Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/29/13
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
127 PM PDT SAT JUL 27 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE OFF THE WEST COAST WILL BRING DRYING
THROUGH MONDAY AND GUSTY WESTERLY WINDS IN THE MOUNTAINS AND
DESERTS. THE MARINE LAYER WILL DEEPEN SLIGHTLY THROUGH SUNDAY...
BRINGING LOW CLOUDS AND FOG INTO THE FAR INLAND VALLEYS EACH
MORNING...AND LIMITED CLEARING ALONG AT THE BEACHES. THE CLOUDS AND
ONSHORE FLOW WILL HOLD DAYTIME TEMPERATURES A BIT BELOW AVERAGE. FOR
NEXT WEEK...SOUTHWEST FLOW ALOFT WILL KEEP THE MONSOON AT BAY...AND
ONSHORE FLOW WILL CONTINUE THE MARINE CLOUDS AND FOG EACH NIGHT AND
MORNING ALONG THE COAST AND INTO THE VALLEYS. SLIGHTLY WARMER FOR
THE LATTER HALF OF THE WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THE STRATUS LAYER EVIDENTLY WAS SOLID THIS MORNING WHICH ALLOWED IT
TO HOLD ON DESPITE THE STRONG MID-SUMMER SUN. LOOKS LIKE IT MAY BE
MAKING UP FOR LOST TIME IN MAY/JUNE. IN ANY CASE IT REMAINS SOLID
ALONG THE COAST AT 1 PM PDT AND WITH UNUSUALLY DEEP PENETRATION INTO
COASTAL SAN DIEGO COUNTY FOR THIS TIME OF YEAR AND HOUR OF THE DAY.
WEAK OFFSHORE GRADIENTS TO NV ARE NOT HELPING...BUT MODERATE ONSHORE
SFC PRESSURE GRADIENTS ARE IN PLACE TO THE LOWER DESERTS.
A WEAK UPPER LOW CENTERED ABOUT 300 MILES W OF POINT CONCEPTION...
WILL DRIFT SLOWLY SE THROUGH MON...WHILE HIGH PRESSURE OVER NM/AZ
SINKS SE. THIS WILL CONTINUE THE DRYING TREND AND SUPPORT THE MARINE
LAYER AND ASSOCIATED STRATUS THROUGH MON. FOR NEXT WEEK...THE
SUBTROPICAL HIGH WILL REMAIN SUBDUED OVER THE RIO GRANDE AREA WHILE
A STRONGER TROUGH MOVES ACROSS THE PACNW. THIS WILL KEEP SOCAL IN A
DRY SW FLOW ALOFT...WHICH SHOULD HOLD THE MONSOON AT BAY.
MAIN FORECAST CONCERN FOR THE DAY WILL BE THUNDERSTORMS AND
COVERAGE. JUST AFTER NOON CU WERE BUBBLING ALONG THE MOUNTAIN CRESTS
AND OVER THE DESERTS. A FEW WERE BIG ENOUGH TO DROP SOME RAIN IN THE
SAN BERNARDINO MTNS. LATEST HRRR MODEL AND THE 18Z RUN OF THE NAM 12
BOTH SHOW PRECIP IN THE MTNS. MOISTURE IS SUFFICIENT...AND MID-LEVEL
WINDS ARE LIGHT ENOUGH TO ENCOURAGE CONVECTION ON THE ELEVATED
TERRAIN IN THESE AREAS...BUT INSTABILITY IS MARGINAL AND THE FLOW IS
WESTERLY ALOFT WHICH SHOULD LIMIT THE EXTENT OF THIS ACTIVITY AS IT
MOVES NE INTO THE DESERTS. CONTINUED DRYING AND WESTERLY FLOW ALOFT
WILL UNDERMINE ANY FURTHER DEVELOPMENT FOR SUNDAY AFTERNOON.
FOR COASTAL AREAS...EXPECT EXTENSIVE NOCTURNAL STRATUS DEVELOPMENT
EACH NIGHT THROUGH TUE...BUT MORE TYPICAL OF LATE JULY...IT SHOULD
BURN OFF BETTER EACH AFTERNOON AS THE INVERSION WEAKENS SLIGHTLY.
SOME BEACHES MAY REMAIN OVERCAST WELL INTO THE AFTERNOONS HOWEVER.
THE MARINE LAYER WILL RETREAT SLIGHTLY DURING THE LATTER HALF OF THE
WEEK FOR FASTER CLEARING AND SLIGHT WARMING. THE ONSHORE PATTERN
WILL SUPPORT GUSTY WINDS THROUGH THE MOUNTAIN PASSES AND INTO THE
DESERTS EACH AFT/EVE...AND HOLD DAYTIME TEMPERATURES A BIT BELOW
AVERAGE THROUGH MID WEEK.
&&
.AVIATION...
2702015Z...COASTS/VALLEYS...LOW CLOUDS BASED 500-900 FT MSL AND TOPS
TO 2000 FT MSL WILL MOVE BACK INTO THE REMAINING COASTAL AIRPORTS
THIS EVENING AROUND 02-06Z. THE LOW CLOUDS SHOULD SPREADING INLAND
OVERNIGHT TO AS FAR AS KRNM...BUT STILL WEST OF KONT. THE LOW CLOUDS
SHOULD CLEAR AROUND 16-17Z INLAND ON SUNDAY...BUT REMAIN BKN-OVC AT
AROUND 1000 FEET MSL COASTAL WATERS AND LOCALLY INLAND. LOCAL
VISIBILITIES BELOW 3SM IN FOG NEAR THE INLAND EDGE OF THE LOW CLOUDS
SUNDAY MORNING. OTHERWISE...SCT-BKN CLOUDS AOA 10000 FT MSL.
MTNS/DESERTS...CU/TCU AND ISOLATED TSTMS OVER THE MTN RIDGES AND
HIGH DESERTS...MAINLY NORTH OF BANNING PASS...ENDING AROUND 28/02Z
THIS AFTERNOON. BASES WILL BE AROUND 10000 FEET WITH TOPS TO 35000
FEET. OTHERWISE...SCT-BKN CLOUDS AOA 10000 FT MSL AND UNRESTRICTED
VSBY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...JAD
AVIATION/MARINE...SMALL
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
716 PM MDT SUN JUL 28 2013
.UPDATE...
&&
.SHORT TERM...PRECIP HAS PRETTY MUCH ENDED IN MOST AREAS SO WILL
DECREASE POPS FOR THE REST OF THIS EVENING.
.AVIATION...WINDS ARE SUPPOSED TO BECOME DRAINAGE LATER THIS
EVENING AS WK DENVER CYCLONE EVENTUALLY FORMS OVER SOUTHERN WELD
COUNTY AFTER 06Z. THERE ARE LARGE DIFFERENCES BETWEEN THE HRRR
AND RAP AS TO WHETHER FOG AND LOW CLOUDS AFFECT DIA TOWARDS
SUNRISE. THE RAP KEEPS THEM TO THE NORTH AND EAST WHILE THE HRRR
BRINGS IN LOW CEILINGS AND DENSE FOG AROUND 11Z. WILL LOOK AT
LATER DATA TO SEE WHICH WAY TO GO WITH THE 03Z UPDATE.
&&
.PREV DISCUSSION... /ISSUED 327 PM MDT SUN JUL 28 2013/
SHORT TERM...FOR THE REST OF THIS AFTERNOON AND TONIGHT...SHOWERS
CONTINUE TO STREAM ACROSS EASTERN COLORADO AHEAD OF AN UPPER LEVEL
TROUGH. EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP WHERE
SKIES ARE ABLE TO CLEAR FOR A SHORT TIME. BASED ON ACCAR
SOUNDINGS...JUST NEED TO REACH 72-73 TO HIT THE CONVECTIVE
TEMPERATURE. BETTER CHANCE FOR REACHING CONVECTIVE TEMPERATURE OVER
THE HIGHER TERRAIN WHERE IT WILL PARTIALLY CLEAR SOONER. CAPES WILL
BE LESS THAN 1000 J/KG SO ANY CONVECTION THAT FORMS SHOULD STAY
BELOW SEVERE LIMITS. DUE TO HIGH PRECIPITABLE WATER VALUES...A BRIEF
PERIOD OF HEAVY RAIN WILL BE POSSIBLE. SHOWERS AND STORMS WILL
DECREASE AFTER MID EVENING AS THE AIRMASS STABILIZES AND THE SHORT
WAVE TROUGH EXITS THE AREA. LOW CLOUDS AND PATCHY FOG WILL BE
POSSIBLE OVER THE EASTERN PLAINS AFTER MIDNIGHT.
ON MONDAY...AIRMASS WILL BE DRYING MONDAY...BUT MOIST ENOUGH FOR A
ROUND OF LATE DAY SHOWERS AND THUNDERSTORMS. INSTABILITY WILL BE
LIMITED WITH CAPES UNDER 1000 J/KG. STORMS WILL INITIATE OVER THE
HIGHER TERRAIN AND PROGRESS EASTWARD. SMALL HAIL AND A BRIEF PERIOD
OF HEAVY RAIN WILL BE POSSIBLE. WILL SEE SOME SUN MONDAY WHICH WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOWER 80S.
LONG TERM...ZONAL FLOW OVER THE TOP OF THE UPPER RIDGE CENTERED
NEAR EL PASO MONDAY EVENING GRADUALLY BECOMES NORTHWESTERLY OVER THE
FORECAST AREA ON TUESDAY WITH RISING HEIGHT TENDENCIES TOWARDS THE
FOUR CORNERS REGION. PRECIPITABLE WATER VALUES FALL ON TUESDAY UNDER
AN HALF INCH OVER THE HIGH COUNTRY AND BELOW AN INCH ON THE PLAINS.
STRENGTHENING STABILITY WITHIN THE 600-400MB LAYER AND LESS MOISTURE
POINT TO FAR LESS CONVECTION ON TUESDAY. MAY STILL SEE A FEW WEAK
SHOWERS/STORMS FORM OVER THE HIGH TERRAIN BY EARLY AFTERNOON...BUT
ANY PCPN FROM THEM IS EXPECTED TO BE LIGHT. MAY SEE MORE WIND GUSTS
FM THESE WITH THE MUCH DRIER SUB-CLOUD ENVIRONMENT. ON THE PLAINS A
10-15KT NORTHWESTERLY FLOW OFF THE FRONT RANGE AND CHEYENNE RIDGE
WILL FURTHER DRY OUT LOWER LEVELS THROUGH THE DAY PARTICULARLY UP
AGAINST THE FOOTHILLS. THE CHANCE FOR T-STORMS WITHIN THE I-25 URBAN
CORRIDOR APPEARS QUITE LOW...PERHAPS LESS THAN 10 PCT. HOWEVER
FARTHER OUT ON THE PLAINS PW VALUES STILL UP AROUND AN INCH AND SFC
DEWPOINTS STILL UP NEAR 60F. NAM AND GFS INDICATE A NORTH-SOUTH BAND
OF 1000-1500 J/KG SFC BASED CAPE ACROSS LOGAN...EASTERN
WASHINGTON...PHILLIPS AND SEDGWICK COUNTIES LATE AFTERNOON AND EARLY
EVENING. HOWEVER MODELS ALSO INDICATE A FAIR AMOUNT OF CIN OUT
THERE. IF NOT FOR THE WEAK INSTABILITY AND QG ASCENT PRODUCED BY A
PASSING MID-LEVEL SHORTWAVE...WOULD HAVE REMOVED ANY MENTION OF
STORMS OUT THERE. WITH THAT IN MIND...FOR NOW WILL KEEP A CHANCE OF
T-STORMS INTO THE EVENING HRS IN THE 4 COUNTIES MENTIONED ABOVE AND
A SLIGHT CHANCE OF T-STORMS ALONG THE PALMER DIVIDE EAST ACROSS
SOUTHERN ELBERT AND LINCOLN COUNTIES. CAN NOT RULE A STORM BRIEFLY
GOING SEVERE IN THE NORTHEAST CORNER... BUT ODDS OF THAT APPEAR
QUITE LOW. TEMPERATURES ON TUESDAY ARE FORECAST TO WARM 2-3DEG C
ABOVE THOSE ON MONDAY. HAVE NO PROBLEM WITH THAT.
FOR THE REMAINDER OF THE WEEK...TEMPERATURES ALOFT CONTINUE TO WARM
AS THE UPPER RIDGE JUST WEST OF COLORADO SLOWLY MIGRATES OVER THE
STATE BY THURSDAY. LOW-LEVEL MOISTURE EAST OF THE MOUNTAINS APPEARS
TO REMAIN IN PLACE THROUGH THE PERIOD AND WITH THE USUAL DAILY CYCLE
OF UPSLOPE FLOW GENERATED BY STG SOLAR HEATING...AT LEAST A SLIGHT
CHANCE OF AFTERNOON AND EVENING T-STORMS IS WARRANTED FOR JUST ABOUT
EVERYWHERE. LIGHTNING...SPOTTY RAINFALL AND GUSTY OUTFLOW WINDS
PRETTY MUCH ALL THIS CONVECTIVE SHOULD PRODUCE...WITH TEMPERATURES
NEAR TO SLIGHTLY ABOVE AVERAGE ON WEDNESDAY AND THURSDAY. FRIDAY
THROUGH SUNDAY...MEDIUM RANGE MODEL GUIDANCE SHOWS THE UPPER RIDGE
SHIFTING EAST OF COLORADO PLACING THE STATE UNDER SOUTHWEST FLOW
ALOFT. THIS ALLOWS THE FLOW OF SUBTROPICAL MOISTURE FROM THE DESERT
SOUTHWEST TO RESUME. PRECIPITABLE WATER VALUES GRADUALLY RISE
THROUGH THE PERIOD THEREBY INCREASING THE ODDS OF THUNDERSTORMS...
INITIALLY OVER THE HIGHER ELEVATIONS. MODELS ALSO SHOW A SFC HIGH
SLIPPING SOUTH OUT OF WYOMING FRIDAY NIGHT WHICH HELPS TO ENHANCE
THE NORMAL EASTERLY/UPSLOPE FLOW EAST OF THE MTNS. THIS MAY STABLIZE
THE PLAINS WITH INFLUX OF SLIGHTLY COOLER AIR. HOWEVER HUMIDITIES
SHOULD ALSO INCREASE. SO RAIN/STORM CHANCES MAY RISE OVER THE
WEEKEND.
AVIATION...SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER INTO THE
MID EVENING HOURS. CEILINGS WILL SLOWLY INCREASE TO 3000 TO 5000
FEET THROUGH THIS EVENING. ANOTHER CHANCE FOR LOW CLOUDS AND FOG
LATE TONIGHT AND MONDAY MORNING. IT WILL BE DRIER MONDAY...BUT BY
MID AFTERNOON THE CHANCE FOR SHOWERS AND STORMS RETURN. WINDS WILL
BE ON THE LIGHT SIDE FOR THE NEXT 24 HOURS.
HYDROLOGY...MOIST AIRMASS WILL REMAIN IN PLACE. ISOLATED TO
SCATTERED THUNDERSTORMS ARE EXPECTED THROUGH EARLY EVENING. STORMS
WILL BE MOVING AT 10 TO 20 MPH...SO ONLY A BRIEF PERIOD OF HEAVY
RAIN IS POSSIBLE. THIS WILL KEEP THE THREAT FOR FLASH FLOODING LOW.
THERE WILL BE A BETTER CHANCE FOR THUNDERSTORMS MONDAY AFTERNOON AND
EARLY EVENING. AGAIN STORMS WILL BE MOVING ALONG A GOOD CLIP...WHICH
WILL KEEP THE FLASH FLOOD THREAT LOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....BAKER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MIAMI FL
233 PM EDT SAT JUL 27 2013
.DISCUSSION...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS AFTERNOON
ACROSS THE INTERIOR AND EAST COAST DUE TO DAYTIME HEATING...SEA
BREEZE BOUNDARIES AND THE INFLUENCE OF A LOW LEVEL TROUGH. THE
LOW LEVEL TROUGH WILL BEGIN TO SLIDE TO THE NORTHEAST
TONIGHT...PUSHING THE DEEP LOW LEVEL MOISTURE CLOSER TO THE EAST
COAST. THE HRRR AND GFS BOTH SHOW SCATTERED SHOWERS REDEVELOPING
ACROSS THE EAST COAST METRO AREAS AFTER 00Z. THESE SHOWERS MAY
THEN PUSH OFF THE COAST AFTER 06Z. AN UPPER LEVEL SHORTWAVE IS
FORECAST TO DIVE SOUTHEAST INTO NORTHERN FLORIDA OVERNIGHT...AND
THERE MAY BE SOME UPPER DIVERGENCE ACROSS SOUTH FLORIDA AS WELL.
COASTAL CONVERGENCE ALONG THE EAST COAST OF PALM BEACH COUNTY
LATE IN THE NIGHT AND TOWARDS DAYBREAK MAY HELP STORMS REDEVELOP
RIGHT ALONG THE COAST.
THE LOW LEVEL TROUGH WILL CONTINUE TO LIFT NORTHEAST AND THE
SUBTROPICAL RIDGE WILL BEGIN TO NOSE INTO THE REGION DURING THE
DAY ON SUNDAY. SO THE DEEPEST MOISTURE IS EXPECTED TO LIFT OUT OF
SOUTH FLORIDA BY THE AFTERNOON. HOWEVER...THERE WILL STILL BE
UPPER LEVEL DIVERGENCE...AND MOISTURE LEVELS WILL BE NEAR NORMAL.
SO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE
REGION...EXCEPT FOR THE IMMEDIATE GULF COAST. THE MAIN THREAT
AGAIN FOR SUNDAY WILL BE LOCALLY HEAVY RAIN/FLOODING AND GUSTY
WINDS.
THE UPPER TROUGH WILL BEGIN TO LIFT NORTHWARD AS THE SUBTROPICAL
RIDGE BUILDS INTO SOUTH FLORIDA. EASTERLY FLOW WILL RETURN WITH A
MORE TYPICAL PATTERN OF ISOLATED MORNING SHOWERS FOR THE EAST
COAST...AND THEN SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS
ALONG THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR AND TOWARDS
THE GULF COAST. THIS PATTERN IS FORECAST TO PERSIST THROUGH THE
MIDDLE OF THE WEEK. TROPICAL STORM DORIAN IS FORECAST TO BECOME A
REMNANT LOW AND THE REMNANTS SHOULD PASS TO THE SOUTH OF SOUTH
FLORIDA ON WEDNESDAY AND THURSDAY. THE SUBTROPICAL RIDGE IS
FORECAST TO SHIFT SLIGHTLY TO THE EAST TOWARDS THE END OF THE WEEK
AS AN UPPER LEVEL TROUGH PUSHES TOWARDS THE EAST COAST AND INTO
THE WESTERN ATLANTIC. RAIN CHANCES MAY THEN INCREASE AGAIN FOR THE
EAST COAST.
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS SOUTH FLORIDA
THROUGH THE AFTERNOON AND EVENING HOURS. THERE WILL BE SOME MVFR
CONDITIONS ACROSS THE EAST COAST TERMINALS DUE TO THE SHOWER AND
THUNDERSTORM ACTIVITY THIS AFTERNOON. WINDS WILL BE SOUTH SOUTHEASTERLY
BETWEEN 5 AND 10 KNOTS BEFORE DIMINISHING LATER THIS EVENING. AT
KAPF, A WEST COAST SEA BREEZE WILL BRING WEST SOUTHWESTERLY WINDS
NEAR 10 KNOTS BEFORE DIMINISHING THIS EVENING.
&&
.MARINE...
WIND AND SEAS WILL REMAIN BELOW CRITICAL LEVELS THROUGH THE PERIOD
OUTSIDE ANY SHOWER OR THUNDERSTORM ACTIVITY WHERE LOCALLY HIGHER
WINDS AND/OR SEAS SHOULD BE EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 88 77 89 / 40 50 20 20
FORT LAUDERDALE 76 88 79 89 / 30 50 20 20
MIAMI 76 88 77 90 / 30 50 20 20
NAPLES 77 90 75 92 / 20 20 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1041 PM EDT SUN JUL 28 2013
.UPDATE...
ONLY A FEW SHOWERS REMAIN FROM AHN TO CORDELE AND THESE ARE ON THE
DYING TREND. BY 06Z IT SHOULD BE DRY ACROSS THE CWA. MADE MINOR
ADJUSTMENTS TO THE POPS. NO OTHER CHANGES PLANNED.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
WEAK FRONTAL BOUNDARY DRAPED ACROSS THE CENTRAL CWFA THIS AFTERNOON.
LOW PRESSURE AND A WARM FRONT ARE SITUATED ACROSS THE FLORIDA
PANHANDLE. ISO/SCT CONVECTION HAS DEVELOPED AHEAD OF THE WAVE OF LOW
PRESSURE DOWN SOUTH. THIS ACTIVITY SHOULD AFFECT MAINLY AREAS ALONG
THE SOUTHERN CWFA BORDER. ISOLD SHRA HAVE DEVELOPED ACROSS NORTHEAST
GA IN THE HIGHER TERRAIN. WILL HAVE TO WATCH THE SHRA/TSRA IN THE SW
CORNER OF THE CWFA...MAY HAVE TO UP THE POPS TO LIKELY IF THE
ACTIVITY KEEPS SPREADING.
LATEST RUN OF THE HRRR DOESN`T DO MUCH WITH THE CONVECTION UP
NORTH...BUT KEEPS THE SOUTHERN ACTIVITY GOING UNTIL AROUND SUNSET.
THE POTENTIAL FOR SEVERE REMAINS LOW...BUT ANY THUNDERSTORM THAT
DEVELOPS WILL HAVE THE POTENTIAL TO PRODUCE LIGHTNING STRIKES AND
GUSTY WINDS.
HRRR DIMINISHES CONVECTION AFTER SUNSET AND KEEPS THE NIGHTTIME
MOSTLY DRY. SOME PATCHY FOG IS POSSIBLE...WITH THE SATURATED GROUND
AND COOLER OVERNIGHT LOWS.
WEAK...MOSTLY DIFFUSE...FRONTAL BOUNDARY REMAINS ACROSS THE SOUTHERN
CWFA TOMORROW. DRIER AIR DOES SETTLE ON THE NORTHERN SIDE OF THE
BOUNDARY. HOWEVER...SLIGHTLY HIGHER DEWPOINTS WILL REMAIN ACROSS THE
SOUTH. MOISTURE WILL CONTINUE TO POOL ALONG THE WEAK BOUNDARY...BUT
WITH WEAK FORCING AND MARGINAL INSTABILITY...CONVECTION IS EXPECTED
TO BE LIMITED AGAIN TOMORROW.
NLISTEMAA
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
ADDED SLIGHT CHANCE POPS IN PORTIONS OF THE NORTH TUESDAY DUE TO
OROGRAPHIC ENHANCEMENT WITH RELATIVELY LIGHT WINDS WITH ANY LOW
LEVEL MOISTURE. HAVE MADE OTHER MINOR ADJUSTMENTS TO TEMPS BASED
ON LATEST BLEND OF GUIDANCE...OTHERWISE FORECAST LOOKS TO BE ON
TRACK AND PREVIOUS DISCUSSION FOLLOWS...
BAKER
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 359 AM EDT SUN JUL 28 2013/
LARGE SCALE PATTERN NOT FCST TO CHANGE MUCH DURING THE LONG TERM
PERIOD. UNUSUALLY ACTIVE WESTERLIES ACROSS THE CONUS WITH LONG
WAVE TROUGHING OVER THE EAST WILL CONTINUE. AFTER A BRIEF DRY
PERIOD WITH RISING HEIGHTS IN THE MID LEVELS...APPEARS THAT
WESTERLIES WILL DROP BACK DOWN INTO THE SE BY WED MORNING
CONTINUING THRU AT LEAST THUR NIGHT. BACK TO THE RAIN WE GO. BEST
CHC APPEARS TO BE WED AFT THRU THURS AFT. HEIGHTS PROGGED TO RISE
AGAIN ON FRI BUT THE WESTERLIES WILL BE JUST TO OUR NORTH.
GFS/ECMWF SHOW A COLD FRONT JUST TO OUR NORTH IN TN. MOISTURE FROM
REMNANTS OF DORIAN ALSO PROGGED BY LATE FRI AND SAT TO PUSH NORTH
INTO THE EASTERN GULF AND NRN FL AND MUCH OF GA.
ALL THIS SAID...NOT SEEING ANY SIGN OF SIGNIFICANT HEAVY RAIN OR SVR
WX. PW VALUES HIGH BUT NOT ANYTHING UNUSUALLY HIGH FOR THIS TIME OF
YEAR WITH VALUES AROUND 1.5 IN TUE/WED INCREASING TO 1.5-2.0 IN
THUR/FRI/SAT. SFC DEWPOINTS GREATER THAN 70 AND MLCAPE GREATER THAN
800 J/KG FCST TO REMAIN CONFINED TO SE COUNTIES THRU THURS THEN
SPREADING AREA WIDE FRI. COULD SEE SIGNIFICANT INSTABILITY BY NEXT
WEEKEND BASED ON 00Z GFS.
SNELSON
&&
.AVIATION...
00Z UPDATE...
SCATTERED SHOWERS FROM PDK TO JUST WEST OF AHN CONTINUING TO MOVE
EAST...PULLING AWAY FROM ATL BUT SHOULD THROUGH AHN THRU 02Z. OTHER
SHOWERS BETWEEN CSG AND MCN ALSO MOVING EAST. WILL NEED TO KEEP VCSH
FOR MCN AND CSG FOR THE NEXT COUPLE OF HOURS. PRECIP SHOULD
DISSIPATE BY 02Z WITH LACK OF DAYTIME HEATING. SCATTERED CIRRUS
TONIGHT WITH A CU FIELD DEVELOPING AROUND NOON MONDAY AROUND 3500 TO
4500 FT.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON FEW025 FORMING LATE TONIGHT.
HIGH CONFIDENCE ON REMAINING ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 89 68 90 / 20 10 10 20
ATLANTA 69 87 68 88 / 20 10 10 20
BLAIRSVILLE 59 82 61 84 / 10 10 5 20
CARTERSVILLE 64 87 61 89 / 10 10 5 10
COLUMBUS 72 92 72 92 / 20 20 10 20
GAINESVILLE 66 87 68 86 / 20 10 5 20
MACON 71 91 69 91 / 30 20 20 20
ROME 63 87 61 89 / 10 10 5 10
PEACHTREE CITY 67 88 62 89 / 20 10 10 20
VIDALIA 73 91 73 90 / 30 30 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....SNELSON/BAKER
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
729 PM EDT SUN JUL 28 2013
.SHORT TERM /TONIGHT THROUGH MONDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
WEAK FRONTAL BOUNDARY DRAPED ACROSS THE CENTRAL CWFA THIS AFTERNOON.
LOW PRESSURE AND A WARM FRONT ARE SITUATED ACROSS THE FLORIDA
PANHANDLE. ISO/SCT CONVECTION HAS DEVELOPED AHEAD OF THE WAVE OF LOW
PRESSURE DOWN SOUTH. THIS ACTIVITY SHOULD AFFECT MAINLY AREAS ALONG
THE SOUTHERN CWFA BORDER. ISOLD SHRA HAVE DEVELOPED ACROSS NORTHEAST
GA IN THE HIGHER TERRAIN. WILL HAVE TO WATCH THE SHRA/TSRA IN THE SW
CORNER OF THE CWFA...MAY HAVE TO UP THE POPS TO LIKELY IF THE
ACTIVITY KEEPS SPREADING.
LATEST RUN OF THE HRRR DOESN`T DO MUCH WITH THE CONVECTION UP
NORTH...BUT KEEPS THE SOUTHERN ACTIVITY GOING UNTIL AROUND SUNSET.
THE POTENTIAL FOR SEVERE REMAINS LOW...BUT ANY THUNDERSTORM THAT
DEVELOPS WILL HAVE THE POTENTIAL TO PRODUCE LIGHTNING STRIKES AND
GUSTY WINDS.
HRRR DIMINISHES CONVECTION AFTER SUNSET AND KEEPS THE NIGHTTIME
MOSTLY DRY. SOME PATCHY FOG IS POSSIBLE...WITH THE SATURATED GROUND
AND COOLER OVERNIGHT LOWS.
WEAK...MOSTLY DIFFUSE...FRONTAL BOUNDARY REMAINS ACROSS THE SOUTHERN
CWFA TOMORROW. DRIER AIR DOES SETTLE ON THE NORTHERN SIDE OF THE
BOUNDARY. HOWEVER...SLIGHTLY HIGHER DEWPOINTS WILL REMAIN ACROSS THE
SOUTH. MOISTURE WILL CONTINUE TO POOL ALONG THE WEAK BOUNDARY...BUT
WITH WEAK FORCING AND MARGINAL INSTABILITY...CONVECTION IS EXPECTED
TO BE LIMITED AGAIN TOMORROW.
NLISTEMAA
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
ADDED SLIGHT CHANCE POPS IN PORTIONS OF THE NORTH TUESDAY DUE TO
OROGRAPHIC ENHANCEMENT WITH RELATIVELY LIGHT WINDS WITH ANY LOW
LEVEL MOISTURE. HAVE MADE OTHER MINOR ADJUSTMENTS TO TEMPS BASED
ON LATEST BLEND OF GUIDANCE...OTHERWISE FORECAST LOOKS TO BE ON
TRACK AND PREVIOUS DISCUSSION FOLLOWS...
BAKER
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 359 AM EDT SUN JUL 28 2013/
LARGE SCALE PATTERN NOT FCST TO CHANGE MUCH DURING THE LONG TERM
PERIOD. UNUSUALLY ACTIVE WESTERLIES ACROSS THE CONUS WITH LONG
WAVE TROUGHING OVER THE EAST WILL CONTINUE. AFTER A BRIEF DRY
PERIOD WITH RISING HEIGHTS IN THE MID LEVELS...APPEARS THAT
WESTERLIES WILL DROP BACK DOWN INTO THE SE BY WED MORNING
CONTINUING THRU AT LEAST THUR NIGHT. BACK TO THE RAIN WE GO. BEST
CHC APPEARS TO BE WED AFT THRU THURS AFT. HEIGHTS PROGGED TO RISE
AGAIN ON FRI BUT THE WESTERLIES WILL BE JUST TO OUR NORTH.
GFS/ECMWF SHOW A COLD FRONT JUST TO OUR NORTH IN TN. MOISTURE FROM
REMNANTS OF DORIAN ALSO PROGGED BY LATE FRI AND SAT TO PUSH NORTH
INTO THE EASTERN GULF AND NRN FL AND MUCH OF GA.
ALL THIS SAID...NOT SEEING ANY SIGN OF SIGNIFICANT HEAVY RAIN OR SVR
WX. PW VALUES HIGH BUT NOT ANYTHING UNUSUALLY HIGH FOR THIS TIME OF
YEAR WITH VALUES AROUND 1.5 IN TUE/WED INCREASING TO 1.5-2.0 IN
THUR/FRI/SAT. SFC DEWPOINTS GREATER THAN 70 AND MLCAPE GREATER THAN
800 J/KG FCST TO REMAIN CONFINED TO SE COUNTIES THRU THURS THEN
SPREADING AREA WIDE FRI. COULD SEE SIGNIFICANT INSTABILITY BY NEXT
WEEKEND BASED ON 00Z GFS.
SNELSON
&&
.AVIATION...
00Z UPDATE...
SCATTERED SHOWERS FROM PDK TO JUST WEST OF AHN CONTINUING TO MOVE
EAST...PULLING AWAY FROM ATL BUT SHOULD THROUGH AHN THRU 02Z. OTHER
SHOWERS BETWEEN CSG AND MCN ALSO MOVING EAST. WILL NEED TO KEEP VCSH
FOR MCN AND CSG FOR THE NEXT COUPLE OF HOURS. PRECIP SHOULD
DISSIPATE BY 02Z WITH LACK OF DAYTIME HEATING. SCATTERED CIRRUS
TONIGHT WITH A CU FIELD DEVELOPING AROUND NOON MONDAY AROUND 3500 TO
4500 FT.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON FEW025 FORMING LATE TONIGHT.
HIGH CONFIDENCE ON REMAINING ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 89 68 90 / 20 10 10 20
ATLANTA 69 87 68 88 / 20 10 10 20
BLAIRSVILLE 59 82 61 84 / 10 10 5 20
CARTERSVILLE 64 87 61 89 / 10 10 5 10
COLUMBUS 72 92 72 92 / 20 20 10 20
GAINESVILLE 66 87 68 86 / 20 10 5 20
MACON 71 91 69 91 / 30 20 20 20
ROME 63 87 61 89 / 10 10 5 10
PEACHTREE CITY 67 88 62 89 / 20 10 10 20
VIDALIA 73 91 73 90 / 30 30 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....SNELSON/BAKER
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
132 PM EDT SAT JUL 27 2013
.PREV DISCUSSION... /ISSUED 1025 AM EDT SAT JUL 27 2013/
UPDATE...
WEAK FRONTAL BOUNDARY SITUATED ACROSS THE MID MISSISSIPPI RIVER
VALLEY THIS MORNING. 500MB ANALYSIS SHOWS A SHEAR AXIS ACROSS
WESTERN GA. A BROKEN LINE OF SHOWERS HAS FORMED ALONG AND JUST
AHEAD OF THIS FEATURE. THE LATEST RUNS OF THE HRRR SEEM TO HANDLE
THIS WELL...SO HAVE RE-ORIENTED POPS ACCORDINGLY.
IN ADDITION...DUE TO THE THICK CLOUD COVER AND PRECIP...HAVE DECREASED
MAX TEMPS ACROSS THE NORTHERN PART OF THE STATE A FEW DEGREES.
PREV DISCUSSION... /ISSUED 748 AM EDT SAT JUL 27 2013/
PREV DISCUSSION... /ISSUED 434 AM EDT SAT JUL 27 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...
PRIMARY CONCERN IS LIKELIHOOD OF CONVECTION THIS AFTERNOON AND
EVENING. APPROACHING SHORT WAVE TROUGH JUST WEST OF CWA THIS
MORNING YET MEAN RH AND VERTICAL MOTION LACKING. IR/WV IMAGERY
ALSO CONFIRMING THIS BAND OF DRIER AIR CURRENTLY ACROSS WESTERN GA
UP THROUGH ERN TN. DEEPER MOISTURE JUST WEST OF TROUGH AXIS IN
MS/AL. THIS MOISTURE WILL PUSH INTO CWA THIS AFTERNOON AND EVENING
SO EXPECT DEVELOPMENT OF SCT TSRA AROUND 18-20Z WITH 30-50PCT
COVERAGE...GREATEST OVER ERN AND WC/SW GA. A FEW STORMS COULD
APPROACH SVR CRITERIA BUT MLCAPE AND THETA-E LAPSE RATES DO NOT
WARRANT ANYTHING MORE INTENSE THAN THAT. OVER NORTH AND MUCH OF
MIDDLE GA...GFS HAS VERY LITTLE CAPE DUE TO SLIGHTLY DRIER LOW
LEVELS AND THICKER MID CLOUDS. AFTER SOME PATCHY FOG AGAIN SUNDAY
MORNING...SHOULD BE EVEN LESS COVERAGE OF STORMS OVER NORTH AND
WEST GA SUNDAY PM AS SHORT WAVE PASSES AND DRIER AIR PUSHES
FURTHER IN. HAVE KEPT POPS IN CHC CATEGORY OVER SOUTH AND EAST
COUNTIES BUT MUCH OF NORTH GA WILL BE POP-FREE.
WENT ABOVE MAX TEMP GUIDANCE FOR SAT AND SUN BASED ON LESS CLOUDS/
PRECIP THAN PREV THOUGHT. USED BLEND OF 30 DAY BIAS CORRECTED TEMPS
WITH GREATER WEIGHT TOWARD THE MAV FOR MIN TEMPS.
SNELSON
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
WITH SFC RIDGING BUILDING INTO THE CWA NEAR THE BEGINNING OF THE
LONG TERM AND NO STRONG WAVES PEGGED IN THE UPPER LEVELS...THIS MAY
PROVIDE A SHORT BREAK IN THE HIGHER THAN CLIMO POPS. WITH SFC RIDGE
CENTERED OVER THE OHIO VALLEY ON MONDAY...THE GFS KEEPS THE CWA DRY
WHEREAS THE ECMWF LINGERS SOME BETTER MOISTURE ACROSS CENTRAL
GEORGIA. FORECAST IS NEAR A BLEND OF THE TWO...WITH ONLY A SLIGHT
CHANCE MENTIONED ACROSS CENTRAL GEORGIA FOR THE AFTERNOON. WITH A
SERIES OF SHORTWAVES MOVING THROUGH MID-WEEK...WILL SEE A RETURN
OF THE ABOVE NORMAL POPS. GFS HAS BEEN FAIRLY CONSISTENT WITH
TIMING BETWEEN LAST NIGHT AND TONIGHT WHEREAS THE ECMWF HAS HAD
SOME RUN TO RUN DIFFERENCES. 00Z ECMWF HAS COME INTO BETTER
AGREEMENT AGAIN WITH THE 00Z GFS AS OPPOSED TO THE 12Z ECMWF. MAIN
IMPACT WITH THESE SHORTWAVES WILL BE AN INCREASE IN POPS FOR THE
WEDNESDAY TO THURSDAY TIME FRAME WITH THE BEST CHANCES ACROSS
NORTH GEORGIA ON WEDNESDAY. GIVEN SOME CONSISTENCY IN TIMING WITH
THE GFS...HAVE GONE AHEAD AND INTRODUCED LIKELY POPS FOR FAR NORTH
GEORGIA ON WEDNESDAY. PLENTY OF INSTABILITY WITH THE SYSTEM...BUT
SHEAR IS LACKING. STILL WITH INSTABILITY ALONE...ITS ENOUGH THAT
SOME OF THE STORMS COULD BECOME STRONG. GFS AND ECMWF ARE
CONSISTENT WITH HIGHER RAINFALL AMOUNTS ACROSS NORTH GEORGIA WITH
BOTH MODELS DEPICTING JUST UNDER 2 INCHES IN THE WEDNESDAY/THURSDAY
TIME FRAME. BY FRIDAY...UPPER DISTURBANCE IS EAST OF THE AREA AND
THAT WILL BRING US BACK INTO A MORE TYPICAL SUMMERTIME
PATTERN...AT LEAST IN TERMS OF CONVECTION.
11
&&
.AVIATION...
18Z UPDATE...
LIGHT SHOWERS ARE APPROACHING THE AIRPORT AT ISSUANCE TIME.
HOWEVER...ANY PRECIP FALLING IS VERY LIGHT IN NATURE AND BARELY
MEASURING. DO THINK THE CHANCES FOR THUNDER INCREASE A LITTLE BIT
DURING THE MID AFTERNOON...BUT INSTABILITY IS LIMITED AND ANY
THUNDERSTORMS THAT DEVELOP WILL BE ISOLATED. MODELS ARE FORECASTING
LOW CIGS AGAIN TONIGHT. CIGS COULD REACH 006 AT ATL FOR A BRIEF
PERIOD OF TIME. FROPA TOMORROW WITH A WIND SHIFT TO THE W/NW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 85 69 88 65 / 50 30 20 10
ATLANTA 83 69 86 66 / 40 30 20 10
BLAIRSVILLE 77 63 82 57 / 40 30 10 10
CARTERSVILLE 83 66 86 60 / 40 30 10 10
COLUMBUS 88 72 89 70 / 40 30 30 20
GAINESVILLE 82 68 85 64 / 40 30 20 10
MACON 88 69 90 69 / 50 30 40 20
ROME 84 66 86 59 / 30 30 10 10
PEACHTREE CITY 85 67 86 62 / 40 30 20 10
VIDALIA 88 72 89 72 / 50 30 40 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1025 AM EDT SAT JUL 27 2013
.UPDATE...
WEAK FRONTAL BOUNDARY SITUATED ACROSS THE MID MISSISSIPPI RIVER
VALLEY THIS MORNING. 500MB ANALYSIS SHOWS A SHEAR AXIS ACROSS
WESTERN GA. A BROKEN LINE OF SHOWERS HAS FORMED ALONG AND JUST
AHEAD OF THIS FEATURE. THE LATEST RUNS OF THE HRRR SEEM TO HANDLE
THIS WELL...SO HAVE RE-ORIENTED POPS ACCORDINGLY.
IN ADDITION...DUE TO THE THICK CLOUD COVER AND PRECIP...HAVE DECREASED
MAX TEMPS ACROSS THE NORTHERN PART OF THE STATE A FEW DEGREES.
&&
.PREV DISCUSSION... /ISSUED 748 AM EDT SAT JUL 27 2013/
PREV DISCUSSION... /ISSUED 434 AM EDT SAT JUL 27 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...
PRIMARY CONCERN IS LIKELIHOOD OF CONVECTION THIS AFTERNOON AND
EVENING. APPROACHING SHORT WAVE TROUGH JUST WEST OF CWA THIS
MORNING YET MEAN RH AND VERTICAL MOTION LACKING. IR/WV IMAGERY
ALSO CONFIRMING THIS BAND OF DRIER AIR CURRENTLY ACROSS WESTERN GA
UP THROUGH ERN TN. DEEPER MOISTURE JUST WEST OF TROUGH AXIS IN
MS/AL. THIS MOISTURE WILL PUSH INTO CWA THIS AFTERNOON AND EVENING
SO EXPECT DEVELOPMENT OF SCT TSRA AROUND 18-20Z WITH 30-50PCT
COVERAGE...GREATEST OVER ERN AND WC/SW GA. A FEW STORMS COULD
APPROACH SVR CRITERIA BUT MLCAPE AND THETA-E LAPSE RATES DO NOT
WARRANT ANYTHING MORE INTENSE THAN THAT. OVER NORTH AND MUCH OF
MIDDLE GA...GFS HAS VERY LITTLE CAPE DUE TO SLIGHTLY DRIER LOW
LEVELS AND THICKER MID CLOUDS. AFTER SOME PATCHY FOG AGAIN SUNDAY
MORNING...SHOULD BE EVEN LESS COVERAGE OF STORMS OVER NORTH AND
WEST GA SUNDAY PM AS SHORT WAVE PASSES AND DRIER AIR PUSHES
FURTHER IN. HAVE KEPT POPS IN CHC CATEGORY OVER SOUTH AND EAST
COUNTIES BUT MUCH OF NORTH GA WILL BE POP-FREE.
WENT ABOVE MAX TEMP GUIDANCE FOR SAT AND SUN BASED ON LESS CLOUDS/
PRECIP THAN PREV THOUGHT. USED BLEND OF 30 DAY BIAS CORRECTED TEMPS
WITH GREATER WEIGHT TOWARD THE MAV FOR MIN TEMPS.
SNELSON
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
WITH SFC RIDGING BUILDING INTO THE CWA NEAR THE BEGINNING OF THE
LONG TERM AND NO STRONG WAVES PEGGED IN THE UPPER LEVELS...THIS MAY
PROVIDE A SHORT BREAK IN THE HIGHER THAN CLIMO POPS. WITH SFC RIDGE
CENTERED OVER THE OHIO VALLEY ON MONDAY...THE GFS KEEPS THE CWA DRY
WHEREAS THE ECMWF LINGERS SOME BETTER MOISTURE ACROSS CENTRAL
GEORGIA. FORECAST IS NEAR A BLEND OF THE TWO...WITH ONLY A SLIGHT
CHANCE MENTIONED ACROSS CENTRAL GEORGIA FOR THE AFTERNOON. WITH A
SERIES OF SHORTWAVES MOVING THROUGH MID-WEEK...WILL SEE A RETURN
OF THE ABOVE NORMAL POPS. GFS HAS BEEN FAIRLY CONSISTENT WITH
TIMING BETWEEN LAST NIGHT AND TONIGHT WHEREAS THE ECMWF HAS HAD
SOME RUN TO RUN DIFFERENCES. 00Z ECMWF HAS COME INTO BETTER
AGREEMENT AGAIN WITH THE 00Z GFS AS OPPOSED TO THE 12Z ECMWF. MAIN
IMPACT WITH THESE SHORTWAVES WILL BE AN INCREASE IN POPS FOR THE
WEDNESDAY TO THURSDAY TIME FRAME WITH THE BEST CHANCES ACROSS
NORTH GEORGIA ON WEDNESDAY. GIVEN SOME CONSISTENCY IN TIMING WITH
THE GFS...HAVE GONE AHEAD AND INTRODUCED LIKELY POPS FOR FAR NORTH
GEORGIA ON WEDNESDAY. PLENTY OF INSTABILITY WITH THE SYSTEM...BUT
SHEAR IS LACKING. STILL WITH INSTABILITY ALONE...ITS ENOUGH THAT
SOME OF THE STORMS COULD BECOME STRONG. GFS AND ECMWF ARE
CONSISTENT WITH HIGHER RAINFALL AMOUNTS ACROSS NORTH GEORGIA WITH
BOTH MODELS DEPICTING JUST UNDER 2 INCHES IN THE WEDNESDAY/THURSDAY
TIME FRAME. BY FRIDAY...UPPER DISTURBANCE IS EAST OF THE AREA AND
THAT WILL BRING US BACK INTO A MORE TYPICAL SUMMERTIME
PATTERN...AT LEAST IN TERMS OF CONVECTION.
11
AVIATION...
12Z UPDATE...
IFR VSBYS AND CIGS SHOULD BE CLEARING BY 13-14Z. OTHERWISE...PRIMARY
CONCERN IS CHC FOR TSRA THIS AFTERNOON/EVENING. SEEING SOME SIGNS
THAT COVERAGE WILL NOT BE AS WIDESPREAD ACROSS MOST OF THE AREA AS
THOUGHT EARLIER. HAVE INCREASED POP TO TEMPO FROM 20Z-00Z FOR
MOST SITES BUT LATER FORECASTS MAY NEED TO DECREASE DURATION OF
TEMPO OR REMOVE IT ALL TOGETHER. SE SFC WINDS WILL SHIFT TO SW
13-15Z WITH SPEEDS INCREASING TO 6-8KTS. ALREADY SEEING SSW WINDS
AT ATL. IN SPITE OF DRIER AIR MOVING INTO NORTH GA EARLY SUNDAY
MORNING...WILL LIKELY SEE SOME STRATUS AGAIN.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TSRA LIKELIHOOD/COVERAGE THIS AFTERNOON.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 87 69 88 65 / 50 40 20 10
ATLANTA 85 69 86 66 / 40 30 20 10
BLAIRSVILLE 81 63 82 57 / 50 30 10 10
CARTERSVILLE 85 66 86 60 / 40 30 10 10
COLUMBUS 89 72 89 70 / 40 40 20 20
GAINESVILLE 84 68 85 64 / 50 30 20 10
MACON 90 69 90 69 / 40 40 30 20
ROME 86 66 86 59 / 40 30 10 10
PEACHTREE CITY 85 67 86 62 / 30 30 20 10
VIDALIA 90 72 89 72 / 40 40 40 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LISTEMAA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1232 PM CDT SAT JUL 27 2013
.DISCUSSION...
ISSUED 1033 AM CDT SAT JUL 27 2013
UNSEASONABLY COOL AIRMASS HAS SETTLED INTO CENTRAL ILLINOIS THIS
MORNING...WITH 15Z/10AM TEMPS RANGING FROM THE LOWER 60S NORTH OF
PEORIA TO THE LOWER 70S ALONG/SOUTH OF I-70. SKIES STARTED OUT
CLEAR...BUT HAVE BECOME PARTLY SUNNY AS SCT-BKN DIURNAL CU HAVE
DEVELOPED ACROSS THE AREA. VERY COLD TEMPS ALOFT ASSOCIATED WITH
DEEP UPPER LOW SPINNING OVER THE WESTERN GREAT LAKES WILL SUPPORT
STEEP MID-LEVEL LAPSE RATES AND PLENTY OF CLOUD DEVELOPMENT. MAY
EVEN SEE SOME SPRINKLES FROM TIME TO TIME...AS FORECAST SOUNDINGS
SHOW A 3000 TO 4000-FOOT THICK CLOUD LAYER ENHANCED BY A SHORT-WAVE
TROUGH ROTATING ACROSS NORTH-CENTRAL ILLINOIS. HRRR SUGGESTS
SCATTERED SPRINKLES AHEAD OF THIS FEATURE AS WELL...AND HAVE SEEN
SOME WEAK RETURNS UPSTREAM ON KDVN RADAR OVER THE PAST HOUR.
HAVE THEREFORE UPDATED THE FORECAST TO INCREASE CLOUD COVER AND
ADD SCATTERED SPRINKLES DURING THE LATE MORNING INTO THE
AFTERNOON. ALSO NUDGED HIGHS UP A DEGREE OR TWO...AS JULY SUN HAS
WARMED READINGS A BIT FASTER THIS MORNING THAN PREVIOUSLY THOUGHT.
ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 1232 PM CDT SAT JUL 27 2013
AFTER A PERIOD OF MVFR CEILINGS THIS MORNING...CLOUD BASES HAVE
GRADUALLY RISEN INTO THE VFR CATEGORY EARLY THIS AFTERNOON.
FORECAST SOUNDINGS SUGGEST THIS WILL CONTINUE THROUGH THE BALANCE
OF THE AFTERNOON BEFORE DIURNAL CLOUD COVER DISSIPATES TOWARD
SUNSET. BASED ON LATEST SATELLITE IMAGERY...IT APPEARS THE
THICKEST CLOUD COVER IS CURRENTLY LOCATED OVER EASTERN IOWA INTO
NORTHERN ILLINOIS. AS A RESULT...WILL MAINTAIN BROKEN VFR CEILINGS
AT BOTH KPIA AND KBMI UNTIL 01Z. FURTHER SOUTH/EAST...WILL SCATTER
CLOUDS OUT A BIT EARLIER AT 23Z. AN AREA OF CLOUDS OVER EASTERN
MINNESOTA INTO WISCONSIN WILL CONTINUE TO DROP S/SE TONIGHT. MODEL
RH PROFILES SUGGEST MUCH OF THIS WILL REMAIN JUST N/NE OF THE KILX
CWA...HOWEVER WILL INCLUDE SCT CLOUD COVER THROUGH THE ENTIRE NIGHT
AS FAR SOUTH AS KPIA AND KBMI AS THIS MOISTURE GRAZES THE AREA.
ELSEWHERE...CLEAR SKIES WILL PREVAIL AFTER SUNSET. NORTHWESTERLY
WINDS WILL INITIALLY GUST TO BETWEEN 15 AND 20KT AT TIMES THIS
AFTERNOON...THEN WILL BACK TO WESTERLY AND DECREASE TO AROUND 5KT
TONIGHT.
BARNES
&&
.PREV DISCUSSION...
ISSUED 303 AM CDT SAT JUL 27 2013
SHORT TERM...TODAY THROUGH MONDAY
COLD FRONT AT 07Z HAD CLEARED ALL BUT OUR SOUTHEAST FEW COUNTIES
WHILE SKIES CLEARED FOR MUCH OF THE CWA. LIGHT W/NW WINDS WERE
SLOWLY BRINGING IN COOLER AND DRIER AIR WITH MID 50S DEW POINTS
NOTED WEST OF THE IL RIVER. UNSEASONABLY COLD AIRMASS POISED TO
OUR NORTHWEST...WITH A FALL-LIKE +2C 850MB 00Z TEMPERATURE AT
INTERNATIONAL FALLS. THIS MODIFIED CANADIAN AIRMASS WILL SHIFT
SOUTHEAST ACROSS THE REGION THIS WEEKEND ON THE BACK SIDE OF A
STRONG CLOSED 500MB LOW DRIFTING ACROSS THE GREAT LAKES. STEEP LOW
LEVEL LAPSE RATES AND CYCLONIC FLOW SHOULD ALLOW PLENTY OF DIURNAL
CU FORMATION TODAY AND SUNDAY. WITH DEEPER MOISTURE STAYING
FARTHER NORTHEAST FEEL ANY SPRINKLES WILL BE TOO ISOLATED TO
MENTION IN FORECAST. MAIN STORY THROUGH SUNDAY WILL BE UNUSUALLY
COOL TEMPERATURES FOR LATE JULY. 850MB READINGS ARE FORECAST TO DIP AS
LOW AS +5-7C OVER THE NORTHERN CWA LATER TODAY AND TONIGHT. THUS
RECORD COOL HIGHS TODAY /GENERALLY LOWER 70S/ AND RECORD LOWS
TONIGHT /NEAR 50F/ WILL BE IN JEOPARDY. SEE CLIMATE SECTION BELOW
FOR SPECIFIC NUMBERS FOR OFFICIAL CLIMATE SITES.
TEMPERATURES WILL BEGIN TO MODERATE LATER SUNDAY AND ESPECIALLY
MONDAY AS HIGH PRESSURE SHIFTS SOUTH OF THE OHIO VALLEY AND THE
NEXT LOW DEVELOPS OVER THE CENTRAL PLAINS. A WARM FRONT LIFTING
NORTHEAST ACROSS MISSOURI COULD SPREAD SCATTERED THUNDERSTORMS AS
FAR EAST AS WESTERN IL LATE MONDAY AFTERNOON WITH BETTER CHANCES
MONDAY NIGHT.
LONG TERM...TUESDAY THROUGH FRIDAY
00Z MODELS HAVE COME INTO A BIT BETTER AGREEMENT IN HANDLING THE CENTRAL
PLAINS LOW WHICH IS FORECAST TO TRACK EAST TOWARDS THE CENTRAL
MISSISSIPPI RIVER/LOWER OHIO RIVER VALLEY REGION BY LATE TUESDAY.
NAM IS FARTHEST NORTH/QUICKEST WHILE ECMWF HAS TRENDED FARTHER
NORTH AND NOW LOOKS SIMILAR TO CURRENT AND PREVIOUS GFS SOLUTIONS.
THUS WILL EXPAND LIKELY POPS NORTH FOR MUCH OF THE SOUTHERN HALF
OF THE CWA MONDAY NIGHT AND TUESDAY WITH CHANCE POPS FARTHER NORTH.
MOISTURE RETURN SOUTH OF THE SYSTEM AND FORCING SUGGEST A MODERATE
1-2 INCH QPF EVENT WHERE EVENTUAL PRECIP PATH DOES LAY OUT.
WED-FRI APPEARS GENERALLY DRY WITH LOW AMPLITUDE NW FLOW ALOFT AND
TEMPERATURES RETURNING TO NEAR NORMAL. A WEAK UPPER WAVE IS
PROGGED TO MOVE THROUGH IN THE WED/WED NIGHT TIME FRAME BUT WITH
LIMITED FORCING THIS FAR SOUTH ONLY HAVE SLIGHT CHANCE POPS. A
MORE RESPECTABLE SYSTEM MAY PUSH EAST INTO THE MIDWEST TOWARDS THE
END OF THE WEEK. QUITE A LARGE MODEL SPREAD IN TIMING AND LOCATION
SO CURRENT LOW CHANCE POPS ON FRIDAY LOOK GOOD.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1033 AM CDT SAT JUL 27 2013
.DISCUSSION...
ISSUED 1033 AM CDT SAT JUL 27 2013
UNSEASONABLY COOL AIRMASS HAS SETTLED INTO CENTRAL ILLINOIS THIS
MORNING...WITH 15Z/10AM TEMPS RANGING FROM THE LOWER 60S NORTH OF
PEORIA TO THE LOWER 70S ALONG/SOUTH OF I-70. SKIES STARTED OUT
CLEAR...BUT HAVE BECOME PARTLY SUNNY AS SCT-BKN DIURNAL CU HAVE
DEVELOPED ACROSS THE AREA. VERY COLD TEMPS ALOFT ASSOCIATED WITH
DEEP UPPER LOW SPINNING OVER THE WESTERN GREAT LAKES WILL SUPPORT
STEEP MID-LEVEL LAPSE RATES AND PLENTY OF CLOUD DEVELOPMENT. MAY
EVEN SEE SOME SPRINKLES FROM TIME TO TIME...AS FORECAST SOUNDINGS
SHOW A 3000 TO 4000-FOOT THICK CLOUD LAYER ENHANCED BY A SHORT-WAVE
TROUGH ROTATING ACROSS NORTH-CENTRAL ILLINOIS. HRRR SUGGESTS
SCATTERED SPRINKLES AHEAD OF THIS FEATURE AS WELL...AND HAVE SEEN
SOME WEAK RETURNS UPSTREAM ON KDVN RADAR OVER THE PAST HOUR.
HAVE THEREFORE UPDATED THE FORECAST TO INCREASE CLOUD COVER AND
ADD SCATTERED SPRINKLES DURING THE LATE MORNING INTO THE
AFTERNOON. ALSO NUDGED HIGHS UP A DEGREE OR TWO...AS JULY SUN HAS
WARMED READINGS A BIT FASTER THIS MORNING THAN PREVIOUSLY THOUGHT.
ZONE UPDATE HAS ALREADY BEEN ISSUED.
BARNES
&&
.AVIATION...
ISSUED 608 AM CDT SAT JUL 27 2013
VFR CONDITIONS SHOULD PREVAIL AT ALL TAF SITES NEXT 24HRS. SKIES
WILL START AS CLEAR AT ALL SITES...BUT BELIEVE CU/SC WILL DEVELOP
THIS MORNING AND BE SCATTERED FOR MOST OF THE DAY. THERE COULD BE
A 3-4 HOURS WHERE THE CU/SC BECOMES BROKEN AT TIMES SO HAVE TEMPO
GROUP FOR ALL SITES FOR THE LATE MORNING TO EARLY AFTERNOON. CLOUD
COVER SHOULD BE DIURNAL SO HAVE SKIES CLEARING OUT AGAIN AROUND
SUNSET. WINDS WILL BE NORTHWEST MOST OF THE DAY BUT THEN BECOME
VARIABLE AND LIGHTER AROUND SUNSET.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 303 AM CDT SAT JUL 27 2013
SHORT TERM...TODAY THROUGH MONDAY
COLD FRONT AT 07Z HAD CLEARED ALL BUT OUR SOUTHEAST FEW COUNTIES
WHILE SKIES CLEARED FOR MUCH OF THE CWA. LIGHT W/NW WINDS WERE
SLOWLY BRINGING IN COOLER AND DRIER AIR WITH MID 50S DEW POINTS
NOTED WEST OF THE IL RIVER. UNSEASONABLY COLD AIRMASS POISED TO
OUR NORTHWEST...WITH A FALL-LIKE +2C 850MB 00Z TEMPERATURE AT
INTERNATIONAL FALLS. THIS MODIFIED CANADIAN AIRMASS WILL SHIFT
SOUTHEAST ACROSS THE REGION THIS WEEKEND ON THE BACK SIDE OF A
STRONG CLOSED 500MB LOW DRIFTING ACROSS THE GREAT LAKES. STEEP LOW
LEVEL LAPSE RATES AND CYCLONIC FLOW SHOULD ALLOW PLENTY OF DIURNAL
CU FORMATION TODAY AND SUNDAY. WITH DEEPER MOISTURE STAYING
FARTHER NORTHEAST FEEL ANY SPRINKLES WILL BE TOO ISOLATED TO
MENTION IN FORECAST. MAIN STORY THROUGH SUNDAY WILL BE UNUSUALLY
COOL TEMPERATURES FOR LATE JULY. 850MB READINGS ARE FORECAST TO DIP AS
LOW AS +5-7C OVER THE NORTHERN CWA LATER TODAY AND TONIGHT. THUS
RECORD COOL HIGHS TODAY /GENERALLY LOWER 70S/ AND RECORD LOWS
TONIGHT /NEAR 50F/ WILL BE IN JEOPARDY. SEE CLIMATE SECTION BELOW
FOR SPECIFIC NUMBERS FOR OFFICIAL CLIMATE SITES.
TEMPERATURES WILL BEGIN TO MODERATE LATER SUNDAY AND ESPECIALLY
MONDAY AS HIGH PRESSURE SHIFTS SOUTH OF THE OHIO VALLEY AND THE
NEXT LOW DEVELOPS OVER THE CENTRAL PLAINS. A WARM FRONT LIFTING
NORTHEAST ACROSS MISSOURI COULD SPREAD SCATTERED THUNDERSTORMS AS
FAR EAST AS WESTERN IL LATE MONDAY AFTERNOON WITH BETTER CHANCES
MONDAY NIGHT.
LONG TERM...TUESDAY THROUGH FRIDAY
00Z MODELS HAVE COME INTO A BIT BETTER AGREEMENT IN HANDLING THE CENTRAL
PLAINS LOW WHICH IS FORECAST TO TRACK EAST TOWARDS THE CENTRAL
MISSISSIPPI RIVER/LOWER OHIO RIVER VALLEY REGION BY LATE TUESDAY.
NAM IS FARTHEST NORTH/QUICKEST WHILE ECMWF HAS TRENDED FARTHER
NORTH AND NOW LOOKS SIMILAR TO CURRENT AND PREVIOUS GFS SOLUTIONS.
THUS WILL EXPAND LIKELY POPS NORTH FOR MUCH OF THE SOUTHERN HALF
OF THE CWA MONDAY NIGHT AND TUESDAY WITH CHANCE POPS FARTHER NORTH.
MOISTURE RETURN SOUTH OF THE SYSTEM AND FORCING SUGGEST A MODERATE
1-2 INCH QPF EVENT WHERE EVENTUAL PRECIP PATH DOES LAY OUT.
WED-FRI APPEARS GENERALLY DRY WITH LOW AMPLITUDE NW FLOW ALOFT AND
TEMPERATURES RETURNING TO NEAR NORMAL. A WEAK UPPER WAVE IS
PROGGED TO MOVE THROUGH IN THE WED/WED NIGHT TIME FRAME BUT WITH
LIMITED FORCING THIS FAR SOUTH ONLY HAVE SLIGHT CHANCE POPS. A
MORE RESPECTABLE SYSTEM MAY PUSH EAST INTO THE MIDWEST TOWARDS THE
END OF THE WEEK. QUITE A LARGE MODEL SPREAD IN TIMING AND LOCATION
SO CURRENT LOW CHANCE POPS ON FRIDAY LOOK GOOD.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1142 PM CDT FRI JUL 26 2013
.DISCUSSION...
ISSUED 834 PM CDT FRI JUL 26 2013
WEAKENING LINE OF CONVECTION HAS PROGRESSED ABOUT A THIRD OF THE
WAY ACROSS THE CWA...EXTENDING FROM LINCOLN TO WINCHESTER AT 830
PM. HAVE HAD SEVERAL REPORTS OF A QUICK HALF TO 1 INCH OF RAIN
WITH THIS BAND. FURTHER EAST...HAVE HAD SCATTERED SHOWERS MUCH OF
THE EVENING. NOT MUCH IN THE WAY OF INSTABILITY ACROSS THE EASTERN
HALF OF THE CWA...SO THE CURRENT LINE SHOULD CONTINUE TO SLOWLY
WEAKEN. HAVE UPDATED THE GRIDS ACROSS THE EAST TO MENTION ONLY
ISOLATED THUNDER WITH SCATTERED SHOWERS PREVAILING.
FRONTAL BOUNDARY WAS APPROACHING THE ILLINOIS RIVER AND SKIES
WERE QUICKLY CLEARING BEHIND IT...ALTHOUGH SOME COLD-AIR
STRATOCUMULUS CONTINUES TO DROP SOUTHWARD THROUGH IOWA. DRIER AIR
IS NOT TOO FAR BEHIND THE FRONT WITH DEW POINTS DOWN TO THE UPPER
40S IN PORTIONS OF CENTRAL IOWA. WITH THIS TYPE OF DRIER AIR
ADVECTING IN...CURRENT LOW TEMPERATURE FORECAST STILL LOOKS
REASONABLE...ALTHOUGH SOME UPDATES WERE DONE TO THE HOURLY TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 1142 PM CDT FRI JUL 26 2013
FRONTAL BOUNDARY APPROACHING KCMI AS MIDNIGHT APPROACHES...WITH
WINDS TO SWING AROUND TO THE NORTHWEST SHORTLY. REMNANTS OF THE
SHOWERS WERE SOUTH OF THE TAF SITES AND NO ADDITIONAL RAIN IS
EXPECTED. HAVING SOME ISSUES WITH MVFR CEILINGS ALONG THE
BOUNDARY...DIPPING BELOW 1000 FEET AT TIMES AROUND KCMI. BACK EDGE
OF THE CLOUDS HAS REACHED KSPI AND WILL MOVE EAST OF THE REMAINING
TAF SITES BY 11Z.
LATER IN THE DAY ON SATURDAY...SOME GUSTY WINDS TO AROUND 15 KNOTS
ARE EXPECTED AS A DEEP UPPER LOW SPINS OVER WISCONSIN AND UPPER
MICHIGAN. COLD AIR ALOFT WILL LEAD TO MORE DIURNAL CLOUD
DEVELOPMENT AROUND 4000 FEET...AND MAY YIELD A COUPLE SPRINKLES AS
WELL. HUMIDITY PLOTS SHOWING MORE SUBSTANTIAL CEILINGS TRYING TO
WORK THEIR WAY SOUTHWARD TOWARD THE TAF SITES AFTER 00Z. HAVE KEPT
EVENING CLOUDS IN THE SCATTERED CATEGORY FOR NOW...AS THE CORRIDOR
ALONG I-74 IS ON THE PERIPHERY OF THIS SLUG OF CLOUDS.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT FRI JUL 26 2013
SHOWERS AND STORMS WILL BE POSSIBLE THROUGH TONIGHT ALONG A COLD
FRONT...THEN AN UNSEASONABLY COOL AIR MASS WILL SETTLE INTO
ILLINOIS FOR SATURDAY AND SUNDAY. A WARMING TREND WILL BEGIN ON
MONDAY AS UPPER FLOW BECOMES MORE ZONAL FROM WEST TO EAST. ONE LOW
PRESSURE SYSTEM IS EXPECTED TO EJECT FROM THE SOUTHERN PLAINS
ACROSS SOUTHERN ILLINOIS MONDAY NIGHT AND TUESDAY. A WEAKER UPPER
TROUGH WILL SWING ACROSS NORTHERN ILLINOIS ON THURSDAY...SETTING
UP NORTHWEST FLOW ALOFT THROUGH FRIDAY.
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
19Z SURFACE ANALYSIS SHOWS THE COLD FRONT APPROACHING THE
IOWA/ILLINOIS BORDER. RADAR SHOWS A NARROW LINE OF SHOWERS AND
STORMS ALONG THE FRONT IN IOWA...AND FARTHER SOUTHEAST AHEAD OF
THE FRONT IN EASTERN MISSOURI AND FAR WESTERN ILLINOIS. A BROAD
COVERAGE OF LIGHT RAIN SHOWERS EXTENDED ACROSS MUCH OF CENTRAL
ILLINOIS AND INTO WEST CENTRAL INDIANA. MOST AREAS IN CENTRAL
ILLINOIS WERE SEEING LESS THAN 0.10" OF RAIN OUT AHEAD OF THE
FRONT.
4KM NCEP AND HRRR OUTPUT INDICATE THE LINE WILL MAINTAIN SOME
INTENSITY DURING THE DAYLIGHT HOURS...BUT WEAKEN WITH SUNSET AS
THE LINE OF STORMS REACHES THE I-55 CORRIDOR. TIMING BASED ON
RADAR AND HRRR HAS THE LINE OF STORMS GENERALLY INTO INDIANA BY
08Z/3 AM. THE GFS/NAM/ECMWF/GEM ARE NOT FAR OFF FROM THAT
ASSESSMENT...SO WE HAVE UPDATED THE POPS LIKEWISE. BASICALLY,
SCATTERED COVERAGE IS EXPECTED ALONG AND AHEAD OF THE FRONT, SO
CHANCE POPS WERE USED /30-50 PCT/. SOME AREAS MAY SEE A STRONGER
UPDRAFT AND RECEIVED 0.25" RAIN IN A SHORT TIME, WHILE NEARBY
AREAS SEE LITTLE TO NO RAIN.
SATURDAY WILL FEATURE THE ARRIVAL OF A CHILLY CANADIAN AIR MASS AS
AIRFLOW BECOMES NORTH-NORTHWEST THROUGH A DEEP LAYER OF THE
ATMOSPHERE. 850MB TEMPS WILL DROP TO +6C IN OUR NORTH WITH 9-10C IN
THE SOUTH. ANY DAYTIME HEATING WILL CREATE STEEP LOW LEVEL LAPSE
RATES...WHICH WILL WORK TOGETHER WITH INCREASING BULK SHEAR AND
POSITIVE VORTICITY ADVECTION TO KICK OFF A FEW SHOWERS SATURDAY
AFTERNOON. MOST AREAS WILL PROBABLY REMAIN DRY...AND ANY RAIN THAT
DOES DEVELOP WILL NOT ADD UP TO 0.01"...SO WE WENT WITH SCATTERED
SPRINKLES FOR OUR NORTHERN COUNTIES SAT AFTN.
CLOUD COVER WILL DEVELOP QUICKLY IF ANY SUNSHINE BREAKS THROUGH
FOR ANY LENGTH OF TIME...WHICH WILL HELP TO KEEP HIGHS IN THE
70-73 DEG RANGE. WOULD NOT BE SURPRISED IF SOME LOCATIONS DO NOT
REACH 70 IF THE 6C LINE AT 850MB DOES REACH OUR COUNTIES. DRY
ADIABATIC MIXING OF 6C FROM 850MB WOULD ONLY PRODUCE A HIGH OF
66F. ANY SHOWERS WILL QUICKLY DISSIPATE WITH THE APPROACH OF
SUNSET.
RECORD OR NEAR RECORD LOWS ARE FORECAST FOR SATURDAY NIGHT.
CLEARING SKIES WILL BE A KEY COMPONENT OF THAT HAPPENING...BUT ALL
INDICATIONS ARE THAT CLOUDS WILL BE DIURNALLY DRIVEN AND SHOULD
DISSIPATE SAT EVE. LOW 50S WILL BE COMMON ACROSS THE FORECAST
AREA. RECORD LOW FOR PIA AND SPI SAT NIGHT IS 53.
SUNDAY MAY BE A CARBON COPY OF SATURDAY...WITH THE UPPER TROUGH
LINGERING ACROSS THE WESTERN GREAT LAKES AND INTO EASTERN
ILLINOIS, AND LITTLE CHANGE IN THE AIR MASS. SPOTTY SHOWERS AND
SPRINKLES WILL BE POSSIBLE...MAINLY IN THE NORTH CLOSER TO THE
COLDER AIR.
MONDAY WILL START A WARMING TREND AS THE UPPER TROUGH AXIS DEPARTS
TO THE EAST AND WESTERLY FLOW DEVELOP. THAT WILL SET THE STAGE FOR
A PROGRESSIVE LOW TO MOVE FROM THE PLAINS ACROSS SOUTHERN MISSOURI
AND SOUTHERN IL. SOME LOCALLY HEAVY RAIN WILL BE POSSIBLE LATER
MONDAY NIGHT AS THE LOW APPROACHES AND A WARM FRONT DEVELOPS
NEAR OUR SOUTHERN COUNTIES. THE MODELS HAVE TRENDED FARTHER SOUTH
WITH THE TRACK OF THE LOW THE LAST 2 MODEL RUNS...SO IT IS NOT OUT
OF THE QUESTION THAT LATER RUNS TAKE IT EVEN FARTHER SOUTH. WE
REDUCED LIKELY POPS TO CHANCE MONDAY NIGHT TO TREND DOWN...BUT
ADDED SOME LIKELY TO TUES IN OUR FAR SOUTHERN COUNTIES AS
GFS/ECMWF AGREE ON DECENT COVERAGE OF SHOWERS/STORMS DURING THE
DAY IN SOUTHERN IL RIGHT NOW. PRECIP WILL DIMINISH TUESDAY NIGHT
AS THE BULK OF THE FORCING FOR PRECIP DEPARTS TO THE EAST WITH THE
LOW.
WARMING WILL DEVELOP AHEAD OF THE LOW...AND DEWPOINTS WILL CLIMB
BACK INTO THE 60S WITH THE SYSTEM. LOCALLY HEAVY RAIN MAY DEVELOP
IN THE STRONGER STORMS...WITH RAINFALL RATES OF 1-2 INCHES PER
HOUR.
LONG TERM...WEDNESDAY THROUGH FRIDAY.
WEDNESDAY LOOKS MAINLY DRY AT THIS POINT, ALTHOUGH SOME ISOLATED
SHOWERS/STORMS WILL BE POSSIBLE AS NORTHWEST FLOW RETURNS AND
500MB SHORTWAVES MOVE INTO THE AREA. DEWPOINTS WILL CLIMB INTO THE
UPPER 60S BY WEDNESDAY...SO MUGGY FEELING AIR WILL RETURN AS HIGHS
CLIMB INTO THE LOWER 80S. SOME MID 80S FOR HIGHS WILL BE POSSIBLE
ON THURSDAY AND FRIDAY AS 850MB TEMPS CLIMB BACK TO 14-16C. RAIN
CHANCES INCREASE MORE DRAMATICALLY ON FRIDAY PER THE GFS...WITH A
STRONGER SYSTEM DROPPING SOUTHEAST FROM THE NORTHERN PLAINS. THE
ECMWF LAGS THE GFS BY 24 HRS WITH THAT FEATURE.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
116 PM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT SAT JUL 27 2013
AN ABNORMALLY COOL AND DRY AIRMASS IS CURRENTLY IN PLACE OVER THE
CENTRAL AND NORTHERN PLAINS IN THE FORM OF A SURFACE RIDGE WHICH
EXTENDS FROM SOUTHERN KANSAS NORTHWARD THROUGH NEBRASKA AND INTO THE
NORTHERN PLAINS. THIS AIRMASS IS CHARACTERIZED BY TEMPS IN THE UPPER
40S TO MID 50S ACROSS EASTERN NEBRASKA AND IN THE UPPER 50S TO LOWER
60S THROUGHOUT EASTERN KANSAS. EXPECT THESE TEMPS TO CONTINUE TO
DROP THROUGH THE REST OF THE OVERNIGHT HOURS AND SETTLE AROUND THE
MID TO UPPER 50S FOR OUR FORECAST AREA. RADAR TRENDS SHOW A VERY
WEAK COMPLEX OF SHOWERS AND THUNDERSTORMS IN CENTRAL NEBRASKA. THIS
COMPLEX LOOKS TO BE ASSOCIATED WITH SOME MODERATE ISENTROPIC LIFT
ALONG THE 310K THETA E SURFACE. SOMEWHAT SURPRISING IS THE AMOUNT OF
LIGHTNING DETECTED WITH THESE STORMS AS RAP SOUNDINGS ONLY INDICATE
AROUND 100-200 J/KG OF ELEVATED INSTABILITY FOR THESE STORMS TO WORK
WITH. NONETHELESS HAVE GONE WITH A CHANCE OF ISOLATED THUNDERSTORMS
FOR THE NORTH CENTRAL AND CENTRAL PART OF THE STATE...INCLUDING THE
FAR WESTERN ZONES OF THE FORECAST AREA THROUGH THE MORNING
HOURS...BEFORE GRADUALLY DISSIPATING DURING THE AFTERNOON. WITH THE
COOLER/DRIER AIRMASS IN PLACE OVER THE FORECAST AREA EXPECT TEMPS TO
BE WELL BELOW SEASONAL NORMS...WITH HIGHS REACHING THE MID TO UPPER
70S...WITH PERHAPS A FEW AREAS REACHING 80 DEGREES. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING AS ANOTHER ROUND OF WARM AIR ADVECTION SHOWERS
COMMENCE ACROSS WESTERN AND CENTRAL KANSAS. EXPECT THESE SHOWERS TO
SPILL INTO OUR AREA AND SPREAD EASTWARD OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING. ANOTHER COOL NIGHT IS IN STORE FOR THE AREA ON
SATURDAY NIGHT...AS LOWS WILL LIKELY DROP INTO THE LOWER TO MID 50S
ACROSS THE EASTERN HALF OF THE CWA...WHILE AREAS IN THE WESTERN HALF
WILL STAY IN THE MID TO UPPER 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 324 AM CDT SAT JUL
27 2013
MOISTURE AND PRECIP SLOWLY INCREASE FROM WEST TO EAST ACROSS
EASTERN KANSAS ON SUNDAY...BECOMING LIKELY SUNDAY NIGHT INTO
MONDAY. HIGHS SUNDAY WITH INCREASING CLOUD COVER AND RAIN CHANCES
EXPECTED TO BE IN THE MIDDLE 70S FOR MUCH OF THE AREA. BY 12Z
MONDAY...SURFACE LOW OVER THE TX PANHANDLE GETS A BOOST FROM A
PASSING SHORTWAVE TROF ROLLING OFF THE HIGH PLAINS...INCREASING
MOISTURE ADVECTION AND THE LLJ AND FOCUSING PRECIPITATION ACROSS
EASTERN KANSAS. STILL SOME DISCREPANCIES AS TO HOW FAR NORTH THE
BRUNT OF THE RAIN WILL FALL...WITH NAM ALONG THE I70 CORRIDOR AND
EC FARTHER SOUTHWARD TOWARD SE KS. WILL FAVOR POPS OVER THE
SOUTHERN HALF OF THE AREA AND NOTE THAT PRECIP AMOUNTS COULD BE A
FEW INCHES OR MORE IN SOME LOCATIONS. NO WATCH AT THIS TIME BUT
WILL NEED TO MONITOR EVOLUTION FOR POSSIBLE LOCALIZED FLOODING
CONCERNS ON MONDAY.
SYSTEM MOVES EAST BY MONDAY NIGHT AND EXPECT PRECIP TO END QUICKLY
W TO E EARLY TUESDAY. MAINLY DRY CONDITIONS FORECAST THROUGH
THURSDAY. ZONAL FLOW SLOWLY TRANSITIONS TO WNW FLOW AROUND THE
SOUTHERN UPPER HIGH...AND THIS SLOWLY WARMS TEMPERATURES INTO THE
LOWER 80S TUESDAY TO THE UPPER 80S BY THURSDAY. MAY SEE THE NEXT
CHANCE FOR RAINFALL ON FRIDAY AS ANOTHER SW TROF TRAVERSES THROUGH
THE FLOW BUT HAVE NOT GONE TOO HIGH ON CHANCES THIS FAR OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 106 PM CDT SAT JUL 27 2013
ISOLATED SHOWERS WILL LINGER NEAR THE TAF SITES UNTIL AROUND
20Z...OTHERWISE EXPECT VFR AND DRY CONDITIONS THROUGH THE PERIOD.
CONFIDENCE REMAINS TOO LOW TO INSERT BACK INTO TAFS THIS FCST FOR
KTOP/KFOE...BUT HIGHER POTENTIAL AT KMHK WARRANTS ADDING VCSH BACK
INTO FCST BY 14Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...67
AVIATION...63
AREA FORECAST DISCUSSION
NWS TOPEKA KS
615 AM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT SAT JUL 27 2013
AN ABNORMALLY COOL AND DRY AIRMASS IS CURRENTLY IN PLACE OVER THE
CENTRAL AND NORTHERN PLAINS IN THE FORM OF A SURFACE RIDGE WHICH
EXTENDS FROM SOUTHERN KANSAS NORTHWARD THROUGH NEBRASKA AND INTO THE
NORTHERN PLAINS. THIS AIRMASS IS CHARACTERIZED BY TEMPS IN THE UPPER
40S TO MID 50S ACROSS EASTERN NEBRASKA AND IN THE UPPER 50S TO LOWER
60S THROUGHOUT EASTERN KANSAS. EXPECT THESE TEMPS TO CONTINUE TO
DROP THROUGH THE REST OF THE OVERNIGHT HOURS AND SETTLE AROUND THE
MID TO UPPER 50S FOR OUR FORECAST AREA. RADAR TRENDS SHOW A VERY
WEAK COMPLEX OF SHOWERS AND THUNDERSTORMS IN CENTRAL NEBRASKA. THIS
COMPLEX LOOKS TO BE ASSOCIATED WITH SOME MODERATE ISENTROPIC LIFT
ALONG THE 310K THETA E SURFACE. SOMEWHAT SURPRISING IS THE AMOUNT OF
LIGHTNING DETECTED WITH THESE STORMS AS RAP SOUNDINGS ONLY INDICATE
AROUND 100-200 J/KG OF ELEVATED INSTABILITY FOR THESE STORMS TO WORK
WITH. NONETHELESS HAVE GONE WITH A CHANCE OF ISOLATED THUNDERSTORMS
FOR THE NORTH CENTRAL AND CENTRAL PART OF THE STATE...INCLUDING THE
FAR WESTERN ZONES OF THE FORECAST AREA THROUGH THE MORNING
HOURS...BEFORE GRADUALLY DISSIPATING DURING THE AFTERNOON. WITH THE
COOLER/DRIER AIRMASS IN PLACE OVER THE FORECAST AREA EXPECT TEMPS TO
BE WELL BELOW SEASONAL NORMS...WITH HIGHS REACHING THE MID TO UPPER
70S...WITH PERHAPS A FEW AREAS REACHING 80 DEGREES. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING AS ANOTHER ROUND OF WARM AIR ADVECTION SHOWERS
COMMENCE ACROSS WESTERN AND CENTRAL KANSAS. EXPECT THESE SHOWERS TO
SPILL INTO OUR AREA AND SPREAD EASTWARD OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING. ANOTHER COOL NIGHT IS IN STORE FOR THE AREA ON
SATURDAY NIGHT...AS LOWS WILL LIKELY DROP INTO THE LOWER TO MID 50S
ACROSS THE EASTERN HALF OF THE CWA...WHILE AREAS IN THE WESTERN HALF
WILL STAY IN THE MID TO UPPER 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 324 AM CDT SAT JUL
27 2013
MOISTURE AND PRECIP SLOWLY INCREASE FROM WEST TO EAST ACROSS
EASTERN KANSAS ON SUNDAY...BECOMING LIKELY SUNDAY NIGHT INTO
MONDAY. HIGHS SUNDAY WITH INCREASING CLOUD COVER AND RAIN CHANCES
EXPECTED TO BE IN THE MIDDLE 70S FOR MUCH OF THE AREA. BY 12Z
MONDAY...SURFACE LOW OVER THE TX PANHANDLE GETS A BOOST FROM A
PASSING SHORTWAVE TROF ROLLING OFF THE HIGH PLAINS...INCREASING
MOISTURE ADVECTION AND THE LLJ AND FOCUSING PRECIPITATION ACROSS
EASTERN KANSAS. STILL SOME DISCREPANCIES AS TO HOW FAR NORTH THE
BRUNT OF THE RAIN WILL FALL...WITH NAM ALONG THE I70 CORRIDOR AND
EC FARTHER SOUTHWARD TOWARD SE KS. WILL FAVOR POPS OVER THE
SOUTHERN HALF OF THE AREA AND NOTE THAT PRECIP AMOUNTS COULD BE A
FEW INCHES OR MORE IN SOME LOCATIONS. NO WATCH AT THIS TIME BUT
WILL NEED TO MONITOR EVOLUTION FOR POSSIBLE LOCALIZED FLOODING
CONCERNS ON MONDAY.
SYSTEM MOVES EAST BY MONDAY NIGHT AND EXPECT PRECIP TO END QUICKLY
W TO E EARLY TUESDAY. MAINLY DRY CONDITIONS FORECAST THROUGH
THURSDAY. ZONAL FLOW SLOWLY TRANSITIONS TO WNW FLOW AROUND THE
SOUTHERN UPPER HIGH...AND THIS SLOWLY WARMS TEMPERATURES INTO THE
LOWER 80S TUESDAY TO THE UPPER 80S BY THURSDAY. MAY SEE THE NEXT
CHANCE FOR RAINFALL ON FRIDAY AS ANOTHER SW TROF TRAVERSES THROUGH
THE FLOW BUT HAVE NOT GONE TOO HIGH ON CHANCES THIS FAR OUT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 611 AM CDT SAT JUL 27 2013
A BATCH OF WEAK SHOWERS AND THUNDERSTORMS WILL APPROACH KMHK
WITHIN THE NEXT HOUR AND WILL LIKELY REMAIN NEAR THE TERMINAL
THROUGH 15Z. THE OUTER EXTENT OF THE SHOWERS WILL APPROACH KTOP
AND KMHK BRINGING THE POSSIBILITY OF SOME LIGHT SHOWERS THROUGH 14
TO 15Z. BY NOON THESE SHOWERS SHOULD DISSIPATE LEAVING CLOUDY
SKIES WHICH WILL GRADUALLY CLEAR THROUGH THE REMAINDER OF THE
FORECAST PERIOD.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...67
AVIATION...LEIGHTON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
505 AM CDT SAT JUL 27 2013
...CORRECTED...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT SAT JUL 27 2013
AN ABNORMALLY COOL AND DRY AIRMASS IS CURRENTLY IN PLACE OVER THE
CENTRAL AND NORTHERN PLAINS IN THE FORM OF A SURFACE RIDGE WHICH
EXTENDS FROM SOUTHERN KANSAS NORTHWARD THROUGH NEBRASKA AND INTO THE
NORTHERN PLAINS. THIS AIRMASS IS CHARACTERIZED BY TEMPS IN THE UPPER
40S TO MID 50S ACROSS EASTERN NEBRASKA AND IN THE UPPER 50S TO LOWER
60S THROUGHOUT EASTERN KANSAS. EXPECT THESE TEMPS TO CONTINUE TO
DROP THROUGH THE REST OF THE OVERNIGHT HOURS AND SETTLE AROUND THE
MID TO UPPER 50S FOR OUR FORECAST AREA. RADAR TRENDS SHOW A VERY
WEAK COMPLEX OF SHOWERS AND THUNDERSTORMS IN CENTRAL NEBRASKA. THIS
COMPLEX LOOKS TO BE ASSOCIATED WITH SOME MODERATE ISENTROPIC LIFT
ALONG THE 310K THETA E SURFACE. SOMEWHAT SURPRISING IS THE AMOUNT OF
LIGHTNING DETECTED WITH THESE STORMS AS RAP SOUNDINGS ONLY INDICATE
AROUND 100-200 J/KG OF ELEVATED INSTABILITY FOR THESE STORMS TO WORK
WITH. NONETHELESS HAVE GONE WITH A CHANCE OF ISOLATED THUNDERSTORMS
FOR THE NORTH CENTRAL AND CENTRAL PART OF THE STATE...INCLUDING THE
FAR WESTERN ZONES OF THE FORECAST AREA THROUGH THE MORNING
HOURS...BEFORE GRADUALLY DISSIPATING DURING THE AFTERNOON. WITH THE
COOLER/DRIER AIRMASS IN PLACE OVER THE FORECAST AREA EXPECT TEMPS TO
BE WELL BELOW SEASONAL NORMS...WITH HIGHS REACHING THE MID TO UPPER
70S...WITH PERHAPS A FEW AREAS REACHING 80 DEGREES. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING AS ANOTHER ROUND OF WARM AIR ADVECTION SHOWERS
COMMENCE ACROSS WESTERN AND CENTRAL KANSAS. EXPECT THESE SHOWERS TO
SPILL INTO OUR AREA AND SPREAD EASTWARD OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING. ANOTHER COOL NIGHT IS IN STORE FOR THE AREA ON
SATURDAY NIGHT...AS LOWS WILL LIKELY DROP INTO THE LOWER TO MID 50S
ACROSS THE EASTERN HALF OF THE CWA...WHILE AREAS IN THE WESTERN HALF
WILL STAY IN THE MID TO UPPER 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 324 AM CDT SAT JUL
27 2013
MOISTURE AND PRECIP SLOWLY INCREASE FROM WEST TO EAST ACROSS
EASTERN KANSAS ON SUNDAY...BECOMING LIKELY SUNDAY NIGHT INTO
MONDAY. HIGHS SUNDAY WITH INCREASING CLOUD COVER AND RAIN CHANCES
EXPECTED TO BE IN THE MIDDLE 70S FOR MUCH OF THE AREA. BY 12Z
MONDAY...SURFACE LOW OVER THE TX PANHANDLE GETS A BOOST FROM A
PASSING SHORTWAVE TROF ROLLING OFF THE HIGH PLAINS...INCREASING
MOISTURE ADVECTION AND THE LLJ AND FOCUSING PRECIPITATION ACROSS
EASTERN KANSAS. STILL SOME DISCREPANCIES AS TO HOW FAR NORTH THE
BRUNT OF THE RAIN WILL FALL...WITH NAM ALONG THE I70 CORRIDOR AND
EC FARTHER SOUTHWARD TOWARD SE KS. WILL FAVOR POPS OVER THE
SOUTHERN HALF OF THE AREA AND NOTE THAT PRECIP AMOUNTS COULD BE A
FEW INCHES OR MORE IN SOME LOCATIONS. NO WATCH AT THIS TIME BUT
WILL NEED TO MONITOR EVOLUTION FOR POSSIBLE LOCALIZED FLOODING
CONCERNS ON MONDAY.
SYSTEM MOVES EAST BY MONDAY NIGHT AND EXPECT PRECIP TO END QUICKLY
W TO E EARLY TUESDAY. MAINLY DRY CONDITIONS FORECAST THROUGH
THURSDAY. ZONAL FLOW SLOWLY TRANSITIONS TO WNW FLOW AROUND THE
SOUTHERN UPPER HIGH...AND THIS SLOWLY WARMS TEMPERATURES INTO THE
LOWER 80S TUESDAY TO THE UPPER 80S BY THURSDAY. MAY SEE THE NEXT
CHANCE FOR RAINFALL ON FRIDAY AS ANOTHER SW TROF TRAVERSES THROUGH
THE FLOW BUT HAVE NOT GONE TOO HIGH ON CHANCES THIS FAR OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1111 PM CDT FRI JUL 26 2013
VFR PREVAILS AT KTOP/KFOE/KMHK WITH FOCUS BEING ON OVERNIGHT FOG
POTENTIAL AND POSSIBLE SHOWERS SATURDAY. MID LEVEL CLOUDS OBSERVED
OVER SOUTH CENTRAL NEBRASKA WILL SHIFT SOUTHEAST TOWARDS SITES
OVERNIGHT. THIS FACTOR COMBINED WITH DRIER AIR AT THE LOW LEVELS
AND WINDS THRU 2KFT STAYING MIXY SHOULD KEEP DENSE FOG POTENTIAL
LOW. WIDELY SCATTERED SHOWERS PUSHING SOUTHEAST OVERNIGHT MAY
STILL REACH KMHK AFT 14Z. OTHERWISE NORTH WINDS SHOULD RESIDE
NEAR 10 KTS BEFORE WEAKENING TO AROUND 5 KTS AFT 11Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...67
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
401 AM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT SAT JUL 27 2013
AN ABNORMALLY COOL AND DRY AIRMASS IS CURRENTLY IN PLACE OVER THE
CENTRAL AND NORTHERN PLAINS IN THE FORM OF A SURFACE RIDGE WHICH
EXTENDS FROM SOUTHERN KANSAS NORTHWARD THROUGH NEBRASKA AND INTO THE
NORTHERN PLAINS. THIS AIRMASS IS CHARACTERIZED BY TEMPS IN THE UPPER
40S TO MID 50S ACROSS EASTERN NEBRASKA AND IN THE UPPER 50S TO LOWER
60S THROUGHOUT EASTERN KANSAS. EXPECT THESE TEMPS TO CONTINUE TO
DROP THROUGH THE REST OF THE OVERNIGHT HOURS AND SETTLE AROUND THE
MID TO UPPER 50S FOR OUR FORECAST AREA. RADAR TRENDS SHOW A VERY
WEAK COMPLEX OF SHOWERS AND THUNDERSTORMS IN CENTRAL NEBRASKA. THIS
COMPLEX LOOKS TO BE ASSOCIATED WITH SOME MODERATE ISENTROPIC LIFT
ALONG THE 310K THETA E SURFACE. SOMEWHAT SURPRISING IS THE AMOUNT OF
LIGHTNING DETECTED WITH THESE STORMS AS RAP SOUNDINGS ONLY INDICATE
AROUND 100-200 J/KG OF ELEVATED INSTABILITY FOR THESE STORMS TO WORK
WITH. NONETHELESS HAVE GONE WITH A CHANCE OF ISOLATED THUNDERSTORMS
FOR THE NORTH CENTRAL AND CENTRAL PART OF THE STATE...INCLUDING THE
FAR WESTERN ZONES OF THE FORECAST AREA THROUGH THE MORNING
HOURS...BEFORE GRADUALLY DISSIPATING DURING THE AFTERNOON. WITH THE
COOLER/DRIER AIRMASS IN PLACE OVER THE FORECAST AREA EXPECT TEMPS TO
BE WELL BELOW SEASONAL NORMS...WITH HIGHS REACHING THE MID TO UPPER
70S...WITH PERHAPS A FEW AREAS REACHING 80 DEGREES. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING AS ANOTHER ROUND OF WARM AIR ADVECTION SHOWERS
COMMENCE ACROSS WESTERN AND CENTRAL KANSAS. EXPECT THESE SHOWERS TO
SPILL INTO OUR AREA AND SPREAD EASTWARD OVERNIGHT SATURDAY NIGHT
INTO SUNDAY MORNING. ANOTHER COOL NIGHT IS IN STORE FOR THE AREA ON
SATURDAY NIGHT...AS LOWS WILL LIKELY DROP INTO THE LOWER TO MID 50S
ACROSS THE EASTERN HALF OF THE CWA...WHILE AREAS IN THE WESTERN HALF
WILL STAY IN THE MID TO UPPER 50S.
.LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 324 AM CDT SAT JUL
27 2013
MOISTURE AND PRECIP SLOWLY INCREASE FROM WEST TO EAST ACROSS
EASTERN KANSAS ON SUNDAY...BECOMING LIKELY SUNDAY NIGHT INTO
MONDAY. HIGHS SUNDAY WITH INCREASING CLOUD COVER AND RAIN CHANCES
EXPECTED TO BE IN THE MIDDLE 70S FOR MUCH OF THE AREA. BY 12Z
MONDAY...SURFACE LOW OVER THE TX PANHANDLE GETS A BOOST FROM A
PASSING SHORTWAVE TROF ROLLING OFF THE HIGH PLAINS...INCREASING
MOISTURE ADVECTION AND THE LLJ AND FOCUSING PRECIPITATION ACROSS
EASTERN KANSAS. STILL SOME DISCREPANCIES AS TO HOW FAR NORTH THE
BRUNT OF THE RAIN WILL FALL...WITH NAM ALONG THE I70 CORRIDOR AND
EC FARTHER SOUTHWARD TOWARD SE KS. WILL FAVOR POPS OVER THE
SOUTHERN HALF OF THE AREA AND NOTE THAT PRECIP AMOUNTS COULD BE A
FEW INCHES OR MORE IN SOME LOCATIONS. NO WATCH AT THIS TIME BUT
WILL NEED TO MONITOR EVOLUTION FOR POSSIBLE LOCALIZED FLOODING
CONCERNS ON MONDAY.
SYSTEM MOVES EAST BY MONDAY NIGHT AND EXPECT PRECIP TO END QUICKLY
W TO E EARLY TUESDAY. MAINLY DRY CONDITIONS FORECAST THROUGH
THURSDAY. ZONAL FLOW SLOWLY TRANSITIONS TO WNW FLOW AROUND THE
SOUTHERN UPPER HIGH...AND THIS SLOWLY WARMS TEMPERATURES INTO THE
LOWER 80S TUESDAY TO THE UPPER 80S BY THURSDAY. MAY SEE THE NEXT
CHANCE FOR RAINFALL ON FRIDAY AS ANOTHER SW TROF TRAVERSES THROUGH
THE FLOW BUT HAVE NOT GONE TOO HIGH ON CHANCES THIS FAR OUT.
SURFACE FRONT EXTENDS FROM LOW
OVER THE TX PANHANDLE AND TO THE NE..AND AM SEEING A LITTLE BETTER
AGREEMENT IN BRINGING PRECIP BULLSEYUE INTO NE KS BY THE AFTERNOON
HOURS. SOME SUGGESTION BY THE ECMWF THAT HEAVIEST RAIN WOULD FALL
TO THE SOUTH OF THE AREA...BUT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1111 PM CDT FRI JUL 26 2013
VFR PREVAILS AT KTOP/KFOE/KMHK WITH FOCUS BEING ON OVERNIGHT FOG
POTENTIAL AND POSSIBLE SHOWERS SATURDAY. MID LEVEL CLOUDS OBSERVED
OVER SOUTH CENTRAL NEBRASKA WILL SHIFT SOUTHEAST TOWARDS SITES
OVERNIGHT. THIS FACTOR COMBINED WITH DRIER AIR AT THE LOW LEVELS
AND WINDS THRU 2KFT STAYING MIXY SHOULD KEEP DENSE FOG POTENTIAL
LOW. WIDELY SCATTERED SHOWERS PUSHING SOUTHEAST OVERNIGHT MAY
STILL REACH KMHK AFT 14Z. OTHERWISE NORTH WINDS SHOULD RESIDE
NEAR 10 KTS BEFORE WEAKENING TO AROUND 5 KTS AFT 11Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEIGHTON
LONG TERM...67
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS JACKSON KY
637 PM EDT SAT JUL 27 2013
.UPDATE...
ISSUED AT 637 PM EDT SAT JUL 27 2013
HAVE MODIFIED POP GRIDS FOR TONIGHT INTO SUNDAY MORNING...
INCORPORATING SOME TRENDS FROM THE RUC AND HRRR. THE SHORT TERM RAPID
UPDATE MODELS ARE SHOWING SHOWERS AND POSSIBLY THUNDERSTORMS
DEVELOPING ALONG AND JUST AHEAD OF THE COLD FRONT AS IT MOVES
IN...AND RADAR TRENDS EARLY THIS EVENING SEEM TO LEND SOME SUPPORT
TO THIS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 245 PM EDT SAT JUL 27 2013
SHOWERS AHEAD OF THE COLD FRONT CONTINUE TO CROSS EASTERN KENTUCKY.
FRONT SCHEDULED TO CROSS TONIGHT AND SHOULD BE EAST OF THE STATE BY
SUN MORNING. THEN HIGH PRESSURE BUILDS DOWN FROM CANADA WITH A DRIER
AND COOLER AIR MASS. A FEW SHOWERS THIS EVENING COULD PRODUCE
THUNDER...BUT MOST SHOULD BE JUST LIGHT RAIN. RAINFALL TOTALS WILL
GENERALLY BE LESS THAN A QUARTER OF AN INCH. COOLER AIR WILL BE SLOW
TO INVADE SO OVERNIGHT LOWS WILL DROP TO THE 50S BUT WITH ENOUGH
REMAINING MOISTURE THAT VALLEY FOG MAY STILL BE A PROBLEM. THE COOLER
AIR WILL BATTLE ADDITIONAL SUNSHINE TO HOLD SUNDAY HIGHS TO THE UPPER
70S AND THEN WITH THE INFLUX OF DRIER AIR SUNDAY NIGHT LOWS WILL FALL
INTO THE LOWER 50S. EVEN A FEW UPPER 40S ARE NOT OUT OF THE QUESTION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 249 PM EDT SAT JUL 27 2013
PERIOD WILL START OFF WITH UPPER LEVEL CLOSED LOW LIFTING TO THE NE
AND SURFACE HIGH PRESSURE SITTING OVERHEAD OF THE OHIO VALLEY. WITH
A STRONG JET IN THE UPPER LEVELS PULLING IN DRY AIR FROM THE
NE...ALONG WITH LIGHT NE WINDS AT THE SURFACE...EXPECT TEMPERATURES
TO REMAIN SLIGHTLY BELOW NORMAL AND HUMIDITY LEVELS TO BE LOW.
OVERALL IT WILL BE A BEAUTIFUL DAY WITH HIGH TEMPERATURES STILL
EXPECTED TO ONLY REACH NEAR 80...AND SLIGHTLY LOWER IN THE HIGHER
HILLS ALONG THE KY/VA BORDER. OVERNIGHT TEMPS WILL ONCE AGAIN DROP
DOWN TO BELOW NORMAL...POSSIBLY DROPPING LOWER THAN THE 60 DEGREE
MARK IN MANY LOCATIONS.
BY TUESDAY...HIGH PRESSURE OVER ERNY KY WILL PERSIST IN THE
MORNING/EARLY AFTERNOON WITH SIMILAR TEMPS AND LOW HUMIDITY VALUES.
BY LATE AFTERNOON/EVENING HOWEVER...THINGS WILL BEGIN TO CHANGE.
WHILE THE 500MB LOW CONTINUES TO LIFT NE...MUCH OF THE CONUS WILL
FIND ITSELF IN A MORE ZONAL FLOW. WITHIN THIS ZONAL FLOW A SHORTWAVE
WILL TRAVEL EASTWARD FROM THE COLORADO MOUNTAINS ON SUNDAY TO THE
OHIO VALLEY BY TUESDAY EVENING. THIS WILL TRANSLATE TO A SURFACE
BOUNDARY WHICH WILL PROGRESS WITH THE SYSTEM...AND TRAVERSE EASTERN
KY TUESDAY NIGHT/WEDNESDAY. AS HAS BEEN THE CASE IN PREVIOUS
FORECASTS...MODELS ARE STILL HAVING A HARD TIME COMING INTO
AGREEMENT ON THE EXACT TIMING OF THIS FRONTAL PASSAGE...ALONG WITH
THE TIMING AND COVERAGE OF THE ASSOCIATED CONVECTION. THE LAST TWO
RUNS OF THE GFS HAS SLOWED DOWN THE CONVECTION/S ARRIVAL IN EASTERN
KY UNTIL LATE WEDNESDAY NIGHT/EARLY WEDNESDAY MORNING. THE GEM IS
AGREEING MORE WITH THE GFS...BUT THE 0Z RUN OF THE ECMWF IS BOTH
FASTER IN TIMING AND HIGHER IN COVERAGE AND PRECIP AMOUNTS. SINCE
THIS IS DAY 4...THERE IS STILL PLENTY OF TIME FOR CHANGE AND BETTER
AGREEMENT WITH FUTURE MODEL RUNS...SO WILL CONTINUE WITH A CONSENSUS
AT THIS TIME ON PRECIP TIMING AND COVERAGE. REGARDLESS...NAM AND GFS
MODELS ARE IN GOOD AGREEMENT THAT HIGH LEVEL CLOUDS WILL START
MOVING ACROSS THE AREA AS EARLY AS LATE MONDAY NIGHT/TUESDAY
MORNING...WELL BEFORE ANY PRECIP STARTS. WINDS WILL ALSO TURN MORE
SRLY BY AFTERNOON...PULLING IN WARMER MOISTER AIR FROM THE SOUTH.
NOT ONLY WILL THIS HELP WITH THE PRECIP CHANCES TUESDAY
NIGHT/WEDNESDAY...BUT IT WILL ALSO MEAN THE RETURN OF A MORE HUMID
SUMMER AIR MASS.
AS FAR AS INSTABILITY DURING THE DAY WEDNESDAY...THERE REALLY ISN/T
MUCH. WINDS ARE SHOWING A DECENT VEERING PATTERN...ESPECIALLY IN THE
LOW LEVELS...BUT THE LAPSE RATES AND RESULTING POSITIVE ENERGY ARE
JUST NOT IMPRESSIVE. THE MAIN CONCERN IS THE AMOUNT OF MOISTURE
ASSOCIATED WITH THIS SYSTEM...WITH A SATURATED ATMOSPHERE AND PWAT
VALUES NEARING 1.5 TO 2.0 INCHES EVERY SIX HOURS ACCORDING TO THE
LATEST GFS RUN. WHILE AN EMBEDDED THUNDERSTORM IS NEVER OUT OF THE
QUESTION THIS TIME OF YEAR IN A MOIST AND WARM ENVIRONMENT...THE
MAIN CONCERN ON WEDNESDAY SHOULD JUST BE THE AMOUNT OF RAIN ACROSS
THE REGION AND THE POSSIBILITY FOR FLASH FLOODING AS A RESULT.
THE SURFACE BOUNDARY WILL CONTINUE TO PUSH OFF TO THE SE DURING THE
DAY THURSDAY...WITH PRECIP CHANCES EXPECTED TO CONTINUE THROUGHOUT
THE MORNING AND COME TO AN END DURING THE LATE AFTERNOON/EVENING
HOURS AS DRY AIR ALOFT BEGINS TO WORK IN ACROSS THE REGION AND MAKE
IT/S WAY DOWN TO THE SURFACE. FOR A FEW HOURS LATE THURS MORN/EARLY
AFTERNOON...DRY AIR ALOFT...LLVL MOISTURE...AND STEEPER LAPSE
RATES...WILL TRIGGER A BETTER CHANCE FOR SOME ISL/SCT THUNDERSTORM
DEVELOPMENT /ESPECIALLY IN THE EAST/. THE WINDOW FOR THIS HAPPENING
WILL BE CLOSED PRETTY QUICKLY THOUGH AS DRY AIR MAKES ITS WAY TO THE
SURFACE AND A LLVL INVERSION FORMS BY 0Z FRIDAY. THIS INVERSION AND
DRY AIR /HIGH PRESSURE/ WILL REMAIN IN PLACE THROUGHOUT THE DAY
FRIDAY AND INTO FRIDAY NIGHT. TEMPERATURES WILL BE ON AN INCREASING
TREND TUESDAY THROUGH THE END OF THE WEEK...WITH FRIDAY HAVING THE
HOTTEST TEMPS FORECASTED OF ANY OTHER DAY DURING THE FORECAST
PERIOD. HIGHS WILL TOP OUT IN THE MID 80S ON THIS DAY. BUT WITH A
DRY AIR MASS OVERHEAD AND WINDS ALOFT OUT OF THE NE...EXPECT THE
HUMIDITY LEVELS TO REMAIN AT BAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM EDT SAT JUL 27 2013
A COLD FRONT WILL PUSH ACROSS KENTUCKY TONIGHT...PRODUCING SOME
5-6KFT CIGS TODAY. SOME LIGHT SHOWER ACTIVITY SHOULD INTENSIFY THIS
AFTERNOON WITH A THUNDERSTORM POSSIBLE. GOING TO LEAVE VCTS IN FOR
THE AFTERNOON WITH LOW CONFIDENCE IN ANY THUNDERSTORMS IMPACTING THE
TAF SITES. GFS LAMP GUIDANCE REALLY HAMMERING THE FOG TONIGHT...BUT
WITH DRY AIR ADVECTION BEHIND THE FRONT COMBINED WITH SOME WEAK
NORTHWEST WINDS...OPTED TO GO NO LOWER THAN MVFR VIS BUT COULD SEE
IFR CIGS IN LOW STRATUS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...DUSTY
LONG TERM...JMW
AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS GAYLORD MI
140 AM EDT SAT JUL 27 2013
.SYNOPSIS...
ISSUED AT 415 PM EDT FRI JUL 26 2013
LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL SLOWLY ADVANCE
THROUGH THE STATE...TODAY THROUGH SATURDAY. THIS SYSTEM WILL PRODUCE
A FEW ROUNDS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT...WITH THE
BULK OF THE RAINFALL OCCURRING LATE THIS AFTERNOON AND THIS EVENING.
RAIN MAY BE HEAVY AT TIMES...PARTICULARLY OVER THE EASTERN UPPER
PENINSULA.
BEHIND THE FRONT...SUBSTANTIALLY COOLER AIR WILL SETTLE INTO THE
GREAT LAKES FOR THE UPCOMING WEEKEND KNOCKING TEMPERATURES DOWN TO
WELL BELOW NORMAL READINGS FOR LATE JULY. THIS WILL LEAD TO
ADDITIONAL SHOWERS DEVELOPING ON SATURDAY AND PERSISTING THROUGH
SUNDAY NIGHT.
&&
.UPDATE...
ISSUED AT 132 AM EDT SAT JUL 27 2013
PUT IN SOME UPDATES FOR THE RAIN LEAVING AND THE TEMPERATURES,
FALLING A LITTLE SLOWER THAN FORECASTED EARLIER. THINK THAT THE
CLOUD OVER AND SOME OF THE WINDS ARE HOLDING THE TEMPERATURES A UP
A BIT. OTHERWISE, THE FORECAST IS LOOKING GOOD.
UPDATE ISSUED AT 949 PM EDT FRI JUL 26 2013
CHANGES THIS HOUR: CONTINUE TO REFINE NEAR TERM POPS/WX AS DEEP
MOISTURE PLUME AND ASSOCIATED HEAVIEST RAINFALL EXITS STAGE RIGHT.
IN IT/S WAKE...WE CONTINUE TO BE AHEAD OF THE SURFACE BOUNDARY
THAT IS NOW REACHING GREEN BAY WITH IT/S SIGHTS ON NORTHERN
MICHIGAN OVERNIGHT. BETWEEN THESE TWO FEATURES...HAVE SEEN A FEW
SHOWERS BUBBLE UP...AND EXPECT THAT THIS WILL REMAIN THE CASE
UNTIL FROPA...SO WILL TREND POPS TO SCATTERED THROUGH
MIDNIGHT...BUT LINGER THEM THROUGH MUCH OF THE NIGHT /PARTICULARLY
OVER MY SOUTHEASTERN ZONES.
WILL ADD FOG TO THE GOING FORECAST AFTER MIDNIGHT AS WELL AS
UPSTREAM FOG PRODUCT IMAGERY SUGGESTS THE POTENTIAL FOR AT LEAST A
TEMPORARY THINNING/BREAK IN THE CLOUDINESS...WHICH WITH THIS
EVENING/S RAIN AND CURRENT 0-2F SURFACE DEWPOINT DEPRESSIONS...
WILL LIKELY ALLOW SOME FOG TO GET GOING...BUT LIKELY NOT GET TOO
OUT OF HAND GIVEN LOW STRATUS THAT LOOKS TO ARRIVE SHORTLY BEHIND
THE SURFACE COLD FRONT.
TEMPERATURE TRENDS HAVE BEEN ADJUSTED...BUT INHERITED LOWS RANGING
FROM THE LOWER 50S OVER EASTERN UPPER...TO THE LOWER 60S OVER
NORTHEAST LOWER STILL LOOK RIGHT ON TRACK.
UPDATE ISSUED AT 616 PM EDT FRI JUL 26 2013
CHANGES THIS HOUR: GOING FORECAST DOING JUST FINE AS OF THIS
WRITING...WITH SOME COSMETIC ADJUSTMENTS TO POPS/WEATHER AS RAIN
HAS JUST ABOUT REACHED THE ENTIRE FORECAST AREA. TEMPS HAVE FALLEN
NICELY WITH ARRIVAL OF RAINFALL..SO HAVE TRENDED NEAR TERM
TEMPERATURES DOWN AS WELL.
SEVERE THREAT HAS PRETTY MUCH ENDED WITH MUCAPES DROPPING CWA-WIDE
OVER THE PAST 3 HOURS. LIGHTNING STRIKES ARE FOLLOWING SUIT AS OF
THIS WRITING...BUT SOME EMBEDDED THUNDER CERTAINLY LIKELY THROUGH
THE EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 415 PM EDT FRI JUL 26 2013
SHOWERS AND STORMS ON THE UPSWING THIS AFTERNOON ACROSS THE NORTH
WOODS. WATER VAPOR DEFINITELY HELPS EXPLAIN PART OF THE REASON...WITH
AN UNSEASONABLY STRONG SHORTWAVE TROUGH GOING NEGATIVE TILT BACK
ACROSS THE WESTERN LAKES. NICE MID LEVEL SPEED MAX ALSO NOTED...WITH
CORE OF 50+ KNOT H5 WINDS ROUNDING BASE OF TROUGH INTO SOUTHWEST
WISCONSIN. DEEP LAYER DYNAMICS INTERACTING WITH IN-PLACE RESPECTABLY
MOIST AIRMASS (PWAT VALUES PER RAP GUIDANCE NEAR 1.5 INCHES) HELPING
INDUCE CONVECTIVE DEVELOPMENT. MAIN LINE OF STORMS TIED TO
WISCONSIN/CENTRAL UPPER MICHIGAN COLD FRONT/FRONTAL WAVE WHERE LOW
LEVEL CONVERGENCE/DEEP LAYER DYNAMICS ARE BETTER JUXTAPOSED. MORE
SCATTERED SHOWERS AND STORMS BREAKING OUT ACROSS NORTHERN MICHIGAN
AS SUFFICIENT ML CAPE DEVELOPMENT (UPWARDS OF 500 J/KG) AND OBVIOUS
COOLING OF EARLIER H8-H7 WARM NOSE HAS TIPPED THE SCALE TO MOIST
CONVECTIVE DEVELOPMENT. SO FAR...THINGS HAVE BEEN BEHAVING
THEMSELVES...WITH JUST SOME LOCALLY HEAVY RAIN UNDER THE HEAVIER
CELLS. APPEARS A MUCH NEEDED WIDESPREAD RAIN IS IN THE OFFING THIS
EVENING AS ABOVE DYNAMICS/MOISTURE AXIS SPREAD EAST. FORECAST
CONCERNS CENTER ON SUCH...SPECIFICALLY TIMING OF SHOWERS AND STORMS
AND SEVERE WEATHER POTENTIAL.
UPSCALE GROWTH WILL CONTINUE WITH SHOWERS/STORMS AS DEEP LAYER
DYNAMICS ONLY INCREASE HEADING INTO LATER THIS AFTERNOON AND
EVENING. COLD FRONT EXPECTED TO GET THE BOOT EAST AS MID LEVEL
SUPPORT DOES THE SAME...AND WILL SIMPLY FOLLOW IT AND BEST UPWARD QG
SUPPORT FOR SHOWER/STORM TIMING. EXPECT ALL AREAS TO GET WET...WITH
THE HEAVIEST RAINS EXPECTED ACROSS FAR NORTHWEST LOWER AND EASTERN
UPPER (LOCAL AMOUNTS IN EXCESS OF AN INCH). MAIN LINE OF ACTIVITY
EXPECTED TO SWEEP EAST THIS EVENING...EXITING OFF THE SUNRISE SIDE
DURING THE EARLY MORNING. TEMPORAL DETAIL ACCOUNTS FOR SUCH...USING
CATEGORICAL COVERAGE FOR SPATIAL PURPOSES. NOT OVERLY ENTHUSED ABOUT
SEVERE POTENTIAL...WITH ML CAPE SOMEWHAT ON THE LEAN SIDE...AND
SHOULD CONTINUE TO REMAIN SO. DEEP LAYER EFFECTIVE SHEAR INCREASES
TO OVER 30 KNOTS...WITH 40 KNOT CORE SLIDING ACROSS EASTERN UPPER
LATE THIS AFTERNOON. CANNOT RULE OUT AN ISOLATED SEVERE WIND
GUST/MARGINALLY SEVERE HAILER WITH THE STRONGEST ACTIVITY...BUT A
WIDESPREAD SEVERE EVENT IS NOT EXPECTED. INTERESTINGLY...BACKED LAKE
INDUCED FLOW ACROSS THE TIP THE MITT/NORTHEAST LOWER/EASTERN UPPER
HAS RESULTED IN A TOUCH BETTER STORM ORGANIZATION WITH EVEN SOME
HINTS OF LOW-TOPPED SUPERCELLS. SPOTTER REPORTS NEGATIVE...
HOWEVER...WITH JUST LOCALLY HEAVY RAIN REPORTED WITH THESE CELLS.
WILL DEFINITELY CONTINUE TO MONITOR. POST-FRONTAL LOW LEVEL MOISTURE
SHOULD KEEP RATHER CLOUDY CONDITIONS THROUGH THE EARLY MORNING.
INITIAL SHOT OF CAA NOT OVERLY IMPRESSIVE...WITH LOWS BY SUN-UP
RANGING FROM THE 50S WEST...TO LOWER 60S ALONG NORTHEAST LOWER
COASTLINE.
DRY SLOT CONTINUES INTO SATURDAY MORNING AS MID LEVEL LOW PRESSURE
PINWHEELS INTO NORTHERN WISCONSIN. OFF THE DECK PROFILES REMAIN
RATHER DRY RIGHT THROUGH THE DAY...WITH DEEPER MOISTURE AXIS REMAIN
TO OUR WEST. CAA DROPS H8 TEMPERATURES INTO THE MID SINGLE
DIGITS...MORE THAN COLD ENOUGH TO ENTICE A LAKE RESPONSE (GULP!).
THAT SAID...NOT REALLY ENTHUSED ABOUT LAKE POTENTIAL...WITH DEEP
MOISTURE REMAINING UPSTREAM AND RATHER WEAK/DISORGANIZED LOW LEVEL
WIND FIELDS. MAY SEE SOME POP-UP ACTIVITY DURING THE AFTERNOON WITH
LAND MASS DESTABILIZATION...ESPECIALLY IF THE MORE AGGRESSIVE
NAM-WRF DEPICTIONS ARE REALIZED. HAVE TRENDED FORECAST HEAVILY IN
THIS DIRECTION...FOCUSING "BEST" SHOWER POTENTIAL TO
CLIMATOLOGICALLY FAVORED NORTHEAST LOWER WHERE LOW LEVEL CONVERGENCE
WILL BE MAXIMIZED. THUNDER THREAT NOT INCLUDED...DISCOUNTING THE NAM
AT THIS TIME. LESS SHOWER ACTIVITY LIKELY TO RESULT IN SLIGHTLY WARMER
TEMPERATURES. HAVE NUDGED READINGS UP A FEW DEGREES ACROSS THE
BOARD...BUT NO DOUBT TEMPERATURES WILL BE SEVERAL DEGREES BELOW LATE
JULY NORMALS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 415 PM EDT FRI JUL 26 2013
A RATHER BLOCKED LOOK REMAINS TO THE OVERALL HEMISPHERIC
PATTERN...WITH REX BLOCKING FOUND OVER THE NORTH CENTRAL
PACIFIC...AND A LARGE RIDGE OF HIGH PRESSURE FOUND AROUND IN THE
NORTH ATLANTIC /40W/. IN BETWEEN WE ARE LEFT WITH MEAN TROUGHING
OVER THE GREAT LAKES...WITH A VIGOROUS SHORTWAVE SEEN ON WATER VAPOR
IMAGERY DROPPING INTO THE UPPER MISSISSIPPI VALLEY THAT WILL HAVE
IMPLICATIONS FOR OUR WEEKEND WEATHER. LOOKING AHEAD...THE PATTERN
APPEARS TO BE VERY SLOW TO BREAK DOWN OVER THE NEXT SEVERAL
DAYS...WITH NORTH ATLANTIC HIGH PROGGED TO ACTUALLY RETROGRADE A BIT
BY EARLY NEXT WEEK...BEFORE SLOWLY BREAKING DOWN AND BECOMING
INCREASINGLY PROGRESSIVE LATER NEXT WEEK. THIS IDEA IS REFLECTED IN
THE LATEST NAO ENSEMBLE FORECASTS...MAINTAINING AN OVERALL NEGATIVE
PHASE/BLOCKED/COOLISH PATTERN UNTIL THE BEGINNING OF AUGUST BEFORE
TRENDING MORE NEUTRAL.
SATURDAY NIGHT INTO SUNDAY...MIGHT AS WELL RIP THE JULY AND AUGUST
PAGE RIGHT OFF THE CALENDAR...AS PATTERN FOR THE WEEKEND WILL BE
NOTHING SHORT OF FALL-LIKE. FIRST OFF..APPROACHING SHORT WAVE IS
SCHEDULED TO DROP INTO THE GREAT LAKES AND BECOME CLOSED OFF BY
SUNDAY AS A 555 DM LOW /YIKES!/. THE 500 MB HEIGHT ANOMALY IS AROUND
3 SD BELOW NORMAL FOR THIS TIME OF YEAR PER GEFS STANDARDIZED
ANOMALIES. CORE OF COLDEST AIR LOOKS TO PASS DIRECTLY OVER THE
CWA...WITH H85 TEMPS FALLING AOB 5C DURING THE DAY SUNDAY. BASED
ON PATTERN RECOGNITION AND ABUNDANCE OF H85-H7 MOISTURE PRESENT
DURING THE DAY ON SUNDAY...LOOKING LIKE A PRIME SETUP FOR SOME
INSTABILITY SHOWERS...ESPECIALLY DURING THE AFTERNOON IF WE CAN GET
JUST ENOUGH INSOLATION...DESPITE OVERALL CLOUDY LOOK TO THE
FORECAST. IN ADDITION...ANY SUBTLE VORT MAX ROUNDING MAIN LOW WILL
ALSO CREATE A THREAT FOR SHOWERS. REMOVED THUNDER FROM THE FORECAST
FOR INLAND SPOTS AS I AM NOT CONFIDENT THAT WE WILL HAVE SUFFICIENT
LAPSE RATES AND INSOLATION TO PRODUCE ANY APPRECIABLE CAPE AND
CONVECTIVE DEPTH TO PRODUCE THUNDER. COULD FORESEE SOME GRAUPEL
BEING MIXED GIVEN THE AMOUNT OF COLD AIR ALOFT...BUT TOO SOON TO
INCLUDE SUCH SMALL/MESOSCALE DETAILS IN THE FORECAST ATTM. HIGH
TEMPS ON SUNDAY WILL STRUGGLE TO BREAK THE 60 DEGREE MARK BASED ON
THIS VERY COOL PATTERN...AN KNOCKED OFF A DEGREE OR TWO FROM THE
INHERITED HIGH TEMPERATURES.
OF BIGGER CONCERN IS THE LAKE EFFECT RAIN POTENTIAL /YES...LAKE
EFFECT/...LAKE TEMPS IN THE MID TO UPPER 60S AND AFOREMENTIONED H85
TEMPS WILL CREATE DELTA T`S AROUND 13 TO 18C. THERE IS A DISCREPANCY
BETWEEN THE GUIDANCE OF THE MAIN 1000-850 MB FLOW SUNDAY
NIGHT...WITH THE GFS SUGGESTING MORE OF A SOUTHERLY FLOW FOR NW
LOWER...BUT THE CONSENSUS OFF THE NAM/GEM/ECMWF IS FOR A WEST TO
NORTHWEST ONSHORE WIND DIRECTION...ALBEIT FAIRLY LIGHT. WOULD NOT BE
SURPRISED TO SEE SOME LAKE EFFECT THUNDER WITH LAKE-INDUCED CAPE
VALUES HOVERING AROUND 750 J/KG BASED OFF NAM AND SREF BUFKIT
SOUNDINGS...AND LEFT SLT CHC THUNDER FOR LAKE EFFECT REGIONS THROUGH
SUNDAY. GIVEN THE STRONG INSTABILITY OVER THE LAKES WITH THE UPPER
LOW...ALSO LOOKING LAKE A GOOD SETUP FOR WATERSPOUTS OVER ALL OF THE
GREAT LAKES THROUGH SUNDAY.
SUNDAY NIGHT INTO MONDAY...THE UPPER LOW WILL BE SLOW TO MOVE OFF TO
THE EAST...ALONG WITH THE CORE OF DEEPEST MOISTURE AND BEST FORCING.
DELTA T`S WILL STILL REMAIN FAVORABLE FOR SOME LAKE EFFECT RAIN
SHOWERS FOR NORTHWEST LOWER...ALONG WITH WATERSPOUTS FOR THE GREAT
LAKES THROUGH SUNDAY NIGHT. DRIER MID LEVEL AIR WILL FILTER IN LATE
SUNDAY NIGHT INTO MONDAY...ALONG WITH WEAK SURFACE HIGH PRESSURE
SETTLING INTO THE WESTERN GREAT LAKES. SKIES WILL GRADUALLY CLEAR
FROM WEST TO EAST MONDAY...WITH HIGH TEMPERATURES EXPECTED TO
REBOUND INTO THE MIDDLE 60S TO NEAR 70...ASSUMING SUFFICIENT
SUNSHINE BY AFTERNOON.
MONDAY NIGHT THROUGH FRIDAY...CUTOFF LOW PROGGED TO BE CLEAR OF THE
REGION BY MONDAY NIGHT...WITH HIGH PRESSURE REMAINING IN THE GREAT
LAKES THROUGH TUESDAY NIGHT. SHORT WAVE RIDGING IS EXPECTED TO
SETTLE IN OVERHEAD UNDER A WEST NORTHWEST UPPER LEVEL FLOW REGIME.
THE REGION SHOULD SEE A GOOD DEAL OF SUNSHINE...WITH NEAR TO
SLIGHTLY BELOW NORMAL READINGS FOR TUESDAY ALONG WITH SOME COOL
NIGHTS EXPECTED MONDAY AND TUESDAY NIGHT. THE NEXT SHORTWAVE IN THE
WNW FLOW REGIME DROPS INTO THE GREAT LAKES TUESDAY NIGHT INTO
WEDNESDAY...AND THE ASSOCIATED LOW MOVING THROUGH SOUTHERN ONTARIO
WILL DRAG A COLD FRONT THROUGH THE CWA DURING THIS TIMEFRAME. THIS
WILL PROVIDE THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE
REGION. A SECONDARY STRONGER SHORT WAVE LOOKS TO FOLLOW QUICK ON ITS
HEELS BY FRIDAY. ECMWF/GFS DIFFER ON THE TIMING AND PLACEMENT OF THE
SECOND WAVE...WITH THE NEW 12Z ECMWF SLOWER AND FURTHER NORTH WITH
THE WAVE. WILL HOLD OFF ADDING POPS FOR FRIDAY FOR NOW...AS I DON`T
WANT TO CLUTTER UP THE EXTENDED TOO MUCH WITH AN ALREADY FAIRLY BUSY
WEATHER PATTERN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 132 AM EDT SAT JUL 27 2013
SUMMARY: A COLD FRONT WILL PUSH THROUGH THE TERMINALS OVERNIGHT
TAKING ANY REMAINING SHOWER ACTIVITY AND PUSHING IT EAST. LOW
PRESSURE WILL REMAIN OVER NORTHERN MICHIGAN THROUGH SATURDAY...
HOWEVER...WITH LOW CLOUDS EXPECTED THROUGH THE DAY ALONG WITH A FEW
AFTERNOON SHOWERS.
RESTRICTIONS: CONDITIONS HAVE DETERIORATED TO IFR/MVFR OVER THE PAST
FEW HOURS...AND EXPECT A LITTLE MORE DETERIORATION THROUGH THE
PRE-DAWN HOURS. THIS SHOULD GIVE MBL/TVC/PLN ALL A PERIOD OF IFR
CIGS...WITH LOW MVFR EXPECTED TO HOLD ON AT APN. GRADUAL
IMPROVEMENT IS EXPECTED DURING THE DAY ON SATURDAY WITH VFR
RETURNING TO MBL/TVC/PLN BY AFTERNOON. THERE REMAINS SOME QUESTION
AS TO THE POTENTIAL FOR A SECONDARY LOW PRESSURE SYSTEM TO SPREAD
RAIN BACK TOWARDS APN IN THE AFTERNOON...AND AS SUCH WILL DELAY
IMPROVEMENT TO VFR HERE UNTIL SATURDAY EVENING.
WINDS: WINDS WILL BECOME LIGHT NORTHWEST OVERNIGHT...STRENGTHENING
TO 5-10KTS FOR THE DAY ON SATURDAY BEFORE DIMINISHING TO 5KTS OR
LESS AGAIN SATURDAY EVENING.
&&
.MARINE...
ISSUED AT 415 PM EDT FRI JUL 26 2013
MARINE...GUSTY PRE-FRONTAL SOUTHWEST WINDS TO CONTINUE THROUGH THIS
AFTERNOON...MAINLY IMPACTING NORTHERN LAKE MICHIGAN. PRESSURE
GRADIENT SLACKENS OVERNIGHT...DESPITE COLD FRONTAL PASSAGE. GUSTY
THUNDERSTORM WINDS EXPECTED ALONG THIS FRONT...ESPECIALLY THIS
EVENING. MAINLY LIGHT WEST WINDS EXPECTED THROUGH THIS WEEKEND.
WATERSPOUT POTENTIAL WILL BE ON THE INCREASE THIS WEEKEND AS
UNSEASONABLY STRONG UPPER LEVEL DISTURBANCE SLOWLY ROTATES ACROSS
THE NORTHERN LAKES. PERIODIC SHOWERS ALSO EXPECTED.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JL
SYNOPSIS...KB
SHORT TERM...MB
LONG TERM...NS
AVIATION...ARNOTT
MARINE...MB
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
853 PM MDT Sun Jul 28 2013
.UPDATE...
An update for minor changes to the forecast. After a fairly active
evening with strong to severe thunderstorms over north central
and central Montana, the storms have quieted down. A storm with
heavy rain persists over the hi- line near Cut Bank, otherwise
lighter showers and some thunderstorms exist over central and
southwest Montana. A surge of moisture is expected to drop south
from Alberta overnight. Along with a weak upper level disturbance,
additional precipitation is expected - mainly over the hi-line. The
HRRR and RUC do indicate nocturnal precipitation/thunderstorms. As
a result, have bumped the pops over north central Montana
overnight. Other than this, the wind forecast was tweaked in the
period before midnight. Otherwise, no changes to the forecast. db
&&
.AVIATION...
UPDATED 2350Z.
An unstable airmass and additional low level moisture has resulted
in scattered thunderstorms across the area. Convective activity
should end by 06z. A weak cold front will push south out of Canada
overnight and may bring low clouds and areas of light rain to
portions of North Central Montana. VFR conditions prevail with MVFR
conditions in the vicinity of thunderstorms. MVFR conditions are
possible after 08z associated with light rain showers.
&&
.PREV DISCUSSION...
/ISSUED 550 PM MDT Sun Jul 28 2013/
Tonight through Tuesday...Not much change in the weather can be
expected in the short term period. An upper level low over Central
Alberta/Saskatchewan will remain quasi-stationary through Monday
night before an upper ridge builds over the Pacific Northwest and
Northern Rockies causing the low to accelerate east. Montana will
remain under a generally moist and somewhat unstable southwest to
westerly flow aloft through the short term for scattered showers
and thunderstorms each day. At this time there is nothing to
indicate that storms will become severe but they will become
increasingly moist as precipitable water levels increase across
the region and could bring locally heavy rain and possible
flooding concerns. Temperatures will remain near seasonable levels
each day. mpj
Tuesday Night through Sunday...Medium range forecast models
generally agree on the overall solution through most of the
period, only slightly disagreeing for the upcoming weekend. A weak
upper level ridge of high pressure will remain centered over
western Montana Tuesday night. However, weak disturbances moving
through the ridge will generally keep a slight chance of showers
and thunderstorms over the area. An upper level low pressure area
over the Pacific Northwest coast will then gradually move onshore
and across the Pacific Northwest Wednesday through Friday,
shifting the flow aloft to a more moist and unstable southwesterly
one. Disturbances ejecting from the upper low will move through
the flow and over the area, which the models reflect in higher
precipitation amounts over the area. Have therefore increased the
chances for precipitation during this period, especially so in the
mountains and over the plains of north central/central Montana.
This is due to the fact that the models tend to keep winds
easterly over the plains as surface high pressure remains east of
the area. These easterly winds will advect surface moisture into
the plains areas and move the moisture up the slopes of the Rocky
Mountain Front, making for efficient generation of precipitation.
The unstable flow aloft will also keep at least a slight chance of
thunderstorms around as well through the period, but the increased
chance of wet thunderstorms will help limit new fire starts due to
lightning strikes. Temperatures on Wednesday will warm to a few
degrees below seasonal averages, but the disturbances and
resulting precipitation will help keep high temperatures 5 to 10
degrees below average for this period. The high pressure ridge
will then rebuild into the state from the south for the weekend,
causing the upper low to retrograde back towards the Pacific
Northwest coast. This will decrease the chance of precipitation
and allow temperatures to warm back closer to normal by Sunday.
The only discrepancy is that the ECMWF model is a bit faster than
the GFS/GEM models in rebuilding this ridge, which would mean a
bit quicker of a warm up. Will monitor this situation over the
next few days and make adjustments accordingly. Coulston
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 50 74 51 78 / 40 30 20 20
CTB 48 68 47 72 / 40 20 20 20
HLN 54 79 53 83 / 30 20 10 30
BZN 48 80 48 83 / 30 30 20 20
WEY 36 74 38 74 / 30 20 20 20
DLN 47 81 47 83 / 20 10 10 20
HVR 52 73 51 74 / 40 30 30 30
LWT 51 71 50 75 / 50 50 30 40
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
849 PM MDT Sun Jul 28 2013
.UPDATE...
An update for minor changes to the forecast. After a fairly active
evening with strong to severe thunderstorms over north central and
central Montana, the storms have quieted down. A storm with heavy
rain persists over the hi-line hear Cut Bank, otherwise ligher
showers and some thunderstorms exist over central and southwest
Montana. A surge of moisture is expected to drop south from
Alberta overnight. Along with a weak upper level disturbance,
addition precipitation is expected - mainly over the hi-line. The
HRRR and RUC do indicate nocturnal precipitation/thunderstorms.
As a result, have bumped the pops over north central Montana
overnight. Other than this, the wind forecast was tweaked in the
period before midnight. Otherwise, no changes to the forecast. db
&&
.AVIATION...
UPDATED 2350Z.
An unstable airmass and additional low level moisture has resulted
in scattered thunderstorms across the area. Convective activity
should end by 06z. A weak cold front will push south out of Canada
overnight and may bring low clouds and areas of light rain to
portions of North Central Montana. VFR conditions prevail with MVFR
conditions in the vicinity of thunderstorms. MVFR conditions are
possible after 08z associated with light rain showers.
&&
.PREV DISCUSSION...
/ISSUED 550 PM MDT Sun Jul 28 2013/
Tonight through Tuesday...Not much change in the weather can be
expected in the short term period. An upper level low over Central
Alberta/Saskatchewan will remain quasi-stationary through Monday
night before an upper ridge builds over the Pacific Northwest and
Northern Rockies causing the low to accelerate east. Montana will
remain under a generally moist and somewhat unstable southwest to
westerly flow aloft through the short term for scattered showers
and thunderstorms each day. At this time there is nothing to
indicate that storms will become severe but they will become
increasingly moist as precipitable water levels increase across
the region and could bring locally heavy rain and possible
flooding concerns. Temperatures will remain near seasonable levels
each day. mpj
Tuesday Night through Sunday...Medium range forecast models
generally agree on the overall solution through most of the
period, only slightly disagreeing for the upcoming weekend. A weak
upper level ridge of high pressure will remain centered over
western Montana Tuesday night. However, weak disturbances moving
through the ridge will generally keep a slight chance of showers
and thunderstorms over the area. An upper level low pressure area
over the Pacific Northwest coast will then gradually move onshore
and across the Pacific Northwest Wednesday through Friday,
shifting the flow aloft to a more moist and unstable southwesterly
one. Disturbances ejecting from the upper low will move through
the flow and over the area, which the models reflect in higher
precipitation amounts over the area. Have therefore increased the
chances for precipitation during this period, especially so in the
mountains and over the plains of north central/central Montana.
This is due to the fact that the models tend to keep winds
easterly over the plains as surface high pressure remains east of
the area. These easterly winds will advect surface moisture into
the plains areas and move the moisture up the slopes of the Rocky
Mountain Front, making for efficient generation of precipitation.
The unstable flow aloft will also keep at least a slight chance of
thunderstorms around as well through the period, but the increased
chance of wet thunderstorms will help limit new fire starts due to
lightning strikes. Temperatures on Wednesday will warm to a few
degrees below seasonal averages, but the disturbances and
resulting precipitation will help keep high temperatures 5 to 10
degrees below average for this period. The high pressure ridge
will then rebuild into the state from the south for the weekend,
causing the upper low to retrograde back towards the Pacific
Northwest coast. This will decrease the chance of precipitation
and allow temperatures to warm back closer to normal by Sunday.
The only discrepancy is that the ECMWF model is a bit faster than
the GFS/GEM models in rebuilding this ridge, which would mean a
bit quicker of a warm up. Will monitor this situation over the
next few days and make adjustments accordingly. Coulston
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 50 74 51 78 / 40 30 20 20
CTB 48 68 47 72 / 40 20 20 20
HLN 54 79 53 83 / 30 20 10 30
BZN 48 80 48 83 / 30 30 20 20
WEY 36 74 38 74 / 30 20 20 20
DLN 47 81 47 83 / 20 10 10 20
HVR 52 73 51 74 / 40 30 30 30
LWT 51 71 50 75 / 50 50 30 40
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS BILLINGS MT
251 PM MDT SAT JUL 27 2013
.SHORT TERM...VALID FOR SUN AND MON...
ACTIVE WEATHER IS EXPECTED THE NEXT FEW DAYS AS FLOW ALOFT BECOMES
SOUTHWEST AND SEVERAL WEAK SHORT WAVES CROSS THE REGION.
TONIGHT...WE WILL CONTINUE THE RED FLAG WARNING FOR PARTS OF SOUTH
CENTRAL MT THROUGH 06 UTC. CONVECTION IS SLOWLY DEEPENING OVER THE
REGION AS OF MID AFTERNOON...AND BOTH THE 17 UTC HRRR AND NAM FROM
18 UTC CALL FOR AT LEAST A SCATTERED COVERAGE OF STORMS ACROSS ALL
OF SOUTH CENTRAL MT AS FAR EAST AS BILLINGS THIS EVENING. THE RISK
OF DRY LIGHTNING REMAINS HIGH ENOUGH TO CONTINUE THE RED FLAG EVEN
THOUGH BOUNDARY LAYER HUMIDITIES HAVE STAYED ELEVATED ACROSS PARTS
OF THE GALLATIN NATIONAL FOREST SO FAR TODAY THANKS TO CLOUDS. THE
INVERTED-V SIGNATURES ON FORECAST SOUNDINGS ARE ALSO STILL PRESENT
AND THUS SUGGEST POTENTIALLY GUSTY AND ERRATIC THUNDERSTORM WINDS.
THE CHANCE OF STORMS WILL CONTINUE OVERNIGHT AND GRADUALLY SPREAD
INTO SOUTHEASTERN MT AFTER 06 UTC.
SUN...THE LOWER AND MID 50S F DEWPOINTS OBSERVED ACROSS EASTERN CO
AND SOUTHEASTERN WY SAT AFTERNOON SHOULD GET DRAWN NORTH AND REACH
SOUTHERN MT ON SUN. A SURFACE TROUGH WILL BE CENTERED ACROSS SOUTH
CENTRAL MT WITH AN ATTENDANT WIND SHIFT...AND THAT WILL CONTRIBUTE
TO FOCUSED THUNDERSTORM ACTIVITY SUPPORTIVE OF SOME LIKELY POPS IN
PLACES LIKE SHERIDAN AND MILES CITY. HOWEVER...CONVECTION COULD BE
IN THE CARDS ANYWHERE GIVEN AGITATED SOUTHWEST FLOW AT 500-HPA AND
UPSLOPE LOW-LEVEL FLOW BEHIND THE TROUGH OVER SOUTH CENTRAL MT. IT
LOOKS LIKE A SOLID 500 J/KG OF MLCAPE WILL BE IN PLACE...AND THERE
SHOULD BE POCKETS OF MLCAPE CLOSER TO 1000 J/KG. FORECAST SOUNDING
PROFILES SHOW A RELATIVE WEAKNESS IN WINDS FROM ABOUT 700- TO 500-
HPA...BUT STRONGER FLOW ABOVE THAT STILL YIELDS 30 TO 40 KT OF 0-6
KM BULK SHEAR. GIVEN FAVORABLY STEEP MID-LEVEL LAPSE RATES...THERE
IS POTENTIAL FOR ISOLATED SEVERE STORMS UNTIL NOCTURNAL COOLING IS
ABLE TO REDUCE BOUNDARY LAYER BUOYANCY BY LATE EVENING. WE DECIDED
TO MENTION THAT POSSIBILITY IN THE HAZARDOUS WEATHER OUTLOOK. NOTE
THAT STORMS SUN SHOULD BE WETTER THAN SAT WITH HIGHER PRECIPITABLE
WATER VALUES AND GREATER BOUNDARY LAYER HUMIDITY. IN FACT...WE MAY
HAVE LOCALLY HEAVY RAIN WITH STORMS ALONG THE SURFACE TROUGH WHERE
PRECIPITABLE WATER VALUES MAY EXCEED AN INCH.
MON...THE SURFACE TROUGH WILL MOVE INTO THE DAKOTAS...BUT WE STILL
NEED CHANCE-STYLE POPS ACROSS THE WHOLE AREA IN RESPECT TO UPSLOPE
LOW-LEVEL FLOW ON NORTH-NORTHEAST WINDS BENEATH THE WEST-SOUTHWEST
FLOW ALOFT. A COOLING TREND WILL BE IN PLACE...AND IN FACT WE HAVE
SOME CONCERN THAT THIS SCENARIO COULD BRING COOLER-THAN-ADVERTISED
HIGHS TO THE AREA...ESPECIALLY IF ANY STRATUS AND/OR DEBRIS CLOUDS
FROM CONVECTION HAMPER DIABATIC HEATING AFTER 18 UTC. OUR FORECAST
IS NEAR THE CONSENSUS OF 12 UTC NON-MOS GUIDANCE /WHICH IS USUALLY
A GOOD BET TO PICK UP ON A SITUATION LIKE THIS/ THOUGH...SO WE DID
NOT MAKE ANY CHANGE TO GOING HIGHS FOR NOW. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
EXTENDED PACKAGE LOOKS TO BE IN GOOD SHAPE SO HAVE ONLY MADE A
FEW MINOR ADJUSTMENTS. OVERALL PATTERN LOOKS TO BE UNSETTLED
THROUGH THE UPCOMING WEEK. MODELS ARE MAINLY IN AGREEMENT IN
PLACING A LARGE UPPER LOW OVER THE PACIFIC NORTHWEST THROUGH THE
WEEK RESULTING IN AN UNSETTLED SOUTHWEST FLOW ALOFT ACROSS OUR
FORECAST AREA. SEVERAL DISTURBANCES WILL MOVE OVERHEAD AS WELL BUT
TIMING THIS FAR OUT IS DIFFICULT. AT THIS TIME...THE
WEDNESDAY/THURSDAY TIMEFRAME LOOKS TO HAVE THE HIGHEST CHANCES FOR
MORE WIDESPREAD THUNDERSTORM ACTIVITY. HIGH PRESSURE RIDGING AND
HIGHEST HEIGHTS WILL BE SHUNTED TO THE SOUTH OF OUR STATE. THIS
COMBINED WITH PERIODS OF CLOUDS AND THUNDERSTORM ACTIVITY WILL
RESULT IN DAYTIME TEMPERATURES AT OR SLIGHTLY BELOW NORMAL FOR
THIS TIME OF YEAR. HOOLEY
&&
.AVIATION...
SKIES WILL BE PARTLY TO MOSTLY CLOUDY THIS EVENING THROUGH
TONIGHT. A COLD FRONT WILL MOVE ACROSS THE FORECAST AREA LATE THIS
AFTERNOON FROM KBIL WESTWARD AND ACROSS THE EASTERN AREAS LATE
TONIGHT. EXPECT INCREASING CLOUDS AND A CHANCE FOR THUNDERSTORMS
FROM KBIL WESTWARD LATE THIS AFTERNOON INTO THE EVENING. THE
THUNDERSTORMS WILL HAVE THE POTENTIAL TO PRODUCE STRONG GUSTY
WINDS TO AROUND 50 MPH. EXPECT A SLIGHT THUNDERSTORM CHANCE EAST
OF KBIL LATE THIS EVENING THROUGH THE OVERNIGHT HOURS. MVFR
CONDITIONS WILL BE POSSIBLE IN AND NEAR THUNDERSTORM ACTIVITY.
OTHERWISE...VFR CONDITIONS WILL PREVAIL. THE MOUNTAINS WILL BE
OBSCURED AT TIMES. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 061/081 059/080 058/085 059/086 061/084 060/084 061/084
33/T 53/T 32/T 33/T 32/T 33/T 32/T
LVM 053/084 051/079 049/085 051/085 052/081 051/080 051/080
44/T 53/T 23/T 33/T 33/T 33/T 32/T
HDN 060/085 059/082 058/086 059/086 060/085 060/085 060/085
35/T 64/T 32/T 33/T 32/T 33/T 32/T
MLS 062/085 060/082 060/085 060/086 062/085 062/082 063/085
25/T 74/T 33/T 33/T 34/T 33/T 33/T
4BQ 057/084 056/082 058/083 058/085 058/085 059/083 060/084
24/T 54/T 33/T 33/T 34/T 33/T 33/T
BHK 052/079 056/078 056/079 056/081 058/080 057/080 058/080
23/T 54/T 33/T 32/T 34/T 33/T 34/T
SHR 056/084 055/081 055/086 055/085 056/083 055/083 056/083
35/T 64/T 32/T 33/T 32/T 33/T 33/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...RED FLAG WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONES 28-40-41-63>68.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
347 PM CDT SAT JUL 27 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY AFTERNOON.
ISSUED AT 345 PM CDT SAT JUL 27 2013
FORECAST CONCERNS IN THE SHORT TERM INCLUDE TEMPS WELL BELOW
NORMAL FOR THIS TIME OF YEAR ALONG WITH SMALL PRECIP CHANCES.
CURRENT UPPER AIR...WIND PROFILER NETWORK AND WATER VAPOR SATELLITE
IMAGERY SHOWING AN UPPER LOW OVER THE GREAT LAKES THAT IS EXPECTED
TO WOBBLE IN PLACE THE NEXT 24 HOURS. ANOTHER LOW PRESSURE REGION
WAS OVER EASTERN BRITISH COLUMBIA MOVING INTO ALBERTA...WHILE
FURTHER SOUTH ANOTHER LOW PRESSURE CIRCULATION COULD BE SEEN A
COUPLE HUNDRED MILES OFF THE CENTRAL CALIFORNIA COAST. A WEAK RIDGE
OF HIGH PRESSURE WAS SITUATED OVER THE ROCKIES WITH VARIOUS MINOR
SHORT WAVES ROTATING THROUGH THIS RIDGE...INCLUDING ONE THAT
TRIGGERED ISOLATED TSTMS THIS MORNING. AT THE SURFACE A RIDGE OF
HIGH PRESSURE EXTENDS FROM THE NORTHERN INTO THE CENTRAL PLAINS. LOW
PRESSURE AND AN ASSOCIATED BOUNDARY WAS NOTED OVER THE LEE OF THE
ROCKIES AND THEN EAST ACROSS SOUTHERN OKLAHOMA AND ARKANSAS. CLOSER
TO HOME...WINDS ARE LIGHT DUE TO THE WEAK PRESSURE GRADIENT.
DEWPOINTS WERE VERY COMFORTABLE FOR THIS TIME OF YEAR RANGING FROM
THE MID 40S ACROSS THE NORTHERN CWA TO THE LOWER/MID 50S SOUTH.
FOR TONIGHT...IT APPEARS THE BEST CHANCE FOR RAIN WILL HINGE ON THE
DEGREE OF WARM ADVECTION THAT SETS UP. BOTH THE NAM AND RAP MODELS
ARE IN AGREEMENT IN DEVELOPING A DECENT LOW LEVEL JET AFTER 02Z IN
THE SOUTHERN PART OF THE CWA. THE 310K DEGREE ISENTROPIC PLAN VIEW
PLOT SHOWS THIS NICELY WITH A 30-40 KT JET RIDING OVER THE SURFACE
BOUNDARY AND INTO OUR AREA. MIXING RATIOS HERE ARE AROUND 9-10 G/KG
WITH BEST LIFT IN THE SOUTHWEST. REAL QUESTION THEN BECOME HOW FAR
INTO THE CWA TO EXTEND THE RAIN CHANCES AS WARM ADVECTION NIL OVER
THE NORTHEAST THIRD OF THE CWA ACCORDING TO THE NAM. ANY TSTM
ACTIVITY THAT DOES POP UP OVERNIGHT SHOULD REMAIN BELOW SEVERE
LIMITS AS MU CAPE ONLY A COUPLE HUNDRED J/KG AT BEST EVEN THOUGH
DEEP LAYER SHEAR IS RESPECTABLE. DEWPOINTS TO REMAIN LOW AND GIVEN
THE COOLER AIR MASS...OVERNIGHT LOWS SHOULD BE AROUND 15 DEGREES
BELOW AVERAGE FOR THIS TIME OF YEAR WHICH IS 65 IN KGRI.
PRECIPITATION CHANCES TO CONTINUE DURING THE DAYTIME ON SUNDAY AS
MODELS IN GOOD AGREEMENT IN SLIDING SHORT WAVE TROUGH FROM THE
DESERT SW INTO OUR NECK OF THE WOODS. BEST CHANCES STILL APPEAR TO
BE IN OUR SOUTHERN CWA...ACTUALLY SOUTH OF THERE...CLOSER TO THE
FRONT. ONCE AGAIN...MU CAPE VALUES REMAIN LOW DUE TO THE COOLER LOW
LEVEL TEMPERATURES AND LOWER DEW POINTS...SO SEVERE CHANCES ARE
MINIMAL. HIGHS ON SUNDAY ARE EXPECTED TO REMAIN BELOW NORMAL WITH
COOLER AIR MASS. KGRI AVERAGE HIGH IS 87 AND FORECAST HIGH WILL BE
ABOUT 15 DEGREES BELOW THAT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM CDT SAT JUL 27 2013 MAIN FORECAST CONCERNS WILL
BE CHANCES FOR THUNDERSTORMS AND TEMPERATURES.
GENERALLY NORTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD. THERE ARE
SEVERAL UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
CHANCES FOR PRECIPITATION TO THE AREA. IT CERTAINLY WILL NOT RAIN
ALL THE TIME OR IN ALL LOCATIONS.
THE STRONGEST OF THE UPPER LEVEL WAVES WILL BE MOVING THROUGH THE
AREA SUNDAY NIGHT AND MONDAY. THIS WILL BE THE BEST CHANCE FOR
PRECIPITATION. SUNDAY NIGHT THE UPPER WAVE WILL CONTINUE TO PUSH
THROUGH THE AREA. PRECIPITATION SPREADS A LITTLE TO THE NORTH DURING
THE NIGHT. THIS WILL BE THE BEST CHANCE FOR PRECIPITATION ESPECIALLY
IN THE SOUTH. THE UPPER WAVE WILL START TO MOVE OUT OF THE AREA ON
MONDAY BUT THERE STILL REMAINS A CHANCE FOR SOME SHOWERS AND
THUNDERSTORMS ACROSS THE AREA DURING THE DAY. THE BEST CHANCE WILL
BE IN THE SOUTHEAST PART OF THE AREA.
MONDAY NIGHT BRINGS THE FIRST BREAK...BUT ONLY FOR PART OF THE
FORECAST AREA. A SURFACE HIGH TRIES TO BUILD INTO THE AREA BUT CAN
ONLY BRING A BREAK TO PART OF THE AREA WITH ISOLATED PRECIPITATION
IN THE SOUTHEAST.
FOR THE PERIOD TUESDAY THROUGH WEDNESDAY NIGHT. A SERIES OF WEAK
UPPER LEVEL WAVES WILL MOVE THROUGH THE AREA. THERE ARE CHANCES FOR
THUNDERSTORMS FOR PORTIONS OF THE AREA MAINLY IN THE WEST AND NORTH.
THE CHANCES ARE FAIRLY SMALL AND MODELS HAVE SLIGHTLY DIFFERENT
TIMING OF THE WAVES AS THEY MOVE THROUGH THE AREA.
THURSDAY THROUGH FRIDAY NIGHT THE CHANCES FOR THUNDERSTORMS WILL BE
ACROSS THE ENTIRE AREA. THESE TOO ARE FAIRLY SMALL CHANCES AND IT IS
POSSIBLE THAT THERE MAY NOT BE PRECIPITATION AT SOME LOCATIONS.
A SURFACE HIGH PRESSURE SYSTEM TRIES TO SETTLE INTO THE FORECAST
AREA AGAIN ON SATURDAY AND MOST OF THE AREA WILL BE DRY. THERE IS A
SLIGHT CHANCE IN THE FAR SOUTH.
TEMPERATURES WILL REMAIN ON THE COOL SIDE FOR MONDAY...BUT RETURN TO
MORE SEASONABLE TEMPERATURES FOR THE REST OF THE WEEK WHEN
TEMPERATURES ARE EXPECTED TO BE AT OR A LITTLE BELOW NORMAL FOR THIS
TIME OF YEAR.
&&
.AVIATION...FOR THE 18Z TAF THROUGH 18Z SUNDAY AFTERNOON...ISSUED
AT 1220 PM CDT SAT JUL 27 2013
EXPECT VFR CONDITIONS THROUGH THE FORECAST PERIOD. WITH WEAK HIGH
PRESSURE NOTED OVER THE AREA...EXPECT WINDS TO REMAIN LIGHT THIS
AFTERNOON AND OVERNIGHT BEFORE PICKING UP JUST A LITTLE AND
BECOMING ESE SUNDAY AFTER SUNRISE. SHOWERS HAVE WEAKENED DURING
THE MORNING AND SHOULD BE DRY THE REST OF THE DAY. JUST AN OUTSIDE
CHANCE FOR SOME THUNDERSTORMS OVERNIGHT BUT BETTER CHANCES WELL
SOUTH OF THE TERMINAL AND WILL LEAVE OUT MENTION IN TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...EWALD
LONG TERM...JCB
AVIATION...EWALD
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1242 PM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
TODAY...PER UNR UA SOUNDING AND THE RAP AND NAM MODELS...IT LOOKS
LIKE THERE IS A MOIST AND MODESTLY UNSTABLE EML OPERATING ACROSS THE
FCST AREA. THE NAM...RAP...HRRR AND GEMREG MODELS SEEM TO HAVE A
HANDLE ON THIS DISTURBANCE WITH DIFFERENCES IN THE LOCATION OF THE
RAINFALL. THE CONSENSUS IS FOR THE STORMS ACROSS WRN AND SWRN NEB TO
DECAY OR MOVE OUT OF THE FCST AREA EARLY THIS MORNING WHILE THE
SECOND BAND ACROSS NCNTL NEB CONTINUES TO OPERATE THROUGHOUT THE
MORNING AND THEN DECAYS DURING THE AFTERNOON.
SPC PUBLISHED THIS DISCUSSION AT 742Z...MODERATE MIDLEVEL WAA AND
FRONTOGENESIS IS LOCATED OVER WRN/CNTRL NEB THIS MORNING. IN
ADDITION...A PLUME OF MOISTURE AT 600-700 MB AND STEEP MIDLEVEL
LAPSE RATES IS YIELDING MODERATE MUCAPE VALUES UPWARDS OF 1000 J/KG.
THIS BUOYANCY COMBINED WITH THE ZONE OF FOCUSED MESOSCALE ASCENT IS
RESULTING IN SCATTERED THUNDERSTORM DEVELOPMENT OVER THE AREA. IN
ADDITION...A 60 KT MIDLEVEL NNWLY JET IS CONTRIBUTING TO STRONG
EFFECTIVE BULK SHEAR ON THE ORDER OF 40-60 KT...WHICH IS SUPPORTIVE
OF ELEVATED SUPERCELL DEVELOPMENT. THIS ENVIRONMENT MAY RESULT IN
ISOLATED INSTANCES OF LARGE HAIL DURING THE MORNING...BUT THE THREAT
IS TOO MARGINAL FOR A WW.
TONIGHT...SOME MODEL SOLNS...THE NAM IN PARTICULAR...SUGGEST ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS SWRN
NEB. THE GEMREG IS FARTHER SOUTH HOLDS THE QPF ACROSS KS.
THIS WEATHER SHOULD BE GENERATED BY A DISTURBANCE...CURRENTLY ACROSS
WRN MT...WHICH WILL DROP SOUTH THROUGH THE NW FLOW AND MAINLY AFFECT
THE CNTL HIGH PLAINS BUT THE NAM SHOWS A BURST OF CONVECTION FIRING
ACROSS SWRN NEB. GIVEN THE NORTHWEST FLOW UNDERWAY AND THE APPARENT
FERTILE ENVIRONMENT FOR RAINFALL...THE NAM IS A CREDIBLE SOLN. SO
TSTMS ARE POSSIBLE TONIGHT...MAINLY SOUTH OF INTERSTATE 80.
HIGH TEMPS TODAY SHOULD REMAIN IN THE 70S WITH THE COOL SPOT ACROSS
CUSTER COUNTY...NEAR 70 FOR A HIGH THERE. LOWS TONIGHT IN THE 40S
AND 50S LOOK REASONABLE GIVEN THE COOL HIGH ACROSS SRN MANITOBA AND
BACKED SFC WINDS TUGGING ON THE COOL AIR FROM THE NORTH.
.LONG TERM...
.SUNDAY THROUGH MONDAY...
A FAIRLY COOL PERIOD STARTS THE WEEK AS MODELS ARE IN GOOD AGREEMENT
FOR A SLOW TRANSITION TO A FAIRLY ACTIVE AND WET START OF THE
WEEK. SEVERAL BOUNDARIES WILL COME INTO PLAY AS MOISTURE POOLS
ACROSS THE WEST IN A PREVAILING UPSLOPE PATTERN. A FRONTAL
BOUNDARY WILL EXTEND SOUTH ON THE HIGH PLAINS...WHILE SURFACE
RIDGING REACHES FROM THE NORTHERN MIDWEST THROUGH THE OHIO VALLEY.
AT THIS TIME MONDAY EVENING APPEARS A GOOD SHOT FOR SEVERE
THUNDERSTORM DEVELOPMENT AS THE UPPER RIDGE AXIS WEAKENS AND
EMBEDDED WAVES MOVE EAST IN THE EVENING. IF ALL PANS OUT GOOD
INSTABILITY EXTENDS THROUGH THE FAR NORTHWEST SANDHILLS THAT WOULD
PROVIDE THE ENVIRONMENT FOR SEVERE STORMS MONDAY NIGHT. CONSIDERABLE
CLOUD COVERAGE WILL HELP KEEP TEMPERATURES DOWN AS WELL WITH HIGHS
MAINLY IN 70S... COMPARED TO NORMALS THAT WOULD BE CLOSER TO THE
UPPER 80S.
.TUESDAY THROUGH SATURDAY...
THE PATTERN REMAINS OVERALL PROGRESSIVE WITH SURFACE BOUNDARIES IN
PLACE FOR A CONTINUED CHANCE FOR DAILY THUNDERSTORM ACTIVITY. AS THE
FLOW BECOMES MORE ZONAL TEMPERATURES WILL TREND TOWARD NORMAL BY MIDWEEK.
THE EMBEDDED WAVES CREATE CHALLENGES AS TO THE AREAL COVERAGE OF
STORMS. THE UPPER RIDGE STRENGTHENS ACROSS THE INTERMOUNTAIN
REGION THROUGH MIDWEEK THEN WEAKENS AS THE NEXT UPPER LOW MOVES
INTO THE NORTHEAST PACIFIC. THE RISING HEIGHTS MIDWEEK WILL HELP
SHIFT THE BETTER CHANCE FOR RAIN NORTH UNTIL THE APPROACH OF THE
WEEKEND. TEMPERATURES REBOUND IN THE FAR WEST TUESDAY...ALTHOUGH
IF MODELS SLOW DOWN TEMPERATURES MAY STRUGGLE TO REACH THE 80S.
FOR NOW TRENDED TEMPERATURES UP BEYOND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1242 PM CDT SAT JUL 27 2013
MOSTLY VFR CONDITIONS ARE ANTICIPATED AT KLBF AND KVTN THROUGH 06Z
TONIGHT...HOWEVER ISOLATED LIGHT RAIN SHOWERS CONTINUE EARLY THIS
AFTERNOON ACROSS WESTERN AND SOUTHWEST NEBRASKA...THERE IS A
SLIGHT POSSIBILITY THAT A STRAY SHOWER OR TWO WOULD DRIFT OVER A
TERMINAL AND BRIEFLY REDUCE VISIBILITY TO MVFR. WHILE NOT
ANTICIPATED AT THIS TIME...WILL CONTINUE TO MONITOR. BEYOND 06Z
TONIGHT...ADDITIONAL SHOWERS...POSSIBLY MORE WIDESPREAD...ARE
EXPECTED TO DEVELOP ACROSS SOUTHWEST NEBRASKA AND PORTIONS OF THE
SOUTHERN SANDHILLS. WHILE GUIDANCE IS SOMEWHAT SPLIT WITH TIMING
AND THE LOCATION OF THE QPF...WILL GO AHEAD AND INTRODUCE A PROB30
FOR -SHRA AT KLBF FROM 09-12Z. THERES MUCH LESS CONFIDENCE OF
SEEING STORMS OVERNIGHT AT KVTN...SO WILL NOT INCLUDE ANY MENTION
AT THIS TIME.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...KECK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
634 AM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
TODAY...PER UNR UA SOUNDING AND THE RAP AND NAM MODELS...IT LOOKS
LIKE THERE IS A MOIST AND MODESTLY UNSTABLE EML OPERATING ACROSS THE
FCST AREA. THE NAM...RAP...HRRR AND GEMREG MODELS SEEM TO HAVE A
HANDLE ON THIS DISTURBANCE WITH DIFFERENCES IN THE LOCATION OF THE
RAINFALL. THE CONSENSUS IS FOR THE STORMS ACROSS WRN AND SWRN NEB TO
DECAY OR MOVE OUT OF THE FCST AREA EARLY THIS MORNING WHILE THE
SECOND BAND ACROSS NCNTL NEB CONTINUES TO OPERATE THROUGHOUT THE
MORNING AND THEN DECAYS DURING THE AFTERNOON.
SPC PUBLISHED THIS DISCUSSION AT 742Z...MODERATE MIDLEVEL WAA AND
FRONTOGENESIS IS LOCATED OVER WRN/CNTRL NEB THIS MORNING. IN
ADDITION...A PLUME OF MOISTURE AT 600-700 MB AND STEEP MIDLEVEL
LAPSE RATES IS YIELDING MODERATE MUCAPE VALUES UPWARDS OF 1000 J/KG.
THIS BUOYANCY COMBINED WITH THE ZONE OF FOCUSED MESOSCALE ASCENT IS
RESULTING IN SCATTERED THUNDERSTORM DEVELOPMENT OVER THE AREA. IN
ADDITION...A 60 KT MIDLEVEL NNWLY JET IS CONTRIBUTING TO STRONG
EFFECTIVE BULK SHEAR ON THE ORDER OF 40-60 KT...WHICH IS SUPPORTIVE
OF ELEVATED SUPERCELL DEVELOPMENT. THIS ENVIRONMENT MAY RESULT IN
ISOLATED INSTANCES OF LARGE HAIL DURING THE MORNING...BUT THE THREAT
IS TOO MARGINAL FOR A WW.
TONIGHT...SOME MODEL SOLNS...THE NAM IN PARTICULAR...SUGGEST ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS SWRN
NEB. THE GEMREG IS FARTHER SOUTH HOLDS THE QPF ACROSS KS.
THIS WEATHER SHOULD BE GENERATED BY A DISTURBANCE...CURRENTLY ACROSS
WRN MT...WHICH WILL DROP SOUTH THROUGH THE NW FLOW AND MAINLY AFFECT
THE CNTL HIGH PLAINS BUT THE NAM SHOWS A BURST OF CONVECTION FIRING
ACROSS SWRN NEB. GIVEN THE NORTHWEST FLOW UNDERWAY AND THE APPARENT
FERTILE ENVIRONMENT FOR RAINFALL...THE NAM IS A CREDIBLE SOLN. SO
TSTMS ARE POSSIBLE TONIGHT...MAINLY SOUTH OF INTERSTATE 80.
HIGH TEMPS TODAY SHOULD REMAIN IN THE 70S WITH THE COOL SPOT ACROSS
CUSTER COUNTY...NEAR 70 FOR A HIGH THERE. LOWS TONIGHT IN THE 40S
AND 50S LOOK REASONABLE GIVEN THE COOL HIGH ACROSS SRN MANITOBA AND
BACKED SFC WINDS TUGGING ON THE COOL AIR FROM THE NORTH.
.LONG TERM...
.SUNDAY THROUGH MONDAY...
A FAIRLY COOL PERIOD STARTS THE WEEK AS MODELS ARE IN GOOD AGREEMENT
FOR A SLOW TRANSITION TO A FAIRLY ACTIVE AND WET START OF THE
WEEK. SEVERAL BOUNDARIES WILL COME INTO PLAY AS MOISTURE POOLS
ACROSS THE WEST IN A PREVAILING UPSLOPE PATTERN. A FRONTAL
BOUNDARY WILL EXTEND SOUTH ON THE HIGH PLAINS...WHILE SURFACE
RIDGING REACHES FROM THE NORTHERN MIDWEST THROUGH THE OHIO VALLEY.
AT THIS TIME MONDAY EVENING APPEARS A GOOD SHOT FOR SEVERE
THUNDERSTORM DEVELOPMENT AS THE UPPER RIDGE AXIS WEAKENS AND
EMBEDDED WAVES MOVE EAST IN THE EVENING. IF ALL PANS OUT GOOD
INSTABILITY EXTENDS THROUGH THE FAR NORTHWEST SANDHILLS THAT WOULD
PROVIDE THE ENVIRONMENT FOR SEVERE STORMS MONDAY NIGHT. CONSIDERABLE
CLOUD COVERAGE WILL HELP KEEP TEMPERATURES DOWN AS WELL WITH HIGHS
MAINLY IN 70S... COMPARED TO NORMALS THAT WOULD BE CLOSER TO THE
UPPER 80S.
.TUESDAY THROUGH SATURDAY...
THE PATTERN REMAINS OVERALL PROGRESSIVE WITH SURFACE BOUNDARIES IN
PLACE FOR A CONTINUED CHANCE FOR DAILY THUNDERSTORM ACTIVITY. AS THE
FLOW BECOMES MORE ZONAL TEMPERATURES WILL TREND TOWARD NORMAL BY MIDWEEK.
THE EMBEDDED WAVES CREATE CHALLENGES AS TO THE AREAL COVERAGE OF
STORMS. THE UPPER RIDGE STRENGTHENS ACROSS THE INTERMOUNTAIN
REGION THROUGH MIDWEEK THEN WEAKENS AS THE NEXT UPPER LOW MOVES
INTO THE NORTHEAST PACIFIC. THE RISING HEIGHTS MIDWEEK WILL HELP
SHIFT THE BETTER CHANCE FOR RAIN NORTH UNTIL THE APPROACH OF THE
WEEKEND. TEMPERATURES REBOUND IN THE FAR WEST TUESDAY...ALTHOUGH
IF MODELS SLOW DOWN TEMPERATURES MAY STRUGGLE TO REACH THE 80S.
FOR NOW TRENDED TEMPERATURES UP BEYOND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 633 AM CDT SAT JUL 27 2013
VFR IS EXPECTED MOST AREAS TODAY AND TONIGHT. ISOLATED
THUNDERSTORMS WOULD APPEAR TO BE EXITING THE FCST AREA RATHER
QUICKLY THIS MORNING. SATELLITE INDICATES SOME ENHANCEMENT/INSTABILITY
SUGGESTING PERHAPS REDEVELOPMENT IS POSSIBLE. OTHERWISE THIS
DISTURBANCE SHOULD EXIT SOUTH THIS MORNING.
A NEW DISTURBANCE...CURRENTLY ACROSS SERN MT/NERN WY...IS NOT
HANDLED BY ANY MODEL AND IT WOULD APPEAR ON TRACK TO SPREAD
ISOLATED TO SCATTERED SHOWERS AND TSTMS ACROSS WRN NEB THIS AM.
MEANWHILE...THE MODELS ARE ONBOARD WITH A THIRD DISTURBANCE
PRODUCING SHOWERS AND TSTMS LATE THIS AFTERNOON/EVENING ACROSS ERN WY/ERN
COLO/WRN KS WHICH SHOULD REMAIN SOUTH AND WEST OF THE FCST AREA.
THE NAM SUGGESTS SOME OF THIS ACTIVITY COULD DEVELOP ACROSS SWRN
NEB LATE TONIGHT...FROM 06Z ONWARD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...KECK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
313 AM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
TODAY...PER UNR UA SOUNDING AND THE RAP AND NAM MODELS...IT LOOKS
LIKE THERE IS A MOIST AND MODESTLY UNSTABLE EML OPERATING ACROSS THE
FCST AREA. THE NAM...RAP...HRRR AND GEMREG MODELS SEEM TO HAVE A
HANDLE ON THIS DISTURBANCE WITH DIFFERENCES IN THE LOCATION OF THE
RAINFALL. THE CONSENSUS IS FOR THE STORMS ACROSS WRN AND SWRN NEB TO
DECAY OR MOVE OUT OF THE FCST AREA EARLY THIS MORNING WHILE THE
SECOND BAND ACROSS NCNTL NEB CONTINUES TO OPERATE THROUGHOUT THE
MORNING AND THEN DECAYS DURING THE AFTERNOON.
SPC PUBLISHED THIS DISCUSSION AT 742Z...MODERATE MIDLEVEL WAA AND
FRONTOGENESIS IS LOCATED OVER WRN/CNTRL NEB THIS MORNING. IN
ADDITION...A PLUME OF MOISTURE AT 600-700 MB AND STEEP MIDLEVEL
LAPSE RATES IS YIELDING MODERATE MUCAPE VALUES UPWARDS OF 1000 J/KG.
THIS BUOYANCY COMBINED WITH THE ZONE OF FOCUSED MESOSCALE ASCENT IS
RESULTING IN SCATTERED THUNDERSTORM DEVELOPMENT OVER THE AREA. IN
ADDITION...A 60 KT MIDLEVEL NNWLY JET IS CONTRIBUTING TO STRONG
EFFECTIVE BULK SHEAR ON THE ORDER OF 40-60 KT...WHICH IS SUPPORTIVE
OF ELEVATED SUPERCELL DEVELOPMENT. THIS ENVIRONMENT MAY RESULT IN
ISOLATED INSTANCES OF LARGE HAIL DURING THE MORNING...BUT THE THREAT
IS TOO MARGINAL FOR A WW.
TONIGHT...SOME MODEL SOLNS...THE NAM IN PARTICULAR...SUGGEST ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS SWRN
NEB. THE GEMREG IS FARTHER SOUTH HOLDS THE QPF ACROSS KS.
THIS WEATHER SHOULD BE GENERATED BY A DISTURBANCE...CURRENTLY ACROSS
WRN MT...WHICH WILL DROP SOUTH THROUGH THE NW FLOW AND MAINLY AFFECT
THE CNTL HIGH PLAINS BUT THE NAM SHOWS A BURST OF CONVECTION FIRING
ACROSS SWRN NEB. GIVEN THE NORTHWEST FLOW UNDERWAY AND THE APPARENT
FERTILE ENVIRONMENT FOR RAINFALL...THE NAM IS A CREDIBLE SOLN. SO
TSTMS ARE POSSIBLE TONIGHT...MAINLY SOUTH OF INTERSTATE 80.
HIGH TEMPS TODAY SHOULD REMAIN IN THE 70S WITH THE COOL SPOT ACROSS
CUSTER COUNTY...NEAR 70 FOR A HIGH THERE. LOWS TONIGHT IN THE 40S
AND 50S LOOK REASONABLE GIVEN THE COOL HIGH ACROSS SRN MANITOBA AND
BACKED SFC WINDS TUGGING ON THE COOL AIR FROM THE NORTH.
.LONG TERM...
.SUNDAY THROUGH MONDAY...
A FAIRLY COOL PERIOD STARTS THE WEEK AS MODELS ARE IN GOOD AGREEMENT
FOR A SLOW TRANSITION TO A FAIRLY ACTIVE AND WET START OF THE
WEEK. SEVERAL BOUNDARIES WILL COME INTO PLAY AS MOISTURE POOLS
ACROSS THE WEST IN A PREVAILING UPSLOPE PATTERN. A FRONTAL
BOUNDARY WILL EXTEND SOUTH ON THE HIGH PLAINS...WHILE SURFACE
RIDGING REACHES FROM THE NORTHERN MIDWEST THROUGH THE OHIO VALLEY.
AT THIS TIME MONDAY EVENING APPEARS A GOOD SHOT FOR SEVERE
THUNDERSTORM DEVELOPMENT AS THE UPPER RIDGE AXIS WEAKENS AND
EMBEDDED WAVES MOVE EAST IN THE EVENING. IF ALL PANS OUT GOOD
INSTABILITY EXTENDS THROUGH THE FAR NORTHWEST SANDHILLS THAT WOULD
PROVIDE THE ENVIRONMENT FOR SEVERE STORMS MONDAY NIGHT. CONSIDERABLE
CLOUD COVERAGE WILL HELP KEEP TEMPERATURES DOWN AS WELL WITH HIGHS
MAINLY IN 70S... COMPARED TO NORMALS THAT WOULD BE CLOSER TO THE
UPPER 80S.
.TUESDAY THROUGH SATURDAY...
THE PATTERN REMAINS OVERALL PROGRESSIVE WITH SURFACE BOUNDARIES IN
PLACE FOR A CONTINUED CHANCE FOR DAILY THUNDERSTORM ACTIVITY. AS THE
FLOW BECOMES MORE ZONAL TEMPERATURES WILL TREND TOWARD NORMAL BY MIDWEEK.
THE EMBEDDED WAVES CREATE CHALLENGES AS TO THE AREAL COVERAGE OF
STORMS. THE UPPER RIDGE STRENGTHENS ACROSS THE INTERMOUNTAIN
REGION THROUGH MIDWEEK THEN WEAKENS AS THE NEXT UPPER LOW MOVES
INTO THE NORTHEAST PACIFIC. THE RISING HEIGHTS MIDWEEK WILL HELP
SHIFT THE BETTER CHANCE FOR RAIN NORTH UNTIL THE APPROACH OF THE
WEEKEND. TEMPERATURES REBOUND IN THE FAR WEST TUESDAY...ALTHOUGH
IF MODELS SLOW DOWN TEMPERATURES MAY STRUGGLE TO REACH THE 80S.
FOR NOW TRENDED TEMPERATURES UP BEYOND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1239 AM CDT SAT JUL 27 2013
SHORT RANGE FORECASTS PROJECT THE DEVELOPMENT OF SHOWERS OR
THUNDERSTORMS DEVELOPING 06Z-08Z IN CENTRAL AND NORTH CENTRAL
NEBRASKA TONIGHT. THE SHORT RANGE PROJECTIONS INDICATE THAT THE
SHOWERS/THUNDERSTORMS WILL DEVELOP NORTH AND EAST OF A VTN-MHN-LBF
LINE AND THEY COULD CONTINUE INTO THE MORNING SATURDAY MAYBE TO 16Z.
SINCE VTN IS ON THE NORTHERN EDGE OF THE AREA AND LBF ON THE WESTERN
EDGE...THERE IS LITTLE CONFIDENCE THAT THEY WILL OCCUR AT THE LBF
AND VTN TERMINALS. FOR THE TIME BEING...THEN...WE WILL NOT INCLUDE
THUNDER IN THE TERMINAL FORECASTS FOR VTN AND LBF.
LAST NIGHT...THE EVENING SOUNDING SIGNALED THE POSSIBILITY OF FOG AS
IT HAD A UNIFORM MOISTURE BELOW 1000 FEET AGL WITH A SATURATION
TEMPERATURE OF 59. MIST FOG DID FORM WITH VISIBILITY BELOW 1SM.
TONIGHT...THE EVENING LBF SOUNDING ONCE AGAIN SHOWED UNIFORM
MOISTURE BELOW 1000 FEET AGL BUT THE INDICATED SATURATION
TEMPERATURE IS 47. LOW TEMPERATURES TONIGHT ARE EXPECTED TO REMAIN
WELL ABOVE THAT TEMPERATURE...BR/FG IS NOT LIKELY.
IN THE AREAS NOT AFFECTED BY THE SHOWERS/THUNDERSTORMS...NO
RESTRICTIONS TO FLIGHT OPERATIONS ARE EXPECTED.
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...KECK
AVIATION....CDC
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1036 PM EDT SUN JUL 28 2013
.SYNOPSIS...
SLOW MOVING LOW PRESSURE TRACKING EASTWARD ACROSS THE GREAT LAKES
REGION WILL BRING PERIODS OF SHOWERS TO THE NORTH COUNTRY
TONIGHT. ISOLATED TO SCATTERED SHOWERS REMAIN POSSIBLE MONDAY AND
TUESDAY...BEFORE DRIER WEATHER RETURNS FOR WEDNESDAY...FOLLOWED
BY MORE ACTIVE WEATHER FOR THE REST OF THE WEEK. TEMPERATURES
WILL BE NEAR NORMAL TO SLIGHTLY BELOW.
&&
.NEAR TERM /UNTIL 8 AM MONDAY MORNING/...
AS OF 1036 PM EDT SUNDAY...SCATTERED TO NUMEROUS LIGHT SHOWERS HAVE
OVERSPREAD MOST OF VERMONT /FROM THE NORTHERN CHAMPLAIN VALLEY
EASTWARD/ AT THIS HOUR...WITH AN EMBEDDED BROKEN LINE OF HEAVIER
SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN ADDISON/NORTHERN RUTLAND
COUNTIES. THESE WILL CONTINUE TO MOVE NORTHEASTWARD WITH ANY
THUNDERSTORMS ENDING SHORTLY AFTER MIDNIGHT. FURTHER SOUTH SOME
HEAVIER SHOWERS HAVE DEVELOPED ALONG THE LEADING EDGE OF THE SFC
COLD FRONT AND MID-LEVEL DRY SLOT WHICH MAY DRIFT INTO NORTHERN
NEW YORK. HRRR REFLECTIVITY PROGS...WHICH HAVE GENERALLY PERFORMED
WELL THIS SUMMER...SHOW SHOWER ACTIVITY WINDING DOWN AFTER 09Z.
THEREFORE AM INDICATING A SLOW TAPER DOWN IN POPS BY THAT POINT.
HAVE ALSO SHOWN PATCHY FOG IN EASTERN VT AFTER MIDNIGHT. RAISED
LOW TEMPERATURES UP A FEW DEGREES ACROSS NORTHERN NEW YORK BASED
ON RECENT MOS GUIDANCE. LOWS MID/UPPER 50S FOR SAINT LAWRENCE
VALLEY & DACKS...LOW TO MID 60S FOR THE CHAMPLAIN VALLEY EASTWARD.
&&
.SHORT TERM /8 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 343 PM EDT SUNDAY...DRY SLOT MOVES OVER NRN NY EARLY
MONDAY...BUT LINGERING SHOWERS STILL PSBL...ESP AS MAIN BAND
DOESN/T LOOK TO CLEAR ERN VT TIL MID MORNING. LITTLE BIT OF
INSTABILITY AS THE UPPER LOW CROSSES INTO QUEBEC DURING THE DAY
MONDAY WILL HELP KEEP THREAT OF SHOWERS OVER THE AREA THROUGH THE
EVENING HOURS...ALONG WITH CONTINUED SW FLOW...BEGINNING TO SHIFT
W IN THE LATTER HALF OF THE DAY...AS THE SURFACE FRONT PUSHES
THROUGH AND A MID-LEVEL DRY SLOT MOVES OVER THE REGION. GENERALLY
DRY CONDITIONS CONTINUE INTO MONDAY NIGHT...WITH PWATS OF 1.2 AND
DECREASING WILL FILTER INTO THE REGION ON WESTERLY/NORTHWESTERLY
FLOW. AS THE UPPER FLOW TURNS NORTHWESTERLY TUESDAY SOME
DIURNALLY DRIVEN SHOWERS WILL BE POSSIBLE ACROSS MAINLY NORTHERN
PORTIONS OF THE CWA WITH STEEPENING LAPSE RATES UNDER CAA AND
MODELS SHOW AREA OF EML MOVING OVER NRN SECTIONS OF CWA ON
TUESDAY...HAVE INCLUDED SLGT TO LOW CHC POPS OVER THIS AREA.
TEMPS THROUGHOUT THE PERIOD REMAIN NEAR TO SLIGHTLY BELOW NORMAL
WITH MAX TEMPS IN THE 70S IN THE VALLEYS AND 60S IN THE HIGH
TRRN...AND MIN TEMPS IN THE M40S-M50S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 315 PM EDT SUNDAY...ONCE AGAIN...EXCELLENT CONSISTENCY IN
THE EXTENDED FORECAST DATA WITH DRY WESTERLY FLOW ON WEDNESDAY
ALONG WITH SEASONAL TEMPERATURES. THIS PATTERN IS SHORT LIVED
HOWEVER AS BROAD UPPER TROUGH BEGINS TO GET ESTABLISHED OVER
CENTRAL AND EASTERN CANADA. THE FIRST IN A SERIES OF SHORTWAVE
TROUGHS MOVES THROUGH THE BASE OF THE TROUGH AND INTO OUR AREA
THURSDAY/THURSDAY NIGHT. AS WAS THE CASE YESTERDAY...GOING
FORECAST HAS THIS COVERED WELL...WITH A CHANCE OF SHOWERS DURING
THIS TIME PERIOD. LOOKING AHEAD TO FRIDAY AND SATURDAY...BROAD
UPPER TROUGH REMAINS OVER CENTRAL AND EASTERN CANADA AND CANNOT
RULE OUT THE POSSIBILITY OF SOME SHOWERS...WHICH GOING FORECAST
HAS COVERED. IN ADDITION...LOOKS LIKE TEMPERATURES WILL BE A FEW
DEGREES BELOW NORMAL AT THE BACK END OF THE EXTENDED FORECAST.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
THROUGH 00Z TUESDAY...SHOWERS HAVE LARGELY EXITED NY BUT WILL
STILL ROATE ACROSS VT THRU 04Z. CIGS WILL LARGELY REMAIN IN THE
MVFR CATEGORY FOR THE REMAINDER OF THE PERIOD...BUT VISIBILITIES
WILL BE IN THE VFR CATEGORY. HOWEVER...THERE WILL BE SOME
XCPTNS...MAINLY KSLK WHICH DID SEE SOME RAINFALL AND KMPV WHICH
WILL LIKELY SEE RAINFALL SHORTLY. UPR LOW AND WEAK FLOW ALONG WITH
RECENT SHRA ACTVTY...NOT MUCH BUT HUMID AIRMASS AND CLIMO
SUGGESTING SOME IFR CIGS/VSBY FOR BOTH LOCALES BETWEEN 06-12Z.
WINDS WILL GENERALLY BE LESS THAN 10 KNOTS AND BECOME SOUTHWEST.
A FEW SHOWERS MAY MOVE BACK INTO THE AREA AFTER 14Z...BUT SHOULD
BE ISOLATED TO SCATTERED IN NATURE.
OUTLOOK 00Z TUESDAY THROUGH FRIDAY...UPR LOW CROSSING SRN QUEBEC
MAINTAINS ISOLD -SHRA POTENTIAL ACROSS NRN TAF LOCATIONS MONDAY
INTO TUESDAY. FOG POSSIBLE AT MPV/SLK TUESDAY NIGHT (06-12Z)...
OTHERWISE VFR TUESDAY NIGHT. HIGH PRESSURE IN PLACE WEDNESDAY WITH
MOSTLY CLEAR/VFR CONDITIONS AND LIGHT WINDS ANTICIPATED. NEXT
SHORTWAVE TROUGH BRINGS POTENTIAL FOR SCATTERED RAIN SHOWERS LATE
THURSDAY AFTN.
&&
.EQUIPMENT...
AS OF 749 PM EDT SATURDAY...THE WSR-88D DOPPLER RADAR AT FORT
DRUM NY (KTYX) IS INOPERABLE DUE TO SEVERAL PEDESTAL DYNAMIC
FAULTS EXPERIENCED TODAY. THE OUTAGE IS EXPECTED TO LAST THROUGH
AT LEAST THE REST OF THE WEEKEND INTO PARTS OF MONDAY. UPDATES ON
ITS OPERATIONAL STATUS WILL BE FORTHCOMING ONCE NEW INFORMATION
BECOMES AVAILABLE. WE APOLOGIZE FOR THE OUTAGE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF/KGM
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...EVENSON
AVIATION...EVENSON/SLW
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1101 PM EDT SUN JUL 28 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA LATE TONIGHT BEFORE
STALLING ACROSS THE COASTAL CAROLINAS MONDAY THROUGH THE MID-WEEK
PERIOD. AS A RESULT...A CHANCE FOR CONVECTION WILL EXIST EACH DAY
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. AN UPPER LEVEL
DISTURBANCE WILL APPROACH FROM THE WEST DURING THE MID TO LATE
WEEK PERIOD. THIS WILL ENHANCE THE CONVECTION THREAT THAT ALREADY
EXISTS ACROSS THE FORECAST AREA.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 1045 PM SUNDAY...WILL CONTINUE CHANCE POPS THRUOUT THE
NIGHT...JUST SLOWLY LOWERING THEM TO AN ISOLATED CHANCE BY
DAYBREAK MONDAY. OVERALL...A MUCH MORE QUIETER OVERNIGHT COMPARED
TO LAST NIGHT. THE SFC COLD FRONT IS PROGGED BY THE MODELS TO
REACH JUST WEST OF THE I-95 CORRIDOR JUST WEST OF THE ILM CWA BY
DAYBREAK MONDAY...BEFORE STALLING ALTOGETHER. LATEST HRRR RUNS
INDICATE CONVECTIVE CHANCES TO EXIST THRUOUT THE NIGHT ALONG AND
AHEAD OF THE APPROACHING COLD FRONT. HOWEVER...DECENT SUBSIDENCE
ALOFT TO REACH GA AND SOUTHERN SC DURING THE PRE-DAWN MONDAY HOURS
VIA LATEST NAM 5H VORT PROGS...THUS LIMITING CONVECTION
DEVELOPMENT ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF THE ILM
CWA. AS A RESULT...LOOKING AT MODEST CHANCE OF CONVECTION ALONG
AND WEST OF THE I-95 CORRIDOR LATE THIS EVENING TO ISOLATED ALONG
THE IMMEDIATE COAST. OVERALL...PCPN CHANCES WILL LOWER THE FURTHER
INTO THE NIGHT WE GO. WITH NO APPRECIABLE ADVECTION OF ANY KIND
AT THE SFC OVERNIGHT...MIN TEMPS WILL RANGE IN THE LOW TO MID
70S. A FEW TWEAKS HIGHER ARE NEEDED ALONG THE IMMEDIATE COAST
WHERE ONSHORE WINDS CROSS 80 DEGREE SSTS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...DESPITE THE PRESENCE OF A WEAK SURFACE TROUGH
OVER THE FORECAST AREA THE NEXT FEW DAYS...CONSIDERABLY DRIER AIR
WILL PREVAIL IN THE H6-H3 LAYER MONDAY AND TUESDAY. AS A RESULT
WILL HOLD POP VALUES IN THE SLIGHT CHANCE/ISOLATED CATEGORY. SFC
HEATING AND SEA BREEZE CONVERGENCE IF STRONG ENOUGH COULD HELP SET
OFF CONVECTION...AND PERHAPS MORE-SO ON MONDAY AS THE BASAL
PORTION OF AN UPPER TROUGH SWEEPS EASTWARD ACROSS OUR ZONES AND
SENDS A FEW IMPULSES ACROSS THE FORECAST AREA. STORM EVOLUTION
WILL BE FAVORED IN THE AFTERNOON AND EVENING HOURS. TEMPERATURES
WILL HOLD NEAR CLIMATE STANDARDS FOR LATE JULY BOTH DAYS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SATURDAY...THERE IS VERY LITTLE FLOW IN THE BOUNDARY LAYER
ON WEDNESDAY AS WASHED OUT FRONTAL BOUNDARY LEAVES BEHIND POORLY
DEFINED GRADIENT. MID LEVEL IMPULSES COMING ACROSS LOOK FAIRLY WELL
DEFINED BUT THERE IS POOR AGREEMENT BETWEEN VARIOUS MODELS REGARDING
WHAT LATITUDE THEY CROSS THE COAST AT. EITHER WAY THOUGH THESE
FEATURES SHOULD PROVIDE AMPLE LIFT FOR APPRECIABLE COVERAGE OF
CONVECTION ESPECIALLY CONSIDERING HOW MOIST THE COLUMN IS PROGGED TO
BE. ONCE GUIDANCE SHOWS SOME BETTER AGREEMENT IN THE TRACK OF THE
VORT CENTERS THEN EVEN HIGHER POPS AND FAVORED AREAS MAY BE ABLE TO
BE PICKED OUT. THERE IS STILL SOME SEMBLANCE OF MID LEVEL
TROUGHINESS ON THURSDAY. GFS HAS SHIFTED IT OFFSHORE WHEREAS OLDER
EC AND CONTINUITY HAD IT FURTHER WEST SUPPORTING ANOTHER DAY OF
FAIRLY UNSETTLED WEATHER. EXTRAPOLATING THE WRF OUT IN TIME WOULD
SUGGEST THAT CONTINUITY/WETTER IDEA IS BETTER. FRIDAY AND SATURDAY
WILL BRING MORE ZONAL/WNW FLOW AND A DEVELOPING PIEDMONT TROUGH.
CONVECTION SHOULD TREND DOWN IN COVERAGE...INITIATING ALONG THE
TROUGH AND MOVING EAST INTO WESTERN ZONES. SEA BREEZE TO MAKE
MINIMAL INLAND PROGRESS AND COULD ALSO BRING ISO ACTIVITY. PIEDMONT
TROUGH TO SHARPEN A BIT ON SUNDAY.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...ISOLATED CONVECTION THAT DEVELOPED THIS AFTN/EVENING HAS
BEEN SHORT-LIVED...AND NO STORMS ARE CURRENTLY THREATENING ANY TAF
SITES. AN OUTFLOW BOUNDARY FROM EARLIER OFFSHORE ACTIVITY WILL MOVE
THROUGH KILM/KCRE THIS EVENING WITH WINDS BECOMING S/SE 8-12 KTS FOR
THE NEXT HOUR OR TWO.
FOG/STRATUS ISSUES ARE POSSIBLE OVERNIGHT AS THE SKIES CLEAR
OUT...MAINLY INLAND. HAVE INCLUDED PREVAILING MVFR VSBYS AND SCT
LIFR STRATUS FOR KLBT/KFLO BEGINNING AROUND 08Z...AS WELL AS TEMPO
IFR/LIFR FOR FOG-PRONE KLBT BEFORE 12Z. DO NOT ANTICIPATE ANY VSBY
RESTRICTIONS ALONG THE COAST...THOUGH TEMPO MVFR CIGS CANNOT BE
RULED OUT. WEAK SFC TROUGH OVER THE AREA MONDAY ALONG WITH THE SEA
BREEZE COULD SUPPORT AT LEAST ISOLATED CONVECTION DURING THE DAY.
THEREFORE HAVE INCLUDED VCSH FOR ALL TERMS. STILL EXPECT VFR TO
PREVAIL WITH SW WINDS 6-10 KTS.
EXTENDED OUTLOOK...ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE EXTENDED PERIOD...WITH INCREASED ACTIVITY ON WEDNESDAY
AND THURSDAY. BRIEF LOCALIZED PERIODS OF MVFR/IFR ARE POSSIBLE WITH
THESE STORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM SUNDAY...WINDS AND SEAS OVERNIGHT WILL APPROACH SCEC
CONDITIONS...MAINLY FROM LITTLE RIVER INLET NORTHWARD TO SURF CITY.
INITIAL SFC PRESSURE PATTERN BETWEEN THE WESTERN ATLANTIC HIGH
CENTERED WELL OFFSHORE FROM THE CAROLINAS AND THE SLOW MOVING COLD
FRONT...WILL PRODUCE SSE-SSW WINDS AT 10 TO 20 KT. THE HIER SIDE
OF THIS RANGE ALONG WITH GUSTS UP TO 25 KT WILL OCCUR ACROSS THE
WATERS NORTH OF LITTLE RIVER INLET WHERE THE SFC PG IS JUST
SLIGHTLY TIGHTER. SIGNIFICANT SEAS WILL BECOME DOMINATED BY THE 5
TO 7 SECOND PERIOD WIND DRIVEN WAVES. OVERALL...LOOKING AT 3 TO 4
FOOT HEIGHTS...APPROACHING 5 FT JUST OFFSHORE BEYOND 20 NM OUT
FROM CAPE FEAR. ALL OF THIS EXHIBITED BY THE LATEST OBSERVATIONS
ACROSS THE ILM WATERS...IE OCEAN CREST PIER WITH SSW AT 17G20KT
AND 4 FOOT SEAS...41001 OFF MASONBORO INLET INDICATED 4 FOOT
SEAS...JOHNNY MERCER PIER SSW 15G16KT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...LIGHT TO MODERATE S-SW WIND FLOW IS EXPECTED
ON THE WATERS MONDAY AND TUESDAY...AS A WEAK SURFACE TROUGH HANGS
JUST INLAND OR OVER THE VERY NEAR SHORE WATERS OF THE COAST. SEAS
2-3 FEET ANTICIPATED BOTH DAYS...MAINLY COMPOSED OF SSE WAVES OF
2-3 FEET EVERY 6-7 SECONDS MIXED WITH LIGHT SSW CHOP. ISOLATED
SHOWERS AND THUNDERSTORMS SHOULD BE EXPECTED. THE APPROACH OF AN
UPPER TROUGH MONDAY COULD LEAD TO MORE ACTIVE STORMS FARTHER OUT
OVER THE WEST WALL OF THE GULF STREAM AND AROUND THE FRYING PAN
TOWER AND BUOY AREAS.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 PM SATURDAY...IN THE WAKE OF A WASHED OUT FRONTAL BOUNDARY
WEDNESDAY WILL OFFER UP VERY LIGHT WINDS. THE ILL DEFINED NATURE OF
THE PRESSURE GRADIENT IS CASTING SOME UNCERTAINTY ON THE WIND
DIRECTION FORECAST HOWEVER. NO SWELLS SO SEAS CAPPED AT 3 FT. A
DEVELOPING PIEDMONT TROUGH WILL GIVE THE WINDS A BETTER DEFINED
SOUTHWESTERLY COMPONENT AND SPEED MAY BUMP UP FROM 10KT TO THE
10-15KT RANGE AT TIMES. THIS IS NOT EXPECTED TO BE SIGNIFICANT
ENOUGH TO CAUSE ANY VARIATION IN SEAS THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH
SHORT TERM...MJC
LONG TERM...MBB
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
831 PM EDT SUN JUL 28 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA LATE TONIGHT BEFORE
STALLING ACROSS THE COASTAL CAROLINAS MONDAY THROUGH THE MID-WEEK
PERIOD. AS A RESULT...A CHANCE FOR CONVECTION WILL EXIST EACH DAY
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. AN UPPER LEVEL
DISTURBANCE WILL APPROACH FROM THE WEST DURING THE MID TO LATE
WEEK PERIOD. THIS WILL ENHANCE THE CONVECTION THREAT THAT ALREADY
EXISTS ACROSS THE FORECAST AREA.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 745 PM SUNDAY...WILL CONTINUE CHANCE POPS THRUOUT THE
NIGHT...JUST SLOWLY LOWERING THEM TO AN ISOLATED CHANCE BY
DAYBREAK MONDAY. OVERALL...A MUCH MORE QUIETER NIGHT COMPARED TO
LAST NIGHT. THE SFC COLD FRONT IS PROGGED BY THE MODELS TO REACH
JUST WEST OF THE I-95 CORRIDOR WITHIN THE ILM CWA BY DAYBREAK
MONDAY...BEFORE STALLING ALTOGETHER. LATEST HRRR RUNS INDICATE
CONVECTIVE CHANCES TO EXIST THRUOUT THE NIGHT ALONG AND AHEAD OF
THE APPROACHING COLD FRONT. HOWEVER...DECENT SUBSIDENCE ALOFT TO
REACH GA AND SOUTHERN SC OVERNIGHT VIA LATEST NAM 5H VORT PROGS...
THUS LIMITING CONVECTION DEVELOPMENT. AS A RESULT...LOWER PCPN
CHANCES WILL BE EXHIBITED ACROSS THE SOUTHERN PORTIONS OF THE ILM
CWA COMPARED TO THE ILM NC PORTIONS OF THE CWA. WITH NO
APPRECIABLE ADVECTION OF ANY KIND AT THE SFC OVERNIGHT...MIN TEMPS
WILL RANGE IN THE LOW TO MID 70S...WITH ONLY A FEW TWEAKS NEEDED.
PREVIOUS DISCUSSION...............................................
AS OF 3 PM SUNDAY...THE AREA IS STILL VOID OF ANY SHOWERS
ALTHOUGH THERE ARE SOME ENCOURAGING SIGNS OF A BROKEN LINE
DEVELOPING OFF TO THE NORTHWEST ON A DIFFERENTIAL HEATING
BOUNDARY. SPC MESOANALYSIS PAGE SHOWS THE 500MB VORT AXIS JUST TO
OUR WEST. THE LCL TO LFC MEAN RH IMAGE ON THE SAME SITE SHOWS
ENOUGH MID LEVEL MOISTURE AVAILABLE... AT LEAST ACROSS THE EASTERN
TWO THIRDS OF THE AREA FOR CONVECTION TO DEVELOP.
THE GFS AND NAM STILL WANT TO DEVELOP ACTIVITY MORE TO THE EAST FOR
THE NEXT FEW HOURS. WILL LEAVE CHANCE POPS IN THE FORECAST AND WAIT
FOR A CLEAR SIGNAL TO ADD LIKELY POPS IF IT DEVELOPS. FOR THE
OVERNIGHT HOURS...DRY AIR AT THE MID LEVELS IS LIKELY TO KEEP
ACTIVITY TO A MINIMUM. OVERNIGHT LOWS A DEGREE OR TWO ABOVE GUIDANCE
AGAIN LOOKS LIKE A GOOD PLAY.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...DESPITE THE PRESENCE OF A WEAK SURFACE TROUGH
OVER THE FORECAST AREA THE NEXT FEW DAYS...CONSIDERABLY DRIER AIR
WILL PREVAIL IN THE H6-H3 LAYER MONDAY AND TUESDAY. AS A RESULT
WILL HOLD POP VALUES IN THE SLIGHT CHANCE/ISOLATED CATEGORY. SFC
HEATING AND SEA BREEZE CONVERGENCE IF STRONG ENOUGH COULD HELP SET
OFF CONVECTION...AND PERHAPS MORE-SO ON MONDAY AS THE BASAL
PORTION OF AN UPPER TROUGH SWEEPS EASTWARD ACROSS OUR ZONES AND
SENDS A FEW IMPULSES ACROSS THE FORECAST AREA. STORM EVOLUTION
WILL BE FAVORED IN THE AFTERNOON AND EVENING HOURS. TEMPERATURES
WILL HOLD NEAR CLIMATE STANDARDS FOR LATE JULY BOTH DAYS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SATURDAY...THERE IS VERY LITTLE FLOW IN THE BOUNDARY LAYER
ON WEDNESDAY AS WASHED OUT FRONTAL BOUNDARY LEAVES BEHIND POORLY
DEFINED GRADIENT. MID LEVEL IMPULSES COMING ACROSS LOOK FAIRLY WELL
DEFINED BUT THERE IS POOR AGREEMENT BETWEEN VARIOUS MODELS REGARDING
WHAT LATITUDE THEY CROSS THE COAST AT. EITHER WAY THOUGH THESE
FEATURES SHOULD PROVIDE AMPLE LIFT FOR APPRECIABLE COVERAGE OF
CONVECTION ESPECIALLY CONSIDERING HOW MOIST THE COLUMN IS PROGGED TO
BE. ONCE GUIDANCE SHOWS SOME BETTER AGREEMENT IN THE TRACK OF THE
VORT CENTERS THEN EVEN HIGHER POPS AND FAVORED AREAS MAY BE ABLE TO
BE PICKED OUT. THERE IS STILL SOME SEMBLANCE OF MID LEVEL
TROUGHINESS ON THURSDAY. GFS HAS SHIFTED IT OFFSHORE WHEREAS OLDER
EC AND CONTINUITY HAD IT FURTHER WEST SUPPORTING ANOTHER DAY OF
FAIRLY UNSETTLED WEATHER. EXTRAPOLATING THE WRF OUT IN TIME WOULD
SUGGEST THAT CONTINUITY/WETTER IDEA IS BETTER. FRIDAY AND SATURDAY
WILL BRING MORE ZONAL/WNW FLOW AND A DEVELOPING PIEDMONT TROUGH.
CONVECTION SHOULD TREND DOWN IN COVERAGE...INITIATING ALONG THE
TROUGH AND MOVING EAST INTO WESTERN ZONES. SEA BREEZE TO MAKE
MINIMAL INLAND PROGRESS AND COULD ALSO BRING ISO ACTIVITY. PIEDMONT
TROUGH TO SHARPEN A BIT ON SUNDAY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...ISOLATED CONVECTION THAT DEVELOPED THIS AFTN/EVENING HAS
BEEN SHORT-LIVED...AND NO STORMS ARE CURRENTLY THREATENING ANY TAF
SITES. AN OUTFLOW BOUNDARY FROM EARLIER OFFSHORE ACTIVITY WILL MOVE
THROUGH KILM/KCRE THIS EVENING WITH WINDS BECOMING S/SE 8-12 KTS FOR
THE NEXT HOUR OR TWO.
FOG/STRATUS ISSUES ARE POSSIBLE OVERNIGHT AS THE SKIES CLEAR
OUT...MAINLY INLAND. HAVE INCLUDED PREVAILING MVFR VSBYS AND SCT
LIFR STRATUS FOR KLBT/KFLO BEGINNING AROUND 08Z...AS WELL AS TEMPO
IFR/LIFR FOR FOG-PRONE KLBT BEFORE 12Z. DO NOT ANTICIPATE ANY VSBY
RESTRICTIONS ALONG THE COAST...THOUGH TEMPO MVFR CIGS CANNOT BE
RULED OUT. WEAK SFC TROUGH OVER THE AREA MONDAY ALONG WITH THE SEA
BREEZE COULD SUPPORT AT LEAST ISOLATED CONVECTION DURING THE DAY.
THEREFORE HAVE INCLUDED VCSH FOR ALL TERMS. STILL EXPECT VFR TO
PREVAIL WITH SW WINDS 6-10 KTS.
EXTENDED OUTLOOK...ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE EXTENDED PERIOD...WITH INCREASED ACTIVITY ON WEDNESDAY
AND THURSDAY. BRIEF LOCALIZED PERIODS OF MVFR/IFR ARE POSSIBLE WITH
THESE STORMS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 745 PM SUNDAY...SFC PRESSURE PATTERN BETWEEN THE WESTERN
ATLANTIC HIGH CENTERED WELL OFFSHORE FROM THE CAROLINAS AND THE
SLOW MOVING COLD FRONT...WILL PRODUCE SSE-SSW WINDS AT 10 TO 15
KT. THE HIER SIDE OF THIS RANGE WITH GUSTS UP TO 20 KT WILL OCCUR
ACROSS THE WATERS FROM CAPE FEAR NORTHWARD WHERE THE SFC PG IS
JUST SLIGHTLY TIGHTER. SIGNIFICANT SEAS WILL BECOME DOMINATED BY
THE 5 TO 6 SECOND PERIOD WIND DRIVEN WAVES. OVERALL...LOOKING AT 2
TO 4 FOOT HEIGHTS...APPROACHING 5 FT JUST BEYOND 20 NM OUT FROM
CAPE FEAR NORTHWARD.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...LIGHT TO MODERATE S-SW WIND FLOW IS EXPECTED
ON THE WATERS MONDAY AND TUESDAY...AS A WEAK SURFACE TROUGH HANGS
JUST INLAND OR OVER THE VERY NEAR SHORE WATERS OF THE COAST. SEAS
2-3 FEET ANTICIPATED BOTH DAYS...MAINLY COMPOSED OF SSE WAVES OF
2-3 FEET EVERY 6-7 SECONDS MIXED WITH LIGHT SSW CHOP. ISOLATED
SHOWERS AND THUNDERSTORMS SHOULD BE EXPECTED. THE APPROACH OF AN
UPPER TROUGH MONDAY COULD LEAD TO MORE ACTIVE STORMS FARTHER OUT
OVER THE WEST WALL OF THE GULF STREAM AND AROUND THE FRYING PAN
TOWER AND BUOY AREAS.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 PM SATURDAY...IN THE WAKE OF A WASHED OUT FRONTAL BOUNDARY
WEDNESDAY WILL OFFER UP VERY LIGHT WINDS. THE ILL DEFINED NATURE OF
THE PRESSURE GRADIENT IS CASTING SOME UNCERTAINTY ON THE WIND
DIRECTION FORECAST HOWEVER. NO SWELLS SO SEAS CAPPED AT 3 FT. A
DEVELOPING PIEDMONT TROUGH WILL GIVE THE WINDS A BETTER DEFINED
SOUTHWESTERLY COMPONENT AND SPEED MAY BUMP UP FROM 10KT TO THE
10-15KT RANGE AT TIMES. THIS IS NOT EXPECTED TO BE SIGNIFICANT
ENOUGH TO CAUSE ANY VARIATION IN SEAS THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DCH
NEAR TERM...DCH/SHK
SHORT TERM...MJC
LONG TERM...MBB
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 PM EDT SAT JUL 27 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE CAROLINAS FROM THE WEST
TONIGHT...THEN STALL OUT OVER THE REGION SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM SATURDAY...
CONVERGENT FEATURES ABOUND THIS AFTERNOON. A MOISTURE PLUME AND
SHORT WAVE LIFTING AROUND THE UPPER TROF INITIATED WIDESPREAD RAIN
IN UPSLOPE FLOW ALONG WITH STRONGER CONVECTION IN THE FOOTHILLS
DURING THE MORNING. THESE FEATURES MOVED EAST AND INTO STRONGER
INSTABILITY IN THE PIEDMONT WHERE INSOLATION HAD ALLOWED A
DIFFERENTIAL HEATING BOUNDARY TO SET UP. THE RESULTING AREA OF
SHOWERS AND STORMS WILL CONTINUE TO MOVE EAST AS WE PROGRESS INTO
THE AFTERNOON AND HAVE RAISED POPS ACROSS CENTRAL NC THROUGH THE
EVENING. THE RELATIVELY ORGANIZED LINE OF HEAVIER SHOWERS/STORMS IS
CAPABLE OF PRODUCING RAINFALL RATES OF 2 INCHES PER HOUR...WHICH
COULD PRODUCE MINOR FLOODING IN URBAN AREAS.
RAP AND THE HRRR IN CONJUCTION DEPICT A VORT MAX LIFTING NORTHEAST
OUT OF SOUTH CAROLINA AND ACROSS THE AREA EARLY TONIGHT...PROVIDING
FURTHER SUPPORT FOR CONVECTION ACROSS THE CENTRAL CWFA...
FAY-TRIANGLE AREA...FOR A FEW HOURS AFTER SUNSET. OTHERWISE...
CONVECTION WILL BE WANING TO CHANCE POPS AFTER MIDNIGHT.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 PM SATURDAY...
COLD FRONT WILL BE MOVING ACROSS THE MOUNTAINS EARLY SUNDAY...
MEANWHILE THE UPPER LOW OVER THE GREAT LAKES LIFTS NORTHEAST WITH A
PERSISTENT TROF STRETCHING DOWN THE EAST COAST. IN THE WEST...
MORNING CLOUDINESS WILL INTIALLY HINDER DESTABILIZATION...BUT
MODERATE INSTABILITY WILL DEVELOP WITH THE ARRIVAL OF MID LEVEL
DRIER AIR...PROMOTING A BETTER CHANCE OF DOWNBURST WINDS WITH DCAPE
ON THE ORDER OF 1000J. MEANWHILE...ENTRANCE OF DEPARTING UPPER JET
WILL ALIGN WITH THE BETTER LOW LEVEL CONVERGENCE EAST OF THE SURFACE
FRONT...WHERE PRECIPITABLE WATERS REMAIN >1.75 INCHES WITH MUCAPE
>1200J. AS SUCH...WILL HAVE CHANCE POPS THROUGH THE DAY...SHADED
HIGHER TOWARDS THE EAST. POPS WILL TAPER OFF FROM THE WEST SUNDAY
NIGHT. HIGH TEMPS WILL RANGE FROM THE LOW 80S WEST...WHICH COULD BE
A SHADE WARM IF LOW CLOUDINESS PERSISTS THROUGHOUT THE MORNING...TO
UPPER 80S IN THE EAST. MINS SUNDAY NIGHT WILL BE IN THE 65 TO 70
RANGE.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 245 PM SATURDAY...
THE LONG TERM PERIOD WILL START WITH A COLD FRONT MOVING SLOWLY
ACROSS THE REGION...ALTHOUGH EXACTLY WHERE IT ENDS UP IS STILL IN
QUESTION. IT APPEARS THAT THE FRONT WILL LIKELY STALL/WASH OUT
SOMEWHERE ACROSS EASTERN/SOUTHERN NC. THEREFORE...RESIDUAL
MOISTURE/LIFT ASSOCIATED WITH THE FRONT SHOULD BE ENOUGH TO SUPPORT
SLIGHT CHANCE POPS ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA
ON MONDAY. AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST...ENOUGH
DRYING SHOULD OCCUR FURTHER NORTH AND WEST TO PRECLUDE ANY PRECIP.
THEN MODELS INDICATE THAT THE BEST MOISTURE WILL REMAIN SHUNTED TO
OUR SOUTH AND EAST ON TUESDAY AND THEREFORE AM EXPECTING A MOSTLY
DRY DAY ACROSS THE REGION. THE EXCEPTIONS MAY BE ACROSS THE EXTREME
SOUTH AND EAST (DUE TO THE PROXIMITY OF THE RESIDUAL BOUNDARY AND/OR
MOISTURE) AND THEN BY LATE TUESDAY/TUESDAY NIGHT ACROSS THE WEST AS
MOISTURE BEGINS TO RETURN HERE.
THROUGH THE REMAINDER OF THE EXTENDED PERIOD...THE OVERALL PATTERN
WILL REMAIN FAIRLY PROGRESSIVE AS OUR NEXT UPPER TROUGH/SURFACE COLD
FRONT IS PROGGED TO APPROACH/CROSS THE REGION WEDNESDAY INTO
THURSDAY. THIS WILL RESULT IN INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS...WITH THE BEST CHANCE OF RAIN CURRENTLY LOOKING TO
OCCUR LATE WEDNESDAY INTO THURSDAY. THEN...IT APPEARS THE FRONT WILL
SHIFT EAST OF THE AREA BY FRIDAY MORNING...BUT SIMILAR TO THE PAST
COUPLE OF FRONTS THAT HAVE/WILL IMPACT THE AREA...IT MAY STALL
ACROSS THE EASTERN/SOUTHERN PORTIONS OF THE STATE. THIS WOULD RESULT
IN A SOME PRECIP ACTIVITY...AT LEAST ACROSS THE PORTION OF THE
FORECAST AREA. HOWEVER...IT APPEARS FRIDAY AND SATURDAY SHOULD BE
RELATIVELY DRY AS HIGH PRESSURE BUILDS INTO THE AREA. THEN YET
ANOTHER SYSTEM IS PROGGED TO APPROACH THE AREA LATE IN THE WEEKEND
(MAYBE AS EARLY AS SATURDAY NIGHT).
TEMPS WILL BE DEPENDENT ON THE EXACT TIMING/EXTENT OF ANY PRECIP
THAT OCCURS...BUT SHOULD LARGELY BE NEAR TO SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 200 PM SATURDAY...
24-HR TAF PERIOD:
MVFR CEILINGS AND VISIBILITY WILL BE ASSOCIATED WITH ONGOING
WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORM THIS AFTERNOON OVER
THE WESTERN PIEDMONT. CONDITIONS WILL GRADUALLY SHIFT EAST AS THE
AFTERNOON PROGRESSES...WITH THUNDERSTORMS AT GSO/INT THROUGH
20Z...AND THE VICINITY OF RDU/FAY BY 21Z. STRONGER CONVECTION WILL
DIMINISH WITH LOSS OF HEATING...BUT SCATTERED SHOWERS/ISOLATED
THUNDER WILL PERSIST IN THE EAST THROUGH MIDNIGHT. IFR FOG/STRATUS
ARE EXPECTED AT GSO/INT AFTER MIDNIGHT. MVFR FOG MAY BE EXPECTED IN
THE EASTERN TAF SITES...BUT BOTH CEILING AND VISILITY COULD BE IFR
IF THESE SITES RECEIVE SOME SUBSTANTIAL RAIN THIS EVENING/EARLY
TONIGHT. CONDITIONS WILL IMPROVE TO MVFR/VFR WITH HEATING BETWEEN
12-14Z TOMORROW MORNING.
LOOKING AHEAD:
EXPECT SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS AGAIN SUNDAY
AFTERNOON/EVENING WITH FOG/STRATUS SUNDAY NIGHT...IN ADVANCE OF A
WEAK FRONT APPROACHING THE REGION FROM THE W/NW. DRIER CONDITIONS
SHOULD PREVAIL EARLY NEXT WEEK...THOUGH THE FRONT MAY STILL OVER OR
JUST SOUTH OF CENTRAL NC AND A POTENTIAL FOR MORNING FOG/STRATUS AND
AFTERNOON CONVECTION MAY PERSIST...ESPECIALLY AT KFAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MLM
NEAR TERM...MLM
SHORT TERM...MLM
LONG TERM...KRR
AVIATION...MLM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1047 AM EDT SAT JUL 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND SHIFT OFFSHORE TODAY. A LOW OVER
THE GREAT LAKES WILL MOVE TO THE EAST WITH AN ASSOCIATED COLD
FRONT THAT WILL APPROACH FROM THE WEST SATURDAY NIGHT AND SUNDAY.
HIGH PRESSURE WILL BUILD IN ON MONDAY. INCREASING CHANCES FOR
SHOWERS WILL DEVELOP THE MIDDLE OF NEXT WEEK AHEAD OF THE NEXT
COLD FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM SATURDAY...SHOWERS AND THUNDERSTORMS BEGINNING TO
FILL IN JUST TO OUR WEST OVER THE MIDLANDS OF SOUTH CAROLINA. THE
1200 UTC NAM IS A LITTLE MORE AGGRESSIVE IN DEVELOPING/MOVING
CONVECTION INTO THE AREA LATER THIS AFTERNOON. WE CURRENTLY HAVE
LOW CHANCE POPS FOR THESE AREAS AND WILL LEAVE FOR NOW ALTHOUGH WE
MAY NEED TO ADJUST UPWARD WITH THE NEXT UPDATE. TEMPERATURE AND
CLOUD COVER TRENDS ARE ON TRACK.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...ACTIVE FIRST HALF OF THE PERIOD AS AN UPPER
IMPULSE ROTATING AROUND ANOMALOUSLY DEEP UPPER TROUGH DRIVES A COLD
FRONT ACROSS THE CAROLINAS. THIS OCCURS IN AN ENVIRONMENT WITH
NEARLY 2 INCH PWATS AND MODERATELY STEEP ML LAPSE RATES...SO
CONVECTION SHOULD BE PRETTY WIDESPREAD...AND WILL BUMP TO LOW-LIKELY
SUNDAY AFTN/EVE. DO NOT ANTICIPATE ANY SEVERE...BUT WITH HIGH PWATS
IN PLACE HEAVY RAIN COULD OCCUR WITHIN ANY TSTM. ACTUAL SURFACE
FRONT WILL NOT MOVE OFFSHORE UNTIL LATE MONDAY...BUT MUCH DRIER AIR
BEGINS TO ADVECT INTO THE AREA AHEAD OF THE SURFACE BOUNDARY. SO
WHILE THERE MAY STILL BE ISOLATED CONVECTION...TYPICAL SUMMERTIME
ACTIVITY...ON MONDAY...IT WILL BE MUCH LESS ACTIVE THAN WHAT OCCURS
ON SUNDAY.
MAX TEMPS BOTH DAYS WILL BE A LITTLE BELOW NORMAL FOR THE END OF
JULY...MID/UPR 80S. LOWS AT NIGHT WILL FALL INTO THE 70-73
RANGE...TYPICAL FOR MID-SUMMER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 PM SATURDAY...BROAD UPPER RIDGING AND A RATHER
NON-DESCRIPT SURFACE PRESSURE PATTERN TO BEGIN THE EXTENDED QUICKLY
CHANGES WED-FRI AS UPPER TROUGH RELOADS ACROSS THE EASTERN CONUS.
TUESDAY MAY END UP THE WARMEST DAY OF THE PERIOD AS BROAD UPPER
RIDGING AND SURFACE HIGH PRESSURE MOVE ACROSS THE AREA. ALTHOUGH AN
ISOLATED DIURNAL TSTM CANNOT BE RULE OUT...WILL CARRY ONLY SCHC AS
ANY COVERAGE WILL BE ISOLATED. TEMPS TUESDAY WILL BE RIGHT AROUND
CLIMO FOR HIGHS AND LOWS.
COLD FRONT APPROACHES LATE TUESDAY BUT APPEARS TO GET HUNG UP OVER
THE AREA. THIS SETS UP A RATHER STRANGE SITUATION FOR MID-SUMMER AS
A BROAD LOW PRESSURE MOVES ACROSS THE SOUTHEAST AND OVER THE
CAROLINAS WED/THU ALONG THIS BOUNDARY. EVEN A WEAK BAROCLINIC LOW
THIS TIME OF YEAR IS ABNORMAL...BUT THIS SEASON HAS BEEN QUITE
ATYPICAL THUS FAR...SO WHY NOT! AT THE VERY LEAST...INCREASING
MOISTURE COMBINED WITH A POTENT VORT ALOFT WILL CAUSE BETTER RAIN
CHANCES WED/THU BEFORE DRYING BEGINS ON FRIDAY. COMBINATION OF
REDUCED MID-LEVEL THICKNESSES AND CLOUDS/RAIN WILL KEEP HIGH TEMPS
BELOW CLIMO WED/THU BEFORE RETURNING TO SEASONABLE LEVELS FRIDAY.
MINS THROUGH THE WEEK WILL AVERAGE A DEGREE OR TWO ABOVE NORMAL.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...HIGH CONFIDENCE FOG/STRATUS WILL BURN OFF AS ADVERTISED
IN TAFS. VFR EXPECTED THE REMAINDER OF THE MORNING ALTHOUGH CANNOT
RULE OUT A BRIEF MVFR CIG AS CUMULUS DEVELOPS. LOCAL HRRR SUGGESTS
NO CONVECTION AT THE COAST WITH SHOWERS AND THUNDERSTORMS DEVELOPING
NEAR KFLO 20-21Z AND A HOUR OR TWO LATER AT KLBT. THIS IS CONSISTENT
WITH OTHER MODELS. WILL INDICATE VCTS AT KFLO/KLBT DUE TO UNCERTAINTY
WITH TIMING.
THUNDERSTORMS WILL END DURING THE EVENING BUT LIGHT SHOWERS COULD
CONTINUE THROUGH THE OVERNIGHT HOURS. DESPITE BROKEN CLOUD COVER
THERE IS MODERATE CONFIDENCE MVFR/IFR CONDITIONS WILL DEVELOP
AGAIN AT KFLO/KLBT IN THE PRE-DAWN HOURS WITH TEMPO MVFR AT THE
COASTAL TERMINALS.
EXTENDED OUTLOOK...SCATTERED SHOWERS/THUNDERSTORMS SUNDAY AND
MONDAY AS ANOTHER COLD FRONT APPROACHES THE TERMINALS. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM SATURDAY...NO CHANGES TO THE COASTAL WATERS FORECAST
THIS MORNING AS LIGHT WINDS AND WEAK SEAS PREVAIL.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...LARGE AREA OF HIGH PRESSURE WELL
OFFSHORE...AND A WEAK COLD FRONT SLOWLY MOVING ACROSS THE CAROLINAS
DURING THE SHORT TERM...CREATE A WEAK GRADIENT AND LIGHT WINDS
THROUGH THE EARLY PART OF NEXT WEEK. AHEAD OF THIS FRONT...SW WINDS
WILL BE PREDOMINANT AT AROUND 10 KTS...VEERING TO THE THE WEST AT 10
KTS OR LESS ONLY VERY LATE MONDAY NIGHT. ALTHOUGH THESE WINDS WILL
BE LIGHT...THEY WILL PERSIST FOR A CONSIDERABLE TEMPORAL
PERIOD...THUS DRIVING SEAS TO 2-4 FT EACH DAY. NO SIGNIFICANT SWELL
WILL EXIST WITHIN THE SPECTRUM.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE OFFSHORE AND A
WEAKENING/RESIDUAL BOUNDARY NEAR THE AREA CREATES SOUTHERLY WINDS
WITH LITTLE DIRECTIONAL CHANGE...WITH SPEEDS AROUND 10
KTS...INCREASING TO NEAR 15 KTS LATE WEDNESDAY. SOUTHERLY RETURN
FLOW AROUND OFFSHORE HIGH PRODUCES A 2-3FT/8SEC SE SWELL...WHICH
COMBINES WITH LOW-AMPLITUDE WIND WAVES TO CREATE 2-4 FT SEAS THROUGH
THE PERIOD. LATE TUESDAY AND WEDNESDAY...WEAK BUT MUCH-LONGER PERIOD
SWELL AHEAD OF WEAKENING TROPICAL STORM DORIAN WILL ENTER THE LOCAL
WATERS. ATTM...MAXIMUM SWELL IS FORECAST TO BE 2-3FT/11-12 SEC ON
WEDNESDAY. THIS COULD CREATE SLIGHTLY HIGHER WAVES ACROSS THE WATERS
LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
752 AM EDT SAT JUL 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND SHIFT OFFSHORE TODAY. A LOW OVER
THE GREAT LAKES WILL MOVE TO THE EAST WITH AN ASSOCIATED COLD
FRONT THAT WILL APPROACH FROM THE WEST SATURDAY NIGHT AND SUNDAY.
HIGH PRESSURE WILL BUILD IN ON MONDAY. INCREASING CHANCES FOR
SHOWERS WILL DEVELOP THE MIDDLE OF NEXT WEEK AHEAD OF THE NEXT
COLD FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...LOW STRATUS AND FOG HAVE DEVELOPED ALONG AND
WEST OF THE INTERSTATE 95 CORRIDOR. THE FLORENCE AIRPORT JUST
RECENTLY WENT DOWN TO 1/4 MILE VISIBILITY! WITH ONLY SOME CIRRUS
ALOFT THERE IS NOTHING TO KEEP THE SUN FROM BURNING THIS LOW DECK
OFF QUICKLY THIS MORNING. 06Z MODELS DROPPED THEIR TEMPERATURE
FORECASTS IN LINE WITH MY PREVIOUS THOUGHTS SO NO SIGNIFICANT
CHANGES ARE NECESSARY. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
IT SEEMS AS IF MOST OF THE DISCUSSIONS I HAVE WRITTEN OVER THE PAST
FEW WEEKS HAVE TALKED ABOUT HOW UNUSUAL THE WEATHER PATTERN IS FOR
JULY. TODAY IS NO EXCEPTION: AN ANOMALOUSLY STRONG AND COLD UPPER
LOW OVER LAKE SUPERIOR HAS A TROUGH EXTENDING SOUTHWARD INTO THE MID
SOUTH REGION. 500 MB HEIGHTS AND 850 MB TEMPS BOTH FALL TO -3 TO -4
STANDARD DEVIATIONS FROM NORMAL ACROSS THE UPPER MIDWEST. THE
MID-LEVEL MOISTURE CHANNEL AHEAD OF THIS TROUGH WILL MOVE INTO THE
EASTERN CAROLINAS THIS EVENING AND SHOULD REMAIN OVERNIGHT. AT THE
SURFACE A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH LIES FROM
INDIANA TO MISSOURI. AN OLD STALLED FRONT IS DECAYING WELL EAST OF
THE CAROLINA COAST...BUT SATELLITE IMAGERY AND DATA FROM NOAA BUOY
41002 INDICATE A SMALL LOW HAS WRAPPED UP ABOUT 200 MILES EAST OF
CAPE FEAR. THIS LOW IS FORECAST TO MOVE NORTHEAST AND AWAY FROM THE
AREA WITH VIRTUALLY NO IMPACT LOCALLY.
SATELLITE IMAGERY ALSO SHOWS FAIRLY THICK CIRRUS OVER THE WESTERN
HALF OF THE CAROLINAS ASSOCIATED WITH PERSISTENT THUNDERSTORM
ACTIVITY OVERNIGHT. THERE MAY BE MORE OPAQUE CLOUD COVER HERE THAN
ACCOUNTED FOR IN 00Z MODELS...AND THAT LEADS INTO THE UNCERTAINTY
WITH TODAY`S FORECAST. ASSUMING WE HAVE MORE CLOUDS THAN SUN THIS
MORNING BUT WE GET A FAIR AMOUNT OF SUNSHINE FROM NOON ONWARD...
HIGHS SHOULD REACH THE UPPER 80S INLAND AND MID 80S AT THE COAST. IF
THICKER CIRRUS (OR EVEN MID-LEVEL CLOUDINESS) IS MORE PERSISTENT
THAN EXPECTED THEN HIGHS COULD RUN SEVERAL DEGREES LOWER. I HAVE
TRENDED THE FORECAST TOWARD THE LOWER END OF THE GFS/NAM MOS
ENVELOPE...BUT NOT NEARLY AS COOL AS THE MOST RECENT GFS LAMP MOS
BULLETINS WHICH ARE ONLY SHOWING 82-84 AREA-WIDE.
AS THE ATMOSPHERE MOISTENS AND THE SUBSIDENCE INVERSION BETWEEN
700-550 MB ERODES...SHOWER AND T-STORM CHANCES SHOULD INCREASE LATER
TODAY. THE BEST CHANCE OF AFTERNOON CONVECTION WILL EXIST ACROSS
THE SOUTH CAROLINA PEE DEE REGION PLUS ROBESON COUNTY NC WHERE I
HAVE 30-40 POPS FORECAST. THE COAST SHOULD REMAIN DRY WITH A COOLER
ONSHORE FLOW AND A LATER EROSION OF THE MID-LEVEL CAP. DESPITE
COOLER SURFACE TEMPERATURES TONIGHT I HAVE BROUGHT SHOWER AND
T-STORM CHANCES ALL THE WAY DOWN TO THE COAST AS A FAVORABLY
POSITIONED 200 MB JET ACROSS VIRGINIA ADDS SYNOPTIC LIFT TO AN
ALREADY CONDITIONALLY UNSTABLE AIRMASS. LOWS TONIGHT SHOULD FALL
INTO THE LOWER 70S MOST AREAS...PERHAPS A FEW DEGREES WARMER AT THE
BEACHES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...ACTIVE FIRST HALF OF THE PERIOD AS AN UPPER
IMPULSE ROTATING AROUND ANOMALOUSLY DEEP UPPER TROUGH DRIVES A COLD
FRONT ACROSS THE CAROLINAS. THIS OCCURS IN AN ENVIRONMENT WITH
NEARLY 2 INCH PWATS AND MODERATELY STEEP ML LAPSE RATES...SO
CONVECTION SHOULD BE PRETTY WIDESPREAD...AND WILL BUMP TO LOW-LIKELY
SUNDAY AFTN/EVE. DO NOT ANTICIPATE ANY SEVERE...BUT WITH HIGH PWATS
IN PLACE HEAVY RAIN COULD OCCUR WITHIN ANY TSTM. ACTUAL SURFACE
FRONT WILL NOT MOVE OFFSHORE UNTIL LATE MONDAY...BUT MUCH DRIER AIR
BEGINS TO ADVECT INTO THE AREA AHEAD OF THE SURFACE BOUNDARY. SO
WHILE THERE MAY STILL BE ISOLATED CONVECTION...TYPICAL SUMMERTIME
ACTIVITY...ON MONDAY...IT WILL BE MUCH LESS ACTIVE THAN WHAT OCCURS
ON SUNDAY.
MAX TEMPS BOTH DAYS WILL BE A LITTLE BELOW NORMAL FOR THE END OF
JULY...MID/UPR 80S. LOWS AT NIGHT WILL FALL INTO THE 70-73
RANGE...TYPICAL FOR MID-SUMMER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 PM SATURDAY...BROAD UPPER RIDGING AND A RATHER
NON-DESCRIPT SURFACE PRESSURE PATTERN TO BEGIN THE EXTENDED QUICKLY
CHANGES WED-FRI AS UPPER TROUGH RELOADS ACROSS THE EASTERN CONUS.
TUESDAY MAY END UP THE WARMEST DAY OF THE PERIOD AS BROAD UPPER
RIDGING AND SURFACE HIGH PRESSURE MOVE ACROSS THE AREA. ALTHOUGH AN
ISOLATED DIURNAL TSTM CANNOT BE RULE OUT...WILL CARRY ONLY SCHC AS
ANY COVERAGE WILL BE ISOLATED. TEMPS TUESDAY WILL BE RIGHT AROUND
CLIMO FOR HIGHS AND LOWS.
COLD FRONT APPROACHES LATE TUESDAY BUT APPEARS TO GET HUNG UP OVER
THE AREA. THIS SETS UP A RATHER STRANGE SITUATION FOR MID-SUMMER AS
A BROAD LOW PRESSURE MOVES ACROSS THE SOUTHEAST AND OVER THE
CAROLINAS WED/THU ALONG THIS BOUNDARY. EVEN A WEAK BAROCLINIC LOW
THIS TIME OF YEAR IS ABNORMAL...BUT THIS SEASON HAS BEEN QUITE
ATYPICAL THUS FAR...SO WHY NOT! AT THE VERY LEAST...INCREASING
MOISTURE COMBINED WITH A POTENT VORT ALOFT WILL CAUSE BETTER RAIN
CHANCES WED/THU BEFORE DRYING BEGINS ON FRIDAY. COMBINATION OF
REDUCED MID-LEVEL THICKNESSES AND CLOUDS/RAIN WILL KEEP HIGH TEMPS
BELOW CLIMO WED/THU BEFORE RETURNING TO SEASONABLE LEVELS FRIDAY.
MINS THROUGH THE WEEK WILL AVERAGE A DEGREE OR TWO ABOVE NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...HIGH CONFIDENCE FOG/STRATUS WILL BURN OFF AS ADVERTISED
IN TAFS. VFR EXPECTED THE REMAINDER OF THE MORNING ALTHOUGH CANNOT
RULE OUT A BRIEF MVFR CIG AS CUMULUS DEVELOPS. LOCAL HRRR SUGGESTS
NO CONVECTION AT THE COAST WITH SHOWERS AND THUNDERSTORMS DEVELOPING
NEAR KFLO 20-21Z AND A HOUR OR TWO LATER AT KLBT. THIS IS CONSISTENT
WITH OTHER MODELS. WILL INDICATE VCTS AT KFLO/KLBT DUE TO UNCERTAINTY
WITH TIMING.
THUNDERSTORMS WILL END DURING THE EVENING BUT LIGHT SHOWERS COULD
CONTINUE THROUGH THE OVERNIGHT HOURS. DESPITE BROKEN CLOUD COVER
THERE IS MODERATE CONFIDENCE MVFR/IFR CONDITIONS WILL DEVELOP
AGAIN AT KFLO/KLBT IN THE PRE-DAWN HOURS WITH TEMPO MVFR AT THE
COASTAL TERMINALS.
EXTENDED OUTLOOK...SCATTERED SHOWERS/THUNDERSTORMS SUNDAY AND
MONDAY AS ANOTHER COLD FRONT APPROACHES THE TERMINALS. OTHERWISE
VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...LIGHT EAST WINDS CONTINUE OUT AT THE
OFFSHORE BUOYS AND ALONG THE SOUTH CAROLINA COAST. ALONG THE NC
COAST WHERE ONSHORE WINDS WERE EVEN LIGHTER A LANDBREEZE HAS
DEVELOPED WITH OFFSHORE WIND DIRECTIONS NOTED. WINDS SHOULD AVERAGE
EASTERLY THIS MORNING...TURNING MORE SOUTHEASTERLY TO SOUTHERLY THIS
AFTERNOON WITH A DEVELOPING SEABREEZE. NO SIGNIFICANT CHANGES ARE
NECESSARY. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
BERMUDA HIGH PRESSURE IS CENTERED WELL OFFSHORE...ALMOST IN THE
CENTRAL ATLANTIC...BUT IS STILL DRAWING A SOUTHERLY STREAM OF AIR
NORTHWARD FROM THE CARIBBEAN THROUGH THE WESTERN ATLANTIC. AN OLD
STALLED FRONT IS DISSIPATING OFF THE CAROLINA COAST...BUT SATELLITE
IMAGERY AND NOAA BUOY 41002 BOTH INDICATE A COMPACT LOW HAS
DEVELOPED ABOUT 200 MILES EAST OF CAPE FEAR. THIS LOW IS FORECAST TO
MOVE NORTHEASTWARD TODAY...WITH VERY LITTLE DIRECT IMPACT ON OUR
WEATHER. OUR EASTERLY WINDS THIS MORNING ARE PROBABLY A RESULT OF
THE OFFSHORE LOW...BUT THIS EFFECT SHOULD WANE WITH THE FLOW TURNING
MORE SOUTHERLY WITH TIME. WIND SPEEDS WILL REMAIN 10 KNOTS OR LESS
THROUGH TONIGHT.
A COLD FRONT EXTENDING FROM INDIANA TO MISSOURI WILL MOVE INTO THE
APPALACHIANS BY DAYBREAK SUNDAY. INCREASING MOISTURE AHEAD OF THE
FRONT MAY YIELD ISOLATED SHOWERS AND T-STORMS TONIGHT...BUT WITH
BETTER CHANCES EXPECTED SUNDAY.
AREA BUOYS REPORT SEA HEIGHTS AROUND 2 FEET CURRENTLY. A 9 SECOND
SOUTHEAST SWELL WILL DEVELOP TONIGHT WHICH MAY ADD A FOOT TO SEA
HEIGHTS AWAY FROM SHORE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...LARGE AREA OF HIGH PRESSURE WELL
OFFSHORE...AND A WEAK COLD FRONT SLOWLY MOVING ACROSS THE CAROLINAS
DURING THE SHORT TERM...CREATE A WEAK GRADIENT AND LIGHT WINDS
THROUGH THE EARLY PART OF NEXT WEEK. AHEAD OF THIS FRONT...SW WINDS
WILL BE PREDOMINANT AT AROUND 10 KTS...VEERING TO THE THE WEST AT 10
KTS OR LESS ONLY VERY LATE MONDAY NIGHT. ALTHOUGH THESE WINDS WILL
BE LIGHT...THEY WILL PERSIST FOR A CONSIDERABLE TEMPORAL
PERIOD...THUS DRIVING SEAS TO 2-4 FT EACH DAY. NO SIGNIFICANT SWELL
WILL EXIST WITHIN THE SPECTRUM.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE OFFSHORE AND A
WEAKENING/RESIDUAL BOUNDARY NEAR THE AREA CREATES SOUTHERLY WINDS
WITH LITTLE DIRECTIONAL CHANGE...WITH SPEEDS AROUND 10
KTS...INCREASING TO NEAR 15 KTS LATE WEDNESDAY. SOUTHERLY RETURN
FLOW AROUND OFFSHORE HIGH PRODUCES A 2-3FT/8SEC SE SWELL...WHICH
COMBINES WITH LOW-AMPLITUDE WIND WAVES TO CREATE 2-4 FT SEAS THROUGH
THE PERIOD. LATE TUESDAY AND WEDNESDAY...WEAK BUT MUCH-LONGER PERIOD
SWELL AHEAD OF WEAKENING TROPICAL STORM DORIAN WILL ENTER THE LOCAL
WATERS. ATTM...MAXIMUM SWELL IS FORECAST TO BE 2-3FT/11-12 SEC ON
WEDNESDAY. THIS COULD CREATE SLIGHTLY HIGHER WAVES ACROSS THE WATERS
LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1240 PM CDT SAT JUL 27 2013
.UPDATE...
ISSUED AT 1240 PM CDT SAT JUL 27 2013
FAIR WEATHER CUMULUS FIELD HAS APPEARED FASTER AND A BIT MORE
ROBUST THAN ORIGINALLY FORECAST. HAVE UPPED THE SKY COVER WHICH
MAY ULTIMATELY EFFECT MAX TEMPS...BUT CURRENT FORECAST LOOKS
GOOD. LEFT ANY MENTION OF POPS OUT DESPITE -RASH GETTING CLOSE TO
EASTERN CWFA. 88D ECHOS SHRINKING AND UPSTREAM METARS/RADAR
SHOWING LITTLE WESTWARD PROGRESS ATTM. WILL NEED TO WATCH IT FOR
EVENING THOUGH AS IR SHOWS COOLING TOPS AND HRRR DOES BRUSH LOW
TO WADENA COUNTIES WITH A FEW -RASH AROUND 00Z.
UPDATE ISSUED AT 946 AM CDT SAT JUL 27 2013
MINOR ADJUSTMENTS WERE MADE TO THE TRENDS IN SKY AND TEMPERATURE
TO MATCH REALITY. OTHERWISE CURRENT FORECAST REMAINS ON TRACK.
UPDATE ISSUED AT 650 AM CDT SAT JUL 27 2013
NO CHANGES MADE THIS UPDATE PERIOD.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 325 AM CDT SAT JUL 27 2013
FORECAST CHALLENGE CONCERNS TEMPERATURES AND EARLY NEXT WEEK PCPN
CHANCES. MODEL DIFFERENCES MAINLY WITH TIMING OF FRONTAL BOUNDARY
MONDAY. WILL USE MODEL BLEND.
SURFACE HIGH PRESSURE TO DRIFT SLOWLY EAST ACROSS FA THIS WEEKEND.
CURRENT TEMPERATURES SHOWING BEST POTENTIAL FOR RECORD LOWS ACROSS
NORTHERN FA WHERE TEMPERATURES CURRENTLY IN THE MID 40S. THERMAL
COLUMN WARMS SLIGHTLY TODAY AND CLOUD COVER NOT TO BE QUITE AS
EXTENSIVE AS YESTERDAY. WITH COOL START HOWEVER MAXIMUM
TEMPERATURES LIKELY ONLY TO BE A FEW DEGREES WARMER THAN
YESTERDAY.
WITH SURFACE HIGH OVERHEAD...SKC AND LIGHT WINDS TONIGHT WILL AGAIN
NEED TO MONITOR FOR RECORD LOW TEMPERATURES.
COLUMN CONTINUES TO SLOWLY MODERATE SUNDAY SO WILL SEE SLIGHTLY
WARMER TEMPERATURES BUT STILL WAY BLO AVERAGE.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 325 AM CDT SAT JUL 27 2013
AS HIGH PRESSURE SHIFTS EAST SUNDAY NIGHT WEAK RETURN FLOW AND
WARM ADVECTION SHOULD END THE THREAT OF RECORD LOW TEMPERATURES.
MODELS SHOWING SLIGHT DIFFERENCES IN TIMING OF NEXT COLD FRONT
MONDAY WITH THE NAM THE QUICKEST. MODELS ALSO DIFFER ON RAIN
POTENTIAL IN WARM ADVECTION REGIME AHEAD OF BOUNDARY PASSAGE. FOR
THIS ONLY MADE MINOR ADJUSTMENTS TO POPS. DEPENDING ON CLOUD COVER
TEMPERATURES WILL BE WARMER BUT STILL BLO AVERAGE.
TUESDAY-FRIDAY...BOTH THE 00Z GFS/ECMWF ARE IN AGREEMENT BRINGING
THE WEAK SFC FRONT THROUGH ON TUESDAY...WITH SCATTERED CONVECTION
ALONG AND AHEAD OF IT.
CONFLUENT NORTHWEST FLOW ALOFT IS EXPECTED TO SET UP ACROSS THE
NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK....DOWNSTREAM FROM THE
EASTERN PACIFIC/WESTERN NORTH AMERICA BLOCKING PATTERN. THIS IS
EXPECTED TO LEAD TO A RELATIVELY QUIET PERIOD OF WEATHER
MID-WEEK...WITH WEAK SFC HIGH PRESSURE IN PLACE.
HAVE INCLUDED LOW POPS THUR NIGHT/FRI AS ENERGY FROM THE WESTERN US
UPPER LOW SHIFTS EAST WITH INCREASING ZONAL FLOW INTO THE CENTRAL
PLAINS. HOWEVER...MODELS INDICATE DRY NORTHERLY LOW-LEVEL FLOW
PERSISTING OVER THE AREA. THUS...FORECAST CONFIDENCE IS LOW BY LATE
WEEK.
TEMPERATURES THROUGH THE PERIOD WILL REMAIN NEAR TO A BIT BELOW
NORMAL...WITH HIGHS MAINLY IN THE 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1240 PM CDT SAT JUL 27 2013
VFR TODAY WITH SCT/BKN DECK AOA 5KFT. GUSTS 20 TO 25KTS POSSIBLE IN
THE VALLEY AND AT BJI THRU THE AFTERNOON. SKC DEVELOPING THIS
EVENING AND OVERNIGHT WITH LIGHT AND VARIABLE WINDS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...EWENS
SHORT TERM...VOELKER
LONG TERM...MAKOWSKI/VOELKER
AVIATION...KAISER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
104 AM CDT SAT JUL 27 2013
.UPDATE...
ISSUED AT 1255 AM CDT SAT JUL 27 2013
LITTLE CHANGE TO THE GOING FORECAST. HAVE DROPPED SKY COVER
FORECAST TO ZERO WEST AND POPS TO ZERO ENTIRE FORECAST AREA.
RECORD LOW TEMPERATURES ARE STILL POSSIBLE AROUND
DAYBREAK...ESPECIALLY AT BISMARCK AND JAMESTOWN.
UPDATE ISSUED AT 947 PM CDT FRI JUL 26 2013
HIGH PRESSURE CONTINUES TO SETTLE ACROSS THE NORTHERN PLAINS THIS
EVENING GENERATING LIGHT WINDS AND CLEAR SKIES. TEMPERATURES ARE
STILL EXPECTED TO RADIATE TO RECORD LOWS (LOWER 40S) OVER BISMARCK
AND JAMESTOWN BY EARLY SATURDAY MORNING. SEE TABLE IN THE SHORT
TERM SECTION BELOW FOR FORECAST AND RECORD LOWS FOR OTHER SELECTED
CITIES IN WESTERN AND CENTRAL NORTH DAKOTA.
OTHERWISE...NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST.
THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 657 PM CDT FRI JUL 26 2013
NOT TOO MANY CHANGES WERE MADE TO THE ONGOING FORECAST. ONLY
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
RECORD LOWS STILL LOOK TO BE ON TRACK FOR BISMARCK AND JAMESTOWN
TONIGHT. SEE TABLE IN THE SHORT TERM DISCUSSION BELOW FOR FORECAST
AND RECORD LOWS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 253 PM CDT FRI JUL 26 2013
NO PRECIPITATION FOR THE SHORT TERM PERIOD...WITH THE MAIN
CHALLENGE BEING RECORD COLD TEMPERATURES FOR SATURDAY
MORNING...MAINLY FOR BISMARCK AND JAMESTOWN.
LATEST VISIBLE SATELLITE IMAGERY SHOWS SCT/BKN CUMULUS FIELD
COVERING ALL OF NORTH DAKOTA. CYCLONIC FLOW WITH AN UPSTREAM
SHORTWAVE TROUGH OVER SOUTHERN SASKATCHEWAN WILL MAINTAIN THE
CUMULUS FIELD THROUGH THE EVENING...AND AFTER SUNSET WILL SEE A
GRADUAL REDUCTION IN CLOUDS WITH CLEAR SKIES COMMENCING LATER
TONIGHT. THE SHORTWAVE IS EXPECTED TO MAKE IT TO AROUND STANLEY BY
00Z SATURDAY...THEN INTO THE JAMES RIVER VALLEY BY 06Z SATURDAY.
THE GFS AND TO SOME EXTENT THE RAP AND HRRR TRY TO DEVELOP A
COUPLE SHOWERS IN THE SOUTHWEST AND ALSO IN THE NORTHEAST/TURTLE
MOUNTAINS THIS AFTERNOON...BUT HAVE OPTED TO KEEP IT DRY WITH
REGIONAL RADAR AND SURFACE OBSERVATIONS CONTINUING TO SHOW A VOID
IN ANY PRECIPITATION DEVELOPMENT UP TO THIS POINT. A 1030MB
SURFACE HIGH PRESSURE OVER SOUTHEASTERN SASKATCHEWAN WILL ALSO
SHIFT SOUTHEAST INTO EAST CENTRAL NORTH DAKOTA...AND INTO THE
LOWER JAMES RIVER VALLEY BY 12Z SATURDAY. UPSTREAM LOW
TEMPERATURES IN SOUTH CENTRAL CANADA FRIDAY MORNING RANGED FROM
38F TO 42F...WHICH IS IN THE BALLPARK OF WHAT THE MET/MAV GUIDANCE
IS FOR CENTRAL NORTH DAKOTA. THE OLD RULE OF THUMB USING THE
MINIMUM DEWPOINT DURING THE MAX TEMPERATURE FOR OBTAINING AN
APPROXIMATE LOW TEMPERATURE ALSO SUPPORTS LOWS BETWEEN 39F AND
44F. CONFIDENCE IS HIGH FOR RECORD LOWS IN BISMARCK AND
JAMESTOWN...WITH MINOT...WILLISTON...AND DICKINSON COMING JUST SHY
OF ESTABLISHING NEW RECORD LOWS.
RECORD LOW TEMPERATURES FOR SATURDAY JULY 27 ARE AS FOLLOWS...
CITY RECORD LOW/DATE FORECAST LOW TEMP
BISMARCK 43F/1994 41F
JAMESTOWN 44F/1904 41F
MINOT 40F/1925 42F
WILLISTON 40F/1908 43F
DICKINSON 40F/1971 43F
CONSIDERING THE LOCATION OF THE SURFACE HIGH...EAST CENTRAL NORTH
DAKOTA AND INTO THE SOUTHERN JAMES RIVER VALLEY...THIS IS THE
OPTIMAL LOCATION FOR OBTAINING THE COLDEST TEMPERATURES ACROSS
SOUTH CENTRAL NORTH DAKOTA...BISMARCK AND JAMESTOWN. UPSTREAM
OBSERVATIONS IN SOUTH CENTRAL CANADA ALSO HAD SOME PATCHY FOG FRIDAY
MORNING AND HAVE ADDED THAT TO THE FORECAST...MAINLY ALONG AND
JUST EAST OF HIGHWAY 83.
FOR SATURDAY...SUNNY WEST...AND MOSTLY SUNNY SKIES CENTRAL.
EXPECT MID TO LATE MORNING CUMULUS AGAIN DEVELOPING OVER CENTRAL
NORTH DAKOTA WITH WEAK CYCLONIC FLOW...BUT SOUNDINGS SHOW DRY
AIR/SUBSIDENCE ALOFT WILL BECOME MUCH STRONGER..AND THIS WILL
INHIBIT ANY FURTHER BUILD UPS FOR THE AFTERNOON. THE RESULT WILL
BE A SCATTERED FAIR WEATHER CUMULUS FIELD EARLY ON...THEN
DISSIPATING THROUGH THE AFTERNOON. AFTERNOON HIGHS AROUND 70F
CENTRAL TO THE MID 70S WEST.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 253 PM CDT FRI JUL 26 2013
WE TRANSITION FROM A COOL AND DRY PERIOD BACK TO A WARMER AND
ACTIVE PERIOD FOR THE BEGINNING OF THE LONG TERM PERIOD.
AFTERWARDS...A RETURN TO A RELATIVELY QUIET PERIOD IS EXPECTED
THROUGH THE MIDDLE PORTIONS OF THE WORK WEEK UNTIL LATER NEXT WEEK
WHEN WE MAY SEE INCREASING CHANCES FOR MORE WIDESPREAD
PRECIPITATION.
RETURN FLOW INCREASES OVER WESTERN NORTH DAKOTA SATURDAY NIGHT AS
SURFACE HIGH PRESSURE SLOWLY MOVES EAST TOWARDS THE UPPER
MISSISSIPPI VALLEY...AND A SFC TROUGH DEVELOPS IN THE LEE OF THE
MONTANA ROCKIES AHEAD OF A LONG WAVE TROUGH MOVING INTO ALBERTA.
LATEST 12Z MODELS HAVE AGAIN SLOWED DOWN THE EASTWARD PROGRESSION
OF THE SURFACE TROUGH OVER EASTERN MONTANA...AND NOW KEEP ALL
PRECIPITATION OFF TO OUR WEST THROUGH SUNDAY MORNING. AS A RESULT
I HAVE REMOVED ALL MENTION OF THUNDERSTORMS THROUGH 18Z SUNDAY.
SHORT WAVE MID LEVEL RIDGE MOVING ACROSS THE REGION ON SUNDAY WILL
BRING WARMER AIR TO WEST AND CENTRAL NORTH DAKOTA...WITH DAYTIME
HIGHS WARMING BACK TOWARDS THE 80 DEGREE MARK WEST AND MID TO
UPPER 70S CENTRAL. WE START TO SEE INCREASING INSTABILITY OVER THE
FAR WESTERN COUNTIES SUNDAY AFTERNOON AS RETURN FLOW CONTINUES
HELPING LOW LEVEL MOISTURE MOVE BACK INTO THE NORTHERN PLAINS.
WHILE I HAVE KEPT SOME MENTION FOR AFTERNOON CONVECTION IN THE
FORECAST ACROSS THE WEST...12Z NAM/GFS BUFFER SOUNDINGS INDICATE
WE WILL BE STRONGLY CAPPED SO WILL CONSIDER TRENDING SUNDAY
AFTERNOON DRY WITH FUTURE FORECAST PACKAGES.
AS THE RIDGE CONTINUES EASTWARD...FLOW ALOFT WILL TRANSITION TO MORE
WEST/SOUTHWESTERLY SUNDAY NIGHT THROUGH MONDAY AND INTO MONDAY NIGHT
ALONG WITH FAVORABLY INSTABILITY FOR THUNDERSTORMS SPREADING ACROSS
THE STATE. COMBINED WITH THE SURFACE TROUGH PUSHING EAST ACROSS THE
DAKOTAS...EXPECT TO SEE A RATHER ACTIVE CONVECTIVE PERIOD FROM
LATE SUNDAY NIGHT THROUGH MONDAY EVENING. AS FAR AS SEVERE
WEATHER...LINGERING CLOUDS FROM SUNDAY NIGHTS EXPECTED CONVECTION
COULD VERY WELL LIMIT THE SEVERE POTENTIAL...FOR MONDAY.
HOWEVER...LATEST MODELS ARE NOW INCREASING THE POTENTIAL FOR
SCATTERED STRONG TO SEVERE STORMS...ESPECIALLY MONDAY
AFTERNOON/EVENING. WILL MENTION THIS POSSIBILITY IN THE HWO. IT
SHOULD BE NOTED THE 12Z NAM...WHILE A FAST OUTLIER...WOULD FAVOR
THE MOST ACTIVE PERIOD LATE SUNDAY EVENING THROUGH MONDAY
AFTERNOON. THUS WILL NEED TO KEEP AN EYE ON THE MODEL TRENDS THE
NEXT FEW PERIODS.
AFTER THIS SHORT PERIOD OF ACTIVE WEATHER...MODELS FORECAST A RETURN
TO A QUIETER WEATHER PERIOD TUESDAY INTO MID-WEEK WITH NORTHWEST
FLOW ALOFT REDEVELOPING FOLLOWED BY ANOTHER S/WV RIDGE. WHILE CANNOT
RULE OUT ISOLATED SHOWERS/THUNDERSTORMS...THE OVERALL PATTERN
TUESDAY-THURSDAY WOULD NOT SUPPORT WIDESPREAD PRECIPITATION. AS WE
PROCEED TOWARDS THE END OF THE WORK WEEK INTO THE FOLLOWING
WEEKEND...BOTH THE 12Z GFS/ECMWF DEPICT ANOTHER ACTIVE WEATHER
PERIOD DEVELOPING AS FLOW BECOMES QUASI-ZONAL AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY) ISSUED AT 1255
AM CDT SAT JUL 27 2013
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD. A FEW TO SCATTERED
CLOUDS COULD WORK INTO KMOT AND KJMS BEFORE DAYBREAK. WINDS WILL
CONTINUE TO GRADUALLY VEER TO EASTERLY/SOUTHEASTERLY THROUGH THE
PERIOD AS HIGH PRESSURE CRESTS ACROSS THE REGION.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...KS
LONG TERM...NH
AVIATION...JPM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
324 PM EDT SAT JUL 27 2013
.SYNOPSIS...
COLD FRONT TONIGHT. HIGH PRESSURE BUILDS BACK SUNDAY INTO MONDAY.
DISTURBANCE LATE TUESDAY...WITH PEAK SUPPORT TO OUR SOUTH.
&&
.NEAR TERM /THROUGH SUNDAY/...
SOME CLEARING AND HEATING OVER THE WEST VIRGINIA LOWLANDS
REALIZING SOME CAPE WITH SOME TALLER CELLS AND A LITTLE BIT OF
LIGHTNING NOW TO BE FOUND IN THE CONVECTION IN THIS AREA. VORT MAX
HAS BEEN A BIT LESS EFFECTIVE THAN EXPECTED IN TERMS OF COVERAGE
OF SHOWERS OVER THE TRI STATE AREA INTO SOUTHEAST OHIO...AND
TRENDED THESE POPS DOWNWARD THROUGH THE REMAINDER OF THE AFTERNOON
BEFORE BRINGING THEM BACK TO LIKELY WITH THE COLD FRONT. FEEL THE
BEST GUIDANCE OUT THERE RIGHT NOW IS THE HRRR AND THE LOCAL WRF
MODELS...AND LEAN ON THESE THROUGH TE 12Z TIME FRAME. REMOVE
THUNDER CHANCES LATE THIS EVENING...BUT THAT TIMING THAT LATE MAY
STILL BE TOO GENEROUS IN THAT SENSE.
POST FRONTAL ENVIRONMENT WILL NOT CLEAR OUT QUICKLY. HIDDEN IN THE
LOW LEVELS WILL BE A BAND OF MOISTURE AND A RESULTANT LOW LEVEL
STRATUS DECK. THIS SHOULD ERODE WEST TO EAST THROUGH THE LOWLANDS
BY EVENING...BUT LINGER IN THE MOUNTAINS BEYOND 00Z MONDAY.
CLOUDS WILL KEEP THE TEMPERATURES IN THE 60S IN THE NORTHEAST
MOUNTAINS SUNDAY...AND MID 70S FOR THE MOST PART OVER THE
LOWLANDS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
UPPER LOW OVER THE GREAT LAKES WILL SLOWLY LIFT OUT BY
TUESDAY...WITH NORTHWEST FLOW ALOFT BACKING TO A MORE WESTERLY
DIRECTION. THIS WILL ALLOW A SIGNIFICANT SHORT WAVE AND SURFACE LOW
TO TRACK EASTWARD ALONG THE SOUTHERN EDGE OF THE WESTERLIES INTO THE
MID AND LOWER MISSISSIPPI VALLEY TUESDAY. ALL THE MODELS LATCH ONTO
THIS SYSTEM...BUT THERE ARE DIFFERENCES IN THE EXACT TRACK...
TIMING...AND QPF. THIS IS DUE TO HOW MUCH THE FLOW ACTUALLY BACKS
AHEAD OF THE APPROACHING SYSTEM. THERE IS REALLY NO MODEL CONSENSUS
TO EXUDE HIGH CONFIDENCE...SO WILL BASICALLY GO WITH PERSISTENCE ON
OUR FORECAST...AND FOCUS HIGHEST POPS AND QPF ACROSS THE SOUTH HALF
OF THE AREA...WITH THE LEADING EDGE OF THE PRECIP SHIELD TO ARRIVE
AS SOON AS LATER TUESDAY NIGHT. UNTIL THEN...DRY HIGH PRESSURE WITH
MODERATE TEMPERATURES AND HUMIDITY WILL MAKE MONDAY...AND EVEN INTO
TUESDAY... A RATHER TRANQUIL AND UNOPPRESSIVE PERIOD WITH
TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
SHORT WAVE AND LOW PRESSURE WILL CONTINUE MOVING EASTWARD MID WEEK
ACROSS THE OHIO AND TENNESSEE VALLEYS...WITH THE HIGHEST POPS AND
QPF WEDNESDAY AND WEDNESDAY NIGHT. AGAIN...WILL FOCUS ON A MORE
SOUTHERN IMPACT GIVEN UNCERTAINTY IN THE EXACT TRACK AND WITH ANY
ONGOING CONVECTIVE COMPLEXES TENDING TO SINK SOUTH AND EAST. WILL
LINGER POPS INTO THURSDAY MAINLY IN THE MOUNTAINS...BUT HIGH
PRESSURE WILL BUILD IN BY LATER THURSDAY WITH DRIER
WEATHER...MODERATE TEMPERATURES AND HUMIDITIES RETURNING THROUGH
FRIDAY. SATURDAY WILL LIKELY SEE ANOTHER SYSTEM APPROACHING FOR A
POSSIBLE WET WEEKEND. AGAIN...TEMPERATURES ARE EXPECTED TO BE NEAR
NORMAL.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
NUMEROUS SHOWERS WITH A FEW THUNDERSTORMS POSSIBLE AHEAD OF A
STRONG COLD FRONT TODAY. CHANCES FOR SHOWERS CONTINUE INTO TONIGHT
WITH THE COD FRONT ITSELF.
THROUGH THE REMAINDER OF TODAY...SOME CLEARING OVER THE WESTERN
LOWLANDS HAS ALLOWED THE CAPE TO SPIKE...AND NOW ARE SEEING A
COUPLE LIGHTNING STRIKES IN THE NORTH CENTRAL PART OF WEST
VIRGINIA. NO PREVAILING TSRA FOR THE TERMINALS...JUST USING
VCTS/CB THROUGH EVENING.
CARRYING A TEMPO IFR OFF THE BAT FOR EKN IN STEADIER RAIN WITH
PREVAILING MVFR VISIBILITIES.
EXPECTING A LOW STRATUS DECK TO MATERIALIZE BEHIND THE FRONT
SUNDAY...WITH MVFR CEILINGS POSSIBLE BENEATH THE ELEVATED
INVERSION LAYER. STILL MAY HAVE TO DODGE A SHOWER OR TWO SOUTHEAST
OF THE OHIO RIVER EARLY SUNDAY. LOW STRATUS DECK ERODES AFTER 18Z
FOR THE LOWLANDS...BUT COULD LINGER IN THE MOUNTAINS INTO SUNDAY
EVENING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: MAY NEED A FEW MORE TEMPO AMENDMENTS IN
SHRA/TSRA TODAY. TIMING OF COLD FRONT AND ENDING SHOWERS MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY H H M H H H H H H H H H
EKN CONSISTENCY H H M M M M H H H H H M
PKB CONSISTENCY H M M H H M M M M H H H
CKB CONSISTENCY H H H M M M H H H H H H
AFTER 18Z SUNDAY...
IFR IN VALLEY FOG MONDAY AND TUESDAY MORNINGS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...26
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
230 PM EDT SAT JUL 27 2013
.SYNOPSIS...
COLD FRONT TONIGHT. HIGH PRESSURE BUILDS BACK SUNDAY INTO MONDAY.
DISTURBANCE LATE TUESDAY...WITH PEAK SUPPORT TO OUR SOUTH.
&&
.NEAR TERM /THROUGH SUNDAY/...
SOME CLEARING AND HEATING OVER THE WEST VIRGINIA LOWLANDS
REALIZING SOME CAPE WITH SOME TALLER CELLS AND A LITTLE BIT OF
LIGHTNING NOW TO BE FOUND IN THE CONVECTION IN THIS AREA. VORT MAX
HAS BEEN A BIT LESS EFFECTIVE THAN EXPECTED IN TERMS OF COVERAGE
OF SHOWERS OVER THE TRI STATE AREA INTO SOUTHEAST OHIO...AND
TRENDED THESE POPS DOWNWARD THROUGH THE REMAINDER OF THE AFTERNOON
BEFORE BRINGING THEM BACK TO LIKELY WITH THE COLD FRONT. FEEL THE
BEST GUIDANCE OUT THERE RIGHT NOW IS THE HRRR AND THE LOCAL WRF
MODELS...AND LEAN ON THESE THROUGH TE 12Z TIME FRAME. REMOVE
THUNDER CHANCES LATE THIS EVENING...BUT THAT TIMING THAT LATE MAY
STILL BE TOO GENEROUS IN THAT SENSE.
POST FRONTAL ENVIRONMENT WILL NOT CLEAR OUT QUICKLY. HIDDEN IN THE
LOW LEVELS WILL BE A BAND OF MOISTURE AND A RESULTANT LOW LEVEL
STRATUS DECK. THIS SHOULD ERODE WEST TO EAST THROUGH THE LOWLANDS
BY EVENING...BUT LINGER IN THE MOUNTAINS BEYOND 00Z MONDAY.
CLOUDS WILL KEEP THE TEMPERATURES IN THE 60S IN THE NORTHEAST
MOUNTAINS SUNDAY...AND MID 70S FOR THE MOST PART OVER THE
LOWLANDS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
OVERALL QUIETER AND COOLER WEATHER IN THE SHORT TERM PERIOD. COLD
FRONT WILL BE TO THE EAST OF THE CWA SUNDAY MORNING...WITH UPPER
TROUGH ACROSS THE EASTERN U.S....AND SURFACE HIGH PRESSURE GRADUALLY
TRYING TO PUSH IN FROM THE WEST. WILL STILL BE SOME CLOUDS LINGERING
OVER EASTERN COUNTIES EARLY SUNDAY...BUT AT LEAST SOUTHEAST OHIO
ZONES SHOULD SEE SOME PARTIAL CLEARING. MUCH DRIER AIR WILL BEGIN TO
FILTER IN BEHIND THE FRONT...WITH DEW POINTS DIPPING INTO THE LOWER
50S TO UPPER 40S SUNDAY INTO MONDAY. WITH THE CLEAR SKY EXPECTED
OVERNIGHT SUNDAY INTO MONDAY...ALONG WITH CALM SURFACE WINDS AND THE
DRIER AIR IN PLACE...KEPT LOW TEMPERATURES MONDAY MORNING BELOW
GUIDANCE...WITH MANY LOWLANDS DIPPING INTO THE 50S. HOWEVER...FOG
DEVELOPMENT WILL BE LIKELY THAT MORNING...WHICH COULD MITIGATE THE
COOLING SOMEWHAT...THUS LEADING TO A POTENTIAL FOR A BUSTED LOW
TEMPERATURE FORECAST MONDAY MORNING.
UPPER TROUGH AND SURFACE HIGH WILL SLIDE OFF TO THE EAST MONDAY INTO
TUESDAY...AS THE NEXT SYSTEM APPROACHES FROM THE WEST. WITH THE FLOW
TURNING MORE SOUTHERLY...EXPECT WARMER TEMPERATURES AND MORE HUMID
AIR MOVING INTO THE REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ZONAL FLOW MARKS THE BEGINNING OF THE EXTENDED PERIOD WITH A WEAK
IMPULSE POISED TO MOVE THROUGH CWA DAYS 4 AND 5. KEEPING HIGH CHC
POPS ASSOCIATED WITH THIS IMPULSE AS THERE IS NOT ENOUGH CONFIDENCE
IN THE TIMING OR TRACK OF THIS WAVE. 00Z ECMWF IS A BIT SLOWER AND
FURTHER SOUTH THAN THE 06Z AND 12Z GFS RUNS...HOWEVER...THE 12Z GFS
IS HEDGING FURTHER SOUTH PASSING THE H5 VORT THROUGH CENTRAL KY AND
ERN TN. ENOUGH MOISTURE FROM THE UPPER SYSTEM TO THE NORTH WILL
SHOULD ALLOW FOR AT LEAST A SLIGHT CHC OF SHOWERS AND MAYBE EVEN
THUNDER DAY 6. OTHERWISE...A MOSTLY DRY AND SEASONABLE EXTENDED
PERIOD IN OUR NECK OF THE WOODS.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
NUMEROUS SHOWERS WITH A FEW THUNDERSTORMS POSSIBLE AHEAD OF A
STRONG COLD FRONT TODAY. CHANCES FOR SHOWERS CONTINUE INTO TONIGHT
WITH THE COD FRONT ITSELF.
THROUGH THE REMAINDER OF TODAY...SOME CLEARING OVER THE WESTERN
LOWLANDS HAS ALLOWED THE CAPE TO SPIKE...AND NOW ARE SEEING A
COUPLE LIGHTNING STRIKES IN THE NORTH CENTRAL PART OF WEST
VIRGINIA. NO PREVAILING TSRA FOR THE TERMINALS...JUST USING
VCTS/CB THROUGH EVENING.
CARRYING A TEMPO IFR OFF THE BAT FOR EKN IN STEADIER RAIN WITH
PREVAILING MVFR VISIBILITIES.
EXPECTING A LOW STRATUS DECK TO MATERIALIZE BEHIND THE FRONT
SUNDAY...WITH MVFR CEILINGS POSSIBLE BENEATH THE ELEVATED
INVERSION LAYER. STILL MAY HAVE TO DODGE A SHOWER OR TWO SOUTHEAST
OF THE OHIO RIVER EARLY SUNDAY. LOW STRATUS DECK ERODES AFTER 18Z
FOR THE LOWLANDS...BUT COULD LINGER IN THE MOUNTAINS INTO SUNDAY
EVENING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: MAY NEED A FEW MORE TEMPO AMENDMENTS IN
SHRA/TSRA TODAY. TIMING OF COLD FRONT AND ENDING SHOWERS MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H M M M
HTS CONSISTENCY H H H H H H H H M M H H
BKW CONSISTENCY H H H H H H H H H H M M
EKN CONSISTENCY H H H H M H H H M M H H
PKB CONSISTENCY H H H H H M M M M M H M
CKB CONSISTENCY H H H H H H H H H H M M
AFTER 18Z SUNDAY...
IFR IN VALLEY FOG MONDAY AND TUESDAY MORNINGS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...26
SHORT TERM...SL
LONG TERM...TAX
AVIATION...26
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
649 AM EDT SAT JUL 27 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH EAST ACROSS THE REGION THROUGH
TONIGHT. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY
ON SUNDAY WHILE AN UPPER LEVEL LOW SPINS ACROSS THE GREAT LAKES.
THE UPPER LEVEL LOW WILL MOVE SLOWLY NORTHEAST THROUGH MONDAY
WHILE THE SURFACE HIGH EXPANDS ACROSS AREA. TEMPERATURES WILL BE
BELOW NORMAL THROUGH THE BEGINNING OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MODELS ARE IN GREAT AGREEMENT THIS MORNING. HAVE USED THE RAP AND
HRRR FOR TIMING OF PCPN.
AS WAS ADVERTISED YESTERDAY...A PIECE OF ENERGY IS BEING DRAWN NE
ACRS THE OHIO VALLEY THIS MORNING WHILE AN UPR LVL CLOSED LOW SLOWLY
ROTATES SOUTHWARD ACRS THE WRN GREAT LAKES. THIS ENERGY WILL
COMBINE WITH SOME LOW TO MID LVL FORCING OUT AHEAD OF A COLD
FRONT TO BRING WIDESPREAD SHOWERS TO MUCH OF THE REGION DURING THE
MORNING HOURS. INSTABILITY IS WEAK ENOUGH THAT THUNDER IS NOT
ANTICIPATED. FOR THIS AFTERNOON...THE COLD FRONT WILL PUSH EAST
INTO THE WRN CWFA WHILE WIDESPREAD PCPN PUSHES TO THE EAST. THERE
COULD BE A GAP BETWEEN DEVELOPMENTAL PCPN ALONG/AHEAD OF THE FRONT
VERSUS DEPARTING WIDESPREAD PCPN. WE SHOULD SEE ENOUGH DAYTIME
HEATING TO ALLOW FOR A LITTLE MORE INSTABILITY THIS AFTN FOR A
MENTION OF THUNDER. GIVEN PWATS OF 1.75 INCHES...SOME OF THE
SHOWERS MAY BE MODERATE TO LOCALLY HEAVY.
CLOUDS AND PCPN WILL HOLD TEMPERATURES DOWN. HIGHS IN THE LOWER TO
MID 70S STILL LOOK REASONABLE WHICH ARE ABOUT 10 DEGREES BELOW
NORMAL FOR LATE JULY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
S/WV ENERGY ROTATING SE INTO THE REGION AROUND UPR LVL CLOSED LOW
WILL PUSH THE COLD FRONT EAST OF THE AREA OVERNIGHT. THE THREAT OF
SHOWERS/ISOLATED STORMS WILL COME TO AN END THIS EVENING THROUGH
EARLY MORNING...FOLLOWED BY SOME CLEARING IN THE DRY SLOT BEHIND
THE FRONT. MODELS CONTINUE TO ADVERTISE SOME COOL AIR OVERNIGHT...
ESPECIALLY WEST WHERE DRIER AIR AND BETTER CLEARING WILL OCCUR.
RECORD LOWS TONIGHT ARE 50 AT CMH...54 AT DAY AND 53 AT CVG. DAY
AND CVG HAVE THE BEST CHANCE OF EITHER TYING OR BREAKING THEIR
RECORD LOWS. WILL RANGE LOWS FROM NEAR 50 WEST TO THE UPPER 50S
EAST.
UPR LVL CLOSED LOW WILL MOVE SLOWLY EAST ACRS THE WRN/CNTRL GREAT
LAKES AREA ON SUNDAY WHILE A RIDGE OF HIGH PRESSURE BUILDS INTO
THE OHIO VALLEY. CAA IN THE WAKE OF THE FRONT WILL RESULT IN SOME
SCT-BKN CUMULUS CLOUDS. CLOUDS SHOULD BE MOST NUMEROUS ACRS THE
FAR NW WHERE EMBEDDED S/WV ENERGY ROTATING AROUND THE LOW COMBINED
WITH WEAK DIURNAL INSTABILITY MAY RESULT IN A FEW SPOTTY SHOWERS
DURING THE AFTN AND EARLY EVENING. HIGHS ON SUNDAY WILL BE UNSEASONABLY
COOL RANGING FROM THE LOWER TO MID 70S. THESE VALUES WILL BE CLOSE
TO RECORD LOW MAXES FOR THE DATE.
FOR SUNDAY NIGHT INTO MONDAY...MOSTLY CLEAR NIGHT/MOSTLY SUNNY
DAY AS HIGH PRESSURE EXPANDS ACRS THE REGION WHILE UPR LVL CLOSED
LOW MOVES OFF TO THE EAST. TEMPERATURES WILL MODIFY SLIGHTLY INTO
THE MID AND UPPER 70S.
FOR THE PERIOD MONDAY NIGHT INTO TUESDAY NIGHT...HIGH PRESSURE
WILL MOVE EAST. MODELS SUGGEST THAT A SLOW MOVING LOW PRESSURE
SYSTEM WILL MOVE TOWARD THE OHIO VALLEY REGION FROM THE CNTRL/SRN
PLAINS. THE APPROACH OF THIS SYSTEM WILL BRING AN INCREASING
CHANCE FOR PCPN...MAINLY FOR LOCATIONS ALONG AND SOUTH OF THE OHIO
RIVER. OVERNIGHT LOWS WILL MODIFY WITH INCREASING CLOUDS. HIGHS
ON TUESDAY WILL RANGE FROM THE UPPER 70S TO AROUND 80 DEGREES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
MODELS HAVE SLOWED ON AFOREMENTIONED LOW PRESSURE SYSTEM...SO PCPN
WILL LINGER INTO WEDNESDAY...MAINLY ALONG AND SOUTH OF THE OHIO
RIVER. ON THURSDAY...A SYSTEM EAST OF THE AREA WILL BRING A CHANCE
FOR SHOWERS AND THUNDERSTORMS TO EASTERN PORTIONS OF THE REGION.
BY THURSDAY NIGHT AND CONTINUING INTO FRIDAY...HIGH PRESSURE WILL
BRING DRY CONDITIONS BACK TO THE REGION. THERE WILL BE A SLIGHT
WARMING TREND IN TEMPERATURES THROUGH THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
LARGE AREA OF LIGHT RAIN WITH SCATTERED EMBEDDED HEAVIER SHOWERS
ARE MOVING NORTHEASTWARD ACROSS THE AREA IN ADVANCE OF APPROACHING
COLD FRONT. AREA OF RAIN IS MOVING A LITTLE FASTER THAN EARLIER
FORECAST AND SHOULD BE GENERALLY EAST OF THE TAFS BETWEEN 14 TO
15Z. HOWEVER, SHOWERS WITH ISOLATED THUNDERSTORMS ARE EXPECTED TO
DEVELOP BEHIND THIS RAIN AREA STARTING AROUND 13Z. THE THREAT OF
THUNDERSTORMS END WITH THE PASSAGE OF THE FRONT WHICH WILL BE 17Z
FOR KCVG AND KDAY AND 19Z FOR KCMH. WHILE MOST OF THE
PRECIPITATION WILL PRODUCE WIDESPREAD MVFR THERE WILL BE BRIEF
PERIODS OF IFR DUE TO VSBY IN THE HEAVIER SHOWERS AND THUNDERSTORMS.
ALSO IT SHOULD NOTED FROM THE LAST AVIATION DISCUSSION THAT IFR
CONDITIONS ASSOCIATED WITH CIGS HAVE BEGAN TO DEVELOP JUST TO THE
WEST AND NORTH OF KDAY. KDAY FORECAST HAS BEEN UPDATED TO REFLECT
THIS THREAT.
BEHIND THE FRONT LOW LEVEL DRY AIR WILL BE SLOW TO PUSH IN
ALLOWING FOR SCATTERED SHOWERS AND OCCASIONAL MVFR CIGS LASTING
THROUGH THE AFTERNOON AND INTO THE EVENING BEFORE THEY DISSIPATE.
HOWEVER, MID LEVEL MOISTURE IS EXPECTED TO BE SLOW TO RETREAT FROM
THE AREA SO MID LEVEL CLOUDS ARE CURRENTLY EXPECTED TO PERSIST
THROUGH MOST OF THE NIGHTTIME HOURS.
IN ADVANCE OF THE FRONT SURFACES WINDS WILL BE SOUTHWEST 5-12KT
BECOMING NORTHWEST AROUND 10 -15KT BEHIND THE FRONT.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/NOVAK
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
421 AM EDT SAT JUL 27 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH EAST ACROSS THE REGION THROUGH
TONIGHT. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE OHIO VALLEY
ON SUNDAY WHILE AN UPPER LEVEL LOW SPINS ACROSS THE GREAT LAKES.
THE UPPER LEVEL LOW WILL MOVE SLOWLY NORTHEAST THROUGH MONDAY
WHILE THE SURFACE HIGH EXPANDS ACROSS AREA. TEMPERATURES WILL BE
BELOW NORMAL THROUGH THE BEGINNING OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MODELS ARE IN GREAT AGREEMENT THIS MORNING. HAVE USED THE RAP AND
HRRR FOR TIMING OF PCPN.
AS WAS ADVERTISED YESTERDAY...A PIECE OF ENERGY IS BEING DRAWN NE
ACRS THE OHIO VALLEY THIS MORNING WHILE AN UPR LVL CLOSED LOW SLOWLY
ROTATES SOUTHWARD ACRS THE WRN GREAT LAKES. THIS ENERGY WILL
COMBINE WITH SOME LOW TO MID LVL FORCING OUT AHEAD OF A COLD
FRONT TO BRING WIDESPREAD SHOWERS TO MUCH OF THE REGION DURING THE
MORNING HOURS. INSTABILITY IS WEAK ENOUGH THAT THUNDER IS NOT
ANTICIPATED. FOR THIS AFTERNOON...THE COLD FRONT WILL PUSH EAST
INTO THE WRN CWFA WHILE WIDESPREAD PCPN PUSHES TO THE EAST. THERE
COULD BE A GAP BETWEEN DEVELOPMENTAL PCPN ALONG/AHEAD OF THE FRONT
VERSUS DEPARTING WIDESPREAD PCPN. WE SHOULD SEE ENOUGH DAYTIME
HEATING TO ALLOW FOR A LITTLE MORE INSTABILITY THIS AFTN FOR A
MENTION OF THUNDER. GIVEN PWATS OF 1.75 INCHES...SOME OF THE
SHOWERS MAY BE MODERATE TO LOCALLY HEAVY.
CLOUDS AND PCPN WILL HOLD TEMPERATURES DOWN. HIGHS IN THE LOWER TO
MID 70S STILL LOOK REASONABLE WHICH ARE ABOUT 10 DEGREES BELOW
NORMAL FOR LATE JULY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
S/WV ENERGY ROTATING SE INTO THE REGION AROUND UPR LVL CLOSED LOW
WILL PUSH THE COLD FRONT EAST OF THE AREA OVERNIGHT. THE THREAT OF
SHOWERS/ISOLATED STORMS WILL COME TO AN END THIS EVENING THROUGH
EARLY MORNING...FOLLOWED BY SOME CLEARING IN THE DRY SLOT BEHIND
THE FRONT. MODELS CONTINUE TO ADVERTISE SOME COOL AIR OVERNIGHT...
ESPECIALLY WEST WHERE DRIER AIR AND BETTER CLEARING WILL OCCUR.
RECORD LOWS TONIGHT ARE 50 AT CMH...54 AT DAY AND 53 AT CVG. DAY
AND CVG HAVE THE BEST CHANCE OF EITHER TYING OR BREAKING THEIR
RECORD LOWS. WILL RANGE LOWS FROM NEAR 50 WEST TO THE UPPER 50S
EAST.
UPR LVL CLOSED LOW WILL MOVE SLOWLY EAST ACRS THE WRN/CNTRL GREAT
LAKES AREA ON SUNDAY WHILE A RIDGE OF HIGH PRESSURE BUILDS INTO
THE OHIO VALLEY. CAA IN THE WAKE OF THE FRONT WILL RESULT IN SOME
SCT-BKN CUMULUS CLOUDS. CLOUDS SHOULD BE MOST NUMEROUS ACRS THE
FAR NW WHERE EMBEDDED S/WV ENERGY ROTATING AROUND THE LOW COMBINED
WITH WEAK DIURNAL INSTABILITY MAY RESULT IN A FEW SPOTTY SHOWERS
DURING THE AFTN AND EARLY EVENING. HIGHS ON SUNDAY WILL BE UNSEASONABLY
COOL RANGING FROM THE LOWER TO MID 70S. THESE VALUES WILL BE CLOSE
TO RECORD LOW MAXES FOR THE DATE.
FOR SUNDAY NIGHT INTO MONDAY...MOSTLY CLEAR NIGHT/MOSTLY SUNNY
DAY AS HIGH PRESSURE EXPANDS ACRS THE REGION WHILE UPR LVL CLOSED
LOW MOVES OFF TO THE EAST. TEMPERATURES WILL MODIFY SLIGHTLY INTO
THE MID AND UPPER 70S.
FOR THE PERIOD MONDAY NIGHT INTO TUESDAY NIGHT...HIGH PRESSURE
WILL MOVE EAST. MODELS SUGGEST THAT A SLOW MOVING LOW PRESSURE
SYSTEM WILL MOVE TOWARD THE OHIO VALLEY REGION FROM THE CNTRL/SRN
PLAINS. THE APPROACH OF THIS SYSTEM WILL BRING AN INCREASING
CHANCE FOR PCPN...MAINLY FOR LOCATIONS ALONG AND SOUTH OF THE OHIO
RIVER. OVERNIGHT LOWS WILL MODIFY WITH INCREASING CLOUDS. HIGHS
ON TUESDAY WILL RANGE FROM THE UPPER 70S TO AROUND 80 DEGREES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
MODELS HAVE SLOWED ON AFOREMENTIONED LOW PRESSURE SYSTEM...SO PCPN
WILL LINGER INTO WEDNESDAY...MAINLY ALONG AND SOUTH OF THE OHIO
RIVER. ON THURSDAY...A SYSTEM EAST OF THE AREA WILL BRING A CHANCE
FOR SHOWERS AND THUNDERSTORMS TO EASTERN PORTIONS OF THE REGION.
BY THURSDAY NIGHT AND CONTINUING INTO FRIDAY...HIGH PRESSURE WILL
BRING DRY CONDITIONS BACK TO THE REGION. THERE WILL BE A SLIGHT
WARMING TREND IN TEMPERATURES THROUGH THE WEEK.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
BROKEN MID LEVEL CLOUDS BETWEEN FL100-150 COVER THE AREA. BROKEN
TO OVERCAST LOW CLOUDS NEAR FL050 OVER EXTREME WESTERN AREA ARE
BEGINNING TO SPREAD EASTWARD. THESE LOW CLOUDS CONTAIN SHOWERS AND
PATCHES OF LIGHT RAIN IN ADVANCE OF THE COLD FRONT. SHOWERS ARE
FORECAST TO INCREASE IN INTENSITY AND COVERAGE INTO LATE MORNING.
THERE ARE SOME EARLY INDICATIONS THAT WE MAY SEE SOME CIGS FROM
KCVG TO KDAY DIP BELOW FL010 MID TO LATE MORNING FOR AN HOUR OR TWO.
WE WILL MONITOR THE SITUATION AND UPDATE THE FORECASTS IF OUR
CONFIDENCE INCREASES. THESE LOWER CIGS WOULD BE ASSOCIATED WITH
THE PERSISTENT RAIN AND HEAVY SHOWER ACTIVITY.
WITH THE EXCEPTION OF THE ABOVE MENTION IFR CONDS WE ARE EXPECTING
WIDESPREAD MVFR CONDS IN THE PCPN THIS MORNING WITH ONLY A BRIEF
LOWERING TO IFR IN VSBY IN SOME OF THE HEAVIEST SHOWERS. THIS PERIOD
OF PCPN SHOULD END AROUND NOON. AT THAT TIME THE MAIN THREAT WILL
BE THE POTENTIAL FOR WIDELY SCATTERED THUNDERSTORMS TO DEVELOPING
ALONG THE COLD FRONT AS IT MOVES EAST SOUTHEASTWARD ACROSS THE AREA
THIS AFTERNOON AND EVENING.
BEHIND THE FRONT LOW LEVEL DRY AIR WILL BEGIN TO PUSH IN CAUSING
THE LOW CLOUDS TO DISSIPATE. HOWEVER, MID LEVEL MOISTURE IS
EXPECTED TO BE SLOW TO RETREAT FROM THE AREA SO MID LEVEL CLOUDS
ARE CURRENTLY EXPECTED TO PERSIST THROUGH MOST OF THE NIGHTTIME
HOURS.
IN ADVANCE OF THE FRONT SURFACES WINDS WILL BE SOUTHWEST 5-12KT
BECOMING NORTHWEST AROUND 10KT BEHIND THE FRONT.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/NOVAK
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS MEDFORD OR
252 PM PDT SAT JUL 27 2013
.DISCUSSION...AN UPPER TROUGH IS APPROACHING THE FORECAST AREA
TODAY...AND IS IMPACTING OUR WEATHER IN SEVERAL WAYS.
FIRST...TEMPERATURES ARE ABOUT 5 TO 10 DEGREES COOLER THAN
YESTERDAY AT THIS TIME AS THE AIR MASS BECOMES DRIER AND COOLER.
SECOND...WINDS ARE INCREASING ACROSS THE FORECAST AREA THIS
AFTERNOON IN RESPONSE TO TIGHTENING ONSHORE PRESSURE
GRADIENTS...LIKELY CAUSING SEVERAL FIRES IN THE REGION TO BECOME
MORE ACTIVE. THIRD...GIVEN THE LIGHT TO MODERATE NORTH WINDS
ALOFT...SMOKE FROM THE FIRES IS SPREADING TO THE SOUTH INTO MOSTLY
JACKSON...JOSEPHINE...CURRY...AND SISKIYOU COUNTIES.
LINGERING INSTABILITY MAY PRODUCE SOME THUNDERSTORMS OVER NORTHERN
CALIFORNIA TODAY...BUT STABILITY AND A VERY DRY AIR MASS SHOULD
PREVENT THUNDERSTORMS FROM FORMING ELSEWHERE. THE LATEST HRRR MODEL
RUN CONFIRMS THIS IDEA...AND THIS MODEL HAS DONE FAIRLY WELL OVER
THE PAST COUPLE DAYS FOR AFTERNOON THUNDERSTORM ACTIVITY.
AS THE DAYS PROGRESS, BREEZY AFTERNOON CONDITIONS WILL
CONTINUE...WITH WINDS PEAKING ON THE WEST SIDE TODAY AND
SUNDAY...AND PEAKING ON THE EAST SIDE SUNDAY AND MONDAY. WINDS ALOFT
WILL LIKELY SWITCH TO A MORE WESTERLY DIRECTION BY MONDAY...PERHAPS
SHIFTING SMOKE FROM FIRES TOWARD THE EAST MORE THAN THE CURRENT
SITUATION. ADDITIONALLY...THE MARINE LAYER WILL GRADUALLY DEEPEN
ALONG THE COAST...PUSHING CLOUDS FARTHER AND FARTHER INLAND EACH
MORNING. THESE CLOUDS WILL LIKELY REACH ROSEBURG BY MONDAY MORNING
AND PERHAPS AS EARLY AS TOMORROW MORNING.
TEMPERATURES WILL LIKELY STABILIZE SUNDAY INTO EARLY NEXT
WEEK...WITH READINGS AROUND NORMAL FOR THIS TIME OF YEAR.
BY TUESDAY AND WEDNESDAY...MODELS ARE IN GOOD AGREEMENT ABOUT A
SIGNIFICANT CLOSED UPPER LOW DROPPING IN FROM THE
NORTHWEST...BRINGING ANOTHER ROUND OF COOLING. TEMPERATURES WILL
LIKELY DROP BELOW NORMAL BY MIDWEEK. MARINE CLOUDS SHOULD STICK
AROUND THE COAST AND CONTINUE TO REACH THE UMPQUA BASIN LATE AT
NIGHT AND EARLY IN THE MORNING...AND AT LEAST INFLUENCE THE FIRES IN
DOUGLAS AND JOSEPHINE COUNTY WITH SOME HIGHER HUMIDITIES. ITS
UNLIKELY THE TROUGH WILL BE STRONG ENOUGH TO MIX OUT THE MARINE
LAYER...BUT IT IS AN OUTSIDE CHANCE.
AHEAD OF THIS CLOSED LOW ON TUESDAY THROUGH THURSDAY...MODELS
SUGGEST SOME INSTABILITY EAST OF THE CASCADES. WE HAVE BUMPED UP
POPS SOME...BUT HAVE LEFT OUT ANY PRECIPITATION FOR THE TIME BEING.
INSTABILITY IS MARGINAL AND WOULD LIKE TO SEE A FEW MORE MODEL RUNS
BEFORE PLACING SHOWERS OR THUNDERSTORMS EAST OF THE CASCADES.
&&
.AVIATION...NORTHWEST WINDS ARE BECOMING GUSTY THIS AFTERNOON
ACROSS THE FORECAST AREA. THUNDERSTORMS MAY FORM LATER THIS
AFTERNOON OVER NORTHERN CALIFORNIA AND WILL DIMINISH TONIGHT.
SMOKE WILL CONTINUE TO DRIFT SOUTH FROM SOUTHERN DOUGLAS COUNTY
INTO CURRY...JOSEPHINE...JACKSON...AND SISKIYOU COUNTIES...AND MAY
SPREAD AS FAR EAST AS KLAMATH COUNTY THIS EVENING.
ALONG THE COAST...MARINE STRATUS WILL FILL BACK IN MOSTLY NORTH OF CAPE
BLANCO WITH IFR CONDITIONS LIKELY TONIGHT...SPREADING INTO THE
COASTAL VALLEY EARLY SUNDAY MORNING. ANY COASTAL STRATUS SHOULD
CLEAR BY LATE SUNDAY MORNING.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ031.
CA...NONE.
PACIFIC COASTAL WATERS...GALE WARNING UNTIL 8 PM PDT THIS EVENING FOR PZZ356.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT SUNDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT SUNDAY FOR
PZZ350-370.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT SUNDAY
FOR PZZ370.
GALE WARNING UNTIL 11 PM PDT SUNDAY FOR PZZ376.
HAZARDOUS SEAS WARNING UNTIL 11 AM PDT MONDAY FOR PZZ376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT SUNDAY
FOR PZZ350.
$$
NSK/NSK/NSK
AREA FORECAST DISCUSSION
NWS MEDFORD OR
934 PM PDT FRI JUL 26 2013
.DISCUSSION...EVENING UPDATE. THUNDERSTORMS CONTINUE TO DIMINISH
ACROSS THE REGION WITH THUNDERSTORMS REMAINING IN ROUGHLY A MEDICINE
LAKE TO PAISLEY LINE AND TO THE SE. CURRENT FORECAST HAS THIS AND
WILL NOT UPDATE THIS EVENING.
ANOTHER HOT DAY IS OCCURRING ACROSS THE AREA...THOUGH
TEMPERATURES HAVE COOLED A BIT...ABOUT 5 DEGREES COOLER THAN
YESTERDAY. INSTABILITY AND AMPLE UPPER MOISTURE IS HELPING TO
GENERATE THUNDERSTORMS EAST OF THE CASCADES AND OVER NORTHERN
CALIFORNIA. THE AREAS EXPECTED TO GET THE MOST THUNDERSTORM
ACTIVITY ARE MODOC AND LAKE COUNTIES...WITH THE HRRR SHORT-RANGE
GUIDANCE AND OBSERVED LIGHTNING STRIKES SUPPORTING THIS. A RED
FLAG WARNING AT RFW HAS BEEN ISSUED FOR LAKE...EASTERN MODOC...AND
EXTREME EASTERN KLAMATH COUNTIES. WEST OF THE CASCADES CONVECTIVE
INHIBITION...AS IS SHOWN IN FORECAST SOUNDINGS AND IN THE CURRENT
CLOUD DEVELOPMENT WHICH IS LIMITED IN VERTICAL DEVELOPMENT.
A COOLDOWN AND TRANSITION TOWARD NORMAL OR JUST BELOW NORMAL
TEMPERATURES WILL BE UNDERWAY TONIGHT INTO NEXT WEEK. TOMORROW THERE
IS ONE MORE CHANCE OF THUNDERSTORMS OVER NORTHERN CALIFORNIA WITH
LINGERING INSTABILITY THERE. ELSEWHERE...WESTERLIES AND STABLE
CONDITIONS WILL PREVENT THUNDERSTORM ACTIVITY. THE MARINE LAYER
WILL DEEPEN AND SEND CLOUDS FURTHER INLAND OVER THE NEXT COUPLE
MORNINGS...REACHING ROSEBURG BY SUNDAY MORNING. FOG WILL BEGIN TO
SUBSIDE AT THE COAST AS THE MARINE LAYER DEEPENS AND CLOUD BASES
RISE SOME...WITH DRIZZLE.
DRY AND COOL WEATHER WILL CONTINUE THROUGH EARLY NEXT WEEK...AND BY
WEDNESDAY MORNING DRIZZLE MAY AFFECT THE NORTH COAST AREA AROUND
NORTH BEND. THUNDERSTORMS ARE NOT EXPECTED AT THIS TIME AND HAVE
KEPT THEM OUT OF THE EXTENDED PORTION OF THE FORECAST...WITH
SOUTHWEST AND WEST FLOW ALOFT...SIGNALING A CONTINUING STABLE AIR
MASS.
&&
.AVIATION...MARINE STRATUS HAS CLEARED FROM THE COASTAL AREAS
THIS MORNING...BUT LOW CLOUDS WILL RETURN TO THE SAME AREAS OF
COOS AND WESTERN DOUGLAS COUNTY AROUND 03Z THIS
EVENING...PERSISTING INTO SATURDAY MORNING. INLAND...VFR IS
EXPECTED OVER THE NEXT 24 HOURS. THUNDERSTORMS WILL CONTINUE THIS
AFTERNOON AND EVENING FROM NORTHERN CALIFORNIA NORTHEASTWARD INTO
KLAMATH AND LAKE COUNTIES. GUSTY AND VARIABLE WINDS WILL ACCOMPANY
THUNDERSTORMS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR ORZ030.
RED FLAG WARNING UNTIL 8 PM PDT SATURDAY FOR ORZ031.
CA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR CAZ085.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM
PDT SATURDAY FOR
PZZ356.
GALE WARNING FROM 11 AM TO 8 PM PDT SATURDAY FOR PZZ356.
HAZARDOUS SEAS WARNING UNTIL 11 PM PDT SUNDAY FOR PZZ356.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 AM PDT SUNDAY FOR
PZZ350-370.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT SUNDAY
FOR PZZ350.
HAZARDOUS SEAS WARNING UNTIL 5 AM PDT SUNDAY FOR PZZ370.
GALE WARNING UNTIL 11 PM PDT SUNDAY FOR PZZ376.
HAZARDOUS SEAS WARNING UNTIL 11 AM PDT MONDAY FOR PZZ376.
$$
NSK/NSK/BPN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
222 AM EDT SAT JUL 27 2013
.SYNOPSIS...
PRECIPITATION CHANCES WILL REMAIN IN THE FORECAST THROUGH THE
WEEKEND AS A SERIES OF UPPER LEVEL DISTURBANCES AND A COLD FRONT
PASS THROUGH. CONDITIONS LOOK TO IMPROVE SLIGHTLY FOR THE START OF
NEXT WEEK AS SURFACE HIGH PRESSURE BUILDS WHILE REDUCING CHANCES FOR
PRECIPITATION.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 145 AM EDT SATURDAY...SHOWERS AND THUNDERSTORMS ARE INCREASING
OVER THE NC FOOTHILLS AND PORTIONS OF UPSTATE SC IN RESPONSE TO
INCREASING UPSLOPE FLOW AND PVA OVER THE REGION. POPS WERE INCREASED
ACCORDINGLY AND EXPECT THE COVERAGE OF PRECIP TO INCREASE THROUGH
THE OVERNIGHT HOURS. SO FAR...NONE OF STORMS HAVE REACHED SEVERE
LEVEL DUE TO LIMITED BUOYANCY. THE MAIN THREAT FROM THESE STORMS
WILL BE HEAVY RAINFALL AND LOCALIZED FLOODING.
AS OF 945 PM EDT FRIDAY...SHOWERS AND THUNDERSTORMS ARE GRADUALLY
INCREASING OVER NE GA...THE WRN UPSTATE AND THE CENTRAL AND SW NC
MTNS. THIS IS GENERALLY WHAT WAS EXPECTED...THOUGH IT/S A FEW HOURS
EARLIER THAN EXPECTED. I SUSPECT THAT THIS CONVECTION WILL CONTINUE
TO SLOWLY MOVE NORTHEAST THE REST OF THE NIGHT...AND IT/S POSSIBLE
THAT MORE WILL DEVELOP ALONG THE BLUE RIDGE AS THE LLVL FLOW
INCREASES LATE. THE STRENGTHENING WINDS WILL BE IN RESPONSE TO AN
APPROACHING SHORT WAVE WHICH SHOWS UP WELL ON THE RUC H5 ANALYSIS
AND THE WATER VAPOR IMAGERY PRETTY MUCH RIGHT OVER THE MISSISSIPPI
RIVER ATTM. LOCALLY HEAVY RAIN AND EVEN A SEVERE STORM ARE TWO STILL
LOOK LIKE A GOOD BET.
AS OF 600 PM EDT FRIDAY...UPPED POPS INTO THE LIKELY CATEGORY ACROSS
A BROAD SECTION OF THE CENTRAL PART OF THE FA LATER TONIGHT. MOST OF
THE CONVECTIVE ALLOWING MODELS DEVELOP SHOWERS AND THUNDERSTORMS
LATER TONIGHT AS THE LLVL FLOW INCREASES TO 20 TO 25 KTS AND A
RATHER POTENT SHORT WAVE APPROACHES FROM THE BEST. IT APPEARS THAT
RAIN CHANCES WILL BE HIGHEST ACROSS THE BLUE RIDGE AND OUT INTO THE
FOOTHILLS WHERE UPSLOPE WILL AID ASCENT. LOCALLY VERY HEAVY RAIN IS
POSSIBLE WITH THE STORMS...WHICH HAS BASICALLY BEEN THE STORY OF THE
SUMMER. WITH DRY MID-LEVEL AIR...A FEW AREAS OF LARGE HAIL DAMAGING
STRAIGHT LINE WINDS WILL ALSO BE POSSIBLE...ESPECIALLY EARLY ON IN
THE EVENT...SAY BETWEEN 8 PM AND MIDNIGHT.
PREVIOUS DISCUSSION...ISOLATED DEEP CONVECTION CONTINUES TO DEVELOP
ACROSS THE FOOTHILLS AND THE UPPER SAVANNAH RIVER VALLEY. A LACK OF
TRULY ROBUST INSTABILITY (DUE TO WARM MID-LEVEL TEMPS) IS LIMITING
THE VERTICAL DEVELOPMENT OF THE CONVECTION...AND THERE HAS BEEN NO
LIGHTNING ACTIVITY OBSERVED THUS FAR (IN FACT...CELLS HAVE NOT EVEN
COME CLOSE TO BEING ENOUGH TO PRODUCE LIGHTNING). NEVERTHELESS...CU
IS BEGINNING TO APPEAR SOMEWHAT AGITATED OVER THE HIGH TERRAIN...AND
AS THE ATM CONTINUES TO HEAT UP...COVERAGE AND INTENSITY OF
CONVECTION SHOULD GRADUALLY INCREASE. WE WILL CONTINUE TO ADVERTISE
A GRADUAL INCREASE IN POPS TO LOW/SOLID CHANCE ACROSS THE WESTERN
HALF OF THE AREA BY LATE AFTERNOON...WHILE HOLDING ON TO SLIGHT
COVERAGE AT BEST IN THE WEAKER INSTABILITY ACROSS OUR EASTERN
PIEDMONT ZONES.
THE SHORT TERM MODELS CONTINUE TO PICK UP ON A WEAK VORT MAX...
POSSIBLY CONVECTIVELY INDUCED AND A PRECURSOR TO THE PRIMARY SHORT
WAVE CURRENTLY APPROACHING THE MISS VALLEY...MOVING ACROSS THE CWA
THIS EVENING INTO THE EARLY PART OF THE OVERNIGHT. IN RESPONSE...
MOST MODELS...INCLUDING THE HIRES MODELS...HINT AT INCREASING
COVERAGE OF CONVECTION TONIGHT. OUR CURRENT EXPECTATION IS THAT THIS
WAVE WILL SWEEP THE MORE ROBUST CONVECTIVE ACTIVITY CURRENTLY
DEVELOPING OVER CENTRAL GEORGIA ACROSS THE WESTERN HALF OF THE CWA
THIS EVENING...SO WILL GENERALLY FEATURE 40-50 POPS ACROSS MUCH OF
THE AREA DURING THIS TIME. SHEAR IS WEAK AND INSTABILITY COULD
CERTAINLY BE BETTER...BUT AN ISOLATED PULSE SEVERE STORM WILL BE
POSSIBLE ALONG WITH THE THREAT OF HEAVY RAIN THREAT.
TOMORROW MAY BE AN INTERESTING DAY AS THE PRIMARY VORT MAX
APPROACHES FROM THE TENN VALLEY. DEEP LAYER FLOW WILL STRENGTHEN IN
ADVANCE OF THIS FEATURE SUCH THAT SHEAR IS QUITE RESPECTABLE FOR
MID-SUMMER (20-25 KTS 0-3 KM...30-35 KTS 0-6 KM). THE PRIMARY
CONCERN WILL BE WITH THE DEGREE OF INSTABILITY...AS THE
STRENGTHENING S/SE FLOW SHOULD ALSO RESULT IN PLENTY OF MORNING
STRATOCU. NEVERTHELESS...MODEL SOUNDINGS DEPICT QUITE A BIT OF
LINGERING DRY MID-LEVEL AIR...SO WE COULD SEE ENOUGH HEATING TO
REALIZE CLOSE TO 2000 J/KG CAPE VALUES. IF SO...WE MAY WELL SEE AN
ORGANIZED SEVERE WEATHER THREAT. CONSIDERING THE UNCERTAINTY ABOUT
THE DEGREE OF HEATING...THE CURRENT SPC /SEE TEXT/5 PERCENT AREA
APPEARS REASONABLE FOR DAY 2.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
AS OF 200 PM EDT FRI...NUMEROUS SHOWERS/THUNDERSTORMS SHOULD BE ON
GOING SAT EVENING OVER EASTERN SECTIONS...IN RESPONSE TO A VIGOROUS
VORT MAX MOVING THROUGH THE CAROLINAS. I EXPECT THAT THE MAIN BODY
OF SHOWERS/STORMS WILL MOVE EAST OF THE AREA BY MIDNIGHT.
HOWEVER...A WEAK COLD FRONT WILL SLIP SE TO THE LEE OF THE MOUNTAINS
BY DAYBREAK SUNDAY...SO WILL NEED TO HOLD ONTO SOME CHANCE POPS
OVERNIGHT FOR SOME UPSLOPE MOUNTAIN SHOWERS...AND PERHAPS SOME
SHOWERS AND THUNDERSTORMS INDUCED BY THE FRONT.
ON SUNDAY...THE FRONT WILL LINGER OVER THE REGION AS AN UPPER LOW
DIGS OVER THE GREAT LAKES. LOW LEVEL CONVERGENCE COMBINED WITH UPPER
DIFFLUENCE AND AFTERNOON CAPES PEAKING AROUND 1500J IN THE AFTERNOON
SHOULD BE ENOUGH FOR SCT TO NUMEROUS SHOWERS AND THUNDERSTORMS...
MOST NUMEROUS OVER EASTERN SECTIONS. SOME SHOWERS/STORMS COULD LINGER INTO
SUNDAY EVENING OVER THE EAST. HOWEVER...THE FRONT WILL FINALLY MOVE
EAST OF THE AREA OVERNIGHT WITH HIGH PRESSURE BUILDING IN FROM THE
WEST.
ON MONDAY...THE SURFACE HIGH IS FORECAST TO DOMINATE THE REGIONAL
WEATHER. THEREFORE...EXPECT A DRY DAY WITH MOSTLY CLEAR TO PARTLY
CLOUDY CONDITIONS. STAYED CLOSE TO CONSENSUS GUIDANCE FOR MOST GRID
FIELDS. MAX TEMPS WILL BE A COUPLE CATEGORIES BELOW AVERAGE ON
SUNDAY...WARMING TO ABOUT A CATEGORY BELOW AVERAGE MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM FRIDAY...THE EXTENDED PERIOD BEGINS LATE MONDAY WITH
HIGH PRESSURE BUILDING IN OVER THE EAST COAST BEHIND THE DEPARTING
FRONTAL SYSTEM...USHERING IN DRIER AIR OVER THE CWA FOR THE
BEGINNING OF NEXT WEEK. THE COMBINATION OF INVERSIONS AND WARMER AIR
ALOFT SHOULD KEEP MOST OF THE AREA CAPPED THROUGH MIDWEEK...ALLOWING
ONLY FOR SLIGHT CHANCE POPS MONDAY AND CHANCE POPS TUESDAY
AFTERNOON. THE AIRMASS BEGINS TO SATURATE AGAIN BY WEDNESDAY AS
ANOTHER TROUGH DIPS DOWN...AND THE MOIST AIR COMBINED WITH AN
APPROACHING SHORTWAVE WILL MAKE FOR GREATEST POPS WEDNESDAY
AFTERNOON/EVENING. IMPROVED DEEP LAYER MOISTURE AND GENERAL
TROUGHINESS OVER THE SOUTHEASTERN CONUS WILL KEEP THE PATTERN
UNSETTLED WITH MORE DIURNALLY DRIVEN CONVECTION THROUGH THE END OF
NEXT WEEK.
CLOUD COVER AT THE BEGINNING OF THE PERIOD WILL KEEP HIGH TEMPS
BELOW AVERAGE...AND HIGHS WILL REMAIN COOLER THAN NORMAL THROUGH THE
END OF NEXT WEEK DUE TO LOWER THICKNESS ADVECTION. LOWS WILL BE NEAR
AVERAGE FOR THE ENTIRE MEDIUM RANGE.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...A LINE OF CONVECTION EXTENDING FROM THE NORTHERN NC
FOOTHILLS TO I-26 CORRIDOR WAS RATHER SLOWLY MOVING EAST TOWARD THE
AIRFIELD OVERNIGHT HOURS. THIS LINE MAY AFFECT THE TERMINAL BETWEEN
7Z AND 9Z SAT AND TEMPO THUNDER WAS MENTIONED ACCORDINGLY. CURRENT
VFR CONDITIONS WILL DEGRADE TO MVFR ONCE THE LINE MOVES THE FIELD
AND MVFR CLOUD DECK WITH INTERMITTENT SHOWERS WILL CONTINUE THROUGH
THE MORNING HOURS. WITH DIURNAL HEATING AND THE PASSAGE OF UPPER
SHORT WAVE ENERGY ON SAT...SHOWERS AND THUNDERSTORMS WILL
RE-DEVELOPER DURING THE PRIME HEATING HOURS. LIGHT SOUTHERLY WINDS
WILL PREVAIL THRU THE PERIOD THOUGH STRONGER WIND GUSTS ARE POSSIBLE
IN THUNDERSTORMS.
ELSEWHERE...A LINE OF SHRA/TSTMS WAS MOVING EAST ACROSS THE NC
FOOTHILLS AND UPSTATE SC OVERNIGHT HOURS. AREAS BEHIND THIS LINE
WILL REMAIN RELATIVELY QUIET THOUGH INTERMITTENT SHOWERS WILL BE
SEEN INTO THE MORNING HOURS. ONCE AGAIN...KAVL MAY SEE PATCHY FOG
WITH BRIEF IFR VISBY/CEILING TOWARD THE SUNRISE. AN UPPER SHORT WAVE
ENERGY WILL SWING ACROSS THE REGION DURING THE DAY ON SAT. THIS WILL
COMBINE WITH DIURNAL INSTABILITY TO TRIGGER CONVECTION DURING THE
AFTERNOON HOURS. LIGHT SOUTHERLY WINDS WILL PREVAIL FOR MOST
LOCATIONS THOUGH STRONGER WIND GUSTS CAN NOT BE RULED OUT IN
THUNDERSTORMS. KAVL WILL SEE WINDS VEERING TO THE NORTH BY THE
EVENING HOURS.
OUTLOOK...CONVECTION WILL DEVELOP AGAIN SUNDAY...BUT COVERAGE SHOULD
BE DIMINISHING. BRIEF DRYING IS POSSIBLE ON MON AND TUE WITH HIGH
PRES FOLLOWING FROPA.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT MED 60% MED 76% HIGH 87% HIGH 93%
KGSP MED 71% MED 76% HIGH 82% MED 64%
KAVL HIGH 94% HIGH 83% HIGH 81% MED 60%
KHKY MED 63% HIGH 88% MED 68% MED 69%
KGMU MED 72% HIGH 80% HIGH 81% MED 64%
KAND MED 71% HIGH 83% HIGH 91% MED 61%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...JOH/MCAVOY
SHORT TERM...LG
LONG TERM...VISIN
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
157 AM EDT SAT JUL 27 2013
.SYNOPSIS...
PRECIPITATION CHANCES WILL REMAIN IN THE FORECAST THROUGH THE
WEEKEND AS A SERIES OF UPPER LEVEL DISTURBANCES AND A COLD FRONT
PASS THROUGH. CONDITIONS LOOK TO IMPROVE SLIGHTLY FOR THE START OF
NEXT WEEK AS SURFACE HIGH PRESSURE BUILDS WHILE REDUCING CHANCES FOR
PRECIPITATION.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 145 AM EDT SATURDAY...SHOWERS AND THUNDERSTORMS ARE INCREASING
OVER THE NC FOOTHILLS AND PORTIONS OF UPSTATE SC IN RESPONSE TO
INCREASING UPSLOPE FLOW AND PVA OVER THE REGION. POPS WERE INCREASED
ACCORDINGLY AND EXPECT THE COVERAGE OF PRECIP TO INCREASE THROUGH
THE OVERNIGHT HOURS. SO FAR...NONE OF STORMS HAVE REACHED SEVERE
LEVEL DUE TO LIMITED BUOYANCY. THE MAIN THREAT FROM THESE STORMS
WILL BE HEAVY RAINFALL AND LOCALIZED FLOODING.
AS OF 945 PM EDT FRIDAY...SHOWERS AND THUNDERSTORMS ARE GRADUALLY
INCREASING OVER NE GA...THE WRN UPSTATE AND THE CENTRAL AND SW NC
MTNS. THIS IS GENERALLY WHAT WAS EXPECTED...THOUGH IT/S A FEW HOURS
EARLIER THAN EXPECTED. I SUSPECT THAT THIS CONVECTION WILL CONTINUE
TO SLOWLY MOVE NORTHEAST THE REST OF THE NIGHT...AND IT/S POSSIBLE
THAT MORE WILL DEVELOP ALONG THE BLUE RIDGE AS THE LLVL FLOW
INCREASES LATE. THE STRENGTHENING WINDS WILL BE IN RESPONSE TO AN
APPROACHING SHORT WAVE WHICH SHOWS UP WELL ON THE RUC H5 ANALYSIS
AND THE WATER VAPOR IMAGERY PRETTY MUCH RIGHT OVER THE MISSISSIPPI
RIVER ATTM. LOCALLY HEAVY RAIN AND EVEN A SEVERE STORM ARE TWO STILL
LOOK LIKE A GOOD BET.
AS OF 600 PM EDT FRIDAY...UPPED POPS INTO THE LIKELY CATEGORY ACROSS
A BROAD SECTION OF THE CENTRAL PART OF THE FA LATER TONIGHT. MOST OF
THE CONVECTIVE ALLOWING MODELS DEVELOP SHOWERS AND THUNDERSTORMS
LATER TONIGHT AS THE LLVL FLOW INCREASES TO 20 TO 25 KTS AND A
RATHER POTENT SHORT WAVE APPROACHES FROM THE BEST. IT APPEARS THAT
RAIN CHANCES WILL BE HIGHEST ACROSS THE BLUE RIDGE AND OUT INTO THE
FOOTHILLS WHERE UPSLOPE WILL AID ASCENT. LOCALLY VERY HEAVY RAIN IS
POSSIBLE WITH THE STORMS...WHICH HAS BASICALLY BEEN THE STORY OF THE
SUMMER. WITH DRY MID-LEVEL AIR...A FEW AREAS OF LARGE HAIL DAMAGING
STRAIGHT LINE WINDS WILL ALSO BE POSSIBLE...ESPECIALLY EARLY ON IN
THE EVENT...SAY BETWEEN 8 PM AND MIDNIGHT.
PREVIOUS DISCUSSION...ISOLATED DEEP CONVECTION CONTINUES TO DEVELOP
ACROSS THE FOOTHILLS AND THE UPPER SAVANNAH RIVER VALLEY. A LACK OF
TRULY ROBUST INSTABILITY (DUE TO WARM MID-LEVEL TEMPS) IS LIMITING
THE VERTICAL DEVELOPMENT OF THE CONVECTION...AND THERE HAS BEEN NO
LIGHTNING ACTIVITY OBSERVED THUS FAR (IN FACT...CELLS HAVE NOT EVEN
COME CLOSE TO BEING ENOUGH TO PRODUCE LIGHTNING). NEVERTHELESS...CU
IS BEGINNING TO APPEAR SOMEWHAT AGITATED OVER THE HIGH TERRAIN...AND
AS THE ATM CONTINUES TO HEAT UP...COVERAGE AND INTENSITY OF
CONVECTION SHOULD GRADUALLY INCREASE. WE WILL CONTINUE TO ADVERTISE
A GRADUAL INCREASE IN POPS TO LOW/SOLID CHANCE ACROSS THE WESTERN
HALF OF THE AREA BY LATE AFTERNOON...WHILE HOLDING ON TO SLIGHT
COVERAGE AT BEST IN THE WEAKER INSTABILITY ACROSS OUR EASTERN
PIEDMONT ZONES.
THE SHORT TERM MODELS CONTINUE TO PICK UP ON A WEAK VORT MAX...
POSSIBLY CONVECTIVELY INDUCED AND A PRECURSOR TO THE PRIMARY SHORT
WAVE CURRENTLY APPROACHING THE MISS VALLEY...MOVING ACROSS THE CWA
THIS EVENING INTO THE EARLY PART OF THE OVERNIGHT. IN RESPONSE...
MOST MODELS...INCLUDING THE HIRES MODELS...HINT AT INCREASING
COVERAGE OF CONVECTION TONIGHT. OUR CURRENT EXPECTATION IS THAT THIS
WAVE WILL SWEEP THE MORE ROBUST CONVECTIVE ACTIVITY CURRENTLY
DEVELOPING OVER CENTRAL GEORGIA ACROSS THE WESTERN HALF OF THE CWA
THIS EVENING...SO WILL GENERALLY FEATURE 40-50 POPS ACROSS MUCH OF
THE AREA DURING THIS TIME. SHEAR IS WEAK AND INSTABILITY COULD
CERTAINLY BE BETTER...BUT AN ISOLATED PULSE SEVERE STORM WILL BE
POSSIBLE ALONG WITH THE THREAT OF HEAVY RAIN THREAT.
TOMORROW MAY BE AN INTERESTING DAY AS THE PRIMARY VORT MAX
APPROACHES FROM THE TENN VALLEY. DEEP LAYER FLOW WILL STRENGTHEN IN
ADVANCE OF THIS FEATURE SUCH THAT SHEAR IS QUITE RESPECTABLE FOR
MID-SUMMER (20-25 KTS 0-3 KM...30-35 KTS 0-6 KM). THE PRIMARY
CONCERN WILL BE WITH THE DEGREE OF INSTABILITY...AS THE
STRENGTHENING S/SE FLOW SHOULD ALSO RESULT IN PLENTY OF MORNING
STRATOCU. NEVERTHELESS...MODEL SOUNDINGS DEPICT QUITE A BIT OF
LINGERING DRY MID-LEVEL AIR...SO WE COULD SEE ENOUGH HEATING TO
REALIZE CLOSE TO 2000 J/KG CAPE VALUES. IF SO...WE MAY WELL SEE AN
ORGANIZED SEVERE WEATHER THREAT. CONSIDERING THE UNCERTAINTY ABOUT
THE DEGREE OF HEATING...THE CURRENT SPC /SEE TEXT/5 PERCENT AREA
APPEARS REASONABLE FOR DAY 2.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
AS OF 200 PM EDT FRI...NUMEROUS SHOWERS/THUNDERSTORMS SHOULD BE ON
GOING SAT EVENING OVER EASTERN SECTIONS...IN RESPONSE TO A VIGOROUS
VORT MAX MOVING THROUGH THE CAROLINAS. I EXPECT THAT THE MAIN BODY
OF SHOWERS/STORMS WILL MOVE EAST OF THE AREA BY MIDNIGHT.
HOWEVER...A WEAK COLD FRONT WILL SLIP SE TO THE LEE OF THE MOUNTAINS
BY DAYBREAK SUNDAY...SO WILL NEED TO HOLD ONTO SOME CHANCE POPS
OVERNIGHT FOR SOME UPSLOPE MOUNTAIN SHOWERS...AND PERHAPS SOME
SHOWERS AND THUNDERSTORMS INDUCED BY THE FRONT.
ON SUNDAY...THE FRONT WILL LINGER OVER THE REGION AS AN UPPER LOW
DIGS OVER THE GREAT LAKES. LOW LEVEL CONVERGENCE COMBINED WITH UPPER
DIFFLUENCE AND AFTERNOON CAPES PEAKING AROUND 1500J IN THE AFTERNOON
SHOULD BE ENOUGH FOR SCT TO NUMEROUS SHOWERS AND THUNDERSTORMS...
MOST NUMEROUS OVER EASTERN SECTIONS. SOME SHOWERS/STORMS COULD LINGER INTO
SUNDAY EVENING OVER THE EAST. HOWEVER...THE FRONT WILL FINALLY MOVE
EAST OF THE AREA OVERNIGHT WITH HIGH PRESSURE BUILDING IN FROM THE
WEST.
ON MONDAY...THE SURFACE HIGH IS FORECAST TO DOMINATE THE REGIONAL
WEATHER. THEREFORE...EXPECT A DRY DAY WITH MOSTLY CLEAR TO PARTLY
CLOUDY CONDITIONS. STAYED CLOSE TO CONSENSUS GUIDANCE FOR MOST GRID
FIELDS. MAX TEMPS WILL BE A COUPLE CATEGORIES BELOW AVERAGE ON
SUNDAY...WARMING TO ABOUT A CATEGORY BELOW AVERAGE MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM FRIDAY...THE EXTENDED PERIOD BEGINS LATE MONDAY WITH
HIGH PRESSURE BUILDING IN OVER THE EAST COAST BEHIND THE DEPARTING
FRONTAL SYSTEM...USHERING IN DRIER AIR OVER THE CWA FOR THE
BEGINNING OF NEXT WEEK. THE COMBINATION OF INVERSIONS AND WARMER AIR
ALOFT SHOULD KEEP MOST OF THE AREA CAPPED THROUGH MIDWEEK...ALLOWING
ONLY FOR SLIGHT CHANCE POPS MONDAY AND CHANCE POPS TUESDAY
AFTERNOON. THE AIRMASS BEGINS TO SATURATE AGAIN BY WEDNESDAY AS
ANOTHER TROUGH DIPS DOWN...AND THE MOIST AIR COMBINED WITH AN
APPROACHING SHORTWAVE WILL MAKE FOR GREATEST POPS WEDNESDAY
AFTERNOON/EVENING. IMPROVED DEEP LAYER MOISTURE AND GENERAL
TROUGHINESS OVER THE SOUTHEASTERN CONUS WILL KEEP THE PATTERN
UNSETTLED WITH MORE DIURNALLY DRIVEN CONVECTION THROUGH THE END OF
NEXT WEEK.
CLOUD COVER AT THE BEGINNING OF THE PERIOD WILL KEEP HIGH TEMPS
BELOW AVERAGE...AND HIGHS WILL REMAIN COOLER THAN NORMAL THROUGH THE
END OF NEXT WEEK DUE TO LOWER THICKNESS ADVECTION. LOWS WILL BE NEAR
AVERAGE FOR THE ENTIRE MEDIUM RANGE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...CU HAVE DRIED UP WITH THE LOSS OF HEATING AND THE AIRFIELD
SHOULD EXPERIENCE SEVERAL HOURS OF FAIR WEATHER. LATER TONIGHT
CONDITIONS WILL BE FAVORABLE FOR NOCTURNAL CONVECTION AND I HAVE A
TEMPO GROUP FOR TSTMS FROM 06-09 UTC. STILL EXPECT STRENGTHENING
SOUTHERLY FLOW ACTING UPON AN INCREASINGLY MOIST LOW LEVEL AIR MASS
TO RESULT IN THE DEVELOPMENT OF WIDESPREAD STRATUS ACROSS THE AREA
LATE TONIGHT. CIGS MAY BE LOWER TONIGHT WITH SOME PCPN IN THE AREA
AND I TAKE THEM DOWN TO BKN010 AT 0900 UTC. ONLY SLOW IMPROVEMENT IS
EXPECTED THROUGH THE MORNING HOURS WITH THE MOIST SE FLOW AND
POSSIBLE ONGOING SHOWER OR TSTM ACTIVITY. MORE ACTIVITY IS LIKELY IN
THE AFTERNOON AS A STRONGER UPPER LOW MOVES THROUGH. EXPECTING S TO
SE WINDS THROUGH THE PERIOD.
ELSEWHERE...A BROKEN LINE OF SHRA/TSTMS IS SLOWLY ADVANCING ACROSS
THE GA. CONDITIONS BECOME FAVORABLE FOR CONVECTION LATER
TONIGHT...THOUGH I/M NOT SURE IF THIS LINE WILL MAKE IT OR IF WE
WILL HAVE TO WAIT FOR MORE STORMS. AS A COMPROMISE...I HAVE TEMPO
THUNDER PROBS FROM 03-07. STRATUS IS A GOOD BET TONIGHT WITH MOIST
SOUTHEAST FLOW AND A LLVL WIND FIELD INCREASING TO AROUND 20 KTS.
WENT RIGHT ON THE CUSP OF IFR/MVFR. A LOT WILL DEPEND ON HOW MUCH
RAIN FALLS...BUT AS A RULE THAT MUCH LLVL WIND SHOULD KEEP US FROM
SEEING REALLY LOW CIGS. I DID GO LOWER AT KAVL. MORE SHRA/TSTMS ARE
EXPECTED TMRW. WINDS WILL BE S TO SE THROUGH THE PERIOD.
OUTLOOK...CONVECTION WILL DEVELOP AGAIN SUNDAY...BUT COVERAGE SHOULD
BE DIMINISHING. BRIEF DRYING IS POSSIBLE ON MON AND TUE WITH HIGH
PRES FOLLOWING FROPA.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT MED 60% MED 76% HIGH 87% HIGH 93%
KGSP MED 71% MED 76% HIGH 82% MED 64%
KAVL HIGH 94% HIGH 83% HIGH 81% MED 60%
KHKY MED 63% HIGH 88% MED 68% MED 69%
KGMU MED 72% HIGH 80% HIGH 81% MED 64%
KAND MED 71% HIGH 83% HIGH 91% MED 61%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...VISIN
NEAR TERM...JOH/MCAVOY
SHORT TERM...LG
LONG TERM...VISIN
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
111 PM CDT SAT JUL 27 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
WEAK COLD FRONT EXPECTED TO MOVE SLOWLY ACROSS THE MID-STATE THIS
AFTERNOON/TONIGHT. THIS WILL PRODUCE ISO-SCT STORMS BUT LARGELY
EAST OF BNA THRU 02Z. CEILINGS/VSBYS WILL STAY IN VFR RANGE WELL
INTO TONIGHT BARRING A DIRECT HIT AND THAT IS MAINLY CONCERNING
CSV. CLEARING SKIES OVERNIGHT WILL ALLOW FOG TO DEVELOP BEHIND
BOUNDARY. CONDITIONS MOST LIKELY MVFR LATE NIGHT HOURS CKV/BNA BUT
CSV CEILING/VSBYS EXPECTED TO DROP INTO IFR RANGE. ALL SITES
VFR BY 15Z MON.
&&
.PREV DISCUSSION... /ISSUED 514 AM CDT SAT JUL 27 2013/
UPDATE...
12Z TAF DISCUSSION.
AVIATION...
SCATTERED LIGHT RAIN SHOWERS CONTINUE TO SPREAD ACROSS CKV/BNA
THIS MORNING AND WILL BE NEAR CSV OVER THE NEXT FEW
HOURS...WARRANTING VCSH MENTION AT ALL AIRPORTS. SHORT TERM
GUIDANCE INDICATES A BREAK IN PRECIP BEFORE MORE SCATTERED SHOWERS
DEVELOP THIS AFTERNOON/EVENING AS COLD FRONT APPROACHES. VFR CIGS
ANTICIPATED THROUGH TAF PERIOD WITH LIGHT WEST WINDS BECOMING
NORTHWEST AFTER FROPA.
SHAMBURGER
PREV DISCUSSION... /ISSUED 342 AM CDT SAT JUL 27 2013/
DISCUSSION...
SHOWERS HAVE BEEN MOVING INTO THE WEST HALF OF MIDDLE TN EARLY
THIS MORNING AS A WEAK H5 TROF MOVES INTO THE REGION. TROF SHOULD
MOVE EAST OF THE REGION WITHIN THE NEXT FEW HOURS AND HRRR SHOWS
THESE SHOWERS ENDING LATER THIS MORNING.
VERY UNUSUAL FORECAST FOR MID SUMMER. H5 CLOSED LOW WILL MOVE
SLOWLY EAST THRU THE GREAT LAKES THIS WEEKEND. ASSOCIATED SFC LOW
WILL HELP BRING A COLD FRONT INTO NW MIDDLE TN LATE TODAY...AND TO
THE REST OF THE AREA BY MIDNIGHT. SCATTERED SHOWERS AND MAYBE A
FEW STORMS WILL REDEVELOP THIS AFTERNOON AND EARLY EVENING AHEAD
OF THE FRONT. RAINFALL AMOUNTS WILL BE LIGHT WITH LESS THAN 1/4
INCH IN MOST AREAS.
COOLER AND DRY WEATHER ON TAP FOR SUN/MON AS SFC RIDGE SETTLES
INTO MID TN. MONDAY MORNING MIN TEMPS COULD APPROACH RECORDS.
GFS GUIDANCE IS AN OUTLIER BY FORECASTING 2 DEGREES COLDER THAN
THE RECORD AT BNA...AND A WHOPPING 5 DEGREES COLDER THAN THE
RECORD AT CSV. SO...LEANED MORE TOWARD THE WARMER AND SEEMINGLY
MORE REASONABLE NAM/ECMWF GUIDANCE.
H5 HEIGHTS REBOUND BY TUESDAY AS GREAT LAKES LOW MOVES FURTHER
AWAY AND RIDGE REBUILDS ACROSS THE SOUTHERN U.S. HOWEVER...GFS AND
ECMWF SHOW WEAK NW FLOW ALOFT WITH A TROF APPROACHING THE MID
STATE TUE/WED...FOLLOWED BY ANOTHER BUT WEAKER COLD FRONT LATE
WEDNESDAY. WITH MEAN RH AND LIFT INCREASING...WILL GO WITH CHANCE
TYPE POPS TUESDAY THRU WEDNESDAY EVENING. GFS AND ECMWF BOTH SHOW
SIGNIFICANT QPF BULLS EYES BUT MAINLY IN SOUTHERN KY.
AFTER THE TROF MOVES AWAY...SOME DRYING IS EXPECTED THURSDAY AND
FRIDAY WITH TEMPS UP A FEW DEGREES AS THICKNESS/HEIGHTS EDGE
UPWARD. RAIN CHANCES MAY INCREASE AGAIN NEXT WEEKEND AS BOTH
MODELS SHOW YET ANOTHER WEAK FRONT MOVING SLOWLY INTO MIDDLE TN
FROM THE NORTH.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
514 AM CDT SAT JUL 27 2013
.UPDATE...
12Z TAF DISCUSSION.
&&
.AVIATION...
SCATTERED LIGHT RAIN SHOWERS CONTINUE TO SPREAD ACROSS CKV/BNA
THIS MORNING AND WILL BE NEAR CSV OVER THE NEXT FEW
HOURS...WARRANTING VCSH MENTION AT ALL AIRPORTS. SHORT TERM
GUIDANCE INDICATES A BREAK IN PRECIP BEFORE MORE SCATTERED SHOWERS
DEVELOP THIS AFTERNOON/EVENING AS COLD FRONT APPROACHES. VFR CIGS
ANTICIPATED THROUGH TAF PERIOD WITH LIGHT WEST WINDS BECOMING
NORTHWEST AFTER FROPA.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 342 AM CDT SAT JUL 27 2013/
DISCUSSION...
SHOWERS HAVE BEEN MOVING INTO THE WEST HALF OF MIDDLE TN EARLY
THIS MORNING AS A WEAK H5 TROF MOVES INTO THE REGION. TROF SHOULD
MOVE EAST OF THE REGION WITHIN THE NEXT FEW HOURS AND HRRR SHOWS
THESE SHOWERS ENDING LATER THIS MORNING.
VERY UNUSUAL FORECAST FOR MID SUMMER. H5 CLOSED LOW WILL MOVE
SLOWLY EAST THRU THE GREAT LAKES THIS WEEKEND. ASSOCIATED SFC LOW
WILL HELP BRING A COLD FRONT INTO NW MIDDLE TN LATE TODAY...AND TO
THE REST OF THE AREA BY MIDNIGHT. SCATTERED SHOWERS AND MAYBE A
FEW STORMS WILL REDEVELOP THIS AFTERNOON AND EARLY EVENING AHEAD
OF THE FRONT. RAINFALL AMOUNTS WILL BE LIGHT WITH LESS THAN 1/4
INCH IN MOST AREAS.
COOLER AND DRY WEATHER ON TAP FOR SUN/MON AS SFC RIDGE SETTLES
INTO MID TN. MONDAY MORNING MIN TEMPS COULD APPROACH RECORDS.
GFS GUIDANCE IS AN OUTLIER BY FORECASTING 2 DEGREES COLDER THAN
THE RECORD AT BNA...AND A WHOPPING 5 DEGREES COLDER THAN THE
RECORD AT CSV. SO...LEANED MORE TOWARD THE WARMER AND SEEMINGLY
MORE REASONABLE NAM/ECMWF GUIDANCE.
H5 HEIGHTS REBOUND BY TUESDAY AS GREAT LAKES LOW MOVES FURTHER
AWAY AND RIDGE REBUILDS ACROSS THE SOUTHERN U.S. HOWEVER...GFS AND
ECMWF SHOW WEAK NW FLOW ALOFT WITH A TROF APPROACHING THE MID
STATE TUE/WED...FOLLOWED BY ANOTHER BUT WEAKER COLD FRONT LATE
WEDNESDAY. WITH MEAN RH AND LIFT INCREASING...WILL GO WITH CHANCE
TYPE POPS TUESDAY THRU WEDNESDAY EVENING. GFS AND ECMWF BOTH SHOW
SIGNIFICANT QPF BULLS EYES BUT MAINLY IN SOUTHERN KY.
AFTER THE TROF MOVES AWAY...SOME DRYING IS EXPECTED THURSDAY AND
FRIDAY WITH TEMPS UP A FEW DEGREES AS THICKNESS/HEIGHTS EDGE
UPWARD. RAIN CHANCES MAY INCREASE AGAIN NEXT WEEKEND AS BOTH
MODELS SHOW YET ANOTHER WEAK FRONT MOVING SLOWLY INTO MIDDLE TN
FROM THE NORTH.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
342 AM CDT SAT JUL 27 2013
.DISCUSSION...
SHOWERS HAVE BEEN MOVING INTO THE WEST HALF OF MIDDLE TN EARLY
THIS MORNING AS A WEAK H5 TROF MOVES INTO THE REGION. TROF SHOULD
MOVE EAST OF THE REGION WITHIN THE NEXT FEW HOURS AND HRRR SHOWS
THESE SHOWERS ENDING LATER THIS MORNING.
VERY UNUSUAL FORECAST FOR MID SUMMER. H5 CLOSED LOW WILL MOVE
SLOWLY EAST THRU THE GREAT LAKES THIS WEEKEND. ASSOCIATED SFC LOW
WILL HELP BRING A COLD FRONT INTO NW MIDDLE TN LATE TODAY...AND TO
THE REST OF THE AREA BY MIDNIGHT. SCATTERED SHOWERS AND MAYBE A
FEW STORMS WILL REDEVELOP THIS AFTERNOON AND EARLY EVENING AHEAD
OF THE FRONT. RAINFALL AMOUNTS WILL BE LIGHT WITH LESS THAN 1/4
INCH IN MOST AREAS.
COOLER AND DRY WEATHER ON TAP FOR SUN/MON AS SFC RIDGE SETTLES
INTO MID TN. MONDAY MORNING MIN TEMPS COULD APPROACH RECORDS.
GFS GUIDANCE IS AN OUTLIER BY FORECASTING 2 DEGREES COLDER THAN
THE RECORD AT BNA...AND A WHOPPING 5 DEGREES COLDER THAN THE
RECORD AT CSV. SO...LEANED MORE TOWARD THE WARMER AND SEEMINGLY
MORE REASONABLE NAM/ECMWF GUIDANCE.
H5 HEIGHTS REBOUND BY TUESDAY AS GREAT LAKES LOW MOVES FURTHER
AWAY AND RIDGE REBUILDS ACROSS THE SOUTHERN U.S. HOWEVER...GFS AND
ECMWF SHOW WEAK NW FLOW ALOFT WITH A TROF APPROACHING THE MID
STATE TUE/WED...FOLLOWED BY ANOTHER BUT WEAKER COLD FRONT LATE
WEDNESDAY. WITH MEAN RH AND LIFT INCREASING...WILL GO WITH CHANCE
TYPE POPS TUESDAY THRU WEDNESDAY EVENING. GFS AND ECMWF BOTH SHOW
SIGNIFICANT QPF BULLS EYES BUT MAINLY IN SOUTHERN KY.
AFTER THE TROF MOVES AWAY...SOME DRYING IS EXPECTED THURSDAY AND
FRIDAY WITH TEMPS UP A FEW DEGREES AS THICKNESS/HEIGHTS EDGE
UPWARD. RAIN CHANCES MAY INCREASE AGAIN NEXT WEEKEND AS BOTH
MODELS SHOW YET ANOTHER WEAK FRONT MOVING SLOWLY INTO MIDDLE TN
FROM THE NORTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 85 61 81 60 / 40 10 0 0
CLARKSVILLE 83 56 80 58 / 30 10 0 0
CROSSVILLE 80 58 76 57 / 50 20 05 05
COLUMBIA 85 61 83 61 / 40 10 0 0
LAWRENCEBURG 84 61 83 62 / 40 10 0 0
WAVERLY 84 58 81 60 / 30 10 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
49
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1052 PM CDT SUN JUL 28 2013
.UPDATE...
MINOR CHANGES MADE TO THE FORECAST FOR THE REST OF THE NIGHT.
ISOLATED CONVECTION CONTINUES ACROSS PORTIONS OF THE CONCHO VALLEY
AND NORTH EDWARDS PLATEAU LATE THIS EVENING. WILL KEEP SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORM`S GOING OVERNIGHT FOR ROUGHLY
THE WESTERN HALF OF THE CWA AS A WEAK MID LEVEL DISTURBANCE
AFFECTS THE AREA. LATEST RUC SEEMS TOO AGGRESSIVE WITH QPF
OVERNIGHT WHILE THE HRRR SEEMS MORE REASONABLE. ONLY MINOR CHANGES
WERE MADE TO TEMPS AND DEWPOINTS TO ACCOUNT FOR TRENDS. UPDATED
PRODUCTS HAVE BEEN SENT.
&&
.PREV DISCUSSION... /ISSUED 621 PM CDT SUN JUL 28 2013/
UPDATE...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
AREA RADARS SHOW A FEW SHOWERS ACROSS THE NORTHWEST HILL COUNTRY
AND NORTHERN EDWARDS PLATEAU...BUT NOTHING THAT SEEMS TO BE
IMMINENT FOR THE TERMINAL LOCATIONS AT KJCT/JUNCTION...KBBD/BRADY...AND
KSOA/SONORA. COVERAGE IS ISOLATED AT BEST...BUT SHOULD CONTINUE
FOR AT LEAST THE NEXT FEW HOURS. HAVE INCLUDED A VCSH FOR THE
THOSE SITES AND WILL CONTINUE TO MONITOR. IF THOSE AREAS DO SEE A
SHOWER...THEN GUSTY WINDS AND BRIEF MVFR CIGS WILL BE POSSIBLE.
OTHERWISE...VFR CONDITIONS SHOULD PREVAIL. MODELS SUGGEST SOME
THREAT OF MVFR CIGS AS LOW CLOUDS DEVELOP ACROSS THE SOUTHERN AND
EASTERN AREA BY SUNRISE...AND WILL CONTINUE THE MENTION IN THE
FORECAST FOR NOW.
PREV DISCUSSION... /ISSUED 403 PM CDT SUN JUL 28 2013/
SHORT TERM...
/TONIGHT/
.SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MOST COUNTIES...
UPPER-LEVEL CIRCULATION...BASED ON THE LATEST WATER VAPOR
LOOP...DOES NOT LOOK AS PROMISING FOR POSSIBLE SHOWERS AND
THUNDERSTORMS TONIGHT. THE NAM AND GFS 500 MB WIND FIELDS INDICATE
A MINOR SHORT-WAVE TROUGH IN THE FLOW OVER SOUTHEASTERN NEW MEXICO
AND WEST TEXAS. THE NAM DEVELOPS THIS TROUGH MORE THAN THE GFS.
UNFORTUNATELY...ANALYSIS OF THE WATER VAPOR LOOP DOES NOT REVEAL
ANY INDICATION OF THIS TROUGH. THE OVERALL FLOW IN THIS AREA IS
NORTHWEST TO SOUTHEAST. THE NAM REALLY DEVELOPS QPF OVER MUCH OF
WEST CENTRAL TEXAS TONIGHT...AND THE MET MOS PRODUCTS PRESENT 60
POPS FOR BOTH ABILENE AND SAN ANGELO TONIGHT. THE MEX HAS ONLY 10
POPS. SO...WITH LOW CONFIDENCE...I DECIDED TO CONTINUE ONLY 20
POPS FOR TONIGHT. BUT...I EXPANDED THE 20 POPS AREA OVER MORE OF
WEST CENTRAL TEXAS TO ALL EXCEPT MAINLY THE NORTHWEST HILL
COUNTRY.
/TOMORROW/
.SLIGHT CHANCE POPS CONTINUES MOST LOCATIONS...
THE NAM CONTINUES AN UPPER-LEVEL TROUGH OVER WEST CENTRAL TEXAS
INTO TOMORROW. AGAIN...MY CONFIDENCE IS NOT HIGH. AT LEAST...IT IS
NOT HIGH ENOUGH TO GIVE ABILENE 50 POPS FOR TOMORROW AS THE MET
MOS PRODUCT INDICATES. SO...I WILL CONTINUE WITH ONLY SLIGHT
CHANCE POPS OVER AN ALMOST IDENTICAL AREA TO TONIGHT.
OTHERWISE...AFTERNOON HIGHS TOMORROW IN THE RANGE OF 98 TO AROUND
100...MOST LOCATIONS...LOOK GOOD.
/MONDAY NIGHT/
.SLIGHT CHANCE EVENING POPS MAINLY WEST...
IF SHOWERS AND THUNDERSTORMS DO DEVELOP TOMORROW...SOME MAY LINGER
ACROSS MAINLY OUR WEST COUNTIES TOMORROW EVENING. THUS...I DECIDED
TO CONTINUE 20 POPS FOR SOME OF OUR BIG COUNTRY COUNTIES AND A FEW
OTHER WESTERN COUNTIES. OTHERWISE...RAIN CHANCES END AND
TEMPERATURES DROP TO AROUND 75 FOR OVERNIGHT LOWS.
/TUESDAY THROUGH WEDNESDAY.
.DRY AND HOT...
MODELS STRENGTHEN THE RIDGE OVER THE REGION. CLOUD COVER WILL
DIMINISH. AFTERNOON HIGHS AND OVERNIGHT LOWS AROUND 100 AND
75...RESPECTIVELY...LOOK LIKELY.
LONG TERM...
/WEDNESDAY NIGHT THROUGH SUNDAY/
.DRY CONDITIONS CONTINUE WITH UNSEASONABLY HOT AFTERNOON HIGHS...
MODELS THIS CYCLE CONTINUE HIGH PRESSURE OVER THE REGION. MODELS
INDICATE THE 500 MB HIGH PRESSURE CENTER WILL MEANDER OVER OR NEAR
TEXAS THROUGH NEXT WEEKEND. AFTERNOON HIGHS MAINLY IN THE UPPER
90S TO AROUND 100...WHICH WE ALREADY IN OUR PREVIOUS FORECAST
PACKAGE...STILL LOOKS GOOD. OVERNIGHT LOWS MAY VARY A DEGREE OR
TWO. HOWEVER...NUMBERS CLOSE TO PERSISTENCE...MAINLY LOWER TO MID
70S...LOOK REASONABLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 92 75 98 76 99 / 5 20 20 5 5
SAN ANGELO 94 75 98 75 100 / 5 20 20 5 5
JUNCTION 94 75 97 75 98 / 5 10 10 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
607 PM CDT SUN JUL 28 2013
.SHORT TERM...(TONIGHT AND MONDAY)
ISSUED AT 250 PM CDT SUN JUL 28 2013
LATEST WATER VAPOR IMAGERY PLACED AN UPPER LEVEL LOW OVER THE
MICHIGAN...WITH WARM/MOIST AIR WRAPPING AROUND THE LOW RESULTING IN
WIDESPREAD CLOUDINESS FOR MOST OF WI. THE LOW WILL MEANDER SLOWLY
EAST TONIGHT...ALLOWING FOR A WEAK SFC HIGH OVER THE NORTHERN PLAINS
TO BUILD IN. THE UPPER LEVEL RIDGE AXIS STAYS WEST THROUGH 12Z MON.
EXPECT CLEARING WEST-EAST TONIGHT OF THE CLOUDS AS A RESULT. WITH
THE HIGH ALSO BRINGING IN LIGHT SFC WINDS...THE SPECTER OF RIVER
VALLEY FOG POKES OUT ITS HEAD. CLEAR SKIES...LIGHT WINDS AND RECENT
RAIN ALL FAVOR AT LEAST VALLEY FOG. ITS ALSO GETTING TO THE
CLIMATOLOGICAL FAVORED AUG-SEP-OCT PERIOD FOR RIVER VALLEY FOG.
THAT SAID...THE LOW LEVEL WIND FIELD COULD TEMPER THIS FOG POTENTIAL
QUITE A BIT. 12Z BUFKIT SOUNDINGS VIA THE NAM KEEPS THE WIND
STIRRED IN THE NEAR SFC LAYER...WITH AT LEAST 10 KTS AT 300 FT
THROUGH MIDNIGHT. THE RAP IS MORE BULLISH...HOLDING ONTO THESE
BREEZY NEAR SFC CONDITIONS THROUGH 3 AM. PRELIMINARY LOCAL RESEARCH
SUGGESTS THAT THIS DOES NOT FAVOR DENSE FOG FORMATION AT KLSE. WILL
STILL CONTINUE SOME MENTION OF FOG IN THE VALLEYS FOR EARLY MONDAY
MORNING...BUT IF WIND FIELDS STAY AS FORECAST...IT MAY BE MORE
PATCHY THEN WIDESPREAD.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 250 PM CDT SUN JUL 28 2013
THE BRIEF RETURN TO ZONAL FLOW QUICKLY TRANSITIONS TO NORTHWESTERLY
AS MODELS CONTINUE TO COME TO MORE OF A CONSENSUS ON TRACKING AN
UPPER LEVEL SHORTWAVE TROUGH ACROSS SOUTHERN CANADA. SOME
DIFFERENCES IN HOW FAR SOUTH IT DIPS...BUT BOTH THE ECMWF AND GFS
WOULD DRAG AN ASSOCIATED SFC FRONT ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY WED AFTERNOON. THE FRONT DOESN/T LOOK STRONGLY
CONVERGENT AT THIS MOMENT...WITH THE BETTER FORCING WITH THE
UPPER LEVEL SHORTWAVE. TIMING AND PLACEMENT OF THE VARIOUS WEATHER
FEATURES FOR NEXT WEEK HAVE BEEN ALL OVER THE MAP WITH THE
MODELS...SO CONFIDENCE ISN/T OVERLY HIGH WITH TIMING ON THIS FEATURE
YET. THERE IS AN INCREASE IN INSTABILITY/WIND SHEAR AHEAD OF THE
FRONT...AND WHILE NOT OVERTLY HIGH...COULD SUPPORT STRONG/ISOLATED
SEVERE STORMS IF TIMING IS RIGHT.
FRIDAY IS A PERIOD OF CONTENTION FOR THE MODELS...WITH THE 28.12Z
ECMWF CONTINUING TO POINT TO SOME PCPN POTENTIAL FOR AT LEAST THE
SOUTHERN 1/2 OF THE FORECAST AREA. THIS IS MOSTLY ASSOCIATED WITH AN
ANTICIPATED OVERNIGHT THUNDERSTORM COMPLEX OVER THE
PLAINS...TRACKING EAST WITH A RIPPLE IN THE UPPER LEVEL FLOW. GEM IS
SIMILAR TO THE EC WITH SOME RAIN CHANCES ACROSS THE SOUTH...ALTHOUGH
KEEPS THE HIGHER QPF AMOUNTS SOUTH OF THE FORECAST AREA. THE LATEST
GFS KEEPS IT ALL SOUTH...WHICH IS A BIG SHIFT SOUTHWARD COMPARED TO
ITS PREVIOUS RUNS. THAT SAID...BOTH THE EC AND GEM ARE TRENDING
SOUTHWARD WITH THEIR RESPECTIVE QPF FIELDS. WILL CONTINUE PCPN
CHANCES FOR FRI...WITH THE HIGHER CHANCES ACROSS THE SOUTH. TRENDS
MAY EVENTUALLY LEAD TO A DRY FORECAST ACROSS THE NORTH.
TEMPERATURES WILL BE REBOUNDING THIS WEEK AS THE ANOMALOUSLY COLD
AIR EXITS EAST WITH THE UPPER LEVEL TROUGH. STILL...THE PATTERN
FAVORS KEEPING TEMPS A FEW DEGREES ABOVE THE LATE JULY/EARLY AUGUST
NORMALS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 607 PM CDT SUN JUL 28 2013
AN AREA OF LOW PRESSURE AT THE SURFACE EXTENDS FROM EASTERN LAKE
SUPERIOR INTO LOWER MICHIGAN. THE LOW WILL CONTINUE TO MOVE EAST
INTO LOWER ONTARIO OVERNIGHT ALLOWING HIGH PRESSURE TO BUILD OVER
THE REGION. THIS WILL ALLOW THE CYCLONIC FLOW TO RELAX AND THE
CLOUDS TO DISSIPATE...ESPECIALLY WITH THE LOSS OF DAYTIME HEATING.
ALREADY SEEING SIGNS OF THIS ON THE WESTERN EDGE OF THE CLOUDS AS
THEY ARE SCATTERING OUT OVER EASTERN MINNESOTA. PLAN TO START KRST
WITH JUST SOME SCATTERED CLOUDS...ALTHOUGH THERE COULD STILL BE
SOME IN AND OUT VFR CEILINGS FOR A COUPLE OF HOURS THIS EVENING.
WILL START KLSE WITH A VFR CEILING BUT EXPECT THESE CLOUDS TO
SCATTER OUT BY MID EVENING. WITH THE MOSTLY CLEAR SKIES
OVERNIGHT...GOOD COOLING WILL OCCUR AND THE 28.18Z NAM IS
SUGGESTING THE POTENTIAL FOR VALLEY FOG TO FORM AT KLSE. THE NAM
ALSO SHOWS WINDS TO DECREASE TO LESS THAN 10 KNOTS UP THROUGH
ABOUT 3K FEET. THE 28.21Z RAP IS NOT AS FAVORABLE FOR FOG
FORMATION AS ITS LAYER OF LIGHTER WINDS ONLY EXTENDS UP TO 2K FEET
AND DOES SHOW SATURATION OCCURRING AT THE SURFACE. WHILE THE
28.18Z GFS HAS A VERY DEEP LAYER OF LIGHT WINDS IT ALSO DOES NOT
SATURATE AT THE SURFACE. WITH MIXED SIGNALS IN THE MODELS WILL
MAINTAIN CONTINUITY IN THE FORECAST WITH MVFR VISIBILITY FROM SOME
FOG AND MONITOR CONDITIONS THROUGH THE EVENING TO MAKE ANY
ADJUSTMENTS WITH THE NEXT FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
331 AM CDT SAT JUL 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CDT SAT JUL 27 2013
THE MAIN QUESTIONS FOR TODAY/TONIGHT ARE WITH HOW COLD IT WILL BE
ALONG WITH HOW FAR SOUTHWEST WILL THE RAIN SHOWERS MAKE IT.
CURRENTLY...A CLOSED MID LEVEL LOW CONTINUES TO SLOWLY DRIFT
ACROSS LAKE SUPERIOR WITH THREE MAIN SHORTWAVE TROUGHS ROTATING
AROUND IT LIKE SPOKES ON A WHEEL. THE SOUTHWESTERN SHORTWAVE HAS
HELPED TO PULL THE COLD CORE OF THE LOW SOUTHWARD ACROSS WESTERN
WISCONSIN. THIS HAS ALSO BROUGHT A LOW TO MID LEVEL BROKEN CLOUD
DECK AND SPORADIC VERY LIGHT RAIN SHOWERS DOWN WITH IT.
FOR TODAY...TEMPERATURES WILL GREATLY RELY UPON HOW MUCH CLOUD
COVER DEVELOPS. BASED ON 27.00Z NAM/GFS AND 27.06Z HRRR/RAP RH
FIELDS...EXPECT THAT THE MORE BROKEN TO OVERCAST CLOUD COVER WILL
BE ACROSS WESTERN WISCONSIN UNDER THE CORE OF THE LOW WITH IT
BECOMING MORE SCATTERED THE FURTHER SOUTHWEST YOU GO TOWARD IOWA.
AS A BASE FOR TEMPERATURES TODAY...MIXED DOWN FROM AROUND 850MB
DURING THE PEAK DIURNAL HEATING THIS AFTERNOON AND THEN ADJUSTED
DOWN A BIT BASED ON HOW OVERCAST CLOUD COVER IS. DOING THIS
YIELDS HIGHS IN THE UPPER 50S TO LOW 60S IN WESTERN TO NORTH
CENTRAL WISCONSIN AND LOW TO MID 60S INTO NORTHEAST IOWA. BASED ON
THESE HIGHS...SOME RECORD LOW MAXIMUM TEMPERATURES ARE IN DANGER
OF BEING BROKEN TODAY...SEE THE CLIMATE SECTION BELOW FOR LOCAL
RECORDS. GIVEN THE STEEP LOW LEVEL LAPSE RATES...RAIN SHOWERS ARE
EXPECTED BUT WILL BE ISOLATED TO SCATTERED AT TIMES TODAY.
EXPECT THAT SOME SHOWERS WILL PERSIST INTO TONIGHT...PARTICULARLY
IN NORTH CENTRAL WISCONSIN WHERE CLOUD COVER WILL ALSO BE MORE
PREVALENT. COULD BE PUSHING SOME RECORD LOWS...BUT THAT MAINLY
DEPENDS ON WHETHER SKIES CAN CLEAR OUT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 331 AM CDT SAT JUL 27 2013
THE LOW WILL START TO DRIFT EAST ACROSS THE GREAT LAKES ON SUNDAY
WITH GRADUALLY WARMING CONDITIONS EACH DAY INTO WEDNESDAY. SOME
SHOWERS COULD HANG ON ACROSS WESTERN WISCONSIN ON SUNDAY...BUT A
RIDGE OF HIGH PRESSURE WILL PUSH IN FROM THE WEST INTO MONDAY AND
BRING AN END TO THEM.
TUESDAY THEN APPEARS TO BE THE NEXT CHANCE FOR A MORE WIDESPREAD
RAINFALL...THOUGH CONFIDENCE IS NOT VERY HIGH IN THIS OCCURRING.
THE STRONGEST FORCING APPEARS TO SPLIT THE REGION AS ONE MID LEVEL
SHORT WAVE TROUGH TRACKS ACROSS SOUTHERN CANADA AND ANOTHER GOES
THROUGH MISSOURI. THE 27.00Z GEM IS THE MOST WIDESPREAD WITH ITS
QPF AS THE COLD FRONT/TROUGH COMES THROUGH WITH THE REST OF THE
27.00Z GUIDANCE REALLY BACKING OFF. SO...HAVE KEPT THE CHANCES IN
ON TUESDAY FOR NOW. THE BETTER CHANCE COULD COME ON WEDNESDAY AS
THE MAIN COLD FRONT DROPS THROUGH DURING PEAK HEATING.
AFTER A RIDGE OF HIGH PRESSURE MOVES IN ON THURSDAY...THE NEXT
SHOT FOR PRECIPITATION COMES IN ON FRIDAY ALONG A BAND OF WARM AIR
ADVECTION AHEAD OF THE NEXT SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1137 PM CDT FRI JUL 26 2013
LARGE AREA OF CLOUDS IN THE CYCLONIC FLOW REMAINS OVER MUCH
WISCONSIN AND EASTERN MINNESOTA. CEILINGS FOR THE MOST PART ARE
VFR OVER MINNESOTA BUT BECOME MVFR IN WISCONSIN. KLSE ALREADY HAS
HAD A SHORT PERIOD OF MVFR AND OBSERVATIONS AT 04Z INDICATE A
PRETTY SOLID MVFR DECK NORTH OF I94. THE 27.03Z RAP SUGGESTS THESE
LOWER CEILINGS WILL CONTINUE TO PROGRESS SOUTHWARD AND HAVE TAKEN
KLSE DOWN TO MVFR BASED ON THIS. WITH SOME HEATING AND MIXING
SATURDAY MORNING...THE CEILINGS SHOULD GO BACK UP TO VFR AND STAY
THERE FOR THE REMAINDER OF THE PERIOD. WILL LIKELY ALSO SEE SOME
GUSTS TO AROUND 20 KNOTS AGAIN DURING THE LATE MORNING AND
AFTERNOON. THE 27.00Z NAM CONTINUES TO SUGGESTS THAT ANY SHOWERS
THAT DEVELOP IN THE CYCLONIC FLOW WILL REMAIN NORTHEAST OF BOTH
TAF SITES AND WILL CONTINUE WITH A DRY FORECAST.
&&
.CLIMATE...WEEKEND
ISSUED AT 331 AM CDT SAT JUL 27 2013
THROUGH THE WEEKEND...THERE WILL BE POSSIBILITY FOR RECORD COLD
MAXIMUMS AND COLD MINIMUMS. HERE ARE SOME OF THE RECORDS FOR
THIS MORNINGS LOWS AND TODAYS HIGHS.
RECORD LOW TEMPERATURES FOR THIS MORNING...
AUSTIN MN 47 IN 1980
ROCHESTER MN 47 IN 1920
CHARLES CITY IA 47 IN 1971
DECORAH IA 46 IN 1962
MEDFORD WI 42 IN 1893
LA CROSSE WI 48 IN 1891
PRAIRIE DU CHIEN 45 IN 1911
SPARTA WI 42 IN 1971
RECORD LOW MAXIMUM TEMPERATURES FOR TODAY...
AUSTIN MN 67 IN 2005
ROCHESTER MN 64 IN 1981
CHARLES CITY IA 65 IN 1905
DECORAH IA 65 IN 1972
MEDFORD WI 62 IN 1945
LA CROSSE WI 69 IN 1981
PRAIRIE DU CHIEN 67 IN 1972
SPARTA WI 71 IN 2005
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...04
CLIMATE...BOYNE/HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1137 PM CDT FRI JUL 26 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 349 PM CDT FRI JUL 26 2013
AT 3 PM...A SURFACE LOW WAS LOCATED OVER NORTHEAST WISCONSIN. A
COLD FRONT EXTENDED SOUTHWEST FROM THIS LOW THROUGH THE WISCONSIN
DELLS AND THE EASTERN PORTIONS OF GRANT COUNTY. SCATTERED SHOWERS
AND THUNDERSTORMS WERE FOUND AHEAD OF THIS FRONT. A SECONDARY COLD
FRONT FROM MEDFORD WISCONSIN TO WOOD LAKE MINNESOTA. ALONG AND
BEHIND THIS FRONT...THERE WERE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS.
FOR TONIGHT...THE 26.12Z MODELS ARE IN GOOD AGREEMENT THAT THE
900 TO 700 MB LAYER WILL REMAIN FAIRLY SATURATED ACROSS WISCONSIN
OVERNIGHT. AS A RESULT KEPT SKIES MAINLY BROKEN. MEANWHILE IN
SOUTHEAST MINNESOTA AND NORTHEAST IOWA...IT IS LESS CLEAR SO WENT
WITH A SCATTERED TO BROKEN DECK OF CLOUDS IN THESE AREAS. WITH THE
MODELS SHOWING THAT THE ML CAPES QUICKLY DISSIPATING THIS
EVENING...JUST WENT WITH EVENING SHOWERS ALONG AND NORTH OF
INTERSTATE 94.
ON SATURDAY...THE MODELS SHOW THAT 850 MB TEMPERATURES WILL ONLY
RANGE FROM 3 TO 6C ACROSS WESTERN WISCONSIN AND 6 TO 8C IN
NORTHEAST IOWA AND SOUTHEAST MINNESOTA. THESE TEMPERATURES ARE 2
TO 3 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME OF YEAR...SO
EXPECTING RECORD OR NEAR RECORD MAXIMUM TEMPERATURES RANGING FROM
THE UPPER 50S TO MID 60S. NORMAL HIGH TEMPERATURES ARE IN THE
LOWER AND MID 80S. WITH 950 MB TO 800 MB LAPSE RATES OF 8 TO
10C/KM AND ML CAPES UP TO 100 J/KG...EXPECT ISOLATED TO SCATTERED
SHOWERS TO DEVELOP BY MID MORNING AND THEN CONTINUE INTO THE
AFTERNOON.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 349 PM CDT FRI JUL 26 2013
ON SATURDAY NIGHT...THE MODELS SHOW THAT A STRONG VORTICITY
MAXIMUM WILL MOVE SOUTHEAST ACROSS WISCONSIN. WITH GOOD 950 TO
650 MB...EXPECT THAT THE ISOLATED TO SCATTERED SHOWERS WILL
CONTINUE ACROSS WESTERN WISCONSIN. THE HIGHEST PRECIPITATION
CHANCES WILL EB FOUND NORTH OF THE INTERSTATE 94 CORRIDOR. THIS
VORT MAX WILL BE ACCOMPANIED WITH 2C 850 MB TEMPERATURES. THIS IS
2.5 TO 3 STANDARD DEVIATIONS BELOW NORMAL. FORTUNATELY IT LOOKS
LIKE THERE BE MAINLY MOSTLY CLOUDY SKIES ACROSS THE AREA OR WE
COULD BE POTENTIALLY LOOKING AT LOW TEMPERATURES FALLING TO AROUND
40 DEGREES. DUE TO THE CLOUDS...THESE TEMPERATURES WILL LIKELY
RANGE FROM THE MID 40S TO LOWER 50S.
ON SUNDAY...THE CLOSED 500 MB LOW OVER LAKE SUPERIOR WILL KEEP
UNUSUALLY 850 MB TEMPERATURES ACROSS THE REGION. 850 MB
TEMPERATURE ANOMALIES WILL RANGE FROM 2 TO 2.5 STANDARD DEVIATIONS
BELOW NORMAL. SINCE THE MOS TEMPERATURES TAKE IN CLIMATOLOGY...
STAYED AWAY FROM ANY BLEND THAT CONTAINED THEM AND WENT MORE WITH
A BLEND OF THE ACTUAL MODEL TEMPERATURES TO CAPTURE BETTER THE
UNUSUALLY COOL TEMPERATURES ACROSS THE REGION. LIKE SATURDAY...
THE 950 TO 800 MB LAPSE RATES WILL RANGE FROM 8 TO 10 C/KM AND ML
CAPES WILL CLIMB UP TO 100 J/KG ACROSS WESTERN WISCONSIN. DUE TO
THIS KEPT A MENTION OF ISOLATED TO SCATTERED SHOWERS.
ON MONDAY AND MONDAY NIGHT...THE MODELS ARE SHOWING 500 MB RIDGING
WILL DEVELOP IN THE WAKE OF THE CLOSED 500 MB LOW ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY. THIS WILL KEEP THE FRONTOGENESIS AND
BEST 850 MB MOISTURE TRANSPORT WELL TO OUR SOUTHWEST. WITH THE
EXCEPTION OF THE GEM...THE REMAINDER OF THE MODELS HAVE THE AREA
DRY FOR THIS TIME PERIOD. THIS MAKES A LOT SENSE WHEN CONSIDERING
THE DRY DEW POINTS ACROSS THE REGION...THUS...TOOK THE
PRECIPITATION CHANCES OUT OF THE FORECAST. IN ADDITION WITH THE
850 MB TEMPERATURES RUNNING 1 TO 2 STANDARD DEVIATIONS BELOW
NORMAL...STAYED AWAY FROM ANY BLEND WHICH CONTAINED THE MOS TO
BETTER REPRESENT THE COOLNESS RESIDING ACROSS THE REGION.
ON WEDNESDAY NIGHT...BOTH THE GFS AND ECMWF ARE IN AGREEMENT THAT
THERE WILL BE STRONG SUBSIDENCE ACROSS THE REGION IN THE WAKE OF
COLD FRONT FRONT. DUE TO THIS...REMOVED THE LOW PRECIPITATION
CHANCES THAT WERE IN THE ALL BLEND DATA BASE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1137 PM CDT FRI JUL 26 2013
LARGE AREA OF CLOUDS IN THE CYCLONIC FLOW REMAINS OVER MUCH
WISCONSIN AND EASTERN MINNESOTA. CEILINGS FOR THE MOST PART ARE
VFR OVER MINNESOTA BUT BECOME MVFR IN WISCONSIN. KLSE ALREADY HAS
HAD A SHORT PERIOD OF MVFR AND OBSERVATIONS AT 04Z INDICATE A
PRETTY SOLID MVFR DECK NORTH OF I94. THE 27.03Z RAP SUGGESTS THESE
LOWER CEILINGS WILL CONTINUE TO PROGRESS SOUTHWARD AND HAVE TAKEN
KLSE DOWN TO MVFR BASED ON THIS. WITH SOME HEATING AND MIXING
SATURDAY MORNING...THE CEILINGS SHOULD GO BACK UP TO VFR AND STAY
THERE FOR THE REMAINDER OF THE PERIOD. WILL LIKELY ALSO SEE SOME
GUSTS TO AROUND 20 KNOTS AGAIN DURING THE LATE MORNING AND
AFTERNOON. THE 27.00Z NAM CONTINUES TO SUGGESTS THAT ANY SHOWERS
THAT DEVELOP IN THE CYCLONIC FLOW WILL REMAIN NORTHEAST OF BOTH
TAF SITES AND WILL CONTINUE WITH A DRY FORECAST.
&&
.CLIMATE...WEEKEND
ISSUED AT 349 PM CDT FRI JUL 26 2013
THROUGH THE WEEKEND...THERE WILL BE POSSIBILITY FOR RECORD COLD
MAXIMUMS AND COLD MINIMUMS. HERE ARE SOME OF THE RECORDS FOR
TONIGHT AND SATURDAY.
RECORD LOW TEMPERATURES FOR TONIGHT...
AUSTIN MN 47 IN 1980
ROCHESTER MN 47 IN 1920
CHARLES CITY IA 47 IN 1971
DECORAH IA 46 IN 1962
MEDFORD WI 42 IN 1893
LA CROSSE WI 48 IN 1891
PRAIRIE DU CHIEN 45 IN 1911
SPARTA WI 42 IN 1971
RECORD LOW MAXIMUM TEMPERATURES FOR SATURDAY...
AUSTIN MN 67 IN 2005
ROCHESTER MN 64 IN 1981
CHARLES CITY IA 65 IN 1905
DECORAH IA 65 IN 1972
MEDFORD WI 62 IN 1945
LA CROSSE WI 69 IN 1981
PRAIRIE DU CHIEN 67 IN 1972
SPARTA WI 71 IN 2005
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
CLIMATE...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
839 PM MDT SUN JUL 28 2013
.UPDATE...
ISSUED AT 831 PM MDT SUN JUL 28 2013
SHOWERS AND THUNDERSTORMS LATE THIS EVENING ARE BECOMING MORE
ISOLATED AND ARE MAINLY CONFINED WELL NORTH OF I80. LOWERED POP
THROUGH MIDNIGHT ACROSS MOST OF THE AREA WITH ISOLATED TSTORMS
STILL POSSIBLE EAST OF THE NORTHERN LARAMIE RANGE INTO WESTERN
NEBRASKA. LOW CLOUDS AND PATCHY FOG IS EXPECTED TO DEVELOP IN THE
NEXT FEW HOURS OVER THE SOUTHERN NEBRASKA PANHANDLE AND EVENTUALLY
PUSH WESTWARD INTO CHEYENNE AND THE SOUTHERN LARAMIE RANGE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM MDT SUN JUL 28 2013
AFTERNOON GOES WATER VAPOR IMAGERY ANIMATION SHOWED THE CENTER OF
THE UPPER RIDGE OVER NORTHERN MEXICO. UPPER TROUGHS WERE LOCATED
OVER WEST CENTRAL CANADA AND THE WESTERN GREAT LAKES. ABUNDANT
SUBTROPICAL MOISTURE COURTESY OF THE MONSOON FLOW AROUND THE RIDGE
WAS FUELING SCATTERED CONVECTION FROM THE SOUTHERN GREAT BASIN
ACROSS THE ROCKIES. A STALLED SURFACE FRONT EXTENDED FROM THE BIG
HORN RANGE SOUTHEAST TO THE LEE OF THE LARAMIE RANGE INTO EASTERN
COLORADO. ANOTHER FRONT WAS LOCATED FROM EAST CENTRAL MONTANA TO
CENTRAL IDAHO AND NORTHERN NEVADA. REGIONAL LAPS SHOWED SBCAPES
OF 400-800 J/KG OVER MUCH OF SOUTHEAST WYOMING. SCATTERED TSTORMS
WILL CONTINUE TO DEVELOP ALONG AND EAST OF THE MOUNTAINS FOR THE
REMAINDER OF THE AFTERNOON. THE STRONGER TSTORMS MAY CONTAIN BRIEF
HEAVY RAIN...SMALL HAIL AND WIND GUSTS TO 40 MPH.
CONVECTIVE COVERAGE AND INTENSITY WILL DIMINISH FROM WEST TO EAST
THIS EVENING WITH THE LOSS OF DAYTIME HEATING. THE NAM DEPICTS
SOME RESIDUAL LIGHT QPF GOING OVERNIGHT OVER THE MOUNTAINS AND
HIGH PLAINS...SO HAVE SLIGHT CHANCE POPS FOR RAIN SHOWERS. NAM...
HRRR AND SREF PROGS USHER IN LOW CLOUDS AND PATCHY FOG OVERNIGHT
INTO EARLY MONDAY MORNING ACROSS EXTREME SOUTHEAST WYOMING AND THE
SOUTHERN NEB PANHANDLE. LATER MONDAY MORNING...ISOLATED CONVECTION
DEVELOPS NORTH AND WEST OF THE LARAMIE RANGE...INCREASES IN
COVERAGE WHILE SPREADING EAST ONTO THE PLAINS IN THE AFTERNOON.
THIS IS IN RESPONSE TO A SHORTWAVE MOVING NORTHEAST FROM UTAH INTO
WYOMING. PRECIP WATER VALUES WILL RANGE FROM 1 TO 1.25 INCHES EAST
OF THE LARAMIE RANGE...AND AROUND 0.75 INCHES TO THE WEST. AFTERNOON
SBCAPES EAST OF THE LARAMIE RANGE PEAK FROM 500-1000 J/KG. THE
POTENTIAL FOR LOCALLY HEAVY RAIN AND GUSTY WINDS WILL EXIST WITH
THE STRONGER STORMS THAT MOVE EAST ACROSS THE PLAINS. INDICATIONS
ARE THAT ISOLATED CONVECTION MAY LINGER PAST MIDNIGHT MONDAY NIGHT
ACROSS EAST CENTRAL WYOMING INTO WESTERN NEBRASKA WHERE FORCING
FROM PASSING WEAK UPPER JET ENERGY FOCUSES LIFT. TUESDAY WILL BE
A CARBON COPY OF MONDAY WITH SCATTERED TSTORMS MOST AREAS DURING
THE AFTERNOON. THREAT FOR STRONG OR SEVERE TSTORMS WILL BE JUST
EAST OF THE CWA WHERE INSTABILITY WILL BE HIGHEST. ONLY SLIGHT
DAY-TO-DAY MODERATION OF 700MB TEMPERATURES YIELDS SEASONAL HIGH
TEMPERATURES IN THE 80S...WITH 60S AND 70S FOR HIGHER ELEVATIONS.
LOW TEMPERATURES WILL BE IN THE 50S TO LOWER 60S...WITH 40S FOR
HIGHER ELEVATIONS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 200 PM MDT SUN JUL 28 2013
MAIN FORECAST CONCERN WILL BE CONTINUING RISK OF AFTN CONVECTION
WITH REMAINING MOISTURE ACROSS THE CWA. BY TUE NIGHT...GFS AND
ECMWF SHOW A UPPER LOW DEVELOPING OFF PAC NW COAST NEAR WA/OR. THE
SUBTROPICAL RIDGE AXIS WILL BE OVER WCNTRL WY WITH NW FLOW ALOFT.
AS HAS BEEN THE CASE THIS SUMMER...ANOTHER SHORTWAVE MOVING THROUGH
SRN CANADA WILL SHIFT A FRONTAL BOUNDARY SOUTH WITH SE UPSLOPE FLOW
PUSHING TOWARD LARAMIE RANGE FOR AFTN CONVECTION ON WED. BY THU...
THE UPPER RIDGE AXIS WILL TEND TO FLATTEN AS SW FLOW ALOFT MOVES
INTO WRN WY. THE UPPER LOW ALONG WA/OR COAST WILL SHIFT SOME
SHORTWAVE ENERGY EAST OVER THE RIDGE...BUT MONSOON MOISTURE FLOW
WILL REMAIN MORE SW WITH PLAINS MOISTURE INTO NE PANHANDLE. HAVE
KEPT TREND OF AFTN CONVECTION WITH BEST CHC PCPN FARTHER NORTH AND
EAST. ON FRI AND SAT...SEVERAL SHORTWAVE FEATURES WORKING OUT OF
BAJA CA IN MONSOON FLOW WILL SHIFT ACROSS WY WITH PERSISTENT SE
SFC FLOW AND FRONTAL BOUNDARY REMAINING UP AGAINST THE LARAMIE
RANGE. HAVE INCREASED POPS ON FRI AND SAT. SFC LOW DEVELOPING IN
NRN WY WILL TEND TO FOCUS BEST PCPN NORTH...BUT STILL GOOD THETA-E
RIDGE AND SFC INSTABILITY ALONG AND EAST OF FRONTAL BOUNDARY FOR
CONVECTION INTO SUNDAY. TEMPS THROUGH THE PERIOD WILL WARM TO
NORMAL AND SLIGHTLY ABOVE BY THU AND FRI.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 510 PM MDT SUN JUL 28 2013
HAVE A PROLONGED LOW CLOUD UPSLOPE EVENT SETTING UP FOR TONIGHT
INTO MONDAY MORNING FOR THE SOUTHERN PANHANDLE AND EXTREME
SOUTHEAST WYOMING. SUFFICIENT LOW LEVEL MOISTURE COMBINED WITH
SOUTHEAST WINDS AND COOL TEMPERATURES SHOULD COMBINE TO CREATE IFR
CEILINGS ALONG AND SOUTH OF A LINE FROM ALLIANCE TO PROBABLY
WHEATLAND THIS EVENING. MVFR CEILINGS ALREADY BEING OBSERVED IN
THE SOUTHERN PANHANDLE. WITH LOSS OF DAYTIME HEATING AND COOLING
TEMPERATURES...LOOKING AT CEILINGS AT OR BELOW 500 FEET AGL.
LATEST HRRR RUN SHOWS IFR/LIFR CEILINGS AT KAIA AND KSNY AS EARLY
AS 03Z...SPREADING WEST TO KBFF AROUND 06Z AND KCYS SHORTLY
THEREAFTER. THESE LOW CEILINGS EXPECTED TO CONTINUE THROUGH ABOUT
15Z AND COULD PERSIST LONGER AT KSNY.
&&
.FIRE WEATHER...
ISSUED AT 224 PM MDT SUN JUL 28 2013
AN UPPER RIDGE TO THE SOUTH WILL GRADUALLY BUILD NORTHWARD ACROSS
THE ROCKIES EARLY THIS WEEK. THE MONSOON FLOW AROUND THE RIDGE WILL
CONTINUE TO ADVECT SUBTROPICAL MOISTURE ACROSS THE DISTRICTS...WITH
ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS. MINIMUM HUMIDITIES WILL VARY FROM 20 TO 30 PERCENT
EACH DAY...WITH GOOD TO EXCELLENT NIGHTTIME RECOVERIES. WINDS WILL
BE GUSTY AND ERRATIC IN AND NEAR THUNDERSTORMS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...TJT
SHORT TERM...JAMSKI
LONG TERM...SLA
AVIATION...CLAYCOMB
FIRE WEATHER...JAMSKI
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
516 PM MDT SUN JUL 28 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 315 PM MDT SUN JUL 28 2013
AFTERNOON GOES WATER VAPOR IMAGERY ANIMATION SHOWED THE CENTER OF
THE UPPER RIDGE OVER NORTHERN MEXICO. UPPER TROUGHS WERE LOCATED
OVER WEST CENTRAL CANADA AND THE WESTERN GREAT LAKES. ABUNDANT
SUBTROPICAL MOISTURE COURTESY OF THE MONSOON FLOW AROUND THE RIDGE
WAS FUELING SCATTERED CONVECTION FROM THE SOUTHERN GREAT BASIN
ACROSS THE ROCKIES. A STALLED SURFACE FRONT EXTENDED FROM THE BIG
HORN RANGE SOUTHEAST TO THE LEE OF THE LARAMIE RANGE INTO EASTERN
COLORADO. ANOTHER FRONT WAS LOCATED FROM EAST CENTRAL MONTANA TO
CENTRAL IDAHO AND NORTHERN NEVADA. REGIONAL LAPS SHOWED SBCAPES
OF 400-800 J/KG OVER MUCH OF SOUTHEAST WYOMING. SCATTERED TSTORMS
WILL CONTINUE TO DEVELOP ALONG AND EAST OF THE MOUNTAINS FOR THE
REMAINDER OF THE AFTERNOON. THE STRONGER TSTORMS MAY CONTAIN BRIEF
HEAVY RAIN...SMALL HAIL AND WIND GUSTS TO 40 MPH.
CONVECTIVE COVERAGE AND INTENSITY WILL DIMINISH FROM WEST TO EAST
THIS EVENING WITH THE LOSS OF DAYTIME HEATING. THE NAM DEPICTS
SOME RESIDUAL LIGHT QPF GOING OVERNIGHT OVER THE MOUNTAINS AND
HIGH PLAINS...SO HAVE SLIGHT CHANCE POPS FOR RAIN SHOWERS. NAM...
HRRR AND SREF PROGS USHER IN LOW CLOUDS AND PATCHY FOG OVERNIGHT
INTO EARLY MONDAY MORNING ACROSS EXTREME SOUTHEAST WYOMING AND THE
SOUTHERN NEB PANHANDLE. LATER MONDAY MORNING...ISOLATED CONVECTION
DEVELOPS NORTH AND WEST OF THE LARAMIE RANGE...INCREASES IN
COVERAGE WHILE SPREADING EAST ONTO THE PLAINS IN THE AFTERNOON.
THIS IS IN RESPONSE TO A SHORTWAVE MOVING NORTHEAST FROM UTAH INTO
WYOMING. PRECIP WATER VALUES WILL RANGE FROM 1 TO 1.25 INCHES EAST
OF THE LARAMIE RANGE...AND AROUND 0.75 INCHES TO THE WEST. AFTERNOON
SBCAPES EAST OF THE LARAMIE RANGE PEAK FROM 500-1000 J/KG. THE
POTENTIAL FOR LOCALLY HEAVY RAIN AND GUSTY WINDS WILL EXIST WITH
THE STRONGER STORMS THAT MOVE EAST ACROSS THE PLAINS. INDICATIONS
ARE THAT ISOLATED CONVECTION MAY LINGER PAST MIDNIGHT MONDAY NIGHT
ACROSS EAST CENTRAL WYOMING INTO WESTERN NEBRASKA WHERE FORCING
FROM PASSING WEAK UPPER JET ENERGY FOCUSES LIFT. TUESDAY WILL BE
A CARBON COPY OF MONDAY WITH SCATTERED TSTORMS MOST AREAS DURING
THE AFTERNOON. THREAT FOR STRONG OR SEVERE TSTORMS WILL BE JUST
EAST OF THE CWA WHERE INSTABILITY WILL BE HIGHEST. ONLY SLIGHT
DAY-TO-DAY MODERATION OF 700MB TEMPERATURES YIELDS SEASONAL HIGH
TEMPERATURES IN THE 80S...WITH 60S AND 70S FOR HIGHER ELEVATIONS.
LOW TEMPERATURES WILL BE IN THE 50S TO LOWER 60S...WITH 40S FOR
HIGHER ELEVATIONS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 200 PM MDT SUN JUL 28 2013
MAIN FORECAST CONCERN WILL BE CONTINUING RISK OF AFTN CONVECTION
WITH REMAINING MOISTURE ACROSS THE CWA. BY TUE NIGHT...GFS AND
ECMWF SHOW A UPPER LOW DEVELOPING OFF PAC NW COAST NEAR WA/OR. THE
SUBTROPICAL RIDGE AXIS WILL BE OVER WCNTRL WY WITH NW FLOW ALOFT.
AS HAS BEEN THE CASE THIS SUMMER...ANOTHER SHORTWAVE MOVING THROUGH
SRN CANADA WILL SHIFT A FRONTAL BOUNDARY SOUTH WITH SE UPSLOPE FLOW
PUSHING TOWARD LARAMIE RANGE FOR AFTN CONVECTION ON WED. BY THU...
THE UPPER RIDGE AXIS WILL TEND TO FLATTEN AS SW FLOW ALOFT MOVES
INTO WRN WY. THE UPPER LOW ALONG WA/OR COAST WILL SHIFT SOME
SHORTWAVE ENERGY EAST OVER THE RIDGE...BUT MONSOON MOISTURE FLOW
WILL REMAIN MORE SW WITH PLAINS MOISTURE INTO NE PANHANDLE. HAVE
KEPT TREND OF AFTN CONVECTION WITH BEST CHC PCPN FARTHER NORTH AND
EAST. ON FRI AND SAT...SEVERAL SHORTWAVE FEATURES WORKING OUT OF
BAJA CA IN MONSOON FLOW WILL SHIFT ACROSS WY WITH PERSISTENT SE
SFC FLOW AND FRONTAL BOUNDARY REMAINING UP AGAINST THE LARAMIE
RANGE. HAVE INCREASED POPS ON FRI AND SAT. SFC LOW DEVELOPING IN
NRN WY WILL TEND TO FOCUS BEST PCPN NORTH...BUT STILL GOOD THETA-E
RIDGE AND SFC INSTABILITY ALONG AND EAST OF FRONTAL BOUNDARY FOR
CONVECTION INTO SUNDAY. TEMPS THROUGH THE PERIOD WILL WARM TO
NORMAL AND SLIGHTLY ABOVE BY THU AND FRI.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 510 PM MDT SUN JUL 28 2013
HAVE A PROLONGED LOW CLOUD UPSLOPE EVENT SETTING UP FOR TONIGHT
INTO MONDAY MORNING FOR THE SOUTHERN PANHANDLE AND EXTREME
SOUTHEAST WYOMING. SUFFICIENT LOW LEVEL MOISTURE COMBINED WITH
SOUTHEAST WINDS AND COOL TEMPERATURES SHOULD COMBINE TO CREATE IFR
CEILINGS ALONG AND SOUTH OF A LINE FROM ALLIANCE TO PROBABLY
WHEATLAND THIS EVENING. MVFR CEILINGS ALREADY BEING OBSERVED IN
THE SOUTHERN PANHANDLE. WITH LOSS OF DAYTIME HEATING AND COOLING
TEMPERATURES...LOOKING AT CEILINGS AT OR BELOW 500 FEET AGL.
LATEST HRRR RUN SHOWS IFR/LIFR CEILINGS AT KAIA AND KSNY AS EARLY
AS 03Z...SPREADING WEST TO KBFF AROUND 06Z AND KCYS SHORTLY
THEREAFTER. THESE LOW CEILINGS EXPECTED TO CONTINUE THROUGH ABOUT
15Z AND COULD PERSIST LONGER AT KSNY.
&&
.FIRE WEATHER...
ISSUED AT 224 PM MDT SUN JUL 28 2013
AN UPPER RIDGE TO THE SOUTH WILL GRADUALLY BUILD NORTHWARD ACROSS
THE ROCKIES EARLY THIS WEEK. THE MONSOON FLOW AROUND THE RIDGE WILL
CONTINUE TO ADVECT SUBTROPICAL MOISTURE ACROSS THE DISTRICTS...WITH
ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS. MINIMUM HUMIDITIES WILL VARY FROM 20 TO 30 PERCENT
EACH DAY...WITH GOOD TO EXCELLENT NIGHTTIME RECOVERIES. WINDS WILL
BE GUSTY AND ERRATIC IN AND NEAR THUNDERSTORMS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...JAMSKI
LONG TERM...SLA
AVIATION...CLAYCOMB
FIRE WEATHER...JAMSKI
AREA FORECAST DISCUSSION
NWS TAUNTON MA
356 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT MOVES ACROSS THE REGION TODAY...POSSIBLY TRIGGERING
AN ISOLATED SHOWER ESPECIALLY ACROSS EASTERN MASSACHUSETTS AND
RHODE ISLAND. HIGH PRESSURE BUILDS INTO THE NORTHEAST TONIGHT
THROUGH WED...DELIVERING DRY WEATHER TO THE AREA ALONG WITH
COMFORTABLE TEMPERATURES AND HUMIDITY. ANOTHER FRONTAL SYSTEM
APPROACHES NEW ENGLAND THU AND FRI WITH SHOWERS LIKELY. COOLER AND
MAINLY DRY WEATHER ARE THE LATEST TRENDS FOR NEXT WEEKEND
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
4 AM UPDATE..
AREAS OF FOG HAVE DEVELOPED IN PORTIONS OF SOUTHERN NEW ENGLAND...IN
PARTICULAR EAST COASTAL MA. THE FOG WILL REDUCE VISIBILITY TO 1/2
MILE AT TIMES THROUGH 7 AM. THE FOG IS EXPECTED TO LIFT AND
DISSIPATE BY MID MORNING.
A COLD FRONT EXTENDING NORTH TO SOUTH THROUGH EASTERN NY AND NJ
IS EXPECTED TO PUSH INTO SOUTHERN NEW ENGLAND EARLY THIS MORNING.
MODELS INDICATE THAT THE SURFACE FRONT MAY TAKE THE ENTIRE DAY TO
PUSH THROUGH OUR AREA...POSSIBLY INTO THE EVENING ACROSS FAR
EASTERN ZONES. HOWEVER...PRONOUNCED MID LEVEL DRYING MOVES IN FROM
W TO E DURING THE LATE MORNING AND EARLY AFTERNOON ACROSS OUR
AREA. NAM AND RAP INDICATE PWATS FALL TO AROUND AN INCH BY 18Z IN
WESTERN HALF OF THE FORECAST AREA...GFS PUSHES IN DRIER AIR
QUICKER. WITH APPROACH OF FROPA AND SCATTERED LINGERING SHOWERS
ALONG AND AHEAD OF THE FRONT IT IS PRUDENT TO START OFF THE DAY
WITH CHANCE POPS. THEN WITH MODELS INTRODUCING SIGNIFICANT MID
LEVEL DRYING WILL GRADUALLY DROP OFF POPS FROM WEST TO EAST...WITH
ONLY A SLIGHT CHANCE POP E COASTAL MA AND VICINITY DURING EARLY-
MID AFTERNOON WITH THE ADDED POSSIBILITY THERE THAT SEA BREEZE
DEVELOPMENT COULD HELP TRIGGER SOME SHOWERS.
CONSIDERABLE CLOUDINESS TO START OFF THE DAY WITH A MIX OF STRATUS
AND CONVECTIVE DEBRIS CLOUDS...THEN GRADUAL DECREASE IN CLOUDS
EXPECTED FROM WEST TO EAST.
USING A BLEND OF MAV/MET GUIDANCE WITH MAX TEMPS IN THE LOW TO MID
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
MONDAY NIGHT...COLD FRONT MOVES OFFSHORE...WHILE HIGH PRESSURE
BUILDS OVER THE OHIO VALLEY. MOSTLY CLEAR SKIES WITH MIN TEMPS OF
55 TO 65 DEGREES...COOLEST OVER THE FAR INTERIOR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...
* TEMPS AT OR SLIGHTLY COOLER THAN NORMAL
* SHOWERS LIKELY LATE THU INTO FRI
* NEXT WEEKEND IS TRENDING COOLER BUT MAINLY DRY
SYNOPTIC OVERVIEW...
GOOD MODEL AGREEMENT AMONG THE ECENS AND GEFS ENSEMBLES ON THE
NORTHERN STREAM JET REMAINING AMPLIFIED AND SUPPRESSED ACROSS THE
GREAT LAKES AND NEW ENGLAND THIS PERIOD. THIS WILL RESULT IN A STORM
TRACK ACROSS OR SOUTH OF THE REGION...YIELDING AN ACTIVE WEATHER
PATTERN FOR THE AREA BUT CONFINING ANY SEVERE WEATHER THREAT AND
EXCESSIVE HEAT WELL SOUTH AND SOUTHWEST OF NEW ENGLAND. THIS IS
SUPPORTED BY LATEST TELECONNECTIONS WITH NAO AND AO REMAINING WEAKLY
NEGATIVE DURING THIS FORECAST PERIOD.
SENSIBLE WEATHER...
TUE...
SIGNIFICANT AIRMASS CHANGE BEHIND MON NIGHT/S COLD FRONT WITH PWATS
DIPPING BELOW 1 INCH AND DEW PTS FALLING INTO THE U40S TO L50S!
REFRESHING WNW WIND TO ACCOMPANY THE COOLER/LESS HUMID AIRMASS TUE.
PGRAD LOOKS ROBUST ENOUGH TO PRECLUDE ANY SEABREEZES.
WED...
RIDGE OF HIGH PRES CREST OVER THE REGION AROUND 12Z...THEN SLIPPING
OFFSHORE. THIS WILL RESULT IN A COOL START BUT TEMPS WILL REBOUND
QUICKLY AS STRONG JULY SUNSHINE COMBINES WITH WEAK WARM AIR
ADVECTION AS RETURN FLOW GETS UNDERWAY. DEW PTS WILL INCH UPWARD
ESPECIALLY ALONG THE SOUTH COAST...BUT STILL ANOTHER GEM OF A DAY
WITH PLENTY OF SUNSHINE AND COMFORTABLE TEMPS AND HUMIDITY.
THU/FRI...
NEXT SHORT WAVE AND ATTENDING FRONTAL BOUNDARY APPROACHES THE REGION
LATE THU INTO FRI. FAIRLY AMPLIFIED TROUGH WITH NEGATIVE TILT. ALL
MODELS ESPECIALLY THE ECMWF SUGGEST THIS STRONG FORCING FOR ASCENT
WILL INDUCE A FRONTAL WAVE AND TRACK ALONG OR SOUTH OF NEW ENGLAND.
MORE LIKE A COOL SEASON EVENT THAN A TYPICAL SUMMER FRONTAL SYSTEM.
MODELS ALSO ADVERTISING SOME ELEVATED INSTABILITY ALONG WITH GOOD
MOISTURE ADVECTION AS PWATS CLIMB ABOVE 1.5 INCHES. ALL OF THESE
ATTRIBUTES SUGGEST A RISK FOR ENHANCED QPF. AS FOR TIMING...
SURPRISINGLY AT THIS TIME RANGE ENSEMBLES AND DETERMINISTIC GUID IN
GOOD AGREEMENT WITH HIGHEST PROBABILITY OF RAIN/SHOWERS FROM LATE
THU INTO EARLY FRI. IN FACT 00Z GEFS ENSEMBLES OFFERING LIKELY POPS
DURING THIS TIME PERIOD. TEMPS HERE WILL LIKELY BE ON THE COOL SIDE
GIVEN CLOUD COVER/RAIN AND ESPECIALLY IF SURFACE WAVE TRACKS SOUTH
OF THE REGION.
SAT/SUN...
ECENS AND GEFS ENSEMBLES BOTH HAVE POLAR VORTEX MOVING EQUATORWARD
INTO SOUTH-CENTRAL QUEBEC WITH HEIGHTS OVER NEW ENGLAND DIPPING TO
MINUS 2 STANDARD DEVIATIONS FROM CLIMO! THIS WILL SUPPORT COOLER
TEMPS. DETERMINISTIC RUNS OF THE GFS AND ECMWF ARE EVEN MORE ROBUST.
AS FOR PRECIP...PATTERN SUGGEST DRY WEATHER WITH STORM TRACK
SUPPRESSED SOUTH OF NEW ENGLAND. HOWEVER GIVEN COLD AIR ALOFT CAN/T
RULE OUT ISOLATED DIURNAL SHOWER/TSTM ESPECIALLY HIGHER TERRAIN.
FOR NEXT WEEK ALL MODEL GUID INDICATING POTENTIAL RECORD COOL TEMPS
FOR NEW ENGLAND AS POLAR VORTEX MAY CONTINUE TO DIG SOUTHWARD
THROUGH QUEBEC.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERALL...MODERATE CONFIDENCE BUT LOW CONFIDENCE ON CAPE/ISLANDS.
TODAY...ACROSS EAST COASTAL MA IFR/LIFR CIGS/VSBYS TO START IN
STRATUS AND FOG...IMPROVING TO MVFR AFTER 12-13Z...THEN IMPROVING TO
VFR BY 18Z. ON CAPE/AND ISLANDS A PERIOD OF IFR CONDITIONS IS
EXPECTED TO FORM PRIOR TO 12Z AND LAST FOR A FEW HOURS...THEN CIGS
IMPROVE TO VFR BY 18Z. OVER THE INTERIOR...MVFR/LOCALIZED IFR
CIGS/VSBYS IN FOG IMPROVE TO VFR AFTER 12Z. ISOLD-SCT SHOWERS DURING
THE MORNING...AND EARLY AFTERNOON EAST COASTAL MA THRU 19Z.
TONIGHT...HIGH CONFIDENCE VFR.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. IFR/LIFR CIGS/VSBYS
PERSIST THRU 13Z...THEN CIGS/VSBYS GRADUALLY IMPROVE AFTER 13Z. CIGS
IMPROVE TO VFR BY 18Z.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS/VSBYS SHOULD
DEVELOP FOR A PERIOD OF TIME EARLY THIS MORNING...BECOMING VFR BY
13Z. SCATTERED SHOWERS POSSIBLE THRU 15Z.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...HIGH CONFIDENCE FOR VFR AND DRY WEATHER. SEABREEZES
LIKELY WED.
THU AND FRI...A PERIOD OF MVFR/IFR POSSIBLE ALONG WITH SHOWERS
LIKELY. HIGH CONFIDENCE ON SHOWERS BUT LOWER CONFIDENCE ON EXACT CIG
AND VSBY CATEGORIES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE.
TODAY...COLD FRONT APPROACHES THE WATERS TODAY BUT WINDS ARE
EXPECTED TO BE 15KT OR LESS. SEAS ON THE SOUTHERN OUTER COASTAL
WATERS EXPECTED TO PRIMARILY BE 2 TO 4 FT BUT THERE IS A CHANCE FOR
5 FT SEAS FOR A SHORT TIMEFRAME.
TONIGHT...WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA THRESHOLDS.
COLD FRONT CROSSES THE WATERS WITH WINDS BECOMING NW AROUND 10 KT
AFTER MIDNIGHT.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...FINE BOATING WEATHER WITH HIGH PRES IN CONTROL OF THE
NORTHEAST. TRANQUIL SEAS GIVEN LIGHT WINDS AND SMALL SWELLS. GOOD
VSBY AS WELL.
THU AND FRI...STRONG FRONTAL SYSTEM AND SURFACE WAVE LIKELY WITH LOW
TRACKING ALONG OR NEAR SOUTHERN NEW ENGLAND COAST. SHOWERS AND FOG
WILL YIELD POOR VSBY. LOW CONFIDENCE ON WIND FORECAST GIVEN
UNCERTAINTY ON EXACT TRACK AND INTENSITY OF LOW.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/NMB
NEAR TERM...NMB
SHORT TERM...NMB
LONG TERM...NOCERA
AVIATION...NOCERA/NMB
MARINE...NOCERA/NMB
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
407 AM EDT Mon Jul 29 2013
.NEAR TERM [Through Tonight]...
The anomalously deep eastern U.S. long wave trough is beginning to
lose amplitude across the Southeastern U.S. as the parent low drifts
northeast into Canada. There are no obvious upstream short waves
that will impact the area today. In fact, we will see some influence
today from a weak upper high over LA. At the surface, a very weak
low is still analyzed near the MS/AL coast with a trough extending
east from it into our coastal waters and then northeast across the
FL Big Bend and South Central GA. Area radars are showing isolated
showers developing east of the low and north of the trough over the
FL Panhandle. A cold front is analyzed across central portions of AL
and MS. Showers and thunderstorms are expected to be less numerous
today across our northwestern zones and somewhat drier air filters
in to the north and we see a lack of upper level support. To the
east, the presence of the surface trough and onshore flow ahead of
the weak low should result in somewhat higher PoPs of about 40
percent in the TLH-VLD corridor. Afternoon max temperatures will be
within a degree or so of normal, mainly in the lower 90s. Coastal
areas will be held to the upper 80s due to the sea breeze.
&&
.SHORT TERM [Tuesday Through Wednesday Night]...
Deep layer ridging will be present during the start of the short
term period. This will usher in drier air, giving way to slightly
above average temperatures and reduced PoPs. On Tuesday
the highest PoPs will be confined to our far eastern CWA
where some residual moisture ahead of a weak surface trough will
be present. During the day on Wednesday an upper level shortwave
will move through our CWA, increasing mid-level moisture feed. Model
guidance is indicating a weak surface reflection associated with
the shortwave, which coupled with enhanced mid-level moisture will
enhance PoPs to levels at or above climatology normals.
&&
.LONG TERM [Thursday through Sunday]...
As was expected, the upper level ridge will not be around the CWA
for too long as it initially retrogrades westward into the desert
Southwest, reestablishing the all too familiar trof across the
region. This is expected to result in an above climo period of
PoPs (40-60% conservatively) at the moment for Thursday and near
climo temps. This ridge may head back eastward for the end of the
week and weekend, resulting in another seemingly rare warm up and
decrease in PoPs.
&&
.AVIATION...
[Through 06 UTC Tuesday] Hi res guidance including the HRRR indicate
that there is a change for low cigs, most likely IFR at DHN and MVFR
at ABY and we have only included this at those two terminals and
removed from VLD. Showers are expected to get an early start at ECP
and TLH. we maintained the inherited probabilities for TS at these
two terminals and VLD. Convective coverage is too low to include any
mention of TS at DHN and ABY for this afternoon.
&&
.MARINE...
A weak surface low located off the coast of Mississippi will
slowly drift southeast and dissipate. High pressure will build over
our coastal waters giving way to typical summertime winds and
seas.
&&
.FIRE WEATHER...
Red Flag conditions are not anticipated this week.
&&
.HYDROLOGY...
In general, all area rivers currently in "Action" or flood stage
should either remain steady or gradually continue to lower over the
next several days. Widespread heavy rains are not anticipated,
though scattered heavy showers will be possible. Should one of these
storms form over or just upstream of our river system, sharp rises
will be possible. This was evident this afternoon along the Pea
River. The most notable river currently in flood is the
Choctawhatchee River near Bruce, which is expected to remain in
moderate flood stage through at least Thursday morning.
More specific stage information, as well as the latest river
forecasts can be found at the following link:
http://goo.gl/Lpg4a1
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 92 72 95 72 91 / 40 20 30 20 40
Panama City 90 76 90 77 88 / 30 20 30 20 30
Dothan 93 72 96 72 92 / 20 20 20 20 40
Albany 93 72 96 72 92 / 30 20 20 20 40
Valdosta 92 70 97 72 91 / 40 30 40 30 40
Cross City 93 70 94 72 90 / 30 10 40 30 50
Apalachicola 89 76 88 76 88 / 30 10 30 20 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Wool
SHORT TERM...Navarro/Harrigan
LONG TERM...Gould
AVIATION...Wool
MARINE...Navarro/Harrigan
FIRE WEATHER...Wool
HYDROLOGY...Harrigan
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
404 AM EDT MON JUL 29 2013
.SHORT TERM /TODAY THROUGH TUESDAY/...
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
&&
.PREV DISCUSSION... /ISSUED 152 AM EDT MON JUL 29 2013/
AVIATION...
06Z UPDATE...
A FEW SHOWERS ACROSS THE AREA BUT VERY ISOLATED IN NATURE AND
SHORT LIVED. ALTHOUGH A SHOWER IS POSSIBLE THIS MORNING NEAR A TAF
SITE...CHANCES ARE VERY LOW. SOME UNCERTAINTY IN THE CIG AND VSBY
FORECAST AGAIN THIS MORNING. STARTING TO SEE SCT040 IN THE ATL
AREA AND IT IS POSSIBLE THAT SOME LOWER CLOUDS OF 020-025 COULD
DEVELOP ACROSS THE AREA BY LATER THIS MORNING. IFR TO MVFR FOG IS
EXPECTED THIS MORNING...BUT THAT SHOULD BE MAINLY LIMITED TO MCN
AND AHN...WITH A POSSIBILITY OF MVFR AT FTY AND PDK.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON CIGS AND VSBYS. HIGH CONFIDENCE ON WINDS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 69 / 20 5 20 20
ATLANTA 87 67 88 70 / 10 5 10 20
BLAIRSVILLE 82 60 84 64 / 5 5 20 30
CARTERSVILLE 85 61 90 67 / 5 5 10 30
COLUMBUS 91 70 93 72 / 20 5 20 20
GAINESVILLE 87 67 86 70 / 5 5 20 30
MACON 91 67 92 69 / 20 10 20 20
ROME 88 61 91 67 / 5 5 10 30
PEACHTREE CITY 87 62 88 65 / 10 5 20 20
VIDALIA 92 73 90 72 / 30 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
152 AM EDT MON JUL 29 2013
.PREV DISCUSSION...
UPDATE...
/ISSUED 1041 PM EDT SUN JUL 28 2013/
ONLY A FEW SHOWERS REMAIN FROM AHN TO CORDELE AND THESE ARE ON THE
DYING TREND. BY 06Z IT SHOULD BE DRY ACROSS THE CWA. MADE MINOR
ADJUSTMENTS TO THE POPS. NO OTHER CHANGES PLANNED.
SHORT TERM /TONIGHT THROUGH MONDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
WEAK FRONTAL BOUNDARY DRAPED ACROSS THE CENTRAL CWFA THIS AFTERNOON.
LOW PRESSURE AND A WARM FRONT ARE SITUATED ACROSS THE FLORIDA
PANHANDLE. ISO/SCT CONVECTION HAS DEVELOPED AHEAD OF THE WAVE OF LOW
PRESSURE DOWN SOUTH. THIS ACTIVITY SHOULD AFFECT MAINLY AREAS ALONG
THE SOUTHERN CWFA BORDER. ISOLD SHRA HAVE DEVELOPED ACROSS NORTHEAST
GA IN THE HIGHER TERRAIN. WILL HAVE TO WATCH THE SHRA/TSRA IN THE SW
CORNER OF THE CWFA...MAY HAVE TO UP THE POPS TO LIKELY IF THE
ACTIVITY KEEPS SPREADING.
LATEST RUN OF THE HRRR DOESN`T DO MUCH WITH THE CONVECTION UP
NORTH...BUT KEEPS THE SOUTHERN ACTIVITY GOING UNTIL AROUND SUNSET.
THE POTENTIAL FOR SEVERE REMAINS LOW...BUT ANY THUNDERSTORM THAT
DEVELOPS WILL HAVE THE POTENTIAL TO PRODUCE LIGHTNING STRIKES AND
GUSTY WINDS.
HRRR DIMINISHES CONVECTION AFTER SUNSET AND KEEPS THE NIGHTTIME
MOSTLY DRY. SOME PATCHY FOG IS POSSIBLE...WITH THE SATURATED GROUND
AND COOLER OVERNIGHT LOWS.
WEAK...MOSTLY DIFFUSE...FRONTAL BOUNDARY REMAINS ACROSS THE SOUTHERN
CWFA TOMORROW. DRIER AIR DOES SETTLE ON THE NORTHERN SIDE OF THE
BOUNDARY. HOWEVER...SLIGHTLY HIGHER DEWPOINTS WILL REMAIN ACROSS THE
SOUTH. MOISTURE WILL CONTINUE TO POOL ALONG THE WEAK BOUNDARY...BUT
WITH WEAK FORCING AND MARGINAL INSTABILITY...CONVECTION IS EXPECTED
TO BE LIMITED AGAIN TOMORROW.
NLISTEMAA
LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
ADDED SLIGHT CHANCE POPS IN PORTIONS OF THE NORTH TUESDAY DUE TO
OROGRAPHIC ENHANCEMENT WITH RELATIVELY LIGHT WINDS WITH ANY LOW
LEVEL MOISTURE. HAVE MADE OTHER MINOR ADJUSTMENTS TO TEMPS BASED
ON LATEST BLEND OF GUIDANCE...OTHERWISE FORECAST LOOKS TO BE ON
TRACK AND PREVIOUS DISCUSSION FOLLOWS...
BAKER
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 359 AM EDT SUN JUL 28 2013/
LARGE SCALE PATTERN NOT FCST TO CHANGE MUCH DURING THE LONG TERM
PERIOD. UNUSUALLY ACTIVE WESTERLIES ACROSS THE CONUS WITH LONG
WAVE TROUGHING OVER THE EAST WILL CONTINUE. AFTER A BRIEF DRY
PERIOD WITH RISING HEIGHTS IN THE MID LEVELS...APPEARS THAT
WESTERLIES WILL DROP BACK DOWN INTO THE SE BY WED MORNING
CONTINUING THRU AT LEAST THUR NIGHT. BACK TO THE RAIN WE GO. BEST
CHC APPEARS TO BE WED AFT THRU THURS AFT. HEIGHTS PROGGED TO RISE
AGAIN ON FRI BUT THE WESTERLIES WILL BE JUST TO OUR NORTH.
GFS/ECMWF SHOW A COLD FRONT JUST TO OUR NORTH IN TN. MOISTURE FROM
REMNANTS OF DORIAN ALSO PROGGED BY LATE FRI AND SAT TO PUSH NORTH
INTO THE EASTERN GULF AND NRN FL AND MUCH OF GA.
ALL THIS SAID...NOT SEEING ANY SIGN OF SIGNIFICANT HEAVY RAIN OR SVR
WX. PW VALUES HIGH BUT NOT ANYTHING UNUSUALLY HIGH FOR THIS TIME OF
YEAR WITH VALUES AROUND 1.5 IN TUE/WED INCREASING TO 1.5-2.0 IN
THUR/FRI/SAT. SFC DEWPOINTS GREATER THAN 70 AND MLCAPE GREATER THAN
800 J/KG FCST TO REMAIN CONFINED TO SE COUNTIES THRU THURS THEN
SPREADING AREA WIDE FRI. COULD SEE SIGNIFICANT INSTABILITY BY NEXT
WEEKEND BASED ON 00Z GFS.
SNELSON
&&
.AVIATION...
06Z UPDATE...
A FEW SHOWERS ACROSS THE AREA BUT VERY ISOLATED IN NATURE AND
SHORT LIVED. ALTHOUGH A SHOWER IS POSSIBLE THIS MORNING NEAR A TAF
SITE...CHANCES ARE VERY LOW. SOME UNCERTAINTY IN THE CIG AND VSBY
FORECAST AGAIN THIS MORNING. STARTING TO SEE SCT040 IN THE ATL
AREA AND IT IS POSSIBLE THAT SOME LOWER CLOUDS OF 020-025 COULD
DEVELOP ACROSS THE AREA BY LATER THIS MORNING. IFR TO MVFR FOG IS
EXPECTED THIS MORNING...BUT THAT SHOULD BE MAINLY LIMITED TO MCN
AND AHN...WITH A POSSIBILITY OF MVFR AT FTY AND PDK.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON CIGS AND VSBYS. HIGH CONFIDENCE ON WINDS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 68 90 69 / 20 5 20 20
ATLANTA 87 68 88 70 / 10 5 10 20
BLAIRSVILLE 82 61 84 63 / 5 5 20 30
CARTERSVILLE 87 61 89 67 / 5 5 10 20
COLUMBUS 92 72 92 72 / 20 5 20 20
GAINESVILLE 87 68 86 69 / 5 5 20 20
MACON 91 69 91 69 / 20 10 20 20
ROME 87 61 89 68 / 5 5 10 30
PEACHTREE CITY 88 62 89 65 / 10 5 20 20
VIDALIA 91 73 90 73 / 20 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1050 PM MDT Sun Jul 28 2013
UPDATED AVIATION SECTION
.DISCUSSION...
An update for minor changes to the forecast. After a fairly active
evening with strong to severe thunderstorms over north central
and central Montana, the storms have quieted down. A storm with
heavy rain persists over the hi- line near Cut Bank, otherwise
lighter showers and some thunderstorms exist over central and
southwest Montana. A surge of moisture is expected to drop south
from Alberta overnight. Along with a weak upper level disturbance,
additional precipitation is expected - mainly over the hi-line. The
HRRR and RUC do indicate nocturnal precipitation/thunderstorms. As
a result, have bumped the pops over north central Montana
overnight. Other than this, the wind forecast was tweaked in the
period before midnight. Otherwise, no changes to the forecast. db
&&
.AVIATION...
UPDATED 0450Z.
The airmass remains somewhat unstable and showers and thunderstorms
continue to develop. Convective activity should continue overnight
as a weak cold front pushes south out of Canada and will bring an
influx of moisture with it. Areas of low clouds and rain may develop
behind the front, mainly across the Hi-Line. VFR conditions prevail
with MVFR conditions in the vicinity of thunderstorms. Increasing
MVFR conditions are possible after 08z associated with rain showers.
&&
.PREV DISCUSSION...
/ISSUED 550 PM MDT Sun Jul 28 2013/
Tonight through Tuesday...Not much change in the weather can be
expected in the short term period. An upper level low over Central
Alberta/Saskatchewan will remain quasi-stationary through Monday
night before an upper ridge builds over the Pacific Northwest and
Northern Rockies causing the low to accelerate east. Montana will
remain under a generally moist and somewhat unstable southwest to
westerly flow aloft through the short term for scattered showers
and thunderstorms each day. At this time there is nothing to
indicate that storms will become severe but they will become
increasingly moist as precipitable water levels increase across
the region and could bring locally heavy rain and possible
flooding concerns. Temperatures will remain near seasonable levels
each day. mpj
Tuesday Night through Sunday...Medium range forecast models
generally agree on the overall solution through most of the
period, only slightly disagreeing for the upcoming weekend. A weak
upper level ridge of high pressure will remain centered over
western Montana Tuesday night. However, weak disturbances moving
through the ridge will generally keep a slight chance of showers
and thunderstorms over the area. An upper level low pressure area
over the Pacific Northwest coast will then gradually move onshore
and across the Pacific Northwest Wednesday through Friday,
shifting the flow aloft to a more moist and unstable southwesterly
one. Disturbances ejecting from the upper low will move through
the flow and over the area, which the models reflect in higher
precipitation amounts over the area. Have therefore increased the
chances for precipitation during this period, especially so in the
mountains and over the plains of north central/central Montana.
This is due to the fact that the models tend to keep winds
easterly over the plains as surface high pressure remains east of
the area. These easterly winds will advect surface moisture into
the plains areas and move the moisture up the slopes of the Rocky
Mountain Front, making for efficient generation of precipitation.
The unstable flow aloft will also keep at least a slight chance of
thunderstorms around as well through the period, but the increased
chance of wet thunderstorms will help limit new fire starts due to
lightning strikes. Temperatures on Wednesday will warm to a few
degrees below seasonal averages, but the disturbances and
resulting precipitation will help keep high temperatures 5 to 10
degrees below average for this period. The high pressure ridge
will then rebuild into the state from the south for the weekend,
causing the upper low to retrograde back towards the Pacific
Northwest coast. This will decrease the chance of precipitation
and allow temperatures to warm back closer to normal by Sunday.
The only discrepancy is that the ECMWF model is a bit faster than
the GFS/GEM models in rebuilding this ridge, which would mean a
bit quicker of a warm up. Will monitor this situation over the
next few days and make adjustments accordingly. Coulston
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 50 74 51 78 / 40 30 20 20
CTB 48 68 47 72 / 40 20 20 20
HLN 54 79 53 83 / 30 20 10 30
BZN 48 80 48 83 / 30 30 20 20
WEY 36 74 38 74 / 30 20 20 20
DLN 47 81 47 83 / 20 10 10 20
HVR 52 73 51 74 / 40 30 30 30
LWT 51 71 50 75 / 50 50 30 40
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
402 AM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 29 2013
TODAY...MULTIPLE MODES OF ATMOSPHERIC UNREST ARE OPERATING ACROSS
THE FCST AREA THIS MORNING AND ARE EXPECTED TO CONTINUE THROUGH
THIS EVENING. STRATUS...FOG...DRIZZLE...SHOWERS PRODUCING DECENT
RAINFALL IN A WARM CLOUD PROCESS ARE OPERATING ACROSS SWRN NEB
THROUGH NCNTL NEBRASKA THIS MORNING. THIS AREA OF WEATHER IS
EXPECTED TO SHIFT EAST THIS MORNING AND COVER AREAS ALONG AND
EAST OF HIGHWAY 183 THIS AFTERNOON. IT IS BELIEVED THAT THE
SHOWERS AND DRIZZLE/FOG SHOULD EXIT BY 18Z AS THIS IS BEING
DRIVEN BY MOISTURE TRANSPORT AT THE 315K SFC AND ACCORDING TO THE
RAP...THIS TRANSPORT SHOULD WEAKEN THIS MORNING.
THE ONGOING MCS ACROSS NWRN NEB IS EXPECTED TO DECAY BY 12Z AS
RADAR SUGGESTS AN OCCLUSION PROCESS IS UNDERWAY ACROSS FAR SWRN
SD. ALSO THE RAP SHOWS MOISTURE TRANSPORT ON THE 315K SFC WILL
WEAKEN.
TEMPERATURES TODAY RANGE FROM 60S ACROSS THE EAST UNDER A BLANKET
OF STRATUS TO 80S ACROSS WRN NEB WHERE IT IS BELIEVED SKIES WILL
CLEAR. THE RAP MODEL SHOWS 750MB CAPE INCREASING TO AROUND 1000
J/KG AND THE NAM THEN SHOWS THE ATM DESTABILIZING ACROSS SWRN AND
WRN NEB LATE THIS AFTERNOON. DOWN DRAFT CAPE NEAR 1000 J/KG COULD
SUPPORT A FEW STORMS WITH GUSTY WINDS...MAINLY THIS EVENING AS
THE STORMS ARE EXPECTED TO ORIGINATE ACROSS THE CYS DIVIDE AND
PARTS OF NERN COLO AND MOVE INTO THE FCST LATE THIS AFTN OR EARLY
EVENING.
TONIGHT...SCATTERED TSTMS ARE EXPECTED TO REMAIN WEST OF HIGHWAY
83 AND MAINLY ALONG AND WEST OF HIGHWAY 61. THE NAM SHOWS THESE
STORMS WEAKENING/DISSIPATING BY 03Z. A WEAK MOSTLY OUTFLOW DRIVEN
COLD FRONT IS EXPECTED TO DRAPE FROM KOGA TO KVTN IN THE WAKE OF
THE STORMS AND LOW LEVEL MOISTURE EAST OF THE FRONT APPEARS
LIKELY TO PRODUCE ANOTHER ROUND OF STRATUS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 29 2013
UPPER LEVEL RIDGE IS GENERALLY ACROSS THE 4 CORNERS REGION...AND
WILL BUILD EAST TOWARDS THE WEEKEND. MEANWHILE AN UPPER LEVEL
TROUGH/LOW WILL PUSH ACROSS CANADA MID WEEK...WITH THE LOW
REACHING THE SRN PART OF HUDSON BAY BY THE WEEKEND. OVER THE HIGH
PLAINS FLOW WILL BE NORTHWEST THROUGH THE WEEK...WITH A TRANSITION
TO MORE ZONAL BY WEEKEND.
AT THE SFC..COOL CANADIAN HIGH PRESSURE ACROSS THE CENTRAL PLAINS
EARLY...WILL SLOWLY PUSH EAST...WITH A WARM UP EXPECTED. THEN A
COLD FRONT WILL PUSH ACROSS THE AREA WEDNESDAY WITH ANOTHER COOL
DOWN TO END THE WEEK. HIGHS SHOULD RETURN TO THE 80S...NEAR OR
SLIGHTLY BELOW SEASONAL BY MID WEEK...AHEAD OF THE FRONT. BY FRIDAY
AS THE COOLER HIGH PRESSURE PUSHES ACROSS THE CENTRAL
PLAINS...TEMPS TO COOL BACK INTO THE UPPER 70S TO LOWER 80S. AFTER
THE EXTENT OF THE LATEST COOL DOWN...WILL HAVE TO MONITOR CLOSELY
THE COOLER AIR AS A TREND DOWN IN TEMPS IS POSSIBLE.
MODELS IN AGREEMENT WITH AN ACTIVE PATTERN TO CONTINUE THROUGH THE
WEEK WITH SEVERAL DISTURBANCES TO RIDE THE PERIPHERY OF THE RIDGE
AND ACROSS THE AREA. MOISTURE REMAINS DECENT WITH DEW PTS IN THE
UPPER 50S TO LOWER AND MID 60S. WITH EACH QUICK MOVING WAVE EXPECT
SHOWERS AND A FEW THUNDERSTORMS TO BE POSSIBLE.
ON WEDNESDAY...WITH THE PASSAGE OF THE COLD FRONT AND COOLER AIR
ALOFT...THERE COULD BE A FEW STRONG THUNDERSTORMS. TIMING AND
PLACEMENT OF THE BEST INSTABILITY STILL IN QUESTION...AND WILL BE
WATCH OVER THE NEXT COUPLE OF DAYS. THE REST OF THE WEEK WILL
CONTINUE TO SEE A CHANCE FOR SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH EACH PASSING WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1223 AM CDT MON JUL 29 2013
CEILINGS BELOW 1000 FEET AGL ARE LIKELY TO CONTINUE THROUGH THE
NIGHT TONIGHT IN CENTRAL AND SOUTHWEST NEBRASKA...EVEN SPREADING
INTO A LARGE PART OF NORTH CENTRAL NEBRASKA BY 08Z. SOME
PROBABILISTIC MODEL OUTPUT HAS THE CEILING LIFTING ABOVE 1000
FEET BY 17Z...BUT CONTINUING LESS THAN 2000 FEET UNTIL MID-
AFTERNOON. THAT ASSESSMENT SEEMS TO APPLY TO THE LBF TERMINAL.
FOR VTN...THERE IS MORE UNCERTAINTY REGARDING THE EXPECTATION OF
CEILINGS BELOW 1000 FEET. FOR THE AREAS WITH CEILING LOWER THAN
1000 FEET...IT IS NOT LIKELY TO GO BELOW 300 FEET AND WILL MOST
LIKELY STAY AT 600 FEET OR HIGHER IN MUCH OF THE AREA. AREAS OF
BR/FG MAY DEVELOP ALONG THE EDGES OF THE STRATUS BRINGING
VISIBILITY TO LESS THAN 1SM IN AREAS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1149 PM CDT SUN JUL 28 2013
.UPDATE...
SEE 06Z AVIATION FORECAST BELOW.
&&
.AVIATION...
VFR CONDITIONS SHOULD PREVAIL THROUGH ABOUT SUNRISE ACROSS WEST
CENTRAL TEXAS. MODELS CONTINUE TO SHOW SOME MVFR CIGS DEVELOPING
ACROSS THE SOUTHERN AND EASTERN TERMINALS BY AROUND SUNRISE. IF IT
DOES DEVELOP...SHOULD ONLY LAST A FEW HOURS BEFORE LIFTING AND DISSIPATING.
OTHERWISE...SOUTH AND SOUTHEAST WINDS WILL PREVAIL
TONIGHT...BEFORE INCREASING AND BECOMING GUSTY BY MID MORNING.
&&
.PREV DISCUSSION... /ISSUED 1052 PM CDT SUN JUL 28 2013/
UPDATE...
MINOR CHANGES MADE TO THE FORECAST FOR THE REST OF THE NIGHT.
ISOLATED CONVECTION CONTINUES ACROSS PORTIONS OF THE CONCHO VALLEY
AND NORTH EDWARDS PLATEAU LATE THIS EVENING. WILL KEEP SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORM`S GOING OVERNIGHT FOR ROUGHLY
THE WESTERN HALF OF THE CWA AS A WEAK MID LEVEL DISTURBANCE
AFFECTS THE AREA. LATEST RUC SEEMS TOO AGGRESSIVE WITH QPF
OVERNIGHT WHILE THE HRRR SEEMS MORE REASONABLE. ONLY MINOR CHANGES
WERE MADE TO TEMPS AND DEWPOINTS TO ACCOUNT FOR TRENDS. UPDATED
PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 621 PM CDT SUN JUL 28 2013/
UPDATE...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
AREA RADARS SHOW A FEW SHOWERS ACROSS THE NORTHWEST HILL COUNTRY
AND NORTHERN EDWARDS PLATEAU...BUT NOTHING THAT SEEMS TO BE
IMMINENT FOR THE TERMINAL LOCATIONS AT KJCT/JUNCTION...KBBD/BRADY...AND
KSOA/SONORA. COVERAGE IS ISOLATED AT BEST...BUT SHOULD CONTINUE
FOR AT LEAST THE NEXT FEW HOURS. HAVE INCLUDED A VCSH FOR THE
THOSE SITES AND WILL CONTINUE TO MONITOR. IF THOSE AREAS DO SEE A
SHOWER...THEN GUSTY WINDS AND BRIEF MVFR CIGS WILL BE POSSIBLE.
OTHERWISE...VFR CONDITIONS SHOULD PREVAIL. MODELS SUGGEST SOME
THREAT OF MVFR CIGS AS LOW CLOUDS DEVELOP ACROSS THE SOUTHERN AND
EASTERN AREA BY SUNRISE...AND WILL CONTINUE THE MENTION IN THE
FORECAST FOR NOW.
PREV DISCUSSION... /ISSUED 403 PM CDT SUN JUL 28 2013/
SHORT TERM...
/TONIGHT/
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MOST COUNTIES...
UPPER-LEVEL CIRCULATION...BASED ON THE LATEST WATER VAPOR
LOOP...DOES NOT LOOK AS PROMISING FOR POSSIBLE SHOWERS AND
THUNDERSTORMS TONIGHT. THE NAM AND GFS 500 MB WIND FIELDS INDICATE
A MINOR SHORT-WAVE TROUGH IN THE FLOW OVER SOUTHEASTERN NEW MEXICO
AND WEST TEXAS. THE NAM DEVELOPS THIS TROUGH MORE THAN THE GFS.
UNFORTUNATELY...ANALYSIS OF THE WATER VAPOR LOOP DOES NOT REVEAL
ANY INDICATION OF THIS TROUGH. THE OVERALL FLOW IN THIS AREA IS
NORTHWEST TO SOUTHEAST. THE NAM REALLY DEVELOPS QPF OVER MUCH OF
WEST CENTRAL TEXAS TONIGHT...AND THE MET MOS PRODUCTS PRESENT 60
POPS FOR BOTH ABILENE AND SAN ANGELO TONIGHT. THE MEX HAS ONLY 10
POPS. SO...WITH LOW CONFIDENCE...I DECIDED TO CONTINUE ONLY 20
POPS FOR TONIGHT. BUT...I EXPANDED THE 20 POPS AREA OVER MORE OF
WEST CENTRAL TEXAS TO ALL EXCEPT MAINLY THE NORTHWEST HILL
COUNTRY.
/TOMORROW/
SLIGHT CHANCE POPS CONTINUES MOST LOCATIONS...
THE NAM CONTINUES AN UPPER-LEVEL TROUGH OVER WEST CENTRAL TEXAS
INTO TOMORROW. AGAIN...MY CONFIDENCE IS NOT HIGH. AT LEAST...IT IS
NOT HIGH ENOUGH TO GIVE ABILENE 50 POPS FOR TOMORROW AS THE MET
MOS PRODUCT INDICATES. SO...I WILL CONTINUE WITH ONLY SLIGHT
CHANCE POPS OVER AN ALMOST IDENTICAL AREA TO TONIGHT.
OTHERWISE...AFTERNOON HIGHS TOMORROW IN THE RANGE OF 98 TO AROUND
100...MOST LOCATIONS...LOOK GOOD.
/MONDAY NIGHT/
SLIGHT CHANCE EVENING POPS MAINLY WEST...
IF SHOWERS AND THUNDERSTORMS DO DEVELOP TOMORROW...SOME MAY LINGER
ACROSS MAINLY OUR WEST COUNTIES TOMORROW EVENING. THUS...I DECIDED
TO CONTINUE 20 POPS FOR SOME OF OUR BIG COUNTRY COUNTIES AND A FEW
OTHER WESTERN COUNTIES. OTHERWISE...RAIN CHANCES END AND
TEMPERATURES DROP TO AROUND 75 FOR OVERNIGHT LOWS.
/TUESDAY THROUGH WEDNESDAY.
DRY AND HOT...
MODELS STRENGTHEN THE RIDGE OVER THE REGION. CLOUD COVER WILL
DIMINISH. AFTERNOON HIGHS AND OVERNIGHT LOWS AROUND 100 AND
75...RESPECTIVELY...LOOK LIKELY.
LONG TERM...
/WEDNESDAY NIGHT THROUGH SUNDAY/
DRY CONDITIONS CONTINUE WITH UNSEASONABLY HOT AFTERNOON HIGHS...
MODELS THIS CYCLE CONTINUE HIGH PRESSURE OVER THE REGION. MODELS
INDICATE THE 500 MB HIGH PRESSURE CENTER WILL MEANDER OVER OR NEAR
TEXAS THROUGH NEXT WEEKEND. AFTERNOON HIGHS MAINLY IN THE UPPER
90S TO AROUND 100...WHICH WE ALREADY IN OUR PREVIOUS FORECAST
PACKAGE...STILL LOOKS GOOD. OVERNIGHT LOWS MAY VARY A DEGREE OR
TWO. HOWEVER...NUMBERS CLOSE TO PERSISTENCE...MAINLY LOWER TO MID
70S...LOOK REASONABLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 75 98 76 99 76 / 20 20 5 5 0
SAN ANGELO 75 98 75 100 75 / 20 20 5 5 0
JUNCTION 75 97 75 98 74 / 10 10 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1146 PM CDT SUN JUL 28 2013
.AVIATION...
FOR THE 06Z TAFS...NO SIGNIFICANT CHANGES FROM THE 00Z TAFS.
LATE EVENING INFRARED SATELLITE IMAGERY HAS NOT INDICATED A
SIGNIFICANT INCREASE IN MID-LEVEL CLOUDS/MOISTURE RETURN OVER THE
REGION...SO CONFIDENCE IN THE RAP FORECAST SOLUTION MENTIONED
BELOW HAS INCREASED. IN GENERAL...AN ISOLATED SHOWER OR
THUNDERSTORM IS NOT IMPOSSIBLE OVERNIGHT...BUT CHANCES LOOK SMALL
AT THIS TIME. MVFR CIGS ARE STILL EXPECTED TO BUILD OVER KACT
AROUND 12Z.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
FOR THE 00Z TAFS...VFR CONDITIONS ARE EXPECTED AT METROPLEX AREA
TAF SITES WHILE HIGH MVFR CIGS ARE EXPECTED OVER KACT EARLY
TOMORROW MORNING. THERE ARE ALSO SOME LOW PRECIPITATION CHANCES
WORTH MENTIONING HERE IN THE DISCUSSION...BUT NOT IN THE TAFS AT
THIS TIME.
EVENING OBJECTIVE SURFACE ANALYSIS DEPICTS A TROUGH OF LOW-
PRESSURE ORIENTED EAST-WEST ACROSS CENTRAL TEXAS...JUST SOUTH OF
TEMPLE. ANALYSIS ALSO DEPICTS A RELATIVELY TIGHT GRADIENT OF
THETA-E ALONG THIS TROUGH WITH HIGHER THETA-E VALUES LOCATED TO
THE SOUTH OF THE TROUGH. THIS TROUGH LIKELY MARKS WHAT IS LEFT OF
THE STATIONARY BOUNDARY THAT WAS LOCATED NEAR THE TX COAST
YESTERDAY EVENING.
MODELS INDICATE THAT THIS TROUGH AND HIGHER THETA-E AIR WILL MOVE
NORTH OVERNIGHT KEEPING SOME LOW CHANCE OF ISOLATED RAIN SHOWERS
IN PLAY THROUGH THE OVERNIGHT HOURS FOR ALL AREA TAF SITES. NAM
FORECAST SOUNDINGS SEEM TO BE THE MOST AGGRESSIVE WITH MOISTURE
INCREASE AND ASCENT ASSOCIATED WITH THIS NORTHWARD MOVING BOUNDARY
INDICATING SOME CHANCE AT ELEVATED THUNDERSTORMS TONIGHT. THE RAP
SOUNDINGS ARE DRIER AND PROBABLY MORE REPRESENTATIVE OF THIS WEAK
BOUNDARY THAN THE NAM. THEREFORE KEPT MENTION OF PRECIPITATION
OUT OF THE TAFS FOR THE TIME BEING.
MODELS INDICATE THAT THE BOUNDARY BECOMES SO DIFFUSE THAT IT IS
DIFFICULT TO TRACK ANY MORE BY TOMORROW MORNING. THIS SEEMS
REASONABLE WITH NO CONVERGENCE OR LARGE SCALE FLOW TO REINFORCE
THE FRONTAL BOUNDARY. ATTENTION WILL THEN TURN TO AREAS NORTHWEST
OF THE METROPLEX TOMORROW AFTERNOON AS A WEAK UPPER LEVEL
DISTURBANCE MOVES OVERHEAD. AT THIS TIME THE MAIN AREA OF FORCING
FOR ASCENT LOOKS TO REMAIN NORTHWEST OF THE METROPLEX...SO THINK
ALL THUNDERSTORM ACTIVITY WILL TEND TO FOLLOW SUIT.
CAVANAUGH
&&
.UPDATE...
UPDATING FORECAST TO REMOVE POPS FOR THE REST OF THE NIGHT. FWD
SOUNDING SHOWS INVERSION SETTING UP ALREADY...AND IT WILL BE
STRONGER AS THE EVENING COOLS. ALSO TWEAKING SKY/TEMPERATURE GRIDS
JUST A BIT. 84
&&
.PREV DISCUSSION... /ISSUED 310 PM CDT SUN JUL 28 2013/
THE FRONT THAT MOVED THROUGH FRIDAY NIGHT HAS LOST MOST OF ITS
DEFINITION DURING ITS STINT IN CENTRAL TEXAS...BUT THE BROAD AREA
OF ENHANCED MOISTURE THAT POOLED ALONG THE BOUNDARY IS NOW SURGING
NORTHWARD ACROSS NORTH TEXAS. INSTABILITY AND LIFT IS LIMITED...
BUT THE LOW-MID 70 DEWPOINTS COMBINED WITH DIURNAL HEATING HAVE
RESULTED IN A FEW CONVECTIVE SHOWERS IN CENTRAL AND SOUTHEAST
TEXAS. ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS EVENING ACROSS
THE SOUTHERN HALF OF THE CWA WHERE THERE WILL BE A LITTLE BETTER
INSTABILITY...BUT WILL JUST MENTION ISOLATED SHOWERS OVER THE
NORTHERN HALF OF THE AREA THIS EVENING AND TONIGHT. LOWS TONIGHT
WILL BE SEVERAL DEGREES WARMER THAN LAST NIGHT THANKS TO THE
INCREASED MOISTURE...CLOUD COVER AND SOUTHERLY WINDS.
MODELS HAVE ANALYZED A WEAK POCKET OF POTENTIAL VORTICITY OVER
WEST TEXAS AND GUIDANCE /WITH THE EXCEPTION OF THE GFS/ IS IN GOOD
AGREEMENT THAT THIS ENERGY WILL TRACK NORTHEASTWARD AND ACROSS
THE NORTHWEST ZONES TOMORROW. MOISTURE/INSTABILITY WILL BE
SUFFICIENT FOR A FEW SHOWERS/STORMS IN THE NW ZONES MONDAY...AND
ACROSS THE RED RIVER COUNTIES MONDAY EVENING BEFORE THE ENERGY
EXITS THE REGION. THE BRUNT OF THE CONVECTION WILL REMAIN WELL TO
THE NORTH OF THE REGION ACROSS KANSAS AND OKLAHOMA WHERE A STRONG
SHORTWAVE TROUGH WILL TRACK THROUGH THE PLAINS. THIS SHORTWAVE
WILL BE RESPONSIBLE FOR INCREASED SOUTHERLY FLOW TOMORROW WITH
WINDS NEAR 15-20 MPH DURING THE AFTERNOON. HIGH TEMPS WILL
CONTINUE THEIR MODERATING TREND WITH READINGS JUST SHY OF NORMAL.
THE UPPER LEVEL RIDGE WILL STRENGTHEN OVER NEW MEXICO BY TUESDAY
AND WEDNESDAY...WHICH RESULTS IN NORTHWEST TO NORTHERLY FLOW ALOFT
OVER NORTH TEXAS. THIS SHOULD HELP PROPEL A WEAK FRONT IN OKLAHOMA
SOUTHWARD TO THE RED RIVER VALLEY BY WEDNESDAY. MOISTURE AND
INSTABILITY LOOK SUFFICIENT FOR A SLIGHT CHANCE OF SHOWERS/STORMS
ACROSS THE NORTHERN COUNTIES WEDNESDAY AFTERNOON AND EVENING.
AGAIN THE GFS IS THE OUTLIER SOLUTION AND KEEPS THE FRONT WELL TO
THE NORTH...BUT THE GEM/ECMWF REMAIN CONSISTENT IN BRINGING THE
FRONT INTO TEXAS. THE ECMWF IS NOW PUSHING THE FRONT WELL INTO THE
HEART OF THE CWA ON THURSDAY BEFORE DISSIPATING IT. WILL SHOW 10
PERCENT POPS OVER THE ENTIRE AREA ON THURSDAY FOR STRAY CONVECTION
ALONG THE OLD FRONTAL BOUNDARY...BUT WILL NOT MENTION IT IN THE
WORDED FORECAST JUST YET AS THE UPPER HIGH WILL BE INTENSIFYING ON
THURSDAY AND MAY SUPPRESS CONVECTION ALTOGETHER. ALTHOUGH THE
FRONT LOOKS TO ENTER THE CWA MIDWEEK...THERE WILL BE LITTLE COOL
ADVECTION ASSOCIATED WITH IT. IN FACT DIMINISHING SURFACE WINDS
WILL RESULT IN HIGH TEMPS WARMING A DEGREE OR TWO EACH DAY...AND
THE HUMIDITY MAY BE A BIT OPPRESSIVE THURSDAY DUE DEEPER MOISTURE
POOLING ALONG THE DISSIPATING FRONT.
THE UPPER LEVEL RIDGE WILL STRENGTHEN BY LATE WEEK AND TEMPS WILL
CONTINUE TO WARM. FRIDAY LOOKS TO BE THE WARMEST DAY WITH HIGHS
NEAR 100+ IN MOST AREAS. THE CENTER OF THE RIDGE WILL BACK OFF TO
THE SOUTHWEST NEXT WEEKEND WITH PERHAPS A 1-2 DEGREE COOL DOWN.
THE GOOD NEWS IS THAT ANOTHER STRONG BACKDOOR FRONT IS STILL
ADVERTISED IN ABOUT 8 DAYS. THIS LOOKS TO BE THE NEXT SHOT AT MORE
SCATTERED RAINFALL AND COOLER TEMPS.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 96 76 97 77 / 10 10 5 5 5
WACO, TX 76 96 76 97 76 / 10 5 5 5 5
PARIS, TX 71 93 72 95 73 / 10 10 20 10 10
DENTON, TX 75 95 75 96 75 / 10 20 10 10 10
MCKINNEY, TX 74 94 74 96 75 / 10 10 10 10 10
DALLAS, TX 78 96 77 98 79 / 10 10 5 5 5
TERRELL, TX 75 95 74 96 75 / 10 5 5 5 5
CORSICANA, TX 75 96 74 96 75 / 10 5 5 5 5
TEMPLE, TX 75 96 74 97 74 / 10 5 5 5 5
MINERAL WELLS, TX 73 96 73 98 75 / 10 20 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
433 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM EASTERN NEW YORK TO CENTRAL GEORGIA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND WILL REMAIN
ACROSS THE MID ATLANTIC INTO TUESDAY. LOW PRESSURE COMING OUT OF
THE CENTRAL PLAINS WILL APPROACH THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT MONDAY...
MSAS LIFTED INDEX ANALYSIS AND SURFACE PRESSURE FROM 07Z/3AM
SHOWED COLD FRONT FROM JUST EAST OF LYNCHBURG TO JUST SOUTH OF
MARTINSVILLE. ISOLATED SHOWERS WERE JUST EAST OF THE FRONT WITH A
SUBTLE SHORT WAVE COMING THROUGH THE BASE OF THE TROF HELPING
TRIGGER THE PRECIPITATION. LOCAL WRF AND 06Z RUC GUIDANCE LINED UP
WELL WITH THE CURRENT LOCATIONS OF THE PRECIPITATION. BOTH OF
THESE MODELS HAD ALL OF THE PRECIPITATION OUT OF THE FORECAST AREA
BY 10Z/6AM. CLOUDS IN THE EAST WILL TAKE LONGER TO EXIT THE
FORCAST AREA...BUT BY 15Z/11AM...MUCH OF THE REGION WILL BE
MOSTLY SUNNY. SURFACE DEW POINTS HAVE DROPPED INTO THE LOWER 50S
ACROSS WEST VIRGINIA. MODELS HAVE ALL DEW POINTS IN THE FORECAST
AREA DROPPING BELOW 60S DEGREES BY 21Z/5PM. A SLIGHT DOWNSLOPE
WIND WILL BRING THE DRIER AIR ALOFT DOWN TO THE SURFACE EAST OF
THE BLUE RIDGE THIS AFTERNOON. USED A BLEND OF MET/MAV GUIDANCE
FOR AFTERNOON HIGHS. VALLEYS WILL DECOUPLE TONIGHT SO FOLLOWED
COOLER NUMBERS THERE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
AN UPPER LEVEL LOW OVER THE GREAT LAKES THIS MORNING WILL TRAVEL
NORTHEAST INTO THE CANADIAN MARITIMES TUESDAY INTO WEDNESDAY. HIGH
PRESSURE WILL SLIDE EAST ACROSS OUR REGION TUESDAY AND PUSH INTO THE
ATLANTIC WEDNESDAY. COOLER AND DRIER WEATHER EXPECTED TUESDAY. BELOW
NORMAL HIGHS TEMPERATURES WILL RANGE FROM THE LOWER 70S IN THE
MOUNTAINS TO THE MID 80S IN THE PIEDMONT.
MOISTURE OVERRUNS THE RIDGE TUESDAY NIGHT WITH THE CHANCE FOR RAIN
TO RETURN IN THE SOUTHWESTERN PORTIONS OF FORECAST AREA. WITH
ADDITIONAL CLOUD COVER...PLAYED LOW TEMPERATURES CLOSER TO THE
WARMER MOS GUIDANCE TUESDAY NIGHT WITH READINGS THE MID 50S IN THE
MOUNTAINS TO UPPER 60S IN THE SOUTHEAST. LOW TEMPERATURES COULD BE
COOLER ESPECIALLY IN THE NORTHWEST MOUNTAINS IF CLOUD COVER OR
MOISTURE AND SHORTWAVE DOES NOT ARRIVAL OR IS SLOWER. GOOD CHANCE
OF RAIN WEDNESDAY AND WEDNESDAY NIGHT AS AN INSITU WEDGE TAKES
RESIDENCE OVER THE AREA. LEANING TOWARDS A NAM/ECMWF BLEND...RAIN
SHOULD SPREAD NORTHEAST ACROSS OUR REGION WEDNESDAY. THE BEST CHANCE
OF RAIN IS ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS WITH A
PERSISTENT SOUTHEAST FLOW. WITH THE RAIN KEPT THE ADVERTISED COOLER
HIGHS WEDNESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO LOWER 80S IN
THE PIEDMONT. ALLOWED FOR SOME THUNDERSTORMS IN WEST. USED THE
ENSEMBLE LOWS FOR WEDNESDAY NIGHT FROM THE LOWER 60S IN THE WEST TO
AROUND 70 DEGREES IN THE EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 AM EDT MONDAY...
STRATIFORM RAIN WILL GIVE WAY TO SHOWERS ON THURSDAY...AS A SURFACE
WAVE TRACKS NORTH ALONG A FRONT. THIS FRONT IS EXPECTED TO CLEAR THE
AREA THURSDAY EVENING. SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
WILL BRING DRY WEATHER BACK INTO THE REGION THURSDAY NIGHT INTO
SATURDAY. THEN THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
INCREASES ON SUNDAY WITH THE APPROACH OF ANOTHER COLD FRONT.
ON THURSDAY...AS A SURFACE WAVE TRACKS NORTH ALONG A FRONT. THIS
FRONT IS EXPECTED TO CLEAR THE AREA THURSDAY EVENING. SURFACE HIGH
PRESSURE AND ZONAL FLOW ALOFT WILL BRING DRY WEATHER BACK INTO THE
REGION THURSDAY NIGHT INTO SATURDAY. THEN THE NEXT CHANCE FOR
SHOWERS AND THUNDERSTORMS INCREASES ON SUNDAY WITH THE APPROACH OF
ANOTHER COLD FRONT.
TEMPERATURES SHOULD REBOUND TOWARD NORMAL ON THURSDAY AS THE RAIN
MOVES EAST. TEMPERATURES WILL BE AT OR ABOVE NORMAL NEXT WEEKEND
UNTIL THE FRONT PASSES TO THE EAST.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AS OF 130 AM EDT MONDAY...
A COLD FRONT WAS NEAR BLUE RIDGE. WIDELY SCT SHRA/TSRA WERE FOUND
MAINLY EAST OF THE FRONTAL BOUNDARY FROM THE VA/NC PIEDMONT
EASTWARD TO THE COAST. EXPECT DAN TO HAVE SHOWERS WITH OCCASIONAL
MVFR VISIBILITIES THROUGH 08Z/4AM.
HIGH POTENTIAL FOR IFR-LIFR FOG AT LWB AND BCB...AND MVFR FOG FOR
DAN AND LYH EARLY THIS MORNING. GROUND IS MOIST FROM RECENT RAIN
AND ALTHOUGH AIR MASS MOVING INTO THE AREA IS DRY...IMMEDIATE SFC
LAYER WILL REMAIN QUITE MOIST AND DECOUPLE FROM BOUNDARY LAYER.
THIS SHOULD ALLOW FOR A SHALLOW LAYER OF GROUND FOG TO FORM AT
THESE TYPICAL SITES. MODERATE CONFIDENCE OF HOW LOW VISIBILITIES
WILL BE. WITH LOWER SURFACE DEW POINTS COMING INTO THE
REGION...TEMPERATURE/DEW POINT SPREAD AT LYH AND DAN MAY NOT
SUPPORT FOG FOR LONG.
SOME STRATOCUMULUS WAS FORMING ALONG THE WESTERN WEDGE OF THE
APPALACHIANS. BLF MAY GO IN AND OUT OF MVFR CEILINGS EARLY THIS
MORNING. HIGHER CONFIDENCE THAT LWB WILL STAY VFR UNTIL THE GROUND
FOG FORMS.
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY...AND INFLUENCE
THE WEATHER PATTERN THROUGH TUESDAY. MAINLY VFR CONDITIONS ARE
EXPECTED THROUGH THIS TIME PERIOD WITH LATE NIGHT AND EARLY
MORNING VALLEY FOG AND IFR VISIBILITIES LIKELY.
ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA.
EXPECT A RETURN OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS AS EARLY AS LATE TUESDAY NIGHT ACROSS THE WEST.
FOR THURSDAY AND FRIDAY...AN UPPER RIDGE STRETCHES EAST WITH
MOUNTAIN THUNDERSTORMS EXPECTED DURING THE AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
710 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT MOVES ACROSS THE REGION TODAY...POSSIBLY TRIGGERING
AN ISOLATED SHOWER ESPECIALLY ACROSS EASTERN MASSACHUSETTS AND
RHODE ISLAND. HIGH PRESSURE BUILDS INTO THE NORTHEAST TONIGHT
THROUGH WED...DELIVERING DRY WEATHER TO THE AREA ALONG WITH
COMFORTABLE TEMPERATURES AND HUMIDITY. ANOTHER FRONTAL SYSTEM
APPROACHES NEW ENGLAND THU AND FRI WITH SHOWERS LIKELY. COOLER AND
MAINLY DRY WEATHER ARE THE LATEST TRENDS FOR NEXT WEEKEND
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE..
LOW CLOUDS AND FOG CONTINUE TO STREAM ACROSS THE AREA. EARLY
CONVECTION UPSTREAM ACROSS EASTERN PA/NJ AND THE LOWER HUDSON
VALLEY HAS COMPLETELY ERODED. UNFORTUNATELY NONE OF THE GUID
SIMULATED THIS VERY WELL...WITH MODELS PROJECTING CONVECTION
CONTINUING THIS MORNING. THIS INCLUDES THE HRRR. PERHAPS
CONVECTION WELL SOUTH OF NEW ENGLAND OVER THE OCEAN ROBBED THIS
AREA OF MOISTURE AND INSTABILITY. NONETHELESS COLD FRONT ENTERING
THE NYC AREA AND HUDSON VALLEY OF NY. DEW PTS STILL IN THE MU 60S
TO NEAR 70 ACROSS NEW ENGLAND AHEAD OF THE FRONT. MODELS SUGGEST
UP TO 1500 J/KG OF CAPE BY 18Z. WINDOW OF OPPORTUNITY FOR
CONVECTION WILL BE SMALL...AS DEEP LAYER DRY AIR ALOFT IS RACING
EASTWARD AND WILL LIMIT DEEP CONVECTION ACROSS NEW ENGLAND. THUS
BEST CHANCE FOR SHOWERS/TSTMS WILL BE 15Z-18Z AND ACROSS EASTERN
MA AND RI WHERE SEA BREEZE BOUNDARIES WILL ENHANCE LOW LEVEL
CONVERGENCE AND HELP MOISTEN THE COLUMN. NEVERTHELESS AREAL
COVERAGE SHOULD BE ISOLATED AND DIMINISH MID TO LATE AFTERNOON
FROM WEST TO EAST. GIVEN THESE LIMITING FACTORS WE LOWERED POPS
FROM CHANCE TO SLIGHT CHANCE. EARLIER DISCUSSION BELOW.
---------------------------------------------------------------
AREAS OF FOG HAVE DEVELOPED IN PORTIONS OF SOUTHERN NEW ENGLAND...IN
PARTICULAR EAST COASTAL MA. THE FOG WILL REDUCE VISIBILITY TO 1/2
MILE AT TIMES THROUGH 7 AM. THE FOG IS EXPECTED TO LIFT AND
DISSIPATE BY MID MORNING.
A COLD FRONT EXTENDING NORTH TO SOUTH THROUGH EASTERN NY AND NJ
IS EXPECTED TO PUSH INTO SOUTHERN NEW ENGLAND EARLY THIS MORNING.
MODELS INDICATE THAT THE SURFACE FRONT MAY TAKE THE ENTIRE DAY TO
PUSH THROUGH OUR AREA...POSSIBLY INTO THE EVENING ACROSS FAR
EASTERN ZONES. HOWEVER...PRONOUNCED MID LEVEL DRYING MOVES IN FROM
W TO E DURING THE LATE MORNING AND EARLY AFTERNOON ACROSS OUR
AREA. NAM AND RAP INDICATE PWATS FALL TO AROUND AN INCH BY 18Z IN
WESTERN HALF OF THE FORECAST AREA...GFS PUSHES IN DRIER AIR
QUICKER. WITH APPROACH OF FROPA AND SCATTERED LINGERING SHOWERS
ALONG AND AHEAD OF THE FRONT IT IS PRUDENT TO START OFF THE DAY
WITH CHANCE POPS. THEN WITH MODELS INTRODUCING SIGNIFICANT MID
LEVEL DRYING WILL GRADUALLY DROP OFF POPS FROM WEST TO EAST...WITH
ONLY A SLIGHT CHANCE POP E COASTAL MA AND VICINITY DURING EARLY-
MID AFTERNOON WITH THE ADDED POSSIBILITY THERE THAT SEA BREEZE
DEVELOPMENT COULD HELP TRIGGER SOME SHOWERS.
CONSIDERABLE CLOUDINESS TO START OFF THE DAY WITH A MIX OF STRATUS
AND CONVECTIVE DEBRIS CLOUDS...THEN GRADUAL DECREASE IN CLOUDS
EXPECTED FROM WEST TO EAST.
USING A BLEND OF MAV/MET GUIDANCE WITH MAX TEMPS IN THE LOW TO MID
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
MONDAY NIGHT...COLD FRONT MOVES OFFSHORE...WHILE HIGH PRESSURE
BUILDS OVER THE OHIO VALLEY. MOSTLY CLEAR SKIES WITH MIN TEMPS OF
55 TO 65 DEGREES...COOLEST OVER THE FAR INTERIOR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...
* TEMPS AT OR SLIGHTLY COOLER THAN NORMAL
* SHOWERS LIKELY LATE THU INTO FRI
* NEXT WEEKEND IS TRENDING COOLER BUT MAINLY DRY
SYNOPTIC OVERVIEW...
GOOD MODEL AGREEMENT AMONG THE ECENS AND GEFS ENSEMBLES ON THE
NORTHERN STREAM JET REMAINING AMPLIFIED AND SUPPRESSED ACROSS THE
GREAT LAKES AND NEW ENGLAND THIS PERIOD. THIS WILL RESULT IN A STORM
TRACK ACROSS OR SOUTH OF THE REGION...YIELDING AN ACTIVE WEATHER
PATTERN FOR THE AREA BUT CONFINING ANY SEVERE WEATHER THREAT AND
EXCESSIVE HEAT WELL SOUTH AND SOUTHWEST OF NEW ENGLAND. THIS IS
SUPPORTED BY LATEST TELECONNECTIONS WITH NAO AND AO REMAINING WEAKLY
NEGATIVE DURING THIS FORECAST PERIOD.
SENSIBLE WEATHER...
TUE...
SIGNIFICANT AIRMASS CHANGE BEHIND MON NIGHT/S COLD FRONT WITH PWATS
DIPPING BELOW 1 INCH AND DEW PTS FALLING INTO THE U40S TO L50S!
REFRESHING WNW WIND TO ACCOMPANY THE COOLER/LESS HUMID AIRMASS TUE.
PGRAD LOOKS ROBUST ENOUGH TO PRECLUDE ANY SEABREEZES.
WED...
RIDGE OF HIGH PRES CREST OVER THE REGION AROUND 12Z...THEN SLIPPING
OFFSHORE. THIS WILL RESULT IN A COOL START BUT TEMPS WILL REBOUND
QUICKLY AS STRONG JULY SUNSHINE COMBINES WITH WEAK WARM AIR
ADVECTION AS RETURN FLOW GETS UNDERWAY. DEW PTS WILL INCH UPWARD
ESPECIALLY ALONG THE SOUTH COAST...BUT STILL ANOTHER GEM OF A DAY
WITH PLENTY OF SUNSHINE AND COMFORTABLE TEMPS AND HUMIDITY.
THU/FRI...
NEXT SHORT WAVE AND ATTENDING FRONTAL BOUNDARY APPROACHES THE REGION
LATE THU INTO FRI. FAIRLY AMPLIFIED TROUGH WITH NEGATIVE TILT. ALL
MODELS ESPECIALLY THE ECMWF SUGGEST THIS STRONG FORCING FOR ASCENT
WILL INDUCE A FRONTAL WAVE AND TRACK ALONG OR SOUTH OF NEW ENGLAND.
MORE LIKE A COOL SEASON EVENT THAN A TYPICAL SUMMER FRONTAL SYSTEM.
MODELS ALSO ADVERTISING SOME ELEVATED INSTABILITY ALONG WITH GOOD
MOISTURE ADVECTION AS PWATS CLIMB ABOVE 1.5 INCHES. ALL OF THESE
ATTRIBUTES SUGGEST A RISK FOR ENHANCED QPF. AS FOR TIMING...
SURPRISINGLY AT THIS TIME RANGE ENSEMBLES AND DETERMINISTIC GUID IN
GOOD AGREEMENT WITH HIGHEST PROBABILITY OF RAIN/SHOWERS FROM LATE
THU INTO EARLY FRI. IN FACT 00Z GEFS ENSEMBLES OFFERING LIKELY POPS
DURING THIS TIME PERIOD. TEMPS HERE WILL LIKELY BE ON THE COOL SIDE
GIVEN CLOUD COVER/RAIN AND ESPECIALLY IF SURFACE WAVE TRACKS SOUTH
OF THE REGION.
SAT/SUN...
ECENS AND GEFS ENSEMBLES BOTH HAVE POLAR VORTEX MOVING EQUATORWARD
INTO SOUTH-CENTRAL QUEBEC WITH HEIGHTS OVER NEW ENGLAND DIPPING TO
MINUS 2 STANDARD DEVIATIONS FROM CLIMO! THIS WILL SUPPORT COOLER
TEMPS. DETERMINISTIC RUNS OF THE GFS AND ECMWF ARE EVEN MORE ROBUST.
AS FOR PRECIP...PATTERN SUGGEST DRY WEATHER WITH STORM TRACK
SUPPRESSED SOUTH OF NEW ENGLAND. HOWEVER GIVEN COLD AIR ALOFT CAN/T
RULE OUT ISOLATED DIURNAL SHOWER/TSTM ESPECIALLY HIGHER TERRAIN.
FOR NEXT WEEK ALL MODEL GUID INDICATING POTENTIAL RECORD COOL TEMPS
FOR NEW ENGLAND AS POLAR VORTEX MAY CONTINUE TO DIG SOUTHWARD
THROUGH QUEBEC.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERALL...MODERATE CONFIDENCE BUT LOW CONFIDENCE ON CAPE/ISLANDS.
TODAY...ACROSS EAST COASTAL MA IFR/LIFR CIGS/VSBYS TO START IN
STRATUS AND FOG...IMPROVING TO MVFR AFTER 12-13Z...THEN IMPROVING TO
VFR BY 18Z. ON CAPE/AND ISLANDS A PERIOD OF IFR CONDITIONS IS
EXPECTED TO FORM PRIOR TO 12Z AND LAST FOR A FEW HOURS...THEN CIGS
IMPROVE TO VFR BY 18Z. OVER THE INTERIOR...MVFR/LOCALIZED IFR
CIGS/VSBYS IN FOG IMPROVE TO VFR AFTER 12Z. ISOLD-SCT SHOWERS DURING
THE MORNING...AND EARLY AFTERNOON EAST COASTAL MA THRU 19Z.
TONIGHT...HIGH CONFIDENCE VFR.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. IFR/LIFR CIGS/VSBYS
PERSIST THRU 13Z...THEN CIGS/VSBYS GRADUALLY IMPROVE AFTER 13Z. CIGS
IMPROVE TO VFR BY 18Z.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS/VSBYS SHOULD
DEVELOP FOR A PERIOD OF TIME EARLY THIS MORNING...BECOMING VFR BY
13Z. SCATTERED SHOWERS POSSIBLE THRU 15Z.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...HIGH CONFIDENCE FOR VFR AND DRY WEATHER. SEABREEZES
LIKELY WED.
THU AND FRI...A PERIOD OF MVFR/IFR POSSIBLE ALONG WITH SHOWERS
LIKELY. HIGH CONFIDENCE ON SHOWERS BUT LOWER CONFIDENCE ON EXACT CIG
AND VSBY CATEGORIES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE.
TODAY...COLD FRONT APPROACHES THE WATERS TODAY BUT WINDS ARE
EXPECTED TO BE 15KT OR LESS. SEAS ON THE SOUTHERN OUTER COASTAL
WATERS EXPECTED TO PRIMARILY BE 2 TO 4 FT BUT THERE IS A CHANCE FOR
5 FT SEAS FOR A SHORT TIMEFRAME.
TONIGHT...WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA THRESHOLDS.
COLD FRONT CROSSES THE WATERS WITH WINDS BECOMING NW AROUND 10 KT
AFTER MIDNIGHT.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...FINE BOATING WEATHER WITH HIGH PRES IN CONTROL OF THE
NORTHEAST. TRANQUIL SEAS GIVEN LIGHT WINDS AND SMALL SWELLS. GOOD
VSBY AS WELL.
THU AND FRI...STRONG FRONTAL SYSTEM AND SURFACE WAVE LIKELY WITH LOW
TRACKING ALONG OR NEAR SOUTHERN NEW ENGLAND COAST. SHOWERS AND FOG
WILL YIELD POOR VSBY. LOW CONFIDENCE ON WIND FORECAST GIVEN
UNCERTAINTY ON EXACT TRACK AND INTENSITY OF LOW.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/NMB
NEAR TERM...NOCERA/NMB
SHORT TERM...NMB
LONG TERM...NOCERA
AVIATION...NOCERA/NMB
MARINE...NOCERA/NMB
AREA FORECAST DISCUSSION
NWS MIAMI FL
910 AM EDT MON JUL 29 2013
.UPDATE...
LIGHT SE WIND FLOW HAS BECOME RE-ESTABLISHED OVER THE AREA WITH
COASTAL SHOWERS/TSTMS ATLANTIC AND EAST COAST THIS MORNING.
CURRENT FORECAST OF AFTERNOON CONVECTION SHIFTING TO INTERIOR AND
WESTERN SECTIONS OF SOUTH FLORIDA LOOKS ON TRACK AND IS CONSISTENT
WITH HIGH-RESOLUTION MODELS SUCH AS HRRR AND WRF. SOME MINOR
ADJUSTMENTS MAY BE NEEDED IN THE LATE MORNING FORECAST UPDATE,
PRIMARILY TO INCREASE POPS SLIGHTLY FROM THE 30/40 RANGE CURRENTLY
DEPICTED FOR THE INTERIOR AND WEST THIS AFTERNOON. INSTABILITY
PARAMETERS NOT TOO IMPRESSIVE BASED ON 12Z SOUNDING DATA, SO
STORMS THIS AFTERNOON SHOULD BE MAINLY GARDEN VARIETY.
MOLLEDA
&&
.PREV DISCUSSION... /ISSUED 733 AM EDT MON JUL 29 2013/
AVIATION...
A FEW SHRA/TSRA OVER THE ATLANTIC THIS MORNING BUT ONLY NEAR THE
KPBI TERMINAL AT THIS TIME. SOUTHEAST FLOW WILL TEND TO DIMINISH
THIS ACTIVITY DURING THE FIRST COUPLE OF HOURS AND THEN REDEVELOP
INLAND WITH MOVEMENT TOWARDS THE INTERIOR AND SOUTHWEST COAST. VFR
CONDITIONS ARE EXPECTED BUT THERE COULD BE SOME BRIEF MVFR/IFR AT
KAPF THIS AFTERNOON. SEA BREEZES WILL DEVELOP ALONG BOTH COASTS BY
LATE THIS MORNING OR EARLY AFTERNOON.
JE/KOB
PREV DISCUSSION... /ISSUED 426 AM EDT MON JUL 29 2013/
DISCUSSION...
ISOLATED SHOWERS CONTINUE TO DEVELOP ACROSS THE ATLANTIC WATERS THIS
MORNING AS THE MARINE BOUNDARY LAYER MOISTENS. A FEW OF THESE
SHOWERS ARE ALSO BEGINNING TO MAKE THEIR WAY INLAND ACROSS THE EAST
COAST METRO AREAS. THESE SHOWERS SHOULD CONTINUE TO BE LIGHT AND
SPARSE IN NATURE THROUGH THE MORNING.
THE FIRST HALF OF THE WEEK WILL BE MARKED BY THE RETURN OF EASTERLY
FLOW ACROSS THE AREA. DEEP H5 TROUGH ACROSS THE GREAT LAKES WILL
CONTINUE TO RETREAT TO NORTHEAST INTO QUEBEC THROUGH THE DAY. THIS
WILL ALLOW THE BERMUDA HIGH TO BECOME MORE FIRMLY ENTRENCHED ACROSS
THE WESTERN ATLANTIC RESULTING IN PREVAILING EASTERLY FLOW ACROSS
SOUTH FLORIDA. AS A RESULT...THE MAJORITY OF THE AFTERNOON
CONVECTION IS EXPECTED TO BE CONFINED ACROSS THE INTERIOR AND GULF
COASTAL AREAS AS EASTERLY FLOW INTERACTS WITH AN EXPECTED GULF
BREEZE. MODEL SOUNDINGS AGAIN DEPICT STEERING FLOW TO BE VERY WEAK
WHICH WILL RESULT IN SLOW MOVING STORMS AND HEIGHTEN THE RISK OF
URBAN FLOODING. THIS PATTERN IS EXPECTED TO PERSIST THROUGH MIDWEEK
WITH CHANCES FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
EACH DAY.
BY THURSDAY THE REMNANTS OF DORIAN ARE EXPECTED TO BE APPROACHING
THE BAHAMA ISLANDS. THERE IS STILL UNCERTAINTY AS TO WHETHER DORIAN
WILL REGAIN STRENGTH INTO A TROPICAL SYSTEM. CURRENTLY THE NATIONAL
HURRICANE CENTER GIVES A 50% CHANCE RE-INTENSIFICATION INTO A
TROPICAL SYSTEM. HOWEVER...THERE CONTINUES TO BE NO APPARENT SURFACE
CIRCULATION AT THIS TIME. ALSO...BOTH THE GFS AND THE ECMWF DEPICT A
GRADUAL WEAKENING OF THE WAVE AS IT HEADS TOWARD SOUTH FLORIDA. EVEN
SO...IT COULD STILL PRODUCE HEAVY RAINS ACROSS SOUTH FLORIDA
THURSDAY THROUGH FRIDAY AS IT GETS CLOSER. RAISED POPS TO LIKELY
ACROSS THE INTERIOR AND GULF COASTAL AREAS FOR THURSDAY AFTERNOON AND
EVENING. MODELS ALSO DEPICT A HIGHLY AMPLIFIED H5 TROUGH DIGGING
SOUTH INTO THE OHIO VALLEY AND INTO THE DEEP SOUTH BY THURSDAY WHICH
SHOULD ALLOW THE REMNANTS OF DORIAN TO MAKE A MOVE TO THE NORTH AND
GET PICKED UP BY THE TROUGH.
SOUTHEAST SURFACE FLOW SHOULD CONTINUE INTO THE WEEKEND AS MID LEVEL
RIDGING BUILDS BACK ACROSS SOUTH FLORIDA. CHANCES FOR SEA BREEZE
INDUCED SHOWERS AND THUNDERSTORMS WILL ALSO PREVAIL.
AVIATION...
VFR WILL PREVAIL WITH LIGHT WINDS GENERALLY 5 KT OR LESS
OVERNIGHT. THE WIND SHIFT TO THE SE FOR THE ATLANTIC WATERS WILL
CONTINUE ON MONDAY AND INCREASE TO 10 KT IN THE AFTERNOON. FOR
KAPF, WINDS WILL BECOME SW ON MONDAY AFTERNOON WITH SPEEDS NEAR 10
KT. AFTERNOON TSTORMS ARE EXPECTED TO BE FOCUSED INTERIOR AND
WEST...ONLY HAVE VCSH FOR THE EAST COAST TERMINALS AND VCTS FOR
NAPLES.
MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE THROUGH THE MIDDLE OF THE
WEEK WITH A MODERATE EAST TO SOUTHEAST WIND FLOW AND SEAS LESS
THAN 4 FEET. THERE COULD BE A SLIGHT INCREASE IN WIND BY THE
LATTER HALF OF THE WEEK AS A TROPICAL WAVE APPROACHES THE LOCAL
WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 78 88 79 / 20 20 30 20
FORT LAUDERDALE 89 80 89 81 / 20 20 30 20
MIAMI 90 79 89 80 / 20 20 30 20
NAPLES 92 76 92 76 / 30 20 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE...59/MOLLEDA
AVIATION/RADAR/FIRE...30/KOB
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1000 AM EDT MON JUL 29 2013
.UPDATE...
WEAK FRONT IS CURRENTLY DRAPED ACROSS CENTRAL GA. NOT MUCH OF A
WIND SHIFT/TEMP GRADIENT WITH THE BOUNDARY...BUT A DEFINITE DEWPOINT
GRADIENT EXISTS. CONVECTION MOST LIKELY ALONG AND SOUTH OF THE
BOUNDARY TODAY. A FEW STORMS COULD BECOME STRONG PRODUCING GUSTY
WINDS AND LIGHTNING STRIKES. THE POTENTIAL FOR SEVERE STORMS IS
LOW...BUT THE 12Z MODIFIED SOUNDING DOES SHOW SOMEWHAT OF AN
INVERTED V STRUCTURE...SO IF AN ISOLATED SEVERE STORM DOES
DEVELOP...A WET MICROBURST WILL BE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 738 AM EDT MON JUL 29 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TUESDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
AVIATION...
12Z UPDATE...
FOG THIS MORNING HAS MAINLY BEEN LIMITED TO MCN AND AHN. LOW
CLOUDS HAVE BEEN SPORADIC IN LOCATION. WENT AHEAD AND MENTIONED
FEW030 AT ATL BASED ON HISTORY OF OBS...THOUGH ON THE FENCE ABOUT
WHETHER THE FEW WILL COME BACK THIS MORNING. OTHERWISE SHOULD SEE
CU DEVELOPMENT THIS AFTERNOON. CONVECTIVE ACTIVITY SHOULD BE
LIMITED TO CENTRAL GEORGIA THIS AFTERNOON BUT MAINLY ISOLD IN
COVERAGE. NOT ENOUGH OF A CHANCE TO EVEN MENTION AT MCN IN THE TAF.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON WIND AND VSBYS. MEDIUM CONFIDENCE ON CIGS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 69 / 20 5 20 20
ATLANTA 87 67 88 70 / 10 5 10 20
BLAIRSVILLE 82 60 84 64 / 5 5 20 30
CARTERSVILLE 85 61 90 67 / 5 5 10 30
COLUMBUS 91 70 93 72 / 20 5 20 20
GAINESVILLE 87 67 86 70 / 5 5 20 30
MACON 91 67 92 69 / 20 10 20 20
ROME 88 61 91 67 / 5 5 10 30
PEACHTREE CITY 87 62 88 65 / 10 5 20 20
VIDALIA 92 73 90 72 / 30 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
738 AM EDT MON JUL 29 2013
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TUESDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
&&
.AVIATION...
12Z UPDATE...
FOG THIS MORNING HAS MAINLY BEEN LIMITED TO MCN AND AHN. LOW
CLOUDS HAVE BEEN SPORADIC IN LOCATION. WENT AHEAD AND MENTIONED
FEW030 AT ATL BASED ON HISTORY OF OBS...THOUGH ON THE FENCE ABOUT
WHETHER THE FEW WILL COME BACK THIS MORNING. OTHERWISE SHOULD SEE
CU DEVELOPMENT THIS AFTERNOON. CONVECTIVE ACTIVITY SHOULD BE
LIMITED TO CENTRAL GEORGIA THIS AFTERNOON BUT MAINLY ISOLD IN
COVERAGE. NOT ENOUGH OF A CHANCE TO EVEN MENTION AT MCN IN THE TAF.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON WIND AND VSBYS. MEDIUM CONFIDENCE ON CIGS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 69 / 20 5 20 20
ATLANTA 87 67 88 70 / 10 5 10 20
BLAIRSVILLE 82 60 84 64 / 5 5 20 30
CARTERSVILLE 85 61 90 67 / 5 5 10 30
COLUMBUS 91 70 93 72 / 20 5 20 20
GAINESVILLE 87 67 86 70 / 5 5 20 30
MACON 91 67 92 69 / 20 10 20 20
ROME 88 61 91 67 / 5 5 10 30
PEACHTREE CITY 87 62 88 65 / 10 5 20 20
VIDALIA 92 73 90 72 / 30 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
618 AM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 29 2013
TODAY...MULTIPLE MODES OF ATMOSPHERIC UNREST ARE OPERATING ACROSS
THE FCST AREA THIS MORNING AND ARE EXPECTED TO CONTINUE THROUGH
THIS EVENING. STRATUS...FOG...DRIZZLE...SHOWERS PRODUCING DECENT
RAINFALL IN A WARM CLOUD PROCESS ARE OPERATING ACROSS SWRN NEB
THROUGH NCNTL NEBRASKA THIS MORNING. THIS AREA OF WEATHER IS
EXPECTED TO SHIFT EAST THIS MORNING AND COVER AREAS ALONG AND
EAST OF HIGHWAY 183 THIS AFTERNOON. IT IS BELIEVED THAT THE
SHOWERS AND DRIZZLE/FOG SHOULD EXIT BY 18Z AS THIS IS BEING
DRIVEN BY MOISTURE TRANSPORT AT THE 315K SFC AND ACCORDING TO THE
RAP...THIS TRANSPORT SHOULD WEAKEN THIS MORNING.
THE ONGOING MCS ACROSS NWRN NEB IS EXPECTED TO DECAY BY 12Z AS
RADAR SUGGESTS AN OCCLUSION PROCESS IS UNDERWAY ACROSS FAR SWRN
SD. ALSO THE RAP SHOWS MOISTURE TRANSPORT ON THE 315K SFC WILL
WEAKEN.
TEMPERATURES TODAY RANGE FROM 60S ACROSS THE EAST UNDER A BLANKET
OF STRATUS TO 80S ACROSS WRN NEB WHERE IT IS BELIEVED SKIES WILL
CLEAR. THE RAP MODEL SHOWS 750MB CAPE INCREASING TO AROUND 1000
J/KG AND THE NAM THEN SHOWS THE ATM DESTABILIZING ACROSS SWRN AND
WRN NEB LATE THIS AFTERNOON. DOWN DRAFT CAPE NEAR 1000 J/KG COULD
SUPPORT A FEW STORMS WITH GUSTY WINDS...MAINLY THIS EVENING AS
THE STORMS ARE EXPECTED TO ORIGINATE ACROSS THE CYS DIVIDE AND
PARTS OF NERN COLO AND MOVE INTO THE FCST LATE THIS AFTN OR EARLY
EVENING.
TONIGHT...SCATTERED TSTMS ARE EXPECTED TO REMAIN WEST OF HIGHWAY
83 AND MAINLY ALONG AND WEST OF HIGHWAY 61. THE NAM SHOWS THESE
STORMS WEAKENING/DISSIPATING BY 03Z. A WEAK MOSTLY OUTFLOW DRIVEN
COLD FRONT IS EXPECTED TO DRAPE FROM KOGA TO KVTN IN THE WAKE OF
THE STORMS AND LOW LEVEL MOISTURE EAST OF THE FRONT APPEARS
LIKELY TO PRODUCE ANOTHER ROUND OF STRATUS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 29 2013
UPPER LEVEL RIDGE IS GENERALLY ACROSS THE 4 CORNERS REGION...AND
WILL BUILD EAST TOWARDS THE WEEKEND. MEANWHILE AN UPPER LEVEL
TROUGH/LOW WILL PUSH ACROSS CANADA MID WEEK...WITH THE LOW
REACHING THE SRN PART OF HUDSON BAY BY THE WEEKEND. OVER THE HIGH
PLAINS FLOW WILL BE NORTHWEST THROUGH THE WEEK...WITH A TRANSITION
TO MORE ZONAL BY WEEKEND.
AT THE SFC..COOL CANADIAN HIGH PRESSURE ACROSS THE CENTRAL PLAINS
EARLY...WILL SLOWLY PUSH EAST...WITH A WARM UP EXPECTED. THEN A
COLD FRONT WILL PUSH ACROSS THE AREA WEDNESDAY WITH ANOTHER COOL
DOWN TO END THE WEEK. HIGHS SHOULD RETURN TO THE 80S...NEAR OR
SLIGHTLY BELOW SEASONAL BY MID WEEK...AHEAD OF THE FRONT. BY FRIDAY
AS THE COOLER HIGH PRESSURE PUSHES ACROSS THE CENTRAL
PLAINS...TEMPS TO COOL BACK INTO THE UPPER 70S TO LOWER 80S. AFTER
THE EXTENT OF THE LATEST COOL DOWN...WILL HAVE TO MONITOR CLOSELY
THE COOLER AIR AS A TREND DOWN IN TEMPS IS POSSIBLE.
MODELS IN AGREEMENT WITH AN ACTIVE PATTERN TO CONTINUE THROUGH THE
WEEK WITH SEVERAL DISTURBANCES TO RIDE THE PERIPHERY OF THE RIDGE
AND ACROSS THE AREA. MOISTURE REMAINS DECENT WITH DEW PTS IN THE
UPPER 50S TO LOWER AND MID 60S. WITH EACH QUICK MOVING WAVE EXPECT
SHOWERS AND A FEW THUNDERSTORMS TO BE POSSIBLE.
ON WEDNESDAY...WITH THE PASSAGE OF THE COLD FRONT AND COOLER AIR
ALOFT...THERE COULD BE A FEW STRONG THUNDERSTORMS. TIMING AND
PLACEMENT OF THE BEST INSTABILITY STILL IN QUESTION...AND WILL BE
WATCH OVER THE NEXT COUPLE OF DAYS. THE REST OF THE WEEK WILL
CONTINUE TO SEE A CHANCE FOR SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH EACH PASSING WAVE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 618 AM CDT MON JUL 29 2013
IT LOOKS LIKE THE IFR/LIFR CIGS/VSBY WILL LIFT NORTHEAST INTO
NCNTL NEBRASKA THIS AFTERNOON. FOR TONIGHT WE ARE EXPECTING A
RETURN TO IFR/LIFR...MAINLY AFTER 06Z AND THE AREA AFFECTED WOULD
BE FROM KIML NORTHEAST THROUGH KVTN. THE CONCERN IS FOG
DEVELOPMENT WHICH COULD IN SOME AREAS BECOME DENSE ACCORDING TO
THE GUIDANCE WHICH HAS MODERATE SKILL IN THESE TYPES OF EVENTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
912 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH FROM THE NORTHWEST TODAY...THEN
SLIDE OFFSHORE EARLY TUESDAY. THE FRONT WILL LINGER NEAR THE COAST
INTO WEDNESDAY BEFORE DISSIPATING. HIGH PRESSURE OFFSHORE WILL
DOMINATE LATE IN THE WEEK. ANOTHER COLD FRONT WILL APPROACH FROM
THE NORTHWEST SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 910 AM MONDAY...WIDESPREAD CONVECTION CONTINUES OUT OVER THE
GULF STREAM WITH A SMALL CLUSTER OF SHOWERS OVER THE NORTHERN
OUTER BANKS AND A COUPLE OF ISOLATED SHOWERS OVER PAMLICO COUNTY.
THE NSSL...REGIONAL WRF AND HRRR ALL INDICATE SHOWERS/TSTMS
REFORMING ALONG THE SEA BREEZE AROUND 16-17Z AND MOVING INLAND.
MADE ONLY MINOR ADJUSTMENTS TO THE POPS...BASED ON A CONSENSUS OF
THESE MODELS. WITH TEMPERATURES RUNNING A COUPLE OF DEGREES AHEAD
OF PROJECTIONS...DID BUMP MAX TEMPS UP A DEGREE OR TWO FOR THE
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 220 AM MON...WEAK FRONT WILL CROSS REGION TONIGHT. LIMITED
FORCING ALOFT AND MDLS NOT INDICATING MUCH PRECIP OVER AREA.
INLAND AREAS SEE A DECENT DROP IN PRECIP WTR SO CONT PREV FCST OF
NO POPS INLAND TO SMALL CHC CLOSER TO CST. LOWS WILL RANGE FROM
UPR 60S/AROUND 70 WELL INLAND TO MID 70S BEACHES.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 4 AM MON...A COLD FRONT WILL DISSIPATE ALONG THE COAST TUES
WITH THE SEA BREEZE BECOMING DOMINANT ALONG THE SOUTH COAST IN THE
AFTERNOON. PWATS DROP TO AROUND 1.2" NORTH OF HIGHWAY 70 BUT
REMAIN AROUND 1.7" SOUTHERN SECTIONS...THOUGH THE NAM DOES SHOW
SOME RECOVERY NORTH IN THE AFTERNOON. NEAR ZONAL FLOW ALOFT WITH
LACK OF FORCING WILL LIMIT CONVECTION WITH THE BEST CHANCE
SOUTHERN AREAS ALONG THE SEA BREEZE.
SLY FLOW RETURNS WED BRINGING A RESURGENCE OF PWATS UP TO 2" BY
THE AFTERNOON WHILE THE UPPER LEVEL WILL EXPERIENCE HEIGHT FALLS
IN RESPONSE TO AN UPPER TROUGH DIGGING ACROSS THE MID WEST. A
SERIES OF SHORTWAVE ENERGY WILL MOVE THROUGH FLOW ALOFT WED
THROUGH THU BRINGING THE BEST FORCING AND HIGHEST POPS THROUGH THE
LONG TERM. A COLD FRONT WILL APPROACH THE REGION LATE THU BUT
MODELS STALL THE FRONT TO THE WEST THU NIGHT.
THE UPPER TOUGH AXIS MOVES OFFSHORE THU NIGHT WITH A DRIER AIRMASS
MOVING INTO THE REGION FRI WITH PWATS FORECAST TO DROP TO 1-1.4"
DURING THE AFTERNOON. EXPECT TYPICAL SUMMERTIME PATTERN FRI AND
SAT WITH THE BERMUDA HIGH OFFSHORE AND THE PIEDMONT TROUGH INLAND.
ZONAL TO SLIGHT CYCLONIC FLOW ALOFT WITH NO UPPER LEVEL FORCING
WILL YIELD NEAR TO SLIGHTLY BELOW CLIMO POPS FOR JULY. A COLD
FRONT APPROACHING FROM THE NW AND SHORTWAVE ENERGY ALOFT WILL
BRING BETTER CHANCES FOR CONVECTION SUN.
TEMPS THROUGH THE LONG TERM WILL BE NEAR NORMAL FOR THE MOST PART
WITH HIGHS IN THE UPPER 80S TO AROUND 90 INLAND AND MID 80S ALONG
THE COAST...THOUGH ABUNDANT CLOUD COVER AND GREATER COVERAGE OF
PCPN THU COULD KEEP HIGHS IN THE MID 80S.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 645 AM MON...AREAS OF MVFR/IFR FOG/STRATUS HV DEVELOPED ACROSS
THE AREA. THESE LOW CLOUDS AND FOG SHLD LIFT/DISSIPATE FAIRLY
QUICKLY AFTER SUNRISE WITH VFR BECOMING DOMINANT FROM MID MORN ON.
SOME WDLY SCT TO SCT CONVECTION POSS LATE MORN THRU AFTN...HOWEVER
IMPACTS TO TERMINALS WILL BE BRIEF IF AT ALL. CONT VFR THIS EVENING
THEN WILL AGAIN HAVE THREAT FOR SOME SCT MVFR/IFR STRATUS AND FOG
LATE TONIGHT AS WINDS GO LIGHT TO CALM WITH WEAK FRONT CROSSING.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...A COLD FRONT DISSIPATES ALONG THE SOUTH COAST TUE
WITH DRIER AIR FILTERING IN FROM THE NORTH...BEST CHANCE OF
CONVECTION SOUTHERN SECTIONS ALONG THE SEABREEZE. UPPER TROUGHING
AND A COLD FRONT APPROACHING FROM THE WEST WED AND THU BRINGING
BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD.
LESSENING CHANCES OF CONVECTION FRI AS THE UPPER TROUGH SLIDES
EAST OF THE REGION WITH THE FRONT STALLING TO THE WEST. PATCHY
LATE NIGHT EARLY MORNING FOG AND STRATUS POSSIBLE EACH DAY THROUGH
THE LONG TERM.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/
AS OF 910 AM MONDAY...NO BIG CHANGES TO THE CURRENT MARINE
FORECAST EXCEPT TO SLIGHTLY INCREASE WINDS TO 10 TO 15 KNOTS OVER
THE SOUNDS AND FAR NORTHERN WATERS BASED ON CURRENT OBSERVATIONS.
SW WINDS OF 15 KNOTS OR LESS SHOULD CONTINUE THROUGH THE DAY. LIGHT
WSW WINDS AHEAD OF THE FRONT IN THE EVENING WILL BECOME LIGHT NNE
LATE. SEAS WILL AVG 2 TO 4 FEET THRU THE PERIOD.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...LIGHT NE WINDS AOB 10 KT EARLY TUE BECOME
ERLY DURING THE AFTERNOON AS A COLD FRONT DISSIPATES ALONG THE
SOUTHERN COASTAL AREAS. SE WINDS AOB 10 KT DOMINATE TUE NIGHT AND
WED WITH HIGH PRES CENTERED OFFSHORE. SW WINDS AROUND 10-15 KT
DEVELOP WED NIGHT AND STRENGTHEN TO 15-20 KT THU AS A TROUGH
LIFTS NORTH THROUGH THE WATERS AND PRES GRADIENTS TIGHTEN BETWEEN
THE BERMUDA HIGH OFFSHORE AND A FRONT APPROACHING FROM THE W. THE
FRONT STALLS W OF THE AREA THU NIGHT/FRI WITH GRADIENTS WEAKENING
SOME WITH SW WINDS MAINLY 10-15 KT BY FRI. SEAS GENERALLY 2-4 FT
THROUGH WED...THEN BUILD TO 3-5 FT WED NIGHT-FRI IN RESPONSE TO
STRONGER SW FLOW.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...SK
AVIATION...RF/SK
MARINE...CTC/RF/SK
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1027 AM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 1027 AM CDT MON JUL 29 2013
TRICKY PRECIPITATION FORECAST TODAY AND TONIGHT. WILL FOLLOW THE
LATEST RAP FOR THE MORNING UPDATE WHICH APPEARS TO BEST REFLECT
CURRENT REALITY. TWO AREAS OF SHOWERS/THUNDERSTORMS TO BE CONCERNED
WITH TODAY. THE FIRST IS AN CLUSTER OF SHOWERS NORTH AND WEST OF
ABERDEEN ALONG THE NOSE OF A 30 KT 850 HPA JET AND MID-LEVEL
MOISTURE GRADIENT. THE SECOND IS A LINE OF SHOWERS AND EMBEDDED
THUNDERSTORMS FROM STANLEY TO NORTHWEST OF DICKINSON ASSOCIATED
WITH THE MAIN SURFACE TROUGH AND SHORT-WAVE ALOFT. THE RAP
SUGGESTS THESE TWO AREAS OF PRECIPITATION WILL CONVERGE WEST OF
THE FORECAST AREA THIS AFTERNOON AND THEN MOVE INTO THE VALLEY IN
SOME FORM LATER THIS EVENING. BEST MIXED LAYER INSTABILITY (UP TO
1500 J/KG) WILL BE CONFINED TO THE DEVILS LAKE BASIN...SO SOME
STRONG TO MARGINALLY SEVERE STORMS ARE POSSIBLE IN THIS AREA. FOR
NOW...NOT CERTAIN ON STORM AREAL COVERAGE...SO WILL KEEP POPS IN
THE CHANCE CATEGORY INCREASING FROM WEST TO EAST LATE THIS
AFTERNOON AND EVENING.
LARGE MID-HIGH LEVEL CLOUD SHIELD HAS DEVELOPED AHEAD OF THE
SURFACE TROUGH AND THIS MAY IMPACT TEMPERATURES TODAY. FOR NOW...
INCREASED SKY GRIDS AND SLOWED THE RISE OF HOURLY TEMPERATURES...
BUT KEPT AFTERNOON HIGHS IN THE MID TO UPPER 70S. DEPENDING ON
EVOLUTION OF CLOUDS...MAY HAVE TO KNOCK THESE VALUES DOWN A FEW
DEGREES AT THE 1 PM FORECAST UPDATE.
UPDATE ISSUED AT 640 AM CDT MON JUL 29 2013
CONVECTION IN NORTH CENTRAL ND ALONG THE CANADIAN BORDER LOOKS
LIKE IT WILL AT MOST CLIP NORTHWESTERN TOWNER COUNTY. THUS...WILL
CONTINUE TO KEEP ONLY MINIMAL POPS IN THE NORTHWESTERN CWA UNTIL
LATER THIS AFTERNOON. MINOR TWEAKS TO TEMPS AND WINDS BUT NO MAJOR
CHANGES.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
CONVECTION CHANCES THROUGHOUT THE PERIOD WILL BE THE PRIMARY
FORECAST CONCERN.
THE MAIN UPPER RIDGE AXIS OVER WESTERN MN WILL CONTINUE TO SHIFT
EASTWARD TODAY AS NEAR ZONAL FLOW SETS IN. CONVECTION HAS BEEN
ONGOING SINCE AROUND MIDNIGHT IN NORTHWESTERN ND. THINK THAT THIS
ACTIVITY WILL START TO DISSIPATE AS IT MOVES FURTHER EAST INTO
STABLE AIR. HOWEVER...WILL KEEP AN EYE ON IT AND MAY MAKE SOME
LAST MINUTE ADJUSTMENTS.
SHORTWAVE OVER ID SHOULD MOVE OUT INTO THE NORTHERN PLAINS TODAY.
SOUTHERLY WINDS WILL BE PICKING UP AS THE SFC TROUGH AXIS MOVES
INTO ND...SO THERE SHOULD BE SOME RETURN FLOW. ON THE OTHER
HAND...MODELS ARE IN PRETTY DECENT AGREEMENT THAT THE BEST
INSTABILITY AXIS WILL REMAIN TO OUR WEST THIS AFTERNOON. THINK
THAT SOME PRECIP MAY ENTER THE DEVILS LAKE BASIN THIS
AFTERNOON...BUT THE EASTERN TWO THIRDS OF THE CWA WILL NOT SEE
MUCH UNTIL TONIGHT. AT THIS POINT IT SEEMS THAT STORMS MOVING
THROUGH WILL BE SUB SEVERE.
NEAR ZONAL FLOW CONTINUES INTO TUESDAY...WITH A STRONGER SHORTWAVE
TROUGH MOVING INTO MANITOBA. A SFC TROUGH AXIS WILL SET UP OVER
THE CENTRAL CWA AND COULD BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT. SFC BASED CAPE VALUES WILL BE AROUND 1500 J/KG...AND
DEEP LAYER BULK SHEAR WILL BE AROUND 40 KTS OR SO. THE MAIN COLD
FRONT AND UPPER FORCING DO NOT MOVE IN UNTIL TUESDAY NIGHT THOUGH
SO JUST KEPT POPS IN THE 30 PERCENT RANGE BEFORE 00Z.
AS FOR TEMPERATURES...CONTINUED A SLOW WARMING TREND WITH HIGHS
BACK AROUND 80 DEGREES IN SOME AREAS FOR TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
TUESDAY NIGHT...A COLD FRONT MOVING THROUGH ALONG WITH THE MAIN UPPER
TROUGH DIGGING DOWN OUT OF CANADA SHOULD PROVIDE THE FOCUS FOR
CONTINUED THUNDERSTORM DEVELOPMENT. BUMPED UP POPS A BIT INTO THE
HIGH CHANCE RANGE FOR OVERNIGHT HOURS...WITH A BIT OF PRECIP
LINGERING IN THE SOUTHEAST WEDNESDAY MORNING. WEDNESDAY AND
WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH SFC HIGH PRESSURE
BUILDING IN AND NORTHWESTERLY FLOW ALOFT. TEMPS WILL GET KNOCKED
BACK A BIT INTO THE 70S BEHIND THE COLD FRONT ON WEDNESDAY.
THURSDAY-SUNDAY...
A VERY STAGNANT UPPER FLOW PATTERN IS EXPECTED TO PERSIST THROUGH
THE MAJORITY OF THIS PERIOD. NORTHWEST FLOW ALOFT WILL BE MAINTAINED
ACROSS THE NORTHERN PLAINS IN BETWEEN A BLOCKING UPPER LEVEL RIDGE
ACROSS WESTERN CANADA AND A TROUGH OVER EASTERN CANADA...WITH THE
SUBTROPICAL RIDGE REMAINING ANCHORED ACROSS THE SOUTHERN HIGH
PLAINS. THIS PATTERN WILL KEEP DEEP MOISTURE SOUTH OF THE
REGION...AND PRECIP CHANCES LOW OVERALL...ALTHOUGH A FEW SHOWERS ARE
POSSIBLE WITH ANY WAVES DROPPING OUT OF CANADA.
TEMPS ON THURSDAY MAY APPROACH SEASONAL NORMS IN THE 70S TO NEAR 80.
HOWEVER...OPERATIONAL MODELS SUGGEST A STRONGER WAVE WILL PUSH
THROUGH THURSDAY NIGHT...WITH BROAD SFC HIGH PRESSURE NOSING INTO
THE NORTHERN PLAINS FOR LATE WEEK. A SURGE OF REINFORCING COOLER AIR
AMIDST NORTHERLY LOW-LEVEL FLOW WILL KEEP TEMPS BELOW NORMAL THROUGH
NEXT WEEKEND.
BY LATE NEXT WEEKEND...THE 00Z GFS/ECMWF TEMPORARILY FLATTEN THE
UPPER FLOW AND KICK THE WESTERN US UPPER LOW EASTWARD...WITH THE 00Z
ECMWF A BIT MORE ROBUST WITH MOISTURE RETURN AND PRECIP CHANCES.
CONFIDENCE IN ANY SCENARIO AT THIS RANGE IS LOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 640 AM CDT MON JUL 29 2013
VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD WITH NO BR
FORMING OVER THE EAST THIS MORNING. MID AND HIGH CLOUDS WILL
CONTINUE TO SPREAD OVER THE AREA FROM THE WEST. SHOWERS AND
THUNDERSTORMS WILL BEGIN MOVING INTO THE WESTERN FORECAST AREA
THIS AFTERNOON AND SPREAD EASTWARD OVERNIGHT. HOWEVER...CONFIDENCE
IS NOT HIGH ENOUGH AT SPECIFIC LOCATIONS TO INCLUDE A MENTION
EXCEPT AT KDVL. WINDS WILL SHIFT AROUND TO THE SOUTH AND PICK UP
TO NEAR 10 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
825 AM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 825 AM CDT MON JUL 29 2013
LATEST WATER VAPOR IMAGERY AND LOCAL/REGIONAL RADAR SHOWS A COUPLE
OF SHORTWAVES LINING UP FROM CENTRAL MONTANA INTO CENTRAL NORTH
DAKOTA THIS MORNING. UPPER DIVERGENCE FIELD PER SREF SEEMS TO MESH IN
PRETTY WELL WHERE SHOWERS/THUNDERSTORMS ARE DEVELOPING...ESPECIALLY
OVER THE WEST AND NORTH CENTRAL. THE LATEST HRRR MODEL IS
FORECASTING A LINE OF SHOWERS AND THUNDERSTORMS TO IMPINGE ON OUR
WESTERN BORDER BY 17Z TO 18Z WITH A PROGRESSIVE/EASTWARD MOVEMENT
THIS AFTERNOON INTO SOUTH CENTRAL NORTH DAKOTA. THIS SEEMS
REASONABLE PER UPSTREAM WEATHER IN CENTRAL MONTANA.
FOR THIS MORNINGS UPDATE...BASED ON THE ABOVE...HAVE HAVE BOOSTED
POPS WEST AND NORTH CENTRAL...AND CHANGED WORDING TO AREAL
COVERAGE/SCATTERED...VERSUS UNCERTAINTY. BISMARCK SOUNDING AND
CLOUD COVER OUTSIDE OF THE OFFICE STILL SHOWS A CAP IS IN
PLACE...BUT WITH THE APPROACH OF THE UPSTREAM SHORTWAVES...ENOUGH
COOLING ALOFT WILL ALLOW FOR SCATTERED THUNDERSTORMS THIS
AFTERNOON. THUS HAVE MENTIONED ISOLATED SHOWERS FOR THE MORNING
AND THEN INTRODUCED THUNDER FOR THE AFTERNOON FROM BISMARCK EAST.
UPDATE ISSUED AT 636 AM CDT MON JUL 29 2013
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS...OTHERWISE LITTLE CHANGE TO THE GOING FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON JUL 29 2013
THE SHORT RANGE MODELS...INCLUDING THE HIGH RESOLUTION CONVECTIVE
SHORT TERM MODELS...WERE DOING A POOR JOB WITH CONVECTION
OCCURRING AT THE TIME OF THIS WRITING. THIS HAS BEEN THE CASE FOR
THE PAST 24 HOURS AS WELL. THE MODEL GUIDANCE IS REASONABLE...
BASED ON POSITION OF SURFACE LOW TROUGH THROUGH EASTERN MONTANA
AND PLACEMENT AND MOVEMENT OF MID LEVEL DISTURBANCES...IT IS JUST
THAT THE ATMOSPHERE IS NOT COOPERATING AND REACTING AS EXPECTED.
HAVE NOW CASTED THE ONGOING CONVECTION FOR THE NEXT 8 HOURS AND
THEN...IN COLLABORATION WITH NEIGHBORING OFFICES...BLANKETED THE
WEST WITH CHANCE POPS...AND SPREAD THEM EAST THROUGH THE DAY.
AS THE SURFACE TROUGH MOVES INTO THE WESTERN DAKOTAS TODAY...AND
MOISTURE POOLS AROUND IT ON SOUTHEAST SURFACE WINDS AND
INCREASINGLY MOIST (HIGHER DEW POINT) AIR...ENOUGH INSTABILITY
SHOULD BE RELEASED TO TRIGGER DEEP MOIST CONVECTION ACROSS EASTERN
MONTANA AND THE WESTERN DAKOTAS. THIS WILL BE AIDED BY THE NEXT
WEAK MID LEVEL WAVE APPROACHING.
SEVERE WEATHER PARAMETERS ARE LACKING...SO AS FAR AS SEVERE
CONVECTION GOES...NOTHING BUT ISOLATED SEVERE IS ANTICIPATED.
TONIGHT...AS THE SYSTEM MOVES EAST...STORMS WILL END FROM THE
WEST...IN THE EVENING FROM WILLISTON TO DICKINSON...AND BY
MIDNIGHT FROM MINOT TO BISMARCK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON JUL 29 2013
MEDIUM TO LONG RANGE FORECAST MODELS ARE IN DECENT AGREEMENT FOR
MUCH OF THE LONG TERM FORECAST PERIOD.
MODELS CONTINUE TO INDICATE AN ACTIVE TUESDAY/TUESDAY
NIGHT...ESPECIALLY ALONG TO SOUTH OF INTERSTATE 94 WHERE A LINGERING
SFC BOUNDARY/COLD FRONT WILL COINCIDE WITH DIVERGENT FLOW ALOFT IN
THE RRQ OF AN UPPER LEVEL JET STREAK AND MUCAPE NEARING 1-1.5K J/KG
MID TO LATE AFTERNOON. FARTHER NORTH...A POTENT MID LEVEL TROUGH
WILL SWING EAST ACROSS SOUTH CENTRAL CANADA...INTO LAKE WINNIPEG
LATE AFTERNOON. THIS WILL DRIVE THE SFC COLD FRONT SOUTH INTO SOUTH
DAKOTA BY MID EVENING. BEST CHANCE OF SEVERE WEATHER STILL LOOKS
FROM THE INTERSTATE 94 CORRIDOR COUNTIES SOUTH INTO SOUTH DAKOTA
WITH INSTABILITY TAPERING OFF TO THE NORTH OF THE FRONT. MAIN
QUESTION IS WILL THE MORNING CONVECTION ADVERTISED BY MODELS OVER
EASTERN MONTANA/WESTERN NORTH DAKOTA AND RESULTANT CLOUD COVER BE
ENOUGH TO SHUN THE SEVERE POTENTIAL? OR ARE MODELS PERHAPS
SUGGESTING STRONG TO SEVERE CONVECTION ONGOING TUESDAY MORNING BEING
MAINTAINED THROUGH THE AFTERNOON ALONG THE FRONTAL BOUNDARY?
REGARDLESS...POP WILL BE HIGH GIVEN THE DYNAMICS IN PLACE WITH THE
MAIN QUESTION BEING HOW STRONG WILL THE STORMS BE. WILL MAINTAIN A
HIGH POP FOR MOST LOCATIONS TUESDAY MORNING...AFTERNOON...AND
EVENING...TRENDING DOWN LATE TUESDAY NIGHT/EARLY WED MORNING.
AFTER TUESDAY NIGHT...NORTHWEST FLOW ALOFT DEVELOPS ALONG WITH
SURFACE HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA INTO EASTERN
SOUTH DAKOTA. STABLE AIR ACCOMPANIES THE SFC HIGH SO HAVE REMOVED
ALL MENTION OF PRECIPITATION WED/WED NIGHT...AND TRENDED DOWN
THURSDAY/THURS NIGHT LEAVING A THUNDERSTORM MENTION FAR SOUTH AND
FAR WEST FOR NOW. FOR FRIDAY...PATTERN REMAINS IN PLACE ALTHOUGH WE
DO START TO SEE RETURN FLOW WEST WHERE I HAVE KEPT THUNDERSTORMS IN
THE FORECAST.
LATEST 00Z MODELS DEVELOP A QUASI-ZONAL FLOW OVER THE NORTHERN
PLAINS FOR NEXT WEEKEND WHICH WOULD RESULT IN BETTER CHANCES FOR
MORE WIDESPREAD SHOWERS/THUNDERSTORMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY)
ISSUED AT 430 AM CDT MON JUL 29 2013
NOW CASTING THE CONVECTION UPSTREAM WOULD YIELD NO THUNDERSTORMS AT
ANY TAF SITE THROUGH 29/16Z. AT 29/0910Z THUNDERSTORMS WERE
DEVELOPING THROUGH CENTRAL MONTANA. THEY WILL INCREASE TODAY AND
MOVE INTO NORTH DAKOTA...FROM WEST TO EAST...AS THE NEXT MID LEVEL
WAVE MOVES THROUGH...SUPPORTED AT THE SURFACE BY A TROUGH ALONG
THE MONTANA / DAKOTAS BORDER. SCATTERED STORMS ARE FORECAST AFTER
29/16Z WEST...ADVANCING SLOWLY EAST THROUGH THE DAY...REACHING
KJMS AFTER 29/23Z. EXPECT SOUTHEAST SURFACE WINDS 10 TO 15
KNOTS...GUSTY IN AND NEAR STORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JPM
LONG TERM...NH
AVIATION...JPM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
749 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM EASTERN NEW YORK TO CENTRAL GEORGIA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND WILL REMAIN
ACROSS THE MID ATLANTIC INTO TUESDAY. LOW PRESSURE COMING OUT OF
THE CENTRAL PLAINS WILL APPROACH THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT MONDAY...
MSAS LIFTED INDEX ANALYSIS AND SURFACE PRESSURE FROM 07Z/3AM
SHOWED COLD FRONT FROM JUST EAST OF LYNCHBURG TO JUST SOUTH OF
MARTINSVILLE. ISOLATED SHOWERS WERE JUST EAST OF THE FRONT WITH A
SUBTLE SHORT WAVE COMING THROUGH THE BASE OF THE TROF HELPING
TRIGGER THE PRECIPITATION. LOCAL WRF AND 06Z RUC GUIDANCE LINED UP
WELL WITH THE CURRENT LOCATIONS OF THE PRECIPITATION. BOTH OF
THESE MODELS HAD ALL OF THE PRECIPITATION OUT OF THE FORECAST AREA
BY 10Z/6AM. CLOUDS IN THE EAST WILL TAKE LONGER TO EXIT THE
FORECAST AREA...BUT BY 15Z/11AM...MUCH OF THE REGION WILL BE
MOSTLY SUNNY. SURFACE DEW POINTS HAVE DROPPED INTO THE LOWER 50S
ACROSS WEST VIRGINIA. MODELS HAVE ALL DEW POINTS IN THE FORECAST
AREA DROPPING BELOW 60S DEGREES BY 21Z/5PM. A SLIGHT DOWNSLOPE
WIND WILL BRING THE DRIER AIR ALOFT DOWN TO THE SURFACE EAST OF
THE BLUE RIDGE THIS AFTERNOON. USED A BLEND OF MET/MAV GUIDANCE
FOR AFTERNOON HIGHS. VALLEYS WILL DECOUPLE TONIGHT SO FOLLOWED
COOLER NUMBERS THERE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
AN UPPER LEVEL LOW OVER THE GREAT LAKES THIS MORNING WILL TRAVEL
NORTHEAST INTO THE CANADIAN MARITIMES TUESDAY INTO WEDNESDAY. HIGH
PRESSURE WILL SLIDE EAST ACROSS OUR REGION TUESDAY AND PUSH INTO THE
ATLANTIC WEDNESDAY. COOLER AND DRIER WEATHER EXPECTED TUESDAY. BELOW
NORMAL HIGHS TEMPERATURES WILL RANGE FROM THE LOWER 70S IN THE
MOUNTAINS TO THE MID 80S IN THE PIEDMONT.
MOISTURE OVERRUNS THE RIDGE TUESDAY NIGHT WITH THE CHANCE FOR RAIN
TO RETURN IN THE SOUTHWESTERN PORTIONS OF FORECAST AREA. WITH
ADDITIONAL CLOUD COVER...PLAYED LOW TEMPERATURES CLOSER TO THE
WARMER MOS GUIDANCE TUESDAY NIGHT WITH READINGS THE MID 50S IN THE
MOUNTAINS TO UPPER 60S IN THE SOUTHEAST. LOW TEMPERATURES COULD BE
COOLER ESPECIALLY IN THE NORTHWEST MOUNTAINS IF CLOUD COVER OR
MOISTURE AND SHORTWAVE DOES NOT ARRIVAL OR IS SLOWER. GOOD CHANCE
OF RAIN WEDNESDAY AND WEDNESDAY NIGHT AS AN INSITU WEDGE TAKES
RESIDENCE OVER THE AREA. LEANING TOWARDS A NAM/ECMWF BLEND...RAIN
SHOULD SPREAD NORTHEAST ACROSS OUR REGION WEDNESDAY. THE BEST CHANCE
OF RAIN IS ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS WITH A
PERSISTENT SOUTHEAST FLOW. WITH THE RAIN KEPT THE ADVERTISED COOLER
HIGHS WEDNESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO LOWER 80S IN
THE PIEDMONT. ALLOWED FOR SOME THUNDERSTORMS IN WEST. USED THE
ENSEMBLE LOWS FOR WEDNESDAY NIGHT FROM THE LOWER 60S IN THE WEST TO
AROUND 70 DEGREES IN THE EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 AM EDT MONDAY...
STRATIFORM RAIN WILL GIVE WAY TO SHOWERS ON THURSDAY...AS A SURFACE
WAVE TRACKS NORTH ALONG A FRONT. THIS FRONT IS EXPECTED TO CLEAR THE
AREA THURSDAY EVENING. SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
WILL BRING DRY WEATHER BACK INTO THE REGION THURSDAY NIGHT INTO
SATURDAY. THEN THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
INCREASES ON SUNDAY WITH THE APPROACH OF ANOTHER COLD FRONT.
ON THURSDAY...AS A SURFACE WAVE TRACKS NORTH ALONG A FRONT. THIS
FRONT IS EXPECTED TO CLEAR THE AREA THURSDAY EVENING. SURFACE HIGH
PRESSURE AND ZONAL FLOW ALOFT WILL BRING DRY WEATHER BACK INTO THE
REGION THURSDAY NIGHT INTO SATURDAY. THEN THE NEXT CHANCE FOR
SHOWERS AND THUNDERSTORMS INCREASES ON SUNDAY WITH THE APPROACH OF
ANOTHER COLD FRONT.
TEMPERATURES SHOULD REBOUND TOWARD NORMAL ON THURSDAY AS THE RAIN
MOVES EAST. TEMPERATURES WILL BE AT OR ABOVE NORMAL NEXT WEEKEND
UNTIL THE FRONT PASSES TO THE EAST.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 730 AM EDT MONDAY...
SHALLOW GROUND FOG AT BCB/LWB/BLF WILL DISSIPATE BY 14Z/10AM.
THESE SITES PLUS ROA/LYH/DAN WILL BE VFR FOR THE REST OF THE DAY.
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY...AND INFLUENCE
THE WEATHER PATTERN THROUGH TUESDAY. VFR CONDITIONS ARE EXPECTED
THROUGH TONIGHT. THE EXCEPTION WILL BE VALLEY FOG WITH IFR TO LIFR
VISIBILITIES OVERNIGHT...INCLUDING AT LWB. HIGH CONFIDENCE OF FOG
FORMATION AGAIN TONIGHT AT KLWB.
ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA.
EXPECT A RETURN OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS AS EARLY AS LATE TUESDAY NIGHT ACROSS THE WEST.
FOR THURSDAY AND FRIDAY...AN UPPER RIDGE STRETCHES EAST WITH
MOUNTAIN THUNDERSTORMS EXPECTED DURING EACH AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
726 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM EASTERN NEW YORK TO CENTRAL GEORGIA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND WILL REMAIN
ACROSS THE MID ATLANTIC INTO TUESDAY. LOW PRESSURE COMING OUT OF
THE CENTRAL PLAINS WILL APPROACH THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT MONDAY...
MSAS LIFTED INDEX ANALYSIS AND SURFACE PRESSURE FROM 07Z/3AM
SHOWED COLD FRONT FROM JUST EAST OF LYNCHBURG TO JUST SOUTH OF
MARTINSVILLE. ISOLATED SHOWERS WERE JUST EAST OF THE FRONT WITH A
SUBTLE SHORT WAVE COMING THROUGH THE BASE OF THE TROF HELPING
TRIGGER THE PRECIPITATION. LOCAL WRF AND 06Z RUC GUIDANCE LINED UP
WELL WITH THE CURRENT LOCATIONS OF THE PRECIPITATION. BOTH OF
THESE MODELS HAD ALL OF THE PRECIPITATION OUT OF THE FORECAST AREA
BY 10Z/6AM. CLOUDS IN THE EAST WILL TAKE LONGER TO EXIT THE
FORECAST AREA...BUT BY 15Z/11AM...MUCH OF THE REGION WILL BE
MOSTLY SUNNY. SURFACE DEW POINTS HAVE DROPPED INTO THE LOWER 50S
ACROSS WEST VIRGINIA. MODELS HAVE ALL DEW POINTS IN THE FORECAST
AREA DROPPING BELOW 60S DEGREES BY 21Z/5PM. A SLIGHT DOWNSLOPE
WIND WILL BRING THE DRIER AIR ALOFT DOWN TO THE SURFACE EAST OF
THE BLUE RIDGE THIS AFTERNOON. USED A BLEND OF MET/MAV GUIDANCE
FOR AFTERNOON HIGHS. VALLEYS WILL DECOUPLE TONIGHT SO FOLLOWED
COOLER NUMBERS THERE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
AN UPPER LEVEL LOW OVER THE GREAT LAKES THIS MORNING WILL TRAVEL
NORTHEAST INTO THE CANADIAN MARITIMES TUESDAY INTO WEDNESDAY. HIGH
PRESSURE WILL SLIDE EAST ACROSS OUR REGION TUESDAY AND PUSH INTO THE
ATLANTIC WEDNESDAY. COOLER AND DRIER WEATHER EXPECTED TUESDAY. BELOW
NORMAL HIGHS TEMPERATURES WILL RANGE FROM THE LOWER 70S IN THE
MOUNTAINS TO THE MID 80S IN THE PIEDMONT.
MOISTURE OVERRUNS THE RIDGE TUESDAY NIGHT WITH THE CHANCE FOR RAIN
TO RETURN IN THE SOUTHWESTERN PORTIONS OF FORECAST AREA. WITH
ADDITIONAL CLOUD COVER...PLAYED LOW TEMPERATURES CLOSER TO THE
WARMER MOS GUIDANCE TUESDAY NIGHT WITH READINGS THE MID 50S IN THE
MOUNTAINS TO UPPER 60S IN THE SOUTHEAST. LOW TEMPERATURES COULD BE
COOLER ESPECIALLY IN THE NORTHWEST MOUNTAINS IF CLOUD COVER OR
MOISTURE AND SHORTWAVE DOES NOT ARRIVAL OR IS SLOWER. GOOD CHANCE
OF RAIN WEDNESDAY AND WEDNESDAY NIGHT AS AN INSITU WEDGE TAKES
RESIDENCE OVER THE AREA. LEANING TOWARDS A NAM/ECMWF BLEND...RAIN
SHOULD SPREAD NORTHEAST ACROSS OUR REGION WEDNESDAY. THE BEST CHANCE
OF RAIN IS ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS WITH A
PERSISTENT SOUTHEAST FLOW. WITH THE RAIN KEPT THE ADVERTISED COOLER
HIGHS WEDNESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO LOWER 80S IN
THE PIEDMONT. ALLOWED FOR SOME THUNDERSTORMS IN WEST. USED THE
ENSEMBLE LOWS FOR WEDNESDAY NIGHT FROM THE LOWER 60S IN THE WEST TO
AROUND 70 DEGREES IN THE EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 AM EDT MONDAY...
STRATIFORM RAIN WILL GIVE WAY TO SHOWERS ON THURSDAY...AS A SURFACE
WAVE TRACKS NORTH ALONG A FRONT. THIS FRONT IS EXPECTED TO CLEAR THE
AREA THURSDAY EVENING. SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
WILL BRING DRY WEATHER BACK INTO THE REGION THURSDAY NIGHT INTO
SATURDAY. THEN THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
INCREASES ON SUNDAY WITH THE APPROACH OF ANOTHER COLD FRONT.
ON THURSDAY...AS A SURFACE WAVE TRACKS NORTH ALONG A FRONT. THIS
FRONT IS EXPECTED TO CLEAR THE AREA THURSDAY EVENING. SURFACE HIGH
PRESSURE AND ZONAL FLOW ALOFT WILL BRING DRY WEATHER BACK INTO THE
REGION THURSDAY NIGHT INTO SATURDAY. THEN THE NEXT CHANCE FOR
SHOWERS AND THUNDERSTORMS INCREASES ON SUNDAY WITH THE APPROACH OF
ANOTHER COLD FRONT.
TEMPERATURES SHOULD REBOUND TOWARD NORMAL ON THURSDAY AS THE RAIN
MOVES EAST. TEMPERATURES WILL BE AT OR ABOVE NORMAL NEXT WEEKEND
UNTIL THE FRONT PASSES TO THE EAST.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 130 AM EDT MONDAY...
SHALLOW GROUND FOG AT BCB/LWB/BLF WILL DISSIPATE BY 14Z/10AM.
THESE SITES PLUS ROA/LYH/DAN WILL BE VFR FOR THE REST OF THE DAY.
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY...AND INFLUENCE
THE WEATHER PATTERN THROUGH TUESDAY. VFR CONDITIONS ARE EXPECTED
THROUGH TONIGHT. THE EXCEPTION WILL BE VALLEY FOG WITH IFR TO LIFR
VISIBILITIES OVERNIGHT...INCLUDING AT LWB. HIGH CONFIDENCE OF FOG
FORMATION AGAIN TONIGHT AT KLWB.
ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA.
EXPECT A RETURN OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS AS EARLY AS LATE TUESDAY NIGHT ACROSS THE WEST.
FOR THURSDAY AND FRIDAY...AN UPPER RIDGE STRETCHES EAST WITH
MOUNTAIN THUNDERSTORMS EXPECTED DURING EACH AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
957 AM CDT MON JUL 29 2013
.UPDATE...CLOUDS ACROSS THE NORTHEAST HALF OF THE FORECAST AREA
ARE FAIRLY THIN GIVEN LATEST GRB SOUNDING AND RAP MODEL SOUNDINGS.
CONSEQUENTLY...THE SUN IS BEGINNING TO POKE THROUGH IN
SPOTS...WITH INCREASED HEATING/MIXING LIKELY TO HELP CLEAR THINGS
UP THROUGH LATE MORNING. THUS STILL EXPECTING HIGH TEMPS INTO THE
70S ACROSS THE FORECAST AREA THIS AFTERNOON.
&&
.AVIATION/18Z TAFS/...MVFR CIGS ACROSS THE NORTHEAST HALF OF THE
FORECAST AREA WILL IMPROVE BY LATE MORNING AS DAYTIME/HEATING
MIXING EATS AWAY AT THE LOW CLOUD DECK. SHOULD SEE A GOOD AMOUNT
OF SUN THEN FOR THE AFTERNOON.
IT SHOULD BE QUIET TONIGHT...WITH INCREASING MOISTURE POSSIBLY
BRINGING A RETURN OF SOME LOW CLOUDS AND A CHANCE FOR SHOWERS
TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT MON JUL 29 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
IMMEDIATE FORECAST CONCERN IS EARLY MORNING CLOUD COVER. LATEST
11-3.9 MICRON IMAGERY SHOWING RENEWED SWD PROGRESSION OF STRATUS
SHIELD OVER PORTIONS OF EAST CENTRAL WI. HOWEVER MORE BREAKS IN
THE CLOUDS OVER SOUTHEAST WI AS DRIER AIR AND INCREASING
SUBSIDENCE BUILD INTO THE REGION. STRATUS APPEARS FAIRLY SOLID
NORTH OF KSBM INTO NORTHEAST WI. WITH LOW LEVEL THERMAL TROUGH
LINGERING OVER EASTERN WI AT 12Z BEFORE WEAKENING...LIKELY TO BE
PERIOD OF BKN-OVC CLOUDS EARLY OVER THE EAST BEFORE THINNING.
EXPECT MORE CU TO REDEVELOP LATER THIS MRNG AND EARLY AFTN BUT
SHOULD REMAIN FEW-SCT FOR THE AFTN. WINDS TO TURN ONSHORE BY EARLY
AFTN...WHICH WILL KEEP LAKESHORE AREAS A FEW DEGREES COOLER.
BOTH GFS AND NAM INCREASE WEAK FORCING AFTER MIDNIGHT OVER SOUTH
CENTRAL WI AS LOW TO MID LEVEL MOISTURE RETURNS. PRECIPITABLE
WATER VALUES INCREASE AROUND THREE QUARTERS INCH BY 12Z IN THIS
AREA. HOWEVER 00Z NAM OUTLIER WITH STRONGER LOW LEVEL CONVERGENCE
ASSOCD WITH 85H JET AND APPROACHING WEAK MID-LEVEL 7H WAVE. NAM
ALSO SHOWING LITTLE CONSISTENCY FROM EARLIER RUNS. FOR NOW...WL
CONTINUE DRY FORECAST THRU 12Z WITH SCHC POPS SPREADING IN ON TUE.
SOME LIGHT FOG POSSIBLE IN LIGHT BOUNDARY LAYER WINDS LATER
TONIGHT IN ERN CWA BEFORE CLOUDS THICKEN.
TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
SHORT TERM MODELS SHOWING SOME DISAGREEMENT WITH FEATURES DURING
THIS PERIOD. THE NAM/CANADIAN/ECMWF SHOW LOW PRESSURE PASSING
SOUTH OF THE REGION TUESDAY INTO TUESDAY NIGHT. NAM ONLY MODEL
BRINGING QPF INTO THE SOUTHERN COUNTIES WITH THIS FEATURE...AS
850MB WARM AIR ADVECTION AND LOW LEVEL JET NOSE FOCUSES INTO
PORTIONS OF THE AREA. NAM MAY BE OVERDONE WITH THESE FEATURES AS
IT TENDS TO BE.
NAM FORECAST SOUNDINGS SHOW FAIRLY DEEP MOISTURE TUESDAY...BECOMING
SHALLOWER TUESDAY NIGHT. LITTLE TO NO INSTABILITY SHOWING UP
DURING THIS TIME. GFS DOES NOT SHOW THE LOW PASSING SOUTH OF THE
REGION TUESDAY INTO TUESDAY NIGHT.
THE CANADIAN AND GFS SHOW QPF WITH A PASSING 500MB VORTICITY
MAXIMUM MAINLY TUESDAY NIGHT INTO EARLY WEDNESDAY. THE ECMWF IS
FAIRLY DRY DURING THIS TIME. GFS FORECAST SOUNDINGS SHOWING
SIMILAR MOISTURE PROFILES TO THE NAM TUESDAY INTO TUESDAY
NIGHT...WITH A BIT MORE INSTABILITY. GFS SEEMS TO BE ODD MODEL OUT
DURING THIS TIME WITH ITS LACK OF A LOW TO THE SOUTH.
THE GFS/CANADIAN/ECMWF THEN BRING SURFACE COLD FRONT/500MB
VORTICITY MAXIMUM SOUTHEAST THROUGH THE REGION WEDNESDAY INTO
EARLY WEDNESDAY EVENING...WITH THE NAM AROUND 6 HOURS SLOWER. ALL
MODELS SHOW QPF WITH THE FRONTAL PASSAGE...WITH NAM/GFS FORECAST
SOUNDINGS SHOWING TALL SKINNY MEAN LAYER CAPE. DRIER AIR THEN
WORKS INTO THE AREA LATER WEDNESDAY NIGHT WITH COLD AIR ADVECTION.
GIVEN THE DIFFERENCES AMONG THE MODELS DURING THIS PERIOD...LEANED
TOWARDS CONSENSUS POPS AND TEMPERATURES. THIS LEFT LOWER END POPS
FOR TUESDAY INTO TUESDAY NIGHT...WITH HIGHER POPS WEDNESDAY INTO
WEDNESDAY EVENING WITH THE FRONTAL PASSAGE. TEMPERATURES SHOULD
REMAIN SLIGHTLY BELOW SEASONAL NORMALS.
THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
GFS/ECMWF THEN SHOW FAIR AGREEMENT IN THIS PERIOD. THURSDAY LOOKS
DRY WITH HIGH PRESSURE INFLUENCE STILL OVER THE AREA. MODELS IN
BETTER AGREEMENT WITH COLD FRONTAL PASSAGE AND QPF TIMING ON
FRIDAY...WITH GFS WETTER THAN ECMWF WITH QPF. 500MB VORTICITY
MAXIMUM PASSES THROUGH FRIDAY AS WELL. HIGH PRESSURE FROM THE
NORTH THEN BRINGS COOLER AND DRIER AIRMASS INTO THE REGION
SATURDAY INTO SUNDAY ACROSS THE REGION.
GIVEN SOME OF THE DIFFERENCES IN THIS PERIOD...WENT WITH CONSENSUS
POPS AND TEMPERATURES. HIGHEST POPS WILL BE FRIDAY INTO FRIDAY
NIGHT WITH THE FRONTAL PASSAGE. TEMPERATURES SHOULD REMAIN AROUND
OR SLIGHTLY BELOW SEASONAL NORMALS.
AVIATION/12Z TAFS/...BRIEF PERIOD OF MVFR CIGS MAY AFFECT ERN
TAF SITES EARLY THIS MRNG AS LAST VESTIGES OF LOW LEVEL COLD AIR
ADVECTION AND THERMAL TROF LINGER IN THE AREA BEFORE SHIFTING OFF
TO THE EAST. OTRW...MAINLY FEW-SCT CU EXPCD TO REDEVELOP LATER
THIS MRNG AND AFTN. VFR CONDITIONS TO CONTINUE TNGT. ERN TAF SITES
MAY EXPERIENCE LIGHT FOG AFT MIDNIGHT DUE TO LIGHT BOUNDARY LAYER
FLOW BEFORE MID/HIGH CLOUDS THICKEN LATE.
MARINE...NORTHWEST WINDS WILL CONTINUE TO SUBSIDE AS PRESSURE
GRADIENT RELAXES OVER LAKE MI THIS MORNING. EXPECT WINDS TO TURN
ONSHORE LATE THIS MRNG AND EARLY AFTERNOON AS LAKE BREEZE
DEVELOPS. WINDS LOOK TO REMAIN MAINLY LESS THAN 20 KNOTS FOR THE
FORESEEABLE FUTURE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...MBK
TUESDAY THROUGH SUNDAY...WOOD
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
938 AM MDT MON JUL 29 2013
.UPDATE...
ISSUED AT 935 AM MDT MON JUL 29 2013
MINOR CHANGES TO TODAYS FORECAST. LOWERED POPS THE REST OF THIS
MORNING AND DECREASED SKY COVER. STILL EXPECTING ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON AS
THE LOW LEVELS DESTABILIZE. CLOUD COVER HAS SLOWED THE RISE OF
TEMPERATURES THIS MORNING BUT THE HIGH TEMPERATURE FORECAST LOOKS
IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 547 AM MDT MON JUL 29 2013
IFR CONDITIONS WILL CONTINUE OVER MUCH OF THE PLAINS THROUGH THE
MID-MORNING. LOW CLOUDS WILL THEN SCATTER OUT BY LATE MORNING.
EXPECT SHOWERS AND TSTMS TO DEVELOP ALONG THE LARAMIE RANGE BY THE
EARLY AFTN THEN SPREAD EASTWARD OVER THE PLAINS THROUGH THE
EVENING. WINDS WILL GENERALLY BE LESS THAN 15 KTS...EXCEPT NEAR
STORMS WHERE BRIEF GUSTY WINDS WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...FINCH
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
558 AM MDT MON JUL 29 2013
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 547 AM MDT MON JUL 29 2013
IFR CONDITIONS WILL CONTINUE OVER MUCH OF THE PLAINS THROUGH THE
MID-MORNING. LOW CLOUDS WILL THEN SCATTER OUT BY LATE MORNING.
EXPECT SHOWERS AND TSTMS TO DEVELOP ALONG THE LARAMIE RANGE BY THE
EARLY AFTN THEN SPREAD EASTWARD OVER THE PLAINS THROUGH THE
EVENING. WINDS WILL GENERALLY BE LESS THAN 15 KTS...EXCEPT NEAR
STORMS WHERE BRIEF GUSTY WINDS WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...FINCH
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
426 AM MDT MON JUL 29 2013
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1051 PM MDT SUN JUL 28 2013
PROLONGED AND EXPANSIVE IFR EVENT UNDERWAY WITH LOW CEILINGS AT
KAIA...KSNY AND JUST RECENTLY HERE AT KCYS. HRR HAS A GREAT HANDLE
ON THIS STRATUS AND USED IT FOR MY GUIDANCE ON THE 06Z TAFS.
STRATUS TO STAY IN WHERE IT IS IN THE SOUTHERN/CENTRAL PANHANDLE
AND HERE AT KCYS THROUGH 12Z. THEN BEGINS TO LIFT AT KCYS AFTER
13Z OR SO. MAY TAKE A LITTLE LONGER TO BREAK IN THE PANHANDLE.
CONCERN IS FOR KCDR. THEY ARE GOING TO SEE A LINE OF SHOWERS MOVE
THROUGH UP THERE THAT SHOULD HELP KEEP THEM UP FOR A WHILE. WITH A
SOUTHEAST DOWNSLOPE WIND OFF THE PINE RIDGE...CONFIDENCE IS
SOMEWHAT HIGH THAT THEY SHOULD STAY MVFR OR BETTER THROUGH THE
OVERNIGHT HOURS.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 AM MST MON JUL 29 2013
.SYNOPSIS...MOST OF THE AREA WILL SEE A BREAK IN MONSOON STORMS
TODAY AND TUESDAY AS DRIER AIR HAS MOVED ACROSS THE AREA. THE
EXCEPTION WILL BE NEAR THE STATE BORDER WITH NEW MEXICO AND ALONG
THE INTERNATIONAL BORDER FROM NOGALES EAST. THE DAILY CYCLE OF
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL THEN OCCUR
DURING THE LATTER PART OF THIS WEEK AND NEXT WEEKEND. HOTTER DAYTIME
TEMPERATURES WILL OCCUR TODAY THROUGH WEDNESDAY FOLLOWED BY A
COOLING TREND BY NEXT WEEKEND.
&&
.DISCUSSION...SCATTERED TO BROKEN MOSTLY THIN CIRRIFORM CLOUDS FROM
TUCSON EWD WITH MOSTLY CLEAR SKIES ACROSS WRN PIMA COUNTY AT THIS
TIME. DEWPOINTS VALID 16Z RANGED FROM THE MID 40S ACROSS WRN PIMA
COUNTY TO THE MID 60S IN FAR SERN SECTIONS. THESE TEMPS WERE NEARLY
5-15 DEGS F LOWER VERSUS 24 HOURS AGO. 29/12Z KTWC SOUNDING DEPICTED
A FAIRLY DRY PROFILE...AND EVEN DRIER VERSUS 24 HOURS AGO...WITH
TOTAL PRECIP WATER NEAR 1.05 INCHES. THE ENVIRONMENT WAS MORE STABLE
VERSUS 24 HOURS AGO...WITH LIFTED INDEX OF PLUS 2 AND NO CAPE.
29/12Z UPPER AIR PLOTS FEATURED A 592 DM HIGH PRESSURE CENTERED OVER
SE TEXAS...AND 584 DM LOW PRESSURE CENTERED JUST OFF THE SRN
CALIFORNIA COAST VICINITY. LIGHT GENERALLY SWLY FLOW PREVAILED OVER
SE AZ.
29/12Z NAM AND RUC HRRR WERE QUITE SIMILAR TO THE OFFICIAL FORECAST
IN DEPICTING QPF/S THIS AFTERNOON AND EARLY THIS EVENING ACROSS THE
WHITE MOUNTAINS...AND MOSTLY NEAR THE CHIRICAHUA MOUNTAINS AND
HUACHUCA MOUNTAINS IN COCHISE COUNTY. DRY CONDITIONS ARE FORECAST TO
OCCUR ELSEWHERE INTO THIS EVENING. EXPECT DRY CONDITIONS AREA WIDE
LATE TONIGHT. HIGH TEMPS THIS AFTERNOON WILL BE NEARLY IDENTICAL OR
ABOUT 2-4 DEGS F WARMER VERSUS SUNDAY DEPENDING UPON LOCATION.
THERE ARE NO UPDATES PLANNED AT THIS TIME. PLEASE REFER TO THE
PREVIOUS DISCUSSION SECTION BELOW FOR ADDITIONAL DETAIL.
&&
.PREV DISCUSSION /234 AM MST MON JUL 29 2013/...TUESDAY...UPPER HIGH
WILL CONTINUE TO SLOWLY MIGRATE NORTH INTO WEST CENTRAL NEW MEXICO.
FLOW ALOFT WILL BECOME MORE EASTERLY WITH MODELS SUGGESTING A WEAK
INVERTED TROF EXTENDING FROM NORTHERN CHIHUAHUA TO SOUTHERN SONORA
MEXICO. WILL SEE A SLIGHT INCREASE IN PRECIPITABLE WATER ACROSS THE
AREA...WITH THE BEST CHANCE FOR AFTERNOON/EVENING STORMS BEING SOUTH
OF SAN SIMON TO TUBAC LINE AND UP IN THE WHITES. HIGHS WILL BE AT OR
SLIGHTLY WARMER THAN WHAT IS FORECAST FOR TODAY.
WEDNESDAY...UPPER HIGH ACROSS CENTRAL NEW MEXICO WITH EASTERLY FLOW
ACROSS THE AREA. THE AREA WILL AGAIN SEE A SLIGHT INCREASE IN
PRECIPITABLE WATER. AREAL COVERAGE OF STORMS WILL ALSO INCREASE WITH
SLIGHT CHANCES AS FAR WEST AS CENTRAL PIMA COUNTY. THE HOTTEST HIGHS
IN THIS FORECAST CYCLE LIKELY WILL OCCUR TO CLOSE OUT JULY.
THURSDAY THROUGH SUNDAY...LOW TO MID GRADE MONSOON FORECAST AS MOIST
E-SE FLOW CONTINUES WITH UPPER HIGH OVER TEXAS. HIGHS WILL GRADUALLY
COOL DURING THE PERIOD.
&&
.AVIATION...VALID THRU 30/18Z. FEW-SCT080 SCT-BKN350. AFT 29/20Z
ISOLD TSRA THRU 30/04Z OVER THE WHITE MTNS...ALG NEW MEXICO BORDER
AND ACROSS SOUTHERN COCHISE COUNTY...WITH WIND GUSTS UP TO 40 KTS
NEAR TSRA. OTHERWISE...SURFACE WIND GENERALLY 10 KTS AND DIURNAL IN
DIRECTION. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...DRIER CONDITIONS WILL BE IN PLACE OVER THE REGION
THROUGH TUESDAY WITH LOWER HUMIDITIES AND A SMALL THREAT OF
THUNDERSTORMS LIMITED TO NEAR THE STATE BORDER WITH NEW MEXICO AND
ALONG THE INTERNATIONAL BORDER FROM NOGALES EAST. AS THE WEEK
PROGRESSES...MOISTURE VALUES ACROSS THE REGION WILL GRADUALLY
INCREASE WITH AN UPPER HIGH TO OUR EAST. THIS WILL LEAD TO AN
INCREASE IN THUNDERSTORMS DURING THE SECOND HALF OF THE WEEK AND
CONTINUING INTO THE UPCOMING WEEKEND. WINDS THROUGH THE PERIOD WILL
BE DIURNALLY DRIVEN AND GENERALLY BELOW 15 MPH OUTSIDE ANY
THUNDERSTORM ACTIVITY.
&&
.CLIMATE...RAINFALL THAT OCCURRED IN DOUGLAS ON SUNDAY RAISED THE
JULY TOTAL TO OVER 10" AND THEIR MONSOON TOTAL TO 10.23". THE
DOUGLAS MONSOON TOTAL CURRENTLY RANKS AS THE 11TH WETTEST MONSOON ON
RECORD. WITH 64 DAYS LEFT IN THE 2013 MONSOON...DOUGLAS HAS AN
OUTSIDE SHOT AT THREATENING THE ALL-TIME WETTEST MONSOON TOTAL OF
15.90" WHICH OCCURRED IN 1964.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
PREVIOUS DISCUSSION/CLIMATE...JG
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
137 PM EDT MON JUL 29 2013
.PREV DISCUSSION... /ISSUED 1000 AM EDT MON JUL 29 2013/
UPDATE...
WEAK FRONT IS CURRENTLY DRAPED ACROSS CENTRAL GA. NOT MUCH OF A
WIND SHIFT/TEMP GRADIENT WITH THE BOUNDARY...BUT A DEFINITE DEWPOINT
GRADIENT EXISTS. CONVECTION MOST LIKELY ALONG AND SOUTH OF THE
BOUNDARY TODAY. A FEW STORMS COULD BECOME STRONG PRODUCING GUSTY
WINDS AND LIGHTNING STRIKES. THE POTENTIAL FOR SEVERE STORMS IS
LOW...BUT THE 12Z MODIFIED SOUNDING DOES SHOW SOMEWHAT OF AN
INVERTED V STRUCTURE...SO IF AN ISOLATED SEVERE STORM DOES
DEVELOP...A WET MICROBURST WILL BE POSSIBLE.
PREV DISCUSSION... /ISSUED 738 AM EDT MON JUL 29 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TUESDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
&&
.AVIATION...
18Z UPDATE...
CONVECTION SHOULD MAINLY REMAIN SOUTH OF ATL TODAY AND TOMORROW.
NO CIG/VSBY RESTRICTIONS EXPECTED AT THE NORTHERN TERMINALS...BUT
SOME PATCHY FOG IS POSSIBLE AT THE SOUTHERN SITES. TOWARDS
SUNRISE...THE MODELS ARE PROGGING A BRIEF WIND SHIFT TO THE
NE...BUT SPEEDS SHOULD BE BLO 6 KT. WILL LEAVE OUT OF TAFS FOR
NOW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON WINDS. HIGH CONFIDENCE REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 69 89 69 / 20 10 20 20
ATLANTA 87 68 88 70 / 10 10 20 20
BLAIRSVILLE 82 61 84 64 / 10 5 30 30
CARTERSVILLE 85 63 90 67 / 10 5 10 30
COLUMBUS 91 73 93 72 / 30 20 20 20
GAINESVILLE 87 67 86 70 / 10 5 20 30
MACON 91 71 92 69 / 40 20 20 20
ROME 88 63 91 67 / 10 5 10 30
PEACHTREE CITY 87 66 88 65 / 10 10 20 20
VIDALIA 92 74 90 72 / 50 30 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....ATWELL
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS GRAY ME
102 PM EDT MON JUL 29 2013
.SYNOPSIS...
LOW PRESSURE NEAR HUDSON BAY WILL DRAG A TRAILING COLD FRONT ACROSS
THE AREA LATE THIS AFTERNOON...THEN OFFSHORE TONIGHT. AN UPPER LOW WILL
CROSS NORTH OF THE REGION TUESDAY. A WEAK RIDGE OF HIGH PRESSURE
WILL BRING A PLEASANT DAY WITH SUNNY SKIES FOR WEDNESDAY. A SERIES
OF DISTURBANCES WILL CROSS THE REGION THURSDAY THROUGH SUNDAY
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1259 PM...CONVECTION FIRING FROM THE UPPER CONNECTICUT RIVER
VALLEY NORTHEASTWARD INTO FAR NORTHERN OXFORD COUNTY MAINE. HAVE
UPDATED THE FORECAST TO ACCOUNT FOR THIS AS RAP MODEL IS HANDLING
THE CURRENT TRENDS FAIRLY WELL. FOLLOWED A RAP/NAM MIX INTO THIS
EVENING. STORM PREDICTION CENTER STILL SHOWING A VERY SLIGHT
CHANCE OF SEVERE WEATHER IN OUR AREA THIS AFTERNOON AND EVENING.
AT THIS TIME STORMS ARE MOSTLY GOING UP AND DOWN WITHOUT INCIDENT.
939 AM...ADJUSTED MAINLY POP AND SKY COVER TO MATCH CURRENT TRENDS.
STILL BELIEVE THAT INLAND WESTERN MAINE AND NORTHERN AND CENTRAL
NEW HAMPSHIRE THIS AFTERNOON WILL BE THE FOCUS FOR ANY CONVECTION
THAT CAN GET GOING. AFTERNOON HEATING WILL BE THE KEY TO
THUNDERSTORMS OCCURRING. STORM PREDICTION CENTER HAS HIGHLIGHTED
NORTHERN NEW ENGLAND FOR A VERY LOW RISK OF SEVERE THIS AFTERNOON
-- MAINLY CONTINGENT UPON RECEIVING SUFFICIENT HEATING FOR
CONVECTION TO FIRE.
615 AM...I ADJUSTED 1ST PERIOD GRIDS BASED ON RADAR TRENDS AS WELL
AS THE 10Z MESONET FOR THIS ESTF UPDATE.
PREV DISC...
AT 06Z...A 1015 MILLIBAR LOW AND A WAVY FRONTAL BOUNDARY WERE
SITUATED ACROSS THE GULF OF MAINE. A 1011 MILLIBAR LOW WAS
CENTERED SOUTHEAST OF HUDSON BAY WITH A TRAILING COLD FRONT OVER
EASTERN NEW YORK STATE.
THE COLD FRONT WILL SLIDE EASTWARD TODAY ACCOMPANIED BY SCATTERED
SHOWERS AND THUNDERSTORMS. THE SOUTHERLY TRAJECTORY AND MARINE
INFLUENCE WILL LIMIT CONVECTION SOMEWHAT FOR THE MIDCOAST AND
ADJACENT INTERIOR. IF WE SEE SEVERAL HOURS OF CLEARING AND HEATING
TODAY...THE MODELS SUGGEST THAT A FEW STRONG STORMS ARE POSSIBLE
ACROSS EASTERN NEW HAMPSHIRE INTO WESTERN MAINE. I`VE INCLUDED
ENHANCED WORDING FOR HAIL AND GUSTY WINDS IN THE GRIDS FOR
PORTIONS OF THE FORECAST AREA LATER TODAY. HIGHS TODAY WILL RANGE
FROM NEAR 70F MIDCOAST TO THE LOWER 80S FOR SOUTHERN INTERIOR
SECTIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
THE FRONT CLEARS THE COAST TONIGHT WITH A FEW LINGERING CLOUDS
ACROSS NORTHERN SECTIONS WITH THE UPPER TROUGH ALONG WITH WIDELY
SCATTERED SHOWERS.
ON TUESDAY...MOUNTAIN CLOUDS AND SCATTERED SHOWERS WITH THE UPPER
TROUGH OTHERWISE PARTLY SUNNY WITH SEASONABLE HIGHS IN THE 70S AND
LOWER 80S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
SPOKES OF AN UPPER LEVEL TROUGH OVER CANADA AND THE EASTERN CONUS
WILL CONTINUE TO ROTATE THROUGH NORTHERN NEW ENGLAND BRINGING
PERIODS OF SHOWERS AND THUNDERSTORMS IN THE EXTENDED PERIOD.
WEDNESDAY WILL BE DRY HOWEVER AS WE WILL BE UNDER THE INFLUENCE OF
WEAK RIDGING AND IN BETWEEN TWO SHORT WAVES. TEMPERATURES INCREASE
A FEW DEGREES OVER THE PREVIOUS DAY WITH LOWER TO MID 80S ALONG
THE COAST AND SOUTH. SKIES WILL BE MOSTLY SUNNY WITH LIGHT WINDS.
SURFACE HIGH PRESSURE PASSES TO OUR SOUTH AND INTO THE EASTERN
ATLANTIC THURSDAY. INCREASING SOUTHERLY FLOW AND MORE INTENSE
TROUGHING WILL CREATE SHOWERS AND THUNDERSTORMS THURSDAY AND
FRIDAY. RAIN SHOULD START LATER THURSDAY AS A WARM FRONT LIFTS
OVER THE REGION...FOLLOWED BY A SURFACE TROUGH AXIS HELPING TO
FOCUS CONVECTION FRIDAY NIGHT. THE UPPER LEVEL TROUGH STAGNATES
WITH BLOCKING HIGH PRESSURE BUILDING OVER THE ATLANTIC. THIS WILL
KEEP NEW ENGLAND HUMID AND WARM WITH PERIODS OF SHOWERS...AS A
TRUE COLD FRONT DOESN`T ARRIVE TO USHER IN COOLER DRIER AIR UNTIL
PERHAPS NEXT MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY/...VFR CEILINGS WITH SCT MVFR IN
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. AREAS OF
MVFR TONIGHT IN FOG WITH LCL IFR CONDITIONS POSSIBLE TOWARDS DAWN
TUES IN FOG. VFR EXPECTED TUE.
LONG TERM...PERIODS OF MVFR VISIBILITIES IN FOG MOST MORNINGS.
LOWER CEILINGS IN SHOWERS THURSDAY AFTERNOON THROUGH FRIDAY NIGHT.
&&
.MARINE...
SHORT TERM /THROUGH TUESDAY/...WINDS AND SEAS WILL REMAIN BLO SCA
CONDS. LCL VSBY RESTRICTIONS IN FOG POSSIBLE THROUGH TONIGHT.
LONG TERM...WINDS AND SEAS EXPECTED TO BE BELOW SCA CRITERIA.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SHORT TERM...STJEAN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1203 PM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND THEN
CROSS THE REGION TONIGHT. ANOTHER TROUGH OF LOW PRESSURE WILL CROSS
THE REGION ON TUESDAY...FOLLOWED BY HIGH PRESSURE BUILDING ACROSS
THE REGION WEDNESDAY AND MOVING EAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1130 AM UPDATE: BASED ON THE LATEST RADAR IMAGERY AND HRRR MODEL
PROJECTIONS OF FUTURE EVOLUTION OF CNVCTN THIS AFTN INTO THIS
EVE...WE OPTD TO DELAY THE ONSET OF HIER POPS ASSOCIATED WITH TSTM
DEVELOPMENT TIL LATER THIS AFTN FOR MOST OF THE FA. THIS BASED ON
THE SLOWER ONSET OF ANY SUNSHINE ACROSS THE FA TO HELP INITIATE
TSTMS. LATEST HRRR MODEL RUNS SUGGEST THAT THE STRONGEST TSTMS
LATE THIS AFTN WILL BE OUT WEST WHERE THE LONGEST PD OF SUNSHINE
IS XPCTD...WITH A LN OF SCT-BKN TSTMS WEAKENING AS IT MOVES INTO
NE AND E CNTRL PTNS OF THE FA THIS EVE DUE TO LESSER SUNSHINE AND
INSTABILITY. WE WILL KEEP ENHANCED WORDING FOR GUSTY WINDS...SMALL
HAIL AND HEAVY DOWNPOURS. LASTLY...WE INCORPORATED LATEST OBSVD
TEMPS INTO THE HRLY TEMP FCST LEADING UP TO UNMODIFIED FCST HI
TEMPS THIS AFTN.
920 AM UPDATE: IN THIS UPDATE...WE ADDED ENHANCED TSTM WORDING FOR
GUSTY WINDS...SMALL HAIL AND HEAVY DOWNPOURS FOR LATER THIS AFTN
INTO THE EVE BASED ON SPC GUIDANCE...SPCLY FOR THE NW TWO THIRDS
OF THE FA. OTHER THAN INCORPORATING LATEST OBSVD TEMPS INTO THE
HRLY TEMP FCST LEADING UP TO FCST HI TEMPS THIS AFTN...NO OTHER
CHGS ATTM.
550 AM UPDATE: PATCHY SHOWERS OVER EASTERN PARTS OF THE STATE ARE
LIFTING NORTHEAST AND AWAY. RAIN WILL LIKELY END FOR A WHILE IN
THE EAST. MEANWHILE MORE CONVECTIVE SHOWERS ARE BEGINNING TO PUSH
INTO WESTERN AREAS IN RESPONSE TO THE UPPER LOW BUILDING OVER.
FORECAST WAS UPDATED TO REFLECT ONE AREA OF SHOWERS MOVING AWAY
AND THE NEXT AREA MOVING IN DURING THE COURSE OF THE DAY.
ORGNL DISC: A TROUGH OF LOW PRESSURE APPROACHING FROM THE WEST
WILL CONTINUE PULLING MOISTURE NORTH ACROSS THE AREA THIS MORNING
AS SHOWERS SPREAD IN FROM THE SOUTHWEST. SHOWERS ASSOCIATED WITH
THIS TROUGH WILL LIKELY COME IN TWO PHASES TODAY. AN INITIAL BATCH
OF SHOWERS WILL COME THROUGH THIS MORNING AS THE TROUGH DRAWS
MOISTURE NORTH ACROSS THE REGION. THERE MAY BE A BREAK AROUND
MIDDAY AS A BIT OF DRIER AIR PULLS IN ALOFT AND SKIES BRIGHTEN A
BIT. THEN LATER TODAY AS THE UPPER TROUGH MOVES IN AND HEIGHTS
LOWER THE ATMOSPHERE WILL BECOME UNSTABLE. CAPES ARE PROGGED TO
REACH AROUND 1000 J/KG LATE THIS AFTERNOON. MESOSCALE MODELS ARE
SHOWING A LINE OF SHOWERS AND THUNDERSTORMS MOVING INTO WESTERN
AREAS EARLY THIS AFTERNOON. SHOWERS AND THUNDERSTORMS WILL THEN BE
LIKELY THIS AFTERNOON ACROSS CENTRAL AND NORTHERN AREAS AS A WEAK
SURFACE TROUGH MOVES IN AND HEIGHTS CONTINUE TO FALL ALOFT WITH
THE APPROACH OF THE UPPER TROUGH. SOUNDING FORECASTS INDICATE THAT
UNSTABLE CONDITIONS LAST WELL INTO THIS EVENING AS HEIGHTS
CONTINUE TO FALL. SOME THUNDERSTORMS MAY CONTINUE TO BE SCATTERED
AROUND WELL INTO THE EVENING TONIGHT. SHOWERS ARE THEN EXPECTED TO
TAPER OFF TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AN UPPER LOW WILL MOVE NORTH OF THE REGION TUESDAY...WHILE A
SECONDARY SURFACE COLD FRONT/TROF CROSS THE FORECAST AREA. EXPECT
MOSTLY CLOUDY SKIES ALONG WITH A CHANCE OF SHOWERS/THUNDERSTORMS
ACROSS NORTHERN AREAS TUESDAY...WITH PARTLY SUNNY SKIES ALONG WITH
A CHANCE OF SHOWERS ACROSS CENTRAL AND DOWNEAST AREAS. THE UPPER
LOW WILL MOVE NORTHEAST TUESDAY NIGHT WHILE SURFACE HIGH PRESSURE
BEGINS TO BUILD EAST. AN EVENING SHOWER IS POSSIBLE ACROSS
NORTHERN AREAS EARLY TUESDAY NIGHT...WITH DECREASING CLOUDS
OVERNIGHT. PARTLY CLOUDY/MOSTLY CLEAR SKIES ARE EXPECTED ACROSS
CENTRAL AND DOWNEAST PORTIONS OF THE FORECAST AREA TUESDAY NIGHT.
SURFACE HIGH PRESSURE WILL CROSS THE REGION WEDNESDAY THROUGH
WEDNESDAY NIGHT. AN UPPER DISTURBANCE CROSSING THE REGION
WEDNESDAY WILL BRING PARTLY SUNNY SKIES TO THE FORECAST AREA.
PARTLY CLOUDY/MOSTLY CLEAR SKIES ARE EXPECTED ACROSS NORTHERN
AREAS WEDNESDAY NIGHT...WITH MOSTLY CLEAR SKIES ACROSS
CENTRAL/DOWNEAST AREAS. TEMPERATURES WILL BE AT SLIGHTLY BELOW
NORMAL LEVELS TUESDAY...WITH NEAR NORMAL LEVEL TEMPERATURES
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION EARLY THURSDAY WITH A
WARM FRONT APPROACHING LATE. PARTLY SUNNY SKIES ARE EXPECTED
ACROSS THE REGION THURSDAY...WITH MOSTLY CLOUDY SKIES AND A
CHANCE OF SHOWERS THURSDAY NIGHT. A COLD/OCCLUDED FRONT WILL CROSS
THE REGION FRIDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
OTHER COLD FRONTS/TROFS WILL CROSS THE REGION BOTH SATURDAY AND
SUNDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
FORECAST AREA...WITH THE BETTER CHANCES ACROSS NORTHERN AREAS.
TEMPERATURES WILL BE AT NEAR NORMAL LEVELS THURSDAY...WITH
SLIGHTLY BELOW NORMAL LEVEL TEMPERATURES FRIDAY THROUGH SUNDAY.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
NEAR TERM: GENERALLY IFR TO OCCASIONALLY MVFR CONDITIONS IN
SHOWERS AND LOW CLOUDS ARE EXPECTED TODAY AND TONIGHT.
SHORT TERM: VARIABLE CONDITIONS ARE POSSIBLE WITH ANY
SHOWERS/THUNDERSTORMS TUESDAY INTO TUESDAY EVENING.
OTHERWISE...GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE
REGION TUESDAY THROUGH MUCH OF THURSDAY. VARIABLE CONDITIONS ARE
POSSIBLE WITH SHOWERS/THUNDERSTORMS AGAIN FRIDAY.
&&
.MARINE...
NEAR TERM: WINDS ARE EXPECTED TO BE LIGHT TODAY AND TONIGHT. FOG
WILL LIKELY LIMIT VISIBILITIES OVER THE WATERS EARLY TODAY.
SHORT TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS TUESDAY THROUGH FRIDAY. VISIBILITIES COULD BE
REDUCED IN SHOWERS THURSDAY NIGHT INTO FRIDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORCROSS
LONG TERM...NORCROSS
AVIATION...VJN/NORCROSS
MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
345 PM EDT MON JUL 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 251 PM EDT MON JUL 29 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE WRN GRT LKS BTWN SLOWLY DEPARTING CUTOFF LO JUST S OF
JAMES BAY AND AN UPR RDG OVER MN. THE ARRIVAL OF SFC HI PRES/ACYC
FLOW AND DRIER AIRMASS SHOWN ON THE 12Z INL RAOB ARE BRINGING A
MOSUNNY DAY TO THE CWA. LOOKING UPSTREAM...A SHRTWV IS MOVING INTO
THE NRN PLAINS IN THE WSW FLOW ALF BTWN THE UPR RDG OVER MN AND A
TROF OVER SW CANADA. THERE ARE SOME SHRA/TS ASSOCIATED WITH THIS
FEATURE...AND SOME CLDS WELL IN ADVANCE OF THE SHRA ARE SPILLING
INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE MIN TEMPS TNGT AND THE CHC
FOR SOME SHRA ON TUE.
TNGT...UPR RDG AXIS IS PROGGED TO DRIFT W-E OVER UPR MI TNGT.
FOLLOWING THE PASSAGE OF THE UPR RDG...SOME MSTR IN ADVANCE OF
SHRTWV MOVING INTO MN IS FCST TO SPREAD INTO THE WRN CWA. IN CONCERT
WITH INCRSG WSW FLOW AT H925 ON THE BACK SIDE OF RETREATING SFC HI
PRES TO THE E...THE FALL OF TEMP OVER THE NW PORTIONS OF THE CWA
SHOULD BE HELD IN CHECK A BIT. THE BEST CHC FOR MIN TEMPS FALLING
FARTHER INTO THE 40S WL BE OVER THE INTERIOR SCENTRAL AND E...WHERE
THE CLDS WL ARRIVE LATEST CLOSER TO THE RETREATING HI.
TUE...A NUMBER OF MODELS GENERATE SOME MAINLY LGT PCPN OVER UPR MI
AS SHRTWV DRIFTS TO THE E AND INTERACTS WITH MODEST RETURN OF
SOMEWHAT HIER H85 THETA E. SUSPECT THE BEST CHC FOR SOME SHRA WL BE
IN THE AFTN WITH DAYTIME HEATING AND SOME LLVL CNVGC ON LK BREEZE
BNDRYS. SYNOPTIC SCALE SW FLOW SHOULD LIMIT INLAND PENETRATION OF
BREEZE OFF LK SUP. SINCE MODEL FCST SDNGS CONTINUE TO EXHIBIT
RELATIVELY WARM MID LVLS TEMPS/SOME CAPPING AOA H7/MARGINAL MID LVL
LAPSE RATES...WENT NO HIER THAN SCHC POPS AND KEPT OUT THE MENTION
OF TS FOR NOW WITH LIMITED INSTABILITY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 344 PM EDT MON JUL 29 2013
WE WILL START THIS LONG TERM PERIOD OUT WITH WESTERLY FLOW AT
500MB...WITH A RIDGE STUCK ACROSS THE SOUTHERN U.S. AND THE NEXT OF
A SERIES OF LOWS SET UP ACROSS MANITOBA.
THE 500MB LOW OVER MANITOBA WILL SHIFT ACROSS WESTERN AND CENTRAL
ONTARIO WEDNESDAY AS THE SFC RIDGE OVERHEAD EXITS TO THE SE. 850MB
TEMPS IN DECENT WAA BEHIND THE RIDGE SHOULD RISE TO AROUND 13C
BEFORE COLD FRONT SWEEPS IN FROM THE WNW DURING THE AFTERNOON AND
EARLY EVENING HOURS. TIMING LOOKS TO BE SIMILAR WITH THE AVAILABLE
MODEL GUIDANCE...WITH SHOWERS AND THUNDERSTORMS REMAINING MAINLY TO
OUR W OR OVER LAKE SUPERIOR THROUGH 12Z WEDNESDAY...AROUND 0.25IN
OVER THE W TIER OF COUNTIES BY 18Z...AND CENTRAL AND E DURING THE
MID TO LATE AFTERNOON HOURS. THERE ARE A COUPLE OF OUTLIERS. THE
29/12Z REGIONAL WRF AND CANADIAN RUNS WERE EITHER TOO STRONG OR TOO
WEAK WITH THE SHORTWAVES ROTATING THROUGH...AS THE 500MB TROUGH
BEGINS TO SWING INTO UPPER MI ON WEDNESDAY. VARIABLE PRECIPITATION
OUTPUTS OF NEARLY NOTHING TO AROUND AN INCH WERE THE RESULT. THE WRF
AND CANADIAN RUNS WERE EXCLUDED FROM MUCH OF THIS FCST...GIVEN THE
LOWER CONFIDENCE IN EITHER SOLUTION.
EXPECT THE COLD FRONT TO BE OVER FAR EASTERN UPPER MI BY 06Z
THURSDAY...WITH COOLER AIR FILTERING IN FROM THE NW ONCE AGAIN.
850MB TEMPS SHOULD FALL TO AROUND 8C BY DAYBREAK THURSDAY...WITH
LOWS NEAR 50F OVER THE W HALF OF UPPER MI WITH W WINDS HOVERING NEAR
10KTS.
NO REAL WARM UP IS EXPECTED FOR THURSDAY THROUGH THE UPCOMING
WEEKEND AS A SERIES OF DISTURBANCES SWINGING IN FROM THE NW HELP
KEEP THEM IN CHECK. THERE COULD BE SOME POP UP AFTERNOON SHOWERS OR
EVEN A THUNDERSTORM THURSDAY AFTERNOON INLAND FROM LAKE
SUPERIOR...AS ANOTHER SHORTWAVE ROTATES AROUND THE MAIN 500MB LOW
STUCK NEAR AND ACROSS HUDSON BAY. A SLIGHTLY MORE SIGNIFICANT SFC
TROUGH/500MB SHORTWAVE WILL SLIDE ACROSS FRIDAY AFTERNOON...WITH
ADDITIONAL CLOUD COVER...SHOWERS...AND INLAND POP UP THUNDERSTORMS.
YET ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE SATURDAY...ALTHOUGH
LIKELY FARTHER EAST AS THE ENTIRE SYSTEM SHIFTS EASTWARD AND THE SFC
RIDGE BEGINS TO SHIFT IN. EXPECT DRY WEATHER SUNDAY AS THE SFC HIGH
PUSHES OVERHEAD...EVEN THROUGH NW FLOW LINGERS ALOFT. WITH THE
29/12Z ECMWF SHOWING 850MB TEMPS ON AROUND 7C AND LIGHT N
WINDS...60S AND LOW 70S STILL LOOK REASONABLE FOR HIGH TEMPS. AS FOR
DAY 7/MONDAY...THE SFC HIGH DOES NOT LOOK TO MOVE MUCH...BUT A WAVE
SLIDING THROUGH THE NW FLOW COULD BRING A PARTLY CLOUDY SKY TO THE W
WITH A FEW SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 131 PM EDT MON JUL 29 2013
ALTHOUGH SOME MID CLDS AND PERHAPS A FEW -SHRA WL SPILL INTO UPR MI
LATER TNGT/TUE IN ADVANCE OF A DISTURBANCE MOVING E INTO MN...EXPECT
VFR CONDITIONS TO PREDOMINATE AT ALL 3 TAF SITES WITH LINGERING LLVL
DRY AIR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 251 PM EDT MON JUL 29 2013
EXPECT WINDS NO HIER THAN 20 KTS THIS FORECAST PERIOD WITH WEAK PRES
GRADIENT DOMINATING THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
252 PM EDT MON JUL 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 251 PM EDT MON JUL 29 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE WRN GRT LKS BTWN SLOWLY DEPARTING CUTOFF LO JUST S OF
JAMES BAY AND AN UPR RDG OVER MN. THE ARRIVAL OF SFC HI PRES/ACYC
FLOW AND DRIER AIRMASS SHOWN ON THE 12Z INL RAOB ARE BRINGING A
MOSUNNY DAY TO THE CWA. LOOKING UPSTREAM...A SHRTWV IS MOVING INTO
THE NRN PLAINS IN THE WSW FLOW ALF BTWN THE UPR RDG OVER MN AND A
TROF OVER SW CANADA. THERE ARE SOME SHRA/TS ASSOCIATED WITH THIS
FEATURE...AND SOME CLDS WELL IN ADVANCE OF THE SHRA ARE SPILLING
INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE MIN TEMPS TNGT AND THE CHC
FOR SOME SHRA ON TUE.
TNGT...UPR RDG AXIS IS PROGGED TO DRIFT W-E OVER UPR MI TNGT.
FOLLOWING THE PASSAGE OF THE UPR RDG...SOME MSTR IN ADVANCE OF
SHRTWV MOVING INTO MN IS FCST TO SPREAD INTO THE WRN CWA. IN CONCERT
WITH INCRSG WSW FLOW AT H925 ON THE BACK SIDE OF RETREATING SFC HI
PRES TO THE E...THE FALL OF TEMP OVER THE NW PORTIONS OF THE CWA
SHOULD BE HELD IN CHECK A BIT. THE BEST CHC FOR MIN TEMPS FALLING
FARTHER INTO THE 40S WL BE OVER THE INTERIOR SCENTRAL AND E...WHERE
THE CLDS WL ARRIVE LATEST CLOSER TO THE RETREATING HI.
TUE...A NUMBER OF MODELS GENERATE SOME MAINLY LGT PCPN OVER UPR MI
AS SHRTWV DRIFTS TO THE E AND INTERACTS WITH MODEST RETURN OF
SOMEWHAT HIER H85 THETA E. SUSPECT THE BEST CHC FOR SOME SHRA WL BE
IN THE AFTN WITH DAYTIME HEATING AND SOME LLVL CNVGC ON LK BREEZE
BNDRYS. SYNOPTIC SCALE SW FLOW SHOULD LIMIT INLAND PENETRATION OF
BREEZE OFF LK SUP. SINCE MODEL FCST SDNGS CONTINUE TO EXHIBIT
RELATIVELY WARM MID LVLS TEMPS/SOME CAPPING AOA H7/MARGINAL MID LVL
LAPSE RATES...WENT NO HIER THAN SCHC POPS AND KEPT OUT THE MENTION
OF TS FOR NOW WITH LIMITED INSTABILITY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 342 AM EDT MON JUL 29 2013
LITTLE CHANGE TO THE LONG TERM FORECAST OVER THE LAST 24 HOURS WITH
THE PRIMARY WEATHER MAKER FOR THE PERIOD BEING A COLD FRONT MOVING
THROUGH ON WEDNESDAY.
UPPER MICHIGAN WILL BE UNDER AN SURFACE RIDGE AND EXITTING WEAK
UPPER RIDGE ON TUESDAY MORNING. AFTER A COOL START...TEMPERATURES
SHOULD WARM UP QUICKLY UNDER INCREASING HIGH CLOUDS FROM THE WEST
AND HIGHS WILL BE IN THE 70S. WITH A SHORTWAVE MOVING ACROSS LAKE
SUPERIOR DURING THE MORNING AND FIRST PART OF THE
AFTERNOON...QUESTION BECOMES WHETHER THERE WILL BE ENOUGH MOISTURE
FOR SHOWER DEVELOPMENT. MODELS HAVE TRENDED UP MOISTURE OVER THE
LAST 24 HOURS AND INDICATE MORE DIURNAL CLOUD DEVELOPMENT OVER THE
CENTRAL AND EAST...ESPECIALLY NEAR THE WEAK LAKE BREEZE CONVERGENCE
AROUND LAKE SUPERIOR. WITH THIS INCREASE IN MOISTURE...MORE MODELS
ARE HINTING AT LIGHT SHOWER DEVELOPMENT (ESPECIALLY IN THE HI-RES
MODELS). INSTABILITY IS FAIRLY MARGINAL AND WITH A CAP AROUND
10KFT...WOULDN/T EXPECT THE CLOUDS TO BUILD TOO MUCH...BUT FELT
THERE WAS ENOUGH INDICATION OF SOME SHOWERS TO MENTION A SLIGHT
CHANCE BY THE LAKE BREEZE IN NORTH CENTRAL AND EAST. KEPT THUNDER
OUT OF THE FORECAST SINCE CLOUD DEPTH IS SHALLOW AND THE CAP WILL
KEEP THE CLOUD ABOVE FREEZING.
PRECIPITATION CHANCES WILL REMAIN LIMITED ON TUESDAY NIGHT UNTIL
THE STRONG SHORTWAVE ARRIVES OVER THE WESTERN U.P. LATE WEDNESDAY
MORNING AND MOVES ACROSS THE REST OF THE U.P. ON WEDNESDAY
AFTERNOON AND EVENING. WITH GROWING CONFIDENCE IN PRECIPITATION
OCCURRING...WILL TREND VALUES UP TO LIKELY OVER PORTIONS OF THE CWA
AND TRY TO PROVIDE BETTER TIMING ON THE SHOWERS MOVING THROUGH
FROM WEST TO EAST. WILL CAP THUNDER AT CHANCE PROBS SINCE MLCAPE IS
BELOW 600J/KG OVER THE ENTIRE AREA. MODELS ARE ALL OVER THE PLACE ON
THE EFFECT SHEAR FOR THE THUNDERSTORMS /20-40KTS/...BUT WITH THE
MARGINAL INSTABILITY...DON/T THINK THERE IS MUCH SEVERE CONCERN.
WEAK INSTABILITY IN AN AREA WHERE THERE WILL LIKELY BE A BROAD AREA
OF SHOWERS DOESN/T LEND ITSELF TO SEVERE WEATHER...ESPECIALLY IF
CLOUDS AND RAIN SPREAD NORTHEAST AHEAD OF THE FRONT UNDER THE WARM
AIR ADVECTION. OUT OF THE ENTIRE AREA...THE BEST OPPORTUNITY FOR
STRONGER THUNDERSTORMS WOULD BE OVER THE SOUTH CENTRAL...WHERE THE
INGREDIENTS OVERLAP THE BEST AND FRONT TIMING TOWARDS PEAK HEATING
OCCURS.
THROUGH JULY 28TH...OUR OFFICE IS UP TO THE 8TH WETTEST JULY
ON RECORD. THE ADDITIONAL RAIN ON WEDNESDAY...LIKELY A QUARTER OF AN
INCH OR MORE...SHOULD EASILY PUSH THIS JULY INTO THE TOP 5 WETTEST
JULY/S ON RECORD. THE FRONT AND DEEPER MOISTURE WILL QUICKLY DEPART
FROM WEST TO EAST WEDNESDAY EVENING AND EARLY OVERNIGHT HOURS AND
WILL CONTINUE THE TREND TOWARDS DRY AND CLEARING.
BEHIND THE SHORTWAVE...THE AREA WILL BE ON THE SOUTHWEST SIDE OF THE
UPPER TROUGH ROTATING IN NORTHERN ONTARIO AND SLOWLY MOVING EAST
INTO QUEBEC THIS WEEKEND. MOST LOCATIONS WILL BE DRY ON
THURSDAY...BUT MOISTURE WRAPPING AROUND THE UPPER LOW WILL LEAD TO
PARTLY CLOUDY SKIES OVER PORTIONS OF THE AREA WITH DIURNAL
HEATING...ESPECIALLY OVER THE EAST. ANOTHER SHORTWAVE DOES ROTATE
AROUND THE UPPER LOW ON THURSDAY AFTERNOON...SO DID MENTION SOME
SHOWERS NEAR LAKE MICHIGAN WHERE THERE WILL BE THE GREATEST
INSTABILITY.
FRIDAY INTO THE WEEKEND WILL BE DOMINATED BY THE NORTHWEST FLOW
ALOFT...ALTHOUGH THE AREA WILL BE ON THE EDGE OF THE WEATHER FROM
THE UPPER LOW AND THE OTHER WAVES MOVING THROUGH THE CENTRAL PLAINS
AND LOWER GREAT LAKES. EXPECT THIS TO PRODUCE MAINLY DRY
CONDITIONS...ALTHOUGH AN OCCASIONAL SHOWER CAN/T BE COMPLETELY
RULED OUT AS SHORTWAVES ROTATE AROUND THE UPPER LOW. A HIGH PRESSURE
RIDGE WILL SLOWLY NOSE INTO THE SOUTHWEST HALF OF THE CWA SATURDAY
AND SUNDAY FROM A HIGH CENTERED NEAR LAKE WINNIPEG. TEMPERATURES
THURSDAY THROUGH THE WEEKEND WILL BE A LITTLE BELOW NORMAL...WITH
HIGHS IN THE MID 60S TO LOWER 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 131 PM EDT MON JUL 29 2013
ALTHOUGH SOME MID CLDS AND PERHAPS A FEW -SHRA WL SPILL INTO UPR MI
LATER TNGT/TUE IN ADVANCE OF A DISTURBANCE MOVING E INTO MN...EXPECT
VFR CONDITIONS TO PREDOMINATE AT ALL 3 TAF SITES WITH LINGERING LLVL
DRY AIR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 251 PM EDT MON JUL 29 2013
EXPECT WINDS NO HIER THAN 20 KTS THIS FORECAST PERIOD WITH WEAK PRES
GRADIENT DOMINATING THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1249 PM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 29 2013
TODAY...MULTIPLE MODES OF ATMOSPHERIC UNREST ARE OPERATING ACROSS
THE FCST AREA THIS MORNING AND ARE EXPECTED TO CONTINUE THROUGH
THIS EVENING. STRATUS...FOG...DRIZZLE...SHOWERS PRODUCING DECENT
RAINFALL IN A WARM CLOUD PROCESS ARE OPERATING ACROSS SWRN NEB
THROUGH NCNTL NEBRASKA THIS MORNING. THIS AREA OF WEATHER IS
EXPECTED TO SHIFT EAST THIS MORNING AND COVER AREAS ALONG AND
EAST OF HIGHWAY 183 THIS AFTERNOON. IT IS BELIEVED THAT THE
SHOWERS AND DRIZZLE/FOG SHOULD EXIT BY 18Z AS THIS IS BEING
DRIVEN BY MOISTURE TRANSPORT AT THE 315K SFC AND ACCORDING TO THE
RAP...THIS TRANSPORT SHOULD WEAKEN THIS MORNING.
THE ONGOING MCS ACROSS NWRN NEB IS EXPECTED TO DECAY BY 12Z AS
RADAR SUGGESTS AN OCCLUSION PROCESS IS UNDERWAY ACROSS FAR SWRN
SD. ALSO THE RAP SHOWS MOISTURE TRANSPORT ON THE 315K SFC WILL
WEAKEN.
TEMPERATURES TODAY RANGE FROM 60S ACROSS THE EAST UNDER A BLANKET
OF STRATUS TO 80S ACROSS WRN NEB WHERE IT IS BELIEVED SKIES WILL
CLEAR. THE RAP MODEL SHOWS 750MB CAPE INCREASING TO AROUND 1000
J/KG AND THE NAM THEN SHOWS THE ATM DESTABILIZING ACROSS SWRN AND
WRN NEB LATE THIS AFTERNOON. DOWN DRAFT CAPE NEAR 1000 J/KG COULD
SUPPORT A FEW STORMS WITH GUSTY WINDS...MAINLY THIS EVENING AS
THE STORMS ARE EXPECTED TO ORIGINATE ACROSS THE CYS DIVIDE AND
PARTS OF NERN COLO AND MOVE INTO THE FCST LATE THIS AFTN OR EARLY
EVENING.
TONIGHT...SCATTERED TSTMS ARE EXPECTED TO REMAIN WEST OF HIGHWAY
83 AND MAINLY ALONG AND WEST OF HIGHWAY 61. THE NAM SHOWS THESE
STORMS WEAKENING/DISSIPATING BY 03Z. A WEAK MOSTLY OUTFLOW DRIVEN
COLD FRONT IS EXPECTED TO DRAPE FROM KOGA TO KVTN IN THE WAKE OF
THE STORMS AND LOW LEVEL MOISTURE EAST OF THE FRONT APPEARS
LIKELY TO PRODUCE ANOTHER ROUND OF STRATUS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 29 2013
UPPER LEVEL RIDGE IS GENERALLY ACROSS THE 4 CORNERS REGION...AND
WILL BUILD EAST TOWARDS THE WEEKEND. MEANWHILE AN UPPER LEVEL
TROUGH/LOW WILL PUSH ACROSS CANADA MID WEEK...WITH THE LOW
REACHING THE SRN PART OF HUDSON BAY BY THE WEEKEND. OVER THE HIGH
PLAINS FLOW WILL BE NORTHWEST THROUGH THE WEEK...WITH A TRANSITION
TO MORE ZONAL BY WEEKEND.
AT THE SFC..COOL CANADIAN HIGH PRESSURE ACROSS THE CENTRAL PLAINS
EARLY...WILL SLOWLY PUSH EAST...WITH A WARM UP EXPECTED. THEN A
COLD FRONT WILL PUSH ACROSS THE AREA WEDNESDAY WITH ANOTHER COOL
DOWN TO END THE WEEK. HIGHS SHOULD RETURN TO THE 80S...NEAR OR
SLIGHTLY BELOW SEASONAL BY MID WEEK...AHEAD OF THE FRONT. BY FRIDAY
AS THE COOLER HIGH PRESSURE PUSHES ACROSS THE CENTRAL
PLAINS...TEMPS TO COOL BACK INTO THE UPPER 70S TO LOWER 80S. AFTER
THE EXTENT OF THE LATEST COOL DOWN...WILL HAVE TO MONITOR CLOSELY
THE COOLER AIR AS A TREND DOWN IN TEMPS IS POSSIBLE.
MODELS IN AGREEMENT WITH AN ACTIVE PATTERN TO CONTINUE THROUGH THE
WEEK WITH SEVERAL DISTURBANCES TO RIDE THE PERIPHERY OF THE RIDGE
AND ACROSS THE AREA. MOISTURE REMAINS DECENT WITH DEW PTS IN THE
UPPER 50S TO LOWER AND MID 60S. WITH EACH QUICK MOVING WAVE EXPECT
SHOWERS AND A FEW THUNDERSTORMS TO BE POSSIBLE.
ON WEDNESDAY...WITH THE PASSAGE OF THE COLD FRONT AND COOLER AIR
ALOFT...THERE COULD BE A FEW STRONG THUNDERSTORMS. TIMING AND
PLACEMENT OF THE BEST INSTABILITY STILL IN QUESTION...AND WILL BE
WATCH OVER THE NEXT COUPLE OF DAYS. THE REST OF THE WEEK WILL
CONTINUE TO SEE A CHANCE FOR SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH EACH PASSING WAVE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1249 PM CDT MON JUL 29 2013
THE 18Z TAF ISSUANCE FOR KLBF AND KVTN. EXPECTING THE IFR TO
MVFR CEILINGS TO LIFT FROM WEST TO EAST TODAY...WITH VFR ANTICIPATED
AT KLBF AFTER 21Z. AT KVTN...CEILINGS ARE BEGINNING TO IMPROVE
EARLY THIS AFTERNOON...SUCH THAT NO RESTRICTIONS ARE ANTICIPATED
WITHIN THE NEXT HOUR OR SO. FOR THE OVERNIGHT...NEAR TERM MODEL
GUIDANCE SUGGESTS THE LOWERED CEILINGS WILL RETURN WEST...WITH A
REPEAT OF IFR OR POSSIBLY LOWER FOR KLBF IN BOTH CEILING AND
VISIBILITY. THERE/S A BIT MORE UNCERTAINTY WITH THE NORTHWARD
EXTENT OF THE STRATUS OVERNIGHT...THUS WILL BE LESS PESSIMISTIC IN
CEILING AND VISIBILITY FORECASTS FOR KVTN. OTHERWISE STORMS ARE
POSSIBLE ACROSS THE EASTERN PANHANDLE THIS EVENING...WITH ADDITIONAL
CONVECTION POSSIBLE ACROSS NW NEBRASKA AFTER 15Z TOMORROW. STRONG
WIND GUSTS AND HAIL WOULD BE POSSIBLE WITH ANY STORM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
322 PM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE OFFSHORE EARLY TUESDAY AND LINGER NEAR
THE COAST INTO WEDNESDAY BEFORE DISSIPATING. HIGH PRESSURE OFFSHORE
WILL DOMINATE LATE IN THE WEEK. ANOTHER COLD FRONT WILL APPROACH FROM
THE NORTHWEST THIS WEEK BEFORE STALLING NEAR OR JUST NORTH OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 315 PM MONDAY...THUNDERSTORMS HAVE BLOSSOMED THIS AFTERNOON
ACROSS THE REGION IN AREA OF HIGH INSTABILITY WITH SURFACE-BASED
CAPE VALUES IN EXCESS OF 4000 J/KG AND STRONG MOISTURE CONVERGENCE
AHEAD OF COLD FRONTAL BOUNDARY. THE STORMS HAVE BEEN PROLIFIC
LIGHTNING PRODUCERS AND HAVE PRODUCED LOCALIZED HEAVY RAINFALL
AMOUNTS. GOOD AGREEMENT AMONGST THE VARIOUS 4 KM WRF MODELS...THE
HRRR AND THE RAP MODELS THAT THE PRECIPITATION SHOULD DISSIPATE
SHORTLY AFTER DARK WITH LOSS OF HEATING. WILL CARRY A LIKELY POP
ACROSS ROUGHLY THE SOUTHEASTERN THIRD OF THE CWA THROUGH 00Z WITH
HIGH CHANCE ACROSS THE HIGHWAY 17 CORRIDOR AND JUST SLIGHT CHANCE
FAR WEST. WITH SOME SLIGHTLY LOWER DEWPOINTS WORKING INTO THE
REGION...THE FAR NORTHWESTERN COUNTIES MAY NOT SEE ANY
PRECIPITATION THIS EVENING. AFTER DARK...HAVE JUST CHC POPS ALONG
AND EAST OF HIGHWAY 17 WITH NO POPS TO THE WEST. LOW TEMPERATURES
WILL SHOW A SIMILAR GRADIENT WITH UPPER 60S WEST OF HIGHWAY
17...BUT LOWER TO MID 70S TO THE EAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
AS OF 315 PM MONDAY...THE MID-LEVEL TROUGH AXIS SHOULD BE OFFSHORE
BY EARLY TUESDAY ALONG WITH MOST OF THE DEEP MOISTURE AS THE
FRONTAL BOUNDARY MOVES JUST SOUTH OF OUR COAST AND LIKELY STALLS.
THINK ROUGHLY THE NORTHERN TWO-THIRDS OF OUR CWA WILL BE DRY ON
TUESDAY AS UPPER HEIGHTS BUILD IN A ZONAL FLOW ALOFT. DID HANG ON
TO 20 TO 30 PCT POPS ALONG THE SOUTHERN THIRD OF THE AREA TOMORROW
GIVEN THE CLOSE PROXIMITY OF THE FRONT. MAXIMUM TEMPERATURES
SHOULD BE IN THE MIDDLE TO UPPER 80S AREA-WIDE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 245 PM MON...USED A CONSENSUS BLEND THROUGH THE EXTENDED
PERIOD. UPPER PATTERN WILL FEATURE AND AMPLIFYING TROF ALONG THE
EASTERN SEABOARD THROUGH FRIDAY NIGHT. THE TROF WILL SLOWLY LIFT
OUT THIS WEEKEND WITH A ZONAL FLOW RETURNING FOR EARLY NEXT WEEK.
AT THE SURFACE...STATIONARY BOUNDARY TO THE SOUTH TUESDAY NIGHT
WILL LIFT NORTH WEDNESDAY INTO WEDNESDAY NIGHT. A COLD FRONT WILL
SLOWLY APPROACH FROM THE NORTHWEST THIS WEEKEND. HIGHEST RAIN
CHANCES WILL BE IN THE MIDWEEK PERIOD WITH THE WARM FRONT LIFTING
THROUGH AND GOOD LOW LEVEL THETA-E RIDGE SET UP ACROSS THE AREA.
RAIN CHANCES WILL NOT BE AS HIGH FROM LATE WEEK INTO THE WEEKEND
AS THETA-E RIDGE SHIFTS TO THE SOUTH.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 1230 PM MONDAY...STRATUS HAVE BEEN SLOW TO DISSIPATE AT THE
TAF SITES THIS MORNING...BUT HAVE FINALLY DONE SO BY NOON. EXPECT
LARGELY VFR CONDITIONS OUTSIDE OF SCATTERED SHOWERS AND TSTMS
THROUGH THE AFTERNOON AND EVENING...ALTHOUGH HEAVY RAINFALL WILL
REDUCE VSBYS AND CEILINGS TO MVFR AND PERHAPS BRIEFLY IFR AT
TIMES. BOTH PERSISTENCE AND THE 12Z NUMERICAL GUIDANCE INDICATES A
GOOD POSSIBILITY OF FOG LATE TONIGHT...GIVEN HIGH BOUNDARY LAYER
RH AND A WET GROUND IN SPOTS AND WILL FORECAST AT LEAST MVFR FOG
TOWARD TUESDAY MORNING.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 245 PM MON...GENERALLY VFR EXCEPT IN SCATTERED SHOWERS AND
THUNDERSTORMS EACH DAY. LIGHT EAST WINDS WEDNESDAY. SOUTHWEST
THURSDAY THROUGH SATURDAY.
&&
.MARINE...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 325 PM MONDAY...A COLD FRONT IS DRAPED ACROSS THE NORTHERN
TIER OF THE CWA AND WINDS HAVE GONE MORE WNW/NW OVER THE ALBEMARLE
SOUND AND FAR NORTH WHILE OTHER AREAS REMAIN SOUTH. WINDS SHOULD
GRADUALLY VEER TO W/NW LATER TONIGHT AND HAVE INDICATED THAT TREND
IN THE CURRENT MARINE FORECAST. WIND SPEEDS SHOULD REMAIN AOB 15
KNOTS WITH SEAS 2 TO 4 FEET...OUTSIDE OF THIS EVENING`S
CONVECTION. N/NE WINDS EARLY TUESDAY WILL GRADUALLY BECOME MORE
SE/S LATE TUESDAY AS THE FRONT TO THE SOUTH MEANDERS SLOWLY NORTH.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 245 PM MON...FRONTAL BOUNDARY WILL BE JUST SOUTH OF THE
WATERS TUESDAY NIGHT...BUT WILL THEN LIFT NORTH OF THE AREA
WEDNESDAY AND WEDNESDAY NIGHT. A COLD FRONT WILL SLOWLY DRIFT IN
FROM THE NORTHWEST THIS WEEKEND. LIGHT EAST WINDS FORECAST FOR
WEDNESDAY AS THE WARM FRONT LIFTS THROUGH. SOUTHWEST FLOW SETS UP
BEGINNING THURSDAY WITH THE WARM FRONT TO THE NORTH AND THE COLD
FRONT APPROACHING FROM THE NORTHWEST. THE PRESSURE GRADIENT
TIGHTENS UP AS WELL THURSDAY AND FRIDAY WITH 15-20 KNOTS OVER THE
COASTAL WATERS SOUTH OF OREGON INLET AND 10-15 KNOTS ELSEWHERE.
SMALL CRAFT SEAS FORECAST FOR THE OREGON INLET TO OCRACOKE WATERS
OF 4-6 FEET. THE GRADIENT WILL RELAX AS THE FRONT APPROACHES THE
COAST ON SATURDAY WITH WINDS AND SEAS SUBSIDING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...HSA
AVIATION...CTC/HSA
MARINE...CTC/HSA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
338 PM CDT MON JUL 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 338 PM CDT MON JUL 29 2013
FORECAST CHALLENGES INCLUDE CONVECTIVE CHANCES TONIGHT THROUGH
TOMORROW NIGHT. GFS/NAM/ECMWF/GEM SYNOPTIC FIELDS IN GOOD OVERALL
AGREEMENT...BUT DIFFER SOMEWHAT WITH THE MESOSCALE DETAILS. WILL
USE THE RAP FOR THE ONGOING CONVECTION ACROSS CENTRAL ND THIS
EVENING AND TONIGHT...SHIFTING TO A MODEL BLEND FOR THE REMAINDER
OF THE SHORT-TERM.
20 UTC REGIONAL RADARS SHOW THE SHOWERS ACROSS NORTHEAST SD HAVE
BARELY MOVED INTO THE SOUTHERN VALLEY WITH PERHAPS A FEW SPRINKLES
FALLING ACROSS THE LAKES COUNTRY OF WEST CENTRAL MN. WILL KEEP 20
TO 30 POPS IN THESE AREAS THROUGH THE EARLY EVENING AFTER WHICH ANY
REMAINING ACTIVITY SHOULD DISSIPATE. IN ADDITION...THE ORIGINAL
LINE OF CONVECTION AHEAD OF THE SURFACE TROUGH THIS MORNING HAS
DISSIPATED AND GIVEN WAY TO A STRONGER LINE NOW STRETCHING FROM
NORTHWEST OF MINOT TO SOUTHWEST OF BISMARCK...MOVING TO THE EAST
AROUND 25 KTS. THESE THUNDERSTORMS ARE ALIGNED ALONG THE SURFACE
BOUNDARY NEAR THE AXIS OF GREATEST INSTABILITY. AS THE SHORT-WAVE
ALOFT PROPAGATES ACROSS EASTERN ND AND NORTHWEST MN THIS EVENING
AND OVERNIGHT...THESE STORMS WILL CONTINUE TO MOVE ACROSS ND/MN.
HOWEVER...INSTABILITY IS WEAK ALONG AND EAST OF THE VALLEY...SO
THE EXTENT TO WHICH THEY HOLD TOGETHER IS IN QUESTION. THE RAP
WITH SUPPORT FROM THE GFS/NAM DISSIPATE THESE STORMS EAST OF THE
VALLEY AND IF THIS VERIFIES...CURRENT POPS MAY BE TOO HIGH. GIVEN
HIGHER INSTABILITY TO THE WEST...SOME THUNDERSTORMS COULD BE STRONG
AND EVEN SEVERE ACROSS THE DEVILS LAKE BASIN. HOWEVER...NO SEVERE
CONVECTION IS EXPECTED ALONG AND EAST OF THE VALLEY.
MUCH OF TUESDAY SHOULD BE DRY AS THE REGION IS BETWEEN WEATHER
SYSTEMS...BUT SHOWER AND THUNDERSTORM CHANCES INCREASE AGAIN LATE
IN THE DAY AND OVERNIGHT AS A STRONG CANADIAN SHORT-WAVE AND
ASSOCIATED COLD FRONT MOVE ACROSS THE FORECAST AREA. THE HIGHEST
INSTABILITY WILL REMAIN ACROSS SD INTO SOUTHWEST MN...BUT MODELS
INDICATE MLCAPE UP TO 1500 J/KG MAINLY ALONG AND SOUTH OF THE I-94
CORRIDOR BY TUESDAY AFTERNOON. WITH THE APPROACHING COLD FRONT AND
50+ KTS OF 0 TO 6 KM BULK SHEAR ASSOCIATED WITH A 60 TO 80 KT 300
HPA JET STREAK...MODELS HINT AT A CONVECTIVE COMPLEX DEVELOPING
SOMEWHERE NEAR THE ND/SD BORDER. SPC DAY 2 CONVECTIVE OUTLOOK
SHOWS A SLIGHT RISK FOR SEVERE CONVECTION IN THIS AREA AND THIS
SEEMS REASONABLE. EXACT PLACEMENT OF ANY COMPLEX THAT DOES DEVELOP
IS UNCERTAIN AS IS THE EASTWARD EXTENT TO THE SEVERE POTENTIAL...
SO SOMETHING TO FINE-TUNE IN THE NEXT FORECAST PACKAGE IF POSSIBLE.
THERMAL RIDGE AXIS MOVES OVERHEAD IN FRONT OF THE COLD FRONT...SO
HIGHS TUESDAY WILL REACH THE UPPER 70S TO NEAR 80 DEGREES.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 338 PM CDT MON JUL 29 2013
WEDNESDAY AND THURSDAY WILL BE DRY WITH SURFACE HIGH PRESSURE
BUILDING ACROSS THE FORECAST AREA. TEMPERATURES WILL BE A BIT
COOLER WITH HIGHS IN THE 70S AND LOWS IN THE 50S. WINDS WILL BE
BREEZY FROM THE NORTHWEST WEDNESDAY BEFORE BECOMING LIGHT ON
THURSDAY AS THE PRESSURE GRADIENT RELAXES.
HIGH PRESSURE WILL REMAIN FROM MANITOBA INTO EASTERN NORTH DAKOTA
FRIDAY INTO SATURDAY KEEPING US DRY WITH TEMPERATURES REMAINING
NEARLY 10 DEGREES BELOW AVERAGE. HIGH PRESSURE MOVES EAST INTO THE
WESTERN GREAT LAKES REGION BY LATE SUNDAY ALLOWING NEXT SHORT WAVE
AND SURFACE LOW TO MOVE INTO THE NORTHERN PLAINS. THIS SYSTEM WILL
GIVE THE RISK OF SHOWERS AND THUNDERSTORMS SUNDAY TO EASTERN NORTH
DAKOTA AND PARTS OF WESTERN MINNESOTA...WHILE EASTERN FCST AREA WILL
REMAIN DRY. WILL GO WITH MOSTLY 30-40 POPS MONDAY AS SYSTEM MOVES
THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 108 PM CDT MON JUL 29 2013
AFTERNOON DIURNAL CUMULUS FIELD IN NW MN WILL BE AROUND THROUGH
00Z...MOSTLY SCATTERED BUT LOCALLY VFR BROKEN. OTHERWISE
CONSIDERABLE HIGH CLOUDS WILL BE PRESENT INTO TONIGHT AS SURFACE
TROUGH MOVES SLOWLY EAST THRU ERN ND LATE TONIGHT. HRRR 3 KM
INDICATES SHOWERS TO MOVE INTO DVL REGION BY 00Z AND THEN INTO NRN
VALLEY 02-03Z SO TIMED PRECIP INTO DVL-GFK-TVF BASED ON THAT. SOME
GUSTY SOUTH WINDS TO 20-22KTS DVL INTO GFK THIS AFTN...THEN
DIMINISHING TO UNDER 10 KTS TONIGHT. THREAT FOR PRECIP ESP IN SE
ND INTO WCNTRL MN TUESDAY MIDDAY-AFTN BUT NOT INCLUDED IN LATE
PERIODS OF TAFS AT THIS TIME DUE TO TIMING UNCERTAINTIES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/RIDDLE
AVIATION...RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
108 PM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 108 PM CDT MON JUL 29 2013
SHOWERS ACROSS NORTHEAST SD HAVE MOVED FARTHER NORTH AND EAST THAN
PREVIOUSLY FORECAST...SO ADDED CHANCE POPS ACROSS SOUTHEAST ND
THROUGH MUCH OF THE AFTERNOON. STILL THINK THE MAIN SHOW WILL BE
THE SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND WESTERN ND
ASSOCIATED WITH THE SURFACE TROUGH AND SHORT-WAVE ALOFT. PRIMARY
CONVECTIVE LINE IS NOW APPROACHING RUGBY...SO INCREASED CHANCE
POPS FARTHER EAST ACROSS THE NORTHERN VALLEY THIS AFTERNOON. A
SECONDARY CONVECTIVE LINE HAS DEVELOPED ALONG THE PRIMARY SURFACE
WIND SHIFT FROM ESTEVAN MB TO WILLISTON TO BAKER MT AND THIS TOO
WILL MAKE ITS WAY ACROSS THE STATE THIS AFTERNOON AND EVENING.
ADJUSTED HOURLY TEMPERATURE AND SKY GRIDS TO BLEND WITH LATEST
OBSERVATIONS. OTHERWISE...FORECAST IS IN GOOD SHAPE.
UPDATE ISSUED AT 1027 AM CDT MON JUL 29 2013
TRICKY PRECIPITATION FORECAST TODAY AND TONIGHT. WILL FOLLOW THE
LATEST RAP FOR THE MORNING UPDATE WHICH APPEARS TO BEST REFLECT
CURRENT REALITY. TWO AREAS OF SHOWERS/THUNDERSTORMS TO BE CONCERNED
WITH TODAY. THE FIRST IS AN CLUSTER OF SHOWERS NORTH AND WEST OF
ABERDEEN ALONG THE NOSE OF A 30 KT 850 HPA JET AND MID-LEVEL
MOISTURE GRADIENT. THE SECOND IS A LINE OF SHOWERS AND EMBEDDED
THUNDERSTORMS FROM STANLEY TO NORTHWEST OF DICKINSON ASSOCIATED
WITH THE MAIN SURFACE TROUGH AND SHORT-WAVE ALOFT. THE RAP
SUGGESTS THESE TWO AREAS OF PRECIPITATION WILL CONVERGE WEST OF
THE FORECAST AREA THIS AFTERNOON AND THEN MOVE INTO THE VALLEY IN
SOME FORM LATER THIS EVENING. BEST MIXED LAYER INSTABILITY (UP TO
1500 J/KG) WILL BE CONFINED TO THE DEVILS LAKE BASIN...SO SOME
STRONG TO MARGINALLY SEVERE STORMS ARE POSSIBLE IN THIS AREA. FOR
NOW...NOT CERTAIN ON STORM AREAL COVERAGE...SO WILL KEEP POPS IN
THE CHANCE CATEGORY INCREASING FROM WEST TO EAST LATE THIS
AFTERNOON AND EVENING.
LARGE MID-HIGH LEVEL CLOUD SHIELD HAS DEVELOPED AHEAD OF THE
SURFACE TROUGH AND THIS MAY IMPACT TEMPERATURES TODAY. FOR NOW...
INCREASED SKY GRIDS AND SLOWED THE RISE OF HOURLY TEMPERATURES...
BUT KEPT AFTERNOON HIGHS IN THE MID TO UPPER 70S. DEPENDING ON
EVOLUTION OF CLOUDS...MAY HAVE TO KNOCK THESE VALUES DOWN A FEW
DEGREES AT THE 1 PM FORECAST UPDATE.
UPDATE ISSUED AT 640 AM CDT MON JUL 29 2013
CONVECTION IN NORTH CENTRAL ND ALONG THE CANADIAN BORDER LOOKS
LIKE IT WILL AT MOST CLIP NORTHWESTERN TOWNER COUNTY. THUS...WILL
CONTINUE TO KEEP ONLY MINIMAL POPS IN THE NORTHWESTERN CWA UNTIL
LATER THIS AFTERNOON. MINOR TWEAKS TO TEMPS AND WINDS BUT NO MAJOR
CHANGES.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
CONVECTION CHANCES THROUGHOUT THE PERIOD WILL BE THE PRIMARY
FORECAST CONCERN.
THE MAIN UPPER RIDGE AXIS OVER WESTERN MN WILL CONTINUE TO SHIFT
EASTWARD TODAY AS NEAR ZONAL FLOW SETS IN. CONVECTION HAS BEEN
ONGOING SINCE AROUND MIDNIGHT IN NORTHWESTERN ND. THINK THAT THIS
ACTIVITY WILL START TO DISSIPATE AS IT MOVES FURTHER EAST INTO
STABLE AIR. HOWEVER...WILL KEEP AN EYE ON IT AND MAY MAKE SOME
LAST MINUTE ADJUSTMENTS.
SHORTWAVE OVER ID SHOULD MOVE OUT INTO THE NORTHERN PLAINS TODAY.
SOUTHERLY WINDS WILL BE PICKING UP AS THE SFC TROUGH AXIS MOVES
INTO ND...SO THERE SHOULD BE SOME RETURN FLOW. ON THE OTHER
HAND...MODELS ARE IN PRETTY DECENT AGREEMENT THAT THE BEST
INSTABILITY AXIS WILL REMAIN TO OUR WEST THIS AFTERNOON. THINK
THAT SOME PRECIP MAY ENTER THE DEVILS LAKE BASIN THIS
AFTERNOON...BUT THE EASTERN TWO THIRDS OF THE CWA WILL NOT SEE
MUCH UNTIL TONIGHT. AT THIS POINT IT SEEMS THAT STORMS MOVING
THROUGH WILL BE SUB SEVERE.
NEAR ZONAL FLOW CONTINUES INTO TUESDAY...WITH A STRONGER SHORTWAVE
TROUGH MOVING INTO MANITOBA. A SFC TROUGH AXIS WILL SET UP OVER
THE CENTRAL CWA AND COULD BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT. SFC BASED CAPE VALUES WILL BE AROUND 1500 J/KG...AND
DEEP LAYER BULK SHEAR WILL BE AROUND 40 KTS OR SO. THE MAIN COLD
FRONT AND UPPER FORCING DO NOT MOVE IN UNTIL TUESDAY NIGHT THOUGH
SO JUST KEPT POPS IN THE 30 PERCENT RANGE BEFORE 00Z.
AS FOR TEMPERATURES...CONTINUED A SLOW WARMING TREND WITH HIGHS
BACK AROUND 80 DEGREES IN SOME AREAS FOR TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
TUESDAY NIGHT...A COLD FRONT MOVING THROUGH ALONG WITH THE MAIN UPPER
TROUGH DIGGING DOWN OUT OF CANADA SHOULD PROVIDE THE FOCUS FOR
CONTINUED THUNDERSTORM DEVELOPMENT. BUMPED UP POPS A BIT INTO THE
HIGH CHANCE RANGE FOR OVERNIGHT HOURS...WITH A BIT OF PRECIP
LINGERING IN THE SOUTHEAST WEDNESDAY MORNING. WEDNESDAY AND
WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH SFC HIGH PRESSURE
BUILDING IN AND NORTHWESTERLY FLOW ALOFT. TEMPS WILL GET KNOCKED
BACK A BIT INTO THE 70S BEHIND THE COLD FRONT ON WEDNESDAY.
THURSDAY-SUNDAY...
A VERY STAGNANT UPPER FLOW PATTERN IS EXPECTED TO PERSIST THROUGH
THE MAJORITY OF THIS PERIOD. NORTHWEST FLOW ALOFT WILL BE MAINTAINED
ACROSS THE NORTHERN PLAINS IN BETWEEN A BLOCKING UPPER LEVEL RIDGE
ACROSS WESTERN CANADA AND A TROUGH OVER EASTERN CANADA...WITH THE
SUBTROPICAL RIDGE REMAINING ANCHORED ACROSS THE SOUTHERN HIGH
PLAINS. THIS PATTERN WILL KEEP DEEP MOISTURE SOUTH OF THE
REGION...AND PRECIP CHANCES LOW OVERALL...ALTHOUGH A FEW SHOWERS ARE
POSSIBLE WITH ANY WAVES DROPPING OUT OF CANADA.
TEMPS ON THURSDAY MAY APPROACH SEASONAL NORMS IN THE 70S TO NEAR 80.
HOWEVER...OPERATIONAL MODELS SUGGEST A STRONGER WAVE WILL PUSH
THROUGH THURSDAY NIGHT...WITH BROAD SFC HIGH PRESSURE NOSING INTO
THE NORTHERN PLAINS FOR LATE WEEK. A SURGE OF REINFORCING COOLER AIR
AMIDST NORTHERLY LOW-LEVEL FLOW WILL KEEP TEMPS BELOW NORMAL THROUGH
NEXT WEEKEND.
BY LATE NEXT WEEKEND...THE 00Z GFS/ECMWF TEMPORARILY FLATTEN THE
UPPER FLOW AND KICK THE WESTERN US UPPER LOW EASTWARD...WITH THE 00Z
ECMWF A BIT MORE ROBUST WITH MOISTURE RETURN AND PRECIP CHANCES.
CONFIDENCE IN ANY SCENARIO AT THIS RANGE IS LOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 108 PM CDT MON JUL 29 2013
AFTERNOON DIURNAL CUMULUS FIELD IN NW MN WILL BE AROUND THROUGH
00Z...MOSTLY SCATTERED BUT LOCALLY VFR BROKEN. OTHERWISE
CONSIDERABLE HIGH CLOUDS WILL BE PRESENT INTO TONIGHT AS SURFACE
TROUGH MOVES SLOWLY EAST THRU ERN ND LATE TONIGHT. HRRR 3 KM
INDICATES SHOWERS TO MOVE INTO DVL REGION BY 00Z AND THEN INTO NRN
VALLEY 02-03Z SO TIMED PRECIP INTO DVL-GFK-TVF BASED ON THAT. SOME
GUSTY SOUTH WINDS TO 20-22KTS DVL INTO GFK THIS AFTN...THEN
DIMINISHING TO UNDER 10 KTS TONIGHT. THREAT FOR PRECIP ESP IN SE
ND INTO WCNTRL MN TUESDAY MIDDAY-AFTN BUT NOT INCLUDED IN LATE
PERIODS OF TAFS AT THIS TIME DUE TO TIMING UNCERTAINTIES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1106 AM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 1105 AM CDT MON JUL 29 2013
LOCAL RADAR SHOWING AN UPSCALE TREND IN AREAL COVERAGE AND
INTENSITY OF THUNDERSTORMS APPROACHING MINOT. HAVE ADJUSTED POPS
AND WEATHER GRIDS ACCORDINGLY FOR THE NEXT FEW HOURS. LATEST
VISIBLE IMAGERY SHOWS A BRIEF BREAK IN THE CLOUDS WEST IN BETWEEN
SUCCESSIVE SHORTWAVES. ANY CLEARING/HEATING WILL LEAD THE WAY TO
AN INCREASE THREAT FOR STRONG TO SEVERE THUNDERSTORMS BY MID TO
LATE AFTERNOON. WILL CONTINUE TO MONITOR.
UPDATE ISSUED AT 825 AM CDT MON JUL 29 2013
LATEST WATER VAPOR IMAGERY AND LOCAL/REGIONAL RADAR SHOWS A COUPLE
OF SHORTWAVES LINING UP FROM CENTRAL MONTANA INTO CENTRAL NORTH
DAKOTA THIS MORNING. UPPER DIVERGENCE FIELD PER SREF SEEMS TO MESH IN
PRETTY WELL WHERE SHOWERS/THUNDERSTORMS ARE DEVELOPING...ESPECIALLY
OVER THE WEST AND NORTH CENTRAL. THE LATEST HRRR MODEL IS
FORECASTING A LINE OF SHOWERS AND THUNDERSTORMS TO IMPINGE ON OUR
WESTERN BORDER BY 17Z TO 18Z WITH A PROGRESSIVE/EASTWARD MOVEMENT
THIS AFTERNOON INTO SOUTH CENTRAL NORTH DAKOTA. THIS SEEMS
REASONABLE PER UPSTREAM WEATHER IN CENTRAL MONTANA.
FOR THIS MORNINGS UPDATE...BASED ON THE ABOVE...HAVE HAVE BOOSTED
POPS WEST AND NORTH CENTRAL...AND CHANGED WORDING TO AREAL
COVERAGE/SCATTERED...VERSUS UNCERTAINTY. BISMARCK SOUNDING AND
CLOUD COVER OUTSIDE OF THE OFFICE STILL SHOWS A CAP IS IN
PLACE...BUT WITH THE APPROACH OF THE UPSTREAM SHORTWAVES...ENOUGH
COOLING ALOFT WILL ALLOW FOR SCATTERED THUNDERSTORMS THIS
AFTERNOON. THUS HAVE MENTIONED ISOLATED SHOWERS FOR THE MORNING
AND THEN INTRODUCED THUNDER FOR THE AFTERNOON FROM BISMARCK EAST.
UPDATE ISSUED AT 636 AM CDT MON JUL 29 2013
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS...OTHERWISE LITTLE CHANGE TO THE GOING FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON JUL 29 2013
THE SHORT RANGE MODELS...INCLUDING THE HIGH RESOLUTION CONVECTIVE
SHORT TERM MODELS...WERE DOING A POOR JOB WITH CONVECTION
OCCURRING AT THE TIME OF THIS WRITING. THIS HAS BEEN THE CASE FOR
THE PAST 24 HOURS AS WELL. THE MODEL GUIDANCE IS REASONABLE...
BASED ON POSITION OF SURFACE LOW TROUGH THROUGH EASTERN MONTANA
AND PLACEMENT AND MOVEMENT OF MID LEVEL DISTURBANCES...IT IS JUST
THAT THE ATMOSPHERE IS NOT COOPERATING AND REACTING AS EXPECTED.
HAVE NOW CASTED THE ONGOING CONVECTION FOR THE NEXT 8 HOURS AND
THEN...IN COLLABORATION WITH NEIGHBORING OFFICES...BLANKETED THE
WEST WITH CHANCE POPS...AND SPREAD THEM EAST THROUGH THE DAY.
AS THE SURFACE TROUGH MOVES INTO THE WESTERN DAKOTAS TODAY...AND
MOISTURE POOLS AROUND IT ON SOUTHEAST SURFACE WINDS AND
INCREASINGLY MOIST (HIGHER DEW POINT) AIR...ENOUGH INSTABILITY
SHOULD BE RELEASED TO TRIGGER DEEP MOIST CONVECTION ACROSS EASTERN
MONTANA AND THE WESTERN DAKOTAS. THIS WILL BE AIDED BY THE NEXT
WEAK MID LEVEL WAVE APPROACHING.
SEVERE WEATHER PARAMETERS ARE LACKING...SO AS FAR AS SEVERE
CONVECTION GOES...NOTHING BUT ISOLATED SEVERE IS ANTICIPATED.
TONIGHT...AS THE SYSTEM MOVES EAST...STORMS WILL END FROM THE
WEST...IN THE EVENING FROM WILLISTON TO DICKINSON...AND BY
MIDNIGHT FROM MINOT TO BISMARCK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON JUL 29 2013
MEDIUM TO LONG RANGE FORECAST MODELS ARE IN DECENT AGREEMENT FOR
MUCH OF THE LONG TERM FORECAST PERIOD.
MODELS CONTINUE TO INDICATE AN ACTIVE TUESDAY/TUESDAY
NIGHT...ESPECIALLY ALONG TO SOUTH OF INTERSTATE 94 WHERE A LINGERING
SFC BOUNDARY/COLD FRONT WILL COINCIDE WITH DIVERGENT FLOW ALOFT IN
THE RRQ OF AN UPPER LEVEL JET STREAK AND MUCAPE NEARING 1-1.5K J/KG
MID TO LATE AFTERNOON. FARTHER NORTH...A POTENT MID LEVEL TROUGH
WILL SWING EAST ACROSS SOUTH CENTRAL CANADA...INTO LAKE WINNIPEG
LATE AFTERNOON. THIS WILL DRIVE THE SFC COLD FRONT SOUTH INTO SOUTH
DAKOTA BY MID EVENING. BEST CHANCE OF SEVERE WEATHER STILL LOOKS
FROM THE INTERSTATE 94 CORRIDOR COUNTIES SOUTH INTO SOUTH DAKOTA
WITH INSTABILITY TAPERING OFF TO THE NORTH OF THE FRONT. MAIN
QUESTION IS WILL THE MORNING CONVECTION ADVERTISED BY MODELS OVER
EASTERN MONTANA/WESTERN NORTH DAKOTA AND RESULTANT CLOUD COVER BE
ENOUGH TO SHUN THE SEVERE POTENTIAL? OR ARE MODELS PERHAPS
SUGGESTING STRONG TO SEVERE CONVECTION ONGOING TUESDAY MORNING BEING
MAINTAINED THROUGH THE AFTERNOON ALONG THE FRONTAL BOUNDARY?
REGARDLESS...POP WILL BE HIGH GIVEN THE DYNAMICS IN PLACE WITH THE
MAIN QUESTION BEING HOW STRONG WILL THE STORMS BE. WILL MAINTAIN A
HIGH POP FOR MOST LOCATIONS TUESDAY MORNING...AFTERNOON...AND
EVENING...TRENDING DOWN LATE TUESDAY NIGHT/EARLY WED MORNING.
AFTER TUESDAY NIGHT...NORTHWEST FLOW ALOFT DEVELOPS ALONG WITH
SURFACE HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA INTO EASTERN
SOUTH DAKOTA. STABLE AIR ACCOMPANIES THE SFC HIGH SO HAVE REMOVED
ALL MENTION OF PRECIPITATION WED/WED NIGHT...AND TRENDED DOWN
THURSDAY/THURS NIGHT LEAVING A THUNDERSTORM MENTION FAR SOUTH AND
FAR WEST FOR NOW. FOR FRIDAY...PATTERN REMAINS IN PLACE ALTHOUGH WE
DO START TO SEE RETURN FLOW WEST WHERE I HAVE KEPT THUNDERSTORMS IN
THE FORECAST.
LATEST 00Z MODELS DEVELOP A QUASI-ZONAL FLOW OVER THE NORTHERN
PLAINS FOR NEXT WEEKEND WHICH WOULD RESULT IN BETTER CHANCES FOR
MORE WIDESPREAD SHOWERS/THUNDERSTORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1105 AM CDT MON JUL 29 2013
MAINLY VFR CIGS/VSBYS OUTSIDE OF ANY THUNDERSTORMS. SCATTERED
SHOWERS AND THUNDERSTORMS WILL BE COMMON THROUGH THE AFTERNOON AND
EARLY EVENING. HAVE INSERTED PREDOMINANT THUNDERSTORM CONDITIONS
WHERE CONFIDENCE WAS HIGHER...AT KMOT/KISN/KDIK/KBIS. WILL
CONTINUE WITH THE VCTS AT KJMS UNTIL THE COVERAGE GETS CLOSER AND
CONFIDENCE IS HIGHER TO MENTION PREDOMINANT. EXPECT MVFR TO POSSIBLE
IFR CIGS/VSBYS IN THE STRONGER THUNDERSTORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JPM
LONG TERM...NH
AVIATION...KS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
235 PM CDT MON JUL 29 2013
.SHORT TERM...(TONIGHT AND TUESDAY)
ISSUED AT 235 PM CDT MON JUL 29 2013
A BIT OF UPPER LEVEL ENERGY WILL WORK WITH THE 850 MB LOW LEVEL
JET/MOISTURE TRANSPORT TO FIRE A SHOWER/THUNDERSTORM COMPLEX IN THE
IA/MO VICINITY TONIGHT...TRACKING IT EAST ON TUES. WHILE THIS
COMPLEX IS EXPECTED TO STAY SOUTH OF THE FORECAST AREA...THERE IS
SOME MEAGER MOISTURE TRANSPORT INTO THE REGION...ALONG WITH A 700 MB
LOW AND WEAK LOW LEVEL TEMPERATURE ADVECTION. MESO MODELS AND 29.12
RUNS OF GFS AND NAM SUGGEST THAT THERE WILL BE ENOUGH CONVERGENCE TO
PRODUCE SCATTERED/ISOLATED SHOWERS LATE TONIGHT THROUGH AT LEAST THE
TUE MORNING. RADAR TRENDS TO THE WEST MIRROR THIS. WILL CONTINUE
SHOWER CHANCES FOR NOW...LITTLE/IF ANY INSTABILTY FOR STORMS.
CHANCES MAY NEED TO BE INCREASED IF THE AREAL COVERAGE LOOKS MORE
WIDESPREAD. AMOUNTS SHOULD BE FAIRLY SMALL FOR THOSE LOCATIONS THAT
RECEIVE SOME RAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 235 PM CDT MON JUL 29 2013
500 MB SHORTWAVE TROUGH STILL ON TRACK TO SLIDE WEST-EAST ACROSS
SOUTHERN CANADA OVER THE NEXT COUPLE DAYS...SKIMMING NORTHERN
PORTIONS OF THE GREAT LAKES ON WED. WHILE THE BULK OF THE UPPER
LEVEL FORCING WILL BE TO THE NORTH...THE SYSTEM WILL DRAG A SFC
FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MORE CONSENSUS IN
TIMING OF THE FRONT...WITH THE PREVIOUSLY FAST GFS COMING MORE
INLINE WITH THE NAM AND ECMWF. CONVERGENCE IS SOMEWHAT MEAGER AROUND
THE FRONT...BUT THERE WILL BE ABOUT 1000-1500 J/KG SBCAPE FOR IT TO
TAP...ALTHOUGH BUFKIT SOUNDINGS SHOW ITS FAIRLY SKINNY AND NOT
CONDUCIVE TO STRONG UPDRAFTS. THERE IS GOOD SHEAR OF 35-40 KTS IN
THE 0-6 KM LAYER. IF THE SYSTEM LOOKED MORE DYNAMIC...TIMING WOULD
FAVOR SEVERE WEATHER. AS IT STANDS NOW...SEE STRONG/ISOLATED SEVERE
STORMS MORE LIKELY - AS LONG AS THE INSTABILTY IS THERE. THERE IS
LOW LEVEL WARM AIR ADVECTION/ISENTROPIC UPGLIDE PRE-FRONT...WHICH
COULD RESULT IN SOME CLOUDS/SCATTERED SHOWERS IN THE MORNING. THIS
COULD MUCK UP THE ATMOSPHERE...LEAVING LESS INSTABILTY TO WORK ON.
NOT CLEAR HOW THIS WILL PLAY OUT...BUT THERE WILL BE A GOOD SHOT FOR
SHOWERS/STORMS ON WED...LIKELY MORE WIDESPREAD ACROSS THE NORTH.
ON THU...AREA IS UNDER CYCLONIC FLOW AND THE GFS AND NAM SUGGEST
THAT A PIECE OR TWO OF UPPER LEVEL ENERGY COULD TRACK ACROSS
NORTHERN PARTS OF THE REGION. ADD IN MLCAPES 500-1000 J/KG AND THIS
COULD BE ENOUGH TO SPARK A FEW SHOWERS ACROSS THE NORTH/NORTHEAST.
CONFIDENCE NOT HIGH ENOUGH TO ADD TO THE FORECAST AT THE
MOMENT...BUT IF SIGNAL PERSISTS...SMALL CHANCES WILL BE NEEDED. PCPN
AMOUNTS WOULD BE MINIMAL.
FOR FRIDAY...THE GFS CONTINUES TO FAVOR KEEPING RAIN CHANCES
ASSOCIATED WITH A WEAK SHORTWAVE/LEFT-OVER CONVECTIVE COMPLEX SOUTH
OF THE AREA. A TREND IT STARTED YESTERDAY. THE ECMWF IS ALSO FARTHER
SOUTH...WHICH IT HINTED AT IN ITS PREVIOUS RUN. THE GEM WOULD BRING
US PRETTY GOOD RAINS...DUE TO DEVELOPING THE THU NIGHT STORM COMPLEX
A WHOLE STATE NORTH OF THE OTHER MODELS. GOING TO STICK WITH THE
SOUTHERN SOLUTIONS FOR NOW...WHICH HAS BEEN CONSENSUS.
MODELS HOLD THE PROMISE OF A DRY WEEKEND FOR THE REGION...WITH WEAK
SFC HIGH PRESSURE MOVING OVERHEAD AND ANY RIPPLES IN THE NORTHWEST
FLOW SHUTTLING NORTH OR SOUTH OF THE FORECAST AREA. OF COURSE...IN A
RELATIVELY DIRTY FLOW SUCH AS WHAT IS EXPECTED...THIS CAN CHANGE.
TEMPERATURES WILL BE MUCH MORE PLEASANT COMPARED TO LAST
WEEKEND...BUT THE PATTERN WILL STILL KEEP THEM NEAR OR BELOW THE
LATE JULY/EARLY AUGUST NORMALS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUL 29 2013
THE 29.12Z MODELS ARE IN GOOD AGREEMENT THAT A MID LEVEL SHORT
WAVE TROUGH WILL MOVE THROUGH THE REGION ON TUESDAY MORNING. A
BROKEN DECK INSTABILITY OF CUMULUS WILL BE SEEN ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON...AND THEN CONTINUE
INTO TONIGHT AS LOW LEVEL MOISTURE CONTINUES TO SURGE INTO THE
REGION. ARW AND RAP CONTINUE TO SUGGEST THAT SCATTERED SHOWERS
WILL MOVE INTO THE KRST AROUND 30.05Z...AND THEN CONTINUE THROUGH
THE REMAINDER OF THE MORNING. EXPECT THE CEILINGS TO BECOME MVFR
AFTER 30.09Z IN KRST. WITH SHOWERS SATURATING THE BOUNDARY LAYER
EXPECT THAT BR WILL REDUCE VISIBILITIES INTO THE MVFR RANGE FROM
30.09Z TO 30.15Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1247 PM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT MON JUL 29 2013
QUIET WEATHER IN PLACE DURING THIS PERIOD. DEEP LOW PRESSURE AREA
CONTINUES TO PRESS EAST AND SKIES HAVE CLEARED. WAITING ON VALLEY
FOG TO FORM...WHICH SHOULD DISSIPATE QUICKLY THIS MORNING. HIGH
PRESSURE BUILDING IN AND SOUTHERLY RETURN FLOW HAS BEGUN IN THE
HIGH PLAINS WITH ABUNDANT CLOUD AND RAIN SHOWERS PER RADARS ACROSS
NEB/KS. 06Z PROFILER IN CENTRAL KS INDICATES ONE HOUR AVERAGE OF
40 KTS MOVING MOISTURE NORTH AND CONVERGING IT. THIS IN RESPONSE
TO MUDDLED SHORTWAVE TROUGH ENERGY OVER THE ROCKIES IN WRLY FLOW.
MOISTURE SOURCE IS STILL IN OK JUST SOUTH OF THE FRONT LYING FROM
SWRN CO TO ARKANSAS.
TONIGHT THE FRONTAL BOUNDARY IN THE SRN PLAINS WILL BEGIN TO LIFT
NORTH AND BECOME CONVECTIVELY ACTIVE AS SOUTHERLY FLOW BEGINS
ACROSS MOST OF THE PLAINS. A CONVECTIVE COMPLEX WILL RESULT OVER
I-80 CORRIDOR AND SOUTH...WITH BROAD MOISTURE ADVECTION ARRIVING
IN THE SWRN FORECAST AREA BY TUESDAY SUNRISE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUL 29 2013
FORECAST CHALLENGES WERE THE WEAK LIFT ENVIRONMENT TUESDAY INTO
AND INCLUDING THE FRONTAL PASSAGE WEDNESDAY. SEVERE WEATHER
CHANCES WEDNESDAY WERE ALSO REFINED...VERY GOOD WIND SHEAR...POOR
FRONTAL CONVERGENCE AND LESSER CAPE.
300/305K ISENTROPIC SURFACES INDICATE VERY WEAK LIFT FROM KC-GRB
WITH MIXING RATIO VALUES INCREASING FROM 3 TO 9 G/KG RAPIDLY
TUESDAY MORNING. SOME WEAK CONVERGENCE WITH THIS ADVECTION OF HIGH
MOISTURE FROM W-E TUESDAY. WEATHER OUTCOME IS A 600-800MB LAYER
OF HIGH RH AND THICKER CLOUDS FOR TUESDAY. 29.00Z/03Z MODEL GUIDANCE
/SREF/NAM/GFS/ AGREE VERY WELL ON THIS FORECAST...INCREASING THE
CONFIDENCE. THIS CLOUD INCREASE WAS A MAJOR CHANGE TO THE
FORECAST. ALTHOUGH ONLY WEAK LIFT IS FORECAST...SOUTHERN TAIL OF
NORTHERN-PASSING SHORTWAVE TROUGH WILL ALSO PROVIDE A BIT OF
LIFT TUESDAY TO ALLOW SOME SHOWERS TO POSSIBLY POP UP. THUS...HAVE
AGAIN RE-ADDED THE RAIN CHANCES IN THE MOIST ENVIRONMENT
TUESDAY...THESE MAY NEED TO BE INCREASED MORE. WOULD THINK SOME
SCT/ISO SHRA WILL BE AROUND.
WHILE THE WEAK FORCING TUESDAY WEAKENS AND SHIFTS EAST TUESDAY
NIGHT...THE MOISTURE REMAINS TO ALLOW AGAIN AN ISO SHRA CHANCE.
ALL OF THESE ARE GROUND WETTING TYPE SYSTEMS AT MOST. A DRY PERIOD
UNTIL FRONTAL PASSAGE WEDNESDAY LOOKS ON TARGET. HOWEVER...WITH
TIMING ISSUES ON THE FRONT WEDNESDAY...DECIDED TO REMOVE DETAIL
ON THE RAIN CHANCES THAT DAY. HAVE ALSO INCREASED THE RAIN CHANCES
NORTH OF I-94 WITH IMPROVING CONSENSUS ON FORCING AND MOISTURE.THE
29.00Z GFS REMAINS THE FAST SOLUTION WITH THE FRONT...WHILE THE
NAM/ECMWF ARE SLOWER AND HAVE WARM ADVECTION ACROSS THE AREA
WEDNESDAY AT 12Z IN A PRE-FRONTAL ENVIRONMENT. BY 18Z WED...THE
GFS PUSHES THE FRONT THROUGH THE FORECAST AREA INTO CENTRAL
WI...AND HAVE SIDED MORE WITH THE SLOWER SOLUTIONS. 29.03Z SREF
MEAN WOULD BE A BIT OF A COMPROMISE OF THE TWO.
TARGETING THE 925 MB MOISTURE CONVERGENCE...THE BEST SIGNALS ARE
FURTHER NORTHWEST OF THE FORECAST AREA WHICH ISNT PREFERRED FOR
SEVERE WEATHER HERE. WOULD THINK AN AFTERNOON FRONTAL PASSAGE WILL
OCCUR WEDNESDAY WITH MLCAPE AROUND 1000 J/KG...INCREASING SWWRD
INTO IA. THE AREA WILL HAVE GOOD WIND SHEAR IN THE 0-6KM LAYER
WITH ORGANIZED STORMS POSSIBLE. RIGHT NOW THE QUESTION APPEARS TO
BE CONVERGENCE ON THE FRONT AND SUSTAINED FORCING FOR UPDRAFTS.
WOULD THINK IF THIS INCREASES IN FUTURE FORECASTS...A FEW
SUPERCELLS WOULD BE POSSIBLE. HOWEVER...THE SURFACE PRESSURE
GRADIENT AND WIND FLOW IS PRETTY WEAK IN MOST GUIDANCE...SO THINK
THE SEVERE WEATHER WILL BE ANYTHING ABOVE AN ISOLATE STORM OR TWO.
AREAS NORTH OF I-90...CLOSER TO THE STRONGER SHORTWAVE TROUGH
FORCING WOULD PROBABLY BE FAVORED...EVEN IN THE LESSER MLCAPE.
THURSDAY-SUNDAY...THIS PERIOD IS DOMINATED BY NORTHWEST FLOW AND
BELOW NORMAL TEMPERATURES. RAIN CHANCES CONTINUE THURSDAY NIGHT
TO FRIDAY NIGHT FOR A SYSTEM SHIFTING THROUGH THE NORTHWEST FLOW.
MOST OF THE RAIN CHANCES ARE TO THE SOUTH WITH MORE CONVECTIVE
INSTABILITY. THE CHALLENGE FOR WEATHER THIS PERIOD IS DEVELOPING
ENOUGH INSTABILITY IN THE NORTHWEST FLOW FOR GOOD CONVECTIVE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUL 29 2013
THE 29.12Z MODELS ARE IN GOOD AGREEMENT THAT A MID LEVEL SHORT
WAVE TROUGH WILL MOVE THROUGH THE REGION ON TUESDAY MORNING. A
BROKEN DECK INSTABILITY OF CUMULUS WILL BE SEEN ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON...AND THEN CONTINUE
INTO TONIGHT AS LOW LEVEL MOISTURE CONTINUES TO SURGE INTO THE
REGION. ARW AND RAP CONTINUE TO SUGGEST THAT SCATTERED SHOWERS
WILL MOVE INTO THE KRST AROUND 30.05Z...AND THEN CONTINUE THROUGH
THE REMAINDER OF THE MORNING. EXPECT THE CEILINGS TO BECOM MVFR
AFTER 30.09Z IN KRST. WITH SHOWERS SATURATING THE BOUNDARY LAYER
EXPECT THAT BR WILL REDUCE VISIBILITIES INTO THE MVFR RANGE FROM
30.09Z TO 30.15Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1127 AM MDT MON JUL 29 2013
.UPDATE...
ISSUED AT 935 AM MDT MON JUL 29 2013
MINOR CHANGES TO TODAYS FORECAST. LOWERED POPS THE REST OF THIS
MORNING AND DECREASED SKY COVER. STILL EXPECTING ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON AS
THE LOW LEVELS DESTABILIZE. CLOUD COVER HAS SLOWED THE RISE OF
TEMPERATURES THIS MORNING BUT THE HIGH TEMPERATURE FORECAST LOOKS
IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1127 AM MDT MON JUL 29 2013
MVFR CONDITIONS WILL CONTINUE INTO THIS AFTERNOON OVER MUCH OF THE
NEBRASKA PANHANDLE WITH SLOW IMPROVEMENT. WIDELY SCATTERED SHOWERS
AND TSTMS DEVELOPING ALONG THE LARAMIE RANGE BY MID-AFTN SHOULD THEN
SPREAD EASTWARD OVER THE PLAINS THROUGH THE EVENING BEFORE ENDING.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...RE
FIRE WEATHER...HAHN