Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/28/12
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1018 PM EDT FRI JUL 27 2012
.UPDATE...
CURRENT RADAR TREND SHOWS THE STRONG TSTMS THAT MOVED THROUGH CSG
AROUND 800 PM EDT ARE WEAKENING AND MOVING INTO SOUTHWEST GA.
OTHERWISE...THE AIRMASS OVER NORTH AND CENTRAL GA CONTINUES TO
STABILIZE. ONLY SCATTERED SPRINKLES OF LIGHT RAIN FROM MID LEVEL
MOISTURE FROM DISSIPATING TSTMS WAS OCCURRING OVER PORTIONS OF NORTH
GA. EXPECT ALL PRECIPITATION TO DIMINISH JUST AFTER MIDNIGHT. HAVE
LOWERED POPS ACCORDINGLY. PATCHY FOG WILL DEVELOP LATE TONIGHT
THROUGH SUNRISE IN AREAS WHERE MEASURABLE RAIN OCCURRED EARLIER
TODAY. OTHERWISE...NO OTHER CHANGES NEEDED AS FORECAST MIN TEMPS
ARE ON TRACK.
16
&&
.PREV DISCUSSION... /ISSUED 800 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 HYDROMETER 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
AVIATION...
00Z UPDATE...
RADARS SHOW TSTMS MOVING THROUGH CSG AT THIS TIME. EXPECT THE
AIRMASS OVER GA TO STABILIZE QUICKLY THIS EVENING WITH MOSTLY VFR
CONDITIONS EXPECTED. HAVE NOT PUT IN THE TAFS...BUT PATCHY FOG CAN
BE EXPECTED IN THE MORNING WHERE SIGNIFICANT MEASURABLE RAIN
OCCURRED TODAY. VSBYS MAY BE REDUCED IN THE 3 TO 4 MILE RANGE.
OTHERWISE...LOOKING FOR ANOTHER ROUND OF SCATTERED TSTMS ON
SATURDAY AFTERNOON. WINDS GENERALLY LIGHT AND FROM THE WEST TO
NORTHWEST THROUGH THE FORECAST PERIOD. AN OUTFLOW BOUNDARY WILL
TEMPORARY AFFECT ATL THROUGH 01Z THIS EVENING WITH A SOUTH TO
SOUTHWEST WIND.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON ALL ELEMENTS.
16
&&
.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 / 30 30 10 20
CARTERSVILLE 71 93 70 92 / 30 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...
NONE.
&&
$$
SHORT TERM...16
LONG TERM....37
AVIATION...16
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
800 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 HYDROMETER 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...
00Z UPDATE...
RADARS SHOW TSTMS MOVING THROUGH CSG AT THIS TIME. EXPECT THE
AIRMASS OVER GA TO STABILIZE QUICKLY THIS EVENING WITH MOSTLY VFR
CONDITIONS EXPECTED. HAVE NOT PUT IN THE TAFS...BUT PATCHY FOG CAN
BE EXPECTED IN THE MORNING WHERE SIGNIFICANT MEASURABLE RAIN
OCCURRED TODAY. VSBYS MAY BE REDUCED IN THE 3 TO 4 MILE RANGE.
OTHERWISE...LOOKING FOR ANOTHER ROUND OF SCATTERED TSTMS ON SATURDAY
AFTERNOON. WINDS GENERALLY LIGHT AND FROM THE WEST TO NORTHWEST
THROUGH THE FORECAST PERIOD. AN OUTFLOW BOUNDARY WILL TEMPORARY
AFFECT ATL THROUGH 01Z THIS EVENING WITH A SOUTH TO SOUTHWEST WIND.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON ALL ELEMENTS.
16
&&
.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...16
LONG TERM....GOODEN
AVIATION...16
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
154 AM EDT THU JUL 26 2012
.UPDATE...
WILL BE ISSUING A HEAT ADVISORY FOR MUCH OF MIDDLE AND EASTCENTRAL
GA FOR LATE THIS MORNING THROUGH MID EVENING. MORE DISCUSSION WILL
FOLLOW.
SNELSON
.PREV DISCUSSION... /ISSUED 948 PM EDT WED JUL 25 2012/
UPDATE...
ONLY A FEW SHOWERS LINGER AROUND THE CSG AREA AND WILL THEREFORE
REMOVE ALL POPS EXCEPT FOR CSG AREA AND TAKE OUT ALL THUNDER. NO
OTHER CHANGES PLANNED.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
/ISSUED AT 337 PM EDT WED JUL 25 2012/
MAIN FORECAST CONCERN IS HEAT TODAY AND THURSDAY ALONG WITH
CONVECTION DEVELOPMENT BOTH AFTERNOONS. CURRENT TEMPS HAVE BEEN
RIGHT ON TRACK WITH FORECAST AND AREAS IN THE SOUTH ARE IN LINE FOR
REACHING HEAT ADVISORY CRITERIA...THEREFORE WILL CONTINUE CURRENT
PRODUCT. GENERALLY WENT WITH BLEND OF MAV AND MET SOLUTIONS FOR
TEMPS INTO TOMORROW NIGHT. AREAS IN THE EAST CENTRAL AND SOUTHEAST
PORTIONS LOOK TO AGAIN REACH OVERNIGHT MIN TEMPS OF AT LEAST 75
DEGREES AND PEAK HEAT INDICES OF AT LEAST 105 DEGREES TOMORROW. FOR
850 MB TEMPS...THE GFS HAS SIMILAR VALUES TO SLIGHTLY WARMER FOR
THURSDAY AFTERNOON WHILE THE NAM GOES SLIGHTLY COOLER PARTICULARLY
IN THE SOUTHWEST PORTION. THIS IS LIKELY DUE TO A SLUG OF TROPICAL
MOISTURE AND ASSOCIATED CLOUD COVER PROGGED TO ADVECT NORTHWARD INTO
THE AREA FROM THE NE GULF COAST. ATTM IT APPEARS THAT EXTENDING THE
CURRENT HEAT ADVISORY INTO THURSDAY EARLY EVENING FOR THE EAST
CENTRAL AND SOUTHEAST PORTIONS WOULD BE REASONABLE WITH PERHAPS
TRIMMING OUT THE SOUTHWEST. THIS DECISION WILL BE BEST MADE LATER
THIS AFTERNOON INTO EARLY EVENING SO AS TO PREVENT CONFUSION WITH
CURRENT PRODUCT... THEREFORE PLEASE STAY TUNED TO FUTURE UPDATES.
THE OUTFLOW FROM MCS REMNANTS ACROSS THE CAROLINAS EARLIER TODAY HAS
SERVED MOSTLY TO STABILIZE THE ENVIRONMENT ACROSS THE EASTERN
PORTION OF THE AREA. THE SOUTHERN AND WESTERN PERIPHERIES OF THIS
FEATURE MAY FOCUS DEVELOPMENT LATER TODAY...HOWEVER THE HRRR DOES
NOT BUY INTO THIS MUCH AND JUST HAS THE MAIN DEVELOPMENT IN THE
SOUTHWEST. CURRENT VIS SATELLITE IMAGERY HAS SHOWN SOME CU FIELD
ENHANCEMENTS WITH THE ASSOCIATED OUTFLOW AND PERHAPS WEAK GRAVITY
WAVES... BUT EARLY SHOWER AND THUNDERSTORM DEVELOPMENT HAS BEEN
CLOSER TO THE SW PORTION OF THE AREA. HAVE THEREFORE GONE WITH
HIGHER CHANCE POPS IN THE SW TAPERING TO SLIGHT POPS IN THE NW.
MLCAPE VALUES OF 2500-3500 J/KG...WEAK VERTICAL WIND SHEAR...AND PW
VALUES OF 1.8-2.0 INCHES WILL ALLOW FOR THE MAIN STORM THREATS BEING
STRONG WINDS...HEAVY RAINFALL...FREQUENT LIGHTNING...AND SMALL HAIL.
ISOLATED SEVERE STORMS ARE POSSIBLE AS WELL... ESPECIALLY IN THE
SOUTHWEST WHERE SPC ALSO HAS A SLIGHT RISK ISSUED.
WITH THE UPPER RIDGE AXIS OVER THE GREAT LAKES PROGGED TO DAMPEN OUT
AND BREAK DOWN...THE ASSOCIATED NW FLOW ALOFT EXTENDING INTO THE
CAROLINAS SHOULD WEAKEN AND BECOME MORE ZONAL BY 12Z THURSDAY. THE
COMBINATION OF A WEAK LEE SFC TROUGH AND ENHANCED MOISTURE FROM THE
ADVECTION OF THE AFOREMENTIONED TROPICAL PLUME IN THE NE GULF WILL
ALLOW FOR THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN IN THE
SOUTH ON THURSDAY. GUIDANCE IS IN GOOD AGREEMENT WITH A DEVELOPING
UPPER TROUGH APPROACHING THE NORTHERN PORTION OF THE AREA BY LATE
THURSDAY NIGHT...ALONG WITH AN ASSOCIATED SFC FRONT. THIS MAY
INCREASE PRECIP POTENTIAL IN THE NORTHERN PORTION THURSDAY NIGHT
INTO FRIDAY.
03
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
/ISSUED AT 337 PM EDT WED JUL 25 2012/
HAVE MADE NO CHANGES TO THE LONG TERM. MODELS CONSISTED IN SHOWING
A FRONTAL BOUNDARY SINKING INTO THE CWA SATURDAY INTO SUNDAY.
NORTH GA MAY BE DRY SATURDAY NIGHT INTO SUNDAY NIGHT BUT MOISTURE
RETURNS BY THE FIRST OF THE WEEK.
41
PREVIOUS DISCUSSION/ISSUED 421 AM WED JUL 25 2012/
HIGH PRESSURE RIDGE OVER THE AREA WEAKENS AND SINKS SOUTH IN THE
SHORT TERM. BY FRI...THE RIDGE AXIS IS OVER FL AND THE GULF AND AN
APPROACHING COLD FRONT IS MOVING SOUTH OUT OF THE UPPER MS RIVER
VALLEY. THIS RIDGE STILL DOMINATES THE WEATHER PATTERN THROUGH THE
END OF THE WORK WEEK KEEPING NORTH AND CENTRAL GA IN MOIST WEST TO
SOUTHWESTERLY FLOW. PRECIPITABLE WATER VALUES STILL SHOWING NEAR
1.5 TO 1.8 INCH SO HEAVY RAIN WILL STILL BE A CONCERN...AT LEAST
THROUGH FRI. DIURNALLY DRIVEN THUNDERSTORMS WILL CONTINUE THROUGH
FRIDAY...BUT THEN THINGS BEGIN TO CHANGE SAT. A DEEP CLOSED LOW
CENTER TRACKS EAST ACROSS THE GREAT LAKES STATES AND INTO THE NEW
ENGLAND STATES THU...WITH ITS ASSOCIATED COLD FRONT MOVING
SOUTHWARD. THIS FRONT MOVES INTO NORTH GA BY 00Z SAT AND CONTINUES
MOVING SOUTHWARD INTO NORTH FL BY 12Z-18Z SUN. THIS FRONT BRINGS
IN A MUCH DRIER AIRMASS AND COOLER TEMPS FOR THE STATE SUN. HAVE
BACKED OFF ON POPS FOR SUN TO JUST ISOLATED TSRA MAINLY FOR
CENTRAL GA. MOISTURE DOES INCREASE AGAIN MON/TUE SO WILL KEEP
ISO/SCT SHRA/TSRA BACK IN THE FORECAST MON/TUE.
01
CLIMATE...
RECORDS FOR 07-26
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 103 2010 80 1904 76 2005 56 1911
1936
KATL 98 1901 78 1890 77 2005 59 1911
KCSG 99 2010 82 1954 79 1983 66 1948
KMCN 100 2010 80 1957 78 2005 60 1911
1993
&&
.AVIATION...
06Z UPDATE...
MAIN CONCERN TODAY WILL BE EXPECTED COVERAGE OF TSRA. SIMILAR
PATTERN TODAY AS YESTERDAY. EXPECT TSRA TO DEVELOP AROUND 19-20Z
OVER SRN GA AND DRIFT NORTH. BETTER CHC AGAIN IN MIDDLE AND
WESTCENTRAL GA THAN IN THE NORTH. COVERAGE OF TSRA AGAIN WILL
BE AROUND 30 PCT...WILL CONTINUE PROB30 AT ALL AIRPORTS BUT MAY
NEED TEMPO AT KCSG ADN POSSIBLY KMCN IF CONFIDENCE CONTINUES TO
INCREASE. NW WINDS WILL SHIFT TO SW AT MOST AIRPORTS AROUND
18-19Z. MAY SEE ONE OR TWO HOURS OF GUSTS TO AROUND 20KTS IN THE
AFTERNOON...ESP AT KATL.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON TSRA LIKELIHOOD.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 98 74 98 73 / 20 20 30 20
ATLANTA 96 75 94 74 / 30 20 40 20
BLAIRSVILLE 91 69 90 68 / 20 20 50 40
CARTERSVILLE 96 73 94 69 / 20 20 50 30
COLUMBUS 95 75 93 76 / 40 30 40 20
GAINESVILLE 93 74 94 73 / 20 20 40 30
MACON 96 74 97 74 / 40 30 30 20
ROME 97 73 94 69 / 20 20 50 30
PEACHTREE CITY 95 73 94 70 / 30 20 40 20
VIDALIA 100 77 97 77 / 30 20 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....01
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1044 AM CDT THU JUL 26 2012
.DISCUSSION...
ISSUED 1044 AM CDT THU JUL 26 2012
OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION CLEARED THE FORECAST
AREA TO THE SOUTHEAST...WITH WINDS AT LEAST BRIEFLY SHIFTING TO
THE NORTHWEST. HOWEVER...THE FURTHER SOUTHEAST YOU GO...THE LESS
IMPACT THIS OUTFLOW HAS HAD ON TEMPERATURES. TEMPERATURES IN THE
NORTHWEST PORTION OF THE FORECAST AREA ARE IN THE 70S...WHILE
TEMPERATURES HAVE CLIMBED INTO THE 90S IN THE SOUTHEAST. FAIRLY
EXTENSIVE CLOUD COVER ASSOCIATED WITH THE EARLIER CONVECTION
EXTENDS FROM THE GREAT LAKES INTO THE SOUTHERN PLAINS IN
ALONG/AHEAD OF A SLOWLY ADVANCING COLD FRONT.
MAIN CONCERN TODAY IS HOW MUCH THE ATMOSPHERE CAN RECOVER IN THE
WAKE OF THE EARLIER OUTFLOW. SPC MESOANALYSIS SHOWS PRETTY STOUT
CAPPING STILL IN PLACE FOR SURFACE BASED CONVECTION...AND WE MAY
HAVE TROUBLE ERODING THIS CAP DUE TO THE EXPANSIVE CLOUD COVER
THAT DOES NOT APPEAR TO BE GOING ANYWHERE QUICKLY. THE BEST CHANCE
FOR STORM DEVELOPMENT REMAINS IN THE SOUTHEAST HALF OF THE
FORECAST AREA WHERE TEMPERATURES WERE NOT IMPACTED AS MUCH AS
FURTHER TO THE NORTHWEST.
WILL UPDATE FORECAST TO LOWER POPS FOR MOST OF THE FORECAST
AREA...DUE TO THE CAPPING AND LIMITED TIME FOR RECOVERY DUE TO THE
CLOUD COVER. HAVE ALSO MADE TWEAKS TO MOST OTHER PARAMETERS FOR
THE LATEST TRENDS.
BAK
&&
.AVIATION...
ISSUED 655 AM CDT THU JUL 26 2012
FORECAST COMPLICATIONS ARE MULTIPLE BOUNDARIES...OUTFLOWS...AND
SCT PRECIP ON SAT IMAGERY FALLING APART AS IT RUNS INTO DRY AIR
OVER CENTRAL ILLINOIS. CONFIDENCE IN ANY MODEL SOLUTION FOR PRECIP
IS MINIMAL AS MOST OF THEM ARE COMING IN TOO WET. REFIRE OF ANY
MESO OR SYNOPTIC SCALE BOUNDARIES THROUGH THE AFTERNOON IS ALLUDED
TO...BUT NOTHING HAS HIGH ENOUGH CONFIDENCE TO GO WITH IT JUST
YET. SO FORECAST REMAINS AN ISSUE OF WINDS FROM SW TO NW...AND MID
LEVEL CLOUDS. SOME CU DEVELOPMENT EXPECTED UNDER THE AC AS WELL.
HJS
&&
.PREV DISCUSSION...
ISSUED 315 AM CDT THU JUL 26 2012
SERIES OF MCS SYSTEMS LINED UP FROM KANSAS TO LOWER MICHIGAN HAS
BEEN WEAKENING THE LAST COUPLE HOURS. HAVE MANAGED TO GET A FEW
STORMS FIRING IN THE ILLINOIS DESERT ALONG AN OUTFLOW BOUNDARY...
WHICH STRETCHED FROM PITTSFIELD TO PONTIAC AT 2 AM. SOME GUSTS TO
35-40 MPH OCCURRED ALONG THIS BOUNDARY...WITH HIGHER SPEEDS IN
NORTHERN ILLINOIS. HOWEVER...MUCH OF THE LARGER RAIN SHIELD HAS
BEEN DIMINISHING AS IT APPROACHES WEST CENTRAL ILLINOIS. THE
PRIMARY COLD FRONT EXTENDED FROM THE TEXAS PANHANDLE TO LOWER
MICHIGAN...WITH A SECONDARY BOUNDARY FROM NORTHWEST KANSAS TO THE
MINNESOTA ARROWHEAD.
SHORT TERM...TODAY THROUGH SATURDAY...
PRIMARY FORECAST CONCERN DURING THIS PERIOD INVOLVES CONVECTIVE
REDEVELOPMENT TODAY. LATEST HRRR MODEL SHOWS A WEAKENING TREND
CONTINUING WITH THE EXISTING CONVECTION AS IT MOVES THROUGH
ILLINOIS. ADDITIONAL DEVELOPMENT SHOULD START FIRING TOWARD MIDDAY
AS THE MAIN COLD FRONT APPROACHES SOUTHEAST ILLINOIS TOWARD EARLY
AFTERNOON. ENTIRE CWA IS UNDER A SLIGHT RISK OF SEVERE WEATHER FOR
TODAY...HOWEVER THE BETTER CHANCES WILL BE CLOSER TO THE I-70
CORRIDOR AHEAD OF THE FRONT...WHERE THE ATMOSPHERE WILL BE LESS
OVERTURNED BY THE EARLY MORNING CONVECTION. LATEST NAM MODEL
PROJECTS 3000 J/KG OF CAPE IN THIS AREA BY THE TIME THE FRONT
ARRIVES. MOST OF THE RAIN SHOULD BE OUT OF THE AREA BY EARLY
EVENING...BUT WILL LINGER SOME SMALL POPS EAST OF I-57 INTO
EVENING. SOME ADDITIONAL SHOWERS AND STORMS WILL OCCUR OVER
PORTIONS OF THE MIDWEST FRIDAY...AS THE UPPER TROUGH SWINGS
THROUGH THE GREAT LAKES...BUT THESE WILL LIKELY REMAIN JUST TO OUR
NORTH.
TEMPERATURES TODAY WILL BE TRICKY...WITH THE RAIN AND CLOUD COVER.
AREAS SOUTHEAST OF I-70 WILL BE MOST LIKELY TO SEE HEAT INDEX
VALUES NEAR ADVISORY CRITERIA NEAR 105. WILL GO AHEAD AND ISSUE
AN ADVISORY IN THAT AREA FOR THIS AFTERNOON AND EARLY EVENING.
FOR FRIDAY...STILL AM EXPECTING TEMPERATURES INTO THE MID TO UPPER
90S IN THE SOUTHEAST CWA...BUT DRIER AIR IN THE NORTHWEST FLOW
SHOULD KEEP HEAT INDEX VALUES IN CHECK. HIGHS BY SATURDAY SHOULD
MAINLY BE IN THE 80S OVER THE ENTIRE FORECAST AREA.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
UPPER RIDGING WILL PLACE ILLINOIS IN THE NORTHWEST FLOW COMING
DOWN THE TOP OF THE RIDGE THROUGH THE PERIOD. PERIODIC SHORTWAVES
IN THE FLOW WILL LEAD TO RAIN CHANCES AT TIMES...WITH SUNDAY NIGHT
THROUGH MONDAY THE BEST BET AT THE MOMENT. TEMPERATURES WILL BEGIN
TO CREEP BACK UPWARD EARLY NEXT WEEK...WITH HIGHS MAINLY IN THE
LOWER 90S.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ062-063-066>068-
071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
700 AM CDT THU JUL 26 2012
.DISCUSSION...
ISSUED 315 AM CDT THU JUL 26 2012
SERIES OF MCS SYSTEMS LINED UP FROM KANSAS TO LOWER MICHIGAN HAS
BEEN WEAKENING THE LAST COUPLE HOURS. HAVE MANAGED TO GET A FEW
STORMS FIRING IN THE ILLINOIS DESERT ALONG AN OUTFLOW BOUNDARY...
WHICH STRETCHED FROM PITTSFIELD TO PONTIAC AT 2 AM. SOME GUSTS TO
35-40 MPH OCCURRED ALONG THIS BOUNDARY...WITH HIGHER SPEEDS IN
NORTHERN ILLINOIS. HOWEVER...MUCH OF THE LARGER RAIN SHIELD HAS
BEEN DIMINISHING AS IT APPROACHES WEST CENTRAL ILLINOIS. THE
PRIMARY COLD FRONT EXTENDED FROM THE TEXAS PANHANDLE TO LOWER
MICHIGAN...WITH A SECONDARY BOUNDARY FROM NORTHWEST KANSAS TO THE
MINNESOTA ARROWHEAD.
SHORT TERM...TODAY THROUGH SATURDAY...
PRIMARY FORECAST CONCERN DURING THIS PERIOD INVOLVES CONVECTIVE
REDEVELOPMENT TODAY. LATEST HRRR MODEL SHOWS A WEAKENING TREND
CONTINUING WITH THE EXISTING CONVECTION AS IT MOVES THROUGH
ILLINOIS. ADDITIONAL DEVELOPMENT SHOULD START FIRING TOWARD MIDDAY
AS THE MAIN COLD FRONT APPROACHES SOUTHEAST ILLINOIS TOWARD EARLY
AFTERNOON. ENTIRE CWA IS UNDER A SLIGHT RISK OF SEVERE WEATHER FOR
TODAY...HOWEVER THE BETTER CHANCES WILL BE CLOSER TO THE I-70
CORRIDOR AHEAD OF THE FRONT...WHERE THE ATMOSPHERE WILL BE LESS
OVERTURNED BY THE EARLY MORNING CONVECTION. LATEST NAM MODEL
PROJECTS 3000 J/KG OF CAPE IN THIS AREA BY THE TIME THE FRONT
ARRIVES. MOST OF THE RAIN SHOULD BE OUT OF THE AREA BY EARLY
EVENING...BUT WILL LINGER SOME SMALL POPS EAST OF I-57 INTO
EVENING. SOME ADDITIONAL SHOWERS AND STORMS WILL OCCUR OVER
PORTIONS OF THE MIDWEST FRIDAY...AS THE UPPER TROUGH SWINGS
THROUGH THE GREAT LAKES...BUT THESE WILL LIKELY REMAIN JUST TO OUR
NORTH.
TEMPERATURES TODAY WILL BE TRICKY...WITH THE RAIN AND CLOUD COVER.
AREAS SOUTHEAST OF I-70 WILL BE MOST LIKELY TO SEE HEAT INDEX
VALUES NEAR ADVISORY CRITERIA NEAR 105. WILL GO AHEAD AND ISSUE
AN ADVISORY IN THAT AREA FOR THIS AFTERNOON AND EARLY EVENING.
FOR FRIDAY...STILL AM EXPECTING TEMPERATURES INTO THE MID TO UPPER
90S IN THE SOUTHEAST CWA...BUT DRIER AIR IN THE NORTHWEST FLOW
SHOULD KEEP HEAT INDEX VALUES IN CHECK. HIGHS BY SATURDAY SHOULD
MAINLY BE IN THE 80S OVER THE ENTIRE FORECAST AREA.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
UPPER RIDGING WILL PLACE ILLINOIS IN THE NORTHWEST FLOW COMING
DOWN THE TOP OF THE RIDGE THROUGH THE PERIOD. PERIODIC SHORTWAVES
IN THE FLOW WILL LEAD TO RAIN CHANCES AT TIMES...WITH SUNDAY NIGHT
THROUGH MONDAY THE BEST BET AT THE MOMENT. TEMPERATURES WILL BEGIN
TO CREEP BACK UPWARD EARLY NEXT WEEK...WITH HIGHS MAINLY IN THE
LOWER 90S.
GEELHART
&&
.AVIATION...
ISSUED 655 AM CDT THU JUL 26 2012
FORECAST COMPLICATIONS ARE MULTIPLE BOUNDARIES...OUTFLOWS...AND
SCT PRECIP ON SAT IMAGERY FALLING APART AS IT RUNS INTO DRY AIR
OVER CENTRAL ILLINOIS. CONFIDENCE IN ANY MODEL SOLUTION FOR PRECIP
IS MINIMAL AS MOST OF THEM ARE COMING IN TOO WET. REFIRE OF ANY
MESO OR SYNOPTIC SCALE BOUNDARIES THROUGH THE AFTERNOON IS ALLUDED
TO...BUT NOTHING HAS HIGH ENOUGH CONFIDENCE TO GO WITH IT JUST
YET. SO FORECAST REMAINS AN ISSUE OF WINDS FROM SW TO NW...AND MID
LEVEL CLOUDS. SOME CU DEVELOPMENT EXPECTED UNDER THE AC AS WELL.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
ILZ062-063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
315 AM CDT THU JUL 26 2012
.DISCUSSION...
ISSUED 315 AM CDT THU JUL 26 2012
SERIES OF MCS SYSTEMS LINED UP FROM KANSAS TO LOWER MICHIGAN HAS
BEEN WEAKENING THE LAST COUPLE HOURS. HAVE MANAGED TO GET A FEW
STORMS FIRING IN THE ILLINOIS DESERT ALONG AN OUTFLOW BOUNDARY...
WHICH STRETCHED FROM PITTSFIELD TO PONTIAC AT 2 AM. SOME GUSTS TO
35-40 MPH OCCURRED ALONG THIS BOUNDARY...WITH HIGHER SPEEDS IN
NORTHERN ILLINOIS. HOWEVER...MUCH OF THE LARGER RAIN SHIELD HAS
BEEN DIMINISHING AS IT APPROACHES WEST CENTRAL ILLINOIS. THE
PRIMARY COLD FRONT EXTENDED FROM THE TEXAS PANHANDLE TO LOWER
MICHIGAN...WITH A SECONDARY BOUNDARY FROM NORTHWEST KANSAS TO THE
MINNESOTA ARROWHEAD.
SHORT TERM...TODAY THROUGH SATURDAY...
PRIMARY FORECAST CONCERN DURING THIS PERIOD INVOLVES CONVECTIVE
REDEVELOPMENT TODAY. LATEST HRRR MODEL SHOWS A WEAKENING TREND
CONTINUING WITH THE EXISTING CONVECTION AS IT MOVES THROUGH
ILLINOIS. ADDITIONAL DEVELOPMENT SHOULD START FIRING TOWARD MIDDAY
AS THE MAIN COLD FRONT APPROACHES SOUTHEAST ILLINOIS TOWARD EARLY
AFTERNOON. ENTIRE CWA IS UNDER A SLIGHT RISK OF SEVERE WEATHER FOR
TODAY...HOWEVER THE BETTER CHANCES WILL BE CLOSER TO THE I-70
CORRIDOR AHEAD OF THE FRONT...WHERE THE ATMOSPHERE WILL BE LESS
OVERTURNED BY THE EARLY MORNING CONVECTION. LATEST NAM MODEL
PROJECTS 3000 J/KG OF CAPE IN THIS AREA BY THE TIME THE FRONT
ARRIVES. MOST OF THE RAIN SHOULD BE OUT OF THE AREA BY EARLY
EVENING...BUT WILL LINGER SOME SMALL POPS EAST OF I-57 INTO
EVENING. SOME ADDITIONAL SHOWERS AND STORMS WILL OCCUR OVER
PORTIONS OF THE MIDWEST FRIDAY...AS THE UPPER TROUGH SWINGS
THROUGH THE GREAT LAKES...BUT THESE WILL LIKELY REMAIN JUST TO OUR
NORTH.
TEMPERATURES TODAY WILL BE TRICKY...WITH THE RAIN AND CLOUD COVER.
AREAS SOUTHEAST OF I-70 WILL BE MOST LIKELY TO SEE HEAT INDEX
VALUES NEAR ADVISORY CRITERIA NEAR 105. WILL GO AHEAD AND ISSUE
AN ADVISORY IN THAT AREA FOR THIS AFTERNOON AND EARLY EVENING.
FOR FRIDAY...STILL AM EXPECTING TEMPERATURES INTO THE MID TO UPPER
90S IN THE SOUTHEAST CWA...BUT DRIER AIR IN THE NORTHWEST FLOW
SHOULD KEEP HEAT INDEX VALUES IN CHECK. HIGHS BY SATURDAY SHOULD
MAINLY BE IN THE 80S OVER THE ENTIRE FORECAST AREA.
LONG TERM...SUNDAY THROUGH WEDNESDAY...
UPPER RIDGING WILL PLACE ILLINOIS IN THE NORTHWEST FLOW COMING
DOWN THE TOP OF THE RIDGE THROUGH THE PERIOD. PERIODIC SHORTWAVES
IN THE FLOW WILL LEAD TO RAIN CHANCES AT TIMES...WITH SUNDAY NIGHT
THROUGH MONDAY THE BEST BET AT THE MOMENT. TEMPERATURES WILL BEGIN
TO CREEP BACK UPWARD EARLY NEXT WEEK...WITH HIGHS MAINLY IN THE
LOWER 90S.
GEELHART
&&
.AVIATION...
ISSUED 1157 PM CDT WED JUL 25 2012
BELIEVE VFR CONDITIONS WILL CONTINUE AT ALL TAF SITES NEXT 24HRS.
AREA OF SHOWERS AND THUNDERSTORMS IS MOVING INTO THE STATE FROM
THE WEST BUT CLOUD LEVELS ARE QUITE HIGH SO WILL HAVE SCT SC WITH
BKN AC ONCE PCPN ARRIVES. QUESTION IS...WILL PCPN GET HERE. NOT
VERY CONFIDENT THAT PCPN WILL REACH ALL SITES GIVEN THE OUTFLOW
BOUNDARIES THAT HAVE ALREADY GUSTED OUT AHEAD OF THE STORMS IN
EASTERN IOWA AND WEST CENTRAL MO. ONLY PLACE WHERE OUTFLOW
BOUNDARY IS WITH STORM IS NERN MO. BELIEVE THIS AREA OF STORMS
WILL BE MOVING ENE TOWARD PIA SO WILL HAVE VCTS AT PIA AT 09Z ONLY
AND VCSH AT ALL OTHER SITES DURING THE MORNING HOURS...10Z-12Z.
LOOKS LIKE PCPN WILL LAST ABOUT 3HRS AT EACH SITE WITH AC BEHIND
THE PCPN. FRONT SHOULD ALSO MOVE THROUGH AROUND SAME TIME. BELIEVE
FRONT WILL BE SOUTH OF SPI/DEC/CMI BY MAX HEATING TIME SO VERY
UNCERTAIN IF THEY WILL SEE ANY PCPN DURING THE AFTERNOON HOURS SO
AM LEAVING IT OUT FOR NOW. OVERNIGHT SHIFT CAN TAKE ANOTHER LOOK
OVERNIGHT ONCE MESOSCALE FEATURES ARE BETTER KNOWN. BKN AC WILL
CONTINUE INTO THE AFTERNOON BUT APPEARS AS THIS IS MOVING OUT AREA
OF CLOUDS AROUND 6KFT WILL MOVE IN BEHIND THE FRONT FOR THE LATE
AFTERNOON AND EVENING HOURS. WINDS WILL BE SOUTHWEST AHEAD OF THE
FRONT THEN BECOME NORTHWEST BEHIND THE PCPN/FRONT...THEN WESTERLY
DURING THE LATE MORNING TO EVENING HOURS.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
ILZ062-063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
614 PM CDT FRI JUL 27 2012
.AVIATION...
A BROAD AREA OF HIGH PRESSURE OVER THE REGION WILL BRING MOSTLY
CLEAR SKIES AND LIGHT WINDS TO THE REGION TONIGHT. THESE
CONDITIONS WILL BE FAVORABLE FOR SOME LIGHT FOG DEVELOPMENT LATE
TONIGHT. KDBQ IS AT THE GREATEST RISK FOR SEEING VSBYS DROP TO 5SM
OR LESS. SATURDAY WITH HIGH PRESSURE OVER THE AREA WINDS WILL BE
LIGHT AND MAINLY FROM THE NORTHEAST. CLOUDS WILL BE LIMITED TO
SOME LATE MORNING AND AFTERNOON SCATTERED FAIR WEATHER CU BASED
AROUND 4KFT.
DLF
&&
.PREV DISCUSSION... /ISSUED 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
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
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
&&
.AVIATION...
CONVECTION HAS INITIATED ON A FRONT/BOUNDARY FROM NORTHWEST
ILLINOIS INTO SOUTHEAST IOWA. RAP MODEL TRENDS SUGGEST TRSA MAY
AFFECT KMLI/KBRL THROUGH 00Z/27. POST FRONTAL CONVECTION WILL BE
POSSIBLE THROUGH 03Z/27 THAT MIGHT AFFECT KCID/KDBQ. AFT 03Z/27
GENERALLY VFR WX IS EXPECTED. THERE IS THE POSSIBILITY OF SOME
MVFR VSBYS DVLPG ARND SUNRISE FRIDAY BUT WAS NOT INCLUDED IN THE
18Z TAFS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
213 PM CDT THU JUL 26 2012
.MESOSCALE UPDATE...
DIFFERENTIAL HEATING ALONG A BOUNDARY RUNNING FROM KVOK TO NEAR
KLWD AT 18Z COMBINED WITH DIFFERENTIAL HEATING IS ALLOWING
CONVECTION TO DEVELOP. THE BOUNDARY MAY BE A VERY DIFFUSE COLD
FRONT AS DEW POINTS DROP RATHER QUICKLY BEHIND IT. RAP TRENDS FROM
THE LIFT TOOL INDICATE A SMALL THETA E GRADIENT ALONG THE FRONT.
THE STRONGEST CONVERGENCE IS PROGGED TO BE OVER NORTHWEST ILLINOIS
THAT MOVES INTO NORTHEAST ILLINOIS OVER THE NEXT FEW HOURS.
THE MORE NUMEROUS CONVECTION SHOULD BE OVER JO
DAVIESS...STEPHENSON...AND CARROLL COUNTIES IN ILLINOIS WITH MORE
ISOLATED CONVECTION FROM JACKSON...CLINTON...AND CEDAR COUNTIES IN
ILLINOIS. ..08..
&&
.AVIATION... /ISSUED 1233 PM CDT THU JUL 26 2012/
LINGERING MVFR CONDITIONS WILL GIVE WAY TO VFR CONDITIONS BY
21Z/26. DENSITY ALTITUDES MAY APPROACH OR EXCEED 3 KFT THROUGH
01Z/27. VCTS WAS INCLUDED IN ALL 18Z TAFS FOR POSSIBLE DIURNAL
CONVECTION DVLPG AFT 21Z/26. HOWEVER...AREAL COVERAGE MAY BE 10
PERCENT OR LESS. IF A TSRA WOULD IMPACT A TAF SITE...BRIEF MVFR
CONDITIONS ARE EXPECTED. AFT 03Z/27 VFR CONDITIONS ARE EXPECTED.
THERE MAY OR MAY NOT BE MVFR VSBYS AROUND SUNRISE FROM FG. IF FG
WOULD DVLP...KCID/KDBQ MAY HAVE A BETTER CHANCE DUE TO WET GROUND
FROM RECENT RAINFALL. ..08..
&&
.PREV DISCUSSION... /ISSUED 1024 AM CDT THU JUL 26 2012/
UPDATE...
RADAR AND RAP TRENDS INDICATE THE LINGERING SHRA/SPRINKLES SHOULD
DISSIPATE BY MID DAY. POST FRONTAL CLOUDS HAVE DEVELOPED ACROSS
PART OF THE AREA WHICH MAY LIMIT THE AMOUNT OF WARMING THIS
AFTERNOON. HOWEVER...THE SUBSIDENCE DEVELOPING BEHIND THE
DEPARTING VORT MAX SHOULD ALLOW CLOUDS TO CLEAR OUT AND ALLOW
TEMPERATURES TO WARM.
ATTENTION THEN TURNS TO THE POTENTIAL FOR DIURNAL CONVECTION THIS
AFTERNOON. IF THE RAP MODEL IS CORRECT THERE WILL BE A LULL IN ANY
PRECIPITATION UNTIL CONVECTIVE TEMPERATURE IS ACHIEVED THIS
AFTERNOON. RAP TRENDS SUGGEST CONVECTIVE TEMPERATURES IN THE UPPER
80S TO LOWER 90S WHICH IS AROUND THE MAX TEMPERATURES.
RIGHT NOW THE SITUATION IS NOT CLEAR. IF DIURNAL CONVECTION DOES
DEVELOP IT MAY BE ISOLATED IN NATURE AND MAY HOLD OFF UNTIL VERY
LATE IN THE AFTERNOON WITH THE APPROACH OF THE NEXT SHORTWAVE.
FOR NOW WILL CONTINUE WITH THE IDEA OF DIURNAL CONVECTION
DEVELOPING BUT LIMIT IT TO THE LATE AFTERNOON HOURS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED AVIATION...
NWS QUAD CITIES IA IL
1233 PM CDT THU JUL 26 2012
.AVIATION UPDATE...
LINGERING MVFR CONDITIONS WILL GIVE WAY TO VFR CONDITIONS BY 21Z/26.
DENSITY ALTITUDES MAY APPROACH OR EXCEED 3 KFT THROUGH 01Z/27. VCTS
WAS INCLUDED IN ALL 18Z TAFS FOR POSSIBLE DIURNAL CONVECTION DVLPG
AFT 21Z/26. HOWEVER...AREAL COVERAGE MAY BE 10 PERCENT OR LESS. IF A
TSRA WOULD IMPACT A TAF SITE...BRIEF MVFR CONDITIONS ARE EXPECTED.
AFT 03Z/27 VFR CONDITIONS ARE EXPECTED. THERE MAY OR MAY NOT BE MVFR
VSBYS AROUND SUNRISE FROM FG. IF FG WOULD DVLP...KCID/KDBQ MAY HAVE
A BETTER CHANCE DUE TO WET GROUND FROM RECENT RAINFALL. ..08..
&&
.PREV DISCUSSION... /ISSUED 1024 AM CDT THU JUL 26 2012/
UPDATE...
RADAR AND RAP TRENDS INDICATE THE LINGERING SHRA/SPRINKLES SHOULD
DISSIPATE BY MID DAY. POST FRONTAL CLOUDS HAVE DEVELOPED ACROSS
PART OF THE AREA WHICH MAY LIMIT THE AMOUNT OF WARMING THIS
AFTERNOON. HOWEVER...THE SUBSIDENCE DEVELOPING BEHIND THE
DEPARTING VORT MAX SHOULD ALLOW CLOUDS TO CLEAR OUT AND ALLOW
TEMPERATURES TO WARM.
ATTENTION THEN TURNS TO THE POTENTIAL FOR DIURNAL CONVECTION THIS
AFTERNOON. IF THE RAP MODEL IS CORRECT THERE WILL BE A LULL IN ANY
PRECIPITATION UNTIL CONVECTIVE TEMPERATURE IS ACHIEVED THIS
AFTERNOON. RAP TRENDS SUGGEST CONVECTIVE TEMPERATURES IN THE UPPER
80S TO LOWER 90S WHICH IS AROUND THE MAX TEMPERATURES.
RIGHT NOW THE SITUATION IS NOT CLEAR. IF DIURNAL CONVECTION DOES
DEVELOP IT MAY BE ISOLATED IN NATURE AND MAY HOLD OFF UNTIL VERY
LATE IN THE AFTERNOON WITH THE APPROACH OF THE NEXT SHORTWAVE.
FOR NOW WILL CONTINUE WITH THE IDEA OF DIURNAL CONVECTION
DEVELOPING BUT LIMIT IT TO THE LATE AFTERNOON HOURS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1224 PM CDT THU JUL 26 2012
.AVIATION...
LINGERING MVFR CONDITIONS WILL GIVE WAY TO VFR CONDITIONS BY
21Z/26. VCTS WAS INCLUDED IN ALL 18Z TAFS FOR POSSIBLE DIURNAL
CONVECTION DVLPG AFT 21Z/26. HOWEVER...AREAL COVERAGE MAY BE 10
PERCENT OR LESS. IF A TSRA WOULD IMPACT A TAF SITE...BRIEF MVFR
CONDITIONS ARE EXPECTED. AFT 03Z/27 VFR CONDITIONS ARE EXPECTED.
THERE MAY OR MAY NOT BE MVFR VSBYS AROUND SUNRISE FROM FG. IF FG
WOULD DVLP...KCID/KDBQ MAY HAVE A BETTER CHANCE DUE TO WET GROUND
FROM RECENT RAINFALL. ..08..
&&
.PREV DISCUSSION... /ISSUED 1024 AM CDT THU JUL 26 2012/
UPDATE...
RADAR AND RAP TRENDS INDICATE THE LINGERING SHRA/SPRINKLES SHOULD
DISSIPATE BY MID DAY. POST FRONTAL CLOUDS HAVE DEVELOPED ACROSS
PART OF THE AREA WHICH MAY LIMIT THE AMOUNT OF WARMING THIS
AFTERNOON. HOWEVER...THE SUBSIDENCE DEVELOPING BEHIND THE
DEPARTING VORT MAX SHOULD ALLOW CLOUDS TO CLEAR OUT AND ALLOW
TEMPERATURES TO WARM.
ATTENTION THEN TURNS TO THE POTENTIAL FOR DIURNAL CONVECTION THIS
AFTERNOON. IF THE RAP MODEL IS CORRECT THERE WILL BE A LULL IN ANY
PRECIPITATION UNTIL CONVECTIVE TEMPERATURE IS ACHIEVED THIS
AFTERNOON. RAP TRENDS SUGGEST CONVECTIVE TEMPERATURES IN THE UPPER
80S TO LOWER 90S WHICH IS AROUND THE MAX TEMPERATURES.
RIGHT NOW THE SITUATION IS NOT CLEAR. IF DIURNAL CONVECTION DOES
DEVELOP IT MAY BE ISOLATED IN NATURE AND MAY HOLD OFF UNTIL VERY
LATE IN THE AFTERNOON WITH THE APPROACH OF THE NEXT SHORTWAVE.
FOR NOW WILL CONTINUE WITH THE IDEA OF DIURNAL CONVECTION
DEVELOPING BUT LIMIT IT TO THE LATE AFTERNOON HOURS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1024 AM CDT THU JUL 26 2012
.UPDATE...
RADAR AND RAP TRENDS INDICATE THE LINGERING SHRA/SPRINKLES SHOULD
DISSIPATE BY MID DAY. POST FRONTAL CLOUDS HAVE DEVELOPED ACROSS
PART OF THE AREA WHICH MAY LIMIT THE AMOUNT OF WARMING THIS
AFTERNOON. HOWEVER...THE SUBSIDENCE DEVELOPING BEHIND THE
DEPARTING VORT MAX SHOULD ALLOW CLOUDS TO CLEAR OUT AND ALLOW
TEMPERATURES TO WARM.
ATTENTION THEN TURNS TO THE POTENTIAL FOR DIURNAL CONVECTION THIS
AFTERNOON. IF THE RAP MODEL IS CORRECT THERE WILL BE A LULL IN ANY
PRECIPITATION UNTIL CONVECTIVE TEMPERATURE IS ACHIEVED THIS
AFTERNOON. RAP TRENDS SUGGEST CONVECTIVE TEMPERATURES IN THE UPPER
80S TO LOWER 90S WHICH IS AROUND THE MAX TEMPERATURES.
RIGHT NOW THE SITUATION IS NOT CLEAR. IF DIURNAL CONVECTION DOES
DEVELOP IT MAY BE ISOLATED IN NATURE AND MAY HOLD OFF UNTIL VERY
LATE IN THE AFTERNOON WITH THE APPROACH OF THE NEXT SHORTWAVE.
FOR NOW WILL CONTINUE WITH THE IDEA OF DIURNAL CONVECTION
DEVELOPING BUT LIMIT IT TO THE LATE AFTERNOON HOURS. ..08..
&&
.AVIATION...
CONSIDERABLE POST FRONTAL MVFR CIGS HAVE DVLPD ACRS IOWA AND THESE
ARE EXPECTED TO CONTINUE THROUGH 18Z/26. AFT 18Z/26 MVFR CIGS
SHOULD BREAK UP ALLOWING VFR CONDITIONS THROUGH 00Z/27. THERE IS A
POSSIBILITY OF DIURNAL CONVECTION DVLPG AFT 20Z/26. THE POTENTIAL
WILL BE THERE BUT COVERAGE MAY ONLY WARRANT VCSH OR VCTS IN THE
18Z TAFS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS DES MOINES IA
1155 PM CDT WED JUL 25 2012
.UPDATED FOR 26/06Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
MAIN FORECAST CONCERN IS WITH TIMING OF COLD FRONT AND CONVECTION
POTENTIAL THIS EVENING INTO THE OVERNIGHT HOURS. NAM/RAP SEEM TO
HAVE A DECENT HANDLE ON INITIATION OF CONVECTION AND LEANED TOWARD
TIMING OF FRONT/POPS. THE 16Z HRRR HAS SOME ISOLATED CONVECTION
DEVELOPING B/T 22-00Z BUT THINKING CAP IS STILL TOO STRONG FOR MUCH
CONVECTION TO GET GOING UNTIL AFTER 00Z. REALLY CUT BACK ON POPS
UNTIL AFTER 00Z OVER THE CENTRAL AND SOUTHEAST CWA. THE 12Z 4.0KM
WRF MODEL RUNS FROM NSSL AND NCEP BOTH HAVE VERY SPOTTY PRECIP
THROUGH TONIGHT...AND SORT OF LIGHTS UP THE FRONT SOUTH OF
INTERSTATE 80 AFTER 02Z THURSDAY. HAVE LOW CONFIDENCE WITH ANY
WIDESPREAD SIGNIFICANT CONVECTION TONIGHT. MODELS FORECASTING PW
VALUES NEAR 2 INCHES GENERALLY ALONG THE FRONT...AND 1-1.5 INCHES
BEHIND IT. HOWEVER...WITH SUCH SPOTTY CONVECTION AND LOWERED QPF
AMOUNTS TO LESS THAN A HALF INCH THROUGHOUT THE FORECAST
AREA...ESPECIALLY WITH SUCH HIGH BASED CONVECTION. PLENTY OF SURFACE
BASED INSTABILITY...BUT LITTLE IF ANY EFFECTIVE SHEAR AVAILABLE...AS
WELL AS FORCING OTHER THAN THE FRONTAL BOUNDARY TONIGHT. THINKING
MAIN SEVERE THREAT WILL BE WINDS WITH THE DRY AIRMASS PRESENT.
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
LARGE SCALE MAINLY POST FRONTAL FORCING SHOULD BE JUST EXITING
FORECAST AREA BY THE START OF THE PERIOD SO ANY LINGERING
PRECIP...IF ANY...SHOULD BE MOVING INTO MO AND IL. FORECAST DRY
AFTER 15Z. PREVIOUS FORECAST HAD LOW POPS BRUSHING NERN IA BY LATE
AFTERNOON BUT CANNOT REALLY FIND ANY SUPPORT FOR THIS WITH LIMITED
FORCING AND INSUFFICIENT MOISTURE...AND EVEN THAT LOOKS TO BE POST
00Z. UPSTREAM NRN PLAINS AIRMASS WILL GRADUALLY PASS THROUGH IA
DURING THE DAY BUT DEEP NW FLOW AND MIXING WILL STILL ALLOW
CENTRAL/SRN HIGHS TO REACH LOW/MID 90S BY AFTERNOON. DO NOT
ANTICIPATED ENOUGH PRECIP TONIGHT TO AFFECT THAT. BLEND OF SREF/NAM
SOUNDINGS SEEMS REASONABLE.
NRN PLAINS SURFACE RIDGE WILL RETURN IA TEMPS TO NORMAL FOR FRI WITH
CONTINUED DRY WEATHER AS GREAT LAKES SHORT WAVE DEPARTS. THIS WILL
BE FOLLOWED BY AN EXTENDED PERIOD OF ROCKIES AND HIGH PLAINS
RIDGING...RIGHT INTO WED AND BEYOND...LEAVING IA WITH WARM BUT NOT
EXTREME TEMPS AND LOW END PRECIP POTENTIAL. CHANCES INCREASE
SOMEWHAT THIS WEEKEND AS SHORT WAVE TOPS THE RIDGE INCREASING
FORCING...ESPECIALLY THERMODYNAMIC...BY SAT. THIS WEAK FORCING
LINGERS INTO SUN...AND POSSIBLY EARLY MON LEADING TO SEVERAL DAYS
WORTH OF CHANCE POPS. MODELS CONTINUE TO DABBLE IN WEAK QPF EVENTS
AFTER THIS TIME...BUT THERE IS REALLY NO CONSISTENT FORCING FEATURE
TO LATCH ONTO SO HAVE LEFT MON NIGHT-WED DRY AT THIS POINT.
REGARDING TEMPS..ONLY REAL CONCERN IS LOW CONFIDENCE FORECAST
SATURDAY. QUESTIONS ON HOW MUCH WE WILL MIX IN NEW REGIME WITH
LIGHT WINDS. HAVE PRETTY MUCH MIXED THINGS OUT TO 900-850MB OR
MORE...MIXING SEASONALLY...BUT FEEL NAM IS UNDERDONE WHICH SEEMS TO
BE THE CASE AT TIMES IN WEAK FLOW.
&&
.AVIATION...26/00Z
MAIN FRONT HAS PUSHED THROUGH CENTRAL IOWA BUT INSTABILITY AND WEAK
SHEAR BEHIND THE BOUNDARY HAVE BEEN KEEPING THE STORMS GOING.
STORMS WILL BE IN THE KALO/KDSM AND KOTM TAFS THROUGH 09Z. A
SECONDARY BOUNDARY SHIFTS ACROSS THE FORECAST AREA DURING THE DAY
BUT THERE IS NO UPPER LEVEL SUPPORT WITH THIS SO EXCEPT FOR SOME
CLOUDS AND A SECOND SHOT OF NW WINDS AT 10-20KTS THAT SHOULD BE THE
ONLY SENSIBLE WEATHER. VFR CONDITIONS EXPECTED.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...SMALL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
652 AM CDT THU JUL 26 2012
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 1208 AM CDT THU JUL 26 2012
AT 00Z THURSDAY A -14C 500MB UPPER LOW WAS LOCATED NEAR SOUTHERN
MANITOBA AND A 500MB UPPER RIDGE WAS PLACED ACROSS THE SOUTHWEST
UNITED STATES. AT THE 250MB LEVEL A 75KT JET WAS MOVING OVER THE
UPPER RIDGE AXIS WITH THE NOSE OF THIS UPPER JET LOCATED NEAR
EASTERN WYOMING. ALSO ACROSS EASTERN WYOMING AND WESTERN NEBRASKA
AT 00Z THURSDAY WAS A 500MB THERMAL TROUGH. A 700MB BAROCLINIC
ZONE STRETCHED FROM EASTERN NEBRASKA IN TO NORTHEAST COLORADO. A
850MB COLD FRONT EXTENDED FROM SOUTHEAST NEBRASKA INTO NORTHWEST
KANSAS/EASTERN COLORADO. AT THE SURFACE A COLD FRONT APPEARS TO BE
LOCATED ACROSS NORTH CENTRAL AND SOUTHWEST KANSAS WITH MULTIPLE
OUTFLOW BOUNDARIES ALSO PRESENT FROM THE ONGOING CONVECTION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 133 AM CDT THU JUL 26 2012
CONVECTION EARLIER THIS MORNING APPEARS TO HAVE RELATED WELL WITH AN
AREA OF 850-700MB FRONTOGENESIS OCCURRING AHEAD OF A 500MB TROUGH.
LATEST RAP AND NAM WERE IN DECENT AGREEMENT AND PLACES THIS ARE OF
BETTER FORCING EAST/SOUTHEAST OF DODGE CITY BETWEEN 09Z AND 12Z
THURSDAY. WILL CONTINUE TO MONITOR RADAR TREND BUT AT THIS TIME
THIS AREA OF CONVECTION SHOULD BE EXITING SOUTH CENTRAL KANSAS
AROUND 12Z.
MORNING CLOUD COVER WILL GIVE WAY TO CLEARING SKIES AS THE UPPER
TROUGH MOVES INTO CENTRAL KANSAS. 850MB TEMPERATURES DO INDICATED
A COOLING TREND TODAY AND BY 00Z FRIDAY THE 850MB TEMPERATURES ARE
FORECAST TO RANGE FROM 23-25C IN CENTRAL KANSAS TO THE UPPER 20S TO
NEAR 30C NEAR THE COLORADO BORDER. GIVEN THESE TEMPERATURES ALONG
WITH THE OVERNIGHT RAINFALL AND A EAST/NORTHEASTERLY FLOW IN THE
LOWER LEVELS WILL TREND TOWARDS KEEPING TEMPERATURES CLOSER TO THE
PREVIOUS FORECAST WHICH WERE COOLER THAN THE NAM 2M TEMPERATURES
BUT NOT AS COOL AS THE GFS.
TONIGHT AN UPPER LEVEL RIDGE AXIS WILL BUILD EAST INTO THE
ROCKIES AS SUBTLE UPPER LEVEL DISTURBANCE ROTATES OUT INTO THE
PLAINS. BASED ON MODEL SOUNDINGS MOISTURE AND INSTABILITY WILL
CONTINUE WITH A DRY FORECAST. LOWS BOTTOMING OUT IN THE MID 60S TO
AROUND 70S STILL APPEARS TO BE ON TRACK.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 236 AM CDT THU JUL 26 2012
UPPER LEVEL RIDGING WILL BE THE DOMINANT FEATURE ON FRIDAY. A
NORTHWESTERLY JET STREAK WILL BE OVER THE NORTHERN PLAINS, WITH WEAK
SURFACE HIGH PRESSURE ACROSS THE UPPER MIDWEST. RELATIVE HUMIDITY
FIELDS FROM THE GFS AND ECMWF INDICATE THE PRESENCE OF MID LEVEL
MOISTURE. HOWEVER THE LOW LEVELS ARE LIKELY TO BE MUCH DRIER, AND
TEMPERATURES WILL QUICKLY RISE INTO THE UPPER 90S BY EARLY
AFTERNOON. THE WEAK SURFACE PRESSURE PATTERN FEATURING A NORTHERN
HIGH PLAINS TROUGH WILL CONTRIBUTE TO DEVELOPMENT OF LIGHT SOUTHEAST
SURFACE WINDS FRIDAY.
MOVING FARTHER INTO THE WEEKEND, THE UPPER RIDGE BEGINS TO DRIFT
SLIGHTLY FARTHER SOUTHEAST, AND THE UPPER JET SEGMENTS THAT WERE
PREVIOUSLY STREAKING THROUGH THE NORTHERN PLAINS BECOME SHIFTED
CLOSER TO THE CENTRAL PLAINS. DURING THE LATE WEEKEND INTO EARLY
NEXT WEEK, A CONDITIONALLY UNSTABLE AIRMASS WILL BE IN PLACE, WITH
THE POTENTIAL FOR LATE DAY SURFACE BASED CONVECTION ALONG WEAK
SURFACE CONVERGENCE ZONES. SUBTLE SHORTWAVE ENERGY COULD ALSO COME
INTO PLAY AND ENHANCE LIFT FOR ELEVATED CONVECTION INTO THE LATER
HOURS THROUGH ABOUT TUESDAY EVENING.
ASSOCIATED WITH THE PERSISTENT UPPER RIDGING THROUGH THE CENTRAL AND
SOUTHERN PLAINS, TEMPERATURES WILL REMAIN VERY WARM IN THE UPPER 90S
TO AROUND 100 DEGREES FOR DAILY HIGHS. ADDED TO THIS WILL BE SOME
UNCERTAINTY IN VARIABILITY IF ANY PERIODS OF ENHANCED CLOUDINESS OR
EARLY AFTERNOON THUNDERSTORMS DEVELOP, AUGMENTING LOCAL TEMPERATURES.
OVERNIGHT LOWS SHOULD REMAIN MILD AS WELL, GENERALLY IN THE UPPER
60S, THROUGH THE 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 649 AM CDT THU JUL 26 2012
INFRARED SATELLITE IMAGERY AND AND REGIONAL METAR OBSERVATIONS
INDICATES CLEARING BELOW 12KFT ACROSS THE AREA THIS MORNING. THE
CLEARING TREND IS EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE
MORNING, AS RADAR IMAGERY CONTINUES TO INDICATE AS WEAK MCV EXITING
INTO WESTERN OKLAHOMA. NORTHEAST SURFACE WINDS SHOULD INCREASE WITH
MODERATE GUSTS TO AROUND 20 KNOTS BY LATE MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 95 67 101 71 / 10 10 10 10
GCK 95 66 100 70 / 10 10 10 10
EHA 94 67 98 69 / 0 10 10 10
LBL 96 67 100 70 / 0 10 10 10
HYS 97 66 101 71 / 10 10 10 10
P28 97 70 103 73 / 20 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...RUSSELL
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
238 AM CDT THU JUL 26 2012
.SYNOPSIS...
ISSUED AT 1208 AM CDT THU JUL 26 2012
AT 00Z THURSDAY A -14C 500MB UPPER LOW WAS LOCATED NEAR SOUTHERN
MANITOBA AND A 500MB UPPER RIDGE WAS PLACED ACROSS THE SOUTHWEST
UNITED STATES. AT THE 250MB LEVEL A 75KT JET WAS MOVING OVER THE
UPPER RIDGE AXIS WITH THE NOSE OF THIS UPPER JET LOCATED NEAR
EASTERN WYOMING. ALSO ACROSS EASTERN WYOMING AND WESTERN NEBRASKA
AT 00Z THURSDAY WAS A 500MB THERMAL TROUGH. A 700MB BAROCLINIC
ZONE STRETCHED FROM EASTERN NEBRASKA IN TO NORTHEAST COLORADO. A
850MB COLD FRONT EXTENDED FROM SOUTHEAST NEBRASKA INTO NORTHWEST
KANSAS/EASTERN COLORADO. AT THE SURFACE A COLD FRONT APPEARS TO BE
LOCATED ACROSS NORTH CENTRAL AND SOUTHWEST KANSAS WITH MULTIPLE
OUTFLOW BOUNDARIES ALSO PRESENT FROM THE ONGOING CONVECTION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 133 AM CDT THU JUL 26 2012
CONVECTION EARLIER THIS MORNING APPEARS TO HAVE RELATED WELL WITH AN
AREA OF 850-700MB FRONTOGENESIS OCCURRING AHEAD OF A 500MB TROUGH.
LATEST RAP AND NAM WERE IN DECENT AGREEMENT AND PLACES THIS ARE OF
BETTER FORCING EAST/SOUTHEAST OF DODGE CITY BETWEEN 09Z AND 12Z
THURSDAY. WILL CONTINUE TO MONITOR RADAR TREND BUT AT THIS TIME
THIS AREA OF CONVECTION SHOULD BE EXITING SOUTH CENTRAL KANSAS
AROUND 12Z.
MORNING CLOUD COVER WILL GIVE WAY TO CLEARING SKIES AS THE UPPER
TROUGH MOVES INTO CENTRAL KANSAS. 850MB TEMPERATURES DO INDICATED
A COOLING TREND TODAY AND BY 00Z FRIDAY THE 850MB TEMPERATURES ARE
FORECAST TO RANGE FROM 23-25C IN CENTRAL KANSAS TO THE UPPER 20S TO
NEAR 30C NEAR THE COLORADO BORDER. GIVEN THESE TEMPERATURES ALONG
WITH THE OVERNIGHT RAINFALL AND A EAST/NORTHEASTERLY FLOW IN THE
LOWER LEVELS WILL TREND TOWARDS KEEPING TEMPERATURES CLOSER TO THE
PREVIOUS FORECAST WHICH WERE COOLER THAN THE NAM 2M TEMPERATURES
BUT NOT AS COOL AS THE GFS.
TONIGHT AN UPPER LEVEL RIDGE AXIS WILL BUILD EAST INTO THE
ROCKIES AS SUBTLE UPPER LEVEL DISTURBANCE ROTATES OUT INTO THE
PLAINS. BASED ON MODEL SOUNDINGS MOISTURE AND INSTABILITY WILL
CONTINUE WITH A DRY FORECAST. LOWS BOTTOMING OUT IN THE MID 60S TO
AROUND 70S STILL APPEARS TO BE ON TRACK.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 236 AM CDT THU JUL 26 2012
UPPER LEVEL RIDGING WILL BE THE DOMINANT FEATURE ON FRIDAY. A
NORTHWESTERLY JET STREAK WILL BE OVER THE NORTHERN PLAINS, WITH WEAK
SURFACE HIGH PRESSURE ACROSS THE UPPER MIDWEST. RELATIVE HUMIDITY
FIELDS FROM THE GFS AND ECMWF INDICATE THE PRESENCE OF MID LEVEL
MOISTURE. HOWEVER THE LOW LEVELS ARE LIKELY TO BE MUCH DRIER, AND
TEMPERATURES WILL QUICKLY RISE INTO THE UPPER 90S BY EARLY
AFTERNOON. THE WEAK SURFACE PRESSURE PATTERN FEATURING A NORTHERN
HIGH PLAINS TROUGH WILL CONTRIBUTE TO DEVELOPMENT OF LIGHT SOUTHEAST
SURFACE WINDS FRIDAY.
MOVING FARTHER INTO THE WEEKEND, THE UPPER RIDGE BEGINS TO DRIFT
SLIGHTLY FARTHER SOUTHEAST, AND THE UPPER JET SEGMENTS THAT WERE
PREVIOUSLY STREAKING THROUGH THE NORTHERN PLAINS BECOME SHIFTED
CLOSER TO THE CENTRAL PLAINS. DURING THE LATE WEEKEND INTO EARLY
NEXT WEEK, A CONDITIONALLY UNSTABLE AIRMASS WILL BE IN PLACE, WITH
THE POTENTIAL FOR LATE DAY SURFACE BASED CONVECTION ALONG WEAK
SURFACE CONVERGENCE ZONES. SUBTLE SHORTWAVE ENERGY COULD ALSO COME
INTO PLAY AND ENHANCE LIFT FOR ELEVATED CONVECTION INTO THE LATER
HOURS THROUGH ABOUT TUESDAY EVENING.
ASSOCIATED WITH THE PERSISTENT UPPER RIDGING THROUGH THE CENTRAL AND
SOUTHERN PLAINS, TEMPERATURES WILL REMAIN VERY WARM IN THE UPPER 90S
TO AROUND 100 DEGREES FOR DAILY HIGHS. ADDED TO THIS WILL BE SOME
UNCERTAINTY IN VARIABILITY IF ANY PERIODS OF ENHANCED CLOUDINESS OR
EARLY AFTERNOON THUNDERSTORMS DEVELOP, AUGMENTING LOCAL TEMPERATURES.
OVERNIGHT LOWS SHOULD REMAIN MILD AS WELL, GENERALLY IN THE UPPER
60S, THROUGH THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1208 AM CDT THU JUL 26 2012
CONVECTION OCCURRING ACROSS SOUTHWEST AND NORTH CENTRAL KANSAS
WILL MOVE OUT OF THE DDC AND HYS TAF SITES BY 07Z BASED ON LATEST
RADAR TRENDS AND THE MOVEMENT OF AN AREA OF 850-700MB
FRONTOGENESIS AHEAD OF A 500MB TROUGH BASED ON THE LATEST RAPS.
BUFR SOUNDINGS SUGGESTING SKIES WILL CLEAR THROUGH THE EARLY MORNING
HOURS WITH VFR CONDITIONS EXPECTED THOUGH OUT THE PERIOD. VARIABLE
WINDS DUE TO THE SEVERAL OUTFLOW BOUNDARIES LOCATED ACROSS WESTERN
KANSAS WILL BECOME PRIMARILY FROM THE NORTHEAST BY 09Z AS A COLD
FRONT MOVES SOUTHEAST INTO NORTHWEST OKLAHOMA AND SOUTH CENTRAL
KANSAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 95 67 101 71 / 0 10 10 10
GCK 95 66 100 70 / 0 10 10 10
EHA 94 67 98 69 / 0 10 10 10
LBL 96 67 100 70 / 0 10 10 10
HYS 97 66 101 71 / 10 10 10 10
P28 97 70 103 73 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...RUSSELL
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
145 AM CDT THU JUL 26 2012
...UPDATED SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1208 AM CDT THU JUL 26 2012
AT 00Z THURSDAY A -14C 500MB UPPER LOW WAS LOCATED NEAR SOUTHERN
MANITOBA AND A 500MB UPPER RIDGE WAS PLACED ACROSS THE SOUTHWEST
UNITED STATES. AT THE 250MB LEVEL A 75KT JET WAS MOVING OVER THE
UPPER RIDGE AXIS WITH THE NOSE OF THIS UPPER JET LOCATED NEAR
EASTERN WYOMING. ALSO ACROSS EASTERN WYOMING AND WESTERN NEBRASKA
AT 00Z THURSDAY WAS A 500MB THERMAL TROUGH. A 700MB BAROCLINIC
ZONE STRETCHED FROM EASTERN NEBRASKA IN TO NORTHEAST COLORADO. A
850MB COLD FRONT EXTENDED FROM SOUTHEAST NEBRASKA INTO NORTHWEST
KANSAS/EASTERN COLORADO. AT THE SURFACE A COLD FRONT APPEARS TO BE
LOCATED ACROSS NORTH CENTRAL AND SOUTHWEST KANSAS WITH MULTIPLE
OUTFLOW BOUNDARIES ALSO PRESENT FROM THE ONGOING CONVECTION.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 133 AM CDT THU JUL 26 2012
CONVECTION EARLIER THIS MORNING APPEARS TO HAVE RELATED WELL WITH AN
AREA OF 850-700MB FRONTOGENESIS OCCURRING AHEAD OF A 500MB TROUGH.
LATEST RAP AND NAM WERE IN DECENT AGREEMENT AND PLACES THIS ARE OF
BETTER FORCING EAST/SOUTHEAST OF DODGE CITY BETWEEN 09Z AND 12Z
THURSDAY. WILL CONTINUE TO MONITOR RADAR TREND BUT AT THIS TIME
THIS AREA OF CONVECTION SHOULD BE EXITING SOUTH CENTRAL KANSAS
AROUND 12Z.
MORNING CLOUD COVER WILL GIVE WAY TO CLEARING SKIES AS THE UPPER
TROUGH MOVES INTO CENTRAL KANSAS. 850MB TEMPERATURES DO INDICATED
A COOLING TREND TODAY AND BY 00Z FRIDAY THE 850MB TEMPERATURES ARE
FORECAST TO RANGE FROM 23-25C IN CENTRAL KANSAS TO THE UPPER 20S TO
NEAR 30C NEAR THE COLORADO BORDER. GIVEN THESE TEMPERATURES ALONG
WITH THE OVERNIGHT RAINFALL AND A EAST/NORTHEASTERLY FLOW IN THE
LOWER LEVELS WILL TREND TOWARDS KEEPING TEMPERATURES CLOSER TO THE
PREVIOUS FORECAST WHICH WERE COOLER THAN THE NAM 2M TEMPERATURES
BUT NOT AS COOL AS THE GFS.
TONIGHT AN UPPER LEVEL RIDGE AXIS WILL BUILD EAST INTO THE
ROCKIES AS SUBTLE UPPER LEVEL DISTURBANCE ROTATES OUT INTO THE
PLAINS. BASED ON MODEL SOUNDINGS MOISTURE AND INSTABILITY WILL
CONTINUE WITH A DRY FORECAST. LOWS BOTTOMING OUT IN THE MID 60S TO
AROUND 70S STILL APPEARS TO BE ON TRACK.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 344 PM CDT WED JUL 25 2012
THE ECMWF, GFS AND GFS ENSEMBLES ARE IN FAIRLY GOOD AGREEMENT WITH
THE LARGE SCALE UPPER-LEVEL PATTERN OVER THE NEXT WEEK. UPPER LEVEL
RIDGING WILL EDGE EASTWARD ACROSS THE HIGH PLAINS FROM THURSDAY INTO
SATURDAY. LOW LEVEL CONVERGENCE BOUNDARIES WILL BE LACKING SO THAT
PRECIPITATION CHANCES ARE LOW. TEMPERATURES SHOULD REMAIN RATHER
HOT AROUND 100F. UPPER LEVEL RIDGING WILL BUILD ACROSS OKLAHOMA
FROM SUNDAY INTO TUESDAY. VERY HOT AIR WILL BE SITUATED ALONG AND
JUST NORTH OF THE UPPER LEVEL RIDGE AXIS, WITH HIGHS FROM 100 TO
110F. THE ECMWF SHOWS A WEAK FRONTAL BOUNDARY SITUATED ALONG THE
NORTHERN PERIPHERY OF THE UPPER RIDGE, WITH COOLER TEMPERATURES TO
THE NORTH AND BLAZING HOT TEMPERATURES TO THE SOUTH. IT CURRENTLY
APPEARS THAT THE VERY HOT TEMPERATURES MAY BE CONFINED TO SOUTH
CENTRAL AND PARTS OF SOUTHWEST KANSAS, WITH THE COOLER READINGS TO
THE NORTH. ISOLATED THUNDERSTORM CHANCES CANNOT BE RULED OUT ANY
DAY IN THIS PERIOD GIVEN THAT WESTERN KANSAS WILL BE SITUATED
ALONG THE EDGE OF THE WESTERLIES WHERE WEAK SURFACE BOUNDARIES
OFTEN RESIDE IN SUMMER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1208 AM CDT THU JUL 26 2012
CONVECTION OCCURRING ACROSS SOUTHWEST AND NORTH CENTRAL KANSAS
WILL MOVE OUT OF THE DDC AND HYS TAF SITES BY 07Z BASED ON LATEST
RADAR TRENDS AND THE MOVEMENT OF AN AREA OF 850-700MB
FRONTOGENESIS AHEAD OF A 500MB TROUGH BASED ON THE LATEST RAPS.
BUFR SOUNDINGS SUGGESTING SKIES WILL CLEAR THROUGH THE EARLY MORNING
HOURS WITH VFR CONDITIONS EXPECTED THOUGH OUT THE PERIOD. VARIABLE
WINDS DUE TO THE SEVERAL OUTFLOW BOUNDARIES LOCATED ACROSS WESTERN
KANSAS WILL BECOME PRIMARILY FROM THE NORTHEAST BY 09Z AS A COLD
FRONT MOVES SOUTHEAST INTO NORTHWEST OKLAHOMA AND SOUTH CENTRAL
KANSAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 95 67 101 71 / 0 10 10 10
GCK 95 66 100 70 / 0 10 10 10
EHA 94 67 98 69 / 0 10 10 10
LBL 96 67 100 70 / 0 10 10 10
HYS 97 66 101 71 / 10 10 10 10
P28 97 70 103 73 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1109 PM MDT WED JUL 25 2012
.UPDATE...
ISSUED AT 1036 PM MDT WED JUL 25 2012
SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OVER THE NORTON AND
HILL CITY AREA THIS EVENING. AM EXPECTING THE ACTIVITY TO MOVE
EAST IN THE NEXT HOUR OR SO AS THE LIFT BEHIND THE COLD FRONT FROM
AN UPPER LEVEL SHORT WAVE TROUGH MOVES SOUTHEAST.
FOR THURSDAY TEMPERATURES WILL CONTINUE TO BE COOLER THAN WHAT WE
HAVE HAD...WITH HIGHS ONLY IN THE 90S. A FEW ISOLATED
THUNDERSTORMS MAY DEVELOP DURING THE LATE AFTERNOON OVER YUMA AND KIT
CARSON COUNTIES AS SURFACE CONVERGENCE DEVELOPS UNDERNEATH A SHORT
WAVE TROUGH ROUNDING THE UPPER LEVEL RIDGE. ANY STORM ACTIVITY MAY
PUSH EAST INTO PARTS OF SOUTHWEST NEBRASKA AND NORTHWEST KANSAS.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1241 PM MDT WED JUL 25 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE TROUGH AXIS
CURRENTLY EXTENDING ACROSS NEBRASKA PANHANDLE SOUTH ALONG KS/CO
STATE LINE...AND THEN ACROSS OK/TX PANHANDLE. WV IMAGERY SHOWS
PLUME OF MID LEVEL MOISTURE EXTENDING NORTH ON LEE SIDE OF ROCKIES
ALONG WESTERN EDGE OF TROUGH AXIS. ANOTHER SHORTWAVE TROUGH IS
CURRENTLY OVER CENTRAL WY AND SHOULD MOVE EAST INTO NEBRASKA BY
THIS EVENING. AT THE SURFACE THE COLD FRONT HAS STALLED JUST
SOUTHEAST OF OUR CWA. CLOUD COVER AND CONVECTION HAVE BEEN SLOW TO
DEVELOP MUCH FURTHER SOUTH THAN THE EXTREME NW PART OF CWA.
AS THE SHORTWAVE OVER CENTRAL WY MOVES EAST GUIDANCE CONTINUES TO
SHOW LARGE SCALE ASCENT INCREASING ACROSS THE EASTERN HALF OF THE
CWA IN PROXIMITY OF FRONT. AT THIS TIME LATEST HRRR AND RUC WOULD
SUPPORT SCATTERED THUNDERSTORMS FORMING GENERALLY EAST OF GOODLAND
AND THEN INCREASING IN COVERAGE THROUGH 00Z AS THEY MOVE
EASTWARD...QUICKLY ENDING OVER OUR CWA THIS EVENING. NAM CONTINUES
TO SHOW ISOLATED ACTIVITY FURTHER WEST ASSOCIATED WITH ELEVATED
CAPE AND H7 FRONTOGENESIS THROUGH THE OVERNIGHT PERIOD. CONFIDENCE
IS STILL TOO LOW TO INCLUDE ANY THUNDERSTORMS BEYOND THIS EVENING
WITH LARGE SCALE SUBSIDENCE AND SURFACE HIGH PRESSURE QUICKLY
BUILDING OVER THE CWA. I LEFT PATCHY FOG MENTION IN FORECAST OVER
EASTERN LOCATIONS...WITH CLAM WINDS AND STABLE AIR MASS SUPPORTING
RADIATIVE FOG DEVELOPMENT. GUIDANCE REALLY HAS NOT PICKED UP ON THIS
YET...SO I HAVE LEFT FOG COVERAGE LIMITED TO PATCHY.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 246 PM MDT WED JUL 25 2012
HIGH PRESSURE MOVES INTO THE PLAINS STATES AT THE SURFACE THURSDAY
AND FRIDAY AS THE UPPER RIDGE AMPLIFIES OVER THE INTERMOUNTAIN
WEST AND MOVES EAST OVER THE ROCKIES. PRECIPITATION CHANCES ARE
MINIMAL ON THURSDAY AND THURSDAY NIGHT AS A RESULT. BY FRIDAY
EVENING THE SURFACE HIGH MOVES FAR ENOUGH TO THE EAST WITH A LEE
TROUGH DEEPENING IN THE VICINITY OF THE FAR EASTERN COLORADO
BORDER TO FORM A CONVERGENCE AREA OVER THE WESTERN PORTION OF THE
FORECAST AREA AS A SHORT WAVE TROUGH IN THE UPPER LEVEL FLOW MOVES
OVER THROUGH THE TOP OF THE RIDGE AND CLIPS THE NORTHERN SECTIONS
OF THE FORECAST AREA FRIDAY NIGHT. THIS SETUP WILL BRING A BETTER
CHANCE OF THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. SEVERAL
ADDITIONAL SHORT WAVE TROUGHS MAKE THEIR WAY AROUND THE UPPER
RIDGE AND CLIP THE FORECAST AREA FROM SATURDAY THROUGH TUESDAY.
WITH A SURFACE TROUGH ALSO REMAINING OVER MAINLY THE WESTERN
PORTION OF THE FORECAST AREA DURING THIS TIME...THEREFORE EXPECT
TEMPERATURES TO REMAIN VERY WARM WITH ADDITIONAL DIURNALLY DRIVEN
ISOLATED TO SCATTERED THUNDERSTORMS MAINLY OVER THE WESTERN
PORTIONS OF THE FORECAST AREA. BY THE MIDDLE OF NEXT
WEEK...CURRENT INDICATIONS ARE THAT THE UPPER RIDGE WILL AMPLIFY
FURTHER AND MOVE MORE OVER THE PLAINS STATES...SENDING THE SHORT
WAVE IMPULSES FURTHER NORTH THROUGH THE NORTHERN PLAINS AND
POSSIBLY DECREASING THE POSSIBILITY OF PRECIPITATION ACROSS THE
CENTRAL HIGH PLAINS REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1109 PM MDT WED JUL 25 2012
VFR CONDITIONS ARE FORECAST FOR THE 6Z TAFS. WINDS WILL REMAIN
LIGHT THROUGH THE PERIOD AS THE UPPER LEVEL HIGH PRESSURE
STRENGTHENS OVER THE TRI-STATE AREA. WITH MOISTURE...LIFT AND
INSTABILITY REMAINING WELL WEST OF THE TAF SITES...AM NOT
EXPECTING ANY THUNDERSTORMS TO MOVE NEAR THE SITES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1044 PM MDT WED JUL 25 2012
.UPDATE...
ISSUED AT 1036 PM MDT WED JUL 25 2012
SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OVER THE NORTON AND
HILL CITY AREA THIS EVENING. AM EXPECTING THE ACTIVITY TO MOVE
EAST IN THE NEXT HOUR OR SO AS THE LIFT BEHIND THE COLD FRONT FROM
AN UPPER LEVEL SHORT WAVE TROUGH MOVES SOUTHEAST.
FOR THURSDAY TEMPERATURES WILL CONTINUE TO BE COOLER THAN WHAT WE
HAVE HAD...WITH HIGHS ONLY IN THE 90S. A FEW ISOLATED
THUNDERSTORMS MAY DEVELOP DURING THE LATE AFTERNOON OVER YUMA AND KIT
CARSON COUNTIES AS SURFACE CONVERGENCE DEVELOPS UNDERNEATH A SHORT
WAVE TROUGH ROUNDING THE UPPER LEVEL RIDGE. ANY STORM ACTIVITY MAY
PUSH EAST INTO PARTS OF SOUTHWEST NEBRASKA AND NORTHWEST KANSAS.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1241 PM MDT WED JUL 25 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE TROUGH AXIS
CURRENTLY EXTENDING ACROSS NEBRASKA PANHANDLE SOUTH ALONG KS/CO
STATE LINE...AND THEN ACROSS OK/TX PANHANDLE. WV IMAGERY SHOWS
PLUME OF MID LEVEL MOISTURE EXTENDING NORTH ON LEE SIDE OF ROCKIES
ALONG WESTERN EDGE OF TROUGH AXIS. ANOTHER SHORTWAVE TROUGH IS
CURRENTLY OVER CENTRAL WY AND SHOULD MOVE EAST INTO NEBRASKA BY
THIS EVENING. AT THE SURFACE THE COLD FRONT HAS STALLED JUST
SOUTHEAST OF OUR CWA. CLOUD COVER AND CONVECTION HAVE BEEN SLOW TO
DEVELOP MUCH FURTHER SOUTH THAN THE EXTREME NW PART OF CWA.
AS THE SHORTWAVE OVER CENTRAL WY MOVES EAST GUIDANCE CONTINUES TO
SHOW LARGE SCALE ASCENT INCREASING ACROSS THE EASTERN HALF OF THE
CWA IN PROXIMITY OF FRONT. AT THIS TIME LATEST HRRR AND RUC WOULD
SUPPORT SCATTERED THUNDERSTORMS FORMING GENERALLY EAST OF GOODLAND
AND THEN INCREASING IN COVERAGE THROUGH 00Z AS THEY MOVE
EASTWARD...QUICKLY ENDING OVER OUR CWA THIS EVENING. NAM CONTINUES
TO SHOW ISOLATED ACTIVITY FURTHER WEST ASSOCIATED WITH ELEVATED
CAPE AND H7 FRONTOGENESIS THROUGH THE OVERNIGHT PERIOD. CONFIDENCE
IS STILL TOO LOW TO INCLUDE ANY THUNDERSTORMS BEYOND THIS EVENING
WITH LARGE SCALE SUBSIDENCE AND SURFACE HIGH PRESSURE QUICKLY
BUILDING OVER THE CWA. I LEFT PATCHY FOG MENTION IN FORECAST OVER
EASTERN LOCATIONS...WITH CLAM WINDS AND STABLE AIR MASS SUPPORTING
RADIATIVE FOG DEVELOPMENT. GUIDANCE REALLY HAS NOT PICKED UP ON THIS
YET...SO I HAVE LEFT FOG COVERAGE LIMITED TO PATCHY.
.LONG TERM...(THURSDAY THROUGH WEDNESDAY)
ISSUED AT 246 PM MDT WED JUL 25 2012
HIGH PRESSURE MOVES INTO THE PLAINS STATES AT THE SURFACE THURSDAY
AND FRIDAY AS THE UPPER RIDGE AMPLIFIES OVER THE INTERMOUNTAIN
WEST AND MOVES EAST OVER THE ROCKIES. PRECIPITATION CHANCES ARE
MINIMAL ON THURSDAY AND THURSDAY NIGHT AS A RESULT. BY FRIDAY
EVENING THE SURFACE HIGH MOVES FAR ENOUGH TO THE EAST WITH A LEE
TROUGH DEEPENING IN THE VICINITY OF THE FAR EASTERN COLORADO
BORDER TO FORM A CONVERGENCE AREA OVER THE WESTERN PORTION OF THE
FORECAST AREA AS A SHORT WAVE TROUGH IN THE UPPER LEVEL FLOW MOVES
OVER THROUGH THE TOP OF THE RIDGE AND CLIPS THE NORTHERN SECTIONS
OF THE FORECAST AREA FRIDAY NIGHT. THIS SETUP WILL BRING A BETTER
CHANCE OF THUNDERSTORMS FRIDAY AFTERNOON AND EVENING. SEVERAL
ADDITIONAL SHORT WAVE TROUGHS MAKE THEIR WAY AROUND THE UPPER
RIDGE AND CLIP THE FORECAST AREA FROM SATURDAY THROUGH TUESDAY.
WITH A SURFACE TROUGH ALSO REMAINING OVER MAINLY THE WESTERN
PORTION OF THE FORECAST AREA DURING THIS TIME...THEREFORE EXPECT
TEMPERATURES TO REMAIN VERY WARM WITH ADDITIONAL DIURNALLY DRIVEN
ISOLATED TO SCATTERED THUNDERSTORMS MAINLY OVER THE WESTERN
PORTIONS OF THE FORECAST AREA. BY THE MIDDLE OF NEXT
WEEK...CURRENT INDICATIONS ARE THAT THE UPPER RIDGE WILL AMPLIFY
FURTHER AND MOVE MORE OVER THE PLAINS STATES...SENDING THE SHORT
WAVE IMPULSES FURTHER NORTH THROUGH THE NORTHERN PLAINS AND
POSSIBLY DECREASING THE POSSIBILITY OF PRECIPITATION ACROSS THE
CENTRAL HIGH PLAINS REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 508 PM MDT WED JUL 25 2012
VFR CONDITIONS ARE FORECAST FOR THE 0Z TAFS. COLD FRONT CURRENTLY
RUNNING FROM JUST WEST OF NORTON SOUTHWEST TO NEAR RUSSELL SPRINGS
WILL DRIFT EAST QUITE SLOWLY FOR THE NEXT COUPLE OF HOURS. MEANWHILE AN
UPPER LEVEL SHORT WAVE TROUGH CURRENTLY SPARKING SCATTERED STORMS
OVER EASTERN COLORADO WILL MOVE THROUGH THE TRI- STATE AREA OVER THE
NEXT COUPLE OF HOURS...POSSIBLY BRINGING SOME ISOLATED TO
SCATTERED STORMS WITH IT. WILL LEAVE A VCTS MENTION IN THE TAFS
BUT WILL NOT INCLUDE A TEMPO GROUP AS AM NOT CONFIDENT ENOUGH THAT
STORMS WILL MOVE OVER ANY OF THE TAF SITES. THE UPPER LEVEL TROUGH
WILL MOVE OUT OF THE AREA DURING THE MID TO LATE EVENING BRINGING
PRECIP. CHANCES TO AN END.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JTL
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
330 PM EDT THU JUL 26 2012
.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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON AND INTO THE
EVENING...THOUGH THERE WILL BE WIND GUSTS TO AROUND 20 KNOTS FROM THE
SOUTHWEST. THUNDERSTORMS ARE EXPECTED TO MOVE INTO THE NORTHERN PART OF
THE FORECAST AREA AROUND 01Z IN ADVANCE OF AN APPROACHING COLD FRONT.
THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE FORECAST AREA
DURING THE OVERNIGHT PERIOD...WITH CONDITIONS TO MVFR OR IFR. ONCE
THE THUNDERSTORMS PASS EXPECT IFR TO MVFR CONDITIONS IN FOG AND LOW
CLOUD TO PERSIST INTO THE DAY ON FRIDAY. CONDITIONS WILL IMPROVE BACK
TO VFR DURING THE DAY FRIDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR KYZ044-050>052.
&&
$$
SHORT TERM...SBH
LONG TERM....JP
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
300 PM EDT THU JUL 26 2012
.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 300 PM EDT THU JUL 26 2012
LONG TERM DISCUSSION WILL FOLLOW SHORTLY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON AND INTO THE
EVENING...THOUGH THERE WILL BE WIND GUSTS TO AROUND 20 KNOTS FROM THE
SOUTHWEST. THUNDERSTORMS ARE EXPECTED TO MOVE INTO THE NORTHERN PART OF
THE FORECAST AREA AROUND 01Z IN ADVANCE OF AN APPROACHING COLD FRONT.
THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE FORECAST AREA
DURING THE OVERNIGHT PERIOD...WITH CONDITIONS TO MVFR OR IFR. ONCE
THE THUNDERSTORMS PASS EXPECT IFR TO MVFR CONDITIONS IN FOG AND LOW
CLOUD TO PERSIST INTO THE DAY ON FRIDAY. CONDITIONS WILL IMPROVE BACK
TO VFR DURING THE DAY FRIDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR KYZ044-050>052.
&&
$$
SHORT TERM...SBH
LONG TERM....
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
146 PM EDT THU JUL 26 2012
.UPDATE...
ISSUED AT 145 PM EDT THU JUL 26 2012
HAVE UPDATED NDFD FOR LATEST NEAR TERM TRENDS AND OBSERVATIONS. CAP
LOOKS TO INHIBIT CONVECTION FOR THE NEXT SEVERAL HOURS...BUT CAP
SHOULD ERODE BY LATE AFTERNOON. PAST SEVERAL RUNS OF THE HRRR HAVE
BEEN CONSISTENT WITH NO CONVECTION INITIATING IN OUR AREA THIS
AFTERNOON. IT HAS ALSO BEEN CONSISTENT WITH CONVECTION MOVING INTO
THE THE FAR NORTHERN PART OF THE FORECAST AREA AROUND 01Z. WITH BEST
DYNAMICS TO OUR NORTH AND LOSS OF DAYTIME HEATING NOT REAL CONFIDENT
IN SEVERE THREAT FOR THE OVERNIGHT PERIOD. STILL APPEARS THAT THE
BEST CHANCE FOR SEVERE STORMS WILL BE FAR NORTH WITH SHARP DECLINE IN
SEVERE THREAT THE FURTHER SOUTH YOU GO.
UPDATE ISSUED AT 1052 AM EDT THU JUL 26 2012
DEWPOINT POOLING IN THE FAR NORTH WILL LEAD TO HEAT INDEX VALUES NEAR
105 THIS AFTERNOON. HAVE ISSUED A HEAT ADVISORY FOR THE FAR NORTH
THROUGH 7 PM THIS EVENING. THIS WILL ALIGN WELL WITH NEIGHBORING HEAT
ADVISORIES AND WARNINGS.
12Z NAM POINTING TOWARDS PRIMARY THUNDERSTORM CHANCE DURING THE
OVERNIGHT PERIOD. THIS IS IN GOOD AGREEMENT WITH CURRENT FORECAST. THE
HRRR CONTINUES TO SHOW THE POTENTIAL FOR SCATTERED CONVECTION THIS
AFTERNOON...BUT WITH THE PRIMARY THUNDERSTORM THREAT BEGINNING AFTER
23Z.
SEVERE THREAT FOR OUR AREA LOOKS TO BE PRIMARILY THIS EVENING...WITH
CONVECTION WEAKENING DURING THE OVERNIGHT PERIOD. HAVE UPDATED
NDFD...HWO AND ZFP.
UPDATE ISSUED AT 710 AM EDT THU JUL 26 2012
JUST A QUICK UPDATE TO ESTABLISH TEMPS AND DEW PTS HEADING INTO THE
DAY. SOME MINOR ADJUSTMENTS WERE MADE IN THE BEGINNING OF THE LONG
TERM...MAINLY JUST TO MOVE POPS OUT A LITTLE QUICKER. WILL FRESHEN UP
THE ZFP. UPDATED GRIDS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 345 AM EDT THU JUL 26 2012
SFC ANALYSIS THIS MORNING SHOWS A LOW PRESSURE SYSTEM MOVING THROUGH
THE GREAT LAKES WITH A TRAILING COLD FRONT STRETCHED BACK ACROSS THE
MID MS VALLEY INTO THE SRN PLAINS. CONVECTION HAS BEEN RATHER
VIGOROUS IN THE VICINITY OF THE FRONT WHERE MOISTURE HAS POOLED ALONG
A PRE FRONTAL TROF. SAT IMAGERY THIS MORNING ALSO REVEALS A GOOD FETCH
OF MOISTURE FROM THE GULF OF MEXICO WITH PWATS AROUND 2 INCHES
ADVECTING INTO THE OHIO VALLEY ON A 35 KT LLJ EVIDENT ON THE JKL VAD
WIND PROFILE.
EXPECTING FOR THE MOST PART A BREEZY DAY ACROSS THE AREA AS THE
GRADIENT STRENGTHENS AHEAD OF THE APPROACHING FRONT. ONCE THE
NOCTURNAL INVERSION BREAKS THIS MORNING...LLJ MOMENTUM SHOULD BE ABLE
TO MIX DOWN TO THE SFC WITH SWLY WINDS GUSTING AROUND 25 KTS THROUGH
THE AFTERNOON...BOOSTING TEMPS INTO THE LOWER TO MID 90S. DEW PTS ARE
FCST TO SLIDE FROM THE LOWER/MID 70S INTO THE UPPER 60S THROUGH THE
DAY AS WINDS KEEP THINGS RELATIVELY MIXED...AND THIS SHOULD PREVENT
ANY HEAT ADVISORY CRITERIA FROM BEING REACHED TODAY...THOUGH WOULD
NOT BE TOO SURPRISED TO SEE A FEW LOCAL HEAT INDICES SNEAK INTO THE
TRIPLE DIGITS FOR AN HOUR OR SO THIS AFTERNOON.
CURRENT PROGS ARE GENERALLY IN GOOD AGREEMENT WITH BRINGING
CONVECTION ALONG THE PRE FRONTAL TROF INTO THE AREA THIS EVENING AND
WITH A RELATIVELY GOOD CONSENSUS CAN SEE LITTLE REASON TO ARGUE WITH
TIMING. FCST SOUNDINGS SHOW MODERATE INSTABILITY LINGERING THROUGH
THE OVERNIGHT HOURS AS THE TROF PUSHES THROUGH THE AREA...AND WILL
NOT RULE OUT ONE OR TWO STRONGER STORMS OVERNIGHT...ESPECIALLY IN THE
NORTH WHERE BETTER UPPER LEVEL DYNAMICS WILL RESIDE. THE MAIN
CONCERNS WILL BE DAMAGING WINDS AND LOCALIZED SHORT TERM HYDRO ISSUES
GIVEN THE RECENT RAINS...AND ANOMALOUS PWATS...AND A GOOD POTENTIAL
FOR TRAINING STORMS.
WE SHOULD SEE A BIT OF A LULL AT SOME POINT DURING THE DAY ON FRIDAY
AS THE TROF PUSHES EAST...BUT SOME SCATTERED CONVECTION WILL STILL BE
POSSIBLE THROUGH THE DAY AS THE FRONT BEGINS TO PUSH THROUGH THE
AREA. FCST SOUNDINGS SUGGEST THE PRIMARY THREAT WITH ANY OF THE
STRONGER TSTMS ON FRIDAY WOULD AGAIN BE DAMAGING WINDS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 415 AM EDT THU JUL 26 2012
A MID/UPPER LEVEL TROUGH WILL BE OVER THE REGION AT THE START OF THE
PERIOD...WITH ITS ASSOCIATED COLD FRONT IN THE PROCESS OF JUMPING
THE APPALACHIANS. DRYING SHOULD BE UNDERWAY BY FRIDAY NIGHT...
ESPECIALLY IN THE MID/UPPER LEVELS...AS THE UPPER LEVEL SUPPORT FOR
PRECIP MOVES TO OUR SOUTHEAST. WILL LOOK FOR DRY WEATHER ON FRIDAY
NIGHT. SURFACE HIGH PRESSURE BEHIND THE COLD FRONT WILL THEN MOVE
EASTWARD ACROSS THE MIDWEST DURING THE WEEKEND...BRINGING US MAINLY
CLEAR SKIES AND SLIGHTLY LESS HUMID AIR.
THE HIGH PRESSURE WILL WEAKEN AND MOVE EAST OFF THE COAST ON
MONDAY...AS ANOTHER COLD FRONT HEADS SLOWLY SOUTHEAST THROUGH THE
MIDWEST. THE WIND FLOW BETWEEN THE COLD FRONT AND THE HIGH WILL
CARRY MOISTURE BACK INTO THE LOCAL AREA...WITH A RETURN OF PRECIP
POTENTIAL FROM MONDAY NIGHT FORWARD. THE HIGHEST POP WILL BE WITH
PEAK HEATING JUST AHEAD OF THE COLD FRONT ON TUESDAY. EVEN THOUGH THE
DEEPEST MOISTURE APPEARS TO SHIFT SOUTHEAST ON WEDNESDAY AND THE
SURFACE FRONT BEGINS TO TRANSITION ACROSS THE MOUNTAINS...THE SURFACE
AIR MASS MAY BE SLOWER AND MORE DIFFICULT TO CHANGE...AND SHOWERS AND
THUNDERSTORMS OF LESSER EXTENT ARE STILL A POSSIBILITY ON WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 145 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL THROUGH THE AFTERNOON AND INTO THE
EVENING...THOUGH THERE WILL BE WIND GUSTS TO AROUND 20 KNOTS FROM THE
SOUTHWEST. THUNDERSTORMS ARE EXPECTED TO MOVE INTO THE NORTHERN PART OF
THE FORECAST AREA AROUND 01Z IN ADVANCE OF AN APPROACHING COLD FRONT.
THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE FORECAST AREA
DURING THE OVERNIGHT PERIOD...WITH CONDITIONS TO MVFR OR IFR. ONCE
THE THUNDERSTORMS PASS EXPECT IFR TO MVFR CONDITIONS IN FOG AND LOW
CLOUD TO PERSIST INTO THE DAY ON FRIDAY. CONDITIONS WILL IMPROVE BACK
TO VFR DURING THE DAY FRIDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR KYZ044-050>052.
&&
$$
UPDATE...SBH
SHORT TERM...MB
LONG TERM....HAL
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
426 PM EDT THU JUL 26 2012
.SYNOPSIS...
A SQUALL LINE OF SEVERE THUNDERSTORMS WILL MOVE THROUGH WITH
DAMAGING WIND, HEAVY RAIN, HAIL, AND LOTS OF LIGHTNING. THERE
WILL STILL BE SCATTERED THUNDERSTORMS AROUND THE UPPER OHIO VALLEY
UNTIL SATURDAY NIGHT, WHEN A SOUTHBOUND COLD FRONT BRINGS LOWER
HUMIDITY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
UPDATE MADE TO DROP HEAT ADVISORY WHERE THUNDERSTORMS HAVE COOLED
TEMPERATURES DOWN.
THE MAIN CONCERN THROUGH EVENING IS STILL THE PASSAGE OF A SQUALL
LINE OF SEVERE THUNDERSTORMS WITH DAMAGING WIND, HAIL, HEAVY RAIN,
AND LOTS OF LIGHTNING.
A FLASH FLOOD WATCH HAS BEEN ISSUED AS THE THUNDERSTORMS WITH
HEAVY RAIN WILL BE MOVING THROUGH URBAN AREAS, DURING EVENING
COMMUTE AND EVENING HOURS. IT MAY HAVE TO BE EXTENDED AND EXPANDED
IF LINES OF THUNDERSTORMS CONTINUE TO DEVELOP FARTHER WEST.
RAIN AMOUNTS OF MORE THAN 1.5 INCHES IN LESS THAN 3 HOURS CAN
CAUSE FLASH FLOODING IN URBAN AREAS AND WHERE DRAINAGE IS POOR. IF
MORE THAN 2.5 INCHES OCCUR, SERIOUS FLASH FLOODING CAN DEVELOP.
RECENT HRRR MODEL OUTPUT, ALONG WITH 12Z WRF-NMM MODEL OUTPUT,
INDEED SHOWS THERE CAN BE TWO OR THREE LINES OF THUNDERSTORMS.
HOWEVER, OUR OPINION IS THAT THE INITIAL LINE WILL HAVE THE
HIGHEST WIND GUSTS, WHILE THE LATTER LINES CAN CONTRIBUTE TO THE
RAINFALL TOTALS. WILL MONITOR AS MAY HAVE TO EXPAND THE AREA OF
CURRENT FLASH FLOOD WATCH.
LATEST TIMING OF STORMS
INDIANA-MORGANTOWN WV/ KIDI-KMGW/: 5-6PM.
OAKLAND MD/ K2G4/: 6-7PM.
SECOND LINE OF STORMS MAY AFFECT NEW PHILADELPHIA AND ZANESVILLE
AREA BETWEEN 5 AND 6 PM.
CONSIDERING THE TIMINGS, THE STORMS CAN IMPACT EVENING COMMUTERS
AND THOSE PARTICIPATING IN OUTDOOR EVENING ACTIVITIES.
CONTINUE TO EXPECT SCATTERED THUNDERSTORMS LATER TONIGHT IN THE
WAKE OF THESE LINES OF STORMS. PATCHY FOG MAY ALSO OCCUR.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM 12Z 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. SUNDAY SHOULD BE
DRY.
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 MONDAY NIGHT INTO
THURSDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
WILL CONTINUE TO AMEND TAFS, PERTAINING TO IFR RESTRICTIONS AND
POSSIBLE WIND GUSTS OVER 50 KTS, BASED ON MOVEMENT AND
DEVELOPMENT OF THE LINES OF THUNDERSTORMS THROUGH 02Z.
EXPECT COVERAGE OF THUNDERSTORMS TO DECREASE TO SCATTERED BY LATE
TONIGHT. POST-STORM FOG AND STRATUS MAY ALSO CAUSE A SHORT PERIOD OF
IFR RESTRICTIONS MAINLY FROM 08Z TO 12Z FRIDAY. SCATTERED SHOWERS
AND STORMS WITH OCCASIONAL RESTRICTIONS WILL CONTINUE OVER THE
REGION FRIDAY.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
SCATTERED THUNDERSTORMS AND THE POTENTIAL FOR RESTRICTIONS WILL
REMAIN THROUGH SATURDAY AS AN UPPER TROUGH AND A SECONDARY FRONT
PUSH ACROSS THE UPPER OHIO VALLEY. DRY VFR CONDITIONS ARE EXPECTED
UNDER SURFACE HIGH PRESSURE SUNDAY AND MONDAY. INCREASING MOISTURE
ASSOCIATED WITH AN EAST COAST LOW WILL FUEL SCATTERED SHOWERS AND
THUNDERSTORMS TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR OHZ041-050-
059-069.
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ013>016-
020>023-029-031-073>076.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ029-031-073-
075.
WV...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR WVZ001>004-
012-021-022.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ012-021-022.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
327 PM EDT THU JUL 26 2012
.SYNOPSIS...
A SQUALL LINE OF SEVERE THUNDERSTORMS WILL MOVE THROUGH WITH
DAMAGING WIND, HEAVY RAIN, HAIL, AND LOTS OF LIGHTNING. THERE
WILL STILL BE SCATTERED THUNDERSTORMS AROUND THE UPPER OHIO VALLEY
UNTIL SATURDAY NIGHT, WHEN A SOUTHBOUND COLD FRONT BRINGS LOWER
HUMIDITY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE MAIN CONCERN THROUGH EVENING WILL BE THE PASSAGE OF A SQUALL LINE
OF SEVERE THUNDERSTORMS WITH DAMAGING WIND, HAIL, HEAVY RAIN, AND
LOTS OF LIGHTNING.
SPC HAS UPGRADED THE ENTIRE AREA TO SEVERE
THUNDERSTORM WATCH UNTIL 10 PM, WITH WIDESPREAD DAMAGING
THUNDERSTORMS THE MOST PROBABLE SEVERE THUNDERSTORM HAZARD. WFO
PITTSBURGH HAS BEEN ISSUING SEVERE THUNDERSTORM WARNINGS BASED ON
RECENT RADAR DEVELOPMENTS.
A FLASH FLOOD WATCH HAS BEEN ISSUED AS THE THUNDERSTORMS WITH
HEAVY RAIN WILL BE MOVING THROUGH URBAN AREAS, DURING EVENING
COMMUTE AND EVENING HOURS. IT MAY HAVE TO BE EXTENDED AND EXPANDED
IF LINES OF THUNDERSTORMS CONTINUE TO DEVELOP FARTHER WEST.
HPC HAS HAD A SLIGHT RISK OF EXCESSIVE RAINFALL. RAIN AMOUNTS OF
MORE THAN 1.5 INCHES IN LESS THAN 3 HOURS CAN CAUSE FLASH FLOODING
IN URBAN AREAS AND WHERE DRAINAGE IS POOR. IF MORE THAN 2.5 INCHES
OCCUR, SERIOUS FLASH FLOODING CAN DEVELOP.
RECENT HRRR MODEL OUTPUT, ALONG WITH 12Z WRF-NMM MODEL OUTPUT,
INDEED SHOWS THERE CAN BE TWO OR THREE LINES OF THUNDERSTORMS.
HOWEVER, OUR OPINION IS THAT THE INITIAL LINE WILL HAVE THE
HIGHEST WIND GUSTS, WHILE THE LATTER LINES CAN CONTRIBUTE TO THE
DUBOIS-PITTSBURGH PA-WHEELING WV/ KDUJ-KPIT-KHLG/: 4-5PM.
INDIANA-MORGANTOWN WV/ KIDI-KMGW/: 4-6PM.
OAKLAND MD/ K2G4/: 5-7 PM.
CONSIDERING THE TIMINGS, THE STORMS CAN IMPACT EVENING COMMUTERS
AND THOSE PARTICIPATING IN OUTDOOR EVENING ACTIVITIES.
CONTINUE TO EXPECT SCATTERED THUNDERSTORMS LATER TONIGHT IN THE
WAKE OF THESE LINES OF STORMS. PATCHY FOG MAY ALSO OCCUR.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM 12Z 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. SUNDAY SHOULD BE
DRY.
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 MONDAY NIGHT INTO
THURSDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
WILL CONTINUE TO AMEND TAFS, PERTAINING TO IFR RESTRICTIONS AND
POSSIBLE WIND GUSTS OVER 50 KTS, BASED ON MOVEMENT AND
DEVELOPMENT OF THE LINES OF THUNDERSTORMS THROUGH 02Z.
EXPECT COVERAGE OF THUNDERSTORMS TO DECREASE TO SCATTERED BY LATE
TONIGHT. POST-STORM FOG AND STRATUS MAY ALSO CAUSE A SHORT PERIOD OF
IFR RESTRICTIONS MAINLY FROM 08Z TO 12Z FRIDAY. SCATTERED SHOWERS
AND STORMS WITH OCCASIONAL RESTRICTIONS WILL CONTINUE OVER THE
REGION FRIDAY.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
SCATTERED THUNDERSTORMS AND THE POTENTIAL FOR RESTRICTIONS WILL
REMAIN THROUGH SATURDAY AS AN UPPER TROUGH AND A SECONDARY FRONT
PUSH ACROSS THE UPPER OHIO VALLEY. DRY VFR CONDITIONS ARE EXPECTED
UNDER SURFACE HIGH PRESSURE SUNDAY AND MONDAY. INCREASING MOISTURE
ASSOCIATED WITH AN EAST COAST LOW WILL FUEL SCATTERED SHOWERS AND
THUNDERSTORMS TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ039>041-
048>050-057>059-068-069.
FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR OHZ041-050-
059-069.
PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ020-021-029-
031-073-075.
FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ013>016-
020>023-029-031-073>076.
WV...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ001>004-012-
021-022.
FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR WVZ001>004-
012-021-022.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
125 PM EDT THU JUL 26 2012
.SYNOPSIS...
EXPECT HOT AND HUMID CONDITIONS THIS AFTERNOON, UNTIL A SQUALL
LINE OF SEVERE THUNDERSTORMS MOVES THROUGH WITH DAMAGING WIND,
HAIL, HEAVY RAIN, AND LOTS OF LIGHTNING. THERE WILL STILL BE
SCATTERED THUNDERSTORMS AROUND THE UPPER OHIO VALLEY UNTIL
SATURDAY NIGHT, WHEN A SOUTHBOUND COLD FRONT BRINGS LOWER
HUMIDITY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN CONCERN THROUGH EVENING WILL BE THE PASSAGE OF A SQUALL LINE
OF SEVERE THUNDERSTORMS WITH DAMAGING WIND, HAIL, HEAVY RAIN, AND
LOTS OF LIGHTNING. SPC HAS UPGRADED THE ENTIRE AREA TO SEVERE
THUNDERSTORM WATCH UNTIL 10 PM, WITH WIDESPREAD DAMAGING
THUNDERSTORMS THE MOST PROBABLE SEVERE THUNDERSTORM HAZARD.
HPC HAS JOINED IN WITH A SLIGHT RISK OF EXCESSIVE RAINFALL. RAIN
AMOUNTS OF MORE THAN 1.5 INCHES IN LESS THAN 3 HOURS CAN CAUSE
FLASH FLOODING IN URBAN AREAS AND WHERE DRAINAGE IS POOR. AM
CONSIDERING FLASH FLOOD WATCH, BUT WANT TO SEE IF REPEAT
THUNDERSTORMS WILL OCCUR.
CONCUR WITH THESE FORECASTS BASED ON RECENT SREF AND RAP INSTABILITY
AND VERTICAL SHEAR PROFILES.
RECENT RADAR DATA SHOWS THE INITIAL LINE OF SEVERE THUNDERSTORMS
HAS DEVELOPED ACROSS NORTHWEST PA AND NORTHERN OH.
SATELLITE DATA SHOWS A BAND OF CUMULUS HAS DEVELOPED FROM
JOHNSTOWN PA TO MORGANTOWN WV TO PARKERSBURG WV /KJST-KMGW-KPKB,
BUT SO FAR THE CONVECTION HAS BEEN CAPPED. BUT WILL HAS TO BE MONITORED.
RECENT HRRR MODEL OUTPUT, ALONG WITH 12Z WRF-NMM MODEL OUTPUT,
THERE CAN BE TWO OR THREE LINES OF THUNDERSTORMS. HOWEVER, OUR
OPINION IS THAT THE INITIAL LINE WILL HAVE THE HIGHEST WIND GUSTS.
SO FOR CONTINUITY, HAVE MAINTAINED THE FOLLOWING TIMING OF SQUALL
LINE ONSET.
FRANKLIN PA TO ZANESVILLE OH/ KFKL-KZZV/: 2-4PM.
DUBOIS-PITTSBURGH PA-WHEELING WV/ KDUJ-KPIT-KHLG/: 3-5PM.
INDIANA-MORGANTOWN WV/ KIDI-KMGW/: 4-6PM.
OAKLAND MD/ K2G4/: 6 PM.
CONSIDERING THE TIMINGS, THE STORMS CAN IMPACT EVENING COMMUTERS
AND THOSE PARTICIPATING IN OUTDOOR EVENING ACTIVITIES.
CONTINUE TO EXPECT SCATTERED THUNDERSTORMS LATER TONIGHT IN THE
WAKE OF THESE LINES OF STORMS. PATCHY FOG MAY ALSO OCCUR.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM 12Z 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. SUNDAY SHOULD BE
DRY.
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 WEDNESDAY/...
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 MONDAY NIGHT INTO
WEDNESDAY AND THURSDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
EXPECT LINES OF THUNDERSTORMS TO DEVELOP ALONG OUTFLOW BOUNDARIES
FROM EARLIER CONVECTION...AS WELL AS ALONG AND AHEAD OF A COLD FRONT
MOVING INTO THE REGION. CONFIDENCE IS HIGH THAT MOST TERMINALS WILL
EXPERIENCE THUNDERSTORMS WITH COVERAGE INCREASING FROM NORTHWEST TO
SOUTHEAST AS THE AFTERNOON PROGRESSES. IFR RESTRICTIONS IN HEAVY
RAIN CAN BE ANTICIPATED AND SFC GUSTS IN EXCESS OF 50KT ARE POSSIBLE.
EXPECT COVERAGE OF THUNDERSTORMS TO DECREASE TO SCATTERED BY LATE
TONIGHT. POST-STORM FOG AND STRATUS MAY ALSO CAUSE A SHORT PERIOD OF
IFR RESTRICTIONS MAINLY FROM 08Z TO 12Z FRIDAY. SCATTERED SHOWERS
AND STORMS WITH OCCASIONAL RESTRICTIONS WILL CONTINUE OVER THE
REGION FRIDAY.
OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY...
SCATTERED THUNDERSTORMS AND THE POTENTIAL FOR RESTRICTIONS WILL
REMAIN THROUGH SATURDAY AS AN UPPER TROUGH AND A SECONDARY FRONT
PUSH ACROSS THE UPPER OHIO VALLEY. DRY VFR CONDITIONS ARE EXPECTED
UNDER SURFACE HIGH PRESSURE SUNDAY AND MONDAY. INCREASING MOISTURE
ASSOCIATED WITH AN EAST COAST LOW WILL FUEL SCATTERED SHOWERS AND
THUNDERSTORMS TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ039>041-
048>050-057>059-068-069.
PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ020-021-029-
031-073-075.
WV...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ001>004-012-
021-022.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1251 PM EDT THU JUL 26 2012
.SYNOPSIS...
EXPECT HOT AND HUMID CONDITIONS THIS AFTERNOON, UNTIL A SQUALL
LINE OF SEVERE THUNDERSTORMS MOVES THROUGH WITH DAMAGING WIND,
HAIL, HEAVY RAIN, AND LOTS OF LIGHTNING. THERE WILL STILL BE
SCATTERED THUNDERSTORMS AROUND THE UPPER OHIO VALLEY UNTIL
SATURDAY NIGHT, WHEN A SOUTHBOUND COLD FRONT BRINGS LOWER
HUMIDITY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN CONCERN THROUGH EVENING WILL BE THE PASSAGE OF A SQUALL LINE
OF SEVERE THUNDERSTORMS WITH DAMAGING WIND, HAIL, HEAVY RAIN, AND
LOTS OF LIGHTNING.
SPC CONTINUES TO PROJECT A MODERATE RISK OF SEVERE THUNDERSTORMS
FOR THE ENTIRE UPPER OHIO VALLEY, WITH WIDESPREAD DAMAGING
THUNDERSTORMS THE MOST PROBABLE SEVERE THUNDERSTORM HAZARD.
HPC HAS JOINED IN WITH A SLIGHT RISK OF EXCESSIVE RAINFALL. RAIN
AMOUNTS OF MORE THAN 1.5 INCHES IN LESS THAN 3 HOURS CAN CAUSE
FLASH FLOODING IN URBAN AREAS AND WHERE DRAINAGE IS POOR.
CONCUR WITH THESE FORECASTS BASED ON RECENT SREF AND RAP INSTABILITY
AND VERTICAL SHEAR PROFILES.
RECENT SATELLITE DATA SHOWS THE LEADING EDGE OF THICKER CLOUDS/
FROM CLEVELAND TO CINCINNATI OHIO /KCLE-KCMH-KCVG/. ALSO A BAND OF
CUMULUS HAS DEVELOPED FROM JOHNSTOWN PA TO MORGANTOWN WV TO
PARKERSBURG WV /KJST-KMGW-KPKB. THE FORMER IS MORE LIKELY WHERE
THE SQUALL LINE WILL FORM, BUT THE LATTER HAS TO BE ALSO MONITORED.
RECENT HRRR MODEL OUTPUT, ALONG WITH 12Z WRF-NMM MODEL OUTPUT,
THERE CAN BE TWO OR THREE LINES OF THUNDERSTORMS. HOWEVER, OUR
OPINION IS THAT THE INITIAL LINE WILL HAVE THE HIGHEST WIND GUSTS.
SO FOR CONTINUITY, HAVE MAINTAINED THE FOLLOWING TIMING OF SQUALL
LINE ONSET.
FRANKLIN PA TO ZANESVILLE OH/ KFKL-KZZV/: 2-4PM.
DUBOIS-PITTSBURGH PA-WHEELING WV/ KDUJ-KPIT-KHLG/: 3-5PM.
INDIANA-MORGANTOWN WV/ KIDI-KMGW/: 4-6PM.
OAKLAND MD/ K2G4/: 6 PM.
CONSIDERING THE TIMINGS, THE STORMS CAN IMPACT EVENING COMMUTERS
AND THOSE PARTICIPATING IN OUTDOOR EVENING ACTIVITIES.
CONTINUE TO EXPECT SCATTERED THUNDERSTORMS LATER TONIGHT IN THE
WAKE OF THESE LINES OF STORMS. PATCHY FOG MAY ALSO OCCUR.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM 12Z 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. SUNDAY SHOULD BE
DRY.
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 WEDNESDAY/...
MEDIUM RANGE MODELS SHOW SURFACE HIGH PRESSURE AND DRY CONDITIONS
FOR MONDAY.
AN UPPER TROUGH IS PROGGED TO REMAIN OVER THE EAST COAST EARLY
NEXT WEEK. MODELS HINT AT A SURFACE LOW MOVING ALONG THE EAST
COAST TUESDAY AND WEDNESDAY. PLAN TO KEEP CHANCE POPS FOR SHOWERS
AND THUNDERSTORMS MONDAY NIGHT THROUGH WEDNESDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE MAIN FORECAST ISSUE WL BE THE DEVELOPMENT AND COVERAGE OF TSRA AS
OUTFLOW FM A GREAT LAKES MCS...AS WELL AS THE CDFNT MOVE TOWARD
THE REGION. CONFIDENCE IS HIGH THAT MOST PORTS WL EXPERIENCE
THUNDERSTORMS WITH COVERAGE INCREASING FM N TO S AS THE DAY
PROGRESSES. IFR RESTRICTIONS IN HEAVY RAIN CAN BE ANTICIPATED AND
SFC GUSTS IN EXCESS OF 50KT ARE POSSIBLE.
EXPECT NO MORE THAN SCATTERED THUNDERSTORMS THE REST OF TONIGHT.
POST-STORM STRATUS AND FOG MAY ALSO CAUSE A SHORT PERIOD OF IFR
RESTRICTIONS.
OUTLOOK...FRIDAY THROUGH MONDAY...
SCATTERED THUNDERSTORMS MAY PROVIDE RESTRICTIONS FRIDAY INTO
SATURDAY AS A SECONDARY FRONT PUSHES ACROSS THE TERMINALS. DRY VFR
CONDITIONS ARE EXPECTED UNDER SURFACE HIGH PRESSURE SUNDAY AND
MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ039>041-
048>050-057>059-068-069.
PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ020-021-029-
031-073-075.
WV...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ001>004-012-
021-022.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1126 AM EDT THU JUL 26 2012
.SYNOPSIS...
EXPECT HOT AND HUMID CONDITIONS THIS AFTERNOON, UNTIL A SQUALL
LINE OF SEVERE THUNDERSTORMS MOVES THROUGH WITH DAMAGING WIND,
HAIL, HEAVY RAIN, AND LOTS OF LIGHTNING. THERE WILL STILL BE
SCATTERED THUNDERSTORMS AROUND UNTIL A COLD FRONT BRINGS LOWER
HUMIDITY SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN CONCERN THIS AFTERNOON AND EVENING WILL BE THE PASSAGE OF
A SQUALL LINE OF SEVERE THUNDERSTORMS WITH DAMAGING WIND, HAIL,
HEAVY RAIN, AND LOTS OF LIGHTNING. SPC CONTINUES TO PROJECT A
MODERATE RISK OF SEVERE THUNDERSTORMS FOR THE ENTIRE UPPER OHIO
VALLEY, WITH WIDESPREAD DAMAGING THUNDERSTORMS THE MOST PROBABLE
SEVERE THUNDERSTORM HAZARD. HPC HAS JOINED IN WITH A SLIGHT RISK
OF EXCESSIVE RAINFALL. RAIN AMOUNTS OF MORE THAN 1.5 INCHES IN
LESS THAN 3 HOURS CAN CAUSE FLASH FLOODING IN URBAN AREAS AND
WHERE DRAINAGE IS POOR.
CONCUR WITH THESE FORECASTS BASED ON RECENT SREF INSTABILITY AND
VERTICAL SHEAR PROFILES.
RECENT SATELLITE DATA SHOWS THE LEADING EDGE OF THICKER CLOUDS
FROM KMFD TO KCVG. ALSO A BAND OF CUMULUS IS DEVELOPING FROM KHLG
TO KLEX. THE FORMER IS MORE LIKELY WHERE THE SQUALL LINE WILL
FORM, BUT THE LATTER HAS TO BE MONITORED ALSO. RECENT HRRR MODEL
OUTPUT, ALONG WITH 00Z WRF-NMM MODEL OUTPUT, SHOWS THE FOLLOWING
TIMING OF SQUALL LINE ONSET.
FRANKLIN PA TO ZANESVILLE OH/ KFKL-KZZV/: 2-4PM.
DUBOIS-PITTSBURGH PA-WHEELING WV/ KDUJ-KPIT-KHLG/: 3-5PM.
INDIANA-MORGANTOWN WV/ KIDI-KMGW/: 4-6PM.
OAKLAND MD/ K2G4/: 6 PM.
CONTINUE TO EXPECT SCATTERED THUNDERSTORMS IN THE WAKE OF THE
SYSTEM.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
RECENT SREF 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. SUNDAY SHOULD BE DRY.
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 WEDNESDAY/...
MEDIUM RANGE MODELS SHOW SURFACE HIGH PRESSURE AND DRY CONDITIONS
FOR MONDAY.
AN UPPER TROUGH IS PROGGED TO REMAIN OVER THE EAST COAST EARLY
NEXT WEEK. MODELS HINT AT A SURFACE LOW MOVING ALONG THE EAST
COAST TUESDAY AND WEDNESDAY. PLAN TO KEEP CHANCE POPS FOR SHOWERS
AND THUNDERSTORMS MONDAY NIGHT THROUGH WEDNESDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THE MAIN FORECAST ISSUE WL BE THE DEVELOPMENT AND COVERAGE OF TSRA AS
OUTFLOW FM A GREAT LAKES MCS...AS WELL AS THE CDFNT MOVE TOWARD
THE REGION. CONFIDENCE IS HIGH THAT MOST PORTS WL EXPERIENCE
THUNDERSTORMS WITH COVERAGE INCREASING FM N TO S AS THE DAY
PROGRESSES. IFR RESTRICTIONS IN HEAVY RAIN CAN BE ANTICIPATED AND
SFC GUSTS IN EXCESS OF 50KT ARE POSSIBLE.
EXPECT NO MORE THAN SCATTERED THUNDERSTORMS THE REST OF TONIGHT.
POST-STORM FOG MAY ALSO CAUSE A SHORT PERIOD OF IFR RESTRICTIONS.
OUTLOOK...FRIDAY THROUGH MONDAY...
SCATTERED THUNDERSTORMS MAY PROVIDE RESTRICTIONS FRIDAY INTO
SATURDAY AS A SECONDARY FRONT PUSHES ACROSS THE TERMINALS. DRY VFR
CONDITIONS ARE EXPECTED UNDER SURFACE HIGH PRESSURE SUNDAY AND
MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ039>041-
048>050-057>059-068-069.
PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ020-021-029-
031-073-075.
WV...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ001>004-012-
021-022.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
726 PM EDT FRI JUL 27 2012
.AVIATION...
//DISCUSSION...
POTENTIAL FOR ADDITIONAL HEAVIER RAINFALL AND EMBEDDED THUNDER WILL
RAPIDLY DIMINISH THROUGH THE LATTER HALF OF THE EVENING UNDER
DECREASING INSTABILITY AND OVERALL FORCING. UPPER WAVE LIFTING
THROUGH DURING THIS TIME MAY PROMOTE A FEW BRIEF HEAVIER BURSTS OF
RAIN PRIOR TO MIDNIGHT...BUT THE SHRINKING PROBABILITY WILL PRECLUDE
A SPECIFIC MENTION UNLESS RADAR TRENDS SUGGEST OTHERWISE. A
LINGERING SURFACE TROUGH RESIDING WITHIN LOW LEVEL NORTHEAST FLOW
WILL MAINTAIN SOME POCKETS OF LOWER STRATUS INTO TONIGHT...BEFORE
DRIER AIR WORKING IN FROM THE NORTH ERODES THIS DECK THROUGH THE
MORNING HOURS. HIGH PRESSURE GRADUALLY BUILDS IN ON SATURDAY
BRINGING MOSTLY CLEAR SKIES AND LIGHTER NORTHEAST WINDS
//DTW THRESHOLD THREATS...
* VERY LOW PROBABILITY FOR ADDITIONAL THUNDERSTORMS TO IMPACT THE
TERMINAL THROUGH 03Z.
&&
.PREV DISCUSSION...ISSUED 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.
&&
.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.
&&
$$
AVIATION.....MR
SHORT TERM...SC
LONG TERM....MM
MARINE.......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
150 PM EDT THU JUL 26 2012
.SYNOPSIS...
ISSUED AT 1014 AM EDT THU JUL 26 2012
AFTER LOW PRESSURE AND ITS ATTENDANT SHWRS EXIT INTO LAKE HURON BY
1 PM...TODAY WILL FEATURE A BREAK IN THE ACTION. ANOTHER SYSTEM
WILL MOVE ACROSS NORTHERN MICHIGAN FRIDAY...BRINGING ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE WILL THEN BRING
PLEASANT WEATHER FOR THE WEEKEND. THERE WILL BE MORE CHANCES FOR
SHOWERS AND THUNDERSTORMS EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 150 PM EDT THU JUL 26 2012
TEMPS ARE SLOWLY RESPONDING TO THINNING STRATUS. DID ADJUST CLOUD
COVER UP THE REST OF THE DAYLIGHT HRS TO SIGNIFICANTLY SLOW DOWN
TRANSITION TO P/CLOUDY. DON`T EXPECT SUBSTANTIAL DECREASE IN CLDS
UNTIL LOSS OF HEATING 6-10 PM. HAD TO UPDATE FCST TO INCLUDE DRZL
AS UPSLOPE FLOW INCREASED IN WAKE OF DEPARTING SFC LOW. DRZL IS
NOW ENDING BUT AS SCT SHWRS DEVELOP S/E OF GRAYLING. SHOULD SEE
MORE AND MORE SUN AS AFTN WEARS ON. CURRENTLY NOT EXPECTING
ADDITIONAL CONVECTIVE DEVELOPMENT ALONG M-55 FROM HTL-CAD-MBL...
DESPITE TSTMS DEVELOPING OVER WI. CONFIDENCE IS LOW AS WE HAVE
CONFLICTING FCSTS OF CIN WITH NAM SOUNDINGS SUGGEST MODEST CAP
HOLDS. THE 14Z RAP SOUNDINGS INDICATE MID-LVL COOLING AN ITS
REMOVAL. 0-6 KM SHEAR 35 KTS...BUT AVERAGE MLCAPE OF 700 J/KG IS
NOT SUPPORTIVE OF SVR.
UPDATE ISSUED AT 1014 AM EDT THU JUL 26 2012
SFC LOW IS OVER ARENAC COUNTY AT 14Z AND WILL HEAD INTO SAGINAW
BAY OVER THE NEXT 2 HRS. 12Z UPR-AIR ANALYSIS SHOWS POSITIVE TILT
SHRTWV TROF MOVING THRU MI ATTM. COVERAGE OF SHWRS HAS BEEN INCRSG
S/E OF GRAYLING. THIS REQUIRES SOME MINOR RECONFIG OF POPS OVER
THE NEXT 3 HRS. PASSAGE OF TROF WILL CLEAR OUT MOST OF THE MID-
HIGH MSTR/CLOUDS AND END THE SHWRS. THIS WILL ALLOW INSOLATION/BL
HEATING TO BEGIN ERODING LOW STRATUS AND LIFTING IT INTO STRATOCU.
SKIES WILL EVENTUALLY TURN P/SUNNY. SEAS ARE STILL RUNNING AROUND
3 FT AT 45002. OTHER THAN NUDGING WAVE HGTS UP TO ACCT FOR THIS...
NO OTHER CHANGES WERE NEEDED.
UPDATE ISSUED AT 632 AM EDT THU JUL 26 2012
NO MAJOR CHANGES NEEDED TO GOING FORECAST...EARLIER ISSUANCE HAD
POPS ALONG/SOUTH OF M-55 CORRIDOR THROUGH 15Z AND IF ANYTHING
COULD NUDGE THAT LINE A FEW MILES NORTH BASED ON RADAR TRENDS.
CLOUDS/AREAS OF FOG PREVALENT ACROSS REMAINDER OF THE FORECAST AREA.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 415 AM EDT THU JUL 26 2012
MIDNIGHT SURFACE ANALYSIS IS A BIT OF A MESS GIVEN THE EXTENSIVE
LINE OF CONVECTION EXTENDING FROM THE GREAT LAKES SOUTHWEST INTO THE
CENTRAL/SOUTHERN PLAINS. 999MB LOW WAS LOCATED NEAR MKE...WITH A
CONVECTIVELY ENHANCED BOUNDARY THAT RUNS FROM CENTRAL LOWER
MICHIGAN...SOUTHWEST ACROSS FEAR EASTERN IOWA/NORTHWEST MISSOURI/
EASTERN KANSAS. SEVERAL MESOHIGHS EVIDENT BEHIND THE BOUNDARY
ACROSS CENTRAL KANSAS...NORTHEAST IOWA...AND NORTHERN LOWER
MICHIGAN. SECOND COLD FRONT RUNS FROM A 1003MB SURFACE LOW OVER
NORTHWEST ONTARIO...SOUTH ACROSS MINNESOTA/NORTHWEST IOWA/EASTERN
NEBRASKA. SOME SCATTERED CONVECTION AHEAD OF THIS FRONT...WHICH IS
ASSOCIATED WITH A STRONGER SHORT WAVE OVER MANITOBA. RIGHT ENTRANCE
REGION FORCING ASSOCIATED WITH A 110KT JET STREAK OVER QUEBEC AIDING
CONVECTIVE DEVELOPMENT EARLY THIS MORNING...WITHIN A VERY MOIST AIR
MASS (1.50-2.00 INCH PRECIPITABLE WATER VALUES). MAIN CONVECTION
NOW SHIFTING SOUTH INTO CENTRAL LOWER MICHIGAN/SOUTHERN WISCONSIN
WHERE LOW LEVEL CONVERGENCE MAXIMIZED ALONG LOW LEVEL JET/CONFLUENCE
AXIS...WHILE KAPX VAD WIND PROFILE SHOWING DEEP LAYER WEST/NORTHWEST
FLOW ACROSS NORTHERN LOWER.
UPPER GREAT LAKES SURFACE LOW WILL PULL EAST RATHER QUICKLY THIS
MORNING...ALREADY GETTING STRONG PRESSURE FALLS (2-3MB/3H) OVER
SOUTHWEST ONTARIO AND SURFACE PRESSURE PATTERN IS ADJUSTING TO THAT
(LOW OVER SOUTHEAST WISCONSIN FILLING BENEATH 1-2MB/3H PRESSURE
RISES). EXPECT SURFACE LOW TO BE IN THE VICINITY OF LAKE ONTARIO BY
12Z. WILL BE WATCHING MANITOBA SHORT WAVE TROUGH DROPPING SOUTHEAST
TODAY ACROSS THE UPPER MIDWEST...WITH THIS FEATURE REACHING MICHIGAN
BY FRIDAY MORNING.
FOR TODAY...LOOKS LIKE THE BULK OF THE PRECIPITATION WILL BE SOUTH
OF THE M-55 CORRIDOR THIS MORNING...WILL MONITOR RADAR TRENDS AND
ADJUST HOW LONG WILL NEED TO KEEP A PRECIP MENTION IN FOR
GLADWIN/ARENAC COUNTIES THIS MORNING. LOW CLOUDS/FOG DEVELOPING TO
THE NORTH WITH PLENTY OF LOW LEVEL MOISTURE AROUND AFTER YESTERDAY`S
RAINS...AND THIS WILL CONTINUE TO DEVELOP/ADVECT SOUTHWARD THIS
MORNING. MAY EVEN GET SOME DRIZZLE OUT OF THIS FOR A TIME. LOW
CLOUD DECK MAY PERSIST INTO THIS AFTERNOON ESPECIALLY ACROSS
NORTHERN LOWER AS CLOUDS SLOWLY MIX THEIR WAY INTO AN SC DECK.
COULD END UP BEING A MOSTLY CLOUDY DAY ACROSS NORTHEAST LOWER...
WITH SOME MORE SUN LATER TODAY ACROSS EASTERN UPPER AND PARTS OF
NORTHWEST LOWER.
SHORT WAVE TROUGH MOVES INTO WESTERN UPPER AND WISCONSIN TONIGHT...
AND WILL PROBABLY KICK OFF SOME CONVECTION AHEAD OF IT ACROSS
WISCONSIN DURING THE AFTERNOON HOURS. STRONGER FORCING EXPECTED TO
SPREAD INTO NORTHERN MICHIGAN OVERNIGHT...INCREASING THE THREAT FOR
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM WEST TO EAST FROM
MIDNIGHT ONWARD (WILL KEEP LAKE HURON SHORELINE COUNTIES FROM APN
SOUTH DRY THROUGH THE NIGHT).
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 415 AM EDT THU JUL 26 2012
ANOTHER UPPER LEVEL LOW PRESSURE SYSTEM IS EXPECTED TO BRING
ADDITIONAL RAINFALL TO THE REGION FRIDAY. THE COMBINATION OF SLOWLY
RISING HEIGHTS AND HIGH PRESSURE BUILDING IN AT THE SURFACE IS THEN
EXPECTED TO BRING IN PLEASANT CONDITIONS FOR THE WEEKEND. ANOTHER
WEAKER TROUGH WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS FOR
THE EARLY AND MIDDLE PARTS OF NEXT WEEK. THE MAIN LONG TERM FORECAST
CONCERNS REVOLVE AROUND POPS AND HIGH TEMPERATURES FRIDAY.
FRIDAY...THE UPPER LEVEL LOW NOW EVIDENT ON WATER VAPOR IMAGERY
ACROSS SOUTHERN MANITOBA SINKS SLOWLY SOUTHEASTWARD OVER THE NEXT 36
HOURS AND TRACKS ACROSS NORTHERN MICHIGAN DURING THE DAY ON FRIDAY.
AN AREA OF DIV-Q FORCING TRAVERSES THE FORECAST AREA WHILE MODEL
SOUNDINGS/CROSS SECTIONS SHOW ABUNDANT LOW/MID LEVEL MOISTURE. THIS
IS EXPECTED TO RESULT IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS.
THEREFORE HAVE INCREASED POPS TO BETWEEN HIGH LIKELY (NORTH) TO
CATEGORICAL (INLAND SOUTH). AM NOT EXPECTING ANY STORMS TO BECOME
SEVERE DUE TO THE COMBINATION OF LIMITED SURFACE HEATING AND LIGHT
WIND FIELDS ALOFT (MEAN 0-6KM BULK SHEAR ONLY ABOUT 20 KNOTS OR SO).
IN ADDITION...WITH DEEP CLOUD COVER ANTICIPATED...WILL CONTINUE WITH
MAX TEMPERATURES ONLY IN THE LOWER TO MIDDLE 70S.
SATURDAY AND SUNDAY...EXTENDED MODELS CONTINUE TO BE IN GOOD
AGREEMENT THAT THERE WILL BE BUILDING UPPER LEVEL HEIGHTS AS A RIDGE
OF HIGH PRESSURE MOVES IN FROM THE SOUTHWEST. THIS SHOULD LEAD TO A
NICE LITTLE STRETCH OF SUMMER WEATHER WITH HIGHS FOR BOTH SATURDAY
AND SUNDAY REACHING INTO THE UPPER 70S TO LOWER 80S. LOWS IN THE
COMFORTABLE 50S TO LOWER 60S.
SUNDAY NIGHT THROUGH WEDNESDAY...A WEAKER TROUGH OF LOW PRESSURE
MOVES INTO THE REGION RESULTING IN MORE CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGHS GENERALLY RANGING FROM THE UPPER 70S NORTH TO
THE MIDDLE 80S SOUTHEAST. LOWS IN THE LOWER AND MIDDLE 60S EACH
NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 150 PM EDT THU JUL 26 2012
THIS AFTN: MVFR AT MBL SHOULD BE DONE. EXPECT MVFR CIGS TO REMAIN
AT TVC...WITH PLN/APN IMPROVING FROM IFR CIGS TO MVFR. THERE IS
LOW POTENTIAL FOR APN TO REMAIN IFR. AS STRATUS CONTINUES TO THIN
EXPECT -RA TO END AT APN BY 20Z. WINDS NW-N-NE WILL REMAIN 10 KTS
OR LESS.
CIG CONFIDENCE: ABOVE AVG
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
TIMING OF CHGS TO FLGT CONDS: AVG
TNGT: COMPLEX CLOUD EVOLUTION. EXPECT MUCH OF STRATUS/STRATOCU TO
DISSIPATE WITH LOSS OF HEATING 23-02Z. HOWEVER...CAN ENVISION ANY
MODEST IMPROVEMENT AT PLN/APN RAPIDLY DETERIORATING AS CLEARING IN
THE PRESENCE OF REMAINING HIGH MSTR WILL RESULT IN REDEVELOPMENT
OF LOW CIGS AND POSSIBLY BR/FOG. CLEARING AT MBL/TVC SHOULD ALSO
RESULT IN BR/FOG. HAVE INDICATED IFR VSBYS AFTER 06Z AT PLN/APN
WITH MVFR VSBYS TVC/MBL. WORST CASE SCENARIO: LIFR/VLIFR AT ALL
TERMINALS...BUT WITH HIGHEST PROB AT PLN/TVC. WIND BECOMES CALM.
CONFIDENCE BELOW AVG ALL ELEMENTS EXCEPT WIND.
SCT SHWRS MOVE IN WITH MVFR VSBYS POSSIBLE.
FRI THRU 18Z: WDSPRD MVFR-IFR CIGS/VSBYS LIKELY TO START. CURRENT
EXPECTATION IS SLOW IMPROVEMENT TO MVFR CIGS. SCT SHWRS CONTINUE.
ISOLD THUNDER IS POSSIBLE. CONFIDENCE AVG.
&&
.MARINE...
ISSUED AT 415 AM EDT THU JUL 26 2012
LOW PRESSURE OVER THE UPPER GREAT LAKES EARLY THIS MORNING WILL
SLIDE INTO THE LOWER GREAT LAKES TODAY...LEAVING BEHIND A GENERALLY
LIGHT NORTHERLY/CYCLONIC GRADIENT ACROSS THE UPPER LAKES TODAY
THROUGH TONIGHT. NOT EXPECTING WINDS TO BE AN ISSUE TODAY...PERHAPS
SOME RESIDUAL CHOPPINESS IN THE WAVES THIS MORNING ESPECIALLY FROM
MANISTEE-GRAND TRAVERSE LIGHT ON LAKE MICHIGAN...AND THE STRAITS-
FALSE DETOUR ZONE ON NORTHERN LAKE HURON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...HALBLAUB
SYNOPSIS...AJS
SHORT TERM...JPB
LONG TERM...AJS
AVIATION...HALBLAUB
MARINE...JPB
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1218 AM CDT THU JUL 26 2012
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION BELOW.
.DISCUSSION...
THE MAIN ISSUE IN THE SHORT TERM IS OBVIOUSLY THE CHANCES FOR
SHRA/TSRA LATE THIS AFTERNOON INTO THIS EVENING AS THE SURFACE LOW
SLIDES EAST AND THE FRONTAL BOUNDARY DROPS THROUGH THE AREA. LATEST
MSAS ANALYSIS AND SURFACE OBS SHOW A WELL DEFINED WIND SHIFT
CURRENTLY BISECTING THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST...
AND SOME CONVECTION HAS TRIED TO DEVELOP NEAR THIS OVER THE PAST
SEVERAL HOURS... BUT HAS THUS FAR BEEN UNSUCCESSFUL. THE ACTUAL
FRONTAL BOUNDARY IS STILL WELL TO THE WEST OVER THE DAKOTAS... WHERE
THE DEWPOINT GRADIENT CAN BE FOUND. THIS WILL EVENTUALLY BE PUSHED
EAST THIS EVENING AS THE MAIN UPPER SHORTWAVE CURRENTLY SEEN NEAR
THE SASKATCHEWAN/MANITOBA BORDER PUSHES SOUTHEAST. AT THIS POINT...
IT/S QUESTIONABLE AS TO WHETHER THE FORCING ASSOCIATED WITH THE
ACTUAL UPPER WAVE AND COLD FRONTAL BOUNDARY WILL MANAGE TO GET ANY
CONVECTION GOING. CONTINUED CHANCE POPS THROUGH THE REMAINDER OF THE
AFTERNOON OVER THE WESTERN CWFA TO ACCOUNT FOR THAT POSSIBILITY.
OTHERWISE... TIED PCPN CHANCES TO THE INITIAL WIND SHIFT CURRENTLY
DROPPING THROUGH THE AREA... WHICH WILL BE INTERACTING WITH AN AREA
OF MLCAPE AOA 1500 J/KG. A SUBTLE SHORTWAVE FEATURE EVIDENT ON WATER
VAPOR... AND APPARENT IN THE RAP 400-300MB PV ANALYSIS... IS
CURRENTLY LIFTING NORTHEAST FROM EASTERN NEBRASKA... AND MAY HELP TO
GET ACTIVITY GOING NEAR THE WIND SHIFT DURING THE LATE AFTERNOON
OVER THE SOUTHERN AND SOUTHEAST PORTION OF THE FORECAST AREA. SO
OVERALL... KEPT CHANCE POPS OVER THE ENTIRE AREA FOR THE REMAINDER
OF THE AFTERNOON... THEN TRANSITIONED CHANCES SOUTH AND EAST THROUGH
THE EVENING.
CHANCES FOR PCPN DEPART TO THE EAST OVERNIGHT TONIGHT AS THE SURFACE
LOW AND FRONT CONTINUE TO PUSH EAST AND A WEAK SURFACE RIDGE MOVES
INTO THE AREA. THE MAIN UPPER TROUGH DROPS TOWARD THE AREA
TOMORROW... ALONG WITH A SECONDARY SURFACE WAVE AND COLD FRONTAL
BOUNDARY. WITH THE MID-UPPER COLD POOL MOVING INTO THE AREA...
TOGETHER WITH SOME LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SURFACE
LOW AND FRONTAL BOUNDARY... WE SHOULD SEE SOME SCATTERED SHRA/TSRA
DROP SOUTHEAST ACROSS MUCH OF THE AREA FROM LATE MORNING THROUGH THE
AFTERNOON HOURS. THE BEST CHANCES WILL BE OVER THE NORTHERN AND
NORTHEAST PART OF THE AREA... BUT CAN/T RULE OUT SOME SHRA/TSRA AS
FAR SOUTH AS THE MINNESOTA RIVER VALLEY DURING THE AFTERNOON HOURS
DEPENDING UPON THE DEGREE OF DESTABILIZATION WHICH OCCURS FARTHER
SOUTH AWAY FROM THE HEART OF THE MID-LEVEL COLD POOL.
ON THURSDAY NIGHT... SCATTERED SHOWERS SHOULD DIMINISH
AROUND/AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING. BY
FRIDAY... ANY RESIDUAL ACTIVITY SHOULD BE CONFINED TO WEST CENTRAL
WI COUNTIES NORTH OF INTERSTATE 94... AND THE WARRANTED COVERAGE
SHOULD ONLY BE 20 PERCENT. H85 TEMPS COOL TO AROUND +12C TO +13C
ON FRIDAY... SO HIGHS IN THE MID 70S TO LOWER 80S RANGE APPEAR
REASONABLE WITH SCT-BKN MID CLOUDS AROUND.
DRY AND NEAR NORMAL TEMPERATURES ARE EXPECTED FOR FRIDAY NIGHT AND
SATURDAY AFTER THE EXODUS OF THE TROUGH.
SATURDAY NIGHT AND SUNDAY WILL ARRIVE WITH THE NEXT OPPORTUNITY
FOR MEASURABLE PRECIPITATION... AS MULTIPLE WEAK SHORTWAVES TOP
THE PLAINS MID LEVEL RIDGE. RELATIVELY LOW CONFIDENCE ON WHETHER
FORCING ASSOCIATED WITH THE WAVES WILL BE SUFFICIENT TO OVERCOME
DRY/WARM AIR AT MID LEVELS... SO 30-40 POPS ARE AS HIGH AS WE WILL
GO FOR NOW.
FOR MONDAY THROUGH WEDNESDAY... HIGHS FROM 85-90 ARE
EXPECTED... ALONG WITH LOWS FROM THE MID 60S TO LOWER 70S. THE
PROXIMITY OF THE RIDGE AND MEAN WESTERLY/NORTHWESTERLY FLOW WILL
COMPLICATE THE PRECIPITATION FORECAST NEXT WEEK. HAVE OPTED TO GO
DRY AT THIS POINT SINCE CONFIDENCE/PROBABILITY ARE LOW AT THIS
TIME.
&&
.AVIATION.../06Z TAF ISSUANCE/
SHOWERY ACTIVITY EXPECTED TOMORROW AFTERNOON AND EARLY EVENING
ACROSS MAINLY EASTERN MN AND WESTERN WI. FAIRLY HIGH CONFIDENCE IN
SHOWERS WITH EMBEDDED SMALL THUNDERSTORMS. IT WILL BE MUCH COOLER
ALOFT TOMORROW...SO SMALL HAIL IS POSSIBLE WITH THE STRONGEST
CORES. THINK THERE WILL BE SCATTERED TO NUMEROUS SHOWERS TOMORROW
SURROUNDING KMSP...KRNH...KEAU WITH BKN CEILINGS RIGHT NEAR THE
UPPER END OF MVFR. COVERAGE WILL BE LESS THE FARTHER WEST YOU GO
IN MN. BREEZY NORTHWEST WINDS EXPECTED.
KMSP...BRIEF BOUGHTS OF MVFR POSSIBLE TOMORROW WITH SHOWERS AND
EMBEDDED THUNDERSTORMS. HIGH CONFIDENCE IN AT LEAST SHOWERS IN THE
VICINITY OF THE AIRPORT TOMORROW.
OUTLOOK FOR KMSP FRIDAY...MVFR CEILINGS POSSIBLE EARLY
FRIDAY NIGHT THROUGH SATURDAY...VFR EXPECTED
SATURDAY NIGHT THROUGH SUNDAY...BRIEF MVFR CEILINGS/VISIBILITIES
POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/CLF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1214 PM CDT Thu Jul 26 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Short Term (Today through Saturday Night)...
After 34 days without significant precipitation at the WFO, the
sounds of a steady rain and a great lightning show have been nothing
short of a welcomed miracle. Leading gust front now washing out
along the leading edge of the CWA, with elevated post-frontal
convection being maintained ahead of several well defined radar MCV
circulations. Aided by a 25-30 knot low level jet ascending over the
gust front, expect scattered convection to persist for the next
several hours with sufficient CAPE for lightning restricted
generally along and south of a MCI-IRK line.
For today, several forecast challenges related to POPs/temperatures.
Upstream mid level closed low is still over srn Manitoba, positioned
well NW of earlier model placement. This will lead to a much later
upper wave passage across the CWA today. Although muddied by
convection and nocturnal effects, it appears that the effective cold
front is still located across srn Nebraska into central Iowa,
denoted by a modest wind shift and dewpoint gradient. Pre-frontal
dewpoints have approaches seasonal highs in the lower 70s, driven
primarily by precipitation. My concern is that once nocturnal
activity dissipates and convective cloud debris erodes, strong
daytime heating could occur in a very moist and uncapped warm sector
ahead of a rather diffuse surface frontal zone. Per 06Z NAM and
recent HRRR guidance, this theory is well supported, and have
decided to drag POPs back to the northwest. Depending on how quickly
cloud cover erodes, the airmass could support surface based
thunderstorm development as early as 18Z. Increasingly northwesterly
flow aloft (although considerably stronger over the Ohio Valley)
could support some storm organization with an attendant threat for
damaging winds if activity grows upscale before exiting the CWA.
Temperatures will be highly conditional on the erosion of cloud
cover and subsequent convective development, but will opt for
lower-mid 90s as a hedge, with cooler readings certainly not out of
the question. Although on paper this seems like a huge improvement
from the past few weeks, the considerable increase in boundary layer
dewpoints will lead to a very humid conditions and heat indices
locally around 100 degrees.
With the frontal passage tonight, northwest upper flow will become
temporarily established over the area as the mean ridge position
reorganized over the southern High Plains. Seasonably strong
mid-upper flow will yield a rather impressive elevated baroclinic
zone over the region, which will translate to the surface with
daytime mixing. Have adjusted temperatures both Friday and Saturday
to account for this gradient, with hot temperatures persisting over
west central MO/ern KS and notably more tolerable conditions over NE
MO. This gradient becomes even more impressive Saturday and would
not be surprised to see highs in the upper 80s over NE MO vs. lower
100s over and south of Kansas City. Along with the brief intrusion
of cooler air into portions of the area, it is possible that
dewpoints Fri/Sat could be even lower than forecast, with some
guidance suggesting they fall into the lower 50s.
To further complicate matters, there is justifiable concern about
MCS activity on Saturday into Saturday Night. Most 00Z guidance show
a Pacific shortwave emerging from the Rockies Friday evening,
sparking a convective complex over the Black Hills region. The sharp
elevated baroclinic zone/instability axis would suggest this complex
would be well maintained along an ESE track, reaching nrn MO
Saturday afternoon. Meanwhile, the ridge will continue to
strengthen, helping return that frontal zone north as a warm front.
Thus, the question remains whether the edge of the cap is across nrn
MO or back into Iowa by the time this system arrives. Low chance
POPs probably the best way to go for now, although this will
probably end up being an all or nothing event once it draws closer.
Bookbinder
Medium Range (Sunday through Wednesday)...
Sunday - Monday: A upper level ridge of high pressure will extend
from the Southern Plains northwestward into the Eastern Rockies.
This will leave the area under northwesterly flow aloft. A series of
shortwaves are progged to round this ridge and move into the local
area on Sunday and Monday. This will make for a challenging forecast
through this period. The best chances for precipitation will be
mainly across the northern and eastern half of the CWA through
Monday although a complex of thunderstorms could develop on Sunday
and bring the chance for thunderstorms to the southern half of the
CWA as well and as such kept slight chance POPs across the southern
portion of the forecast area on Sunday. These system will also make
forecasting temperatures challenging with the northern CWA being
cooler with the potential for precipitation and excess cloud cover.
Thusly for Sunday and Monday have a gradient of temperatures ranging
from the lower 90s across north central Missouri sloping to the
upper 90s across east central Kansas and west central Missouri.
Tuesday - Wednesday: The upper level ridge will shift slowly
eastward with the local area moving under its influence by Tuesday.
This in turn will keep the local area dry through the period.
Temperatures on the other hand will warm a bit as height rises
through the period will help temperatures warm into the mid 90s to
near 100.
73
&&
.AVIATION...
Mid level cloud cover and associated showers are currently moving
south of the terminals at the moment and skies should clear in the
next hour or so. Short term guidance continues to suggest additional
convection developing later this afternoon along the cold front that
is currently located across northern Missouri. Will hold off on
mentioning this at the moment as confidence is not high enough to
support it.
Deroche
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
616 AM CDT THU JUL 26 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Short Term (Today through Saturday Night)...
After 34 days without significant precipitation at the WFO, the
sounds of a steady rain and a great lightning show have been nothing
short of a welcomed miracle. Leading gust front now washing out
along the leading edge of the CWA, with elevated post-frontal
convection being maintained ahead of several well defined radar MCV
circulations. Aided by a 25-30 knot low level jet ascending over the
gust front, expect scattered convection to persist for the next
several hours with sufficient CAPE for lightning restricted
generally along and south of a MCI-IRK line.
For today, several forecast challenges related to POPs/temperatures.
Upstream mid level closed low is still over srn Manitoba, positioned
well NW of earlier model placement. This will lead to a much later
upper wave passage across the CWA today. Although muddied by
convection and nocturnal effects, it appears that the effective cold
front is still located across srn Nebraska into central Iowa,
denoted by a modest wind shift and dewpoint gradient. Pre-frontal
dewpoints have approaches seasonal highs in the lower 70s, driven
primarily by precipitation. My concern is that once nocturnal
activity dissipates and convective cloud debris erodes, strong
daytime heating could occur in a very moist and uncapped warm sector
ahead of a rather diffuse surface frontal zone. Per 06Z NAM and
recent HRRR guidance, this theory is well supported, and have
decided to drag POPs back to the northwest. Depending on how quickly
cloud cover erodes, the airmass could support surface based
thunderstorm development as early as 18Z. Increasingly northwesterly
flow aloft (although considerably stronger over the Ohio Valley)
could support some storm organization with an attendant threat for
damaging winds if activity grows upscale before exiting the CWA.
Temperatures will be highly conditional on the erosion of cloud
cover and subsequent convective development, but will opt for
lower-mid 90s as a hedge, with cooler readings certainly not out of
the question. Although on paper this seems like a huge improvement
from the past few weeks, the considerable increase in boundary layer
dewpoints will lead to a very humid conditions and heat indices
locally around 100 degrees.
With the frontal passage tonight, northwest upper flow will become
temporarily established over the area as the mean ridge position
reorganized over the southern High Plains. Seasonably strong
mid-upper flow will yield a rather impressive elevated baroclinic
zone over the region, which will translate to the surface with
daytime mixing. Have adjusted temperatures both Friday and Saturday
to account for this gradient, with hot temperatures persisting over
west central MO/ern KS and notably more tolerable conditions over NE
MO. This gradient becomes even more impressive Saturday and would
not be surprised to see highs in the upper 80s over NE MO vs. lower
100s over and south of Kansas City. Along with the brief intrusion
of cooler air into portions of the area, it is possible that
dewpoints Fri/Sat could be even lower than forecast, with some
guidance suggesting they fall into the lower 50s.
To further complicate matters, there is justifiable concern about
MCS activity on Saturday into Saturday Night. Most 00Z guidance show
a Pacific shortwave emerging from the Rockies Friday evening,
sparking a convective complex over the Black Hills region. The sharp
elevated baroclinic zone/instability axis would suggest this complex
would be well maintained along an ESE track, reaching nrn MO
Saturday afternoon. Meanwhile, the ridge will continue to
strengthen, helping return that frontal zone north as a warm front.
Thus, the question remains whether the edge of the cap is across nrn
MO or back into Iowa by the time this system arrives. Low chance
POPs probably the best way to go for now, although this will
probably end up being an all or nothing event once it draws closer.
Bookbinder
Medium Range (Sunday through Wednesday)...
Sunday - Monday: A upper level ridge of high pressure will extend
from the Southern Plains northwestward into the Eastern Rockies.
This will leave the area under northwesterly flow aloft. A series of
shortwaves are progged to round this ridge and move into the local
area on Sunday and Monday. This will make for a challenging forecast
through this period. The best chances for precipitation will be
mainly across the northern and eastern half of the CWA through
Monday although a complex of thunderstorms could develop on Sunday
and bring the chance for thunderstorms to the southern half of the
CWA as well and as such kept slight chance POPs across the southern
portion of the forecast area on Sunday. These system will also make
forecasting temperatures challenging with the northern CWA being
cooler with the potential for precipitation and excess cloud cover.
Thusly for Sunday and Monday have a gradient of temperatures ranging
from the lower 90s across north central Missouri sloping to the
upper 90s across east central Kansas and west central Missouri.
Tuesday - Wednesday: The upper level ridge will shift slowly
eastward with the local area moving under its influence by Tuesday.
This in turn will keep the local area dry through the period.
Temperatures on the other hand will warm a bit as height rises
through the period will help temperatures warm into the mid 90s to
near 100.
73
&&
.AVIATION...
For the 12Z TAFs, a few light showers remain around the terminals
through around 13Z. Otherwise...expect VFR conditions as mainly bkn
mid level clouds are expected at the terminals this morning through
the early afternoon hours with skies clearing out this evening.
Winds will be light and variable this morning as a cold front reside
across northwest Missouri. As this cold front drops through the
terminals late this morning, winds will pick up out of the northwest
between 5-10kts before becoming light and variable again tonight.
73
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
413 AM CDT THU JUL 26 2012
.DISCUSSION...
Short Term (Today through Saturday Night)...
After 34 days without significant precipitation at the WFO, the
sounds of a steady rain and a great lightning show have been nothing
short of a welcomed miracle. Leading gust front now washing out
along the leading edge of the CWA, with elevated post-frontal
convection being maintained ahead of several well defined radar MCV
circulations. Aided by a 25-30 knot low level jet ascending over the
gust front, expect scattered convection to persist for the next
several hours with sufficient CAPE for lightning restricted
generally along and south of a MCI-IRK line.
For today, several forecast challenges related to POPs/temperatures.
Upstream mid level closed low is still over srn Manitoba, positioned
well NW of earlier model placement. This will lead to a much later
upper wave passage across the CWA today. Although muddied by
convection and nocturnal effects, it appears that the effective cold
front is still located across srn Nebraska into central Iowa,
denoted by a modest wind shift and dewpoint gradient. Pre-frontal
dewpoints have approaches seasonal highs in the lower 70s, driven
primarily by precipitation. My concern is that once nocturnal
activity dissipates and convective cloud debris erodes, strong
daytime heating could occur in a very moist and uncapped warm sector
ahead of a rather diffuse surface frontal zone. Per 06Z NAM and
recent HRRR guidance, this theory is well supported, and have
decided to drag POPs back to the northwest. Depending on how quickly
cloud cover erodes, the airmass could support surface based
thunderstorm development as early as 18Z. Increasingly northwesterly
flow aloft (although considerably stronger over the Ohio Valley)
could support some storm organization with an attendant threat for
damaging winds if activity grows upscale before exiting the CWA.
Temperatures will be highly conditional on the erosion of cloud
cover and subsequent convective development, but will opt for
lower-mid 90s as a hedge, with cooler readings certainly not out of
the question. Although on paper this seems like a huge improvement
from the past few weeks, the considerable increase in boundary layer
dewpoints will lead to a very humid conditions and heat indices
locally around 100 degrees.
With the frontal passage tonight, northwest upper flow will become
temporarily established over the area as the mean ridge position
reorganized over the southern High Plains. Seasonably strong
mid-upper flow will yield a rather impressive elevated baroclinic
zone over the region, which will translate to the surface with
daytime mixing. Have adjusted temperatures both Friday and Saturday
to account for this gradient, with hot temperatures persisting over
west central MO/ern KS and notably more tolerable conditions over NE
MO. This gradient becomes even more impressive Saturday and would
not be surprised to see highs in the upper 80s over NE MO vs. lower
100s over and south of Kansas City. Along with the brief intrusion
of cooler air into portions of the area, it is possible that
dewpoints Fri/Sat could be even lower than forecast, with some
guidance suggesting they fall into the lower 50s.
To further complicate matters, there is justifiable concern about
MCS activity on Saturday into Saturday Night. Most 00Z guidance show
a Pacific shortwave emerging from the Rockies Friday evening,
sparking a convective complex over the Black Hills region. The sharp
elevated baroclinic zone/instability axis would suggest this complex
would be well maintained along an ESE track, reaching nrn MO
Saturday afternoon. Meanwhile, the ridge will continue to
strengthen, helping return that frontal zone north as a warm front.
Thus, the question remains whether the edge of the cap is across nrn
MO or back into Iowa by the time this system arrives. Low chance
POPs probably the best way to go for now, although this will
probably end up being an all or nothing event once it draws closer.
Bookbinder
Medium Range (Sunday through Wednesday)...
Sunday - Monday: A upper level ridge of high pressure will extend
from the Southern Plains northwestward into the Eastern Rockies.
This will leave the area under northwesterly flow aloft. A series of
shortwaves are progged to round this ridge and move into the local
area on Sunday and Monday. This will make for a challenging forecast
through this period. The best chances for precipitation will be
mainly across the northern and eastern half of the CWA through
Monday although a complex of thunderstorms could develop on Sunday
and bring the chance for thunderstorms to the southern half of the
CWA as well and as such kept slight chance POPs across the southern
portion of the forecast area on Sunday. These system will also make
forecasting temperatures challenging with the northern CWA being
cooler with the potential for precipitation and excess cloud cover.
Thusly for Sunday and Monday have a gradient of temperatures ranging
from the lower 90s across north central Missouri sloping to the
upper 90s across east central Kansas and west central Missouri.
Tuesday - Wednesday: The upper level ridge will shift slowly
eastward with the local area moving under its influence by Tuesday.
This in turn will keep the local area dry through the period.
Temperatures on the other hand will warm a bit as height rises
through the period will help temperatures warm into the mid 90s to
near 100.
73
&&
.AVIATION...
For the 06Z TAFs, scattered showers and thunderstorms will affect
the terminals through the pre-dawn hours as a cold front works
southeast. Will see gusty winds initially with the storms due to the
steep low level lapse rates. Convection will end from north to south
in the morning with clearing skies for the afternoon hours.
Generally VFR conditions except with overnight thunderstorms which
could briefly send ceilings down to MVFR.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
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 ATLEAST 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.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED AT BOTH KLBF AND KVTN TERMINALS
THROUGH THE 18Z TAF PERIOD. A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS WILL EXIST OVER SOUTHWEST NEBRASKA LATE THIS
AFTERNOON AND EVENING. HOWEVER...GIVEN THE ISOLATED COVERAGE OF
ANY DEVELOPMENT WILL LEAVE ANY MENTION OF TSRA OUT OF THE CURRENT
KLBF TAF. THIS WILL BE MONITORED AND UPDATED IF CONDITIONS
WARRANT. WINDS WILL BE CALM OVERNIGHT BEFORE SWITCHING TO THE
SOUTHEAST TOMORROW MORNING. SKIES WILL BE MOSTLY CLEAR.
&&
.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...CDC/TALYOR
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
303 PM CDT THU JUL 26 2012
.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
&&
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS EXPECTED THROUGH THE PERIOD WITH HIGH PRESSURE
BUILDING INTO THE REGION. ISOLATED EVENING STORMS COULD AFFECT
KOMA AND KLNK...BUT COVERAGE WILL BE SPARSE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
1149 PM CDT WED JUL 25 2012
.UPDATE...
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
POST-FRONTAL CONVECTION CONTINUING THIS MORNING OVER SERN NEB. AT
THIS POINT...IT APPEARS PER LATEST RADAR TREND THAT TSRA ACTIVITY
IS DONE AT ALL TERMINALS. VFR CONDITIONS THEN PREVAILING THRU THE
24HR FCST PD.
DEE
&&
.PREV DISCUSSION... /ISSUED 313 PM CDT WED JUL 25 2012/
DISCUSSION...
THUNDERSTORMS TONIGHT...THEN SOMEWHAT COOLER TEMPERATURES AND
SPORADIC PRECIP CHANCES THROUGH THE WEEKEND...ARE THE PRIMARY
FORECAST CONCERNS.
COOL FRONT WAS DRIFTING SOUTHEAST THROUGH THE CWA THIS
AFTERNOON...AND HAD JUST SLIPPED PAST A COLUMBUS TO TEKAMAH LINE AS
OF 2 PM. PLUME OF MID LEVEL MOISTURE ACROSS WESTERN INTO NORTH
CENTRAL NEBRASKA NOTED ON WATER VAPOR IMAGERY WAS SHIFTING EAST OVER
THE FRONTAL BOUNDARY. SCATTERED SHOWERS AND STORMS WERE FIRING UNDER
THIS PLUME...AFFECTING MUCH OF CENTRAL NEBRASKA AND WERE TRYING TO
SNEAK INTO OUR NORTHWESTERN CWA. SURFACE-BASED CAPE VALUES WERE
TOPPING 2000 J/KG ALONG FRONTAL BOUNDARY THIS AFTERNOON...BUT
SIGNIFICANT CINH WAS ALSO NOTED. SOMEWHAT LESS UNSTABLE AIR WAS
NOTED USING MIXED-LAYER CAPE WHERE VALUES WERE BETWEEN 1000 AND 1500
J/KG. EFFECTIVE AND BULK SHEAR WERE BOTH WEAK GIVEN RELATIVELY LIGHT
MID LEVEL FLOW. SO ORGANIZED SURFACE-BASED STORMS DO NOT APPEAR
LIKELY THIS EVENING. HOWEVER STEEP MID LEVEL LAPSE RATES SHOULD
ALLOW FOR QUICK VERTICAL DEVELOPMENT OF ANY CONVECTION THAT FIRES IN
OUR CWA...THEN COLLAPSING OF THOSE STORMS COULD PRODUCE STRONG TO
SEVERE WIND GUSTS WITH TEMPERATURE/DEW POINT SPREADS APPROACHING
40F. DOWNDRAFT CAPE OF 1800 J/KG WAS ALSO MAXIMIZED ALONG FRONTAL
BOUNDARY.
GIVEN SHOWERS AND STORMS WERE ALREADY FIRING AND APPROACHING THE
CWA...COMBINED WITH ALL SHORT-RANGE MODEL OUTPUT SUGGESTING
PRECIPITATION NEAR AND BEHIND FRONTAL BOUNDARY...WILL INCREASE POPS
ACROSS MOST OF THE CWA FOR THIS EVENING. 15-16Z HRRR SEEMS TO
HAVE A DECENT HANDLE ON CURRENT PRECIPITATION...AND FIRES
CONVECTION ALONG FRONTAL BOUNDARY AS IT SINKS FARTHER SOUTHEAST
INTO THE CWA. MODELS ALSO SHOW POST-FRONTAL PRECIPITATION
CONTINUING THROUGH THE NIGHT AIDED BY RIGHT ENTRANCE REGION OF MID
LEVEL JET...THOUGH COVERAGE WILL CERTAINLY WANE AS WE GO PAST
MIDNIGHT.
SOME LINGERING SHOWERS/STORMS COULD AFFECT OUR FAR SOUTHEAST CWA
THURSDAY MORNING...BUT THAT SHOULD EXIT QUICKLY. THEN NORTHWEST
LOW LEVEL FLOW AND SLOWLY COOLING 850 TEMPERATURES POINT TO
CLOSER-TO-NORMAL TEMPERATURES THURSDAY AFTERNOON. GFS IS COOLER
THAN NAM IN THIS REGARD. WILL CONTINUE WITH HIGHS IN THE LOWER
90S...WHICH IS RIGHT IN THE MIDDLE OF NAM/GFS MOS NUMBERS. ONE
CAVEAT TO WATCH FOR IS DOWNSLOPING NORTHWEST FLOW PUSHING HIGHS A
FEW DEGREES WARMER AS PER NAM.
SURFACE HIGH WILL SETTLE ACROSS THE AREA THROUGH FRIDAY AFTERNOON
WITH RETURN FLOW BEGINNING FRIDAY NIGHT. LOWS IN THE LOW TO MID 60S
LOOK GOOD FOR FRIDAY MORNING...WITH HIGHS FRIDAY AFTERNOON RIGHT
AT NORMAL IN THE UPPER 80S.
GFS HAS ADVERTISED THE LAST FEW DAYS A MID LEVEL SHORTWAVE ROLLING
INTO THE PLAINS FRIDAY NIGHT AND SATURDAY MORNING. OTHER MODELS HAVE
COME IN LINE WITH THIS THINKING...SO CONFIDENCE IS GROWING ON PRECIP
CHANCES THEN. EXPECT WARM ADVECTION ON MODERATE LOW LEVEL JET AHEAD
OF WAVE TO FIRE CONVECTION AFTER MIDNIGHT IN NORTHEAST
NEBRASKA...WITH THIS PRECIP TURNING SOUTHEAST DOWN THE RIVER BY
MORNING. HAVE INCREASED POPS ACCORDINGLY...WITH HIGHEST CHANCES
ALONG SOUTH DAKOTA BORDER AND THROUGH AREAS NORTH AND NORTHEAST OF
OMAHA.
A SECOND SHORTWAVE LOOKS TO ROLL THROUGH AGAIN SATURDAY NIGHT AND
SUNDAY WITH SIMILAR WARM ADVECTION SIGNALS SUGGESTING CONVECTION
WILL FIRE AGAIN. ECMWF IS MORE BULLISH ON FRIDAY NIGHT WAVE...AND
PUSHES SATURDAY NIGHT PRECIP A BIT FARTHER TO THE NORTHEAST THAN
GFS.
LINGERING FRONTAL BOUNDARY BEHIND THIS SYSTEM WILL MOST LIKELY SET
UP ACROSS OUR CWA FOR MONDAY...WHICH MAY FOCUS A FEW STORMS MONDAY
AFTERNOON. SO WILL KEEP A SMALL POP GOING THEN.
UPPER RIDGE WILL BEGIN BUILDING BACK INTO THE REGION BEYOND
MONDAY...SO HAVE KEPT FORECAST DRY AND A BIT WARMER THEN. HAVE
HIGHS IN THE UPPER 80S TO LOWER 90S SATURDAY...THEN LOWER 90S
SUNDAY...BEFORE GRADUALLY INCREASING HIGHS TOWARD THE MID AND
UPPER 90S BY WEDNESDAY.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1122 PM MDT WED JUL 25 2012
.AVIATION...
06Z TAF CYCLE
UPPER HIGH CENTER TO SHIFT OVER NORTHWEST NM THURSDAY. ISOLD TO WDLY
SCT CONVECTION TO LINGER OVER EASTERN NM BEFORE 12Z EAST OF THE
PECOS VALLEY AS SURFACE BOUNDARY SAGS INTO THE REGION.
&&
.DISCUSSION...253 PM MDT WED JUL 25 2012...
...POTENTIAL FOR LOCALLY HEAVY RAIN WILL CONTINUE THRU THE WEEKEND...
AFTERNOON RADAR AND SATELLITE TRENDS ALIGNING VERY WELL WITH THE LATEST
HIRES HRRR AND RUC13 MODELS...INCREASING CONFIDENCE THAT MAIN FOCUS FOR
HEAVY RAINFALL WILL BE ALONG AND EAST OF THE CENTRAL MT CHAIN INTO THIS
EVENING. PWAT VALUES PER CIRA IMAGERY ARE BTWN 1 AND 1.2 INCHES WHICH
IS 100-125 PCT OF NORMAL. A WELL DEFINED VORT MAX NEARLY STATIONARY OVER
THE EAST CENTRAL PLAINS WILL FOCUS WITH A BACK DOOR FRONT TO PRODUCE
SCT TO NMRS STORMS THIS EVENING. DRIER STABLE AIR WILL QUICKLY DIMINISH
MOST ACTIVITY FOR CENTRAL AND WESTERN AREAS BY MIDNIGHT.
THE BACK DOOR FRONTAL BNDRY WILL SLIDE INTO THE RIO GRANDE VALLEY TMRW
AFTERNOON AIDED BY CONVECTION ALONG THE EAST SLOPES. GAP WINDS ARE
EXPECTED MOST AREAS. MAIN FOCUS OF THETA-E RIDGE AXIS WILL BE OVER MANY
AREAS OF CENTRAL NM. PWAT VALUES CONTINUE TO RISE TO BTWN 1.2 AND
1.4 WHICH WILL POSE AND ELEVATED THREAT FOR FLASH FLOODING. STEERING
FLOW WILL BE WEAKEST AND MOST CONVERGENT ALONG THE CONT DVD THEREFORE
A WATCH IS POSSIBLE HOWEVER WILL DELAY TO FOLLOWING SHIFTS. HAVE RAISED
POPS SLIGHTLY MORE TO COVER HIGHER CHANCES FOR THE CENTRAL VALLEYS.
BY FRIDAY THE FOCUS SHIFTS TO THE WESTERN HALF OF THE STATE WHERE HEAVY
RAINFALL POTENTIAL CONTINUES. PWATS ADVERTISED BTWN 1.2 AND 1.4 AGAIN
WITH LOTS OF INSTABILITY. STEERING FLOW WILL BECOME MORE SW TO NE AND
SPEED UP TO NEAR 15KTS SO WHILE HEAVY RAINFALL IS LIKELY THE POTENTIAL
FOR FLASH FLOODING MAY BE LIMITED TO TRAINING CELLS. EXPECT ACTIVITY
TO SLIDE NORTHEAST ON OUTFLOWS TOWARD THE RIO GRANDE VALLEY EACH EVENING
IN THIS VERY MOIST STEERING PATTERN. MAX TEMPS WILL REMAIN VERY CLOSE
TO SEASONAL NORMS WHILE MIN TEMPS REMAIN 5 TO 10F ABOVE NORMAL. GUYER
&&
.FIRE WEATHER...
AS ADVERTISED THE MAIN WETTING STORM FOCUS WILL SHIFT FROM THE
WESTERN HALF LIKE WAS SEEN YESTERDAY TO THE EASTERN HALF TODAY. A
BACK DOOR COLD FRONT HAS CUT INTO THE NORTHEAST PLAINS AND HAS
CREATED ABUNDANT STORM COVERAGE ACROSS THE SANGRE DE CRISTOS.
STORMS WILL TEND TO DRIFT OFF TO THE SOUTHEAST AND IMPACT THE
EASTERN PLAINS TONIGHT. WITH THE BOUNDARY AROUND...LOOK FOR
CONTINUED ABUNDANT RAINFALL ACROSS THE CENTRAL MOUNTAINS AND LARGE
PORTIONS OF THE EASTERN PLAINS ON THURSDAY. MORE ISOLATED ACTIVITY
WILL BE FOUND ACROSS THE WEST DURING THE NEXT 36 HOURS AS DRIER
AIR FILTERS IN. LOOKING AT SOME TEEN HUMIDITIES ACROSS THE FOUR
CORNERS AREA BY THURSDAY. HIGH TEMPERATURES WILL BE NEAR NORMAL
ALTHOUGH PERHAPS A FEW DEGREES BELOW NORMAL ACROSS THE NORTHEAST
ON THURSDAY.
BACK DOOR FRONT WILL INFILTRATE THE RIO GRANDE VALLEY LATER TONIGHT
BUT MAKE MORE OF A PUSH WESTWARD UNDERNEATH THE UPPER HIGH THURSDAY
NIGHT INTO FRIDAY MORNING. THIS WILL PUSH THE FOCUS OF WETTING
STORMS BACK TO THE WEST ON FRIDAY. ESPECIALLY FAVORING THE
CONTINENTAL DIVIDE REGION AS DEPICTED BY THE GFS AND TO A LESSER
EXTENT THE ECMWF AND NAM. THIS SHOULD BE THE REPLENISHMENT OF
MOISTURE THAT IS NEEDED TO FUEL HIGHER COVERAGE OF WETTING STORMS
ACROSS THE WESTERN HALF.
IT APPEARS THAT A CONSOLIDATED UPPER HIGH...BOTH BERMUDA AND
SUBTROPICAL...SHOULD BE FOUND OVER THE RED RIVER VALLEY BETWEEN TX
AND OK DURING THE WEEKEND AND EARLY NEXT WEEK. MODELS ARE SHOWING A
NICE MONSOONAL PLUME SIGNATURE OVER THE WESTERN THIRD TO HALF OF THE
FORECAST AREA DURING THIS PERIOD...ESPECIALLY DURING THE WEEKEND
TIME FRAME. PERHAPS SOME SUBSIDENCE/MID LVL DRY SLOT EFFECTS OVER THE
EASTERN PLAINS ALTHOUGH STEERING FLOW BY EARLY NEXT WEEK COULD TAKE
STORMS OFF THE CENTRAL MTNS INTO THE EASTERN PLAINS LATER IN THE DAY
PERIOD.
BOTH ECMWF AND GFS TREND THE UPPER HIGH CENTER BACK OVER THE STATE
AS NEXT WEEK PROGRESSES. THIS WOULD ESSENTIALLY STEER THE MONSOONAL
PLUME FURTHER WEST BUT COULD ALSO BRING ANOTHER BACK DOOR COLD FRONT
INTO THE EQUATION.
EITHER WAY...UNSETTLED WEATHER EXPECTED THROUGH THE NEXT SEVERAL
DAYS WITH THE INITIAL FOCUS ACROSS THE EASTERN HALF BUT
TRANSITIONING WESTERN HALF AS THE WEEK PROGRESSES INTO THE
WEEKEND. 50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
525 PM EDT THU JUL 26 2012
.SYNOPSIS...
A SOUTHWARD DROPPING FRONTAL BOUNDARY WILL BRING A FEW MORE SHOWERS
AND THUNDERSTORMS TO THE REGION OVERNIGHT. IT WILL REMAIN UNSETTLED
ON FRIDAY AND INTO THE BEGINNING OF THE WEEKEND WITH TEMPERATURES
REMAINING AROUND NORMAL. LATER IN THE WEEKEND DRIER AIR WILL PUSH
INTO THE REGION BRING A RETURN TO SOME SUNSHINE AND WARMER
TEMPERATURES.
&&
.NEAR TERM /THROUGH FRIDAY/...
THIS LATE AFTERNOON SFC LOW PRESSURE WAS LOCATED JUST NORTH OF LAKE
ONTARIO...WITH A WARM FRONT EXTENDING SOUTHEASTWARD TOWARDS EASTERN
NEW YORK...AND A FRONTAL BOUNDARY DRAPED BEHIND THE LOW BACK INTO
THE CENTRAL GREAT LAKES. ON WATER VAPOR IMAGERY A SHORT WAVE WAS
FOUND BACK ACROSS THE NORTHERN PLAINS. REGIONAL RADARS DISPLAYED A
CONVECTIVE LINE OF THUNDERSTORMS NOW PUSHING DEEPER INTO THE
SOUTHERN TIER AND ADVANCING EASTWARD. FARTHER TO THE NORTH A BAND OF
SHOWERS CONTINUES ACROSS THE NORTH COUNTRY NORTH OF THE WARM FRONT.
LATEST SPC MESOSCALE ANALYSIS/RAP DISPLAYS SB CAPES OF 1000 J/KG
OVER THE SOUTHERN TIER. THE RAP DISPLAYS A FINGER OF 1000+ CAPE
NOSING INTO THE WESTERN FINGER LAKES REGION THIS EARLY EVENING AND
THUNDERSTORMS COULD EXPAND NORTHWARD ACROSS THE WESTERN FINGER LAKES
INTO THIS HIGH INSTABILITY. WHILE THE MAIN THREAT OF DAMAGING WINDS
IS ASSOCIATED WITH THE LINE OF THUNDERSTORMS ADVANCING ACROSS THE
SOUTHERN TIER...A STILL 0-6 KM BULK SHEER OF 40 KNOTS COULD BRING A
GUSTY WINDS...PRIMARILY ACROSS THE GENESEE VALLEY.
SHOWERS ACROSS THE NORTH COUNTRY SHOULD GRADUALLY LIFT NORTHWARD AND
DIMINISH THROUGH THE EVENING HOURS. ELSEWHERE AS THE SFC LOW
ADVANCES SOUTH AND EASTWARD A FRONTAL BOUNDARY BEHIND THE LOW WILL
DROP SOUTHWARD ACROSS WNY AND PORTIONS OF CNY. WILL HAVE BRIEF
LIKELY POPS FOR SHOWERS AND EMBEDDED THUNDER ALONG THIS BOUNDARY
THIS EVENING.
AREAS OF FOG WILL BE LIKELY ACROSS THE NORTH COUNTRY THIS EVENING
WHERE TEMPERATURES ARE JUST ABOVE THE DEW POINT. ELSEWHERE AS THE
WINDS VEER TO NORTHWEST BEHIND THE SFC TROUGH EXPECT SOME LOWERING
OF CLOUDS AND VISIBILITIES LATER OVER NIGHT OVER AREAS SOUTH OF LAKE
ONTARIO. THIS MOIST UPSLOPE FLOW WILL MAINTAIN PLENTY OF CLOUDS
SOUTH OF LAKE ONTARIO OVERNIGHT AND KEEP TEMPERATURES ABOVE AVERAGE
WITH OVERNIGHT LOWS IN THE MID TO UPPER 60S.
ON FRIDAY A LIGHT NORTHERLY FLOW WITH AN UPPER LEVEL SHORT WAVE
APPROACHING FROM THE CENTRAL GREAT LAKES WILL MAINTAIN PLENTY OF
CLOUDS TO START THE DAY. SOME DRIZZLE IS POSSIBLE EARLY IN THE
MORNING...BUT THE GREATER CHC FOR MEASURABLE RAINFALL WILL COME
LATER IN THE DAY FRIDAY AS THE UPPER LEVEL SHORT WAVE NEARS THE
REGION.
ACROSS THE NORTH COUNTRY EXPECT SOME CLEARING THROUGH THE DAY. IF
THIS MATERIALIZES THE NORTH COUNTRY WILL LIKELY BE THE WARMEST
TOMORROW WITH HIGHS NEARING THE MID 80S. ELSEWHERE EXPECT JUST MID
70S TO LOWER 80S ACROSS THE CWA SOUTH OF THE NORTH COUNTRY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AN UPPER LEVEL TROF WILL APPROACH FROM THE UPPER LAKES FRIDAY
NIGHT...WITH THE AXIS FORECAST TO SLOWLY CROSS WESTERN NEW YORK ON
SATURDAY. MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON THE TIMING
OF THIS FEATURE...BUT QPFS VARY QUITE A BIT...WITH SOME MODELS
(NOTABLY THE 12Z RGEM AND 00Z EUROPEAN) MUCH HEAVIER ON QPF THAN
MOST OTHER GUIDANCE. FEEL THE TROF AND DAYTIME HEATING WILL BE THE
MAIN KEY TO THE DEVELOPMENT OF SHOWERS...BUT THAT ACTIVITY WILL BE
SOMEWHERE BETWEEN THE DRIER AND WETTER MODEL SOLUTIONS. FOR
NOW...LOOKING FOR SCATTERED ACTIVITY...PERHAPS BECOMING NUMEROUS
ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER ON SATURDAY.
AFTER THIS...A BROAD HIGH PRESSURE RIDGE WILL BUILD FROM THE NATIONS
MID-SECTION AND ACROSS WESTERN NEW YORK THROUGH SUNDAY. THIS SHOULD
KEEP SATURDAY NIGHT AND SUNDAY DRY...WITH A FAIR AMOUNT OF CLEAR
SKIES TOO.
WHILE SATURDAY SHOULD NOT BE A COMPLETE WASHOUT WITH HIT OR MISS
SHOWERS...TEMPERATURES STILL SHOULD BE SEASONABLE. WITH SOME BREAKS
OF SUN HIGHS SHOULD RISE INTO THE LOWER 80S. SUNDAY LOOKS TO BE A
QUITE NICE DAY...WITH SLIGHTLY ABOVE NORMAL TEMPERATURES IN THE
LOWER TO MID 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE PERIOD WILL START OFF WITH HIGH PRESSURE ACROSS THE REGION FOR
SUNDAY NIGHT AND MONDAY...WITH CONTAINED FAIR WEATHER. AFTER THIS...A
BROAD UPPER TROF WILL SLOWLY APPROACH FROM THE UPPER LAKES...AND
GRADUALLY BUILD ACROSS THE REGION MID-WEEK. THE 12Z GFS/GGEM/00Z
EUROPEAN ALL SHOW THIS PATTERN...SLOWING AND DEEPENING THIS TROF AS
IT MOVES ACROSS NEW ENGLAND. ITS SOURCE DOES NOT APPEAR TO BE
PARTICULARLY MOIST...SO DO NOT EXPECT A SOAKING RAINFALL FROM
THIS...BUT THE SHORTWAVE SHOULD BE AMPLE TO BRING PERIODIC RAIN
SHOWERS AND THUNDERSTORMS. OUTSIDE OF DIURNAL INFLUENCES ITS HARD TO
PINPOINT THE BEST CHANCE FOR SHOWERS...THOUGH THE TROF WILL
GRADUALLY SHIFT FROM WEST TO EAST.
TEMPERATURES LOOK TO BE WARMEST ON MONDAY...WITH THE HIGH IN CONTROL
MORE SUN SHOULD ALLOW FOR TEMPERATURES TO RISE INTO THE LOWER TO MID
80S. AFTER THIS...TEMPERATURES WILL DEPEND ON CLOUD COVER WHICH
SHOULD BE VARIABLE BUT MORE CLOUDS THEN SUN. EXPECT HIGHS TO
GENERALLY BE IN THE LOWER 80S...THOUGH THESE COULD VARY A BIT.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
THE LINE OF SHOWERS AND THUNDERSTORMS THAT CROSSED THE WESTERN
SOUTHERN TIER THIS AFTERNOON HAVE PUSHED EASTWARD INTO CENTRAL NEW
YORK AT THIS TIME. ISOLATED TO SCATTERED SHOWERS WILL STILL BE
POSSIBLE THROUGH THE EVENING HOURS AS A SURFACE LOW TRACKS ACROSS
THE REGION WITH THE BROADEST COVERAGE FOCUSED EAST OF LAKE
ONTARIO...CLOSEST TO THE LOW CENTER. OTHERWISE EXPECT CONDITIONS
ACROSS THE FORECAST AREA TO DETERIORATE TO IFR LATE THIS EVENING AS
COOL AND MOIST AIR FLOWS ACROSS THE AREA FROM THE NORTH IN THE WAKE
OF THE LOW. THIS MOIST UPSLOPE FLOW SHOULD LEAD TO THE DEVELOPMENT
OF IFR CIGS WITH FOG ALSO POSSIBLE...PARTICULARLY EAST OF LAKE
ONTARIO AND ACROSS THE SOUTHERN TIER WHERE THE HEAVIEST RAIN HAS
FALLEN.
IFR CONDITIONS SHOULD IMPROVE AT LEAST TO MVFR BY MID-MORNING
FRIDAY...HOWEVER SHOWERS WILL ONCE AGAIN BE POSSIBLE FRIDAY
AFTERNOON AS AN UPPER LEVEL TROUGH CROSSES THE REGION.
OUTLOOK...
FRIDAY NIGHT AND SATURDAY...MAINLY VFR WITH CHANCES FOR SHRA.
SUNDAY AND MONDAY...VFR
TUESDAY...MVFR/VFR IN CHC OF SHOWERS.
&&
.MARINE...
HAVE DROPPED THE SCA FOR LAKE ERIE AS WINDS AND WAVES HAVE DROPPED
THIS AFTERNOON. AN AREA OF LOW PRESSURE WILL CONTINUE TO ADVANCE
FROM NEAR LAKE ONTARIO INTO EASTERN NEW YORK OVERNIGHT WITH WINDS
BECOMING LIGHT WHILE VEERING TO NORTHWEST TO NORTH. SOME FOG IS
POSSIBLE OVERNIGHT...THOUGH LIKELY MORE OVER THE LAND MASS.
ON FRIDAY AND SATURDAY EXPECT WINDS AND WAVES TO REMAIN BELOW
SCA...THOUGH UNSETTLED WEATHER WILL CONTINUE.
&&
.CLIMATE...
THE 0.31 INCHES OF RAIN THAT FELL AT THE BUFFALO AIRPORT AFTER
MIDNIGHT...AND BEFORE 7 AM LST THIS MORNING MARKS THE FIRST TIME IN
43 DAYS THAT A TENTH OF AN INCH OF RAINFALL HAS FALLEN AT THE
BUFFALO AIRPORT. THE LAST TENTH OF AN INCH OR GREATER RAINFALL AT
BUFFALO WAS ON JUNE 12TH (0.25"). THIS IS THE SECOND LONGEST
STRETCH OF DAYS ON RECORD IN BUFFALO WITHOUT A TENTH OF AN INCH OF
PRECIPITATION...ONLY EXCEEDED BY A 47 DAY STRETCH BACK IN THE LATE
SUMMER OF 1876.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...THOMAS
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...WOOD
MARINE...APFFEL/THOMAS
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
347 PM EDT THU JUL 26 2012
.SYNOPSIS...
A SOUTHWARD DROPPING FRONTAL BOUNDARY WILL BRING A FEW MORE SHOWERS
AND THUNDERSTORMS TO THE REGION OVERNIGHT. IT WILL REMAIN UNSETTLED
ON FRIDAY AND INTO THE BEGINNING OF THE WEEKEND WITH TEMPERATURES
REMAINING AROUND NORMAL. LATER IN THE WEEKEND DRIER AIR WILL PUSH
INTO THE REGION BRING A RETURN TO SOME SUNSHINE AND WARMER
TEMPERATURES.
&&
.NEAR TERM /THROUGH FRIDAY/...
THIS LATE AFTERNOON SFC LOW PRESSURE WAS LOCATED JUST NORTH OF LAKE
ONTARIO...WITH A WARM FRONT EXTENDING SOUTHEASTWARD TOWARDS EASTERN
NEW YORK...AND A FRONTAL BOUNDARY DRAPED BEHIND THE LOW BACK INTO
THE CENTRAL GREAT LAKES. ON WATER VAPOR IMAGERY A SHORT WAVE WAS
FOUND BACK ACROSS THE NORTHERN PLAINS. REGIONAL RADARS DISPLAYED A
CONVECTIVE LINE OF THUNDERSTORMS NOW PUSHING DEEPER INTO THE
SOUTHERN TIER AND ADVANCING EASTWARD. FARTHER TO THE NORTH A BAND OF
SHOWERS CONTINUES ACROSS THE NORTH COUNTRY NORTH OF THE WARM FRONT.
LATEST SPC MESOSCALE ANALYSIS/RAP DISPLAYS SB CAPES OF 1000 J/KG
OVER THE SOUTHERN TIER. THE RAP DISPLAYS A FINGER OF 1000+ CAPE
NOSING INTO THE WESTERN FINGER LAKES REGION THIS EARLY EVENING AND
THUNDERSTORMS COULD EXPAND NORTHWARD ACROSS THE WESTERN FINGER LAKES
INTO THIS HIGH INSTABILITY. WHILE THE MAIN THREAT OF DAMAGING WINDS
IS ASSOCIATED WITH THE LINE OF THUNDERSTORMS ADVANCING ACROSS THE
SOUTHERN TIER...A STILL 0-6 KM BULK SHEER OF 40 KNOTS COULD BRING A
GUSTY WINDS...PRIMARILY ACROSS THE GENESEE VALLEY.
SHOWERS ACROSS THE NORTH COUNTRY SHOULD GRADUALLY LIFT NORTHWARD AND
DIMINISH THROUGH THE EVENING HOURS. ELSEWHERE AS THE SFC LOW
ADVANCES SOUTH AND EASTWARD A FRONTAL BOUNDARY BEHIND THE LOW WILL
DROP SOUTHWARD ACROSS WNY AND PORTIONS OF CNY. WILL HAVE BRIEF
LIKELY POPS FOR SHOWERS AND EMBEDDED THUNDER ALONG THIS BOUNDARY
THIS EVENING.
AREAS OF FOG WILL BE LIKELY ACROSS THE NORTH COUNTRY THIS EVENING
WHERE TEMPERATURES ARE JUST ABOVE THE DEW POINT. ELSEWHERE AS THE
WINDS VEER TO NORTHWEST BEHIND THE SFC TROUGH EXPECT SOME LOWERING
OF CLOUDS AND VISIBILITIES LATER OVER NIGHT OVER AREAS SOUTH OF LAKE
ONTARIO. THIS MOIST UPSLOPE FLOW WILL MAINTAIN PLENTY OF CLOUDS
SOUTH OF LAKE ONTARIO OVERNIGHT AND KEEP TEMPERATURES ABOVE AVERAGE
WITH OVERNIGHT LOWS IN THE MID TO UPPER 60S.
ON FRIDAY A LIGHT NORTHERLY FLOW WITH AN UPPER LEVEL SHORT WAVE
APPROACHING FROM THE CENTRAL GREAT LAKES WILL MAINTAIN PLENTY OF
CLOUDS TO START THE DAY. SOME DRIZZLE IS POSSIBLE EARLY IN THE
MORNING...BUT THE GREATER CHC FOR MEASURABLE RAINFALL WILL COME
LATER IN THE DAY FRIDAY AS THE UPPER LEVEL SHORT WAVE NEARS THE
REGION.
ACROSS THE NORTH COUNTRY EXPECT SOME CLEARING THROUGH THE DAY. IF
THIS MATERIALIZES THE NORTH COUNTRY WILL LIKELY BE THE WARMEST
TOMORROW WITH HIGHS NEARING THE MID 80S. ELSEWHERE EXPECT JUST MID
70S TO LOWER 80S ACROSS THE CWA SOUTH OF THE NORTH COUNTRY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AN UPPER LEVEL TROF WILL APPROACH FROM THE UPPER LAKES FRIDAY
NIGHT...WITH THE AXIS FORECAST TO SLOWLY CROSS WESTERN NEW YORK ON
SATURDAY. MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON THE TIMING
OF THIS FEATURE...BUT QPFS VARY QUITE A BIT...WITH SOME MODELS
(NOTABLY THE 12Z RGEM AND 00Z EUROPEAN) MUCH HEAVIER ON QPF THAN
MOST OTHER GUIDANCE. FEEL THE TROF AND DAYTIME HEATING WILL BE THE
MAIN KEY TO THE DEVELOPMENT OF SHOWERS...BUT THAT ACTIVITY WILL BE
SOMEWHERE BETWEEN THE DRIER AND WETTER MODEL SOLUTIONS. FOR
NOW...LOOKING FOR SCATTERED ACTIVITY...PERHAPS BECOMING NUMEROUS
ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER ON SATURDAY.
AFTER THIS...A BROAD HIGH PRESSURE RIDGE WILL BUILD FROM THE NATIONS
MID-SECTION AND ACROSS WESTERN NEW YORK THROUGH SUNDAY. THIS SHOULD
KEEP SATURDAY NIGHT AND SUNDAY DRY...WITH A FAIR AMOUNT OF CLEAR
SKIES TOO.
WHILE SATURDAY SHOULD NOT BE A COMPLETE WASHOUT WITH HIT OR MISS
SHOWERS...TEMPERATURES STILL SHOULD BE SEASONABLE. WITH SOME BREAKS
OF SUN HIGHS SHOULD RISE INTO THE LOWER 80S. SUNDAY LOOKS TO BE A
QUITE NICE DAY...WITH SLIGHTLY ABOVE NORMAL TEMPERATURES IN THE
LOWER TO MID 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE PERIOD WILL START OFF WITH HIGH PRESSURE ACROSS THE REGION FOR
SUNDAY NIGHT AND MONDAY...WITH CONTAINED FAIR WEATHER. AFTER THIS...A
BROAD UPPER TROF WILL SLOWLY APPROACH FROM THE UPPER LAKES...AND
GRADUALLY BUILD ACROSS THE REGION MID-WEEK. THE 12Z GFS/GGEM/00Z
EUROPEAN ALL SHOW THIS PATTERN...SLOWING AND DEEPENING THIS TROF AS
IT MOVES ACROSS NEW ENGLAND. ITS SOURCE DOES NOT APPEAR TO BE
PARTICULARLY MOIST...SO DO NOT EXPECT A SOAKING RAINFALL FROM
THIS...BUT THE SHORTWAVE SHOULD BE AMPLE TO BRING PERIODIC RAIN
SHOWERS AND THUNDERSTORMS. OUTSIDE OF DIURNAL INFLUENCES ITS HARD TO
PINPOINT THE BEST CHANCE FOR SHOWERS...THOUGH THE TROF WILL
GRADUALLY SHIFT FROM WEST TO EAST.
TEMPERATURES LOOK TO BE WARMEST ON MONDAY...WITH THE HIGH IN CONTROL
MORE SUN SHOULD ALLOW FOR TEMPERATURES TO RISE INTO THE LOWER TO MID
80S. AFTER THIS...TEMPERATURES WILL DEPEND ON CLOUD COVER WHICH
SHOULD BE VARIABLE BUT MORE CLOUDS THEN SUN. EXPECT HIGHS TO
GENERALLY BE IN THE LOWER 80S...THOUGH THESE COULD VARY A BIT.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AT 20Z THE LINE OF THUNDERSTORMS HAVE PRESSED INTO CENTRAL NEW YORK
WITH THE REMAINING PORTION OF THE TAF PERIOD UNDER MINIMAL CHCS FOR
THUNDER. WILL ADD IFR VSBYS TO THE NORTH COUNTRY WHERE TEMPERATURES
NEAR THE DEW POINT WILL FAVOR FOG THROUGH THE EVENING.
TONIGHT...THE COLD FRONT THAT IS TRAILING THE LOW WILL DROP SLOWLY
TO THE SOUTH. A NORTHERLY FLOW OF MOIST AIR BEHIND THE FRONT WILL
LIKELY RESULT IN MORE WIDESPREAD MVFR OR IFR CONDITIONS. WILL LOWER
CIGS TO IFR AT ALL TAF SITES...LINGERING THE LONGEST ACROSS THE
SOUTHERN TIER...AND JUST SOUTH OF LAKE ONTARIO ON THE WEAK UPSLOPE
FLOW FROM LAKE ONTARIO.
THROUGH THE DAY FRIDAY CIGS WILL SLOWLY LIFT BACK TO MVFR/VFR A
STRAY SHOWER IS POSSIBLE LATER IN THE MORNING AND INTO THE EARLY
AFTERNOON HOURS.
OUTLOOK...
FRIDAY NIGHT AND SATURDAY...MAINLY VFR WITH CHANCES FOR SHRA.
SUNDAY AND MONDAY...VFR
TUESDAY...MVFR/VFR IN CHC OF SHOWERS.
&&
.MARINE...
HAVE DROPPED THE SCA FOR LAKE ERIE AS WINDS AND WAVES HAVE DROPPED
THIS AFTERNOON. AN AREA OF LOW PRESSURE WILL CONTINUE TO ADVANCE
FROM NEAR LAKE ONTARIO INTO EASTERN NEW YORK OVERNIGHT WITH WINDS
BECOMING LIGHT WHILE VEERING TO NORTHWEST TO NORTH. SOME FOG IS
POSSIBLE OVERNIGHT...THOUGH LIKELY MORE OVER THE LAND MASS.
ON FRIDAY AND SATURDAY EXPECT WINDS AND WAVES TO REMAIN BELOW
SCA...THOUGH UNSETTLED WEATHER WILL CONTINUE.
&&
.CLIMATE...
THE 0.31 INCHES OF RAIN THAT FELL AT THE BUFFALO AIRPORT AFTER
MIDNIGHT...AND BEFORE 7 AM LST THIS MORNING MARKS THE FIRST TIME IN
43 DAYS THAT A TENTH OF AN INCH OF RAINFALL HAS FALLEN AT THE
BUFFALO AIRPORT. THE LAST TENTH OF AN INCH OR GREATER RAINFALL AT
BUFFALO WAS ON JUNE 12TH (0.25"). THIS IS THE SECOND LONGEST
STRETCH OF DAYS ON RECORD IN BUFFALO WITHOUT A TENTH OF AN INCH OF
PRECIPITATION...ONLY EXCEEDED BY A 47 DAY STRETCH BACK IN THE LATE
SUMMER OF 1876.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...THOMAS
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...THOMAS
MARINE...APFFEL/THOMAS
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
144 PM EDT THU JUL 26 2012
.SYNOPSIS...
LINGERING SHOWERS WILL REMAIN ACROSS THE AREA INTO EARLY
AFTERNOON...WITH THE POTENTIAL FOR ORGANIZED SEVERE STORMS BY MID
AFTERNOON...ESPECIALLY OVER THE SOUTHERN TIER AND NORTHEAST
PENNSYLVANIA. THE FRONTAL BOUNDARY WILL DRIFT SOUTHWARD ON FRIDAY
INTO SOUTHERN PENNSYLVANIA...BUT THE THREAT OF UNSETTLED WEATHER
WILL PERSIST.
&&
.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE...ELONGATED SFC LOPRES EXTENDS FM LK HURON THRU SRN
ONTARIO...WITH WMFNT DRAPED ACRS CWA MAINLY ALONG THE I-81
CORRIDOR. EXTENSIVE CLD CVR STILL EXISTS ACRS NRN HALF OF THE CWA
UP NR THE FINGER LKS INTO THE MOHAWK VLY COURTESY OF MCS WHICH
ROLLED THRU THIS MRNG. THINNING CLDS ARE STARTING TO BREAK UP FM
NEPA INTO THE CNTRL SRN TIER AND EAST INTO THE CATSKILLS AREA.
DEVELOPMENT OF TSTMS THIS AFTN WL BE DEPENDENT ON EROSION OF CLDS.
DWPTS HV RISEN INTO THE U60 ACRS WRN PORTION OF CWA WITH LOW 70S
ACRS WRN PA AND ERN OH IN TREMENDOUS SURGE OF MOISTURE.
CONVECTIVELY INDUCED S/WVS ARE EMBEDDED IN THE FLOW AND WL
INTERACT WITH MOISTURE AND INSTABILITY TO HELP SPARK OFF STORMS IN
THE CENTRAL SRN TIER BTWN 18Z-19Z PER LATEST HRRR REFLECTIVITY
IMAGE. 12Z NAM/RUC SNDGS IN BUFKIT HV LOWERED CAPE VALUES TO
AROUND 1000 J/KG...LIKELY DUE TO THE FACT THAT HEATING HAS BEEN
TEMPERED BY CLD CVR THUS FAR. LATEST SPC DAY1 OUTLOOK HAS SHIFTED
MODERATE RISK SOUTH AND ONLY INCLUDES SNIPPETS OF BROOME CNTY AND
DELAWARE CNTY ALONG WITH ALL OF SULLIVAN CNTY. SOME QUESTIONS
STILL RMN AS TO HOW THUNDERSTORMS WL DVLP IN WAKE OF CLD CVR
FURTHER TO THE NORTH. OVERALL...MAIN SVR WX THREAT FOR DAMAGING
WINDS, LARGE HAIL, AND ISOLD TORNADOES HAS SHIFTED MORE INTO THE
SRN TIER AND NEPA. CONVECTIVE MODE LOOKS TO BE IN THE FORM OF A
MORE LINEAR STRUCTURE WITH EMBEDDED BOWS. ANY DISCRETE CELL THAT
CAN DEVELOP AHD OF THE MAIN LINE WL LKLY ROTATE.
THUS HV KEPT POPS THE SAME WITH LKLY POPS PRETTY MUCH AREA WIDE BY
THIS AFTN. UPDATED SVR WX OUTLOOK, GRAPHICAL HWO AND GRIDS TO
REFLECT CURRENT THINKING.
5 AM UPDATE... AN ACTIVE DAYTIME AND EVENING PD EXPECTED.
SHRA/TSRA CONTINUE TO TRANSLATE ESEWD ACRS THE RGN ATTM...ASSOCD
WITH AN INCOMING WARM FRNT...AND ATTENDANT STG WAA FORCING AND
MOISTURE ADVECTION. STORMS ARE ELEVATED IN NATURE EARLY THIS
MRNG OVER CNY/NE PA...WITH THE BEST INSTAB STILL LOCATED WELL BACK
INTO THE WARM SECTOR...ACRS LK ERIE...LWR MI...AND THE OH VLY. DUE
TO THE ELEVATED NATURE OF THE CONVECTION ATTM...WE FEEL THE NEAR-
TERM SVR THREAT IS LOW...WITH LOCALLY +RA...SMALLER HAIL...AND
GUSTY WINDS TO ARND 40 MPH PERCEIVED TO BE THE MAIN THREATS.
HRRR/WRF SIM REFL PROGS SHOW A PSBL LULL IN THE ACTION LATER THIS
MRNG INTO THE EARLY AFTN...AS THE PRESENT ACTIVITY SLIDES FARTHER
TO THE E AND WEAKENS A BIT. IF THIS LULL DOES OCCUR...THOUGH...IT
SHOULD BE SHORT-LIVED. BY/AFTER 18Z...TSRA SHOULD REINVIGORATE...OWING
TO RAPID DESTABILIZATION AND IMPROVED UPR-LVL JET DYNAMICS. THE
EXACT EVOLUTION REMAINS UNCLEAR LATER TDY INTO THE EARLY
EVE...WITH REGARDS TO EXACTLY WHERE TSRA RE-FIRE...AND WHAT MODE
(LINEAR OR MORE DISCRETE CELLS). DEEP-LYRD SHEAR VECTORS ARE
WRLY...WHICH WOULD BE ORIENTED ORTHOGONAL TO ANY N-S BNDRYS (PRE-
FRNTL TROUGHS...OUTFLOW...OR THE ERN EDGE OF THE SFC WARM
FRNT)...AND THIS COULD FAVOR DISCRETE SUPERCELLS IN THESE
LOCATIONS. UPSTREAM ACTIVITY COMING EWD FROM LWR MI/SRN
ONT...WOULD POINT TO THE PSBLTY OF MORE CLDS/PCPN IN THE NRN HALF
OF THE FA (FINGER LKS/SRN TUG/WRN MOHAWK VLY RGNS). THIS WOULD
POTENTIALLY YIELD MORE STABLE CONDS THESE LOCALES. HOWEVER...JUST
TO THE S OVER NY`S SRN TIER AND NRN PA...THE PROSPECTS FOR MORE
SUNSHINE/BETTER HEATING ARE THERE BEHIND CURRENT ACTIVITY...ALG
WITH SOME DIFF HEATING/LEFTOVER OUTFLOW BNDRYS.
THUS...WE FEEL THE BEST SVR THREAT IS IN THE SRN HALF OF THE
CWA...GENERALLY FROM ABT 18Z...INTO THE 00-03Z TIME RANGES...AND
THIS MATCHES SPC`S OUTLOOK (MDT RISK) PRETTY WELL. INSTAB/SHEAR
COMBO (ML CAPE OF 2000-4000...0-6 KM BULK SHEAR ARND 50 KT...AND
0-1 KM HELICITY OF 100-300) ALL POINT TWDS THE LIKELIHOOD OF A
WELL DEVELOPED SQUALL LN...OR SUPERCELLS (PERHAPS EMBEDDED
TORNADIC ONES).
OBVIOUSLY...WE`LL MONITOR DEVELOPMENTS CLOSELY THROUGHOUT THE DAY
AND INTO THE EVE HRS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
UNSETTLED WX CONDITIONS EXPECTED TO CONTINUE RIGHT THROUGH EARLY
PORTIONS OF THE WEEKEND AS BROAD CYCLONIC FLOW PERSISTS OVER THE
NORTHEASTERN US. THE NEXT IN A SERIES OF UPPER SHORTWAVES WILL
DIVE SOUTHEAST TOWARDS OUR REGION BY EARLY FRI...WHICH WILL
INTERACT WITH ANOTHER SOUTHWARD MOVING COLD FRONT. AS THIS
OCCURS...EXPECT THE RENEWED DEVELOPMENT OF SHWRS/STORMS BY LATE
MORNING/AFTERNOON ACROSS PORTIONS OF THE AREA AS FRONTAL
CONVERGENCE INTERACTS WITH INCREASING FORCING FROM ALOFT. WITH
RESPECT TO SEVERE POTENTIAL...MUCH LOWER INSTABILITY WILL EXIST AS
TODAY/S MOISTURE WILL BE SCOURED OUT WITH THIS AFTERNOON/S
THUNDERSTORM ACTIVITY. THAT SAID...DESPITE MODERATELY STRONG WIND
FIELDS ALOFT (0-6 KM BULK SHEAR VECTORS ON THE ORDER OF 40
KTS)...SEVERE THREAT APPEARS MARGINAL BASED ON VERY LIMITED
INSTABILITY.
BY SATURDAY...YET ANOTHER SHORTWAVE DIVING INTO THE CENTRAL
APPALACHIANS WILL INTERACT WITH THE LINGERING FRONTAL BOUNDARY
ONCE AGAIN TO PRODUCE CONTINUED CHANCES FOR SHWRS/STORMS. UPPER
WIND FIELDS APPEAR MUCH WEAKER BY SATURDAY AS MAIN MID-LEVEL JET
CORE DIVES WELL SOUTH OF OUR REGION...THIS ORGANIZED SEVERE DOES
NOT APPEAR TO BE IN THE OFFERING. AREAL COVERAGE AS SUGGESTED BY
VARIOUS FCST MODELS TO INCLUDE THE WRF AND GFS SUPPORT MAINTAINING
CHC MENTION FOR POPS ACROSS MUCH OF THE CWA THROUGH THE DAY.
FINALLY BY SATURDAY NIGHT/EARLY SUNDAY...HIGH PRESSURE ACROSS THE
NORTH-CENTRAL GREAT LAKES WILL FINALLY BEGIN MOVING TOWARDS THE
AREA WHICH SHOULD LEAD TO A DECREASE IN SHWR/STORM ACTIVITY.
DESPITE THE PASSAGE OF A COLD FRONT ON FRIDAY...TEMPERATURES WILL
REMAIN NEAR SEASONABLE VALUES THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPDATE AS OF 1 PM...IN THE INTEREST OF TIME WITH POTENTIAL SEVERE
WX LOOMING TODAY...ONLY SUBTLE CHANGES WERE MADE TO THE LONG TERM
FORECAST TODAY WHICH WAS HEAVILY INFLUENCED BY HPC DAY 3-7
GUIDANCE.
HIGH PRESSURE PARKED OVER THE REGION DURING THE LATTER HALF OF THE
WEEKEND IS PROGGED TO GIVE WAY TO A BROAD UPPER LEVEL TROF AND
DIFFUSE SURFACE LOW PRESSURE ACROSS CNY AND NEPA BY TUESDAY. NOT MUCH
TO SINK OUR TEETH INTO AS FAR AS A BONAFIDE WEATHER MAKER...BUT
DIURNAL INSTABILITY WITHIN THE CYCLONIC FLOW WILL WARRANT CHANCES
FOR SCATTERED SHOWERS OR THUNDERSTORMS AT ANY TIME AFTER MONDAY.
IF ORGANIZED LOW PRESSURE FORMS ALONG THE EASTERN SEABOARD...THEN
A CHANCE FOR STEADIER RAIN IN SOME AREAS WILL INCREASE FOR
THURSDAY. HOWEVER, MODELS ARE NOT IN GOOD CONSENSUS WITH THAT
SOLUTION AT THIS TIME.
TEMPERATURES LOOK TO BE SEASONABLE FOR LATE JULY AND EARLY AUGUST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
130 PM UPDATE...
A COLD FRONT WILL APPROACH THE AREA WITH THUNDERSTORMS DEVELOPING
BETWEEN 18Z AND 20Z. KELM AND KITH WILL SEE -TSRA START TO AFFECT
THE TERMINALS AROUND 19Z AND REMAINING SITES WILL SEE -TSRA AFTER
20Z. SEVERE WEATHER WILL BE POSSIBLE FOR TERMINALS SOUTH OF THE
SOUTHERN TIER OF NY INTO NEPA. HAVE INCLUDED TEMPO GROUPS FOR
15G40KTS OUT OF THE WEST-NORTHWEST DIRECTION AS ANY SEVERE STORM
MOVES THROUGH THE TERMINALS.
STORMS WILL EXIT THE TERMINALS BETWEEN 01Z-03Z WITH MVFR
CONDITIONS SETTING IN BEHIND THE STORMS GIVEN MOISTURE PRESENT IN
ITS WAKE...WITH RESTRICTIONS TO VSBYS AND CIGS.
REDEVELOPMENT OF BKN CUMULUS LATE MORNING FRI WITH -SHRAS
POSSIBLE AGAIN BUT TOO EARLY TO INCLUDE MENTION IN TAFS.
OUTLOOK...
FRI NGT-SAT...RESTRICTIONS PSBL IN SHRA/TSRA.
SAT NGT - TUE...MAINLY VFR UNDER BUILDING HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ/PVN
NEAR TERM...MLJ/PVN
SHORT TERM...CMG
LONG TERM...JAB
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
141 PM EDT THU JUL 26 2012
.SYNOPSIS...
LINGERING SHOWERS WILL REMAIN ACROSS THE AREA INTO EARLY
AFTERNOON...WITH THE POTENTIAL FOR ORGANIZED SEVERE STORMS BY MID
AFTERNOON...ESPECIALLY OVER THE SOUTHERN TIER AND NORTHEAST
PENNSYLVANIA. THE FRONTAL BOUNDARY WILL DRIFT SOUTHWARD ON FRIDAY
INTO SOUTHERN PENNSYLVANIA...BUT THE THREAT OF UNSETTLED WEATHER
WILL PERSIST.
&&
.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE...ELONGATED SFC LOPRES EXTENDS FM LK HURON THRU SRN
ONTARIO...WITH WMFNT DRAPED ACRS CWA MAINLY ALONG THE I-81
CORRIDOR. EXTENSIVE CLD CVR STILL EXISTS ACRS NRN HALF OF THE CWA
UP NR THE FINGER LKS INTO THE MOHAWK VLY COURTESY OF MCS WHICH
ROLLED THRU THIS MRNG. THINNING CLDS ARE STARTING TO BREAK UP FM
NEPA INTO THE CNTRL SRN TIER AND EAST INTO THE CATSKILLS AREA.
DEVELOPMENT OF TSTMS THIS AFTN WL BE DEPENDENT ON EROSION OF CLDS.
DWPTS HV RISEN INTO THE U60 ACRS WRN PORTION OF CWA WITH LOW 70S
ACRS WRN PA AND ERN OH IN TREMENDOUS SURGE OF MOISTURE.
CONVECTIVELY INDUCED S/WVS ARE EMBEDDED IN THE FLOW AND WL
INTERACT WITH MOISTURE AND INSTABILITY TO HELP SPARK OFF STORMS IN
THE CENTRAL SRN TIER BTWN 18Z-19Z PER LATEST HRRR REFLECTIVITY
IMAGE. 12Z NAM/RUC SNDGS IN BUFKIT HV LOWERED CAPE VALUES TO
AROUND 1000 J/KG...LIKELY DUE TO THE FACT THAT HEATING HAS BEEN
TEMPERED BY CLD CVR THUS FAR. LATEST SPC DAY1 OUTLOOK HAS SHIFTED
MODERATE RISK SOUTH AND ONLY INCLUDES SNIPPETS OF BROOME CNTY AND
DELAWARE CNTY ALONG WITH ALL OF SULLIVAN CNTY. SOME QUESTIONS
STILL RMN AS TO HOW THUNDERSTORMS WL DVLP IN WAKE OF CLD CVR
FURTHER TO THE NORTH. OVERALL...MAIN SVR WX THREAT FOR DAMAGING
WINDS, LARGE HAIL, AND ISOLD TORNADOES HAS SHIFTED MORE INTO THE
SRN TIER AND NEPA. CONVECTIVE MODE LOOKS TO BE IN THE FORM OF A
MORE LINEAR STRUCTURE WITH EMBEDDED BOWS. ANY DISCRETE CELL THAT
CAN DEVELOP AHD OF THE MAIN LINE WL LKLY ROTATE.
THUS HV KEPT POPS THE SAME WITH LKLY POPS PRETTY MUCH AREA WIDE BY
THIS AFTN. UPDATED SVR WX OUTLOOK, GRAPHICAL HWO AND GRIDS TO
REFLECT CURRENT THINKING.
5 AM UPDATE... AN ACTIVE DAYTIME AND EVENING PD EXPECTED.
SHRA/TSRA CONTINUE TO TRANSLATE ESEWD ACRS THE RGN ATTM...ASSOCD
WITH AN INCOMING WARM FRNT...AND ATTENDANT STG WAA FORCING AND
MOISTURE ADVECTION. STORMS ARE ELEVATED IN NATURE EARLY THIS
MRNG OVER CNY/NE PA...WITH THE BEST INSTAB STILL LOCATED WELL BACK
INTO THE WARM SECTOR...ACRS LK ERIE...LWR MI...AND THE OH VLY. DUE
TO THE ELEVATED NATURE OF THE CONVECTION ATTM...WE FEEL THE NEAR-
TERM SVR THREAT IS LOW...WITH LOCALLY +RA...SMALLER HAIL...AND
GUSTY WINDS TO ARND 40 MPH PERCEIVED TO BE THE MAIN THREATS.
HRRR/WRF SIM REFL PROGS SHOW A PSBL LULL IN THE ACTION LATER THIS
MRNG INTO THE EARLY AFTN...AS THE PRESENT ACTIVITY SLIDES FARTHER
TO THE E AND WEAKENS A BIT. IF THIS LULL DOES OCCUR...THOUGH...IT
SHOULD BE SHORT-LIVED. BY/AFTER 18Z...TSRA SHOULD REINVIGORATE...OWING
TO RAPID DESTABILIZATION AND IMPROVED UPR-LVL JET DYNAMICS. THE
EXACT EVOLUTION REMAINS UNCLEAR LATER TDY INTO THE EARLY
EVE...WITH REGARDS TO EXACTLY WHERE TSRA RE-FIRE...AND WHAT MODE
(LINEAR OR MORE DISCRETE CELLS). DEEP-LYRD SHEAR VECTORS ARE
WRLY...WHICH WOULD BE ORIENTED ORTHOGONAL TO ANY N-S BNDRYS (PRE-
FRNTL TROUGHS...OUTFLOW...OR THE ERN EDGE OF THE SFC WARM
FRNT)...AND THIS COULD FAVOR DISCRETE SUPERCELLS IN THESE
LOCATIONS. UPSTREAM ACTIVITY COMING EWD FROM LWR MI/SRN
ONT...WOULD POINT TO THE PSBLTY OF MORE CLDS/PCPN IN THE NRN HALF
OF THE FA (FINGER LKS/SRN TUG/WRN MOHAWK VLY RGNS). THIS WOULD
POTENTIALLY YIELD MORE STABLE CONDS THESE LOCALES. HOWEVER...JUST
TO THE S OVER NY`S SRN TIER AND NRN PA...THE PROSPECTS FOR MORE
SUNSHINE/BETTER HEATING ARE THERE BEHIND CURRENT ACTIVITY...ALG
WITH SOME DIFF HEATING/LEFTOVER OUTFLOW BNDRYS.
THUS...WE FEEL THE BEST SVR THREAT IS IN THE SRN HALF OF THE
CWA...GENERALLY FROM ABT 18Z...INTO THE 00-03Z TIME RANGES...AND
THIS MATCHES SPC`S OUTLOOK (MDT RISK) PRETTY WELL. INSTAB/SHEAR
COMBO (ML CAPE OF 2000-4000...0-6 KM BULK SHEAR ARND 50 KT...AND
0-1 KM HELICITY OF 100-300) ALL POINT TWDS THE LIKELIHOOD OF A
WELL DEVELOPED SQUALL LN...OR SUPERCELLS (PERHAPS EMBEDDED
TORNADIC ONES).
OBVIOUSLY...WE`LL MONITOR DEVELOPMENTS CLOSELY THROUGHOUT THE DAY
AND INTO THE EVE HRS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
UNSETTLED WX CONDITIONS EXPECTED TO CONTINUE RIGHT THROUGH EARLY
PORTIONS OF THE WEEKEND AS BROAD CYCLONIC FLOW PERSISTS OVER THE
NORTHEASTERN US. THE NEXT IN A SERIES OF UPPER SHORTWAVES WILL
DIVE SOUTHEAST TOWARDS OUR REGION BY EARLY FRI...WHICH WILL
INTERACT WITH ANOTHER SOUTHWARD MOVING COLD FRONT. AS THIS
OCCURS...EXPECT THE RENEWED DEVELOPMENT OF SHWRS/STORMS BY LATE
MORNING/AFTERNOON ACROSS PORTIONS OF THE AREA AS FRONTAL
CONVERGENCE INTERACTS WITH INCREASING FORCING FROM ALOFT. WITH
RESPECT TO SEVERE POTENTIAL...MUCH LOWER INSTABILITY WILL EXIST AS
TODAY/S MOISTURE WILL BE SCOURED OUT WITH THIS AFTERNOON/S
THUNDERSTORM ACTIVITY. THAT SAID...DESPITE MODERATELY STRONG WIND
FIELDS ALOFT (0-6 KM BULK SHEAR VECTORS ON THE ORDER OF 40
KTS)...SEVERE THREAT APPEARS MARGINAL BASED ON VERY LIMITED
INSTABILITY.
BY SATURDAY...YET ANOTHER SHORTWAVE DIVING INTO THE CENTRAL
APPALACHIANS WILL INTERACT WITH THE LINGERING FRONTAL BOUNDARY
ONCE AGAIN TO PRODUCE CONTINUED CHANCES FOR SHWRS/STORMS. UPPER
WIND FIELDS APPEAR MUCH WEAKER BY SATURDAY AS MAIN MID-LEVEL JET
CORE DIVES WELL SOUTH OF OUR REGION...THIS ORGANIZED SEVERE DOES
NOT APPEAR TO BE IN THE OFFERING. AREAL COVERAGE AS SUGGESTED BY
VARIOUS FCST MODELS TO INCLUDE THE WRF AND GFS SUPPORT MAINTAINING
CHC MENTION FOR POPS ACROSS MUCH OF THE CWA THROUGH THE DAY.
FINALLY BY SATURDAY NIGHT/EARLY SUNDAY...HIGH PRESSURE ACROSS THE
NORTH-CENTRAL GREAT LAKES WILL FINALLY BEGIN MOVING TOWARDS THE
AREA WHICH SHOULD LEAD TO A DECREASE IN SHWR/STORM ACTIVITY.
DESPITE THE PASSAGE OF A COLD FRONT ON FRIDAY...TEMPERATURES WILL
REMAIN NEAR SEASONABLE VALUES THROUGH THE PERIOD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPDATE AS OF 1 PM...IN THE INTEREST OF TIME WITH POTENTIAL SEVERE
WX LOOMING TODAY...ONLY SUBTLE CHANGES WERE MADE TO THE LONG TERM
FORECAST TODAY WHICH WAS HEAVILY INFLUENCED BY HPC DAY 3-7
GUIDANCE.
HIGH PRESSURE PARKED OVER THE REGION DURING THE LATTER HALF OF THE
WEEKEND IS PROGGED TO GIVE WAY TO A BROAD UPPER LEVEL TROF AND
DIFFUSE SURFACE LOW PRESSURE ACROSS CNY AND NEPA BY TUESDAY. NOT MUCH
TO SINK OUR TEETH INTO AS FAR AS A BONAFIDE WEATHER MAKER...BUT
DIURNAL INSTABILITY WITHIN THE CYCLONIC FLOW WILL WARRANT CHANCES
FOR SCATTERED SHOWERS OR THUNDERSTORMS AT ANY TIME AFTER MONDAY.
IF ORGANIZED LOW PRESSURE FORMS ALONG THE EASTERN SEABOARD...THEN
A CHANCE FOR STEADIER RAIN IN SOME AREAS WILL INCREASE FOR
THURSDAY. HOWEVER, MODELS ARE NOT IN GOOD CONSENSUS WITH THAT
SOLUTION AT THIS TIME.
TEMPERATURES LOOK TO BE SEASONABLE FOR LATE JULY AND EARLY AUGUST.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
700 AM UPDATE...
A LINE OF THUNDERSTORMS HAS YET TO CLEAR KAVP. HERE...BRIEF MVFR
OR IFR VSBYS POSSIBLE THROUGH 13Z IN HEAVY RAIN. OTHERWISE SHOWERS
THROUGH 15Z MAY PRODUCE VERY BRIEF MVFR VSBYS BUT FOR THE MOST
PART AN OVC MID DECK AROUND 5KFT WITH VSBYS ABOVE 6SM EXPECTED.
AFTER SEEING A BREAK IN THE RAIN LATE THIS MORNING...A COLD FRONT
WILL APPROACH THE AREA WITH THUNDERSTORMS RE-DEVELOPING AFTER 18Z.
THESE STORMS COULD BECOME SEVERE WITH HIGH WINDS AND LARGE HAIL
POSSIBLE. BEST THREAT FOR THUNDERSTORMS WILL BE AFTER 18Z...WITH
THE HIGHEST SEVERE THREAT BETWEEN 19Z AND 23Z NORTHERN AND WESTERN
TERMINALS (KITH/KELM/KSYR/KRME)...20Z TO 24Z KBGM...AND 22Z TO 02Z
KAVP. GIVEN AN ENHANCED THREAT FOR SEVERE WEATHER...INCLUDED MVFR
VSBYS AND CIGS ALONG WITH GUSTY WINDS IN A TEMPO GROUP FOLLOWING
THE TIMING SHOWN ABOVE. BEYOND THE TEMPO PERIOD...SHOWERS AND EVEN
SOME THUNDER MAY LINGER INTO EARLY TONIGHT BUT TOO FAR OUT AND
CONFIDENCE NOT HIGH ENOUGH ON EXACT TIMING TO INCLUDE
RESTRICTIONS....THUS ONLY INCLUDED -SHRA AT THE MOMENT.
LIGHT AND VARIABLE WINDS EARLY THIS MORNING BECOME SOUTHWEST TODAY
AT AROUND 10 KTS WITH GUSTS TO 25 KTS. WINDS DIMINISH EARLY
TONIGHT AND VEER TOWARD THE WEST AND EVENTUALLY NORTHWEST.
OUTLOOK...
THUR TO FRI NGT...RESTRICTIONS PSBL IN SHRA/TSRA.
SAT/MON...MAINLY VFR UNDER BUILDING HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ/PVN
NEAR TERM...MLJ/PVN
SHORT TERM...CMG
LONG TERM...JAB
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
139 PM EDT THU JUL 26 2012
.SYNOPSIS...
LINGERING SHOWERS WILL REMAIN ACROSS THE AREA INTO EARLY
AFTERNOON...WITH THE POTENTIAL FOR ORGANIZED SEVERE STORMS BY MID
AFTERNOON...ESPECIALLY OVER THE SOUTHERN TIER AND NORTHEAST
PENNSYLVANIA. THE FRONTAL BOUNDARY WILL DRIFT SOUTHWARD ON FRIDAY
INTO SOUTHERN PENNSYLVANIA...BUT THE THREAT OF UNSETTLED WEATHER
WILL PERSIST.
&&
.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE...ELONGATED SFC LOPRES EXTENDS FM LK HURON THRU SRN
ONTARIO...WITH WMFNT DRAPED ACRS CWA MAINLY ALONG THE I-81
CORRIDOR. EXTENSIVE CLD CVR STILL EXISTS ACRS NRN HALF OF THE CWA
UP NR THE FINGER LKS INTO THE MOHAWK VLY COURTESY OF MCS WHICH
ROLLED THRU THIS MRNG. THINNING CLDS ARE STARTING TO BREAK UP FM
NEPA INTO THE CNTRL SRN TIER AND EAST INTO THE CATSKILLS AREA.
DEVELOPMENT OF TSTMS THIS AFTN WL BE DEPENDENT ON EROSION OF CLDS.
DWPTS HV RISEN INTO THE U60 ACRS WRN PORTION OF CWA WITH LOW 70S
ACRS WRN PA AND ERN OH IN TREMENDOUS SURGE OF MOISTURE.
CONVECTIVELY INDUCED S/WVS ARE EMBEDDED IN THE FLOW AND WL
INTERACT WITH MOISTURE AND INSTABILITY TO HELP SPARK OFF STORMS IN
THE CENTRAL SRN TIER BTWN 18Z-19Z PER LATEST HRRR REFLECTIVITY
IMAGE. 12Z NAM/RUC SNDGS IN BUFKIT HV LOWERED CAPE VALUES TO
AROUND 1000 J/KG...LIKELY DUE TO THE FACT THAT HEATING HAS BEEN
TEMPERED BY CLD CVR THUS FAR. LATEST SPC DAY1 OUTLOOK HAS SHIFTED
MODERATE RISK SOUTH AND ONLY INCLUDES SNIPPETS OF BROOME CNTY AND
DELAWARE CNTY ALONG WITH ALL OF SULLIVAN CNTY. SOME QUESTIONS
STILL RMN AS TO HOW THUNDERSTORMS WL DVLP IN WAKE OF CLD CVR
FURTHER TO THE NORTH. OVERALL...MAIN SVR WX THREAT FOR DAMAGING
WINDS, LARGE HAIL, AND ISOLD TORNADOES HAS SHIFTED MORE INTO THE
SRN TIER AND NEPA. CONVECTIVE MODE LOOKS TO BE IN THE FORM OF A
MORE LINEAR STRUCTURE WITH EMBEDDED BOWS. ANY DISCRETE CELL THAT
CAN DEVELOP AHD OF THE MAIN LINE WL LKLY ROTATE.
THUS HV KEPT POPS THE SAME WITH LKLY POPS PRETTY MUCH AREA WIDE BY
THIS AFTN. UPDATED SVR WX OUTLOOK, GRAPHICAL HWO AND GRIDS TO
REFLECT CURRENT THINKING.
5 AM UPDATE... AN ACTIVE DAYTIME AND EVENING PD EXPECTED.
SHRA/TSRA CONTINUE TO TRANSLATE ESEWD ACRS THE RGN ATTM...ASSOCD
WITH AN INCOMING WARM FRNT...AND ATTENDANT STG WAA FORCING AND
MOISTURE ADVECTION. STORMS ARE ELEVATED IN NATURE EARLY THIS
MRNG OVER CNY/NE PA...WITH THE BEST INSTAB STILL LOCATED WELL BACK
INTO THE WARM SECTOR...ACRS LK ERIE...LWR MI...AND THE OH VLY. DUE
TO THE ELEVATED NATURE OF THE CONVECTION ATTM...WE FEEL THE NEAR-
TERM SVR THREAT IS LOW...WITH LOCALLY +RA...SMALLER HAIL...AND
GUSTY WINDS TO ARND 40 MPH PERCEIVED TO BE THE MAIN THREATS.
HRRR/WRF SIM REFL PROGS SHOW A PSBL LULL IN THE ACTION LATER THIS
MRNG INTO THE EARLY AFTN...AS THE PRESENT ACTIVITY SLIDES FARTHER
TO THE E AND WEAKENS A BIT. IF THIS LULL DOES OCCUR...THOUGH...IT
SHOULD BE SHORT-LIVED. BY/AFTER 18Z...TSRA SHOULD REINVIGORATE...OWING
TO RAPID DESTABILIZATION AND IMPROVED UPR-LVL JET DYNAMICS. THE
EXACT EVOLUTION REMAINS UNCLEAR LATER TDY INTO THE EARLY
EVE...WITH REGARDS TO EXACTLY WHERE TSRA RE-FIRE...AND WHAT MODE
(LINEAR OR MORE DISCRETE CELLS). DEEP-LYRD SHEAR VECTORS ARE
WRLY...WHICH WOULD BE ORIENTED ORTHOGONAL TO ANY N-S BNDRYS (PRE-
FRNTL TROUGHS...OUTFLOW...OR THE ERN EDGE OF THE SFC WARM
FRNT)...AND THIS COULD FAVOR DISCRETE SUPERCELLS IN THESE
LOCATIONS. UPSTREAM ACTIVITY COMING EWD FROM LWR MI/SRN
ONT...WOULD POINT TO THE PSBLTY OF MORE CLDS/PCPN IN THE NRN HALF
OF THE FA (FINGER LKS/SRN TUG/WRN MOHAWK VLY RGNS). THIS WOULD
POTENTIALLY YIELD MORE STABLE CONDS THESE LOCALES. HOWEVER...JUST
TO THE S OVER NY`S SRN TIER AND NRN PA...THE PROSPECTS FOR MORE
SUNSHINE/BETTER HEATING ARE THERE BEHIND CURRENT ACTIVITY...ALG
WITH SOME DIFF HEATING/LEFTOVER OUTFLOW BNDRYS.
THUS...WE FEEL THE BEST SVR THREAT IS IN THE SRN HALF OF THE
CWA...GENERALLY FROM ABT 18Z...INTO THE 00-03Z TIME RANGES...AND
THIS MATCHES SPC`S OUTLOOK (MDT RISK) PRETTY WELL. INSTAB/SHEAR
COMBO (ML CAPE OF 2000-4000...0-6 KM BULK SHEAR ARND 50 KT...AND
0-1 KM HELICITY OF 100-300) ALL POINT TWDS THE LIKELIHOOD OF A
WELL DEVELOPED SQUALL LN...OR SUPERCELLS (PERHAPS EMBEDDED
TORNADIC ONES).
OBVIOUSLY...WE`LL MONITOR DEVELOPMENTS CLOSELY THROUGHOUT THE DAY
AND INTO THE EVE HRS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
530 AM UPDATE... WILL MAKE THIS SHORT...DUE TO NEAR-TERM WX
CONCERNS.
LTR TNT AND FRI...NWP CONSENSUS BRINGS A SFC COLD FRNT SWD THROUGH
THE CWA...AND DOWN TWDS THE MASON-DIXON LN. EVEN ONCE THE FRNT
PUSHES TO OUR S...UNSETTLED CONDS SHOULD PERSIST...WITH UPPER-LVL
WAVES STILL COMING ACRS FM W TO E. WE`LL USE CHC/SCTD POPS RIGHT
THROUGH SAT. THE BEST PROSPECTS FOR PCPN MAY COME FRI NGT AND
EARLY SAT...WITH THE MOST AMPLIFIED TROUGH APPROACHING IN THIS
TIME FRAME.
BY SAT NGT...AS THE BEST FORCING EXITS THE E COAST...DEEPER MOIST
AND MORE ORGANIZED PCPN SHOULD SLIDE FARTHER S AND E...WITH POPS
LWRG OVER TIME.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPDATE AS OF 1 PM...IN THE INTEREST OF TIME WITH POTENTIAL SEVERE
WX LOOMING TODAY...ONLY SUBTLE CHANGES WERE MADE TO THE LONG TERM
FORECAST TODAY WHICH WAS HEAVILY INFLUENCED BY HPC DAY 3-7
GUIDANCE.
HIGH PRESSURE PARKED OVER THE REGION DURING THE LATTER HALF OF THE
WEEKEND IS PROGGED TO GIVE WAY TO A BROAD UPPER LEVEL TROF AND
DIFFUSE SURFACE LOW PRESSURE ACROSS CNY AND NEPA BY TUESDAY. NOT MUCH
TO SINK OUR TEETH INTO AS FAR AS A BONAFIDE WEATHER MAKER...BUT
DIURNAL INSTABILITY WITHIN THE CYCLONIC FLOW WILL WARRANT CHANCES
FOR SCATTERED SHOWERS OR THUNDERSTORMS AT ANY TIME AFTER MONDAY.
IF ORGANIZED LOW PRESSURE FORMS ALONG THE EASTERN SEABOARD...THEN
A CHANCE FOR STEADIER RAIN IN SOME AREAS WILL INCREASE FOR
THURSDAY. HOWEVER, MODELS ARE NOT IN GOOD CONSENSUS WITH THAT
SOLUTION AT THIS TIME.
TEMPERATURES LOOK TO BE SEASONABLE FOR LATE JULY AND EARLY AUGUST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
130 PM UPDATE...
A COLD FRONT WILL APPROACH THE AREA WITH THUNDERSTORMS DEVELOPING
BETWEEN 18Z AND 20Z. KELM AND KITH WILL SEE -TSRA START TO AFFECT
THE TERMINALS AROUND 19Z AND REMAINING SITES WILL SEE -TSRA AFTER
20Z. SEVERE WEATHER WILL BE POSSIBLE FOR TERMINALS SOUTH OF THE
SOUTHERN TIER OF NY INTO NEPA. HAVE INCLUDED TEMPO GROUPS FOR
15G40KTS OUT OF THE WEST-NORTHWEST DIRECTION AS ANY SEVERE STORM
MOVES THROUGH THE TERMINALS.
STORMS WILL EXIT THE TERMINALS BETWEEN 01Z-03Z WITH MVFR
CONDITIONS SETTING IN BEHIND THE STORMS GIVEN MOISTURE PRESENT IN
ITS WAKE...WITH RESTRICTIONS TO VSBYS AND CIGS.
REDEVELOPMENT OF BKN CUMULUS LATE MORNING FRI WITH -SHRAS
POSSIBLE AGAIN BUT TOO EARLY TO INCLUDE MENTION IN TAFS.
OUTLOOK...
FRI NGT-SAT...RESTRICTIONS PSBL IN SHRA/TSRA.
SAT NGT - TUE...MAINLY VFR UNDER BUILDING HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ/PVN
NEAR TERM...MLJ/PVN
SHORT TERM...CMG
LONG TERM...JAB
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
100 PM EDT THU JUL 26 2012
.SYNOPSIS...
LINGERING SHOWERS WILL REMAIN ACROSS THE AREA INTO EARLY
AFTERNOON...WITH THE POTENTIAL FOR ORGANIZED SEVERE STORMS BY MID
AFTERNOON...ESPECIALLY OVER THE SOUTHERN TIER AND NORTHEAST
PENNSYLVANIA. THE FRONTAL BOUNDARY WILL DRIFT SOUTHWARD ON FRIDAY
INTO SOUTHERN PENNSYLVANIA...BUT THE THREAT OF UNSETTLED WEATHER
WILL PERSIST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11 AM UPDATE...ELONGATED SFC LOPRES EXTENDS FM LK HURON THRU SRN
ONTARIO...WITH WMFNT DRAPED ACRS CWA MAINLY ALONG THE I-81
CORRIDOR. EXTENSIVE CLD CVR STILL EXISTS ACRS NRN HALF OF THE CWA
UP NR THE FINGER LKS INTO THE MOHAWK VLY COURTESY OF MCS WHICH
ROLLED THRU THIS MRNG. THINNING CLDS ARE STARTING TO BREAK UP FM
NEPA INTO THE CNTRL SRN TIER AND EAST INTO THE CATSKILLS AREA.
DEVELOPMENT OF TSTMS THIS AFTN WL BE DEPENDENT ON EROSION OF CLDS.
DWPTS HV RISEN INTO THE U60 ACRS WRN PORTION OF CWA WITH LOW 70S
ACRS WRN PA AND ERN OH IN TREMENDOUS SURGE OF MOISTURE.
CONVECTIVELY INDUCED S/WVS ARE EMBEDDED IN THE FLOW AND WL
INTERACT WITH MOISTURE AND INSTABILITY TO HELP SPARK OFF STORMS IN
THE CENTRAL SRN TIER BTWN 18Z-19Z PER LATEST HRRR REFLECTIVITY
IMAGE. 12Z NAM/RUC SNDGS IN BUFKIT HV LOWERED CAPE VALUES TO
AROUND 1000 J/KG...LIKELY DUE TO THE FACT THAT HEATING HAS BEEN
TEMPERED BY CLD CVR THUS FAR. LATEST SPC DAY1 OUTLOOK HAS SHIFTED
MODERATE RISK SOUTH AND ONLY INCLUDES SNIPPETS OF BROOME CNTY AND
DELAWARE CNTY ALONG WITH ALL OF SULLIVAN CNTY. SOME QUESTIONS
STILL RMN AS TO HOW THUNDERSTORMS WL DVLP IN WAKE OF CLD CVR
FURTHER TO THE NORTH. OVERALL...MAIN SVR WX THREAT FOR DAMAGING
WINDS, LARGE HAIL, AND ISOLD TORNADOES HAS SHIFTED MORE INTO THE
SRN TIER AND NEPA. CONVECTIVE MODE LOOKS TO BE IN THE FORM OF A
MORE LINEAR STRUCTURE WITH EMBEDDED BOWS. ANY DISCRETE CELL THAT
CAN DEVELOP AHD OF THE MAIN LINE WL LKLY ROTATE.
THUS HV KEPT POPS THE SAME WITH LKLY POPS PRETTY MUCH AREA WIDE BY
THIS AFTN. UPDATED SVR WX OUTLOOK, GRAPHICAL HWO AND GRIDS TO
REFLECT CURRENT THINKING.
5 AM UPDATE... AN ACTIVE DAYTIME AND EVENING PD EXPECTED.
SHRA/TSRA CONTINUE TO TRANSLATE ESEWD ACRS THE RGN ATTM...ASSOCD
WITH AN INCOMING WARM FRNT...AND ATTENDANT STG WAA FORCING AND
MOISTURE ADVECTION. STORMS ARE ELEVATED IN NATURE EARLY THIS
MRNG OVER CNY/NE PA...WITH THE BEST INSTAB STILL LOCATED WELL BACK
INTO THE WARM SECTOR...ACRS LK ERIE...LWR MI...AND THE OH VLY. DUE
TO THE ELEVATED NATURE OF THE CONVECTION ATTM...WE FEEL THE NEAR-
TERM SVR THREAT IS LOW...WITH LOCALLY +RA...SMALLER HAIL...AND
GUSTY WINDS TO ARND 40 MPH PERCEIVED TO BE THE MAIN THREATS.
HRRR/WRF SIM REFL PROGS SHOW A PSBL LULL IN THE ACTION LATER THIS
MRNG INTO THE EARLY AFTN...AS THE PRESENT ACTIVITY SLIDES FARTHER
TO THE E AND WEAKENS A BIT. IF THIS LULL DOES OCCUR...THOUGH...IT
SHOULD BE SHORT-LIVED. BY/AFTER 18Z...TSRA SHOULD REINVIGORATE...OWING
TO RAPID DESTABILIZATION AND IMPROVED UPR-LVL JET DYNAMICS. THE
EXACT EVOLUTION REMAINS UNCLEAR LATER TDY INTO THE EARLY
EVE...WITH REGARDS TO EXACTLY WHERE TSRA RE-FIRE...AND WHAT MODE
(LINEAR OR MORE DISCRETE CELLS). DEEP-LYRD SHEAR VECTORS ARE
WRLY...WHICH WOULD BE ORIENTED ORTHOGONAL TO ANY N-S BNDRYS (PRE-
FRNTL TROUGHS...OUTFLOW...OR THE ERN EDGE OF THE SFC WARM
FRNT)...AND THIS COULD FAVOR DISCRETE SUPERCELLS IN THESE
LOCATIONS. UPSTREAM ACTIVITY COMING EWD FROM LWR MI/SRN
ONT...WOULD POINT TO THE PSBLTY OF MORE CLDS/PCPN IN THE NRN HALF
OF THE FA (FINGER LKS/SRN TUG/WRN MOHAWK VLY RGNS). THIS WOULD
POTENTIALLY YIELD MORE STABLE CONDS THESE LOCALES. HOWEVER...JUST
TO THE S OVER NY`S SRN TIER AND NRN PA...THE PROSPECTS FOR MORE
SUNSHINE/BETTER HEATING ARE THERE BEHIND CURRENT ACTIVITY...ALG
WITH SOME DIFF HEATING/LEFTOVER OUTFLOW BNDRYS.
THUS...WE FEEL THE BEST SVR THREAT IS IN THE SRN HALF OF THE
CWA...GENERALLY FROM ABT 18Z...INTO THE 00-03Z TIME RANGES...AND
THIS MATCHES SPC`S OUTLOOK (MDT RISK) PRETTY WELL. INSTAB/SHEAR
COMBO (ML CAPE OF 2000-4000...0-6 KM BULK SHEAR ARND 50 KT...AND
0-1 KM HELICITY OF 100-300) ALL POINT TWDS THE LIKELIHOOD OF A
WELL DEVELOPED SQUALL LN...OR SUPERCELLS (PERHAPS EMBEDDED
TORNADIC ONES).
OBVIOUSLY...WE`LL MONITOR DEVELOPMENTS CLOSELY THROUGHOUT THE DAY
AND INTO THE EVE HRS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
530 AM UPDATE... WILL MAKE THIS SHORT...DUE TO NEAR-TERM WX
CONCERNS.
LTR TNT AND FRI...NWP CONSENSUS BRINGS A SFC COLD FRNT SWD THROUGH
THE CWA...AND DOWN TWDS THE MASON-DIXON LN. EVEN ONCE THE FRNT
PUSHES TO OUR S...UNSETTLED CONDS SHOULD PERSIST...WITH UPPER-LVL
WAVES STILL COMING ACRS FM W TO E. WE`LL USE CHC/SCTD POPS RIGHT
THROUGH SAT. THE BEST PROSPECTS FOR PCPN MAY COME FRI NGT AND
EARLY SAT...WITH THE MOST AMPLIFIED TROUGH APPROACHING IN THIS
TIME FRAME.
BY SAT NGT...AS THE BEST FORCING EXITS THE E COAST...DEEPER MOIST
AND MORE ORGANIZED PCPN SHOULD SLIDE FARTHER S AND E...WITH POPS
LWRG OVER TIME.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPDATE AS OF 1 PM...IN THE INTEREST OF TIME WITH POTENTIAL SEVERE
WX LOOMING TODAY...ONLY SUBTLE CHANGES WERE MADE TO THE LONG TERM
FORECAST TODAY WHICH WAS HEAVILY INFLUENCED BY HPC DAY 3-7
GUIDANCE.
HIGH PRESSURE PARKED OVER THE REGION DURING THE LATTER HALF OF THE
WEEKEND IS PROGGED TO GIVE WAY TO A BROAD UPPER LEVEL TROF AND
DIFFUSE SURFACE LOW PRESSURE ACROSS CNY AND NEPA BY TUESDAY. NOT MUCH
TO SINK OUR TEETH INTO AS FAR AS A BONAFIDE WEATHER MAKER...BUT
DIURNAL INSTABILITY WITHIN THE CYCLONIC FLOW WILL WARRANT CHANCES
FOR SCATTERED SHOWERS OR THUNDERSTORMS AT ANY TIME AFTER MONDAY.
IF ORGANIZED LOW PRESSURE FORMS ALONG THE EASTERN SEABOARD...THEN
A CHANCE FOR STEADIER RAIN IN SOME AREAS WILL INCREASE FOR
THURSDAY. HOWEVER, MODELS ARE NOT IN GOOD CONSENSUS WITH THAT
SOLUTION AT THIS TIME.
TEMPERATURES LOOK TO BE SEASONABLE FOR LATE JULY AND EARLY AUGUST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
700 AM UPDATE...
A LINE OF THUNDERSTORMS HAS YET TO CLEAR KAVP. HERE...BRIEF MVFR
OR IFR VSBYS POSSIBLE THROUGH 13Z IN HEAVY RAIN. OTHERWISE SHOWERS
THROUGH 15Z MAY PRODUCE VERY BRIEF MVFR VSBYS BUT FOR THE MOST
PART AN OVC MID DECK AROUND 5KFT WITH VSBYS ABOVE 6SM EXPECTED.
AFTER SEEING A BREAK IN THE RAIN LATE THIS MORNING...A COLD FRONT
WILL APPROACH THE AREA WITH THUNDERSTORMS RE-DEVELOPING AFTER 18Z.
THESE STORMS COULD BECOME SEVERE WITH HIGH WINDS AND LARGE HAIL
POSSIBLE. BEST THREAT FOR THUNDERSTORMS WILL BE AFTER 18Z...WITH
THE HIGHEST SEVERE THREAT BETWEEN 19Z AND 23Z NORTHERN AND WESTERN
TERMINALS (KITH/KELM/KSYR/KRME)...20Z TO 24Z KBGM...AND 22Z TO 02Z
KAVP. GIVEN AN ENHANCED THREAT FOR SEVERE WEATHER...INCLUDED MVFR
VSBYS AND CIGS ALONG WITH GUSTY WINDS IN A TEMPO GROUP FOLLOWING
THE TIMING SHOWN ABOVE. BEYOND THE TEMPO PERIOD...SHOWERS AND EVEN
SOME THUNDER MAY LINGER INTO EARLY TONIGHT BUT TOO FAR OUT AND
CONFIDENCE NOT HIGH ENOUGH ON EXACT TIMING TO INCLUDE
RESTRICTIONS....THUS ONLY INCLUDED -SHRA AT THE MOMENT.
LIGHT AND VARIABLE WINDS EARLY THIS MORNING BECOME SOUTHWEST TODAY
AT AROUND 10 KTS WITH GUSTS TO 25 KTS. WINDS DIMINISH EARLY
TONIGHT AND VEER TOWARD THE WEST AND EVENTUALLY NORTHWEST.
OUTLOOK...
THUR TO FRI NGT...RESTRICTIONS PSBL IN SHRA/TSRA.
SAT/MON...MAINLY VFR UNDER BUILDING HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ/PVN
NEAR TERM...MLJ/PVN
SHORT TERM...MLJ
LONG TERM...JAB
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1146 AM EDT THU JUL 26 2012
.SYNOPSIS...
LINGERING SHOWERS WILL REMAIN ACROSS THE AREA INTO EARLY
AFTERNOON...WITH THE POTENTIAL FOR ORGANIZED SEVERE STORMS BY MID
AFTERNOON...ESPECIALLY OVER THE SOUTHERN TIER AND NORTHEAST
PENNSYLVANIA. THE FRONTAL BOUNDARY WILL DRIFT SOUTHWARD ON FRIDAY
INTO SOUTHERN PENNSYLVANIA...BUT THE THREAT OF UNSETTLED WEATHER
WILL PERSIST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11 AM UPDATE...ELONGATED SFC LOPRES EXTENDS FM LK HURON THRU SRN
ONTARIO...WITH WMFNT DRAPED ACRS CWA MAINLY ALONG THE I-81
CORRIDOR. EXTENSIVE CLD CVR STILL EXISTS ACRS NRN HALF OF THE CWA
UP NR THE FINGER LKS INTO THE MOHAWK VLY COURTESY OF MCS WHICH
ROLLED THRU THIS MRNG. THINNING CLDS ARE STARTING TO BREAK UP FM
NEPA INTO THE CNTRL SRN TIER AND EAST INTO THE CATSKILLS AREA.
DEVELOPMENT OF TSTMS THIS AFTN WL BE DEPENDENT ON EROSION OF CLDS.
DWPTS HV RISEN INTO THE U60 ACRS WRN PORTION OF CWA WITH LOW 70S
ACRS WRN PA AND ERN OH IN TREMENDOUS SURGE OF MOISTURE.
CONVECTIVELY INDUCED S/WVS ARE EMBEDDED IN THE FLOW AND WL
INTERACT WITH MOISTURE AND INSTABILITY TO HELP SPARK OFF STORMS IN
THE CENTRAL SRN TIER BTWN 18Z-19Z PER LATEST HRRR REFLECTIVITY
IMAGE. 12Z NAM/RUC SNDGS IN BUFKIT HV LOWERED CAPE VALUES TO
AROUND 1000 J/KG...LIKELY DUE TO THE FACT THAT HEATING HAS BEEN
TEMPERED BY CLD CVR THUS FAR. LATEST SPC DAY1 OUTLOOK HAS SHIFTED
MODERATE RISK SOUTH AND ONLY INCLUDES SNIPPETS OF BROOME CNTY AND
DELAWARE CNTY ALONG WITH ALL OF SULLIVAN CNTY. SOME QUESTIONS
STILL RMN AS TO HOW THUNDERSTORMS WL DVLP IN WAKE OF CLD CVR
FURTHER TO THE NORTH. OVERALL...MAIN SVR WX THREAT FOR DAMAGING
WINDS, LARGE HAIL, AND ISOLD TORNADOES HAS SHIFTED MORE INTO THE
SRN TIER AND NEPA. CONVECTIVE MODE LOOKS TO BE IN THE FORM OF A
MORE LINEAR STRUCTURE WITH EMBEDDED BOWS. ANY DISCRETE CELL THAT
CAN DEVELOP AHD OF THE MAIN LINE WL LKLY ROTATE.
THUS HV KEPT POPS THE SAME WITH LKLY POPS PRETTY MUCH AREA WIDE BY
THIS AFTN. UPDATED SVR WX OUTLOOK, GRAPHICAL HWO AND GRIDS TO
REFLECT CURRENT THINKING.
5 AM UPDATE... AN ACTIVE DAYTIME AND EVENING PD EXPECTED.
SHRA/TSRA CONTINUE TO TRANSLATE ESEWD ACRS THE RGN ATTM...ASSOCD
WITH AN INCOMING WARM FRNT...AND ATTENDANT STG WAA FORCING AND
MOISTURE ADVECTION. STORMS ARE ELEVATED IN NATURE EARLY THIS
MRNG OVER CNY/NE PA...WITH THE BEST INSTAB STILL LOCATED WELL BACK
INTO THE WARM SECTOR...ACRS LK ERIE...LWR MI...AND THE OH VLY. DUE
TO THE ELEVATED NATURE OF THE CONVECTION ATTM...WE FEEL THE NEAR-
TERM SVR THREAT IS LOW...WITH LOCALLY +RA...SMALLER HAIL...AND
GUSTY WINDS TO ARND 40 MPH PERCEIVED TO BE THE MAIN THREATS.
HRRR/WRF SIM REFL PROGS SHOW A PSBL LULL IN THE ACTION LATER THIS
MRNG INTO THE EARLY AFTN...AS THE PRESENT ACTIVITY SLIDES FARTHER
TO THE E AND WEAKENS A BIT. IF THIS LULL DOES OCCUR...THOUGH...IT
SHOULD BE SHORT-LIVED. BY/AFTER 18Z...TSRA SHOULD REINVIGORATE...OWING
TO RAPID DESTABILIZATION AND IMPROVED UPR-LVL JET DYNAMICS. THE
EXACT EVOLUTION REMAINS UNCLEAR LATER TDY INTO THE EARLY
EVE...WITH REGARDS TO EXACTLY WHERE TSRA RE-FIRE...AND WHAT MODE
(LINEAR OR MORE DISCRETE CELLS). DEEP-LYRD SHEAR VECTORS ARE
WRLY...WHICH WOULD BE ORIENTED ORTHOGONAL TO ANY N-S BNDRYS (PRE-
FRNTL TROUGHS...OUTFLOW...OR THE ERN EDGE OF THE SFC WARM
FRNT)...AND THIS COULD FAVOR DISCRETE SUPERCELLS IN THESE
LOCATIONS. UPSTREAM ACTIVITY COMING EWD FROM LWR MI/SRN
ONT...WOULD POINT TO THE PSBLTY OF MORE CLDS/PCPN IN THE NRN HALF
OF THE FA (FINGER LKS/SRN TUG/WRN MOHAWK VLY RGNS). THIS WOULD
POTENTIALLY YIELD MORE STABLE CONDS THESE LOCALES. HOWEVER...JUST
TO THE S OVER NY`S SRN TIER AND NRN PA...THE PROSPECTS FOR MORE
SUNSHINE/BETTER HEATING ARE THERE BEHIND CURRENT ACTIVITY...ALG
WITH SOME DIFF HEATING/LEFTOVER OUTFLOW BNDRYS.
THUS...WE FEEL THE BEST SVR THREAT IS IN THE SRN HALF OF THE
CWA...GENERALLY FROM ABT 18Z...INTO THE 00-03Z TIME RANGES...AND
THIS MATCHES SPC`S OUTLOOK (MDT RISK) PRETTY WELL. INSTAB/SHEAR
COMBO (ML CAPE OF 2000-4000...0-6 KM BULK SHEAR ARND 50 KT...AND
0-1 KM HELICITY OF 100-300) ALL POINT TWDS THE LIKELIHOOD OF A
WELL DEVELOPED SQUALL LN...OR SUPERCELLS (PERHAPS EMBEDDED
TORNADIC ONES).
OBVIOUSLY...WE`LL MONITOR DEVELOPMENTS CLOSELY THROUGHOUT THE DAY
AND INTO THE EVE HRS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
530 AM UPDATE... WILL MAKE THIS SHORT...DUE TO NEAR-TERM WX
CONCERNS.
LTR TNT AND FRI...NWP CONSENSUS BRINGS A SFC COLD FRNT SWD THROUGH
THE CWA...AND DOWN TWDS THE MASON-DIXON LN. EVEN ONCE THE FRNT
PUSHES TO OUR S...UNSETTLED CONDS SHOULD PERSIST...WITH UPPER-LVL
WAVES STILL COMING ACRS FM W TO E. WE`LL USE CHC/SCTD POPS RIGHT
THROUGH SAT. THE BEST PROSPECTS FOR PCPN MAY COME FRI NGT AND
EARLY SAT...WITH THE MOST AMPLIFIED TROUGH APPROACHING IN THIS
TIME FRAME.
BY SAT NGT...AS THE BEST FORCING EXITS THE E COAST...DEEPER MOIST
AND MORE ORGANIZED PCPN SHOULD SLIDE FARTHER S AND E...WITH POPS
LWRG OVER TIME.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS CONTINUE TO FORECAST A LONG WAVE MEAN TROF OVER THE
NORTHEASTERN CONUS DURING THE EXTENDED PERIOD. AS A RESULT, AN
UNSETTLED PATTERN IS EXPECTED TO DEVELOP ACROSS UPSTATE NY AND
NORTHEASTERN PA. THIS WILL BRING WELCOME PRECIPITATION TO MUCH OF
NY/PA.
CANNOT RULE OUT A SHOWER OR THUNDERSTORM DURING ANY 24 HOUR
PERIOD...HOWEVER IT APPEARS THE BEST CHANCE FOR PRECIPITATION WILL
COME EARLY NEXT WEEK WHEN A WEAK SURFACE CYCLONE IS FORECAST
DEVELOP UNDER THE UL TROF AXIS OVER MICHIGAN AND CENTRAL OHIO.
THIS WILL CAUSE AN INCREASED FLOW OF SFC MOISTURE INTO NY/PA, WITH
A WARM FRONT POTENTIALLY SETTING UP ACROSS OUR FORECAST AREA.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
700 AM UPDATE...
A LINE OF THUNDERSTORMS HAS YET TO CLEAR KAVP. HERE...BRIEF MVFR
OR IFR VSBYS POSSIBLE THROUGH 13Z IN HEAVY RAIN. OTHERWISE SHOWERS
THROUGH 15Z MAY PRODUCE VERY BRIEF MVFR VSBYS BUT FOR THE MOST
PART AN OVC MID DECK AROUND 5KFT WITH VSBYS ABOVE 6SM EXPECTED.
AFTER SEEING A BREAK IN THE RAIN LATE THIS MORNING...A COLD FRONT
WILL APPROACH THE AREA WITH THUNDERSTORMS RE-DEVELOPING AFTER 18Z.
THESE STORMS COULD BECOME SEVERE WITH HIGH WINDS AND LARGE HAIL
POSSIBLE. BEST THREAT FOR THUNDERSTORMS WILL BE AFTER 18Z...WITH
THE HIGHEST SEVERE THREAT BETWEEN 19Z AND 23Z NORTHERN AND WESTERN
TERMINALS (KITH/KELM/KSYR/KRME)...20Z TO 24Z KBGM...AND 22Z TO 02Z
KAVP. GIVEN AN ENHANCED THREAT FOR SEVERE WEATHER...INCLUDED MVFR
VSBYS AND CIGS ALONG WITH GUSTY WINDS IN A TEMPO GROUP FOLLOWING
THE TIMING SHOWN ABOVE. BEYOND THE TEMPO PERIOD...SHOWERS AND EVEN
SOME THUNDER MAY LINGER INTO EARLY TONIGHT BUT TOO FAR OUT AND
CONFIDENCE NOT HIGH ENOUGH ON EXACT TIMING TO INCLUDE
RESTRICTIONS....THUS ONLY INCLUDED -SHRA AT THE MOMENT.
LIGHT AND VARIABLE WINDS EARLY THIS MORNING BECOME SOUTHWEST TODAY
AT AROUND 10 KTS WITH GUSTS TO 25 KTS. WINDS DIMINISH EARLY
TONIGHT AND VEER TOWARD THE WEST AND EVENTUALLY NORTHWEST.
OUTLOOK...
THUR TO FRI NGT...RESTRICTIONS PSBL IN SHRA/TSRA.
SAT/MON...MAINLY VFR UNDER BUILDING HIPRES.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MLJ/PVN
NEAR TERM...MLJ/PVN
SHORT TERM...MLJ
LONG TERM...DJP
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
206 AM EDT THU JUL 26 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS OFFSHORE THIS EVENING AS A POTENT STORM
SYSTEM TRACKS EAST ACROSS THE GREAT LAKES...PASSING TO THE NORTH
ON THURSDAY. A WARM FRONT WILL PASS IN THE MORNING...FOLLOWED BY
A TROUGH OF LOW PRESSURE THURSDAY EVENING. A FRONTAL SYSTEM WILL
SLOWLY PUSH ACROSS AND THEN EAST OF THE REGION FRIDAY THROUGH
SATURDAY NIGHT. WEAK HIGH PRESSURE THEN BUILDS IN SUNDAY INTO THE
BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUDS FROM CONVECTION ACROSS THE GREAT LAKES HAS MOVED INTO THE
REGION. SOUTHERLY FLOW CONTINUES WITH TEMPERATURES IN THE UPPER
60S TO UPPER 70S. ADJUSTED HOURLY TEMPERATURES FOR TRENDS AND ALSO
RAISED OVERNIGHT LOWS A COUPLE OF DEGREES IN SOME OF THE OUTLYING
AREAS THAT WILL NOT FALL WITH THE CLOUD COVER.
GENERALLY DRY CONDS ON TAP FOR THE OVERNIGHT PERIOD AS HIGH PRES
OVERHEAD MOVES OFFSHORE AFTER MIDNIGHT.
STORM SYSTEM DEVELOPING OVER THE OH VALLEY...AND SHORT TERM MODELS
INDICATING EITHER THE SYSTEM OR REMNANTS OF IT WILL APPROACH
WESTERN PORTIONS OF THE FORECAST AREA TOWARDS THE END OF THE
OVERNIGHT PERIOD. LATEST HRRR MODEL HAS ONE WAVE IMPACTING THE
AREA AFTER MIDNIGHT...THEN ANOTHER WAVE APPROACHING FOR AFTER
SUNRISE THURSDAY MORNING. 18Z NAM HAS THE COMPLEX ENTERING WESTERN
PORTIONS OF THE CWA BY 12Z THURSDAY. WILL CARRY SLIGHT CHANCE POPS
FOR ORANGE COUNTY LATE...AND WILL HOLD OFF ON REST OF POPS UNTIL
THE START OF THE SECOND PERIOD.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
WITH EITHER REMNANTS OF OR THE MCS ITSELF APPROACHING THURSDAY
MORNING...WILL GO AHEAD AND INCREASE POPS TO CHANCE STARTING
BETWEEN 10-12Z OVER WESTERN ZONES...THEN WILL SPREAD THOSE POPS
EAST THROUGH 15-17Z. THIS ACTIVITY WILL BE AHEAD OF A WARM FRONT
THAT MOVES NORTH THROUGH THE REGION IN THE MORNING...THEN THE CWA
BECOMES WARM SECTORED IN THE AFTERNOON. WITH LLJ APPROACHING IN
THE MORNING...WILL GO AHEAD AND MENTION GUSTY WINDS IN THE
FORECAST FOR THURSDAY MORNING.
OTHERWISE...AN INITIAL CAP OVER THE AREA IN THE EARLY AFT SHOULD
ERODE WITH A HIGHLY UNSTABLE AIR MASS IN PLACE. MU CAPES OF 2000
TO 3000 J/KG AND 35 TO 40 KT MID LEVEL WINDS WILL SET UP A
FAVORABLE ENVIRONMENT FOR SEVERE WX DURING THE LATE AFTERNOON AND
FIRST HALF OF THE EVENING. CONVERGENCE ALONG AND AHEAD OF THE PRE-
FRONTAL TROF WILL PROVIDE THE LOW-LEVEL FORCING WITH WEAK MID
LEVEL HEIGHT FALLS. THIS FAVORS THE DEVELOPMENT OF A SCATTERED TO
NUMEROUS THUNDERSTORMS. A UNIDIRECTIONAL WIND PROFILE SUPPORTS
MULTIPLE CLUSTERS AND BOWING SEGMENTS WITH THE PRIMARY THREAT
BEING DAMAGING WINDS. SOME WEAKENING OF THE CONVECTION IS EXPECTED
AS IT MOVES OUT ACROSS EASTERN LI AND SE CT. CONVECTION SHOULD
DIMINISH BY MIDNIGHT FROM WEST TO EAST.
AN HWO HAS BEEN UPDATED TO ADDRESS THE SEVERE WEATHER POTENTIAL.
SPC HAS PLACED MOST OF THE AREA UNDER A MODERATE RISK FOR THU AFT
AND EVE. ENHANCED WORDING ADDED TO THE FORECAST TO REFLECT THE
POTENTIAL THESE STORMS WILL HAVE.
PRIOR TO THE ONSET OF THE LATE DAY CONVECTION...A SURGE OF WARM
ALOFT WITH 85H TEMP NEAR 22C WILL ALLOW DAYTIME HIGHS AWAY FROM
THE COAST TO REACH INTO THE LOWER 90S...WITH THE LOW TO MID 80S
ALONG THE COAST. HEAT INDEX VALUES FOR NYC LOOK TO BE JUST BELOW
95.
A WARM...MUGGY NIGHT WILL BE ON TAP THU NIGHT WITH LOW IN THE
LOWER TO MID 70S WITH DEW POINTS AROUND 70. FRONTAL BOUNDARY LOOKS
TO REMAIN JUST NORTH OF THE AREA.
THERE IS A MODERATE RISK OF RIP CURRENTS THURSDAY
MORNING...BECOMING HIGH THURSDAY AFTERNOON THROUGH THURSDAY
EVENING AS WINDS INCREASE TO 15 TO 25 MPH AND SURF BUILDS TO 3 TO
5 FT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
ACTIVE PERIOD TO START THE LONG TERM WITH A GRADUALLY AMPLIFYING
TROUGH WORKING FROM THE GREAT LAKES TO THE EAST COAST THROUGH
SATURDAY NIGHT. MEANWHILE AT THE SURFACE...A SLOW MOVING COLD
FRONT WITH MULTIPLE WEAK WAVES OF LOW PRESSURE WILL GRADUALLY
MOVES ACROSS AND THEN EAST OF THE REGION.
POTENTIAL FOR SCATTERED STRONG TO SEVERE CONVECTION EXISTS ON FRIDAY
AFTERNOON/EARLY EVENING AS THE COLD FRONT PUSHES THE VERY WARM AND
HUMID AIR MASS OFFSHORE...WITH AT LEAST MODERATE CAPE AND SHEAR. WITH
UNCERTAINTY ON CONVECTIVE DEBRIS...HAVE STAYED CLOSE TO MAV/MET
TEMPS. GENERALLY UPPER 80S/LOWER 90S AREA-WIDE...AND WITH DEWPOINT
POOLING AT LEAST IN THE LOWER 70S...HEAT INDICES IN THE MID TO UPPER
90S FOR MUSH OF THE REGION. MARGINAL HEAT ADVISORY POTENTIAL FOR
NYC/NJ METRO.
THEN SOME UNCERTAINTY FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT IN HOW
FAR OFFSHORE THE COLD FRONT MOVES OFFSHORE AND TIMING OF WEAK WAVES
AND ASSOCIATED AREAS OF PRECIP ALONG THE FRONT. BUT OVERALL WITH
TROUGH AXIS APPROACHING AND FAVORABLE CAPE/SHEAR
ENVIRONMENT...POTENTIAL EXISTS FOR STRONG CONVECTION ACROSS AT LEAST
WESTERN SECTIONS OF THE REGION SAT AFTERNOON/EARLY EVENING.
MODELS IN DECENT AGREEMENT WITH TROUGH AXIS SLIDING EAST SATURDAY
NIGHT...BUT LIKELY GIVING WAY TO MEAN EAST COAST TROUGHING THROUGH
MIDWEEK. AT THE SURFACE BROAD BUT WEAK HIGH PRESSURE BUILDS IN FOR
SUN INTO MON AND THEN PUSHES OFFSHORE ON TUES. THE RESULT WILL NEAR
SEASONABLE CONDITIONS WITH WIDELY SCATTERED DIURNAL CONVECTION SUN
AND MON AFTERNOON.
INCREASING UNCERTAINTY IN DETAILS FOR TUE AND WED...BUT RETURN FLOW
SHOULD ALLOW FOR AN INCREASE IN HUMIDITY LEVELS AND POSSIBLY
INCREASED DIURNAL SHOWER/TSTM COVERAGE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL PASS TO THE SOUTH TONIGHT. A WARM FRONT WILL
APPROACH THU MORNING...AND PASS THROUGH LATE THU MORNING OR EARLY
THU AFTERNOON. A COLD FRONT WILL APPROACH TOWARD THU EVENING.
SHOWERS AND TSTMS DEVELOPING OUT AHEAD OF THE WARM FRONT IN SOUTH
CENTRAL NY AND NORTH CENTRAL PA AS OF 0545Z AND HEADING SOUTHEAST
COULD AFFECT KSWF AND KHPN AFTER 07Z. LOW CONFIDENCE IN SEEING
TSTMS AS THE LINE OF TSTMS IN NORTHERN PA COULD TRACK SOUTH OF
THESE TERMINALS.
WHILE TAFS DO NOT HAVE TSTM IN PREVAILING GROUP...THERE IS A LOW
CHANCE OF TSTMS IMPACTING THE NYC METRO BY 13Z-14Z AND KBDR/KISP
BY 14Z-15Z. TSTMS AT KGON BY 15Z-16Z ADDRESSED WITH PROB30. MVFR
CONDITIONS ARE POSSIBLE IF TSTMS DEVELOP.
WHILE WIDESPREAD TSTM IMPACTS FROM A LINE OF STRONG TO SEVER
TSTMS SHOULD BEGIN AFTER 23Z...SOME DISCRETE TSTMS ARE POSSIBLE
BEFORE THAT BEGINNING ABOUT 20Z-21Z. UNTIL THEN...WIND IMPACTS
WILL BE THE GREATER CONCERN...AS SW WINDS INCREASE QUICKLY AFTER
ABOUT 12Z-13Z...WITH SPEEDS AROUND 15 KT WITH GUSTS 20-25 KT IF
NOT BOTH A LITTLE HIGHER IN NYC METRO.
OUTLOOK FOR 00Z FRI THROUGH MONDAY...
.THU EVENING...LINE OF SEVERE TSTMS WITH STRONG WINDS AND IFR
CONDS EXPECTED.
.LATER THU NIGHT THROUGH MON......OCNL IFR CONDITIONS ARE POSSIBLE
WITH LOW CLOUDS AND/OR SHOWERS/TSTMS.
&&
.MARINE...
WINDS AND SEAS FORECAST ON TRACK OVERNIGHT INTO THURSDAY.
TRANQUIL CONDS ON TAP FOR TONIGHT. TSTMS ARE POSSIBLE THURSDAY
MORNING FROM 10-15Z AS STORM SYSTEM APPROACHES FROM THE WEST.
SCA REMAINS UP FOR ALL WATERS FOR A STRENGTHENING SW FLOW THU AND
THU EVE AHEAD OF POTENT STORM SYSTEM WHICH PASSES TO THE NORTH THU
EVE. GUSTS UP TO 30 POSSIBLE ALONG WITH A LINE OF SEVERE
THUNDERSTORMS DURING THE LATE AFT/EVE HOURS.
SW FLOW EXPECTED TO GRADUALLY WEAKEN ON FRIDAY...BUT MARGINAL SCA
SEAS WILL LIKELY LINGER UNTIL THE COLD FRONT PASSES LATE
FRIDAY/FRIDAY EVENING.
ONCE OCEAN SEAS SUBSIDE...LATE FRIDAY/FRI NIGHT...SUB SCA CONDITIONS
EXPECTED IN A WEAK PRESSURE REGIME THROUGH EARLY NEXT WEEK.
&&
.HYDROLOGY...
NO SIGNIFICANT RAINFALL IS EXPECTED THROUGH TONIGHT.
PRECIPITABLE WATERS ARE FORECAST TO INCREASE TO AROUND 2 INCHES
BY THURSDAY AFTERNOON. AS THE RESULT LOCALLY HEAVY RAINFALL IS
POSSIBLE WITH ANY STRONGER CONVECTION...ESPECIALLY THURSDAY EVENING.
WITH A FORECAST STORM MOTION OF AROUND 20 KT...MINOR URBAN/POOR
DRAINAGE FLOODING IS THE MOST LIKELY THREAT. LOCALIZED FLASH
FLOODING CANNOT BE RULED OUT THOUGH...ESPECIALLY IF TRAINING
OCCURS. FOR NOW FORECASTING BASIN AVERAGE QPF AMOUNTS OF AROUND
1/4 TO 1/2 AN INCH WITH LOCALIZED AMOUNTS OF 1-2+ INCHES POSSIBLE.
MAIN THREAT APPEARS TO BE FOR LOCALLY HEAVY RAINFALL FROM DIURNAL
CONVECTION FRIDAY AND SATURDAY AFTERNOON.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM EDT THIS
EVENING FOR ANZ330-335-338-340-345.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT
FRIDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...NV/DW
NEAR TERM...MPS/DW
SHORT TERM...MPS/DW
LONG TERM...NV
AVIATION...JP
MARINE...NV/DW
HYDROLOGY...MALOIT/MET
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1243 AM EDT THU JUL 26 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS OFFSHORE THIS EVENING AS A POTENT STORM
SYSTEM TRACKS EAST ACROSS THE GREAT LAKES...PASSING TO THE NORTH
ON THURSDAY. A WARM FRONT WILL PASS IN THE MORNING...FOLLOWED BY
A TROUGH OF LOW PRESSURE THURSDAY EVENING. A FRONTAL SYSTEM WILL
SLOWLY PUSH ACROSS AND THEN EAST OF THE REGION FRIDAY THROUGH
SATURDAY NIGHT. WEAK HIGH PRESSURE THEN BUILDS IN SUNDAY INTO THE
BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUDS FROM CONVECTION ACROSS THE GREAT LAKES HAS MOVED INTO THE
REGION. SOUTHERLY FLOW CONTINUES WITH TEMPERATURES IN THE UPPER
60S TO UPPER 70S. ADJUSTED HOURLY TEMPERATURES FOR TRENDS AND ALSO
RAISED OVERNIGHT LOWS A COUPLE OF DEGREES IN SOME OF THE OUTLYING
AREAS THAT WILL NOT FALL WITH THE CLOUD COVER.
GENERALLY DRY CONDS ON TAP FOR THE OVERNIGHT PERIOD AS HIGH PRES
OVERHEAD MOVES OFFSHORE AFTER MIDNIGHT.
STORM SYSTEM DEVELOPING OVER THE OH VALLEY...AND SHORT TERM MODELS
INDICATING EITHER THE SYSTEM OR REMNANTS OF IT WILL APPROACH
WESTERN PORTIONS OF THE FORECAST AREA TOWARDS THE END OF THE
OVERNIGHT PERIOD. LATEST HRRR MODEL HAS ONE WAVE IMPACTING THE
AREA AFTER MIDNIGHT...THEN ANOTHER WAVE APPROACHING FOR AFTER
SUNRISE THURSDAY MORNING. 18Z NAM HAS THE COMPLEX ENTERING WESTERN
PORTIONS OF THE CWA BY 12Z THURSDAY. WILL CARRY SLIGHT CHANCE POPS
FOR ORANGE COUNTY LATE...AND WILL HOLD OFF ON REST OF POPS UNTIL
THE START OF THE SECOND PERIOD.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
WITH EITHER REMNANTS OF OR THE MCS ITSELF APPROACHING THURSDAY
MORNING...WILL GO AHEAD AND INCREASE POPS TO CHANCE STARTING
BETWEEN 10-12Z OVER WESTERN ZONES...THEN WILL SPREAD THOSE POPS
EAST THROUGH 15-17Z. THIS ACTIVITY WILL BE AHEAD OF A WARM FRONT
THAT MOVES NORTH THROUGH THE REGION IN THE MORNING...THEN THE CWA
BECOMES WARM SECTORED IN THE AFTERNOON. WITH LLJ APPROACHING IN
THE MORNING...WILL GO AHEAD AND MENTION GUSTY WINDS IN THE
FORECAST FOR THURSDAY MORNING.
OTHERWISE...AN INITIAL CAP OVER THE AREA IN THE EARLY AFT SHOULD
ERODE WITH A HIGHLY UNSTABLE AIR MASS IN PLACE. MU CAPES OF 2000
TO 3000 J/KG AND 35 TO 40 KT MID LEVEL WINDS WILL SET UP A
FAVORABLE ENVIRONMENT FOR SEVERE WX DURING THE LATE AFTERNOON AND
FIRST HALF OF THE EVENING. CONVERGENCE ALONG AND AHEAD OF THE PRE-
FRONTAL TROF WILL PROVIDE THE LOW-LEVEL FORCING WITH WEAK MID
LEVEL HEIGHT FALLS. THIS FAVORS THE DEVELOPMENT OF A SCATTERED TO
NUMEROUS THUNDERSTORMS. A UNIDIRECTIONAL WIND PROFILE SUPPORTS
MULTIPLE CLUSTERS AND BOWING SEGMENTS WITH THE PRIMARY THREAT
BEING DAMAGING WINDS. SOME WEAKENING OF THE CONVECTION IS EXPECTED
AS IT MOVES OUT ACROSS EASTERN LI AND SE CT. CONVECTION SHOULD
DIMINISH BY MIDNIGHT FROM WEST TO EAST.
AN HWO HAS BEEN UPDATED TO ADDRESS THE SEVERE WEATHER POTENTIAL.
SPC HAS PLACED MOST OF THE AREA UNDER A MODERATE RISK FOR THU AFT
AND EVE. ENHANCED WORDING ADDED TO THE FORECAST TO REFLECT THE
POTENTIAL THESE STORMS WILL HAVE.
PRIOR TO THE ONSET OF THE LATE DAY CONVECTION...A SURGE OF WARM
ALOFT WITH 85H TEMP NEAR 22C WILL ALLOW DAYTIME HIGHS AWAY FROM
THE COAST TO REACH INTO THE LOWER 90S...WITH THE LOW TO MID 80S
ALONG THE COAST. HEAT INDEX VALUES FOR NYC LOOK TO BE JUST BELOW
95.
A WARM...MUGGY NIGHT WILL BE ON TAP THU NIGHT WITH LOW IN THE
LOWER TO MID 70S WITH DEW POINTS AROUND 70. FRONTAL BOUNDARY LOOKS
TO REMAIN JUST NORTH OF THE AREA.
THERE IS A MODERATE RISK OF RIP CURRENTS THURSDAY
MORNING...BECOMING HIGH THURSDAY AFTERNOON THROUGH THURSDAY
EVENING AS WINDS INCREASE TO 15 TO 25 MPH AND SURF BUILDS TO 3 TO
5 FT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
ACTIVE PERIOD TO START THE LONG TERM WITH A GRADUALLY AMPLIFYING
TROUGH WORKING FROM THE GREAT LAKES TO THE EAST COAST THROUGH
SATURDAY NIGHT. MEANWHILE AT THE SURFACE...A SLOW MOVING COLD
FRONT WITH MULTIPLE WEAK WAVES OF LOW PRESSURE WILL GRADUALLY
MOVES ACROSS AND THEN EAST OF THE REGION.
POTENTIAL FOR SCATTERED STRONG TO SEVERE CONVECTION EXISTS ON FRIDAY
AFTERNOON/EARLY EVENING AS THE COLD FRONT PUSHES THE VERY WARM AND
HUMID AIR MASS OFFSHORE...WITH AT LEAST MODERATE CAPE AND SHEAR. WITH
UNCERTAINTY ON CONVECTIVE DEBRIS...HAVE STAYED CLOSE TO MAV/MET
TEMPS. GENERALLY UPPER 80S/LOWER 90S AREA-WIDE...AND WITH DEWPOINT
POOLING AT LEAST IN THE LOWER 70S...HEAT INDICES IN THE MID TO UPPER
90S FOR MUSH OF THE REGION. MARGINAL HEAT ADVISORY POTENTIAL FOR
NYC/NJ METRO.
THEN SOME UNCERTAINTY FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT IN HOW
FAR OFFSHORE THE COLD FRONT MOVES OFFSHORE AND TIMING OF WEAK WAVES
AND ASSOCIATED AREAS OF PRECIP ALONG THE FRONT. BUT OVERALL WITH
TROUGH AXIS APPROACHING AND FAVORABLE CAPE/SHEAR
ENVIRONMENT...POTENTIAL EXISTS FOR STRONG CONVECTION ACROSS AT LEAST
WESTERN SECTIONS OF THE REGION SAT AFTERNOON/EARLY EVENING.
MODELS IN DECENT AGREEMENT WITH TROUGH AXIS SLIDING EAST SATURDAY
NIGHT...BUT LIKELY GIVING WAY TO MEAN EAST COAST TROUGHING THROUGH
MIDWEEK. AT THE SURFACE BROAD BUT WEAK HIGH PRESSURE BUILDS IN FOR
SUN INTO MON AND THEN PUSHES OFFSHORE ON TUES. THE RESULT WILL NEAR
SEASONABLE CONDITIONS WITH WIDELY SCATTERED DIURNAL CONVECTION SUN
AND MON AFTERNOON.
INCREASING UNCERTAINTY IN DETAILS FOR TUE AND WED...BUT RETURN FLOW
SHOULD ALLOW FOR AN INCREASE IN HUMIDITY LEVELS AND POSSIBLY
INCREASED DIURNAL SHOWER/TSTM COVERAGE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL PASS TO THE SOUTH TONIGHT. A WARM FRONT WILL
APPROACH THU MORNING...AND PASS THROUGH LATE THU MORNING OR EARLY
THU AFTERNOON. A COLD FRONT WILL APPROACH TOWARD THU EVENING.
TSTMS DEVELOPING AHEAD OF THE WARM FRONT AS 0F 00Z OVER LOWER
MICHIGAN SHOULD EXPAND AND HEAD E-SE TOWARD THE AREA.
CURRENT THINKING IS THAT THESE STORMS SHOULD REACH KSWF BY 12Z-
13Z...NYC METRO BY 13Z-14Z...KBDR/KISP BY 14Z-15Z...AND KGON BY
15Z-16Z. CONFIDENCE AT LEAST HIGH ENOUGH TO ADDRESS VIA PROB30
GROUP AND TO MENTION MVFR VSBY AT KSWF/KHPN/KBDR.
WHILE WIDESPREAD TSTM IMPACTS FROM A LINE OF STRONG TO SEVER
TSTMS SHOULD BEGIN TOWARD THE VERY END OF THE 00Z TAF PERIOD...
SOME DISCRETE TSTMS ARE POSSIBLE BEFORE THAT BEGINNING ABOUT 20Z-
21Z. UNTIL THEN...WIND IMPACTS WILL BE THE GREATER CONCERN...AS SW
WINDS INCREASE QUICKLY AFTER ABOUT 12Z-13Z...WITH SPEEDS AROUND
15 KT WITH GUSTS 20-25 KT IF NOT BOTH A LITTLE HIGHER IN NYC
METRO.
OUTLOOK FOR 00Z FRI THROUGH MONDAY...
.THU EVENING...LINE OF SEVERE TSTMS WITH STRONG WINDS AND IFR
CONDS EXPECTED.
.LATER THU NIGHT THROUGH MON......OCNL IFR CONDITIONS ARE POSSIBLE
WITH LOW CLOUDS AND/OR SHOWERS/TSTMS.
&&
.MARINE...
WINDS AND SEAS FORECAST ON TRACK OVERNIGHT INTO THURSDAY.
TRANQUIL CONDS ON TAP FOR TONIGHT. TSTMS ARE POSSIBLE THURSDAY
MORNING FROM 10-15Z AS STORM SYSTEM APPROACHES FROM THE WEST.
SCA REMAINS UP FOR ALL WATERS FOR A STRENGTHENING SW FLOW THU AND
THU EVE AHEAD OF POTENT STORM SYSTEM WHICH PASSES TO THE NORTH THU
EVE. GUSTS UP TO 30 POSSIBLE ALONG WITH A LINE OF SEVERE
THUNDERSTORMS DURING THE LATE AFT/EVE HOURS.
SW FLOW EXPECTED TO GRADUALLY WEAKEN ON FRIDAY...BUT MARGINAL SCA
SEAS WILL LIKELY LINGER UNTIL THE COLD FRONT PASSES LATE
FRIDAY/FRIDAY EVENING.
ONCE OCEAN SEAS SUBSIDE...LATE FRIDAY/FRI NIGHT...SUB SCA CONDITIONS
EXPECTED IN A WEAK PRESSURE REGIME THROUGH EARLY NEXT WEEK.
&&
.HYDROLOGY...
NO SIGNIFICANT RAINFALL IS EXPECTED THROUGH TONIGHT.
PRECIPITABLE WATERS ARE FORECAST TO INCREASE TO AROUND 2 INCHES
BY THURSDAY AFTERNOON. AS THE RESULT LOCALLY HEAVY RAINFALL IS
POSSIBLE WITH ANY STRONGER CONVECTION...ESPECIALLY THURSDAY EVENING.
WITH A FORECAST STORM MOTION OF AROUND 20 KT...MINOR URBAN/POOR
DRAINAGE FLOODING IS THE MOST LIKELY THREAT. LOCALIZED FLASH
FLOODING CANNOT BE RULED OUT THOUGH...ESPECIALLY IF TRAINING
OCCURS. FOR NOW FORECASTING BASIN AVERAGE QPF AMOUNTS OF AROUND
1/4 TO 1/2 AN INCH WITH LOCALIZED AMOUNTS OF 1-2+ INCHES POSSIBLE.
MAIN THREAT APPEARS TO BE FOR LOCALLY HEAVY RAINFALL FROM DIURNAL
CONVECTION FRIDAY AND SATURDAY AFTERNOON.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 PM EDT THIS
EVENING FOR ANZ330-335-338-340-345.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT
FRIDAY FOR ANZ350-353-355.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
727 PM CDT FRI JUL 27 2012
.DISCUSSION...CLOUDS ARE INCREASING ACROSS THE REGION THIS
EVENING IN ADVANCE OF A SURFACE LOW ACROSS MONTANA INTO SOUTH
DAKOTA. CURRENTLY THE LOCAL RADARS SHOW ONLY MID LEVEL RETURN NOT
LIKELY REACHING THE GROUND. LATEST RUC MODEL SHOWS PRECIPITATION
ACCUMULATING ACROSS THE SOUTHWEST BY 02-03Z. WITH BOWMAN RADAR
SHOWING LIMITED REFLECTIVITY THIS MAY BE OVERDONE. SO LOW
PROBABILITIES WILL CONTINUE TO SUFFICE WITH 20 TO 40 PERCENT FOR
THE EVENING HOURS SOUTHWEST LOOKING OK. TEMPS AND WINDS LOOK GOOD
BUT NEED TO LOWER DEW POINTS FOR THE EVENING.
&&
.AVIATION...AT 7 PM CDT...LOW PRESSURE WITH AN ASSOCIATED FRONTAL
BOUNDARY EXTENDED ACROSS SOUTHEAST MONTANA INTO WESTERN SOUTH
DAKOTA. THE FRONT WILL BE THE FOCUS FOR SHOWERS AND SCATTERED
THUNDERSTORMS AS IT MOVES EAST TONIGHT AND SATURDAY. VFR
CONDITIONS ARE FORECAST TO CONTINUE THROUGH THE 00Z TAF PERIOD
WITH THE MAIN HAZARD TO AVIATION WIDELY SCATTERED THUNDERSTORMS
THAT WILL POSSIBLY IMPACT KISN/KDIK THROUGH 06Z. WIDELY SCATTERED
TO ISOLATED THUNDERSTORMS ARE FORECAST FOR SATURDAY. AT THIS TIME
THE UNCERTAINTY IS TO GREAT TO MENTION IN THE TAF FORECASTS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
335 PM EDT THU JUL 26 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS SOUTHEAST THROUGH THE OHIO VALLEY THIS
EVENING. A TRAILING LOW PRESSURE SYSTEM WILL CROSS OUR AREA ON
FRIDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE
REGION. BEHIND THIS LOW...HIGH PRESSURE WILL THEN BRING MORE
SEASONABLE TEMPERATURES AND DRIER CONDITIONS FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
ASIDE FROM DROPPING HEAT ADVISORY OVER MUCH OF THE NORTHWEST CWA
AS TEMPERATURES WILL NOT BE ABLE TO RECOVER FROM THE CLOUD COVER
AND OUTFLOW...PREVIOUS DISCUSSION FOR THIS EVENINGS WEATHER IS
UNCHANGED AND STILL VALID AND NOTED BELOW.
SYNOPTICALLY SPEAKING...THE GREAT LAKES AND OHIO VALLEY WILL
REMAIN UNDER A SOUTHWEST TO WEST FLOW ALOFT TODAY INTO TONIGHT. A
COLD FRONT IS FORECAST TO DROP SOUTHEAST INTO THE REGION LATE IN
THE DAY AND MAY HANG UP ACRS THE NRN AREAS OVERNIGHT. LOOKING AT
SATELLITE IMAGERY...IT SHOULD BE NOTED THAT THERE ARE SEVERAL
EMBEDDED DISTURBANCES IN THE SOUTHWEST TO WEST FLOW ALOFT
EXTENDING FROM MISSOURI NORTHEAST INTO THE WESTERN GREAT LAKES.
TWO FEATURES FROM ERN MISSOURI INTO WESTERN ILLINOIS MAY BE THE
IMPETUS TO GET A QLCS GOING ACRS CENTRAL/SOUTH CENTRAL INDIANA
EARLY THIS AFTN. SFC OBSERVATIONS ALSO INDICATE THAT THERE IS A
PREFRONTAL TROF IN THIS REGION AS WELL. IF THIS GETS GOING AS THE
LATEST HRRR INDICATES...IT SHOULD INTENSIFY AS IT MOVES
EAST/SOUTHEAST ACRS OUR REGION DURING THE AFTERNOON AND EVENING
HOURS AS IT FEEDS INTO A VERY UNSTABLE AIRMASS OF 2500-3500 J/KG
OF MLCAPE. IT ALSO WILL HAVE THE ORGANIZATION AND MOMENTUM TO MOVE
QUICKLY AS BULK SHEAR BETWEEN 0=6 KM ARE AROUND 40 KNOTS. GIVEN
THAT FLOW WILL BE MAINLY UNIDIRECTIONAL...FEEL TORNADO THREAT WILL
BE MINIMAL WHILE DAMAGING WINDS AND HAIL SHOULD BE THE MAIN
THREATS. IN FACT...IT IS THE DAMAGING WIND POTENTIAL THAT WILL
LIKELY BE THE HIGHEST IMPACT DUE TO 50 KNOT MID LEVEL JET MOVING
ACRS THE REGION...STEEP LOW LEVEL LAPSE RATES...DELTA THREAT E
VALUES OF 25 KELVIN AND DCAPES OF 1000-1500 J/KG. ALTHOUGH TREE
DAMAGE AND POWER OUTAGES MAY OCCUR...ATTM...WE EXPECT THIS FEATURE
TO BEHAVE MORE LIKE A QLCS/BOW ECHO FEATURE AND NOT MIMIC THE JUNE
29 DERECHO THAT CAUSED EXTENSIVE/WIDESPREAD DAMAGE OVER MOST OF
THE ENTIRE REGION. THAT SAID...THERE WILL BE WIND DAMAGE AND OF
COURSE THERE COULD BE POCKETS OF ENHANCED WIND DAMAGE WITH ANY
OUTFLOW/GUST FRONT OR MICROBURST. THUS...THE SPC HAS KEPT MOST OF
OUR AREA IN A MODERATE RISK FOR SEVERE THUNDERSTORMS. PWATS WILL BE
HIGH...IN EXCESS OF 2 INCHES...WITH THE THUNDERSTORM ACTIVITY SO
LOCALLY HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE BUT
SHOULD BE LIMITED GIVEN THE SPEED AT WHICH STORMS WILL BE MOVING.
A HOT AND HUMID AIRMASS WILL BE IN PLACE FOR THESE THUNDERSTORMS
TO FEED ON. GIVEN THE AMOUNT OF SUNSHINE OCCURRING OVER THE ERN/SRN
AREAS THIS MORNING...AND THE FACT THAT KILN SOUNDING AND MODEL
SOUNDINGS INDICATE THAT 850 MB TEMPS WILL BE IN THE 23-24 C
RANGE...BELIEVE A GOOD CHUNK OF THIS REGION WILL SEE TEMPERATURES
PEAK INTO THE MID AND UPPER 90S WITH DEWPOINTS IN THE LOWER 70S.
THIS WILL PUSH HEAT INDICES INTO THE 105 TO 108 DEGREE RANGE. AS
SUCH...HAVE UPGRADED THIS REGION TO AN EXCESSIVE HEAT WARNING PER
LOCAL CRITERIA OF A HEAT INDEX OF 105. THE REMAINDER OF THE
REGION...EXCEPT MONTGOMERY COUNTY...REMAINS UNDER A HEAT ADVISORY
FOR HEAT INDICES RANGING FROM 100 TO 104. IT MUST BE NOTED THAT
SHOWERS AND STORMS WILL LIKELY COOL THINGS OFF SIGNIFICANTLY AND
THE HEAT ADVISORY/EXCESSIVE HEAT WARNING WILL LIKELY COME DOWN
BEFORE THE 8 PM EDT DEADLINE.
&&
.SHORT TERM /MIDNIGHT TONIGHT THROUGH FRIDAY NIGHT/...
DID NOT MAKE SWEEPING CHANGES TO THE TEMPERATURE FORECAST FOR THE
NEXT 3 PERIODS BUT DID LOWER HIGHS A BIT IN THE NORTHWEST ON
FRIDAY.
LOWERED POPS TONIGHT BY A BUNCH IN THE 6-12Z TIME FRAME AND EXPECT
THINGS TO RAMP UP QUICKLY TOMORROW MORNING AS THE PROXIMITY OF THE
LOW INTERACTS WITH A RECEPTIVE ATMOSPHERE WITH THE INTRODUCTION OF
DAYTIME HEATING. FEEL THAT THE 3-6Z TIME FRAME THIS EVENING IS A
LITTLE OVERDONE WITH THE CONTINUED HIGHER CHANCES OF RAIN BUT WILL
WAIT UNTIL THE FIRST ROUND OF SEVERE WEATHER CROSSES BEFORE I AM
COMFORTABLE ENOUGH TO SOUND THE ALL CLEAR...PARTICULARLY IN THE
NORTHWEST.
DECREASED THE CHANCE FOR RAIN SIGNIFICANTLY TOMORROW NIGHT ACROSS
THE BOARD AS DRIER AIR WILL FILTER IN BEHIND THE LOW.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
FOR SATURDAY THROUGH MONDAY...MODELS AND ENSEMBLES AT LEAST AGREE
ON THE UPPER LEVEL PATTERN...WITH REGION SITUATED ON EASTERN SIDE
OF PLAINS/ROCKIES RIDGE. FOR SATURDAY...THE COLD FRONT WILL BE TO
OUR EAST...WITH A SFC LOW EXITING NEW ENGLAND. SOME OF THE MODELS
ARE INDICATING A SECONDARY SFC REFLECTION DEVELOPING AS A
SHORTWAVE TROUGH DIVES THROUGH THE GREAT LAKES. COMBINED WITH WEAK
INSTBY...THIS COULD SPARK A FEW SHOWERS/STORMS OVER THE UPPER OHIO
VALLEY. SO HAVE MAINTAINED THE 20 POPS OVER OUR EASTERN TIER OR
TWO OF COUNTIES DURING THE AFTERNOON. OTHERWISE SFC HIGH PRESSURE
WILL BE BUILDING IN FROM THE WEST WITH COOLER AND DRIER AIR
ADVECTING INTO THE CWA. SUNDAY HAS THE HIGHEST FORECAST CONFIDENCE
AS SFC HIGH PRESSURE BUILDS DIRECTLY OVER THE CWA. TEMPERATURES
WILL BE NEAR OR SLIGHTLY BELOW SEASONABLE VALUES WITH FAIRLY LOW
HUMIDITY.
THE GFS TAKES A MORE SLIGHTLY MORE AMPLIFIED TURN BEGINNING
MONDAY...WITH PROJECTIONS OF A DEEPENING EAST COAST LONGWAVE TROUGH.
HOWEVER MODELS REMAIN IN CLOSE ENOUGH AGREEMENT TO TAKE AN ENSEMBLE
APPROACH WITH THE FORECAST. THERE IS CONTINUED AGREEMENT THAT
TUESDAY WILL HAVE THE HIGHEST PCPN CHANCES...AS A SFC BOUNDARY/UPPER
WAVE SAGS DOWN INTO THE AREA. SOME ACTIVITY MAY REACH THE NORTHWEST
BY MONDAY AFTERNOON...AND LINGER INTO WEDNESDAY DEPENDING ON THE
TIMING OF THE DISTURBANCES IN THE NORTHWEST FLOW. AT THIS
TIME...WEAK HIGH PRESSURE IS ANTICIPATED FOR THURSDAY. TEMPERATURES
WILL RISE SLIGHTLY BEGINNING MONDAY...BUT SHOULD NOT VARY
SIGNIFICANTLY FROM AVERAGE THROUGH THE WEEK WITH THE HEAT DOME
REMAINING WELL TO OUR WEST.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
UNDER A SOUTHWEST TO WEST FLOW ALOFT...A COLD FRONT WILL SAG
SOUTHEAST INTO THE NRN REACHES OF THE FORECAST AREA OVERNIGHT WHERE
IT WILL LIKELY STALL OUT. OTHERWISE...SHOWER AND THUNDERSTORM
PROBABILITIES WILL BE HIGH THIS AFTERNOON AND EVENING AS
CLUSTERS/LINES OF THUNDERSTORMS MOVE E/SE ACRS THE REGION. THE
MAIN THREAT WILL BE DAMAGING WINDS. MODE OF THUNDERSTORMS ARE
STILL UNCLEAR AT THIS POINT...SO HAVE NOT TRIED TO PINPOINT WIND
STRENGTH AT THE TAFS...KNOWING THAT AMENDMENTS WILL HAVE TO BE
EMPLOYED IF AND WHEN IT BECOMES NECESSARY. LOCALLY HEAVY RAIN WITH
IFR VSBYS AND MVFR CIGS WILL LIKELY OCCUR.
FOR THE OVERNIGHT PERIOD...MODELS SUGGEST THAT DEEPER MOISTURE AND
FORCING WILL SHIFT E/SE OF THE TAF SITES...LEAVING MAINLY A DRY
PERIOD OVERNIGHT. WILL GO WITH VFR CONDITIONS DURING THIS PERIOD.
ON FRIDAY...A DISTURBANCE WILL DIG SE TOWARD THE GREAT LAKES
REGION. THIS WILL PERTURB A WAVE OF LOW PRESSURE ALONG STALLED
OUT FRONTAL BOUNDARY. MOISTURE AND INSTABILITY ASSOCIATED WITH THE
LOW AND DISTURBANCE WILL RESULT IN CONVECTION DURING THE AFTN AND
EVENING HOURS ONCE AGAIN.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE THROUGH FRIDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ070-071.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR OHZ055-
056-061-063>065-072>074-077>082-088.
KY...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR
KYZ089>100.
IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ066-073-074.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR INZ075-
080.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...FRANKS
LONG TERM...SNYDER
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
119 PM EDT THU JUL 26 2012
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL GIVE WAY TO STRONG TO SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING AS A COLD FRONT MOVES
SOUTHEAST TOWARD THE OHIO VALLEY. THE FRONT WILL PUSH INTO THE
AREA TONIGHT AND A LOW PRESSURE SYSTEM WILL CROSS OUR AREA ON
FRIDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE
REGION. HIGH PRESSURE WILL THEN BRING MORE SEASONABLE TEMPERATURES
AND DRIER CONDITIONS FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THERE IS MUCH TO TALK ABOUT ON WHAT SHOULD BE AN ACTIVE SEVERE
EVENT THIS AFTERNOON AND EVENING ACRS OUR REGION.
SYNOPTICALLY SPEAKING...THE GREAT LAKES AND OHIO VALLEY WILL
REMAIN UNDER A SOUTHWEST TO WEST FLOW ALOFT TODAY INTO TONIGHT. A
COLD FRONT IS FORECAST TO DROP SOUTHEAST INTO THE REGION LATE IN
THE DAY AND MAY HANG UP ACRS THE NRN AREAS OVERNIGHT. LOOKING AT
SATELLITE IMAGERY...IT SHOULD BE NOTED THAT THERE ARE SEVERAL
EMBEDDED DISTURBANCES IN THE SOUTHWEST TO WEST FLOW ALOFT
EXTENDING FROM MISSOURI NORTHEAST INTO THE WESTERN GREAT LAKES.
TWO FEATURES FROM ERN MISSOURI INTO WESTERN ILLINOIS MAY BE THE
IMPETUS TO GET A QLCS GOING ACRS CENTRAL/SOUTH CENTRAL INDIANA
EARLY THIS AFTN. SFC OBSERVATIONS ALSO INDICATE THAT THERE IS A
PREFRONTAL TROF IN THIS REGION AS WELL. IF THIS GETS GOING AS THE
LATEST HRRR INDICATES...IT SHOULD INTENSIFY AS IT MOVES
EAST/SOUTHEAST ACRS OUR REGION DURING THE AFTERNOON AND EVENING
HOURS AS IT FEEDS INTO A VERY UNSTABLE AIRMASS OF 2500-3500 J/KG
OF MLCAPE. IT ALSO WILL HAVE THE ORGANIZATION AND MOMENTUM TO MOVE
QUICKLY AS BULK SHEAR BETWEEN 0=6 KM ARE AROUND 40 KNOTS. GIVEN
THAT FLOW WILL BE MAINLY UNIDIRECTIONAL...FEEL TORNADO THREAT WILL
BE MINIMAL WHILE DAMAGING WINDS AND HAIL SHOULD BE THE MAIN
THREATS. IN FACT...IT IS THE DAMAGING WIND POTENTIAL THAT WILL
LIKELY BE THE HIGHEST IMPACT DUE TO 50 KNOT MID LEVEL JET MOVING
ACRS THE REGION...STEEP LOW LEVEL LAPSE RATES...DELTA THREAT E
VALUES OF 25 KELVIN AND DCAPES OF 1000-1500 J/KG. ALTHOUGH TREE
DAMAGE AND POWER OUTAGES MAY OCCUR...ATTM...WE EXPECT THIS FEATURE
TO BEHAVE MORE LIKE A QLCS/BOW ECHO FEATURE AND NOT MIMIC THE JUNE
29 DERECHO THAT CAUSED EXTENSIVE/WIDESPREAD DAMAGE OVER MOST OF
THE ENTIRE REGION. THAT SAID...THERE WILL BE WIND DAMAGE AND OF
COURSE THERE COULD BE POCKETS OF ENHANCED WIND DAMAGE WITH ANY
OUTFLOW/GUST FRONT OR MICROBURST. THUS...THE SPC HAS KEPT MOST OF
OUR AREA IN A MODERATE RISK FOR SEVERE THUNDERSTORMS. PWATS WILL BE
HIGH...IN EXCESS OF 2 INCHES...WITH THE THUNDERSTORM ACTIVITY SO
LOCALLY HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE BUT
SHOULD BE LIMITED GIVEN THE SPEED AT WHICH STORMS WILL BE MOVING.
A HOT AND HUMID AIRMASS WILL BE IN PLACE FOR THESE THUNDERSTORMS
TO FEED ON. GIVEN THE AMOUNT OF SUNSHINE OCCURRING OVER THE ERN/SRN
AREAS THIS MORNING...AND THE FACT THAT KILN SOUNDING AND MODEL
SOUNDINGS INDICATE THAT 850 MB TEMPS WILL BE IN THE 23-24 C
RANGE...BELIEVE A GOOD CHUNK OF THIS REGION WILL SEE TEMPERATURES
PEAK INTO THE MID AND UPPER 90S WITH DEWPOINTS IN THE LOWER 70S.
THIS WILL PUSH HEAT INDICES INTO THE 105 TO 108 DEGREE RANGE. AS
SUCH...HAVE UPGRADED THIS REGION TO AN EXCESSIVE HEAT WARNING PER
LOCAL CRITERIA OF A HEAT INDEX OF 105. THE REMAINDER OF THE
REGION...EXCEPT MONTGOMERY COUNTY...REMAINS UNDER A HEAT ADVISORY
FOR HEAT INDICES RANGING FROM 100 TO 104. IT MUST BE NOTED THAT
SHOWERS AND STORMS WILL LIKELY COOL THINGS OFF SIGNIFICANTLY AND
THE HEAT ADVISORY/EXCESSIVE HEAT WARNING WILL LIKELY COME DOWN
BEFORE THE 8 PM EDT DEADLINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CONVECTION WILL SHIFT SOUTHEAST LATE THIS EVENING AND WITH THE
LOSS OF DAYTIME HEATING...WILL GRADUALLY LOSE IT/S INTENSITY.
HOWEVER...STORMS WILL STILL BE INTENSE ENOUGH TO PRODUCE SEVERE
WEATHER AT LEAST THROUGH THE FIRST PART OF THE OVERNIGHT PERIOD.
HAVE THEREFORE KEPT THE MENTION OF SEVERE STORMS IN THE GRIDS
THROUGH 03Z. BY THAT TIME...MOST ACTIVITY WILL HAVE SHIFTED TO OUR
SOUTHEASTERN ZONES. THERE...SOME ONGOING CONVECTIVE ACTIVITY COULD
POSE ADDITIONAL FLOOD ISSUES ALONG AND SOUTH OF THE OHIO RIVER
SHOULD THUNDERSTORMS BEGIN TO TRAIN OVER THE SAME LOCATIONS LATE
TONIGHT.
ON FRIDAY THERE ARE STILL SOME DIFFERENCES ON HOW THE MODELS HANDLE
THE SHORTWAVE PIVOTING ACROSS THE GREAT LAKES. THE SREF AND NAM
DEVELOP A WEAK CLOSED SURFACE LOW AHEAD OF THE TROUGH AND DIVE IT
SOUTHWARD TOWARD OUR AREA. THIS WOULD PRODUCE A ROUND OF AFTERNOON
CONVECTION FOR THE EASTERN TWO THIRDS OF THE FORECAST AREA. THE
ARW AND NMM BOTH AGREE WITH THIS SOLUTION. HAVE FORECAST 50/50 POPS
FOR MUCH OF THE AREA FOR FRIDAY AFTERNOON TO REFLECT THIS. DID NOT
GO LIKELY ON POPS SINCE THE ECMWF STILL DOES NOT AGREE WITH THIS
SOLUTION.
REGARDLESS OF WHICH MODEL YOU CHOOSE FROM...COLD ADVECTION FINALLY
STABILIZES US FRIDAY NIGHT AS HIGH PRESSURE BEGINS TO BUILD ACROSS
THE OHIO VALLEY. A FEW RESIDUAL SHOWERS AND THUNDERSTORMS COULD
LINGER INTO SATURDAY ACROSS THE EAST AS THE SFC LOW DEPARTS.
SATURDAY THROUGH SATURDAY NIGHT WILL MARK A RETURN TO MORE
SEASONABLE TEMPERATURES AS THE SFC HIGH PRESSURE SETTLES ACROSS
THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY IS PROBABLY THE DAY WITH HIGHEST FORECAST CONFIDENCE AS
SFC HIGH PRESSURE BUILDS OVER THE CWA. TEMPERATURES WILL BE
SEASONABLE WITH FAIRLY LOW HUMIDITY.
THE GFS/NCEP MODELS TAKES A MORE AMPLIFIED TURN BEGINNING
MONDAY...WITH 500 MB HEIGHTS AT ILN RESIDING ON THE LOW END OF NAEFS
SPREAD BY MID WEEK. THIS AFFECTS PCPN FORECASTS MORE THAN
TEMPERATURES HOWEVER OVER THE LOCAL AREA (AS 00Z AND 12Z ECMWF HOLD
A STRONGER SFC RIDGE IN PLACE). TOOK AN ENSEMBLE APPROACH WITH THE
FORECAST...WHICH DID NOT SIGNIFICANTLY CHANGE THE GOING FORECAST.
TUESDAY WILL HAVE THE HIGHEST PCPN CHANCES...SUPPORTED BY
ENSEMBLES...AS WELL AS A SFC BDY/UPPER WAVE THAT MAY SAG DOWN INTO
THE AREA. CANNOT TOTALLY RULE OUT PCPN MONDAY/WEDNESDAY BUT LIMITED
TO 20 POPS. TEMPERATURES WILL RISE SOME AS LOW LEVEL FLOW BECOME
MORE SOUTHERLY...BUT AT THIS TIME LOOK TO REMAIN WITHIN 5 DEGREES OF
NORMAL. HUMIDITY WILL ALSO INCREASE SLIGHTLY...HOLDING UP OVERNIGHT
LOWS.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
UNDER A SOUTHWEST TO WEST FLOW ALOFT...A COLD FRONT WILL SAG
SOUTHEAST INTO THE NRN REACHES OF THE FORECAST AREA OVERNIGHT WHERE
IT WILL LIKELY STALL OUT. OTHERWISE...SHOWER AND THUNDERSTORM
PROBABILITIES WILL BE HIGH THIS AFTERNOON AND EVENING AS
CLUSTERS/LINES OF THUNDERSTORMS MOVE E/SE ACRS THE REGION. THE
MAIN THREAT WILL BE DAMAGING WINDS. MODE OF THUNDERSTORMS ARE
STILL UNCLEAR AT THIS POINT...SO HAVE NOT TRIED TO PINPOINT WIND
STRENGTH AT THE TAFS...KNOWING THAT AMENDMENTS WILL HAVE TO BE
EMPLOYED IF AND WHEN IT BECOMES NECESSARY. LOCALLY HEAVY RAIN WITH
IFR VSBYS AND MVFR CIGS WILL LIKELY OCCUR.
FOR THE OVERNIGHT PERIOD...MODELS SUGGEST THAT DEEPER MOISTURE AND
FORCING WILL SHIFT E/SE OF THE TAF SITES...LEAVING MAINLY A DRY
PERIOD OVERNIGHT. WILL GO WITH VFR CONDITIONS DURING THIS PERIOD.
ON FRIDAY...A DISTURBANCE WILL DIG SE TOWARD THE GREAT LAKES
REGION. THIS WILL PERTURB A WAVE OF LOW PRESSURE ALONG STALLED
OUT FRONTAL BOUNDARY. MOISTURE AND INSTABILITY ASSOCIATED WITH THE
LOW AND DISTURBANCE WILL RESULT IN CONVECTION DURING THE AFTN AND
EVENING HOURS ONCE AGAIN.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE THROUGH FRIDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ026-034-035-
042>046-051>054-060-062-070-071.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR OHZ055-
056-061-063>065-072>074-077>082-088.
KY...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR
KYZ089>100.
IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ050-058-059-
066-073-074.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR INZ075-
080.
&&
$$
SYNOPSIS...HICKMAN/LATTO
NEAR TERM...HICKMAN/LATTO
SHORT TERM...HICKMAN/LATTO
LONG TERM...SNYDER
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1131 AM EDT THU JUL 26 2012
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL GIVE WAY TO STRONG TO SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING AS A COLD FRONT MOVES
SOUTHEAST TOWARD THE OHIO VALLEY. THE FRONT WILL PUSH INTO THE
AREA TONIGHT AND A LOW PRESSURE SYSTEM WILL CROSS OUR AREA ON
FRIDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE
REGION. HIGH PRESSURE WILL THEN BRING MORE SEASONABLE TEMPERATURES
AND DRIER CONDITIONS FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THERE IS MUCH TO TALK ABOUT ON WHAT SHOULD BE AN ACTIVE SEVERE
EVENT THIS AFTERNOON AND EVENING ACRS OUR REGION.
SYNOPTICALLY SPEAKING...THE GREAT LAKES AND OHIO VALLEY WILL
REMAIN UNDER A SOUTHWEST TO WEST FLOW ALOFT TODAY INTO TONIGHT. A
COLD FRONT IS FORECAST TO DROP SOUTHEAST INTO THE REGION LATE IN
THE DAY AND MAY HANG UP ACRS THE NRN AREAS OVERNIGHT. LOOKING AT
SATELLITE IMAGERY...IT SHOULD BE NOTED THAT THERE ARE SEVERAL
EMBEDDED DISTURBANCES IN THE SOUTHWEST TO WEST FLOW ALOFT
EXTENDING FROM MISSOURI NORTHEAST INTO THE WESTERN GREAT LAKES.
TWO FEATURES FROM ERN MISSOURI INTO WESTERN ILLINOIS MAY BE THE
IMPETUS TO GET A QLCS GOING ACRS CENTRAL/SOUTH CENTRAL INDIANA
EARLY THIS AFTN. SFC OBSERVATIONS ALSO INDICATE THAT THERE IS A
PREFRONTAL TROF IN THIS REGION AS WELL. IF THIS GETS GOING AS THE
LATEST HRRR INDICATES...IT SHOULD INTENSIFY AS IT MOVES
EAST/SOUTHEAST ACRS OUR REGION DURING THE AFTERNOON AND EVENING
HOURS AS IT FEEDS INTO A VERY UNSTABLE AIRMASS OF 2500-3500 J/KG
OF MLCAPE. IT ALSO WILL HAVE THE ORGANIZATION AND MOMENTUM TO MOVE
QUICKLY AS BULK SHEAR BETWEEN 0=6 KM ARE AROUND 40 KNOTS. GIVEN
THAT FLOW WILL BE MAINLY UNIDIRECTIONAL...FEEL TORNADO THREAT WILL
BE MINIMAL WHILE DAMAGING WINDS AND HAIL SHOULD BE THE MAIN
THREATS. IN FACT...IT IS THE DAMAGING WIND POTENTIAL THAT WILL
LIKELY BE THE HIGHEST IMPACT DUE TO 50 KNOT MID LEVEL JET MOVING
ACRS THE REGION...STEEP LOW LEVEL LAPSE RATES...DELTA THREAT E
VALUES OF 25 KELVIN AND DCAPES OF 1000-1500 J/KG. ALTHOUGH TREE
DAMAGE AND POWER OUTAGES MAY OCCUR...ATTM...WE EXPECT THIS FEATURE
TO BEHAVE MORE LIKE A QLCS/BOW ECHO FEATURE AND NOT MIMIC THE JUNE
29 DERECHO THAT CAUSED EXTENSIVE/WIDESPREAD DAMAGE OVER MOST OF
THE ENTIRE REGION. THAT SAID...THERE WILL BE WIND DAMAGE AND OF
COURSE THERE COULD BE POCKETS OF ENHANCED WIND DAMAGE WITH ANY
OUTFLOW/GUST FRONT OR MICROBURST. THUS...THE SPC HAS KEPT MOST OF
OUR AREA IN A MODERATE RISK FOR SEVERE THUNDERSTORMS. PWATS WILL BE
HIGH...IN EXCESS OF 2 INCHES...WITH THE THUNDERSTORM ACTIVITY SO
LOCALLY HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE BUT
SHOULD BE LIMITED GIVEN THE SPEED AT WHICH STORMS WILL BE MOVING.
A HOT AND HUMID AIRMASS WILL BE IN PLACE FOR THESE THUNDERSTORMS
TO FEED ON. GIVEN THE AMOUNT OF SUNSHINE OCCURRING OVER THE ERN/SRN
AREAS THIS MORNING...AND THE FACT THAT KILN SOUNDING AND MODEL
SOUNDINGS INDICATE THAT 850 MB TEMPS WILL BE IN THE 23-24 C
RANGE...BELIEVE A GOOD CHUNK OF THIS REGION WILL SEE TEMPERATURES
PEAK INTO THE MID AND UPPER 90S WITH DEWPOINTS IN THE LOWER 70S.
THIS WILL PUSH HEAT INDICES INTO THE 105 TO 108 DEGREE RANGE. AS
SUCH...HAVE UPGRADED THIS REGION TO AN EXCESSIVE HEAT WARNING PER
LOCAL CRITERIA OF A HEAT INDEX OF 105. THE REMAINDER OF THE
REGION...EXCEPT MONTGOMERY COUNTY...REMAINS UNDER A HEAT ADVISORY
FOR HEAT INDICES RANGING FROM 100 TO 104. IT MUST BE NOTED THAT
SHOWERS AND STORMS WILL LIKELY COOL THINGS OFF SIGNIFICANTLY AND
THE HEAT ADVISORY/EXCESSIVE HEAT WARNING WILL LIKELY COME DOWN
BEFORE THE 8 PM EDT DEADLINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CONVECTION WILL SHIFT SOUTHEAST LATE THIS EVENING AND WITH THE
LOSS OF DAYTIME HEATING...WILL GRADUALLY LOSE IT/S INTENSITY.
HOWEVER...STORMS WILL STILL BE INTENSE ENOUGH TO PRODUCE SEVERE
WEATHER AT LEAST THROUGH THE FIRST PART OF THE OVERNIGHT PERIOD.
HAVE THEREFORE KEPT THE MENTION OF SEVERE STORMS IN THE GRIDS
THROUGH 03Z. BY THAT TIME...MOST ACTIVITY WILL HAVE SHIFTED TO OUR
SOUTHEASTERN ZONES. THERE...SOME ONGOING CONVECTIVE ACTIVITY COULD
POSE ADDITIONAL FLOOD ISSUES ALONG AND SOUTH OF THE OHIO RIVER
SHOULD THUNDERSTORMS BEGIN TO TRAIN OVER THE SAME LOCATIONS LATE
TONIGHT.
ON FRIDAY THERE ARE STILL SOME DIFFERENCES ON HOW THE MODELS HANDLE
THE SHORTWAVE PIVOTING ACROSS THE GREAT LAKES. THE SREF AND NAM
DEVELOP A WEAK CLOSED SURFACE LOW AHEAD OF THE TROUGH AND DIVE IT
SOUTHWARD TOWARD OUR AREA. THIS WOULD PRODUCE A ROUND OF AFTERNOON
CONVECTION FOR THE EASTERN TWO THIRDS OF THE FORECAST AREA. THE
ARW AND NMM BOTH AGREE WITH THIS SOLUTION. HAVE FORECAST 50/50 POPS
FOR MUCH OF THE AREA FOR FRIDAY AFTERNOON TO REFLECT THIS. DID NOT
GO LIKELY ON POPS SINCE THE ECMWF STILL DOES NOT AGREE WITH THIS
SOLUTION.
REGARDLESS OF WHICH MODEL YOU CHOOSE FROM...COLD ADVECTION FINALLY
STABILIZES US FRIDAY NIGHT AS HIGH PRESSURE BEGINS TO BUILD ACROSS
THE OHIO VALLEY. A FEW RESIDUAL SHOWERS AND THUNDERSTORMS COULD
LINGER INTO SATURDAY ACROSS THE EAST AS THE SFC LOW DEPARTS.
SATURDAY THROUGH SATURDAY NIGHT WILL MARK A RETURN TO MORE
SEASONABLE TEMPERATURES AS THE SFC HIGH PRESSURE SETTLES ACROSS
THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY IS PROBABLY THE DAY WITH HIGHEST FORECAST CONFIDENCE AS
SFC HIGH PRESSURE BUILDS OVER THE CWA. TEMPERATURES WILL BE
SEASONABLE WITH FAIRLY LOW HUMIDITY.
THE GFS/NCEP MODELS TAKES A MORE AMPLIFIED TURN BEGINNING
MONDAY...WITH 500 MB HEIGHTS AT ILN RESIDING ON THE LOW END OF NAEFS
SPREAD BY MID WEEK. THIS AFFECTS PCPN FORECASTS MORE THAN
TEMPERATURES HOWEVER OVER THE LOCAL AREA (AS 00Z AND 12Z ECMWF HOLD
A STRONGER SFC RIDGE IN PLACE). TOOK AN ENSEMBLE APPROACH WITH THE
FORECAST...WHICH DID NOT SIGNIFICANTLY CHANGE THE GOING FORECAST.
TUESDAY WILL HAVE THE HIGHEST PCPN CHANCES...SUPPORTED BY
ENSEMBLES...AS WELL AS A SFC BDY/UPPER WAVE THAT MAY SAG DOWN INTO
THE AREA. CANNOT TOTALLY RULE OUT PCPN MONDAY/WEDNESDAY BUT LIMITED
TO 20 POPS. TEMPERATURES WILL RISE SOME AS LOW LEVEL FLOW BECOME
MORE SOUTHERLY...BUT AT THIS TIME LOOK TO REMAIN WITHIN 5 DEGREES OF
NORMAL. HUMIDITY WILL ALSO INCREASE SLIGHTLY...HOLDING UP OVERNIGHT
LOWS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT ARE CONTINUING TO
WORK THEIR WAY SLOWLY EAST THIS MORNING ACROSS ILLINOIS INTO
NORTHWEST INDIANA. AN OUTFLOW BOUNDARY FROM THESE STORMS IS NOW
EVIDENT ON REGIONAL RADARS STRETCHING FROM NORTHEAST INDIANA DOWN
INTO WEST CENTRAL INDIANA. QUESTIONS REMAIN AS TO WHAT WILL HAPPEN
WITH THIS BOUNDARY AS IT PUSHES EAST INTO OUR AREA THROUGH MID TO
LATE MORNING. THE AIRMASS ACROSS OUR AREA REMAINS UNSTABLE AT
LEAST ALOFT AND WITH SURFACE TEMPS STILL IN THE LOW 80S...NOT SURE
THE DEGREE OF LOW LEVEL INHIBITION PRESENT. SEVERAL OF THE LATEST
HI RES MODELS ARE TRYING TO INDICATE SOME SPOTTY SHOWER
DEVELOPMENT ASSOCIATED WITH THIS BOUNDARY OVER THE NEXT SEVERAL
HOURS. HOWEVER...THIS CHANCE APPEARS FAIRLY LOW AT THIS POINT SO
WILL MAINTAIN A DRY FORECAST THIS MORNING. WE SHOULD DESTABILIZE
FURTHER THROUGH THIS AFTERNOON AND AS BETTER FORCING ARRIVES AHEAD
OF THE APPROACHING COLD FRONT...EXPECT SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH MID AFTERNOON. SHOWER ACTIVITY SHOULD MOVE OFF
TO THE SOUTHEAST THROUGH LATE AFTERNOON BUT WILL LIKELY SEE A
SECONDARY AREA OF CONVECTION DEVELOP THROUGH EARLY EVENING AS MID
LEVEL TROUGH AXIS APPROACHES. AHEAD OF THE FRONT...EXPECT SOME
GUSTY SOUTHWEST WINDS TO DEVELOP LATER THIS MORNING INTO THIS
AFTERNOON. IN ADDITION...STRONGER WIND GUSTS WILL BE POSSIBLE WITH
CONVECTIVE STORMS. TSTM ACTIVITY SHOULD TAPER OFF LATER THIS
EVENING AND IF WE ARE ABLE TO SCATTER OUT....WE COULD SEE SOME
AREAS OF BR DEVELOP LATER TONIGHT.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE THROUGH FRIDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ026-034-035-
042>046-051>054-060-062-070-071.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR OHZ055-
056-061-063>065-072>074-077>082-088.
KY...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR
KYZ089>100.
IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ050-058-059-
066-073-074.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR INZ075-
080.
&&
$$
SYNOPSIS...HICKMAN/LATTO
NEAR TERM...HICKMAN/LATTO
SHORT TERM...HICKMAN/LATTO
LONG TERM...SNYDER
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
606 AM EDT THU JUL 26 2012
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL GIVE WAY TO STRONG TO SEVERE
THUNDERSTORMS TODAY AS A COLD FRONT MOVES SOUTHWEST TOWARD THE
OHIO VALLEY. THE FRONT WILL PUSH THROUGH THE AREA TONIGHT AND A
LOW PRESSURE SYSTEM WILL CROSS OUR AREA ON FRIDAY...BRINGING
ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE REGION. HIGH PRESSURE
WILL THEN BRING MORE SEASONABLE TEMPERATURES AND DRIER CONDITIONS
FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STEADY WARM ADVECTION UNDER SOUTHWEST FLOW WILL CONTINUE THROUGH
SUNRISE. OUTFLOW FROM CONVECTION TO OUR NORTHWEST IS TRIGGERING
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF ILLINOIS AND INDIANA.
SOME OF THESE STORMS WILL HOLD TOGETHER AND MAKE IT TO OUR WESTERN
ZONES JUST AFTER SUNRISE THIS MORNING. AS THIS ACTIVITY OUTRUNS
THE FRONTAL FORCING...AND WE ENTER THE DIURNAL MINIMUM FOR
CONVECTION...ANY REMAINING SHOWERS/THUNDERSTORMS WILL DIMINISH BY
MID MORNING. HAVE THEREFORE FORECAST A LULL IN ANY POPS DURING
THE MID MORNING UNTIL EARLY AFTERNOON. THIS FORECAST TO START OFF
THE DAY BEST RESEMBLES THE HRRR AND SREF. HAVE AVOIDED USING THE 00Z
ARW AND SPC WRF FOR THIS PACKAGE...AS THEY APPEAR TO BRING AN
INITIATION OF TOO MUCH CONVECTION TOO FAR EAST...TOO EARLY IN THE
DAY. THIS IS LIKELY DUE TO THE HANDLING OF THE AFOREMENTIONED
OUTFLOW BOUNDARY INTERACTING WITH OUR UNSTABLE AIRMASS...AND NOT
THE DEVELOPMENT OF THE MORE INTENSE...SYNOPTICALLY FORCED
CONVECTION THAT WILL OCCUR LATE THIS AFTERNOON.
WITH ONGOING WARM ADVECTION AND INCREASING SOUTHERLY FLOW TO START
OFF THE DAY...THE BOUNDARY LAYER WILL BE WELL MIXED. TEMPERATURES
OF 20 TO 21 C AT 850 HPA...UNDER PARTLY CLOUDY SKIES...WILL BRING
SURFACE TEMPERATURES QUICKLY INTO THE LOW 90S BY THE EARLY
AFTERNOON. THESE WARM TEMPERATURES WILL COMBINE WITH DEWPOINTS IN
THE LOW 70S TO PRODUCE HEAT INDICES GREATER THAN 100 DEGREES BY
THE EARLY AFTERNOON. HAVE THEREFORE CONTINUED THE HEAT HEADLINES
FOR TODAY.
A SURFACE LOW MOVING EASTWARD ACROSS THE GREAT LAKES WILL DRAG A
COLD FRONT SOUTHWESTWARD TOWARD THE OHIO VALLEY TODAY. IN THE LULL
BEHIND ANY MORNING PRECIPITATION...OUR ATMOSPHERE WILL QUICKLY
DESTABILIZE. THE COMBINATION OF PRE-FRONTAL CONVERGENCE AND A VERY
UNSTABLE AIRMASS WILL TRIGGER THE DEVELOPMENT OF NUMEROUS
THUNDERSTORMS.
THESE INTENSE STORMS WILL BE IN AN ENVIRONMENT OF INCREASING
0 TO 3 KM SHEAR AS THE DAY PROGRESSES...STARTING OFF THE AFTERNOON
AROUND 25 KTS AND ENDING THE DAY AROUND 35 KTS. THE MEAN FLOW FROM
0 TO 3 KM WESTERLIES WILL ALSO INCREASE TO OVER 30 KT THIS
AFTERNOON. THIS WILL LIKELY PRODUCE STORMS THAT WILL ORGANIZE INTO
A QUASI-LINEAR SYSTEM BY LATE THIS AFTERNOON...SURGING EASTWARD
AHEAD OF THE PRE-FRONTAL CONVERGENCE ZONE. AS SHEAR
INCREASES...SOME SUPERCELL CHARACTERISTICS WILL BECOME POSSIBLE
WITH ADDITIONAL LATER THUNDERSTORM DEVELOPMENT BY EARLY THIS
EVENING. THIS SECOND ROUND WILL BE ASSOCIATED WITH AN EMBEDDED
SHORTWAVE. THIS MEANS THAT THERE MAY BE A ONE TWO PUNCH WITH
CONVECTION FOR SOME LOCATIONS IN OUR FORECAST AREA BETWEEN THIS
AFTERNOON AND EVENING TIME FRAME. A SIDE NOTE...THE FIRST ROUND
AND SECOND ROUND MAY NOT HAVE TOO MUCH OF A TIME LAPSE BETWEEN
THEM.
THE MAIN THREAT FROM THE OVERALL CONVECTION TODAY WILL BE
WIDESPREAD DAMAGING WINDS WITH POWER OUTAGES POSSIBLE. HOWEVER
LARGE HAIL COULD OCCUR WITH ANY OF THE STRONGER UPDRAFTS.
ALSO...CANNOT RULE OUT AN ISOLATED TORNADO IF THE RIGHT CONDITIONS
COME TOGETHER LATE TODAY...LL SHEAR...BOUNDARY INTERACTION...ETC.
IF PARTICULAR LOCATIONS DO RECEIVE A ONE TWO PUNCH OF
CONVECTION...OR TRAINING OF STORMS OCCURS...THEN LOCALIZED
FLOODING CAN ALSO BECOME AN ISSUE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CONVECTION WILL SHIFT SOUTHEAST LATE THIS EVENING AND WITH THE
LOSS OF DAYTIME HEATING...WILL GRADUALLY LOSE IT/S INTENSITY.
HOWEVER...STORMS WILL STILL BE INTENSE ENOUGH TO PRODUCE SEVERE
WEATHER AT LEAST THROUGH THE FIRST PART OF THE OVERNIGHT PERIOD.
HAVE THEREFORE KEPT THE MENTION OF SEVERE STORMS IN THE GRIDS
THROUGH 03Z. BY THAT TIME...MOST ACTIVITY WILL HAVE SHIFTED TO OUR
SOUTHEASTERN ZONES. THERE...SOME ONGOING CONVECTIVE ACTIVITY COULD
POSE ADDITIONAL FLOOD ISSUES...SHOULD THUNDERSTORMS BEGIN TO TRAIN
OVER THE SAME LOCATIONS LATE TONIGHT.
ON FRIDAY THERE ARE STILL SOME DIFFERENCES ON HOW THE MODELS HANDLE
THE SHORTWAVE PIVOTING ACROSS THE GREAT LAKES. THE SREF AND NAM
DEVELOP A WEAK CLOSED SURFACE LOW AHEAD OF THE TROUGH AND DIVE IT
SOUTHWARD TOWARD OUR AREA. THIS WOULD PRODUCE A ROUND OF AFTERNOON
CONVECTION FOR THE EASTERN TWO THIRDS OF THE FORECAST AREA. THE
ARW AND NMM BOTH AGREE WITH THIS SOLUTION. HAVE FORECAST 50/50 POPS
FOR MUCH OF THE AREA FOR FRIDAY AFTERNOON TO REFLECT THIS. DID NOT
GO LIKELY ON POPS SINCE THE ECMWF STILL DOES NOT AGREE WITH THIS
SOLUTION.
REGARDLESS OF WHICH MODEL YOU CHOOSE FROM...COLD ADVECTION FINALLY
STABILIZES US FRIDAY NIGHT AS HIGH PRESSURE BEGINS TO BUILD ACROSS
THE OHIO VALLEY. A FEW RESIDUAL SHOWERS AND THUNDERSTORMS COULD
LINGER INTO SATURDAY ACROSS THE EAST AS THE SFC LOW DEPARTS.
SATURDAY THROUGH SATURDAY NIGHT WILL MARK A RETURN TO MORE
SEASONABLE TEMPERATURES AS THE SFC HIGH PRESSURE SETTLES ACROSS
THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY IS PROBABLY THE DAY WITH HIGHEST FORECAST CONFIDENCE AS
SFC HIGH PRESSURE BUILDS OVER THE CWA. TEMPERATURES WILL BE
SEASONABLE WITH FAIRLY LOW HUMIDITY.
THE GFS/NCEP MODELS TAKES A MORE AMPLIFIED TURN BEGINNING
MONDAY...WITH 500 MB HEIGHTS AT ILN RESIDING ON THE LOW END OF NAEFS
SPREAD BY MID WEEK. THIS AFFECTS PCPN FORECASTS MORE THAN
TEMPERATURES HOWEVER OVER THE LOCAL AREA (AS 00Z AND 12Z ECMWF HOLD
A STRONGER SFC RIDGE IN PLACE). TOOK AN ENSEMBLE APPROACH WITH THE
FORECAST...WHICH DID NOT SIGNIFICANTLY CHANGE THE GOING FORECAST.
TUESDAY WILL HAVE THE HIGHEST PCPN CHANCES...SUPPORTED BY
ENSEMBLES...AS WELL AS A SFC BDY/UPPER WAVE THAT MAY SAG DOWN INTO
THE AREA. CANNOT TOTALLY RULE OUT PCPN MONDAY/WEDNESDAY BUT LIMITED
TO 20 POPS. TEMPERATURES WILL RISE SOME AS LOW LEVEL FLOW BECOME
MORE SOUTHERLY...BUT AT THIS TIME LOOK TO REMAIN WITHIN 5 DEGREES OF
NORMAL. HUMIDITY WILL ALSO INCREASE SLIGHTLY...HOLDING UP OVERNIGHT
LOWS.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT ARE CONTINUING TO
WORK THEIR WAY SLOWLY EAST THIS MORNING ACROSS ILLINOIS INTO
NORTHWEST INDIANA. AN OUTFLOW BOUNDARY FROM THESE STORMS IS NOW
EVIDENT ON REGIONAL RADARS STRETCHING FROM NORTHEAST INDIANA DOWN
INTO WEST CENTRAL INDIANA. QUESTIONS REMAIN AS TO WHAT WILL HAPPEN
WITH THIS BOUNDARY AS IT PUSHES EAST INTO OUR AREA THROUGH MID TO
LATE MORNING. THE AIRMASS ACROSS OUR AREA REMAINS UNSTABLE AT
LEAST ALOFT AND WITH SURFACE TEMPS STILL IN THE LOW 80S...NOT SURE
THE DEGREE OF LOW LEVEL INHIBITION PRESENT. SEVERAL OF THE LATEST
HI RES MODELS ARE TRYING TO INDICATE SOME SPOTTY SHOWER
DEVELOPMENT ASSOCIATED WITH THIS BOUNDARY OVER THE NEXT SEVERAL
HOURS. HOWEVER...THIS CHANCE APPEARS FAIRLY LOW AT THIS POINT SO
WILL MAINTAIN A DRY FORECAST THIS MORNING. WE SHOULD DESTABILIZE
FURTHER THROUGH THIS AFTERNOON AND AS BETTER FORCING ARRIVES AHEAD
OF THE APPROACHING COLD FRONT...EXPECT SHOWERS AND THUNDERSTORMS
TO DEVELOP THROUGH MID AFTERNOON. SHOWER ACTIVITY SHOULD MOVE OFF
TO THE SOUTHEAST THROUGH LATE AFTERNOON BUT WILL LIKELY SEE A
SECONDARY AREA OF CONVECTION DEVELOP THROUGH EARLY EVENING AS MID
LEVEL TROUGH AXIS APPROACHES. AHEAD OF THE FRONT...EXPECT SOME
GUSTY SOUTHWEST WINDS TO DEVELOP LATER THIS MORNING INTO THIS
AFTERNOON. IN ADDITION...STRONGER WIND GUSTS WILL BE POSSIBLE WITH
CONVECTIVE STORMS. TSTM ACTIVITY SHOULD TAPER OFF LATER THIS
EVENING AND IF WE ARE ABLE TO SCATTER OUT....WE COULD SEE SOME
AREAS OF BR DEVELOP LATER TONIGHT.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE THROUGH FRIDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
OHZ026-034-035-042>046-051>056-060-062>065-070>074-
078>082-088.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR OHZ061-
077.
KY...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
KYZ089>100.
IN...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
INZ050-058-059-066-073>075-080.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...SNYDER
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
447 AM EDT THU JUL 26 2012
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL GIVE WAY TO STRONG TO SEVERE
THUNDERSTORMS TODAY AS A COLD FRONT MOVES SOUTHWEST TOWARD THE
OHIO VALLEY. THE FRONT WILL PUSH THROUGH THE AREA TONIGHT AND A
LOW PRESSURE SYSTEM WILL CROSS OUR AREA ON FRIDAY...BRINGING
ADDITIONAL SHOWERS AND THUNDERSTORMS TO THE REGION. HIGH PRESSURE
WILL THEN BRING MORE SEASONABLE TEMPERATURES AND DRIER CONDITIONS
FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STEADY WARM ADVECTION UNDER SOUTHWEST FLOW WILL CONTINUE THROUGH
SUNRISE. OUTFLOW FROM CONVECTION TO OUR NORTHWEST IS TRIGGERING
SHOWERS AND THUNDERSTORMS ACROSS PARTS OF ILLINOIS AND INDIANA.
SOME OF THESE STORMS WILL HOLD TOGETHER AND MAKE IT TO OUR WESTERN
ZONES JUST AFTER SUNRISE THIS MORNING. AS THIS ACTIVITY OUTRUNS
THE FRONTAL FORCING...AND WE ENTER THE DIURNAL MINIMUM FOR
CONVECTION...ANY REMAINING SHOWERS/THUNDERSTORMS WILL DIMINISH BY
MID MORNING. HAVE THEREFORE FORECAST A LULL IN ANY POPS DURING
THE MID MORNING UNTIL EARLY AFTERNOON. THIS FORECAST TO START OFF
THE DAY BEST RESEMBLES THE HRRR AND SREF. HAVE AVOIDED USING THE 00Z
ARW AND SPC WRF FOR THIS PACKAGE...AS THEY APPEAR TO BRING AN
INITIATION OF TOO MUCH CONVECTION TOO FAR EAST...TOO EARLY IN THE
DAY. THIS IS LIKELY DUE TO THE HANDLING OF THE AFOREMENTIONED
OUTFLOW BOUNDARY INTERACTING WITH OUR UNSTABLE AIRMASS...AND NOT
THE DEVELOPMENT OF THE MORE INTENSE...SYNOPTICALLY FORCED
CONVECTION THAT WILL OCCUR LATE THIS AFTERNOON.
WITH ONGOING WARM ADVECTION AND INCREASING SOUTHERLY FLOW TO START
OFF THE DAY...THE BOUNDARY LAYER WILL BE WELL MIXED. TEMPERATURES
OF 20 TO 21 C AT 850 HPA...UNDER PARTLY CLOUDY SKIES...WILL BRING
SURFACE TEMPERATURES QUICKLY INTO THE LOW 90S BY THE EARLY
AFTERNOON. THESE WARM TEMPERATURES WILL COMBINE WITH DEWPOINTS IN
THE LOW 70S TO PRODUCE HEAT INDICES GREATER THAN 100 DEGREES BY
THE EARLY AFTERNOON. HAVE THEREFORE CONTINUED THE HEAT HEADLINES
FOR TODAY.
A SURFACE LOW MOVING EASTWARD ACROSS THE GREAT LAKES WILL DRAG A
COLD FRONT SOUTHWESTWARD TOWARD THE OHIO VALLEY TODAY. IN THE LULL
BEHIND ANY MORNING PRECIPITATION...OUR ATMOSPHERE WILL QUICKLY
DESTABILIZE. THE COMBINATION OF PRE-FRONTAL CONVERGENCE AND A VERY
UNSTABLE AIRMASS WILL TRIGGER THE DEVELOPMENT OF NUMEROUS
THUNDERSTORMS.
THESE INTENSE STORMS WILL BE IN AN ENVIRONMENT OF INCREASING
0 TO 3 KM SHEAR AS THE DAY PROGRESSES...STARTING OFF THE AFTERNOON
AROUND 25 KTS AND ENDING THE DAY AROUND 35 KTS. THE MEAN FLOW FROM
0 TO 3 KM WESTERLIES WILL ALSO INCREASE TO OVER 30 KT THIS
AFTERNOON. THIS WILL LIKELY PRODUCE STORMS THAT WILL ORGANIZE INTO
A QUASI-LINEAR SYSTEM BY LATE THIS AFTERNOON...SURGING EASTWARD
AHEAD OF THE PRE-FRONTAL CONVERGENCE ZONE. AS SHEAR
INCREASES...SOME SUPERCELL CHARACTERISTICS WILL BECOME POSSIBLE
WITH ADDITIONAL LATER THUNDERSTORM DEVELOPMENT BY EARLY THIS
EVENING. THIS SECOND ROUND WILL BE ASSOCIATED WITH AN EMBEDDED
SHORTWAVE. THIS MEANS THAT THERE MAY BE A ONE TWO PUNCH WITH
CONVECTION FOR SOME LOCATIONS IN OUR FORECAST AREA BETWEEN THIS
AFTERNOON AND EVENING TIME FRAME. A SIDE NOTE...THE FIRST ROUND
AND SECOND ROUND MAY NOT HAVE TOO MUCH OF A TIME LAPSE BETWEEN
THEM.
THE MAIN THREAT FROM THE OVERALL CONVECTION TODAY WILL BE
WIDESPREAD DAMAGING WINDS WITH POWER OUTAGES POSSIBLE. HOWEVER
LARGE HAIL COULD OCCUR WITH ANY OF THE STRONGER UPDRAFTS.
ALSO...CANNOT RULE OUT AN ISOLATED TORNADO IF THE RIGHT CONDITIONS
COME TOGETHER LATE TODAY...LL SHEAR...BOUNDARY INTERACTION...ETC.
IF PARTICULAR LOCATIONS DO RECEIVE A ONE TWO PUNCH OF
CONVECTION...OR TRAINING OF STORMS OCCURS...THEN LOCALIZED
FLOODING CAN ALSO BECOME AN ISSUE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
CONVECTION WILL SHIFT SOUTHEAST LATE THIS EVENING AND WITH THE
LOSS OF DAYTIME HEATING...WILL GRADUALLY LOSE IT/S INTENSITY.
HOWEVER...STORMS WILL STILL BE INTENSE ENOUGH TO PRODUCE SEVERE
WEATHER AT LEAST THROUGH THE FIRST PART OF THE OVERNIGHT PERIOD.
HAVE THEREFORE KEPT THE MENTION OF SEVERE STORMS IN THE GRIDS
THROUGH 03Z. BY THAT TIME...MOST ACTIVITY WILL HAVE SHIFTED TO OUR
SOUTHEASTERN ZONES. THERE...SOME ONGOING CONVECTIVE ACTIVITY COULD
POSE ADDITIONAL FLOOD ISSUES...SHOULD THUNDERSTORMS BEGIN TO TRAIN
OVER THE SAME LOCATIONS LATE TONIGHT.
ON FRIDAY THERE ARE STILL SOME DIFFERENCES ON HOW THE MODELS HANDLE
THE SHORTWAVE PIVOTING ACROSS THE GREAT LAKES. THE SREF AND NAM
DEVELOP A WEAK CLOSED SURFACE LOW AHEAD OF THE TROUGH AND DIVE IT
SOUTHWARD TOWARD OUR AREA. THIS WOULD PRODUCE A ROUND OF AFTERNOON
CONVECTION FOR THE EASTERN TWO THIRDS OF THE FORECAST AREA. THE
ARW AND NMM BOTH AGREE WITH THIS SOLUTION. HAVE FORECAST 50/50 POPS
FOR MUCH OF THE AREA FOR FRIDAY AFTERNOON TO REFLECT THIS. DID NOT
GO LIKELY ON POPS SINCE THE ECMWF STILL DOES NOT AGREE WITH THIS
SOLUTION.
REGARDLESS OF WHICH MODEL YOU CHOOSE FROM...COLD ADVECTION FINALLY
STABILIZES US FRIDAY NIGHT AS HIGH PRESSURE BEGINS TO BUILD ACROSS
THE OHIO VALLEY. A FEW RESIDUAL SHOWERS AND THUNDERSTORMS COULD
LINGER INTO SATURDAY ACROSS THE EAST AS THE SFC LOW DEPARTS.
SATURDAY THROUGH SATURDAY NIGHT WILL MARK A RETURN TO MORE
SEASONABLE TEMPERATURES AS THE SFC HIGH PRESSURE SETTLES ACROSS
THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SUNDAY IS PROBABLY THE DAY WITH HIGHEST FORECAST CONFIDENCE AS
SFC HIGH PRESSURE BUILDS OVER THE CWA. TEMPERATURES WILL BE
SEASONABLE WITH FAIRLY LOW HUMIDITY.
THE GFS/NCEP MODELS TAKES A MORE AMPLIFIED TURN BEGINNING
MONDAY...WITH 500 MB HEIGHTS AT ILN RESIDING ON THE LOW END OF NAEFS
SPREAD BY MID WEEK. THIS AFFECTS PCPN FORECASTS MORE THAN
TEMPERATURES HOWEVER OVER THE LOCAL AREA (AS 00Z AND 12Z ECMWF HOLD
A STRONGER SFC RIDGE IN PLACE). TOOK AN ENSEMBLE APPROACH WITH THE
FORECAST...WHICH DID NOT SIGNIFICANTLY CHANGE THE GOING FORECAST.
TUESDAY WILL HAVE THE HIGHEST PCPN CHANCES...SUPPORTED BY
ENSEMBLES...AS WELL AS A SFC BDY/UPPER WAVE THAT MAY SAG DOWN INTO
THE AREA. CANNOT TOTALLY RULE OUT PCPN MONDAY/WEDNESDAY BUT LIMITED
TO 20 POPS. TEMPERATURES WILL RISE SOME AS LOW LEVEL FLOW BECOME
MORE SOUTHERLY...BUT AT THIS TIME LOOK TO REMAIN WITHIN 5 DEGREES OF
NORMAL. HUMIDITY WILL ALSO INCREASE SLIGHTLY...HOLDING UP OVERNIGHT
LOWS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
MAINLY CLEAR SKIES ACROSS THE AREA THIS MORNING WITH THE REGION
NOW WELL INTO THE WARM SECTOR. AS THE COLD FRONT OFF TO OUR
NORTHWEST SAGS SLOWLY SOUTHEAST THROUGH THIS AFTERNOON...WE WILL
SEE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. SEVERAL OF
THE LATEST MODEL RUNS ARE SUGGESTING AN OUTFLOW BOUNDARY FROM
CONVECTION OFF TO OUR NORTHWEST WILL MOVE INTO OUR AREA LATER
THIS MORNING INTO EARLY AFTERNOON. IF THIS OCCURS...IT WILL LIKELY
SERVE AS A FOCUS FOR THE FIRST ROUND OF CONVECTION TO AFFECT OUR
TAF SITES AS THE AIRMASS IS ALREADY VERY UNSTABLE EARLY THIS
MORNING. HOWEVER...GIVEN THE RIDGE IN PLACE OVER OUR AREA AT THIS
TIME...AM AFRAID THE MODELS MAY BE A LITTLE FAST BRINGING THIS INTO
OUR AREA. ON THE OTHER HAND...IT IS TOUGH TO DISCOUNT THIS
SOMEWHAT FASTER SOLUTION GIVEN THE MODEL TRENDS...SO WILL OPEN UP
A SLIGHTLY BIGGER WINDOW ON THE CONVECTION CHANCES THIS AFTERNOON.
WITH THE VERY UNSTABLE AIRMASS EXPECTED THROUGH THIS AFTERNOON...STRONG
DOWN BURST WINDS WILL BE POSSIBLE WITH THE STORMS...ESPECIALLY
THOSE THAT OCCUR IN THE AFTERNOON HOURS. THIS INITIAL ROUND OF
STORMS WILL LIKELY MOVE OFF TO THE SOUTH BY LATE AFTERNOON. A
SECONDARY AREA OF SHOWERS AND THUNDERSTORMS WILL THEN BE POSSIBLE
HEADING INTO THIS EVENING AS A MID LEVEL SHORT WAVE MOVES IN
QUICKLY FROM THE WEST. EXPECT THE BEST CHANCE FOR THIS
REDEVELOPMENT TO BE AT THE SOUTHERN TAF SITES.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE THROUGH FRIDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
OHZ026-034-035-042>046-051>056-060-062>065-070>074-
078>082-088.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR OHZ061-
077.
KY...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
KYZ089>100.
IN...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
INZ050-058-059-066-073>075-080.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...SNYDER
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
213 AM EDT THU JUL 26 2012
.SYNOPSIS...
HIGH PRESSURE OFF THE SE COAST WILL ALLOW A WARM FRONT OVER THE
OHIO VALLEY TO SURGE INTO THE REGION LATER TONIGHT AND THURSDAY.
A SLOW MOVING COLD FRONT WILL SLIDE ACROSS THURSDAY INTO FRIDAY
BRINGING AN ACTIVE PERIOD OF WEATHER THROUGH THE END OF THE WEEK
WITH STRONG TO SEVERE THUNDERSTORMS POSSIBLE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HIGH PRESSURE HAS SLIPPED OFF TO OUR SE. A WARM FRONT OVER OHIO
WILL CONTINUE TO MARCH NE THRU THE REGION SETTING THE STAGE FOR
ANOTHER VERY WARM/HUMID DAY THURSDAY.
BIGGEST QUESTION FOR THE VERY NEAR TERM IS IF WE WILL SEE A LINE
OF SEVERE STORMS RACE ACROSS THE FCST AREA AFTER MIDNIGHT.
REGIONAL RADAR MOSAIC SHOWS AN MCS FORMING RAPIDLY OVER MICHIGAN.
HIGH RES HRRR AND COSPA NOW BACK OFF THE IDEA OF A BOW ECHO
LOOKING FEATURE SWEEPING THRU AND BRING MORE DISORGANIZED STORMS
INTO THE FCST AREA LATER AT NIGHT...TWD DAWN. THIS ALSO FITS WITH
THE NEW NAM WHICH SUGGESTS THE BEST CONVECTION STAYS NORTH OF THE
BORDER THRU 12Z FOR THE MOST PART.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
SPC HAS A MDT RISK OF SVR TSRA VERY LATE TONIGHT AND THURSDAY.
CLUSTERS OF DISCRETE...SUPERCELL STRUCTURES OVER THE NW MTNS DURING
THE PREDAWN HOURS THURSDAY...MAY EVOLVE INTO A LARGER MCS/MCC ACROSS
CENTRAL PENN WITH SWATHS OF WIND DAMAGE /AND FREQUENT LIGHTNING/
BEING THE PRIMARY THREAT ACROSS CENTRAL PENN AND THE SUSQ VALLEY
DURING THE MID MORNING HOURS. 09Z SREF AND 12 GEFS BOTH HIGHLIGHT
THE EXTREMELY STRONG FORCING TRIGGERING THIS INITIAL ROUND OF
TSRA...AS A +3-5 ST DEVIATION WESTERLY 850 MB JET PUSHES ACROSS PENN
AND NEW YORK BETWEEN 08Z AND 14Z THURSDAY.
IN ADDITION...THE SREF/S 850 MB MOISTURE FLUX IS SO TO SAY..OFF THE
CHARTS DURING THE AFOREMENTIONED PERIOD OF INTEREST THURSDAY
MORNING...6 OR MORE STANDARD DEVIATIONS ABOVE NORMAL.
A BRIEF...FEW HOUR PERIOD OF MINIMAL CONVECTIVE ACTIVITY MAY OCCUR
BETWEEN 14-17Z AS COMPENSATING SUBSIDENCE OCCURS IN THE WAKE OF THE
MCS...BEFORE AREAS OF POTENTIALLY SEVERE TSRA FIRE DURING THE MID TO
LATE AFTERNOON HOURS.
ANOMALOUSLY HIGH 850 MB TEMPS OF 20-22C WILL COMBINE WITH A GUSTY
WSW SFC WIND AND ABUNDANT LATE MORNING - MID AFTERNOON SUN TO PUSH
TEMPS TO NEAR RECORD HIGHS WITH HEAT INDICES IN THE 90S ACROSS THE
MTNS...TO BETWEEN 100-104F IN THE SOUTHERN VALLEYS AND THROUGHOUT
MUCH OF THE LOWER TO MID SUSQ VALLEY. RECORDS FOR 7/26 ARE 100F IN
MDT...AND 98F IN KIPT.
A HEAT ADVISORY HAS BEEN POSTED FOR 16Z THU-00Z FRIDAY FOR NEARLY
THE SE HALF OF THE CWA.
THE SREF MEAN CAPES FOR THE AFTN RISE INTO THE 2000-2500J/KG RANGE -
ESP OVER THE NRN HALF OF THE AREA. WINDS WILL BE UNIDIRECTIONAL AT
THAT POINT AND 0-6KM BULK SHEAR AROUND 40KTS. THE SFC LOW PASSING
THROUGH NY STATE AND INTO NEW ENGLAND WILL TRY TO PUSH A SLIGHTLY
COOLER AIR MASS IN FROM THE NORTH. THIS WILL CREATE A GREAT FOCUS
FOR CONVECTION AND LITTLE CINH WILL ALLOW FOR SCT/NMRS TSRA IN THE
AFTN AND INTO THE EARLY PART OF THE NIGHT. HOWEVER...LACK OF HEATING
WILL MOST LIKELY DIMINISH/KILL THE DEEP CONVECTION WITH ONLY WEAK
CONVERGENCE PRESENT ALONG THE BOUNDARY...AND POOR INFLUX OF
ADDITIONAL MSTR FROM THE GULF.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SVR WX THREAT MAY PERSIST INTO THURS NIGHT BEFORE TRENDING WEAKER
TOWARD CLIMATOLOGICAL CONVECTIVE MINIMUM/EARLY FRI MORNING. THE
STRONGEST WLY 850MB WINDS AND LLVL MSTR WILL SHIFT EWD AND EXIT
SERN PA BTWN 12-15Z...ALONG WITH THE LEADING FRONTAL BOUNDARY.
OVERNIGHT MINS SHOULD BE VERY MILD AND LKLY STAY AOA 75F IN THE
HARRISBURG/YORK/LANCASTER METRO AREA.
UPPER TROF AXIS IS EXPECTED TO SHIFT EWD ACRS THE OH VLY INTO THE
CENTRAL APPALACHIANS ON FRIDAY. DESPITE WEAKER INSTABILITY/LOWER
DEWPOINTS...THERE IS A RELATIVELY LOW THREAT FOR SCT STG TO
PERHAPS SVR STORMS TO DEVELOP IN ADVANCE OF THE MID-UPPER TROF.
MODEST DEEP LYR SHEAR SUGGESTS SOME LOOSELY ORGANIZED CLUSTERS MAY
FORM...MAINLY OVR THE SRN 1/2 OF THE AREA WHERE SPC HAS DRAWN IN A
D3 CATEGORICAL SEE TEXT.
THE PERIOD FROM SAT-WED WILL FEATURE A NEARLY STAGNANT LG SCALE
PATTERN OVR THE LOWER 48...WITH TROUGHING OVER THE ERN U.S.
EXTENDING SWD FM HUDSON BAY UPPER LOW. THE MODELS AND ENSEMBLES
SHOW GOOD AGREEMENT ON THIS SYNOPTIC PATTERN. TEMPS SHOULD AVG
NEAR NORMAL INTO THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
WIDESPREAD VFR CONDS ACROSS CENTRAL PA AT 06Z. HOWEVER...TSRA
ASSOCIATED WITH AN APPROACHING WARM FRONT COULD POTENTIALLY AFFECT
PORTIONS OF THE AREA BTWN 09Z-13Z. UNCERTAINTY TOO HIGH TO MENTION
EXPLICITLY IN FCST AT THIS TIME. HOWEVER...UPSTREAM RADAR LOOP AND
LATEST MDL DATA SUGGEST BFD IS THE MOST LIKELY AIRFIELD TO
EXPERIENCE A GUSTY TSRA WITH REDUCED VSBYS THIS MORNING. STRONG SW
WINDS ALOFT...COMBINED WITH MUCH LIGHTER SFC WINDS...WILL LIKELY
RESULT IN A PERIOD OF LLWS AT MOST LOCATIONS EARLY THIS MORNING.
AS WARM FRONT PUSHES NORTH OF THE AREA BTWN 13Z-15Z...EXPECT
AN INCREASINGLY GUSTY SW SFC WIND AND DIMINISHING LLWS. BUFKIT
SOUNDINGS SUPPORT FREQUENT GUSTS LATER TODAY BTWN 20-25KTS.
BIG CONCERN THIS AFTN AND EVENING WILL BE THE POSSIBILITY OF
STRONG THUNDERSTORMS DEVELOPING AHEAD OF COLD FRONT PUSHING SE
ACROSS THE GRT LKS. ALTHOUGH VFR CONDS SHOULD PREDOMINATE OVER
THE AREA THIS AFTN...THERE IS A GOOD CHC FOR A BRIEF VIS/CIG
REDUCTION ACCOMPANYING A GUSTY TSRA. MOST LIKELY TIME FRAME FOR
TSRA WILL BE 18Z-00Z AT BFD AND BTWN 20Z-02Z AT IPT/UNV/AOO/JST.
MDT AND LNS COULD EXPERIENCE AN EVENING TSRA...ALTHOUGH CHANCES
NOT AS GREAT THERE.
OUTLOOK...
FRI...AM LOW CIGS POSSIBLE W MTNS. ISOLD PM TSRA IMPACTS POSSIBLE.
SAT...AM FOG POSSIBLE. ISOLD PM TSRA IMPACTS POSSIBLE.
SUN...AM FOG POSSIBLE.
MON...ISOLD PM TSRA IMPACTS POSSIBLE.
&&
.EQUIPMENT...
STATE COLLEGE RADAR HAS BEEN RETURNED TO SERVICE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
PAZ026>028-034>036-049>052-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
443 PM EDT THU JUL 26 2012
.SYNOPSIS...
MOISTURE WILL BE ON THE INCREASE FRIDAY OUT AHEAD OF AN APPROACHING
WEAK COOL FRONT. THIS FRONT WILL SETTLE INTO AND MOVE THROUGH THE
REGION OVER THE WEEKEND. SURFACE HIGH PRESSURE WILL BUILD BACK OVER
THE AREA LATER SUNDAY AND REMAIN THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 440 PM...RADAR STILL PPINE THIS AFTERNOON. HOWEVER...THERE
HAVE BEEN A FEW ENHANCED ECHOES ACROSS THE MTNS THAT DID NOT DEVELOP
FURTHER. LATEST GUIDANCE STILL SUGGESTS ISOLATED CONVECTION POSSIBLE
ACROSS THE MTNS FOR LATE AFTERNOON AND EARLY EVENING WHERE CAP
SHOULD HAVE ERODED. WILL LEAVE THE CURRENT POP TRENDS IN PLACE.
UPDATES BASICALLY FOR CURRENT CONDITIONS ONLY.
AT 215 PM...CURRENT TEMP TREND NOW BEGINNING TO LAG SOMEWHAT
SO HAVE ADJUSTED TEMP TREND. MAY JUST MARGINALLY HIT THE HEAT
ADVISORY CRITERIA ACROSS THE SOUTHERN PIEDMONT AREAS LATE THIS
AFTERNOON AS DEWPOINTS MIX OUT A TAD. HOWEVER...WILL LEAVE THE
CURRENT HEAT ADVISORY IN PLACE. STILL EXPECT THAT ANY DEEP
CONVECTION THIS AFTERNOON WILL BE WIDELY SCATTERED OVER THE HIGH
TERRAIN OF WESTERN NC AS LFC`S DROP TO AROUND 5K FT. A CAPPING
INVERSION IN THE 5K-8K RANGE OUTSIDE THE MOUNTAINS SHOULD PRECLUDE
ANY THREAT FOR DEEP CONVECTION THERE. THE EXCEPTION OUTSIDE THE
MOUNTAINS IS OVER PARTS OF NE GA AND THE WESTERN UPSTATE WHERE
WIDELY SCT THUNDERSTORMS MAY OCCUR IN THE 00Z-03Z TIMEFRAME AS A
WEAK VORT MAX MOVES NE OUT OF GA. 12Z NAM/GFS AND RAP ALL SHOWING
SOME CONVECTIVE RESPONSE IN THAT AREA.
AFTER MIDNIGHT...IT LOOKS LIKE LIKE IT WILL BE QUIET WITH MOSTLY
CLEAR CONDITIONS. IT WILL BE AN UNSEASONABLY WARM NIGHT UNDER THE
DEPARTING UPPER RIDGE. LOWS WILL BE A GOOD 5 DEGREES ABOVE AVERAGE.
ON FRI...CONDITIONS FOR DEEP CONVECTION WILL BECOME MORE FAVORABLE
THROUGHOUT THE DAY AS A SHORT WAVE MOVES THROUGH THE GREAT LAKES WHICH
LOWERS HEIGHTS OVER THE EASTERN U.S. AT THE SAME TIME...A WEAK
FRONTAL BOUNDARY WILL APPROACH FROM THE NW. WIND FIELDS WILL ALSO
IMPROVE WITH SFC-6KM BULK SHEAR INCREASING TO AROUND 20KTS FRI
AFTERNOON. HENCE...EXPECT SCT TO NUMEROUS THUNDERSTORMS TO DEVELOP
OVER THE NC MOUNTAINS DURING THE EARLY AFTERNOON WITH AT LEAST
SCATTERED STORMS PROGRESSING SE INTO THE PIEDMONT AREAS IN THE MID
TO LATE AFTERNOON HOURS. SEVERE STORMS ARE POSSIBLE PER THE LATEST
SPC DAY 2 OUTLOOK WHICH HAS MOST OF THE AREA IN A SLIGHT RISK. FRI
WILL BE ANOTHER HOT DAY...ESPECIALLY OUTSIDE THE MOUNTAINS WHERE MID
TO UPPER 90S ARE EXPECTED. WITH DEWPOINTS IN THE LOWER 70S OUTSIDE
THE MOUNTAINS...HEAT ADVISORY CONDITIONS (105-110) SHOULD BE MET OVER THE
SOUTHERN PIEDMONT AREAS ONCE AGAIN. WILL GO AHEAD AND ISSUE A HEAT
ADVISORY FOR THAT AREA FOR FRI AFTERNOON.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AT 215 PM EDT THURSDAY...AN UPPER TROUGH AXIS WILL REMAIN OVER THE
EASTERN USA FROM FRIDAY NIGHT THROUGH SUNDAY. A VIGOROUS SHORTWAVE
WILL DIVE INTO THE BASE OF THIS TROUGH ON FRIDAY NIGHT...CROSSING
THE SOUTHERN APPALACHIANS ON SATURDAY. A WEAKER SHORTWAVE WILL
FOLLOW...CROSSING THE MOUNTAINS ON SUNDAY. THE REMAINS OF A COLD
FRONT WILL MOVES SOUTHEAST ACROSS THE PIEDMONT FRIDAY NIGHT...WHILE
ANOTHER COLD FRONT...WHILE A NEW COLD FRONT AND ITS MOISTURE BAND
CROSS THE MOUNTAINS FROM THE NW. THIS SECOND FRONT REACHES THE
PIEDMONT BY SATURDAY AFTERNOON. DRYING OCCURS BEHIND THE SECOND
FRONT SATURDAY NIGHT AS IT DRIFTS INTO THE PIEDMONT...HOWEVER THE
GFS KEEP SOME MOISTURE BANKED UP AGAINST THE BLUE RIDGE INTO SUNDAY.
CHANCE POPS WILL BE CARRIED WITH THE TWO FRONTS CROSSING THE
AREA...WITH MAXIMUM POPS DURING DAYTIME HEATING. CAPE IS EXPECTED TO
BE AT A MAXIMUM ALONG AND AHEAD OF THE PRIMARY BOUNDARY SATURDAY
AFTERNOON. NAM SOUNDINGS LOOK MORE FAVORABLE FOR SEVERE WEATHER THAN
GFS SOUNDINGS. A DECREASE IN POPS WILL BE PERMITTED BEHIND THE FRONT
SATURDAY NIGHT AND SUNDAY...BUT SMALL POPS WILL LINGER ALONG THE
BLUE RIDGE PER THE GFS SOLUTION... AS THE SECOND AND WEAKER
SHORTWAVE ARRIVES. LIFT AND MOISTURE WITH THE SECOND SHORTWAVE ARE
DEPICTED AS BEING MORE SHALLOW THAN WITH THE FIRST. TEMPERATURES
WILL BE ABOVE NORMAL...BUT WITH A SLIGHT DECREASE ON SUNDAY IN THE
WAKE OF THE SECOND FRONT. THE HEAT INDEX WILL REMAIN BELOW 100
DEGREE IN THE PIEDMONT SATURDAY...AND WILL BE EVEN LOWER ON SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 140 PM THURSDAY...MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT
WITH RESPECT TO THE GENERAL PATTERN TO START OFF THE PERIOD...THE
CWFA ORIENTED NEAR THE BASE OF EASTERN CONUS TROUGH. THE WEAK SFC
FRONT WHICH IS PROGGED TO SLIP INTO THE CAROLINAS THIS WEEKEND IS
FCST TO STEADILY WEAKEN AS IT STALLS ACRS THE COASTAL PLAIN. ON A
REGIONAL SCALE...GREATEST DIURNAL TSTM CVRG SHOULD WIND UP ORIENTED
ALONG AND COASTWARD OF SFC FRONT...BUT APPROACHING IMPULSE WITHIN
THE WNW FLOW SHOULD BE ABLE TO TRIGGER AT LEAST SCATTERED ACTIVITY
ACRS THE WESTERN CAROLINAS ON TUESDAY. MAX TEMPERATURES FOR THE NEW
DAY 4 AND 5 WILL BE PRETTY TYPICAL FOR LATE JULY...WITHIN A FEW DEG
F OF CLIMO. DURING THE LATTER HALF OF THE PERIOD...AFOREMENTIONED SFC
FRONT BECOMES INCREASINGLY FRONTOLYTIC AND THE MEAN PATTERN...
EASTERN CONUS TROUGH...CHANGES LITTLE. GIVEN THE AMPLITUDE OF THE
PATTERN AND THE POTENTIAL FOR ADDITIONAL CHUNKS OF ENERGY TO ROTATE
THRU...FEEL THAT SOLID MAINLY DIURNAL TSTM CHANCES WILL EXIST EACH
DAY WITH TEMPERATURES STILL VERY CLOSE TO CLIMO.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
AT KCLT...CONVECTIVE THREAT APPEARS NIL THIS AFTERNOON AS A CAPPING
INVERSION IS EXPECTED TO HOLD FIRM. EXPECT MCLR SKIES THROUGH
TONIGHT WITH SCT CU DEVELOPING LATE FRI MORNING. WINDS WILL REMAIN
GENERALLY LIGHT SW...EXCEPT FOR A FEW GUSTS TO AROUND 12KT LATE THIS
AFTERNOON.
ELSEWHERE...SIMILAR CONDITIONS TO KCLT EXCEPT FOR SOME LIGHT FOG AT
KAVL EARLY FRI. SLIGHT CHC POPS SHOULD REMAIN LIMITED TO THE MTNS THIS
AFTN.
OUTLOOK...CHANCE FOR THUDNERSTORMS WILL INCREASE FRI AS A SHORTWAVE
AND ASSOC WEAK COLD FRONT MOVE IN FROM THE NW. ANOTHER CHANCE FOR
THUNDERSTORMS WILL OCCUR SAT AFTERNOON AS ANOTHER COLD FRONT MOVES
THROUGH. THEN EXPECT A DAILY CHANCE FOR AFTERNOON CONVECTION INTO
THE MIDDLE OF NEXT WEEK...FIRST OVER SOUTHERN AREAS ON SUNDAY THEN
AREA WIDE AS 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.
HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR GAZ029.
NC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ071-072-082.
HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR NCZ071-072-082.
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ009-011>014-
019.
HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR SCZ009-011>014-
019.
&&
$$
SYNOPSIS...CSH
NEAR TERM...LG/RWH
SHORT TERM...JAT
LONG TERM...CSH
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
218 PM EDT THU JUL 26 2012
.SYNOPSIS...
MOISTURE WILL BE ON THE INCREASE FRIDAY OUT AHEAD OF AN APPROACHING
WEAK COOL FRONT. THIS FRONT WILL SETTLE INTO AND MOVE THROUGH THE
REGION OVER THE WEEKEND. SURFACE HIGH PRESSURE WILL BUILD BACK OVER
THE AREA LATER SUNDAY AND REMAIN THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AT 215 PM...CURRENT TEMP/DEWPOINT TREND NOW BEGINNING TO LAG
SOMEWHAT SO HAVE ADJUSTED TEMP TREND. MAY JUST MARGINALLY HIT THE
HEAT ADVISORY CRITERIA ACROSS THE SOUTHERN PIEDMONT AREAS LATE THIS
AFTERNOON AS DEWPOINTS MIX OUT A TAD. HOWEVER...WILL LEAVE THE
CURRENT HEAT ADVISORY IN PLACE. STILL EXPECT THAT ANY DEEP
CONVECTION THIS AFTERNOON WILL BE WIDELY SCATTERED OVER THE HIGH
TERRAIN OF WESTERN NC AS LFC`S DROP TO AROUND 5K FT. A CAPPING
INVERSION IN THE 5K-8K RANGE OUTSIDE THE MOUNTAINS SHOULD PRECLUDE
ANY THREAT FOR DEEP CONVECTION THERE. THE EXCEPTION OUTSIDE THE
MOUTNAINS IS OVER PARTS OF NE GA AND THE WESTERN UPSTATE WHERE
WIDELY SCT THUNDERSTORMS MAY OCCUR IN THE 00Z-03Z TIMEFRAME AS A
WEAK VORT MAX MOVES NE OUT OF GA. 12Z NAM/GFS AND RAP ALL SHOWING
SOME CONVECTIVE RESPONSE IN THAT AREA.
AFTER MIDNIGHT...IT LOOKS LIKE LIKE IT WILL BE A QUIET WITH MOSTLY
CLEAR CONDITIONS. IT WILL BE AN UNSEASONABLY WARM NIGHT UNDER THE
DEPARTING UPPER RIDGE. LOWS WILL BE A GOOD 5 DEGREES ABOVE AVERAGE.
ON FRI...CONDITIONS FOR DEEP CONVECTION WILL BECOME MORE FAVORABLE
THROUGHOUT THE DAY AS A SHORT WAVE MOVES THROUGH THE GREAT LAKES WHICH
LOWERS HEIGHTS OVER THE EASTERN U.S. AT THE SAME TIME...A WEAK
FRONTAL BOUNDARY WILL APPROACH FROM THE NW. WIND FIELDS WILL ALSO
IMPROVE WITH SFC-6KM BULK SHEAR INCREASING TO AROUND 20KTS FRI
AFTERNOON. HENCE...EXPECT SCT TO NUMEROUS THUNDERSTORMS TO DEVELOP
OVER THE NC MOUNTAINS DURING THE EARLY AFTERNOON WITH AT LEAST
SCATTERED STORMS PROGRESSING SE INTO THE PIEDMONT AREAS IN THE MID
TO LATE AFTERNOON HOURS. SEVERE STORMS ARE POSSIBLE PER THE LATEST
SPC DAY 2 OUTLOOK WHICH HAS MOST OF THE AREA IN A SLIGHT RISK. FRI
WILL BE ANOTHER HOT DAY...ESPECIALLY OUTSIDE THE MOUNTAINS WHERE MID
TO UPPER 90S ARE EXPECTED. WITH DEWPOINTS IN THE LOWER 70S OUTSIDE
THE MOUNTAINS...HEAT ADVISORY CONDITIONS (105-110) SHOULD BE MET OVER THE
SOUTHERN PIEDMONT AREAS ONCE AGAIN. WILL GO AHEAD AND ISSUE A HEAT
ADVISORY FOR THAT AREA FOR FRI AFTERNOON.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AT 215 PM EDT THURSDAY...AN UPPER TROUGH AXIS WILL REMAIN OVER THE
EASTERN USA FROM FRIDAY NIGHT THROUGH SUNDAY. A VIGOROUS SHORTWAVE
WILL DIVE INTO THE BASE OF THIS TROUGH ON FRIDAY NIGHT...CROSSING
THE SOUTHERN APPALACHIANS ON SATURDAY. A WEAKER SHORTWAVE WILL
FOLLOW...CROSSING THE MOUNTAINS ON SUNDAY. THE REMAINS OF A COLD
FRONT WILL MOVES SOUTHEAST ACROSS THE PIEDMONT FRIDAY NIGHT...WHILE
ANOTHER COLD FRONT...WHILE A NEW COLD FRONT AND ITS MOISTURE BAND
CROSS THE MOUNTAINS FROM THE NW. THIS SECOND FRONT REACHES THE
PIEDMONT BY SATURDAY AFTERNOON. DRYING OCCURS BEHIND THE SECOND
FRONT SATURDAY NIGHT AS IT DRIFTS INTO THE PIEDMONT...HOWEVER THE
GFS KEEP SOME MOISTURE BANKED UP AGAINST THE BLUE RIDGE INTO SUNDAY.
CHANCE POPS WILL BE CARRIED WITH THE TWO FRONTS CROSSING THE
AREA...WITH MAXIMUM POPS DURING DAYTIME HEATING. CAPE IS EXPECTED TO
BE AT A MAXIMUM ALONG AND AHEAD OF THE PRIMARY BOUNDARY SATURDAY
AFTERNOON. NAM SOUNDINGS LOOK MORE FAVORABLE FOR SEVERE WEATHER THAN
GFS SOUNDINGS. A DECREASE IN POPS WILL BE PERMITTED BEHIND THE FRONT
SATURDAY NIGHT AND SUNDAY...BUT SMALL POPS WILL LINGER ALONG THE
BLUE RIDGE PER THE GFS SOLUTION... AS THE SECOND AND WEAKER
SHORTWAVE ARRIVES. LIFT AND MOISTURE WITH THE SECOND SHORTWAVE ARE
DEPICTED AS BEING MORE SHALLOW THAN WITH THE FIRST. TEMPERATURES
WILL BE ABOVE NORMAL...BUT WITH A SLIGHT DECREASE ON SUNDAY IN THE
WAKE OF THE SECOND FRONT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 140 PM THURSDAY...MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT
WITH RESPECT TO THE GENERAL PATTERN TO START OFF THE PERIOD...THE
CWFA ORIENTED NEAR THE BASE OF EASTERN CONUS TROUGH. THE WEAK SFC
FRONT WHICH IS PROGGED TO SLIP INTO THE CAROLINAS THIS WEEKEND IS
FCST TO STEADILY WEAKEN AS IT STALLS ACRS THE COASTAL PLAIN. ON A
REGIONAL SCALE...GREATEST DIURNAL TSTM CVRG SHOULD WIND UP ORIENTED
ALONG AND COASTWARD OF SFC FRONT...BUT APPROACHING IMPULSE WITHIN
THE WNW FLOW SHOULD BE ABLE TO TRIGGER AT LEAST SCATTERED ACTIVITY
ACRS THE WESTERN CAROLINAS ON TUESDAY. MAX TEMPERATURES FOR THE NEW
DAY 4 AND 5 WILL BE PRETTY TYPICAL FOR LATE JULY...WITHIN A FEW DEG
F OF CLIMO. DURING THE LATTER HALF OF THE PERIOD...AFOREMENTIONED SFC
FRONT BECOMES INCREASINGLY FRONTOLYTIC AND THE MEAN PATTERN...
EASTERN CONUS TROUGH...CHANGES LITTLE. GIVEN THE AMPLITUDE OF THE
PATTERN AND THE POTENTIAL FOR ADDITIONAL CHUNKS OF ENERGY TO ROTATE
THRU...FEEL THAT SOLID MAINLY DIURNAL TSTM CHANCES WILL EXIST EACH
DAY WITH TEMPERATURES STILL VERY CLOSE TO CLIMO.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...CONVECTIVE THREAT APPEARS NIL THIS AFTERNOON AS A CAPPING
INVERSION IS EXPECTED TO HOLD FIRM. EXPECT MCLR SKIES THROUGH
TONIGHT WITH SCT CU DEVELOPING LATE FRI MORNING. WINDS WILL REMAIN
GENERALLY LIGHT SW...EXCEPT FOR A FEW GUSTS TO AROUND 12KT LATE THIS
AFTERNOON.
ELSEWHERE...SIMILAR CONDITIONS TO KCLT EXCEPT FOR SOME LIGHT FOG AT
KAVL EARLY FRI. SLIGHT CHC POPS SHOULD REMAIN LIMITED TO THE MTNS THIS
AFTN.
OUTLOOK...CHANCE FOR THUDNERSTORMS WILL INCREASE FRI AS A SHORTWAVE
AND ASSOC WEAK COLD FRONT MOVE IN FROM THE NW. ANOTHER CHANCE FOR
THUNDERSTORMS WILL OCCUR SAT AFTERNOON AS ANOTHER COLD FRONT MOVES
THROUGH. THEN EXPECT A DAILY CHANCE FOR AFTERNOON CONVECTION INTO
THE MIDDLE OF NEXT WEEK...FIRST OVER SOUTHERN AREAS ON SUNDAY THEN
AREA WIDE AS 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.
HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR GAZ029.
NC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ071-072-082.
HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR NCZ071-072-082.
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ009-011>014-
019.
HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR SCZ009-011>014-
019.
&&
$$
SYNOPSIS...CSH
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...CSH
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
132 PM EDT THU JUL 26 2012
.SYNOPSIS...
MOISTURE WILL BE ON THE INCREASE FRIDAY OUT AHEAD OF AN APPROACHING
WEAK COOL FRONT. THIS FRONT WILL SETTLE INTO AND MOVE THROUGH THE
REGION OVER THE WEEKEND. SURFACE HIGH PRESSURE WILL BUILD BACK OVER
THE AREA LATER SUNDAY AND REMAIN THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 100 PM...CURRENT TEMP/DEWPOINT TRENDS STILL ON TRACK. STILL
EXPECT THAT ANY DEEP CONVECTION THIS AFTERNOON WILL BE WIDELY
SCATTERED OVER THE HIGH TERRAIN OF WESTERN NC. ONLY ADJUSTMENT TO
POP GRID IS TO ADD WIDELY SCT THUNDERSTORMS IN THE 00Z-03Z TIMEFRAME
TO PARTS OF NE GA AND THE WESTERN UPSTATE AS A WEAK VORT MAX MOVES
NE OUT OF GA. 12Z NAM/GFS AND RAP SHOWING SOME CONVECTIVE RESPONSE
IN THAT AREA.
PREVIOUS DISCUSSION:
NAM BUFKIT SOUNDINGS FROM THE 06Z RUN INDICATE A SUBTLE WARM NOSE IN
THE 5K-8K LAYER AT ALL PIEDMONT SITES WHICH SERVES TO PUT A CAP ON
ANY DEEP CONVECTION. IN THE MOUNTAINS...LFC`S LOWER TO AROUND 5KFT
WHICH MAY BE ENOUGH TO ALLOW SOME ISOLATED STORMS TO DEVELOP OVER
THE HIGH TERRAIN BY MIDAFTERNOON. THEREFORE...WILL MAINTAIN THE
WIDELY SCATTERED COVERAGE TYPE POPS OVER THE MOUNTAINS FOR THIS
AFTERNOON. CONVECTION SHOULD RAPIDLY DIMINISH BY LATE DAY.
ISOLATED TO SCATTERED CONVECTION WILL COME TO AN END RATHER QUICKLY
THIS EVENING AS FURTHER WARMING ALOFT NEARLY CAPS SOUNDINGS. THE
MODEL DEPICT SOME INCREASE IN LOW LEVEL MOISTURE THIS EVENING AT
AROUND 850 MB...BUT THIS SHOULD RESULT IN NO MORE THAN SCATTERED LOW
CLOUDS. MINIMUM TEMPERATURES WILL BE ALMOST FIVE DEGREES ABOVE
NORMAL UNDER THE UPPER RIDGE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH AN UPPER TROF DEEPENING OVER THE SE CONUS AND A STEEP
UPPER RIDGE BUILDING HIGHER OVER THE WESTERN CONUS. THE TROF AXIS IS
EXPECTED TO MOVE OVER THE CAROLINAS SATURDAY AFTERNOON WITH A WEAK
H5 SHORTWAVE DROPPING DOWN THE BACKSIDE OF THE UPPER RIDGE BY THE
END OF THE PERIOD 12Z SUNDAY.
ON FRIDAY...A WEAK COLD FRONT WILL MOVE ACROSS THE SOUTHERN
APPALACHIANS DURING THE AFTERNOON AND REACH OUR DOORSTEP BY FRIDAY
EVENING. THE LATEST MODEL RUNS ARE SUGGESTING THAT THE PREFRONTAL
ENVIRONMENT MAY NOT BE AS UNSTABLE AS PREVIOUSLY EXPECTED WITH CAPE
VALUES TRENDING DOWNWARD INTO THE 1000 TO 1500 J/KG RANGE WITH
LITTLE CIN. THERE IS ALSO SOME UPPER LVL DIVERGENCE JUST AHEAD OF
THE FRONT MOSTLY CONFINED TO THE NC MTS. THE BEST UPPER FORCING
HOWEVER...LOOKS LIKE IT WILL REMAIN TO OUR NORTH. WE WILL PROBABLY
SEE SOME SORT OF LINE OF MULTICELL TS MOVING INTO WESTERN NC BY MID
TO LATE AFTERNOON WITH SOME OF THE CONVECTION BECOMING SEVERE...BUT ITS
LOOKING LIKE IT MAY NOT BE ABLE TO PUSH VERY FAR SE ONCE WE LOSE
DAYTIME SFC HEATING. THE LATE DAY CONVECTION SHOULD ALLOW HIGH TEMPS
TO REACH THE U90S AGAIN EAST OF THE MTNS. RETURN FLOW AHEAD OF THE
FRONT WILL SUPPORT DEWPOINT VALUES IN THE U60S. THE COMBINATION OF
HOT TEMPERATURES AND MODERATE HUMIDITY SHOULD PRODUCE HEAT INDEX
VALUES ALONG AND EAST OF I-85 NEAR 105 DEGREES DURING THE LATE
AFTERNOON. THEREFORE...HEAT ADVISORY CRITERIA MAY BE REACHED EAST OF
I-85.
ON SATURDAY...THE CWA SHOULD REMAIN IN A POST FRONTAL
ENVIRONMENT...WITH NW LLVL WINDS AND DOWNSLOPE FLOW. LOWER
THICKNESSES WILL SUPPORT HIGHS ABOUT A CATEGORY COOLER THAN THE
PREVIOUS COUPLE OF DAYS. FORECAST SOUNDINGS CONTINUE TO SHOWS CAPE
VALUES AROUND 2000 J/KG DURING THE AFTERNOON. HOWEVER...A SHALLOW
LAYER OF CIN MAY EXIST BELOW THE LFC AND AND A A WEAK MID LVL
INVERSION COULD LIMIT ANY DEEP CONVECTION. GIVEN THE INSTABILITY AND
THE PASSAGE OF THE MID LEVEL TROF...I KEPT A SLIGHT CHANCE POP OVER
MOST OF THE FCST AREA DURING THE AFTERNOON/EARLY EVENING. IF
CONVECTION DOES DEVELOP...FAVORABLE THETA-E LAPSE RATES COULD
SUPPORT A DAMAGING WET MICROBURST OR 2.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 215 AM EDT THURSDAY...THE MEDIUM RANGE FCST PICKS UP AT 12Z ON
SUNDAY WITH THE UPPER TROF AXIS MOVING OFF THE EASTERN SEABOARD AND
A WEAK H5 SHORTWAVE APPROACHING THE CWFA. OVER THE REMAINDER OF THE
PERIOD...WE STAY UNDER THE INFLUENCE OF THE UPPER TROF WHILE THE
UPPER RIDGE MAINTAINS ITSELF OVER THE MIDWEST. NO SIGNIFICANT
CHANGES WERE NEEDED TO THE FCST.
PREVIOUS DISCUSSION...
AS OF 200 PM EDT WEDNESDAY...THE LATEST MODELS CONTINUE TO
INDICATE THAT THE UPPER TROUGH PERSISTS OVER THE EASTERN CONUS AND A
BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE REMAIN IN PLACE OVER THE
GREAT PLAINS THROUGH THE EXTENDED FORECAST PERIOD. AT THE
SURFACE...A FAIRLY STRONG HIGH PRESSURE IS EXPECTED TO BUILD ACROSS
THE REGION FROM THE NORTH BY LATE SATURDAY AND REMAINS THROUGH
SUNDAY FOR MOSTLY DRY WEATHER WITH SEASONABLY WARM TEMPERATURES. AS
THE HIGH MOVES OFF TO THE EAST MONDAY...A SURFACE LOW PRESSURE IS
EXPECTED TO DEVELOP OVER THE CAROLINAS AND LINGERS INTO WEDNESDAY.
THIS WILL RESULT IN UNSETTLED WEATHER PATTERN AND COOLER
TEMPERATURES ACROSS MUCH OF OUR CWA. TEMPERATURES WILL REMAIN
NEAR...OR A COUPLE DEGREES ABOVE NORMAL THROUGH TUESDAY WITH
AFTERNOON HIGHS IN THE LOW 90S OVER THE PIEDMONT. TEMPERATURES WILL
DROP 5-10 DEGREES BY WEDNESDAY WITH HIGHS IN THE MID 80S OVER THE
PIEDMONT AND 70S MTNS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...CONVECTIVE THREAT APPEARS NIL THIS AFTERNOON AS A CAPPING
INVERSION IS EXPECTED TO HOLD FIRM. EXPECT MCLR SKIES THROUGH
TONIGHT WITH SCT CU DEVELOPING LATE FRI MORNING. WINDS WILL REMAIN
GENERALLY LIGHT SW...EXCEPT FOR A FEW GUSTS TO AROUND 12KT LATE THIS
AFTERNOON.
ELSEWHERE...SIMILAR CONDITIONS TO KCLT EXCEPT FOR SOME LIGHT FOG AT
KAVL EARLY FRI. SLIGHT CHC POPS SHOULD REMAIN LIMITED TO THE MTNS THIS
AFTN.
OUTLOOK...CHANCE FOR THUDNERSTORMS WILL INCREASE FRI AS A SHORTWAVE
AND ASSOC WEAK COLD FRONT MOVE IN FROM THE NW. ANOTHER CHANCE FOR
THUNDERSTORMS WILL OCCUR SAT AFTERNOON AS ANOTHER COLD FRONT MOVES
THROUGH. THEN EXPECT A DAILY CHANCE FOR AFTERNOON CONVECTION INTO
THE MIDDLE OF NEXT WEEK...FIRST OVER SOUTHERN AREAS ON SUNDAY THEN
AREA WIDE AS 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...JPT
NEAR TERM...LG
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
114 AM EDT THU JUL 26 2012
.SYNOPSIS...
A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE
REGION TONIGHT THROUGH THURSDAY BRINGING VERY WARM AND MUGGY
CONDITIONS. A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CAROLINAS
AND NORTHEAST GEORGIA LATE FRIDAY AND INTO SATURDAY. ANOTHER RIDGE
OF HIGH PRESSURE BUILDS BACK IN SUNDAY AND REMAINS THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 110 AM...QUIET TREND CONTINUES WITH SCT SKIES ACROSS MOST OF
THE CWA. ONLY MINOR TWEAKS WERE MADE FOR OVERNIGHT CONDITIONS.
AS OF 1025 PM...OTHER THAN A FEW LINGERING SHRA OVER THE FRENCH
BROAD VALLEY...THE RADAR IS CLEAR. CANNOT COMPLETELY RULE OUT
ANOTHER SHOWER OR TWO OVER THE MTNS TONIGHT...BUT SHUD BE PRECIP
FREE AFTER MIDNIGHT. CIRRUS WILL SLOWLY DIMINISH OVERNIGHT AS WELL
WITH PATCHY FOG ON THE INCREASE. MAIN UPDATES WERE FOR CURRENT
CONDITIONS.
AS OF 755 PM...CONVECTION RAPIDLY DIMINISHING ACROSS THE AREA AND
SHUD END WELL BEFORE MIDNIGHT. HOWEVER...AN ISOLATED CELL CANNOT BE
RULED OUT BEFORE THEN. CLOUDS DIMINISH OVERNIGHT WITH PATCHY FOG
DEVELOPING OUTSIDE OF THE MTNS...WITH PATCHY DENSE FOG IN THE MTN
VALLEYS. LOWS STILL EXPECTED TO BE ABOVE NORMAL.
AS OF 430 PM...CONVECTION FINALLY TAKING OFF ACROSS NC WITH SCT
COVERAGE THERE AND ISOLATED OVER THE UPSTATE. EXPECT SCT COVERAGE
ALL AREAS FOR THE REST OF THE AFTERNOON...WITH SLIGHTLY BETTER
COVERAGE OVER THE NC PIEDMONT. STORMS BECOME ISOLATED ACROSS THE
MTNS BY EARLY EVENING...THEN TAPER OFF FROM NORTH TO SOUTH BY
MIDNIGHT. OTHERWISE...MAIN ADJUSTMENTS WERE FOR CURRENT CONDITIONS.
SO FAR THE WORKED-OVER AIRMASS BEHIND THIS MORNING/S MCS HAS NOT
SPAWNED ANY NEW CONVECTION. HOWEVER...THE CU FIELD IS BECOMING
BETTER DEFINED AND RAP SOUNDINGS SHOW VERY HIGH SURFACE-BASED CAPE
VALUES...PARTICULARLY ALONG AND JUST EAST OF THE BLUE RIDGE.
THEREFORE IT SHOULDN/T BE TOO MUCH LONGER BEFORE CONVECTION BEGINS
TO DEVELOP OVER THE HIGH TERRAIN. THE DEEP LAYER SHEAR IS ABOUT 20
KTS FROM THE NORTHEAST...AND ANY CELLS THAT DO DEVELOP SHOULD DRIFT
INTO THE FOOTHILLS AND POSSIBLY THE WESTERN PIEDMONT. THE WRF-ARW
AND 4KM SPC WRF-NMM ARE BOTH ALREADY WAY OVERDONE WITH CONVECTION
OVER THE REGION...THOUGH THEY DO INSIST THAT VIGOROUS DEVELOPMENT
WILL OCCUR.
THE BOTTOM LINE IS THAT I/LL CONTINUE TO CARRY CHANCE POPS THE REST
OF THE AFTN AND EVENING HOURS...WITH THE HIGHEST POPS ACROSS THE
MTNS AND THE LOWEST ACROSS THE PIEDMONT. HOWEVER...WITH SUCH AN
UNSTABLE ATMOSPHERE AND SEVERAL WEAK BNDRY/S OVER THE REGION IT/S
ENTIRELY POSSIBLE THAT SCATTERED STORMS...ONCE THEY FORM...WILL WORK
SOUTHEASTWARD ACROSS MUCH OF THE REGION DURING THE EVENING HOURS. A
FEW SEVERE STORMS ARE A GOOD BET ONCE THEY START TO FIRE.
THE ATMOSPHERE WILL WARM UP CONSIDERABLY TOMORROW AS THE CENTER OF A
HOT DEEP LAYER RIDGE MOVES ACROSS THE REGION. HEAT INDEX VALUES
SHOULD RISE INTO THE HEAT ADVISORY CRITERIA RANGE FOR SEVERAL HOURS
IN THE AFTERNOON ACROSS THE CHARLOTTE METRO AREA...THE SOUTHERN
UPSTATE AND IN ELBERT COUNTY GEORGIA. CLOSER TO THE MOUNTAINS
DEWPOINTS ARE EXPECTED TO MIX OUT ENOUGH IN THE AFTERNOON TO KEEP
THE HEAT INDEX BELOW ADVISORY CRITERIA. WITH WARMING MID LEVEL
TEMPS...VERY LITTLE SHEAR AND DEWPOINTS MIXING OUT DURING THE
AFTN...CONVECTION IS EXPECTED TO BE ISOLATED AND MAINLY CONFINED TO
THE MOUNTAINS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AS OF 230 PM EDT WEDNESDAY...ON FRIDAY...A COLD FRONT WITH ACTIVE
PRE-FRONTAL CONVECTION IS EXPECTED OVER MIDDLE KY/TN DURING THE PRE
DAWN HOURS. THE FRONT AND PRE-FRONTAL TROF WILL APPROACH THE
SOUTHERN APPALACHIAN REGION DURING THE MORNING AS A L/W TROF DEEPENS
OVER THE MID WEST. CONVECTION IS EXPECTED OVER THE MTNS BY MID DAY...PUSHING
EAST OF THE MTNS DURING THE AFTERNOON AND EVENING. THE ENVIRONMENT
AHEAD OF THE CONVECTIVE BAND WILL FEATURE LLVL BULK SHEAR VALUES
APPROACHING 20 KTS WITH CAPE RANGING FROM 1500 TO 2000 J/KG. A FEW
ORGANIZED STORM CLUSTERS MAY DEVELOP ALONG AND AHEAD OF THE
FRONT...POSSIBLY YIELDING DAMAGING WINDS AND HAIL.
THE LATE DAY PASSAGE OF CONVECTION SHOULD ALLOW HIGH TEMPERATURES TO
REACH THE U90S EAST OF THE MTNS. RETURN FLOW AHEAD OF THE FRONT WILL
SUPPORT DEWPOINT VALUES IN THE U60S. THE COMBINATION OF THE HOT
TEMPERATURES AND MODERATE HUMIDITY SHOULD YIELD HEAT INDEX VALUES
ALONG AND EAST OF I-85 TO REACH NEAR 105 DURING THE LATE AFTERNOON.
HEAT ADVISORY CRITERIA MAY BE REACHED EAST OF I-85.
ON SATURDAY...THE CWA SHOULD REMAIN LARGELY IN A POST FRONTAL
ENVIRONMENT...WITH NW LLVL WINDS. DOWNSLOPE FLOW AND LINGERING MILD
THICKNESSES WILL SUPPORT HIGHS IN THE U80S ACROSS THE MTN VALLEYS
AND MID 90S ALONG AND EAST OF I-85. DEWPOINTS MAY ALSO DECREASE A
FEW DEGREES IN THE WAKE OF THE FRONT. FORECAST SOUNDINGS
CONTINUE TO SHOWS CAPE VALUES AROUND 2000 J/KG DURING THE
AFTERNOON. HOWEVER...A SHALLOW LAYER OF CIN MAY EXIST BELOW THE LFC
AND AND AN WEAK INVERSION WITHIN THE MID LEVEL MAY LIMIT DEEP
CONVECTION. GIVEN THE INSTABILITY AND THE PASSAGE OF THE MID LEVEL
TROF I WILL ADVERTISE SCHC POPS DURING THE AFTERNOON. IF CONVECTION
DOES DEVELOP...THETA-E LAPSE RATES IN THE MID 30S COULD SUPPORT A
DAMAGING WET MICROBURST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM EDT WEDNESDAY...THE LATEST MODELS CONTINUE TO
INDICATE THAT THE UPPER TROUGH PERSISTS OVER THE EASTERN CONUS AND A
BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE REMAIN IN PLACE OVER THE
GREAT PLAINS THROUGH THE EXTENDED FORECAST PERIOD. AT THE
SURFACE...A FAIRLY STRONG HIGH PRESSURE IS EXPECTED TO BUILD ACROSS
THE REGION FROM THE NORTH BY LATE SATURDAY AND REMAINS THROUGH
SUNDAY FOR MOSTLY DRY WEATHER WITH SEASONABLY WARM TEMPERATURES. AS
THE HIGH MOVES OFF TO THE EAST MONDAY...A SURFACE LOW PRESSURE IS
EXPECTED TO DEVELOP OVER THE CAROLINAS AND LINGERS INTO WEDNESDAY.
THIS WILL RESULT IN UNSETTLED WEATHER PATTERN AND COOLER
TEMPERATURES ACROSS MUCH OF OUR CWA. TEMPERATURES WILL REMAIN
NEAR...OR A COUPLE DEGREES ABOVE NORMAL THROUGH TUESDAY WITH
AFTERNOON HIGHS IN THE LOW 90S OVER THE PIEDMONT. TEMPERATURES WILL
DROP 5-10 DEGREES BY WEDNESDAY WITH HIGHS IN THE MID 80S OVER THE
PIEDMONT AND 70S MTNS.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
AT KCLT...AS UPPER RIDGE BUILDS OVER THE REGION EXPECT MCLR SKIES
OVERNIGHT WITH BRIEF TEMPO MVFR VSBY AROUND DAYBREAK. LGT SW WINDS
WILL INCREASE TO 10KT WITH SCT CU THIS AFTN.
ELSEWHERE...SIMILAR CONDITIONS TO KCLT EXCEPT FOR TEMPO IFR FOG AT
KAVL AROUND DAYBREAK. LOW END CHC POPS SHOULD REMAIN LIMITED TO THE
MTNS THIS AFTN.
OUTLOOK...CHANCE FOR CONVECTION WILL INCREASE FRI AS A SHORTWAVE AND
ASSOC COLD FRONT MOVE IN. THEN EXPECT AT LEAST SLIGHT CHC POPS INTO
THE MIDDLE OF NEXT WEEK AS UPPER TROF REMAINS OVER THE E COAST.
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 FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
GAZ029.
NC...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
NCZ071-072-082.
SC...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
SCZ009-011>014-019.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY/RWH/RB
SHORT TERM...NED
LONG TERM...JOH
AVIATION...RB
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1047 PM CDT FRI JUL 27 2012
.UPDATE...
DESPITE MODEL INSISTENCE TO THE CONTRARY...RADAR IMAGERY SHOWS
MCS CONTINUES TO MAINTAIN STRENGTH AS IT PROPAGATES SOUTHEASTWARD
ACROSS CENTRAL KENTUCKY. ADDITIONAL ACTIVITY IS ALSO DEVELOPING
WEST OF THE MCS ALONG THE ASSOCIATED OUTFLOW BOUNDARY.
TRAJECTORIES TAKE SOME OF THIS CONVECTION INTO OUR NORTHEAST
ZONES...SO WILL RAISE POPS TO CHANCE CATEGORY FOR THE NORTHERN
PLATEAU AREA AND EXPANDED THEM SOUTHWARD ACROSS EASTERN ZONES.
HAVE ALSO REMOVED POPS FOR ALL OTHER AREAS WEST OF I-65. NO OTHER
CHANGES TO FORECAST ATTM.
&&
.PREV DISCUSSION... /ISSUED 838 PM CDT FRI JUL 27 2012/
UPDATE...
RADAR IMAGERY THIS EVENING SHOWS A LINE OF STRONG TO SEVERE
THUNDERSTORMS TO OUR NORTH FROM EVANSVILLE INDIANA EASTWARD TO
JACKSON KENTUCKY...WITH DAMAGING WINDS AND SEVERE WIND GUSTS
REPORTED INCLUDING A WIND GUST OF 66 MPH AT LEXINGTON KY AND 53
MPH AT LOUISVILLE KY. LATEST SCANS SHOW GUST FRONT SURGING OUT
AHEAD OF LINE...SO EXPECTING A WEAKENING TREND OF THIS ACTIVITY
OVER THE NEXT COUPLE OF HOURS. IN FACT...ALL GUIDANCE INCLUDING
LATEST HRRR RUNS SHOW ACTIVITY DISSIPATING PRIOR TO REACHING THE
TN BORDER. HOWEVER...IN CASE ACTIVITY HOLDS TOGETHER LONG ENOUGH
TO ENTER OUR CWA WILL KEEP A SLIGHT CHANCE POP GOING FOR THIS
EVENING ACROSS NORTHERN ZONES MAINLY NORTH OF I-40...BUT HAVE
REMOVED POPS TO THE SOUTH. REST OF THE FORECAST IS ON TRACK AND
ONLY MINOR TWEAKS WERE MADE.
PREV DISCUSSION... /ISSUED 717 PM CDT FRI JUL 27 2012/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
WIND SHIFT LINE EMBEDDED IN A WEAK SURFACE TROUGH IS SLIPPING
SOUTHEAST THROUGH SOUTHERN INDIANA...FAR SOUTHERN ILLINOIS DOWN
THROUGH THE BOOTHEEL OF MISSOURI. CONVECTION OVER THE OHIO RIVER
VALLEY HAS FIRED MORE IN RESPONSE TO UPPER LEVEL JET/AND SURFACE
TROUGH WHILE CONVECTION OVER SOUTHEAST MISSOURI/BOOTHEEL SEEMS TO
BE MORE SUN DRIVEN. BELIEVE ACTIVITY CURRENTLY TO OUR NORTHWEST
WILL WEAKEN WITH SUNDOWN.
EXPECT MVFR LATE TONIGHT DUE TO FOG. WINDS ON SATURDAY WILL BEGIN
TO TURN MORE WESTERLY AS TROUGH ENTERS MID STATE. EXPECT A FEW
GUSTS BY AFTERNOON.
BOYD
PREV DISCUSSION... /ISSUED 312 PM CDT FRI JUL 27 2012/
DISCUSSION...SCATTERED CONVECTION IS OCCURRING ACROSS THE
TENNESSEE VALLEY THIS AFTERNOON, WITH A WARM, HUMID AIR MASS IN
PLACE ACROSS MIDDLE TENNESSEE AND A COLD FRONT STILL SITUATED
NORTH OF THE OHIO VALLEY. EXPECT THIS BOUNDARY TO DROP SOUTHWARD
ACROSS THE MID STATE OVERNIGHT, AND FOR THIS REASON AM LEAVING
ISOLATED POP`S IN THE FORECAST THIS EVENING. EXPECT DRIER AIR TO
ADVECT INTO MIDDLE TENNESSEE LATER TONIGHT AND TOMORROW, EVEN
THOUGH MOST PLACES WILL STILL SEE HIGHS IN THE 90`S. BELIEVE WE
WILL BE DRY THROUGH THE WEEKEND UNTIL MOISTURE BEGINS TO
ACCUMULATE AND A NORTHWEST FLOW DEVELOPS ALOFT. THEREFORE, LOOK
FOR ISOLATED/SCATTERED CONVECTION TO RETURN TO THE FORECAST BY
MONDAY. BOTH THE GFS AND EUROPEAN MODELS BRING A WEAK SURFACE
FRONT THROUGH MIDDLE TENNESSEE ON TUESDAY, SO LOOK FOR HIGHER
POP`S DURING THAT PERIOD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
838 PM CDT FRI JUL 27 2012
.UPDATE...
RADAR IMAGERY THIS EVENING SHOWS A LINE OF STRONG TO SEVERE
THUNDERSTORMS TO OUR NORTH FROM EVANSVILLE INDIANA EASTWARD TO
JACKSON KENTUCKY...WITH DAMAGING WINDS AND SEVERE WIND GUSTS
REPORTED INCLUDING A WIND GUST OF 66 MPH AT LEXINGTON KY AND 53
MPH AT LOUISVILLE KY. LATEST SCANS SHOW GUST FRONT SURGING OUT
AHEAD OF LINE...SO EXPECTING A WEAKENING TREND OF THIS ACTIVITY
OVER THE NEXT COUPLE OF HOURS. IN FACT...ALL GUIDANCE INCLUDING
LATEST HRRR RUNS SHOW ACTIVITY DISSIPATING PRIOR TO REACHING THE
TN BORDER. HOWEVER...IN CASE ACTIVITY HOLDS TOGETHER LONG ENOUGH
TO ENTER OUR CWA WILL KEEP A SLIGHT CHANCE POP GOING FOR THIS
EVENING ACROSS NORTHERN ZONES MAINLY NORTH OF I-40...BUT HAVE
REMOVED POPS TO THE SOUTH. REST OF THE FORECAST IS ON TRACK AND
ONLY MINOR TWEAKS WERE MADE.
&&
.PREV DISCUSSION... /ISSUED 717 PM CDT FRI JUL 27 2012/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
WIND SHIFT LINE EMBEDDED IN A WEAK SURFACE TROUGH IS SLIPPING
SOUTHEAST THROUGH SOUTHERN INDIANA...FAR SOUTHERN ILLINOIS DOWN
THROUGH THE BOOTHEEL OF MISSOURI. CONVECTION OVER THE OHIO RIVER
VALLEY HAS FIRED MORE IN RESPONSE TO UPPER LEVEL JET/AND SURFACE
TROUGH WHILE CONVECTION OVER SOUTHEAST MISSOURI/BOOTHEEL SEEMS TO
BE MORE SUN DRIVEN. BELIEVE ACTIVITY CURRENTLY TO OUR NORTHWEST
WILL WEAKEN WITH SUNDOWN.
EXPECT MVFR LATE TONIGHT DUE TO FOG. WINDS ON SATURDAY WILL BEGIN
TO TURN MORE WESTERLY AS TROUGH ENTERS MID STATE. EXPECT A FEW
GUSTS BY AFTERNOON.
BOYD
PREV DISCUSSION... /ISSUED 312 PM CDT FRI JUL 27 2012/
DISCUSSION...SCATTERED CONVECTION IS OCCURRING ACROSS THE
TENNESSEE VALLEY THIS AFTERNOON, WITH A WARM, HUMID AIR MASS IN
PLACE ACROSS MIDDLE TENNESSEE AND A COLD FRONT STILL SITUATED
NORTH OF THE OHIO VALLEY. EXPECT THIS BOUNDARY TO DROP SOUTHWARD
ACROSS THE MID STATE OVERNIGHT, AND FOR THIS REASON AM LEAVING
ISOLATED POP`S IN THE FORECAST THIS EVENING. EXPECT DRIER AIR TO
ADVECT INTO MIDDLE TENNESSEE LATER TONIGHT AND TOMORROW, EVEN
THOUGH MOST PLACES WILL STILL SEE HIGHS IN THE 90`S. BELIEVE WE
WILL BE DRY THROUGH THE WEEKEND UNTIL MOISTURE BEGINS TO
ACCUMULATE AND A NORTHWEST FLOW DEVELOPS ALOFT. THEREFORE, LOOK
FOR ISOLATED/SCATTERED CONVECTION TO RETURN TO THE FORECAST BY
MONDAY. BOTH THE GFS AND EUROPEAN MODELS BRING A WEAK SURFACE
FRONT THROUGH MIDDLE TENNESSEE ON TUESDAY, SO LOOK FOR HIGHER
POP`S DURING THAT PERIOD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
642 PM CDT FRI JUL 27 2012
.DISCUSSION...
00Z TAF DISCUSSION
&&
.AVIATION...
OTHER THAN THE LATE NIGHT/EARLY MONRING MVFR FOG AT LBX AND
CXO...VFR CONDITIONS TO PREVAIL FOR NEXT 24 HOURS. THERE MAY FEW A
FEW ISOLATED AFTERNOON SHOWERS OR THUNDERSTORMS ON SATURDAY...BUT
COVERAGE SHOULD BE LIGHT ENOUGH I WILL NOT MENTION THEM IN TAFS AT
THIS TIME. 44
&&
.PREV DISCUSSION... /ISSUED 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/
.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...39
AVIATION/MARINE...44
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1230 AM CDT THU JUL 26 2012
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...VFR CONDITIONS WILL PERSIST THROUGH THE NEXT 24 HOURS.
GENERALLY MODERATE WINDS ARE LIKELY AS HIGH PRESSURE OVER THE GULF
OF MEXICO INTERACTS WITH LOW PRESSURE OVER NORTHERN MEXICO. A WEAK
DISTURBANCE IN THE MIDDLE LAYERS OF THE ATMOSPHERE THAT RECENTLY
DEVELOPED OVER THE WESTERN GULF OF MEXICO MAY PRODUCE INCREASED
CLOUD COVER OVER DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY...
ESPECIALLY TOMORROW.
&&
.PREV DISCUSSION... /ISSUED 627 PM CDT WED JUL 25 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...HAVE MAINTAINED VFR CONDITIONS FOR THE NEXT 24 HOURS.
SURFACE WINDS WILL ONCE AGAIN PICK UP DURING THE DAY...ESPECIALLY
AS DAYTIME HEATING KICKS IN...AS WILL THE CLOUD COVER. THE BIG
QUESTION IN THE SHORT TERM REMAINS THE INFLUENCE OF A CONVECTIVE
COMPLEX THAT IS JUST OFFSHORE OF THE MEXICAN COASTLINE BETWEEN
TAMPICO AND BROWNSVILLE. MODELS HINT AT A VORT MAX MOVING NORTH
THURSDAY AND THURSDAY NIGHT...ALLOWING FOR ISOLATED TO SCATTERED
CONVECTION. AT THIS TIME AM NOT CONFIDENT THAT CONVECTION WILL
IMPACT REGIONAL AIRPORTS AND AS SUCH HAVE NOT MENTIONED ANY
CONVECTION IN THE TAF PACKAGE.
PREV DISCUSSION... /ISSUED 211 PM CDT WED JUL 25 2012/
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...THE MAIN CONCERN IN
THE SHORT TERM IS THE POTENTIAL INFLUENCE OF THE CONV COMPLEX THAT
HAS BEEN FIRING TODAY JUST OFFSHORE OF THE MEXICAN COASTLINE BETWEEN
BRO AND TAMPICO. BOTH THE RUC AND NAM PICK UP ON A MID LEVEL VORT
LIKELY INDUCED BY THIS CONV AND MOVE IT NORTHWARDS STEADILY THROUGH
THURS AND THURS NIGHT. THE UPPER LEVEL SUPPORT FROM THIS FEATURE
WILL COMBINE WITH THE FAIRLY ELEVATED CAPE VALUES EVIDENT FROM THE
CURRENT LAPS FIELDS AND THE 12Z BRO SOUNDING TO SET THE STAGE FOR
THE FORMATION OF ISOLD TO SCT CONV MAINLY ALONG AND JUST OFFSHORE OF
THE LOWER TX COASTLINE LATER TONIGHT INTO THURSDAY NIGHT.
THE NAM AND RUC GUIDANCE BOTH TRY TO PICK UP ON THE MID LEVEL VORT
LOCATED NEAR THE HEART OF THE CONV AND ADVECT IT STEADILY NORTHWARDS
ALONG OR JUST OFFSHORE OF THE SOUTH TX COASTLINE. THE GFS ALSO PICKS
UP ON THIS FEATURE AND MOVES IT NORTH TOWARDS THE LOWER TX COASTLINE
BUT UNDERPLAYS THE OVERALL DEEPER LAYER MOISTURE POOL OVER THE
REGION. SO GFS HAS LITTLE OR NO POPS FOR THE REGION WHILE THE NAM
BUILDS UP SOME HIGHER POPS NEAR THE LOWER TX COASTLINE. WILL BE
GOING WITH THE NAM GUIDANCE FOR BOTH TEMPS AND POPS SINCE THIS MODEL
APPEARS TO BE INITIALIZING THE BEST ON THIS CONV COMPLEX.
LONG TERM /FRIDAY THROUGH TUESDAY/...
AT THE ONSET OF THE LONG TERM PERIOD UPPER RIDGING BEGINS TO BUILD
OVER THE SOUTHEASTERN ROCKY MOUNTAIN REGION AND SHIFT MORE TOWARDS
THE CENTRAL PLAINS...WHILE AT THE SURFACE RELATIVELY STRONG RIDGING
IS PROGGED TO BE CENTERED OVER THE EAST CENTRAL GULF OF MEXICO AND
THE NORTHERN PLAINS. WEAK LEE TROUGHING IN RESPONSE TO A WEAK
RETREATING UPPER LOW MAY REMAIN PRESENT ENOUGH FRIDAY TO ALLOW FOR
ONE MORE BREEZIER THAN NORMAL DAY BUT THAT SHOULD QUICKLY REMOVE
ITSELF AS A PLAYER FROM OUR WEATHER PATTERN BY SATURDAY.
THE OVERALL THEME OF THE PATTERN WILL CONTINUE TO BE WARM...POSSIBLY
HOT...AND DRY. WINDS SHOULD BE FAIRLY STEADY AND SEASONABLE OUT OF
THE SOUTHEAST AT 10 TO 15 MPH IN THE AFTERNOON. PWAT VALUES REMAIN
FAIRLY LOW AND A SUBSIDENCE INVERSION WILL LIKELY SET UP IN SOME
FORM IN RESPONSE TO THE BUILDING RIDGING OVER NORTHERN TEXAS AND THE
CENTRAL PLAINS. THE BEST WINDOW FOR ANY PRECIP FOR NOW LOOKS TO BE
SUNDAY IN THE AFTERNOON HOURS AS GFS40/ECMWF BOTH SLIDE A LITTLE BIT
OF TROPICAL MOISTURE ASSOCIATED WITH A WEAK WAVE IN VIA A WEAKNESS
IN THE RIDGE TO THE EAST AND OUR NORTH. DID ADD SOME SCHC SHRA/TSRA
TO THIS PERIOD GIVEN THE REASONABLE CONSENSUS ON TIMING FROM EC/GFS.
A PRIMARY CONCERN IN THIS PERIOD MAY BE PROLONGED ABOVE NORMAL
TEMPERATURES. DEEP LAYER AND LOW LEVEL THICKNESSES WILL BE QUITE
HIGH WITH STRONG INSOLATION AMID FEW TO SCATTERED CLOUDS. THE
SURFACE FLOW IS PROJECTED TO BE A LITTLE MORE SOUTHEASTERLY THAN
SOUTHERLY...BUT A FEW VERY HOT DAYS WILL BE POSSIBLE GIVEN THE
STRENGTH OF THE RIDGE. BUMPED UP TEMPERATURES SLIGHTLY FROM THE
GOING FORECAST WHICH CONTINUES TO SIT A LITTLE ABOVE GUIDANCE
CONSENSUS. HEAT INDICIES FROM 105 TO 110 WILL BE VERY MUCH IN PLAY
DURING THE SUNDAY TO WEDNESDAY PERIOD...WITH HEAT ADVISORY CRITERIA
HEAT INDICIES POSSIBLE.
MARINE /TONIGHT THROUGH THURSDAY NIGHT/...CURRENTLY THE PGF ALONG
THE LOWER TX BAY AND GULF WATERS HAS PUSHED CONDITIONS UP INTO SCEC
LEVELS THIS AFTERNOON. EXPECT THIS PGF TO PERSIST THROUGHOUT THE
SHORT TERM PERIOD KEEPING THE BAY AND GULF WATERS CLOSE TO
SCEC/BORDERLINE SCA CRIT THROUGH TOMORROW NIGHT. THE MARINE CONV
PUSHING UP FROM THE SOUTH MAY BRIEFING BOOST THE WINDS AND SEAS UP
CLOSE TO SMW CRIT DUE TO THE CONV OUTFLOW. HOWEVER WILL NOT POST ANY
SCAS AT THIS TIME.
FRIDAY THROUGH SUNDAY....
PERSISTENT MODERATE SOUTHEASTERLY WINDS ARE EXPECTED DURING THE
PERIOD. THE STRONGEST WINDS FOR NOW ARE EXPECTED ON FRIDAY. SCEC
CONDITIONS ON THE LAGUNA IN THE AFTERNOON AND THE EVENING IN THE
OFFSHORE WATERS ARE POSSIBLE DURING THIS TIME. WINDS AND SEAS SHOULD
STAY BELOW SCEC CRITERIA SATURDAY AND SUNDAY WITH SEAS GENERALLY
EXPECTED TO BE BETWEEN THREE AND FIVE FEET.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1020 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA SATURDAY FROM THE NORTHWEST...
HIGH PRESSURE BUILDING INTO THE REGION FROM THE GREAT LAKES FOR
SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1015 PM EDT FRIDAY...
MAIN AXIS OF SHOWERS AND THUNDERSTORMS HAS MOVED SOUTHEAST OF THE
COUNTY WARNING AREA WITH ONLY ISOLATED SHOWERS IN THE PIEDMONT
COUNTIES OF NORTH CAROLINA. HAVE TRIMMED BACK CHANCE OF
PRECIPITATION EAST OF THE BLUE RIDGE FOR THE REST OF THE NIGHT.
BAND OF THUNDERSTORMS MOVING THROUGH WEST VIRGINIA AND KENTUCKY
WAS WEAKENING ON THE EASTERN END OF THE LINE OF STORMS. HRRR AND
LOCAL WRF DATA SHOWED PRECIPITATION DISSIPATING BEFORE REACHING THE
WESTERN COUNTY WARNING AREA. FOR NOW HAVE LOWERED CHANCE OF
PRECIPITATION IN THE WEST BUT WILL BE WATCHING THE PROGRESS AND
TRENDS OF STORMS IN WEST VIRGINIA AND KENTUCKY.
HAVE LOWERED MINIMUM TEMPERATURES BASED ON 9PM OBSERVATIONS AND
THE LATEST GUIDANCE. ALSO ADDED PATCHY FOG IN FOR THE FAVORED
WESTERN VALLEYS OVERNIGHT SINCE MOST LOCATIONS HAD RAIN THIS
AFTERNOON AND IT WILL BE A FEW MORE HOURS WITH A CLEAR SKY BEFORE
ANY OF THE CIRRUS FROM THE KENTUCKY/WEST VIRGINIA STORMS REACH THE
FORECAST AREA.
AS OF 600 PM...
TRIMMED WW531 GENERALLY FROM LYH-MTV LINE AND WEST IN VA. ALSO CLEARED
THE NC HIGH COUNTRY.
MESOSCALE CONVECTIVE SYSTEM WHICH EVOLVED OVER THE CWA DURING THE
AFTERNOON WILL EXIT THE CWA EARLY THIS EVENING...THREAT FOR
SEVERE WEATHER ENDING FOR THE RNK CWA BY SUNSET. ANTICIPATE
GRADUALLY OMITTING COUNTIES FROM WW 531 AS THE MCS MOVES EAST
BOUND.
ONCE THE STORMS CLEAR THE AREA...RESIDUAL DEBRIS CLOUDINESS MAY
LINGER THROUGH ABOUT MIDNIGHT...FOLLOWED BY CLEARING AND
DEVELOPMENT OF PATCHY FOG.
THE UPPER LEVELS OF THE ATMOSPHERE WILL GRADUALLY AMPLIFY WITH
TROUGHING OVER THE EASTERN CONUS THIS WEEKEND. ASSOCIATED SURFACE
COLD FRONT WILL CROSS THE OHIO VALLEY TONIGHT...PUSHING THROUGH
THE MID ATLANTIC REGION SATURDAY. CONVERGENCE ALONG THE FRONT IN
ADDITION TO INCREASING MID LEVEL LAPSE RATES FROM COOLING
TEMPERATURES ALOFT WILL RESULT IN ANOTHER ROUND OF THUNDERSTORMS
SATURDAY AFTERNOON. WITH 500 MB TEMPS AROUND M10...STORMS WILL BE
MORE CONDUCIVE FOR HAIL FORMATION.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 345 PM EDT FRIDAY...
AXIS OF SHORT WAVE TROF EXPECTED TO BE ALONG AND JUST EAST OF THE
BLUE RIDGE SATURDAY EVENING...AND FORECAST TO DRIFT EAST OF
BLACKSBURG FORECAST AREA BY MID TO LATE EVENING. AS A RESULT...
EXPECT ANY DIURNALLY-DRIVEN SHOWERS/STORMS IN PROXIMITY OF TROF TO
MOVE EAST OF THE EASTERN COUNTIES BY MID EVENING TO BE FOLLOWED BY
GRADUAL CLEARING. LITTLE OR NO PRECIPITATION EXPECTED DURING THE
EVENING WEST OF THE TROF AXIS ACROSS THE EXTREME WESTERN COUNTIES.
CLEARING SKIES...LIGHT OR CALM SURFACE-BASED WINDS...AND ARRIVAL OF
SLIGHTLY COOLER/DRIER AIR WITH INCREASING SUBSIDENCE ALOFT MAY SET
THE STAGE FOR DEVELOPMENT OF SOME PATCHY FOG BY DAYBREAK SUNDAY...
ESPECIALLY IN THE MOUNTAIN VALLEYS AND LOW LYING/SHELTERED AREAS OF
THE PIEDMONT. HAVE INCLUDED THIS POSSIBILITY IN GRIDS.
WEAK UPPER RIDGING IS EXPECTED TO BUILD BACK INTO THE AREA ON SUNDAY
BETWEEN THE EXITING TROF TO THE EAST AND APPROACH OF ANOTHER
UPSTREAM SHORT WAVE TROF MOVING SOUTHEAST OUT OF THE UPPER MIDWEST
INTO THE UPPER OHIO VALLEY. THIS WAVE NOT EXPECTED TO REACH/IMPACT
THE BLACKSBURG FORECAST AREA UNTIL MONDAY...SO SUNDAY SHOULD BE
PRECIPITATION FREE. PROXIMITY/PASSAGE OF SHORT WAVE ON MONDAY SHOULD
BRING ANOTHER DAY WHERE MAINLY DIURNALLY-DRIVEN SHOWERS/STORMS WILL
BE POSSIBLE.
MET AND MAV MOS GUIDANCE THROUGHOUT THE SHORT TERM PERIOD FAIRLY
CONSISTENT...AND INDICATIVE OF WHAT IS ALREADY DEPICTED IN EXISTING
SET OF GRIDS. THEREFORE...NO SIGNIFICANT CHANGES WERE MADE TO THE
THERMAL FIELDS IN THE GRIDDED FORECAST.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 345 PM EDT FRIDAY...
BLOCKING PATTERN WILL BECOME ESTABLISHED THROUGH THE LONG TERM
PERIOD AS BERMUDA HIGH ANCHORS OFF THE SOUTHEAST COAST...BROAD UPPER
RIDGE BUILDS OVER THE SOUTHWESTERN PORTION OF THE NATION...LOCKING
MEAN UPPER TROF IN FROM THE UPPER AND LOWER GREAT LAKES TO THE EAST
COAST.
PROXIMITY OF UPPER TROF WITH ASSOCIATED COOLER AIR ALOFT...AND
THREAT OF RIDGE-RUNNING SHORT WAVE TROFS EMBEDDED IN WEST TO
NORTHWEST UPPER FLOW WILL MAINTAIN DAILY THREAT FOR
SHOWERS/THUNDERSTORMS OVER THE BLACKSBURG FORECAST AREA ALONG WITH
SOMEWHAT MODIFIED TEMPERATURES...WITH THREAT OF PRECIPITATION
MAXIMIZED AS EACH WAVE PASSES THROUGH/NEAR THE AREA.
AS WOULD BE EXPECTED...SOME TIMING/PLACEMENT DISCREPANCIES EXIST
BETWEEN SOME OF THE LONGER-RANGE MODELS. HOWEVER...ONE WAVE LIKELY
TO IMPACT THE MID APPALACHIAN AND MID ATLANTIC REGION ON
TUESDAY...WITH ANOTHER ON WEDNESDAY...AND POTENTIALLY A THIRD IN THE
THURSDAY/FRIDAY TIME FRAME.
EXTENT OF DAILY CLOUD COVER AND PROXIMITY TO PRECIPITATION WILL
LARGELY GIVEN OVERALL TEMPERATURES THROUGH THE PERIOD...BUT
TEMPERATURES IN THE UPPER 70S TO MID 80S IN THE MOUNTAINS WITH LOWER
90S ACROSS THE PIEDMONT BY DAY...WITH 60S MOUNTAINS TO AROUND 70
EAST OF THE BLUE RIDGE AT NIGHT SEEM REASONABLE AND NOT ALL THAT FAR
FROM CLIMATOLOGICAL NORMALS.
HPC BIAS CORRECTED GUIDANCE USED TO POPULATE LONG RANGE GRIDDED
FIELDS...WITH ONLY SUBTLE TWEAKS TO REFLECT TOPOGRAPHICALLY DRIVEN
LOCAL CLIMATOLOGICAL BIASES AS/WHERE APPROPRIATE.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
AS OF 800 PM FRIDAY...
ALL SHOWER AND THUNDERSTORM ACTIVITY FROM THIS AFTERNOON HAS
EXITED THE AREA TO THE EAST...HOWEVER LATEST RADAR IMAGERY
INDICATES ANOTHER MCS MAKING ITS WAY SOUTHEAST ACROSS NORTHERN
KENTUCKY. LATEST BATCH OF SHORT TERM MODELS SUGGEST THAT THE
SYSTEM WILL MOVE NEAR OUR WESTERN BORDER DURING THE 28/04Z TO 28/05Z
TIME FRAME...WITH BEST CHANCES TO AFFECT BLF. HAVE ADDED VCTS TO
THE BLF AND LWB TAFS DURING THIS TIME TO ACCOUNT FOR THESE
STORMS...AND IF STORMS HOLD TOGETHER MAY NEED TO AMEND THE TAFS TO
MENTION TSRA. DOWNSLOPE MOVEMENT AND LACK OF SUPPORT FROM DAYTIME
HEATING SHOULD CAUSE THESE STORMS TO WEAKEN FURTHER EAST.
IN ADDITION TO STORM ACTIVITY...WILL ALSO SEE PATCHES OF DENSE
FOG DEVELOP THANKS TO THIS AFTERNOONS RAINFALL...ALTHOUGH CIRRUS
BLOWOFF FROM APPROACHING STORMS MAY INHIBIT NIGHTTIME
COOLING...AND THEREFORE FOG FORMATION IN SOME AREAS.
ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS IS LIKELY
SATURDAY...DEVELOPING AHEAD OF A COLD FRONT THAT WILL CROSS THE
LOCAL REGION SATURDAY AFTERNOON. AS WAS THE CASE TODAY...BEST
CHANCE FOR STORM ACTIVITY WILL BE FROM LATE MORNING THROUGH EARLY
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...PM
NEAR TERM...AMS/PM
SHORT TERM...WERT
LONG TERM...WERT
AVIATION...NF/PM
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1039 PM PDT Wed Jul 25 2012
.SYNOPSIS...
Low pressure off and along the coast propped up against higher
pressure in the vicinity of the Northern Rockies will keep a very
minor southwest to northeast oriented storm track in the vicinity
of Eastern Washington and Northern Idaho into next week. This
pattern will should result in near normal temperatures through
much of this and the following workweek.
&&
.DISCUSSION...
Update for tonight...Surface instability with uncapped CAPE around
1000 J/KG earlier today trigger scattered showers and isolated
thunderstorms over the northern mountains. With the loss of
daytime heating these are winding down although water vapor does
show a weak wave over the Washington Cascades that will be moving
north tonight. This in combination with mid level instability will
result in a chance for isolated showers persisting through the
night mainly north of Lake Chelan. Thus the forecast was updated
earlier to add this to the forecast. Another wave across Oregon
will be approaching Southeast Washington and southern Idaho
Panhandle late tonight into Thursday morning. Given very little activity
convection wise this evening and that HRRR shows no convection
through 14z (7 am) with this wave will continue the idea of mid
level ACCUS clouds moving across the Palouse, Lewiston area,
Blues, and Camas Prairie Thursday morning with no shower or
thunderstorm activity expected. Another round of thunderstorms is
still expected Thursday afternoon over the northern mountains
especially in the Cascades. JW
&&
.AVIATION...
06Z TAFS: A very weak wave track out of northeast Oregon Thursday
morning into Southeast Washington and the south Idaho Panhandle. Mid
and upper levels are expected to destabilize which may lead to some
elevated convection and isolated thunderstorms, but confidence is
low at this time due to only weak forcing. We are more likely to
just get ACCAS clouds with possible sprinkles. This activity will
move across KLWS and KPUW taf sites between 14Z-21Z. This activity
will propagate into KGEG/KSFF/KCOE after 18z. Thunderstorms will
again develop after 18z over the mountains near the Canadian border
especially in the Cascades. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 63 89 62 87 59 84 / 0 10 10 20 20 0
Coeur d`Alene 57 88 58 87 56 84 / 0 0 10 20 20 0
Pullman 52 88 56 87 53 83 / 0 10 10 20 20 0
Lewiston 64 95 66 94 63 91 / 0 10 10 20 20 0
Colville 56 91 58 90 56 87 / 10 10 10 20 20 10
Sandpoint 53 86 53 85 52 81 / 0 10 10 20 20 0
Kellogg 54 88 58 86 55 81 / 0 10 10 20 20 10
Moses Lake 61 93 62 92 58 88 / 0 0 0 0 10 0
Wenatchee 66 93 66 90 63 87 / 0 0 0 0 10 0
Omak 61 92 60 92 57 88 / 10 10 20 20 20 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
913 PM PDT Wed Jul 25 2012
.SYNOPSIS...
Low pressure off and along the coast propped up against higher
pressure in the vicinity of the Northern Rockies will keep a very
minor southwest to northeast oriented storm track in the vicinity
of Eastern Washington and Northern Idaho into next week. This
pattern will should result in near normal temperatures through
much of this and the following workweek.
&&
.DISCUSSION...
Update for tonight...Surface instability with uncapped CAPE around
1000 J/KG earlier today trigger scattered showers and isolated
thunderstorms over the northern mountains. With the loss of
daytime heating these are winding down although water vapor does
show a weak wave over the Washington Cascades that will be moving
north tonight. This in combination with mid level instability will
result in a chance for isolated showers persisting through the
night mainly north of Lake Chelan. Thus the forecast was updated
earlier to add this to the forecast. Another wave across Oregon
will be approaching Southeast Washington and southern Idaho
Panhandle late tonight into Thursday morning. Given very little activity
convection wise this evening and that HRRR shows no convection
through 14z (7 am) with this wave will continue the idea of mid
level ACCUS clouds moving across the Palouse, Lewiston area,
Blues, and Camas Prairie Thursday morning with no shower or
thunderstorm activity expected. Another round of thunderstorms is
still expected Thursday afternoon over the northern mountains
especially in the Cascades. JW
&&
.AVIATION...
00Z TAFS: Surface based convection across the northern mountains
will dissipate with sunset this evening as well as the shallow
cumulus over the basin. A very weak wave will cross through the
region out of northeast Oregon Thursday morning into the afternoon
(after 15Z). Mid and upper levels are expected to destabilize across
eastern WA and into the Idaho Panhandle as this wave moves south to
north across the region. This may lead to some elevated convection
and isolated thunderstorms, but confidence is low at this time due
to only weak forcing. We may only get some ACCAS with some light
rain or sprinkles. At this point, placed the best chance, albeit low
chances, at the KLWS and KPUW taf sites between 17Z-21Z. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 63 89 62 87 59 84 / 0 10 10 20 20 0
Coeur d`Alene 57 88 58 87 56 84 / 0 0 10 20 20 0
Pullman 52 88 56 87 53 83 / 0 10 10 20 20 0
Lewiston 64 95 66 94 63 91 / 0 10 10 20 20 0
Colville 56 91 58 90 56 87 / 10 10 10 20 20 10
Sandpoint 53 86 53 85 52 81 / 0 10 10 20 20 0
Kellogg 54 88 58 86 55 81 / 0 10 10 20 20 10
Moses Lake 61 93 62 92 58 88 / 0 0 0 0 10 0
Wenatchee 66 93 66 90 63 87 / 0 0 0 0 10 0
Omak 61 92 60 92 57 88 / 10 10 20 20 20 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
718 PM CDT FRI JUL 27 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.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 CIRCULATION SLOWLY DRIFTING EAST OF THE
FORECAST AREA THIS EVENING. HOWEVER...CYCLONIC FLOW AND RESIDUAL BOUNDARY
LAYER MOISTURE CONTINUE TO LINGER...THUS STILL SOME SCT-BKN AREAS
OF CU ALONG...WITH A FEW ISOLATED LIGHT SHOWERS DRIFTING SOUTH
ACROSS THE FORECAST AREA MAINLY OVER OVER NORTHEAST WISCONSIN.
SHOWERS ARE OF LITTLE CONSEQUENCE THUS NO MENTION IN TAFS FOR
EARLY THIS EVENING.
EXPECT CU/SC TO SLOWLY WANE AFTER SUNSET WITH GENERALLY CLEAR
SKIES EXPECTED AFTER ABOUT 03Z THIS EVENING. SURFACE HIGH PRESSURE
WILL BEGIN TO PUSH SOUTHEAST ACROSS THE FORECAST AREA OVERNIGHT
WITH NORTHEAST BOUNDARY LAYER WINDS BECOMING LIGHT AND VARIABLE
ACROSS NORTHCENTRAL WISCONSIN AFTER 02Z. NORTHEAST WINDS AROUND 10
MPH WILL PERSIST OVER EASTCENTRAL WISCONSIN AND FOX VALLEY A BIT
LONGER INTO THE EVENING AS GRADIENT WILL BE A BIT SLOWER TO RELAX
THERE.
AFTER MIDNIGHT...POSSIBLITY FOR PATCHY/AREAS OF DENSE FOG EXITS
PARTICULARLY ACROSS NORTHCENTRAL WISCONSIN. ALSO COULD BE SOME
PATCHY DENSE FOG OVER PARTS OF THE FOX VALLEY...ESPECIALLY IN
LOW-LYING AREAS AND WHERE SUBSTANTIAL RAINFALL HAS FALLEN OVER
THE PAST 48 HOURS. WILL BE MONITORING FOG DEVELOPMENT LATER THIS
EVENING.
SCT-BKN VFR CIGS EXPECTED TO DEVELOP AROUND MID-DAY SATURDAY AS
RESIDUAL BOUNDARY LAYER MOISTURE FROM RECENT RAINS WILL LINGER.
WINDS EXPECTED TO BE LIGHT AND VARIABLE THROUGH MID-DAY AS HIGH
PRESSURE DRIFTS ACROSS THE AREA. SOME SIGNAL FROM HIGHER
RESOLUTION MODELS OF LIGHT ONSHORE SOUTHEAST FLOW DEVLOPING
PERHAPS PENETRATING AS FAR WEST AS GRB...ATW AND OSH BY LATE
AFTERNOON.
ESB
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
631 PM CDT FRI JUL 27 2012
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
230 PM CDT FRI JUL 27 2012
MAIN CONCERN WILL BE CLEARING TONIGHT/FOG POTENTIAL...THEN RAIN
CHANCES THROUGH THE PERIOD.
CURRENT WATER VAPOR/RAP 500MB ANALYSIS SHOWING A WEAKENING/SLOWLY
FILLING CLOSED LOW CENTERED OVER NORTHERN LAKE MICHIGAN. COOLER
CYCLONIC FLOW AROUND THIS LOW STILL EXERTING ITS INFLUENCE OVER OUR
AREA WITH AN EXTENSIVE POOL OF INSTABILITY CUMULUS/STRATOCUMULUS.
RADAR WAS EVEN SHOWING A FEW SHOWERS MAINLY ALONG AND NORTHEAST OF
I-94. OTHERWISE...TEMPERATURES ACROSS THE AREA WERE IN THE LOWER/MID
70S ALONG/NORTHEAST OF I-94...AND IN THE UPPER 70S NEAR 80 ELSEWHERE.
THIS MORNINGS MODEL RUNS IN FAIRLY DECENT AGREEMENT THROUGH THE
PERIOD.
CUMULUS EXPECTED TO SCATTER QUICKLY THIS EVENING. HOWEVER...THE
NAM/RAP SHOW LINGERING 925-850MB RH INDICATIVE OF A LINGERING
STRATOCUMULUS LAYER INTO AT LEAST THIS EVENING...EVENTUALLY
SCATTERING OUT OVERNIGHT. GIVEN CLOUD COVER TODAY/SCATTERED SHRA
ACTIVITY...THE LOWER BOUNDARY LAYER WILL BE FAIRLY MOIST AND WITH
CLEARING SKIES/LIGHT TO CALM WINDS...PLAN ON SOME FOG DEVELOPMENT
LATER TONIGHT/EARLY SATURDAY MORNING. FAIRLY CONFIDENT ON FOG
FORMATION...BUT NOT CONFIDENT ON INTENSITY FOR POTENTIAL HEADLINE
CRITERIA. FOR NOW...HAVE INTRODUCED AREAS OF FOG IN THE GRIDS...WITH
WIDESPREAD FOG EXPECTED IN THE RIVER VALLEYS WHERE GOOD
RADIATION/STEAM FOG SETUP IS PRIME GIVEN MOST WATER TEMPERATURES
AROUND 80. WILL HAVE THE EVENING FORECASTER ASSESS THE SITUATION FOR
FURTHER ATTENTION/POTENTIAL FOR FOG HEADLINES.
FOR SATURDAY...LOOKING AT A MID-LEVEL SHORTWAVE TROUGH MOVING OUT OF
THE DAKOTAS INTO IA. NAM SHOWING MODERATE ISENTROPIC LIFT/MOISTURE
TRANSPORT AHEAD OF THIS WAVE AND A SURFACE WARM FRONT THAT WILL BE
PUSHING INTO WESTERN IA/NORTHERN MO DURING THE DAY. PLAN ON A
GENERAL INCREASE IN MID-LEVEL CLOUDINESS INTO THE AREA AS THE DAY
PROGRESSES WITH ISOLATED-SCATTERED SHRA/TS POSSIBLY MOVING INTO
PORTIONS OF NORTHEAST IA/SOUTHEAST MN IN THE AFTERNOON. HIGH TEMPERATURES
WILL BE A BIT TRICKY IN THIS SCENARIO GIVEN THICKENING CLOUD
COVER/POTENTIAL FOR SCATTERED PRECIPITATION. WILL GO WITH UPPER 70S
UNDER THE THICKER CLOUDS WITH LOWER 80S EXPECTED ELSEWHERE. BETTER
SHRA/ISOLD T CHANCES WILL BE SEEN SATURDAY NIGHT...MAINLY WEST OF
THE MISSISSIPPI RIVER AS LIFT CONTINUES AND BETTER COLUMN SATURATION
OCCURS.
SUNDAY THROUGH MONDAY NIGHT...GFS/NAM IN GOOD AGREEMENT IN BRINGING A
COUPLE WEAKER MID-LEVEL TROUGHS ACROSS THE AREA IN NORTHWEST FLOW
ALOFT. NOT COMPLETELY CONFIDENT ON TIMING BUT IT APPEARS THE BEST
CHANCES ARE FOCUSED ON MONDAY DURING THE DAY. MAY HAVE TO WATCH
MONDAY CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL AS THE NAM PUSHES
0-3KM MUCAPE INTO THE 3000-4000J/KG RANGE ALONG WITH AROUND 30KT
0-3KM BULK SHEAR. EC/GFS ALSO SHOW HIGHER CAPE LEVELS AS WELL.
.LONG TERM...TUESDAY THROUGH FRIDAY
230 PM CDT FRI JUL 27 2012
LATEST GFS/ECMWF IN FAIRLY DECENT AGREEMENT THROUGH THE EXTENDED
PERIOD WITH A RIDGE OF HIGH PRESSURE PERSISTING OVER THE WESTERN
CONUS. THIS LEAVES THE UPPER MISSISSIPPI RIVER VALLEY/FORECAST AREA
SUSCEPTIBLE TO A FEW EMBEDDED SHORTWAVE TROUGHS COMING THROUGH IN
THE NORTHWEST FLOW ALOFT. MODEL CONSENSUS KEEP INTERMITTENT SMALL
SHRA/TS CHANCES IN THROUGH THE PERIOD WITH TUESDAY NIGHT/FRIDAY THE
ONLY DRY PERIODS AT THIS TIME. OTHERWISE...APPEARS TEMPERATURES
SHOULD BE RIGHT AROUND NORMAL IN THE 80S.
&&
.AVIATION...TONIGHT AND SATURDAY
631 PM CDT FRI JUL 27 2012
ISOLATED SHOWERS TO THE EAST OF THE MISSISSIPPI RIVER WILL
DISSIPATE EARLY THIS EVENING...WITH SCATTERED CUMULUS HANGING ON
OVERNIGHT. BIGGEST CONCERN IS FOG POTENTIAL AS HIGH PRESSURE
BUILDS INTO THE REGION. ENOUGH CLEARING EXPECTED TO COMBINE WITH
THE LIGHT WINDS TO RESULT IN GOOD RADIATIONAL COOLING TONIGHT AND FAVORABLE
CONDITIONS FOR FOG FORMATION. HOWEVER...27.21Z RAP SOUNDING IS
SHOWING A FEW DEGREE SPREAD IN THE NEAR SURFACE TEMPERATURE/DEW
POINT PROFILE. HOWEVER...GFS LAMP INDICATING THE DEVELOPMENT OF
FOG OVERNIGHT. FOG WAS INTRODUCED WITH PREVIOUS SET OF TAFS AND
WILL CONTINUE IT WITH THE 00Z ISSUANCE. SCATTERED CUMULUS EXPECTED
THEN AFTER 15Z SATURDAY. HOWEVER...THERE WILL BE AN INCREASE IN
HIGH LEVEL MOISTURE IN THE AFTERNOON AHEAD OF THE NEXT WAVE. VERY
LOW PROBABILITIES EXIST FOR SOME SHOWERS TO AFFECT THE KRST SITE
AFTER 21Z...BUT DID NOT INCLUDE AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CDT FRI JUL 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DENVER CO
1249 PM MDT FRI JUL 27 2012
.HYDROLOGY...STRONGEST STORMS HAVE HAD AN UNCANNY KNACK OF
DEVELOPING IN/NEAR THE BURN SCARS SO FAR THIS AFTERNOON. STORM
MOVEMENT HAS BEEN SLOW AND NEW UPDRAFTS SEEM TO BE FIRING ON THE
FRINGE OF THE STORMS COLD POOL ON THE SOUTH SIDE. AS A
RESULT...OVERALL STORM MOTION IS A LITTLE SLOWER SO THREAT OF
MINOR FLOODING ISSUES IN THE BURN SCARS IS NOW MODERATE WHILE
THREAT OF VERY HEAVY RAIN AND MORE SIGNIFICANT FLASH FLOODING IS
STILL LOW. WILL CONTINUE TO MONITOR.
&&
.PREV DISCUSSION... /ISSUED 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 PRECIPITABLE 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
AREA FORECAST DISCUSSION
NWS MIAMI FL
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.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 92 79 89 / - 10 - 10
FORT LAUDERDALE 81 91 81 90 / - 10 - 10
MIAMI 80 92 80 89 / - 10 - 10
NAPLES 77 89 76 91 / - 10 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1005 AM EDT THU JUL 26 2012
.DISCUSSION...
THE H100-H70 RIDGE AXIS EXTENDING FROM THE NRN BAHAMAS INTO THE
CENTRAL GOMEX BASED ON LATEST RAP ANALYSIS. MORNING SOUNDINGS SHOW
MOISTURE DECREASING FROM N TO S ACRS THE FL PENINSULA: PWATS ARND
1.9" AT KJAX...DECREASING TO ARND 1.4" S OF KXMR-KTBW. LOW/MID LVL
MOISTURE QUITE LOW WITH H100-H85 MEAN RH VALUES HOVERING ARND
70PCT...H85-H50 VALUES AOB 45PCT. STRONG SUBSIDENCE INVERSIONS NOTED
IN THE H90-H80 LYR ON CENTRAL/S FL AND NRN BAHAMA SOUNDINGS. THIS IS
WELL REFLECTED IN THE REGIONAL MID LVL THERMAL PROFILE WITH H70
TEMPS ARND 10C...H50 TEMPS BTWN -5C AND -6C.
POSITION OF THE RIDGE AXIS WILL MAINTAIN A WARM SWRLY FLOW ACRS
CENTRAL FL THIS AFTN. TEMP/MOISTURE PROFILE INDICATES MINIMAL PRECIP
CHANCES. ANY CONVECTION WILL BE BRIEF AND LIMITED TO AREAS N OF THE
I-4 CORRIDOR WHERE LOW/MID LVL MOISTURE WILL BE HIGHEST AND MID LVL
TEMPS LOWEST. EVEN SO...THE LOW LVL THERMAL CAP WILL BE DIFFICULT TO
BREAK THRU WITHOUT MESOSCALE BOUNDARY INTERACTIONS...AND THE EAST
COAST SEA BREEZE LIKELY WILL BE SUPPRESSED N OF I-4 DUE TO A
STRONGER WIND FIELD.
MRNG PACKAGE LOOKS GOOD WITH BLO 20 POPS ALONG AND N OF I-4. DRY
AIR...LACK OF PRECIP...AND SWRLY FLOW WILL COMBINE TO PUSH MAX TEMPS
M90S OVER MOST OF THE CWA...L90S ALONG THE IMMEDIATE COAST S OF THE
CAPE WHERE THE SEA BREEZE FORMS. DEWPOINTS IN THE M/U70S WILL
COMBINE WITH THESE TEMPS TO EASILY PUSH HEAT INDICES INTO THE
100-105 RANGE. NO UPDATES PLANNED THIS MORNING.
&&
.AVIATION...
THRU 26/18Z...BRIEF MVFR CIGS BTWN FL015-025 ALL SITES...AREAS MVFR
VSBYS IN HZ E OF KMLB-OBE.
BTWN 26/18Z-26/24Z...ISOLD MVFR SHRAS/IFR TSRAS N OF KEVB-KBKV.
AFT 27/00Z...VFR ALL SITES.
&&
.MARINE...
NO HIGHLIGHTS...NO SIG CHANGES. ATLC RIDGE AXIS OVER S FL WILL
GENERATE A GENTLE TO MODERATE SW BREEZE THRU EARLY AFTN. SFC/BNDRY
LYR WNDSHFT TO S/SE BY EARLY AFTN AS THE EAST COAST SEA BREEZE DVLPS
AND DRIFTS INLAND. SEAS AOB 2FT NEARSHORE...2-3FT OFFSHORE. DOMINANT
PDS ARND 13SEC.
&&
.CLIMATE...
RECORD HIGHS FOR THU JULY 26:
DAYTONA BEACH 97 1992
ORLANDO 98 1936, 1914
MELBOURNE 98 1983
VERO BEACH 97 1983
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST/AVIATION.......BRAGAW
RADAR WATCH/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
152 AM EDT SAT JUL 28 2012
.PREV DISCUSSION... /ISSUED 1018 PM EDT FRI JUL 27 2012/
UPDATE...
CURRENT RADAR TREND SHOWS THE STRONG TSTMS THAT MOVED THROUGH CSG
AROUND 800 PM EDT ARE WEAKENING AND MOVING INTO SOUTHWEST GA.
OTHERWISE...THE AIRMASS OVER NORTH AND CENTRAL GA CONTINUES TO
STABILIZE. ONLY SCATTERED SPRINKLES OF LIGHT RAIN FROM MID LEVEL
MOISTURE FROM DISSIPATING TSTMS WAS OCCURRING OVER PORTIONS OF NORTH
GA. EXPECT ALL PRECIPITATION TO DIMINISH JUST AFTER MIDNIGHT. HAVE
LOWERED POPS ACCORDINGLY. PATCHY FOG WILL DEVELOP LATE TONIGHT
THROUGH SUNRISE IN AREAS WHERE MEASURABLE RAIN OCCURRED EARLIER
TODAY. OTHERWISE...NO OTHER CHANGES NEEDED AS FORECAST MIN TEMPS
ARE ON TRACK.
16
PREV DISCUSSION... /ISSUED 800 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 HYDROMETER 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
&&
.AVIATION...
06Z UPDATE...
A FRONT WILL SAG INTO THE AREA TODAY ALLOWING FOR GREATEST
MOISTURE AND TSRA CHANCES TO RESIDE OVER THE SOUTHERN MOST
TERMINALS OF CSG AND MCN. VERY TEMPTING TO REMOVE ALL MENTION OF
CONVECTION BASED ON MODEL PROJECTIONS BUT GOOD SHOT OF UPPER LEVEL
ENERGY ARRIVES LATE AND FEEL IT WILL BE JUST ENOUGH TO PRODUCE SCT
TSRA AT THE ATL ARE TERMINALS. TIMING IS DIFFICULT TO PIN DOWN BUT
LOOKS TO BE A LATE EVENING OR EVEN OVERNIGHT SCENARIO AT THIS POINT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON TSRA CHANCES.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 95 72 94 70 / 40 20 20 20
ATLANTA 93 75 92 72 / 40 10 20 10
BLAIRSVILLE 89 66 88 64 / 30 10 20 20
CARTERSVILLE 93 70 92 67 / 30 10 10 20
COLUMBUS 94 76 93 74 / 40 20 30 10
GAINESVILLE 91 73 93 71 / 30 20 20 20
MACON 94 74 94 71 / 40 20 30 20
ROME 94 70 93 67 / 30 10 10 20
PEACHTREE CITY 93 70 91 67 / 40 20 20 10
VIDALIA 95 76 94 74 / 40 30 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
459 AM EDT SAT JUL 28 2012
.SHORT TERM...
TODAY THROUGH SUNDAY NIGHT. BENIGN PATTERN IN SHORT TERM PD. 1021 MB
SFC HIGH ACRS NRN WI TO DROP SLOWLY SEWD INTO LWR GRTLKS BY MON AM.
STATIC MIDLVL REGIME FEATURING STRONG OK/NRN TX RIDGE CENTER WITH
MULTIPLE SHORTWAVES RIDING BROAD WRLIES ACRS NRN PLAINS/SRN
CANADA...THEN TRACKING INTO MEAN ERN STATES TROF. ANTICIPATE FURTHER
EXPANSION WITHIN 925MB THERMAL TROF ACRS SRN MI/NRN IN THIS AM AMID
TURBULENT N-NERLY 10-15KT FLOW PER KDTX VWP AND RAP POINT SNDGS.
RAPID MIXOUT OF CLOUDS COINCIDENT WITH RAPID EROSION OF LOW BASED
SUBSIDENCE INVERSION/RAPID RISING CCL/ENTRAINMENT OF SIG DRIER AIR
ALOFT. SLIGHT DOWNWARD NUDGE IN TEMPS TODAY PER AM CLOUD COVER/DEEP
NRLY FLOW/GUID CLUSTERING/SIMILAR THERMAL REGIME AS SEEN YDAY ACRS
SRN WI. SLIGHT NUDGE TOWARD NAM/ECMWF WRT NEXT MINIMAL TSRA CHCS
ACRS SWRN CWA LATE SUNDAY NIGHT/ERLY MONDAY MORNING. RATHER WEAK
PIECEMEAL ENERGY ACRS WRN/CNTL MT EMANATING FM STRONGER SRN BC
VORTEX TO TRACK INTO CNTL MS VLY LATE DY2. PSBL MCS DVLPG ACRS KS/MO
SUNDAY EVENING WITH EWD MAINTENANCE PER RAMPING NOCTURNAL JETLET
INTO ECNTL MO OVERNIGHT. EWD PUSH OF EML MAY BE LIMITED PER MORE
VEERED FLOW WITH ERN EXTENT AND RELEGATE HIEST CHCS ACRS CNTL
IL/CNTL IN TOWARD DAYBREAK...AND HAVE OMITTED MENTION ACRS NRN CWA
06-12 UTC MON.
&&
.LONG TERM... /MONDAY THROUGH FRIDAY.
IN COORDINATION WITH SHORT TERM PERIOD...HAVE OPTED TO LOWER POPS
MON/MON NGT GIVEN INCREASING SIGNALS FROM ECMWF AND GEFS OF LITTLE
OR NO PRECIP OCCURRING AS WEAK WAVE SET TO MOVE THROUGH LATE SUN
INTO MONDAY WILL BE SERIOUSLY LACKING ANY MSTR OR SIG
LIFT...LIMITING ITS EFFECTS MAINLY TO INCREASE IN MID LEVEL CLOUDS
AND MAYBE SOME LIGHT SHOWERS. SOMEWHAT STRONGER WAVES WILL MOVE
ACROSS THE NORTHERN/CENTRAL GREAT LAKES TUESDAY AND AGAIN THURSDAY.
WITH NW FLOW IN PLACE...MSTR WILL REMAIN CUT OFF WITH THESE SYSTEMS
AS WELL...BUT AT LEAST A BIT MORE IN THE WAY OF DYNAMICS WITH EACH
WAVE TO HANG ONTO CHC/SLGT CHC POPS...MAINLY IN NORTH AND EAST
SECTIONS.
WITH LITTLE CHANGE IN OVERALL FLOW...TEMPERATURES SHOULD REMAIN IN
THE 85 TO 90 DEGREE RANGE MUCH OF THE PERIOD WITH LOWER READING SEEN
WITH PASSAGE OF EACH WAVE AND ASSOCIATED CLOUDS/PRECIP. BY
FRIDAY...SLIGHTLY COOLER AIR MAY ARRIVE BEHIND THE THURSDAY
SYSTEM...BUT WILL ONLY SHAVE A FEW DEGREES OFF HIGHS COMPARED TO THE
REST OF THE WEEK.
&&
.AVIATION...
MOIST 950-900 MB LYR ACROSS SOUTHERN MICHIGAN WITH SUFFICIENT
TURBULENT MIXING IN BACKED/NERLY CLOUD LAYER FLOW TO AFFORD STRATUS
EXPANSION INTO NRN INDIANA ERLY THIS AM. RAPID MIXOUT OF SHALLOW
THERMAL TROF/SUBSIDENCE INVERSION TO AFFORD INCRSG CU/LCL THROUGH AM
HOURS...TO VFR MET CONDS BY 15 UTC THROUGH THE END OF FCST PD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK THROUGH THIS EVENING FOR INZ003.
MI...RIP CURRENT RISK THROUGH THIS EVENING FOR MIZ077.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MURPHY
LONG TERM...FISHER
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1150 PM CDT FRI JUL 27 2012
.AVIATION...
VFR CONDITIONS WILL BE OVER MUCH OF THE AREA THROUGH THE PERIOD.
A BROAD AREA OF HIGH PRESSURE WILL KEEP LIGHT WINDS OVER THE AREA.
THE WIND DIRECTION WILL BE MAINLY FROM THE NORTH OVERNIGHT AND
WILL VEER TO THE EAST SATURDAY. THERE IS SOME POTENTIAL FOR MVFR
VSBYS LATE TONIGHT AT KDBQ WITH A WEAK AREA OF LOW LEVEL
CONVERGENCE IN THE VICINITY.
DLF
&&
.PREV DISCUSSION... /ISSUED 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
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
124 AM EDT SAT JUL 28 2012
.AVIATION...
//DISCUSSION...
A LINGERING SURFACE TROUGH RESIDING WITHIN LOW LEVEL NORTHEAST FLOW
WILL MAINTAIN SOME POCKETS OF LOWER STRATUS THROUGH THE NIGHT.
LATEST SATELLITE TRENDS SUGGEST A PERIOD OF LOWER MVFR CONDITIONS
WILL EXIST FROM FNT DOWN THROUGH THE DETROIT CORRIDOR DURING THE
EARLY MORNING PERIOD. DRIER AIR WORKING IN FROM THE NORTH WILL HELP
MIX OUT THIS MOISTURE THROUGH THE LATTER HALF OF THE MORNING. HIGH
PRESSURE WILL THEN BRING A PERIOD OF MOSTLY CLEAR SKIES AND LIGHTER
NORTHEAST WINDS FOR THE LATTER HALF OF THE DAY.
//DTW THRESHOLD THREATS...
* NONE
&&
.PREV DISCUSSION...ISSUED 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.
&&
.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.
&&
$$
AVIATION.....MR
SHORT TERM...SC
LONG TERM....MM
MARINE.......SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS HASTINGS NE
440 AM CDT SAT JUL 28 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT. MULTIPLE FORECAST
CONCERNS...ESP TODAY AND SUNDAY...INCLUDING
TEMPERATURES...PRECIP CHANCES...AND FIRE WEATHER ISSUES.
SATELLITE AND UPPER LEVEL PROFILER DATA CONTINUE TO SHOW THE
REGION UNDER THE INFLUENCE OF HIGH PRESSURE/RIDGING CENTERED
OVER THE SRN PLAINS...WHILE A WEAK DISTURBANCE CONTINUES TO RIDE
AROUND THE EDGE OF THE RIDGE...CURRENTLY OVER NERN NEB/SERN SD.
ANOTHER DISTURBANCE IS CURRENTLY MAKING ITS WAY THROUGH WY...WHICH
CAN ALSO BE PICKED OUT VIA LIGHTNING DATA. WAS CONCERNED LAST
NIGHT THAT THE ACTIVITY MAY STAY JUST NORTH OF THE CWA...AND AT
THIS POINT...LOOKS LIKE HOW IT IS GOING TO TURN OUT. AT THE
SURFACE...THE CWA SITS BETWEEN HIGH PRESSURE EXTENDING FROM NRN IA
INTO ERN CANADA...AND LOW PRESSURE DRAPED ALONG THE HIGH/SRN
PLAINS...BRINGING SOUTHEASTERLY FLOW...WITH SPEEDS GENERALLY
NEAR/LESS THAN 10 MPH.
LOOKING TO THE REST OF TODAY AND INTO TONIGHT...CONTINUE TO SEE
THE POTENTIAL FOR THUNDERSTORM ACTIVITY ACROSS THE
CWA...PRIMARILY THIS AFTERNOON/EVENING. EVEN THIS CLOSE IN
TIME...PLENTY OF MODEL DIFFERENCES REMAIN. THE GENERAL STORY LIES
WITH THAT NEXT DISTURBANCE MOVING ONTO THE PLAINS...WHICH LOOKS TO
SPARK OFF THUNDERSTORMS ACROSS THE REGION. A SURFACE TROUGH AXIS
IS EXPECTED TO PUSH SOUTH THROUGH THE DAY...BUT WHERE IT EXACTLY
ENDS UP CONTINUES TO BE DEBATED BETWEEN MODELS. THE NAM REMAINS ON
THE MORE AGGRESSIVE SIDE OF THINGS WITH THE THUNDERSTORM
DEVELOPMENT...WITH THE GFS/EC SHOWING VERY LITTLE. WITH SUPPORT
FROM THE 00Z 4KM WRF AND HRRR ALSO TRENDED MORE TOWARD THE NAM
/BUT NOT NEARLY AS WIDESPREAD/...DECIDED TO UP POPS INTO THE 30
PERCENT RANGE...MAINLY ACROSS SC NEB. DIDNT RAISE ANY HIGHER DUE
TO THOUGHT THAT THE NAMS COVERAGE COULD BE OVERDONE. DID KEEP
LINGERING POPS INTO THIS EVENING...BUT EXPECT THINGS TO BE WINDING
DOWN PRIOR TO MIDNIGHT. AS FAR AS SEVERE WEATHER GOES...FEEL THAT
WHAT THUNDERSTORMS DO DEVELOP LATER TODAY COULD BE CAPABLE OF
DAMAGING WINDS...WITH FORECAST SOUNDINGS SHOWING GOOD MIXING
POTENTIAL AND PLENTY OF DRIER AIR IN THE LOWER LEVELS. WILL GO
AHEAD AND INSERT THAT POSSIBILITY IN THE HWO. COULDNT RULE OUT
SOME QUARTER SIZE HAIL...BUT WINDS LOOK TO BE MORE A THREAT.
AS FAR AS TEMPERATURES GO...ONLY MINOR ADJUSTMENTS WERE MADE...AND
STILL EXPECTED TO BE WARMER THAN FRIDAY...AS WARMER AIR ALOFT
CONTINUES TO BUILD IN FROM THE WEST. FORECAST CURRENTLY CALLING
FOR MID 90S IN THE NORTHEAST TO 100-105 ACROSS THE SW CORNER OF
THE CWA. AS MENTIONED ABOVE...FORECAST SOUNDINGS /ESP IN THE SW/
SHOW GOOD MIXING POTENTIAL...AND AFTERNOON DEWPOINTS REFLECT THAT
POSSIBILITY. COMBINED WITH THE EXPECTED INCREASINGLY MORE
SOUTHWESTERLY COMPONENT TO THE WINDS...BY MID
AFTERNOON...EXPECTING TO SEE DEWPOINTS IN THOSE SOUTHWESTERN
LOCATIONS FALL INTO THE LOWER 50S...WHILE LOCATIONS GENERALLY
ALONG/NORTH OF I80 LOOK TO REMAIN CLOSER TO THE LOWER 60 PERCENT
RANGE. DID NOT GO WITH ANY HEAT ADV HEADLINE FOR TODAY ACROSS NC
KS /WHERE HIGHS ARE HOTTEST/...AS THE LOWER DEWPOINTS EXPECTED TO
ACCOMPANY THOSE TEMPERATURES SHOULD KEEP HEAT INDEX VALUES FROM
EXCEEDING 105 DEGREES ON A WIDESPREAD BASIS.
FORECAST FOR TODAY DID RAISE SOME CONCERNS ABOUT FIRE
WEATHER...SEE FIRE SECTION BELOW FOR MORE INFORMATION.
AS WE GET INTO SUNDAY/SUNDAY NIGHT...THUNDERSTORM CHANCES REMAIN
IN THE FORECAST. KEPT THE MORNING HOURS DRY...BUT AS THIS LATEST
DISTURBANCE MOVES THROUGH AND EVENTUALLY EAST OF THE CWA...MODELS
HAVE COME INTO BETTER AGREEMENT SHOWING THE SURFACE BOUNDARY
PUSHING FURTHER SOUTH THROUGH THE CWA...EVENTUALLY SETTLING AT
LEAST NEAR THE NEB/KS STATE LINE...IF NOT FURTHER SOUTH. DEPENDS
ON THE MODEL. HAVE SOME LOW POPS IN DURING THE AFTERNOON ACROSS
SOUTHERN PORTIONS OF THE CWA...CLOSE TO WEAR THE BOUNDARY COULD
BE. MADE LITTLE CHANGE TO THE EVENING/OVERNIGHT POPS...THE GFS
CONTINUES TO CERTAINLY BE ON THE MORE WIDESPREAD SIDE OF
THINGS...BUT FORECAST REMAINS TRENDED TOWARDS BETTER SUPPORT
JUSTIFYING LOWER POPS. MODELS SHOW AN INCREASE IN TEMPERATURES
ALOFT ACROSS THE REGION ON SUNDAY...BUT WITH THE MORE EASTERLY
COMPONENT TO THE WINDS...HARD TO GO MORE THAN A COUPLE OF DEGREES
WARMER THAN TODAY /DIDNT MAKE NOTABLE CHANGES TO THE INHERITED
TEMPERATURES/. AM CONCERNED THAT THOSE EASTERLY WINDS ARE GOING
HAVE A GREATER IMPACT ON THE TEMPERATURES /PRIMARILY ACROSS SC
NEB/...AND UPCOMING SHIFTS WILL HAVE TO TAKE A LOOK AT THAT. IF
THE BOUNDARY DOESNT GET AS FAR SOUTH AS SAY THE 06Z NAM
SUGGESTS...WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR HEAT ADV
CRITERIA ACROSS NC KS. AT THIS TIME...WITH PLENTY OF UNCERTAINTY
WASNT GOING TO GO DOWN THAT ROAD.
UNCERTAINTY WITH THE PRECIPITATION CHANCES CONTINUES INTO
MONDAY...AND KEPT LOW POPS IN PLACE ACROSS THE CWA. MODELS RANGE
FROM VERY LITTLE GOING ON ANYWHERE...TO WIDESPREAD ACTIVITY ACROSS
PORTIONS OF SC NEB...TO ACTIVITY DRIFTING INTO THE WEST FROM
EARLIER DEVELOPMENT ACROSS THE HIGH PLAINS. CANT REALLY NAIL
DOWN BETTER SPECIFICS WITH THE POPS UNTIL THERE IS BETTER
AGREEMENT WITH ANY SOLUTION BETWEEN THE MODELS. THERE IS BETTER
AGREEMENT IN REGARD TO TEMPERATURES...WHICH SHOW HIGHS BEING
COOLER THAN ON SUNDAY...WITH LOWER/MID 90S IN NEB...MID/UPPER 90S
IN KS. KEPT THE INHERITED DRY FORECAST FOR MONDAY NIGHT IN PLACE.
.LONG TERM...TUESDAY THROUGH FRIDAY.
THE MAIN CONCERN FOR THE LONG TERM PERIOD WILL AGAIN FOCUS ON
CHANCES FOR SHOWERS AND THUNDERSTORMS. OTHERWISE...MADE VERY FEW
CHANGES TO THE EXTENDED.
WHILE AN UPPER LEVEL RIDGE REMAINS STEADFAST ACROSS THE WESTERN
TWO THIRDS OF THE CONUS TOWARDS THE BEGINNING OF THE LONG
TERM...AN UPPER LEVEL TROUGH OFF THE WESTERN COAST SLOWLY BEGINS
TO PUSH EASTWARD ACROSS CANADA...THUS HELPING BREAK DOWN THE UPPER
LEVEL RIDGE. IN ADDITION...NUMEROUS SHORT WAVES CONTINUE TO ROUND
THE TOP OF THE UPPER LEVEL RIDGE AND SKIRT ACROSS THE PLAINS.
ALTHOUGH TIMING AND PLACEMENT AS WELL AS RESOLUTION REMAIN
INCONSISTENT AMONG THE LONG TERM MODELS...THERE APPEARS TO BE SOME
CHANCE AT AN UPPER LEVEL DISTURBANCE PASSING THROUGH THE REGION
SOMETIME DURING THE LONG TERM PERIOD. AT THE SURFACE...LOW
PRESSURE ALONG THE NORTHERN ROCKIES IS EXPECTED TO SHIFT EASTWARD
ACROSS THE DAKOTAS...WHILE HIGH PRESSURE REMAINS SITUATED ACROSS
THE CENTRAL PLAINS...THROUGH AT LEAST THURSDAY MORNING. DEVELOPING
LOW PRESSURE ACROSS THE REGION ON THURSDAY...COMBINED WITH THE
POSSIBILITY OF AN UPPER LEVEL SHORT WAVE AND UPPER LEVEL JET
STREAK COULD CERTAINLY GENERATE SOME POPS ACROSS THE AREA. AT THIS
POINT...MODELS REMAIN TOO INCONSISTENT TO CONTINUE WITH SEVERAL
PERIODS OF SLIGHT CHANCE POPS. PER NEIGHBOR
COLLABORATION...CONTINUED A DRY FORECAST THROUGH MUCH OF THE
EXTENDED WITH THE EXCEPTION OF FRIDAY. FOR FRIDAY...MODELS ARE AT
LEAST IN AGREEMENT ON PLACEMENT OF A SURFACE LOW/TROUGH ALONG THE
HIGH PLAINS SHIFTING EASTWARD...AN UPPER LEVEL JET ACROSS PORTIONS
OF NEBRASKA...AND A WEAK UPPER LEVEL WAVE TRAVERSING THE REGION.
THUS ADDED SLIGHT CHANCES FOR POPS TO MOST OF THE OUTLOOK AREA ON
FRIDAY.
&&
.AVIATION...06Z KGRI TAF. VFR CONDITIONS ARE EXPECTED TO CONTINUE
THROUGHOUT THE TAF PERIOD. HOWEVER...A SURFACE LOW PRESSURE
SYSTEM/TROUGH AXIS WILL GRADUALLY SHIFT EASTWARD ALONG THE HIGH
PLAINS TODAY. AS A RESULT...SOUTHEAST WINDS WILL GRADUALLY SHIFT
TO MORE SOUTHERLY THIS MORNING AND EVENTUALLY TO THE SOUTHWEST
THIS AFTERNOON. WITH GOOD BOUNDARY LAYER MIXING THIS
AFTERNOON...WIND SPEEDS NEAR 15 KTS WITH GUSTS NEAR 20 KTS CAN BE
EXPECTED BEFORE BECOMING LIGHT AND VARIABLE IN THE EVENING. A
SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS ALSO REMAINS POSSIBLE
THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS NORTHERN NEBRASKA.
AT THIS TIME...NOT EXPECTING THESE SHOWERS TO SHIFT THROUGH THE
TAF SITE...SINCE THEY WILL LIKELY BE SCATTERED IN NATURE...BUT
SHOULD BE MONITORED. INCREASED CLOUD COVER WILL BE POSSIBLE THIS
AFTERNOON...SHOULD THUNDERSTORMS DEVELOP ACROSS NORTHERN NEBRASKA.
&&
.FIRE WEATHER...MAIN CONCERN IS GOING TO LIE ACROSS THE
SOUTHWESTERN THIRD OF THE CWA...WHERE THE BETTER MIXING
POTENTIAL...AND THUS LOWER DEWPOINTS AND HIGHER TEMPERATURES WILL
EXIST. DEBATED ISSUING A HEADLINE FOR PORTIONS OF NC KS THIS
AFTERNOON...AS FORECAST RELATIVE HUMIDITY VALUES ARE EXPECTED TO
FALL TO NEAR/JUST BELOW 20 PERCENT. THE LIMITING FACTOR LIES WITH
THE WINDS. THE MAJORITY OF MODEL DATA AND GUIDANCE KEEPS SUSTAINED
WIND SPEEDS BELOW CRITICAL LEVELS...AND FORECAST SOUNDINGS SHOW
THE HIGHER WINDS ALOFT/GUST POTENTIAL HAPPENING EARLIER IN THE
AFTERNOON...BEFORE THE RH VALUES DROP. CONFIDENCE IN THE WIND/WIND
GUST AND RH CRITERIA BOTH BEING MET FOR 3 HOURS WAS LOW ENOUGH TO
NOT ISSUE A HEADLINE. HOWEVER...IT WILL BE SOMETHING FOR THE DAY
SHIFT CREW TO KEEP A CLOSE EYE ON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT/FIRE WEATHER...ADO
LONG/AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1133 PM CDT FRI JUL 27 2012
.DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS A BROAD UPPER LEVEL
RIDGE HOLDING STEADY OVER THE CENTRAL AND NORTHERN HIGH PLAINS
WITH PLENTY OF SHORTWAVES ROTATING AROUND THE PERIPHERY. THE LATEST
NAM AND SREF INDICATE THAT UPPER LEVEL DIVERGENCE WILL INCREASE
ACROSS WESTERN AND SOUTH CENTRAL NORTH DAKOTA THE REST OF THE
NIGHT AS AN EJECTING SHORTWAVE NOW IN SOUTH CENTRAL MONTANA
APPROACHES. HENCE A CHANCE FOR SHOWERS/THUNDERSTORMS CONTINUE FOR
WESTERN AND SOUTH CENTRAL NORTH DAKOTA. THE LATEST HRRR WHICH HAS
BEEN OVERDOING THE CURRENT PRECIPITATION IS COMING MORE IN LINE
WITH WHAT IS ACTUALLY OCCURRING AND IT DEVELOPS PRECIPITATION IN
ROUGHLY THE SAME AREA AS THE NAM/SREF OVERNIGHT. ONLY MADE MINOR
CHANGES TO THE POP COVERAGE PER NAM/SREF/HRRR AS THE MAIN
FORECAST ALREADY HAD A GOOD HANDLE ON THE SCENARIO.
&&
.AVIATION...A STATIONARY FRONTAL BOUNDARY ACROSS EASTERN MONTANA
INTO WESTERN SOUTH DAKOTA...IS FORECAST TO MOVE INTO WESTERN NORTH
DAKOTA BY SATURDAY EVENING. THE FRONT WILL BE THE FOCUS FOR
SHOWERS AND SCATTERED THUNDERSTORMS ACROSS WESTERN AND SOUTHERN
NORTH DAKOTA. SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS WEST AND
SOUTHERN NORTH DAKOTA AFTER 09Z...HOWEVER TO UNCERTAIN AS TO
TIMING TO MENTION IN THE TAFS AT THIS TIME.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
259 AM CDT SAT JUL 28 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
259 AM CDT SAT JUL 28 2012
THE MAIN FOCUS THROUGH THE WEEKEND AND EARLY NEXT WEEK IS WITH THE
PRECIPITATION CHANCES AS A PAIR OF STORM SYSTEMS MOVE THROUGH THE
REGION.
THE CORE OF A SURFACE RIDGE OF HIGH PRESSURE CONTINUES TO DRIFT TO
THE EAST WITH A WEAK SURFACE TROUGH RUNNING NORTHWEST ALONG THE
MISSISSIPPI RIVER. SKIES HAVE MAINLY CLEARED OUT WITH SOME MID
LEVEL BASED CU LINGERING ALONG THE SURFACE TROUGH AND HIGH LEVEL
CLOUD COVER STARTING TO MOVE IN FROM THE WEST OFF OF CONVECTION IN
THE DAKOTAS. SOME SHALLOW GROUND/VALLEY FOG HAS FORMED THIS
MORNING BUT SURFACE DEW POINT DEPRESSIONS REMAIN A FEW DEGREES OFF
ELSEWHERE AND HAS NOT ALLOWED FOR WIDESPREAD FOG FORMATION.
THE DAKOTAS CONVECTION HAS FORMED AS A MID LEVEL SHORT WAVE TROUGH
ROUNDS THE NORTHERN PERIPHERY OF THE FLAT MID LEVEL RIDGE IN THE
SOUTHERN PLAINS/ROCKIES. THIS CONVECTION HAS ALSO BEEN FUELED BY
850MB WARM AIR ADVECTION...ISENTROPIC LIFT ON THE 315K SURFACE AND
A CORRIDOR OF 2000 J/KG 0-3KM MUCAPE THAT NOSES UP INTO THE
CONVECTION. THESE FEATURES WILL BE THE MAIN FORCING FEATURES FOR
OUR REGION AS THE SYSTEM MOVES EAST THIS WEEKEND.
THE MID LEVEL SHORT WAVE TROUGH DIVES SOUTHEAST THROUGH THE
NORTHWEST FLOW TODAY WITH THE LOW LEVEL FORCING SLOWLY DRIFTING
EAST INTO IOWA. THIS SHOULD TAKE THE ONGOING CONVECTION IN
SOUTHERN SOUTH DAKOTA TO THE SOUTHEAST TOWARD CENTRAL IOWA TODAY
AS A SURFACE LOW MOVES ACROSS NEBRASKA. THROUGH 00Z...IT APPEARS
THAT MUCH OF THE LOW LEVEL FORCING FROM THE 850MB WAA AND
ISENTROPIC LIFT STAYS MAINLY IN IOWA AND SOUTHERN MINNESOTA...SO
HAVE KEPT THE CHANCES TO THIS REGION. LITTLE TO NO 0-3KM MUCAPE
COMES IN DURING THIS TIME FRAME...SO HAVE KEPT ANY THUNDER MENTION
ISOLATED. THESE TRENDS CONTINUE INTO THE OVERNIGHT HOURS AS THE
FORCING AIMS TO THE EAST A BIT MORE CLOSER TOWARD THE MISSISSIPPI
RIVER WITH MUCAPE REMAINING LOW AT LESS THAN 500 J/KG. THE NOSE OF
THE 925-850MB MOISTURE TRANSPORT PROPAGATES SOUTHEAST ACROSS
CENTRAL IOWA TONIGHT AND DOES NOT PUSH TOO FAR NORTHEAST INTO THE
FORECAST AREA GOING INTO SUNDAY. WITH THE BEST FORCING REMAINING
IN SOUTHERN MINNESOTA/IOWA TODAY INTO TOMORROW...HAVE KEPT THE
BEST CHANCES FOR PRECIPITATION ACROSS THIS REGION. MUCH LESS
CONFIDENT IN THE CHANCES GOING EAST OF THE MISSISSIPPI AS THE
FORCING BECOMES MORE BROAD AND THERE BEING MUCH LESS INSTABILITY
TO WORK WITH. TEMPERATURES TODAY WILL BE DEPENDENT ON HOW MUCH
CLOUD COVER MOVES IN AND HOW FAST. WITH HIGH LEVEL CLOUD COVER
TO THE RIVER BY EARLY AFTERNOON...LOCATIONS WEST OF IT WILL SEE
LOWER MAX TEMPERATURES IN THE UPPER 70S TODAY.
SOME DIFFERENCES ARISE BETWEEN THE 28.00Z NAM/GEM AND 28.00Z GFS
FOR SUNDAY WITH THE NAM/GEM TAKING THE PRECIPITATION TO THE
SOUTHEAST TOWARD WESTERN ILLINOIS ALONG THE NOSE OF THE LOW LEVEL
MOISTURE TRANSPORT WHILE THE GFS LINGERS PRECIPITATION AROUND
THROUGH THE DAY WITH A DEEPER 850MB LOW SITTING OVER THE REGION.
HAVE TRENDED SUNDAY MORE ON THE DRY SIDE...BUT HAVE LEFT THE
CHANCES GOING IN NORTHEAST IOWA/SOUTHWEST WISCONSIN FOR ANY
LEFTOVER SHOWERS THAT COULD BE LINGERING FROM THE SOUTHERN SYSTEM.
A SURFACE RIDGE AXIS WILL THEN HELP TO DRY THINGS OUT SUNDAY NIGHT
AS THE NEXT SYSTEM TRACKS ACROSS THE NORTHERN PLAINS/SOUTHERN
CANADA. THIS SYSTEM WILL BRING A SURFACE COLD FRONT THROUGH THE
REGION MONDAY INTO MONDAY NIGHT. SOME CONSIDERABLE TIMING
DIFFERENCES ON WHEN THE FRONT MAKES IT IN SHOW UP BETWEEN THE
28.00Z NAM/GFS/ECMWF WITH THE NAM BEING THE FASTEST IN BRINGING IT
THROUGH DURING THE AFTERNOON MONDAY. THE NAM IS ALSO ON THE HIGH
SIDE WITH TEMPERATURE ADVECTION AND IS THE WARMEST WITH ITS HIGHS
FOR MONDAY IN THE UPPER 90S. MONDAY DOES APPEAR TO BE THE WARMEST
DAY OF THE NEXT WEEK...THOUGH LOW 90S SEEM TO BE MORE LIKELY THAN
NEAR RECORD HIGHS. WHILE INSTABILITY DOES BUILD ALONG/AHEAD OF
THE FRONT...THE BETTER LOW TO MID LEVEL LIFT STAYS NORTH CLOSER TO
THE MID LEVEL TROUGH TO THE NORTH. THEREFORE...HAVE GONE A LITTLE
MORE CONSERVATIVE ON THE PRECIPITATION CHANCES MONDAY/MONDAY NIGHT
WITH THE BEST CHANCES IN NORTH CENTRAL WISCONSIN.
.LONG TERM...TUESDAY THROUGH FRIDAY
259 AM CDT SAT JUL 28 2012
WITH THE COLD FRONT CLEAR OF THE REGION ON TUESDAY...HIGH PRESSURE
WILL SETTLE IN ACROSS THE UPPER MISSISSIPPI RIVER VALLEY REGION
AND PROVIDE A DRY TUESDAY AND TUESDAY NIGHT. THE UPPER LEVEL RIDGE
REMAINS IN PLACE THROUGHOUT THE WEEK ALONG THE WESTERN
PLAINS/ROCKIES WITH WEAK TROUGHING ALONG THE EAST COAST. THE NEXT
MID LEVEL SHORT WAVE TROUGH APPEARS TO EJECT OUT OF THE CANADIAN
ROCKIES MID WEEK. THIS TROUGH AND SURFACE COLD FRONT SHOULD MOVE
INTO THE REGION LATE WEDNESDAY AFTERNOON AND EVENING AND BRING THE
NEXT CHANCE FOR PRECIPITATION ALONG WITH IT. NOT MUCH IN THE WAY
OF LOW LEVEL WARM AIR ADVECTION THROUGH THE WEEK...SO AM EXPECTING
MAINLY SEASONAL OR SLIGHTLY WARMER THAN NORMAL TEMPERATURES
THROUGH NEXT WEEK.
&&
.AVIATION...THROUGH 06Z SUNDAY
1150 PM CDT FRI JUL 27 2012
MAIN NEAR TERM CONCERN CONTINUES ON FOG POTENTIAL. 04Z
OBSERVATIONS SHOWS 6 DEGREE TEMPERATURE/DEW POINT SPREAD AT KLSE
AND 7 DEGREES AT KRST. HIGH PRESSURE WAS CENTERED OVER MINNESOTA
AND NORTHERN WISCONSIN AND WILL SETTLE OVER THE AREA. CLOUDS HAVE
CLEARED AT BOTH TAF SITES AND BOTH THE NAM AND RAP SOUNDINGS SHOW
DEEP LAYER LIGHT WINDS. 28.03Z RAP CONTINUES TO SHOW A 2 TO 3
DEGREE CELSIUS TEMPERATURE/DEW POINT SPREAD LATE TONIGHT...WHILE
NAM IS MORE SATURATED. WITH THESE FAVORABLE CONDITIONS DID
CONTINUE THE MENTION OF FOG AT BOTH SITES...BUT NOT QUITE AS LOW
AT KRST. VFR CONDITIONS THEN EXPECTED THROUGH THE REMAINDER OF THE
FORECAST PERIOD. DID ADD MENTION OF VCSH AT KRST AFTER 03Z
SUNDAY AHEAD OF THE NEXT WAVE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
259 AM CDT SAT JUL 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1108 PM CDT FRI JUL 27 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.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...POSSIBLITY FOR PATCHY/AREAS OF DENSE FOG EXISTS FOR
THE OVERNIGHT PERIOD...PARTICULARLY ACROSS NORTH CENTRAL
WISCONSIN. ALSO COULD BE SOME PATCHY DENSE FOG OVER PARTS OF THE
FOX VALLEY...PARTICULARLY IN AREAS WHERE SUBSTANTIAL RAINFALL HAS
FALLEN OVER THE PAST 48 HOURS.
SCT-BKN VFR CIGS EXPECTED TO DEVELOP AROUND MID-DAY SATURDAY AS
RESIDUAL BOUNDARY LAYER MOISTURE FROM RECENT RAINS WILL LINGER.
WINDS EXPECTED TO BE LIGHT AND VARIABLE THROUGH MID-DAY AS HIGH
PRESSURE DRIFTS ACROSS THE AREA. THERE IS SOME INDICATION FROM
HIGHER RESOLUTION MODELS OF ONSHORE SOUTHEAST FLOW DEVLOPING
AND PERHAPS PENETRATING AS FAR WEST AS GRB...ATW AND OSH BY LATE
AFTERNOON.
EB
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
415 AM MDT SAT JUL 28 2012
.SHORT TERM...
(TODAY AND TONIGHT)
CURRENTLY...THE UPPER RIDGE AXIS REMAINED OVER WESTERN KS EARLY THIS
MORNING WITH THE VERY EVIDENT MONSOON PLUME BEING DRAWN UP ACROSS
THE 4 CORNERS AND INTO CO...AS PER RAP H5 ANALYSIS AND IR SATELLITE
IMAGERY. SFC OBS INDICATED THAT TEMPS HAD DROPPED INTO THE UPPER 50S
TO MID 60S FOR MOST PLAINS LOCATIONS AND DOWN TO AROUND 50F FOR THE
HIGH VALLEYS AS OF 330 AM. DEWPOINT TEMPS WERE FAIRLY UNIFORM FOR
THE CWA...IN THE MID 40S TO LOWER 50S.
TODAY AND TONIGHT...THE WEATHER TREND FOR TODAY LOOKS LIKE IT WILL
BE VERY SIMILAR TO FRIDAY...MINUS THE SPARK PROVIDED BY THE UPPER
DISTURBANCE THAT ROLLED ACROSS THE ROCKIES. PRECIPITABLE WATER
REMAINS AT OR SLIGHTLY ABOVE NORM...BUT UPPER AIR SOUNDINGS POINT
TO SOMEWHAT DRY LOW LEVELS. THE RIDGE AXIS REMAINING NEAR THE
CO/KS BORDER WILL IMPART A GRADUAL N-NE MOVEMENT FOR ANY STORMS
THAT DO DEVELOP OVER THE HIGHER TERRAIN THIS AFTN. MODELS ARE
HINTING AT A SFC BOUNDARY LURKING ALONG THE PALMER DVD THIS
AFTN...AND WHERE THIS BOUNDARY STALLS WILL BE A FOCUS AREA FOR
CONVECTION. DECIDED TO HOLD ONTO THE ONGOING FORECAST THAT KEEPS
THIS BOUNDARY PRIMARILY NORTH OF THE PALMER DVD...WITH CONVECTION
FIRING OVER MONUMENT HILL THIS AFTN BUT NOT ALONG KIOWA COUNTY.
EXPECT ANOTHER HOT DAY TODAY WITH MAX TEMPS RIGHT AROUND 100 F FOR
THE PLAINS...AND IN THE 80S FOR THE HIGH VALLEYS.
THE MAIN FORECAST CONCERN CONTINUES TO BE THE FLASH FLOOD POTENTIAL
FOR THE WALDO CANYON BURN SCAR THIS AFTN AND EVE. INDIVIDUAL STORMS
HAVE SHOWN SOME SPOTTY HIGHER RAINFALL RATES OVER THE PAST WEEK AND
LUCKILY HAVE SIDE-STEPPED THE BURN SCAR FOR THE MOST PART...BUT WITH
LITTLE CHANGE IN THE OVERALL PATTERN LOCALLY HEAVY RAINFALL REMAINS
A THREAT. MOORE
.LONG TERM...
(SUNDAY THROUGH SATURDAY)
CONCERNS ARE COVERAGE OF SLOW MOVING THUNDERSTORMS THROUGH THE
WEEK...ESPECIALLY MONDAY.
SUNDAY THROUGH MONDAY...UPPER RIDGE CENTERED OVER WESTERN US WILL
PROVIDE WEAK WEST TO SOUTHWEST FLOW ALOFT. A SHORTWAVE MOVING
SOUTHEAST THROUGH THE GREAT PLAINS WILL BRING A COUPLE OF
BOUNDARIES INTO EASTERN COLORADO. THE STRONGER PUSH OF
COOLER...AND SLIGHTLY MOISTER LOW LEVEL AIR WILL LIKELY OCCUR
SUNDAY NIGHT WITH EASTERLY UPSLOPE FLOW DEVELOPING ACROSS THE
PLAINS THROUGH THE DAY ON MONDAY. BUT...MONSOONAL MOISTURE
FORECAST TO MOVE MAINLY WEST AND NORTH OF THE CWA. ISOLATED TO
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL
OCCUR...WITH BEST COVERAGE REMAINING OVER AND ADJACENT TO THE
MOUNTAINS. WEAK FLOW ALOFT WILL BRING THE THREAT FOR LOCALLY HEAVY
RAINFALL AND THE POSSIBILITY OF FLASH FLOODING...ESPECIALLY IF
CELLS DEVELOP OVER THE BURN SCARS...INCLUDING THE WALDO CANYON
BURN SCAR. MID LEVEL TEMPERATURES WILL BE A BIT LOWER ON MONDAY
ACROSS THE PLAINS...BUT STILL...TEMPERATURES WILL BE ABOVE
SEASONAL AVERAGES BOTH DAYS.
TUESDAY-FRIDAY...UPPER LEVEL RIDGE FORECAST TO PERSIST JUST SOUTH
OF THE AREA...WITH RESULTANT WEAK WESTERLY FLOW ALOFT. MODELS
ALSO NOT TOO HEAVY HANDED WITH THE MONSOON MOISTURE. THERE WILL BE
ENOUGH MOISTURE FOR DAILY ISOLATED TO SCATTERED COVERAGE OF
PRECIPITATION WITH TEMPERATURES RISING A BIT FROM EARLY WEEKS
LEVELS. -TLM-
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED FOR THE THREE MAIN TAF SITES OF
KCOS...KPUB AND KALS FOR THE NEXT 24 HRS. HOWEVER...ISOLATED
CONVECTION WILL AFFECT KCOS AND KALS AFTER 18Z AND LASTING THROUGH
03Z...WITH THE MAIN THREAT BEING GUSTY WINDS OF 35-40 KTS. STORMS
WILL BE MORE SCATTERED OVER THE HIGHER TERRAIN...LINGERING THE
LONGEST OVER THE CONTDVD. THE STEERING FLOW IS FORECAST TO REMAIN
GENERALLY LIGHT AND FROM THE S-SW...SO ANY STORMS THAT FORM OVER THE
MTS WILL SLOWLY MOVE TO THE N-NE. MOORE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27/13
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT SAT JUL 28 2012
.DISCUSSION...
ISSUED 1045 AM CDT SAT JUL 28 2012
WILL BE UPDATING THE FORECAST TODAY FOR MORE CLOUD COVER TODAY AND
MAY NEED TO ADD SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS LATE
THIS AFTERNOON NW OF THE IL RIVER. OTHERWISE REST OF FORECAST
LOOKS OK WITH HIGHS RANGING FROM THE MID 80S FROM LINCOLN NW TO
THE LOWER 90S IN SE IL. A WEAK/SMALL MCS OVER CENTRAL/NW IA INTO
SE SD AND SW MN IS SPREADING MID/HIGH CLOUDS QUICKLY SE INTO
CENTRAL IL THIS MORNING. ALSO HAVE SCATTERED CUMULUS CLOUDS
DEVELOPING BY LATE MORNING ACROSS AREAS EAST OF I-55 WITH BROKEN
CEILINGS OVER PARTS OF CENTRAL INDIANA. MODELS WEAKEN SHOWERS AND
THUNDERSTORMS OVER CENTRAL AND NW IA AS THEY TRACK SE INTO NW IL
THIS AFTERNOON. NAM KEEPS IT DRY OVER CWA THROUGH TONIGHT BUT HRRR
BRINGS PATCHES OF QPF INTO AREAS ALONG AND NORTH OF I-74 LATER
THIS AFTERNOON AND EVENING. WITH SEVERE TO EXTREME DROUGHT OVER
CENTRAL IL...THINK HRRR IS OVERDOING QPF BUT THINK NAM MAY BE TOO
DRY INTO TONIGHT SO WILL USE A BLEND THERE.
KH
&&
.AVIATION...
ISSUED 627 AM CDT SAT JUL 28 2012
FAIRLY QUIET WEATHER IS IN STORE FOR TODAY... WITH VFR CONDITIONS
EXPECTED THROUGH THIS TAF CYCLE. HIGH CLOUDS WILL SPREAD ACROSS THE
TERMINALS LATER THIS AFTERNOON AND PERSIST THROUGH THE OVERNIGHT.
MODELS HINT THAT SOME SHOWERS COULD DEVELOP TOWARDS THE END OF THE
PERIOD AT PIA/SPI AS AN UPPER LEVEL DISTURBANCE DROPS SOUTHEAST INTO
THE AREA...HOWEVER CONFIDENCE IS TOO LOW IN THIS OCCURRING BEFORE
12Z SO WILL LEAVE OUT MENTION FOR NOW. WINDS WILL MOSTLY BE OUT THE
NORTH/NORTHEAST TODAY...AND THEN GRADUALLY VEER TO THE EAST LATE
TONIGHT. SPEEDS WILL BE 10 KTS OR LESS.
ECT/SMITH
&&
.PREV DISCUSSION...
ISSUED 242 AM CDT SAT JUL 28 2012
LATEST SFC ANALYSIS INDICATED HIGH PRESSURE OVER THE UPPER
MIDWEST. THIS PROVIDED LIGHT NORTHERLY WINDS AND SLIGHTLY
COOLER/LESS HUMID AIR. ALOFT...NORTHWEST MID LEVEL FLOW PREVAILED
FOR MUCH OF THE MIDWEST...BETWEEN AN EASTERN GREAT LAKES TROUGH
AND STRONG CENTRAL PLAINS RIDGING. MAIN FORECAST ISSUE CONTINUES TO
BE TRYING TO PIN DOWN PRECIP CHANCES IN NORTHWEST FLOW...AS OUR
AREA LOOKS TO BE ON THE EDGE OF THE HEAT DOME FOR MUCH OF THE FORECAST.
SHORT TERM...TODAY THROUGH MONDAY
SURFACE HIGH DRIFTS SOUTHEAST THROUGH THE EASTERN GREAT LAKES THIS
WEEKEND. THIS WILL PROVIDE A NORTH/EAST WIND FLOW TODAY WHICH
KEEPS TEMPERATURES NEAR TO SLIGHTLY ABOVE NORMAL. SOUTHERLY WINDS
ON THE BACK SIDE OF THE HIGH WILL WARM TEMPS A FEW MORE DEGREES
SUNDAY. FOR RAIN CHANCES... TO OUR WEST...MID LEVEL THERMAL
GRADIENT...LOW-LEVEL JET...AND SHORTWAVES TOPPING THE UPPER LEVEL
RIDGE WILL PRODUCE NIGHTLY MCS ACTIVITY. THE FIRST OF THESE WAVES
CURRENTLY OVER THE SD/NEB BORDER IS FORECAST TO SPREAD
THUNDERSTORMS INTO IOWA TODAY BEFORE DISSIPATING. MAIN IMPACT
LOCALLY WOULD BE AN INCREASE MID/HIGH LEVEL CLOUDS. NEXT
DISTURBANCE IS PROGGED TO DEVELOP STORMS OVER CENTRAL IOWA AFTER
06Z TONIGHT AND DROP SOUTHEAST ALONG MID LEVEL THERMAL/MOISTURE
GRADIENT. CONDITIONS ARE LESS FAVORABLE FOR THIS ACTIVITY TO HOLD
TOGETHER AS IS SHIFTS EAST OF THE MISSISSIPPI RIVER SUNDAY
MORNING. HAVE LIMITED POPS TO LOW CHANCE IN THE WEST...WITH SLIGHT
CHANCES FARTHER EAST. A SOMEWHAT BETTER SETUP FOR THUNDERSTORMS
SETS UP OVER THE AREA SUNDAY NIGHT INTO MONDAY WITH A MORE
FAVORABLE LOW-LEVEL JET ORIENTATION AND THETA-E GRADIENT...HOWEVER
FORCING IS NOT THAT IMPRESSIVE AND AGAIN LIMITED POPS TO LOW
CHANCE.
LONG TERM...TUESDAY THROUGH FRIDAY
LITTLE CHANGE IN THE OVERALL SYNOPTIC PATTERN IS SHOWN BY
TONIGHTS 00Z MEDIUM RANGE MODELS. A GENERAL NORTHWEST MID-LEVEL
FLOW CONTINUES AS THE STRONG SOUTHERN PLAINS RIDGE PERSISTS.
ACCEPTED ECMWF 850 MB TEMPS WARM TO +20C OR GREATER WHICH WOULD
SUPPORT ANOTHER STRETCH OF WARM WEATHER WITH HIGHS IN THE 90S AND
LOWS IN THE 70S. HOWEVER...THIS PATTERN DOES NOT APPEAR NEARLY AS
HOT AS LAST WEEK. PRECIP CHANCES WILL BE HIGHLY DEPENDENT ON
SHORTWAVES MOVING THROUGH IN FASTER FLOW ON THE PERIPHERY OF THE
HOT/CAPPED AIRMASS CENTERED TO OUR WEST. THIS WILL BE REFINED IN
LATER FORECASTS BUT GIVEN EXTREME DROUGHT HAVE KEPT POPS TO SLIGHT
CHANCE OR LESS.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
700 AM EDT SAT JUL 28 2012
.AVIATION... /12 UTC TAFS/
LITTLE CHANGE WRT LATEST NRN IN TAFS. MORE SOLID MVFR STRATOCU DECK
INTO NERN IN ATTM...WITHIN HEART OF LLVL THERMAL TROF...WITH WRN
FRINGE INVOF KSBN. STILL SOME MVFR CU REGEN PSBL THIS AM FOR BRIEF
MVFR CIGS AT KSBN WITH INCRSD TURBULENT MIXING. SOME CONCERN LATE IN
FCST PD FOR SHALLOW/PATCHY BR FORMATION NEAR SUNRISE...ESPCLY AT
KFWA WITH SLIGHTLY HIR XOVER TEMP.
&&
.SHORT TERM...
TODAY THROUGH SUNDAY NIGHT. BENIGN PATTERN IN SHORT TERM PD. 1021 MB
SFC HIGH ACRS NRN WI TO DROP SLOWLY SEWD INTO LWR GRTLKS BY MON AM.
STATIC MIDLVL REGIME FEATURING STRONG OK/NRN TX RIDGE CENTER WITH
MULTIPLE SHORTWAVES RIDING BROAD WRLIES ACRS NRN PLAINS/SRN
CANADA...THEN TRACKING INTO MEAN ERN STATES TROF. ANTICIPATE FURTHER
EXPANSION WITHIN 925MB THERMAL TROF ACRS SRN MI/NRN IN THIS AM AMID
TURBULENT N-NERLY 10-15KT FLOW PER KDTX VWP AND RAP POINT SNDGS.
RAPID MIXOUT OF CLOUDS COINCIDENT WITH RAPID EROSION OF LOW BASED
SUBSIDENCE INVERSION/RAPID RISING CCL/ENTRAINMENT OF SIG DRIER AIR
ALOFT. SLIGHT DOWNWARD NUDGE IN TEMPS TODAY PER AM CLOUD COVER/DEEP
NRLY FLOW/GUID CLUSTERING/SIMILAR THERMAL REGIME AS SEEN YDAY ACRS
SRN WI. SLIGHT NUDGE TOWARD NAM/ECMWF WRT NEXT MINIMAL TSRA CHCS
ACRS SWRN CWA LATE SUNDAY NIGHT/ERLY MONDAY MORNING. RATHER WEAK
PIECEMEAL ENERGY ACRS WRN/CNTL MT EMANATING FM STRONGER SRN BC
VORTEX TO TRACK INTO CNTL MS VLY LATE DY2. PSBL MCS DVLPG ACRS KS/MO
SUNDAY EVENING WITH EWD MAINTENANCE PER RAMPING NOCTURNAL JETLET
INTO ECNTL MO OVERNIGHT. EWD PUSH OF EML MAY BE LIMITED PER MORE
VEERED FLOW WITH ERN EXTENT AND RELEGATE HIEST CHCS ACRS CNTL
IL/CNTL IN TOWARD DAYBREAK...AND HAVE OMITTED MENTION ACRS NRN CWA
06-12 UTC MON.
&&
.LONG TERM... /MONDAY THROUGH FRIDAY.
IN COORDINATION WITH SHORT TERM PERIOD...HAVE OPTED TO LOWER POPS
MON/MON NGT GIVEN INCREASING SIGNALS FROM ECMWF AND GEFS OF LITTLE
OR NO PRECIP OCCURRING AS WEAK WAVE SET TO MOVE THROUGH LATE SUN
INTO MONDAY WILL BE SERIOUSLY LACKING ANY MSTR OR SIG
LIFT...LIMITING ITS EFFECTS MAINLY TO INCREASE IN MID LEVEL CLOUDS
AND MAYBE SOME LIGHT SHOWERS. SOMEWHAT STRONGER WAVES WILL MOVE
ACROSS THE NORTHERN/CENTRAL GREAT LAKES TUESDAY AND AGAIN THURSDAY.
WITH NW FLOW IN PLACE...MSTR WILL REMAIN CUT OFF WITH THESE SYSTEMS
AS WELL...BUT AT LEAST A BIT MORE IN THE WAY OF DYNAMICS WITH EACH
WAVE TO HANG ONTO CHC/SLGT CHC POPS...MAINLY IN NORTH AND EAST
SECTIONS.
WITH LITTLE CHANGE IN OVERALL FLOW...TEMPERATURES SHOULD REMAIN IN
THE 85 TO 90 DEGREE RANGE MUCH OF THE PERIOD WITH LOWER READING SEEN
WITH PASSAGE OF EACH WAVE AND ASSOCIATED CLOUDS/PRECIP. BY
FRIDAY...SLIGHTLY COOLER AIR MAY ARRIVE BEHIND THE THURSDAY
SYSTEM...BUT WILL ONLY SHAVE A FEW DEGREES OFF HIGHS COMPARED TO THE
REST OF THE WEEK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK THROUGH THIS EVENING FOR INZ003.
MI...RIP CURRENT RISK THROUGH THIS EVENING FOR MIZ077.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MURPHY
LONG TERM...FISHER
AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS JACKSON KY
1121 AM EDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 1121 AM EDT SAT JUL 28 2012
LATEST SATELLITE IMAGERY INDICATES EXTENSIVE CU/SC FIELD WILL AFFECT
THE FORECAST AREA THIS AFTERNOON...WITH PARTLY CLOUDY SKIES. HAVE
UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 954 AM EDT SAT JUL 28 2012
OVERCAST LOW STRATUS ON SATELLITE IMAGERY THIS MORNING IN NORTHERN
PART OF FORECAST AREA AND IN SOUTHERN OH. BASED ON GOES CLOUD
THICKNESS PRODUCT THIS IS THINNING FAIRLY RAPIDLY. WAS AROUND 1200
FEET THICK AT 1215Z AND THINNING TO AROUND 600 FEET AT 1315Z. EXPECT
STRATUS TO CONTINUE TO THIN AND MIX OUT. ILN SOUNDING SHOWS FAIRLY
MOIST CONDITIONS UP TO 7OO MB AND AS LOW STRATUS MIXES OUT EXPECT CU
TO DEVELOP. HAVE MADE ADJUSTMENTS TO SKY COVER FORECAST TO ACCOUNT
FOR MORE CLOUD IN THE NORTH THIS MORNING...AND MORE CLOUD FOR THIS
AFTERNOON AS WELL AS CU FIELD DEVELOPS. SKY COVER HAS ALSO AFFECTED
THE DIURNAL TEMPERATURE RISE AND HAVE SLOWED THE RISE WHERE
CONDITIONS WILL BE MOSTLY CLOUDY THIS MORNING.
KEPT THE SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FAR
SOUTHEAST THIS AFTERNOON. THE 06Z GFS STILL SUPPORTS THIS
IDEA...WHILE THE 06Z NAM WOULD POINT TOWARDS DRY CONDITIONS.
INTERESTINGLY THE HRRR DEVELOPS SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS NEARLY THE ENTIRE FORECAST AREA THIS AFTERNOON. FEEL THIS IS
OVERDONE AND ONLY EXPECT A CU FIELD...NOT SCATTERED PRECIPITATION.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 623 AM EDT SAT JUL 28 2012
FORECAST IS IN PRETTY GOOD SHAPE THIS MORNING WITH SKIES CONTINUING
TO CLEAR OFF. THERE IS SOME PATCHY MORNING FOG IN THE VALLEYS WHICH
WILL BE BURNING OFF SHORTLY AFTER SUNRISE. COLD FRONT IS CONTINUING
TO MAKE STEADY PROGRESS TO THE SOUTH AND EAST. LATEST 06Z NAM KEEPS
ALL THE CONVECTION SOUTHEAST OF THE AREA TODAY...BUT THE HRRR SHOWS
SOME HINTS AT SOME DEVELOPMENT IN THE SOUTHEAST AROUND MIDDAY.
THUS...GOING TO HANG ONTO THE SMALL CHANCE FOR SHOWERS AND
THUNDERSTORMS FOR THE TIME BEING. IT IS POSSIBLE EVERYTHING ENDS UP
FURTHER SOUTHEAST AND THE AREA STAYS COMPLETELY DRY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 308 AM EDT SAT JUL 28 2012
COLD FRONT IS QUICKLY DROPPING SOUTHEAST...VIRTUALLY ALIGNED WITH THE
OHIO RIVER PRESENTLY. COMPLEX OF SHOWERS AND STORMS CONTINUES TO ROLL
ACROSS AREAS NEAR THE TENNESSEE BORDER. BASED ON RADAR TRENDS...THIS
ACTIVITY SHOULD CONTINUE TO DIMINISH AND EXIT OVER THE NEXT
HOUR...LEAVING BEHIND DRY CONDITIONS FOR THE REMAINDER OF THE
MORNING. COLD FRONT WILL ROCKET SOUTHEAST THIS MORNING...REACHING THE
VIRGINIA/KENTUCKY BORDER BY MID MORNING. WITH MOISTURE POOLING AHEAD
OF THE FRONT...A FEW SHOWERS OR STORMS COULD DEVELOP IN THE VICINITY
OF THE VIRGINIA BORDER BY MIDDAY INTO THE EARLY AFTERNOON. THIS
SHOULD ONLY IMPACT A SLIVER OF EASTERN KENTUCKY. THE REST OF THE AREA
WILL REMAIN DRY TODAY. THERE IS MARGINAL WIND SHEAR PRESENT...BUT
SEVERE THREAT WILL LIKELY BE CONFINED TO AREAS FURTHER SOUTHEAST OF
KENTUCKY.
HIGH PRESSURE WILL CONTINUE TO DEVELOP OVER THE REGION TODAY THROUGH
TONIGHT...KEEPING QUIET WEATHER AROUND THROUGH THE REMAINDER OF THE
WEEKEND.
A VERY PLEASANT WEEKEND IS ON TAP AS SLIGHTLY COOLER AND A LESS HUMID
AIRMASS SPREAD INTO EASTERN KENTUCKY HIGHS TODAY AND SUNDAY WILL TOP
OUT IN THE MID 80S WITH LOWS IN THE MID 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 445 AM EDT SAT JUL 28 2012
THE MODELS ARE IN DECENT AGREEMENT WITH THE GENERAL PATTERN ALOFT
THROUGH THE EXTENDED PORTION OF THE FORECAST. A SEMI-PERSISTENT TROUGH
WILL HOLD IN PLACE JUST TO THE NORTHEAST OF THE REGION THROUGH THE
MIDDLE OF NEXT WEEK. THIS WILL PROMOTE OCCASIONAL SHORTWAVES TO DROP
INTO THE OHIO VALLY ON NORTHWEST FLOW. A KEY ONE LOOKS TO MOVE
THROUGH LATE MONDAY. TOWARD THE END OF THE UPCOMING WORK WEEK THE
MODELS START TO DEVIATE FROM EACH OTHER WITH THE LATEST ECMWF PUSHING
THE WESTERN RIDGE FURTHER EAST AND FLATTENING OUT THE PATTERN
LOCALLY WHEN COMPARED TO THE GFS. ACCORDINGLY...PREFER A BLENDED
SOLUTION WHEN THE MODELS ARE CLOSE...BUT LEAN MORE TOWARD THE ECMWF
WHEN THEY START TO DEVIATE. DID HONOR THE SHORTWAVE THAT THE NAM12
AND THE 00Z ECMWF BRING DOWN INTO THE AREA MONDAY NIGHT AS A
POTENTIAL MCS...OTHERWISE PREFER AN EVEN MIX OF THE GFS AND ECMWF
FOR WEATHER SPECIFICS THROUGH MIDWEEK...LEANING MORE TOWARD THE
LATTER BY THE END OF THE WEEK. ALSO INCLUDED A GENEROUS DIURNAL
CYCLE TO THE POP PATTERN AND MAGNITUDE...THOUGH...AS THE PAST SEVERAL
NIGHTS HAVE SHOWN...THE CONVECTION HAS BEEN ABLE TO THRIVE WELL PAST
PEAK HEATING...IN OUR AREA.
SENSIBLE WEATHER WILL FEATURE HIGH PRESSURE HOLDING ON FOR A MOSTLY
DRY DAY ON MONDAY BEFORE A WARM FRONT APPROACHES FROM THE WEST
POSSIBLY YIELDING SOME LATE DAY STORMS. THESE STORM CHANCES WILL
CONTINUE THROUGH THE NIGHT AS A SHOT OF MID LEVEL ENERGY LOOKS TO
DIVE THROUGH THE STATE AFTER DARK IN THE NAM12...WITH CONSIDERABLE
SUPPORT FROM THE LATEST ECMWF. OTHERWISE...WITH A WEAK PRESSURE
FIELD THROUGHOUT THE REGION...NORTHWEST FLOW ALOFT...AND A HUMID
ENVIRONMENT...EXPECT THE DIURNAL INSTABILITY CYCLE TO DRIVE THE
CONVECTIVE CHANCES INTO THE END OF THE WEEK WITH PERHAPS ANOTHER
BOUNDARY MOVING INTO THE CWA LATE IN THE PERIOD IN RESPONSE TO
CHANGES ALOFT. TEMPERATURES WILL BE SEASONABLY WARM THROUGH THE
EXTENDED WITH PLENTY OF HUMIDITY KEEPING THE LOWS FAIRLY HIGH AND
CONDITIONS MUGGY EACH NIGHT.
THE CR EXTENDED GRID PACKAGE CAME IN REASONABLE FOR THE PATTERN...
THOUGH DID MAKE ADJUSTMENTS TO THE DIURNAL/TEMPORAL PATTERN OF
MAXIMUM AND MINIMUM POPS THROUGH THE PERIOD. MADE ONLY MINOR TWEAKS
TO LOW TEMPERATURES EACH NIGHT AS THE TERRAIN EFFECTS WILL BE RATHER
LIMITED GIVEN THE STILL MOIST ENVIRONMENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 623 AM EDT SAT JUL 28 2012
AFTER SOME PATCHY MORNING VALLEY FOG...VFR CONDITIONS WILL TAKE HOLD
ACROSS THE AREA BY MID MORNING AND CONTINUING THROUGH THIS EVENING.
WE WILL LIKELY SEE MORE PATCHY VALLEY FOG TONIGHT AS CLEAR SKIES
DOMINATE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
954 AM EDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 954 AM EDT SAT JUL 28 2012
OVERCAST LOW STRATUS ON SATELLITE IMAGERY THIS MORNING IN NORTHERN
PART OF FORECAST AREA AND IN SOUTHERN OH. BASED ON GOES CLOUD
THICKNESS PRODUCT THIS IS THINNING FAIRLY RAPIDLY. WAS AROUND 1200
FEET THICK AT 1215Z AND THINNING TO AROUND 600 FEET AT 1315Z. EXPECT
STRATUS TO CONTINUE TO THIN AND MIX OUT. ILN SOUNDING SHOWS FAIRLY
MOIST CONDITIONS UP TO 7OO MB AND AS LOW STRATUS MIXES OUT EXPECT CU
TO DEVELOP. HAVE MADE ADJUSTMENTS TO SKY COVER FORECAST TO ACCOUNT
FOR MORE CLOUD IN THE NORTH THIS MORNING...AND MORE CLOUD FOR THIS
AFTERNOON AS WELL AS CU FIELD DEVELOPS. SKY COVER HAS ALSO AFFECTED
THE DIURNAL TEMPERATURE RISE AND HAVE SLOWED THE RISE WHERE
CONDITIONS WILL BE MOSTLY CLOUDY THIS MORNING.
KEPT THE SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FAR
SOUTHEAST THIS AFTERNOON. THE 06Z GFS STILL SUPPORTS THIS
IDEA...WHILE THE 06Z NAM WOULD POINT TOWARDS DRY CONDITIONS.
INTERESTINGLY THE HRRR DEVELOPS SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS NEARLY THE ENTIRE FORECAST AREA THIS AFTERNOON. FEEL THIS IS
OVERDONE AND ONLY EXPECT A CU FIELD...NOT SCATTERED PRECIPITATION.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 623 AM EDT SAT JUL 28 2012
FORECAST IS IN PRETTY GOOD SHAPE THIS MORNING WITH SKIES CONTINUING
TO CLEAR OFF. THERE IS SOME PATCHY MORNING FOG IN THE VALLEYS WHICH
WILL BE BURNING OFF SHORTLY AFTER SUNRISE. COLD FRONT IS CONTINUING
TO MAKE STEADY PROGRESS TO THE SOUTH AND EAST. LATEST 06Z NAM KEEPS
ALL THE CONVECTION SOUTHEAST OF THE AREA TODAY...BUT THE HRRR SHOWS
SOME HINTS AT SOME DEVELOPMENT IN THE SOUTHEAST AROUND MIDDAY.
THUS...GOING TO HANG ONTO THE SMALL CHANCE FOR SHOWERS AND
THUNDERSTORMS FOR THE TIME BEING. IT IS POSSIBLE EVERYTHING ENDS UP
FURTHER SOUTHEAST AND THE AREA STAYS COMPLETELY DRY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 308 AM EDT SAT JUL 28 2012
COLD FRONT IS QUICKLY DROPPING SOUTHEAST...VIRTUALLY ALIGNED WITH THE
OHIO RIVER PRESENTLY. COMPLEX OF SHOWERS AND STORMS CONTINUES TO ROLL
ACROSS AREAS NEAR THE TENNESSEE BORDER. BASED ON RADAR TRENDS...THIS
ACTIVITY SHOULD CONTINUE TO DIMINISH AND EXIT OVER THE NEXT
HOUR...LEAVING BEHIND DRY CONDITIONS FOR THE REMAINDER OF THE
MORNING. COLD FRONT WILL ROCKET SOUTHEAST THIS MORNING...REACHING THE
VIRGINIA/KENTUCKY BORDER BY MID MORNING. WITH MOISTURE POOLING AHEAD
OF THE FRONT...A FEW SHOWERS OR STORMS COULD DEVELOP IN THE VICINITY
OF THE VIRGINIA BORDER BY MIDDAY INTO THE EARLY AFTERNOON. THIS
SHOULD ONLY IMPACT A SLIVER OF EASTERN KENTUCKY. THE REST OF THE AREA
WILL REMAIN DRY TODAY. THERE IS MARGINAL WIND SHEAR PRESENT...BUT
SEVERE THREAT WILL LIKELY BE CONFINED TO AREAS FURTHER SOUTHEAST OF
KENTUCKY.
HIGH PRESSURE WILL CONTINUE TO DEVELOP OVER THE REGION TODAY THROUGH
TONIGHT...KEEPING QUIET WEATHER AROUND THROUGH THE REMAINDER OF THE
WEEKEND.
A VERY PLEASANT WEEKEND IS ON TAP AS SLIGHTLY COOLER AND A LESS HUMID
AIRMASS SPREAD INTO EASTERN KENTUCKY HIGHS TODAY AND SUNDAY WILL TOP
OUT IN THE MID 80S WITH LOWS IN THE MID 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 445 AM EDT SAT JUL 28 2012
THE MODELS ARE IN DECENT AGREEMENT WITH THE GENERAL PATTERN ALOFT
THROUGH THE EXTENDED PORTION OF THE FORECAST. A SEMI-PERSISTENT TROUGH
WILL HOLD IN PLACE JUST TO THE NORTHEAST OF THE REGION THROUGH THE
MIDDLE OF NEXT WEEK. THIS WILL PROMOTE OCCASIONAL SHORTWAVES TO DROP
INTO THE OHIO VALLY ON NORTHWEST FLOW. A KEY ONE LOOKS TO MOVE
THROUGH LATE MONDAY. TOWARD THE END OF THE UPCOMING WORK WEEK THE
MODELS START TO DEVIATE FROM EACH OTHER WITH THE LATEST ECMWF PUSHING
THE WESTERN RIDGE FURTHER EAST AND FLATTENING OUT THE PATTERN
LOCALLY WHEN COMPARED TO THE GFS. ACCORDINGLY...PREFER A BLENDED
SOLUTION WHEN THE MODELS ARE CLOSE...BUT LEAN MORE TOWARD THE ECMWF
WHEN THEY START TO DEVIATE. DID HONOR THE SHORTWAVE THAT THE NAM12
AND THE 00Z ECMWF BRING DOWN INTO THE AREA MONDAY NIGHT AS A
POTENTIAL MCS...OTHERWISE PREFER AN EVEN MIX OF THE GFS AND ECMWF
FOR WEATHER SPECIFICS THROUGH MIDWEEK...LEANING MORE TOWARD THE
LATTER BY THE END OF THE WEEK. ALSO INCLUDED A GENEROUS DIURNAL
CYCLE TO THE POP PATTERN AND MAGNITUDE...THOUGH...AS THE PAST SEVERAL
NIGHTS HAVE SHOWN...THE CONVECTION HAS BEEN ABLE TO THRIVE WELL PAST
PEAK HEATING...IN OUR AREA.
SENSIBLE WEATHER WILL FEATURE HIGH PRESSURE HOLDING ON FOR A MOSTLY
DRY DAY ON MONDAY BEFORE A WARM FRONT APPROACHES FROM THE WEST
POSSIBLY YIELDING SOME LATE DAY STORMS. THESE STORM CHANCES WILL
CONTINUE THROUGH THE NIGHT AS A SHOT OF MID LEVEL ENERGY LOOKS TO
DIVE THROUGH THE STATE AFTER DARK IN THE NAM12...WITH CONSIDERABLE
SUPPORT FROM THE LATEST ECMWF. OTHERWISE...WITH A WEAK PRESSURE
FIELD THROUGHOUT THE REGION...NORTHWEST FLOW ALOFT...AND A HUMID
ENVIRONMENT...EXPECT THE DIURNAL INSTABILITY CYCLE TO DRIVE THE
CONVECTIVE CHANCES INTO THE END OF THE WEEK WITH PERHAPS ANOTHER
BOUNDARY MOVING INTO THE CWA LATE IN THE PERIOD IN RESPONSE TO
CHANGES ALOFT. TEMPERATURES WILL BE SEASONABLY WARM THROUGH THE
EXTENDED WITH PLENTY OF HUMIDITY KEEPING THE LOWS FAIRLY HIGH AND
CONDITIONS MUGGY EACH NIGHT.
THE CR EXTENDED GRID PACKAGE CAME IN REASONABLE FOR THE PATTERN...
THOUGH DID MAKE ADJUSTMENTS TO THE DIURNAL/TEMPORAL PATTERN OF
MAXIMUM AND MINIMUM POPS THROUGH THE PERIOD. MADE ONLY MINOR TWEAKS
TO LOW TEMPERATURES EACH NIGHT AS THE TERRAIN EFFECTS WILL BE RATHER
LIMITED GIVEN THE STILL MOIST ENVIRONMENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 623 AM EDT SAT JUL 28 2012
AFTER SOME PATCHY MORNING VALLEY FOG...VFR CONDITIONS WILL TAKE HOLD
ACROSS THE AREA BY MID MORNING AND CONTINUING THROUGH THIS EVENING.
WE WILL LIKELY SEE MORE PATCHY VALLEY FOG TONIGHT AS CLEAR SKIES
DOMINATE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
623 AM EDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 623 AM EDT SAT JUL 28 2012
FORECAST IS IN PRETTY GOOD SHAPE THIS MORNING WITH SKIES CONTINUING
TO CLEAR OFF. THERE IS SOME PATCHY MORNING FOG IN THE VALLEYS WHICH
WILL BE BURNING OFF SHORTLY AFTER SUNRISE. COLD FRONT IS CONTINUING
TO MAKE STEADY PROGRESS TO THE SOUTH AND EAST. LATEST 06Z NAM KEEPS
ALL THE CONVECTION SOUTHEAST OF THE AREA TODAY...BUT THE HRRR SHOWS
SOME HINTS AT SOME DEVELOPMENT IN THE SOUTHEAST AROUND MIDDAY.
THUS...GOING TO HANG ONTO THE SMALL CHANCE FOR SHOWERS AND
THUNDERSTORMS FOR THE TIME BEING. IT IS POSSIBLE EVERYTHING ENDS UP
FURTHER SOUTHEAST AND THE AREA STAYS COMPLETELY DRY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 308 AM EDT SAT JUL 28 2012
COLD FRONT IS QUICKLY DROPPING SOUTHEAST...VIRTUALLY ALIGNED WITH THE
OHIO RIVER PRESENTLY. COMPLEX OF SHOWERS AND STORMS CONTINUES TO ROLL
ACROSS AREAS NEAR THE TENNESSEE BORDER. BASED ON RADAR TRENDS...THIS
ACTIVITY SHOULD CONTINUE TO DIMINISH AND EXIT OVER THE NEXT
HOUR...LEAVING BEHIND DRY CONDITIONS FOR THE REMAINDER OF THE
MORNING. COLD FRONT WILL ROCKET SOUTHEAST THIS MORNING...REACHING THE
VIRGINIA/KENTUCKY BORDER BY MID MORNING. WITH MOISTURE POOLING AHEAD
OF THE FRONT...A FEW SHOWERS OR STORMS COULD DEVELOP IN THE VICINITY
OF THE VIRGINIA BORDER BY MIDDAY INTO THE EARLY AFTERNOON. THIS
SHOULD ONLY IMPACT A SLIVER OF EASTERN KENTUCKY. THE REST OF THE AREA
WILL REMAIN DRY TODAY. THERE IS MARGINAL WIND SHEAR PRESENT...BUT
SEVERE THREAT WILL LIKELY BE CONFINED TO AREAS FURTHER SOUTHEAST OF
KENTUCKY.
HIGH PRESSURE WILL CONTINUE TO DEVELOP OVER THE REGION TODAY THROUGH
TONIGHT...KEEPING QUIET WEATHER AROUND THROUGH THE REMAINDER OF THE
WEEKEND.
A VERY PLEASANT WEEKEND IS ON TAP AS SLIGHTLY COOLER AND A LESS HUMID
AIRMASS SPREAD INTO EASTERN KENTUCKY HIGHS TODAY AND SUNDAY WILL TOP
OUT IN THE MID 80S WITH LOWS IN THE MID 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 445 AM EDT SAT JUL 28 2012
THE MODELS ARE IN DECENT AGREEMENT WITH THE GENERAL PATTERN ALOFT
THROUGH THE EXTENDED PORTION OF THE FORECAST. A SEMI-PERSISTENT TROUGH
WILL HOLD IN PLACE JUST TO THE NORTHEAST OF THE REGION THROUGH THE
MIDDLE OF NEXT WEEK. THIS WILL PROMOTE OCCASIONAL SHORTWAVES TO DROP
INTO THE OHIO VALLY ON NORTHWEST FLOW. A KEY ONE LOOKS TO MOVE
THROUGH LATE MONDAY. TOWARD THE END OF THE UPCOMING WORK WEEK THE
MODELS START TO DEVIATE FROM EACH OTHER WITH THE LATEST ECMWF PUSHING
THE WESTERN RIDGE FURTHER EAST AND FLATTENING OUT THE PATTERN
LOCALLY WHEN COMPARED TO THE GFS. ACCORDINGLY...PREFER A BLENDED
SOLUTION WHEN THE MODELS ARE CLOSE...BUT LEAN MORE TOWARD THE ECMWF
WHEN THEY START TO DEVIATE. DID HONOR THE SHORTWAVE THAT THE NAM12
AND THE 00Z ECMWF BRING DOWN INTO THE AREA MONDAY NIGHT AS A
POTENTIAL MCS...OTHERWISE PREFER AN EVEN MIX OF THE GFS AND ECMWF
FOR WEATHER SPECIFICS THROUGH MIDWEEK...LEANING MORE TOWARD THE
LATTER BY THE END OF THE WEEK. ALSO INCLUDED A GENEROUS DIURNAL
CYCLE TO THE POP PATTERN AND MAGNITUDE...THOUGH...AS THE PAST SEVERAL
NIGHTS HAVE SHOWN...THE CONVECTION HAS BEEN ABLE TO THRIVE WELL PAST
PEAK HEATING...IN OUR AREA.
SENSIBLE WEATHER WILL FEATURE HIGH PRESSURE HOLDING ON FOR A MOSTLY
DRY DAY ON MONDAY BEFORE A WARM FRONT APPROACHES FROM THE WEST
POSSIBLY YIELDING SOME LATE DAY STORMS. THESE STORM CHANCES WILL
CONTINUE THROUGH THE NIGHT AS A SHOT OF MID LEVEL ENERGY LOOKS TO
DIVE THROUGH THE STATE AFTER DARK IN THE NAM12...WITH CONSIDERABLE
SUPPORT FROM THE LATEST ECMWF. OTHERWISE...WITH A WEAK PRESSURE
FIELD THROUGHOUT THE REGION...NORTHWEST FLOW ALOFT...AND A HUMID
ENVIRONMENT...EXPECT THE DIURNAL INSTABILITY CYCLE TO DRIVE THE
CONVECTIVE CHANCES INTO THE END OF THE WEEK WITH PERHAPS ANOTHER
BOUNDARY MOVING INTO THE CWA LATE IN THE PERIOD IN RESPONSE TO
CHANGES ALOFT. TEMPERATURES WILL BE SEASONABLY WARM THROUGH THE
EXTENDED WITH PLENTY OF HUMIDITY KEEPING THE LOWS FAIRLY HIGH AND
CONDITIONS MUGGY EACH NIGHT.
THE CR EXTENDED GRID PACKAGE CAME IN REASONABLE FOR THE PATTERN...
THOUGH DID MAKE ADJUSTMENTS TO THE DIURNAL/TEMPORAL PATTERN OF
MAXIMUM AND MINIMUM POPS THROUGH THE PERIOD. MADE ONLY MINOR TWEAKS
TO LOW TEMPERATURES EACH NIGHT AS THE TERRAIN EFFECTS WILL BE RATHER
LIMITED GIVEN THE STILL MOIST ENVIRONMENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 623 AM EDT SAT JUL 28 2012
AFTER SOME PATCHY MORNING VALLEY FOG...VFR CONDITIONS WILL TAKE HOLD
ACROSS THE AREA BY MID MORNING AND CONTINUING THROUGH THIS EVENING.
WE WILL LIKELY SEE MORE PATCHY VALLEY FOG TONIGHT AS CLEAR SKIES
DOMINATE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
540 AM CDT SAT JUL 28 2012
.AVIATION...12Z KGRI TAF. A SURFACE TROUGH AXIS WILL BEGIN TO
SHIFT SOUTHEAST ACROSS THE REGION TODAY. AS A RESULT...WINDS WILL
GRADUALLY SHIFT TO BECOME MORE SOUTHERLY THIS MORNING...BEFORE
SWITCHING TO THE SOUTHWEST. BOUNDARY LAYER MIXING THIS AFTERNOON
WILL ALLOW INCREASED WINDS NEAR 15 KTS SUSTAINED AND WIND GUSTS
UP TO 20 KTS. THERE REMAINS CHANCE FOR SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS CENTRAL NEBRASKA. AT THIS TIME...LEFT MENTION
OUT OF TAF DUE TO SCATTERED NATURE OF ANY STORMS THAT SHOULD
DEVELOP...BUT WILL NEED TO BE MONITORED. INCREASED CLOUDS CAN BE
EXPECTED THIS AFTERNOON AND EVENING WITH THUNDERSTORM
DEVELOPMENT...BUT EXPECTING VFR CONDITIONS THROUGHOUT THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 440 AM CDT SAT JUL 28 2012/
SHORT TERM...TODAY THROUGH MONDAY NIGHT. MULTIPLE FORECAST
CONCERNS...ESP TODAY AND SUNDAY...INCLUDING
TEMPERATURES...PRECIP CHANCES...AND FIRE WEATHER ISSUES.
SATELLITE AND UPPER LEVEL PROFILER DATA CONTINUE TO SHOW THE
REGION UNDER THE INFLUENCE OF HIGH PRESSURE/RIDGING CENTERED
OVER THE SRN PLAINS...WHILE A WEAK DISTURBANCE CONTINUES TO RIDE
AROUND THE EDGE OF THE RIDGE...CURRENTLY OVER NERN NEB/SERN SD.
ANOTHER DISTURBANCE IS CURRENTLY MAKING ITS WAY THROUGH WY...WHICH
CAN ALSO BE PICKED OUT VIA LIGHTNING DATA. WAS CONCERNED LAST
NIGHT THAT THE ACTIVITY MAY STAY JUST NORTH OF THE CWA...AND AT
THIS POINT...LOOKS LIKE HOW IT IS GOING TO TURN OUT. AT THE
SURFACE...THE CWA SITS BETWEEN HIGH PRESSURE EXTENDING FROM NRN IA
INTO ERN CANADA...AND LOW PRESSURE DRAPED ALONG THE HIGH/SRN
PLAINS...BRINGING SOUTHEASTERLY FLOW...WITH SPEEDS GENERALLY
NEAR/LESS THAN 10 MPH.
LOOKING TO THE REST OF TODAY AND INTO TONIGHT...CONTINUE TO SEE
THE POTENTIAL FOR THUNDERSTORM ACTIVITY ACROSS THE
CWA...PRIMARILY THIS AFTERNOON/EVENING. EVEN THIS CLOSE IN
TIME...PLENTY OF MODEL DIFFERENCES REMAIN. THE GENERAL STORY LIES
WITH THAT NEXT DISTURBANCE MOVING ONTO THE PLAINS...WHICH LOOKS TO
SPARK OFF THUNDERSTORMS ACROSS THE REGION. A SURFACE TROUGH AXIS
IS EXPECTED TO PUSH SOUTH THROUGH THE DAY...BUT WHERE IT EXACTLY
ENDS UP CONTINUES TO BE DEBATED BETWEEN MODELS. THE NAM REMAINS ON
THE MORE AGGRESSIVE SIDE OF THINGS WITH THE THUNDERSTORM
DEVELOPMENT...WITH THE GFS/EC SHOWING VERY LITTLE. WITH SUPPORT
FROM THE 00Z 4KM WRF AND HRRR ALSO TRENDED MORE TOWARD THE NAM
/BUT NOT NEARLY AS WIDESPREAD/...DECIDED TO UP POPS INTO THE 30
PERCENT RANGE...MAINLY ACROSS SC NEB. DIDNT RAISE ANY HIGHER DUE
TO THOUGHT THAT THE NAMS COVERAGE COULD BE OVERDONE. DID KEEP
LINGERING POPS INTO THIS EVENING...BUT EXPECT THINGS TO BE WINDING
DOWN PRIOR TO MIDNIGHT. AS FAR AS SEVERE WEATHER GOES...FEEL THAT
WHAT THUNDERSTORMS DO DEVELOP LATER TODAY COULD BE CAPABLE OF
DAMAGING WINDS...WITH FORECAST SOUNDINGS SHOWING GOOD MIXING
POTENTIAL AND PLENTY OF DRIER AIR IN THE LOWER LEVELS. WILL GO
AHEAD AND INSERT THAT POSSIBILITY IN THE HWO. COULDNT RULE OUT
SOME QUARTER SIZE HAIL...BUT WINDS LOOK TO BE MORE A THREAT.
AS FAR AS TEMPERATURES GO...ONLY MINOR ADJUSTMENTS WERE MADE...AND
STILL EXPECTED TO BE WARMER THAN FRIDAY...AS WARMER AIR ALOFT
CONTINUES TO BUILD IN FROM THE WEST. FORECAST CURRENTLY CALLING
FOR MID 90S IN THE NORTHEAST TO 100-105 ACROSS THE SW CORNER OF
THE CWA. AS MENTIONED ABOVE...FORECAST SOUNDINGS /ESP IN THE SW/
SHOW GOOD MIXING POTENTIAL...AND AFTERNOON DEWPOINTS REFLECT THAT
POSSIBILITY. COMBINED WITH THE EXPECTED INCREASINGLY MORE
SOUTHWESTERLY COMPONENT TO THE WINDS...BY MID
AFTERNOON...EXPECTING TO SEE DEWPOINTS IN THOSE SOUTHWESTERN
LOCATIONS FALL INTO THE LOWER 50S...WHILE LOCATIONS GENERALLY
ALONG/NORTH OF I80 LOOK TO REMAIN CLOSER TO THE LOWER 60 PERCENT
RANGE. DID NOT GO WITH ANY HEAT ADV HEADLINE FOR TODAY ACROSS NC
KS /WHERE HIGHS ARE HOTTEST/...AS THE LOWER DEWPOINTS EXPECTED TO
ACCOMPANY THOSE TEMPERATURES SHOULD KEEP HEAT INDEX VALUES FROM
EXCEEDING 105 DEGREES ON A WIDESPREAD BASIS.
FORECAST FOR TODAY DID RAISE SOME CONCERNS ABOUT FIRE
WEATHER...SEE FIRE SECTION BELOW FOR MORE INFORMATION.
AS WE GET INTO SUNDAY/SUNDAY NIGHT...THUNDERSTORM CHANCES REMAIN
IN THE FORECAST. KEPT THE MORNING HOURS DRY...BUT AS THIS LATEST
DISTURBANCE MOVES THROUGH AND EVENTUALLY EAST OF THE CWA...MODELS
HAVE COME INTO BETTER AGREEMENT SHOWING THE SURFACE BOUNDARY
PUSHING FURTHER SOUTH THROUGH THE CWA...EVENTUALLY SETTLING AT
LEAST NEAR THE NEB/KS STATE LINE...IF NOT FURTHER SOUTH. DEPENDS
ON THE MODEL. HAVE SOME LOW POPS IN DURING THE AFTERNOON ACROSS
SOUTHERN PORTIONS OF THE CWA...CLOSE TO WEAR THE BOUNDARY COULD
BE. MADE LITTLE CHANGE TO THE EVENING/OVERNIGHT POPS...THE GFS
CONTINUES TO CERTAINLY BE ON THE MORE WIDESPREAD SIDE OF
THINGS...BUT FORECAST REMAINS TRENDED TOWARDS BETTER SUPPORT
JUSTIFYING LOWER POPS. MODELS SHOW AN INCREASE IN TEMPERATURES
ALOFT ACROSS THE REGION ON SUNDAY...BUT WITH THE MORE EASTERLY
COMPONENT TO THE WINDS...HARD TO GO MORE THAN A COUPLE OF DEGREES
WARMER THAN TODAY /DIDNT MAKE NOTABLE CHANGES TO THE INHERITED
TEMPERATURES/. AM CONCERNED THAT THOSE EASTERLY WINDS ARE GOING
HAVE A GREATER IMPACT ON THE TEMPERATURES /PRIMARILY ACROSS SC
NEB/...AND UPCOMING SHIFTS WILL HAVE TO TAKE A LOOK AT THAT. IF
THE BOUNDARY DOESNT GET AS FAR SOUTH AS SAY THE 06Z NAM
SUGGESTS...WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR HEAT ADV
CRITERIA ACROSS NC KS. AT THIS TIME...WITH PLENTY OF UNCERTAINTY
WASNT GOING TO GO DOWN THAT ROAD.
UNCERTAINTY WITH THE PRECIPITATION CHANCES CONTINUES INTO
MONDAY...AND KEPT LOW POPS IN PLACE ACROSS THE CWA. MODELS RANGE
FROM VERY LITTLE GOING ON ANYWHERE...TO WIDESPREAD ACTIVITY ACROSS
PORTIONS OF SC NEB...TO ACTIVITY DRIFTING INTO THE WEST FROM
EARLIER DEVELOPMENT ACROSS THE HIGH PLAINS. CANT REALLY NAIL
DOWN BETTER SPECIFICS WITH THE POPS UNTIL THERE IS BETTER
AGREEMENT WITH ANY SOLUTION BETWEEN THE MODELS. THERE IS BETTER
AGREEMENT IN REGARD TO TEMPERATURES...WHICH SHOW HIGHS BEING
COOLER THAN ON SUNDAY...WITH LOWER/MID 90S IN NEB...MID/UPPER 90S
IN KS. KEPT THE INHERITED DRY FORECAST FOR MONDAY NIGHT IN PLACE.
LONG TERM...TUESDAY THROUGH FRIDAY.
THE MAIN CONCERN FOR THE LONG TERM PERIOD WILL AGAIN FOCUS ON
CHANCES FOR SHOWERS AND THUNDERSTORMS. OTHERWISE...MADE VERY FEW
CHANGES TO THE EXTENDED.
WHILE AN UPPER LEVEL RIDGE REMAINS STEADFAST ACROSS THE WESTERN
TWO THIRDS OF THE CONUS TOWARDS THE BEGINNING OF THE LONG
TERM...AN UPPER LEVEL TROUGH OFF THE WESTERN COAST SLOWLY BEGINS
TO PUSH EASTWARD ACROSS CANADA...THUS HELPING BREAK DOWN THE UPPER
LEVEL RIDGE. IN ADDITION...NUMEROUS SHORT WAVES CONTINUE TO ROUND
THE TOP OF THE UPPER LEVEL RIDGE AND SKIRT ACROSS THE PLAINS.
ALTHOUGH TIMING AND PLACEMENT AS WELL AS RESOLUTION REMAIN
INCONSISTENT AMONG THE LONG TERM MODELS...THERE APPEARS TO BE SOME
CHANCE AT AN UPPER LEVEL DISTURBANCE PASSING THROUGH THE REGION
SOMETIME DURING THE LONG TERM PERIOD. AT THE SURFACE...LOW
PRESSURE ALONG THE NORTHERN ROCKIES IS EXPECTED TO SHIFT EASTWARD
ACROSS THE DAKOTAS...WHILE HIGH PRESSURE REMAINS SITUATED ACROSS
THE CENTRAL PLAINS...THROUGH AT LEAST THURSDAY MORNING. DEVELOPING
LOW PRESSURE ACROSS THE REGION ON THURSDAY...COMBINED WITH THE
POSSIBILITY OF AN UPPER LEVEL SHORT WAVE AND UPPER LEVEL JET
STREAK COULD CERTAINLY GENERATE SOME POPS ACROSS THE AREA. AT THIS
POINT...MODELS REMAIN TOO INCONSISTENT TO CONTINUE WITH SEVERAL
PERIODS OF SLIGHT CHANCE POPS. PER NEIGHBOR
COLLABORATION...CONTINUED A DRY FORECAST THROUGH MUCH OF THE
EXTENDED WITH THE EXCEPTION OF FRIDAY. FOR FRIDAY...MODELS ARE AT
LEAST IN AGREEMENT ON PLACEMENT OF A SURFACE LOW/TROUGH ALONG THE
HIGH PLAINS SHIFTING EASTWARD...AN UPPER LEVEL JET ACROSS PORTIONS
OF NEBRASKA...AND A WEAK UPPER LEVEL WAVE TRAVERSING THE REGION.
THUS ADDED SLIGHT CHANCES FOR POPS TO MOST OF THE OUTLOOK AREA ON
FRIDAY.
FIRE WEATHER...MAIN CONCERN IS GOING TO LIE ACROSS THE
SOUTHWESTERN THIRD OF THE CWA...WHERE THE BETTER MIXING
POTENTIAL...AND THUS LOWER DEWPOINTS AND HIGHER TEMPERATURES WILL
EXIST. DEBATED ISSUING A HEADLINE FOR PORTIONS OF NC KS THIS
AFTERNOON...AS FORECAST RELATIVE HUMIDITY VALUES ARE EXPECTED TO
FALL TO NEAR/JUST BELOW 20 PERCENT. THE LIMITING FACTOR LIES WITH
THE WINDS. THE MAJORITY OF MODEL DATA AND GUIDANCE KEEPS SUSTAINED
WIND SPEEDS BELOW CRITICAL LEVELS...AND FORECAST SOUNDINGS SHOW
THE HIGHER WINDS ALOFT/GUST POTENTIAL HAPPENING EARLIER IN THE
AFTERNOON...BEFORE THE RH VALUES DROP. CONFIDENCE IN THE WIND/WIND
GUST AND RH CRITERIA BOTH BEING MET FOR 3 HOURS WAS LOW ENOUGH TO
NOT ISSUE A HEADLINE. HOWEVER...IT WILL BE SOMETHING FOR THE DAY
SHIFT CREW TO KEEP A CLOSE EYE ON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT/FIRE WEATHER...ADO
LONG/AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1010 AM CDT SAT JUL 28 2012
.DISCUSSION...
THE SHORTWAVE IMPULSE NEAR KDIK PER 1445 UTC SATELLITE IMAGERY
WILL SLIDE EASTWARD TODAY. THE 12 UTC HRRR SUGGESTS THAT THIS
FEATURE WILL PROVIDE AMPLE BROAD SCALE ASCENT TO BREAK THE WEAK
CAP CURRENTLY OVER THE AREA AROUND 18 OR 19 UTC. SKY AND
PRECIPITATION GRIDS HAVE BEEN ADJUSTED ACCORDINGLY...WITH SOME
RESPECT ALSO GIVEN TO THE 09 UTC SREF MEAN.
THE MAIN FORECAST PROBLEM TODAY WILL BE TIMING AND COVERAGE OF
THUNDERSTORMS AND THE THREAT OF SEVERE WEATHER.
&&
.AVIATION...
ADDED VCTS TO KDIK FOR A COUPLE OF HOURS AS CONVECTION DEVELOPED
WEST OF THE TAF SITE AND CONTINUED TO MOVE EASTWARD TOWARDS KDIK.
EXPECT AMENDMENTS TO TAFS THROUGH THE DAY AS MODELS ARE DEPICTING
SMALL UPPER LEVEL DISTURBANCES MOVING WEST TO EAST ACROSS THE STATE
TODAY...AND THINK CONVECTION MAY DEVELOP ON AND OFF DURING THE
AFTERNOON. OTHERWISE VFR CONDITIONS EXPECTED FOR ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...SCHECK
AVIATION...JV
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1117 AM MDT SAT JUL 28 2012
.UPDATE...
LATEST OBS/RADAR SHOWING BOUNDARY MAKING A STRONGER PUSH SOUTHWARD
THAN PREVIOUS MODELS HAD INDICATED. NORTH WINDS HAVE ALREADY
SPREAD INTO NRN PUEBLO COUNTY...AND LATEST HRRR PLACES THIS
BOUNDARY ALONG AN AXIS FROM WALSENBURG TO KLHX...TO ARLINGTON BY 20Z.
TO THE NORTH OF THIS BOUNDARY...DEW POINTS MIX OUT INTO THE LOWER
40S...POSSIBLY EVEN SOME UPPER 30S...WHILE 40S PERSIST TO THE
SOUTH AND EAST OF THIS BOUNDARY. HRRR BREAKS OUT SOME HIGH BASED
CONVECTION ALONG THIS AXIS IN THE AFTERNOON. WHILE COVERAGE LOOKS
A LITTLE OVERDONE...HAVE EXPANDED SOME 15-20 PERCENT POPS SOUTH
AND EASTWARD. LATEST HRRR AND RUC KEEP ANY PRECIPITATION OFF THE
WALDO CANYON BURN SCAR UNTIL AFTER 21Z...AND WITH BOUNDARY
POSITIONED FARTHER TO THE SOUTH...THIS LOOKS PLAUSIBLE. WE WILL
STILL BE UNDER THE MONSOON PLUME THOUGH...AND SUBJECT TO HIT OR
MISS STORMS FIRED OFF BY CONVECTIVE HEATING. WITH PRECIP WATERS IN
12Z SOUNDINGS RUNNING AROUND 115 PERCENT OF NORMAL ACROSS THE
EAST...AND 150 PERCENT OF NORMAL ACROSS WESTERN CO...LOCALLY HEAVY
RAINFALL WILL BE THE PRIMARY THREAT WITH ANY STORMS. WITH THE HIGH
LCLS...DON`T SEE ENOUGH OF A THREAT TO WARRANT A FLASH FLOOD WATCH
FOR THE WALDO BURN SCAR...BUT CLOSE MONITORING OF STORMS WILL BE
NEEDED THIS AFTERNOON...AS A DIRECT HIT FROM A STRONGER STORM
WOULD CERTAINLY BE SUFFICIENT TO CAUSE FLASH FLOODING. -KT
&&
.AVIATION...
VFR CONDITIONS EXPECTED AT TAF SITES WITH TSRA DEVELOPING ACROSS
THE MOUNTAINS AROUND 18Z. VCTS WILL BE POSSIBLE AT ALL THREE TAF
SITES AFTER BEGINNING AROUND 20-21Z...THOUGH KALS WILL HAVE THE
BEST CHANCE AND WILL INTRODUCE A TEMPO GROUP FROM 20Z-23Z. GUSTY
ERRATIC WINDS FROM THUNDERSTORM OUTFLOWS WILL BE POSSIBLE AT ALL 3
TAF SITES THIS AFTERNOON WITH GUSTS UP TO 35-40 KTS POSSIBLE.
MEANWHILE...MTN AREAS WILL SEE SCATTERED TO NUMEROUS THUNDERSTORMS
WITH MTN OBSCURATIONS AT TIMES DUE TO TSRA...ESPECIALLY ALONG THE
CONTINENTAL DIVIDE WHERE TSRA WILL BE MOST NUMEROUS. THUNDERSTORMS
WILL DIMINISH AFTER SUNSET WITH VFR CONVECTIVE DEBRIS CLOUDINESS
GRADUALLY DECREASING THROUGH THE NIGHT. -KT
&&
.PREV DISCUSSION... /ISSUED 415 AM MDT SAT JUL 28 2012/
SHORT TERM...
(TODAY AND TONIGHT)
CURRENTLY...THE UPPER RIDGE AXIS REMAINED OVER WESTERN KS EARLY THIS
MORNING WITH THE VERY EVIDENT MONSOON PLUME BEING DRAWN UP ACROSS
THE 4 CORNERS AND INTO CO...AS PER RAP H5 ANALYSIS AND IR SATELLITE
IMAGERY. SFC OBS INDICATED THAT TEMPS HAD DROPPED INTO THE UPPER 50S
TO MID 60S FOR MOST PLAINS LOCATIONS AND DOWN TO AROUND 50F FOR THE
HIGH VALLEYS AS OF 330 AM. DEWPOINT TEMPS WERE FAIRLY UNIFORM FOR
THE CWA...IN THE MID 40S TO LOWER 50S.
TODAY AND TONIGHT...THE WEATHER TREND FOR TODAY LOOKS LIKE IT WILL
BE VERY SIMILAR TO FRIDAY...MINUS THE SPARK PROVIDED BY THE UPPER
DISTURBANCE THAT ROLLED ACROSS THE ROCKIES. PRECIPITABLE WATER
REMAINS AT OR SLIGHTLY ABOVE NORM...BUT UPPER AIR SOUNDINGS POINT
TO SOMEWHAT DRY LOW LEVELS. THE RIDGE AXIS REMAINING NEAR THE
CO/KS BORDER WILL IMPART A GRADUAL N-NE MOVEMENT FOR ANY STORMS
THAT DO DEVELOP OVER THE HIGHER TERRAIN THIS AFTN. MODELS ARE
HINTING AT A SFC BOUNDARY LURKING ALONG THE PALMER DVD THIS
AFTN...AND WHERE THIS BOUNDARY STALLS WILL BE A FOCUS AREA FOR
CONVECTION. DECIDED TO HOLD ONTO THE ONGOING FORECAST THAT KEEPS
THIS BOUNDARY PRIMARILY NORTH OF THE PALMER DVD...WITH CONVECTION
FIRING OVER MONUMENT HILL THIS AFTN BUT NOT ALONG KIOWA COUNTY.
EXPECT ANOTHER HOT DAY TODAY WITH MAX TEMPS RIGHT AROUND 100 F FOR
THE PLAINS...AND IN THE 80S FOR THE HIGH VALLEYS.
THE MAIN FORECAST CONCERN CONTINUES TO BE THE FLASH FLOOD POTENTIAL
FOR THE WALDO CANYON BURN SCAR THIS AFTN AND EVE. INDIVIDUAL STORMS
HAVE SHOWN SOME SPOTTY HIGHER RAINFALL RATES OVER THE PAST WEEK AND
LUCKILY HAVE SIDE-STEPPED THE BURN SCAR FOR THE MOST PART...BUT WITH
LITTLE CHANGE IN THE OVERALL PATTERN LOCALLY HEAVY RAINFALL REMAINS
A THREAT. 27
LONG TERM...
(SUNDAY THROUGH SATURDAY)
CONCERNS ARE COVERAGE OF SLOW MOVING THUNDERSTORMS THROUGH THE
WEEK...ESPECIALLY MONDAY.
SUNDAY THROUGH MONDAY...UPPER RIDGE CENTERED OVER WESTERN US WILL
PROVIDE WEAK WEST TO SOUTHWEST FLOW ALOFT. A SHORTWAVE MOVING
SOUTHEAST THROUGH THE GREAT PLAINS WILL BRING A COUPLE OF
BOUNDARIES INTO EASTERN COLORADO. THE STRONGER PUSH OF
COOLER...AND SLIGHTLY MOISTER LOW LEVEL AIR WILL LIKELY OCCUR
SUNDAY NIGHT WITH EASTERLY UPSLOPE FLOW DEVELOPING ACROSS THE
PLAINS THROUGH THE DAY ON MONDAY. BUT...MONSOONAL MOISTURE
FORECAST TO MOVE MAINLY WEST AND NORTH OF THE CWA. ISOLATED TO
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL
OCCUR...WITH BEST COVERAGE REMAINING OVER AND ADJACENT TO THE
MOUNTAINS. WEAK FLOW ALOFT WILL BRING THE THREAT FOR LOCALLY HEAVY
RAINFALL AND THE POSSIBILITY OF FLASH FLOODING...ESPECIALLY IF
CELLS DEVELOP OVER THE BURN SCARS...INCLUDING THE WALDO CANYON
BURN SCAR. MID LEVEL TEMPERATURES WILL BE A BIT LOWER ON MONDAY
ACROSS THE PLAINS...BUT STILL...TEMPERATURES WILL BE ABOVE
SEASONAL AVERAGES BOTH DAYS.
TUESDAY-FRIDAY...UPPER LEVEL RIDGE FORECAST TO PERSIST JUST SOUTH
OF THE AREA...WITH RESULTANT WEAK WESTERLY FLOW ALOFT. MODELS
ALSO NOT TOO HEAVY HANDED WITH THE MONSOON MOISTURE. THERE WILL BE
ENOUGH MOISTURE FOR DAILY ISOLATED TO SCATTERED COVERAGE OF
PRECIPITATION WITH TEMPERATURES RISING A BIT FROM EARLY WEEKS
LEVELS. -TLM-
AVIATION...
VFR CONDITIONS ARE EXPECTED FOR THE THREE MAIN TAF SITES OF
KCOS...KPUB AND KALS FOR THE NEXT 24 HRS. HOWEVER...ISOLATED
CONVECTION WILL AFFECT KCOS AND KALS AFTER 18Z AND LASTING THROUGH
03Z...WITH THE MAIN THREAT BEING GUSTY WINDS OF 35-40 KTS. STORMS
WILL BE MORE SCATTERED OVER THE HIGHER TERRAIN...LINGERING THE
LONGEST OVER THE CONTDVD. THE STEERING FLOW IS FORECAST TO REMAIN
GENERALLY LIGHT AND FROM THE S-SW...SO ANY STORMS THAT FORM OVER THE
MTS WILL SLOWLY MOVE TO THE N-NE. 27
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31/77
AREA FORECAST DISCUSSION
NWS DENVER CO
1029 AM MDT SAT JUL 28 2012
.UPDATE...WEAK NORTHERLY PUSH MOVED ACROSS THE PLAINS THIS
MORNING. THIS SLIGHTLY COOLER BOUNDARY LAYER...COMBINED WITH SOME
MID LEVEL CLOUDINESS...HAS DELAYED THE PLAINS HEATING A BIT AND
WILL LIKELY ALLOW THE CAP TO HOLD IN PLACE TIL LATE AFTERNOON. AS
A RESULT...HAVE DELAYED THE POPS A BIT ON THE PLAINS WHILE
LOWERING THEM SLIGHTLY OVER THE NORTHEASTERN PORTIONS OF THE
PLAINS WHERE CAP IS NORMALLY STRONGEST IN THESE SITUATIONS. LATEST
HRRR AND RAP ALSO SUGGEST A LATER ARRIVAL OF CONVECTION ON THE
PLAINS...AND EVEN HINT AT THE CAP REMAINING STRONG ENOUGH TO
PREVENT CONVECTION THIS AFTERNOON. WILL CONTINUE TO MONITOR
PROGRESSION.
MEANWHILE...THE MOUNTAINS AND FOOTHILLS SHOULD SEE ANOTHER ACTIVE
DAY WITH PLENTY OF PW AND VALUES ABOUT 0.10 TO 0.20 INCH HIGHER
THAN YESTERDAY. LOOKS LIKE THE BEST MOISTURE PLUME IS AIMING
TOWARD SUMMIT/PARK COUNTIES AND THE SOUTHERN FOOTHILLS. THE WEAK
Q-G SUBSIDENCE SHOULD ALSO ABATE LATER THIS AFTERNOON PER THE
LATEST Q-G ANALYSIS/TRENDS ALLOWING FOR RATHER HIGH CONVECTIVE
COVERAGE.
&&
.AVIATION...PER DISCUSSION ABOVE...CAP WILL LIKELY TAKE LONGER TO
ERODE ACROSS THE PLAINS THIS AFTERNOON/EVENING WITH WEAK BOUNDARY
LAYER COOLING AND SOME MID LEVEL CLOUDINESS. WILL PUSH BACK
THUNDER CHANCES A COUPLE HOURS AND CENTER IT CLOSER TO 00Z. SOME
CHANCE THAT CONVECTION MAY NOT AFFECT FRONT RANGE AIRPORTS IF CAP
IS A LITTLE STRONGER. WILL MONITOR LATEST ACARS SOUNDINGS FOR
THUNDER UPDATES THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 345 AM MDT SAT JUL 28 2012/
SHORT TERM...BROAD HIGH PRESSURE ALOFT CENTERED OVER THE
PANHANDLES OF TEXAS AND OKLAHOMA WITH A HEALTHY WESTERLY FLOW
ALOFT OVER NORTHERN COLORADO. WATER VAPOR IMAGERY CONTINUES TO SHOW THE
MOISTURE PLUME OVER MUCH OF COLORADO STREAMING IN FROM ARIZONA AND
WESTERN NEW MEXICO. GIVEN SATELLITE TRENDS DON`T REALLY SEE MUCH
CHANGE IN THE OVERALL MOISTURE LEVELS THROUGH TONIGHT. CURRENT IPW
VALUES FROM GPS ARE JUST UNDER AN INCH OVER THE PLAINS. BOTH
NAM/GFS BUMP UP PW VALUES TO JUST OVER AN INCH BY AFTERNOON.
HOWEVER BOTH GFS/NAM SEEM TO KEEP MOST OF THE PRECIP OVER THE
MOUNTAINS...FOOTHILLS AND PALMER DIVIDE WITH VERY LITTLE PRECIP
OVER THE PLAINS. GIVEN THE WESTERLY FLOW DON`T SEE WHY THE STORMS
WON`T BE ABLE TO MAKE IT OVER ONTO THE PLAINS. MODEL DEWPOINTS SEE
A BIT LOW AS WE SHOULD BE ABLE TO HOLD DEWPOINTS IN THE MID 40S TO
AROUND 50. THIS WILL RESULT IN SFC BASED CAPES FROM 500-1000J/KG.
HAVE BUMPED UP POPS 10 PERCENT ACROSS THE BOARD OVER THE PLAINS
FOR THIS AFTERNOON AND EVENING.
LONG TERM...THE STRONG UPPER LEVEL SUBTROPICAL HIGH PRESSURE
RIDGE CENTERED OVER OKLAHOMA SUNDAY MORNING IS FORECAST TO SHIFT
SOUTHWARD OVER NORTHERN TEXAS DURING THE DAY. THIS ALLOWS THE
PLUME OF MOIST SUBTROPICAL AIR HOVERING OVER THE DESERT SOUTHWEST
TO STREAM NORTHEASTWARD OVER COLORADO THROUGH SUNDAY NIGHT.
MODELS SHOW 850-500MB PRECIPITABLE WATER AND MEAN LAYER SPECIFIC
HUMIDITY VALUES CLIMBING DURING THE DAY SUNDAY AS THE MAIN PUSH OF
MOISTURE PASSES OVER THE FORECAST AREA LATE IN THE DAY. NAM DOES
NOT INDICATE ALL THAT MUCH QUASI-GEOSTROPHIC ASCENT OR SFC-500MB
INSTABILITY AROUND ON SUNDAY. WHEREAS THE GFS SHOWS ABOUT THE SAME
AMOUNT OF Q-G LIFT BUT QUITE A BIT MORE LOW-LEVEL CAPE/INSTABILITY
DUE LARGELY TO MORE PRECIPITABLE WATER AROUND. ECMWF CAPE AND Q-G
ASCENT ABOUT THE SAME AS THAT ON THE GFS. MEANWHILE SOUTHWEST
FLOW ALOFT IS RELATIVELY WEAK ON ALL THREE MODELS ON SUNDAY. LIGHT
EASTERLY/UPSLOPE FLOW ALSO ACCOUNTING FOR THE INCREASE IN LOW-
LEVEL MOISTURE EAST OF THE MTNS. PW VALUES SOMEWHERE BETWEEN 0.80
AND 1.10 INCH ON THE PLAINS BY LATE AFTERNOON AND ABOUT 0.70 INCH
IN THE HIGH COUNTRY. WITH THIS MUCH WATER VAPOR HANGING AROUND...
COULD SEE SKIES CLOUDING OVER BEFORE SOLAR HEATING HAS TIME TO
GENERATE STORMS. THAT MAY EXPLAIN THE LOW POPS OFFERED BY THE
MODEL GUIDANCE. STILL FEEL THERE/S SUFFICIENT CAUSE TO STICK WITH
THE 20-30 PCT POPS ON THE PLAINS AND 30-50 PCT POPS IN THE HIGH
COUNTRY SUNDAY AFTERNOON AND EVENING. HOWEVER IT MAY REQUIRE
BOUNDARIES MOVING DOWN FROM STORMS SCATTERED OVER THE FOOTHILLS TO
INITIATE STORM DEVELOPMENT OVER THE ADJACENT PLAINS. THIS MAY NOT
HAPPEN UNTIL LATE..SAY 5 OR 6 PM DEPENDING ON THE AMOUNT OF CLOUD
COVERAGE. SLOW STORM MOTIONS AND THE POSSIBILITY OF TRAINING
STORMS COULD RESULT IN LOCALLY HEAVY RAINFALL...UPWARDS OF AN INCH
IN UNDER 30 MINUTES...MAINLY OVER AND NEAR THE FRONT RANGE. AS HAS
BEEN THE CASE THIS SUMMER...BURN SCARS MOST SUSCEPTIBLE TO FLASH
FLOODING SHOULD THIS SCENARIO PAN OUT.
COULD SEE STORMS LINGERING ON THE PLAINS WELL INTO THE OVERNIGHT
HOURS...MAINLY OUT NEAR THE EASTERN BORDER. LACK OF SHEAR OR MUCH
INSTABILITY SHOULD LIMIT SEVERE WX BUT BRIEF HEAVY RAIN STILL
POSSIBLE.
FOR MONDAY AND TUESDAY...THE SUBTROPICAL HIGH OVER NORTHERN TEXAS
ON SUNDAY MIGRATES WESTWARD OVER THE TEXAS/OKLAHOMA PANHANDLE
ON MONDAY WHERE IT LINGERS THROUGH TUESDAY. AS A CONSEQUENCE
STEERING WINDS ALOFT OVER NORTHEAST COLORADO BECOME MORE WESTERLY
IN DIRECTION. PULSES OF MONSOONAL MOISTURE CARRIED ALONG BY THIS
FLOW SHOULD KEEP THE CHANCE OF THE T-STORMS GOING IN THE HIGH
COUNTRY THROUGH TUESDAY EVENING. WHEREAS THIS SAME WESTERLY FLOW
WILL LIKELY REDUCE THE CHANCE OF STORMS ON THE PLAINS EVEN WITH
ALL OF THE MOISTURE AT MID-LEVELS. CAN/T RULE OUT A FEW STORMS
DRIFTING OFF THE FOOTHILLS AND OVER THE NEARBY PLAINS CAPABLE OF
BRIEF HEAVY RAIN IN THE AFTERNOON AND EVENING BOTH DAYS. STORMS
ARE NOT EXPECTED TO MOVE TOO FAR OUT OVER THE PLAINS WHERE THE
ATMOSPHERE LOOKS STRONGLY CAPPED.
FOR WEDNESDAY AND THURSDAY...WESTERLY FLOW ALOFT REMAINS IN PLACE
WITH THE UPPER LEVEL HIGH CONTINUING ITS SLOW WESTWARD TRACK ACROSS
NORTHERN NEW MEXICO. WEDNESDAY LOOKS DRIER...EVEN IN THE HIGH
COUNTRY...WITH SUBSIDENCE/WARMING ALOFT. BY THURSDAY...MODELS
INDICATE A RESURGENCE IN SUBTROPICAL MOISTURE ASSOCIATED WITH THE
PASSAGE OF A WEAK UPPER AIR DISTURBANCE. MEDIUM RANGE MODELS SHOW
THIS WAVE PASSING OVER THE FORECAST AREA AROUND MAX HEATING. SO
THE CHANCE FOR T-STORMS SLIGHTLY BETTER ON THURSDAY...ESPLY IN
THE HIGH COUNTRY. COULD SEE A REPEAT ON FRIDAY IF THE GFS IS
CORRECT. WHEREAS THE ECMWF APPEARS DRIER AND LESS ACTIVE.
TEMPERATURES THROUGHOUT THE EXTENDED PERIOD ARE PROGGED TO REMAIN
ABOVE AVERAGE WITH THE WARMEST READINGS MID-WEEK.
AVIATION...WITH NEXT 12Z TAF ISSUANCE WILL LIKELY INCREASE
CHANCES OF TS THIS AFTERNOON WITH TEMPO FOR TS/GUSTY WINDS GIVEN
SIMILAR MOISTURE LEVELS COMPARED TO YESTERDAY. TIMING OF STORMS MAYBE
A BIT LATER TODAY WITH MORE CLOUD COVER EXPECTED DURING THE
MORNING HOURS.
HYDROLOGY...GIVEN PW VALUES AROUND AN INCH AGAIN TODAY...SOME OF
THE STRONGER STORMS CAPABLE OF PRODUCING UP TO 2 INCHES IN LESS
THAN ONE HOUR. THIS WOULD RESULT IN POSSIBLE FLASH FLOODING
ESPECIALLY IN BURN AREAS. HOWEVER STORM MOTIONS OF 10-15KT SHOULD
KEEP THINGS MOVING AND NOT RESULT IN ANY MAJOR FLASH FLOODING
TODAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1254 PM CDT SAT JUL 28 2012
.DISCUSSION...
ISSUED 1045 AM CDT SAT JUL 28 2012
WILL BE UPDATING THE FORECAST TODAY FOR MORE CLOUD COVER TODAY AND
MAY NEED TO ADD SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS LATE
THIS AFTERNOON NW OF THE IL RIVER. OTHERWISE REST OF FORECAST
LOOKS OK WITH HIGHS RANGING FROM THE MID 80S FROM LINCOLN NW TO
THE LOWER 90S IN SE IL. A WEAK/SMALL MCS OVER CENTRAL/NW IA INTO
SE SD AND SW MN IS SPREADING MID/HIGH CLOUDS QUICKLY SE INTO
CENTRAL IL THIS MORNING. ALSO HAVE SCATTERED CUMULUS CLOUDS
DEVELOPING BY LATE MORNING ACROSS AREAS EAST OF I-55 WITH BROKEN
CEILINGS OVER PARTS OF CENTRAL INDIANA. MODELS WEAKEN SHOWERS AND
THUNDERSTORMS OVER CENTRAL AND NW IA AS THEY TRACK SE INTO NW IL
THIS AFTERNOON. NAM KEEPS IT DRY OVER CWA THROUGH TONIGHT BUT HRRR
BRINGS PATCHES OF QPF INTO AREAS ALONG AND NORTH OF I-74 LATER
THIS AFTERNOON AND EVENING. WITH SEVERE TO EXTREME DROUGHT OVER
CENTRAL IL...THINK HRRR IS OVERDOING QPF BUT THINK NAM MAY BE TOO
DRY INTO TONIGHT SO WILL USE A BLEND THERE.
KH
&&
.AVIATION...
ISSUED 1250 PM CDT SAT JUL 28 2012
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS THE
CENTRAL IL TERMINAL AIRPORTS THROUGH 18Z/1 PM SUNDAY. VFR BROKEN
CEILINGS OF 3.5-5K FT POSSIBLE THIS AFTERNOON EAST OF I-55
ESPECIALLY AT BMI...DEC AND CMI AIRPORTS WHILE BROKEN MID/HIGH
CLOUDS 12-20K FT CONTINUE TO STREAM SE ACROSS CENTRAL IL FROM IA.
SHOWERS AND ISOLATED THUNDERSTORM COMPLEX OVER CENTRAL IA TO
WEAKEN AS IT MOVES SE INTO NW IL THIS AFTERNOON. MODELS DIFFER
WITH EVOLUTION OF CONVECTION DEVELOPMENT TONIGHT BUT CONSENSUS IS
KEEPING MOST OF CENTRAL IL DRY TONIGHT WITH VCSH AT PIA LATE
TONIGHT INTO SUNDAY MORNING AND POSSIBLY APPROACHING I-55 DURING
SUNDAY MORNING. WITH SEVERE TO EXTREME DROUGHT OVER CENTRAL IL
THINK ANY CONVECTION THAT TRIES TO MOVE INTO CENTRAL IL WILL WEAKEN
AND DISSIPATE THROUGH TONIGHT. A LITTLE BETTER CHANCES OF ISOLATED
CONVECTION SUNDAY AFTERNOON AND SUNDAY NIGHT BEYOND THE 24 HOUR
TAF PERIOD. NW WINDS 5-10 KTS THIS AFTERNOON TO VEER EAST TONIGHT
AND SSE SUNDAY MORNING AT 7-11 KTS.
KH
&&
.PREV DISCUSSION...
ISSUED 242 AM CDT SAT JUL 28 2012
LATEST SFC ANALYSIS INDICATED HIGH PRESSURE OVER THE UPPER
MIDWEST. THIS PROVIDED LIGHT NORTHERLY WINDS AND SLIGHTLY
COOLER/LESS HUMID AIR. ALOFT...NORTHWEST MID LEVEL FLOW PREVAILED
FOR MUCH OF THE MIDWEST...BETWEEN AN EASTERN GREAT LAKES TROUGH
AND STRONG CENTRAL PLAINS RIDGING. MAIN FORECAST ISSUE CONTINUES TO
BE TRYING TO PIN DOWN PRECIP CHANCES IN NORTHWEST FLOW...AS OUR
AREA LOOKS TO BE ON THE EDGE OF THE HEAT DOME FOR MUCH OF THE FORECAST.
SHORT TERM...TODAY THROUGH MONDAY
SURFACE HIGH DRIFTS SOUTHEAST THROUGH THE EASTERN GREAT LAKES THIS
WEEKEND. THIS WILL PROVIDE A NORTH/EAST WIND FLOW TODAY WHICH
KEEPS TEMPERATURES NEAR TO SLIGHTLY ABOVE NORMAL. SOUTHERLY WINDS
ON THE BACK SIDE OF THE HIGH WILL WARM TEMPS A FEW MORE DEGREES
SUNDAY. FOR RAIN CHANCES...TO OUR WEST...MID LEVEL THERMAL
GRADIENT...LOW-LEVEL JET...AND SHORTWAVES TOPPING THE UPPER LEVEL
RIDGE WILL PRODUCE NIGHTLY MCS ACTIVITY. THE FIRST OF THESE WAVES
CURRENTLY OVER THE SD/NEBRASKA BORDER IS FORECAST TO SPREAD
THUNDERSTORMS INTO IOWA TODAY BEFORE DISSIPATING. MAIN IMPACT
LOCALLY WOULD BE AN INCREASE MID/HIGH LEVEL CLOUDS. NEXT
DISTURBANCE IS PROGGED TO DEVELOP STORMS OVER CENTRAL IOWA AFTER
06Z TONIGHT AND DROP SOUTHEAST ALONG MID LEVEL THERMAL/MOISTURE
GRADIENT. CONDITIONS ARE LESS FAVORABLE FOR THIS ACTIVITY TO HOLD
TOGETHER AS IS SHIFTS EAST OF THE MISSISSIPPI RIVER SUNDAY
MORNING. HAVE LIMITED POPS TO LOW CHANCE IN THE WEST...WITH SLIGHT
CHANCES FARTHER EAST. A SOMEWHAT BETTER SETUP FOR THUNDERSTORMS
SETS UP OVER THE AREA SUNDAY NIGHT INTO MONDAY WITH A MORE
FAVORABLE LOW-LEVEL JET ORIENTATION AND THETA-E GRADIENT...HOWEVER
FORCING IS NOT THAT IMPRESSIVE AND AGAIN LIMITED POPS TO LOW
CHANCE.
LONG TERM...TUESDAY THROUGH FRIDAY
LITTLE CHANGE IN THE OVERALL SYNOPTIC PATTERN IS SHOWN BY
TONIGHTS 00Z MEDIUM RANGE MODELS. A GENERAL NORTHWEST MID-LEVEL
FLOW CONTINUES AS THE STRONG SOUTHERN PLAINS RIDGE PERSISTS.
ACCEPTED ECMWF 850 MB TEMPS WARM TO +20C OR GREATER WHICH WOULD
SUPPORT ANOTHER STRETCH OF WARM WEATHER WITH HIGHS IN THE 90S AND
LOWS IN THE 70S. HOWEVER...THIS PATTERN DOES NOT APPEAR NEARLY AS
HOT AS LAST WEEK. PRECIP CHANCES WILL BE HIGHLY DEPENDENT ON
SHORTWAVES MOVING THROUGH IN FASTER FLOW ON THE PERIPHERY OF THE
HOT/CAPPED AIRMASS CENTERED TO OUR WEST. THIS WILL BE REFINED IN
LATER FORECASTS BUT GIVEN EXTREME DROUGHT HAVE KEPT POPS TO SLIGHT
CHANCE OR LESS.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1251 PM EDT SAT JUL 28 2012
.AVIATION... / 18Z TAFS /
NORTHERLY WINDS NEAR 10 KNOTS WILL BECOME LIGHT/VARIABLE TONIGHT
INTO TOMORROW MORNING AS SFC HIGH PRESSUIRE BUILDS INTO THE
REGION. AS FOR CIGS...MAINLY SKC AT SBN WITH A GRADUAL INCREASE IN
HIGH CLOUDS POSSIBLE BY LATER TONIGHT. FWA IS ON THE EASTERN
FRINGE OF A STRATO CU DECK NEAR 3 KFT. CONTINUED MIXING/SUBSIDENCE
SHOULD ALLOWING CIGS TO CONTINUE TO SCATTER OUT THIS AFTERNOON AND
INCREASE TO 4-5 KFT. OTHERWISE...TEMPS TONIGHT MAY NEAR XOVER
VALUES AT FWA POSSIBLY SUPPORTING A BRIEF PERIOD OF BR AROUND
DAYBREAK. LEFT ANY BR MENTION OUT OF THE FCST FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 700 AM EDT SAT JUL 28 2012/
SHORT TERM...
TODAY THROUGH SUNDAY NIGHT. BENIGN PATTERN IN SHORT
TERM PD. 1021 MB SFC HIGH ACRS NRN WI TO DROP SLOWLY SEWD INTO LWR
GRTLKS BY MON AM. STATIC MIDLVL REGIME FEATURING STRONG OK/NRN TX
RIDGE CENTER WITH MULTIPLE SHORTWAVES RIDING BROAD WRLIES ACRS NRN
PLAINS/SRN CANADA...THEN TRACKING INTO MEAN ERN STATES TROF.
ANTICIPATE FURTHER EXPANSION WITHIN 925MB THERMAL TROF ACRS SRN
MI/NRN IN THIS AM AMID TURBULENT N-NERLY 10-15KT FLOW PER KDTX VWP
AND RAP POINT SNDGS. RAPID MIXOUT OF CLOUDS COINCIDENT WITH RAPID
EROSION OF LOW BASED SUBSIDENCE INVERSION/RAPID RISING
CCL/ENTRAINMENT OF SIG DRIER AIR ALOFT. SLIGHT DOWNWARD NUDGE IN
TEMPS TODAY PER AM CLOUD COVER/DEEP NRLY FLOW/GUID
CLUSTERING/SIMILAR THERMAL REGIME AS SEEN YDAY ACRS SRN WI. SLIGHT
NUDGE TOWARD NAM/ECMWF WRT NEXT MINIMAL TSRA CHCS ACRS SWRN CWA
LATE SUNDAY NIGHT/ERLY MONDAY MORNING. RATHER WEAK PIECEMEAL
ENERGY ACRS WRN/CNTL MT EMANATING FM STRONGER SRN BC VORTEX TO
TRACK INTO CNTL MS VLY LATE DY2. PSBL MCS DVLPG ACRS KS/MO SUNDAY
EVENING WITH EWD MAINTENANCE PER RAMPING NOCTURNAL JETLET INTO
ECNTL MO OVERNIGHT. EWD PUSH OF EML MAY BE LIMITED PER MORE VEERED
FLOW WITH ERN EXTENT AND RELEGATE HIEST CHCS ACRS CNTL IL/CNTL IN
TOWARD DAYBREAK...AND HAVE OMITTED MENTION ACRS NRN CWA 06-12 UTC
MON.
LONG TERM... /MONDAY THROUGH FRIDAY.
IN COORDINATION WITH SHORT TERM PERIOD...HAVE OPTED TO LOWER POPS
MON/MON NGT GIVEN INCREASING SIGNALS FROM ECMWF AND GEFS OF LITTLE
OR NO PRECIP OCCURRING AS WEAK WAVE SET TO MOVE THROUGH LATE SUN
INTO MONDAY WILL BE SERIOUSLY LACKING ANY MSTR OR SIG
LIFT...LIMITING ITS EFFECTS MAINLY TO INCREASE IN MID LEVEL CLOUDS
AND MAYBE SOME LIGHT SHOWERS. SOMEWHAT STRONGER WAVES WILL MOVE
ACROSS THE NORTHERN/CENTRAL GREAT LAKES TUESDAY AND AGAIN THURSDAY.
WITH NW FLOW IN PLACE...MSTR WILL REMAIN CUT OFF WITH THESE SYSTEMS
AS WELL...BUT AT LEAST A BIT MORE IN THE WAY OF DYNAMICS WITH EACH
WAVE TO HANG ONTO CHC/SLGT CHC POPS...MAINLY IN NORTH AND EAST
SECTIONS.
WITH LITTLE CHANGE IN OVERALL FLOW...TEMPERATURES SHOULD REMAIN IN
THE 85 TO 90 DEGREE RANGE MUCH OF THE PERIOD WITH LOWER READING SEEN
WITH PASSAGE OF EACH WAVE AND ASSOCIATED CLOUDS/PRECIP. BY
FRIDAY...SLIGHTLY COOLER AIR MAY ARRIVE BEHIND THE THURSDAY
SYSTEM...BUT WILL ONLY SHAVE A FEW DEGREES OFF HIGHS COMPARED TO THE
REST OF THE WEEK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR INZ003.
MI...RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR MIZ077.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MURPHY
LONG TERM...FISHER
AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
224 PM MDT SAT JUL 28 2012
.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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1131 AM MDT SAT JUL 28 2012
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE PERIOD AT KGLD AND
KMCK. COLD FRONT JUST NW OF BOTH TERMINALS WILL DROP SOUTH OVER
THE NEXT FEW HOURS. THIS WILL ACT A FOCUS FOR ISOLATED TO
SCATTERED THUNDERSTORMS THIS AFTERNOON AND EVENING WITHING THE
VICINITY OF BOTH TERMINALS. CONFIDENCE IS STILL TOO LOW TO INCLUDE
ANYTHING OTHER THAN VCTS. GUSTY SW WINDS BETWEEN 10 AND 20 KT
CURRENTLY OVER BOTH TERMINALS WILL BECOME LIGHT AND VARIABLE AS
FRONT SHIFTS SOUTH AND GRADIENT DECREASES.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS JACKSON KY
137 PM EDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 136 PM EDT SAT JUL 28 2012
UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS. VORT LOBE SWINGING
ACROSS OH IS TRIGGERING ISOLATED SHOWERS AS FAR SW AS THE
KY...WV...OH TRI STATE REGION. EXPECT THESE TO STAY NE OF FORECAST
AREA. ALSO APPEARS A FEW SHOWERS MAY BE TRYING TO DEVELOP OVER SW VA.
FOR NOW WILL CONTINUE TO CARRY A THE SLIGHT CHANCE OF PRECIPITATION
IN OUR FAR SOUTHEAST.
UPDATE ISSUED AT 1121 AM EDT SAT JUL 28 2012
LATEST SATELLITE IMAGERY INDICATES EXTENSIVE CU/SC FIELD WILL AFFECT
THE FORECAST AREA THIS AFTERNOON...WITH PARTLY CLOUDY SKIES. HAVE
UPDATED NDFD FOR LATEST OBSERVATIONAL TRENDS.
UPDATE ISSUED AT 954 AM EDT SAT JUL 28 2012
OVERCAST LOW STRATUS ON SATELLITE IMAGERY THIS MORNING IN NORTHERN
PART OF FORECAST AREA AND IN SOUTHERN OH. BASED ON GOES CLOUD
THICKNESS PRODUCT THIS IS THINNING FAIRLY RAPIDLY. WAS AROUND 1200
FEET THICK AT 1215Z AND THINNING TO AROUND 600 FEET AT 1315Z. EXPECT
STRATUS TO CONTINUE TO THIN AND MIX OUT. ILN SOUNDING SHOWS FAIRLY
MOIST CONDITIONS UP TO 7OO MB AND AS LOW STRATUS MIXES OUT EXPECT CU
TO DEVELOP. HAVE MADE ADJUSTMENTS TO SKY COVER FORECAST TO ACCOUNT
FOR MORE CLOUD IN THE NORTH THIS MORNING...AND MORE CLOUD FOR THIS
AFTERNOON AS WELL AS CU FIELD DEVELOPS. SKY COVER HAS ALSO AFFECTED
THE DIURNAL TEMPERATURE RISE AND HAVE SLOWED THE RISE WHERE
CONDITIONS WILL BE MOSTLY CLOUDY THIS MORNING.
KEPT THE SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FAR
SOUTHEAST THIS AFTERNOON. THE 06Z GFS STILL SUPPORTS THIS
IDEA...WHILE THE 06Z NAM WOULD POINT TOWARDS DRY CONDITIONS.
INTERESTINGLY THE HRRR DEVELOPS SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS NEARLY THE ENTIRE FORECAST AREA THIS AFTERNOON. FEEL THIS IS
OVERDONE AND ONLY EXPECT A CU FIELD...NOT SCATTERED PRECIPITATION.
NDFD AND ZFP HAVE BEEN UPDATED.
UPDATE ISSUED AT 623 AM EDT SAT JUL 28 2012
FORECAST IS IN PRETTY GOOD SHAPE THIS MORNING WITH SKIES CONTINUING
TO CLEAR OFF. THERE IS SOME PATCHY MORNING FOG IN THE VALLEYS WHICH
WILL BE BURNING OFF SHORTLY AFTER SUNRISE. COLD FRONT IS CONTINUING
TO MAKE STEADY PROGRESS TO THE SOUTH AND EAST. LATEST 06Z NAM KEEPS
ALL THE CONVECTION SOUTHEAST OF THE AREA TODAY...BUT THE HRRR SHOWS
SOME HINTS AT SOME DEVELOPMENT IN THE SOUTHEAST AROUND MIDDAY.
THUS...GOING TO HANG ONTO THE SMALL CHANCE FOR SHOWERS AND
THUNDERSTORMS FOR THE TIME BEING. IT IS POSSIBLE EVERYTHING ENDS UP
FURTHER SOUTHEAST AND THE AREA STAYS COMPLETELY DRY TODAY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 308 AM EDT SAT JUL 28 2012
COLD FRONT IS QUICKLY DROPPING SOUTHEAST...VIRTUALLY ALIGNED WITH THE
OHIO RIVER PRESENTLY. COMPLEX OF SHOWERS AND STORMS CONTINUES TO ROLL
ACROSS AREAS NEAR THE TENNESSEE BORDER. BASED ON RADAR TRENDS...THIS
ACTIVITY SHOULD CONTINUE TO DIMINISH AND EXIT OVER THE NEXT
HOUR...LEAVING BEHIND DRY CONDITIONS FOR THE REMAINDER OF THE
MORNING. COLD FRONT WILL ROCKET SOUTHEAST THIS MORNING...REACHING THE
VIRGINIA/KENTUCKY BORDER BY MID MORNING. WITH MOISTURE POOLING AHEAD
OF THE FRONT...A FEW SHOWERS OR STORMS COULD DEVELOP IN THE VICINITY
OF THE VIRGINIA BORDER BY MIDDAY INTO THE EARLY AFTERNOON. THIS
SHOULD ONLY IMPACT A SLIVER OF EASTERN KENTUCKY. THE REST OF THE AREA
WILL REMAIN DRY TODAY. THERE IS MARGINAL WIND SHEAR PRESENT...BUT
SEVERE THREAT WILL LIKELY BE CONFINED TO AREAS FURTHER SOUTHEAST OF
KENTUCKY.
HIGH PRESSURE WILL CONTINUE TO DEVELOP OVER THE REGION TODAY THROUGH
TONIGHT...KEEPING QUIET WEATHER AROUND THROUGH THE REMAINDER OF THE
WEEKEND.
A VERY PLEASANT WEEKEND IS ON TAP AS SLIGHTLY COOLER AND A LESS HUMID
AIRMASS SPREAD INTO EASTERN KENTUCKY HIGHS TODAY AND SUNDAY WILL TOP
OUT IN THE MID 80S WITH LOWS IN THE MID 60S.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 445 AM EDT SAT JUL 28 2012
THE MODELS ARE IN DECENT AGREEMENT WITH THE GENERAL PATTERN ALOFT
THROUGH THE EXTENDED PORTION OF THE FORECAST. A SEMI-PERSISTENT TROUGH
WILL HOLD IN PLACE JUST TO THE NORTHEAST OF THE REGION THROUGH THE
MIDDLE OF NEXT WEEK. THIS WILL PROMOTE OCCASIONAL SHORTWAVES TO DROP
INTO THE OHIO VALLY ON NORTHWEST FLOW. A KEY ONE LOOKS TO MOVE
THROUGH LATE MONDAY. TOWARD THE END OF THE UPCOMING WORK WEEK THE
MODELS START TO DEVIATE FROM EACH OTHER WITH THE LATEST ECMWF PUSHING
THE WESTERN RIDGE FURTHER EAST AND FLATTENING OUT THE PATTERN
LOCALLY WHEN COMPARED TO THE GFS. ACCORDINGLY...PREFER A BLENDED
SOLUTION WHEN THE MODELS ARE CLOSE...BUT LEAN MORE TOWARD THE ECMWF
WHEN THEY START TO DEVIATE. DID HONOR THE SHORTWAVE THAT THE NAM12
AND THE 00Z ECMWF BRING DOWN INTO THE AREA MONDAY NIGHT AS A
POTENTIAL MCS...OTHERWISE PREFER AN EVEN MIX OF THE GFS AND ECMWF
FOR WEATHER SPECIFICS THROUGH MIDWEEK...LEANING MORE TOWARD THE
LATTER BY THE END OF THE WEEK. ALSO INCLUDED A GENEROUS DIURNAL
CYCLE TO THE POP PATTERN AND MAGNITUDE...THOUGH...AS THE PAST SEVERAL
NIGHTS HAVE SHOWN...THE CONVECTION HAS BEEN ABLE TO THRIVE WELL PAST
PEAK HEATING...IN OUR AREA.
SENSIBLE WEATHER WILL FEATURE HIGH PRESSURE HOLDING ON FOR A MOSTLY
DRY DAY ON MONDAY BEFORE A WARM FRONT APPROACHES FROM THE WEST
POSSIBLY YIELDING SOME LATE DAY STORMS. THESE STORM CHANCES WILL
CONTINUE THROUGH THE NIGHT AS A SHOT OF MID LEVEL ENERGY LOOKS TO
DIVE THROUGH THE STATE AFTER DARK IN THE NAM12...WITH CONSIDERABLE
SUPPORT FROM THE LATEST ECMWF. OTHERWISE...WITH A WEAK PRESSURE
FIELD THROUGHOUT THE REGION...NORTHWEST FLOW ALOFT...AND A HUMID
ENVIRONMENT...EXPECT THE DIURNAL INSTABILITY CYCLE TO DRIVE THE
CONVECTIVE CHANCES INTO THE END OF THE WEEK WITH PERHAPS ANOTHER
BOUNDARY MOVING INTO THE CWA LATE IN THE PERIOD IN RESPONSE TO
CHANGES ALOFT. TEMPERATURES WILL BE SEASONABLY WARM THROUGH THE
EXTENDED WITH PLENTY OF HUMIDITY KEEPING THE LOWS FAIRLY HIGH AND
CONDITIONS MUGGY EACH NIGHT.
THE CR EXTENDED GRID PACKAGE CAME IN REASONABLE FOR THE PATTERN...
THOUGH DID MAKE ADJUSTMENTS TO THE DIURNAL/TEMPORAL PATTERN OF
MAXIMUM AND MINIMUM POPS THROUGH THE PERIOD. MADE ONLY MINOR TWEAKS
TO LOW TEMPERATURES EACH NIGHT AS THE TERRAIN EFFECTS WILL BE RATHER
LIMITED GIVEN THE STILL MOIST ENVIRONMENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 136 PM EDT SAT JUL 28 2012
EXTENSIVE AREA OF SCT TO BKN CU/SC IS ACROSS THE REGION. CLOUD BASES
NEAR THE 3K FOOT ABOVE GROUND LEVEL...WITH SOME LOCAL MVFR CEILINGS
PRESENT. CLOUD BASES WILL CONTINUE TO LIFT THIS AFTERNOON WITH VFR
CONDITIONS PREVAILING.
HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT. CLOUDS WILL DECREASE
THIS EVENING...WITH MOSTLY CLEAR SKIES AND CALM WINDS SETTING THE
STAGE FOR FOG DEVELOPMENT TONIGHT. WITH THE EXCEPTION OF RIDGE TOP
AIRPORTS EXPECT IFR TO LIFR CONDITIONS TO DEVELOP. CONDITIONS WILL
IMPROVE AFTER SUNRISE ON SUNDAY...AND THERE SHOULD BE LESS EXTENSIVE
CU DEVELOPMENT LATE SUNDAY MORNING AND SUNDAY AFTERNOON. VFR
CONDITIONS WILL PREVAIL ONCE THE FOG DISSIPATES ON SUNDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...KAS
LONG TERM....GREIF
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS GLASGOW MT
237 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...
28/18Z...VFR CONDITIONS EXPECTED FOR THE MOST PART. ISOLATED TO
SCATTERED TSTMS ARE EXPECTED TO DEVELOP OR MOVE ACROSS NORTHEAST
MONTANA LATE THIS AFTN THROUGH MIDNIGHT. SYNOPTIC FEATURES AND
MESOSCALE MODELS SUPPORT THIS SCENARIO. FEEL PRETTY CONFIDENT ABOUT TIMING
AT TAF SITES...BUT LESS CONFIDENT ABOUT WHETHER ANY GIVEN TAF SITE
WILL EXPERIENCE A TSTM. SO AM JUST GOING TO CARRY A CB MENTION FOR
A TWO-HOUR WINDOW. MOYER
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
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.
&&
.PREV DISCUSSION... /ISSUED 1202 PM CDT SAT JUL 28 2012/
AVIATION...18Z KGRI TAF. VFR CEILING/VISIBILITY REMAINS IN THE
FORECAST FOR THE NEXT 24 HOURS...WITH MID LEVEL CLOUDS UNLIKELY TO
DROP BELOW 8000 FT EXCEPT POSSIBLY IN HIT OR MISS THUNDERSTORM
ACTIVITY. SPEAKING OF THIS THUNDERSTORM POSSIBILITY...CONFIDENCE
STILL REMAINS ON THE LOW SIDE WHETHER THE TERMINAL WILL BE
DIRECTLY IMPACTED...BUT JUST TO HINT AT THE POSSIBILITY OPTED TO
INTRODUCE A VICINITY THUNDERSTORM /VCTS/ MENTION COVERING A 5-HOUR
PERIOD FROM MID AFTERNOON INTO THIS EVENING. ALTHOUGH NOT
REFLECTED IN THE CURRENT TAF...ANY STORMS NEAR KGRI COULD INDUCE
SOME GUSTY/ERRATIC WINDS. OUTSIDE OF ANY STORMS...SURFACE WINDS
WILL PREVAIL FROM THE SOUTH THIS AFTERNOON...WITH GUST POTENTIAL
TO AROUND 21KT. OVERNIGHT...ANTICIPATE MORE OF A VARIABLE 6KT WIND
REGIME...WITH SOME LIGHT HAZE NOT OUT OF THE QUESTION...POSSIBLY
INDUCING VISIBILITY RESTRICTIONS DOWN TO AROUND 6SM BUT ABOVE MVFR
THRESHOLDS. AFTER SUNRISE SUNDAY MORNING...BREEZES WILL PICK UP
SLIGHTLY TO AROUND 11KT FROM THE NORTH-NORTHEAST BEHIND A WEAK
COLD FRONT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...PFANNKUCH
LONG TERM...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1202 PM CDT SAT JUL 28 2012
.UPDATE...PRIMARY CHALLENGE FOR THIS AFTERNOON/EVENING CONTINUES
TO BE HOW MUCH THUNDERSTORM ACTIVITY WILL DEVELOP...FOLLOWED BY
HOW CLOSE PARTS OF THE SOUTHWEST CWA WILL GET TO REACHING CRITICAL
FIRE WEATHER THRESHOLDS. IN SHORT...HAVE CHANGED VERY LITTLE OF
NOTE FROM THE PREVIOUS FORECAST...OTHER THAN DELAYING ANY RISK OF
CONVECTION TO AFTER 20Z INSTEAD OF THE PREVIOUSLY ADVERTISED 18Z.
STILL KEPT POPS AT NO MORE THAN 30 PERCENT FOR THIS EVENT GIVEN
UNCERTAINTY IN COVERAGE...AT LEAST FOR NOW. DETERMINISTIC AND HIGH
RES QPF FIELDS HAVE BEEN ALL OVER THE PLACE THIS MORNING...BUT
WITH THE HRRR FINALLY ACKNOWLEDGING THAT MOST ACTIVITY SHOULD HOLD
OFF UNTIL THE MID- LATE AFTERNOON HOURS VERSUS EARLY AFTERNOON. AT
THE SURFACE...THE PRIMARY INITIAL FOCUS FOR AFTERNOON/EVENING
CONVECTION LOOKS TO BE A SURFACE TROUGH CURRENTLY SETTING UP ALONG
A LINE FROM NORTH CENTRAL TO SOUTHWEST NEB. ALTHOUGH WATER VAPOR
IMAGERY INDICATES NO WELL-DEFINED DISTURBANCES HEADING OUR
WAY...SUBTLE SHORTWAVE ENERGY EMBEDDED IN THE NEARLY ZONAL FLOW
SHOULD BE ENOUGH TO KICK OFF STORMS...ESPECIALLY AS AT LEAST
1000-1500 J/KG 0-1KM MLCAPE WEAKENS THE CAP IN THE VICINITY OF THE
SURFACE TROUGH. GIVEN FAIRLY WELL-MIXED BOUNDARY LAYER ANTICIPATE
INITIAL STORMS ACROSS THE NORTHERN/WESTERN CWA TO STEADILY
PROPAGATE EAST- SOUTHEAST...AND POSSIBLY TAKE ON A QUASI-LINEAR
CONFIGURATION. ALTHOUGH INSTABILITY IS NOT LOOKING OVERLY
HIGH...AT LEAST BRIEF GENERALLY HIGH BASED SUPERCELL STRUCTURES
CANNOT BE RULED OUT GIVEN 30-40KT OF DEEP LAYER SHEAR. EARLIER
THIS MORNING SPC UPGRADED MUCH OF THE NORTHERN 1/2 OF THE CWA TO A
SLIGHT RISK...AND FROM A LOCAL FORECAST PERSPECTIVE...FEEL THAT AT
LEAST A BRIEF SEVERE WEATHER THREAT PROBABLY CANNOT BE RULED OUT
ANYWHERE WITHIN THE CWA THROUGH THIS EVENING. REGARDING OTHER
ELEMENTS OF TODAYS FORECAST...MADE VERY LITTLE CHANGE TO HIGH TEMP
FORECAST...BUT DID LOWER SOME NORTHEAST COUNTIES A FEW DEGREES
GETTING THEM MORE SO INTO THE 92-94 RANGE. OTHERWISE...UPPER 90S
TO AROUND 105 STILL APPEAR ON TRACK IN KS ZONES...AND AS MENTIONED
BY OVERNIGHT SHIFT...IT COULD BE A VERY CLOSE CALL WHETHER SOME
SOUTHWESTERN COUNTIES MEET CRITICAL FIRE WEATHER CRITERIA THIS
AFTERNOON. WILL CONTINUE TO MONITOR BUT NO FIRE WEATHER HEADLINES
PLANNED AT THIS TIME.
&&
.AVIATION...18Z KGRI TAF. VFR CEILING/VISIBILITY REMAINS IN THE
FORECAST FOR THE NEXT 24 HOURS...WITH MID LEVEL CLOUDS UNLIKELY TO
DROP BELOW 8000 FT EXCEPT POSSIBLY IN HIT OR MISS THUNDERSTORM
ACTIVITY. SPEAKING OF THIS THUNDERSTORM POSSIBILITY...CONFIDENCE
STILL REMAINS ON THE LOW SIDE WHETHER THE TERMINAL WILL BE
DIRECTLY IMPACTED...BUT JUST TO HINT AT THE POSSIBILITY OPTED TO
INTRODUCE A VICINITY THUNDERSTORM /VCTS/ MENTION COVERING A 5-HOUR
PERIOD FROM MID AFTERNOON INTO THIS EVENING. ALTHOUGH NOT
REFLECTED IN THE CURRENT TAF...ANY STORMS NEAR KGRI COULD INDUCE
SOME GUSTY/ERRATIC WINDS. OUTSIDE OF ANY STORMS...SURFACE WINDS
WILL PREVAIL FROM THE SOUTH THIS AFTERNOON...WITH GUST POTENTIAL
TO AROUND 21KT. OVERNIGHT...ANTICIPATE MORE OF A VARIABLE 6KT WIND
REGIME...WITH SOME LIGHT HAZE NOT OUT OF THE QUESTION...POSSIBLY
INDUCING VISIBILITY RESTRICTIONS DOWN TO AROUND 6SM BUT ABOVE MVFR
THRESHOLDS. AFTER SUNRISE SUNDAY MORNING...BREEZES WILL PICK UP
SLIGHTLY TO AROUND 11KT FROM THE NORTH-NORTHEAST BEHIND A WEAK
COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 440 AM CDT SAT JUL 28 2012/
SHORT TERM...TODAY THROUGH MONDAY NIGHT. MULTIPLE FORECAST
CONCERNS...ESP TODAY AND SUNDAY...INCLUDING
TEMPERATURES...PRECIP CHANCES...AND FIRE WEATHER ISSUES.
SATELLITE AND UPPER LEVEL PROFILER DATA CONTINUE TO SHOW THE
REGION UNDER THE INFLUENCE OF HIGH PRESSURE/RIDGING CENTERED
OVER THE SRN PLAINS...WHILE A WEAK DISTURBANCE CONTINUES TO RIDE
AROUND THE EDGE OF THE RIDGE...CURRENTLY OVER NERN NEB/SERN SD.
ANOTHER DISTURBANCE IS CURRENTLY MAKING ITS WAY THROUGH WY...WHICH
CAN ALSO BE PICKED OUT VIA LIGHTNING DATA. WAS CONCERNED LAST
NIGHT THAT THE ACTIVITY MAY STAY JUST NORTH OF THE CWA...AND AT
THIS POINT...LOOKS LIKE HOW IT IS GOING TO TURN OUT. AT THE
SURFACE...THE CWA SITS BETWEEN HIGH PRESSURE EXTENDING FROM NRN IA
INTO ERN CANADA...AND LOW PRESSURE DRAPED ALONG THE HIGH/SRN
PLAINS...BRINGING SOUTHEASTERLY FLOW...WITH SPEEDS GENERALLY
NEAR/LESS THAN 10 MPH.
LOOKING TO THE REST OF TODAY AND INTO TONIGHT...CONTINUE TO SEE
THE POTENTIAL FOR THUNDERSTORM ACTIVITY ACROSS THE
CWA...PRIMARILY THIS AFTERNOON/EVENING. EVEN THIS CLOSE IN
TIME...PLENTY OF MODEL DIFFERENCES REMAIN. THE GENERAL STORY LIES
WITH THAT NEXT DISTURBANCE MOVING ONTO THE PLAINS...WHICH LOOKS TO
SPARK OFF THUNDERSTORMS ACROSS THE REGION. A SURFACE TROUGH AXIS
IS EXPECTED TO PUSH SOUTH THROUGH THE DAY...BUT WHERE IT EXACTLY
ENDS UP CONTINUES TO BE DEBATED BETWEEN MODELS. THE NAM REMAINS ON
THE MORE AGGRESSIVE SIDE OF THINGS WITH THE THUNDERSTORM
DEVELOPMENT...WITH THE GFS/EC SHOWING VERY LITTLE. WITH SUPPORT
FROM THE 00Z 4KM WRF AND HRRR ALSO TRENDED MORE TOWARD THE NAM
/BUT NOT NEARLY AS WIDESPREAD/...DECIDED TO UP POPS INTO THE 30
PERCENT RANGE...MAINLY ACROSS SC NEB. DIDNT RAISE ANY HIGHER DUE
TO THOUGHT THAT THE NAMS COVERAGE COULD BE OVERDONE. DID KEEP
LINGERING POPS INTO THIS EVENING...BUT EXPECT THINGS TO BE WINDING
DOWN PRIOR TO MIDNIGHT. AS FAR AS SEVERE WEATHER GOES...FEEL THAT
WHAT THUNDERSTORMS DO DEVELOP LATER TODAY COULD BE CAPABLE OF
DAMAGING WINDS...WITH FORECAST SOUNDINGS SHOWING GOOD MIXING
POTENTIAL AND PLENTY OF DRIER AIR IN THE LOWER LEVELS. WILL GO
AHEAD AND INSERT THAT POSSIBILITY IN THE HWO. COULDNT RULE OUT
SOME QUARTER SIZE HAIL...BUT WINDS LOOK TO BE MORE A THREAT.
AS FAR AS TEMPERATURES GO...ONLY MINOR ADJUSTMENTS WERE MADE...AND
STILL EXPECTED TO BE WARMER THAN FRIDAY...AS WARMER AIR ALOFT
CONTINUES TO BUILD IN FROM THE WEST. FORECAST CURRENTLY CALLING
FOR MID 90S IN THE NORTHEAST TO 100-105 ACROSS THE SW CORNER OF
THE CWA. AS MENTIONED ABOVE...FORECAST SOUNDINGS /ESP IN THE SW/
SHOW GOOD MIXING POTENTIAL...AND AFTERNOON DEWPOINTS REFLECT THAT
POSSIBILITY. COMBINED WITH THE EXPECTED INCREASINGLY MORE
SOUTHWESTERLY COMPONENT TO THE WINDS...BY MID
AFTERNOON...EXPECTING TO SEE DEWPOINTS IN THOSE SOUTHWESTERN
LOCATIONS FALL INTO THE LOWER 50S...WHILE LOCATIONS GENERALLY
ALONG/NORTH OF I80 LOOK TO REMAIN CLOSER TO THE LOWER 60 PERCENT
RANGE. DID NOT GO WITH ANY HEAT ADV HEADLINE FOR TODAY ACROSS NC
KS /WHERE HIGHS ARE HOTTEST/...AS THE LOWER DEWPOINTS EXPECTED TO
ACCOMPANY THOSE TEMPERATURES SHOULD KEEP HEAT INDEX VALUES FROM
EXCEEDING 105 DEGREES ON A WIDESPREAD BASIS.
FORECAST FOR TODAY DID RAISE SOME CONCERNS ABOUT FIRE
WEATHER...SEE FIRE SECTION BELOW FOR MORE INFORMATION.
AS WE GET INTO SUNDAY/SUNDAY NIGHT...THUNDERSTORM CHANCES REMAIN
IN THE FORECAST. KEPT THE MORNING HOURS DRY...BUT AS THIS LATEST
DISTURBANCE MOVES THROUGH AND EVENTUALLY EAST OF THE CWA...MODELS
HAVE COME INTO BETTER AGREEMENT SHOWING THE SURFACE BOUNDARY
PUSHING FURTHER SOUTH THROUGH THE CWA...EVENTUALLY SETTLING AT
LEAST NEAR THE NEB/KS STATE LINE...IF NOT FURTHER SOUTH. DEPENDS
ON THE MODEL. HAVE SOME LOW POPS IN DURING THE AFTERNOON ACROSS
SOUTHERN PORTIONS OF THE CWA...CLOSE TO WEAR THE BOUNDARY COULD
BE. MADE LITTLE CHANGE TO THE EVENING/OVERNIGHT POPS...THE GFS
CONTINUES TO CERTAINLY BE ON THE MORE WIDESPREAD SIDE OF
THINGS...BUT FORECAST REMAINS TRENDED TOWARDS BETTER SUPPORT
JUSTIFYING LOWER POPS. MODELS SHOW AN INCREASE IN TEMPERATURES
ALOFT ACROSS THE REGION ON SUNDAY...BUT WITH THE MORE EASTERLY
COMPONENT TO THE WINDS...HARD TO GO MORE THAN A COUPLE OF DEGREES
WARMER THAN TODAY /DIDNT MAKE NOTABLE CHANGES TO THE INHERITED
TEMPERATURES/. AM CONCERNED THAT THOSE EASTERLY WINDS ARE GOING
HAVE A GREATER IMPACT ON THE TEMPERATURES /PRIMARILY ACROSS SC
NEB/...AND UPCOMING SHIFTS WILL HAVE TO TAKE A LOOK AT THAT. IF
THE BOUNDARY DOESNT GET AS FAR SOUTH AS SAY THE 06Z NAM
SUGGESTS...WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR HEAT ADV
CRITERIA ACROSS NC KS. AT THIS TIME...WITH PLENTY OF UNCERTAINTY
WASNT GOING TO GO DOWN THAT ROAD.
UNCERTAINTY WITH THE PRECIPITATION CHANCES CONTINUES INTO
MONDAY...AND KEPT LOW POPS IN PLACE ACROSS THE CWA. MODELS RANGE
FROM VERY LITTLE GOING ON ANYWHERE...TO WIDESPREAD ACTIVITY ACROSS
PORTIONS OF SC NEB...TO ACTIVITY DRIFTING INTO THE WEST FROM
EARLIER DEVELOPMENT ACROSS THE HIGH PLAINS. CANT REALLY NAIL
DOWN BETTER SPECIFICS WITH THE POPS UNTIL THERE IS BETTER
AGREEMENT WITH ANY SOLUTION BETWEEN THE MODELS. THERE IS BETTER
AGREEMENT IN REGARD TO TEMPERATURES...WHICH SHOW HIGHS BEING
COOLER THAN ON SUNDAY...WITH LOWER/MID 90S IN NEB...MID/UPPER 90S
IN KS. KEPT THE INHERITED DRY FORECAST FOR MONDAY NIGHT IN PLACE.
LONG TERM...TUESDAY THROUGH FRIDAY.
THE MAIN CONCERN FOR THE LONG TERM PERIOD WILL AGAIN FOCUS ON
CHANCES FOR SHOWERS AND THUNDERSTORMS. OTHERWISE...MADE VERY FEW
CHANGES TO THE EXTENDED.
WHILE AN UPPER LEVEL RIDGE REMAINS STEADFAST ACROSS THE WESTERN
TWO THIRDS OF THE CONUS TOWARDS THE BEGINNING OF THE LONG
TERM...AN UPPER LEVEL TROUGH OFF THE WESTERN COAST SLOWLY BEGINS
TO PUSH EASTWARD ACROSS CANADA...THUS HELPING BREAK DOWN THE UPPER
LEVEL RIDGE. IN ADDITION...NUMEROUS SHORT WAVES CONTINUE TO ROUND
THE TOP OF THE UPPER LEVEL RIDGE AND SKIRT ACROSS THE PLAINS.
ALTHOUGH TIMING AND PLACEMENT AS WELL AS RESOLUTION REMAIN
INCONSISTENT AMONG THE LONG TERM MODELS...THERE APPEARS TO BE SOME
CHANCE AT AN UPPER LEVEL DISTURBANCE PASSING THROUGH THE REGION
SOMETIME DURING THE LONG TERM PERIOD. AT THE SURFACE...LOW
PRESSURE ALONG THE NORTHERN ROCKIES IS EXPECTED TO SHIFT EASTWARD
ACROSS THE DAKOTAS...WHILE HIGH PRESSURE REMAINS SITUATED ACROSS
THE CENTRAL PLAINS...THROUGH AT LEAST THURSDAY MORNING. DEVELOPING
LOW PRESSURE ACROSS THE REGION ON THURSDAY...COMBINED WITH THE
POSSIBILITY OF AN UPPER LEVEL SHORT WAVE AND UPPER LEVEL JET
STREAK COULD CERTAINLY GENERATE SOME POPS ACROSS THE AREA. AT THIS
POINT...MODELS REMAIN TOO INCONSISTENT TO CONTINUE WITH SEVERAL
PERIODS OF SLIGHT CHANCE POPS. PER NEIGHBOR
COLLABORATION...CONTINUED A DRY FORECAST THROUGH MUCH OF THE
EXTENDED WITH THE EXCEPTION OF FRIDAY. FOR FRIDAY...MODELS ARE AT
LEAST IN AGREEMENT ON PLACEMENT OF A SURFACE LOW/TROUGH ALONG THE
HIGH PLAINS SHIFTING EASTWARD...AN UPPER LEVEL JET ACROSS PORTIONS
OF NEBRASKA...AND A WEAK UPPER LEVEL WAVE TRAVERSING THE REGION.
THUS ADDED SLIGHT CHANCES FOR POPS TO MOST OF THE OUTLOOK AREA ON
FRIDAY.
FIRE WEATHER...MAIN CONCERN IS GOING TO LIE ACROSS THE
SOUTHWESTERN THIRD OF THE CWA...WHERE THE BETTER MIXING
POTENTIAL...AND THUS LOWER DEWPOINTS AND HIGHER TEMPERATURES WILL
EXIST. DEBATED ISSUING A HEADLINE FOR PORTIONS OF NC KS THIS
AFTERNOON...AS FORECAST RELATIVE HUMIDITY VALUES ARE EXPECTED TO
FALL TO NEAR/JUST BELOW 20 PERCENT. THE LIMITING FACTOR LIES WITH
THE WINDS. THE MAJORITY OF MODEL DATA AND GUIDANCE KEEPS SUSTAINED
WIND SPEEDS BELOW CRITICAL LEVELS...AND FORECAST SOUNDINGS SHOW
THE HIGHER WINDS ALOFT/GUST POTENTIAL HAPPENING EARLIER IN THE
AFTERNOON...BEFORE THE RH VALUES DROP. CONFIDENCE IN THE WIND/WIND
GUST AND RH CRITERIA BOTH BEING MET FOR 3 HOURS WAS LOW ENOUGH TO
NOT ISSUE A HEADLINE. HOWEVER...IT WILL BE SOMETHING FOR THE DAY
SHIFT CREW TO KEEP A CLOSE EYE ON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/AVIATION...PFANNKUCH
SHORT TERM/FIRE WEATHER...ADO
LONG TERM...SALTZMAN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
359 PM CDT SAT JUL 28 2012
.SHORT TERM...NOW THROUGH SUNDAY MORNING...
THE MAIN PROBLEM OF THE DAY IS WITH TIMING AND COVERAGE OF
PRECIPITATION WITH SEVERAL MIDDLE LEVEL IMPULSES OVER CONUS
NOW AIMED AT NORTH DAKOTA...PER WATER VAPOR SATELLITE IMAGERY.
SHOWERS AND THUNDERSTORMS ARE MAINTAINING COVERAGE AND INTENSITY
ALONG I94 CORRIDOR PER 20 UTC RADAR IMAGERY. THE PERSISTENCE OF
THIS FEATURE/CONVECTION OUTLINES THE LOW PREDICTABILITY
ASSOCIATED WITH WEAK MIDDLE LEVEL SHORTWAVES MOVING OVER A CAPPED
AND MODESTLY CONVECTIVELY UNSTABLE ENVIRONMENT. AS A RESULT OF
MAINTENANCE...FORECAST GRIDS HAVE BEEN REACTIVELY UPDATED TO
REFLECT EASTWARD PROPAGATION THROUGH MIDNIGHT.
CURRENT RADAR IMAGERY ALSO INDICATES A STRONG/SEVERE THUNDERSTORM
PRESENTLY OVER SOUTHEASTERN SASKATCHEWAN IS RIGHT MOVING TOWARD
DIVIDE COUNTY...AND SHOULD BE ENTERING THE AREA BY 5 PM CDT. THERE
MAY BE SUFFICIENTLY-DEFINED DYNAMIC SUPPORT MECHANISM FOR A SEVERE
WEATHER THREAT THIS EVENING. TRENDS WILL BE MONITORED.
THE 16 AND 17 UTC HRRR BOTH SUPPORT CONVECTION FORMING SOON AND
IMPACTING NORTHERN NORTH DAKOTA UNTIL JUST AFTER SUNSET. THEY THEN
DIRECT ADDITIONAL CONVECTION INTO WESTERN NORTH DAKOTA TONIGHT AS
THE IMPULSE OVER SOUTHWESTERN MONTANA ADVECTS EASTWARD.
THEREAFTER...SEVERAL SHORTWAVES ARE FORECAST TO MOVE ACROSS THE
DAKOTAS...BUT PREDICTABILITY IS LOW. FORECASTS REFLECT A BLEND OF
09 UTC SREF MEAN WITH ASSORTED MOS GUIDANCE.
TEMPERATURES WILL GENERALLY REMAIN ABOVE AVERAGE THROUGH THE
PERIOD.
.LONG TERM...MONDAY THROUGH SATURDAY...
THE WESTERN ROCKIES AND HIGH PLAINS RIDGE REMAINS QUITE STRONG
THROUGH THE FIRST PART OF THE EXTENDED PERIOD WITH PERIODIC CLOSED
LOWS AND SHORTWAVES TOPPING RIDGE BRINGING EPISODES OF THUNDERSTORMS
TO THE FORECAST AREA.
ON MONDAY THE UPPER RIDGE IS WEST OF THE FORECAST AREA...AND WE HAVE
NORTHWEST FLOW ALOFT OVER THE STATE WITH A COOL AND DRY SURFACE HIGH
PRESSURE SYSTEM OVER MANITOBA/MINNESOTA/EASTERN DAKOTAS WHICH SHOULD
KEEP THE AREA FREE FROM CONVECTION.
HOWEVER MONDAY NIGHT AND TUESDAY THE UPPER LEVEL RIDGE MOVES EAST
INTO THE DAKOTAS WITH THE LEADING EDGE OF A CLUSTER OF SHORTWAVE
IMPULSES. A SURFACE LOW/TROUGH THAT DEVELOPS IN RESPONSE IN THE LEE
OF THE ROCKIES MOVES INTO THE WESTERN DAKOTAS DURING THE DAY
TUESDAY. THUS HAVE RAISED CHANCES OF THUNDERSTORMS FOR MONDAY NIGHT
AND TUESDAY A BIT.
TUESDAY NIGHT THROUGH THURSDAY THE TIMING OF SHORT WAVES IS
DIFFICULT AND CONFIDENCE LOW IN PRECIPITATION CHANCES. THUS SPOTTY
SLIGHT CHANCES OF PRECIPITATION THESE TIME PERIODS.
LATE IN THE EXTENDED PERIOD...BEGINNING THURSDAY NIGHT...THE UPPER
LEVEL RIDGE FLATTENS AS A STRONGER SYSTEM ROTATES AROUND HUDSON BAY
LOW AND AND SECONDARY CLOSED FORMS OVER THE CANADIAN PRAIRIE
PROVINCES BRINGING COOLER TEMPERATURES AND INCREASED CHANCES OF
PRECIPITATION TO THE NORTHERN PLAINS.
HIGH TEMPERATURES IN THE MID 80S TO MID 90S FOR MONDAY THROUGH
WEDNESDAY...THEN A COOLING TREND AT THE END OF THE WEEK AS THE
AFOREMENTIONED UPPER LEVEL LOW FROM THE CANADIAN PRAIRIES MOVES
ACROSS THE FORECAST AREA.
&&
.AVIATION...
LARGE AREA OF SHOWERS AND ISOLATED TSTMS AROUND KBIS AND SOUTH TO
THE SD BORDER SHOULD MOVE EWD AND AFFECT KJMS AFT 23Z. TSTMS HAD
DEVELOPED OVER S CENTRAL SASK AND WERE MOVING SEWD...LIKELY
ASSOCIATED WITH A DISTURBANCE THAT IS FORECAST TO MOVE E/SE ACROSS
THE NRN TIER OF COUNTIES - MAINLY N OF KISN...BUT MAY AFFECT KMOT
TAF SITE. LATER TAF ISSUANCES TO PINPOINT BETTER CONFIDENCE IN
TIMING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION....JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
101 PM CDT SAT JUL 28 2012
.DISCUSSION...
ONGOING SHOWERS ARE EXPANDING IN COVERAGE PER RADAR IMAGERY...AND
LIGHTENING OVERLAY SHOWS A FEW LIGHTENING STRIKES EVERY HOUR OR SO.
THESE TRENDS SUGGEST THAT A BLEND OF THE 09 UTC SREF MEAN AND 15
UTC HRRR WILL BE BEST IN THE SHORT TERM FOR PRECIPITATION CHANCES.
THUS...UPDATED FORECAST INDICATES MUCH GREATER CHANCES ALONG I94
CORRIDOR. CLOUD GRIDS HAVE ALSO BEEN UPDATED TO REFLECT THESE
TRENDS.
THE MAIN PROBLEM OF THE DAY IS WITH TIMING AND COVERAGE OF
PRECIPITATION AS AT LEAST FOUR MIDDLE LEVEL IMPULSES OVER CONUS
ARE AIMED AT NORTH DAKOTA.
&&
.AVIATION...
18Z TAF ISSUANCE...RATHER LARGE AREA OF SHOWERS BETWEEN KDIK AND
KBIS IS MOVING WEST TO EAST. 18Z-00Z ONLY ISOLATED/SCATTERED
CONVECTION EXPECTED. DID NOT MENTION VCTS OR VCSH IN TAFS AFT
00Z...MAINLY WITH EXPECTATION OF ANOTHER DISTURBANCE ACROSS THE
NRN TIER OF COUNTIES - MAINLY NORTH OF KISN/KMOT. KJMS MAY SEE
VCTS IN LATER ISSUANCE AS WELL. LATER TAF ISSUANCES TO PINPOINT
BETTER CONFIDENCE IN TIMING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...SCHECK
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1136 AM CDT SAT JUL 28 2012
.DISCUSSION...EARLY CONVECTIVE THREAT HAS SLID MAINLY ACROSS EASTERN
SD INTO SWRN MN... MISSING THE SOUTHERN RRV ENTIRELY. MEANWHILE...
SCATTERED MID TO UPPER LVL CLOUDS ACROSS THE FA HAVE SLOWED THE
HEATING CURVE A BIT. EXPECT MAX TEMPS TO STILL REACH MID 80S IN MOST
LOCATIONS.
A DEVELOPING CONVECTIVE AREA IN WESTERN ND IS LIFTING TOWARDS CNTRL
ND ATTM AND STILL HAS POTENTIAL TO EXPAND INTO ERN ND THROUGH LATE
AFTERNOON AS PER CURRENT RAP GUIDANCE. CURRENT SHREF AND NAM
SOLUTIONS TEND TO SHEAR AND DIMINISH THIS IMPULSE... WHILE FAVORING
A LATER AND MORE NORTHERLY TRACKING IMPULSE /NOW MOVING ACROSS SRN
SASK/ FOR SOME EVENING AND OVERNIGHT CONVECTIVE THREAT.
&&
.AVIATION...
SCATTERED MID TO UPPER LEVEL CLOUDS AND LIGHT TO MODERATE SOUTHERLY
WINDS EXPECTED THROUGH THE AFTERNOON AND EARLY EVENING. ISOLATED
SHOWERS AND THUNDERSTORMS POSSIBLE LATE EVENING IN EASTERN ND AND
OVERNIGHT INTO NWR MN.
&&
.PREVIOUS DISCUSSION.../ISSUED 346 AM CDT SAT JUL 28 2012/
LARGE SCALE PATTERN WILL UNDERGO LITTLE CHANGE THROUGH THIS
PERIOD. WATER VAPOR IMAGERY INDICATES MULTIPLE SHORTWAVES THAT
COULD BRING THUNDER CHANCES TO THE REGION OVER THE NEXT COUPLE
DAYS. ONE SUCH WAVE BRINGS SHOWER/THUNDER CHANCES TO THE SW FA
THIS MORNING. THERE IS ANOTHER SHORTWAVE IN WESTERN MONTANA (AT
08Z) THAT SHOULD TRACK ALONG OR JUST NORTH OF THE INTERNATIONAL
BORDER TODAY INTO TONIGHT. DEPENDING ON EXACT TIMING AND
LOCATION...THIS COULD PROVIDE ENOUGH FORCING FOR SCATTERED THUNDER
ACROSS THE NORTHERN FA MAINLY TONIGHT. MODELS INDICATE INCREASING
850MB CAPE AND 0-6KM DEEP LAYER SHEAR OF 30-35 KNOTS...WHICH COULD
LEAD TO A FEW STRONGER STORMS. LOW LEVEL JET IS WEAK...AND COVERAGE
SHOULD BE LIMITED.
A STRONGER SHORTWAVE CURRENTLY (08Z) ACROSS SOUTHWEST CANADA WILL
ROUND THE UPPER RIDGE AND TRACK INTO NORTHERN MINNESOTA BY 06Z
MONDAY...SENDING A COLD FRONT THROUGH THE REGION SUNDAY
AFTERNOON/EVENING. STRONGEST FORCING AND BEST STORM COVERAGE
SHOULD BE ACROSS THE NORTHERN FA. DEEP LAYER SHEAR WILL BE AOA 40
KNOTS ACROSS THE NORTH...AND MLCAPE VALUES COULD BE MODERATE. THE
MAIN QUESTION FOR SEVERE POTENTIAL WILL BE TIMING OF THE UPPER
WAVE (AND STRONGEST FORCING). SUNDAY AFTERNOON AND EVENING HAS THE
POTENTIAL TO BE BUSY (ESPECIALLY ACROSS THE NORTHERN FA).
LOW-LEVEL RIDGING AND A DRIER AIRMASS WILL MOVE INTO THE REGION ON
MONDAY.
TEMPERATURES WILL BE BACK TO SLIGHTLY ABOVE NORMAL VALUES...WITH
THE WARMEST DAY BEING SUNDAY AS MAX TEMPS SHOULD BE ABLE TO RISE
INTO THE 90S AHEAD OF THE STRONGER WAVE.
LONG TERM (TUESDAY-FRIDAY)...MODELS IN GENERAL AGREEMENT THAT START
OF EXTENDED WILL BE RELATIVELY RAIN FREE AS SURFACE HIGH PRESSURE
BUILDS IN BEHIND DEPARTING FRONT. RETURN FLOW DEVELOPS TUESDAY
SETTING THE STAGE FOR NEXT SIGNIFICANT THREAT FOR SHOWERS AND
STORMS. DGEX APPEARS TO BE ODD MODEL OUT WITH WHAT LOOKS LIKE AN MCS
12Z-18Z TUESDAY...ALTHOUGH GEM-NH ABOUT 12 HOURS SLOWER ON SIMILAR
TRACK ACROSS SOUTHERN RRV.
FROM THE MASS FIELDS STANDPOINT THERE IS SUPPORT FOR TSRA WITH 850
MOIST FLUX DIV...700 WAA AND 250MB DIVERGENCE SUGGESTING ELEVATED
CONVECTION POSSIBLE. ALLBLEND SUPPORT THE SLOWER SOLUTION IN THE
00Z - 12Z WEDNESDAY TIME PERIOD...WHICH IS IN LINE WITH THE GFS
AND ECMWF SOLUTIONS AS WELL.
TEMPERATURES REMAIN WELL ABOVE NORMAL TUESDAY - WEDNESDAY AS UPPER
RIDGE MAINTAINS AND LITTLE IN THE WAY OF IMMEDIATE COOLING BEHIND
WIND-SHIFT FORECAST IN THE EARLY THURSDAY TIME FRAME. LIKE THE
SLOWER ECMWF...BUT NET RESULT SIMILAR IN THAT COOLER AIR FOR
THURSDAY AND FRIDAY BRINGING TEMPERATURES DOWN TO NEAR EARLY AUGUST
NORMALS.
LATE PERIOD RETURN FLOW SETS THE STAGE AGAIN FOR THREAT OF
CONVECTION AS LARGE SCALE PATTERN SUPPORTS ENERGETIC WEST/NORTHWEST
FLOW INTO THE PLAINS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GUST/WB/JAM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
349 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 /20Z SATURDAY THROUGH THURSDAY/...
DID NOT CHANGE MUCH WITH THE FORECAST TODAY. CLEARED OUT THE CU
FIELD QUICKLY THIS EVENING. NORTH WINDS UNDER 5KT WILL HELP LIMIT
ANY BR TO MAINLY OCCUR WITH THE COOLEST PERIOD OF THE OVERNIGHT
9-12Z AND MAINLY BE MVFR. EXCEPTION HERE IS KLUK WHERE THE COLD
POOL WILL PROBABLY SOCK THEM IN WITH A LOW CIG AND NEAR ZERO VSBYS.
CU FIELD WILL BE A GOOD BIT LESS TOMORROW AS THE AIRMASS MODIFIES
AND SOME H8 HEATING IS EXPECTED THROUGH THE DAY. VARIABLE WINDS
WILL WORK IN LATE IN THE PERIOD AS THE SURFACE HIGH MAINTAINS A
CLOSE IF NOT NEBULOUS PROXIMITY TO THE REGION.
.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...FRANKS
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1033 AM PDT Sat Jul 28 2012
.SYNOPSIS...
A trough of low pressure off the coast will keep a southwest to
northeast oriented storm track in the vicinity of Eastern
Washington and North Idaho into next week. This pattern should
result in near normal temperatures through around mid week. A cooler
and more showery weather pattern may develop late next week as the
offshore low moves inland.
&&
.DISCUSSION...
Morning Update: We have removed thunderstorm chances over the Blue
Mtns and Camas Prairie for this afternoon. Drier W flow in the
wake of last night`s shortwave passage has brought surface
dewpoints down into the 30`s to low 40`s Fahrenheit. Forecast
soundings plotted over these locations via the NAM/GFS strongly
agree that the CIN (convective inhibition) will be overwhelming
this afternoon and local HRRR is in strong agreement. Otherwise,
the forecast is on track with sunny skies and seasonal
temperatures expected region-wide with the exception of fair
cumulus fields speckled across the northern mountains. /sb
&&
.AVIATION...
18Z TAFS...Weak high pressure will promote mainly clear and dry
conditions at TAF sites, with VFR conditions, and light winds.
/sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 83 58 86 61 87 61 / 0 0 0 10 0 0
Coeur d`Alene 82 53 84 56 85 56 / 0 0 0 10 10 0
Pullman 82 52 84 54 85 54 / 0 0 0 10 10 10
Lewiston 91 62 93 65 93 63 / 0 0 10 10 10 10
Colville 86 55 88 56 91 55 / 0 0 0 10 10 10
Sandpoint 84 47 82 50 83 52 / 0 0 0 10 10 10
Kellogg 81 51 84 54 85 54 / 0 0 0 10 10 10
Moses Lake 86 59 89 60 90 58 / 0 0 0 0 0 0
Wenatchee 87 63 89 63 90 62 / 0 0 0 0 0 0
Omak 88 58 90 58 91 58 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1158 AM CDT SAT JUL 28 2012
.UPDATE...
AREA OF SHOWERS/STORMS OVER IOWA ASSOCIATED WITH MESOSCALE SHORTWAVE
SHOULD CONTINUE TO MOVE SOUTHEAST AS WAVE TRAVELS AROUND MID-UPPER
LEVEL RIDGE OVER SOUTHERN PLAINS. EARLIER HRRR RUN BROUGHT THE
PRECIP INTO THE SOUTHWEST CWA LATE THIS AFTERNOON...BUT IT WAS THE
OUTLIER AMONG THE SHORT TERM MODELS AND THE 13Z RUN KEEPS US DRY.
THE SOUTHWEST WILL SEE SOME CIRRUS FROM THE SYSTEM THOUGH. UPDATED
SKY TRENDS FOR THIS.
PREVIOUSLY FORECAST TEMPERATURES WERE GENERALLY ON TRACK BUT
SLIGHTLY REVISED AFTERNOON TRENDS BASED ON CHANGES TO SKY COVER AND
MID MORNING READINGS. LAKE BREEZE SCOURING AWAY CU NEAR THE LAKE AS
EXPECTED...AND WITH THE BREEZE TEMPERATURES SHOULD NOT CLIMB MUCH
MORE.
&&
.AVIATION/18Z TAFS/...
VFR CUMULUS WILL PERSIST THROUGH MUCH OF THE TODAY...DIMINISHING
LATE AFTERNOON AND EVENING. MID AND HIGH LEVEL CLOUDS WILL THEN
SLOWLY INCREASE FROM THE WEST OVERNIGHT. WITH HIGH PRESSURE SLIDING
TO THE EAST AND MORE CLOUDS EXPECTED...SHOULD SEE LESS AREAS OF
BR/FG THAN LAST NIGHT. BEST CHANCE FOR LOWER VSBYS WILL BE IN THE
EAST WHERE IT WILL LIKELY STAY MOSTLY CLEAR THROUGH MUCH OF THE
NIGHT.
PRECIP CHANCES FOR TOMORROW EXPECTED TO STAY SOUTHWEST OF
MADISON...WITH VFR CONDITIONS ACROSS THE AREA THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT SAT JUL 28 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
A NELY FETCH OFF LAKE MI AND WATER TO 850 MB TEMP DIFFERENCES OF
11-12C HAS RESULTED IN SCT-BKN STRATUS CLOUDS WITH EVEN A FEW
SHOWERS LAST NIGHT. SATELLITE TRENDS ARE SHOWING LESS CLOUDS AND
WILL COUNT ON NO MORE SHOWER ACTIVITY EARLY THIS AM. OTHERWISE
HIGH PRESSURE AND A LAKE BREEZE WILL BE THE MAIN WX FEATURES
TODAY. SCT-BKN CUMULUS WILL OCCUR ONCE AGAIN BUT WITHOUT THE
SHOWERS. 925-850 MB TEMPS SUGGEST SFC TEMPS IN THE LOWER 80S WITH
SLIGHTLY COOLER TEMPS NEAR THE LAKE.
FOR TNT...HIGH PRESSURE WILL GRADUALLY MOVE EWD BUT WINDS WILL
REMAIN VERY LIGHT WITH PATCHY FOG POSSIBLE LATE IN FAVORED AREAS.
EXPECT SOME INCREASE IN CLOUDS MAINLY IN THE WRN CWA LATE TNT AS A
WEAK VORTICITY MAXIMUM MOVES ACROSS IA AND THE ERN EXTENT OF A MID
LEVEL WARM ADVECTION ZONE AFFECTS SW WI. SLIGHT CHANCE FOR TSTORMS
FOR THE FAR SW CWA LATE.
SHORT TERM...SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE IS
MEDIUM.
NORTHWEST FLOW IN THE MID TO UPPER LEVELS LINGERS ACROSS THE
REGION DURING THIS TIME. NAM/ECMWF/CANADIAN AND GFS DIFFER WITH
TRENDS DURING THIS PERIOD. NAM/ECMWF/CANADIAN MODELS KEEP THE AREA
DRY SUNDAY...WITH LOW LEVEL JET NOSE REMAINING WEST OF THE AREA.
GFS BRINGS LIGHT QPF THROUGH THE AREA MAINLY SUNDAY AFTERNOON...AS
LOW LEVEL JET NOSE POINTS INTO THE AREA FROM THE SOUTHWEST.
ALL MODELS DO SHOW MODEST WARM AIR ADVECTION AND VARIOUS WEAK
VORTICITY MAXIMA SHIFTING THROUGH THE AREA. NAM FORECAST SOUNDINGS
QUITE DRY...WITH GFS SOUNDINGS SHOWING MORE LOW LEVEL
MOISTURE...THOUGH LIKELY A RESULT OF HIGH BIAS WITH DEWPOINTS AND
LOW LEVEL MOISTURE.
FOR NOW...WILL LEAVE SLIGHT CHANCE POPS GOING IN JUST THE FAR
SOUTHWEST COUNTIES. TEMPERATURES SHOULD RISE ABOVE NORMAL AWAY
FROM LAKE MICHIGAN...WITH NAM 925MB TEMPERATURES IN THE MID 20S
CELSIUS RANGE. ONSHORE WINDS WILL KEEP NEAR NORMAL TEMPERATURES
NEAR THE SHORE.
NOT SEEING MUCH IN THE WAY OF UPWARD VERTICAL MOTION POTENTIAL
SUNDAY NIGHT...WITH JUST SOME WEAK VORTICITY MAXIMA SHIFTING
THROUGH THE REGION. GFS ONLY MODEL WITH LIGHT QPF IN THE
AREA...AGAIN LIKELY OVERDONE DUE TO HIGH MOISTURE BIAS. WENT DRY
FOR SUNDAY NIGHT.
MODELS BRING MORE WARM AIR ADVECTION INTO THE AREA FOR
MONDAY...ALONG WITH DECENT VORTICITY MAXIMA PASSING THROUGH THE
AREA PER NAM/GFS. HIGHER DEWPOINTS IN THE LOWER TO MID 60S ARE
EXPECTED...WHICH SHOULD BRING IN MORE INSTABILITY. CAP IN 850MB
TO 700MB LAYER MAY LIMIT AREAL COVERAGE OF SHOWERS AND STORMS. FOR
NOW...WILL KEEP SLIGHT CHANCE POPS GOING FOR MONDAY...MAINLY IN
THE NORTHERN COUNTIES.
HIGHS COULD GET VERY WARM IF CLOUDS ARE NOT TOO WIDESPREAD. 925MB
TEMPERATURES FROM NAM SUGGEST HIGHS WELL INTO THE 90S AWAY FROM
THE LAKE. WILL GO SOMEWHAT LOWER WITH HIGHS GIVEN THE POSSIBILITY
FOR SOME MID LEVEL CLOUDS.
KEPT POPS GOING MONDAY NIGHT...AS MODELS BRING COLD FRONT
SOUTHEAST INTO OR THROUGH THE FORECAST AREA. MODEST SHORTWAVE
TROUGH DROPPING SOUTHEAST INTO THE AREA LATE MONDAY NIGHT WOULD
HELP WITH UPWARD VERTICAL MOTION. NAM FORECAST SOUNDINGS SUGGEST A
FAIRLY STRONG CAP MONDAY NIGHT...SO THAT WOULD BE A LIMITING
FACTOR.
LONG TERM...TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS
MEDIUM.
GFS/ECMWF SHOWING NORTHWEST FLOW IN THE MID TO UPPER LEVELS
LINGERING ACROSS THE REGION FOR MOST OF THIS PERIOD...EVENTUALLY
BECOMING MORE ZONAL BY LATE FRIDAY INTO NEXT WEEKEND.
COLD FRONT/MODEST SHORTWAVE PUSHES THROUGH THE AREA TUESDAY
MORNING...WITH HIGH PRESSURE PUSHING INTO THE AREA DURING THE
AFTERNOON. LOW POPS WILL BE KEPT FOR TUESDAY IN THE EASTERN
COUNTIES...WITH WARM TEMPERATURES LINGERING.
HIGH PRESSURE THEN SLIDES SOUTHEAST THROUGH THE AREA TUESDAY
NIGHT INTO WEDNESDAY...BRINGING QUIET WEATHER AND CONTINUED WARM
TEMPERATURES. SLIGHT CHANCES FOR PRECIPITATION WEDNESDAY IN THE
FAR NORTHWEST COUNTIES WITH COLD FRONTAL APPROACH.
ECMWF/GFS BRINGING ANOTHER COLD FRONT SOUTHEAST THROUGH THE AREA
WEDNESDAY NIGHT INTO THURSDAY. GFS HAS BETTER SHORTWAVE TROUGH
SLIDING THROUGH THE AREA...WITH THE ECMWF TO THE NORTHEAST OF THE
AREA. DECENT VORTICITY MAXIMUM THEN SLIDES EAST INTO THE AREA
FRIDAY FOR ANOTHER SHOT OF PRECIPITATION. KEPT GENERALLY LOW END
POPS AT TIMES DURING THIS PERIOD. TEMPERATURES SHOULD BE NEAR
SEASONAL NORMALS.
AVIATION/12Z TAFS/...
SCT LAKE EFFECT STRATUS CLOUDS WILL DISSIPATE BY MID MORNING WITH
A LAKE BREEZE TO THEN PREVAIL OVER FAR ERN WI. OTHERWISE HIGH
PRESSURE AND SCT-BKN CUMULUS CLOUDS AT 4-5 KFT WILL DEVELOP FROM
LATE MORNING THROUGH THE AFTERNOON AWAY FROM THE LAKE. CUMULUS TO
DISSIPATE QUICKLY EARLY THIS EVENING WITH SCT MID TO HIGH CLOUDS
INCREASING FROM WEST TO EAST ACROSS SRN WI THROUGHOUT THE NIGHT.
THE CLOUDS WILL BE THIN HOWEVER AND PATCHY FOG MAY DEVELOP IN LOW
LYING AREAS LATE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WIMBERLEY/DDV
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
SUNDAY THROUGH FRIDAY...WOOD