Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/27/12
AREA FORECAST DISCUSSION
NWS MIAMI FL
955 PM EDT THU JUL 26 2012
.UPDATE...A FEW THUNDERSTORMS MANAGED TO DEVELOP OVER THE INTERIOR
DURING THE LATE AFTERNOON AND EVENING HOURS. THE EVENING MIAMI
SOUNDING SHOWS A PWAT OF ONLY 1.40 INCHES WITH VERY DRY AIR ABOVE
6K FT...BUT THERE WAS ENOUGH SEA/LAKE BREEZE CONVERGENCE AND
STRONG HEATING TO GET A FEW TSTORMS GOING. THE TSTORMS HAVE SINCE
DISSIPATED WITH JUST A FEW SHOWERS CONTINUING OVER THE RURAL
INTERIOR. TRANQUIL WEATHER WILL PREVAIL OVERNIGHT. NO SIGNIFICANT
CHANGES ARE NEEDED TO THE FORECAST AT THIS TIME. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 731 PM EDT THU JUL 26 2012/
AVIATION...
THE WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT OVER ALL OF THE
TAF SITES BETWEEN 01Z AND 03Z. THE EAST COAST TAF SITES WINDS WILL
THEN REMAINED LIGHT AND VARIABLE THROUGH 16Z...BEFORE SWINGING TO
A SOUTHEAST DIRECTION AND INCREASING TO AROUND 10 KTS. FOR KAPF
TAF SITE...THE WINDS WILL ALSO REMAIN LIGHT AND VARIABLE FRIDAY
UNTIL 15Z BEFORE SWINGING TO A WESTERLY DIRECTION AT 5 TO 10
KNOTS. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS
AT ALL OF THE TAF SITES TONIGHT THROUGH FRIDAY AFTERNOON.
AVIATION..54/BNB
PREV DISCUSSION... /ISSUED 324 PM EDT THU JUL 26 2012/
UPDATE...A SHOWER HAS RECENTLY DEVELOPED NEAR THE IMMOKALEE
AREA...AND THE CU FIELD IS MORE ESTABLISHED OVER SOUTH FL THIS
AFTERNOON COMPARED TO YESTERDAY. HRRR SHOWS ISOLATED ACTIVITY
DEVELOPING, BECOMING FOCUSED ACROSS THE LAKE OKEECHOBEE REGION.
THERE STILL WILL BE A STRUGGLE TO GET MUCH CONVECTION GOING THIS
AFTERNOON, DUE TO A CAP, BUT STRONG HEATING COULD ALLOW FOR
ISOLATED TSTORMS TO DEVELOP. SO ADDED THIS POSSIBILITY TO THE
FORECAST. /GREGORIA
PREV DISCUSSION... /ISSUED 237 PM EDT THU JUL 26 2012/
DISCUSSION...
THE LATEST GUIDANCE CONTINUES TO INDICATE THE DRIER AND STABLE
AIR MASS CURRENTLY ACROSS THE REGION SHOULD PREVAIL INTO AND
LIKELY THROUGH THE WEEKEND. AN AREA OF HIGH SURFACE PRESSURE JUST
TO THE EAST OF THE BAHAMAS IS FORECAST TO PERSIST INTO AND LIKELY THROUGH
THE WEEKEND. THIS WILL MAINTAIN A WEAKER PRESSURE GRADIENT ACROSS
THE REGION WITH WINDS 10 KNOTS OR LESS ACROSS THE REGIONAL WATERS
WITH THE EAST AND WEST COAST SEA BREEZES EXPECTED EACH DAY FRIDAY
AND THROUGH THE WEEKEND. LOW LEVEL AVAILABLE MOISTURE IS FORECAST
TO BE LIMITED THROUGH THE WEEKEND WITH MINIMAL CHANCE OF
CONVECTION AND PRECIP ACROSS THE REGION AND NONE CURRENTLY IN THE
FORECAST FOR THE NEXT SEVERAL DAYS.
THE LATEST GUIDANCE FOR DUST CONCENTRATIONS INDICATE SAHARAN DUST
CONTINUING ACROSS THE AREA AT LEAST THROUGH FRIDAY WITH HAZY
SKIES EXPECTED AND WILL LIKELY EXTEND INTO THE WEEKEND AS WELL.
MARINE...
A LIGHT SOUTHERLY TO SOUTHEASTERLY FLOW NEAR 10 KNOTS OR LESS
WILL PREVAIL ACROSS REGIONAL WATERS TONIGHT AND IS EXPECTED TO
CONTINUE THROUGH THE WEEKEND WITH MAINLY TRANQUIL SEAS FORECAST
FOR THE LOCAL GULF AND ATLANTIC WATERS TONIGHT THROUGH THE
WEEKEND.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS.
&&
.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 TAMPA BAY RUSKIN FL
805 PM EDT THU JUL 26 2012
.UPDATE...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A LARGE AND DOMINANT UPPER
RIDGE EXTENDING FROM THE FL PENINSULA EASTWARD OVER THE ATLANTIC.
WEAK IMPULSE EMBEDDED WITHIN THIS RIDGE HAS BEEN SLOWLY MIGRATING
WESTWARD TO THE SOUTH OF THE FLORIDA PANHANDLE...AND HELPED TO
SUPPORT QUITE A BIT OF SHOWER/STORMS ACTIVITY THIS AFTERNOON TO THE
NORTH AND WEST OF THE SUWANNEE RIVER VALLEY. THE DRIER AIR ALOFT
THAT HAS BEEN ADVERTISED FOR SEVERAL DAYS HAS NOW ARRIVED AND IS
FIRMLY IN CONTROL OF THE AREA. THIS DRIER AIR IS PART OF A SAL
"SAHARAN AIR LAYER" WHICH HAS BEEN TRACKED ACROSS THE ATLANTIC FOR
DAYS. VISIBLE SATELLITE IMAGERY TODAY CLEARLY SHOWED THE HAZE/DUST
ASSOCIATED WITH THIS LAYER OVER THE CENTRAL/SOUTHERN PORTIONS OF THE
FORECAST AREA.
THE HOSTILE LOWER/MID LEVELS FOR DEEP CONVECTION KEPT JUST ABOUT ALL
OF THE FORECAST AREA DRY TODAY WITH THE EXCEPTION OF A FEW VERY
ISOLATED AND SHORT-LIVED CONVECTIVE CELLS. A FEW OF THESE WERE ABLE
TO BECOME ESTABLISHED TO THE WEST OF FORT MYERS THIS EVENING DUE TO
THE FAVORED CLASH OF THE EAST-COAST AND WEST-COAST SEABREEZE FRONTS.
ADDED A 20% POP IN FOR LEE AND CHARLOTTE COUNTIES TILL 10PM EDT TO
ACCOUNT FOR THE WESTWARD DRIFT OF THESE CELLS...HOWEVER WITH THE
HOSTILITY OF THE COLUMN...WOULD EXPECT THESE STORMS TO NOT LINGER
MUCH LONGER...ESPECIALLY AS THE DIURNAL CYCLE BRINGS THE LOW LEVEL
CONVERGENCE MAX TO A QUICK END.
THE REMAINDER OF THE OVERNIGHT LOOKS DRY AND QUIET FOR THE AREA.
VISIBLE SATELLITE DOES SHOW A WEAK CONVERGENCE BAND EXTENDING OUT
INTO THE GULF FROM THE MOUTH OF TAMPA BAY. NOT IMPOSSIBLE THAT AN
ISOLATED SHALLOW SHOWER OR 2 COULD POP UP ON THIS BAND DURING THE
LATE NIGHT HOURS AND WORK BACK TOWARD THE MANATEE/PINELLAS COASTS.
HOWEVER...ANY ACTIVITY SHOULD BE BRIEF AND FEEL CHANCES ARE LOW
ENOUGH TO LEAVE OUT OF THE FORECAST.
ONLY OTHER MINOR TWEAK TO THE GRIDS WAS TO REMOVE MENTION OF
ISOLATED SHOWERS DURING THE MORNING HOURS OF FRIDAY. A SIMILAR
HOSTILE COLUMN WILL GENERALLY KEEP JUST ABOUT ALL OF THE REGION DRY
ONCE AGAIN...AND THE ISOLATED CELLS WE DO SEE SHOULD HOLD OFF UNTIL
THE SEA-BREEZE IS WELL ESTABLISHED DURING THE AFTERNOON HOURS. HAVE
A GREAT NIGHT!
&&
.PREVIOUS DISCUSSION (FRIDAY-SATURDAY)...
THE FORECAST WILL BE BELOW NORMAL FOR RAINFALL BUT WILL KEEP MAINLY
AFTERNOON SHOWERS AND THUNDERSTORMS IN THE ISOLATED CATEGORY...ABOVE
THE LATEST MOS GUIDANCE. TEMPERATURES WILL RUN AT OR ABOVE NORMAL.
AFTERNOON HEAT INDEX VALUES REACH INTO THE 100-105 RANGE...ESPECIALLY
INLAND BUT STAY UNDER THE 108 HEAT ADVISORY THRESHOLD. THE SURFACE
RIDGE AXIS TO THE SOUTH WILL KEEP WINDS SW AND WEST AND GENERALLY
LIGHT.
.LONG TERM (SATURDAY NIGHT - THURSDAY)...
GLOBAL MODELS REMAIN IN GOOD AGREEMENT SHOWING DEEP LAYER RIDGING
HOLDING IN PLACE THROUGH EARLY NEXT WEEK...BEFORE BREAKING DOWN
BY THE MIDDLE AND LATTER PART OF NEXT WEEK AS UPPER LEVEL
TROUGHING BECOMES BETTER ESTABLISHED OVER THE EASTERN THIRD OF THE
COUNTRY. PRECIPITABLE WATER VALUES WILL REMAIN WELL BELOW NORMAL
THROUGH EARLY NEXT WEEK...BEFORE TRENDING CLOSER TO CLIMATOLOGY BY
THE MIDDLE AND LATTER PART OF NEXT WEEK.
AS FOR FORECAST DETAILS...WILL KEEP RAIN CHANCES LOW GENERALLY
AROUND 20% THROUGH TUESDAY...WITH PROBABILITIES INCREASING INTO
THE 30% TO 40% RANGE BY NEXT WEDNESDAY AND THURSDAY.
TEMPERATURES WILL CONTINUE TO RUN NEAR TO SLIGHTLY ABOVE NORMAL
THROUGH THE LONG TERM PERIODS.
&&
.AVIATION...
MAINLY VFR NEXT 24 HOURS. LINE OF SHOWERS AND STORMS MAY IMPACT
FMY...RSW AND PGD THROUGH 03Z OR SO...THEN SOME CLOUDS WITH BASES
AROUND 2000 FEET WILL MOVE IN OFF THE GULF NEAR PIE AND TPA
OVERNIGHT. AFTERNOON STORMS ON FRIDAY SHOULD BE WELL INLAND AND VERY
LOW COVERAGE...SO NO MENTION IN TAFS AT THIS TIME.
&&
.MARINE...
ATLANTIC HIGH PRESSURE WILL RIDGE WESTWARD...WITH AN AXIS THAT
MEANDERS A BIT ACROSS SOUTHERN FL...INTO THE GULF THROUGH EARLY
NEXT WEEK. THE LOCATION OF THIS RIDGE WILL MAINTAIN MOSTLY LIGHT
SOUTHWESTERLY AND WESTERLY WINDS ON THE COASTAL WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 93 77 93 / 10 20 10 20
FMY 76 95 76 94 / 20 20 10 20
GIF 75 95 75 95 / 10 20 10 20
SRQ 77 93 77 93 / 10 10 10 10
BKV 71 94 72 94 / 10 20 10 20
SPG 79 93 79 93 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
PREVIOUS DISCUSSION...RUDE/JELSEMA
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
731 PM EDT THU JUL 26 2012
.AVIATION...
THE WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT OVER ALL OF THE
TAF SITES BETWEEN 01Z AND 03Z. THE EAST COAST TAF SITES WINDS WILL
THEN REMAINED LIGHT AND VARIABLE THROUGH 16Z...BEFORE SWINGING TO
A SOUTHEAST DIRECTION AND INCREASING TO AROUND 10 KTS. FOR KAPF
TAF SITE...THE WINDS WILL ALSO REMAIN LIGHT AND VARIABLE FRIDAY
UNTIL 15Z BEFORE SWINGING TO A WESTERLY DIRECTION AT 5 TO 10
KNOTS. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS
AT ALL OF THE TAF SITES TONIGHT THROUGH FRIDAY AFTERNOON.
&&
.AVIATION..54/BNB
.PREV DISCUSSION... /ISSUED 324 PM EDT THU JUL 26 2012/
UPDATE...A SHOWER HAS RECENTLY DEVELOPED NEAR THE IMMOKALEE
AREA...AND THE CU FIELD IS MORE ESTABLISHED OVER SOUTH FL THIS
AFTERNOON COMPARED TO YESTERDAY. HRRR SHOWS ISOLATED ACTIVITY
DEVELOPING, BECOMING FOCUSED ACROSS THE LAKE OKEECHOBEE REGION.
THERE STILL WILL BE A STRUGGLE TO GET MUCH CONVECTION GOING THIS
AFTERNOON, DUE TO A CAP, BUT STRONG HEATING COULD ALLOW FOR
ISOLATED TSTORMS TO DEVELOP. SO ADDED THIS POSSIBILITY TO THE
FORECAST. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 237 PM EDT THU JUL 26 2012/
DISCUSSION...
THE LATEST GUIDANCE CONTINUES TO INDICATE THE DRIER AND STABLE
AIR MASS CURRENTLY ACROSS THE REGION SHOULD PREVAIL INTO AND
LIKELY THROUGH THE WEEKEND. AN AREA OF HIGH SURFACE PRESSURE JUST
TO THE EAST OF THE BAHAMAS IS FORECAST TO PERSIST INTO AND LIKELY THROUGH
THE WEEKEND. THIS WILL MAINTAIN A WEAKER PRESSURE GRADIENT ACROSS
THE REGION WITH WINDS 10 KNOTS OR LESS ACROSS THE REGIONAL WATERS
WITH THE EAST AND WEST COAST SEA BREEZES EXPECTED EACH DAY FRIDAY
AND THROUGH THE WEEKEND. LOW LEVEL AVAILABLE MOISTURE IS FORECAST
TO BE LIMITED THROUGH THE WEEKEND WITH MINIMAL CHANCE OF
CONVECTION AND PRECIP ACROSS THE REGION AND NONE CURRENTLY IN THE
FORECAST FOR THE NEXT SEVERAL DAYS.
THE LATEST GUIDANCE FOR DUST CONCENTRATIONS INDICATE SAHARAN DUST
CONTINUING ACROSS THE AREA AT LEAST THROUGH FRIDAY WITH HAZY
SKIES EXPECTED AND WILL LIKELY EXTEND INTO THE WEEKEND AS WELL.
MARINE...
A LIGHT SOUTHERLY TO SOUTHEASTERLY FLOW NEAR 10 KNOTS OR LESS
WILL PREVAIL ACROSS REGIONAL WATERS TONIGHT AND IS EXPECTED TO
CONTINUE THROUGH THE WEEKEND WITH MAINLY TRANQUIL SEAS FORECAST
FOR THE LOCAL GULF AND ATLANTIC WATERS TONIGHT THROUGH THE
WEEKEND.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS.
&&
.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.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...47/RGH
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
337 PM EDT WED JUL 25 2012
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
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/...
HAVE MADE NO CHANGES TO THE LONG TERM. MODELS CONSISTEND 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 07-25
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAHN 101 1981 74 2000 75 1983 61 1947
1952 1911
1912
KATL 102 1995 74 1882 78 2010 60 1882
KCSG 103 1952 82 1998 80 2010 66 1948
1983
KMCN 103 1952 79 1938 79 2010 64 2009
1909
1902
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...
18Z UPDATE...
VFR CONDITIONS EXPECTED THROUGH FORECAST PERIOD WITH SOME REDUCED
VSBYS POTENTIALLY OCCURRING WITH ANY TSRA THIS AFTERNOON. BEST
CHANCE FOR CONVECTION WILL BE NEAR KMCN AND KCSG AROUND 21Z THEREFORE
INCLUDED TEMPO GROUP AT THESE SITES. CHANCE IS TOO LOW AT OTHER
SITES TO MENTION BUT THE POTENTIAL FOR ISOLATED TSRA IS STILL
THERE. MOSTLY NW WINDS OF 10KTS OR LESS WITH GUSTS NEAR 18KTS CAN
BE EXPECTED TO CONTINUE THIS AFTERNOON FOR KATL AND A FEW OTHER
SITES. WINDS SHOULD BACK TO MORE WESTERLY OVERNIGHT AT 5-3KTS. FOR
CIGS... EXPECT SCT TO FEW AT NEAR 4 KFT DURING DAYTIME HOURS AND
INCREASE TO BKN NEAR ANY STORM DEVELOPMENT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF CONVECTION IN SOUTH.
HIGH CONFIDENCE ALL ELSE.
03
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 73 98 74 98 / 20 20 20 30
ATLANTA 76 96 75 94 / 10 30 20 40
BLAIRSVILLE 68 91 69 90 / 10 20 20 50
CARTERSVILLE 72 96 73 94 / 10 20 20 50
COLUMBUS 76 95 75 93 / 20 40 30 40
GAINESVILLE 74 93 74 94 / 20 20 20 40
MACON 75 96 74 97 / 20 40 30 30
ROME 73 97 73 94 / 10 20 20 50
PEACHTREE CITY 73 95 73 94 / 10 30 20 40
VIDALIA 78 100 77 97 / 20 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BALDWIN...BIBB...BLECKLEY...CHATTAHOOCHEE...CRAWFORD...
CRISP...DODGE...DOOLY...EMANUEL...GLASCOCK...GREENE...HANCOCK...
HARRIS...HOUSTON...JEFFERSON...JOHNSON...JONES...LAURENS...
MACON...MARION...MONROE...MONTGOMERY...MUSCOGEE...PEACH...
PULASKI...PUTNAM...SCHLEY...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TREUTLEN...TWIGGS...
UPSON...WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX...
WILKES...WILKINSON.
&&
$$
SHORT TERM...BAKER
LONG TERM....41
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
100 PM CDT WED JUL 25 2012
.DISCUSSION...
ISSUED 1041 AM CDT WED JUL 25 2012
THE WARM FRONT IS CONTINUING TO LIFT NORTHEAST ACROSS CENTRAL IL
WITH DRIER AIR BEHIND IT. DEWPOINTS ARE HOLDING IN THE LOWER 70S
ALONG AND NORTH OF THE FRONT. OUR HIGH TEMPS WILL BE CLOSELY TIED
TO HOW MUCH DRY AIR MIXES TO THE SURFACE. IF OUR DEWPOINTS DO NOT
MIX DOWN INTO THE 60 TO 65 DEGREE RANGE, OUR HIGH TEMPS WILL
MOST LIKELY NOT REACH 103-106 RANGE IN THOSE AREAS. WE TRIMMED
HIGHS SLIGHTLY DUE TO SOME DELAY IN MIXING SO FAR, AND THE AMOUNT
OF MOISTURE/DEWPOINT LEVELS IN OUR 12Z SOUNDING. STILL...WE WILL
REACH VERY CLOSE TO RECORD HIGHS SOUTHWEST OF THE FRONT.
CLOUD COVER LOOKS TO BE MINIMAL FOR AT LEAST THE WESTERN HALF OF
THE AREA. THE CU RULE IS SHOWING CU FORMATION MORE FAVORABLE EAST
OF I-57. HOWEVER...EVEN THOSE CLOUDS WILL BE A THIN LAYER AND NOT
LAST VERY LONG INTO THE AFTERNOON.
NO OTHER CHANGES WERE NEEDED TO THE GOING FORECAST. UPDATED INFO
WILL BE AVAILABLE SHORTLY.
&&
.AVIATION...
ISSUED 1259 PM CDT WED JUL 25 2012
FAIRLY QUIET WEATHER IS IN STORE FOR TODAY... WITH VFR CONDITIONS
EXPECTED THROUGH THIS TAF CYCLE. NOT MUCH IN THE WAY OF CLOUD COVER
THIS AFTERNOON...WITH ONLY A FEW DIURNAL CU. WINDS WILL GENERALLY BE
OUT OF THE SOUTHWEST WITH SPEEDS AROUND 10 KTS. SOME STRONGER WINDS
ALOFT WILL BE MIXED DOWN TO THE SURFACE THIS AFTERNOON...SO HAVE
INCLUDED GUSTS UP TO 20 KTS. AFTER SUNSET...DIURNAL CU AND GUSTS
WILL DIMINISH. LLJ WILL CRANK UP OVERNIGHT SO HAVE ADDED A LINE FOR
LLWS AFTER 06Z...AS LATEST MODEL SOUNDINGS SHOW WINDS AROUND 40 KTS
AT 2KFT. A COLD FRONT WILL APPROACH THE AREA TOMORROW MORNING SO
HAVE KEPT VCSH IN THE TAF FOR NOW AND WILL REFINE TIMING/COVERAGE
WITH LATER ISSUANCES.
ECT/SHIMON
&&
.FIRE WEATHER...
ISSUED 300 AM CDT WED JUL 25 2012
HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP
MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS
A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL
TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY
VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS
THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25
MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS
AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH...
JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT
TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY
POTENTIAL NEED FOR A RED FLAG WARNING.
GEELHART
&&
.CLIMATE...
ISSUED 300 AM CDT WED JUL 25 2012
RECORD HIGH TEMPERATURES FOR TODAY...
BLOOMINGTON...... 106/1934
CHAMPAIGN........ 104/1934
CHARLESTON....... 105/1934
DECATUR.......... 104/1934
JACKSONVILLE..... 108/1934
LINCOLN.......... 105/1934
OLNEY............ 103/1940
PALESTINE........ 103/1901
PEORIA........... 104/1930
SPRINGFIELD...... 103/1936
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 AM CDT WED JUL 25 2012
LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE
WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS
MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED
THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA
THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO
OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER
70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO
THE BOUNDARY.
MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY
AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE
CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE
CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID-
MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE
ACTIVITY IN THE ZONES.
OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT
HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING
EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE
AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN
FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE
THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND
20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT
TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF
103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH
THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES
ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE
HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70
THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO
POTENTIAL FOR CLOUDS AND STORMS.
UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN
TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE
OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR
EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST
OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN
INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE
FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE
NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING
INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING
ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL
SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING
THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT.
LONG TERM...FRIDAY THROUGH TUESDAY...
UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS
WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES.
THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE
WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN...
POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL
INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE
FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A
BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN
CHANCES AT THIS TIME.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1042 AM CDT WED JUL 25 2012
.DISCUSSION...
ISSUED 1041 AM CDT WED JUL 25 2012
THE WARM FRONT IS CONTINUING TO LIFT NORTHEAST ACROSS CENTRAL IL
WITH DRIER AIR BEHIND IT. DEWPOINTS ARE HOLDING IN THE LOWER 70S
ALONG AND NORTH OF THE FRONT. OUR HIGH TEMPS WILL BE CLOSELY TIED
TO HOW MUCH DRY AIR MIXES TO THE SURFACE. IF OUR DEWPOINTS DO NOT
MIX DOWN INTO THE 60 TO 65 DEGREE RANGE, OUR HIGH TEMPS WILL
MOST LIKELY NOT REACH 103-106 RANGE IN THOSE AREAS. WE TRIMMED
HIGHS SLIGHTLY DUE TO SOME DELAY IN MIXING SO FAR, AND THE AMOUNT
OF MOISTURE/DEWPOINT LEVELS IN OUR 12Z SOUNDING. STILL...WE WILL
REACH VERY CLOSE TO RECORD HIGHS SOUTHWEST OF THE FRONT.
CLOUD COVER LOOKS TO BE MINIMAL FOR AT LEAST THE WESTERN HALF OF
THE AREA. THE CU RULE IS SHOWING CU FORMATION MORE FAVORABLE EAST
OF I-57. HOWEVER...EVEN THOSE CLOUDS WILL BE A THIN LAYER AND NOT
LAST VERY LONG INTO THE AFTERNOON.
NO OTHER CHANGES WERE NEEDED TO THE GOING FORECAST. UPDATED INFO
WILL BE AVAILABLE SHORTLY.
SHIMON/ECT
&&
.AVIATION...
ISSUED 633 AM CDT WED JUL 25 2012
VFR THROUGHOUT THE FORECAST FOR NOW. WARM FRONT LIFTING BACK
THROUGH THE AREA THIS MORNING...WITH WINDS RETURNING TO SWRLY AND
GUSTING 20-25 KTS THIS AFTERNOON AS THE APPROACHING STORM SYSTEM
BRINGS A PRESSURE GRADIENT BACK TO THE REGION. SOME SCT AC
POSSIBLE THIS AFTERNOON...SHORT TIME OF CLEARING AGAIN THIS
EVENING. AS THE SYSTEM PASSES TO THE NORTH...ANOTHER FRONT DROPS
BACK INTO THE AREA. POPS START TO SPREAD TONIGHT...MAINLY AFTER
MIDNIGHT. BROUGHT VCSH FOR PIA AND BMI AT 09Z...BUT MOST OF PRECIP
WILL AFFECT TOMORROW DURING THE LATE AFTERNOON. NOT GETTING MORE
EXPANSIVE THAN THAT RIGHT NOW.
HJS
&&
.FIRE WEATHER...
ISSUED 300 AM CDT WED JUL 25 2012
HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP
MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS
A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL
TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY
VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS
THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25
MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS
AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH...
JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT
TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY
POTENTIAL NEED FOR A RED FLAG WARNING.
GEELHART
&&
.CLIMATE...
ISSUED 300 AM CDT WED JUL 25 2012
RECORD HIGH TEMPERATURES FOR TODAY...
BLOOMINGTON...... 106/1934
CHAMPAIGN........ 104/1934
CHARLESTON....... 105/1934
DECATUR.......... 104/1934
JACKSONVILLE..... 108/1934
LINCOLN.......... 105/1934
OLNEY............ 103/1940
PALESTINE........ 103/1901
PEORIA........... 104/1930
SPRINGFIELD...... 103/1936
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 AM CDT WED JUL 25 2012
LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE
WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS
MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED
THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA
THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO
OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER
70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO
THE BOUNDARY.
MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY
AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE
CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE
CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID-
MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE
ACTIVITY IN THE ZONES.
OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT
HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING
EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE
AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN
FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE
THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND
20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT
TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF
103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH
THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES
ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE
HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70
THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO
POTENTIAL FOR CLOUDS AND STORMS.
UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN
TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE
OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR
EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST
OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN
INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE
FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE
NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING
INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING
ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL
SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING
THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT.
LONG TERM...FRIDAY THROUGH TUESDAY...
UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS
WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES.
THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE
WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN...
POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL
INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE
FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A
BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN
CHANCES AT THIS TIME.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ036-040>042-
047>057-061>063-066>068-071>073.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-037-038-
043>046.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
638 AM CDT WED JUL 25 2012
.DISCUSSION...
ISSUED 300 AM CDT WED JUL 25 2012
LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE
WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS
MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED
THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA
THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO
OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER
70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO
THE BOUNDARY.
MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY
AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE
CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE
CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID-
MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE
ACTIVITY IN THE ZONES.
OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT
HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING
EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE
AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN
FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE
THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND
20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT
TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF
103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH
THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES
ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE
HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70
THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO
POTENTIAL FOR CLOUDS AND STORMS.
UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN
TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE
OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR
EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST
OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN
INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE
FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE
NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING
INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING
ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL
SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING
THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT.
LONG TERM...FRIDAY THROUGH TUESDAY...
UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS
WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES.
THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE
WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN...
POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL
INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE
FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A
BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN
CHANCES AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 633 AM CDT WED JUL 25 2012
VFR THROUGHOUT THE FORECAST FOR NOW. WARM FRONT LIFTING BACK
THROUGH THE AREA THIS MORNING...WITH WINDS RETURNING TO SWRLY AND
GUSTING 20-25 KTS THIS AFTERNOON AS THE APPROACHING STORM SYSTEM
BRINGS A PRESSURE GRADIENT BACK TO THE REGION. SOME SCT AC
POSSIBLE THIS AFTERNOON...SHORT TIME OF CLEARING AGAIN THIS
EVENING. AS THE SYSTEM PASSES TO THE NORTH...ANOTHER FRONT DROPS
BACK INTO THE AREA. POPS START TO SPREAD TONIGHT...MAINLY AFTER
MIDNIGHT. BROUGHT VCSH FOR PIA AND BMI AT 09Z...BUT MOST OF PRECIP
WILL AFFECT TOMORROW DURING THE LATE AFTERNOON. NOT GETTING MORE
EXPANSIVE THAN THAT RIGHT NOW.
HJS
&&
.FIRE WEATHER...
ISSUED 300 AM CDT WED JUL 25 2012
HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP
MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS
A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL
TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY
VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS
THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25
MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS
AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH...
JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT
TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY
POTENTIAL NEED FOR A RED FLAG WARNING.
GEELHART
&&
.CLIMATE...
ISSUED 300 AM CDT WED JUL 25 2012
RECORD HIGH TEMPERATURES FOR TODAY...
BLOOMINGTON...... 106/1934
CHAMPAIGN........ 104/1934
CHARLESTON....... 105/1934
DECATUR.......... 104/1934
JACKSONVILLE..... 108/1934
LINCOLN.......... 105/1934
OLNEY............ 103/1940
PALESTINE........ 103/1901
PEORIA........... 104/1930
SPRINGFIELD...... 103/1936
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ036-040>042-
047>057-061>063-066>068-071>073.
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
ILZ027>031-037-038-043>046.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
302 AM CDT WED JUL 25 2012
.DISCUSSION...
ISSUED 300 AM CDT WED JUL 25 2012
LATEST SURFACE MAP SHOWING FRONTAL BOUNDARY CURVING AROUND THE
WEST AND SOUTHERN FRINGES OF THE FORECAST AREA EARLY THIS
MORNING...PUSHING NORTHWARD. HAVE BEEN SEEING SOME SCATTERED
THUNDERSTORMS DEVELOPING OVER MAINLY THE EASTERN HALF OF THE CWA
THE LAST FEW HOURS...BUT A LARGE AREA OF CLEAR SKIES WAS JUST TO
OUR WEST. TEMPERATURES NORTH OF I-74 HAVE DIPPED INTO THE LOWER
70S AS OF 2 AM...BUT STILL SEEING QUITE A FEW LOWER 80S CLOSER TO
THE BOUNDARY.
MAIN CONCERNS ARE IN THE SHORT TERM...NAMELY THE RECORD HEAT TODAY
AND ANY POTENTIAL NEED FOR ADJUSTMENTS TO HEADLINES. ALSO HAVE
CONCERNS WITH CONVECTIVE DEVELOPMENT OVER THE NEXT 24 TO 36 HOURS.
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
LATEST VERSIONS OF THE NAM-12 AND HRRR HAVE A FAIR HANDLE ON THE
CURRENT CONVECTION...AND HAVE THE RAIN OUT OF THE AREA BY MID-
MORNING. WILL MAKE A LAST-MINUTE CALL ON HOW TO HANDLE THE
ACTIVITY IN THE ZONES.
OTHERWISE...THE MAIN STORY WILL BE THE BRUTAL HEAT. TIME-HEIGHT
HUMIDITY CROSS SECTIONS SHOWING ANY CLOUD COVER RAPIDLY MOVING
EAST OF THE AREA LATE THIS MORNING AS THE FRONT LIFTS NORTH OF THE
AREA. DEEP MIXING FROM AROUND 750 MB SHOULD BRING DRIER AIR DOWN
FROM ABOVE..AND HELP DROP DEW POINTS INTO THE 60-65 DEGREE RANGE
THIS AFTERNOON. WINDS ALSO EXPECTED TO PICK UP AND GUST TO AROUND
20-25 MPH. TEMPERATURES AGAIN EXPECTED TO SOAR INTO TRIPLE DIGIT
TERRITORY...AND HAVE NOT MADE ANY CHANGES TO EARLIER HIGHS OF
103-107. MUCH OF THE CWA LIKELY TO SEE RECORD HIGHS TODAY. WITH
THE DRIER AIR...HEAT INDEX VALUES SHOULD ONLY BE A FEW DEGREES
ABOVE THE OBSERVED TEMPERATURES. THERE ARE SOME CONCERNS THAT THE
HEAT ADVISORY WILL NEED TO BE EXTENDED IN AREAS SOUTH OF I-70
THROUGH THURSDAY. HOWEVER...THE NEED IS NOT CLEAR-CUT...DUE TO
POTENTIAL FOR CLOUDS AND STORMS.
UPPER RIDGE OVER THE MISSISSIPPI VALLEY WILL CONTINUE TO FLATTEN
TODAY...AS A COLD FRONT DROPS SOUTHEAST TOWARD THE AREA. PASSAGE
OF THE FRONT THROUGH OUR CWA WILL LIKELY TAKE UNTIL MIDDAY OR
EARLY AFTERNOON ON THURSDAY. WILL SEE SCATTERED THUNDERSTORMS WEST
OF I-55 DEVELOP LATER TONIGHT AS THE FRONT APPROACHES...THEN
INCREASE OVER THE CWA ON THURSDAY WITH THE HEATING AHEAD OF THE
FRONT. MAIN SEVERE WEATHER THREAT TODAY WILL REMAIN TO THE
NORTH...BUT SOME SEVERE STORMS ARE POSSIBLE LATE THURSDAY MORNING
INTO THE AFTERNOON. WILL SEE SCATTERED STORMS LINGER INTO EVENING
ACROSS THE EASTERN CWA. THE NAM MODEL DOES DEVELOP SOME ADDITIONAL
SHOWERS LATE THURSDAY NIGHT WITH A SECONDARY BOUNDARY COMING
THROUGH THE AREA...BUT THIS DOES NOT SEEM LIKELY AT THE MOMENT.
LONG TERM...FRIDAY THROUGH TUESDAY...
UPPER RIDGE TO RE-ESTABLISH ITSELF OVER THE ROCKIES THIS
WEEKEND...WITH A BROAD TROUGH PUSHING THROUGH THE GREAT LAKES.
THIS WILL ALLOW FOR SOME MORE REASONABLE TEMPERATURES FOR THE
WEEKEND. AS THE RIDGE BEGINS TO SHIFT BACK EASTWARD AGAIN...
POTENTIAL FOR MCS ACTIVITY OVER THE TOP OF THE RIDGE WILL
INCREASE OVER OUR AREA. MOST LIKELY TIME FRAMES FOR THIS WILL BE
FROM SUNDAY NIGHT THROUGH TUESDAY...BUT EXACT LOCATIONS STILL A
BIT OF A QUESTION. AS SUCH...WILL NOT GO OVERBOARD ON THE RAIN
CHANCES AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 1152 PM CDT TUE JUL 24 2012
VFR CONDITIONS WILL CONTINUE NEXT 24HRS AT ALL TAF SITES.
SCATTERED AC WILL LIKELY CONTINUE AT ALL SITES OVERNIGHT AND INTO
THE MORNING HOURS. AC APPEARS TO BE IN RESPONSE TO THE SFC FRONT
LIFTING BACK NORTH OVERNIGHT. BASED ON SATELLITE LOOPS FROM THIS
AFTERNOON BACK WEST...BELIEVE SCATTER AC WILL CONTINUE FOR MOST OF
THE DAY AND THEN DISSIPATE DURING THE EVENING HOURS
TOMORROW...RESULTING IN CLEAR SKIES TOMORROW EVENING. GOING TO
HAVE AC AT 8-9KFT. WINDS WILL BE EASTERLY OVERNIGHT AND THEN
BECOME SOUTHEAST IN THE MORNING PRIOR TO THE FRONT MOVING NORTH OF
THE SITES...THEN SOUTHWEST DURING THE LATE MORNING TO AFTERNOON
AFTER THE FRONT MOVES NORTH. WIND SPEEDS WILL INCREASE TOMORROW
BEHIND THE FRONT AS GRADIENT TIGHTENS AHEAD OF THE COLD
FRONT...THEN DECREASE AROUND SUNSET.
AUTEN
&&
.FIRE WEATHER...
ISSUED 300 AM CDT WED JUL 25 2012
HAVE CONCERNS WITH RED FLAG POTENTIAL FOR THIS AFTERNOON. DEEP
MIXING SHOULD ALLOW DEW POINTS TO FALL INTO THE LOWER 60S ACROSS
A GOOD PORTION OF THE CWA THIS AFTERNOON. WITH THE BRUTAL
TEMPERATURES EXPECTED...THIS LEVEL OF MIXING WOULD DROP HUMIDITY
VALUES INTO THE 20-25 PERCENT RANGE THIS AFTERNOON. MAIN ISSUE IS
THAT WINDS WILL BE A BIT BORDERLINE. SURFACE WIND GUSTS AROUND 25
MPH WILL BE POSSIBLE ACROSS PRIMARILY AREAS WEST OF I-55 BY THIS
AFTERNOON...BUT 20-FOOT SUSTAINED WINDS WILL BE CLOSER TO 15 MPH...
JUST SHY OF CRITERIA. WILL CONTINUE THE SPECIAL WEATHER STATEMENT
TO HIGHLIGHT THE FIRE DANGER...AND CONTINUE TO MONITOR FOR ANY
POTENTIAL NEED FOR A RED FLAG WARNING.
GEELHART
&&
.CLIMATE...
ISSUED 300 AM CDT WED JUL 25 2012
RECORD HIGH TEMPERATURES FOR TODAY...
BLOOMINGTON...... 106/1934
CHAMPAIGN........ 104/1934
CHARLESTON....... 105/1934
DECATUR.......... 104/1934
JACKSONVILLE..... 108/1934
LINCOLN.......... 105/1934
OLNEY............ 103/1940
PALESTINE........ 103/1901
PEORIA........... 104/1930
SPRINGFIELD...... 103/1936
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ036-040>042-
047>057-061>063-066>068-071>073.
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
ILZ027>031-037-038-043>046.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
659 AM EDT WED JUL 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 300 AM EDT WED JUL 25 2012
AN UPPER RIDGE ACROSS THE MISSISSIPPI VALLEY WILL BUILD ACROSS THE
OHIO VALLEY AND SOUTHERN STATES LATE TODAY. THIS WILL PUSH A
QUASI-STATIONARY FRONT...CURRENTLY NEAR THE OHIO RIVER...NORTHEAST
INTO MICHIGAN. THIS WILL RESULT IN A TEMPORARY END TO THUNDERSTORM
CHANCES AND MORE HOT AND HUMID CONDITIONS WITH AFTERNOON HIGHS
AROUND 100 OR MORE AND HEAT INDICES TO NEAR 110. THEN...AN UPPER
LOW...ACROSS THE CANADIAN PRAIRIES AT THIS TIME...WILL DROP
SOUTHEAST BEFORE OPENING UP NEAR THE WESTERN SHORES OF LAKE
SUPERIOR. THIS WILL CAUSE THE UPPER FLOW TO BUCKLE AND FORCE A COLD
FRONT THROUGH CENTRAL INDIANA LATE THURSDAY INTO EARLY FRIDAY. THE
RESULT WILL BE THUNDERSTORM CHANCES THURSDAY THROUGH FRIDAY ALONG
WITH MORE SEASONABLE TEMPERATURES IN THE 80S IN THE WAKE OF THE
FRONT FOR THE WEEKEND. FINALLY...THE COLD FRONT WILL STALL ACROSS
THE SOUTH AND GRADUALLY LIFT NORTHEASTWARD AND COMBINE WITH
DISTURBANCES IN THE FAST UPPER FLOW TO BRING MORE THUNDERSTORM
CHANCES TO CENTRAL INDIANA SUNDAY NIGHT AND THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 300 AM EDT WED JUL 25 2012
MAIN CONCERN TODAY WILL BE THE HEAT...ALTHOUGH THUNDERSTORM CHANCES
WILL ALSO BE UNDER THE MAGNIFYING GLASS.
RADAR LOOP EARLY OVERNIGHT CONTINUED TO SHOW SCATTERED THUNDERSTORMS
ACROSS SOUTHWESTERN PARTS OF THE FORECAST NEAR A QUASI-STATIONARY
FRONT FROM AROUND SULLIVAN TO COLUMBUS AND JUST AHEAD OF AN UPPER
DISTURBANCE ACROSS SOUTHERN ILLINOIS. THE LATTER FEATURE WAS JUST
AHEAD OF AN UPPER RIDGE AXIS FROM CENTRAL MINNESOTA TO EASTERN TEXAS
AND WESTERN LOUISIANA. THIS RIDGE WILL PROPAGATE EAST TO THE
MISSISSIPPI VALLY BY LATE MORNING AND THE OHIO VALLEY TO THE GULF
LATE IN THE DAY. THIS WILL RESULT IN THE SOUTH CENTRAL IINDIANA
FRONT LIFTING NORTHEAST INTO SOUTHERN LOWER MICHIGAN LATE IN THE
DAY. AS THE FRONT LIFTS NORTHEAST...PLENTY OF INSTABILITY IS
EXPECTED TODAY WITH MIXED LAYER CAPES 2500 J/KG OR MORE POOLED ALONG
THE FRONT. WITH THE RIDGE MOVING IN AND THE FRONT LIFTING THROUGH
THOUGH...WILL CONFINE POPS TO THE MORNING AND EARLY AFTERNOON HOURS
WITH BEST CHANCE NORTHEAST CLOSER TO THE EXPECTED MID DAY FRONTAL
POSITION. SHOULD SEE A GOOD DEGREE OF SUNSHINE IN THE WARM
SECTOR...AND MODEL 850 MILLIBAR TEMPERATURES FROM 24 TO 26 DEGREES
AGAIN SUGGEST TEMPERATURES AROUND 100 DEGREES AND A FEW DEGREES
WARMER SOUTHWEST. DEW POINTS MOSTLY IN THE UPPER 60S AND LOWER 70S
AS THEY WERE YESTERDAY AFTERNOON IN THE WARM SECTOR WOULD PRODUCE
HEAT INDICES NEAR 110 DEGREES AND CERTAINLY JUSTIFIES CONTINUING THE
HEAT ADVISORY FOR THE SOUTHWEST AND FOR ALL COUNTIES AFTER 15Z AND
THROUGH 00Z THIS EVENING.
ONCE AGAIN...THE NAM MOS LOOKS FAR SUPERIOR AS THE GFS CONTINUES TO
HAVE IT`S PROBLEMS WITH THESE DROUGHT CONDITIONS REGARDING
TEMPERATURE OUTPUT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 300 AM EDT WED JUL 25 2012
FOCUS TO THE SHORT TERM WILL BE WITH TIMING AND COVERAGE OF
THUNDERSTORMS AS A CANADIAN PRAIRIE UPPER LOW DROPS SOUTHEAST TO
NEAR LAKE SUPERIOR AS IT OPENS UP AND CONTINUES TO DROP SOUTHEAST ON
FRIDAY. THE FLOW AROUND THE BASE OF THIS FEATURE WILL BE FAST AND
ZONAL THURSDAY BEFORE A DISTURBANCE BUCKLES THE FLOW FRIDAY. THIS
FLOW WILL PUSH A COLD FRONT ACROSS THURSDAY NIGHT AND A REINFORCING
ONE ON FRIDAY. SHOULD SEE DRY WEATHER TONIGHT AND THEN DECENT
THUNDERSTORM CHANCES THURSDAY AND THURSDAY EVENING WITH LINGERING
CHANCES WITH THE SECOND FRONT MAINLY EAST ON FRIDAY AS DEEPER
MOISTURE MOVES INTO OHIO. 90 KNOT JET 250 KNOT JET ACROSS THE GREAT
LAKES...50 KNOT JET ACROSS NORTHERN INDIANA AND 25 KNOT LOW LEVEL
FLOW ALONG WITH MIXED LAYER CAPES AROUND 2000 J/KG WILL HELP THINGS
ALONG AND JUSTIFY SPC DAY2 SLIGHT RISK. UNIDIRECTIONAL FLOW AND
FREEZING LEVELS ABOVE 15K FEET SUGGEST WIND DAMAGE WILL BE THE MAIN
THREAT. FRIDAY NIGHT SHOULD BE DRY AND COOLER WITH OVERNIGHT LOWS IN
THE 60S AS HIGH PRESSURE BUILDS IN FROM THE PLAINS.
A BIG CHANGE IN TEMPERATURES WILL OCCUR BEHIND THE CANADIAN SYSTEM
BY FRIDAY NIGHT BUT NOT BEFORE TWO MORE DAYS OF 90 PLUS DEGREES. MAY
NEED TO GO WITH A HEAT ADVISORY FOR THURSDAY ACROSS OUR SOUTHWEST
COUNTIES...BUT FOR NOW...THE HEAT ADVISORY ACROSS THE SOUTHWEST WILL
EXPAND TO ALL COUNTIES LATER TODAY...AND ANY OTHER WORDING MAY CAUSE
CONFUSION. WILL CONTINUE TO FAVOR THE HOTTER AND MORE IN TUNED NAM
MOS THROUGH FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ISSUED AT 253 AM EDT WED JUL 25 2012
INITIALIZATION HAD RELATIVELY FEW ISSUES THIS MORNING. LONG TERM
WILL BEGIN WITH A DRY PERIOD AS HIGH PRESSURE TRAVERSES THE REGION.
MODEL DISCREPANCIES EXIST LATER IN THE PERIOD AS SUBTLE DISTURBANCES
AND A POSSIBLE BOUNDARY MAY PROVIDE OPPORTUNITIES FOR
THUNDERSTORMS...BUT FELT POPS WERE BEST CAPPED AT 20 TO 30 PERCENT
IN LIGHT OF THIS SIGNIFICANT UNCERTAINTY. TWEAKED MAX TEMPS UPWARD A
BIT MOST PERIODS TO ACCOUNT FOR CONTINUING DROUGHT AND INFLUENCE OF
COOL BIASED GFS.
&&
.AVIATION /DISCUSSION FOR THE 25/12Z TAFS/...
ISSUED AT 659 AM EDT WED JUL 25 2012
VFR THROUGH THE PERIOD OUTSIDE OF ANY POSSIBLE THUNDERSTORMS.
WARM FRONT THAT HAD BEEN BRIEFLY STALLED TO OUR SOUTHWEST WILL LIFT
BACK NORTHEAST TODAY...WITH THE POSSIBILITY OF THUNDERSTORMS MAINLY
ALONG AND NEAR THE BOUNDARY. HRRR AND SREF PROBABILITIES INDICATE
POTENTIAL FOR THUNDERSTORMS MOST OF THE DAY...BUT WITH LACK OF
ORGANIZATION CANNOT GO WITH MORE THAN A VICINITY MENTION THROUGH THE
PEAK HEATING HOURS. WILL HAVE AN INITIAL VICINITY MENTION
LAF/HUF...NEARER WHERE ISOLATED SHOWERS HAVE BEEN POPPING UP THROUGH
THE MORNING.
WINDS WILL BECOME SOUTHWESTERLY BEHIND THE FRONT...IN THE 15KT
RANGE. CANNOT RULE OUT A FEW GUSTS TO 20KT RANGE...BUT THESE WOULD
BE EXTREMELY SPORADIC.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
INZ021-028>031-035>049-054>057-063>065-071-072.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ051>053-060>062-
067>070.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....NIELD
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
720 PM CDT THU JUL 26 2012
.AVIATION...
A WEAK SURFACE BOUNDARY OVER MN AND NRN WI WILL DROP SOUTH THROUGH
THE FORECAST AREA TONIGHT. MID LEVEL CLOUDS BASED AOA 10KFT
ARE EXPECTED TO ACCOMPANY THE BOUNDARY AND SOME ISOLATED SHRA ARE
POSSIBLE IN THE NORTHERN SECTIONS OF THE FORECAST AREA. FRIDAY
MUCH DRIER AIR WILL BE INPLACE WITH SOME SCATTERED FAIR WEATHER CU
EXPECTED BY LATE MORNING AND WINDS REMAINING OUT OF THE NORTHWEST
AT 10 TO 15 KNOTS.
DLF
&&
.PREV DISCUSSION... /ISSUED 333 PM CDT THU JUL 26 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN 850MB COLD FRONT FROM NORTHERN WISCONSIN
SOUTHWEST INTO THE OKLAHOMA PANHANDLE. SEVERAL TROFS WERE ACROSS
THE NORTHERN PLAINS BEHIND THE 850MB COLD FRONT. RADAR/SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW DIURNAL CONVECTION HAS DEVELOPED
FROM SOUTHERN WISCONSIN INTO SOUTHEAST IOWA.
18Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM KVOK BACK TO KRSL. THIS
BOUNDARY MAY BE A VERY DIFFUSE COLD FRONT AS DEW POINTS QUICKLY
DROP INTO THE UPPER 50S AND LOWER 60S BEHIND THE BOUNDARY. AHEAD
OF THE FRONT/BOUNDARY DEW POINTS WERE IN THE LOW 70S.
SHORT TERM...TONIGHT AND FRIDAY
AN AREA OF DIFFERENTIAL HEATING ALONG THE FRONT/BOUNDARY HAS
ALLOWED CONVECTIVE TEMPERATURE TO BE ACHIEVED.
RAP TRENDS INDICATE THE CURRENT CONVECTION WILL REMAIN ISOLATED
OVER SOUTHEAST IOWA AND MORE SCATTERED FROM THE QUAD CITIES TO THE
NORTH AND EAST. RAP TRENDS INDICATE THIS CONVECTION WILL PERSIST
INTO THE LATE AFTERNOON AND EARLY EVENING IN THE FAR EASTERN AND
SOUTHERN SECTIONS OF THE CWFA.
THE APPROACHING SHORTWAVE ACROSS MINNESOTA IS ALLOWING CU TO
DEVELOP FROM SOUTHERN MINNESOTA INTO NORTHERN IOWA. RADAR SHOWS NO
CONVECTION AS YET BUT WITH PEAK HEATING OCCURRING CONVECTION MAY
DEVELOP IN THE NEXT COUPLE OF HOURS. IF THIS OCCURS...THEN IT MAY
GET INTO THE HWY 20 CORRIDOR THIS EVENING. NEARLY ALL CONVECTION
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNSET. HOWEVER...
CONVECTION DID PERSIST OVERNIGHT CLOSE TO THE SFC LOW AND UPPER
LOW. THUS IT IS POSSIBLE THAT SOME ISOLATED SHRA/TSRA MAY PERSIST
PAST MIDNIGHT THAT CATCHES THE NORTHEAST PART OF THE CWFA.
FRIDAY IS LOOKING TO BE QUITE NICE WITH TEMPERATURES NEAR NORMAL.
HUMIDITY LEVELS WILL ALSO BE LOW. ..08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
HIGH PRESSURE BUILDS INTO THE REGION FRIDAY NIGHT AND SATURDAY TO
KEEP THINGS QUIET BOTH PERIODS. HOWEVER...SATURDAY NIGHT AND SUNDAY
A NICE WARM AIR ADVECTION SURGE WITH A WEAK SHORTWAVE MOVES ACROSS
THE AREA TO BRING SOME PRECIPITATION CHANCES TO THE AREA.
TEMPERATURES WILL BE COOLER THAN WHAT WE HAVE HAD RECENTLY...WITH
HIGHS IN THE 80S TO AROUND 90 BOTH DAYS.
SUNDAY NIGHT THROUGH MONDAY NIGHT A STRONGER SHORTWAVE COMES ALONG
TO INTERACT WITH A WEAK 850MB BAROCLINIC ZONE TO BRING SOME
PRECIPITATION CHANCES TO THE AREA. THERE IS ROUGH AGREEMENT WITH
THE MODELS...BUT WITH TIMING DIFFERENCES TO ADD SOME CONFUSION.
HIGHS MONDAY TO BEGIN CREEPING UP...RISING INTO THE MID 80S TO LOW
90S.
TUESDAY THROUGH WEDNESDAY MODELS ARE IN GENERAL AGREEMENT THAT A
SURFACE RIDGE WILL BUILD ACROSS THE REGION...WHICH IS NOT ESPECIALLY
FAVORABLE FOR PRECIPITATION CHANCES...SO HAVE KEPT THOSE DRY OR AT
MOST SLIGHT CHANCE. HIGHS REMAIN IN THE 80S TO LOW 90S WITH THE
CONTINUING NORTHWEST FLOW ALOFT AND ENOUGH MOISTURE AT MID LEVELS TO
PRODUCE SOME MID CLOUDS.
THURSDAY WE HAVE A WEAK COLD FRONT AND HINTS AT AN UPPER LEVEL
SHORTWAVE TO MOVE THROUGH THE AREA...THOUGH MODELS HAVE A LOT OF
DIFFERENCES AND CONFIDENCE IS NOT VERY HIGH. HOWEVER...IT WAS
ENOUGH TO PUT IN TO CARRY SOME LOW END CHANCE POPS.
LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
337 PM CDT WED JUL 25 2012
.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...25/18Z
STRONG SOUTHWEST FLOW AND DEEP MIXING WILL CONTINUE AHEAD OF THE
COLD FRONT THROUGH THE LATE AFTERNOON/EARLY EVENING. HAVE LOW
CONFIDENCE WITH TIMING AND LOCATION OF CONVECTION WITH THE FRONT
MOVING THROUGH. LATEST 4.0KM WRF-NMM SUGGEST SPOTTY CONVECTION ALONG
AND BEHIND THE FRONT...SO JUST HAVE MENTION OF VCTS ATTM.
OTHERWISE...WINDS BEGIN TO MIX AGAIN OUT OF THE WEST NORTHWEST
TOMORROW LATE IN THE MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT
ADAIR-ADAMS-APPANOOSE-AUDUBON-BOONE-CALHOUN-CARROLL-CASS-CLARKE-
CRAWFORD-DALLAS-DAVIS-DECATUR-GREENE-GUTHRIE-HAMILTON-JASPER-LUCAS-
MADISON-MAHASKA-MARION-MONROE-POLK-RINGGOLD-SAC-STORY-TAYLOR-UNION-
WAPELLO-WARREN-WAYNE-WEBSTER
HEAT ADVISORY UNTIL 7 PM CDT
BLACK HAWK-BREMER-BUTLER-FRANKLIN-GRUNDY-HARDIN-HUMBOLDT-MARSHALL-
POCAHONTAS-POWESHIEK-TAMA-WRIGHT
&&
$$
SHORT TERM/AVIATION...PODRAZIK
LONG TERM...SMALL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1233 PM CDT WED JUL 25 2012
.AVIATION...
VFR WX WILL BE SEEN THROUGH 00Z/26. HOWEVER...DENSITY ALTITUDES
WILL BE 3-4 KFT THROUGH AT LEAST 01Z/26. A COLD FRONT WILL BEGIN
TO SLOWLY MOVE THROUGH EASTERN IOWA AND NORTHERN ILLINOIS STARTING
AROUND 00Z/26. KCID/KDBQ HAVE THE BEST CHANCE AT SEEING A TSRA
WITH MVFR CONDITIONS. THE FRONT IS FORECAST TO WEAKEN AFT SUNSET
SO THE POTENTIAL FOR TSRA AT KMLI/KBRL ARE MORE UNCERTAIN. VFR
CONDITIONS ARE EXPECTED TO CONTINUE AFT 00Z/26 WITH THE POTENTIAL
FOR SHRA WITH POSSIBLY SOME TSRA. ...08..
&&
.PREV DISCUSSION... /ISSUED 1101 AM CDT WED JUL 25 2012/
UPDATE...
DATA THROUGH 15Z INDICATES THAT THE INVERSION IS ESSENTIALLY GONE.
WINDS ARE STARTING TO INCREASE PER SFC OBS. INTERESTINGLY...DEW
POINTS HAVE INCREASED SINCE SUNRISE. THIS INCREASE IS PARTIALLY
DUE TO THE CORN STARTING TO ACTIVELY EVAPOTRANSPIRATE BUT IT IS
ALSO A RESULT OF POOLING ALONG A FRONT/BOUNDARY MOVING THROUGH THE
CWFA.
RAP TRENDS INDICATE THIS FRONT/BOUNDARY WILL EXIT THE CWFA IN THE
NEXT FEW HOURS ALLOWING TEMPERATURES ACROSS THE NORTH TO QUICKLY
WARM. AS THE FRONT/BOUNDARY LEAVES THE AREA...DEW POINTS SHOULD
SLOWLY DROP AS DEEPER MIXING OF THE ATMOSPHERE OCCURS. THE HIGH
THIN CI/CS IS A CONCERN ACROSS THE NORTHERN CWFA AS IT COULD
SUPPRESS TEMPERATURES TODAY.
ATTENTION THEN TURNS TO PRECIP CHANCES LATER TODAY. RAP TRENDS
GENERALLY HAVE CONVECTIVE TEMPERATURES AT OR ABOVE 103. AS SUCH
CONVECTION SHOULD BE DELAYED UNTIL VERY LATE IN THE AFTERNOON.
REAL AND MODEL DATA CONTINUES TO SUPPORT AN ANAFRONT WITH PRECIP
ALONG/BEHIND THE FRONT. IF RAP TRENDS FROM THE LIFT TOOL AND
GENERAL ISENTROPICS ON THE 335K THETA SFC CONTINUE...
PRECIPITATION MAY NOT BEGIN IN THE HWY 20 CORRIDOR WEST OF DUBUQUE
UNTIL ROUGHLY 6 OR 7 PM. AS SUCH THE FCST HAS PUSHED BACK THE
START OF ANY CONVECTION UNTIL 5 PM. THESE TRENDS WILL NEED TO BE
MONITORED THROUGH THE AFTERNOON.
THE HEAT HEADLINES WILL CONTINUE. ANY REFINEMENTS TO THE AREAL AND
TEMPORAL COVERAGE WILL BE ADDRESSED THIS AFTERNOON.
MODEL TRENDS CONTINUE TO SHOW THE OVERALL FORCING BECOMING WEAKER
AFTER SUNSET. SUCH A TREND IS DISTURBING AS IT WOULD SUGGEST NOT
MUCH IN THE WAY OF RAIN TONIGHT. ..08..
CLIMATE...
RECORD HIGHS FOR JULY 25...
BURLINGTON.....107 IN 1936
CEDAR RAPIDS...105 IN 1940
DUBUQUE........102 IN 1940
MOLINE.........105 IN 1940
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA-
JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BUREAU-CARROLL-
HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1101 AM CDT WED JUL 25 2012
.UPDATE...
DATA THROUGH 15Z INDICATES THAT THE INVERSION IS ESSENTIALLY GONE.
WINDS ARE STARTING TO INCREASE PER SFC OBS. INTERESTINGLY...DEW
POINTS HAVE INCREASED SINCE SUNRISE. THIS INCREASE IS PARTIALLY
DUE TO THE CORN STARTING TO ACTIVELY EVAPOTRANSPIRATE BUT IT IS
ALSO A RESULT OF POOLING ALONG A FRONT/BOUNDARY MOVING THROUGH THE
CWFA.
RAP TRENDS INDICATE THIS FRONT/BOUNDARY WILL EXIT THE CWFA IN THE
NEXT FEW HOURS ALLOWING TEMPERATURES ACROSS THE NORTH TO QUICKLY
WARM. AS THE FRONT/BOUNDARY LEAVES THE AREA...DEW POINTS SHOULD
SLOWLY DROP AS DEEPER MIXING OF THE ATMOSPHERE OCCURS. THE HIGH
THIN CI/CS IS A CONCERN ACROSS THE NORTHERN CWFA AS IT COULD
SUPPRESS TEMPERATURES TODAY.
ATTENTION THEN TURNS TO PRECIP CHANCES LATER TODAY. RAP TRENDS
GENERALLY HAVE CONVECTIVE TEMPERATURES AT OR ABOVE 103. AS SUCH
CONVECTION SHOULD BE DELAYED UNTIL VERY LATE IN THE AFTERNOON.
REAL AND MODEL DATA CONTINUES TO SUPPORT AN ANAFRONT WITH PRECIP
ALONG/BEHIND THE FRONT. IF RAP TRENDS FROM THE LIFT TOOL AND
GENERAL ISENTROPICS ON THE 335K THETA SFC CONTINUE...
PRECIPITATION MAY NOT BEGIN IN THE HWY 20 CORRIDOR WEST OF DUBUQUE
UNTIL ROUGHLY 6 OR 7 PM. AS SUCH THE FCST HAS PUSHED BACK THE
START OF ANY CONVECTION UNTIL 5 PM. THESE TRENDS WILL NEED TO BE
MONITORED THROUGH THE AFTERNOON.
THE HEAT HEADLINES WILL CONTINUE. ANY REFINEMENTS TO THE AREAL AND
TEMPORAL COVERAGE WILL BE ADDRESSED THIS AFTERNOON.
MODEL TRENDS CONTINUE TO SHOW THE OVERALL FORCING BECOMING WEAKER
AFTER SUNSET. SUCH A TREND IS DISTURBING AS IT WOULD SUGGEST NOT
MUCH IN THE WAY OF RAIN TONIGHT. ..08..
&&
.AVIATION...
VFR WX WILL BE SEEN THROUGH 00Z/26. DENSITY ALTITUDES HAVE
INCREASED TO 3 KFT AND WILL BE 3-4 KFT THROUGH AT LEAST 00Z/26.
AFT 00Z/26 A COLD FRONT WILL SLOWLY MOVE THROUGH THE AREA BRINGING
A THREAT OF TSRA. THERE IS A POTENTIAL FOR MVFR CONDITIONS IF A
TSRA AFFECTS A TAF SITE. ..08..
&&
.CLIMATE...
RECORD HIGHS FOR JULY 25...
BURLINGTON.....107 IN 1936
CEDAR RAPIDS...105 IN 1940
DUBUQUE........102 IN 1940
MOLINE.........105 IN 1940
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-
LINN-MUSCATINE-SCOTT.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR DES MOINES-HENRY
IA-JEFFERSON-KEOKUK-LEE-LOUISA-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BUREAU-CARROLL-
HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-
WHITESIDE.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
MCDONOUGH-WARREN.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
247 PM MDT WED JUL 25 2012
.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 AIRMASS 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 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1101 AM MDT WED JUL 25 2012
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
FROM THE SOUTHWEST TO THE NORTHEAST EARLY IN THE TAF PERIOD.
THUNDERSTORMS WILL INCREASE IN COVERAGE AS UPPER LEVEL DISTURBANCE
SHIFTS SOUTH AND EAST OVER THE AREA...WITH THUNDERSTORM ACTIVITY
POSSIBLY IMPACTING TERMINALS LATE THIS AFTERNOON AND EARLY THIS
EVENING. GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON AND
THEN DECREASE BY THIS EVENING AS FRONTAL ZONE SHIFTS SOUTHEAST.
MVFR CONDITIONS IS POSSIBLE LATE TONIGHT/EARLY THURSDAY MORNING AT
KMCK AS A RESULT OF PATCHY FOG DEVELOPING UNDER SURFACE HIGH
PRESSURE. CONFIDENCE WAS TOO LOW TO PREVAIL THESE CONDITIONS AT
THIS TAF ISSUANCE...SO LEFT VIS/CIGS VFR FOR NOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1241 PM MDT WED JUL 25 2012
.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 FRONTOGENISIS 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 AIRMASS SUPPORTING
RADIATIVE FOG DEVELOPMENT. GUIDANCE REALLY HASNT PICKED UP ON THIS
YET...SO I HAVE LEFT FOG COVERAGE LIMITED TO PATCHY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS
THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT
THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND
A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND
IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG
UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE
ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE
AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS
MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE
EXPECTED PATTERN PRETTY WELL.
THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST
AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL
MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH
DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED
AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE
WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH
POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE
RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1101 AM MDT WED JUL 25 2012
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
FROM THE SOUTHWEST TO THE NORTHEAST EARLY IN THE TAF PERIOD.
THUNDERSTORMS WILL INCREASE IN COVERAGE AS UPPER LEVEL DISTURBANCE
SHIFTS SOUTH AND EAST OVER THE AREA...WITH THUNDERSTORM ACTIVITY
POSSIBLY IMPACTING TERMINALS LATE THIS AFTERNOON AND EARLY THIS
EVENING. GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON AND
THEN DECREASE BY THIS EVENING AS FRONTAL ZONE SHIFTS SOUTHEAST.
MVFR CONDITIONS IS POSSIBLE LATE TONIGHT/EARLY THURSDAY MORNING AT
KMCK AS A RESULT OF PATCHY FOG DEVELOPING UNDER SURFACE HIGH
PRESSURE. CONFIDENCE WAS TOO LOW TO PREVAIL THESE CONDITIONS AT
THIS TAF ISSUANCE...SO LEFT VIS/CIGS VFR FOR NOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM/PMM
AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1209 PM CDT WED JUL 25 2012
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 418 AM CDT WED JUL 25 2012
AN INTENSE UPPER LOW OVER THE SOUTHERN CANADIAN PRAIRIES CONTINUED
TO MOVE SLOWLY EAST DURING THE OVERNIGHT HOURS. THERE WERE TWO LOWS
EVIDENT AT 850MB IN THE 25.00Z ANALYSIS. THE NORTHERN LOW WAS WELL
INTO CANADA NEAR SASKATOON, SASKATCHEWAN. FARTHER SOUTH IN THE
CONUS...A LOW WAS CENTERED EAST OF THE BLACK HILLS OF SOUTH DAKOTA.
A FAIRLY INTENSE TEMPERATURE GRADIENT WAS NOTED ACROSS SOUTH DAKOTA
WITH +20C AT BISMARCK, ND AND +31C NOSING INTO SOUTH CENTRAL SD PER
THE RAP ANALYSIS. SEVERAL CLUSTERS OF THUNDERSTORMS DEVELOPED ACROSS
SOUTH DAKOTA ALONG THIS BAROCLINIC ZONE, WITH A LARGE MCS ROLLING
ACROSS NORTHERN MINNESOTA AS OF 08Z. ELSEWHERE...A SUBTLE BUT
IMPORTANT SHORTWAVE TROUGH COULD BE PICKED OUT IN THE RAP ANALYSIS
AND WATER VAPOR IMAGERY MOVING EAST THROUGH UTAH AND SOUTHWESTERN
WYOMING...MOVING INTO WESTERN/NORTHWESTERN COLORADO. A SURFACE COLD
FRONT AS OF 08Z EXTENDED FROM NORTH CENTRAL NEBRASKA TO NORTHEASTERN
COLORADO. SURFACE WINDS BEHIND THE FRONT IN EASTERN COLORADO AND
THE NEBRASKA PANHANDLE WERE NORTHWEST 20 TO 25 KNOTS WITH SOME GUSTS
IN SOME PLACES EXCEEDING 30 KNOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 418 AM CDT WED JUL 25 2012
THE MAIN CHALLENGE IN THE FORECAST PERTAINS TO THUNDERSTORM CHANCES,
STRENGTH, AND LOCATION OF THOSE BEST CHANCES LATER ON THIS AFTERNOON
AND TONIGHT AS THE COLD FRONT REACHES SOUTHWEST KANSAS. 850MB TEMPS
AHEAD OF THE FRONT UP TO +31C SUGGEST ANOTHER DAY OF HIGHS IN THE
103 TO 106F RANGE WITH THE NORTHERN FORECAST AREA SEEING THE HOTTEST
TEMPERATURES AGAIN...MUCH LIKE THE PAST FEW DAYS. IF THE STORMS HOLD
OFF LONG ENOUGH...HAYS COULD REACH 108F AGAIN LIKE YESTERDAY.
INITIAL THUNDERSTORMS SHOULD DEVELOP AS SURFACE TEMPERATURES
APPROACH CONVECTIVE TEMPERATURE ALONG AN AXIS FROM ROUGHLY ELKHART
TO SYRACUSE TO WAKEENEY-GOVE AREAS. OTHER STORMS MAY FORM FARTHER
EAST TIED TO A WEAK MID LEVEL VORTICITY ANOMALY THAT WILL MOVE
SLOWLY EAST ACROSS SOUTHWEST KANSAS DURING THE AFTERNOON. THESE
STORMS SHOULD BE ALL THAT STRONG SINCE LOW LEVEL CONVERGENCE WILL BE
ESSENTIALLY NON-EXISTENT (REMAINING FARTHER NORTH).
THE MOST ORGANIZED THUNDERSTORMS WILL DEVELOP IN THE 22-00Z TIME
FRAME FROM ROUGHLY LAKIN TO SCOTT CITY TO WAKEENEY. THESE STORMS
WILL ADVANCE SLOWLY SOUTHEAST THROUGH THE EVENING HOURS WITH
SUBSEQUENT DEVELOPMENT OF STORMS FORMING ON VARIOUS COLD POOL
INTERACTIONS WHICH ARE IMPOSSIBLE TO PREDICT. IT IS UNCLEAR WHETHER
A SMALL MCS MAY DEVELOP AND THRIVE PAST THE ~04Z TIME FRAME...AS LOW
LEVEL MOISTURE, WHILE ADEQUATE IN THE UPPER 50S TO LOWER 60S...WILL
NOT BE NEAR WHAT THE GFS MODEL IS SUGGESTING (A CHRONIC PROBLEM WITH
THIS MODEL ALL SEASON). THE SHORTWAVE TROUGH MENTIONED IN THE
SYNOPSIS SECTION ENTERING COLORADO WILL AID IN SOME INCREASED DEEP
UPWARD VERTICAL MOTION LATE TONIGHT...BUT BY THE TIME THAT REACHES
WESTERN KANSAS...MUCH OF THE CONVECTIVE ACTIVITY WILL LIKELY HAVE
SHIFTED EAST INTO CENTRAL KANSAS.
AS FAR AS THE POP FORECAST GOES...WILL BE INCREASING THE POPS TO
50-60 PERCENT NORTH OF A GARDEN CITY TO LARNED LINE TO INTERSTATE 70
CORRIDOR. AS FAR AS THE SEVERE WEATHER POTENTIAL GOES...THERE IS
DEFINITELY A CHANCE AT AT LEAST SOME ISOLATED SEVERE WIND REPORTS
GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS. STRONG UPDRAFTS
ARE QUITE LIKELY GIVEN THE STRONG LOW LEVEL CONVERGENCE WITH THE
SLOW MOVING FRONT. THIS WILL LEAD TO INTENSE DOWNDRAFTS AND EVEN A
FEW SEVERE MICROBURSTS. THE HAIL THREAT IS RATHER LOW CONSIDERING
THE POOR VERTICAL WIND SHEAR AND OVERALL WARM MID LEVEL TEMPERATURES
AS WELL AS HIGH MELTING AND -20C LEVELS. WILL BE DECREASING POPS
ACROSS MUCH OF THE FORECAST AREA DURING THE 06-12Z TIME FRAME WITH
COLD ADVECTION TAKING OVER IN THE LOW LEVELS AS THE SYNOPTIC FRONT
CONTINUES SOUTHEAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 234 AM CDT WED JUL 25 2012
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
DEVELOPING ACROSS THE FAR INTERMOUNTAIN WEST TODAY AND DRIFTING
SLOWLY EAST ACROSS THE ROCKIES TO BEGIN THE PERIOD THURSDAY. IT
WILL MOVE FURTHER INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND
QUICKLY BRINGING A GENERALLY DRIER WEATHER PATTERN BACK TO
WESTERN KANSAS DURING MUCH OF THE PERIOD. AIDING THIS DRIER
PATTERN WILL BE A FAIRLY WEAK FLOW ALOFT ASSOCIATED WITH THE
UPPER LEVEL RIDGING.
TEMPERATURES ARE EXPECTED TO BE MORE SEASONAL THURSDAY IN WAKE OF
A COLD FRONTAL PASSAGE LATE WEDNESDAY. A NORTH TO NORTHEAST LOW
LEVEL FLOW WILL PREVAIL ACROSS WESTERN KANSAS THURSDAY HELPING TO
LOWER H85 TEMPERATURES EVER SO SLIGHTLY WITH VALUES GENERALLY
RANGING FROM THE MID 20S(C) ACROSS CENTRAL KANSAS TO THE UPPER
20S(C) IN EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS ONLY UP INTO
THE 90S(F) THURSDAY AFTERNOON. A GRADUAL WARMING TREND IS STILL
EXPECTED INTO THE WEEKEND AS THE AFOREMENTIONED UPPER LEVEL
RIDGING APPROACHES FROM THE INTERMOUNTAIN WEST BY THURSDAY AND
BEGINS TO PUSH EAST INTO THE WESTERN HIGH PLAINS THROUGH THE
WEEKEND. SHOULD SEE HIGHS CLIMBING UP NEAR TO JUST ABOVE 100F BY
THE CLOSE OF THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1155 AM CDT WED JUL 25 2012
A COLD FRONT WILL MOVE ACROSS THE TAF SITES BETWEEN 01-03Z THIS
EVENING WITH A CHANCE FOR THUNDERSTORMS. THUNDERSTORM CHANCES
DIMINISH AFTER 06-08Z TONIGHT AS THE COLD FRONT CONTINUES
SOUTHEASTWARD. SOME STORMS COULD PRODUCE WIND GUSTS TO 40 KT AND
SMALL HAIL TO DIME SIZE. SOUTHERLY WINDS OF 15-22 KT WILL SHIFT
TO NORTH TO NORTHEASTERLY 10-22 KT. EXPECT VFR CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 104 69 96 67 / 30 40 10 0
GCK 103 67 95 66 / 40 50 10 0
EHA 102 67 93 67 / 30 30 10 0
LBL 104 68 95 67 / 30 30 10 0
HYS 106 68 95 67 / 40 60 10 0
P28 103 74 98 71 / 20 40 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1101 AM MDT WED JUL 25 2012
.UPDATE...
ISSUED AT 457 AM MDT WED JUL 25 2012
ELEVATED THUNDERSTORMS HAVE DEVELOPED FARTHER TO THE EAST THAN
PREVIOUSLY EXPECTED...BEING DRIVEN BY ELEVATED FRONTAL ZONE AROUND
H8 AND POCKET OF WEAKLY CAPPED INSTABILITY IN BTWN H75 AND H65.
WHILE PRECIP COVERAGE HAS BEEN SPOTTY...MCK MEASURED A QUICK 0.2
OF RAIN IN ABOUT 15 MINUTES AS STORM PASSED. RAP INDICATES AREA OF
ELEVATED INSTABILITY SHIFTS TO THE NORTH AND DIMINISHES DURING
THE MORNING HOURS...BUT THINK A STORM OR TWO MAY CONTINUE TO
DEVELOP ALONG ELEVATED FRONT THIS MORNING AS SATELLITE INDICATING
LINEAR BAND OF COOLING CLOUD TOPS DEVELOPING FROM GOODLAND TO
NORTON. AM A LITTLE CONCERNED ABOUT ANOTHER POCKET OF ELEVATED
INSTABILITY ASSOCIATED WITH WEAK SHORT WAVE TROUGH THAT HAS BEEN
DRIFTING TO THE NORTH AND WOULD NOT BE OUT OF THE QUESTION TO SEE
A CELL OR TWO ALONG SOUTHERN FRINGE OF CWA AS FRONT INTERACTS WITH
THIS AREA. NOT REALLY SEEING ANY SIGNS OF THIS ON SATELLITE RIGHT
NOW AND WOULD LIKE TO SEE SOME CONFIRMATION WITH MORNING SOUNDINGS
BEFORE CHANGING FORECAST GREATLY. ASIDE FROM EARLY MORNING
CONVECTION...REST OF FORECAST STILL ON TRACK
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
03Z WATER VAPOR IMAGERY INDICATED LARGE AREA OF SUBSIDENCE/DRYING
THAT WAS OVER THE AREA THE PAST FEW DAYS HAD SHIFTED TO THE
NORTHEAST...WITH SUBTLE SHORT WAVE TROUGH MOVING ACROSS SOUTHERN
KANSAS WITH STRONG SHORT WAVE TROUGH MOVING ACROSS THE US/CANADIAN
BORDER. 00Z RAOBS SHOWED LITTLE CHANGE IN THERMAL PROFILES ACROSS
THE AREA WITH LARGEST CHANGES NOTED AT DDC WHERE TEMPS BELOW H7 HAS
WARMED AROUND 2C AND TEMPS BTWN H7 AND H5 HAD COOLED AROUND 2C.
PRIMARY FORECAST CONCERN WILL BE PRECIPITATION CHANCES TODAY AND
TONIGHT...FOLLOWED BY TEMPS THROUGH THE START OF THE WEEKEND.
TODAY...COLD FRONT IS CURRENTLY ADVANCING ACROSS THE CWA AND WILL
CONTINUE TO ADVANCE TO THE SOUTH BEFORE STALLING ACROSS SOUTHERN
PORTION OF THE CWA LATE THIS MORNING. ALREADY SEEING A FEW SHOWERS
AND THUNDERSTORMS POP UP BEHIND THE FRONT...ALTHOUGH PRECIP AMOUNTS
LOOK TOP BE VERY SPOTTY AS UPDRAFTS REMAIN WEAK AND SHORT LIVED.
POCKET OF LOW CINH AND WEAK INSTABILITY LOCATED AROUND H7 AND AREA
OF FRONTOGENESIS LINE UP WITH CURRENT ACTIVITY PRETTY WELL AND
GENERAL TRENDS WITH THESE FIELDS SUGGEST ACTIVITY SHOULD REMAIN
CONFINED TO THE NORTHWESTERN CWA DURING THE MORNING HOURS. LARGE
SCALE FORCING FOR ASCENT BEGINS TO INCREASE AS SHORT WAVE TROUGH
APPROACHES NEB PANHANDLE AND DRIFTS TO THE SOUTHEAST. INITIALLY
THOUGHT THAT PRECIPITATION WOULD STRUGGLE TO DEVELOP CLOSER TO
STRONGER UPPER LEVEL FORCING AND INSTEAD FAVOR FRONTAL ZONE TO THE
SOUTH BUT SEEING AS LIMITED INSTABILITY ALREADY BEING
REALIZED...THINK COVERAGE WILL IMPROVES AS FORCING
INCREASES...BEFORE SFC FRONT BECOMES PRIMARY FOCUS FOR STORMS LATE
IN THE AFTERNOON.
TONIGHT...BIG QUESTION FOR THE OVERNIGHT PERIOD WILL BE HOW LONG
PRECIPITATION LINGERS ACROSS THE AREA. WHILE PERIOD OF LARGE SCALE
FORCING FOR ASCENT AND MID LEVEL FRONTOGENESIS ARE IN PLACE ACROSS
MUCH OF THE AREA AT 00Z...THESE FIELDS DIMINISH CONSIDERABLY DURING
THE EVENING HOURS AND THINK BULK OF PRECIPITATION WILL BE TIED TO
FRONTAL ZONE WHICH WILL BE MOVING QUICKLY OUT OF THE CWA. WHILE
INITIAL THOUGHTS ARE MUCH OF THE CWA WILL BE DONE WITH PRECIPITATION
AROUND 00Z...HAVE SOME CONCERNS THAT SOUNDINGS INDICATE SOME
POTENTIAL DESTABILIZATION ACROSS EASTERN COLORADO AFTER FRONT
PASSES. NOT SURE I CAN PUT REALLY GREAT CONFIDENCE INTO THIS
SOLUTION...BUT WITH LATEST GEFS AS WELL AS LOCAL NEIGHBORHOOD
PRECIPITATION GUIDANCE THINK LINGERING HIGHER POPS INTO AT LEAST 2Z
IS WARRANTED.
TOMORROW...NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ACROSS THE AREA
AS H5 RIDGE AMPLIFIES OVER THE ROCKIES WITH SFC HIGH BRINGING FAIRLY
LIGHT AND VARIABLE WINDS ACROSS THE CWA. WHILE THERE IS NOT IN THE
WAY OF LARGE SCALE FORCING...GENERAL MODELS INDICATE SFC HEATING
WILL BE ENOUGH TO REMOVE MUCH OF THE CINH ASSOCIATED WITH
INSTABILITY AXIS THAT DEVELOPS ACROSS COLORADO. NOT REALLY CONFIDENT
IN PRECIP CHANCES OR COVERAGE...BUT THINK CURRENT ISOLATED CHANCES
IN THIS AREA LOOK REASONABLE ATTM.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS
THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT
THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND
A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND
IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG
UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE
ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE
AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS
MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE
EXPECTED PATTERN PRETTY WELL.
THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST
AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL
MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH
DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED
AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE
WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH
POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE
RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1101 AM MDT WED JUL 25 2012
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE
FROM THE SOUTHWEST TO THE NORTHEAST EARLY IN THE TAF PERIOD.
THUNDERSTORMS WILL INCREASE IN COVERAGE AS UPPER LEVEL DISTURBANCE
SHIFTS SOUTH AND EAST OVER THE AREA...WITH THUNDERSTORM ACTIVITY
POSSIBLY IMPACTING TERMINALS LATE THIS AFTERNOON AND EARLY THIS
EVENING. GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON AND
THEN DECREASE BY THIS EVENING AS FRONTAL ZONE SHIFTS SOUTHEAST.
MVFR CONDITIONS IS POSSIBLE LATE TONIGHT/EARLY THURSDAY MORNING AT
KMCK AS A RESULT OF PATCHY FOG DEVELOPING UNDER SURFACE HIGH
PRESSURE. CONFIDENCE WAS TOO LOW TO PREVAIL THESE CONDITIONS AT
THIS TAF ISSUANCE...SO LEFT VIS/CIGS VFR FOR NOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...JRM
LONG TERM...JRM/PMM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
548 AM MDT WED JUL 25 2012
.UPDATE...
ISSUED AT 457 AM MDT WED JUL 25 2012
ELEVATED THUNDERSTORMS HAVE DEVELOPED FARTHER TO THE EAST THAN
PREVIOUSLY EXPECTED...BEING DRIVEN BY ELEVATED FRONTAL ZONE AROUND
H8 AND POCKET OF WEAKLY CAPPED INSTABILITY IN BTWN H75 AND H65.
WHILE PRECIP COVERAGE HAS BEEN SPOTTY...MCK MEASURED A QUICK 0.2
OF RAIN IN ABOUT 15 MINUTES AS STORM PASSED. RAP INDICATES AREA OF
ELEVATED INSTABILITY SHIFTS TO THE NORTH AND DIMINISHES DURING
THE MORNING HOURS...BUT THINK A STORM OR TWO MAY CONTINUE TO
DEVELOP ALONG ELEVATED FRONT THIS MORNING AS SATELLITE INDICATING
LINEAR BAND OF COOLING CLOUD TOPS DEVELOPING FROM GOODLAND TO
NORTON. AM A LITTLE CONCERNED ABOUT ANOTHER POCKET OF ELEVATED
INSTABILITY ASSOCIATED WITH WEAK SHORT WAVE TROUGH THAT HAS BEEN
DRIFTING TO THE NORTH AND WOULD NOT BE OUT OF THE QUESTION TO SEE
A CELL OR TWO ALONG SOUTHERN FRINGE OF CWA AS FRONT INTERACTS WITH
THIS AREA. NOT REALLY SEEING ANY SIGNS OF THIS ON SATELLITE RIGHT
NOW AND WOULD LIKE TO SEE SOME CONFIRMATION WITH MORNING SOUNDINGS
BEFORE CHANGING FORECAST GREATLY. ASIDE FROM EARLY MORNING
CONVECTION...REST OF FORECAST STILL ON TRACK
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
03Z WATER VAPOR IMAGERY INDICATED LARGE AREA OF SUBSIDENCE/DRYING
THAT WAS OVER THE AREA THE PAST FEW DAYS HAD SHIFTED TO THE
NORTHEAST...WITH SUBTLE SHORT WAVE TROUGH MOVING ACROSS SOUTHERN
KANSAS WITH STRONG SHORT WAVE TROUGH MOVING ACROSS THE US/CANADIAN
BORDER. 00Z RAOBS SHOWED LITTLE CHANGE IN THERMAL PROFILES ACROSS
THE AREA WITH LARGEST CHANGES NOTED AT DDC WHERE TEMPS BELOW H7 HAS
WARMED AROUND 2C AND TEMPS BTWN H7 AND H5 HAD COOLED AROUND 2C.
PRIMARY FORECAST CONCERN WILL BE PRECIPITATION CHANCES TODAY AND
TONIGHT...FOLLOWED BY TEMPS THROUGH THE START OF THE WEEKEND.
TODAY...COLD FRONT IS CURRENTLY ADVANCING ACROSS THE CWA AND WILL
CONTINUE TO ADVANCE TO THE SOUTH BEFORE STALLING ACROSS SOUTHERN
PORTION OF THE CWA LATE THIS MORNING. ALREADY SEEING A FEW SHOWERS
AND THUNDERSTORMS POP UP BEHIND THE FRONT...ALTHOUGH PRECIP AMOUNTS
LOOK TOP BE VERY SPOTTY AS UPDRAFTS REMAIN WEAK AND SHORT LIVED.
POCKET OF LOW CINH AND WEAK INSTABILITY LOCATED AROUND H7 AND AREA
OF FRONTOGENESIS LINE UP WITH CURRENT ACTIVITY PRETTY WELL AND
GENERAL TRENDS WITH THESE FIELDS SUGGEST ACTIVITY SHOULD REMAIN
CONFINED TO THE NORTHWESTERN CWA DURING THE MORNING HOURS. LARGE
SCALE FORCING FOR ASCENT BEGINS TO INCREASE AS SHORT WAVE TROUGH
APPROACHES NEB PANHANDLE AND DRIFTS TO THE SOUTHEAST. INITIALLY
THOUGHT THAT PRECIPITATION WOULD STRUGGLE TO DEVELOP CLOSER TO
STRONGER UPPER LEVEL FORCING AND INSTEAD FAVOR FRONTAL ZONE TO THE
SOUTH BUT SEEING AS LIMITED INSTABILITY ALREADY BEING
REALIZED...THINK COVERAGE WILL IMPROVES AS FORCING
INCREASES...BEFORE SFC FRONT BECOMES PRIMARY FOCUS FOR STORMS LATE
IN THE AFTERNOON.
TONIGHT...BIG QUESTION FOR THE OVERNIGHT PERIOD WILL BE HOW LONG
PRECIPITATION LINGERS ACROSS THE AREA. WHILE PERIOD OF LARGE SCALE
FORCING FOR ASCENT AND MID LEVEL FRONTOGENESIS ARE IN PLACE ACROSS
MUCH OF THE AREA AT 00Z...THESE FIELDS DIMINISH CONSIDERABLY DURING
THE EVENING HOURS AND THINK BULK OF PRECIPITATION WILL BE TIED TO
FRONTAL ZONE WHICH WILL BE MOVING QUICKLY OUT OF THE CWA. WHILE
INITIAL THOUGHTS ARE MUCH OF THE CWA WILL BE DONE WITH PRECIPITATION
AROUND 00Z...HAVE SOME CONCERNS THAT SOUNDINGS INDICATE SOME
POTENTIAL DESTABILIZATION ACROSS EASTERN COLORADO AFTER FRONT
PASSES. NOT SURE I CAN PUT REALLY GREAT CONFIDENCE INTO THIS
SOLUTION...BUT WITH LATEST GEFS AS WELL AS LOCAL NEIGHBORHOOD
PRECIPITATION GUIDANCE THINK LINGERING HIGHER POPS INTO AT LEAST 2Z
IS WARRANTED.
TOMORROW...NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ACROSS THE AREA
AS H5 RIDGE AMPLIFIES OVER THE ROCKIES WITH SFC HIGH BRINGING FAIRLY
LIGHT AND VARIABLE WINDS ACROSS THE CWA. WHILE THERE IS NOT IN THE
WAY OF LARGE SCALE FORCING...GENERAL MODELS INDICATE SFC HEATING
WILL BE ENOUGH TO REMOVE MUCH OF THE CINH ASSOCIATED WITH
INSTABILITY AXIS THAT DEVELOPS ACROSS COLORADO. NOT REALLY CONFIDENT
IN PRECIP CHANCES OR COVERAGE...BUT THINK CURRENT ISOLATED CHANCES
IN THIS AREA LOOK REASONABLE ATTM.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS
THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT
THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND
A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND
IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG
UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE
ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE
AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS
MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE
EXPECTED PATTERN PRETTY WELL.
THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST
AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL
MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH
DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED
AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE
WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH
POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE
RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 539 AM MDT WED JUL 25 2012
ISOLATED MORNING THUNDERSTORMS WILL CONTINUE THROUGH AT LEAST 15Z
BEFORE MORE ORGANIZED THUNDERSTORMS DEVELOP AFTER 19Z IMPACTING
BOTH TERMINALS BEFORE ENDING EARLY THIS EVENING. SFC RIDGE WILL
BUILD OVER THE AREA OVERNIGHT WITH LIGHT AND VARIABLE WINDS
BRINGING THE POTENTIAL FOR PATCHY MORNING FOG...ESPECIALLY AROUND MCK.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...JRM
LONG TERM...JRM/PMM
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
508 AM MDT WED JUL 25 2012
.UPDATE...
ISSUED AT 457 AM MDT WED JUL 25 2012
ELEVATED THUNDERSTORMS HAVE DEVELOPED FARTHER TO THE EAST THAN
PREVIOUSLY EXPECTED...BEING DRIVEN BY ELEVATED FRONTAL ZONE AROUND
H8 AND POCKET OF WEAKLY CAPPED INSTABILITY IN BTWN H75 AND H65.
WHILE PRECIP COVERAGE HAS BEEN SPOTTY...MCK MEASURED A QUICK 0.2
OF RAIN IN ABOUT 15 MINUTES AS STORM PASSED. RAP INDICATES AREA OF
ELEVATED INSTABILITY SHIFTS TO THE NORTH AND DIMINISHES DURING
THE MORNING HOURS...BUT THINK A STORM OR TWO MAY CONTINUE TO
DEVELOP ALONG ELEVATED FRONT THIS MORNING AS SATELLITE INDICATING
LINEAR BAND OF COOLING CLOUD TOPS DEVELOPING FROM GOODLAND TO
NORTON. AM A LITTLE CONCERNED ABOUT ANOTHER POCKET OF ELEVATED
INSTABILITY ASSOCIATED WITH WEAK SHORT WAVE TROUGH THAT HAS BEEN
DRIFTING TO THE NORTH AND WOULD NOT BE OUT OF THE QUESTION TO SEE
A CELL OR TWO ALONG SOUTHERN FRINGE OF CWA AS FRONT INTERACTS WITH
THIS AREA. NOT REALLY SEEING ANY SIGNS OF THIS ON SATELLITE RIGHT
NOW AND WOULD LIKE TO SEE SOME CONFIRMATION WITH MORNING SOUNDINGS
BEFORE CHANGING FORECAST GREATLY. ASIDE FROM EARLY MORNING
CONVECTION...REST OF FORECAST STILL ON TRACK
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
03Z WATER VAPOR IMAGERY INDICATED LARGE AREA OF SUBSIDENCE/DRYING
THAT WAS OVER THE AREA THE PAST FEW DAYS HAD SHIFTED TO THE
NORTHEAST...WITH SUBTLE SHORT WAVE TROUGH MOVING ACROSS SOUTHERN
KANSAS WITH STRONG SHORT WAVE TROUGH MOVING ACROSS THE US/CANADIAN
BORDER. 00Z RAOBS SHOWED LITTLE CHANGE IN THERMAL PROFILES ACROSS
THE AREA WITH LARGEST CHANGES NOTED AT DDC WHERE TEMPS BELOW H7 HAS
WARMED AROUND 2C AND TEMPS BTWN H7 AND H5 HAD COOLED AROUND 2C.
PRIMARY FORECAST CONCERN WILL BE PRECIPITATION CHANCES TODAY AND
TONIGHT...FOLLOWED BY TEMPS THROUGH THE START OF THE WEEKEND.
TODAY...COLD FRONT IS CURRENTLY ADVANCING ACROSS THE CWA AND WILL
CONTINUE TO ADVANCE TO THE SOUTH BEFORE STALLING ACROSS SOUTHERN
PORTION OF THE CWA LATE THIS MORNING. ALREADY SEEING A FEW SHOWERS
AND THUNDERSTORMS POP UP BEHIND THE FRONT...ALTHOUGH PRECIP AMOUNTS
LOOK TOP BE VERY SPOTTY AS UPDRAFTS REMAIN WEAK AND SHORT LIVED.
POCKET OF LOW CINH AND WEAK INSTABILITY LOCATED AROUND H7 AND AREA
OF FRONTOGENESIS LINE UP WITH CURRENT ACTIVITY PRETTY WELL AND
GENERAL TRENDS WITH THESE FIELDS SUGGEST ACTIVITY SHOULD REMAIN
CONFINED TO THE NORTHWESTERN CWA DURING THE MORNING HOURS. LARGE
SCALE FORCING FOR ASCENT BEGINS TO INCREASE AS SHORT WAVE TROUGH
APPROACHES NEB PANHANDLE AND DRIFTS TO THE SOUTHEAST. INITIALLY
THOUGHT THAT PRECIPITATION WOULD STRUGGLE TO DEVELOP CLOSER TO
STRONGER UPPER LEVEL FORCING AND INSTEAD FAVOR FRONTAL ZONE TO THE
SOUTH BUT SEEING AS LIMITED INSTABILITY ALREADY BEING
REALIZED...THINK COVERAGE WILL IMPROVES AS FORCING
INCREASES...BEFORE SFC FRONT BECOMES PRIMARY FOCUS FOR STORMS LATE
IN THE AFTERNOON.
TONIGHT...BIG QUESTION FOR THE OVERNIGHT PERIOD WILL BE HOW LONG
PRECIPITATION LINGERS ACROSS THE AREA. WHILE PERIOD OF LARGE SCALE
FORCING FOR ASCENT AND MID LEVEL FRONTOGENESIS ARE IN PLACE ACROSS
MUCH OF THE AREA AT 00Z...THESE FIELDS DIMINISH CONSIDERABLY DURING
THE EVENING HOURS AND THINK BULK OF PRECIPITATION WILL BE TIED TO
FRONTAL ZONE WHICH WILL BE MOVING QUICKLY OUT OF THE CWA. WHILE
INITIAL THOUGHTS ARE MUCH OF THE CWA WILL BE DONE WITH PRECIPITATION
AROUND 00Z...HAVE SOME CONCERNS THAT SOUNDINGS INDICATE SOME
POTENTIAL DESTABILIZATION ACROSS EASTERN COLORADO AFTER FRONT
PASSES. NOT SURE I CAN PUT REALLY GREAT CONFIDENCE INTO THIS
SOLUTION...BUT WITH LATEST GEFS AS WELL AS LOCAL NEIGHBORHOOD
PRECIPITATION GUIDANCE THINK LINGERING HIGHER POPS INTO AT LEAST 2Z
IS WARRANTED.
TOMORROW...NORTHWESTERLY FLOW ALOFT WILL BE IN PLACE ACROSS THE AREA
AS H5 RIDGE AMPLIFIES OVER THE ROCKIES WITH SFC HIGH BRINGING FAIRLY
LIGHT AND VARIABLE WINDS ACROSS THE CWA. WHILE THERE IS NOT IN THE
WAY OF LARGE SCALE FORCING...GENERAL MODELS INDICATE SFC HEATING
WILL BE ENOUGH TO REMOVE MUCH OF THE CINH ASSOCIATED WITH
INSTABILITY AXIS THAT DEVELOPS ACROSS COLORADO. NOT REALLY CONFIDENT
IN PRECIP CHANCES OR COVERAGE...BUT THINK CURRENT ISOLATED CHANCES
IN THIS AREA LOOK REASONABLE ATTM.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 AM MDT WED JUL 25 2012
THURSDAY NIGHT-FRIDAY NIGHT...DESPITE SLOWLY AMPLIFYING RIDGE ACROSS
THE AREA...THERE WILL BE PERIODS OF LARGE SCALE FORCING FOR ASCENT
THROUGH THE PERIOD AS RIDGE AXIS REMAINS TO THE WEST OF THE AREA AND
A FEW SMALL SHORT WAVE TROUGHS MOVE OVER THE TOP OF THE RIDGE AND
IMPACT THE AREA. SOME DIFFERENCES EXIST WITH RESPECT TO HOW STRONG
UPCOMING RIDGE WILL BE WHICH WILL STRONGLY IMPACT HOW MUCH INFLUENCE
ANY OF THESE SMALL SCALE TROUGHS WILL HAVE. WHILE NAM AND SREF QUITE
AGGRESSIVE DEVELOPING CONVECTION ACROSS NORTHERN CWA...GFS AND GEFS
MUCH DRIER. FOR NOW...THINK GEFS SOLUTION OF 15-20 POPS REFLECTS THE
EXPECTED PATTERN PRETTY WELL.
THE NEXT UPPER LEVEL RIDGE WILL BUILD OVER THE INTERMOUNTAIN WEST
AND OVER THE ROCKIES BY THIS WEEKEND. A FEW SHORTWAVE TROUGHS WILL
MOVE THROUGH THE FLOW DURING THE PERIOD AND WITH SURFACE TROUGH
DEEPENING ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED
AFTERNOON THUNDERSTORMS MOST DAYS. BY EARLY NEXT WEEK...THE RIDGE
WILL MOVE EASTWARD INTO THE PLAINS WITH THE MAIN CENTER OF THE HIGH
POSITIONED ACROSS THE SOUTHERN PLAINS REGION MONDAY BEFORE
RETROGRADING BACK INTO THE SOUTHERN ROCKY MOUNTAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1040 PM MDT TUE JUL 24 2012
VFR CONDITIONS ARE FORECAST FOR THE 6Z TAFS. LATEST RADAR SHOWS
THE COLD FRONT MOVING INTO YUMA COUNTY. IF THE FRONT CONTINUES WITH
ITS CURRENT SPEED IT WILL ARRIVE AT KGLD AND KMCK AROUND 17 OR
18Z. AHEAD OF THE FRONT WINDS WILL BE LIGHT. ONCE THE FRONT MOVES
THROUGH WINDS WILL TURN TO THE NORTH AND BECOME GUSTY. DUE TO THE
DRY AIR AHEAD OF THE FRONT AND LACK OF INSTABILITY BEHIND THE
FRONT...MOST OF THE THUNDERSTORMS SHOULD BE TIED TO THE FRONT.
SOME THUNDERSTORMS COULD BECOME SEVERE DURING THE AFTERNOON. THE
STORMS WILL COME TO AN END DURING THE LATE AFTERNOON WITH THE
WINDS DECLINING DURING THE EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...JRM
LONG TERM...JRM/PMM
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
603 AM CDT WED JUL 25 2012
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 418 AM CDT WED JUL 25 2012
AN INTENSE UPPER LOW OVER THE SOUTHERN CANADIAN PRAIRIES CONTINUED
TO MOVE SLOWLY EAST DURING THE OVERNIGHT HOURS. THERE WERE TWO LOWS
EVIDENT AT 850MB IN THE 25.00Z ANALYSIS. THE NORTHERN LOW WAS WELL
INTO CANADA NEAR SASKATOON, SASKATCHEWAN. FARTHER SOUTH IN THE
CONUS...A LOW WAS CENTERED EAST OF THE BLACK HILLS OF SOUTH DAKOTA.
A FAIRLY INTENSE TEMPERATURE GRADIENT WAS NOTED ACROSS SOUTH DAKOTA
WITH +20C AT BISMARCK, ND AND +31C NOSING INTO SOUTH CENTRAL SD PER
THE RAP ANALYSIS. SEVERAL CLUSTERS OF THUNDERSTORMS DEVELOPED ACROSS
SOUTH DAKOTA ALONG THIS BAROCLINIC ZONE, WITH A LARGE MCS ROLLING
ACROSS NORTHERN MINNESOTA AS OF 08Z. ELSEWHERE...A SUBTLE BUT
IMPORTANT SHORTWAVE TROUGH COULD BE PICKED OUT IN THE RAP ANALYSIS
AND WATER VAPOR IMAGERY MOVING EAST THROUGH UTAH AND SOUTHWESTERN
WYOMING...MOVING INTO WESTERN/NORTHWESTERN COLORADO. A SURFACE COLD
FRONT AS OF 08Z EXTENDED FROM NORTH CENTRAL NEBRASKA TO NORTHEASTERN
COLORADO. SURFACE WINDS BEHIND THE FRONT IN EASTERN COLORADO AND
THE NEBRASKA PANHANDLE WERE NORTHWEST 20 TO 25 KNOTS WITH SOME GUSTS
IN SOME PLACES EXCEEDING 30 KNOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 418 AM CDT WED JUL 25 2012
THE MAIN CHALLENGE IN THE FORECAST PERTAINS TO THUNDERSTORM CHANCES,
STRENGTH, AND LOCATION OF THOSE BEST CHANCES LATER ON THIS AFTERNOON
AND TONIGHT AS THE COLD FRONT REACHES SOUTHWEST KANSAS. 850MB TEMPS
AHEAD OF THE FRONT UP TO +31C SUGGEST ANOTHER DAY OF HIGHS IN THE
103 TO 106F RANGE WITH THE NORTHERN FORECAST AREA SEEING THE HOTTEST
TEMPERATURES AGAIN...MUCH LIKE THE PAST FEW DAYS. IF THE STORMS HOLD
OFF LONG ENOUGH...HAYS COULD REACH 108F AGAIN LIKE YESTERDAY.
INITIAL THUNDERSTORMS SHOULD DEVELOP AS SURFACE TEMPERATURES
APPROACH CONVECTIVE TEMPERATURE ALONG AN AXIS FROM ROUGHLY ELKHART
TO SYRACUSE TO WAKEENEY-GOVE AREAS. OTHER STORMS MAY FORM FARTHER
EAST TIED TO A WEAK MID LEVEL VORTICITY ANOMALY THAT WILL MOVE
SLOWLY EAST ACROSS SOUTHWEST KANSAS DURING THE AFTERNOON. THESE
STORMS SHOULD BE ALL THAT STRONG SINCE LOW LEVEL CONVERGENCE WILL BE
ESSENTIALLY NON-EXISTENT (REMAINING FARTHER NORTH).
THE MOST ORGANIZED THUNDERSTORMS WILL DEVELOP IN THE 22-00Z TIME
FRAME FROM ROUGHLY LAKIN TO SCOTT CITY TO WAKEENEY. THESE STORMS
WILL ADVANCE SLOWLY SOUTHEAST THROUGH THE EVENING HOURS WITH
SUBSEQUENT DEVELOPMENT OF STORMS FORMING ON VARIOUS COLD POOL
INTERACTIONS WHICH ARE IMPOSSIBLE TO PREDICT. IT IS UNCLEAR WHETHER
A SMALL MCS MAY DEVELOP AND THRIVE PAST THE ~04Z TIME FRAME...AS LOW
LEVEL MOISTURE, WHILE ADEQUATE IN THE UPPER 50S TO LOWER 60S...WILL
NOT BE NEAR WHAT THE GFS MODEL IS SUGGESTING (A CHRONIC PROBLEM WITH
THIS MODEL ALL SEASON). THE SHORTWAVE TROUGH MENTIONED IN THE
SYNOPSIS SECTION ENTERING COLORADO WILL AID IN SOME INCREASED DEEP
UPWARD VERTICAL MOTION LATE TONIGHT...BUT BY THE TIME THAT REACHES
WESTERN KANSAS...MUCH OF THE CONVECTIVE ACTIVITY WILL LIKELY HAVE
SHIFTED EAST INTO CENTRAL KANSAS.
AS FAR AS THE POP FORECAST GOES...WILL BE INCREASING THE POPS TO
50-60 PERCENT NORTH OF A GARDEN CITY TO LARNED LINE TO INTERSTATE 70
CORRIDOR. AS FAR AS THE SEVERE WEATHER POTENTIAL GOES...THERE IS
DEFINITELY A CHANCE AT AT LEAST SOME ISOLATED SEVERE WIND REPORTS
GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS. STRONG UPDRAFTS
ARE QUITE LIKELY GIVEN THE STRONG LOW LEVEL CONVERGENCE WITH THE
SLOW MOVING FRONT. THIS WILL LEAD TO INTENSE DOWNDRAFTS AND EVEN A
FEW SEVERE MICROBURSTS. THE HAIL THREAT IS RATHER LOW CONSIDERING
THE POOR VERTICAL WIND SHEAR AND OVERALL WARM MID LEVEL TEMPERATURES
AS WELL AS HIGH MELTING AND -20C LEVELS. WILL BE DECREASING POPS
ACROSS MUCH OF THE FORECAST AREA DURING THE 06-12Z TIME FRAME WITH
COLD ADVECTION TAKING OVER IN THE LOW LEVELS AS THE SYNOPTIC FRONT
CONTINUES SOUTHEAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 234 AM CDT WED JUL 25 2012
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
DEVELOPING ACROSS THE FAR INTERMOUNTAIN WEST TODAY AND DRIFTING
SLOWLY EAST ACROSS THE ROCKIES TO BEGIN THE PERIOD THURSDAY. IT
WILL MOVE FURTHER INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND
QUICKLY BRINGING A GENERALLY DRIER WEATHER PATTERN BACK TO
WESTERN KANSAS DURING MUCH OF THE PERIOD. AIDING THIS DRIER
PATTERN WILL BE A FAIRLY WEAK FLOW ALOFT ASSOCIATED WITH THE
UPPER LEVEL RIDGING.
TEMPERATURES ARE EXPECTED TO BE MORE SEASONAL THURSDAY IN WAKE OF
A COLD FRONTAL PASSAGE LATE WEDNESDAY. A NORTH TO NORTHEAST LOW
LEVEL FLOW WILL PREVAIL ACROSS WESTERN KANSAS THURSDAY HELPING TO
LOWER H85 TEMPERATURES EVER SO SLIGHTLY WITH VALUES GENERALLY
RANGING FROM THE MID 20S(C) ACROSS CENTRAL KANSAS TO THE UPPER
20S(C) IN EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS ONLY UP INTO
THE 90S(F) THURSDAY AFTERNOON. A GRADUAL WARMING TREND IS STILL
EXPECTED INTO THE WEEKEND AS THE AFOREMENTIONED UPPER LEVEL
RIDGING APPROACHES FROM THE INTERMOUNTAIN WEST BY THURSDAY AND
BEGINS TO PUSH EAST INTO THE WESTERN HIGH PLAINS THROUGH THE
WEEKEND. SHOULD SEE HIGHS CLIMBING UP NEAR TO JUST ABOVE 100F BY
THE CLOSE OF THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 600 AM CDT WED JUL 25 2012
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE ALONG
AND AHEAD OF A COLD FRONT THAT WILL PUSH SLOWLY SOUTHEAST ACROSS
SOUTHWEST KANSAS THIS AFTERNOON AND EVENING AND INTO SOUTH CENTRAL
KANSAS TONIGHT. WILL INTRODUCE VCTS AND CB TO ALL TAF SITES THIS
AFTERNOON AS A RESULT. ANY DEVELOPING STORMS WILL HAVE THE
POTENTIAL OF BECOMING FAIRLY STRONG WITH GUSTY AND POSSIBLY
DAMAGING OUTFLOW WINDS THE PRIMARY THREAT. OTHERWISE, VFR
CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES THROUGH LATE
THIS EVENING. AS FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE IN
EXTREME EASTERN COLORADO WILL BEGIN TO PUSH EAST INTO FAR WESTERN
KANSAS THROUGH EARLY THIS AFTERNOON. AS A RESULT, SOUTHERLY WINDS
OF 10 TO 15KT EARLY THIS MORNING WILL BECOME 15 TO 25KT ACROSS
CENTRAL AND PORTIONS OF SOUTHWEST KANSAS BY EARLY AFTERNOON. A
COLD FRONT IS THEN PROJECTED TO PUSH SLOWLY SOUTHEAST INTO WESTERN
KANSAS MID TO LATE AFTERNOON MOVING ACROSS SOUTHWEST THIS
EVENING...AND SOUTH CENTRAL KANSAS BY EARLY THURSDAY MORNING.
WINDS ARE FORECAST TO BECOME NORTHERLY 10 TO 20KT BEHIND THE FRONT
AS IT MOVES THROUGH THIS EVENING AND OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 104 69 96 67 / 30 40 10 0
GCK 103 67 95 66 / 40 50 10 0
EHA 102 67 93 67 / 30 30 10 0
LBL 104 68 95 67 / 30 30 10 0
HYS 106 68 95 67 / 30 60 10 0
P28 103 74 98 71 / 10 40 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
420 AM CDT WED JUL 25 2012
...UPDATED SYNOPSIS AND SHORT TERM SECTIONS...
.SYNOPSIS...
ISSUED AT 418 AM CDT WED JUL 25 2012
AN INTENSE UPPER LOW OVER THE SOUTHERN CANADIAN PRAIRIES CONTINUED
TO MOVE SLOWLY EAST DURING THE OVERNIGHT HOURS. THERE WERE TWO LOWS
EVIDENT AT 850MB IN THE 25.00Z ANALYSIS. THE NORTHERN LOW WAS WELL
INTO CANADA NEAR SASKATOON, SASKATCHEWAN. FARTHER SOUTH IN THE
CONUS...A LOW WAS CENTERED EAST OF THE BLACK HILLS OF SOUTH DAKOTA.
A FAIRLY INTENSE TEMPERATURE GRADIENT WAS NOTED ACROSS SOUTH DAKOTA
WITH +20C AT BISMARCK, ND AND +31C NOSING INTO SOUTH CENTRAL SD PER
THE RAP ANALYSIS. SEVERAL CLUSTERS OF THUNDERSTORMS DEVELOPED ACROSS
SOUTH DAKOTA ALONG THIS BAROCLINIC ZONE, WITH A LARGE MCS ROLLING
ACROSS NORTHERN MINNESOTA AS OF 08Z. ELSEWHERE...A SUBTLE BUT
IMPORTANT SHORTWAVE TROUGH COULD BE PICKED OUT IN THE RAP ANALYSIS
AND WATER VAPOR IMAGERY MOVING EAST THROUGH UTAH AND SOUTHWESTERN
WYOMING...MOVING INTO WESTERN/NORTHWESTERN COLORADO. A SURFACE COLD
FRONT AS OF 08Z EXTENDED FROM NORTH CENTRAL NEBRASKA TO NORTHEASTERN
COLORADO. SURFACE WINDS BEHIND THE FRONT IN EASTERN COLORADO AND
THE NEBRASKA PANHANDLE WERE NORTHWEST 20 TO 25 KNOTS WITH SOME GUSTS
IN SOME PLACES EXCEEDING 30 KNOTS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 418 AM CDT WED JUL 25 2012
THE MAIN CHALLENGE IN THE FORECAST PERTAINS TO THUNDERSTORM CHANCES,
STRENGTH, AND LOCATION OF THOSE BEST CHANCES LATER ON THIS AFTERNOON
AND TONIGHT AS THE COLD FRONT REACHES SOUTHWEST KANSAS. 850MB TEMPS
AHEAD OF THE FRONT UP TO +31C SUGGEST ANOTHER DAY OF HIGHS IN THE
103 TO 106F RANGE WITH THE NORTHERN FORECAST AREA SEEING THE HOTTEST
TEMPERATURES AGAIN...MUCH LIKE THE PAST FEW DAYS. IF THE STORMS HOLD
OFF LONG ENOUGH...HAYS COULD REACH 108F AGAIN LIKE YESTERDAY.
INITIAL THUNDERSTORMS SHOULD DEVELOP AS SURFACE TEMPERATURES
APPROACH CONVECTIVE TEMPERATURE ALONG AN AXIS FROM ROUGHLY ELKHART
TO SYRACUSE TO WAKEENEY-GOVE AREAS. OTHER STORMS MAY FORM FARTHER
EAST TIED TO A WEAK MID LEVEL VORTICITY ANOMALY THAT WILL MOVE
SLOWLY EAST ACROSS SOUTHWEST KANSAS DURING THE AFTERNOON. THESE
STORMS SHOULD BE ALL THAT STRONG SINCE LOW LEVEL CONVERGENCE WILL BE
ESSENTIALLY NON-EXISTENT (REMAINING FARTHER NORTH).
THE MOST ORGANIZED THUNDERSTORMS WILL DEVELOP IN THE 22-00Z TIME
FRAME FROM ROUGHLY LAKIN TO SCOTT CITY TO WAKEENEY. THESE STORMS
WILL ADVANCE SLOWLY SOUTHEAST THROUGH THE EVENING HOURS WITH
SUBSEQUENT DEVELOPMENT OF STORMS FORMING ON VARIOUS COLD POOL
INTERACTIONS WHICH ARE IMPOSSIBLE TO PREDICT. IT IS UNCLEAR WHETHER
A SMALL MCS MAY DEVELOP AND THRIVE PAST THE ~04Z TIME FRAME...AS LOW
LEVEL MOISTURE, WHILE ADEQUATE IN THE UPPER 50S TO LOWER 60S...WILL
NOT BE NEAR WHAT THE GFS MODEL IS SUGGESTING (A CHRONIC PROBLEM WITH
THIS MODEL ALL SEASON). THE SHORTWAVE TROUGH MENTIONED IN THE
SYNOPSIS SECTION ENTERING COLORADO WILL AID IN SOME INCREASED DEEP
UPWARD VERTICAL MOTION LATE TONIGHT...BUT BY THE TIME THAT REACHES
WESTERN KANSAS...MUCH OF THE CONVECTIVE ACTIVITY WILL LIKELY HAVE
SHIFTED EAST INTO CENTRAL KANSAS.
AS FAR AS THE POP FORECAST GOES...WILL BE INCREASING THE POPS TO
50-60 PERCENT NORTH OF A GARDEN CITY TO LARNED LINE TO INTERSTATE 70
CORRIDOR. AS FAR AS THE SEVERE WEATHER POTENTIAL GOES...THERE IS
DEFINITELY A CHANCE AT AT LEAST SOME ISOLATED SEVERE WIND REPORTS
GIVEN THE SIGNIFICANT TEMPERATURE-DEWPOINT SPREADS. STRONG UPDRAFTS
ARE QUITE LIKELY GIVEN THE STRONG LOW LEVEL CONVERGENCE WITH THE
SLOW MOVING FRONT. THIS WILL LEAD TO INTENSE DOWNDRAFTS AND EVEN A
FEW SEVERE MICROBURSTS. THE HAIL THREAT IS RATHER LOW CONSIDERING
THE POOR VERTICAL WIND SHEAR AND OVERALL WARM MID LEVEL TEMPERATURES
AS WELL AS HIGH MELTING AND -20C LEVELS. WILL BE DECREASING POPS
ACROSS MUCH OF THE FORECAST AREA DURING THE 06-12Z TIME FRAME WITH
COLD ADVECTION TAKING OVER IN THE LOW LEVELS AS THE SYNOPTIC FRONT
CONTINUES SOUTHEAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 234 AM CDT WED JUL 25 2012
MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL RIDGE OF HIGH PRESSURE
DEVELOPING ACROSS THE FAR INTERMOUNTAIN WEST TODAY AND DRIFTING
SLOWLY EAST ACROSS THE ROCKIES TO BEGIN THE PERIOD THURSDAY. IT
WILL MOVE FURTHER INTO THE WESTERN HIGH PLAINS THROUGH THE WEEKEND
QUICKLY BRINGING A GENERALLY DRIER WEATHER PATTERN BACK TO
WESTERN KANSAS DURING MUCH OF THE PERIOD. AIDING THIS DRIER
PATTERN WILL BE A FAIRLY WEAK FLOW ALOFT ASSOCIATED WITH THE
UPPER LEVEL RIDGING.
TEMPERATURES ARE EXPECTED TO BE MORE SEASONAL THURSDAY IN WAKE OF
A COLD FRONTAL PASSAGE LATE WEDNESDAY. A NORTH TO NORTHEAST LOW
LEVEL FLOW WILL PREVAIL ACROSS WESTERN KANSAS THURSDAY HELPING TO
LOWER H85 TEMPERATURES EVER SO SLIGHTLY WITH VALUES GENERALLY
RANGING FROM THE MID 20S(C) ACROSS CENTRAL KANSAS TO THE UPPER
20S(C) IN EXTREME SOUTHWEST KANSAS. LOOK FOR HIGHS ONLY UP INTO
THE 90S(F) THURSDAY AFTERNOON. A GRADUAL WARMING TREND IS STILL
EXPECTED INTO THE WEEKEND AS THE AFOREMENTIONED UPPER LEVEL
RIDGING APPROACHES FROM THE INTERMOUNTAIN WEST BY THURSDAY AND
BEGINS TO PUSH EAST INTO THE WESTERN HIGH PLAINS THROUGH THE
WEEKEND. SHOULD SEE HIGHS CLIMBING UP NEAR TO JUST ABOVE 100F BY
THE CLOSE OF THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1242 AM CDT WED JUL 25 2012
THE FIRST COLD FRONT IN QUITE AWHILE WILL BE MOVING THROUGH
SOUTHWESTERN KANSAS LATE TOMORROW AND TOMORROW NIGHT. THUNDERSTORMS
WILL DEVELOP ALONG THE FRONT DURING THE LATE AFTERNOON AND INTO THE
EVENING HOURS. WILL CARRY VICINITY THUNDER IN THE 06Z TAF AT ALL
TERMINALS (DDC, GCK, HYS) FROM ROUGHLY 23Z TO 03Z OR SO...ALTHOUGH
THUNDERSTORMS WILL PROBABLY NOT AFFECT TERMINALS DURING THE ENTIRE
TIME FRAME AS NOTED IN THE TAF. THERE IS SOME MICROBURST POTENTIAL
WITH THE STRONGEST STORMS DURING THIS TIME FRAME WITH SUDDEN AND
SIGNIFICANT WIND SHIFTS POSSIBLE...EVEN AWAY FROM THUNDERSTORMS AS
COLD POOLS SPREAD OUT AWAY FROM THE STORMS. EVENTUALLY ONCE THE
CONVECTIVE ACTIVITY CEASES LATER IN THE EVENING...A NORTHWEST WIND
WILL PREVAIL AROUND 12 TO 15 KNOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 104 69 96 67 / 30 40 10 0
GCK 103 67 95 66 / 40 50 10 0
EHA 102 67 93 67 / 30 30 10 0
LBL 104 68 95 67 / 30 30 10 0
HYS 106 68 95 67 / 30 60 10 0
P28 103 74 98 71 / 10 40 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...JJOHNSON
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS JACKSON KY
1042 PM EDT THU JUL 26 2012
.UPDATE...
ISSUED AT 1042 PM EDT THU JUL 26 2012
CONVECTION CONTINUES TO FIRE ALONG A MODEST LOW LEVEL JET OCCURRING
ACROSS KENTUCKY. THE SEVERE CONVECTION HAS BEEN GRADUALLY WINDING
DOWN NORTH OF I-64 OVERALL...ALTHOUGH A FEW CELLS CONTINUE TO GET
STRONG OCCASIONALLY. ALONG AND SOUTH OF THE MOUNTAIN PARKWAY...THE
AIR MASS HAS NOT BEEN TAPPED OUT YET...SO WILL HOLD ONTO THE WATCH.
SOME STORMS ARE TRAINING NORTH OF I-64 IN THE PAST HOUR...SO WILL
HAVE TO WATCH FOR THE POTENTIAL OF SOME MINOR FLOODING IN POOR
DRAINAGE AREAS. DEEPER CONVECTION IS ALSO FIRING UP ACROSS CENTRAL
KENTUCKY...AND THIS CONTINUES TO SLOWLY SAG SOUTH WITH TIME...WHILE
INDIVIDUAL CELLS AND CLUSTERS MOVE EAST. DO EXPECT A GRADUAL WEAKENING
TREND AS THEY HEAD TOWARDS I-75...SO LOCALLY HEAVY RAINFALL MAY BE
THE BIGGEST THREAT FROM THESE BY THE TIME THEY MAKE IT INTO THE AREA
AFTER MIDNIGHT.
UPDATE ISSUED AT 741 PM EDT THU JUL 26 2012
STRONG TO SEVERE CONVECTION HAS MADE IT INTO THE I-64 CORRIDOR...WITH
MORE TRAILING CONVECTION OFF TO WSW. SO FAR...THIS LINE HAS ONLY
SAGGED SOUTHEAST SLIGHTLY IN THE PAST HOUR...HOWEVER THIS MAY MAKE
BETTER PROGRESS IN THE NEXT FEW HOURS IF COLD POOLING CAN GET GOING.
HAVE UPDATED THE FORECAST TO INCLUDE CATEGORICAL POPS IN THE
BLUEGRASS...AND THEN BLENDED INTO THE EXISTING TIMING FOR NOW UNTIL
IT BECOMES MORE CLEAR IF THE STORMS MAKE MORE OF A SOUTHEAST SAG WITH
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM EDT THU JUL 26 2012
CHALLENGING FORECAST FOR THE SHORT TERM. BEST DYNAMICS AND FORCING REMAIN
TO THE NORTH OF OUR AREA AT THIS TIME...BUT WITH CONTINUED INSOLATION
FOR SEVERAL MORE HOURS AIR MASS OVER EAST KY WILL CONTINUE TO
DESTABILIZE. LATEST GOES SOUNDER SHOWS LIFTED INDICES FROM -3 TO -5
OVER AREA...AND PLENTY OF LOW LEVEL MOISTURE IS IN PLACE WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S.
HOWEVER THE WINDOW FOR SEVERE WEATHER IN EAST KY LOOKS VERY LIMITED
DUE TO TIMING OF WHEN CONVECTION SHOULD ENTER THE AREA. BEST ESTIMATE
AT THIS TIME IS FOR CONVECTION TO ENTER THE FAR NORTH AROUND 8 PM.
WITH BEST FORCING REMAINING NORTH OF THE AREA AND THE FACT THAT WE
WILL BE LOSING DAYTIME HEATING DO NOT EXPECT CONVECTION THAT ENTERS
OUR AREA TO MAINTAIN SEVERE CHARACTERISTICS...IF IT IS SEVERE TO
BEGIN WITH...VERY FAR SOUTH AND EAST INTO THE FORECAST AREA.
THERE IS ALSO A WIDE RANGE OF MODEL SOLUTIONS FOR THE NEAR
TERM AS TO TIMING AND EXTENT OF SHOWERS AND THUNDERSTORMS TONIGHT AND
AGAIN ON FRIDAY INTO FRIDAY EVENING. FOR THE VERY NEAR TERM HAD BEEN
FAVORING THE HRRR WHICH HAD BEEN VERY CONSISTENT WITH SEVERAL RUNS IN
A ROW SHOWING THE SHOWERS AND THUNDERSTORMS MOVING INTO THE FAR
NORTH PART OF OUR AREA AROUND 01Z. HOWEVER THE LATEST...15Z RUN IS
KEEPING MOST OF OUR AREA DRY THROUGH 06Z. FOR NOW HAVE GONE WITH A
BLEND OF NEIGHBORING FORECAST OFFICE TIMING...CURRENT RADAR
TRENDS...ANALYSIS AND MODEL BLENDS.
ALL CONVECTION TONIGHT WILL BE PRE FRONTAL...AND WITH THE FRONT YET
TO PUSH INTO OUR AREA ON FRIDAY...ADDITIONAL THUNDERSTORMS WILL BE
POSSIBLE YET AGAIN...AS UPPER SHORT WAVE TROF MOVES ACROSS THE LAKES
AND OH VALLEY. THE 12Z NAM IS THE MOST AGGRESSIVE WITH THIS
IDEA...AND SPC HAS PLACED OUR ENTIRE AREA IN A SLIGHT RISK FOR
FRIDAY. THERE IS CONSIDERABLE QUESTION AS TO HOW MUCH INSTABILITY
WILL BE PRESENT ON FRIDAY THOUGH. WILL CARRY THUNDERSTORM CHANCES ON
FRIDAY FOR ONGOING MORNING CONVECTION AND ALSO CHANCE FOR
REDEVELOPMENT IN THE AFTERNOON...AND WILL CARRY SLIGHT CHANCE TO
CHANCE INTO FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU JUL 26 2012
THE PERIOD WILL BEGIN WITH AN UPPER LEVEL SHORTWAVE TROUGH PUSHING
EAST OF THE AREA WITH RISING HEIGHTS ACROSS THE REGION ON SAT. UPPER
LEVEL RIDGING WILL GENERALLY DOMINATE THE WEEKEND WITH SFC HIGH
PRESSURE BUILDING INTO THE OHIO VALLEY BEFORE SHIFTING EAST AT THE
END OF WEEKEND. HOWEVER...BY EARLY NEXT WEEK THE RIDGE BECOME
ESTABLISHED A BIT FURTHER SOUTHWEST IN THE SOUTHERN PLAINS WITH THE
REGION ENDING UP IN NW FLOW ALOFT BETWEEN THIS RIDGE AND TROUGHING
OVER THE GREAT LAKES...NORTHEAST AND DOWN ALONG THE EASTERN
SEABOARD. THIS OVERALL PATTERN WILL REMAIN UNCHANGED TROUGH THE END
OF THE PERIOD.
THIS SCENARIO WILL LEAD TO A RATHER QUIET AND PLEASANT PATTERN OVER
THE WEEKEND AND YIELD MORE ACTIVE WEATHER WITH THE THREAT OF
CONVECTION. THIS CONVECTION SHOULD LARGELY HAVE A DIURNAL COMPONENT
TO IT...BUT MCS NOCTURNAL CONVECTION WILL ALSO BE POSSIBLE. TIMING OF
THE THE GREATEST THREAT OF NOCTURNAL CONVECTION IS LOW ATTM...ALTHOUGH
MODELS TO POINT TOWARD SOME OF THIS POSSIBLY OCCURRING ON MON NIGHT.
WE WENT WITH SLIGHT CHANCE POPS IN THE SW LATE ON SUN NIGHT WITH
CHANCE POPS WITH THE DIURNAL FLAVOR FROM THEN ON.
AS FOR TEMPS...MAX TEMPS SHOULD AVERAGE NEAR NORMAL THROUGH THE
PERIOD...WITH THE GREATEST DEPARTURE IN OVERNIGHT LOWS FROM TUE NIGHT
ON. MIN T ON SAT NIGHT...IN THE LOW TO MID 60S MAY BE THE LOWEST
OBSERVED SO FAR THIS MONTH IN VALLEY LOCATIONS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 741 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH MOST OF THE
EVENING...AS ONGOING CONVECTION ALONG THE I-64 CORRIDOR LOOKS TO STAY
NORTH FOR A WHILE. SOUTHWEST WINDS WILL CONTINUE TO GUST IN THE
BROADER VALLEYS TO BETWEEN 15 AND 20 KTS THIS EVENING...BEFORE
DIMINISHING. THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE
FORECAST AREA FROM NORTH TO SOUTH DURING THE OVERNIGHT
PERIOD...ALTHOUGH CONFIDENCE IS NOT VERY HIGH WITH HOW MUCH THEY WILL
HOLD TOGETHER. ASSUMING THUNDERSTORMS DO HOLD TOGETHER...EXPECT IFR
TO MVFR CONDITIONS IN FOG AND LOW CLOUDS TO PERSIST INTO THE DAY ON
FRIDAY...WITH SCATTERED THUNDERSTORMS POSSIBLE ONCE AGAIN DURING THE
AFTERNOON HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SBH
LONG TERM....JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
741 PM EDT THU JUL 26 2012
.UPDATE...
ISSUED AT 741 PM EDT THU JUL 26 2012
STRONG TO SEVERE CONVECTION HAS MADE IT INTO THE I-64 CORRIDOR...WITH
MORE TRAILING CONVECTION OFF TO WSW. SO FAR...THIS LINE HAS ONLY
SAGGED SOUTHEAST SLIGHTLY IN THE PAST HOUR...HOWEVER THIS MAY MAKE
BETTER PROGRESS IN THE NEXT FEW HOURS IF COLD POOLING CAN GET GOING.
HAVE UPDATED THE FORECAST TO INCLUDE CATEGORICAL POPS IN THE
BLUEGRASS...AND THEN BLENDED INTO THE EXISTING TIMING FOR NOW UNTIL
IT BECOMES MORE CLEAR IF THE STORMS MAKE MORE OF A SOUTHEAST SAG WITH
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM EDT THU JUL 26 2012
CHALLENGING FORECAST FOR THE SHORT TERM. BEST DYNAMICS AND FORCING REMAIN
TO THE NORTH OF OUR AREA AT THIS TIME...BUT WITH CONTINUED INSOLATION
FOR SEVERAL MORE HOURS AIR MASS OVER EAST KY WILL CONTINUE TO
DESTABILIZE. LATEST GOES SOUNDER SHOWS LIFTED INDICES FROM -3 TO -5
OVER AREA...AND PLENTY OF LOW LEVEL MOISTURE IS IN PLACE WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S.
HOWEVER THE WINDOW FOR SEVERE WEATHER IN EAST KY LOOKS VERY LIMITED
DUE TO TIMING OF WHEN CONVECTION SHOULD ENTER THE AREA. BEST ESTIMATE
AT THIS TIME IS FOR CONVECTION TO ENTER THE FAR NORTH AROUND 8 PM.
WITH BEST FORCING REMAINING NORTH OF THE AREA AND THE FACT THAT WE
WILL BE LOSING DAYTIME HEATING DO NOT EXPECT CONVECTION THAT ENTERS
OUR AREA TO MAINTAIN SEVERE CHARACTERISTICS...IF IT IS SEVERE TO
BEGIN WITH...VERY FAR SOUTH AND EAST INTO THE FORECAST AREA.
THERE IS ALSO A WIDE RANGE OF MODEL SOLUTIONS FOR THE NEAR
TERM AS TO TIMING AND EXTENT OF SHOWERS AND THUNDERSTORMS TONIGHT AND
AGAIN ON FRIDAY INTO FRIDAY EVENING. FOR THE VERY NEAR TERM HAD BEEN
FAVORING THE HRRR WHICH HAD BEEN VERY CONSISTENT WITH SEVERAL RUNS IN
A ROW SHOWING THE SHOWERS AND THUNDERSTORMS MOVING INTO THE FAR
NORTH PART OF OUR AREA AROUND 01Z. HOWEVER THE LATEST...15Z RUN IS
KEEPING MOST OF OUR AREA DRY THROUGH 06Z. FOR NOW HAVE GONE WITH A
BLEND OF NEIGHBORING FORECAST OFFICE TIMING...CURRENT RADAR
TRENDS...ANALYSIS AND MODEL BLENDS.
ALL CONVECTION TONIGHT WILL BE PRE FRONTAL...AND WITH THE FRONT YET
TO PUSH INTO OUR AREA ON FRIDAY...ADDITIONAL THUNDERSTORMS WILL BE
POSSIBLE YET AGAIN...AS UPPER SHORT WAVE TROF MOVES ACROSS THE LAKES
AND OH VALLEY. THE 12Z NAM IS THE MOST AGGRESSIVE WITH THIS
IDEA...AND SPC HAS PLACED OUR ENTIRE AREA IN A SLIGHT RISK FOR
FRIDAY. THERE IS CONSIDERABLE QUESTION AS TO HOW MUCH INSTABILITY
WILL BE PRESENT ON FRIDAY THOUGH. WILL CARRY THUNDERSTORM CHANCES ON
FRIDAY FOR ONGOING MORNING CONVECTION AND ALSO CHANCE FOR
REDEVELOPMENT IN THE AFTERNOON...AND WILL CARRY SLIGHT CHANCE TO
CHANCE INTO FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU JUL 26 2012
THE PERIOD WILL BEGIN WITH AN UPPER LEVEL SHORTWAVE TROUGH PUSHING
EAST OF THE AREA WITH RISING HEIGHTS ACROSS THE REGION ON SAT. UPPER
LEVEL RIDGING WILL GENERALLY DOMINATE THE WEEKEND WITH SFC HIGH
PRESSURE BUILDING INTO THE OHIO VALLEY BEFORE SHIFTING EAST AT THE
END OF WEEKEND. HOWEVER...BY EARLY NEXT WEEK THE RIDGE BECOME
ESTABLISHED A BIT FURTHER SOUTHWEST IN THE SOUTHERN PLAINS WITH THE
REGION ENDING UP IN NW FLOW ALOFT BETWEEN THIS RIDGE AND TROUGHING
OVER THE GREAT LAKES...NORTHEAST AND DOWN ALONG THE EASTERN
SEABOARD. THIS OVERALL PATTERN WILL REMAIN UNCHANGED TROUGH THE END
OF THE PERIOD.
THIS SCENARIO WILL LEAD TO A RATHER QUIET AND PLEASANT PATTERN OVER
THE WEEKEND AND YIELD MORE ACTIVE WEATHER WITH THE THREAT OF
CONVECTION. THIS CONVECTION SHOULD LARGELY HAVE A DIURNAL COMPONENT
TO IT...BUT MCS NOCTURNAL CONVECTION WILL ALSO BE POSSIBLE. TIMING OF
THE THE GREATEST THREAT OF NOCTURNAL CONVECTION IS LOW ATTM...ALTHOUGH
MODELS TO POINT TOWARD SOME OF THIS POSSIBLY OCCURRING ON MON NIGHT.
WE WENT WITH SLIGHT CHANCE POPS IN THE SW LATE ON SUN NIGHT WITH
CHANCE POPS WITH THE DIURNAL FLAVOR FROM THEN ON.
AS FOR TEMPS...MAX TEMPS SHOULD AVERAGE NEAR NORMAL THROUGH THE
PERIOD...WITH THE GREATEST DEPARTURE IN OVERNIGHT LOWS FROM TUE NIGHT
ON. MIN T ON SAT NIGHT...IN THE LOW TO MID 60S MAY BE THE LOWEST
OBSERVED SO FAR THIS MONTH IN VALLEY LOCATIONS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 741 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH MOST OF THE
EVENING...AS ONGOING CONVECTION ALONG THE I-64 CORRIDOR LOOKS TO STAY
NORTH FOR A WHILE. SOUTHWEST WINDS WILL CONTINUE TO GUST IN THE
BROADER VALLEYS TO BETWEEN 15 AND 20 KTS THIS EVENING...BEFORE
DIMINISHING. THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE
FORECAST AREA FROM NORTH TO SOUTH DURING THE OVERNIGHT
PERIOD...ALTHOUGH CONFIDENCE IS NOT VERY HIGH WITH HOW MUCH THEY WILL
HOLD TOGETHER. ASSUMING THUNDERSTORMS DO HOLD TOGETHER...EXPECT IFR
TO MVFR CONDITIONS IN FOG AND LOW CLOUDS TO PERSIST INTO THE DAY ON
FRIDAY...WITH SCATTERED THUNDERSTORMS POSSIBLE ONCE AGAIN DURING THE
AFTERNOON HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SBH
LONG TERM....JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
248 AM EDT WED JUL 25 2012
.UPDATE...
ISSUED AT 112 AM EDT WED JUL 25 2012
HAVE SENT A COUPLE OF GRID UPDATES ALREADY ON THIS OVERNIGHT SHIFT...
FOR THE PURPOSE OF ADDING AND RAISING POPS FOR THE OVERNIGHT PERIOD.
SHOWERS AND THUNDERSTORMS HAVE QUICKLY DEVELOPED SINCE ABOUT 11 PM.
THE 00Z NAM SEEMS TO HAVE THE BEST HANDLE ON THE SITUATION...ALTHOUGH
IT APPEARS TO BE SLIGHTLY TOO FAR WEST WITH ITS AXIS OF HEAVIEST
PRECIP. WITH TRAINING THAT IS TAKING PLACE...HAVE SOME CONCERNS ABOUT
EXCESSIVE RAINFALL...ESPECIALLY SINCE IT IS OCCURRING IN AREAS WHICH
ALREADY HAD SUBSTANTIAL RAIN DURING THE DAY ON TUESDAY.
UPDATE ISSUED AT 950 PM EDT TUE JUL 24 2012
UPDATED THE FORECAST TO DROP THE SOUTHERN WATCH BOX AND EFFECTIVELY
REMOVE POPS FOR MOST OF THE NIGHT DOWN THERE. OTHERWISE...ADJUSTED
THE SKY COVER...TEMPS...AND DEW POINTS FOR CURRENT OBS AND TRENDS.
THE ONLY FLY IN THE OINTMENT FOR A QUIET REST OF THE NIGHT WILL BE
THE SEVERE THUNDERSTORM HEADING EAST...JUST NORTH OF INTERSTATE
64...ACROSS CENTRAL KENTUCKY. SHOULD THIS...AND ANY OF ITS TRAILING
CONVECTION TO THE WEST...HOLD TOGETHER...DESPITE LOWER INSTABILITY
AND A MORE WORKED OVER ENVIRONMENT HERE IN THE EAST...IT COULD MAKE
IT INTO THE CWA AROUND MIDNIGHT. FOR NOW HAVE PAINTED IT AS
DISSIPATING ON OUR FRINGES...BUT IT HAS BEEN GOING STRONG FOR OVER AN
HOUR NOW. WILL RE-EXAMINE IN AN HOUR OR SO...SHOULD IT STILL BE
INTACT. UPDATES HAVE BEEN ISSUED TO THE ZONES...NDFD GRIDS...AND
WEB.
UPDATE ISSUED AT 815 PM EDT TUE JUL 24 2012
UPDATED THE GRIDS TO REFLECT THE DIMINISHING THREAT OF SEVERE WEATHER
OR ANY FURTHER CONVECTION IN OUR FAR SOUTHERN COUNTIES. HOWEVER...
WILL HOLD OFF ON DROPPING THE BOX FOR ANOTHER HALF HOUR OR SO JUST TO
BE SURE THAT SOME BOUNDARY FROM THE WEST DOESN/T KICK OFF ANY STORMS
ALONG OUR BORDER REGION. THE BULK OF OUR AREA HAS NOW BEEN WORKED
OVER AND INSTABILITY IS FALLING SO THE ONLY THREAT ARE REMAINS IN THE
FAR SOUTHWEST. HOWEVER...WOULD NOT RULE OUT SOME REDEVELOPMENT ALONG
THE STALLED BOUNDARY LATER TONIGHT OR EVEN A BATCH OF CONVECTION
DROPPING DOWN FROM THE NORTH TOWARDS DAWN. HAVE KEPT THESE IDEAS
GOING FROM THE PREVIOUS SHIFT. IN ADDITION...PATCHES TO AREAS OF FOG
ARE ALSO ANTICIPATED THROUGH MUCH OF THE AREA BY DAWN...BECOMING
LOCALLY DENSE. THE FORECAST HAS THIS HANDLED WELL SO NOT ADJUSTMENTS
NEEDED HERE. DID ALSO TWEAK SKY COVER...TEMPS AND DEW POINTS FOR THE
CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD GRIDS AND
THE WEB.
UPDATE ISSUED AT 633 PM EDT TUE JUL 24 2012
WITH A MUGGY AND UNSTABLE AIR MASS STILL IN PLACE ACROSS THE SOUTHWEST
ZONES...SPC HAS ISSUED A NEW SEVERE THUNDERSTORM WATCH UNTIL 11 PM.
ONLY A FEW STORMS AFFECTING THE AREA PRESENTLY...BUT WE COULD STILL
SEE SOME NEW DEVELOPMENT THIS EVENING. MEANWHILE...QUIET CONDITIONS
ACROSS A GOOD CHUNK OF EASTERN KENTUCKY WILL LIKELY STAY THAT WAY
THROUGH MUCH OF TONIGHT. THUS...POPS HAVE BEEN REMOVED OR LOWERED
ACROSS THE BOARD. ALSO...WITH TEMPERATURES ALREADY ON THE COOL SIDE
AND RECENT RAINFALL...WE MAY SEE SOME PATCHY FOG OVERNIGHT. ZONE
UPDATE IS ALREADY OUT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 339 PM EDT TUE JUL 24 2012
IMMEDIATE SHORT TERM ISSUES REVOLVE AROUND THE ONGOING WATCH. WITH
MORE OF THE ACTIVITY SHIFTING SOUTHWARD...GOING TO CLEAR MORE
COUNTIES OUT OF EASTERN KENTUCKY OVER THE NEXT HOUR.
MEANWHILE...STILL WATCHING AN OUTFLOW BOUNDARY...FROM CENTRAL ESTILL
COUNTY...SOUTHEAST INTO SOUTHERN BREATHITT COUNTY. THIS BOUNDARY
COULD TRIGGER ADDITIONAL STORMS AS IT SINKS SOUTHWARD THIS EVENING.
THUS...THE WATCH WILL CONTINUE ACROSS OUR SOUTHWEST COUNTIES UNTIL
THIS BOUNDARY PUSHES ACROSS THIS AREA. THE HRRR CONTINUES TO SHOW NEW
DEVELOPMENT...BUT THUS FAR...HAVE NOT SEEN ANY DEVELOPMENT ALONG THIS
BOUNDARY.
AS THIS BOUNDARY AND COMPLEX OF STORMS EXITS TO THE SOUTH THIS
EVENING...THERE WILL LIKELY BE A TEMPORARY BREAK FROM THE CONVECTION.
HOWEVER...ANOTHER WEAK WAVE IS POISED TO DROP SOUTHWARD OVERNIGHT AND
COULD GENERATE MORE SHOWERS AND THUNDERSTORMS. WITH LITTLE ACTIVITY
UPSTREAM PRESENTLY...OPTING TO KEEP POPS ON THE LOWER SIDE UNTIL
BETTER CONFIDENCE CAN BE OBTAINED.
A NORTH/SOUTH BOUNDARY WILL THEN SET UP OVER FAR EASTERN KENTUCKY
THROUGH TOMORROW AFTERNOON AND EVENING. THIS WILL KEEP UNSETTLED
WEATHER IN THE FORECAST THROUGH WEDNESDAY EVENING AS DAYTIME
INSTABILITY WILL ONCE AGAIN FUEL STORM DEVELOPMENT...ESPECIALLY OVER
SOUTHEAST AND FAR EASTERN KENTUCKY. THE FURTHER WEST YOU GO AWAY FROM
THE BOUNDARY...THE MORE LIKELIHOOD TO MISS OUT ON ANY STORMS
TOMORROW. BASED ON THE WEAK STORM MOVEMENT TOMORROW AFTERNOON...WE
MAY HAVE TO WATCH FOR TRAINING STORMS AND FLASH FLOODING POTENTIAL.
PWS WILL STILL BE CLOSE TO 2 INCHES TOMORROW...SO CLEARLY GOING TO
HAVE TO KEEP AN EYE ON THE FLOODING POTENTIAL. WE MAY NEED A FLASH
FLOOD WATCH...BUT WILL LET THE MIDNIGHT SHIFT REEVALUATE.
THIS BOUNDARY WILL EVENTUALLY DEPART TO THE NORTHEAST TOMORROW
NIGHT...TAKING THE THREAT OF PRECIPITATION WITH IT AND PUTTING THE
AREA UNDER STRONGER INFLUENCE OF THE HIGH. MILD CONDITIONS WILL
CONTINUE WITH HIGHS ON WEDNESDAY WELL INTO THE 80S...AND LOWS TONIGHT
AND WEDNESDAY NIGHT IN THE LOWER 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 PM EDT TUE JUL 24 2012
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE
PATTERN. THURSDAY STARTS OUT WITH A UPPER LOW OVER MINNESOTA WITH A
TROUGH EXTENDING SOUTH ALONG THE I35 CORRIDOR. THE TROUGH WILL MOVE
TO THE EAST AND WILL PASS EASTERN KENTUCKY ON FRIDAY NIGHT/SATURDAY
MORNING TIME FRAME. THE TROUGH WILL FINALLY PUSH A LINGERING COLD
FRONT SOUTH AND EAST OF THE AREA ON FRIDAY. THIS WILL HELP TO BRING
SOME COOLER AND DRIER AIR INTO THE AREA. WITH THE MODELS IN SUCH
GOOD AGREEMENT...RELIED VERY HEAVILY ON THE MODEL BLEND FOR ALL
FIELDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 248 AM EDT WED JUL 25 2012
SHOWERS AND THUNDERSTORMS WERE ONGOING OVER THE NORTHERN AND EASTERN
PORTIONS OF THE FORECAST AREA AT THE START OF THE PERIOD...WITH
LOCALIZED IFR. THE AREA OF PRECIP WILL TRANSLATE TOWARD THE SE
OVERNIGHT...AND SHOULD MOSTLY BE OUT OF THE AREA BY 12Z.
HOWEVER...FOG WILL OCCUR...ESPECIALLY IN VALLEYS WHERE RAIN
FELL...AND WILL BRING LOCALIZED IFR UNTIL A LITTLE PAST SUNRISE. A
RELATIVE LULL IN PRECIP IS EXPECTED ON WEDNESDAY MORNING...WITH
MOSTLY VFR OUTSIDE OF EARLY MORNING FOG. HOWEVER...ADDITIONAL
THUNDERSTORMS ARE LIKELY TO DEVELOP IN THE AFTERNOON...ESPECIALLY
NEAR THE WV AND VA BORDERS. THESE SHOULD DIMINISH TOWARD SUNSET.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM....JJ
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
112 AM EDT WED JUL 25 2012
.UPDATE...
ISSUED AT 112 AM EDT WED JUL 25 2012
HAVE SENT A COUPLE OF GRID UPDATES ALREADY ON THIS OVERNIGHT SHIFT...
FOR THE PURPOSE OF ADDING AND RAISING POPS FOR THE OVERNIGHT PERIOD.
SHOWERS AND THUNDERSTORMS HAVE QUICKLY DEVELOPED SINCE ABOUT 11 PM.
THE 00Z NAM SEEMS TO HAVE THE BEST HANDLE ON THE SITUATION...ALTHOUGH
IT APPEARS TO BE SLIGHTLY TOO FAR WEST WITH ITS AXIS OF HEAVIEST
PRECIP. WITH TRAINING THAT IS TAKING PLACE...HAVE SOME CONCERNS ABOUT
EXCESSIVE RAINFALL...ESPECIALLY SINCE IT IS OCCURRING IN AREAS WHICH
ALREADY HAD SUBSTANTIAL RAIN DURING THE DAY ON TUESDAY.
UPDATE ISSUED AT 950 PM EDT TUE JUL 24 2012
UPDATED THE FORECAST TO DROP THE SOUTHERN WATCH BOX AND EFFECTIVELY
REMOVE POPS FOR MOST OF THE NIGHT DOWN THERE. OTHERWISE...ADJUSTED
THE SKY COVER...TEMPS...AND DEW POINTS FOR CURRENT OBS AND TRENDS.
THE ONLY FLY IN THE OINTMENT FOR A QUIET REST OF THE NIGHT WILL BE
THE SEVERE THUNDERSTORM HEADING EAST...JUST NORTH OF INTERSTATE
64...ACROSS CENTRAL KENTUCKY. SHOULD THIS...AND ANY OF ITS TRAILING
CONVECTION TO THE WEST...HOLD TOGETHER...DESPITE LOWER INSTABILITY
AND A MORE WORKED OVER ENVIRONMENT HERE IN THE EAST...IT COULD MAKE
IT INTO THE CWA AROUND MIDNIGHT. FOR NOW HAVE PAINTED IT AS
DISSIPATING ON OUR FRINGES...BUT IT HAS BEEN GOING STRONG FOR OVER AN
HOUR NOW. WILL RE-EXAMINE IN AN HOUR OR SO...SHOULD IT STILL BE
INTACT. UPDATES HAVE BEEN ISSUED TO THE ZONES...NDFD GRIDS...AND
WEB.
UPDATE ISSUED AT 815 PM EDT TUE JUL 24 2012
UPDATED THE GRIDS TO REFLECT THE DIMINISHING THREAT OF SEVERE WEATHER
OR ANY FURTHER CONVECTION IN OUR FAR SOUTHERN COUNTIES. HOWEVER...
WILL HOLD OFF ON DROPPING THE BOX FOR ANOTHER HALF HOUR OR SO JUST TO
BE SURE THAT SOME BOUNDARY FROM THE WEST DOESN/T KICK OFF ANY STORMS
ALONG OUR BORDER REGION. THE BULK OF OUR AREA HAS NOW BEEN WORKED
OVER AND INSTABILITY IS FALLING SO THE ONLY THREAT ARE REMAINS IN THE
FAR SOUTHWEST. HOWEVER...WOULD NOT RULE OUT SOME REDEVELOPMENT ALONG
THE STALLED BOUNDARY LATER TONIGHT OR EVEN A BATCH OF CONVECTION
DROPPING DOWN FROM THE NORTH TOWARDS DAWN. HAVE KEPT THESE IDEAS
GOING FROM THE PREVIOUS SHIFT. IN ADDITION...PATCHES TO AREAS OF FOG
ARE ALSO ANTICIPATED THROUGH MUCH OF THE AREA BY DAWN...BECOMING
LOCALLY DENSE. THE FORECAST HAS THIS HANDLED WELL SO NOT ADJUSTMENTS
NEEDED HERE. DID ALSO TWEAK SKY COVER...TEMPS AND DEW POINTS FOR THE
CURRENT OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE NDFD GRIDS AND
THE WEB.
UPDATE ISSUED AT 633 PM EDT TUE JUL 24 2012
WITH A MUGGY AND UNSTABLE AIR MASS STILL IN PLACE ACROSS THE SOUTHWEST
ZONES...SPC HAS ISSUED A NEW SEVERE THUNDERSTORM WATCH UNTIL 11 PM.
ONLY A FEW STORMS AFFECTING THE AREA PRESENTLY...BUT WE COULD STILL
SEE SOME NEW DEVELOPMENT THIS EVENING. MEANWHILE...QUIET CONDITIONS
ACROSS A GOOD CHUNK OF EASTERN KENTUCKY WILL LIKELY STAY THAT WAY
THROUGH MUCH OF TONIGHT. THUS...POPS HAVE BEEN REMOVED OR LOWERED
ACROSS THE BOARD. ALSO...WITH TEMPERATURES ALREADY ON THE COOL SIDE
AND RECENT RAINFALL...WE MAY SEE SOME PATCHY FOG OVERNIGHT. ZONE
UPDATE IS ALREADY OUT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 339 PM EDT TUE JUL 24 2012
IMMEDIATE SHORT TERM ISSUES REVOLVE AROUND THE ONGOING WATCH. WITH
MORE OF THE ACTIVITY SHIFTING SOUTHWARD...GOING TO CLEAR MORE
COUNTIES OUT OF EASTERN KENTUCKY OVER THE NEXT HOUR.
MEANWHILE...STILL WATCHING AN OUTFLOW BOUNDARY...FROM CENTRAL ESTILL
COUNTY...SOUTHEAST INTO SOUTHERN BREATHITT COUNTY. THIS BOUNDARY
COULD TRIGGER ADDITIONAL STORMS AS IT SINKS SOUTHWARD THIS EVENING.
THUS...THE WATCH WILL CONTINUE ACROSS OUR SOUTHWEST COUNTIES UNTIL
THIS BOUNDARY PUSHES ACROSS THIS AREA. THE HRRR CONTINUES TO SHOW NEW
DEVELOPMENT...BUT THUS FAR...HAVE NOT SEEN ANY DEVELOPMENT ALONG THIS
BOUNDARY.
AS THIS BOUNDARY AND COMPLEX OF STORMS EXITS TO THE SOUTH THIS
EVENING...THERE WILL LIKELY BE A TEMPORARY BREAK FROM THE CONVECTION.
HOWEVER...ANOTHER WEAK WAVE IS POISED TO DROP SOUTHWARD OVERNIGHT AND
COULD GENERATE MORE SHOWERS AND THUNDERSTORMS. WITH LITTLE ACTIVITY
UPSTREAM PRESENTLY...OPTING TO KEEP POPS ON THE LOWER SIDE UNTIL
BETTER CONFIDENCE CAN BE OBTAINED.
A NORTH/SOUTH BOUNDARY WILL THEN SET UP OVER FAR EASTERN KENTUCKY
THROUGH TOMORROW AFTERNOON AND EVENING. THIS WILL KEEP UNSETTLED
WEATHER IN THE FORECAST THROUGH WEDNESDAY EVENING AS DAYTIME
INSTABILITY WILL ONCE AGAIN FUEL STORM DEVELOPMENT...ESPECIALLY OVER
SOUTHEAST AND FAR EASTERN KENTUCKY. THE FURTHER WEST YOU GO AWAY FROM
THE BOUNDARY...THE MORE LIKELIHOOD TO MISS OUT ON ANY STORMS
TOMORROW. BASED ON THE WEAK STORM MOVEMENT TOMORROW AFTERNOON...WE
MAY HAVE TO WATCH FOR TRAINING STORMS AND FLASH FLOODING POTENTIAL.
PWS WILL STILL BE CLOSE TO 2 INCHES TOMORROW...SO CLEARLY GOING TO
HAVE TO KEEP AN EYE ON THE FLOODING POTENTIAL. WE MAY NEED A FLASH
FLOOD WATCH...BUT WILL LET THE MIDNIGHT SHIFT REEVALUATE.
THIS BOUNDARY WILL EVENTUALLY DEPART TO THE NORTHEAST TOMORROW
NIGHT...TAKING THE THREAT OF PRECIPITATION WITH IT AND PUTTING THE
AREA UNDER STRONGER INFLUENCE OF THE HIGH. MILD CONDITIONS WILL
CONTINUE WITH HIGHS ON WEDNESDAY WELL INTO THE 80S...AND LOWS TONIGHT
AND WEDNESDAY NIGHT IN THE LOWER 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 PM EDT TUE JUL 24 2012
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE
PATTERN. THURSDAY STARTS OUT WITH A UPPER LOW OVER MINNESOTA WITH A
TROUGH EXTENDING SOUTH ALONG THE I35 CORRIDOR. THE TROUGH WILL MOVE
TO THE EAST AND WILL PASS EASTERN KENTUCKY ON FRIDAY NIGHT/SATURDAY
MORNING TIME FRAME. THE TROUGH WILL FINALLY PUSH A LINGERING COLD
FRONT SOUTH AND EAST OF THE AREA ON FRIDAY. THIS WILL HELP TO BRING
SOME COOLER AND DRIER AIR INTO THE AREA. WITH THE MODELS IN SUCH
GOOD AGREEMENT...RELIED VERY HEAVILY ON THE MODEL BLEND FOR ALL
FIELDS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 815 PM EDT TUE JUL 24 2012
THE BULK OF THE CONVECTION HAS NOW FADED THROUGH THE AREA AND SHOULD
NOT BE A FACTOR IN THE TAFS THROUGH THE REMAINDER OF THE NIGHT.
HOWEVER...PATCHY DENSE FOG WILL BE A THREAT TONIGHT...ESPECIALLY IN
VALLEY LOCATIONS. LEFT FOG IN FOR THE TAF STATIONS...THOUGH IT WILL
LIKELY BE DEPENDENT ON WHICH AIRPORTS SAW PCPN AT OR NEAR THAT
PARTICULAR LOCATION. FOR WEDNESDAY...SCATTERED STORMS ARE AGAIN
ANTICIPATED TO DEVELOP BY MID AFTERNOON...MAINLY OVER FAR EASTERN
KENTUCKY. HAVE ADDED A VCTS FOR THIS AT JKL BUT LEFT LOZ AND SME
CLEAN. WINDS WILL BE LIGHT AND VARIABLE FOR THE MOST PART THROUGH THE
TAF PERIOD WITH SOME BREEZES UP TOWARD 5 AND 10 KTS POSSIBLE...
GENERALLY FROM THE SOUTHWEST...AROUND PEAK HEATING WEDNESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM....JJ
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
150 PM EDT WED JUL 25 2012
.SYNOPSIS...
ISSUED AT 345 AM EDT WED JUL 25 2012
A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME
HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW
PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD
FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS
TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN.
TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT
THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND
STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 1224 PM EDT WED JUL 25 2012
AREA OF SHOWERS AND STORMS HAVE TRIED TO MOVE INTO THE FORECAST
AREA THIS MORNING. FOR THE MOST PART THESE SHOWERS AND STORMS HAVE
DISSIPATED AS THEY MOVE INTO MUCH LESS INSTABILITY AND MOISTURE.
THE BETTER INSTABILITY DOES NOT MOVE INTO THE AREA UNTIL LATE THIS
AFTERNOON AND EVENING. THE NEXT FEW HOURS LOOK TO BE QUIET.
THE MAIN FOCUS FOR SHOWERS AND STORMS WILL BE FROM EARLY
EVENING...500PM-600PM THROUGH 100AM-200AM. ADDITIONAL STORMS ARE
EXPECTED OVERNIGHT. A COUPLE OF SCENARIOS ARE POSSIBLE FOR LATER
TODAY. THE FIRST SCENARIO IS THAT STORMS TO THE NORTH AND WEST
WILL MOVE INTO THE CWA FROM THE NORTH AND WEST AFTER DEVELOPING
THIS AFTERNOON. THE SECOND IS STORMS FIRE ALONG OUTFLOWS FROM
PRIOR CONVECTION VERY NEAR THE CWA OR OVER THE NORTHERN CWA THIS
AFTERNOON AND EVENING. EITHER WAY WE ARE EXPECTED STORMS TO PRESS
INTO AND MOVE THROUGH THE NORTHERN HALF OR SO OF THE FORECAST
AREA...ROUGHLY I96 NORTH...THIS EVENING.
DAMAGING WINDS LOOK TO BE THE MAIN THREAT AS 40-50 KNOTS OF WIND
WILL BE PRESENT BETWEEN 850MB AND 500MB/S. 35 TO 45 KNOTS OF 0-6KM
SHEAR IS PRESENT AS WELL WHICH WILL AID THUNDERSTORM UPDRAFTS AND
ALLOW FOR ROTATION. IF DISCRETE STORMS CAN DEVELOP AND MOVE ALONG
BOUNDARIES A TORNADO THREAT MAY DEVELOP AS WELL. DAMAGING WINDS
WILL AGAIN BE THE MAIN THREAT WITH A MUCH LOWER TORNADO AND HAIL
THREAT. FREEZING LEVELS SHOULD RISE TO AROUND 16000FT SO ONLY THE
STRONGEST OF UPDRAFTS WOULD BE CAPABLE OF SEVERE HAIL.
CANNOT RULE OUT SEVERE STORMS OVERNIGHT AS WELL AS INSTABILITY
WILL PERSIST GIVEN HIGH DEW POINTS AND THE 850MB LLJ WILL BE
OVERHEAD. MAIN TIME FRAME OF CONCERN THOUGH IS THIS EVENING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 345 AM EDT WED JUL 25 2012
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST
PERIOD AND TO ASSESS SEVERE WX POTENTIAL.
THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A
STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD
FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT
INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER
SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR
ORGANIZED SEVERE STORMS.
00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS
OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO
SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH
IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE
EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT
AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING
WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY
RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75
TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH
DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT.
THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE
THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE
EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND
40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE
PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR
PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE
DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS
EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE
WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED.
THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT
THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL
JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS
SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION
IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY.
THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE
HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION
LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM
FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS
NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS
PROPAGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR
EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING.
IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A
ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON
PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS
WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS
NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES
OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN.
EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR
CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN.
STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE
OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA
THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY
STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY
STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX
THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 AM EDT WED JUL 25 2012
THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS
THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE
AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND
COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS
SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH
THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE.
SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER
ARRIVES FROM THE NORTH.
MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA
OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES
OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED
TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE
IN THE LOWER TO MID 80S WITH LOWS AROUND 60.
SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR
MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE
BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN
DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY
SCATTERED COVERAGE EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 150 PM EDT WED JUL 25 2012
THE MAIN CONCERN TO AVIATION INTERESTS WITH THIS SET OF FCSTS IS
CONVECTIVE TRENDS...ESPECIALLY THIS EVENING. LATEST DATA IS STARTING
TO CONVERGE ON THE EXPECTED EVOLUTION OF STORMS FOR THIS EVENING. WE
ARE EXPECTING A BAND OF STORMS TO DEVELOP NORTHWEST OF THE AREA NEAR
KGRB AROUND 22-23Z TONIGHT. THESE ARE EXPECTED TO MOVE SE THROUGH
THE EVENING AND INTO THE EARLY OVERNIGHT HOURS. WE EXPECT THEM
AROUND KMKG AROUND 00-01Z AND THEN REACHING THE KJXN AREA AROUND
03-04Z. WIND GUSTS WILL BE THE MAIN THREAT ALONG WITH THE NORMAL
STORM HAZARDS.
SOME RESIDUAL SHOWERS WILL BE LIKELY BEHIND THE MAIN LINE OF STORMS.
MODELS ARE INDICATING SOME LOW CLOUDS MOVING IN BEHIND THE
FRONT...SIMILAR TO WHAT IS GOING ON CURRENTLY BEHIND THE FRONT.
ENOUGH WIND SHOULD BE IN PLACE TO KEEP FOG FROM BEING A BIG ISSUE.
WINDS WILL BECOME NW.
THE LOWER CLOUDS SHOULD LIFT INTO A VFR DECK DURING THE MID TO LATE
MORNING HOURS ON THU. THE SRN TERMINALS COULD SEE ANOTHER ROUND OF
SHOWERS/STORMS THU AFTERNOON...HOWEVER THE CONFIDENCE IN THAT RIGHT
NOW IS TOO LOW TO MENTION AT THIS TIME.
&&
.MARINE...
ISSUED AT 1224 PM EDT WED JUL 25 2012
WILL BE ISSUING A SMALL CRAFT ADVISORY AND A BEACH HAZARDS
STATEMENT FOR GRAND HAVEN NORTHWARD. THE TIME FRAME WILL BE FROM
THE CURRENT TIME THROUGH 400 AM TONIGHT WITH THE MAIN TIME FRAME
BEING THIS AFTERNOON AND EVENING. WAVES HAVE ALREADY BUILT TO NEAR
6.5 FEET AT THE LUDINGTON BUOY WITH SOUTHERLY WINDS IN THE 20-30
KNOT RANGE IN THE NORTHERN NEARSHORE WATERS BASED ON OBSERVATIONS.
WEBCAMS ON THE COAST ARE SHOWING WHITECAPS FROM MUSKEGON
NORTHWARD. THE WIND SHOULD TONE DOWN OVERNIGHT WITH THE THREAT
POTENTIALLY SHIFTING SOUTH OF GRAND HAVEN INTO THURSDAY MORNING. A
SCA AND BH.S MAY BE NEEDED FROM DAYBREAK INTO THE AFTERNOON ON
THURSDAY. THIS THREAT WILL BE REEVALUATED OVERNIGHT.
&&
.HYDROLOGY...
ISSUED AT 345 AM EDT WED JUL 25 2012
RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY
ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER
THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES
TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF
THE APPROACHING COLD FRONT TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ037-043-050.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT THURSDAY FOR LMZ847>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...NJJ
HYDROLOGY...LAURENS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
148 PM EDT WED JUL 25 2012
.UPDATE...
ISSUED AT 1232 PM EDT WED JUL 25 2012
HAVE MADE SOME ADJUSTMENTS TO THE SHORT TERM GRIDS TO BETTER LINE
UP WITH THE CURRENT TRENDS ON THE SHOWERS/THUNDERSTORMS MOVING
THROUGH CNTRL/ERN UPPER MI AND THEN BREAKS IN THE CLOUDS OVER THE
WEST HALF. THIS MORNING...MOST OF THE CWA RECEIVED OVER A HALF
INCH OF RAIN WITH SEVERAL LOCATIONS OVER THE WEST AND CENTRAL OVER
AN INCH. LARGEST TOTAL SO FAR WAS NEAR ROCKLAND...WHERE NEARLY 3
INCHES FELL.
BROAD SFC TROUGH OVER ERN MN AND POTENTIALLY TWO LOW PRESSURE
AREAS...ONE NEAR DULUTH AND THE OTHER IN SCNTRL MN. TO THE EAST OF
THIS BROAD LOW PRESSURE AREA...A WARM FRONT LOOKS TO BE SITUATED
EAST ACROSS CNTRL WI. THIS WARM FRONT IS THE MAIN ITEM OF
CONCERN...AS THERE HAVE BEEN DIFFERENCES IN THE SHORT TERM HIGH RES
MODEL RUNS ON HOW FAR N IT TRACKS. WITH SOME CLEARING IN WRN WI AND
EVEN INTO WRN UPPER MI...THINKING THAT REDEVELOPMENT WILL OCCUR IN
WRN WI ON THE DIFFERENTIAL HEATING AREA AND WITH RESIDUAL
CONVECTION COMING OUT OF CNTRL MN. THIS CO-LOCATED WHERE THE
INSTABILITY IS QUICKLY INCREASING TO 1500-2500 J/KG OF SBCAPE. IF
CONVECTION DEVELOPS THERE...SHOULD QUICKLY SEE STRONG/SEVERE STORMS
AS 0-6KM SHEAR VALUES APPROACH 50KTS. WITH THE EXPECTED STORM MOTION
A GENERAL ERLY DIRECTION...THINK THE BEST SHOT OF STRONG/SEVERE
STORMS WILL BE ALONG THE WI BORDER THROUGH THE AFTN AND TOWARDS
EARLY EVENING OVER THE SCNTRL. WITH THE CLEARING SEEN OVER PORTIONS
OF WRN UPPER MI...LINGERING MID LVL WAA...AND RIGHT REAR AREA OF
UPPER JET...COULD ALSO SEE SOME DEVELOPMENT FARTHER N THAN THE MAIN
AREA...SO WILL CONTINUE TO MENTION ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS OVER THE WEST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EDT WED JUL 25 2012
ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED
OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST
EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA
FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7
MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC
LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM
FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG
AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM
SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE
EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT
RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT
STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY
STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES
NEAR IWD WITHIN THE NEXT 2-3 HRS.
NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE
TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS
COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A
CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL
FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON
NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL
CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN
THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS
NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT.
LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL
AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR
WEST HALF AND SOON THERE AFTER IN THE EAST.
WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE
CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY
MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX
THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT
SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT
OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER
SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO
MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND
OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT
HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF
MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE
SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY
COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN
OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING.
LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN
WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW
COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN
THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT
SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL
AFTER DAYBREAK ON THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 439 AM EDT WED JUL 25 2012
BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER
NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING
STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT
NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE
FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS
FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT
CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL
PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS
BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR.
ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING
UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE
AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY
100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED
ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF
CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM
PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS
EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH
PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT
INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE
ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS
/BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN
BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN
2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND
SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW
RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING
THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM
LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT.
500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER
GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL
MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND
NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY
LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL
CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST
AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO
SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL
LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN
PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE
WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON
THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN
WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY
CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS
DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE
INFLUENCE.
500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE
THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES
ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES
RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE
THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK
SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG
RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND
RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING
INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF
NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE
AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH
MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 147 PM EDT WED JUL 25 2012
A BREAK BEHIND THE SHOWERS AND THUNDERSTORMS THIS MORNING HAS LED TO
HIGHER VSBYS/CIGS INTO THE VFR/MVFR RANGE. EXPECT THIS TO CONTINUE
OVER THE NEXT COUPLE OF HOURS UNTIL SHOWERS AND THUNDERSTORMS TRY TO
DEVELOP OVER NW WI AND POTENTIALLY AFFECT KIWD AND THEN KSAW. AFTER
THIS POTENTIAL...SFC LOW WILL SLIDE E FROM ECNTRL MN INTO ERN WI. AS
THIS OCCURS...EXPECT LLVL MOISTURE TO BE ON THE INCREASE AND AIDED
BY UPSLOPE FLOW. THIS SHOULD LEAD TO IFR OR LOWER CIGS FROM LATE
THIS EVENING INTO TOMORROW MORNING. BELIEVE THE BEST CHANCE OF
CIGS/VSBY NEARING AIRFIELD LANDING MINS WILL BE AT KCMX/KSAW...WHERE
THE UPSLOPE FLOW WITH THE BE MOST FAVORABLE. THE CIGS SHOULD LIFT
SOME HEADING THROUGH TOMORROW MORNING AS THE UPSLOPE FLOW WEAKENS
AND MIXING SLOWLY BRINGS THEM UP.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM EDT WED JUL 25 2012
LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE
EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND
STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER
GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN
MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT
WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR
EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW
MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE
LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20 KTS THROUGH THE
WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...JLA
LONG TERM...JMW
AVIATION...SRF
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EDT WED JUL 25 2012
.UPDATE...
ISSUED AT 1232 PM EDT WED JUL 25 2012
HAVE MADE SOME ADJUSTMENTS TO THE SHORT TERM GRIDS TO BETTER LINE
UP WITH THE CURRENT TRENDS ON THE SHOWERS/THUNDERSTORMS MOVING
THROUGH CNTRL/ERN UPPER MI AND THEN BREAKS IN THE CLOUDS OVER THE
WEST HALF. THIS MORNING...MOST OF THE CWA RECEIVED OVER A HALF
INCH OF RAIN WITH SEVERAL LOCATIONS OVER THE WEST AND CENTRAL OVER
AN INCH. LARGEST TOTAL SO FAR WAS NEAR ROCKLAND...WHERE NEARLY 3
INCHES FELL.
BROAD SFC TROUGH OVER ERN MN AND POTENTIALLY TWO LOW PRESSURE
AREAS...ONE NEAR DULUTH AND THE OTHER IN SCNTRL MN. TO THE EAST OF
THIS BROAD LOW PRESSURE AREA...A WARM FRONT LOOKS TO BE SITUATED
EAST ACROSS CNTRL WI. THIS WARM FRONT IS THE MAIN ITEM OF
CONCERN...AS THERE HAVE BEEN DIFFERENCES IN THE SHORT TERM HIGH RES
MODEL RUNS ON HOW FAR N IT TRACKS. WITH SOME CLEARING IN WRN WI AND
EVEN INTO WRN UPPER MI...THINKING THAT REDEVELOPMENT WILL OCCUR IN
WRN WI ON THE DIFFERENTIAL HEATING AREA AND WITH RESIDUAL
CONVECTION COMING OUT OF CNTRL MN. THIS CO-LOCATED WHERE THE
INSTABILITY IS QUICKLY INCREASING TO 1500-2500 J/KG OF SBCAPE. IF
CONVECTION DEVELOPS THERE...SHOULD QUICKLY SEE STRONG/SEVERE STORMS
AS 0-6KM SHEAR VALUES APPROACH 50KTS. WITH THE EXPECTED STORM MOTION
A GENERAL ERLY DIRECTION...THINK THE BEST SHOT OF STRONG/SEVERE
STORMS WILL BE ALONG THE WI BORDER THROUGH THE AFTN AND TOWARDS
EARLY EVENING OVER THE SCNTRL. WITH THE CLEARING SEEN OVER PORTIONS
OF WRN UPPER MI...LINGERING MID LVL WAA...AND RIGHT REAR AREA OF
UPPER JET...COULD ALSO SEE SOME DEVELOPMENT FARTHER N THAN THE MAIN
AREA...SO WILL CONTINUE TO MENTION ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS OVER THE WEST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EDT WED JUL 25 2012
ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED
OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST
EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA
FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7
MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC
LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM
FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG
AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM
SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE
EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT
RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT
STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY
STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES
NEAR IWD WITHIN THE NEXT 2-3 HRS.
NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE
TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS
COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A
CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL
FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON
NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL
CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN
THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS
NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT.
LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL
AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR
WEST HALF AND SOON THERE AFTER IN THE EAST.
WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE
CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY
MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX
THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT
SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT
OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER
SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO
MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND
OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT
HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF
MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE
SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY
COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN
OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING.
LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN
WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW
COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN
THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT
SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL
AFTER DAYBREAK ON THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 439 AM EDT WED JUL 25 2012
BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER
NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING
STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT
NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE
FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS
FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT
CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL
PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS
BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR.
ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING
UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE
AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY
100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED
ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF
CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM
PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS
EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH
PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT
INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE
ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS
/BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN
BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN
2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND
SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW
RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING
THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM
LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT.
500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER
GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL
MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND
NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY
LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL
CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST
AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO
SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL
LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN
PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE
WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON
THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN
WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY
CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS
DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE
INFLUENCE.
500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE
THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES
ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES
RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE
THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK
SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG
RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND
RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING
INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF
NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE
AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH
MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUL 25 2012
SHRA/TSRA WORKING THROUGH UPPER MICHIGAN. EXPECT CONDITIONS TO
DETERIORATE THROUGH THE DAY. RAIN COULD BE HEAVY AT TIMES...WITH
VSBY LIKELY REDUCED TO AT LEAST MVFR RANGE THRU THE MORNING. SHOULD
BE PRETTY QUICK LOWERING OF CIGS AS WELL INTO THE IFR RANGE AT BOTH
CMX AND SAW. SLIGHTLY HIGHER CIGS AT IWD DUE TO LESS FAVORABLE EAST
FLOW. EXPECT CONDITIONS TO DROP TO IFR/LIFR TNGT AT ALL SITES WITH
LLVL MSTR LINGERING UNDER LGT UPSLOPE WIND COMPONENT OFF LK SUP/SOME
MID LVL DRYING IN THE WAKE OF DEPARTING DISTURBANCE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM EDT WED JUL 25 2012
LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE
EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND
STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER
GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN
MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT
WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR
EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW
MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE
LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20 KTS THROUGH THE
WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...JLA
LONG TERM...JMW
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1225 PM EDT WED JUL 25 2012
.SYNOPSIS...
ISSUED AT 345 AM EDT WED JUL 25 2012
A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME
HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW
PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD
FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS
TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN.
TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT
THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND
STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 1224 PM EDT WED JUL 25 2012
AREA OF SHOWERS AND STORMS HAVE TRIED TO MOVE INTO THE FORECAST
AREA THIS MORNING. FOR THE MOST PART THESE SHOWERS AND STORMS HAVE
DISSIPATED AS THEY MOVE INTO MUCH LESS INSTABILITY AND MOISTURE.
THE BETTER INSTABILITY DOES NOT MOVE INTO THE AREA UNTIL LATE THIS
AFTERNOON AND EVENING. THE NEXT FEW HOURS LOOK TO BE QUIET.
THE MAIN FOCUS FOR SHOWERS AND STORMS WILL BE FROM EARLY
EVENING...500PM-600PM THROUGH 100AM-200AM. ADDITIONAL STORMS ARE
EXPECTED OVERNIGHT. A COUPLE OF SCENARIOS ARE POSSIBLE FOR LATER
TODAY. THE FIRST SCENARIO IS THAT STORMS TO THE NORTH AND WEST
WILL MOVE INTO THE CWA FROM THE NORTH AND WEST AFTER DEVELOPING
THIS AFTERNOON. THE SECOND IS STORMS FIRE ALONG OUTFLOWS FROM
PRIOR CONVECTION VERY NEAR THE CWA OR OVER THE NORTHERN CWA THIS
AFTERNOON AND EVENING. EITHER WAY WE ARE EXPECTED STORMS TO PRESS
INTO AND MOVE THROUGH THE NORTHERN HALF OR SO OF THE FORECAST
AREA...ROUGHLY I96 NORTH...THIS EVENING.
DAMAGING WINDS LOOK TO BE THE MAIN THREAT AS 40-50 KNOTS OF WIND
WILL BE PRESENT BETWEEN 850MB AND 500MB/S. 35 TO 45 KNOTS OF 0-6KM
SHEAR IS PRESENT AS WELL WHICH WILL AID THUNDERSTORM UPDRAFTS AND
ALLOW FOR ROTATION. IF DISCRETE STORMS CAN DEVELOP AND MOVE ALONG
BOUNDARIES A TORNADO THREAT MAY DEVELOP AS WELL. DAMAGING WINDS
WILL AGAIN BE THE MAIN THREAT WITH A MUCH LOWER TORNADO AND HAIL
THREAT. FREEZING LEVELS SHOULD RISE TO AROUND 16000FT SO ONLY THE
STRONGEST OF UPDRAFTS WOULD BE CAPABLE OF SEVERE HAIL.
CANNOT RULE OUT SEVERE STORMS OVERNIGHT AS WELL AS INSTABILITY
WILL PERSIST GIVEN HIGH DEW POINTS AND THE 850MB LLJ WILL BE
OVERHEAD. MAIN TIME FRAME OF CONCERN THOUGH IS THIS EVENING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 345 AM EDT WED JUL 25 2012
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST
PERIOD AND TO ASSESS SEVERE WX POTENTIAL.
THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A
STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD
FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT
INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER
SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR
ORGANIZED SEVERE STORMS.
00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS
OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO
SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH
IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE
EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT
AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING
WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY
RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75
TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH
DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT.
THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE
THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE
EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND
40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE
PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR
PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE
DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS
EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE
WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED.
THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT
THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL
JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS
SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION
IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY.
THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE
HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION
LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM
FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS
NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS
PROPAGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR
EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING.
IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A
ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON
PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS
WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS
NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES
OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN.
EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR
CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN.
STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE
OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA
THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY
STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY
STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX
THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 AM EDT WED JUL 25 2012
THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS
THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE
AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND
COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS
SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH
THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE.
SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER
ARRIVES FROM THE NORTH.
MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA
OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES
OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED
TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE
IN THE LOWER TO MID 80S WITH LOWS AROUND 60.
SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR
MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE
BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN
DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY
SCATTERED COVERAGE EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 754 AM EDT WED JUL 25 2012
THERE IS CONSIDERABLE UNCERTAINTY ON EXACTLY HOW THINGS ARE GOING
TO PLAY OUT TODAY AND TONIGHT AS FAR AS TSTM ACTIVITY GOES.
IN THE SHORT TERM... THE BAND OF TSTMS MOVING EAST FROM THE
CHICAGO AND MKE AREAS EXTRAPOLATES EAST ACROSS SRN LWR MI BETWEEN
ROUGHLY 14Z TO 18Z. THE CLOUD BASES... AS WELL AS THE VSBYS... WITH
THESE TSTMS ARE MOSTLY IN THE VFR CATEGORY... BUT A TEMPO DIP
INTO MVFR CATEGORY CANNOT BE RULED OUT ESPECIALLY AT GRR AND MKG.
AFTER 18Z OR SO... WILL GO WITH THE IDEA THAT THE WARM SECTOR WILL
SWEEP INTO THE REGION FROM THE SOUTHWEST AND THE ATMOSPHERE WILL
BECOME TOO CAPPED /IE TOO WARM ALOFT/ FOR CONVECTION. SSW SFC
WINDS SHOULD INCREASE AND BECOME GUSTY WITH THE ARRIVAL OF THE
WARM SECTOR.
WILL HOLD OFF ON REINTRODUCING TSTMS IN THE TAFS UNTIL AFTER 00Z
AT MKG AND AFTER 03Z-04Z FARTHER SOUTH ALONG THE I-94 CORRIDOR.
SOME GUIDANCE SUGGEST IT MAY EVEN BE LATER THAN THESE TIMES AS THE
COLD FRONT ISNT REALLY DROPPING IN FROM THE NW UNTIL AFTER 06Z.
&&
.MARINE...
ISSUED AT 1224 PM EDT WED JUL 25 2012
WILL BE ISSUING A SMALL CRAFT ADVISORY AND A BEACH HAZARDS
STATEMENT FOR GRAND HAVEN NORTHWARD. THE TIME FRAME WILL BE FROM
THE CURRENT TIME THROUGH 400 AM TONIGHT WITH THE MAIN TIME FRAME
BEING THIS AFTERNOON AND EVENING. WAVES HAVE ALREADY BUILT TO NEAR
6.5 FEET AT THE LUDINGTON BUOY WITH SOUTHERLY WINDS IN THE 20-30
KNOT RANGE IN THE NORTHERN NEARSHORE WATERS BASED ON OBSERVATIONS.
WEBCAMS ON THE COAST ARE SHOWING WHITECAPS FROM MUSKEGON
NORTHWARD. THE WIND SHOULD TONE DOWN OVERNIGHT WITH THE THREAT
POTENTIALLY SHIFTING SOUTH OF GRAND HAVEN INTO THURSDAY MORNING. A
SCA AND BH.S MAY BE NEEDED FROM DAYBREAK INTO THE AFTERNOON ON
THURSDAY. THIS THREAT WILL BE REEVALUATED OVERNIGHT.
&&
.HYDROLOGY...
ISSUED AT 345 AM EDT WED JUL 25 2012
RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY
ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER
THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES
TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF
THE APPROACHING COLD FRONT TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ037-043-050.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT THURSDAY FOR LMZ847>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...LAURENS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
754 AM EDT WED JUL 25 2012
.SYNOPSIS...
ISSUED AT 345 AM EDT WED JUL 25 2012
A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME
HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW
PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD
FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS
TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN.
TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT
THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND
STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 345 AM EDT WED JUL 25 2012
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST
PERIOD AND TO ASSESS SEVERE WX POTENTIAL.
THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A
STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD
FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT
INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER
SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR
ORGANIZED SEVERE STORMS.
00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS
OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO
SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH
IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE
EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT
AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING
WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY
RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75
TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH
DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT.
THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE
THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE
EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND
40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE
PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR
PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE
DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS
EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE
WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED.
THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT
THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL
JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS
SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION
IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY.
THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE
HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION
LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM
FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS
NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS
PROPOGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR
EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING.
IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A
ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON
PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS
WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS
NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES
OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN.
EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR
CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN.
STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE
OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA
THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY
STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY
STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX
THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 AM EDT WED JUL 25 2012
THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS
THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE
AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND
COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS
SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH
THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE.
SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER
ARRIVES FROM THE NORTH.
MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA
OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES
OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED
TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE
IN THE LOWER TO MID 80S WITH LOWS AROUND 60.
SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR
MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE
BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN
DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY
SCATTERED COVERAGE EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 754 AM EDT WED JUL 25 2012
THERE IS CONSIDERABLE UNCERTAINTY ON EXACTLY HOW THINGS ARE GOING
TO PLAY OUT TODAY AND TONIGHT AS FAR AS TSTM ACTIVITY GOES.
IN THE SHORT TERM... THE BAND OF TSTMS MOVING EAST FROM THE
CHICAGO AND MKE AREAS EXTRAPOLATES EAST ACROSS SRN LWR MI BETWEEN
ROUGHLY 14Z TO 18Z. THE CLOUD BASES... AS WELL AS THE VSBYS... WITH
THESE TSTMS ARE MOSTLY IN THE VFR CATEGORY... BUT A TEMPO DIP
INTO MVFR CATEGORY CANNOT BE RULED OUT ESPECIALLY AT GRR AND MKG.
AFTER 18Z OR SO... WILL GO WITH THE IDEA THAT THE WARM SECTOR WILL
SWEEP INTO THE REGION FROM THE SOUTHWEST AND THE ATMOSPHERE WILL
BECOME TOO CAPPED /IE TOO WARM ALOFT/ FOR CONVECTION. SSW SFC
WINDS SHOULD INCREASE AND BECOME GUSTY WITH THE ARRIVAL OF THE
WARM SECTOR.
WILL HOLD OFF ON REINTRODUCING TSTMS IN THE TAFS UNTIL AFTER 00Z
AT MKG AND AFTER 03Z-04Z FARTHER SOUTH ALONG THE I-94 CORRIDOR.
SOME GUIDANCE SUGGEST IT MAY EVEN BE LATER THAN THESE TIMES AS THE
COLD FRONT ISNT REALLY DROPPING IN FROM THE NW UNTIL AFTER 06Z.
&&
.MARINE...
ISSUED AT 345 AM EDT WED JUL 25 2012
00Z GLERL WAVE MODEL GUIDANCE SUGGESTS WAVE HEIGHTS SHOULD STAY
BELOW SCA CRITERIA TODAY BUT SOUTHERLY WINDS WILL RAMP UP TO 10 TO
20 KTS LATER TODAY WHICH WILL KICK WAVE HEIGHTS UP TO AT LEAST 2 TO
3 FEET WITH HIGHEST WAVES UP TOWARD BIG AND LITTLE SABLE POINTS.
THUNDERSTORMS WILL POSE A HAZARD TO MARINERS THROUGH AT LEAST MIDDAY
THURSDAY.
&&
.HYDROLOGY...
ISSUED AT 345 AM EDT WED JUL 25 2012
RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY
ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER
THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES
TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF
THE APPROACHING COLD FRONT TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
748 AM EDT WED JUL 25 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EDT WED JUL 25 2012
ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED
OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST
EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA
FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7
MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC
LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM
FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG
AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM
SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE
EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT
RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT
STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY
STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES
NEAR IWD WITHIN THE NEXT 2-3 HRS.
NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE
TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS
COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A
CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL
FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON
NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL
CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN
THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS
NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT.
LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL
AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR
WEST HALF AND SOON THERE AFTER IN THE EAST.
WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE
CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY
MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX
THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT
SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT
OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER
SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO
MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND
OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT
HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF
MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE
SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY
COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN
OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING.
LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN
WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW
COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN
THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT
SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL
AFTER DAYBREAK ON THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 439 AM EDT WED JUL 25 2012
BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER
NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING
STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT
NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE
FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS
FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT
CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL
PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS
BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR.
ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING
UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE
AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY
100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED
ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF
CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM
PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS
EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH
PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT
INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE
ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS
/BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN
BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN
2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND
SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW
RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING
THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM
LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT.
500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER
GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL
MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND
NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY
LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL
CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST
AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO
SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL
LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN
PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE
WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON
THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN
WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY
CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS
DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE
INFLUENCE.
500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE
THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES
ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES
RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE
THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK
SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG
RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND
RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING
INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF
NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE
AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH
MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 747 AM EDT WED JUL 25 2012
SHRA/TSRA WORKING THROUGH UPPER MICHIGAN. EXPECT CONDITIONS TO
DETERIORATE THROUGH THE DAY. RAIN COULD BE HEAVY AT TIMES...WITH
VSBY LIKELY REDUCED TO AT LEAST MVFR RANGE THRU THE MORNING. SHOULD
BE PRETTY QUICK LOWERING OF CIGS AS WELL INTO THE IFR RANGE AT BOTH
CMX AND SAW. SLIGHTLY HIGHER CIGS AT IWD DUE TO LESS FAVORABLE EAST
FLOW. EXPECT CONDITIONS TO DROP TO IFR/LIFR TNGT AT ALL SITES WITH
LLVL MSTR LINGERING UNDER LGT UPSLOPE WIND COMPONENT OFF LK SUP/SOME
MID LVL DRYING IN THE WAKE OF DEPARTING DISTURBANCE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM EDT WED JUL 25 2012
LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE
EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND
STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER
GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN
MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT
WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR
EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW
MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE
LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20 KTS THROUGH THE
WEEKEND.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JMW
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
444 AM EDT WED JUL 25 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EDT WED JUL 25 2012
ACTIVE WEATHER MORNING AS COMPLEX OF THUNDERSTORMS THAT HAS FORMED
OVR NORTHERN MN IS POISED TO IMPACT MUCH OF CWA THROUGH AT LEAST
EARLY AFTN. TSRA OVR WCNTRL INTO NORTHERN MN DEVELOPED IN AREA OF PVA
FM SHORTWAVE LIFTING INTO NORTHERN MN AND WAS ALSO TIED TO H85-H7
MOISTURE ADVECTION/H7 FGEN AND RIGHT ENTRANCE JET FORCING/ISENTROPIC
LIFT ON 300-305K SFC. COMPLEX IS WELL TO NORTH OF SFC WARM
FRONT...MORE IN LINE WITH NORTHERN GRADIENT OF MLCAPE OVR 2000 J/KG
AND WITHIN AREA OF SUFFICIENT DEEP LAYER SHEAR OVR 40 KTS. 0-1KM
SHEAR TO 40 KTS HAS ALLOWED COLD POOLS TO DEVELOP AND BRIEFLY PROPAGATE
EASTWARD. MOST WIND GUSTS WITH ACTIVITY HAVE BEEN IN THE 30-40 KT
RANGE. COMPLEX WILL CONTINUE EASTWARD BUT MAY LOSE SOME PUNCH AS IT
STRAYS AWAY FM GRADIENT OF MLCAPE. H85-H3 THICKNESSES SUGGEST ANY
STONGER LINEAR SEGMENTS MAY TRY TO DRIFT ESE AS THE COMPLEX PUSHES
NEAR IWD WITHIN THE NEXT 2-3 HRS.
NO REAL BIG CHANGE TO PREVIOUS FCST...THOUGH THAT IS PARTIALLY DUE
TO A LOT OF SCENARIOS OFFERED UP BY VARIOUS GUIDANCE ON HOW THIS
COMPLEX WILL TRANSLATE TO THE EAST THE NEXT FEW HOURS. WENT WITH A
CONSENSUS FM ALL THE SOLUTIONS ALONG WITH PREVIOUS FCST. OVERALL FEEL
FAIRLY CONFIDENT THAT BTWN ONGOING/STRONG H85 MOISTURE TRANSPORT ON
NOSE OF H85 JET AND DIVERGENCE ALOFT...THAT THE OVERALL COMPLEX WILL
CONTINUE TO TRACK ON A GENERAL EASTWARD MOVEMENT ACROSS UPR MICHIGAN
THROUGH EARLY AFTN...ON SOUTH EDGE OF SHORTWAVE MOVING ACROSS
NORTHERN LK SUPERIOR AND STILL WELL TO NORTH OF SFC WARM FRONT.
LATEST RENDITION OF RAPID REFRESH RUC /HRRR/ SHOWS THIS PRETTY WELL
AND INDICATES THAT MAJORITY OF PRECIP WILL BE DONE BY EARLY AFTN OVR
WEST HALF AND SOON THERE AFTER IN THE EAST.
WHAT HAPPENS BY MID TO LATE AFTN IS A CONCERN AS MODELS HAVE
CERTAINLY TRENDED FARTHER NORTH WITH ADVANCING SFC WARM FRONT BY
MID-LATE AFTN. SINCE IT APPEARS NOW THAT BULK OF CONVECTIVE COMPLEX
THIS MORNING WILL JUST GRAZE SOUTHERN CWA IT IS MORE FEASIBLE THAT
SOUTHERN CWA MAY SNEAK INTO WARM SECTOR THIS AFTN AND WITH GRADIENT
OF 0-6KM MUCAPE WELL OVR 2000 J/KG OVERHEAD ALONG WITH ANOTHER
SHORTWAVE WORKING THROUGH IN SPEEDY WESTERLY FLOW IN ADDITION TO
MORE UPPER DIVERGENCE ALOFT...BEGINNING TO THINK AN ADDITIONAL ROUND
OF SHRA/TSRA MAY DEVELOP BY LATE AFTN. IF CONVECTION BEHAVES LIKE IT
HAS OVERNIGHT WITH MOST ACTIVITY OCCURRING ON GRADIENT OF
MLCAPE...THEN PORTIONS OF CWA WOULD BE FAVORED FOR STRONG TSRA LINE
SEGMENTS WITH STRONG/GUSTY WINDS. A LOT WILL DEPEND ON HOW QUICKLY
COMPLEX MOVES THROUGH TODAY AND EXTENT OF DESTABILIZATION THAT CAN
OCCUR LATE TODAY. THREAT FOR STORMS COULD LINGER INTO THE EVENING.
LATER TONIGHT...STRONG UPPER LOW CURRENTLY OVR SOUTHERN SASKATCHEWAN
WILL BE APPROACHING. H7-H3 Q-VECTOR CONVERGENCE AHEAD OF UPR LOW
COULD TRIGGER ELEVATED CONVECTION. TROUBLE IS MOISTURE IS HEAVY IN
THE LOW-LEVELS BUT REALLY DRYING OUT IN THE MID-UPR LEVELS. KEPT
SOME SLIGHT CHANCES IN FCST BUT BETTER CHANCES LIKELY HOLD OFF TIL
AFTER DAYBREAK ON THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 439 AM EDT WED JUL 25 2012
BEGINNING OF THE PERIOD WILL INCLUDE A CLOSED 500MB LOW OVER
NORTHERN MN THAT WILL TRACK SOUTHEASTWARD WHILE LOSING
STRENGTH...CROSSING THE UPPER GREAT LAKES BY NIGHTFALL. AS IT
NEARS...MODEL SOUNDINGS ARE HINTING AT ABUNDANT LEFTOVER MOISTURE
FROM WEDNESDAY/S EXITING SYSTEM...SO WILL CONTINUE WITH PREVIOUS
FORECASTS MENTION OF CLOUDY SKIES...COOLER CONDITIONS...AND A SLIGHT
CHANCE FOR SHRA. THICK CLOUD COVER FROM THE LOW LEVELS UPWARDS WILL
PREVENT MUCH IN THE WAY OF RADIATIVE HEATING...SO WILL KEEP TEMPS
BELOW NORMAL...BARELY REACHING THE 70 MARK NEAR LAKE SUPERIOR.
ALL MODELS SEEM TO BE IN GOOD AGREEMENT OF SOME PRECIP TRAVERSING
UPPER MI THURSDAY NIGHT AS A RESULT OF THIS UPPER LEVEL DISTURBANCE
AND ASSOCIATED SURFACE WARM FRONT. THOUGH PWAT VALUES ARE ONLY
100-120 PERCENT OF NORMAL...ABUNDANT LINGERING MOISTURE MENTIONED
ABOVE SHOULD BE ENOUGH TO SPARK SOME PRECIP ALONG THE MAIN LINE OF
CONVERGENCE/WARM FRONT/ AS IT PASSES OVER. HOWEVER...A PROBLEM
PERSISTS ON THE EXACT LOCATION OF THE PRECIP AND CONVERGENCE...AS
EVERY MODEL SEEMS TO HAVE A SLIGHTLY DIFFERENT SOLUTION IN WHICH
PART OF UPPER MI WILL SEE THE BEST RAINFALL CHANCES THURSDAY NIGHT
INTO FRIDAY. LATEST NAM SHOWS BEST MU CAPE VALUES TO ARRIVE WITH THE
ONSET OF THE FRONTAL PASSAGE AND DIMINISH DURING THE OVERNIGHT HOURS
/BY 03Z/...WITH HIGHEST VALUES /1-1.5 J/KG/ NEAR THE WISCONSIN
BORDER. HOWEVER 0-3KM COMPUTED CAPE VALUES ONLY TOP OUT BETWEEN
2-300 J/KG...WITH THE NAM FORECASTED CAPE PROFILE VERY LONG AND
SKINNY...INDICATIVE OF ONLY ISOLATED CHANCES. TO SUM UP THEN...A FEW
RUMBLES OF THUNDER AND FLASHES OF LIGHTNING COULD BE POSSIBLE DURING
THE EVENING WHEN INSTABILITY IS AT ITS BEST...BUT OTHERWISE AM
LEANING TOWARDS THIS MAINLY BEING A HEAVY RAIN EVENT.
500MB SHORTWAVE WILL CONTINUE TO WEAKEN AS IT EXITS INTO THE LOWER
GREAT LAKES DURING THE DAY FRIDAY. HOWEVER...LINGERING MOISTURE WILL
MAKE FOR SIMILAR CONDITIONS TO THURSDAY...WITH THICK CLOUD COVER AND
NRLY WINDS MAKING FOR MOIST AND COOLER THAN NORMAL CONDITIONS. MANY
LOCATIONS WILL STRUGGLE TO GET INTO THE 70S. WITH THIS SET UP...WILL
CONTINUE WITH SLIGHT CHANCE POPS DURING THE DAY FRIDAY IN THE WEST
AND CENTRAL...IN THAT SOME LEFT OVER FORCING COULD BE ENOUGH TO
SPAWN SOME SHRA/TSRA...WHILE BEST FORCING AND PRECIP CHANCES WILL
LIE NEAR LAKE MICHIGAN. 500MB RIDGING PATTERN OVER THE NORTHERN
PLAINS WILL BEGIN TO MOVE EASTWARD...WORKING ITS WAY INTO THE
WESTERN PORTIONS OF THE CWA BY LATE FRIDAY AFTERNOON AS IS SEEN ON
THE FORECAST SOUNDINGS...FIRST STARTING IN THE UPPER LEVELS AND THEN
WORKING ITS WAY DOWN TO THE SURFACE. THIS WILL TRANSLATE TO RAPIDLY
CLEARING SKIES FROM WEST TO EAST DURING THE OVERNIGHT HOURS AND LOWS
DROPPING TO THE LOW TO MID 50S INLAND AWAY FROM THE WARMER LAKE
INFLUENCE.
500MB RIDGE AND ASSOCIATED HIGH PRESSURE WILL CONTINUE TO DOMINATE
THROUGH THE DAY ON SUNDAY. THIS WILL TRANSLATE TO MOSTLY SUNNY SKIES
ACROSS THE REGION...LIGHT SOUTHERLY WINDS...AND HIGH TEMPERATURES
RISING TO BACK ABOVE NORMAL. THE 500MB RIDGE SHOULD REMAIN IN PLACE
THROUGHOUT THE REST OF THE FORECAST PERIOD...WITH SEVERAL WEAK
SHORTWAVES TRAVERSING THE RIDGE AND UPPER GREAT LAKES. ALL LONG
RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT SHORTWAVE AND
RESULTING PRECIP WILL TRAVERSE THE UPPER GREAT LAKES SUNDAY EVENING
INTO MONDAY WITH PW VALUES JUMPING BACK UP TO 100-120 PERCENT OF
NORMAL. UNFORTUNATELY...AFTER THIS POINT MODELS START TO LOSE
AGREEMENT ON TIMING AND LOCATIONS OF MENTIONED PRECIP SO WENT WITH
MODEL CONSENSUS FOR REMAINDER OF FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 133 AM EDT WED JUL 25 2012
EXPECT VFR CONDITIONS AT THE START OF THE FCST PERIOD TO GIVE WAY TO
SHRA/SOME TS SW-NE EARLY THIS MRNG IN ADVANCE OF WARM FNT...WITH
THIS PCPN REACHING CMX/SAW ARND SUNRISE. THE RA COULD BE HEAVY AT
TIMES...WITH VSBY LIKELY REDUCED TO AT LEAST MVFR RANGE THRU THE
MORNING. MAINTAINED MENTION OF TS AT IWD AS THIS SITE WL BE CLOSER
TO GREATER INSTABILITY TO THE S. THERE COULD ALSO BE TS AT SAW/
CMX...BUT WEAKER INSTABILITY FARTHER N OF THE WARM FNT INDICATES THE
CHC IS TOO LO TO INCLUDE SPECIFIC MENTION ATTM. ALSO LOWERED CIGS TO
MVFR...AND THESE MAY DROP TO IFR...ESPECIALLY AT SAW/CMX WITH
GREATER UPSLOPE WIND COMPONENT. THE HEAVIER SHRA WL MOVE OUT ON WED
AFTN...WITH IMPROVING VSBY. LO CIGS TO IFR ARE MOST LIKELY AT SAW/
CMX WITH PERSISTENT UPSLOPE WIND COMPONENT/LLVL MSTR LINGERNING N OF
SFC WARM FNT. BEST SHOT FOR VFR CIGS THIS AFTN WL BE AT IWD...WITH
DOWNSLOPING WIND. BUT EVEN THERE...EXPECT CONDITIONS TO DROP TO
IFR/LIFR TNGT WITH LLVL MSTR LINGERING UNDER LGT UPSLOPE WIND
COMPONENT OFF LK SUP/SOME MID LVL DRYING IN THE WAKE OF DEPARTING
DISTURBANCE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 439 AM EDT WED JUL 25 2012
LOW PRESSURE SYSTEM MOVES INTO WISCONSIN LATER TODAY AND INTO THE
EASTERN GREAT LAKES ON THURSDAY MORNING AND INTO THE NEW ENGLAND
STATES ON FRIDAY. THIS WILL LEAVE A WEAK SFC TROUGH OVER THE UPPER
GREAT LAKES LATER TONIGHT THROUGH FRIDAY. HIGH PRESSURE WILL THEN
MOVE OVER THE UPPER GREAT LAKES THIS WEEKEND...LEADING TO LIGHT
WINDS OVER LK SUPERIOR. SOME STRONG E/SE WINDS POSSIBLE TODAY OVR
EASTERN AND NORTHERN SECTIONS OF LK SUPERIOR OUT AHEAD OF THE LOW
MOVING THROUGH AND THEN GUSTY ENE WINDS THIS EVENING IN WAKE OF THE
LOW. OVERALL THOUGH...EXPECT WINDS TO STAY BELOW 20KTS THROUGH THE
WEEKEND. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JMW
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
345 AM EDT WED JUL 25 2012
.SYNOPSIS...
ISSUED AT 345 AM EDT WED JUL 25 2012
A WARM FRONT WILL BRING POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TODAY MAINLY NORTH OF INTERSTATE 96 THIS AFTERNOON. IT WILL BECOME
HOT AND HUMID LATER TODAY SOUTH OF THE WARM FRONT. STRONG LOW
PRESSURE TRACKING EAST ALONG THE WARM FRONT AND AN APPROACHING COLD
FRONT WILL COMBINE TO BRING POTENTIAL FOR STRONG TO SEVERE STORMS
TONIGHT THAT MAY PRODUCE DAMAGING WIND GUSTS AND HEAVY RAIN.
TEMPERATURES WILL RETURN TO CLOSER TO NORMAL BEHIND THAT FRONT
THURSDAY AND FRIDAY WITH A CONTINUED CHANCE OF SOME SHOWERS AND
STORMS. FAIR WEATHER IS ANTICIPATED THIS WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 345 AM EDT WED JUL 25 2012
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE
TIMING/PROBABILITIES FOR CONVECTION THROUGH THE SHORT TERM FCST
PERIOD AND TO ASSESS SEVERE WX POTENTIAL.
THE SETUP LOOKS FAVORABLE FOR STRONG TO SEVERE STORMS TONIGHT AS A
STRONG LOW PRESSURE WAVE TRACKS EAST ALONG THE WARM FRONT AND COLD
FRONT APPROACHES. THERE WILL BE PLENTY OF MOISTURE AND DECENT
INSTABILITY ALONG WITH LIFT FROM THE APPROACHING FRONT. DEEP LAYER
SHEAR VALUES RAMPING UP TO 35 TO 40 KTS ARE ALSO FAVORABLE FOR
ORGANIZED SEVERE STORMS.
00Z 4KM WRF-NMM SIM Z GUIDANCE SHOWS CONVECTIVE DEVELOPMENT ACROSS
OUR AREA FROM 00Z THRU 12Z TONIGHT. 00Z 4KM NSSL WRF GUIDANCE ALSO
SHOWS POTENTIAL TONIGHT ESPECIALLY OVER OUR NORTHERN COUNTIES WHICH
IS ALSO SUPPORTED BY THE 00Z ECMWF. AN ISOLATED TORNADO IS POSSIBLE
EARLY TO MID EVENING WITH A SOMEWHAT VEERED WIND PROFILE WITH HEIGHT
AND DEEP LAYER SHEAR VALUES CONDUCIVE TO SUPERCELLS. DAMAGING
WIND GUSTS SHOULD BE THE MOST LIKELY SEVERE WX THREAT BUT HEAVY
RAINFALL IS ALSO POSSIBLE. PRECIPITABLE WATER VALUES WILL REACH 1.75
TO 2.25 INCHES JUST AHEAD OF THE APPROACHING COLD FRONT ALONG WITH
DECENT LOW TO MID LEVEL MOISTURE POOLING ALONG/AHEAD OF THE FRONT.
THE GREATEST THREAT FOR SVR WX SHOULD COME FROM AROUND 23Z THIS EVE
THROUGH 06Z THUR WITH GREATER INSTABILITY IN PLACE THROUGH THE
EVENING HOURS AND WITH THE CRAVEN BROOKS SIG SVR PARAMETER UP AROUND
40-50K. THIS IS ALSO THE WINDOW OF TIME THAT THE SUPERCELL COMPOSITE
PARAMETER IS FCST TO BE WAY UP AROUND A VALUE OF 12. THE SIG TOR
PARAMETER REACHES VALUES OF 1 TO 4 FROM EARLY TO MID EVENING BEFORE
DROPPING OFF OVERNIGHT. THE BEST CHC FOR AN ISOLATED TORNADO THIS
EVE WOULD BE OVER OUR NORTHERN COUNTIES IN CLOSER PROXIMITY TO THE
WARM FRONT WHERE 0-1KM AND 0-3KM SRH VALUES WILL BE ENHANCED.
THE THREAT FOR SOME SEVERE STORMS WILL LINGER EVEN AFTER 06Z TONIGHT
THROUGH AT LEAST DAYBREAK IF NOT MIDDAY THURSDAY... THE POTENTIAL
JUST WILL NOT BE QUITE AS FAVORABLE AS BETWEEN 23Z-06Z TONIGHT AS
SUGGESTED BY A CONSENSUS OF SPC SREF SVR WX PARAMETERS. THIS NOTION
IS ALSO SUPPORTED BY OUR LOCAL SEVERE WX CLIMATOLOGY.
THE FCST FOR THIS MORNING AND AFTERNOON IS TRICKY. MOST OF THE
HIGHER RESOLUTION GUIDANCE SUGGESTS THE BETTER THREAT FOR CONVECTION
LATER THIS MORNING WILL BE ACROSS NORTHERN MICHIGAN AS THE WARM
FRONT LIFTS NORTH. HOWEVER SIGNIFICANT CONVECTIVE DEVELOPMENT IS
NOTED EARLY THIS MORNING ACROSS CENTRAL MN. I AM CONCERNED ABOUT MCS
PROPOGATION THICKNESS TOOLS WHICH SUGGEST THAT THIS WILL DIVE SE OR
EVEN SSE EVENTUALLY ACROSS WI LATER THIS MORNING.
IF THIS ACTIVITY HOLDS TOGETHER WE COULD ALREADY BE DEALING WITH A
ROUND OF STRONG TO SEVERE STORMS HERE BY EARLY TO MID AFTERNOON
PARTICULARLY OVER OUR NORTHERN COUNTIES. UPSTREAM RGNL RADAR TRENDS
WILL NEED TO BE MONITORED VERY CLOSELY THROUGH THE MORNING. IT IS
NOTED THAT THE SPC SREF DERECHO COMPOSITE PARAMETER REACHES VALUES
OF 2-3 ACROSS WI THIS MORNING AND THEN OVER LWR MI BY THIS AFTN.
EXTRAPOLATION OF LATEST HRRR GUIDANCE ALSO SHOWS THE THREAT FOR
CONVECTION OVER OUR NORTHERN COUNTIES TOWARD MID AFTN.
STILL LOOKING FOR LINGERING SHOWERS/TSTORMS THURSDAY. CANNOT RULE
OUT SOME STRONG TO SEVERE STORMS ESPECIALLY OVER OUR SE FCST AREA
THRU MIDDAY UNTIL THE COLD FRONT CLEARS THAT AREA. SOME STORMS MAY
STILL LINGER EVEN THROUGH THE AFTERNOON AIDED BY A COUPLE OF FAIRLY
STRONG SHORTWAVES TRACKING EAST ACROSS THE AREA. HOWEVER THE SVR WX
THREAT BY THURSDAY AFTERNOON SHOULD BE FURTHER SOUTH ACROSS IN/OH.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 AM EDT WED JUL 25 2012
THE UPPER LOW OVER SASKATCHEWAN IS PROGGED TO DROP SOUTHEAST ACROSS
THE GREAT LAKES REGION THURSDAY NIGHT AND FRIDAY. AS THIS FEATURE
AND ASSOCIATED COLDER TEMPS ALOFT COME OVERHEAD ON FRIDAY AND
COMBINE WITH SFC HEATING/INSTABILITY ... COVERAGE OF SHOWER/TSTMS
SHOULD INCREASE BY AFTERNOON. A WEAK SFC TROUGH DROPPING SOUTH
THROUGH LWR MI ON FRIDAY IS EXPECTED TO ENHANCE SFC CONVERGENCE.
SHOWERS WILL END FRIDAY EVENING AS THE WAVE MOVES OUT AND DRIER
ARRIVES FROM THE NORTH.
MODELS HAVE BEEN CONSISTENT FOR SEVERAL RUNS NOW IN SHOWING AN AREA
OF SFC HIGH PRESSURE DRIFTING SLOWLY EAST ACROSS THE GREAT LAKES
OVER THE COMING WEEKEND. A PLEASANT/COMFORTABLE AIR MASS IS EXPECTED
TO ACCOMPANY THIS FEATURE WITH DEW POINTS AROUND 60. HIGHS SHOULD BE
IN THE LOWER TO MID 80S WITH LOWS AROUND 60.
SHOWER/TSTM CHANCES WILL BE REINTRODUCED EARLY NEXT WEEK AS THE AIR
MASS GRADUALLY BECOMES A BIT WARMER AND INCREASINGLY HUMID ON THE
BACK SIDE OF THE SFC HIGH. HOWEVER RIGHT NOW THE CHANCES FOR RAIN
DO NOT LOOK PARTICULARLY GOOD... WITH ONLY ISOLATED TO WIDELY
SCATTERED COVERAGE EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1203 AM EDT WED JUL 25 2012
VFR THROUGH WEDNESDAY WITH SOME SCATTERED THUNDERSTORMS POSSIBLE
BY LATE WEDNESDAY AFTERNOON. SOUTHWEST WINDS WILL PICK UP
WEDNESDAY MORNING WITH SOME GUSTS OVER 20 KNOTS POSSIBLE WEDNESDAY
AFTERNOON.
&&
.MARINE...
ISSUED AT 345 AM EDT WED JUL 25 2012
00Z GLERL WAVE MODEL GUIDANCE SUGGESTS WAVE HEIGHTS SHOULD STAY
BELOW SCA CRITERIA TODAY BUT SOUTHERLY WINDS WILL RAMP UP TO 10 TO
20 KTS LATER TODAY WHICH WILL KICK WAVE HEIGHTS UP TO AT LEAST 2 TO
3 FEET WITH HIGHEST WAVES UP TOWARD BIG AND LITTLE SABLE POINTS.
THUNDERSTORMS WILL POSE A HAZARD TO MARINERS THROUGH AT LEAST MIDDAY
THURSDAY.
&&
.HYDROLOGY...
ISSUED AT 345 AM EDT WED JUL 25 2012
RIVER LEVELS REMAIN LOW AND RAINFALL IS NOT EXPECTED TO BE HEAVY
ENOUGH TO CAUSE SIGNIFICANT RIVER FLOODING ISSUES. HOWEVER
THUNDERSTORMS MAY CAUSE URBAN AND SMALL STREAM TYPE FLOODING ISSUES
TONIGHT WITH HIGH PRECIPITABLE WATER VALUES IN PLACE IN ADVANCE OF
THE APPROACHING COLD FRONT TONIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...OSTUNO
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
259 PM CDT WED JUL 25 2012
.DISCUSSION.../ISSUED 259 PM CDT WED JUL 25/
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.../18Z TAF ISSUANCE/
SURFACE LOW IS CURRENTLY SITTING OVER THE FORECAST AREA AND
DRIFTING SOUTHEAST. THERE IS A WIND SHIFT ALONG THE SURFACE
LOW/TROUGH AXIS... ALTHOUGH THE TRUE COLD FRONT STILL LAGS
UPSTREAM OVER THE DAKOTAS WHERE THE DEWPOINT GRADIENT CAN BE SEEN
ALONG WITH A SECONDARY TROUGH. THIS MEANS SOME INSTABILITY LAGS
THE BOUNDARY BY A BIT... AND THE UPPER WAVE IS ALSO STILL LOCATED
UPSTREAM. SO... ALTHOUGH THIS INITIAL BOUNDARY IS PUSHING THROUGH
AND BRINGING SOME CHANCE FOR PCPN... THERE IS THE POTENTIAL FOR
REDEVELOPMENT LATER THIS AFTERNOON AND EVENING AS THE UPPER WAVE
AND FRONTAL BOUNDARY WORK INTO THE AREA. HOWEVER... AT THIS POINT
MOST OF THE GUIDANCE SUGGESTS THINGS WILL COALESCE BEST JUST
SOUTHEAST OF MOST OF THE TAF SITES... WITH PERHAPS KEAU HAVING THE
BEST CHANCE OF SEEING ANY BONAFIDE ACTIVITY. WILL BEAR WATCHING...
AND AMENDMENTS WILL CERTAINLY BE POSSIBLE. OTHERWISE... VFR
CONDITIONS WILL PREDOMINATE AND WINDS WILL BE SHIFTING AROUND TO
THE NORTHWEST THIS AFTERNOON INTO THE EVENING FROM WEST TO EAST.
KMSP... PRIMARY UNCERTAINTY IN TAFS IS WITH CHANCES FOR SHRA/TSRA
THIS AFTERNOON. PLAYED THINGS CONSERVATIVELY FOR NOW... BUT
AMENDMENTS MAY BE NEEDED SHOULD SHRA/TSRA REDEVELOP NEAR/UPSTREAM
OF KMSP RATHER THAN THE ANTICIPATED DOWNSTREAM.
//OUTLOOK FOR KMSP FOR THURSDAY NIGHT THROUGH MONDAY
THURSDAY NIGHT...SHRA AND MVFR CEILINGS AND VISIBILITIES POSSIBLE.
FRIDAY...MVFR CEILINGS POSSIBLE EARLY.
FRIDAY NIGHT THROUGH SATURDAY...VFR EXPECTED.
SATURDAY NIGHT THROUGH SUNDAY...BRIEF MVFR CEILINGS VISIBILITIES
POSSIBLE WITH SHRA/TSRA.
SUNDAY NIGHT AND MONDAY...VFR EXPECTED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LRS/TRH
AREA FORECAST DISCUSSION
NWS DULUTH MN
1230 PM CDT WED JUL 25 2012
.AVIATION...18Z TAFS
LOW PRESSURE IN SOUTH CENTRAL MINNESOTA WILL MOVE EAST THIS
AFTERNOON...AS AN UPPER LEVEL TROUGH DIVES TOWARD NORTHERN
MINNESOTA REACHING THAT AREA THURSDAY MORNING. A MIXTURE OF IFR TO
VFR CEILINGS COVERED THE NORTHLAND...AND WE EXPECT MOST AREAS TO
REMAIN OR BECOME MVFR AS ANY CLEAR AREAS FILL IN WITH CUMULUS. A
FEW SHOWERS WILL ALSO BE POSSIBLE...BUT COVERAGE WILL BE LIMITED.
A BETTER CHANCE FOR SHOWERS AND STORMS WILL OCCUR THIS
EVENING...MAINLY OVER WESTERN AREAS. THIS AREA WILL MOVE EAST
OVERNIGHT AS THE TROUGH MOVES CLOSER. WE LIMITED THE MENTION OF
PRECIP THIS EVENING/OVERNIGHT TO THE KINL/KBRD/KHIB TAFS ATTM.
AMENDMENTS OR LATER FORECASTS MAY ADD TO THE OTHER TAFS.
FOG WILL ALSO BE AN ISSUE TONIGHT AS PLENTY OF LOW LEVEL MOISTURE
COVERS THE AREA. WE PUT VSBYS THE LOWEST AT KDLH WHICH WILL SEE
LIGHT ONSHORE WINDS TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 948 AM CDT WED JUL 25 2012/
UPDATE...
NOW THAT MUCH OF THE RAIN HAS MOVED OUT OF THE EASTERN FA WITH THE
LOW PRESSURE SYSTEM MOVING THROUGH THE MINNESOTA AND WESTERN LAKE
SUPERIOR REGION...UPDATED THE GRIDS THROUGH THIS EVENING. THINK
THE LINGERING RAIN AND THUNDER WILL CONTINUE TO MOVE OUT OF THE
EASTERN FA THIS MORNING...AND ANOTHER CLUSTER OF RAIN AND THUNDER
IN CENTRAL MN WILL MOVE ACROSS THE SOUTHERN FA THIS MORNING AS IT
FALLS APART. THIS IS SUPPORTED BY RECENT HRRR AND NAM MODEL RUNS.
THEN FOR THIS AFTERNOON...THERE ARE TWO MAIN AREAS WHERE THERE MAY
BE REDEVELOPMENT OF STORMS. THE NAM/WRF/HRRR ARE IN FAIRLY GOOD
AGREEMENT THAT THERE MAY BE REDEVELOPING STORMS NEAR OR JUST
SOUTHEAST OF THE SOUTHEASTERN FA THIS AFTERNOON NEAR THE COLD
FRONT MOVING THROUGH THE REGION. ALSO...THERE MAY BE STORMS LATE
THIS AFTERNOON OR THIS EVENING IN THE WESTERN FA NEAR THE
SECONDARY COLD FRONT ASSOCIATED WITH THE POTENT SHORTWAVE COMING
OUT OF CANADA. BOTH AREAS COULD SEE SOME STRONG...MAYBE
SEVERE...THUNDERSTORMS DUE TO ADEQUATE INSTABILITY AND SHEAR. KEPT
LOW CHANCES OF PCP FOR THE REST OF THE FA THROUGH THIS EVENING TO
ACCOUNT FOR ANY MARGINS OF ERROR.
&&
PREV DISCUSSION... /ISSUED 358 AM CDT WED JUL 25 2012/
SHORT TERM...LATEST REGIONAL RADAR MOSAIC SHOWS WIDESPREAD
SHOWERS AND STORMS OVERSPREADING OUR MN ZONES EARLY THIS
MORNING...WITH SC TD SHOWERS AND STORMS ACROSS OUR WI ZONES. THIS
ACTIVITY IS ASSOCIATED WITH A FAIRLY STRONG SHORTWAVE PROPAGATING
WED ACROSS THE MIDWEST EARLY THIS MORNING. WITH MUCAPE VALUES
RANGING FROM 1000-3000 J/KG AND SRH VALUES RANGING FROM 200 TO 400
M2/S2 ACROSS THE REGION...INITIALLY THE CONVECTION WAS QUITE
ORGANIZED ACROSS WRN MN RESULTING IN ISOLD SVR STORMS. CURRENTLY
THE STRENGTH OF THE CONVECTION HAS WEAKENED WITH HEAVY RAIN BEING
THE MAIN CONCERN AS IT SPREADS EAST ACROSS OUR CWA. THE LATEST SPC
RUC ANALYSIS SHOWS PWAT VALUES RANGING FROM 1.5 TO 2 INCHES ACROSS
MOST OF THE CWA. HOWEVER WITH THE FLOW ALOFT BEING FAIRLY
PROGRESSIVE...THE RAIN SHOULD TAPER OFF FROM THE WEST BY THIS
AFTERNOON...AND END ACROSS OUR SERN ZONES THIS EVENING. EVEN
SO...WE WILL KEEP THE FF WATCH IN EFFECT FOR THE NORTHSHORE DUE TO
PREVIOUS FLOOD DAMAGE FROM A MONTH AGO AND FAST REACTING
STREAMS/CREEKS THE NORTHSHORE.
A RESPITE IN THE PRECIPITATION IS EXPECTED FOR TONIGHT BEFORE A
POTENT UPPER TROUGH OVER SRN CANADA IS PROGGED TO DIG SEWD OVER
THE NORTHLAND ON THURSDAY. THE SECOND ROUND OF SHOWERS AND STORMS
SHOULD BE FAIRLY WIDESPREAD...BUT NOT AS STRONG OR HEAVY.
TEMPERATURES TODAY SHOULD BE SEASONABLY WARM IF THERE ARE SOME
BREAKS IN THE RAIN AND CLOUD COVER. HOWEVER WITH THE UPPER TROUGH
OVER THE WRN GREAT LAKES TOMORROW...TEMPS WILL BE SEASONABLY COOL
WITH HIGHS ONLY IN THE LOWER TO MID 70S FOR MOST LOCATIONS.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
A SHORTWAVE WILL CONTINUE TO MOVE THROUGH THE REGION THURSDAY
NIGHT INTO FRIDAY...WITH SOME LINGERING SHOWERS AND THUNDERSTORMS.
WE WILL CONTINUE IN A GENERAL NW FLOW PATTERN FROM LATE IN THE
WEEK INTO THE WEEKEND. IN GENERAL...THERE WILL CONTINUE TO BE A
CHANCE OF SHOWERS AND THUNDERSTORMS FOR MOST OF THE PERIODS DURING
THE EXTENDED TIME FRAME. TEMPERATURES WILL CONTINUE TO BE QUITE
WARM...WITH 80S TO LOWER 90S THROUGHOUT THE PERIOD. NOT REALLY A
LOT OF FEATURES THROUGHOUT THE EXTENDED PERIOD...SO MAINLY LOOKING
AT SOME DIURNAL PRECIPITATION DUE TO SUBTLE FEATURES.
&&
.POINT TEMPS/POPS...
DLH 59 73 57 76 / 20 70 50 30
INL 56 72 55 78 / 40 70 40 10
BRD 62 77 59 78 / 20 50 20 10
HYR 59 78 58 77 / 20 60 50 20
ASX 59 76 59 74 / 20 60 50 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
948 AM CDT WED JUL 25 2012
.UPDATE...
NOW THAT MUCH OF THE RAIN HAS MOVED OUT OF THE EASTERN FA WITH THE
LOW PRESSURE SYSTEM MOVING THROUGH THE MINNESOTA AND WESTERN LAKE
SUPERIOR REGION...UPDATED THE GRIDS THROUGH THIS EVENING. THINK
THE LINGERING RAIN AND THUNDER WILL CONTINUE TO MOVE OUT OF THE
EASTERN FA THIS MORNING...AND ANOTHER CLUSTER OF RAIN AND THUNDER
IN CENTRAL MN WILL MOVE ACROSS THE SOUTHERN FA THIS MORNING AS IT
FALLS APART. THIS IS SUPPORTED BY RECENT HRRR AND NAM MODEL RUNS.
THEN FOR THIS AFTERNOON...THERE ARE TWO MAIN AREAS WHERE THERE MAY
BE REDEVELOPMENT OF STORMS. THE NAM/WRF/HRRR ARE IN FAIRLY GOOD
AGREEMENT THAT THERE MAY BE REDEVELOPING STORMS NEAR OR JUST
SOUTHEAST OF THE SOUTHEASTERN FA THIS AFTERNOON NEAR THE COLD
FRONT MOVING THROUGH THE REGION. ALSO...THERE MAY BE STORMS LATE
THIS AFTERNOON OR THIS EVENING IN THE WESTERN FA NEAR THE
SECONDARY COLD FRONT ASSOCIATED WITH THE POTENT SHORTWAVE COMING
OUT OF CANADA. BOTH AREAS COULD SEE SOME STRONG...MAYBE
SEVERE...THUNDERSTORMS DUE TO ADEQUATE INSTABILITY AND SHEAR. KEPT
LOW CHANCES OF PCPN FOR THE REST OF THE FA THROUGH THIS EVENING TO
ACCOUNT FOR ANY MARGINS OF ERROR.
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT WED JUL 25 2012/
AVIATION.../12Z TAF ISSUANCE/
CLOUD AND VSBY CONDITIONS WILL BE QUITE VARIABLE FOR A TIME THIS
MORNING BEFORE BECOMING GENERALLY VFR AS THE DAY WEARS ON. THE
NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN PORTION OF
THE AREA WILL GRADUALLY GIVE WAY TO SCATTERED SHOWERS AND STORMS.
DRIER AIR WILL WORK IN FROM THE WEST THIS AFTERNOON...BUT SOME
SHOWERS AND STORMS WILL STILL BE AROUND.
PREV DISCUSSION... /ISSUED 358 AM CDT WED JUL 25 2012/
SHORT TERM...LATEST REGIONAL RADAR MOSAIC SHOWS WIDESPREAD
SHOWERS AND STORMS OVERSPREADING OUR MN ZONES EARLY THIS
MORNING...WITH SCTD SHOWERS AND STORMS ACROSS OUR WI ZONES. THIS
ACTIVITY IS ASSOCIATED WITH A FAIRLY STRONG SHORTWAVE PROPAGATING
EWD ACROSS THE MIDWEST EARLY THIS MORNING. WITH MUCAPE VALUES
RANGING FROM 1000-3000 J/KG AND SRH VALUES RANGING FROM 200 TO 400
M2/S2 ACROSS THE REGION...INITIALLY THE CONVECTION WAS QUITE
ORGANIZED ACROSS WRN MN RESULTING IN ISOLD SVR STORMS. CURRENTLY
THE STRENGTH OF THE CONVECTION HAS WEAKENED WITH HEAVY RAIN BEING
THE MAIN CONCERN AS IT SPREADS EAST ACROSS OUR CWA. THE LATEST SPC
RUC ANALYSIS SHOWS PWAT VALUES RANGING FROM 1.5 TO 2 INCHES ACROSS
MOST OF THE CWA. HOWEVER WITH THE FLOW ALOFT BEING FAIRLY
PROGRESSIVE...THE RAIN SHOULD TAPER OFF FROM THE WEST BY THIS
AFTERNOON...AND END ACROSS OUR SERN ZONES THIS EVENING. EVEN
SO...WE WILL KEEP THE FF WATCH IN EFFECT FOR THE NORTHSHORE DUE TO
PREVIOUS FLOOD DAMAGE FROM A MONTH AGO AND FAST REACTING
STREAMS/CREEKS THE NORTHSHORE.
A RESPITE IN THE PRECIPITATION IS EXPECTED FOR TONIGHT BEFORE A
POTENT UPPER TROUGH OVER SRN CANADA IS PROGGED TO DIG SEWD OVER
THE NORTHLAND ON THURSDAY. THE SECOND ROUND OF SHOWERS AND STORMS
SHOULD BE FAIRLY WIDESPREAD...BUT NOT AS STRONG OR HEAVY.
TEMPERATURES TODAY SHOULD BE SEASONABLY WARM IF THERE ARE SOME
BREAKS IN THE RAIN AND CLOUD COVER. HOWEVER WITH THE UPPER TROUGH
OVER THE WRN GREAT LAKES TOMORROW...TEMPS WILL BE SEASONABLY COOL
WITH HIGHS ONLY IN THE LOWER TO MID 70S FOR MOST LOCATIONS.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
A SHORTWAVE WILL CONTINUE TO MOVE THROUGH THE REGION THURSDAY
NIGHT INTO FRIDAY...WITH SOME LINGERING SHOWERS AND THUNDERSTORMS.
WE WILL CONTINUE IN A GENERAL NW FLOW PATTERN FROM LATE IN THE
WEEK INTO THE WEEKEND. IN GENERAL...THERE WILL CONTINUE TO BE A
CHANCE OF SHOWERS AND THUNDERSTORMS FOR MOST OF THE PERIODS DURING
THE EXTENDED TIME FRAME. TEMPERATURES WILL CONTINUE TO BE QUITE
WARM...WITH 80S TO LOWER 90S THROUGHOUT THE PERIOD. NOT REALLY A
LOT OF FEATURES THROUGHOUT THE EXTENDED PERIOD...SO MAINLY LOOKING
AT SOME DIURNAL PRECIPITATION DUE TO SUBTLE FEATURES.
AVIATION.../06Z TAF ISSUANCE/
CONDITIONS DETERIORATING TO IFR IN AREAS OF HEAVY RAIN AND
THUNDERSTORMS. CONDITIONS AGAIN IMPROVING TO LOW-END VFR WITH
SCATTERED MVFR IN SHOWERS LATE WEDNESDAY MORNING...THEN VFR WITH
SCATTERED CLOUDS AND ISOLATED SHOWERS WEDNESDAY EVENING.
&&
.POINT TEMPS/POPS...
DLH 76 59 73 57 / 30 30 70 50
INL 79 56 72 55 / 20 40 70 40
BRD 83 62 77 59 / 50 20 60 20
HYR 83 59 78 58 / 50 20 60 50
ASX 80 59 76 59 / 50 20 60 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
742 PM CDT THU JUL 26 2012
.UPDATE...
ISSUED AT 730 PM CDT THU JUL 26 2012
HAVE EXPANDED THE MENTION OF ISOLATED SHOWERS AND THUNDERSTORMS
FURTHER SOUTH TOWARD CENTRAL PORTIONS OF THE CWA THIS EVENING. A
BROKEN LINE OF CONVECTION EXTENDING FROM NORTH CENTRAL MISSOURI
AND INTO CENTRAL ILLINOIS CONTINUES TO DRIFT SOUTHWARD...THOUGH
GIVEN INDICATIONS FROM HRRR MODEL OUTPUT AND THE LOSS OF DAYTIME
HEATING...THE EXPECTATION IS FOR THESE STORMS TO TAPER OFF THROUGH
THE LATE EVENING HOURS.
OTHERWISE...GOING FORECAST REMAINS ON TRACK WITH ONLY MINOR
CHANGES TO SHORT TERM TRENDS NEEDED FOR AREAS CO-LOCATED WITH
CONVECTION THIS EVENING.
PHILLIPSON
&&
.SYNOPSIS...
ISSUED AT 216 PM CDT THU JUL 26 2012
591DAM HIGH AT 500MB HAS SPLIT INTO TWO CENTERS...ONE LOCATED
ACROSS ARIZONA AND THE OTHER OVER LOUISIANA. IN BETWEEN...THE WELL
ADVERTISED TROF OF LOW PRESSURE EXTENDS FROM LAKE SUPERIOR TO
TEXAS.
OVERNIGHT MCS DISSIPATED ON SCHEDULE AS IT ENCOUNTERED THE REMAINING
RIDGE AXIS THAT AT 12Z WAS STILL POKING UP ALONG THE MISSISSIPPI
RIVER. THINNING CLOUD COVER AND VERY WARM 850MB TEMPERATURES ABOVE
20C RESULTED IN TEMPERATURES JUMPING BACK INTO THE 90S. TRUE SURFACE
COLD FRONT IS JUST NOW ENTERING THE NORTHWEST CORNER OF THE
CWA...BUT DEEP CONVECTION IS FIRING ALONG AND SOUTH OF THE OUTFLOW
BOUNDARY (SOUTHERN MISSOURI AND ILLINOIS).
CVKING
&&
.SHORT TERM...
ISSUED AT 216 PM CDT THU JUL 26 2012
(TONIGHT THROUGH SUNDAY)
COLD FRONT WILL MAKE STEADY PROGRESS SOUTH ACROSS THE CWA...WITH
FOCUS FOR DEEP CONVECTION QUICKLY MOVING SOUTH AND EAST OF THE CWA
THIS EVENING. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH DEWPOINTS
SLOW TO FALL BEHIND THE FRONT.
DEEP MIXING...ABOVE 800 MB...WILL RESULT IN ANOTHER HOT DAY ON
FRIDAY FOR MOST OF THE CWA. ONLY EXCEPTION IS FAR NORTH THAT WILL
ONLY BE MIXING MIDDLE/UPPER TEEN TEMPERATURES FROM 850MB RATHER THAN
+20C. WILL BE EXTENDING HEAT HEADLINES ONE MORE DAY WITH FORECAST
HIGHS IN THE UPPER 90S TO 100 DEGREES. DEEP MIXING WILL SEND
DEWPOINTS TANKING IN THE AFTERNOON DUE TO DRIER AIR ALOFT BEHIND THE
FRONT. HEAT INDEX VALUES WILL NOT REACH OFFICIAL CRITERIA...BUT DONT
WANT TO SEND THE WRONG MESSAGE...WE HAVE ONE MORE HOT DAY BEFORE
COOLER AIR FILTERS IN FOR SATURDAY.
AREA MAY EXPERIENCE RED FLAG CONDITIONS TOMORROW AFTERNOON...GIVEN
DROUGHT CONDITIONS...LOW RELATIVE HUMIDITY AND NORTHWEST WINDS. WILL
LET MIDSHIFT DETERMINE THE NEED FOR THE HEADLINE BASED ON LATEST
MODEL DATA AND RAINFALL REPORTS.
850MB THERMAL AXIS SHIFTS FURTHER TO THE WEST ON SATURDAY WITH
COOLER...YET STILL ABOVE NORMAL...TEMPERATURES EXPECTED. WITH DEEP
MIXING AND PLENTY OF SUNSHINE HAVE FORECAST HIGHS A DEGREE OR TWO
WARMER THAN THE WARMEST MET MOS.
PROSPECT FOR PRECIPITATION DOES INCREASE SATURDAY NIGHT AND SUNDAY
AS MODELS PORTRAY NOCTURNAL CONVECTION DEVELOPING ACROSS THE CENTRAL
PLAINS ON THE NOSE OF A LOW LEVEL JET. HAVE INCREASED CLOUD COVER
AND POPS SATURDAY NIGHT AND SUNDAY ACROSS NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS WHERE DECAYING CONVECTION WOULD PROPAGATE. IF
THIS OCCURS...TEMPERATURES MAY END UP COOLER THAN CURRENTLY FORECAST
FOR SUNDAY.
CVKING
&&
.LONG TERM...
ISSUED AT 216 PM CDT THU JUL 26 2012
(MONDAY THROUGH THURSDAY)
MODELS AGREE THAT AN ACTIVE NORTHWEST FLOW PATTERN WILL SET UP
ACROSS THE AREA FOR THE REMAINDER OF THE FORECAST AS THE UPPER LEVEL
RIDGE EXPANDS ACROSS THE ROCKIES/PLAINS AND A TROF DEEPENS OVER THE
EAST COAST. PINNING DOWN PRECIPITATION CHANCES IN THIS TYPE OF A
PATTERN IS VERY DIFFICULT DUE TO THE TIMING/TRACK OF WEAK
SHORTWAVES. TO ADD SALT TO THE WOUND...MODEL GUIDANCE HAS BEEN FAR
TOO ROBUST WITH PRECIPITATION DEVELOPMENT THE PAST FEW MONTHS DUE TO
THE EXTREME DROUGHT CONDITIONS. THEREFORE WILL REMAIN VERY
CONSERVATIVE IN FORECASTING PRECIPITATION IN THE EXTENDED PERIODS OF
THE FORECAST.
TEMPERATURES WILL REMAIN ABOVE NORMAL WITH EXACT VALUES BEING HIGHLY
DE PENDANT ON THE SURFACE FRONTAL POSITION...CLOUD COVER AND ANY
PRECIPITATION THAT IS OBSERVED. 850MB TEMPERATURES RANGE FROM THE
LOWER 20S ACROSS CENTRAL MISSOURI TO THE UPPER TEENS IN CENTRAL
ILLINOIS...WHICH SUPPORTS SURFACE TEMPERATURES NEAR 100 DEGREES IN
CENTRAL MISSOURI AND MIDDLE 90S IN CENTRAL ILLINOIS. DEWPOINTS MAY
POOL NEXT WEEK WITH THE CLOSE PROXIMITY OF THE FRONTAL POSITION AND
LEAD TO HEAT INDEX VALUES RISING BACK ABOVE 100 DEGREES AT TIMES.
CVKING
&&
.AVIATION...
ISSUED AT 611 PM CDT THU JUL 26 2012
HAVE ADDED A TEMPO THROUGH 01Z AT KUIN AS SCT THUNDERSTORM IS
MOVING TOWARD THE TERMINAL AT THIS TIME. THINK THESE STORMS WILL
DIMINISH IN THE NEXT COUPLE OF HOURS WITH THE LOSS OF DAYTIME
HEATING. OTHERWISE DRY AND VFR CONDITIONS ARE EXPECTED.
WINDS WILL BE LIGHT AND VARIABLE OR WESTERLY AROUND 6KTS THROUGH
12Z BEFORE A COLD FRONT MOVES ACROSS THE AREA. NORTHWESTERLY WINDS
OF 10-15KTS ARE EXPECTED THEREAFTER.
SPECIFICS FOR KSTL...DRY AND VFR CONDITIONS ARE EXPECTED. WINDS
WILL DECREASE TO AROUND 6KTS THIS EVENING BEFORE A COLD FROPA
VEERS THEM NORTHWESTERLY AROUND 12KTS AROUND 15Z.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR AUDRAIN MO-BOONE MO-
CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-MONITEAU MO-
MONTGOMERY MO-OSAGE MO-PIKE MO-REYNOLDS MO-ST. FRANCOIS MO-
STE. GENEVIEVE MO-WARREN MO-WASHINGTON MO.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT FRIDAY FOR ST. CHARLES MO-
ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR BOND IL-CALHOUN IL-
CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-
MARION IL-MONROE IL-MONTGOMERY IL-RANDOLPH IL-WASHINGTON IL.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT FRIDAY FOR MADISON IL-ST.
CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
903 PM CDT THU JUL 26 2012
.UPDATE...
UPDATED TO REMOVE ISOLATED THUNDERSTORMS.
&&
.AVIATION...
VISUAL FLIGHT RULES EXPECTED OVER WESTERN NEBRASKA THROUGH FRIDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 621 PM CDT THU JUL 26 2012/
UPDATE...
UPDATED FORECAST TO EXPAND THUNDERSTORM AREA.
PREV DISCUSSION... /ISSUED 406 PM CDT THU JUL 26 2012/
DISCUSSION...
A FAIRLY STRONG COLD FRONT ACROSS SD THIS AFTN IS PROGGED TO DROP
THROUGH SWRN NEB THIS EVENING AND BECOME STATIONARY ALONG THE KS
BORDER FRIDAY MORNING. THE FRONT...MARGINAL INSTABILITY...STRONG
SHEAR...30 TO 40 KTS OF BULK SHEAR RESULTING IN BULK RICHARDSON
NUMBER NEAR 25 AND SFC DEW POINTS IN THE LOWER 50S SUGGEST ISOLATED
HIGH BASED STORM COVERAGE SHOULD ANYTHING FORM. BOTH THE HRRR AND
RAP13 ARE VERY AMBITIOUS SHOWING SCATTERED STORM COVERAGE FROM 20Z
ONWARD.
THE FRONT WILL LIFT NORTH INTO NCNTL NEB FRIDAY AND ACT AS A FOCUS
FOR ISOLATED LATE AFTN AND EVENING HIGH BASED TSTMS GIVEN LOW SFC
DEW POINTS. TEMPS ALONG AND WEST OF HIGHWAY 83 SHOULD RECOVER WITH
HIGHS IN THE MID AND UPPER 90S.
INCREASING LOW LEVEL FLOW...DEEPENING LOW PRESSURE ACROSS THE NRN
HIGH PLAINS AND VERY DEEP MOISTURE ABOVE 700 MB IS EXPECTED TO
PRODUCE A ROUND OF SCATTERED HIGH BASED TSTMS...POSSIBLY PRODUCING
WIND DAMAGE AS THEY MOVE EAST ACROSS THE FCST AREA FRIDAY NIGHT
INTO SATURDAY MORNING. THIS AREA OF STORMS MOVES TO NEAR KOMA BY
12Z SATURDAY AND THE WARM FRONT ADVANCES NORTH AND EAST TO NEAR
KONL/KYKN SATURDAY AFTERNOON. HIGHS SATURDAY SHOULD BE ABLE TO
REACH 100F AS H10-5 THICKNESSES RISE TO NEAR 590 DM. MORE ISOLATED
DIURNALLY DRIVEN HIGH BASED TSTMS ARE EXPECTED TO DEVELOP LATE SATURDAY.
ANOTHER WEAK BACK DOOR COLD FRONT WILL MOVE THROUGH SATURDAY
NIGHT. THIS FRONT WOULD APPEAR TO WASH OUT ACROSS SRN NEB SUNDAY.
BY NOW A HEAT LOW HAS ESTABLISHED ITSELF ACROSS WRN KS/ERN COLO.
THIS LOW COULD STILL PRODUCE TEMPS NEAR 100F AS BOTH THE NAM AND
GEM SHOW H10-5 THICKNESSES APPROACHING 590 DM ACROSS WRN NEB. THE
GENERAL CONSENSUS AMONG THE MODELS WAS FOR ANOTHER UPPER LEVEL
DISTURBANCE TO MOVE THROUGH LATE SUNDAY SUNDAY NIGHT.
MONDAY THROUGH THURSDAY...
THE DROUGHT RIDGE IS FCST BY ALL MODELS TO REMAIN STATIONARY AND
CENTER OVER ERN NM/NW TX. THIS COULD PLACE THE FCST AREA IN THE
RING OF FIRE PROVIDED AMPLE MOISTURE IS AVAILABLE. THE ECM AND GFS
850-300MB MOISTURE SUPPORT THIS BUT FCST QPF IN BOTH MODELS IS
DRY. SO DRY WEATHER IS EXPECTED WITH HIGHS AT LEAST IN THE 90S. H7
TEMPS ARE EXPECTED TO RUN 10C TO 14C WHICH SHOULD PRODUCE UPPER
90S. NOTE THE EXTREME DROUGHT CONDITIONS MAY SUPPORT HIGHS AROUND
100 BUT NOT NEARLY AS WARM AS WE SAW EARLIER THIS MONTH.
FIRE WEATHER...
ALL THUNDERSTORM ACTIVITY WILL BE CLOSELY MONITORED DURING THE
NEXT 7 DAYS FOR SIGNS OF DRY LIGHTNING AND POTENTIAL WILD FIRES.
STORM COVERAGE IS EXPECTED TO BE LESS THAN 25 PERCENT IN ANY ONE
PARTICULAR FIRE WEATHER ZONE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...POWER/CDC
AVIATION...POWER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
621 PM CDT THU JUL 26 2012
.UPDATE...
UPDATED FORECAST TO EXPAND THUNDERSTORM AREA.
&&
.PREV DISCUSSION... /ISSUED 406 PM CDT THU JUL 26 2012/
DISCUSSION...
A FAIRLY STRONG COLD FRONT ACROSS SD THIS AFTN IS PROGGED TO DROP
THROUGH SWRN NEB THIS EVENING AND BECOME STATIONARY ALONG THE KS
BORDER FRIDAY MORNING. THE FRONT...MARGINAL INSTABILITY...STRONG
SHEAR...30 TO 40 KTS OF BULK SHEAR RESULTING IN BULK RICHARDSON
NUMBER NEAR 25 AND SFC DEW POINTS IN THE LOWER 50S SUGGEST ISOLATED
HIGH BASED STORM COVERAGE SHOULD ANYTHING FORM. BOTH THE HRRR AND
RAP13 ARE VERY AMBITIOUS SHOWING SCATTERED STORM COVERAGE FROM 20Z
ONWARD.
THE FRONT WILL LIFT NORTH INTO NCNTL NEB FRIDAY AND ACT AS A FOCUS
FOR ISOLATED LATE AFTN AND EVENING HIGH BASED TSTMS GIVEN LOW SFC
DEW POINTS. TEMPS ALONG AND WEST OF HIGHWAY 83 SHOULD RECOVER WITH
HIGHS IN THE MID AND UPPER 90S.
INCREASING LOW LEVEL FLOW...DEEPENING LOW PRESSURE ACROSS THE NRN
HIGH PLAINS AND VERY DEEP MOISTURE ABOVE 700 MB IS EXPECTED TO
PRODUCE A ROUND OF SCATTERED HIGH BASED TSTMS...POSSIBLY PRODUCING
WIND DAMAGE AS THEY MOVE EAST ACROSS THE FCST AREA FRIDAY NIGHT
INTO SATURDAY MORNING. THIS AREA OF STORMS MOVES TO NEAR KOMA BY
12Z SATURDAY AND THE WARM FRONT ADVANCES NORTH AND EAST TO NEAR
KONL/KYKN SATURDAY AFTERNOON. HIGHS SATURDAY SHOULD BE ABLE TO
REACH 100F AS H10-5 THICKNESSES RISE TO NEAR 590 DM. MORE ISOLATED
DIURNALLY DRIVEN HIGH BASED TSTMS ARE EXPECTED TO DEVELOP LATE SATURDAY.
ANOTHER WEAK BACK DOOR COLD FRONT WILL MOVE THROUGH SATURDAY
NIGHT. THIS FRONT WOULD APPEAR TO WASH OUT ACROSS SRN NEB SUNDAY.
BY NOW A HEAT LOW HAS ESTABLISHED ITSELF ACROSS WRN KS/ERN COLO.
THIS LOW COULD STILL PRODUCE TEMPS NEAR 100F AS BOTH THE NAM AND
GEM SHOW H10-5 THICKNESSES APPROACHING 590 DM ACROSS WRN NEB. THE
GENERAL CONSENSUS AMONG THE MODELS WAS FOR ANOTHER UPPER LEVEL
DISTURBANCE TO MOVE THROUGH LATE SUNDAY SUNDAY NIGHT.
MONDAY THROUGH THURSDAY...
THE DROUGHT RIDGE IS FCST BY ALL MODELS TO REMAIN STATIONARY AND
CENTER OVER ERN NM/NW TX. THIS COULD PLACE THE FCST AREA IN THE
RING OF FIRE PROVIDED AMPLE MOISTURE IS AVAILABLE. THE ECM AND GFS
850-300MB MOISTURE SUPPORT THIS BUT FCST QPF IN BOTH MODELS IS
DRY. SO DRY WEATHER IS EXPECTED WITH HIGHS 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...POWER/CDC
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
614 PM CDT THU JUL 26 2012
.AVIATION...
00Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDS ARE EXPECTED THROUGH THE PERIOD. SCT CU AT OMA/LNK WILL
QUICKLY DISSIPATE THIS EVNG LEAVING CLR SKIES FOR ALL 3 TAF SITES
OVER THE NEXT 24 HOURS. OTHERWISE WINDS WILL BE GENERALLY LIGHT AND
FROM THE NORTH AND NORTHWEST THROUGH THE PERIOD.
BOUSTEAD
&&
.DISCUSSION...
SMALL CHANCE FOR PRECIPITATION TONIGHT...THEN THUNDERSTORM CHANCES
FRIDAY NIGHT THROUGH MONDAY...ARE THE PRIMARY FORECAST CONCERNS.
SECONDARY COOL FRONT WAS DROPPING THROUGH THE CWA THIS AFTERNOON.
TEMPERATURES WERE SIMILAR ON BOTH SIDES OF THE BOUNDARY...BUT DEW
POINTS DRIED CONSIDERABLY BEHIND THE FRONT. DEW POINTS WERE IN THE
THE 50S IN NORTHEAST NEBRASKA AS OF 2 PM...WHILE SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA HAD DEW POINTS BETWEEN 65 AND 70. INSTABILITY
WAS INCREASING IN THIS AREA WITH MOST UNSTABLE CAPE VALUES TOPPING
3000 J/KG. LOW LEVEL CONVERGENCE WAS RATHER WEEK AS WINDS ONLY
TURNED FROM WEST TO NORTHWEST AHEAD AND BEHIND FRONT. AND MID
LEVEL LAPSE RATES WERE RATHER TIMID AS WELL. STILL CUMULUS FIELD
WAS BUBBLING UP IN CYCLONIC FLOW IN EAST CENTRAL NEBRASKA AND WEST
CENTRAL IOWA. NAM...GFS AND HRRR ALL SUGGEST SOME CONVECTION WILL
FIRE IN THE UNSTABLE AIR OVER SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA LATE THIS AFTERNOON AND EVENING. GIVEN INSTABILITY AND WEAK
CONVERGENCE ALONG FRONT...PLUS THE FACT THAT RETURNS ARE SHOWING
UP ON RADAR...WILL INSERT ISOLATED STORMS THIS AFTERNOON AND
EVENING IN THOSE AREAS.
STORMS SHOULD MOVE OUT OR DISSIPATE RATHER QUICKLY BY
SUNSET...LEAVING MOSTLY CLEAR SKIES AND DIMINISHING WINDS AS
SURFACE HIGH PRESSURE SETTLES IN OVERNIGHT. THAT HIGH AND A
REDUCTION IN 850 TEMPS BY 5C OR SO WILL LEAD TO COOLER
TEMPERATURES FRIDAY. HAVE HIGHS FROM THE MIDDLE 80S NORTH TO NEAR
90 SOUTH FRIDAY AFTERNOON WITH LIGHT NORTH OR NORTHEAST WINDS.
AS THE HIGH SHIFTS EAST FRIDAY NIGHT...RETURN FLOW BEGINS AS
SHORTWAVE MOVES OFF THE HIGH PLAINS INTO THE REGION. MODELS HAVE
BEEN ADVERTISING THIS THE LAST SEVERAL DAYS...AND ARE NOW CONVERGING
ON A TRACK THROUGH SOUTH DAKOTA AND INTO SOUTHEAST SOUTH DAKOTA BY
12Z SATURDAY. THIS WILL SHIFT AXIS OF ASSOCIATED PRECIPITATION NORTH
OF OUR CURRENT FORECAST...WITH HIGHEST POPS ALONG THE SOUTH DAKOTA
BORDER. WILL MAINTAIN SMALL POPS SOUTHWARD AT LEAST TO INTERSTATE 80
LATE FRIDAY NIGHT AND SATURDAY MORNING WHERE HIGHER THETA-E AIR WILL
RIDE NORTH. AREA SHOULD LIFT TO THE NORTHEAST SATURDAY AFTERNOON AND
WILL MAINTAIN SMALL POPS IN OUR FAR NORTHEAST THEN.
A SIMILAR SITUATION WILL OCCUR SATURDAY NIGHT INTO SUNDAY AS ANOTHER
SHORTWAVE ROLLS THROUGH THE NORTHERN PLAINS. BOTH GFS AND ECMWF SHOW
THIS WAVE A BIT FARTHER NORTH THAN FRIDAY NIGHT WAVE...BUT
MOISTURE...LOW LEVEL JET AND ELEVATED INSTABILITY WILL ALL BE MORE
CONDUCIVE FOR SCATTERED OVERNIGHT CONVECTION. THUS WILL KEEP OUR
SMALL POPS FOR MOST OF THE CWA WITH HIGHEST CHANCES AGAIN IN THE
NORTH AND NORTHEAST.
SURFACE FRONT WILL TRAIL THIS SECOND WAVE AND SETTLE ACROSS THE CWA
SUNDAY NIGHT AND MONDAY. GFS AND ECMWF TRIGGER PRECIPITATION ALONG
THIS BOUNDARY AS YET ANOTHER SHORTWAVE DROPS THROUGH NORTHWEST FLOW
ALOFT...BUT EACH MODEL HAS A SLIGHTLY DIFFERENT TRACK.
WILL KEEP OUR DRY AND WARMER FORECAST GOING THROUGH MID WEEK AS
UPPER RIDGE TRIES TO BUILD BACK INTO THE REGION. MODELS ARE A LITTLE
LESS BULLISH ON BRINGING THIS INTO THE PLAINS...POSSIBLY ALLOWING
MORE SHORTWAVES TO DROP INTO THE REGION BRINGING SPORADIC PRECIP
CHANCES.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
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
&&
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
A COLD FRONT FROM NORTHEAST INTO SOUTH CENTRAL NEBRASKA AT 18Z
WILL TRACK ACROSS THE AREA THIS AFTERNOON AND THIS EVENING.
SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE VICINITY OF
THE FRONT THIS AFTERNOON AND CONTINUE INTO THE EVENING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR NEZ044-
045-050>053-065>068-078-088>093.
IA...EXCESSIVE HEAT WARNING UNTIL 8 PM CDT THIS EVENING FOR IAZ055-
056-069-079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
253 PM MDT WED JUL 25 2012
.DISCUSSION...
...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
&&
.AVIATION...
18Z TAF CYCLE
OVERALL...EXPECTING LESS TS AND SH ACTIVITY WESTERN AREAS VERSUS
YESTERDAY AND ALREADY SEEING A SLOWER START TO THE DVLP.
HOWEVER...EXPECTING MORE ACTIVE TS/SH CENTRAL MTNS
EASTWARD...ESPECIALLY THE EASTERN PLAINS. A MODERATE BACK DOOR
COLD FRONT WILL PROVIDE THE FOCUSING MECHANISM FOR THIS ACTIVITY
IN THE EAST TODAY. THUS...HAVE GONE BULLISH WITH SOME SORT OF
PRECIP MENTION AT LVS...TCC AND TO LESSER EXTENT ROW. BASED ON AN
OVERALL NORTHERLY STEERING FLOW...CANT RULE OUT ABQ AND SAF AS
WELL AS GUP. NOT EXPECTING SH/TS AFFECTS AT FMN. GUSTY OUTFLOW
WINDS WILL BE THE MAIN IMPACT CENTRAL AND WESTERN TERMINAL SITES.
THINKING THE POSSIBILITY OF MVFR CIG/VIS FOR SHORT DURATION
POSSIBLE ACROSS THE EAST ALTHOUGH NOT REFLECTIVE IN THE TAF/S.
WILL UPDATE ACCORDINGLY AS HEAVIER PRECIP STORMS DVLP. 50
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 62 93 64 92 / 10 20 30 30
DULCE........................... 49 89 49 85 / 20 30 40 40
CUBA............................ 54 86 55 83 / 20 30 40 40
GALLUP.......................... 54 88 55 85 / 20 20 30 40
EL MORRO........................ 52 84 51 80 / 20 30 40 50
GRANTS.......................... 54 87 54 83 / 20 30 40 40
QUEMADO......................... 56 85 56 82 / 40 40 40 50
GLENWOOD........................ 58 92 58 92 / 30 20 30 40
CHAMA........................... 48 83 50 80 / 30 40 50 50
LOS ALAMOS...................... 59 85 60 84 / 30 60 40 40
PECOS........................... 57 81 57 81 / 40 60 40 40
CERRO/QUESTA.................... 54 79 55 80 / 30 50 40 50
RED RIVER....................... 48 69 47 71 / 40 60 40 60
ANGEL FIRE...................... 44 72 45 73 / 40 60 40 60
TAOS............................ 51 86 49 86 / 30 40 40 40
MORA............................ 55 78 54 79 / 40 50 50 50
ESPANOLA........................ 59 92 58 91 / 30 40 30 30
SANTA FE........................ 60 83 60 82 / 40 50 40 40
SANTA FE AIRPORT................ 61 87 60 87 / 30 40 40 30
ALBUQUERQUE FOOTHILLS........... 64 90 65 88 / 30 40 50 40
ALBUQUERQUE HEIGHTS............. 65 91 68 89 / 30 30 40 30
ALBUQUERQUE VALLEY.............. 63 93 66 91 / 20 30 40 30
ALBUQUERQUE WEST MESA........... 67 93 66 90 / 20 30 40 30
LOS LUNAS....................... 63 92 64 91 / 20 30 40 30
RIO RANCHO...................... 67 92 67 90 / 20 30 40 30
SOCORRO......................... 66 94 67 94 / 20 30 40 30
SANDIA PARK/CEDAR CREST......... 61 84 61 84 / 30 60 50 50
TIJERAS......................... 59 88 61 88 / 30 50 50 40
MORIARTY/ESTANCIA............... 58 87 57 85 / 40 50 50 40
CLINES CORNERS.................. 57 83 58 82 / 40 60 50 50
GRAN QUIVIRA.................... 60 86 61 84 / 40 40 50 50
CARRIZOZO....................... 61 89 62 88 / 30 40 40 50
RUIDOSO......................... 59 80 58 77 / 40 50 50 50
CAPULIN......................... 59 80 60 83 / 50 60 30 30
RATON........................... 57 87 57 90 / 50 60 30 30
SPRINGER........................ 60 86 60 88 / 40 40 30 30
LAS VEGAS....................... 55 82 55 83 / 40 60 40 50
CLAYTON......................... 67 88 66 92 / 50 30 20 20
ROY............................. 65 85 64 85 / 50 40 30 20
CONCHAS......................... 69 93 69 94 / 50 40 30 30
SANTA ROSA...................... 70 93 69 91 / 40 40 40 30
TUCUMCARI....................... 70 95 72 96 / 40 40 40 30
CLOVIS.......................... 70 91 69 90 / 40 40 40 30
PORTALES........................ 72 93 70 92 / 40 40 40 30
FORT SUMNER..................... 74 93 72 93 / 40 40 40 30
ROSWELL......................... 70 96 71 93 / 40 40 30 30
PICACHO......................... 66 88 65 84 / 40 40 40 30
ELK............................. 60 83 59 79 / 40 40 50 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
GUYER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
158 AM EDT WED JUL 25 2012
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS THE MID ATLANTIC
REGION THROUGH WEDNESDAY...PRODUCING WIDESPREAD THUNDERSTORMS THIS
AFTERNOON AND EVENING...AND SCATTERED STORMS WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM TUESDAY...
THE MCS FROM EARLIER THIS EVENING IS OFFSHORE AND SOUTH OF THE
CWA...WITH STRONG SUBSIDENCE AND LOW LEVEL STABILIZATION IN ITS WAKE
EVIDENT IN THE 00Z KGSO/KMHX RAOBS. STABILIZATION HAS BEEN FURTHER
AIDED BY A BRIEF PERIOD OF STRONGER WESTERLY FLOW BETWEEN A
MESO-HIGH OVER NORTHEAST TN AND THE PIEDMONT TROUGH...WHICH APPEARS
TO HAVE HELPED DROP DEWPOINTS INTO THE MID 60S OVER THE WESTERN
PIEDMONT. THERE IS STILL SOME ELEVATED INSTABILITY ABOVE THE
SUBSIDENCE INVERSION WITH MUCAPE LIKELY STILL AT OR ABOVE 1000
J/KG...BUT PARCELS WOULD HAVE TO LIFT FROM NEAR 800 MILLIBARS TO
TAP THIS ENERGY. THE 850-700MB FLOW OBSERVED AT KGSO WAS IN EXCESS
OF 50 KNOTS...WHICH IS HIGHER THAN ANY OTHER NEARBY SITE BUT SEEMS
REASONABLE GIVEN THE INTENSITY OF THE DEPARTING MCS. NONE OF THE
MODELS WERE FORECASTING SUCH A STRONG LOW LEVEL JET...BUT THE FLOW
IS GENERALLY DIVERGENT AND SHOULD NOT CONTRIBUTE TO LIFT ON ITS OWN.
THERE IS ANOTHER REMNANT MCV TRACKING SOUTHEAST ACROSS SOUTHERN
OHIO...WHICH THE RAP BRINGS INTO THE NORTHWEST AROUND 09Z. WE ARE
NOT COMPLETELY COMFORTABLE REMOVING POPS FROM THE FORECAST GIVEN
THE AFOREMENTIONED FORCING/ELEVATED INSTABILITY AND POOR MODEL
PERFORMANCE...SO WE WILL LEAVE A SLIGHT CHANCE OF A THUNDERSTORM
OVER THE WESTERN CWA. CLEARING IS FINALLY OCCURRING BEHIND THE
MCS...BUT THIN DEBRIS CLOUDINESS WILL DRIFT OVERHEAD AT TIMES
OVERNIGHT...AND GIVEN THAT DEWPOINTS HAVE FALLEN OVER THE WESTERN
PIEDMONT...WE WILL TRIM 2 TO 3 DEGREES OFF FORECAST LOWS
EVERYWHERE EXCEPT THE SOUTHEAST AREAS.
WEDNESDAY...
NORTHWEST FLOW WITH WEAK EMBEDDED SHORT WAVES EXPECTED TO
CONTINUE TOMORROW...BUT THIS FLOW WILL WEAKEN WITH A CUTOFF TROUGH
MOVING EAST OFF THE NEW ENGLAND COAST. IN TERMS OF THE AIR MASS
AND THERMODYNAMIC PROFILE...LITTLE CHANGE IS EXPECTED...ALTHOUGH
THE DAY WILL START OFF WITH MORE CLOUDINESS THAN TODAY. EXPECT
ADDITIONAL SCATTERED AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS... BUT WITH WEAKER MID AND UPPER FLOW AND
SHEAR...EXPECT COVERAGE TO BE REDUCED COMPARED TO TODAY. SEVERE
STORM IMPACTS WILL ONCE AGAIN FAVOR DAMAGING WINDS GUSTS MORE THAN
HAIL.
WEDNESDAY CONVECTION EXPECTED TO END BY LATE EVENING FOLLOWED BY
PARTLY CLOUDY OVERNIGHT PERIOD.
HIGHS WEDNESDAY 89 NORTHWEST TO NEAR 95 SOUTHWEST...AND LOWS
WEDNESDAY NIGHT 71 NORTHEAST TO NEAR 75 EXTREME SOUTH.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 1225 PM TUESDAY...
MIGRATORY LOW LEVEL RIDGING MOVING EAST ACROSS THE AREA WILL PRODUCE
SOUTHWEST TO WESTERLY FLOW AND INDUCE A HEAT RIDGE REFLECTED IN LOW
LEVEL THICKNESSES IN EXCESS OF 1440 METERS AND 850 MILLIBAR
TEMPERATURES OF 22 TO 24C. CORRESPONDING SURFACE HIGHS EXPECTED
TO REACH UPPER 90S... POTENTIALLY SOME VERY LOW TRIPLE DIGITS.
THESE ARE BELOW RECORDS FOR THE DATES...WITH THE EXCEPTION OF THU
AT RDU. SEE CLIMATE SECTION BELOW. HIGH INSTABILITY WITH NO
FORCING MECHANISM WILL FAVOR CLIMATOLOGICAL DIURNAL CONVECTION IN
THE WESTERN PIEDMONT AND IN THE COASTAL PLAIN DUE TO DIFFERENTIAL
HEATING AND SEA BREEZE PENETRATION...RESPECTIVELY.
TROUGH APPROACHING FROM THE WEST AND AN ASSOCIATED SURFACE FRONT
WILL APPROACH FROM THE NORTHWEST FRIDAY. FRONTAL PASSAGE WILL BE
AFTER MAXIMUM HEATING FRIDAY...WITH HIGHS REACHING UPPER 90S...AGAIN
WITH POTENTIALLY A STRAY 100 DEGREE READING. WILL INCREASE THE
CHANCE OF SHOWERS LATER FRIDAY NIGHT DUE TO A LITTLE QUICKER
FRONTAL PASSAGE AS DEPICTED ON LATEST MODEL RUNS. MILD AND MUGGY
WITH LOWS WITHIN A DEGREE OR TWO OF MIDDLE 70S BOTH NIGHTS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 1225 PM TUESDAY...
MEDIUM RANGE NWP GUIDANCE IS IN GOOD AGREEMENT REGARDING THE GRADUAL
ESTABLISHMENT OF A MEAN TROUGH ALOFT OVER THE EAST COAST THIS
WEEKEND THROUGH EARLY NEXT WEEK. AS THIS TROF BECOMES
ESTABLISHED...THE SURFACE COLD FRONT EARLY THIS WEEKEND WILL PUSH
THROUGH CENTRAL NORTH CAROLINA ON SATURDAY...WITH RELATIVELY
COOLER AND DRIER (AND MORE STABLE) HIGH PRESSURE BUILDING ACROSS
THE APPALACHIANS SUNDAY THROUGH TUESDAY. WITH THE DRIER NORTHWEST
FLOW REGIME IN PLACE...ONLY SLIGHT CHANCE POPS EXPECTED SUNDAY AND
MONDAY...WHILE A POTENTIAL SHORT WAVE DIGGING INTO THE EAST COAST
TROUGH WILL INCREASE CHANCES ON TUESDAY.
HIGH TEMPERATURES WILL BE NEAR NORMAL...IN THE 90 TO 95 DEGREE RANGE
SATURDAY THROUGH MONDAY...POTENTIALLY A LITTLE COOLER TUESDAY IF WE
GET A REINFORCING SHORT WAVE DEEPENING THE MEAN TROUGH.
PERSISTENCE LOWS EXPECTED THROUGH THE PERIOD...BASICALLY 70 TO 74.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 155 AM...
THUNDERSTORMS CROSSING THE VIRGINIA MOUNTAINS AT THIS TIME
APPROACHING MUCH MORE STABLE NEAR SURFACE AIR OVER NORTH CAROLINA.
HOWEVER INSTABILITY ALOFT MAY ALLOW THESE STORMS TO PERSIST INTO
THE TRIAD... ARRIVING BEFORE 4 AM. OTHERWISE A LIGHT BREEZE TONIGHT
WITH LOCALIZED MVFR FOG.
OTHER THAN THE ABOVE MENTIONED THUNDERSTORM RISK THIS MORNING...
CONVECTION SHOULD BE LESS WIDESPREAD AND LESS INTENSE THAN
EXPERIENCED TUESDAY. BEST... THOUGH LIMITED... AFTERNOON COVERAGE
IS FORECAST SOUTH OF GREENSBORO... WITH SLIGHT CHANCES OR LESS
ELSEWHERE.
EXPECT A DAILY THREAT FOR ISOLATED TO SCATTERED CONVECTION IN THE
AFTERNOON AND EVENING HOURS INTO SUNDAY WITH ASSOCIATED SUB VFR
CEILINGS AND VISIBILITY. SUB VFR FOG AND/OR LOW STRATUS POSSIBLE
EACH MORNING.... ESPECIALLY FOR LOCATIONS THAT RECEIVE
SUBSTANTIAL RAIN FROM THE PREVIOUS DAY/EVENING. OTHERWISE....
EXPECT VFR CONDITIONS WILL CONTINUE.
&&
.CLIMATE...
THE FOLLOWING ARE THE RECORD HIGH TEMPERATURES FOR THE 26TH AND 27TH:
RDU GSO FAY
THU (26TH): 101 IN 2005 102 IN 1914 104 IN 1940
FRI (27TH): 104 IN 1940 104 IN 1914 106 IN 1940
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
NEAR TERM...SMITH/NMP
SHORT TERM...MLM
LONG TERM...MLM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
827 PM CDT THU JUL 26 2012
.DISCUSSION...
THE MAIN CHALLENGE OVERNIGHT WILL BE TEMPS AND POSSIBLE PATCHY
FOG. THE UPPER LOW WILL CONTINUE TO MOVE OUT OF THE REGION
OVERNIGHT...AND SFC HIGH PRESSURE WILL BUILD INTO THE REGION.
DEWPOINTS SHOULD FALL INTO THE LOW/MID 50S FOR MOST AREAS WITH
SOME COOLER POCKETS POSSIBLE. THE LATEST HRRR DOES HAVE SOME LOWER
VSBYS IN PATCHY FOG LATER TONIGHT FOR MOST AREAS...BUT FEEL THAT
ND COUNTIES AT MOST RISK...SO WILL ADD SOME PATCHY BR LATE ALONG
AND WEST OF THE VALLEY 9-12Z. OTHERWISE...THE REST OF THE FORECAST
LOOKS GOOD WITH MINIMAL CHANGE NEEDED.
&&
.AVIATION...
CONDITIONS WILL BECOME VFR LATER THIS EVENING IN ALL AREAS AS THE
UPPER LOW PULLS AWAY. WINDS WILL ALSO DECREASE WITH HIGH PRESSURE
BUILDING IN OVERNIGHT. THERE COULD BE SOME PATCHY BR LATE
TONIGHT...BUT DID NOT MENTION SINCE IT SHOULD BE VERY PATCHY...BUT
SOMETHING TO MONITOR.
&&
.PREV DISCUSSION... /ISSUED 246 PM CDT THU JUL 26 2012/
SHORT TERM...
CHALLENGES WILL BE HOW FAST CLOUDS AND PCPN CLEAR OUT OF THE FA
TONIGHT AND THEN PCPN CHANCES AGAIN BY LATER IN THE WEEKEND. WILL
STICK A LITTLE CLOSER TO FORECAST CONTINUITY FOR THE SHORT TERM.
TONIGHT...THE UPPER LOW IS SPINNING INTO NORTHWEST MN THIS
AFTERNOON AND IT IS STILL EXPECTED TO PUSH TO NEAR KDLH BY 00Z
FRI. DECENT AMOUNT OF CLOUD COVER HAS FORMED OVER THE ENTIRE FA
WITH A CLEARING LINE EVIDENT UPSTREAM ACROSS SOUTHERN CANADA. WITH
THE MAIN LIFT EXITING THE AREA THIS EVENING COMBINED WITH THE LOSS
OF DAYTIME HEATING SHOULD BRING AN END TO THE SHOWERS/ISOLATED
THUNDER BY MID TO LATE EVENING. QUESTION THEN IS HOW FAST THE
CLOUDS CLEAR OUT. MODELS ARE PRETTY CONSISTENT IN CLEARING THINGS
OUT BUT HAVE LEFT IN SOME HIGHER CLOUD AMOUNTS TO BLEND WITH
EASTERN BORDER OFFICES. WITH THINGS CLEARING OUT AND WINDS DYING
OFF LATE THERE COULD BE SOME PATCHY FOG. HOWEVER IT HAS STILL BEEN
DRY ACROSS A GOOD PART OF THE FA AND NOT CONFIDENT ENOUGH TO PUT
ANY IN AT THIS POINT. WILL LET LATER SHIFTS WATCH HOW THINGS
PROGRESS AND ADD IF THEY DECIDE TO.
FRI-SUN...SFC HIGH PRESSURE BUILDS INTO THE FA ON FRI WITH LIGHT
WINDS AND A GOOD AMOUNT OF SUN EXPECTED. HIGHS SHOULD WARM BACK TO
AROUND NORMAL ONCE AGAIN. WINDS LOOK TO STAY PRETTY LIGHT INTO
FRIDAY NIGHT BUT THE WESTERN FA MAY SEE SOME LIGHT RETURN FLOW.
ANY WEAK LOW LEVEL JET ENERGY APPEARS TO STAY TO THE WEST OF THE
FA. BY SAT THE MAIN INSTABILITY AXIS SHOULD CONTINUE TO REMAIN TO
THE WEST OF THE FA BUT WILL LEAVE SOME ISOLATED CHANCES IN THE FAR
WEST SINCE THEY WERE ALREADY THERE. LOW LEVEL JET AND WARM
ADVECTION MAY HELP SUSTAIN A TSTM COMPLEX TO THE SOUTH OF THE
AREA SAT NIGHT. THERE COULD ALSO BE SOME UPPER LEVEL SUPPORT
ACROSS THE NORTHERN FA WHICH MAY RESULT IN LITTLE IF ANYTHING IN
BETWEEN. SFC BOUNDARY SHOULD BE OVER THE FA ON SUN AND WITH DECENT
HEATING AND RISING SFC DEW POINTS...GOOD INSTABILITY SHOULD
DEVELOP DURING THE DAY. THIS MAY BE THE DAY WITH THE BEST CHANCE
FOR MORE SHOWERS AND TSTMS. PRECIPITABLE WATER VALUES RISE TO
AROUND 1.5 INCHES TOO SO MUCH RICHER MOISTURE SHOULD BE AVAILABLE.
LONG TERM (SUN NIGHT-THU)...
REGION WILL REMAIN IN ELEVATED NW FLOW PATTERN THROUGH THE LONG
RANGE PERIOD. MAIN CHALLENGE WILL BE TIMING OF WEAK IMPULSES
ROUNDING RIDGE PROVIDING LIGHT PCPN CHANCES. AS EXPECTED MODELS
DIFFER ON TIMING OF ANY WEAK FEATURES MAKING ANY FINE TUNING OF POPS
DIFFICULT. FOR THIS WILL MAINTAIN NATIONAL GUIDANCE LOW POPS ON AND
OFF THROUGH THE PERIOD. TEMPERATURES SHOULD RANGE AT OR ABOVE
SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
DK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
420 PM EDT WED JUL 25 2012
.SYNOPSIS...
A STRONG WARM FRONT LIFTING THROUGH INDIANA AND KENTUCKY WILL
CONTINUE NORTH AND EASTWARD TONIGHT ALLOWING VERY WARM AIR OVER
THE CENTRAL MISSISSIPPI VALLEY TO SPREAD INTO THE AREA TONIGHT.
THIS WARM FRONT MAY BE ACCOMPANIED BY A FEW THUNDERSTORMS DURING
THE NIGHT AS IT CROSSES THE AREA...BUT THE BIGGER STORY WILL COME
ON THURSDAY WHEN HEAT BUILDS AHEAD OF A COLD FRONT SAGGING INTO
THE GREAT LAKES. HEAT INDICES IN EXCESS OF 100 DEGREES ARE LIKELY
FOR MUCH OF THE AREA...AND AS THE FRONT ARRIVES AT PEAK
HEATING...NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
THE AREA...SOME WHICH ARE LIKELY TO BE SEVERE. THE FRONT WILL
CONTINUE A VERY SLOW PROGRESSION SOUTH AND EAST ON FRIDAY WITH
LINGERING THREATS FOR STORMS...BEFORE PUSHING OUT OF THE AREA BY
SATURDAY. THIS SHOULD BRING SLIGHTLY COOLER TEMPERATURES AND LESS
HUMIDITY TO THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
PLAN TO ALLOW EXCESSIVE HEAT WARNING AND HEAT ADVISORIES EXPIRE AS
SCHEDULED AT 8 PM...EXCEPT FOR HAMILTON/MONTGOMERY COUNTIES WHERE
WE WILL CONTINUE WITH HEAT HEADLINES THROUGH THE NIGHT DUE TO
LOCAL EXCESSIVE HEAT WARNING CRITERIA.
STRONG WARM FRONT CURRENTLY DRAPED NW-SE ACROSS INDIANA AND
KENTUCKY TO CONTINUE TO PUSH EAST THIS EVENING AND HAS SUBSTANTIAL
BOUNDARY LAYER MOISTURE POOLED ALONG THIS FEATURE VIA CONVERGENCE.
DEW POINTS IN THE SULTRY MID 70S ALLOWING FOR THE EXCESSIVE HEAT
WARNING THIS EVENING IN THE SOUTHWEST. A BIG AIRMASS CHANGE TO
THAT OVER CNTL OH WHERE DEW POINTS STILL AROUND 60 WITH TEMPS ONLY
IN THE 80S.
CURRENTLY WATCHING DEVELOPING CUMULUS FIELD ALONG/BEHIND THE WARM
FRONT WHERE HRRR RUNS HAVE BEEN CONSISTENT IN ADVERTISING SCT TO
NUMEROUS STORMS BETWEEN 4 PM AND 8 PM ON THE FRONT...AND PUSHING
EAST THROUGH THE WFO ILN FORECAST AREA. IF THIS OCCURS...THERE WILL
BE A SEVERE THREAT GIVEN EXPLOSIVE CAPE IN EXCESS OF 3000 J/KG
ALONG THE FRONT AND MARGINAL SUPERCELLULAR SHEAR AROUND 25-30KTS WHEN
CONSIDERING DEEPER TROPOSPHERIC FLOW ALONG AND ON THE COOL SIDE OF
THE WARM FRONT. HOWEVER...UNDER SHORTWAVE RIDGING AND NO APPARENT S/W
ON WV IMAGERY...VERY LITTLE BACKGROUND/SYNOPTIC FORCING FOR
ASCENT. FEELING IS CURRENTLY THAT WE WILL DEVELOP STORM OR TWO IN
THE MOST CONVERGENT AREAS ALONG THE FRONT AS HEATING PUSHES TEMPS
PAST 100 DEGREES TO OUR WEST AND CAP IS LOCALLY BROKEN. MAY HAVE
AN ISOLD SVR THREAT ON OUR HANDS...BUT THIS IS CONDITIONAL AND
BEST HANDLED BY THE GOING 25-35 PERCENT RAIN CHANCES CURRENTLY IN
THE FORECAST.
WITH CORE OF HIGHEST 925MB/850MB TEMPS COMING ACROSS FORECAST AREA
OVERNIGHT...AND INCREASING SURFACE TO 1KM FLOW...FEEL MOS TEMPS
WAY TOO LOW AND RUNNING ABOVE. WONDERING IF SOME AREAS /CVG/ MAY
STRUGGLE TO DIP BELOW 80 GIVEN THE INCREASING MIXING AND WARM
ADVECTION THROUGH THE NIGHT. THE THREAT FOR AN ELEVATED STORM
WILL PROBABLY CONTINUE ALL NIGHT IN AN ISOLD FASHION VIA STRONG
LOW LEVEL JET AND WARM ADVECTION. AGAIN...LACK OF CONVERGENCE OR
S/W SHOULD KEEP ANY ACTIVITY RELATIVELY ISOLD.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
ATTENTION ON HEAT AND SEVERE WEATHER THREAT ON THURSDAY AFTERNOON
AND EVENING...WITH HEAT THE LESSER OF THE TWO HAZARDS.
REGARDING HEAT...AS MENTIONED ABOVE...CORE OF VERY WARM AIR ALOFT
/850MB TEMPS TO +23C/ WILL BE PUSHING ACROSS AND THEN EAST OF THE
AREA THROUGH THE MORNING YIELDING +20C/21C IN IT/S WAKE FOR THE
AFTERNOON. GIVEN THE MIXED BOUNDARY LAYER RIGHT OFF THE BAT AT
SUNRISE...TEMPS SHOULD RESPOND VERY QUICKLY TO SUNSHINE AND WARM
QUICKLY INTO THE 90S BY LATE MORNING OR NOON. WHILE DEW POINTS WILL
MIX OUT A LITTLE IN THE AFTERNOON AS THE WARM FRONT/MOISTURE
POOLING PUSHES OUT OF THE AREA...DON/T ANTICIPATE TOO MUCH DROP
OFF DURING THE DAY...AND EXPECT DEW POINTS 68-70 MUCH OF AFTERNOON
DESPITE THE BREEZY CONDITIONS. THIS SHOULD PUSH HEAT INDICES TO
AND ABOVE 100 DEGREES FOR THE AFTERNOON AND THUS HEAT ADVISORY ALL
AREAS...WITH EXCESSIVE HEAT WARNING FOR HAMILTON/MONTGOMERY COUNTIES.
BIG FOCUS THOUGH IS THE SEVERE WEATHER THREAT. THURSDAY AFTN HAS
HAD AN ANALOG SIGNAL /CIPS EXPERIMENTAL WARM SEASON GUIDANCE/ OF A
HIGHER END SEVERE THREAT FOR SEVERAL DAYS AND CONFIDENCE CONTINUES
TO HONE IN THAT A REGIONAL SEVERE WEATHER OUTBREAK IS IN THE CARDS
FOR PORTIONS OF THE OHIO VALLEY INCLUDING THE LOCAL FORECAST AREA.
ATTENTION WILL BE ON THE ANOMALOUS /FOR LATE JULY/ SHORTWAVE
TROUGH CURRENTLY NEAR LAKE WINNIPEG...DIGGING SOUTHEAST TOWARD NRN
MN ON THURSDAY. SYNOPTICALLY...DEEP SYSTEMS MOVING THROUGH NRN MN
IN THE WARM SEASON HAVE HIGH CORRELATION TO SIGNIFICANT WEATHER
EVENTS IN THE OHIO VALLEY...AND THIS SETUP APPEARS TO FIT THAT
PATTERN. AS THIS SYSTEM DIGS INTO NRN MN...LOW/MID LEVEL FLOW WILL
BACK EVER SO SLIGHTLY AND MARKEDLY INCREASE...WITH MAINTENANCE OF
A STRONG SWLY LLJ AS WLY MID LEVEL FLOW /35 TO 40KTS/ OVERSPREADS
THAT LLJ AXIS IN THE AFTN. COLD FRONTAL STRUCTURE WILL GET A
LITTLE BETTER ORGANIZED AND SAG INTO THE GREAT LAKES IN THE AFTN
AS CONVERGENCE SLOWLY INCREASES. GIVEN THE AMPLE HEAT/INSTABILITY
BUILDING IN THE WARM SECTOR OVER THE WFO ILN CWA...THE COMBINATION
OF THE INCREASING CONVERGENCE AND MORE IMPORTANTLY THE ARRIVAL OF
A MORE SUBTLE SHORTWAVE /CURRENTLY OVER KS/ SHOULD PROMOTE THE
DEVELOPMENT OF NUMEROUS STORM CLUSTERS WHICH MAY CONGEAL INTO A
LONG /SPATIALLY/ CONVECTIVE SYSTEM WITH /GIVEN CAPE AND SHEAR
PARAMETER SPACE/ AN ABOVE NORMAL CHANCE TO BE A LONGER
LIVED/HIGHER END SEVERE WEATHER MCS.
CIPS ANALOG GUIDANCE USING TOP 8 SVR ANALOGS TO THURSDAY AFTN VIA THE
SPC PPF SYSTEM IS VERY MUCH DIALED IN ON IND/OH/PA AREA AS TARGET
FOR VERY HIGH PROBABILITIES OF SEVERE WEATHER...AND HAS BEEN FOR
SEVERAL DAYS...THIS IS NOT A ONE-RUN-AND-DONE SIGNAL. NEW SPC SWODY2
MIRRORS THIS THREAT AREA...ALBEIT SHIFTED A TAD SOUTH WHICH FITS
HIGHER RESOLUTION /CONVECTION ALLOWING/ 4KM GUIDANCE. LATEST
27.12Z NCEP ARW-CORE HIRES WINDOW RUN IS ESPECIALLY
MENACING...WITH A NRN LINEAR CONVECTIVE SYSTEM HITTING CNTL OHIO
IN THE AFTN TO BE FOLLOWED AN INTENSE BOW ECHO DURING THE EVENING
HITTING THE REST OF THE FORECAST AREA. A WIDESPREAD AND
SIGNIFICANT SEVERE EVENT...WHICH ALSO MIRRORS NCEP NMM /SPC/ WRF.
ADDING FURTHER CONFIDENCE...IS CALIBRATED SPC SREF SEVERE
PROBABILITIES /NOT BASED ON ANALOGS/ THAT ALSO MIRRORS THE ANALOG
AXIS AND CURRENT SPC FORECASTS. SO CONFIDENCE IS THERE...AND
CONTINUED SEVERE MENTIONS IN FORECAST AND RAMPED UP WORDING IN HWO
FOR IMPACTS OF POTENTIAL WIDESPREAD TREE DAMAGE AND SUBSEQUENT
POWER OUTAGES.
IF THE DUAL-MCS SOLUTION VERIFIES...THREAT FOR LOCALIZED FLOODING
VIA THIS 1-2 PUNCH WILL BE INCREASED.
NOT TO PILE IT ON...BUT THE TORNADO THREAT IS NON-ZERO AS
WELL...AND DESPITE MOSTLY SWLY FLOW IN THE BOUNDARY LAYER...THERE
IS DECENT TURNING IN THE LOWEST 1-2KM...SO THERE/S AN OUTSIDE
THREAT OF A TORNADO OR TWO AS LOW LEVEL SHEAR APPEARS STRONG
ENOUGH...AND WILL BE AUGMENTED IF WED NIGHT MCS ACROSS WISC/MICH
CAN SEND A STRONG ENOUGH OUTFLOW BOUNDARY INTO CNTL OHIO BY MORNING/AFTN.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FRIDAY FORECAST IS TRICKY AS DISJOINTED FRONTAL ZONE LAYS ACROSS THE
OHIO VALLEY. PRESSURE TROUGH/BAROCLINIC ZONE/MOISTURE GRADIENT ARE
ALL SOMEWHAT DISPLACED...AND WITH POTENTIAL FOR AN UPPER LEVEL
SHORTWAVE TROUGH TO CROSS THE AREA...THERE WILL REMAIN THE RISK FOR
THUNDERSTORM DEVELOPMENT. MODEL QPF FRIDAY MORNING SEEMS TIED TO
WHATEVER DEVELOPS THURSDAY AFTERNOON...SO NOT SURE IF THESE POPS
WILL PLAY OUT AS ADVERTISED ACROSS THE SOUTH. I EVENTUALLY SPREAD
CHANCE POPS BACK ACROSS THE AREA BY AFTERNOON...HIGHEST IN THE EAST
WHERE SIGNALS ARE BETTER. 12Z NAM SEEMS OVERDONE COMPARED TO OTHER
MODELS IN REINTRODUCING A HOT/HUMID SURGE (AND ENSUING INSTBY) AHEAD
OF THE COLD FRONT...SO WENT CLOSER TO A SREF/ECMWF BLEND.
NEVERTHELESS...RESPECTABLE MID LEVEL FLOW COMBINED WITH THE INSTBY
WILL MEAN THAT ANY STORMS THAT DO DEVELOP COULD BECOME SEVERE...WITH
HIGHEST CHANCES IN THE EAST.
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...ADVANCING COLD FRONT MAY HANG
UP ALONG THE APPALACHIANS...WITH A DISTURBANCE IN THE NORTHWEST FLOW
ALOFT ACTIVATING CONVECTION ALONG IT. THERE ARE AT LEAST SOME
INDICATIONS A SFC WAVE WILL BEND BACK INTO THE UPPER OHIO
VALLEY...SO INCLUDED 20 POPS IN THE EASTERN CWA FOR SATURDAY
AFTERNOON. WITH CAA OVER THE CWA...HIGHS WILL BE AT OR BELOW
SEASONAL NORMALS. 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 /20Z WEDNESDAY THROUGH MONDAY/...
MID LEVEL RIDGE AXIS WILL PUSH EAST ACROSS THE OHIO VALLEY
THROUGH TONIGHT. THIS WILL ALLOW A SURFACE WARM FRONT TO MOVE
NORTHEAST THROUGH THE REGION. ALTHOUGH DECENT INSTABILITY AND SOME
SHEAR WILL ACCOMPANY THIS FRONT LATE THIS AFTERNOON AND
EVENING...FORCING IS NOT THAT SUBSTANTIAL. AS A RESULT...THINK
CHANCES FOR SHOWERS AND STORMS WILL BE AROUND 30 PERCENT. HAVE
DELAYED THE ONSET OF VCTS AT KDAY...KILN...KCVG AND KLUK TO
BETWEEN 21Z AND 22Z. BELIEVE ACTIVITY WILL WANE THIS EVENING WITH
THE LOSS OF DAYTIME HEATING. IT IS UNCLEAR WHETHER ANY CONVECTION
WILL MAKE IT TO CENTRAL OHIO SO HAVE KEPT KCMH AND KLCK DRY. FOR
LATE TONIGHT ONLY SOME SCATTERED CIRRUS OR HIGH LEVEL AC ARE EXPECTED.
THURSDAY IS LOOKING TO BE AN INTERESTING DAY. MID/UPPER LVL FLOW
BACKS TO THE WEST/SOUTHWEST. AT THE SURFACE...A COLD FRONT IS
FORECAST TO SAG SE INTO THE NRN CWFA BY THURSDAY EVENING. AN
EMBEDDED DISTURBANCE IS FORECAST TO MOVE WITHIN THE MID/UPPER LEVEL
FLOW...PASSING ACROSS THE REGION BETWEEN 18Z AND 00Z. A DECENT LOW
LEVEL JET AHEAD OF THE FRONT...DECENT MID LVL JET AROUND 50
KNOTS...AND AMPLE INSTABILITY WILL LIKELY RESULT IN A CONVECTIVE
LINE OF SHOWERS AND THUNDERSTORMS. THE POTENTIAL EXISTS FOR THESE
STORMS TO CONTAIN DAMAGING WINDS...ALTHOUGH LARGE HAIL AND SOME
LOCALLY HEAVY RAIN CAN NOT BE RULED OUT. BEST CHANCE FOR
DEVELOPMENT AND MAINTENANCE FROM WEST TO EAST ACROSS THE REGION
WILL BE BETWEEN 18Z AND 00Z. FRONTAL BOUNDARY IS FORECAST TO STALL
OUT ACROSS THE NRN FORECAST AREA THURSDAY NIGHT AS MID LVL FLOW
TEMPORARILY BECOMES PARALLEL TO THE FRONTAL BOUNDARY. SOME MODELS
ARE INDICTING THAT A WEST/SOUTHWEST ORIENTED LOW LEVEL JET MAY
KEEP CONVECTION GOING IN THE FORM OF CLUSTERS...MAINLY ACRS SRN
PARTS OF THE AREA...THROUGH THURSDAY NIGHT INTO FRIDAY MORNING.
THE PRESSURE GRADIENT AT THE SURFACE IS EXPECTED TO INCREASE
TONIGHT AND THURSDAY AS SURFACE LOW PRESSURE RIPPLES ACROSS THE
NORTHERN GREAT LAKES. THIS WILL RESULT IN BREEZY SOUTHWEST WINDS
WITH GUSTS UP TO 30 KNOTS POSSIBLE THURSDAY OUTSIDE OF
CONVECTION.
OUTLOOK...THUNDERSTORMS POSSIBLE THURSDAY NIGHT INTO FRIDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ034-042-060-
061-070>072-078>081.
HEAT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR OHZ026-034-
035-042>046-051>056-060-062>065-070>074-078>082-088.
EXCESSIVE HEAT WARNING FROM 8 PM THIS EVENING TO 8 PM EDT
THURSDAY FOR OHZ061.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THURSDAY FOR OHZ077.
KY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR KYZ097>100.
HEAT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR KYZ089>100.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR
KYZ089>096.
IN...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR INZ050-058-059.
HEAT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR INZ050-058-
059-066-073>075-080.
EXCESSIVE HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR INZ066-
073>075-080.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...SNYDER
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1041 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 1035 PM...CONVECTION FIRING ACROSS N GA AND SLOWLY DRIFTING
NORTH AND EAST. THE KFFC 00Z RAOB SHOWS A WEAK WARM NOSE THAT IS
OBVIOUSLY BEING EASILY OVERCOME. THE CONVECTION COULD MAKE IT INTO
THE UPPER SAV RIVER VALLEY AND THE SWRN NC MTNS OVERNIGHT GIVEN THIS
MOVEMENT. THE MESOSCALE MODELS AND THE NAM SHOW THIS AS WELL. THE
00Z KGSO RAOB SHOWS A STRONGER WARM NOSE WHICH WILL BE MUCH HARDER
TO OVERCOME. THEREFORE...DO NOT EXPECT THE CONVECTION TO MAKE IT ANY
FARTHER EAST. HAVE CONTINUED THE UPPER SAV RIVER VALLEY POP A LITTLE
LONGER AND ADDED TO THE SWRN MTNS. OTHERWISE...CHANGES FOR CURRENT
CONDITIONS.
AS OF 745 PM...ONLY ECHOES ON RADAR ARE OVER CENTRAL GA AND THE
MIDLANDS. HAVE REMOVED THE EVENING CONVECTION OVER THE MTNS AS THEY
REMAIN CAPPED AS EVIDENCED BY THE PROMINENT WARM NOSE SEEN ON KRNK
SPECIAL 18Z RAOB. THE MESOSCALE GUIDANCE SUGGESTS THAT SOME OF THE
GA/MIDLAND CONVECTION COULD MOVE INTO THE UPPER SAV RIVER VALLEY
THIS EVENING...SO LEFT THE ISOLATED POP THERE. ALL GUIDANCE...EXCEPT
THE RUC AND THE 18Z NAM SHOW A DRY OVERNIGHT PERIOD WITH THE OH
VALLEY CONVECTION REMAINING NORTH OF THE AREA. THE NAM FCST WAS A
BIG CHANGE FROM THE 12Z RUN AND LOOKS FISHY...SO HAVE A DRY
OVERNIGHT FCST. STILL ALLOW THE CONVECTION TO QUICKLY INITIATE OVER
THE MTNS FRI MORN. SKIES ALSO MUCH CLEARER THAN FCST...SO HAVE
BACKED OFF ON CLOUDS THRU THE EVENING...BUT DO BRING IN DEBRIS
CLOUDS AFTER MIDNIGHT. DID NOT MAKE ANY CHANGES TO OVERNIGHT LOWS
BUT KEPT PATCHY FOG OUTSIDE OF THE MTNS AND PATCHY DENSE FOG MTN
VALLEYS.
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 /03Z FRIDAY THROUGH TUESDAY/...
AT KCLT...NO CONVECTION EXPECTED THRU THE OVERNIGHT HOURS. CU WILL
DIMINISH THIS EVENING WITH CIRRUS THEN AC BY MORNING. CU DEVELOPS
FOR THE AFTERNOON WITH AC LEVEL CIG THEN BKN HIGH BASED CU WITH
PROB30 TSRA BY 21Z. LIGHT SW WIND THIS EVENING AND OVERNIGHT WITH AN
INCREASE IN SWLY WINDS BY NOON. COULD SEE SOME GUSTS...BUT WILL NOT
INCLUDE FOR NOW.
ELSEWHERE...SIMILAR CONDITIONS TO KCLT EXCEPT FOR CU LINGERING
LONGER OVER THE MTNS...AND ONSET OF HIGHER CLOUDS EARLIER OVER THE
WEST. MVFR FOG LIKELY AROUND DAYBREAK AT KAVL. CU DEVELOPS BY NOON
ALL AREAS...WITH CONVECTION DEVELOPING FIRST OVER THE MTNS...THEN
HKY...THEN THE SC SITES. HAVE INCLUDED PRO30 FOR ALL AREAS.
DIMINISHING W TO SW WIND THIS EVENING THEN PICKING UP IN SPEED THRU
THE DAY FRI WITH GUSTS POSSIBLE. KAVL THE EXCEPTION WHERE NLY WINDS
EXPECTED FRI.
OUTLOOK...ANOTHER CHANCE FOR THUNDERSTORMS WILL OCCUR SAT AFTERNOON
AS A 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 FROM NOON TO 7 PM EDT FRIDAY FOR GAZ029.
NC...HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR NCZ071-072-082.
SC...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...RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
750 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 745 PM...ONLY ECHOES ON RADAR ARE OVER CENTRAL GA AND THE
MIDLANDS. HAVE REMOVED THE EVENING CONVECTION OVER THE MTNS AS THEY
REMAIN CAPPED AS EVIDENCED BY THE PROMINENT WARM NOSE SEEN ON KRNK
SPECIAL 18Z RAOB. THE MESOSCALE GUIDANCE SUGGESTS THAT SOME OF THE
GA/MIDLAND CONVECTION COULD MOVE INTO THE UPPER SAV RIVER VALLEY
THIS EVENING...SO LEFT THE ISOLATED POP THERE. ALL GUIDANCE...EXCEPT
THE RUC AND THE 18Z NAM SHOW A DRY OVERNIGHT PERIOD WITH THE OH
VALLEY CONVECTION REMAINING NORTH OF THE AREA. THE NAM FCST WAS A
BIG CHANGE FROM THE 12Z RUN AND LOOKS FISHY...SO HAVE A DRY
OVERNIGHT FCST. STILL ALLOW THE CONVECTION TO QUICKLY INITIATE OVER
THE MTNS FRI MORN. SKIES ALSO MUCH CLEARER THAN FCST...SO HAVE
BACKED OFF ON CLOUDS THRU THE EVENING...BUT DO BRING IN DEBRIS
CLOUDS AFTER MIDNIGHT. DID NOT MAKE ANY CHANGES TO OVERNIGHT LOWS
BUT KEPT PATCHY FOG OUTSIDE OF THE MTNS AND PATCHY DENSE FOG MTN
VALLEYS.
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 /00Z FRIDAY THROUGH TUESDAY/...
AT KCLT...NO CONVECTION EXPECTED THRU THE OVERNIGHT HOURS. CU WILL
DIMINISH THIS EVENING WITH CIRRUS THEN AC BY MORNING. CU DEVELOPS
FOR THE AFTERNOON WITH AC LEVEL CIG THEN BKN HIGH BASED CU WITH
PROB30 TSRA BY 21Z. LIGHT SW WIND THIS EVENING AND OVERNIGHT WITH AN
INCREASE IN SWLY WINDS BY NOON. COULD SEE SOME GUSTS...BUT WILL NOT
INCLUDE FOR NOW.
ELSEWHERE...SIMILAR CONDITIONS TO KCLT EXCEPT FOR CU LINGERING
LONGER OVER THE MTNS...AND ONSET OF HIGHER CLOUDS EARLIER OVER THE
WEST. MVFR FOG LIKELY AROUND DAYBREAK AT KAVL. CU DEVELOPS BY NOON
ALL AREAS...WITH CONVECTION DEVELOPING FIRST OVER THE MTNS...THEN
HKY...THEN THE SC SITES. HAVE INCLUDED PRO30 FOR ALL AREAS.
DIMINISHING W TO SW WIND THIS EVENING THEN PICKING UP IN SPEED THRU
THE DAY FRI WITH GUSTS POSSIBLE. KAVL THE EXCEPTION WHERE NLY WINDS
EXPECTED FRI.
OUTLOOK...ANOTHER CHANCE FOR THUNDERSTORMS WILL OCCUR SAT AFTERNOON
AS A 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 FROM NOON TO 7 PM EDT FRIDAY FOR GAZ029.
NC...HEAT ADVISORY FROM NOON TO 7 PM EDT FRIDAY FOR NCZ071-072-082.
SC...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...RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
435 PM EDT WED JUL 25 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 THURSDAY/...
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 /THURSDAY NIGHT 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 /21Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...CONVECTION NEARING THE AIRFIELD SO WILL AMD WITH TEMPO
TSRA. WILL UPDATE WIND FOR CURRENT CONDITIONS...OTHERWISE NO CHANGES
TO LATER PERIODS. NOT LOOKING FOR ANY SIGNIFICANT SIG OR VSBY
RESTRICTIONS OVERNIGHT...THOUGH A PERIOD OF MVFR FOG IS POSSIBLE.
WINDS WILL BE LIGHT OVERNIGHT...INCREASING TO AROUND 10 KTS FROM THE
SOUTHWEST THU AFTN.
AND ELSEWHERE...SCT TSTMS DEVELOPING OVER THE MTNS WILL DRIFT SOUTH
AND DEVELOP OVER THE UPSTATE THRU THE REST OF THE AFTERNOON AND
EARLY EVENING. THIS HAS BEEN ACCOUNTED FOR WITH A VCTS AT MOST
AIRFIELDS. OTHERWISE WINDS WILL BE MAINLY OUT OF THE SW THIS
AFTN...LIGHT TONIGHT...AND INCREASING TO AROUND 10 KTS FROM THE SW
ON THURSDAY. IT WILL BE QUITE HOT TOMORROW...BUT THERE DOESN/T
APPEAR THAT THERE WILL BE MUCH THUNDERSTORM ACTIVITY AS A STRONG
RIDGE BUILDS ACROSS THE REGION.
OUTLOOK...CHANCE FOR CONVECTION WILL INCREASE BY FRIDAY AS A COLD
FRONT MOVES INTO THE AREA. DRIER HIGH PRESSURE BUILDING INTO THE
REGION MAY LIMIT COVERAGE OF CONVECTION BY THE END OF THE WEEKEND.
BEST CHC OF OVERNIGHT RESTRICTIONS THROUGH THE PERIOD WILL BE IN
AREAS THAT SEE LOCALLY HEAVY RAIN.
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 TO 7 PM EDT THURSDAY FOR GAZ029.
NC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR NCZ071-072-
082.
SC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR SCZ009-
011>014-019.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY/RWH
SHORT TERM...NED
LONG TERM...JOH
AVIATION...MCAVOY/RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
247 PM EDT WED JUL 25 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 THURSDAY/...
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 FOOHTILLS 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 /THURSDAY NIGHT 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 /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...THE TDWR SHOWS THAT SOUTHWEST WINDS ARE GRADUALLY WORKING
TOWARD THE SURFACE...AND I HAVE SW WINDS STARTING AT 19 UTC. TSTMS
SHOULD DEVELOP ALONG THE BLUE RIDGE AND DRIFT INTO THE FOOTHILLS
THIS EVENING. IT/S CERTAINLY POSSIBLE THAT CONVECTION WILL MAKE IT
AS FAR EAST AS THE AIRFIELD BY LATE EVENING...BUT I DON/T HAVE MUCH
CONFIDENCE IN THAT SOLUTION. THEREFORE I JUST HAVE SOME VCSH FOR THE
LATE AFTN HOURS. NOT LOOKING FOR ANY SIGNIFICANT SIG OR VSBY
RESTRICTIONS OVERNIGHT...THOUGH A PERIOD OF MVFR FOG IS POSSIBLE.
WINDS WILL BE LIGHT OVERNIGHT...INCREASING TO AROUND 10 KTS FROM THE
SOUTHWEST THU AFTN.
AND ELSEWHERE...SCT TSTMS SHOULD START TO FIRE OVER THE MTNS WITHIN
THE NEXT 1 TO 2 HOURS. THE STORMS MAY DRIFT INTO THE UPSTATE DURING
THE EVENING HOURS. THIS HAS BEEN ACCOUNTED FOR WITH A VCTS AT MOST
AIRFIELDS. OTHERWISE WINDS WILL BE MAINLY OUT OF THE SW THIS
AFTN...LIGHT TONIGHT...AND INCREASING TO AROUND 10 KTS FROM THE SW
ON THURSDAY. IT WILL BE QUITE HOT TOMORROW...BUT THERE DOESN/T
APPEAR THAT THERE WILL BE MUCH THUNDERSTORM ACTIVITY AS A STRONG
RIDGE BUILDS ACROSS THE REGION.
OUTLOOK...CHANCE FOR CONVECTION WILL INCREASE BY FRIDAY AS A COLD
FRONT MOVES INTO THE AREA. DRIER HIGH PRESSURE BUILDING INTO THE
REGION MAY LIMIT COVERAGE OF CONVECTION BY THE END OF THE WEEKEND.
BEST CHC OF OVERNIGHT RESTRICTIONS THROUGH THE PERIOD WILL BE IN
AREAS THAT SEE LOCALLY HEAVY RAIN.
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 TO 7 PM EDT THURSDAY FOR GAZ029.
NC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR NCZ071-072-
082.
SC...HEAT ADVISORY FROM NOON TO 7 PM EDT THURSDAY FOR SCZ009-
011>014-019.
&&
$$
SYNOPSIS...JOH
NEAR TERM...MCAVOY
SHORT TERM...NED
LONG TERM...JOH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
919 PM EDT THU JUL 26 2012
.DISCUSSION...LATE THIS EVENING COLD FRONT IS LOCATED NEAR THE OHIO
RIVER WITH WIDESPREAD CONVECTION ALONG AND JUST SOUTH OF THE
BOUNDARY. DUE TO LOSS OF DAYTIME HEATING...INTENSITY OF THE STORMS
ARE WEAKENING. LATEST RAP AND NAM SHOWS CONVECTION STAYING MAINLY
NORTH OF THE FORECAST AREA OVERNIGHT...BUT MAY MOVE INTO THE FAR
NORTHERN AND WESTERN SECTIONS EARLY FRIDAY MORNING.
MADE SOME MINOR CHANGES TO TEMPERATURES AND POPS FOR TONIGHT...BUT
OVERALL GOING FORECAST LOOKS GOOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 75 92 73 94 70 / 10 50 20 10 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 74 90 71 91 68 / 20 50 20 10 10
OAK RIDGE, TN 74 89 70 91 67 / 20 50 20 10 10
TRI CITIES AIRPORT, TN 70 87 68 88 60 / 20 50 20 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
700 PM CDT THU JUL 26 2012
.UPDATE...
00Z TAF DISCUSSION.
&&
.AVIATION...
QLCS HAS DEVELOPED FROM N AR TO SW IN AND MOVING SOUTHEASTWARD
TOWARDS MID TN...WITH ISOLATED TSRA DEVELOPING IN FRONT OF THE
LINE AS WELL. LATEST LAPS ANALYSIS SHOWS A STRONG INSTABILITY
AXIS FROM SW TO NE ACROSS THE MID STATE WITH CAPES OF 2500-3000
J/KG...AND HRRR GUIDANCE INDICATES LINE WILL SURVIVE AND AFFECT
CKV AROUND 02Z BUT WEAKEN AS IT APPROACHES BNA AND CSV LATER
TONIGHT. WILL SHOW MAIN TSRA IMPACTS AT CKV THIS EVENING WITH
GUSTS TO 30 KTS AND IFR VIS POSSIBLE...AND STRATIFORM TSRA/SHRA
BEHIND THE MAIN LINE THROUGH THE EARLY MORNING HOURS. LESSER
IMPACTS EXPECTED WITH WEAKENING LINE AT BNA AND CSV WITH VCTS OR
TEMPO TSRA. BREAK IN ACTIVITY EXPECTED FRIDAY MORNING BEFORE
REDEVELOPMENT BY AFTERNOON ACROSS MIDDLE TENNESSEE WITH COLD FRONT
MOVING ACROSS.
&&
.PREV DISCUSSION... /ISSUED 623 PM CDT THU JUL 26 2012/
UPDATE...
SEVERE STORMS ASSOC WITH UNSTAB ATM AND H5 TROF DIGGING SOUTH OVR
THE OHVLY. LATEST MODELS DROP ANOTHER S/W TROF IN THE SOUTHERN
PLAINS MOVG SOUTHEAST. THIS SHOULD KEEP STORM ACTIVITY STRONG TO
SEVERE THIS EVENING...AS SYSTEM SPREADS INTO NORTHWEST CORNER OF
MID-TN BTW 8 AND 9 PM.
PREV DISCUSSION... /ISSUED 351 PM CDT THU JUL 26 2012/
DISCUSSION...
CAP ACROSS THE MID STATE IN A HOLDING PATTERN FOR NOW. COULD STILL
SEE SOME ISOL DEVELOPMENT THROUGH THIS EVENING. OTW...A FRONTAL
BOUNDARY IS LOCATED TO OUR NORTH ACROSS CENTRAL IL WITH BETTER
CONVECTION COVERAGE ALONG AND JUST SOUTH OF THIS FEATURE.
FOR TONIGHT...SHOULD SEE A 1-2 PUNCH IN TERMS OF CONVECTION CHANCES.
ISOLATED ACTIVITY IS EXPECTED THROUGH THIS EVENING. THEN...AS THE
AFOREMENTIONED FRONTAL BOUNDARY SINKS SOUTHWARD...A BETTER CHANCE
OF SHOWERS AND TSTMS WILL COMMENCE SOMETIME AROUND MIDNIGHT.
OVERNIGHT CAPE VALUES ARE QUITE IMPRESSIVE AND SINCE GRAPHICAL DEW
POINTS LOOK REASONABLE...STRONG TO PERHAPS SEVERE STORMS WILL BE
POSSIBLE. LATEST 3 HR PRESSURE CHANGE IN SUPPORT OF THE SOUTHWARD
MOVING BOUNDARY.
PRECIP PROBABILITIES WILL NOT BE ALL THAT HIGH TONIGHT AND TUESDAY.
MODELS ARE CONSISTENT WITH A RATHER NARROW RELATIVE DEEP MOISTURE
PROFILE. POPS WILL BE HELD DOWN INTO THE 30-50 PERCENT RANGE TONIGHT
AND FRIDAY.
CAPE VALUES WILL REMAIN ELEVATED THROUGH THE DAY ON FRIDAY. SO
AGAIN...STRONG TO SEVERE STORMS WILL BE POSSIBLE.
DRIER AIR WILL FINALLY WORK INTO THE AREA FRIDAY NIGHT. THIS DRY
PATTERN WILL EXTEND INTO THE FIRST PORTION OF THE EXTENDED FCST.
FOR THE SHORT TERM TEMPS...ABOVE NORMAL TEMPS TO CONTINUE BUT WE
WILL SEE MORE OF A DIURNAL RANGE THIS WEEKEND.
ADDITIONALLY...DEWPOINTS WILL LOWER INTO THE 60S FOR SATURDAY AND
SUNDAY...SO NICE WEEKEND COMING UP.
FOR THE EXT FCST...UPPER HIGH TO HOLD OVER TX AND THIS WILL KEEP
MIDDLE TN UNDER A NW FLOW REGIME. AFTER A DRY PERIOD THIS
WEEKEND...DISTURBANCES AND AN INCREASE IN MOISTURE WILL TRANSLATE
THE PATTERN INTO MORE OF AN ACTIVE NW FLOW. WILL THEREFORE INCLUDE A
CHANCE OF SHOWERS AND TSTMS BEGINNING ON TUESDAY. OTW...TEMPS TO
REMAIN ABOVE NORMAL. STILL A REASONABLE CHANCE THAT THIS JULY WILL
END UP BEING THE 2ND WARMEST ON RECORD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR TNZ005>008-022>029-
056>062-075-093>095.
&&
$$
55
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
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...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...SPEECE
LONG TERM...GIBBS
UPPER AIR/GRAPHICAST...MARTINEZ
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
111 PM CDT WED JUL 25 2012
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...THE MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL
INFLUENCE OF THE CONV COMPLEX THAT HAS BEEN FIRING THIS MORNING
JUST OFFSHORE OF THE MEXICAN COASTLINE BETWEEN BRO AND TAMPICO.
BOTH THE RUC AND NAM PICK UP ON A MID LEVEL VORT POSSIBLY INDUCED
BY THIS CONV AND MOVE IT NORTHWARDS STEADILY THROUGH THURS AND
THURS NIGHT. THIS WILL ALLOW FOR ISOLD TO SCT CONV TO BUILD
MAINTAIN ALONG AND JUST OFFSHORE OF THE LOWER TX COASTLINE
POSSIBLY REDUCING CEILINGS AND VSBYS BRIEFLY DOWN TO MVFR/IFR
LEVELS LATER TONIGHT OR THURSDAY MORNING. AT THIS TIME MY OVERALL
CONFIDENCE LEVEL WITH THIS FEATURE IMPACTING THE AREA AIRPORTS IS
TOO LOW TO INCLUDE ANY MENTION WITH THE 18Z ISSUANCE SINCE MOST
OF THE STRONGER CONV MAY BE LIMITED TO THE BAY AND GULF WATERS.
FOR NOW WILL MAINTAIN VFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 658 AM CDT WED JUL 25 2012/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...VFR IS ANTICIPATED THROUGH THE NEXT 24 HOURS. SURFACE
WINDS WILL INCREASE THROUGH THE DAY TODAY WITH SCATTERED CLOUDINESS.
WINDS WILL BEGIN TO DIMINISH TO LIGHT TO MODERATE LEVELS AROUND
SUNSET THIS EVENING WITH A FEW CLOUDS REMAINING OVERNIGHT TONIGHT.
PREV DISCUSSION... /ISSUED 243 AM CDT WED JUL 25 2012/
SHORT TERM.../TODAY THROUGH THURSDAY/...ISOLATED STREAMER SHOWERS ARE
LOCATED OVER THE LOWER TEXAS COASTAL WATERS RIGHT NOW...A TREND THAT
SHOULD REPEAT ITSELF AGAIN TONIGHT. OTHERWISE...DOMINANT MID-LEVEL
HIGH PRESSURE CENTERED OVER THE SOUTHEAST UNITED STATES WILL PREVAIL
OVER DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY...PRODUCING DRY
WEATHER WITH VERY HOT TEMPERATURES TODAY AND THURSDAY. A COMBINATION
OF RELATIVE HUMIDITY PERCENTAGES AND WINDS AT THE 20-FOOT LEVEL MAY
LEAD TO AN ENHANCED RISK OF WILDFIRE GROWTH AND SPREAD ON THURSDAY...
HOWEVER A RED FLAG WARNING IS NOT EXPECTED TO BE NEEDED AT THAT TIME.
LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY/...
NO BIG CHANGES DONE TO THE LONG TERM FORECAST AT THIS TIME. A
BENIGN WEATHER PATTERN REMAINS THROUGH THE WEEK WITH LITTLE CHANCE
OF ANY CONVECTION. HOT TEMPERATURES WILL BE THE MAIN THREAT THIS
WEEK REMAINING IN THE TRIPLE DIGITS FOR CONSECUTIVE DAYS. RIDGE
OVER THE DESERT SW SHIFTS TO THE CENTRAL PLAINS INTO THE WEEKEND.
S/SE FLOW WILL REMAIN BETWEEN 15 TO 20 KNOTS ACROSS THE RIO GRANDE
VALLEY DUE TO A STRENGTHENING GRADIENT ALONG THE COASTAL COUNTIES.
EXPECT THIS BREEZE CONDITIONS TO CONTINUE INTO SUNDAY AS GRADIENT
REMAINS STRONG. SOUTHEAST WINDS DECREASE INTO NEXT WEEK AS
GRADIENT WEAKENS WITH WINDS BETWEEN 10 HO 15 KNOTS. HOT
TEMPERATURES WILL FEEL BETWEEN THE MID 100S TO THE HIGH 90S.
ABUNDANT MOISTURE OVER CENTRAL MEXICO BORDER WILL REMAIN OVER THE
REGION WITH SOUTHEAST FLOW MOVING MOISTURE TOWARDS THE ARIZONA AND
NEW MEXICO BORDER ENHANCING A MONSOONAL PATTERN IN THIS LOCATIONS.
THIS MOISTURE WILL REMAIN FAR WEST FROM THE CWA WHICH WILL LIMIT
THUNDERSTORM ACTIVITY FOR THE RIO GRANDE VALLEY. HIGH PRESSURE
INTENSIFIES ALONG THE NORTHWESTERN PACIFIC REGION BY MID WEEK. DRY
AIR WILL INFILTRATE ACROSS THE WESTERN PORTION OF THE CWA KEEPING
A DRY PATTERN ACROSS THE AREA. LOW TEMPERATURE WILL BE BETWEEN IN
THE 80S.
MARINE...TODAY THROUGH THURSDAY...BUOY 42020 REPORTED SOUTH WINDS
AROUND 18 KNOTS GUSTING TO AROUND 21 KNOTS WITH SEAS SLIGHTLY UNDER
3.5 FEET WITH A PERIOD OF 4 SECONDS AT 02 CDT/07 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST TODAY THROUGH
TONIGHT AS HIGH PRESSURE OVER THE GULF OF MEXICO INTERACTS WITH LOW
PRESSURE OVER NORTHERN MEXICO. SMALL CRAFT WILL LIKELY NEED TO
EXERCISE CAUTION DURING THIS TIME ALONG THE LOWER TEXAS COAST. ON
THURSDAY...A COMBINATION OF SMALL CRAFT EXERCISE CAUTION AND SMALL
CRAFT ADVISORY IS LIKELY DUE TO CONTINUED MODERATE SEAS AND SLIGHTLY
STRONGER WINDS.
THURSDAY NIGHT THROUGH WEDNESDAY...
BENIGN WEATHER EXPECTED WITH S/SE WINDS THROUGH THE LONG TERM PERIOD.
EXPECT SEAS TO REMAIN BETWEEN 2 TO 4 FEET FRIDAY WITH SE WINDS.
THIS WINDS WILL BEGIN TO LOWER FOR THE WEEKEND AND REMAIN BETWEEN 2
TO 3 FEET THE REMAINDER OF THE LONG TERM PERIOD. NO SCA OR SCEC
EXPECTED AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 81 96 82 90 / 0 0 0 0
BROWNSVILLE 79 96 80 93 / 0 0 0 0
HARLINGEN 78 100 79 96 / 0 0 0 0
MCALLEN 79 102 80 98 / 0 0 0 0
RIO GRANDE CITY 79 102 79 99 / 0 0 0 0
SOUTH PADRE ISLAND 82 91 83 86 / 0 0 10 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...60
LONG TERM...68
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1238 PM CDT WED JUL 25 2012
.AVIATION...
STILL EXPECT ISOLATED TO SCATTERED THUNDERSTORMS DEVELOP LATE THIS
AFTN IN A MOISTURE AXIS LOCATED NEAR THE CAPROCK ESCARPMENT AS
WELL AS ON THE HIGH TERRAIN ALONG THE NEW MEXICO STATE LINE.
FAVORED MOVEMENT OF STORMS TOWARD AN EASTERLY COMPONENT COULD
BRING TSRA TO BOTH TAF SITES. HOWEVER...AREAL EXTENT WITHIN 9 HOUR
WINDOW NOT HIGH ENOUGH TO WARRANT TEMPO GROUPS ATTM. THUS WILL
PULL THUNDER MENTION FROM BOTH TAFS AND REEVALUATE LATER THIS AFTN.
&&
.PREV DISCUSSION... /ISSUED 633 AM CDT WED JUL 25 2012/
AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE DAY. BY EARLY
AFTERNOON...ISOLATED TO SCATTERED THUNDERSTORMS MAY DEVELOP NEAR
THE KLBB TERMINAL AND EVENTUALLY SPREAD TOWARDS THE KCDS TERMINAL.
PRECIPITATION SHOULD END BEFORE MIDNIGHT LEAVING VFR CONDITIONS IN
PLACE.
JORDAN
PREV DISCUSSION... /ISSUED 403 AM CDT WED JUL 25 2012/
SHORT TERM...
00Z UPPER-AIR ANALYSIS AND WV SATELLITE SHOWS CONSIDERABLE MOISTURE
IN PLACE ACROSS THE REGION. KAMA AND KMAF RESPECTIVELY HAVE 1.14
AND 1.11 INCH PRECIPITABLE WATER VALUES WHICH IS SOMEWHAT HIGH FOR
THIS TIME OF YEAR. ALSO ARE SEEING SOME SHOWERS EARLY THIS MORNING
ON THE RADAR ASSOCIATED WITH AN AREA OF MID-LEVEL CLOUD COVER.
UPPER-AIR ANALYSIS SHOWS A TROF AXIS LOCATED ACROSS EASTERN NEW
MEXICO THIS MORNING WITH THE MODELS SLOWLY SHIFTING THIS TOWARDS
THE STATE LINE THROUGH THE DAY. MONSOON MOISTURE PLUME SHOULD MOVE
BACK OVER THE WESTERN HALF OF THE FORECAST AREA THIS AFTERNOON AND
DAYTIME HEATING SHOULD HELP TO DESTABILIZE THE ATMOSPHERE RESULTING
IN A BIT MORE WIDESPREAD STORM ACTIVITY COMPARED TO YESTERDAY. ALL
OF THIS IS ACCORDING TO THE VARIOUS RESOLUTIONS OF THE NAM MODEL AND
TO LESSER EXTENT THE TTU WRF. THE GFS AND LATEST HRRR ARE NOT AS
OPTIMISTIC AT ALL. WILL KEEP CHANCE OF THUNDERSTORMS OVER THE
CENTRAL SOUTH PLAINS WHERE THE INSTABILITY AXIS MAY TRY TO SET UP
THIS AFTERNOON AND THEN SHIFT THIS AREA WEST FOR EARLY TONIGHT.
THERE COULD BE A FEW SHOWERS THAT LINGER ACROSS THE AREA INTO
THURSDAY MORNING AS MONSOON MOISTURE AND TROF AXIS REMAIN NEAR THE
REGION. HIGH TEMPERATURES CAME IN A BIT WARMER ON THE MOS GUIDANCE
AND WILL KEEP THINGS A FEW DEGREES UNDER THIS DUE TO THE EXPECTED
CLOUD COVER AND SHOWERS.
JORDAN
LONG TERM...
THE EXTENDED FORECAST WILL BE PUNCTUATED BY MORE SUMMER
HEAT...THOUGH THUNDERSTORMS MAY ALSO GIVE SOME LOCATIONS BRIEF
RELIEF THURSDAY AND/OR FRIDAY.
A SHORTWAVE TROUGH WILL GLIDE ACROSS THE MIDWEST ON THURSDAY...JUST
GRAZING THE SOUTHERN PLAINS WITH WEAK 500-300 MB LAYER Q-VECTOR
CONVERGENCE AND DRAWING THE MONSOONAL MOISTURE PLUME ACROSS WEST
TEXAS. AT THE SAME TIME...THE TAIL END OF A COLD FRONT WILL EDGE
TOWARD OR INTO THE AREA. THE 00Z GFS AND NAM DO HAVE THE THE WIND
SHIFT ROUGHLY BISECTING THE FA FROM SW TO NE MIDDAY THURSDAY BEFORE
STALLING OUT...WHILE THE ECMWF IS SOMEWHAT FURTHER NORTH...INTO THE
TEXAS PANHANDLE. GIVEN THAT THE POSITION OF THE FRONTAL ZONE IS
SOMEWHAT IN QUESTION...DETAILS IN CONVECTIVE INITIATION ALSO REMAIN
SOMEWHAT UNCERTAIN...BUT WITH WEAK UPPER SUPPORT AND A RELATIVELY
MOIST ATMOSPHERE IN PLACE /PWATS AT 130 TO OVER 150 PERCENT OF
AVERAGE/...EXPECT DAYTIME HEATING TO LEAD TO SCATTERED AFTERNOON AND
EVENING CONVECTION. PROGGED SFC MOISTURE AND RESULTANT INSTABILITY
WILL BE A LITTLE HIGHER THAN WE HAVE SEEN RECENTLY THOUGH DEEP-LAYER
SHEAR WILL STILL BE RATHER MEAGER. HENCE...DO NOT ANTICIPATE MUCH
STORM ORGANIZATION...BUT COULD SEE A FEW STRONGER CORES THAT COULD
PRODUCE SMALL HAIL...STOUT DOWNBURST WINDS AND LOCALLY HEAVY RAINS.
ANY WEAK UPPER SUPPORT THURSDAY WILL QUICKLY WANE FRIDAY AS AN UPPER
LEVEL RIDGE STRENGTHENS AND EXTENDS EASTWARD FROM THE SOUTHERN
ROCKIES INTO THE SOUTHERN PLAINS. STILL...RESIDUAL LOW-LEVEL
MOISTURE...A THINNING MID-LEVEL MOISTURE PLUME...STRONG HEATING AND
PERHAPS A SFC BOUNDARY IN THE AREA MAY BE ENOUGH TO GENERATE
ISOLATED TO WIDELY SCATTERED CONVECTION FRIDAY AFTERNOON AND
EVENING. BEYOND THAT...THOUGH...THE UPPER RIDGE WILL BECOME CENTERED
ACROSS THE SOUTHERN PLAINS AND IT SHOULD PUT THE KIBOSH ON STORM
CHANCES THIS WEEKEND AND INTO AT LEAST THE FIRST PART OF NEXT WEEK
AS IT PROMOTES SUBSIDENCE AND SHIFTS THE MONSOON MOISTURE BACK TO
THE WEST. THE UPPER RIDGE AXIS MAY ATTEMPT TO SHIFT BACK WEST OF THE
AREA BY DAY 7 OR DAY 8 IF THE GFS IS CORRECT...BUT THE ECMWF KEEPS
THE CENTER OF THE HIGH NEARBY THROUGH THE REMAINDER OF NEXT WEAK.
THUS...EXPECT HOT TEMPERATURES TO CONTINUE...AND HAVE FAVORED HIGHS
SLIGHTLY ABOVE GUIDANCE FROM THIS WEEKEND ONWARD...GIVEN RECENT
GUIDANCE BIASES WITH THE PREVIOUS UPPER RIDGE ACROSS THE SOUTH
PLAINS THIS PAST WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 95 67 94 66 92 / 20 30 30 30 20
TULIA 94 68 96 67 92 / 20 30 30 30 20
PLAINVIEW 94 69 94 69 92 / 30 20 30 30 20
LEVELLAND 95 69 95 69 93 / 30 20 30 30 20
LUBBOCK 96 71 96 71 95 / 30 20 30 30 20
DENVER CITY 96 70 96 69 94 / 20 20 30 30 20
BROWNFIELD 95 71 96 69 94 / 30 20 30 30 20
CHILDRESS 100 75 100 74 99 / 20 20 30 30 20
SPUR 97 72 98 72 100 / 30 20 30 30 20
ASPERMONT 99 76 102 76 101 / 30 20 30 30 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
648 AM CDT WED JUL 25 2012
.AVIATION...
FOR THE 12Z TAFS...VFR CONDITIONS AND SOUTHERLY FLOW ARE EXPECTED
TO PERSIST THROUGH THE VALID FORECAST PERIOD.
THE EARLY MORNING STRATUS WAS CREEPING UP THE INTERSTATE 35
CORRIDOR SOUTH OF WACO HAS DISSIPATED AS OF 1130Z. SOME MVFR CIGS
REMAIN IN PLACE SOUTHEAST OF WACO...BUT THIS BAND OF STRATUS WAS
BUILDING NORTHEAST AWAY FROM THE AIRPORT PER INFRARED SATELLITE
IMAGERY. AS A RESULT PULLED MENTION OF MVFR CIGS OUT OF THE WACO
TAF THIS MORNING AND REMOVED MENTION OF SCATTERED LOW CLOUDS
ACROSS THE METROPLEX BASED ON EARLY MORNING SATELLITE TRENDS.
EXPECT SOUTHERLY FLOW TO STRENGTHEN A BIT AFTER A FEW HOURS OF
HEATING. RAP FORECAST SOUNDINGS INDICATE THAT THE ENVIRONMENT WILL
BE UNCAPPED OVER NORTH AND CENTRAL TX THIS AFTERNOON...WHICH
ALLOWS THIS MODEL TO INITIATE SOME ISOLATED THUNDERSTORM ACTIVITY
DURING THE PEAK HEATING HOURS OF THE DAY. AT THIS TIME THINK THAT
THE RAP IS OVERESTIMATING THE QUALITY AND DEPTH OF LOW LEVEL
MOISTURE FIELDS AS ALMOST ALL OTHER GUIDANCE INDICATES LOW LEVEL
MOISTURE MIXING OUT DURING PEAK HEATING. THINK THAT WE HAVE ENOUGH
MOISTURE IN PLACE TO SEE A CUMULUS FIELD DEVELOP THIS
AFTERNOON...BUT THINK THAT LOW LEVEL MOISTURE MIXING OUT WILL KEEP
US CAPPED NEAR AREA AIRPORTS FOR THE NEXT 24 HRS.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 313 AM CDT WED JUL 25 2012/
AT 00Z...HIGH PRESSURE WAS ANALYZED ON UPPER AIR CHARTS ACROSS THE
SOUTHEASTERN CONUS...WITH ANOTHER HIGH CENTER ACROSS THE DESERT
SOUTHWEST. A STRONG TROUGH IS CURRENTLY IN SOUTHERN CANADA...AND A
WEAKER TROUGH AXIS IS CURRENTLY OVER WEST TX AND THE PANHANDLE.
WITH THIS SETUP...MOSTLY DRY WEATHER IS EXPECTED TODAY FOR NORTH
TEXAS...WITH RAIN CHANCES TO OUR WEST. 850 TEMPS WILL BE WARMER
THIS AFTERNOON AND HIGHS TODAY WILL TOP OUT A DEGREE OR TWO HIGHER
THAN YESTERDAY. WINDS TODAY ARE EXPECTED TO BE BREEZY DUE TO A
STRENGTHENING SURFACE LOW IN THE CENTRAL PLAINS. WITH MINIMUM
HUMIDITY VALUES NEAR OR BELOW 30 PERCENT WEST OF INTERSTATE
35...ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED.
AS WE MOVE INTO TOMORROW...THE UPPER TROUGH IN CANADA WILL MOVE
THROUGH THE NORTHERN PLAINS. THE RIDGE ACROSS THE SOUTHEAST WILL
THEN BE FORCED TO WEAKEN AND REESTABLISH FURTHER TO THE EAST AND THE
SOUTHWEST RIDGE WILL STRENGTHEN/AMPLIFY ON THE BACKSIDE OF THE
EASTWARD MOVING TROUGH. THIS PATTERN PLACES OKLAHOMA UNDERNEATH A
DEFORMATION AXIS FOR THURSDAY AFTERNOON. WITH LITTLE INHIBITION
AND AMPLE INSTABILITY...SCATTERED THUNDERSTORMS ARE EXPECTED
NORTH OF THE RED RIVER. MOST ACTIVITY SHOULD REMAIN IN
OKLAHOMA...BUT ANY SOUTHWARD MOVING BOUNDARIES COULD IGNITE A FEW
STORMS IN OUR NORTHERN COUNTIES AND WILL CONTINUE THE 20 POPS FOR
THURSDAY.
BY FRIDAY...THE RIDGE ACROSS THE WESTERN CONUS WILL STRENGTHEN AND
SHIFT SOUTHEAST CONTINUING BEHIND THE TROUGH MOVING ACROSS THE
MIDWEST. THIS EQUATES TO THE DEFORMATION AXIS SETTING UP FURTHER
TO THE SOUTH...AND SHOULD BE IN OUR NORTHERN CWA. NO CAP IS
EXPECTED AND ISOLATED TO SCATTERED CONVECTION SHOULD OCCUR MAINLY
IN THE AFTERNOON TO EARLY EVENING HOURS. SHEAR IS EXPECTED TO BE
MINIMAL AND INDIVIDUAL UPDRAFTS SHOULD QUICKLY WEAKEN. WITH CLOUD
BASES AROUND 7KFT...CANT RULE OUT 40-60 MPH DOWNBURST WINDS WITH
COLLAPSING THUNDERSTORMS. HIGHS FRIDAY SHOULD STAY BELOW THE
CENTURY MARK WITH THE EXTRA CLOUD COVER AND STORMS AROUND.
FOR SATURDAY...THE UPPER RIDGE WILL CONTINUE TO MOVE SOUTHEAST AND
CENTER ITSELF ACROSS THE AREA...THUS ENDING THE RAIN CHANCES AND
INCREASING TEMPERATURES. THE RIDGE IS NOT EXPECTED TO MOVE MUCH
THROUGH THE END OF THE PERIOD AND A STREAK OF 100 DEGREE DAYS IS
EXPECTED BEGINNING SATURDAY. A HEAT ADVISORY MAY BE NEEDED FOR THE
METROPLEX THIS WEEKEND...AS AFTERNOON HEAT INDICES ARE ABOVE 105
DEGREES AND MORNINGS LOWS REMAIN ABOVE 78 DEGREES.
85/NH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 99 79 100 79 99 / 0 5 10 10 20
WACO, TX 99 78 97 77 98 / 0 5 10 10 10
PARIS, TX 98 74 98 76 96 / 0 5 10 10 30
DENTON, TX 100 77 100 75 99 / 0 5 20 20 30
MCKINNEY, TX 98 76 100 74 98 / 0 5 10 10 20
DALLAS, TX 99 80 100 79 99 / 0 5 10 10 20
TERRELL, TX 98 76 98 75 99 / 0 5 10 10 20
CORSICANA, TX 99 77 97 76 99 / 0 5 10 10 10
TEMPLE, TX 97 74 97 73 98 / 0 5 10 10 10
MINERAL WELLS, TX 101 75 100 75 99 / 0 5 10 10 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
633 AM CDT WED JUL 25 2012
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE DAY. BY EARLY
AFTERNOON...ISOLATED TO SCATTERED THUNDERSTORMS MAY DEVELOP NEAR
THE KLBB TERMINAL AND EVENTUALLY SPREAD TOWARDS THE KCDS TERMINAL.
PRECIPITATION SHOULD END BEFORE MIDNIGHT LEAVING VFR CONDITIONS IN
PLACE.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 403 AM CDT WED JUL 25 2012/
SHORT TERM...
00Z UPPER-AIR ANALYSIS AND WV SATELLITE SHOWS CONSIDERABLE MOISTURE
IN PLACE ACROSS THE REGION. KAMA AND KMAF RESPECTIVELY HAVE 1.14
AND 1.11 INCH PRECIPITABLE WATER VALUES WHICH IS SOMEWHAT HIGH FOR
THIS TIME OF YEAR. ALSO ARE SEEING SOME SHOWERS EARLY THIS MORNING
ON THE RADAR ASSOCIATED WITH AN AREA OF MID-LEVEL CLOUD COVER.
UPPER-AIR ANALYSIS SHOWS A TROF AXIS LOCATED ACROSS EASTERN NEW
MEXICO THIS MORNING WITH THE MODELS SLOWLY SHIFTING THIS TOWARDS
THE STATE LINE THROUGH THE DAY. MONSOON MOISTURE PLUME SHOULD MOVE
BACK OVER THE WESTERN HALF OF THE FORECAST AREA THIS AFTERNOON AND
DAYTIME HEATING SHOULD HELP TO DESTABILIZE THE ATMOSPHERE RESULTING
IN A BIT MORE WIDESPREAD STORM ACTIVITY COMPARED TO YESTERDAY. ALL
OF THIS IS ACCORDING TO THE VARIOUS RESOLUTIONS OF THE NAM MODEL AND
TO LESSER EXTENT THE TTU WRF. THE GFS AND LATEST HRRR ARE NOT AS
OPTIMISTIC AT ALL. WILL KEEP CHANCE OF THUNDERSTORMS OVER THE
CENTRAL SOUTH PLAINS WHERE THE INSTABILITY AXIS MAY TRY TO SET UP
THIS AFTERNOON AND THEN SHIFT THIS AREA WEST FOR EARLY TONIGHT.
THERE COULD BE A FEW SHOWERS THAT LINGER ACROSS THE AREA INTO
THURSDAY MORNING AS MONSOON MOISTURE AND TROF AXIS REMAIN NEAR THE
REGION. HIGH TEMPERATURES CAME IN A BIT WARMER ON THE MOS GUIDANCE
AND WILL KEEP THINGS A FEW DEGREES UNDER THIS DUE TO THE EXPECTED
CLOUD COVER AND SHOWERS.
JORDAN
LONG TERM...
THE EXTENDED FORECAST WILL BE PUNCTUATED BY MORE SUMMER
HEAT...THOUGH THUNDERSTORMS MAY ALSO GIVE SOME LOCATIONS BRIEF
RELIEF THURSDAY AND/OR FRIDAY.
A SHORTWAVE TROUGH WILL GLIDE ACROSS THE MIDWEST ON THURSDAY...JUST
GRAZING THE SOUTHERN PLAINS WITH WEAK 500-300 MB LAYER Q-VECTOR
CONVERGENCE AND DRAWING THE MONSOONAL MOISTURE PLUME ACROSS WEST
TEXAS. AT THE SAME TIME...THE TAIL END OF A COLD FRONT WILL EDGE
TOWARD OR INTO THE AREA. THE 00Z GFS AND NAM DO HAVE THE THE WIND
SHIFT ROUGHLY BISECTING THE FA FROM SW TO NE MIDDAY THURSDAY BEFORE
STALLING OUT...WHILE THE ECMWF IS SOMEWHAT FURTHER NORTH...INTO THE
TEXAS PANHANDLE. GIVEN THAT THE POSITION OF THE FRONTAL ZONE IS
SOMEWHAT IN QUESTION...DETAILS IN CONVECTIVE INITIATION ALSO REMAIN
SOMEWHAT UNCERTAIN...BUT WITH WEAK UPPER SUPPORT AND A RELATIVELY
MOIST ATMOSPHERE IN PLACE /PWATS AT 130 TO OVER 150 PERCENT OF
AVERAGE/...EXPECT DAYTIME HEATING TO LEAD TO SCATTERED AFTERNOON AND
EVENING CONVECTION. PROGGED SFC MOISTURE AND RESULTANT INSTABILITY
WILL BE A LITTLE HIGHER THAN WE HAVE SEEN RECENTLY THOUGH DEEP-LAYER
SHEAR WILL STILL BE RATHER MEAGER. HENCE...DO NOT ANTICIPATE MUCH
STORM ORGANIZATION...BUT COULD SEE A FEW STRONGER CORES THAT COULD
PRODUCE SMALL HAIL...STOUT DOWNBURST WINDS AND LOCALLY HEAVY RAINS.
ANY WEAK UPPER SUPPORT THURSDAY WILL QUICKLY WANE FRIDAY AS AN UPPER
LEVEL RIDGE STRENGTHENS AND EXTENDS EASTWARD FROM THE SOUTHERN
ROCKIES INTO THE SOUTHERN PLAINS. STILL...RESIDUAL LOW-LEVEL
MOISTURE...A THINNING MID-LEVEL MOISTURE PLUME...STRONG HEATING AND
PERHAPS A SFC BOUNDARY IN THE AREA MAY BE ENOUGH TO GENERATE
ISOLATED TO WIDELY SCATTERED CONVECTION FRIDAY AFTERNOON AND
EVENING. BEYOND THAT...THOUGH...THE UPPER RIDGE WILL BECOME CENTERED
ACROSS THE SOUTHERN PLAINS AND IT SHOULD PUT THE KIBOSH ON STORM
CHANCES THIS WEEKEND AND INTO AT LEAST THE FIRST PART OF NEXT WEEK
AS IT PROMOTES SUBSIDENCE AND SHIFTS THE MONSOON MOISTURE BACK TO
THE WEST. THE UPPER RIDGE AXIS MAY ATTEMPT TO SHIFT BACK WEST OF THE
AREA BY DAY 7 OR DAY 8 IF THE GFS IS CORRECT...BUT THE ECMWF KEEPS
THE CENTER OF THE HIGH NEARBY THROUGH THE REMAINDER OF NEXT WEAK.
THUS...EXPECT HOT TEMPERATURES TO CONTINUE...AND HAVE FAVORED HIGHS
SLIGHTLY ABOVE GUIDANCE FROM THIS WEEKEND ONWARD...GIVEN RECENT
GUIDANCE BIASES WITH THE PREVIOUS UPPER RIDGE ACROSS THE SOUTH
PLAINS THIS PAST WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 95 67 94 66 92 / 20 30 30 30 20
TULIA 94 68 96 67 92 / 20 30 30 30 20
PLAINVIEW 94 69 94 69 92 / 30 20 30 30 20
LEVELLAND 95 69 95 69 93 / 30 20 30 30 20
LUBBOCK 96 71 96 71 95 / 30 20 30 30 20
DENVER CITY 96 70 96 69 94 / 20 20 30 30 20
BROWNFIELD 95 71 96 69 94 / 30 20 30 30 20
CHILDRESS 100 75 100 74 99 / 20 20 30 30 20
SPUR 97 72 98 72 100 / 30 20 30 30 20
ASPERMONT 99 76 102 76 101 / 30 20 30 30 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
403 AM CDT WED JUL 25 2012
.SHORT TERM...
00Z UPPER-AIR ANALYSIS AND WV SATELLITE SHOWS CONSIDERABLE MOISTURE
IN PLACE ACROSS THE REGION. KAMA AND KMAF RESPECTIVELY HAVE 1.14
AND 1.11 INCH PRECIPITABLE WATER VALUES WHICH IS SOMEWHAT HIGH FOR
THIS TIME OF YEAR. ALSO ARE SEEING SOME SHOWERS EARLY THIS MORNING
ON THE RADAR ASSOCIATED WITH AN AREA OF MID-LEVEL CLOUD COVER.
UPPER-AIR ANALYSIS SHOWS A TROF AXIS LOCATED ACROSS EASTERN NEW
MEXICO THIS MORNING WITH THE MODELS SLOWLY SHIFTING THIS TOWARDS
THE STATE LINE THROUGH THE DAY. MONSOON MOISTURE PLUME SHOULD MOVE
BACK OVER THE WESTERN HALF OF THE FORECAST AREA THIS AFTERNOON AND
DAYTIME HEATING SHOULD HELP TO DESTABILIZE THE ATMOSPHERE RESULTING
IN A BIT MORE WIDESPREAD STORM ACTIVITY COMPARED TO YESTERDAY. ALL
OF THIS IS ACCORDING TO THE VARIOUS RESOLUTIONS OF THE NAM MODEL AND
TO LESSER EXTENT THE TTU WRF. THE GFS AND LATEST HRRR ARE NOT AS
OPTIMISTIC AT ALL. WILL KEEP CHANCE OF THUNDERSTORMS OVER THE
CENTRAL SOUTH PLAINS WHERE THE INSTABILITY AXIS MAY TRY TO SET UP
THIS AFTERNOON AND THEN SHIFT THIS AREA WEST FOR EARLY TONIGHT.
THERE COULD BE A FEW SHOWERS THAT LINGER ACROSS THE AREA INTO
THURSDAY MORNING AS MONSOON MOISTURE AND TROF AXIS REMAIN NEAR THE
REGION. HIGH TEMPERATURES CAME IN A BIT WARMER ON THE MOS GUIDANCE
AND WILL KEEP THINGS A FEW DEGREES UNDER THIS DUE TO THE EXPECTED
CLOUD COVER AND SHOWERS.
JORDAN
&&
.LONG TERM...
THE EXTENDED FORECAST WILL BE PUNCTUATED BY MORE SUMMER
HEAT...THOUGH THUNDERSTORMS MAY ALSO GIVE SOME LOCATIONS BRIEF
RELIEF THURSDAY AND/OR FRIDAY.
A SHORTWAVE TROUGH WILL GLIDE ACROSS THE MIDWEST ON THURSDAY...JUST
GRAZING THE SOUTHERN PLAINS WITH WEAK 500-300 MB LAYER Q-VECTOR
CONVERGENCE AND DRAWING THE MONSOONAL MOISTURE PLUME ACROSS WEST
TEXAS. AT THE SAME TIME...THE TAIL END OF A COLD FRONT WILL EDGE
TOWARD OR INTO THE AREA. THE 00Z GFS AND NAM DO HAVE THE THE WIND
SHIFT ROUGHLY BISECTING THE FA FROM SW TO NE MIDDAY THURSDAY BEFORE
STALLING OUT...WHILE THE ECMWF IS SOMEWHAT FURTHER NORTH...INTO THE
TEXAS PANHANDLE. GIVEN THAT THE POSITION OF THE FRONTAL ZONE IS
SOMEWHAT IN QUESTION...DETAILS IN CONVECTIVE INITIATION ALSO REMAIN
SOMEWHAT UNCERTAIN...BUT WITH WEAK UPPER SUPPORT AND A RELATIVELY
MOIST ATMOSPHERE IN PLACE /PWATS AT 130 TO OVER 150 PERCENT OF
AVERAGE/...EXPECT DAYTIME HEATING TO LEAD TO SCATTERED AFTERNOON AND
EVENING CONVECTION. PROGGED SFC MOISTURE AND RESULTANT INSTABILITY
WILL BE A LITTLE HIGHER THAN WE HAVE SEEN RECENTLY THOUGH DEEP-LAYER
SHEAR WILL STILL BE RATHER MEAGER. HENCE...DO NOT ANTICIPATE MUCH
STORM ORGANIZATION...BUT COULD SEE A FEW STRONGER CORES THAT COULD
PRODUCE SMALL HAIL...STOUT DOWNBURST WINDS AND LOCALLY HEAVY RAINS.
ANY WEAK UPPER SUPPORT THURSDAY WILL QUICKLY WANE FRIDAY AS AN UPPER
LEVEL RIDGE STRENGTHENS AND EXTENDS EASTWARD FROM THE SOUTHERN
ROCKIES INTO THE SOUTHERN PLAINS. STILL...RESIDUAL LOW-LEVEL
MOISTURE...A THINNING MID-LEVEL MOISTURE PLUME...STRONG HEATING AND
PERHAPS A SFC BOUNDARY IN THE AREA MAY BE ENOUGH TO GENERATE
ISOLATED TO WIDELY SCATTERED CONVECTION FRIDAY AFTERNOON AND
EVENING. BEYOND THAT...THOUGH...THE UPPER RIDGE WILL BECOME CENTERED
ACROSS THE SOUTHERN PLAINS AND IT SHOULD PUT THE KIBOSH ON STORM
CHANCES THIS WEEKEND AND INTO AT LEAST THE FIRST PART OF NEXT WEEK
AS IT PROMOTES SUBSIDENCE AND SHIFTS THE MONSOON MOISTURE BACK TO
THE WEST. THE UPPER RIDGE AXIS MAY ATTEMPT TO SHIFT BACK WEST OF THE
AREA BY DAY 7 OR DAY 8 IF THE GFS IS CORRECT...BUT THE ECMWF KEEPS
THE CENTER OF THE HIGH NEARBY THROUGH THE REMAINDER OF NEXT WEAK.
THUS...EXPECT HOT TEMPERATURES TO CONTINUE...AND HAVE FAVORED HIGHS
SLIGHTLY ABOVE GUIDANCE FROM THIS WEEKEND ONWARD...GIVEN RECENT
GUIDANCE BIASES WITH THE PREVIOUS UPPER RIDGE ACROSS THE SOUTH
PLAINS THIS PAST WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 95 67 94 66 92 / 20 30 30 30 20
TULIA 94 68 96 67 92 / 20 30 30 30 20
PLAINVIEW 94 69 94 69 92 / 30 20 30 30 20
LEVELLAND 95 69 95 69 93 / 30 20 30 30 20
LUBBOCK 96 71 96 71 95 / 30 20 30 30 20
DENVER CITY 96 70 96 69 94 / 20 20 30 30 20
BROWNFIELD 95 71 96 69 94 / 30 20 30 30 20
CHILDRESS 100 75 100 74 99 / 20 20 30 30 20
SPUR 97 72 98 72 100 / 30 20 30 30 20
ASPERMONT 99 76 102 76 101 / 30 20 30 30 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/23
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1129 PM CDT TUE JUL 24 2012
.AVIATION...
ISOLATED THUNDERSTORMS NOT EXPECTED TO HAVE A DIRECT IMPACT ON
TERMINALS OVERNIGHT. SOUTHERLY SURFACE WINDS WILL VEER GRADUALLY
OVERNIGHT...BECOMING SOUTH OR SOUTH SOUTHWEST BY 14Z WEDNESDAY.
SURFACE WINDS EXPECTED TO GUST ABOVE 20 KT DURING THE DAY ON
WEDNESDAY...PRIOR TO ARRIVAL OF COLD FRONT. COLD FRONT IS FORECAST
TO ARRIVE AT NORTHERN TERMINALS BETWEEN 01Z AND 03Z THURSDAY...WITH
SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP ALONG AND AHEAD OF FRONT
DURING THE AFTERNOON AND EVENING. WILL WAIT FOR SIGNAL OF TIMING AND
LOCATION OF THUNDERSTORMS TO BECOME MORE PRONOUNCED BEFORE ADDING
SAME TO FORECAST. VFR FORECAST CONTINUES NEXT 24 HOURS.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 955 PM CDT TUE JUL 24 2012/
UPDATE...
ALTHOUGH THE 00Z RUNS OF THE NAM AND RUC FORECASTING DRIER CONDITIONS
LATER TONIGHT...THE RUC INDICATING CONVECTION SPREADING FROM WEST TO
EAST THROUGH AROUND 06Z TO 09Z WEDNESDAY. WITH MID AND UPPER TROUGH
LOCATED OVER THE CENTRAL AND SOUTHERN ROCKIES INTO THE PANHANDLES AND
PRECIP WATERS BETWEEN ONE AND ONE AND ONE QUARTER INCHES ALONG WITH
PLENTY OF LOW LEVEL MOISTURE AND SHORTWAVE ENERGY ACROSS THE FORECAST
AREA...SPREAD SLIGHT CHANCE POPS EASTWARD ACROSS ALL OF THE
PANHANDLES THROUGH 12Z WEDNESDAY AND WENT WITH AREAL QUALIFIER
WORDING. 00Z KAMA SOUNDING ALONG INDICATING LIFTED INDEX OF -3 AND
CAPE NEAR 1000 JOULES. NAM FORECASTING ANOTHER LOW LEVEL SOUTHERLY
JET OF 40 KNOTS SETTING UP BY 09Z WEDNESDAY...SIMILAR TO LAST NIGHT.
CANNOT COMPLETELY RULE OUT CONVECTION DEVELOPING ANYWHERE IN THE
FORECAST AREA OVERNIGHT TONIGHT. BUMPED UP WINDS TONIGHT SLIGHTLY AND
INCREASED SKY COVER. ALSO...UPDATED FIRE WEATHER GRIDS WITH THE
LATEST 00Z NAM DATA. CLEANED UP THE DISCUSSION IN THE FIRE WEATHER
FORECAST PRODUCT TO REMOVE CONTRACTIONS AND CHANGE FROM WIND SPEEDS
WORDING FROM KNOTS TO MPH. ALSO MENTIONED WIND SHIFT ASSOCIATED WITH
COLD FRONTAL PASSAGE WEDNESDAY NIGHT AND THURSDAY.
ALL PUBLIC AND FIRE WEATHER PRODUCTS HAVE BEEN UPDATED AND SENT.
SCHNEIDER
PREV DISCUSSION... /ISSUED 631 PM CDT TUE JUL 24 2012/
AVIATION...
SLOW-MOVING ISOLATED THUNDERSTORMS SEEN ON 88D AT THIS TIME DO NOT
APPEAR TO POSE THREAT TO TERMINALS THIS EVENING. WILL CONTINUE TO MONITOR.
OTHERWISE...SOUTHERLY SURFACE WINDS SHOULD CEASE GUSTING THIS
EVENING...AND THEN INCREASE AGAIN WEDNESDAY MORNING AS NOCTURNAL LOW-
LEVEL JET MIXES DOWNWARD. COLD FRONT WILL ENTER NORTHWEST PART OF
FORECAST AREA ON WEDNESDAY...BEING POISED NEAR KDHT AND KGUY DURING
THE HEAT OF THE DAY. KDHT AND KGUY WILL HAVE GREATER CHANCE TO BE
DIRECTLY IMPACTED BY SCATTERED THUNDERSTORMS FROM LATE AFTERNOON TO
EARLY EVENING WEDNESDAY...AS SHORTWAVE TROF PROVIDES ADDITIONAL LIFT.
VFR FORECAST CONTINUES NEXT 24 HOURS.
COCKRELL
PREV DISCUSSION... /ISSUED 323 PM CDT TUE JUL 24 2012/
DISCUSSION...
REGIONAL COMPOSITE RADAR SHOWS DEVELOPMENT OF THE SECOND ROUND OF
CONVECTION EXPECTED TO PERSIST INTO THE EVENING HOURS FOR THE SOUTHERN
PORTION OF THE CWA. ALSO BREEZY SURFACE WINDS OF 15 TO 20 KTS WITH
GUSTS UP TO 30 KTS HAVE DEVELOPED AS THE SURFACE GRADIENT ACROSS THE
PANHANDLES TIGHTENS.
REST OF TODAY AND TONIGHT...ANOTHER ROUND OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS EVENING AS AN UPPER LEVEL
WAVE CONTINUES A SSE TO NNW TRACK AROUND THE BASE OF THE UPPER LEVEL
RIDGE. WHILE THE SEVERE THREAT IS LOW WITH ANY CONVECTION THAT FORMS
THIS EVENING...BRIEF WIND GUSTS UP TO 45 MPH COULD BE EXPERIENCED
NEAR DECAYING CELLS. STORM ACTIVITY SHOULD END PRIOR TO MIDNIGHT AS
THE WAVE MOVES NORTH OF THE PANHANDLES.
WEDNESDAY THROUGH FRIDAY...THE STUBBORN UPPER LEVEL RIDGE BEGINS TO
BREAK DOWN EARLY WEDNESDAY MORNING AS AN UPPER LOW MOVES THROUGH
ALBERTA TOWARDS THE GREAT LAKES LOWERING THE HEIGHT FIELD ACROSS THE
NORTHERN AND CENTRAL PLAINS. THE RESULTING WEAKNESS IN THE RIDGE WILL
ALLOW A WEAK COLD FRONT TO DIVE INTO THE PANHANDLES WEDNESDAY AND
EXIT THE CWA FRIDAY. BREEZY CONDITIONS CAN BE EXPECTED WEDNESDAY IN
ADVANCE OF THE FRONT AS THE SURFACE GRADIENT TIGHTENS WITH SUSTAINED
15 TO 25 MPH SOUTHERLY WINDS AND OCCASIONAL GUSTS ABOVE 30 MPH. BY
MIDDAY WEDNESDAY RAIN CHANCES WILL RAISE AS THE APPROACHING FRONT
PROVIDES ADDITIONAL FORCING. THE SEVERE THREAT THROUGH FRIDAY WILL
REMAIN LOW DUE TO LOW CAPE VALUES GENERALLY AROUND 1500 J/KG AND THE
POOR DEFINITION OF THE FRONT. BRIEF DIURNAL BREAKS IN CONVECTIVE
ACTIVITY CAN BE EXPECTED EARLY THURSDAY AND FRIDAY MORNING BEFORE
REFORMING DURING THE DAY. THERE HAS BEEN SOME MODEL DISCONTINUITY
CONCERNING THE SPEED AT WHICH THE FRONT WILL MOVE THROUGH THE AREA.
THE NAM HAS BEEN THE MOST AGGRESSIVE AND PUSHES THE FRONT COMPLETELY
THROUGH THE AREA BY LATE THURSDAY, WHILE THE GFS KEEPS THE FRONT IN
THE CWA THROUGH LATE FRIDAY. THE ECMWF HAD BEEN TRENDING CLOSER TO
THE NAM PREVIOUSLY BUT HAS BEGUN TO TREND CLOSER TO THE GFS WITH TIME.
AS SUCH HAVE GONE WITH A BLEND OF THE GFS AND ECMWF OF THE SPEED OF
THE FRONT AND KEPT RAIN CHANCES THROUGH FRIDAY.
SATURDAY THROUGH WEDNESDAY...BY SATURDAY THE UPPER LEVEL RIDGE
STRENGTHENS TO END RAIN CHANCES FOR THE REST OF THE WEEK AND THROUGH
THE MIDDLE OF NEXT WEEK.
TEMPERATURES...STUCK CLOSE TO THE GFS MAXIMUM TEMPERATURES THROUGH
FRIDAY AND MINIMUM TEMPERATURES THROUGH THE FORECAST. LEANED CLOSER
TO THE ECMWF HIGH TEMPERATURE TOWARDS THE END OF THE FORECAST AS THE
GFS BEGAN TO TREND BACK TO CLIMO UNDER A STRENGTHENING RIDGE.
14
FIRE WEATHER...
STRONG SOUTHERLY WINDS ARE EXPECTED TO DIMINISH DURING THE EVENING
HOURS AS RELATIVE HUMIDITY VALUES BEGIN TO REBOUND. WILL SEE ANOTHER
ROUND OF STRONG SOUTHERLY 20-FT WINDS OF 15 TO 20 KTS WEDNESDAY
MAINLY IN THE NORTHEASTERN SECTIONS OF THE PANHANDLES. RELATIVE
HUMIDITY VALUES AT THAT TIME ARE EXPECTED TO DROP TO BELOW 25 PERCENT
BRIEFLY BEFORE REBOUNDING IN THE ADVANCE OF AN APPROACHING COLD
FRONT. THE INCREASED MOISTURE WILL PROMOTE ISOLATED TO SCATTERED
SHOWERS WEDNESDAY THROUGH FRIDAY. DRY AND HOT WEATHER IS EXPECTED TO
RETURN BY THE WEEKEND.
14
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/11
AREA FORECAST DISCUSSION
NWS SPOKANE WA
232 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...
Tonight: Slow moving thunderstorms will be our main focus this
evening. With very little wind in the lowest 10 thousand feet of
the model soundings, localized heavy rain will be the main impact
from storms through mid evening. Look for cells to be short lived,
but capable of producing heavy rain rates. This is typically what
we experience in a moderate instability and weak shear
environment.
The 2 PM radar imagery shows scattered showers and thunderstorms
over the high terrain near Mazama, Oroville, Republic and Curlew.
The RUC model suggests that the atmosphere is favorable for
development further south along the Cascade Crest down toward
Stevens and Stampede Pass with CAPE values approaching 1000 J/KG.
Increased convective development can also be expected over the
high terrain around Kettle Falls, Priest Lake and Bonners Ferry
through early evening. By late afternoon and early evening there
may be a better chance of getting some of the cells to survive
as they descend into the low elevations. But the heaviest rains
will likely fall over the mountains where storms are initiated
since they collapse quickly in the weak shear environment.
Overnight, there is a small chance of high based showers, mainly
south of the Spokane forecast area. The GFS and NAM show some
conditional instability mainly above 600mb. With a very dry
air mass from 700mb and below, any showers that develop will
probably not produce much measurable rain. The best elevated
instability on the NAM and GFS prior to sunrise will be over the
Oregon portion of the Columbia Basin. After sunrise the 600-500mb
negative theta-e lapse rates migrate over the Palouse into the
southern and central Idaho Panhandle. Chances for measurable
precipitation is very low, so I limited the precipitation chances
to 15 percent or less. We may need to add sprinkles into the
forecast if we see some high based showers develop on radar late
this evening. /GKoch
Thursday through Saturday...A prolonged period of southwest flow
due to the positioning of a long-wave trof off the coast juxtaposed
against ridge of high pressure with axis remaining somewhere in
Montana influences this time interval. Since the ridge to the east
is not all that well amplified and the southwest flow is not too
southerly in origin forecast temperatures remain very close to
normal. Additionally any mention of precipitation including
thunderstorms possibly fired off by small disturbances passing
through the discussed prevailing southwest to northeast flow remains
low but not zero given the weakness of the depicted disturbances.
There does appear to be enough moisture and energy though via a
ridge in the 700MB equivalent potential temperature fields running
through Eastern Oregon up into North Idaho...which is pretty much
aligned with the described prevailing southwest flow. The best
chance of any convection getting fired off is on Friday as that
wave has the best potential...but the pop still remains low. /Pelatti
Saturday night through Wednesday: Synoptic scale pattern will
remain stagnant as an expansive ridge of high pressure dominates
the central United States. This omega block pattern type will
prevent low pressure over the Gulf of Alaska to shift over the
Pac Northwest. We will remain under dry southwest flow between
this area of lower pressure to our west and higher pressure to our
east. There will be the possibility for some disturbances that
rotate around the Gulf of Alaska low that could impact the region.
However, moisture off the Pacific will be lacking, and without
much of a southerly component in the flow pattern, we will be hard
pressed to draw up any monsoonal moisture as well. Models are
picking up on a weak disturbance that moves through off the
Pacific on Sunday, which may produce some breezy winds. We may see
some more weak disturbances that move across the area next week,
but most of the energy associated with the low in the Gulf of
Alaska looks to stay to our north into British Columbia. Without
any discernible strong frontal systems with big air mass changes,
temperatures will be fairly consistent through the period. Expect
temperatures to be close to seasonal averages under clear or mostly
clear sky conditions. /SVH
&&
.AVIATION...
18Z TAFS: Some cumulus build ups over the mountains near the
Canadian border along with isolated showers and thunderstorms but
TAF sites should remain mostly clear with light winds through 18Z
Thursday. /Pelatti
&&
.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 / 10 10 10 20 20 0
Lewiston 64 95 66 94 63 91 / 10 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 / 10 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 / 10 0 0 0 10 0
Wenatchee 66 93 66 90 63 87 / 0 0 0 0 10 0
Omak 64 92 60 92 57 88 / 10 10 20 20 20 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1211 PM CDT WED JUL 25 2012
.UPDATE...
CIRRUS FROM THE STORMS TRACKING ACROSS NORTHERN WISCONSIN WILL
CONTINUE TO GRADUALLY THIN THROUGH EARLY AFTERNOON.
FURTHERMORE...HOT 925MB TEMPS 32C TO 34C WILL BE ADVECTING INTO
SOUTHERN WI LATE THIS AFTERNOON. SO DESPITE THE SLOW WARMING TREND
INTO THE 80S THIS MORNING...STILL EXPECTING A JUMP IN THE TEMPS BY 3
PM INTO THE UPPER 90S TO AROUND 100.
DEWPOINT TEMPS HAVE BEEN STEADILY INCREASING INTO THE LOWER 70S THIS
MORNING. WITH CAPPING INVERSION AND SURFACE TROUGH DRAPED ACROSS
CENTRAL WI...EXPECT THESE 70S DEWPOINTS TO POOL IN SOUTHEAST WI FOR
A GOOD PORTION OF THE AFTERNOON. AS WINDS BECOME SOUTHWESTERLY IN
THE WESTERN FORECAST AREA EARLY THIS AFTERNOON...EXPECT SOME
MODERATE MIXING OF DEWPOINTS BACK INTO THE MID 60S FOR A TIME.
DEWPOINTS WILL INCREASE ONCE AGAIN AS THE COLD FRONTAL BOUNDARY
APPROACHES.
SHOWERS DEVELOPED IN CENTRAL WI AS AN OUTFLOW BOUNDARY INTERSECTED A
GRAVITY WAVE. THE LIGHT SHOWERS ARE JUST ENTERING MARQUETTE COUNTY
AT THIS TIME.
MANY OF THE SMALL SCALE MODELS GENERATE A LINE OR CLUSTER OF
CONVECTION AROUND 21Z IN CENTRAL FORECAST AREA /CWA/...POSSIBLY
ALONG AN OUTFLOW BOUNDARY OR THAT GRAVITY WAVE. HOWEVER THE
ENVIRONMENT SHOULD BE TOO CAPPED TO ALLOW FOR ANY TYPE OF CONVECTION
AND WILL DISREGARD.
SOUTHERN WISCONSIN REMAINS IN THE SLIGHT RISK AREA. THE MAIN FOCUS
FOR THUNDERSTORMS WILL STILL BE LATE THIS AFTERNOON 23Z-00Z IN OUR
NW CWA AND APPROX 03Z IN THE CENTRAL FORECAST AREA AND 04Z IN THE
SOUTHEAST. IMPRESSIVE D-CAPE AROUND 1500 PER RAP MODEL THIS
AFTERNOON IN SOUTHERN WI. MAIN THREAT FOR SEVERE THUNDERSTORMS WILL
BE DAMAGING WINDS DUE TO THE DRY LOW LEVELS. DUE TO THE HIGHER
DEWPOINTS NOW...CAPE VALUES WILL BE 1500 TO 2000 J/KG THIS AFTERNOON
AND COMBINED WITH BULK SHEAR AROUND 30 TO 40 KNOTS WILL SUPPORT A
LARGE HAI THREAT AS WELL. WITH THE STRONG INSTABILITY AND SURFACE
HEATING...EXPECT STORMS TO FIRE UP PRETTY EASILY ALONG THE SURFACE
FRONT.
&&
.AVIATION/18Z TAFS/...
CIRRUS SHOULD GRADUALLY THIN THIS AFTERNOON. EXPECTING SCT TO
NUMEROUS THUNDERSTORMS TO DEVELOP IN WEST CENTRAL WI LATE THIS
AFTERNOON AND TRACK IN A LINE FORMATION SOUTHEASTWARD INTO
SOUTHEAST WI THIS EVENING ALONG A COLD FRONT. POTENTIAL FOR CIGS
TO LOWER TO MVFR UPON FRONTAL PASSAGE LATER TONIGHT.
THERE IS POTENTIAL FOR SEVERE THUNDERSTORMS THIS EVENING...WITH
THE MAIN THREAT OF STRAIGHT LINE DAMAGING WINDS.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT WED JUL 25 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
LOW LEVEL JET FEEDING MCS OVER CENTRAL MN PIVOTING MORE TO THE
NORTHEAST INTO NORTHERN WI AND THE UP AND AS A RESULT WEAKER THETA-E
ADVECTION FARTHER SOUTH TRIGGERING SCATTERED CONVECTION OVER SOUTHERN
WI. EXPECT THE CONVECTION TO DIMINISH IN THE EAST AFTER 12Z AS
STRONG ADVECTION SLIDES OFF TO THE EAST. BOTH NAM AND GFS SHOW DOWN
SLIGHTLY EWD MOVEMENT OF SFC LOW PRESSURE CURRENTLY OVER ERN SODAK.
HENCE A SLIGHT DELAY IN SOUTHEAST SFC WINDS BECOMING MORE SOUTH TO
SOUTHWESTERLY. DEWPTS HAVE REMAINED IN THE MID 50S TO LOW 60S
OVERNIGHT. EXPC DEWPTS TO INCREASE TODAY TO REFLECT HIGHER LOW
LEVEL RH TO THE SOUTH AND ADDED MOISTURE FROM SCT RECENT RAINFALL.
HOWEVER BETTER MIXING SHOULD RESULT IN KEEPING DEWPTS MORE IN THE
MIDDLE TO UPPER 60S...WITH A FEW AWOS SITES REMAINING IN THE 61 TO
65 RANGE. HIGHER DEWPTS LIKELY TO BE FARTHER NORTH...POOLING ALONG
APPROACHING SFC BOUNDARY.
00Z UPPER AIR ANALYSIS SHOWS LOW LEVEL ECMWF TEMPERATURES MORE IN
BALLPARK THAN VERY WARM NAM. HENCE EXPECTING 925H TEMPS TO WARM TO
31-32C WITH 850H TEMPS AROUND 24-25C THIS AFTN. WITH DRY ADIABATIC
LAPSE RATES SETTING UP THIS AFTERNOON...HOT AIR IN THE LOW LEVELS
SHOULD BE REALIZED...BUMPING UP TEMPERATURES TO AROUND 100 MANY
AREAS. COOLEST SPOTS LIKELY TO BE IN THE NORTH WHERE A BIT MORE
CLOUDINESS EXPECTED AND ALONG THE SHEBOYGAN AND OZAUKEE COUNTY
SHORELINES WHERE WINDS IN THESE AREAS WILL BE THE LAST TO TURN S TO
SW.
WL CONTINUE HEAT ADVISORY...BUT POSTPONE IT AN HOUR TO ACCOUNT FOR
DELAY IN APPARENT TEMPERATURES WARMING THROUGH THE 90S.
0 TO 6KM BULK SHEAR BORDERLINE SEVERE CRITERIA LATE THIS AFTERNOON
AND EVE AS SFC FRONT APPROACHES NORTHERN CWA. BY LATE
AFTERNOON...CIN ERASED WITH SFC BASED CAPES APPROACHING 2000J/KG IN
THE NORTH. CAN NOT RULE OUT SEVERE THREAT...ESPECIALLY WITH LOW
PRESSURE TRAVELING ALONG BOUNDARY INCREASING LOW LEVEL CONVERGENCE.
HOWEVER SOUTHWEST WINDS IN THE LOW LEVELS OF THE ATMOSPHERE A
NEGATIVE.
SHORT TERM GUIDANCE IN GOOD AGREEMENT ON CARRYING SFC LOW INTO LOWER
MI THUMB AREA. FAIRLY STRONG AREA OF LOW LEVEL FN VECTOR RESPONSE
TO FRONTOGENESIS SLIDES SOUTH ACROSS SOUTHERN WI DURING THE
EVENING...SO WL CONTINUE LIKELY WORDING WITH DIMINISHING TREND FROM
THE NORTHWEST AFT MIDNIGHT.
THURSDAY AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
KEPT SOME POPS ACROSS THE SOUTHEAST HALF OF THE FORECAST AREA
THURSDAY MORNING...AS THE ECMWF AND CANADIAN LINGER BETTER MOISTURE
AND FORCING WITH SHORTWAVE. COULD SEE A FEW MORE SHOWERS/STORMS
ACROSS THE FORECAST AREA LATER IN THE DAY AND OVERNIGHT AS A STRONGER
SHORTWAVE PUSHES THROUGH.
STILL THINKING THE SUN MAY POKE OUT FOR A TIME THURSDAY...SO BUMPED
HIGHS UP A BIT MORE PER 925 MB TEMPS IN THE 23-26C RANGE.
PRECIP MAY LINGER FRIDAY AS THE SLOWLY SHORTWAVE EXITS...WITH THE
BEST CHANCE ACROSS THE NORTHEAST. COOLER AIR ON THE BACKSIDE OF THE
WAVE SHOULD RETURN TEMPERATURES TO NEAR NORMAL VALUES.
SATURDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
A PLEASANT DAY EXPECTED SATURDAY...WITH HIGH PRESSURE BRINGING
PLENTY OF SUNSHINE TO GO ALONG WITH NEAR NORMAL TEMPERATURES.
SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE...MEDIUM
WITH UPPER RIDGE BUILDING IN TO THE WEST SUNDAY THROUGH
TUESDAY...COMBINATION OF WARM AIR ADVECTION AND A WEAK WAVE OR TWO
MAY KICK OFF SHOWERS/STORMS AT TIMES. WILL LIKELY SEE TEMPS WARM
BACK ABOVE NORMAL THROUGH THIS PERIOD.
AVIATION/12Z TAFS/...SCT T SHOULD END EARLY THIS MORNING AS STRONG
THETA-E ADVECTION SLIDES OFF TO THE EAST. VFR CONDITIONS EXPECTED
FOR MOST OF THE DAY. SCT TO NUMEROUS CONVECTION WL AFFECT SRN WI
TNGT AS SFC COLD FRONT AND MID-LEVEL DISTURBANCE MOVE THROUGH OUR
AREA. POTENTIAL FOR CIGS TO LOWER TO MVFR UPON FRONTAL PASSAGE LATER
TONIGHT.
MARINE...WILL CONTINUE SMALL CRAFT ADVY TODAY AS PRESSURE GRADIENT
TIGHTENS OVER LAKE MICHIGAN AHEAD OF LOW PRESSURE EXPECTED TO MOVE
INTO CENTRAL WI THIS AFTN. SOUTHEAST WINDS WL VEER SLIGHTLY TO
SOUTH LATER THIS MRNG AND AFTN. WINDS WL CONTINUE TO VEER TO THE
SOUTHWEST AND THEN TURN NORTH UPON FROPA TONIGHT. STILL A THREAT
FOR THUNDERSTORMS EARLY THIS MRNG WITH SCT CONVECTION DEVELOPING
LATER THIS AFTN AND EVE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR WIZ051-052-058>060-
062>072.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ046-047-056-057.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...MBK
THURSDAY THROUGH TUESDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
611 AM CDT WED JUL 25 2012
.SHORT TERM...TODAY THROUGH FRIDAY
259 AM CDT WED JUL 25 2012
FORECAST CONCERNS ARE ON DANGEROUS HEAT TODAY AND CHANCES FOR SEVERE
THUNDERSTORM THROUGH THIS EVENING. FOCUS THEN TURNS TO SHOWER AND
THUNDERSTORM CHANCES ON THURSDAY...WITH THE POTENTIAL FOR A FEW
ISOLATED SEVERE STORMS.
LATEST RADAR IMAGERY SHOWED WIDESPREAD SHOWERS AND THUNDERSTORMS
ACROSS CENTRAL AND NORTHERN MINNESOTA. SOME OF THESE STORMS HAVE
BECOME SEVERE...ORGANIZING INTO LINE STRUCTURES...AND CAPABLE OF
PRODUCING DAMAGING WINDS AND HEAVY RAINFALL.
THE ONGOING MCS ACROSS NORTHWEST AND NORTHERN WISCONSIN EARLY THIS
MORNING COULD POSSIBLY TURN EAST SOUTHEAST AND IMPACT LOCATIONS NORTH
OF INTERSTATE 94. THIS LINE OF STORMS WILL BE CAPABLE OF PRODUCING
DAMAGING WINDS.
OTHERWISE...HOT TEMPERATURES WILL BE SEEN ACROSS NORTHEAST
IOWA...SOUTHWEST WISCONSIN AND PORTIONS OF SOUTHEAST MINNESOTA
TODAY...WHERE HEAT INDEX VALUES WILL RANGE FROM 100 TO 105 THIS
AFTERNOON. ISOLATED AREAS OF HEAT INDICES OF 110 ARE POSSIBLE.
SURFACE LOW PRESSURE WILL MOVE INTO WESTERN SECTIONS OF SOUTHEAST
MINNESOTA LATE THIS MORNING. MEANWHILE...A WARM FRONT WILL BE IN
PLACE ACROSS NORTHERN WISCONSIN...JUST NORTH OF THE HIGHWAY 29
CORRIDOR...WHILE A COLD FRONT WILL EXTEND FROM NORTHWEST WISCONSIN
THROUGH SOUTH CENTRAL MINNESOTA INTO FAR NORTHEAST IOWA. THIS WILL
LEAVE MUCH OF THE FORECAST AREA IN THE WARM SECTOR WITH A PERIOD OF
SUNNY SKIES AND HOT TEMPERATURES SOUTH OF I-94. THE COLD FRONT
WILL PUSH SOUTHEAST INTO THE AREA THIS AFTERNOON. BREEZY SOUTHWEST
WINDS ARE EXPECTED TODAY AHEAD OF THE FRONT WITH WIND SPEEDS OF 15
TO 25 MPH WITH GUSTS IN THE 28 TO 35 MPH RANGE
POSSIBLE...ESPECIALLY ALONG THE BLUFF TOPS NEAR THE MISSISSIPPI
RIVER AND THE OPEN AREAS OF NORTHEAST IOWA AND SOUTHEAST
MINNESOTA.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT.
EXACTLY WHERE THE THE STORMS GO UP ALONG THE FRONT IS SOMEWHAT
UNCERTAIN WITH FORECAST MODELS VARYING ON THE EXACT LOCATION. THE
NAM SHOWS STORMS DEVELOPING ALONG A LINE EXTENDING FROM NEAR
WAUSAU WISCONSIN...TO NEAR LA CROSSE TO CHARLES CITY. THE
ECMWF...GFS...AND GEM SHOWS STORMS DEVELOPING FURTHER SOUTH OF THE
NAM MAINLY ACROSS NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN.
FORECAST SOUNDINGS CONTINUE TO SHOW INVERTED V TYPE SOUNDING THIS
AFTERNOON WITH DEEP MIXING EXPECTED UP TO 700 MB. IF THIS DEEP
MIXING IS REALIZED THERE WILL BE AN ENHANCED THREAT FOR DAMAGING
WINDS WITH ANY STORMS THAT DEVELOP. FEEL THE DEWPOINT MIXING MAY
BE A BIT OVERDONE WITH THE RECENT RAINS ACROSS PARTS OF THE AREA.
HOWEVER...LOCATIONS THAT HAVENT SEEN THESE RAINS MAY INDEED SEE
MIXING THIS DEEP. THE INSTABILITY COULD BE A BIT UNDERDONE WITH
DEWPOINTS MIXING OUT IN THE FORECAST SOUNDINGS. NOT CONSIDERING
THIS MIXING OUT...THE NAM SHOWS AFTERNOON 0-3 KM MUCAPE VALUES
INCREASING TO 3500 PLUS J/KG RIGHT ALONG THE BOUNDARY WITH
DEWPOINTS CLIMBING INTO THE UPPER 70S ALONG THE FRONT. DEEP LAYER
SHEAR LAGS BEHIND THE FRONT. THIS COULD HINDER STORM ORGANIZATION
FOR THIS AFTERNOON. HOWEVER...STILL CONCERNED ABOUT THE DRY LOW
LEVELS AND THE ENHANCED DAMAGING WIND THREAT IF THIS DEEP MIXING
OCCURS. THINKING THAT SOME OF THE STORMS WILL BECOME SEVERE THIS
AFTERNOON WITH DAMAGING WINDS THE MAIN THREAT AND POSSIBLY LARGE
HAIL IF DEEP LAYER SHEAR CAN CATCH UP TO THE FRONT.
THERE IS AN OUTSIDE CHANCE OF A BRIEF TORNADO THREAT ALONG THE
WARM FRONT EARLY THIS AFTERNOON BEFORE THE WARM FRONT EXITS THE
AREA. THIS IS ESPECIALLY THE CASE NEAR THE TRIPLE POINT OVER NORTH
CENTRAL WISCONSIN...NORTH OF INTERSTATE 94. THINKING THE CAP WILL
BE STRONG ENOUGH TO PREVENT SURFACE BASED CONVECTION BUT WILL HAVE
TO KEEP A VERY CLOSE EYE ON THIS. IF SURFACE BASED STORMS FORM
NEAR THE FRONT EARLY THIS AFTERNOON THERE WILL BE SUFFICIENT LOW
LEVEL SHEAR TO SUPPORT LOW LEVEL STORM ROTATION AND TORNADOES.
WILL HAVE TO KEEP A CLOSE WATCH ON THE EXACT TRACK OF THE SURFACE
LOW THIS MORNING. THE 00Z NAM IS THE ONLY MODEL SHOWING THE
SURFACE LOW STAYING THIS FAR SOUTH. THE ECMWF...GFS...AND GEM TAKE
THE LOW ACROSS FAR NORTHERN WISCONSIN. CONCERNED THAT THE ONGOING
CONVECTION THIS MORNING COULD HOLD THE WARM FRONT SOUTH AS THE NAM
IS SUGGESTING.
THE COLD FRONT WILL SLIDE SOUTHEAST OF THE REGION LATE THIS EVENING
TAKING WITH SHOWERS AND THUNDERSTORMS TAPERING OFF. SOME OF THE
STORMS COULD BE SEVERE THIS EVENING ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN WITH DAMAGING WINDS THE MAIN THREAT. AGAIN...IF
STORMS WOULD BECOME MORE ORGANIZED A FEW OF THEM COULD PRODUCE LARGE
HAIL. PLAN ON OVERNIGHT LOWS RANGING FROM THE LOWER 60S ACROSS
NORTHERN WISCONSIN TO AROUND 70 OVER NORTHEAST IOWA.
AN UPPER LEVEL TROUGH WILL DIVE INTO NORTHERN MINNESOTA THURSDAY
MORNING THEN MOVE SOUTHEAST INTO NORTHERN WISCONSIN THURSDAY
AFTERNOON. A WEAK COLD FRONT WILL PUSH ACROSS THE AREA AHEAD OF THE
APPROACHING TROUGH. SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE
FRONT AS UPPER LEVEL SUPPORT INCREASES WITH THE APPROACHING TROUGH.
SURFACE BASED CAPE INCREASES TO AROUND 1400 J/KG AHEAD OF THE FRONT.
0-6 KM SHEAR ISNT OVERLY IMPRESSIVE WITH VALUES RANGING FROM THE 25
TO 30 KTS. COULD SEE A FEW STRONG TO SEVERE STORMS AGAIN THURSDAY
AFTERNOON WITH DAMAGING WINDS AND POSSIBLY LARGE HAIL. PLAN ON HIGHS
ON THURSDAY RANGING FROM THE LOWER 80S ACROSS NORTHERN WISCONSIN TO
THE UPPER 80S OVER NORTHEAST IOWA.
COOLER AIR WILL MOVE INTO THE FORECAST AREA THURSDAY NIGHT INTO
FRIDAY WITH 850 MB TEMPERATURES FALLING INTO TE 12 TO 14 C RANGE BY
FRIDAY AFTERNOON. SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION
PROVIDING MOSTLY SUNNY SKIES. PLAN ON HIGH TEMPERATURES RANGING FROM
THE UPPER 70S OVER NORTHERN WISCONSIN TO THE LOWER 80S ACROSS
NORTHEAST IOWA.
.LONG TERM...SATURDAY THROUGH TUESDAY
259 AM CDT WED JUL 25 2012
25.00 MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON SATURDAY SHOWING
SURFACE HIGH PRESSURE IN CONTROL ACROSS THE FORECAST AREA...WITH
NORTHWEST FLOW ALOFT. PLAN ON MOSTLY SUNNY SKIES ON SATURDAY WITH
HIGHS IN THE 80S. A SHORTWAVE TROUGH WILL PUSH INTO THE UPPER
MISSISSIPPI RIVER VALLEY SATURDAY NIGHT THROUGH SUNDAY BRINGING A
CHANCE OF SHOWERS AND THUNDERSTORMS TO THE AREA. CHANCES FOR SHOWER
AND STORMS WILL PERSIST THROUGH TUESDAY AS WEAK EMBEDDED WAVES IN
THE NORTHWEST FLOW CONTINUE TO IMPACT THE REGION. FROM SUNDAY
THROUGH TUESDAY...PLAN ON HIGHS IN THE 80S TO AROUND 90 WITH
OVERNIGHT LOWS FALLING INTO THE 60S.
&&
.AVIATION...TODAY AND TONIGHT
610 AM CDT WED JUL 25 2012
HIGH LEVEL CLOUDS SPILLING OVER BOTH TAF SITES FROM THE ON GOING
MCS ACROSS NORTHERN MINNESOTA AND WISCONSIN. EXPECT THESE CLOUDS
WILL STAY AROUND FOR MUCH OF THE MORNING BEFORE DISSIPATING. THIS
WILL SLOW DOWN THE MIXING AND PUSHED BACK THE TIMING FOR THE WIND
GUSTS JUST A LITTLE BIT FROM THE PREVIOUS FORECASTS. 25.06Z NAM
BUFKIT SOUNDINGS STILL SHOWING A DEEP WELL MIXED LAYER BEHIND THE
WARM FRONT TODAY WITH SOUTHWEST WINDS AND GUSTS TO AROUND 25 KNOTS
OR SO. THE AREA OF LOW PRESSURE OVER EASTERN SOUTH DAKOTA WILL
MOVE EAST ALONG THE WARM FRONT TODAY BRINGING A COLD FRONT WITH
IT. EXPECTING SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG AND
BEHIND THE COLD FRONT ONCE THE STRONG CAP IN THE WARM SECTOR IS
BROKEN/DISPLACED. THE NAM STILL SUGGESTS THIS WILL OCCUR EAST OF
KRST BUT THE 25.08Z RUN OF THE HRRR IS SUGGESTING AT LEAST THE
POSSIBILITY OF SOME ACTIVITY AROUND KRST AND HONORED THIS WILL A
VCTS. KLSE HAS A MUCH BETTER CHANCE OF SEEING SOME STORMS AND WENT
WITH A 2 HOUR TEMPO PERIOD WHEN THE CHANCES SHOULD BE AT THEIR
HIGHEST. THE THREAT FOR THE CONVECTION SHOULD END 3 TO 4 HOURS
BEHIND THE COLD FRONT WITH THE WINDS COMING AROUND TO THE
NORTHWEST. MODEL SOUNDINGS AND GUIDANCE SHOWING THE LOWEST LEVELS
BECOMING SATURATED OVERNIGHT WITH FOG DEVELOPING. NOT SEEING ANY
OF THIS UPSTREAM BEHIND THE FRONT AT THIS TIME BUT DID CONTINUE
THE SCATTERED STRATUS DECK JUST IN CASE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
259 AM CDT WED JUL 25 2012
WI...HEAT ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
WIZ054-055-061.
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
WIZ041>044-053.
MN...HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
MNZ088-095-096.
IA...HEAT ADVISORY FROM NOON TODAY TO 9 PM CDT THIS EVENING FOR
IAZ010-011-018-019-029-030.
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR
IAZ008-009.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS MIAMI FL
133 AM EDT FRI JUL 27 2012
.AVIATION...VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD WITH
SEA BREEZES ALONG BOTH COASTS AFT 16Z. THERE COULD BE SOME
CONVECTION INTERIOR BUT IT WILL REMAIN WELL INLAND FROM THE TERMINALS.
KOB
&&
.PREV DISCUSSION... /ISSUED 955 PM EDT THU JUL 26 2012/
UPDATE...A FEW THUNDERSTORMS MANAGED TO DEVELOP OVER THE INTERIOR
DURING THE LATE AFTERNOON AND EVENING HOURS. THE EVENING MIAMI
SOUNDING SHOWS A PWAT OF ONLY 1.40 INCHES WITH VERY DRY AIR ABOVE
6K FT...BUT THERE WAS ENOUGH SEA/LAKE BREEZE CONVERGENCE AND
STRONG HEATING TO GET A FEW TSTORMS GOING. THE TSTORMS HAVE SINCE
DISSIPATED WITH JUST A FEW SHOWERS CONTINUING OVER THE RURAL
INTERIOR. TRANQUIL WEATHER WILL PREVAIL OVERNIGHT. NO SIGNIFICANT
CHANGES ARE NEEDED TO THE FORECAST AT THIS TIME. /GREGORIA
PREV DISCUSSION... /ISSUED 731 PM EDT THU JUL 26 2012/
AVIATION...
THE WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT OVER ALL OF THE
TAF SITES BETWEEN 01Z AND 03Z. THE EAST COAST TAF SITES WINDS WILL
THEN REMAINED LIGHT AND VARIABLE THROUGH 16Z...BEFORE SWINGING TO
A SOUTHEAST DIRECTION AND INCREASING TO AROUND 10 KTS. FOR KAPF
TAF SITE...THE WINDS WILL ALSO REMAIN LIGHT AND VARIABLE FRIDAY
UNTIL 15Z BEFORE SWINGING TO A WESTERLY DIRECTION AT 5 TO 10
KNOTS. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS
AT ALL OF THE TAF SITES TONIGHT THROUGH FRIDAY AFTERNOON.
AVIATION..54/BNB
PREV DISCUSSION... /ISSUED 324 PM EDT THU JUL 26 2012/
UPDATE...A SHOWER HAS RECENTLY DEVELOPED NEAR THE IMMOKALEE
AREA...AND THE CU FIELD IS MORE ESTABLISHED OVER SOUTH FL THIS
AFTERNOON COMPARED TO YESTERDAY. HRRR SHOWS ISOLATED ACTIVITY
DEVELOPING, BECOMING FOCUSED ACROSS THE LAKE OKEECHOBEE REGION.
THERE STILL WILL BE A STRUGGLE TO GET MUCH CONVECTION GOING THIS
AFTERNOON, DUE TO A CAP, BUT STRONG HEATING COULD ALLOW FOR
ISOLATED TSTORMS TO DEVELOP. SO ADDED THIS POSSIBILITY TO THE
FORECAST. /GREGORIA
PREV DISCUSSION... /ISSUED 237 PM EDT THU JUL 26 2012/
DISCUSSION...
THE LATEST GUIDANCE CONTINUES TO INDICATE THE DRIER AND STABLE
AIR MASS CURRENTLY ACROSS THE REGION SHOULD PREVAIL INTO AND
LIKELY THROUGH THE WEEKEND. AN AREA OF HIGH SURFACE PRESSURE JUST
TO THE EAST OF THE BAHAMAS IS FORECAST TO PERSIST INTO AND LIKELY THROUGH
THE WEEKEND. THIS WILL MAINTAIN A WEAKER PRESSURE GRADIENT ACROSS
THE REGION WITH WINDS 10 KNOTS OR LESS ACROSS THE REGIONAL WATERS
WITH THE EAST AND WEST COAST SEA BREEZES EXPECTED EACH DAY FRIDAY
AND THROUGH THE WEEKEND. LOW LEVEL AVAILABLE MOISTURE IS FORECAST
TO BE LIMITED THROUGH THE WEEKEND WITH MINIMAL CHANCE OF
CONVECTION AND PRECIP ACROSS THE REGION AND NONE CURRENTLY IN THE
FORECAST FOR THE NEXT SEVERAL DAYS.
THE LATEST GUIDANCE FOR DUST CONCENTRATIONS INDICATE SAHARAN DUST
CONTINUING ACROSS THE AREA AT LEAST THROUGH FRIDAY WITH HAZY
SKIES EXPECTED AND WILL LIKELY EXTEND INTO THE WEEKEND AS WELL.
MARINE...
A LIGHT SOUTHERLY TO SOUTHEASTERLY FLOW NEAR 10 KNOTS OR LESS
WILL PREVAIL ACROSS REGIONAL WATERS TONIGHT AND IS EXPECTED TO
CONTINUE THROUGH THE WEEKEND WITH MAINLY TRANQUIL SEAS FORECAST
FOR THE LOCAL GULF AND ATLANTIC WATERS TONIGHT THROUGH THE
WEEKEND.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1152 PM CDT THU JUL 26 2012
.AVIATION...
VFR CONDITIONS WILL BE OVER THE AREA THROUGH FRIDAY NIGHT. A WEAK
SURFACE TROF OVER THE AREA HAS ALLOWED WINDS TO BECOME LIGHT AND
VARIABLE. A FEW ISOLATED SHRA WERE OCCURRING NEAR THE TROF IN
SOUTHEAST IA AND OVER NW IL. THE TROF WILL MOVE SOUTHEAST
ALLOWING WINDS TO BECOME NORTHWEST AND INCREASE TO 6 TO 10KTS BY
FRIDAY MORNING AND THEN CONTINUING TO VEER TO THE NORTHEAST BY
FRIDAY EVENING. THE ISOLATED SHRA IS EXPECTED TO DISSIPATE WITHIN
THE NEXT SEVERAL HOURS.
DLF
&&
PREV DISCUSSION... /ISSUED 333 PM CDT THU JUL 26 2012/
SYNOPSIS...
12Z UA ANALYSIS HAS AN 850MB COLD FRONT FROM NORTHERN WISCONSIN
SOUTHWEST INTO THE OKLAHOMA PANHANDLE. SEVERAL TROFS WERE ACROSS
THE NORTHERN PLAINS BEHIND THE 850MB COLD FRONT. RADAR/SATELLITE
TRENDS THROUGH MID AFTERNOON SHOW DIURNAL CONVECTION HAS DEVELOPED
FROM SOUTHERN WISCONSIN INTO SOUTHEAST IOWA.
18Z SFC ANALYSIS HAS A FRONT/BOUNDARY FROM KVOK BACK TO KRSL. THIS
BOUNDARY MAY BE A VERY DIFFUSE COLD FRONT AS DEW POINTS QUICKLY
DROP INTO THE UPPER 50S AND LOWER 60S BEHIND THE BOUNDARY. AHEAD
OF THE FRONT/BOUNDARY DEW POINTS WERE IN THE LOW 70S.
SHORT TERM...TONIGHT AND FRIDAY
AN AREA OF DIFFERENTIAL HEATING ALONG THE FRONT/BOUNDARY HAS
ALLOWED CONVECTIVE TEMPERATURE TO BE ACHIEVED.
RAP TRENDS INDICATE THE CURRENT CONVECTION WILL REMAIN ISOLATED
OVER SOUTHEAST IOWA AND MORE SCATTERED FROM THE QUAD CITIES TO THE
NORTH AND EAST. RAP TRENDS INDICATE THIS CONVECTION WILL PERSIST
INTO THE LATE AFTERNOON AND EARLY EVENING IN THE FAR EASTERN AND
SOUTHERN SECTIONS OF THE CWFA.
THE APPROACHING SHORTWAVE ACROSS MINNESOTA IS ALLOWING CU TO
DEVELOP FROM SOUTHERN MINNESOTA INTO NORTHERN IOWA. RADAR SHOWS NO
CONVECTION AS YET BUT WITH PEAK HEATING OCCURRING CONVECTION MAY
DEVELOP IN THE NEXT COUPLE OF HOURS. IF THIS OCCURS...THEN IT MAY
GET INTO THE HWY 20 CORRIDOR THIS EVENING. NEARLY ALL CONVECTION
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNSET. HOWEVER...
CONVECTION DID PERSIST OVERNIGHT CLOSE TO THE SFC LOW AND UPPER
LOW. THUS IT IS POSSIBLE THAT SOME ISOLATED SHRA/TSRA MAY PERSIST
PAST MIDNIGHT THAT CATCHES THE NORTHEAST PART OF THE CWFA.
FRIDAY IS LOOKING TO BE QUITE NICE WITH TEMPERATURES NEAR NORMAL.
HUMIDITY LEVELS WILL ALSO BE LOW. ..08..
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
HIGH PRESSURE BUILDS INTO THE REGION FRIDAY NIGHT AND SATURDAY TO
KEEP THINGS QUIET BOTH PERIODS. HOWEVER...SATURDAY NIGHT AND SUNDAY
A NICE WARM AIR ADVECTION SURGE WITH A WEAK SHORTWAVE MOVES ACROSS
THE AREA TO BRING SOME PRECIPITATION CHANCES TO THE AREA.
TEMPERATURES WILL BE COOLER THAN WHAT WE HAVE HAD RECENTLY...WITH
HIGHS IN THE 80S TO AROUND 90 BOTH DAYS.
SUNDAY NIGHT THROUGH MONDAY NIGHT A STRONGER SHORTWAVE COMES ALONG
TO INTERACT WITH A WEAK 850MB BAROCLINIC ZONE TO BRING SOME
PRECIPITATION CHANCES TO THE AREA. THERE IS ROUGH AGREEMENT WITH
THE MODELS...BUT WITH TIMING DIFFERENCES TO ADD SOME CONFUSION.
HIGHS MONDAY TO BEGIN CREEPING UP...RISING INTO THE MID 80S TO LOW
90S.
TUESDAY THROUGH WEDNESDAY MODELS ARE IN GENERAL AGREEMENT THAT A
SURFACE RIDGE WILL BUILD ACROSS THE REGION...WHICH IS NOT ESPECIALLY
FAVORABLE FOR PRECIPITATION CHANCES...SO HAVE KEPT THOSE DRY OR AT
MOST SLIGHT CHANCE. HIGHS REMAIN IN THE 80S TO LOW 90S WITH THE
CONTINUING NORTHWEST FLOW ALOFT AND ENOUGH MOISTURE AT MID LEVELS TO
PRODUCE SOME MID CLOUDS.
THURSDAY WE HAVE A WEAK COLD FRONT AND HINTS AT AN UPPER LEVEL
SHORTWAVE TO MOVE THROUGH THE AREA...THOUGH MODELS HAVE A LOT OF
DIFFERENCES AND CONFIDENCE IS NOT VERY HIGH. HOWEVER...IT WAS
ENOUGH TO PUT IN TO CARRY SOME LOW END CHANCE POPS.
LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
158 AM EDT FRI JUL 27 2012
.UPDATE...
ISSUED AT 1250 AM EDT FRI JUL 27 2012
CLOUD TOPS HAVE REALLY STARTED TO WARM...SO THE THREAT INSIDE THE
WATCH AREA HAS QUICKLY DISAPPEARED. THUS...THE WATCH HAS BEEN
CANCELLED. STILL A THREAT FOR SOME FLOODING WITH THE HEAVY RAIN NORTH
OF I-64 ONGOING...BUT EVEN THIS THREAT WILL DIMINISH WITHIN AN HOUR
OR TWO. HRRR/RUC HAS MUCH OF THE ONGOING SHOWER/STORM ACTIVITY
FALLING APART...WHICH SEEMS SUPPORTIVE BASED ON THE LATEST RADAR
IMAGERY SHOWING THE LINE OF SHOWERS REALLY BREAKING UP AS THEY ENTER
THE I-75 CORRIDOR. STILL GOING TO CARRY SOME ISOLATED SHOWERS OR
STORMS FOR THE REST OF THE NIGHT AS THE COLD POOL COULD STILL IGNITE
A SHOWER OR TWO.
UPDATE ISSUED AT 1042 PM EDT THU JUL 26 2012
CONVECTION CONTINUES TO FIRE ALONG A MODEST LOW LEVEL JET OCCURRING
ACROSS KENTUCKY. THE SEVERE CONVECTION HAS BEEN GRADUALLY WINDING
DOWN NORTH OF I-64 OVERALL...ALTHOUGH A FEW CELLS CONTINUE TO GET
STRONG OCCASIONALLY. ALONG AND SOUTH OF THE MOUNTAIN PARKWAY...THE
AIR MASS HAS NOT BEEN TAPPED OUT YET...SO WILL HOLD ONTO THE WATCH.
SOME STORMS ARE TRAINING NORTH OF I-64 IN THE PAST HOUR...SO WILL
HAVE TO WATCH FOR THE POTENTIAL OF SOME MINOR FLOODING IN POOR
DRAINAGE AREAS. DEEPER CONVECTION IS ALSO FIRING UP ACROSS CENTRAL
KENTUCKY...AND THIS CONTINUES TO SLOWLY SAG SOUTH WITH TIME...WHILE
INDIVIDUAL CELLS AND CLUSTERS MOVE EAST. DO EXPECT A GRADUAL WEAKENING
TREND AS THEY HEAD TOWARDS I-75...SO LOCALLY HEAVY RAINFALL MAY BE
THE BIGGEST THREAT FROM THESE BY THE TIME THEY MAKE IT INTO THE AREA
AFTER MIDNIGHT.
UPDATE ISSUED AT 741 PM EDT THU JUL 26 2012
STRONG TO SEVERE CONVECTION HAS MADE IT INTO THE I-64 CORRIDOR...WITH
MORE TRAILING CONVECTION OFF TO WSW. SO FAR...THIS LINE HAS ONLY
SAGGED SOUTHEAST SLIGHTLY IN THE PAST HOUR...HOWEVER THIS MAY MAKE
BETTER PROGRESS IN THE NEXT FEW HOURS IF COLD POOLING CAN GET GOING.
HAVE UPDATED THE FORECAST TO INCLUDE CATEGORICAL POPS IN THE
BLUEGRASS...AND THEN BLENDED INTO THE EXISTING TIMING FOR NOW UNTIL
IT BECOMES MORE CLEAR IF THE STORMS MAKE MORE OF A SOUTHEAST SAG WITH
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM EDT THU JUL 26 2012
CHALLENGING FORECAST FOR THE SHORT TERM. BEST DYNAMICS AND FORCING REMAIN
TO THE NORTH OF OUR AREA AT THIS TIME...BUT WITH CONTINUED INSOLATION
FOR SEVERAL MORE HOURS AIR MASS OVER EAST KY WILL CONTINUE TO
DESTABILIZE. LATEST GOES SOUNDER SHOWS LIFTED INDICES FROM -3 TO -5
OVER AREA...AND PLENTY OF LOW LEVEL MOISTURE IS IN PLACE WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S.
HOWEVER THE WINDOW FOR SEVERE WEATHER IN EAST KY LOOKS VERY LIMITED
DUE TO TIMING OF WHEN CONVECTION SHOULD ENTER THE AREA. BEST ESTIMATE
AT THIS TIME IS FOR CONVECTION TO ENTER THE FAR NORTH AROUND 8 PM.
WITH BEST FORCING REMAINING NORTH OF THE AREA AND THE FACT THAT WE
WILL BE LOSING DAYTIME HEATING DO NOT EXPECT CONVECTION THAT ENTERS
OUR AREA TO MAINTAIN SEVERE CHARACTERISTICS...IF IT IS SEVERE TO
BEGIN WITH...VERY FAR SOUTH AND EAST INTO THE FORECAST AREA.
THERE IS ALSO A WIDE RANGE OF MODEL SOLUTIONS FOR THE NEAR
TERM AS TO TIMING AND EXTENT OF SHOWERS AND THUNDERSTORMS TONIGHT AND
AGAIN ON FRIDAY INTO FRIDAY EVENING. FOR THE VERY NEAR TERM HAD BEEN
FAVORING THE HRRR WHICH HAD BEEN VERY CONSISTENT WITH SEVERAL RUNS IN
A ROW SHOWING THE SHOWERS AND THUNDERSTORMS MOVING INTO THE FAR
NORTH PART OF OUR AREA AROUND 01Z. HOWEVER THE LATEST...15Z RUN IS
KEEPING MOST OF OUR AREA DRY THROUGH 06Z. FOR NOW HAVE GONE WITH A
BLEND OF NEIGHBORING FORECAST OFFICE TIMING...CURRENT RADAR
TRENDS...ANALYSIS AND MODEL BLENDS.
ALL CONVECTION TONIGHT WILL BE PRE FRONTAL...AND WITH THE FRONT YET
TO PUSH INTO OUR AREA ON FRIDAY...ADDITIONAL THUNDERSTORMS WILL BE
POSSIBLE YET AGAIN...AS UPPER SHORT WAVE TROF MOVES ACROSS THE LAKES
AND OH VALLEY. THE 12Z NAM IS THE MOST AGGRESSIVE WITH THIS
IDEA...AND SPC HAS PLACED OUR ENTIRE AREA IN A SLIGHT RISK FOR
FRIDAY. THERE IS CONSIDERABLE QUESTION AS TO HOW MUCH INSTABILITY
WILL BE PRESENT ON FRIDAY THOUGH. WILL CARRY THUNDERSTORM CHANCES ON
FRIDAY FOR ONGOING MORNING CONVECTION AND ALSO CHANCE FOR
REDEVELOPMENT IN THE AFTERNOON...AND WILL CARRY SLIGHT CHANCE TO
CHANCE INTO FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU JUL 26 2012
THE PERIOD WILL BEGIN WITH AN UPPER LEVEL SHORTWAVE TROUGH PUSHING
EAST OF THE AREA WITH RISING HEIGHTS ACROSS THE REGION ON SAT. UPPER
LEVEL RIDGING WILL GENERALLY DOMINATE THE WEEKEND WITH SFC HIGH
PRESSURE BUILDING INTO THE OHIO VALLEY BEFORE SHIFTING EAST AT THE
END OF WEEKEND. HOWEVER...BY EARLY NEXT WEEK THE RIDGE BECOME
ESTABLISHED A BIT FURTHER SOUTHWEST IN THE SOUTHERN PLAINS WITH THE
REGION ENDING UP IN NW FLOW ALOFT BETWEEN THIS RIDGE AND TROUGHING
OVER THE GREAT LAKES...NORTHEAST AND DOWN ALONG THE EASTERN
SEABOARD. THIS OVERALL PATTERN WILL REMAIN UNCHANGED TROUGH THE END
OF THE PERIOD.
THIS SCENARIO WILL LEAD TO A RATHER QUIET AND PLEASANT PATTERN OVER
THE WEEKEND AND YIELD MORE ACTIVE WEATHER WITH THE THREAT OF
CONVECTION. THIS CONVECTION SHOULD LARGELY HAVE A DIURNAL COMPONENT
TO IT...BUT MCS NOCTURNAL CONVECTION WILL ALSO BE POSSIBLE. TIMING OF
THE THE GREATEST THREAT OF NOCTURNAL CONVECTION IS LOW ATTM...ALTHOUGH
MODELS TO POINT TOWARD SOME OF THIS POSSIBLY OCCURRING ON MON NIGHT.
WE WENT WITH SLIGHT CHANCE POPS IN THE SW LATE ON SUN NIGHT WITH
CHANCE POPS WITH THE DIURNAL FLAVOR FROM THEN ON.
AS FOR TEMPS...MAX TEMPS SHOULD AVERAGE NEAR NORMAL THROUGH THE
PERIOD...WITH THE GREATEST DEPARTURE IN OVERNIGHT LOWS FROM TUE NIGHT
ON. MIN T ON SAT NIGHT...IN THE LOW TO MID 60S MAY BE THE LOWEST
OBSERVED SO FAR THIS MONTH IN VALLEY LOCATIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 157 AM EDT FRI JUL 27 2012
COLD POOL HAS PUSHED ACROSS THE TAF SITES WITH A BRIEF GUSTS TO
AROUND 20 TO 25 KNOTS. THE RAIN CHANCES WILL COME TO AN END OVER THE
NEXT 30 TO 40 MINUTES. WITHOUT MUCH RAINFALL AT THE TAF
SITES...REALLY NOT ANTICIPATED MUCH FOG OVERNIGHT. VFR CONDITIONS
WILL THEN DOMINATE THROUGH MUCH OF FRIDAY. A COLD FRONT DROPPING IN
FROM THE NORTH TOMORROW EVENING WILL BRING ANOTHER CHANCE FOR SHOWERS
AND STORMS AFTER 00Z TOMORROW EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM....JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1250 AM EDT FRI JUL 27 2012
.UPDATE...
ISSUED AT 1250 AM EDT FRI JUL 27 2012
CLOUD TOPS HAVE REALLY STARTED TO WARM...SO THE THREAT INSIDE THE
WATCH AREA HAS QUICKLY DISAPPEARED. THUS...THE WATCH HAS BEEN
CANCELLED. STILL A THREAT FOR SOME FLOODING WITH THE HEAVY RAIN NORTH
OF I-64 ONGOING...BUT EVEN THIS THREAT WILL DIMINISH WITHIN AN HOUR
OR TWO. HRRR/RUC HAS MUCH OF THE ONGOING SHOWER/STORM ACTIVITY
FALLING APART...WHICH SEEMS SUPPORTIVE BASED ON THE LATEST RADAR
IMAGERY SHOWING THE LINE OF SHOWERS REALLY BREAKING UP AS THEY ENTER
THE I-75 CORRIDOR. STILL GOING TO CARRY SOME ISOLATED SHOWERS OR
STORMS FOR THE REST OF THE NIGHT AS THE COLD POOL COULD STILL IGNITE
A SHOWER OR TWO.
UPDATE ISSUED AT 1042 PM EDT THU JUL 26 2012
CONVECTION CONTINUES TO FIRE ALONG A MODEST LOW LEVEL JET OCCURRING
ACROSS KENTUCKY. THE SEVERE CONVECTION HAS BEEN GRADUALLY WINDING
DOWN NORTH OF I-64 OVERALL...ALTHOUGH A FEW CELLS CONTINUE TO GET
STRONG OCCASIONALLY. ALONG AND SOUTH OF THE MOUNTAIN PARKWAY...THE
AIR MASS HAS NOT BEEN TAPPED OUT YET...SO WILL HOLD ONTO THE WATCH.
SOME STORMS ARE TRAINING NORTH OF I-64 IN THE PAST HOUR...SO WILL
HAVE TO WATCH FOR THE POTENTIAL OF SOME MINOR FLOODING IN POOR
DRAINAGE AREAS. DEEPER CONVECTION IS ALSO FIRING UP ACROSS CENTRAL
KENTUCKY...AND THIS CONTINUES TO SLOWLY SAG SOUTH WITH TIME...WHILE
INDIVIDUAL CELLS AND CLUSTERS MOVE EAST. DO EXPECT A GRADUAL WEAKENING
TREND AS THEY HEAD TOWARDS I-75...SO LOCALLY HEAVY RAINFALL MAY BE
THE BIGGEST THREAT FROM THESE BY THE TIME THEY MAKE IT INTO THE AREA
AFTER MIDNIGHT.
UPDATE ISSUED AT 741 PM EDT THU JUL 26 2012
STRONG TO SEVERE CONVECTION HAS MADE IT INTO THE I-64 CORRIDOR...WITH
MORE TRAILING CONVECTION OFF TO WSW. SO FAR...THIS LINE HAS ONLY
SAGGED SOUTHEAST SLIGHTLY IN THE PAST HOUR...HOWEVER THIS MAY MAKE
BETTER PROGRESS IN THE NEXT FEW HOURS IF COLD POOLING CAN GET GOING.
HAVE UPDATED THE FORECAST TO INCLUDE CATEGORICAL POPS IN THE
BLUEGRASS...AND THEN BLENDED INTO THE EXISTING TIMING FOR NOW UNTIL
IT BECOMES MORE CLEAR IF THE STORMS MAKE MORE OF A SOUTHEAST SAG WITH
TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM EDT THU JUL 26 2012
CHALLENGING FORECAST FOR THE SHORT TERM. BEST DYNAMICS AND FORCING REMAIN
TO THE NORTH OF OUR AREA AT THIS TIME...BUT WITH CONTINUED INSOLATION
FOR SEVERAL MORE HOURS AIR MASS OVER EAST KY WILL CONTINUE TO
DESTABILIZE. LATEST GOES SOUNDER SHOWS LIFTED INDICES FROM -3 TO -5
OVER AREA...AND PLENTY OF LOW LEVEL MOISTURE IS IN PLACE WITH
DEWPOINTS IN THE LOWER TO MIDDLE 70S.
HOWEVER THE WINDOW FOR SEVERE WEATHER IN EAST KY LOOKS VERY LIMITED
DUE TO TIMING OF WHEN CONVECTION SHOULD ENTER THE AREA. BEST ESTIMATE
AT THIS TIME IS FOR CONVECTION TO ENTER THE FAR NORTH AROUND 8 PM.
WITH BEST FORCING REMAINING NORTH OF THE AREA AND THE FACT THAT WE
WILL BE LOSING DAYTIME HEATING DO NOT EXPECT CONVECTION THAT ENTERS
OUR AREA TO MAINTAIN SEVERE CHARACTERISTICS...IF IT IS SEVERE TO
BEGIN WITH...VERY FAR SOUTH AND EAST INTO THE FORECAST AREA.
THERE IS ALSO A WIDE RANGE OF MODEL SOLUTIONS FOR THE NEAR
TERM AS TO TIMING AND EXTENT OF SHOWERS AND THUNDERSTORMS TONIGHT AND
AGAIN ON FRIDAY INTO FRIDAY EVENING. FOR THE VERY NEAR TERM HAD BEEN
FAVORING THE HRRR WHICH HAD BEEN VERY CONSISTENT WITH SEVERAL RUNS IN
A ROW SHOWING THE SHOWERS AND THUNDERSTORMS MOVING INTO THE FAR
NORTH PART OF OUR AREA AROUND 01Z. HOWEVER THE LATEST...15Z RUN IS
KEEPING MOST OF OUR AREA DRY THROUGH 06Z. FOR NOW HAVE GONE WITH A
BLEND OF NEIGHBORING FORECAST OFFICE TIMING...CURRENT RADAR
TRENDS...ANALYSIS AND MODEL BLENDS.
ALL CONVECTION TONIGHT WILL BE PRE FRONTAL...AND WITH THE FRONT YET
TO PUSH INTO OUR AREA ON FRIDAY...ADDITIONAL THUNDERSTORMS WILL BE
POSSIBLE YET AGAIN...AS UPPER SHORT WAVE TROF MOVES ACROSS THE LAKES
AND OH VALLEY. THE 12Z NAM IS THE MOST AGGRESSIVE WITH THIS
IDEA...AND SPC HAS PLACED OUR ENTIRE AREA IN A SLIGHT RISK FOR
FRIDAY. THERE IS CONSIDERABLE QUESTION AS TO HOW MUCH INSTABILITY
WILL BE PRESENT ON FRIDAY THOUGH. WILL CARRY THUNDERSTORM CHANCES ON
FRIDAY FOR ONGOING MORNING CONVECTION AND ALSO CHANCE FOR
REDEVELOPMENT IN THE AFTERNOON...AND WILL CARRY SLIGHT CHANCE TO
CHANCE INTO FRIDAY NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM EDT THU JUL 26 2012
THE PERIOD WILL BEGIN WITH AN UPPER LEVEL SHORTWAVE TROUGH PUSHING
EAST OF THE AREA WITH RISING HEIGHTS ACROSS THE REGION ON SAT. UPPER
LEVEL RIDGING WILL GENERALLY DOMINATE THE WEEKEND WITH SFC HIGH
PRESSURE BUILDING INTO THE OHIO VALLEY BEFORE SHIFTING EAST AT THE
END OF WEEKEND. HOWEVER...BY EARLY NEXT WEEK THE RIDGE BECOME
ESTABLISHED A BIT FURTHER SOUTHWEST IN THE SOUTHERN PLAINS WITH THE
REGION ENDING UP IN NW FLOW ALOFT BETWEEN THIS RIDGE AND TROUGHING
OVER THE GREAT LAKES...NORTHEAST AND DOWN ALONG THE EASTERN
SEABOARD. THIS OVERALL PATTERN WILL REMAIN UNCHANGED TROUGH THE END
OF THE PERIOD.
THIS SCENARIO WILL LEAD TO A RATHER QUIET AND PLEASANT PATTERN OVER
THE WEEKEND AND YIELD MORE ACTIVE WEATHER WITH THE THREAT OF
CONVECTION. THIS CONVECTION SHOULD LARGELY HAVE A DIURNAL COMPONENT
TO IT...BUT MCS NOCTURNAL CONVECTION WILL ALSO BE POSSIBLE. TIMING OF
THE THE GREATEST THREAT OF NOCTURNAL CONVECTION IS LOW ATTM...ALTHOUGH
MODELS TO POINT TOWARD SOME OF THIS POSSIBLY OCCURRING ON MON NIGHT.
WE WENT WITH SLIGHT CHANCE POPS IN THE SW LATE ON SUN NIGHT WITH
CHANCE POPS WITH THE DIURNAL FLAVOR FROM THEN ON.
AS FOR TEMPS...MAX TEMPS SHOULD AVERAGE NEAR NORMAL THROUGH THE
PERIOD...WITH THE GREATEST DEPARTURE IN OVERNIGHT LOWS FROM TUE NIGHT
ON. MIN T ON SAT NIGHT...IN THE LOW TO MID 60S MAY BE THE LOWEST
OBSERVED SO FAR THIS MONTH IN VALLEY LOCATIONS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 741 PM EDT THU JUL 26 2012
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH MOST OF THE
EVENING...AS ONGOING CONVECTION ALONG THE I-64 CORRIDOR LOOKS TO STAY
NORTH FOR A WHILE. SOUTHWEST WINDS WILL CONTINUE TO GUST IN THE
BROADER VALLEYS TO BETWEEN 15 AND 20 KTS THIS EVENING...BEFORE
DIMINISHING. THUNDERSTORMS ARE THEN EXPECTED TO ADVANCE ACROSS THE
FORECAST AREA FROM NORTH TO SOUTH DURING THE OVERNIGHT
PERIOD...ALTHOUGH CONFIDENCE IS NOT VERY HIGH WITH HOW MUCH THEY WILL
HOLD TOGETHER. ASSUMING THUNDERSTORMS DO HOLD TOGETHER...EXPECT IFR
TO MVFR CONDITIONS IN FOG AND LOW CLOUDS TO PERSIST INTO THE DAY ON
FRIDAY...WITH SCATTERED THUNDERSTORMS POSSIBLE ONCE AGAIN DURING THE
AFTERNOON HOURS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM....JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
339 AM EDT FRI JUL 27 2012
.SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
&&
.MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.AVIATION...ISSUED 118 AM EDT FRI JUL 27 2012
//DISCUSSION...
POCKETS OF LOWER STRATUS CONTINUE TO EMERGE WITHIN THE POST-FRONTAL
LOW LEVEL NORTHEAST FLOW LATE THIS EVENING. THIS TREND WILL LIKELY
PERSIST THROUGH THE NIGHT...WITH THE FRONTAL BOUNDARY POSITIONED
JUST THE WEST. LOWEST CEILINGS WILL TEND TO EXIST ACROSS THE
NORTHERN TAF SITES...WHERE CONDITIONS WILL AT LEAST INTERMITTENTLY
DIP INTO MVFR /IFR AT PTK THANKS TO THE ELEVATION/. PROSPECTS FOR
SOME AREAS OF FOG STILL EXIST GIVEN THE MOIST BOUNDARY LAYER
CONDITIONS. THE HIGHER DEGREE OF CLOUD COVERAGE...AND PERHAPS SOME
PERSISTENCE IN THE LOW LEVEL GRADIENT FLOW...WOULD SEEMINGLY DETER A
MORE WIDESPREAD/THICKER FOG ISSUE. THE GROWING MID LEVEL
INSTABILITY ATTENDANT TO AN APPROACHING WAVE WILL ALLOW
PRECIPITATION TO INCREASE IN COVERAGE THROUGH THE DAY ON FRIDAY.
STILL A BIT EARLY TO PROVIDE SPECIFIC TIMING ON THUNDERSTORM
POTENTIAL.
EXPANDING AREA OF PRECIPITATION ON FRIDAY.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET AT LEAST
INTERMITTENTLY ON FRIDAY...BUT LOW CONFIDENCE ON TIMING.
* MEDIUM CONFIDENCE IN THUNDERSTORM DEVELOPMENT ON FRIDAY...BUT LOW
CONFIDENCE IN TIMING AND LOCATION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
AVIATION.....MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1126 PM CDT THU JUL 26 2012
.UPDATE...
ISSUED AT 730 PM CDT THU JUL 26 2012
HAVE EXPANDED THE MENTION OF ISOLATED SHOWERS AND THUNDERSTORMS
FURTHER SOUTH TOWARD CENTRAL PORTIONS OF THE CWA THIS EVENING. A
BROKEN LINE OF CONVECTION EXTENDING FROM NORTH CENTRAL MISSOURI
AND INTO CENTRAL ILLINOIS CONTINUES TO DRIFT SOUTHWARD...THOUGH
GIVEN INDICATIONS FROM HRRR MODEL OUTPUT AND THE LOSS OF DAYTIME
HEATING...THE EXPECTATION IS FOR THESE STORMS TO TAPER OFF THROUGH
THE LATE EVENING HOURS.
OTHERWISE...GOING FORECAST REMAINS ON TRACK WITH ONLY MINOR
CHANGES TO SHORT TERM TRENDS NEEDED FOR AREAS CO-LOCATED WITH
CONVECTION THIS EVENING.
PHILLIPSON
&&
.SYNOPSIS...
ISSUED AT 216 PM CDT THU JUL 26 2012
591DAM HIGH AT 500MB HAS SPLIT INTO TWO CENTERS...ONE LOCATED
ACROSS ARIZONA AND THE OTHER OVER LOUISIANA. IN BETWEEN...THE WELL
ADVERTISED TROF OF LOW PRESSURE EXTENDS FROM LAKE SUPERIOR TO
TEXAS.
OVERNIGHT MCS DISSIPATED ON SCHEDULE AS IT ENCOUNTERED THE REMAINING
RIDGE AXIS THAT AT 12Z WAS STILL POKING UP ALONG THE MISSISSIPPI
RIVER. THINNING CLOUD COVER AND VERY WARM 850MB TEMPERATURES ABOVE
20C RESULTED IN TEMPERATURES JUMPING BACK INTO THE 90S. TRUE SURFACE
COLD FRONT IS JUST NOW ENTERING THE NORTHWEST CORNER OF THE
CWA...BUT DEEP CONVECTION IS FIRING ALONG AND SOUTH OF THE OUTFLOW
BOUNDARY (SOUTHERN MISSOURI AND ILLINOIS).
CVKING
&&
.SHORT TERM...
ISSUED AT 216 PM CDT THU JUL 26 2012
(TONIGHT THROUGH SUNDAY)
COLD FRONT WILL MAKE STEADY PROGRESS SOUTH ACROSS THE CWA...WITH
FOCUS FOR DEEP CONVECTION QUICKLY MOVING SOUTH AND EAST OF THE CWA
THIS EVENING. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH DEWPOINTS
SLOW TO FALL BEHIND THE FRONT.
DEEP MIXING...ABOVE 800 MB...WILL RESULT IN ANOTHER HOT DAY ON
FRIDAY FOR MOST OF THE CWA. ONLY EXCEPTION IS FAR NORTH THAT WILL
ONLY BE MIXING MIDDLE/UPPER TEEN TEMPERATURES FROM 850MB RATHER THAN
+20C. WILL BE EXTENDING HEAT HEADLINES ONE MORE DAY WITH FORECAST
HIGHS IN THE UPPER 90S TO 100 DEGREES. DEEP MIXING WILL SEND
DEWPOINTS TANKING IN THE AFTERNOON DUE TO DRIER AIR ALOFT BEHIND THE
FRONT. HEAT INDEX VALUES WILL NOT REACH OFFICIAL CRITERIA...BUT DONT
WANT TO SEND THE WRONG MESSAGE...WE HAVE ONE MORE HOT DAY BEFORE
COOLER AIR FILTERS IN FOR SATURDAY.
AREA MAY EXPERIENCE RED FLAG CONDITIONS TOMORROW AFTERNOON...GIVEN
DROUGHT CONDITIONS...LOW RELATIVE HUMIDITY AND NORTHWEST WINDS. WILL
LET MIDSHIFT DETERMINE THE NEED FOR THE HEADLINE BASED ON LATEST
MODEL DATA AND RAINFALL REPORTS.
850MB THERMAL AXIS SHIFTS FURTHER TO THE WEST ON SATURDAY WITH
COOLER...YET STILL ABOVE NORMAL...TEMPERATURES EXPECTED. WITH DEEP
MIXING AND PLENTY OF SUNSHINE HAVE FORECAST HIGHS A DEGREE OR TWO
WARMER THAN THE WARMEST MET MOS.
PROSPECT FOR PRECIPITATION DOES INCREASE SATURDAY NIGHT AND SUNDAY
AS MODELS PORTRAY NOCTURNAL CONVECTION DEVELOPING ACROSS THE CENTRAL
PLAINS ON THE NOSE OF A LOW LEVEL JET. HAVE INCREASED CLOUD COVER
AND POPS SATURDAY NIGHT AND SUNDAY ACROSS NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS WHERE DECAYING CONVECTION WOULD PROPAGATE. IF
THIS OCCURS...TEMPERATURES MAY END UP COOLER THAN CURRENTLY FORECAST
FOR SUNDAY.
CVKING
&&
.LONG TERM...
ISSUED AT 216 PM CDT THU JUL 26 2012
(MONDAY THROUGH THURSDAY)
MODELS AGREE THAT AN ACTIVE NORTHWEST FLOW PATTERN WILL SET UP
ACROSS THE AREA FOR THE REMAINDER OF THE FORECAST AS THE UPPER LEVEL
RIDGE EXPANDS ACROSS THE ROCKIES/PLAINS AND A TROF DEEPENS OVER THE
EAST COAST. PINNING DOWN PRECIPITATION CHANCES IN THIS TYPE OF A
PATTERN IS VERY DIFFICULT DUE TO THE TIMING/TRACK OF WEAK
SHORTWAVES. TO ADD SALT TO THE WOUND...MODEL GUIDANCE HAS BEEN FAR
TOO ROBUST WITH PRECIPITATION DEVELOPMENT THE PAST FEW MONTHS DUE TO
THE EXTREME DROUGHT CONDITIONS. THEREFORE WILL REMAIN VERY
CONSERVATIVE IN FORECASTING PRECIPITATION IN THE EXTENDED PERIODS OF
THE FORECAST.
TEMPERATURES WILL REMAIN ABOVE NORMAL WITH EXACT VALUES BEING HIGHLY
DE PENDANT ON THE SURFACE FRONTAL POSITION...CLOUD COVER AND ANY
PRECIPITATION THAT IS OBSERVED. 850MB TEMPERATURES RANGE FROM THE
LOWER 20S ACROSS CENTRAL MISSOURI TO THE UPPER TEENS IN CENTRAL
ILLINOIS...WHICH SUPPORTS SURFACE TEMPERATURES NEAR 100 DEGREES IN
CENTRAL MISSOURI AND MIDDLE 90S IN CENTRAL ILLINOIS. DEWPOINTS MAY
POOL NEXT WEEK WITH THE CLOSE PROXIMITY OF THE FRONTAL POSITION AND
LEAD TO HEAT INDEX VALUES RISING BACK ABOVE 100 DEGREES AT TIMES.
CVKING
&&
.AVIATION...
ISSUED AT 1126 PM CDT THU JUL 26 2012
STORMS CONTINUE TO FIREUP OVER NORTHEAST MO/WEST CENTRAL IL AND
SLIDE SOUTHEAST AHEAD OF COLD FRONT...BUT DISSIPATE BEFORE
REACHING INTERSTATE 70. RECENT CLUSTER TRIED TO MOVE INTO
KUIN...BUT DIMINISHED BEFORE REACHING TAF SITE. SO CONFIDENCE IS
LOW THAT THIS CURRENT ACTIVITY WILL REACH METRO AREA...SO WILL
LEAVE TAFS DRY FOR NOW.
OTHERWISE...WINDS WILL BE LIGHT AND VARIABLE THROUGH 14Z-15Z BEFORE
COLD FRONT MOVES ACROSS THE AREA. NORTHWEST TO NORTH WINDS BETWEEN
10 AND 15KTS TO PERSIST ACROSS FORECAST AREA TODAY BEFORE
DIMINISHING ONCE AGAIN THIS EVENING.
SPECIFICS FOR KSTL...ANOTHER BATCH OF STORMS TO THE NORTHWEST OF
METRO AREA CONTINUES TO SLOWLY DIMINISH AS IT MOVES SOUTHEAST...SO
CONFIDENCE IS LOW THAT IT WILL REACH KSTL. SO KEPT TAF DRY FOR
NOW. OTHERWISE...WINDS WILL BE LIGHT AND VARIABLE THROUGH 15Z
BEFORE COLD FRONT MOVES ACROSS THE AREA. NORTHWEST WINDS NEAR 15KTS
TO PERSIST ACROSS METRO AREA TODAY BEFORE DIMINISHING ONCE
AGAIN BY 01Z SATURDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR AUDRAIN MO-BOONE MO-
CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-MONITEAU MO-
MONTGOMERY MO-OSAGE MO-PIKE MO-REYNOLDS MO-ST. FRANCOIS MO-
STE. GENEVIEVE MO-WARREN MO-WASHINGTON MO.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT FRIDAY FOR ST. CHARLES MO-
ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR BOND IL-CALHOUN IL-
CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-
MARION IL-MONROE IL-MONTGOMERY IL-RANDOLPH IL-WASHINGTON IL.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT FRIDAY FOR MADISON IL-ST.
CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1241 AM CDT FRI JUL 27 2012
.AVIATION...
WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
WEST OF MRR-IML LATE FRIDAY AFTERNOON. THE SHOWERS AND ISOLATED
THUNDERSTORMS WILL THEN SPREAD INTO PARTS OF NORTH CENTRAL TO
SOUTHWEST NEBRASKA AFTER 00Z WITH THE HIGHEST COVERAGE NORTH AND
WEST OF ANW-LBF-OGA. HOWEVER...WITH COVERAGE LESS THAN 20 PERCENT IN
CENTRAL AND SOUTHWEST NEBRASKA AND LESS THAN 40 PERCENT IN NORTH
CENTRAL AND NORTHWEST NEBRASKA...IT WILL NOT BE INCLUDED IN THE
TERMINAL FORECASTS FOR VTN OR LBF. LIGHT AND VARIABLE WINDS
OVERNIGHT BECOMING SOUTHEAST FRIDAY AFTERNOON ON THE BACKSIDE OF THE
SURFACE HIGH AND INCREASING TOWARD SUNSET FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 903 PM CDT THU JUL 26 2012/
UPDATE...
UPDATED TO REMOVE ISOLATED THUNDERSTORMS.
AVIATION...
VISUAL FLIGHT RULES EXPECTED OVER WESTERN NEBRASKA THROUGH FRIDAY AFTERNOON.
PREV DISCUSSION... /ISSUED 621 PM CDT THU JUL 26 2012/
UPDATE...
UPDATED FORECAST TO EXPAND THUNDERSTORM AREA.
PREV DISCUSSION... /ISSUED 406 PM CDT THU JUL 26 2012/
DISCUSSION...
A FAIRLY STRONG COLD FRONT ACROSS SD THIS AFTN IS PROGGED TO DROP
THROUGH SWRN NEB THIS EVENING AND BECOME STATIONARY ALONG THE KS
BORDER FRIDAY MORNING. THE FRONT...MARGINAL INSTABILITY...STRONG
SHEAR...30 TO 40 KTS OF BULK SHEAR RESULTING IN BULK RICHARDSON
NUMBER NEAR 25 AND SFC DEW POINTS IN THE LOWER 50S SUGGEST ISOLATED
HIGH BASED STORM COVERAGE SHOULD ANYTHING FORM. BOTH THE HRRR AND
RAP13 ARE VERY AMBITIOUS SHOWING SCATTERED STORM COVERAGE FROM 20Z
ONWARD.
THE FRONT WILL LIFT NORTH INTO NCNTL NEB FRIDAY AND ACT AS A FOCUS
FOR ISOLATED LATE AFTN AND EVENING HIGH BASED TSTMS GIVEN LOW SFC
DEW POINTS. TEMPS ALONG AND WEST OF HIGHWAY 83 SHOULD RECOVER WITH
HIGHS IN THE MID AND UPPER 90S.
INCREASING LOW LEVEL FLOW...DEEPENING LOW PRESSURE ACROSS THE NRN
HIGH PLAINS AND VERY DEEP MOISTURE ABOVE 700 MB IS EXPECTED TO
PRODUCE A ROUND OF SCATTERED HIGH BASED TSTMS...POSSIBLY PRODUCING
WIND DAMAGE AS THEY MOVE EAST ACROSS THE FCST AREA FRIDAY NIGHT
INTO SATURDAY MORNING. THIS AREA OF STORMS MOVES TO NEAR KOMA BY
12Z SATURDAY AND THE WARM FRONT ADVANCES NORTH AND EAST TO NEAR
KONL/KYKN SATURDAY AFTERNOON. HIGHS SATURDAY SHOULD BE ABLE TO
REACH 100F AS H10-5 THICKNESSES RISE TO NEAR 590 DM. MORE ISOLATED
DIURNALLY DRIVEN HIGH BASED TSTMS ARE EXPECTED TO DEVELOP LATE SATURDAY.
ANOTHER WEAK BACK DOOR COLD FRONT WILL MOVE THROUGH SATURDAY
NIGHT. THIS FRONT WOULD APPEAR TO WASH OUT ACROSS SRN NEB SUNDAY.
BY NOW A HEAT LOW HAS ESTABLISHED ITSELF ACROSS WRN KS/ERN COLO.
THIS LOW COULD STILL PRODUCE TEMPS NEAR 100F AS BOTH THE NAM AND
GEM SHOW H10-5 THICKNESSES APPROACHING 590 DM ACROSS WRN NEB. THE
GENERAL CONSENSUS AMONG THE MODELS WAS FOR ANOTHER UPPER LEVEL
DISTURBANCE TO MOVE THROUGH LATE SUNDAY SUNDAY NIGHT.
MONDAY THROUGH THURSDAY...
THE DROUGHT RIDGE IS FCST BY ALL MODELS TO REMAIN STATIONARY AND
CENTER OVER ERN NM/NW TX. THIS COULD PLACE THE FCST AREA IN THE
RING OF FIRE PROVIDED AMPLE MOISTURE IS AVAILABLE. THE ECM AND GFS
850-300MB MOISTURE SUPPORT THIS BUT FCST QPF IN BOTH MODELS IS
DRY. SO DRY WEATHER IS EXPECTED WITH HIGHS AT LEAST IN THE 90S. H7
TEMPS ARE EXPECTED TO RUN 10C TO 14C WHICH SHOULD PRODUCE UPPER
90S. NOTE THE EXTREME DROUGHT CONDITIONS MAY SUPPORT HIGHS AROUND
100 BUT NOT NEARLY AS WARM AS WE SAW EARLIER THIS MONTH.
FIRE WEATHER...
ALL THUNDERSTORM ACTIVITY WILL BE CLOSELY MONITORED DURING THE
NEXT 7 DAYS FOR SIGNS OF DRY LIGHTNING AND POTENTIAL WILD FIRES.
STORM COVERAGE IS EXPECTED TO BE LESS THAN 25 PERCENT IN ANY ONE
PARTICULAR FIRE WEATHER ZONE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT THU JUL 26 2012
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK
CDFNT CURRENTLY MOVG THROUGH THE OMA/LNK TAF SITES AND WILL CONT TO
THE SOUTH. PRESSURE RISES BEHIND THE FNT WILL KEEP SOME NORTH WIND
UP THROUGH THE NIGHT AND THROUGH THE DAY ON FRIDAY. LITTLE IN THE
WAY OF CLOUD COVER IS EXPECTED THROUGH THE NEXT 24 HOURS...ALTHOUGH
A FEW LATE MRNG/AFTN CU WILL BE POSSIBLE AT OMA /WHICH IS A BIT
CLOSER TO THE LOW LEVEL MOIST CYCLONIC FLOW OVER IA/MN/ BUT WL LEAVE
ALL THE TAFS CLR ATTM THRU 06Z SAT.
BOUSTEAD
&&
.DISCUSSION...
SMALL CHANCE FOR PRECIPITATION TONIGHT...THEN THUNDERSTORM CHANCES
FRIDAY NIGHT THROUGH MONDAY...ARE THE PRIMARY FORECAST CONCERNS.
SECONDARY COOL FRONT WAS DROPPING THROUGH THE CWA THIS AFTERNOON.
TEMPERATURES WERE SIMILAR ON BOTH SIDES OF THE BOUNDARY...BUT DEW
POINTS DRIED CONSIDERABLY BEHIND THE FRONT. DEW POINTS WERE IN THE
THE 50S IN NORTHEAST NEBRASKA AS OF 2 PM...WHILE SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA HAD DEW POINTS BETWEEN 65 AND 70. INSTABILITY
WAS INCREASING IN THIS AREA WITH MOST UNSTABLE CAPE VALUES TOPPING
3000 J/KG. LOW LEVEL CONVERGENCE WAS RATHER WEEK AS WINDS ONLY
TURNED FROM WEST TO NORTHWEST AHEAD AND BEHIND FRONT. AND MID
LEVEL LAPSE RATES WERE RATHER TIMID AS WELL. STILL CUMULUS FIELD
WAS BUBBLING UP IN CYCLONIC FLOW IN EAST CENTRAL NEBRASKA AND WEST
CENTRAL IOWA. NAM...GFS AND HRRR ALL SUGGEST SOME CONVECTION WILL
FIRE IN THE UNSTABLE AIR OVER SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA LATE THIS AFTERNOON AND EVENING. GIVEN INSTABILITY AND WEAK
CONVERGENCE ALONG FRONT...PLUS THE FACT THAT RETURNS ARE SHOWING
UP ON RADAR...WILL INSERT ISOLATED STORMS THIS AFTERNOON AND
EVENING IN THOSE AREAS.
STORMS SHOULD MOVE OUT OR DISSIPATE RATHER QUICKLY BY
SUNSET...LEAVING MOSTLY CLEAR SKIES AND DIMINISHING WINDS AS
SURFACE HIGH PRESSURE SETTLES IN OVERNIGHT. THAT HIGH AND A
REDUCTION IN 850 TEMPS BY 5C OR SO WILL LEAD TO COOLER
TEMPERATURES FRIDAY. HAVE HIGHS FROM THE MIDDLE 80S NORTH TO NEAR
90 SOUTH FRIDAY AFTERNOON WITH LIGHT NORTH OR NORTHEAST WINDS.
AS THE HIGH SHIFTS EAST FRIDAY NIGHT...RETURN FLOW BEGINS AS
SHORTWAVE MOVES OFF THE HIGH PLAINS INTO THE REGION. MODELS HAVE
BEEN ADVERTISING THIS THE LAST SEVERAL DAYS...AND ARE NOW CONVERGING
ON A TRACK THROUGH SOUTH DAKOTA AND INTO SOUTHEAST SOUTH DAKOTA BY
12Z SATURDAY. THIS WILL SHIFT AXIS OF ASSOCIATED PRECIPITATION NORTH
OF OUR CURRENT FORECAST...WITH HIGHEST POPS ALONG THE SOUTH DAKOTA
BORDER. WILL MAINTAIN SMALL POPS SOUTHWARD AT LEAST TO INTERSTATE 80
LATE FRIDAY NIGHT AND SATURDAY MORNING WHERE HIGHER THETA-E AIR WILL
RIDE NORTH. AREA SHOULD LIFT TO THE NORTHEAST SATURDAY AFTERNOON AND
WILL MAINTAIN SMALL POPS IN OUR FAR NORTHEAST THEN.
A SIMILAR SITUATION WILL OCCUR SATURDAY NIGHT INTO SUNDAY AS ANOTHER
SHORTWAVE ROLLS THROUGH THE NORTHERN PLAINS. BOTH GFS AND ECMWF SHOW
THIS WAVE A BIT FARTHER NORTH THAN FRIDAY NIGHT WAVE...BUT
MOISTURE...LOW LEVEL JET AND ELEVATED INSTABILITY WILL ALL BE MORE
CONDUCIVE FOR SCATTERED OVERNIGHT CONVECTION. THUS WILL KEEP OUR
SMALL POPS FOR MOST OF THE CWA WITH HIGHEST CHANCES AGAIN IN THE
NORTH AND NORTHEAST.
SURFACE FRONT WILL TRAIL THIS SECOND WAVE AND SETTLE ACROSS THE CWA
SUNDAY NIGHT AND MONDAY. GFS AND ECMWF TRIGGER PRECIPITATION ALONG
THIS BOUNDARY AS YET ANOTHER SHORTWAVE DROPS THROUGH NORTHWEST FLOW
ALOFT...BUT EACH MODEL HAS A SLIGHTLY DIFFERENT TRACK.
WILL KEEP OUR DRY AND WARMER FORECAST GOING THROUGH MID WEEK AS
UPPER RIDGE TRIES TO BUILD BACK INTO THE REGION. MODELS ARE A LITTLE
LESS BULLISH ON BRINGING THIS INTO THE PLAINS...POSSIBLY ALLOWING
MORE SHORTWAVES TO DROP INTO THE REGION BRINGING SPORADIC PRECIP
CHANCES.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1153 PM CDT THU JUL 26 2012
.UPDATE...
LOWERED POPS TO CHANCE OVERNIGHT. MAIN AREA OF PCPN HEADING INTO
THE NORTHERN PLATEAU ATTM. ANOTHER WARM DAY ON FRI WITH MORE
MOISTURE FOR AFTN STORMS SOUTH AND PLATEAU.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT THU JUL 26 2012/
UPDATE...
00Z TAF DISCUSSION.
AVIATION...
QLCS HAS DEVELOPED FROM N AR TO SW IN AND MOVING SOUTHEASTWARD
TOWARDS MID TN...WITH ISOLATED TSRA DEVELOPING IN FRONT OF THE
LINE AS WELL. LATEST LAPS ANALYSIS SHOWS A STRONG INSTABILITY
AXIS FROM SW TO NE ACROSS THE MID STATE WITH CAPES OF 2500-3000
J/KG...AND HRRR GUIDANCE INDICATES LINE WILL SURVIVE AND AFFECT
CKV AROUND 02Z BUT WEAKEN AS IT APPROACHES BNA AND CSV LATER
TONIGHT. WILL SHOW MAIN TSRA IMPACTS AT CKV THIS EVENING WITH
GUSTS TO 30 KTS AND IFR VIS POSSIBLE...AND STRATIFORM TSRA/SHRA
BEHIND THE MAIN LINE THROUGH THE EARLY MORNING HOURS. LESSER
IMPACTS EXPECTED WITH WEAKENING LINE AT BNA AND CSV WITH VCTS OR
TEMPO TSRA. BREAK IN ACTIVITY EXPECTED FRIDAY MORNING BEFORE
REDEVELOPMENT BY AFTERNOON ACROSS MIDDLE TENNESSEE WITH COLD FRONT
MOVING ACROSS.
PREV DISCUSSION... /ISSUED 623 PM CDT THU JUL 26 2012/
UPDATE...
SEVERE STORMS ASSOC WITH UNSTAB ATM AND H5 TROF DIGGING SOUTH OVR
THE OHVLY. LATEST MODELS DROP ANOTHER S/W TROF IN THE SOUTHERN
PLAINS MOVG SOUTHEAST. THIS SHOULD KEEP STORM ACTIVITY STRONG TO
SEVERE THIS EVENING...AS SYSTEM SPREADS INTO NORTHWEST CORNER OF
MID-TN BTW 8 AND 9 PM.
PREV DISCUSSION... /ISSUED 351 PM CDT THU JUL 26 2012/
DISCUSSION...
CAP ACROSS THE MID STATE IN A HOLDING PATTERN FOR NOW. COULD STILL
SEE SOME ISOL DEVELOPMENT THROUGH THIS EVENING. OTW...A FRONTAL
BOUNDARY IS LOCATED TO OUR NORTH ACROSS CENTRAL IL WITH BETTER
CONVECTION COVERAGE ALONG AND JUST SOUTH OF THIS FEATURE.
FOR TONIGHT...SHOULD SEE A 1-2 PUNCH IN TERMS OF CONVECTION CHANCES.
ISOLATED ACTIVITY IS EXPECTED THROUGH THIS EVENING. THEN...AS THE
AFOREMENTIONED FRONTAL BOUNDARY SINKS SOUTHWARD...A BETTER CHANCE
OF SHOWERS AND TSTMS WILL COMMENCE SOMETIME AROUND MIDNIGHT.
OVERNIGHT CAPE VALUES ARE QUITE IMPRESSIVE AND SINCE GRAPHICAL DEW
POINTS LOOK REASONABLE...STRONG TO PERHAPS SEVERE STORMS WILL BE
POSSIBLE. LATEST 3 HR PRESSURE CHANGE IN SUPPORT OF THE SOUTHWARD
MOVING BOUNDARY.
PRECIP PROBABILITIES WILL NOT BE ALL THAT HIGH TONIGHT AND TUESDAY.
MODELS ARE CONSISTENT WITH A RATHER NARROW RELATIVE DEEP MOISTURE
PROFILE. POPS WILL BE HELD DOWN INTO THE 30-50 PERCENT RANGE TONIGHT
AND FRIDAY.
CAPE VALUES WILL REMAIN ELEVATED THROUGH THE DAY ON FRIDAY. SO
AGAIN...STRONG TO SEVERE STORMS WILL BE POSSIBLE.
DRIER AIR WILL FINALLY WORK INTO THE AREA FRIDAY NIGHT. THIS DRY
PATTERN WILL EXTEND INTO THE FIRST PORTION OF THE EXTENDED FCST.
FOR THE SHORT TERM TEMPS...ABOVE NORMAL TEMPS TO CONTINUE BUT WE
WILL SEE MORE OF A DIURNAL RANGE THIS WEEKEND.
ADDITIONALLY...DEWPOINTS WILL LOWER INTO THE 60S FOR SATURDAY AND
SUNDAY...SO NICE WEEKEND COMING UP.
FOR THE EXT FCST...UPPER HIGH TO HOLD OVER TX AND THIS WILL KEEP
MIDDLE TN UNDER A NW FLOW REGIME. AFTER A DRY PERIOD THIS
WEEKEND...DISTURBANCES AND AN INCREASE IN MOISTURE WILL TRANSLATE
THE PATTERN INTO MORE OF AN ACTIVE NW FLOW. WILL THEREFORE INCLUDE A
CHANCE OF SHOWERS AND TSTMS BEGINNING ON TUESDAY. OTW...TEMPS TO
REMAIN ABOVE NORMAL. STILL A REASONABLE CHANCE THAT THIS JULY WILL
END UP BEING THE 2ND WARMEST ON RECORD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1151 PM CDT THU JUL 26 2012
.UPDATE...
06Z TAF DISCUSSION.
&&
.AVIATION...
GUST FRONT CURRENTLY STRETCHES SW TO NE ACROSS THE MIDDLE OF THE
CWA WITH SCATTERED SHRA/TSRA BEHIND THE BOUNDARY. INTERMITTENT
-SHRA WILL AFFECT CKV/BNA FOR A COUPLE MORE HOURS BEFORE ACTIVITY
DIES OFF...WHILE VCTS IS ANTICIPATED AT CSV WITH GUST FRONT
PASSAGE OVERNIGHT. ALL CONVECTION TO DISSIPATE BY SUNRISE WITH
SOME MVFR FOG POSSIBLE AT CKV DUE TO THE HEAVY RAINFALL EARLIER.
ADDITIONAL SHRA/TSRA EXPECTED BY FRIDAY AFTERNOON AS COLD
FRONT/DRIER AIR ALOFT FILTERS SOUTHWARD INTO THE MID STATE...WITH
VCTS AT BNA/CSV.
&&
.PREV DISCUSSION... /ISSUED 700 PM CDT THU JUL 26 2012/
UPDATE...
00Z TAF DISCUSSION.
AVIATION...
QLCS HAS DEVELOPED FROM N AR TO SW IN AND MOVING SOUTHEASTWARD
TOWARDS MID TN...WITH ISOLATED TSRA DEVELOPING IN FRONT OF THE
LINE AS WELL. LATEST LAPS ANALYSIS SHOWS A STRONG INSTABILITY
AXIS FROM SW TO NE ACROSS THE MID STATE WITH CAPES OF 2500-3000
J/KG...AND HRRR GUIDANCE INDICATES LINE WILL SURVIVE AND AFFECT
CKV AROUND 02Z BUT WEAKEN AS IT APPROACHES BNA AND CSV LATER
TONIGHT. WILL SHOW MAIN TSRA IMPACTS AT CKV THIS EVENING WITH
GUSTS TO 30 KTS AND IFR VIS POSSIBLE...AND STRATIFORM TSRA/SHRA
BEHIND THE MAIN LINE THROUGH THE EARLY MORNING HOURS. LESSER
IMPACTS EXPECTED WITH WEAKENING LINE AT BNA AND CSV WITH VCTS OR
TEMPO TSRA. BREAK IN ACTIVITY EXPECTED FRIDAY MORNING BEFORE
REDEVELOPMENT BY AFTERNOON ACROSS MIDDLE TENNESSEE WITH COLD FRONT
MOVING ACROSS.
PREV DISCUSSION... /ISSUED 623 PM CDT THU JUL 26 2012/
UPDATE...
SEVERE STORMS ASSOC WITH UNSTAB ATM AND H5 TROF DIGGING SOUTH OVR
THE OHVLY. LATEST MODELS DROP ANOTHER S/W TROF IN THE SOUTHERN
PLAINS MOVG SOUTHEAST. THIS SHOULD KEEP STORM ACTIVITY STRONG TO
SEVERE THIS EVENING...AS SYSTEM SPREADS INTO NORTHWEST CORNER OF
MID-TN BTW 8 AND 9 PM.
PREV DISCUSSION... /ISSUED 351 PM CDT THU JUL 26 2012/
DISCUSSION...
CAP ACROSS THE MID STATE IN A HOLDING PATTERN FOR NOW. COULD STILL
SEE SOME ISOL DEVELOPMENT THROUGH THIS EVENING. OTW...A FRONTAL
BOUNDARY IS LOCATED TO OUR NORTH ACROSS CENTRAL IL WITH BETTER
CONVECTION COVERAGE ALONG AND JUST SOUTH OF THIS FEATURE.
FOR TONIGHT...SHOULD SEE A 1-2 PUNCH IN TERMS OF CONVECTION CHANCES.
ISOLATED ACTIVITY IS EXPECTED THROUGH THIS EVENING. THEN...AS THE
AFOREMENTIONED FRONTAL BOUNDARY SINKS SOUTHWARD...A BETTER CHANCE
OF SHOWERS AND TSTMS WILL COMMENCE SOMETIME AROUND MIDNIGHT.
OVERNIGHT CAPE VALUES ARE QUITE IMPRESSIVE AND SINCE GRAPHICAL DEW
POINTS LOOK REASONABLE...STRONG TO PERHAPS SEVERE STORMS WILL BE
POSSIBLE. LATEST 3 HR PRESSURE CHANGE IN SUPPORT OF THE SOUTHWARD
MOVING BOUNDARY.
PRECIP PROBABILITIES WILL NOT BE ALL THAT HIGH TONIGHT AND TUESDAY.
MODELS ARE CONSISTENT WITH A RATHER NARROW RELATIVE DEEP MOISTURE
PROFILE. POPS WILL BE HELD DOWN INTO THE 30-50 PERCENT RANGE TONIGHT
AND FRIDAY.
CAPE VALUES WILL REMAIN ELEVATED THROUGH THE DAY ON FRIDAY. SO
AGAIN...STRONG TO SEVERE STORMS WILL BE POSSIBLE.
DRIER AIR WILL FINALLY WORK INTO THE AREA FRIDAY NIGHT. THIS DRY
PATTERN WILL EXTEND INTO THE FIRST PORTION OF THE EXTENDED FCST.
FOR THE SHORT TERM TEMPS...ABOVE NORMAL TEMPS TO CONTINUE BUT WE
WILL SEE MORE OF A DIURNAL RANGE THIS WEEKEND.
ADDITIONALLY...DEWPOINTS WILL LOWER INTO THE 60S FOR SATURDAY AND
SUNDAY...SO NICE WEEKEND COMING UP.
FOR THE EXT FCST...UPPER HIGH TO HOLD OVER TX AND THIS WILL KEEP
MIDDLE TN UNDER A NW FLOW REGIME. AFTER A DRY PERIOD THIS
WEEKEND...DISTURBANCES AND AN INCREASE IN MOISTURE WILL TRANSLATE
THE PATTERN INTO MORE OF AN ACTIVE NW FLOW. WILL THEREFORE INCLUDE A
CHANCE OF SHOWERS AND TSTMS BEGINNING ON TUESDAY. OTW...TEMPS TO
REMAIN ABOVE NORMAL. STILL A REASONABLE CHANCE THAT THIS JULY WILL
END UP BEING THE 2ND WARMEST ON RECORD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS DENVER CO
947 AM MDT FRI JUL 27 2012
.UPDATE...LATEST WATER VAPOR IMAGERY SHOWS MID/UPPER LEVEL
MOISTURE INCREASING ACROSS THE WESTERN TWO THIRDS OF COLORADO
THIS MORNING. INTEGRATED PRECIPIATABLE WATER FROM GPS INDICATES
READINGS WERE ABOUT 0.25 INCH HIGHER THAN YESTERDAY ON THE WEST
SLOPE. THIS MOISTURE WILL SPILL OVER THE TOP OF THE RIDGE TODAY SO
CURRENT FORECAST IS ON TRACK WITH INCREASED STORM COVERAGE THIS
AFTERNOON/EVENING...WITH THE BEST COVERAGE IN THE MOUNTAINS.
LATEST SHORT RANGE MODELS INCLUDING THE HRRR AND RAP SHOW A LITTLE
HIGHER STORM COVERAGE ON THE PLAINS AS WELL. ANY STORMS WILL BE
HIGH BASED SO THREAT OF GUSTY WINDS WITH STORMS IS HIGH ENOUGH TO
WARRANT INCLUSION IN THE LATEST FORECAST.
&&
.AVIATION...STORM COVERAGE IS EXPECTED TO BE A LITTLE HIGHER
TODAY WITH INCREASING MID/HIGH LEVEL MOISTURE. THAT ALONG WITH DRY
SUBCLOUD LAYER SHOULD RESULT IN A RELATIVELY HIGH CHANCE OF GUSTY
OUTFLOW WINDS ASSOCIATED WITH ANY STORMS THAT PUSH OFF THE
FOOTHILLS. WILL GO FOR A PREVAILING STRONGER WESTERLY OUTFLOW WIND
STARTING 20Z-21Z WHICH IS CLOSER TO CLIMATOLOGY IN THESE
SITUATIONS. CHANCE OF STORMS WILL OCCUR FROM 20Z-03Z WITH BEST
CHANCE 21Z-01Z.
&&
.PREV DISCUSSION... /ISSUED 352 AM MDT FRI JUL 27 2012/
SHORT TERM...UPPER LEVEL RIDGE WILL BE CENTERED OVER COLORADO AND
NEW MEXICO TODAY. THIS WILL RESULT IN WEAK FLOW ALOFT OVER THE
STATE. MOISTURE TO INCREASE TODAY...MAINLY OVER THE HIGHER TERRAIN
WHERE PRECIPITABLE WATER VALUES WILL BE A HALF TO THREE QUARTERS OF
AN INCH. JUST A SLIGHT INCREASE ACROSS THE URBAN CORRIDOR AND
EASTERN PLAINS WITH PRECIPITABLE WATER VALUES HOVER JUST BELOW AN
INCH. THIS INCREASE IN MOISTURE AND WEAKENING OF THE MID LEVEL
INVERSION WILL ALLOW SCATTERED THUNDERSTORMS TO FORM OVER THE
FOOTHILLS AND MOUNTAINS. ISOLATED THUNDERSTORMS SHOULD BE ABLE TO
DEVELOP ACROSS THE URBAN CORRIDOR AND NORTHEAST PLAINS. MOISTURE AND
INSTABILITY WILL BE LIMITED...SO THE STORMS ARE EXPECTED TO BE ON
THE WEAK SIDE WITH BRIEF HEAVY RAIN AND WIND GUSTS TO 40 MPH.
CONVECTION WILL COME TO AN END THIS EVENING AS THE AIRMASS
STABILIZES. A SURFACE HIGH OVER THE PLAINS STATES WILL BRING
SOUTHERLY WINDS TODAY WITH GUSTS UP TO 25 MPH TODAY OVER EASTERN
COLORADO.
LONG TERM...THE STRONG UPPER LEVEL SUBTROPICAL HIGH PRESSURE
RIDGE CENTERED OVER THE SOUTHERN GREAT PLAINS WEAKENS SOME AND
SHIFTS WESTWARD ON SATURDAY...THEN BACKS UP OVER TEXAS/OKLAHOMA
AGAIN ON SUNDAY. THIS ALLOWS A MODEST STREAM OF MOIST SUBTROPICAL
AIR TO SURGE NORTHEASTWARD OVER COLORADO ON SUNDAY. 850-500MB
PRECIPITABLE WATER AND MEAN LAYER SPECIFIC HUMIDITY VALUES ON THE
MARGINAL SIDE WHEN IT COME TO HEAVY RAIN PRODUCERS FOR OUR PART OF
THE STATE. BEFORE THIS INFLUX OF MONSOONAL MOISTURE ARRIVES ON
SUNDAY...THERE SHOULD STILL BE ADEQUATE MOISTURE AVAILABLE FOR
ISOLATED SHOWERS IN THE HIGH COUNTRY LATE SATURDAY MORNING AND
SCATTERED T-STORMS IN THE AFTERNOON AND EVENING. ON THE PLAINS
RAIN CHANCES DO NOT LOOK AS PROMISING ALTHOUGH MODELS INDICATE A
LINE OF CONVECTION/QPF ASSOCIATED WITH A BNDRY LAYER SHEAR AXIS/
CONVERGENCE ZONE STRETCHING NORTHEAST FROM SOUTHEAST DOUGLAS
COUNTY DURING THE AFTERNOON AND EARLY EVENING HOURS. THIS COULD
SERVE AS A FOCUS FOR T-STORM DEVELOPMENT DURING THIS PERIOD...BUT
ANY QPF SHOULD REMAIN ON THE LIGHT SIDE...SOMEWHERE IN THE 0.10 TO
0.20 INCH RANGE...ASSUMING STORM UPDRAFTS WILL BE ABLE TO BREAK
THROUGH THE STG MID-LEVEL CAP OVER THE AREA.
ITS SUNDAY WHEN STORM CHANGES SHOULD INCREASE EVERYWHERE WITH
PRECIPITABLE WATER VALUES EAST OF THE MTNS RISING DURING THE
MORNING HOURS WITH EASTERLY UPSLOPE FLOW. BY AFTERNOON UPSLOPE
FLOW APPEARS TO SUBSIDE BUT BY THEN MEAN LAYER PRECIPITABLE WATER
VALUES ARE PROGGED TO BE SOMEWHERE BETWEEN 0.85 AND 1.1 INCH.
THIS LATEST PUSH OF MOIST SUBTROPICAL AIR FROM THE DESERT
SOUTHWEST IS NOT ALL THAT IMPRESSIVE AND THE 850-500MB MEAN LAYER
FLOW MORE WESTERLY THAN SOUTH-SOUTHWESTERLY...CHANCES ARE STORM
MOTIONS WILL BE FASTER AND RAINFALL RATES NOT AS GREAT THIS TIME
AROUND. STILL CAN/T RULE OUT A FEW HEAVY RAIN PRODUCERS MAINLY
OVER THE SOUTHERN FOOTHILLS...PARK COUNTY AND OUT ACROSS THE FAR
NORTHEAST PLAINS LATE IN THE AFTERNOON AND EVENING.
BY MONDAY...THE UPPER RIDGE MAKES A WESTWARD RUN AGAIN ACROSS NEW
MEXICO WHICH PLACES COLORADO UNDER A DRIER...SLIGHTLY WARMER
WESTERLY FLOW. MODELS SHOW PRECIPITABLE WATER VALUES ON THE DOWN
TURN WITH VALUES BY LATE AFTERNOON IN THE 0.65 TO 0.85 INCH RANGE
ON THE PLAINS AND LOWER THAN THAT IN THE HIGH COUNTRY. AIRMASS ON
THE PLAINS...ESPECIALLY NORTH OF INTERSTATE 70 ALSO APPEARS TO BE
QUITE CAPPED WITH WARMING ALOFT WITH THE PASSING RIDGE.
HOWEVER...SHOULD BE ENOUGH MOISTURE AND INSTABILITY AROUND TO
GENERATE SCATTERED LIGHT TO MODERATE T-STORMS IN THE MTNS AND
ISOLATED LATE DAY STORMS ALONG THE PALMER DIVIDE AND OVER THE HIGH
MTN VALLEYS. THE I-25 URBAN CORRIDOR WILL PROBABLY MISS OUT ON ANY
RAIN ON MONDAY.
FOR THE REMAINDER OF THE WEEK...THE UPPER RIDGE IS FORECAST TO
CONTINUE ITS WESTWARD MIGRATION ACCORDING TO THE GFS WITH IT
CENTERED OVER THE 4-CORNERS ON WEDNESDAY AND SLIGHTLY SOUTHWEST OF
THERE ON THURSDAY AND FRIDAY. THE ECMWF DON/T TAKE THE RIDGE AS
FAR WEST BUT IT STILL KEEPS IT OVER NEW MEXICO WHICH ESSENTIALLY
CUTS OFF COLORADO FROM ANY SUBTROPICAL/MONSOONAL MOISTURE FOR
LATER IN THE WEEK. SO EXCEPT FOR THE USUAL ISOLATED AFTERNOON AND
EARLY EVENING GUSTY T-STORMS IN THE HIGH COUNTRY...THE LATTER
HALF OF THE WEEK LOOKS DRY FOR THE PLAINS. TEMPERATURES THROUGHOUT
THE UPCOMING WEEK ARE EXPECTED TO REMAIN ABOVE AVERAGE WITH THE
WARMEST READINGS THIS WEEKEND EVEN WITH THE INCREASE IN STORMS ON
SUNDAY.
AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS.
SCATTERED THUNDERSTORMS WILL FORM OVER THE HIGHER TERRAIN THIS
AFTERNOON. SOME OF THE STORMS WILL SPREAD ONTO THE PLAINS. WIND
GUSTS TO 35 KNOTS AND BRIEF HEAVY RAIN WILL ACCOMPANY THE
THUNDERSTORMS. OUTSIDE OF THE THUNDERSTORMS...SOUTHERLY WINDS
WILL INCREASE THIS AFTERNOON WITH GUSTS UP TO 25 KNOTS.
HYDROLOGY...SCATTERED THUNDERSTORMS WILL DEVELOP OVER THE HIGHER
TERRAIN TODAY. THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING A
BRIEF PERIOD OF HEAVY RAIN. MOISTURE AND INSTABILITY WILL BE
LIMITED SO ANY HEAVY RAIN WILL BE SHORT LIVED. THE THREAT FOR
FLOODING WILL CONTINUE TO BE VERY LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1105 AM EDT FRI JUL 27 2012
.UPDATE...
SHOWER AND ISOLATED THUNDERSTORM ACTIVITY HAS PERSISTED THIS MORNING
IN PARTS OF THE SOUTH. ANY LINGERING BOUNDARIES OR ENHANCED
BAROCLINITY DUE TO SOLAR SHELTERING FROM REMNANT CLOUD COVERAGE MAY
FOCUS SOME EARLIER REDEVELOPMENT THIS AFTERNOON. WHEN CONSIDERING
THE LATEST HI-RES SHORT TERM GUIDANCE... THE HRRR SOLUTION HAS A
BETTER HOLD ON SOME OF THE LINGERING CONVECTION IN THE SOUTH THIS
MORNING AND SUGGESTS SCATTERED REDEVELOPMENT ACROSS MUCH OF CENTRAL
AND NORTHERN GA AS EARLY AS 17Z. LATELY THE HRRR SEEMS TO BE A BIT
BULLISH WITH DEVELOPMENT EARLY ON. IT ALSO DOES NOT HAVE NEARLY AS
MUCH CONVECTION TRIGGER FROM THE IMPINGING UPPER SHORTWAVE TROUGH
FROM THE NORTH LATER...WHICH THE WRF BUYS INTO MORE. STILL THINKING
THE NORTH WILL HAVE BETTER CHANCES LATER DUE TO APPROACH OF UPPER
TROUGH...AND PARTS OF THE SOUTH WILL HAVE DECENT CHANCES AS WELL
WITH ENHANCED MOISTURE FIELD AND AFOREMENTIONED REMNANT MORNING
ACTIVITY. WILL MAINTAIN CHANCE POPS EARLY AREA-WIDE TRENDING TO
LIKELY POPS IN THE NORTH AND SOUTH FROM 21-00Z.
OTHERWISE...BUMPED DOWN TEMPS IN THE SOUTH DUE TO LINGERING
PRECIP/CLOUD COVERAGE AND MADE ADJUSTMENTS TO DEWPOINT TRENDS.
CHANGES STILL KEPT MUCH OF THE SOUTHERN PORTION WITHIN A FEW DEGREES
OF HEAT ADVISORY CRITERIA SO WILL MAINTAIN CURRENT PRODUCT. PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 346 AM EDT FRI JUL 27 2012/
.HEAT ADVISORY FOR SOUTHEAST SECTIONS THIS AFTERNOON...
.SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST SHOWS TROUGH REMAINS IN
PLACE ALONG THE EASTERN SEABOARD INTO THE CAROLINAS WITH SOME WEAK
RIDGING NOTED OVER WESTERN GEORGIA. ENHANCED CLUSTER OF STORMS
WHICH DEVELOPED OVER SOUTHERN SECTIONS LAST EVENING AND SENT
DEVELOPING OUTFLOWS NORTHWARD HAS LONG SINCE ABATED LEAVING BEHIND
MOSTLY CLOUDY CONDITIONS. MOST ALL OF THIS IS IN THE FORM OF HIGH
CLOUDS WITH NO LOW CLOUDS OF NOTE TO THE WEST EVEN THOUGH MODELS
ARE BULLISH ON THE FORMATION LATER TONIGHT INTO FRIDAY MORNING.
WITH YESTERDAYS ACTIVITY...ESPECIALLY LATE STORMS OVER THE
NORTH...ATMOSPHERE IS SLOWLY PROVING IT CAN SUSTAIN CONVECTION
WITH DECAYING RIDGE. TODAY LOOKS TO BE A TRANSITION DAY FOR THE
AREA AS TROUGH BECOMES MORE ENTRENCHED INTO THE TENNESSEE VALLEY
ALLOWING FOR FURTHER BREAKDOWN OF THE RIDGE. BASED ON MOISTURE
DISTRIBUTION...WITH ENHANCED LOW LEVEL MOISTURE FROM COLUMBUS TO
MACON...FEEL THESE AREAS WILL SEE INITIATION FIRST WITH AREAS TO
THE NORTH RECEIVING A LATER START AS SHORTWAVE ENERGY APPROACHES.
CAPE VALUES AREA WIDE LOOK TO BE IN THE 3000 PLUS RANGE THIS
AFTERNOON AND WITH BETTER SYNOPTIC SETUP...HAVE GONE 10 TO 30
PERCENT ABOVE GUIDANCE FOR MOST AREAS.
ALTHOUGH TIMING OF STORMS WILL BE KEY...STILL LOOKING AT SOUTHEAST
SECTIONS POSSIBLE SEEING HEAT INDICES IN EXCESS OF 105 THIS
AFTERNOON AND HEAT ADVISORY WILL BE POSTED.
AS FAR AS SEVERE POTENTIAL TODAY...ISOLATED SEVERE STORMS WILL BE
POSSIBLE AREA WIDE BUT APPEARS BEST CHANCE FOR ORGANIZED SEVERE
WILL BE TO THE NORTH WITH APPROACHING UPPER LEVEL ENERGY.
DOWNDRAFT CAPE NOT ALL THAT IMPRESSIVE TODAY WITH VALUES LESS THAN
500 J/KG FOR THE MOST PART BUT PRECIPITATION LOADING ALONE WILL
STILL LEAD TO ISOLATED STRONG TO SEVERE STORMS. TEMPS ALOFT WILL
NOT BE ESPECIALLY COLD EITHER WITH 500 TEMPS AROUND -6C TO -7C BUT
AGAIN...SOME ISOLATED SEVERE HAIL POSSIBLE AS WAS THE CASE LAST
NIGHT.
FOR SATURDAY...MODELS ALL WANT TO PUSH FRONTAL BOUNDARY INTO
SOUTHERN SECTIONS OF THE FORECAST AREA AND KEEP NORTHERN SECTIONS
DRY. STRONG SHORTWAVE ARRIVES LATE IN THE DAY HOWEVER FOR THE
NORTH AND FEEL ENOUGH MOISTURE WILL BE PRESENT ALONG WITH
CONTINUED HIGH INSTABILITY TO WARRANT LOW END CHANCE POPS FROM
ATLANTA NORTHWARD. CONTINUED STEAMY TO THE SOUTH IN VICINITY OF
THE FRONT AND DEPENDING ON HOW TODAY FARES...MAY NEED ANOTHER HEAT
ADVISORY FOR SATURDAY AS WELL.
DEESE
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT OVER THE CENTRAL GA AREA EARLY SUNDAY WILL LIKELY
BECOME STATIONARY...DISSIPATING INTO TUESDAY. DURING THIS TIME AN
UPPER TROUGH SETS UP OVER THE EASTERN STATES WITH NW FLOW
AFFECTING THE AREA AND THE POTENTIAL FOR SHORT WAVES IN THAT FLOW
TO BRING SOME AMOUNT OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THIS PATTERN LOOKS TO CONTINUE THROUGH THE REST OF THE LONG TERM
WITH INDICATIONS OF ANOTHER FRONT MOVING TO THE AREA ON THURSDAY.
AS THE UPPER TROUGH BECOMES BETTER ESTABLISHED AND DEEPENS OVER THE
AREA DURING MID WEEK OR SO...THIS SHOULD COOL HIGH TEMPERATURES
CLOSER TO NORMAL.
BDL
&&
.AVIATION...
12Z UPDATE...
EARLY START TO TSRA FOR SOUTHERN SECTIONS THIS MORNING BUT THUS
FAR HAS REMAINED NORTH OF MCN AND CSG. LOOKING FOR ENHANCED LOW
LEVEL MOISTURE TO PUSH IN FROM THE SOUTH AND WEST THIS MORNING BUT
MUCH UNCERTAINTY HOW SOON AND FAR EAST AND NORTH THIS WILL
PROGRESS. WILL HAVE SLIGHTLY EARLIER START FOR THE SOUTHERN TAF
SITES BUT THINKING A MAJORITY OF THE ACTIVITY WILL BE LATE AND
ASSOCIATED WITH AN UPPER LEVEL SYSTEM MOVING OUT OF TENNESSEE.
HAVE GONE WITH PROB30 AFT 22Z BUT THIS ORGANIZED LINE OF STORMS
COULD ACTUALLY MATERIALIZE A FEW HOURS AFTER THIS ADVERTISED TIME
GIVEN UNCERTAINTY.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON TSRA CHANCES AND TIMING.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 94 73 94 72 / 40 30 30 20
ATLANTA 93 74 92 74 / 50 30 30 10
BLAIRSVILLE 90 66 88 67 / 60 40 30 10
CARTERSVILLE 92 72 93 68 / 60 40 30 10
COLUMBUS 95 75 94 76 / 60 30 30 20
GAINESVILLE 92 73 91 72 / 50 30 30 20
MACON 94 74 95 73 / 60 30 30 20
ROME 93 71 95 68 / 60 30 30 10
PEACHTREE CITY 93 71 92 70 / 50 30 30 20
VIDALIA 94 76 94 75 / 40 30 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BLECKLEY...CRISP...DODGE...DOOLY...EMANUEL...HOUSTON...
JEFFERSON...JOHNSON...LAURENS...MONTGOMERY...PULASKI...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.
&&
$$
SHORT TERM...DEESE/BAKER
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
546 AM CDT FRI JUL 27 2012
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
THE RAP AND NAM SHOW MID LEVEL DRY AIR ADVECTING FROM THE NORTH
INTO NORTHEAST KS WITH THE SFC RIDGE. THEREFORE THINK THE
ISOLATED CONVECTION AROUND HIAWATHA WILL BE SHORT LIVED. LATEST
11U-1.9U SATELLITE IMAGES SHOWS ACCUS IS BECOMING LESS
PREDOMINATE ACROSS SOUTHERN NEB AS WELL. THEREFORE WITH RISING MID
LEVEL HEIGHTS ANTICIPATE THROUGH 12Z SAT...VFR CONDITIONS ARE
EXPECTED TO PERSIST.
WOLTERS
&&
.PREV DISCUSSION... /ISSUED 311 AM CDT FRI JUL 27 2012/
TODAY/TONIGHT...A WEAK FRONTAL BOUNDARY ASSOCIATED WITH A STRONG
SHORTWAVE TROUGH OVER THE WESTERN GREAT LAKES IS HELPING TO
GENERATE SHALLOW ISOLATED CONVECTION OVER N MO AND NE KS. MODELS
SUGGEST THIS ACTIVITY WILL BE SHORT LIVED AND SHOULD GRADUALLY
DISSIPATE SHORTLY AFTER SUNRISE AS THE ASCENT FROM THE UPPER
DISTURBANCE IS DISPLACED FURTHER TO THE EAST. OTHERWISE SFC HIGH
PRESSURE BUILDS INTO THE MO RIVER VALLEY TODAY INTO TONIGHT. SFC
WIND TRAJECTORIES WILL BE FROM THE NORTH UPON THE BOUNDARY PASSAGE
AND AS THE HIGH BRIEFLY SETTLES IN. TEMPERATURES THIS AFTERNOON
WILL BE SIMILAR TO YESTERDAYS READINGS...WITH THE WARMEST
CONDITIONS ALONG AND SOUTH OF THE INTERSTATE 70 CORRIDOR.
OVERNIGHT LOWS WILL COOL INTO THE UPPER 60S TO LOWER 70S...WHICH
WILL BE THE COOLEST READINGS REMAINING IN THE NEXT 7 DAYS.
SATURDAY/SUNDAY...THE SFC HIGH MOVES OFF THE EAST WITH SOUTHERLY
WINDS RETURNING. HOT TEMPERATURES ARE EXPECTED TO ALSO RETURN OVER
THE WEEKEND AS UPPER RIDGING BUILDS INTO THE CENTRAL PLAINS. THE H85
THERMAL AXIS TENDS TO SET NEAR OR OVER THE CWA DURING THIS
PERIOD...TRANSLATING TO READINGS REACHING THE 99-107 RANGE. NO
PLANS ATTM FOR HEAT HEADLINES...BUT CERTAINLY THIS IS SOMETHING THAT
WILL NEED TO BE CLOSELY MONITORED IN SUBSEQUENT FORECASTS. SUNDAY
COULD POTENTIALLY BE EVEN WARMER THAN CURRENTLY ADVERTISED AS
WESTERLY H85 DOWNSLOPE COMPONENT SETS UP OVER KANSAS. LIKEWISE...HAVE
ALSO INSERTED SLIGHT CHANCE OF PRECIPITATION ON SUNDAY AFTERNOON AS
CONVECTIVE TEMPERATURE SHOULD EASILY BE EXCEEDED. ANY CONVECTION
WOULD LIKELY BE ISO/SCT IN NATURE...SHORT-LIVED...AND CLOSELY TIED
TO THE SFC THERMAL AXIS DURING THE 20-01Z TIME FRAME. POINT
SOUNDINGS WOULD SUGGEST ANOTHER POTENTIAL MICROBURST CONCERN WITH
IMPRESSIVE INVERTED-V PROFILE...IF CONVECTION INDEED DEVELOPS DURING
THE AFTERNOON.
MONDAY AND BEYOND...MINUS ANY WEAK PERTURBATIONS PASSING THROUGH
NEBRASKA ON THE SOUTHERN PERIPHERY OF THE UPPER JET THAT MAY YIELD
VERY MARGINAL PRECIPITATION CHANCES...THE UPPER RIDGE APPEARS TO
REMAIN FIRMLY IN PLACE OVER KANSAS THROUGH THE EXTENDED
FORECAST...RESULTING IN HOT AND DRY WEATHER CONTINUING. HIGH
TEMPERATURES IN THE UPPER 90S TO LOWER 100S SEEM QUITE REASONABLE.
BLAIR
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1102 AM EDT FRI JUL 27 2012
.SYNOPSIS...
A SLOW MOVING UPPER LEVEL SYSTEM WILL CONTINUE THE RISK FOR
SHOWERS AND STORMS THROUGH SATURDAY. DRIER AND MORE COMFORTABLE
CONDITIONS WILL SETTLE IN BY THE END OF THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE DELAYED ONSET OF PRECIPITATION SLIGHTLY WITH 11AM UPDATE.
TIMING ALIGNS A BIT BETTER WITH 10Z HRRR AND 12Z NAM RUNS. SEVERE
POTENTIAL WILL BE AT LEAST PARTLY CONTINGENT ON WHAT HAPPENS WITH
CLOUD COVER DURING THE AFTERNOON. WITH MOSTLY CLOUDY SKIES
PERSISTING INTO THE LATE MORNING...THIS SHOULD REDUCE OVERALL
HEATING FOR THE DAY. HOWEVER...THIS CERTAINLY DOES NOT RULE OUT
POTENTIAL FOR SEVERE WEATHER...ESPECIALLY IN SPC SLIGHT RISK AREA
WHICH INCLUDES OHIO AND NORTHERN WV PANHANDLE COUNTIES. NO RELIEF
FOR MUGGY AIR...WITH DEWPOINTS REMAINING IN THE 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
RECENT SREF MODEL OUTPUT, WITH DETAILS FROM NAM MODEL OUTPUT,
SHOWS HUMID AND HENCE UNSTABLE CONDITIONS REMAINING ACROSS THE
UPPER OHIO VALLEY UNTIL THE COLD FRONT, WITH LOWER DEW POINTS,
MOVES SOUTHWARD THROUGH AREA, SATURDAY NIGHT. THUS HAVE MAINTAINED
A CHANCE OF THUNDERSTORMS INTO SATURDAY EVENING.
HIGH PRESSURE SHOULD PROVIDE DRY CONDITIONS SUNDAY.
FORECASTED TEMPERATURES USING BLEND OF RECENT GFS AND NAM MOS AND
SREF MEAN VALUES, WHICH INDICATED TEMPERATURES CONTINUING WARMER
THAN NORMAL, WITH DAYTIME HIGHS BY UP TO 5 DEGREES, AND EARLY
MORNING LOWS BY UP TO 10 DEGREES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXPECT DRY CONDITIONS TO HOLD UNDER WEAK SURFACE HIGH PRESSURE
THROUGH MONDAY.
AN UPPER TROUGH IS PROGGED TO REMAIN OVER THE EAST COAST THROUGH
MUCH OF NEXT WEEK. MODELS CONTINUE TO HINT AT A SURFACE LOW MOVING
SLOWLY ALONG THE EAST COAST TUESDAY THROUGH THURSDAY...WHILE A
FRONTAL BOUNDARY APPROACHES FROM THE GREAT LAKES. PLAN TO KEEP
CHANCE POPS FOR SHOWERS AND THUNDERSTORMS TUESDAY INTO THURSDAY.
FORECAST TEMPERATURES ARE CLOSE TO HPC GUIDANCE AND WILL BE
GENERALLY A FEW DEGREES ABOVE NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
ISOLATED LOCATIONS REMAIN UNDER IFR CIGS LATE THIS MORNING...BUT
IMPROVEMENT TO VFR IS ANTICIPATED DURING THE AFTERNOON. SCT TO
NMRS SHRA/TSRA AND ASSOCIATED RESTRICTIONS ARE EXPECTED AS LOW
PRES MOVES ALONG FRONT THIS AFTN AND EVE. EXPECT GENL MVFR IN
SHRA AND IFR VSBY IN THE TSRA.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SCT TSRA/RESTRICTION POTENTIAL WL RMN THROUGH SATURDAY AS AN UPR
TROF AND A SECONDARY FRONT PUSH ACRS THE UPR OH VALLEY. DRY VFR
CONDITIONS ARE EXPECTED UNDER SFC HIGH PRES SUNDAY AND MONDAY.
INCRSG MOISTURE ASSOCIATED WITH AN EAST COAST LOW MAY FUEL SCT
SHRAS AND TSRA BY TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1055 AM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TODAY AND SLOWLY MOVE THROUGH
THE REGION TONIGHT. HIGH PRESSURE RETURNS SATURDAY AND REMAINS
INTO THE BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT CURRENTLY DRAPED FROM THE ERN GREAT LAKES ACROSS THE
PA/NY BORDER WILL SAG SOUTHEAST TOWARD THE CENTRAL MID ATLANTIC
TODAY. 12Z MODIFIED SOUNDING STILL SUPPORTS HIGH TEMPS IN THE MID
90S AT IAD...SO HIGH TEMP FORECAST FOR UPPER 90S IN DC/BALTIMORE
AREA STILL LOOKS VALID. TEMPS RUNNING A FEW DEGREES COOLER WEST OF
THE METRO AREAS DUE TO DEBRIS CLOUDS...BUT CLEARING TREND IS IN
PLACE LATE THIS MORNING.
SCATTERED SHOWERS HAVE DEVELOPED ALONG A PRE-FRONTAL TROUGH OVER
CENTRAL WV. 12Z NAM/09Z SREF SUPPORT THIS ACTIVITY BUILDING AND
MOVING EWD TOWARDS THE CWA THIS AFTN...BUT CLOUDS IN PLACE OVER WV
MAY LIMIT COVERAGE AND SEVERE THREAT. HRRR DOES NOT SUPPORT THIS
DEVELOPMENT...BUT INSTEAD FOCUSES CONVECTIVE INITIATION OVER THE
MOUNTAINS AND PIEDMONT EARLY THIS AFTERNOON. 12Z IAD SOUNDING
INDICATES SUFFICIENT SHEAR OVER THE REGION...AND IF SURFACE TEMPS
WARM AS FORECAST A 750MB CAP SHOULD BE BROKEN ALLOWING SB CAPE TO
REACH 2600 J/KG. SPC HAS A SLIGHT RISK OVER MOST OF VA AND MD EAST
OF THE BLUE RIDGE TODAY. MAIN THREAT WOULD BE DAMAGING
WINDS...ALTHOUGH A LARGE HAIL THREAT EXISTS AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
COLD FRONT SLOWLY SAG SOUTH TOWARD SERN VA WITH UPR TROUGH
REMAINING BACK OVER THE OH VLY. SHOULD SEE A BREAK IN PRECIP FOR
I-95 AND WEST /NOTE THE WEST/ BY THE EVENING...WITH PRECIP
PERSISTING EAST/SOUTH OF I-95 WELL INTO THE OVERNIGHT. MIN TEMPS MID
60S PIEDMONT AND WEST...LOW TO MID 70S I-95 AND EAST.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE ULTRA HIGH TEMPS WL BE HELD AT BAY DURG THE XTND PD. THIS IS
FREQUENTLY THE TIME OF YR WHEN THE "FOUR CORNERS HIGH" DVLPS OVR THE
SWRN U.S. ...AND THIS APPEARS TO BE THE CASE IN ALL OF THE XTND
MDLS. BECAUSE OF THIS THE ERN U.S. WL BE UNDER A SLT UPPER TROF.
THIS WL KEEP THE REALLY HOT WX...AND THE 70+ DWPTS...AT BAY FOR
THE FINAL DAYS OF JUL AND THE BEGINNING OF AUG. IN THE MID
ATLC...XPCT MOST OF THE XTND PD TO HV HIGH TEMPS IN THE MU80S.
LOWS RANGING FM THE L70S IN THE CITIES TO THE U50S IN THE
HIGHLANDS...BUT THE MAJORITY OF WL HV LOWS IN THE M60S.
THERE ISN`T MUCH TO HANG ONTO REGARDING POP CHCS. W/ ERN TROF IT
IS PSBL THAT A BNDRY COULD DVLP SOMETIME NEXT WK AND SERVE AS A
FOCUS FOR TSTM DVLPMNT...OTHERWISE SCT AFTN TSTMS IS THE BEST CHC
FOR RAFL.
ONE DAY CLOSER TO THE END OF THE MONTH...THIS RMNS THE WARMEST JUL
(AVG TEMP) IN DC ON RECORD. IT`S AMAZING THAT #2 AND 3 ARE THE PRVS
TWO YRS...EVEN THO RECORDS GO BACK TO 1871. BWI - THIS JUL IS IN
THE #2 SLOT...0.2 DEGS BEHIND 2010. THIS JUL IS ALSO #1 FOR
IAD...0.5 DEG AHD OF LAST YR.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR THIS MORNING. BRIEF LIGHT RAIN EXPECTED AT KMRB BEFORE 13Z.
THUNDERSTORMS/POTENTIAL PERIODS OF IFR CONDS THIS AFTERNOON AHEAD
OF A COLD FRONT. SWLY/WLY FLOW AROUND 10 KT TODAY. COLD FRONT
SLOWLY CROSSES TONIGHT WITH VFR CONDITIONS UNDER MID LEVEL CLOUDS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS SUNDAY BEFORE MOVING OFF
THE COAST FOR THE FIRST PART OF NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL INCREASE THE CHANCES FOR SHOWERS/TSTMS DURING THIS
TIME...HOWEVER NO WIDESPREAD SVR OUTBRK CAN BE SEEN ON THE
HORIZON.
&&
.MARINE...
WLY/SWLY FLOW AROUND 10 KT CONTINUE THROUGH TODAY. SCATTERED
THUNDERSTORMS EXPECTED LATE THIS AFTERNOON WELL INTO THE OVERNIGHT
WITH A DAMAGING WIND THREAT AHEAD/ALONG A SLOW MOVING COLD FRONT.
SURFACE HIGH PRESSURE WILL BUILD OVER THE WATERS SUNDAY BEFORE
MOVING OFF THE COAST EARLY NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL IBRING ABT THE PSBLTY OF SCT SHOWERS/TSTMS NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR DCZ001.
MD...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MDZ006-007-011-
013-014-016>018.
VA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR VAZ052>057.
WV...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE...KCS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1041 AM EDT FRI JUL 27 2012
.UPDATE...
THE REGIONAL WATER VAPOR LOOP SHOWS A FAIRLY HEALTHY MID LEVEL
WAVE OVER ERN WISCONSIN. ALTHOUGH THIS WAVE IS EXPECTED TO DAMPEN
AS IT TRACKS ACROSS LOWER MI LATER TODAY...THERE WILL STILL BE
ADEQUATE FORCING FOR LARGE SCALE ASCENT DURING PEAK DAYTIME
HEATING. RECENT TRENDS IN THE VISIBLE LOOP ARE SHOWING SOME OF THE
LOW STRATUS STARTING TO TRANSITION TO A BROKEN CU FIELD AS DAYTIME
INSOLATION IS NOW WARMING THE BOUNDARY LAYER. THIS WILL SUPPORT
INCREASING CONVECTIVE CLOUD DEPTHS WHICH WILL LEAD TO OCCASIONAL
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. REGIONAL RADAR IMAGERY
IS SHOWING AN AREA OF MORE PERSISTENT RAIN AND EMBEDDED
THUNDERSTORMS EXTENDING FROM CNTL LOWER MI TO NW LOWER MI...WITHIN
A REGION OF WEAK MID LEVEL DEFORMATION...WHICH WILL TARGET THE
SAGINAW VALLEY AND THUMB THIS AFTERNOON AND EVENING. DEEP LAYER
MOISTURE WILL ALSO BE BETTER TO THE NORTH. GIVEN THE SLOW MOVEMENT
OF THE UPPER WAVE...SOME PROLONGED PERIODS OF MODERATE TO HEAVY
RAINFALL LOOK POSSIBLE ACROSS THE NORTHERN PORTIONS OF THE
FORECAST AREA.
DRY AIR IN THE MID LEVELS FARTHER SOUTH SUGGEST SOME AFTERNOON
STORMS MAY SUPPORT SOME SMALL HAIL. THERE HAS BEEN MORE PERSISTENT
SUNSHINE ACROSS LENAWEE AND MONROE COUNTIES THIS MORNING...WHICH
MAY ALLOW SOME BETTER INSTABILITY TO DEVELOP BY AFTERNOON /SB CAPE
UP TO 2000 J/KG/. THIS REGION WILL ALSO LIE ALONG THE NORTHERN
EDGE OF A 40KT MID LEVEL JET...SUPPORTIVE OF A SLIGHT CHANCE OF
STRONG TO POSSIBLE SEVERE STORMS LATER TODAY.
THE UPDATE WILL BE ISSUED MAINLY TO NUDGE POPS UPWARD.
&&
.AVIATION...ISSUED 647 AM EDT FRI JUL 27 2012
//DISCUSSION...
NE FLOW OFF LAKE HURON HAS HELPED KEEP SURFACE MOISTURE ELEVATED
THUS HAS PRODUCED WIDESPREAD STRATUS. BETWEEN THE LOW STRATUS AND
LINGERING PATCHY FOG...MVFR CONDITIONS COULD CONTINUE FOR A COUPLE
MORE HOURS BEFORE LIFTING BACK TO VFR FOR THE AFTERNOON. THE STRATUS
HAS DONE A GOOD JOB KEEPING MOST OF THE FOG CONTAINED OVER SW LOWER
MI WITH HINTS OF IT APPROACHING FNT AND PTK AT TIMES. SURFACE LOW
PRESSURE SYSTEM APPROACHING LAKE MICHIGAN WILL REACH SE MI THIS
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS HAVE ALREADY STARTED
POPPING UP THIS MORNING BUT COVERAGE WILL INCREASE INTO THE
AFTERNOON AS DIURNAL HEATING AIDES IN THE DEVELOPMENT OF
PRECIPITATION. THIS MORNINGS COVERAGE WILL BE TOO ISOLATED TO
INCLUDE IN THE TAFS AT THIS TIME. HAVE CONTINUED THE MENTION OF
SHOWERS AFTER 18Z SINCE COVERAGE SHOULD BE MORE WIDESPREAD DURING
THAT TIME. WILL HOLD OFF ON MENTIONING THUNDER UNTIL WE CAN GET
BETTER TIMING OF THE STRONGER STORMS.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET AT LEAST
INTERMITTENTLY ON FRIDAY...BUT LOW CONFIDENCE ON TIMING.
* MEDIUM CONFIDENCE IN THUNDERSTORM DEVELOPMENT ON FRIDAY...BUT LOW
CONFIDENCE IN TIMING AND LOCATION.
&&
.PREV DISCUSSION...ISSUED 339 AM EDT FRI JUL 27 2012
SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SC
AVIATION.....DG
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1016 AM EDT FRI JUL 27 2012
.SYNOPSIS...
ISSUED AT 409 AM EDT FRI JUL 27 2012
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY...
BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
WILL THEN PROVIDE PLEASANT WEATHER FOR THE WEEKEND...BUT MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN EARLY NEXT WORK
WEEK. NEAR SEASONAL TEMPERATURES ARE EXPECTED FOR THE NEXT SEVERAL
DAYS.
&&
.UPDATE...
ISSUED AT 1016 AM EDT FRI JUL 27 2012
GIST OF THE GOING FORECAST IS INTACT AS WE HEAD INTO THE
AFTERNOON...WITH ONLY MINOR TWEAKS MADE...PRIMARILY TO NORTHWARD
EXTENT OF EXPECTED PRECIP SHIELD. MODESTLY STRONG UPPER WAVE
CONTINUES TO PROGRESS THROUGH WISCONSIN...WITH A NOTABLE 700-500MB
AXIS OF DEFORMATION FORCING ACTING TO ELONGATE A BAND OF RAIN OVER
MUCH OF THE AREA SOUTH OF M-72. PRONOUNCED LOW LEVEL THETA-E AXIS
RUNNING ACROSS THIS AREA IS ALSO SERVING TO PROMOTE SOME WEAK
INSTABILITY BENEATH COOLING MID LEVELS...WITH UP TO 500 J/KG
MUCAPE PER SHORT TERM RAP FORECAST RAOBS. AS SUCH...NO SURPRISE WE
ARE SEEING OCCASIONAL THUNDER BREAK OUT AS WELL.
HEADING INTO THE LATE MORNING/AFTERNOON...SUSPECT PERIODS OF
SHOWERS AND STORMS WILL CROSS MUCH OF THE SOUTHERN HALF OF THE
CWA...ALL WHILE EXPANSIVE LOW LEVEL RIDGING AND ASSOCIATED DRYING
PUT A DEFINITELY NORTHERN EDGE TO THE PRECIP SHIELD. PER SHORT
TERM GUIDANCE AND STRONG SREF HINTS...WILL TRIM THE NORTHERN TIER
OF HIGHER POPS...WITH AREAS CLOSER TO LAKE HURON (NORTH OF M-32)
AND JUST ABOUT ALL OF EASTERN UPPER PROBABLY OUT OF THE MIX FOR
MUCH OF THE DAY. IN ADDITION TO EXPECTED AXIS OF DEFORMATION
FORCING...WILL LIKELY ALSO SEE SOME DIURNAL HELP TO THE PRECIP
WITHIN A QUITE MOIST AIRMASS...WITH SURFACE TEMPS INTO THE
LOWER/MIDDLE 70S PROMOTING MUCAPE VALUES UP TOWARD 700 J/KG. GIVEN
THE UPPER COLD POOL SKIRTING OVERHEAD AND A GOOD CHUNK OF
AVAILABLE INSTABILITY SITUATED ABOVE THE -12C ISOTHERM...SMALL
HAIL REMAINS A THREAT WITH ANY CONVECTION THAT DEVELOPS.
IN ADDITION...LOCALLY VERY HEAVY RAIN THREAT EXISTS WITHIN A
CORRIDOR OF 1.5+ INCH PWATS DOWN NEAR THE M-55 CORRIDOR WHERE
STEERING FLOW IS AN ANEMIC 5-10 KNOTS. MEANWHILE...FREEZING LEVELS
UP AROUND 10KFT AND A SATURATED ENVIRONMENT BELOW WILL SUPPORT VERY
EFFICIENT WARM RAIN PROCESSES...AND ENTIRELY POSSIBLE A FEW SPOTS
COULD PICK UP A LOCALIZED 2+ INCHES OF RAIN. CERTAINLY SOMETHING TO
WATCH. WILL ALSO HAVE TO WATCH VERY SMALL POTENTIAL FOR WATERSPOUTS
OVER LAKE MICHIGAN WITH UPPER COLD POOL SLIPPING OVERHEAD WHILE
WATER TEMPS ARE IN THE 22-24C RANGE. BEST THREAT WILL PROBABLY BE
OVER THE SOUTHERN HALF OF THE LAKE WHERE LOW LEVEL CONVERGENCE
BOUNDARY WILL RESIDE.
PER SATELLITE TRENDS...HAVE LOWERED GOING HIGHS A COUPLE OF
DEGREES INLAND WITH ONGOING UPSLOPE FLOW INTO THE HIGHER TERRAIN
LIKELY CAPPING THINGS AROUND 70 DEGREES...WITH DOWNSLOPE FLOW INTO
NORTHWEST LOWER KICKING THINGS TOWARD THE MID 70S. WARMEST SPOTS
WILL BE EASTERN UPPER WITH THINNING CLOUDS INTO THE AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 409 AM EDT FRI JUL 27 2012
EARLY MORNING SURFACE ANALYSIS SHOWS AN EAST-WEST ORIENTED TROUGH
AXIS LYING ACROSS SOUTHERN LOWER MICHIGAN/CENTRAL WISCONSIN.
COMPACT UPPER LOW WAS SPINNING SOUTHEAST INTO NORTHWEST
WISCONSIN...WITH A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ARCING
AROUND THIS CIRCULATION FROM THE MICHIGAN/WISCONSIN BORDER SOUTHWARD
ACROSS EASTERN WISCONSIN (WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD AHEAD OF THIS LOW SPREADING ACROSS LAKE MICHIGAN).
MEANWHILE...A FEW SPOTTY RADAR RETURNS DEVELOPED NORTH OF THE
SURFACE TROUGH AXIS SOUTH OF THE M-55 CORRIDOR WHERE LOW LEVEL LAPSE
RATES WERE LIKELY A LITTLE STEEPER PER 00Z DTX SOUNDING.
UPPER LEVEL FEATURE WILL CONTINUE TO TRACK SOUTHEAST AND CROSS
SOUTHERN LOWER MICHIGAN DURING THE DAY. WEAK RIDGE OF HIGH PRESSURE
WILL BUILD INTO NORTHERN MICHIGAN IN THE WAKE OF THIS SYSTEM TONIGHT.
TRACK OF THE UPPER LEVEL LOW SUGGESTS HIGHEST PRECIPITATION CHANCES
TODAY WILL BE ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
WILL BENEFIT THE MOST FROM THE SYNOPTIC COMPONENT WHICH SHOULD
ARRIVE THIS MORNING...PLUS STRONGEST DIURNAL COMPONENT WHERE LOW
LEVEL MOISTURE WILL BE MAXIMIZED AND MAY RESULT IN MLCAPE VALUES IN
THE 1000J/KG RANGE. PRECIPITATION CHANCES WILL BECOME MORE
SCATTERED TO THE NORTH WITH DRIER LOW LAYERS...AND LOOKING LIKE MOST
OF EASTERN UPPER WILL PROBABLY ESCAPE WITH LITTLE SIGNIFICANT
PRECIPITATION. THERMAL THROUGH ASSOCIATED WITH UPPER LEVEL WAVE
WILL LOWER FREEZING LEVELS...THUS STORMS WILL BE CAPABLE OF
PRODUCING HAIL. PLAN TO CARRY AN EXPLICIT MENTION OF SMALL HAIL
SOUTH OF A CVX-OSC LINE FROM LATE MORNING ONWARD. WARMEST HIGHS
TODAY WILL PROBABLY BE NORTH OF THE BRIDGE WHERE THERE WILL BE MORE
SUN ESPECIALLY LATER TODAY...IN GENERAL EXPECT HIGHS MAINLY IN THE
70S.
AS UPPER WAVE SLIPS INTO THE OHIO VALLEY THIS EVENING AND DRIER AIR
FILTERS INTO NORTHERN MICHIGAN IN ITS WAKE...THREAT FOR SHOWERS WILL
COME TO AN END ACROSS CENTRAL LOWER COUNTIES WITH SKIES CLEARING.
MAYBE A LITTLE PATCHY FOG ACROSS PARTS OF NORTHERN LOWER...BUT
SHOULD BE A SEASONABLY CHILLY NIGHT. COULD SEE A FEW SHELTERED
SPOTS DROPPING BELOW 50 EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM EDT FRI JUL 27 2012
CURRENT UPPER LEVEL PATTERN SET TO CHANGE LITTLE FOR THE FORESEEABLE
FUTURE...FEATURING INTERMOUNTAIN WEST/HIGH PLAINS RIDGING BOOKENDED BY
EASTERN NOAM AND FAR EAST PACIFIC TROUGHINESS. AS A RESULT...
RECENTLY ESTABLISHED NORTHWEST FLAVOR TO MID LEVEL FLOW OVER THE
LAKES WILL REMAIN REMARKABLY PERSISTENT...KEEPING TEMPERATURES
LOCKED IN TO NEAR NORMAL LEVELS AND ALLOWING PERIODIC RAIN CHANCES
AS OCCASIONAL DISTURBANCES ROTATE THROUGH THE REGION. FORECAST
CONCERNS RELEGATED TO THE LATTER OF THESE TWO...FOCUSING ON SHOWER
AND STORM CHANCES NEXT WORK WEEK.
RESERVOIR OF DRY CANADIAN AIR SWEEPS SOUTH INTO THE NORTHERN LAKES
BEHIND TOMORROWS DEPARTING SYSTEM...SETTING UP A MAINLY QUIET...DRY
WEEKEND. OVERHEAD HIGH PRESSURE EXPECTED TO LEAD TO EXCELLENT LAKE
BREEZE DEVELOPMENT SATURDAY...AND COMBINED WITH LINGERING 850MB
THERMAL TROUGH...SHOULD SET UP A PRETTY DECENT INLAND CU FIELD BY
AFTERNOON. FORMIDABLE MID LEVEL CAP EXPECTED TO KEEP CLOUD HEIGHTS
IN CHECK AND PREVENT ANY SHOWER DEVELOPMENT. LATEST PROGS STARTING
TO THROW SOME CONCERN INTO INHERITED DRY SUNDAY... ESPECIALLY ACROSS
EASTERN UPPER. SUBTLE MID LEVEL WAVE AND BEGINNINGS OF MODEST RETURN
FLOW NOW SUPPORTING SOME EASTERN UPPER SHOWERS BY AFTERNOON.
GUIDANCE IS NOTORIOUS FOR BRINGING IN MOISTURE TOO QUICKLY...
ESPECIALLY WITH AN ANTECEDENT RELATIVELY DRY AIR MASS. WILL REFRAIN
FROM INTRODUCING ANOTHER PERIOD OF LOW END SHOWER POTENTIAL (SEE
BELOW)...WAITING FOR MORE CONSISTENCY BEFORE DOING SO. NEAR SEASONAL
HIGH TEMPERATURES EXPECTED BOTH AFTERNOONS...WITH READINGS IN THE
UPPER 70S AND LOWER 80S.
"POTENTIALLY" SOMEWHAT MORE ACTIVE PERIOD OF WEATHER RETURNS NEXT
WORK WEEK...WITH ABOVE OUTLINED FLOW AT LEAST OPENING UP THE
OPPORTUNITY FOR A FEW DISTURBANCES TO ROTATE THROUGH THE REGION.
NOTHING EARTH SHATTERING PER TRENDS...WITH GUIDANCE SUGGESTING LOW
AMPLITUDE WAVES AND DEEPEST CORE OF MOISTURE TO REMAIN WELL TO OUR
SOUTHWEST. AS EXPECTED WITH THIS FLOW REGIME...EXACT TIMING REMAINS
PROBLEMATIC AT BEST...WITH THE ECMWF LAGGING BEHIND BOTH THE GFS AND
GEM BY SEVERAL HOURS WITH LEAD WAVE LATE SUNDAY NIGHT INTO MONDAY.
SIMPLY NOT PRUDENT AT THIS HOUR TO PICK ONE OVER THE OTHER...AND
WILL RIDE WITH LATE SUNDAY NIGHT INTO MONDAY LOW END RAIN CHANCES.
SAME GOES FOR MONDAY NIGHT AND TUESDAY AS ADDITIONAL SUPPORT
PINWHEELS OVER THE REGION. UNFORTUNATELY...BECAUSE OF SAID TIMING
CONCERNS...SIMPLY NO WAY TO SIDESTEP INHERITED MULTI-PERIOD RAIN
CHANCES...ALTHOUGH IN ALL LIKELIHOOD...MUCH OF THE TIME OUTLINED
ABOVE WILL REMAIN DRY. OF COURSE...TEMPERATURES DIRECTLY TIED TO
CONVECTIVE TRENDS...BUT OFF THE DECK THERMAL TRENDS SUGGEST HIGHS
BOTH MONDAY AND TUESDAY REMAINING IN THE UPPER 70S AND LOWER 80S.
PATTERN LOOKS TO SIMPLY REPEAT ITSELF LATER IN THE WEEK...WITH
TRENDS SUPPORTING A DRY MID WEEK PERIOD FOLLOWED BY ADDITIONAL RAIN
CHANCES THURSDAY INTO FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 132 AM EDT FRI JUL 27 2012
COMPLEX AND CHALLENGING CLOUD FORECAST THROUGH FIRST HALF OF TAF
PERIOD. AREAS OF MVFR FOG/LOWER CLOUDS OVERNIGHT...WITH INCREASING
CHANCES OF SHOWERS TOWARD 12Z AS UPPER LOW OVER WESTERN SUPERIOR
APPROACHES THE AREA. LOCALIZED IFR VSBY/S POSSIBLE DUE TO FOG
BEFORE THE SHOWERS ARRIVE. CIGS GENERALLY MVFR FOR THE FIRST HALF
OF FRIDAY WITH SCATTERED SHOWERS AND A FEW THUNDERSTORMS. CIGS
STEADILY IMPROVING BY LATER FRIDAY AFTERNOON AS UPPER LOW DEPARTS
AND DRIER AIR BEGINS TO MOVE IN FROM THE NORTHWEST.
WINDS LESS THAN 10 KNOTS THROUGHOUT THE NEXT 24 HOURS.
&&
.MARINE...
ISSUED AT 409 AM EDT FRI JUL 27 2012
EAST/NORTHEAST WINDS EXPECTED TODAY ACROSS THE UPPER LAKES...WITH
THE FORECAST AREA SANDWICHED BETWEEN A TROUGH OF LOW PRESSURE
DROPPING SOUTH TOWARD THE OHIO VALLEY AND A WEAK RIDGE OF HIGH
PRESSURE BUILDING IN FROM THE NORTH. WINDS WILL BACK MORE TOWARD
THE NORTH TONIGHT BUT GRADIENT WILL BE WEAKENING AS AFOREMENTIONED
RIDGE BUILDS IN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...JK
MARINE...JPB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1007 AM EDT FRI JUL 27 2012
.SYNOPSIS...
ISSUED AT 409 AM EDT FRI JUL 27 2012
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY...
BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
WILL THEN PROVIDE PLEASANT WEATHER FOR THE WEEKEND...BUT MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN EARLY NEXT WORK
WEEK. NEAR SEASONAL TEMPERATURES ARE EXPECTED FOR THE NEXT SEVERAL
DAYS.
&&
.UPDATE...
ISSUED AT 1007 AM EDT FRI JUL 27 2012
GIST OF THE GOING FORECAST IS INTACT AS WE HEAD INTO THE
AFTERNOON...WITH ONLY MINOR TWEAKS MADE...PRIMARILY TO NORTHWARD
EXTENT OF EXPECTED PRECIP SHIELD. MODESTLY STRONG UPPER WAVE
CONTINUES TO PROGRESS THROUGH WISCONSIN...WITH A NOTABLE 700-500MB
AXIS OF DEFORMATION FORCING ACTING TO ELONGATE A BAND OF RAIN OVER
MUCH OF THE AREA SOUTH OF M-72. PRONOUNCED LOW LEVEL THETA-E AXIS
RUNNING ACROSS THIS AREA IS ALSO SERVING TO PROMOTE SOME WEAK
INSTABILITY BENEATH COOLING MID LEVELS...WITH UP TO 500 J/KG
MUCAPE PER SHORT TERM RAP FORECAST RAOBS. AS SUCH...NO SURPRISE WE
ARE SEEING OCCASIONAL THUNDER BREAK OUT AS WELL.
HEADING INTO THE LATE MORNING/AFTERNOON...SUSPECT PERIODS OF
SHOWERS AND STORMS WILL CROSS MUCH OF THE SOUTHERN HALF OF THE
CWA...ALL WHILE EXPANSIVE LOW LEVEL RIDGING AND ASSOCIATED DRYING
PUT A DEFINITELY NORTHERN EDGE TO THE PRECIP SHIELD. PER SHORT
TERM GUIDANCE AND STRONG SREF HINTS...WILL TRIM THE NORTHERN TIER
OF HIGHER POPS...WITH AREAS CLOSER TO LAKE HURON (NORTH OF M-32)
AND JUST ABOUT ALL OF EASTERN UPPER PROBABLY OUT OF THE MIX FOR
MUCH OF THE DAY. IN ADDITION TO EXPECTED AXIS OF DEFORMATION
FORCING...WILL LIKELY ALSO SEE SOME DIURNAL HELP TO THE PRECIP
WITHIN A QUITE MOIST AIRMASS...WITH SURFACE TEMPS INTO THE
LOWER/MIDDLE 70S PROMOTING MUCAPE VALUES UP TOWARD 700 J/KG. GIVEN
THE UPPER COLD POOL SKIRTING OVERHEAD AND A GOOD CHUNK OF
AVAILABLE INSTABILITY SITUATED ABOVE THE -12C ISOTHERM...SMALL
HAIL REMAINS A THREAT WITH ANY CONVECTION THAT DEVELOPS.
PER SATELLITE TRENDS...HAVE LOWERED GOING HIGHS A COUPLE OF
DEGREES INLAND WITH ONGOING UPSLOPE FLOW INTO THE HIGHER TERRAIN
LIKELY CAPPING THINGS AROUND 70 DEGREES...WITH DOWNSLOPE FLOW INTO
NORTHWEST LOWER KICKING THINGS TOWARD THE MID 70S. WARMEST SPOTS
WILL BE EASTERN UPPER WITH THINNING CLOUDS INTO THE AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 409 AM EDT FRI JUL 27 2012
EARLY MORNING SURFACE ANALYSIS SHOWS AN EAST-WEST ORIENTED TROUGH
AXIS LYING ACROSS SOUTHERN LOWER MICHIGAN/CENTRAL WISCONSIN.
COMPACT UPPER LOW WAS SPINNING SOUTHEAST INTO NORTHWEST
WISCONSIN...WITH A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ARCING
AROUND THIS CIRCULATION FROM THE MICHIGAN/WISCONSIN BORDER SOUTHWARD
ACROSS EASTERN WISCONSIN (WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD AHEAD OF THIS LOW SPREADING ACROSS LAKE MICHIGAN).
MEANWHILE...A FEW SPOTTY RADAR RETURNS DEVELOPED NORTH OF THE
SURFACE TROUGH AXIS SOUTH OF THE M-55 CORRIDOR WHERE LOW LEVEL LAPSE
RATES WERE LIKELY A LITTLE STEEPER PER 00Z DTX SOUNDING.
UPPER LEVEL FEATURE WILL CONTINUE TO TRACK SOUTHEAST AND CROSS
SOUTHERN LOWER MICHIGAN DURING THE DAY. WEAK RIDGE OF HIGH PRESSURE
WILL BUILD INTO NORTHERN MICHIGAN IN THE WAKE OF THIS SYSTEM TONIGHT.
TRACK OF THE UPPER LEVEL LOW SUGGESTS HIGHEST PRECIPITATION CHANCES
TODAY WILL BE ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
WILL BENEFIT THE MOST FROM THE SYNOPTIC COMPONENT WHICH SHOULD
ARRIVE THIS MORNING...PLUS STRONGEST DIURNAL COMPONENT WHERE LOW
LEVEL MOISTURE WILL BE MAXIMIZED AND MAY RESULT IN MLCAPE VALUES IN
THE 1000J/KG RANGE. PRECIPITATION CHANCES WILL BECOME MORE
SCATTERED TO THE NORTH WITH DRIER LOW LAYERS...AND LOOKING LIKE MOST
OF EASTERN UPPER WILL PROBABLY ESCAPE WITH LITTLE SIGNIFICANT
PRECIPITATION. THERMAL THROUGH ASSOCIATED WITH UPPER LEVEL WAVE
WILL LOWER FREEZING LEVELS...THUS STORMS WILL BE CAPABLE OF
PRODUCING HAIL. PLAN TO CARRY AN EXPLICIT MENTION OF SMALL HAIL
SOUTH OF A CVX-OSC LINE FROM LATE MORNING ONWARD. WARMEST HIGHS
TODAY WILL PROBABLY BE NORTH OF THE BRIDGE WHERE THERE WILL BE MORE
SUN ESPECIALLY LATER TODAY...IN GENERAL EXPECT HIGHS MAINLY IN THE
70S.
AS UPPER WAVE SLIPS INTO THE OHIO VALLEY THIS EVENING AND DRIER AIR
FILTERS INTO NORTHERN MICHIGAN IN ITS WAKE...THREAT FOR SHOWERS WILL
COME TO AN END ACROSS CENTRAL LOWER COUNTIES WITH SKIES CLEARING.
MAYBE A LITTLE PATCHY FOG ACROSS PARTS OF NORTHERN LOWER...BUT
SHOULD BE A SEASONABLY CHILLY NIGHT. COULD SEE A FEW SHELTERED
SPOTS DROPPING BELOW 50 EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM EDT FRI JUL 27 2012
CURRENT UPPER LEVEL PATTERN SET TO CHANGE LITTLE FOR THE FORESEEABLE
FUTURE...FEATURING INTERMOUNTAIN WEST/HIGH PLAINS RIDGING BOOKENDED BY
EASTERN NOAM AND FAR EAST PACIFIC TROUGHINESS. AS A RESULT...
RECENTLY ESTABLISHED NORTHWEST FLAVOR TO MID LEVEL FLOW OVER THE
LAKES WILL REMAIN REMARKABLY PERSISTENT...KEEPING TEMPERATURES
LOCKED IN TO NEAR NORMAL LEVELS AND ALLOWING PERIODIC RAIN CHANCES
AS OCCASIONAL DISTURBANCES ROTATE THROUGH THE REGION. FORECAST
CONCERNS RELEGATED TO THE LATTER OF THESE TWO...FOCUSING ON SHOWER
AND STORM CHANCES NEXT WORK WEEK.
RESERVOIR OF DRY CANADIAN AIR SWEEPS SOUTH INTO THE NORTHERN LAKES
BEHIND TOMORROWS DEPARTING SYSTEM...SETTING UP A MAINLY QUIET...DRY
WEEKEND. OVERHEAD HIGH PRESSURE EXPECTED TO LEAD TO EXCELLENT LAKE
BREEZE DEVELOPMENT SATURDAY...AND COMBINED WITH LINGERING 850MB
THERMAL TROUGH...SHOULD SET UP A PRETTY DECENT INLAND CU FIELD BY
AFTERNOON. FORMIDABLE MID LEVEL CAP EXPECTED TO KEEP CLOUD HEIGHTS
IN CHECK AND PREVENT ANY SHOWER DEVELOPMENT. LATEST PROGS STARTING
TO THROW SOME CONCERN INTO INHERITED DRY SUNDAY... ESPECIALLY ACROSS
EASTERN UPPER. SUBTLE MID LEVEL WAVE AND BEGINNINGS OF MODEST RETURN
FLOW NOW SUPPORTING SOME EASTERN UPPER SHOWERS BY AFTERNOON.
GUIDANCE IS NOTORIOUS FOR BRINGING IN MOISTURE TOO QUICKLY...
ESPECIALLY WITH AN ANTECEDENT RELATIVELY DRY AIR MASS. WILL REFRAIN
FROM INTRODUCING ANOTHER PERIOD OF LOW END SHOWER POTENTIAL (SEE
BELOW)...WAITING FOR MORE CONSISTENCY BEFORE DOING SO. NEAR SEASONAL
HIGH TEMPERATURES EXPECTED BOTH AFTERNOONS...WITH READINGS IN THE
UPPER 70S AND LOWER 80S.
"POTENTIALLY" SOMEWHAT MORE ACTIVE PERIOD OF WEATHER RETURNS NEXT
WORK WEEK...WITH ABOVE OUTLINED FLOW AT LEAST OPENING UP THE
OPPORTUNITY FOR A FEW DISTURBANCES TO ROTATE THROUGH THE REGION.
NOTHING EARTH SHATTERING PER TRENDS...WITH GUIDANCE SUGGESTING LOW
AMPLITUDE WAVES AND DEEPEST CORE OF MOISTURE TO REMAIN WELL TO OUR
SOUTHWEST. AS EXPECTED WITH THIS FLOW REGIME...EXACT TIMING REMAINS
PROBLEMATIC AT BEST...WITH THE ECMWF LAGGING BEHIND BOTH THE GFS AND
GEM BY SEVERAL HOURS WITH LEAD WAVE LATE SUNDAY NIGHT INTO MONDAY.
SIMPLY NOT PRUDENT AT THIS HOUR TO PICK ONE OVER THE OTHER...AND
WILL RIDE WITH LATE SUNDAY NIGHT INTO MONDAY LOW END RAIN CHANCES.
SAME GOES FOR MONDAY NIGHT AND TUESDAY AS ADDITIONAL SUPPORT
PINWHEELS OVER THE REGION. UNFORTUNATELY...BECAUSE OF SAID TIMING
CONCERNS...SIMPLY NO WAY TO SIDESTEP INHERITED MULTI-PERIOD RAIN
CHANCES...ALTHOUGH IN ALL LIKELIHOOD...MUCH OF THE TIME OUTLINED
ABOVE WILL REMAIN DRY. OF COURSE...TEMPERATURES DIRECTLY TIED TO
CONVECTIVE TRENDS...BUT OFF THE DECK THERMAL TRENDS SUGGEST HIGHS
BOTH MONDAY AND TUESDAY REMAINING IN THE UPPER 70S AND LOWER 80S.
PATTERN LOOKS TO SIMPLY REPEAT ITSELF LATER IN THE WEEK...WITH
TRENDS SUPPORTING A DRY MID WEEK PERIOD FOLLOWED BY ADDITIONAL RAIN
CHANCES THURSDAY INTO FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 132 AM EDT FRI JUL 27 2012
COMPLEX AND CHALLENGING CLOUD FORECAST THROUGH FIRST HALF OF TAF
PERIOD. AREAS OF MVFR FOG/LOWER CLOUDS OVERNIGHT...WITH INCREASING
CHANCES OF SHOWERS TOWARD 12Z AS UPPER LOW OVER WESTERN SUPERIOR
APPROACHES THE AREA. LOCALIZED IFR VSBY/S POSSIBLE DUE TO FOG
BEFORE THE SHOWERS ARRIVE. CIGS GENERALLY MVFR FOR THE FIRST HALF
OF FRIDAY WITH SCATTERED SHOWERS AND A FEW THUNDERSTORMS. CIGS
STEADILY IMPROVING BY LATER FRIDAY AFTERNOON AS UPPER LOW DEPARTS
AND DRIER AIR BEGINS TO MOVE IN FROM THE NORTHWEST.
WINDS LESS THAN 10 KNOTS THROUGHOUT THE NEXT 24 HOURS.
&&
.MARINE...
ISSUED AT 409 AM EDT FRI JUL 27 2012
EAST/NORTHEAST WINDS EXPECTED TODAY ACROSS THE UPPER LAKES...WITH
THE FORECAST AREA SANDWICHED BETWEEN A TROUGH OF LOW PRESSURE
DROPPING SOUTH TOWARD THE OHIO VALLEY AND A WEAK RIDGE OF HIGH
PRESSURE BUILDING IN FROM THE NORTH. WINDS WILL BACK MORE TOWARD
THE NORTH TONIGHT BUT GRADIENT WILL BE WEAKENING AS AFOREMENTIONED
RIDGE BUILDS IN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...JK
MARINE...JPB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
647 AM EDT FRI JUL 27 2012
.AVIATION...
//DISCUSSION...
NE FLOW OFF LAKE HURON HAS HELPED KEEP SURFACE MOISTURE ELEVATED
THUS HAS PRODUCED WIDESPREAD STRATUS. BETWEEN THE LOW STRATUS AND
LINGERING PATCHY FOG...MVFR CONDITIONS COULD CONTINUE FOR A COUPLE
MORE HOURS BEFORE LIFTING BACK TO VFR FOR THE AFTERNOON. THE STRATUS
HAS DONE A GOOD JOB KEEPING MOST OF THE FOG CONTAINED OVER SW LOWER
MI WITH HINTS OF IT APPROACHING FNT AND PTK AT TIMES. SURFACE LOW
PRESSURE SYSTEM APPROACHING LAKE MICHIGAN WILL REACH SE MI THIS
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS HAVE ALREADY STARTED
POPPING UP THIS MORNING BUT COVERAGE WILL INCREASE INTO THE
AFTERNOON AS DIURNAL HEATING AIDES IN THE DEVELOPMENT OF
PRECIPITATION. THIS MORNINGS COVERAGE WILL BE TOO ISOLATED TO
INCLUDE IN THE TAFS AT THIS TIME. HAVE CONTINUED THE MENTION OF
SHOWERS AFTER 18Z SINCE COVERAGE SHOULD BE MORE WIDESPREAD DURING
THAT TIME. WILL HOLD OFF ON MENTIONING THUNDER UNTIL WE CAN GET
BETTER TIMING OF THE STRONGER STORMS.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET AT LEAST
INTERMITTENTLY ON FRIDAY...BUT LOW CONFIDENCE ON TIMING.
* MEDIUM CONFIDENCE IN THUNDERSTORM DEVELOPMENT ON FRIDAY...BUT LOW
CONFIDENCE IN TIMING AND LOCATION.
&&
.PREV DISCUSSION...ISSUED 339 AM EDT FRI JUL 27 2012
SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1057 AM CDT FRI JUL 27 2012
.DISCUSSION...
HIGH PRESSURE NR DEVILS LAKE TO JAMESTOWN TO ABERDEEN LINE AT
15Z WITH LIGHT WINDS OVER THE FCST AREA. AREA OF LOW LEVEL
MOISTURE AND LOWER CLOUDS WHICH IS PICKED UP WELL BY 925 MB RH
FROM RAP MODEL HANGS ON FROM GRAND RAPIDS TO BEMIDJI MN SOUTHWARD.
THIS MODEL SHOWS SOME DECREASE IN RH DURING THE AFTN SO DO
EXPECTED CONTINUED SLOW BREAKUP INTO A BROKEN CU FIELD AS EVIDENT
BY CURRENT VSBL SATELLITE PIX. WILL INCREASE SKY COVER IN THAT
BJI-PKD-ADC AREA THRU 21Z TO ACCOUNT FOR BROKEN SKY CONDITIONS
THEN HAVE BETTER CLEARING LATE AFTN/EARLY EVE. LOWERED HIGH TEMPS
A FEW DEGREES IN THIS BAND WITH LOW TO MID 70S LIKELY
THERE...WHILE NR 80 MOST OTHER PLACES WHERE SUNSHINE MORE
PREVELENT. SOME CU STARTING TO FORM AS WELL ALONG THE WESTERN EDGE
OF THE RED RIVER VALLEY FROM MORDEN MANITOBA TO CAVALIER TO
LARIMORE ND DOWN TO WEST OF FARGO. SO EXPECT SOME CU EAST OF HIGH
PRESSURE RIDGE THIS AFTN....BUT SHOULD DISSIPATE AS WARMER AIR
ALOFT MOVES AS HIGH MOVES OVERHEAD AND MOVES EAST.
&&
.AVIATION...
BEMIDJI-PARK RAPIDS-WADENA AREA TO STAY IN BROKEN MVFR CU THRU
21Z...THEN SLOW CLEARING. OTHER TAF SITES VFR WITH SOME CU PSBL.
LIGHT WINDS ALL AREAS.
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT FRI JUL 27 2012/
SHORT TERM (TODAY-SUNDAY NIGHT)...MAIN CONCERNS WILL BE
TEMPERATURES AND THEN THUNDER CHANCES LATER IN THE PERIOD. 00Z
MODELS IN DECENT AGREEMENT WITH SYNOPTIC FEATURES AND WILL USE A
BLEND FOR DETAILS.
CURRENT CLOUD COVER ACROSS THE SOUTHEAST FA SHOULD CONTINUE TO
SLIDE TO THE SOUTH/SOUTHEAST.
SURFACE HIGH PRESSURE WILL MOVE THROUGH THE REGION TODAY AND
TONIGHT WITH RETURN FLOW SETTING UP ON SATURDAY. SOUTHERLY LOW
LEVEL FLOW WILL CONTINUE INTO SUNDAY BEFORE A BOUNDARY AND DRIER
AIRMASS MOVES INTO THE REGION SUNDAY NIGHT. WATER VAPOR IMAGERY
INDICATES MULTIPLE SHORTWAVES UPSTREAM THAT COULD AFFECT THE
REGION OVER THE NEXT FEW DAYS. TODAY WILL BE DRY AS ACTIVITY
SHOULD DISSIPATE AS IT APPROACHES THE LOW-LEVEL RIDGE. THERE WILL
BE LOW-END THUNDER CHANCES THROUGH THE WEEKEND...ALTHOUGH BEST
CHANCES APPEAR TO BE SUNDAY AFTERNOON/EVENING ACROSS THE NORTHERN
FA AS SFC BOUNDARY COINCIDES WITH PEAK HEATING AND INCREASED
MOISTURE. DEEP LAYER SHEAR WOULD BE SUFFICIENT FOR A STRONGER
STORM OR TWO IF CONDITIONS SET UP FAVORABLY.
TEMPERATURES WILL WARM A BIT EACH DAY...NEAR NORMAL TO SLIGHT
ABOVE NORMAL BY THE END OF THE PERIOD.
LONG TERM (MONDAY-THURSDAY)...REGION WILL REMAIN IN ELEVATED NW
FLOW PATTERN THROUGH THE LONG RANGE PERIOD. MAIN CHALLENGE WILL BE
TIMING OF WEAK IMPULSES ROUNDING RIDGE PROVIDING LIGHT PCPN
CHANCES. AS EXPECTED MODELS DIFFER ON TIMING OF ANY WEAK FEATURES
MAKING ANY FINE TUNING OF POPS DIFFICULT. FOR THIS WILL MAINTAIN
LOW POPS ON AND OFF THROUGH THE PERIOD. TEMPERATURES WILL BE ABOVE
SEASONAL AVERAGES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1148 AM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND
EVENING. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE NORTHWEST
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPR LVL S/WV LOCATED OVER THE WRN GREAT LAKES THIS MORNING WILL
PIVOT SE ACRS THE REGION LATE THIS AFTN AND OVERNIGHT. AN AREA OF
WEAK LOW PRESSURE AND A SFC COLD FRONT WILL ACCOMPANY THIS FEATURE
AS THEY SLOWLY MOVE SOUTHEAST THROUGH THE REGION OVERNIGHT. THE
COMBINATION OF THESE FEATURES WILL INTERACT WITH A MOIST AND
UNSTABLE AIRMASS THIS AFTERNOON AND EVENING...RESULTING IN
CONVECTIVE DEVELOPMENT FROM EARLY AFTERNOON INTO THE EVENING
HOURS. LATEST HRRR AND NAM SUGGEST THAT CONVECTION WILL GET GOING
ACRS NRN AND CENTRAL INDIANA EARLY THIS AFTERNOON...AND SHOULD
PROPAGATE SE THROUGH OUR AREA THIS AFTERNOON INTO THIS EVENING.
WITH BULK SHEAR IN THE 25 TO 35 KNOT RANGE...STORMS SHOULD EXHIBIT
SOME ORGANIZATION WITH MULTICELLS PERHAPS MERGING INTO LINEAR
BOWING SEGMENTS. IN ADDITION...WITH THE SFC LOW APPROACHING OUR NW
CWFA...THERE WILL BE SOME DIRECTIONAL SHEAR THAT MAY CAUSE A FEW
STORMS TO ROTATE. AS A RESULT OF ALL THESE FACTORS...HAVE GONE
WITH LIKELY POPS THIS AFTERNOON AND HAVE PLACED SEVERE WORDING IN
THE FORECAST. MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS
WITH SEVERE HAIL THE SECONDARY THREAT. AN ISOLATED TORNADO CAN NOT
BE RULED OUT...ESPECIALLY ACRS THE NWRN CWFA. ALTHOUGH STORMS WILL
HAVE SOME MOTION 20 TO 30 MPH AND RAINFALL RATES WILL NOT BE AS
HIGH AS YESTERDAY...OUR SE CWFA RECEIVED SUBSTANTIAL RAINFALL
AMOUNTS IN THE 3 TO 5 INCHES RAIN OVER THE LAST 24 HOURS. THIS HAS
RESULTED IN MOIST IF NOT NEARLY SATURATED SOILS IN THESE LOCALES.
1 HOUR FFG SUBSEQUENTLY ARE RANGING ANY WHERE BETWEEN A HALF INCH
TO AN INCH. GIVEN THIS SETUP...ANY STORMS THAT FORM TODAY...AND IF
THEY MOVE OVER THE SAME AREAS IN THE SE CWFA...THIS WILL LIKELY
RESULT IN AN INCREASED FLOOD THREAT...WITH THE POTENTIAL FOR FLASH
FLOODING. HAVE ISSUES A FLASH FLOOD WATCH FOR THE SE CWFA IN
EFFECT FROM 18Z THIS AFTN TO 08Z EARLY SATURDAY MORNING.
AS FOR TEMPERATURES AND DEWPOINTS...IT WILL BE ANOTHER VERY WARM
TO LOCALLY HOT DAY WITH HIGHS GENERALLY IN THE UPPER 80S TO THE
LOWER 90S AND DEWPOINTS IN THE MID 60S TO AROUND 70. THIS SHOULD
KEEP HEAT INDICES IN THE MID TO UPPER 90S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING INTO THE
EVENING ACROSS THE REGION PARTICULARLY IN THE EAST BEFORE MOVING
OFF AS THE COLD FRONT CONTINUES TO PROGRESS EASTWARD. INCREASED
LOW LEVEL MOISTURE AND WEAK COLD ADVECTION BEHIND THE FRONT SHOULD
RESULT IN THE DEVELOPMENT OF LOW CLOUDS THAT WILL LAST WELL INTO
SATURDAY MORNING. COULD STILL SEE A FEW SHOWERS AND THUNDERSTORMS
DEVELOP ON SATURDAY PRIMARILY IN THE NORTHERN COUNTIES WITH
HEATING AND A WEAK DISTURBANCE DROPPING INTO THE UPPER TROUGH. AS
HIGH PRESSURE BUILDS OVER THE AREA SATURDAY NIGHT AND SUNDAY...
CONDITIONS WILL BE QUIESCENT.
FOLLOWING RECENT TRENDS HAVE PATTERNED TEMPERATURE FORECAST NEAR
OR SLIGHTLY ABOVE WARMER MOS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE WEEK. THIS PATTERN
IS CONDUCIVE TO CONVECTIVE DEVELOPMENT AS DISTURBANCES DROP
SOUTHEAST. HOWEVER THESE DISTURBANCES ARE OFTEN DIFFICULT TO TRACK
AND TIME. AT THIS POINT HAVE INCLUDED LOW CHANCE POPS MAINLY
DURING THE DAYTIME PERIODS. TEMPERATURES WILL REMAIN ABOVE NORMAL.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SOME MVFR FOG WILL BE POSSIBLE AT THE START OF THE TAF PERIOD
HOWEVER EXPECT VSBYS TO IMPROVE TO VFR BY 13Z. IN ADDITION SOME
IFR CIGS WILL LINGER AT KILN THROUGH 13Z. A COLD FRONT WILL
APPROACH THE TAF SITES TODAY ALLOWING FOR SCATTERED SHOWER AND
THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND INTO THE EARLY EVENING
HOURS. DUE TO UNORGANIZED NATURE OF CONVECTION HAVE LIMITED
THUNDERSTORM MENTION TO VCTS FOR A FEW HOURS LATER THIS AFTERNOON.
THUNDERSTORMS WILL TAPER OFF THIS EVENING. LOW CLOUDS WILL MOVE
INTO THE AREA TAF SITES AGAIN TONIGHT. IN ADDITION...SOME FOG WILL
DEVELOP AS WELL ACROSS THE TAF SITES TONIGHT.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ079>082-088.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ098>100.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...
LONG TERM...
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1044 AM EDT FRI JUL 27 2012
.SYNOPSIS...
MOISTURE WILL BE ON THE INCREASE TODAY AHEAD OF AN APPROACHING WEAK
COOL FRONT. THIS FRONT WILL SETTLE OVER THE REGION DURING THE
WEEKEND AND GRADUALLY DISSIPATE. ANOTHER WEAK FRONT IS EXPECTED TO
APPROACH THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM...MOST COMPLICATED PART OF THE FORECAST AS USUAL DURING THE
SUMMER IS THE CONVECTIVE COMPONENT. THERE WILL CERTAINLY BE SOME
DEEP CONVECTION THIS AFTERNOON...BUT THERE ARE COVERAGE AND
INTENSITY QUESTIONS. THE MESO MODELS LIKE THE HRRR AND RAP GEN UP
CONVECTION EARLY THIS AFTERNOON IN THE LEE OF THE MOUNTAINS IN
WESTERN NC APPARENTLY RESPONDING TO WEAK VORT MX MOVING MOVING
THROUGH UPSTATE SC. SOME MID LEVEL CLOUDS ARE SHOWING UP THERE SO
THIS BASIC IDEA LOOKS REASONABLE. THE HRRR MOVES THIS INITIAL
CLUSTER SE WITH LITTLE DEVELOPMENT IN ITS WAKE. THE 12Z NAM HAS A
SIMILAR IDEA THOUGH MORE COVERAGE. I AM INCLINED TO BELIEVE THEIR
WILL BE MORE COVERAGE THAN WHAT THE HRRR IMPLIES...ACTUALLY MORE
ALONG THE LINES OF THE NAM AND OUR LOCAL WRF. HENCE...HAVE
TRENDED THE POP FIELD IN THE MORE GENEROUS DIRECTION FOR TODAY.
TEMP TRENDS LOOK BANG ON FOR THE MOST PART SO ONLY MINOR CHANGES.
CURRENT HEAT ADVISORY ACROSS THE SOUTHERN PIEDMONT LOOKS WELL
PLACED AND WILL CONTINUE THAT.
IN REGARD TO THE SEVERE THREAT FOR TODAY...THE MID LEVEL FLOW WILL
BE MUCH BETTER TO THE N OF OUR AREA THIS AFTN...BUT 500 MB WINDS
COULD APPROACH 25 KT ACROSS THE FAR NRN TIER WHICH WOULD SUPPORT A
MULTICELL MODE THERE. FARTHER TO THE SOUTH...THE STRONGLY HEATED
BOUNDARY LAYER WILL PRODUCE CAPES INCREASING TO 1500-2000J WHICH
WILL SUPPORT A PULSE SEVERE THREAT PRIMARLY FOR WET MICROBURSTS.
SPC HAS PLACED THE AREA IN A SLIGHT RISK AREA.
EXPECT THAT CONVECTION SHOULD WANE QUICKLY THIS EVENING THANKS TO
WEAK NVA BEHIND DEPARTING VORT MAX. QUICK PEAK AT 12Z NAM SUPPORTS
THIS SCENARIO. WILL MAKE SOME ADJUSTMENTS TO TONIGHT`S POP GRIDS
MASED ON 12Z NAM. ANOTHER WARM AND MUGGY NIGHT IS IN STORE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...THE MODELS APPEAR TO AGREE IN SHUNTING THE
DEEPER MOISTURE TOWARD THE COASTAL PLAIN BY SATURDAY AFTERNOON.
HOWEVER...THERE IS SLIGHT DISAGREEMENT ON THE POSITION OF THE
SURFACE BOUNDARY...AND A MAJOR DISCREPANCY BETWEEN THE GFS AND THE
NAM ON THE DISTRIBUTION OF INSTABILITY ACROSS THE REGION SAT
AFTERNOON. THE GFS HAS A VERY SHARP CAPE GRADIENT...WITH VERY LITTLE
IN THE WAY OF INSTABILITY WEST OF THE FRONTAL ZONE (I.E. VERY LITTLE
INSTABILITY IN OUR AREA). MEANWHILE...THE NAM DEPICTS A MORE DIFFUSE
SURFACE BOUNDARY...WITH PLENTY OF LOW-LEVEL MOISTURE LINGERING TO
SUPPORT HIGH CAPE VALUES ACROSS THE CWA. CONSIDERING THE TIME OF
YEAR...AND EXAMINING CURRENT OBS WEST OF THE FRONTAL BOUNDARY...I
HAVE A DIFFICULT TIME BUYING IN TO THE GFS INSTABILITY PICTURE. THIS
HAS MAJOR FORECAST IMPLICATIONS...AS BOTH MODELS FEATURE A RATHER
POTENT SHORT WAVE TROUGH TRAVERSING THE AREA DURING THE AFTERNOON.
WITH THE LONG WAVE TROUGH AXIS OVERHEAD...THERE SHOULD BE A DECENT
AMOUNT OF DEEP LAYER SHEAR (25-30 KT)...AND THE SHORT WAVE COULD
PROMOTE DEVELOPMENT OF ORGANIZED CONVECTION DURING PEAK HEATING. IN
FACT...THE NAM IS DOING JUST THAT. IN LIGHT OF THE VERY DRY
MID-LEVELS ALONG WITH MODERATE DEEP LAYER SHEAR...CONVECTION MAY
TEND A LITTLE TOWARD DISCRETE CELLS...SO IM NOT PREPARED TO MAKE
MAJOR INCREASES IN POPS...BUT THEY HAVE BEEN INCREASED TO 30-40
PERCENT FROM THE BLUE RIDGE EAST. FORECAST SOUNDINGS DEPICT VERY
HIGH VALUES OF DCAPE...SO DAMAGING MICROBURSTS WOULD BE OF PRIMARY
CONCERN.
ANY CONVECTION WILL SWEEP EAST WITH THE SHORT WAVE SAT EVENING...
LEAVING MOSTLY DRY CONDITIONS THROUGH AT LEAST SUNDAY MORNING. THE
TROUGH AXIS REMAINS OVERHEAD SUNDAY...BUT RISING HEIGHTS IN THE WAKE
OF THE SHORT WAVE WILL RESULT IN GRADUALLY WEAKENING FLOW. IT
APPEARS THE BEST INSTABILITY WILL BE EAST OF THE AREA...BUT THERE
WILL BE MORE THAN ADEQUATE CAPE VALUES BENEATH DIFFLUENT FLOW ALOFT
TO SUPPORT ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON.
THE MODELS SUGGEST CONVECTION WILL LINGER INTO SUNDAY NIGHT...AS
MOISTURE DEEPENS IN RESPONSE TO THE APPROACH OF ANOTHER SHORT WAVE
TROUGH...SO AT LEAST SLIGHT CHANCES WILL EXIST ACROSS MUCH OF THE
AREA THROUGH THE OVERNIGHT. TEMPS WILL COOL SLIGHTLY BENEATH THE
UPPER TROUGH AXIS...BUT WILL STILL REMAIN AROUND NORMAL THROUGH THE
PERIOD.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 320 AM FRIDAY...THE MEDIUM RANGE WILL FEATURE VERY LITTLE
CHANGE IN THE SYNOPTIC PATTERN...AS GLOBAL MODELS AGREE THAT AN
EASTERN TROUGH WILL PERSIST THROUGH THE PERIOD. THEREFORE...AT LEAST
SCATTERED/MAINLY DIURNAL CONVECTION...OCCASIONALLY ENHANCED BY THE
PASSAGE OF WEAK SHORT WAVE TROUGHS...CAN BE EXPECTED THROUGH THE
PERIOD. IT ALSO APPEARS THAT A MORE SIGNIFICANT SHORT WAVE WILL PASS
OVER THE EASTERN CONUS TOWARD THE MIDDLE OF THE WEEK...BRINGING
ANOTHER COLD FRONT INTO THE AREA...ALTHOUGH THE TIMING OF THIS IS
UNCERTAIN. IN LIGHT OF THIS PATTERN...ABOVE CLIMO POPS AND NEAR
NORMAL TEMPS ARE WARRANTED THROUGH THE PERIOD.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...FEW TO SCT CIRRUS FROM NEARBY CONVECTION WILL PERSIST IN
THE TERMINAL AREA THIS MORNING. DEWPOINT POOLING ACROSS THE REGION
TODAY WILL THEN PERMIT CUMULUS DEVELOPMENT BY 17Z...WITH THE BEST
CHANCE OF TSRA TOWARD 21Z WITH THE PASSAGE OF A WEAK UPPER
SHORTWAVE. WINDS WILL BE SW LESS THAN 10 KT THROUGH THE
PERIOD...ALTHOUGH SOME BRIEF LOW END GUSTS TO THE LOWER TO MIDDLE
TEENS WILL BE POSSIBLE DURING PEAK MIXING. ACTIVITY WILL DISSIPATE
THIS EVENING WITH LINGERING DEBRIS CLOUDS INTO THE NIGHT.
ELSEWHERE...DEBRIS CLOUDINESS WILL PERSIST ACROSS THE REGION THIS
MORNING. THIS HAS KEPT THE FOG AT BAY...BUT BRIEF MVFR VSBY COULD
STILL OCCUR AT KAND...KAVL...AND KHKY. CUMULUS WILL DEVELOP BY 16Z
TO 18Z WITH HEATING AND DEWPOINT POOLING AHEAD OF AN APPROACHING
BOUNDARY. SCATTERED CONVECTION WILL THEN LIKELY DEVELOP BY 20Z TO
21Z WITH THE ARRIVAL OF A WEAK UPPER SHORTWAVE. EXPECT MAINLY SW
FLOW AT THE FOOTHILL SITES...WITH BRIEF LOW END GUSTS INTO THE LOWER
TO MIDDLE TEENS POSSIBLE AT TIMES...EXCEPT NW WINDS AT KAVL. DEBRIS
CLOUDS SHOULD LINGER INTO TONIGHT...WITH ANOTHER SHOT AT MVFR VSBY
TOWARD DAYBREAK...POSSIBLY IFR AT KAVL.
OUTLOOK...ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED ON SATURDAY AS
AN UPPER WAVE AND SFC COLD FRONT MOVE THROUGH THE REGION. A DAILY
CHANCE OF SCT AFTERNOON CONVECTION WILL THEN CONTINUE INTO THE
MIDDLE OF NEXT WEEK AS AN UPPER TROF REMAINS OVER THE AREA.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR GAZ029.
NC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ071-072-082.
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ009-011>014-
019.
&&
$$
SYNOPSIS...JDL
NEAR TERM...LG
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...HG
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
310 PM EDT FRI JUL 27 2012
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
MAIN FORECAST CONCERN IS THUNDERSTORM POTENTIAL THROUGH TOMORROW
ASSOCIATED WITH SEVERAL SHORTWAVES TRAVELING ALONG THE UPPER LEVEL
TROUGH SITUATED ACROSS THE EASTERN CONUS. A VERY MOIST AND UNSTABLE
ATMOSPHERE IS IN PLACE WITH MLCAPE VALUES OF NEAR 3000 J/KG AND PW
VALUES NEAR AND ABOVE 2.0 INCHES. SCATTERED SHOWER AND THUNDERSTORM
DEVELOPMENT HAS BEEN OCCURRING ACROSS THE FORECAST AREA EARLY THIS
AFTERNOON WITH A BIT BETTER ORGANIZED ACTIVITY ACROSS THE SOUTHERN
PORTION THAT INITIATED NEAR AN AREA OF ENHANCED BAROCLINICITY DUE TO
SOLAR SHELTERING FROM REMNANT CLOUD COVERAGE THIS MORNING. AMONG THE
ENSEMBLE OF AVAILABLE HI-RES GUIDANCE SOLUTIONS...THE HRRR SO FAR
HAS BEEN VERIFYING WELL WITH THE EARLY CONVECTIVE DEVELOPMENT AND IS
STARTING TO PICK UP MORE ON THE INFLUENCE OF THE SHORTWAVE IN THE
NORTHERN PORTION CLOSER TO 00Z THIS EVENING. THE WRF IS A BIT MORE
ROBUST WITH THIS LATER DEVELOPMENT. WILL THEREFORE EXPECT SEVERAL
ROUNDS OF DEVELOPMENT FROM THIS AFTERNOON THROUGH TONIGHT WITH THE
MORE ORGANIZED DEVELOPMENT AND GREATER SEVERE POTENTIAL OCCURRING
FROM ABOUT 23-02Z ACROSS THE NORTH. SPC ALSO HAS THIS AREA INCLUDED
IN A SLIGHT RISK. THE MAIN THREATS WILL BE STRONG WINDS AND HEAVY
RAINFALL WITH DOWNDRAFT CAPE ALREADY NEAR 1000 J/KG ACROSS THE NORTH
AND MUCH HYDROMETEOR LOADING EXPECTED WITH SUCH A MOIST THERMAL
PROFILE. FREQUENT LIGHTNING AND SMALL HAIL WILL ALSO BE POSSIBLE.
ISOLATED SEVERE STORM POTENTIAL IS ACROSS THE SOUTH AS WELL AS THE
MORE ENHANCED MOISTURE FIELD RESIDES NEAR A PERSISTENT SFC TROUGH.
HAVE GONE WITH LIKELY POPS IN THE NORTH AND SOUTH FROM 21-00Z
TRENDING INTO CHANCE POPS TONIGHT AND DECREASING TO SLIGHT ACROSS
THE NORTH NEAR EARLY MORNING.
MAINTAINING CHANCE POPS ACROSS SOUTHERN PORTION OVERNIGHT AND
EXPANDING BACK ACROSS MAJORITY OF AREA ON SATURDAY AS THE NAM
SUGGESTS ANOTHER SHORTWAVE RIPPLING ALONG UPPER TROUGH. GUIDANCE IS
IN GENERAL AGREEMENT WITH THE MAIN TROUGH AXIS LINGERING NEAR THE
EASTERN PORTION OF THE AREA INTO SUNDAY. PORTIONS OF THE SOUTH AND
EAST WILL THEREFORE HAVE SLIGHT TO CHANCE POPS OVERNIGHT SATURDAY.
FOR TEMPS...BLEND OF MAV AND MET LOOKS REASONABLE WITH GENERALLY
LOWER TEMPS THAN PREVIOUS DAYS AND INCREASED CLOUD COVERAGE
EXPECTED. ATTM THE PROGGED TEMPS AND DEWPOINTS DO NOT MEET HEAT
ADVISORY CRITERIA FOR SATURDAY... SO AM CURRENTLY PLANNING ON NO
ADDITIONAL ISSUANCE.
BAKER
.LONG TERM /SUNDAY THROUGH FRIDAY/...
NOT MUCH CHANGE TO THE PREVIOUS GRIDS. DID INCREASE POPS ON SUNDAY
IN RESPONSE TO THE WEAK STATIONARY FRONT AND PROXIMITY OF THE
TROUGH AXIS...PROGGED TO BE PRETTY MUCH PARKED OVER THE
APPALACHIANS DURING THE DAY ON SUNDAY...WITH A SHORTWAVE PUSHING
INTO THE AREA. BEST CHANCES WILL BE IN THE SOUTHEAST HALF TO 2/3
OF THE FORECAST AREA...BUT CANNOT RULE OUT TOPOGRAPHICALLY-INDUCED
CONVECTION IN THE NORTHEAST MOUNTAINS. THE NAM GOES A LITTLE NUTS
WITH CONVECTION AS THE RESULT OF A VORT LOBE RIDING DOWN THE FLOW
ALOFT. ECMWF DOES ACTUALLY HAVE SOMETHING SIMILAR BUT WITH LESS
CONVECTIVE FEEDBACK AND THUS A MORE REASONABLE QPF FIELD.
OTHERWISE...ONLY MINOR CHANGES MADE TO THE EXTENDED PARTIALLY TO
ACCOUNT FOR NEW GUIDANCE MODERATING THE TEMPS SOMEWHAT MONDAY INTO
TUESDAY. SEE PREVIOUS DISCUSSION BELOW.
TDP
PREV DISCUSSION... /ISSUED 346 AM EDT FRI JUL 27 2012/
A COLD FRONT OVER THE CENTRAL GA AREA EARLY SUNDAY WILL LIKELY
BECOME STATIONARY...DISSIPATING INTO TUESDAY. DURING THIS TIME AN
UPPER TROUGH SETS UP OVER THE EASTERN STATES WITH NW FLOW
AFFECTING THE AREA AND THE POTENTIAL FOR SHORT WAVES IN THAT FLOW
TO BRING SOME AMOUNT OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THIS PATTERN LOOKS TO CONTINUE THROUGH THE REST OF THE LONG TERM
WITH INDICATIONS OF ANOTHER FRONT MOVING TO THE AREA ON THURSDAY.
AS THE UPPER TROUGH BECOMES BETTER ESTABLISHED AND DEEPENS OVER THE
AREA DURING MID WEEK OR SO...THIS SHOULD COOL HIGH TEMPERATURES
CLOSER TO NORMAL.
&&
.AVIATION...
18Z UPDATE...
MOSTLY VFR CONDITIONS EXPECTED AND REDUCED VSBYS POSSIBLE WITH ANY
CONVECTION. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN
DEVELOPING THIS AFTERNOON AND SHOULD CONTINUE INTO THIS EVENING
WITH ANOTHER MORE WIDESPREAD ROUND POSSIBLE CLOSER TO 00Z FOR THE
NORTHERN SITES. CURRENTLY INCLUDING TEMPO GROUP FOR -TSRA FROM
19-23Z TODAY WITH THE POTENTIAL FOR EXTENDING IT TO ABOUT 02Z
LATER ON. CIGS HAVE RAISED TO NEAR BKN040. THERE IS THE POTENTIAL
FOR MVFR CIGS NEAR 13Z TOMORROW WITH SOME LOW LEVEL MOISTURE...BUT
WILL GO FEW030 BECOMING SCT040 BY 15Z FOR NOW. WINDS MOSTLY WEST
BECOMING WNW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE IN DURATION OF CONVECTION TODAY AND CIGS OVERNIGHT.
HIGH CONFIDENCE ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 73 95 72 94 / 30 40 20 20
ATLANTA 74 93 75 92 / 30 40 10 20
BLAIRSVILLE 66 89 66 88 / 40 30 10 20
CARTERSVILLE 71 93 70 92 / 40 30 10 10
COLUMBUS 76 94 76 93 / 30 40 20 30
GAINESVILLE 72 91 73 93 / 30 30 20 20
MACON 74 94 74 94 / 30 40 20 30
ROME 71 94 70 93 / 30 30 10 10
PEACHTREE CITY 72 93 70 91 / 30 40 20 20
VIDALIA 76 95 76 94 / 30 40 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BLECKLEY...CRISP...DODGE...DOOLY...EMANUEL...HOUSTON...
JEFFERSON...JOHNSON...LAURENS...MONTGOMERY...PULASKI...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.
&&
$$
SHORT TERM...BAKER
LONG TERM....TDP
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
204 PM EDT FRI JUL 27 2012
.PREV DISCUSSION... /ISSUED 1105 AM EDT FRI JUL 27 2012/
.UPDATE...
SHOWER AND ISOLATED THUNDERSTORM ACTIVITY HAS PERSISTED THIS MORNING
IN PARTS OF THE SOUTH. ANY LINGERING BOUNDARIES OR ENHANCED
BAROCLINITY DUE TO SOLAR SHELTERING FROM REMNANT CLOUD COVERAGE MAY
FOCUS SOME EARLIER REDEVELOPMENT THIS AFTERNOON. WHEN CONSIDERING
THE LATEST HI-RES SHORT TERM GUIDANCE... THE HRRR SOLUTION HAS A
BETTER HOLD ON SOME OF THE LINGERING CONVECTION IN THE SOUTH THIS
MORNING AND SUGGESTS SCATTERED REDEVELOPMENT ACROSS MUCH OF CENTRAL
AND NORTHERN GA AS EARLY AS 17Z. LATELY THE HRRR SEEMS TO BE A BIT
BULLISH WITH DEVELOPMENT EARLY ON. IT ALSO DOES NOT HAVE NEARLY AS
MUCH CONVECTION TRIGGER FROM THE IMPINGING UPPER SHORTWAVE TROUGH
FROM THE NORTH LATER...WHICH THE WRF BUYS INTO MORE. STILL THINKING
THE NORTH WILL HAVE BETTER CHANCES LATER DUE TO APPROACH OF UPPER
TROUGH...AND PARTS OF THE SOUTH WILL HAVE DECENT CHANCES AS WELL
WITH ENHANCED MOISTURE FIELD AND AFOREMENTIONED REMNANT MORNING
ACTIVITY. WILL MAINTAIN CHANCE POPS EARLY AREA-WIDE TRENDING TO
LIKELY POPS IN THE NORTH AND SOUTH FROM 21-00Z.
OTHERWISE...BUMPED DOWN TEMPS IN THE SOUTH DUE TO LINGERING
PRECIP/CLOUD COVERAGE AND MADE ADJUSTMENTS TO DEWPOINT TRENDS.
CHANGES STILL KEPT MUCH OF THE SOUTHERN PORTION WITHIN A FEW DEGREES
OF HEAT ADVISORY CRITERIA SO WILL MAINTAIN CURRENT PRODUCT. PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 346 AM EDT FRI JUL 27 2012/
HEAT ADVISORY FOR SOUTHEAST SECTIONS THIS AFTERNOON...
.SHORT TERM /TODAY THROUGH SATURDAY/...
LATEST SURFACE ANALYSIS OF THE SOUTHEAST SHOWS TROUGH REMAINS IN
PLACE ALONG THE EASTERN SEABOARD INTO THE CAROLINAS WITH SOME WEAK
RIDGING NOTED OVER WESTERN GEORGIA. ENHANCED CLUSTER OF STORMS
WHICH DEVELOPED OVER SOUTHERN SECTIONS LAST EVENING AND SENT
DEVELOPING OUTFLOWS NORTHWARD HAS LONG SINCE ABATED LEAVING BEHIND
MOSTLY CLOUDY CONDITIONS. MOST ALL OF THIS IS IN THE FORM OF HIGH
CLOUDS WITH NO LOW CLOUDS OF NOTE TO THE WEST EVEN THOUGH MODELS
ARE BULLISH ON THE FORMATION LATER TONIGHT INTO FRIDAY MORNING.
WITH YESTERDAYS ACTIVITY...ESPECIALLY LATE STORMS OVER THE
NORTH...ATMOSPHERE IS SLOWLY PROVING IT CAN SUSTAIN CONVECTION
WITH DECAYING RIDGE. TODAY LOOKS TO BE A TRANSITION DAY FOR THE
AREA AS TROUGH BECOMES MORE ENTRENCHED INTO THE TENNESSEE VALLEY
ALLOWING FOR FURTHER BREAKDOWN OF THE RIDGE. BASED ON MOISTURE
DISTRIBUTION...WITH ENHANCED LOW LEVEL MOISTURE FROM COLUMBUS TO
MACON...FEEL THESE AREAS WILL SEE INITIATION FIRST WITH AREAS TO
THE NORTH RECEIVING A LATER START AS SHORTWAVE ENERGY APPROACHES.
CAPE VALUES AREA WIDE LOOK TO BE IN THE 3000 PLUS RANGE THIS
AFTERNOON AND WITH BETTER SYNOPTIC SETUP...HAVE GONE 10 TO 30
PERCENT ABOVE GUIDANCE FOR MOST AREAS.
ALTHOUGH TIMING OF STORMS WILL BE KEY...STILL LOOKING AT SOUTHEAST
SECTIONS POSSIBLE SEEING HEAT INDICES IN EXCESS OF 105 THIS
AFTERNOON AND HEAT ADVISORY WILL BE POSTED.
AS FAR AS SEVERE POTENTIAL TODAY...ISOLATED SEVERE STORMS WILL BE
POSSIBLE AREA WIDE BUT APPEARS BEST CHANCE FOR ORGANIZED SEVERE
WILL BE TO THE NORTH WITH APPROACHING UPPER LEVEL ENERGY.
DOWNDRAFT CAPE NOT ALL THAT IMPRESSIVE TODAY WITH VALUES LESS THAN
500 J/KG FOR THE MOST PART BUT PRECIPITATION LOADING ALONE WILL
STILL LEAD TO ISOLATED STRONG TO SEVERE STORMS. TEMPS ALOFT WILL
NOT BE ESPECIALLY COLD EITHER WITH 500 TEMPS AROUND -6C TO -7C BUT
AGAIN...SOME ISOLATED SEVERE HAIL POSSIBLE AS WAS THE CASE LAST
NIGHT.
FOR SATURDAY...MODELS ALL WANT TO PUSH FRONTAL BOUNDARY INTO
SOUTHERN SECTIONS OF THE FORECAST AREA AND KEEP NORTHERN SECTIONS
DRY. STRONG SHORTWAVE ARRIVES LATE IN THE DAY HOWEVER FOR THE
NORTH AND FEEL ENOUGH MOISTURE WILL BE PRESENT ALONG WITH
CONTINUED HIGH INSTABILITY TO WARRANT LOW END CHANCE POPS FROM
ATLANTA NORTHWARD. CONTINUED STEAMY TO THE SOUTH IN VICINITY OF
THE FRONT AND DEPENDING ON HOW TODAY FARES...MAY NEED ANOTHER HEAT
ADVISORY FOR SATURDAY AS WELL.
DEESE
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT OVER THE CENTRAL GA AREA EARLY SUNDAY WILL LIKELY
BECOME STATIONARY...DISSIPATING INTO TUESDAY. DURING THIS TIME AN
UPPER TROUGH SETS UP OVER THE EASTERN STATES WITH NW FLOW
AFFECTING THE AREA AND THE POTENTIAL FOR SHORT WAVES IN THAT FLOW
TO BRING SOME AMOUNT OF SHOWERS AND THUNDERSTORMS TO THE AREA.
THIS PATTERN LOOKS TO CONTINUE THROUGH THE REST OF THE LONG TERM
WITH INDICATIONS OF ANOTHER FRONT MOVING TO THE AREA ON THURSDAY.
AS THE UPPER TROUGH BECOMES BETTER ESTABLISHED AND DEEPENS OVER THE
AREA DURING MID WEEK OR SO...THIS SHOULD COOL HIGH TEMPERATURES
CLOSER TO NORMAL.
BDL
&&
.AVIATION...
18Z UPDATE...
MOSTLY VFR CONDITIONS EXPECTED AND REDUCED VSBYS POSSIBLE WITH ANY
CONVECTION. SCATTERED SHOWER AND ISOLATED THUNDERSTORMS HAVE BEEN
DEVELOPING THIS AFTERNOON AND SHOULD CONTINUE INTO THIS EVENING
WITH ANOTHER MORE WIDESPREAD ROUND POSSIBLE CLOSER TO 00Z FOR THE
NORTHERN SITES. CURRENTLY INCLUDING TEMPO GROUP FOR -TSRA FROM
19-23Z TODAY WITH THE POTENTIAL FOR EXTENDING IT TO ABOUT 02Z
LATER ON. CIGS HAVE RAISED TO NEAR BKN040. THERE IS THE POTENTIAL
FOR MVFR CIGS NEAR 13Z TOMORROW WITH SOME LOW LEVEL MOISTURE...BUT
WILL GO FEW030 BECOMING SCT040 BY 15Z FOR NOW. WINDS MOSTLY WEST
BECOMING WNW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE IN DURATION OF CONVECTION TODAY AND CIGS OVERNIGHT.
HIGH CONFIDENCE ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 94 73 94 72 / 40 30 30 20
ATLANTA 93 74 92 74 / 50 30 30 10
BLAIRSVILLE 90 66 88 67 / 60 40 30 10
CARTERSVILLE 92 72 93 68 / 60 40 30 10
COLUMBUS 95 75 94 76 / 60 30 30 20
GAINESVILLE 92 73 91 72 / 50 30 30 20
MACON 94 74 95 73 / 60 30 30 20
ROME 93 71 95 68 / 60 30 30 10
PEACHTREE CITY 93 71 92 70 / 50 30 30 20
VIDALIA 94 76 94 75 / 40 30 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BLECKLEY...CRISP...DODGE...DOOLY...EMANUEL...HOUSTON...
JEFFERSON...JOHNSON...LAURENS...MONTGOMERY...PULASKI...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.
&&
$$
SHORT TERM...DEESE/BAKER
LONG TERM....BDL
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 PM CDT FRI JUL 27 2012
.SYNOPSIS...
12Z UA ANALYSIS HAD AN 850MB LOW NEAR KGRB WITH AN OCCLUDED FRONT
RUNNING INTO SOUTHWEST LOWER MICHIGAN. THE 850MB COLD FRONT RAN
FROM SOUTHWEST LOWER MICHIGAN INTO SOUTHERN NEBRASKA. SATELLITE
AND RADAR TRENDS THROUGH MID AFTERNOON SHOW PLENTY OF DIURNAL CU
WITH SHRA/TSRA ACROSS WISCONSIN.
18Z SFC ANALYSIS HAS A LOW NEAR KMKG WITH A COLD FRONT RUNNING
SOUTHWEST TO THE KSTL AREA AND THEN INTO NORTHEAST OKLAHOMA.
SEVERAL TROFS WERE BEHIND THE COLD FRONT FROM CENTRAL ILLINOIS
BACK NORTH INTO CENTRAL WISCONSIN. DEW POINTS WERE IN THE 50S AND
60S BEHIND THE FRONT WITH 60S AND 70S ACROSS THE OHIO VALLEY AND
DEEP SOUTH.
&&
.SHORT TERM...TONIGHT AND SATURDAY
THE FIRST QUESTION IS WILL DIURNAL CONVECTION DEVELOP LATE THIS
AFTERNOON. THE 20Z OBS INDICATE THE NORTHEAST CWFA IS WITHIN A FEW
DEGREES OF CONVECTIVE TEMPERATURE. IF CONVECTIVE TEMPERATURE CAN
BE REACHED BY 22Z AND A PARCEL CAN BE LIFTED TO THE LFC...
CONVECTION SHOULD ENSUE THAT DISSIPATES WITH SUNSET. RAP TRENDS
SHOW A WEAK THETA E GRADIENT DEVELOPING FROM ABOUT KPDC TO KSQI
WITH SOME FORCING ALONG IT. RADAR ALSO SHOWS SOME VERY WEAK
RETURNS BETWEEN KEFT AND KOVS IN SOUTHERN WISCONSIN.
SO...ALTHOUGH THE CHANCES ARE NOT GREAT...PROBABLY 1 IN 3... WILL
ADD A MENTION OF ISOLATED SHRA/TSRA VERY LATE THIS AFTERNOON UP TO
SUNSET. AT BEST THERE MAY ONLY BE A HANDFUL OF CELLS THAT DEVELOP.
IF NO CONVECTION DEVELOPS BY 2230Z...THE LATE AFTERNOON AND
EVENING IN THE NORTHEAST CWFA WILL LIKELY REMAIN DRY.
AS HIGH PRESSURE BUILDS INTO THE AREA LATE TONIGHT WINDS WILL
DIMINISH. AS TEMPERATURES DROP THE QUESTION THEN TURNS TO FOG
POTENTIAL. WHAT LITTLE RAIN THAT HAS OCCURRED RECENTLY HAS DONE
LITTLE TO MOISTEN THE GROUND. HOWEVER...A READY SOURCE OF MOISTURE
IS THE RIVERS. AN APPROACHING VORT MAX FROM THE PLAINS MAY ALLOW
SOME HIGH LEVEL CLOUDS TO SPILL INTO THE AREA PRIOR TO DAWN AND ANY
FOG DEVELOPMENT WILL BE VERY PATCHY. THUS WILL MENTION SOME PATCHY
RIVER VALLEY FOG IN THE NORTHERN CWFA LATE TONIGHT AND EARLY
SATURDAY MORNING.
MCS AND LIFT TOOLS ALL INDICATE A RESPECTABLE MCS SHOULD FIRE
TONIGHT IN THE PLAINS AND HEAD EAST. CLOUDS FROM THIS MCS SHOULD
SLOWLY OVERTAKE THE CWFA SATURDAY MORNING.
SATURDAY AFTERNOON...THE BETTER MOISTURE AND SUPPORT REMAIN WEST
OF THE CWFA PER THE MCS AND LIFT TOOLS. HOWEVER...DIURNAL HEATING
ON ANY OUTFLOW BOUNDARY FROM THE NOCTURNAL MCS SHOULD HELP
INITIATE CONVECTION IN CENTRAL IOWA THAT SLOWLY MOVES EAST. SO...
SCHC POPS FOR ISOLATED CONVECTION WILL BE ADDED TO THE FAR WESTERN
CWFA LATE SATURDAY AFTERNOON. TEMPERATURES ON SATURDAY SHOULD
AGAIN BE CLOSE TO NORMAL. ..08..
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY
SATURDAY NIGHT WILL BE VERY INTERESTING. SEVERAL MODELS HAVE
INDICATIONS THAT AN MCS WILL FORM IN NORTH CENTRAL OR NORTHWEST
IOWA...ALONG AN INSTABILITY GRADIENT AND 850MB BAROCLINIC ZONE. THE
MODELS HAVE A LOT OF DIFFERENCES IN WHERE THE SURFACE FEATURES AND
QPF ARE FOR THIS EVENT...BUT THE MID LEVEL BAROCLINIC ZONE IS FAIRLY
SIMILAR...WHICH FAVORS THE NORTHWEST OR NORTH CENTRAL IOWA LOCATION.
THIS POTENTIAL AREA OF CONVECTION WOULD SLIDE SOUTHEAST SATURDAY
NIGHT...AND AFFECT MAINLY THE WESTERN HALF OF THE FORECAST AREA LATE
SATURDAY NIGHT AND SUNDAY. HAVE RAISED POPS FOR THIS AREA...BUT
HAVE STILL LEFT IN THE CHANCE CATEGORY AND WILL LET LATER SHIFTS
RE-EVALUATE. HAVE ALSO KEPT HIGH TEMPERATURES IN THE 80S TO NEAR 90
SUNDAY...KNOWING THAT IF THIS EVENT IS MORE WIDESPREAD THAN
ANTICIPATED...THIS FORECAST WILL BE TOO WARM.
SUNDAY NIGHT MODELS TRY TO START ANOTHER MCS SOMEWHERE IN THE
GENERAL VICINITY...BUT MCS TECHNIQUES ARE LESS FAVORABLE AND WOULD
INDICATE A LOCATION FARTHER EAST OR SOUTH. SO...HAVE KEPT POPS IN
THE SLIGHT OR LOW END CHANCE POP RANGE FOR SUNDAY NIGHT AND MONDAY FOR
NOW...AND WILL LET LATER SHIFTS REEVALUATE. WHAT HAPPENS SATURDAY
NIGHT AND SUNDAY WILL STRONGLY AFFECT WHAT HAPPENS SUNDAY NIGHT.
HIGH TEMPERATURES SHOULD INCREASE AS MID LEVEL WARM AIR SURGES IN
OUR DIRECTION...SO HIGHS SHOULD RANGE FROM THE UPPER 80S TO LOW 90S
WITH LOWS IN THE UPPER 60S TO LOW 70S.
TUESDAY THROUGH THURSDAY...GENERAL NORTHWEST FLOW ALOFT WITH THE
UPPER LEVEL RIDGE STALLED OUT WEST. DESPITE HAVING A SURFACE RIDGE
IN PLACE...THE MID LEVEL BAROCLINIC ZONE WILL BE IN THE GENERAL
VICINITY. A FEW PERIODS OF SHOWERS AND THUNDERSTORMS ARE POSSIBLE
IN THIS PERIOD...BUT IT IS TOUGH TO NARROW DOWN WHICH PERIODS OR
LOCATIONS WITH THE NECESSARY MESOSCALE FEATURES POORLY DEFINED AT
THIS TIME RANGE. THUS...AM CARRYING SEVERAL PERIODS OF JUST SLIGHT
CHANCE POPS. TEMPERATURES TO SLOWLY RISE THROUGH THE PERIOD...WITH
HIGHS BY THURSDAY IN THE UPPER 80S TO MID 90S. LOWS IN THE UPPER
60S TO LOW 70S.
FRIDAY THERE ARE SOME LARGE DIFFERENCES IN THE MODELS. IN THE
ECMWF...THE UPPER LEVEL RIDGE FLATTENS AGAIN...AND A SHORTWAVE
APPEARS TO DIVE ACROSS THE MIDWEST ON FRIDAY. THIS...COMBINED WITH
THE MID LEVEL BAROCLINIC ZONE COULD PRODUCE A DECENT LIGHT TO
MODERATE RAIN EVENT. HOWEVER...THE GFS STILL KEEPS THE UPPER LEVEL
RIDGE STRONG WITH NO RAIN IN SIGHT...SO CONFIDENCE IS NOT HIGH.
SO...KEPT FORECAST MAINLY DRY WITH NEAR NORMAL TEMPERATURES.
LE
&&
.AVIATION... /ISSUED 1240 PM CDT FRI JUL 27 2012/
VFR WX IS EXPECTED THROUGH 06Z/28. THERE IS A POSSIBILITY OF
DIURNAL CONVECTION DEVELOPING LATE THIS AFTERNOON MAINLY EAST OF
THE MISSISSIPPI RIVER. IF CONVECTION DOES DEVELOP IT SHOULD BE
ISOLD IN NATURE BUT MAY CONTAIN TSRA. KDBQ COULD BE AFFECTED BUT
VCSH AND VCTS WAS LEFT OUT OF THE 18Z TAF. AFT 06Z/28 MAINLY VFR
WX IS EXPECTED. THERE IS A POSSIBILITY OF MVFR VSBYS DVLPG DUE TO
FG. THE 18Z TAFS REFLECT A POSSIBILITY OF VSBY RESTRICTION WITH
6SM ARND SUNRISE AT ALL SITES. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1240 PM CDT FRI JUL 27 2012
.UPDATE...
LATER THIS AFTERNOON COULD BE INTERESTING.
SFC OBS SHOW A TROF ACROSS WISCONSIN FROM JUST NORTH OF KMKE BACK
TO THE MISSISSIPPI RIVER BETWEEN KOEO AND KRZN. THIS TROF IS MUCH
SHARPER THAN DEPICTED IN ANY OF THE SHORT RANGE MODELS. A VORT MAX
ASSOCIATED WITH THE TROF HAS RESULTED IN SHRA/TSRA OVER MAINLY
EASTERN WISCONSIN BUT RADAR DOES SHOW SOME WEAK SHRA FURTHER WEST
IN CENTRAL WISCONSIN.
RAP TRENDS SHOW CONVECTIVE TEMPERATURES BEING IN THE LOWER 80S
ACROSS THE NORTHERN CWFA DURING THE AFTERNOON HOURS WHICH IS
COINCIDENT WITH THE FCST MAX TEMPERATURES. ALTHOUGH WEAKER THAN A
FEW HOURS AGO...THE RAP ALSO BEGINS TO DEVELOP SOME CONVERGENCE
OVER NORTHWEST ILLINOIS/SOUTHWEST WISCONSIN LATE THIS AFTERNOON.
ADDITIONALLY...THERE IS A WEAK THETA E GRADIENT OVER THE AREA
ALONG WITH THE PRESENCE OF THE VORT MAX.
THUS THERE IS A POSSIBILITY THAT SOME ISOLATED SHRA/TSRA COULD
DEVELOP LATE THIS AFTERNOON IF PARCELS CAN BE LIFTED TO THE LFC.
IF THIS OCCURS...CONVECTION WOULD DEVELOP SINCE THERE IS NO CAP
ABOVE THE LFC. THE AREA WOULD BE ROUGHLY EAST OF A LINE FROM KPDC
TO KSQI OR KVYS. TRENDS FOR THIS AREA WILL NEED TO BE MONITORED
CLOSELY DURING THE AFTERNOON FOR THE POSSIBILITY OF DIURNAL
CONVECTION DEVELOPING. IF CONVECTION DOES DEVELOP...IT SHOULD
DISSIPATE AROUND OR SHORTLY AFTER SUNSET. ..08..
&&
.AVIATION...
VFR WX IS EXPECTED THROUGH 06Z/28. THERE IS A POSSIBILITY OF
DIURNAL CONVECTION DEVELOPING LATE THIS AFTERNOON MAINLY EAST OF
THE MISSISSIPPI RIVER. IF CONVECTION DOES DEVELOP IT SHOULD BE
ISOLD IN NATURE BUT MAY CONTAIN TSRA. KDBQ COULD BE AFFECTED BUT
VCSH AND VCTS WAS LEFT OUT OF THE 18Z TAF. AFT 06Z/28 MAINLY VFR
WX IS EXPECTED. THERE IS A POSSIBILITY OF MVFR VSBYS DVLPG DUE TO
FG. THE 18Z TAFS REFLECT A POSSIBILITY OF VSBY RESTRICTION WITH
6SM ARND SUNRISE AT ALL SITES. ..08..
&&
.PREV DISCUSSION... /ISSUED 1014 AM CDT FRI JUL 27 2012/
UPDATE...
SHORTWAVE OVER NORTHEAST WISCONSIN WILL CONTINUE MOVING INTO
MICHIGAN THIS AFTERNOON. A VORT MAX DROPPING DOWN IS HELPING TO
MAINTAIN THE LOW CLOUDS ACROSS MN/WI. SATELLITE TRENDS INDICATE A
MORE CELLULAR NATURE TO THE CLOUDS IS OCCURRING SO THE SOUTHWARD
PROGRESS WILL SLOW. IMMEDIATE TRENDS ON SATELLITE THE PAST HOUR
SUGGEST SCT-BKN DIURNAL CU SHOULD DEVELOP OVER ROUGHLY THE NORTH
40 PERCENT OF THE CWFA FOR THE AFTERNOON WITH POSSIBLY SCT CU OVER
THE REMAINDER OF THE AREA.
REGARDLESS...THERE WILL BE MORE CLOUDS IN THE FAR NORTH/NORTHEAST
PARTS OF THE CWFA. SAID CLOUDS IN TURN WILL AFFECT TEMPERATURES
SOMEWHAT. DEEPER MIXING IS BEGINNING IN THE CLOUD FREE AREAS WHICH
SHOULD ALLOW DEW POINTS TO SLOWLY FALL THIS AFTERNOON.
TEMPERATURES SHOULD BE CLOSE TO NORMAL FOR MUCH OF THE CWFA THIS
AFTERNOON. THE POSSIBLE EXCEPTION MAY BE IN THE FAR SOUTHERN CWFA
WHERE SOME UPPER 80S MAY BE SEEN.
AN UPDATE REFLECTING THE CURRENT TRENDS SHOULD BE AVAILABLE BY
1030 AM. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
200 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA TODAY AND SLOWLY MOVE THROUGH
THE REGION TONIGHT. HIGH PRESSURE RETURNS SATURDAY AND REMAINS
INTO THE BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
...UPDATE TO INCLUDE SEVERE T-STORM WATCH FOR PORTIONS OF CENTRAL
VIRGINIA UNTIL 10 PM... PREVIOUS DISCUSSION FOLLOWS.
COLD FRONT CURRENTLY DRAPED FROM THE ERN GREAT LAKES ACROSS THE
PA/NY BORDER WILL SAG SOUTHEAST TOWARD THE CENTRAL MID ATLANTIC
TODAY. 12Z MODIFIED SOUNDING STILL SUPPORTS HIGH TEMPS IN THE MID
90S AT IAD...SO HIGH TEMP FORECAST FOR UPPER 90S IN DC/BALTIMORE
AREA STILL LOOKS VALID. TEMPS RUNNING A FEW DEGREES COOLER WEST OF
THE METRO AREAS DUE TO DEBRIS CLOUDS...BUT CLEARING TREND IS IN
PLACE LATE THIS MORNING.
SCATTERED SHOWERS HAVE DEVELOPED ALONG A PRE-FRONTAL TROUGH OVER
CENTRAL WV. 12Z NAM/09Z SREF SUPPORT THIS ACTIVITY BUILDING AND
MOVING EWD TOWARDS THE CWA THIS AFTN...BUT CLOUDS IN PLACE OVER WV
MAY LIMIT COVERAGE AND SEVERE THREAT. HRRR DOES NOT SUPPORT THIS
DEVELOPMENT...BUT INSTEAD FOCUSES CONVECTIVE INITIATION OVER THE
MOUNTAINS AND PIEDMONT EARLY THIS AFTERNOON. 12Z IAD SOUNDING
INDICATES SUFFICIENT SHEAR OVER THE REGION...AND IF SURFACE TEMPS
WARM AS FORECAST A 750MB CAP SHOULD BE BROKEN ALLOWING SB CAPE TO
REACH 2600 J/KG. SPC HAS A SLIGHT RISK OVER MOST OF VA AND MD EAST
OF THE BLUE RIDGE TODAY. MAIN THREAT WOULD BE DAMAGING
WINDS...ALTHOUGH A LARGE HAIL THREAT EXISTS AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
COLD FRONT SLOWLY SAG SOUTH TOWARD SERN VA WITH UPR TROUGH
REMAINING BACK OVER THE OH VLY. SHOULD SEE A BREAK IN PRECIP FOR
I-95 AND WEST /NOTE THE WEST/ BY THE EVENING...WITH PRECIP
PERSISTING EAST/SOUTH OF I-95 WELL INTO THE OVERNIGHT. MIN TEMPS MID
60S PIEDMONT AND WEST...LOW TO MID 70S I-95 AND EAST.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE ULTRA HIGH TEMPS WL BE HELD AT BAY DURG THE XTND PD. THIS IS
FREQUENTLY THE TIME OF YR WHEN THE "FOUR CORNERS HIGH" DVLPS OVR THE
SWRN U.S. ...AND THIS APPEARS TO BE THE CASE IN ALL OF THE XTND
MDLS. BECAUSE OF THIS THE ERN U.S. WL BE UNDER A SLT UPPER TROF.
THIS WL KEEP THE REALLY HOT WX...AND THE 70+ DWPTS...AT BAY FOR
THE FINAL DAYS OF JUL AND THE BEGINNING OF AUG. IN THE MID
ATLC...XPCT MOST OF THE XTND PD TO HV HIGH TEMPS IN THE MU80S.
LOWS RANGING FM THE L70S IN THE CITIES TO THE U50S IN THE
HIGHLANDS...BUT THE MAJORITY OF WL HV LOWS IN THE M60S.
THERE ISN`T MUCH TO HANG ONTO REGARDING POP CHCS. W/ ERN TROF IT
IS PSBL THAT A BNDRY COULD DVLP SOMETIME NEXT WK AND SERVE AS A
FOCUS FOR TSTM DVLPMNT...OTHERWISE SCT AFTN TSTMS IS THE BEST CHC
FOR RAFL.
ONE DAY CLOSER TO THE END OF THE MONTH...THIS RMNS THE WARMEST JUL
(AVG TEMP) IN DC ON RECORD. IT`S AMAZING THAT #2 AND 3 ARE THE PRVS
TWO YRS...EVEN THO RECORDS GO BACK TO 1871. BWI - THIS JUL IS IN
THE #2 SLOT...0.2 DEGS BEHIND 2010. THIS JUL IS ALSO #1 FOR
IAD...0.5 DEG AHD OF LAST YR.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR THIS MORNING. BRIEF LIGHT RAIN EXPECTED AT KMRB BEFORE 13Z.
THUNDERSTORMS/POTENTIAL PERIODS OF IFR CONDS THIS AFTERNOON AHEAD
OF A COLD FRONT. SWLY/WLY FLOW AROUND 10 KT TODAY. COLD FRONT
SLOWLY CROSSES TONIGHT WITH VFR CONDITIONS UNDER MID LEVEL CLOUDS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS SUNDAY BEFORE MOVING OFF
THE COAST FOR THE FIRST PART OF NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL INCREASE THE CHANCES FOR SHOWERS/TSTMS DURING THIS
TIME...HOWEVER NO WIDESPREAD SVR OUTBRK CAN BE SEEN ON THE
HORIZON.
&&
.MARINE...
WLY/SWLY FLOW AROUND 10 KT CONTINUE THROUGH TODAY. SCATTERED
THUNDERSTORMS EXPECTED LATE THIS AFTERNOON WELL INTO THE OVERNIGHT
WITH A DAMAGING WIND THREAT AHEAD/ALONG A SLOW MOVING COLD FRONT.
SURFACE HIGH PRESSURE WILL BUILD OVER THE WATERS SUNDAY BEFORE
MOVING OFF THE COAST EARLY NEXT WEEK. A RETURN FLOW AROUND THE
HIGH WILL IBRING ABT THE PSBLTY OF SCT SHOWERS/TSTMS NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR DCZ001.
MD...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MDZ006-007-011-
013-014-016>018.
VA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR VAZ052>057.
WV...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE...KCS
AREA FORECAST DISCUSSION...CORRECTED
NWS DETROIT/PONTIAC MI
333 PM EDT FRI JUL 27 2012
.SHORT TERM...THIS EVENING AND OVERNIGHT
CONVECTION HAS ERUPTED THIS AFTERNOON IN ADVANCE OF A MID LEVEL
SHORT WAVE IMPULSE NOW ROTATING INTO WRN LOWER MI. THE REGIONAL
WATER VAPOR LOOP INDICATES SMALLER SCALE CIRCULATIONS EMBEDDED
WITHIN THE SHORT WAVE...ONE NEAR MUSKEGON AND ONE OVER NW LOWER MI.
THE MID LEVEL WAVE WILL TRACK ACROSS SE MI THIS EVENING. DESPITE THE
EARLY ONSET OF CONVECTION...THE LARGER SCALE ASCENT ASSOCIATED WITH
THIS WAVE AND AMPLE LOW LEVEL MOISTURE WILL SUSTAIN CONVECTION INTO
AT LEAST EARLY EVENING. THUS FAR...SOME OF THE STRONGER STORMS HAVE
BEEN PRODUCING HAIL...INTENSE RAINFALL AND FREQUENT LIGHTNING. MID
LEVEL DRY AIR SHOWN ON THE WATER VAPOR LOOP SHOULD CONTINUE TO
SUPPORT SOME HAIL IN THE STRONGER CELLS. SLOW STORM MOVEMENT AND
PROLONGED LARGER SCALE FORCING WILL ALSO CONTINUE THE THREAT OF
LOCALIZED HEAVY RAINFALL. LENAWEE AND MONROE COUNTIES HAVE BEEN
PLACED IN A SEVERE THUNDERSTORM WATCH AS THEY ARE CLOSER TO THE
POOL OF BETTER INSTABILITY ACROSS THE OHIO VALLEY. STEEPER LOW
LEVEL LAPSE RATES AND STRONGER MID LEVEL WINDS NEAR THE OHIO
BORDER WILL ALSO PROVIDE AN OPPORTUNITY FOR STRONGER STORMS IN
THIS REGION. THE LATEST NAM AND RUC CONTINUE TO SUGGEST SOME
ENHANCEMENT IN MID TROPOSPHERIC DEFORMATION ALONG AND NORTH OF THE
I-69 CORRIDOR THROUGH EARLY EVENING AS THE CIRCULATION NEAR MKG
PUSHES EAST. THIS FORCING IS EXPECTED TO LINGER PAST 00Z BEFORE
SLOWLY WEAKENING AS IT MOVES EAST OF PORT HURON SHORTLY AFTER
MIDNIGHT...SUPPORTING DECREASING POPS THROUGH THE COURSE OF THE
NIGHT.
WEAK SFC LOW PRESSURE NOW LOCATED OVER NW OHIO WILL PUSH SOUTH
DURING THE NIGHT. SOME RESIDUAL SFC TROUGHING WILL LINGER OVER SE MI
INTO THE OVERNIGHT. THIS ALONG WITH NORTHEAST FLOW OFF LAKE HURON
AND THE DEVELOPMENT OF A WEAK SHALLOW INVERSION SHOULD ALLOW SOME
STRATUS REDEVELOPMENT TONIGHT. DRY AIR IS HOWEVER EXPECTED TO
IMPINGE ON THE SAGINAW VALLEY TOWARD DAYBREAK...WHICH MAY LEAD TO
SOME CLEARING NORTH OF FLINT LATE. THE POTENTIAL CLOUD COVER AND
INCREASING NERLY GRADIENT SHOULD HOLD MIN TEMPS MAINLY IN THE 60S
/WITH SOME 50S POSSIBLE IN THE TRI CITIES WHERE CLEARING IS POSSIBLE
PRIOR TO DAYBREAK/.
&&
.LONG TERM...SATURDAY THROUGH NEXT FRIDAY
SATURDAY BEGINS WITH THE EXIT OF THE MID-LEVEL WAVE AND SURFACE
PRESSURE TENDENCIES INCREASING ON THE ORDER OF 2-4 MB PER 6 HOURS.
LIFTED INDICES WILL BE WELL POSITIVE AND ANY LINGERING MOISTURE
CONTENT NEAR THE DETROIT RIVER WILL QUICKLY BE SCOURED OUT BY THE
APPROACHING HIGH PRESSURE. MORNING RH VALUES WILL BE HIGH ENOUGH TO
ALLOW FOR PATCHY AM FOG...OTHERWISE AN IDEAL SUMMER WEEKEND IS
EXPECTED. MAX TEMPERATURES WILL BE NEAR CLIMO NORMS AS A LOW
AMPLITUDE/LONGWAVE TROUGH SETTLES OVER THE REGION. BY SUNDAY NIGHT,
THE SURFACE HIGH WILL BE PUSHED EAST BY AN APPROACHING 100KT JET AND
SURFACE LOW.
THE GREAT LAKES REGION WILL REMAIN UNDER THE INFLUENCE OF A STABLE
NORTHWESTERLY FLOW CONFIGURATION ALOFT FOR MUCH OF NEXT WEEK. THE
NWP SOLUTION SPACE DOES DIVERGE SOMEWHAT TOWARD MIDWEEK...WITH THE
27.00 ECMWF BEING A BIT MORE AGGRESSIVE WITH RELEASING A PORTION OF
THE LONGWAVE RIDGE THROUGH THE UPPER MISSISSIPPI VALLEY INTO THE
WESTERN LAKES REGION. REGARDLESS OF THE SOLUTION VARIANCE...THE NET
RESULT WILL BE SEASONABLE CONDITIONS /NEAR TO SLIGHTLY ABOVE AVERAGE
TEMPERATURES/ WITH AN OCCASIONAL SHOT AT MEASURABLE PRECIPITATION.
CONSENSUS TIMING OF EMBEDDED SHORTWAVES WOULD SUGGEST THE BEST
CHANCES FOR RAINFALL WILL BE TUESDAY AND THURSDAY...BUT THAT WILL
CERTAINLY REQUIRE GREATER REFINEMENT GIVEN THE POOR RESOLUTION OF
THESE TRANSIENT FEATURES.
&&
.MARINE...
NORTHEASTERLY WINDS WILL INCREASE THIS EVENING AS LOW PRESSURE SINKS
SOUTH ACROSS THE OHIO VALLEY AND HIGH PRESSURE BUILDS OVER THE
NORTHERN GREAT LAKES. THIS ALONG WITH RECENT OBSERVATIONS OVER LAKE
HURON /ESPECIALLY SAGINAW BAY/ SUGGEST THESE WINDS ARE GOING TO KICK
UP SOME FAIRLY GOOD WAVE HEIGHTS THIS EVENING...PROMPTING THE
ISSUANCE OF SMALL CRAFT ADVISORIES FOR SAGINAW BAY AND THE NEARSHORE
WATERS FROM PORT AUSTIN DOWN TO PORT HURON. WINDS WILL RELAX ON
FRIDAY AS THE HIGH NUDGES INTO LOWER MI.
&&
.AVIATION...ISSUED 103 PM EDT FRI JUL 27 2012
//DISCUSSION...
SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AND INTENSITY
DURING THE COURSE OF THE AFTERNOON AS AN UPPER SHORT WAVE APPROACHES
FROM THE WEST AND INTERACTS WITH DAYTIME DESTABILIZATION. THE MORE
PERSISTENT FORCING AND THUS MORE PROLONGED PERIOD OF CONVECTION IS
EXPECTED TO OCCUR AROUND FNT AND POSSIBLY MBS. WHILE THE LOW CLOUDS
HAVE BEEN SLOWLY RECEDING OVER THE LAST COUPLE OF HOURS...THE
INCREASE IN SHOWERS SHOULD ALLOW A TRANSITION BACK TOWARD MVFR
CEILING HEIGHTS TOWARD EVENING. LOW LEVEL MOISTURE IS EXPECTED TO
CONTINUE TO FILTER INTO SE MI THIS EVENING AS LOW PRESSURE NOW OVER
SRN LAKE MI DROPS INTO THE OHIO VALLEY. THIS WILL LIKELY SUSTAIN
SOME SEMBLANCE OF LOW CLOUDS AND POSSIBLE FOG INTO THE OVERNIGHT.
DRIER AIR NOW NOTED NORTH OF LAKE HURON SHOULD HOWEVER ADVECT INTO
THE AREA FROM THE NORTH OVERNIGHT...LEADING TO STEADY IMPROVEMENT IN
CONDITIONS TOWARD DAYBREAK SATURDAY.
FOR DTW...BASED ON THE RATE OF DESTABILIZATION AND TIMING OF THE
APPROACHING FORCING...THERE IS A GOOD CHANCE OF THUNDERSTORMS
DEVELOPING AROUND 19 OR 20Z AND CONTINUING INTO 23 OR 00Z.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FT THIS AFTERNOON AND
TONIGHT.
* MEDIUM CONFIDENCE IN THUNDERSTORMS THIS AFTERNOON AND EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
HURON INCLUDING SAGINAW BAY...UNTIL 6 AM SATURDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...SC
LONG TERM....MM
MARINE.......SC
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GAYLORD MI
120 PM EDT FRI JUL 27 2012
.SYNOPSIS...
ISSUED AT 409 AM EDT FRI JUL 27 2012
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY...
BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
WILL THEN PROVIDE PLEASANT WEATHER FOR THE WEEKEND...BUT MORE
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN EARLY NEXT WORK
WEEK. NEAR SEASONAL TEMPERATURES ARE EXPECTED FOR THE NEXT SEVERAL
DAYS.
&&
.UPDATE...
ISSUED AT 120 PM EDT FRI JUL 27 2012
GOING FORECAST IN GOOD SHAPE THE REMAINDER OF THE AFTERNOON...WITH
RAIN HAVING A VERY HARD TIME MAKING MUCH NORTHWARD PROGRESS ON THE
FRINGES OF ELONGATING MID LEVEL DEFORMATION AXIS. HAVE ALREADY
SEEN SOME QUITE HEAVY TOTALS IN A FEW SPOTS (CADILLAC/FALMOUTH
COME TO MIND)...AND EFFICIENT WARM RAIN PROCESSES WILL CONTINUE IN
ANY SHOWERS/STORMS INTO LATE AFTERNOON. BEGINNING TO SEE A DIURNAL
COMPONENT TO ACTIVITY ACROSS SOUTHWEST COUNTIES WHERE SOME PEAKS
OF SUN ARRIVED EARLIER...AND SUSPECT THIS TREND WILL CONTINUE
ALONG THE M-55/WEST OF US-127 CORRIDOR THROUGH 22-23Z OR SO. ALL
THE WHILE...WILL CONTINUE TO SEE THINNING OF CLOUD COVER FOR
NORTHERN AREAS...WITH JUST SOME CU DEVELOPMENT. AS SUCH...EARLIER
TEMP FORECAST REMAINS INTACT...SHOWING LOW 70S AT BEST HIGHER
TERRAIN ON UPSLOPE FLOW TO MID/UPPER 70S FAR NORTH WITH BETTER SUN.
UPDATE ISSUED AT 1016 AM EDT FRI JUL 27 2012
GIST OF THE GOING FORECAST IS INTACT AS WE HEAD INTO THE
AFTERNOON...WITH ONLY MINOR TWEAKS MADE...PRIMARILY TO NORTHWARD
EXTENT OF EXPECTED PRECIP SHIELD. MODESTLY STRONG UPPER WAVE
CONTINUES TO PROGRESS THROUGH WISCONSIN...WITH A NOTABLE 700-500MB
AXIS OF DEFORMATION FORCING ACTING TO ELONGATE A BAND OF RAIN OVER
MUCH OF THE AREA SOUTH OF M-72. PRONOUNCED LOW LEVEL THETA-E AXIS
RUNNING ACROSS THIS AREA IS ALSO SERVING TO PROMOTE SOME WEAK
INSTABILITY BENEATH COOLING MID LEVELS...WITH UP TO 500 J/KG
MUCAPE PER SHORT TERM RAP FORECAST RAOBS. AS SUCH...NO SURPRISE WE
ARE SEEING OCCASIONAL THUNDER BREAK OUT AS WELL.
HEADING INTO THE LATE MORNING/AFTERNOON...SUSPECT PERIODS OF
SHOWERS AND STORMS WILL CROSS MUCH OF THE SOUTHERN HALF OF THE
CWA...ALL WHILE EXPANSIVE LOW LEVEL RIDGING AND ASSOCIATED DRYING
PUT A DEFINITELY NORTHERN EDGE TO THE PRECIP SHIELD. PER SHORT
TERM GUIDANCE AND STRONG SREF HINTS...WILL TRIM THE NORTHERN TIER
OF HIGHER POPS...WITH AREAS CLOSER TO LAKE HURON (NORTH OF M-32)
AND JUST ABOUT ALL OF EASTERN UPPER PROBABLY OUT OF THE MIX FOR
MUCH OF THE DAY. IN ADDITION TO EXPECTED AXIS OF DEFORMATION
FORCING...WILL LIKELY ALSO SEE SOME DIURNAL HELP TO THE PRECIP
WITHIN A QUITE MOIST AIRMASS...WITH SURFACE TEMPS INTO THE
LOWER/MIDDLE 70S PROMOTING MUCAPE VALUES UP TOWARD 700 J/KG. GIVEN
THE UPPER COLD POOL SKIRTING OVERHEAD AND A GOOD CHUNK OF
AVAILABLE INSTABILITY SITUATED ABOVE THE -12C ISOTHERM...SMALL
HAIL REMAINS A THREAT WITH ANY CONVECTION THAT DEVELOPS.
IN ADDITION...LOCALLY VERY HEAVY RAIN THREAT EXISTS WITHIN A
CORRIDOR OF 1.5+ INCH PWATS DOWN NEAR THE M-55 CORRIDOR WHERE
STEERING FLOW IS AN ANEMIC 5-10 KNOTS. MEANWHILE...FREEZING LEVELS
UP AROUND 10KFT AND A SATURATED ENVIRONMENT BELOW WILL SUPPORT VERY
EFFICIENT WARM RAIN PROCESSES...AND ENTIRELY POSSIBLE A FEW SPOTS
COULD PICK UP A LOCALIZED 2+ INCHES OF RAIN. CERTAINLY SOMETHING TO
WATCH. WILL ALSO HAVE TO WATCH VERY SMALL POTENTIAL FOR WATERSPOUTS
OVER LAKE MICHIGAN WITH UPPER COLD POOL SLIPPING OVERHEAD WHILE
WATER TEMPS ARE IN THE 22-24C RANGE. BEST THREAT WILL PROBABLY BE
OVER THE SOUTHERN HALF OF THE LAKE WHERE LOW LEVEL CONVERGENCE
BOUNDARY WILL RESIDE.
PER SATELLITE TRENDS...HAVE LOWERED GOING HIGHS A COUPLE OF
DEGREES INLAND WITH ONGOING UPSLOPE FLOW INTO THE HIGHER TERRAIN
LIKELY CAPPING THINGS AROUND 70 DEGREES...WITH DOWNSLOPE FLOW INTO
NORTHWEST LOWER KICKING THINGS TOWARD THE MID 70S. WARMEST SPOTS
WILL BE EASTERN UPPER WITH THINNING CLOUDS INTO THE AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 409 AM EDT FRI JUL 27 2012
EARLY MORNING SURFACE ANALYSIS SHOWS AN EAST-WEST ORIENTED TROUGH
AXIS LYING ACROSS SOUTHERN LOWER MICHIGAN/CENTRAL WISCONSIN.
COMPACT UPPER LOW WAS SPINNING SOUTHEAST INTO NORTHWEST
WISCONSIN...WITH A BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ARCING
AROUND THIS CIRCULATION FROM THE MICHIGAN/WISCONSIN BORDER SOUTHWARD
ACROSS EASTERN WISCONSIN (WATER VAPOR IMAGERY SHOWS UPWARD MOTION
FIELD AHEAD OF THIS LOW SPREADING ACROSS LAKE MICHIGAN).
MEANWHILE...A FEW SPOTTY RADAR RETURNS DEVELOPED NORTH OF THE
SURFACE TROUGH AXIS SOUTH OF THE M-55 CORRIDOR WHERE LOW LEVEL LAPSE
RATES WERE LIKELY A LITTLE STEEPER PER 00Z DTX SOUNDING.
UPPER LEVEL FEATURE WILL CONTINUE TO TRACK SOUTHEAST AND CROSS
SOUTHERN LOWER MICHIGAN DURING THE DAY. WEAK RIDGE OF HIGH PRESSURE
WILL BUILD INTO NORTHERN MICHIGAN IN THE WAKE OF THIS SYSTEM TONIGHT.
TRACK OF THE UPPER LEVEL LOW SUGGESTS HIGHEST PRECIPITATION CHANCES
TODAY WILL BE ACROSS THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
WILL BENEFIT THE MOST FROM THE SYNOPTIC COMPONENT WHICH SHOULD
ARRIVE THIS MORNING...PLUS STRONGEST DIURNAL COMPONENT WHERE LOW
LEVEL MOISTURE WILL BE MAXIMIZED AND MAY RESULT IN MLCAPE VALUES IN
THE 1000J/KG RANGE. PRECIPITATION CHANCES WILL BECOME MORE
SCATTERED TO THE NORTH WITH DRIER LOW LAYERS...AND LOOKING LIKE MOST
OF EASTERN UPPER WILL PROBABLY ESCAPE WITH LITTLE SIGNIFICANT
PRECIPITATION. THERMAL THROUGH ASSOCIATED WITH UPPER LEVEL WAVE
WILL LOWER FREEZING LEVELS...THUS STORMS WILL BE CAPABLE OF
PRODUCING HAIL. PLAN TO CARRY AN EXPLICIT MENTION OF SMALL HAIL
SOUTH OF A CVX-OSC LINE FROM LATE MORNING ONWARD. WARMEST HIGHS
TODAY WILL PROBABLY BE NORTH OF THE BRIDGE WHERE THERE WILL BE MORE
SUN ESPECIALLY LATER TODAY...IN GENERAL EXPECT HIGHS MAINLY IN THE
70S.
AS UPPER WAVE SLIPS INTO THE OHIO VALLEY THIS EVENING AND DRIER AIR
FILTERS INTO NORTHERN MICHIGAN IN ITS WAKE...THREAT FOR SHOWERS WILL
COME TO AN END ACROSS CENTRAL LOWER COUNTIES WITH SKIES CLEARING.
MAYBE A LITTLE PATCHY FOG ACROSS PARTS OF NORTHERN LOWER...BUT
SHOULD BE A SEASONABLY CHILLY NIGHT. COULD SEE A FEW SHELTERED
SPOTS DROPPING BELOW 50 EARLY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 409 AM EDT FRI JUL 27 2012
CURRENT UPPER LEVEL PATTERN SET TO CHANGE LITTLE FOR THE FORESEEABLE
FUTURE...FEATURING INTERMOUNTAIN WEST/HIGH PLAINS RIDGING BOOKENDED BY
EASTERN NOAM AND FAR EAST PACIFIC TROUGHINESS. AS A RESULT...
RECENTLY ESTABLISHED NORTHWEST FLAVOR TO MID LEVEL FLOW OVER THE
LAKES WILL REMAIN REMARKABLY PERSISTENT...KEEPING TEMPERATURES
LOCKED IN TO NEAR NORMAL LEVELS AND ALLOWING PERIODIC RAIN CHANCES
AS OCCASIONAL DISTURBANCES ROTATE THROUGH THE REGION. FORECAST
CONCERNS RELEGATED TO THE LATTER OF THESE TWO...FOCUSING ON SHOWER
AND STORM CHANCES NEXT WORK WEEK.
RESERVOIR OF DRY CANADIAN AIR SWEEPS SOUTH INTO THE NORTHERN LAKES
BEHIND TOMORROWS DEPARTING SYSTEM...SETTING UP A MAINLY QUIET...DRY
WEEKEND. OVERHEAD HIGH PRESSURE EXPECTED TO LEAD TO EXCELLENT LAKE
BREEZE DEVELOPMENT SATURDAY...AND COMBINED WITH LINGERING 850MB
THERMAL TROUGH...SHOULD SET UP A PRETTY DECENT INLAND CU FIELD BY
AFTERNOON. FORMIDABLE MID LEVEL CAP EXPECTED TO KEEP CLOUD HEIGHTS
IN CHECK AND PREVENT ANY SHOWER DEVELOPMENT. LATEST PROGS STARTING
TO THROW SOME CONCERN INTO INHERITED DRY SUNDAY... ESPECIALLY ACROSS
EASTERN UPPER. SUBTLE MID LEVEL WAVE AND BEGINNINGS OF MODEST RETURN
FLOW NOW SUPPORTING SOME EASTERN UPPER SHOWERS BY AFTERNOON.
GUIDANCE IS NOTORIOUS FOR BRINGING IN MOISTURE TOO QUICKLY...
ESPECIALLY WITH AN ANTECEDENT RELATIVELY DRY AIR MASS. WILL REFRAIN
FROM INTRODUCING ANOTHER PERIOD OF LOW END SHOWER POTENTIAL (SEE
BELOW)...WAITING FOR MORE CONSISTENCY BEFORE DOING SO. NEAR SEASONAL
HIGH TEMPERATURES EXPECTED BOTH AFTERNOONS...WITH READINGS IN THE
UPPER 70S AND LOWER 80S.
"POTENTIALLY" SOMEWHAT MORE ACTIVE PERIOD OF WEATHER RETURNS NEXT
WORK WEEK...WITH ABOVE OUTLINED FLOW AT LEAST OPENING UP THE
OPPORTUNITY FOR A FEW DISTURBANCES TO ROTATE THROUGH THE REGION.
NOTHING EARTH SHATTERING PER TRENDS...WITH GUIDANCE SUGGESTING LOW
AMPLITUDE WAVES AND DEEPEST CORE OF MOISTURE TO REMAIN WELL TO OUR
SOUTHWEST. AS EXPECTED WITH THIS FLOW REGIME...EXACT TIMING REMAINS
PROBLEMATIC AT BEST...WITH THE ECMWF LAGGING BEHIND BOTH THE GFS AND
GEM BY SEVERAL HOURS WITH LEAD WAVE LATE SUNDAY NIGHT INTO MONDAY.
SIMPLY NOT PRUDENT AT THIS HOUR TO PICK ONE OVER THE OTHER...AND
WILL RIDE WITH LATE SUNDAY NIGHT INTO MONDAY LOW END RAIN CHANCES.
SAME GOES FOR MONDAY NIGHT AND TUESDAY AS ADDITIONAL SUPPORT
PINWHEELS OVER THE REGION. UNFORTUNATELY...BECAUSE OF SAID TIMING
CONCERNS...SIMPLY NO WAY TO SIDESTEP INHERITED MULTI-PERIOD RAIN
CHANCES...ALTHOUGH IN ALL LIKELIHOOD...MUCH OF THE TIME OUTLINED
ABOVE WILL REMAIN DRY. OF COURSE...TEMPERATURES DIRECTLY TIED TO
CONVECTIVE TRENDS...BUT OFF THE DECK THERMAL TRENDS SUGGEST HIGHS
BOTH MONDAY AND TUESDAY REMAINING IN THE UPPER 70S AND LOWER 80S.
PATTERN LOOKS TO SIMPLY REPEAT ITSELF LATER IN THE WEEK...WITH
TRENDS SUPPORTING A DRY MID WEEK PERIOD FOLLOWED BY ADDITIONAL RAIN
CHANCES THURSDAY INTO FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 120 PM EDT FRI JUL 27 2012
TALE OF TWO DIFFERENT WEATHER REGIMES ACROSS THE TAF SITES AS AN
UPPER LOW CONTINUES TO TRAVERSE THE REGION. WORST CONDITIONS BY
FAR WILL COME AT MBL AND TVC WITH MVFR TO PERIODIC IFR CONDITIONS
WITH OCCASIONAL ROUNDS OF SHOWERS AND PERHAPS A THUNDERSTORM.
FARTHER NORTH FOR PLN/APN...SLOW IMPROVEMENT IS EXPECTED AS LOWER
CLOUDS LIFT INTO A VFR DECK THROUGH THE AFTERNOON. CONDITIONS AT
ALL SITES WILL IMPROVE OVERNIGHT AS THE UPPER LOW DEPARTS AND HIGH
PRESSURE BEGINS TO BUILD INTO THE AREA. INFLUX OF DRIER AIR SHOULD
PREVENT ANY WIDESPREAD FOG FROM DEVELOPING AT APN/PLN...WITH A
BETTER CHANCE AT TVC AND ESPECIALLY MBL WHERE RAINS HAVE FALLEN OR
WILL FALL TODAY. WINDS FROM THE EAST AT UP TO 10 KNOTS WILL
DIMINISH OVERNIGHT...COMING FROM THE NORTH AT UP TO 8 KNOTS
SATURDAY WITH SOME AFTERNOON CUMULUS LIKELY TO DEVELOP.
&&
.MARINE...
ISSUED AT 409 AM EDT FRI JUL 27 2012
EAST/NORTHEAST WINDS EXPECTED TODAY ACROSS THE UPPER LAKES...WITH
THE FORECAST AREA SANDWICHED BETWEEN A TROUGH OF LOW PRESSURE
DROPPING SOUTH TOWARD THE OHIO VALLEY AND A WEAK RIDGE OF HIGH
PRESSURE BUILDING IN FROM THE NORTH. WINDS WILL BACK MORE TOWARD
THE NORTH TONIGHT BUT GRADIENT WILL BE WEAKENING AS AFOREMENTIONED
RIDGE BUILDS IN.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MSB
SHORT TERM...JPB
LONG TERM...MSB
AVIATION...LAWRENCE
MARINE...JPB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
103 PM EDT FRI JUL 27 2012
.AVIATION...
//DISCUSSION...
SHOWERS AND THUNDERSTORMS WILL EXPAND IN COVERAGE AND INTENSITY
DURING THE COURSE OF THE AFTERNOON AS AN UPPER SHORT WAVE APPROACHES
FROM THE WEST AND INTERACTS WITH DAYTIME DESTABILIZATION. THE MORE
PERSISTENT FORCING AND THUS MORE PROLONGED PERIOD OF CONVECTION IS
EXPECTED TO OCCUR AROUND FNT AND POSSIBLY MBS. WHILE THE LOW CLOUDS
HAVE BEEN SLOWLY RECEDING OVER THE LAST COUPLE OF HOURS...THE
INCREASE IN SHOWERS SHOULD ALLOW A TRANSITION BACK TOWARD MVFR
CEILING HEIGHTS TOWARD EVENING. LOW LEVEL MOISTURE IS EXPECTED TO
CONTINUE TO FILTER INTO SE MI THIS EVENING AS LOW PRESSURE NOW OVER
SRN LAKE MI DROPS INTO THE OHIO VALLEY. THIS WILL LIKELY SUSTAIN
SOME SEMBLANCE OF LOW CLOUDS AND POSSIBLE FOG INTO THE OVERNIGHT.
DRIER AIR NOW NOTED NORTH OF LAKE HURON SHOULD HOWEVER ADVECT INTO
THE AREA FROM THE NORTH OVERNIGHT...LEADING TO STEADY IMPROVEMENT IN
CONDITIONS TOWARD DAYBREAK SATURDAY.
FOR DTW...BASED ON THE RATE OF DESTABILIZATION AND TIMING OF THE
APPROACHING FORCING...THERE IS A GOOD CHANCE OF THUNDERSTORMS
DEVELOPING AROUND 19 OR 20Z AND CONTINUING INTO 23 OR 00Z.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILINGS BELOW 5000 FT THIS AFTERNOON AND
TONIGHT.
* MEDIUM CONFIDENCE IN THUNDERSTORMS THIS AFTERNOON AND EVENING.
&&
.PREV DISCUSSION...ISSUED 1041 AM EDT FRI JUL 27 2012
UPDATE...
THE REGIONAL WATER VAPOR LOOP SHOWS A FAIRLY HEALTHY MID LEVEL
WAVE OVER ERN WISCONSIN. ALTHOUGH THIS WAVE IS EXPECTED TO DAMPEN
AS IT TRACKS ACROSS LOWER MI LATER TODAY...THERE WILL STILL BE
ADEQUATE FORCING FOR LARGE SCALE ASCENT DURING PEAK DAYTIME
HEATING. RECENT TRENDS IN THE VISIBLE LOOP ARE SHOWING SOME OF THE
LOW STRATUS STARTING TO TRANSITION TO A BROKEN CU FIELD AS DAYTIME
INSOLATION IS NOW WARMING THE BOUNDARY LAYER. THIS WILL SUPPORT
INCREASING CONVECTIVE CLOUD DEPTHS WHICH WILL LEAD TO OCCASIONAL
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. REGIONAL RADAR IMAGERY
IS SHOWING AN AREA OF MORE PERSISTENT RAIN AND EMBEDDED
THUNDERSTORMS EXTENDING FROM CNTL LOWER MI TO NW LOWER MI...WITHIN
A REGION OF WEAK MID LEVEL DEFORMATION...WHICH WILL TARGET THE
SAGINAW VALLEY AND THUMB THIS AFTERNOON AND EVENING. DEEP LAYER
MOISTURE WILL ALSO BE BETTER TO THE NORTH. GIVEN THE SLOW MOVEMENT
OF THE UPPER WAVE...SOME PROLONGED PERIODS OF MODERATE TO HEAVY
RAINFALL LOOK POSSIBLE ACROSS THE NORTHERN PORTIONS OF THE
FORECAST AREA.
DRY AIR IN THE MID LEVELS FARTHER SOUTH SUGGEST SOME AFTERNOON
STORMS MAY SUPPORT SOME SMALL HAIL. THERE HAS BEEN MORE PERSISTENT
SUNSHINE ACROSS LENAWEE AND MONROE COUNTIES THIS MORNING...WHICH
MAY ALLOW SOME BETTER INSTABILITY TO DEVELOP BY AFTERNOON /SB CAPE
UP TO 2000 J/KG/. THIS REGION WILL ALSO LIE ALONG THE NORTHERN
EDGE OF A 40KT MID LEVEL JET...SUPPORTIVE OF A SLIGHT CHANCE OF
STRONG TO POSSIBLE SEVERE STORMS LATER TODAY.
THE UPDATE WILL BE ISSUED MAINLY TO NUDGE POPS UPWARD.
PREV DISCUSSION...ISSUED 339 AM EDT FRI JUL 27 2012
SHORT TERM...TODAY AND TONIGHT
ACTIVE BUT WEAK SURFACE PATTERN IN PLACE ACROSS THE GREAT LAKES
THROUGH FRIDAY. ONE COLD FRONT HAS PASSED THROUGH THE REGION LOCATED
JUST TO OUR SOUTH ACROSS THE OHIO VALLEY AS OF 06Z. MID/UPPER LEVEL
TROUGH AXIS IS CURRENTLY OVER MN/WI AND IS WORKING ITS WAY TOWARDS
SE MI. A COMPACT SHORTWAVE WITHIN TROUGH WILL PASS THROUGH SOUTHERN
MI DURING THE DAY/EVENING TODAY. MODELS ARE IN GOOD AGREEMENT THAT
THIS WAVE WILL WEAKEN AS IT APPROACHES AND HAS ALREADY BECOME AN
OPEN WAVE. MODELS DO NOT AGREE WITH THE TRACK OF THE ASSOCIATED SFC
LOW. THE NAM IS ALREADY TOO FAR SOUTH WITH IT HENCE WILL BE
DISREGARDED. CONSENSUS WITH THE OTHER MODELS BRINGS THE SFC LOW
THROUGH SOUTHERN LOWER MI FRIDAY AFTERNOON. MODEL SOUNDINGS SHOW A
FAIRLY NARROW CAPE PROFILES WITH A SMALL CAP BETWEEN 850-900MB WHICH
SHOULD BE OVERCOME IN THE AFTERNOON. WITH RELATIVELY HIGH SFC
DEWPOINTS TONIGHT AND COOLING MID LEVELS TEMPS...WE WILL KEEP DECENT
LAPSE RATES TO GO WITH THE CAPE VALUES AROUND 500 J/KG. AS FOR
FORCING MECHANISMS...WE ARE PRIMARILY DEALING WITH THE MID LEVEL
COLD POOL AND WEAKENING SHORTWAVE. THERE IS A JET MAX THAT WILL
ROUND THE RIDGE CENTERED OVER THE WESTERN PLAINS...BUT SHOULD PASS
TO OUR SW THROUGH THE MID MISSISSIPPI VALLEY. AS FOR POSSIBLE
FRONTAL FORCING...WITH THE LOW PASSING ACROSS SOUTHERN MI THE COLD
FRONT SHOULD FOCUS CONVECTION ACROSS THE OHIO VALLEY AND NOT AFFECT
SE MI. LOOKS LIKE THE BIGGEST AIDE WILL BE THE TIMING OF THE
SHORTWAVE PASSAGE...DURING PEAK DIURNAL HEATING. LOOKING AT CURRENT
REGIONAL RADAR MOSAICS...THE HRRR HAS THE SYSTEM PEGGED PRETTY WELL
SO FAR AND THE MODEL OUTPUT MOVING FORWARD SEEMS VERY REASONABLE.
LOOK FOR SCATTERED SHOWERS AND THUNDERSTORMS TO MOVE INTO THE
WESTERN COUNTIES BY MORNING WITH MORE WIDESPREAD ACTIVITY DEVELOPING
AS DIURNAL HEATING BECOMES MAXIMIZED. THOUGH THUNDERSTORMS MAY
DEVELOP...NOT EXPECTING ANYTHING SEVERE AS THE BETTER FORCING AND
INSTABILITY WILL BE TO OUR SOUTH CLOSER TO THE SFC COLD FRONT AND
THE BETTER HEIGHT FALLS.
LONG TERM...SATURDAY THROUGH THURSDAY
HIGH PRESSURE WILL BUILD INTO THE AREA IN THE WAKE OF THE SHORTWAVE
THAT WILL PASS THROUGH THE AREA FRIDAY. THIS WILL BRING A PERIOD OF
DRY WEATHER OVER THE WEEKEND. RATHER PLEASANT CONDITIONS CAN ALSO BE
EXPECTED AS TEMPERATURES TOP OUT IN THE LOWER/MID 80S FOR THE MOST
PART WITH RELATIVELY LOW HUMIDITY LEVELS. WITH HIGH PRESSURE IN
PLACE...SKIES WILL REMAIN MOSTLY CLEAR BOTH SATURDAY/SUNDAY.
FROM THIS WEEKEND INTO EARLY NEXT WEEK...STRONG LOW PRESSURE FROM
HUDSON BAY NORTH WILL KEEP A MEAN UPPER TROUGH ANCHORED OVER THE
REGION THROUGH MUCH OF NEXT WEEK. A SERIES OF WEAK SHORTWAVES WILL
TRACK THROUGH THE GREAT LAKES FROM MONDAY ON THROUGH THE REMAINDER
OF THE FORECAST PERIOD. ALTHOUGH MOISTURE WILL BE SOMEWHAT SCARCE
WITHIN THIS NORTHWEST UPPER LEVEL FLOW REGIME...THERE WILL BE ENOUGH
INSTABILITY TO GENERATE SCATTERED SHOWERS AND/OR THUNDERSTORMS WITH
THESE WAVES NEXT WEEK. DO NOT PLAN ON ADJUSTING FORECAST TOO MUCH
GIVEN UNCERTAINTY IN TIMING ANY OF THESE WAVES THIS LATE IN THE
FORECAST PERIOD. SUFFICE IT TO SAY THAT THERE WILL BE PERIODIC
CHANCES OF SCATTERED CONVECTION FROM MONDAY THROUGH THURSDAY AS THE
OVERALL PATTERN CHANGES VERY LITTLE.
THE TEMPERATURES WILL REMAIN SEASONABLY WARM WITH 80S COMMON FOR
DAYTIME HIGHS AND 60S FOR NIGHTTIME LOWS...WITH ONLY MINOR DAY TO
DAY FLUCTUATIONS DEPENDENT ON THE TIMING OF THE VARIOUS SHORTWAVES.
MARINE...
WEAK LOW PRESSURE SYSTEM WILL TRACK THROUGH THE CENTRAL GREAT LAKES
FRIDAY. THIS WILL KEEP SHOWERS AND THUNDERSTORMS IN THE AREA THROUGH
FRIDAY EVENING. THE TRACK OF THE LOW WILL KEEP NORTHEASTERLY FLOW
OVER THE EASTERN LAKES THROUGH THE WEEKEND. NE WINDS WILL PEAK ON
SATURDAY ON THE BACKSIDE OF THE LOW WHICH WILL BUILD WAVE HEIGHTS
ALONG THE LAKE HURON SHORELINE. AT THIS TIME...WAVES LOOK LIKE THEY
WILL APPROACH 3-4 FEET ON THE GENEROUS SIDE. HIGH PRESSURE WILL
BUILD BACK INTO THE AREA FOR THE REST OF THE WEEKEND BRINGING LIGHT
WINDS AND DECREASING WAVES TO THE LAKES.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...DRK
LONG TERM....DG
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BISMARCK ND
347 PM CDT FRI JUL 27 2012
.SHORT TERM...NOW THROUGH SATURDAY NIGHT...
MIDDLE LEVEL SHORTWAVES EMBEDDED WITHIN THE CYCLONIC FLOW OVER
NORTHWESTERN CONUS WILL OCCASIONALLY PHASE WITH MIDDLE LEVEL
SHORTWAVES REVOLVING AROUND THE DOMINANT SUBTROPICAL HIGH OVER
CENTRAL CONUS AS THEY PASS THROUGH THE NORTHERN HIGH PLAINS. THIS
PHASING SHOULD INTRODUCE BROAD SCALE UPWARD VERTICAL MOTION
SUFFICIENT TO ERODE CAPPING ASSOCIATED WITH THE SUBTROPICAL HIGH
SUBSIDENCE.
THE MAIN FORECAST PROBLEM TODAY IS DECIDING WHEN THE BEST PHASING
WILL OCCUR AND INTRODUCING HIGHER PRECIPITATION CHANCES AT THOSE
TIMES. THE PRECIPITATION CHANCES REPRESENT A BLEND OF THE 15 UTC
SREF MEAN AND 12 UTC ECMWF/GFS/GEM GLOBAL AND RECENT HRRR RUNS.
ABOVE AVERAGE TEMPERATURES SHOULD RETURN INTO THE FORECAST THIS
WEEKEND...AND THERE IS NO INDICATION THAT THE CENTRAL U.S. RIDGE
WILL MOVE OR WEAKEN. THUS...EXPECT THE ACTIVE PATTERN TO CONTINUE
AS IMPULSES TRAVEL THROUGH THE NORTHERN PLAINS.
.LONG TERM...SUNDAY THROUGH FRIDAY...
WESTERN ROCKIES AND HIGH PLAINS RIDGE REMAINS PERSISTENT THROUGH THE
EXTENDED PERIODS WITH PERIODIC SHORTWAVES TOPPING THE RIDGE AND
BRINGING EPISODES OF THUNDERSTORMS TO THE FORECAST AREA. THE FIRST
SYSTEM IN THE EXTENDED WILL MOVE ACROSS THE NORTHERN PLAINS SATURDAY
NIGHT/SUNDAY AT THE BEGINNING OF THE PERIOD WITH A WEAK SURFACE
TROUGH TRAVERSING THE STATE. HAVE RAISED CHANCES DAYTIME SUNDAY WITH
A BIT MORE CONFIDENCE ON TIMING. THE NEXT SYSTEM APPROACHES ON
TUESDAY INTO WEDNESDAY/THURSDAY...WITH A MORE SIGNIFICANT
LOW/SHORTWAVE DEPICTED MOVING THROUGH THE FORECAST AREA ON FRIDAY.
TIMING OF SHORT WAVES WILL BE DIFFICULT AND LOW POPS CHANCES
GENERALLY IN MUCH OF THE EXTENDED PERIODS UNTIL THE END OF NEXT
WEEK.
TEMPERATURES SHOULD BE SLIGHTLY ABOVE AVERAGE WITH HIGHS MAINLY IN
THE UPPER 80S TO LOWER 90S AND LOWS IN THE 60S.
&&
.AVIATION...
VFR CONDITIONS TO CONTINUE THIS AFTERNOON ALL TAF SITES.
THE FIRST IN A SERIES OF LOWS IS FORECAST TO MOVE EASTWARD FROM
CENTRAL MONTANA/WYOMING AND REACH SOUTHWESTERN NORTH DAKOTA AROUND
00Z...AND SPREAD NORTH AND EAST ACROSS CENTRAL NORTH DAKOTA
AROUND/AFTER 06Z. ADDED MENTION OF VCTS TO KDIK AT 03Z AND AT KISN
AT 06Z...BUT LEFT MENTION OUT OF KBIS/KMOT DUE TO SCATTERED/ISOLATED
NATURE OF CONVECTION BY THE TIME THE IMPULSE WOULD REACH CENTRAL
NORTH DAKOTA. LATER TAF ISSUANCE MAY REFINE COVERAGE AND TIMING OF
CONVECTION FOR KBIS/KMOT/KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION...JV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
245 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND
EVENING. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE NORTHWEST
THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPR LVL S/WV LOCATED OVER THE WRN GREAT LAKES THIS MORNING WILL
PIVOT SE ACRS THE REGION LATE THIS AFTN AND OVERNIGHT. AN AREA OF
WEAK LOW PRESSURE AND A SFC COLD FRONT WILL ACCOMPANY THIS FEATURE
AS THEY SLOWLY MOVE SOUTHEAST THROUGH THE REGION OVERNIGHT. THE
COMBINATION OF THESE FEATURES WILL INTERACT WITH A MOIST AND
UNSTABLE AIRMASS THIS AFTERNOON AND EVENING...RESULTING IN
CONVECTIVE DEVELOPMENT FROM EARLY AFTERNOON INTO THE EVENING
HOURS. LATEST HRRR AND NAM SUGGEST THAT CONVECTION WILL GET GOING
ACRS NRN AND CENTRAL INDIANA EARLY THIS AFTERNOON...AND SHOULD
PROPAGATE SE THROUGH OUR AREA THIS AFTERNOON INTO THIS EVENING.
WITH BULK SHEAR IN THE 25 TO 35 KNOT RANGE...STORMS SHOULD EXHIBIT
SOME ORGANIZATION WITH MULTICELLS PERHAPS MERGING INTO LINEAR
BOWING SEGMENTS. IN ADDITION...WITH THE SFC LOW APPROACHING OUR NW
CWFA...THERE WILL BE SOME DIRECTIONAL SHEAR THAT MAY CAUSE A FEW
STORMS TO ROTATE. AS A RESULT OF ALL THESE FACTORS...HAVE GONE
WITH LIKELY POPS THIS AFTERNOON AND HAVE PLACED SEVERE WORDING IN
THE FORECAST. MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS
WITH SEVERE HAIL THE SECONDARY THREAT. AN ISOLATED TORNADO CAN NOT
BE RULED OUT...ESPECIALLY ACRS THE NWRN CWFA. ALTHOUGH STORMS WILL
HAVE SOME MOTION 20 TO 30 MPH AND RAINFALL RATES WILL NOT BE AS
HIGH AS YESTERDAY...OUR SE CWFA RECEIVED SUBSTANTIAL RAINFALL
AMOUNTS IN THE 3 TO 5 INCHES RAIN OVER THE LAST 24 HOURS. THIS HAS
RESULTED IN MOIST IF NOT NEARLY SATURATED SOILS IN THESE LOCALES.
1 HOUR FFG SUBSEQUENTLY ARE RANGING ANY WHERE BETWEEN A HALF INCH
TO AN INCH. GIVEN THIS SETUP...ANY STORMS THAT FORM TODAY...AND IF
THEY MOVE OVER THE SAME AREAS IN THE SE CWFA...THIS WILL LIKELY
RESULT IN AN INCREASED FLOOD THREAT...WITH THE POTENTIAL FOR FLASH
FLOODING. HAVE ISSUES A FLASH FLOOD WATCH FOR THE SE CWFA IN
EFFECT FROM 18Z THIS AFTN TO 08Z EARLY SATURDAY MORNING.
AS FOR TEMPERATURES AND DEWPOINTS...IT WILL BE ANOTHER VERY WARM
TO LOCALLY HOT DAY WITH HIGHS GENERALLY IN THE UPPER 80S TO THE
LOWER 90S AND DEWPOINTS IN THE MID 60S TO AROUND 70. THIS SHOULD
KEEP HEAT INDICES IN THE MID TO UPPER 90S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING INTO THE
EVENING ACROSS THE REGION PARTICULARLY IN THE EAST BEFORE MOVING
OFF AS THE COLD FRONT CONTINUES TO PROGRESS EASTWARD. INCREASED
LOW LEVEL MOISTURE AND WEAK COLD ADVECTION BEHIND THE FRONT SHOULD
RESULT IN THE DEVELOPMENT OF LOW CLOUDS THAT WILL LAST WELL INTO
SATURDAY MORNING. COULD STILL SEE A FEW SHOWERS AND THUNDERSTORMS
DEVELOP ON SATURDAY PRIMARILY IN THE NORTHERN COUNTIES WITH
HEATING AND A WEAK DISTURBANCE DROPPING INTO THE UPPER TROUGH. AS
HIGH PRESSURE BUILDS OVER THE AREA SATURDAY NIGHT AND SUNDAY...
CONDITIONS WILL BE QUIESCENT.
FOLLOWING RECENT TRENDS HAVE PATTERNED TEMPERATURE FORECAST NEAR
OR SLIGHTLY ABOVE WARMER MOS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE WEEK. THIS PATTERN
IS CONDUCIVE TO CONVECTIVE DEVELOPMENT AS DISTURBANCES DROP
SOUTHEAST. HOWEVER THESE DISTURBANCES ARE OFTEN DIFFICULT TO TRACK
AND TIME. AT THIS POINT HAVE INCLUDED LOW CHANCE POPS MAINLY
DURING THE DAYTIME PERIODS. TEMPERATURES WILL REMAIN ABOVE NORMAL.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL DISTURBANCE OVER THE WESTERN GREAT LAKES THIS
AFTERNOON WILL PIVOT SE ACRS THE REMAINDER OF THE GREAT LAKES TONIGHT
AND SATURDAY. THIS WILL SLOWLY PUSH A WEAK AREA OF LOW PRESSURE
AND ASSOCIATED COLD FRONT SOUTHEAST THROUGH THE REGION. THE
APPROACH OF THIS DISTURBANCE AND PREFRONTAL CONVERGENCE AHEAD OF
THE FRONT WILL TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS ACRS
THE AREA EARLY THIS AFTN. MODELS SUGGEST THAT MULTICELLULAR
THUNDERSTORMS COULD CONGEAL INTO BOWING SEGMENTS WITH POSSIBLE TWO
ROUND OF CONVECTION MOVING OVER THE REGION. AS SUCH...BELIEVE
THUNDERSTORM CHANCES ARE HIGH ENOUGH TO WARRANT AT ALL TAF SITES.
HOWEVER...EXACT TIMING IS STILL DIFFICULT AT THIS POINT AND HAVE
THUS GONE WITH A PREDOMINANT VCTS WITH TEMPO MVFR AND THUNDER.
WILL AMENDMENT TAFS ACCORDINGLY FOR WIND AND/OR HAIL PER RADAR
OBSERVATIONS.
FOR THE OVERNIGHT HOURS...CONVECTION SHOULD PUSH TO THE
EAST/SOUTHEAST THIS EVENING. STILL CAN NOT RULE OUT A SHOWER OR
STORM OVERNIGHT WITH THE DISTURBANCE STILL IN THE REGION...BUT
CHANCES ARE LOW ENOUGH TO NOT MENTION ATTM. OF GREATER CONCERN
WILL BE LOW LEVEL MOISTURE ADVECTING SOUTH AROUND WEAK LOW
PRESSURE/COLD FRONT. THIS MOISTURE...COMBINED WITH WEAK COLD AIR
ADVECTION...HAS THE POTENTIAL TO REALIZE ITSELF AS A STRATUS DECK
LATE TONIGHT INTO SATURDAY MORNING. SOME MVFR/IFR VSBYS WILL BE
POSSIBLE AS WELL AND HOW LOW THESE BECOME WILL DEPEND ON HOW FAST
MID LVL CLOUDS EXIT THE REGION BEFORE LOW STRATUS FORMS. HAVE GONE
WITH IFR CIGS AND MVFR/IFR VSBYS ATTM.
ON SATURDAY...LOW LEVEL MOISTURE/STRATUS SHOULD LIFT INTO VFR
CUMULUS AND/OR MODERATE CUMULUS BY SATURDAY AFTERNOON WHILE VSBYS
WILL IMPROVE TO VFR AS WELL. CAN NOT RULE OUT A POP UP SHOWER OR
STORM ACRS THE ERN TAF SITES...BUT THEN AGAIN...IT IS TOO LOW TO
BE CONCERNED ABOUT ATTM.
UNDER A NW FLOW ALOFT...SURFACE HIGH PRESSURE IS FORECAST TO BUILD
SOUTHEAST INTO THE GREAT LAKES AND OHIO VALLEY SATURDAY NIGHT INTO
SUNDAY.
.OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY AND TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ079>082-088.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ098>100.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...
LONG TERM...
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
151 PM EDT FRI JUL 27 2012
.SYNOPSIS...
A WEAK COOL FRONT WILL SLOWLY SETTLE SOUTHEAST ACROSS THE REGION
THROUGH THE WEEKEND BEFORE GRADUALLY DISSIPATING. ANOTHER WEAK FRONT
IS EXPECTED TO APPROACH THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM...CONVECTION BEGINNING TO FIRE AS ANTICIPATED. LOOKS
LIKE CURRENT POP GRIDS IN GOOD SHAPE AS WELL AS TEMP TRENDS. SO NO
SIGNIFICANT ADJUSTMENTS NECESARY EXCEPT FOR SOME MINOR TWEAKS.
PREVIOUS DISCUSSION:
AS OF 1030 AM...MOST COMPLICATED PART OF THE FORECAST AS USUAL DURING THE
SUMMER IS THE CONVECTIVE COMPONENT. THERE WILL CERTAINLY BE SOME
DEEP CONVECTION THIS AFTERNOON...BUT THERE ARE COVERAGE AND
INTENSITY QUESTIONS. THE MESO MODELS LIKE THE HRRR AND RAP GEN UP
CONVECTION EARLY THIS AFTERNOON IN THE LEE OF THE MOUNTAINS IN
WESTERN NC APPARENTLY RESPONDING TO WEAK VORT MX MOVING MOVING
THROUGH UPSTATE SC. SOME MID LEVEL CLOUDS ARE SHOWING UP THERE SO
THIS BASIC IDEA LOOKS REASONABLE. THE HRRR MOVES THIS INITIAL
CLUSTER SE WITH LITTLE DEVELOPMENT IN ITS WAKE. THE 12Z NAM HAS A
SIMILAR IDEA THOUGH MORE COVERAGE. I AM INCLINED TO BELIEVE THERE
WILL BE MORE COVERAGE THAN WHAT THE HRRR IMPLIES...ACTUALLY MORE
ALONG THE LINES OF THE NAM AND OUR LOCAL WRF. HENCE...HAVE TRENDED
THE POP FIELD IN THE MORE GENEROUS DIRECTION FOR TODAY. TEMP TRENDS LOOK
BANG ON FOR THE MOST PART SO ONLY MINOR CHANGES. CURRENT HEAT
ADVISORY ACROSS THE SOUTHERN PIEDMONT LOOKS WELL PLACED AND WILL
CONTINUE THAT.
IN REGARD TO THE SEVERE THREAT FOR TODAY...THE MID LEVEL FLOW WILL
BE MUCH BETTER TO THE N OF OUR AREA THIS AFTN...BUT 500 MB WINDS
COULD APPROACH 25 KT ACROSS THE FAR NRN TIER WHICH WOULD SUPPORT A
MULTICELL MODE THERE. FARTHER TO THE SOUTH...THE STRONGLY HEATED
BOUNDARY LAYER WILL PRODUCE CAPES INCREASING TO 1500-2000J WHICH
WILL SUPPORT A PULSE SEVERE THREAT PRIMARLY FOR WET MICROBURSTS.
SPC HAS PLACED THE AREA IN A SLIGHT RISK AREA.
EXPECT THAT CONVECTION SHOULD WANE QUICKLY THIS EVENING THANKS TO
WEAK NVA BEHIND DEPARTING VORT MAX. QUICK PEAK AT 12Z NAM SUPPORTS
THIS SCENARIO. WILL MAKE SOME ADJUSTMENTS TO TONIGHT`S POP GRIDS
MASED ON 12Z NAM. ANOTHER WARM AND MUGGY NIGHT IS IN STORE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...THE MODELS APPEAR TO AGREE IN SHUNTING THE
DEEPER MOISTURE TOWARD THE COASTAL PLAIN BY SATURDAY AFTERNOON.
HOWEVER...THERE IS SLIGHT DISAGREEMENT ON THE POSITION OF THE
SURFACE BOUNDARY...AND A MAJOR DISCREPANCY BETWEEN THE GFS AND THE
NAM ON THE DISTRIBUTION OF INSTABILITY ACROSS THE REGION SAT
AFTERNOON. THE GFS HAS A VERY SHARP CAPE GRADIENT...WITH VERY LITTLE
IN THE WAY OF INSTABILITY WEST OF THE FRONTAL ZONE (I.E. VERY LITTLE
INSTABILITY IN OUR AREA). MEANWHILE...THE NAM DEPICTS A MORE DIFFUSE
SURFACE BOUNDARY...WITH PLENTY OF LOW-LEVEL MOISTURE LINGERING TO
SUPPORT HIGH CAPE VALUES ACROSS THE CWA. CONSIDERING THE TIME OF
YEAR...AND EXAMINING CURRENT OBS WEST OF THE FRONTAL BOUNDARY...I
HAVE A DIFFICULT TIME BUYING IN TO THE GFS INSTABILITY PICTURE. THIS
HAS MAJOR FORECAST IMPLICATIONS...AS BOTH MODELS FEATURE A RATHER
POTENT SHORT WAVE TROUGH TRAVERSING THE AREA DURING THE AFTERNOON.
WITH THE LONG WAVE TROUGH AXIS OVERHEAD...THERE SHOULD BE A DECENT
AMOUNT OF DEEP LAYER SHEAR (25-30 KT)...AND THE SHORT WAVE COULD
PROMOTE DEVELOPMENT OF ORGANIZED CONVECTION DURING PEAK HEATING. IN
FACT...THE NAM IS DOING JUST THAT. IN LIGHT OF THE VERY DRY
MID-LEVELS ALONG WITH MODERATE DEEP LAYER SHEAR...CONVECTION MAY
TEND A LITTLE TOWARD DISCRETE CELLS...SO IM NOT PREPARED TO MAKE
MAJOR INCREASES IN POPS...BUT THEY HAVE BEEN INCREASED TO 30-40
PERCENT FROM THE BLUE RIDGE EAST. FORECAST SOUNDINGS DEPICT VERY
HIGH VALUES OF DCAPE...SO DAMAGING MICROBURSTS WOULD BE OF PRIMARY
CONCERN.
ANY CONVECTION WILL SWEEP EAST WITH THE SHORT WAVE SAT EVENING...
LEAVING MOSTLY DRY CONDITIONS THROUGH AT LEAST SUNDAY MORNING. THE
TROUGH AXIS REMAINS OVERHEAD SUNDAY...BUT RISING HEIGHTS IN THE WAKE
OF THE SHORT WAVE WILL RESULT IN GRADUALLY WEAKENING FLOW. IT
APPEARS THE BEST INSTABILITY WILL BE EAST OF THE AREA...BUT THERE
WILL BE MORE THAN ADEQUATE CAPE VALUES BENEATH DIFFLUENT FLOW ALOFT
TO SUPPORT ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON.
THE MODELS SUGGEST CONVECTION WILL LINGER INTO SUNDAY NIGHT...AS
MOISTURE DEEPENS IN RESPONSE TO THE APPROACH OF ANOTHER SHORT WAVE
TROUGH...SO AT LEAST SLIGHT CHANCES WILL EXIST ACROSS MUCH OF THE
AREA THROUGH THE OVERNIGHT. TEMPS WILL COOL SLIGHTLY BENEATH THE
UPPER TROUGH AXIS...BUT WILL STILL REMAIN AROUND NORMAL THROUGH THE
PERIOD.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 1215 PM FRIDAY...MEDIUM RANGE MODELS ARE CONTINUING TO
ADVERTISE THE POTENTIAL FOR ENERGY ROTATING INTO THE REGION ON
TUESDAY WITHIN THE BASE OF LINGERING EASTERN CONUS L/WV TROUGH.
GIVEN THE UNSETTLED LOOK OF THE LARGE SCALE PATTERN...SOLID CHANCE
POP WILL BE NUDGED UPWARD. INTO WEDNESDAY...THERE LOOKS TO BE LITTLE
CHANGE IN THE MEAN PATTERN AND ASSOCIATED SENSIBLE WX...DIURNALLY
ENHANCED TSTM CHANCES. DAILY TEMPERATURES WILL CONTINUE TO BE WITHIN
A FEW DEGREES OF CLIMO. I WOULD EXPECT ABOVE CLIMO TSTM CHANCES TO
CONTINUE INTO THURSDAY AS WELL GIVEN THE ONLY NOMINAL CHANGE TO THE
PATTERN ACRS THE EASTERN CONUS. THE LATEST ECMWF IS HINTING AT A
TRANSITION TOWARD A WEAKER/DEAMPLIFYING FLOW REGIME BY THE END OF
PERIOD. NEW DAY 7 POPS WILL FEATURE SLIGHT AND/OR SMALL DIURNAL
TSTM CHANCES AND TEMPERATURES NEAR PERSISTENCE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...TIMING OF CONVECTION AT THE AIRPORT IS MAIN PROBLEM.
LATEST LOCAL WRF RUN SEEMS TO BE CAPTURING CONVECTIVE TRENDS AND IT
SUGGESTS THUNDERSTORMS AROUND 20Z FOR THE AIRFIELD. HENCE...WILL
RUN A TEMPO FOR TSRA FROM 20-22Z AND THEN A VCSH TIL AROUND 00Z.
EXPECT AFTER 00Z ONLY SOME CONVECTIVE DEBRIS CLOUDS. IF
SUBSTANTIAL RAIN OCCURS AT THE AIRFIELD...CANT RULE OUT SOME MVFR
TYPE FOG EARLY ON SAT...BUT FOR NOW HAVE NOT INTRODUCED THAT. ON
SAT...THE MORNING SHOULD BE QUIET WITH CONVECTION ARRIVING AFTER
THIS TAF TIMEFRAME.
ELSEWHERE...SCATTERED TO NUMEROUS THUNDERSTORMS THIS AFTERNOON
ACROSS THE AREA TRIGGERED BY AN UPPER AIR DISTURBANCE.
HENCE...EXPECT ALL AIRFIELDS TO BE AFFECTED IN APPROXIMATELY 19Z-23Z
TIMEFRAME. EXPECT CONVECTION TO WANE QUICKLY AFTER 00Z AS TROUGH
MOVES TO THE EAST. EXPECT SOME IFR/LIFR MOUNTAIN VALLEY FOG AND
AROUND KHKY AS EXPECT MOST AREAS TO HAVE SOME RAINFALL.
CONVECTION ON SAT SHOULD BE AFTER THJIS TAF PERIOD.
OUTLOOK...A DAILY CHANCE OF SCT AFTERNOON CONVECTION WILL THEN
CONTINUE INTO THE MIDDLE OF NEXT WEEK AS AN UPPER TROF REMAINS OVER
THE AREA.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR GAZ029.
NC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NCZ071-072-082.
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ009-011>014-
019.
&&
$$
SYNOPSIS...JDL
NEAR TERM...LG
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...LG
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
331 PM CDT FRI JUL 27 2012
.DISCUSSION...
A WEAKNESS IN THE BUILDING HIGH PRESSURE RIDGE ALOFT WILL AFFECT
SE TX TONIGHT AND POSSIBLY DURING THE EARLY TO MID PART OF NEXT
WEEK. OUTFLOW BOUNDARIES FROM THUNDERSTORMS THAT AFFECTED NE TX
AND NW LA EARLIER TODAY SHOULD WORK THEIR WAY INTO THE EASTERN
COUNTIES OF THE FORECAST AREA TONIGHT. THE RAP AND GFS BOTH
INDICATE AT LEAST ISOLATED CONVECTION IS POSSIBLE WITH THE NAM
SHOWING THE RAIN CHANCES JUST TO THE EAST. GIVEN THE WEAKNESS
ALOFT AND THE MODEL OUTPUT...DECIDED TO GO WITH ISOLATED POPS
TONIGHT GENERALLY ALONG AND NORTHEAST OF A LINE FROM AUSTONIO TO
LIBERTY. AS THE WEAKNESS MOVES SLOWLY EASTWARD...ISOLATED SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO LINGER OVER THE COASTAL WATERS
ON SUNDAY.
THE HIGH PRESSURE RIDGE ALOFT WILL BUILD OVER SE TX OVER THE
WEEKEND...AND BRING SOUTHWESTERLY WINDS AND HOT DAYTIME
TEMPERATURES. SOME LOCATIONS MAY REACH TO NEAR 100 ON SATURDAY
AND LIKELY ON BOTH SUNDAY AND MONDAY. THE CENTER OF THE RIDGE IS
FORECAST TO MOVE SLIGHTLY WESTWARD AS THE WEAKNESS DEEPENS
SLIGHTLY AFTER MONDAY. THERE IS SOME UNCERTAINTY AS TO HOW STRONG
THE RIDGE WILL BE AND HOW FAR WEST IT WILL MOVE NEXT WEEK BETWEEN
THE GFS AND ECMWF. BECAUSE OF THIS...RAIN CHANCES WILL STAY LOW
THROUGH WEDNESDAY AND DAYTIME TEMPERATURES WILL REACH AT LEAST
INTO THE MID AND UPPER 90S.
40
&&
.MARINE...
PRESSURE GRADIENT WILL RELAX OVER THE NEXT SEVERAL DAYS LEADING TO
LIGHT WINDS AND LOW SEAS. SHOULD SEE A PROMINENT LANDBREEZE/
SEABREEZE CIRCULATION SET UP THIS WEEKEND. 47
&&
.PREV DISCUSSION... /ISSUED 1225 PM CDT FRI JUL 27 2012/
AVIATION...
MAY SEE ONE OR TWO CELLS POP UP LATER THIS AFTN...BUT NOT WORTH
MENTIONING IN TAFS ATTM. OTHERWISE...VFR THRU MAJORITY OF THE NEXT
24-30+ HOURS. KEPT THE MENTION OF LATE NIGHT/EARLY MORNING MVFR
FOG AT THE SAME NON-METRO TERMINALS THAT HAD IT LAST NIGHT. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 77 98 76 100 77 / 10 10 10 10 10
HOUSTON (IAH) 77 96 77 98 77 / 10 10 10 10 10
GALVESTON (GLS) 82 93 82 92 82 / 10 10 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1206 PM EDT FRI JUL 27 2012
.SYNOPSIS...
SHOWER AND THUNDERSTORM ACTIVITY WILL BE SCATTERED ACROSS THE AREA
THIS AFTERNOON AS A SLOW MOVING COLD FRONT APPROACHES FROM THE
NORTHWEST. THIS COLD FRONT WILL EXIT OUR AREA TO THE EAST BY
SATURDAY AFTERNOON...WITH HIGH PRESSURE BUILDING IN FROM THE GREAT
LAKES FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130 AM...
NEAR FULL SUN ONGOING EAST OF BLUE RIDGE WHICH SHOULD PROMOTE
STRONG INSTABILITY TO FUEL STRONG TO SEVERE STORMS THIS AFTERNOON.
THE STORM PREDICTION CENTER CONTINUES TO MAINTAIN SLIGHT RISK FOR
SEVERE STORMS ALONG AND EAST OF BLUE RIDGE...MAIN THREAT DAMAGING
WINDS.
MORNING RNK SOUNDING WAS NOT OVERLY IMPRESSIVE DUE TO DEBRIS
REMANTS FROM MCS TO OUR NORTH LAST NIGHT...TEMPS ALOFT STILL WARM
AND WINDS WESTERLY. MODIFIED SOUNDING FOR THE AFTERNOON HOWEVER
SUGGESTS A MORE RESPECTIBLE ENVIRONMENT FOR STORM GROWTH...CAPES
2000-3000...AND STEEPER MID LEVEL LAPSE RATES PER COOLING TEMPS
ALOFT COOLING FROM APPROACHING UPPER TROUGH. AS WE TRANSITION
THROUGH THE AFTERNOON ANTICIPATE BACKING OF THE LOWER LEVEL WIND
AHEAD OF THE APPROACHING TROUGH...YIELDING INCREASING CONVERGENCE
ALONG THE BLUE RIDGE. LEE TROUGH SHOULD ALSO STRENGTHEN PER
INTENSE AFTERNOON HEATING FURTHER INCREASING THE CONVERGENCE EAST
OF THE BLUE RIDGE.
BOTH THE RNK WRF AND HRRR SUGGEST INBOUND SHRA/TSRA ACTIVITY FROM WV
WILL BE JOINED BY NEW DEVELOPMENT VCNTY OF BLUE RIDGE AND LEE
TROF. AS SUCH MAY END UP WITH SEVERAL BANDS OR STORM CLUSTERS
WHICH WILL THEN MOVE EAST BOUND TOWARD THE COAST DURING THE LATE
AFTERNOON AND EVENING.
FOR OUR CWA...THE GREATEST INSTABILITY WILL RESIDE OVER OUR
EASTERN COUNTIES...THUS EXPECT TO SEE STRONGEST THUNDERSTORM
ACTIVITY FOR OUR PIEDMONT COUNTIES...MAINLY SOUTH AND EAST OF THE
ROANOKE VALLEY. MODELS HAVE ALL OF THE ACTIVITY CLEARING THE CWA
AROUND SUNSET.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 425 AM EDT FRIDAY...
UPPER ATMOSPHERIC PATTERN WILL CONTINUE TO AMPLIFY THROUGH THE SHORT
TERM AS THE SUBTROPICAL RIDGE GAINS STRENGTH AND AMPLITUDE ACROSS
THE CENTRAL/SOUTHERN PLAINS ONCE AGAIN. THIS WILL LEAD TO ENHANCED
NORTHWEST FLOW ACROSS THE MID-ATLANTIC REGION DURING THE WEEKEND. A
SERIES OF DISTURBANCES IN THE PERSISTENT NW FLOW ALOFT WILL FINALLY
SHIFT THE MAIN UPPER TROUGH AXIS TO THE EAST SIDE OF THE CWA BY LATE
SAT...THEN RESULT IN A GENERALLY QUASI-STATIONARY PATTERN ACROSS THE
U.S. INTO EARLY NEXT WEEK FEATURING A LINGERING UPPER
TROUGH...CENTERED JUST EAST OF THE CWA THROUGH MUCH OF THE PERIOD. A
CONTINUED SERIES OF DISTURBANCES TRACKING IN NW FLOW ON THE BACKSIDE
OF THIS UPPER TROUGH WILL KEEP A FAIRLY ACTIVE PATTERN IN PLACE.
ALTHOUGH THE UPPER PATTERN DOES NOT CHANGE SUBSTANTIALLY THROUGH THE
PERIOD...DAY-TO-DAY CONVECTIVE CHANCES WILL. FOR SAT...THE BEST
LOW-LEVEL AIR MASS HAS SHIFTED EAST OF THE CWA...BUT NOTICEABLY
COLDER AIR ALOFT AND PVA IN AFOREMENTIONED NW FLOW ALOFT WILL
ENHANCE PCPN...ESPECIALLY THAT WHICH IS OROGRAPHICALLY INDUCED
ACROSS THE NORTHERN ALLEGHANYS AND THE SW BLUE RIDGE. FOR SUN...THE
BEST UPPER SUPPORT AND LOW-LEVEL MOISTURE HAS SHIFTED EAST OF THE
REGION...LEAVING THE CWA IN A MORE STABLE...DRIER AIR MASS. AT THIS
POINT...WITH THE MAIN TROUGH AXIS EAST OF THE REGION...HAVE LIMITED
POPS TO JUST THOSE OROGRAPHICALLY AND DIURNALLY INDUCED. BY
MON...NEW DISTURBANCES ORIGINATING IN THE NORTHERN PLAINS/SC CANADA
WILL TRACK TOWARD THE REGION...RESULTING IN A SLOW RETROGRESSION OF
THE UPPER TROUGH. HENCE...EXPECT DIURNAL CONVECTION TO BE ON THE
INCREASE ONCE AGAIN MON...ESPECIALLY ON THE EAST SIDE OF THE
ALLEGHANYS WHERE DEEPER LOW-LEVEL MOISTURE AND SE-S SFC FLOW SHOULD
EXIST.
MAX/MIN TEMPS DURING THE PERIOD SHOULD BE CLOSER TO SEASONAL NORMALS
THAN THE PAST FEW DAYS...BUT LIKELY REMAINING SLIGHTLY AOA NORMALS
WITH 850MB TEMPS STILL IN THE +18-+20C RANGE SAT-SUN. GREATER
INSOLATION...ESPECIALLY SUN...WILL ALSO OFFSET THE SLIGHTLY LOWER
LOW-LEVEL THICKNESSES AND 850MB TEMPS. THE MAIN CHANGE WILL BE
NOTICED WITH SLIGHTLY LOWER DEWPOINTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 425 AM EDT FRIDAY...
THE BLOCKING PATTERN WHICH BECOMES ESTABLISHED DURING THE SHORT TERM
REMAINS IN PLACE THROUGHOUT NEXT WEEK WITH A STRONG UPPER RIDGE
ANCHORED ACROSS IN THE TX/OK/NM REGION...ANOTHER STRONG RIDGE OFF
THE MID-ATLANTIC COAST...AND A GENERAL BROAD UPPER TROUGH ACROSS THE
EASTERN U.S. THIS UPPER TROUGH SLOWLY RETROGRADES THROUGH THE
EXTENDED PERIODS...WHICH SLOWLY RESULTS IN THE CWA TRANSITION FROM
NW FLOW ALOFT AT THE BEGINNING OF THE LONG TERM PERIOD TO A
SOUTHWEST FLOW ALOFT BY THE END OF THE PERIOD. LOW-LEVEL MOISTURE
AND PWATS CONTINUE TO INCREASE...ALL RESULTING IN ENHANCED CHANCES
FOR DIURNAL CONVECTION AND CLOUD COVER. EXPECT SCT-NMRS DIURNAL
CONVECTION THROUGH THE PERIOD. AT THIS POINT...TUE-WED APPEAR TO
OFFER THE BETTER CHCS FOR CONVECTIVE COVERAGE WITH BETTER UPPER
DYNAMICS IN PLACE...BUT GIVEN MODEL UNCERTAINTIES...AT LEAST CHC
POPS WILL REMAIN IN PLACE THROUGHOUT THE ENTIRE PERIOD. THE CLOUD
COVER WILL HOLD MAX TEMPS NEAR OR SLIGHTLY BELOW NORMAL...WHILE MIN
TEMPS WILL REMAIN AOA NORMAL WITH WARM MUGGY NIGHTS.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
AS OF NOON FRIDAY...
ANTICIPATING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP OVER THE MOUNTAINS AND MOVE EAST THROUGH THE PIEDMONT THIS
AFTERNOON. SOME OF THE STORMS COULD BE SEVERE WITH ISOLATED WIND
GUSTS OF 50 KTS. CONDITIONS WILL BE PRIMARILY VFR EXCEPT IN THE
VCNTY OF THE SHRA/TSRA. STORM THREAT GREATEST BETWEEN
2-5PM...DIMINISHING TOWARD SUNSET...SOME VFR DEBIS CLOUDINESS
LINGERING OVERNIGHT TONIGHT. WINDS TODAY WILL BE WESTERLY
GENERALLY 7-10KTS WITH SOME LOW END 16-18KT GUSTS. HIGHER GUSTS
LIKELY IN THE VCNTY OF THE STORMS.
THE MAIN SURFACE COLD FRONT WILL PUSH THROUGH THE FORECAST AREA
ON SATURDAY MORNING AND AFTERNOON. ADDITIONAL SHOWERS AND
THUNDERSTORMS...WITH SUB-VFR CONDITIONS ARE POSSIBLY THROUGH
SATURDAY EVENING.
THE AIR MASS DRIES OUT AND VFR PREVAILS ACROSS THE REGION SATURDAY
NIGHT INTO EARLY MONDAY. RETURN MOISTURE AND RESIDUAL FRONT TO THE
SOUTH WILL LIKELY RESULT IN MORE DIURNALLY DRIVEN CONVECTION
MONDAY INTO TUESDAY...BUT MAINLY VFR OUTSIDE OF AFTERNOON STORMS
AND OVERNIGHT VALLEY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...PM
SHORT TERM...JC
LONG TERM...JC
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
308 PM CDT FRI JUL 27 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COMPACT UPPER
SHORTWAVE MOVING EAST OVER NORTHERN LAKE MICHIGAN EARLY THIS
AFTERNOON. SCATTERED TO NUMEROUS SHOWER ACTIVITY CONTINUES TO
DEVELOP AND ROTATE AROUND THE SHORTWAVE ACROSS MUCH OF NORTHEAST AND
CENTRAL WISCONSIN. NORTH-CENTRAL WISCONSIN HAS BEEN THE LONE DRY
SPOT TODAY AND CLEARING IS BEGINNING TO WORK INTO VILAS COUNTY FROM
THE NORTH. HIGH PRESSURE RESIDES OVER THE NORTHERN MISSISSIPPI
VALLEY AND THE DAKOTAS WHERE MOSTLY CLEAR TO PARTLY CLOUDY
CONDITIONS ARE OCCURRING. THE MAIN FORECAST CONCERNS ARE TIMING THE
END OF THE SHOWER ACTIVITY AND FOG/TEMPS.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE TO THE EASTERN GREAT LAKES
TONIGHT WHILE HIGH PRESSURE BUILDS INTO THE REGION IN ITS WAKE.
PLENTY OF LOW LEVEL MOISTURE UPSTREAM ALL THE WAY WEST TO MINNESOTA
AND DRY AIR ADVECTION IS WEAK...SO IT MAY TAKE AWHILE FOR CLOUDS TO
CLEAR. SHOULD SEE THE CLEARING WORK FROM NW TO SE THROUGH THE NIGHT
THOUGH. HAVE INCREASED SKY COVER THIS EVENING BUT STILL TAKE SKY
CONDITIONS MOSTLY CLEAR OVERNIGHT. AFTER SEVERAL ROUND OF RAINFALL
THE PAST FEW DAYS...MOIST SOIL CONDITIONS WILL BE SUPPORTIVE FOR FOG
OVERNIGHT. WILL ADD AREAS OF DENSE FOG TO THE FORECAST FOR
NORTH-CENTRAL WISCONSIN. LOWS RANGING FROM THE UPPER 40S NORTH TO
AROUND 60 SOUTH.
SATURDAY...HIGH PRESSURE WILL BE OVER THE AREA AND WILL LEAD TO DRY
CONDITIONS. THE 12Z NAM IS MORE BULLISH IN KEEPING THE LOW LEVEL
MOISTURE AROUND FOR TOMORROW...WHICH SHOULD LEAD TO A DECENT CU
FIELD DEVELOPING BY LATE MORNING. UPSTREAM OBS SUPPORT THIS OVER
MINNESOTA SO WILL PORTRAY PARTLY CLOUDY CONDITIONS FOR THE
AFTERNOON. HIGHS WILL BE SEASONABLE AROUND THE UPPER 70S TO LOWER
80S.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY.
THE PRIMARY CONCERNS DURING THIS PART OF THE FORECAST ARE TIMING OF
UPPER LEVEL SHORT WAVES AND ASSOCIATED PRECIPITATION CHANCES.
A CLOSED 500MB LOW IN THE VICINITY OF HUDSON BAY AND A WEAK RIDGE
OVER THE CENTRAL/WESTERN CONUS WILL KEEP THE REGION IN WEST-
NORTHWEST FLOW ALOFT. MEDIUM RANGE MODELS WERE NOT IN THE BEST OF
AGREEMENT...BUT DID HAVE SOME QPF FORECAST IN/AROUND THE AREA
SATURDAY NIGHT AND SUNDAY. SHORT WAVE ENERGY AND A WEAK SURFACE
BOUNDARY MOVING INTO WISCONSIN FROM THE NORTH WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS ON TUESDAY. SURFACE HIGH PRESSURE
SHOULD KEEP TUESDAY NIGHT DRY BEFORE MODELS BRING THE NEXT SHORT
WAVE AND SURFACE BOUNDARY INTO THE FORECAST AREA...KEEPING A
CHANCE OF SHOWERS AND STORMS AROUND THROUGH THURSDAY. SURFACE HIGH
PRESSURE BUILDING IN BEHIND THE DEPARTING FRONT SHOULD KEEP
FRIDAY DRY.
DO NOT REALLY SEE A REASON FOR TEMPERATURES TO WARM INTO THE 90S
IN THE NEAR FUTURE. LOOKS LIKE READINGS SHOULD BE CLOSER TO
SEASONAL NORMALS.
&&
.AVIATION...UPPER LEVEL LOW PRESSURE WILL EXIT THE REGION BY EARLY
THIS EVENING. WILL TAKE SOME TIME FOR THE LOW LEVELS TO DRY OUT AND
NOT ENTIRELY SURE THAT SKIES WILL CLEAR THIS EVENING. BUT GUIDANCE
STILL SUPPORTS THIS SO DID NOT MAKE TOO MANY CHANGES TO THE FORECAST
THIS EVENING ONWARD. STILL THINK WILL SEE SCT-NMRS SHOWERS AND
ISOLD THUNDERSTORMS OVER THE FOX VALLEY THROUGH MID TO LATE
AFTERNOON. COVERAGE OF SHOWERS MORE SPOTTY EVERYWHERE ELSE.
CLEARING SKIES AND LIGHT WINDS LATE TONIGHT WILL SUPPORT AREAS OF
FOG DEVELOPING. SHOULD SEE DENSE FOG AT TIMES WITHIN THE LOW LYING
AREAS AND COLD SPOTS. HIGH PRESSURE OVER THE REGION TOMORROW...BUT
AMPLE LOW LEVEL MOISTURE WILL LEAD TO CU BUILD UP BY MIDDAY.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/MG