Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/15/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
353 PM MDT FRI SEP 13 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 335 PM MDT FRI SEP 13 2013
TONIGHT...NEXT DISTURBANCE IS MOVING NORTHEAST ACROSS THE CWA.
LINE OF CONVECTION HAS DEVELOPED OVER BENT AND EASTERN LAS ANIMAS
COUNTY AND IT IS MOVING TO THE NORTHEAST AT 25 TO 35 KNOTS. THE 12Z
AND 18Z NAM SUGGESTED THE HEAVIEST PRECIPITATION WOULD MOVE ACROSS
THE EASTERN PLAINS. SO FAR...THE CELLS HEADING TOWARDS EL PASO AND
TELLER COUNTIES ARE WEAK. HRRR HAS NOT BEEN DOING WELL TODAY...AS
18Z HRRR HAS MUCH MORE CONVECTION OVER EL PASO COUNTY AT THIS TIME.
BELIEVE THE NAM AND GFS HAS A BETTER HANDLE ON CONVECTION. WILL NOT
ISSUE A FLASH FLOOD WATCH FOR EL PASO AND TELLER COUNTIES THIS
EVENING...AS CHANCES FOR SLOWER MOVING CELLS WITH HEAVY RAINFALL IS
LOW. CANNOT TOTALLY RULE OUT A STRONG CELL OVER A BURN SCAR...BUT
CHANCES OF THIS HAPPENING ARE SMALL. CONVECTION OF THE CWA WILL
MOSTLY END BY MID EVENING. KEPT POPS OVERNIGHT AS SOME SHOWERS ARE
POSSIBLE WITH ABUNDANT MOISTURE AND CYCLONIC FLOW.
SATURDAY...TROUGH APPROACHES THE REGION FROM THE SOUTHWEST...AND
FLOW ALOFT TURNS MORE TO THE SOUTHWEST. STILL PLENTY OF MOISTURE
WITH BUFKIT SOUNDINGS SHOWING PRECIPITABLE WATERS OF 8 TENTHS OF AN
INCH AND GREATER. MAIN CHALLENGE FOR CONVECTION IS THE AMOUNT OF
INSTABILITY. NAM AND GFS SUGGEST THE GREATEST INSTABILITY WILL BE
OVER AND NEAR THE MOUNTAINS...AND HAVE HIGH SCATTERED TO SOME LIKELY
POPS DURING THE AFTERNOON. GIVEN THE ABUNDANT MOISTURE...SOME
STRONGER STORMS COULD PRODUCE LOCALLY HEAVY RAIN...WHICH COULD CAUSE
PROBLEMS ON THE BURN SCARS. GIVEN THE LACK OF DEEP UPSLOPE AND LACK
OF INSTABILITY...BELIEVE CHANCES FOR FLASH FLOODING OVER BURNS SCARS
AND OTHER SUSCEPTIBLE AREAS IS LOW ENOUGH TO NOT WARRANT A FLASH
FLOOD WATCH. --PGW--
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 PM MDT FRI SEP 13 2013
...NEXT HEAVY RAIN THREAT ARRIVES BY SUNDAY MORNING...
OLD UPPER TROUGH OPENS UP AND BEGINS TO MOVE EAST ACROSS COLORADO
SATURDAY. THERE IS STILL ADEQUATE MOISTURE FOR STORMS TO DEVELOP
IN THE AFTERNOON...BUT WITH THE TROUGH OPENING UP...THERE DOESN`T
SEEM TO BE ANYTHING TO REALLY FOCUS THE ENERGY AND GET ANYTHING
WIDESPREAD GOING. SO...GENERALLY ISOLATED TO SCATTERED COVERAGE OF
STORMS SATURDAY...MAINLY OVER THE MOUNTAINS. HEAVY RAIN POTENTIAL
WILL STILL EXIST...BUT AGAIN...MORE HIT AND MISS THAN IN RECENT
DAYS.
ON SUNDAY...WE WILL HAVE SOMETHING TO FOCUS THE PRECIPITATION
AGAIN. SUNDAY MORNING...AND POSSIBLY EVEN LATE SATURDAY NIGHT...
WE WILL HAVE A RATHER SIGNIFICANT COOL FRONT MOVE THROUGH THE
EASTERN PLAINS...ASSOCIATED WITH A SHORTWAVE MOVING THROUGH
THE CENTRAL UNITED STATES. THE COOL FRONT WILL FORCE UPSLOPE
FLOW AGAINST THE MOUNTAINS...TRIGGERING FAIRLY WIDESPREAD
PRECIPITATION...WITH EMBEDDED CONVECTION...FOR LOCALLY HEAVIER
PRECIP. SO...THIS DAY WILL BE A HIGH THREAT DAY AGAIN FOR
AREA BURN SCARS. AND...WITH THE RECENT SATURATION THAT HAS
OCCURRED...OTHER AREAS COULD SEE SOME PROBLEMS AS WELL. THIS
WILL LAST INTO SUNDAY NIGHT...MAINLY AFFECTING THE EASTERN
MOUNTAINS AND PLAINS.
MONDAY...WE START TO FINALLY TRANSITION OUT OF THIS PATTERN
INTO A MUCH DRIER ONE. COULD STILL BE SOME SPOTTY STUFF
AROUND TO CONTEND WITH MONDAY...BUT THE REST OF THE WEEK
DEFINITELY LOOKS MUCH DRIER AND WARMER AS A MUCH DRIER
WESTERLY FLOW ALOFT TAKES HOLD OVER COLORADO. LW
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 335 PM MDT FRI SEP 13 2013
ANTICIPATE SOUTHERLY COMPONENT FLOW AT KCOS THROUGHOUT THE
NIGHT...WHICH WOULD TEND TO KEEP MVFR CONDITIONS OVERNIGHT. FLOW AT
KPUB WILL HAVE ENOUGH OF A WESTERLY COMPONENT TO KEEP VFR CONDITIONS
OVERNIGHT. ON SATURDAY...ABUNDANT MOISTURE WILL REMAIN OVER THE
REGION. INSTABILITY WILL BE LIMITED...AND ONLY ANTICIPATE SCATTERED
AFTERNOON CONVECTION. --PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PGW
LONG TERM...LW
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1124 AM MDT FRI SEP 13 2013
.UPDATE...
ISSUED AT 1012 AM MDT FRI SEP 13 2013
CANCELLED THE FLASH FLOOD WATCH EARLY AS THE RAIN HAS MOVED NORTH
OF EL PASO COUNTY AND ONLY SCATTERED LIGHT RAIN SHOWERS ARE
UPSTREAM OF THE REGION.
SATELLITE SHOWS ANOTHER DISTURBANCE OVER WESTERN NEW MEXICO MOVING
NORTHEAST...AND THIS DISTURBANCE WILL PASS OVER THE REGION BETWEEN
AROUND 4PM AND 8PM TODAY. HAVE SOME CONCERNS THAT THIS NEXT ROUND
OF STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL. HRRR HAS BEEN TRENDING
SLIGHTLY STRONGER WITH THESE STORMS. HOWEVER...WINDS ALOFT HAVE
BECOME SOUTHWEST AT 15 TO 30 KNOTS. STORMS WHICH DEVELOP WILL WANT
TO MOVE TO THE NORTHEAST. AM NOT TOO CONCERNED ABOUT STORMS
TRAINING OVER ONE LOCATION. HOWEVER...STILL HAVE SOME CONCERNS
THAT STORMS COULD PRODUCE SPOTTY AREAS OF LOCALLY HEAVY RAIN. IF
ONE OF THESE SPOTTY STORMS STRIKES A BURN SCAR OR OTHER
SUSCEPTIBLE AREAS...FLASH FLOOD COULD OCCUR. HRRR KEEPS BAND OF
HEAVIER PRECIPITATION JUST NORTH OF THE PALMER DIVIDE WHERE IT WANTS
TO DEVELOP CONVECTION ALONG A BOUNDARY...LIKELY THE DENVER
CYCLONE.
WHAT TO DO ABOUT WATCHES. CURRENTLY...BELIEVE THREAT FOR HEAVY
RAIN NOT SUFFICIENTLY HIGH TO WARRANT EXTENDING THE FLASH FLOOD
WATCH. HOWEVER...THE SITUATION WILL BE MONITORED.
UPDATE ISSUED AT 512 AM MDT FRI SEP 13 2013
A STRONG SOUTHEAST WIND HAS DEVELOPED ALONG THE I-25 CORRIDOR IN
EL PASO AND PUEBLO COUNTIES...AND PRECIPITATION HAS INCREASED OVER
EL PASO COUNTY WITH UP TO AN INCH PER HOUR FALLING IN A VERY
NARROW BAND ACROSS COLORADO SPRINGS. LATEST FORECAST MODELS ARE
SHOWING THE POTENTIAL FOR SOME MODERATE TO HEAVY RAIN THROUGH THE
MORNING HOURS...SO HAVE ISSUED A FLASH FLOOD WATCH THRU 18Z FOR EL
PASO AND TELLER COUNTIES WHERE SOILS ARE ALREADY SATURATED AND
THERE WILL BE A THREAT TO THE WALDO CANYON AND BLACK FOREST BURN SCARS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM MDT FRI SEP 13 2013
RAIN COVERAGE OVR THE SERN PLAINS HAS DECREASED AND HAS BECOME
LIGHTER...WHILE PCPN OVR WESTERN PORTIONS HAS INCREASED TONIGHT WITH
GENERALLY LIGHT TO SOMETIMES MODERATE RAIN BEING REPORTED OVER THE
WEST FORK COMPLEX BURN SCAR. PCPN CONTINUES TO WORK ITS WAY
NORTHWARD FROM NM SO WL KEEP POPS IN THE LIKELY CATEGORY ACRS MOST
OF THE FORECAST AREA FOR THE MORNING HOURS. ALL INDICATIONS ARE
THAT PCPN THAT FALLS OVER EL PASO AND TELLER COUNTIES...WHERE THE
MOST SATURATED CONDITIONS ARE...WL MOSTLY BE ON THE LIGHT SIDE SO
CANCELED THE FF WATCH FOR THE I-25 CORRIDOR AT 3 AM.
THE UPR LOW WL CENTERED NR THE NV...UT AND ID BORDER REGION THRU
MUCH OF THE DAY. IT THEN BEGINS TO SHIFT EASTWARD OVERNIGHT AS IT
PHASES WITH AN UPR TROF WELL TO THE NORTH. THERE WL STILL BE A
PLUME OF MSTR OVR THE FORECAST AREA...ALONG WITH GOOD CHANCES FOR
PCPN...BUT ALL MODELS ARE SHOWING EXPECTED PCPN AMOUNTS BEING ON THE
LIGHTER SIDE TODAY. THAT DOES NOT MEAN THAT THERE WILL NOT BE SOME
LOCALLY HEAVY RAIN STILL WHICH COULD AGAIN CAUSE SOME FLASH
FLOODING.
TONIGHT PCPN CHANCES LOOK LIKE THEY WILL DECREASE...ESPECIALLY OVR
ERN CO. LATE TONIGHT A SHORTWAVE TROF IS EXPECTED TO APPROACH AND
THEN MOVE INTO SWRN CO AND COULD ENHANCE PCPN CHANCES OVR SRN
AREAS...SO WL GO WITH SOME HIGH SCT POPS IN THAT AREA. THE LOCAL
WRF MODEL SHOWS THE POTENTIAL FOR SOME HEAVY RAIN OVERNIGHT ON THE
WEST FORK COMPLEX BURN SCAR...WHILE THE NAM HAS LIGHTER AMOUNTS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 349 AM MDT FRI SEP 13 2013
PRIMARY LONGER TERM ISSUES INCLUDE POPS AND TEMPERATURES. LONGER
TERM COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS SUGGEST
THAT UNSETTLED AND GENERALLY COOL CONDITIONS SHOULD PREVAIL OVER
THE FORECAST DISTRICT INTO THIS WEEKEND BEFORE WARMER AND DRIER
CONDITIONS RETURN NEXT WEEK...ESPECIALLY FROM TUESDAY ONWARD.
AT THIS TIME...IT APPEARS THAT THE CWFA AREAL COVERAGE OF
PRECIPITATION ON SATURDAY WILL BE LESS THAN HAS BEEN NOTED PREVIOUS
FEW DAYS...ALTHOUGH LOCALLY HEAVY RAIN WILL STILL BE POSSIBLE AS
PRECIPITABLE WATER VALUES NEAR 1 INCH AT TIMES AND AREAS SUCH AS
THE RECENT BURN SCARS AND LOCATIONS THAT HAVE RECEIVED HEAVY
RAINFALL DURING THE PREVIOUS FEW DAYS WILL NEED TO BE MONITORED
FOR FLOODING/FLASH FLOODING CONCERNS.
THEN AN INCREASE IN COVERAGE OF PRECIPITATION IS ANTICIPATED ON
SUNDAY AS A NORTHERLY SURGE MOVES ACROSS EASTERN SECTIONS BY
SUNDAY MORNING INCREASING FORECAST PRECIPITABLE WATER VALUES TO
AROUND 1.10 INCHES OVER PORTIONS OF THE I-25 CORRIDOR. ONCE
AGAIN...LOCALIZED FLOODING/FLASH FLOODING ISSUES MAY
ARISE...ESPECIALLY OVER RECENT BURN SCAR AND PREVIOUS HEAVY RAIN
LOCATIONS. IN ADDITION...HIGHER MOUNTAIN LOCATIONS...GENERALLY
ABOVE 12000 FEET MAY EXPERIENCE SEVERAL INCHES OF SNOW FROM
EARLY SATURDAY MORNING INTO MONDAY MORNING.
DRIER AND WARMER CONDITIONS ARE THEN EXPECTED TO DEVELOP OVER THE
FORECAST DISTRICT...ESPECIALLY FROM TUESDAY INTO THURSDAY AS
FORECAST I-25 PRECIPITATION WATER VALUES DECREASE FROM 1.4 INCHES
AS OF THURSDAY NIGHT TO AROUND 0.50 INCHES BY NEXT WEDNESDAY. IN
ADDITION...FORECAST I-25 700 MB TEMPERATURES INCREASE FROM AN 8.8C
VALUE AT 00Z FRIDAY TO A 14.7C VALUE BY 00Z THURSDAY.
FINALLY...GENERALLY LOW-GRADE GRADIENT WINDS SHOULD CONTINUE
OVER THE FORECAST DISTRICT THROUGH NEXT THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1118 AM MDT FRI SEP 13 2013
SHORTWAVE OVER NM WILL CONTINUE TO MOVE NORTH-NORTHEAST AND WILL
BRING ANOTHER ROUND OF SHOWERS TO THE REGION. RAIN IS ALREADY
FALLING IN KALS...AND EXPECT SHOWERS TO MOVE INTO KPUB AND KCOS BY
EARLY TO MID AFTERNOON.
WITH SUSTAINED SOUTHERLY MOIST FLOW...KCOS WILL LIKELY REMAIN MVFR
THROUGHOUT THE DAY. LOCALLY HEAVIER SHOWERS MAY BRING KCOS DOWN TO
IFR FOR BRIEF PERIODS OF TIME.
SOME FOG MAY AFFECT KCOS AND KALS LATER TONIGHT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PGW
AVIATION...HODANISH
AREA FORECAST DISCUSSION...CORRECTED
NWS PUEBLO CO
1022 AM MDT FRI SEP 13 2013
.UPDATE...
ISSUED AT 1012 AM MDT FRI SEP 13 2013
CANCELLED THE FLASH FLOOD WATCH EARLY AS THE RAIN HAS MOVED NORTH
OF EL PASO COUNTY AND ONLY SCATTERED LIGHT RAIN SHOWERS ARE
UPSTREAM OF THE REGION.
SATELLITE SHOWS ANOTHER DISTURBANCE OVER WESTERN NEW MEXICO MOVING
NORTHEAST...AND THIS DISTURBANCE WILL PASS OVER THE REGION BETWEEN
AROUND 4PM AND 8PM TODAY. HAVE SOME CONCERNS THAT THIS NEXT ROUND
OF STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL. HRRR HAS BEEN TRENDING
SLIGHTLY STRONGER WITH THESE STORMS. HOWEVER...WINDS ALOFT HAVE
BECOME SOUTHWEST AT 15 TO 30 KNOTS. STORMS WHICH DEVELOP WILL WANT
TO MOVE TO THE NORTHEAST. AM NOT TOO CONCERNED ABOUT STORMS
TRAINING OVER ONE LOCATION. HOWEVER...STILL HAVE SOME CONCERNS
THAT STORMS COULD PRODUCE SPOTTY AREAS OF LOCALLY HEAVY RAIN. IF
ONE OF THESE SPOTTY STORMS STRIKES A BURN SCAR OR OTHER
SUSCEPTIBLE AREAS...FLASH FLOOD COULD OCCUR. HRRR KEEPS BAND OF
HEAVIER PRECIPITATION JUST NORTH OF THE PALMER DIVIDE WHERE ITWANTS
TO DEVELOP CONVECTION ALONG A BOUNDARY...LIKELY THE DENVER
CYCLONE.
WHAT TO DO ABOUT WATCHES. CURRENTLY...BELIEVE THREAT FOR HEAVY
RAIN NOT SUFFICIENTLY HIGH TO WARRANT EXTENDING THE FLASH FLOOD
WATCH. HOWEVER...THE SITUATION WILL BE MONITORED.
UPDATE ISSUED AT 512 AM MDT FRI SEP 13 2013
A STRONG SOUTHEAST WIND HAS DEVELOPED ALONG THE I-25 CORRIDOR IN
EL PASO AND PUEBLO COUNTIES...AND PRECIPITATION HAS INCREASED OVER
EL PASO COUNTY WITH UP TO AN INCH PER HOUR FALLING IN A VERY
NARROW BAND ACROSS COLORADO SPRINGS. LATEST FORECAST MODELS ARE
SHOWING THE POTENTIAL FOR SOME MODERATE TO HEAVY RAIN THROUGH THE
MORNING HOURS...SO HAVE ISSUED A FLASH FLOOD WATCH THRU 18Z FOR EL
PASO AND TELLER COUNTIES WHERE SOILS ARE ALREADY SATURATED AND
THERE WILL BE A THREAT TO THE WALDO CANYON AND BLACK FOREST BURN SCARS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM MDT FRI SEP 13 2013
RAIN COVERAGE OVR THE SERN PLAINS HAS DECREASED AND HAS BECOME
LIGHTER...WHILE PCPN OVR WESTERN PORTIONS HAS INCREASED TONIGHT WITH
GENERALLY LIGHT TO SOMETIMES MODERATE RAIN BEING REPORTED OVER THE
WEST FORK COMPLEX BURN SCAR. PCPN CONTINUES TO WORK ITS WAY
NORTHWARD FROM NM SO WL KEEP POPS IN THE LIKELY CATEGORY ACRS MOST
OF THE FORECAST AREA FOR THE MORNING HOURS. ALL INDICATIONS ARE
THAT PCPN THAT FALLS OVER EL PASO AND TELLER COUNTIES...WHERE THE
MOST SATURATED CONDITIONS ARE...WL MOSTLY BE ON THE LIGHT SIDE SO
CANCELED THE FF WATCH FOR THE I-25 CORRIDOR AT 3 AM.
THE UPR LOW WL CENTERED NR THE NV...UT AND ID BORDER REGION THRU
MUCH OF THE DAY. IT THEN BEGINS TO SHIFT EASTWARD OVERNIGHT AS IT
PHASES WITH AN UPR TROF WELL TO THE NORTH. THERE WL STILL BE A
PLUME OF MSTR OVR THE FORECAST AREA...ALONG WITH GOOD CHANCES FOR
PCPN...BUT ALL MODELS ARE SHOWING EXPECTED PCPN AMOUNTS BEING ON THE
LIGHTER SIDE TODAY. THAT DOES NOT MEAN THAT THERE WILL NOT BE SOME
LOCALLY HEAVY RAIN STILL WHICH COULD AGAIN CAUSE SOME FLASH
FLOODING.
TONIGHT PCPN CHANCES LOOK LIKE THEY WILL DECREASE...ESPECIALLY OVR
ERN CO. LATE TONIGHT A SHORTWAVE TROF IS EXPECTED TO APPROACH AND
THEN MOVE INTO SWRN CO AND COULD ENHANCE PCPN CHANCES OVR SRN
AREAS...SO WL GO WITH SOME HIGH SCT POPS IN THAT AREA. THE LOCAL
WRF MODEL SHOWS THE POTENTIAL FOR SOME HEAVY RAIN OVERNIGHT ON THE
WEST FORK COMPLEX BURN SCAR...WHILE THE NAM HAS LIGHTER AMOUNTS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 349 AM MDT FRI SEP 13 2013
PRIMARY LONGER TERM ISSUES INCLUDE POPS AND TEMPERATURES. LONGER
TERM COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS SUGGEST
THAT UNSETTLED AND GENERALLY COOL CONDITIONS SHOULD PREVAIL OVER
THE FORECAST DISTRICT INTO THIS WEEKEND BEFORE WARMER AND DRIER
CONDITIONS RETURN NEXT WEEK...ESPECIALLY FROM TUESDAY ONWARD.
AT THIS TIME...IT APPEARS THAT THE CWFA AREAL COVERAGE OF
PRECIPITATION ON SATURDAY WILL BE LESS THAN HAS BEEN NOTED PREVIOUS
FEW DAYS...ALTHOUGH LOCALLY HEAVY RAIN WILL STILL BE POSSIBLE AS
PRECIPITABLE WATER VALUES NEAR 1 INCH AT TIMES AND AREAS SUCH AS
THE RECENT BURN SCARS AND LOCATIONS THAT HAVE RECEIVED HEAVY
RAINFALL DURING THE PREVIOUS FEW DAYS WILL NEED TO BE MONITORED
FOR FLOODING/FLASH FLOODING CONCERNS.
THEN AN INCREASE IN COVERAGE OF PRECIPITATION IS ANTICIPATED ON
SUNDAY AS A NORTHERLY SURGE MOVES ACROSS EASTERN SECTIONS BY
SUNDAY MORNING INCREASING FORECAST PRECIPITABLE WATER VALUES TO
AROUND 1.10 INCHES OVER PORTIONS OF THE I-25 CORRIDOR. ONCE
AGAIN...LOCALIZED FLOODING/FLASH FLOODING ISSUES MAY
ARISE...ESPECIALLY OVER RECENT BURN SCAR AND PREVIOUS HEAVY RAIN
LOCATIONS. IN ADDITION...HIGHER MOUNTAIN LOCATIONS...GENERALLY
ABOVE 12000 FEET MAY EXPERIENCE SEVERAL INCHES OF SNOW FROM
EARLY SATURDAY MORNING INTO MONDAY MORNING.
DRIER AND WARMER CONDITIONS ARE THEN EXPECTED TO DEVELOP OVER THE
FORECAST DISTRICT...ESPECIALLY FROM TUESDAY INTO THURSDAY AS
FORECAST I-25 PRECIPITATION WATER VALUES DECREASE FROM 1.4 INCHES
AS OF THURSDAY NIGHT TO AROUND 0.50 INCHES BY NEXT WEDNESDAY. IN
ADDITION...FORECAST I-25 700 MB TEMPERATURES INCREASE FROM AN 8.8C
VALUE AT 00Z FRIDAY TO A 14.7C VALUE BY 00Z THURSDAY.
FINALLY...GENERALLY LOW-GRADE GRADIENT WINDS SHOULD CONTINUE
OVER THE FORECAST DISTRICT THROUGH NEXT THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 349 AM MDT FRI SEP 13 2013
SHOULD CONTINUE TO SEE A LOT OF LOW CLOUDS AT KCOS...KPUB AND KALS
THRU THE MORNING...WITH CIGS THEN INCREASING LATE IN THE MORNING
OR IN THE EARLY AFTERNOON HOURS. THE TERMINAL SITES WL ALSO HAVE A
GOOD CHANCE FOR SHOWERS TODAY AND MAYBE A FEW TSTMS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PGW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1013 AM MDT FRI SEP 13 2013
.UPDATE...
ISSUED AT 1012 AM MDT FRI SEP 13 2013
CANCELLED THE FLASH FLOOD WATCH EARLY AS THE RAIN HAS MOVED NORTH
OF EL PASO COUNTY AND ONLY SCATTERED LIGHT RAIN SHOWERS ARE
UPSTREAM OF THE REGION.
SATELLITE SHOWS ANOTHER DISTURBANCE OVER WESTERN NEW MEXICO MOVING
NORTHEAST...AND THIS DISTURBANCE WILL PASS OVER THE REGION BETWEEN
AROUND 4PM AND 8PM TODAY. HAVE SOME CONCERNS THAT THIS NEXT ROUND
OF STORMS COULD PRODUCE LOCALLY HEAVY RAINFALL. HRRR HAS TRENDING
SLIGHTLY STRONGER WITH THESE STORMS. HOWEVER...WINDS ALOFT HAVE
BECOME SOUTHWEST AT 15 TO 30 KNOTS. STORMS WHICH DEVELOP WILL WANT
TO MOVE TO THE NORTHEAST. AM NOT TOO CONCERNED ABOUT STORMS
TRAINING OVER ONE LOCATION. HOWEVER...STILL HAVE SOME CONCERNS
THAT STORMS COULD PRODUCE SPOTTER AREAS OF LOCALLY HEAVY RAIN. IF
ONE OF THESE SPOTTY STORMS STRIKES A BURN SCAR OR OTHER SUSCEPTIBLE
AREAS...FLASH FLOOD COULD OCCUR. HRRR KEEPS BAND OF HEAVIER
PRECIPITATION JUST NORTH OF THE PALMER DIVIDE WHERE IS WANTS TO
DEVELOP CONVECTION ALONG A BOUNDARY...LIKELY THE DENVER CYCLONE.
WHAT TO DO ABOUT WATCHES. CURRENTLY...BELIEVE THREAT FOR HEAVY
RAIN NOT SUFFICIENTLY HIGH TO WARRANT EXTENDING THE FLASH FLOOD
WATCH. HOWEVER...THE SITUATION WILL BE MONITORED.
UPDATE ISSUED AT 512 AM MDT FRI SEP 13 2013
A STRONG SOUTHEAST WIND HAS DEVELOPED ALONG THE I-25 CORRIDOR IN
EL PASO AND PUEBLO COUNTIES...AND PRECIPITATION HAS INCREASED OVER
EL PASO COUNTY WITH UP TO AN INCH PER HOUR FALLING IN A VERY
NARROW BAND ACROSS COLORADO SPRINGS. LATEST FORECAST MODELS ARE
SHOWING THE POTENTIAL FOR SOME MODERATE TO HEAVY RAIN THROUGH THE
MORNING HOURS...SO HAVE ISSUED A FLASH FLOOD WATCH THRU 18Z FOR EL
PASO AND TELLER COUNTIES WHERE SOILS ARE ALREADY SATURATED AND
THERE WILL BE A THREAT TO THE WALDO CANYON AND BLACK FOREST BURN SCARS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM MDT FRI SEP 13 2013
RAIN COVERAGE OVR THE SERN PLAINS HAS DECREASED AND HAS BECOME
LIGHTER...WHILE PCPN OVR WESTERN PORTIONS HAS INCREASED TONIGHT WITH
GENERALLY LIGHT TO SOMETIMES MODERATE RAIN BEING REPORTED OVER THE
WEST FORK COMPLEX BURN SCAR. PCPN CONTINUES TO WORK ITS WAY
NORTHWARD FROM NM SO WL KEEP POPS IN THE LIKELY CATEGORY ACRS MOST
OF THE FORECAST AREA FOR THE MORNING HOURS. ALL INDICATIONS ARE
THAT PCPN THAT FALLS OVER EL PASO AND TELLER COUNTIES...WHERE THE
MOST SATURATED CONDITIONS ARE...WL MOSTLY BE ON THE LIGHT SIDE SO
CANCELED THE FF WATCH FOR THE I-25 CORRIDOR AT 3 AM.
THE UPR LOW WL CENTERED NR THE NV...UT AND ID BORDER REGION THRU
MUCH OF THE DAY. IT THEN BEGINS TO SHIFT EASTWARD OVERNIGHT AS IT
PHASES WITH AN UPR TROF WELL TO THE NORTH. THERE WL STILL BE A
PLUME OF MSTR OVR THE FORECAST AREA...ALONG WITH GOOD CHANCES FOR
PCPN...BUT ALL MODELS ARE SHOWING EXPECTED PCPN AMOUNTS BEING ON THE
LIGHTER SIDE TODAY. THAT DOES NOT MEAN THAT THERE WILL NOT BE SOME
LOCALLY HEAVY RAIN STILL WHICH COULD AGAIN CAUSE SOME FLASH
FLOODING.
TONIGHT PCPN CHANCES LOOK LIKE THEY WILL DECREASE...ESPECIALLY OVR
ERN CO. LATE TONIGHT A SHORTWAVE TROF IS EXPECTED TO APPROACH AND
THEN MOVE INTO SWRN CO AND COULD ENHANCE PCPN CHANCES OVR SRN
AREAS...SO WL GO WITH SOME HIGH SCT POPS IN THAT AREA. THE LOCAL
WRF MODEL SHOWS THE POTENTIAL FOR SOME HEAVY RAIN OVERNIGHT ON THE
WEST FORK COMPLEX BURN SCAR...WHILE THE NAM HAS LIGHTER AMOUNTS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 349 AM MDT FRI SEP 13 2013
PRIMARY LONGER TERM ISSUES INCLUDE POPS AND TEMPERATURES. LONGER
TERM COMPUTER SIMULATIONS AND FORECAST MODEL SOUNDINGS SUGGEST
THAT UNSETTLED AND GENERALLY COOL CONDITIONS SHOULD PREVAIL OVER
THE FORECAST DISTRICT INTO THIS WEEKEND BEFORE WARMER AND DRIER
CONDITIONS RETURN NEXT WEEK...ESPECIALLY FROM TUESDAY ONWARD.
AT THIS TIME...IT APPEARS THAT THE CWFA AREAL COVERAGE OF
PRECIPITATION ON SATURDAY WILL BE LESS THAN HAS BEEN NOTED PREVIOUS
FEW DAYS...ALTHOUGH LOCALLY HEAVY RAIN WILL STILL BE POSSIBLE AS
PRECIPITABLE WATER VALUES NEAR 1 INCH AT TIMES AND AREAS SUCH AS
THE RECENT BURN SCARS AND LOCATIONS THAT HAVE RECEIVED HEAVY
RAINFALL DURING THE PREVIOUS FEW DAYS WILL NEED TO BE MONITORED
FOR FLOODING/FLASH FLOODING CONCERNS.
THEN AN INCREASE IN COVERAGE OF PRECIPITATION IS ANTICIPATED ON
SUNDAY AS A NORTHERLY SURGE MOVES ACROSS EASTERN SECTIONS BY
SUNDAY MORNING INCREASING FORECAST PRECIPITABLE WATER VALUES TO
AROUND 1.10 INCHES OVER PORTIONS OF THE I-25 CORRIDOR. ONCE
AGAIN...LOCALIZED FLOODING/FLASH FLOODING ISSUES MAY
ARISE...ESPECIALLY OVER RECENT BURN SCAR AND PREVIOUS HEAVY RAIN
LOCATIONS. IN ADDITION...HIGHER MOUNTAIN LOCATIONS...GENERALLY
ABOVE 12000 FEET MAY EXPERIENCE SEVERAL INCHES OF SNOW FROM
EARLY SATURDAY MORNING INTO MONDAY MORNING.
DRIER AND WARMER CONDITIONS ARE THEN EXPECTED TO DEVELOP OVER THE
FORECAST DISTRICT...ESPECIALLY FROM TUESDAY INTO THURSDAY AS
FORECAST I-25 PRECIPITATION WATER VALUES DECREASE FROM 1.4 INCHES
AS OF THURSDAY NIGHT TO AROUND 0.50 INCHES BY NEXT WEDNESDAY. IN
ADDITION...FORECAST I-25 700 MB TEMPERATURES INCREASE FROM AN 8.8C
VALUE AT 00Z FRIDAY TO A 14.7C VALUE BY 00Z THURSDAY.
FINALLY...GENERALLY LOW-GRADE GRADIENT WINDS SHOULD CONTINUE
OVER THE FORECAST DISTRICT THROUGH NEXT THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 349 AM MDT FRI SEP 13 2013
SHOULD CONTINUE TO SEE A LOT OF LOW CLOUDS AT KCOS...KPUB AND KALS
THRU THE MORNING...WITH CIGS THEN INCREASING LATE IN THE MORNING
OR IN THE EARLY AFTERNOON HOURS. THE TERMINAL SITES WL ALSO HAVE A
GOOD CHANCE FOR SHOWERS TODAY AND MAYBE A FEW TSTMS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PGW
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
944 AM MDT FRI SEP 13 2013
.UPDATE...
&&
.SHORT TERM...ONE BATCH OF LIGHT TO MODERATE RAIN IS MOVING
THROUGH CWA THIS MORNING AND THEN LOOKS LIKE ANOTHER WAVE FOR
LATER THIS AFTERNOON AND EVENING COMING IN FROM NEW MEXICO.
THE INITIAL RAINFALL THIS MORNING IS MORE LIGHT TO MODERATE RAIN
WITH RATES GENERALLY A THIRD OF AN INCH OR LESS IN ONE HOUR. LOOKS
LIKE A BREAK IN THE RAIN LATE THIS AM AND EARLY AFTERNOON UNTIL
THE NEXT BATCH OF RAIN MOVES IN. WITH THE BREAK...COULD BE SOME
BREAKS IN THE CLOUDS AND SOME HEATING WHICH COULD LEAD TO HEAVIER
RAIN AND ISOLATED THUNDERSTORMS. LATEST RAP AND HRRR DOES SHOW
SOME ECHO TRAINING OVER THE FOOTHILLS AND DENVER AREA. BASED ON
THIS HAVE DECIDED TO EXTEND THE FLASH FLOOD WATCH UNTIL 9 PM LOCAL
TIME THIS EVENING. OTHER THAN THAT NOT MANY CHANGES PLANNED.
.AVIATION...A BREAK IS COMING SO EXPECT CEILINGS/VSBYS LIFT A BIT
OVER THE NEXT FEW HOURS UNTIL LATER THIS AFTERNOON WHEN SHOWERS
REDEVELOPING IN IFR CIGS/VSBYS.
&&
.HYDROLOGY...FLASH FLOOD WATCH WILL BE EXTENDED THROUGH THIS
EVENING UNTIL 9 PM LOCAL TIME WITH MORE HEAVIER STORMS EXPECTED
LATER THIS AFTERNOON AND EVENING. ANY ADDITIONAL HEAVIER RAIN WILL
RESULT IN MORE FLASH FLOODING IN AREAS ALREADY SATURATED WITH RAIN.
THERE WILL BE A BREAK IN THE RAIN FROM MID MORNING UNTIL AT LEAST
EARLY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 258 AM MDT FRI SEP 13 2013/
SHORT TERM...A SHORTWAVE TROUGH WILL PUSH OVER THE STATE TODAY TO
DECREASE RAIN AFTER THE 3+ DAYS OF RECORD BREAKING RAINFALL ACROSS
THE FRONT RANGE. RAIN AMOUNTS ARE DECREASING ACROSS THE FOOTHILLS
AND METRO AREAS...BUT THE GROUND IS SO SATURATED THAT ANY
ADDITIONAL RAINFALL CAN AND WILL CONTINUE TO CAUSE PROBLEMS. SO
EVEN THOUGH THE FORECAST IS DECREASING RAIN...HAVE EXTENDED THE
FLASH FLOOD WATCH UNTIL NOON TODAY. RAIN IS INCREASING OVER THE
EASTERN PLAINS OF COLORADO...BUT THEY HAVE NOT RECEIVED AS MUCH
RAIN OVER THE LAST FEW DAYS AND THEREFORE WILL NOT INCLUDE THEM IN
THE WATCH. OVERALL...EXPECT ANOTHER QUARTER TO HALF AN INCH OF
WATER TODAY...WITH AREAS ALONG THE FOOTHILLS SEEING POTENTIALLY
ANOTHER INCH. TEMPERATURES WILL AGAIN NOT CHANGE MUCH THROUGH THE
DAY...BUT AS THE MOISTURE MOVES NORTH AND OUT OF THE AREA...SOME
MORE BREAKS IN THE CLOUDS ARE EXPECTED TO LET TEMPS WARM A FEW
DEGREES OVER YESTERDAYS HIGHS...BUT STILL BELOW AVERAGE FOR THIS
TIME OF YEAR.
THIS EVENING INTO THE NIGHT SHOULD SHOW DRAMATIC DECREASE IN
PRECIPITATION AND CLOUD COVER. THIS WILL ALLOW TEMPERATURES TO
COOL OVERNIGHT AND MAY ALLOW FOR AREAS OF FOG. NOT TOTALLY
CONFIDENT ON CLOUD COVER HOWEVER...SO WILL NOT INTRODUCE INTO THE
FORECAST JUST YET.
LONG TERM...MODELS HAVE THE UPPER TROUGH WEST OF COLORADO
SATURDAY THROUGH SUNDAY EVENING. THE FLOW ALOFT IS SOUTHWESTERLY
FOR THE CWA. THE WEAK UPWARD SYNOPTIC SCALE ENERGY IS PROGGED TO
CONTINUE ACCORDING TO THE QG VERTICAL VELOCITY FIELDS. THE
BOUNDARY LAYER WINDS ARE WEAK DOWNSLOPING SATURDAY. A COLD FRONT
AND UPSLOPE ARE PROGGED INTO THE PLAINS AND FOOTHILLS SATURDAY
EVENING. THE UPSLOPE IS PROGGED TO CONTINUE THROUGH SUNDAY
EVENING. FOR MOISTURE...SATURDAY DRIES OUT A BIT...BUT SUNDAY HAS
MORE MOISTURE. PRECIPITABLE WATER VALUES ARE PROGGED IN THE 0.80
TO 0.90 INCH RANGE OVER THE WESTERN PLAINS SATURDAY...THEN 0.90 TO
1.00 INCH SUNDAY. THE FURTHER EASTERN PLAINS ARE MORE MOIST
SATURDAY...BUT THE SAME ON SUNDAY. DEW POINT PROGGS HAVE MID 40S F
READINGS OVER THE WESTERN CWA TO LOWER 60S F OVER THE FAR EAST
THROUGH THE FOUR PERIODS. THE QPF FIELDS SHOW SATURDAY MORNING TO
BE DRY OVER THE CWA...THEN AMOUNTS INCREASE SATURDAY AFTERNOON.
THERE IS SOME OVER THE CWA SATURDAY NIGHT...THEN SUNDAY`S
MEASURABLE RAINFALL INCREASES OVER SATURDAY`S. THERE IS SOME
FAIRLY DECENT CAPE PROGGED OVER THE CWA LATE DAY SATURDAY...THEN
MUCH LESS SUNDAY...AND ITS JUST OVER THE MOUNTAINS. FOR POPS...
WILL KEEP THEM PRETTY HIGH ESPECIALLY FOR THE AFTERNOONS AND
EVENINGS. BETTER CONVECTION LATE DAY SATURDAY...MORE STABLE WITH
UPSLOPE FOR LATE DAY SUNDAY. FOR TEMPERATURES...SATURDAY`S HIGHS
ARE 3-6 C WARMER THAN FRIDAY`S. SUNDAY`S HIGHS COOL BACK OFF 4-8C
FROM SATURDAY`S. FOR THE LATER DAYS...MONDAY THROUGH THURSDAY
..MODELS HAVE FLAT UPPER RIDGING INTO WEDNESDAY. AN UPPER TROUGH
OVER THE NORTHERN U.S. BORDER WILL PUSH EASTWARD LATER WEDNESDAY
INTO THURSDAY JUST BRUSHING COLORADO. MOISTURE WILL BE PRETTY
SPARSE AND TEMPERATURES SHOULD BE RIGHT AROUND SEASONAL NORMALS.
AVIATION...CONTINUED LOW CEILINGS AND VISIBILITIES WITH RAIN AND
STRATUS WILL BE THE MAIN STORY THROUGH 12Z. IMPROVEMENTS ARE
THEN EXPECTED AS SLIGHTLY DRIER AIR MAKES ITS WAY INTO THE AREA
FROM THE SOUTH. SHOULD SEE RAIN END BY 00Z WITH CEILINGS LIFTING
TO VFR. CONTINUED EASTERLY TO SOUTHEASTERLY SURFACE WINDS...LESS
THAN 12 KNOTS. AREAS OF FOG A POSSIBILITY TONIGHT...BUT CONFIDENCE
IS LOW SO WILL NOT PUT IN THE TAFS FOR NOW.
HYDROLOGY...MULTIPLE FLOOD AND FLASH FLOOD WARNINGS IN EFFECT
WITH SIGNIFICANT IMPACTS. MAJOR RELIEF NOT EXPECTED UNTIL LATE
MORNING WITH SHOWERS EXPECT TO REMAIN UNTIL 00Z...BUT AT LESS
INTENSITY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH EXTENDED UNTIL 9 PM MDT TODAY FOR
COZ035-036-038>041- 043.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RJK
AVIATION...RTG
AREA FORECAST DISCUSSION
NWS MIAMI FL
843 PM EDT SAT SEP 14 2013
.UPDATE...
CONDITIONS ARE QUIETING DOWN ACROSS SOUTH FLORIDA THIS EVENING.
CURRENT POPS ARE IN GOOD SHAPE. THERE ARE SOME SHOWERS AND A FEW
THUNDERSTORMS THAT WILL PROBABLY AFFECT THE ATLANTIC COASTAL
WATERS TONIGHT, BUT MOST SHOULD REMAIN WELL OFFSHORE. NO MAJOR
CHANGES MADE TO THE FORECAST WITH THIS UPDATE.
&&
.PREV DISCUSSION... /ISSUED 720 PM EDT SAT SEP 14 2013/
AVIATION...
THE WEATHER WILL BE DRY OVER ALL OF THE TAF SITES TONIGHT...AS
THE WINDS WILL BE LESS THAN 5 KNOTS FROM THE EAST. THE WINDS WILL
THEN INCREASE TO AROUND 10 KNOTS ON SUNDAY FROM THE EAST AT ALL OF
SOUTH FLORIDA TAF SITES ALONG WITH SOME SHOWERS IN THE MORNING AND
THUNDERSTORMS IN THE AFTERNOON. SO WILL ADD VCSH TO ALL OF THE TAF
SITES AFTER 14Z AND VCTS AFTER 17Z...EXCEPT FOR KAPF TAF SITE
WHERE VCTS WILL BE PUT IN AFTER 15Z ON SUNDAY. THE CEILING AND VIS
WILL ALSO REMAIN IN THE VFR CONDITIONS TONIGHT INTO SUNDAY...AS
THE TIMING OF THE SHOWERS AND THUNDERSTORMS ON SUNDAY IS NOT KNOWN
AT THIS TIME.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 236 PM EDT SAT SEP 14 2013/
SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE REGION WILL ESTABLISH MODEST
BUT DEEP EASTERLY FLOW OVER SOUTH FLORIDA FOR MUCH OF NEXT WEEK.
THIS WILL ADVECT TROPICAL MOISTURE INTO THE AREA...RESULTING IN
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
SAL APPEARS TO BE SUCCESSFULLY SUPPRESSING CONVECTION TODAY OVER
MOST OF SOUTH FLORIDA. EASTERLY FLOW IS A BIT STRONGER TODAY THAN
YESTERDAY...SO GULF BREEZE HAS BEEN SLOW TO DEVELOP...WHILE
ATLANTIC BREEZE IS NOW INLAND OF METRO EAST COAST METRO AREAS.
ISOLATED TO SCATTERED CONVECTION IS STILL EXPECTED ALONG AND AHEAD
OF EITHER SEA-BREEZE...WITH GREATEST COVERAGE NEAR/WEST OF LAKE
OKEECHOBEE...WHERE LOW/MID-LEVELS ARE LEAST DRY AND DUST LAYER IS
LESS SIGNIFICANT. 18Z VSB SATELLITE ALREADY DEPICTS SIGNIFICANT CU
FIELD IN THIS REGION...AND HRRR FORECAST COMPOSITE REFLECTIVITY IS
MORE IMPRESSIVE THAN WAS INDICTED YESTERDAY AT THIS TIME. EXPECT
ACTIVITY TO HAVE SLOW SOUTHWARD DRIFT...THOUGH WITH LOW PWATS
FLOODING IS NOT A SIGNIFICANT THREAT. FORECAST AND 12Z SOUNDING
WERE NOT PARTICULARLY FAVORABLE FOR ANYTHING STRONGER THAN TYPICAL
SUMMERTIME CONVECTION...SO WILL LEAVE HWO MENTIONING FREQUENT
CLOUD-TO-GROUND LIGHTNING AS MAIN THREAT. CONVECTION WILL
DIURNALLY WANE.
UPPER-LEVEL TROUGH OVER EASTERN CONUS LIFTS NORTHWARD
TONIGHT...ALLOWING DEEP LAYER HIGH PRESSURE TO BUILD OVER THE
SOUTHEAST UNITED STATES AND ADJACENT ATLANTIC. WITH THE RIDGE AXIS
NORTH OF SOUTH FLORIDA...DEEP EASTERLY FLOW WILL
ESTABLISH...USHERING IN GREATER MOISTURE AND CAUSING AN UPWARD-
TREND IN POPS SUNDAY INTO MONDAY. SCATTERED TO PERHAPS NUMEROUS
CONVECTION IS EXPECTED BOTH AFTERNOONS. TEMPERATURES WILL BE
SOMEWHAT REGULATED BY THE INCREASE IN PCPN/CLOUDS...BUT OVERALL
WILL REMAIN NEAR NORMAL FOR MID-SEPTEMBER.
LONG TERM /TUESDAY THROUGH FRIDAY...
SIMILAR SYNOPTIC CONDITIONS WILL PERSIST THROUGH MUCH OF THE
PERIOD WITH MODELS PROJECTING LIKELY POPS. FOR NOW...CAPPING RAIN
CHANCES AT THIS TIME IN THE 40-50% RANGE. IN THE LATTER HALF OF
THE WEEK LOW LEVEL RIDGE PERSISTS AND WITH MOISTURE LEVELS
REMAINING CLOSE TO NORMAL RAIN CHANCES ARE FORECAST TO BE NEAR
CLIMO WITH DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS FORECAST
WEDNESDAY THROUGH FRIDAY. AS IN THE SHORT RANGE...TEMPERATURE
PATTERN OF NEARLY NORMAL DAYTIME HIGHS AND ABOVE NORMAL OVERNIGHT
LOWS WILL PERSIST.
MARINE...
EAST WINDS OF 5-15 KTS WILL PREVAIL FOR MOST OF THE NEXT 5 DAYS.
SEAS WILL BE 3 FEET OR LESS. SCATTERED THUNDERSTORMS SHOULD BE
PRESENT OVER THE WATERS BEGINNING SUNDAY AFTERNOON AND CONTINUE
THROUGH AT LEAST MID-WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 89 78 89 / 10 40 30 50
FORT LAUDERDALE 79 89 80 90 / 20 40 30 50
MIAMI 79 90 79 89 / 20 40 30 50
NAPLES 76 91 76 91 / 20 40 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
720 PM EDT SAT SEP 14 2013
.UPDATE...
THE WEATHER WILL BE DRY OVER ALL OF THE TAF SITES TONIGHT...AS THE
WINDS WILL BE LESS THAN 5 KNOTS FROM THE EAST. THE WINDS WILL THEN
INCREASE TO AROUND 10 KNOTS ON SUNDAY FROM THE EAST AT ALL OF
SOUTH FLORIDA TAF SITES ALONG WITH SOME SHOWERS IN THE MORNING AND
THUNDERSTORMS IN THE AFTERNOON. SO WILL ADD VCSH TO ALL OF THE TAF
SITES AFTER 14Z AND VCTS AFTER 17Z...EXCEPT FOR KAPF TAF SITE
WHERE VCTS WILL BE PUT IN AFTER 15Z ON SUNDAY. THE CEILING AND VIS
WILL ALSO REMAIN IN THE VFR CONDITIONS TONIGHT INTO SUNDAY...AS
THE TIMING OF THE SHOWERS AND THUNDERSTORMS ON SUNDAY IS NOT KNOWN
AT THIS TIME.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 236 PM EDT SAT SEP 14 2013/
SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE REGION WILL ESTABLISH MODEST
BUT DEEP EASTERLY FLOW OVER SOUTH FLORIDA FOR MUCH OF NEXT WEEK.
THIS WILL ADVECT TROPICAL MOISTURE INTO THE AREA...RESULTING IN
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
SAL APPEARS TO BE SUCCESSFULLY SUPPRESSING CONVECTION TODAY OVER
MOST OF SOUTH FLORIDA. EASTERLY FLOW IS A BIT STRONGER TODAY THAN
YESTERDAY...SO GULF BREEZE HAS BEEN SLOW TO DEVELOP...WHILE
ATLANTIC BREEZE IS NOW INLAND OF METRO EAST COAST METRO AREAS.
ISOLATED TO SCATTERED CONVECTION IS STILL EXPECTED ALONG AND AHEAD
OF EITHER SEA-BREEZE...WITH GREATEST COVERAGE NEAR/WEST OF LAKE
OKEECHOBEE...WHERE LOW/MID-LEVELS ARE LEAST DRY AND DUST LAYER IS
LESS SIGNIFICANT. 18Z VSB SATELLITE ALREADY DEPICTS SIGNIFICANT CU
FIELD IN THIS REGION...AND HRRR FORECAST COMPOSITE REFLECTIVITY IS
MORE IMPRESSIVE THAN WAS INDICTED YESTERDAY AT THIS TIME. EXPECT
ACTIVITY TO HAVE SLOW SOUTHWARD DRIFT...THOUGH WITH LOW PWATS
FLOODING IS NOT A SIGNIFICANT THREAT. FORECAST AND 12Z SOUNDING
WERE NOT PARTICULARLY FAVORABLE FOR ANYTHING STRONGER THAN TYPICAL
SUMMERTIME CONVECTION...SO WILL LEAVE HWO MENTIONING FREQUENT
CLOUD-TO-GROUND LIGHTNING AS MAIN THREAT. CONVECTION WILL
DIURNALLY WANE.
UPPER-LEVEL TROUGH OVER EASTERN CONUS LIFTS NORTHWARD
TONIGHT...ALLOWING DEEP LAYER HIGH PRESSURE TO BUILD OVER THE
SOUTHEAST UNITED STATES AND ADJACENT ATLANTIC. WITH THE RIDGE AXIS
NORTH OF SOUTH FLORIDA...DEEP EASTERLY FLOW WILL
ESTABLISH...USHERING IN GREATER MOISTURE AND CAUSING AN UPWARD-
TREND IN POPS SUNDAY INTO MONDAY. SCATTERED TO PERHAPS NUMEROUS
CONVECTION IS EXPECTED BOTH AFTERNOONS. TEMPERATURES WILL BE
SOMEWHAT REGULATED BY THE INCREASE IN PCPN/CLOUDS...BUT OVERALL
WILL REMAIN NEAR NORMAL FOR MID-SEPTEMBER.
LONG TERM /TUESDAY THROUGH FRIDAY...
SIMILAR SYNOPTIC CONDITIONS WILL PERSIST THROUGH MUCH OF THE
PERIOD WITH MODELS PROJECTING LIKELY POPS. FOR NOW...CAPPING RAIN
CHANCES AT THIS TIME IN THE 40-50% RANGE. IN THE LATTER HALF OF
THE WEEK LOW LEVEL RIDGE PERSISTS AND WITH MOISTURE LEVELS
REMAINING CLOSE TO NORMAL RAIN CHANCES ARE FORECAST TO BE NEAR
CLIMO WITH DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS FORECAST
WEDNESDAY THROUGH FRIDAY. AS IN THE SHORT RANGE...TEMPERATURE
PATTERN OF NEARLY NORMAL DAYTIME HIGHS AND ABOVE NORMAL OVERNIGHT
LOWS WILL PERSIST.
AVIATION...
THE EAST AND WEST COAST SEA-BREEZES HAVE FORMED. FOR THE EAST COAST
TERMINALS SHOWERS/THUNDERSTORMS WILL LIKELY REMAIN WESTWARD OF THE
TERMINALS WITH VCSH ASSIGNED ALTHOUGH ACTIVE CONVECTION IS NOT
EXPECTED TODAY. FOR TERMINAL KAPF VCTS ASSIGNED AT 19Z...ALTHOUGH
THUNDERSTORMS COULD BE INLAND AND EAST OF THE TERMINAL WHICH IS
INDICATED IN LATEST MESO-SCALE MODEL GUIDANCE. BUT GIVEN THE
UNCERTAINTIES VCTS ASSIGNED. MAINLY VFR CONDITIONS EXPECTED THIS
AFTERNOON ALL TERMINALS...BUT ANY OCCURRENCE OF SHOWERS OR A
THUNDERSTORM COULD RESULT IN BRIEF SUB-VFR CONDITIONS.
MARINE...
EAST WINDS OF 5-15 KTS WILL PREVAIL FOR MOST OF THE NEXT 5 DAYS.
SEAS WILL BE 3 FEET OR LESS. SCATTERED THUNDERSTORMS SHOULD BE
PRESENT OVER THE WATERS BEGINNING SUNDAY AFTERNOON AND CONTINUE
THROUGH AT LEAST MID-WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 89 78 89 / 10 40 30 50
FORT LAUDERDALE 79 89 80 90 / 20 40 30 50
MIAMI 79 90 79 89 / 20 40 30 50
NAPLES 76 91 76 91 / 10 40 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...23/SK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
153 PM EDT FRI SEP 13 2013
.AVIATION...
A MUCH DRIER BOUNDARY LAYER COMBINED WITH A THIN VEIL OF SAHARAN
DUST IS INHIBITING SHRA/TSRA DEVELOPMENT THUS FAR THIS AFTERNOON.
LATEST SATELLITE TRENDS SHOW A VERY MEAGER CU FIELD WITH SEA
BREEZES AT BOTH COASTS BEGINNING TO DEVELOP. STILL BELIEVE ANY
CONVECTION THAT DOES DEVELOP SHOULD BE DRIVEN BY SEA BREEZE
INTERACTIONS AND SHOULD STAY GENERALLY INLAND OF THE TAF SITES.
KEPT VCTS AT ALL SITES THROUGH 00Z-01Z BUT STILL RATHER UNCERTAIN
IN THE OVERALL COVERAGE.
&&
.PREV DISCUSSION... /ISSUED 1005 AM EDT FRI SEP 13 2013/
UPDATE...
LITTLE IN ONGOING FORECAST THIS MORNING. 12Z RAOB ANALYSIS SHOWS
IMPRESSIVE LOW-MID-LVL DRY AIR / SAL THAT IS IMPACTING AT LEAST
SOUTHERN CWA TODAY. AS A RESULT...PWAT IS ONLY 1.50. WITH THIS
AMOUNT OF DRY AIR AND POSSIBLY DUST INTERFERE...CONVECTIVE
INITIATION POTENTIAL IS HIGHLY UNCERTAIN...PARTICULARLY WITH LACK
OF OVERALL DYNAMICS. STILL...SEA BREEZE CIRCULATIONS COULD BE
SUFFICIENT FOR DEVELOPMENT OF TSTMS MAINLY OVER NORTHERN INTERIOR.
SYNOPTIC MODELS REFLECT THIS OCCURRING...BUT HRRR DEPICTS ON
MODEST DEVELOPMENT. POPS RMN IN SCATTERED RANGE
INTERIOR...ISOLATED ALONG THE COASTS/WATERS. DOWNBURSTS ARE
FAVORED IN ANY STRONG CONVECTION...SO GUSTY WINDS CANT BE RULED
OUT. SLOW STORM MOTION COULD ALSO LEAD TO SIGNIFICANT RAINFALL
TOTALS...ALTHOUGH STORM CHANCES ARE BEST OVER NON-URBAN/FLOOD
PRONE AREAS.
PREV DISCUSSION... /ISSUED 355 AM EDT FRI SEP 13 2013/
DISCUSSION...
THE MAIN SYNOPTIC FEATURES ACROSS THE REGION INCLUDE WEAK HIGH
PRESSURE ACROSS SOUTH FLORIDA AND ADJACENT WATERS...A CUT-OFF UPPER
LEVEL LOW OFF THE GEORGIA COASTLINE AND A PLUME OF DEEP LAYER
MOISTURE EXTENDING FROM NEAR LAKE OKEECHOBEE THEN NORTHEASTWARD INTO
THE ADJACENT ATLANTIC WATERS. THESE FEATURES RESULTED IN CONVECTION
ACROSS NORTHEASTERN PALM BEACH COUNTY AND THE ADJACENT ATLANTIC
WATERS DURING THE EARLY MORNING HOURS WITH LINGERING SHOWERS AND
THUNDERSTORMS JUST TO THE EAST OF PALM BEACH COUNTY.
THERE IS SOME SAHARAN AIR LAYER DUST IN THE REGION WITH
RECENT GUIDANCE SUGGESTING THE MOST CONCENTRATED PART WILL LIKELY
REMAIN JUST SOUTH OF SOUTH FLORIDA ALTHOUGH SOME LESS CONCENTRATED
DUST AND DRIER AIR COULD IMPACT THE SOUTHERN HALF OR THIRD OF THE
PENINSULA TODAY. HARD TO SAY HOW MUCH IMPACT THIS MAY HAVE ON
AFTERNOON CONVECTION...ALTHOUGH LATEST GUIDANCE SUGGESTS THAT
MAYBE ONLY ISOLATED ACTIVITY AT BEST MAY BE EXPECTED ACROSS THE
SOUTHERN PORTIONS OF THE PENINSULA AND ADJACENT WATERS . BUT GIVEN
THE UNCERTAINTIES...THE CURRENT FORECAST INDICATES ONLY ISOLATED
SHOWERS/THUNDERSTORMS IN THE SOUTHERN MOST ZONE IN THE PENINSULA
OTHERWISE ISOLATED TO SCATTERED ACTIVITY FOR THE REMAINING EAST
AND WEST COAST METRO AREAS WITH SCATTERED ACTIVITY FORECAST
INTERIOR REGIONS.
TONIGHT INTO SATURDAY A COLD FRONT THAT IS CURRENTLY JUST NORTH OF
THE CAROLINAS IS FORECAST TO MOVE INTO NORTH FLORIDA ON SATURDAY
AND BECOME DIFFUSE THE REMAINDER OF THE WEEKEND. THE
AFOREMENTIONED CUT-OFF UPPER LEVEL LOW IS FORECAST TO QUICKLY LIFT
OFF TO THE NORTHEAST TODAY AND TONIGHT AND GET MERGED INTO A LARGE
AMPLITUDE UPPER LEVEL TROUGH FORECAST TO DIG INTO THE EASTERN SEA-
BOARD ON SATURDAY. FOR SATURDAY...WITH LINGERING MOISTURE ACROSS
THE REGION AND EASTERLY FLOW RETURNING MAINLY AFTERNOON ISOLATED
TO SCATTERED SHOWERS/THUNDERSTORMS ARE FORECAST WITH ISOLATED
ACTIVITY EXPECTED ACROSS THE EASTERN THIRD OF THE PENINSULA AND
SCATTERED ACROSS THE REMAINDER OF THE PENINSULA. BY SUNDAY THE
LARGE AMPLITUDE UPPER LEVEL TROUGH DIGS INTO THE SOUTHEAST U.S.
AND INTO THE REGION. THAT COUPLED WITH AN ADDITIONAL INFLUX OF
MOISTURE FROM THE ATLANTIC WATERS IS FORECAST TO RESULT IN
AFTERNOON SCATTERED SHOWERS AND THUNDERSTORMS. SIMILAR SYNOPTIC
CONDITIONS WILL PERSIST THROUGH THE EARLY PART OF THE WEEK. IN THE
LATER HALF OF THE WEEK ALTHOUGH MID TO UPPER LEVEL RIDGING BUILDS
INTO THE REGION...DEEP LAYERED MOISTURE IS FORECAST TO PREVAIL
ACROSS THE AREA WITH DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS
FORECAST WEDNESDAY THROUGH FRIDAY.
MARINE...
WINDS ACROSS THE REGIONAL WATERS TODAY WILL BE LIGHT AND COULD AT
TIMES BECOME LIGHT AND VARIABLE. BY SATURDAY EASTERLY FLOW WILL
RETURN IN THE 6 TO 10 KNOT RANGE AND THEN BY MONDAY THROUGH MID-
WEEK MODERATE EASTERLY FLOW IN THE 10 TO 15 KNOT RANGE IS
FORECAST. TODAY THROUGH THE WEEKEND SEAS ACROSS THE GULF AND
ATLANTIC WATERS ARE EXPECTED TO BE 2 FEET OR LESS AND MONDAY
THROUGH NEXT WEEK SEAS FROM 2 TO 3 FEET ARE POSSIBLE ACROSS THE
ATLANTIC WATERS AND THE OFF SHORE GULF WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 89 78 89 / 20 20 10 40
FORT LAUDERDALE 79 91 80 91 / 10 20 10 40
MIAMI 77 91 79 90 / 10 20 10 40
NAPLES 75 92 76 93 / 10 20 10 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...23/SK
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
1005 AM EDT FRI SEP 13 2013
.UPDATE...
LITTLE IN ONGOING FORECAST THIS MORNING. 12Z RAOB ANALYSIS SHOWS
IMPRESSIVE LOW-MID-LVL DRY AIR / SAL THAT IS IMPACTING AT LEAST
SOUTHERN CWA TODAY. AS A RESULT...PWAT IS ONLY 1.50. WITH THIS
AMOUNT OF DRY AIR AND POSSIBLY DUST INTERFERE...CONVECTIVE
INITIATION POTENTIAL IS HIGHLY UNCERTAIN...PARTICULARLY WITH LACK
OF OVERALL DYNAMICS. STILL...SEA BREEZE CIRCULATIONS COULD BE
SUFFICIENT FOR DEVELOPMENT OF TSTMS MAINLY OVER NORTHERN INTERIOR.
SYNOPTIC MODELS REFLECT THIS OCCURRING...BUT HRRR DEPICTS ON
MODEST DEVELOPMENT. POPS RMN IN SCATTERED RANGE
INTERIOR...ISOLATED ALONG THE COASTS/WATERS. DOWNBURSTS ARE
FAVORED IN ANY STRONG CONVECTION...SO GUSTY WINDS CANT BE RULED
OUT. SLOW STORM MOTION COULD ALSO LEAD TO SIGNIFICANT RAINFALL
TOTALS...ALTHOUGH STORM CHANCES ARE BEST OVER NON-URBAN/FLOOD
PRONE AREAS.
&&
.PREV DISCUSSION... /ISSUED 731 AM EDT FRI SEP 13 2013/
AVIATION...
TERMINAL KTMB COULD HAVE PERIODS OF IFR CONDITIONS DUE TO FOG
THROUGH THE 12Z-13Z TIME FRAME BUT SHOULD RAPIDLY DISSIPATE WITH
DAY TIME HEATING. OTHERWISE...MAINLY VFR CONDITIONS ARE EXPECTED
TO PREVAIL FOR THE REMAINING TERMINALS.
THERE IS SOME SAHARAN AIR LAYER DUST IN THE REGION COMING OFF THE
ATLANTIC WATERS. RECENT GUIDANCE SUGGESTS THE MOST CONCENTRATED PART
COULD REMAIN JUST SOUTH OF SOUTH FLORIDA ALTHOUGH SOME LESS
CONCENTRATED DUST AND DRIER AIR COULD IMPACT THE SOUTHERN HALF OR
THIRD OF THE PENINSULA TODAY. HARD TO SAY HOW MUCH IMPACT THIS MAY
HAVE ON AFTERNOON CONVECTION. GIVEN THE UNCERTAINTIES...THE CURRENT
TAF`S FOR ALL TERMINALS INDICATE VCTS IN THE 17Z-18Z TIME FRAME.
COULD BE A LITTLE SOONER FOR KPBI WITH A LINGERING BOUNDARY FROM
CONVECTION EARLIER THIS MORNING.
PREV DISCUSSION... /ISSUED 355 AM EDT FRI SEP 13 2013/
DISCUSSION...
THE MAIN SYNOPTIC FEATURES ACROSS THE REGION INCLUDE WEAK HIGH
PRESSURE ACROSS SOUTH FLORIDA AND ADJACENT WATERS...A CUT-OFF UPPER
LEVEL LOW OFF THE GEORGIA COASTLINE AND A PLUME OF DEEP LAYER
MOISTURE EXTENDING FROM NEAR LAKE OKEECHOBEE THEN NORTHEASTWARD INTO
THE ADJACENT ATLANTIC WATERS. THESE FEATURES RESULTED IN CONVECTION
ACROSS NORTHEASTERN PALM BEACH COUNTY AND THE ADJACENT ATLANTIC
WATERS DURING THE EARLY MORNING HOURS WITH LINGERING SHOWERS AND
THUNDERSTORMS JUST TO THE EAST OF PALM BEACH COUNTY.
THERE IS SOME SAHARAN AIR LAYER DUST IN THE REGION WITH
RECENT GUIDANCE SUGGESTING THE MOST CONCENTRATED PART WILL LIKELY
REMAIN JUST SOUTH OF SOUTH FLORIDA ALTHOUGH SOME LESS CONCENTRATED
DUST AND DRIER AIR COULD IMPACT THE SOUTHERN HALF OR THIRD OF THE
PENINSULA TODAY. HARD TO SAY HOW MUCH IMPACT THIS MAY HAVE ON
AFTERNOON CONVECTION...ALTHOUGH LATEST GUIDANCE SUGGESTS THAT
MAYBE ONLY ISOLATED ACTIVITY AT BEST MAY BE EXPECTED ACROSS THE
SOUTHERN PORTIONS OF THE PENINSULA AND ADJACENT WATERS . BUT GIVEN
THE UNCERTAINTIES...THE CURRENT FORECAST INDICATES ONLY ISOLATED
SHOWERS/THUNDERSTORMS IN THE SOUTHERN MOST ZONE IN THE PENINSULA
OTHERWISE ISOLATED TO SCATTERED ACTIVITY FOR THE REMAINING EAST
AND WEST COAST METRO AREAS WITH SCATTERED ACTIVITY FORECAST
INTERIOR REGIONS.
TONIGHT INTO SATURDAY A COLD FRONT THAT IS CURRENTLY JUST NORTH OF
THE CAROLINAS IS FORECAST TO MOVE INTO NORTH FLORIDA ON SATURDAY
AND BECOME DIFFUSE THE REMAINDER OF THE WEEKEND. THE
AFOREMENTIONED CUT-OFF UPPER LEVEL LOW IS FORECAST TO QUICKLY LIFT
OFF TO THE NORTHEAST TODAY AND TONIGHT AND GET MERGED INTO A LARGE
AMPLITUDE UPPER LEVEL TROUGH FORECAST TO DIG INTO THE EASTERN SEA-
BOARD ON SATURDAY. FOR SATURDAY...WITH LINGERING MOISTURE ACROSS
THE REGION AND EASTERLY FLOW RETURNING MAINLY AFTERNOON ISOLATED
TO SCATTERED SHOWERS/THUNDERSTORMS ARE FORECAST WITH ISOLATED
ACTIVITY EXPECTED ACROSS THE EASTERN THIRD OF THE PENINSULA AND
SCATTERED ACROSS THE REMAINDER OF THE PENINSULA. BY SUNDAY THE
LARGE AMPLITUDE UPPER LEVEL TROUGH DIGS INTO THE SOUTHEAST U.S.
AND INTO THE REGION. THAT COUPLED WITH AN ADDITIONAL INFLUX OF
MOISTURE FROM THE ATLANTIC WATERS IS FORECAST TO RESULT IN
AFTERNOON SCATTERED SHOWERS AND THUNDERSTORMS. SIMILAR SYNOPTIC
CONDITIONS WILL PERSIST THROUGH THE EARLY PART OF THE WEEK. IN THE
LATER HALF OF THE WEEK ALTHOUGH MID TO UPPER LEVEL RIDGING BUILDS
INTO THE REGION...DEEP LAYERED MOISTURE IS FORECAST TO PREVAIL
ACROSS THE AREA WITH DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS
FORECAST WEDNESDAY THROUGH FRIDAY.
MARINE...
WINDS ACROSS THE REGIONAL WATERS TODAY WILL BE LIGHT AND COULD AT
TIMES BECOME LIGHT AND VARIABLE. BY SATURDAY EASTERLY FLOW WILL
RETURN IN THE 6 TO 10 KNOT RANGE AND THEN BY MONDAY THROUGH MID-
WEEK MODERATE EASTERLY FLOW IN THE 10 TO 15 KNOT RANGE IS
FORECAST. TODAY THROUGH THE WEEKEND SEAS ACROSS THE GULF AND
ATLANTIC WATERS ARE EXPECTED TO BE 2 FEET OR LESS AND MONDAY
THROUGH NEXT WEEK SEAS FROM 2 TO 3 FEET ARE POSSIBLE ACROSS THE
ATLANTIC WATERS AND THE OFF SHORE GULF WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 75 89 78 / 20 20 20 30
FORT LAUDERDALE 89 79 90 80 / 20 10 20 30
MIAMI 90 77 90 79 / 20 10 20 20
NAPLES 90 75 93 76 / 20 10 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...23/SK
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
213 AM EDT FRI SEP 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BE IN THE FORECAST AREA FRIDAY.
COOLER WEATHER WILL OCCUR BEHIND THE FRONT SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ISOLATED SHOWERS DEVELOPING...CSRA AND EAST MIDLANDS. HRRR GUIDANCE
SUGGESTS A FEW SHOWERS POSSIBLE OVERNIGHT. POPS REMAIN LOW HOWEVER
WITH WEAK FORCING AS FRONT APPROACHES. RAISED POPS FROM PREVIOUS
FORECAST DURING THE EARLY MORNING HOURS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS THE UPPER TROUGH MOVES ACROSS NEW ENGLAND AND THE MID-ATLANTIC
STATES A COLD FRONT WILL PUSH SOUTHEASTWARD THROUGH THE FORECAST
AREA FRIDAY AFTERNOON. AGAIN MOISTURE IS NOT IDEAL BUT SOME
POOLING OF MOISTURE AHEAD OF THE FRONT IS EXPECTED AND THERE
SHOULD BE ENOUGH INSTABILITY FROM DAYTIME HEATING ALONG WITH LOW-
LEVEL CONVERGENCE ALONG THE FRONTAL BOUNDARY TO WARRANT LOW CHANCE
POPS ALONG AND AHEAD OF THE FRONT. WITH LIMITED MOISTURE...WILL
CARRY A 20 PERCENT POP EVERYWHERE MAINLY FRIDAY IN THE AFTERNOON.
FRIDAY HIGHS ARE EXPECTED TO BE AROUND THE 90 DEGREE MARK. THE
CHANCE OF SHOWERS AND STORMS WILL DIMINISH FROM THE NORTHWEST AS
THE FRONT PUSHES THROUGH AND COOLER...DRIER AIR BUILDS INTO THE
AREA. WEAK COLD ADVECTION WILL ALLOW TEMPERATURES TO FALL INTO THE
LOWER TO MID 60S FRIDAY NIGHT. COOLER SATURDAY WITH DRY HIGH
PRESSURE. HIGHS SATURDAY FROM THE UPPER 70S NORTH TO LOWER 80S
SOUTH. LOWS SATURDAY NIGHT FROM THE MIDDLE 50S NORTH TO UPPER 50S
SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT SUNDAY AS SIGNIFICANT
MID LEVEL SHORT WAVE MOVES EAST AND SUPPRESSES WESTERN EXTENSION
OF BERMUDA RIDGE TO THE SOUTH TO NEAR THE GULF COAST REGION. BY
MONDAY AND TUESDAY...THE MAJOR UPPER TROUGH IS RE-ESTABLISH ALONG
THE EAST COAST. SOME MODEL DIFFERENCES MONDAY AND TUESDAY AS UPPER
TROUGH ALLOWS A WEAK COLD FRONT TO DROP TO THE SOUTH INTO THE
CAROLINAS. GFS BRINGS ENOUGH MOISTURE FOR ABOUT A 20 PERCENT CHANCE
OF PRECIPITATION WHILE THE ECMWF LOOKS DRIER. DECIDED TO GO WITH
CURRENT DRIER FORECAST WITH NO POPS. AT ANY RATE...MORE FALL-LIKE
SUNDAY WITH HIGHS ONLY IN THE LOWER 80S. WITH SOME UPPER HEIGHT
RISES MONDAY AND TUESDAY...THE MIDDLE 80S LOOKED BETTER. LOWS IN
THE UPPER 50S SUNDAY NIGHT ALSO INCREASE TO THE LOWER 60S MONDAY
NIGHT.
WEDNESDAY THROUGH THURSDAY...MORE MODEL DIFFERENCES LATE IN THE
PERIOD. GFS TRIES TO BUILD UPPER RIDGE TOWARD THE EAST WEDNESDAY
AND THURSDAY AND GIVES WARMER HIGH TEMPERATURES IN THE UPPER 80S.
ON THE OTHER HAND...ECMWF HAS UPPER RIDGE MORE SUPPRESSED AS A
STRONGER NORTHERN STREAM SHORT WAVE MOVES EASTWARD TOWARD THE
GREAT LAKES. THE WEAK COLD FRONT SHOULD STILL BE IN THE AREA
WEDNESDAY AND MAY PICK UP ENOUGH MOISTURE FOR A 20 PERCENT CHANCE
ON WEDNESDAY. THIS WEAK FRONT IS EXPECTED TO HAVE DISSIPATED BY
THURSDAY BUT MORE CLOUDS AND A BETTER CHANCE OF PRECIPITATION
SHOULD FAVOR THE SLIGHTLY COOLER ECMWF TEMPERATURES OVER GFS.
SO...DECIDED TO GO WITH HIGHS IN THE MIDDLE 80S FOR WEDNESDAY
AND THURSDAY. OTHERWISE...OVERNIGHT LOWS FROM THE LOWER 60S
IN THE NORTH TO MIDDLE 60S IN THE SOUTH FOR TUESDAY NIGHT AND
WEDNESDAY NIGHT.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS TO DOMINATE THE TAF PERIOD.
COLD FRONT CONTINUES TO MOVE INTO THE REGION WITH A FEW SHOWERS
PASSING THE AGS/DNL AREA. SHOWERS IN THE UPSTATE CONTINUE TO
DIMINISH CROSSING THE MOUNTAINS WITH LOW CONFIDENCE ANY ACTIVITY
WILL REACH THE TAF SITES. WITH THE FRONT MOVING INTO THE AREA THE
THREAT OF FOG REMAINS TOO LOW TO INCLUDE IN TAFS. THE FRONT WILL
CROSS THE AREA DURING THE MORNING AND OFFSHORE IN THE AFTERNOON
WITH DRIER AIR AND NORTHERLY WINDS MOVING IN BEHIND THE FRONT. AS
SUCH EXPECT VFR CONDITIONS THROUGH THE PERIOD.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED AT THIS TIME.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1213 AM EDT FRI SEP 13 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL BE IN THE FORECAST AREA FRIDAY. COOLER
WEATHER WILL OCCUR BEHIND THE FRONT SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ISOLATED SHOWERS DEVELOPING...CSRA AND EAST MIDLANDS. HRRR GUIDANCE
SUGGESTS A FEW SHOWERS POSSIBLE OVERNIGHT. POPS REMAIN LOW HOWEVER
WITH WEAK FORCING AS FRONT APPROACHES. RAISED POPS FROM PREVIOUS
FORECAST DURING THE EARLY MORNING HOURS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS THE UPPER TROUGH MOVES ACROSS NEW ENGLAND AND THE MID-ATLANTIC
STATES A COLD FRONT WILL PUSH SOUTHEASTWARD THROUGH THE FORECAST
AREA FRIDAY AFTERNOON. AGAIN MOISTURE IS NOT IDEAL BUT SOME
POOLING OF MOISTURE AHEAD OF THE FRONT IS EXPECTED AND THERE
SHOULD BE ENOUGH INSTABILITY FROM DAYTIME HEATING ALONG WITH LOW-
LEVEL CONVERGENCE ALONG THE FRONTAL BOUNDARY TO WARRANT LOW CHANCE
POPS ALONG AND AHEAD OF THE FRONT. WITH LIMITED MOISTURE...WILL
CARRY A 20 PERCENT POP EVERYWHERE MAINLY FRIDAY IN THE AFTERNOON.
FRIDAY HIGHS ARE EXPECTED TO BE AROUND THE 90 DEGREE MARK. THE
CHANCE OF SHOWERS AND STORMS WILL DIMINISH FROM THE NORTHWEST AS
THE FRONT PUSHES THROUGH AND COOLER...DRIER AIR BUILDS INTO THE
AREA. WEAK COLD ADVECTION WILL ALLOW TEMPERATURES TO FALL INTO THE
LOWER TO MID 60S FRIDAY NIGHT. COOLER SATURDAY WITH DRY HIGH
PRESSURE. HIGHS SATURDAY FROM THE UPPER 70S NORTH TO LOWER 80S
SOUTH. LOWS SATURDAY NIGHT FROM THE MIDDLE 50S NORTH TO UPPER 50S
SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT SUNDAY AS SIGNIFICANT
MID LEVEL SHORT WAVE MOVES EAST AND SUPPRESSES WESTERN EXTENSION
OF BERMUDA RIDGE TO THE SOUTH TO NEAR THE GULF COAST REGION. BY
MONDAY AND TUESDAY...THE MAJOR UPPER TROUGH IS RE-ESTABLISH ALONG
THE EAST COAST. SOME MODEL DIFFERENCES MONDAY AND TUESDAY AS UPPER
TROUGH ALLOWS A WEAK COLD FRONT TO DROP TO THE SOUTH INTO THE
CAROLINAS. GFS BRINGS ENOUGH MOISTURE FOR ABOUT A 20 PERCENT CHANCE
OF PRECIPITATION WHILE THE ECMWF LOOKS DRIER. DECIDED TO GO WITH
CURRENT DRIER FORECAST WITH NO POPS. AT ANY RATE...MORE FALL-LIKE
SUNDAY WITH HIGHS ONLY IN THE LOWER 80S. WITH SOME UPPER HEIGHT
RISES MONDAY AND TUESDAY...THE MIDDLE 80S LOOKED BETTER. LOWS IN
THE UPPER 50S SUNDAY NIGHT ALSO INCREASE TO THE LOWER 60S MONDAY
NIGHT.
WEDNESDAY THROUGH THURSDAY...MORE MODEL DIFFERENCES LATE IN THE
PERIOD. GFS TRIES TO BUILD UPPER RIDGE TOWARD THE EAST WEDNESDAY
AND THURSDAY AND GIVES WARMER HIGH TEMPERATURES IN THE UPPER 80S.
ON THE OTHER HAND...ECMWF HAS UPPER RIDGE MORE SUPPRESSED AS A
STRONGER NORTHERN STREAM SHORT WAVE MOVES EASTWARD TOWARD THE
GREAT LAKES. THE WEAK COLD FRONT SHOULD STILL BE IN THE AREA
WEDNESDAY AND MAY PICK UP ENOUGH MOISTURE FOR A 20 PERCENT CHANCE
ON WEDNESDAY. THIS WEAK FRONT IS EXPECTED TO HAVE DISSIPATED BY
THURSDAY BUT MORE CLOUDS AND A BETTER CHANCE OF PRECIPITATION
SHOULD FAVOR THE SLIGHTLY COOLER ECMWF TEMPERATURES OVER GFS.
SO...DECIDED TO GO WITH HIGHS IN THE MIDDLE 80S FOR WEDNESDAY
AND THURSDAY. OTHERWISE...OVERNIGHT LOWS FROM THE LOWER 60S
IN THE NORTH TO MIDDLE 60S IN THE SOUTH FOR TUESDAY NIGHT AND
WEDNESDAY NIGHT.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
REGIONAL RADARS INDICATE ADDITIONAL THUNDERSTORM ACTIVITY ALONG
THE CENTRAL APPALACHIANS...BUT THIS ACTIVITY IS NOT EXPECTED TO
HOLD TOGETHER INTO OUR CWA TONIGHT DUE TO LIMITED MOISTURE AND
GENERAL NORTHWEST FLOW PATTERN. SO EXPECTING VFR CONDITIONS DURING
THE TAF PERIOD. SOME OF THE MOS GUIDANCE SHOWS THE POSSIBILITY OF
UPPER END MVFR FOG DURING THE EARLY MORNING HOURS...BUT CONFIDENCE
IN FORMATION IS NOT HIGH DUE TO DEVELOPMENT OF A LOW-LEVEL JET AND
LOW-LEVEL MIXING OVERNIGHT. SO AS STATED ABOVE...VFR FORECAST. THE
MAIN FRONT WILL BE PASSING THROUGH THE FORECAST AREA DURING THE
MORNING ON FRIDAY...BUT IT SHOULD MOVE THROUGH TAF SITES
DRY...WITH ONLY A WIND SHIFT TO THE NORTHWEST TO SHOW ITS PASSAGE.
SCATTERED CU EXPECTED THROUGH THE DAY...GENERALLY AROUND 4.5KFT.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED AT
THIS TIME.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
803 PM MDT SAT SEP 14 2013
.UPDATE...
ISSUED AT 757 PM MDT SAT SEP 14 2013
JUST COMPLETED AN UPDATE. MAIN CHANGE WAS READJUST THE POP FIELD.
MAJORITY OF THE MODELS AND FORECAST WAS EMPHASIZING THE SOUTHEAST
PORTION OF THE AREA. PER MESOANALYSIS AND MODEL DATA ALONG WITH
REALITY MAIN AREA OF THUNDERSTORMS LOOKS TO INITIALLY BE THE
NORTHWEST CORNER AND THEN SPREADING EAST ACROSS THE REMAINDER OF
THE NORTHERN TIER OF COUNTIES. THIS IS WHERE PREFRONTAL SURFACE
TROUGH AND THEN COLD FRONT WILL COINCIDE WITH THE DEEPEST MOISTURE
AND MID/UPPER LEVEL LIFT.
SOUTHEAST PORTION OF THE AREA LOOKS CAPPED. HOWEVER THAT SHOULD
CHANGE BY LATER TONIGHT. THE HRRR FOLLOWED BY THE GFS WAS CATCHING
THE PRECIPITATION FIELD THE BEST. ALSO ADJUSTED THE SKY COVER AND
WIND PER LATEST TRENDS AND MESOSCALE MODEL DATA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM MDT SAT SEP 14 2013
A SURFACE LEE TROUGH IS DEEPENING AND MOVING EASTWARD ACROSS THE
FORECAST AREA THIS AFTERNOON IN RESPONSE TO A COUPLE OF WEAK SHORT
WAVES ROTATING AROUND THE MAIN UPPER LOW THAT IS VERY SLOW TO LIFT
OUT OF THE INTERMOUNTAIN REGION. THIS SURFACE TROUGH IS IN ADVANCE
OF A COLD FRONT THAT PUSHES SOUTHWARD INTO THE REGION ON SUNDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG AND EAST OF THE SURFACE TROUGH THIS LATE THIS AFTERNOON AND
EVENING ALONG WITH WITH A FEW STORMS DEVELOPING OVER THE FRONT RANGE
MOVING EAST OVER THE PLAINS THAT ARE EXPECTED TO DIMINISH THIS
EVENING. SCATTERED STORMS WILL DEVELOP AGAIN SUNDAY AFTERNOON
MAINLY IN THE VICINITY OF THE FRONT AS IT PUSHES SOUTH ACROSS THE
FORECAST AREA. LIGHT TO MODERATE RAINFALL IS EXPECTED WITH THESE
STORMS...WHICH COULD PRODUCE LOCALIZED AREAS OF FLOWING WATER IN
STREAM BEDS THAT ARE EITHER NORMALLY DRY OR STILL HAVE SOME WATER IN
THEM REMAINING FROM THE RECENT HEAVY RAINFALLS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 250 PM MDT SAT SEP 14 2013
SUNDAY NIGHT THROUGH MONDAY NIGHT NUMEROUS UPPER LEVEL SHORT WAVE
TROUGHS WILL MOVE OVER THE AREA. THE ENVIRONMENT WILL HAVE SOME
CONVECTIVE INSTABILITY AND THE PLUME OF SUBTROPICAL MOISTURE WILL
PERSIST OVER THE AREA UNTIL MONDAY NIGHT. THE STRONGEST UPPER LEVEL
TROUGH WITH THE BEST INSTABILITY WILL MOVE OVER THE AREA SUNDAY
NIGHT. DIFFICULT TO BE TOO EXCITED ABOUT PRECIP. CHANCES GIVEN THE
LIFT ASSOCIATED WITH THE TROUGH IS ON THE WEAKER SIDE. HOWEVER THE
LAST FEW DAYS HAVE HAD GOOD STORM DEVELOPMENT WITH RATHER BENIGN
LOOKING SHORT WAVE TROUGHS. MONDAY THE CONVECTIVE INSTABILITY
DIMINISHES SOME AND THE SHORT WAVE TROUGHS LOOK WEAKER...SO WILL
HAVE LOWER PRECIP. CHANCES AS A RESULT...WITH CHANCES ENDING FROM
WEST TO EAST AS DRIER AIR MOVES IN MONDAY EVENING. MEANWHILE THE COLD
FRONT FROM SUNDAY WILL MOVE IN FROM THE WEST AS A WARM FRONT AND
STALL OVER THE AREA MONDAY NIGHT. SLOW STORM MOTIONS WILL LEAD TO A
THREAT FOR HEAVY RAINFALL.
TUESDAY THROUGH SATURDAY THE NEXT BEST CHANCE FOR RAINFALL WILL BE
WEDNESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA WHILE AN
UPPER LEVEL LOW MOVES ACROSS THE NORTHERN PLAINS. WITH THE TRI-
STATE AREA BEING ON THE FAR SOUTHERN SIDE OF THE LOW...PRECIP.
CHANCES WILL BE CONFINED TO THE FRONTAL PASSAGE. BEHIND THE UPPER
LEVEL LOW A RIDGE WILL BUILD OVER THE AREA FOR THE WEEKEND.
TEMPERATURES FOR THE PERIOD WILL START OUT ABOVE NORMAL AS A WARM
FRONT MOVES THROUGH THE AREA FROM THE WEST TUESDAY. NEAR NORMAL
TEMPERATURES RETURN BEHIND THE COLD FRONT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 545 PM MDT SAT SEP 14 2013
UNTIL LATE IN THE PERIOD...VFR CONDITIONS ARE EXPECTED AT BOTH SITES.
AT THIS TIME...A COUPLE OF SURFACE BOUNDARIES AND A SHORTWAVE TROUGH ARE
CAUSING THUNDERSTORMS TO DEVELOP TO THE WEST OF BOTH SITES.
EXPECTED STORM MOTION WOULD FAVOR STORMS TO CONTINUE TO STAY TO
THE WEST OF BOTH SITES BUT CANNOT TOTALLY RULE OUT STORM GETTING
CLOSE. SO PLAN ON ONLY KEEPING VCTS AT BOTH SITES THROUGH THE
EVENING HOURS. HOWEVER...IT IS POSSIBLE FOR THUNDERSTORMS TO
CONTINUE THROUGH MOST OF THE NIGHT DUE TO A SURFACE TROUGH AND
THEN A COLD FRONT THAT COMES THROUGH LATER TONIGHT.
IN THE 10Z TO 13Z TIME FRAME...EXPECT A COLD FRONT TO COME THROUGH.
MODELS INDICATE THAT STRATUS IN THE MVFR CATEGORY WILL DEVELOP
RATHER QUICKLY BEHIND THE FRONT. THIS STRATUS LOOKS TO REMAIN MOST
IF NOT THE ENTIRE DAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JTL
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
625 PM CDT Sat Sep 14 2013
...Updated aviation discussion...
.SYNOPSIS...
ISSUED AT 911 AM CDT SAT SEP 14 2013
The 14.12Z 250 hPa raob map showed fairly light flow across much of
the CONUS with magnitudes 50 kt or less. The exception to this was across
the northeast where a meridional flow was observed with peak magnitudes
in the 100-120 kt range. @ 500 hPa, the flow was fairly messy with an
anticyclone over BC, two pressure perturbations across Utah and Wyoming,
an anticyclone over Texas, and an elongated trof across the Northeast.
@ 700 hPa and 850 hPa, low level moisture was noted at KDDC. The pwat
for KDDC was 1.46", or around the +2SD statistical mark. @ the sfc,
a stationary front was located across the lee of the Rockies. This boundary
turned into a cold front across south Texas. The tropics was busy with
Tropical Storm Humberto @ 25.0N 34.0W @ 14.09Z, Tropical Storm Ingrid
@ 19.8N 95.0W @ 14.09Z, and finally Tropical Storm Manuel @ 15.3N 102.4W
@ 14.09Z.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 1234 PM CDT SAT SEP 14 2013
Tonight:
Additional shower and thunderstorm activity will be possible this evening.
The nested 4 km NAM and WRF-NMM are in fair agreement with convective
activity tonight. Used a model blend for precipitation probability adjustments.
Severe weather is not expected due to moist adiabatic lapse rates and
low forecast CAPE values as well as weak bulk shear. Otherwise, minimums
will be in the upper 50sF west to mid 60sF east.
Tomorrow:
A front will move across the region tomorrow. This boundary will have
two sensible weather impacts. The first is that there will be quite
the maximum temperature gradient across the region with mid 70sF across
the northwest zones to around 90F across south central Kansas. The second
will be additional convection. Instability and bulk shear will be stronger
than compared to today for tomorrow, however, the undercutting nature
of the cold front should limit severe potential. Used a blend of the
two cores of the WRF and the operational NAM for precipitation probability
percentage points adjustments.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 215 PM CDT SAT SEP 14 2013
Medium range models indicate an upper level trough of low pressure
swinging southeast across the Great Lakes Region Sunday night.
Meanwhile, a cold front attendant to the upper level trough is
projected to push south into western Kansas Sunday evening providing
the focus for potential shower and thunderstorm development across
the area into Monday. Ample low level moisture will be available
with H85 dewpoints up around 12C to 15C across central and southwest
Kansas. Although the flow aloft is expected to remain fairly weak,
enough low level forcing combined with modest instability (CAPE
values in excess of 500 to 1000 J/KG) will be enough to support
some shower and isolated thunderstorm development across central
and southwest Kansas Sunday night into Monday. Widespread severe
weather is unlikely.
Another round of showers and thunderstorms will be possible again
Monday night into Tuesday as a secondary upper level shortwave
ejects east out of the Rockies into the Western High Plains during
this time frame. Although the flow aloft will remain fairly weak, a
more favorable vertical shear profile will set up as a southeasterly
upslope flow quickly returns to western Kansas. NAM/GFS model
soundings show marginal instability initially Monday evening with
instability levels gradually increasing through the overnight hours
into Tuesday. As a result, showers along with a few potential
isolated thunderstorms will be possible across central and southwest
Kansas, with the best chance for precip closer to the Oklahoma border
where a near stationary frontal boundary is expected to be located
late Monday/early Tuesday. Chances for precip will continue each day
through the remainder of the week as yet another upper level trough
is progged to push east out of the Pacific Northwest into the
Northern High Plains, pushing another cold front into western Kansas
by Thursday.
Much cooler temperatures are expected going into Monday as the
aforementioned cold front pushes south across western Kansas into
Oklahoma giving way to a northeast to easterly low level flow across
the area. Medium range models show cooler air filtering southwest
into western Kansas with H85 temperatures dropping into the mid to
upper teens(C). Along with increased cloud cover and potential areas
of precip around, highs are expected to climb only up into the
70s(F) across much of the area Monday afternoon with near 80F
possible in south central Kansas. A gradual warming trend will
occur through at least Wednesday as lee side troughing develops
across eastern Colorado helping return a low level southerly flow
to western Kansas. Widespread 80s(F) are likely Tuesday with near
90F possible in some locations Wednesday. The seasonable
temperatures are expected to continue into the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 625 PM CDT SAT SEP 14 2013
Isolated thunderstorm activity across Seward and Meade counties
picked up well by HRRR and should dissipate over next couple of
hours. With that, no mention of any thunderstorms was made in
TAFs. Will continue to watch and update to include VCTS if
necessary.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 64 84 60 74 / 40 40 50 40
GCK 63 80 57 72 / 40 40 40 30
EHA 61 80 57 74 / 30 30 40 40
LBL 63 86 59 76 / 40 30 40 40
HYS 63 79 58 72 / 30 40 40 30
P28 66 89 64 80 / 30 30 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Sugden
LONG TERM...JJohnson
AVIATION...Wolfe
AREA FORECAST DISCUSSION
NWS DULUTH MN
1241 AM CDT FRI SEP 13 2013
.UPDATE...
ISSUED AT 932 PM CDT THU SEP 12 2013
HAVE ADDED PATCHY FROST TO ALL REMAINING ZONES AND GRIDS FOR THE
REST OF THE NIGHT. THE FREEZE WARNING AREA STILL LOOKS GOOD...AS
WELL AS THE FROST ADVISORY AREA. CONSIDERED EXPANDING THE FROST
ADVISORY A BIT BUT DECIDED TO HOLD OFF AND ADD PATCHY FROST
MENTION TO THE REMAINDER OF THE NORTHLAND. CLOUDS HAVE CLEARED
NICELY ACROSS THE REGION...WITH CLEAR TO MOSTLY CLEAR SKIES FOR
THE REST OF THE NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 322 PM CDT THU SEP 12 2013
AT 315PM/2015Z...SURFACE HIGH PRESSURE WAS CENTERED OVER THE
NORTHERN PLAINS...SOMEWHERE NEAR THE NORTH DAKOTA AND MANITOBA
BORDER. MUCH OF THE UPPER MIDWEST...INCLUDING THE NORTHLAND...HAD
COOL NORTHERLY FLOW WHICH WAS RESULTING IN PARTLY TO MOSTLY CLOUDY
SKIES ACROSS THE REGION. TEMPERATURES ACROSS THE NORTHLAND RANGED
FROM THE LOW 50S OVER THE TIP OF THE ARROWHEAD TO THE LOW TO MID
60S ACROSS MUCH OF THE REST OF THE NORTHLAND. THE BRAINERD LAKES
REGION HAD MID 60S TO LOW 70S. DEW POINT TEMPERATURES RANGED FROM
THE UPPER 30S OVER THE TIP OF THE ARROWHEAD...TO THE LOW TO MID
40S ACROSS THE REST OF THE NORTHLAND.
TONIGHT...THE HIGH PRESSURE IN THE NORTHERN PLAINS WILL MOVE OVER
THE NORTHLAND. THIS SHOULD RESULT IN AN OVERALL TREND IN CLEARING
SKIES AND DIMINISHING WIND WHICH WILL BE A RECIPE FOR A COLD NIGHT
ACROSS THE NORTHLAND. I BELIEVE OVERALL THE MODEL GUIDANCE IS
UNDERESTIMATING THE DEGREE OF RADIATIONAL COOLING TONIGHT...SO I
LEANED AND FORECASTED SLIGHTLY BELOW THE COLDEST GUIDANCE. FAR
NORTHERN MINNESOTA STILL LOOKS LIKE IT WILL BE THE COLDEST PART OF
THE FORECAST AREA AND WILL VERY LIKELY PLUMMET TO NEAR AND SUB
FREEZING TEMPERATURES. I MAINTAINED A FREEZE WARNING FOR THE IRON
RANGE AND INTERIOR ARROWHEAD...AS WELL AS THE FROST ADVISORY FOR
KOOCHICHING COUNTY...BUT ADDED NORTHERN ITASCA COUNTY TO THE FROST
ADVISORY. I STILL HAVE A LITTLE CONCERN ABOUT LINGERING CLOUD COVER
TONIGHT AND HOW IT MAY PREVENT TEMPERATURES FROM GETTING AS COLD
AS FORECAST. HOWEVER...LATEST HRRR MODEL RUNS ARE SHOWING PRETTY
GOOD CLEARING TONIGHT. THERE MIGHT BE A LITTLE LINGERING CLOUD
COVER HERE AND THERE...SUCH AS THE TIP OF THE ARROWHEAD...BUT I
THINK IT WILL HAVE LITTLE IMPACT TO THE FORECAST. I ADDED PATCHY
FROST TO OTHER PARTS OF THE NORTHLAND...SUCH AS PARTS OF THE SW
AND SE FORECAST AREA...BUT HELD OFF ON EXPANDING FROST ADVISORIES
TO THOSE AREAS SINCE THE TEMPERATURES LOOK TO BE BORDERLINE FOR
FROST. ALSO...THERE MAY BE LINGERING CLOUD COVER OVER PARTS OF NW
WISCONSIN DUE TO THE NORTH WINDS OFF LAKE SUPERIOR. THE EVENING
SHIFT WILL NEED TO MONITOR TRENDS AND RECONSIDER ADDING OTHER
PARTS OF THE FORECAST AREA TO THE FROST ADVISORY.
FRIDAY...THE HIGH PRESSURE WILL BEGIN TO SHIFT TOWARDS SOUTHERN
MINNESOTA AND IOWA. LIGHT SSW WINDS WILL DEVELOP ACROSS NE
MINNESOTA. SUNNY SKIES ARE EXPECTED WITH HIGHS IN THE MID TO UPPER
60S ACROSS MOST OF THE NORTHLAND...SAVE THE TIP OF THE ARROWHEAD
WHICH WILL SEE UPPER 50S TO LOW 60S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 322 PM CDT THU SEP 12 2013
FRIDAY NIGHT THE SURFACE RIDGE AND COLD TEMPERATURES SLIDE OFF TO
THE SOUTHEAST AND ALLOW SOUTHWEST RETURN FLOW TO BEGIN OVER THE
AREA. THIS CONTINUES...WITH GRADUALLY WARMING TEMPERATURES INTO
SATURDAY. ON SATURDAY A STRONG SHORTWAVE AND COLD FRONT PUSHES
INTO THE AREA FROM THE NORTHWEST. AT THE SAME TIME...A CUT OFF
UPPER LOW THAT HAS BEEN SITTING OVER THE SOUTHWEST CONUS THE LAST
FEW DAYS FINALLY GETS CAUGHT UP IN THE NORTHERN STREAM...AND
EJECTS OUT OVER THE PLAINS. THE RESULTING SYSTEM PULLS SOME
MOISTURE UP INTO OUR AREA...WITH A WARM FRONT THAT GETS AS FAR
NORTH AS SOUTH DAKOTA AND SOUTHERN MN SATURDAY NIGHT. THIS SHOULD
PRODUCE SOME SHOWERS AND ISOLATED THUNDER ACROSS OUR SOUTH
BEGINNING LATE SATURDAY AFTERNOON AND NIGHT...WITH SCATTERED
SHOWERS AND THUNDERSTORMS ALONG THE COLD FRONT SATURDAY NIGHT AND
EARLY SUNDAY. TEMPERATURES REMAIN MILD SOUTH OF THE FRONT...BUT
SATURDAY NIGHT MINS WILL RANGE FROM THE LOW TO MID 50S SOUTH...TO
THE MID 40S NORTH OF THE COLD FRONT.
SUNDAY TO BE MUCH COLDER AND DRIER WITH A SURFACE RIDGE BUILDING
ACROSS THE AREA...AND UPPER LEVEL RIDGING BUILDING AS WELL. SUNDAY
HIGHS ONLY RANGING FROM AROUND 60 NORTH TO THE MID 60S SOUTH.
SUNDAY NIGHT MINS COULD ONCE AGAIN BE COLD ENOUGH FOR
FROST...WITH MINS IN THE 30S TO AROUND 40.
THE UPPER LEVEL RIDGE SHIFTS OFF TO THE EAST BY EARLY IN THE
WEEK...ALLOWING A MORE SOUTHWEST FLOW SYSTEM TO ENTER THE AREA
MONDAY AND TUESDAY. A WAVE OF WARM AIR ADVECTION AND ISENTROPIC
LIFT MOVES INTO THE AREA BEGINNING MONDAY NIGHT...BRINGING A
CHANCE OF PRECIPITATION FOR MONDAY NIGHT THROUGH TUESDAY AND EVEN
EARLY WEDNESDAY. IT IS HARD TO SPECIFY ANY DRY PERIODS WITH THE
WARM MOIST AIR ADVECTION GOING ON ALOFT AND A WARM FRONT IN THE
VICINITY...THOUGH I AM SURE THERE WILL BE SOME. TEMPERATURES WILL
GRADUALLY WARM THROUGH WEDNESDAY. BY THURSDAY...THE SURFACE LOW
FINALLY BEGINS TO TAKE SHAPE IN THE PLAINS AND ADVANCES ACROSS
MINNESOTA DURING THE DAY. TRACK AND TIMING ARE STILL UNCERTAIN
WITH SOME SIGNIFICANT DIFFERENCES IN THE MODELS...BUT
PRECIPITATION CHANCES INCREASE AGAIN FOR THURSDAY WITH THE LOW IN
THE STATE AND PLENTY OF HEAT AND MOISTURE IN THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1240 AM CDT FRI SEP 13 2013
HIGH PRESSURE WILL BRING VFR CONDITIONS TO THE NORTHLAND THROUGHOUT
THE TAF PERIOD. THE EXCEPTIONS WILL BE SOME PATCHY FOG
OVERNIGHT...WHICH COULD RESULT IN LOCAL IFR/MVFR.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 48 71 54 63 / 0 20 30 10
INL 49 74 44 61 / 0 30 20 10
BRD 49 71 54 66 / 0 30 40 10
HYR 43 71 51 64 / 0 10 30 10
ASX 47 72 52 61 / 0 10 40 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR MNZ011-012-019.
FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ010-018.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...DAP
SHORT TERM...GROCHOCINSKI
LONG TERM...LE
AVIATION...DAP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1040 AM CDT FRI SEP 13 2013
.UPDATE...A BAND OF VERY ISOLATED PRE-FRONTAL SHOWERS OVER THE
NORTHERN HALF OF THE CWA DISSIPATED BEFORE REACHING JACKSON AND
MERIDIAN EARLIER THIS MORNING. THE COLD FRONT IS NOW KNOCKING ON THE
NORTHERN BORDER OF CWA WITH DEWPOINTS ALREADY FALLING INTO THE LOWER
60S AT TUPELO...OXFORD AND CLARKSDALE. WINDS HAVE SHIFTED TO N/NELY
ACROSS MUCH OF THE AREA AS THE PRESSURE TROUGH HAS ALREADY PUSHED
SOUTH TO THE I-20 CORRIDOR. AS INSTABILITY INCREASES THROUGH THE
DAY...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL REDEVELOP
SOUTH OF THE FRONT. THE LATEST HRRR SHOWS THIS REDEVELOPMENT
OCCURRING IN THE 18Z/19Z TIME FRAME MAINLY SOUTH OF A LINE FROM THE
AR/LA BORDER TO CARTHAGE TO DE KALB AND PUSHING SOUTH THROUGH THE
AFTERNOON AS THE FRONT CONTINUES TO MAKE PROGRESS ACROSS THE AREA.
ACTIVITY WILL THEN DECREASE AROUND 00Z/01Z DUE TO BOTH THE MOVEMENT
OF THE FRONT AND THE DECREASE OF INSTABILITY. THE CURRENT FORECAST
HAS A PRETTY GOOD HANDLE ON THE SITUATION. SOME MINOR ADJUSTMENTS
WILL BE MADE TO TEMP/DEWPOINT/ WIND/SKY GRIDS TO ADJUST TO THE
LATEST TRENDS AND FRONTAL TIMING. WILL ALSO BACK OFF ON POPS ALONG
THE 82 CORRIDOR AS IT BECOMES LESS AND LESS LIKELY THAT
REDEVELOPMENT OCCURS BEFORE THE FRONT MOVES THROUGH THAT AREA. /DL/
&&
.AVIATION...MAINLY VFR CONDS EXPECTED TO PREVAIL THROUGH THE DAY BUT
ISO/SCT SHRA EXPECTED TO DEVELOP ACROSS MAINLY SITES ALONG AND SOUTH
OF THE I-20 CORRIDOR EARLY AFTERNOON THROUGH EARLY EVENING AS A COLD
FRONT MOVES THROUGH THE REGION. WINDS WILL BE LIGHT AND NORTHERLY
AHEAD OF THE COLD FRONT AND THEN PICK UP TO 10-12KT FROM THE SAME
DIRECTION AS THE FRONT PASSES THIS AFTN FROM NORTH TO SOUTH. WINDS
WILL STAY UP AROUND 5 KTS THROUGH THE OVRNGT SAT MRNG. ANY CLOUD
CEILINGS SHOULD BE GREATER THAN 4 KFT ASIDE FROM A FEW HEAVIER
SHOWERS WHERE VERY BRIEF MVFR FLIGHT CATS COULD BE ENCOUNTERED
ACROSS JAN/HKS/NMM/MEI/PIB/HBG. /BB/
&&
.DISCUSSION... /ISSUED AT 1015 AM CDT FRI SEP 13 2013/
TODAY THROUGH SUNDAY MORNING
A WEAK COOL FRONT PASSAGE TODAY WILL AID IN ISOLATED TO SCATTERED
SHOWER DEVELOPMENT THIS MORNING THROUGH TONIGHT. A MUCH DRIER,
COOLER, AND QUITE COMFORTABLE AIRMASS WILL SETTLE IN FOR THE
WEEKEND.
THE AFOREMENTIONED COOL FRONT IS ANALYZED ALONG A NASHVILLE, TN TO
DYER, TN TO NORTH OF A LITTLE ROCK, AR LINE AT 08Z THIS MORNING.
THIS FRONT IS BEING DRIVEN BY A DEEPENING L/WV TROUGH ACROSS THE
EASTERN SEABOARD AND A STRENGTHENING SFC HIGH ACROSS THE UPPER
MIDWEST. AHEAD OF THIS FRONT HOWEVER, IS A PREFRONTAL TROUGH AND
ASSOCIATED H5 PVA RIBBON PER RAP ANALYSIS. THE TRAILING PREFRONTAL
TROUGH AXIS EXTENSION FROM THE NE CONUS HAS ALLOWED TO KICK OFF A
FEW SHOWERS EARLY THIS MORNING ACROSS FAR N/NE MS. THIS VERY
ISOLATED AND TRANSIENT ACTIVITY WILL FESTER THROUGH THE MORNING AND
WILL MOVE SOUTH IN CONJUNCTION WITH THE H5 PVA RIBBON. BY MID TO
LATE MRNG, THE FRONT SHOULD BE ON HWY-82 CORRIDOR DOORSTEP NORTH OF
THIS H5 RIBBON, AND THUS WILL MAINLY RELY ON INSTABILITY FACTORS FOR
PARCEL BUOYANCY VS. ANY DYNAMIC LIFT MECHANISM. ISOLATED SHOWERS
SHOULD GET GOING BETWEEN HWY-82 AND I-20 LATE MRNG/EARLY AFTN WITH
BETTER COVERAGE EXPECTED NEAR AND SOUTH OF I-20 BY MID AFTN AS SFC
BASED INSTABILITY BUILDS UPWARDS TO 1200 J/KG. SOME THUNDERSTORMS
MAY DEVELOP BUT WITH MEAGER INSTABILITY, WEAK LOW-LVL CONVERGENCE
AND POOR LAPSE RATES, NOT EXPECTING ANY STRONG THUNDERSTORMS NOR
MODEST LIGHTNING PRODUCERS. WENT WELL ABOVE MAV POPS AGAIN TOWARDS
MET NUMBERS IN THE 20-30% RANGE ACROSS THE REGION TODAY BUT BROKE UP
DAY TO INDICATE SHOWER PROBS DECREASING NORTH TO SOUTH THROUGH TIME.
SKIES WILL CLEAR THROUGH THE OVERNIGHT WITH THE FRONT PUSHING
THROUGH THE REGION TO THE SOUTH SATURDAY MRNG. SFC DEWPOINTS IN THE
LOW 50S NORTH TO NEAR 60 SOUTH WILL DROP HUMIDITY LEVELS AND MAKE IT
FEEL QUITE COMFORTABLE TO BE OUTSIDE THROUGH THE DAY. HIGHS SATURDAY
WILL TOP OUT IN THE LOW 80S NORTH TO UPPER 80S SOUTH, SOME 10-13F
DEGREES COOLER FROM THIS PAST WEEK. LOWS SATURDAY AND SUNDAY WILL
RANGE FROM THE MID 50S NORTH TO THE MID 60S SOUTH. /ALLEN/
SUNDAY THROUGH NEXT FRIDAY
NUMERICAL MODELS CONTINUE TO BE IN SOLID AGREEMENT ON
THE MED RANGE/LONG TERM. THE GENERAL PATTERN WILL CONTINUE TO BE ONE
OF RIDGING ALOFT...ALBEIT WEAKER THAN WHAT WE HAVE BEEN SEEING...AND
STEADY MOISTENING AS WE GO THROUGH THE WORK WEEK.
THE COOL FRONT WILL WASH OUT ON SUNDAY AND ALLOW FOR A DECENT WARM
UP ALONG WITH ALLOWING BETTER LOW LEVEL MOISTURE TO RETURN ACROSS
THE S HALF OF THE CWA. WHILE NOT MUCH SHOWER ACTIVITY IS
EXPECTED...CAN`T RULE OUT AN ISOLATED SHOWER ACROSS THE HWY 84
CORRIDOR BY AFTERNOON. THE PATTERN WILL STEADILY TRANSITION THROUGH
MIDWEEK AND BECOME ONE WITH A MORE DEEP SE FLOW. THIS WILL RESULT IN
ALLOWING MORE DEEP TROPICAL MOISTURE INTO THE REGION ALONG WITH SOME
WEAKENING OF THE SUBTROPICAL RIDGE. THE RESULT WILL BE BETTER PRECIP
CHANCES FOR MID/LATE WEEK. THIS MAY BE THE BEGINNING OF A WETTER
PATTERN TO END THE MONTH. WE WILL SEE IF THE MODELS CONTINUE TO SHOW
THIS OVER THE NEXT FEW RUNS.
AS FOR TEMPS...GFS GUIDANCE SEEMS TO HAVE A SOLID HANDLE ON EXPECTED
CONDITIONS. MODERATION WILL BE THE WORD FOR SUN-MON AS THE AREA
WARMS BACK INTO THE 90-95 DEGREE RANGE AGAIN. BY MID WEEK...DEEPER
MOISTURE...MORE CLOUDS AND INCREASED RAIN POTENTIAL WILL TAPER TEMPS
BACK TOWARD NORMAL. /CME/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DL/BB/ALLEN/CME
AREA FORECAST DISCUSSION
NWS JACKSON MS
345 AM CDT FRI SEP 13 2013
.DISCUSSION...
TODAY THROUGH SUNDAY MORNING
A WEAK COOL FRONT PASSAGE TODAY WILL AID IN ISOLATED TO SCATTERED
SHOWER DEVELOPMENT THIS MORNING THROUGH TONIGHT. A MUCH DRIER,
COOLER, AND QUITE COMFORTABLE AIRMASS WILL SETTLE IN FOR THE
WEEKEND.
THE AFOREMENTIONED COOL FRONT IS ANALYZED ALONG A NASHVILLE, TN TO
DYER, TN TO NORTH OF A LITTLE ROCK, AR LINE AT 08Z THIS MORNING.
THIS FRONT IS BEING DRIVEN BY A DEEPENING L/WV TROUGH ACROSS THE
EASTERN SEABOARD AND A STRENGTHENING SFC HIGH ACROSS THE UPPER
MIDWEST. AHEAD OF THIS FRONT HOWEVER, IS A PREFRONTAL TROUGH AND
ASSOCIATED H5 PVA RIBBON PER RAP ANALYSIS. THE TRAILING PREFRONTAL
TROUGH AXIS EXTENSION FROM THE NE CONUS HAS ALLOWED TO KICK OFF A
FEW SHOWERS EARLY THIS MORNING ACROSS FAR N/NE MS. THIS VERY
ISOLATED AND TRANSIENT ACTIVITY WILL FESTER THROUGH THE MORNING AND
WILL MOVE SOUTH IN CONJUNCTION WITH THE H5 PVA RIBBON. BY MID TO
LATE MRNG, THE FRONT SHOULD BE ON HWY-82 CORRIDOR DOORSTEP NORTH OF
THIS H5 RIBBON, AND THUS WILL MAINLY RELY ON INSTABILITY FACTORS FOR
PARCEL BUOYANCY VS. ANY DYNAMIC LIFT MECHANISM. ISOLATED SHOWERS
SHOULD GET GOING BETWEEN HWY-82 AND I-20 LATE MRNG/EARLY AFTN WITH
BETTER COVERAGE EXPECTED NEAR AND SOUTH OF I-20 BY MID AFTN AS SFC
BASED INSTABILITY BUILDS UPWARDS TO 1200 J/KG. SOME THUNDERSTORMS
MAY DEVELOP BUT WITH MEAGER INSTABILITY, WEAK LOW-LVL CONVERGENCE
AND POOR LAPSE RATES, NOT EXPECTING ANY STRONG THUNDERSTORMS NOR
MODEST LIGHTNING PRODUCERS. WENT WELL ABOVE MAV POPS AGAIN TOWARDS
MET NUMBERS IN THE 20-30% RANGE ACROSS THE REGION TODAY BUT BROKE UP
DAY TO INDICATE SHOWER PROBS DECREASING NORTH TO SOUTH THROUGH TIME.
SKIES WILL CLEAR THROUGH THE OVERNIGHT WITH THE FRONT PUSHING
THROUGH THE REGION TO THE SOUTH SATURDAY MRNG. SFC DEWPOINTS IN THE
LOW 50S NORTH TO NEAR 60 SOUTH WILL DROP HUMIDITY LEVELS AND MAKE IT
FEEL QUITE COMFORTABLE TO BE OUTSIDE THROUGH THE DAY. HIGHS SATURDAY
WILL TOP OUT IN THE LOW 80S NORTH TO UPPER 80S SOUTH, SOME 10-13F
DEGREES COOLER FROM THIS PAST WEEK. LOWS SATURDAY AND SUNDAY WILL
RANGE FROM THE MID 50S NORTH TO THE MID 60S SOUTH. /ALLEN/
SUNDAY THROUGH NEXT FRIDAY
NUMERICAL MODELS CONTINUE TO BE IN SOLID AGREEMENT ON
THE MED RANGE/LONG TERM. THE GENERAL PATTERN WILL CONTINUE TO BE ONE
OF RIDGING ALOFT...ALBEIT WEAKER THAN WHAT WE HAVE BEEN SEEING...AND
STEADY MOISTENING AS WE GO THROUGH THE WORK WEEK.
THE COOL FRONT WILL WASH OUT ON SUNDAY AND ALLOW FOR A DECENT WARM
UP ALONG WITH ALLOWING BETTER LOW LEVEL MOISTURE TO RETURN ACROSS
THE S HALF OF THE CWA. WHILE NOT MUCH SHOWER ACTIVITY IS
EXPECTED...CAN`T RULE OUT AN ISOLATED SHOWER ACROSS THE HWY 84
CORRIDOR BY AFTERNOON. THE PATTERN WILL STEADILY TRANSITION THROUGH
MIDWEEK AND BECOME ONE WITH A MORE DEEP SE FLOW. THIS WILL RESULT IN
ALLOWING MORE DEEP TROPICAL MOISTURE INTO THE REGION ALONG WITH SOME
WEAKENING OF THE SUBTROPICAL RIDGE. THE RESULT WILL BE BETTER PRECIP
CHANCES FOR MID/LATE WEEK. THIS MAY BE THE BEGINNING OF A WETTER
PATTERN TO END THE MONTH. WE WILL SEE IF THE MODELS CONTINUE TO SHOW
THIS OVER THE NEXT FEW RUNS.
AS FOR TEMPS...GFS GUIDANCE SEEMS TO HAVE A SOLID HANDLE ON EXPECTED
CONDITIONS. MODERATION WILL BE THE WORD FOR SUN-MON AS THE AREA
WARMS BACK INTO THE 90-95 DEGREE RANGE AGAIN. BY MID WEEK...DEEPER
MOISTURE...MORE CLOUDS AND INCREASED RAIN POTENTIAL WILL TAPER TEMPS
BACK TOWARD NORMAL. /CME/
&&
.AVIATION...VFR CONDS PREVAIL THIS MRNG BUT SOME PATCHY MVFR FOG
MAY STILL BE PSBL THROUGH 14Z FOR KMEI/KHBG. VFR CONDS EXPECTED TO
PREVAIL THROUGH THE DAY BUT ISO/SCT SHRA EXPECTED TO DEVELOP ACROSS
REGION AS WEAK COLD FRONT MOVES THROUGH THE REGION. WINDS WILL BE
LIGHT AND NORTHERLY AHEAD OF THE COLD FRONT AND THEN PICK UP TO
10-12KT FROM THE SAME DIRECTION AS THE FRONT PASSES THIS AFTN FROM
NORTH TO SOUTH. WINDS WILL STAY UP AROUND 5 KTS THROUGH THE OVRNGT
SAT MRNG. /ALLEN/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 93 62 85 60 / 27 6 0 0
MERIDIAN 93 59 86 57 / 27 7 0 0
VICKSBURG 93 61 87 59 / 27 7 0 0
HATTIESBURG 96 64 90 64 / 27 16 5 4
NATCHEZ 93 64 86 64 / 27 15 4 4
GREENVILLE 90 59 83 57 / 18 0 0 0
GREENWOOD 89 56 84 55 / 19 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
ALLEN/CME
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
924 PM CDT Sat Sep 14 2013
.UPDATE:
Issued at 921 PM CDT Sat Sep 14 2013
Not any major changes to previous forecast for tonight. Have
updated hourly T grids to capture faster drop in temps than
previously forecast. However...did not drop mins as IR satellite
depicts increasing mid/high level cloudiness. Only other change of
note was to delay rain chances a few hours more in line with
latest HRRR guidance.
Gosselin
&&
.SHORT TERM: (Through Late Tonight)
Issued at 353 PM CDT Sat Sep 14 2013
Quiet weather continues in the short term as a sprawling high
pressure system over the Ohio Valley drifts east overnight. Light
and variable wind will become more southerly tonight as a result,
and increasing cloud cover from a trof of low pressure over the
Great Plains will keep temperatures from dipping to low tonight.
Guidance temperatures in the low to mid 50s look very reasonable.
The cold front approaching our area from the northwest is also
slower than expected, so have backed off pops for tonight as well.
Carney
.LONG TERM: (Sunday through Next Saturday)
Issued at 353 PM CDT Sat Sep 14 2013
Upper trough currently extending from the Hudson Bay southwestward
into northern Plains will move southeast into the southern Great
Lakes by tomorrow evening. Both the GFS and WRF based models show
that the attendant cold front will move south into the CWA reaching
close to a Pittsfield to Columbia line by 00Z, and south of the CWA
by 12Z Monday. Moisture convergence will increase along and just
ahead of the front with most of the large scale ascent coincident or
just behind the front. Will keep rain chances mainly north of I-70
during the day on Sunday and then spread them south during the
evening. Best chances will be on Sunday afternoon when best ascent
from upper trough will be lined up with best low level forcing and
instability.
Have kept slight or low chance of storms going Monday as front never
moves very far to the south. Low chances of storms still look
warranted Tuesday and Tuesday night as low level moisture convergence
will set up under shortwave trough passing through the area.
GFS/ECMWF/Canadian GEM each show that an upper trough will amplify
Wednesday into Friday as it moves from the Pacific Northwest into
Upper Midwest. The 00Z ECMWF does carve out a deeper upper low
than the more consistent GFS by late Friday. Moisture begins to
flow northward from the Gulf ahead of the trough by midweek, so will
leave in rain chances beginning Tuesday night and continue them into
Friday when a cold front moves through the area. 850mb temperatures
between 16-18C with clouds and rain chances support highs in the low
to mid 80`s ahead of the cold front.
Britt
&&
.AVIATION: (For the 00z TAFs through 00z Sunday Evening)
Issued at 518 PM CDT Sat Sep 14 2013
Just VFR mid-high level cloudiness tgt ahead of an upper level
trough moving sewd through the nrn Plains. Sely sfc winds will
continue tgt as the large sfc high centered over the Ohio Valley
region moves sewd. A cold front will drop sewd to the UIN area
Sunday aftn. There should be scattered showers and thunderstorms
along this front. Will include prob30 for tsra in the UIN taf
Sunday aftn. Should also see VFR low-mid level cloudiness in UIN
as well Sunday aftn. The sfc wind will veer around to a s-swly
direction ahead of the front on Sunday at the taf sites...
eventually to a n-nwly direction by late Sunday aftn in UIN after
fropa.
Specifics for KSTL: Increasing high level clouds tgt...then mid
level clouds moving in on Sunday...and VFR low-mid level clouds
Sunday evng as the cold front drops sewd into the STL area. May
include prob30 for shra/tsra Sunday evng in the STL TAF. A weak
sely sfc tgt will increase to 9-10 kts on Sunday and veer around
to a swly direction.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
250 PM MDT FRI SEP 13 2013
.SHORT TERM...VALID FOR SAT AND SUN...
SLOW MOVING UPPER LOW CONTINUES TO SPIN OVER THE NORTHERN GREAT
BASIN...WITH IMPRESSIVE SUBTROPICAL MOISTURE FETCH ALONG THE HIGH
PLAINS FROM NM TO MT. LATEST H3 ANALYSIS SHOWS A 50 KT JET
LIFTING INTO CENTRAL WY. AN AREA OF SHOWERS AT NOSE OF THIS JET
MAX HAS DEVELOPED FROM NEAR CPR TO THE BIG HORNS. OTHER THAN THE
ACTIVITY IN OUR FAR SOUTH...OUR AREA REMAINS DRY AS HIGH CLOUD HAS
SUPPRESSED CONVECTION TO THIS POINT...DESPITE COOLING TEMPS ALOFT
UNDERNEATH LOW TO OUR SW.
MODELS AGREE IN THEIR DEVELOPMENT OF A WEAK MID LEVEL LOW IN OUR
EAST TONIGHT...AND THIS IS CONSISTENT WITH EXPECTED GRADUAL
EASTWARD SHIFT IN THE JET ALOFT. COMBINATION OF SYNOPTIC SCALE
FORCING WITH PWATS ON THE ORDER OF AN INCH SHOULD RESULT IN GOOD
COVERAGE OF SHOWER ACTIVITY TONIGHT. RAP HAS TRENDED A BIT FURTHER
WEST WITH THIS LOW THAN THE GFS/NAM...AND THIS SEEMS REASONABLE
GIVEN CURRENT JET POSITION...SO HAVE COVERED EVERYWHERE FROM
BILLINGS EAST WITH A LIKELY POP TONIGHT. BEARTOOTH FOOTHILLS
SHOULD ALSO BE FAVORED PER DEEPENING UPSLOPE FLOW. INSTABILITY
SEEMS SUFFICIENT FOR ISOLD EMBEDDED TSTMS...BUT FOR THE MOST PART
BELIEVE WE WILL SEE LIGHT TO MODERATE SHOWERS...ESPECIALLY
CONSIDERING THE EFFECTS OF CLOUD COVER THIS AFTERNOON...SO DO NOT
SEE A SIGNIFICANT HEAVY RAIN THREAT TONIGHT.
MID LEVEL LOW WILL GET CAUGHT UP IN SAGGING CANADIAN JET AND
SHIFT EAST INTO THE DAKOTAS AROUND 12Z SATURDAY...SO EXPECT
STRONGER FORCING TO EXIT OUR AREA TOMORROW MORNING. SFC FRONTAL
PASSAGE FROM THE NORTH AND WEAK Q-VECTOR CONVERGENCE ON BACK SIDE
OF DEPARTING LOW WILL ALLOW FOR SHOWER DEVELOPMENT TOMORROW.
COOLER TEMPS ALOFT AND DIURNAL HEATING SHOULD ALLOW FOR AN
INCREASED CHANCE OF TSTMS ON SATURDAY...THOUGH BY AFTERNOON WE
WILL SEE AFFECTS OF DRIER POST FRONTAL CANADIAN AIR AS NORTH WINDS
INCREASE. THERE IS A WINDOW OF OPPORTUNITY...ALBEIT A FAIRLY
SHORT ONE...FOR DOWNPOURS AND LOCALLY HEAVY RAINFALL AMOUNTS WITH
TOMORROWS CONVECTION. HIGHEST POPS WILL BE IN OUR SOUTH AND EAST
PER UPSLOPE FLOW AND TIMING OF FROPA. EXPECT ACTIVITY TO BE
GREATLY REDUCED BY EVENING AS DRIER AND MORE STABLE SFC RIDGE
BUILDS FROM THE NORTH. HAVE SCALED BACK POPS QUITE A BIT SATURDAY
NIGHT.
AS FOR RAINFALL AMOUNTS...BELIEVE MOST AREAS WILL RECEIVE LESS
THAN AN INCH BUT CANNOT RULE OUT LOCAL AMOUNTS THAT HIGH
ESPECIALLY IN OUR SOUTH AND EAST. AS FOR BILLINGS...LOOKS LIKE ON
THE ORDER OF A QUARTER INCH WITH A HALF INCH POSSIBLE IF A HEAVY
SHOWER HITS US JUST RIGHT TOMORROW. TAKE NOTE...THIS SYSTEM IS
NOTHING LIKE WE HAD LAST WEEKEND...NOR WILL WE SEE THE INCREDIBLE
PCPN AMOUNTS THAT EASTERN COLORADO HAS EXPERIENCED OVER THE PAST
COUPLE DAYS. DIFFERENT SET UP ENTIRELY.
SUNDAY LOOKS DRY WITH INCREASED E-SE WINDS AS SFC RIDGE SHIFTS
EAST. COULD BE SOME SHOWERS/ISOLD TSTMS OVER OUR WEST/SOUTHERN
MTNS AS WEAK SHORTWAVE INTERACTS WITH MOISTURE LINGERING OVER THE
NORTHERN GREAT BASIN.
AS FOR TEMPERATURES...NEXT TWO DAYS WILL BE COOLER...BUT WITH
TEMPS NEAR TO SLIGHTLY ABOVE MID SEPTEMBER NORMALS. LOOK FOR
HIGHS MAINLY IN THE 70S SATURDAY AND SUNDAY.
JKL
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MINIMAL CHANGES TO THE INHERITED LONG TERM FORECAST THIS
AFTERNOON...WITH MODELS IN CONTINUED GOOD AGREEMENT ON RELATIVELY
PROGRESSIVE WEATHER PATTERN. SOME TIMING DIFFERENCE REMAIN...BUT
DO NOT HAVE MUCH IMPACT ON THE OVERALL FORECAST. CHANGES CENTERED
AROUND INCREASING WINDS IN THE GAP FLOW AREAS AND WESTERN
FOOTHILLS AROUND LIVINGSTON AND BIG TIMBER... TO RESPOND TO
WEATHER SYSTEMS MOVING INTO AND OUT OF THE REGION.
STABLE CONDITIONS WILL CONTINUE INTO MONDAY...BUT CHANGE IS AGAIN
ON THE HORIZON. THE UPPER LEVEL RIDGING OVER THE AREA WILL BE
FLATTENED BY AN COLD FRONT THROUGH THE REGION MONDAY EVENING.
MONDAY WILL SEE WELL ABOVE AVERAGE TEMPERATURES AHEAD OF THE
FRONT...WITH SHOWERS AND THUNDERSTORMS DEVELOPING FROM WEST TO
EAST THROUGH THE EVENING AND NIGHT. SLIGHT CHANCE POPS WILL
CONTINUE THROUGH THE DAY TUESDAY...AS THE UPPER LEVEL TROD PASSES
EASTWARD. SO FAR MOISTURE AVAILABILITY APPEARS SOMEWHAT
LIMITED...COMPARED TO RECENT WEATHER...BUT CANNOT RULE OUT
DEVELOPMENT WITH STRENGTH OF THE SYSTEM. TEMPS WILL BE A BIT
COOLER TUESDAY...WITH EXPECTED INTERVENING CLOUD COVER AND SHOWER
ACTIVITY. THE FORECAST DRIES OUT SIGNIFICANTLY FOR THE REMAINDER
OF THE PERIOD FOLLOWING THIS WEATHER SYSTEM. TEMPS WILL FALL TO
AROUND SEASONAL AVERAGE FOR WEDNESDAY AND THURSDAY BEHIND THE
WEATHER SYSTEM...BUT JUMP BACK WELL ABOVE NORMAL FOR FRIDAY...AS
UPPER LEVEL RIDGING DEVELOPS ACROSS THE REGION. AAG
&&
.AVIATION...
SHOWERS ARE DEVELOPING ON THE BIGHORN MOUNTAINS...WITH INCREASING
CLOUDINESS OVER WESTERN MOUNTAINS. VFR CONDITIONS OVER CENTRAL AND
EASTERN ROUTES THIS EVENING...BUT WILL GIVE WAY TO LOCALIZED MVFR
OR LOWER CONDITIONS OVERNIGHT AS SHOWERS AND THUNDERSTORMS SPREAD
EASTWARD. A FEW STORMS MAY PRODUCE LOCAL LIFR CONDITIONS...IN
REDUCED VIS FROM HEAVY RAIN. INCREASING MOUNTAINS TOP OBSCURATION
CAN BE EXPECTED BY THIS EVENING AND OVERNIGHT. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 062/076 052/078 055/085 057/081 054/073 049/073 049/083
65/T 20/B 01/U 23/T 32/W 11/U 00/U
LVM 054/073 047/078 050/085 049/078 045/072 042/072 041/079
44/T 22/T 22/T 23/T 32/W 21/B 02/T
HDN 058/076 050/079 051/086 054/083 052/076 048/076 050/083
66/T 21/B 11/U 13/T 32/W 11/U 00/U
MLS 061/077 050/076 053/084 058/083 056/074 050/074 052/083
66/T 10/U 01/U 12/T 33/W 11/B 00/U
4BQ 056/076 047/076 050/083 053/084 053/076 047/075 051/083
66/T 31/B 11/U 11/U 22/W 11/U 00/U
BHK 057/075 046/071 047/078 053/082 054/074 047/072 049/081
56/T 20/U 01/U 11/U 33/W 21/U 00/U
SHR 055/072 048/074 048/082 051/082 050/075 044/073 047/080
66/T 32/T 21/U 11/U 33/W 11/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
833 AM MDT FRI SEP 13 2013
.UPDATE...
OVERALL FORECAST APPEARS TO BE IN GOOD SHAPE SO HAVE MADE ONLY
FEW CHANGES THIS MORNING. AREA OF SHOWERS IN CENTRAL WY ASSOCIATED
WITH SHORTWAVE LIFTING OUT OF THE CENTRAL ROCKIES IS CURRENTLY
SPREADING INTO THE SOUTHERN BIG HORNS. RAP SEEMS TO HAVE A FAIR
HANDLING OF THIS...WITH BACKING MID LEVEL FLOW EXPECTED TO
TRANSLATE NORTHWARD OVER THE NEXT SEVERAL HOURS. MOISTURE
ADVECTION IN ADDITION TO DEEPENING UPSLOPE FLOW SHOULD YIELD AN
ENHANCED CHANCE OF SHOWERS ALONG THE EAST SIDE OF THE BIG HORNS
INCLUDING SHERIDAN BY LATE AFTERNOON AND CONTINUING INTO THE
EVENING. HAVE RAISED POPS AND QPF AMOUNTS IN THIS AREA.
OTHERWISE...COOLING UPPER LEVEL TEMPS IN RESPONSE TO NORTHWARD
MOVING UPPER LOW ALONG WITH DIURNAL HEATING AND WEAK Q-VECTOR
CONVERGENCE SHOULD RESULT IN SCATTERED SHOWERS AND SOME
THUNDERSTORMS THIS AFTERNOON AND EVENING. NO SEVERE WEATHER
EXPECTED BUT ANY STRONGER CELLS WILL CERTAINLY PRODUCE LOCALLY
HEAVY RAIN AS PWATS GET PUSHED UP TO AROUND AN INCH...CONSISTENT
WITH UPSTREAM 12Z RAOBS. JKL
&&
.SHORT TERM...VALID FOR TDY AND SAT...
SCATTERED SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN ARE EXPECTED
TODAY THROUGH SATURDAY AS A WEAKENING UPPER-LEVEL LOW WORKS NORTH
INTO THE REGION.
TODAY...A MID-LEVEL VORTICITY MAXIMUM OBSERVED ACROSS THE CENTRAL
ROCKIES EARLY THIS MORNING WILL MOVE NORTH AND REACH THE SOUTHERN
PARTS OF MT BY LATE AFTERNOON. THIS SHOULD FOSTER SOME CONVECTION
AS DEEP-LAYER MOISTURE INCREASES ON SOUTHERLY FLOW...BRINGING THE
AIR MASS WITH NEARLY ONE INCH OF PRECIPITABLE WATER CAPTURED WITH
THE 00 UTC RIVERTON SOUNDING INTO THE AREA. ISOLATED TO SCATTERED
SHOWERS SHOULD DEVELOP BY LATE AFTERNOON...WITH EARLIER FORMATION
AND GREATER COVERAGE WORTHY OF LIKELY POPS IN THE BIG HORNS BASED
ON RECENT HIGH-RESOLUTION MODEL SIMULATIONS. SCATTERED STORMS ARE
IN THE FORECAST FROM THE BEARTOOTH/ABSAROKA MOUNTAINS EASTWARD TO
SHERIDAN AS FORECAST SOUNDINGS SHOW 500 J/KG OF MUCAPE OVER THOSE
AREAS AFTER 18 UTC. THE CALIBRATED THUNDERSTORM PROBABILITIES OFF
OF THE 03 UTC SREF ALSO SUPPORT THAT IDEA. FURTHER NORTH...SLIGHT
CHANCES OF THUNDER WITH THE SHOWERS SHOULD SUFFICE IN PLACES LIKE
BILLINGS AND MILES CITY...WHERE MID-LEVEL LAPSE RATES ARE WEAKER.
TONIGHT...A MODERATE BATCH OF 500-300 HPA Q-VECTOR CONVERGENCE IS
EXPECTED TO BE OVER THE AREA...SO SOME POPS ARE IN PLAY ALL NIGHT
EVEN THOUGH CONVECTION SHOULD DIMINISH A BIT DIURNALLY. LOWS WILL
PROBABLY NOT FALL BELOW 60 F IN SOME LOWER ELEVATIONS WITH CLOUDS
INHIBITING SURFACE COOLING.
SAT...WEAK FORCING WILL REMAIN IN PLACE ALOFT...AND THE MID-LEVEL
LAPSE RATES ACTUALLY STEEPEN A BIT. IN ADDITION...A COLD FRONT IS
EXPECTED TO DROP SOUTH INTO THE AREA FROM THE NORTH...WHICH COULD
ENHANCE LOW-LEVEL VERTICAL MOTION IN SUPPORT OF CONVECTION. WINDS
WILL EVEN TURN TO AN UPSLOPE DIRECTION BEHIND THE FRONT. WE COULD
ULTIMATELY NEED LIKELY POPS FOR MORE OF THE LOWER ELEVATIONS ONCE
RUN-TO-RUN WOBBLES IN THE POSITION OF FORCING TIED TO A WEAKENING
WAVE SETTLE DOWN. FINALLY...NOTE THAT TEMPERATURES WILL BE HIGHLY
DEPENDENT ON CLOUDS AND PRECIPITATION TOO...WHICH MEANS HIGHS MAY
END UP MUCH COOLER THAN ADVERTISED IN SOME AREAS. SCHULTZ
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
MODELS GENERALLY IN GOOD AGREEMENT OVER BASIC PATTERNS AFFECTING
THE LONG TERM FORECAST. THERE ARE SOME TIMING DIFFERENCES WHICH
OCCUR WITH A SHORT WAVE EXCITING NORTHERN ROCKIES AT THE MIDDLE
PART OF NEXT WEEK...BUT THESE ARE RELATIVELY MINOR AND DO NOT
AFFECT THE OVERALL OUTCOME OF FORECAST HIGHS...LOWS AND POPS. MAIN
CHANGES FOR THIS FORECAST PACKAGE WERE TO LOWER OR REMOVE POPS
AFTER MIDWEEK.
BEGINNING SUNDAY...WE WILL BE UNDER LOW LEVEL EASTERLY FLOW BEHIND
SATURDAY NIGHTS COLD FRONT. SO STABLE CONDITIONS AND SEASONAL
TEMPERATURES SHOULD PREVAIL. WE EXPECT TO QUICKLY WARM UP MONDAY
BACK INTO THE 80S FOR MANY AREAS AS A LARGE RIDGE ALOFT CONTROLS
THE WEATHER. A FAST MOVING WEATHER SYSTEM WILL QUICKLY SWEEP INTO
THE NORTHERN ROCKIES TUESDAY ON THE NOSE OF A 90KT MID LEVEL JET.
THIS APPEARS SOMEWHAT FALL LIKE TO ME...BUT IS ROBUST ENOUGH TO
PRODUCE THUNDERSTORMS ALONG WITH SHOWERS AND WINDY CONDITIONS.
BEHIND THIS SYSTEM...LOOK FOR A RETURN TO SEASONAL TEMPERATURES
AND MAINLY DRY CONDITIONS AS FLOW ALOFT BECOMES MORE ZONAL IN
NATURE...A DEFINITE SIGN OF AUTUMN ON ITS WAY. BT
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL INTO THE AFTERNOON HOURS. SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER
TERRAIN BY EARLY AFTERNOON...AND SPREAD TO THE LOWER ELEVATIONS
BY EVENING. A FEW STORMS MAY PRODUCE LOCAL LIFR CONDITIONS THIS EVENING
AND OVERNIGHT...DUE TO REDUCED VIS IN HEAVY RAIN. OCCASIONAL
MOUNTAINS TOP OBSCURATION IS EXPECTED BY THIS EVENING AS WELL. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 083 061/075 055/077 055/085 057/081 054/073 049/073
3/T 35/T 51/B 11/U 23/T 32/W 11/U
LVM 084 054/072 048/078 050/085 049/078 045/072 042/072
3/T 45/T 52/T 12/T 23/T 32/W 21/B
HDN 084 057/076 051/079 052/086 054/083 052/076 048/076
3/T 45/T 51/B 11/U 13/T 32/W 11/U
MLS 084 061/077 052/076 053/084 058/083 056/074 050/074
2/T 35/T 31/U 01/U 12/T 33/W 11/B
4BQ 081 056/076 049/076 050/083 053/084 053/076 047/075
3/T 55/T 52/T 11/U 11/U 22/W 11/U
BHK 082 057/075 048/072 048/078 053/082 054/074 047/072
1/N 35/T 31/U 01/U 11/U 33/W 21/U
SHR 078 055/073 048/074 048/082 051/082 050/075 044/073
6/T 65/T 52/T 11/U 11/U 33/W 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
408 PM CDT FRI SEP 13 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 400 PM CDT FRI SEP 13 2013
ALOFT: UPR-LVL FLOW IS COMPLEX. A CUT-OFF LOW IS NEAR SLC AND WILL
REMAIN THERE THRU 00Z/SUN. A SMALL SUBTROPICAL HIGH WAS OVER TX WITH
ITS RIDGE EXTENDING N THRU THE PLAINS. A SHRTWV TROF WAS OVER WY AND
LIFTING N. THIS TROF WILL CONT INTO THE DAKOTAS TNGT-SAT AND
/COMBINED WITH A SIGNIFICANT TROF DROPPING THRU CNTRL CANADA/ WILL
FORCE THE RIDGE TO DEAMPLIFY AND SHIFT E.
SFC: HIGH PRES WAS OVER THE UPR MIDWEST...WHILE A WEAK SFC LOW WAS
OVER MT...ALONG A SFC TROF. SFC WINDS WILL GRADUALLY SHIFT FROM SE
TO S TNGT AND THEN TO SW TOMORROW. THRU 00Z/SUN...THE HIGH WILL
MIGRATE TO THE MID-ATLANTIC STATES...AND THE TROF WILL SETTLE INTO
NRN AND WRN NEB...AS THE NEXT CANADIAN COOL FRONT PRESSES INTO THE
NRN PLAINS.
REST OF THIS AFTN: CLOUDY S AND W OF THE TRI-CITIES WITH THE THREAT
OF PATCHY -RA W OF HWY 183 ENDING. FROM THE TRI-CITIES N AND E...
SLOWLY INCREASING CLOUDS.
RADAR TRENDS: THE HI-RES RAP AND THE 06Z WRF-NMM HAVE DONE A VERY
NICE JOB WITH THEIR SIMULATED REFLECTIVITY TODAY AND CONTS TO
SUPPORT CURRENT TRENDS. THIS BAND OF -RA WILL CONT LIFTING N WHILE
GRADUALLY DISSIPATING AS IT PROGRESSES INTO DRIER AIR. THE FCST AREA
COULD THEN BE MOSTLY DRY THE REST OF THE NGT.
THE 12Z NAM WAS WAY TOO DRY WITH ITS 12 HR QPF ENDING AT 00Z VS
REALITY.
THE WY SHRTWV TROF WILL TAKE THE BEST FORCING FOR LIFT/PCPN INTO THE
DAKOTAS TNGT. THAT IS ALSO WHERE THE NOSE OF THE LLJ WILL BE AIMED.
CAN/T COMPLETELY RULE OUT A SHWR OR TWO WITHIN GENTLE ISENTROPIC
LIFT.
WINDS BACKED TO THE S ON THE 12Z LBF SOUNDING AND MSTR IN THE
850-500 MB LAYER INCREASED SUBSTANTIALLY. THIS IS SUPPORTING THE
ON-GOING -RA OVER WRN/SRN PARTS OF THE FCST AREA...WHICH IS AT THE
LEADING EDGE OF THE GRADIENT OF HIGHER PW. BACKING WINDS AT ALL LVLS
WILL SHOVE THE MAX PW AXIS INTO THE FCST AREA TNGT.
WHILE MUCH OF THE FCST AREA HAS SEEN THE DECENT RAINFALL IN THE PAST
3 DAYS /MOSTLY ALONG AND S OF I-80/...THE SAD FACT IS MUCH OF THE
HIGH PW AIR MAY END UP BEING WASTED. PROSPECTS FOR RAIN ARE NIL TNGT
AND NOT LOOKING GOOD TOMORROW EXCEPT IN VERY ISOLATED POCKETS. WHILE
THE SFC TROF GETS CLOSE...AND THE TAIL END OF THE DAKOTA/S SHRTWV
TROF WILL BE OVER THE PANHANDLE ...THERE ISN/T MUCH FORCING ALOFT.
SO AM NOT EXPECTING MUCH DURING THE DAYLGT HRS OF SAT. WE CAN HOLD
OUT HOPE FOR SAT NGT.
TNGT: MAINLY CLOUDY. CAN/T ENTIRELY RULE OUT A SHWR OR TWO BUT MOST
LOCATIONS REMAIN DRY.
ONE CONCERN IS WHERE CLOUDS ARE CURRENTLY THIN FROM THE TRI-CITIES N
AND E. DWPTS ARE LOW THERE AND TEMPS WILL DROP OFF RATHER SHARPLY
THIS EVNG. FOR NOW ANTICIPATED THAT CLOUDS WILL INCREASE IN TIME TO
ARREST DROP-OFF WITH LOWS FAIRLY UNIFORM OVER THE ENTIRE FCST AREA
/MID-UPR 50S/. LOWS N AND E OF THE TRI-CITIES ARE ONLY AVERAGE
CONFIDENCE.
SAT: M/CLOUDY. TEMPS ARE LOW CONFIDENCE DUE TO CLOUD COVER
UNCERTAINTY. HIGHS WERE LOWERED 1-2F. A HIGH-PW AIR MASS WILL BE IN
PLACE /2 STANDARD DEVIATIONS ABOVE NORMAL/. EXPECT SOME AREAS MAY
THIN ENOUGH FOR MARGINAL DESTABILIZATION AND ISOLD-SCT TSTM
DEVELOPMENT...MUCH LIKE WHAT IS OCCURRING OVER SERN CO AND THE TX
PANHANDLE ATTM.
MLCAPE WILL BE LESS THAN 1000 J/KG. INDIVIDUAL CELL MVMT WILL BE NE
AROUND 25 KTS. DEEP LAYER SHEAR WILL BE 15-20 KTS. NO SVR WX IS
EXPECTED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 400 PM CDT FRI SEP 13 2013
SATURDAY NIGHT...AN UPPER LEVEL TROUGH WITH AN ACCOMPANYING COLD
FRONT WILL SWING THROUGH THE FORECAST AREA BRINGING WITH IT OUR BEST
CHANCE OF SHOWERS AND THUNDERSTORMS. INSTABILITY WILL BE WEAK AND
THUS AM NOT EXPECTING ANY KIND OF SEVERE WEATHER...BUT RATHER
PERHAPS JUST A GENERAL LINE OR SEVERAL LINES OF SHOWERS AND
THUNDERSTORMS THAT WILL TRACK ACROSS THE AREA.
SUNDAY AND MONDAY...THE COOL FRONT WILL TRACK ACROSS KANSAS ON
SUNDAY AND WATCH OUT OVER OKLAHOMA BY SUNDAY NIGHT/MONDAY MORNING.
RAIN CHANCES WILL DECREASE ACROSS OUR FORECAST AREA WITH BETTER
CHANCES OF SHOWERS AND THUNDERSTORMS FURTHER SOUTH FOLLOWING THE
FRONT. HAVE DECREASED RAIN CHANCES ACROSS OR FORECAST AREA DURING
THIS PERIOD DUE TO THE QUICK PROGRESS OF THE FRONT AND AM NOW EVEN
GOING DRY FOR MONDAY ACROSS NEBRASKA ZONES WITH JUST A SLIGHT CHANCE
OF SHOWERS ACROSS NORTHERN KANSAS. TEMPERATURES WILL BE COOLER
BEHIND THE COLD FRONT RANGING FROM AROUND 70 NORTH TO THE MID 70S
OVER NORTHERN KANSAS.
MONDAY NIGHT/TUESDAY...A MINOR SHORTWAVE WILL TRACK NORTHEAST ACROSS
OUR FORECAST AREA AND A WEAK WARM FRONT WILL LIFT BACK THROUGH.
THIS WILL RESULT IN GENERALLY LOW END RAIN CHANCES. TEMPERATURES
WILL START TO WARM UP AND MAY ONCE AGAIN BE BACK TO AROUND 80 BY
TUESDAY AFTERNOON.
WEDNESDAY THROUGH FRIDAY...AN UPPER RIDGE WILL TRY TO BUILD ACROSS
THE PLAINS...BUT WILL NOT BE OVERLY STRONG SO NO REPEAT OF THE 90
DEGREE HEAT. EXPECT MOST AREAS WILL BE DRY WITH ABOVE NORMAL
TEMPERATURES IN THE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1246 PM CDT FRI SEP 13 2013
REST OF THIS AFTN: VFR WITH BKN 25K FT CIRRUS AND SCT 8-15K MID-
LVL CLOUDS. SSE WINDS BELOW 10 KTS.
TNGT: VFR WITH MID-LVL CIGS CONTINUING TO CASCADE DOWN TO AROUND
7K FT. SSE WINDS BELOW 10 KTS. COULD BE A TOUCH OF -RA AFTER 09Z
BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE TAF.
SAT THRU 18Z: VFR FOR NOW...BUT THERE IS POTENTIAL FOR CIGS TO
CONTINUE DEGRADING TO MVFR. SOME -RA IS ALSO POSSIBLE. WINDS WILL
SHIFT TO S AND GUST UP TO 19 KTS AFTER 16Z.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: LOW
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...WESELY
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1246 PM CDT FRI SEP 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT FRI SEP 13 2013
TODAY AND TONIGHT...THE MODELS APPEAR TO BE TOO FAST AND AGGRESSIVE
LIFTING THE AREA OF RAIN ACROSS NWRN KS/NERN COLO THROUGH THE FCST
AREA TODAY AND TONIGHT. SO THE FORECAST SLOWS THIS BY 3 HOURS WHICH
MAY NOT BE ENOUGH. OTHERWISE...THE CLOUD SHIELD ACROSS SWRN NEB
SHOULD SPREAD SLOWLY NORTH TODAY AND TONIGHT. THE FORECAST ATTEMPTS
TO MARK UP TEMPS FOR WARMER HIGHS AS THE CLOUDS AND RAIN WILL LIKELY
BE DELAYED BY SEVERAL HOURS AND MAY NOT REACH INTERSTATE 80 UNTIL
LATE THIS AFTERNOON.
MODEL BLENDED QPF PRODUCED AROUND 1/3 OF AN INCH ACROSS SWRN NEB TO
0.05 INCHES ACROSS ERN ZONES. THE RAP MODEL LIFTS THE RAIN NORTH
VERY QUICKLY AND DRIES IT OUT AT THE SAME TIME WHICH IS LIKELY A
RESULT OF DRY AIR AT THE LOWER LEVELS. THE HRRR MODEL IS WAY TOO
FAST AND A PLUME OF ALL MODEL SOLNS FOR NORTH PLATTE SHOW A VERY
WIDE SPREAD OF QPF TOTALS FROM 1/3 OF AN INCH TO A TRACE. THUS THE
RAIN CHANCES ACROSS MUCH THE FCST AREA EXCEPTING FAR SWRN NEB ARE
UNCERTAIN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CDT FRI SEP 13 2013
FORECAST CONFIDENCE REMAINS AVERAGE THROUGH THE WEEKEND WITH
DECENT CONSISTENCY DISPLAYED FROM THE LONG RANGE SOLUTIONS. FOR
SATURDAY...RAIN CHANCES DO NOT APPEAR TO BE AS WIDESPREAD AS THE
BULK OF THE QG FORCING AND ASSOCIATED WEAKENING UPPER LEVEL LOW IS
DIRECTED TO THE NORTH AND WEST OF THE CWA...BUT INCREASING
ATMOSPHERIC INSTABILITY WITH SUFFICIENT MOISTURE WOULD ALLOW FOR
AT LEAST A CONTINUED MENTION OF STORMS THROUGH THE DAY. BETTER
CHANCES HOWEVER APPEAR TO ARRIVE LATE SATURDAY INTO EARLY SUNDAY
AS A WEAK DISTURBANCE WORKS ON A PASSING FRONTAL BOUNDARY...SHOWER
AND THUNDERSTORM CHANCES WILL REMAIN HIGHEST ALONG OUR SOUTHERN
AND EASTERN BORDERS AS THE FRONT SETTLES ACROSS KANSAS. WITH HIGH
PRESSURE BUILDING SOUTH ACROSS THE NORTHERN HIGH PLAINS AND INTO
THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY...DRIER CONDITIONS
ARE ANTICIPATED FOR MUCH OF THE REGION. THERE WILL BE A SHARP
DIVIDING LINE HOWEVER AS A CONTINUED TAP OF MOIST MONSOONAL AIR
DRIVES NORTH THROUGH THE SOUTHERN PLAINS. A RECENT TREND OF THE
LONGER RANGE SOLUTIONS IS TO SETTLE THE FRONT FURTHER SOUTH ACROSS
SOUTHERN/CENTRAL KANSAS WITH DRIER AIR /VOID OF PRECIPITATION/
ACROSS MOST IF NOT ALL LOCATIONS ACROSS THE CWA. DID NOT WANT TO
ENTIRELY PULL POPS YET ON SUNDAY AND INTO MONDAY...THUS WILL LOWER
TO A SLIGHT CHANCE MENTION FOR MOST PLACES...BUT FEEL WE COULD GO
LOWER YET. WITH THE DRIER AIR WORKING SOUTH...CONDITIONS WILL BE
PLEASANTLY COOL ON SUNDAY...WITH HIGHS TOPPING OUT IN THE UPPER
60S TO LOW 70S. LOOKING AHEAD TO EARLY NEXT WEEK...THE MODEL
CONSENSUS DEVELOPS A BROAD RIDGE ACROSS THE CENTRAL CONUS WITH
PERIODIC SHORTWAVES SUPPRESSING ITS STRENGTH. A GENERAL WARMING
TREND IS THEN SHOWN...WITH HIGHS RETURNING BACK INTO THE 80S AS
EARLY AS TUESDAY...AND LOWS FALLING INTO THE UPPER 50S FOR MOST
PLACES. PERIODIC STORM CHANCES ARE IN STORE FOR NEXT WEEK...MAINLY
ACROSS EASTERN PORTIONS OF THE CWA AS A FRONT STALLS AND PERIODIC
WAVES PASS THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1246 PM CDT FRI SEP 13 2013
BATTLE BETWEEN MOIST AIR/SHOWERS LIFTING NORTHEAST TOWARDS A DRY
HIGH PRESSURE. EXPECTING SOME SHOWERS TO CONTINUE ACROSS SW
NEB...LIFTING TOWARDS THE KLBF TERMINAL...HOWEVER THINK KVTN WILL
REMAIN DRY. IN ADDITION TO THE CHANCE FOR RAIN...LOWERING CIGS ARE
EXPECTED. MVFR CIGS ARE LIKELY WITHIN SHOWERS FOR KLBF. SOUTHWEST
NEBRASKA WILL SEE LOWER CIGS...LESS THAN 1K FT...AS SE WINDS BRING
UPSLOPE FLOW AND AID IN LOWERING THE CIG. BY TOMORROW MORNING
CONDITIONS IMPROVE WITH CIGS RISING AND THE CHANCE FOR RAIN
DIMINISHING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...MASEK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
621 AM CDT FRI SEP 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT FRI SEP 13 2013
TODAY AND TONIGHT...THE MODELS APPEAR TO BE TOO FAST AND AGGRESSIVE
LIFTING THE AREA OF RAIN ACROSS NWRN KS/NERN COLO THROUGH THE FCST
AREA TODAY AND TONIGHT. SO THE FORECAST SLOWS THIS BY 3 HOURS WHICH
MAY NOT BE ENOUGH. OTHERWISE...THE CLOUD SHIELD ACROSS SWRN NEB
SHOULD SPREAD SLOWLY NORTH TODAY AND TONIGHT. THE FORECAST ATTEMPTS
TO MARK UP TEMPS FOR WARMER HIGHS AS THE CLOUDS AND RAIN WILL LIKELY
BE DELAYED BY SEVERAL HOURS AND MAY NOT REACH INTERSTATE 80 UNTIL
LATE THIS AFTERNOON.
MODEL BLENDED QPF PRODUCED AROUND 1/3 OF AN INCH ACROSS SWRN NEB TO
0.05 INCHES ACROSS ERN ZONES. THE RAP MODEL LIFTS THE RAIN NORTH
VERY QUICKLY AND DRIES IT OUT AT THE SAME TIME WHICH IS LIKELY A
RESULT OF DRY AIR AT THE LOWER LEVELS. THE HRRR MODEL IS WAY TOO
FAST AND A PLUME OF ALL MODEL SOLNS FOR NORTH PLATTE SHOW A VERY
WIDE SPREAD OF QPF TOTALS FROM 1/3 OF AN INCH TO A TRACE. THUS THE
RAIN CHANCES ACROSS MUCH THE FCST AREA EXCEPTING FAR SWRN NEB ARE
UNCERTAIN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CDT FRI SEP 13 2013
FORECAST CONFIDENCE REMAINS AVERAGE THROUGH THE WEEKEND WITH
DECENT CONSISTENCY DISPLAYED FROM THE LONG RANGE SOLUTIONS. FOR
SATURDAY...RAIN CHANCES DO NOT APPEAR TO BE AS WIDESPREAD AS THE
BULK OF THE QG FORCING AND ASSOCIATED WEAKENING UPPER LEVEL LOW IS
DIRECTED TO THE NORTH AND WEST OF THE CWA...BUT INCREASING
ATMOSPHERIC INSTABILITY WITH SUFFICIENT MOISTURE WOULD ALLOW FOR
AT LEAST A CONTINUED MENTION OF STORMS THROUGH THE DAY. BETTER
CHANCES HOWEVER APPEAR TO ARRIVE LATE SATURDAY INTO EARLY SUNDAY
AS A WEAK DISTURBANCE WORKS ON A PASSING FRONTAL BOUNDARY...SHOWER
AND THUNDERSTORM CHANCES WILL REMAIN HIGHEST ALONG OUR SOUTHERN
AND EASTERN BORDERS AS THE FRONT SETTLES ACROSS KANSAS. WITH HIGH
PRESSURE BUILDING SOUTH ACROSS THE NORTHERN HIGH PLAINS AND INTO
THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY...DRIER CONDITIONS
ARE ANTICIPATED FOR MUCH OF THE REGION. THERE WILL BE A SHARP
DIVIDING LINE HOWEVER AS A CONTINUED TAP OF MOIST MONSOONAL AIR
DRIVES NORTH THROUGH THE SOUTHERN PLAINS. A RECENT TREND OF THE
LONGER RANGE SOLUTIONS IS TO SETTLE THE FRONT FURTHER SOUTH ACROSS
SOUTHERN/CENTRAL KANSAS WITH DRIER AIR /VOID OF PRECIPITATION/
ACROSS MOST IF NOT ALL LOCATIONS ACROSS THE CWA. DID NOT WANT TO
ENTIRELY PULL POPS YET ON SUNDAY AND INTO MONDAY...THUS WILL LOWER
TO A SLIGHT CHANCE MENTION FOR MOST PLACES...BUT FEEL WE COULD GO
LOWER YET. WITH THE DRIER AIR WORKING SOUTH...CONDITIONS WILL BE
PLEASANTLY COOL ON SUNDAY...WITH HIGHS TOPPING OUT IN THE UPPER
60S TO LOW 70S. LOOKING AHEAD TO EARLY NEXT WEEK...THE MODEL
CONSENSUS DEVELOPS A BROAD RIDGE ACROSS THE CENTRAL CONUS WITH
PERIODIC SHORTWAVES SUPPRESSING ITS STRENGTH. A GENERAL WARMING
TREND IS THEN SHOWN...WITH HIGHS RETURNING BACK INTO THE 80S AS
EARLY AS TUESDAY...AND LOWS FALLING INTO THE UPPER 50S FOR MOST
PLACES. PERIODIC STORM CHANCES ARE IN STORE FOR NEXT WEEK...MAINLY
ACROSS EASTERN PORTIONS OF THE CWA AS A FRONT STALLS AND PERIODIC
WAVES PASS THROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 613 AM CDT FRI SEP 13 2013
THE AREA OF RAIN ACROSS NERN COLO/WRN KS IS EXPECTED TO LIFT NORTH
THROUGH THE FCST AREA TODAY AND TONIGHT PRODUCING AREAS OF
MVFR/IFR. THIS AREA OF RAIN IS EXPECTED TO HAVE THE LEAST IMPACT
ACROSS NERN NEB WHERE HIGH PRESSURE AND DRY AIR AT THE LOWER
LEVELS MAY EVAPORATE THE RAIN BEFORE REACHING THE GROUND.
UPSLOPE WINDS TODAY AND TONIGHT MAY KEEP CIGS MVFR OR LOWER EVEN
AFTER THE RAIN ENDS ACROSS WRN NEB...HIGHWAY 61 AND WEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
340 AM CDT FRI SEP 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT FRI SEP 13 2013
TODAY AND TONIGHT...THE MODELS APPEAR TO BE TOO FAST AND AGGRESSIVE
LIFTING THE AREA OF RAIN ACROSS NWRN KS/NERN COLO THROUGH THE FCST
AREA TODAY AND TONIGHT. SO THE FORECAST SLOWS THIS BY 3 HOURS WHICH
MAY NOT BE ENOUGH. OTHERWISE...THE CLOUD SHIELD ACROSS SWRN NEB
SHOULD SPREAD SLOWLY NORTH TODAY AND TONIGHT. THE FORECAST ATTEMPTS
TO MARK UP TEMPS FOR WARMER HIGHS AS THE CLOUDS AND RAIN WILL LIKELY
BE DELAYED BY SEVERAL HOURS AND MAY NOT REACH INTERSTATE 80 UNTIL
LATE THIS AFTERNOON.
MODEL BLENDED QPF PRODUCED AROUND 1/3 OF AN INCH ACROSS SWRN NEB TO
0.05 INCHES ACROSS ERN ZONES. THE RAP MODEL LIFTS THE RAIN NORTH
VERY QUICKLY AND DRIES IT OUT AT THE SAME TIME WHICH IS LIKELY A
RESULT OF DRY AIR AT THE LOWER LEVELS. THE HRRR MODEL IS WAY TOO
FAST AND A PLUME OF ALL MODEL SOLNS FOR NORTH PLATTE SHOW A VERY
WIDE SPREAD OF QPF TOTALS FROM 1/3 OF AN INCH TO A TRACE. THUS THE
RAIN CHANCES ACROSS MUCH THE FCST AREA EXCEPTING FAR SWRN NEB ARE
UNCERTAIN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CDT FRI SEP 13 2013
FORECAST CONFIDENCE REMAINS AVERAGE THROUGH THE WEEKEND WITH
DECENT CONSISTENCY DISPLAYED FROM THE LONG RANGE SOLUTIONS. FOR
SATURDAY...RAIN CHANCES DO NOT APPEAR TO BE AS WIDESPREAD AS THE
BULK OF THE QG FORCING AND ASSOCIATED WEAKENING UPPER LEVEL LOW IS
DIRECTED TO THE NORTH AND WEST OF THE CWA...BUT INCREASING
ATMOSPHERIC INSTABILITY WITH SUFFICIENT MOISTURE WOULD ALLOW FOR
AT LEAST A CONTINUED MENTION OF STORMS THROUGH THE DAY. BETTER
CHANCES HOWEVER APPEAR TO ARRIVE LATE SATURDAY INTO EARLY SUNDAY
AS A WEAK DISTURBANCE WORKS ON A PASSING FRONTAL BOUNDARY...SHOWER
AND THUNDERSTORM CHANCES WILL REMAIN HIGHEST ALONG OUR SOUTHERN
AND EASTERN BORDERS AS THE FRONT SETTLES ACROSS KANSAS. WITH HIGH
PRESSURE BUILDING SOUTH ACROSS THE NORTHERN HIGH PLAINS AND INTO
THE UPPER MISSISSIPPI RIVER VALLEY ON SUNDAY...DRIER CONDITIONS
ARE ANTICIPATED FOR MUCH OF THE REGION. THERE WILL BE A SHARP
DIVIDING LINE HOWEVER AS A CONTINUED TAP OF MOIST MONSOONAL AIR
DRIVES NORTH THROUGH THE SOUTHERN PLAINS. A RECENT TREND OF THE
LONGER RANGE SOLUTIONS IS TO SETTLE THE FRONT FURTHER SOUTH ACROSS
SOUTHERN/CENTRAL KANSAS WITH DRIER AIR /VOID OF PRECIPITATION/
ACROSS MOST IF NOT ALL LOCATIONS ACROSS THE CWA. DID NOT WANT TO
ENTIRELY PULL POPS YET ON SUNDAY AND INTO MONDAY...THUS WILL LOWER
TO A SLIGHT CHANCE MENTION FOR MOST PLACES...BUT FEEL WE COULD GO
LOWER YET. WITH THE DRIER AIR WORKING SOUTH...CONDITIONS WILL BE
PLEASANTLY COOL ON SUNDAY...WITH HIGHS TOPPING OUT IN THE UPPER
60S TO LOW 70S. LOOKING AHEAD TO EARLY NEXT WEEK...THE MODEL
CONSENSUS DEVELOPS A BROAD RIDGE ACROSS THE CENTRAL CONUS WITH
PERIODIC SHORTWAVES SUPPRESSING ITS STRENGTH. A GENERAL WARMING
TREND IS THEN SHOWN...WITH HIGHS RETURNING BACK INTO THE 80S AS
EARLY AS TUESDAY...AND LOWS FALLING INTO THE UPPER 50S FOR MOST
PLACES. PERIODIC STORM CHANCES ARE IN STORE FOR NEXT WEEK...MAINLY
ACROSS EASTERN PORTIONS OF THE CWA AS A FRONT STALLS AND PERIODIC
WAVES PASS THROUGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1250 AM CDT FRI SEP 13 2013
SHOWERS AND THUNDERSTORMS IN SOUTHWEST NEBRASKA ARE EXPECTED TO
REMAIN SOUTH OF AN OGA-LXN LINE TONIGHT THROUGH AT LEAST LATE FRIDAY
MORNING. CEILING IN THAT AREA OF NEBRASKA TONIGHT WILL CONTINUE TO
BE BELOW 3000 FEET AGL AND MAY GO BELOW 1000 FEET AGL. SOME CEILINGS
AT OR BELOW 4000 FEET AGL ARE EXPECTED TO REACH LBF AND MHN BY
12Z...BUT IT IS UNLIKELY THAT THEY WILL BE ANY LOWER THAN 4000 FEET.
SHOWERS AND THUNDERSTORMS WILL SPREAD NORTHEAST INTO SOUTHWEST
NEBRASKA THROUGH THE DAY FRIDAY...BUT THEY WILL PROBABLY NOT REACH
MHN-LBF UNTIL 00Z OR LATER. AFTER 00Z...THE PROBABILITY FOR LBF IS
EXPECTED TO BE 40-45 PERCENT. WITH MODERATE CONFIDENCE SUCH AS
THAT...WE BELIEVE THAT A MENTION OF AT LEAST VCTS IS WARRANTED FOR
THE LBF TERMINAL FORECAST.
BEYOND 06Z SATURDAY...THE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
MOVE ACROSS CENTRAL AND NORTH CENTRAL NEBRASKA AND WILL PROBABLY
AFFECT VTN...ANW...ONL AND BBW AFTER 06Z SATURDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
235 PM EDT FRI SEP 13 2013
.SYNOPSIS...
MOSTLY CLOUDY SKIES WILL PERSIST TONIGHT...WITH SCATTERED LIGHT SHOWERS
AND PATCHY DRIZZLE MAINLY DOWNWIND OF LAKE ONTARIO AND THE FINGER
LAKES. SKIES WILL BECOME PARTLY TO MOSTLY SUNNY ON SATURDAY AS
HIGH PRESSURE BUILDS IN FROM THE GREAT LAKES. FAIR AND WARMER
WEATHER IS EXPECTED ON SUNDAY AS THIS HIGH MOVES OFF THE EAST
COAST. A COLD FRONT WILL PASS THE REGION ON SUNDAY NIGHT AND
MONDAY WITH A CHANCE OF SHOWERS.
&&
.NEAR TERM /THROUGH SATURDAY/...
BATCH OF HEAVIER SHRA ACRS SE ZONES WILL MOVG OUT OF THE AREA BY
MID/LATE AFTN AS UPR LOW CONTINUES IT`S SLOW NEWD TREK. ANOTHER
VORT AXIS ACRS MI WILL MOV EWD ACRS THE FCST AREA LATER TNGT.
PLENTY OF LOW LVL MSTR PERSISTS TNGT...AND CONDITIONAL LAKE
INSTABILITY DVLPS. LOW LVL FLOW WILL MEANDER ARND 340 DEG...WITH
LAKE ONTARIO AND THE FINGER LAKES LIKELY AIDING DVLPMNT OF --SHRA
OR PATCHY -DZ. BEST BEST FOR LGT PCPN APPEARS TO BE ALONG AND W OF
THE I-81 CORRIFOR. GIVEN EXPECTATION OF CLDS TNGT XPCT MOST LOWS
TO BE IN THE M40S.
NAM/GFS STRONGLY SUGGEST THAT WE`LL BE CLEARING OUT EARLY TMRW
MRNG...BUT GEM HOLDS ONTO THE CLDS MUCH LONGER (WELL INTO THE
AFTN...SPCLY ERN ZONES). LATEST RUC PROFILES ALSO SUGGEST OVC
SKIES AT 11Z ACRS CNTRL NY. FOR THIS REASON WE WERE LEARLY OF
CLEARING OUT THE SKIES AS QUICK AS MOS WOULD SUGGEST. CRNT FCST
MAY STILL BE TOO QUICK IN CLEARING THINGS OUT BUT TRENDED TWDS
SLOWER IMPPRVMNT TMRW. MAXES TMRW ON THE COOL SIDE...GNRLY 60-65.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
SFC HI PRES RDG CRESTS OVER THE FCST AREA ON SAT NGT. POTNL FOR
PATCHY FROST SPCLY IN THE CATSKILLS AND COLDER SRN TIER VLYS. FOR
NOW WILL JUST MENTION POTNL IN THE HWO. OTRW SUNDAY LOOKS LIKE A
NICE DAY WITH MAXES MODERATING INTO THE U60S AND LOWER 70S. WE`LL
PRBLY SEE A BKN CI DEWK MOVG INTO THE REGION DURING THE AFTN
AHEAD OF THE NXT S/WV. THIS WAVE WILL PUSH A CDFNT THRU ON SUNDAY
NGT...WITH POTNL FOR 2NDRY REINFORCING SHOT ON MONDAY. CHC/LIKELY
POPS FOR SUNDAY NGT...DCRSNG TO CHC POPS ON MONDAY. BEST CHC FOR
-SHRA ON MON APPEARS TO BE IN THE MRNG...WITH DRIER AIR AND
IMPRVNG SKY COVER ACRS NRN ZONES ON MON AFTN.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AT THE BEGINNING OF THE PERIOD UPPER LEVEL TROF WILL MOVE EAST OF
AREA AS A FLAT RIDGE BUILDS ACROSS THE NORTHEAST. LATE IN THE
PERIOD AN UPPER LEVEL TROF DROPS INTO THE GREAT LAKES.
WILL CONTINUE WITH A DRY FORECAST MONDAY NIGHT THROUGH WEDNESDAY,
AS SFC HIGH PRES BUILDS SOUTH ACROSS THE AREA ON TUESDAY THEN
MOVES OFF THE NEW JERSEY COAST BY WEDNESDAY. TEMPS WILL WARM
DURING THE PERIOD AS FLOW SHIFTS FROM NORTHWEST TO SOUTHWEST.
WEDNESDAY NIGHT THROUGH FRIDAY, WILL CARRY SLIGHT CHC/CHC POPS AS
NEXT UPPER LEVEL TROF APPROACHES THE REGION AND ASSOCIATED SFC LOW
TRACKS FROM THE UPPER GREAT LAKES EAST ACROSS NEARBY SOUTHERN
CANADA. MEDIUM RANGE MODELS SHOW SIGNIFICANT TIMING DIFFERENCES
WITH THIS FEATURE, WITH THE ECMWF FASTER THAN THE GFS. AREA MAY
BE IMPACTED BY WARM FRONTAL SHOWERS THURSDAY/THURSDAY NIGHT
FOLLOWED BY SFC COLD FRONT ON FRIDAY. TEMPS WILL RANGE SLIGHTLY
ABOVE NORMAL.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
UPPER LEVEL TROF WILL REMAIN OVER THE AREA THROUGH THIS TAF PERIOD
WITH A COOL NORTHWEST FLOW. THROUGH MID MORNING SATURDAY
WIDESPREAD MVFR/LOW MVFR CIGS ARE EXPECTED WITH IFR CIGS LIKELY AT
KBGM/KITH LATE TONIGHT. SCATTERED LIGHT LAKE EFFECT RAIN SHOWERS
ARE ALSO EXPECTED OVERNIGHT MAINLY IN THE FINGER LAKES REGION.
THIS WAS INCLUDED IN JUST THE KITH TERMINAL. SATURDAY, LOW LEVEL
DRYING WILL LEAD TO VFR CONDITIONS BY MIDDAY.
NORTHWEST WINDS AROUND 10 KNOTS WITH GUSTS 15-20 KNOTS THIS AFTERNOON.
OUTLOOK...
SUN...VFR...BUT MAYBE SOME EARLY MORNING FOG/IFR AT KELM.
SUN NGT/MON...RESTRICTIONS IN SCATTERED SHOWERS.
MON NGT THROUGH WED...VFR UNDER HIGH PRESSURE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1032 AM EDT FRI SEP 13 2013
.SYNOPSIS...
MUCH COOLER AIR FOLLOWING THE PASSAGE OF A COLD FRONT WILL DROP
TEMPERATURES WELL BELOW SEASONAL AVERAGES FOR THE NEXT COUPLE OF
DAYS. THE COLDER AIR WILL PRODUCE LAKE EFFECT CLOUDS ACROSS MUCH OF
THE REGION...WITH SCATTERED LAKE EFFECT SHOWERS TODAY INTO PART OF
TONIGHT. HIGH PRESSURE BUILDING ACROSS NEW YORK STATE WILL THEN
BRING MOSTLY SUNNY SKIES THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LONGWAVE TROUGH IS CENTERED OVER QUEBEC/NY THIS MORNING WITH AN
EMBEDDED SHORTWAVE TROUGH OVER CENTRAL NY. RUC ANALYSIS SHOWS THE
COLD AIR AT 500MB WITH THIS FEATURE NEARLY OVERHEAD. WIDESPREAD
CLOUD COVER WILL CONTINUE UNDER THIS REGIME WITH GENERALLY NORTHERLY
FLOW ALOFT. AS FAR A RAIN SHOWERS GO...WARMING ALOFT AT 500MB WILL
NEGATE LOWER LEVEL INSTABILITY OVER FAR WESTERN NY. THERE IS ALSO
SOME DIRECTIONAL SHEAR IN THE LOW LEVEL AIRMASS. SO WHILE SOME
SHOWERS ARE POSSIBLE...DO NOT EXPECT ANYTHING LONG LIVED SHOWER
ACTIVITY...WITH TRACE TO A FEW HUNDREDTHS OVER THE COURSE OF THE
DAY.
TOWARD THE EASTERN LAKE ONTARIO...A DIFFERENT SCENARIO MAY RESULT AS
THE SHORTWAVE TROUGH SLOWLY MOVES NE WITH COOLING ALOFT AT ALL
LEVELS. RADAR RETURNS ARE MOSTLY QUIET NOW WITH WEBCAMS SHOWING
MOSTLY LIGHT SPRINKLES. WITH AFTERNOON MIXING...EXPECT SOME
CELLULAR SHOWER ACTIVITY TO DEVELOP.
IN TERMS OF TEMPERATURES...CLOUD COVER AND ONGOING COLD AIR
ADVECTION WILL KEEP TEMPERATURES IN THE 50S TODAY...WHICH IS ALMOST
20 DEGREES BELOW AVERAGE...A DRAMATIC CHANGE COMPARED TO THE MID
SUMMER-LIKE HEAT THAT WE SAW EARLIER IN THE WEEK.
TONIGHT...SCATTERED RAIN SHOWERS SHOULD DIMINISH WITH THE LOSS OF
DAYLIGHT INDUCED MIXING...ALTHOUGH A LINGERING RESPONSE FROM LAKE
ONTARIO MAY LAST THROUGH THE FIRST HALF OF THE NIGHT.
OTHERWISE...EXPECT MOSTLY CLOUDY SKIES TO PREVAIL AS THE NORTHWEST
UPSLOPE FLOW REMAINS INTACT. THE CLOUD COVER WILL LIKELY PRECLUDE
THE DEVELOPMENT OF FROST ACROSS THE SOUTHERN TIER WHERE TEMPERATURES
MAY DIP INTO THE UPPER 30S BEFORE DAYBREAK. THE REST OF THE AREA
WILL SEE TEMPERATURES COOLING INTO THE LOWER AND MID 40S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ON SATURDAY A DEEP MID LEVEL TROUGH WILL DRIFT EAST ACROSS NEW
ENGLAND WITH ITS INFLUENCE ON OUR REGION DIMINISHING AS SURFACE HIGH
PRESSURE BUILDS INTO THE LOWER LAKES. LINGERING NORTHERLY FLOW ALOFT
MAY KEEP A FEW CLOUDS DURING THE MORNING ESPECIALLY SOUTHEAST OF
LAKE ONTARIO AND ACROSS HIGHER TERRAIN...BUT THESE SHOULD YIELD TO
INCREASING SUNSHINE DURING THE DAY AS SUBSIDENCE AND DRYING BEGIN TO
DOMINATE. 850MB TEMPS RECOVER TO AROUND +5C BY AFTERNOON WHICH WILL
SUPPORT HIGHS IN THE MID 60S AT LOWER ELEVATIONS AND AROUND 60
ACROSS HIGHER TERRAIN...STILL ABOUT 5-8 DEGREES BELOW AVERAGE.
SATURDAY NIGHT SURFACE HIGH PRESSURE WILL DRIFT FROM THE LOWER LAKES
TO THE MID ATLANTIC STATES. THIS WILL BRING CLEAR SKIES AND LIGHT
WINDS TO THE REGION SETTING THE STAGE FOR A GOOD RADIATIONAL COOLING
NIGHT. EVEN THOUGH TEMPERATURES ALOFT WILL BE MODERATING...STRONG
DIURNAL COOLING WILL SUPPORT LOWS IN THE 40S ON THE LAKE PLAINS WITH
SOME 30S ACROSS THE INTERIOR SOUTHERN TIER AND WELL EAST OF LAKE
ONTARIO. SOME OF THE COOLEST VALLEYS OF THE SOUTHERN TIER AND THE
TUG HILL REGION MAY SEE JUST A LITTLE PATCHY LIGHT FROST. THE STRONG
COOLING WILL ALSO SUPPORT TYPICAL RIVER VALLEY FOG ACROSS THE
SOUTHERN TIER.
ON SUNDAY SOUTHWEST RETURN FLOW WILL DEVELOP BETWEEN THE DEPARTING
HIGH AND THE NEXT APPROACHING COLD FRONT. THIS WILL BRING
TEMPERATURES BACK TO VERY NEAR AVERAGE WITH LOWER 70S AT LOWER
ELEVATIONS AND MID TO UPPER 60S ACROSS HIGHER TERRAIN. INCREASING
UPPER LEVEL DIVERGENCE AND SOME LEAD MID LEVEL SHORTWAVE ENERGY WILL
BRING AN INCREASE IN CIRRUS LEVEL CLOUDINESS DURING THE DAY WITH
MORNING SUNSHINE FADING BEHIND INCREASING HIGH CLOUDS.
SUNDAY NIGHT AND EARLY MONDAY A RE-ENFORCING TROUGH WILL DIG INTO
QUEBEC AND FORCE ANOTHER SEASONABLY STRONG COLD FRONT ACROSS THE
REGION. UPPER LEVEL SUPPORT IS QUITE STRONG WITH A WELL DEFINED
SHORTWAVE DIGGING THROUGH THE BASE OF THE TROUGH AND PROVIDING LARGE
SCALE ASCENT AS DPVA SPREADS INTO THE LOWER LAKES LATER SUNDAY
NIGHT. A 100+ KNOT UPPER LEVEL JET OVER QUEBEC WILL ALSO BE IN A
POSITION TO PLACE THE LOWER LAKES IN THE FAVORABLE RIGHT ENTRANCE
REGION...BRINGING A PERIOD OF ORGANIZED UPPER LEVEL DIVERGENCE. THE
FRONT WILL NOT BE MOISTURE RICH BY ANY MEANS...BUT WILL HAVE A PLUME
OF PWAT AROUND 1 INCH TO WORK WITH. GIVEN THE STRONG DYNAMICS
SUPPORTING THE LOW LEVEL FRONTAL BOUNDARY...HAVE INCREASED POPS INTO
THE HIGH CHANCE RANGE FOR LATER SUNDAY NIGHT.
MONDAY MORNING THE FRONT WILL EXIT THE AREA TO THE SOUTHEAST WITH
ANY LINGERING SHOWERS TAPERING OFF FROM NORTHWEST TO SOUTHEAST. THE
AIRMASS BECOMES COLD ENOUGH FOR SOME LAKE ENHANCEMENT JUST BEHIND
THE FRONT...AND THIS MAY CAUSE SHOWERS TO LINGER FOR A FEW EXTRA
HOURS MAINLY SOUTHEAST OF LAKE ONTARIO FROM ROCHESTER TO OSWEGO
COUNTY. LATER MONDAY THE AIRMASS QUICKLY DRIES AS STRONG HIGH
PRESSURE BUILDS INTO THE CENTRAL LAKES WITH INCREASING SUBSIDENCE
BRINGING A RAPID END TO ANY LAKE EFFECT SHOWERS THAT DO FORM. THIS
SHOULD ALSO BRING AT LEAST SOME LIMITED SUNSHINE DURING THE
AFTERNOON...ALTHOUGH WITH CHILLY NORTHWEST FLOW ALOFT CLOUDS MAY
CLEAR SLOWER THAN MODEL GUIDANCE CURRENTLY INDICATES. 850MB TEMPS
FALL TO AROUND +4C...AND THIS WILL BRING HIGHS BACK DOWN TO AROUND
60 AT LOWER ELEVATIONS AND MID TO UPPER 50S ACROSS HIGHER TERRAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE ROLLER COASTER RIDE OF TEMPERATURES WILL CONTINUE THROUGH THE
LONG TERM AS THE PATTERN ACROSS NORTH AMERICA REMAINS PROGRESSIVE
WITH PERIODS OF MODERATE AMPLIFICATION SEPARATED BY BRIEF PERIODS OF
ZONAL FLOW. AROUND THE MIDDLE OF NEXT WEEK THE PATTERN WILL BECOME
ZONAL...WHICH WILL ALLOW HEIGHT RISES AND WARMER TEMPERATURES TO
SPREAD EAST INTO THE OHIO VALLEY AND GREAT LAKES.
LOOKING AT THE DETAILS...MONDAY NIGHT HIGH PRESSURE WILL BUILD INTO
THE LOWER LAKES AND COMBINE WITH A COOL AIRMASS TO BRING ANOTHER
CHILLY NIGHT. IF CURRENT MODEL TEMPERATURE GUIDANCE IS CLOSE WE MAY
HAVE SOME MORE FROST IN THE COOLER SOUTHERN TIER VALLEYS AND WELL
EAST OF LAKE ONTARIO.
HIGH PRESSURE DRIFTS TO THE EAST COAST TUESDAY THROUGH WEDNESDAY
WITH TEMPERATURES MODERATING SOME ON TUESDAY...THEN TO AT OR ABOVE
AVERAGE BY WEDNESDAY AS RETURN FLOW INCREASES. FURTHER WARMING WILL
MOVE IN BY THURSDAY...BUT THIS WILL BE ACCOMPANIED BY INCREASING
RAIN CHANCES AS WARM ADVECTION AND DEEPER MOISTURE SPREAD INTO THE
REGION.
LOOKING FURTHER AHEAD...BIG DISCREPANCIES IN MODEL GUIDANCE BY NEXT
FRIDAY INTO THE FOLLOWING WEEKEND. THE NEW 00Z ECMWF DIGS ANOTHER
SHARP TROUGH INTO THE NORTHEAST WITH A FRESH SHOT OF COOL AIR...
WHILE THE 00Z GFS REMAINS MORE ZONAL WITH MILD TEMPERATURES. THE
MAJORITY OF 00Z GEFS ENSEMBLE MEMBERS SUPPORT THE OPERATIONAL GFS
SOLUTION...WITH ONLY A FEW SUGGESTING A DEEPER EASTERN TROUGH. THE
RECENT TREND HAS BEEN FOR TROUGH AMPLIFICATION IN THE NORTHEAST...
SO TIME WILL TELL IF THE ECMWF IS THE FIRST TO CAPTURE THE NEXT
TROUGH AMPLIFICATION...OR IF THIS RUN IS JUST AN INCORRECT OUTLIER.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
A NORTHWEST FLOW OF COLDER AIR WILL CONTINUE TO MOVE ACROSS THE AREA
TODAY. THE COLDER AIR AND LINGERING LOW LEVEL MOISTURE BEHIND THE
DEPARTED COLD FRONT WILL CAUSE WIDESPREAD MVFR CIGS DUE TO UPSLOPE
FLOW. A SLOW IMPROVEMENT IS CIGS IS EXPECTED WITH TIME.
OUTLOOK...
SATURDAY THROUGH TUESDAY...VFR.
&&
.MARINE...
SMALL CRAFT ADVISORIES REMAIN IN PLACE ALONG THE SOUTHERN SHORES OF
LAKE ONTARIO AND HAVE BEEN EXTENDED TO THE EASTERN SHORES OF LAKE
ERIE...FROM DUNKIRK TO RIPELY. THESE CONDITIONS WILL LAST THROUGH
TONIGHT...ESPECIALLY ON LAKE ONTARIO WHERE THE NORTHWEST FLOW OF
UNSEASONABLY COOL AIR WILL ALLOW HIGHER WIND GUSTS TO MIX DOWN TO
THE LAKE SURFACE.
WIND AND WAVES WILL SUBSIDE A BIT ON SATURDAY AS HIGH PRESSURE
BUILDS EAST ACROSS THE LOWER LAKES.
CONDITIONS OVER THE LAKES WILL ALSO BE FAVORABLE FOR THE DEVELOPMENT
OF WATERSPOUTS THIS MORNING INTO THE EARLY AFTERNOON.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT SATURDAY FOR LEZ040.
SMALL CRAFT ADVISORY UNTIL 5 AM EDT SATURDAY FOR
LOZ042>044.
&&
$$
SYNOPSIS...TJP
NEAR TERM...TJP/ZAFF
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...TJP/ZAFF
MARINE...TJP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
653 AM EDT FRI SEP 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA TODAY. CANADIAN HIGH PRESSURE
WILL BRING COOLER CONDITIONS FOR THE WEEKEND. A SECOND CANADIAN HIGH
WILL DROP SOUTHEAST INTO THE REGION EARLY NEXT WEEK...BRINGING A
REINFORCEMENT OF DRY AND MILD AIR FOR MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...THE RADAR REMAINS CLEAR ACROSS MY FORECAST
AREA WITH THE ONLY SHOWER ACTIVITY SHOWING UP WELL EAST AND
NORTHEAST OF WILMINGTON. I AM DROPPING POPS TO 10 PERCENT INLAND FOR
THE REMAINDER OF THE DAY...BUT WILL MAINTAIN THE 20-30 PERCENT
CHANCE OF MID-LATE DAY CONVECTION ALONG & EAST OF THE SEABREEZE. THE
LATEST HRRR RUN SHOWS A NARROW STRIP OF INCREASED DEWPOINTS AND
SURFACE-BASED CAPE VALUES DEVELOPING IN THE 18-22Z TIME FRAME AS THE
HUMID MARINE AIRMASS MOVES ONSHORE. NO SIGNIFICANT CHANGES ARE
NEEDED TO OTHER FORECAST ELEMENTS. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
THE UPPER AIR PATTERN HAS A RIDGE ACROSS THE CENTRAL ROCKIES WITH A
DEEP TROUGH ALONG THE EAST COAST. A SHORTWAVE DISTURBANCE DIPPING
INTO THE EAST COAST TROUGH WILL HELP PUSH A COLD FRONT INTO THE
EASTERN CAROLINAS TODAY. FAIRLY DRY CONDITIONS ALOFT...MARGINAL
MID-LEVEL LAPSE RATES...AND UNFAVORABLE JET DYNAMICS SHOULD HELP
KEEP MOST AREAS DRY. THERE IS A SLIGHT CHANCE OF A SHOWER OR T-STORM
INLAND THIS MORNING AS A PREFRONTAL TROUGH AND THE ACTUAL COLD FRONT
ARRIVE. POTENTIAL FOR SHOWERS OR T-STORMS THEN SHIFTS TO THE COAST
BY MID-TO-LATE AFTERNOON AS THE FRONT COLLIDES WITH THE SEABREEZE
BOUNDARY. THE SEABREEZE SHOULD THROW BETTER BOUNDARY LAYER MOISTURE
INLAND FOR THE SUN TO WORK ON... GENERATING A NARROW ZONE OF CAPE AS
HIGH AS 1500 J/KG. FORECAST POPS ARE NO HIGHER THAN ABOUT 30%
ANYWHERE TODAY.
THERE IS A FAIRLY LARGE DIFFERENCE IN FORECAST HIGHS TODAY BETWEEN
THE WARM GFS AND THE COOLER NAM/ECMWF. IN SIMILAR SITUATIONS EARLIER
IN THE SUMMER THE GFS HAS BEEN THE CLEAR WINNER...AND THIS APPEARS
TO BE THE WAY TO GO TODAY...PARTICULARLY GIVEN THE WARM START WE
WILL HAVE AT SUNRISE. THIS MEANS HIGHS SHOULD REACH 90 INLAND...WITH
MID TO UPPER 80S AT THE COAST.
COOLER AND DRIER AIR WILL PUSH IN BEHIND THE FRONT TONIGHT AS WINDS
SHIFT TO THE NORTH. WHILE I WOULD LIKE TO FORECAST CLEARING SKIES...
IT APPEARS A LAYER OF MOISTURE WILL BECOME TRAPPED ABOVE THE FRONTAL
SURFACE AND BELOW THE BUILDING SUBSIDENCE INVERSION ALOFT. THIS
COULD LEAD TO...IF THE 00Z NAM IS RIGHT...NEARLY OVERCAST CONDITIONS
WITH WARMER OVERNIGHT TEMPERATURES DUE TO LACK OF RADIATIONAL
COOLING. THE GFS HAS DRIER AIR IN THE 900-700 MB LAYER AND NOT
SURPRISINGLY IS FORECASTING MUCH LOWER TEMPERATURES TONIGHT. I HAVE
SPLIT THE DIFFERENCE WITH FORECAST LOWS...RANGING FROM THE LOWER 60S
FROM BURGAW THROUGH ELIZABETHTOWN...LUMBERTON AND BENNETTSVILLE...
TO THE MID 60S MOST ELSEWHERE. THE BEACHES WILL PROBABLY REMAIN IN
THE UPPER 60S FOR LOWS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...ESSENTIALLY A TEMPERATURE FORECAST AS A
PROGRESSIVE MID LEVEL TROUGH DOMINATES SATURDAY WITH A ZONAL FLOW
QUICKLY SETTING UP SUNDAY. AT THE SURFACE...HIGH PRESSURE WILL MOVE
FROM THE MIDWEST TO OFFSHORE WITH AN ELONGATED WEST/EAST AXIS
SUNDAY. WITH PRECIPITABLE WATER VALUES DOWN TO JUST OVER AN
INCH...POPS WILL NOT BE AN ISSUE. SOUNDINGS SHOW ENOUGH MOISTURE AND
STEEP LOW LEVEL LAPSE RATES FOR STRATOCUMULUS TO DEVELOP MIDDAY
SATURDAY AND SUNDAY BUT THAT IS ABOUT IT. TEMPERATURE GUIDANCE HAS
IMPROVED DRAMATICALLY WHEN COMPARED TO THIS TIME LAST NIGHT AND
THERE IS VERY LITTLE DIFFERENCE BETWEEN THE MET AND NAM NUMBERS. I
DID TWEAK UP SUNDAY MORNING LOWS TO MATCH THIS TREND AS IT ALWAYS
SEEMS A GOOD PLAY TO GO WARMER WITH THE BOUNDARY LAYER NOT
COMPLETELY
DECOUPLED...OTHERWISE NO CHANGES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...THE MID LEVEL PATTERN WILL TRANSITION FROM A
MODEST AND PROGRESSIVE EAST COAST TROUGH TO ONE MORE RESEMBLING MID
SUMMER FOR TUESDAY THROUGH THURSDAY. THIS IS MOSTLY A WEST TO EAST
FLOW. THE TROUGH WILL ALLOW A MODEST SECONDARY SURGE OF MOSTLY DRIER
AIR INTO THE AREA TUESDAY WHICH WILL BRIEFLY DROP TEMPERATURES AND
DEWPOINTS A COUPLE OF DEGREES. READINGS RECOVER QUICKLY WEDNESDAY
AND THURSDAY VIA MOSTLY AIR MASS MODIFICATION AS THE SURFACE HIGH
MOVES BASICALLY EASTWARD. REGARDING POPS...THE ONLY OPPORTUNITIES
AND THEY ARE SMALL ARE WITH THE SURGE TUESDAY AND SEA BREEZE
ACTIVITY WEDNESDAY AND THURSDAY. ALL VALUES ARE SLIGHT CHANCE AND
THIS IS PROBABLY BEING GENEROUS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...SATELLITE SHOWS BROKEN HIGH CLOUDS OVER THE REGION AHEAD
OF A COLD FRONT THAT WILL DROP THROUGH LATER TODAY. LITTLE TO NO
WEATHER ASSOCIATED WITH IT...AN ISOLATED SHOWER PERHAPS ALTHOUGH
THERE IS LITTLE MOISTURE ASSOCIATED WITH THE SYSTEM. WEST WINDS THIS
MORNING WILL SHIFT TO THE NORTH NORTHEAST BY LATE AFTERNOON TO EARLY
EVENING. BEHIND THE FRONT...TIME HEIGHT INDICATES A VFR STRATA CU
CEILING WILL SET UP TONIGHT WITH NORTHEAST WINDS REMAINING AROUND 10
KTS THROUGH THE NIGHTTIME HOURS. NO FOG IS EXPECTED DUE TO GOOD
MIXING.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
VERY SLIGHT CHANCE OF SHOWERS LATE MONDAY INTO EARLY TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...INCREASED FORECAST WINDS A COUPLE OF KNOTS TO
ACCOUNT FOR SOME 19-22 KNOT GUSTS BEING REPORTED AT FRYING PAN
SHOALS AND BALD HEAD ISLAND RESPECTIVELY. THE PERIOD OF STRONGEST
WINDS SHOULD BE OCCURRING NOW...WITH A RATHER RAPID DIMINISHING
TREND IN WIND SPEEDS DEVELOPING AFTER 10 A.M. SEAS HAVE BUILT TO 4
FT AT THE FRYING PAN SHOALS BUOY...WITH 3 FT REPORTED CLOSER TO
SHORE.
NO OTHER SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
A COLD FRONT CURRENTLY LOCATED IN THE NC AND VA MOUNTAINS WILL MOVE
SOUTHEASTWARD TODAY...REACHING THE COASTAL WATERS LATE THIS EVENING.
UNTIL THEN...THE PRESSURE GRADIENT HAS TIGHTENED UP EARLY THIS
MORNING IN ADVANCE OF A SURFACE TROUGH ACROSS EASTERN NORTH
CAROLINA. THE RESULT HAS BEEN WINDS AROUND 15 KNOTS WITH GUSTS
MEASURED AS HIGH AS 19 KNOTS AT THE FRYING PAN SHOALS BUOY. LOOK FOR
WINDS TO TURN MORE WESTERLY AND DIMINISH TO 10 KT OR LESS LATER THIS
MORNING BEHIND THE TROUGH. INLAND TEMPERATURES WILL AGAIN PUSH
TOWARD 90 DEGREES THIS AFTERNOON CREATING A SEABREEZE CIRCULATION
WITH NEARSHORE WINDS BACKING TO THE SOUTH. ONCE THE FRONT ARRIVES
LATE THIS EVENING WINDS WILL TURN NORTH- NORTHEAST AND INCREASE IN A
COOL SURGE AHEAD OF CANADIAN HIGH PRESSURE...REACHING 15-20 KT BY
SUNRISE SATURDAY.
SEAS CURRENTLY AROUND 3 FT SHOULD DIMINISH TO 2 FT THIS AFTERNOON.
HOWEVER SEAS WILL AGAIN BUILD WITH THE NE SURGE OVERNIGHT...REACHING
3-4 FT BY DAYBREAK.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A NORTHEASTERLY FLOW WILL PREVAIL THROUGH MOST
OF THE PERIOD. LATE SUNDAY WINDS WILL ACQUIRE A MORE EASTERLY
COMPONENT. MODEL GUIDANCE REMAINS CONSISTENT WITH REGARDS TO WIND
SPEEDS WITH A SOLID 15-20 KNOTS SATURDAY SLOWLY DIMINISHING SUNDAY.
SIGNIFICANT SEAS WILL SEE A RANGE OF 3-5 FEET SATURDAY FALLING DOWN
TO 2-4 FEET SUNDAY. A SCEC HEADLINE MAY BE NEEDED SATURDAY.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...EARLY NEXT WEEK IS SHAPING UP TO OFFER NICE
CONDITIONS FOR THE MARINE COMMUNITY...ESPECIALLY MONDAY. AS HIGH
PRESSURE WEAKENS AND MOVES OFFSHORE...NORTHEAST WINDS WILL TURN TO
MORE EASTERLY WITH SPEEDS TEN KNOTS OR BELOW. A SECONDARY BOUNDARY
WILL INCREASE SPEEDS A BIT TUESDAY AND TURN THE WINDS BACK TO
NORTHEAST...BUT STILL MANAGEABLE AT 10-15 KNOTS. WAVEWATCH SEAS ARE
NOW SHOWING A SUBTLE LONG PERIOD SWELL COMPONENT AT THE END OF THE
PERIOD...MOST LIKELY FROM GABRIELLE BUT IT SHOULD NOT IMPACT
SIGNIFICANT SEAS DRAMATICALLY. OVERALL 2-3 FEET SHOULD SUFFICE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
647 AM EDT FRI SEP 13 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA TODAY. CANADIAN HIGH PRESSURE
WILL BRING COOLER CONDITIONS FOR THE WEEKEND. A SECOND CANADIAN HIGH
WILL DROP SOUTHEAST INTO THE REGION EARLY NEXT WEEK...BRINGING A
REINFORCEMENT OF DRY AND MILD AIR FOR MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...THE RADAR REMAINS CLEAR ACROSS MY FORECAST
AREA WITH THE ONLY SHOWER ACTIVITY SHOWING UP WELL EAST AND
NORTHEAST OF WILMINGTON. I AM DROPPING POPS TO 10 PERCENT INLAND FOR
THE REMAINDER OF THE DAY...BUT WILL MAINTAIN THE 20-30 PERCENT
CHANCE OF MID-LATE DAY CONVECTION ALONG & EAST OF THE SEABREEZE. THE
LATEST HRRR RUN SHOWS A NARROW STRIP OF INCREASED DEWPOINTS AND
SURFACE-BASED CAPE VALUES DEVELOPING IN THE 18-22Z TIME FRAME AS THE
HUMID MARINE AIRMASS MOVES ONSHORE. NO SIGNIFICANT CHANGES ARE
NEEDED TO OTHER FORECAST ELEMENTS. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
THE UPPER AIR PATTERN HAS A RIDGE ACROSS THE CENTRAL ROCKIES WITH A
DEEP TROUGH ALONG THE EAST COAST. A SHORTWAVE DISTURBANCE DIPPING
INTO THE EAST COAST TROUGH WILL HELP PUSH A COLD FRONT INTO THE
EASTERN CAROLINAS TODAY. FAIRLY DRY CONDITIONS ALOFT...MARGINAL
MID-LEVEL LAPSE RATES...AND UNFAVORABLE JET DYNAMICS SHOULD HELP
KEEP MOST AREAS DRY. THERE IS A SLIGHT CHANCE OF A SHOWER OR T-STORM
INLAND THIS MORNING AS A PREFRONTAL TROUGH AND THE ACTUAL COLD FRONT
ARRIVE. POTENTIAL FOR SHOWERS OR T-STORMS THEN SHIFTS TO THE COAST
BY MID-TO-LATE AFTERNOON AS THE FRONT COLLIDES WITH THE SEABREEZE
BOUNDARY. THE SEABREEZE SHOULD THROW BETTER BOUNDARY LAYER MOISTURE
INLAND FOR THE SUN TO WORK ON... GENERATING A NARROW ZONE OF CAPE AS
HIGH AS 1500 J/KG. FORECAST POPS ARE NO HIGHER THAN ABOUT 30%
ANYWHERE TODAY.
THERE IS A FAIRLY LARGE DIFFERENCE IN FORECAST HIGHS TODAY BETWEEN
THE WARM GFS AND THE COOLER NAM/ECMWF. IN SIMILAR SITUATIONS EARLIER
IN THE SUMMER THE GFS HAS BEEN THE CLEAR WINNER...AND THIS APPEARS
TO BE THE WAY TO GO TODAY...PARTICULARLY GIVEN THE WARM START WE
WILL HAVE AT SUNRISE. THIS MEANS HIGHS SHOULD REACH 90 INLAND...WITH
MID TO UPPER 80S AT THE COAST.
COOLER AND DRIER AIR WILL PUSH IN BEHIND THE FRONT TONIGHT AS WINDS
SHIFT TO THE NORTH. WHILE I WOULD LIKE TO FORECAST CLEARING SKIES...
IT APPEARS A LAYER OF MOISTURE WILL BECOME TRAPPED ABOVE THE FRONTAL
SURFACE AND BELOW THE BUILDING SUBSIDENCE INVERSION ALOFT. THIS
COULD LEAD TO...IF THE 00Z NAM IS RIGHT...NEARLY OVERCAST CONDITIONS
WITH WARMER OVERNIGHT TEMPERATURES DUE TO LACK OF RADIATIONAL
COOLING. THE GFS HAS DRIER AIR IN THE 900-700 MB LAYER AND NOT
SURPRISINGLY IS FORECASTING MUCH LOWER TEMPERATURES TONIGHT. I HAVE
SPLIT THE DIFFERENCE WITH FORECAST LOWS...RANGING FROM THE LOWER 60S
FROM BURGAW THROUGH ELIZABETHTOWN...LUMBERTON AND BENNETTSVILLE...
TO THE MID 60S MOST ELSEWHERE. THE BEACHES WILL PROBABLY REMAIN IN
THE UPPER 60S FOR LOWS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...ESSENTIALLY A TEMPERATURE FORECAST AS A
PROGRESSIVE MID LEVEL TROUGH DOMINATES SATURDAY WITH A ZONAL FLOW
QUICKLY SETTING UP SUNDAY. AT THE SURFACE...HIGH PRESSURE WILL MOVE
FROM THE MIDWEST TO OFFSHORE WITH AN ELONGATED WEST/EAST AXIS
SUNDAY. WITH PRECIPITABLE WATER VALUES DOWN TO JUST OVER AN
INCH...POPS WILL NOT BE AN ISSUE. SOUNDINGS SHOW ENOUGH MOISTURE AND
STEEP LOW LEVEL LAPSE RATES FOR STRATOCUMULUS TO DEVELOP MIDDAY
SATURDAY AND SUNDAY BUT THAT IS ABOUT IT. TEMPERATURE GUIDANCE HAS
IMPROVED DRAMATICALLY WHEN COMPARED TO THIS TIME LAST NIGHT AND
THERE IS VERY LITTLE DIFFERENCE BETWEEN THE MET AND NAM NUMBERS. I
DID TWEAK UP SUNDAY MORNING LOWS TO MATCH THIS TREND AS IT ALWAYS
SEEMS A GOOD PLAY TO GO WARMER WITH THE BOUNDARY LAYER NOT
COMPLETELY
DECOUPLED...OTHERWISE NO CHANGES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...THE MID LEVEL PATTERN WILL TRANSITION FROM A
MODEST AND PROGRESSIVE EAST COAST TROUGH TO ONE MORE RESEMBLING MID
SUMMER FOR TUESDAY THROUGH THURSDAY. THIS IS MOSTLY A WEST TO EAST
FLOW. THE TROUGH WILL ALLOW A MODEST SECONDARY SURGE OF MOSTLY DRIER
AIR INTO THE AREA TUESDAY WHICH WILL BRIEFLY DROP TEMPERATURES AND
DEWPOINTS A COUPLE OF DEGREES. READINGS RECOVER QUICKLY WEDNESDAY
AND THURSDAY VIA MOSTLY AIR MASS MODIFICATION AS THE SURFACE HIGH
MOVES BASICALLY EASTWARD. REGARDING POPS...THE ONLY OPPORTUNITIES
AND THEY ARE SMALL ARE WITH THE SURGE TUESDAY AND SEA BREEZE
ACTIVITY WEDNESDAY AND THURSDAY. ALL VALUES ARE SLIGHT CHANCE AND
THIS IS PROBABLY BEING GENEROUS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A COLD FRONT OVER THE WESTERN CAROLINAS WILL CONTINUE
APPROACHING THE AREA THIS MORNING. SURFACE WINDS 4-8 KTS WILL KEEP
THE BOUNDARY LAYER MIXED...SO DO NOT ANTICIPATE ANY FOG ISSUES. HAVE
INCLUDED VCSH THIS MORNING AS HI-RES GUIDANCE STILL SHOWS SOME
ISOLATED SHRA DEVELOPING AS THE FRONT APPROACHES. BY MIDDAY THE
FRONT SHOULD PUSH THROUGH OUR AREA...AND THE WINDS WILL VEER TO THE
NORTH OR NORTHWEST. THE GFS AND NAM CONTINUE TO HINT AT SOME
SHOWERS/T-STORMS ALONG THE COAST DURING THE AFTN HOURS...AS SFC
CONVERGENCE ALONG THE SEA BREEZE PROMOTES SHOWER DEVELOPMENT. DEEP
CONVECTION WILL BE TOUGH GIVEN THE DRIER AIR ALOFT AND THE MID-LEVEL
INVERSION...BUT HAVE ADDED VCSH FOR THE AFTN AT KILM/KCRE/KMYR AS
SHOWERS CANNOT BE RULED OUT. AFTER 21Z...PCPN ACTIVITY WILL REMAIN
OFFSHORE AND THE SKIES SHOULD BEGIN CLEARING OUT.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
VERY SLIGHT CHANCE OF SHOWERS LATE MONDAY INTO EARLY TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...INCREASED FORECAST WINDS A COUPLE OF KNOTS TO
ACCOUNT FOR SOME 19-22 KNOT GUSTS BEING REPORTED AT FRYING PAN
SHOALS AND BALD HEAD ISLAND RESPECTIVELY. THE PERIOD OF STRONGEST
WINDS SHOULD BE OCCURRING NOW...WITH A RATHER RAPID DIMINISHING
TREND IN WIND SPEEDS DEVELOPING AFTER 10 A.M. SEAS HAVE BUILT TO 4
FT AT THE FRYING PAN SHOALS BUOY...WITH 3 FT REPORTED CLOSER TO
SHORE.
NO OTHER SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
A COLD FRONT CURRENTLY LOCATED IN THE NC AND VA MOUNTAINS WILL MOVE
SOUTHEASTWARD TODAY...REACHING THE COASTAL WATERS LATE THIS EVENING.
UNTIL THEN...THE PRESSURE GRADIENT HAS TIGHTENED UP EARLY THIS
MORNING IN ADVANCE OF A SURFACE TROUGH ACROSS EASTERN NORTH
CAROLINA. THE RESULT HAS BEEN WINDS AROUND 15 KNOTS WITH GUSTS
MEASURED AS HIGH AS 19 KNOTS AT THE FRYING PAN SHOALS BUOY. LOOK FOR
WINDS TO TURN MORE WESTERLY AND DIMINISH TO 10 KT OR LESS LATER THIS
MORNING BEHIND THE TROUGH. INLAND TEMPERATURES WILL AGAIN PUSH
TOWARD 90 DEGREES THIS AFTERNOON CREATING A SEABREEZE CIRCULATION
WITH NEARSHORE WINDS BACKING TO THE SOUTH. ONCE THE FRONT ARRIVES
LATE THIS EVENING WINDS WILL TURN NORTH- NORTHEAST AND INCREASE IN A
COOL SURGE AHEAD OF CANADIAN HIGH PRESSURE...REACHING 15-20 KT BY
SUNRISE SATURDAY.
SEAS CURRENTLY AROUND 3 FT SHOULD DIMINISH TO 2 FT THIS AFTERNOON.
HOWEVER SEAS WILL AGAIN BUILD WITH THE NE SURGE OVERNIGHT...REACHING
3-4 FT BY DAYBREAK.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A NORTHEASTERLY FLOW WILL PREVAIL THROUGH MOST
OF THE PERIOD. LATE SUNDAY WINDS WILL ACQUIRE A MORE EASTERLY
COMPONENT. MODEL GUIDANCE REMAINS CONSISTENT WITH REGARDS TO WIND
SPEEDS WITH A SOLID 15-20 KNOTS SATURDAY SLOWLY DIMINISHING SUNDAY.
SIGNIFICANT SEAS WILL SEE A RANGE OF 3-5 FEET SATURDAY FALLING DOWN
TO 2-4 FEET SUNDAY. A SCEC HEADLINE MAY BE NEEDED SATURDAY.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...EARLY NEXT WEEK IS SHAPING UP TO OFFER NICE
CONDITIONS FOR THE MARINE COMMUNITY...ESPECIALLY MONDAY. AS HIGH
PRESSURE WEAKENS AND MOVES OFFSHORE...NORTHEAST WINDS WILL TURN TO
MORE EASTERLY WITH SPEEDS TEN KNOTS OR BELOW. A SECONDARY BOUNDARY
WILL INCREASE SPEEDS A BIT TUESDAY AND TURN THE WINDS BACK TO
NORTHEAST...BUT STILL MANAGEABLE AT 10-15 KNOTS. WAVEWATCH SEAS ARE
NOW SHOWING A SUBTLE LONG PERIOD SWELL COMPONENT AT THE END OF THE
PERIOD...MOST LIKELY FROM GABRIELLE BUT IT SHOULD NOT IMPACT
SIGNIFICANT SEAS DRAMATICALLY. OVERALL 2-3 FEET SHOULD SUFFICE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
115 AM EDT FRI SEP 13 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FRIDAY MORNING. CANADIAN HIGH
PRESSURE WILL BRING FALL-LIKE WEATHER THIS WEEKEND. A SECOND
CANADIAN HIGH WILL DROP SOUTHEAST INTO THE REGION EARLY NEXT
WEEK...BRINGING A REINFORCEMENT OF DRY AND MILD AIR FOR MUCH OF
THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 130 AM FRIDAY...RADAR SHOWS VIRTUALLY NO SHOWER ACTIVITY
ACROSS THE EASTERN CAROLINAS AT THIS TIME. LATEST FEW HRRR RUNS ARE
INCONSISTENT WITH THEIR PLACEMENT OF ANY SHOWERS BETWEEN NOW AND
SUNRISE LEADING TO VERY LOW CONFIDENCE THAT WE WILL HAVE
SHOWERS...AND IF SO WHERE. SLIGHT CHANCE (20 PERCENT) APPEARS TO BE
THE WAY TO GO. TEMPERATURES WILL REMAIN QUITE WARM FOR THE DATE
OVERNIGHT WITH THE PERSISTENT SOUTHWEST WIND. PREVIOUS DISCUSSION
FROM 1000 PM FOLLOWS...
TAIL END OF MID LEVEL SUBSIDENCE ACROSS THE FA THIS EVENING HAS KEPT
A TEMPORARY LID ON CONVECTIVE DEVELOPMENT. IE. NO TSRA/SHRA
DEVELOPMENT ALONG THE AFTERNOON/EVENING SEA BREEZE. THE SUBSIDENCE
LIES BETWEEN THE EXITING S/W TROF...WHAT WAS ONCE AN UPPER LOW OFF
THE SE U.S. COAST...OVER THE ADJACENT ATL WATERS AND THE APPROACHING
S/W TROF FROM THE WEST. FORCING/DYNAMICS FROM THIS UPPER S/W TROF
AND FORCING AHEAD OF THE APPROACHING SFC COLD FRONT...WILL BE ENOUGH
TO CONTINUE LOW CHANCE POPS ACROSS PORTIONS OF THE FA DURING THE
PRE-DAWN FRIDAY HOURS. LEFT OUT THUNDER FOR THE TIME BEING DUE TO
VERY LIMITED AVBL CAPE GIVEN THE TIME OF DAY. CURRENT MIN TEMP
FORECAST LOOKS AOK...WITH CONTINUED TWEAKING OF THE HOURLY SFC
DEWPOINTS BASED ON LATEST OBS/TRENDS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...DIGGING MID TO UPPER TROUGH EXTENDING DOWN
FROM THE GREAT LAKES WILL PUSH A COLD FRONT THROUGH THE AREA ON
FRIDAY. LATEST MODELS SHIFT THE BOUNDARY TO THE CAPE FEAR COAST
THROUGH FRI MORNING...BUT LOOKS LIKE WINDS WILL BACK AS SEA BREEZE
DEVELOPS. THIS WILL PRODUCE ENOUGH CONVERGENCE ALONG THE COAST
ALONG WITH ENOUGH LINGERING MOISTURE TO PRODUCE CLOUDS. WILL LEAVE
SOME CONVECTION POSSIBLE THROUGH EARLY AFTERNOON...BUT DRY COOL
AIR WILL PUSH IN BEHIND THE FRONT ADVECTING FROM NORTHWEST TO
SOUTHEAST AS WINDS SHIFT AROUND TO THE WEST-NORTHWEST BEHIND THE
FRONT. DEWPOINT TEMPS WILL DROP A GOOD 5 DEGREES THROUGH FRI
AFTERNOON. THIS COOL CANADIAN HIGH PRESSURE WILL BUILD INTO THE
AREA OVER THE WEEKEND PRODUCING UNSEASONABLY COOL AND DRY WEATHER.
THE MID TO UPPER TROUGH ACTUALLY BECOMES A BIT BROADER OVER THE
SOUTHEAST AS IT MOVES SLOWLY ACROSS TO NEW ENGLAND LATE FRI
THROUGH EARLY SAT. THIS WILL KEEP WINDS MORE WESTERLY IN THE MID TO
UPPER LEVELS THROUGH EARLY SATURDAY. A MORE SUBSTANTIAL PUSH OF
DEEP COOL AND DRY AIR WILL DEVELOP AS THIS H5 TROUGH CLEARS THE
COAST ON SATURDAY. EXPECT INLAND AREAS TO EXPERIENCE COOLER AND
DRIER CONDITIONS INITIALLY THROUGH LATE FRI BUT THIS SECONDARY
PUSH ON SAT WILL KEEP TEMPS BELOW 80 IN SPOTS ON SAT AND TEMPS
WILL DROP INTO THE LOWER 50S OVER PORTIONS OF CWA SAT NIGHT.
MOISTURE TRAPPED UNDER SUBSIDENCE INVERSION ON SATURDAY WILL
PRODUCE SOME CLOUDS...ESPECIALLY CLOSE TO THE COAST. THIS WILL
ALSO HELP TO LIMIT HEATING. THE COMBINATION OF CAA AND CLOUD
DEVELOPMENT WILL KEEP TEMPS A GOOD 5 TO 10 DEGREES COOLER THAN
PREVIOUS DAYS AND THE DRIER AIR WILL MAKE IT FEEL EVEN COOLER.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...WEAK RIDGING ALOFT AT THE START OF THE PERIOD
WILL SLOWLY BREAK DOWN NEXT WEEK. SURFACE HIGH OVERHEAD ON SUN WILL
YIELD TO A WEAK COLD FRONT MOVING IN FROM THE NORTH LATE MON OR
EARLY TUE. AHEAD OF THE FRONT LIGHT RETURN FLOW AND A BUMP IN LOW
LEVEL MOISTURE COULD PRODUCE ISOLATED SHOWERS MON AFTERNOON...MAINLY
NEAR THE COAST. WILL NOT CARRY A ZERO POP BUT WILL KEEP POP 10 OR
LESS. COOLER AND DRIER HIGH PRESSURE WILL BUILD IN FROM THE NORTH
BEHIND THE FRONT. LIMITED MOISTURE ALONG THE FRONT AND LACK OF
FORCING...INSTABILITY AND MID LEVEL SUPPORT SUGGESTS THE FRONT WILL
BE LITTLE MORE THAN A WIND SHIFT WITH LIMITED CLOUD COVER. HIGH
SLOWLY SHIFTS EAST NEXT WEEK...EVENTUALLY MOVING OFF THE MID
ATLANTIC COAST WED/THU. NORTHERLY FLOW TUE INTO WED WILL KEEP
TEMPERATURES NEAR TO SLIGHTLY BELOW CLIMO AND LIMIT PRECIP CHANCES.
DEVELOPING RETURN FLOW LATE NEXT WEEK LEADS TO A SLIGHT INCREASE IN
MOISTURE. LOW LEVEL MOISTURE IN CONCERT WITH WEAKENING MID LEVEL
SUBSIDENCE MAY ALLOW FOR DEVELOPMENT OF SOME DEEPER CONVECTION. FOR
NOW WILL MAINTAIN INHERITED SILENT POP WED/THU.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A COLD FRONT OVER THE WESTERN CAROLINAS WILL CONTINUE
APPROACHING THE AREA THIS MORNING. SURFACE WINDS 4-8 KTS WILL KEEP
THE BOUNDARY LAYER MIXED...SO DO NOT ANTICIPATE ANY FOG ISSUES. HAVE
INCLUDED VCSH THIS MORNING AS HI-RES GUIDANCE STILL SHOWS SOME
ISOLATED SHRA DEVELOPING AS THE FRONT APPROACHES. BY MIDDAY THE
FRONT SHOULD PUSH THROUGH OUR AREA...AND THE WINDS WILL VEER TO THE
NORTH OR NORTHWEST. THE GFS AND NAM CONTINUE TO HINT AT SOME
SHOWERS/T-STORMS ALONG THE COAST DURING THE AFTN HOURS...AS SFC
CONVERGENCE ALONG THE SEA BREEZE PROMOTES SHOWER DEVELOPMENT. DEEP
CONVECTION WILL BE TOUGH GIVEN THE DRIER AIR ALOFT AND THE MID-LEVEL
INVERSION...BUT HAVE ADDED VCSH FOR THE AFTN AT KILM/KCRE/KMYR AS
SHOWERS CANNOT BE RULED OUT. AFTER 21Z...PCPN ACTIVITY WILL REMAIN
OFFSHORE AND THE SKIES SHOULD BEGIN CLEARING OUT.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
VERY SLIGHT CHANCE OF SHOWERS LATE MONDAY INTO EARLY TUESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM FRIDAY...WINDS ARE A FEW KNOTS STRONGER THAN PREVIOUSLY
FORECAST BUT SEAS ARE RUNNING ABOUT 1 FOOT LESS AWAY FROM SHORE.
THIS ADDS UP TO SMALL CHANGES OVERALL. PREVIOUS DISCUSSION FROM 1000
PM FOLLOWS...
THE SFC PG HAS FINALLY BEGUN TO TIGHTEN ACROSS THE FA...AHEAD OF THE
APPROACHING COLD FRONT. THE LATEST OBS IE. OCPN7 AND
41013...INDICATE SW 10-15 KT WITH GUSTS UP TO 17 KT. THE LATEST HRRR
CONTINUES TO ILLUSTRATE SUSTAINED WINDS APPROACHING 20 KT OVERNIGHT.
WILL NOT GO TO THAT EXTREME BUT WILL INDICATE INCREASING TO
SUSTAINED AROUND 15 KT...WITH GUSTS UP TO 20 KT. SFC PRESSURE
PATTERN AHEAD OF THE COLD FRONT TO YIELD A SW DIRECTION THIS
EVENING...BECOMING WSW TOWARD DAYBREAK AS THE FRONT MOVES IN CLOSER
PROXIMITY. SIGNIFICANT SEAS OF 2 TO 3 FT THRUOUT THIS EVENING...WITH
4 FOOTERS POSSIBLE ACROSS THE OUTER WATERS OFF CAPE FEAR AND THE
EASTERN PORTIONS OF AMZ252...IE. EAST OF HOLDEN BEACH...DURING THE
FRI AM HOURS. THE 8 TO 9 SECOND PERIOD EASTERLY GROUND SWELL WILL
DOMINATE THIS EVENING...HOWEVER THERE WILL BE AN INFLUX/INCREASE OF
3 TO 6 SECOND PERIOD WIND DRIVEN WAVES...MAINLY AFTER MIDNIGHT.
HENCE...THE 4 FOOTERS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM
THURSDAY...COLD FRONT WILL DROP SOUTHEAST INTO THE WATERS ON
FRIDAY BUT WINDS WILL BACK SOME THROUGH THE DAY AS SEA BREEZE
DEVELOPS. THEN BY NIGHTFALL...WINDS WILL SWING AROUND TO THE
NORTHEAST UP TO 10 TO 15 KTS AS BOUNDARY PUSHES SOUTH. EXPECT A
SURGE OF COOLER AND DRIER AIR ADVECTING IN AS COOL CANADIAN HIGH
PRESSURE BUILDS INTO AREA BEHIND THE FRONT.
EXPECT A SECONDARY PUSH OF COOL AND DRY AIR ON SAT AS MID TO
UPPER TROUGH SWINGS OFF THE COAST AND HIGH PRESSURE CONTINUES TO
BUILD SOUTH PRODUCING A DEEPER DRIER AND COOLER NORTHERLY FLOW.
THIS SECONDARY SURGE SHOULD PRODUCE WINDS UP TO 15 TO 20 KTS WITH
HIGHER GUSTS LATE SATURDAY INTO EARLY SUNDAY. SEAS WILL INCREASE
FROM 2 TO 3 FT EARLY FRI TO 3-5 FEET FRI NIGHT INTO SATURDAY AS
WINDS INCREASE. LATEST WNA MODELS SHOW SEAS PEAKING AROUND 5 FT
POSSIBLY WARRANTING A SCEC HEADLINE...BUT THE SEAS COULD END UP BEING
HIGHER IF SURGE PRODUCES GREATER WINDS IN WELL MIXED ATMOSPHERE DUE
TO WARMER WATERS THIS TIME OF YEAR.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...NORTHEAST FLOW BETWEEN 10 AND 15 KT AT THE
START OF THE PERIOD WILL VEER TO EASTERLY AS HIGH TO THE NORTH
SHIFTS EAST. LITTLE CHANGE TO THE GRADIENT IS EXPECTED AND WINDS ARE
LIKELY TO REMAIN 10 TO 15 KT THROUGH SUN. WEAK EAST TO SOUTHEAST
FLOW DEVELOPS MON AS HIGH MOVES FARTHER OFFSHORE. SPEEDS AROUND 10
KT AND SOUTHERLY COMPONENT WILL BE SHORT LIVED. LATE MON/EARLY TUE A
COLD FRONT MOVES SOUTH ACROSS THE WATERS FOLLOWED BY HIGH PRESSURE
BUILDING IN FROM THE NORTHWEST. NORTH TO NORTHEAST FLOW DEVELOPS
WITH SPEEDS A SOLID 15 KT TUE. SEAS START OUT 3 TO 4 FT BUT DROP TO
2 TO 3 FT FOR MON AS WIND SPEEDS DECREASE. INCREASING NORTHEAST FLOW
MON NIGHT AND TUE WILL PUSH SEAS BACK TO 2 TO 4 FT BY THE END OF THE
PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DCH/TRA
SHORT TERM...RGZ
LONG TERM...III
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
230 AM EDT FRI SEP 13 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO PUSH SOUTHEAST AND OFF THE MID
ATLANTIC COAST LATER TONIGHT. ANOTHER TASTE OF FALL WILL ARRIVE
IN THE WAKE OF THIS FRONT...WITH BELOW NORMAL TEMPERATURES
EXPECTED FROM FRIDAY THROUGH THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
MESO ANAL INDICATES THE COLD FRONT IS ALL BUT CLEAR OF MY SERN
ZONES...WHERE DEWPOINTS ARE STILL HIGH BUT WILL BEGIN DROPPING
OFF OVER THE NEXT FEW HOURS. A WEAK SECONDARY SHORTWAVE IS EVIDENT
ON WATER VAPOR ENTERING NWRN PA...AND IS TRIGGERING SOME LIGHT
SHOWER ACTIVITY. HRRR AND RAP SHOW THESE SHOWERS CONTINUING TO
SLIDE EAST...WHILE TENDING TO DIMINISH IN COVERAGE SOUTH OF ABOUT
RTE-80 AND EAST OF THE LAURELS.
OVERALL WE WILL KEEP A FAIR AMOUNT OF CLOUDS. IT WILL BE BREEZY
WITH SCATTERED SHOWERS...MAINLY OVER WESTERN AREAS. STRONG COLD
ADVECTION WHICH WILL ALLOW TEMPS TO DROP INTO THE 40S IN THE N AND
50S MOST ELSEWHERE.
THE INSTABILITY SHOULD DRIVE ADDITIONAL SHOWERS AND PERHAPS THUNDER
OVER THE ALLEGHENIES - BUT WILL LEAVE THUNDER OUT FOR NOW. TEMPS
WON/T RISE MUCH ON FRI...WITH THE NEG TEMP ADV AND CLOUDS IN THE
NWRN 1/2 TO 2/3RDS OF THE AREA. EXPECT HIGHS ONLY IN THE LOWER/MID
50S IN BRADFORD AND UPPER 50S IN THE LAURELS. THE TEMPS WILL BE MORE
NORMAL IN THE DOWNSLOPE OF THE SE. GUSTY WINDS WILL MAKE IT FEEL
EVEN MUCH COOLER.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
THERE WILL BE THE POTENTIAL FOR AT LEAST PATCHY FROST OVER THE
NORMALLY COLD NORTH TONIGHT. BIGGEST QUESTION IS IF CLOUDS CAN
BREAK IN TIME. FCST SOUNDINGS CONFLICT ON THIS WITH THE GFS
SHOWING LOW LEVEL MOISTURE HANGING TOUGH...AND THE NAM SHOWING
CLEARING IN THE 06-09Z TIMEFRAME. WILL PROBABLY MENTION PATCHY
FROST LATE...BUT LEAN AWAY FROM HEADLINES AT THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
GENERALLY WESTERLY FLOW ALOFT THROUGH THE LONG TERM PERIOD WILL
CONTINUE MAINLY RAIN FREE CONDITIONS THROUGH THE PERIOD...WITH TWO
LARGE AREAS OF HIGH PRESSURE MOVING SOUTHEAST OUT OF CENTRAL
CANADA AND ACROSS PA DURING THE NEXT WEEK.
A WEAK COLD FRONT IS PROGGED TO MOVE THROUGH ON MONDAY BETWEEN
THE HIGH CENTERS...BUT GUIDANCE CONTINUES TO SUGGEST THAT IT WILL
BE MOISTURE STARVED AND KEPT POPS MINIMAL. THE HIGHEST CHANCE OF
PCPN IN THE LONG TERM PERIOD IS AT THE END OF THE PERIOD WHEN HIGH
PRESSURE MOVES OFF THE EAST COAST AHEAD OF LOW PRESSURE EXPECTED TO
FORM OVER THE NORTHERN PLAINS. RETURN FLOW ON THE BACK SIDE OF THE
HIGH WILL ALLOW A FLOW OF MOISTURE ENOUGH TO INCLUDE ISOLD/SCT
POPS INTO THE GRIDS FOR NEXT THURS.
ALSO NOTABLY...TEMPERATURES WILL DROP BACK TO BELOW NORMAL LEVELS.
HIGH TEMPERATURES WILL BE IN THE 60S AND 70S ON SUNDAY THROUGH
MUCH OF THE PERIOD.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
COLD FRONT HAS PUSHED SE OF PENNSYLVANIA AS OF 06Z AND A DRIER NW
FLOW IS TAKING HOLD. REGIONAL RADAR LOOP AT 06Z SHOWS AN AREA OF
SHOWERS ENTERING WESTERN PA IN ASSOCIATION WITH AN UPPER LVL
DISTURBANCE. THESE SHOWERS WILL LIKELY AFFECT JST BTWN
08Z-11Z...THEN FALL APART AS THEY PUSH EAST OF THE MTNS. THE
BIGGEST AVIATION CONCERN OVERNIGHT WILL BE RESIDUAL LOW LVL MOISTURE
ASCENDING THE W MTNS AND CAUSING SOME LOW CIGS. LATEST MDL
SOUNDINGS SUPPORT THE LIKELIHOOD OF IFR CIGS AT BFD AND
POSSIBILITY OF IFR CIGS AT JST LATER THIS AM.
HEATING OF BLYR WILL CAUSE CIGS TO RISE LATE THIS MORNING...WITH
VFR CONDS EXPECTED EVEN ACROSS THE W MTNS BY AFTN. ONLY AVIATION
CONCERN THIS AFTN WILL BE THE GUSTY NW WINDS CAUSED BY TIGHT PRES
GRADIENT BTWN LOW OVR NEW ENG AND HIGH PRES OVR THE MIDWEST.
BUFKIT SOUNDINGS SUPPORT FREQUENT GUSTS IN THE 15-20KT RANGE. THE
WIND WILL DIMINISH TONIGHT...AS HIGH PRES APPROACHES FROM THE
MIDWEST.
OUTLOOK...
SAT...NO SIG WX EXPECTED.
SUN...PATCHY AM FOG POSSIBLE.
MON...EARLY AM LOW CIGS POSS AT BFD.
TUE...PATCHY AM FOG POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
134 AM EDT FRI SEP 13 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO PUSH SOUTHEAST AND OFF THE MID
ATLANTIC COAST LATER TONIGHT. ANOTHER TASTE OF FALL WILL ARRIVE
IN THE WAKE OF THIS FRONT...WITH BELOW NORMAL TEMPERATURES
EXPECTED FROM FRIDAY THROUGH THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
MESO ANAL INDICATES THE COLD FRONT IS ALL BUT CLEAR OF MY SERN
ZONES...WHERE DEWPOINTS ARE STILL HIGH BUT WILL BEGIN DROPPING
OFF OVER THE NEXT FEW HOURS. A WEAK SECONDARY SHORTWAVE IS EVIDENT
ON WATER VAPOR ENTERING NWRN PA...AND IS TRIGGERING SOME LIGHT
SHOWER ACTIVITY. HRRR AND RAP SHOW THESE SHOWERS CONTINUING TO
SLIDE EAST...WHILE TENDING TO DIMINISH IN COVERAGE SOUTH OF ABOUT
RTE-80 AND EAST OF THE LAURELS.
OVERALL WE WILL KEEP A FAIR AMOUNT OF CLOUDS. IT WILL BE BREEZY
WITH SCATTERED SHOWERS...MAINLY OVER WESTERN AREAS. STRONG COLD
ADVECTION WHICH WILL ALLOW TEMPS TO DROP INTO THE 40S IN THE N AND
50S MOST ELSEWHERE.
THE INSTABILITY SHOULD DRIVE ADDITIONAL SHOWERS AND PERHAPS THUNDER
OVER THE ALLEGHENIES - BUT WILL LEAVE THUNDER OUT FOR NOW. TEMPS
WON/T RISE MUCH ON FRI...WITH THE NEG TEMP ADV AND CLOUDS IN THE
NWRN 1/2 TO 2/3RDS OF THE AREA. EXPECT HIGHS ONLY IN THE LOWER/MID
50S IN BRADFORD AND UPPER 50S IN THE LAURELS. THE TEMPS WILL BE MORE
NORMAL IN THE DOWNSLOPE OF THE SE. GUSTY WINDS WILL MAKE IT FEEL
EVEN MUCH COOLER.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
THERE WILL BE THE POTENTIAL FOR AT LEAST PATCHY FROST OVER THE
NORMALLY COLD NORTH TONIGHT. BIGGEST QUESTION IS IF CLOUDS CAN
BREAK IN TIME. FCST SOUNDINGS CONFLICT ON THIS WITH THE GFS
SHOWING LOW LEVEL MOISTURE HANGING TOUGH...AND THE NAM SHOWING
CLEARING IN THE 06-09Z TIMEFRAME. WILL PROBABLY MENTION PATCHY
FROST LATE...BUT LEAN AWAY FROM HEADLINES AT THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
GENERALLY WESTERLY FLOW ALOFT THROUGH THE LONG TERM PERIOD WILL
CONTINUE MAINLY RAIN FREE CONDITIONS THROUGH THE PERIOD...WITH TWO
LARGE AREAS OF HIGH PRESSURE MOVING SOUTHEAST OUT OF CENTRAL
CANADA AND ACROSS PA DURING THE NEXT WEEK.
A WEAK COLD FRONT IS PROGGED TO MOVE THROUGH ON MONDAY BETWEEN
THE HIGH CENTERS...BUT GUIDANCE CONTINUES TO SUGGEST THAT IT WILL
BE MOISTURE STARVED AND KEPT POPS MINIMAL. THE HIGHEST CHANCE OF
PCPN IN THE LONG TERM PERIOD IS AT THE END OF THE PERIOD WHEN HIGH
PRESSURE MOVES OFF THE EAST COAST AHEAD OF LOW PRESSURE EXPECTED TO
FORM OVER THE NORTHERN PLAINS. RETURN FLOW ON THE BACK SIDE OF THE
HIGH WILL ALLOW A FLOW OF MOISTURE ENOUGH TO INCLUDE ISOLD/SCT
POPS INTO THE GRIDS FOR NEXT THURS.
ALSO NOTABLY...TEMPERATURES WILL DROP BACK TO BELOW NORMAL LEVELS.
HIGH TEMPERATURES WILL BE IN THE 60S AND 70S ON SUNDAY THROUGH
MUCH OF THE PERIOD.
&&
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
SFC COLD FRONT EXTENDED FROM NEAR KELM TO KIDI ATTM. THE FRONT
WILL MOVE SE AN CLEAR THE SERN TAF SITES /KMDT AND KLNS/ BETWEEN
05-06Z. MAINLY VFR CONDITIONS WERE SPREAD ACROSS THE CENTRAL
ZONES...WHILE SOME MVFR VSBYS WERE NOTED ACROSS THE LOWER SUSQ
VALLEY...AND MVFR CIGS OVER THE LAURELS.
AS THE COLDER AIR DEEPENS...CIGS AND VSBYS WILL DROP A BIT /TO
MAINLY IFR ACROSS THE WRN MTNS FOR SEVERAL HOURS WELL AFTER
MIDNIGHT/...LOW END MVFR VSBYS AND PERIODS OF MVFR CIGS DEVELOPING
ELSEWHERE. A COMPACT...BUT RATHER POTENT UPPER AIR DISTURBANCE
HEADING QUICKLY TO THE ESE ACROSS LAKE ERIE AND OHIO WILL SUPPORT
AN AREA OF SHOWERS AND A FEW TSRA...THAT SHOULD WEAKEN AS THEY
MOVE WELL INLAND FROM THE WARM LAKE ERIE WATERS. STILL EXPECT
SHOWERS LATE TONIGHT TO BE FOCUSED FOR A FEW HOURS ACROSS THE
LAUREL HIGHLANDS.
SHORT STATURE AND BRIEF DURATION/CLOSED CELLULAR BUT INTENSE
CONVECTION IS POSSIBLE ON FRI - MAINLY IN THE AFTN AS THE COLDEST
AIR ALOFT AND THE STRONGEST SHORT WAVE TROUGH CROSSES THE AREA.
THE MOST LIKELY TERMINALS WHICH MIGHT SEE SOME IMPACT WILL BE JST
AND BFD. WINDS WILL STAY UP A LITTLE TONIGHT AND PICK UP AND GUST
INTO THE 20-25KT RANGE DURING THE DAY AND MAYBE A LITTLE STRONGER
IN THE AFTN FRI.
OUTLOOK...
SAT...NO SIG WX EXPECTED.
SUN...PATCHY AM FOG POSSIBLE...OTHERWISE VFR.
SUN PM-MON AM...ISOLD SHRA POSS.
MON PM...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...DANGELO/RXR
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
338 AM MDT SUN SEP 15 2013
.SHORT TERM...REMNANTS OF WK UPPER LEVEL TROUGH WILL SHEAR ACROSS THE
AREA THRU TONIGHT WITH SOME MINOR MID LVL ASCENT. MEANWHILE LOW
LVL WINDS ARE CURRENTLY NLY ALONG THE FNT RANGE BUT ARE FCST TO
BECOME MORE NELY LATER THIS MORNING INTO THE AFTN HOURS BEHIND A
COOL FNT. THIS SHOULD ALLOW FOR INCREASING PCPN IN THE NRN
FOOTHILLS AND MTNS EAST OF THE DIVIDE THIS MORNING WHICH WILL
SPREAD SOUTHWARD THRU THE DAY. AT THIS TIME HIGHEST PCPN AMOUNTS
SHOULD FOCUS IN AND NR THE FOOTHILLS AND IN THE MTNS EAST OF THE
DIVIDE. THE GFS AND HRRR SHOW POTENTIAL RAINFALL AMOUNTS RANGING
FROM 1 TO 2 INCHES OVER THE HIGHER TERRAIN WHILE THE ECMWF KEEPS
THE HEAVIER AMOUNTS FOCUSED EAST OF THE HIGHER TERRAIN OVER THE
FRONT RANGE URBAN CORRIDOR THRU THIS AFTN. AT THIS POINT WILL KEEP
THE HEAVIER AMOUNTS OVER THE HIGHER TERRAIN.
MEANWHILE WITH CONSIDERABLE CLOUD COVER THERE WILL BE LIMITED
INSTABILITY SO THE PCPN WILL BE MORE OF A STRATIFORM EVENT WITH
RAINFALL RATES MAINLY AROUND ONE QUARTER INCH PER HOUR. WILL KEEP
FFA IN PLACE HOWEVER BIGGWST CONCERNS WOULD BE CONSIDERABLE AMOUNT
OF ROCK AND MUD SLIDE ACTIVITY DUE TO EXTREMELY SATURATED GROUND.
HIGH THIS AFTERNOON OVER NERN CO MAY NOT GET MUCH ABV 60 EXCEPT OVER
THE FAR NERN CORNER WHERE HIGHS MAY GET CLOSE TO 70.
FOR TONIGHT THERE WILL BE SOME LINGERING RAIN THEU EVENING WHICH
WILL GRADUALLY END FM NORTH TO SOUTH OVERNIGHT. TEMPS MAY BE COLD
ENOUGH FOR SOME SNOW OVER THE HIGHER MTNS ABV 11000 FT BEFORE PCPN
ENDS.
.LONG TERM...MODELS SHOW THE WEAK UPPER TROUGH TO MOVE ACROSS THE
FORECAST AREA ON MONDAY...THEN UPPER RIDGING IS PROGGED INTO
TUESDAY AFTERNOON. SOUTHWESTERLY FLOW ALOFT MOVES IN TUESDAY
NIGHT...WITH AN UPPER TROUGH GETTING INTO THE NORTHERN GREAT BASIN
BY 12Z WEDNESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA MONDAY THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER PRESSURE AND WIND FIELDS SHOW SOUTHEASTERLIES
OVER THE PLAINS ON MONDAY...THEN NORMAL DIURNAL PATTERNS KICK IN
MONDAY NIGHT INTO TUESDAY. LOW LEVEL TROUGHING AND DOWNSLOPING ARE
BOTH PROGGED LATER TUESDAY INTO TUESDAY NIGHT. CONCERNING MOISTURE
...MONDAY DRIES OUT SOMEWHAT...WITH FURTHER DRYING ON TUESDAY.
PRECIPITABLE WATER VALUES ARE IN THE 0.75-0.85 INCH RANGE OVER THE
WESTERN PLAINS MONDAY...DRYING INTO THE 0.50 TO 0.75 INCH RANGE
BY LATER TUESDAY. VALUES ARE HIGHER OVER THE EASTERN PLAINS ON
MONDAY...BUT DRY TO SIMILAR VALUES BY LATER TUESDAY. THE BOUNDARY
LAYER DEW POINTS ARE PROGGED IN THE LOWER TO MID 50S F OVER THE
PLAINS MONDAY INTO TUESDAY MONRING...THEN THEY DECREASE INTO THE
40S TO LOWER 50S F LATER TUESDAY AND TUESDAY NIGHT. VALUES ARE IN
THE MID 30S TO MID 40S OVER THE MOUNTAINS ALL FOUR PERIODS. THERE
IS SOME CAPE AROUND BOTH LATE DAY MONDAY AND LATE DAY TUESDAY...
BUT NOTHING SIGNIFICANT. THE QPF FIELDS HAVE LIMITED MEASURABLE
RAINFALL AMOUNTS MONDAY...NOTHING MONDAY NIGHT OR TUESDAY MONRING
...THEN A TAD LATE DAY TUESDAY IN THE MOUNTAINS. SO FOR POPS...
20-40%S IN THE MOUNTAINS LATE DAY MONDAY AND LATE DAY TUESDAY. FOR
THE PLAINS...10-20%S LATE DAY MONDAY...NONE TUESDAY. FOR
TEMPERATURES...MONDAY`S HIGHS ARE 3-7 C WARMER THAN TODAY`S.
TUESDAY`S HIGHS ARE 1-4 C WARMER THAN MONDAY`S. FOR THE LATER DAYS
...WEDNESDAY THROUGH SATURDAY...MODELS BRING AN UPPER TROUGH ACROSS
THE CWA WEDNESDAY AFTERNOON INTO EARLY THURSDAY...ALONG WITH AN
ACCOMPANYING COLD FRONT. AFTER THAT...UPPER RIDGING MOVES IN
THROUGH SATURDAY. MOISTURE IS LIMITED AND TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
&&
.AVIATION...CEILINGS SHOULD GRADUALLY DROP INTO THE IFR CATEGORY LATER
THIS MORNING WITH AREAS OF RAIN DEVELOPING. THIS ACTIVITY WILL
CONTINUE THRU THE AFTN BEFORE ENDING DURING THE EVENING HOURS.
OVERNIGHT LOW CEILINGS AND SOME FOG WILL BE POSSIBLE THRU MON
MORNING.
&&
.HYDROLOGY...WILL CONTINUE WITH THE FLASH FLOOD WATCH THROUGH 6 PM
THIS EVENING. AREAS OF RAIN WILL INCREASE THROUGH THE MORNING
HOURS AND CONTINUE THROUGH THE AFTERNOON IN THE MOUNTAINS AND
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDER. RAINFALL
AMOUNTS OVER THE HIGHER TERRAIN THROUGH 6 PM MAY RANGE FROM 1 TO 2
INCHES WITH ONE HALF INCH TO ONE INCH AT LOWER ELEVATIONS. COULD
SEE A FEW LOCALIZED AREAS OF FLASH FLOODING HOWEVER BIGGEST
CONCERN WILL BE AN INCREASE IN ROCK AND MUD SLIDES IN THE
FOOTHILLS AND MOUNTAINS DUE TO EXTREMELY SATURATED GROUND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR COZ033>036-038>041-
043.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
117 AM EDT SUN SEP 15 2013
.AVIATION...
ISOLATED SHOWERS WILL CONTINUE TO DEVELOP OVER THE ATLANTIC WATERS
AND WORK INTO THE EAST COAST TAF SITES BEFORE DISSIPATING. SO HAVE
ADDED VCSH FOR ALL OF THE EAST COAST TAF SITES FOR THE EARLY
MORNING HOURS. THE SHOWERS WILL CONTINUE THROUGH THE MORNING HOURS
ON SUNDAY...BEFORE THUNDERSTORMS DEVELOP DURING THE AFTERNOON
HOURS ALONG THE SEA BREEZES. SO HAVE KEPT THE VCTS FOR THE EAST
COAST TAF SITES FOR THE SUNDAY AFTERNOON HOURS ALONG WITH VCTS FOR
KAPF TAF SITE FOR THE LATE MORNING INTO THE AFTERNOON HOURS.
THE WINDS WILL REMAIN EASTERLY AT ALL OF THE TAF SITES THROUGH
SUNDAY NIGHT...AS SPEEDS WILL BE 5 KNOTS OR LESS THROUGH 14Z
BEFORE INCREASING TO AROUND 10 KNOTS BY SUNDAY AFTERNOON. THE
CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS THROUGH
SUNDAY AFTERNOON...AS THE TIMING OF THE SHOWERS AND THUNDERSTORMS
IS NOT KNOWN AT THIS TIME. SO WILL ADMIN THE TAFS WHEN THERE IS A
THREAT FOR SHOWERS OR THUNDERSTORMS FOR THE CEILING AND VIS.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 843 PM EDT SAT SEP 14 2013/
UPDATE...
CONDITIONS ARE QUIETING DOWN ACROSS SOUTH FLORIDA THIS EVENING.
CURRENT POPS ARE IN GOOD SHAPE. THERE ARE SOME SHOWERS AND A FEW
THUNDERSTORMS THAT WILL PROBABLY AFFECT THE ATLANTIC COASTAL
WATERS TONIGHT, BUT MOST SHOULD REMAIN WELL OFFSHORE. NO MAJOR
CHANGES MADE TO THE FORECAST WITH THIS UPDATE.
&&
PREV DISCUSSION... /ISSUED 720 PM EDT SAT SEP 14 2013/
AVIATION...
THE WEATHER WILL BE DRY OVER ALL OF THE TAF SITES TONIGHT...AS
THE WINDS WILL BE LESS THAN 5 KNOTS FROM THE EAST. THE WINDS WILL
THEN INCREASE TO AROUND 10 KNOTS ON SUNDAY FROM THE EAST AT ALL OF
SOUTH FLORIDA TAF SITES ALONG WITH SOME SHOWERS IN THE MORNING AND
THUNDERSTORMS IN THE AFTERNOON. SO WILL ADD VCSH TO ALL OF THE TAF
SITES AFTER 14Z AND VCTS AFTER 17Z...EXCEPT FOR KAPF TAF SITE
WHERE VCTS WILL BE PUT IN AFTER 15Z ON SUNDAY. THE CEILING AND VIS
WILL ALSO REMAIN IN THE VFR CONDITIONS TONIGHT INTO SUNDAY...AS
THE TIMING OF THE SHOWERS AND THUNDERSTORMS ON SUNDAY IS NOT KNOWN
AT THIS TIME.
&&
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 236 PM EDT SAT SEP 14 2013/
SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE REGION WILL ESTABLISH MODEST
BUT DEEP EASTERLY FLOW OVER SOUTH FLORIDA FOR MUCH OF NEXT WEEK.
THIS WILL ADVECT TROPICAL MOISTURE INTO THE AREA...RESULTING IN
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
SAL APPEARS TO BE SUCCESSFULLY SUPPRESSING CONVECTION TODAY OVER
MOST OF SOUTH FLORIDA. EASTERLY FLOW IS A BIT STRONGER TODAY THAN
YESTERDAY...SO GULF BREEZE HAS BEEN SLOW TO DEVELOP...WHILE
ATLANTIC BREEZE IS NOW INLAND OF METRO EAST COAST METRO AREAS.
ISOLATED TO SCATTERED CONVECTION IS STILL EXPECTED ALONG AND AHEAD
OF EITHER SEA-BREEZE...WITH GREATEST COVERAGE NEAR/WEST OF LAKE
OKEECHOBEE...WHERE LOW/MID-LEVELS ARE LEAST DRY AND DUST LAYER IS
LESS SIGNIFICANT. 18Z VSB SATELLITE ALREADY DEPICTS SIGNIFICANT CU
FIELD IN THIS REGION...AND HRRR FORECAST COMPOSITE REFLECTIVITY IS
MORE IMPRESSIVE THAN WAS INDICTED YESTERDAY AT THIS TIME. EXPECT
ACTIVITY TO HAVE SLOW SOUTHWARD DRIFT...THOUGH WITH LOW PWATS
FLOODING IS NOT A SIGNIFICANT THREAT. FORECAST AND 12Z SOUNDING
WERE NOT PARTICULARLY FAVORABLE FOR ANYTHING STRONGER THAN TYPICAL
SUMMERTIME CONVECTION...SO WILL LEAVE HWO MENTIONING FREQUENT
CLOUD-TO-GROUND LIGHTNING AS MAIN THREAT. CONVECTION WILL
DIURNALLY WANE.
UPPER-LEVEL TROUGH OVER EASTERN CONUS LIFTS NORTHWARD
TONIGHT...ALLOWING DEEP LAYER HIGH PRESSURE TO BUILD OVER THE
SOUTHEAST UNITED STATES AND ADJACENT ATLANTIC. WITH THE RIDGE AXIS
NORTH OF SOUTH FLORIDA...DEEP EASTERLY FLOW WILL
ESTABLISH...USHERING IN GREATER MOISTURE AND CAUSING AN UPWARD-
TREND IN POPS SUNDAY INTO MONDAY. SCATTERED TO PERHAPS NUMEROUS
CONVECTION IS EXPECTED BOTH AFTERNOONS. TEMPERATURES WILL BE
SOMEWHAT REGULATED BY THE INCREASE IN PCPN/CLOUDS...BUT OVERALL
WILL REMAIN NEAR NORMAL FOR MID-SEPTEMBER.
LONG TERM /TUESDAY THROUGH FRIDAY...
SIMILAR SYNOPTIC CONDITIONS WILL PERSIST THROUGH MUCH OF THE
PERIOD WITH MODELS PROJECTING LIKELY POPS. FOR NOW...CAPPING RAIN
CHANCES AT THIS TIME IN THE 40-50% RANGE. IN THE LATTER HALF OF
THE WEEK LOW LEVEL RIDGE PERSISTS AND WITH MOISTURE LEVELS
REMAINING CLOSE TO NORMAL RAIN CHANCES ARE FORECAST TO BE NEAR
CLIMO WITH DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS FORECAST
WEDNESDAY THROUGH FRIDAY. AS IN THE SHORT RANGE...TEMPERATURE
PATTERN OF NEARLY NORMAL DAYTIME HIGHS AND ABOVE NORMAL OVERNIGHT
LOWS WILL PERSIST.
MARINE...
EAST WINDS OF 5-15 KTS WILL PREVAIL FOR MOST OF THE NEXT 5 DAYS.
SEAS WILL BE 3 FEET OR LESS. SCATTERED THUNDERSTORMS SHOULD BE
PRESENT OVER THE WATERS BEGINNING SUNDAY AFTERNOON AND CONTINUE
THROUGH AT LEAST MID-WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 89 77 88 / 30 50 40 50
FORT LAUDERDALE 80 90 77 89 / 30 50 40 50
MIAMI 79 89 77 90 / 30 50 40 50
NAPLES 76 91 77 90 / 30 50 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...23/SK
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
409 AM CDT Sun Sep 15 2013
...Updated for short term discussion...
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1259 AM CDT SUN SEP 15 2013
A cold front will approach KHYS around 18z, KGCK around 21z and
KDDC by 22z. Thunderstorms may affect KDDC along the front between
22-24z. Otherwise, south winds will shift to the southwest at
10-15 kts by 15z and then north-northeast at 12-17kts behind the
cold front. IFR CIGS may develop at KDDC by 04z as low level
upslope flow develops.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 87 61 73 63 / 30 40 40 30
GCK 81 58 72 61 / 20 30 40 30
EHA 82 60 78 62 / 30 30 40 40
LBL 85 63 77 62 / 30 30 40 40
HYS 82 58 71 62 / 10 30 30 40
P28 93 65 79 66 / 40 40 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Finch
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1146 PM MDT SAT SEP 14 2013
.UPDATE...
ISSUED AT 757 PM MDT SAT SEP 14 2013
JUST COMPLETED AN UPDATE. MAIN CHANGE WAS READJUST THE POP FIELD.
MAJORITY OF THE MODELS AND FORECAST WAS EMPHASIZING THE SOUTHEAST
PORTION OF THE AREA. PER MESOANALYSIS AND MODEL DATA ALONG WITH
REALITY MAIN AREA OF THUNDERSTORMS LOOKS TO INITIALLY BE THE
NORTHWEST CORNER AND THEN SPREADING EAST ACROSS THE REMAINDER OF
THE NORTHERN TIER OF COUNTIES. THIS IS WHERE PREFRONTAL SURFACE
TROUGH AND THEN COLD FRONT WILL COINCIDE WITH THE DEEPEST MOISTURE
AND MID/UPPER LEVEL LIFT.
SOUTHEAST PORTION OF THE AREA LOOKS CAPPED. HOWEVER THAT SHOULD
CHANGE BY LATER TONIGHT. THE HRRR FOLLOWED BY THE GFS WAS CATCHING
THE PRECIPITATION FIELD THE BEST. ALSO ADJUSTED THE SKY COVER AND
WIND PER LATEST TRENDS AND MESOSCALE MODEL DATA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM MDT SAT SEP 14 2013
A SURFACE LEE TROUGH IS DEEPENING AND MOVING EASTWARD ACROSS THE
FORECAST AREA THIS AFTERNOON IN RESPONSE TO A COUPLE OF WEAK SHORT
WAVES ROTATING AROUND THE MAIN UPPER LOW THAT IS VERY SLOW TO LIFT
OUT OF THE INTERMOUNTAIN REGION. THIS SURFACE TROUGH IS IN ADVANCE
OF A COLD FRONT THAT PUSHES SOUTHWARD INTO THE REGION ON SUNDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG AND EAST OF THE SURFACE TROUGH THIS LATE THIS AFTERNOON AND
EVENING ALONG WITH WITH A FEW STORMS DEVELOPING OVER THE FRONT RANGE
MOVING EAST OVER THE PLAINS THAT ARE EXPECTED TO DIMINISH THIS
EVENING. SCATTERED STORMS WILL DEVELOP AGAIN SUNDAY AFTERNOON
MAINLY IN THE VICINITY OF THE FRONT AS IT PUSHES SOUTH ACROSS THE
FORECAST AREA. LIGHT TO MODERATE RAINFALL IS EXPECTED WITH THESE
STORMS...WHICH COULD PRODUCE LOCALIZED AREAS OF FLOWING WATER IN
STREAM BEDS THAT ARE EITHER NORMALLY DRY OR STILL HAVE SOME WATER IN
THEM REMAINING FROM THE RECENT HEAVY RAINFALLS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 250 PM MDT SAT SEP 14 2013
SUNDAY NIGHT THROUGH MONDAY NIGHT NUMEROUS UPPER LEVEL SHORT WAVE
TROUGHS WILL MOVE OVER THE AREA. THE ENVIRONMENT WILL HAVE SOME
CONVECTIVE INSTABILITY AND THE PLUME OF SUBTROPICAL MOISTURE WILL
PERSIST OVER THE AREA UNTIL MONDAY NIGHT. THE STRONGEST UPPER LEVEL
TROUGH WITH THE BEST INSTABILITY WILL MOVE OVER THE AREA SUNDAY
NIGHT. DIFFICULT TO BE TOO EXCITED ABOUT PRECIP. CHANCES GIVEN THE
LIFT ASSOCIATED WITH THE TROUGH IS ON THE WEAKER SIDE. HOWEVER THE
LAST FEW DAYS HAVE HAD GOOD STORM DEVELOPMENT WITH RATHER BENIGN
LOOKING SHORT WAVE TROUGHS. MONDAY THE CONVECTIVE INSTABILITY
DIMINISHES SOME AND THE SHORT WAVE TROUGHS LOOK WEAKER...SO WILL
HAVE LOWER PRECIP. CHANCES AS A RESULT...WITH CHANCES ENDING FROM
WEST TO EAST AS DRIER AIR MOVES IN MONDAY EVENING. MEANWHILE THE COLD
FRONT FROM SUNDAY WILL MOVE IN FROM THE WEST AS A WARM FRONT AND
STALL OVER THE AREA MONDAY NIGHT. SLOW STORM MOTIONS WILL LEAD TO A
THREAT FOR HEAVY RAINFALL.
TUESDAY THROUGH SATURDAY THE NEXT BEST CHANCE FOR RAINFALL WILL BE
WEDNESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE AREA WHILE AN
UPPER LEVEL LOW MOVES ACROSS THE NORTHERN PLAINS. WITH THE TRI-
STATE AREA BEING ON THE FAR SOUTHERN SIDE OF THE LOW...PRECIP.
CHANCES WILL BE CONFINED TO THE FRONTAL PASSAGE. BEHIND THE UPPER
LEVEL LOW A RIDGE WILL BUILD OVER THE AREA FOR THE WEEKEND.
TEMPERATURES FOR THE PERIOD WILL START OUT ABOVE NORMAL AS A WARM
FRONT MOVES THROUGH THE AREA FROM THE WEST TUESDAY. NEAR NORMAL
TEMPERATURES RETURN BEHIND THE COLD FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM MDT SAT SEP 14 2013
CHAOTIC/VARIABLE CONDITIONS EXPECTED THROUGH THE PERIOD. INITIALLY
EXPECT THUNDERSTORMS TO AFFECT THE KMCK WITH CONDITIONS NEARING
MVFR IF A STRONG ENOUGH THUNDERSTORM COMES ACROSS. INITIALLY WINDS
WILL BE VARIABLE DUE TO THUNDERSTORM OUTFLOW AND THE PASSAGE OF
THE PREFRONTAL TROUGH BEFORE A STRONGER WIND SHIFT WITH THAT FRONT.
FRONT WILL MOVE THROUGH THE TAF SITES IN THE 12Z TO 14Z TIME FRAME
WITH GUSTY WINDS BEHIND IT UNTIL EARLY AFTERNOON.
BEHIND THE FRONT AT LEAST MVFR CEILINGS IN STRATUS ARE EXPECTED.
MODEL GUIDANCE IS SIMILAR TO WHAT IS UPSTREAM BEHIND THE FRONT.
ALTHOUGH SOME MODEL OUTPUT HAS CEILINGS BREIFLY GOING INTO IFR.
CEILINGS WILL RISE AND WINDS WILL DECREASE IN THE AFTERNOON. AT
THIS TIME IT LOOKS LIKE MVFR CEILINGS WILL LAST AT KGLD UNTIL THE
END OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...JTL
LONG TERM...JTL
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EDT SUN SEP 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE NRN ROCKIES
AND A TROUGH OVER HUDSON BAY RESULTING IN CYCLONIC WNW FLOW THROUGH
THE NRN GREAT LAKES. A SHORTWAVE TROUGH OVER MN AND AREA OF UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 250-300 MB JET OVER NRN
ONTARIO SUPPORTED A LARGE AREA OF RAIN FROM SE MN THROUGH UPPER MI
AND WI. THE STRONGEST 700-500 MB QVECTOR CONV AND HEAVIER PCPN
REMAINED TO THE SOUTH OVER WI. HOWEVER...300K-305K ISENTROPIC LIFT
EXTENDING INTO UPPER MI AHEAD OF THE SFC TROUGH FROM NW IA INTO NW
WI HAS HELPED BRING LIGHT RAIN THROUGH THE CWA. WINDS HAD VEERED
SHARPLY TO THE NE AND INCREASED TO 15 TO 25 KNOTS OVER NRN LAKE
SUPERIOR BEHIND A COLD FRONT SAGGING INTO UPPER MI.
TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE SHORTWAVE AND
AREA OF WIDESPREAD RAIN WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST
AND END BY AFTERNOON. HOWEVER...THE CYCLONIC NNE FLOW AND 850 MB
TEMPS FALLING INTO THE 2C TO 4C RANGE BEFORE THE DEEPER MOISTURE
DEPARTS WILL SUPPORT SOME LAKE ENHANCED RAIN/DRIZZLE INTO N CNTRL
UPPER MI ESPECIALLY OVER THE HIGHER TERRAIN WHERE LOW LEVEL UPSLOPE
FLOW IS STRONGEST. ONCE THE DEEP MOISTURE QUICKLY MOVES OUT AROUND
18Z...THE REMAINING PCPN SHOULD END ALONG WITH DIMINISHING CLOUD
COVER.
TONIGHT...HIGH PRESSURE OVER NRN MANITOBA WHERE SOME TEMPS HAVE
FALLEN INTO THE MID AND UPPER 20S...WILL BUILD INTO UPPER MI
BRINGING CLEARING SKIES AND DIMINISHING WINDS. WITH PWAT VALUES
FALLING CLOSE TO 0.3 INCHES...FAVORABLE RADIATIONAL COOLING WILL
ALLOW TEMPS TO DROP INTO THE LOWER 30S OVER MUCH OF THE INTERIOR
WEST HALF OF UPPER MI WHERE A FROST ADVISORY WAS ISSUED. FARTHER
EAST...LINGERING NE WINDS WILL BE STRONG ENOUGH TO KEEP TEMPS FROM
DROPPING OFF AS MUCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM EDT SUN SEP 15 2013
500MB RIDGE AND SFC PRESSURE WILL CONTROL THE FIRST PORTION OF THE
LONG TERM FORECAST PERIOD. THIS RIDGE WILL MOVE FROM THE NORTHERN
PLAINS ON MONDAY MORNING INTO THE OHIO VALLEY BY TUESDAY NIGHT.
EXPECT UPPER MICHIGAN WEATHER TO BE QUITE PLEASANT MONDAY AND
TUESDAY. ON MONDAY 850MB TEMPS WILL DIP TO AROUND 3-5C...AND WINDS
WILL BE NORTHERLY OFF LAKE SUPERIOR. KEPT HIGHS IN THE UPPER 50S AND
60S ACCORDINGLY. TUESDAY 850MB TEMPS WILL CLIMB TO THE 6-10C RANGE
AND SFC WINDS WILL SWING TO THE SOUTH...RAISING AFTERNOON HIGHS INTO
THE UPPER 60S AND LOW 70S...WHICH IS NORMAL FOR THIS TIME OF YEAR.
MEANWHILE...A DEEP 500MB LOW PRESSURE TROUGH MAKES ITS WAY ONSHORE
OVER THE NORTHWESTERN UNITED STATES. THE ASSOCIATED SFC LOW DEVELOPS
OVER MONTANA BY TUESDAY AFTERNOON...AND STRONG MOISTURE
TRANSPORT BRINGS PWATS UP TO 160 PERCENT OF NORMAL INTO WESTERN
UPPER MICHIGAN BY 06Z WEDNESDAY. AS THE LOW MOVES EASTWARD INTO THE
DAKOTAS THROUGH WEDNESDAY NIGHT...EXPECT THIS AREA OF STRONGER
MOISTURE ADVECTION TO MOVE EASTWARD THROUGH THE CWA. WITH A WEAK
SHORTWAVE FLATTENING THE EXITING RIDGE...AND AREA OF MOISTURE
ADVECTION FEEL THAT CHANCE TO SLIGHT CHANCE POPS ARE WARRANTED
ACROSS UPPER MICHIGAN FOR TUESDAY NIGHT AND WEDNESDAY-WITH HIGHER
POPS LOCATED FURTHER SOUTH NEAR THE BETTER FORCING. THE BEST
INSTABILITY ARRIVES LATER WEDNESDAY MORNING INTO THE AFTERNOON...SO
LEFT THUNDER OUT UNTIL THESE TIMES.
THURSDAY INTO SUNDAY WE DEAL WITH THE ARRIVAL OF THE ACTUAL
SFC/UPPER LEVEL LOW PRESSURE SYSTEM...WHICH MODELS CURRENTLY HAVE
TRAVERSING ACROSS THE UPPER GREAT LAKES. AS USUAL...MODEL
DIFFERENCES WILL GREATLY IMPACT THE FORECAST FOR THE WEEKEND...WITH
THE ECMWF/GEM BRINGING A CUT OFF 500MB LOW ACROSS NORTHEASTERN
MINNESOTA/NORTHERN ONTARIO BY FRIDAY AFTERNOON. THE GFS HAS A
NEUTRALLY TILTED TROUGH REACHING MINNESOTA AROUND THE SAME
TIME...WITH THE SURFACE LOW OVER ONTARIO JUST SOUTH OF JAMES BAY.
DESPITE DIFFERENCES...CAN AGREE THAT THIS WILL LIKELY BE A SOGGY END
TO THE WEEK...WITH MODELS PROJECTING PWATS 160-210 PERCENT OF
NORMAL. NOT GOING TO GET CUTE WITH THE GRIDS AT THIS POINT...BUT
WILL USE THE WPC DAY 3-7 FRONTS/PRESSURE LOCATIONS AS A GUIDE UNTIL
GREATER CONSISTENCY IS ACHIEVED. THIS PUTS THE SFC LOW DIRECTLY OVER
UPPER MICHIGAN ON FRIDAY MORNING...AND OVER QUEBEC BY SATURDAY
AFTERNOON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 515 AM EDT SUN SEP 15 2013
ALTHOUGH SOME -SHRA WL IMPACT IWD AND THEN CMX EARLY THIS MRNG...
LINGERING LLVL DRY AIR WL MAINTAIN VFR CONDITIONS UNTIL LATER WHEN
THE PCPN MOISTENS THE LOWER LVLS SUFFICIENTLY AND LEADS TO MVFR
CIGS. THE PASSAGE OF A COLD FNT N-S THIS MRNG WL CAUSE A SHARP WSHFT
TO THE NNE AND BRING IFR CIGS AS SHALLOW COLD WEDGE FOLLOWS THIS
FROPA IN THE PRESENCE OF SOME -SHRA. EXPECT THE LOWEST IFR CIGS AT
SAW/IWD WHERE THE N WIND PRESENTS THE GREATEST UNSLOPE COMPONENT.
EXPECT A GRADUAL TRANSITION TO VFR WX IN THE AFTN WITH THE APRCH OF
HI PRES/ARRIVAL OF DRIER AIR. A STEADY N WIND WL DIMINISH BY THIS
EVNG WITH THE CLOSER APRCH OF THE HI/LOSS OF DAYTIME HEATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 515 AM EDT SUN SEP 15 2013
NE WINDS UP TO 30 KNOTS TODAY ARE EXPECTED BEHIND A COLD FRONT
MOVING THROUGH LAKE SUPERIOR EARLY THIS MORNING. WINDS WILL DIMINISH
LATE THIS AFTERNOON AND TONIGHT AS HIGH PRESSURE BUILDS INTO THE
AREA. WITH THE HIGH DOMINATING THE REGION MON...WINDS WILL REMAIN
BELOW 20 KNOTS. AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO
20 KNOTS ARE EXPECTED FROM TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 9 AM EDT /8 AM CDT/
MONDAY FOR MIZ002-004-005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1117 PM CDT Sat Sep 14 2013
.UPDATE:
Issued at 921 PM CDT Sat Sep 14 2013
Not any major changes to previous forecast for tonight. Have
updated hourly T grids to capture faster drop in temps than
previously forecast. However...did not drop mins as IR satellite
depicts increasing mid/high level cloudiness. Only other change of
note was to delay rain chances a few hours more in line with
latest HRRR guidance.
Gosselin
&&
.SHORT TERM: (Through Late Tonight)
Issued at 353 PM CDT Sat Sep 14 2013
Quiet weather continues in the short term as a sprawling high
pressure system over the Ohio Valley drifts east overnight. Light
and variable wind will become more southerly tonight as a result,
and increasing cloud cover from a trof of low pressure over the
Great Plains will keep temperatures from dipping to low tonight.
Guidance temperatures in the low to mid 50s look very reasonable.
The cold front approaching our area from the northwest is also
slower than expected, so have backed off pops for tonight as well.
Carney
.LONG TERM: (Sunday through Next Saturday)
Issued at 353 PM CDT Sat Sep 14 2013
Upper trough currently extending from the Hudson Bay southwestward
into northern Plains will move southeast into the southern Great
Lakes by tomorrow evening. Both the GFS and WRF based models show
that the attendant cold front will move south into the CWA reaching
close to a Pittsfield to Columbia line by 00Z, and south of the CWA
by 12Z Monday. Moisture convergence will increase along and just
ahead of the front with most of the large scale ascent coincident or
just behind the front. Will keep rain chances mainly north of I-70
during the day on Sunday and then spread them south during the
evening. Best chances will be on Sunday afternoon when best ascent
from upper trough will be lined up with best low level forcing and
instability.
Have kept slight or low chance of storms going Monday as front never
moves very far to the south. Low chances of storms still look
warranted Tuesday and Tuesday night as low level moisture convergence
will set up under shortwave trough passing through the area.
GFS/ECMWF/Canadian GEM each show that an upper trough will amplify
Wednesday into Friday as it moves from the Pacific Northwest into
Upper Midwest. The 00Z ECMWF does carve out a deeper upper low
than the more consistent GFS by late Friday. Moisture begins to
flow northward from the Gulf ahead of the trough by midweek, so will
leave in rain chances beginning Tuesday night and continue them into
Friday when a cold front moves through the area. 850mb temperatures
between 16-18C with clouds and rain chances support highs in the low
to mid 80`s ahead of the cold front.
Britt
&&
.AVIATION: (For the 06z TAFs through 06z Sunday Night)
Issued at 1052 PM CDT Sat Sep 14 2013
Just VFR mid-high level cloudiness late tgt ahead of an upper
level trough moving sewd through the nrn Plains. Sely sfc winds
will continue late tgt as the large sfc high centered over the
Ohio Valley region moves sewd. A cold front will drop sewd to the
UIN area Sunday aftn. There should be scattered showers and
thunderstorms along this front. Will include prob30 for shra/tsra in
the UIN taf Sunday aftn...and the rest of the taf sites Sunday evng.
Should also see VFR low-mid level cloudiness move into UIN as
well Sunday aftn...and the rest of the taf sites Sunday evng. The
ceiling may eventually drop into the MVFR catagory at UIN and COU
by late Sunday evng. The sfc wind will veer around to a s-swly
direction ahead of the front on Sunday at the taf sites. The wind
will shift to a n-nwly direction by late Sunday aftn in UIN after
fropa...and the rest of the taf sites Sunday evng.
Specifics for KSTL: Increasing high level clouds late tgt...then
mid level clouds moving in on Sunday...and VFR low-mid level
clouds Sunday evng as the cold front drops sewd into the STL area.
Will include prob30 for shra/tsra Sunday ngt in the STL taf. The
cloud ceiling may eventually drop into the MVFR catagory late
Sunday night. A sely sfc wind late tgt will increase to 10-11 kts
on Sunday and veer around to a swly direction. The sfc wind will
shift to a n-nwly direction Sunday evng after fropa.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ELKO NV
1205 PM PDT FRI SEP 13 2013
.SYNOPSIS...ABUNDANT MOISTURE AND INSTABILITY FROM A SLOW MOVING
STORM SYSTEM WILL BRING SCATTERED THUNDERSTORMS AND WIDESPREAD
SHOWERS TO NORTHERN NEVADA. SOME AREAS MAY SEE HEAVY RAIN...WITH
POSSIBLE FLOODING CONCERNS. LOOK FOR SCATTERED THUNDERSTORMS
AGAIN ACROSS EASTERN NEVADA ON SATURDAY. DRY WEATHER RETURNS TO
NEVADA SUNDAY THROUGH NEXT WEEK...WITH BREEZY CONDITIONS MONDAY
INTO TUESDAY.
&&
.UPDATE...UPDATED THE FLASH FLOOD WATCH, REFRESHING THE WORDING,
AND EXTENDING IT TO INCLUDE ELKO AND WHITE PINE COUNTIES INTO
SATURDAY EVENING. THUNDERSTORM COVERAGE WILL BE DECREASED ON
SATURDAY COMPARED TO RECENTLY, BUT WITH A MOIST AIR MASS LINGERING
AND IT BEING THE WEEKEND, FELT IT BEST TO KEEP THE WATCH GOING ONE
MORE DAY.
NEXT ROUND OF THUNDERSTORMS DEVELOPING ON SCHEDULE EARLY THIS
AFTERNOON. MOST STORMS WILL SHOW A NET SOUTH/SE MOTION WHICH MAY
REDUCE THE FLOODING THREAT, AT LEAST COMPARED TO YESTERDAY. TURNER
&&
.PREV DISCUSSION... /ISSUED AT 325 AM /
SYNOPSIS...ABUNDANT MOISTURE AND INSTABILITY FROM A SLOW MOVING
STORM SYSTEM WILL BRING SCATTERED THUNDERSTORMS AND WIDESPREAD
SHOWERS TO NORTHERN NEVADA. SOME AREAS MAY SEE HEAVY RAIN...WITH
POSSIBLE FLOODING CONCERNS. LOOK FOR SCATTERED THUNDERSTORMS
AGAIN ACROSS EASTERN NEVADA ON SATURDAY. DRY WEATHER RETURNS TO
NEVADA SUNDAY THROUGH NEXT WEEK...WITH BREEZY CONDITIONS MONDAY
INTO TUESDAY.
SHORT TERM...TODAY THROUGH SATURDAY. A LARGE COUNTERCLOCKWISE
CIRCULATION CAN BE SEEN OVER NORTHEAST NEVADA THIS MORNING. THIS
IS ASSOCIATED WITH AN UPPER LEVEL STORM SYSTEM THAT HAS BEEN SLOW
TO MOVE OUT OF THE AREA. IT HAS BEEN RESPONSIBLE FOR THE RAINFALL
THE AREA HAS RECEIVED IN THE LAST TWO DAYS. MODELS SHOW IT MOVING
SLOWLY EAST DURING THE DAY TODAY. BUT WE WILL STILL BE UNDER ITS
EFFECTS.
RIGHT NOW...RADAR IS SHOWING SOME WEAK RETURNS WITH LIGHT SHOWERS
OVER PORTIONS OF HUMBOLDT COUNTY...WITH ENHANCED ACTIVITY SEEN IN
SOUTHWEST IDAHO. 3KM HRRR IS SHOWING AN INCREASE IN SHOWER ACTIVITY
BEGINNING IN THE LATE MORNING HOURS OVER ELKO AND WHITE PINE
COUNTIES.
MODELS CONTINUE TO SHOW A FAVORABLE ENVIRONMENT FOR SHOWERS AND
THUNDERSTORMS TO DEVELOP TODAY. CAPE VALUES ARE FORECAST TO BE
AROUND 200-600 J/KG...WITH THE HIGHEST VALUES SEEN IN WHITE PINE
AND ELKO COUNTIES. STORM MOTIONS WILL ONCE AGAIN BE QUITE SLOW AT
ABOUT 5 TO 10 KNOTS IN THE 700-500 MB LAYER. K-VALUES DURING THE
FRIDAY TIME FRAME RANGE FROM 35-40C...WITH CORFIDI VECTOR
MAGNITUDES OF 0-5 KNOTS. BASED ON THE GUIDANCE...WILL CONTINUE THE
FLASH FLOOD WATCH WITH NO CHANGES. POP GRIDS ALSO LOOKED GOOD AND
ONLY MADE MINOR ADJUSTMENTS.
FOR TONIGHT...UPPER LEVEL SYSTEM WILL SLOWLY WORK ITS WAY EAST AND
SET UP SHOP SOMEWHERE AROUND NORTHERN UTAH. THE REGION WILL STILL
BE UNDER A MOIST AND UNSTABLE ATMOSPHERE SO HAVE CONTINUED
ISOLATED THUNDERSTORMS WITH SCATTERED TO NUMEROUS RAIN SHOWERS.
BY SATURDAY...THE FORECAST AREA WILL BE UNDER A NORTHWEST FLOW
ALOFT...WITH SOME MINOR DRYING TAKING PLACE IN THE WESTERN ZONES.
BUT IT SHOULD BE MOIST AND UNSTABLE ENOUGH IN THE
EAST...ELKO...EUREKA...WHITE PINE...AND NORTHEAST NYE
COUNTIES...FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
AFTERNOON HIGHS WILL RUN AT OR JUST ABOVE NORMAL.
LONG TERM...SATURDAY NIGHT THROUGH NEXT THURSDAY. MODELS IN GOOD
AGREEMENT ONLY EXCEPTION IS THE GFS IS A BIT COOLER AND STRONGER
WITH THE TROUGH MOVING ACROSS NORTHERN NEVADA ON TUESDAY AND
WEDNESDAY. ISOLATED THUNDERSTORMS EXPECTED ACROSS NORTHEASTERN
NEVADA ON SUNDAY AFTERNOON AND EVENING AS A UPPER LEVEL TROUGH ALONG
WITH INSTABILITY AND RESIDUAL MOISTURE REMAIN OVER THIS AREA. MUCH
DRIER CONDITIONS THROUGH THE REST OF THE PERIOD...ONLY SIGNIFICANT
WEATHER WILL BE COOLING TEMPERATURES AND BREEZY WINDS EARLY NEXT WEEK AS
A COLD FRONT MOVES THROUGH THE AREA LATE MONDAY INTO TUESDAY MORNING
AND THEN ANOTHER WARM UP BY THURSDAY AHEAD OF A STRONG UPPER LEVEL
SYSTEM. TEMPERATURES WILL BE ABOVE NORMAL SUNDAY THROUGH TUESDAY
BEFORE COOLING TO NEAR NORMAL READINGS BY THE MIDDLE OF NEXT WEEK.
AVIATION...MAINLY VFR CONDITIONS HOWEVER KELY MAY SEE SOME
INTERMITTENT MVFR CIGS AND OTHER TERMINALS MAY TEMPORARILY SEE MVFR
VISIBILITIES DUE TO HEAVIER RAIN SHOWERS. THUNDERSTORMS POSSIBLE AT
ALL TERMINALS WITH 20 PERCENT CHANCE AT KTPH AND KWMC AND 30 TO 40
PERCENT CHANCE AT KELY AND KEKO.
FIRE WEATHER...VERY MOIST AIR MASS OVER THE AREA...COMBINED WITH
INSTABILITY...WILL PROVIDE THE IMPETUS FOR SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF NORTHERN NEVADA. SOME DRYING POSSIBLE
TOMORROW IN THE WESTERN ZONES...BUT SHOULD SEE SCATTERED SHOWERS
AND THUNDERSTORMS IN THE EASTERN FIRE ZONES OF 454 AND 457...AND
WELL AS ALL OF ZONE 455 AND 469 AND 470. EVEN DRIER STILL ON
SUNDAY WITH ONLY ISOLATED COVERAGE IN 469 AND 470. A DRY COLD
FRONTAL PASSAGE EXPECTED MONDAY INTO TUESDAY WHICH WILL BRING
BREEZY CONDITIONS TO NORTHERN NEVADA.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SATURDAY EVENING FOR NORTHERN ELKO
COUNTY...RUBY MOUNTAINS/EAST HUMBOLDT RANGE...SOUTH CENTRAL ELKO
COUNTY...SOUTHEASTERN ELKO COUNTY...SOUTHWESTERN ELKO COUNTY...
WHITE PINE COUNTY.
FLASH FLOOD WATCH UNTIL MIDNIGHT PDT TONIGHT FOR NORTHEASTERN
NYE COUNTY...NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY...
SOUTHERN LANDER COUNTY AND SOUTHERN EUREKA COUNTY.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS ELKO NV
325 AM PDT FRI SEP 13 2013
.SYNOPSIS...ABUNDANT MOISTURE AND INSTABILITY FROM A SLOW MOVING
STORM SYSTEM WILL BRING SCATTERED THUNDERSTORMS AND WIDESPREAD
SHOWERS TO NORTHERN NEVADA. SOME AREAS MAY SEE HEAVY RAIN...WITH
POSSIBLE FLOODING CONCERNS. LOOK FOR SCATTERED THUNDERSTORMS
AGAIN ACROSS EASTERN NEVADA ON SATURDAY. DRY WEATHER RETURNS TO
NEVADA SUNDAY THROUGH NEXT WEEK...WITH BREEZY CONDITIONS MONDAY
INTO TUESDAY.
&&
.SHORT TERM...TODAY THROUGH SATURDAY. A LARGE COUNTERCLOCKWISE
CIRCULATION CAN BE SEEN OVER NORTHEAST NEVADA THIS MORNING. THIS
IS ASSOCIATED WITH AN UPPER LEVEL STORM SYSTEM THAT HAS BEEN SLOW
TO MOVE OUT OF THE AREA. IT HAS BEEN RESPONSIBLE FOR THE RAINFALL
THE AREA HAS RECEIVED IN THE LAST TWO DAYS. MODELS SHOW IT MOVING
SLOWLY EAST DURING THE DAY TODAY. BUT WE WILL STILL BE UNDER ITS
EFFECTS.
RIGHT NOW...RADAR IS SHOWING SOME WEAK RETURNS WITH LIGHT SHOWERS
OVER PORTIONS OF HUMBOLDT COUNTY...WITH ENHANCED ACTIVITY SEEN IN
SOUTHWEST IDAHO. 3KM HRRR IS SHOWING AN INCREASE IN SHOWER ACTIVITY
BEGINNING IN THE LATE MORNING HOURS OVER ELKO AND WHITE PINE
COUNTIES.
MODELS CONTINUE TO SHOW A FAVORABLE ENVIRONMENT FOR SHOWERS AND
THUNDERSTORMS TO DEVELOP TODAY. CAPE VALUES ARE FORECAST TO BE
AROUND 200-600 J/KG...WITH THE HIGHEST VALUES SEEN IN WHITE PINE
AND ELKO COUNTIES. STORM MOTIONS WILL ONCE AGAIN BE QUITE SLOW AT
ABOUT 5 TO 10 KNOTS IN THE 700-500 MB LAYER. K-VALUES DURING THE
FRIDAY TIME FRAME RANGE FROM 35-40C...WITH CORFIDI VECTOR
MAGNITUDES OF 0-5 KNOTS. BASED ON THE GUIDANCE...WILL CONTINUE THE
FLASH FLOOD WATCH WITH NO CHANGES. POP GRIDS ALSO LOOKED GOOD AND
ONLY MADE MINOR ADJUSTMENTS.
FOR TONIGHT...UPPER LEVEL SYSTEM WILL SLOWLY WORK ITS WAY EAST AND
SET UP SHOP SOMEWHERE AROUND NORTHERN UTAH. THE REGION WILL STILL
BE UNDER A MOIST AND UNSTABLE ATMOSPHERE SO HAVE CONTINUED
ISOLATED THUNDERSTORMS WITH SCATTERED TO NUMEROUS RAIN SHOWERS.
BY SATURDAY...THE FORECAST AREA WILL BE UNDER A NORTHWEST FLOW
ALOFT...WITH SOME MINOR DRYING TAKING PLACE IN THE WESTERN ZONES.
BUT IT SHOULD BE MOIST AND UNSTABLE ENOUGH IN THE
EAST...ELKO...EUREKA...WHITE PINE...AND NORTHEAST NYE
COUNTIES...FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
AFTERNOON HIGHS WILL RUN AT OR JUST ABOVE NORMAL.
.LONG TERM...SATURDAY NIGHT THROUGH NEXT THURSDAY. MODELS IN GOOD
AGREEMENT ONLY EXCEPTION IS THE GFS IS A BIT COOLER AND STRONGER
WITH THE TROUGH MOVING ACROSS NORTHERN NEVADA ON TUESDAY AND
WEDNESDAY. ISOLATED THUNDERSTORMS EXPECTED ACROSS NORTHEASTERN
NEVADA ON SUNDAY AFTERNOON AND EVENING AS A UPPER LEVEL TROUGH ALONG
WITH INSTABILITY AND RESIDUAL MOISTURE REMAIN OVER THIS AREA. MUCH
DRIER CONDITIONS THROUGH THE REST OF THE PERIOD...ONLY SIGNIFICANT
WEATHER WILL BE COOLING TEMPERATURES AND BREEZY WINDS EARLY NEXT WEEK AS
A COLD FRONT MOVES THROUGH THE AREA LATE MONDAY INTO TUESDAY MORNING
AND THEN ANOTHER WARM UP BY THURSDAY AHEAD OF A STRONG UPPER LEVEL
SYSTEM. TEMPERATURES WILL BE ABOVE NORMAL SUNDAY THROUGH TUESDAY
BEFORE COOLING TO NEAR NORMAL READINGS BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...MAINLY VFR CONDITIONS HOWEVER KELY MAY SEE SOME
INTERMITTENT MVFR CIGS AND OTHER TERMINALS MAY TEMPORARILY SEE MVFR
VISIBILITIES DUE TO HEAVIER RAIN SHOWERS. THUNDERSTORMS POSSIBLE AT
ALL TERMINALS WITH 20 PERCENT CHANCE AT KTPH AND KWMC AND 30 TO 40
PERCENT CHANCE AT KELY AND KEKO.
&&
.FIRE WEATHER...VERY MOIST AIR MASS OVER THE AREA...COMBINED WITH
INSTABILITY...WILL PROVIDE THE IMPETUS FOR SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF NORTHERN NEVADA. SOME DRYING POSSIBLE
TOMORROW IN THE WESTERN ZONES...BUT SHOULD SEE SCATTERED SHOWERS
AND THUNDERSTORMS IN THE EASTERN FIRE ZONES OF 454 AND 457...AND
WELL AS ALL OF ZONE 455 AND 469 AND 470. EVEN DRIER STILL ON
SUNDAY WITH ONLY ISOLATED COVERAGE IN 469 AND 470. A DRY COLD
FRONTAL PASSAGE EXPECTED MONDAY INTO TUESDAY WHICH WILL BRING
BREEZY CONDITIONS TO NORTHERN NEVADA.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR NORTHEASTERN NYE
COUNTY...NORTHERN ELKO COUNTY...NORTHERN LANDER COUNTY AND
NORTHERN EUREKA COUNTY...RUBY MOUNTAINS/EAST HUMBOLDT RANGE...
SOUTH CENTRAL ELKO COUNTY...SOUTHEASTERN ELKO COUNTY...SOUTHERN
LANDER COUNTY AND SOUTHERN EUREKA COUNTY...SOUTHWESTERN ELKO
COUNTY...WHITE PINE COUNTY.
&&
$$
86/90/90/86
AREA FORECAST DISCUSSION
NWS PORTLAND OR
223 AM PDT SUN SEP 15 2013
.SYNOPSIS...A TROUGH OF LOW PRESSURE WILL MOVE OVER THE PACIFIC NW
TODAY THROUGH TUESDAY...RESULTING IN COOLER AND SHOWERY WEATHER.
THERE MAY BE SOME ISOLATED THUNDERSTORMS EMBEDDED WITHIN THE SHOWERS
TODAY. THE TROUGH WILL DEPART WEDNESDAY AND AN UPPER RIDGE WILL BRING
DRY AND WARMER WEATHER FOR THURSDAY. ANOTHER TROUGH WILL BRING A
RETURN OF RAIN AND COOLER TEMPERATURES FRIDAY.
&&
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...THE PORTLAND FORECAST
AREA IS STILL UNDER A STRONG INVERSION EARLY THIS MORNING WITH THE
UPPER LOW STILL OFFSHORE. LOW CLOUDS AND FOG HAS FILLED IN ALONG THE
COAST OVERNIGHT AND STRATUS IS PUSHING INLAND THIS MORNING. THE LOW
CLOUDS ARE FILLING IN FASTER FROM THE SOUTH TO THE NORTH...BUT SHOULD
COVER MOST OF THE WILLAMETTE VALLEY BY SUNRISE.
THE LOW IS NEARING THE OREGON COAST AND WATER VAPOR IMAGERY SHOWS A
BAND OF MID/UPPER LEVEL MOISTURE JUST OFFSHORE SOUTHERN OREGON.
MOISTURE CIRCULATING AROUND THE INLAND HIGH IS ALSO STREAMING OVER
EXTREME NW OREGON AND SW WASHINGTON AND BE ME AN INDICATION OF WHERE
THE GREATEST POTENTIAL FOR THUNDERSTORMS WILL BE TODAY.
FORECASTING THUNDERSTORM/SHOWER CHANCES AND LOCATION ARE THE GREATEST
SHORT-TERM CHALLENGES THIS MORNING. THERE WAS A LIGHTNING STRIKE NEAR
THE LOW CENTER OVERNIGHT INDICATIVE OF SOME ELEVATED
INSTABILITY...BUT WOULD LIKE TO SEE MORE CONVECTION OFFSHORE BEFORE
INCREASING PROBABILITIES FOR THE PORTLAND FORECAST AREA.
BESIDES SOME DRIZZLE ALONG THE COAST THINK MOST AREAS WILL BE MORE ON
THE DRY SIDE THIS MORNING AND HAVE REDUCED POPS. HAVE ALSO REMOVED
THUNDERSTORMS FOR THE EARLY MORNING AS THE BEST DYNAMICS AND CHANCES
LOOK TO BE THIS AFTERNOON AS THE TROUGH BEGINS TO SHIFT OVER THE
AREA. THE HRRR MODEL WHICH HAS BEEN PERFORMING EXCEPTIONALLY WELL IN
REGARDS TO CONVECTION THIS SEASON SUGGESTS THAT THE BEST CHANCES FOR
SOME ELEVATED SHOWERS AND EMBEDDED THUNDERSTORMS IS DURING THE MID TO
LATE MORNING THROUGH THE AFTERNOON ALONG A BROAD AND NOT
SUPER-REFINED AXIS FROM ASTORIA SOUTH AND EAST TO MT JEFFERSON. THIS
IS WHERE WE ARE IN THE RIGHT ENTRANCE OF THE UPPER JET...HAVE GOOD
DIFFLUENCE ALOFT...AND HAVE IMPRESSIVE MID LEVEL
LAPSE RATES. BE AWARE THAT IF YOU HEAR THUNDER IT MAY CATCH YOU OFF
GUARD AS IT MAY BE WELL ABOVE THE STRATUS DECK.
IN THE AFTERNOON PERIOD...SURFACE/LOWER BASED INSTABILITY INCREASES
IN THE CASCADES AND IS BETTER CO-LOCATED WITH THE DYNAMICS ASSOCIATED
WITH THE TROUGH AXIS/TROPOPAUSE FOLD AS THE UPPER TROUGH SHIFTS
NORTH. SO AT THIS TIME ELEVATED SHOWERS AND EMBEDDED THUNDERSTORMS
LOOK TO REMAIN POSSIBLE ALONG THE NORTHERN TIER OF THE AREA...WITH
ADDITIONAL SHOWERS AND THUNDERSTORMS FORMING ALONG THE CASCADES AND
EAST OF THE CWA INTO CENTRAL OREGON IN PLACES THAT GET SOME HEATING.
OTHERWISE COOLER TEMPERATURES CAN BE EXPECTED TODAY AND CONTINUING
THROUGH TUESDAY AS THE UPPER TROUGH LINGERS OVER THE AREA.A WEAK
COLD FRONT WILL MOVE ACROSS THE AREA LATE TONIGHT AND MONDAY AND
CONTINUE THE CHANCES FOR RAIN. THERE MAY BE A BRIEF BREAK IN THE RAIN
MONDAY NIGHT BEFORE A SHORTWAVE TROUGH BRINGS ADDITIONAL SHOWERS TO
THE AREA TUESDAY. THE TROUGH AXIS SHOULD PUSH EAST OF THE AREA
TUESDAY NIGHT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY NIGHT...AN UPPER RIDGE WILL
BUILD WEDNESDAY BEHIND THE DEPARTING TROUGH. THE RIDGE WILL AMPLIFY
THURSDAY AS ANOTHER UPPER LEVEL LOW DEVELOPS OFFSHORE...RESULTING IN
DRY AND WARMER CONDITIONS. MODELS ARE IN FAIRLY GOOD AGREEMENT THAT
THE LOW WILL SWING A COLD FRONT THROUGH THE REGION FRIDAY. THIS LOW
WILL LINGER OVER THE AREA SATURDAY...FOR SLIGHTLY BELOW NORMAL
TEMPERATURES AND A CONTINUING CHANCE FOR RAIN. TH/BURGESS
&&
.AVIATION...LOW LEVEL WINDS ALONG THE COAST HAVE TURNED TO THE SW
THIS MORNING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS IS
RESULTING IN IFR OR LOWER CONDITIONS FOR THE COASTAL TAF
SITES IN LOW STRATUS...FOG...AND PATCHY DRIZZLE. A SOUTHERLY SURGE
OF MARINE MOISTURE IS ALSO PUSHING INLAND UP THE WILLAMETTE
VALLEY. CURRENT SATELLITE IMAGERY SHOWS THE STRATUS UP INTO THE
CENTRAL VALLEY AND EXPECT IT TO CONTINUE NORTH INTO THE PORTLAND
METRO AREA IN THE NEXT COUPLE OF HOURS. SOME ELEVATED SHOWER OR
THUNDERSHOWER ACTIVITY IS POSSIBLE TODAY...ESPECIALLY BETWEEN 15Z AND
21Z. CIGS MAY LIFT A BIT THIS AFTERNOON...BUT EXPECT MVFR
CONDITIONS INLAND AND IFR AT THE COAST TO PERSIST THROUGH MOST OF
THE DAY. THERE MAY BE SOME BRIEF PERIODS OF VFR WITH ANY SHOWER
ACTIVITY DUE TO MIXING OF THE LOW LEVEL AIR MASS. CIGS WILL LOWER
AGAIN THIS EVENING AS SW LOW LEVEL FLOW CONTINUES.
KPDX AND APPROACHES...VFR CONDITIONS SHOULD GIVE WAY TO MVFR
STRATUS AROUND 11Z TO 12Z THIS MORNING. THERE IS A 30 TO 50 PERCENT
CHANCE A THUNDERSTORM WILL IMPACT THE TERMINAL BETWEEN 15Z AND 21Z
SUNDAY. CIGS MAY LIFT A BIT THIS AFTERNOON...BUT MOSTLY MVFR
CONDITIONS TO PERSIST THROUGH TODAY. CIGS WILL LOWER AGAIN THIS
EVENING. PYLE
&&
.MARINE...FLOW WILL TURN SW THIS MORNING OVER THE WATERS AS A LOW
PRESSURE SYSTEM APPROACHES THE COAST. THIS LOW WILL BRING THE
CHANCE FOR SOME SCATTERED THUNDERSTORM ACTIVITY TODAY. OTHERWISE
EXPECT LITTLE IMPACT FROM THE SYSTEM. CONDITIONS SHOULD REMAIN
RATHER BENIGN FOR THE NEXT SEVERAL DAYS...WITH WINDS GENERALLY
BELOW 20 KT AND SEAS BELOW 6 FT.
ANOTHER WEAK SYSTEM WILL ARRIVE ON TUE...WITH LITTLE IMPACT OTHER
THAN AGAIN TURNING THE WINDS BRIEFLY TO THE SW. THE NEXT
POTENTIALLY SIGNIFICANT MARINE IMPACTS LOOK TO ARRIVE LATE NEXT
WEEK INTO NEXT WEEKEND. A MORE ACTIVE WEATHER PATTERN WILL
ARRIVE AS A SHARP UPPER LEVEL TROUGH APPROACHES THE PAC NW. SMALL
CRAFT ADVISORIES WILL LIKELY BE NECESSARY WITH A CHANCE FOR GALES
AND SEAS OVER 10 FT AT SOME POINT. CONFIDENCE ON TIMING REMAINS
LOW THIS FAR OUT...BUT CONFIDENCE IS INCREASING ON THE OVERALL
PATTERN. PYLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
REST OF THE FORECAST DISCUSSION UNCHANGED...ONSHORE WINDS AND STRONG
COOLING ALOFT WILL BRING COOLER TEMPS BEGINNING SUN AND CONTINUING
THROUGH TUE. UPPER TROUGH EXPECTED TO LINGER OVER THE REGION SUN
NIGHT THROUGH TUE...SO IT WILL BE DIFFICULT TO RULE OUT ANY PERIODS
FROM THE THREAT OF SHOWERS. A WEAK SHORTWAVE LATE SUN NIGHT AND MON
MORNING PROVIDES A BIT BETTER OF A CHANCE FOR SHOWERS...THEN A
STRONGER SHORTWAVE TUE WILL BRING BACK BETTER CHANCES FOR SHOWERS.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...UPPER TROUGH MOVES
EAST OF THE AREA LATE TUESDAY INTO EARLY WEDNESDAY...WITH UPPER
RIDGING BUILDING IN WEDNESDAY EVENING. THE UPPER RIDGE AMPLIFIES
OVER THE PACNW ON THURSDAY IN RESPONSE TO A DEVELOPING LOW AND
ASSOCIATED TROUGH OFFSHORE. MODELS ARE IN FAIRLY GOOD AGREEMENT THAT
THURSDAY WILL BE SUNNY AND WARM...BEFORE THE AFOREMENTIONED LOW
SWINGS A COOL FRONT THROUGH THE REGION FRIDAY. THIS LOW WILL LINGER
OVER THE AREA SATURDAY...FOR SLIGHTLY BELOW NORMAL TEMPERATURES AND
A CONTINUING CHANCE FOR RAIN. BURGESS
&&
.AVIATION...A MIX OF IFR AND MVFR CONDITIONS ALONG THE COAST WILL
LIKELY CONTINUE THROUGH SUNDAY. IFR TO MVFR CONDITIONS CURRENTLY
ACROSS THE SOUTHERN HALF OF THE WILLAMETTE VALLEY WILL TURN VFR
SHORTLY.A STRONG SOUTHWEST PUSH LATE TONIGHT SHOULD ALLOW MVFR CIGS
TO SPREAD NORTHWARD UP THE WILLAMETTE VALLEY BETWEEN 06Z AND 15Z
SUNDAY. ELEVATED THUNDER BECOMES POSSIBLE AS EARLY AS 09Z AND WILL
FORM WELL ABOVE THE STRATUS LAYER. HOWEVER...BETTER CHANCES WILL BE
AS THE UPPER LEVEL WAVE SLIDES NORTH ALONG THE COAST. DON`T HAVE
ENOUGH CONFIDENCE TO SPECIFICALLY INCLUDE FOR KONP KEUG KSLE AND
KAST YET BUT IT SEEMS LIKE EVERYTHING IS COMING TOGETHER FOR THE
KPDX KTTD AND KHIO AREA BEGINNING AROUND 17Z. EXPECT THE PRIMARY
THUNDER THREAT WILL LAST A FEW HOURS BEFORE EVOLVING INTO SCATTERED
SHOWER ACTIVITY. MAIN CHALLENGE WILL BE IF THERE IS STRATUS ACROSS
THE NORTH WITH THE THUNDER ABOVE OR IF THE STRATUS WILL BE RAPIDLY
MIXED OUT UNDER THE LEADING EDGE OF SHOWER ACTIVITY EARLIER. NAM AND
GFS DIFFER ON THIS AND PRELIMINARILY DECIDED TO FOLLOW THE GFS FOR
THE 06Z PACKAGE.
KPDX AND APPROACHES...VFR CONDITIONS SHOULD GIVE WAY TO MVFR
CONDITIONS AROUND 12Z SUNDAY...WHICH WILL LIKELY PERSIST WELL INTO
SUNDAY. THERE IS A 30 TO 50 PERCENT CHANCE A THUNDERSTORM WILL
IMPACT THE TERMINAL BETWEEN 15Z AND 21Z SUNDAY. JBONK/NEUMAN
&&
.MARINE...ONLY CHANGE WAS TO NUDGE UP THE WIND WAVES AND SWELL BY
ABOUT A FOOT. THIS BETTER MATCHES OBS NOW AND IS CLOSER TO ENP
FORECASTS FOR THE NEXT 18 HOURS. PREVIOUS DISCUSSION FOLLOWS. /JBONK
BENIGN CONDITIONS TO REMAIN OVER THE WATERS INTO EARLY NEXT WEEK.
WINDS SHOULD REMAIN GENERALLY BELOW 20 KT...WITH SEAS BELOW 6 FT.
THERE WILL BE A CHANCE FOR THUNDERSTORMS OVER THE WATERS LATE
TONIGHT AND SUNDAY AS AN UPPER LEVEL SYSTEM PASSES OVERHEAD.
A MORE ACTIVE WEATHER PATTERN WILL ARRIVE LATE NEXT
WEEK...SPECIFICALLY THURSDAY THROUGH SATURDAY. SMALL CRAFT ADVISORIES
WILL LIKELY BE NECESSARY WITH A CHANCE FOR GALES AND SEAS OVER 10 FT
AT SOME POINT DEPENDING UPON THE TRACK OF DEVELOPING LOW PRESSURES.
HOWEVER...MODELS HAVE VARIED WIDELY FROM RUN TO RUN...AND GIVEN THE
TIME OF YEAR...KEPT WINDS AND SEAS AT MORE MODEST LEVELS. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1210 AM MDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 1207 AM MDT SUN SEP 15 2013
EXTENDED FLASH FLOOD WATCH OVER THE SOUTHERN LARAMIE RANGE AND
NEARBY FOOTHILLS THROUGH THIS AFTERNOON. CANCELLED THE SNOWY RANGE
WATCH. MAIN CHANCE FOR FLOODING RAIN SHOULD BE THIS AFTERNOON. MORE
DETAILS WILL BE PROVIDED WITH THE MORNING AREA FROECAST DISCUSSION.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 315 PM MDT SAT SEP 14 2013
CURRENT KCYS RADAR LOOP SHOWS SHOWERS AND TSTORMS DEVELOPING
ACROSS THE MOUNTAINS AND SLOWLY MOVING EAST/NORTH EAST ACROSS
SOUTHEAST WYOMING. RADAR PRECIP ESTIMATES ALREADY SHOWING A FEW
AREAS OF RAINFALL RATES ABOVE ONE INCH PER HOUR. A FLASH FLOOD
WATCH WILL CONTINUE THROUGH LATE THIS EVENING. THE UPPER LEVEL LOW
WHICH RESULTED IN THE WIDESPREAD FLOODING ACROSS THE SOUTHWEST AND
THE FRONT RANGE WILL WEAKEN TONIGHT AND PUSH EAST INTO COLORADO.
IN ADDITION...A COOL FRONT WILL MOVE ACROSS EASTERN WYOMING AND
NEBRASKA LATE THIS AFTERNOON AND THROUGH LATE THIS EVENING.
UPSLOPE FLOW COMBINED WITH INSTABILITY AND MOISTURE WILL LIKELY
KEEP THE TSTORM ACTIVITY GOING FOR A WHILE TONIGHT BEFORE THE
PRECIP BECOMES MORE STRATIFORM IN NATURE LATE. MODELS SHOW QUITE A
BIT OF QPF ALONG THE FRONT RANGE...EXTENDING INTO SOUTHEAST
WYOMING. THE 12Z NAM AND GEM SHOW OVER AN INCH OF ADDITIONAL
RAINFALL ALONG THE LARAMIE RANGE INCLUDING THE ADJACENT HIGH
VALLEYS OF ALBANY COUNTY AND HIGH PLAINS OF PLATTE/LARAMIE COUNTY.
INCREASED POP IN THESE AREAS TONIGHT AND INTO SUNDAY MORNING.
HOWEVER...THERE IS STILL UNCERTAINTY WITH HOW MUCH RAIN WILL FALL.
GFS AND ECMWF SHOW AROUND A THIRD TO HALF AN INCH OF RAINFALL WITH
THIS FEATURE...SO ONLY KEPT THE FLASH FLOOD WATCH GOING UNTIL
MIDNIGHT TONIGHT. WILL LET THE EVENING AND MIDNIGHT SHIFT DECIDE
IF IT NEEDS TO BE EXTENDED THROUGH SUNDAY. CURRENT THINKING IS THE
RAINFALL WILL BE MORE LIGHT TO MODERATE IN INTENSITY. PATCHY DENSE
FOG IS LIKELY TO DEVELOP ONCE AGAIN TONIGHT DUE TO THE MOIST
UPSLOPE FLOW...ESPECIALLY ACROSS SOUTHEAST WYOMING.
FOR SUNDAY...ANOTHER COOL DAY IS EXPECTED BEHIND THE COOL FRONT WITH
TEMPERATURES RETURNING TO THE UPPER 50S TO UPPER 60S. IT WILL BE
MORE STABLE ON SUNDAY...SO DO NOT EXPECT AS MUCH HEAVY RAINFALL.
LIGHT TO MODERATE RAIN AND DRIZZLE APPEARS LIKELY ALONG AND WEST OF
THE LARAMIE RANGE THROUGH SUNDAY EVENING...AND MAY EVEN LINGER
NEAR THE SOUTHERN LARAMIE RANGE INTO EARLY MONDAY MORNING.
THE WEAKENING UPPER LEVEL TROUGH WILL MOVE ACROSS SOUTHEAST
WYOMING AND EASTERN COLORADO EARLY ON MONDAY. SOMEWHAT DRIER AIR
WILL BEGIN TO MOVE INTO THE REGION DURING THE DAY WITH HIGH
TEMPERATURES RETURNING TO THE 70S. CAN NOT RULE OUT WIDELY
SCATTERED SHOWERS AND TSTORMS OVER SOUTHEAST WYOMING DURING THE
AFTERNOON DUE TO INSTABILITY AND LINGERING MOISTURE. INCREASED POP
BETWEEN 20 TO 40 PERCENT...HIGHEST AROUND THE LARAMIE RANGE. A
SHORTWAVE RIDGE WILL MOVE INTO THE FORECAST AREA MONDAY
NIGHT...RESULTING IN DRIER CONDITIONS AND POP BELOW 5 PERCENT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 242 PM MDT SAT SEP 14 2013
FINALLY...WARMER AND DRIER WEATHER WILL BE IN TAP FOR THE CWA
THROUGH THE EARLY PART OF NEXT WEEKEND. A SHORTWAVE TROUGH EXITS
THE REGION BY 12Z TUESDAY AND IS REPLACED BY A DRIER SOUTHWEST
WIND FLOW FOR TUESDAY AND INTO TUESDAY NIGHT. A LARGER AMPLITUDE
SHORTWAVE TROUGH...CURRENTLY NEAR 50N AND 145W...WILL MOVE EAST
AND ACROSS THE CWA WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. MODELS
DIFFER ON AMPLITUDE AND TIMING OF THE FEATURE WITH THE GFS FASTER
AND WITH LESS AMPLITUDE THAN THE OTHER MEDIUM RANGE MODELS. THE
ASSOCIATED SURFACE COLD FRONT MOVES ACROSS THE CWA WEDNESDAY
AFTERNOON. WESTERLY WINDS WILL GUST AS HIGH AS 40 MPH AHEAD AND
THEN BEHIND THE FRONT WEDNESDAY AND WEDNESDAY EVENING. GUSTY WINDS
MAY ALSO OCCUR THROUGH THURSDAY ON THE BACKSIDE OF THE NEWLY
FORMED NORTHERN PLAINS CLOSED MID LEVEL LOW. TEMPERATURES WILL ALSO
COOL BEHIND THE FRONT WITH 60S TO MID 70S COMMON FOR DAYTIME HIGHS
ACROSS THE LOWER ELEVATIONS THURSDAY AND POSSIBLY FRIDAY. THE
TEMPERATURES SHOULD WARM SOME FOR NEXT SATURDAY.
POPS WILL BE THE QUESTION OVER THE CWA WEDNESDAY AND THURSDAY AND
POSSIBLY AGAIN NEXT SATURDAY. THE 12Z ECMWF IS TRENDING FURTHER
SOUTH WITH THE CLOSED MID LEVEL LOW FOR THURSDAY AND PAINTS MORE
QPF THAN ITS PREVIOUS RUN AS WELL AS THE GFS. MOST POPS WILL BE
OVER AND NEAR THE MOUNTAINS ON WEDNESDAY AND THURSDAY...BUT THE
POSSIBLE CYCLONIC FLOW ALOFT MAY PRODUCE MORE SHOWERS OVER THE CWA
ON THOSE DAYS. HAVE BUMPED UP POPS A BIT OVER THE CWA FOR WEDNESDAY
AND THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1050 PM MDT SAT SEP 14 2013
LATEST HRRR GUIDANCE SHOWING A WIDEPSREAD IFR/LIFR EVENT TAKING
SHAPE AS A COLD FRONT PUSHES SOUTH INTO NORTHERN COLORADO.
NORTHEAST UPSLOPING WINDS WILL PERSIST MOST OF THE NEXT 24-36
HOURS AND BRING DOWN CEILINGS AT AIRPORTS EAST OF THE LARAMIE
RANGE SHORTLY AFTER 08Z AT CHADRON...THEN SPREADING QUICKLY SOUTH
AND SOUTHWEST. WE COULD STAY DOWN ALL DAY SUNDAY AND MAYBE GO TO
MVFR DURING THE AFTERNOON. WITH UPSLOPING WINDS AND COOL
TEMPERATURES...DO EXPECT IFR/LIFR TO RETURN SUNDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 227 PM MDT SAT SEP 14 2013
NO FIRE WEATHER CONCERNS THROUGH NEXT WEEK. MOIST CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND WITH AFTERNOON HUMIDITY VALUES
GENERALLY ABOVE 50 PERCENT. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH SOME OF THE
SHOWERS PRODUCING LOCALLY HEAVY RAIN. A FRONT WILL MOVE ACROSS THE
AREA TONIGHT WITH MOIST UPSLOPE WINDS ON SUNDAY AND NUMEROUS RAIN
SHOWERS. WARMER AND DRIER CONDITIONS ARE EXPECTED ACROSS THE
REGION BY THE MIDDLE PART OF NEXT WEEK...WITH DAYTIME HUMIDITIES
BETWEEN 25 TO 40 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR WYZ116-117.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...TJT
LONG TERM...WEILAND
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1054 PM MDT SAT SEP 14 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 315 PM MDT SAT SEP 14 2013
CURRENT KCYS RADAR LOOP SHOWS SHOWERS AND TSTORMS DEVELOPING
ACROSS THE MOUNTAINS AND SLOWLY MOVING EAST/NORTH EAST ACROSS
SOUTHEAST WYOMING. RADAR PRECIP ESTIMATES ALREADY SHOWING A FEW
AREAS OF RAINFALL RATES ABOVE ONE INCH PER HOUR. A FLASH FLOOD
WATCH WILL CONTINUE THROUGH LATE THIS EVENING. THE UPPER LEVEL LOW
WHICH RESULTED IN THE WIDESPREAD FLOODING ACROSS THE SOUTHWEST AND
THE FRONT RANGE WILL WEAKEN TONIGHT AND PUSH EAST INTO COLORADO.
IN ADDITION...A COOL FRONT WILL MOVE ACROSS EASTERN WYOMING AND
NEBRASKA LATE THIS AFTERNOON AND THROUGH LATE THIS EVENING.
UPSLOPE FLOW COMBINED WITH INSTABILITY AND MOISTURE WILL LIKELY
KEEP THE TSTORM ACTIVITY GOING FOR A WHILE TONIGHT BEFORE THE
PRECIP BECOMES MORE STRATIFORM IN NATURE LATE. MODELS SHOW QUITE A
BIT OF QPF ALONG THE FRONT RANGE...EXTENDING INTO SOUTHEAST
WYOMING. THE 12Z NAM AND GEM SHOW OVER AN INCH OF ADDITIONAL
RAINFALL ALONG THE LARAMIE RANGE INCLUDING THE ADJACENT HIGH
VALLEYS OF ALBANY COUNTY AND HIGH PLAINS OF PLATTE/LARAMIE COUNTY.
INCREASED POP IN THESE AREAS TONIGHT AND INTO SUNDAY MORNING.
HOWEVER...THERE IS STILL UNCERTAINTY WITH HOW MUCH RAIN WILL FALL.
GFS AND ECMWF SHOW AROUND A THIRD TO HALF AN INCH OF RAINFALL WITH
THIS FEATURE...SO ONLY KEPT THE FLASH FLOOD WATCH GOING UNTIL
MIDNIGHT TONIGHT. WILL LET THE EVENING AND MIDNIGHT SHIFT DECIDE
IF IT NEEDS TO BE EXTENDED THROUGH SUNDAY. CURRENT THINKING IS THE
RAINFALL WILL BE MORE LIGHT TO MODERATE IN INTENSITY. PATCHY DENSE
FOG IS LIKELY TO DEVELOP ONCE AGAIN TONIGHT DUE TO THE MOIST
UPSLOPE FLOW...ESPECIALLY ACROSS SOUTHEAST WYOMING.
FOR SUNDAY...ANOTHER COOL DAY IS EXPECTED BEHIND THE COOL FRONT WITH
TEMPERATURES RETURNING TO THE UPPER 50S TO UPPER 60S. IT WILL BE
MORE STABLE ON SUNDAY...SO DO NOT EXPECT AS MUCH HEAVY RAINFALL.
LIGHT TO MODERATE RAIN AND DRIZZLE APPEARS LIKELY ALONG AND WEST OF
THE LARAMIE RANGE THROUGH SUNDAY EVENING...AND MAY EVEN LINGER
NEAR THE SOUTHERN LARAMIE RANGE INTO EARLY MONDAY MORNING.
THE WEAKENING UPPER LEVEL TROUGH WILL MOVE ACROSS SOUTHEAST
WYOMING AND EASTERN COLORADO EARLY ON MONDAY. SOMEWHAT DRIER AIR
WILL BEGIN TO MOVE INTO THE REGION DURING THE DAY WITH HIGH
TEMPERATURES RETURNING TO THE 70S. CAN NOT RULE OUT WIDELY
SCATTERED SHOWERS AND TSTORMS OVER SOUTHEAST WYOMING DURING THE
AFTERNOON DUE TO INSTABILITY AND LINGERING MOISTURE. INCREASED POP
BETWEEN 20 TO 40 PERCENT...HIGHEST AROUND THE LARAMIE RANGE. A
SHORTWAVE RIDGE WILL MOVE INTO THE FORECAST AREA MONDAY
NIGHT...RESULTING IN DRIER CONDITIONS AND POP BELOW 5 PERCENT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 242 PM MDT SAT SEP 14 2013
FINALLY...WARMER AND DRIER WEATHER WILL BE IN TAP FOR THE CWA
THROUGH THE EARLY PART OF NEXT WEEKEND. A SHORTWAVE TROUGH EXITS
THE REGION BY 12Z TUESDAY AND IS REPLACED BY A DRIER SOUTHWEST
WIND FLOW FOR TUESDAY AND INTO TUESDAY NIGHT. A LARGER AMPLITUDE
SHORTWAVE TROUGH...CURRENTLY NEAR 50N AND 145W...WILL MOVE EAST
AND ACROSS THE CWA WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. MODELS
DIFFER ON AMPLITUDE AND TIMING OF THE FEATURE WITH THE GFS FASTER
AND WITH LESS AMPLITUDE THAN THE OTHER MEDIUM RANGE MODELS. THE
ASSOCIATED SURFACE COLD FRONT MOVES ACROSS THE CWA WEDNESDAY
AFTERNOON. WESTERLY WINDS WILL GUST AS HIGH AS 40 MPH AHEAD AND
THEN BEHIND THE FRONT WEDNESDAY AND WEDNESDAY EVENING. GUSTY WINDS
MAY ALSO OCCUR THROUGH THURSDAY ON THE BACKSIDE OF THE NEWLY
FORMED NORTHERN PLAINS CLOSED MID LEVEL LOW. TEMPERATURES WILL ALSO
COOL BEHIND THE FRONT WITH 60S TO MID 70S COMMON FOR DAYTIME HIGHS
ACROSS THE LOWER ELEVATIONS THURSDAY AND POSSIBLY FRIDAY. THE
TEMPERATURES SHOULD WARM SOME FOR NEXT SATURDAY.
POPS WILL BE THE QUESTION OVER THE CWA WEDNESDAY AND THURSDAY AND
POSSIBLY AGAIN NEXT SATURDAY. THE 12Z ECMWF IS TRENDING FURTHER
SOUTH WITH THE CLOSED MID LEVEL LOW FOR THURSDAY AND PAINTS MORE
QPF THAN ITS PREVIOUS RUN AS WELL AS THE GFS. MOST POPS WILL BE
OVER AND NEAR THE MOUNTAINS ON WEDNESDAY AND THURSDAY...BUT THE
POSSIBLE CYCLONIC FLOW ALOFT MAY PRODUCE MORE SHOWERS OVER THE CWA
ON THOSE DAYS. HAVE BUMPED UP POPS A BIT OVER THE CWA FOR WEDNESDAY
AND THURSDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1050 PM MDT SAT SEP 14 2013
LATEST HRRR GUIDANCE SHOWING A WIDEPSREAD IFR/LIFR EVENT TAKING
SHAPE AS A COLD FRONT PUSHES SOUTH INTO NORTHERN COLORADO.
NORTHEAST UPSLOPING WINDS WILL PERSIST MOST OF THE NEXT 24-36
HOURS AND BRING DOWN CEILINGS AT AIRPORTS EAST OF THE LARAMIE
RANGE SHORTLY AFTER 08Z AT CHADRON...THEN SPREADING QUICKLY SOUTH
AND SOUTHWEST. WE COULD STAY DOWN ALL DAY SUNDAY AND MAYBE GO TO
MVFR DURING THE AFTERNOON. WITH UPSLOPING WINDS AND COOL
TEMPERATURES...DO EXPECT IFR/LIFR TO RETURN SUNDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 227 PM MDT SAT SEP 14 2013
NO FIRE WEATHER CONCERNS THROUGH NEXT WEEK. MOIST CONDITIONS WILL
CONTINUE THROUGH THE WEEKEND WITH AFTERNOON HUMIDITY VALUES
GENERALLY ABOVE 50 PERCENT. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH SOME OF THE
SHOWERS PRODUCING LOCALLY HEAVY RAIN. A FRONT WILL MOVE ACROSS THE
AREA TONIGHT WITH MOIST UPSLOPE WINDS ON SUNDAY AND NUMEROUS RAIN
SHOWERS. WARMER AND DRIER CONDITIONS ARE EXPECTED ACROSS THE
REGION BY THE MIDDLE PART OF NEXT WEEK...WITH DAYTIME HUMIDITIES
BETWEEN 25 TO 40 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR WYZ114-116-117.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...WEILAND
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
258 AM PDT SUN SEP 15 2013
.SYNOPSIS...
DRY CONDITIONS WITH NEAR NORMAL TEMPERATURES FOR THE NEXT FEW DAYS.
&&
.DISCUSSION...
UPPER LOW CENTER IS FINALLY MOVING OUT OF NV AND HAVE REMOVED ANY
CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE SIERRA FOR THIS
AFTERNOON AS DRIER CONDITIONS ARE EXPECTED. THE UPPER RIDGE OVER
THE REGION WILL SLOWLY SLIDE EAST AS A LOW PRESSURE CENTER OFF THE
NORCAL COAST WILL LIFT NE INTO THE PAC NW THIS EVENING. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL SKIRT THE REGION ACCORDING TO
THE RUC MODEL LATER TODAY. INCREASING WINDS OVER THE WEST SIDE OF
THE SJV AND THROUGH THE COTTONWOOD AND PACHECO PASS ARE A CONCERN
BUT ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. A BIT OF A
COOL DOWN IS EXPECTED FOR MONDAYS HIGHS AS THE MARINE COOLED AIR
WILL HAVE AN INFLUENCE ON VALLEY TEMPS.
ZONAL FLOW SETS UP MONDAY AND OPENS THE DOORS FOR CONTINUED SEASONAL
TEMPS AS ANOTHER SHORT WAVE MOVES THROUGH ON TUESDAY WITH RE-ENFORCING
COOL TEMPS FOR TUESDAY AND WED. SOME MINOR UPPER LEVEL SHORTWAVE
RIDGING IS EXPECTED ON THURSDAY AND FRIDAY IN ADVANCE OF A STRONG
UPPER LEVEL TROUGH OF OF LOW PRESSURE THAT IS EXPECTED TO SWEEP
THROUGH THE REGION ON FRI NIGHT. THE GFS IS WEAKER WITH THE SYSTEM
AND H500 FALLS ARE NOT AS DRASTIC AS PREVIOUS RUNS. WE HAVE BUMPED
UP TEMPS A FEW DEGREES OVER THE WEEKEND AS THE GUIDANCE IS LEANING
MORE TOWARDS CLIMO IN THE EXTENDED...HOWEVER WE ARE STILL EXPECTING
BELOW TEMPERATURES NEXT WEEKEND.
&&
.AVIATION...
MVFR CONDITIONS DUE TO SMOKE WILL PERSIST NEAR YOSEMITE NATIONAL
PARK...OTHERWISE VFR CONDITIONS WILL PREVAIL ELSEWHERE IN THE
CENTRAL CALIFORNIA INTERIOR DURING THE NEXT 24 HOURS.
&&
.AIR QUALITY ISSUES...
SAN JOAQUIN VALLEY...NONE.
TUOLUMNE COUNTY...AIR QUALITY ALERT THROUGH MONDAY SEPTEMBER 16TH.
SEE SFOAQAHNX.
FOR ADDITIONAL INFORMATION...CALL THE TUOLUMNE COUNTY AIR DISTRICT
OFFICE AT 209.533.5693
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS HIGH.
THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 09-15 104:1983 74:1982 72:1938 45:1970
KFAT 09-16 105:1937 70:1908 73:1934 49:1955
KFAT 09-17 105:1979 73:1950 74:1984 48:1965
KBFL 09-15 106:1979 75:1959 77:1979 40:1915
KBFL 09-16 109:1929 74:1959 77:1971 42:1915
KBFL 09-17 108:1913 74:1993 76:1979 45:1915
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...JDB
AVN/FW...DCH
SYNOPSIS...JDB
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
925 AM MDT SUN SEP 15 2013
.UPDATE...
&&
.SHORT TERM...RAIN SHOWERS HAVE BEEN RAPIDLY DEVELOPING OVER THE
FOOTHILLS AND PLAINS DURING THE PAST SEVERAL HOURS. PLATTEVILLE
PROFILER SHOWING WEAK UPSLOPE FLOW FROM THE NORTHEAST HAS BEEN
DEEPENING OVER THE PAST SEVERAL HOURS TO MOUNTAIN TOP LEVEL. THE
WEAK FRONTAL BOUNDARY IS FINALLY BEGINNING TO PUSH SOUTH AND
SOUTHWEST AND JUST MOVING INTO THE FRONT RANGE AREA. FORECASTS
LOOK IN GOOD SHAPE FOR NOW.
.AVIATION...CEILINGS LOWERING AND WILL CONTINUE TO LOWER FROM THE
NORTH TO IFR CONDITIONS IN THE NEXT FEW HOURS AS RAIN BEGINS TO
SPREAD ACROSS THE AREA FROM THE NORTH AND NORTHEAST. RAINFALL
SHOULD BE DIMINISHING THIS EVENING WITH IMPROVING CONDITIONS.
POSSIBLE FOG LATER TONIGHT.
&&
.HYDROLOGY...RAIN DEVELOPING AND WILL BECOME MORE WIDESPREAD BY
LATER THIS MORNING OVER THE ENTIRE AREA...WITH HIGHER COVERAGE
OVER THE FOOTHILLS AND ADJACENT PLAINS. CURRENT RAINFALL OVER
LARIMER COUNTY GAUGES SHOWING RAINFALL RATES GENERALLY FROM .20 TO
.50 OF AN INCH PER HOUR WITH THE HEAVIER SHOWERS. JUST ISSUED AN
AREAL FLOOD WARNING FOR MUCH OF THE FRONT RANGE FOOTHILLS...AND
ADJACENT PLAINS AND STRETCHING NORTHEAST TO COVER AREAS ALONG THE
SOUTH PLATTE UP THROUGH JULESBURG AND AREAS ALONG THE CACHE LA
POUDRE. STILL COULD SEE 1 TO 2 INCHES OF ADDITIONAL RAINFALL
THROUGH THIS EVENING ESPECIALLY IN THE FOOTHILLS.
&&
.PREV DISCUSSION... /ISSUED 338 AM MDT SUN SEP 15 2013/
SHORT TERM...REMNANTS OF WK UPPER LEVEL TROUGH WILL SHEAR ACROSS THE
AREA THRU TONIGHT WITH SOME MINOR MID LVL ASCENT. MEANWHILE LOW
LVL WINDS ARE CURRENTLY NLY ALONG THE FNT RANGE BUT ARE FCST TO
BECOME MORE NELY LATER THIS MORNING INTO THE AFTN HOURS BEHIND A
COOL FNT. THIS SHOULD ALLOW FOR INCREASING PCPN IN THE NRN
FOOTHILLS AND MTNS EAST OF THE DIVIDE THIS MORNING WHICH WILL
SPREAD SOUTHWARD THRU THE DAY. AT THIS TIME HIGHEST PCPN AMOUNTS
SHOULD FOCUS IN AND NR THE FOOTHILLS AND IN THE MTNS EAST OF THE
DIVIDE. THE GFS AND HRRR SHOW POTENTIAL RAINFALL AMOUNTS RANGING
FROM 1 TO 2 INCHES OVER THE HIGHER TERRAIN WHILE THE ECMWF KEEPS
THE HEAVIER AMOUNTS FOCUSED EAST OF THE HIGHER TERRAIN OVER THE
FRONT RANGE URBAN CORRIDOR THRU THIS AFTN. AT THIS POINT WILL KEEP
THE HEAVIER AMOUNTS OVER THE HIGHER TERRAIN.
MEANWHILE WITH CONSIDERABLE CLOUD COVER THERE WILL BE LIMITED
INSTABILITY SO THE PCPN WILL BE MORE OF A STRATIFORM EVENT WITH
RAINFALL RATES MAINLY AROUND ONE QUARTER INCH PER HOUR. WILL KEEP
FFA IN PLACE HOWEVER BIGGWST CONCERNS WOULD BE CONSIDERABLE AMOUNT
OF ROCK AND MUD SLIDE ACTIVITY DUE TO EXTREMELY SATURATED GROUND.
HIGH THIS AFTERNOON OVER NERN CO MAY NOT GET MUCH ABV 60 EXCEPT OVER
THE FAR NERN CORNER WHERE HIGHS MAY GET CLOSE TO 70.
FOR TONIGHT THERE WILL BE SOME LINGERING RAIN THEU EVENING WHICH
WILL GRADUALLY END FM NORTH TO SOUTH OVERNIGHT. TEMPS MAY BE COLD
ENOUGH FOR SOME SNOW OVER THE HIGHER MTNS ABV 11000 FT BEFORE PCPN
ENDS.
LONG TERM...MODELS SHOW THE WEAK UPPER TROUGH TO MOVE ACROSS THE
FORECAST AREA ON MONDAY...THEN UPPER RIDGING IS PROGGED INTO
TUESDAY AFTERNOON. SOUTHWESTERLY FLOW ALOFT MOVES IN TUESDAY
NIGHT...WITH AN UPPER TROUGH GETTING INTO THE NORTHERN GREAT BASIN
BY 12Z WEDNESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA MONDAY THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER PRESSURE AND WIND FIELDS SHOW SOUTHEASTERLIES
OVER THE PLAINS ON MONDAY...THEN NORMAL DIURNAL PATTERNS KICK IN
MONDAY NIGHT INTO TUESDAY. LOW LEVEL TROUGHING AND DOWNSLOPING ARE
BOTH PROGGED LATER TUESDAY INTO TUESDAY NIGHT. CONCERNING MOISTURE
..MONDAY DRIES OUT SOMEWHAT...WITH FURTHER DRYING ON TUESDAY.
PRECIPITABLE WATER VALUES ARE IN THE 0.75-0.85 INCH RANGE OVER THE
WESTERN PLAINS MONDAY...DRYING INTO THE 0.50 TO 0.75 INCH RANGE
BY LATER TUESDAY. VALUES ARE HIGHER OVER THE EASTERN PLAINS ON
MONDAY...BUT DRY TO SIMILAR VALUES BY LATER TUESDAY. THE BOUNDARY
LAYER DEW POINTS ARE PROGGED IN THE LOWER TO MID 50S F OVER THE
PLAINS MONDAY INTO TUESDAY MONRING...THEN THEY DECREASE INTO THE
40S TO LOWER 50S F LATER TUESDAY AND TUESDAY NIGHT. VALUES ARE IN
THE MID 30S TO MID 40S OVER THE MOUNTAINS ALL FOUR PERIODS. THERE
IS SOME CAPE AROUND BOTH LATE DAY MONDAY AND LATE DAY TUESDAY...
BUT NOTHING SIGNIFICANT. THE QPF FIELDS HAVE LIMITED MEASURABLE
RAINFALL AMOUNTS MONDAY...NOTHING MONDAY NIGHT OR TUESDAY MONRING
..THEN A TAD LATE DAY TUESDAY IN THE MOUNTAINS. SO FOR POPS...
20-40%S IN THE MOUNTAINS LATE DAY MONDAY AND LATE DAY TUESDAY. FOR
THE PLAINS...10-20%S LATE DAY MONDAY...NONE TUESDAY. FOR
TEMPERATURES...MONDAY`S HIGHS ARE 3-7 C WARMER THAN TODAY`S.
TUESDAY`S HIGHS ARE 1-4 C WARMER THAN MONDAY`S. FOR THE LATER DAYS
..WEDNESDAY THROUGH SATURDAY...MODELS BRING AN UPPER TROUGH ACROSS
THE CWA WEDNESDAY AFTERNOON INTO EARLY THURSDAY...ALONG WITH AN
ACCOMPANYING COLD FRONT. AFTER THAT...UPPER RIDGING MOVES IN
THROUGH SATURDAY. MOISTURE IS LIMITED AND TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
AVIATION...CEILINGS SHOULD GRADUALLY DROP INTO THE IFR CATEGORY LATER
THIS MORNING WITH AREAS OF RAIN DEVELOPING. THIS ACTIVITY WILL
CONTINUE THRU THE AFTN BEFORE ENDING DURING THE EVENING HOURS.
OVERNIGHT LOW CEILINGS AND SOME FOG WILL BE POSSIBLE THRU MON
MORNING.
HYDROLOGY...WILL CONTINUE WITH THE FLASH FLOOD WATCH THROUGH 6 PM
THIS EVENING. AREAS OF RAIN WILL INCREASE THROUGH THE MORNING
HOURS AND CONTINUE THROUGH THE AFTERNOON IN THE MOUNTAINS AND
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDER. RAINFALL
AMOUNTS OVER THE HIGHER TERRAIN THROUGH 6 PM MAY RANGE FROM 1 TO 2
INCHES WITH ONE HALF INCH TO ONE INCH AT LOWER ELEVATIONS. COULD
SEE A FEW LOCALIZED AREAS OF FLASH FLOODING HOWEVER BIGGEST
CONCERN WILL BE AN INCREASE IN ROCK AND MUD SLIDES IN THE
FOOTHILLS AND MOUNTAINS DUE TO EXTREMELY SATURATED GROUND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
.RIVER FLOOD WARNINGS CONTINUE ALONG THE CACHE LA POUDRE...BIG
THOMPSON...AND SOUTH PLATTE RIVER OUT THROUGH JULESBURG.
.AREAL FLOOD WARNINGS UNTIL 9 PM THIS EVENING FOR COZ035..036..
038>041..043>045..048>50.
.FLASH FLOOD WATCH UNTIL 6 PM MDT THIS EVENING FOR COZ033>036-
038>041-043.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RJK
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1108 AM EDT Sun Sep 15 2013
.NEAR TERM [Through Tonight]...
The previous forecast remains on track with generally isolated to
scattered convection expected this afternoon and into early this
evening with easterly low level flow and a very weak front in the
area. The 700-500 mb lapse rates on the morning sounding were
somewhat steep around 6.2 C/km, and there is some mid-level dry air
present, so it would not be shocking to see a stronger storm or two
this afternoon, but nothing widespread is expected. Our 11z local
hi-res ARW run did have some decent updraft velocities with some
of the convection this afternoon. Only minor changes were made to
the PoP grid for today to account for the latest 11z local ARW and
the 12z HRRR trends, and scattered convection was also extended
through 03z tonight based on the hi-res guidance with a rapid
decrease after that.
&&
.SHORT TERM [Monday Through Monday Night]...
Through the early part of the week, the tri-state area will be
under the influence of a narrow east-west oriented ridge aloft. At
the surface, high pressure will persist along the eastern
seaboard, with Ingrid approaching the Mexican coast by Monday.
This combination will keep a decent easterly fetch in place across
the region. The east to southeast low-level flow should gradually
moisten the atmosphere and allow for slightly better coverage of
afternoon and evening convection, especially over the eastern
third of the forecast area. However, given the upper ridge in
place, forecast PoPs will remain at or below 30 percent through
Tuesday. The warm temperatures will continue with highs in the
lower 90s expected each day.
&&
.LONG TERM [Tuesday through Saturday]...
An upper level ridge is expected to dominate during the first half
of the period with surface ridging northeast of the area. This
should provide easterly surface flow with fairly low PoPs in the
20-30% range through most of the week. By late in the period, the
ridging may start to break down with a slight increase in moisture
leading to 30-40% PoPs. Near seasonal temperatures are expected.
&&
.AVIATION...
[Through 12z Monday] Low clouds have cleared out of all of the TAF
sites this morning with the exception of KABY, and they should
clear out of there between 15-16z. Otherwise, VFR conditions will
prevail through the remainder of the day with isolated to
scattered convection expected this afternoon.
&&
.MARINE...
East to southeast winds will slowly increase over the coastal
waters through mid-week as the region remains situated between
high pressure over the Mid-Atlantic states and Hurricane Ingrid
near the Mexican coast. Winds may approach exercise caution levels
by late Tuesday or Wednesday. Seas will increase by tonight as
long period swells from Ingrid reach the western marine zones.
Seas will likely rise to around 4 ft Monday afternoon with some 5
foot seas possible by mid-week.
&&
.FIRE WEATHER...
Relative humidity levels will remain above critical thresholds,
with dispersions remaining within acceptable levels. No fire
weather hazards anticipated.
&&
.HYDROLOGY...
Downward water level trends will continue for the next several
days as neither significant nor widespread rainfall is
anticipated.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 92 71 92 71 92 / 40 20 30 20 30
Panama City 90 75 90 75 91 / 30 30 20 20 20
Dothan 91 70 91 71 91 / 30 30 20 10 20
Albany 90 71 92 69 91 / 30 30 20 10 20
Valdosta 91 70 92 70 90 / 30 20 30 20 30
Cross City 92 69 91 70 90 / 40 20 30 20 30
Apalachicola 88 76 87 75 89 / 30 20 20 20 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
Near Term/Long Term/Aviation...DVD
Short Term/Marine/Hydrology...Camp
Fire Weather...Harrigan
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
957 AM EDT SUN SEP 15 2013
.SYNOPSIS...
ISSUED AT 527 AM EDT SUN SEP 15 2013
HIGH PRESSURE WILL GIVE WAY TO A FAST MOVING UPPER LEVEL
DISTURBANCE LATER TODAY. THIS SYSTEM WILL BRING SOME RAINFALL BY
MID AFTERNOON...ESPECIALLY ALONG AND WEST OF A KNOX TO COLDWATER
LINE. THE RAIN WILL THEN CONTINUE TO SPREAD EASTWARD INTO THE
EVENING HOURS. THE RAIN IS EXPECTED TO TAPER THROUGH THE
OVERNIGHT HOURS. IT WILL REMAIN COOLER THAN NORMAL TODAY...WITH
HIGHS IN THE MID 60S ACROSS SOUTHERN LOWER MICHIGAN TO THE LOWER
70S INTO NORTHWEST INDIANA. LOWS TONIGHT WILL DIP INTO THE UPPER
40S NORTH TO LOWER 50S SOUTH.
&&
.UPDATE...
ISSUED AT 919 AM EDT SUN SEP 15 2013
A FEW ADJUSTMENTS MADE TO CURRENT FORECAST TO SLOW DOWN ARRIVAL OF
MEASURABLE PRECIP INTO EARLY AFTERNOON AND BACK OFF A FEW DEGREES
ON AFTERNOON HIGHS ACROSS THE N/NW AREAS.
RADAR SHOWS RATHER IMPRESSIVE COVERAGE OF RAIN/RAINSHOWERS MOVING
INTO NW PARTS OF THE AREA AT PRESENT. HOWEVER...SFC OBS DEPICT A
DIFFERENT STORY WITH SOME SPRINKLES/LGT RAIN REACHING THE GROUND
WITH HIGH CLOUD BASES. 12Z SOUNDINGS FROM ILX...DTX AND DVN ALL
PAINTED THE PICTURE OF A LOT OF DRY AIR TO OVERCOME YET BELOW 700
MB (ROUGHLY 10000 FT). RAP SOUNDINGS AND LOOK AT PAST FEW RUNS OF
HRRR ALL SEEM TO POINT TOWARDS NOT A WHOLE LOT THIS MORNING BUT
IMPROVING CHANCES FOR MEASURABLE RAINFALL THIS AFTERNOON. QUICK
GLANCE AT OBS OUT OF BENTON HARBOR SHOW THAT LIGHT RAIN IS NOW
FALLING WITH A HUNDREDTH OF AN INCH RECORDED WITH NO CIG BELOW
12000 FT. HAVE ADJUSTED TRENDS SOMEWHAT TO KEEP SOME SLGT CHC/CHC
POPS IN FAR NW/N AREAS BUT SLOWED ARRIVAL OF STEADIER PRECIP UNTIL
MID TO LATE AFTERNOON. MAIN WINDOW OF RAINFALL (RATES MAYBE A
TENTH OF AN INCH OR MORE PER HOUR) WOULD APPEAR TO ARRIVE CLOSER
TO 22Z AND CONTINUE INTO EVENING (02 TO 03Z).
IN TERMS OF TEMPS...WITH NO INDICATIONS OF CLOUD COVER ACROSS THE
NORTH ERODING/MIXING IN ANY FASHION THROUGH THE DAY HAVE LOWERED
TEMPS A FEW DEGREES IN THE NORTH TO LOW-MID 60S AT BEST. WILL
LEAVE SOUTHERN AREAS NEAR 70 WITH FILTERED SUNSHINE LIKELY TO HELP
WITH SOME WARMING AS PCPN HOLDS OFF UNTIL LATER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EDT SUN SEP 15 2013
ROBUST/EFFICACIOUS SHORTWAVE ENERGY TO SHARPEN NORTHERN QUEBEC TO
SOUTHWESTERN GREAT LAKES TROF BY THIS EVENING. WALL OF COPIOUS
UPSTREAM MOISTURE WITH STEAM OF 8-11 G/KG 1000-850 MB RIVER
ALONG/WEST OF 95W...WITH MONSOONAL SOURCED MOISTURE FURTHER WEST
WITH SUPPLYING 200 PERCENT OF NORMAL PWAT THROUGHOUT CENTRAL
ROCKIES/GREAT BASIN. ANTECEDENT CONDS TO EAST HOWEVER QUITE
CONTRASTING WITH YDAY POST FRONTAL MIXOUT TO LOWER/MID 30S SFC
DEWPOINTS...STILL LANGUISHING IN THE LOWER 40S. FURTHERMORE DEARTH
OF MOISTURE THROUGH MIDLVS AT PRESENT WITH PLUME OF 30C PLUS 7-5H
LAYER DEWPOINT DIFFERENTIALS. THIS SHOULD HOLD UPSTREAM PRECIP AT
BAY FOR MOST OF THE DAY FAR ERN/SERN CWA. EJECTION OF LEAD SHORTWAVE
ACROSS IA TO SERN WI THIS AM...LARGELY SHUNTING RAFL TO W-NW OF
REGION WITH PRIMARY FOCUS ALONG NOSE OF 8H JETLET IMPINGING INTO
CENTRAL IA. NERN PERIPHERY OF THIS FEATURE SHIFTS INTO NORTHERN IL
BY LATE AM AND WEAKENS IN DEFERENCE TO SIGNIFICANTLY STRONGER ENERGY
WITHIN UPSTREAM. GIVEN DERISION OF SUBCLOUD CONDENSATION PRESSURE
DEFICITS WOULD ONLY ANTICIPATE SOME SPOTTY LIGHT RAFL POSSIBLE NWRN
CWA. THEREAFTER...INCREASE IN MIDLEVEL DEFORMATION ABOVE 925-8H
FRONTOGENESIS FROM FAR SWRN MI/NWRN IN/NRN IL INTO SCNTL IA...SHOULD
LEAD TO INCREASE IN SHRA CONVERGE. TOP/DOWN SATURATION TO GREATLY
SQUELCH DESTABILIZATION /MUCAPE AOB 250 J/KG WITH NEAR NIL CHANCES
FOR TSRA THIS AFTN. THEREAFTER...SHUNT OF WARM FRONT SWD INTO LOWER
OH VALLEY WITH MIDLVL TROF/60-70 KT JET AXIS PUSHING INTO LWR GREAT
LAKES BY AROUND 03 UTC...WITH ALL FOCUSES FOR SUBSTANTIVE LIFT
DIVERTING...WITH ONLY LIGHT SPOTTY RAFL AND SIG LOWERING OF POPS
REMAINDER OF TONIGHT. SLIGHT GRADIENT ADJUSTMENT TO TEMPS TODAY WITH
UPWARD NUDGE IN SWRN CWA WITH NERN FRINGE OF THERMAL RIDGE LAPPING
NEARBY...AND DOWNWARD HOLD ACRS NWRN/NRN CWA IN THICKER CLOUD
COVER/SLIGHT NEGATIVE 925MB THERMAL ADVECTION. AGAIN SLIGHT GRADIENT
ENHANCEMENT TONIGHT WITH STRONGER PULL OF COLD/DEEPER NERLY FLOW
ACROSS NORTHERN CWA. SOME UNCERTAINTY WITH RESPECT TO CLOUD
COVERAGE/CIGS LATE TONIGHT IN GUID...THOUGH HAVE TRENDED TOWARD
GREATER CLOUD COVER WITH ORPHANED LOW LEVEL MOISTURE PRESENT AMID
WELL MIXED/COOLING MIXED LAYER LIKELY TO MAINTAIN LOW STRATUS
THROUGH DAYBREAK MON.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 527 AM EDT SUN SEP 15 2013
CHILLY CANADIAN AIR WILL CONTINUE TO SPREAD OVER THE AREA MONDAY AS
HIGH PRESSURE DRIFTS ACROSS SOUTHEAST CANADA. GIVEN THE SUBSIDENCE
INVERSION AND MOISTURE TRAPPED BENEATH THE BASE OF THE INVERSION...
ANY EARLY DAY CLEARING SHOULD QUICKLY FILL BACK IN WITH CLOUDS...
MAKING FOR AN OVERALL CLOUDY TO MOSTLY CLOUDY AND COOL DAY. SO HAVE
LOWERED HIGHS A LITTLE MONDAY...MORE IN LINE WITH THE COOLER GFS/MAV.
CLOUDS SHOULD DISSIPATE MONDAY EVENING AND ALLOW OVERNIGHT LOWS TO
FALL WELL DOWN INTO THE 40S...ESPECIALLY OVER NORTHEAST AREAS.
AGAIN...FAVORED THE COOLER MAV. AS FOR THE MIDDLE OF THE WEEK...
FAVORED MORE OF A GFS ENSEMBLE BLEND/MEAN. THE ECMWF CONTINUES TO
HAVE MAJOR RUN TO RUN CONSISTENCY ISSUES RESOLVING THE MASS FIELDS
DOWNSTREAM OF THE WESTERN CONUS RIDGE. THE GFS ENSEMBLE MEAN APPEARS
TO BE THE BEST TO HANDLE THIS SCENARIO...HELPING TO DAMPEN OUT
OUTLIER SOLUTIONS AND FAVORING A MORE ACTIVE PATTERN WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT. ACCORDINGLY...HAVE RAISED SHOWER/THUNDERSTORM
CHANCES THURSDAY NIGHT AND FRIDAY...AND HAVE INTRODUCED A CHANCE FOR
SHOWERS FRIDAY NIGHT GIVEN THE GFS TREND TOWARD A SLOWER SOLUTION.
IN FURTHER SUPPORT...THE GFS ENSEMBLE MEAN MOS HAS TRENDED HIGHER
RAIN CHANCES WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. AS FOR
THUNDERSTORMS/SEVERE STORM POTENTIAL...FAVORABLE MOISTURE SHOULD BE
AVAILABLE FOR STORMS...BUT WEAK BULK SHEAR AND LIMITED CAPE SHOULD
KEEP CHANCES FOR SEVERE STORMS RATHER REMOTE. KEPT FCST PERSISTENCE
WITH CHANCES FOR STORMS WEDNESDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 702 AM EDT SUN SEP 15 2013
ONLY SLIGHT VARIANCE FROM 06 UTC TAFS. CONTINUE TO SUSPECT EROSION
ALONG LEADING EDGE OF RAFL FOR MUCH OF TODAY. OUTSIDE OF A FEW
SPRINKLES MIDDAY INTO KSBN EXPECT THE PRIMARY REFOCUS OF LIFT
TO HOLD UNTIL LATE AFTERNOON/EVENING THAT WILL PROVIDE THE BULK OF
LIGHT RAIN FOR NRN INDIANA TAF SITES. CONCERN CONTS FOR LOWERING
CIGS LATE IN FORECAST PD. GIVEN MOISTER SUB 825MB PROFILE AT KFWA
HAVE INTRODUCED TEMPO FUEL ALT CONDITIONS LATE IN FORECAST
PD...THOUGH REMAIN MORE OPTIMISTIC AT KSBN GIVEN GREATER
SUBSIDENCE/LOWER BLYR RH.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...MURPHY
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...MURPHY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1010 AM CDT Sun Sep 15 2013
...Update to synopsis...
.SYNOPSIS...
ISSUED AT 1010 AM CDT SUN SEP 15 2013
The 15.12Z raob map showed southwesterly wind vectors with magnitudes
in the 35-40 kt over Kansas. @ 500 hPa, an elongated trof was located
across the northeast Pacific. Shortwave ridging was noted across the
northern Rockies. Another broad ridge stretched across the Deep South.
@ 700 hPa and 850 hPa, some drying was noted at KDDC. The pwat was down
to 1.30", which, statistically speaking, is still fairly high for this
time of year. 850 hPa also showed more warming with observed at 21C.
At the sfc, a frontal boundary was analyzed across western Kansas. In
the tropics, Hurricane Ingrid was located at 22.5N 95.8W @ 15.15Z. Invest
94L 950 miles southwest of the Azores. Tropical Storm Manuel was
at 18.5N 103.9W @ 15.15Z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper Midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 700 AM CDT SUN SEP 15 2013
A cold front will move across western Kansas today and should extend
from southeast Kansas to the central Texas Panhandle by Monday
morning. Southwest winds 10 to 15 knots will become north to
northeast at 10 to 15 knots following passage of the cold front.
Local visibilities 4-5 miles in mist can be expected around sunrise
today. Scattered clouds AOA 100 will prevail this morning, and
scattered cumulus clouds with bases near 060 will develop by late
morning. Ceilings 015 to 025 will spread southward behind the cold
front, reaching HYS around 1700Z and GCK and DDC after 0000Z.
Scattered thunderstorms will form along the front around 21Z near
DDC and move east. Upslope flow in eastern Colorado will favor
development of showers and thunderstorms that will weaken and
propagate into western Kansas this evening, reaching GCK around
0500Z and DDC and HYS after 0700Z.
Moist east to northeast upslope flow and stratus with bases 010-020
will persist Monday. An upper level trough will move from the
Rockies to western Kansas Monday and will provide enough upward
vertical motion to support scattered showers and a few
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 58 73 63 / 30 40 40 30
GCK 81 57 72 61 / 20 30 40 30
EHA 84 57 78 62 / 30 30 40 40
LBL 86 58 77 62 / 30 30 40 40
HYS 76 57 71 62 / 20 30 30 40
P28 91 62 79 66 / 40 60 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Ruthi
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
702 AM CDT Sun Sep 15 2013
...Updated Aviation Section...
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 700 AM CDT SUN SEP 15 2013
A cold front will move across western Kansas today and should extend
from southeast Kansas to the central Texas Panhandle by Monday
morning. Southwest winds 10 to 15 knots will become north to
northeast at 10 to 15 knots following passage of the cold front.
Local visibilities 4-5 miles in mist can be expected around sunrise
today. Scattered clouds AOA 100 will prevail this morning, and
scattered cumulus clouds with bases near 060 will develop by late
morning. Ceilings 015 to 025 will spread southward behind the cold
front, reaching HYS around 1700Z and GCK and DDC after 0000Z.
Scattered thunderstorms will form along the front around 21Z near
DDC and move east. Upslope flow in eastern Colorado will favor
development of showers and thunderstorms that will weaken and
propagate into western Kansas this evening, reaching GCK around
0500Z and DDC and HYS after 0700Z.
Moist east to northeast upslope flow and stratus with bases 010-020
will persist Monday. An upper level trough will move from the
Rockies to western Kansas Monday and will provide enough upward
vertical motion to support scattered showers and a few
thunderstorms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 58 73 63 / 30 40 40 30
GCK 81 57 72 61 / 20 30 40 30
EHA 84 57 78 62 / 30 30 40 40
LBL 86 58 77 62 / 30 30 40 40
HYS 76 57 71 62 / 20 30 30 40
P28 91 62 79 66 / 40 60 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Ruthi
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 AM EDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EDT SUN SEP 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE NRN ROCKIES
AND A TROUGH OVER HUDSON BAY RESULTING IN CYCLONIC WNW FLOW THROUGH
THE NRN GREAT LAKES. A SHORTWAVE TROUGH OVER MN AND AREA OF UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 250-300 MB JET OVER NRN
ONTARIO SUPPORTED A LARGE AREA OF RAIN FROM SE MN THROUGH UPPER MI
AND WI. THE STRONGEST 700-500 MB QVECTOR CONV AND HEAVIER PCPN
REMAINED TO THE SOUTH OVER WI. HOWEVER...300K-305K ISENTROPIC LIFT
EXTENDING INTO UPPER MI AHEAD OF THE SFC TROUGH FROM NW IA INTO NW
WI HAS HELPED BRING LIGHT RAIN THROUGH THE CWA. WINDS HAD VEERED
SHARPLY TO THE NE AND INCREASED TO 15 TO 25 KNOTS OVER NRN LAKE
SUPERIOR BEHIND A COLD FRONT SAGGING INTO UPPER MI.
TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE SHORTWAVE AND
AREA OF WIDESPREAD RAIN WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST
AND END BY AFTERNOON. HOWEVER...THE CYCLONIC NNE FLOW AND 850 MB
TEMPS FALLING INTO THE 2C TO 4C RANGE BEFORE THE DEEPER MOISTURE
DEPARTS WILL SUPPORT SOME LAKE ENHANCED RAIN/DRIZZLE INTO N CNTRL
UPPER MI ESPECIALLY OVER THE HIGHER TERRAIN WHERE LOW LEVEL UPSLOPE
FLOW IS STRONGEST. ONCE THE DEEP MOISTURE QUICKLY MOVES OUT AROUND
18Z...THE REMAINING PCPN SHOULD END ALONG WITH DIMINISHING CLOUD
COVER.
TONIGHT...HIGH PRESSURE OVER NRN MANITOBA WHERE SOME TEMPS HAVE
FALLEN INTO THE MID AND UPPER 20S...WILL BUILD INTO UPPER MI
BRINGING CLEARING SKIES AND DIMINISHING WINDS. WITH PWAT VALUES
FALLING CLOSE TO 0.3 INCHES...FAVORABLE RADIATIONAL COOLING WILL
ALLOW TEMPS TO DROP INTO THE LOWER 30S OVER MUCH OF THE INTERIOR
WEST HALF OF UPPER MI WHERE A FROST ADVISORY WAS ISSUED. FARTHER
EAST...LINGERING NE WINDS WILL BE STRONG ENOUGH TO KEEP TEMPS FROM
DROPPING OFF AS MUCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM EDT SUN SEP 15 2013
500MB RIDGE AND SFC PRESSURE WILL CONTROL THE FIRST PORTION OF THE
LONG TERM FORECAST PERIOD. THIS RIDGE WILL MOVE FROM THE NORTHERN
PLAINS ON MONDAY MORNING INTO THE OHIO VALLEY BY TUESDAY NIGHT.
EXPECT UPPER MICHIGAN WEATHER TO BE QUITE PLEASANT MONDAY AND
TUESDAY. ON MONDAY 850MB TEMPS WILL DIP TO AROUND 3-5C...AND WINDS
WILL BE NORTHERLY OFF LAKE SUPERIOR. KEPT HIGHS IN THE UPPER 50S AND
60S ACCORDINGLY. TUESDAY 850MB TEMPS WILL CLIMB TO THE 6-10C RANGE
AND SFC WINDS WILL SWING TO THE SOUTH...RAISING AFTERNOON HIGHS INTO
THE UPPER 60S AND LOW 70S...WHICH IS NORMAL FOR THIS TIME OF YEAR.
MEANWHILE...A DEEP 500MB LOW PRESSURE TROUGH MAKES ITS WAY ONSHORE
OVER THE NORTHWESTERN UNITED STATES. THE ASSOCIATED SFC LOW DEVELOPS
OVER MONTANA BY TUESDAY AFTERNOON...AND STRONG MOISTURE
TRANSPORT BRINGS PWATS UP TO 160 PERCENT OF NORMAL INTO WESTERN
UPPER MICHIGAN BY 06Z WEDNESDAY. AS THE LOW MOVES EASTWARD INTO THE
DAKOTAS THROUGH WEDNESDAY NIGHT...EXPECT THIS AREA OF STRONGER
MOISTURE ADVECTION TO MOVE EASTWARD THROUGH THE CWA. WITH A WEAK
SHORTWAVE FLATTENING THE EXITING RIDGE...AND AREA OF MOISTURE
ADVECTION FEEL THAT CHANCE TO SLIGHT CHANCE POPS ARE WARRANTED
ACROSS UPPER MICHIGAN FOR TUESDAY NIGHT AND WEDNESDAY-WITH HIGHER
POPS LOCATED FURTHER SOUTH NEAR THE BETTER FORCING. THE BEST
INSTABILITY ARRIVES LATER WEDNESDAY MORNING INTO THE AFTERNOON...SO
LEFT THUNDER OUT UNTIL THESE TIMES.
THURSDAY INTO SUNDAY WE DEAL WITH THE ARRIVAL OF THE ACTUAL
SFC/UPPER LEVEL LOW PRESSURE SYSTEM...WHICH MODELS CURRENTLY HAVE
TRAVERSING ACROSS THE UPPER GREAT LAKES. AS USUAL...MODEL
DIFFERENCES WILL GREATLY IMPACT THE FORECAST FOR THE WEEKEND...WITH
THE ECMWF/GEM BRINGING A CUT OFF 500MB LOW ACROSS NORTHEASTERN
MINNESOTA/NORTHERN ONTARIO BY FRIDAY AFTERNOON. THE GFS HAS A
NEUTRALLY TILTED TROUGH REACHING MINNESOTA AROUND THE SAME
TIME...WITH THE SURFACE LOW OVER ONTARIO JUST SOUTH OF JAMES BAY.
DESPITE DIFFERENCES...CAN AGREE THAT THIS WILL LIKELY BE A SOGGY END
TO THE WEEK...WITH MODELS PROJECTING PWATS 160-210 PERCENT OF
NORMAL. NOT GOING TO GET CUTE WITH THE GRIDS AT THIS POINT...BUT
WILL USE THE WPC DAY 3-7 FRONTS/PRESSURE LOCATIONS AS A GUIDE UNTIL
GREATER CONSISTENCY IS ACHIEVED. THIS PUTS THE SFC LOW DIRECTLY OVER
UPPER MICHIGAN ON FRIDAY MORNING...AND OVER QUEBEC BY SATURDAY
AFTERNOON.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 737 AM EDT SUN SEP 15 2013
SIMILAR TO UPSTREAM TRENDS AT CMX...THE PASSAGE OF A COLD FRONT N-S
THIS MORNING WILL BRING A SHARP WSHFT TO THE NNE AT SAW/IWD AND BRING
IFR CIGS AS A SHALLOW COLD WEDGE FOLLOWS THIS FROPA IN THE PRESENCE
OF SOME -SHRA. EXPECT THE LOWEST IFR CIGS AT SAW/IWD WHERE THE N WIND
PRESENTS THE GREATEST UPSLOPE COMPONENT. EXPECT A GRADUAL TRANSITION
TO VFR CONDITIONS IN THE AFTERNOON WITH THE APPROACH OF HIGH PRESSURE
AND THE ARRIVAL OF DRIER AIR. A STEADY NORTH WIND WILL DIMINISH BY THIS
EVENING WITH THE CLOSER APPROACH OF THE HIGH AND LOSS OF OF DAYTIME
HEATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 515 AM EDT SUN SEP 15 2013
NE WINDS UP TO 30 KNOTS TODAY ARE EXPECTED BEHIND A COLD FRONT
MOVING THROUGH LAKE SUPERIOR EARLY THIS MORNING. WINDS WILL DIMINISH
LATE THIS AFTERNOON AND TONIGHT AS HIGH PRESSURE BUILDS INTO THE
AREA. WITH THE HIGH DOMINATING THE REGION MON...WINDS WILL REMAIN
BELOW 20 KNOTS. AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO
20 KNOTS ARE EXPECTED FROM TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 9 AM EDT /8 AM CDT/
MONDAY FOR MIZ002-004-005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1015 AM CDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 1015 AM CDT SUN SEP 15 2013
THE FORECAST WAS UPDATED THROUGH THIS EVENING TO REFLECT THE
LATEST CLOUD COVER AND WIND TRENDS. I INCREASED CLOUD COVER TODAY
TO HAVE THE CLOUDS CLEARING MUCH SLOWER THAN THE PREVIOUS
FORECAST. THE LATEST HRRR AND RAP13 RUNS INDICATE THE CLOUDS WILL
TAKE A WHILE TO CLEAR...WITH THE COOL NORTHERLY FLOW AND LOW
CONVECTIVE TEMPERATURES BOLSTERING THE CLOUD COVER UNTIL MID TO
LATE AFTERNOON.
I GAVE THE SOUTH SHORE OF WISCONSIN LOW CHANCES OF RAIN SHOWERS
DUE TO THE STRONG NE WINDS OFF LAKE SUPERIOR THROUGH EARLY THIS
AFTERNOON.
I WILL LOOK MORE INTO THE THREAT OF FROST AND FREEZING
TEMPERATURES TONIGHT THIS AFTERNOON.
UPDATE ISSUED AT 645 AM CDT SUN SEP 15 2013
UPDATED FOR AVIATION DISCUSSION.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
A COLD FRONT WILL PUSH ACROSS THE NORTHLAND THIS MORNING...EXITING
TO THE SOUTH BY THE AFTERNOON. LINGERING SPRINKLES/AREAS OF DRIZZLE
AND GUSTY NORTHEAST WINDS WILL ACCOMPANY THE FRONTAL PASSAGE THIS
MORNING. HIGH PRESSURE WILL BUILD INTO THE THE NORTHLAND FROM CANADA
THROUGH THE AFTERNOON...BRINGING GRADUALLY CLEARING SKIES AND
DIMINISHING WIND GUSTS. THE HIGH PRESSURE WILL SETTLE OVER THE
WESTERN LAKE SUPERIOR REGION TONIGHT...ALLOWING FOR CALM WINDS CLEAR
SKIES AND STRONG RADIATIONAL COOLING. LATEST MOS GUIDANCE CONTINUES
TO SHOW MOST LOCATIONS IN THE NORTHLAND SEE LOWS IN THE 30-35 DEGREE
RANGE TONIGHT. LOCALLY COOLER READINGS WILL BE FOUND ACROSS THE
IRON RANGE AS WELL AS IN THE HIGHER TERRAIN OF THE MINNESOTA
ARROWHEAD. WARMER READINGS OF 35-40 DEGREES WILL PREVAIL NEAR
LAKE SUPERIOR...AS WELL AS IN THE BRAINERD LAKES AREA. A FROST
ADVISORY FOR THE OVERNIGHT PERIOD WILL BE ISSUED WITH THE MORNING
FORECAST PACKAGE FOR ALL OF THE DLH ZONES EXCEPT CASS AND CROW
WING COUNTIES. THERE IS A POTENTIAL THAT THE FAR NORTHERN ZONES
WILL NEED TO BE UPGRADED TO A FREEZE WARNING IF DEW POINTS FALL
FAR ENOUGH WITH AFTERNOON MIXING TO ALLOW TEMPERATURES TO REACH
THE MID-UPPER 20S FOR A FEW HOURS OVERNIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
QUIET WEATHER CONDITIONS TO START THE EXTENDED PERIOD AS HIGH
PRESSURE OVER THE GREAT LAKES AND AN UPPER RIDGE OVER THE MIDWEST
KEEP SKIES MOSTLY CLEAR AND THE WX DRY. LOW TEMPS TUE MORNING WILL
BE COOL...INTO THE MID 30S TO MID 40S...BUT QUICKLY WARM INTO THE
UPPER 60S AND LOWER 70S UNDER A WAA REGIME AND MOSTLY SUNNY SKIES
THROUGH TUESDAY. STRONG MIXING WILL ALLOW WINDS TO BECOME GUSTY IN
THE AFTERNOON...UP TO 20-25 MPH AT TIMES. AN UPPER TROUGH AND
ASSOCIATED SFC TROUGH/WARM FRONT WILL TRANSLATE E/NEWD ACROSS THE
NRN/CONTROL PLAINS TUE AFTERNOON AND MOVE INTO SRN AND CNTRL MN BY TUE
EVENING. THIS SYSTEM WILL INCREASE CLOUD COVER FROM SOUTH TO NORTH
DURING THE DAY...AND EVENTUALLY BRING IN CHANCES FOR RAIN SHOWERS
AND THUNDERSTORMS TUE NIGHT. THERE STILL EXIST SOME UNCERTAINTY WITH
THE TRACK OF THE SFC LOW AND THE TIMING OF A SECONDARY UPPER S/W
EXPECTED TO DRIVE EWD FROM MT THROUGH ND AND INTO NRN MN SOME TIME
BETWEEN WED AFTERNOON AND EARLY FRI MORNING. COULD SEE A WARM
SECTOR...POSSIBLY CAPPED...DEVELOP WED AFTERNOON PRIOR TO THE
PASSAGE OF AN EWD PROGRESSING COLD FRONT. SO...KEPT WITH LOWER CHC
POPS WED...AND AN INCREASE WED NIGHT THROUGH THUR EVENING. WHICH
WILL ALSO BE THE MOST FAVORABLE TIME FOR STRONG CONVECTION AND
THUNDERSTORMS.
AS THIS FAIRLY POTENT UPPER LOW TRACKS EWD ACROSS SRN MANITOBA AND
WRN ONTARIO...COLD CANADIAN AIR WILL BE DRAWN SWD INTO THE SYSTEM
AND FILTER INTO SECTIONS OF THE NORTHLAND. AFTER THE FAIRLY MILD
TEMPS WED AND THUR...CONDITIONS WILL BECOME RATHER COOL FRI AND SAT
WITH THIS SYSTEM...WITH HIGHS IN THE 50S AND 60S...AND OVERNIGHT
LOWS IN THE UPPER 30S AND LOWER 40S. WILL LIKELY SEE A FEW CAA
SHOWERS FRI AND SAT DURING THE AFTERNOON...WITH POSSIBLY SOME
CLEARING AND DRYING AT NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 645 AM CDT SUN SEP 15 2013
IFR CIGS AT BRD HIB AND DLH WILL LIFT TO LOW-END MVFR BY 14/15Z.
MOST OF THE MVFR CIGS WILL PERSIST THROUGH THE EARLY AFTERNOON
FROM HIB SOUTHWARD...AND ERODE NORTH TO THE SOUTH FROM 20Z-23Z.
WINDS WILL INCREASE OUT OF THE NE THIS MORNING...WITH GUSTS UP TO
20 KT...BUT DIMINISH IN INTENSITY BY THE MID AFTERNOON. WINDS
BECOME LIGHT TONIGHT AND SKIES REMAIN CLEAR THROUGH THE EVENING.
COULD SEE PATCHY FOG DEVELOP...MAINLY AROUND HIB...BRD AND HYR
AFTER 07/08Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 38 62 42 / 20 0 0 0
INL 59 30 66 39 / 0 0 0 0
BRD 63 36 65 45 / 10 0 0 0
HYR 60 30 64 38 / 20 0 0 0
ASX 57 34 63 39 / 40 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
MNZ010>012-018>021-026-035>038.
WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
WIZ001>004-006>009.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
140>148.
&&
$$
UPDATE...GROCHOCINSKI
SHORT TERM...GRANING
LONG TERM...BJT
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
717 AM CDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 717 AM CDT SUN SEP 15 2013
RAIN...SHOWERS AND ISOLATED THUNDERSTORMS ARE EXITING A BIT SLOWER
THAN FORECAST. A NEW FORECAST IS OUT WHICH DELAYS THE RAIN EXITING
BY 3 HOURS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 15 2013
TODAY AND TONIGHT...THE ONGOING DISTURBANCE AND ASSOCIATED SHOWERS
AND THUNDERSTORMS ACROSS SOUTHWEST AND SOUTH CENTRAL NEBRASKA IS
EXPECTED TO EXIT THE FORECAST AREA BY MID MORNING.
A STRONG CANADIAN COLD FRONT WILL SWEEP THE FORECAST AREA THIS
MORNING. THIS HIGH PRESSURE SYSTEM IS EXPECTED TO TRACK INTO THE
UPPER MIDWEST TONIGHT. THIS WILL PRODUCE UPSLOPE EAST WINDS ACROSS
THE FORECAST AREA WHICH COULD PRODUCE LOW CLOUDINESS TONIGHT. ITS
NOT CLEAR THIS WILL HAPPEN SINCE THE MODEL FORECAST SOUNDINGS SHOW
LOW LEVEL MOISTURE INCREASING BUT THIS DOES NOT ALWAYS PRODUCE LOW
CLOUDINESS.
STRATUS IS EXPECTED ACROSS MUCH OF THE FORECAST AREA THIS MORNING
AND THIS SHOULD KEEP HIGH TEMPERATURES IN THE 60S TO AROUND 70 FOR
HIGHS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
FOR MONDAY...RETURN FLOW SETS UP ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA DURING THE DAY AS SURFACE HIGH PRESSURE BUILDS EAST
ACROSS THE GREAT LAKES. MOISTURE AND LIFT IS SHOWN TO INCREASE
INTO THE AFTERNOON HOURS AS A WEAK WAVE LIFTS ACROSS THE NORTHERN
AND CENTRAL PLAINS. BEST CHANCES OF PRECIPITATION APPEAR TO BE
FOCUSED DURING THE EVENING AND POSSIBLY OVERNIGHT HOURS ACROSS
SOUTHERN AND EASTERN PORTIONS OF THE FORECAST AREA...GENERALLY
TIED TO THE BEST MOISTURE TRANSPORT AND STRENGTHENING LOW LEVEL
JET. HIGHS ON MONDAY WILL ONCE AGAIN BE BELOW AVERAGE...PARTIALLY
DUE TO PERSISTENT OVERCAST CONDITIONS. THE REGION WILL SEE A QUICK
WARM UP FOR TUESDAY AND WEDNESDAY AS A UPPER TROUGH DEEPENS ACROSS
THE PACIFIC NORTHWEST. HIGHS WILL RISE WELL INTO THE 80S FOR MOST
LOCATIONS BOTH DAYS...WITH THE HIGHEST READINGS GENERALLY FOUND
ACROSS THE EASTERN PANHANDLE AND SOUTHWEST NEBRASKA. THERE MAY BE
A FEW STORMS LINGERING ACROSS THE EAST EARLY TUESDAY...AND THEN
POSSIBLY FORMING LATE WEDNESDAY ACROSS THE WEST AS THE UPPER
TROUGH APPROACHES...BUT MOST LOCATIONS SHOULD REMAIN PRECIP FREE
MIDWEEK. A STRONG COLD FRONT ASSOCIATED WITH THE PAC NW TROUGH
WILL CRUISE THROUGH THE FORECAST AREA LATE ON WEDNESDAY...BRINGING
A CHANCE OF STORMS BACK TO THE AREA. PREVIOUS FORECAST INTRODUCED
A SLIGHT CHANCE MENTION FOR MOST PLACES...WILL GENERALLY MAINTAIN
AS THERE REMAINS SOME DISAGREEMENT BETWEEN THE LONGER RANGE
SOLUTIONS....THIS IS DESPITE THE ALL BLEND INDICATING SOME CHANCE
WORDING. THE 00Z GFS IS STRONGER WITH THE TROUGH AND FOCUSES MOST
OF THE QPF ACROSS NORTH CENTRAL NEBRASKA...THE 00Z EURO IS MUCH
MORE PROGRESSIVE WITH THE FROPA AND GENERATES LESS QPF COVERAGE.
OTHERWISE BEHIND POST FRONTAL CONDITIONS SEASONAL TEMPERATURES
WILL BE EXPECTED WITH GENERALLY DRY CONDITIONS FOR THE END OF THE
WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 632 AM CDT SUN SEP 15 2013
IFR/MVFR CIGS AND AREAS OF RAIN/ISOLATED TSTMS WILL IMPROVE TO
MVFR/VFR LATE THIS MORNING AND VFR FOR A FEW HOURS THIS AFTN. HIGH
PRESSURE ACROSS SASKATCHAWAN WILL BUILD INTO THE UPPER MIDWEST
TONIGHT WITH EASTERLY UPSLOPE WINDS DEVELOPING ACROSS WRN/NCNTL
NEB. THE RAP MODEL AND OTHER SUGGEST STATUS WILL REDEVELOP WITH
MVFR CIGS FORMING...PERHAPS IFR ALONG AND/OR WEST OF HIGHWAY 83.
LASTLY...VFR AT KLBF COULD BECOME MVFR AT ANY TIME AS WEAK HIGH
PRESSURE FROM THE HEAVY RAIN ERODES.
&&
.HYDROLOGY...
ISSUED AT 717 AM CDT SUN SEP 15 2013
A COORDINATION CALL WITH THE MB RIVER FORECAST CENTER INDICATES
THE GAGE READINGS AT WELDONA AND BALZAC MAY NOT BE FAULTY. WFO BOU
IS ATTEMPTING TO CONTACT LOCAL OFFICICAL TO GET VISUAL
CONFIRMATION AT THESE LOCATIONS. UNTIL THIS PROCESS IS COMPLETE
THE GAGE READINGS WILL USED AT FACE VALUE AND RECORD FLOODING WILL
BE FORECAST AT BALZAC.
THERE IS NO CHANGE TO THE FORECAST AT ROSCOE PENDING VERIFICATION
OF THE BALZAC AND WELDONA GAGE READINGS.
OTHERWISE...HEAVY RAIN HAS FALLEN OVERNIGHT IN THE SOUTH PLATTE
BASIN BELOW WELDONA WITH LOCAL RAINFALL AMOUNTS OF 2.31 INCHES AT
SIDNEY AND 2.82 INCHES AT NORTH PLATTE. THIS COMPLICATES THE FORECAST
PROCESS OF THE IMPENDING FLOOD WAVE. THE FLOOD WAVE IS APPROACHING
THE BALZAC GAGE BELOW WELDONA THIS MORNING AND THE RIVER SHOULD
CREST THIS MORNING. THE FORECAST FOR RIVER POINTS BELOW
BALZAC...INCLUDING NEBRASKA ARE UNCERTAIN.
THE LATEST FORECAST FOR ROSCOE ISSUED SATURDAY EVENING SHOWS THE
SOUTH PLATTE RISING TUESDAY AND CRESTING AROUND 9 FEET THURSDAY.
FLOOD STAGE IS 9.0 FEET. A FLOOD WATCH IS IN EFFECT FOR THE SOUTH
PLATTE RIVER AT ROSCOE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
HYDROLOGY...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
632 AM CDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN SEP 15 2013
TODAY AND TONIGHT...THE ONGOING DISTURBANCE AND ASSOCIATED SHOWERS
AND THUNDERSTORMS ACROSS SOUTHWEST AND SOUTH CENTRAL NEBRASKA IS
EXPECTED TO EXIT THE FORECAST AREA BY MID MORNING.
A STRONG CANADIAN COLD FRONT WILL SWEEP THE FORECAST AREA THIS
MORNING. THIS HIGH PRESSURE SYSTEM IS EXPECTED TO TRACK INTO THE
UPPER MIDWEST TONIGHT. THIS WILL PRODUCE UPSLOPE EAST WINDS ACROSS
THE FORECAST AREA WHICH COULD PRODUCE LOW CLOUDINESS TONIGHT. ITS
NOT CLEAR THIS WILL HAPPEN SINCE THE MODEL FORECAST SOUNDINGS SHOW
LOW LEVEL MOISTURE INCREASING BUT THIS DOES NOT ALWAYS PRODUCE LOW
CLOUDINESS.
STRATUS IS EXPECTED ACROSS MUCH OF THE FORECAST AREA THIS MORNING
AND THIS SHOULD KEEP HIGH TEMPERATURES IN THE 60S TO AROUND 70 FOR
HIGHS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
FOR MONDAY...RETURN FLOW SETS UP ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA DURING THE DAY AS SURFACE HIGH PRESSURE BUILDS EAST
ACROSS THE GREAT LAKES. MOISTURE AND LIFT IS SHOWN TO INCREASE
INTO THE AFTERNOON HOURS AS A WEAK WAVE LIFTS ACROSS THE NORTHERN
AND CENTRAL PLAINS. BEST CHANCES OF PRECIPITATION APPEAR TO BE
FOCUSED DURING THE EVENING AND POSSIBLY OVERNIGHT HOURS ACROSS
SOUTHERN AND EASTERN PORTIONS OF THE FORECAST AREA...GENERALLY
TIED TO THE BEST MOISTURE TRANSPORT AND STRENGTHENING LOW LEVEL
JET. HIGHS ON MONDAY WILL ONCE AGAIN BE BELOW AVERAGE...PARTIALLY
DUE TO PERSISTENT OVERCAST CONDITIONS. THE REGION WILL SEE A QUICK
WARM UP FOR TUESDAY AND WEDNESDAY AS A UPPER TROUGH DEEPENS ACROSS
THE PACIFIC NORTHWEST. HIGHS WILL RISE WELL INTO THE 80S FOR MOST
LOCATIONS BOTH DAYS...WITH THE HIGHEST READINGS GENERALLY FOUND
ACROSS THE EASTERN PANHANDLE AND SOUTHWEST NEBRASKA. THERE MAY BE
A FEW STORMS LINGERING ACROSS THE EAST EARLY TUESDAY...AND THEN
POSSIBLY FORMING LATE WEDNESDAY ACROSS THE WEST AS THE UPPER
TROUGH APPROACHES...BUT MOST LOCATIONS SHOULD REMAIN PRECIP FREE
MIDWEEK. A STRONG COLD FRONT ASSOCIATED WITH THE PAC NW TROUGH
WILL CRUISE THROUGH THE FORECAST AREA LATE ON WEDNESDAY...BRINGING
A CHANCE OF STORMS BACK TO THE AREA. PREVIOUS FORECAST INTRODUCED
A SLIGHT CHANCE MENTION FOR MOST PLACES...WILL GENERALLY MAINTAIN
AS THERE REMAINS SOME DISAGREEMENT BETWEEN THE LONGER RANGE
SOLUTIONS....THIS IS DESPITE THE ALL BLEND INDICATING SOME CHANCE
WORDING. THE 00Z GFS IS STRONGER WITH THE TROUGH AND FOCUSES MOST
OF THE QPF ACROSS NORTH CENTRAL NEBRASKA...THE 00Z EURO IS MUCH
MORE PROGRESSIVE WITH THE FROPA AND GENERATES LESS QPF COVERAGE.
OTHERWISE BEHIND POST FRONTAL CONDITIONS SEASONAL TEMPERATURES
WILL BE EXPECTED WITH GENERALLY DRY CONDITIONS FOR THE END OF THE
WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 632 AM CDT SUN SEP 15 2013
IFR/MVFR CIGS AND AREAS OF RAIN/ISOLATED TSTMS WILL IMPROVE TO
MVFR/VFR LATE THIS MORNING AND VFR FOR A FEW HOURS THIS AFTN. HIGH
PRESSURE ACROSS SASKATCHAWAN WILL BUILD INTO THE UPPER MIDWEST
TONIGHT WITH EASTERLY UPSLOPE WINDS DEVELOPING ACROSS WRN/NCNTL
NEB. THE RAP MODEL AND OTHER SUGGEST STATUS WILL REDEVELOP WITH
MVFR CIGS FORMING...PERHAPS IFR ALONG AND/OR WEST OF HIGHWAY 83.
LASTLY...VFR AT KLBF COULD BECOME MVFR AT ANY TIME AS WEAK HIGH
PRESSURE FROM THE HEAVY RAIN ERODES.
&&
.HYDROLOGY...
ISSUED AT 632 AM CDT SUN SEP 15 2013
RECORD FLOODING ON THE SOUTH PLATTE RIVER IN GREELEY
COLORADO HAS DISABLED THE DOWNSTREAM RIVER GAGE AT WELDONA AND BALZAC.
MEANWHILE...HEAVY RAIN HAS FALLEN OVERNIGHT IN THE SOUTH PLATTE
BASIN BELOW WELDONA. BOTH OF THESE DEVELOPMENTS COMPLICATES THE
FORECAST PROCESS OF THE IMPENDING FLOOD WAVE. THE FLOOD WAVE IS
APPROACHING THE BALZAC GAGE BELOW WELDONA THIS MORNING AND THE RIVER
SHOULD CREST MONDAY MORNING. AT 530 AM CDT IT APPEARED THE GAGE
WAS FAILING LIKE THE WELDONA GAGE. THE FORECAST FOR RIVER POINTS
BELOW BALZAC...INCLUDING NEBRASKA ARE UNCERTAIN.
THE LATEST FORECAST FOR ROSCOE ISSUED SATURDAY EVENING SHOWS THE
SOUTH PLATTE RISING TUESDAY AND CRESTING AROUND 9 FEET THURSDAY.
FLOOD STAGE IS 9.0 FEET. A FLOOD WATCH IS IN EFFECT FOR THE SOUTH
PLATTE RIVER AT ROSCOE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
HYDROLOGY...CDC
THE AREA FORECAST DISCUSSION FOUND BELOW.
WARMING TEMPERATURES ALOFT AND COOLING LOW LEVELS WILL MOSTLY
SHUTOFF PRECIPITATION CHANCES TONIGHT ALTHOUGH A FEW LINGERING
SHOWERS NOT OUT OF THE QUESTION DUE TO WEAK ELEVATED THETAE
ADVECTION. THERE WILL BE MORE SHOWERS AND THUNDERSTORMS MONDAY AS
A SHORTWAVE TROUGH PUNCHES ACROSS THE AREA. AS THE TROUGH MOVES
EAST WILL START TO SEE CLEAR FROM WEST TO EAST LATE IN THE DAY AND
CONTINUING THROUGH THE EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 323 AM MDT SUN SEP 15 2013
MODELS CONTINUE TO INDICATE A MUCH DRIER AND MORE NORMAL PATTERN
FROM TUESDAY THROUGH THE WEEKEND. PROGRESSIVE TROUGH MOVING INTO
THE PACIFIC NORTHWEST ON TUESDAY WILL CAUSE SOUTHWESTERLY MIDLEVEL
FLOW TO STRENGTHEN ACROSS THE REGION. 700MB TEMPS RISE TO A WARM
13C SO TEMPS WILL BE ABOVE NORMAL BY ABOUT 5-10 DEGREES. SOUTHWEST
WINDS WILL BE BREEZY ALONG AND WEST OF THE LARAMIE RANGE IN THE
AFTN. TROUGH MOVES ACROSS MONTANA ON WEDNESDAY AND THEN INTO THE
DAKOTAS BY THURSDAY. WEDNESDAY WILL BE ANOTHER WARM DAY WITH
GOOD DOWNSLOPING. LOW AND MIDLEVEL MOISTURE IS PRETTY MEAGER WITH
THIS SYSTEM...BUT DO HAVE SLIGHT CHANCE POPS OVER THE PLAINS ON
WEDNESDAY NIGHT IN THE CONVERGENCE ALONG THE COLD FRONT. SFC HIGH
MOVES OVERHEAD ON THURSDAY AND FRIDAY AND WITH COOLER TEMPS...IT
WILL BE VERY NICE SEPTEMBER DAYS. EXPECT WARMER TEMPS DURING THE
WEEKEND AS SOUTHWESTERLY FLOW ALOFT BECOMES ESTABLISHED ONCE AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1050 PM MDT SAT SEP 14 2013
LATEST HRRR GUIDANCE SHOWING A WIDESPREAD IFR/LIFR EVENT TAKING
SHAPE AS A COLD FRONT PUSHES SOUTH INTO NORTHERN COLORADO.
NORTHEAST UPSLOPING WINDS WILL PERSIST MOST OF THE NEXT 24-36
HOURS AND BRING DOWN CEILINGS AT AIRPORTS EAST OF THE LARAMIE
RANGE SHORTLY AFTER 08Z AT CHADRON...THEN SPREADING QUICKLY SOUTH
AND SOUTHWEST. WE COULD STAY DOWN ALL DAY SUNDAY AND MAYBE GO TO
MVFR DURING THE AFTERNOON. WITH UPSLOPING WINDS AND COOL
TEMPERATURES...DO EXPECT IFR/LIFR TO RETURN SUNDAY NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 323 AM MDT SUN SEP 15 2013
SHOWERS AND THUNDERSTORMS WILL AGAIN OCCUR OVER SOUTHEAST WYOMING
TODAY WHILE SHOWERS SHOULD END THIS MORNING OVER THE NEBRASKA
PANHANDLE. MOST SHOWER ACTIVITY WILL BE FOUND ALONG AND WEST OF THE
LARAMIE RANGE. A FLASH FLOOD WATCH IS IN EFFECT FOR THE SOUTHERN
LARAMIE RANGE AND FOOTHILLS WHERE THE SOIL IS SATURATED AND PRONE
TO RAPID RUNOFF SHOULD THUNDERSTORMS DEVELOP OVER THE AREA. SHOWERS
AND THUNDERSTORMS WILL MOSTLY DISSIPATE THIS EVENING BUT ONE MORE
ROUND OF SHOWERS AND THUNDERSTORMS IS POSSIBLE MONDAY AFTERNOON...
THEN DRIER WEATHER FOR THE REST OF THE WEEK.
&&
.HYDROLOGY...
ISSUED AT 227 PM MDT SAT SEP 14 2013
FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS AFTERNOON FOR
THE SOUTHERN LARAMIE RANGE AND FOOTHILLS. POTENTIAL FOR FLOODING
STILL EXISTS ALTHOUGH THAT IS PREDICATED ON ELEVATED THUNDERSTORMS
DEVELOPING THIS AFTERNOON WHICH IS NOT A CERTAINTY OVER THE
LARAMIE RANGE. LOW LEVEL INVERSION WILL SET UP WITH THE PASSAGE
OF A COLD FRONT WHICH MEANS SURFACE BASED THUNDERSTORMS NOT LIKELY
OVER THE LARAMIE RANGE OR POINTS EAST. THE MODLES DO POINT AS 20
TO 30 KT SOUTHEAST WIND DEVELOPING NEAR THE TOP OF THE INVERSION
NEAR THE SOUTHERN LARAMIE RANGE WITH STEEP ELEVATED LAPSE RATES IN
PLACE. THIS MAY BE ENOUGH TO POP A FEW ELEVATED THUNDERSTORMS
WHICH THEN WOULD HAVE TO POTENTIAL TO PRODUCE FLASH FLOODING.
ALSO...FLASH FLOOD GUIDANCE VALUES ARE VERY LOW SO IT WILL NOT TAKE
MUCH HEAVY RAIN TO CAUSE FLASH FLOODING. WILL ALSO SEE A PERIOD OF
MODERATE STRATAFORM RAINFALL THIS MORNING OVER THE AREA WHICH WILL
KEEP THE SOIL VERY SATURATED.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR WYZ116-117.
NE...NONE.
&&
$$
SHORT TERM...LIEBL
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...LIEBL
HYDROLOGY...LIEBL
AREA FORECAST DISCUSSION
NWS TUCSON AZ
200 PM MST SUN SEP 15 2013
.SYNOPSIS...THERE WILL BE ENOUGH MOISTURE FOR ISOLATED TO SCATTERED
THUNDERSTORMS MAINLY EAST OF TUCSON TO START THE WEEK. THE DRIER
WESTERLY FLOW WILL CONTINUE TO DIMINISH MOISTURE THROUGH THE
WEEK...BUT WE MAY HOLD ON TO ENOUGH TO KEEP A FEW MOUNTAIN
THUNDERSTORMS AROUND IN THE AFTERNOONS.
&&
.DISCUSSION...ISOLATED CONVECTION STARTING THIS AFTERNOON BUT
MOISTURE IS GETTING MORE AND MORE MARGINAL. GOES SOUNDER ESTIMATED
PRECIPITABLE WATER DOWN TO AROUND .95 TO 1 INCH IN A MODEST BUT
DRIER WESTERLY FLOW AT MOST LEVELS. EXCEPTION IS LOWER LEVELS WITH
CONTINUED EASTERLY AND SOUTHEASTERLY COMPONENTS. SURFACE DEWPTS DOWN
ABOUT 2 TO 4 DEGREES OVERALL THE PAST 24 HOURS FROM TUCSON
WESTWARD...BUT LATEST HRRR CONTINUES NEAR SURFACE STREAMLINES FROM
NEW MEXICO INTO EASTERN ZONES INTO EARLY MONDAY. THIS WILL PROBABLY
HELP KEEP ISOLATED TO LOW END SCATTERED CONVECTION GOING MAINLY EAST
OF TUCSON WITH AN EMPHASIS ON THE MOUNTAINS.
LATEST NAMDNG5 CONTINUES EASTERLY SURFACE WINDS INTO TUESDAY AS FAR
WEST AS TUCSON...UP TO BREEZY LEVELS AT TIMES. THIS COULD CAUSE
PROBLEMS WITH OVERNIGHT LOWS IN A COUPLE OF LOCATIONS WITH THE
POTENTIAL FOR THE BOUNDARY LAYER TO REMAIN MIXED AND KEEP
TEMPERATURES UP A BIT. AT THAT POINT THE LOWER LEVEL FLOW STARTS TO
STACK MORE NEATLY AND ADDITIONAL DRYING WILL PROBABLY SEE EVEN
EASTERN MOUNTAINS LOSING THUNDERSTORMS WITH A BELOW 10 PERCENT
FORECAST AREA WIDE BY WEDNESDAY.
SOME MOISTURE PUSH FROM THE TROPICS INTO SONORA AND CHIHUAHUA IS
EXPECTED LATER IN THE WEEK...BUT IS STILL EXPECTED TO HAVE
DIFFICULTY MAKING MUCH PROGRESS FURTHER NORTH WITH THE UNFAVORABLE
WESTERLY FLOW. A WEAK SHORTWAVE RIDGE COULD ALLOW ENOUGH OF A BREAK
IN THE FLOW FOR AREAS MAINLY NEAR THE INTERNATIONAL BORDER TO SEE
ISOLATED CONVECTION AGAIN LATER IN THE WEEK.
&&
.AVIATION...VALID THRU 16/21Z.
WEST OF KTUS MOSTLY CLEAR. KTUS EWD/SWD ISOLD-SCT -TSRA/-SHRA THIS
AFTERNOON AND THIS EVENING...AND A FEW -TSRA/-SHRA MAINLY NEAR THE
NEW MEXICO BORDER LATE TONIGHT. OTHERWISE...FEW-BKN CLOUDS
MAINLY AT 6-10K FT AGL THIS AFTERNOON AND THIS EVENING...AND FEW-SCT
CLOUDS MOSTLY ABOVE 10K FT AGL LATE TONIGHT. SURFACE WIND GENERALLY
OUT OF THE EAST AT 5-15KTS AND GUSTY AT TIMES INTO MONDAY. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY
EAST OF TUCSON THROUGH TUESDAY. SOME DRYING THROUGH THE WEEK BUT WE
MAY HOLD ON TO ENOUGH MOISTURE FOR ISOLATED MOUNTAIN
THUNDERSTORMS...ESPECIALLY NEAR THE INTERNATIONAL BORDER. GUSTY EAST
WINDS AT TIMES THROUGH TUESDAY. OTHERWISE...DAYTIME TEMPERATURES
WILL BE A FEW DEGREES ABOVE NORMAL THIS WEEK.
&&
.HYDROLOGY...THE SAN FRANCISCO RIVER AT CLIFTON CRESTED AT 24.1 FEET
AT 1045 AM MST...BUT HAS FALLEN TO 20 FEET AS OF 130 PM MST. THE
RIVER IS EXPECTED TO CONTINUE TO GRADUALLY FALL THIS AFTERNOON.
THE FLOWS FROM THE SAN FRANCISCO WILL MOVE INTO THE GILA RIVER LATER
TODAY WHICH IS EXPECTED TO REMAIN ABOVE BANKFULL AT SOLOMON BUT
BELOW MINOR FLOOD STAGE. THIS WOULD STILL HAVE THE POTENTIAL TO
FLOOD LOW LYING AGRICULTURAL AREAS NEAR THE RIVER.
RISES ON THE GILA RIVER IN NEW MEXICO WILL CONTINUE TO MAKE THEIR
WAY DOWNSTREAM INTO ARIZONA TODAY. THE GILA RIVER AT RED ROCK NEW
MEXICO CRESTED JUST BEFORE 10 AM MST THIS MORNING. WHILE RISES WILL
OCCUR DURING THE EVENING HOURS ON THE GILA RIVER AT DUNCAN AND SOUTH
OF CLIFTON...THE RIVER SHOULD REMAIN BELOW BANKFULL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
FLOOD WARNING IN EFFECT TODAY FOR THE SAN FRANCISCO
RIVER AT CLIFTON.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/DROZD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1206 PM MDT SUN SEP 15 2013
.UPDATE...
&&
.SHORT TERM...VERY HEAVY RAIN HAS DEVELOPED OVER THE FOOTHILLS AND
ADJACENT PLAINS OVER THE PAST SEVERAL HOURS. RAINFALL RATES ARE
EVEN HIGHER THAN EXPECTED WITH RATES NOW EXCEEDING ONE INCH IN
LESS THAN AN HOUR OVER NORTHERN PORTIONS OF THE DENVER
AREA...INCLUDING BROOMFIELD...ADAMS...AND JEFFERSON COUNTIES.
EXPECT THESE CONDITIONS TO CONTINUE FOR THE REST OF THE AFTERNOON.
AGAIN ANOTHER VERY DANGEROUS SITUATION WITH MULTIPLE FLASH FLOOD
AND FLOOD WARNINGS ONGOING FOR THE AREA. RAIN IS MORE SCATTERED IN
COVERAGE FURTHER EAST ON THE PLAINS SO EXPECTING A LOWER IMPACT OF
THE CURRENT RAINFALL SITUATION.
.HYDROLOGY...CURRENT FLASH FLOOD WARNINGS OUT FOR FIRE BURN AREAS
AND OTHER LOCATIONS RECEIVING VERY HEAVY RAIN. HIGHER RAINFALL
RATES HAVE AGAIN DEVELOPED WITH RATES OF ONE INCH IN 30 MINUTES OR
LESS IN THE HEAVIEST RAIN. DANGEROUS SITUATION DEVELOPING WITH
POTENTIAL FOR ENHANCED FLOODING AND CONTINUES RIVER AND STREAM
RISES EXPECTED. ONGOING AREAL FLOOD WARNINGS AND RIVER FLOOD
WARNINGS FOR MUCH OF THE AREA NORTH AND NORTHEAST OF DENVER.
&&
.PREV DISCUSSION... /ISSUED 925 AM MDT SUN SEP 15 2013/
UPDATE...
SHORT TERM...RAIN SHOWERS HAVE BEEN RAPIDLY DEVELOPING OVER THE
FOOTHILLS AND PLAINS DURING THE PAST SEVERAL HOURS. PLATTEVILLE
PROFILER SHOWING WEAK UPSLOPE FLOW FROM THE NORTHEAST HAS BEEN
DEEPENING OVER THE PAST SEVERAL HOURS TO MOUNTAIN TOP LEVEL. THE
WEAK FRONTAL BOUNDARY IS FINALLY BEGINNING TO PUSH SOUTH AND
SOUTHWEST AND JUST MOVING INTO THE FRONT RANGE AREA. FORECASTS
LOOK IN GOOD SHAPE FOR NOW.
&&
.AVIATION...CEILINGS LOWERING AND WILL CONTINUE TO LOWER FROM THE
NORTH TO IFR CONDITIONS IN THE NEXT FEW HOURS AS RAIN BEGINS TO
SPREAD ACROSS THE AREA FROM THE NORTH AND NORTHEAST. RAINFALL
SHOULD BE DIMINISHING THIS EVENING WITH IMPROVING CONDITIONS.
POSSIBLE FOG LATER TONIGHT.
.HYDROLOGY...RAIN DEVELOPING AND WILL BECOME MORE WIDESPREAD BY
LATER THIS MORNING OVER THE ENTIRE AREA...WITH HIGHER COVERAGE
OVER THE FOOTHILLS AND ADJACENT PLAINS. CURRENT RAINFALL OVER
LARIMER COUNTY GAUGES SHOWING RAINFALL RATES GENERALLY FROM .20 TO
.50 OF AN INCH PER HOUR WITH THE HEAVIER SHOWERS. JUST ISSUED AN
AREAL FLOOD WARNING FOR MUCH OF THE FRONT RANGE FOOTHILLS...AND
ADJACENT PLAINS AND STRETCHING NORTHEAST TO COVER AREAS ALONG THE
SOUTH PLATTE UP THROUGH JULESBURG AND AREAS ALONG THE CACHE LA
POUDRE. STILL COULD SEE 1 TO 2 INCHES OF ADDITIONAL RAINFALL
THROUGH THIS EVENING ESPECIALLY IN THE FOOTHILLS.
.PREV DISCUSSION... /ISSUED 338 AM MDT SUN SEP 15 2013/
SHORT TERM...REMNANTS OF WK UPPER LEVEL TROUGH WILL SHEAR ACROSS THE
AREA THRU TONIGHT WITH SOME MINOR MID LVL ASCENT. MEANWHILE LOW
LVL WINDS ARE CURRENTLY NLY ALONG THE FNT RANGE BUT ARE FCST TO
BECOME MORE NELY LATER THIS MORNING INTO THE AFTN HOURS BEHIND A
COOL FNT. THIS SHOULD ALLOW FOR INCREASING PCPN IN THE NRN
FOOTHILLS AND MTNS EAST OF THE DIVIDE THIS MORNING WHICH WILL
SPREAD SOUTHWARD THRU THE DAY. AT THIS TIME HIGHEST PCPN AMOUNTS
SHOULD FOCUS IN AND NR THE FOOTHILLS AND IN THE MTNS EAST OF THE
DIVIDE. THE GFS AND HRRR SHOW POTENTIAL RAINFALL AMOUNTS RANGING
FROM 1 TO 2 INCHES OVER THE HIGHER TERRAIN WHILE THE ECMWF KEEPS
THE HEAVIER AMOUNTS FOCUSED EAST OF THE HIGHER TERRAIN OVER THE
FRONT RANGE URBAN CORRIDOR THRU THIS AFTN. AT THIS POINT WILL KEEP
THE HEAVIER AMOUNTS OVER THE HIGHER TERRAIN.
MEANWHILE WITH CONSIDERABLE CLOUD COVER THERE WILL BE LIMITED
INSTABILITY SO THE PCPN WILL BE MORE OF A STRATIFORM EVENT WITH
RAINFALL RATES MAINLY AROUND ONE QUARTER INCH PER HOUR. WILL KEEP
FFA IN PLACE HOWEVER BIGGWST CONCERNS WOULD BE CONSIDERABLE AMOUNT
OF ROCK AND MUD SLIDE ACTIVITY DUE TO EXTREMELY SATURATED GROUND.
HIGH THIS AFTERNOON OVER NERN CO MAY NOT GET MUCH ABV 60 EXCEPT OVER
THE FAR NERN CORNER WHERE HIGHS MAY GET CLOSE TO 70.
FOR TONIGHT THERE WILL BE SOME LINGERING RAIN THEU EVENING WHICH
WILL GRADUALLY END FM NORTH TO SOUTH OVERNIGHT. TEMPS MAY BE COLD
ENOUGH FOR SOME SNOW OVER THE HIGHER MTNS ABV 11000 FT BEFORE PCPN
ENDS.
LONG TERM...MODELS SHOW THE WEAK UPPER TROUGH TO MOVE ACROSS THE
FORECAST AREA ON MONDAY...THEN UPPER RIDGING IS PROGGED INTO
TUESDAY AFTERNOON. SOUTHWESTERLY FLOW ALOFT MOVES IN TUESDAY
NIGHT...WITH AN UPPER TROUGH GETTING INTO THE NORTHERN GREAT BASIN
BY 12Z WEDNESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA MONDAY THROUGH TUESDAY NIGHT.
THE BOUNDARY LAYER PRESSURE AND WIND FIELDS SHOW SOUTHEASTERLIES
OVER THE PLAINS ON MONDAY...THEN NORMAL DIURNAL PATTERNS KICK IN
MONDAY NIGHT INTO TUESDAY. LOW LEVEL TROUGHING AND DOWNSLOPING ARE
BOTH PROGGED LATER TUESDAY INTO TUESDAY NIGHT. CONCERNING MOISTURE
..MONDAY DRIES OUT SOMEWHAT...WITH FURTHER DRYING ON TUESDAY.
PRECIPITABLE WATER VALUES ARE IN THE 0.75-0.85 INCH RANGE OVER THE
WESTERN PLAINS MONDAY...DRYING INTO THE 0.50 TO 0.75 INCH RANGE
BY LATER TUESDAY. VALUES ARE HIGHER OVER THE EASTERN PLAINS ON
MONDAY...BUT DRY TO SIMILAR VALUES BY LATER TUESDAY. THE BOUNDARY
LAYER DEW POINTS ARE PROGGED IN THE LOWER TO MID 50S F OVER THE
PLAINS MONDAY INTO TUESDAY MONRING...THEN THEY DECREASE INTO THE
40S TO LOWER 50S F LATER TUESDAY AND TUESDAY NIGHT. VALUES ARE IN
THE MID 30S TO MID 40S OVER THE MOUNTAINS ALL FOUR PERIODS. THERE
IS SOME CAPE AROUND BOTH LATE DAY MONDAY AND LATE DAY TUESDAY...
BUT NOTHING SIGNIFICANT. THE QPF FIELDS HAVE LIMITED MEASURABLE
RAINFALL AMOUNTS MONDAY...NOTHING MONDAY NIGHT OR TUESDAY MONRING
..THEN A TAD LATE DAY TUESDAY IN THE MOUNTAINS. SO FOR POPS...
20-40%S IN THE MOUNTAINS LATE DAY MONDAY AND LATE DAY TUESDAY. FOR
THE PLAINS...10-20%S LATE DAY MONDAY...NONE TUESDAY. FOR
TEMPERATURES...MONDAY`S HIGHS ARE 3-7 C WARMER THAN TODAY`S.
TUESDAY`S HIGHS ARE 1-4 C WARMER THAN MONDAY`S. FOR THE LATER DAYS
..WEDNESDAY THROUGH SATURDAY...MODELS BRING AN UPPER TROUGH ACROSS
THE CWA WEDNESDAY AFTERNOON INTO EARLY THURSDAY...ALONG WITH AN
ACCOMPANYING COLD FRONT. AFTER THAT...UPPER RIDGING MOVES IN
THROUGH SATURDAY. MOISTURE IS LIMITED AND TEMPERATURES ARE ABOVE
SEASONAL NORMALS.
AVIATION...CEILINGS SHOULD GRADUALLY DROP INTO THE IFR CATEGORY LATER
THIS MORNING WITH AREAS OF RAIN DEVELOPING. THIS ACTIVITY WILL
CONTINUE THRU THE AFTN BEFORE ENDING DURING THE EVENING HOURS.
OVERNIGHT LOW CEILINGS AND SOME FOG WILL BE POSSIBLE THRU MON
MORNING.
HYDROLOGY...WILL CONTINUE WITH THE FLASH FLOOD WATCH THROUGH 6 PM
THIS EVENING. AREAS OF RAIN WILL INCREASE THROUGH THE MORNING
HOURS AND CONTINUE THROUGH THE AFTERNOON IN THE MOUNTAINS AND
FOOTHILLS AND ALONG THE FRONT RANGE URBAN CORRIDER. RAINFALL
AMOUNTS OVER THE HIGHER TERRAIN THROUGH 6 PM MAY RANGE FROM 1 TO 2
INCHES WITH ONE HALF INCH TO ONE INCH AT LOWER ELEVATIONS. COULD
SEE A FEW LOCALIZED AREAS OF FLASH FLOODING HOWEVER BIGGEST
CONCERN WILL BE AN INCREASE IN ROCK AND MUD SLIDES IN THE
FOOTHILLS AND MOUNTAINS DUE TO EXTREMELY SATURATED GROUND.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
.RIVER FLOOD WARNINGS CONTINUE ALONG THE CACHE LA POUDRE...BIG
THOMPSON...AND SOUTH PLATTE RIVER OUT THROUGH JULESBURG.
.AREAL FLOOD WARNINGS UNTIL 9 PM THIS EVENING FOR COZ035..036..
038>041..043>045..048>50.
.FLASH FLOOD WATCH UNTIL 6 PM MDT THIS EVENING FOR COZ033>036-
038>041-043.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RJK
AREA FORECAST DISCUSSION
NWS WICHITA KS
301 PM CDT SUN SEP 15 2013
.SYNOPSIS...
ISSUED AT 250 PM CDT SUN SEP 15 2013
A COLD FRONT STRETCHING FROM NORTHEAST TO CENTRAL AND
SOUTHWEST KANSAS IS KEEPING ON ITS SOUTHEAST TRACK. THIS FRONT WILL
PUSH THROUGH THIS EVENING...AND A RIDGE WILL BE ON ITS TAILS FOR
MONDAY. A FAIRLY ACTIVE PATTERN IS IN PLACE TO KEEP SYSTEMS MOVING
ACROSS THE CONUS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 250 PM CDT SUN SEP 15 2013
AS MENTIONED IN THE SYNOPSIS...THE COLD FRONT SHOULD CONTINUE TO
SLIDE THROUGH THE REST OF KANSAS AND INTO OKLAHOMA THIS EVENING
AND TONIGHT. SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO
BUBBLE UP ALONG AND BEHIND THIS FRONTAL FEATURE THIS AFTERNOON
GIVEN DAYTIME HEATING AND . SOME OF THE STORMS COULD BE STRONG
WITH ABOVE 1K J/KG CAPE VALUES MAINLY IN SOUTH CENTRAL
KANSAS...HOWEVER 0-6KM BULK SHEAR VALUES ARE LESS THAN 30KTS
ACCORDING TO THE MODELS DURING THIS RESPECTIVE TIME FRAME FOR ALL
BUT THE RUC WHICH HAS VALUES JUST AT 40KTS. PRECIPITATION ACTIVITY
IS STILL ANTICIPATED TO LINGER INTO MUCH OF MONDAY AND TUESDAY
WHEN ANOTHER SHORTWAVE IN THE MID LEVELS MOVES THROUGH THE AREA.
ANOTHER TROUGH AT 500MB AND 700MB IS GOING TO MOVE ONSHORE ON
TUESDAY...WHILE THE 850MB TROUGH HALTS AND STARTS TO DEVELOP ALONG
THE FRONT RANGE. EVENING POPS ON TUESDAY WERE SLIGHTLY DROPPED
FROM THE PREVIOUS FORECAST...BUT THE MAIN TRENDS FOR ALL OTHER
PARAMETERS WERE MAINTAINED. COOLER AIR ON MONDAY AND CLOUD COVER
WILL KEEP HIGHS BELOW SEASONAL NORMAL BY 5 DEGREES IN SOUTH
CENTRAL KANSAS AND AS MUCH AS 10 DEGREES IN CENTRAL KANSAS.
TUESDAY SHOULD REBOUND BACK TO ABOVE NORMAL IN THE MID TO UPPER
80S.
JUANITA
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 250 PM CDT SUN SEP 15 2013
WEDNESDAY THRU THURSDAY: IN THIS TIME FRAME...THE NEXT SYSTEM IS
EXPECTED TO MOVE THROUGH THE PLAINS. WHILE THE CENTER OF THE LOW
STAYS ACROSS THE CANADIAN AND U.S. BORDER AND MOVES THE FRONT ON
WEDNESDAY INTO THURSDAY...THERE ARE MODEL DIFFERENCES IN ITS TIMING.
ECMWF IS MORE PROGRESSIVE WITH PUSHING THE FRONT THROUGH THE AREA.
THERE COULD BE A CHANGE IN PRECIP ACTIVITY WITH THIS DIFFERENCE.
POPS WERE SLIGHTLY INCREASED FOR THURSDAY AND THURSDAY EVENING WITH
A SMIDGEN OF BETTER CONSISTENCY.
FRIDAY THRU SUNDAY: CURRENT MODEL PREDICTIONS OF THIS TIME FRAME MAKE IT
APPEAR THAT A RIDGE WILL BE IN PLACE. MODEL DISCREPANCIES BEGIN AT
THE START OF NEXT WEEK WHICH MAY MAKE AN IMPACT TO THE FORECAST
FOR SUNDAY DEPENDING ON THE POTENTIAL PROGRESSIVE NATURE OF THE
SYSTEM. THIS IS TOO FAR OUT FOR ANY CERTAINTY IN EITHER PREDICTION
OF THE NEXT SYSTEM TO MOVE THROUGH THE CENTRAL UNITED STATES.
SLIGHT CHANCES WERE PUT IN FOR SUNDAY...BUT AGAIN CONFIDENCE IS
LOW AT THIS TIME.
JUANITA
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1245 PM CDT SUN SEP 15 2013
SCATTERED THUNDERSTORMS EXPECTED TO ERUPT BY 21-22Z NEAR HUT-
ICT...ALONG A COLD FRONT SURGING SOUTH...WITH THIS ACTIVITY
GETTING INTO KCNU 00-01Z. STRONGEST ACTIVITY WILL BE CAPABLE OF
STRONG/GUSTY ERRATIC WINDS...DIME-QUARTER SIZE HAIL AND LOCALLY
HEAVY RAIN. BEHIND INITIAL CONVECTION...OTHER AREAS OF
SHOWERS/THUNDERSTORMS MAY REDEVELOP NORTH OF THE FRONT LATER THIS
EVENING AS LOW-LEVEL JET STRENGTHENS...POSSIBLY AFFECTING THE
ENTIRE AREA. FURTHERMORE...LOW MVFR TO POTENTIALLY IFR CIGS
EXPECTED TO SPREAD SOUTH IN WAKE OF THE FRONT THIS AFTERNOON AND
TONIGHT...ALONG WITH MODEST NORTH/NORTHEAST WINDS.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 65 78 65 86 / 60 50 30 30
HUTCHINSON 62 75 63 85 / 60 50 30 30
NEWTON 61 74 62 83 / 60 50 30 30
ELDORADO 63 78 63 84 / 60 50 30 30
WINFIELD-KWLD 67 81 65 86 / 50 60 30 30
RUSSELL 58 72 61 86 / 40 40 40 30
GREAT BEND 59 73 62 85 / 40 40 40 30
SALINA 60 73 62 84 / 40 40 40 40
MCPHERSON 61 74 63 84 / 50 40 30 40
COFFEYVILLE 66 83 65 86 / 60 60 40 40
CHANUTE 64 78 63 85 / 60 60 40 40
IOLA 63 76 62 84 / 60 50 40 40
PARSONS-KPPF 65 81 64 85 / 60 60 40 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 PM CDT Sun Sep 15 2013
...Update to aviation for 18 Zulu time TAFs...
.SYNOPSIS...
ISSUED AT 1010 AM CDT SUN SEP 15 2013
The 15.12Z raob map showed southwesterly wind vectors with magnitudes
in the 35-40 kt over Kansas. @ 500 hPa, an elongated trof was located
across the northeast Pacific. Shortwave ridging was noted across the
northern Rockies. Another broad ridge stretched across the Deep South.
@ 700 hPa and 850 hPa, some drying was noted at KDDC. The pwat was down
to 1.30", which, statistically speaking, is still fairly high for this
time of year. 850 hPa also showed more warming with observed at 21C.
At the sfc, a frontal boundary was analyzed across western Kansas. In
the tropics, Hurricane Ingrid was located at 22.5N 95.8W @ 15.15Z. Invest
94L 950 miles southwest of the Azores. Tropical Storm Manuel was
at 18.5N 103.9W @ 15.15Z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 403 AM CDT SUN SEP 15 2013
An upper level trough over the Rockies will continue to eject
minor waves into the plains today and tonight. Meanwhile, a
shortwave trough progressing southeastward across the upper Midwest
will help push a fairly strong cold front into southwest Kansas
this afternoon. Thunderstorm chances are fairly good along
and ahead of the front; but these are not expected to be
severe given the lack of shear and marginal surface based CAPE.
The best chance of storms is along and southeast of a line from
Dodge City to Larned after 4 pm. Opted to go with a non-diurnal
temperature trend for today by using the 06Z RUC as a 1st guess,
then modifying the hourly temperatures that seemed too hot ahead
of the front. Temperatures should be falling in the afternoon from
Dodge City northward to interstate 70 as low level stratus invades
from the northern plains. Late afternoon temperatures may be in the
upper 60s around Wakeeney and in the lower 90s for areas southeast
of Dodge City around Medicine Lodge. For tonight, some elevated
showers and thunderstorm may persist through the nigh as upper
level troughing hangs back to the west over Colorado. However,
if the lower levels are stabilized too much by the deep cold
advection, then this activity may not pan out at all. Temperatures
should fall into the 50s to lower 60s by advection alone by
Tuesday morning with low stratus hanging tough.
.LONG TERM...(Monday through Saturday)
ISSUED AT 357 AM CDT SUN SEP 15 2013
There is considerable uncertainty in synoptic scale details in the
extended period with a blocky flow regime likely to persist in the
United States through the last week of September. Global scale
forcing is weak, and the numerical models exhibit considerable
spread, especially in the week two period. The Madden Julian
Oscillation is weak, but most of the global scale models do suggest
a low amplitude coherent signal in Phase 5 of the Wheeler-Hendon
Phase Space Diagram this week. However, the low amplitude of the
signal and the generally weak correlation with mid latitude weather
this time of the year provide little to increase confidence in the
extended forecast. Global relative angular momentum continues below
climatological values, and the recent spike in mountain torque has
ended. The net result is that there is little signal in the Global
Wind Oscillation to provide much guidance, either.
The upper level high over southeastern Alberta will break down and
progress east today and Monday as the upper low near 130W progresses
into the Pacific Northwest. The upper level trough in the northern
stream from near Lake Superior to South Dakota will continue to dig
into the long wave trough in the upper Midwest, and a cold front
will move across most of Kansas before becoming stationary tonight
near the Kansas/Oklahoma border this evening. Most of Kansas will be
under moist east flow Monday with considerable cloud cover, although
the cloudiness may break in the southwest corner of the state during
the afternoon. The cold trough over the Rockies will progress into
Kansas Monday as the block breaks down. Weak upward vertical motion
in a moist atmosphere will favor continued chances for showers and a
few thunderstorms Monday. Instability should be better in far
southwest Kansas near the old frontal zone, especially if breaks in
the cloudiness develop during the afternoon. A modest low level jet
with H8 winds around 30kts will develop Monday night as pressures
fall in the Northern Plains, and low level isentropic lifting will
favor shower and thunderstorm development during the nighttime
hours. The best isentropic lift will propagate into northern Kansas
after 06Z, and thunderstorm chances will decrease in southwest
Kansas.
The surface warm front will mix northward quickly after sunrise
Tuesday, and an elevated mixed layer will spread across western
Kansas during the day. Tuesday and Wednesday should be breezy and
warm with highs in the upper 80s and lower 90s in most areas. By
Wednesday, the jet streak near 170W will dig into the northern
Rockies and will progress slowly eastward Thursday and Friday. The
ECMWF and GEM are more progressive with the trough than the GFS and
develop a deeper closed cyclone than the GFS by 00Z Friday. Most of
the GEM ensemble members also are more progressive than the
deterministic GFS, as are many of the GFS ensemble members. The
preponderance of evidence supports a solution more similar to the
ECMWF later this week. A cold front will move into northwest Kansas
Wednesday evening and should progress across all of western Kansas
by late Thursday morning. Warm temperatures aloft and timing of the
frontal passage during the nighttime and early morning hours are not
favorable for much thunderstorm development along the boundary. Some
post-frontal development is possible Thursday as mid level
temperatures cool and western Kansas comes under the entrance region
of a jet streak.
Upper level ridging will build over Kansas Friday, and the next
upper level trough will dig into the northern Rockies Saturday. The
ECMWF closes off another cyclone over eastern Montana Sunday and
wallows a closed low into the central plains by Tuesday, while the
GFS and most if its ensemble members maintain a more open wave much
farther north than the ECMWF. Confidence is low with evolution of
the upper level trough. The ECMWF may be trending in the right
direction given the blocky flow in North America, but a few more
runs are needed before accepting the ECMWF solution.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1200 PM CDT SUN SEP 15 2013
Messy TAF with deteriorating flight conditions through PD. Stratus is
wrapping around behind a cold front. This front is bisecting the region
and should traverse across the terminals in the next 6 hours. MVFR to
IFR cigs expected in the wake of the front as post frontal lifting occurs.
Thunderstorms should remain southeast of the terminals (although KDDC
will be close). Post frontal showers late tonight possible as well.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 58 73 63 / 30 40 40 30
GCK 81 57 72 61 / 20 30 40 30
EHA 84 57 78 62 / 30 30 40 40
LBL 86 58 77 62 / 30 30 40 40
HYS 77 57 71 62 / 20 30 30 40
P28 91 62 79 66 / 40 60 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Finch
LONG TERM...Ruthi
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
132 PM EDT SUN SEP 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 515 AM EDT SUN SEP 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OVER THE NRN ROCKIES
AND A TROUGH OVER HUDSON BAY RESULTING IN CYCLONIC WNW FLOW THROUGH
THE NRN GREAT LAKES. A SHORTWAVE TROUGH OVER MN AND AREA OF UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 250-300 MB JET OVER NRN
ONTARIO SUPPORTED A LARGE AREA OF RAIN FROM SE MN THROUGH UPPER MI
AND WI. THE STRONGEST 700-500 MB QVECTOR CONV AND HEAVIER PCPN
REMAINED TO THE SOUTH OVER WI. HOWEVER...300K-305K ISENTROPIC LIFT
EXTENDING INTO UPPER MI AHEAD OF THE SFC TROUGH FROM NW IA INTO NW
WI HAS HELPED BRING LIGHT RAIN THROUGH THE CWA. WINDS HAD VEERED
SHARPLY TO THE NE AND INCREASED TO 15 TO 25 KNOTS OVER NRN LAKE
SUPERIOR BEHIND A COLD FRONT SAGGING INTO UPPER MI.
TODAY...RADAR/SATELLITE TRENDS AND MODELS SUGGEST THAT THE SHORTWAVE AND
AREA OF WIDESPREAD RAIN WILL CONTINUE TO MOVE OFF TO THE SOUTHEAST
AND END BY AFTERNOON. HOWEVER...THE CYCLONIC NNE FLOW AND 850 MB
TEMPS FALLING INTO THE 2C TO 4C RANGE BEFORE THE DEEPER MOISTURE
DEPARTS WILL SUPPORT SOME LAKE ENHANCED RAIN/DRIZZLE INTO N CNTRL
UPPER MI ESPECIALLY OVER THE HIGHER TERRAIN WHERE LOW LEVEL UPSLOPE
FLOW IS STRONGEST. ONCE THE DEEP MOISTURE QUICKLY MOVES OUT AROUND
18Z...THE REMAINING PCPN SHOULD END ALONG WITH DIMINISHING CLOUD
COVER.
TONIGHT...HIGH PRESSURE OVER NRN MANITOBA WHERE SOME TEMPS HAVE
FALLEN INTO THE MID AND UPPER 20S...WILL BUILD INTO UPPER MI
BRINGING CLEARING SKIES AND DIMINISHING WINDS. WITH PWAT VALUES
FALLING CLOSE TO 0.3 INCHES...FAVORABLE RADIATIONAL COOLING WILL
ALLOW TEMPS TO DROP INTO THE LOWER 30S OVER MUCH OF THE INTERIOR
WEST HALF OF UPPER MI WHERE A FROST ADVISORY WAS ISSUED. FARTHER
EAST...LINGERING NE WINDS WILL BE STRONG ENOUGH TO KEEP TEMPS FROM
DROPPING OFF AS MUCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 414 AM EDT SUN SEP 15 2013
500MB RIDGE AND SFC PRESSURE WILL CONTROL THE FIRST PORTION OF THE
LONG TERM FORECAST PERIOD. THIS RIDGE WILL MOVE FROM THE NORTHERN
PLAINS ON MONDAY MORNING INTO THE OHIO VALLEY BY TUESDAY NIGHT.
EXPECT UPPER MICHIGAN WEATHER TO BE QUITE PLEASANT MONDAY AND
TUESDAY. ON MONDAY 850MB TEMPS WILL DIP TO AROUND 3-5C...AND WINDS
WILL BE NORTHERLY OFF LAKE SUPERIOR. KEPT HIGHS IN THE UPPER 50S AND
60S ACCORDINGLY. TUESDAY 850MB TEMPS WILL CLIMB TO THE 6-10C RANGE
AND SFC WINDS WILL SWING TO THE SOUTH...RAISING AFTERNOON HIGHS INTO
THE UPPER 60S AND LOW 70S...WHICH IS NORMAL FOR THIS TIME OF YEAR.
MEANWHILE...A DEEP 500MB LOW PRESSURE TROUGH MAKES ITS WAY ONSHORE
OVER THE NORTHWESTERN UNITED STATES. THE ASSOCIATED SFC LOW DEVELOPS
OVER MONTANA BY TUESDAY AFTERNOON...AND STRONG MOISTURE
TRANSPORT BRINGS PWATS UP TO 160 PERCENT OF NORMAL INTO WESTERN
UPPER MICHIGAN BY 06Z WEDNESDAY. AS THE LOW MOVES EASTWARD INTO THE
DAKOTAS THROUGH WEDNESDAY NIGHT...EXPECT THIS AREA OF STRONGER
MOISTURE ADVECTION TO MOVE EASTWARD THROUGH THE CWA. WITH A WEAK
SHORTWAVE FLATTENING THE EXITING RIDGE...AND AREA OF MOISTURE
ADVECTION FEEL THAT CHANCE TO SLIGHT CHANCE POPS ARE WARRANTED
ACROSS UPPER MICHIGAN FOR TUESDAY NIGHT AND WEDNESDAY-WITH HIGHER
POPS LOCATED FURTHER SOUTH NEAR THE BETTER FORCING. THE BEST
INSTABILITY ARRIVES LATER WEDNESDAY MORNING INTO THE AFTERNOON...SO
LEFT THUNDER OUT UNTIL THESE TIMES.
THURSDAY INTO SUNDAY WE DEAL WITH THE ARRIVAL OF THE ACTUAL
SFC/UPPER LEVEL LOW PRESSURE SYSTEM...WHICH MODELS CURRENTLY HAVE
TRAVERSING ACROSS THE UPPER GREAT LAKES. AS USUAL...MODEL
DIFFERENCES WILL GREATLY IMPACT THE FORECAST FOR THE WEEKEND...WITH
THE ECMWF/GEM BRINGING A CUT OFF 500MB LOW ACROSS NORTHEASTERN
MINNESOTA/NORTHERN ONTARIO BY FRIDAY AFTERNOON. THE GFS HAS A
NEUTRALLY TILTED TROUGH REACHING MINNESOTA AROUND THE SAME
TIME...WITH THE SURFACE LOW OVER ONTARIO JUST SOUTH OF JAMES BAY.
DESPITE DIFFERENCES...CAN AGREE THAT THIS WILL LIKELY BE A SOGGY END
TO THE WEEK...WITH MODELS PROJECTING PWATS 160-210 PERCENT OF
NORMAL. NOT GOING TO GET CUTE WITH THE GRIDS AT THIS POINT...BUT
WILL USE THE WPC DAY 3-7 FRONTS/PRESSURE LOCATIONS AS A GUIDE UNTIL
GREATER CONSISTENCY IS ACHIEVED. THIS PUTS THE SFC LOW DIRECTLY OVER
UPPER MICHIGAN ON FRIDAY MORNING...AND OVER QUEBEC BY SATURDAY
AFTERNOON.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 131 PM EDT SUN SEP 15 2013
EXPECT A GRADUAL TRANSITION TO VFR CONDITIONS LATER THIS
AFTERNOON WITH THE APPROACH OF HIGH PRESSURE AND THE ARRIVAL OF
DRIER AIR. A STEADY N WIND WILL DIMINISH BY THIS EVENING WITH THE
CLOSER APPROACH OF THE HIGH AND LOSS OF OF DAYTIME HEATING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 515 AM EDT SUN SEP 15 2013
NE WINDS UP TO 30 KNOTS TODAY ARE EXPECTED BEHIND A COLD FRONT
MOVING THROUGH LAKE SUPERIOR EARLY THIS MORNING. WINDS WILL DIMINISH
LATE THIS AFTERNOON AND TONIGHT AS HIGH PRESSURE BUILDS INTO THE
AREA. WITH THE HIGH DOMINATING THE REGION MON...WINDS WILL REMAIN
BELOW 20 KNOTS. AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO
20 KNOTS ARE EXPECTED FROM TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY FROM 2 AM EDT /1 AM CDT/ TO 9 AM EDT /8 AM CDT/
MONDAY FOR MIZ002-004-005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1243 PM CDT SUN SEP 15 2013
.UPDATE...
ISSUED AT 1015 AM CDT SUN SEP 15 2013
THE FORECAST WAS UPDATED THROUGH THIS EVENING TO REFLECT THE
LATEST CLOUD COVER AND WIND TRENDS. I INCREASED CLOUD COVER TODAY
TO HAVE THE CLOUDS CLEARING MUCH SLOWER THAN THE PREVIOUS
FORECAST. THE LATEST HRRR AND RAP13 RUNS INDICATE THE CLOUDS WILL
TAKE A WHILE TO CLEAR...WITH THE COOL NORTHERLY FLOW AND LOW
CONVECTIVE TEMPERATURES BOLSTERING THE CLOUD COVER UNTIL MID TO
LATE AFTERNOON.
I GAVE THE SOUTH SHORE OF WISCONSIN LOW CHANCES OF RAIN SHOWERS
DUE TO THE STRONG NE WINDS OFF LAKE SUPERIOR THROUGH EARLY THIS
AFTERNOON.
I WILL LOOK MORE INTO THE THREAT OF FROST AND FREEZING
TEMPERATURES TONIGHT THIS AFTERNOON.
UPDATE ISSUED AT 645 AM CDT SUN SEP 15 2013
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
A COLD FRONT WILL PUSH ACROSS THE NORTHLAND THIS MORNING...EXITING
TO THE SOUTH BY THE AFTERNOON. LINGERING SPRINKLES/AREAS OF DRIZZLE
AND GUSTY NORTHEAST WINDS WILL ACCOMPANY THE FRONTAL PASSAGE THIS
MORNING. HIGH PRESSURE WILL BUILD INTO THE THE NORTHLAND FROM CANADA
THROUGH THE AFTERNOON...BRINGING GRADUALLY CLEARING SKIES AND
DIMINISHING WIND GUSTS. THE HIGH PRESSURE WILL SETTLE OVER THE
WESTERN LAKE SUPERIOR REGION TONIGHT...ALLOWING FOR CALM WINDS CLEAR
SKIES AND STRONG RADIATIONAL COOLING. LATEST MOS GUIDANCE CONTINUES
TO SHOW MOST LOCATIONS IN THE NORTHLAND SEE LOWS IN THE 30-35 DEGREE
RANGE TONIGHT. LOCALLY COOLER READINGS WILL BE FOUND ACROSS THE
IRON RANGE AS WELL AS IN THE HIGHER TERRAIN OF THE MINNESOTA
ARROWHEAD. WARMER READINGS OF 35-40 DEGREES WILL PREVAIL NEAR
LAKE SUPERIOR...AS WELL AS IN THE BRAINERD LAKES AREA. A FROST
ADVISORY FOR THE OVERNIGHT PERIOD WILL BE ISSUED WITH THE MORNING
FORECAST PACKAGE FOR ALL OF THE DLH ZONES EXCEPT CASS AND CROW
WING COUNTIES. THERE IS A POTENTIAL THAT THE FAR NORTHERN ZONES
WILL NEED TO BE UPGRADED TO A FREEZE WARNING IF DEW POINTS FALL
FAR ENOUGH WITH AFTERNOON MIXING TO ALLOW TEMPERATURES TO REACH
THE MID-UPPER 20S FOR A FEW HOURS OVERNIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN SEP 15 2013
QUIET WEATHER CONDITIONS TO START THE EXTENDED PERIOD AS HIGH
PRESSURE OVER THE GREAT LAKES AND AN UPPER RIDGE OVER THE MIDWEST
KEEP SKIES MOSTLY CLEAR AND THE WX DRY. LOW TEMPS TUE MORNING WILL
BE COOL...INTO THE MID 30S TO MID 40S...BUT QUICKLY WARM INTO THE
UPPER 60S AND LOWER 70S UNDER A WAA REGIME AND MOSTLY SUNNY SKIES
THROUGH TUESDAY. STRONG MIXING WILL ALLOW WINDS TO BECOME GUSTY IN
THE AFTERNOON...UP TO 20-25 MPH AT TIMES. AN UPPER TROUGH AND
ASSOCIATED SFC TROUGH/WARM FRONT WILL TRANSLATE E/NEWD ACROSS THE
NRN/CONTROL PLAINS TUE AFTERNOON AND MOVE INTO SRN AND CNTRL MN BY TUE
EVENING. THIS SYSTEM WILL INCREASE CLOUD COVER FROM SOUTH TO NORTH
DURING THE DAY...AND EVENTUALLY BRING IN CHANCES FOR RAIN SHOWERS
AND THUNDERSTORMS TUE NIGHT. THERE STILL EXIST SOME UNCERTAINTY WITH
THE TRACK OF THE SFC LOW AND THE TIMING OF A SECONDARY UPPER S/W
EXPECTED TO DRIVE EWD FROM MT THROUGH ND AND INTO NRN MN SOME TIME
BETWEEN WED AFTERNOON AND EARLY FRI MORNING. COULD SEE A WARM
SECTOR...POSSIBLY CAPPED...DEVELOP WED AFTERNOON PRIOR TO THE
PASSAGE OF AN EWD PROGRESSING COLD FRONT. SO...KEPT WITH LOWER CHC
POPS WED...AND AN INCREASE WED NIGHT THROUGH THUR EVENING. WHICH
WILL ALSO BE THE MOST FAVORABLE TIME FOR STRONG CONVECTION AND
THUNDERSTORMS.
AS THIS FAIRLY POTENT UPPER LOW TRACKS EWD ACROSS SRN MANITOBA AND
WRN ONTARIO...COLD CANADIAN AIR WILL BE DRAWN SWD INTO THE SYSTEM
AND FILTER INTO SECTIONS OF THE NORTHLAND. AFTER THE FAIRLY MILD
TEMPS WED AND THUR...CONDITIONS WILL BECOME RATHER COOL FRI AND SAT
WITH THIS SYSTEM...WITH HIGHS IN THE 50S AND 60S...AND OVERNIGHT
LOWS IN THE UPPER 30S AND LOWER 40S. WILL LIKELY SEE A FEW CAA
SHOWERS FRI AND SAT DURING THE AFTERNOON...WITH POSSIBLY SOME
CLEARING AND DRYING AT NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1236 PM CDT SUN SEP 15 2013
LARGE CANOPY OF LOW CLOUDS WILL GRDUALLY CLEAR FROM NORTH TO SOUTH
THIS AFTERNOON. IFR AT KDLH SHOULD LIFT TO MVFR BY MID AFTN.
EXPECT VFR OVERNIGHT EXCEPT FOR POTENTIAL BRIEF WINDOW OF BR AT ALL
SITES. CONFIDENCE IS NOT HIGH AT THIS POINT SO ONLY INCLUDED AT
KHIB/KBRD/KHYR.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 38 62 42 / 20 0 0 0
INL 59 30 66 39 / 0 0 0 0
BRD 63 36 65 45 / 10 0 0 0
HYR 60 30 64 38 / 20 0 0 0
ASX 57 34 63 39 / 40 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
MNZ010>012-018>021-026-035>038.
WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM CDT MONDAY FOR
WIZ001>004-006>009.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
140>148.
&&
$$
UPDATE...GROCHOCINSKI
SHORT TERM...GRANING
LONG TERM...BJT
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
351 PM EDT SUN SEP 15 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT INTO MONDAY
MORNING WITH SCATTERED TO NUMEROUS SHOWERS. BEHIND THIS FRONT MUCH
COOLER AIR WILL FILTER INTO THE REGION WITH A WIDESPREAD FROST OR
FREEZING CONDITIONS EXPECTED AWAY FROM LAKE CHAMPLAIN MONDAY NIGHT.
THEREAFTER...LARGE SURFACE HIGH PRESSURE WILL BRING FAIR WEATHER
AND GRADUALLY WARMING TEMPERATURES TO THE AREA THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 330 PM EDT SUNDAY...FORECAST REMAINS IN GOOD SHAPE AS WE
PROGRESS INTO THE EVENING AND OVERNIGHT HOURS. STILL WATCHING A
STRONG EARLY SEASON COLD FRONT PROGRESSING STEADILY SOUTH AND EAST
TOWARD OUR AREA FROM SOUTH CENTRAL CANADA AND PER CURRENT
OBSERVATIONAL TRENDS EXPECT THE BOUNDARY TO ENTER OUR NORTHERN
ZONES LATER THIS EVENING AND PROGRESS FURTHER SOUTH THROUGH THE
OVERNIGHT/EARLY MORNING HOURS. DECENT FRONTAL ZONE CONVERGENCE
ALONG WITH A NARROW PWAT AXIS OF AROUND 1 INCH BOOSTS CONFIDENCE
THAT MOST OF OUR CENTRAL AND NORTHERN COUNTIES WILL SEE
MEASUREABLE LIGHT PCPN WITH THE PASSAGE OF THIS FEATURE. THUS HAVE
BOOSTED POPS INTO THE SOLID LIKELY (60-70%)...TO LOW END
CATEGORICAL RANGE (~80%) IN THE CASE OF THE NRN MTNS LATER TONIGHT
THROUGH MID-MORNING ON MONDAY. POPS LESS ACROSS THE SOUTH AS THE
FRONT ARRIVES LATER AND EVIDENCE THAT AFORMENTIONED LOW LEVEL
CONVERGENCE WILL WEAKEN AS THE BOUNDARY PRESSES SOUTH. AS
MENTIONED YESTERDAY...LOWS A BIT TRICKY GIVEN FRONTAL PASSAGE WILL
OCCUR WITHIN A FEW HOURS OF SUNRISE AND AMBIENT CLOUD COVER WILL
ACT TO INITIALLY OFFSET STRONGER COLD THERMAL ADVECTION. THUS A
BLEND OF AVAILABLE GUIDANCE ALONG WITH BIAS-CORRECTION STILL
APPEARS THE MOST REASONABLE COURSE OFFERING MINS FROM THE MID 40S
THE LOWER 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM EDT SUNDAY...SHOWERS TO THEN END NORTH TO SOUTH
THROUGH THE MORNING HOURS ON MONDAY AS SFC FRONT QUICKLY CLEARS
SOUTH AND EAST OF OUR AREA. LINGERING POST-FRONTAL MOISTURE AND
BLOCKED LOW TO MID LEVEL FLOW SHOULD ENSURE COLD THERMAL ADVECTION
STRATOCUMULUS SHOULD PERSIST ACROSS MUCH OF THE AREA AT LEAST INTO
THE EARLY TO MID AFTERNOON HOURS BEFORE PARTIAL SUN DEVELOPS LATE.
BLENDED MODEL MEAN 850 MB TEMPERATURES FALL SLOWLY BUT STEADILY
THROUGH THE DAY TO AROUND 0C BY EARLY EVENING AND WITH MODESTLY
GUSTY NORTHWESTELY FLOW THERE WILL DEFINITELY BE A FALL-LIKE CHILL
IN THE AIR. GIVEN THESE FACTORS HAVE LEANED ON THE COLDER SIDE OF
AVBL TEMPERATURE GUIDANCE SHOWING READINGS CLIMBING ONLY SOME 3 TO
7 DEGREES ABOVE OVERNIGHT LOWS...OR TOPPING OUT MAINLY IN THE 50S.
A FEW SPOTS IN THE NORTHERN MOUNTAINS MAY STRUGGLE TO HIT 50 WHILE
AFTERNOON DOWNSLOPE FLOW SHOULD PUSH SOME LOCALES ACROSS
SOUTHEASTERN VT INTO THE LOWER 60S.
SKIES THEN GRADUALLY TREND CLEAR BY MONDAY NIGHT AS WINDS SLOWLY
RELAX AND STRONG 1030 HPA CANADIAN HIGH PRESSURE BUILDS INTO THE
REGION. WITH IDEAL RADIATIVE EFFECTS EXPECTED...WIDESPREAD FROSTY TO
FREEZING CONDITIONS ARE EXPECTED IN MOST AREAS AWAY FROM LAKE
CHAMPLAIN. NO HEADLINES WITH THIS PACKAGE...BUT CONFIDENCE IS HIGH
THAT THE GROWING SEASON WILL END FOR MANY BY TUESDAY MORNING. IN
FACT A FEW SPOTS MAY APPROACH RECORD LOWS FOR THE DATE...NOT A
TOPIC DISCUSSED IN OUR AREA TOO OFTEN THESE DAYS. PATCHY FOG ALSO A
GOOD BET HERE AND THERE...ESP IN THE MILDER LOCATIONS.
THEREAFTER...DEEP LAYER HIGH PRESSURE SLOWLY SETTLES ACROSS THE
REGION WITH FAIR AND SEASONABLY COOL WEATHER FOR TUESDAY INTO
TUESDAY NIGHT. STILL COULD SEE SOME PATCHY FROST/FOG BY EARLY
WEDNESDAY MORNING...ESP IN THE NORTHERN MTN HOLLOWS...BUT DEVELOPING
LIGHT RETURN FLOW LATER AT NIGHT SHOULD HOLD TEMPERATURES UP A FEW
THAN 24 HOURS PRIOR.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 350 PM EDT SUNDAY...MUCH BETTER AGREEMENT WITH LARGE SCALE
PATTERN FOR LATE WEEK INTO NEXT WEEKEND ASSOCIATED WITH DEVELOPMENT
OF MID/UPPER LVL AND TRACKING OF SFC COLD FRNT.
OVERALL...ECMWF/GEM HAS TRENDED TWD THE GFS WITH A
FAST/PROGRESSIVE MID/UPPER LVL PATTERN...WITH GREATEST THREAT OF
SHOWERS ON SATURDAY. THE 12Z ECMWF STILL SUPPORTS THE POTENTIAL
FOR A FEW LIGHT RAIN SHOWERS ASSOCIATED WITH A SFC WARM FRNT LATE
FRIDAY...AS PRE FRONTAL VORT INTERACTS WITH SOME 850 TO 500MB RH.
HOWEVER...THINKING INITIAL SURGE OF MOISTURE WL DISSIPATE AS IT
ENCOUNTERS DEEP DRY LAYER ASSOCIATED WITH STRONG MID/UPPER LVL
RIDGE ACRS THE EASTERN CONUS. WL KEEP FRIDAY DRY ATTM...AND
MENTION HIGHEST CHC POPS ON SATURDAY/SATURDAY NIGHT. BOTH
GFS/ECMWF SHOW A NARROW RIBBON OF ENHANCED 850 TO 500MB RH...ALONG
WITH FAVORABLE LIFT...RESULTING IN ONLY A BRIEF 3 TO 6 HOUR WINDOW
OF SHOWERS.
OTHERWISE...WEDS THRU FRIDAY OF THIS UPCOMING WEEK WL
BE DRY WITH RIDGE OF HIGH PRES DOMINATING ACRS THE NE CONUS.
PROGGED 85H TEMPS START BTWN 4-6C ON WEDS...BUT WARM TO 11-13C BY
18Z SATURDAY...SUPPORTING A TREND OF ABOVE NORMAL TEMPS BY LATE
WEEK INTO NEXT WEEKEND. GIVEN THE WARM THERMAL PROFILES WL TREND
TEMPS ABOVE NORMAL WITH VALUES BACK INTO THE 70S...MAYBE NEAR 80
IN THE WARMER VALLEYS BY SATURDAY...DEPENDING UPON CLOUD COVER.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...CRNT SFC ANALYSIS PLACES A COLD FRNT ACRS
CENTRAL CANADA INTO THE CENTRAL GREAT LAKES ATTM...WITH GENERAL
MOVEMENT TWD THE EAST. THIS FRNT WL PRODUCE A 2 TO 6 HR WINDOW OF
-SHRA...ALONG WITH A POTENTIAL PERIOD OF MVFR/IFR CIGS ON MONDAY
MORNING...ESPECIALLY AT SLK/MPV. LOCAL HI RES MODEL REFLECTIVITY
AND LATEST 15Z RAP REFLECTIVITY PROGGS SHOW INITIAL BAND OF PRECIP
WL FALL MAINLY AS VIRGA THIS EVENING...DUE TO VERY DRY LLVLS...BUT
EXPECT -SHRA WITH NO VIS RESTRICTIONS TO DEVELOP AT MSS BY
01Z...AND INTO THE CPV BY 04Z...AND INTO AFT MIDNIGHT. GIVEN
UPSTREAM OBS OF IFR CONDITIONS BEHIND THE SFC FRNT...EXPECT A
PERIOD OF POST FRONTAL LOW CLOUDS/BR/-RA BTWN 10Z-16Z
MONDAY...WITH PERIODS OF IFR LIKELY...ESPECIALLY AT MPV/SLK. THE
COMBINATION OF UPSLOPE FLW...LEFTOVER SFC TO 850MB MOISTURE BEHIND
THE BOUNDARY...AND UPSTREAM OBS SUPPORTS THIS POTENTIAL.
OTHERWISE...SOUTH/SOUTHWEST WINDS WL SHIFT TO THE NORTH/NORTHWEST
BTWN 04-10Z TONIGHT...AND SLOWLY TO THE NORTHEAST BY MIDDAY MONDAY
AS SFC HIGH PRES BUILDS OUR TAF SITES.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...ANY LINGERING STRATUS DECK BTWN
1500 AND 3000 KFT WL SLOWLY LIFT MONDAY AFTN...AS NORTH WINDS
ADVECT DRIER AIR INTO OUR TAF SITES. SFC HIGH PRES WL RESULT IN
VFR CONDITIONS FOR TUES THROUGH THURSDAY...WITH THE EXCEPTION OF
DAILY MORNING FOG AND LIFR CONDITION AT SLK/MPV. FOG COULD BE
WIDESPREAD ON TUESDAY MORNING...GIVEN LIGHT WINDS AND CLR SKIES
WITH AREAS OF FREEZING FOG POSSIBLE AT SLK/MPV. CLOUDS AND THE
THREAT OF SHOWERS INCREASES ON FRIDAY ASSOCIATED WITH OUR NEXT
SYSTEM...BUT VFR CONDITIONS SHOULD PREVAIL.
&&
.CLIMATE...
BELOW ARE RECORD LOW TEMPERATURES FOR TUESDAY SEPTEMBER 17.
LOCN RECORD DATE
KBTV 34F 1961
KMPV 29F 1948
KMSS 30F 1973
K1V4 29F 1959
&&
.EQUIPMENT...
AS OF 330 PM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS ARE ORDERED
AND THE REPAIR WORK HAS BEEN SCHEDULED FOR SEPTEMBER 17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...TABER
AVIATION...TABER
CLIMATE...JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
330 PM EDT SUN SEP 15 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT INTO MONDAY
MORNING WITH SCATTERED TO NUMEROUS SHOWERS. BEHIND THIS FRONT MUCH
COOLER AIR WILL FILTER INTO THE REGION WITH A WIDESPREAD FROST OR
FREEZING CONDITIONS EXPECTED AWAY FROM LAKE CHAMPLAIN MONDAY NIGHT.
THEREAFTER...LARGE SURFACE HIGH PRESSURE WILL BRING FAIR WEATHER
AND GRADUALLY WARMING TEMPERATURES TO THE AREA THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 330 PM EDT SUNDAY...FORECAST REMAINS IN GOOD SHAPE AS WE
PROGRESS INTO THE EVENING AND OVERNIGHT HOURS. STILL WATCHING A
STRONG EARLY SEASON COLD FRONT PROGRESSING STEADILY SOUTH AND EAST
TOWARD OUR AREA FROM SOUTH CENTRAL CANADA AND PER CURRENT
OBSERVATIONAL TRENDS EXPECT THE BOUNDARY TO ENTER OUR NORTHERN
ZONES LATER THIS EVENING AND PROGRESS FURTHER SOUTH THROUGH THE
OVERNIGHT/EARLY MORNING HOURS. DECENT FRONTAL ZONE CONVERGENCE
ALONG WITH A NARROW PWAT AXIS OF AROUND 1 INCH BOOSTS CONFIDENCE
THAT MOST OF OUR CENTRAL AND NORTHERN COUNTIES WILL SEE
MEASUREABLE LIGHT PCPN WITH THE PASSAGE OF THIS FEATURE. THUS HAVE
BOOSTED POPS INTO THE SOLID LIKELY (60-70%)...TO LOW END
CATEGORICAL RANGE (~80%) IN THE CASE OF THE NRN MTNS LATER TONIGHT
THROUGH MID-MORNING ON MONDAY. POPS LESS ACROSS THE SOUTH AS THE
FRONT ARRIVES LATER AND EVIDENCE THAT AFORMENTIONED LOW LEVEL
CONVERGENCE WILL WEAKEN AS THE BOUNDARY PRESSES SOUTH. AS
MENTIONED YESTERDAY...LOWS A BIT TRICKY GIVEN FRONTAL PASSAGE WILL
OCCUR WITHIN A FEW HOURS OF SUNRISE AND AMBIENT CLOUD COVER WILL
ACT TO INITIALLY OFFSET STRONGER COLD THERMAL ADVECTION. THUS A
BLEND OF AVAILABLE GUIDANCE ALONG WITH BIAS-CORRECTION STILL
APPEARS THE MOST REASONABLE COURSE OFFERING MINS FROM THE MID 40S
THE LOWER 50S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM EDT SUNDAY...SHOWERS TO THEN END NORTH TO SOUTH
THROUGH THE MORNING HOURS ON MONDAY AS SFC FRONT QUICKLY CLEARS
SOUTH AND EAST OF OUR AREA. LINGERING POST-FRONTAL MOISTURE AND
BLOCKED LOW TO MID LEVEL FLOW SHOULD ENSURE COLD THERMAL ADVECTION
STRATOCUMULUS SHOULD PERSIST ACROSS MUCH OF THE AREA AT LEAST INTO
THE EARLY TO MID AFTERNOON HOURS BEFORE PARTIAL SUN DEVELOPS LATE.
BLENDED MODEL MEAN 850 MB TEMPERATURES FALL SLOWLY BUT STEADILY
THROUGH THE DAY TO AROUND 0C BY EARLY EVENING AND WITH MODESTLY
GUSTY NORTHWESTELY FLOW THERE WILL DEFINITELY BE A FALL-LIKE CHILL
IN THE AIR. GIVEN THESE FACTORS HAVE LEANED ON THE COLDER SIDE OF
AVBL TEMPERATURE GUIDANCE SHOWING READINGS CLIMBING ONLY SOME 3 TO
7 DEGREES ABOVE OVERNIGHT LOWS...OR TOPPING OUT MAINLY IN THE 50S.
A FEW SPOTS IN THE NORTHERN MOUNTAINS MAY STRUGGLE TO HIT 50 WHILE
AFTERNOON DOWNSLOPE FLOW SHOULD PUSH SOME LOCALES ACROSS
SOUTHEASTERN VT INTO THE LOWER 60S.
SKIES THEN GRADUALLY TREND CLEAR BY MONDAY NIGHT AS WINDS SLOWLY
RELAX AND STRONG 1030 HPA CANADIAN HIGH PRESSURE BUILDS INTO THE
REGION. WITH IDEAL RADIATIVE EFFECTS EXPECTED...WIDESPREAD FROSTY TO
FREEZING CONDITIONS ARE EXPECTED IN MOST AREAS AWAY FROM LAKE
CHAMPLAIN. NO HEADLINES WITH THIS PACKAGE...BUT CONFIDENCE IS HIGH
THAT THE GROWING SEASON WILL END FOR MANY BY TUESDAY MORNING. IN
FACT A FEW SPOTS MAY APPROACH RECORD LOWS FOR THE DATE...NOT A
TOPIC DISCUSSED IN OUR AREA TOO OFTEN THESE DAYS. PATCHY FOG ALSO A
GOOD BET HERE AND THERE...ESP IN THE MILDER LOCATIONS.
THEREAFTER...DEEP LAYER HIGH PRESSURE SLOWLY SETTLES ACROSS THE
REGION WITH FAIR AND SEASONABLY COOL WEATHER FOR TUESDAY INTO
TUESDAY NIGHT. STILL COULD SEE SOME PATCHY FROST/FOG BY EARLY
WEDNESDAY MORNING...ESP IN THE NORTHERN MTN HOLLOWS...BUT DEVELOPING
LIGHT RETURN FLOW LATER AT NIGHT SHOULD HOLD TEMPERATURES UP A FEW
THAN 24 HOURS PRIOR.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 331 AM EDT SUNDAY...DEEP-LAYER RIDGE FIRMLY ESTABLISHED
ACROSS THE NORTHEAST CONUS BRINGS DRY AND QUIET WEATHER TO START
THE PERIOD RIGHT THRU THURSDAY NIGHT. AIR MASS GRADUALLY MODERATES
THRU THE PERIOD...WITH VALLEY HIGHS NEAR 70F ON WEDNESDAY AND INTO
THE LOW-MID 70S FOR THURSDAY AND FRIDAY. COULD SEE SOME PATCHY
VALLEY FOG TUESDAY AND WEDNESDAY NIGHT (MAINLY 06-12Z) ASSOCIATED
WITH LIGHT WINDS AND GOOD RADIATIVE COOLING CONDITIONS. SOME
DIFFERENCES BETWEEN THE 00Z ECMWF AND 00Z GFS WITH RESPECT TO
TIMING OF NEXT SHORTWAVE TROUGH FROM THE GREAT LAKES AND
ASSOCIATED WARM FRONT. THE ECMWF IS A BIT QUICKER...SUGGESTING
INCREASING CLOUDS AND DEVELOPING RAIN FRIDAY AFTN ACROSS NRN NY
AND DEVELOPING ACROSS VT FRIDAY NIGHT INTO SATURDAY MORNING. IN
CONTRAST THE 00Z GFS IS ABOUT 24 HOURS SLOWER...DOESN/T SHOW A
WARM FRONT WITH ANY QPF AWAITING ARRIVAL OF A COLD FRONT LATE IN
THE DAY SATURDAY. TOOK A COMPROMISE OF THE TWO SOLNS IN DERIVING
SKY/POPS. LOOKING AT A SLIGHT CHANCE OF -SHRA ACROSS THE ST.
LAWRENCE VALLEY FRIDAY AFTN...FOLLOWED BY 30-40 POPS AREAWIDE
FRIDAY NIGHT INTO SATURDAY. TEMPERATURE FORECAST GENERAL FOLLOWS A
50/50 BLEND OF MEX-MOS VALUES AND 14-DAY BIAS CORRECTION OF MEX-
MOS AND RESULTANT FORECAST IS ABOVE SEASONAL AVERAGES FOR MID-
SEPT.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...CRNT SFC ANALYSIS PLACES A COLD FRNT ACRS
CENTRAL CANADA INTO THE CENTRAL GREAT LAKES ATTM...WITH GENERAL
MOVEMENT TWD THE EAST. THIS FRNT WL PRODUCE A 2 TO 6 HR WINDOW OF
-SHRA...ALONG WITH A POTENTIAL PERIOD OF MVFR/IFR CIGS ON MONDAY
MORNING...ESPECIALLY AT SLK/MPV. LOCAL HI RES MODEL REFLECTIVITY
AND LATEST 15Z RAP REFLECTIVITY PROGGS SHOW INITIAL BAND OF PRECIP
WL FALL MAINLY AS VIRGA THIS EVENING...DUE TO VERY DRY LLVLS...BUT
EXPECT -SHRA WITH NO VIS RESTRICTIONS TO DEVELOP AT MSS BY
01Z...AND INTO THE CPV BY 04Z...AND INTO AFT MIDNIGHT. GIVEN
UPSTREAM OBS OF IFR CONDITIONS BEHIND THE SFC FRNT...EXPECT A
PERIOD OF POST FRONTAL LOW CLOUDS/BR/-RA BTWN 10Z-16Z
MONDAY...WITH PERIODS OF IFR LIKELY...ESPECIALLY AT MPV/SLK. THE
COMBINATION OF UPSLOPE FLW...LEFTOVER SFC TO 850MB MOISTURE BEHIND
THE BOUNDARY...AND UPSTREAM OBS SUPPORTS THIS POTENTIAL.
OTHERWISE...SOUTH/SOUTHWEST WINDS WL SHIFT TO THE NORTH/NORTHWEST
BTWN 04-10Z TONIGHT...AND SLOWLY TO THE NORTHEAST BY MIDDAY MONDAY
AS SFC HIGH PRES BUILDS OUR TAF SITES.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...ANY LINGERING STRATUS DECK BTWN
1500 AND 3000 KFT WL SLOWLY LIFT MONDAY AFTN...AS NORTH WINDS
ADVECT DRIER AIR INTO OUR TAF SITES. SFC HIGH PRES WL RESULT IN
VFR CONDITIONS FOR TUES THROUGH THURSDAY...WITH THE EXCEPTION OF
DAILY MORNING FOG AND LIFR CONDITION AT SLK/MPV. FOG COULD BE
WIDESPREAD ON TUESDAY MORNING...GIVEN LIGHT WINDS AND CLR SKIES
WITH AREAS OF FREEZING FOG POSSIBLE AT SLK/MPV. CLOUDS AND THE
THREAT OF SHOWERS INCREASES ON FRIDAY ASSOCIATED WITH OUR NEXT
SYSTEM...BUT VFR CONDITIONS SHOULD PREVAIL.
&&
.CLIMATE...
BELOW ARE RECORD LOW TEMPERATURES FOR TUESDAY SEPTEMBER 17.
LOCN RECORD DATE
KBTV 34F 1961
KMPV 29F 1948
KMSS 30F 1973
K1V4 29F 1959
&&
.EQUIPMENT...
AS OF 330 PM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS ARE ORDERED
AND THE REPAIR WORK HAS BEEN SCHEDULED FOR SEPTEMBER 17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...BANACOS
AVIATION...TABER
CLIMATE...JMG
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
127 PM EDT SUN SEP 15 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE NORTHEAST REGION WILL GIVE WAY TO A
FRONTAL BOUNDARY LATER TONIGHT INTO MONDAY. PRECIPITATION WILL
TAPER OFF DURING THE AFTERNOON HOURS MONDAY...GIVING WAY TO HIGH
PRESSURE THROUGH THE END OF THE WEEK...BEFORE ANOTHER FRONT ARRIVAL
LATE FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1025 AM EDT SUNDAY...INHERITED FORECAST MORE OR LESS ON TRACK
AS OF LATE MORNING WITH ONLY MINOR TWEAKS TO SKY COVER NEEDED TO
MATCH CURRENT OBSERVATIONAL TRENDS. GENERALLY TRENDING PTLY SUNNY
FOR MOST AREAS TODAY UNDER INCREASING MID/HIGH LVL RH...THOUGH
THICKER CLOUD COVER LIKELY ACROSS THE SLV BY THIS AFTERNOON. SOME
GUSTY SOUTH/SOUTHWESTERLY FLOW ALSO LIKELY FROM THE CHVLY
WESTBOUND AS P-GRAD SLOWLY TIGHTENS BETWEEN DEPARTING SFC HIGH AND
APPROACHING COLD FRONT OFF TO OUR DISTANT NW (GUSTING TO 18 KT AT
KBTV). MODEL SOUNDINGS AND 925 MB THERMAL PROFILES SUPPORT HIGHS
MAINLY IN THE 60S TO AROUND 70 WHICH IS COVERED WELL AT THIS POINT
SO NO CHANGES NEEDED IN THAT REGARD. HAVE A GREAT DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 435 AM EDT SUNDAY...CLD COVER ON THE INCR BY THIS EVENING
AS NEXT FRONT APPROACHES FROM THE GREAT LKS REGION. MDLS CONTINUE
TO SHOW SLOW ONSET OF RAIN INTO THE AREA GOING INTO THE OVERNGT
HRS...AIDED BY SFC HIGH TO OUR SOUTH AND EAST BLOCKING ADVANCE
INITIALLY. MDLS DO BRING FRONT THRU THE CWA...BRINGING HIGHEST
POPS AFT 06Z MONDAY. WILL CONTINUE CURRENT TREND OF TAPERING -RW
OFF TOWARDS 12Z MONDAY FROM THE NW. OVERNGT LOWS WILL REMAIN
FAIRLY STABLE WITH LITTLE DROP DUE TO CLDS FROM FRNT.
FIRST HALF OF MONDAY WILL HAVE THE CWA CONTINUE TO SEE -RW FROM
EXITING FRNTL BOUNDARY WHICH WILL EXIT TO OUR SE BY THE AFTNOON
HRS. OVERALL QPF FROM FROPA AROUND 0.10-0.20". CLRING EXPECTED
FROM NW TO SE AS A RESULT WITH SFC HIGH PRESSURE EAST FROM THE
GREAT LKS REGION. CAA BROUGHT DOWN FROM NNW WINDS 10-20 MPH AHEAD
OF THE APPROACHING RIDGE WILL AID TO DROP OVERNGT LOWS MON NGT TO
MAINLY IN THE 30S W/ SOME 20S IN HIR ELEV. WITH CLR SKIES...CALM
WINDS ACCOMPANYING THIS CD AIRMASS...EXPECTING MANY SPOTS TO SEE
PATCHY/AREAS OF FROST MAINLY AFT 06Z TUES WHEN MDLS BRING RIDGE
CRESTING OVER MOST OF CWA. NO HEADLINES ISSUED ATTM FOR FROST
ADVISORY BUT MAY BE ISSUED LATER TODAY. CD NIGHT MONDAY WILL GIVE
WAY TO A GREAT SUNNY DAY ON TUESDAY AS SFC RIDGE PUSHES OFF THE
NEW ENGLAND COAST. BULK OF WAA ON SSW FLOW REMAINS JUST OFF TO OUR
WEST IN THE GREAT LKS REGION...SO WILL KEEP HIGH TEMPS MAINLY IN
THE 60S...WHICH WILL BE BLW NORMAL FOR MANY LOCALES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 331 AM EDT SUNDAY...DEEP-LAYER RIDGE FIRMLY ESTABLISHED
ACROSS THE NORTHEAST CONUS BRINGS DRY AND QUIET WEATHER TO START
THE PERIOD RIGHT THRU THURSDAY NIGHT. AIR MASS GRADUALLY MODERATES
THRU THE PERIOD...WITH VALLEY HIGHS NEAR 70F ON WEDNESDAY AND INTO
THE LOW-MID 70S FOR THURSDAY AND FRIDAY. COULD SEE SOME PATCHY
VALLEY FOG TUESDAY AND WEDNESDAY NIGHT (MAINLY 06-12Z) ASSOCIATED
WITH LIGHT WINDS AND GOOD RADIATIVE COOLING CONDITIONS. SOME
DIFFERENCES BETWEEN THE 00Z ECMWF AND 00Z GFS WITH RESPECT TO
TIMING OF NEXT SHORTWAVE TROUGH FROM THE GREAT LAKES AND
ASSOCIATED WARM FRONT. THE ECMWF IS A BIT QUICKER...SUGGESTING
INCREASING CLOUDS AND DEVELOPING RAIN FRIDAY AFTN ACROSS NRN NY
AND DEVELOPING ACROSS VT FRIDAY NIGHT INTO SATURDAY MORNING. IN
CONTRAST THE 00Z GFS IS ABOUT 24 HOURS SLOWER...DOESN/T SHOW A
WARM FRONT WITH ANY QPF AWAITING ARRIVAL OF A COLD FRONT LATE IN
THE DAY SATURDAY. TOOK A COMPROMISE OF THE TWO SOLNS IN DERIVING
SKY/POPS. LOOKING AT A SLIGHT CHANCE OF -SHRA ACROSS THE ST.
LAWRENCE VALLEY FRIDAY AFTN...FOLLOWED BY 30-40 POPS AREAWIDE
FRIDAY NIGHT INTO SATURDAY. TEMPERATURE FORECAST GENERAL FOLLOWS A
50/50 BLEND OF MEX-MOS VALUES AND 14-DAY BIAS CORRECTION OF MEX-
MOS AND RESULTANT FORECAST IS ABOVE SEASONAL AVERAGES FOR MID-
SEPT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...CRNT SFC ANALYSIS PLACES A COLD FRNT ACRS
CENTRAL CANADA INTO THE CENTRAL GREAT LAKES ATTM...WITH GENERAL
MOVEMENT TWD THE EAST. THIS FRNT WL PRODUCE A 2 TO 6 HR WINDOW OF
-SHRA...ALONG WITH A POTENTIAL PERIOD OF MVFR/IFR CIGS ON MONDAY
MORNING...ESPECIALLY AT SLK/MPV. LOCAL HI RES MODEL REFLECTIVITY
AND LATEST 15Z RAP REFLECTIVITY PROGGS SHOW INITIAL BAND OF PRECIP
WL FALL MAINLY AS VIRGA THIS EVENING...DUE TO VERY DRY LLVLS...BUT
EXPECT -SHRA WITH NO VIS RESTRICTIONS TO DEVELOP AT MSS BY
01Z...AND INTO THE CPV BY 04Z...AND INTO AFT MIDNIGHT. GIVEN
UPSTREAM OBS OF IFR CONDITIONS BEHIND THE SFC FRNT...EXPECT A
PERIOD OF POST FRONTAL LOW CLOUDS/BR/-RA BTWN 10Z-16Z
MONDAY...WITH PERIODS OF IFR LIKELY...ESPECIALLY AT MPV/SLK. THE
COMBINATION OF UPSLOPE FLW...LEFTOVER SFC TO 850MB MOISTURE BEHIND
THE BOUNDARY...AND UPSTREAM OBS SUPPORTS THIS POTENTIAL.
OTHERWISE...SOUTH/SOUTHWEST WINDS WL SHIFT TO THE NORTH/NORTHWEST
BTWN 04-10Z TONIGHT...AND SLOWLY TO THE NORTHEAST BY MIDDAY MONDAY
AS SFC HIGH PRES BUILDS OUR TAF SITES.
OUTLOOK 18Z MONDAY THROUGH FRIDAY...ANY LINGERING STRATUS DECK BTWN
1500 AND 3000 KFT WL SLOWLY LIFT MONDAY AFTN...AS NORTH WINDS
ADVECT DRIER AIR INTO OUR TAF SITES. SFC HIGH PRES WL RESULT IN
VFR CONDITIONS FOR TUES THROUGH THURSDAY...WITH THE EXCEPTION OF
DAILY MORNING FOG AND LIFR CONDITION AT SLK/MPV. FOG COULD BE
WIDESPREAD ON TUESDAY MORNING...GIVEN LIGHT WINDS AND CLR SKIES
WITH AREAS OF FREEZING FOG POSSIBLE AT SLK/MPV. CLOUDS AND THE
THREAT OF SHOWERS INCREASES ON FRIDAY ASSOCIATED WITH OUR NEXT
SYSTEM...BUT VFR CONDITIONS SHOULD PREVAIL.
&&
.EQUIPMENT...
AS OF 435 AM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR DUE TO A DAMAGED ANTENNA. REPLACEMENT PARTS ARE ORDERED
AND THE REPAIR WORK HAS BEEN SCHEDULED FOR SEPTEMBER 17-20.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JN
NEAR TERM...JMG
SHORT TERM...JN
LONG TERM...BANACOS
AVIATION...TABER
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS SPOKANE WA
248 PM PDT Sun Sep 15 2013
.SYNOPSIS...
Widespread showers and thunderstorms will occur over the Pacific
Northwest tonight as a vigorous cold front moves through the
region. Locally heavy rain and gusty winds will be possible this
evening over much of central and eastern Washington. The cold
front will bring an end to the record breaking heat. By Monday,
afternoon temperatures will fall into the 70s. Cooler and
occasionally showery weather is expected to persist through much
of the week.
&&
.DISCUSSION...
Tonight: Clusters of showers and thunderstorms are expected to
traverse the Inland Northwest tonight. We have talked extensively
the last few days about the phasing of two low pressure systems
along the coast and the negatively tilted 500mb trough progged to
move over the region tonight. As of 2PM, thunderstorms were
organizing over Oregon over the high terrain around Burns and also
in the vicinity of a deepening surface low near Pendleton. Surface
based instability (CAPE of 800-1100J/KG per RUC analysis) will
fuel rapid development of storms over Oregon late this afternoon.
Dewpoints around Tri-Cities and Pendleton are in the low to mid
50s. Oregon and south central Washington look to have a good shot
of strong to severe thunderstorms capable of damaging wind and
hail. Further north (central and northeast Washington), the
environment appears to be marginal for sustaining strong
convection. A persistent east wind the last few days has generated
a relatively dry boundary layer. Dewpoints from Sandpoint to
Spokane to Pullman to Wenatchee are generally in the upper 40s.
LAPS and RUC analysis shows very little surface based instability
which may end up being detrimental to sustaining strong storms
this evening. We will monitor the situation closely. As the
surface low near Pendleton kicks northward this evening it is
possible that low level moisture will traverse along with the low
and fuel strong storms along the way. There may also be enough
shear and mid-level instability with the vigorous, negatively
tilted trough to maintain storm organization into Wenatchee, Moses
Lake, Pullman and Spokane.
A Flash Flood Watch remains in effect for the burn scar areas
around Wenatchee, Chelan and Leavenworth through 11 PM. Tonight`s
system is probably not as favorable for flash flooding as others
we have seen this summer. Tonight`s system will be more
progressive and mid-level flow should be strong enough to produce
storm motion of 20-30mph. Yet, with the high mid-level moisture
content of the atmosphere and strong forcing, it is possible that
the burn scars could experience a couple rounds of heavy rain this
evening. Certainly worth heightening awareness of these vulnerable
areas with a watch.
Monday: The cold front will be into western Montana by daybreak on
Monday. Morning showers will linger over northeast Washington and
the Idaho Panhandle under the cold core. Strong mid-level dry
advection should bring a more stable air mass to the Idaho
Panhandle during the afternoon hours and we should see a general
decrease in shower activity through the day. Scattered showers and
thunderstorms will be slower to move out of northeast and north
central Washington around Colville and Republic where mid level
moisture will be slower to evacuate. Fall will arrive behind the
cold front. High temperatures will be much more typical of mid
September on Monday with 70s the rule for most of the Inland
Northwest. /GKoch
Monday night through Thursday morning...The brief break in the
weather early in the week will give way to another trough that
will bring showers and thunderstorms to the Inland Northwest. The
trough will move from southwest to northeast, perhaps lifting
northward a little further east than the current system. As a
result, precipitation chances ramp up during the afternoon on
Tuesday and continue into Wednesday night. The western Columbia
Basin into the Waterville Plateau may miss out on a lot of the
precipitation given the track of the storm. However, if the track
is further to the west then chances for precipitation will
increase. The moisture associated with this system will not be as
great as what we will experience this evening/tonight, but PW
values are going to be about 120 to 140 percent of normal, so some
localized heavier rainfall is possible, especially over far
eastern Washington into the Idaho panhandle. Chances for
precipitation will continue over the eastern higher terrain on
Wednesday with the trough not completely out of the region. But
the clouds and rainfall should clear out by Thursday morning.
Temperatures will be cool for mid- September, with Tuesday and
Wednesday afternoon topping out a few degrees below normal.
A quiet day is in store for Thursday, although it will be a
chilly when you wake up. A transient shortwave ridge will
traverse eastern Washington and the Idaho panhandle. A nice
rebound in temperatures will occur Thursday afternoon, with
readings topping out a few degrees above normal. ty
Thursday Night through Sunday: The short lived ridge will exit to
the east allowing another trough of low pressure to influence the
region. The trough and associated cold front will bring lower
temperatures and another good chance for widespread precipitation
across the region. Friday will bring the warmest and nicest day
of the period with strong SW flow ahead of the frontal system that
will push temperatures a handful of degrees above normal. Winds on
Friday will also be mostly terrain driven and remain light.
Friday afternoon is when the system will reach the Cascades
bringing increased precipitation chances. Overnight Friday into
Saturday the remainder of the region will stand the best chance
for precipitation. For right now the areas that will receive the
most rainfall from the system will be the Cascades along with the
NE Washington and ID Panhandle Mountains. The Basin currently
still remains questionable as models are wanting to shadow this
area. I went ahead and added slight chance of thunder for Saturday
based on weak CAPE values and due to the passage of the low center
over the region during this time frame.
Winds will be on the rise once again with the passage of the
front and then also with post frontal winds. Strongest winds look
to be on Saturday afternoon and evening. This system will likely
have some similarities with the system passing today and tomorrow.
Temperatures with the frontal passage will dip back below normal
remaining in the 60s and low 70s for most over the weekend.
Models then hint at another flat ridge after the trough exits to
the east which would bring lower chances for precipitation before
another system takes aim at the region for next week. /Fliehman
&&
.AVIATION...
18Z TAFS: A vigorous cold front will produce showers and
thunderstorms from late this afternoon through Monday morning. The
12z GFS is preferred for the general timing of the convection over
eastern Washington and north Idaho. Gusty outflow winds and brief
heavy rains will accompany the strongest cells this evening. There
is a chance for a ragged stratus deck Monday morning behind the
cold front at Spokane and Coeur D`Alene, especially if rains are
widespread enough to moisten the boundary layer. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 73 52 70 47 68 / 70 30 10 40 60 10
Coeur d`Alene 60 70 51 69 47 66 / 70 40 10 50 60 20
Pullman 58 72 46 69 41 68 / 60 20 10 50 50 10
Lewiston 64 81 57 75 52 73 / 60 10 10 40 50 10
Colville 61 73 49 72 46 70 / 80 70 20 60 50 40
Sandpoint 59 68 47 68 43 63 / 60 60 20 50 90 40
Kellogg 58 69 49 68 45 62 / 60 60 10 60 90 30
Moses Lake 62 77 52 74 48 74 / 70 10 10 20 10 10
Wenatchee 61 73 56 72 52 72 / 70 10 10 20 10 10
Omak 62 76 52 74 48 73 / 70 30 10 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch until 11 PM PDT this evening for East Slopes
Northern Cascades-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1156 AM PDT Sun Sep 15 2013
.SYNOPSIS...
The late summer warm spell will come to an end tonight after one
more day of well above average temperatures. A strong cold front
will sweep through the region, and bring a round of thunderstorms
and gusty winds tonight. Cooler and more seasonable weather can be
expected for next week along with a chance of showers.
&&
.DISCUSSION...
The majority of the morning model runs are in, and the timing of
the cold front is in line with our previous forecast. It still
looks like scattered thunderstorms will be possible late this
afternoon over the central and northern Washington Cascades.
Isolated thunderstorms can`t be ruled out for late this afternoon
over eastern Washington and north Idaho (south of Interstate-90).
However, the best concentration of thunderstorms will likely be
during the evening and overnight hours with the arrival of the
surface front and upper trough axis. I think that the 12z GFS
depiction of convection (which is several hours later) is better
than the 12z NAM. Surface observations through late morning show
dewpoints in the mid and upper 40s over the Idaho Panhandle and
the majority of eastern Washington which the GFS handles better
than the NAM. There will be a shift in the wind direction this
afternoon from east to south which may increase boundary layer
moisture/surface based instability late in the afternoon. However,
it looks like the NAM dewpoint progs moisten the low levels too
quickly and generate what appears to be surface based convection
too quickly over the Panhandle and the eastern third of
Washington. Perhaps the NAM is releasing model instability via
high based convection this afternoon. If this is the case, the
model is already producing too much convection over Idaho and
Oregon as of 18z (11AM PDT).
Why is the timing of thunderstorms so important? The earlier in
the day thunderstorms reach eastern Washington and northern Idaho,
the better chance they will have to produce strong winds and hail.
The GFS and HRRR suggest that peak thunderstorm activity will be
from mid evening through a few hours after midnight which may
limit the wind potential.
The flash flood threat for the Cascades looks to be lower than
some of our recent late summer events. Tonight`s upper trough is
more progressive which should limit the window for heavy rain over
the burn scars. However, the abundance of mid-level moisture and
vigorous forcing will raise the potential for brief heavy rain
rates. The hours of greatest concern for Wenatchee will be from
5 PM to 10 PM. /GKoch
&&
.AVIATION...
18Z TAFS: A vigorous cold front will produce showers and
thunderstorms from late this afternoon through Monday morning. The
12z GFS is preferred for the general timing of the convection over
eastern Washington and north Idaho. Gusty outflow winds and brief
heavy rains will accompany the strongest cells this evening. There
is a chance for a ragged stratus deck Monday morning behind the
cold front at Spokane and Coeur D`Alene, especially if rains are
widespread enough to moisten the boundary layer. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 89 60 74 52 70 47 / 20 60 50 10 30 50
Coeur d`Alene 88 57 72 51 69 47 / 20 60 60 20 40 60
Pullman 89 58 74 46 69 41 / 20 60 30 10 50 50
Lewiston 93 64 81 57 75 52 / 20 50 20 10 40 50
Colville 91 57 75 49 72 45 / 10 80 60 50 60 60
Sandpoint 86 54 70 47 68 43 / 10 70 60 40 50 90
Kellogg 87 55 70 49 67 45 / 20 70 60 30 60 90
Moses Lake 92 61 79 52 75 48 / 30 70 10 10 20 10
Wenatchee 88 61 76 56 72 52 / 30 70 20 10 20 10
Omak 90 60 78 52 74 48 / 10 70 50 20 30 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flash Flood Watch from 5 PM this afternoon to 11 PM PDT this
evening for East Slopes Northern Cascades-Wenatchee Area.
&&
$$