOVES TO THE EAST. EXPECT SOME IFR/LIFR MOUNTAIN VALLEY FOG AND
AROUND KHKY AS EXPECT MOST AREAS TO HAVE SOME RAINFALL.
CONVECTION ON SAT SHOULD BE AFTER THJIS TAF PERIOD.
OUTLOOK...A DAILY CHANCE OF SCT AFTERNOON CONVECTION WILL THEN
CONTINUE INTO THE MIDDLE OF NEXT WEEK AS AN UPPER TROF REMAINS OVER
THE AREA.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR GAZ029.
NC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ071-072-082.
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ009-011>014-
019.
&&
$$
SYNOPSIS...JDL
NEAR TERM...LG
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1044 AM EDT FRI JUL 27 2012
.SYNOPSIS...
MOISTURE WILL BE ON THE INCREASE TODAY AHEAD OF AN APPROACHING WEAK
COOL FRONT. THIS FRONT WILL SETTLE OVER THE REGION DURING THE
WEEKEND AND GRADUALLY DISSIPATE. ANOTHER WEAK FRONT IS EXPECTED TO
APPROACH THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM...MOST COMPLICATED PART OF THE FORECAST AS USUAL DURING THE
SUMMER IS THE CONVECTIVE COMPONENT. THERE WILL CERTAINLY BE SOME
DEEP CONVECTION THIS AFTERNOON...BUT THERE ARE COVERAGE AND
INTENSITY QUESTIONS. THE MESO MODELS LIKE THE HRRR AND RAP GEN UP
CONVECTION EARLY THIS AFTERNOON IN THE LEE OF THE MOUNTAINS IN
WESTERN NC APPARENTLY RESPONDING TO WEAK VORT MX MOVING MOVING
THROUGH UPSTATE SC. SOME MID LEVEL CLOUDS ARE SHOWING UP THERE SO
THIS BASIC IDEA LOOKS REASONABLE. THE HRRR MOVES THIS INITIAL
CLUSTER SE WITH LITTLE DEVELOPMENT IN ITS WAKE. THE 12Z NAM HAS A
SIMILAR IDEA THOUGH MORE COVERAGE. I AM INCLINED TO BELIEVE THEIR
WILL BE MORE COVERAGE THAN WHAT THE HRRR IMPLIES...ACTUALLY MORE
ALONG THE LINES OF THE NAM AND OUR LOCAL WRF. HENCE...HAVE
TRENDED THE POP FIELD IN THE MORE GENEROUS DIRECTION FOR TODAY.
TEMP TRENDS LOOK BANG ON FOR THE MOST PART SO ONLY MINOR CHANGES.
CURRENT HEAT ADVISORY ACROSS THE SOUTHERN PIEDMONT LOOKS WELL
PLACED AND WILL CONTINUE THAT.
IN REGARD TO THE SEVERE THREAT FOR TODAY...THE MID LEVEL FLOW WILL
BE MUCH BETTER TO THE N OF OUR AREA THIS AFTN...BUT 500 MB WINDS
COULD APPROACH 25 KT ACROSS THE FAR NRN TIER WHICH WOULD SUPPORT A
MULTICELL MODE THERE. FARTHER TO THE SOUTH...THE STRONGLY HEATED
BOUNDARY LAYER WILL PRODUCE CAPES INCREASING TO 1500-2000J WHICH
WILL SUPPORT A PULSE SEVERE THREAT PRIMARLY FOR WET MICROBURSTS.
SPC HAS PLACED THE AREA IN A SLIGHT RISK AREA.
EXPECT THAT CONVECTION SHOULD WANE QUICKLY THIS EVENING THANKS TO
WEAK NVA BEHIND DEPARTING VORT MAX. QUICK PEAK AT 12Z NAM SUPPORTS
THIS SCENARIO. WILL MAKE SOME ADJUSTMENTS TO TONIGHT`S POP GRIDS
MASED ON 12Z NAM. ANOTHER WARM AND MUGGY NIGHT IS IN STORE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...THE MODELS APPEAR TO AGREE IN SHUNTING THE
DEEPER MOISTURE TOWARD THE COASTAL PLAIN BY SATURDAY AFTERNOON.
HOWEVER...THERE IS SLIGHT DISAGREEMENT ON THE POSITION OF THE
SURFACE BOUNDARY...AND A MAJOR DISCREPANCY BETWEEN THE GFS AND THE
NAM ON THE DISTRIBUTION OF INSTABILITY ACROSS THE REGION SAT
AFTERNOON. THE GFS HAS A VERY SHARP CAPE GRADIENT...WITH VERY LITTLE
IN THE WAY OF INSTABILITY WEST OF THE FRONTAL ZONE (I.E. VERY LITTLE
INSTABILITY IN OUR AREA). MEANWHILE...THE NAM DEPICTS A MORE DIFFUSE
SURFACE BOUNDARY...WITH PLENTY OF LOW-LEVEL MOISTURE LINGERING TO
SUPPORT HIGH CAPE VALUES ACROSS THE CWA. CONSIDERING THE TIME OF
YEAR...AND EXAMINING CURRENT OBS WEST OF THE FRONTAL BOUNDARY...I
HAVE A DIFFICULT TIME BUYING IN TO THE GFS INSTABILITY PICTURE. THIS
HAS MAJOR FORECAST IMPLICATIONS...AS BOTH MODELS FEATURE A RATHER
POTENT SHORT WAVE TROUGH TRAVERSING THE AREA DURING THE AFTERNOON.
WITH THE LONG WAVE TROUGH AXIS OVERHEAD...THERE SHOULD BE A DECENT
AMOUNT OF DEEP LAYER SHEAR (25-30 KT)...AND THE SHORT WAVE COULD
PROMOTE DEVELOPMENT OF ORGANIZED CONVECTION DURING PEAK HEATING. IN
FACT...THE NAM IS DOING JUST THAT. IN LIGHT OF THE VERY DRY
MID-LEVELS ALONG WITH MODERATE DEEP LAYER SHEAR...CONVECTION MAY
TEND A LITTLE TOWARD DISCRETE CELLS...SO IM NOT PREPARED TO MAKE
MAJOR INCREASES IN POPS...BUT THEY HAVE BEEN INCREASED TO 30-40
PERCENT FROM THE BLUE RIDGE EAST. FORECAST SOUNDINGS DEPICT VERY
HIGH VALUES OF DCAPE...SO DAMAGING MICROBURSTS WOULD BE OF PRIMARY
CONCERN.
ANY CONVECTION WILL SWEEP EAST WITH THE SHORT WAVE SAT EVENING...
LEAVING MOSTLY DRY CONDITIONS THROUGH AT LEAST SUNDAY MORNING. THE
TROUGH AXIS REMAINS OVERHEAD SUNDAY...BUT RISING HEIGHTS IN THE WAKE
OF THE SHORT WAVE WILL RESULT IN GRADUALLY WEAKENING FLOW. IT
APPEARS THE BEST INSTABILITY WILL BE EAST OF THE AREA...BUT THERE
WILL BE MORE THAN ADEQUATE CAPE VALUES BENEATH DIFFLUENT FLOW ALOFT
TO SUPPORT ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON.
THE MODELS SUGGEST CONVECTION WILL LINGER INTO SUNDAY NIGHT...AS
MOISTURE DEEPENS IN RESPONSE TO THE APPROACH OF ANOTHER SHORT WAVE
TROUGH...SO AT LEAST SLIGHT CHANCES WILL EXIST ACROSS MUCH OF THE
AREA THROUGH THE OVERNIGHT. TEMPS WILL COOL SLIGHTLY BENEATH THE
UPPER TROUGH AXIS...BUT WILL STILL REMAIN AROUND NORMAL THROUGH THE
PERIOD.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 320 AM FRIDAY...THE MEDIUM RANGE WILL FEATURE VERY LITTLE
CHANGE IN THE SYNOPTIC PATTERN...AS GLOBAL MODELS AGREE THAT AN
EASTERN TROUGH WILL PERSIST THROUGH THE PERIOD. THEREFORE...AT LEAST
SCATTERED/MAINLY DIURNAL CONVECTION...OCCASIONALLY ENHANCED BY THE
PASSAGE OF WEAK SHORT WAVE TROUGHS...CAN BE EXPECTED THROUGH THE
PERIOD. IT ALSO APPEARS THAT A MORE SIGNIFICANT SHORT WAVE WILL PASS
OVER THE EASTERN CONUS TOWARD THE MIDDLE OF THE WEEK...BRINGING
ANOTHER COLD FRONT INTO THE AREA...ALTHOUGH THE TIMING OF THIS IS
UNCERTAIN. IN LIGHT OF THIS PATTERN...ABOVE CLIMO POPS AND NEAR
NORMAL TEMPS ARE WARRANTED THROUGH THE PERIOD.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...FEW TO SCT CIRRUS FROM NEARBY CONVECTION WILL PERSIST IN
THE TERMINAL AREA THIS MORNING. DEWPOINT POOLING ACROSS THE REGION
TODAY WILL THEN PERMIT CUMULUS DEVELOPMENT BY 17Z...WITH THE BEST
CHANCE OF TSRA TOWARD 21Z WITH THE PASSAGE OF A WEAK UPPER
SHORTWAVE. WINDS WILL BE SW LESS THAN 10 KT THROUGH THE
PERIOD...ALTHOUGH SOME BRIEF LOW END GUSTS TO THE LOWER TO MIDDLE
TEENS WILL BE POSSIBLE DURING PEAK MIXING. ACTIVITY WILL DISSIPATE
THIS EVENING WITH LINGERING DEBRIS CLOUDS INTO THE NIGHT.
ELSEWHERE...DEBRIS CLOUDINESS WILL PERSIST ACROSS THE REGION THIS
MORNING. THIS HAS KEPT THE FOG AT BAY...BUT BRIEF MVFR VSBY COULD
STILL OCCUR AT KAND...KAVL...AND KHKY. CUMULUS WILL DEVELOP BY 16Z
TO 18Z WITH HEATING AND DEWPOINT POOLING AHEAD OF AN APPROACHING
BOUNDARY. SCATTERED CONVECTION WILL THEN LIKELY DEVELOP BY 20Z TO
21Z WITH THE ARRIVAL OF A WEAK UPPER SHORTWAVE. EXPECT MAINLY SW
FLOW AT THE FOOTHILL SITES...WITH BRIEF LOW END GUSTS INTO THE LOWER
TO MIDDLE TEENS POSSIBLE AT TIMES...EXCEPT NW WINDS AT KAVL. DEBRIS
CLOUDS SHOULD LINGER INTO TONIGHT...WITH ANOTHER SHOT AT MVFR VSBY
TOWARD DAYBREAK...POSSIBLY IFR AT KAVL.
OUTLOOK...ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED ON SATURDAY AS
AN UPPER WAVE AND SFC COLD FRONT MOVE THROUGH THE REGION. A DAILY
CHANCE OF SCT AFTERNOON CONVECTION WILL THEN CONTINUE INTO THE
MIDDLE OF NEXT WEEK AS AN UPPER TROF REMAINS OVER THE AREA.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR GAZ029.
NC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ071-072-082.
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ009-011>014-
019.
&&
$$
SYNOPSIS...JDL
NEAR TERM...LG
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...HG
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1153 PM CDT THU JUL 26 2012
.UPDATE...
LOWERED POPS TO CHANCE OVERNIGHT. MAIN AREA OF PCPN HEADING INTO
THE NORTHERN PLATEAU ATTM. ANOTHER WARM DAY ON FRI WITH MORE
MOISTURE FOR AFTN STORMS SOUTH AND PLATEAU.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT THU JUL 26 2012/
UPDATE...
00Z TAF DISCUSSION.
AVIATION...
QLCS HAS DEVELOPED FROM N AR TO SW IN AND MOVING SOUTHEASTWARD
TOWARDS MID TN...WITH ISOLATED TSRA DEVELOPING IN FRONT OF THE
LINE AS WELL. LATEST LAPS ANALYSIS SHOWS A STRONG INSTABILITY
AXIS FROM SW TO NE ACROSS THE MID STATE WITH CAPES OF 2500-3000
J/KG...AND HRRR GUIDANCE INDICATES LINE WILL SURVIVE AND AFFECT
CKV AROUND 02Z BUT WEAKEN AS IT APPROACHES BNA AND CSV LATER
TONIGHT. WILL SHOW MAIN TSRA IMPACTS AT CKV THIS EVENING WITH
GUSTS TO 30 KTS AND IFR VIS POSSIBLE...AND STRATIFORM TSRA/SHRA
BEHIND THE MAIN LINE THROUGH THE EARLY MORNING HOURS. LESSER
IMPACTS EXPECTED WITH WEAKENING LINE AT BNA AND CSV WITH VCTS OR
TEMPO TSRA. BREAK IN ACTIVITY EXPECTED FRIDAY MORNING BEFORE
REDEVELOPMENT BY AFTERNOON ACROSS MIDDLE TENNESSEE WITH COLD FRONT
MOVING ACROSS.
PREV DISCUSSION... /ISSUED 623 PM CDT THU JUL 26 2012/
UPDATE...
SEVERE STORMS ASSOC WITH UNSTAB ATM AND H5 TROF DIGGING SOUTH OVR
THE OHVLY. LATEST MODELS DROP ANOTHER S/W TROF IN THE SOUTHERN
PLAINS MOVG SOUTHEAST. THIS SHOULD KEEP STORM ACTIVITY STRONG TO
SEVERE THIS EVENING...AS SYSTEM SPREADS INTO NORTHWEST CORNER OF
MID-TN BTW 8 AND 9 PM.
PREV DISCUSSION... /ISSUED 351 PM CDT THU JUL 26 2012/
DISCUSSION...
CAP ACROSS THE MID STATE IN A HOLDING PATTERN FOR NOW. COULD STILL
SEE SOME ISOL DEVELOPMENT THROUGH THIS EVENING. OTW...A FRONTAL
BOUNDARY IS LOCATED TO OUR NORTH ACROSS CENTRAL IL WITH BETTER
CONVECTION COVERAGE ALONG AND JUST SOUTH OF THIS FEATURE.
FOR TONIGHT...SHOULD SEE A 1-2 PUNCH IN TERMS OF CONVECTION CHANCES.
ISOLATED ACTIVITY IS EXPECTED THROUGH THIS EVENING. THEN...AS THE
AFOREMENTIONED FRONTAL BOUNDARY SINKS SOUTHWARD...A BETTER CHANCE
OF SHOWERS AND TSTMS WILL COMMENCE SOMETIME AROUND MIDNIGHT.
OVERNIGHT CAPE VALUES ARE QUITE IMPRESSIVE AND SINCE GRAPHICAL DEW
POINTS LOOK REASONABLE...STRONG TO PERHAPS SEVERE STORMS WILL BE
POSSIBLE. LATEST 3 HR PRESSURE CHANGE IN SUPPORT OF THE SOUTHWARD
MOVING BOUNDARY.
PRECIP PROBABILITIES WILL NOT BE ALL THAT HIGH TONIGHT AND TUESDAY.
MODELS ARE CONSISTENT WITH A RATHER NARROW RELATIVE DEEP MOISTURE
PROFILE. POPS WILL BE HELD DOWN INTO THE 30-50 PERCENT RANGE TONIGHT
AND FRIDAY.
CAPE VALUES WILL REMAIN ELEVATED THROUGH THE DAY ON FRIDAY. SO
AGAIN...STRONG TO SEVERE STORMS WILL BE POSSIBLE.
DRIER AIR WILL FINALLY WORK INTO THE AREA FRIDAY NIGHT. THIS DRY
PATTERN WILL EXTEND INTO THE FIRST PORTION OF THE EXTENDED FCST.
FOR THE SHORT TERM TEMPS...ABOVE NORMAL TEMPS TO CONTINUE BUT WE
WILL SEE MORE OF A DIURNAL RANGE THIS WEEKEND.
ADDITIONALLY...DEWPOINTS WILL LOWER INTO THE 60S FOR SATURDAY AND
SUNDAY...SO NICE WEEKEND COMING UP.
FOR THE EXT FCST...UPPER HIGH TO HOLD OVER TX AND THIS WILL KEEP
MIDDLE TN UNDER A NW FLOW REGIME. AFTER A DRY PERIOD THIS
WEEKEND...DISTURBANCES AND AN INCREASE IN MOISTURE WILL TRANSLATE
THE PATTERN INTO MORE OF AN ACTIVE NW FLOW. WILL THEREFORE INCLUDE A
CHANCE OF SHOWERS AND TSTMS BEGINNING ON TUESDAY. OTW...TEMPS TO
REMAIN ABOVE NORMAL. STILL A REASONABLE CHANCE THAT THIS JULY WILL
END UP BEING THE 2ND WARMEST ON RECORD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1151 PM CDT THU JUL 26 2012
.UPDATE...
06Z TAF DISCUSSION.
&&
.AVIATION...
GUST FRONT CURRENTLY STRETCHES SW TO NE ACROSS THE MIDDLE OF THE
CWA WITH SCATTERED SHRA/TSRA BEHIND THE BOUNDARY. INTERMITTENT
-SHRA WILL AFFECT CKV/BNA FOR A COUPLE MORE HOURS BEFORE ACTIVITY
DIES OFF...WHILE VCTS IS ANTICIPATED AT CSV WITH GUST FRONT
PASSAGE OVERNIGHT. ALL CONVECTION TO DISSIPATE BY SUNRISE WITH
SOME MVFR FOG POSSIBLE AT CKV DUE TO THE HEAVY RAINFALL EARLIER.
ADDITIONAL SHRA/TSRA EXPECTED BY FRIDAY AFTERNOON AS COLD
FRONT/DRIER AIR ALOFT FILTERS SOUTHWARD INTO THE MID STATE...WITH
VCTS AT BNA/CSV.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT THU JUL 26 2012/
UPDATE...
00Z TAF DISCUSSION.
AVIATION...
QLCS HAS DEVELOPED FROM N AR TO SW IN AND MOVING SOUTHEASTWARD
TOWARDS MID TN...WITH ISOLATED TSRA DEVELOPING IN FRONT OF THE
LINE AS WELL. LATEST LAPS ANALYSIS SHOWS A STRONG INSTABILITY
AXIS FROM SW TO NE ACROSS THE MID STATE WITH CAPES OF 2500-3000
J/KG...AND HRRR GUIDANCE INDICATES LINE WILL SURVIVE AND AFFECT
CKV AROUND 02Z BUT WEAKEN AS IT APPROACHES BNA AND CSV LATER
TONIGHT. WILL SHOW MAIN TSRA IMPACTS AT CKV THIS EVENING WITH
GUSTS TO 30 KTS AND IFR VIS POSSIBLE...AND STRATIFORM TSRA/SHRA
BEHIND THE MAIN LINE THROUGH THE EARLY MORNING HOURS. LESSER
IMPACTS EXPECTED WITH WEAKENING LINE AT BNA AND CSV WITH VCTS OR
TEMPO TSRA. BREAK IN ACTIVITY EXPECTED FRIDAY MORNING BEFORE
REDEVELOPMENT BY AFTERNOON ACROSS MIDDLE TENNESSEE WITH COLD FRONT
MOVING ACROSS.
PREV DISCUSSION... /ISSUED 623 PM CDT THU JUL 26 2012/
UPDATE...
SEVERE STORMS ASSOC WITH UNSTAB ATM AND H5 TROF DIGGING SOUTH OVR
THE OHVLY. LATEST MODELS DROP ANOTHER S/W TROF IN THE SOUTHERN
PLAINS MOVG SOUTHEAST. THIS SHOULD KEEP STORM ACTIVITY STRONG TO
SEVERE THIS EVENING...AS SYSTEM SPREADS INTO NORTHWEST CORNER OF
MID-TN BTW 8 AND 9 PM.
PREV DISCUSSION... /ISSUED 351 PM CDT THU JUL 26 2012/
DISCUSSION...
CAP ACROSS THE MID STATE IN A HOLDING PATTERN FOR NOW. COULD STILL
SEE SOME ISOL DEVELOPMENT THROUGH THIS EVENING. OTW...A FRONTAL
BOUNDARY IS LOCATED TO OUR NORTH ACROSS CENTRAL IL WITH BETTER
CONVECTION COVERAGE ALONG AND JUST SOUTH OF THIS FEATURE.
FOR TONIGHT...SHOULD SEE A 1-2 PUNCH IN TERMS OF CONVECTION CHANCES.
ISOLATED ACTIVITY IS EXPECTED THROUGH THIS EVENING. THEN...AS THE
AFOREMENTIONED FRONTAL BOUNDARY SINKS SOUTHWARD...A BETTER CHANCE
OF SHOWERS AND TSTMS WILL COMMENCE SOMETIME AROUND MIDNIGHT.
OVERNIGHT CAPE VALUES ARE QUITE IMPRESSIVE AND SINCE GRAPHICAL DEW
POINTS LOOK REASONABLE...STRONG TO PERHAPS SEVERE STORMS WILL BE
POSSIBLE. LATEST 3 HR PRESSURE CHANGE IN SUPPORT OF THE SOUTHWARD
MOVING BOUNDARY.
PRECIP PROBABILITIES WILL NOT BE ALL THAT HIGH TONIGHT AND TUESDAY.
MODELS ARE CONSISTENT WITH A RATHER NARROW RELATIVE DEEP MOISTURE
PROFILE. POPS WILL BE HELD DOWN INTO THE 30-50 PERCENT RANGE TONIGHT
AND FRIDAY.
CAPE VALUES WILL REMAIN ELEVATED THROUGH THE DAY ON FRIDAY. SO
AGAIN...STRONG TO SEVERE STORMS WILL BE POSSIBLE.
DRIER AIR WILL FINALLY WORK INTO THE AREA FRIDAY NIGHT. THIS DRY
PATTERN WILL EXTEND INTO THE FIRST PORTION OF THE EXTENDED FCST.
FOR THE SHORT TERM TEMPS...ABOVE NORMAL TEMPS TO CONTINUE BUT WE
WILL SEE MORE OF A DIURNAL RANGE THIS WEEKEND.
ADDITIONALLY...DEWPOINTS WILL LOWER INTO THE 60S FOR SATURDAY AND
SUNDAY...SO NICE WEEKEND COMING UP.
FOR THE EXT FCST...UPPER HIGH TO HOLD OVER TX AND THIS WILL KEEP
MIDDLE TN UNDER A NW FLOW REGIME. AFTER A DRY PERIOD THIS
WEEKEND...DISTURBANCES AND AN INCREASE IN MOISTURE WILL TRANSLATE
THE PATTERN INTO MORE OF AN ACTIVE NW FLOW. WILL THEREFORE INCLUDE A
CHANCE OF SHOWERS AND TSTMS BEGINNING ON TUESDAY. OTW...TEMPS TO
REMAIN ABOVE NORMAL. STILL A REASONABLE CHANCE THAT THIS JULY WILL
END UP BEING THE 2ND WARMEST ON RECORD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
331 PM CDT FRI JUL 27 2012
.DISCUSSION...
A WEAKNESS IN THE BUILDING HIGH PRESSURE RIDGE ALOFT WILL AFFECT
SE TX TONIGHT AND POSSIBLY DURING THE EARLY TO MID PART OF NEXT
WEEK. OUTFLOW BOUNDARIES FROM THUNDERSTORMS THAT AFFECTED NE TX
AND NW LA EARLIER TODAY SHOULD WORK THEIR WAY INTO THE EASTERN
COUNTIES OF THE FORECAST AREA TONIGHT. THE RAP AND GFS BOTH
INDICATE AT LEAST ISOLATED CONVECTION IS POSSIBLE WITH THE NAM
SHOWING THE RAIN CHANCES JUST TO THE EAST. GIVEN THE WEAKNESS
ALOFT AND THE MODEL OUTPUT...DECIDED TO GO WITH ISOLATED POPS
TONIGHT GENERALLY ALONG AND NORTHEAST OF A LINE FROM AUSTONIO TO
LIBERTY. AS THE WEAKNESS MOVES SLOWLY EASTWARD...ISOLATED SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO LINGER OVER THE COASTAL WATERS
ON SUNDAY.
THE HIGH PRESSURE RIDGE ALOFT WILL BUILD OVER SE TX OVER THE
WEEKEND...AND BRING SOUTHWESTERLY WINDS AND HOT DAYTIME
TEMPERATURES. SOME LOCATIONS MAY REACH TO NEAR 100 ON SATURDAY
AND LIKELY ON BOTH SUNDAY AND MONDAY. THE CENTER OF THE RIDGE IS
FORECAST TO MOVE SLIGHTLY WESTWARD AS THE WEAKNESS DEEPENS
SLIGHTLY AFTER MONDAY. THERE IS SOME UNCERTAINTY AS TO HOW STRONG
THE RIDGE WILL BE AND HOW FAR WEST IT WILL MOVE NEXT WEEK BETWEEN
THE GFS AND ECMWF. BECAUSE OF THIS...RAIN CHANCES WILL STAY LOW
THROUGH WEDNESDAY AND DAYTIME TEMPERATURES WILL REACH AT LEAST
INTO THE MID AND UPPER 90S.
40
&&
.MARINE...
PRESSURE GRADIENT WILL RELAX OVER THE NEXT SEVERAL DAYS LEADING TO
LIGHT WINDS AND LOW SEAS. SHOULD SEE A PROMINENT LANDBREEZE/
SEABREEZE CIRCULATION SET UP THIS WEEKEND. 47
&&
.PREV DISCUSSION... /ISSUED 1225 PM CDT FRI JUL 27 2012/
AVIATION...
MAY SEE ONE OR TWO CELLS POP UP LATER THIS AFTN...BUT NOT WORTH
MENTIONING IN TAFS ATTM. OTHERWISE...VFR THRU MAJORITY OF THE NEXT
24-30+ HOURS. KEPT THE MENTION OF LATE NIGHT/EARLY MORNING MVFR
FOG AT THE SAME NON-METRO TERMINALS THAT HAD IT LAST NIGHT. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 77 98 76 100 77 / 10 10 10 10 10
HOUSTON (IAH) 77 96 77 98 77 / 10 10 10 10 10
GALVESTON (GLS) 82 93 82 92 82 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1206 PM EDT FRI JUL 27 2012
.SYNOPSIS...
SHOWER AND THUNDERSTORM ACTIVITY WILL BE SCATTERED ACROSS THE AREA
THIS AFTERNOON AS A SLOW MOVING COLD FRONT APPROACHES FROM THE
NORTHWEST. THIS COLD FRONT WILL EXIT OUR AREA TO THE EAST BY
SATURDAY AFTERNOON...WITH HIGH PRESSURE BUILDING IN FROM THE GREAT
LAKES FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130 AM...
NEAR FULL SUN ONGOING EAST OF BLUE RIDGE WHICH SHOULD PROMOTE
STRONG INSTABILITY TO FUEL STRONG TO SEVERE STORMS THIS AFTERNOON.
THE STORM PREDICTION CENTER CONTINUES TO MAINTAIN SLIGHT RISK FOR
SEVERE STORMS ALONG AND EAST OF BLUE RIDGE...MAIN THREAT DAMAGING
WINDS.
MORNING RNK SOUNDING WAS NOT OVERLY IMPRESSIVE DUE TO DEBRIS
REMANTS FROM MCS TO OUR NORTH LAST NIGHT...TEMPS ALOFT STILL WARM
AND WINDS WESTERLY. MODIFIED SOUNDING FOR THE AFTERNOON HOWEVER
SUGGESTS A MORE RESPECTIBLE ENVIRONMENT FOR STORM GROWTH...CAPES
2000-3000...AND STEEPER MID LEVEL LAPSE RATES PER COOLING TEMPS
ALOFT COOLING FROM APPROACHING UPPER TROUGH. AS WE TRANSITION
THROUGH THE AFTERNOON ANTICIPATE BACKING OF THE LOWER LEVEL WIND
AHEAD OF THE APPROACHING TROUGH...YIELDING INCREASING CONVERGENCE
ALONG THE BLUE RIDGE. LEE TROUGH SHOULD ALSO STRENGTHEN PER
INTENSE AFTERNOON HEATING FURTHER INCREASING THE CONVERGENCE EAST
OF THE BLUE RIDGE.
BOTH THE RNK WRF AND HRRR SUGGEST INBOUND SHRA/TSRA ACTIVITY FROM WV
WILL BE JOINED BY NEW DEVELOPMENT VCNTY OF BLUE RIDGE AND LEE
TROF. AS SUCH MAY END UP WITH SEVERAL BANDS OR STORM CLUSTERS
WHICH WILL THEN MOVE EAST BOUND TOWARD THE COAST DURING THE LATE
AFTERNOON AND EVENING.
FOR OUR CWA...THE GREATEST INSTABILITY WILL RESIDE OVER OUR
EASTERN COUNTIES...THUS EXPECT TO SEE STRONGEST THUNDERSTORM
ACTIVITY FOR OUR PIEDMONT COUNTIES...MAINLY SOUTH AND EAST OF THE
ROANOKE VALLEY. MODELS HAVE ALL OF THE ACTIVITY CLEARING THE CWA
AROUND SUNSET.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 425 AM EDT FRIDAY...
UPPER ATMOSPHERIC PATTERN WILL CONTINUE TO AMPLIFY THROUGH THE SHORT
TERM AS THE SUBTROPICAL RIDGE GAINS STRENGTH AND AMPLITUDE ACROSS
THE CENTRAL/SOUTHERN PLAINS ONCE AGAIN. THIS WILL LEAD TO ENHANCED
NORTHWEST FLOW ACROSS THE MID-ATLANTIC REGION DURING THE WEEKEND. A
SERIES OF DISTURBANCES IN THE PERSISTENT NW FLOW ALOFT WILL FINALLY
SHIFT THE MAIN UPPER TROUGH AXIS TO THE EAST SIDE OF THE CWA BY LATE
SAT...THEN RESULT IN A GENERALLY QUASI-STATIONARY PATTERN ACROSS THE
U.S. INTO EARLY NEXT WEEK FEATURING A LINGERING UPPER
TROUGH...CENTERED JUST EAST OF THE CWA THROUGH MUCH OF THE PERIOD. A
CONTINUED SERIES OF DISTURBANCES TRACKING IN NW FLOW ON THE BACKSIDE
OF THIS UPPER TROUGH WILL KEEP A FAIRLY ACTIVE PATTERN IN PLACE.
ALTHOUGH THE UPPER PATTERN DOES NOT CHANGE SUBSTANTIALLY THROUGH THE
PERIOD...DAY-TO-DAY CONVECTIVE CHANCES WILL. FOR SAT...THE BEST
LOW-LEVEL AIR MASS HAS SHIFTED EAST OF THE CWA...BUT NOTICEABLY
COLDER AIR ALOFT AND PVA IN AFOREMENTIONED NW FLOW ALOFT WILL
ENHANCE PCPN...ESPECIALLY THAT WHICH IS OROGRAPHICALLY INDUCED
ACROSS THE NORTHERN ALLEGHANYS AND THE SW BLUE RIDGE. FOR SUN...THE
BEST UPPER SUPPORT AND LOW-LEVEL MOISTURE HAS SHIFTED EAST OF THE
REGION...LEAVING THE CWA IN A MORE STABLE...DRIER AIR MASS. AT THIS
POINT...WITH THE MAIN TROUGH AXIS EAST OF THE REGION...HAVE LIMITED
POPS TO JUST THOSE OROGRAPHICALLY AND DIURNALLY INDUCED. BY
MON...NEW DISTURBANCES ORIGINATING IN THE NORTHERN PLAINS/SC CANADA
WILL TRACK TOWARD THE REGION...RESULTING IN A SLOW RETROGRESSION OF
THE UPPER TROUGH. HENCE...EXPECT DIURNAL CONVECTION TO BE ON THE
INCREASE ONCE AGAIN MON...ESPECIALLY ON THE EAST SIDE OF THE
ALLEGHANYS WHERE DEEPER LOW-LEVEL MOISTURE AND SE-S SFC FLOW SHOULD
EXIST.
MAX/MIN TEMPS DURING THE PERIOD SHOULD BE CLOSER TO SEASONAL NORMALS
THAN THE PAST FEW DAYS...BUT LIKELY REMAINING SLIGHTLY AOA NORMALS
WITH 850MB TEMPS STILL IN THE +18-+20C RANGE SAT-SUN. GREATER
INSOLATION...ESPECIALLY SUN...WILL ALSO OFFSET THE SLIGHTLY LOWER
LOW-LEVEL THICKNESSES AND 850MB TEMPS. THE MAIN CHANGE WILL BE
NOTICED WITH SLIGHTLY LOWER DEWPOINTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 425 AM EDT FRIDAY...
THE BLOCKING PATTERN WHICH BECOMES ESTABLISHED DURING THE SHORT TERM
REMAINS IN PLACE THROUGHOUT NEXT WEEK WITH A STRONG UPPER RIDGE
ANCHORED ACROSS IN THE TX/OK/NM REGION...ANOTHER STRONG RIDGE OFF
THE MID-ATLANTIC COAST...AND A GENERAL BROAD UPPER TROUGH ACROSS THE
EASTERN U.S. THIS UPPER TROUGH SLOWLY RETROGRADES THROUGH THE
EXTENDED PERIODS...WHICH SLOWLY RESULTS IN THE CWA TRANSITION FROM
NW FLOW ALOFT AT THE BEGINNING OF THE LONG TERM PERIOD TO A
SOUTHWEST FLOW ALOFT BY THE END OF THE PERIOD. LOW-LEVEL MOISTURE
AND PWATS CONTINUE TO INCREASE...ALL RESULTING IN ENHANCED CHANCES
FOR DIURNAL CONVECTION AND CLOUD COVER. EXPECT SCT-NMRS DIURNAL
CONVECTION THROUGH THE PERIOD. AT THIS POINT...TUE-WED APPEAR TO
OFFER THE BETTER CHCS FOR CONVECTIVE COVERAGE WITH BETTER UPPER
DYNAMICS IN PLACE...BUT GIVEN MODEL UNCERTAINTIES...AT LEAST CHC
POPS WILL REMAIN IN PLACE THROUGHOUT THE ENTIRE PERIOD. THE CLOUD
COVER WILL HOLD MAX TEMPS NEAR OR SLIGHTLY BELOW NORMAL...WHILE MIN
TEMPS WILL REMAIN AOA NORMAL WITH WARM MUGGY NIGHTS.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
AS OF NOON FRIDAY...
ANTICIPATING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP OVER THE MOUNTAINS AND MOVE EAST THROUGH THE PIEDMONT THIS
AFTERNOON. SOME OF THE STORMS COULD BE SEVERE WITH ISOLATED WIND
GUSTS OF 50 KTS. CONDITIONS WILL BE PRIMARILY VFR EXCEPT IN THE
VCNTY OF THE SHRA/TSRA. STORM THREAT GREATEST BETWEEN
2-5PM...DIMINISHING TOWARD SUNSET...SOME VFR DEBIS CLOUDINESS
LINGERING OVERNIGHT TONIGHT. WINDS TODAY WILL BE WESTERLY
GENERALLY 7-10KTS WITH SOME LOW END 16-18KT GUSTS. HIGHER GUSTS
LIKELY IN THE VCNTY OF THE STORMS.
THE MAIN SURFACE COLD FRONT WILL PUSH THROUGH THE FORECAST AREA
ON SATURDAY MORNING AND AFTERNOON. ADDITIONAL SHOWERS AND
THUNDERSTORMS...WITH SUB-VFR CONDITIONS ARE POSSIBLY THROUGH
SATURDAY EVENING.
THE AIR MASS DRIES OUT AND VFR PREVAILS ACROSS THE REGION SATURDAY
NIGHT INTO EARLY MONDAY. RETURN MOISTURE AND RESIDUAL FRONT TO THE
SOUTH WILL LIKELY RESULT IN MORE DIURNALLY DRIVEN CONVECTION
MONDAY INTO TUESDAY...BUT MAINLY VFR OUTSIDE OF AFTERNOON STORMS
AND OVERNIGHT VALLEY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...PM
SHORT TERM...JC
LONG TERM...JC
AVIATION...PM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
714 PM CDT SAT JUL 28 2012
.SHORT TERM...
713 PM CDT SAT JUL 28 2012
CONFIDENCE IS GROWING IN A LATE NIGHT RAIN...ESPECIALLY ALONG AND WEST
OF MISS RIVER.
HAVE BEEN MAKING SOME MINOR CHANGES THROUGH 06Z TONIGHT PER RADAR
AND LATEST 28.21Z RAP AND 28.18Z NAM SUGGEST NARROW BUT POTENT
FRONTOGENESIS IN THE 600-700MB LAYER REMAINS TO THE SOUTHWEST...JUST
WEST OF A KMCW-KDVN LINE. HAVE DECREASED RAIN CHANCES IN NERN IA
AND SERN MN THIS EVENING. GUIDANCE SUGGESTS THIS FRONTOGENESIS SHOULD
WEAKEN AS THE EVENING PROGRESSES...AND THEN A REFOCUSING OF LOW-
LEVEL FORCING OCCURS OVER SWRN MN AHEAD OF SD SHORTWAVE TROUGH
NEAR KABR. 850 MB MOISTURE TRANSPORT BECOMES CONVERGENT IN THE
SOUTHWESTERLY FLOW AHEAD OF THE LOW-LEVEL LOW CENTER /CLOSED LOW/
ALONG A BAROCLINIC ZONE OFFERING SOME ISENTROPIC UPGLIDE TOO.
28.21Z RAP AND 28.18Z NAM BRING THIS FORCING INTO THE FORECAST
AREA AS 09Z APPROACHES...AND THIS LOOKS ON TRACK WITH CURRENT
RAIN FORECAST WEST OF THE MISS RIVER. HAVE TAKEN A SLIGHT STEP
EAST WITH RAIN CHANCES LATE TONIGHT TO JUST OVER THE MISS RIVER
WITH THOSE SIGNALS. 28.18Z NAM QPF SEEMS A BIT INTENSE AND HRRR
SUGGESTS COVERAGE WILL BE MORE SCT FOR SHRA/TSRA. SO...STILL SOME
QUESTIONS ON COVERAGE OF SHRA. STILL HAVE TSRA CHANCES AS THERE IS
200-500 J/KG MUCAPE IN FORCING AREA. HAVE ALSO SLIGHTLY BUMPED
RAIN CHANCES UP IN THE WEST. IF SIGNALS CONTINUE WITH NEW
GUIDANCE/RAOBS/PROFILERS IN THE NEXT HOURS...WILL BE INCREASING
MORNING RAIN CHANCES TOO ALONG MISS RIVER MORE. WOULD THINK RAIN WILL
TAPER AND SHIFT OFF TO THE SOUTHEAST IN THE LATE MORNING.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
305 PM CDT SAT JUL 28 2012
BOTH THE 28.12Z ECMWF AND GFS CONTINUE THE NORTHWEST FLOW REGIME OVER
THE AREA THROUGH THE PERIOD. THIS FLOW WILL KEEP TEMPERATURES NEAR
SEASONAL NORMALS. SEVERAL WAVES LOOK TO IMPACT THE REGION AND
SOMEWHAT DIFFICULT TO TIME. THE FIRST LOOKS TO DROP ACROSS THE AREA
WEDNESDAY THROUGH THURSDAY AND THE SECOND ONE FRIDAY NIGHT INTO
SATURDAY.
&&
.AVIATION...TONIGHT AND SUNDAY
713 PM CDT SAT JUL 28 2012
HAVE TAKEN A BIT MORE PESSIMISTIC STEP IN THE TAF FORECASTS AS
CONFIDENCE GROWS THAT RAIN WILL BE MOVING IN AROUND THE 09-12Z
TIME FRAME. TOUGH FORECAST FOR CIG/VSBY AS LOW-LEVELS ARE SOMEWHAT
DRY...BUT LIFT AND FORCING FOR RAIN LOOK PRETTY GOOD. MODEL
GUIDANCE WOULD SUGGEST AN IFR EVENT AT KRST FOR SATURDAY MORNING...BUT
FEEL THAT MAY BE A BIT AGGRESSIVE. THEREFORE...INTRODUCED MVFR AT
KRST AFTER A FEW HOURS OF SHRA IN THE MORNING AS THE LOW- LEVELS
SATURATE. RAIN THEN SHOULD SHIFT OFF TO THE SOUTHEAST WITH
CIG/VSBY IMPROVEMENT AFTER 18Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 PM CDT SAT JUL 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...RABERDING
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
308 PM CDT FRI JUL 27 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COMPACT UPPER
SHORTWAVE MOVING EAST OVER NORTHERN LAKE MICHIGAN EARLY THIS
AFTERNOON. SCATTERED TO NUMEROUS SHOWER ACTIVITY CONTINUES TO
DEVELOP AND ROTATE AROUND THE SHORTWAVE ACROSS MUCH OF NORTHEAST AND
CENTRAL WISCONSIN. NORTH-CENTRAL WISCONSIN HAS BEEN THE LONE DRY
SPOT TODAY AND CLEARING IS BEGINNING TO WORK INTO VILAS COUNTY FROM
THE NORTH. HIGH PRESSURE RESIDES OVER THE NORTHERN MISSISSIPPI
VALLEY AND THE DAKOTAS WHERE MOSTLY CLEAR TO PARTLY CLOUDY
CONDITIONS ARE OCCURRING. THE MAIN FORECAST CONCERNS ARE TIMING THE
END OF THE SHOWER ACTIVITY AND FOG/TEMPS.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE TO THE EASTERN GREAT LAKES
TONIGHT WHILE HIGH PRESSURE BUILDS INTO THE REGION IN ITS WAKE.
PLENTY OF LOW LEVEL MOISTURE UPSTREAM ALL THE WAY WEST TO MINNESOTA
AND DRY AIR ADVECTION IS WEAK...SO IT MAY TAKE AWHILE FOR CLOUDS TO
CLEAR. SHOULD SEE THE CLEARING WORK FROM NW TO SE THROUGH THE NIGHT
THOUGH. HAVE INCREASED SKY COVER THIS EVENING BUT STILL TAKE SKY
CONDITIONS MOSTLY CLEAR OVERNIGHT. AFTER SEVERAL ROUND OF RAINFALL
THE PAST FEW DAYS...MOIST SOIL CONDITIONS WILL BE SUPPORTIVE FOR FOG
OVERNIGHT. WILL ADD AREAS OF DENSE FOG TO THE FORECAST FOR
NORTH-CENTRAL WISCONSIN. LOWS RANGING FROM THE UPPER 40S NORTH TO
AROUND 60 SOUTH.
SATURDAY...HIGH PRESSURE WILL BE OVER THE AREA AND WILL LEAD TO DRY
CONDITIONS. THE 12Z NAM IS MORE BULLISH IN KEEPING THE LOW LEVEL
MOISTURE AROUND FOR TOMORROW...WHICH SHOULD LEAD TO A DECENT CU
FIELD DEVELOPING BY LATE MORNING. UPSTREAM OBS SUPPORT THIS OVER
MINNESOTA SO WILL PORTRAY PARTLY CLOUDY CONDITIONS FOR THE
AFTERNOON. HIGHS WILL BE SEASONABLE AROUND THE UPPER 70S TO LOWER
80S.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY.
THE PRIMARY CONCERNS DURING THIS PART OF THE FORECAST ARE TIMING OF
UPPER LEVEL SHORT WAVES AND ASSOCIATED PRECIPITATION CHANCES.
A CLOSED 500MB LOW IN THE VICINITY OF HUDSON BAY AND A WEAK RIDGE
OVER THE CENTRAL/WESTERN CONUS WILL KEEP THE REGION IN WEST-
NORTHWEST FLOW ALOFT. MEDIUM RANGE MODELS WERE NOT IN THE BEST OF
AGREEMENT...BUT DID HAVE SOME QPF FORECAST IN/AROUND THE AREA
SATURDAY NIGHT AND SUNDAY. SHORT WAVE ENERGY AND A WEAK SURFACE
BOUNDARY MOVING INTO WISCONSIN FROM THE NORTH WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS ON TUESDAY. SURFACE HIGH PRESSURE
SHOULD KEEP TUESDAY NIGHT DRY BEFORE MODELS BRING THE NEXT SHORT
WAVE AND SURFACE BOUNDARY INTO THE FORECAST AREA...KEEPING A
CHANCE OF SHOWERS AND STORMS AROUND THROUGH THURSDAY. SURFACE HIGH
PRESSURE BUILDING IN BEHIND THE DEPARTING FRONT SHOULD KEEP
FRIDAY DRY.
DO NOT REALLY SEE A REASON FOR TEMPERATURES TO WARM INTO THE 90S
IN THE NEAR FUTURE. LOOKS LIKE READINGS SHOULD BE CLOSER TO
SEASONAL NORMALS.
&&
.AVIATION...UPPER LEVEL LOW PRESSURE WILL EXIT THE REGION BY EARLY
THIS EVENING. WILL TAKE SOME TIME FOR THE LOW LEVELS TO DRY OUT AND
NOT ENTIRELY SURE THAT SKIES WILL CLEAR THIS EVENING. BUT GUIDANCE
STILL SUPPORTS THIS SO DID NOT MAKE TOO MANY CHANGES TO THE FORECAST
THIS EVENING ONWARD. STILL THINK WILL SEE SCT-NMRS SHOWERS AND
ISOLD THUNDERSTORMS OVER THE FOX VALLEY THROUGH MID TO LATE
AFTERNOON. COVERAGE OF SHOWERS MORE SPOTTY EVERYWHERE ELSE.
CLEARING SKIES AND LIGHT WINDS LATE TONIGHT WILL SUPPORT AREAS OF
FOG DEVELOPING. SHOULD SEE DENSE FOG AT TIMES WITHIN THE LOW LYING
AREAS AND COLD SPOTS. HIGH PRESSURE OVER THE REGION TOMORROW...BUT
AMPLE LOW LEVEL MOISTURE WILL LEAD TO CU BUILD UP BY MIDDAY.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/MG
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1150 PM MDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 510 PM MDT SAT JUL 28 2012
ISOLATED TO SCATTERED CONVECTIVE ACTIVITY IN THE VICINITY OF A
SURFACE TROUGH SHOULD CONTINUE MOVING TO THE EAST AND DISSIPATE
THROUGH THE EVENING AS THE TROUGH ALSO MOVES FURTHER SOUTH ACROSS
THE FORECAST AREA OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 224 PM MDT SAT JUL 28 2012
WV IMAGERY AND RUC H5 ANALYSIS SHOW STRONG RIDGE EXTENDING FROM THE
WESTERN US TO THE CENTRAL MISSISSIPPI RIVER VALLEY WITH A 597 HEIGHT
CENTER OVER NE OKLAHOMA. A PLUME OF MONSOONAL MOISTURE CONTINUES TO
ADVECT NORTH AND EAST ALONG THE WESTERN EXTENT OF THE RIDGE WITH
SEVERAL WEAK SHORTWAVE TROUGHS MOVING INTO THE TRI-STATE AREA FROM
THE WEST. AT THE SURFACE A COLD FRONT HAS STALLED OVER THE CWA AND
WILL ACT AS THE MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT THROUGH THE
NEXT FEW DAYS.
EARLY THIS AFTERNOON ISOLATED THUNDERSTORMS HAVE ALREADY DEVELOPED
ACROSS THE NE CWA NEAR MCCOOK ALONG THE FRONT WITH CUMULUS FURTHER
SOUTH AND EAST. RUC SOUNDINGS CONTINUE TO SHOW INVERTED-V TYPE
SOUNDINGS ALONG WITH DCAPE VALUES AROUND 1400 J/KG OR GREATER ACROSS
THE EASTERN PART OF THE CWA...WHICH SUPPORTS A THREAT FOR STRONG
DAMAGING WINDS WITH ANY THUNDERSTORMS THAT DEVELOP. PWAT VALUES ARE
ACTUALLY PRETTY GOOD WITH VALUES AROUND 1.4-1.5 AS A RESULT OF
MONSOONAL MOISTURE ADVECTING INTO THE MID LEVELS...SO THUNDERSTORM
COULD BE GOOD RAIN PRODUCERS THOUGH STORM MOTIONS AROUND 20KT SHOULD
KEEP FLASH FLOOD THREAT LIMITED. STORM THUNDERSTORM ACTIVITY THIS
EVENING SHOULD BE TIED TO DIURNAL PROCESSES WITH ACTIVITY ENDING
SHORTLY AFTER SUNRISE.
SUNDAY...THERE WILL BE VERY LITTLE CHANGE IN THE PATTERN AS THE
STATIONARY FRONT LINGERS OVER THE CWA...AND THE RIDGE REMAINS IN
PLACE. THUNDERSTORMS SHOULD REDEVELOP BY THE AFTERNOON WITH THE
FRONT AGAIN ACTING AS THE MAIN FOCUS FOR INITIATION. NAM SOUNDINGS
SHOW EVEN BETTER MID LEVEL MOISTURE SUNDAY AFTERNOON WITH PWAT
VALUES IN EXCESS OF 1.6...WHICH IS ANOMALOUSLY HIGH FOR THIS TIME
OF YEAR. CONSIDERING THAT AND VERY LIGHT STORM MOTIONS ON SUNDAY
IN THE ABSENCE OF ANY FLOW ALONG THE STATIONARY FRONT...THERE WILL
BE AN INCREASED THREAT OF FLASH FLOODING WITH ANY THUNDERSTORMS
THAT DO DEVELOP. COVERAGE WILL BE A QUESTION...SO I AM NOT
CONFIDENT ENOUGH TO ISSUE A FLASH FLOOD WATCH FOR SUNDAY
AFTERNOON/EVENING DURING THIS FORECAST CYCLE...HOWEVER THIS SHOULD
BE WATCHED GOING FORWARD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MDT SAT JUL 28 2012
UPPER RIDGE OVER THE SOUTHERN PLAINS WILL DRIFT WEST SOUTHWESTWARD
DURING THIS PERIOD. FAST MOVING SHORTWAVE TROUGHS RIDING THE RIDGE
MIGHT BE CLOSE ENOUGH TO PROVIDE WEAK LIFT FOR ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS...BUT CONFIDENCE IS LOW AND DO NOT
WARRANT MORE THAN A SLIGHT TO LOW CHANCE MENTION. TEMPERATURES
WILL CONTINUE TO BE ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1147 PM MDT SAT JUL 28 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT KMCK AND KGLD.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO MOVE INTO THE AREA
FROM THE WEST DURING THE AFTERNOON AND EVENING. HAVE INTRODUCED A
PROB30 GROUP INTO THE KGLD TAF BETWEEN 22Z-04Z SUNDAY
EVENING...BUT HAVE LEFT KMCK WITHOUT A MENTION OF THUNDERSTORMS
SINCE PROBABILITIES OF THUNDERSTORM DEVELOPMENT ARE LESS FURTHER EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...024
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
419 AM EDT SUN JUL 29 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 132 AM EDT SUN JUL 29 2012
VFR CONDITIONS TO CONTINUE THROUGH THE FORECAST PERIOD. LIGHT AND
VARIABLE WINDS OVERNIGHT WILL BECOME SOUTH AT LESS THAN 10 KNOTS
AFTER SUNRISE AS SFC PRESSURE GRADIENT BEGINS TO SLOWLY TIGHTEN UP
AHEAD OF A WEAK LOW PRESSURE SYSTEM THAT WILL MOVE INTO THE REGION
ON MONDAY. THIS FEATURE IS EXPECTED TO PRODUCE WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS OVER KIWD AND KCMX AFTER 02Z MONDAY BUT
THE PROBABILITIES ARE LOW ENOUGH AT THIS TIME TO WARRANT NOT
INCLUDING A MENTION IN THE FORECASTS FOR THOSE SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
415 AM CDT SUN JUL 29 2012
.DISCUSSION...
SHORT WAVE NEAR WILLMAR THIS MORNING HAS DRIVEN SHOWERS ACROSS THE
AREA THIS PAST NIGHT. ELEVATED SHOWERS ACROSS WRN WI OVER TO THE
NRN TWIN CITIES ARE WITHIN A ZONE OF WEAK FGEN/ISENTROPIC LIFT
AROUND H6...ACTIVITY WEST OF THE CITIES IS ASSOCIATED WITH THE
SHORTWAVE...WHILE MOST ROBUST AREA OF CONVECTION ACROSS SOUTH
CENTRAL MINNESOTA IS ON THE NOSE OF THE LLJ. THE RAP SHOWS THIS
UPPER WAVE REACHING LA CROSSE BY 15Z...WITH ASSOCIATED FORCING
MOVING TO THE SOUTHEAST THROUGH THE REST OF THE MORNING. SRN MN
CONVECTION WILL CERTAINLY CONTINUE TO FOCUS BRUNT OF PRECIP TO THE
SOUTH...BUT SHOULD CONTINUE TO SEE LIGHT SHOWERS FOLLOW THE H7/H5
LOW SE ACROSS THE AREA THIS MORNING...WITH A MAJORITY OF RAIN
FALLING ALONG AND SOUTH OF I-94. BASED ON RAP TIMING OF THE
SHORTWAVE AND REFLECTIVITY FORECASTS FROM MOST CAMS...EXPECT MOST
OF THIS PRECIP TO BE OUT OF THE MPX CWFA BY 15Z. IN THE RAINS
WAKE...SKIES WILL BE CLEARING OUT FROM WEST TO EAST. H85 TEMPS
WILL RANGE FROM AROUND +22C WEST TO +16 EAST...WHICH SHOULD ALLOW
FOR LOWER 90S TO LOWER 80S FOR HIGHS RESPECTIVELY.
FOR TONIGHT...STRONG WAVE CURRENTLY SPINNING ACROSS SRN SASK WILL
RUN ALONG THE MN/ONTARIO BORDER...DRIVING A COLD FRONT INTO NRN
MN. CAMS AND SREF PROBS ALL SIMILAR WITH DEVELOPING SCT STORMS
ALONG THE FRONT THIS AFTERNOON FROM ERN NODAK INTO NW MN. THIS
FRONT WILL BE MOVING INTO CENTRAL MN BY 12Z MONDAY...SO INTRODUCED
SOME SMALL POPS ACROSS CENTRAL MN LATE TONIGHT TO ACCOUNT FOR
THAT. DURING THE DAY MONDAY...THIS FRONT WILL DROP ACROSS THE
AREA...EXITING THE S/SE MPX CWFA BETWEEN 21Z AND 00Z. BEST FLOW AT
H85 AND CONVERGENCE ALONG THE BOUNDARY STILL PEGGED TO BE ACROSS
THE U.P. OF MICH INTO NRN WI...WHERE GREATEST POTENTIAL FOR STORMS
WILL EXIST. CONTINUED A NARROW RIBBON OF SLIGHTS ALONG THE FRONT
MONDAY AFTERNOON WITH THE NAM ADVERTISING 2-3000 J/KG OF MUCAPE
ALONG THE FRONT. GIVEN THE FRONTS EXPECTED MOVEMENT...DID TRIM
BACK HOW FAR NORTH POPS ARE MENTIONED MONDAY AFTERNOON. ALSO LOOKS
WARM AGAIN MONDAY...WITH H85 TEMPS WARMING INTO THE 20S C FOR MOST
OF THE AREA...CONTINUED TO ADVERTISE UPPER 80S TO LOWER 90S HIGHS
MONDAY AFTERNOON...WITH 90S CREEPING UP TO ABOUT I-94.
FOR THE REST OF THE FORECAST...WILL BE REMAINING NORTH OF THE MAIN
UPPER RIDGE...WELL WITHIN THE JET STREAMS TERRITORY. STILL LOOKING
AT TWO POTENTIAL ACTIVE PERIODS IN THE TUESDAY THROUGH SUNDAY
TIMEFRAME. THE FIRST WILL BE ANOTHER WEAK NW FLOW WAVE THE MODELS
SHOW CRESTING THE RIDGE WEDNESDAY INTO WEDNESDAY NIGHT...SENDING A
VERY WEAK BOUNDARY ACROSS THE REGION. LIKE MONDAYS FRONT...H85
FLOW WILL BE LACKING WITH THE WEDNESDAY WAVE...AND PRECIP CHANCES
ARE LOOKING SCANT AT BEST WITH THIS WAVE...SO CONTINUED TO CAP
POPS AT 40 PERCENT...WITH BEST CHANCES RUNNING ACROSS CENTRAL MN
INTO WRN WI...WHICH IS WHERE THE ECMWF SHOWS THE SRN END OF A LLJ
WORKING THROUGH.
SHOULD SEE ANOTHER BREAK FROM THE PRECIP ACROSS THE AREA
THURSDAY...BEFORE A MORE SIGNIFICANT UPPER WAVE MOVES ACROSS THE
UPPER MS VALLEY SOMETIME ON FRIDAY /ECMWF AND GEM/ OR SATURDAY
/GFS/. ECMWF IS MOST AGGRESSIVE WITH THE WAVE...BRING A NEUTRAL TO
NEG TILTED TROUGH THROUGH...WITH THE GFS SHOWING A WEAKER
POSITIVELY TILTED TROUGH WORKING THROUGH SATURDAY. GIVEN TIMING
DIFFERENCES...BLENDING PROCEDURE ENDED UP SMEARING CHANCE POPS
ACROSS BOTH DAYS. HOWEVER...DESPITE THE TIMING DIFFERENCES...BOTH
THE GFS AND ECMWF SHOW THIS FRONT PACKING QUITE A PUNCH IN TERMS
OF COOLER/DRIER AIR BEHIND IT...WITH BOTH ADVERTISING A 1020 MB
HIGHS SETTLING IN BEHIND THIS SYSTEM. TILL THEN THOUGH...HIGHS IN
THE MID 80S TO LOWER 90S WILL BE THE NORM.
.CLIMATE...
QUICK CHECK THROUGH THE CLIMATE DATA FOR THE TWIN CITIES FOR
NUMBER OF DAYS IN A MONTH WHERE HIGHS WERE BELOW 80 SHOWS THAT
THERE HAS NEVER BEEN A MONTH IN THE TWIN CITIES WHERE THERE WAS
NOT AT LEAST ONE DAY WITH A HIGH LESS THAN 80 /JULY OF 1936 AND
1916 BOTH HAD ONE SUB 80 DEGREE DAY/. TO THIS POINT...THE
"COLDEST" HIGH THIS MONTH WAS AN 80 ON THE 27TH. BASED ON CURRENT
FORECAST...THIS JULY LOOKS LIKE IT WILL BE THE FIRST MONTH IN
RECORDED HISTORY FOR THE TWIN CITIES WHERE WE FAILED TO SEE AT
LEAST ONE DAY LESS THAN 80. THE LAST SUB 80 HIGH WAS BACK ON JUNE
25TH.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN CONCERN WILL BE STORMS LATE TONIGHT. ELEVATED INSTABILITY
ARCING FROM WEST CENTRAL MN INTO WESTERN WISCONSIN SO HAVE
MENTIONED THUNDER FROM AXN/STC TO RNH/EAU. WILL KEEP THUNDER GOING
FOR JUST TWO OR THREE HOURS AT THESE SITES BUT THE CONCERN WILL BE
FOR MORE DEVELOPMENT. NOT MUCH OF A LOW LEVEL JET IN THIS AREA SO
HAVE TRIED TO KEEP THE THUNDER THREAT AT THOSE LOCALES LIMITED TO
JUST THOSE FEW HOURS. CONFIDENCE A LITTLE LESS THAN AVERAGE ON
THIS THOUGH.
OTHER AREA OF STORMS IN SERN SD INTO SRN MN. INFLUENCE OF LOW
LEVEL JET MORE SIGNIFICANT IN THIS AREA. RWF COULD SEE THUNDER
MUCH OF THE NIGHT ONCE IT ARRIVES AFTER 07Z.
FOG WILL ALSO BE A CONCERN WITH HUMID BOUNDARY LAYER AND LIGHT
WINDS. ONCE PRECIP ENDS SUNDAY AROUND 15Z...SHOULD SEE JUST
SCATTERED CLOUDS WITH PLENTY OF SUBSIDENCE BEHIND SHORT WAVE.
KMSP... SOME THUNDER THREAT LATE TONIGHT BUT WILL NOT BE SHOCKED
IF NORTHERN ARC OF STORMS STAYS NORTH WHILE SWRN STORMS STAY IN
SOUTHERN MN. I.E. SOME POTENTIAL FOR KMSP TO BE BETWEEN AREAS BUT
STILL NEED TO MENTION THUNDER FOR A COUPLE HOURS SINCE LOW LEVEL
JET DOES HAVE A BRIEF TIME WHEN IT REACHES FARTHER NORTH TOWARD KMSP.
CONFIDENCE LOW ON WHETHER THERE WILL BE THUNDER. ONCE SHORT WAVE
GOES BY... SKY SHOULD BE MOSTLY CLEAR THE REST OF SUNDAY AND
SUNDAY NIGHT.
//OUTLOOK
MONDAY... BRIEF MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR EXPECTED.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/TDK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
430 AM CDT SUN JUL 29 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERNS LIE WITH PRECIPITATION CHANCES...AND TEMPERATURES.
BEEN LITTLE OVERALL CHANGE IN THE UPPER LEVEL PATTERN ACROSS THE
REGION...WITH SATELLITE AND PROFILER DATA SHOWING IT REMAINING
DOMINATED BY UPPER LEVEL HIGH PRESSURE/RIDGING CENTERED JUST WEST
OF THE CWA. THIS LEAVES NORTHWESTERLY FLOW IN PLACE...WITH A
DISTURBANCE SHIFTING SOUTHEAST THIS MORNING...RIDING AROUND THE
EDGE OF THE RIDGE. CONTINUING TO SEE A FEW SHOWERS/THUNDERSTORMS
LINGER IN FAR SWRN PORTIONS OF THE CWA EARLY THIS MORNING
RESULTING FROM THIS DISTURBANCE...BUT EXPECT THEM TO EXIT THE CWA
OVER THE NEXT COUPLE HOURS. SEEING A WEAK SURFACE PATTERN IN PLACE
OVER THE CWA...BRINGING LIGHT AND VARIABLE WINDS EARLY THIS
MORNING...THOUGH A WEAK BOUNDARY IS IN PLACE JUST SOUTH OF THE
CWA.
FOR TODAY AND TONIGHT...NO SIGNIFICANT CHANGES WERE MADE TO THE
INHERITED FORECAST. KEPT THE FIRST HALF THE DRY QUIET...WITH
THUNDERSTORM CHANCES RETURNING DURING THE LATE AFTERNOON AND INTO
THE OVERNIGHT HOURS. MODELS NOT IN TOO BAD OF AGREEMENT SHOWING
THE SURFACE BOUNDARY REMAINING NEAR/JUST SOUTH OF THE CWA
THROUGH THE DAYTIME HOURS...AND AS ANOTHER WEAK UPPER LEVEL
DISTURBANCE LOOKS TO ROUND THE EDGE OF THE RIDGE AND MOVE INTO THE
REGION...THUNDERSTORM CHANCES WILL INCREASE. TIMING/OVERALL
COVERAGE REMAINS UNCERTAIN...LITTLE MORE DIFFERENCE BETWEEN
MODELS...NAM CONTINUES TO SHOW AN EARLIER ONSET OF ACTIVITY...VS
OTHERS LIKE THE 06Z HRRR WHICH IS QUIET THRU 21Z...AND THE 00Z 4KM
WRF WHICH SHOWS VERY LITTLE GOING ON AT ALL. BECAUSE OF THESE
DIFFERENCES KEPT POPS THOUGH TONIGHT LOW. COULD SEE A FEW
THUNDERSTORMS ON THE STRONG SIDE...BUT WITH DEEPER LAYER SHEAR
AGAIN ON THE WEAKER SIDE...CHANCES FOR SEVERE WEATHER IS LOW.
AS FAR AS TEMPERATURES GO...WITH THE MORE EASTERLY COMPONENT TO
THE WINDS /ESP ACROSS SC NEB/ STILL EXPECTED...AGAIN MADE FEW
CHANGES. MID/UPPER 90S ARE IN PLACE ACROSS THE NORTH...WITH LOWER
100S POSSIBLE ACROSS NC KS. ENDED UP ISSUING A HEAT ADV FOR NC KS
THIS AFTERNOON...WHERE POTENTIAL FOR HEAT INDEX VALUES NEAR 105
LIES...WITH TEMPS NEAR/JUST ABOVE 100 POSSIBLE AND HIGHER
DEWPOINTS EXPECTED AS THAT AREA SITS NEAR/JUST NORTH OF THE SFC
FRONT. CERTAINLY NOT A SLAM DUNK ADVISORY...A COUPLE OF THINGS
COULD POTENTIALLY MESS UP THE FORECAST HIGHS IN NC KS...SUCH AS
EVEN HIGHER DEWPOINTS THAN CURRENTLY FORECAST /SOME DATA SHOWS
DPTS CLOSER TO THE MID TO UPPER 60S VS THE NEAR 60
FORECAST/...AND/OR HIGHER CLOUD COVER THAN WHAT IS CURRENTLY
FORECAST DURING THE PEAK OF THE AFTERNOON. DECIDED TO GO WITH THE
AREA THAT HAD THE BEST POTENTIAL TO MEET CRITERIA...ALSO THINKING
THE AFFECTS OF ANY THUNDERSTORM DEVELOPMENT WOULD HOLD OFF UNTIL
LATER IN THE AFTERNOON.
GETTING INTO MONDAY AND TUESDAY...AGAIN SEE LITTLE CHANGE IN THE
OVERALL UPPER LEVEL PATTERN...AND CONFIDENCE IN PRECIPITATION
CHANCES REMAINS ON THE LOW SIDE. THE CWA REMAINS UNDER THE
INFLUENCE OF THAT UPPER LEVEL RIDGE...BUT IT DOESNT EXTEND FAR
ENOUGH NORTH TO KEEP US OUT OF THE WAY OF ANY WEAK DISTURBANCE
MAKING THEIR WAY AROUND THE EDGE OF THE RIDGE. ALONG WITH THE
POTENTIAL FOR DISTURBANCES MOVING THROUGH...MODELS NOT IN TOO BAD
OF AGREEMENT SHOWING THIS LINGERING SURFACE BOUNDARY GENERALLY
NEAR/SOUTH OF THE NEB/KS STATE LINE. THOUGH THERE ARE POPS IN
PLACE THROUGH TUESDAY NIGHT...CERTAINLY DONT WANT TO GIVE OFF THE
IMPRESSION THAT THERE ARE GOOD/WIDESPREAD POSSIBILITIES THE ENTIRE
TIME. THE ISSUE IS THAT AT EVEN THIS POINT...JUST A DAY OR TWO
OUT...THERE IS STILL ENOUGH UNCERTAINTY WITH THE TIMING/PLACEMENT
OF THESE DISTURBANCES AND ASSOCIATED PRECIP CHANCES THAT NAILING
DOWN MORE SPECIFIC DETAILS...INCREASING OR REMOVING POPS FOR
PARTICULAR LOCATIONS...IS DIFFICULT...BUT AT LEAST THE CHANCES ARE
THERE. FORECAST HIGHS FOR MONDAY REMAIN GENERALLY IN THE LOWER/MID
90S...WITH TUESDAY IN THE MID/UPPER 90S.
.LONG TERM...WEDNESDAY THROUGH SATURDAY.
CONCERNS FOR THE TERM PERIOD AGAIN FOCUS ON THUNDERSTORM CHANCES
AND NUMEROUS SHORT WAVE PERTURBATIONS AROUND THE UPPER LEVEL
RIDGE. OTHERWISE NO CHANGES WERE MADE TO THE PREVIOUS FORECAST.
BEGINNING THE LONG TERM PERIOD...THE UPPER LEVEL RIDGE REMAINS
STATIONARY ACROSS PORTIONS OF TEXAS AND OKLAHOMA...FLANKED BY TWO
UPPER LEVEL TROUGHS ON EITHER COAST. THROUGHOUT THE PERIOD...THE
RIDGE SLOWLY BEGINS TO BREAK DOWN AS THE WESTERNMOST TROUGH
CONTINUES TO SHIFT EASTWARD ACROSS CANADA. AS SUCH...THE PEAK OF
THE RIDGE FLATTENS OUT ENOUGH THAT THE PLAINS REMAIN IN PERFECT
POSITION FOR ANY UPPER LEVEL SHORT WAVE THAT PASSES BY. ALTHOUGH
THERE REMAINS MANY DISCREPANCIES ON BOTH UPPER LEVEL FEATURES AND
SURFACE FEATURES AMONG THE LONG TERM MODELS...IT IS BECOMING MORE
AND MORE APPARENT AND SUGGESTED BY THE ALL BLEND MODELS THAT THERE
IS A POSSIBILITY OF AT LEAST SOME PRECIPITATION IN THE LONG TERM.
WHILE IT REMAINS QUITE TOUGH TO PINPOINT EXACTLY WHEN AND WHERE
THESE SHOWERS WILL OCCUR...WAS NOT CONFIDENT ENOUGH TO PULL ALL
POPS COMPLETELY OR LEAVE SLIGHT CHANCES IN EVERY PERIOD AS
SUGGESTED BY ALL BLENDS. PER NEIGHBOR COLLABORATION AND MODELS
INDICATIONS OF THE PRESENCE OF SHORT WAVES AND SURFACE BOUNDARIES
ACROSS THE REGION...CONTINUED WITH SLIGHT CHANCES BOTH WEDNESDAY
AFTERNOON...THURSDAY AND FRIDAY.
REGARDING TEMPERATURES IN THE LONG TERM...EXPECTING WARM
TEMPERATURES TO LAST THROUGH THE PERIOD...ALTHOUGH NOT QUITE HAS
HOT AS PREVIOUS WEEKS...CONTINUED WITH 90S TO NEAR 100 ACROSS
THE AREA. CLOUD COVER AND PRECIPITATION CHANCES COULD CERTAINLY
COME INTO QUESTION AND REDUCE HIGHS JUST SLIGHTLY. ALSO CONFIDENCE
REMAINS LOW FOR TEMPERATURES ON SATURDAY. THE GFS SOLUTION AND THE
ECWMF SOLUTION REMAIN COMPLETELY OPPOSITE EACH OTHER....WITH THE
GFS DRAGGING A COLD FRONT THROUGH THE REGION AND THE ECMWF
SUGGESTS A HIGH OVER THE AREA.
&&
.AVIATION...06Z KGRI TAF. AS SURFACE LOW PRESSURE CONTINUES TO
SPIN ACROSS WESTERN KANSAS...SURFACE HIGH PRESSURE WILL GRAZE
NORTHERN PORTIONS OF NEBRASKA TODAY. AS A RESULT...LIGHT AND
VARIABLE WINDS WILL GRADUALLY SHIFT TO THE NORTHEAST THIS MORNING
BEFORE TURNING EASTWARD BY THE END OF THE PERIOD. WHILE A FEW
SCATTERED TO EVEN BROKEN CLOUD DECK WILL APPEAR AT TIMES
THROUGHOUT THE PERIOD...EXPECTING VFR CONDITIONS TO CONTINUE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
FOR KSZ005>007-017>019.
&&
$$
SHORT...ADO
LONG/AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1218 AM CDT SUN JUL 29 2012
.AVIATION...06Z KGRI TAF. AS SURFACE LOW PRESSURE CONTINUES TO
SPIN ACROSS WESTERN KANSAS...SURFACE HIGH PRESSURE WILL GRAZE
NORTHERN PORTIONS OF NEBRASKA TODAY. AS A RESULT...LIGHT AND
VARIABLE WINDS WILL GRADUALLY SHIFT TO THE NORTHEAST THIS MORNING
BEFORE TURNING EASTWARD BY THE END OF THE PERIOD. WHILE A FEW
SCATTERED TO EVEN BROKEN CLOUD DECK WILL APPEAR AT TIMES
THROUGHOUT THE PERIOD...EXPECTING VFR CONDITIONS TO CONTINUE.
&&
.PREV DISCUSSION... /ISSUED 656 PM CDT SAT JUL 28 2012/
UPDATE...IT WAS A DIFFICULT CALL ON WHETHER TO GO WITH A SEVERE
THUNDERSTORM WATCH THIS EVENING AND IT WAS DISCUSSED AT LENGTH
WITH SEVERAL SURROUNDING OFFICES. CONVECTION THUS FAR HAS BEEN
RATHER MARGINAL ALTHOUGH A FEW STORMS HAVE SHOWN RECENT SIGNS OF
STRENGTHENING AND THE ENVIRONMENT IS MORE SUPPORTIVE THAN WE HAVE
SEEN FOR SOME TIME WITH DEEP LAYER SHEAR VALUES OF OVER 50 KTS
ACROSS OUR NORTH. THESE ARE VERY GOOD SHEAR VALUES FOR THIS TIME
OF YEAR. ACROSS OUR SOUTH THE SHEAR IS MUCH WEAKER AT AROUND 20
KTS...BUT THE STEEP LAPSE RATES AND INVERTED V SOUNDINGS ARE
INDICATIVE OF AN ENHANCED WIND THREAT ACROSS KANSAS ZONES AND
PORTIONS OF SOUTHERN NEBRASKA. THERE IS ALSO PLENTY OF CAPE WITH
MLCAPE VALUES RANGING FROM 1500 J/KG ACROSS KANSAS TO 2500 J/KG
OVER NEBRASKA. ULTIMATELY IT WAS DECIDED TO GO WITH A SEVERE
THUNDERSTORM WATCH THROUGH 1 AM.
AVIATION...00Z KGRI TAF. THUNDERSTORMS HAVE DEVELOPED ACROSS
SOUTH CENTRAL NEBRASKA AND COULD MOVE INTO THE KGRI VICINITY.
STILL TOO EARLY TO TELL IF ONE WILL DIRECTLY HIT KGRI OR NOT. SO
FAR THE ACTIVITY IS FAIRLY ISOLATED AN THUS HAVE ONLY INCLUDED
VICINITY WORDING IN THE TAF. THE WIND WILL BE LIGHT OUTSIDE OF
THUNDERSTORMS...BUT COULD BE VERY GUSTY SHOULD A THUNDERSTORM NEAR
THE AREA. THUNDERSTORM ACTIVITY WILL DIMINISH BY LATE EVENING.
PREV DISCUSSION... /ISSUED 412 PM CDT SAT JUL 28 2012/
SHORT TERM...THROUGH LATE SUNDAY AFTERNOON. THE MOST IMPORTANT
ISSUE OVER THE NEXT 24 HOURS IS MONITORING FOR STRONG TO SEVERE
CONVECTION MAINLY THROUGH MIDNIGHT TONIGHT...WITH SECONDARY
CONCERNS CONSISTING OF NEAR HEAT ADVISORY CONDITIONS MAINLY IN
NORTH CENTRAL KS ZONES SUNDAY AFTERNOON...AND ALSO VERY-NEAR
CRITICAL FIRE WEATHER CONDITIONS THROUGH EARLY THIS EVENING IN
SOUTHWEST ZONES.
19Z OBJECTIVE SURFACE ANALYSIS INDICATES WHAT ESSENTIALLY AMOUNTS
TO A TRIPLE POINT ACROSS SOUTHWEST PORTIONS OF THE CWA...AS A
WELL-DEFINED NORTHWEST-SOUTHEAST ORIENTED WARM FRONT CONTINUES
SURGING NORTHEAST INTO THE CWA...WHILE A WEAK SURFACE TROUGH
EXTENDS FROM THE FURNAS COUNTY AREA NORTHWARD INTO NORTH CENTRAL
NEB. AS EXPECTED...TEMPERATURES HAVE SOARED IN THE SOUTHWESTERLY
FLOW IN THE WAKE OF THE WARM FRONT...WITH A SEASONABLY IMPRESSIVE
MID AFTERNOON TEMPERATURE GRADIENT RANGING FROM THE UPPER 80S-LOW
90S IN NORTH/NORTHEAST ZONES...TO 102-108 IN SEVERAL SOUTHWEST
COUNTIES. WIND DIRECTION IS ALSO SHOWING A RATHER SHARP VARIANCE
ACROSS THE WARM FRONT...TRANSITIONING FROM SOUTHEASTERLY TO
SOUTHWESTERLY AS THE WARM FRONT PASSES...ALONG WITH A NOTICEABLE
DECREASE IN DEWPOINTS. VISIBLE SATELLITE IMAGERY IS SHOWING QUITE
A BIT OF MID LEVEL CLOUD COVER INCREASING OVER THE CWA FROM THE
NORTHWEST...WHILE ALONG THE ADVANCING WARM FRONT AND TRIPLE POINT
AREA...THUS FAR WEAK ISOLATED/SCATTERED SHOWERS/STORMS ARE
DEVELOPING ON THE LEADING EDGE OF A SCATTERED CUMULUS
FIELD...WITH THE BOUNDARY LAYER CUMULUS AREA CLOSELY TIED TO THE
EDGE OF A NORTHEASTWARD ADVANCING PLUME OF STEEP LOW LEVEL LAPSE
RATES. WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA REVEALS THE
CENTER OF THE PRIMARY MID-UPPER RIDGE OVER THE SOUTHERN
PLAINS...WITH THE CWA AND CENTRAL/NORTHERN PLAINS REGION
UNDERNEATH THE SEASONABLY RESPECTABLE WEST-NORTHWEST FLOW ALOFT
ALONG THE PERIPHERY OF THE RIDGE...WITH THE ONLY DISCERNIBLE
SHORTWAVE ON WATER VAPOR IMAGERY ACROSS SD.
STARTING OFF WITH FIRE WEATHER THE NEXT FEW HOURS...IN HINDSIGHT
PROBABLY COULD HAVE/SHOULD HAVE ISSUED A FIRE WEATHER HEADLINE FOR A
HANDFUL OF SOUTHWESTERN COUNTIES AS RELATIVE HUMIDITY VALUES HAVE
CRASHED TO NEAR OR JUST BELOW 20 PERCENT BEHIND THE SURGING WARM
FRONT AND WIND GUSTS HAVE FAIRLY CONSISTENTLY REACHED/TOPPED 25
MPH. HOWEVER...BEING PAST MID AFTERNOON ALREADY...WILL FOREGO
WARNING ISSUANCE AND KEEP ELEVATED FIRE DANGER MENTION IN THE HWO
AND EXTREME FIRE DANGER CATEGORY IN THE GRASSLAND FIRE DANGER
PRODUCT.
TURNING TO THUNDERSTORM CHANCES/SEVERITY...PLENTY OF QUESTIONS
STILL REMAIN REGARDING COVERAGE AND SEVERITY. FOR ONE THING...THE
FAIRLY EXPANSIVE BAND OF MID CLOUDS OVERTAKING MUCH OF THE CWA IS
LIKELY NOT DOING ANY FAVORS FOR HELPING THE CURRENTLY WEAK
CONVECTION MAINLY IN SOUTHWEST ZONES OVERCOME AT LEAST A WEAK
CAPPING INVERSION...WHILE AT THE SAME TIME...HOURLY MESOSCALE
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR SEVERE WITH
1000-2000 J/KG MLCAPE...AND AT LEAST 30KT OF 0-6KM DEEP LAYER
SHEAR...WHICH IS ENOUGH TO GET AT LEAST BRIEF SUPERCELL STRUCTURES
GOING. LEANING ON HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4K
WRF-NMM...ANTICIPATE STORMS TO GRADUALLY INCREASE IN COVERAGE AND
INTENSITY AS THE LATE AFTERNOON/EVENING WEARS ON...ESPECIALLY
ACROSS THE SOUTHERN 2/3 OF THE CWA. HOWEVER...GIVEN CONTINUED
UNCERTAINTY IN ULTIMATE COVERAGE AND DESIRE TO NOT GET RAIN HOPES UP
TOO MUCH IN THIS DROUGHT PATTERN...HAVE OPTED TO LIMIT POPS TO NO
MORE THAN 30 PERCENT/SCATTERED COVERAGE FOR NOW THROUGH 06Z. ANY
STRONG/SEVERE STORMS THAT GET GOING SHOULD PRIMARILY POSE A WIND
THREAT...GIVEN STEEP LOW LEVEL LAPSE RATES AND CONSIDERABLE
SURFACE TEMP-DEWPOINT DEPRESSIONS AND RESULTANT HIGH CLOUD BASES.
HOWEVER...HAIL TO AROUND QUARTER SIZE CANNOT BE RULED OUT
COMPLETELY. ALTHOUGH SPC HAS OFFICIALLY LEFT THE SOUTHWEST 1/3 OR
SO OF THE CWA OUT OF A SLIGHT RISK...FOR LOCAL PRODUCT PURPOSES
FEEL THAT INCLUDING ALL 30 COUNTIES IN A SLIGHT RISK SCENARIO FOR
WIND/HAIL IS THE WAY TO GO. WOULD EXPECT INDIVIDUAL/MULTICELL
UPDRAFTS TO POSSIBLY CONGEAL INTO A BROKEN SOUTH-SOUTHEAST MOVING
LINE AT SOME POINT THIS EVENING ACROSS THE SOUTHERN CWA...POSSIBLY
ENHANCING A LOCALIZED WIND THREAT. AFTER 06Z...INTRODUCED A 20 POP
ACROSS A FEW FAR SOUTHEASTERN COUNTIES TO ACCOUNT FOR THE
POSSIBILITY OF LINGERING OVERNIGHT STORMS ALONG A VEERING LOW
LEVEL JET AXIS...BUT BY THIS TIME ANTICIPATE ANY SEVERE THREAT TO
BE ON THE WANE. TEMP WISE TONIGHT...NUDGED DOWN LOWS A FEW DEGREES
MOST AREAS PER GUIDANCE CONSENSUS...RANGING FROM LOW 60S FAR
NORTHWEST TO AROUND 70 FAR SOUTHEAST.
GETTING INTO THE DAYTIME HOURS TOMORROW...AND STARTING WITH
TEMPERATURES...AM WONDERING JUST HOW WARM IT IS GOING TO GET WITH
NORTHEAST/EASTERLY BREEZES FLOWING INTO THE CWA IN THE FORM A WEAK
BACK DOOR COLD FRONT FLOWING OUT OF A SURFACE HIGH TO THE
NORTHEAST. HOWEVER...WITH 850MB TEMPERATURES STAYING QUITE
TOASTY...IT WON/T TAKE MUCH MIXING TO GET THINGS CLIMBING FAST. AS
A RESULT...ONLY NUDGED DOWN HIGHS AN AVERAGE OF 1-2 DEGREES MOST
AREAS...STILL CALLING FOR MID-UPPER 90S IN MOST NEB ZONES...AND
100-105 IN KS ZONES AND FURNAS COUNTY AREA. ALTHOUGH CONFIDENCE IS
LOW REGARDING DEWPOINT TRENDS...WITH THE NAM SOMEWHAT INEXPLICABLY
CRASHING DEWPOINTS ALL THE WAY INTO THE UPPER 30S IN NORTHERN
AREAS ALTHOUGH THIS SOLUTION WAS NOT FOLLOWED...CURRENT GRIDS
YIELD HEAT INDEX VALUES IN THE 103-105 RANGE ACROSS PARTS OF KS
ZONES...WHICH COULD NECESSITATE HEAT ADVISORY ISSUANCE.
HOWEVER...WITH SOME UNCERTAINTY REMAINING REGARDING THE STRENGTH
OF THE BACK DOOR COLD FRONT ALONG WITH DEWPOINTS...WILL DEFER TO
OVERNIGHT SHIFT FOR POSSIBLE ADVISORY ISSUANCE...AND CONTINUE TO
MENTION HEAT IN THE HAZARDOUS WEATHER OUTLOOK. AS FOR STORM
CHANCES...LEFT THE MORNING HOURS FREE OF RAIN MENTION...ALTHOUGH
SOME ACTIVITY COULD BE FESTERING RATHER CLOSE TO THE FAR SOUTHERN
EDGE OF THE CWA. FOR THE AFTERNOON HOURS...TRIMMED BACK THE AREA
OF SLIGHT POPS TO ONLY AREAS MAINLY SOUTH OF A CAMBRIDGE-SMITH
CENTER LINE...WHERE THE PRIMARY SURFACE FRONT WILL STALL OUT AND
FOCUS A POSSIBLE INSTABILITY AXIS. AT THIS TIME...NOT ANTICIPATING
A SEVERE THREAT DURING THE DAYTIME PERIOD...BUT IN THIS TRICKY
PATTERN WITH ONE SUBTLE SHORTWAVE AFTER ANOTHER MOVING ACROSS THE
TOP OF THE UPPER RIDGE AXIS...THINGS ARE SUBJECT TO CHANGE ON
SOMEWHAT SHORT NOTICE.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. BIGGEST CHALLENGE WILL
BE DETERMINING CHANCES AND TIMING OF ANY PRECIPITATION. ENSEMBLE
MEANS FROM THE ECMWF SEEM THE BEST BET FOR CONSISTENCY. WE BEGIN
THE LONG TERM WITH THE SOUTH CENTRAL PLAINS ANTICYCLONE HEAVILY
INFLUENCING OUR WEATHER...BUT WITH NUMEROUS SHALLOW PERTURBATIONS
ALONG THE PERIPHERY TO THROW UNCERTAINTY INTO THE FORECAST.
UNCERTAINTY ALSO EXISTS FOR WHAT KIND OF SURFACE FEATURES WE MIGHT
HAVE...BUT WE COULD HAVE A FRONT DRAPED ACROSS THE CWA SUNDAY
NIGHT...AS SUGGESTED BY SOME MODELS...THAT COULD BE A FOCUS FOR
ELEVATED CONVECTION...MAINLY ALONG AND JUST NORTH OF THE BOUNDARY.
AN EAST-WEST ORIENTED THETA-E RIDGE IS ADVERTISED TO DRAPE ACROSS
SOUTH CENTRAL NEBRASKA FOR SUNDAY NIGHT...WHICH SUGGESTS THAT
CHANCES OF PRECIPITATION IN THE FORECAST ARE WARRANTED. THERE
COULD BE BOUNDARIES DRAPED ACROSS PARTS OF THE CWA FOR THE BULK OF
THE LONG TERM AS WELL...AS THE FORECAST GETS A LITTLE MUDDLED WITH
POTENTIALLY COMPLICATED SURFACES FEATURES.
THE ANTICYCLONE/RIDGE WILL RETROGRADE SOMEWHAT BY MONDAY...WITH
PERTURBATIONS CONTINUING TO PLAY HAVOC ON ANY CERTAINTY IN THE
FORECAST. THE UPPER LEVEL HIGH WILL CONTINUE TO BE A PROMINENT
FEATURE FOR THE REMAINDER OF THE LONG TERM...HOWEVER. MODELS ARE
KEEPING POTENTIALLY SIGNIFICANT AMOUNTS OF MID-HIGH LEVEL CLOUDINESS
AROUND ON TUESDAY...AND I WILL KNOCK DOWN TEMPERATURES A BIT FROM
THE PREVIOUS FORECAST FOR THIS REASON. WITH THE UPPER LEVEL HIGH IN
PLACE FOR THE REST OF THE WEEK...THIS MEANS MORE ABOVE NORMAL
TEMPERATURES...EVEN WITH ADDITIONAL MID TO UPPER LEVEL CLOUDINESS.
SINCE THE HIGH RETROGRADES A BIT...THIS SHOULD ALLOW A BIT MORE
CHANCES OF PRECIPITATION MORE OFTEN WITH FREQUENT PERTURBATIONS
POSSIBLE. THE ECMWF INDICATES A BIT MORE SIZABLE OF A SHORTWAVE
TROUGH CUTTING THROUGH THE NORTHERN/CENTRAL PLAINS FOR
SATURDAY...WHICH WILL HELP FLATTEN THE RIDGE SOMEWHAT...AND PERHAPS
GIVE A BETTER SHOT AT PRECIPITATION THAN THE LOW CONFIDENCE/LOW
CHANCE PRECIPITATION PATTERN FOR MUCH OF THE LONG TERM. JUDGING BY
THE POTENTIAL STRENGTH OF THE WAVE...THIS COULD BE THE MOST
POTENTIAL FOR SEVERE WEATHER IN THE LONG TERM AS WELL...NOT TO SAY
THERE COULD NOT BE A STRONG STORM WITH ANY CONVECTION THAT MAY FIRE
ALONG THE WAY DURING THE EXTENDED. ALTHOUGH...THE 12Z ECMWF HAS JUST
BACKED OFF OF THE AMPLITUDE OF THE WAVE ON SATURDAY...THIS WAVE
STILL BEARS WATCHING FOR POTENTIAL PRECIPITATION AND PERHAPS STRONG
TO SEVERE WEATHER.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY TOWARD THE SOUTHEAST THROUGH THE AREA
TODAY... BEFORE STALLING OUT OVER EASTERN VIRGINIA AND CENTRAL NORTH
CAROLINA THROUGH MONDAY. THE FRONT WILL WEAKEN AND DISSIPATE BY
MONDAY NIGHT. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE
SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY... RESULTING IN
UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 AM SUNDAY...
OVERALL PICTURE: THE LATEST SURFACE ANALYSIS SHOWS THE SURFACE FRONT
HAVING DRIFTED SOUTHEASTWARD IN THE LAST SEVERAL HOURS... TO A
POSITION ACROSS CENTRAL NC TO THE NC FOOTHILLS TO EXTREME NRN GA/AL.
IN THE MID LEVELS... WE REMAIN IN A PATTERN FEATURING A STRONG
ANTICYCLONE CENTERED OVER OK AND THE TX PANHANDLE AND TROUGHING IN
THE EAST. A WEAK PERTURBATION IS NOW PASSING THROUGH THE BASE OF THE
TROUGH THROUGH VA AND NRN NC... WITH A SECOND WEAKENING WAVE
DROPPING THROUGH KY AND A THIRD STRONGER WAVE OVER MN... ALSO
DROPPING TOWARD THE SE. WATER VAPOR IMAGERY AND BLENDED TOTAL PRECIP
WATER IMAGERY BOTH INDICATE DRY AIR HAVING MOVED INTO THE NRN/WRN
PORTIONS OF CENTRAL NC AND PW VALUES VERY CLOSE TO SEASONAL NORMALS
ACROSS THE REGION.
FOR TODAY/TONIGHT: PATCHY SHOWERS PERSIST OVER THE FAR SOUTHEAST
FRINGES OF THE FORECAST AREA... BUT OTHERWISE THE STRONG TO SEVERE
STORMS FROM LAST EVENING HAVE DIMINISHED... LEAVING JUST A COUPLE
HUNDRED J/KG OF SURFACE CAPE OVER THE EXTREME SOUTHERN SECTIONS AND
WEAK LAPSE RATES AREAWIDE. WITH WANING MOISTURE AND SUPPORT FOR
LIFT... WE SHOULD SEE A CONTINUE DISSOLUTION OF WHAT LITTLE PRECIP
IS OUT THERE BY DAWN. THE DEPARTING WEAK WAVE... THE INCOMING DRIER
AIR THROUGH THE COLUMN AS EXHIBITED ON GFS FORECAST SOUNDINGS AS
WELL AS UPSTREAM OBSERVED SOUNDINGS... AND THE EXITING UPPER
DIVERGENCE AS THE RIGHT ENTRANCE REGION OF THE JET ORIENTED ALONG
THE NORTHEAST COAST MOVES OFFSHORE SHOULD ALL WORK IN CONCERT TO
INHIBIT CONVECTION THROUGH THIS MORNING. WE SHOULD SEE ANOTHER
INLAND-TRACKING SEA BREEZE DEVELOP BY MIDDAY... PROVIDED THAT THE
CURRENT EXPANSE OF MID AND HIGH CLOUDS OVER THE COASTAL PLAIN AND
COASTAL AREA THINS OUT SUFFICIENTLY. IF IT DOES... WE SHOULD SEE
LIFT FORCED ALONG THE SEA BREEZE IN CONJUNCTION WITH DAYTIME HEATING
AND MOIST NEAR-SURFACE AIR TO GENERATE SHOWERS AND STORMS OVER THE
SOUTHEASTERN FORECAST AREA BY EARLY AFTERNOON. THE NEAR TO SLIGHTLY
BELOW NORMAL PW VALUES OVER THE NRN/WRN FORECAST AREA SHOULD LIMIT
INLAND PENETRATION OF ANY SUCH SEA BREEZE CONVECTION... AND
LINGERING SUBSIDENCE IN THE WAKE OF THE WEAK WAVE MAY FURTHER HINDER
STORM DEVELOPMENT. AS SUCH... HAVE CONFINED SCATTERED STORMS TO JUST
THE SOUTHEASTERN FORECAST AREA WITH NO BETTER THAN ISOLATED
SPREADING INTO THE ERN PIEDMONT AND WRN SANDHILLS LATER IN THE
AFTERNOON AS SHOWN BY THE SPC CONVECTION-ALLOWING 4-KM WRF MODEL...
BEFORE LOSS OF HEATING LEADS TO GRADUAL DISSIPATION OF CONVECTION
THROUGH THE MID TO LATE EVENING. INSTABILITY SHOULD BE MARGINAL AT
BEST WITH MLCAPE UNDER 500 J/KG OVER ALL BUT THE FAR SRN/ERN
COUNTIES... AND POOR DEEP-LAYER SHEAR WILL CUT BACK ON STORM
DEVELOPMENT... STRENGTH... AND ORGANIZATION AS WELL. THICKNESSES
THIS MORNING ARE EXPECTED TO BE SIMILAR TO YESTERDAY`S BUT NOT
RISING QUITE AS MUCH DURING THE DAY DUE TO SLIGHT COOLING AT 850 MB.
FACTORING THIS IN... EXPECT HIGHS OF 91-96... JUST A SHADE UNDER
SATURDAY`S HIGHS. WILL FOLLOW PERSISTENCE WITH LOWS... 68-74.
FORECAST SOUNDINGS AND STATISTICAL GUIDANCE ALONG WITH THE OVERALL
PATTERN ALL FAVOR FOG DEVELOPMENT LATE TONIGHT. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...
MONDAY....
WITH THE UPPER RIDGE PARKED OVER THE CENTRAL US...THE UPPER TROUGH
WILL PERSIST OVER THE EASTERN US THIS WEEK...WITH MODELS SHOWING A
PAIR OF DISTURBANCES ON THE NORTHWEST FLOW ALOFT THAT SHOULD AUGMENT
CONVECTIVE POTENTIAL MONDAY AND TUESDAY. THE STALLED OUT FRONTAL
ZONE IN THE VICINITY OF THE EASTERN PIEDMONT AND COASTAL PLAIN
SHOULD BE THE PRIMARY FOCUS FOR CONVECTION ON MONDAY...THOUGH THE
NAM/ECMWF SUGGEST THE BOUNDARY MAY SHIFT BACK WESTWARD AS
SOUTHEASTERLY LOW LEVEL FLOW DEVELOPS IN RESPONSE TO A WEAK 850MB
WAVE DRIFTING NORTHEAST OUT OF SC. DESPITE BACKED SURFACE
WINDS/SHORT CURVED HODOGRAPHS AND MLCAPE VALUES PROJECTED TO REACH
1500 J/KG...THE OVERALL WEAK TROPOSPHERIC FLOW FLOW SHOULD LIMIT THE
SEVERITY OF STORMS MONDAY AFTERNOON. PW VALUES SURGING TO AROUND 2
INCHES SUGGEST THE MAIN THREAT FORM STORMS WOULD BE DAMAGING WINDS
VA PRECIP LOADED AND SOME ISOLATED MINOR FLOODING POTENTIAL.
LOW LEVEL THICKNESSES OF AROUND 1415M ARE FORECAST MONDAY
AFTERNOON... WHICH IS ONLY ABOUT 5M ABOVE NORMAL FOR EARLY AUGUST.
HIGHS 89-92.
MONDAY NIGHT...
A FEW SHOWERS/STORMS COULD PERSIST INTO THE OVERNIGHT HOURS AS
OUTFLOW BOUNDARY LINGER IN THE MOIST AIRMASS...BUT THE COVERAGE OF
CONVECTION SHOULD DECREASE SIGNIFICANTLY AFTER SUNSET. LOWS IN THE
LOWER 70S.
TUESDAY/TUESDAY NIGHT...
CONDITIONS ARE EXPECTED TO AGAIN BE RIPE FOR SCATTERED TO NUMEROUS
STORMS TUESDAY AS MODELS AGREE ON ANOTHER...MORE PRONOUNCED
DISTURBANCE ALOFT DIVING INTO THE BASE OF THE UPPER TROUGH DURING
PEAK HEATING. WITH THE LEE TROUGH EXPECTED TO AGAIN BE THE MAIN LOW
LEVEL FOCUS FOR DEVELOPMENT...STRONG HEATING (HIGHS IN THE LOWER
90S) AND DESTABILIZATION...ALONG WITH SLIGHTLY BETTER DEEP LAYER
SHEAR SUPPORT A BETTER SEVERE THREAT. THERE IS THE POTENTIAL FOR
SHOWERS AND STORMS TO CONTINUE INTO THE OVERNIGHT PERIOD TUESDAY
NIGHT WITH MODELS SHOWING AN 850MB TROUGH PUSHING EAST THROUGH THE
AREA AFTER 00Z AS THE UPPER TROUGH AXIS SHIFTS EAST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN RELATIVELY UNCHANGED
THROUGH THE REMAINDER OF THE WEEK...WITH GENERALLY RIDGING OVER THE
CENTRAL TO WESTERN US AND TROUGHING OVER THE EAST. WHILE NORTHWEST
FLOW WILL CONTINUE ALOFT AND WILL SUPPORT DIURNAL CONVECTION ALONG
THE HIGHER TERRAIN/LEE TROUGH/SEA-BREEZE...IT APPEARS CONVECTION
WILL BE MORE WIDELY SCATTERED. MEDIUM RANGE GUIDANCE
PROJECTS LOW LEVEL THICKNESSES HOLDING NEAR 1425M EACH DAY...WHICH
SHOULD LEAD TO HIGHS IN THE LOWER 90S WITH LOWS CONSISTENTLY IN THE
LOWER 70S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO LAST FOR A FEW MORE HOURS OVERNIGHT
BEFORE THEY GIVE WAY TO MVFR VSBYS AS PATCHY LIGHT FOG DEVELOPS NEAR
RDU/RWI/FAY... LOCATIONS THAT RECEIVED A SOAKING RAIN FROM
THUNDERSTORMS LAST EVENING. BUT THE CONSIDERABLE MID AND HIGH CLOUDS
AT THESE SITES SHOULD INHIBIT RADIATIONAL COOLING AND BOTH DELAY
DEVELOPMENT AND LIMIT DENSITY OF FOG. RDU SHOULD SEE THE BEST CHANCE
OF SEVERAL HOURS OF MVFR FOG -- POSSIBLY DROPPING TO IFR -- GIVEN
THE COMBINATION OF PLENTY OF RAIN... LIGHT WINDS... AND AN EARLY
CLEARING OF CONVECTIVE DEBRIS MID AND HIGH CLOUDS. SURE ENOUGH...
THE LATEST HRRR EXPERIMENTAL AVIATION MODEL OUTPUT PLACES A PATCH OF
LOW VSBY NEAR RDU TOWARD MORNING. AT GSO/INT... ANY FOG IS EXPECTED
TO BE MORE THIN AND SHORT-LIVED AS THESE TWO SITES RECEIVED ONLY
BRIEF LIGHT RAIN NEAR THE TERMINALS... AND DRIER AIR IS SLOWLY
WORKING INTO THE TRIAD AREA FROM THE NORTHWEST. ANY FOG WILL LIFT
AND MIX OUT WITH HEATING BY 13Z-14Z. VFR CIGS ARE EXPECTED TO FORM
AT ALL SITES AFTER 16Z... WITH MORE EXPANSIVE CLOUD COVER AT
RDU/RWI/FAY. A FEW STORMS ARE EXPECTED NEAR FAY AFTER 17Z... EAST OF
A WEAKENING FRONT STALLED ACROSS THE AREA... WITH A LESSER CHANCE AT
RDU/RWI AND A VERY LOW CHANCE AT GSO/INT. ANY SHOWERS/STORMS IN THE
SOUTHEAST PORTION OF CENTRAL NC WILL DISSIPATE BY 03Z.
LOOKING BEYOND 06Z MONDAY (LATE TONIGHT)... IFR FOG IS POSSIBLE VERY
LATE TONIGHT INTO MONDAY MORNING AT ALL SITES AS HIGH HUMIDITY AND
LIGHT WINDS NEAR THE WEAKENING STALLED FRONT FACILITATE FOG
DEVELOPMENT. SCATTERED STORMS ARE ANTICIPATED MAINLY AT RDU/RWI/FAY
MONDAY AFTERNOON INTO EVENING. MORE MVFR/IFR FOG COULD OCCUR EARLY
TUESDAY MORNING. GREATER COVERAGE OF STORMS IS EXPECTED TUESDAY
AFTERNOON INTO THE NIGHT WITH LOCALLY GUSTY WINDS AND LOW CIGS/VSBY
IN/NEAR STORMS. THE OVERALL PATTERN WEAKENS AND BECOMES MORE
ILL-DEFINED MID-LATE WEEK. WHILE TYPICAL SCATTERED LATE DAY STORMS
ARE POSSIBLE AT ALL SITES WEDNESDAY/THURSDAY... DETAILS CANNOT BE
DETERMINED AT THIS TIME... BUT THE RISK OF MORNING FOG SHOULD BE
LOWER IN THIS TIME FRAME. -GIH
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 AM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY TOWARD THE SOUTHEAST THROUGH THE AREA
TODAY... BEFORE STALLING OUT OVER EASTERN VIRGINIA AND CENTRAL NORTH
CAROLINA THROUGH MONDAY. THE FRONT WILL WEAKEN AND DISSIPATE BY
MONDAY NIGHT. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE
SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY... RESULTING IN
UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 AM SUNDAY...
OVERALL PICTURE: THE LATEST SURFACE ANALYSIS SHOWS THE SURFACE FRONT
HAVING DRIFTED SOUTHEASTWARD IN THE LAST SEVERAL HOURS... TO A
POSITION ACROSS CENTRAL NC TO THE NC FOOTHILLS TO EXTREME NRN GA/AL.
IN THE MID LEVELS... WE REMAIN IN A PATTERN FEATURING A STRONG
ANTICYCLONE CENTERED OVER OK AND THE TX PANHANDLE AND TROUGHING IN
THE EAST. A WEAK PERTERBATION IS NOW PASSING THROUGH THE BASE OF THE
TROUGH THROUGH VA AND NRN NC... WITH A SECOND WEAKENING WAVE
DROPPING THROUGH KY AND A THIRD STRONGER WAVE OVER MN... ALSO
DROPPING TOWARD THE SE. WATER VAPOR IMAGERY AND BLENDED TOTAL PRECIP
WATER IMAGERY BOTH INDICATE DRY AIR HAVING MOVED INTO THE NRN/WRN
PORTIONS OF CENTRAL NC AND PW VALUES VERY CLOSE TO SEASONAL NORMALS
ACROSS THE REGION.
FOR TODAY/TONIGHT: PATCHY SHOWERS PERSIST OVER THE FAR SOUTHEAST
FRINGES OF THE FORECAST AREA... BUT OTHERWISE THE STRONG TO SEVERE
STORMS FROM LAST EVENING HAVE DIMINISHED... LEAVING JUST A COUPLE
HUNDRED J/KG OF SURFACE CAPE OVER THE EXTREME SOUTHERN SECTIONS AND
WEAK LAPSE RATES AREAWIDE. WITH WANING MOISTURE AND SUPPORT FOR
LIFT... WE SHOULD SEE A CONTINUE DISSOLUTION OF WHAT LITTLE PRECIP
IS OUT THERE BY DAWN. THE DEPARTING WEAK WAVE... THE INCOMING DRIER
AIR THROUGH THE COLUMN AS EXHIBITED ON GFS FORECAST SOUNDINGS AS
WELL AS UPSTREAM OBSERVED SOUNDINGS... AND THE EXITING UPPER
DIVERGENCE AS THE RIGHT ENTRANCE REGION OF THE JET ORIENTED ALONG
THE NORTHEAST COAST MOVES OFFSHORE SHOULD ALL WORK IN CONCERT TO
INHIBIT CONVECTION THROUGH THIS MORNING. WE SHOULD SEE ANOTHER
INLAND-TRACKING SEA BREEZE DEVELOP BY MIDDAY... PROVIDED THAT THE
CURRENT EXPANSE OF MID AND HIGH CLOUDS OVER THE COASTAL PLAIN AND
COASTAL AREA THINS OUT SUFFICIENTLY. IF IT DOES... WE SHOULD SEE
LIFT FORCED ALONG THE SEA BREEZE IN CONJUNCTION WITH DAYTIME HEATING
AND MOIST NEAR-SURFACE AIR TO GENERATE SHOWERS AND STORMS OVER THE
SOUTHEASTERN FORECAST AREA BY EARLY AFTERNOON. THE NEAR TO SLIGHTLY
BELOW NORMAL PW VALUES OVER THE NRN/WRN FORECAST AREA SHOULD LIMIT
INLAND PENETRATION OF ANY SUCH SEA BREEZE CONVECTION... AND
LINGERING SUBSIDENCE IN THE WAKE OF THE WEAK WAVE MAY FURTHER HINDER
STORM DEVELOPMENT. AS SUCH... HAVE CONFINED SCATTERED STORMS TO JUST
THE SOUTHEASTERN FORECAST AREA WITH NO BETTER THAN ISOLATED
SPREADING INTO THE ERN PIEDMONT AND WRN SANDHILLS LATER IN THE
AFTERNOON AS SHOWN BY THE SPC CONVECTION-ALLOWING 4-KM WRF MODEL...
BEFORE LOSS OF HEATING LEADS TO GRADUAL DISSIPATION OF CONVECTION
THROUGH THE MID TO LATE EVENING. INSTABILITY SHOULD BE MARGINAL AT
BEST WITH MLCAPE UNDER 500 J/KG OVER ALL BUT THE FAR SRN/ERN
COUNTIES... AND POOR DEEP-LAYER SHEAR WILL CUT BACK ON STORM
DEVELOPMENT... STRENGTH... AND ORGANIZATION AS WELL. THICKNESSES
THIS MORNING ARE EXPECTED TO BE SIMILAR TO YESTERDAY`S BUT NOT
RISING QUITE AS MUCH DURING THE DAY DUE TO SLIGHT COOLING AT 850 MB.
FACTORING THIS IN... EXPECT HIGHS OF 91-96... JUST A SHADE UNDER
SATURDAY`S HIGHS. WILL FOLLOW PERSISTENCE WITH LOWS... 68-74.
FORECAST SOUNDINGS AND STATISTICAL GUIDANCE ALONG WITH THE OVERALL
PATTERN ALL FAVOR FOG DEVELOPMENT LATE TONIGHT. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN IN THIS PERIOD WILL BE CHARACTERIZED BY
TROUGHING ALOFT OVER THE MID-ATLANTIC/CAROLINAS...ON THE EASTERN
PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL CONUS.
GIVEN TROUGHING ALOFT IN THE PRESENCE OF A SEASONABLY MOIST/UNSTABLE
AIRMASS...EXPECT ABOVE-NORMAL CHANCES FOR SHOWERS AND STORMS...
PRIMARILY DURING THE AFTERNOON/EVENING HOURS. SMALL AMPLITUDE
DISTURBANCES EMBEDDED WITHIN CYCLONIC FLOW ALOFT MON/TUE AND
INCREASINGLY NW FLOW ALOFT TUE NIGHT WILL ALLOW ISOLD/SCT CONVECTION
TO REMAIN POSSIBLE DURING THE OVERNIGHT HOURS...THOUGH THIS WILL
HIGHLY DEPEND ON THE EVOLUTION OF THE AFOREMENTIONED DISTURBANCES
AND THE EXTENT TO WHICH CONVECTIVE OVERTURNING OCCURS DURING THE
LATE AFTERNOON AND EVENING HOURS. WILL INDICATE 40-60% CHANCES FOR
SHOWERS/STORMS ON MONDAY WHEN MORE PRONOUNCED CYCLONIC FLOW ALOFT
WILL BE PRESENT...40-50% ON TUE...WITH CHANCES DECREASING TO 20%
AFTER MIDNIGHT. HIGHS ON BOTH MON/TUE SHOULD BE NEAR NORMAL IN THE
UPPER 80S/LOWER 90S) BASED ON 1000-850 MB THICKNESSES IN VICINITY OF
1415 METERS. LOWS ALSO SHOULD BE NEAR NORMAL...69-72F. THE PRIMARY
UNCERTAINTY WITH TEMPERATURES WILL BE THE TIMING/LOCATION OF
CONVECTION...AND CLOUD COVER ASSOCIATED WITH CONVECTION OR THE
REMNANTS THEREOF. A THREAT FOR ISOLD SEVERE THUNDERSTORMS CAPABLE OF
PRODUCING DAMAGING WINDS WILL REMAIN PRESENT DURING THE MID/LATE
AFTERNOON AND EVENING HOURS ON BOTH MONDAY AND TUESDAY. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN OVER THE CAROLINAS AND MID-ATLANTIC WED-SAT
WILL BE CHARACTERIZED INITIALLY (WED/THU) BY NW FLOW ALOFT...
TRANSITIONING (FRI/SAT) TO BROAD CYCLONIC FLOW ALOFT ON THE EASTERN
PERIPHERY OF A WEAKENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS.
PRECIPITATION CHANCES...I.E. THE TIMING/LOCATION/COVERAGE OF
CONVECTION...WILL BE HIGHLY DEPENDENT ON THE EVOLUTION OF SMALL
AMPLITUDE DISTURBANCES PROGRESSING SOUTHEAST FROM THE UPPER
MIDWEST/CENTRAL MS RIVER VALLEY INTO THE MID-ATLANTIC AND CAROLINAS.
DUE TO NW/CYCLONIC FLOW ALOFT IN THE PRESENCE OF A SEASONABLY
MOIST/UNSTABLE AIRMASS...WILL INDICATE CHANCES FOR SHOWERS/STORMS
SLIGHTLY ABOVE CLIMATOLOGY IN THE 30-40% RANGE...WITH A SLIGHT
CHANCE (20%) PERSISTING DURING THE OVERNIGHT HOURS. TEMPERATURES
WILL PRIMARILY DEPEND ON THE EVOLUTION OF CONVECTION AND ASSOCIATED
CLOUD COVER...WITH 1000-850 MB THICKNESSES SUGGESTING HIGHS AND LOWS
NEAR NORMAL...IN THE UPPER 80S TO LOWER 90S AND UPPER 60S TO LOWER
70S EACH DAY. -VINCENT
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO LAST FOR A FEW MORE HOURS OVERNIGHT
BEFORE THEY GIVE WAY TO MVFR VSBYS AS PATCHY LIGHT FOG DEVELOPS NEAR
RDU/RWI/FAY... LOCATIONS THAT RECEIVED A SOAKING RAIN FROM
THUNDERSTORMS LAST EVENING. BUT THE CONSIDERABLE MID AND HIGH CLOUDS
AT THESE SITES SHOULD INHIBIT RADIATIONAL COOLING AND BOTH DELAY
DEVELOPMENT AND LIMIT DENSITY OF FOG. RDU SHOULD SEE THE BEST CHANCE
OF SEVERAL HOURS OF MVFR FOG -- POSSIBLY DROPPING TO IFR -- GIVEN
THE COMBINATION OF PLENTY OF RAIN... LIGHT WINDS... AND AN EARLY
CLEARING OF CONVECTIVE DEBRIS MID AND HIGH CLOUDS. SURE ENOUGH...
THE LATEST HRRR EXPERIMENTAL AVIATION MODEL OUTPUT PLACES A PATCH OF
LOW VSBY NEAR RDU TOWARD MORNING. AT GSO/INT... ANY FOG IS EXPECTED
TO BE MORE THIN AND SHORT-LIVED AS THESE TWO SITES RECEIVED ONLY
BRIEF LIGHT RAIN NEAR THE TERMINALS... AND DRIER AIR IS SLOWLY
WORKING INTO THE TRIAD AREA FROM THE NORTHWEST. ANY FOG WILL LIFT
AND MIX OUT WITH HEATING BY 13Z-14Z. VFR CIGS ARE EXPECTED TO FORM
AT ALL SITES AFTER 16Z... WITH MORE EXPANSIVE CLOUD COVER AT
RDU/RWI/FAY. A FEW STORMS ARE EXPECTED NEAR FAY AFTER 17Z... EAST OF
A WEAKENING FRONT STALLED ACROSS THE AREA... WITH A LESSER CHANCE AT
RDU/RWI AND A VERY LOW CHANCE AT GSO/INT. ANY SHOWERS/STORMS IN THE
SOUTHEAST PORTION OF CENTRAL NC WILL DISSIPATE BY 03Z.
LOOKING BEYOND 06Z MONDAY (LATE TONIGHT)... IFR FOG IS POSSIBLE VERY
LATE TONIGHT INTO MONDAY MORNING AT ALL SITES AS HIGH HUMIDITY AND
LIGHT WINDS NEAR THE WEAKENING STALLED FRONT FACILITATE FOG
DEVELOPMENT. SCATTERED STORMS ARE ANTICIPATED MAINLY AT RDU/RWI/FAY
MONDAY AFTERNOON INTO EVENING. MORE MVFR/IFR FOG COULD OCCUR EARLY
TUESDAY MORNING. GREATER COVERAGE OF STORMS IS EXPECTED TUESDAY
AFTERNOON INTO THE NIGHT WITH LOCALLY GUSTY WINDS AND LOW CIGS/VSBY
IN/NEAR STORMS. THE OVERALL PATTERN WEAKENS AND BECOMES MORE
ILL-DEFINED MID-LATE WEEK. WHILE TYPICAL SCATTERED LATE DAY STORMS
ARE POSSIBLE AT ALL SITES WEDNESDAY/THURSDAY... DETAILS CANNOT BE
DETERMINED AT THIS TIME... BUT THE RISK OF MORNING FOG SHOULD BE
LOWER IN THIS TIME FRAME. -GIH
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 AM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY TOWARD THE SOUTHEAST THROUGH THE AREA
TODAY... BEFORE STALLING OUT OVER EASTERN VIRGINIA AND CENTRAL NORTH
CAROLINA THROUGH MONDAY. THE FRONT WILL WEAKEN AND DISSIPATE BY
MONDAY NIGHT. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE
SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY... RESULTING IN
UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 958 PM SATURDAY...
SEVERE THUNDERSTORMS ARE WINDING DOWN AS THEY MOVE EAST THROUGH THE
SOUTHERN PINES... RALEIGH... ROCKY MOUNT AND ROANOKE RAPIDS AREA. WE
WILL LET THE WATCH EXPIRE AS THIS ACTIVITY WILL NOT REACH THE
ORIGINAL WATCH AREA DUE TO A STABLE BOUNDARY LAYER IN THE SE.
HOWEVER... ISOLATED SEVERE REPORTS MAY STILL OCCUR FROM SMITHFIELD
TO TARBORO IN THE NEXT HOUR OR TWO BEFORE THE LINE DIES OFF.
OTHERWISE... WILL REDUCE POP TO 20 AFTER MIDNIGHT.
UPDATES OUT SHORTLY. -BADGETT
ON SUNDAY THE BASE OF THE UPPER LEVEL TROUGH WILL PARK SOMEWHERE
IN THE VICINITY OF CENTRAL NORTH CAROLINA. DEPENDING ON POSITIONING
COULD DETERMINE HOW FAR TO THE NORTH AND WEST CONVECTION WILL
PROPAGATE SUNDAY AFTERNOON. REGARDLESS...THE THREAT FOR
CONVECTION...PROBABLY EAST OF HIGHWAY 1...IS CERTAINLY THERE AS
HIGHER DEWPOINTS AND MOIST SOUTHWESTERLY FLOW WILL AID THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS AFTER 18Z. AS OPPOSED TO
SATURDAY...DYNAMIC TROPOPAUSE MAPS SHOW A LACK OF UPSTREAM IMPULSES
TO AID THE DEVELOPMENT AND SUSTAINABILITY OF CONVECTION. THE SEA
BREEZE BOUNDARY WILL LIKELY BE A BIGGER PLAYER SUNDAY AFTERNOON IN
NOT ONLY INITIALIZING CONVECTION BUT HELPING IT TO SPREAD NORTH AND
WEST ACROSS THE EASTERN HALF OF THE CWA. LOW LEVEL LAPSE RATES WILL
BE VERY GOOD BUT THE MID-LEVEL LAPSE RATES WILL BE MORE MARGINAL.
SHEAR WILL BE REDUCED...THEREFORE FACTORS COMING TOGETHER TO SUPPORT
A MORE PULSE LIKE ENVIRONMENT AS OPPOSED TO THE BIT MORE LINEAR
STRUCTURES WE HAVE BEEN SEEING OVER THE PAST WEEK. HIGH TEMPERATURES
WILL TOP OUT IN THE LOW TO MID 90S WITH LOWS IN THE UPPER 60S TO LOW
70S. ANY FOG OR STRATUS THAT WOULD OCCUR SUNDAY NIGHT INTO MONDAY
SHOULD BE CONFINED TO EASTERN SITES...AHEAD OF THE TROUGH AXIS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN IN THIS PERIOD WILL BE CHARACTERIZED BY
TROUGHING ALOFT OVER THE MID-ATLANTIC/CAROLINAS...ON THE EASTERN
PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL CONUS.
GIVEN TROUGHING ALOFT IN THE PRESENCE OF A SEASONABLY MOIST/UNSTABLE
AIRMASS...EXPECT ABOVE-NORMAL CHANCES FOR SHOWERS AND STORMS...
PRIMARILY DURING THE AFTERNOON/EVENING HOURS. SMALL AMPLITUDE
DISTURBANCES EMBEDDED WITHIN CYCLONIC FLOW ALOFT MON/TUE AND
INCREASINGLY NW FLOW ALOFT TUE NIGHT WILL ALLOW ISOLD/SCT CONVECTION
TO REMAIN POSSIBLE DURING THE OVERNIGHT HOURS...THOUGH THIS WILL
HIGHLY DEPEND ON THE EVOLUTION OF THE AFOREMENTIONED DISTURBANCES
AND THE EXTENT TO WHICH CONVECTIVE OVERTURNING OCCURS DURING THE
LATE AFTERNOON AND EVENING HOURS. WILL INDICATE 40-60% CHANCES FOR
SHOWERS/STORMS ON MONDAY WHEN MORE PRONOUNCED CYCLONIC FLOW ALOFT
WILL BE PRESENT...40-50% ON TUE...WITH CHANCES DECREASING TO 20%
AFTER MIDNIGHT. HIGHS ON BOTH MON/TUE SHOULD BE NEAR NORMAL IN THE
UPPER 80S/LOWER 90S) BASED ON 1000-850 MB THICKNESSES IN VICINITY OF
1415 METERS. LOWS ALSO SHOULD BE NEAR NORMAL...69-72F. THE PRIMARY
UNCERTAINTY WITH TEMPERATURES WILL BE THE TIMING/LOCATION OF
CONVECTION...AND CLOUD COVER ASSOCIATED WITH CONVECTION OR THE
REMNANTS THEREOF. A THREAT FOR ISOLD SEVERE THUNDERSTORMS CAPABLE OF
PRODUCING DAMAGING WINDS WILL REMAIN PRESENT DURING THE MID/LATE
AFTERNOON AND EVENING HOURS ON BOTH MONDAY AND TUESDAY. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN OVER THE CAROLINAS AND MID-ATLANTIC WED-SAT
WILL BE CHARACTERIZED INITIALLY (WED/THU) BY NW FLOW ALOFT...
TRANSITIONING (FRI/SAT) TO BROAD CYCLONIC FLOW ALOFT ON THE EASTERN
PERIPHERY OF A WEAKENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS.
PRECIPITATION CHANCES...I.E. THE TIMING/LOCATION/COVERAGE OF
CONVECTION...WILL BE HIGHLY DEPENDENT ON THE EVOLUTION OF SMALL
AMPLITUDE DISTURBANCES PROGRESSING SOUTHEAST FROM THE UPPER
MIDWEST/CENTRAL MS RIVER VALLEY INTO THE MID-ATLANTIC AND CAROLINAS.
DUE TO NW/CYCLONIC FLOW ALOFT IN THE PRESENCE OF A SEASONABLY
MOIST/UNSTABLE AIRMASS...WILL INDICATE CHANCES FOR SHOWERS/STORMS
SLIGHTLY ABOVE CLIMATOLOGY IN THE 30-40% RANGE...WITH A SLIGHT
CHANCE (20%) PERSISTING DURING THE OVERNIGHT HOURS. TEMPERATURES
WILL PRIMARILY DEPEND ON THE EVOLUTION OF CONVECTION AND ASSOCIATED
CLOUD COVER...WITH 1000-850 MB THICKNESSES SUGGESTING HIGHS AND LOWS
NEAR NORMAL...IN THE UPPER 80S TO LOWER 90S AND UPPER 60S TO LOWER
70S EACH DAY. -VINCENT
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO LAST FOR A FEW MORE HOURS OVERNIGHT
BEFORE THEY GIVE WAY TO MVFR VSBYS AS PATCHY LIGHT FOG DEVELOPS NEAR
RDU/RWI/FAY... LOCATIONS THAT RECEIVED A SOAKING RAIN FROM
THUNDERSTORMS LAST EVENING. BUT THE CONSIDERABLE MID AND HIGH CLOUDS
AT THESE SITES SHOULD INHIBIT RADIATIONAL COOLING AND BOTH DELAY
DEVELOPMENT AND LIMIT DENSITY OF FOG. RDU SHOULD SEE THE BEST CHANCE
OF SEVERAL HOURS OF MVFR FOG -- POSSIBLY DROPPING TO IFR -- GIVEN
THE COMBINATION OF PLENTY OF RAIN... LIGHT WINDS... AND AN EARLY
CLEARING OF CONVECTIVE DEBRIS MID AND HIGH CLOUDS. SURE ENOUGH...
THE LATEST HRRR EXPERIMENTAL AVIATION MODEL OUTPUT PLACES A PATCH OF
LOW VSBY NEAR RDU TOWARD MORNING. AT GSO/INT... ANY FOG IS EXPECTED
TO BE MORE THIN AND SHORT-LIVED AS THESE TWO SITES RECEIVED ONLY
BRIEF LIGHT RAIN NEAR THE TERMINALS... AND DRIER AIR IS SLOWLY
WORKING INTO THE TRIAD AREA FROM THE NORTHWEST. ANY FOG WILL LIFT
AND MIX OUT WITH HEATING BY 13Z-14Z. VFR CIGS ARE EXPECTED TO FORM
AT ALL SITES AFTER 16Z... WITH MORE EXPANSIVE CLOUD COVER AT
RDU/RWI/FAY. A FEW STORMS ARE EXPECTED NEAR FAY AFTER 17Z... EAST OF
A WEAKENING FRONT STALLED ACROSS THE AREA... WITH A LESSER CHANCE AT
RDU/RWI AND A VERY LOW CHANCE AT GSO/INT. ANY SHOWERS/STORMS IN THE
SOUTHEAST PORTION OF CENTRAL NC WILL DISSIPATE BY 03Z.
LOOKING BEYOND 06Z MONDAY (LATE TONIGHT)... IFR FOG IS POSSIBLE VERY
LATE TONIGHT INTO MONDAY MORNING AT ALL SITES AS HIGH HUMIDITY AND
LIGHT WINDS NEAR THE WEAKENING STALLED FRONT FACILITATE FOG
DEVELOPMENT. SCATTERED STORMS ARE ANTICIPATED MAINLY AT RDU/RWI/FAY
MONDAY AFTERNOON INTO EVENING. MORE MVFR/IFR FOG COULD OCCUR EARLY
TUESDAY MORNING. GREATER COVERAGE OF STORMS IS EXPECTED TUESDAY
AFTERNOON INTO THE NIGHT WITH LOCALLY GUSTY WINDS AND LOW CIGS/VSBY
IN/NEAR STORMS. THE OVERALL PATTERN WEAKENS AND BECOMES MORE
ILL-DEFINED MID-LATE WEEK. WHILE TYPICAL SCATTERED LATE DAY STORMS
ARE POSSIBLE AT ALL SITES WEDNESDAY/THURSDAY... DETAILS CANNOT BE
DETERMINED AT THIS TIME... BUT THE RISK OF MORNING FOG SHOULD BE
LOWER IN THIS TIME FRAME. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BADGETT/ELLIS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1116 PM CDT SAT JUL 28 2012
.DISCUSSION...LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW A
REPEATING PATTERN OF SHORTWAVES ROTATING FROM THE INTER-MOUNTAIN
WEST INTO NORTH DAKOTA. A SHORTWAVE TROUGH IN SOUTHERN ALBERTA WAS
SUPPRESSING HEIGHTS AS IT CONTINUES TO CIRCULATE/MOVE NORTHEAST
AND ALSO AIDING IN THUNDERSTORM DEVELOPMENT IN SOUTHERN CANADA.
MOISTURE/SHORTWAVE ENERGY ROTATING AROUND A STATIONARY UPPER
LEVEL HIGH CENTERED OVER NORTH TEXAS IN CONJUNCTION WITH THE
AFOREMENTIONED SHORTWAVES HAS BEEN PRODUCING A LINE OF
SHOWERS/THUNDERSTORMS OVER EASTERN MONTANA EARLY TONIGHT WITH
WIND GUSTS REPORTS AS HIGH AS 60 MPH EARLIER. WILL CONTINUE TO
MONITOR AS THIS LINE APPROACHES WESTERN NORTH DAKOTA...BUT THE
OVERALL TREND IS FOR WEAKENING. LOCAL RADAR WAS SHOWING ISOLATED
SHOWERS/THUNDERSTORMS DEVELOPING FROM NEAR MANDAREE TO VELVA AND
MOVING SOUTHEAST. HAVE EXPANDED THE ISOLATED POPS FURTHER SOUTH TO
ACCOUNT FOR THIS ACTIVITY FOR THE REST OF THE NIGHT.
OUR NEXT SHORTWAVE OF INTEREST IS SEEN IN THE SALMON/CHALLIS
MOUNTAINOUS REGION IN CENTRAL IDAHO. THIS IS FORECAST TO MOVE EAST
TONIGHT AND REACH CLOSE TO OUR WESTERN BORDER BY 12Z SUNDAY. THE
LATEST HRRR AND SREF...AND TO SOME EXTENT THE 00Z NAM DO SHOW
ANOTHER AREA OF PRECIPITATION ARRIVING IN OUR WESTERN ZONES BY
AROUND 09Z-10Z. THE HRRR COMPOSITE REFLECTIVITY SUGGESTS THIS
WOULD BE NON-SEVERE AND MAY CONTINUE FROM 10Z TO 14Z SUNDAY.
&&
.AVIATION...LOW PRESSURE IN EASTERN MONTANA WILL MOVE SLOWLY EAST
OVERNIGHT. THIS WILL BE THE FOCUS FOR MORE THUNDERSTORMS OVER WESTERN
AND NORTHERN NORTH DAKOTA...HOWEVER VFR CONDITIONS ARE EXPECTED AT
ALL TAF SITES. THE MAIN HAZARD THROUGH 12Z SUNDAY WILL BE WIDELY
SCATTERED THUNDERSTORMS AT KDIK/KISN/KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
306 AM CDT SUN JUL 29 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
306 AM CDT SUN JUL 29 2012
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE RAIN CHANCES
TODAY AND MONDAY.
A FEW DIFFERENT BANDS OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
ACROSS THE REGION AHEAD OF A 850-500MB TROUGH MOVING THROUGH
MINNESOTA. THIS LOW TO MID LEVEL FORCING WILL PROVIDE THE LIFT TO
KEEP CONVECTION GOING THROUGH THE MORNING HOURS TODAY BEFORE THE
TROUGH MAKES IT INTO EASTERN WISCONSIN THIS AFTERNOON. INSTABILITY
REMAINS RATHER WEAK NEAR THE NORTHERN BAND OF SHOWERS AT LESS
THAN 500 J/KG OF 0-3KM MUCAPE WHILE AN AXIS OF 500-1000 J/KG OF
MUCAPE IS NOSING UP INTO THE CONVECTION IN SOUTHWEST MINNESOTA AND
HAS LED TO SOME MORE LIGHTNING STRIKES THERE. THE BEST CHANCES
FOR ANY PRECIPITATION APPEAR TO BE ALONG AND WEST OF THE
MISSISSIPPI RIVER WITH THE CONVECTION DEVELOPING IN SOUTHWEST
MINNESOTA AHEAD OF THE TROUGH. THIS CONVECTION SHOULD BECOME MORE
WIDESPREAD THROUGH THE MORNING AND TRACK THROUGH SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. MEANWHILE...THE DEFORMATION BAND
ALONG A 800-600MB ZONE HAS SET UP FROM WEST CENTRAL MINNESOTA INTO
CENTRAL WISCONSIN. THE 29.02Z THROUGH 29.04Z HRRR HAS DONE A
FAIRLY GOOD JOB OF PICKING UP ON CURRENT TRENDS AND SHOWS THIS
BAND STICKING TOGETHER THOUGH DIMINISHING IN COVERAGE THROUGH THE
MORNING. BASED ON THIS...HAVE PULLED SOME OF THE HIGHER CHANCES TO
THE NORTHEAST INTO CENTRAL WISCONSIN THOUGH ANY RAINFALL AMOUNTS
SHOULD BE ON THE LOW SIDE. THIS PRECIPITATION LOOKS TO BE ON A
DIMINISHING TREND INTO THE AFTERNOON WITH MUCH OF THE REGION
CLEARING OUT BY THE EVENING AS A SURFACE RIDGE OF HIGH PRESSURE
EXTENDS WEST FROM THE GREAT LAKES INTO THE REGION.
WITH THIS RIDGE SITTING OVER THE REGION IN THE EVENING AND
OVERNIGHT HOURS...WINDS WILL GO CALM WITH SKIES CLEARING OUT.
WITH A FRESH RAINFALL POSSIBLE ACROSS MUCH OF THE REGION THIS
MORNING...EXPECT THAT THERE MAY BE SOME FOG THAT DEVELOPS
TONIGHT/TOMORROW MORNING. 29.00Z NAM/GFS FORECAST SOUNDINGS
SUPPORT THIS IDEA AS WELL WITH LIGHT WINDS LESS THAN 10KTS UP TO
AROUND 5KFT AND SURFACE DEW POINT DEPRESSIONS DOWN TO AROUND 1C BY
3Z TONIGHT. CONFIDENCE WAS NOT HIGH ENOUGH AT THIS POINT TO PUT A
WIDESPREAD MENTION IN THE FORECAST THOUGH HAVE PUT SOME IN ACROSS
THE VALLEY REGIONS.
THE FOCUS THEN GOES TO THE NEXT TROUGH THAT DIGS TO THE SOUTHEAST
ACROSS SOUTH CENTRAL CANADA INTO THE NORTHERN GREAT LAKES ON
MONDAY. THIS FEATURE PULLS A COLD FRONT DOWN ALONG WITH IT WITH
THE QUESTION BEING HOW FAR SOUTHWEST ALONG THE FRONT WILL
CONVECTION DEVELOP. THE LOW LEVEL MOISTURE TRANSPORT SOURCE FOR
THIS SYSTEM IS THE NORTHERN PLAINS WITH THE GULF CUT OFF BY THE
RIDGE TO THE SOUTH...WHICH MEANS THAT THERE IS NOT MUCH MOISTURE
AVAILABLE TO WORK WITH. THE TIMING ISSUES BETWEEN THE MODELS
APPEAR TO BECOMING LESS WITH THE TREND GOING TOWARD THE FASTER
NAM. ACCORDING TO THE 29.00Z NAM...THE MAIN LIFT IS IN THE LOW
LEVELS AHEAD OF THE COLD FRONT AHEAD OF WHEN THE MID LEVEL TROUGH
MOVES IN...SO THERE SHOULD NOT BE MUCH UPPER LEVEL INFLUENCE HERE.
INSTABILITY IS DECENT IN THE 1000-2000 J/KG RANGE WITH THE NAM/GFS
LIKELY OVER-FORECASTING THE SBCAPE DUE THEIR SURFACE DEW POINTS
BEING IN THE UPPER 60S TO LOW 70S WHEN WE WILL MORE LIKELY BE IN
THE MID 60S. 29.00Z NAM FORECAST SOUNDINGS WOULD ALSO SUGGEST THAT
THE ATMOSPHERE IS CAPPED FROM AN INVERSION AROUND 750MB THAT WOULD
STRENGTHEN WITH LOWER SFC DEW POINTS. BASED ON THIS...HAVE FOCUSED
THE BETTER CHANCES TO CENTRAL WISCONSIN WHERE THE COMBINATION OF
FORCING AND LESS OF A CAP MAY LEAD TO SOME CONVECTION BUT HAVE
LEFT SOME SLIGHT CHANCES IN TO THE SOUTHWEST ALONG THE FRONT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
306 AM CDT SUN JUL 29 2012
NOT MUCH CONFIDENCE IN THE LATER PART OF THE WEEK WITH THE UPPER
LEVEL FLOW EXPECTED TO BECOME MORE ZONAL TOWARD NEXT WEEKEND.
SURFACE HIGH PRESSURE WILL BE IN PLACE WEDNESDAY BEFORE A COLD
FRONT DROPS DOWN INTO THE REGION WEDNESDAY NIGHT AND THURSDAY.
THIS FRONT THEN APPEARS TO STALL OUT ACROSS THE REGION WHICH KEEPS
PRECIPITATION CHANCES AROUND THROUGH THE REST OF THE WEEK. SOME
TIMING DIFFERENCES WITH THE FRONT VIA THE 29.00Z GFS/ECMWF LEADS
TO HAVING THE CHANCES THROUGH THE WEEK THOUGH THERE WILL LIKELY BE
SOME BREAKS AT TIMES. TEMPERATURE-WISE IT STILL LOOKS FAIRLY
SEASONAL WITH NOT MUCH IN THE WAY OF CHANGES DUE TO WEAK LOW LEVEL
WARM AIR ADVECTION.
&&
.AVIATION...THROUGH 06Z MONDAY
1149 PM CDT SAT JUL 28 2012
CONTINUED THE PESSIMISTIC TREND OF MVFR CIGS/VSBYS AT KRST AND
TEMPO MVFR CIGS AT KLSE. CONFIDENCE IS HIGHER THAT A WEATHER
SYSTEM MOVING FROM ERN SD WILL MOVE IN AND DEVELOP SHRA OVERNIGHT
HOWEVER JUST HOW LOW THE CIG/VSBY WILL GET AT THE SITES IS OF
LOWER CONFIDENCE. THERE MAY ALSO BE THUNDER NEAR/AT THE TAF
HOWEVER THE CONFIDENCE IS LOW ON THIS OCCURRENCE AS THE INSTABILITY
IS ONLY IN THE 100-300 J/KG RANGE AND THE HIGH RESOLUTION MODEL
GUIDANCE DOESNT KEEP TSRA ACTIVITY FAR ENOUGH EAST TO AFFECT TAF
SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CDT SUN JUL 29 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1052 AM EDT SUN JUL 29 2012
.UPDATE...
MSAS DEW POINT AND PRESSURE ANALYSIS INDICATES THE FRONT IS
SITUATED ACROSS CENTRAL GEORGIA...BETWEEN ATL AND THE CSG TO MCN
AREA. FORECAST THINKING IS STILL ON TRACK WITH BEST PRECIP CHANCES
ALONG AND SOUTH OF THE FRONT SO NO CHANGES TO THE AFTERNOON POPS.
FORECAST IS OVERALL IN LINE WITH THE 11Z HRRR RUN SHOWING ISOLATED
DEVELOPMENT ACROSS NORTH GEORGIA WITH HIGHER COVERAGE ACROSS THE
SOUTHERN THIRD OF THE FORECAST AREA.
ONLY TWEAKS TO THE FORECAST ARE BASED ON CURRENT TEMP...DEW POINT
AND RADAR TRENDS. CUT DOWN ON POPS ACROSS CENTRAL GEORGIA FOR THE
REST OF THE MORNING AS THE AREA OF SHOWERS THAT PERSISTED THROUGH
MUCH OF THE MORNING HAS DISSIPATED.
11
&&
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
LATEST SURFACE ANALYSIS SHOWS SURFACE FRONT HAS MADE ITS WAY INTO
THE ATLANTA METRO AREA WITH LOW END SCATTERED COVERAGE OF SHOWERS
AND VERY ISOLATED THUNDERSTORMS MARKING ITS LEADING EDGE. HAVE
MADE SOME MINOR INITIAL GRID MODIFICATIONS TO TAKE POPS THROUGH
12Z. OTHERWISE...AREA IS UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES
WITH INITIALIZED UPPER LEVELS SHOWING CONTINUED TROUGH DEVELOPMENT
IN THE TENNESSEE VALLEY AND INTO THE LOCAL AREA.
FOR THE REMAINDER OF TODAY...ANTICIPATE MAIN DEVELOPMENT TO BE
ALONG THE MAIN FRONT AND ENHANCED POPS EXPECTED WITH AFTERNOON
HEATING. THIS WILL GENERALLY OCCUR OVER SOUTHERN SECTIONS OF THE
FORECAST AREA AND WILL FOCUS HIGHEST GRIDDED POPS THERE. CONTINUE
TO WATCH AREA ALONG THE FRONT OF ENHANCED DOWNDRAFT CAPE WITH
CLOSE TO 1000 J/KG ACCOUNTING FOR NUMEROUS OUTFLOWS SEEN ON RADAR
DESPITE SHALLOW CORES. ANTICIPATING THIS AREA TO SHIFT SOUTH WITH
SOME THREAT OF AN ISOLATED SEVERE WIND GUST IN STRONGEST ACTIVITY
THIS AFTERNOON.
EXPECTING SOME DRY AIR TO MIX DOWN THIS AFTERNOON BUT WITH TEMPS
LIKELY SLIGHTLY ABOVE GUIDANCE AGAIN...WILL SEE SOME ISOLATED HEAT
INDICES ABOVE 105. LIKE YESTERDAY...NOT EXPECTING WIDESPREAD
ENOUGH CONDITIONS TO WARRANT ADVISORY.
FOR MONDAY...STILL A GOOD DEAL OF DRY AIR IN PLACE AT THE MID
LEVELS TO INHIBIT CONVECTION INITIALLY. HOWEVER...A LATE ARRIVING
SHORTWAVE LOOKS TO PROVIDE TO FOCUS FOR ENHANCED ACTIVITY AND WILL
GO ABOVE GUIDANCE FOR POPS WITH LOW END CHANCE.
DEESE
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
DISSIPATING STATIONARY FRONT OR SURFACE TROUGH ACROSS THE AREA TO
START THE LONG TERM WITH AN UPPER TROUGH ALONG THE EASTERN SEABOARD.
MODELS INDICATING THE POTENTIAL FOR SHORT WAVES IN THE NW FLOW ALOFT
TO AFFECT THE AREA MONDAY NIGHT AND TUESDAY ALLOWING FOR THE CHANCE
OF SHOWERS AND THUNDERSTORMS. THIS POTENTIAL FOR SHORT WAVES TO
AFFECT THE FORECAST AREA LOOKS TO CONTINUE WEDNESDAY AND THURSDAY.
ON FRIDAY THE UPPER RIDGE BEGINS TO BUILD AND LOOKS TO CONTINUE OVER
THE AREA THE REST OF THE LONG TERM. THIS SHOULD DIMINISH SOME THE
OVERALL POTENTIAL FOR SHOWERS AND THUNDERSTORMS WITH A HIGHLY
DIURNAL NATURE TO ANY CONVECTION.
HIGH TEMPERATURES SHOULD MODERATE SOME FOR THE FIRST PART OF THE
LONG TERM WITH HIGHS IN THE LOWER HALF OF THE 90S ON THE HIGH SIDE
AND THEN WARM TO THE UPPER HALF OF THE 90S TO NEAR 100 AT WEEKS END.
BDL
AVIATION...
12Z UPDATE...
/ISSUED 741 AM EDT SUN JUL 29 2012/
FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE ATL AREA TERMINALS AND
ANTICIPATE VFR CONDITIONS FOR THE REMINDER OF THIS CYCLE. WILL KEEP
PROB30 FOR NOW FOR CSG AND MCN AS FRONT PUSHES THROUGH AT TIME OF
MAX HEATING.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON ALL ELEMENTS
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 97 70 96 72 / 20 20 30 20
ATLANTA 96 73 94 75 / 20 20 30 20
BLAIRSVILLE 89 63 89 66 / 20 20 20 40
CARTERSVILLE 93 64 95 70 / 20 20 30 40
COLUMBUS 97 74 97 75 / 40 30 30 20
GAINESVILLE 93 71 92 72 / 20 20 30 30
MACON 97 72 96 73 / 40 30 30 20
ROME 94 64 95 70 / 20 20 30 40
PEACHTREE CITY 94 67 95 70 / 20 20 30 20
VIDALIA 93 75 96 75 / 40 40 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT SUN JUL 29 2012
.DISCUSSION...
ISSUED 1045 AM CDT SUN JUL 29 2012
FORECAST LOOKS FAIRLY GOOD TODAY AND JUST A FEW ADJUSTMENTS NEEDED
LIKE INCREASING CLOUD COVER A BIT MORE SIMILAR TO YESTERDAY WITH
PARTLY TO MOSTLY CLOUDY SKIES OVERALL. HIGHS IN THE MID TO UPPER 80S
WITH LOWER 90S OVER SW AREAS. CONTINUED 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON WHILE KEEPING AREAS EAST OF I-57
DRY. NAM AND HRRR MODELS IN BETTER AGREEMENT WITH SOME QPF OVER
WESTERN AREAS THIS AFTERNOON AND THIS IS SUPPORTED BY CURRENT FORECAST.
MOST SHOWERS AND ISOLATED THUNDERSTORMS STAYED SW OF CENTRAL IL
THIS MORNING OVER SW IL INTO EASTERN MO AND DRIFTING SE INTO THE
MID MS VALLEY. WEAK LOW PRESSURE 1013 MB NEAR THE IA/NE BORDER TO
TRACK SE TOWARD ST LOUIS BY 12Z/MON AND TO REDEVELOP ISOLATED TO
SCATTERED CONVECTION THIS AFTERNOON AND INTO TONIGHT OVER WESTERN
AREAS. SPC HAS 5% RISK OF SEVERE STORMS OVER WESTERN AREAS LATER
THIS AFTERNOON AND EVENING.
KH
&&
.AVIATION...
ISSUED 605 AM CDT SUN JUL 29 2012
DESPITE AN AREA OF SHOWERS APPROACHING FROM THE WEST THIS
MORNING...WE ARE STILL EXPECTING VFR CONDITIONS THROUGH THIS
FORECAST PERIOD (THRU 12Z MONDAY). JUST HOW FAR EAST THE RAIN
WILL GET THIS MORNING IS THE MAIN FORECAST CHALLENGE EARLY ON IN
THIS FORECAST...AND THEN WHETHER OR NOT WE WILL SEE ANY REDEVELOPMENT
LATER THIS AFTN AND EVENING AS A WEATHER SYSTEM SLOWLY PUSHES ACRS
THE AREA. AREAS OUT TO OUR WEST WHERE IT HAS BEEN RAINING FOR A
WHILE STILL ARE REPORTING VFR CIGS WITH BASES AVERAGING FROM
7000-10000 FEET. BASED ON THE LATEST SHORT TERM MODEL RUNS...WILL
CONTINUE TO INCLUDE THE SHOWER CHANCES IN THE TAFS FOR SPI AND PIA
ONLY AND WAIT AND SEE IF THE RAIN CAN ADVANCE ANY FURTHER EAST.
AFTER THIS BATCH OF PRECIP WINDS DOWN...WILL HOLD OFF INCLUDING
ANYTHING OTHER THAN A VCTS AND CB GROUP AT SPI AND DEC LATE THIS
AFTN AND EVENING AS THOSE TWO SITES WILL BE CLOSER TO THE MORE
UNSTABLE AIR MASS WHICH WILL BE ACRS NE MO INTO EXTREME SW IL.
SURFACE WINDS WILL VEER INTO A SOUTHERLY DIRECTION TODAY AT 10 TO
15 KTS...WITH POSSIBLY A FEW GUSTS TO NEAR 20 KTS...ESP AT PIA AND
SPI WHICH WILL BE CLOSER TO THE RAIN THIS MORNING. WINDS ARE THEN
EXPECTED TO BACK INTO MORE OF A SOUTHEAST DIRECTION TONIGHT AT 5
TO 10 KTS.
SMITH
&&
.PREV DISCUSSION...
ISSUED 254 AM CDT SUN JUL 29 2012
AT 06Z HIGH PRESSURE STILL OCCUPIED THE GREAT LAKES AND THIS
PROVIDED A CALM AND SEASONABLE NIGHT ACROSS CENTRAL IL. FARTHER
WEST POORLY ORGANIZED BROAD LOW PRESSURE STRETCHED ACROSS THE
CENTRAL PLAINS. ALOFT...NORTHWEST FLOW DOMINATED MUCH OF THE
MIDWEST. CONVECTION AS CLOSE AS SE IA/NE MO WAS OCCURRING AHEAD OF A
SHORTWAVE DROPPING INTO SW MN...AND ALONG A MID LEVEL THETA-E
GRADIENT AND AREA OF 850MB MOISTURE CONVERGENCE. AS THIS AREA OF
LIFT AND CONVERGENCE SHIFTS SOUTHEAST TODAY THUNDERSTORM CHANCES
WILL RETURN TO THE FORECAST.
SHORT TERM...TODAY THROUGH MONDAY
EXPECT SCATTERED CONVECTION TO PUSH INTO THE WESTERN CWA AFTER SUNRISE
AND GRADUALLY DIMINISH THROUGH THE MORNING AS MID LEVEL CONVERGENCE
WANES. THEREFORE HAVE HIGHEST POPS IN THE FAR WEST QUICKLY
TAPERING TO SLIGHT CHANCE FOR THE CENTRAL AND EASTERN CWA. LIFT
AHEAD OF THE SHORTWAVE DROPPING IN FROM THE NORTHWEST COULD KEEP
ISOLATED TO SCATTERED CONVECTION GOING INTO THE AFTERNOON BUT DO
NOT ANTICIPATE HIGH COVERAGE. WHILE INSTABILITY IS LIMITED /MUCAPES
700-900 J/KG/...SHEAR IS MORE IMPRESSIVE DUE TO SOUTHERLY SURFACE
WINDS AND WESTERLY FLOW ALOFT WHICH CONTRIBUTES TO 40 KTS OF BULK
SHEAR. SO SOME THUNDERSTORM ORGANIZATION IS POSSIBLE WITH STRONGER
CELLS CAPABLE OF SMALL HAIL OR BRIEF GUSTY WINDS...MOST FAVORED IN
THE SOUTHWEST CWA. WITH THE LIKELIHOOD OF INCREASED CLOUD COVER
WILL TAKE A FEW DEGREES OFF MET GUIDANCE...FOR HIGHS IN THE UPPER
80S TO LOWER 90S.
AS HAS BEEN THE CASE THE PAST COUPLE DAYS TO OUR NORTHWEST...THE
AREA OF LIFT VERY SLOWLY DRIFTS SOUTHEAST SO WILL MAINTAIN LOW
CHANCE POPS FOR AREAS EAST OF THE IL RIVER SUNDAY NIGHT...AND THE
SOUTHEAST THIRD INTO MONDAY MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY
BEHIND THE DEPARTING SYSTEM...HIGH PRESSURE BUILDING INTO THE
GREAT LAKES PROVIDES LIGHT NORTHERLY FLOW INTO MID-WEEK. 850 MB
TEMPS REMAIN QUITE WARM...ABOVE 20C SO WILL KEEP TEMPS A FEW
DEGREES ABOVE NORMAL. INTERESTING THAT MET GUIDANCE ALREADY PUSHES
HIGHS ABOVE 100 BY TUESDAY FOR SOUTHERN HALF OF THE AREA...BUT
GIVEN LIGHT FLOW/LIMITED MIXING WILL KNOCK A FEW DEGREES OFF
THESE NUMBERS.
NORTHWEST FLOW ALOFT CONTINUES TO DOMINATE THE WEATHER PATTERN
THROUGH THE REMAINDER OF THE EXTENDED FORECAST. DUE TO MODEL
DIFFERENCES IN TIMING AND LOCATION OF ANY SHORTWAVES...AND RECENT
TRENDS/DROUGHT WILL KEEP THE FORECAST DRY UNTIL A MORE SUBSTANTIAL
TROUGH SHIFTS INTO THE GREAT LAKES TOWARDS SATURDAY. TEMPERATURES
LOOK TO STAY SEVERAL DEGREES ABOVE NORMAL INTO NEXT WEEKEND.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
544 AM MDT SUN JUL 29 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MAIN FORECAST PROBLEM WILL BE PRECIPITATION CHANCES THROUGH THE
SHORT TERM. SATELLITE SHOWING THE FLOW HAS DEAMPLIFIED OVER THE LAST
24 HOURS ACROSS MOST OF THE PACIFIC. THIS FLOW THEN TRANSITIONS TO
THE UPPER TROUGH NEAR THE WEST COAST WITH PERSISTENT/BROAD UPPER
RIDGE REMAINING ANCHORED OVER THE CENTER OF THE COUNTRY. CENTER OF
THIS RIDGE HAS MOVED SOUTHEAST FROM YESTERDAY...HOWEVER THE RIDGE HAS
ELONGATED TO THE NORTHWEST.
SATELLITE/UPPER AIR ANALYSIS SHOWS STRONG SUBTROPICAL MOISTURE FEED
AROUND THE WEST AND NORTHERN PORTION OF THE HIGH. BESIDES A SMALL
INCREASE IN MID LEVEL MOISTURE...THE AIR MASS REMAINS NEARLY THE
SAME FROM YESTERDAY. AT MID LEVELS...THE GFS/UKMET WERE DOING A
LITTLE BETTER THAN THE CANADIAN/SREF WITH THE NAM INITIALIZING THE
WORST OF THE BUNCH...ESPECIALLY ON THE CENTER POSITION OF THE RIDGE.
ONGOING CONVECTION AND OUTFLOW BOUNDARIES MAKING A LITTLE HARDER TO
GET A GOOD HANDLE ON THE SURFACE. THE SREF/RUC/HRRR WERE CATCHING
BETTER THAN THE NAM AND ECMWF. MODELS WERE PRETTY CLOSE ON THE LOW
LEVEL THERMAL FIELD. THE NAM/CANADIAN/SREF WERE DOING SLIGHTLY
BETTER.
NAM THROUGH 06Z HAS PRECIPITATION COVERAGE UNDERDONE THAT WAS
OVER/NEAR THE EAST/SOUTHEAST PORTION OF THE AREA. IT PUT MORE
EMPHASIS/PRECIPITATION ON THE WESTERN END OF THE SURFACE THAN IN THE
EAST. TO SOME EXTENT ALL THE MODELS SHOW THAT BIAS. THE SREF AND TO
A LESSER EXTENT THE CANADIAN GOT THAT PRECIPITATION RIGHT. FROM
YESTERDAY...THE RUC AND HRRR STARTED THE PRECIPITATION FURTHER NORTH
AND EAST AND WAS THE MOST CORRECT. THE HRRR TONIGHT IS CATCHING THE
CURRENT PRECIPITATION AREA IN THE EAST WELL.
TODAY/TONIGHT...OVERNIGHT CONVECTION WILL PROBABLY LEAVE AROUND
LEFTOVER BOUNDARIES. MOST MODELS ARE INSISTENT OF STARTING CONVECTION
BY 18Z. SURFACE BOUNDARY NEAR THE SOUTHERN PORTION OF THE AREA WITH
A WEAK SHORTWAVE TROUGH NEAR THE WESTERN PORTION OF THE AREA AT THE
BEGINNING OF THE DAY AS WELL. MODELS HAVE BEEN SIMILAR IN HAVING
THE BEST CHANCE OF PRECIPITATION IN THE WEST AND NORTHERN PORTION OF
THE AREA. SREF AND GEFS PROBABILITIES MATCH UP WHERE THE DEEPEST
LIFT IS. SO ADJUSTED THE CHANCE POPS FURTHER EAST.
MODELS STILL SHOWING IT WARM TODAY. KEPT IT CLOSE TO WHAT THE
WARMEST GUIDANCE WHICH WAS CLOSE TO THE PREVIOUS FORECAST.
MONDAY...THERE LOOKS TO BE SOME LINGERING STORMS IN THE MORNING
IN THE EAST. AFTER THAT MODELS STILL HAVING TROUBLE WITH THIS DAY ON
THE PRECIPITATION. LIFT REMAINS AROUND ALL DAY AT MID LEVELS WITH
SURFACE SYNOPTIC TROUGH HANGING AROUND SOMEWHERE IN THE AREA WITH
POSSIBLE MESOSCALE BOUNDARIES AND WITH LITTLE TO NO CINH MAKE IT
POSSIBLE FOR THUNDERSTORMS TO BREAK ABOUT ANYWHERE IN THE
AFTERNOON. SO AGAIN BROADBRUSHED SLIGHT CHANCES. EASTERLY WINDS...
AND LINGERING CLOUD COVER AND WITH SLIGHTLY COOLER 850 MB
TEMPERATURES MAKE FOR A LITTLE COOLER DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 541 AM MDT SUN JUL 29 2012
AT THIS TIME VFR CONDITIONS ARE EXPECTED AT BOTH TAF SITES. SUBTLE
AND COMPLEX DETAILS AT BOTH SURFACE AND ALOFT MAKE THIS A HARD
FORECAST TO GET A HANDLE ON ANYTHING. COULD BE SOME LIGHT SHOWERS
NEAR KGLD THIS MORNING. BECAUSE OF UNCERTAINTY CHOSE TO HANDLE
THUNDERSTORM FORECAST WITH VCTS. THE BEST CHANCE FOR THUNDERSTORMS
TO AFFECT A TAF SITE AND CAUSE SUB VFR CONDITIONS WILL BE AT KMCK.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BULLER/PMM
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
405 AM MDT SUN JUL 29 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MAIN FORECAST PROBLEM WILL BE PRECIPITATION CHANCES THROUGH THE
SHORT TERM. SATELLITE SHOWING THE FLOW HAS DEAMPLIFIED OVER THE LAST
24 HOURS ACROSS MOST OF THE PACIFIC. THIS FLOW THEN TRANSITIONS TO
THE UPPER TROUGH NEAR THE WEST COAST WITH PERSISTENT/BROAD UPPER
RIDGE REMAINING ANCHORED OVER THE CENTER OF THE COUNTRY. CENTER OF
THIS RIDGE HAS MOVED SOUTHEAST FROM YESTERDAY...HOWEVER THE RIDGE HAS
ELONGATED TO THE NORTHWEST.
SATELLITE/UPPER AIR ANALYSIS SHOWS STRONG SUBTROPICAL MOISTURE FEED
AROUND THE WEST AND NORTHERN PORTION OF THE HIGH. BESIDES A SMALL
INCREASE IN MID LEVEL MOISTURE...THE AIR MASS REMAINS NEARLY THE
SAME FROM YESTERDAY. AT MID LEVELS...THE GFS/UKMET WERE DOING A
LITTLE BETTER THAN THE CANADIAN/SREF WITH THE NAM INITIALIZING THE
WORST OF THE BUNCH...ESPECIALLY ON THE CENTER POSITION OF THE RIDGE.
ONGOING CONVECTION AND OUTFLOW BOUNDARIES MAKING A LITTLE HARDER TO
GET A GOOD HANDLE ON THE SURFACE. THE SREF/RUC/HRRR WERE CATCHING
BETTER THAN THE NAM AND ECMWF. MODELS WERE PRETTY CLOSE ON THE LOW
LEVEL THERMAL FIELD. THE NAM/CANADIAN/SREF WERE DOING SLIGHTLY
BETTER.
NAM THROUGH 06Z HAS PRECIPITATION COVERAGE UNDERDONE THAT WAS
OVER/NEAR THE EAST/SOUTHEAST PORTION OF THE AREA. IT PUT MORE
EMPHASIS/PRECIPITATION ON THE WESTERN END OF THE SURFACE THAN IN THE
EAST. TO SOME EXTENT ALL THE MODELS SHOW THAT BIAS. THE SREF AND TO
A LESSER EXTENT THE CANADIAN GOT THAT PRECIPITATION RIGHT. FROM
YESTERDAY...THE RUC AND HRRR STARTED THE PRECIPITATION FURTHER NORTH
AND EAST AND WAS THE MOST CORRECT. THE HRRR TONIGHT IS CATCHING THE
CURRENT PRECIPITATION AREA IN THE EAST WELL.
TODAY/TONIGHT...OVERNIGHT CONVECTION WILL PROBABLY LEAVE AROUND
LEFTOVER BOUNDARIES. MOST MODELS ARE INSISTENT OF STARTING CONVECTION
BY 18Z. SURFACE BOUNDARY NEAR THE SOUTHERN PORTION OF THE AREA WITH
A WEAK SHORTWAVE TROUGH NEAR THE WESTERN PORTION OF THE AREA AT THE
BEGINNING OF THE DAY AS WELL. MODELS HAVE BEEN SIMILAR IN HAVING
THE BEST CHANCE OF PRECIPITATION IN THE WEST AND NORTHERN PORTION OF
THE AREA. SREF AND GEFS PROBABILITIES MATCH UP WHERE THE DEEPEST
LIFT IS. SO ADJUSTED THE CHANCE POPS FURTHER EAST.
MODELS STILL SHOWING IT WARM TODAY. KEPT IT CLOSE TO WHAT THE
WARMEST GUIDANCE WHICH WAS CLOSE TO THE PREVIOUS FORECAST.
MONDAY...THERE LOOKS TO BE SOME LINGERING STORMS IN THE MORNING
IN THE EAST. AFTER THAT MODELS STILL HAVING TROUBLE WITH THIS DAY ON
THE PRECIPITATION. LIFT REMAINS AROUND ALL DAY AT MID LEVELS WITH
SURFACE SYNOPTIC TROUGH HANGING AROUND SOMEWHERE IN THE AREA WITH
POSSIBLE MESOSCALE BOUNDARIES AND WITH LITTLE TO NO CINH MAKE IT
POSSIBLE FOR THUNDERSTORMS TO BREAK ABOUT ANYWHERE IN THE
AFTERNOON. SO AGAIN BROADBRUSHED SLIGHT CHANCES. EASTERLY WINDS...
AND LINGERING CLOUD COVER AND WITH SLIGHTLY COOLER 850 MB
TEMPERATURES MAKE FOR A LITTLE COOLER DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1147 PM MDT SAT JUL 28 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT KMCK AND KGLD.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO MOVE INTO THE AREA
FROM THE WEST DURING THE AFTERNOON AND EVENING. HAVE INTRODUCED A
PROB30 GROUP INTO THE KGLD TAF BETWEEN 22Z-04Z SUNDAY
EVENING...BUT HAVE LEFT KMCK WITHOUT A MENTION OF THUNDERSTORMS
SINCE PROBABILITIES OF THUNDERSTORM DEVELOPMENT ARE LESS FURTHER
EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BULLER/PMM
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
724 AM EDT SUN JUL 29 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 724 AM EDT SUN JUL 29 2012
EXPECT VFR CONDITIONS/LGT WINDS TODAY WITH HI PRES DOMINATING. THE
APRCH OF A DISTURBANCE LATER TNGT MAY BRING SOME SOME SHRA/TS TO
MAINLY CMX...BUT CONCERNS ABOUT SUFFICIENT MSTR RETURN/TIMING AND
COVERAGE DO NOT ALLOW FOR A FCST OF MORE THAN VCSH ATTM. VFR
CONDITIONS SHOULD BE THE RULE TNGT AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
610 AM CDT SUN JUL 29 2012
.UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...
SHORT WAVE NEAR WILLMAR THIS MORNING HAS DRIVEN SHOWERS ACROSS THE
AREA THIS PAST NIGHT. ELEVATED SHOWERS ACROSS WRN WI OVER TO THE
NRN TWIN CITIES ARE WITHIN A ZONE OF WEAK FGEN/ISENTROPIC LIFT
AROUND H6...ACTIVITY WEST OF THE CITIES IS ASSOCIATED WITH THE
SHORTWAVE...WHILE MOST ROBUST AREA OF CONVECTION ACROSS SOUTH
CENTRAL MINNESOTA IS ON THE NOSE OF THE LLJ. THE RAP SHOWS THIS
UPPER WAVE REACHING LA CROSSE BY 15Z...WITH ASSOCIATED FORCING
MOVING TO THE SOUTHEAST THROUGH THE REST OF THE MORNING. SRN MN
CONVECTION WILL CERTAINLY CONTINUE TO FOCUS BRUNT OF PRECIP TO THE
SOUTH...BUT SHOULD CONTINUE TO SEE LIGHT SHOWERS FOLLOW THE H7/H5
LOW SE ACROSS THE AREA THIS MORNING...WITH A MAJORITY OF RAIN
FALLING ALONG AND SOUTH OF I-94. BASED ON RAP TIMING OF THE
SHORTWAVE AND REFLECTIVITY FORECASTS FROM MOST CAMS...EXPECT MOST
OF THIS PRECIP TO BE OUT OF THE MPX CWFA BY 15Z. IN THE RAINS
WAKE...SKIES WILL BE CLEARING OUT FROM WEST TO EAST. H85 TEMPS
WILL RANGE FROM AROUND +22C WEST TO +16 EAST...WHICH SHOULD ALLOW
FOR LOWER 90S TO LOWER 80S FOR HIGHS RESPECTIVELY.
FOR TONIGHT...STRONG WAVE CURRENTLY SPINNING ACROSS SRN SASK WILL
RUN ALONG THE MN/ONTARIO BORDER...DRIVING A COLD FRONT INTO NRN
MN. CAMS AND SREF PROBS ALL SIMILAR WITH DEVELOPING SCT STORMS
ALONG THE FRONT THIS AFTERNOON FROM ERN NODAK INTO NW MN. THIS
FRONT WILL BE MOVING INTO CENTRAL MN BY 12Z MONDAY...SO INTRODUCED
SOME SMALL POPS ACROSS CENTRAL MN LATE TONIGHT TO ACCOUNT FOR
THAT. DURING THE DAY MONDAY...THIS FRONT WILL DROP ACROSS THE
AREA...EXITING THE S/SE MPX CWFA BETWEEN 21Z AND 00Z. BEST FLOW AT
H85 AND CONVERGENCE ALONG THE BOUNDARY STILL PEGGED TO BE ACROSS
THE U.P. OF MICH INTO NRN WI...WHERE GREATEST POTENTIAL FOR STORMS
WILL EXIST. CONTINUED A NARROW RIBBON OF SLIGHTS ALONG THE FRONT
MONDAY AFTERNOON WITH THE NAM ADVERTISING 2-3000 J/KG OF MUCAPE
ALONG THE FRONT. GIVEN THE FRONTS EXPECTED MOVEMENT...DID TRIM
BACK HOW FAR NORTH POPS ARE MENTIONED MONDAY AFTERNOON. ALSO LOOKS
WARM AGAIN MONDAY...WITH H85 TEMPS WARMING INTO THE 20S C FOR MOST
OF THE AREA...CONTINUED TO ADVERTISE UPPER 80S TO LOWER 90S HIGHS
MONDAY AFTERNOON...WITH 90S CREEPING UP TO ABOUT I-94.
FOR THE REST OF THE FORECAST...WILL BE REMAINING NORTH OF THE MAIN
UPPER RIDGE...WELL WITHIN THE JET STREAMS TERRITORY. STILL LOOKING
AT TWO POTENTIAL ACTIVE PERIODS IN THE TUESDAY THROUGH SUNDAY
TIMEFRAME. THE FIRST WILL BE ANOTHER WEAK NW FLOW WAVE THE MODELS
SHOW CRESTING THE RIDGE WEDNESDAY INTO WEDNESDAY NIGHT...SENDING A
VERY WEAK BOUNDARY ACROSS THE REGION. LIKE MONDAYS FRONT...H85
FLOW WILL BE LACKING WITH THE WEDNESDAY WAVE...AND PRECIP CHANCES
ARE LOOKING SCANT AT BEST WITH THIS WAVE...SO CONTINUED TO CAP
POPS AT 40 PERCENT...WITH BEST CHANCES RUNNING ACROSS CENTRAL MN
INTO WRN WI...WHICH IS WHERE THE ECMWF SHOWS THE SRN END OF A LLJ
WORKING THROUGH.
SHOULD SEE ANOTHER BREAK FROM THE PRECIP ACROSS THE AREA
THURSDAY...BEFORE A MORE SIGNIFICANT UPPER WAVE MOVES ACROSS THE
UPPER MS VALLEY SOMETIME ON FRIDAY /ECMWF AND GEM/ OR SATURDAY
/GFS/. ECMWF IS MOST AGGRESSIVE WITH THE WAVE...BRING A NEUTRAL TO
NEG TILTED TROUGH THROUGH...WITH THE GFS SHOWING A WEAKER
POSITIVELY TILTED TROUGH WORKING THROUGH SATURDAY. GIVEN TIMING
DIFFERENCES...BLENDING PROCEDURE ENDED UP SMEARING CHANCE POPS
ACROSS BOTH DAYS. HOWEVER...DESPITE THE TIMING DIFFERENCES...BOTH
THE GFS AND ECMWF SHOW THIS FRONT PACKING QUITE A PUNCH IN TERMS
OF COOLER/DRIER AIR BEHIND IT...WITH BOTH ADVERTISING A 1020 MB
HIGHS SETTLING IN BEHIND THIS SYSTEM. TILL THEN THOUGH...HIGHS IN
THE MID 80S TO LOWER 90S WILL BE THE NORM.
.CLIMATE...
QUICK CHECK THROUGH THE CLIMATE DATA FOR THE TWIN CITIES FOR
NUMBER OF DAYS IN A MONTH WHERE HIGHS WERE BELOW 80 SHOWS THAT
THERE HAS NEVER BEEN A MONTH IN THE TWIN CITIES WHERE THERE WAS
NOT AT LEAST ONE DAY WITH A HIGH LESS THAN 80 /JULY OF 1936 AND
1916 BOTH HAD ONE SUB 80 DEGREE DAY/. TO THIS POINT...THE
"COLDEST" HIGH THIS MONTH WAS AN 80 ON THE 27TH. BASED ON CURRENT
FORECAST...THIS JULY LOOKS LIKE IT WILL BE THE FIRST MONTH IN
RECORDED HISTORY FOR THE TWIN CITIES WHERE WE FAILED TO SEE AT
LEAST ONE DAY LESS THAN 80. THE LAST SUB 80 HIGH WAS BACK ON JUNE
25TH.
&&
.AVIATION.../12Z TAF ISSUANCE/
MAIN CONCERN EARLY IS THREAT OF MVFR CIGS/VSBYS AS SHRA MOVES
THROUGH. CONTINUED THE TREND OF DRIVING SYSTEM INTO WISCONSIN AFTER
14Z...ENDING BY 17Z AT KEAU. WILL LIKELY SEE PERIOD OF MVFR CIGS
OVER EASTERN AREAS THROUGH 18Z. THEN SHOULD SEE CUMULUS LIFT INTO
THE AFTERNOON AND DISSIPATE BY EVENING. SOUTHWEST WINDS AHEAD OF
RAIN AREA...THEN BECOMING LIGHT SOUTHEAST OVER MUCH OF THE AREA THE
REST OF THE DAY. OVERNIGHT...WITH LIGHT WINDS AND MAINLY HIGH
CLOUDS...COULD SEE FOG DEVELOP...ESPECIALLY OVER EASTERN AREAS/WI.
MENTIONED FOR MVFR VSBYS IN BR AT KSTC/KRNH AND KEAU...MAINLY
09Z-12Z. COLD FRONT SWEEPS SOUTHEAST AND MOVES THROUGH KMSP BY 18Z
MONDAY. RIGHT NOW...LOOKS LIKE A DRY FROPA WITH WIND SHIFTING TO
THE WEST/NORTHWEST.
KMSP...WAVE MOVING THROUGH THE AREA THROUGH 13Z-14Z...WITH POSSIBLE
TEMPO MVFR CONDITIONS. THEN CLOUDS SHOULD THIN WITH SOME CUMULUS
EXPECTED INTO THE AFTERNOON. CLEARING BY LATE AFTERNOON WITH MORE
MID/HIGH CLOUDS INTO THE AREA LATER TONIGHT. FROPA BY 18Z MONDAY
WITH WINDS SHIFTING TO THE NORTHWEST AND POSSIBLY GUSTY INTO THE
AFTERNOON.
//OUTLOOK
MONDAY... BRIEF MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA IN WI.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR EXPECTED.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/DE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 AM CDT SUN JUL 29 2012
.AVIATION...12Z KGRI TAF. A SURFACE BOUNDARY WILL LINGER ACROSS
THE FORECAST AREA THROUGHOUT THE TAF PERIOD. WHILE VFR CONDITIONS
ARE EXPECTED THROUGHOUT PERIOD...A FEW WEATHER CONCERNS SHOULD BE
MONITORED. LIGHT AND VARIABLE WINDS THIS MORNING WILL TRANSITION
TO THE NORTHEAST BEFORE TURNING TO THE EAST THIS AFTERNOON AND
EVENING. THERE REMAINS A CHANCE FOR ISOLATED SHOWERS AND
THUNDERSTORMS NEAR THE SURFACE BOUNDARY THIS AFTERNOON AND DURING
THE OVERNIGHT HOURS. WHILE THESE SHOWERS REMAIN ISOLATED IN NATURE
AND TOWARDS THE END OF THE PERIOD...WILL LET OTHER SHIFTS CONTINUE
TO MONITOR AND ADD AS NEEDED. ALONG THE BOUNDARY INCREASED CLOUDS
WILL ALSO CONTINUE THIS AFTERNOON WITH A OVERCAST MID LEVEL DECK
EXPECTED OVERNIGHT SHOULD THUNDERSTORMS BE AROUND.
&&
.PREV DISCUSSION... /ISSUED 430 AM CDT SUN JUL 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERNS LIE WITH PRECIPITATION CHANCES...AND TEMPERATURES.
BEEN LITTLE OVERALL CHANGE IN THE UPPER LEVEL PATTERN ACROSS THE
REGION...WITH SATELLITE AND PROFILER DATA SHOWING IT REMAINING
DOMINATED BY UPPER LEVEL HIGH PRESSURE/RIDGING CENTERED JUST WEST
OF THE CWA. THIS LEAVES NORTHWESTERLY FLOW IN PLACE...WITH A
DISTURBANCE SHIFTING SOUTHEAST THIS MORNING...RIDING AROUND THE
EDGE OF THE RIDGE. CONTINUING TO SEE A FEW SHOWERS/THUNDERSTORMS
LINGER IN FAR SWRN PORTIONS OF THE CWA EARLY THIS MORNING
RESULTING FROM THIS DISTURBANCE...BUT EXPECT THEM TO EXIT THE CWA
OVER THE NEXT COUPLE HOURS. SEEING A WEAK SURFACE PATTERN IN PLACE
OVER THE CWA...BRINGING LIGHT AND VARIABLE WINDS EARLY THIS
MORNING...THOUGH A WEAK BOUNDARY IS IN PLACE JUST SOUTH OF THE
CWA.
FOR TODAY AND TONIGHT...NO SIGNIFICANT CHANGES WERE MADE TO THE
INHERITED FORECAST. KEPT THE FIRST HALF THE DRY QUIET...WITH
THUNDERSTORM CHANCES RETURNING DURING THE LATE AFTERNOON AND INTO
THE OVERNIGHT HOURS. MODELS NOT IN TOO BAD OF AGREEMENT SHOWING
THE SURFACE BOUNDARY REMAINING NEAR/JUST SOUTH OF THE CWA
THROUGH THE DAYTIME HOURS...AND AS ANOTHER WEAK UPPER LEVEL
DISTURBANCE LOOKS TO ROUND THE EDGE OF THE RIDGE AND MOVE INTO THE
REGION...THUNDERSTORM CHANCES WILL INCREASE. TIMING/OVERALL
COVERAGE REMAINS UNCERTAIN...LITTLE MORE DIFFERENCE BETWEEN
MODELS...NAM CONTINUES TO SHOW AN EARLIER ONSET OF ACTIVITY...VS
OTHERS LIKE THE 06Z HRRR WHICH IS QUIET THRU 21Z...AND THE 00Z 4KM
WRF WHICH SHOWS VERY LITTLE GOING ON AT ALL. BECAUSE OF THESE
DIFFERENCES KEPT POPS THOUGH TONIGHT LOW. COULD SEE A FEW
THUNDERSTORMS ON THE STRONG SIDE...BUT WITH DEEPER LAYER SHEAR
AGAIN ON THE WEAKER SIDE...CHANCES FOR SEVERE WEATHER IS LOW.
AS FAR AS TEMPERATURES GO...WITH THE MORE EASTERLY COMPONENT TO
THE WINDS /ESP ACROSS SC NEB/ STILL EXPECTED...AGAIN MADE FEW
CHANGES. MID/UPPER 90S ARE IN PLACE ACROSS THE NORTH...WITH LOWER
100S POSSIBLE ACROSS NC KS. ENDED UP ISSUING A HEAT ADV FOR NC KS
THIS AFTERNOON...WHERE POTENTIAL FOR HEAT INDEX VALUES NEAR 105
LIES...WITH TEMPS NEAR/JUST ABOVE 100 POSSIBLE AND HIGHER
DEWPOINTS EXPECTED AS THAT AREA SITS NEAR/JUST NORTH OF THE SFC
FRONT. CERTAINLY NOT A SLAM DUNK ADVISORY...A COUPLE OF THINGS
COULD POTENTIALLY MESS UP THE FORECAST HIGHS IN NC KS...SUCH AS
EVEN HIGHER DEWPOINTS THAN CURRENTLY FORECAST /SOME DATA SHOWS
DPTS CLOSER TO THE MID TO UPPER 60S VS THE NEAR 60
FORECAST/...AND/OR HIGHER CLOUD COVER THAN WHAT IS CURRENTLY
FORECAST DURING THE PEAK OF THE AFTERNOON. DECIDED TO GO WITH THE
AREA THAT HAD THE BEST POTENTIAL TO MEET CRITERIA...ALSO THINKING
THE AFFECTS OF ANY THUNDERSTORM DEVELOPMENT WOULD HOLD OFF UNTIL
LATER IN THE AFTERNOON.
GETTING INTO MONDAY AND TUESDAY...AGAIN SEE LITTLE CHANGE IN THE
OVERALL UPPER LEVEL PATTERN...AND CONFIDENCE IN PRECIPITATION
CHANCES REMAINS ON THE LOW SIDE. THE CWA REMAINS UNDER THE
INFLUENCE OF THAT UPPER LEVEL RIDGE...BUT IT DOESNT EXTEND FAR
ENOUGH NORTH TO KEEP US OUT OF THE WAY OF ANY WEAK DISTURBANCE
MAKING THEIR WAY AROUND THE EDGE OF THE RIDGE. ALONG WITH THE
POTENTIAL FOR DISTURBANCES MOVING THROUGH...MODELS NOT IN TOO BAD
OF AGREEMENT SHOWING THIS LINGERING SURFACE BOUNDARY GENERALLY
NEAR/SOUTH OF THE NEB/KS STATE LINE. THOUGH THERE ARE POPS IN
PLACE THROUGH TUESDAY NIGHT...CERTAINLY DONT WANT TO GIVE OFF THE
IMPRESSION THAT THERE ARE GOOD/WIDESPREAD POSSIBILITIES THE ENTIRE
TIME. THE ISSUE IS THAT AT EVEN THIS POINT...JUST A DAY OR TWO
OUT...THERE IS STILL ENOUGH UNCERTAINTY WITH THE TIMING/PLACEMENT
OF THESE DISTURBANCES AND ASSOCIATED PRECIP CHANCES THAT NAILING
DOWN MORE SPECIFIC DETAILS...INCREASING OR REMOVING POPS FOR
PARTICULAR LOCATIONS...IS DIFFICULT...BUT AT LEAST THE CHANCES ARE
THERE. FORECAST HIGHS FOR MONDAY REMAIN GENERALLY IN THE LOWER/MID
90S...WITH TUESDAY IN THE MID/UPPER 90S.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
CONCERNS FOR THE TERM PERIOD AGAIN FOCUS ON THUNDERSTORM CHANCES
AND NUMEROUS SHORT WAVE PERTURBATIONS AROUND THE UPPER LEVEL
RIDGE. OTHERWISE NO CHANGES WERE MADE TO THE PREVIOUS FORECAST.
BEGINNING THE LONG TERM PERIOD...THE UPPER LEVEL RIDGE REMAINS
STATIONARY ACROSS PORTIONS OF TEXAS AND OKLAHOMA...FLANKED BY TWO
UPPER LEVEL TROUGHS ON EITHER COAST. THROUGHOUT THE PERIOD...THE
RIDGE SLOWLY BEGINS TO BREAK DOWN AS THE WESTERNMOST TROUGH
CONTINUES TO SHIFT EASTWARD ACROSS CANADA. AS SUCH...THE PEAK OF
THE RIDGE FLATTENS OUT ENOUGH THAT THE PLAINS REMAIN IN PERFECT
POSITION FOR ANY UPPER LEVEL SHORT WAVE THAT PASSES BY. ALTHOUGH
THERE REMAINS MANY DISCREPANCIES ON BOTH UPPER LEVEL FEATURES AND
SURFACE FEATURES AMONG THE LONG TERM MODELS...IT IS BECOMING MORE
AND MORE APPARENT AND SUGGESTED BY THE ALL BLEND MODELS THAT THERE
IS A POSSIBILITY OF AT LEAST SOME PRECIPITATION IN THE LONG TERM.
WHILE IT REMAINS QUITE TOUGH TO PINPOINT EXACTLY WHEN AND WHERE
THESE SHOWERS WILL OCCUR...WAS NOT CONFIDENT ENOUGH TO PULL ALL
POPS COMPLETELY OR LEAVE SLIGHT CHANCES IN EVERY PERIOD AS
SUGGESTED BY ALL BLENDS. PER NEIGHBOR COLLABORATION AND MODELS
INDICATIONS OF THE PRESENCE OF SHORT WAVES AND SURFACE BOUNDARIES
ACROSS THE REGION...CONTINUED WITH SLIGHT CHANCES BOTH WEDNESDAY
AFTERNOON...THURSDAY AND FRIDAY.
REGARDING TEMPERATURES IN THE LONG TERM...EXPECTING WARM
TEMPERATURES TO LAST THROUGH THE PERIOD...ALTHOUGH NOT QUITE HAS
HOT AS PREVIOUS WEEKS...CONTINUED WITH 90S TO NEAR 100 ACROSS
THE AREA. CLOUD COVER AND PRECIPITATION CHANCES COULD CERTAINLY
COME INTO QUESTION AND REDUCE HIGHS JUST SLIGHTLY. ALSO CONFIDENCE
REMAINS LOW FOR TEMPERATURES ON SATURDAY. THE GFS SOLUTION AND THE
ECWMF SOLUTION REMAIN COMPLETELY OPPOSITE EACH OTHER....WITH THE
GFS DRAGGING A COLD FRONT THROUGH THE REGION AND THE ECMWF
SUGGESTS A HIGH OVER THE AREA.
AVIATION...06Z KGRI TAF. AS SURFACE LOW PRESSURE CONTINUES TO
SPIN ACROSS WESTERN KANSAS...SURFACE HIGH PRESSURE WILL GRAZE
NORTHERN PORTIONS OF NEBRASKA TODAY. AS A RESULT...LIGHT AND
VARIABLE WINDS WILL GRADUALLY SHIFT TO THE NORTHEAST THIS MORNING
BEFORE TURNING EASTWARD BY THE END OF THE PERIOD. WHILE A FEW
SCATTERED TO EVEN BROKEN CLOUD DECK WILL APPEAR AT TIMES
THROUGHOUT THE PERIOD...EXPECTING VFR CONDITIONS TO CONTINUE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
FOR KSZ005>007-017>019.
&&
$$
SHORT...ADO
LONG/AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CDT SUN JUL 29 2012
.DISCUSSION...
THE LAST 3 RUNS OF THE HRRR INSIST ON RAPID DEVELOPMENT OF A
BOWING LINE STRUCTURE ALONG AND SOUTH OF THE I94 CORRIDOR THIS
MORNING...BUT CURRENT CONVECTIVE TRENDS DO NOT SUPPORT SUCH A
SCENARIO. SO...ONLY AESTHETIC CHANGES HAVE BEEN MADE TO THE
FORECAST THIS MORNING.
THE MAIN FORECAST PROBLEM TODAY WILL BE TIMING THE BARRAGE OF
MIDDLE LEVEL SHORTWAVES AIMED AT THE NORTHERN PLAINS...AND TRYING
TO DECIDE WHICH WILL PROVIDE SUFFICIENT BROAD SCALE LIFT TO RESULT
IN ORGANIZED SEVERE THUNDERSTORMS.
&&
.AVIATION...
SCT TO BKN MID LEVEL CLOUDS OVER TAF SITES. AREA OF LIGHT SHOWERS
AND VIRGA FROM NEAR KBIS MOVING EASTWARD MAY REACH KJMS BY AROUND 21-22Z.
SURFACE FRONTAL BOUNDARY TO BE ORIENTED FROM NEAR KDVL TO NEAR
KBIS/KDIK TO KHEI AROUND 18Z AND MAY BE THE FOCUS OF AFTERNOON TSTM
DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...SCHECK
AVIATION...JV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1025 AM EDT SUN JUL 29 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL CROSS THE AREA TODAY AND
MOVE TO THE EAST COAST MONDAY WHERE IT WILL BECOME NEARLY
STATIONARY. A WEAK COLD FRONT WILL SLOWLY CROSS THE AREA MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE OVER THE AREA TODAY. THE BIG QUESTION IS HOW MUCH
CUMULUS WILL DEVELOP. SOME PATCHY CLOUDS ACROSS THE REGION WILL
LIKELY EXPAND. THE DENSE FOG BURNED OFF QUICKLY OVER INLAND NW PA.
THE DAY WILL BE DRY EVEN THOUGH THE RUC MODEL AND THE HRRR IS
HINTING AT A FEW SHOWERS DEVELOPING. NO MAJOR CHANGES TO
TEMPERATURE FORECAST.
PREVIOUS DISCUSSION...
A FEW MID CLOUDS CONTINUE TO DEVELOP ACROSS EXTREME NE OH/NW PA
ON THE BACK EDGE OF THE UPPER TROUGH AND WILL PROBABLY DO SO
THROUGH MID MORNING. JUST COOL ENOUGH ALOFT FOR A FEW LAKE CLOUDS.
SCATTERED TO BROKEN CLOUDS HAVE BEEN MOST COMMON OFF THE WESTERN
BASIN THIS MORNING. THERE COULD ALSO BE SOME CLOUDS DEVELOP EARLY
THIS MORNING ALONG THE LAKESHORE DUE TO CONVERGENCE. A FEW OF
THESE LAKE CLOUDS WILL SPREAD INLAND THIS MORNING AND GRADUALLY
MIX AWAY AND TRANSITION TO A FEW FAIR WEATHER CUMULUS THIS
AFTERNOON. ALL THAT BEING SAID...WE SHOULD END UP WITH A NICE DAY
WITH PLENTY OF SUNSHINE AND RELATIVELY LOW HUMIDITY. HIGHS IN THE
LOWER/MID 80S EXCEPT A COUPLE OF DEGREES COOLER NEAR THE LAKE ERIE
LAKESHORE. ALSO MADE A FEW MINOR ADJUSTMENTS TO THE MORNING HOURLY
TEMPERATURES FOR THE EARLY MORNING UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
ANOTHER TROUGH ALOFT BEGINS TO DEVELOP OVER THE CENTRAL GREAT LAKES
AND OHIO VALLEY ON MONDAY. THE MODELS SEEM WAY TO AGGRESSIVE ON THE
CHANCE OF RAIN ON MONDAY. WHILE WE WILL GET CLOSER TO THE "RING OF
FIRE" JUST TO OUR WEST... IT SEEMS UNLIKELY GIVEN THE RELATIVELY
STABLE AND DRY AIR MASS AND THE NEARBY SURFACE HIGH PRESSURE THAT WE
WOULD SEE MUCH MORE THAN DEBRIS CLOUDS IN THE NORTHWEST FLOW ALOFT
AND A SHOWER OR SPRINKLE. A LOCAL SHOWER OR THUNDERSHOWER MIGHT POP
UP LATE IN THE DAY BUT AGAIN...THE COVERAGE SHOULD BE LIMITED. WILL
CONTINUE WITH A LOW PROBABILITY OF PRECIPITATION (20-30 PERCENT).
WILL TRIM BACK THE FORECAST TEMPERATURES A FEW DEGREES GIVEN THE
EXTRA CLOUDS AND THE WEAK WARM ADVECTION IN THE LIGHT FLOW.
THE NEXT COLD FRONT WILL APPROACH ON TUESDAY. THE LIGHT SOUTH FLOW
AHEAD OF THE FRONT WILL ENABLE THINGS TO BECOME MORE UNSTABLE. IT IS
NOT LIKE THE GULF WILL BE OPEN BUT DEWPOINTS WILL BEGIN TO RISE
THROUGH THE 60S AND IF WE SEE ENOUGH SUNSHINE THERE SHOULD BE A
SCATTERING OF THUNDERSTORMS. HIGHS WILL BE A FEW DEGREES WARMER
THAN MONDAY...IN THE MID/UPPER 80S.
I SUSPECT THE FRONT MAY BE LINGERING SOMEWHERE IN THE AREA ON
WEDNESDAY... ESPECIALLY NE OH/NW PA... GIVEN THE RISING HEIGHTS AND
LIGHT FLOW. KEPT A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS...
MAINLY ACROSS NE OH/NW PA. HIGHS WILL DEPEND ON WHERE THE FRONT ENDS
UP AND HOW MUCH CLOUDS/SHOWERS OCCUR. STAYED CLOSE TO THE PREVIOUS
FORECAST WITH HIGHS GENERALLY IN THE LOWER/MID 80S.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
MODELS IN REASONABLE AGREEMENT ON THURSDAY WITH HIGH PRESSURE OVER
THE GREAT LAKES. MODELS BEGIN TO DIVERGE FRIDAY WITH GFS MOVING LOW
PRESSURE SYSTEM INTO THE UPPER LAKES FRIDAY OPENING CHANCE POPS OVER
THE AREA FRIDAY INTO SUNDAY. ECMWF ON THE OTHER HAD MUCH SLOWER
MOVING HIGH PRESSURE OUT AND HOLDING LOW WELL WEST OF THE AREA INTO
SATURDAY. FOR THIS FORECAST LEANED TOWARD THE SLOWER ECMWF AND
HOLDING CHANCE OF PRECIP BACK UNTIL FRIDAY NIGHT AND INTO SATURDAY.
CONFIDENCE IS LOW THIS FAR OUT SO WILL GO WITH LOW CHANCE POPS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
CURRENTLY MVFR BR WITH PATCHY IFR VIS MAINLY SOUTH OF YNG-FDY
LINE. CONDITIONS SHOULD IMPROVE TO VFR BY MID MORNING...AND
CONTINUE THROUGH REMAINDER OF FORECAST PERIOD.
THE 850 MB TEMPS ARE DOWN TO 14C. DO EXPECT SOME LAKE EFFECT
CLOUDS TO DEVELOP THIS AFTERNOON...CONFIDENCE LOW AS TO HOW
WIDESPREAD IT WILL BE.
.OUTLOOK...NON VFR CONDITIONS ARE POSSIBLE TUESDAY IN SHOWERS AND
THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER MICHIGAN WILL SLIDE OVER THE LAKES TODAY
SO NORTH FLOW WILL BECOME MORE VARIABLE THIS AFTERNOON. HIGH SHIFTS
EAST OF THE LAKE ON MONDAY SETTING UP SOUTHERLY FLOW OVER THE LAKE.
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TUESDAY NIGHT INTO
WEDNESDAY MORNING. THIS WILL SET UP A WEST TO NORTHWEST FLOW OVER
THE LAKE. EXPECT CHOPPY CONDITIONS TO DEVELOP BUT FOR NOW LOOKS
LIKE WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KIELTYKA/KOSARIK
SHORT TERM...KOSARIK
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
643 AM CDT SUN JUL 29 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
306 AM CDT SUN JUL 29 2012
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE RAIN CHANCES
TODAY AND MONDAY.
A FEW DIFFERENT BANDS OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
ACROSS THE REGION AHEAD OF A 850-500MB TROUGH MOVING THROUGH
MINNESOTA. THIS LOW TO MID LEVEL FORCING WILL PROVIDE THE LIFT TO
KEEP CONVECTION GOING THROUGH THE MORNING HOURS TODAY BEFORE THE
TROUGH MAKES IT INTO EASTERN WISCONSIN THIS AFTERNOON. INSTABILITY
REMAINS RATHER WEAK NEAR THE NORTHERN BAND OF SHOWERS AT LESS
THAN 500 J/KG OF 0-3KM MUCAPE WHILE AN AXIS OF 500-1000 J/KG OF
MUCAPE IS NOSING UP INTO THE CONVECTION IN SOUTHWEST MINNESOTA AND
HAS LED TO SOME MORE LIGHTNING STRIKES THERE. THE BEST CHANCES
FOR ANY PRECIPITATION APPEAR TO BE ALONG AND WEST OF THE
MISSISSIPPI RIVER WITH THE CONVECTION DEVELOPING IN SOUTHWEST
MINNESOTA AHEAD OF THE TROUGH. THIS CONVECTION SHOULD BECOME MORE
WIDESPREAD THROUGH THE MORNING AND TRACK THROUGH SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. MEANWHILE...THE DEFORMATION BAND
ALONG A 800-600MB ZONE HAS SET UP FROM WEST CENTRAL MINNESOTA INTO
CENTRAL WISCONSIN. THE 29.02Z THROUGH 29.04Z HRRR HAS DONE A
FAIRLY GOOD JOB OF PICKING UP ON CURRENT TRENDS AND SHOWS THIS
BAND STICKING TOGETHER THOUGH DIMINISHING IN COVERAGE THROUGH THE
MORNING. BASED ON THIS...HAVE PULLED SOME OF THE HIGHER CHANCES TO
THE NORTHEAST INTO CENTRAL WISCONSIN THOUGH ANY RAINFALL AMOUNTS
SHOULD BE ON THE LOW SIDE. THIS PRECIPITATION LOOKS TO BE ON A
DIMINISHING TREND INTO THE AFTERNOON WITH MUCH OF THE REGION
CLEARING OUT BY THE EVENING AS A SURFACE RIDGE OF HIGH PRESSURE
EXTENDS WEST FROM THE GREAT LAKES INTO THE REGION.
WITH THIS RIDGE SITTING OVER THE REGION IN THE EVENING AND
OVERNIGHT HOURS...WINDS WILL GO CALM WITH SKIES CLEARING OUT.
WITH A FRESH RAINFALL POSSIBLE ACROSS MUCH OF THE REGION THIS
MORNING...EXPECT THAT THERE MAY BE SOME FOG THAT DEVELOPS
TONIGHT/TOMORROW MORNING. 29.00Z NAM/GFS FORECAST SOUNDINGS
SUPPORT THIS IDEA AS WELL WITH LIGHT WINDS LESS THAN 10KTS UP TO
AROUND 5KFT AND SURFACE DEW POINT DEPRESSIONS DOWN TO AROUND 1C BY
3Z TONIGHT. CONFIDENCE WAS NOT HIGH ENOUGH AT THIS POINT TO PUT A
WIDESPREAD MENTION IN THE FORECAST THOUGH HAVE PUT SOME IN ACROSS
THE VALLEY REGIONS.
THE FOCUS THEN GOES TO THE NEXT TROUGH THAT DIGS TO THE SOUTHEAST
ACROSS SOUTH CENTRAL CANADA INTO THE NORTHERN GREAT LAKES ON
MONDAY. THIS FEATURE PULLS A COLD FRONT DOWN ALONG WITH IT WITH
THE QUESTION BEING HOW FAR SOUTHWEST ALONG THE FRONT WILL
CONVECTION DEVELOP. THE LOW LEVEL MOISTURE TRANSPORT SOURCE FOR
THIS SYSTEM IS THE NORTHERN PLAINS WITH THE GULF CUT OFF BY THE
RIDGE TO THE SOUTH...WHICH MEANS THAT THERE IS NOT MUCH MOISTURE
AVAILABLE TO WORK WITH. THE TIMING ISSUES BETWEEN THE MODELS
APPEAR TO BECOMING LESS WITH THE TREND GOING TOWARD THE FASTER
NAM. ACCORDING TO THE 29.00Z NAM...THE MAIN LIFT IS IN THE LOW
LEVELS AHEAD OF THE COLD FRONT AHEAD OF WHEN THE MID LEVEL TROUGH
MOVES IN...SO THERE SHOULD NOT BE MUCH UPPER LEVEL INFLUENCE HERE.
INSTABILITY IS DECENT IN THE 1000-2000 J/KG RANGE WITH THE NAM/GFS
LIKELY OVER-FORECASTING THE SBCAPE DUE THEIR SURFACE DEW POINTS
BEING IN THE UPPER 60S TO LOW 70S WHEN WE WILL MORE LIKELY BE IN
THE MID 60S. 29.00Z NAM FORECAST SOUNDINGS WOULD ALSO SUGGEST THAT
THE ATMOSPHERE IS CAPPED FROM AN INVERSION AROUND 750MB THAT WOULD
STRENGTHEN WITH LOWER SFC DEW POINTS. BASED ON THIS...HAVE FOCUSED
THE BETTER CHANCES TO CENTRAL WISCONSIN WHERE THE COMBINATION OF
FORCING AND LESS OF A CAP MAY LEAD TO SOME CONVECTION BUT HAVE
LEFT SOME SLIGHT CHANCES IN TO THE SOUTHWEST ALONG THE FRONT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
306 AM CDT SUN JUL 29 2012
NOT MUCH CONFIDENCE IN THE LATER PART OF THE WEEK WITH THE UPPER
LEVEL FLOW EXPECTED TO BECOME MORE ZONAL TOWARD NEXT WEEKEND.
SURFACE HIGH PRESSURE WILL BE IN PLACE WEDNESDAY BEFORE A COLD
FRONT DROPS DOWN INTO THE REGION WEDNESDAY NIGHT AND THURSDAY.
THIS FRONT THEN APPEARS TO STALL OUT ACROSS THE REGION WHICH KEEPS
PRECIPITATION CHANCES AROUND THROUGH THE REST OF THE WEEK. SOME
TIMING DIFFERENCES WITH THE FRONT VIA THE 29.00Z GFS/ECMWF LEADS
TO HAVING THE CHANCES THROUGH THE WEEK THOUGH THERE WILL LIKELY BE
SOME BREAKS AT TIMES. TEMPERATURE-WISE IT STILL LOOKS FAIRLY
SEASONAL WITH NOT MUCH IN THE WAY OF CHANGES DUE TO WEAK LOW LEVEL
WARM AIR ADVECTION.
&&
.AVIATION...TODAY AND TONIGHT
642 AM CDT SUN JUL 29 2012
A SHORT WAVE TROUGH WILL MOVE SOUTHEAST THROUGH THE AREA THIS
MORNING. THIS SYSTEM WILL BRING WITH IT SHOWERS AND ISOLATED
THUNDERSTORMS TO THE AREA. WITH THE BEST INSTABILITY SOUTH OF THE
TAF SITES... DID NOT INCLUDE ANY THUNDERSTORMS IN THE TAFS.
CEILINGS WILL BE MAINLY VFR. HOWEVER THERE ARE A FEW PATCHES OF
BROKEN IFR AT THE SHOWERS ONSET. THE VISIBILITIES WILL BE MAINLY
VFR. HOWEVER IT MAY BRIEFLY BECOME MVFR IN THE HEAVIER SHOWERS.
STRONG SUBSIDENCE WILL MOVE INTO THE AREA IN THE WAKE OF THIS
SYSTEM. THIS SHOULD RESULT IN CLEARING SKIES FOR THIS AFTERNOON.
THE LAMP GUIDANCE DEVELOPS DENSE FOG AT BOTH TAF SITES FOR MONDAY
MORNING. WITH DRY SOILS AND SOME CLEARING THIS AFTERNOON...NOT
CONVINCED THAT THIS WILL HAPPEN...SO DID NOT INCLUDE IT IN THE TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CDT SUN JUL 29 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
355 PM MDT SUN JUL 29 2012
.SHORT TERM...
(TONIGHT AND MONDAY)
WATER VAPOR LOOPS TODAY CONTINUE TO SHOW DRY AIR PUNCHING IN UNDER
THE RIDGE ACROSS NM/SRN CO. LATEST AMSU SSM/I PRECIP WATER SAT PICS
ALSO SHOWING VALUES DROPPING OFF TO THE SOUTH...BUT STILL AN AXIS OF
HIGH PRECIP WATERS EXTENDING ACROSS NW CO. A COUPLE SHORTWAVES
EVIDENT IN WV PICS ACROSS UT/NW CO. MAIN FORCING FROM THESE MAY END
UP STAYING JUST TO THE NORTH OF THE FORECAST...BUT STILL ENOUGH
MOISTURE PRESENT WITHIN MONSOON PLUME ALOFT FOR SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS. GREATEST
COVERAGE WILL BE ACROSS CHAFFEE AND LAKE COUNTIES...AND POSSIBLY
TELLER...THOUGH EACH SUCCESSIVE HRRR RUN SEEMS TO SHIFT
AXIS OF HIGHER QPF TO THE NORTH ACROSS PARK COUNTY. WITH PRECIP
WATERS STILL AVERAGING AROUND OR SLIGHTLY BETTER THAN 100 PERCENT OF
NORMAL ACROSS THE SOUTHEAST MTS/ADJACENT PLAINS...LOCALLY HEAVY RAIN
WILL STILL BE A THREAT...PARTICULARLY FOR THE WALDO CANYON BURN SCAR
WHERE SOILS ARE SUSCEPTIBLE TO FLASH FLOODING WITH EVEN MINOR
AMOUNTS OF RAINFALL...ESPECIALLY WITH THE LIGHT RAIN THAT FELL
ACROSS THE REGION YESTERDAY. THE LOOSE SOILS OF THE CHALK CLIFFS IN
CHAFFEE COUNTY WOULD BE PRONE TO FLASH FLOODING TODAY AS WELL.
CONVECTION WHICH FIRES OFF TO THE NORTH AND MOVES ACROSS THE NE
PLAINS WILL SEND AN INITIAL CONVECTIVE OUTFLOW BOUNDARY THROUGH THE
NRN I-25 CORRIDOR...WITH A WIND SHIFT FROM THE WEST TO NORTHWEST
DURING THE EVENING PRIOR TO THE MAIN FRONT DROPPING SOUTHWARD
THROUGH THE PLAINS AFTER 03Z. LATEST NAM12 ADVECTS SOME LOWER 50S
DEW POINTS BEHIND THE FRONT INTO SE CO BY MON MORNING...THEN SHIFTS
WINDS WEAKLY FROM THE EAST AND MIXES OUT LOW LEVEL MOISTURE AGAIN BY
AFTERNOON...WITH DEW POINTS FALLING OFF INTO THE LOWER TO MID 40S BY
21Z. DRY AIR ALOFT WILL STILL BE LINGERING OVER SOUTHERN
AREAS...WITH MONSOON PLUME WITH ITS WEAK EMBEDDED IMPULSES EXTENDING
ACROSS UT THROUGH NRN AND CENTRAL CO. THUS GREATEST THREAT FOR
WIDESPREAD THUNDERSTORMS/HEAVY RAIN WILL BE ACROSS NORTHERN PORTIONS
OF THE FORECAST AREA. QUITE A BIT OF DISCREPANCIES IN THE MODEL
QPFS BETWEEN THE DRIER NAM AND THE WET GFS. GFS KEEPS DEW POINTS
ACROSS THE SE PLAINS IN THE 50S THROUGH THE AFTERNOON WITH STRONGER
EASTERLY UPSLOPE FLOW...RESULTING IN GREATER QPF FOR THE SE MTS.
ECMWF SIDES WITH THE DRIER NAM12...AND SREF IS SOMEWHERE IN
BETWEEN...THOUGH ITS QPF IS GENERALLY UNDER .25 ON AN AREAL AVERAGE
BASIS. LCLS STILL LOOK A LITTLE TOO HIGH TO JUSTIFY A FLASH FLOOD
WATCH AT THIS POINT...SO PLAN TO HOLD OFF. LATER SHIFTS CAN GET A
LOOK AT THE HIGH RES MODEL RUNS TONIGHT AND DECIDE IF ONE IS
JUSTIFIED. A LOT WILL DEPEND ON HOW FAR NORTH THE DRY AIR ALOFT
PROGRESSES OVERNIGHT. HOWEVER...THERE COULD BE A HEIGHTENED CONCERN
FOR FLASH FLOODING ON THE WALDO BURN SCAR TOMORROW VS THE PAST FEW
DAYS...AS SFC DEW POINTS SHOULD REMAIN A LITTLE HIGHER.
OTHERWISE...TEMPERATURES SHOULD BE SLIGHTLY COOLER ACROSS THE PLAINS
BEHIND THE FRONT...THOUGH STILL APPROACHING 100 NEAR THE CO/KS
BORDER. MTN AREAS WILL SEE HIGHS SIMILAR TO A COUPLE DEGREES
WARMER. -KT
.LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
LONGER TERM METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES AND
POPS. 12Z/28TH GFS40 INDICATES THAT UPPER HIGH CENTERED OVER
NORTHEASTERN NEW MEXICO AT 00Z TUESDAY HOVERS OVER NEW MEXICO INTO
NEXT WEEKEND WHILE THE 12Z/28TH ECMWF SUGGESTS THAT HEALTHY UPPER
HIGH LOCATED OVER NORTHEASTERN NEW MEXICO AT 00Z TUESDAY SHIFTS
INTO NORTH TEXAS BY 06Z SATURDAY. IN ADDITION...THE 06Z/28TH DGEX
SUGGESTS THAT THE UPPER HIGH WILL BE OVER MISSOURI BY NEXT SUNDAY.
AT THE SURFACE...NORTHERLY SURGES IMPACTING PRIMARILY EASTERN
PORTIONS OF THE FORECAST DISTRICT ARE ANTICIPATED THURSDAY
MORNING...WITH A STRONGER NORTHERLY SURGE EXPECTED SATURDAY
MORNING.
THE COMBINATION OF RELATIVELY PERSISTENT DEEPER ATMOSPHERIC
MOISTURE/HIGHER PRECIPITABLE WATER VALUES IN COMBINATION WITH
THE DAILY HEATING CYCLE...THE AFORE-MENTIONED NORTHERLY SURGES
AND INCREASING UPPER ENERGY(ESPECIALLY AFTER TUESDAY) WILL ALLOW
ISOLATED TO SCATTERED PRIMARILY AFTERNOON AND EVENING
THUNDERSTORMS(SOME CONTAINING LOCALLY HEAVY RAIN AND HAIL) TO BE
NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT INTO NEXT
WEEKEND.
BLEND OF LATEST COMPUTER SIMULATIONS SUGGEST THAT INCREASING
PROBABILITIES OF THUNDERSTORMS WILL BE POSSIBLE OVER PORTIONS OF
THE I-25 CORRIDOR/EASTERN COLORADO PLAINS AS THE WEEK PROGRESSES
AND INTO NEXT WEEKEND.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND FLASH
FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS THE
WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
MAXIMUM AND MINIMUM TEMPERATURES FROM TUESDAY NIGHT INTO NEXT
SUNDAY ARE STILL EXPECTED TO RUN A CATEGORY OR TWO ABOVE LATE
JULY/EARLY AUGUST CLIMATOLOGICAL AVERAGES.
&&
.AVIATION...
VCTS WILL BE POSSIBLE AT TAF SITES THROUGH 02-03Z. GUSTY ERRATIC
WINDS UP TO 35 KTS WILL BE POSSIBLE NEAR -TSRA POSSIBLY AFFECTING
THE KCOS AND KPUB SITES. VFR CIGS/VIS IN LIGHT RAIN WILL ALSO BE
POSSIBLE SHOULD STORMS BE LUCKY ENOUGH TO HIT THE TERMINAL. AT THIS
POINT THREAT LOOKS FAIRLY LOW...AND WILL MAINTAIN VCTS. CONVECTION
OVER THE MOUNTAINS SHOULD SHIFT WINDS FROM THE NORTH TO NORTHWEST AT
BOTH KCOS AND KPUB AROUND 00Z WITH GUSTS IN THE 15-25 KT RANGE.
FRONT WILL DROP THROUGH THE PLAINS AFTER 03Z...WHICH SHOULD KEEP
WINDS FROM THE NORTH AT AROUND 10-15 KTS FOR BOTH KCOS AND KPUB
THROUGH 09Z. MEANWHILE...THUNDERSTORM COVERAGE SHOULD DECREASE
AFTER SUNSET...THOUGH ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE
OVER AND NEAR THE MOUNTAINS THROUGH AT LEAST 06Z. ON MONDAY...WINDS
WILL SWING AROUND FROM THE EAST TO SOUTHEAST ACROSS THE PLAINS
DURING THE AFTERNOON WITH A SLIGHTLY BETTER CHANCE FOR -TSRA AT THE
KCOS TAF SITE DURING THE AFTERNOON. WINDS WILL REMAIN LIGHT AT KALS.
-KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER CO
1059 AM MDT SUN JUL 29 2012
.UPDATE...PRECIPIATBLE WATER VAPOR TRENDS FROM GPS SHOW A 24 HOUR
INCREASE OF 0.05 TO 0.10 INCH OVER EASTERN COLORADO WITH AN
INCREASE OF 0.10 TO 0.20 OVER WESTERN COLORADO WHERE DEEPEST
MONSOONAL MOISTURE PLUME IS LOCATED. IN ADDITION...THERE SHOULD BE
SOME WEAK Q-G VERTICAL MOTION MOVING ACROSS THE FORECAST AREA THIS
AFTERNOON AND EVENING AS RIGHT ENTRANCE REGION OF UPPER JET MOVES
ACROSS WYOMING/NORTHERN UTAH. LATEST HRRR AND RAP SHOW CONVECTION
QUICKLY DEVELOPING IN THE MOUNTAINS AND FOOTHILLS BY NOON AND THEN
SPREADING ONTO THE PLAINS AFTER 2 PM WITH DECENT COVERAGE...SO
HAVE INCREASED POPS A BIT MORE FOR THE AFTERNOON HOURS IN/NEAR THE
FRONT RANGE. THREAT OF LOCALLY HEAVY RAIN IS STILL THERE WITH
HIGHER PW VALUES...ENOUGH TO KEEP SOME FLOODING POTENTIAL IN THE
BURN SCARS ESPECIALLY IF CELLS BEGIN TO TRAIN. OTHERWISE STORM
MOTION SHOULD BE FAST ENOUGH AROUND 15 MPH TO MINIMIZE RISK OF
FLOODING IN OTHER LOCATIONS. RAIN RATES OF AT LEAST 1 INCH IN 30
MINUTES POSSIBLE.
&&
.AVIATION...CURRENT AVIATION FORECAST ON TRACK WITH HIGHER STORM
COVERAGE EXPECTED TODAY WHICH WARRANTS A TEMPO TS GROUP IN THE
TAFS THIS AFTERNOON. HIGHEST PROBABILITY FOR THUNDER WILL BE 21Z-
01Z FOR THE FRONT RANGE AIRPORTS. STORM COVERAGE HIGH ENOUGH TO
POSSIBLY SHUT OFF APPROACH GATES...WESTERN GATES 18Z-02Z AND
EASTERN GATES 22Z-03Z.
&&
.PREV DISCUSSION... /ISSUED 351 AM MDT SUN JUL 29 2012/
SHORT TERM...THERE HAS BEEN SOME SLIGHT WESTWARD PROGRESSION OF THE
UPPER HIGH WHICH HAS RESULTED IN A WESTWARD SHIFT OF THE MOISTURE
PLUME AS WELL. RESULT LOOKS TO BE AN A WEAK EASTERLY WAVE PUSHING
INTO EASTERN ARIZONA WHICH WILL SHIFT INTO NORTHERN COLORADO THIS
AFTERNOON AND EVENING. ALREADY THERE IS QUITE A BIT OF SHOWER
ACTIVITY OVER WESTERN PORTIONS OF COLORADO AHEAD OF THIS FEATURE.
INTEGRATED PW VALUES FROM GPS SHOW A SLIGHT INCREASE IN PW OVER THE
FRONT RANGE OVER THE PAST 24 HOURS WITH EVEN A GREATER INCREASE AT
GJT...AROUND 1.38" AS OF 09Z. PROFILER DATA CONTINUES TO SHOW A
SOUTHWEST FLOW ALOFT OF 20-30KT. OVERALL...LOOKS TO BE AN UPSWING IN
STORMS TODAY ESPECIALLY OVER THE NORTHEAST PLAINS GIVEN THE HIGHER
MOISTURE LEVELS AND MORE INSTABILITY THEN WE SAW YESTERDAY. CURRENT
FORECASTS LOOK IN GOOD SHAPE SHOWING LIKELY POPS IN THE MOUNTAINS
AND CHANCE POPS OVER THE PLAINS. MODEL GUIDANCE CONCURS AND SHOWING
GENERALLY 30-40 POPS OVER MANY LOCATIONS. PW VALUES EXPECTED TO
CLIMB WELL OVER AN INCH BY THIS AFTERNOON. TEMPERATURES WILL BE
SIMILAR TO FRIDAY OR A FEW DEGREES COOLER DUE TO MORE CLOUD COVER AN
EARLIER DEVELOPMENT OF STORMS THIS AFTERNOON.
LONG TERM...MOISTURE LADEN SUBTROPICAL AIR WILL CONTINUE TO
STREAM NORTHWARD OUT OF NORTHWEST MEXICO AND THE U.S. DESERT
SOUTHWEST AROUND THE OUTER EDGE OF A STRONG SUBTROPICAL HIGH
PRESSURE RIDGE MEANDERING OVER TEXAS...OKLAHOMA AND NEW MEXICO
THROUGH THE MIDDLE OF THE WEEK. 850-500MB MEAN SPECIFIC HUMIDITY
VALUES OVER THE FORECAST AREA PEAK LATE ON MONDAY AROUND 8.5
G/KG...WHICH COINCIDES WITH MEAN LAYER PRECIPITABLE WATER VALUES
AROUND 0.8 INCH OVER THE FRONT RANGE AND NEAR 1.5 INCHES IN FAR
NORTHEASTERN COLORADO. HOWEVER THESE VALUES ARE DOWN FROM READINGS
PROGGED THE DAY BEFORE AS THIS PLUME OF MONSOONAL MOISTURE SHOWS
SIGNS OF CUTTING OFF FROM ITS SOURCE REGION IN NWRN MEXICO WITH
THE UPPER RIDGE NOSING WESTWARD ACROSS NEW MEXICO. STEEP 700-500MB
LAPSE RATES AND POCKETS OF SFC BASED CAPE IN THE 500-1000 J/KG
RANGE MONDAY AFTERNOON OVER AND ALONG THE FRONT RANGE SHOULD
ALLOW SCATTERED T-STORMS TO DEVELOP IN THESE AREAS. FARTHER OUT
ACROSS THE PLAINS...MODELS DIFFER ON THE AMOUNT OF CAPE/
INSTABILITY OUT THAT WAY. THE NAM BARELY INDICATES 500 J/KG OF
CAPE BY 00Z/TUE...WHILE THE GFS INDICATES A WIDE NORTH-SOUTH BAND
OF 1600-2200 J/KG OF CAPE...NO DOUBT IN RESPONSE TO THE MODEL/S
HIGHER PW AND DEWPT VALUES OUT THERE. THE EUROPEAN MODEL FITS
NICELY BETWEEN THE TWO MODELS. WILL GO WITH A BLEND OF THE MODELS
BUT LEAN A BIT MORE ON THE DRIER NAM. HIGHER POPS OVER AND NEAR
THE HIGH TERRAIN WILL TAPER DOWN ACROSS THE PLAINS EVEN WITH ALL
OF THE SFC BASED CAPE OUT THERE AS PER THE GFS. TRANSPORT WINDS
ON MONDAY BECOME MORE WESTERLY AND SLIGHTLY GREATER IN SPEED...SO
THE THREAT OF FLASH FLOODING APPEARS LOW. OF COURSE IT DOESN/T TAKE
MUCH RAIN TO CAUSE FLASH FLOOD...DEBRIS FLOWS...ROCK SLIDES AND
THE LIKE ON THE SLOPED TERRAIN RECENTLY SCORCHED BY WILDFIRE.
AFTER MONDAY...STORM CHANCES GRADUALLY DECREASE WITH AVAILABLE
PRECIPITABLE WATER ON THE DECREASE. FEWER CLOUDS SHOULD RESULT IN
SLIGHTLY WARMER TEMPERATURES EACH DAY. BY THURSDAY THE UPPER RIDGE
CENTERED OVER NEW MEXICO FLATTENS OUT RESULTING IN WESTERLY FLOW
ALOFT OVER NORTH CENTRAL AND NORTHEAST COLORADO. WEST-NORTHWEST
BNDRY LAYER FLOW AIDS IN THE DRYING ALREADY UNDERWAY EAST OF THE
MTNS. THIS DOWNSLOPE FLOW COULD PUSH AFTERNOON TEMPERATURES NEAR
THE CENTURY MARK ON THE PLAINS..MAKING THURSDAY THE WARMEST DAY OF
THE WEEK. WARMING AND DRYING ALOFT SHOULD PRETTY PREVENT ANY STORM
FORMATION EAST OF THE FRONT RANGE. WHAT STORMS THAT MANAGE TO FORM
IN THE HIGH COUNTRY WILL BE FEW AND FAR BETWEEN. BY FRIDAY INTO
SATURDAY...MEDIUM RANGE MODELS HINT AT A MODEST INFLUX OF
SUBTROPICAL MOISTURE MAINLY;Y OVER SOUTHERN SECTIONS OF THE
FORECAST AREA. AS A RESULT COULD SEE A MODEST INCREASE IN T-STORM
COVERAGE AND SLIGHTLY COOLER TEMPERATURES.
AVIATION...LITTLE CHANGE PLANNED TO 12Z TAF ISSUANCE FOR LOCAL
TERMINALS. INCREASE CHANCES OF STORMS TODAY AND ALREADY COVERED WITH
TEMPO GROUPS STARTING AROUND MID AFTERNOON THRU EARLY EVENING. WIND
FIELDS FAIRLY LIGHT TODAY UNTIL STORMS FIRE WITH EXPECTED OUTFLOW
GUSTY AND VARIABLE WINDS.
HYDROLOGY...FLASH FLOOD THREAT A BIT HIGHER TODAY WITH HIGHER
MOISTURE VALUES AS PW VALUES WILL BE WELL ABOVE AN INCH IN THE
FOOTHILLS. RAINFALL RATES AS HIGH AS ONE INCH IN 30 MINUTES
POSSIBLE WITH THE STRONGER STORMS. BURN SCARS NEED TO BE ON ALERT
WITH LOCALIZED FLOODING POSSIBLE. STORMS STILL SHOULD BE MOVING FAIRLY
DECENT AT 10-15 KT UNLESS STORM TRAINING OCCURS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
138 PM EDT SUN JUL 29 2012
.PREV DISCUSSION...
UPDATE...
/ISSUED 1052 AM EDT SUN JUL 29 2012/
MSAS DEW POINT AND PRESSURE ANALYSIS INDICATES THE FRONT IS
SITUATED ACROSS CENTRAL GEORGIA...BETWEEN ATL AND THE CSG TO MCN
AREA. FORECAST THINKING IS STILL ON TRACK WITH BEST PRECIP CHANCES
ALONG AND SOUTH OF THE FRONT SO NO CHANGES TO THE AFTERNOON POPS.
FORECAST IS OVERALL IN LINE WITH THE 11Z HRRR RUN SHOWING ISOLATED
DEVELOPMENT ACROSS NORTH GEORGIA WITH HIGHER COVERAGE ACROSS THE
SOUTHERN THIRD OF THE FORECAST AREA.
ONLY TWEAKS TO THE FORECAST ARE BASED ON CURRENT TEMP...DEW POINT
AND RADAR TRENDS. CUT DOWN ON POPS ACROSS CENTRAL GEORGIA FOR THE
REST OF THE MORNING AS THE AREA OF SHOWERS THAT PERSISTED THROUGH
MUCH OF THE MORNING HAS DISSIPATED.
11
SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
LATEST SURFACE ANALYSIS SHOWS SURFACE FRONT HAS MADE ITS WAY INTO
THE ATLANTA METRO AREA WITH LOW END SCATTERED COVERAGE OF SHOWERS
AND VERY ISOLATED THUNDERSTORMS MARKING ITS LEADING EDGE. HAVE
MADE SOME MINOR INITIAL GRID MODIFICATIONS TO TAKE POPS THROUGH
12Z. OTHERWISE...AREA IS UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES
WITH INITIALIZED UPPER LEVELS SHOWING CONTINUED TROUGH DEVELOPMENT
IN THE TENNESSEE VALLEY AND INTO THE LOCAL AREA.
FOR THE REMAINDER OF TODAY...ANTICIPATE MAIN DEVELOPMENT TO BE
ALONG THE MAIN FRONT AND ENHANCED POPS EXPECTED WITH AFTERNOON
HEATING. THIS WILL GENERALLY OCCUR OVER SOUTHERN SECTIONS OF THE
FORECAST AREA AND WILL FOCUS HIGHEST GRIDDED POPS THERE. CONTINUE
TO WATCH AREA ALONG THE FRONT OF ENHANCED DOWNDRAFT CAPE WITH
CLOSE TO 1000 J/KG ACCOUNTING FOR NUMEROUS OUTFLOWS SEEN ON RADAR
DESPITE SHALLOW CORES. ANTICIPATING THIS AREA TO SHIFT SOUTH WITH
SOME THREAT OF AN ISOLATED SEVERE WIND GUST IN STRONGEST ACTIVITY
THIS AFTERNOON.
EXPECTING SOME DRY AIR TO MIX DOWN THIS AFTERNOON BUT WITH TEMPS
LIKELY SLIGHTLY ABOVE GUIDANCE AGAIN...WILL SEE SOME ISOLATED HEAT
INDICES ABOVE 105. LIKE YESTERDAY...NOT EXPECTING WIDESPREAD
ENOUGH CONDITIONS TO WARRANT ADVISORY.
FOR MONDAY...STILL A GOOD DEAL OF DRY AIR IN PLACE AT THE MID
LEVELS TO INHIBIT CONVECTION INITIALLY. HOWEVER...A LATE ARRIVING
SHORTWAVE LOOKS TO PROVIDE TO FOCUS FOR ENHANCED ACTIVITY AND WILL
GO ABOVE GUIDANCE FOR POPS WITH LOW END CHANCE.
DEESE
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
DISSIPATING STATIONARY FRONT OR SURFACE TROUGH ACROSS THE AREA TO
START THE LONG TERM WITH AN UPPER TROUGH ALONG THE EASTERN SEABOARD.
MODELS INDICATING THE POTENTIAL FOR SHORT WAVES IN THE NW FLOW ALOFT
TO AFFECT THE AREA MONDAY NIGHT AND TUESDAY ALLOWING FOR THE CHANCE
OF SHOWERS AND THUNDERSTORMS. THIS POTENTIAL FOR SHORT WAVES TO
AFFECT THE FORECAST AREA LOOKS TO CONTINUE WEDNESDAY AND THURSDAY.
ON FRIDAY THE UPPER RIDGE BEGINS TO BUILD AND LOOKS TO CONTINUE OVER
THE AREA THE REST OF THE LONG TERM. THIS SHOULD DIMINISH SOME THE
OVERALL POTENTIAL FOR SHOWERS AND THUNDERSTORMS WITH A HIGHLY
DIURNAL NATURE TO ANY CONVECTION.
HIGH TEMPERATURES SHOULD MODERATE SOME FOR THE FIRST PART OF THE
LONG TERM WITH HIGHS IN THE LOWER HALF OF THE 90S ON THE HIGH SIDE
AND THEN WARM TO THE UPPER HALF OF THE 90S TO NEAR 100 AT WEEKS END.
BDL
&&
.AVIATION...
18Z UPDATE...
FRONT REMAINS JUST SOUTH OF THE ATL TO AHN AREA AND BEST CHANCE OF
CONVECTION WILL REMAIN ALONG AND SOUTH OF THIS FRONT. THIS MEANS
THE BEST CHANCE OF TSRA WILL BE AT MCN AND CSG THIS AFTERNOON.
THERE IS A SLIGHT CHANCE AT THE REMAINDER OF THE SITES...BUT NOT
HIGH ENOUGH TO MENTION IN THE TAF. HAVE STARTED TO SEE SOME GUSTS
ACROSS ATL SITES AND THESE WILL LAST INTO AT LEAST THE FIRST HALF
OF THE AFTERNOON.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON WIND...CIGS AND VSBY. MEDIUM CONFIDENCE ON
TSRA NOT OCCURRING AT ATL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 97 70 96 72 / 20 20 30 20
ATLANTA 96 73 94 75 / 20 20 30 20
BLAIRSVILLE 89 63 89 66 / 20 20 20 40
CARTERSVILLE 93 64 95 70 / 20 20 30 40
COLUMBUS 97 74 97 75 / 40 30 30 20
GAINESVILLE 93 71 92 72 / 20 20 30 30
MACON 97 72 96 73 / 40 30 30 20
ROME 94 64 95 70 / 20 20 30 40
PEACHTREE CITY 94 67 95 70 / 20 20 30 20
VIDALIA 93 75 96 75 / 40 40 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...11
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1258 PM CDT SUN JUL 29 2012
.DISCUSSION...
ISSUED 1045 AM CDT SUN JUL 29 2012
FORECAST LOOKS FAIRLY GOOD TODAY AND JUST A FEW ADJUSTMENTS NEEDED
LIKE INCREASING CLOUD COVER A BIT MORE SIMILAR TO YESTERDAY WITH
PARTLY TO MOSTLY CLOUDY SKIES OVERALL. HIGHS IN THE MID TO UPPER 80S
WITH LOWER 90S OVER SW AREAS. CONTINUED 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON WHILE KEEPING AREAS EAST OF I-57
DRY. NAM AND HRRR MODELS IN BETTER AGREEMENT WITH SOME QPF OVER
WESTERN AREAS THIS AFTERNOON AND THIS IS SUPPORTED BY CURRENT FORECAST.
MOST SHOWERS AND ISOLATED THUNDERSTORMS STAYED SW OF CENTRAL IL
THIS MORNING OVER SW IL INTO EASTERN MO AND DRIFTING SE INTO THE
MID MS VALLEY. WEAK LOW PRESSURE 1013 MB NEAR THE IA/NE BORDER TO
TRACK SE TOWARD ST LOUIS BY 12Z/MON AND TO REDEVELOP ISOLATED TO
SCATTERED CONVECTION THIS AFTERNOON AND INTO TONIGHT OVER WESTERN
AREAS. SPC HAS 5% RISK OF SEVERE STORMS OVER WESTERN AREAS LATER
THIS AFTERNOON AND EVENING.
KH
&&
.AVIATION...
ISSUED 1255 PM CDT SUN JUL 29 2012
TRICKY FORECAST WITH CONVECTION CHANCES NEXT 24 HOURS BUT BEST
CHANCES APPEAR IN MORE UNSTABLE AIR MASS IN SW/WEST CENTRAL IL AT
SPI FROM MID AFTERNOON UNTIL SUNSET AND MAINTAINED VCTS THERE.
ALSO HAVE BULK SHEAR OF 40 KTS IN THIS AREA WHERE SPC NOW HAS A
SLIGHT RISK OF SEVERE STORMS FROM MID AFTEROON UNTIL SUNSET WEST
OF A GALESBURG TO CANTON TO SPRINGFIELD LINE. ALSO KEPT VCSH AT
DEC FROM 22Z-02Z. GENERALLY KEPT VFR CONDITIONS GOING ACROSS THE
CENTRAL IL TAF SITES WITH CEILINGS 4-6K FT POSSIBLE AT TIMES. IF A
THUNDERSTORM DOES OCCUR...VSBY COULD BRIEFLY GET MVFR OR LOWER. WEAK
LOW PRESSURE 1012 MB NEAR THE IA/NE BORDER AND NE KS HAS WARM
FRONT EXTENDING THROUGH CENTRAL IA/IL SOUTH OF I-74 AS SE WINDS
TURN SOUTH IN WARM SECTOR. MODELS TAKE WEAK LOW PRESSURE SE INTO
SE MO/SW IL BY 18Z/MON. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP DURING THIS AFTERNOON AND INTO THIS
EVENING OVER MAINLY WESTERN/SW AREAS CLOSER TO LOW PRESSURE
SYSTEM. ALSO HAVE AREA OF SHOWERS OVER SW WI...NW IL AND FAR NE
IOWA THAT IS MOVING ESE AND COULD GET CLOSE TO CMI DURING TONIGHT.
SSE WINDS 8-13 KTS THIS AFTERNOON TO BE SE 6-8 KTS TONIGHT AND SE
AROUND 10 KTS MON MORNING.
KH
&&
.PREV DISCUSSION...
ISSUED 254 AM CDT SUN JUL 29 2012
AT 06Z HIGH PRESSURE STILL OCCUPIED THE GREAT LAKES AND THIS
PROVIDED A CALM AND SEASONABLE NIGHT ACROSS CENTRAL IL. FARTHER
WEST POORLY ORGANIZED BROAD LOW PRESSURE STRETCHED ACROSS THE
CENTRAL PLAINS. ALOFT...NORTHWEST FLOW DOMINATED MUCH OF THE
MIDWEST. CONVECTION AS CLOSE AS SE IA/NE MO WAS OCCURRING AHEAD OF
A SHORTWAVE DROPPING INTO SW MN...AND ALONG A MID LEVEL THETA-E
GRADIENT AND AREA OF 850MB MOISTURE CONVERGENCE. AS THIS AREA OF
LIFT AND CONVERGENCE SHIFTS SOUTHEAST TODAY THUNDERSTORM CHANCES
WILL RETURN TO THE FORECAST.
SHORT TERM...TODAY THROUGH MONDAY
EXPECT SCATTERED CONVECTION TO PUSH INTO THE WESTERN CWA AFTER SUNRISE
AND GRADUALLY DIMINISH THROUGH THE MORNING AS MID LEVEL CONVERGENCE
WANES. THEREFORE HAVE HIGHEST POPS IN THE FAR WEST QUICKLY
TAPERING TO SLIGHT CHANCE FOR THE CENTRAL AND EASTERN CWA. LIFT
AHEAD OF THE SHORTWAVE DROPPING IN FROM THE NORTHWEST COULD KEEP
ISOLATED TO SCATTERED CONVECTION GOING INTO THE AFTERNOON BUT DO
NOT ANTICIPATE HIGH COVERAGE. WHILE INSTABILITY IS LIMITED /MUCAPES
700-900 J/KG/...SHEAR IS MORE IMPRESSIVE DUE TO SOUTHERLY SURFACE
WINDS AND WESTERLY FLOW ALOFT WHICH CONTRIBUTES TO 40 KTS OF BULK
SHEAR. SO SOME THUNDERSTORM ORGANIZATION IS POSSIBLE WITH STRONGER
CELLS CAPABLE OF SMALL HAIL OR BRIEF GUSTY WINDS...MOST FAVORED IN
THE SOUTHWEST CWA. WITH THE LIKELIHOOD OF INCREASED CLOUD COVER
WILL TAKE A FEW DEGREES OFF MET GUIDANCE...FOR HIGHS IN THE UPPER
80S TO LOWER 90S.
AS HAS BEEN THE CASE THE PAST COUPLE DAYS TO OUR NORTHWEST...THE
AREA OF LIFT VERY SLOWLY DRIFTS SOUTHEAST SO WILL MAINTAIN LOW
CHANCE POPS FOR AREAS EAST OF THE IL RIVER SUNDAY NIGHT...AND THE
SOUTHEAST THIRD INTO MONDAY MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY
BEHIND THE DEPARTING SYSTEM...HIGH PRESSURE BUILDING INTO THE
GREAT LAKES PROVIDES LIGHT NORTHERLY FLOW INTO MID-WEEK. 850 MB
TEMPS REMAIN QUITE WARM...ABOVE 20C SO WILL KEEP TEMPS A FEW
DEGREES ABOVE NORMAL. INTERESTING THAT MET GUIDANCE ALREADY PUSHES
HIGHS ABOVE 100 BY TUESDAY FOR SOUTHERN HALF OF THE AREA...BUT
GIVEN LIGHT FLOW/LIMITED MIXING WILL KNOCK A FEW DEGREES OFF
THESE NUMBERS.
NORTHWEST FLOW ALOFT CONTINUES TO DOMINATE THE WEATHER PATTERN
THROUGH THE REMAINDER OF THE EXTENDED FORECAST. DUE TO MODEL
DIFFERENCES IN TIMING AND LOCATION OF ANY SHORTWAVES...AND RECENT
TRENDS/DROUGHT WILL KEEP THE FORECAST DRY UNTIL A MORE SUBSTANTIAL
TROUGH SHIFTS INTO THE GREAT LAKES TOWARDS SATURDAY. TEMPERATURES
LOOK TO STAY SEVERAL DEGREES ABOVE NORMAL INTO NEXT WEEKEND.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1243 PM CDT SUN JUL 29 2012
.UPDATE...
BAND OF SHOWERS CONTINUES TO DISSIPATE THIS AFTERNOON AS IT
OUTRUNS THE SHORTWAVE THAT GENERATED IT...AND THE LOW LEVEL JET
WEAKENS AND BACKS ONCE AGAIN TO THE WEST. HOWEVER...ACROSS THE
SOUTHWEST HALF OF THE FORECAST AREA WE HAVE FULL SUNSHINE AND
PLENTY OF AVAILABLE MOISTURE TO BUILD INSTABILITY WITH. AM
CONCERNED ABOUT A CAP THAT MAY SUPPRESS ANY CONVECTIVE INITIATION.
MODELS WERE TOO WARM AT MID LEVELS AS COMPARED TO THIS MORNINGS
SOUNDING...SO ANTICIPATE THAT IT MAY BE EASIER TO GET CONVECTION
GOING THAN MOST OF THE MODELS HAVE IMPLIED. THE HRRR DOES SHOW
CONVECTION DEVELOPING THIS AFTERNOON IN A LINE EXTENDING FROM KMLI
BACK TO KMIW...AND THEN DROPPING SOUTHEAST DURING THE AFTERNOON.
MODEL SOUNDINGS IMPLY THAT OUR CONVECTIVE TEMPERATURE SHOULD BE IN
THE LOW TO MID 80S...SO WILL NEED TO KEEP AN EYE OUT FOR THIS IN
THE NEXT FEW HOURS. HAVE MADE SOME OTHER UPDATES TO FRESHEN UP
TEMPERATURES...DEWPOINTS...WINDS AND SKY COVER AS WELL AS THE
ABOVE DISCUSSED ADJUSTMENT FOR POPS.
&&
.AVIATION...
VFR CONDITIONS CONTINUE AT ALL TAF SITES. LIGHT RAIN SHOWERS TO
CLEAR KDBQ IN THE NEXT HOUR. NEW CONVECTION ANTICIPATED WHICH MAY
AFFECT KCID...KMLI AND POSSIBLY KBRL THIS AFTERNOON. THESE MAY
BRING MVFR CIGS AND VSBYS WITH GUSTY WINDS...BUT HAVE KEPT THINGS
TO VCTS IN TERMINALS DUE TO UNCERTAINTIES WITH TIMING AND SPECIFIC
LOCATION. ALL CONVECTION SHOULD CLEAR THE TERMINALS BY 00Z THIS
EVENING AND THEN WE WILL RETURN TO VFR CONDITIONS EVERYWHERE FOR
THE REMAINDER OF THE TAF PERIOD. LIGHT SOUTHEAST WINDS THIS
AFTERNOON TO GRADUALLY NORTHEAST LATE THIS AFTERNOON AND
EVENING...TO THEN CONTINUE INTO MONDAY MORNING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
LE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
213 PM MDT SUN JUL 29 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 120 PM MDT SUN JUL 29 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE CONTINUING TO
DOMINATE US PATTERN WITH CENTER OVER NORTHERN TEXAS. ALONG THE
WEST/NORTHWEST EXTENT OF THE RIDGE MONSOONAL MOISTURE CONTINUES TO
STREAM NORTH ACROSS THE INTER-MOUNTAIN WEST TOWARDS THE CWA. AT THE
SURFACE A LINGERING BAROCLINIC ZONE/DECAYED STATIONARY FRONT REMAINS
IN PLACE OVER THE CWA.
EARLY MORNING SHOWERS HAVE MOVED OFF TO THE EAST...WITH CLEARING
OCCURRING TO THE SOUTH AND WEST. MIXED LAYER CAPE VALUES ACROSS THE
AREA ARE CURRENTLY IN THE 500-1500 J/KG RANGE AND SHOULD INCREASE
WITH CLEARING AS LOW LEVEL LAPSE RATES STEEPEN. A WEAK SHORTWAVE
TROUGH IS PROGGED TO MOVE ACROSS SW NEBRASKA...AND MAY BE THE
FEATURE THAT HELPS GET THINGS GOING AGAIN TONIGHT. THE LATEST HRRR
WOULD INDICATE THAT THUNDERSTORM REDEVELOPMENT LIKELY WILL HOLD OFF
UNTIL AFTER 00Z...HOWEVER IT IS DEVELOPING WIDESPREAD CONVECTION
FURTHER SOUTH THAN WHAT THE LATEST NAM/GFS WOULD INDICATE...SO HAVE
KEPT POPS IN CHANCE CATEGORY THIS EVENING/OVERNIGHT. OVERALL SHEAR
IS WEAK AND THERE IS VERY LITTLE TO GET STORMS MOVING IN PROXIMITY
TO BAROCLINIC ZONE. WITH VERY HIGH PWAT VALUES IN EXCESS OF 1.5
HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE WITH THESE SLOW
MOVING THUNDERSTORMS. AS WITH YESTERDAY COVERAGE IS STILL A
QUESTION...WITH BEST COVERAGE RIGHT NOW EXPECTED TO BE ACROSS THE
NORTHERN HALF OTHER CWA OVERNIGHT IN PROXIMITY TO SHORTWAVE TROUGH.
WITH BAROCLINIC ZONE IN PLACE THROUGH MONDAY SHOWERS/THUNDERSTORMS
COULDNT BE RULED OUT THROUGH MONDAY AFTERNOON AS WEAK PULSES
CONTINUE TO MOVE WITHIN PROXIMITY OF THE CWA.
TEMPERATURES SHOULD BE COOLER ON MONDAY AFTERNOON HIGHS IN THE MID
TO UPPER 90S ACROSS THE CWA. EASTERLY FLOW WILL DEVELOP ACROSS THE
REGION...AND H85 TEMPS WILL MODERATE SOME WITH VALUES ABOUT 3C COOLER.
DEPENDING ON CLOUD COVER SOME LOCATIONS COULD SEE HIGHS ON MONDAY
CLOSER TO NORMAL VALUES IN THE LOW 90S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 205 PM MDT SUN JUL 29 2012
RIDGE OVER THE SOUTHERN PLAINS WILL DRIFT WESTWARD. TEMPERATURES
WILL CONTINUE TO BE ABOVE NORMAL. THE RIDGE IS FAR ENOUGH SOUTH
THAT SHORTWAVE TROUGHS COMING OVER THE TOP WILL BRING OCCASIONAL
CHANCES FOR THUNDERSTORMS. MODELS HINTING AT FAIRLY STRONG ONE
TUESDAY NIGHT WITH POSSIBLE MCS DEVELOPING IN EASTERN COLORADO AND
MOVING ACROSS THE FORECAST AREA. BUMPED POPS UP TO
CHANCE...ESPECIALLY IN THE WEST. THE PATTERN BASICALLY REPEATS
THROUGH THE END OF THE WEEK...SO COULD END UP WITH A RATHER WET
PATTERN. STRONG SYSTEM WILL MOVE ACROSS THE NORTHERN PLAINS ON
FRIDAY AND DRIVE A COLD FRONT THROUGH THE AREA. COOLER
TEMPERATURES FOLLOW ON SATURDAY...AT LEAST CLOSER TO NORMAL.
DESPITE THE POST FRONTAL UPSLOPE AT THE SURFACE...SHORTWAVE
RIDGING IS FORECAST OVER THE WEEKEND...SO THINK PRECIPITATION
CHANCES WILL COME TO AN END.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1129 AM MDT SUN JUL 29 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. LIGHT SHOWERS ARE IN THE PROCESS OF WEAKENING
AND MOVING EAST OF BOTH TERMINALS...AND SHOULD BE GONE BY VALID
TAF TIME. AS SKIES CLEAR INSTABILITY WILL BEGIN TO INCREASE. WITH
FRONTAL ZONE STILL LINGERING BETWEEN BOTH TERMINALS THUNDERSTORMS
SHOULD BEGIN TO RE-DEVELOP BY MID AFTERNOON AND SHIFT NORTH AND
EAST ACROSS THE AREA. CONFIDENCE IS STILL TOO LOW TO ZERO IN ON AN
EXACT TIME OF OCCURRENCE AT EITHER TERMINAL...SO LEFT VCTS IN
PLACE. THUNDERSTORM ACTIVITY MAY LINGER LONGER AT KMCK THROUGH THE
NIGHT AS A WEAK SHORTWAVE MOVES ACROSS NEBRASKA. WINDS GENERALLY
BE OUT OF THE EAST/SOUTHEAST BELOW 12KT THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
121 PM MDT SUN JUL 29 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 120 PM MDT SUN JUL 29 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE CONTINUING TO
DOMINATE US PATTERN WITH CENTER OVER NORTHERN TEXAS. ALONG THE
WEST/NORTHWEST EXTENT OF THE RIDGE MONSOONAL MOISTURE CONTINUES TO
STREAM NORTH ACROSS THE INTER-MOUNTAIN WEST TOWARDS THE CWA. AT THE
SURFACE A LINGERING BAROCLINIC ZONE/DECAYED STATIONARY FRONT REMAINS
IN PLACE OVER THE CWA.
EARLY MORNING SHOWERS HAVE MOVED OFF TO THE EAST...WITH CLEARING
OCCURRING TO THE SOUTH AND WEST. MIXED LAYER CAPE VALUES ACROSS THE
AREA ARE CURRENTLY IN THE 500-1500 J/KG RANGE AND SHOULD INCREASE
WITH CLEARING AS LOW LEVEL LAPSE RATES STEEPEN. A WEAK SHORTWAVE
TROUGH IS PROGGED TO MOVE ACROSS SW NEBRASKA...AND MAY BE THE
FEATURE THAT HELPS GET THINGS GOING AGAIN TONIGHT. THE LATEST HRRR
WOULD INDICATE THAT THUNDERSTORM REDEVELOPMENT LIKELY WILL HOLD OFF
UNTIL AFTER 00Z...HOWEVER IT IS DEVELOPING WIDESPREAD CONVECTION
FURTHER SOUTH THAN WHAT THE LATEST NAM/GFS WOULD INDICATE...SO HAVE
KEPT POPS IN CHANCE CATEGORY THIS EVENING/OVERNIGHT. OVERALL SHEAR
IS WEAK AND THERE IS VERY LITTLE TO GET STORMS MOVING IN PROXIMITY
TO BAROCLINIC ZONE. WITH VERY HIGH PWAT VALUES IN EXCESS OF 1.5
HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE WITH THESE SLOW
MOVING THUNDERSTORMS. AS WITH YESTERDAY COVERAGE IS STILL A
QUESTION...WITH BEST COVERAGE RIGHT NOW EXPECTED TO BE ACROSS THE
NORTHERN HALF OTHER CWA OVERNIGHT IN PROXIMITY TO SHORTWAVE TROUGH.
WITH BAROCLINIC ZONE IN PLACE THROUGH MONDAY SHOWERS/THUNDERSTORMS
COULDNT BE RULED OUT THROUGH MONDAY AFTERNOON AS WEAK PULSES
CONTINUE TO MOVE WITHIN PROXIMITY OF THE CWA.
TEMPERATURES SHOULD BE COOLER ON MONDAY AFTERNOON HIGHS IN THE MID
TO UPPER 90S ACROSS THE CWA. EASTERLY FLOW WILL DEVELOP ACROSS THE
REGION...AND H85 TEMPS WILL MODERATE SOME WITH VALUES ABOUT 3C COOLER.
DEPENDING ON CLOUD COVER SOME LOCATIONS COULD SEE HIGHS ON MONDAY
CLOSER TO NORMAL VALUES IN THE LOW 90S.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1129 AM MDT SUN JUL 29 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. LIGHT SHOWERS ARE IN THE PROCESS OF WEAKENING
AND MOVING EAST OF BOTH TERMINALS...AND SHOULD BE GONE BY VALID
TAF TIME. AS SKIES CLEAR INSTABILITY WILL BEGIN TO INCREASE. WITH
FRONTAL ZONE STILL LINGERING BETWEEN BOTH TERMINALS THUNDERSTORMS
SHOULD BEGIN TO RE-DEVELOP BY MID AFTERNOON AND SHIFT NORTH AND
EAST ACROSS THE AREA. CONFIDENCE IS STILL TOO LOW TO ZERO IN ON AN
EXACT TIME OF OCCURRENCE AT EITHER TERMINAL...SO LEFT VCTS IN
PLACE. THUNDERSTORM ACTIVITY MAY LINGER LONGER AT KMCK THROUGH THE
NIGHT AS A WEAK SHORTWAVE MOVES ACROSS NEBRASKA. WINDS GENERALLY
BE OUT OF THE EAST/SOUTHEAST BELOW 12KT THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER/PMM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1129 AM MDT SUN JUL 29 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MAIN FORECAST PROBLEM WILL BE PRECIPITATION CHANCES THROUGH THE
SHORT TERM. SATELLITE SHOWING THE FLOW HAS DEAMPLIFIED OVER THE LAST
24 HOURS ACROSS MOST OF THE PACIFIC. THIS FLOW THEN TRANSITIONS TO
THE UPPER TROUGH NEAR THE WEST COAST WITH PERSISTENT/BROAD UPPER
RIDGE REMAINING ANCHORED OVER THE CENTER OF THE COUNTRY. CENTER OF
THIS RIDGE HAS MOVED SOUTHEAST FROM YESTERDAY...HOWEVER THE RIDGE HAS
ELONGATED TO THE NORTHWEST.
SATELLITE/UPPER AIR ANALYSIS SHOWS STRONG SUBTROPICAL MOISTURE FEED
AROUND THE WEST AND NORTHERN PORTION OF THE HIGH. BESIDES A SMALL
INCREASE IN MID LEVEL MOISTURE...THE AIR MASS REMAINS NEARLY THE
SAME FROM YESTERDAY. AT MID LEVELS...THE GFS/UKMET WERE DOING A
LITTLE BETTER THAN THE CANADIAN/SREF WITH THE NAM INITIALIZING THE
WORST OF THE BUNCH...ESPECIALLY ON THE CENTER POSITION OF THE RIDGE.
ONGOING CONVECTION AND OUTFLOW BOUNDARIES MAKING A LITTLE HARDER TO
GET A GOOD HANDLE ON THE SURFACE. THE SREF/RUC/HRRR WERE CATCHING
BETTER THAN THE NAM AND ECMWF. MODELS WERE PRETTY CLOSE ON THE LOW
LEVEL THERMAL FIELD. THE NAM/CANADIAN/SREF WERE DOING SLIGHTLY
BETTER.
NAM THROUGH 06Z HAS PRECIPITATION COVERAGE UNDERDONE THAT WAS
OVER/NEAR THE EAST/SOUTHEAST PORTION OF THE AREA. IT PUT MORE
EMPHASIS/PRECIPITATION ON THE WESTERN END OF THE SURFACE THAN IN THE
EAST. TO SOME EXTENT ALL THE MODELS SHOW THAT BIAS. THE SREF AND TO
A LESSER EXTENT THE CANADIAN GOT THAT PRECIPITATION RIGHT. FROM
YESTERDAY...THE RUC AND HRRR STARTED THE PRECIPITATION FURTHER NORTH
AND EAST AND WAS THE MOST CORRECT. THE HRRR TONIGHT IS CATCHING THE
CURRENT PRECIPITATION AREA IN THE EAST WELL.
TODAY/TONIGHT...OVERNIGHT CONVECTION WILL PROBABLY LEAVE AROUND
LEFTOVER BOUNDARIES. MOST MODELS ARE INSISTENT OF STARTING CONVECTION
BY 18Z. SURFACE BOUNDARY NEAR THE SOUTHERN PORTION OF THE AREA WITH
A WEAK SHORTWAVE TROUGH NEAR THE WESTERN PORTION OF THE AREA AT THE
BEGINNING OF THE DAY AS WELL. MODELS HAVE BEEN SIMILAR IN HAVING
THE BEST CHANCE OF PRECIPITATION IN THE WEST AND NORTHERN PORTION OF
THE AREA. SREF AND GEFS PROBABILITIES MATCH UP WHERE THE DEEPEST
LIFT IS. SO ADJUSTED THE CHANCE POPS FURTHER EAST.
MODELS STILL SHOWING IT WARM TODAY. KEPT IT CLOSE TO WHAT THE
WARMEST GUIDANCE WHICH WAS CLOSE TO THE PREVIOUS FORECAST.
MONDAY...THERE LOOKS TO BE SOME LINGERING STORMS IN THE MORNING
IN THE EAST. AFTER THAT MODELS STILL HAVING TROUBLE WITH THIS DAY ON
THE PRECIPITATION. LIFT REMAINS AROUND ALL DAY AT MID LEVELS WITH
SURFACE SYNOPTIC TROUGH HANGING AROUND SOMEWHERE IN THE AREA WITH
POSSIBLE MESOSCALE BOUNDARIES AND WITH LITTLE TO NO CINH MAKE IT
POSSIBLE FOR THUNDERSTORMS TO BREAK ABOUT ANYWHERE IN THE
AFTERNOON. SO AGAIN BROADBRUSHED SLIGHT CHANCES. EASTERLY WINDS...
AND LINGERING CLOUD COVER AND WITH SLIGHTLY COOLER 850 MB
TEMPERATURES MAKE FOR A LITTLE COOLER DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1129 AM MDT SUN JUL 29 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. LIGHT SHOWERS ARE IN THE PROCESS OF WEAKENING
AND MOVING EAST OF BOTH TERMINALS...AND SHOULD BE GONE BY VALID
TAF TIME. AS SKIES CLEAR INSTABILITY WILL BEGIN TO INCREASE. WITH
FRONTAL ZONE STILL LINGERING BETWEEN BOTH TERMINALS THUNDERSTORMS
SHOULD BEGIN TO RE-DEVELOP BY MID AFTERNOON AND SHIFT NORTH AND
EAST ACROSS THE AREA. CONFIDENCE IS STILL TOO LOW TO ZERO IN ON AN
EXACT TIME OF OCCURRENCE AT EITHER TERMINAL...SO LEFT VCTS IN
PLACE. THUNDERSTORM ACTIVITY MAY LINGER LONGER AT KMCK THROUGH THE
NIGHT AS A WEAK SHORTWAVE MOVES ACROSS NEBRASKA. WINDS GENERALLY
BE OUT OF THE EAST/SOUTHEAST BELOW 12KT THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BULLER/PMM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1133 AM CDT SUN JUL 29 2012
.DISCUSSION...
THIN CIRRUS OVERHEAD WITH TEMPERATURES RIGHT ON TRACK. NO CHANGES
TO HIGHS...BUT SLIGHT TWEAKS TO DEW POINTS DURING THE MID TO LATE
AFTERNOON. WE WILL CONTINUE THE HEAT ADVISORY AS WE WILL BUCK
WARNING CRITERIA WHERE RAIN DID FALL YESTERDAY. HARD TO SAY WHERE
A CU FIELD MAY CROP UP BUT OUR SOUNDING AND UPSTREAM LITTLE ROCKS
IS PRETTY DRY IN THE LOW LEVELS WHILE LAKE CHARLES AND JACKSON ARE
180 OUT. SO THINKING FROM MONROE TO LUFKIN AND SOUTH FOR LOW LEVEL
CONVERGENCE OF ANY SORT. HAVE INCREASED POPS...BUT STILL ONLY A
SILENT CHANCE FOR ISOLATED ACTIVITY WHICH A NOWCAST WILL MORE THAN
HANDLE. ALTHOUGH RAP DOES SHOW QPF OVER DEEP EAST TEXAS THIS
MORNING...JUST LEFT OVER POOLED MOISTURE FROM YESTERDAY AND THEN
NOTHING IN THE HEAT OF MIDAFTERNOON...BUT MORE QPF THERE LATE IN
THE DAY. REALITY CHECK SHOWS ECHOES OFF SHORE FOR THE MOST PART
AT THIS TIME. AN OUTFLOW BOUNDARY HAS JUST CROPPED UP ON KLCH 88D
AND IS MOVING NE AND COULD TURN AROUND SOME LOW LEVEL STUFF...BUT
ANYTHING THUNDERING WOULD SLIDE RIGHT BACK WESTWARD BASED ON THEIR
SOUNDING. HPC LATEST SHOWS NO QPF AND SPC/S GENERAL LINE IS RIDING
OUR SOUTHERN TIER. SO WILL MONITOR FOR ANYTHING SPECIAL...BUT THE
UPPER RIDGE IS STRONGEST OVER OUR NW QUAD OF COUNTIES WITH LITTLE
IF ANY CHANCE FOR I-30 CORRIDOR AND MAY EVEN BE LEANING OVER I-20
A GOOD BIT. /24/
&&
.AVIATION...
VFR FLIGHT CONDITIONS WILL BE COMMON ACROSS THE ARKLATEX THIS
PERIOD...AS HIGH PRESSURE ALOFT CONTINUES TO INFLUENCE A DRY WEATHER
PATTERN. WX WILL CONTINUE TO BE ABSENT FROM THE 18Z TAF
PACKAGE...BUT ISOLATED TSRA ACTIVITY CAN NOT BE TOTALLY RULED OUT
THIS AFTERNOON. ANY TSRA ACTIVITY NEAR TERMINALS WILL BE HANDLED
WITH AN AMD. LIGHT AND VARIABLE WINDS WILL CONTINUE...WITH NO VSBY
CONCERNS EXPECTED IN THE 18Z PACKAGE. /11/
&&
.PREV DISCUSSION... /ISSUED 256 AM CDT SUN JUL 29 2012/
DISCUSSION...
UPPER LEVEL RIDGE CENTERED OVER NORTH TEXAS AND SOUTHERN OKLAHOMA WILL
REMAIN IN PLACE THROUGH MONDAY. THIS WILL BRING BASICALLY NO RAIN
AND AND VERY HOT TEMPERATURES TO THE FOUR STATE REGION. COMBINED
WITH THE HIGH DEWPOINTS...THE HEAT INDEX VALUES WILL TOP 105 OVER
MOST OF THE AREA TODAY AND MONDAY. CANNOT RULE DEVELOPMENT OF
CONVECTION DURING THE HOTTEST PART OF DAY...BUT IF ANY...IT WILL
BE VERY LOCALIZED. THE CENTER OF THE RIDGE WILL SHIFT WEST
TUESDAY INTO WEST TEXAS AND WEAKEN SLIGHTLY. THIS MAY ALLOW
TEMPERATURES TO EASE A BIT. BY THURSDAY...AN INCREASE IN MOISTURE
ON THE EAST SIDE OF THE RIDGE...COMBINED WITH WEAK UPPER LEVEL
DISTURBANCES...MAY RESULT IN FEW SHOWERS AND THUNDERSTORMS...MAINLY
EASTERN AREAS. THIS PATTERN...WITH ISOLATED AFTERNOON CONVECTION WILL
CONTINUE INTO NEXT WEEKEND.
A HEAT ADVISORY HAS BEEN ISSUED FOR TODAY AND MONDAY TO COVER THE
EXCESSIVE HEAT.
AVIATION...
STRONG UPPER LEVEL RIDGE OVER THE REGION AND DRY CONDITIONS WILL
ALLOW VFR CONDITIONS TO PREVAIL THROUGH THE TAF PERIOD. SOME CONCERN
THAT A WEAK UPPER LEVEL DISTURBANCE MOVING SOUTH THROUGH MISSOURI
MAY PROVIDE JUST ENOUGH SUPPORT FOR ISOLATED CONVECTION THIS
AFTERNOON...MAINLY ACROSS N LA/SRN AR. HOWEVER...CONFIDENCE IS
LOW SO WILL LIKELY NOT INCLUDE ANY TSTM REMARKS WITH THE 12Z TAF
ISSUANCE. OTHERWISE...WLY SFC WINDS ARE EXPECTED ACROSS E TX VEERING
TO NELY OVER NW LA/SRN AR. SPEEDS WILL BE BETWEEN 5-10 KTS DURING
THE DAYTIME BEFORE BECOMING LIGHT AND VARIABLE AFTER SUNSET SUNDAY.
/09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 103 77 101 77 102 / 10 10 10 10 0
MLU 101 75 100 75 99 / 10 10 10 10 10
DEQ 102 72 104 74 102 / 10 10 10 10 0
TXK 101 76 104 76 101 / 10 10 10 10 0
ELD 101 74 103 74 102 / 10 10 10 10 10
TYR 102 76 103 77 100 / 10 10 0 0 0
GGG 102 74 102 76 100 / 10 10 10 10 0
LFK 99 76 99 76 98 / 10 10 10 10 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
ARZ050-051-059>061-070>073.
LA...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
LAZ001>006-010>014-017>022.
OK...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
OKZ077.
TX...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
TXZ096-097-108>112-124>126-136>138-149>153-165>167.
&&
$$
24/11
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 PM EDT SUN JUL 29 2012
.UPDATE...
ISSUED AT 1248 PM EDT SUN JUL 29 2012
WILL NEED TO KEEP AN EYE ON THE NEAR TERM...WITH THE LINE OF WARNED
TSRA THAT DEVELOPED DURING THE MORNING HOURS NORTH OF MN IN ONTARIO.
WHILE MUCH OF THE STRONGER ACTIVITY WILL LIKELY REMAIN IN CANADIAN
WATERS...THE NEARLY 35KT SE TRACK ACROSS ISLE ROYALE BY 20Z...AND
THE KEWEENAW PENINSULA BY 22Z IF TSRA REMAIN AT THE CURRENT SPEED.
WILL CONTINUE TO MONITOR AND INCREASE CLOUD COVER AS IT BLOWS OFF
OUT AHEAD OF THE STORMS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 125 PM EDT SUN JUL 29 2012
HIGH PRESSURE IS EXITING TO OUR SE...WITH A RIDGE REMAINING OVERHEAD
THROUGH THE EVENING HOURS. AN UPPER LEVEL DISTURBANCE IN CHARGE OF
HELPING TO CREATE TSRA ACTIVITY OVER W ONTARIO/N MN THIS AFTERNOON
HAS THE BEST CHANE OF INFLUENCING CMX BY LATE AFTERNOON WITH MOSTLY
MORE CLOUDS. POP UP CONVECTION COULD ALSO GET TO SAW BEFORE SUNSET
AS WELL...BUT WITH THE LOW PROBABILITY AND LIMITED IMPACT...IT HAS
BEEN KEPT OUT OF THE FCST FOR NOW.
NEARING LOW PRESSURE STRETCHING FROM W ND THROUGH
MANITOBA WILL BECOME BETTER ORGANIZED AS IT BECOMES DRAPED FROM THE
ARROWHEAD OF MN TO JAMES BAY BY 12Z MONDAY. THE MAIN RESULT AT THE
TAF SITES WILL BE INCREASED CLOUD COVER...AND A SMALL CHANCE OF RAIN
SHOWERS /VCSH ADDED DUE TO UNCERTAINTY/ AS THE LOW SLIDES ACROSS W
LAKE SUPERIOR BY EARLY AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KF
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1248 PM EDT SUN JUL 29 2012
.UPDATE...
ISSUED AT 1248 PM EDT SUN JUL 29 2012
WILL NEED TO KEEP AN EYE ON THE NEAR TERM...WITH THE LINE OF WARNED
TSRA THAT DEVELOPED DURING THE MORNING HOURS NORTH OF MN IN ONTARIO.
WHILE MUCH OF THE STRONGER ACTIVITY WILL LIKELY REMAIN IN CANADIAN
WATERS...THE NEARLY 35KT SE TRACK ACROSS ISLE ROYALE BY 20Z...AND
THE KEWEENAW PENINSULA BY 22Z IF TSRA REMAIN AT THE CURRENT SPEED.
WILL CONTINUE TO MONITOR AND INCREASE CLOUD COVER AS IT BLOWS OFF
OUT AHEAD OF THE STORMS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 724 AM EDT SUN JUL 29 2012
EXPECT VFR CONDITIONS/LGT WINDS TODAY WITH HI PRES DOMINATING. THE
APRCH OF A DISTURBANCE LATER TNGT MAY BRING SOME SOME SHRA/TS TO
MAINLY CMX...BUT CONCERNS ABOUT SUFFICIENT MSTR RETURN/TIMING AND
COVERAGE DO NOT ALLOW FOR A FCST OF MORE THAN VCSH ATTM. VFR
CONDITIONS SHOULD BE THE RULE TNGT AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED FOR 18Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1240 PM CDT SUN JUL 29 2012
.DISCUSSION...ISSUED 415 AM CDT
SHORT WAVE NEAR WILLMAR THIS MORNING HAS DRIVEN SHOWERS ACROSS THE
AREA THIS PAST NIGHT. ELEVATED SHOWERS ACROSS WRN WI OVER TO THE
NRN TWIN CITIES ARE WITHIN A ZONE OF WEAK FGEN/ISENTROPIC LIFT
AROUND H6...ACTIVITY WEST OF THE CITIES IS ASSOCIATED WITH THE
SHORTWAVE...WHILE MOST ROBUST AREA OF CONVECTION ACROSS SOUTH
CENTRAL MINNESOTA IS ON THE NOSE OF THE LLJ. THE RAP SHOWS THIS
UPPER WAVE REACHING LA CROSSE BY 15Z...WITH ASSOCIATED FORCING
MOVING TO THE SOUTHEAST THROUGH THE REST OF THE MORNING. SRN MN
CONVECTION WILL CERTAINLY CONTINUE TO FOCUS BRUNT OF PRECIP TO THE
SOUTH...BUT SHOULD CONTINUE TO SEE LIGHT SHOWERS FOLLOW THE H7/H5
LOW SE ACROSS THE AREA THIS MORNING...WITH A MAJORITY OF RAIN
FALLING ALONG AND SOUTH OF I-94. BASED ON RAP TIMING OF THE
SHORTWAVE AND REFLECTIVITY FORECASTS FROM MOST CAMS...EXPECT MOST
OF THIS PRECIP TO BE OUT OF THE MPX CWFA BY 15Z. IN THE RAINS
WAKE...SKIES WILL BE CLEARING OUT FROM WEST TO EAST. H85 TEMPS
WILL RANGE FROM AROUND +22C WEST TO +16 EAST...WHICH SHOULD ALLOW
FOR LOWER 90S TO LOWER 80S FOR HIGHS RESPECTIVELY.
FOR TONIGHT...STRONG WAVE CURRENTLY SPINNING ACROSS SRN SASK WILL
RUN ALONG THE MN/ONTARIO BORDER...DRIVING A COLD FRONT INTO NRN
MN. CAMS AND SREF PROBS ALL SIMILAR WITH DEVELOPING SCT STORMS
ALONG THE FRONT THIS AFTERNOON FROM ERN NODAK INTO NW MN. THIS
FRONT WILL BE MOVING INTO CENTRAL MN BY 12Z MONDAY...SO INTRODUCED
SOME SMALL POPS ACROSS CENTRAL MN LATE TONIGHT TO ACCOUNT FOR
THAT. DURING THE DAY MONDAY...THIS FRONT WILL DROP ACROSS THE
AREA...EXITING THE S/SE MPX CWFA BETWEEN 21Z AND 00Z. BEST FLOW AT
H85 AND CONVERGENCE ALONG THE BOUNDARY STILL PEGGED TO BE ACROSS
THE U.P. OF MICH INTO NRN WI...WHERE GREATEST POTENTIAL FOR STORMS
WILL EXIST. CONTINUED A NARROW RIBBON OF SLIGHTS ALONG THE FRONT
MONDAY AFTERNOON WITH THE NAM ADVERTISING 2-3000 J/KG OF MUCAPE
ALONG THE FRONT. GIVEN THE FRONTS EXPECTED MOVEMENT...DID TRIM
BACK HOW FAR NORTH POPS ARE MENTIONED MONDAY AFTERNOON. ALSO LOOKS
WARM AGAIN MONDAY...WITH H85 TEMPS WARMING INTO THE 20S C FOR MOST
OF THE AREA...CONTINUED TO ADVERTISE UPPER 80S TO LOWER 90S HIGHS
MONDAY AFTERNOON...WITH 90S CREEPING UP TO ABOUT I-94.
FOR THE REST OF THE FORECAST...WILL BE REMAINING NORTH OF THE MAIN
UPPER RIDGE...WELL WITHIN THE JET STREAMS TERRITORY. STILL LOOKING
AT TWO POTENTIAL ACTIVE PERIODS IN THE TUESDAY THROUGH SUNDAY
TIMEFRAME. THE FIRST WILL BE ANOTHER WEAK NW FLOW WAVE THE MODELS
SHOW CRESTING THE RIDGE WEDNESDAY INTO WEDNESDAY NIGHT...SENDING A
VERY WEAK BOUNDARY ACROSS THE REGION. LIKE MONDAYS FRONT...H85
FLOW WILL BE LACKING WITH THE WEDNESDAY WAVE...AND PRECIP CHANCES
ARE LOOKING SCANT AT BEST WITH THIS WAVE...SO CONTINUED TO CAP
POPS AT 40 PERCENT...WITH BEST CHANCES RUNNING ACROSS CENTRAL MN
INTO WRN WI...WHICH IS WHERE THE ECMWF SHOWS THE SRN END OF A LLJ
WORKING THROUGH.
SHOULD SEE ANOTHER BREAK FROM THE PRECIP ACROSS THE AREA
THURSDAY...BEFORE A MORE SIGNIFICANT UPPER WAVE MOVES ACROSS THE
UPPER MS VALLEY SOMETIME ON FRIDAY /ECMWF AND GEM/ OR SATURDAY
/GFS/. ECMWF IS MOST AGGRESSIVE WITH THE WAVE...BRING A NEUTRAL TO
NEG TILTED TROUGH THROUGH...WITH THE GFS SHOWING A WEAKER
POSITIVELY TILTED TROUGH WORKING THROUGH SATURDAY. GIVEN TIMING
DIFFERENCES...BLENDING PROCEDURE ENDED UP SMEARING CHANCE POPS
ACROSS BOTH DAYS. HOWEVER...DESPITE THE TIMING DIFFERENCES...BOTH
THE GFS AND ECMWF SHOW THIS FRONT PACKING QUITE A PUNCH IN TERMS
OF COOLER/DRIER AIR BEHIND IT...WITH BOTH ADVERTISING A 1020 MB
HIGHS SETTLING IN BEHIND THIS SYSTEM. TILL THEN THOUGH...HIGHS IN
THE MID 80S TO LOWER 90S WILL BE THE NORM.
.CLIMATE...
QUICK CHECK THROUGH THE CLIMATE DATA FOR THE TWIN CITIES FOR
NUMBER OF DAYS IN A MONTH WHERE HIGHS WERE BELOW 80 SHOWS THAT
THERE HAS NEVER BEEN A MONTH IN THE TWIN CITIES WHERE THERE WAS
NOT AT LEAST ONE DAY WITH A HIGH LESS THAN 80 /JULY OF 1936 AND
1916 BOTH HAD ONE SUB 80 DEGREE DAY/. TO THIS POINT...THE
"COLDEST" HIGH THIS MONTH WAS AN 80 ON THE 27TH. BASED ON CURRENT
FORECAST...THIS JULY LOOKS LIKE IT WILL BE THE FIRST MONTH IN
RECORDED HISTORY FOR THE TWIN CITIES WHERE WE FAILED TO SEE AT
LEAST ONE DAY LESS THAN 80. THE LAST SUB 80 HIGH WAS BACK ON JUNE
25TH.
&&
.AVIATION.../18Z TAF ISSUANCE/
VORT WHICH BROUGHT RATHER WDSPRD RAINS THIS MRNG NOW SE OF MSP NEAR
RGK TAKING PCPN WITH IT. SOME SUBSIDENCE IMMEDIATELY BEHIND THIS
FEATURE HAS SUPPRESSED CU DVLPMT...BUT CU HAS BEEN DEVELPING ACROSS
RWF/STC AND WILL BE DEVELOPING ACROSS REMAINING TAFS NEXT 2-3 HOURS.
SOME THREAT OF STATUS/FOG DEVELOPMENT OVERNIGHT...BUT INCREASING
MID/HI CLDS AND INCREASING SWLY GRADIENT AHD OF INCOMING CDFNT MAY
LIMIT DEVELOPMENT SOMEWHAT. BEST POTENTIAL FOR IFR/MVFR SHUD BE IN
EAU. SCT SHWRS/PSBL TSTM 08Z-12Z AXN/STC AHD OF CDFNT. LOOK FOR
WIND GUSTS TO 20 KTS BHND CDFNT.
KMSP...MID CLDS ARE THINNING AS VORT DROPS SE OF AREA. SHUD SEE VFR
CU DEVELOPING NEXT 1-2 HOURS. SOME THREAT OF MVFR CIGS/VSBYS ARND
08Z. HOWEVER...INCREASING UPSTREAM MID/HI CLDS AND INCREASING SW
GRADIENT AHD OF APRCHG CDFNT COULD PREVENT THIS DEVELOPMENT.
//OUTLOOK
MONDAY... VFR.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR EXPECTED.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/BAP
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1225 PM CDT SUN JUL 29 2012
.UPDATE...MADE VERY LITTLE IN THE WAY OF NOTABLE CHANGES TO THE
AFTERNOON FORECAST. LEFT AFTERNOON SHOWER/STORM CHANCES PRETTY
MUCH WHERE PREVIOUS FORECAST HAD THEM...BUT DID EXPAND THEM VERY
SLIGHTLY NORTHEASTWARD...NOW COVERING AREAS MAINLY SOUTHWEST OF AN
ELWOOD-BELOIT LINE. ALSO INCREASED POPS TO 30 PERCENT FOR THE LATE
AFTERNOON TIME FRAME ACROSS A FEW FAR SOUTHWEST COUNTIES...AS A
FEW OF THE LIGHT SHOWERS CURRENTLY POSITIONED JUST WEST OF THE
SOUTHWESTERN CWA COULD EVENTUALLY INTENSIFY/EXPAND IN COVERAGE A
BIT. THE ONGOING ACTIVITY IN SOUTHWEST NEB/NORTHWEST KS APPEARS TO
BE TIED TO A SUBTLE ZONE OF MID LEVEL CONVERGENCE EVIDENT AT
700MB...WITH A CONTINUED SLOW BUT STEADY EASTWARD PROGRESSION OF
POSSIBLE PRECIPITATION AND THE ASSOCIATED MID-HIGH LEVEL CLOUD
SHIELD EXPECTED. STILL NOT THINKING MUCH OF A SEVERE THREAT LATER THIS
AFTERNOON...BUT A FEW STRONG STORMS IN THE SOUTHWEST CERTAINLY NOT
OUT OF THE QUESTION. TEMP-WISE...THINGS ARE VERY MUCH ON TRACK
FROM PREVIOUS FORECAST...BUT DID NUDGE SOME AREAS DOWN 1-2
DEGREES BASED ON GENERAL EXPECTATION OF SLOWLY INCREASING CLOUD
COVER AS THE AFTERNOON WEARS ON. EVEN SO...MID-UPPER 90S WILL
PREVAIL IN NEB ZONES...WITH 100-104 MORE COMMON IN KS. DID
INCREASE AFTERNOON DEWPOINTS A BIT ESPECIALLY ACROSS THE SOUTHEAST
2/3 OF THE CWA...WHICH RESULTS IN HEAT INDEX VALUES STILL AT OR
NEAR ADVISORY CRITERIA OF 105 OVER KS ZONES...SO LET HEADLINE RIDE
AS-IS. NOT SURE IF NORTHWEST COUNTIES WILL SEE SOME OF THE 40S
DEWPOINTS THAT THE 12Z NAM CONTINUES TO ADVERTISE...BUT THERE IS
IN FACT A DRY POCKET OF AIR NOTED ON 17Z OBS AT BROKEN BOW AND
THEDFORD...SOME OF WHICH COULD WORK INTO PARTS OF THE NORTHWEST
CWA EVENTUALLY.
&&
.AVIATION...18Z KGRI TAF. VFR VISIBILITY/CEILING ARE FORECAST
THROUGH THE NEXT 24 HOURS...ALTHOUGH MID LEVEL CLOUDS MAINLY AT OR
ABOVE 10,000 FEET WILL GRADUALLY BE ON THE INCREASE. ITS CERTAINLY
NOT OUT OF THE QUESTION THAT A FEW THUNDERSTORMS COULD AFFECT THE
TERMINAL TONIGHT...BUT WITH BETTER CHANCES FOCUSING AT LEAST 50
MILES TO THE SOUTHWEST...WILL OMIT ALL MENTION OF PRECIPITATION IN
THE TAF FOR NOW AND LET LATER SHIFTS INTRODUCE IF CONFIDENCE
INCREASES. AS FOR VISIBILITY...LIGHT EASTERLY BREEZES COULD RESULT
IN SOME LIGHT HAZE OVERNIGHT...BUT NOT ANTICIPATING ANYTHING BELOW
7SM AT THIS TIME. SPEAKING OF BREEZES...RELATIVELY LITTLE CHANGE IS
EXPECTED OVER THE NEXT 24 HOURS...WITH SUSTAINED SPEEDS AVERAGING
AT OR BELOW 10KT...AND DIRECTION LARGELY STAYING WITHIN 30
DEGREES EITHER SIDE OF DUE EASTERLY.
&&
.PREV DISCUSSION... /ISSUED 430 AM CDT SUN JUL 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERNS LIE WITH PRECIPITATION CHANCES...AND TEMPERATURES.
BEEN LITTLE OVERALL CHANGE IN THE UPPER LEVEL PATTERN ACROSS THE
REGION...WITH SATELLITE AND PROFILER DATA SHOWING IT REMAINING
DOMINATED BY UPPER LEVEL HIGH PRESSURE/RIDGING CENTERED JUST WEST
OF THE CWA. THIS LEAVES NORTHWESTERLY FLOW IN PLACE...WITH A
DISTURBANCE SHIFTING SOUTHEAST THIS MORNING...RIDING AROUND THE
EDGE OF THE RIDGE. CONTINUING TO SEE A FEW SHOWERS/THUNDERSTORMS
LINGER IN FAR SWRN PORTIONS OF THE CWA EARLY THIS MORNING
RESULTING FROM THIS DISTURBANCE...BUT EXPECT THEM TO EXIT THE CWA
OVER THE NEXT COUPLE HOURS. SEEING A WEAK SURFACE PATTERN IN PLACE
OVER THE CWA...BRINGING LIGHT AND VARIABLE WINDS EARLY THIS
MORNING...THOUGH A WEAK BOUNDARY IS IN PLACE JUST SOUTH OF THE
CWA.
FOR TODAY AND TONIGHT...NO SIGNIFICANT CHANGES WERE MADE TO THE
INHERITED FORECAST. KEPT THE FIRST HALF THE DRY QUIET...WITH
THUNDERSTORM CHANCES RETURNING DURING THE LATE AFTERNOON AND INTO
THE OVERNIGHT HOURS. MODELS NOT IN TOO BAD OF AGREEMENT SHOWING
THE SURFACE BOUNDARY REMAINING NEAR/JUST SOUTH OF THE CWA
THROUGH THE DAYTIME HOURS...AND AS ANOTHER WEAK UPPER LEVEL
DISTURBANCE LOOKS TO ROUND THE EDGE OF THE RIDGE AND MOVE INTO THE
REGION...THUNDERSTORM CHANCES WILL INCREASE. TIMING/OVERALL
COVERAGE REMAINS UNCERTAIN...LITTLE MORE DIFFERENCE BETWEEN
MODELS...NAM CONTINUES TO SHOW AN EARLIER ONSET OF ACTIVITY...VS
OTHERS LIKE THE 06Z HRRR WHICH IS QUIET THRU 21Z...AND THE 00Z 4KM
WRF WHICH SHOWS VERY LITTLE GOING ON AT ALL. BECAUSE OF THESE
DIFFERENCES KEPT POPS THOUGH TONIGHT LOW. COULD SEE A FEW
THUNDERSTORMS ON THE STRONG SIDE...BUT WITH DEEPER LAYER SHEAR
AGAIN ON THE WEAKER SIDE...CHANCES FOR SEVERE WEATHER IS LOW.
AS FAR AS TEMPERATURES GO...WITH THE MORE EASTERLY COMPONENT TO
THE WINDS /ESP ACROSS SC NEB/ STILL EXPECTED...AGAIN MADE FEW
CHANGES. MID/UPPER 90S ARE IN PLACE ACROSS THE NORTH...WITH LOWER
100S POSSIBLE ACROSS NC KS. ENDED UP ISSUING A HEAT ADV FOR NC KS
THIS AFTERNOON...WHERE POTENTIAL FOR HEAT INDEX VALUES NEAR 105
LIES...WITH TEMPS NEAR/JUST ABOVE 100 POSSIBLE AND HIGHER
DEWPOINTS EXPECTED AS THAT AREA SITS NEAR/JUST NORTH OF THE SFC
FRONT. CERTAINLY NOT A SLAM DUNK ADVISORY...A COUPLE OF THINGS
COULD POTENTIALLY MESS UP THE FORECAST HIGHS IN NC KS...SUCH AS
EVEN HIGHER DEWPOINTS THAN CURRENTLY FORECAST /SOME DATA SHOWS
DPTS CLOSER TO THE MID TO UPPER 60S VS THE NEAR 60
FORECAST/...AND/OR HIGHER CLOUD COVER THAN WHAT IS CURRENTLY
FORECAST DURING THE PEAK OF THE AFTERNOON. DECIDED TO GO WITH THE
AREA THAT HAD THE BEST POTENTIAL TO MEET CRITERIA...ALSO THINKING
THE AFFECTS OF ANY THUNDERSTORM DEVELOPMENT WOULD HOLD OFF UNTIL
LATER IN THE AFTERNOON.
GETTING INTO MONDAY AND TUESDAY...AGAIN SEE LITTLE CHANGE IN THE
OVERALL UPPER LEVEL PATTERN...AND CONFIDENCE IN PRECIPITATION
CHANCES REMAINS ON THE LOW SIDE. THE CWA REMAINS UNDER THE
INFLUENCE OF THAT UPPER LEVEL RIDGE...BUT IT DOESNT EXTEND FAR
ENOUGH NORTH TO KEEP US OUT OF THE WAY OF ANY WEAK DISTURBANCE
MAKING THEIR WAY AROUND THE EDGE OF THE RIDGE. ALONG WITH THE
POTENTIAL FOR DISTURBANCES MOVING THROUGH...MODELS NOT IN TOO BAD
OF AGREEMENT SHOWING THIS LINGERING SURFACE BOUNDARY GENERALLY
NEAR/SOUTH OF THE NEB/KS STATE LINE. THOUGH THERE ARE POPS IN
PLACE THROUGH TUESDAY NIGHT...CERTAINLY DONT WANT TO GIVE OFF THE
IMPRESSION THAT THERE ARE GOOD/WIDESPREAD POSSIBILITIES THE ENTIRE
TIME. THE ISSUE IS THAT AT EVEN THIS POINT...JUST A DAY OR TWO
OUT...THERE IS STILL ENOUGH UNCERTAINTY WITH THE TIMING/PLACEMENT
OF THESE DISTURBANCES AND ASSOCIATED PRECIP CHANCES THAT NAILING
DOWN MORE SPECIFIC DETAILS...INCREASING OR REMOVING POPS FOR
PARTICULAR LOCATIONS...IS DIFFICULT...BUT AT LEAST THE CHANCES ARE
THERE. FORECAST HIGHS FOR MONDAY REMAIN GENERALLY IN THE LOWER/MID
90S...WITH TUESDAY IN THE MID/UPPER 90S.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
CONCERNS FOR THE TERM PERIOD AGAIN FOCUS ON THUNDERSTORM CHANCES
AND NUMEROUS SHORT WAVE PERTURBATIONS AROUND THE UPPER LEVEL
RIDGE. OTHERWISE NO CHANGES WERE MADE TO THE PREVIOUS FORECAST.
BEGINNING THE LONG TERM PERIOD...THE UPPER LEVEL RIDGE REMAINS
STATIONARY ACROSS PORTIONS OF TEXAS AND OKLAHOMA...FLANKED BY TWO
UPPER LEVEL TROUGHS ON EITHER COAST. THROUGHOUT THE PERIOD...THE
RIDGE SLOWLY BEGINS TO BREAK DOWN AS THE WESTERNMOST TROUGH
CONTINUES TO SHIFT EASTWARD ACROSS CANADA. AS SUCH...THE PEAK OF
THE RIDGE FLATTENS OUT ENOUGH THAT THE PLAINS REMAIN IN PERFECT
POSITION FOR ANY UPPER LEVEL SHORT WAVE THAT PASSES BY. ALTHOUGH
THERE REMAINS MANY DISCREPANCIES ON BOTH UPPER LEVEL FEATURES AND
SURFACE FEATURES AMONG THE LONG TERM MODELS...IT IS BECOMING MORE
AND MORE APPARENT AND SUGGESTED BY THE ALL BLEND MODELS THAT THERE
IS A POSSIBILITY OF AT LEAST SOME PRECIPITATION IN THE LONG TERM.
WHILE IT REMAINS QUITE TOUGH TO PINPOINT EXACTLY WHEN AND WHERE
THESE SHOWERS WILL OCCUR...WAS NOT CONFIDENT ENOUGH TO PULL ALL
POPS COMPLETELY OR LEAVE SLIGHT CHANCES IN EVERY PERIOD AS
SUGGESTED BY ALL BLENDS. PER NEIGHBOR COLLABORATION AND MODELS
INDICATIONS OF THE PRESENCE OF SHORT WAVES AND SURFACE BOUNDARIES
ACROSS THE REGION...CONTINUED WITH SLIGHT CHANCES BOTH WEDNESDAY
AFTERNOON...THURSDAY AND FRIDAY.
REGARDING TEMPERATURES IN THE LONG TERM...EXPECTING WARM
TEMPERATURES TO LAST THROUGH THE PERIOD...ALTHOUGH NOT QUITE HAS
HOT AS PREVIOUS WEEKS...CONTINUED WITH 90S TO NEAR 100 ACROSS
THE AREA. CLOUD COVER AND PRECIPITATION CHANCES COULD CERTAINLY
COME INTO QUESTION AND REDUCE HIGHS JUST SLIGHTLY. ALSO CONFIDENCE
REMAINS LOW FOR TEMPERATURES ON SATURDAY. THE GFS SOLUTION AND THE
ECWMF SOLUTION REMAIN COMPLETELY OPPOSITE EACH OTHER....WITH THE
GFS DRAGGING A COLD FRONT THROUGH THE REGION AND THE ECMWF
SUGGESTS A HIGH OVER THE AREA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ005>007-017>019.
&&
$$
AVIATION/UPDATE...PFANNKUCH
SHORT TERM...ADO
LONG TERM...SALTZMAN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
318 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT ACROSS THE EASTERN CAROLINAS AND VIRGINIA WILL LINGER
AND GRADUALLY DISSIPATE THROUGH TUESDAY. A SERIES OF UPPER LEVEL
DISTURBANCES WILL MOVE SOUTHEASTWARD ACROSS THE REGION ON MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 235 PM SUNDAY...
DIFFUSE COLD FRONT HAS DRIFTED SOUTH SLIGHTLY DURING THE PAST FEW
HOURS WITH NORTHERLY WINDS AT KFAY AND KGSB. DEW POINTS BEHIND THE
FRONT CONTINUE TO FALL TO AROUND 60 IN THE TRIAD WITH MUCH MORE
MOIST DEW POINTS IN THE LOWER 70S ACROSS THE COASTAL PLAIN. MORNING
RAOBS DEPICTED A MUCH DRIER AIR MASS TO THE WEST WITH A PRECIPITABLE
WATER VALUES OF AROUND 0.8/1.1 AT KRNK/KGSO RESPECTIVELY WHILE A PW
OF 1.8 INCHES WAS NOTED AT KMHX. RECENT VISIBLE SATELLITE IMAGERY
DEPICTS A FAIR AMOUNT OF CUMULUS BUT LIMITED VERTICAL GROWTH GIVEN
THE WEAK SUBSIDENCE IN THE WAKE OF A DEPARTING MID LEVEL WAVE AND
DRYING ALOFT.
THE LIMITED THREAT OF CONVECTION THIS AFTERNOON AND EVENING WILL
REMAIN FOCUSED ACROSS THE COASTAL PLAIN...THE SOUTHERN PIEDMONT AND
THE SANDHILLS IN THE VICINITY OF THE SURFACE FRONT...IN A REGION OF
THE DEEPER MOISTURE AND NEAR THE UPPER LEVEL TROUGH AXIS. MOST
CONVECTION ALLOWING MODELS SUGGEST THAT SOME CONVECTION IS POSSIBLE
IN THE EAST TODAY BUT RECENT RUNS OF THE HRRR DOWNPLAY THE COVERAGE
SIGNIFICANTLY. INSTABILITY WILL BE LIMITED TODAY ACROSS THE WEST AND
NORTH WITH MLCAPE VALUES AROUND 500 J/KG...FURTHER EAST IN THE
COASTAL PLAIN MLCAPE VALUES MAY REACH AS HIGH AS 1500 J/KG. MID
LEVEL LAPSE RATES REMAIN RATHER ANEMIC WITH WEAK LOW AND MID LEVEL
FLOW RESULTING IN BULK SHEAR VALUES OF AROUND 15 KTS OR LESS. GIVEN
THE DRY AIR ALOFT...DCAPE VALUES CURRENTLY RANGE AROUND 1300 J/KG
SUGGESTING AT LEAST SOME POTENTIAL FOR STRONG DOWNBURST WINDS WITH A
WELL DEVELOPED CELL. GIVEN THIS ENVIRONMENT...OVERALL STORM STRENGTH
AND ORGANIZATION SHOULD BE LIMITED. PRECIPITATION CHANCES DIMINISH
DURING THE EVENING WITH JUST A LIMITED THREAT OF SHOWERS OR A
THUNDERSTORM OVERNIGHT ACROSS THE EAST AND SOUTH. LOWS TONIGHT
SHOULD DROP INTO THE 67-75 RANGE IN AGREEMENT WITH GUIDANCE. -BLAES
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 310 PM SUNDAY...
A SHORT WAVE TROUGH ACROSS WI/MN/IA ON SUNDAY AFTERNOON ASSOCIATED
WITH A 40 KT MID LEVEL JET WILL DROP SOUTHEAST INTO AND SHARPEN THE
EASTERN U.S. ON MONDAY AN MONDAY NIGHT. THIS FEATURE SHOULD MOVE
ACROSS THE SOUTHERN APPALACHIANS DURING MONDAY AFTERNOON WHICH WILL
SUPPORT THE DEVELOPMENT OF SCATTERED CONVECTION ACROSS THE
CAROLINAS. THE MAIN PUSH OF THE SHORTWAVE WILL MOVE ACROSS GA/SC AND
RESULT IN A SLIGHT COOLING OF TEMPERATURES ALOFT IN CENTRAL NC BUT A
GENERALLY WEAK FLOW ALOFT. THE COLD FRONT DRAPED ACROSS THE
SOUTHEASTERN PORTION OF NC SUNDAY AFTERNOON SHOULD MIGRATE NORTHWEST
EARLY MONDAY AND PROVIDE A FOCUS FOR CONVECTION ACROSS THE EASTERN
PIEDMONT AND COASTAL PAIN. MID LEVEL LAPSE RATES STEEPEN ON MONDAY
AFTERNOON AND MLCAPE VALUES SHOULD RANGE BETWEEN 1000-2000 J/KG
WHILE BULK SHEAR VALUES RANGE AROUND 15 KTS IN CENTRAL NC. PW VALUES
INCREASE SOMEWHAT ON MONDAY AND RANGE FROM 1.4 IN THE TRIAD TO NEAR
2 INCHES IN THE COASTAL PLAIN. THESE PARAMETERS SUGGEST THE
PRIMARY SEVERE WEATHER THREAT ON MONDAY AFTERNOON AND EVENING WILL
BE DAMAGING WINDS FROM WET DOWNBURSTS AND AN ISOLATED MINOR FLOODING
POTENTIAL. LOW LEVEL THICKNESSES WILL CLIMB TO BETWEEN 1410-1420M
MONDAY AFTERNOON...SUGGESTING HIGHS IN THE 88-92 RANGE. SCATTERED
CONVECTION SHOULD PERSIST INTO MONDAY EVENING BUT GENERALLY DIMINISH
OVERNIGHT. LOW TEMPERATURES SHOULD RANGE BETWEEN 68-72 DEGREES.
-BLAES
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 315 PM SUNDAY...
TUESDAY/TUESDAY NIGHT:
THE SYNOPTIC PATTERN OVER THE MID-ATLANTIC/CAROLINAS ON TUE/TUE
NIGHT WILL BE CHARACTERIZED BY TROUGHING ALOFT...ON THE EASTERN
PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL CONUS...
WITH SMALL AMPLITUDE DISTURBANCES PROGRESSING TOWARD THE AREA IN NW
FLOW ALOFT. GIVEN TROUGHING ALOFT IN THE PRESENCE OF A SEASONABLY
MOIST/UNSTABLE AIRMASS...EXPECT ABOVE-NORMAL CHANCES FOR SHOWERS AND
STORMS...PRIMARILY DURING THE AFTERNOON/EVENING HOURS. HOWEVER...THE
TIMING/LOCATION/COVERAGE OF CONVECTION IS STILL UNCERTAIN AND WILL
HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES
EXPECTED TO PROGRESS TOWARD THE REGION IN NW FLOW ALOFT. WITH THE
ABOVE IN MIND...WILL INDICATE A 50% CHANCE OF SHOWERS/STORMS
EVERYWHERE ON TUE...WITH CHANCES DECREASING TO 20% AFTER MIDNIGHT.
HIGHS ON TUE SHOULD BE NEAR NORMAL (UPPER 80S/LOWER 90S) BASED ON
1000-850 MB THICKNESSES IN VICINITY OF 1415 METERS. LOWS WED MORNING
SHOULD ALSO SHOULD BE NEAR NORMAL (UPPER 60S/LOWER 70S). THE PRIMARY
UNCERTAINTY WITH TEMPERATURES WILL BE THE TIMING/LOCATION OF
CONVECTION AND CLOUD COVER ASSOCIATED WITH THE REMNANTS OF
CONVECTION OVER OR UPSTREAM OF THE AREA. AS MENTIONED IN THE SPC DAY
3 CONVECTIVE OUTLOOK...THERE MAY BE AN INCREASED THREAT FOR SEVERE
THUNDERSTORMS TUE AFTERNOON AND EVENING...THOUGH UNCERTAINTY
PERSISTS. MODEL GUIDANCE IS INDICATING RICH BOUNDARY LAYER MOISTURE
TUE AFT/EVE...FOCUSED SHORTWAVE ENERGY DIGGING TOWARD THE AREA IN
VICINITY OF PEAK HEATING...STRENGTHENING MID-UPPER LEVEL FLOW/DEEP
LAYER SHEAR...AND A POTENTIAL FOR MODESTLY STEEP (6-7 C/KM)
MID-LEVEL LAPSE RATES ADVECTING SOUTHEAST TO THE SOUTHERN
APPALACHIANS AND PORTIONS OF THE MID-ATLANTIC/CAROLINAS VIA NW FLOW
ALOFT.
WEDNESDAY THROUGH SUNDAY:
THE SYNOPTIC PATTERN OVER THE CAROLINAS AND MID-ATLANTIC WED-SUN
WILL BE CHARACTERIZED INITIALLY (WED/THU) BY NW FLOW ALOFT...
TRANSITIONING (FRI/SAT/SUN) TO WESTERLY FLOW ALOFT AS THE UPPER
LEVEL RIDGE OVER THE CENTRAL CONUS FLATTENS AND EXTENDS EAST TOWARD
THE CAROLINAS/SOUTHEAST. PRECIPITATION CHANCES...I.E. THE TIMING/
LOCATION/COVERAGE OF CONVECTION...WILL BE HIGHLY DEPENDENT ON THE
EVOLUTION OF SMALL AMPLITUDE DISTURBANCES PROGRESSING SOUTHEAST FROM
THE UPPER MIDWEST/CENTRAL MS RIVER VALLEY INTO THE MID-ATLANTIC AND
CAROLINAS ON WED/THU...WITH A POTENTIAL FOR ENHANCED COVERAGE AND
SEVERE WEATHER. THOUGH UNCERTAINTY INCREASES BY NEXT WEEKEND...
CONVECTION MAY BECOME MORE ISOLATED IN NATURE FRI/SAT/SUN AS THE
MAIN BELT OF WESTERLIES SHIFTS FURTHER NORTH INTO THE MID-ATLANTIC
AND FORCING BECOMES INCREASINGLY CONFINED TO THE PIEDMONT TROUGH/
SEABREEZE...MORE TYPICAL FOR THIS TIME OF YEAR. WILL INDICATE
CHANCES FOR SHOWERS/STORMS SLIGHTLY ABOVE CLIMATOLOGY IN THE 30-40%
RANGE WED/THU...WITH A SLIGHT CHANCE (20%) PERSISTING DURING THE
OVERNIGHT HOURS. ON FRI/SAT/SUN WILL TREND CLOSER TOWARD CLIMATOLOGY
W/REGARD TO CHANCES FOR CONVECTION. TEMPERATURES WILL PRIMARILY
DEPEND ON THE EVOLUTION OF CONVECTION AND ASSOCIATED CLOUD COVER
WED/THU...WITH 1000-850 MB THICKNESSES SUGGESTING HIGHS AND LOWS
NEAR NORMAL...IN THE UPPER 80S TO LOWER 90S AND UPPER 60S TO LOWER
70S. SLIGHTLY ABOVE NORMAL TEMPS (LOWER/MID 90S) WILL BE POSSIBLE
FRI/SAT/SUN GIVEN A RELATIVELY DECREASED POTENTIAL FOR CONVECTION
AND RISING HEIGHTS ALOFT. -VINCENT
&&
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
AS OF 135 PM SUNDAY...
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS CENTRAL NC
THROUGH THE AFTERNOON AND EVENING HOURS WITH LIGHT...MAINLY
NORTHEAST/EASTERLY WINDS. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE ACROSS THE COASTAL PLAIN AND SANDHILLS WHICH COULD IMPACT
KFAY/KRWI. COVERAGE AND CONFIDENCE IS TOO LOW TO INCLUDE A TSRA IN
THE TAF BUT HAVE INCLUDED SHRA AT KFAY WHICH HAS THE GREATEST CHANCE
OF CONVECTION. A STALLED FRONT ACROSS THE COASTAL PLAIN WILL DRIFT
NORTH TONIGHT AND RESULT IN A WIND SHIFT TO SOUTHEAST/SOUTHERLY
WINDS IN THE COASTAL PLAIN AND SANDHILLS WHICH SHOULD RESULT IN
INCREASED LOW LEVEL MOISTURE AND THE DEVELOPMENT OF FOG AND STRATUS.
HAVE HIGHLIGHTED THE POTENTIAL FOR THIS AT KFAY/KRWI WITH IFR/MAYBE
LIFR CONDITIONS POSSIBLE LATE TONIGHT BETWEEN 08-12Z. AFTER MORNING
STRATUS AND FOG...GENERALLY FAIR WEATHER AND VFR CONDITIONS ARE
EXPECTED THROUGH EARLY MONDAY AFTERNOON.
LOOKING BEYOND 18Z MONDAY... SCATTERED THUNDERSTORMS ARE POSSIBLE AT
RDU/RWI/FAY ON MONDAY AFTERNOON/EVENING WITH A PERIOD OF MVFR/IFR
FOG/STRATUS POSSIBLE EARLY TUESDAY MORNING. MORE NUMEROUS
THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON/EVENING. A MORE TYPICAL
THREAT OF SUMMERTIME AFTERNOON/EVENING THUNDERSTORMS AND EARLY
MORNING FOG/STRATUS CONTINUES ON WEDNESDAY AND THURSDAY. -BLAES
&&
.EQUIPMENT...
KRAX...THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...VINCENT
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT ACROSS THE EASTERN CAROLINAS AND VIRGINIA WILL LINGER
AND GRADUALLY DISSIPATE THROUGH TUESDAY. A SERIES OF UPPER LEVEL
DISTURBANCES WILL MOVE SOUTHEASTWARD ACROSS THE REGION ON MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 235 PM SUNDAY...
DIFFUSE COLD FRONT HAS DRIFTED SOUTH SLIGHTLY DURING THE PAST FEW
HOURS WITH NORTHERLY WINDS AT KFAY AND KGSB. DEW POINTS BEHIND THE
FRONT CONTINUE TO FALL TO AROUND 60 IN THE TRIAD WITH MUCH MORE
MOIST DEW POINTS IN THE LOWER 70S ACROSS THE COASTAL PLAIN. MORNING
RAOBS DEPICTED A MUCH DRIER AIR MASS TO THE WEST WITH A PRECIPITABLE
WATER VALUES OF AROUND 0.8/1.1 AT KRNK/KGSO RESPECTIVELY WHILE A PW
OF 1.8 INCHES WAS NOTED AT KMHX. RECENT VISIBLE SATELLITE IMAGERY
DEPICTS A FAIR AMOUNT OF CUMULUS BUT LIMITED VERTICAL GROWTH GIVEN
THE WEAK SUBSIDENCE IN THE WAKE OF A DEPARTING MID LEVEL WAVE AND
DRYING ALOFT.
THE LIMITED THREAT OF CONVECTION THIS AFTERNOON AND EVENING WILL
REMAIN FOCUSED ACROSS THE COASTAL PLAIN...THE SOUTHERN PIEDMONT AND
THE SANDHILLS IN THE VICINITY OF THE SURFACE FRONT...IN A REGION OF
THE DEEPER MOISTURE AND NEAR THE UPPER LEVEL TROUGH AXIS. MOST
CONVECTION ALLOWING MODELS SUGGEST THAT SOME CONVECTION IS POSSIBLE
IN THE EAST TODAY BUT RECENT RUNS OF THE HRRR DOWNPLAY THE COVERAGE
SIGNIFICANTLY. INSTABILITY WILL BE LIMITED TODAY ACROSS THE WEST AND
NORTH WITH MLCAPE VALUES AROUND 500 J/KG...FURTHER EAST IN THE
COASTAL PLAIN MLCAPE VALUES MAY REACH AS HIGH AS 1500 J/KG. MID
LEVEL LAPSE RATES REMAIN RATHER ANEMIC WITH WEAK LOW AND MID LEVEL
FLOW RESULTING IN BULK SHEAR VALUES OF AROUND 15 KTS OR LESS. GIVEN
THE DRY AIR ALOFT...DCAPE VALUES CURRENTLY RANGE AROUND 1300 J/KG
SUGGESTING AT LEAST SOME POTENTIAL FOR STRONG DOWNBURST WINDS WITH A
WELL DEVELOPED CELL. GIVEN THIS ENVIRONMENT...OVERALL STORM STRENGTH
AND ORGANIZATION SHOULD BE LIMITED. PRECIPITATION CHANCES DIMINISH
DURING THE EVENING WITH JUST A LIMITED THREAT OF SHOWERS OR A
THUNDERSTORM OVERNIGHT ACROSS THE EAST AND SOUTH. LOWS TONIGHT
SHOULD DROP INTO THE 67-75 RANGE IN AGREEMENT WITH GUIDANCE. -BLAES
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 310 PM SUNDAY...
A SHORT WAVE TROUGH ACROSS WI/MN/IA ON SUNDAY AFTERNOON ASSOCIATED
WITH A 40 KT MID LEVEL JET WILL DROP SOUTHEAST INTO AND SHARPEN THE
EASTERN U.S. ON MONDAY AN MONDAY NIGHT. THIS FEATURE SHOULD MOVE
ACROSS THE SOUTHERN APPALACHIANS DURING MONDAY AFTERNOON WHICH WILL
SUPPORT THE DEVELOPMENT OF SCATTERED CONVECTION ACROSS THE
CAROLINAS. THE MAIN PUSH OF THE SHORTWAVE WILL MOVE ACROSS GA/SC AND
RESULT IN A SLIGHT COOLING OF TEMPERATURES ALOFT IN CENTRAL NC BUT A
GENERALLY WEAK FLOW ALOFT. THE COLD FRONT DRAPED ACROSS THE
SOUTHEASTERN PORTION OF NC SUNDAY AFTERNOON SHOULD MIGRATE NORTHWEST
EARLY MONDAY AND PROVIDE A FOCUS FOR CONVECTION ACROSS THE EASTERN
PIEDMONT AND COASTAL PAIN. MID LEVEL LAPSE RATES STEEPEN ON MONDAY
AFTERNOON AND MLCAPE VALUES SHOULD RANGE BETWEEN 1000-2000 J/KG
WHILE BULK SHEAR VALUES RANGE AROUND 15 KTS IN CENTRAL NC. PW VALUES
INCREASE SOMEWHAT ON MONDAY AND RANGE FROM 1.4 IN THE TRIAD TO NEAR
2 INCHES IN THE COASTAL PLAIN. THESE PARAMETERS SUGGEST THE
PRIMARY SEVERE WEATHER THREAT ON MONDAY AFTERNOON AND EVENING WILL
BE DAMAGING WINDS FROM WET DOWNBURSTS AND AN ISOLATED MINOR FLOODING
POTENTIAL. LOW LEVEL THICKNESSES WILL CLIMB TO BETWEEN 1410-1420M
MONDAY AFTERNOON...SUGGESTING HIGHS IN THE 88-92 RANGE. SCATTERED
CONVECTION SHOULD PERSIST INTO MONDAY EVENING BUT GENERALLY DIMINISH
OVERNIGHT. LOW TEMPERATURES SHOULD RANGE BETWEEN 68-72 DEGREES.
-BLAES
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN RELATIVELY UNCHANGED
THROUGH THE REMAINDER OF THE WEEK...WITH GENERALLY RIDGING OVER THE
CENTRAL TO WESTERN US AND TROUGHING OVER THE EAST. WHILE NORTHWEST
FLOW WILL CONTINUE ALOFT AND WILL SUPPORT DIURNAL CONVECTION ALONG
THE HIGHER TERRAIN/LEE TROUGH/SEA-BREEZE...IT APPEARS CONVECTION
WILL BE MORE WIDELY SCATTERED. MEDIUM RANGE GUIDANCE
PROJECTS LOW LEVEL THICKNESSES HOLDING NEAR 1425M EACH DAY...WHICH
SHOULD LEAD TO HIGHS IN THE LOWER 90S WITH LOWS CONSISTENTLY IN THE
LOWER 70S.
&&
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
AS OF 135 PM SUNDAY...
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS CENTRAL NC
THROUGH THE AFTERNOON AND EVENING HOURS WITH LIGHT...MAINLY
NORTHEAST/EASTERLY WINDS. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE ACROSS THE COASTAL PLAIN AND SANDHILLS WHICH COULD IMPACT
KFAY/KRWI. COVERAGE AND CONFIDENCE IS TOO LOW TO INCLUDE A TSRA IN
THE TAF BUT HAVE INCLUDED SHRA AT KFAY WHICH HAS THE GREATEST CHANCE
OF CONVECTION. A STALLED FRONT ACROSS THE COASTAL PLAIN WILL DRIFT
NORTH TONIGHT AND RESULT IN A WIND SHIFT TO SOUTHEAST/SOUTHERLY
WINDS IN THE COASTAL PLAIN AND SANDHILLS WHICH SHOULD RESULT IN
INCREASED LOW LEVEL MOISTURE AND THE DEVELOPMENT OF FOG AND STRATUS.
HAVE HIGHLIGHTED THE POTENTIAL FOR THIS AT KFAY/KRWI WITH IFR/MAYBE
LIFR CONDITIONS POSSIBLE LATE TONIGHT BETWEEN 08-12Z. AFTER MORNING
STRATUS AND FOG...GENERALLY FAIR WEATHER AND VFR CONDITIONS ARE
EXPECTED THROUGH EARLY MONDAY AFTERNOON.
LOOKING BEYOND 18Z MONDAY... SCATTERED THUNDERSTORMS ARE POSSIBLE AT
RDU/RWI/FAY ON MONDAY AFTERNOON/EVENING WITH A PERIOD OF MVFR/IFR
FOG/STRATUS POSSIBLE EARLY TUESDAY MORNING. MORE NUMEROUS
THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON/EVENING. A MORE TYPICAL
THREAT OF SUMMERTIME AFTERNOON/EVENING THUNDERSTORMS AND EARLY
MORNING FOG/STRATUS CONTINUES ON WEDNESDAY AND THURSDAY. -BLAES
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...SMITH
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL STALL OUT OVER EASTERN VIRGINIA AND CENTRAL
NORTH CAROLINA TODAY... AND REMAIN THERE THROUGH MONDAY AS IT SLOWLY
WEAKENS AND DISSIPATES. A SERIES OF UPPER LEVEL DISTURBANCES WILL
MOVE SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 235 PM SUNDAY...
DIFFUSE COLD FRONT HAS DRIFTED SOUTH SLIGHTLY DURING THE PAST FEW
HOURS WITH NORTHERLY WINDS AT KFAY AND KGSB. DEW POINTS BEHIND THE
FRONT CONTINUE TO FALL TO AROUND 60 IN THE TRIAD WITH MUCH MORE
MOIST DEW POINTS IN THE LOWER 70S ACROSS THE COASTAL PLAIN. MORNING
RAOBS DEPICTED A MUCH DRIER AIR MASS TO THE WEST WITH A PRECIPITABLE
WATER VALUES OF AROUND 0.8/1.1 AT KRNK/KGSO RESPECTIVELY WHILE A PW
OF 1.8 INCHES WAS NOTED AT KMHX. RECENT VISIBLE SATELLITE IMAGERY
DEPICTS A FAIR AMOUNT OF CUMULUS BUT LIMITED VERTICAL GROWTH GIVEN
THE WEAK SUBSIDENCE IN THE WAKE OF A DEPARTING MID LEVEL WAVE AND
DRYING ALOFT.
THE LIMITED THREAT OF CONVECTION THIS AFTERNOON AND EVENING WILL
REMAIN FOCUSED ACROSS THE COASTAL PLAIN...THE SOUTHERN PIEDMONT AND
THE SANDHILLS IN THE VICINITY OF THE SURFACE FRONT...IN A REGION OF
THE DEEPER MOISTURE AND NEAR THE UPPER LEVEL TROUGH AXIS. MOST
CONVECTION ALLOWING MODELS SUGGEST THAT SOME CONVECTION IS POSSIBLE
IN THE EAST TODAY BUT RECENT RUNS OF THE HRRR DOWNPLAY THE COVERAGE
SIGNIFICANTLY. INSTABILITY WILL BE LIMITED TODAY ACROSS THE WEST AND
NORTH WITH MLCAPE VALUES AROUND 500 J/KG...FURTHER EAST IN THE
COASTAL PLAIN MLCAPE VALUES MAY REACH AS HIGH AS 1500 J/KG. MID
LEVEL LAPSE RATES REMAIN RATHER ANEMIC WITH WEAK LOW AND MID LEVEL
FLOW RESULTING IN BULK SHEAR VALUES OF AROUND 15 KTS OR LESS. GIVEN
THE DRY AIR ALOFT...DCAPE VALUES CURRENTLY RANGE AROUND 1300 J/KG
SUGGESTING AT LEAST SOME POTENTIAL FOR STRONG DOWNBURST WINDS WITH A
WELL DEVELOPED CELL. GIVEN THIS ENVIRONMENT...OVERALL STORM STRENGTH
AND ORGANIZATION SHOULD BE LIMITED. PRECIPITATION CHANCES DIMINISH
DURING THE EVENING WITH JUST A LIMITED THREAT OF SHOWERS OR A
THUNDERSTORM OVERNIGHT ACROSS THE EAST AND SOUTH. LOWS TONIGHT
SHOULD DROP INTO THE 67-75 RANGE IN AGREEMENT WITH GUIDANCE. -BLAES
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...
MONDAY....
WITH THE UPPER RIDGE PARKED OVER THE CENTRAL US...THE UPPER TROUGH
WILL PERSIST OVER THE EASTERN US THIS WEEK...WITH MODELS SHOWING A
PAIR OF DISTURBANCES ON THE NORTHWEST FLOW ALOFT THAT SHOULD AUGMENT
CONVECTIVE POTENTIAL MONDAY AND TUESDAY. THE STALLED OUT FRONTAL
ZONE IN THE VICINITY OF THE EASTERN PIEDMONT AND COASTAL PLAIN
SHOULD BE THE PRIMARY FOCUS FOR CONVECTION ON MONDAY...THOUGH THE
NAM/ECMWF SUGGEST THE BOUNDARY MAY SHIFT BACK WESTWARD AS
SOUTHEASTERLY LOW LEVEL FLOW DEVELOPS IN RESPONSE TO A WEAK 850MB
WAVE DRIFTING NORTHEAST OUT OF SC. DESPITE BACKED SURFACE
WINDS/SHORT CURVED HODOGRAPHS AND MLCAPE VALUES PROJECTED TO REACH
1500 J/KG...THE OVERALL WEAK TROPOSPHERIC FLOW FLOW SHOULD LIMIT THE
SEVERITY OF STORMS MONDAY AFTERNOON. PW VALUES SURGING TO AROUND 2
INCHES SUGGEST THE MAIN THREAT FORM STORMS WOULD BE DAMAGING WINDS
VA PRECIP LOADED AND SOME ISOLATED MINOR FLOODING POTENTIAL.
LOW LEVEL THICKNESSES OF AROUND 1415M ARE FORECAST MONDAY
AFTERNOON... WHICH IS ONLY ABOUT 5M ABOVE NORMAL FOR EARLY AUGUST.
HIGHS 89-92.
MONDAY NIGHT...
A FEW SHOWERS/STORMS COULD PERSIST INTO THE OVERNIGHT HOURS AS
OUTFLOW BOUNDARY LINGER IN THE MOIST AIRMASS...BUT THE COVERAGE OF
CONVECTION SHOULD DECREASE SIGNIFICANTLY AFTER SUNSET. LOWS IN THE
LOWER 70S.
TUESDAY/TUESDAY NIGHT...
CONDITIONS ARE EXPECTED TO AGAIN BE RIPE FOR SCATTERED TO NUMEROUS
STORMS TUESDAY AS MODELS AGREE ON ANOTHER...MORE PRONOUNCED
DISTURBANCE ALOFT DIVING INTO THE BASE OF THE UPPER TROUGH DURING
PEAK HEATING. WITH THE LEE TROUGH EXPECTED TO AGAIN BE THE MAIN LOW
LEVEL FOCUS FOR DEVELOPMENT...STRONG HEATING (HIGHS IN THE LOWER
90S) AND DESTABILIZATION...ALONG WITH SLIGHTLY BETTER DEEP LAYER
SHEAR SUPPORT A BETTER SEVERE THREAT. THERE IS THE POTENTIAL FOR
SHOWERS AND STORMS TO CONTINUE INTO THE OVERNIGHT PERIOD TUESDAY
NIGHT WITH MODELS SHOWING AN 850MB TROUGH PUSHING EAST THROUGH THE
AREA AFTER 00Z AS THE UPPER TROUGH AXIS SHIFTS EAST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN RELATIVELY UNCHANGED
THROUGH THE REMAINDER OF THE WEEK...WITH GENERALLY RIDGING OVER THE
CENTRAL TO WESTERN US AND TROUGHING OVER THE EAST. WHILE NORTHWEST
FLOW WILL CONTINUE ALOFT AND WILL SUPPORT DIURNAL CONVECTION ALONG
THE HIGHER TERRAIN/LEE TROUGH/SEA-BREEZE...IT APPEARS CONVECTION
WILL BE MORE WIDELY SCATTERED. MEDIUM RANGE GUIDANCE
PROJECTS LOW LEVEL THICKNESSES HOLDING NEAR 1425M EACH DAY...WHICH
SHOULD LEAD TO HIGHS IN THE LOWER 90S WITH LOWS CONSISTENTLY IN THE
LOWER 70S.
&&
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
AS OF 135 PM SUNDAY...
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS CENTRAL NC
THROUGH THE AFTERNOON AND EVENING HOURS WITH LIGHT...MAINLY
NORTHEAST/EASTERLY WINDS. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE ACROSS THE COASTAL PLAIN AND SANDHILLS WHICH COULD IMPACT
KFAY/KRWI. COVERAGE AND CONFIDENCE IS TOO LOW TO INCLUDE A TSRA IN
THE TAF BUT HAVE INCLUDED SHRA AT KFAY WHICH HAS THE GREATEST CHANCE
OF CONVECTION. A STALLED FRONT ACROSS THE COASTAL PLAIN WILL DRIFT
NORTH TONIGHT AND RESULT IN A WIND SHIFT TO SOUTHEAST/SOUTHERLY
WINDS IN THE COASTAL PLAIN AND SANDHILLS WHICH SHOULD RESULT IN
INCREASED LOW LEVEL MOISTURE AND THE DEVELOPMENT OF FOG AND STRATUS.
HAVE HIGHLIGHTED THE POTENTIAL FOR THIS AT KFAY/KRWI WITH IFR/MAYBE
LIFR CONDITIONS POSSIBLE LATE TONIGHT BETWEEN 08-12Z. AFTER MORNING
STRATUS AND FOG...GENERALLY FAIR WEATHER AND VFR CONDITIONS ARE
EXPECTED THROUGH EARLY MONDAY AFTERNOON.
LOOKING BEYOND 18Z MONDAY... SCATTERED THUNDERSTORMS ARE POSSIBLE AT
RDU/RWI/FAY ON MONDAY AFTERNOON/EVENING WITH A PERIOD OF MVFR/IFR
FOG/STRATUS POSSIBLE EARLY TUESDAY MORNING. MORE NUMEROUS
THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON/EVENING. A MORE TYPICAL
THREAT OF SUMMERTIME AFTERNOON/EVENING THUNDERSTORMS AND EARLY
MORNING FOG/STRATUS CONTINUES ON WEDNESDAY AND THURSDAY. -BLAES
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BLAES
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...BLAES
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION SECTION
NWS BISMARCK ND
325 PM CDT SUN JUL 29 2012
.SHORT TERM...NOW THROUGH MONDAY NIGHT...
THE FIRST OF WHAT COULD TURN OUT TO BE SEVERAL THUNDERSTORMS
FORMED NEAR BOWMAN THIS AFTERNOON...WHICH IS CONSISTENT WITH THE
16 UTC HRRR AND 12 UTC GFS/NAM...THOUGH A LITTLE WEST OF EXPECTED
INITIATION. THE 12 UTC ECMWF HAS MOVED LIGHT PRECIPITATION
WESTWARD COMPARED TO ITS 00 UTC RUN. FOR THIS REASON...GRIDDED
FORECASTS CONTINUE TO REFLECT HIGHER PRECIPITATION CHANCES AS
FORECAST BY THE 09 UTC SREF. WITH RESPECT TO SEVERITY...SPC HAS
OUTLINED A SLIGHT RISK MAINLY OVER THE DEVILS LAKE BASIN AND
EAST. CONVECTIVE TRENDS SEEM TO JUSTIFY THIS AS THE STORM NEAR
BOWMAN HAS REMAINED NON-SEVERE FOR ALMOST AN HOUR.
THEREAFTER...LOOK FOR PERSISTENCE AS SEVERAL MIDDLE LEVEL
SHORTWAVES MOVE TOWARD THE DAKOTAS. AT PRESENT...MONDAY LOOKS TO
BE DRY...WITH THE NEXT MAIN SYSTEM MOVING INTO THE AREA MONDAY
NIGHT. MODELS ARE A BIT MIXED WITH THE 12 UTC ECMWF DRY AND THE 12
UTC NAM SPOTTY. THE 12 UTC GFS AND 15 UTC SREF MEAN ARE AMONG THE
WET SOLUTIONS...SO MAINTAINED ONLY ISOLATED/SCATTERED ACROSS THE
WEST FOR NOW.
TEMPERATURES WILL REMAIN ABOVE AVERAGE AS THE SUBTROPICAL RIDGE
OVER THE CENTRAL U.S. SHOWS NO SIGN OF WEAKENING.
.LONG TERM...TUESDAY THROUGH SUNDAY...
STRONG RIDGING REMAINS OVER THE PLAINS AND ROCKIES AND EXTENDS WELL
INTO THE CANADIAN PRAIRIE PROVINCES. WEAK SHORTWAVES TOPPING RIDGE
AND DRAGGING WEAK FRONTS ACROSS THE NORTHERN PLAINS WILL TRIGGER
OUTBREAKS OF CONVECTION OVER WESTERN AND CENTRAL NORTH DAKOTA.
THE FIRST SYSTEM ARRIVES IN WESTERN DAKOTAS LATE MONDAY
NIGHT/TUESDAY MORNING AND MOVES ACROSS THE STATE DURING TUESDAY
AFTERNOON AND EVENING.
THE MODELS DIFFER QUITE A BIT ON TIMING WEDNESDAY/THURSDAY BUT WILL
KEEP A MENTION OF PRECIPITATION AT THIS TIME.
BY THURSDAY NIGHT/FRIDAY STRONGER SYSTEM IN NORTHERN FLOW WILL PUSH
STRONG FRONTAL SYSTEM ACROSS THE REGION. THE RIDGE REMAINS OVER THE
SOUTHERN PLAINS BUT IS FLATTENED CONSIDERABLE ALONG THE CANADIAN
BORDER WITH FASTER FLOW. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL
EARLY IN THE EXTENDED THEN DROP TO SLIGHTLY BELOW NORMAL BY NEXT
WEEKEND.
&&
.AVIATION...
THE VCTY OF THE FRONTAL BOUNDARY POSITION WILL BE THE LIKELY AREA
OF TSTM INITIATION THIS AFTN. AT 3 PM CDT...THE POSITION OF THE SFC
FRONT HAD MOVED ONLY SLIGHTLY EASTWARD IN THE PAST COUPLE
OF HOURS...EXTENDING FROM NEAR BOTTINEAU TO BETWEEN KMOT AND
KN60...TO NEAR KBIS AND KHEI. THE BOUNDARY SHOULD MOVE EASTWARD
SLOWLY THIS AFTN AND EVENING. TSTMS HAD DEVELOPED NEAR KHEI ALONG
THE BOUNDARY. KMOT AND KBIS HAVE VCTS BEGINNING AROUND 21Z WITH
THREAT ENDING BY AROUND 00Z...BUT MAY AMEND TO SKC IN THE NEXT HOUR
OR SO IF THREAT OF TSTMS TREND REMAINS TO THE SOUTH AND EAST. KJMS
TAF SITE HAS A CHANCE FOR THUNDER FROM 21Z-03Z. IT APPEARS THAT KISN
AND KDIK MAY BE TOO FAR WEST OF THE BOUNDARY FOR FORECASTING TSTM
DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION....JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
300 PM CDT SUN JUL 29 2012
.SHORT TERM...NOW THROUGH MONDAY NIGHT...
THE FIRST OF WHAT COULD TURN OUT TO BE SEVERAL THUNDERSTORMS
FORMED NEAR BOWMAN THIS AFTERNOON...WHICH IS CONSISTENT WITH THE
16 UTC HRRR AND 12 UTC GFS/NAM...THOUGH A LITTLE WEST OF EXPECTED
INITIATION. THE 12 UTC ECMWF HAS MOVED LIGHT PRECIPITATION
WESTWARD COMPARED TO ITS 00 UTC RUN. FOR THIS REASON...GRIDDED
FORECASTS CONTINUE TO REFLECT HIGHER PRECIPITATION CHANCES AS
FORECAST BY THE 09 UTC SREF. WITH RESPECT TO SEVERITY...SPC HAS
OUTLINED A SLIGHT RISK MAINLY OVER THE DEVILS LAKE BASIN AND
EAST. CONVECTIVE TRENDS SEEM TO JUSTIFY THIS AS THE STORM NEAR
BOWMAN HAS REMAINED NON-SEVERE FOR ALMOST AN HOUR.
THEREAFTER...LOOK FOR PERSISTENCE AS SEVERAL MIDDLE LEVEL
SHORTWAVES MOVE TOWARD THE DAKOTAS. AT PRESENT...MONDAY LOOKS TO
BE DRY...WITH THE NEXT MAIN SYSTEM MOVING INTO THE AREA MONDAY
NIGHT. MODELS ARE A BIT MIXED WITH THE 12 UTC ECMWF DRY AND THE 12
UTC NAM SPOTTY. THE 12 UTC GFS AND 15 UTC SREF MEAN ARE AMONG THE
WET SOLUTIONS...SO MAINTAINED ONLY ISOLATED/SCATTERED ACROSS THE
WEST FOR NOW.
TEMPERATURES WILL REMAIN ABOVE AVERAGE AS THE SUBTROPICAL RIDGE
OVER THE CENTRAL U.S. SHOWS NO SIGN OF WEAKENING.
.LONG TERM...TUESDAY THROUGH SUNDAY...
STRONG RIDGING REMAINS OVER THE PLAINS AND ROCKIES AND EXTENDS WELL
INTO THE CANADIAN PRAIRIE PROVINCES. WEAK SHORTWAVES TOPPING RIDGE
AND DRAGGING WEAK FRONTS ACROSS THE NORTHERN PLAINS WILL TRIGGER
OUTBREAKS OF CONVECTION OVER WESTERN AND CENTRAL NORTH DAKOTA.
THE FIRST SYSTEM ARRIVES IN WESTERN DAKOTAS LATE MONDAY
NIGHT/TUESDAY MORNING AND MOVES ACROSS THE STATE DURING TUESDAY
AFTERNOON AND EVENING.
THE MODELS DIFFER QUITE A BIT ON TIMING WEDNESDAY/THURSDAY BUT WILL
KEEP A MENTION OF PRECIPITATION AT THIS TIME.
BY THURSDAY NIGHT/FRIDAY STRONGER SYSTEM IN NORTHERN FLOW WILL PUSH
STRONG FRONTAL SYSTEM ACROSS THE REGION. THE RIDGE REMAINS OVER THE
SOUTHERN PLAINS BUT IS FLATTENED CONSIDERABLE ALONG THE CANADIAN
BORDER WITH FASTER FLOW. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL
EARLY IN THE EXTENDED THEN DROP TO SLIGHTLY BELOW NORMAL BY NEXT
WEEKEND.
&&
.AVIATION...
THE VCTY OF THE FRONTAL BOUNDARY POSITION WILL BE THE LIKELY AREA
OF TSTM INITIATION THIS AFTN. AT 3 PM CDT...THE POSITION OF THE SFC
FRONT HAD REMAINED NEARLY STATIONARY IN THE PAST COUPLE OF
HOURS...EXTENDING FROM NEAR BOTTINEAU TO BETWEEN KMOT AND KN60...TO
NEAR KHEI. THE BOUNDARY SHOULD MOVE EASTWARD SLOWLY THIS AFTN AND
EVENING. TSTMS HAD DEVELOPED NEAR KHEI ALONG THE BOUNDARY. KMOT AND
KBIS HAVE VCTS BEGINNING AROUND 21Z WITH THREAT ENDING BY AROUND
00Z. KJMS TAF SITE HAS A CHANCE FOR THUNDER FROM 21Z-03Z. IT APPEARS
THAT KISN AND KDIK MAY BE TOO FAR WEST OF THE BOUNDARY FOR
FORECASTING TSTM DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION....JV
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
358 PM EDT SUN JUL 29 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SHIFT EAST-NORTHEAST INTO NEW ENGLAND
TODAY...ALLOWING HIGH PRESSURE OVER THE LOWER GREAT LAKES TO
MOVE INTO CENTRAL PENNSYLVANIA THROUGH TONIGHT. ANOTHER UPPER
LEVEL TROUGH WILL MOVE EAST FROM THE OHIO VALLEY ON MONDAY AND
BECOME NEARLY STATIONARY OVER THE MID-ATLANTIC REGION. THIS
FEATURE WILL MAINTAIN AN UNSETTLED WEATHER PATTERN WITH SEVERAL
OPPORTUNITIES FOR RAIN THROUGH MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
18Z UPDATE...VIS SATL SHOWS CU FIELD HAS GENERALLY DECREASED IN
CVRG WITH MORE SUN THAN CLOUDS AT MOST LOCATIONS. RDR SHOWS
DEVELOPING SHOWERS OVR NRN SCHUYLKILL COUNTY EWD TO ABE VCNTY. THE
LATEST NEAR TERM MODEL GUID CONTINUES TO SHOW A MARGINAL/SLIGHT
INCREASE IN DIURNAL SHOWERS INTO THE MID AFTN WITH AN ISOLD TSTM
PSBL ACRS THE FAR ERN ZONES. RUC DATA ALONG WITH 16Z SATL DERIVED
TPW SHOW A LINGERING MSTR AXIS WITH PWATS BTWN 1-1.5 INCHES OVR
ERN PA. THEREFORE WILL MAINTAIN CHC POPS THRU THE LATE AFTN...WITH
ACTIVITY EXPECTED TO DISSIPATE WITH THE LOSS OF DAYTIME HEATING.
THE SHOWERS/ISOLD TSTMS MAY CONTAIN BRIEF HEAVY DOWNPOURS WITH A
GENERAL 360/15 STM MOTION.
THERE IS ALSO A LINE OF ENHANCED CU DOWNWIND OF LAKE ERIE ASSOC
WITH LAKE BREEZE FNT. INLAND DEWPTS QUICKLY DROP OFF INTO THE 50S
THEREFORE DO NOT EXPECT ISOLD SHOWERS TO REACH THE NW MTNS.
THE MID-UPPER TROUGH AND ASSOCD S/W ENERGY ALONG THE NRN MID-ATLC
- SRN NEW ENG COAST WILL CONTINUE TO LIFT NEWD INTO DOWNEAST MAINE
TONIGHT..ALLOWING SFC HIGH PRES TO OVERSPREAD CENTRAL PA FROM THE
LOWER GREAT LAKES. CLEAR/CALM CONDS AND NEAR TO SLIGHTLY BLW
NORMAL PWS WILL SUPPORT RELATIVELY COOL MINS RANGING FROM THE
LOW-MID 50S NORTH TO LOW-MID 60S SOUTH. SOME OF THE TYPICALLY
COLDER SPOTS IN THE NORTH MAY DIP INTO THE UPPER 40S. THE COOL
AIR...COMBINED WITH LIGHT WINDS AND RELATIVELY WARMER RIVER/STREAM
WATER WILL LIKELY RESULT IN PATCHY LATE NIGHT FOG IN THE DEEP
VALLEYS ACRS THE N-CENTRAL MTNS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
HIGH PRES WILL SHIFT OFF THE NORTHEAST COAST ON MONDAY...ALLOWING
RETURN SOUTHERLY FLOW TO ADVECT HIGHER DEWPTS BACK INTO THE
REGION. LG SCALE FORCING AHEAD OF LOW AMPLITUDE H5 SHORTWAVE TROF
SWEEPING EWD THRU THE OHIO VALLEY...COMBINED WITH WEAK SSELY LLVL
UPSLOPE FLOW AND DIURNAL HEATING WILL LIKELY RESULT IN SCT SHOWERS
AND TSTMS BY AFTN ACROSS THE LAUREL HIGHLANDS/S-CENTRAL MTNS. 00Z
MDL QPFS ARE GENERALLY FAVORING THIS AREA INDICATING A RELATIVE
MAXIMUM FROM THE CUMBERLAND PLATEAU/WV-MD PNHDLS NWD INTO
S-CENTRAL PA.
THE 29/00Z ECMWF IS SHOWING A MOD-HVY QPF AXIS SHIFTING NEWD ACRS
THE AREA TOMORROW NIGHT. THE NCEP GUID ALONG WITH THE 12Z CANADIAN
GENERALLY DO NOT SHOW THIS FEATURE. THERE SHOULD BE A RATHER
ELONGATED/DIFFUSE FNTL BNDRY AROUND WHICH MAY ACT AS A FOCUS FOR
ORGANIZED PCPN...HOWEVER GIVEN THE UNCERTAINTY USED A MEAN BLEND
OF THE OPERATIONAL MODEL AND MOS DATA WHICH RESULTED IN MEDIUM TO
HIGH CHC POPS. ALSO WENT WARMER THAN GUID GIVEN PROSPECTS OF
CLOUDS AND THREAT OF PCPN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
ALL MED RANGE MDL DATA CONTINUES TO INDICATE THE SAME GENERAL
PATTERN OF A DIGGING UPPER LVL TROUGH OVR THE E GRT LKS AND OHIO
VALLEY TUE-WED. THIS SCENARIO WILL PLACE CENTRAL PA IN A
FAVORABLE POSITION FOR DIURNALLY-ENHANCED CONVECTION IN THE MOIST
SOUTHERLY FLOW AHEAD OF TROF. MOST SIGNIFICANT RAINFALL APPEARS
LIKELY ON TUESDAY WITH PASSAGE OF SHORTWAVE ACCOMPANIED BY
ANOMALOUS PWATS IN THE GEFS DATA. HOWEVER...ADDITIONAL SCT
SHRA/TSRA STILL APPEAR LIKELY WED...WHEN ALL MDL INDICATE ANOTHER
SHORTWAVE ROTATES THRU BASE OF EASTERN CONUS TROUGH.
BEST CHANCE FOR A COMPLETELY DRY DAY NEXT WEEK APPEARS TO BE
THURSDAY...AS HIGH PRES RIDGE AND SOMEWHAT DRIER AIR MASS BUILDS
OVR THE AREA. GEFS AND ECMWF ENSEMBLE 8H TEMPS INDICATE TEMPS WILL
BE NEAR SEASONAL NORMS NEXT WEEK. A RETURN TO WARMER...MORE HUMID
CONDS APPEAR LIKELY BY FRI/SAT...AS EASTERN TROUGH LIFTS OUT.
ANOTHER LOW SHOULD MOVE THROUGH PA LATE SUNDAY...EARLY MONDAY.
THIS CURRENTLY LOOKS TO HAVE STRONG UPPER LEVEL SUPPORT.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
29/18Z...SCT-BKN VFR CUMULUS WILL COVER MUCH OF THE CENTRAL AND
ERN AIRSPACE THIS AFTN. AN ISOLD SHRA/TSRA IS POSSIBLE ACRS THE
FAR ERN SXNS NEAR AXIS OF HIGH DEEP LYR MSTR ON BACKSIDE OF
EXITING MID-UPPER TROUGH. EXPECT CVRG TO REMAIN LIMITED AND
THEREFORE WILL NOT MENTION EXPLICITLY IN ERN TERMINALS. KLNS HAS
THE HIGHEST PROBABILITY. THE CU FIELD SHOULD DISSIPATE INTO TNT WITH
THE LOSS OF DAYTIME HEATING...GIVING WAY TO VFR AND M/CLEAR-CALM CONDS
FOR THE OVRNGT PD. SOME AREAS OF FOG ARE POSSIBLE DURING THE PRE-
DAWN HOURS MONDAY BUT SHOULD DISSIPATE BY 13-14Z.
OUTLOOK...
MON...MAINLY VFR. ISOLD-SCT PM TSTM IMPACTS POSSIBLE.
TUE-WED...VFR-MVFR WITH OCNL SHRA AND SCTD TSRA.
THU...FOG POSSIBLE EARLY...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...FITZGERALD/CERU
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
200 PM EDT SUN JUL 29 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SHIFT EAST-NORTHEAST INTO NEW ENGLAND
TODAY...ALLOWING HIGH PRESSURE OVER THE LOWER GREAT LAKES TO
MOVE INTO CENTRAL PENNSYLVANIA THROUGH TONIGHT. ANOTHER UPPER
LEVEL TROUGH WILL MOVE EAST FROM THE OHIO VALLEY ON MONDAY AND
BECOME NEARLY STATIONARY OVER THE MID-ATLANTIC REGION. THIS
FEATURE WILL MAINTAIN AN UNSETTLED WEATHER PATTERN WITH SEVERAL
OPPORTUNITIES FOR RAIN THROUGH MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z UPDATE...VIS SATL SHOWS CU FIELD HAS GENERALLY DECREASED IN
CVRG WITH MORE SUN THAN CLOUDS AT MOST LOCATIONS. RDR SHOWS
DEVELOPING SHOWERS OVR NRN SCHUYLKILL COUNTY EWD TO ABE VCNTY. THE
LATEST NEAR TERM MODEL GUID CONTINUES TO SHOW A MARGINAL/SLIGHT
INCREASE IN DIURNAL SHOWERS INTO THE MID AFTN WITH AN ISOLD TSTM
PSBL ACRS THE FAR ERN ZONES. RUC DATA ALONG WITH 16Z SATL DERIVED
TPW SHOW A LINGERING MSTR AXIS WITH PWATS BTWN 1-1.5 INCHES OVR
ERN PA. THEREFORE WILL MAINTAIN CHC POPS THRU THE LATE AFTN...WITH
ACTIVITY EXPECTED TO DISSIPATE WITH THE LOSS OF DAYTIME HEATING.
THE SHOWERS/ISOLD TSTMS MAY CONTAIN BRIEF HEAVY DOWNPOURS WITH A
GENERAL 360/15 STM MOTION.
THERE IS ALSO A LINE OF ENHANCED CU DOWNWIND OF LAKE ERIE ASSOC
WITH LAKE BREEZE FNT. INLAND DEWPTS QUICKLY DROP OFF INTO THE 50S
THEREFORE DO NOT EXPECT ISOLD SHOWERS TO REACH THE NW MTNS.
THE MID-UPPER TROUGH AND ASSOCD S/W ENERGY ALONG THE NRN MID-ATLC
- SRN NEW ENG COAST WILL CONTINUE TO LIFT NEWD INTO DOWNEAST MAINE
TONIGHT..ALLOWING SFC HIGH PRES TO OVERSPREAD CENTRAL PA FROM THE
LOWER GREAT LAKES. CLEAR/CALM CONDS AND NEAR TO SLIGHTLY BLW
NORMAL PWS WILL SUPPORT RELATIVELY COOL MINS RANGING FROM THE
LOW-MID 50S NORTH TO LOW-MID 60S SOUTH. SOME OF THE TYPICALLY
COLDER SPOTS IN THE NORTH MAY DIP INTO THE UPPER 40S. THE COOL
AIR...COMBINED WITH LIGHT WINDS AND RELATIVELY WARMER RIVER/STREAM
WATER WILL LIKELY RESULT IN PATCHY LATE NIGHT FOG IN THE DEEP
VALLEYS ACRS THE N-CENTRAL MTNS.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
HIGH PRES WILL SHIFT OFF THE NORTHEAST COAST ON MONDAY...ALLOWING
RETURN SOUTHERLY FLOW TO ADVECT HIGHER DEWPTS BACK INTO THE
REGION. LG SCALE FORCING AHEAD OF LOW AMPLITUDE H5 SHORTWAVE TROF
SWEEPING EWD THRU THE OHIO VALLEY...COMBINED WITH WEAK SSELY LLVL
UPSLOPE FLOW AND DIURNAL HEATING WILL LIKELY RESULT IN SCT SHOWERS
AND TSTMS BY AFTN ACROSS THE LAUREL HIGHLANDS/S-CENTRAL MTNS. 00Z
MDL QPFS ARE GENERALLY FAVORING THIS AREA INDICATING A RELATIVE
MAXIMUM FROM THE CUMBERLAND PLATEAU/WV-MD PNHDLS NWD INTO
S-CENTRAL PA.
THE 29/00Z ECMWF IS SHOWING A MOD-HVY QPF AXIS SHIFTING NEWD ACRS
THE AREA TOMORROW NIGHT. THE NCEP GUID ALONG WITH THE 12Z CANADIAN
GENERALLY DO NOT SHOW THIS FEATURE. THERE SHOULD BE A RATHER
ELONGATED/DIFFUSE FNTL BNDRY AROUND WHICH MAY ACT AS A FOCUS FOR
ORGANIZED PCPN...HOWEVER GIVEN THE UNCERTAINTY USED A MEAN BLEND
OF THE OPERATIONAL MODEL AND MOS DATA WHICH RESULTED IN MEDIUM TO
HIGH CHC POPS. ALSO WENT WARMER THAN GUID GIVEN PROSPECTS OF
CLOUDS AND THREAT OF PCPN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
ALL MED RANGE MDL DATA CONTINUES TO INDICATE THE SAME GENERAL
PATTERN OF A DIGGING UPPER LVL TROUGH OVR THE E GRT LKS AND OHIO
VALLEY TUE-WED. THIS SCENARIO WILL PLACE CENTRAL PA IN A
FAVORABLE POSITION FOR DIURNALLY-ENHANCED CONVECTION IN THE MOIST
SOUTHERLY FLOW AHEAD OF TROF. MOST SIGNIFICANT RAINFALL APPEARS
LIKELY ON TUESDAY WITH PASSAGE OF SHORTWAVE ACCOMPANIED BY
ANOMALOUS PWATS IN THE GEFS DATA. HOWEVER...ADDITIONAL SCT
SHRA/TSRA STILL APPEAR LIKELY WED...WHEN ALL MDL INDICATE ANOTHER
SHORTWAVE ROTATES THRU BASE OF EASTERN CONUS TROUGH.
BEST CHANCE FOR A COMPLETELY DRY DAY NEXT WEEK APPEARS TO BE
THURSDAY...AS HIGH PRES RIDGE AND SOMEWHAT DRIER AIR MASS BUILDS
OVR THE AREA. GEFS AND ECMWF ENSEMBLE 8H TEMPS INDICATE TEMPS WILL
BE NEAR SEASONAL NORMS NEXT WEEK. A RETURN TO WARMER...MORE HUMID
CONDS APPEAR LIKELY BY FRI/SAT...AS EASTERN TROUGH LIFTS OUT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
29/18Z...SCT-BKN VFR CUMULUS WILL COVER MUCH OF THE CENTRAL AND
ERN AIRSPACE THIS AFTN. AN ISOLD SHRA/TSRA IS POSSIBLE ACRS THE
FAR ERN SXNS NEAR AXIS OF HIGH DEEP LYR MSTR ON BACKSIDE OF
EXITING MID-UPPER TROUGH. EXPECT CVRG TO REMAIN LIMITED AND
THEREFORE WILL NOT MENTION EXPLICITLY IN ERN TERMINALS. KLNS HAS
THE HIGHEST PROBABILITY. THE CU FIELD SHOULD DISSIPATE INTO TNT WITH
THE LOSS OF DAYTIME HEATING...GIVING WAY TO VFR AND M/CLEAR-CALM CONDS
FOR THE OVRNGT PD. SOME AREAS OF FOG ARE POSSIBLE DURING THE PRE-
DAWN HOURS MONDAY BUT SHOULD DISSIPATE BY 13-14Z.
OUTLOOK...
MON...MAINLY VFR. ISOLD-SCT PM TSTM IMPACTS POSSIBLE.
TUE-WED...VFR-MVFR WITH OCNL SHRA AND SCTD TSRA.
THU...FOG POSSIBLE EARLY...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...FITZGERALD
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
529 PM CDT SUN JUL 29 2012
.UPDATE...
SENDING OUT A QUICK UPDATE TO EXTEND SLIGHT CHANCE POPS FURTHER
EASTWARD BASED ON LATEST RADAR TRENDS. AREA OF LIGHT RAIN MOVING
SOUTHEASTWARD CONTINUES TO WEAKEN AND SHRINK IN SIZE...BUT PRECIP
IS NEVERTHELESS MAKING IT FURTHER EASTWARD THAN CURRENT
GRIDS/ZONES INDICATE. REST OF FORECAST IS UNCHANGED.
&&
.PREV DISCUSSION... /ISSUED 305 PM CDT SUN JUL 29 2012/
DISCUSSION...TEMPS WERE A LITTLE LOWER THIS AFTN COMPARED TO
SATURDAY IN THE WAKE OF YESTERDAY/S WEAK FRONT PLUS THE CLOUD
COVER THAT HAS BEEN INCREASING FROM THE NORTHWEST TODAY. AN AREA
OF SHOWERS HAS BEEN APPROACHING MID TN FROM THE NORTHWEST ALL DAY
AND HAS REFUSED TO WEAKEN. SOME LIGHT RETURNS ON 88D WERE NOTED IN
NW COUNTIES AT 19Z. HRRR SEEMS TO BE HANDLING THIS PRECIP BETTER
THE PAST COUPLE HOURS...AND IT SHOWS THE AREA GRADUALLY WEAKENING
AS IT MOVES THROUGH WEST MIDDLE TN DURING NEXT SEVERAL HOURS BEFORE
DISSIPATING BEFORE 00Z.
FOR THE WEEK AHEAD...MODELS AGREE THAT NORTHWEST FLOW WILL
CONTINUE ALOFT THROUGH MOST OF THE WEEK AS H5 RIDGE...CENTERED
OVER WESTERN OKLAHOMA AT 12Z TODAY...STAYS IN THE VCNTY OF THE TX
PANHANDLE THROUGH AT LEAST THURSDAY. THIS PATTERN LEAVES TN
VULNERABLE TO WEAK SHORT WAVES APPROACHING FROM THE NW...
ESPECIALLY OVER THE NEXT COUPLE DAYS.
THE NEXT S/W TO APPROACH US WAS OVER SOUTHERN MN AT 12Z. MODELS
ARE INCONSISTENT IN HANDLING PRECIP FROM THIS S/W AS WELL AS THE
NEXT ONE. THE NAM HITS THE FIRST ONE HARDER LATE TONIGHT AND
MONDAY...WHILE THE GFS HITS THE SECOND ONE HARDER ON MONDAY NIGHT
AND TUESDAY. CANNOT HAVE CONFIDENCE IN MODEL TIMING EITHER OF
THESE WAVES BUT 20 TO 30 POPS ARE CERTAINLY WARRANTED AREA WIDE FOR
MOST OF THE WEEK. CONVECTION MAY BE MINIMIZED ON WEDNESDAY AS
MODELS SHOW LOWER MEAN HUMIDITY BEHIND THE SECOND S/W.
BY FRIDAY AND NEXT WEEKEND...THE H5 RIDGE ELONGATES ACROSS THE
WHOLE SOUTHERN U.S. AND ENDS OUR NW FLOW PATTERN. THUS...NORMAL
SUMMER DIURNAL CONVECTION EXPECTED WITH 20 TO 30 PERCENT CHANCE OF
AFTN/EVENING STORMS. TEMPS WILL CONTINUE ABOVE SEASONAL NORMS
WITH HIGHS IN 90S AND LOWS IN 70S EXCEPT A FEW DEGREES LOWER ON
THE PLATEAU.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
305 PM CDT SUN JUL 29 2012
.DISCUSSION...TEMPS WERE A LITTLE LOWER THIS AFTN COMPARED TO
SATURDAY IN THE WAKE OF YESTERDAY/S WEAK FRONT PLUS THE CLOUD
COVER THAT HAS BEEN INCREASING FROM THE NORTHWEST TODAY. AN AREA
OF SHOWERS HAS BEEN APPROACHING MID TN FROM THE NORTHWEST ALL DAY
AND HAS REFUSED TO WEAKEN. SOME LIGHT RETURNS ON 88D WERE NOTED IN
NW COUNTIES AT 19Z. HRRR SEEMS TO BE HANDLING THIS PRECIP BETTER
THE PAST COUPLE HOURS...AND IT SHOWS THE AREA GRADUALLY WEAKENING
AS IT MOVES THROUGH WEST MIDDLE TN DURING NEXT SEVERAL HOURS BEFORE
DISSIPATING BEFORE 00Z.
FOR THE WEEK AHEAD...MODELS AGREE THAT NORTHWEST FLOW WILL
CONTINUE ALOFT THROUGH MOST OF THE WEEK AS H5 RIDGE...CENTERED
OVER WESTERN OKLAHOMA AT 12Z TODAY...STAYS IN THE VCNTY OF THE TX
PANHANDLE THROUGH AT LEAST THURSDAY. THIS PATTERN LEAVES TN
VULNERABLE TO WEAK SHORT WAVES APPROACHING FROM THE NW...
ESPECIALLY OVER THE NEXT COUPLE DAYS.
THE NEXT S/W TO APPROACH US WAS OVER SOUTHERN MN AT 12Z. MODELS
ARE INCONSISTENT IN HANDLING PRECIP FROM THIS S/W AS WELL AS THE
NEXT ONE. THE NAM HITS THE FIRST ONE HARDER LATE TONIGHT AND
MONDAY...WHILE THE GFS HITS THE SECOND ONE HARDER ON MONDAY NIGHT
AND TUESDAY. CANNOT HAVE CONFIDENCE IN MODEL TIMING EITHER OF
THESE WAVES BUT 20 TO 30 POPS ARE CERTAINLY WARRANTED AREA WIDE FOR
MOST OF THE WEEK. CONVECTION MAY BE MINIMIZED ON WEDNESDAY AS
MODELS SHOW LOWER MEAN HUMIDITY BEHIND THE SECOND S/W.
BY FRIDAY AND NEXT WEEKEND...THE H5 RIDGE ELONGATES ACROSS THE
WHOLE SOUTHERN U.S. AND ENDS OUR NW FLOW PATTERN. THUS...NORMAL
SUMMER DIURNAL CONVECTION EXPECTED WITH 20 TO 30 PERCENT CHANCE OF
AFTN/EVENING STORMS. TEMPS WILL CONTINUE ABOVE SEASONAL NORMS
WITH HIGHS IN 90S AND LOWS IN 70S EXCEPT A FEW DEGREES LOWER ON
THE PLATEAU.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 68 95 74 95 / 20 20 30 30
CLARKSVILLE 66 93 72 94 / 30 20 30 30
CROSSVILLE 61 87 68 86 / 10 20 30 50
COLUMBIA 68 96 74 96 / 20 20 30 40
LAWRENCEBURG 67 95 73 96 / 20 20 30 30
WAVERLY 68 94 73 95 / 30 20 30 30
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
49