Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 05/13/12
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
959 AM PDT FRI MAY 11 2012
.SHORT TERM DISCUSSION...
HIGH PRESSURE RIDGING IS BUILDING IN TODAY BRINGING WARM
TEMPERATURES TO THE AREA. FORECAST ON TRACK TODAY FOR HIGHS TO BE
AROUND 4 TO 7 DEGREES WARMER THAN WE SAW YESTERDAY. THIS MEANS LOW
90S FOR THE VALLEY. BREEZY NORTH WINDS CONTINUE IN THE NORTHERN
SACRAMENTO VALLEY LOCALLY REACHING UP TO 27 MPH IN STRONGER GUSTS.
WILL UPDATE FORECAST TO INCREASE WINDS. HRRR MODEL SHOWS THESE
WINDS PEAKING LATER IN THE MORNING THEN DIMINISHING LATER IN THE
AFTERNOON.
MAIN FORECAST ISSUE IS UPPER LEVEL LOW APPROACHING THE NORTHERN
CALIFORNIA COAST ON SUNDAY. AFTERNOON CONVECTION IS
POSSIBLE...ESPECIALLY OVER THE NORTHERN SIERRA. A FURTHER
NORTHWARD SHIFT IN MODELS SUGGESTS THE MAIN THREAT OF
THUNDERSTORMS ON MONDAY WILL SHIFT NORTHWARD OVER THE SHASTA
COUNTY AREA...SO MAY NEED TO DECREASE POPS OVER THE SIERRA. EK
.EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY)
HIGH PRESSURE RIDGE BROADENS OVER THE WEST COAST THROUGH MIDWEEK
LEADING TO AN EXTENSION OF THE WARM AND DRY WEATHER. 850MB
TEMPERATURES WERE SLIGHTLY LOWER VERSUS YESTERDAYS GUIDANCE...
LEADING TO A FEW DEGREES OF COOLING AT THE SURFACE. VALLEY
TEMPERATURES STILL ON TRACK FOR NEAR NINETY DEGREES FOR NEXT WEEK.
THE MOST INTERESTING FEATURE IN THE EXTENDED PERIOD IS A 570DM
TIGHTLY PACKED CUTOFF LOW EMBEDDED WITHIN THE BROAD UPPER RIDGE.
MODEL GUIDANCE HAS STRUGGLED TO PIN DOWN TRAJECTORY AND PACING OF
THIS SYSTEM THE LAST FEW DAYS. 12Z RUNS OF GFS/ECMWF DEPICT THIS
LOW MOVING OVER THE AREA MID TO LATE MONDAY. THE EURO/GEM TRACK
THE LOW OVER CENTRAL/SOUTHERN CALIFORNIA... AND THE GFS SLANTS THE
PATH FURTHER NORTH ALONG THE CALIFORNIA/OREGON BORDER. THE
GFS/EURO SHOW THIS LOW SPREADS ELEVATED INSTABILITY AROUND THE
SOUTHERN CASCADES AND LASSEN PARK REGION WITH 350 J/KG OF MUCAPE
MONDAY. THE EURO BRINGS THE SAME ELEVATED INSTABILITY TO THE
SIERRA NEVADA MONDAY AFTERNOON. DONT EXPECT TO SEE ANYTHING IN THE
VALLEY WITH THIS SYSTEM... BUT WE MAY SEE A FEW ELEVATED
THUNDERSTORMS MONDAY AFTERNOON.
&&
.AVIATION...
VFR CONDITIONS OVER INTERIOR NORCAL FOR THE NEXT 24 HOURS.
BREEZY DOWNSLOPE WINDS OVER THE SIERRA WITH GUSTS UP TO 30 MPH
THROUGH 16Z. GENERALLY LIGHT WINDS WINDS ELSEWHERE THROUGH THE
DAY.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
945 PM MDT SAT MAY 12 2012
.UPDATE...
LATEST MODELS ARE BACKING OFF ON THE SOLN OF WIDESPREAD RAINFALL
SPREADING EASTWARD ACROSS THE SOUTHEAST PLAINS DURING THE LATE
EVENING/OVERNIGHT HOURS. NAM12 AND RUC13 DIMINISH AREA OF PCPN
QUICKLY AS IT MOVES OFF THE MTS INTO THE I-25 CORRIDOR OF EL
PASO/PUEBLO COUNTY THROUGH 06-09Z...WITH ALL QPF DONE BY 09Z. 00Z
HRRR RUN IS THE MOST OPTIMISTIC (WETTEST) HIGH RES MODEL FOR THE
I-25 CORRIDOR/ADJACENT PLAINS...WITH FAIRLY WIDESPREAD SHOWERS
MOVING EASTWARD ACROSS EL PASO/PUEBLO/NRN HUERFANO COUNTIES
THROUGH 06Z...HOWEVER IT TOO DOES DWINDLE PCPN QUICKLY AS IT
CONTINUES MOVING SOUTHEAST ACROSS CROWLEY...OTERO...BENT...AND
EASTERN LAS ANIMAS COUNTIES THROUGH 12Z...WITH FAR EASTERN
COUNTIES SEEING LITTLE OR NO RAINFALL OVERNIGHT. ALL THIS IS
LIKELY DUE TO THE SLOWER SOUTHWARD TREND IN THE UPPER LEVEL
SHORTWAVE TO THE NORTHWEST...WITH SYSTEM COMING THROUGH AT NIGHT
WHEN STABILIZATION HAS ALREADY OCCURRED. ISENTROPIC UPGLIDE ON THE
300-305K SFC ALSO LOOKS MUCH WEAKER AS A RESULT OF THIS SLOWER
TIMING...WHICH MEANS LESS FORCING TO CONTINUALLY GENERATE SHOWERS
OVERNIGHT. THUS...HAVE DECREASED POPS ACROSS THE SOUTHEAST
PLAINS. WILL MAINTAIN A SMALL WINDOW FOR LIKELY POPS ACROSS EL
PASO/PUEBLO COUNTIES (THROUGH 06Z FOR EL PASO COUNTY...AND THROUGH
09Z FOR PUEBLO COUNTY AND POINTS TO THE SE) AS THERE MAY BE ENOUGH
FORCING FOR AT LEAST SOME SHOWERS THROUGH THAT PERIOD. -KT
&&
.PREV DISCUSSION... /ISSUED 258 PM MDT SAT MAY 12 2012/
SHORT TERM...
(TONIGHT AND SUNDAY)
..ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TONIGHT...A LITTLE
DRIER ON SUNDAY BUT STILL ANOTHER ROUND OF SHOWERS AND STORMS...
WATER VAPOR PICTURES THIS AFTERNOON SHOW A RATHER VIGOROUS SHORTWAVE
DIGGING SOUTHEAST ACROSS NORTHEASTERN UTAH AND SOUTHWESTERN
WYOMING...HEADING INTO NORTHWEST COLORADO. THIS WAVE IS ALREADY
HELPING TO INITIATE CONVECTION IN A BIG WAY OVER ALL OF THE COLORADO
MOUNTAINS. ALTHOUGH MODELS DIFFER ON THE DETAILS OF WHERE AND HOW
MUCH RAIN WILL FALL...THEY ARE ALL IN AGREEMENT ON BRINGING FAIRLY
WIDESPREAD SHOWERS EAST OFF THE MOUNTAINS THIS AFTERNOON...ONTO THE
PLAINS THIS EVENING...AND CONTINUING ACROSS THE FAR EASTERN PLAINS
THROUGH THE OVERNIGHT HOURS. FOR THE MOST PART...THE MAIN WEATHER
TO EXPECT FROM THESE STORMS WILL BE RAIN. ALTHOUGH...AS THE CELLS
FIRST DEVELOP...IN THE PRE-STORM CAPE THAT IS AVAILABLE...THEY MAY
HAVE A BIT MORE UMP...AND DROP SOME HAIL FROM PEA UP TO PENNY SIZE.
ALREADY HAD ONE CASE OF THIS A LITTLE BEFORE 1 PM TODAY FROM A STORM
2 MILES EAST OF SOUTH FORK IN RIO GRANDE COUNTY. THE SPOTTER THERE
REPORTED DIME TO QUARTER SIZE HAIL FROM A CELL THAT DIDN`T LOOK LIKE
MUCH ON RADAR.
SNOW LEVELS TONIGHT WILL PROBABLY NOT BE QUITE AS LOW AS LAST
NIGHT. HIGHER DEWPOINT AIR HAS BEEN ADVECTING INTO THE REGION
TODAY...THUS LOWERING THE POTENTIAL FOR STRONG DIABATIC COOLING
DURING PRECIPITATION. YESTERDAY AT THIS TIME...DEWPOINTS AROUND THE
AREA WERE GENERALLY IN THE LOWER TO MIDDLE 30S. THIS AFTERNOON...
THEY HAVE WARMED MOSTLY TO THE UPPER 30S AND LOWER 40S...AND THEY
ARE FORECAST TO CONTINUE RISING A BIT MORE. SO...WET BULB ZERO
TEMPERATURES HAVE GONE UP AND...CONSEQUENTLY...SO HAVE THE SNOW
LEVELS. FOR TONIGHT...LOOKS LIKE ABOUT 9000 FEET FOR ACCUMULATING
SNOW POTENTIAL. HOWEVER...COULD SEE SOME WET SNOW DOWN TO ABOUT
8000 FEET DURING THE HEAVIER PRECIPITATION PERIODS...WITH LITTLE OR
NO SNOW ACCUMULATION EXPECTED.
FOR SUNDAY...UPPER LOW IS STILL MAKING ITS WAY SOUTH ACROSS THE
AREA. SO...WE WILL HAVE YET ANOTHER COOL AND UNSETTLED DAY BEFORE
THE PATTERN CHANGES. OVERALL...THE AIRMASS OVER SOUTHERN COLORADO
TOMORROW LOOKS A LITTLE DRIER...SO GENERALLY DO NOT THINK WE WILL
SEE AS HEAVY OF PRECIPITATION AMOUNTS AS THE PAST COUPLE OF DAYS.
HOWEVER...SHOULD STILL SEE FAIRLY GOOD COVERAGE OF LIGHT SHOWERS
ACROSS THE AREA. THE PEAK PERIOD FOR PRECIPITATION TOMORROW SHOULD
AGAIN ALIGN FAIRLY WELL WITH PEAK DIURNAL HEATING...SO THE BEST
CHANCE FOR SHOWERS AND THUNDERSTORMS SHOULD AGAIN BE DURING THE
AFTERNOON INTO THE EVENING HOURS. THIS TIME...THE PRECIPITATION
WILL PROBABLY FOCUS MORE ON LOCATIONS FROM THE I-25 CORRIDOR
WESTWARD...AND ALSO ALONG THE RATON MESA. THE PLAINS MAY NOT SEE
SO MUCH. LW
LONG TERM...
(SUNDAY NIGHT THROUGH NEXT SATURDAY)
FORECAST FOR NEXT WEEK LOOKS RELATIVELY QUIET AND UNEVENTFUL. THE
JET STREAM REMAINS WELL TO THE N...AND ASIDE FROM A FEW WEAK SHORT
WAVES TO CONTEND WITH...THE PATTERN LOOKS DRY AND WARM.
SHOWERS AND STORMS SHOULD WRAP UP FAIRLY QUICKLY SUN NIGHT AS THE
CURRENT UPPER DISTURBANCE PASSES INTO THE TX PANHANDLE. JUST SOME
LINGERING CONVECTION INTO MON...MAINLY ALONG OUR SRN BORDER WITH NM.
AN UPPR RIDGE BUILDS FROM MON INTO TUE...AND THIS WILL USHER IN
WARMER WEATHER WITH GENERALLY DRY CONDITIONS. HIGH TEMPS OVR THE
PLAINS LIKELY TO BE IN THE MID TO POSSIBLY UPPR 80S FOR THE LATTER
HALF OF THE WEEK...AS H7 TEMPS BUILD TO THE 10-15 DEG C RANGE.
ANOTHER WEAK DISTURBANCE MOVES QUICKLY THRU CO ON WED. DEWPOINTS E
OF A DIFFUSE DRY LINE SHOULD BE JUST HIGH ENOUGH FOR SOME STRONG
CONVECTION BY LATE AFTERNOON TO EARLY EVE...ESPECIALLY NR THE KS
BORDER. MID LEVEL FLOW STILL TOO WEAK TO PRODUCE ANY SIGNIFICANT
CHANCE OF SVR WX. MAIN THREAT WILL PROBABLY BE HEAVY RAIN AND
PERHAPS SMALL HAIL...BUT STILL SOME UNCERTAINTY ON THE STRENGTH OF
THIS SHORT WAVE.
AFTER THAT...MORE UPPR RIDGING BRINGS BACK DRY WX ALONG WITH
ABOVE AVERAGE TEMPERATURES FROM THU INTO NEXT WEEKEND. 44
AVIATION...
UPPER DISTURBANCE VISIBLE IN SATELLITE PICTURES WILL TRACK
SOUTHEAST ACROSS COLORADO TONIGHT. DISTURBANCE WILL RESULT IN
CONTINUED WIDESPREAD IFR/MVFR CIGS ACROSS THE PLAINS. MOUNTAINS
AND VALLEYS ARE GENERALLY ABOVE THE LOW STRATUS DECK ACROSS THE
PLAINS...SO IFR/MVFR CIGS WILL BE MORE TRANSIENT...TIED TO CONVECTIVE
SHOWERS MOVING THROUGH. UPPER DISTURBANCE WILL BRING ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS ONTO THE
PLAIN LATE THIS AFTERNOON. THESE SHOWERS AND STORMS WILL TRANSITION
EASTWARD ACROSS THE PLAINS THIS EVENING...PROGRESSING ACROSS THE FAR
EASTERN PLAINS THROUGH THE OVERNIGHT HOURS. ACCUMULATING SNOW
POTENTIAL DOWN TO ABOUT 9000 FEET. HOWEVER...SOME WET SNOW WITH
LITTLE SNOW ACCUMULATION POSSIBLE DOWN TO ABOUT 8000 FEET. UPPER LOW
WILL STILL BE TRAVERSING SOUTH ACROSS THE REGION ON SUNDAY. NO
REAL IMPROVEMENT EXPECTED IN WEATHER CONDITIONS UNTIL LATE
SUNDAY NIGHT AND MONDAY...WHEN EVERYTHING SHIFTS SOUTH INTO NEW
MEXICO AND HIGH PRESSURE REBUILDS OVER COLORADO. LW
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MDT SUNDAY FOR COZ060-073-075-
082.
&&
$$
27/31
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1011 PM EDT SAT MAY 12 2012
.EVENING UPDATE...
A LOW PRESSURE SYSTEM OVER THE LOWER MISSISSIPPI VALLEY REGION WILL
GRADUALLY LIFT TO THE NORTHEAST TONIGHT... SPREADING AMPLE SHOWERS
AND A FEW THUNDERSTORMS ACROSS THE DEEP SOUTH OVERNIGHT. WEAK
INSTABILITIES...ABUNDANT LOW LEVEL MOISTURE AND SOME UPPER LEVEL
FORCING WILL WARRANT HOLDING ONTO A SLIGHT CHANCE OF THUNDERSTORMS
ACROSS PARTS OF NW AND WEST CENTRAL GA TONIGHT...MAINLY WEST OF AN
ELLIJAY TO MARIETTA TO HAMILTON LINE. STILL EXPECT NUMEROUS SHOWERS
TO SPREAD IN OVER THE FORECAST AREA TONIGHT AND CONTINUE ON SUNDAY.
HAVE TWEAKED THE FORECAST TO ADD SLIGHT CHANCE OF THUNDERSTORMS FOR
THE FAR WESTERN REACHES... BUT THE REST OF THE FORECAST LOOKS ON
TRACK AT THIS TIME. /39
.PREV DISCUSSION... /ISSUED 359 PM EDT SAT MAY 12 2012/
SHORT TERM /TONIGHT THROUGH MONDAY/...
MAIN FORECAST CONCERN WILL BE QPF AND POPS ASSOCIATED WITH
DEVELOPING LOW PRESSURE SYSTEM APPROACHING THE FORECAST AREA FROM
THE WEST. MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THIS FEATURE
HOWEVER THE GFS SEEMS TO HAVE A SLIGHTLY BETTER HANDLE ON IT AND
THE ASSOCIATED PRECIPITATION...THEREFORE MADE MINOR TWEAKED TO MAV
INITIALIZATION. HRRR IS SUGGESTING SOME SCATTERED SHOWER
DEVELOPMENT AHEAD OF THE MAIN SWATH AFTER 21Z THIS EVENING...
WHILE THE MORE WIDESPREAD RAIN SHOULD AFFECT THE WESTERN PORTIONS
AFTER ABOUT 03Z. HAVE THEREFORE KEPT CHANCE POPS THIS AFTERNOON
AND INCREASED TO LIKELY AND CATEGORICAL POPS ACROSS THE
NORTHWESTERN HALF OF THE AREA OVERNIGHT. SOME BREAKS IN THE CLOUD
DECK THIS AFTERNOON HAS ALLOWED CAPE VALUES TO INCREASE SOMEWHAT
SO THERE IS STILL A SLIGHT CHANCE FOR THUNDERSTORMS.
SUNDAY LOOKS TO BE THE WETTEST DAY IN THE SHORT TERM WITH THE
HEAVIEST RAINFALL LIKELY OCCURRING IN THE NORTHERN PORTIONS OF THE
AREA DURING THE MORNING AND SUNDAY OVERNIGHT. LATEST 12Z GFS AND NAM
TIME HEIGHTS ALSO SHOW DEEPEST HIGH RH LAYER INFLUENCING THE AREA ON
SUNDAY WITH LESS MOISTURE ON MONDAY THAN PREVIOUSLY THOUGHT. HAVE
THEREFORE MAINTAINED CATEGORICAL POPS IN THE NORTH... LIKELY POPS
CENTRAL... AND HIGH END CHANCE POPS SOUTH THROUGH SUNDAY. MODELS DO
INDICATED A BIT HIGHER CAPE VALUES AFTER 18Z SUNDAY SO HAVE INCLUDED
CHANCE OF THUNDERSTORMS. THE UPPER LEVEL SHORTWAVE TROUGH AXIS
SHOULD SWING THROUGH THE AREA BY AROUND 18Z MONDAY AND THE WEAK COLD
FRONT ASSOCIATED WITH THE PHASED SURFACE LOW SHOULD PASS AROUND 00Z
TUESDAY...THUS ALLOWING FOR CHANCE POPS TO CONTINUE THROUGH MUCH OF
THE DAY. LESS QPF IS EXPECTED DURING THIS TIME HOWEVER.
FOR TOTAL QPF...HPC GUIDANCE IS OVERALL LEANING MORE TOWARD GFS
AMOUNTS GIVING 48 HOUR RAINFALL TOTALS OF NEAR 2.5 INCHES IN THE
NORTH TO HALF AN INCH IN THE SOUTHEAST BY 00Z TUESDAY. THE HEAVIEST
OF WHICH SHOULD OCCUR SUNDAY MORNING AND SUNDAY OVERNIGHT.
FOR TEMPS...MAV GUIDANCE SEEMS TO HAVE BEEN DOING WELL WITH PROGGED
HIGHS AND LOWS SO MADE ONLY MINOR TWEAKS. MONDAY LOOKS TO BE A BIT
WARMER THAN TUESDAY WITH HIGHS IN THE MID TO UPPER 70S NORTH AND LOW
TO MID 80S SOUTH.
03
LONG TERM /TUESDAY THROUGH SATURDAY/...
MODELS CONTINUE TO HOLD A BROAD TROUGH ACROSS THE SOUTHEAST THROUGH
THE PERIOD. LOW PRESSURE DEVELOPING IN THE CENTRAL GULF SHOULD BE
INTO THE WESTERN CAROLINAS AT THE BEGINNING OF THE PERIOD...WITH
MOST OF THE RAINFALL EAST OF THE CWA. HAVE HELD ON TO LOW POPS
ACROSS THE EASTERN ZONES INTO WEDNESDAY NIGHT. SOME QUESTION AS TO
HOW MUCH MOISTURE LINGERS BEHIND THIS SYSTEM AS MODELS HOLD THE
BROAD UPPER TROUGH ACROSS THE SOUTHEAST AND REMNANTS OF THE
SURFACE FRONT DRIFT ACROSS CENTRAL OR SOUTH GEORGIA. HAVE NOT
ADDED ANY POPS TO THE LAST FEW DAYS DUE TO LOW CONFIDENCE IN THE
MODEL SOLUTION.
41
HYDROLOGY...
/ISSUED 330 PM EDT SAT MAY 12 2012/
HPC 1-3 DAY QPF TOTAL ENDING 12Z TUESDAY SHOWS 2.5 TO 3.00 ACROSS
EXTREME NORTH GEORGIA AND LESSER AMOUNTS ELSEWHERE. 6 HOUR FFG
VALUES ARE AROUND 4.5 INCHES OVER THE NORTH. WITH EXPECTED
RAINFALL SPREAD OVER A COUPLE OF DAYS...THINK WE SHOULD BE ABLE
TO HANDLE THESE FORECAST AMOUNTS...BUT WILL HAVE TO WATCH FOR
LOCALIZED PROBLEMS ON THE CREEKS AND RIVERS ACROSS THE NORTH.
41
&&
.AVIATION...
/ISSUED AT 828 PM EDT SAT MAY 12 2012/
00Z UPDATE...
INCREASING CLOUDS AND PRECIPITATION MOVING INTO THE AREA THIS
EVENING. SHOWERS SHOULD START MOVING INTO ATL WITH IN THE HOUR AND
CONTINUE TO BE OFF AND ON OVER THE NEXT 24-48 HOURS. CEILINGS ARE
VFR BUT THEY WILL GET DOWN INTO THE IFR RANGE BETWEEN 06Z-18Z
WINDS WILL STAY OUT OF THE SE THEN TURN SW AFTER 00Z MON. WIND
SPEEDS WILL STAY IN THE 6-12KT RANGE WITH SOME GUST DURING THE
DAY SUNDAY.
//ATL CONFIDENCE...00Z UPDATE...
CONFIDENCE MEDIUM THROUGH THE TAF PERIOD.
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 59 73 62 79 / 50 70 60 50
ATLANTA 62 73 63 77 / 70 80 50 40
BLAIRSVILLE 57 65 59 74 / 60 80 80 50
CARTERSVILLE 63 71 63 77 / 80 80 70 40
COLUMBUS 65 79 65 81 / 70 60 50 40
GAINESVILLE 59 70 62 77 / 60 80 80 50
MACON 61 79 63 82 / 50 50 50 50
ROME 63 75 62 80 / 80 80 60 40
PEACHTREE CITY 60 75 60 78 / 70 80 50 40
VIDALIA 66 81 67 84 / 30 50 50 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....DARBE
AVIATION...01
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
828 PM EDT SAT MAY 12 2012
.PREV DISCUSSION... /ISSUED 359 PM EDT SAT MAY 12 2012/
SHORT TERM /TONIGHT THROUGH MONDAY/...
MAIN FORECAST CONCERN WILL BE QPF AND POPS ASSOCIATED WITH
DEVELOPING LOW PRESSURE SYSTEM APPROACHING THE FORECAST AREA FROM
THE WEST. MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THIS FEATURE
HOWEVER THE GFS SEEMS TO HAVE A SLIGHTLY BETTER HANDLE ON IT AND
THE ASSOCIATED PRECIPITATION...THEREFORE MADE MINOR TWEAKES TO MAV
INITIALIZATION. HRRR IS SUGGESTING SOME SCATTERED SHOWER
DEVELOPMENT AHEAD OF THE MAIN SWATH AFTER 21Z THIS EVENING...
WHILE THE MORE WIDESPREAD RAIN SHOULD AFFECT THE WESTERN PORTIONS
AFTER ABOUT 03Z. HAVE THEREFORE KEPT CHANCE POPS THIS AFTERNOON
AND INCREASED TO LIKELY AND CATEGORICAL POPS ACROSS THE
NORTHWESTERN HALF OF THE AREA OVERNIGHT. SOME BREAKS IN THE CLOUD
DECK THIS AFTERNOON HAS ALLOWED CAPE VALUES TO INCREASE SOMEWHAT
SO THERE IS STILL A SLIGHT CHANCE FOR THUNDERSTORMS.
SUNDAY LOOKS TO BE THE WETTEST DAY IN THE SHORT TERM WITH THE
HEAVIEST RAINFALL LIKELY OCCURRING IN THE NORTHERN PORTIONS OF THE
AREA DURING THE MORNING AND SUNDAY OVERNIGHT. LATEST 12Z GFS AND NAM
TIME HEIGHTS ALSO SHOW DEEPEST HIGH RH LAYER INFLUENCING THE AREA ON
SUNDAY WITH LESS MOISTURE ON MONDAY THAN PREVIOUSLY THOUGHT. HAVE
THEREFORE MAINTAINED CATEGORICAL POPS IN THE NORTH... LIKELY POPS
CENTRAL... AND HIGH END CHANCE POPS SOUTH THROUGH SUNDAY. MODELS DO
INDICATED A BIT HIGHER CAPE VALUES AFTER 18Z SUNDAY SO HAVE INCLUDED
CHANCE OF THUNDERSTORMS. THE UPPER LEVEL SHORTWAVE TROUGH AXIS
SHOULD SWING THROUGH THE AREA BY AROUND 18Z MONDAY AND THE WEAK COLD
FRONT ASSOCIATED WITH THE PHASED SURFACE LOW SHOULD PASS AROUND 00Z
TUESDAY...THUS ALLOWING FOR CHANCE POPS TO CONTINUE THROUGH MUCH OF
THE DAY. LESS QPF IS EXPECTED DURING THIS TIME HOWEVER.
FOR TOTAL QPF...HPC GUIDANCE IS OVERALL LEANING MORE TOWARD GFS
AMOUNTS GIVING 48 HOUR RAINFALL TOTALS OF NEAR 2.5 INCHES IN THE NORTH
TO HALF AN INCH IN THE SOUTHEAST BY 00Z TUESDAY. THE HEAVIEST OF
WHICH SHOULD OCCUR SUNDAY MORNING AND SUNDAY OVERNIGHT.
FOR TEMPS...MAV GUIDANCE SEEMS TO HAVE BEEN DOING WELL WITH PROGGED
HIGHS AND LOWS SO MADE ONLY MINOR TWEAKS. MONDAY LOOKS TO BE A BIT
WARMER THAN TUESDAY WITH HIGHS IN THE MID TO UPPER 70S NORTH AND LOW
TO MID 80S SOUTH.
03
LONG TERM /TUESDAY THROUGH SATURDAY/...
MODELS CONTINUE TO HOLD A BROAD TROUGH ACROSS THE SOUTHEAST THROUGH
THE PERIOD. LOW PRESSURE DEVELOPING IN THE CENTRAL GULF SHOULD BE
INTO THE WESTERN CAROLINAS AT THE BEGINNING OF THE PERIOD...WITH
MOST OF THE RAINFALL EAST OF THE CWA. HAVE HELD ON TO LOW POPS
ACROSS THE EASTERN ZONES INTO WEDNESDAY NIGHT. SOME QUESTION AS TO
HOW MUCH MOISTURE LINGERS BEHIND THIS SYSTEM AS MODELS HOLD THE
BROAD UPPER TROUGH ACROSS THE SOUTHEAST AND REMNANTS OF THE
SURFACE FRONT DRIFT ACROSS CENTRAL OR SOUTH GEORGIA. HAVE NOT
ADDED ANY POPS TO THE LAST FEW DAYS DUE TO LOW CONFIDENCE IN THE
MODEL SOLUTION.
41
HYDROLOGY...
/ISSUED 330 PM EDT SAT MAY 12 2012/
HPC 1-3 DAY QPF TOTAL ENDING 12Z TUESDAY SHOWS 2.5 TO 3.00 ACROSS
EXTREME NORTH GEORGIA AND LESSER AMOUNTS ELSEWHERE. 6 HOUR FFG
VALUES ARE AROUND 4.5 INCHES OVER THE NORTH. WITH EXPECTED
RAINFALL SPREAD OVER A COUPLE OF DAYS...THINK WE SHOULD BE ABLE
TO HANDLE THESE FORECAST AMOUNTS...BUT WILL HAVE TO WATCH FOR
LOCALIZED PROBLEMS ON THE CREEKS AND RIVERS ACROSS THE NORTH.
41
&&
.AVIATION...
00Z UPDATE...
INCREASING CLOUDS AND PRECIPITATION MOVING INTO THE AREA THIS
EVENING. SHOWERS SHOULD START MOVING INTO ATL WITH IN THE HOUR AND
CONTINUE TO BE OFF AND ON OVER THE NEXT 24-48 HOURS. CEILINGS ARE
VFR BUT THEY WILL GET DOWN INTO THE IFR RANGE BETWEEN 06Z-18Z
WINDS WILL STAY OUT OF THE SE THEN TURN SW AFTER 00Z MON. WIND
SPEEDS WILL STAY IN THE 6-12KT RANGE WITH SOME GUST DURING THE
DAY SUNDAY.
//ATL CONFIDENCE...00Z UPDATE...
CONFIDENCE MEDIUM THROUGH THE TAF PERIOD.
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 59 73 62 79 / 50 70 60 50
ATLANTA 62 73 63 77 / 70 80 50 40
BLAIRSVILLE 57 65 59 74 / 60 80 80 50
CARTERSVILLE 63 71 63 77 / 80 80 70 40
COLUMBUS 65 79 65 81 / 70 60 50 40
GAINESVILLE 59 70 62 77 / 60 80 80 50
MACON 61 79 63 82 / 50 50 50 50
ROME 63 75 62 80 / 80 80 60 40
PEACHTREE CITY 60 75 60 78 / 70 80 50 40
VIDALIA 66 81 67 84 / 30 50 50 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....DARBE
AVIATION...01
AREA FORECAST DISCUSSION
NWS DES MOINES IA
316 PM CDT FRI MAY 11 2012
.SHORT TERM /TONIGHT/...
THE COLD FRONT WAS ALONG A NEWTON TO LAMONI LINE AT 20Z THIS
AFTERNOON. VISIBLE SATELLITE IMAGERY WAS SHOWING A FEW CU DEVELOPING
NEAR THE BOUNDARY. SURFACE DEW POINTS ALONG AND AHEAD OF THE FRONT
WERE IN THE MID TO UPPER 50S. THE 19Z SPC THERMODYNAMICS FIELDS
SUGGEST MODEST INSTABILITY WITH VERY WEEK MOISTURE CONVERGENCE ALONG
THE FRONT. THROUGH THE EARLY EVENING...EXPECT THE FRONT TO SLOWLY
MOVE SOUTHEAST REACHING DAVIS COUNTY BY 7 PM. 12Z GFS/NAM AND THE
LATEST HRRR DEVELOP SHOWERS OR THUNDERSTORMS NEAR THE FRONT THIS
EVENING. THERE WILL BE ENOUGH INSTABILITY AND LIFT TO KEEP A SMALL
CONDITIONAL CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST.
WEAK MID LEVEL FORCING AHEAD OF POSITIVELY TILTED 700 MB TROUGH AND
MID-LEVEL MOISTURE MAY BE ADEQUATE TO PRODUCE SCATTERED SHOWERS OVER
SOUTH CENTRAL IOWA TONIGHT ALONG WITH CLOUDINESS. PREVIOUS
TEMPERATURE FORECAST LOOKED GOOD REQUIRING ONLY MINOR ADJUSTMENTS.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
RATHER QUIET PERIOD TO CONTINUE INTO THE WEEKEND AND NEXT WEEK. A
FEW ITEMS TO MENTION INCLUDING COLD FRONTAL BOUNDARY HANGING UP OVER
CENTRAL TO NORTHERN MO ON SATURDAY MAY HAVE ENOUGH ISENTROPIC LIFT
TO KEEP A FEW SHOWERS OVER FAR SOUTHERN IOWA SATURDAY AND SATURDAY
EVENING. CLOUDS WILL ALSO LINGER OVER THE SOUTH ON SATURDAY BUT
SHOULD EXIT THE REGION BY SATURDAY EVENING LEAVING SUNDAY MAINLY
SUNNY AND QUIET. MODEST FLOW REMAINS ACROSS THE NORTHERN TIER STATES
WITH A FEW WAVES TRAVELING ALONG THE US CAN BORDER. A WEAK COOL
FRONT HAS BEEN ADVERTISED TO CROSS THE REGION BY TUESDAY EVENING OR
WEDNESDAY MORNING. THIS WILL ALLOW FOR SLIGHTLY COOLER AIR TO DROP
INTO THE REGION FOR A DAY PRIOR TO THE FRONT LIFTING BACK NORTH BY
WEDNESDAY NIGHT AND THURSDAY. CLIMATOLOGY FAVORS SOME THUNDER
ACTIVITY AS THE FRONT LIFTS NORTH...BUT MODELS REMAIN RATHER DRY AS
FLOW OVER THE SOUTH HAS BEEN SHUT DOWN WITH WEAK LOW PRESSURE AND
NORTHWEST FLOW HUGGING THE GULF COAST. THUS...AM RELUCTANT TO GET
TOO EXCITED ABOUT POP IN THE REMAINDER OF THE EXTENDED PERIOD UNTIL
A STRONGER WAVE DROPS INTO THE WEST. IT APPEARS THAT THE NEXT
OPPORTUNITY FOR THAT WILL COME 24 TO 48 HOURS FOLLOWING THE CURRENT
EXTENDED FORECAST. FORECAST HIGHS WILL WARM NICELY BY THE END OF THE
EXTENDED PERIOD. WITH SW FLOW IN PLACE AND GOOD MIXING COMBINED WITH
H850 TEMPS OF 17-19C...WILL LIKELY SEE HIGHS IN THE MID TO UPPER 80S
IF THE TREND HOLDS. COORD WITH SURROUNDING OFFICES WITH LOWER 80S IN
MIND AND WILL WAIT FOR A FEW MORE CONFIRMATION RUNS PRIOR TO RAISING
TEMPS HIGHER...BUT BOTH H500 PATTERN WITH RIDGE BUILDING OVER THE
LOWER MS RIVER VALLEY AND INCREASING H850 TEMPS SUPPORT VERY WARM
AND INCREASINGLY HUMID AIRMASS NORTH INTO THE REGION. EURO THICKNESS
BY 00Z SAT 5/19 BACK TO 570-573DM WHICH IS RATHER SUMMER LIKE.
&&
.AVIATION...11/18Z
COLD FRONT EXTENDED FROM MASON CITY TO AUDUBON AT 17Z. EXPECT THE
FRONT TO MOVE THROUGH CENTRAL IA THIS AFTERNOON REACHING OTTUMWA
AROUND 22Z. MODEL SOUNDINGS SUGGEST THAT A SCATTERED CU FIELD
SHOULD DEVELOP THIS AFTERNOON NEAR THE COLD FRONT. MODEST
INSTABILITY AND CONVERGENCE ALONG THE BOUNDARY MAY PRODUCE WIDELY
SCATTERED THUNDERSTORMS NEAR THE BOUNDARY OVER SOUTH CENTRAL IOWA
LATE THIS AFTERNOON AND EVENING. THERE APPEARS TO BE ENOUGH MID
LEVEL FORCING AND MOISTURE NORTH OF THE FRONT TONIGHT TO PRODUCE A
VFR COULD DECK AND A CHANCE OF SHOWERS OVER THE SOUTHERN IOWA.
SHOULD STAY VFR THROUGH THE FORECAST PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM/AVIATION...JOHNSON
LONG TERM...REV
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
312 PM CDT FRI MAY 11 2012
.SYNOPSIS...
MOISTURE STARVED SURFACE COLD FRONT CONTINUES CRAWL SLOWLY ACROSS IA
THIS AFTERNOON...REACHING FROM WEST CENTRAL WI...TROUGH MASON CITY
TO WEST OF DES MOINES...INTO FAR NW MO AT 19Z. VISIBLE SATELLITE
SHOWED MOSTLY CLEAR SKIES OVER THE FORECAST AREA WITH SIGNIFICANT
CLOUD COVER NEAR THE BOUNDARY LIMITED TO MN AND WI...WHILE POST
FRONTAL CLOUDS ASSOCIATED WITH HIGHER MOISTURE AND MID AND UPPER
LEVEL FORCING WERE WELL TO THE NW FROM NW NEB THROUGH SE SD INTO MN.
AREA RADAR MOSAIC INDICATED A BAND OF SHOWERS WELL BEHIND THE FRONT
FROM W CENTRAL MN INTO N CENTRAL NEB. ISOLATED HIGH BASED SHOWERS
WERE BEGINNING TO POP UP IN W CENTRAL AND NW IA OVER THE PAST HOUR.
TEMPERATURES WERE INTO THE UPPER 70S TO LOWER 80S OVER THE FORECAST
AREA...WHILE UPPER 60S TO LOWER 70S WERE FOUND WEST OF THE BOUNDARY
ACROSS WESTERN IA AND SW MN.
&&
.SHORT TERM...TONIGHT AND SATURDAY...
PRIMARY CHALLENGE IS RAIN CHANCES AS THE COLD FRONT PUSHES THROUGH
THE AREA TONIGHT INTO SATURDAY. WITH GULF MOISTURE RATHER MEAGER AND
LIMITED BY A LOW MOVING ACROSS TX TODAY...SURFACE DEWPOINTS HAVE
ONLY REACHED A NARROW AXIS OF MID 50S AHEAD OF THE FRONT...AND 850
MB ANALYSIS FROM THIS MORNING WOULD SUGGEST BULK OF GULF MOISTURE TO
REMAIN CUTOFF IN THE SOUTHERN PLAINS. CLOSE INSPECTION OF THE LATEST
VISIBLE SATELLITE SHOWS THE FIRST CU OF THE DAY STARTING TO POP
ALONG THE BOUNDARY NEAR DSM...AND WILL WATCH THIS DEVELOPMENT ALONG
AND AHEAD OF THE FRONT FOR POSSIBLE SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AS MUCAPES RISE TO VALUES WELL BELOW 1000 J/KG.
OTHERWISE...IT LOOKS LIKE THE BETTER FORCING FOR SHOWERS TONIGHT
WILL MORE CLOSELY TIED TO THE WEAK FORCING AND MOISTURE AROUND 700
MB ASSOCIATED WITH THE CURRENT AXIS OF POST FRONTAL SHOWERS. THIS
FEATURE FOLLOWS THE FRONT INTO THE FORECAST AREA LATER THIS EVENING
AND OVERNIGHT AND WILL KEEP CHANCE POPS IN PLACE. WILL KEEP AN
MENTION OF ISOLATED THUNDERSTORMS FOR THE EVENING FOR THE POSSIBLE
DEVELOPMENT OF CONVECTION ALONG THE ADVANCING BOUNDARY...WHICH IS
STILL SUGGESTED AS POSSIBILITY BY THE HRRR MODEL. OTHERWISE...
INCREASING CLOUD COVER WILL OFFSET THE LOW LEVEL COLD AIR ADVECTION
BEHIND THE WEAKENING COLD FRONT AND LIMIT LOWS TO AROUND 50 NORTH TO
THE MID 50S SOUTH.
SATURDAY...THE FRONT CONTINUES TO WEAKEN AND SLOW AS IT DROPS TOWARD
THE UPPER LEVEL SYSTEM MOVING THROUGH THE MID MS VALLEY. WEAK MID
LEVEL FORCING AND MOISTURE IS SHOWN POOLING NORTH OF THE BOUNDARY
THROUGH AT LEAST THE MORNING HOURS TO JUSTIFY CHANCE POPS FOR LIGHT
RAIN SHOWERS. THIS THEN SHIFTS TO THE FAR SOUTH IN THE AFTERNOON AS
SURFACE HIGH PRESSURE BUILDS OVER THE NORTHERN PLAINS INTO THE UPPER
MS VALLEY...INCREASING THE LOW LEVEL FLOW OF DRY AIR INTO THE AREA.
LINGERING MID AND HIGH LEVEL MOISTURE AND WEAK FORCING EMBEDDED IN
THE MID LEVEL CYCLONIC FLOW TO THE NORTH WILL LIKELY KEEP SKIES
MOSTLY CLOUDY AND WILL LIMIT HIGHS TO THE 60S OVER MOST OF THE
AREA. SHEETS
.LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY...
MAIN FOCUS THIS FORECAST TIME RANGE IS ON PRECIPITATION CHANCES
SATURDAY NIGHT AND AGAIN WEDNESDAY THROUGH FRIDAY.
SATURDAY NIGHT AND SUNDAY THE COLD FRONT CONTINUES TO SAG SOUTH. THE
850MB BOUNDARY REMAINS IN THE AREA SATURDAY NIGHT AND A WEAK VORT
MAX WILL DROP SOUTH ACROSS THE AREA. THIS MAY PRODUCE SOME ELEVATED
SHOWERS SATURDAY NIGHT...MAINLY IN THE EVENING. MOISTURE IS A
LIMITING FACTOR SO HAVE KEPT PRECIPITATION CHANCES IN THE SLIGHT
CHANCE CATEGORY. TEMPERATURES TO BE MILD BOTH PERIODS WITH CLOUDS
TEMPERING THE COOLER AND DRIER AIR COMING IN FROM THE NORTH. MINS
SATURDAY NIGHT IN THE 40S AND LOW 50S. HIGHS SUNDAY TO BE IN THE
LOW 70S.
MONDAY AND TUESDAY A WEAK SURFACE RIDGE TO BUILD SOUTH ACROSS THE
AREA WITH WEAK WESTERLY RETURN FLOW SETTING UP FOR TUESDAY. THIS
WILL ALLOW TEMPERATURES TO RISE SO THAT ON TUESDAY WE WILL HAVE
HIGHS IN THE UPPER 70S AGAIN...POSSIBLY EVEN SOME MORE LOW 80S.
FORECAST HIGHS MAY NEED TO BE RAISED IF IT STILL APPEARS WE WILL BE
WORKING WITH VERY DRY AIR AND DEEP MIXING.
WEDNESDAY THROUGH FRIDAY THE SURFACE RIDGE SLIPS OFF TO THE
SOUTHEAST AND SOUTHWEST RETURN FLOW SETS IN IN EARNEST WITH A LONG
FETCH FROM TEXAS...AND BY FRIDAY IT APPEARS THAT THERE WILL BE
STREAM OF GULF MOISTURE HEADING OUR DIRECTION. A FAIRLY STRONG
UPPER LEVEL SYSTEM OVER CANADA WILL PUSH A COLD FRONT TOWARDS THE
AREA WEDNESDAY. THIS FRONT MAY DROP INTO THE AREA WEDNESDAY...
THOUGH THERE IS SOME MODEL DISAGREEMENT HERE...WITH SOME KEEPING IT
NORTH OF THE AREA. FOR NOW HAVE KEPT THE FORECAST DRY AS THERE IS
LITTLE MOISTURE AVAILABLE FOR THIS BOUNDARY TO WORK WITH. A SURFACE
LOW IS GENERATED OVER WESTERN KANSAS...AND BY THURSDAY AND FRIDAY
THE FRONT BECOMES A WARM FRONT AND PUSHES BACK NORTH...AND WILL BE
GENERALLY DRAPED FROM SOUTH DAKOTA ACROSS SOUTHERN MINNESOTA AND
INTO WISCONSIN. UNLESS THIS CHANGES THIS IS LIKELY TO BE THE STORM
TRACK NEXT WEEK...AND WE WILL BE SITTING IN A VERY WARM AND
INCREASINGLY HUMID AIRMASS BOTH DAYS...WITH HIGHS INTO THE LOW 80S.
HAVE SOME VERY LOW END CHANCE POPS IN THE FORECAST...BUT UNLESS THE
FRONT SHIFTS CLOSER TO THE AREA AM ANTICIPATING WE WILL BE DRY.
LE
&&
.AVIATION...
A COLD FRONT REACHING FROM WESTERN WI THROUGH CENTRAL IA EARLY THIS
AFTERNOON WILL DRIVE SOUTHEAST THROUGH EASTERN IA AND NW IL
TONIGHT. AHEAD OF THE FRONT...GUSTY SOUTH WINDS WILL CONTINUE
THROUGH THE AFTERNOON...THEN BECOME LIGHT WEST TO NORTHWEST
FOLLOWING THE FRONTAL PASSAGE THIS EVENING ACROSS THE TERMINALS.
THERE WILL BE POTENTIAL FOR SHOWERS AND PERHAPS AND ISOLATED EVENING
THUNDERSTORM FOLLOWING THE FRONT...BUT WITH LIMITED COVERAGE
EXPECTED...WILL HAVE ONLY PROB30 GROUPS AND VC WORDING FOR SHOWERS
LATE TONIGHT INTO SATURDAY MORNING AND NOT INCLUDE ANY MENTION OF
THUNDER. WINDS WILL VEER TO THE NORTHWEST AND THEN NORTH TO
NORTHEAST SATURDAY MORNING. FLIGHT RULES ARE EXPECTED TO REMAIN VFR
THROUGHOUT...WITH A BRIEF PERIOD OF MVFR CIGS POSSIBLE WITH SHOWERS
LATE TONIGHT AND SATURDAY MORNING.
SHEETS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1251 PM CDT FRI MAY 11 2012
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
UPPER LOW MEANDERING NORTHEAST OVER THE SOUTHERN PLAINS SHOULD
ROTATE AREAS OF RAIN NORTHWARD INTO SOUTHERN/SOUTHEAST KS FROM
LATE THIS AFTERNOON THROUGH TONIGHT AND INTO SATURDAY MORNING.
TERMINALS AFFECTED WILL BE KCNU AND POSSIBLY KICT.
ADDITIONALLY...CANNOT RULE OUT A FEW ISOLATED TO WIDELY SCATTERED
SHOWERS/THUNDERSTORMS FOR KRSL-KSLN-KHUT LATE THIS AFTERNOON
THROUGH EVENING ALONG A COLD FRONT APPROACHING FROM THE NORTHWEST.
HOWEVER...NOT EXPECTED WIDESPREAD ACTIVITY BY ANY MEANS DUE TO
WEAK INSTABILITY AND FORCING. THINKING CIGS AS LOW AS 3000-4000 FT
AGL COULD DEVELOP ACROSS THE AREA TONIGHT...EARLIEST FOR KSLN-
KRSL...AS COOLER AIR FILTERS SOUTH. STOUT NORTH/NORTHEAST WINDS
ANTICIPATED BEHIND THE COLD FRONT THROUGH SATURDAY.
ADK
&&
.PREV DISCUSSION... /ISSUED 1101 AM CDT FRI MAY 11 2012/
UPDATE...
UPDATED THE FORECAST TO INCREASE POPS OVER FAR SOUTH-CENTRAL AND
SOUTHEAST KANSAS THIS AFTERNOON...AS NORTHERN-MOST LOBE OF ENERGY
ASSOCIATED WITH SOUTHERN PLAINS UPPER LOW ROTATES NORTHWARD.
THINKING COVERAGE WILL BE DECENT AFTER 4 PM...ESPECIALLY SOUTH OF
HIGHWAYS 54/400. THE LATEST HRRR MODEL SEEMED TO HAVE A GOOD FEEL
FOR CURRENT AND EXPECTED PRECIPITATION COVERAGE. ADDITIONALLY...AN
ISOLATED SHOWER/THUNDERSTORM OR TWO WILL BE POSSIBLE AFTER 4-5 PM
OVER CENTRAL KANSAS ALONG A COLD FRONT APPROACHING FROM THE
NORTHWEST...ALSO SUPPORTED BY THE HRRR. IN ALL INSTANCES...NOT
ANTICIPATING SEVERE WEATHER DUE TO MEAGER INSTABILITY AND FORCING.
ADK
PREV DISCUSSION... /ISSUED 650 AM CDT FRI MAY 11 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
PRIMARY FOCUS THIS MORNING IS ON SE PROGRESS OF COLD FRONT THAT HAS
ENTERED NW KS ~09Z. FRONT APPEARS TO BE DECELERATING & AS SUCH WOULD
EXPECT ONLY KRSL TO EXPERIENCE COLD FRONTAL PASSAGE THIS MORNING WITH
WINDS BECOMING NE 13-17KTS THIS AFTERNOON. A FEW -SHRA POSSIBLE OVER
CNTRL KS ALONG THE FRONT BUT LIMITED COVERAGE DICTATES LEAVING OUT OF
TAF UNTIL TRENDS COME INTO BETTER FOCUS. FOR REMAINING TERMINALS FOCUS
IS ON NWD ADVANCING SHRA THAT ARE SPREADING SLOWLY OVER SRN OK AS MID
LVL CYCLONE MOVES SLOWLY E OVER SRN PLAINS. WOULD NOT EXPECT SHRA TO
REACH SC & SE KS TIL ~12/00Z & AS SUCH HAVE LEFT OUT OF KICT & KCNU
TAFS FOR NOW..BUT WILL CERTAINLY MONITOR DOPPLER TRENDS THIS AFTERNOON
& UPDATE AS NEEDED. ALL TERMINALS SHOULD MAINTAIN VFR STATUS FOR MOST
OF 12Z TAF CYCLE.
PREV DISCUSSION... /ISSUED 320 AM CDT FRI MAY 11 2012/
DISCUSSION...
FORECAST CHALLENGE...PRECIP/CONVECTIVE CHANCES OVER THE WEEKEND.
TODAY-SATURDAY
A RATHER STRONG LATE SPRING COLD FRONT ASSOCIATED WITH THE
NORTHERN STREAM UPPER TROF WILL CONTINUE TO MOVE SOUTH INTO KANSAS
TODAY...THOUGH DIURNALLY SLOWING A BIT AS IT MOVES INTO CENTRAL
KANSAS. MEANWHILE THE CLOSED UPPER LOW ACROSS WEST TEXAS WILL LIFT
NORTHEAST TOWARD SOUTHWEST OKLAHOMA. MODEST MOISTURE AND
INSTABILITY WILL BE PRESENT ACROSS MUCH OF THE AREA TOWARD PEAK
HEATING...WITH THE SURFACE COLD FRONT PROVIDING A FOCUS FOR
ISOLATED TO WIDELY SCATTERED CONVECTION BY LATE THIS
AFTERNOON/EVENING. ANOTHER AREA OF LIFT ON THE NORTHEAST QUAD OF
THE APPROACHING SOUTHERN PLAINS UPPER LOW MAY ALSO RESULT IN SOME
CONVECTION SPREADING NORTH FROM OKLAHOMA INTO PORTIONS OF SOUTH
CENTRAL/SOUTHEAST KANSAS. IN THIS REGARD ONLY SLIGHT TWEAKS TO THE
GOING FORECAST WERE MADE TO POPS AND MAX TEMPERATURES TODAY. WILL
CONTINUE TO SHOW MODEST CHANCE POPS INTO TONIGHT AND SATURDAY AS
THE COLD FRONT/COOLER AIR CONTINUES TO OOZE SOUTH ACROSS THE REST
OF THE AREA AND THE UPPER LOW LIFTS NORTHEAST ACROSS OKLAHOMA TO
THE OZARKS.
SATURDAY NIGHT-SUNDAY
SHORT TERM MODEL TRENDS AND FORECAST CONSENSUS SUPPORTS A BIT
MORE DRYING AS THE COOLER AIR SETTLES IN DURING THE LATTER HALF
OF THE WEEKEND...AS A TRAILING SHORTWAVE DROPPING SOUTHEAST FROM
THE ROCKIES ACROSS THE CENTRAL HIGH PLAINS. THEREFORE HAVE REDUCED
OR REMOVED POPS IN SOME AREAS BY SATURDAY NIGHT AND SUNDAY.
OTHERWISE WILL KEEP MAXS A BIT BELOW MID-MAY CLIMO.
MONDAY-THURSDAY
LITTLE CHANGE TO THE OUTER PERIODS OF THE FORECAST WITH THE MAIN
STORM TRACK/STRONGER WESTERLIES STAYING WELL NORTH OF THE AREA
WITH A GRADUAL WARMING TREND BACK TO AND SLIGHTLY ABOVE CLIMO BY
THE MIDDLE OF NEXT WEEK.
DARMOFAL
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 76 55 68 54 / 20 30 30 20
HUTCHINSON 78 52 67 51 / 10 20 30 10
NEWTON 78 54 66 51 / 10 20 30 10
ELDORADO 76 55 68 52 / 20 40 50 20
WINFIELD-KWLD 75 56 69 54 / 50 50 50 20
RUSSELL 78 48 67 49 / 20 20 20 10
GREAT BEND 79 48 66 50 / 20 30 20 10
SALINA 79 51 69 50 / 20 30 30 10
MCPHERSON 78 52 67 51 / 10 20 30 10
COFFEYVILLE 76 58 68 56 / 50 60 60 30
CHANUTE 77 57 69 54 / 30 60 60 20
IOLA 77 57 69 54 / 20 60 60 20
PARSONS-KPPF 76 58 70 54 / 40 60 60 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1101 AM CDT FRI MAY 11 2012
.UPDATE...
UPDATED THE FORECAST TO INCREASE POPS OVER FAR SOUTH-CENTRAL AND
SOUTHEAST KANSAS THIS AFTERNOON...AS NORTHERN-MOST LOBE OF ENERGY
ASSOCIATED WITH SOUTHERN PLAINS UPPER LOW ROTATES NORTHWARD.
THINKING COVERAGE WILL BE DECENT AFTER 4 PM...ESPECIALLY SOUTH OF
HIGHWAYS 54/400. THE LATEST HRRR MODEL SEEMED TO HAVE A GOOD FEEL
FOR CURRENT AND EXPECTED PRECIPITATION COVERAGE. ADDITIONALLY...AN
ISOLATED SHOWER/THUNDERSTORM OR TWO WILL BE POSSIBLE AFTER 4-5 PM
OVER CENTRAL KANSAS ALONG A COLD FRONT APPROACHING FROM THE
NORTHWEST...ALSO SUPPORTED BY THE HRRR. IN ALL INSTANCES...NOT
ANTICIPATING SEVERE WEATHER DUE TO MEAGER INSTABILITY AND FORCING.
ADK
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT FRI MAY 11 2012/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
PRIMARY FOCUS THIS MORNING IS ON SE PROGRESS OF COLD FRONT THAT HAS
ENTERED NW KS ~09Z. FRONT APPEARS TO BE DECELERATING & AS SUCH WOULD
EXPECT ONLY KRSL TO EXPERIENCE COLD FRONTAL PASSAGE THIS MORNING WITH
WINDS BECOMING NE 13-17KTS THIS AFTERNOON. A FEW -SHRA POSSIBLE OVER
CNTRL KS ALONG THE FRONT BUT LIMITED COVERAGE DICTATES LEAVING OUT OF
TAF UNTIL TRENDS COME INTO BETTER FOCUS. FOR REMAINING TERMINALS FOCUS
IS ON NWD ADVANCING SHRA THAT ARE SPREADING SLOWLY OVER SRN OK AS MID
LVL CYCLONE MOVES SLOWLY E OVER SRN PLAINS. WOULD NOT EXPECT SHRA TO
REACH SC & SE KS TIL ~12/00Z & AS SUCH HAVE LEFT OUT OF KICT & KCNU
TAFS FOR NOW..BUT WILL CERTAINLY MONITOR DOPPLER TRENDS THIS AFTERNOON
& UPDATE AS NEEDED. ALL TERMINALS SHOULD MAINTAIN VFR STATUS FOR MOST
OF 12Z TAF CYCLE.
PREV DISCUSSION... /ISSUED 320 AM CDT FRI MAY 11 2012/
DISCUSSION...
FORECAST CHALLENGE...PRECIP/CONVECTIVE CHANCES OVER THE WEEKEND.
TODAY-SATURDAY
A RATHER STRONG LATE SPRING COLD FRONT ASSOCIATED WITH THE
NORTHERN STREAM UPPER TROF WILL CONTINUE TO MOVE SOUTH INTO KANSAS
TODAY...THOUGH DIURNALLY SLOWING A BIT AS IT MOVES INTO CENTRAL
KANSAS. MEANWHILE THE CLOSED UPPER LOW ACROSS WEST TEXAS WILL LIFT
NORTHEAST TOWARD SOUTHWEST OKLAHOMA. MODEST MOISTURE AND
INSTABILITY WILL BE PRESENT ACROSS MUCH OF THE AREA TOWARD PEAK
HEATING...WITH THE SURFACE COLD FRONT PROVIDING A FOCUS FOR
ISOLATED TO WIDELY SCATTERED CONVECTION BY LATE THIS
AFTERNOON/EVENING. ANOTHER AREA OF LIFT ON THE NORTHEAST QUAD OF
THE APPROACHING SOUTHERN PLAINS UPPER LOW MAY ALSO RESULT IN SOME
CONVECTION SPREADING NORTH FROM OKLAHOMA INTO PORTIONS OF SOUTH
CENTRAL/SOUTHEAST KANSAS. IN THIS REGARD ONLY SLIGHT TWEAKS TO THE
GOING FORECAST WERE MADE TO POPS AND MAX TEMPERATURES TODAY. WILL
CONTINUE TO SHOW MODEST CHANCE POPS INTO TONIGHT AND SATURDAY AS
THE COLD FRONT/COOLER AIR CONTINUES TO OOZE SOUTH ACROSS THE REST
OF THE AREA AND THE UPPER LOW LIFTS NORTHEAST ACROSS OKLAHOMA TO
THE OZARKS.
SATURDAY NIGHT-SUNDAY
SHORT TERM MODEL TRENDS AND FORECAST CONSENSUS SUPPORTS A BIT
MORE DRYING AS THE COOLER AIR SETTLES IN DURING THE LATTER HALF
OF THE WEEKEND...AS A TRAILING SHORTWAVE DROPPING SOUTHEAST FROM
THE ROCKIES ACROSS THE CENTRAL HIGH PLAINS. THEREFORE HAVE REDUCED
OR REMOVED POPS IN SOME AREAS BY SATURDAY NIGHT AND SUNDAY.
OTHERWISE WILL KEEP MAXS A BIT BELOW MID-MAY CLIMO.
MONDAY-THURSDAY
LITTLE CHANGE TO THE OUTER PERIODS OF THE FORECAST WITH THE MAIN
STORM TRACK/STRONGER WESTERLIES STAYING WELL NORTH OF THE AREA
WITH A GRADUAL WARMING TREND BACK TO AND SLIGHTLY ABOVE CLIMO BY
THE MIDDLE OF NEXT WEEK.
DARMOFAL
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 76 55 69 54 / 20 20 30 20
HUTCHINSON 78 53 68 51 / 10 20 30 20
NEWTON 78 54 68 51 / 10 20 30 20
ELDORADO 76 55 69 52 / 20 20 30 20
WINFIELD-KWLD 75 56 70 54 / 50 30 40 20
RUSSELL 78 50 65 49 / 20 20 30 20
GREAT BEND 79 51 67 50 / 20 30 30 20
SALINA 79 52 69 50 / 20 30 30 10
MCPHERSON 78 53 68 51 / 10 20 30 20
COFFEYVILLE 76 58 71 56 / 50 40 50 30
CHANUTE 77 57 70 54 / 30 30 40 20
IOLA 77 57 70 54 / 20 30 40 20
PARSONS-KPPF 76 58 71 54 / 40 30 50 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
201 PM EDT FRI MAY 11 2012
.UPDATE...
ISSUED AT 1049 AM EDT FRI MAY 11 2012
COLD FRONT LURKING UPSTREAM NEAR DULUTH...BUT FRONT IS PUSHING INTO
UPPER RIDGE SO IT WILL BE SLOW TO ARRIVE THIS AFTN. AVAILABLE RADARS
UPSTREAM /DLH RADAR STILL DOWN TO DUAL POL INSTALLATION/ AND SFC OBS
INDICATE SHOWERS ARE MAINLY WEST OF DLH STILL. SHOWERS ARE LINING UP
WELL WITH H85-H7 FRONTOGENESIS AND HIGHER H7 DWPNTS. THESE MECHANISMS
FCST TO SLIDE INTO FAR WEST CWA AFT 18Z AND MORE INTO CNTRL CWA
TOWARD 00Z. NO REAL CHANGE TO PREVIOUS FCST WRT POPS/WX...JUST
DELAYED ONSET OF CHANCE POPS THIS AFTN IN THE WEST BY A COUPLE
HOURS. NUDGED HIGHS UP INTO UPR 70S AND EVEN PUT SOME 80 DEGREE
READINGS IN OVR PORTIONS OF CNTRL CWA. THIS RAISES A CONCERN WITH
FIRE WX AS FCST TEMPS/DWPNTS/RH AND WINDS ARE NOW NEAR CRITICAL
CONDITIONS. NOT QUITE THERE THOUGH. COORDINATED WITH MIDNR AND
ISSUED WILDFIRE POTENTIAL STATEMENT FOR PORTIONS OF CNTRL CWA
/DICKINSON AND MENOMINEE COUNTIES THROUGH MARQUETTE COUNTY/.
WILDFIRE POTENTIAL SHOULD FADE BY LATE THIS AFTN WITH INCREASING
CLOUDS JUST AHEAD OF THE FRONT.
&&
.SYNOPSIS...
ISSUED AT 459 AM EDT FRI MAY 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM N
CNTRL CANADA THROUGH SASK INTO ERN MONTANA AND A DOWNSTREAM RIDGE
FROM THE UPPER MS VALLEY TO HUDSON BAY. AT THE SFC...A COLD FRONT
STRETCHED FROM NW ONTARIO THROUGH NW MN INTO SE SD. INCREASING SRLY
WINDS OVER MN/IA HAD BROUGH SOME ADDITIONAL MOISTURE INTO THE REGION
WITH DEWPOINTS INTO THE MID AND UPPER 40S OVER SRN MN. A BAND OF
SHRA AND SOME ISOLD TSRA CONTINUED BEHIND THE FRONT SUPPORTED BY
800-600 MB FGEN OVER THE ERN DAKOTAS WHILE LIGHT RADAR RETURNS OVER
WRN MN WERE DIMINISHING AS THEY MOVED INTO DRIER AIR TO THE EAST.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 459 AM EDT FRI MAY 11 2012
MODELS HAVE TRENDED SLIGHTLY SLOWER WITH THE MOVEMENT OF THE FRONT
WITH THE NAM AND REGIONAL GEM BRINGING INTO THE WEST BTWN 18Z-21Z
AND THROUGH CNTRL UPPER MI BTWN 00Z-03Z. THE STRONGEST 800-600 MB
FGEN AND FORCING WITH THE RIGHT ENTRANCE OF THE 250 MB JET IS
EXPECTED TO SLIDE FROM MN NE INTO NW ONTARIO...REMAINING TO THE NW
OF THE CWA. INITIAL PCPN CHANCES ARE EXPECTED WITH LOW LEVEL CONV
ALONG THE FRONT DURING THE LATE AFTERNOON. ALTHOUGH DEWPOINTS SHOULD
EVENTUALLY CLIMB INTO THE MID AND UPPER 40S OVER NW WI INTO SW UPPER
MI...ONLY MODEST MLCAPE VALUES NEAR 400 J/KG WILL BE AVBL INTO THE
SOUTHERN PORTION OF THE CWA. WITH ONLY LIMITED INSTABILITY AND LACK
OF STRONGER DYNAMICS...KEPT POPS IN THE CHANCE/SCT RANGE. ALTHOUGH
THERE MAY STILL BE A PERIOD OF POST-FRONTAL FGEN SUPPORTED PCPN
LATER IN THE EVENING...PER REGIONAL GEM AND LCL HIGH RES WRF/ARW...
ESPECIALLY OVER THE NW HALF...EXPECT RAIN TO END BY AROUND 06Z.
SUNSHINE/MIXING INTO THE EARLY AFTERNON SHOULD HELP TEMPS CLIMB INTO
THE MID 70S OVER THE WEST HALF OF THE CWA WITH COOLER READINGS ONLY
IN THE UPPER 50S NEAR LAKE MICHIGAN. WITH MOISTURE ARRIVING...MAINLY
LATE IN THE DAY...RH VALUES COULD DROP AOB 30 PCT OVER THE INLAND
EAST HALF.
A PLEASANT DAY WITH ABUNDANT SUN WILL PREVAIL SATURDAY. COOLER AIR
INTO THE REGION 850 MB TEMPS IN THE 3C-5C RANGE WILL STILL ALLOW
TEMPS TO CLIMB ABOVE SEASONAL AVERAGES INTO THE MID 60S.
.LONG TERM...(AFTER MIDNIGHT SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 731 AM EDT FRI MAY 11 2012
COLD FRONT AND SHORTWAVE MOVING THROUGH TODAY AND TONIGHT WILL
USHER THE REGION INTO A FAIRLY DRY NW FLOW ALOFT PATTERN FOR THE
LONG TERM FORECAST.
SAT NIGHT...HIGH PRESSURE RIDGE AXIS SLIDING MORE OVER THE
CNTRL/LOWER GREAT LKS. LINGERING LIGHT WINDS COULD END UP PRODUCING
SOME COOL LOWS...EXCEPT OVER THE FAR WEST AND NEAR THE
KEWEENAW...WHERE THE PRESSURE GRADIENT WILL BE INCREASING AHEAD OF
AN APPROACHING COLD FRONT. WITH PWATS AROUND 55 PERCENT OF
NORMAL...COULD SEE SOME NEAR FREEZING TEMPS OVER/AROUND IRON
COUNTY.
SUN...COLD FRONT ASSOCIATED WITH LOW CENTERED OVER SRN HUDSON BAY
WILL BE MOVING THROUGH SW ONTARIO WILL PRODUCE AN INCREASING
PRESSURE GRADIENT AND SHIFT WINDS A LITTLE MORE OUT OF THE SW. THE
DEEP MIXING TO H750 WILL LEAD TO GUSTS IN THE 15-20KT
RANGE...MAINLY OVER THE WEST HALF. THIS WILL ALSO PRODUCE HIGHS IN
THE UPPER 60S AND LOWER 70S AWAY FROM THE COOLING DOWNSTREAM OF LK
MI. DRY AIR SHOULD BE IN PLACE...BUT THERE ARE HINTS IN THE MODELS
THAT THERE COULD BE SOME HIGH BASED DIURNAL CU /NAM/ AND THEN MID
CLOUDS OVERSPREADING THE NW HALF OF THE CWA AHEAD OF THE COLD FRONT
AND WEAK SHORTWAVE. THINKING THE DRIER AIR WILL WIN OUT FOR MUCH OF
THE DAY AND STAYED WITH MOSTLY SUNNY. THIS DEEP MIXING WILL LEAD TO
ANOTHER DAY OF LOW DEWPOINTS/RH. ONLY MADE MINOR TWEAKS DOWN TO
GOING DEWPOINT FORECAST AND STILL HAVE MIN RH VALUES IN THE UPPER
TEENS AND 20S. THIS WILL LEAD TO SOME FIRE WX CONCERNS...ESPECIALLY
OVER THE WRN CWA WHERE THE WINDS WILL BE STRONGEST WITH THE WARMEST
TEMPS AND LOWEST RH VALUES.
WITH THE BEST SHORTWAVE ENERGY...MOISTURE...AND LLVL CAA STAYING TO
THE NE OF THE CWA...ONLY EXPECT SOME MID CLOUDS TO PUSH ACROSS THE
CWA ON SUN NIGHT. THESE CLOUDS...ALONG WITH AN INCREASED PRESSURE
GRADIENT FROM THE FRONT WILL WILL KEEP WINDS UP THROUGH THE NIGHT
AND LIMIT TEMP FALL. THUS...WILL KEEP LOWS ABOVE NORMAL AND IN THE
MID/UPPER 40S.
MON THROUGH THURS...NW FLOW ALOFT REMAINS OVER THE AREA THROUGH THE
EXTENDED PART OF THE FORECAST. PERSISTENT HIGH OVER THE CNTRL
PLAINS WILL SFC RIDGE TO THE S OF THE CWA ON MON AS NEXT SHORTWAVE
AND ASSOCIATED COLD FRONT TRY TO APPROACH THE AREA ON TUES.
MODELS VARY ON THE INTENSITY OF THIS NEXT SHORTWAVE AND COLD
FRONT MOVING MOVING THROUGH ON TUES NIGHT AND WED MORNING. 12Z ECMWF
SHOWING MORE MOISTURE WITH THIS SYSTEM AND A STRONGER
SHORTWAVE...BUT ONCE AGAIN THE BEST FEATURES LOOK TO BE OVER LK
SUPERIOR OR SRN ONTARIO. 00Z GFS IS ON THE WEAK SIDE...WHILE
THE 00Z GEM IS BETWEEN THE TWO AND SEEMS LIKE A GOOD
COMPROMISE. EVEN IN THIS CASE...CAN/T JUSTIFY MORE THAN SLIGHT
CHANCES AND WILL KEEP THE GOING FORECAST.
OTHERWISE...MODELS TRENDING TOWARDS LOW DEVELOPING IN THE NRN PLAINS
WED NIGHT INTO THURS. 00Z GFS IS THE FASTEST SOLN...BUT 00Z GEM
ENS MEAN AND 12Z ECMWF HOLD THE LOW BACK IN THE NRN PLAINS AT 12Z
THURS AND WILL FOLLOW THAT SOLN. THIS COULD PUSH SOME WAA PCPN INTO
THE AREA ON THURS AHEAD OF THE WARM FRONT IN MN/WI AND WILL MAINLY
MENTION SLIGHT CHANCES.
OVERALL...EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM
PERIOD...WITH HIGHS IN THE 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 200 PM EDT FRI MAY 11 2012
DECENT HEATING TODAY HAS ALLOWED FOR SUFFICIENT MIXING TO BRING DOWN
GUSTY WINDS TO THE SFC...ESPECIALLY AT SAW. A COLD FRONT CURRENTLY
NEAR IWD WILL CONTINUE EAST THROUGH THE AFTERNOON...REACHING CMX BY
20Z AND SAW BY 00Z. EXPECT A QUICK WIND SHIFT FROM S/SW TO NW WITH
THIS FRONT...WITH SPEEDS HOVERING AROUND 12KTS. LATEST OBSERVATIONS
AND MODEL TRENDS ARE STARTING TO INDICATE THAT MOISTURE IS EVEN MORE
SCARCE WITH THIS FRONT THAN THOUGHT AS IT TRIES TO MOVE UNDER A
MID-LEVEL RIDGE. CIGS SHOULD COME DOWN AT ALL SITES AND -SHRA SHOULD
MOVE IN FOR ABOUT A 6 HOUR PERIOD AFTER THE FRONT PASSES...BUT
MOISTURE DEFICIENCY MAY END UP KEEPING ALL SITES IN VFR RANGE. FOR
THE TIME BEING...KEPT MVFR CIGS AT IWD AND CMX IN THE FORECAST DUE
TO POTENTIAL FOR UPSLOPE ENHANCEMENT. MUCH DRIER AIR MOVING IN
LATE TONIGHT WILL ERODE CLOUDS FROM WEST TO EAST AND RESULT IN A
MOSTLY CLEAR SKIES AND LIGHT WINDS INTO SATURDAY AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 731 AM EDT FRI MAY 11 2012
AN APPROACHING COLD FRONT WILL INCREASE SRLY WINDS THIS
MORNING...BUT THE MARINE LAYER SHOULD KEEP WINDS BELOW 20KTS.
BEHIND THE FRONT...THERE COULD BE A BRIEF PERIOD OF NW WINDS TO
20 AND POSSIBLY 25KTS LATE TONIGHT. AS LAKE SUPERIOR BECOMES
STATIONED BETWEEN LOW PRESSURE NEAR HUDSON BAY AND HIGH PRESSURE IN
THE CENTRAL PLAINS...PERSISTENT WRLY FLOW WILL BE IN PLACE THROUGH
MON AND WINDS AT MOST LOCATIONS WILL REMAIN BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...TK
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1105 AM EDT FRI MAY 11 2012
.UPDATE...
ISSUED AT 1049 AM EDT FRI MAY 11 2012
COLD FRONT LURKING UPSTREAM NEAR DULUTH...BUT FRONT IS PUSHING INTO
UPPER RIDGE SO IT WILL BE SLOW TO ARRIVE THIS AFTN. AVAILABLE RADARS
UPSTREAM /DLH RADAR STILL DOWN TO DUAL POL INSTALLATION/ AND SFC OBS
INDICATE SHOWERS ARE MAINLY WEST OF DLH STILL. SHOWERS ARE LINING UP
WELL WITH H85-H7 FRONTOGENESIS AND HIGHER H7 DWPNTS. THESE MECHANISMS
FCST TO SLIDE INTO FAR WEST CWA AFT 18Z AND MORE INTO CNTRL CWA
TOWARD 00Z. NO REAL CHANGE TO PREVIOUS FCST WRT POPS/WX...JUST
DELAYED ONSET OF CHANCE POPS THIS AFTN IN THE WEST BY A COUPLE
HOURS. NUDGED HIGHS UP INTO UPR 70S AND EVEN PUT SOME 80 DEGREE
READINGS IN OVR PORTIONS OF CNTRL CWA. THIS RAISES A CONCERN WITH
FIRE WX AS FCST TEMPS/DWPNTS/RH AND WINDS ARE NOW NEAR CRITICAL
CONDITIONS. NOT QUITE THERE THOUGH. COORDINATED WITH MIDNR AND
ISSUED WILDFIRE POTENTIAL STATEMENT FOR PORTIONS OF CNTRL CWA
/DICKINSON AND MENOMINEE COUNTIES THROUGH MARQUETTE COUNTY/.
WILDFIRE POTENTIAL SHOULD FADE BY LATE THIS AFTN WITH INCREASING
CLOUDS JUST AHEAD OF THE FRONT.
&&
.SYNOPSIS...
ISSUED AT 459 AM EDT FRI MAY 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM N
CNTRL CANADA THROUGH SASK INTO ERN MONTANA AND A DOWNSTREAM RIDGE
FROM THE UPPER MS VALLEY TO HUDSON BAY. AT THE SFC...A COLD FRONT
STRETCHED FROM NW ONTARIO THROUGH NW MN INTO SE SD. INCREASING SRLY
WINDS OVER MN/IA HAD BROUGH SOME ADDITIONAL MOISTURE INTO THE REGION
WITH DEWPOINTS INTO THE MID AND UPPER 40S OVER SRN MN. A BAND OF
SHRA AND SOME ISOLD TSRA CONTINUED BEHIND THE FRONT SUPPORTED BY
800-600 MB FGEN OVER THE ERN DAKOTAS WHILE LIGHT RADAR RETURNS OVER
WRN MN WERE DIMINISHING AS THEY MOVED INTO DRIER AIR TO THE EAST.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 459 AM EDT FRI MAY 11 2012
MODELS HAVE TRENDED SLIGHTLY SLOWER WITH THE MOVEMENT OF THE FRONT
WITH THE NAM AND REGIONAL GEM BRINGING INTO THE WEST BTWN 18Z-21Z
AND THROUGH CNTRL UPPER MI BTWN 00Z-03Z. THE STRONGEST 800-600 MB
FGEN AND FORCING WITH THE RIGHT ENTRANCE OF THE 250 MB JET IS
EXPECTED TO SLIDE FROM MN NE INTO NW ONTARIO...REMAINING TO THE NW
OF THE CWA. INITIAL PCPN CHANCES ARE EXPECTED WITH LOW LEVEL CONV
ALONG THE FRONT DURING THE LATE AFTERNOON. ALTHOUGH DEWPOINTS SHOULD
EVENTUALLY CLIMB INTO THE MID AND UPPER 40S OVER NW WI INTO SW UPPER
MI...ONLY MODEST MLCAPE VALUES NEAR 400 J/KG WILL BE AVBL INTO THE
SOUTHERN PORTION OF THE CWA. WITH ONLY LIMITED INSTABILITY AND LACK
OF STRONGER DYNAMICS...KEPT POPS IN THE CHANCE/SCT RANGE. ALTHOUGH
THERE MAY STILL BE A PERIOD OF POST-FRONTAL FGEN SUPPORTED PCPN
LATER IN THE EVENING...PER REGIONAL GEM AND LCL HIGH RES WRF/ARW...
ESPECIALLY OVER THE NW HALF...EXPECT RAIN TO END BY AROUND 06Z.
SUNSHINE/MIXING INTO THE EARLY AFTERNON SHOULD HELP TEMPS CLIMB INTO
THE MID 70S OVER THE WEST HALF OF THE CWA WITH COOLER READINGS ONLY
IN THE UPPER 50S NEAR LAKE MICHIGAN. WITH MOISTURE ARRIVING...MAINLY
LATE IN THE DAY...RH VALUES COULD DROP AOB 30 PCT OVER THE INLAND
EAST HALF.
A PLEASANT DAY WITH ABUNDANT SUN WILL PREVAIL SATURDAY. COOLER AIR
INTO THE REGION 850 MB TEMPS IN THE 3C-5C RANGE WILL STILL ALLOW
TEMPS TO CLIMB ABOVE SEASONAL AVERAGES INTO THE MID 60S.
.LONG TERM...(AFTER MIDNIGHT SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 731 AM EDT FRI MAY 11 2012
COLD FRONT AND SHORTWAVE MOVING THROUGH TODAY AND TONIGHT WILL
USHER THE REGION INTO A FAIRLY DRY NW FLOW ALOFT PATTERN FOR THE
LONG TERM FORECAST.
SAT NIGHT...HIGH PRESSURE RIDGE AXIS SLIDING MORE OVER THE
CNTRL/LOWER GREAT LKS. LINGERING LIGHT WINDS COULD END UP PRODUCING
SOME COOL LOWS...EXCEPT OVER THE FAR WEST AND NEAR THE
KEWEENAW...WHERE THE PRESSURE GRADIENT WILL BE INCREASING AHEAD OF
AN APPROACHING COLD FRONT. WITH PWATS AROUND 55 PERCENT OF
NORMAL...COULD SEE SOME NEAR FREEZING TEMPS OVER/AROUND IRON
COUNTY.
SUN...COLD FRONT ASSOCIATED WITH LOW CENTERED OVER SRN HUDSON BAY
WILL BE MOVING THROUGH SW ONTARIO WILL PRODUCE AN INCREASING
PRESSURE GRADIENT AND SHIFT WINDS A LITTLE MORE OUT OF THE SW. THE
DEEP MIXING TO H750 WILL LEAD TO GUSTS IN THE 15-20KT
RANGE...MAINLY OVER THE WEST HALF. THIS WILL ALSO PRODUCE HIGHS IN
THE UPPER 60S AND LOWER 70S AWAY FROM THE COOLING DOWNSTREAM OF LK
MI. DRY AIR SHOULD BE IN PLACE...BUT THERE ARE HINTS IN THE MODELS
THAT THERE COULD BE SOME HIGH BASED DIURNAL CU /NAM/ AND THEN MID
CLOUDS OVERSPREADING THE NW HALF OF THE CWA AHEAD OF THE COLD FRONT
AND WEAK SHORTWAVE. THINKING THE DRIER AIR WILL WIN OUT FOR MUCH OF
THE DAY AND STAYED WITH MOSTLY SUNNY. THIS DEEP MIXING WILL LEAD TO
ANOTHER DAY OF LOW DEWPOINTS/RH. ONLY MADE MINOR TWEAKS DOWN TO
GOING DEWPOINT FORECAST AND STILL HAVE MIN RH VALUES IN THE UPPER
TEENS AND 20S. THIS WILL LEAD TO SOME FIRE WX CONCERNS...ESPECIALLY
OVER THE WRN CWA WHERE THE WINDS WILL BE STRONGEST WITH THE WARMEST
TEMPS AND LOWEST RH VALUES.
WITH THE BEST SHORTWAVE ENERGY...MOISTURE...AND LLVL CAA STAYING TO
THE NE OF THE CWA...ONLY EXPECT SOME MID CLOUDS TO PUSH ACROSS THE
CWA ON SUN NIGHT. THESE CLOUDS...ALONG WITH AN INCREASED PRESSURE
GRADIENT FROM THE FRONT WILL WILL KEEP WINDS UP THROUGH THE NIGHT
AND LIMIT TEMP FALL. THUS...WILL KEEP LOWS ABOVE NORMAL AND IN THE
MID/UPPER 40S.
MON THROUGH THURS...NW FLOW ALOFT REMAINS OVER THE AREA THROUGH THE
EXTENDED PART OF THE FORECAST. PERSISTENT HIGH OVER THE CNTRL
PLAINS WILL SFC RIDGE TO THE S OF THE CWA ON MON AS NEXT SHORTWAVE
AND ASSOCIATED COLD FRONT TRY TO APPROACH THE AREA ON TUES.
MODELS VARY ON THE INTENSITY OF THIS NEXT SHORTWAVE AND COLD
FRONT MOVING MOVING THROUGH ON TUES NIGHT AND WED MORNING. 12Z ECMWF
SHOWING MORE MOISTURE WITH THIS SYSTEM AND A STRONGER
SHORTWAVE...BUT ONCE AGAIN THE BEST FEATURES LOOK TO BE OVER LK
SUPERIOR OR SRN ONTARIO. 00Z GFS IS ON THE WEAK SIDE...WHILE
THE 00Z GEM IS BETWEEN THE TWO AND SEEMS LIKE A GOOD
COMPROMISE. EVEN IN THIS CASE...CAN/T JUSTIFY MORE THAN SLIGHT
CHANCES AND WILL KEEP THE GOING FORECAST.
OTHERWISE...MODELS TRENDING TOWARDS LOW DEVELOPING IN THE NRN PLAINS
WED NIGHT INTO THURS. 00Z GFS IS THE FASTEST SOLN...BUT 00Z GEM
ENS MEAN AND 12Z ECMWF HOLD THE LOW BACK IN THE NRN PLAINS AT 12Z
THURS AND WILL FOLLOW THAT SOLN. THIS COULD PUSH SOME WAA PCPN INTO
THE AREA ON THURS AHEAD OF THE WARM FRONT IN MN/WI AND WILL MAINLY
MENTION SLIGHT CHANCES.
OVERALL...EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM
PERIOD...WITH HIGHS IN THE 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 731 AM EDT FRI MAY 11 2012
EXPECT DRY HI PRES OVER THE LOWER GREAT LAKES TO MAINTAIN VFR
CONDITIONS ACROSS UPPER MICHIGAN THIS MORNING. A GUSTY S WIND BTWN
THIS DEPARTING HI AND AN APRCHG COLD FRONT WILL DEVELOP AFTER SUNRISE WITH
SOME DAYTIME HEATING/MIXING...ESPECIALLY AT THE MORE EXPOSED IWD/SAW
LOCATIONS. HOWEVER...LINGERING DRYNESS WL MAINTAIN VFR CONDITIONS.
EXPECT A SHARP WIND SHIFT FOLLOWING THE MID TO LATE AFTERNOON FROPA
AT CMX/IWD...AND SOME -SHRA FOR A PERIOD OF MVFR CONDITIONS ARE
LIKELY AT THESE 2 SITES AFTER THE FROPA WITH UPSLOPE WNW FLOW. THE
MORE EXPOSED CMX LOCATION SHOULD ALSO SEE GUSTY WNW WINDS FOLLOWING
THE FROPA. AT SAW...THE FROPA/-SHRA WL NOT OCCUR UNTIL SHORTLY
AFTER 12/00Z...BUT VFR CONDITIONS SHOULD PREVAIL THERE WITH
DOWNSLOPE FLOW. DRIER AIR MOVING IN OVERNIGHT WILL BRING CLEARING
AND VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 731 AM EDT FRI MAY 11 2012
AN APPROACHING COLD FRONT WILL INCREASE SRLY WINDS THIS
MORNING...BUT THE MARINE LAYER SHOULD KEEP WINDS BELOW 20KTS.
BEHIND THE FRONT...THERE COULD BE A BRIEF PERIOD OF NW WINDS TO
20 AND POSSIBLY 25KTS LATE TONIGHT. AS LAKE SUPERIOR BECOMES
STATIONED BETWEEN LOW PRESSURE NEAR HUDSON BAY AND HIGH PRESSURE IN
THE CENTRAL PLAINS...PERSISTENT WRLY FLOW WILL BE IN PLACE THROUGH
MON AND WINDS AT MOST LOCATIONS WILL REMAIN BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
732 AM EDT FRI MAY 11 2012
.SYNOPSIS...
ISSUED AT 459 AM EDT FRI MAY 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM N
CNTRL CANADA THROUGH SASK INTO ERN MONTANA AND A DOWNSTREAM RIDGE
FROM THE UPPER MS VALLEY TO HUDSON BAY. AT THE SFC...A COLD FRONT
STRETCHED FROM NW ONTARIO THROUGH NW MN INTO SE SD. INCREASING SRLY
WINDS OVER MN/IA HAD BROUGH SOME ADDITIONAL MOISTURE INTO THE REGION
WITH DEWPOINTS INTO THE MID AND UPPER 40S OVER SRN MN. A BAND OF
SHRA AND SOME ISOLD TSRA CONTINUED BEHIND THE FRONT SUPPORTED BY
800-600 MB FGEN OVER THE ERN DAKOTAS WHILE LIGHT RADAR RETURNS OVER
WRN MN WERE DIMINISHING AS THEY MOVED INTO DRIER AIR TO THE EAST.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 459 AM EDT FRI MAY 11 2012
MODELS HAVE TRENDED SLIGHTLY SLOWER WITH THE MOVEMENT OF THE FRONT
WITH THE NAM AND REGIONAL GEM BRINGING INTO THE WEST BTWN 18Z-21Z
AND THROUGH CNTRL UPPER MI BTWN 00Z-03Z. THE STRONGEST 800-600 MB
FGEN AND FORCING WITH THE RIGHT ENTRANCE OF THE 250 MB JET IS
EXPECTED TO SLIDE FROM MN NE INTO NW ONTARIO...REMAINING TO THE NW
OF THE CWA. INITIAL PCPN CHANCES ARE EXPECTED WITH LOW LEVEL CONV
ALONG THE FRONT DURING THE LATE AFTERNOON. ALTHOUGH DEWPOINTS SHOULD
EVENTUALLY CLIMB INTO THE MID AND UPPER 40S OVER NW WI INTO SW UPPER
MI...ONLY MODEST MLCAPE VALUES NEAR 400 J/KG WILL BE AVBL INTO THE
SOUTHERN PORTION OF THE CWA. WITH ONLY LIMITED INSTABILITY AND LACK
OF STRONGER DYNAMICS...KEPT POPS IN THE CHANCE/SCT RANGE. ALTHOUGH
THERE MAY STILL BE A PERIOD OF POST-FRONTAL FGEN SUPPORTED PCPN
LATER IN THE EVENING...PER REGIONAL GEM AND LCL HIGH RES WRF/ARW...
ESPECIALLY OVER THE NW HALF...EXPECT RAIN TO END BY AROUND 06Z.
SUNSHINE/MIXING INTO THE EARLY AFTERNON SHOULD HELP TEMPS CLIMB INTO
THE MID 70S OVER THE WEST HALF OF THE CWA WITH COOLER READINGS ONLY
IN THE UPPER 50S NEAR LAKE MICHIGAN. WITH MOISTURE ARRIVING...MAINLY
LATE IN THE DAY...RH VALUES COULD DROP AOB 30 PCT OVER THE INLAND
EAST HALF.
A PLEASANT DAY WITH ABUNDANT SUN WILL PREVAIL SATURDAY. COOLER AIR
INTO THE REGION 850 MB TEMPS IN THE 3C-5C RANGE WILL STILL ALLOW
TEMPS TO CLIMB ABOVE SEASONAL AVERAGES INTO THE MID 60S.
.LONG TERM...(AFTER MIDNIGHT SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 731 AM EDT FRI MAY 11 2012
COLD FRONT AND SHORTWAVE MOVING THROUGH TODAY AND TONIGHT WILL
USHER THE REGION INTO A FAIRLY DRY NW FLOW ALOFT PATTERN FOR THE
LONG TERM FORECAST.
SAT NIGHT...HIGH PRESSURE RIDGE AXIS SLIDING MORE OVER THE
CNTRL/LOWER GREAT LKS. LINGERING LIGHT WINDS COULD END UP PRODUCING
SOME COOL LOWS...EXCEPT OVER THE FAR WEST AND NEAR THE
KEWEENAW...WHERE THE PRESSURE GRADIENT WILL BE INCREASING AHEAD OF
AN APPROACHING COLD FRONT. WITH PWATS AROUND 55 PERCENT OF
NORMAL...COULD SEE SOME NEAR FREEZING TEMPS OVER/AROUND IRON
COUNTY.
SUN...COLD FRONT ASSOCIATED WITH LOW CENTERED OVER SRN HUDSON BAY
WILL BE MOVING THROUGH SW ONTARIO WILL PRODUCE AN INCREASING
PRESSURE GRADIENT AND SHIFT WINDS A LITTLE MORE OUT OF THE SW. THE
DEEP MIXING TO H750 WILL LEAD TO GUSTS IN THE 15-20KT
RANGE...MAINLY OVER THE WEST HALF. THIS WILL ALSO PRODUCE HIGHS IN
THE UPPER 60S AND LOWER 70S AWAY FROM THE COOLING DOWNSTREAM OF LK
MI. DRY AIR SHOULD BE IN PLACE...BUT THERE ARE HINTS IN THE MODELS
THAT THERE COULD BE SOME HIGH BASED DIURNAL CU /NAM/ AND THEN MID
CLOUDS OVERSPREADING THE NW HALF OF THE CWA AHEAD OF THE COLD FRONT
AND WEAK SHORTWAVE. THINKING THE DRIER AIR WILL WIN OUT FOR MUCH OF
THE DAY AND STAYED WITH MOSTLY SUNNY. THIS DEEP MIXING WILL LEAD TO
ANOTHER DAY OF LOW DEWPOINTS/RH. ONLY MADE MINOR TWEAKS DOWN TO
GOING DEWPOINT FORECAST AND STILL HAVE MIN RH VALUES IN THE UPPER
TEENS AND 20S. THIS WILL LEAD TO SOME FIRE WX CONCERNS...ESPECIALLY
OVER THE WRN CWA WHERE THE WINDS WILL BE STRONGEST WITH THE WARMEST
TEMPS AND LOWEST RH VALUES.
WITH THE BEST SHORTWAVE ENERGY...MOISTURE...AND LLVL CAA STAYING TO
THE NE OF THE CWA...ONLY EXPECT SOME MID CLOUDS TO PUSH ACROSS THE
CWA ON SUN NIGHT. THESE CLOUDS...ALONG WITH AN INCREASED PRESSURE
GRADIENT FROM THE FRONT WILL WILL KEEP WINDS UP THROUGH THE NIGHT
AND LIMIT TEMP FALL. THUS...WILL KEEP LOWS ABOVE NORMAL AND IN THE
MID/UPPER 40S.
MON THROUGH THURS...NW FLOW ALOFT REMAINS OVER THE AREA THROUGH THE
EXTENDED PART OF THE FORECAST. PERSISTENT HIGH OVER THE CNTRL
PLAINS WILL SFC RIDGE TO THE S OF THE CWA ON MON AS NEXT SHORTWAVE
AND ASSOCIATED COLD FRONT TRY TO APPROACH THE AREA ON TUES.
MODELS VARY ON THE INTENSITY OF THIS NEXT SHORTWAVE AND COLD
FRONT MOVING MOVING THROUGH ON TUES NIGHT AND WED MORNING. 12Z ECMWF
SHOWING MORE MOISTURE WITH THIS SYSTEM AND A STRONGER
SHORTWAVE...BUT ONCE AGAIN THE BEST FEATURES LOOK TO BE OVER LK
SUPERIOR OR SRN ONTARIO. 00Z GFS IS ON THE WEAK SIDE...WHILE
THE 00Z GEM IS BETWEEN THE TWO AND SEEMS LIKE A GOOD
COMPROMISE. EVEN IN THIS CASE...CAN/T JUSTIFY MORE THAN SLIGHT
CHANCES AND WILL KEEP THE GOING FORECAST.
OTHERWISE...MODELS TRENDING TOWARDS LOW DEVELOPING IN THE NRN PLAINS
WED NIGHT INTO THURS. 00Z GFS IS THE FASTEST SOLN...BUT 00Z GEM
ENS MEAN AND 12Z ECMWF HOLD THE LOW BACK IN THE NRN PLAINS AT 12Z
THURS AND WILL FOLLOW THAT SOLN. THIS COULD PUSH SOME WAA PCPN INTO
THE AREA ON THURS AHEAD OF THE WARM FRONT IN MN/WI AND WILL MAINLY
MENTION SLIGHT CHANCES.
OVERALL...EXPECT ABOVE NORMAL TEMPERATURES THROUGH THE LONG TERM
PERIOD...WITH HIGHS IN THE 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 731 AM EDT FRI MAY 11 2012
EXPECT DRY HI PRES OVER THE LOWER GREAT LAKES TO MAINTAIN VFR
CONDITIONS ACROSS UPPER MICHIGAN THIS MORNING. A GUSTY S WIND BTWN
THIS DEPARTING HI AND AN APRCHG COLD FRONT WILL DEVELOP AFTER SUNRISE WITH
SOME DAYTIME HEATING/MIXING...ESPECIALLY AT THE MORE EXPOSED IWD/SAW
LOCATIONS. HOWEVER...LINGERING DRYNESS WL MAINTAIN VFR CONDITIONS.
EXPECT A SHARP WIND SHIFT FOLLOWING THE MID TO LATE AFTERNOON FROPA
AT CMX/IWD...AND SOME -SHRA FOR A PERIOD OF MVFR CONDITIONS ARE
LIKELY AT THESE 2 SITES AFTER THE FROPA WITH UPSLOPE WNW FLOW. THE
MORE EXPOSED CMX LOCATION SHOULD ALSO SEE GUSTY WNW WINDS FOLLOWING
THE FROPA. AT SAW...THE FROPA/-SHRA WL NOT OCCUR UNTIL SHORTLY
AFTER 12/00Z...BUT VFR CONDITIONS SHOULD PREVAIL THERE WITH
DOWNSLOPE FLOW. DRIER AIR MOVING IN OVERNIGHT WILL BRING CLEARING
AND VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 731 AM EDT FRI MAY 11 2012
AN APPROACHING COLD FRONT WILL INCREASE SRLY WINDS THIS
MORNING...BUT THE MARINE LAYER SHOULD KEEP WINDS BELOW 20KTS.
BEHIND THE FRONT...THERE COULD BE A BRIEF PERIOD OF NW WINDS TO
20 AND POSSIBLY 25KTS LATE TONIGHT. AS LAKE SUPERIOR BECOMES
STATIONED BETWEEN LOW PRESSURE NEAR HUDSON BAY AND HIGH PRESSURE IN
THE CENTRAL PLAINS...PERSISTENT WRLY FLOW WILL BE IN PLACE THROUGH
MON AND WINDS AT MOST LOCATIONS WILL REMAIN BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
505 AM EDT FRI MAY 11 2012
.SYNOPSIS...
ISSUED AT 459 AM EDT FRI MAY 11 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM N
CNTRL CANADA THROUGH SASK INTO ERN MONTANA AND A DOWNSTREAM RIDGE
FROM THE UPPER MS VALLEY TO HUDSON BAY. AT THE SFC...A COLD FRONT
STRETCHED FROM NW ONTARIO THROUGH NW MN INTO SE SD. INCREASING SRLY
WINDS OVER MN/IA HAD BROUGH SOME ADDITIONAL MOISTURE INTO THE REGION
WITH DEWPOINTS INTO THE MID AND UPPER 40S OVER SRN MN. A BAND OF
SHRA AND SOME ISOLD TSRA CONTINUED BEHIND THE FRONT SUPPORTED BY
800-600 MB FGEN OVER THE ERN DAKOTAS WHILE LIGHT RADAR RETURNS OVER
WRN MN WERE DIMINISHING AS THEY MOVED INTO DRIER AIR TO THE EAST.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 459 AM EDT FRI MAY 11 2012
MODELS HAVE TRENDED SLIGHTLY SLOWER WITH THE MOVEMENT OF THE FRONT
WITH THE NAM AND REGIONAL GEM BRINGING INTO THE WEST BTWN 18Z-21Z
AND THROUGH CNTRL UPPER MI BTWN 00Z-03Z. THE STRONGEST 800-600 MB
FGEN AND FORCING WITH THE RIGHT ENTRANCE OF THE 250 MB JET IS
EXPECTED TO SLIDE FROM MN NE INTO NW ONTARIO...REMAINING TO THE NW
OF THE CWA. INITIAL PCPN CHANCES ARE EXPECTED WITH LOW LEVEL CONV
ALONG THE FRONT DURING THE LATE AFTERNOON. ALTHOUGH DEWPOINTS SHOULD
EVENTUALLY CLIMB INTO THE MID AND UPPER 40S OVER NW WI INTO SW UPPER
MI...ONLY MODEST MLCAPE VALUES NEAR 400 J/KG WILL BE AVBL INTO THE
SOUTHERN PORTION OF THE CWA. WITH ONLY LIMITED INSTABILITY AND LACK
OF STRONGER DYNAMICS...KEPT POPS IN THE CHANCE/SCT RANGE. ALTHOUGH
THERE MAY STILL BE A PERIOD OF POST-FRONTAL FGEN SUPPORTED PCPN
LATER IN THE EVENING...PER REGIONAL GEM AND LCL HIGH RES WRF/ARW...
ESPECIALLY OVER THE NW HALF...EXPECT RAIN TO END BY AROUND 06Z.
SUNSHINE/MIXING INTO THE EARLY AFTERNON SHOULD HELP TEMPS CLIMB INTO
THE MID 70S OVER THE WEST HALF OF THE CWA WITH COOLER READINGS ONLY
IN THE UPPER 50S NEAR LAKE MICHIGAN. WITH MOISTURE ARRIVING...MAINLY
LATE IN THE DAY...RH VALUES COULD DROP AOB 30 PCT OVER THE INLAND
EAST HALF.
A PLEASANT DAY WITH ABUNDANT SUN WILL PREVAIL SATURDAY. COOLER AIR
INTO THE REGION 850 MB TEMPS IN THE 3C-5C RANGE WILL STILL ALLOW
TEMPS TO CLIMB ABOVE SEASONAL AVERAGES INTO THE MID 60S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 452 PM EDT THU MAY 10 2012
SHRA WILL END W TO E FRI NIGHT AS SHORTWAVE/COLD FRONT MAKE STEADY
EASTWARD PROGRESS AND RDG BUILDS IN FROM THE WEST.
COLD FRONT WILL BE EAST OF THE CWA BY 12Z SAT SO HAVE REMOVED POPS
AND PCPN FROM SAT FCST. VERY DRY AIRMASS ASSOC WITH SFC RDG WILL
THEN BUILD OVER THE AREA ON SAT AND CONTINUE INTO SUN LEADING TO LOW
MIN RH/S AND ELEVATED FIRE WEATHER CONCERNS OVER THE WEEKEND. THE
DRY AIR WILL RESULT IN MOSTLY SUNNY SKIES OVER THE WEEKEND AND DEEP
DAYTIME MIXING TO H775 AND POSSIBLY H750. EXPECT DEWPOINT VALUES TO
FALL THROUGH THE AFTN ON SAT AND SUN AS DRIER AIR MIXES TO THE
SFC...ESPECIALLY OVER THE WRN HALF OF THE CWA. MODEL ML DEWPOINTS
ARE IN THE MID TEENS TO LOWER 20S OVER THE WEST ON SAT AND IN THE
MID 20S ON SUNDAY WHILE DEWPOINTS DROP INTO LOWER 30S BOTH DAYS
EAST...SO HAVE CONTINUED THE DOWNWARD TREND IN DEW POINTS FOR GRIDS
OVER BOTH DAYS. THE COMBINATION OF LOWERING DEW POINTS AND HIGH
TEMPS REACHING INTO THE MID 60S AWAY FROM LAKE SUPERIOR WILL PRODUCE
RH VALUES ON SAT BTWN 20-25 PERCENT AND PERHAPS EVEN THE UPPER TEENS
WEST. WITH NW WINDS OF 10-15 MPH THERE COULD BE SOME FIRE WX
CONCERNS...BUT HOPEFULLY THE 0.1 INCH OF RAIN ON FRI NIGHT WILL HELP
LIMIT THEM. FIRE WX CONCERNS WILL CONTINUE ON SUNDAY AS THE
COMBINATION OF HIGH TEMPS IN THE UPPER 60S AND LOWER 70S AND DEW
POINTS LOWERING TO MID 20S COULD DRIVE RH/S AGAIN INTO THE 20-25 PCT
RANGE AND MAYBE EVEN UPPER TEENS AT SOME WRN LOCATIONS.
SHORTWAVE ASSOC WITH THE UPPER LOW NEAR HUDSON BAY LOOKS TO STAY
GENERALLY WELL NORTH OF THE FCST AREA ON SUNDAY AND SUNDAY NIGHT PER
MODEL CONSENSUS SO WILL GO WITH DRY FCST FOR THIS TIME FRAME.
MODELS DIFFER ON TIMING OF WEAK SHORTWAVE/S MOVING THROUGH UPPER
GREAT LAKES IN NW FLOW FOR TUE THROUGH THU TIME FRAME. CONFIDENCE
FOR MEASURABLE PCPN IS LOW AT THIS POINT SO HAVE NO MORE THAN SLIGHT
CHC POPS IN FCST FOR TUE NIGHT INTO THU.
TEMPS SHOULD BE AT OR ABOVE NORMAL THROUGH THE EARLY PART OF NEXT
WEEK WITH A TEMPORARY COOL DOWN BY TUE/WED AND THEN WARMING UP ABV
NORMAL FOR THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 120 AM EDT FRI MAY 11 2012
EXPECT DRY HI PRES OVER THE LOWER GREAT LKS TO BRING VFR CONDITIONS
TO ALL 3 SITES THRU THIS MRNG. A GUSTY S WIND BTWN THIS DEPARTING HI
AND AN APRCHG COLD FNT WL DVLP AFTER SUNRISE WITH SOME DAYTIME
HEATING/MIXING...ESPECIALLY AT THE MORE EXPOSED IWD/SAW LOCATIONS.
BUT LINGERING DRYNESS WL MAINTAIN VFR CONDITIONS. EXPECT A SHARP
WSHFT FOLLOWING THE AFTN FROPA AT CMX/IWD...AND SOME -SHRA/A PERIOD
OF MVFR CONDITIONS ARE LIKELY AT THESE 2 SITES AFTER THE FROPA WITH
UPSLOPE WNW FLOW. THE MORE EXPOSED CMX LOCATION WL SEE GUSTY WNW
WINDS FOLLOWING THE FROPA AS WELL. AT SAW...THE FROPA/-SHRA WL NOT
OCCUR UNTIL SHORTLY AFTER 12/00Z...BUT VFR CONDITIONS SHOULD PREVAIL
THERE WITH DOWNSLOPE FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 452 PM EDT THU MAY 10 2012
HIGH PRESSURE WILL REMAIN OVR MOST OF LK SUPERIOR TONIGHT LEADING TO
LIGHT WINDS. A COLD FRONT APPROACHING FROM THE NORTHERN PLAINS WILL
CAUSE WINDS TO BECOME SOUTHERLY LATE TONIGHT AND FRIDAY...BUT THE
MARINE LAYER SHOULD KEEP WINDS MOSTLY BELOW 15KTS. WINDS WILL SHIFT
TO THE NW BEHIND THE FRONT ON FRIDAY NIGHT AND THEN REMAIN OUT OF
THE WEST THROUGH THE WEEKEND. MOST AREAS SHOULD SEE WINDS STAY BELOW
20KTS DURING THE WEEKEND. WINDS SHOULD REMAIN LESS THAN 20 KTS INTO
MIDDLE PART OF NEXT WEEK AS HIGH PRESSURE IS OVER THE LK SUPERIOR
REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
400 AM CDT FRI MAY 11 2012
.DISCUSSION...
A COLD FRONT EXTENDS FROM NEAR AN INTERNATIONAL FALLS TO SIOUX
FALLS LINE EARLY THIS MORNING. THE FRONT IS MOVING EAST NEAR 20
KNOTS AND WILL BE MOVING ACROSS THE TWIN CITIES BETWEEN 14Z AND 16Z
AND REACH A LADYSMITH TO EAU CLAIRE LINE AROUND 19Z. LOW CONFIDENCE
FORECAST ON PRECIPITATION CHANCES AHEAD OF THE FRONT THIS MORNING.
ALTHOUGH ELEVATED INSTABILITY EXISTS...LITTLE IN THE WAY OF
PRECIPITATION HAS DEVELOPED SO FAR...CONTRARY TO SOME OF THE WRF
FORECASTS. MOST OF THE SHOWERS AND THUNDERSTORMS LAG THE FRONT BY
A CONSIDERABLE DISTANCE. THIS LINES UP WELL WITH THE MID LEVEL
FRONTOGENESIS AND A STRENGTHENING RIGHT ENTRANCE REGION OF THE
UPPER JET OVER NORTH DAKOTA. AS THESE FEATURES MOVE EAST-NORTHEAST
THIS MORNING...THIS WOULD FAVOR AREAS OF WEST CENTRAL INTO
NORTHEAST MINNESOTA AS HAVING THE BEST CHANCES FOR PRECIPITATION TODAY.
IN ADDITION...NEAR ADVISORY CRITERIA WINDS WILL OCCUR THIS
MORNING ACROSS WEST CENTRAL INTO SOUTH CENTRAL MINNESOTA AS A
TIGHT PRESSURE GRADIENT EXISTS BEHIND THE FRONT. THE BEST PRESSURE
RISES ARE DIVING SOUTHEAST TOWARDS KFSD WITH THE ISALLOBARIC
GRADIENT WEAKENING TO OUR WEST. HAVE INDICATED 25-28 MPH SUSTAINED
WINDS THROUGH 15Z FOR THE AFOREMENTIONED AREAS THEN DIMINISHING
SOME THEREAFTER. A NON DIURNAL TEMPERATURE REMAINS IN PLACE TODAY.
THE MID LEVEL FRONTOGENESIS WILL BE OVER EASTERN AND SOUTHERN AREAS
OF THE FA EARLY TONIGHT. PRETTY GOOD AGREEMENT BETWEEN SOLUTIONS
THAT A NARROW BAND OF LIGHT RAIN OR SPRINKLES WILL OCCUR FOR A FEW
HOURS FROM SOUTH CENTRAL MN THROUGH THE TWIN CITIES AND INTO WEST
CENTRAL WISCONSIN. THESE AREAS MIGHT END UP WITH MORE RAIN THIS
EVENING THAN WHAT OCCURS TODAY.
SATURDAY AND SUNDAY WILL BE FINE WEATHER DAYS WITH HIGH PRESSURE
STRETCHED EAST-WEST ACROSS THE UPPER MISSISSIPPI VALLEY. USED MIX
DOWN FOR PART OF THE DEW POINT FORECAST FOR SATURDAY AFTERNOON.
THIS RESULTED IN DEW POINTS DROPPING INTO THE 20S WITH MINIMUM RH
VALUES REACHING NEARLY 20 PERCENT. HIGHS A FEW DEGREES WARMER NOW
WITH MIDDLE TO UPPER 60S ON SATURDAY AND UPPER 60S TO LOWER 70S ON
SUNDAY.
MUCH OF NEXT WEEK STILL LOOKS DRY ALONG WITH HIGHS ABOVE NORMAL.
FORECAST HIGHS RIGHT NOW FOR MONDAY THROUGH THURSDAY ARE MAINLY IN
THE 75 TO 80 DEGREE RANGE. A WEAK WAVE REMAINS NORTHEAST OF THE
REGION ON TUESDAY. ANOTHER WAVE WILL MOVE IN LATE THURSDAY OR
FRIDAY BUT MOISTURE AND FORCING ARE NOT TOO IMPRESSIVE AT THIS
TIME...SO THE IDEA WAS TO DROP THE 15-20 POPS FOR THURSDAY.
&&
.AVIATION... /06Z TAF ISSUANCE/
MAIN WEATHER FEATURE THIS PERIOD WILL BE THE PASSAGE OF A STRONG
COLD FRONT...WHICH AT 5Z...STRETCHED FROM NEAR ROSEAU SW TO NEAR
YANKTON. AWIPS TIMING TOOL BRINGS IT TO AXN AROUND 7Z AND STC/RWF
9Z...THIS IS A BIT QUICKER THAN LAMP GUIDANCE...SO HAVE WIND
SHIFTS AT AIRPORTS ABOUT AN HOUR OR TWO EARLIER THAN THE LAMP.
VERY DRY AIRMASS OUT AHEAD OF THE FRONT HAS KEPT MOST PRECIP BACK
ON THE COLD ADVECTION SIDE OF THE FRONT...BUT EVEN THAT IS PRETTY
SPARSE ONCE YOU GO SOUTH OF NODAK. IS A CLUSTER OF SHOWERS NEAR
ABR THAT THE RUC TAKES TOWARD AXN/STC...BUT AFTER THAT...SHOWER
ACTIVITY IS LOOKING PRETTY SPARSE BASED ON LATEST HRRR AND NAM
REFLECTIVITY FORECASTS...SO HAVE NO MORE THAN VCSH AT ALL OTHER
TERMINALS. AT 18Z...INSTABILITY SPIKES OVER TOWARD EAU...SO THERE
IS A THREAT FOR SHRA/TSRA THERE BETWEEN 18Z AND 21Z. HOWEVER...DRY
AND CAPPED ATMO AHEAD/ALONG THE FRONT SHOULD LIMIT TSRA
COVERAGE...SO REMOVED ITS MENTION. AFTER THAT...NAM IN PARTICULAR
IS SHOWING SHRA CHANCES INCREASING TOWARD 00Z ACROSS MN AS RIGHT
ENTRANCE REGION OF EXITING JET AND BAND OF 700-600 MB FGEN MOVE
ACROSS...THIS MAY BE THE BEST CHANCE FOR RWF/MSP TO SEE -SHRA. FOR
CIGS...WILL BE MAINLY VFR...THOUGH THE HRRR IS SHOWING A NARROW
BAND OF MVFR CIGS WORKING THROUGH BEHIND THE FRONT...SO HAVE TEMPO
GROUPS TO ACCOUNT FOR THAT. WINDS WILL ALSO BE PICKING UP OUT OF
THE NW BEHIND THE FRONT. STILL SEE 30/40 KT GUSTS ACROSS THE
DAKOTAS...AND MAY SEE SIMILAR SPEEDS OVER WRN MN IN THE
MORNING...SO BUMPED UP SPEEDS FOR AXN/RWF. THESE WINDS WILL
QUICKLY DIE DOWN TOWARD SUNSET AS THE CLOUDS THIN OUT FROM WEST
TO EAST.
KMSP...CONTINUED TREND OF 9Z TAF AMD OF ONLY MENTIONING VCSH AS HI
RES MODELS DO NOT PAINT MUCH PRECIP FOR THE AREA THROUGH THE
MORNING. FRONT CURRENTLY OUT RUNNING THE GFSLAMP BY A LITTLE
BIT...AND DO FEEL WE WILL BE SEEING NW WINDS SOONER THAN GUIDANCE
INDICATES. EXTRAPOLATING OFF THE END OF THE HRRR WOULD BRING NW
INTO THE FIELD AT 15Z...SO FAVORED TIMING OF WIND DIRECTION THAT
DIRECTION. STILL LIKE THE IDEA OF ONLY HAVING TEMPO MVFR
CONDITIONS...ESPECIALLY WITH THE LACK OF MVFR CIGS UPSTREAM ACROSS
THE DAKOTAS. WILL HAVE TO WATCH FOR SOME SHOWERS AROUND 00Z AS JET
FORCING MOVES THROUGH...BUT THIS MAY BE NOTHING MORE THAN SOME VIRGA.
/OUTLOOK/
.SAT...VFR. NORTHWEST WINDS 5-10KT.
.SUN...VFR. WESTERLY WINDS 10-15KT.
.MON...VFR. WESTERLY WINDS 10-15KT.
.TUE...VFR. NORTHWEST WINDS 15-20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1216 AM CDT FRI MAY 11 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
ONLY FORECAST CONCERN DURING THE NEXT SIX DAYS IS PRECIPITATION
CHANCES LATE TONIGHT THROUGH FRIDAY EVENING. THE LATEST SHORT TERM
MODELS HAVE BEEN CONSISTENT WITH THE FRONTAL POSITIONS AND
PRECIPITATION DEVELOPMENT OVER THE UPPER MIDWEST.
SATELLITE IMAGERY OFF THE IR LOOP DEPICTED SHORTWAVE TROUGH OVER THE
NORTHERN PLAINS WITH WELL DEFINED DRYING BEHIND OVER THE NORTHERN
ROCKIES. MOST OF THE SHOWER/TSTM ACTIVITY WAS POST FRONTAL. ON
THIS FORECAST ISSUANCE...ATTEMPTED TO RE-DEFINED POPS/WEATHER
GRIDS TO ADJUST MORE TO THE BEGINNING/ENDING OF THE PRECIPITATION.
FORECAST QPF EXPECTED TO GENERALLY LESS ONE QUARTER OF AN INCH.
AFTERWARDS...DRY NORTHWEST AIRFLOW WILL ENSUE ACROSS THE UPPER
MIDWEST WITH TEMPERATURES MODERATING INTO THE 70S TO AROUND 80
DEGREES BY SUNDAY EVENING.
SURFACE HIGH PRESSURE WILL REMAIN ENTRENCHED OVER THE MIDWEST
THROUGH FRIDAY OF NEXT WEEK.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN WEATHER FEATURE THIS PERIOD WILL BE THE PASSAGE OF A STRONG
COLD FRONT...WHICH AT 5Z...STRETCHED FROM NEAR ROSEAU SW TO NEAR
YANKTON. AWIPS TIMING TOOL BRINGS IT TO AXN AROUND 7Z AND STC/RWF
9Z...THIS IS A BIT QUICKER THAN LAMP GUIDANCE...SO HAVE WIND
SHIFTS AT AIRPORTS ABOUT AN HOUR OR TWO EARLIER THAN THE LAMP.
VERY DRY AIRMASS OUT AHEAD OF THE FRONT HAS KEPT MOST PRECIP BACK
ON THE COLD ADVECTION SIDE OF THE FRONT...BUT EVEN THAT IS PRETTY
SPARSE ONCE YOU GO SOUTH OF NODAK. IS A CLUSTER OF SHOWERS NEAR
ABR THAT THE RUC TAKES TOWARD AXN/STC...BUT AFTER THAT...SHOWER
ACTIVITY IS LOOKING PRETTY SPARSE BASED ON LATEST HRRR AND NAM
REFLECTIVITY FORECASTS...SO HAVE NO MORE THAN VCSH AT ALL OTHER
TERMINALS. AT 18Z...INSTABILITY SPIKES OVER TOWARD EAU...SO THERE
IS A THREAT FOR SHRA/TSRA THERE BETWEEN 18Z AND 21Z. HOWEVER...DRY
AND CAPPED ATMO AHEAD/ALONG THE FRONT SHOULD LIMIT TSRA
COVERAGE...SO REMOVED ITS MENTION. AFTER THAT...NAM IN PARTICULAR
IS SHOWING SHRA CHANCES INCREASING TOWARD 00Z ACROSS MN AS RIGHT
ENTRANCE REGION OF EXITING JET AND BAND OF 700-600 MB FGEN MOVE
ACROSS...THIS MAY BE THE BEST CHANCE FOR RWF/MSP TO SEE -SHRA. FOR
CIGS...WILL BE MAINLY VFR...THOUGH THE HRRR IS SHOWING A NARROW
BAND OF MVFR CIGS WORKING THROUGH BEHIND THE FRONT...SO HAVE TEMPO
GROUPS TO ACCOUNT FOR THAT. WINDS WILL ALSO BE PICKING UP OUT OF
THE NW BEHIND THE FRONT. STILL SEE 30/40 KT GUSTS ACROSS THE
DAKOTAS...AND MAY SEE SIMILAR SPEEDS OVER WRN MN IN THE
MORNING...SO BUMPED UP SPEEDS FOR AXN/RWF. THESE WINDS WILL
QUICKLY DIE DOWN TOWARD SUNSET AS THE CLOUDS THIN OUT FROM WEST
TO EAST.
KMSP...CONTINUED TREND OF 9Z TAF AMD OF ONLY MENTIONING VCSH AS HI
RES MODELS DO NOT PAINT MUCH PRECIP FOR THE AREA THROUGH THE
MORNING. FRONT CURRENTLY OUT RUNNING THE GFSLAMP BY A LITTLE
BIT...AND DO FEEL WE WILL BE SEEING NW WINDS SOONER THAN GUIDANCE
INDICATES. EXTRAPOLATING OFF THE END OF THE HRRR WOULD BRING NW
INTO THE FIELD AT 15Z...SO FAVORED TIMING OF WIND DIRECTION THAT
DIRECTION. STILL LIKE THE IDEA OF ONLY HAVING TEMPO MVFR
CONDITIONS...ESPECIALLY WITH THE LACK OF MVFR CIGS UPSTREAM ACROSS
THE DAKOTAS. WILL HAVE TO WATCH FOR SOME SHOWERS AROUND 00Z AS JET
FORCING MOVES THROUGH...BUT THIS MAY BE NOTHING MORE THAN SOME VIRGA.
/OUTLOOK/
.SAT...VFR. NORTHWEST WINDS 5-10KT.
.SUN...VFR. WESTERLY WINDS 10-15KT.
.MON...VFR. WESTERLY WINDS 10-15KT.
.TUE...VFR. NORTHWEST WINDS 15-20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JVM/MPG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
145 AM EDT FRI MAY 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST TONIGHT THROUGH
SATURDAY. THE HIGH WILL SLIDE OFFSHORE SUNDAY AND SUNDAY NIGHT. A
COLD FRONT WILL SLOWLY APPROACH FROM THE WEST MONDAY THEN STALL
NEAR THE REGION TUESDAY INTO WEDNESDAY. THE FRONT WILL SLOWLY
DRIFT OFFSHORE THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
EXCELLENT RADIATIONAL COOLING CONDITIONS THIS MORNING WITH MOCLR
SKIES AND CALM/ LIGHT WINDS. HAVE DROPPED LOWS A FEW DEGS TOTHE
UPPER 40S INLAND WITH 50S AT THE COAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/...
AS OF 230 PM THURSDAY...MAINLY SUNNY SKIES EXPECTED AS HIGH PRES
BUILDS IN FROM THE NW WITH VERY DRY AIRMASS OVER THE AREA.
THICKNESSES SUPPORT TEMPS SIMILAR TO TODAY WITH INLAND SITES CPL
DGRS EITHER SIDE OF 75 AND BEACHES AROUND 70.
&&
.LONG TERM /TONIGHT THROUGH THURSDAY/...
AS OF 230 PM THU...SFC HIGH PRESSURE WILL CONTINUE TO BUILD OVER
THE AREA THROUGH SAT NIGHT...BEFORE MOVING OFFSHORE SUNDAY.
PREDOMINATE DRY AND SEASONABLE CONDITIONS WILL CONTINUE THROUGH
THE WEEKEND. COOL CONDITIONS EXPECTED FRI NIGHT INTO SAT MORNING
WITH GOOD RADIATIONAL COOLING SETUP...WITH MOSTLY CLEAR SKIES AND
LIGHT WINDS. CONTINUED WITH LOWS IN THE MID TO UPPER 40S
INLAND...AND LOWER TO MID 50S ALONG THE COAST...WITH SOME OF THE
TYPICALLY COOLER SPOTS POSSIBLY MAKING IT DOWN INTO THE LOWER 40S
INLAND. STILL SOME UNCERTAINTY HEADING INTO THE BEGINNING AND
MIDDLE OF NEXT WEEK...BUT OVERALL LOOKS LIKE IT COULD BE WET AT
TIMES...AS FRONTAL SYSTEM IN THE OH VALLEY MON MOVES EASTWARD
THROUGH WED POSSIBLY STALLING ALONG THE SE COAST. WILL CONTINUE
CHANCE POPS THROUGH MID WEEK.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /06Z FRIDAY THROUGH 06Z SATURDAY/..
VFR PREVAILING THROUGH TAF PERIOD BUT WUDNT BE SUPRISED IF SOME
SHALLOW GROUND FOG DEVELOPS BEFORE SUNRISE. EVEN IF IT DOES
DEVELOP IT WILL HAVE LITTLE OPERATIONAL IMPACT. BRIEF SURGE OF NW
WINDS EXPECTED FRI MORNING BUT SPEEDS LESS THAN 15 KT.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM THU...PREDOMINATE VFR CONDITIONS EXPECTED THROUGH THE
PERIOD. SCT SHOWERS AND THUNDERSTORMS EXPECTED MON THROUGH TUE
WITH PERIOD OF SUB-VFR CONDITIONS POSSIBLE.
&&
.MARINE...
SHORT TERM /THROUGH FRIDAY/...
WEAK HIGH PRES OVER AREA RESULTING IN VARYING WIND DIRECTIONS
WITH SPEEDS MAINLY BELOW 10 KT. LATEST HRRR RUN HAS BEST HANDLE ON
THIS AND FOLLOWED IT FOR OVERNIGHT UPDATE. BASICALLY HAVE CURRENT
TREND CONTINUING OVERNIGHT...THEN BECOMING N 10-15 KT LATE WITH
BRIEF CAA SURGE AFTER SHRT WV PASSAGE. NO CHANGE TO SEAS...MAINLY
2-4 FT.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM THU...HIGH PRESSURE WILL CONTINUE OVER THE WATERS
THROUGH SAT NIGHT...THEN MOVE OFFSHORE SUN. VARIABLE WINDS FRI
NIGHT INTO SAT AOB 10KT AND SEAS 2-3FT. SAT NIGHT THROUGH MON
NIGHT...EXPECT PREDOMINATE S/SE WINDS AOB 15KT AND SEAS 2-4FT WITH
HIGH PRESSURE OFFSHORE. EARLY TO MID WEEK STILL A LITTLE BIT OF
UNCERTAINTY WITH LITTLE RUN TO RUN MODEL CONSISTENCY...WILL
CONTINUE TO TREND WITH HPC AND PREVIOUS FORECAST...KEEPING
PREDOMINATE S/SE WINDS AND SEAS 2-5FT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RF
NEAR TERM...BTC/RF
SHORT TERM...RF
LONG TERM...CQD
AVIATION...BTC/RF/CQD
MARINE...RF/CQD
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1250 PM CDT FRI MAY 11 2012
.UPDATE...
BASED ON RADAR TRENDS AND LATEST RUC DATA...I ADJUSTED POP AND
WEATHER GRIDS FOR THE REMAINDER OF TODAY. SHOWERS WILL BE THE MAIN
WEATHER ELEMENT WITH ISOLATED THUNDERSTORMS. LATEST ZONE PRODUCT
REFLECTS THESE CHANGES.
HUBER
&&
.DISCUSSION...
LOOK FOR STRATUS TO RETURN TO WEST CENTRAL TEXAS LATE TONIGHT. SEE
AVIATION BELOW FOR DETAILS.
&&
.AVIATION...
LOOK FOR CONTINUED CHANGES TO FLIGHT WEATHER CONDITIONS ACROSS
WEST CENTRAL TEXAS FOR THE NEXT 24 HOURS. LATEST WSR-88D AND
SATELLITE DATA INDICATE THE UPPER-LEVEL LOW IS CURRENTLY CENTERED
NEAR OUR WESTERN BIG COUNTRY COUNTIES. SOUTH OF THIS
CENTER...SUBSIDENCE AND SLIGHTLY DRIER AIR WILL LIKELY LIMIT
THUNDERSTORM DEVELOPMENT THIS AFTERNOON. IF THUNDERSTORMS DEVELOP
THIS AFTERNOON...I BELIEVE THEY WILL BE MAINLY ISOLATED. AS THE
UPPER LOW TRACKS FARTHER EAST THIS AFTERNOON...THE POTENTIAL FOR
CONTINUED THUNDERSTORMS WILL DIMINISH. THUS...I DID NOT INCLUDE
ANY THUNDER ELEMENTS IN ANY OF THE TERMINALS FOR 00Z AND BEYOND.
AS THE LOW TRACKS FARTHER EAST OVERNIGHT...MODELS INDICATE STRATUS
WILL MOVE INTO WEST CENTRAL TEXAS FROM THE NORTH...BEHIND THE
SURFACE LOW. THE NAM...AS USUAL...IS MORE PESSIMISTIC AND PRESENTS
LOWER CEILING HEIGHTS THAN THE GFS. I DECIDED TO GO WITH MVFR
CEILINGS AROUND 1500 FEET ABOVE GROUND LEVEL BY 12Z TOMORROW
MORNING FOR ALL FIVE TERMINALS. HOWEVER...I DO NOT EXPECT THESE
MVFR CEILINGS TO DEVELOP UNTIL LATE IN THE FORECAST PERIOD.
SO...MY 1500 FEET REPRESENTS A LIKELY AVERAGE CEILING HEIGHT
ACROSS WEST CENTRAL TEXAS. BY 15Z...PLAN FOR VFR CEILINGS TO AGAIN
DOMINATE WEST CENTRAL TEXAS.
HUBER
&&
.PREV DISCUSSION... /ISSUED 640 AM CDT FRI MAY 11 2012/
DISCUSSION...
AVIATION DISCUSSION FOLLOWS.
AVIATION...
FOG HAS RESTRICTED VISIBILITIES AT KABI...KBBD...AND KJCT THIS MORNING.
VISIBILITIES SHOULD IMPROVE AROUND 15Z TO MVFR. THE REMAINING TAF
SITES ARE VFR. EXPECT TSTORMS TO DEVELOP SHORTLY AFTER 18Z WITH
DAYTIME HEATING BENEATH THE UPPER LOW THAT WILL BE TRAVERSING THE
REGION TODAY. THE STRONGEST STORM MAY PRODUCE GUSTY WINDS...LARGE
HAIL...AND LIGHTNING. TSTORMS SHOULD DISSIPATE BY 00Z.
PREV DISCUSSION... /ISSUED 324 AM CDT FRI MAY 11 2012/
SHORT TERM...
PATCHY DENSE FOG FORMED AT JUNCTION EARLY THIS MORNING. BUT THIS FOG
SHOULD BURN OFF BY MID MORNING. PLAN TO COVER WITH NOWCASTS.
ISOLATED SHOWERS HAVE BEGUN TO FORM ACROSS WC TX.
THE UPPER LOW WAS LOCATED JUST NORTH OF WINK ALONG THE TX/NM
BORDER. MEANWHILE...A SHORTWAVE WAS DIVING SOUTHEAST INTO THE
SOUTHERN ROCKIES AND SHOULD HELP TO SWEEP THE UPPER LOW EAST AND
NORTHEAST ACROSS WC TX TODAY. THE ADVANCING UPPER LOW WILL SPREAD
COLDER AIR ALOFT ACROSS THE REGION RESULTING IN AFTERNOON SHOWERS
AND THUNDERSTORMS AS THE ATMOSPHERE DESTABILIZES. THE AMOUNT OF
SURFACE HEATING WILL AFFECT THE AMOUNT OF INSTABILITY. LATEST MODEL
SOUNDINGS SHOW CAPES BELOW 1000 J/KG. HOWEVER...IN AREAS OF GOOD
SURFACE HEATING...THE STRONGEST ISOLATED THUNDERSTORM COULD BECOME
SEVERE AND PRODUCE LARGE HAIL BECAUSE OF THE COLD AIR ALOFT. WITH
THE GROUND ALREADY SATURATED FROM YESTERDAY`S RAINFALL...LOCALIZED
FLASH FLOODING WILL ALSO BE POSSIBLE. LOWERED POPS FOR THIS EVENING
AND ENDED POPS AFTER 06Z
LONG TERM...
A FEW LINGERING SHOWERS WILL BE POSSIBLE SATURDAY MORNING...
MAINLY ACROSS THE EASTERN BIG COUNTRY AND HEARTLAND. AS THE UPPER
LOW MOVES EAST OF THE AREA IT WILL WEAKEN WITH THE RESULTANT
UPPER TROUGH MOVING OVER THE LOWER MISSISSIPPI VALLEY BY LATE
SATURDAY. A DEVELOPING UPPER TROUGH OVER THE FOUR CORNERS AREA
LATE SUNDAY WILL CLOSE OFF OVER THE PANHANDLE BY TUESDAY MORNING
BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
FORECAST AREA BEGINNING SUNDAY EVENING THROUGH TUESDAY NIGHT...A
FEW STRONG STORMS COULD APPROACH SEVERE LEVELS WITH LOCALLY HEAVY
RAINFALL A POSSIBILITY. THIS STORM SYSTEM WILL KEEP AFTERNOON
HIGHS MOSTLY IN THE 70S THROUGH TUESDAY. AS THIS SYSTEM DEPARTS
THE AREA...AFTERNOON HIGHS WILL AGAIN WARM INTO THE 80S THROUGH
THE END OF THE EXTENDED WITH ENSUING DRY WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 75 57 78 58 / 40 20 10 10 20
SAN ANGELO 57 78 57 81 58 / 10 10 10 10 20
JUNCTION 55 80 56 81 59 / 20 10 10 0 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
255 PM EDT FRI MAY 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL COVER THE REGION THROUGH SATURDAY. BY SUNDAY
THE HIGH MOVES OFFSHORE AND LOW PRESSURE WILL APPROACH FROM LOWER
MISSISSIPPI VALLEY. MONDAY AND TUESDAY A COLD FRONT WILL CROSS
THROUGH THE EASTERN UNITED STATES.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 250 PM EDT FRIDAY...
UPPER RIDGE/SFC HIGH PRESSURE WILL SETTLE OVERHEAD TONIGHT.
EXPECT GOOD RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND
LIGHT WINDS. LOWS WILL RANGE FROM THE UPPER 30S IN THE COLDER VALLEY
TO THE MID 40S IN THE SOUTH.
MOISTURE SLOWLY INCREASES ON SATURDAY AS SURFACE LOW PRESSURE MOVES
INTO THE LOWER MISSISSIPPI VALLEY. WITH POOLING OF MOISTURE AND
UPSLOPE FLOW...ALLOWED FOR SOME LIGHT SHOWERS IN THE SOUTHWEST
MOUNTAINS SATURDAY AFTERNOON. PLAYED HIGH TEMPERATURES SATURDAY
AFTERNOON FROM THE UPPER 60S IN THE MOUNTAINS TO THE MID 70S IN THE
SOUTHEAST.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EDT FRIDAY...
DETERIORATING WEATHER CONDITIONS EXPECTED DURING THE SHORT TERM
PERIOD OF THE FORECAST...AS ENERGY FROM SOUTHERN STREAM LOW ACROSS
TEXAS TODAY MERGES WITH A NORTHERN STREAM WAVE MOVING THROUGH THE
GREAT LAKES.
THE FIRST FORECAST CONCERN IS WHEN PRECIP DEVELOPS. THE GFS MOISTENS
THE AIRMASS QUICKLY...INCREASING PWATS TO OVER AN INCH OVER MUCH OF
THE FORECAST AREA BY SUNDAY MORNING. THE NAM IS MUCH SLOWER...BUT
WAS DISREGARDED. WITH THE LOW LEVEL THETA-E RIDGE SNEAKING UP THE
FAR WESTERN PORTION OF THE FORECAST AREA...COMBINED WITH ISENTROPIC
LIFT...KEPT SMALL POPS ACROSS THE FAR WESTERN PORTION OF THE
FORECAST AREA.
ON SUNDAY...WEAK SHORT WAVES BEGIN TO INVADE THE AREA FROM THE
SOUTHWEST IN A DEEP SOUTHWEST FLOW. MOST OF THE PRECIPITATION
SHOULD REMAIN IN THE WESTERN HALF OF THE FORECAST AREA UNDER THE
THETA-E RIDGE.
PRECIP SHOULD EXPAND EAST OF THE BLUE RIDGE BY LATE SUNDAY NIGHT AND
ESPECIALLY MONDAY AS THE SFC COLD FRONT APPROACHES AND LOW LEVEL
WINDS BACK...INCREASING LOW LEVEL CONVERGENCE. PLUS A BROAD AREA OF
UPPER DIVERGENCE FORMS AS OUR FORECAST AREA FALLS UNDER THE RR QUAD
OF NORTHERN STREAM JET.
THIS SPELLS THE POTENTIAL FOR A HEAVY RAIN EVENT ON MONDAY..AS
PWATS INCREASE TO GREATER THAN 2 STANDARD DEVIATIONS ABOVE NORMAL ON
MONDAY...AND WITH GEFS...AND TO LESSER EXTENT...NAEFS HYDROLOGIC
ENSEMBLES SHOWING A SMALL CHANCE SOME RIVER GAUGE LOCATIONS
EXCEEDING ACTION STAGE. THEREFORE...WILL INTRODUCE A MENTION OF THE
THREAT FOR MINOR FLOODING IN THE HWO.
WITH EXTENSIVE CLOUD COVER AND PRECIP EXPANDING IN
COVERAGE...NARROWED THE DIURNAL RANGE IN TEMPS...INCREASING LOWS AND
REDUCING HIGHS...ESPECIALLY MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM EDT THURSDAY...
AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE EARLY PART OF THE LONG
TERM PERIOD. BOTH THE GFS AND ECMWF PHASE THE SOUTHERN STREAM LOW
CURRENTLY IN TEXAS...WITH A NORTHERN STREAM WAVE MOVING ACROSS THE
GREAT LAKES. THE RESULTS IN A PERSISTENT LONG WAVE TROF ACROSS THE
EASTERN U.S...WITH WAVES OF LOW PRESSURE AT THE SFC RIDING NORTHEAST
ALONG A SLOW MOVING FRONTAL BOUNDARY THROUGH TUESDAY NIGHT AND
POTENTIALLY INTO WEDNESDAY.
THE 00Z ECMWF IS MOST PROGRESSIVE WITH MOVING THE AXIS OF THIS UPPER
TROF TO THE EAST OF OUR AREA WEDNESDAY...WHILE THE 06Z GFS IS MUCH
SLOWER AND DEEPER...WHICH APPEARS TO BE AN OUTLIER WHEN COMPARED TO
ITS ENSEMBLES. A SOLUTION SOMEWHERE BETWEEN IS PROBABLY THE MOST
LIKELY SCENARIO...AS THE ECMWF ENSEMBLE MEAN SUGGESTS. AS A
RESULT...KEPT POPS IN THE FORECAST FOR WEDNESDAY.
LATER THE LONG TERM PERIOD...THE LONG RANGE MODELS DIVERGENCE
CONSIDERABLY ON THE WHAT WILL TRANSPIRE. THE 12Z GFS DEVELOPS A CUT
OFF LOW IN EASTERN NC...WHILE 0Z ECMWF LIFTS THE EASTERN U.S. TROF
WELL AWAY FROM OUR AREA. THE MAJORITY OF THE INDIVIDUAL GFS
ENSEMBLES AGREE WITH THE ECMWF ENSEMBLE MEAN OF KEEPING AN OPEN
UPPER LEVEL TROF OVER THE EASTERN U.S. WITH THE RNK FORECAST AREA
JUST TO THE WEST OF THE UPPER TROF AXIS FROM THE ENSEMBLE
MEANS...WILL KEEP THE FORECAST DRY...BUT CONFIDENCE IS LOW DURING
THIS TIME.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AS OF 140 PM EDT FRIDAY...
GREAT FLYING WEATHER WITH VFR CONDITIONS ARE EXPECTED THROUGH THE
FORECAST PERIOD. HIGH PRESSURE AND A DRY AIR MASS WILL REMAIN OVER
THE REGION THROUGH SATURDAY MORNING. WINDS WILL BE VARIABLE
DIRECTION...ESPECIALLY BY LATE AFTERNOON WITH SPEEDS LESS THAN 10
KNOTS.
SOME MOISTURE RETURN ON SATURDAY WITH ISOLATED SHOWERS POSSIBLE IN
THE SOUTHWEST MOUNTAINS .BY SATURDAY NIGHT THE HIGH MOVES OFFSHORE
AND DEEPER MOISTURE BEGINS TO ADVANCE NORTH ACROSS THE SOUTHERN
APPALACHIANS. PRECIPITATION WILL REACH THE WESTERN CAROLINAS AND
WESTERN VIRGINIA INTO THE OHIO VALLEY. CEILINGS AND VISIBILITIES
MAY DROP TO MVFR VALUES AT BLF AND LWB ON SUNDAY THEN ALSO AT
ROA/BCB/DAN AND LYH ON SUNDAY NIGHT THROUGH TUESDAY AS LOW
PRESSURE AND THE ASSOCIATED PRECIPITATION MOVE EAST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...KK
SHORT TERM...PH
LONG TERM...PH
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1103 PM MDT SAT MAY 12 2012
.AVIATION...
-SHRA WILL AFFECT KCOS AND KPUB TAF SITES THROUGH 08-09Z AS BAND
OF SHOWERS MOVES OFF THE MOUNTAINS AND INTO THE ADJACENT PLAINS.
CIGS/VIS WITH THESE SHOWERS SHOULD STAY IN THE VFR CATEGORY. SOME
CLEARING EXPECTED WITH POTENTIAL FOR MVFR STRATUS AT KCOS AND KPUB
FROM 09Z-15Z. KALS WILL SEE VFR CONDITIONS...WITH ANY POTENTIAL
FOR -SHRA EXPECTED TO BE TOO MINIMAL TO WARRANT MENTION IN THE TAF
AT THIS POINT. WITH RECENT RAINFALL...AND SOME CLEARING...THERE
COULD BE A WINDOW FOR SOME BRIEF MVFR FOG/STRATUS AT THE KALS
TERMINAL TOWARDS MORNING. ANY FOG SHOULD BE FAIRLY SHALLOW AT
KALS...BUT COULD HAVE THE POTENTIAL TO DROP VIS INTO THE IFR
CATEGORY TOWARDS 12Z. THIS WILL CONTINUE TO BE MONITORED THROUGH
THE OVERNIGHT HOURS. UPPER LEVEL SYSTEM WILL CAUSE -TSRA TO DEVELOP
FAIRLY EARLY ACROSS THE MOUNTAINS...AND DRIFT OFF INTO THE
ADJACENT PLAINS SUN AFTERNOON. WILL CARRY EITHER -TSRA OR VCTS AT ALL
THREE TAF SITES AFTER 20-22Z. -KT
&&
.PREV DISCUSSION... /ISSUED 945 PM MDT SAT MAY 12 2012/
UPDATE...
LATEST MODELS ARE BACKING OFF ON THE SOLN OF WIDESPREAD RAINFALL
SPREADING EASTWARD ACROSS THE SOUTHEAST PLAINS DURING THE LATE
EVENING/OVERNIGHT HOURS. NAM12 AND RUC13 DIMINISH AREA OF PCPN
QUICKLY AS IT MOVES OFF THE MTS INTO THE I-25 CORRIDOR OF EL
PASO/PUEBLO COUNTY THROUGH 06-09Z...WITH ALL QPF DONE BY 09Z. 00Z
HRRR RUN IS THE MOST OPTIMISTIC (WETTEST) HIGH RES MODEL FOR THE
I-25 CORRIDOR/ADJACENT PLAINS...WITH FAIRLY WIDESPREAD SHOWERS
MOVING EASTWARD ACROSS EL PASO/PUEBLO/NRN HUERFANO COUNTIES
THROUGH 06Z...HOWEVER IT TOO DOES DWINDLE PCPN QUICKLY AS IT
CONTINUES MOVING SOUTHEAST ACROSS CROWLEY...OTERO...BENT...AND
EASTERN LAS ANIMAS COUNTIES THROUGH 12Z...WITH FAR EASTERN
COUNTIES SEEING LITTLE OR NO RAINFALL OVERNIGHT. ALL THIS IS
LIKELY DUE TO THE SLOWER SOUTHWARD TREND IN THE UPPER LEVEL
SHORTWAVE TO THE NORTHWEST...WITH SYSTEM COMING THROUGH AT NIGHT
WHEN STABILIZATION HAS ALREADY OCCURRED. ISENTROPIC UPGLIDE ON THE
300-305K SFC ALSO LOOKS MUCH WEAKER AS A RESULT OF THIS SLOWER
TIMING...WHICH MEANS LESS FORCING TO CONTINUALLY GENERATE SHOWERS
OVERNIGHT. THUS...HAVE DECREASED POPS ACROSS THE SOUTHEAST
PLAINS. WILL MAINTAIN A SMALL WINDOW FOR LIKELY POPS ACROSS EL
PASO/PUEBLO COUNTIES (THROUGH 06Z FOR EL PASO COUNTY...AND THROUGH
09Z FOR PUEBLO COUNTY AND POINTS TO THE SE) AS THERE MAY BE ENOUGH
FORCING FOR AT LEAST SOME SHOWERS THROUGH THAT PERIOD. -KT
PREV DISCUSSION... /ISSUED 258 PM MDT SAT MAY 12 2012/
SHORT TERM...
(TONIGHT AND SUNDAY)
.ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TONIGHT...A LITTLE
DRIER ON SUNDAY BUT STILL ANOTHER ROUND OF SHOWERS AND STORMS...
WATER VAPOR PICTURES THIS AFTERNOON SHOW A RATHER VIGOROUS SHORTWAVE
DIGGING SOUTHEAST ACROSS NORTHEASTERN UTAH AND SOUTHWESTERN
WYOMING...HEADING INTO NORTHWEST COLORADO. THIS WAVE IS ALREADY
HELPING TO INITIATE CONVECTION IN A BIG WAY OVER ALL OF THE COLORADO
MOUNTAINS. ALTHOUGH MODELS DIFFER ON THE DETAILS OF WHERE AND HOW
MUCH RAIN WILL FALL...THEY ARE ALL IN AGREEMENT ON BRINGING FAIRLY
WIDESPREAD SHOWERS EAST OFF THE MOUNTAINS THIS AFTERNOON...ONTO THE
PLAINS THIS EVENING...AND CONTINUING ACROSS THE FAR EASTERN PLAINS
THROUGH THE OVERNIGHT HOURS. FOR THE MOST PART...THE MAIN WEATHER
TO EXPECT FROM THESE STORMS WILL BE RAIN. ALTHOUGH...AS THE CELLS
FIRST DEVELOP...IN THE PRE-STORM CAPE THAT IS AVAILABLE...THEY MAY
HAVE A BIT MORE UMP...AND DROP SOME HAIL FROM PEA UP TO PENNY SIZE.
ALREADY HAD ONE CASE OF THIS A LITTLE BEFORE 1 PM TODAY FROM A STORM
2 MILES EAST OF SOUTH FORK IN RIO GRANDE COUNTY. THE SPOTTER THERE
REPORTED DIME TO QUARTER SIZE HAIL FROM A CELL THAT DIDN`T LOOK LIKE
MUCH ON RADAR.
SNOW LEVELS TONIGHT WILL PROBABLY NOT BE QUITE AS LOW AS LAST
NIGHT. HIGHER DEWPOINT AIR HAS BEEN ADVECTING INTO THE REGION
TODAY...THUS LOWERING THE POTENTIAL FOR STRONG DIABATIC COOLING
DURING PRECIPITATION. YESTERDAY AT THIS TIME...DEWPOINTS AROUND THE
AREA WERE GENERALLY IN THE LOWER TO MIDDLE 30S. THIS AFTERNOON...
THEY HAVE WARMED MOSTLY TO THE UPPER 30S AND LOWER 40S...AND THEY
ARE FORECAST TO CONTINUE RISING A BIT MORE. SO...WET BULB ZERO
TEMPERATURES HAVE GONE UP AND...CONSEQUENTLY...SO HAVE THE SNOW
LEVELS. FOR TONIGHT...LOOKS LIKE ABOUT 9000 FEET FOR ACCUMULATING
SNOW POTENTIAL. HOWEVER...COULD SEE SOME WET SNOW DOWN TO ABOUT
8000 FEET DURING THE HEAVIER PRECIPITATION PERIODS...WITH LITTLE OR
NO SNOW ACCUMULATION EXPECTED.
FOR SUNDAY...UPPER LOW IS STILL MAKING ITS WAY SOUTH ACROSS THE
AREA. SO...WE WILL HAVE YET ANOTHER COOL AND UNSETTLED DAY BEFORE
THE PATTERN CHANGES. OVERALL...THE AIRMASS OVER SOUTHERN COLORADO
TOMORROW LOOKS A LITTLE DRIER...SO GENERALLY DO NOT THINK WE WILL
SEE AS HEAVY OF PRECIPITATION AMOUNTS AS THE PAST COUPLE OF DAYS.
HOWEVER...SHOULD STILL SEE FAIRLY GOOD COVERAGE OF LIGHT SHOWERS
ACROSS THE AREA. THE PEAK PERIOD FOR PRECIPITATION TOMORROW SHOULD
AGAIN ALIGN FAIRLY WELL WITH PEAK DIURNAL HEATING...SO THE BEST
CHANCE FOR SHOWERS AND THUNDERSTORMS SHOULD AGAIN BE DURING THE
AFTERNOON INTO THE EVENING HOURS. THIS TIME...THE PRECIPITATION
WILL PROBABLY FOCUS MORE ON LOCATIONS FROM THE I-25 CORRIDOR
WESTWARD...AND ALSO ALONG THE RATON MESA. THE PLAINS MAY NOT SEE
SO MUCH. LW
LONG TERM...
(SUNDAY NIGHT THROUGH NEXT SATURDAY)
FORECAST FOR NEXT WEEK LOOKS RELATIVELY QUIET AND UNEVENTFUL. THE
JET STREAM REMAINS WELL TO THE N...AND ASIDE FROM A FEW WEAK SHORT
WAVES TO CONTEND WITH...THE PATTERN LOOKS DRY AND WARM.
SHOWERS AND STORMS SHOULD WRAP UP FAIRLY QUICKLY SUN NIGHT AS THE
CURRENT UPPER DISTURBANCE PASSES INTO THE TX PANHANDLE. JUST SOME
LINGERING CONVECTION INTO MON...MAINLY ALONG OUR SRN BORDER WITH NM.
AN UPPR RIDGE BUILDS FROM MON INTO TUE...AND THIS WILL USHER IN
WARMER WEATHER WITH GENERALLY DRY CONDITIONS. HIGH TEMPS OVR THE
PLAINS LIKELY TO BE IN THE MID TO POSSIBLY UPPR 80S FOR THE LATTER
HALF OF THE WEEK...AS H7 TEMPS BUILD TO THE 10-15 DEG C RANGE.
ANOTHER WEAK DISTURBANCE MOVES QUICKLY THRU CO ON WED. DEWPOINTS E
OF A DIFFUSE DRY LINE SHOULD BE JUST HIGH ENOUGH FOR SOME STRONG
CONVECTION BY LATE AFTERNOON TO EARLY EVE...ESPECIALLY NR THE KS
BORDER. MID LEVEL FLOW STILL TOO WEAK TO PRODUCE ANY SIGNIFICANT
CHANCE OF SVR WX. MAIN THREAT WILL PROBABLY BE HEAVY RAIN AND
PERHAPS SMALL HAIL...BUT STILL SOME UNCERTAINTY ON THE STRENGTH OF
THIS SHORT WAVE.
AFTER THAT...MORE UPPR RIDGING BRINGS BACK DRY WX ALONG WITH
ABOVE AVERAGE TEMPERATURES FROM THU INTO NEXT WEEKEND. 44
AVIATION...
UPPER DISTURBANCE VISIBLE IN SATELLITE PICTURES WILL TRACK
SOUTHEAST ACROSS COLORADO TONIGHT. DISTURBANCE WILL RESULT IN
CONTINUED WIDESPREAD IFR/MVFR CIGS ACROSS THE PLAINS. MOUNTAINS
AND VALLEYS ARE GENERALLY ABOVE THE LOW STRATUS DECK ACROSS THE
PLAINS...SO IFR/MVFR CIGS WILL BE MORE TRANSIENT...TIED TO CONVECTIVE
SHOWERS MOVING THROUGH. UPPER DISTURBANCE WILL BRING ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS ONTO THE
PLAIN LATE THIS AFTERNOON. THESE SHOWERS AND STORMS WILL TRANSITION
EASTWARD ACROSS THE PLAINS THIS EVENING...PROGRESSING ACROSS THE FAR
EASTERN PLAINS THROUGH THE OVERNIGHT HOURS. ACCUMULATING SNOW
POTENTIAL DOWN TO ABOUT 9000 FEET. HOWEVER...SOME WET SNOW WITH
LITTLE SNOW ACCUMULATION POSSIBLE DOWN TO ABOUT 8000 FEET. UPPER LOW
WILL STILL BE TRAVERSING SOUTH ACROSS THE REGION ON SUNDAY. NO
REAL IMPROVEMENT EXPECTED IN WEATHER CONDITIONS UNTIL LATE
SUNDAY NIGHT AND MONDAY...WHEN EVERYTHING SHIFTS SOUTH INTO NEW
MEXICO AND HIGH PRESSURE REBUILDS OVER COLORADO. LW
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MDT SUNDAY FOR COZ060-073-075-
082.
&&
$$
31/31
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
201 AM EDT SUN MAY 13 2012
.PREV DISCUSSION...
EVENING UPDATE...
/ISSUED 1011 PM EDT SAT MAY 12 2012/
A LOW PRESSURE SYSTEM OVER THE LOWER MISSISSIPPI VALLEY REGION WILL
GRADUALLY LIFT TO THE NORTHEAST TONIGHT... SPREADING AMPLE SHOWERS
AND A FEW THUNDERSTORMS ACROSS THE DEEP SOUTH OVERNIGHT. WEAK
INSTABILITIES...ABUNDANT LOW LEVEL MOISTURE AND SOME UPPER LEVEL
FORCING WILL WARRANT HOLDING ONTO A SLIGHT CHANCE OF THUNDERSTORMS
ACROSS PARTS OF NW AND WEST CENTRAL GA TONIGHT...MAINLY WEST OF AN
ELLIJAY TO MARIETTA TO HAMILTON LINE. STILL EXPECT NUMEROUS SHOWERS
TO SPREAD IN OVER THE FORECAST AREA TONIGHT AND CONTINUE ON SUNDAY.
HAVE TWEAKED THE FORECAST TO ADD SLIGHT CHANCE OF THUNDERSTORMS FOR
THE FAR WESTERN REACHES... BUT THE REST OF THE FORECAST LOOKS ON
TRACK AT THIS TIME. /39
SHORT TERM /TONIGHT THROUGH MONDAY/...
/ISSUED 359 PM EDT SAT MAY 12 2012/
MAIN FORECAST CONCERN WILL BE QPF AND POPS ASSOCIATED WITH
DEVELOPING LOW PRESSURE SYSTEM APPROACHING THE FORECAST AREA FROM
THE WEST. MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THIS FEATURE
HOWEVER THE GFS SEEMS TO HAVE A SLIGHTLY BETTER HANDLE ON IT AND
THE ASSOCIATED PRECIPITATION...THEREFORE MADE MINOR TWEAKED TO MAV
INITIALIZATION. HRRR IS SUGGESTING SOME SCATTERED SHOWER
DEVELOPMENT AHEAD OF THE MAIN SWATH AFTER 21Z THIS EVENING...
WHILE THE MORE WIDESPREAD RAIN SHOULD AFFECT THE WESTERN PORTIONS
AFTER ABOUT 03Z. HAVE THEREFORE KEPT CHANCE POPS THIS AFTERNOON
AND INCREASED TO LIKELY AND CATEGORICAL POPS ACROSS THE
NORTHWESTERN HALF OF THE AREA OVERNIGHT. SOME BREAKS IN THE CLOUD
DECK THIS AFTERNOON HAS ALLOWED CAPE VALUES TO INCREASE SOMEWHAT
SO THERE IS STILL A SLIGHT CHANCE FOR THUNDERSTORMS.
SUNDAY LOOKS TO BE THE WETTEST DAY IN THE SHORT TERM WITH THE
HEAVIEST RAINFALL LIKELY OCCURRING IN THE NORTHERN PORTIONS OF THE
AREA DURING THE MORNING AND SUNDAY OVERNIGHT. LATEST 12Z GFS AND NAM
TIME HEIGHTS ALSO SHOW DEEPEST HIGH RH LAYER INFLUENCING THE AREA ON
SUNDAY WITH LESS MOISTURE ON MONDAY THAN PREVIOUSLY THOUGHT. HAVE
THEREFORE MAINTAINED CATEGORICAL POPS IN THE NORTH... LIKELY POPS
CENTRAL... AND HIGH END CHANCE POPS SOUTH THROUGH SUNDAY. MODELS DO
INDICATED A BIT HIGHER CAPE VALUES AFTER 18Z SUNDAY SO HAVE INCLUDED
CHANCE OF THUNDERSTORMS. THE UPPER LEVEL SHORTWAVE TROUGH AXIS
SHOULD SWING THROUGH THE AREA BY AROUND 18Z MONDAY AND THE WEAK COLD
FRONT ASSOCIATED WITH THE PHASED SURFACE LOW SHOULD PASS AROUND 00Z
TUESDAY...THUS ALLOWING FOR CHANCE POPS TO CONTINUE THROUGH MUCH OF
THE DAY. LESS QPF IS EXPECTED DURING THIS TIME HOWEVER.
FOR TOTAL QPF...HPC GUIDANCE IS OVERALL LEANING MORE TOWARD GFS
AMOUNTS GIVING 48 HOUR RAINFALL TOTALS OF NEAR 2.5 INCHES IN THE
NORTH TO HALF AN INCH IN THE SOUTHEAST BY 00Z TUESDAY. THE HEAVIEST
OF WHICH SHOULD OCCUR SUNDAY MORNING AND SUNDAY OVERNIGHT.
FOR TEMPS...MAV GUIDANCE SEEMS TO HAVE BEEN DOING WELL WITH PROGGED
HIGHS AND LOWS SO MADE ONLY MINOR TWEAKS. MONDAY LOOKS TO BE A BIT
WARMER THAN TUESDAY WITH HIGHS IN THE MID TO UPPER 70S NORTH AND LOW
TO MID 80S SOUTH.
03
LONG TERM /TUESDAY THROUGH SATURDAY/...
/ISSUED 359 PM EDT SAT MAY 12 2012/
MODELS CONTINUE TO HOLD A BROAD TROUGH ACROSS THE SOUTHEAST
THROUGH THE PERIOD. LOW PRESSURE DEVELOPING IN THE CENTRAL GULF
SHOULD BE INTO THE WESTERN CAROLINAS AT THE BEGINNING OF THE
PERIOD...WITH MOST OF THE RAINFALL EAST OF THE CWA. HAVE HELD ON
TO LOW POPS ACROSS THE EASTERN ZONES INTO WEDNESDAY NIGHT. SOME
QUESTION AS TO HOW MUCH MOISTURE LINGERS BEHIND THIS SYSTEM AS
MODELS HOLD THE BROAD UPPER TROUGH ACROSS THE SOUTHEAST AND
REMNANTS OF THE SURFACE FRONT DRIFT ACROSS CENTRAL OR SOUTH
GEORGIA. HAVE NOT ADDED ANY POPS TO THE LAST FEW DAYS DUE TO LOW
CONFIDENCE IN THE MODEL SOLUTION.
41
HYDROLOGY...
/ISSUED 359 PM EDT SAT MAY 12 2012/
HPC 1-3 DAY QPF TOTAL ENDING 12Z TUESDAY SHOWS 2.5 TO 3.00 ACROSS
EXTREME NORTH GEORGIA AND LESSER AMOUNTS ELSEWHERE. 6 HOUR FFG
VALUES ARE AROUND 4.5 INCHES OVER THE NORTH. WITH EXPECTED
RAINFALL SPREAD OVER A COUPLE OF DAYS...THINK WE SHOULD BE ABLE TO
HANDLE THESE FORECAST AMOUNTS...BUT WILL HAVE TO WATCH FOR
LOCALIZED PROBLEMS ON THE CREEKS AND RIVERS ACROSS THE NORTH.
41
&&
.AVIATION...
06Z UPDATE...
SHOWERS HAVE MOVED INTO WESTERN TAF SITES AND WILL CONTINUE TO
SLIDE NORTHEAST. RAIN SHOULD GENERALLY CONTINUE THROUGH TODAY AND
RAIN CHANCES WILL BEGIN TO DECREASE TONIGHT. FORECAST INSTABILITIES
INDICATE ENOUGH OF A CHANCE FOR THUNDER TO MENTION THIS AFTERNOON
IN THE TAFS. MAIN CHALLENGE IS HOW LOW CIGS AND VSBYS WILL GO THIS
MORNING. IFR CIGS EXPECTED FOR NORTHERN TAF SITES BUT NOT QUITE AS
LOW AS THE SOUTHERN SITES. FOR ATL SITES AND AHN...DO NOT EXPECT
TO SEE MUCH IMPROVEMENT IN CIGS TODAY WITH MVFR FORECAST FOR THE
AFTERNOON. WINDS WILL REMAIN SOUTHEAST TODAY AND WILL NOT COME
AROUND TO THE SW UNTIL TOWARD THE END OF THE ATL TAF PERIOD.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON WIND. MEDIUM CONFIDENCE ON CIGS AND VSBYS. LOW
CONFIDENCE ON THUNDER FORECAST THIS AFTERNOON.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 73 62 79 60 / 70 60 50 40
ATLANTA 73 63 77 61 / 80 50 40 20
BLAIRSVILLE 65 59 74 56 / 80 80 50 40
CARTERSVILLE 71 63 77 56 / 80 70 40 30
COLUMBUS 79 65 81 61 / 60 50 40 20
GAINESVILLE 70 62 77 59 / 80 80 50 40
MACON 79 63 82 61 / 50 50 50 20
ROME 75 62 80 57 / 80 60 40 30
PEACHTREE CITY 75 60 78 57 / 80 50 40 20
VIDALIA 81 67 84 65 / 50 50 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
1052 AM EDT SUN MAY 13 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION FROM NORTHWEST TO
SOUTHEAST TODAY...NOT CLEARING OUR SOUTHERN AREAS UNTIL THIS
EVENING. THIS FRONT COULD BRING WIDELY SCATTERED SHOWERS...MAINLY
THIS AFTERNOON AND EARLY EVENING. THE FRONT WILL STALL JUST TO OUR
SOUTH TONIGHT...ALLOWING SEVERAL DISTURBANCES TO MOVE ALONG
IT...BRINGING THE POTENTIAL FOR RAIN...SOME OF WHICH COULD BE ON
THE HEAVY SIDE ON TUESDAY.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 1050 AM...REGIONAL RADARS CONTINUED TO INDICATE DRY
CONDITIONS ACROSS OUR AREA...WITH A LINE OF BROKEN SHOWERS OVER
THE ST LAWRENCE VALLEY REGION. SKIES HAVE BECOME PARTLY SUNNY
ACROSS MUCH OF THE AREA WITH JUST SOME SCT HIGH LEVEL CIRRUS
CLOUDS...EXCEPT FOR ACROSS THE WESTERN ADIRONDACKS WHERE THICKER
CLOUD COVER EXISTS DUE TO PROXIMITY TO A COOL FRONT SLOWLY SAGGING
SOUTHWARD.
THIS COOL FRONT WILL PROVIDE THE FOCUS FOR ISOLATED TO WIDELY
SCATTERED SHOWERS THIS AFTERNOON INTO EARLY EVENING. NEAR TERM
MODEL GUIDANCE INCLUDING THE HRRR AND THE LOCAL HIRESWRF INDICATE
THE POTENTIAL FOR SOME POP UP CONVECTIVE SHOWERS. COVERAGE LOOKS
TO BE ISOLATED TO POTENTIALLY SCATTERED SO RAISED THE POPS
SLIGHTLY TO AROUND 30 PERCENT FOR MOST AREAS COINCIDING FOR WHEN
THE FRONT APPROACHES.
DESPITE FAIRLY STEEP MID LEVEL LAPSE RATES...AN INVERSION BETWEEN
600-700 MB SHOULD PREVENT UPDRAFTS FROM GROWING VERY TALL AND WITH
SURFACE DEWPOINTS IN THE UPPER 40S TO LOWER 50S CAPE VALUES WILL
BE RATHER MEAGER ONLY A FEW HUNDRED J/KG. SO WILL CONTINUE TO OMIT
MENTION OF THUNDER BUT WILL CONTINUE TO MONITOR INTO THE AFTERNOON
IF GREATER INSTABILITY THAN EXPECTED DEVELOPS.
SUNSHINE IN MOST AREAS FOR A WHILE TODAY WILL ALLOW TEMPS TO WARM
INTO THE 70S BY AFTERNOON...TOUCHING 80 FROM ALBANY SOUTHWARD
AND EVEN A LITTLE HIGHER IN THE MID HUDSON VALLEY. THE ONLY
EXCEPTION WOULD BE OUR FAR NORTHWESTERN ZONES...WHERE THE
AFOREMENTIONED FRONT WILL BE WORKING THROUGH WITH MORE CLOUDS AND
SCATTERED SHOWERS...HOLDING TEMPERATURES IN THE 60S.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY NIGHT/...
A STRONGER SHORT WAVE...ALREADY EVIDENT ON THE H20 WATER LOOP MOVING
INTO GA...IS PROGGED BY ALL MODEL GUIDANCE TO TRACK UP ALONG THE
STALLED FRONT TONIGHT...OVERSPREADING THE REGION WITH MORE NUMEROUS
SHOWERS OVERNIGHT INTO MONDAY. AT THIS POINT...INSTABILITY LOOKS
MARGINAL SO WILL CONTINUE TO OMIT THUNDER BUT LATER CREWS WILL
CONTINUE TO MONITOR THE EVOLUTION OF THIS FIRST SYSTEM FOR POTENTIAL
INSTABILITY. MORE ABOUT THE QPF CAN BE FOUND IN OUR HYDROLOGY
SECTION.
AT THIS POINT...IT LOOKS AS THIS SHORT WAVE WILL MOVE TO OUR
NORTHEAST LATER MONDAY. WHILE NO REAL CLEARING IS EXPECTED...THERE
MIGHT BE A BREAK IN THE SHOWERS OR STEADY RAIN...TAPERING TO
SCATTERED LIGHTER SHOWERS LATER MONDAY INTO EARLY MONDAY NIGHT.
THERE COULD BE A FEW BREAKS OF SUNSHINE BUT THAT WOULD THE EXCEPTION
RATHER THAN THE RULE.
THE BREAK WILL NOT LAST LONG. THE NEXT DISTURBANCE...NOW DIVING
THROUGH WYOMING...LOOKS TO HEAD OUR WAY AND SHOULD BE THE STRONGEST
ONE. THIS ONE IS PROGGED TO INITIALLY TRACK SE...AND QUITE POSSIBLY
ESTABLISH A TROPICAL CONNECTION...BRINGING PWAT AIR WELL OVER AN
INCH NOSING INTO AREA VIA AN INCREASING LOW LEVEL SOUTHERLY JET WITH
VALUES UP TO 40 KTS. AT THE SAME TIME...MUCH OF OUR REGION LOOK TO
BE UNDER THE LEFT SIDE OF THE EXIT REGION OF AN UPPER LEVEL JET
WHICH WILL AID IN ASCENT. THIS AIR WILL TRACK ALONG AN INCREASING
CONVERGENT ZONE (STALLED OUT FRONT STILL JUST DRAPED OVER US OR
JUST TO OUR EAST).
THE POTENTIAL IS THERE FOR A MODERATE TO EVEN HEAVY RAINFALL EVENT.
MORE ABOUT THIS WILL BE DISCUSSED IN OUR HYDRO SECTION.
WITH CLOUDS AND SHOWERS/RAIN...THERE WILL BE LITTLE DIURNAL RANGE IN
TEMPERATURES MONDAY AND ESPECIALLY TUESDAY. HOWEVER...DUE TO THE
SEMI-TROPICAL NATURE OF THE AIR MASS...HIGHS ON MONDAY WILL STILL
REACH AROUND 70 IN VALLEY AREAS...60S HIGHER TERRAIN. ON
TUESDAY...EVERYONE SHOULD STAY IN THE 60S. OVERNIGHT LOWS SUNDAY AND
MONDAY WILL BE MAINLY IN THE 50S.
WHILE THE TIMING OF THIS WAVE HAS BECOME MORE CONFIDENT...THERE IS
STILL UNCERTAINTY AS TO HOW MUCH RAIN WOULD ULTIMATELY FALL AND
WHERE THE HEAVIEST OF IT WILL BE. AGAIN...MORE DISCUSSION ON THE QPF
AND POTENTIAL HYDRO EFFECTS CAN BE FOUND IN OUR HYDROLOGY
SECTION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
13/00Z MEDIUM RANGE MODELS ARE IN RELATIVELY GOOD AGREEMENT THIS
MORNING WITH JUST SOME TIMING DIFFERENCES AS TO WHEN THE STEADIEST
PCPN WILL END TUESDAY NIGHT INTO WEDNESDAY. THE GFS IS THE FASTEST
WITH THE STEADY RAIN GENERALLY ENDING TUESDAY EVENING. THE NAM/ECMWF
KEEP STEADY RAIN OVER THE FORECAST AREA MOST OF THE NIGHT WITH JUST
SCATTERED SHOWERS FOR WEDNESDAY/WEDNESDAY EVENING. HAVE FORECAST
LIKELY POPS FOR THE SOUTHEAST TWO THIRDS OF THE FORECAST THROUGH
TUESDAY NIGHT...THEN POPS DECREASING TO 30 TO 40 PERCENT ON
WEDNESDAY...AND ONLY SLIGHT CHANCE POPS WEDNESDAY EVENING. FROM
LATE WEDNESDAY NIGHT THROUGH SATURDAY HAVE FORECAST DRY CONDITIONS.
GFS INDICATES THE POTENTIAL FOR SOME CONVECTIVE SHOWERS FRIDAY
AFTN/EVENING AS A WEAK FRONTAL BOUNDARY DIPS SOUTH OUT OF CANADA.
HAVE CHOSEN TO IGNORE THIS POSSIBLE CONVECTION FOR NOW AND KEPT THE
FORECAST DRY.
TEMPERATURE WISE...WITH THE EARLIER DEPARTURE OF THE SURFACE/UPPER
LEVEL SYSTEMS AND NO NEW SYSTEMS EXPECTED THROUGH SATURDAY...HIGH
TEMPS WILL BE FORECAST CONSIDERABLY HIGHER THAN PREVIOUS
FORECASTS...ESPECIALLY FOR WEDNESDAY AND THURSDAY. HIGHS WEDNESDAY
AND THURSDAY WILL BE IN THE MID 60S TO MID 70S...AND GENERALLY IN
THE 70S FRIDAY AND SATURDAY. LOWS TUESDAY NIGHT WILL BE IN THE UPPER
40S TO MID 50S...IN THE 40S TO LOWER 50S WEDNESDAY THROUGH FRIDAY
NIGHTS WITH SOME UPPER 30S IN COLDER HIGHER TERRAIN LOCATIONS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE KGFL/KALB/KPOU/KPSF
TAF SITES THROUGH THE 24 HOUR PERIOD ENDING 12Z MONDAY. BKN/OVC
MID/HI CLOUDS WILL PREVAIL AT THE TAF SITES INTO THIS EVENING. FOR
TONIGHT CLOUDS WILL LOWER TO AROUND 6000 FEET...EXCEPT AROUND 10000
FEET AT KPOU/KPSF DURING THE EVENING...THEN LOWER TO 3500-4000 FEET
TOWARD SUNRISE MONDAY AS LIGHT RAIN SPREADS INTO THE REGION..
A COLD FRONT WILL GRADUALLY SETTLE SOUTHWARD THIS AFTERNOON...
PASSING KGFL AROUND 13/23Z...KALB AROUND 14/01Z. THE FRONT WILL
EVENTUALLY BECOME NEARLY STATIONARY IN THE VICINITY OF KPSF/KPOU
LATER TONIGHT. ISOLATED SHOWERS WILL BE POSSIBLE ALONG AND BEHIND
THIS FRONT...BUT DUE TO VERY LIMITED AREAL COVERAGE...HAVE ONLY
INDICATED VCSH AT KGFL/KALB TO ACCOUNT FOR THIS REMOTE POSSIBILITY.
AS LIGHT RAIN SPREADS ACROSS ALL TAF SITES BETWEEN 09Z AND 10Z
SUNDAY NIGHT...EXPECT CIGS/VSBYS TO LOWER SOMEWHAT...BUT REMAIN IN
THE VFR RANGE THROUGH 12Z MONDAY.
CALM OR LIGHT AND VARIABLE WINDS EXPECTED AT THE TAF SITES THROUGH
MID MORNING...THE BECOMING WEST OR SOUTHWEST BY AFTERNOON...
GENERALLY 10 KTS OR LESS. AT KPSF THERE COULD BE WINDS GUSTS UP TO
15 KTS. SURFACE WINDS WILL BECOME NORTHERLY AT KGFL/KALB BEHIND THE
FRONT TONIGHT AT 5 KTS OR LESS...WITH LIGHT OR CALM WINDS AT
KPOU/KPSF.
.OUTLOOK...
LATE SUN NT...VFR-MVFR. -SHRA LIKELY
MON-WED...MVFR/IFR. SHRA OR RA LIKELY.
WED NT-THU...VFR. NO SIG WX.
&&
.FIRE WEATHER...
ONE MORE MAINLY DRY AND WARM TODAY WITH AT LEAST SOME SUNSHINE
THROUGH MIDDAY. A FEW SHOWERS COULD SKIM OUR NORTHERN REGIONS THIS
MORNING AND BY AFTERNOON...THERE A SLIGHT CHANCE OF SHOWER ANYWHERE.
ANY SHOWER ACTIVITY WILL LIKELY ONLY ADD UP TO A FEW HUNDREDTHS OF
AN INCH OR SO.
AFTERNOON RH VALUES WILL NOT BE QUITE AS LOW AS
YESTERDAY...GENERALLY BOTTOMING OUT IN THE 30S...EXCEPT 40S FAR
NORTHWEST.
A LIGHT SOUTH WIND WILL BECOME WESTERLY 5 TO 15 MPH...TURNING
NORTHWEST DURING THE AFTERNOON.
AN UNSETTLED AND POTENTIALLY WET WEATHER LOOKS TO TAKE PLACE TONIGHT
THROUGH AT LEAST THROUGH TUESDAY...IF NOT INTO WEDNESDAY. THERE IS
THE POTENTIAL FOR NUMEROUS SHOWERS LATER TONIGHT INTO MONDAY
FOLLOWED BY A WIDESPREAD SOAKING RAIN COME TUESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED THROUGH MONDAY.
ANY WIDELY SCATTERED SHOWERS TODAY SHOULD BE LIGHT WITH ANY AVERAGE
RIVER BASIN QPF WELL UNDER A QUARTER OF AN INCH.
HOWEVER...TONIGHT INTO MONDAY...A ROUND OF SHOWERS OR EVEN A PERIOD
OF STEADY RAIN LOOKS TO PRODUCE RIVER BASIN AVERAGE QPF RANGING
FROM AROUND A QUARTER OF AN INCH IN OUR NORTHWESTERN ZONES...TO
AROUND HALF AN INCH MOST OTHER AREAS. THIS RAINFALL SHOULD NOT HAVE
ANY REAL EFFECT ON RIVERS AND STREAMS OTHER THAN SOME MINOR RISES.
THEN...ANOTHER ROUND OF POTENTIALLY HEAVIER RAIN LOOKS TO MOVE INTO
THE REGION MONDAY NIGHT INTO TUESDAY. THIS RAIN COULD BE ASSOCIATED
WITH SOME OF TROPICAL CONNECTION AND COULD BRING 1-2 INCHES OF
RAINFALL TO MUCH OF THE AREAS (ONCE AGAIN LIGHTER AMOUNTS OF AROUND
HALF AN INCH TO OUR NORTHWESTERN ZONES).
THIS RAIN WOULD AT THE VERY LEAST BRING SIGNIFICANT WITHIN BANK
RISES ON RIVERS AND STREAMS (EXCEPT ONLY MINOR RISES IN OUR
NORTHWESTERN ZONES). SOME RIVERS FROM THE EASTERN MOHAWK VALLEY AND
POINTS SOUTH AND EAST...COULD REACH BACK INTO THE ACTION STAGE
LEVEL.
BASED ON THIS PROJECTED RAINFALL...FLOODING IS UNLIKELY (LESS 70
PERCENT). HOWEVER...MORE RAIN IS CERTAINLY POSSIBLY THAN WHAT WE ARE
FORECASTING. OF COURSE...EVEN WITHOUT ANY FLOODING...PONDING OF
WATER IS POSSIBILITY IN AREAS OF POOR DRAINAGE.
RAINFALL OR SHOWERS MIGHT LINGER INTO WEDNESDAY BEFORE SOME DRY
WEATHER IS FORECAST LATER IN THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV/JPV
NEAR TERM...HWJIV/JPV
SHORT TERM...HWJIV
LONG TERM...GJM
AVIATION...GJM
FIRE WEATHER...HWJIV
HYDROLOGY...HWJIV
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1018 AM EDT SUN MAY 13 2012
.UPDATE...
WHILE AREA OF WIDESPREAD RAIN CONTINUES TO PUSH NORTHEASTWARD...
SCATTERED SHOWERS SHOULD CONTINUE THROUGHOUT THE DAY. HAVE
INCREASED POPS SOME TO THE SOUTH AS LOOKS TO BE A GOOD CHANCE FOR
CONTINUED MOISTURE ADVECTION AND SHOWER DEVELOPMENT. RUC FORECAST
CAPE VALUES ARE AROUND 1000 J/KG IN THE WESTERN PORTION OF THE
AREA BY 00Z WITH AND A MODIFIED 12Z FFC SOUNDING GAVE NEAR 600
J/KG BY 21Z... THEREFORE WILL MAINTAIN A SLIGHT CHANCE OF TS THIS
AFTERNOON. ALL ELSE OF FORECAST APPEARED TO BE ON TRACK.
03
&&
.PREV DISCUSSION... /ISSUED 434 AM EDT SUN MAY 13 2012/
SHORT TERM /TODAY THROUGH MONDAY/...
MUCH NEEDED RAIN CONTINUES ACROSS MOST OF THE CWA THIS MORNING AND
HEAVY RAIN CONTINUES TO BE THE MAIN THREAT. HIGH CHANCES CONTINUE THROUGH
TONIGHT ACROSS NORTH AND WEST GEORGIA AND THEN BEGIN TO DECREASE
POPS ON MONDAY.
TROUGH AXIS REMAINS OVER THE MISSISSIPPI VALLEY THIS MORNING WHILE
THE SFC LOW WAS EXITING MISSISSIPPI. THIS SYSTEM HAS RESULTED IN
HIGH CHANCE OF POPS ACROSS MOST OF THE CWA. AREA OF RAIN THIS
MORNING WILL CONTINUE TO PUSH NORTHEAST AND BY THIS AFTERNOON BEST
RAIN CHANCES WILL SHIFT TO THE NORTH WHILE THE LEAST FAVORABLE AREA
FOR PRECIP WILL BE ACROSS THE SOUTHEAST. THE CLOSE PROXIMITY OF THE
SFC LOW /WITH THE CWA IN THE WARM SECTOR/ AND THE UPPER LEVEL
FORCING FROM THE TROUGH WILL ALLOW FOR INCREASED THUNDER CHANCES
THIS AFTERNOON. GFS MU CAPE INDICATES BEST CHANCE FOR THUNDER ACROSS
THE WESTERN PORTION OF THE CWA WITH VALUES AROUND 1000 J/KG.
ALTHOUGH DECENT INSTABILITY THIS AFTERNOON WILL ALLOW FOR
THUNDERSTORM DEVELOPMENT...SEVERE STORMS ARE NOT EXPECTED. SPC
CURRENTLY ONLY HAS THE AREA IN SEE TEXT. TONIGHT...WITH UPPER LEVEL
SYSTEM STILL NEARBY AND SFC LOW MOVING OVER NW GA...INSTABILITY IS
LOW BUT ENOUGH TO POSSIBLY PRODUCE THUNDERSTORMS SO INCLUDED A SLIGHT
CHANCE.
ON MONDAY MAIN TROUGH AXIS MOVES INTO THE CWA BUT A SHORTWAVE
DEVELOPS IN THE LONG WAVE TROUGH WEST OF THE AREA. IT WILL BE AWHILE
BEFORE WE CAN PUSH THE LONG WAVE TROUGH OUT OF OUR AREA. THIS WILL
ALLOW OUR SHOWER AND THUNDERSTORM CHANCE TO CONTINUE BUT CHANCES
WILL BEGIN TO DECREASE AS THE SFC LOW CONTINUES MOVING ALONG THE
APPALACHIANS AND SFC FRONT PUSHING INTO GEORGIA.
MAIN CONCERN THROUGH THE SHORT TERM CONTINUES TO BE HEAVY RAIN
THREAT. SEE THE HYDROLOGY SECTION FOR DETAILS.
CLOUD COVERAGE THROUGH THE SHORT TERM WILL HELP TO MODERATE TEMPS
AND KEEP MOST OF THE CWA IN THE 70S TODAY. MAV/MET TEMPS ARE VERY
SIMILAR THROUGH MONDAY. STUCK CLOSE TO A MAV/MET BLEND.
11
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
EXTENDED PROGS CONTINUE TO SHOW A BROAD UPPER TROF OVER THE
SOUTHEAST U.S. INTO THURSDAY BEFORE UPPER RIDGE BEGINS TO BUILD IN
FROM THE WEST THURSDAY NIGHT/FRIDAY. AT THE SURFACE MODELS
MAINTAIN WAVY FRONTAL BOUNDARY SOMEWHERE ACROSS CENTRAL GEORGIA
INTO TUESDAY NIGHT...BEFORE SHIFTING INTO SOUTH GEORGIA WEDNESDAY.
WITH THIS BOUNDARY STILL IN THE VICINITY AND UPPER TROF OVER THE
REGION WILL NEED TO HOLD ON TO SLIGHT CHANCE TO CHANCE POPS FOR
MUCH OF THE COUNTY WARNING AREA INTO TUESDAY...THEN FOCUS SHIFTING
MORE TO EAST SIDE OF THE STATE TUESDAY NIGHT/WEDNESDAY WITH MODELS
SHOWING BEST MOISTURE OVER THE CAROLINAS. WILL KEEP FORECAST DRY
THURSDAY INTO SATURDAY WITH WEAK RIDGE OVER THE AREA. HOWEVER...
WITH BOTH ECMWF AND GFS HINTING AT A COASTAL LOW DEVELOPING ALONG
THE MID ATLANTIC/SOUTHEAST COAST OVER THE WEEKEND WILL NEED TO
KEEP A CLOSE WATCH ON FUTURE RUNS TO SEE HOW MODELS HANDLE THIS
FEATURE. HAVE GONE WITH JUST CLOUDS FOR NOW.
49
HYDROLOGY...
HPC DAY 1-2 QPF STILL INDICATES 1-2 INCHES ACROSS NORTH GEORGIA WITH
2 INCHES ACROSS THE NORTHEAST AND 1 INCH ACROSS CENTRAL GEORGIA.
THIS IS VERY CLOSE TO THE TOTALS ADVERTISED IN THE FORECAST. AT THIS
TIME IT APPEARS THE RIVERS/CREEKS/STREAMS SHOULD BE ABLE TO HANDLE
THIS AMOUNT...ESPECIALLY GIVEN THAT THE AMOUNTS ARE SPREAD OUT OVER
A FEW DAYS. WILL CONTINUE TO MONITOR THOUGH FOR ANY LOCALIZED
PROBLEMS THAT MAY ARISE ON THE NORTHERN CREEKS AND STREAMS.
11
AVIATION...
12Z UPDATE...
IFR TO MVFR CONDITIONS EXPECTED THIS MORNING. WIDESPREAD -RA THIS
MORNING CONTINUES TO PUSH NORTHEASTWARD ACROSS THE FORECAST
AREA... BECOMING MORE SCATTERED IN COVERAGE AFTER 14Z AND
PERSISTING THROUGHOUT THE MAJORITY OF THE TAF PERIOD. CIGS HAVE
BEEN GRADUALLY LOWERING AND SHOULD APPROACH OVC007 FOR MOST AREAS
BY 14Z OR EARLIER AND IMPROVING TO BKN025 NEAR 18Z. THROUGH TODAY
WINDS SHOULD STAY OUT OF THE SOUTHEAST UNDER 10KTS FOR MOST AREAS
WITH SOME GUSTS LESS THAN 20KTS POSSIBLE BY 18Z. CIGS SHOULD LOWER
AGAIN TO IFR LEVEL NEAR 700 FT AFTER 06Z MONDAY AND WINDS LOOK TO
VEER TO SOUTHWESTERLY NEAR THE END OF THE FORECAST. VISBYS SHOULD
REMAIN NEAR MVFR TO VFR. TOOK OUT MENTION OF THUNDER THIS
AFTERNOON AS CHANCE LOOKS SLIGHT... BUT WILL BE UPDATED IF NEEDED.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON PRECIP AND CIGS THIS AFTERNOON.
HIGH CONFIDENCE ON ALL ELSE.
03
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 72 61 79 60 / 100 80 50 40
ATLANTA 73 62 77 61 / 100 70 30 20
BLAIRSVILLE 65 59 72 53 / 100 90 60 50
CARTERSVILLE 72 60 77 57 / 100 80 40 20
COLUMBUS 79 64 81 62 / 70 50 30 20
GAINESVILLE 69 61 76 59 / 100 90 40 40
MACON 79 64 80 62 / 90 50 30 20
ROME 76 62 79 58 / 100 80 40 30
PEACHTREE CITY 75 60 77 57 / 90 60 30 20
VIDALIA 82 66 84 65 / 100 40 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11/03
LONG TERM....49
AVIATION...03
AREA FORECAST DISCUSSION...CORRECTED
NWS WILMINGTON NC
746 AM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM SUNDAY...RADAR SHOWS THE BAND OF SHOWERS ALONG THE SC
COAST IS DEVELOPING ABOUT 30-40 MILES FARTHER EAST THAN WAS
EXPECTED. THE 06Z NAM WAS EVEN WORSE THAN THE 00Z RUN WITH THIS
ACTIVITY. THE LACK OF RECENT HRRR MODEL DATA DUE TO SUPERCOMPUTER
PROBLEMS AT NCEP LEAVES US WITH LINEAR EXTRAPOLATION AS OUR BEST
WEAPON THIS MORNING. WE`RE FORECASTING THE CURRENT ACTIVITY TO
CONTINUE STREAMING NORTH-NORTHWEST ACROSS MYRTLE BEACH AND CONWAY
INTO MARION...DILLON AND EVENTUALLY LUMBERTON. SHOWERS WILL PROBABLY
DEVELOP WEST OF THE MAIN AXIS ACROSS THE SC PEE DEE REGION AS
WELL...BUT WITH AREAL COVERAGE ONLY IN THE 40-50 PERCENT RANGE. DRY
AIR IN THE CAPE FEAR REGION SHOULD INSULATE WILMINGTON FROM RAINFALL
TODAY. OTHERWISE THE SYNOPTIC REASONING GIVEN EARLIER IS STILL VALID
ONCE THE SPATIAL ADJUSTMENT TO THE EAST IS MADE. PREVIOUS DISCUSSION
FROM 3 AM FOLLOWS...
HIGH PRESSURE WELL TO OUR EAST AND LOW PRESSURE DEVELOPING OVER
MISSISSIPPI ARE CREATING A SOUTHEAST SURFACE FLOW ACROSS THE COASTAL
CAROLINAS. THIS WARM ONSHORE WIND HAS SO FAR HELD TEMPERATURES AT
THE BEACHES IN THE 70S...WHILE JUST A FEW MILES INLAND CALM SURFACE
WINDS WITHIN A NOCTURNAL RADIATIONAL INVERSION HAVE ALLOWED
TEMPERATURES TO PLUNGE INTO THE UPPER 50S.
INCREASING LIFT ON THE 300K THETA SURFACE JUST AHEAD OF A
PSEUDO-WARM FRONT MOVING IN FROM THE SOUTH CAROLINA COAST THIS
MORNING SHOULD CREATE AT LEAST A FEW HOURS OF LIGHT TO MODERATE
SHOWERS...MOST STRONGLY AFFECTING THE CORRIDOR FROM GEORGETOWN AND
KINGSTREE UP THROUGH MARION...FLORENCE...DILLON AND BENNETTSVILLE
THROUGH EARLY THIS AFTERNOON. ALTHOUGH MOST OF THESE AREAS WILL SEE
MEASURABLE RAINFALL WE ANTICIPATE ACTUAL RAINFALL AMOUNTS TO REMAIN
LESS THAN TWO-TENTHS OF AN INCH. CHANCES FOR RAIN FALL TO LESS THAN
50-50 FOR MYRTLE BEACH...WHITEVILLE AND ELIZABETHTOWN. EVEN FARTHER
EAST IN THE WILMINGTON AREA IT SHOULD REMAIN DRY TODAY WITH THE
DEEPER MOISTURE AND LIFT REMAINING TOO FAR INLAND. THE CLOUD AND
PRECIPITATION PATTERN WILL STRONGLY INFLUENCE HIGH TEMPERATURES
TODAY WITH THE WARMEST READINGS (UPPER 70S) EXPECTED JUST INLAND
FROM THE COAST NEAR WILMINGTON. MID 70S SHOULD PREVAIL FARTHER
INLAND...AND IT`S NOT IMPOSSIBLE FOR HIGHS TO REMAIN EVEN A LITTLE
COOLER THAN THAT IF DENSE CLOUDS AND SHOWERS LINGER ON BEYOND 2-3 PM.
THERE SHOULD BE A LULL IN THE COVERAGE OF PRECIPITATION ACROSS THE
EASTERN CAROLINAS LATE THIS AFTERNOON INTO THE EVENING HOURS.
REDEVELOPMENT OF SHOWERS IS THEN EXPECTED LATE ACROSS THE PEE DEE
REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL WATERS.
ALTHOUGH FORECAST SOUNDINGS SHOW NO INVERSION LAYERS ALOFT TO
INHIBIT CONVECTION...ENVIRONMENTAL LAPSE RATES NEAR MOIST ADIABATIC
WILL NOT PROMOTE DEEP CONVECTION UNTIL BETTER SYNOPTIC FORCING
ARRIVES ON MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...A WET SHORT TERM ON TAP AS A SLOW MOVING LOW
PRESSURE SYSTEM BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE
EASTERN CAROLINAS.
STILL UNCERTAINTY IN TIMING...BUT EXPECT SHOWERS TO BE ONGOING AT
THE START OF THE PERIOD...ESPECIALLY ACROSS THE WESTERN HALF OF THE
ILM CWA...AND BE IMPACTING THE ENTIRE AREA BY MONDAY AFTN. THESE
SHOWERS ARE DUE TO THE ADVANCE OF A SLOWLY MOVING LOW PRESSURE
SYSTEM SPAWNED BY IMPULSES ROTATING DOWN A DEEP...POSITIVELY TILTED
UPPER TROUGH DROPPING OUT OF THE MIDWEST. THE FIRST OF THESE
IMPULSES PUSHES INTO NEW ENGLAND LATE MONDAY AND TRAILS A COLD FRONT
INTO THE REGION. THIS FRONT GETS VERY LITTLE PUSH DUE TO THE
ORIENTATION OF UPPER FEATURES...AND BECOMES STALLED SOMEWHERE ACROSS
THE EASTERN MID-ATLANTIC AND SOUTHEAST. THIS BOUNDARY ACTS A
FOCUSING MECHANISM FOR CONTINUED ROUNDS OF HEAVY RAINFALL AND
THUNDERSTORMS THROUGH TUESDAY.
THE HEAVIEST RAINFALL WILL OCCUR MONDAY AFTN THROUGH TUESDAY
MORNING. THE COMBINATION OF SOME ENHANCED UPPER DIFLUENCE...PWATS
APPROACHING 1.75 INCHES (NEARLY 2 STD DEVIATIONS ABOVE
NORMAL)...RICH THETA-E AIR...10000 FT OF WARM CLOUD DEPTH...AND
CONVERGENCE ALONG THE STALLED BOUNDARY ALL POINT TOWARDS
WIDESPREAD SHOWERS/THUNDERSTORMS WITH HEAVY RAIN. ALTHOUGH BEST
MOISTURE TRANSPORT IS FOCUSED JUST NORTH OF THE ILM CWA...ENHANCED
MOIST ADVECTION FROM SE FLOW OFF THE GULF STREAM SHOULD PROVIDE
SOME HEAVIER RAIN. WILL BUMP POP TO CATEGORICAL MONDAY
AFTN/NIGHT...FALLING TO CHC BY TUE AFTN...WITH TOTAL QPF ABOVE 1
INCH POSSIBLE. WILL NOTE THAT ISOLATED HEAVIER TOTALS ARE
DEFINITELY POSSIBLE...SINCE DEEP SOUTHERLY FLOW BECOMES BOUNDARY
PERPENDICULAR...WHICH FAVORS TRAINING ECHOES FROM SOUTH TO NORTH
AS THE FRONT MAKES VERY LITTLE PROGRESS EASTWARD. SPC DOES HAVE
THE AREA IN A "SEE TEXT" FOR MONDAY...AND DECENT INSTABILITY WILL
EXIST AHEAD OF THE FRONT...BUT OTRW SEVERE PARAMETERS LOOK QUITE
WEAK AND EXPECT MORE OF A HEAVY RAIN THREAT THAN A SEVERE THREAT.
TEMPS WILL BE BELOW CLIMO MONDAY DUE TO CLOUDS AND RAIN...IN THE
UPPER 70S...WITH LOWS WELL ABOVE CLIMO ONLY FALLING INTO THE MID
60S. SIMILAR ON TUESDAY WITH CONTINUED CLOUDS AND SHOWERS...KEEPING
MAX TEMPS JUST BELOW CLIMO AROUND 80 AND MINS ONCE AGAIN FALLING
ONLY INTO THE LOW/MID 60S AT NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...NEARLY STATIONARY FRONT WILL STILL BE OVER THE
AREA EARLY WEDNESDAY AS DEEP UPPER TROUGH AXIS MOVES OVERHEAD. THIS
WILL PROVIDE THE IMPETUS FOR CONTINUED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTNS OF WED AND THU. THE
KICKER NORTHERN STREAM S/W THEN DROPS SOUTHWARD OUT OF CANADA AND
FINALLY PUSHES THE COLD FRONT OFFSHORE THURSDAY. THIS ALLOWS THE
COLUMN TO BEGIN TO DRY OUT WITH SOME WEAK SUBSIDENCE BEHIND THE
DEPARTING TROUGH...BUT DIURNAL SHOWERS ARE STILL POSSIBLE FRI/SAT.
WILL CARRY CHC POP WED/THU WITH SCHC FRI/SAT...BUT THE ACTIVITY
FRI/SAT SHOULD BE MUCH MORE ISOLATED IN COVERAGE.
BOTH GFS AND EURO DEPICT THE UPPER TROUGH CUTTING OFF NEAR 70 WEST
AND SPAWNING A HYBRID-TYPE SURFACE LOW WELL OFFSHORE. THIS IS
FURTHER EAST THAN PREVIOUS RUNS AND MEANS LESS OF A RAIN CHANCE FOR
THE WKND THAN EARLIER GUIDANCE HAD SUGGESTED. FEEL NO REASON TO
CHANGE INHERITED SCHC ATTM.
TEMPS WILL REMAIN FAIRLY UNIFORM THROUGH THE EXTENDED...WITH HIGHS A
DEGREE OR SO BELOW CLIMO AND MINS AT NIGHT A DEGREE OR TWO ABOVE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...SHOWERS MOVING ONSHORE NEAR MYR WILL PRODUCE AT LEAST
MVFR CONDITIONS AT MYR/CRE THROUGH 14-16Z. THE CHANCE OF IFR
CONDITIONS IS LOW...BUT IF IT DOES OCCUR IT WOULD BE VERY BRIEF AND
ASSOCIATED WITH THE ISOLATED MODERATE SHOWERS AT MYR/CRE. THIS
SHOWER ACTIVITY WILL BE MOVING FURTHER INLAND ON SOUTHEASTERLY WINDS
STAYING EAST OF FLO...BUT EVENTUALLY AFFECTING THE LBT TERMINAL BY
14Z WITH THE CHANCE OF AT LEAST TEMPO MVFR CONDITIONS. THROUGH
THIS AFTERNOON THE BEST CHANCE OF SHOWERS/MVFR CONDITIONS WILL BE
AT BOTH THE FLO/LBT TERMINALS...WITH LESSER CHANCES OF PRECIPITATION
AND HIGHER CHANCES OF VFR AT THE COASTAL TERMINALS. BUT BY LATE
AFTERNOON THE BEST CHANCE OF PRECIPITATION/MVFR CONDITIONS WILL
SHIFT TO THE COASTAL TERMINALS BEFORE BECOMING VERY ISOLATED OR
ENDING ALL-TOGETHER DURING THE EVENING AS SIGNIFICANT LIFT
DECREASES. THROUGH THE REMAINDER OF THE TAF VALID PERIOD PERIODS
OF MVFR CAN BE EXPECTED. THE CHANCE OF ANY IFR IS LOW.
EXTENDED OUTLOOK...UNSETTLED WEATHER MONDAY THROUGH THE PERIOD WITH
A GOOD CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM SUNDAY...SHOWERS ALONG THE SC COAST WILL CONTINUE
THROUGH MUCH OF THE MORNING AND IN A MORE LIMITED EXTENT INTO THE
EARLY AFTERNOON AS WELL. LATEST OBSERVATIONS SHOW SEAS JUST A TOUCH
HIGHER THAN EARLIER FORECAST...OTHERWISE THIS EARLY MORNING UPDATE
CONTAINS FEW OTHER SIGNIFICANT CHANGES. PREVIOUS DISCUSSION FROM 3
AM FOLLOWS...
HIGH PRESSURE WELL OFFSHORE IS PROVIDING A MODEST SOUTHEAST WIND
ACROSS THE COASTAL WATERS THIS MORNING. LOW PRESSURE DEVELOPING OVER
MISSISSIPPI WILL MOVE TO NEAR CHATTANOOGA TENNESSEE BY LATE
TONIGHT...VEERING OUR WINDS MORE SOUTHERLY WITH A SLIGHT INCREASE IN
WIND SPEEDS EXPECTED. ALTHOUGH THERE ARE NO IDENTIFIABLE FRONTS
ACROSS THE AREA CURRENTLY SHOWERS DEVELOPING ALONG THE SOUTH
CAROLINA COAST THIS MORNING SOUTH OF MYRTLE BEACH ARE ASSOCIATED
WITH A WARM FRONTAL-LIKE STRUCTURE THAT WILL LIFT NORTHWESTWARD AND
INLAND THIS MORNING. THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN
ACROSS THE SC WATERS THIS MORNING...BECOMING MORE ISOLATED IN NATURE
THIS AFTERNOON. MODELS SHOW REDEVELOPMENT OF SHOWERS POSSIBLE LATE
TONIGHT.
WITH ONSHORE WINDS CONTINUING WE EXPECT A VERY GRADUAL INCREASE IN
SEA HEIGHTS THROUGH TONIGHT. BUOYS SHOW SEAS ARE CURRENTLY 2 FT NEAR
SHORE AND 3 FT OUT AT THE FRYING PAN SHOALS BUOY. THESE SEA HEIGHTS
SHOULD BUILD BY ABOUT ONE FOOT BY LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...THE WATERS WILL BE SANDWICHED BETWEEN A VERY
SLOWLY ADVANCING COLD FRONT FROM THE WEST...AND HIGH PRESSURE
RETREATING TO THE EAST...THROUGH THE SHORT TERM. THIS CREATES
SOUTHERLY WINDS MONDAY...VEERING SLIGHTLY TO THE SW TUESDAY AS FRONT
GETS CLOSER TO THE AREA...AT 10-15 KTS THROUGHOUT. ALTHOUGH A WEAK
1FT/11SEC EASTERLY SWELL WILL EXIST IN THE WAVE SPECTRUM...THE
SIGNIFICANT WAVE HEIGHTS WILL BE FORCED PRIMARILY BY THE WIND...WITH
3-5 FT SEAS MONDAY FALLING TO 3-4 FT TUESDAY. ADDITIONALLY...THERE
IS A GOOD CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN TO IMPACT THE WATERS LATE MONDAY AND TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
744 AM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM SUNDAY...RADAR SHOWS THE BAND OF SHOWERS ALONG THE SC
COAST IS DEVELOPING ABOUT 30-40 MILES FARTHER EAST THAN WAS
EXPECTED. THE 06Z NAM WAS EVEN WORSE THAN THE 00Z RUN WITH THIS
ACTIVITY. THE LACK OF RECENT HRRR MODEL DATA DUE TO SUPERCOMPUTER
PROBLEMS AT NCEP LEAVES US WITH LINEAR EXTRAPOLATION AS OUR BEST
WEAPON THIS MORNING. WE`RE FORECASTING THE CURRENT ACTIVITY TO
CONTINUE STREAMING NORTH-NORTHWEST ACROSS MYRTLE BEACH AND CONWAY
INTO MARION...DILLON AND EVENTUALLY LUMBERTON. SHOWERS WILL PROBABLY
DEVELOP WEST OF THE MAIN AXIS ACROSS THE SC PEE DEE REGION AS
WELL...BUT WITH AREAL COVERAGE ONLY IN THE 40-50 PERCENT RANGE. DRY
AIR IN THE CAPE FEAR REGION SHOULD INSULATE WILMINGTON FROM RAINFALL
TODAY. OTHERWISE THE SYNOPTIC REASONING GIVEN EARLIER IS STILL VALID
ONCE THE SPATIAL ADJUSTMENT TO THE EAST IS MADE. PREVIOUS DISCUSSION
FROM 3 AM FOLLOWS...
HIGH PRESSURE WELL TO OUR EAST AND LOW PRESSURE DEVELOPING OVER
MISSISSIPPI ARE CREATING A SOUTHEAST SURFACE FLOW ACROSS THE COASTAL
CAROLINAS. THIS WARM ONSHORE WIND HAS SO FAR HELD TEMPERATURES AT
THE BEACHES IN THE 70S...WHILE JUST A FEW MILES INLAND CALM SURFACE
WINDS WITHIN A NOCTURNAL RADIATIONAL INVERSION HAVE ALLOWED
TEMPERATURES TO PLUNGE INTO THE UPPER 50S.
INCREASING LIFT ON THE 300K THETA SURFACE JUST AHEAD OF A
PSEUDO-WARM FRONT MOVING IN FROM THE SOUTH CAROLINA COAST THIS
MORNING SHOULD CREATE AT LEAST A FEW HOURS OF LIGHT TO MODERATE
SHOWERS...MOST STRONGLY AFFECTING THE CORRIDOR FROM GEORGETOWN AND
KINGSTREE UP THROUGH MARION...FLORENCE...DILLON AND BENNETTSVILLE
THROUGH EARLY THIS AFTERNOON. ALTHOUGH MOST OF THESE AREAS WILL SEE
MEASURABLE RAINFALL WE ANTICIPATE ACTUAL RAINFALL AMOUNTS TO REMAIN
LESS THAN TWO-TENTHS OF AN INCH. CHANCES FOR RAIN FALL TO LESS THAN
50-50 FOR MYRTLE BEACH...WHITEVILLE AND ELIZABETHTOWN. EVEN FARTHER
EAST IN THE WILMINGTON AREA IT SHOULD REMAIN DRY TODAY WITH THE
DEEPER MOISTURE AND LIFT REMAINING TOO FAR INLAND. THE CLOUD AND
PRECIPITATION PATTERN WILL STRONGLY INFLUENCE HIGH TEMPERATURES
TODAY WITH THE WARMEST READINGS (UPPER 70S) EXPECTED JUST INLAND
FROM THE COAST NEAR WILMINGTON. MID 70S SHOULD PREVAIL FARTHER
INLAND...AND IT`S NOT IMPOSSIBLE FOR HIGHS TO REMAIN EVEN A LITTLE
COOLER THAN THAT IF DENSE CLOUDS AND SHOWERS LINGER ON BEYOND 2-3 PM.
THERE SHOULD BE A LULL IN THE COVERAGE OF PRECIPITATION ACROSS THE
EASTERN CAROLINAS LATE THIS AFTERNOON INTO THE EVENING HOURS.
REDEVELOPMENT OF SHOWERS IS THEN EXPECTED LATE ACROSS THE PEE DEE
REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL WATERS.
ALTHOUGH FORECAST SOUNDINGS SHOW NO INVERSION LAYERS ALOFT TO
INHIBIT CONVECTION...ENVIRONMENTAL LAPSE RATES NEAR MOIST ADIABATIC
WILL NOT PROMOTE DEEP CONVECTION UNTIL BETTER SYNOPTIC FORCING
ARRIVES ON MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...A WET SHORT TERM ON TAP AS A SLOW MOVING LOW
PRESSURE SYSTEM BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE
EASTERN CAROLINAS.
STILL UNCERTAINTY IN TIMING...BUT EXPECT SHOWERS TO BE ONGOING AT
THE START OF THE PERIOD...ESPECIALLY ACROSS THE WESTERN HALF OF THE
ILM CWA...AND BE IMPACTING THE ENTIRE AREA BY MONDAY AFTN. THESE
SHOWERS ARE DUE TO THE ADVANCE OF A SLOWLY MOVING LOW PRESSURE
SYSTEM SPAWNED BY IMPULSES ROTATING DOWN A DEEP...POSITIVELY TILTED
UPPER TROUGH DROPPING OUT OF THE MIDWEST. THE FIRST OF THESE
IMPULSES PUSHES INTO NEW ENGLAND LATE MONDAY AND TRAILS A COLD FRONT
INTO THE REGION. THIS FRONT GETS VERY LITTLE PUSH DUE TO THE
ORIENTATION OF UPPER FEATURES...AND BECOMES STALLED SOMEWHERE ACROSS
THE EASTERN MID-ATLANTIC AND SOUTHEAST. THIS BOUNDARY ACTS A
FOCUSING MECHANISM FOR CONTINUED ROUNDS OF HEAVY RAINFALL AND
THUNDERSTORMS THROUGH TUESDAY.
THE HEAVIEST RAINFALL WILL OCCUR MONDAY AFTN THROUGH TUESDAY
MORNING. THE COMBINATION OF SOME ENHANCED UPPER DIFLUENCE...PWATS
APPROACHING 1.75 INCHES (NEARLY 2 STD DEVIATIONS ABOVE
NORMAL)...RICH THETA-E AIR...10000 FT OF WARM CLOUD DEPTH...AND
CONVERGENCE ALONG THE STALLED BOUNDARY ALL POINT TOWARDS
WIDESPREAD SHOWERS/THUNDERSTORMS WITH HEAVY RAIN. ALTHOUGH BEST
MOISTURE TRANSPORT IS FOCUSED JUST NORTH OF THE ILM CWA...ENHANCED
MOIST ADVECTION FROM SE FLOW OFF THE GULF STREAM SHOULD PROVIDE
SOME HEAVIER RAIN. WILL BUMP POP TO CATEGORICAL MONDAY
AFTN/NIGHT...FALLING TO CHC BY TUE AFTN...WITH TOTAL QPF ABOVE 1
INCH POSSIBLE. WILL NOTE THAT ISOLATED HEAVIER TOTALS ARE
DEFINITELY POSSIBLE...SINCE DEEP SOUTHERLY FLOW BECOMES BOUNDARY
PERPENDICULAR...WHICH FAVORS TRAINING ECHOES FROM SOUTH TO NORTH
AS THE FRONT MAKES VERY LITTLE PROGRESS EASTWARD. SPC DOES HAVE
THE AREA IN A "SEE TEXT" FOR MONDAY...AND DECENT INSTABILITY WILL
EXIST AHEAD OF THE FRONT...BUT OTRW SEVERE PARAMETERS LOOK QUITE
WEAK AND EXPECT MORE OF A HEAVY RAIN THREAT THAN A SEVERE THREAT.
TEMPS WILL BE BELOW CLIMO MONDAY DUE TO CLOUDS AND RAIN...IN THE
UPPER 70S...WITH LOWS WELL ABOVE CLIMO ONLY FALLING INTO THE MID
60S. SIMILAR ON TUESDAY WITH CONTINUED CLOUDS AND SHOWERS...KEEPING
MAX TEMPS JUST BELOW CLIMO AROUND 80 AND MINS ONCE AGAIN FALLING
ONLY INTO THE LOW/MID 60S AT NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...NEARLY STATIONARY FRONT WILL STILL BE OVER THE
AREA EARLY WEDNESDAY AS DEEP UPPER TROUGH AXIS MOVES OVERHEAD. THIS
WILL PROVIDE THE IMPETUS FOR CONTINUED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTNS OF WED AND THU. THE
KICKER NORTHERN STREAM S/W THEN DROPS SOUTHWARD OUT OF CANADA AND
FINALLY PUSHES THE COLD FRONT OFFSHORE THURSDAY. THIS ALLOWS THE
COLUMN TO BEGIN TO DRY OUT WITH SOME WEAK SUBSIDENCE BEHIND THE
DEPARTING TROUGH...BUT DIURNAL SHOWERS ARE STILL POSSIBLE FRI/SAT.
WILL CARRY CHC POP WED/THU WITH SCHC FRI/SAT...BUT THE ACTIVITY
FRI/SAT SHOULD BE MUCH MORE ISOLATED IN COVERAGE.
BOTH GFS AND EURO DEPICT THE UPPER TROUGH CUTTING OFF NEAR 70 WEST
AND SPAWNING A HYBRID-TYPE SURFACE LOW WELL OFFSHORE. THIS IS
FURTHER EAST THAN PREVIOUS RUNS AND MEANS LESS OF A RAIN CHANCE FOR
THE WKND THAN EARLIER GUIDANCE HAD SUGGESTED. FEEL NO REASON TO
CHANGE INHERITED SCHC ATTM.
TEMPS WILL REMAIN FAIRLY UNIFORM THROUGH THE EXTENDED...WITH HIGHS A
DEGREE OR SO BELOW CLIMO AND MINS AT NIGHT A DEGREE OR TWO ABOVE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...SHOWERS MOVING ONSHORE NEAR MYR WILL PRODUCE AT LEAST
MVFR CONDITIONS AT MYR/CRE THROUGH 14-16Z. THE CHANCE OF IFR
CONDITIONS IS LOW...BUT IF IT DOES OCCUR IT WOULD BE VERY BRIEF AND
ASSOCIATED WITH THE ISOLATED MODERATE SHOWERS AT MYR/CRE. THIS
SHOWER ACTIVITY WILL BE MOVING FURTHER INLAND ON SOUTHEASTERLY WINDS
STAYING EAST OF...BUT EVENTUALLY AFFECTING THE LBT TERMINAL BY 14Z
WITH THE CHANCE OF AT LEAST TEMPO MVFR CONDITIONS. THROUGH THIS
AFTERNOON THE BEST CHANCE OF SHOWERS/MVFR CONDITIONS WILL BE AT THE
FLO/LBT TERMINALS WITH LESSER CHANCES OF PRECIPITATION AND HIGHER
CHANCES OF VFR AT THE COASTAL TERMINALS. BUT BY LATE AFTERNOON THE
BEST CHANCE OF PRECIPITATION/MVFR CONDITIONS WILL SHIFT TO THE
COASTAL TERMINALS BEFORE BECOMING VERY ISOLATED OR ENDING
ALL-TOGETHER DURING THE EVENING AS SIGNIFICANT LIFT DECREASES.
THROUGH THE REMAINDER OF THE TAF VALID PERIOD PERIODS OF MVFR CAN BE
EXPECTED. THE CHANCE OF IFR IS LOW.
EXTENDED OUTLOOK...UNSETTLED WEATHER MONDAY THROUGH THE PERIOD WITH
A GOOD CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM SUNDAY...SHOWERS ALONG THE SC COAST WILL CONTINUE
THROUGH MUCH OF THE MORNING AND IN A MORE LIMITED EXTENT INTO THE
EARLY AFTERNOON AS WELL. LATEST OBSERVATIONS SHOW SEAS JUST A TOUCH
HIGHER THAN EARLIER FORECAST...OTHERWISE THIS EARLY MORNING UPDATE
CONTAINS FEW OTHER SIGNIFICANT CHANGES. PREVIOUS DISCUSSION FROM 3
AM FOLLOWS...
HIGH PRESSURE WELL OFFSHORE IS PROVIDING A MODEST SOUTHEAST WIND
ACROSS THE COASTAL WATERS THIS MORNING. LOW PRESSURE DEVELOPING OVER
MISSISSIPPI WILL MOVE TO NEAR CHATTANOOGA TENNESSEE BY LATE
TONIGHT...VEERING OUR WINDS MORE SOUTHERLY WITH A SLIGHT INCREASE IN
WIND SPEEDS EXPECTED. ALTHOUGH THERE ARE NO IDENTIFIABLE FRONTS
ACROSS THE AREA CURRENTLY SHOWERS DEVELOPING ALONG THE SOUTH
CAROLINA COAST THIS MORNING SOUTH OF MYRTLE BEACH ARE ASSOCIATED
WITH A WARM FRONTAL-LIKE STRUCTURE THAT WILL LIFT NORTHWESTWARD AND
INLAND THIS MORNING. THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN
ACROSS THE SC WATERS THIS MORNING...BECOMING MORE ISOLATED IN NATURE
THIS AFTERNOON. MODELS SHOW REDEVELOPMENT OF SHOWERS POSSIBLE LATE
TONIGHT.
WITH ONSHORE WINDS CONTINUING WE EXPECT A VERY GRADUAL INCREASE IN
SEA HEIGHTS THROUGH TONIGHT. BUOYS SHOW SEAS ARE CURRENTLY 2 FT NEAR
SHORE AND 3 FT OUT AT THE FRYING PAN SHOALS BUOY. THESE SEA HEIGHTS
SHOULD BUILD BY ABOUT ONE FOOT BY LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...THE WATERS WILL BE SANDWICHED BETWEEN A VERY
SLOWLY ADVANCING COLD FRONT FROM THE WEST...AND HIGH PRESSURE
RETREATING TO THE EAST...THROUGH THE SHORT TERM. THIS CREATES
SOUTHERLY WINDS MONDAY...VEERING SLIGHTLY TO THE SW TUESDAY AS FRONT
GETS CLOSER TO THE AREA...AT 10-15 KTS THROUGHOUT. ALTHOUGH A WEAK
1FT/11SEC EASTERLY SWELL WILL EXIST IN THE WAVE SPECTRUM...THE
SIGNIFICANT WAVE HEIGHTS WILL BE FORCED PRIMARILY BY THE WIND...WITH
3-5 FT SEAS MONDAY FALLING TO 3-4 FT TUESDAY. ADDITIONALLY...THERE
IS A GOOD CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN TO IMPACT THE WATERS LATE MONDAY AND TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
646 AM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM SUNDAY...RADAR SHOWS THE BAND OF SHOWERS ALONG THE SC
COAST IS DEVELOPING ABOUT 30-40 MILES FARTHER EAST THAN WAS
EXPECTED. THE 06Z NAM WAS EVEN WORSE THAN THE 00Z RUN WITH THIS
ACTIVITY. THE LACK OF RECENT HRRR MODEL DATA DUE TO SUPERCOMPUTER
PROBLEMS AT NCEP LEAVES US WITH LINEAR EXTRAPOLATION AS OUR BEST
WEAPON THIS MORNING. WE`RE FORECASTING THE CURRENT ACTIVITY TO
CONTINUE STREAMING NORTH-NORTHWEST ACROSS MYRTLE BEACH AND CONWAY
INTO MARION...DILLON AND EVENTUALLY LUMBERTON. SHOWERS WILL PROBABLY
DEVELOP WEST OF THE MAIN AXIS ACROSS THE SC PEE DEE REGION AS
WELL...BUT WITH AREAL COVERAGE ONLY IN THE 40-50 PERCENT RANGE. DRY
AIR IN THE CAPE FEAR REGION SHOULD INSULATE WILMINGTON FROM RAINFALL
TODAY. OTHERWISE THE SYNOPTIC REASONING GIVEN EARLIER IS STILL VALID
ONCE THE SPATIAL ADJUSTMENT TO THE EAST IS MADE. PREVIOUS DISCUSSION
FROM 3 AM FOLLOWS...
HIGH PRESSURE WELL TO OUR EAST AND LOW PRESSURE DEVELOPING OVER
MISSISSIPPI ARE CREATING A SOUTHEAST SURFACE FLOW ACROSS THE COASTAL
CAROLINAS. THIS WARM ONSHORE WIND HAS SO FAR HELD TEMPERATURES AT
THE BEACHES IN THE 70S...WHILE JUST A FEW MILES INLAND CALM SURFACE
WINDS WITHIN A NOCTURNAL RADIATIONAL INVERSION HAVE ALLOWED
TEMPERATURES TO PLUNGE INTO THE UPPER 50S.
INCREASING LIFT ON THE 300K THETA SURFACE JUST AHEAD OF A
PSEUDO-WARM FRONT MOVING IN FROM THE SOUTH CAROLINA COAST THIS
MORNING SHOULD CREATE AT LEAST A FEW HOURS OF LIGHT TO MODERATE
SHOWERS...MOST STRONGLY AFFECTING THE CORRIDOR FROM GEORGETOWN AND
KINGSTREE UP THROUGH MARION...FLORENCE...DILLON AND BENNETTSVILLE
THROUGH EARLY THIS AFTERNOON. ALTHOUGH MOST OF THESE AREAS WILL SEE
MEASURABLE RAINFALL WE ANTICIPATE ACTUAL RAINFALL AMOUNTS TO REMAIN
LESS THAN TWO-TENTHS OF AN INCH. CHANCES FOR RAIN FALL TO LESS THAN
50-50 FOR MYRTLE BEACH...WHITEVILLE AND ELIZABETHTOWN. EVEN FARTHER
EAST IN THE WILMINGTON AREA IT SHOULD REMAIN DRY TODAY WITH THE
DEEPER MOISTURE AND LIFT REMAINING TOO FAR INLAND. THE CLOUD AND
PRECIPITATION PATTERN WILL STRONGLY INFLUENCE HIGH TEMPERATURES
TODAY WITH THE WARMEST READINGS (UPPER 70S) EXPECTED JUST INLAND
FROM THE COAST NEAR WILMINGTON. MID 70S SHOULD PREVAIL FARTHER
INLAND...AND IT`S NOT IMPOSSIBLE FOR HIGHS TO REMAIN EVEN A LITTLE
COOLER THAN THAT IF DENSE CLOUDS AND SHOWERS LINGER ON BEYOND 2-3 PM.
THERE SHOULD BE A LULL IN THE COVERAGE OF PRECIPITATION ACROSS THE
EASTERN CAROLINAS LATE THIS AFTERNOON INTO THE EVENING HOURS.
REDEVELOPMENT OF SHOWERS IS THEN EXPECTED LATE ACROSS THE PEE DEE
REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL WATERS.
ALTHOUGH FORECAST SOUNDINGS SHOW NO INVERSION LAYERS ALOFT TO
INHIBIT CONVECTION...ENVIRONMENTAL LAPSE RATES NEAR MOIST ADIABATIC
WILL NOT PROMOTE DEEP CONVECTION UNTIL BETTER SYNOPTIC FORCING
ARRIVES ON MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...A WET SHORT TERM ON TAP AS A SLOW MOVING LOW
PRESSURE SYSTEM BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE
EASTERN CAROLINAS.
STILL UNCERTAINTY IN TIMING...BUT EXPECT SHOWERS TO BE ONGOING AT
THE START OF THE PERIOD...ESPECIALLY ACROSS THE WESTERN HALF OF THE
ILM CWA...AND BE IMPACTING THE ENTIRE AREA BY MONDAY AFTN. THESE
SHOWERS ARE DUE TO THE ADVANCE OF A SLOWLY MOVING LOW PRESSURE
SYSTEM SPAWNED BY IMPULSES ROTATING DOWN A DEEP...POSITIVELY TILTED
UPPER TROUGH DROPPING OUT OF THE MIDWEST. THE FIRST OF THESE
IMPULSES PUSHES INTO NEW ENGLAND LATE MONDAY AND TRAILS A COLD FRONT
INTO THE REGION. THIS FRONT GETS VERY LITTLE PUSH DUE TO THE
ORIENTATION OF UPPER FEATURES...AND BECOMES STALLED SOMEWHERE ACROSS
THE EASTERN MID-ATLANTIC AND SOUTHEAST. THIS BOUNDARY ACTS A
FOCUSING MECHANISM FOR CONTINUED ROUNDS OF HEAVY RAINFALL AND
THUNDERSTORMS THROUGH TUESDAY.
THE HEAVIEST RAINFALL WILL OCCUR MONDAY AFTN THROUGH TUESDAY
MORNING. THE COMBINATION OF SOME ENHANCED UPPER DIFFLUENCE...PWATS
APPROACHING 1.75 INCHES (NEARLY 2 SD`S ABOVE NORMAL)...RICH THETA-E
AIR...10000 FT OF WARM CLOUD DEPTH...AND CONVERGENCE ALONG THE
STALLED BOUNDARY ALL POINT TOWARDS WIDESPREAD SHOWERS/THUNDERSTORMS
WITH HEAVY RAIN. ALTHOUGH BEST MOISTURE TRANSPORT IS FOCUSED JUST
NORTH OF THE ILM CWA...ENHANCED MOIST ADVECTION FROM SE FLOW OFF THE
GULF STREAM SHOULD PROVIDE SOME HEAVIER RAIN. WILL BUMP POP TO
CATEGORICAL MONDAY AFTN/NIGHT...FALLING TO CHC BY TUE AFTN...WITH
TOTAL QPF ABOVE 1 INCH POSSIBLE. WILL NOTE THAT ISOLATED HEAVIER
TOTALS ARE DEFINITELY POSSIBLE...SINCE DEEP SOUTHERLY FLOW BECOMES
BOUNDARY PERPENDICULAR...WHICH FAVORS TRAINING ECHOES FROM SOUTH TO
NORTH AS THE FRONT MAKES VERY LITTLE PROGRESS EASTWARD. SPC DOES
HAVE THE AREA IN A "SEE TEXT" FOR MONDAY...AND DECENT INSTABILITY
WILL EXIST AHEAD OF THE FRONT...BUT OTRW SEVERE PARAMETERS LOOK
QUITE WEAK AND EXPECT MORE OF A HEAVY RAIN THREAT THAN A SEVERE
THREAT.
TEMPS WILL BE BELOW CLIMO MONDAY DUE TO CLOUDS AND RAIN...IN THE
UPPER 70S...WITH LOWS WELL ABOVE CLIMO ONLY FALLING INTO THE MID
60S. SIMILAR ON TUESDAY WITH CONTINUED CLOUDS AND SHOWERS...KEEPING
MAX TEMPS JUST BELOW CLIMO AROUND 80 AND MINS ONCE AGAIN FALLING
ONLY INTO THE LOW/MID 60S AT NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...NEARLY STATIONARY FRONT WILL STILL BE OVER THE
AREA EARLY WEDNESDAY AS DEEP UPPER TROUGH AXIS MOVES OVERHEAD. THIS
WILL PROVIDE THE IMPETUS FOR CONTINUED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTNS OF WED AND THU. THE
KICKER NORTHERN STREAM S/W THEN DROPS SOUTHWARD OUT OF CANADA AND
FINALLY PUSHES THE COLD FRONT OFFSHORE THURSDAY. THIS ALLOWS THE
COLUMN TO BEGIN TO DRY OUT WITH SOME WEAK SUBSIDENCE BEHIND THE
DEPARTING TROUGH...BUT DIURNAL SHOWERS ARE STILL POSSIBLE FRI/SAT.
WILL CARRY CHC POP WED/THU WITH SCHC FRI/SAT...BUT THE ACTIVITY
FRI/SAT SHOULD BE MUCH MORE ISOLATED IN COVERAGE.
BOTH GFS AND EURO DEPICT THE UPPER TROUGH CUTTING OFF NEAR 70 WEST
AND SPAWNING A HYBRID-TYPE SURFACE LOW WELL OFFSHORE. THIS IS
FURTHER EAST THAN PREVIOUS RUNS AND MEANS LESS OF A RAIN CHANCE FOR
THE WKND THAN EARLIER GUIDANCE HAD SUGGESTED. FEEL NO REASON TO
CHANGE INHERITED SCHC ATTM.
TEMPS WILL REMAIN FAIRLY UNIFORM THROUGH THE EXTENDED...WITH HIGHS A
DEGREE OR SO BELOW CLIMO AND MINS AT NIGHT A DEGREE OR TWO ABOVE.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...EXPECT VFR TO PREVAIL THROUGH THE PERIOD WITH CLOUD
COVER INCREASING IMMENSELY DURING THE MORNING HOURS.
CURRENT SATELLITE IMAGERY CONTINUES TO SHOW HIGH LEVEL CLOUDS WITH
INTERVALS OF MID LEVEL CLOUDS SLOWLY MOVING INTO THE REGION AS LOW
PRESSURE OVER THE GULF OF MEXICO PROGRESSES CLOSER TO THE EASTERN
SEABOARD. ANTICIPATE SKY COVERAGE TO BECOME BKN/OVC THROUGH THE
OVERNIGHT HOURS WITH SOUTHEAST SFC WINDS AOB 5 KTS. THOUGH LOW LEVEL
MOISTURE IS INCREASING AND SFC WINDS ARE LIGHT...ANTICIPATE CLOUD
COVER AND SLIGHTLY STRONGER WINDS AT THE TOP OF THE BOUNDARY LAYER
TO INHIBIT ANY FOG DEVELOPMENT. AFTER DAYBREAK...LOW-END VFR CIGS
WILL SLOWLY BEGIN TO FILL IN...EVENTUALLY BECOMING BKN BY EARLY
AFTERNOON. SOUTH-SOUTHEAST WINDS WILL INCR TO 10G20KT...SUBSIDING
AFTER SUNSET. RAIN CHANCES WILL INCREASE FROM WEST TO EAST BEGINNING
LATER THIS MORNING AND CONTINUING THROUGH THE PERIOD...WITH
-RA/SHRA. FOR NOW HAVE INTRODUCED VCSH AT ALL SITES...WITH -RA AT
THE INLAND SITES TOWARD THE EVENING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER MONDAY THROUGH THE PERIOD WITH
A GOOD CHANCE FOR PRECIPITATION EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM SUNDAY...SHOWERS ALONG THE SC COAST WILL CONTINUE
THROUGH MUCH OF THE MORNING AND IN A MORE LIMITED EXTENT INTO THE
EARLY AFTERNOON AS WELL. LATEST OBSERVATIONS SHOW SEAS JUST A TOUCH
HIGHER THAN EARLIER FORECAST...OTHERWISE THIS EARLY MORNING UPDATE
CONTAINS FEW OTHER SIGNIFICANT CHANGES. PREVIOUS DISCUSSION FROM 3
AM FOLLOWS...
HIGH PRESSURE WELL OFFSHORE IS PROVIDING A MODEST SOUTHEAST WIND
ACROSS THE COASTAL WATERS THIS MORNING. LOW PRESSURE DEVELOPING OVER
MISSISSIPPI WILL MOVE TO NEAR CHATTANOOGA TENNESSEE BY LATE
TONIGHT...VEERING OUR WINDS MORE SOUTHERLY WITH A SLIGHT INCREASE IN
WIND SPEEDS EXPECTED. ALTHOUGH THERE ARE NO IDENTIFIABLE FRONTS
ACROSS THE AREA CURRENTLY SHOWERS DEVELOPING ALONG THE SOUTH
CAROLINA COAST THIS MORNING SOUTH OF MYRTLE BEACH ARE ASSOCIATED
WITH A WARM FRONTAL-LIKE STRUCTURE THAT WILL LIFT NORTHWESTWARD AND
INLAND THIS MORNING. THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN
ACROSS THE SC WATERS THIS MORNING...BECOMING MORE ISOLATED IN NATURE
THIS AFTERNOON. MODELS SHOW REDEVELOPMENT OF SHOWERS POSSIBLE LATE
TONIGHT.
WITH ONSHORE WINDS CONTINUING WE EXPECT A VERY GRADUAL INCREASE IN
SEA HEIGHTS THROUGH TONIGHT. BUOYS SHOW SEAS ARE CURRENTLY 2 FT NEAR
SHORE AND 3 FT OUT AT THE FRYING PAN SHOALS BUOY. THESE SEA HEIGHTS
SHOULD BUILD BY ABOUT ONE FOOT BY LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...THE WATERS WILL BE SANDWICHED BETWEEN A VERY
SLOWLY ADVANCING COLD FRONT FROM THE WEST...AND HIGH PRESSURE
RETREATING TO THE EAST...THROUGH THE SHORT TERM. THIS CREATES
SOUTHERLY WINDS MONDAY...VEERING SLIGHTLY TO THE SW TUESDAY AS FRONT
GETS CLOSER TO THE AREA...AT 10-15 KTS THROUGHOUT. ALTHOUGH A WEAK
1FT/11SEC EASTERLY SWELL WILL EXIST IN THE WAVE SPECTRUM...THE
SIGNIFICANT WAVE HEIGHTS WILL BE FORCED PRIMARILY BY THE WIND...WITH
3-5 FT SEAS MONDAY FALLING TO 3-4 FT TUESDAY. ADDITIONALLY...THERE
IS A GOOD CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN TO IMPACT THE WATERS LATE MONDAY AND TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...TRA
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
938 AM EDT SUN MAY 13 2012
.SYNOPSIS...
LOW PRESSURE OVER MISSISSIPPI WILL MOVE SLOWLY NORTHEAST INTO THE
CENTRAL APPALACHIANS BY MONDAY EVENING. THIS LOW WILL MOVE OFF THE
MID ATLANTIC COAST BY WEDNESDAY MORNING. HIGH PRESSURE BUILDS IN
OVER THE REGION THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 920 PM EDT SUNDAY...
THIS MORNING RNK 12Z/8AM SOUNDING SHOWED PLENTY OF MOISTURE WITH A
PWAT AT 0.98 INCHES WITH A S-SE FLOW UP TO 750 MB. REGIONAL
WSR-88D IMAGES DISPLAYED NUMEROUS SHOWERS LIFTING NORTHEAST ACROSS
THE OHIO AND TENNESSEE VALLEYS. MADE SOME MINOR ADJUSTMENTS IN
CLOUD COVER...POPS AND QPF FOR TODAY. LEANED TOWARDS THE WRFARW-RNK
FOR POPS INTO THIS AFTERNOON. FLASH FLOOD WATCH FOR THIS EVENING
LOOK ON TRACK. PLAN TO REVIEW TRENDS AND 12Z RUN OF MODELS FOR ANY
ADJUSTMENTS.
AS OF 425 AM EDT SUNDAY...
WIDESPREAD SHOWERS OVER THE OHIO AND TENNESSEE VALLEYS EARLY THIS
MORNING WILL MOVE EAST TODAY. LOCAL WRF AND THE 00Z SREF HAVE THE
PRECIPITATION REACHING THE WESTERN EDGE OF THE COUNTY WARNING AREA
BETWEEN 14-18Z/10AM-2PM AND SPREADING ACROSS THE REST OF THE
FORECAST AREA BY 8PM/00Z. STARTING OUT WITH TEMPERATURES IN THE
MID 50S TO LOWER 60S THIS MORNING. CLOUDS WILL BE SPREAD IN BUT
THERE WILL STILL BE ENOUGH SUN TO BRING TEMPERATURES INTO THE 70S
EAST OF THE BLUE RIDGE. OVERALL COOLED MAXIMUM TEMPERATURES A
COUPLE OF DEGREES FOR TODAY.
TONIGHT...IMPRESSIVE LIFT WITH THE MODELS SHOWING STRONG UPPER
DIVERGENCE OVER THE FORECAST AND STRONG ISENTROPIC LIFT IN THE 295
TO 305K LAYER BETWEEN 06Z-12Z/2AM-8AM. SOUTHEAST WINDS AT THE
SURFACE UP THROUGH THE 850 MB SOUTHERLY WINDS THAT INCREASE TO
AROUND 35 KNOTS LATE TONIGHT WILL BE ADVECTING IN 1.5 INCH
PRECIPITABLE WATER VALUES. KEPT IN MENTION OF HEAVY RAINFALL
DURING THIS TIME FRAME. ONLY MINOR CHANGES MADE TO OVERNIGHT LOWS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
HEAVY RAIN IS EXPECTED TO BE ONGOING BY SUNRISE MONDAY AS LARGE
AMOUNTS OF GULF MOISTURE MOVE IN AHEAD OF A SLOW MOVING COLD FRONT
TO OUR WEST...WHILE A SERIES OF UPPER LEVEL DISTURBANCES PASS ACROSS
OUR AREA FROM THE SOUTHWEST...TRIGGERING THE HEAVY SHOWER ACTIVITY.
THE PRIMARY CONCERN FOR MONDAY WILL BE THE POSSIBILITY OF FLASH
FLOODING...MAINLY IN THE FOOTHILLS OF THE BLUE RIDGE...BUT ALSO IN
AREAS WERE HEAVY SHOWERS AND THUNDERSTORMS DEVELOP REPEATEDLY OVER
THE SAME LOCATIONS. WILL ALSO HAVE TO KEEP AN EYE ON THE RIVERS
ACROSS OUR AREA AS MULTIPLE WAVES OF HEAVY RAIN MAY PUSH SOME OF
THESE WATERWAYS UP INTO MINOR FLOOD.
THICK CLOUD COVER AND RAIN WILL ALSO KEEP A LID ON DAYTIME HEATING
ON MONDAY...AND EXPECT AFTERNOON HIGHS TO HOLD IN THE MID AND UPPER
60S FOR MUCH OF THE AREA...AND THIS FORECAST MAY BE A LITTLE TOO
OPTIMISTIC IN SOME AREAS. BY MONDAY EVENING...THE HEAVIEST RAIN IS
EXPECTED TO SHIFT OVER THE PIEDMONT AS THE AXIS OF THE MAIN UPPER
LEVEL TROUGH MOVES EAST...WHILE ONLY SCATTERED LIGHT SHOWERS REMAIN
ACROSS THE MOUNTAINS.
THE COLD FRONT WILL CONTINUE TO PUSH THROUGH OUR AREA DURING THE
PREDAWN HOURS OF TUESDAY MORNING...AND IS EXPECTED TO BE SITUATED
ALONG THE BLUE RIDGE BY SUNRISE. SHOWER ACTIVITY...AND ISOLATED
THUNDERSTORMS...WILL INCREASE IN COVERAGE BY AFTERNOON AS DAYTIME
HEATING INCREASES...BUT BELIEVE BY THIS POINT THAT THE ORGANIZED
HEAVY RAIN WILL BE OUT OF OUR AREA TO THE EAST. THE COLD FRONT IS
EXPECTED TO EXIT OUR AREA BY MID AFTERNOON...WITH HIGH PRESSURE
BUILDING IN FROM THE WEST.
WITH LESS RAINFALL TO CONTEND WITH AND DRIER AIR TRYING TO WORK ITS
WAY INTO THE AREA...TUESDAY AFTERNOON HIGH TEMPERATURES ARE EXPECTED
TO REBOUND SLIGHTLY...WITH HIGHS RANGING FROM THE UPPER 60S ACROSS
THE MOUNTAINS...TO THE LOW TO MID 70S ACROSS THE PIEDMONT. TUESDAY
NIGHT LOWS WILL RANGE FROM THE LOW 50S WEST...TO THE UPPER 50S EAST.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 1245 PM EDT SATURDAY...
FRONTAL BOUNDARY FINALLY SLIDES FAR ENOUGH EAST WEDNESDAY TO
ALLOW CLEARING/DRYING TO TAKE PLACE...WITH SLIGHT CHANCES OF
LINGERING SHOWERS ACROSS THE NORTH CAROLINA MOUNTAINS INTO THE
PIEDMONT.
BUBBLE OF HIGH PRESSURE WILL MOVE FROM THE GREAT LAKES INTO THE
MIDDLE ATLANTIC THURSDAY INTO FRIDAY WITH DRY AND SEASONAL WEATHER
EXPECTED.
THE MODELS ARE VARYING ON SOLUTIONS TO THE WEATHER PATTERN NEXT
WEEKEND...ALTHOUGH ENOUGH CONSENSUS SHOWS DEVELOPING LOW OFF THE
SOUTHEAST COAST STAYING WELL ENOUGH AWAY FROM US TO KEEP OUR REGION
DRY. PERHAPS A WEDGE COULD FORM PER HIGH PRESSURE ACROSS THE MID
ATLANTIC BUT OVERALL SKY COVER SHOULD BE PARTLY SUNNY NEXT SATURDAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AS OF 735 AM EDT SUNDAY...
HIGH CLOUDS COVERED THE MOUNTAINS AND WERE SPREADING EAST THIS
MORNING. CEILINGS WILL LOWER THROUGHOUT THE DAY AS PRECIPITATION
SPREADS FROM WEST TO EAST ACROSS THE FORECAST AREA. USED THE LOCAL
WRF AND RUC MODELS FOR THE ARRIVAL TIME OF THE SHOWERS. BY THIS
AFTERNOON CEILINGS WILL DROP TO MVFR AS THE EXTENSIVE
PRECIPITATION MOVES INTO THE AREA.
HIGH CONFIDENCE THAT CEILINGS WILL BE MVFR TO IFR OVERNIGHT. HAVE
BLF/LWB AND BCB LOWERING TO IFR SHORTLY AFTER 00Z/8PM THIS EVENING
WITH ROA AND LYH BECOMING IFR BY 06Z.
BY MONDAY EVENING THE LOW COMING OUT OF MISSISSIPPI WILL REACH
THE CENTRAL APPALACHIANS. THIS WILL PROLONG IFR CONDITIONS INTO MONDAY
NIGHT IN ASSOCIATION WITH AN AXIS OF HEAVIER RAINFALL.
DRIER AIR SHOULD FINALLY WORK IN TUESDAY NIGHT INTO WEDNESDAY
BRINGING A RETURN TO OVERALL VFR..ASIDE FROM ISOLATED SHOWERS
WEDNESDAY INTO THURSDAY.
&&
.HYDROLOGY...
AS OF 420 AM EDT SUNDAY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS ALONG AND ON EACH SIDE
OF THE BLUE RIDGE FROM ROANOKE THROUGH NORTHWEST NORTH CAROLINA.
SOUTHERN APPALACHIANS IS MENTIONED IN THE HPC EXCESSIVE RAINFALL
OUTLOOK AND 48 RAIN TOTALS MAY BE 2.5 TO 3.5 INCHES...WITH THE
HEAVIER AMOUNTS ON THE EAST SLOPES OF THE BLUE RIDGE. EVENT MAY
EVENTUALLY TRANSITION INTO AN AREAL FLOOD THREAT AND POSSIBLY RIVER
FLOODING...OF COURSE DEPENDING ON THE AMOUNT OF RAIN...BUT FOR NOW
FLASH FLOODING LOOKS TO BE THE MAIN THREAT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH FROM 9 PM EDT THIS EVENING THROUGH TUESDAY
EVENING FOR VAZ009-012>017-022-032-033-043.
NC...FLASH FLOOD WATCH FROM 9 PM EDT THIS EVENING THROUGH TUESDAY
EVENING FOR NCZ001>004-018>020.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...NF
LONG TERM...WP
AVIATION...AMS/JH
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
738 AM EDT SUN MAY 13 2012
.SYNOPSIS...
LOW PRESSURE OVER MISSISSIPPI WILL MOVE SLOWLY NORTHEAST INTO THE
CENTRAL APPALACHIANS BY MONDAY EVENING. THIS LOW WILL MOVE OFF THE
MID ATLANTIC COAST BY WEDNESDAY MORNING. HIGH PRESSURE BUILDS IN
OVER THE REGION THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 425 AM EDT SUNDAY...
WIDESPREAD SHOWERS OVER THE OHIO AND TENNESSEE VALLEYS EARLY THIS
MORNING WILL MOVE EAST TODAY. LOCAL WRF AND THE 00Z SREF HAVE THE
PRECIPITATION REACHING THE WESTERN EDGE OF THE COUNTY WARNING AREA
BETWEEN 14-18Z/10AM-2PM AND SPREADING ACROSS THE REST OF THE
FORECAST AREA BY 8PM/00Z. STARTING OUT WITH TEMPERATURES IN THE
MID 50S TO LOWER 60S THIS MORNING. CLOUDS WILL BE SPREAD IN BUT
THERE WILL STILL BE ENOUGH SUN TO BRING TEMPERATURES INTO THE 70S
EAST OF THE BLUE RIDGE. OVERALL COOLED MAXIMUM TEMPERATURES A
COUPLE OF DEGREES FOR TODAY.
TONIGHT...IMPRESSIVE LIFT WITH THE MODELS SHOWING STRONG UPPER
DIVERGENCE OVER THE FORECAST AND STRONG ISENTROPIC LIFT IN THE 295
TO 305K LAYER BETWEEN 06Z-12Z/2AM-8AM. SOUTHEAST WINDS AT THE
SURFACE UP THROUGH THE 850 MB SOUTHERLY WINDS THAT INCREASE TO
AROUND 35 KNOTS LATE TONIGHT WILL BE ADVECTING IN 1.5 INCH
PRECIPITABLE WATER VALUES. KEPT IN MENTION OF HEAVY RAINFALL
DURING THIS TIME FRAME. ONLY MINOR CHANGES MADE TO OVERNIGHT LOWS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
HEAVY RAIN IS EXPECTED TO BE ONGOING BY SUNRISE MONDAY AS LARGE
AMOUNTS OF GULF MOISTURE MOVE IN AHEAD OF A SLOW MOVING COLD FRONT
TO OUR WEST...WHILE A SERIES OF UPPER LEVEL DISTURBANCES PASS ACROSS
OUR AREA FROM THE SOUTHWEST...TRIGGERING THE HEAVY SHOWER ACTIVITY.
THE PRIMARY CONCERN FOR MONDAY WILL BE THE POSSIBILITY OF FLASH
FLOODING...MAINLY IN THE FOOTHILLS OF THE BLUE RIDGE...BUT ALSO IN
AREAS WERE HEAVY SHOWERS AND THUNDERSTORMS DEVELOP REPEATEDLY OVER
THE SAME LOCATIONS. WILL ALSO HAVE TO KEEP AN EYE ON THE RIVERS
ACROSS OUR AREA AS MULTIPLE WAVES OF HEAVY RAIN MAY PUSH SOME OF
THESE WATERWAYS UP INTO MINOR FLOOD.
THICK CLOUD COVER AND RAIN WILL ALSO KEEP A LID ON DAYTIME HEATING
ON MONDAY...AND EXPECT AFTERNOON HIGHS TO HOLD IN THE MID AND UPPER
60S FOR MUCH OF THE AREA...AND THIS FORECAST MAY BE A LITTLE TOO
OPTIMISTIC IN SOME AREAS. BY MONDAY EVENING...THE HEAVIEST RAIN IS
EXPECTED TO SHIFT OVER THE PIEDMONT AS THE AXIS OF THE MAIN UPPER
LEVEL TROUGH MOVES EAST...WHILE ONLY SCATTERED LIGHT SHOWERS REMAIN
ACROSS THE MOUNTAINS.
THE COLD FRONT WILL CONTINUE TO PUSH THROUGH OUR AREA DURING THE
PREDAWN HOURS OF TUESDAY MORNING...AND IS EXPECTED TO BE SITUATED
ALONG THE BLUE RIDGE BY SUNRISE. SHOWER ACTIVITY...AND ISOLATED
THUNDERSTORMS...WILL INCREASE IN COVERAGE BY AFTERNOON AS DAYTIME
HEATING INCREASES...BUT BELIEVE BY THIS POINT THAT THE ORGANIZED
HEAVY RAIN WILL BE OUT OF OUR AREA TO THE EAST. THE COLD FRONT IS
EXPECTED TO EXIT OUR AREA BY MID AFTERNOON...WITH HIGH PRESSURE
BUILDING IN FROM THE WEST.
WITH LESS RAINFALL TO CONTEND WITH AND DRIER AIR TRYING TO WORK ITS
WAY INTO THE AREA...TUESDAY AFTERNOON HIGH TEMPERATURES ARE EXPECTED
TO REBOUND SLIGHTLY...WITH HIGHS RANGING FROM THE UPPER 60S ACROSS
THE MOUNTAINS...TO THE LOW TO MID 70S ACROSS THE PIEDMONT. TUESDAY
NIGHT LOWS WILL RANGE FROM THE LOW 50S WEST...TO THE UPPER 50S EAST.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 1245 PM EDT SATURDAY...
FRONTAL BOUNDARY FINALLY SLIDES FAR ENOUGH EAST WEDNESDAY TO
ALLOW CLEARING/DRYING TO TAKE PLACE...WITH SLIGHT CHANCES OF
LINGERING SHOWERS ACROSS THE NORTH CAROLINA MOUNTAINS INTO THE
PIEDMONT.
BUBBLE OF HIGH PRESSURE WILL MOVE FROM THE GREAT LAKES INTO THE
MIDDLE ATLANTIC THURSDAY INTO FRIDAY WITH DRY AND SEASONAL WEATHER
EXPECTED.
THE MODELS ARE VARYING ON SOLUTIONS TO THE WEATHER PATTERN NEXT
WEEKEND...ALTHOUGH ENOUGH CONSENSUS SHOWS DEVELOPING LOW OFF THE
SOUTHEAST COAST STAYING WELL ENOUGH AWAY FROM US TO KEEP OUR REGION
DRY. PERHAPS A WEDGE COULD FORM PER HIGH PRESSURE ACROSS THE MID
ATLANTIC BUT OVERALL SKY COVER SHOULD BE PARTLY SUNNY NEXT SATURDAY.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 735 AM EDT SUNDAY...
HIGH CLOUDS COVERED THE MOUNTAINS AND WERE SPREADING EAST THIS
MORNING. CEILINGS WILL LOWER THROUGHOUT THE DAY AS PRECIPITATION
SPREADS FROM WEST TO EAST ACROSS THE FORECAST AREA. USED THE LOCAL
WRF AND RUC MODELS FOR THE ARRIVAL TIME OF THE SHOWERS. BY THIS
AFTERNOON CEILINGS WILL DROP TO MVFR AS THE EXTENSIVE
PRECIPITATION MOVES INTO THE AREA.
HIGH CONFIDENCE THAT CEILINGS WILL BE MVFR TO IFR OVERNIGHT. HAVE
BLF/LWB AND BCB LOWERING TO IFR SHORTLY AFTER 00Z/8PM THIS EVENING
WITH ROA AND LYH BECOMING IFR BY 06Z.
BY MONDAY EVENING THE LOW COMING OUT OF MISSISSIPPI WILL REACH
THE CENTRAL APPALACHIANS. THIS WILL PROLONG IFR CONDITIONS INTO MONDAY
NIGHT IN ASSOCIATION WITH AN AXIS OF HEAVIER RAINFALL.
DRIER AIR SHOULD FINALLY WORK IN TUESDAY NIGHT INTO WEDNESDAY
BRINGING A RETURN TO OVERALL VFR..ASIDE FROM ISOLATED SHOWERS
WEDNESDAY INTO THURSDAY.
&&
.HYDROLOGY...
AS OF 420 AM EDT SUNDAY...
HAVE ISSUED A FLASH FLOOD WATCH FOR AREAS ALONG AND ON EACH SIDE
OF THE BLUE RIDGE FROM ROANOKE THROUGH NORTHWEST NORTH CAROLINA.
SOUTHERN APPALACHIANS IS MENTIONED IN THE HPC EXCESSIVE RAINFALL
OUTLOOK AND 48 RAIN TOTALS MAY BE 2.5 TO 3.5 INCHES...WITH THE
HEAVIER AMOUNTS ON THE EAST SLOPES OF THE BLUE RIDGE. EVENT MAY
EVENTUALLY TRANSITION INTO AN AREAL FLOOD THREAT AND POSSIBLY RIVER
FLOODING...OF COURSE DEPENDING ON THE AMOUNT OF RAIN...BUT FOR NOW
FLASH FLOODING LOOKS TO BE THE MAIN THREAT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FLASH FLOOD WATCH FROM THIS EVENING THROUGH TUESDAY EVENING
FOR VAZ009-012>017-022-032-033-043.
NC...FLASH FLOOD WATCH FROM THIS EVENING THROUGH TUESDAY EVENING
FOR NCZ001>004-018>020.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...WP
AVIATION...AMS/JH
HYDROLOGY...AMS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
917 AM MDT SUN MAY 13 2012
.UPDATE...UPDATED FORECAST TO EXPIRE THE DENSE FOG ADVISORY THIS
MORNING SINCE THE FOG HAS LIFTED ACROSS MOST OF THE AREA. THE
REMAINDER OF THE FORECAST TODAY AND TONIGHT LOOKS ON TRACK WITH
ISOLATED TO WIDELY SCATTERED SHOWERS AND TSTORMS POSSIBLE SOUTH OF
I80 THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 619 AM MDT SUN MAY 13 2012/
UPDATE...
AVIATION...12Z TAFS
IFR TO LIFR CONDITIONS FROM KLAR EAST TO KSNY...AND ON UP TO KAIA
WILL CONTINUE THRU 13 OR 14Z UNTIL MIXING DISSIPATES THE FOG.
VSBYS SHOULD QUICKLY IMPROVE TO VFR THEREAFTER...AND WILL REMAIN
SO FOR THE REMAINDER OF THE TAF PERIOD ACROSS THE FORECAST AREA.
ISOLATED SHOWERS AND TSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING IN THE SOUTHERN MOUNTAINS AND VICINITY AS NORTHEAST SFC
FLOW COMBINES WITH LINGERING MIDLEVEL ENERGY FROM A SHORTWAVE
TROUGH OVERHEAD. KEPT VCTS AT KLAR AND KCYS THIS AFTERNOON AS THE
CHANCE FOR TSRA MOVING OVER THE AIRFIELD WILL BE LOW HERE. WINDS
WILL REMAIN LIGHT OVERALL AND WILL BECOME SOUTHERLY TONIGHT. ONCE
THE FOG LIFTS THIS MORNING...SKIES SHOULD REMAIN VFR THROUGH THE
REMAINDER OF THE PERIOD.
PREV DISCUSSION... /ISSUED 408 AM MDT SUN MAY 13 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
EARLY MORNING DENSE FOG WILL BE THE INITIAL FORECAST CONCERN
TODAY. SATELLITE FOG PRODUCT DEPICTS THE AREA OF DENSE FOG WAS
EXPANDING ACROSS CENTRAL AND WESTERN LARAMIE COUNTY EARLY THIS
MORNING. MEANWHILE...VISIBILITIES HAVE DECREASED TO 1/4SM AT BOTH
KLAR AND KCYS. 00Z NAM/GFS OUTPUT WAS WEAK ON BOUNDARY LAYER
MOISTURE/SATURATION THIS MORNING. SO HAVE FAVORED 07Z RUC DATA
WHICH HANDLED THE BOUNDARY LAYER MOISTURE MUCH BETTER. IN ADDITION
TO INSULATION...MIXING WILL INCREASE WITH THE APPROACH AND PASSAGE
OF A POSITIVELY TILTED SHORTWAVE THIS MORNING. THUS EXPECT FOG TO
DISSIPATE BY AROUND 15Z. HAVE OPTED TO HOIST A DENSE FOG ADVISORY
FOR AREAS FROM LARAMIE THROUGH CHEYENNE IN EFFECT THROUGH 15Z THIS
MORNING.
00Z MODEL OUTPUT WAS FASTER IN MOVING THE AFOREMENTIONED
SHORTWAVE SOUTH OF THE CWA COMPARED TO YESTERDAY. THIS WILL MOVE
A DRIER AIR MASS INTO THE CWA EARLIER A BIT EARLIER
TODAY...LIMITING CONVECTION POSSIBILITIES ACROSS SE WYOMING.
PROGD SOUNDINGS FOR AREAS NR THE STATELINE STILL INDICATE WEAK
INSTABILITY THIS AFTERNOON...SO CANT RULE OUT A FEW SHOWERS
AND/OR WEAK THUNDERSTORMS. HOWEVER WOULD EXPECT MOST OF THE
ACTIVITY TO REMAIN SOUTH IN COLORADO. TEMPERATURES WILL BE 5 TO
10 DEGREES WARMER TODAY...WITH HIGHS THAT WILL REACH INTO THE 60S
AND LOW 70S.
LARGE SCALE SUBSIDENCE BENEATH A BUILDING MID/UPPER-LEVEL RIDGE
WILL KEEP CONDITIONS DRY FOR MONDAY AND TUESDAY. H7 TEMPERATURES
WILL CLIMB TO 8-10C BOTH DAYS...WHICH WILL YIELD HIGH TEMPERATURES
THAT WILL CLIMB WELL INTO THE 70S...WITH 80S ON THE EASTERN
PLAINS.
LONG TERM...WEDNESDAY THROUGH SUNDAY...BROAD UPPER LEVEL RIDGE
WILL BE OVER MUCH OF THE US ON WEDNESDAY WITH A WEAK SHORTWAVE
MOVING THROUGH THE RIDGE AND ACROSS THE CENTRAL ROCKIES. GFS AND
ECMWF DO NOT BRING MUCH DEEP LAYER MOISTURE ALONG WITH THIS
FEATURE...SO KEPT LOW CHANCES FOR SHOWERS AND THUNDERSTORMS FIRST
IN OROGRAPHIC FAVORED AREAS IN THE AFTERNOON THEN SHIFTING EAST
THROUGH THE EVENING AS A PACIFIC FRONT MOVES ON THROUGH. BREEZY
WEST WINDS WILL OCCUR BEHIND THE FRONT AS WELL. THIS FEATURE AND
ASSOCIATED MOISTURE WILL MOVE TO THE EAST ON THURSDAY WITH THE
RIDGE STILL IN CONTROL OVER THE CENTRAL US. SO EXPECTING VERY WARM
AND DRY CONDITIONS FOR THURSDAY WITH GENERALLY LIGHT SOUTHERLY
WINDS. A SHORTWAVE TROUGH WILL APPROACH FROM THE WEST ON FRIDAY
BUT MODELS ARE HAVING DIFFICULTY HANDLING THIS SYSTEM. ECMWF TENDS
TO PRODUCE A WEAK CUTOFF LOW OVER CALIFORNIA AND NEVADA WHILE GFS
KEEPS A FAST MOVING OPEN WAVE THROUGH THE WEEKS END. INITIAL DRY
SLOTTING AHEAD OF THE WAVE WILL KEEP THE AREA MOSTLY DRY FOR
FRIDAY...WITH INCREASED CHANCES FOR RAIN AND AFTERNOON THUNDER
THROUGH THE WEEKEND AS THIS WAVE MOVES ACROSS THE ROCKIES AND
BRINGS ANOTHER PACIFIC FRONT ALONG WITH IT. AGAIN...UNSURE OF
EXACT TIMING SO KEPT POPS FAIRLY LOW FOR THE WEEKEND. MAX TEMPS
WILL PEAK IN THE UPPER 70S OUT WEST TO UPPER 80S AND LOW 90S
ACROSS THE EASTERN PLAINS FOR THURSDAY AND FRIDAY...WITH A 10 TO
15 DEGREE DROP IN TEMPS EXPECTED FOR THE WEEKEND BEHIND THE
PACIFIC FRONT. ONCE AGAIN...PACIFIC MOISTURE LOOKS QUITE THIN WITH
THIS SYSTEM WITH THE DEEPER PLUME SHUNTED OFF TO THE NORTH. BUT
WILL KEEP THE LOW CHANCES FOR RAIN AND AFTERNOON THUNDER THROUGH
THE WEEKEND...ESPECIALLY AS SFC FLOW SWITCHES TO THE EAST BEHIND
THE FRONT AND ADDS THE UPSLOPE COMPONENT TO HELP TRIGGER
CONVECTION.
FIRE WEATHER... FOG WILL DISSIPATE ACROSS SOUTHEAST WYOMING BY
MID-MORNING. A FEW ISOLATED SHOWERS AND WEAK THUNDERSTORMS WILL BE
POSSIBLE TODAY FOR AREAS OF THE DISTRICT NEAR THE COLORADO
STATELINE. A DRIER AND WARMER AIR MASS WILL MOVE IN FOR EARLY NEXT
WEEK...WITH HIGHS RETURNING BACK INTO THE 70S WEST AND 80S EAST.
MINIMUM RELATIVE HUMIDITIES WILL DROP BACK INTO THE 10 TO 20
PERCENT RANGE ON MONDAY THROUGH THURSDAY. FORTUNATELY WINDS WILL
ONLY PEAK AT AROUND 10 TO 15 MPH EACH AFTERNOON. FRIDAY LOOKS
BREEZIER WITH LOW RELATIVE HUMIDITIES CONTINUING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...TJT
LONG TERM/AVIATION...LIEBL
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
619 AM MDT SUN MAY 13 2012
.UPDATE...
AVIATION...12Z TAFS
IFR TO LIFR CONDITIONS FROM KLAR EAST TO KSNY...AND ON UP TO KAIA
WILL CONTINUE THRU 13 OR 14Z UNTIL MIXING DISSIPATES THE FOG.
VSBYS SHOULD QUICKLY IMPROVE TO VFR THEREAFTER...AND WILL REMAIN
SO FOR THE REMAINDER OF THE TAF PERIOD ACROSS THE FORECAST AREA.
ISOLATED SHOWERS AND TSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING IN THE SOUTHERN MOUNTAINS AND VICINITY AS NORTHEAST SFC
FLOW COMBINES WITH LINGERING MIDLEVEL ENERGY FROM A SHORTWAVE
TROUGH OVERHEAD. KEPT VCTS AT KLAR AND KCYS THIS AFTERNOON AS THE
CHANCE FOR TSRA MOVING OVER THE AIRFIELD WILL BE LOW HERE. WINDS
WILL REMAIN LIGHT OVERALL AND WILL BECOME SOUTHERLY TONIGHT. ONCE
THE FOG LIFTS THIS MORNING...SKIES SHOULD REMAIN VFR THROUGH THE
REMAINDER OF THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 408 AM MDT SUN MAY 13 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
EARLY MORNING DENSE FOG WILL BE THE INITIAL FORECAST CONCERN
TODAY. SATELLITE FOG PRODUCT DEPICTS THE AREA OF DENSE FOG WAS
EXPANDING ACROSS CENTRAL AND WESTERN LARAMIE COUNTY EARLY THIS
MORNING. MEANWHILE...VISIBILITIES HAVE DECREASED TO 1/4SM AT BOTH
KLAR AND KCYS. 00Z NAM/GFS OUTPUT WAS WEAK ON BOUNDARY LAYER
MOISTURE/SATURATION THIS MORNING. SO HAVE FAVORED 07Z RUC DATA
WHICH HANDLED THE BOUNDARY LAYER MOISTURE MUCH BETTER. IN ADDITION
TO INSOLATION...MIXING WILL INCREASE WITH THE APPROACH AND PASSAGE
OF A POSITIVELY TILTED SHORTWAVE THIS MORNING. THUS EXPECT FOG TO
DISSIPATE BY AROUND 15Z. HAVE OPTED TO HOIST A DENSE FOG ADVISORY
FOR AREAS FROM LARAMIE THROUGH CHEYENNE IN EFFECT THROUGH 15Z THIS
MORNING.
00Z MODEL OUTPUT WAS FASTER IN MOVING THE AFOREMENTIONED
SHORTWAVE SOUTH OF THE CWA COMPARED TO YESTERDAY. THIS WILL MOVE
A DRIER AIR MASS INTO THE CWA EARLIER A BIT EARLIER
TODAY...LIMITING CONVECTION POSSIBILITIES ACROSS SE WYOMING.
PROGD SOUNDINGS FOR AREAS NR THE STATELINE STILL INDICATE WEAK
INSTABILITY THIS AFTERNOON...SO CANT RULE OUT A FEW SHOWERS
AND/OR WEAK THUNDERSTORMS. HOWEVER WOULD EXPECT MOST OF THE
ACTIVITY TO REMAIN SOUTH IN COLORADO. TEMPERATURES WILL BE 5 TO
10 DEGREES WARMER TODAY...WITH HIGHS THAT WILL REACH INTO THE 60S
AND LOW 70S.
LARGE SCALE SUBSIDENCE BENEATH A BUILDING MID/UPPER-LEVEL RIDGE
WILL KEEP CONDITIONS DRY FOR MONDAY AND TUESDAY. H7 TEMPERATURES
WILL CLIMB TO 8-10C BOTH DAYS...WHICH WILL YIELD HIGH TEMPERATURES
THAT WILL CLIMB WELL INTO THE 70S...WITH 80S ON THE EASTERN
PLAINS.
LONG TERM...WEDNESDAY THROUGH SUNDAY...BROAD UPPER LEVEL RIDGE
WILL BE OVER MUCH OF THE US ON WEDNESDAY WITH A WEAK SHORTWAVE
MOVING THROUGH THE RIDGE AND ACROSS THE CENTRAL ROCKIES. GFS AND
ECMWF DO NOT BRING MUCH DEEP LAYER MOISTURE ALONG WITH THIS
FEATURE...SO KEPT LOW CHANCES FOR SHOWERS AND THUNDERSTORMS FIRST
IN OROGRAPHIC FAVORED AREAS IN THE AFTERNOON THEN SHIFTING EAST
THROUGH THE EVENING AS A PACIFIC FRONT MOVES ON THROUGH. BREEZY
WEST WINDS WILL OCCUR BEHIND THE FRONT AS WELL. THIS FEATURE AND
ASSOCIATED MOISTURE WILL MOVE TO THE EAST ON THURSDAY WITH THE
RIDGE STILL IN CONTROL OVER THE CENTRAL US. SO EXPECTING VERY WARM
AND DRY CONDITIONS FOR THURSDAY WITH GENERALLY LIGHT SOUTHERLY
WINDS. A SHORTWAVE TROUGH WILL APPROACH FROM THE WEST ON FRIDAY
BUT MODELS ARE HAVING DIFFICULTY HANDLING THIS SYSTEM. ECMWF TENDS
TO PRODUCE A WEAK CUTOFF LOW OVER CALIFORNIA AND NEVADA WHILE GFS
KEEPS A FAST MOVING OPEN WAVE THROUGH THE WEEKS END. INITIAL DRY
SLOTTING AHEAD OF THE WAVE WILL KEEP THE AREA MOSTLY DRY FOR
FRIDAY...WITH INCREASED CHANCES FOR RAIN AND AFTERNOON THUNDER
THROUGH THE WEEKEND AS THIS WAVE MOVES ACROSS THE ROCKIES AND
BRINGS ANOTHER PACIFIC FRONT ALONG WITH IT. AGAIN...UNSURE OF
EXACT TIMING SO KEPT POPS FAIRLY LOW FOR THE WEEKEND. MAX TEMPS
WILL PEAK IN THE UPPER 70S OUT WEST TO UPPER 80S AND LOW 90S
ACROSS THE EASTERN PLAINS FOR THURSDAY AND FRIDAY...WITH A 10 TO
15 DEGREE DROP IN TEMPS EXPECTED FOR THE WEEKEND BEHIND THE
PACIFIC FRONT. ONCE AGAIN...PACIFIC MOISTURE LOOKS QUITE THIN WITH
THIS SYSTEM WITH THE DEEPER PLUME SHUNTED OFF TO THE NORTH. BUT
WILL KEEP THE LOW CHANCES FOR RAIN AND AFTERNOON THUNDER THROUGH
THE WEEKEND...ESPECIALLY AS SFC FLOW SWITCHES TO THE EAST BEHIND
THE FRONT AND ADDS THE UPSLOPE COMPONENT TO HELP TRIGGER
CONVECTION.
FIRE WEATHER... FOG WILL DISSIPATE ACROSS SOUTHEAST WYOMING BY
MID-MORNING. A FEW ISOLATED SHOWERS AND WEAK THUNDERSTORMS WILL BE
POSSIBLE TODAY FOR AREAS OF THE DISTRICT NEAR THE COLORADO
STATELINE. A DRIER AND WARMER AIR MASS WILL MOVE IN FOR EARLY NEXT
WEEK...WITH HIGHS RETURNING BACK INTO THE 70S WEST AND 80S EAST.
MINIMUM RELATIVE HUMIDITIES WILL DROP BACK INTO THE 10 TO 20
PERCENT RANGE ON MONDAY THROUGH THURSDAY. FORTUNATELY WINDS WILL
ONLY PEAK AT AROUND 10 TO 15 MPH EACH AFTERNOON. FRIDAY LOOKS
BREEZIER WITH LOW RELATIVE HUMIDITIES CONTINUING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 9 AM SUNDAY FOR WYZ115-WYZ116-WYZ117-
WYZ118.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...HAHN
LONG TERM/AVIATION...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
408 AM MDT SUN MAY 13 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
EARLY MORNING DENSE FOG WILL BE THE INITIAL FORECAST CONCERN
TODAY. SATELLITE FOG PRODUCT DEPICTS THE AREA OF DENSE FOG WAS
EXPANDING ACROSS CENTRAL AND WESTERN LARAMIE COUNTY EARLY THIS
MORNING. MEANWHILE...VISIBILITIES HAVE DECREASED TO 1/4SM AT BOTH
KLAR AND KCYS. 00Z NAM/GFS OUTPUT WAS WEAK ON BOUNDARY LAYER
MOISTURE/SATURATION THIS MORNING. SO HAVE FAVORED 07Z RUC DATA
WHICH HANDLED THE BOUNDARY LAYER MOISTURE MUCH BETTER. IN ADDITION
TO INSOLATION...MIXING WILL INCREASE WITH THE APPROACH AND PASSAGE
OF A POSITIVELY TILTED SHORTWAVE THIS MORNING. THUS EXPECT FOG TO
DISSIPATE BY AROUND 15Z. HAVE OPTED TO HOIST A DENSE FOG ADVISORY
FOR AREAS FROM LARAMIE THROUGH CHEYENNE IN EFFECT THROUGH 15Z THIS
MORNING.
00Z MODEL OUTPUT WAS FASTER IN MOVING THE AFOREMENTIONED
SHORTWAVE SOUTH OF THE CWA COMPARED TO YESTERDAY. THIS WILL MOVE
A DRIER AIR MASS INTO THE CWA EARLIER A BIT EARLIER
TODAY...LIMITING CONVECTION POSSIBILITIES ACROSS SE WYOMING.
PROGD SOUNDINGS FOR AREAS NR THE STATELINE STILL INDICATE WEAK
INSTABILITY THIS AFTERNOON...SO CANT RULE OUT A FEW SHOWERS
AND/OR WEAK THUNDERSTORMS. HOWEVER WOULD EXPECT MOST OF THE
ACTIVITY TO REMAIN SOUTH IN COLORADO. TEMPERATURES WILL BE 5 TO
10 DEGREES WARMER TODAY...WITH HIGHS THAT WILL REACH INTO THE 60S
AND LOW 70S.
LARGE SCALE SUBSIDENCE BENEATH A BUILDING MID/UPPER-LEVEL RIDGE
WILL KEEP CONDITIONS DRY FOR MONDAY AND TUESDAY. H7 TEMPERATURES
WILL CLIMB TO 8-10C BOTH DAYS...WHICH WILL YIELD HIGH TEMPERATURES
THAT WILL CLIMB WELL INTO THE 70S...WITH 80S ON THE EASTERN
PLAINS.
.LONG TERM...WEDNESDAY THROUGH SUNDAY...BROAD UPPER LEVEL RIDGE
WILL BE OVER MUCH OF THE US ON WEDNESDAY WITH A WEAK SHORTWAVE
MOVING THROUGH THE RIDGE AND ACROSS THE CENTRAL ROCKIES. GFS AND
ECMWF DO NOT BRING MUCH DEEP LAYER MOISTURE ALONG WITH THIS
FEATURE...SO KEPT LOW CHANCES FOR SHOWERS AND THUNDERSTORMS FIRST
IN OROGRAPHIC FAVORED AREAS IN THE AFTERNOON THEN SHIFTING EAST
THROUGH THE EVENING AS A PACIFIC FRONT MOVES ON THROUGH. BREEZY
WEST WINDS WILL OCCUR BEHIND THE FRONT AS WELL. THIS FEATURE AND
ASSOCIATED MOISTURE WILL MOVE TO THE EAST ON THURSDAY WITH THE
RIDGE STILL IN CONTROL OVER THE CENTRAL US. SO EXPECTING VERY WARM
AND DRY CONDITIONS FOR THURSDAY WITH GENERALLY LIGHT SOUTHERLY
WINDS. A SHORTWAVE TROUGH WILL APPROACH FROM THE WEST ON FRIDAY
BUT MODELS ARE HAVING DIFFICULTY HANDLING THIS SYSTEM. ECMWF TENDS
TO PRODUCE A WEAK CUTOFF LOW OVER CALIFORNIA AND NEVADA WHILE GFS
KEEPS A FAST MOVING OPEN WAVE THROUGH THE WEEKS END. INITIAL DRY
SLOTTING AHEAD OF THE WAVE WILL KEEP THE AREA MOSTLY DRY FOR
FRIDAY...WITH INCREASED CHANCES FOR RAIN AND AFTERNOON THUNDER
THROUGH THE WEEKEND AS THIS WAVE MOVES ACROSS THE ROCKIES AND
BRINGS ANOTHER PACIFIC FRONT ALONG WITH IT. AGAIN...UNSURE OF
EXACT TIMING SO KEPT POPS FAIRLY LOW FOR THE WEEKEND. MAX TEMPS
WILL PEAK IN THE UPPER 70S OUT WEST TO UPPER 80S AND LOW 90S
ACROSS THE EASTERN PLAINS FOR THURSDAY AND FRIDAY...WITH A 10 TO
15 DEGREE DROP IN TEMPS EXPECTED FOR THE WEEKEND BEHIND THE
PACIFIC FRONT. ONCE AGAIN...PACIFIC MOISTURE LOOKS QUITE THIN WITH
THIS SYSTEM WITH THE DEEPER PLUME SHUNTED OFF TO THE NORTH. BUT
WILL KEEP THE LOW CHANCES FOR RAIN AND AFTERNOON THUNDER THROUGH
THE WEEKEND...ESPECIALLY AS SFC FLOW SWITCHES TO THE EAST BEHIND
THE FRONT AND ADDS THE UPSLOPE COMPONENT TO HELP TRIGGER
CONVECTION.
&&
.AVIATION...06Z TAFS
CHANCES FOR LOW CONDITIONS BECOMING LESS LIKELY FOR SEVERAL
REASONS. WE ARE SEEING DOWNSLOPING WEST WINDS OFF THE LARAMIE
RANGE HERE AT CHEYENNE...WHICH SHOULD KEEP GOOD FLYING CONDITIONS.
NOT SEEING OVERNIGHT LOWS GETTING TO CROSSOVER TEMPERATURES
EITHER. FINALLY...STILL HAVE THE UPPER SHORTWAVE GETTING READY TO
TRACK INTO SOUTHEAST WYOMING THAT SHOULD HELP TO KEEP FOG FROM
FORMING. YET...VISIBILITIES ARE FALLING. SO AM HESITANT TO
ELIMINATE FOG FROM THE CHEYENNE AND LARAMIE TAFS ALTOGETHER. WILL
KEEP FOG IN THE TAFS WITH GREATEST CHANCE NEAR SUNRISE. FOG...IF
IT DOES HAPPEN WILL BURN OFF QUICKLY THEREAFTER.
CLAYCOMB
&&
.FIRE WEATHER...
FOG WILL DISSIPATE ACROSS SOUTHEAST WYOMING BY MID-MORNING. A FEW
ISOLATED SHOWERS AND WEAK THUNDERSTORMS WILL BE POSSIBLE TODAY FOR
AREAS OF THE DISTRICT NEAR THE COLORADO STATELINE. A DRIER AND
WARMER AIR MASS WILL MOVE IN FOR EARLY NEXT WEEK...WITH HIGHS
RETURNING BACK INTO THE 70S WEST AND 80S EAST. MINIMUM RELATIVE
HUMIDITIES WILL DROP BACK INTO THE 10 TO 20 PERCENT RANGE ON MONDAY
THROUGH THURSDAY. FORTUNATELY WINDS WILL ONLY PEAK AT AROUND 10 TO
15 MPH EACH AFTERNOON. FRIDAY LOOKS BREEZIER WITH LOW RELATIVE
HUMIDITIES CONTINUING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 9 AM SUNDAY FOR WYZ115-WYZ116-WYZ117-
WYZ118.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...HAHN
LONG TERM...RJM
AREA FORECAST DISCUSSION
NWS DENVER CO
1022 AM MDT SUN MAY 13 2012
.UPDATE...
&&
.SHORT TERM...UPPER LEVEL LOW ACROSS NORTHWEST COLORADO THIS
MORNING AND STILL MOVING SOUTH ANDE SOUTHEAST. RUC ANALYSIS
SHOWING BEST QG ASCENT MOVING INTO SOUTHWEST COLORADO WITH
STRONGER SUBSIDENCE MOVING INTO FAR NORTHWEST COLORADO. AREA
SOUNDINGS SHOW COOLING ALOFT IN THE 400-500MB LAYER AND WITH MORE
HEATING THERE WILL BE MORE INSTABILITY TODAY. SURFACE BASED CAPES
GENERALLY 400-800J/KG SO MAYBE SOME SMALL HAIL AND HEAVY WITH WITH
THE STRONGER STORMS...ESPECIALLY IN THE MOUNTAINS AND PALMER
DIVIDE. RADAR IS ALREADY SHOWING SOME LIGHT CONVECTIVE SHOWERS
DEVELOPING OVER THE MOUNTAINS. AGAIN TODAY BEST CHANCE OF SHOWERS
WILL BE MOUNTAINS AND EXTENDING SOUTH INTO PARK COUNTY AND WESTERN
PORTIONS OF THE PALMER DIVIDE. LATER IN THE DAY AS THE STEERING
FLOW TURNS MORE NORTHERLY SHOWERS WILL HAVE A HARDER TIME MOVING
OFF THE MOUNTAINS.
.AVIATION...LOW CLOUDS AND FOG CONTINUE TO DISSIPATE MID MORNING
WHILE CEILINGS CONTINUE TO RISE. APA IS STILL STRUGGLING AS
CONVECTIVE CLOUDS ABOVE THE STRATUS DECK IS ALLOWING LESS HEATING
TO FIGHT THE DISSIPATION. WILL KEEP THE THREAT OF SHOWERS AT LOCAL
TERMINALS AND SOME THUNDER AT BJC/APA WITH A BIT HIGHER THREAT
THERE. DRIER AND MORE STABLE ON MONDAY WITH NO THREAT OF STORMS.
&&
.PREV DISCUSSION... /ISSUED 358 AM MDT SUN MAY 13 2012/
SHORT TERM...EAST/WEST ORIENTED TROUGH DROPPING SOUTH INTO UTAH
AND WESTERN COLORADO. LIFT ASSOCIATED WITH THIS IS ON THE SOUTH
SIDE OF THE TROUGH AND SUBSIDENCE WILL BE WORKING INTO THE STATE
FROM THE NORTH ALONG WITH THE MID AND UPPER LEVEL DRYING. FOR THIS
MORNING...STRATUS AND FOG GRADUALLY REDEVELOPING AND EXPECT A
SHALLOW STRATUS LAYER FOR THE MOST PART...THOUGH WEAK UPSLOPE
WINDS ARE PRODUCING FOG IN THE SLIGHTLY HIGHER TERRAIN AROUND
AKRON AND ALSO ON THE CHEYENNE RIDGE. AS FAR AS CONVECTION GOES WE
WILL HAVE A SLIGHTLY WARMER/DRIER AIR AT LOW LEVELS...BUT STILL
COOL ALOFT SO ACTUALLY A LITTLE MORE CAPE THAN YESTERDAY. HOWEVER
EXPECTING ACTIVITY TO BE MORE LIMITED OVER THE NORTHERN HALF OF
THE AREA DUE TO THE DRYING. CAPES OF 500-1000 J/KG IN A LIGHT
WIND/LOW SHEAR ENVIRONMENT...SO MAYBE SOME BRIEF HEAVY RAIN/SMALL
HAIL WITH THE STRONGEST STORMS. WITH LIGHT EAST WINDS AT THE
SURFACE AND WINDS ALOFT GOING NORTHERLY...COULD SEE SOME
ORGANIZATION ALONG THE FOOTHILLS AND WILL KEEP HIGHER POPS IN THE
SOUTHERN FOOTHILLS AND SOUTH PARK FOR THIS IDEA...BUT AGAIN
STRENGTH OF THE CONVECTION SHOULD NOT BE STRONG ENOUGH FOR MUCH
CONCERN OTHER THEN HIGHER POPS.
CLEARING FROM THE NORTH OVERNIGHT...STILL SOME SURFACE MOISTURE
THAT WILL HELP KEEP TEMPS UP A BIT. MORE MARGINAL FOR
FOG...PROBABLY DEW AND POSSIBLY A LITTLE FROST IN THE COLDEST
SPOTS ON THE PLAINS. AT THIS POINT THAT THREAT LOOKS PRETTY
LIMITED.
LONG TERM...LITTLE IN THE WAY OF ACTIVE WEATHER TO CONTEND WITH
IN THE LONG TERM. AN UPPER LEVEL RIDGE TO THE WEST OF COLORADO
WILL ALLOW FOR A DRY AND WEAK NORTHERLY FLOW OVER THE CWFA FOR
MONDAY THROUGH TUESDAY. INTERACTIVE SOUNDINGS SHOW VERY LITTLE
MOISTURE TO WORK WITH TO KICK OFF THE UPCOMING WEEK. A WEAK UPPER
LEVEL TROUGH LOCATED OVER NORTHERN CA ON MONDAY IS PROGGED TO MAKE
ITS WAY SLOWLY EASTWARD AND BRUSH ACROSS COLORADO ON WEDNESDAY AS
THE UPPER RIDGE FLATTENS. BEST POTENTIAL FOR SHOWERS AND/OR TSTMS
FOR THE CWFA APPEARS TO BE WEDNESDAY INTO WEDNESDAY EVENING. THIS
ALREADY REFLECTED IN THE GRIDS. OTHERWISE...IT WILL BE WARM AND
DRY WITH TEMPERATURES CLIMBING BACK ABOVE NORMAL TUESDAY THROUGH
SATURDAY.
AVIATION...EXPECT A SHALLOW LAYER OF LOW CLOUDS TO BECOME MORE
WIDESPREAD BY SUNRISE WITH MVFR/IFR CEILINGS AND VISIBILITIES.
COULD BE A FEW PATCHES OF SHALLOW GROUND FOG WITH LIFR CONDITIONS
BUT EXPECT THE COVERAGE TO BE VERY LIMITED. LOW CLOUDS SHOULD BURN
OFF FAIRLY QUICKLY...WITH VFR CONDITIONS BY 16Z. SCATTERED SHOWERS
AND THUNDERSTORMS WILL DEVELOP IN THE MID TO LATE AFTERNOON AND
CONTINUE INTO EARLY EVENING...MAINLY FROM DENVER WESTWARD AND
SOUTHWARD. DURING THIS TIME INSTRUMENT APPROACHES MAY BE NEEDED TO KDEN.
HYDROLOGY...EXPECTING LESS COVERAGE OF THUNDERSTORMS TODAY BUT
SOME OF THEM COULD BE STRONGER. WINDS ARE LIGHT AND COULD FAVOR
ORGANIZATION OF SLOW MOVING STORMS OVER THE EAST SLOPES OF THE
FRONT RANGE. HOWEVER...MOISTURE IS LIMITED AND STORMS ARE STILL
NOT EXPECTED TO HAVE INTENSE UPDRAFTS OR BE WELL ORGANIZED. BRIEF
HEAVY RAIN IS POSSIBLE...BUT AGAIN IT LOOKS LIKE THE HEAVIEST RAIN
WILL LIKELY BE HALF AN INCH IN AN HOUR OR LESS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
156 PM EDT SUN MAY 13 2012
.PREV DISCUSSION... /ISSUED 1018 AM EDT SUN MAY 13 2012/
UPDATE...
WHILE AREA OF WIDESPREAD RAIN CONTINUES TO PUSH NORTHEASTWARD...
SCATTERED SHOWERS SHOULD CONTINUE THROUGHOUT THE DAY. HAVE
INCREASED POPS SOME TO THE SOUTH AS LOOKS TO BE A GOOD CHANCE FOR
CONTINUED MOISTURE ADVECTION AND SHOWER DEVELOPMENT. RUC FORECAST
CAPE VALUES ARE AROUND 1000 J/KG IN THE WESTERN PORTION OF THE
AREA BY 00Z WITH AND A MODIFIED 12Z FFC SOUNDING GAVE NEAR 600
J/KG BY 21Z... THEREFORE WILL MAINTAIN A SLIGHT CHANCE OF TS THIS
AFTERNOON. ALL ELSE OF FORECAST APPEARED TO BE ON TRACK.
03
PREV DISCUSSION... /ISSUED 434 AM EDT SUN MAY 13 2012/
SHORT TERM /TODAY THROUGH MONDAY/...
MUCH NEEDED RAIN CONTINUES ACROSS MOST OF THE CWA THIS MORNING AND
HEAVY RAIN CONTINUES TO BE THE MAIN THREAT. HIGH CHANCES CONTINUE THROUGH
TONIGHT ACROSS NORTH AND WEST GEORGIA AND THEN BEGIN TO DECREASE
POPS ON MONDAY.
TROUGH AXIS REMAINS OVER THE MISSISSIPPI VALLEY THIS MORNING WHILE
THE SFC LOW WAS EXITING MISSISSIPPI. THIS SYSTEM HAS RESULTED IN
HIGH CHANCE OF POPS ACROSS MOST OF THE CWA. AREA OF RAIN THIS
MORNING WILL CONTINUE TO PUSH NORTHEAST AND BY THIS AFTERNOON BEST
RAIN CHANCES WILL SHIFT TO THE NORTH WHILE THE LEAST FAVORABLE AREA
FOR PRECIP WILL BE ACROSS THE SOUTHEAST. THE CLOSE PROXIMITY OF THE
SFC LOW /WITH THE CWA IN THE WARM SECTOR/ AND THE UPPER LEVEL
FORCING FROM THE TROUGH WILL ALLOW FOR INCREASED THUNDER CHANCES
THIS AFTERNOON. GFS MU CAPE INDICATES BEST CHANCE FOR THUNDER ACROSS
THE WESTERN PORTION OF THE CWA WITH VALUES AROUND 1000 J/KG.
ALTHOUGH DECENT INSTABILITY THIS AFTERNOON WILL ALLOW FOR
THUNDERSTORM DEVELOPMENT...SEVERE STORMS ARE NOT EXPECTED. SPC
CURRENTLY ONLY HAS THE AREA IN SEE TEXT. TONIGHT...WITH UPPER LEVEL
SYSTEM STILL NEARBY AND SFC LOW MOVING OVER NW GA...INSTABILITY IS
LOW BUT ENOUGH TO POSSIBLY PRODUCE THUNDERSTORMS SO INCLUDED A SLIGHT
CHANCE.
ON MONDAY MAIN TROUGH AXIS MOVES INTO THE CWA BUT A SHORTWAVE
DEVELOPS IN THE LONG WAVE TROUGH WEST OF THE AREA. IT WILL BE AWHILE
BEFORE WE CAN PUSH THE LONG WAVE TROUGH OUT OF OUR AREA. THIS WILL
ALLOW OUR SHOWER AND THUNDERSTORM CHANCE TO CONTINUE BUT CHANCES
WILL BEGIN TO DECREASE AS THE SFC LOW CONTINUES MOVING ALONG THE
APPALACHIANS AND SFC FRONT PUSHING INTO GEORGIA.
MAIN CONCERN THROUGH THE SHORT TERM CONTINUES TO BE HEAVY RAIN
THREAT. SEE THE HYDROLOGY SECTION FOR DETAILS.
CLOUD COVERAGE THROUGH THE SHORT TERM WILL HELP TO MODERATE TEMPS
AND KEEP MOST OF THE CWA IN THE 70S TODAY. MAV/MET TEMPS ARE VERY
SIMILAR THROUGH MONDAY. STUCK CLOSE TO A MAV/MET BLEND.
11
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
EXTENDED PROGS CONTINUE TO SHOW A BROAD UPPER TROF OVER THE
SOUTHEAST U.S. INTO THURSDAY BEFORE UPPER RIDGE BEGINS TO BUILD IN
FROM THE WEST THURSDAY NIGHT/FRIDAY. AT THE SURFACE MODELS
MAINTAIN WAVY FRONTAL BOUNDARY SOMEWHERE ACROSS CENTRAL GEORGIA
INTO TUESDAY NIGHT...BEFORE SHIFTING INTO SOUTH GEORGIA WEDNESDAY.
WITH THIS BOUNDARY STILL IN THE VICINITY AND UPPER TROF OVER THE
REGION WILL NEED TO HOLD ON TO SLIGHT CHANCE TO CHANCE POPS FOR
MUCH OF THE COUNTY WARNING AREA INTO TUESDAY...THEN FOCUS SHIFTING
MORE TO EAST SIDE OF THE STATE TUESDAY NIGHT/WEDNESDAY WITH MODELS
SHOWING BEST MOISTURE OVER THE CAROLINAS. WILL KEEP FORECAST DRY
THURSDAY INTO SATURDAY WITH WEAK RIDGE OVER THE AREA. HOWEVER...
WITH BOTH ECMWF AND GFS HINTING AT A COASTAL LOW DEVELOPING ALONG
THE MID ATLANTIC/SOUTHEAST COAST OVER THE WEEKEND WILL NEED TO
KEEP A CLOSE WATCH ON FUTURE RUNS TO SEE HOW MODELS HANDLE THIS
FEATURE. HAVE GONE WITH JUST CLOUDS FOR NOW.
49
HYDROLOGY...
HPC DAY 1-2 QPF STILL INDICATES 1-2 INCHES ACROSS NORTH GEORGIA WITH
2 INCHES ACROSS THE NORTHEAST AND 1 INCH ACROSS CENTRAL GEORGIA.
THIS IS VERY CLOSE TO THE TOTALS ADVERTISED IN THE FORECAST. AT THIS
TIME IT APPEARS THE RIVERS/CREEKS/STREAMS SHOULD BE ABLE TO HANDLE
THIS AMOUNT...ESPECIALLY GIVEN THAT THE AMOUNTS ARE SPREAD OUT OVER
A FEW DAYS. WILL CONTINUE TO MONITOR THOUGH FOR ANY LOCALIZED
PROBLEMS THAT MAY ARISE ON THE NORTHERN CREEKS AND STREAMS.
11
.AVIATION...
18Z UPDATE...
MVFR CIGS THIS AFTERNOON LOWERING TO IFR LEVELS TONIGHT. SCATTERED
SHOWERS ARE EXPECTED THROUGH THE MAJORITY OF THE TAF PERIOD WITH
ALL SITES EXCEPT KAHN POSSIBLY HAVING -TSRA MID AFTERNOON INTO
EARLY EVENING. CIGS SHOULD STAY AROUND 1500 TO 2000 FT AND LOWER
TO NEAR 700 FT FROM APPROXIMATELY 06-15Z. WINDS WILL GRADUALLY
SHIFT FROM SOUTHEASTERLY TO SOUTHWESTERLY BY EARLY MORNING MONDAY.
VISBYS SHOULD REMAIN AT OR ABOVE 4SM OVERNIGHT. THE CHANCE FOR
-TSRA WILL RETURN AGAIN MONDAY AFTERNOON SO INCLUDED PROB30 AT
KATL WHILE REMAINING BEYOND THE FORECAST PERIOD FOR ALL OTHER
SITES.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON CIGS THIS AFTERNOON.
HIGH CONFIDENCE ON ALL ELSE.
03
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 72 61 79 60 / 100 80 50 40
ATLANTA 73 62 77 61 / 100 70 30 20
BLAIRSVILLE 65 59 72 53 / 100 90 60 50
CARTERSVILLE 72 60 77 57 / 100 80 40 20
COLUMBUS 79 64 81 62 / 70 50 30 20
GAINESVILLE 69 61 76 59 / 100 90 40 40
MACON 79 64 80 62 / 90 50 30 20
ROME 76 62 79 58 / 100 80 40 30
PEACHTREE CITY 75 60 77 57 / 90 60 30 20
VIDALIA 82 66 84 65 / 100 40 30 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11/03
LONG TERM....49
AVIATION...03
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
355 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...SHOWERS REMAIN SCATTERED MAINLY OVER SOUTH
CAROLINA THIS AFTERNOON WHERE RICHER DEWPOINT AIR EXISTS WITH
READINGS IN THE MID 60S. DRIER AIR STILL EXISTS FROM CAPE FEAR
NORTH CLOSER TO THE COAST WHERE DEWPOINT TEMPS WERE IN THE MID
50S. HIGHER HRRR CAPE VALUES ALIGNING NICELY WITH SHWR DEVELOPMENT
OVER SC AND INLAND NC ZONES. CLOUD COVER MODERATING TEMPS
OVERALL...ESPECIALLY WHERE PCP OCCURRED THROUGH THE DAY.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
OVER SC MAINLY THROUGH LATE AFTERNOON WHILE COASTAL NC BECOMES
SLIGHTLY DRIER. MAIN AREA OF PCP MOVING UP THROUGH GA AND SC
AHEAD OF LOW TRACKING NORTH THROUGH TENNESSEE THROUGH TONIGHT.
DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND SOUTH CAROLINA
TRACKING INTO NC. PCP WATER VALUES WILL REACH UP AROUND 1.5 INCHES
INLAND WHILE STILL REMAINING QUITE DRY FROM CAPE FEAR NORTHWARD
WHERE PCP WATER VALUES REMAIN LESS THAN AN INCH CLOSER TO THE COAST.
EXPECT MOST OF THE SHWR ACTIVITY TO REMAIN SOUTH AND WEST OF CWA
WITH LESS IN THE WAY OF PCP ACROSS COASTAL NC THROUGH MUCH OF
TONIGHT. MOISTURE PROFILES OVER LOCAL AREA SHOWING MOISTURE
THINNING OUT THROUGH THE COLUMN IN THE MID LAYERS THROUGH THIS
EVENING. CAN NOT RULE OUT SOME SHWRS AS SHORTWAVE ROTATES AROUND
PROVIDING SOME MINOR PERTURBATIONS TO SUPPORT SOME CONVECTIVE
DEVELOPMENT BUT OVERALL EXPECT MORE ISOLATED THROUGH THIS EVENING
WITH BETTER CONVECTIVE DEVELOPMENT POSSIBLE LATER TONIGHT ACROSS
THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL
WATERS.
TEMPS WILL ONLY DROP INTO THE LOWER 60S MOST PLACES OVERNIGHT WITH
PLENTY OF MOISTURE PRESENT AND CONSIDERABLE CLOUD COVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 340 PM SUNDAY...SFC HIGH PRESSURE TO RETREAT FARTHER OFFSHORE
MONDAY. THIS WILL ALLOW A SFC COLD FRONT ALBEIT WEAK...TO TRACK TO
THE WESTERN CAROLINAS FROM THE GULF COAST STATES BY TUESDAY. THIS
WILL OPEN UP BOTH THE GULF OF MEXICO AND ATLANTIC MOISTURE FEEDS
ACROSS THE FA BY MIDDAY MONDAY...AND CONTINUE THROUGH TUESDAY NIGHT.
THE BEST SHOT FOR POPS FROM CONVECTION WILL RUN FROM MONDAY
AFTERNOON THROUGH DAYBREAK TUESDAY. MID-LEVEL IMPULSES ARE PROGGED
TO WEAKEN AS THEY REACH AND TRACK ACROSS THE FA...NEVERTHELESS THIS
WILL CONTINUE TO BE A FOCUS FOR CONVECTION DEVELOPMENT. PROGGED
NAMBUFR SOUNDINGS INDICATE A NEARLY SATURATED ATM COLUMN ACROSS THE
FA WITH 1.5 TO 1.9 PWS MONDAY NIGHT. COULD OBSERVE WIDESPREAD 3/4 TO
1 1/4 INCHES OF RAINFALL ACROSS THE REGION THROUGH TUESDAY DAYBREAK.
THE DRY GROUNDS AND VEGETATION ACROSS THE REGION WILL ACT LIKE
SPONGES. HOWEVER WILL STILL CONTINUE TO INDICATE IN THE HWO ABOUT
THE POSSIBILITY OF FLOODING RAINS ACROSS ISOLATED LOCALES THAT COULD
EXPERIENCE UP TO 2 INCHES OF RAINFALL. FOR TUESDAY...DIURNALLY
DRIVEN CONVECTION WILL TAKE OVER WITH THE AID OF THE NEARLY STALLED
SFC COLD FRONT AS A TRIGGER. UPPER LEVEL IMPULSES NOT AS PRONOUNCED
THAT WILL AFFECT THE FA LATE MONDAY INTO MONDAY NIGHT. MAX/MIN TEMPS
WILL HOVER WITHIN 3 DEGREES ON EITHER SIDE OF THE CLIMO NORMS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 340 PM SUNDAY...EARLY PORTION OF THE FORECAST IS FAIRLY
STRAIGHT FORWARD. BROAD TROUGHING ALOFT...WITH THE AXIS WEST OF THE
AREA...RESULTS IN DEEP SOUTHWEST FLOW PARALLEL TO SURFACE BOUNDARIES
STALLED IN THE AREA. TYPICALLY THIS YIELDS UNSETTLED...THOUGH NOT
VERY WIDESPREAD...WEATHER. WILL BUMP POP A BIT HIGHER WED BUT STILL
IN THE CHC RANGE AT THIS POINT. TIMING ANY POTENTIAL SHORTWAVES THAT
COULD ENHANCE STORMS AND CREATE MORE COVERAGE AT THIS POINT IS
DIFFICULT AT BEST SO FURTHER POPS REFINEMENTS...BOTH SPATIAL AND
TEMPORAL...WILL BE NEEDED. POTENT SHORTWAVE OUT OF THE WEST HELPS
PUSH THE UPPER TROUGH AND THE STALLED FRONT OFFSHORE WED NIGHT INTO
THU. MOISTURE AND THE THREAT OF PRECIP LINGERS INTO THU WITH TROUGH
AXIS/UPPER LOW OVER HEAD AND SLOW TO MOVE EAST. AT THIS POINT THE
ECMWF/HPC SOLUTION DIFFERS FROM THE GFS/CANADIAN SOLUTION.
00Z ECMWF AND HPC SOLUTIONS DIG THE UPPER TROUGH A BIT DEEPER OVER
THE NORTHERN GOMEX WHICH RESULTS IN A SEMI-CUTOFF UPPER LOW OVER
OVER GA/NORTHERN FL. THIS INDUCES A SURFACE LOW WHICH STARTS OUT
COLD CORE BUT COULD BECOME A HYBRID SYSTEM AS IT MOVES NORTH ALONG
THE COAST. THE 12Z GFS/CANADIAN SOLUTIONS AND A NUMBER OF THE GFS
ENSEMBLE MEMBERS SUPPORT LESS AMPLIFICATION OF THE 5H TROUGH OVER
THE NORTHERN GOMEX...WHICH RESULTS IN THE SYSTEM DEVELOPING MUCH
FARTHER OFF THE COAST. GIVEN BOTH SOLUTIONS SHOW A SYSTEM DEVELOPING
HAVE HIGH CONFIDENCE SOMETHING WILL EXIST OFF THE COAST LATE IN THE
PERIOD...BUT DETAILS REMAIN FUZZY. LOW CONFIDENCE AND THE POTENTIAL
FOR FORECAST FLIP-FLOPPING WILL NOT MAKE MUCH IN THE WAY OF CHANGES
BEYOND THU...KEEPING INHERITED SLIGHT CHC POP. TEMPERATURES WILL BE
WITHIN A DEGREE OR TWO OF CLIMO THROUGH THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...A PERSISTENT AREA OF SHOWERS IS MOVING ONSHORE NEAR
GGE/MYR/CRE REACHING AS FAR INLAND AS LBT. FLIGHT CONDITIONS
ASSOCIATED WITH THIS AREA OF SHOWERS HAVE BEEN PREDOMINATELY
MVFR...BUT TEMPO PERIODS OF IFR HAVE OCCURRED. ELSEWHERE...FLO/LBT
HAS EXPERIENCED TEMPO PERIODS OF MVFR CEILINGS...WHILE ILM HAS
REMAINED VFR. SHOWERS WERE DEVELOPING SOUTH OF FLO.
TEMPO PERIODS OF SHOWERS/MVFR CONDITIONS WILL REMAIN POSSIBLE AT ALL
TERMINALS EXCEPT ILM THROUGH MID-LATE AFTERNOON. BY LATE
AFTERNOON/EARLY EVENING SHOWERS SHOULD BE AFFECTING MAINLY THE
FLO/LBT TERMINALS...ALTHOUGH SOME RESIDUAL SHOWERS FROM THE AREA
CURRENTLY NEAR MYR/CRE COULD AFFECT THE ILM TERMINAL BY THEN. EXPECT
ANY ACTIVITY NEAR ILM TO BE VERY LIGHT.
PRECIPITATION WILL BECOME VERY ISOLATED OR WILL END ALL-TOGETHER
DURING THE EVENING AS SIGNIFICANT LIFT DECREASES. THROUGH THE
OVERNIGHT HOURS PERIODS OF MVFR CAN BE EXPECTED. BY SUNRISE SHOWERS
WILL AGAIN INCREASE FROM THE SOUTHWEST WITH GOOD CHANCES OF
SHOWER/MVFR CONDITIONS DURING THE MORNING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT THIS
MORNING BUT UP TO 4 FT JUST SOUTH AND EAST OF LOCAL WATERS. SOUTHEAST
WINDS UP AROUND 15 KTS WILL CONTINUE AS GRADIENT TIGHTENS BETWEEN
DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH PRESSURE WELL OFF
THE NORTH CAROLINA COAST. WINDS WILL VEER SLIGHTLY THROUGH TONIGHT
BECOMING MORE NORTHERLY AS LOW TRACKS FARTHER NORTH AND EAST. THIS
PERSISTENT ON SHORE FLOW THROUGH TONIGHT WILL BUILD SEAS UP TO 3
TO 4 FT WITH SOME 5 FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...REMAINING ISOLATED THROUGH MOST OF THE NIGHT WITH
POSSIBLE REDEVELOPMENT LATER TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 350 PM SUNDAY...HIGH PRESSURE TO RETREAT FURTHER OFFSHORE AND
THE HIGH SEAS THROUGH THE PERIOD. SFC COLD FRONT TO SLOWLY PUSH TO
THE WATERS BY THE END OF THE PERIOD. THIS OPENS UP A SSE TO SSW WIND
DIRECTION MONDAY INTO TUESDAY. THE TIGHTENED SFC PG WILL OCCUR
MONDAY INTO EARLY TUESDAY...BEFORE RELAXING AS THE FRONTAL BOUNDARY
TURTLES ITS WAY EASTWARD BEFORE STALLING JUST INLAND FROM THE COAST
BY EARLY WEDNESDAY. WINDS WILL BE AT THEIR PEAK LATE MONDAY INTO
MONDAY NIGHT...WITH SPEEDS 15 TO 20 KT. AN ESE GROUND SWELL AT 7-8
SECOND PERIODS WILL COMBINE WITH LOCALLY PRODUCED 3 TO 5 SECOND
PERIOD WIND WAVES...TO PRODUCE 3 TO 5 FT SEAS. A FEW 6 FOOTERS
REMAIN POSSIBLE ESPECIALLY THE OUTER WATERS OFF CAPE FEAR AND CAPE
ROMAIN. THE TIME FRAME FOR THIS OCCURRENCE...MONDAY AFTERNOON INTO
TUESDAY NIGHT. NOT ALL THAT CONVINCED THAT SCA CRITERIA WILL BE MET
FOR ANY LENGTH OF TIME. HOWEVER SCEC THRESHOLDS WILL BE MET AND
LIKELY RAISED TONIGHT OR MONDAY UNLESS FUTURE MODEL RUNS INDICATE
INCREASED OCCURRENCE FOR SCA CRITERIA.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 340 PM SUNDAY...SOUTHWEST FLOW OVER THE WATERS WED WITH FRONT
STALLED VERY CLOSE TO THE COAST. PROXIMITY TO THE BOUNDARY WILL KEEP
SOUTHWEST FLOW 10 KT OR LESS ALL DAY. FRONT IS PUSHED OFF THE COAST
LATE WED NIGHT INTO THU WITH WINDS VEERING FROM NORTHWEST
IMMEDIATELY BEHIND THE FRONT TO NORTHEAST BY MID TO LATE MORNING
THU. OFFSHORE FLOW STARTS OUT AROUND 10 KT BUT COLD SURGE LATE THU
NIGHT WILL PUSH SPEEDS CLOSE TO 15 KT AWAY FROM SHORE. FRI COULD BE
QUITE INTERESTING IF THE 00Z ECMWF/HPC SOLUTION VERIFIES. THESE
SOLUTIONS BRING LOW PRESSURE...POTENTIALLY A TROPICAL HYBRID...INTO
THE COASTAL WATERS LATE FRI AND KEEPS IT IN THE AREA SAT. AT THIS
POINT THE EVENT LOOKS LIKE IT WOULD BE A SOLID SCA EVENT...AGAIN IN
THE 00Z ECMWF/HPC SOLUTION VERIFIES. THE 12Z GFS/CANADIAN HAS THE
LOW MUCH FARTHER OFF THE COAST WITH CONTINUED SOLID 15 KT NORTHEAST
FLOW SAT AND SUN. FOR NOW HAVE CONTINUED NORTHEAST FLOW THROUGH THE
END OF THE PERIOD WITH FURTHER ADJUSTMENTS EXPECTED AS THE CORRECT
SOLUTION BECOMES MORE DEFINED.
SEAS 2 TO 4 FT WITH SOME SWAN SUGGESTING A BIT OF SOUTHERLY SWELL
STARTING TO DEVELOP WED. PASSAGE OF COLD FRONT AND RESULTING
NORTHERLY FLOW WILL CREATE CHAOTIC 2 TO 4 FT SEAS WED NIGHT AND THU.
COLD SURGE THU NIGHT WILL INCREASE SEAS FRI...3 TO 4 FT EXCEPT FOR
AREAS BLOCKED TO NORTHEAST FLOW WHERE SEAS WILL BE 1 TO 2 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...III
AVIATION...RGZ/MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
330 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...SHOWERS REMAIN SCATTERED MAINLY OVER SOUTH
CAROLINA THIS AFTERNOON WHERE RICHER DEWPOINT AIR EXISTS WITH
READINGS IN THE MID 60S. DRIER AIR STILL EXISTS FROM CAPE FEAR
NORTH CLOSER TO THE COAST WHERE DEWPOINT TEMPS WERE IN THE MID
50S. HIGHER HRRR CAPE VALUES ALIGNING NICELY WITH SHWR DEVELOPMENT
OVER SC AND INLAND NC ZONES. CLOUD COVER MODERATING TEMPS
OVERALL...ESPECIALLY WHERE PCP OCCURRED THROUGH THE DAY.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
OVER SC MAINLY THROUGH LATE AFTERNOON WHILE COASTAL NC BECOMES
SLIGHTLY DRIER. MAIN AREA OF PCP MOVING UP THROUGH GA AND SC
AHEAD OF LOW TRACKING NORTH THROUGH TENNESSEE THROUGH TONIGHT.
DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND SOUTH CAROLINA
TRACKING INTO NC. PCP WATER VALUES WILL REACH UP AROUND 1.5 INCHES
INLAND WHILE STILL REMAINING QUITE DRY FROM CAPE FEAR NORTHWARD
WHERE PCP WATER VALUES REMAIN LESS THAN AN INCH CLOSER TO THE COAST.
EXPECT MOST OF THE SHWR ACTIVITY TO REMAIN SOUTH AND WEST OF CWA
WITH LESS IN THE WAY OF PCP ACROSS COASTAL NC THROUGH MUCH OF
TONIGHT. MOISTURE PROFILES OVER LOCAL AREA SHOWING MOISTURE
THINNING OUT THROUGH THE COLUMN IN THE MID LAYERS THROUGH THIS
EVENING. CAN NOT RULE OUT SOME SHWRS AS SHORTWAVE ROTATES AROUND
PROVIDING SOME MINOR PERTURBATIONS TO SUPPORT SOME CONVECTIVE
DEVELOPMENT BUT OVERALL EXPECT MORE ISOLATED THROUGH THIS EVENING
WITH BETTER CONVECTIVE DEVELOPMENT POSSIBLE LATER TONIGHT ACROSS
THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL
WATERS.
TEMPS WILL ONLY DROP INTO THE LOWER 60S MOST PLACES OVERNIGHT WITH
PLENTY OF MOISTURE PRESENT AND CONSIDERABLE CLOUD COVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 340 PM SUNDAY...
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 340 PM SUNDAY...EARLY PORTION OF THE FORECAST IS FAIRLY
STRAIGHT FORWARD. BROAD TROUGHING ALOFT...WITH THE AXIS WEST OF THE
AREA...RESULTS IN DEEP SOUTHWEST FLOW PARALLEL TO SURFACE BOUNDARIES
STALLED IN THE AREA. TYPICALLY THIS YIELDS UNSETTLED...THOUGH NOT
VERY WIDESPREAD...WEATHER. WILL BUMP POP A BIT HIGHER WED BUT STILL
IN THE CHC RANGE AT THIS POINT. TIMING ANY POTENTIAL SHORTWAVES THAT
COULD ENHANCE STORMS AND CREATE MORE COVERAGE AT THIS POINT IS
DIFFICULT AT BEST SO FURTHER POPS REFINEMENTS...BOTH SPATIAL AND
TEMPORAL...WILL BE NEEDED. POTENT SHORTWAVE OUT OF THE WEST HELPS
PUSH THE UPPER TROUGH AND THE STALLED FRONT OFFSHORE WED NIGHT INTO
THU. MOISTURE AND THE THREAT OF PRECIP LINGERS INTO THU WITH TROUGH
AXIS/UPPER LOW OVER HEAD AND SLOW TO MOVE EAST. AT THIS POINT THE
ECMWF/HPC SOLUTION DIFFERS FROM THE GFS/CANADIAN SOLUTION.
00Z ECMWF AND HPC SOLUTIONS DIG THE UPPER TROUGH A BIT DEEPER OVER
THE NORTHERN GOMEX WHICH RESULTS IN A SEMI-CUTOFF UPPER LOW OVER
OVER GA/NORTHERN FL. THIS INDUCES A SURFACE LOW WHICH STARTS OUT
COLD CORE BUT COULD BECOME A HYBRID SYSTEM AS IT MOVES NORTH ALONG
THE COAST. THE 12Z GFS/CANADIAN SOLUTIONS AND A NUMBER OF THE GFS
ENSEMBLE MEMBERS SUPPORT LESS AMPLIFICATION OF THE 5H TROUGH OVER
THE NORTHERN GOMEX...WHICH RESULTS IN THE SYSTEM DEVELOPING MUCH
FARTHER OFF THE COAST. GIVEN BOTH SOLUTIONS SHOW A SYSTEM DEVELOPING
HAVE HIGH CONFIDENCE SOMETHING WILL EXIST OFF THE COAST LATE IN THE
PERIOD...BUT DETAILS REMAIN FUZZY. LOW CONFIDENCE AND THE POTENTIAL
FOR FORECAST FLIP-FLOPPING WILL NOT MAKE MUCH IN THE WAY OF CHANGES
BEYOND THU...KEEPING INHERITED SLIGHT CHC POP. TEMPERATURES WILL BE
WITHIN A DEGREE OR TWO OF CLIMO THROUGH THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...A PERSISTENT AREA OF SHOWERS IS MOVING ONSHORE NEAR
GGE/MYR/CRE REACHING AS FAR INLAND AS LBT. FLIGHT CONDITIONS
ASSOCIATED WITH THIS AREA OF SHOWERS HAVE BEEN PREDOMINATELY
MVFR...BUT TEMPO PERIODS OF IFR HAVE OCCURRED. ELSEWHERE...FLO/LBT
HAS EXPERIENCED TEMPO PERIODS OF MVFR CEILINGS...WHILE ILM HAS
REMAINED VFR. SHOWERS WERE DEVELOPING SOUTH OF FLO.
TEMPO PERIODS OF SHOWERS/MVFR CONDITIONS WILL REMAIN POSSIBLE AT ALL
TERMINALS EXCEPT ILM THROUGH MID-LATE AFTERNOON. BY LATE
AFTERNOON/EARLY EVENING SHOWERS SHOULD BE AFFECTING MAINLY THE
FLO/LBT TERMINALS...ALTHOUGH SOME RESIDUAL SHOWERS FROM THE AREA
CURRENTLY NEAR MYR/CRE COULD AFFECT THE ILM TERMINAL BY THEN. EXPECT
ANY ACTIVITY NEAR ILM TO BE VERY LIGHT.
PRECIPITATION WILL BECOME VERY ISOLATED OR WILL END ALL-TOGETHER
DURING THE EVENING AS SIGNIFICANT LIFT DECREASES. THROUGH THE
OVERNIGHT HOURS PERIODS OF MVFR CAN BE EXPECTED. BY SUNRISE SHOWERS
WILL AGAIN INCREASE FROM THE SOUTHWEST WITH GOOD CHANCES OF
SHOWER/MVFR CONDITIONS DURING THE MORNING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT THIS
MORNING BUT UP TO 4 FT JUST SOUTH AND EAST OF LOCAL WATERS. SOUTHEAST
WINDS UP AROUND 15 KTS WILL CONTINUE AS GRADIENT TIGHTENS BETWEEN
DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH PRESSURE WELL OFF
THE NORTH CAROLINA COAST. WINDS WILL VEER SLIGHTLY THROUGH TONIGHT
BECOMING MORE NORTHERLY AS LOW TRACKS FARTHER NORTH AND EAST. THIS
PERSISTENT ON SHORE FLOW THROUGH TONIGHT WILL BUILD SEAS UP TO 3
TO 4 FT WITH SOME 5 FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...REMAINING ISOLATED THROUGH MOST OF THE NIGHT WITH
POSSIBLE REDEVELOPMENT LATER TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 340 AM SUNDAY...SFC HIGH PRESSURE TO RETREAT FARTHER OFFSHORE
MONDAY. THIS WILL ALLOW A SFC COLD FRONT ALBEIT WEAK...TO TRACK TO
THE WESTERN CAROLINAS FROM THE GULF COAST STATES BY TUESDAY. THIS
WILL OPEN UP BOTH THE GULF OF MEXICO AND ATLANTIC MOISTURE FEEDS
ACROSS THE FA BY MIDDAY MONDAY...AND CONTINUE THROUGH TUESDAY NIGHT.
THE BEST SHOT FOR POPS FROM CONVECTION WILL RUN FROM MONDAY
AFTERNOON THROUGH DAYBREAK TUESDAY. MID-LEVEL IMPULSES ARE PROGGED
TO WEAKEN AS THEY REACH AND TRACK ACROSS THE FA...NEVERTHELESS THIS
WILL CONTINUE TO BE A FOCUS FOR CONVECTION DEVELOPMENT. PROGGED
NAMBUFR SOUNDINGS INDICATE A NEARLY SATURATED ATM COLUMN ACROSS THE
FA WITH 1.5 TO 1.9 PWS MONDAY NIGHT. COULD OBSERVE WIDESPREAD 3/4 TO
1 1/4 INCHES OF RAINFALL ACROSS THE REGION THROUGH TUESDAY DAYBREAK.
THE DRY GROUNDS AND VEGETATION ACROSS THE REGION WILL ACT LIKE
SPONGES. HOWEVER WILL STILL CONTINUE TO INDICATE IN THE HWO ABOUT
THE POSSIBILITY OF FLOODING RAINS ACROSS ISOLATED LOCALES THAT COULD
EXPERIENCE UP TO 2 INCHES OF RAINFALL. FOR TUESDAY...DIURNALLY
DRIVEN CONVECTION WILL TAKE OVER WITH THE AID OF THE NEARLY STALLED
SFC COLD FRONT AS A TRIGGER. UPPER LEVEL IMPULSES NOT AS PRONOUNCED
THAT WILL AFFECT THE FA LATE MONDAY INTO MONDAY NIGHT. MAX/MIN TEMPS
WILL HOVER WITHIN 3 DEGREES ON EITHER SIDE OF THE CLIMO NORMS.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 340 PM SUNDAY...SOUTHWEST FLOW OVER THE WATERS WED WITH FRONT
STALLED VERY CLOSE TO THE COAST. PROXIMITY TO THE BOUNDARY WILL KEEP
SOUTHWEST FLOW 10 KT OR LESS ALL DAY. FRONT IS PUSHED OFF THE COAST
LATE WED NIGHT INTO THU WITH WINDS VEERING FROM NORTHWEST
IMMEDIATELY BEHIND THE FRONT TO NORTHEAST BY MID TO LATE MORNING
THU. OFFSHORE FLOW STARTS OUT AROUND 10 KT BUT COLD SURGE LATE THU
NIGHT WILL PUSH SPEEDS CLOSE TO 15 KT AWAY FROM SHORE. FRI COULD BE
QUITE INTERESTING IF THE 00Z ECMWF/HPC SOLUTION VERIFIES. THESE
SOLUTIONS BRING LOW PRESSURE...POTENTIALLY A TROPICAL HYBRID...INTO
THE COASTAL WATERS LATE FRI AND KEEPS IT IN THE AREA SAT. AT THIS
POINT THE EVENT LOOKS LIKE IT WOULD BE A SOLID SCA EVENT...AGAIN IN
THE 00Z ECMWF/HPC SOLUTION VERIFIES. THE 12Z GFS/CANADIAN HAS THE
LOW MUCH FARTHER OFF THE COAST WITH CONTINUED SOLID 15 KT NORTHEAST
FLOW SAT AND SUN. FOR NOW HAVE CONTINUED NORTHEAST FLOW THROUGH THE
END OF THE PERIOD WITH FURTHER ADJUSTMENTS EXPECTED AS THE CORRECT
SOLUTION BECOMES MORE DEFINED.
SEAS 2 TO 4 FT WITH SOME SWAN SUGGESTING A BIT OF SOUTHERLY SWELL
STARTING TO DEVELOP WED. PASSAGE OF COLD FRONT AND RESULTING
NORTHERLY FLOW WILL CREATE CHAOTIC 2 TO 4 FT SEAS WED NIGHT AND THU.
COLD SURGE THU NIGHT WILL INCREASE SEAS FRI...3 TO 4 FT EXCEPT FOR
AREAS BLOCKED TO NORTHEAST FLOW WHERE SEAS WILL BE 1 TO 2 FT.
&&
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...DCH
LONG TERM...III
AVIATION...RGZ/MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
303 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...SHOWERS REMAIN SCATTERED MAINLY OVER SOUTH
CAROLINA THIS AFTERNOON WHERE RICHER DEWPOINT AIR EXISTS WITH
READINGS IN THE MID 60S. DRIER AIR STILL EXISTS FROM CAPE FEAR
NORTH CLOSER TO THE COAST WHERE DEWPOINT TEMPS WERE IN THE MID
50S. HIGHER HRRR CAPE VALUES ALIGNING NICELY WITH SHWR DEVELOPMENT
OVER SC AND INLAND NC ZONES. CLOUD COVER MODERATING TEMPS
OVERALL...ESPECIALLY WHERE PCP OCCURRED THROUGH THE DAY.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
OVER SC MAINLY THROUGH LATE AFTERNOON WHILE COASTAL NC BECOMES
SLIGHTLY DRIER. MAIN AREA OF PCP MOVING UP THROUGH GA AND SC
AHEAD OF LOW TRACKING NORTH THROUGH TENNESSEE THROUGH TONIGHT.
DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND SOUTH CAROLINA
TRACKING INTO NC. PCP WATER VALUES WILL REACH UP AROUND 1.5 INCHES
INLAND WHILE STILL REMAINING QUITE DRY FROM CAPE FEAR NORTHWARD
WHERE PCP WATER VALUES REMAIN LESS THAN AN INCH CLOSER TO THE COAST.
EXPECT MOST OF THE SHWR ACTIVITY TO REMAIN SOUTH AND WEST OF CWA
WITH LESS IN THE WAY OF PCP ACROSS COASTAL NC THROUGH MUCH OF
TONIGHT. MOISTURE PROFILES OVER LOCAL AREA SHOWING MOISTURE
THINNING OUT THROUGH THE COLUMN IN THE MID LAYERS THROUGH THIS
EVENING. CAN NOT RULE OUT SOME SHWRS AS SHORTWAVE ROTATES AROUND
PROVIDING SOME MINOR PERTURBATIONS TO SUPPORT SOME CONVECTIVE
DEVELOPMENT BUT OVERALL EXPECT MORE ISOLATED THROUGH THIS EVENING
WITH BETTER CONVECTIVE DEVELOPMENT POSSIBLE LATER TONIGHT ACROSS
THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS THE COASTAL
WATERS.
TEMPS WILL ONLY DROP INTO THE LOWER 60S MOST PLACES OVERNIGHT WITH
PLENTY OF MOISTURE PRESENT AND CONSIDERABLE CLOUD COVER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...A WET SHORT TERM ON TAP AS A SLOW MOVING LOW
PRESSURE SYSTEM BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE
EASTERN CAROLINAS.
STILL UNCERTAINTY IN TIMING...BUT EXPECT SHOWERS TO BE ONGOING AT
THE START OF THE PERIOD...ESPECIALLY ACROSS THE WESTERN HALF OF THE
ILM CWA...AND BE IMPACTING THE ENTIRE AREA BY MONDAY AFTN. THESE
SHOWERS ARE DUE TO THE ADVANCE OF A SLOWLY MOVING LOW PRESSURE
SYSTEM SPAWNED BY IMPULSES ROTATING DOWN A DEEP...POSITIVELY TILTED
UPPER TROUGH DROPPING OUT OF THE MIDWEST. THE FIRST OF THESE
IMPULSES PUSHES INTO NEW ENGLAND LATE MONDAY AND TRAILS A COLD FRONT
INTO THE REGION. THIS FRONT GETS VERY LITTLE PUSH DUE TO THE
ORIENTATION OF UPPER FEATURES...AND BECOMES STALLED SOMEWHERE ACROSS
THE EASTERN MID-ATLANTIC AND SOUTHEAST. THIS BOUNDARY ACTS A
FOCUSING MECHANISM FOR CONTINUED ROUNDS OF HEAVY RAINFALL AND
THUNDERSTORMS THROUGH TUESDAY.
THE HEAVIEST RAINFALL WILL OCCUR MONDAY AFTN THROUGH TUESDAY
MORNING. THE COMBINATION OF SOME ENHANCED UPPER DIFLUENCE...PWATS
APPROACHING 1.75 INCHES (NEARLY 2 STD DEVIATIONS ABOVE
NORMAL)...RICH THETA-E AIR...10000 FT OF WARM CLOUD DEPTH...AND
CONVERGENCE ALONG THE STALLED BOUNDARY ALL POINT TOWARDS
WIDESPREAD SHOWERS/THUNDERSTORMS WITH HEAVY RAIN. ALTHOUGH BEST
MOISTURE TRANSPORT IS FOCUSED JUST NORTH OF THE ILM CWA...ENHANCED
MOIST ADVECTION FROM SE FLOW OFF THE GULF STREAM SHOULD PROVIDE
SOME HEAVIER RAIN. WILL BUMP POP TO CATEGORICAL MONDAY
AFTN/NIGHT...FALLING TO CHC BY TUE AFTN...WITH TOTAL QPF ABOVE 1
INCH POSSIBLE. WILL NOTE THAT ISOLATED HEAVIER TOTALS ARE
DEFINITELY POSSIBLE...SINCE DEEP SOUTHERLY FLOW BECOMES BOUNDARY
PERPENDICULAR...WHICH FAVORS TRAINING ECHOES FROM SOUTH TO NORTH
AS THE FRONT MAKES VERY LITTLE PROGRESS EASTWARD. SPC DOES HAVE
THE AREA IN A "SEE TEXT" FOR MONDAY...AND DECENT INSTABILITY WILL
EXIST AHEAD OF THE FRONT...BUT OTRW SEVERE PARAMETERS LOOK QUITE
WEAK AND EXPECT MORE OF A HEAVY RAIN THREAT THAN A SEVERE THREAT.
TEMPS WILL BE BELOW CLIMO MONDAY DUE TO CLOUDS AND RAIN...IN THE
UPPER 70S...WITH LOWS WELL ABOVE CLIMO ONLY FALLING INTO THE MID
60S. SIMILAR ON TUESDAY WITH CONTINUED CLOUDS AND SHOWERS...KEEPING
MAX TEMPS JUST BELOW CLIMO AROUND 80 AND MINS ONCE AGAIN FALLING
ONLY INTO THE LOW/MID 60S AT NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM SUNDAY...NEARLY STATIONARY FRONT WILL STILL BE OVER THE
AREA EARLY WEDNESDAY AS DEEP UPPER TROUGH AXIS MOVES OVERHEAD. THIS
WILL PROVIDE THE IMPETUS FOR CONTINUED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTNS OF WED AND THU. THE
KICKER NORTHERN STREAM S/W THEN DROPS SOUTHWARD OUT OF CANADA AND
FINALLY PUSHES THE COLD FRONT OFFSHORE THURSDAY. THIS ALLOWS THE
COLUMN TO BEGIN TO DRY OUT WITH SOME WEAK SUBSIDENCE BEHIND THE
DEPARTING TROUGH...BUT DIURNAL SHOWERS ARE STILL POSSIBLE FRI/SAT.
WILL CARRY CHC POP WED/THU WITH SCHC FRI/SAT...BUT THE ACTIVITY
FRI/SAT SHOULD BE MUCH MORE ISOLATED IN COVERAGE.
BOTH GFS AND EURO DEPICT THE UPPER TROUGH CUTTING OFF NEAR 70 WEST
AND SPAWNING A HYBRID-TYPE SURFACE LOW WELL OFFSHORE. THIS IS
FURTHER EAST THAN PREVIOUS RUNS AND MEANS LESS OF A RAIN CHANCE FOR
THE WKND THAN EARLIER GUIDANCE HAD SUGGESTED. FEEL NO REASON TO
CHANGE INHERITED SCHC ATTM.
TEMPS WILL REMAIN FAIRLY UNIFORM THROUGH THE EXTENDED...WITH HIGHS A
DEGREE OR SO BELOW CLIMO AND MINS AT NIGHT A DEGREE OR TWO ABOVE.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...A PERSISTENT AREA OF SHOWERS IS MOVING ONSHORE NEAR
GGE/MYR/CRE REACHING AS FAR INLAND AS LBT. FLIGHT CONDITIONS
ASSOCIATED WITH THIS AREA OF SHOWERS HAVE BEEN PREDOMINATELY
MVFR...BUT TEMPO PERIODS OF IFR HAVE OCCURRED. ELSEWHERE...FLO/LBT
HAS EXPERIENCED TEMPO PERIODS OF MVFR CEILINGS...WHILE ILM HAS
REMAINED VFR. SHOWERS WERE DEVELOPING SOUTH OF FLO.
TEMPO PERIODS OF SHOWERS/MVFR CONDITIONS WILL REMAIN POSSIBLE AT ALL
TERMINALS EXCEPT ILM THROUGH MID-LATE AFTERNOON. BY LATE
AFTERNOON/EARLY EVENING SHOWERS SHOULD BE AFFECTING MAINLY THE
FLO/LBT TERMINALS...ALTHOUGH SOME RESIDUAL SHOWERS FROM THE AREA
CURRENTLY NEAR MYR/CRE COULD AFFECT THE ILM TERMINAL BY THEN. EXPECT
ANY ACTIVITY NEAR ILM TO BE VERY LIGHT.
PRECIPITATION WILL BECOME VERY ISOLATED OR WILL END ALL-TOGETHER
DURING THE EVENING AS SIGNIFICANT LIFT DECREASES. THROUGH THE
OVERNIGHT HOURS PERIODS OF MVFR CAN BE EXPECTED. BY SUNRISE SHOWERS
WILL AGAIN INCREASE FROM THE SOUTHWEST WITH GOOD CHANCES OF
SHOWER/MVFR CONDITIONS DURING THE MORNING HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE PERIOD WITH A GOOD
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM SUNDAY...LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT THIS
MORNING BUT UP TO 4 FT JUST SOUTH AND EAST OF LOCAL WATERS. SOUTHEAST
WINDS UP AROUND 15 KTS WILL CONTINUE AS GRADIENT TIGHTENS BETWEEN
DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH PRESSURE WELL OFF
THE NORTH CAROLINA COAST. WINDS WILL VEER SLIGHTLY THROUGH TONIGHT
BECOMING MORE NORTHERLY AS LOW TRACKS FARTHER NORTH AND EAST. THIS
PERSISTENT ON SHORE FLOW THROUGH TONIGHT WILL BUILD SEAS UP TO 3
TO 4 FT WITH SOME 5 FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...REMAINING ISOLATED THROUGH MOST OF THE NIGHT WITH
POSSIBLE REDEVELOPMENT LATER TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...THE WATERS WILL BE SANDWICHED BETWEEN A VERY
SLOWLY ADVANCING COLD FRONT FROM THE WEST...AND HIGH PRESSURE
RETREATING TO THE EAST...THROUGH THE SHORT TERM. THIS CREATES
SOUTHERLY WINDS MONDAY...VEERING SLIGHTLY TO THE SW TUESDAY AS FRONT
GETS CLOSER TO THE AREA...AT 10-15 KTS THROUGHOUT. ALTHOUGH A WEAK
1FT/11SEC EASTERLY SWELL WILL EXIST IN THE WAVE SPECTRUM...THE
SIGNIFICANT WAVE HEIGHTS WILL BE FORCED PRIMARILY BY THE WIND...WITH
3-5 FT SEAS MONDAY FALLING TO 3-4 FT TUESDAY. ADDITIONALLY...THERE
IS A GOOD CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN TO IMPACT THE WATERS LATE MONDAY AND TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1244 PM EDT SUN MAY 13 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM APPROACHING FROM THE SOUTHWEST WILL BRING
INCREASING RAIN CHANCES THIS AFTERNOON AND TONIGHT. A COLD FRONT
WILL STALL NEAR THE AREA THROUGH MID WEEK BRINGING CONTINUED
CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH SIGNIFICANT RAINFALL
POSSIBLE MONDAY INTO TUESDAY. COLD FRONT PUSHES OFFSHORE THURSDAY
BRINGING DRIER CONDITIONS FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 12 PM SUNDAY...PCP ASSOCIATED WITH COASTAL TROUGH/WARM FRONT
SHIFTING NORTH AND DISSIPATING WHILE SHOWERS DEVELOPING IN WARM
SECTOR OVER SOUTH CAROLINA. DEWPOINT TEMPS IN THE MID 60S SOUTH
AND WEST OF BOUNDARY THROUGHOUT SC WHILE DEWPOINTS IN THE MID 50S
IN DRIER AIR FROM CAPE FEAR COAST NORTH. HIGHER HRRR CAPE VALUES
ALIGNING NICELY WITH SHWR DEVELOPMENT OVER SC AND INLAND NC ZONES.
MODELS STILL SHOWING SHWR DEVELOPMENT AREA SHIFTING FARTHER INLAND
THROUGH THIS AFTERNOON. CLOUD COVER MODERATING TEMPS OVERALL.
EXPECT HIGH TEMPS TO REACH INTO THE MID 70S MOST PLACES.
NAM SHOWS THIS BAND DIMINISHING WITH MAIN AREA OF PCP MOVING UP
THROUGH GA AND SC AHEAD OF LOW TRACKING INTO TENNESSEE THROUGH
THIS AFTERNOON. DEEPEST LAYER MOISTURE WILL REMAIN OVER INLAND
SOUTH CAROLINA TRACKING INTO NC THROUGH THE DAY. COLUMN WILL
MOISTEN OVER NC THROUGH THIS AFTERNOON BUT STILL REMAINS QUITE DRY
FROM CAPE FEAR NORTHWARD WHERE PCP WATER VALUES REMAIN LESS THAN
AN INCH. EXPECT MOST OF THE SHWRS TO DEVELOP OVER SC ZONES AND
WEST OF LOCAL CWA THROUGH MUCH OF TONIGHT.
GUSTY SOUTHEASTERLY FLOW WILL CONTINUE AT THE SURFACE AS GRADIENT
TIGHTENS BETWEEN DEVELOPING LOW PRESSURE MOVING UP THROUGH
TENNESSEE AND HIGH PRESSURE OFF SHORE. THIS WARM MOIST ON SHORE
FLOW WILL KEEP DEWPOINT TEMPS INTO THE 60S...BUT LESS FROM CAPE
FEAR COAST NORTHWARD WHERE SLIGHTLY DRIER AIR EXISTS.
FROM PREVIOUS DISCUSSION...THERE SHOULD BE A LULL IN THE COVERAGE OF
PRECIPITATION ACROSS THE EASTERN CAROLINAS LATE THIS AFTERNOON
INTO THE EVENING HOURS. REDEVELOPMENT OF SHOWERS IS THEN EXPECTED
LATE ACROSS THE PEE DEE REGION IN SOUTH CAROLINA AND ALSO ACROSS
THE COASTAL WATERS. ALTHOUGH FORECAST SOUNDINGS SHOW NO INVERSION
LAYERS ALOFT TO INHIBIT CONVECTION...ENVIRONMENTAL LAPSE RATES
NEAR MOIST ADIABATIC WILL NOT PROMOTE DEEP CONVECTION UNTIL BETTER
SYNOPTIC FORCING ARRIVES ON MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...A WET SHORT TERM ON TAP AS A SLOW MOVING LOW
PRESSURE SYSTEM BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE
EASTERN CAROLINAS.
STILL UNCERTAINTY IN TIMING...BUT EXPECT SHOWERS TO BE ONGOING AT
THE START OF THE PERIOD...ESPECIALLY ACROSS THE WESTERN HALF OF THE
ILM CWA...AND BE IMPACTING THE ENTIRE AREA BY MONDAY AFTN. THESE
SHOWERS ARE DUE TO THE ADVANCE OF A SLOWLY MOVING LOW PRESSURE
SYSTEM SPAWNED BY IMPULSES ROTATING DOWN A DEEP...POSITIVELY TILTED
UPPER TROUGH DROPPING OUT OF THE MIDWEST. THE FIRST OF THESE
IMPULSES PUSHES INTO NEW ENGLAND LATE MONDAY AND TRAILS A COLD FRONT
INTO THE REGION. THIS FRONT GETS VERY LITTLE PUSH DUE TO THE
ORIENTATION OF UPPER FEATURES...AND BECOMES STALLED SOMEWHERE ACROSS
THE EASTERN MID-ATLANTIC AND SOUTHEAST. THIS BOUNDARY ACTS A
FOCUSING MECHANISM FOR CONTINUED ROUNDS OF HEAVY RAINFALL AND
THUNDERSTORMS THROUGH TUESDAY.
THE HEAVIEST RAINFALL WILL OCCUR MONDAY AFTN THROUGH TUESDAY
MORNING. THE COMBINATION OF SOME ENHANCED UPPER DIFLUENCE...PWATS
APPROACHING 1.75 INCHES (NEARLY 2 STD DEVIATIONS ABOVE
NORMAL)...RICH THETA-E AIR...10000 FT OF WARM CLOUD DEPTH...AND
CONVERGENCE ALONG THE STALLED BOUNDARY ALL POINT TOWARDS
WIDESPREAD SHOWERS/THUNDERSTORMS WITH HEAVY RAIN. ALTHOUGH BEST
MOISTURE TRANSPORT IS FOCUSED JUST NORTH OF THE ILM CWA...ENHANCED
MOIST ADVECTION FROM SE FLOW OFF THE GULF STREAM SHOULD PROVIDE
SOME HEAVIER RAIN. WILL BUMP POP TO CATEGORICAL MONDAY
AFTN/NIGHT...FALLING TO CHC BY TUE AFTN...WITH TOTAL QPF ABOVE 1
INCH POSSIBLE. WILL NOTE THAT ISOLATED HEAVIER TOTALS ARE
DEFINITELY POSSIBLE...SINCE DEEP SOUTHERLY FLOW BECOMES BOUNDARY
PERPENDICULAR...WHICH FAVORS TRAINING ECHOES FROM SOUTH TO NORTH
AS THE FRONT MAKES VERY LITTLE PROGRESS EASTWARD. SPC DOES HAVE
THE AREA IN A "SEE TEXT" FOR MONDAY...AND DECENT INSTABILITY WILL
EXIST AHEAD OF THE FRONT...BUT OTRW SEVERE PARAMETERS LOOK QUITE
WEAK AND EXPECT MORE OF A HEAVY RAIN THREAT THAN A SEVERE THREAT.
TEMPS WILL BE BELOW CLIMO MONDAY DUE TO CLOUDS AND RAIN...IN THE
UPPER 70S...WITH LOWS WELL ABOVE CLIMO ONLY FALLING INTO THE MID
60S. SIMILAR ON TUESDAY WITH CONTINUED CLOUDS AND SHOWERS...KEEPING
MAX TEMPS JUST BELOW CLIMO AROUND 80 AND MINS ONCE AGAIN FALLING
ONLY INTO THE LOW/MID 60S AT NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM SUNDAY...NEARLY STATIONARY FRONT WILL STILL BE OVER THE
AREA EARLY WEDNESDAY AS DEEP UPPER TROUGH AXIS MOVES OVERHEAD. THIS
WILL PROVIDE THE IMPETUS FOR CONTINUED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTNS OF WED AND THU. THE
KICKER NORTHERN STREAM S/W THEN DROPS SOUTHWARD OUT OF CANADA AND
FINALLY PUSHES THE COLD FRONT OFFSHORE THURSDAY. THIS ALLOWS THE
COLUMN TO BEGIN TO DRY OUT WITH SOME WEAK SUBSIDENCE BEHIND THE
DEPARTING TROUGH...BUT DIURNAL SHOWERS ARE STILL POSSIBLE FRI/SAT.
WILL CARRY CHC POP WED/THU WITH SCHC FRI/SAT...BUT THE ACTIVITY
FRI/SAT SHOULD BE MUCH MORE ISOLATED IN COVERAGE.
BOTH GFS AND EURO DEPICT THE UPPER TROUGH CUTTING OFF NEAR 70 WEST
AND SPAWNING A HYBRID-TYPE SURFACE LOW WELL OFFSHORE. THIS IS
FURTHER EAST THAN PREVIOUS RUNS AND MEANS LESS OF A RAIN CHANCE FOR
THE WKND THAN EARLIER GUIDANCE HAD SUGGESTED. FEEL NO REASON TO
CHANGE INHERITED SCHC ATTM.
TEMPS WILL REMAIN FAIRLY UNIFORM THROUGH THE EXTENDED...WITH HIGHS A
DEGREE OR SO BELOW CLIMO AND MINS AT NIGHT A DEGREE OR TWO ABOVE.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
AS OF 12Z...SHOWERS MOVING ONSHORE NEAR MYR WILL PRODUCE AT LEAST
MVFR CONDITIONS AT MYR/CRE THROUGH 14-16Z. THE CHANCE OF IFR
CONDITIONS IS LOW...BUT IF IT DOES OCCUR IT WOULD BE VERY BRIEF AND
ASSOCIATED WITH THE ISOLATED MODERATE SHOWERS AT MYR/CRE. THIS
SHOWER ACTIVITY WILL BE MOVING FURTHER INLAND ON SOUTHEASTERLY WINDS
STAYING EAST OF FLO...BUT EVENTUALLY AFFECTING THE LBT TERMINAL BY
14Z WITH THE CHANCE OF AT LEAST TEMPO MVFR CONDITIONS. THROUGH
THIS AFTERNOON THE BEST CHANCE OF SHOWERS/MVFR CONDITIONS WILL BE
AT BOTH THE FLO/LBT TERMINALS...WITH LESSER CHANCES OF PRECIPITATION
AND HIGHER CHANCES OF VFR AT THE COASTAL TERMINALS. BUT BY LATE
AFTERNOON THE BEST CHANCE OF PRECIPITATION/MVFR CONDITIONS WILL
SHIFT TO THE COASTAL TERMINALS BEFORE BECOMING VERY ISOLATED OR
ENDING ALL-TOGETHER DURING THE EVENING AS SIGNIFICANT LIFT
DECREASES. THROUGH THE REMAINDER OF THE TAF VALID PERIOD PERIODS
OF MVFR CAN BE EXPECTED. THE CHANCE OF ANY IFR IS LOW.
EXTENDED OUTLOOK...UNSETTLED WEATHER MONDAY THROUGH THE PERIOD WITH
A GOOD CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12 PM SUNDAY...SHOWERS ALONG THE SC COAST WILL CONTINUE
THROUGH MUCH OF THE MORNING AND IN A MORE LIMITED EXTENT INTO THE
EARLY AFTERNOON AS WELL. LATEST BUOY OBS SHOWING SEAS 2 TO 3 FT
THIS MORNING. GUSTY SOUTHEAST WINDS WILL CONTINUE AS GRADIENT
TIGHTENS BETWEEN DEVELOPING LOW PRESSURE OVER TENNESSEE AND HIGH
PRESSURE WELL OFF THE NORTH CAROLINA COAST. WINDS WILL VEER
SLIGHTLY THROUGH TONIGHT BECOMING MORE NORTHERLY AS LOW TRACKS
FARTHER NORTH AND EAST. THIS PERSISTENT ON SHORE FLOW UP AROUND 15
KTS THROUGH TONIGHT WILL BUILD SEAS UP TO 3 TO 4 FT WITH SOME 5
FTERS IN OUTER WATERS.
THE BEST CHANCE OF SHOWER ACTIVITY WILL REMAIN ACROSS THE SC
WATERS...BECOMING MORE ISOLATED IN NATURE THIS AFTERNOON. MODELS
SHOW REDEVELOPMENT OF SHOWERS POSSIBLE LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...THE WATERS WILL BE SANDWICHED BETWEEN A VERY
SLOWLY ADVANCING COLD FRONT FROM THE WEST...AND HIGH PRESSURE
RETREATING TO THE EAST...THROUGH THE SHORT TERM. THIS CREATES
SOUTHERLY WINDS MONDAY...VEERING SLIGHTLY TO THE SW TUESDAY AS FRONT
GETS CLOSER TO THE AREA...AT 10-15 KTS THROUGHOUT. ALTHOUGH A WEAK
1FT/11SEC EASTERLY SWELL WILL EXIST IN THE WAVE SPECTRUM...THE
SIGNIFICANT WAVE HEIGHTS WILL BE FORCED PRIMARILY BY THE WIND...WITH
3-5 FT SEAS MONDAY FALLING TO 3-4 FT TUESDAY. ADDITIONALLY...THERE
IS A GOOD CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN TO IMPACT THE WATERS LATE MONDAY AND TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...VERY SLOWLY MOVING COLD FRONT WILL WAVER
ACROSS THE WATERS WEDNESDAY AND MAY TURN WINDS BRIEFLY TO THE WEST
EARLY WEDNESDAY BEFORE BACKING TO THE SW ONCE AGAIN MUCH OF THE DAY.
WITH THE FRONT NEARLY OVERHEAD...WINDS WILL BE RATHER LIGHT...5-10
KTS...BUT WITH LACK OF ANY MEANINGFUL SWELL PRESENT THE SEAS WILL
STILL BE MOSTLY WIND CHOP...AT 2-4 FT. LATE WED NIGHT FROPA FINALLY
OCCURS ACROSS THE WATERS AND WINDS TURN TO THE NW...THEN NE ON
THURSDAY...WITH A DECENT NE SURGE DEVELOPING THURSDAY NIGHT. WINDS
OF 5-10 KTS WILL INCREASE FROM THE NE...BECOMING 10-15 KTS LATE
THURSDAY. AFTER A PERIOD OF CONFUSED SEAS WITH THE WIND SHIFT...NE
WIND WAVES WILL BUILD BACK UP TO 3-4 FT EXCEPT IN THE SHADOWED
REGION SW OF FRYING PAN SHOALS WHERE 1-2 FT SEAS WILL PERSIST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS AMARILLO TX
332 PM CDT SUN MAY 13 2012
.DISCUSSION...
PRIMARY FOCUS IS ON PRECIPITATION CHANCES THROUGH MONDAY.
AFTERNOON WATER VAPOR IMAGERY SHOWED A MID/UPPER-LEVEL SHORTWAVE
TROUGH SINKING SOUTHEAST ACROSS EASTERN UT TOWARDS THE FOUR CORNERS
REGION. MID TO UPPER-LEVEL FORCING AHEAD OF THIS SHORTWAVE HAS
COMBINED WITH DAYTIME HEATING/DESTABILIZATION AND LOW-LEVEL UPSLOPE
FLOW OVER EASTERN CO AND NM TO GENERATE SHOWERS AND THUNDERSTORMS.
THE GREATEST CONVECTIVE COVERAGE IS CURRENTLY ACROSS NORTHEAST NM
WORKING INTO THE SOUTHWEST TX PANHANDLE...BUT ADDITIONAL SCATTERED
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED FARTHER EAST ACROSS THE
PANHANDLES DUE TO THE COMBINATION OF AFTERNOON DESTABILIZATION AND
BROADER SCALE LIFT AHEAD OF THE SHORTWAVE.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE AREA THIS
EVENING AND OVERNIGHT. THE MID/UPPER-LEVEL SHORTWAVE TROUGH WILL
CONTINUE TO DIVE SOUTHEAST...REACHING NORTHERN/CENTRAL NM BY EARLY
MONDAY MORNING. DIFFLUENT/DIVERGENT FLOW ALOFT AHEAD OF THIS WAVE
WILL CONTINUE TO SUPPORT CONVECTION PROPAGATING EAST/SOUTHEAST OUT OF
NM AND CO THIS EVENING AND OVERNIGHT. BEST DYNAMICS WILL BE FOCUSED
ACROSS THE SOUTHWEST HALF OF THE AREA AND HAVE ALIGNED POPS
ACCORDINGLY. ALSO SOME WEAK ISENTROPIC LIFT EVIDENT ON THE 305K THETA
SURFACE ACROSS THE SOUTHWEST TX PANHANDLE THIS EVENING TO FURTHER AID
CONVECTION. LATEST LAPS AND RUC ANALYSIS DATA SHOW MLCAPES IN THE
500-1000 J/KG RANGE ACROSS THE WESTERN PANHANDLES WITH LESSER VALUES
TO THE EAST AND DEEP LAYER SHEAR AROUND 30-35 KTS IN THE SOUTHWEST
TX PANHANDLE...DECREASING TO THE NORTHEAST. THUS COULD SEE A FEW
STRONG STORMS THROUGH THIS EVENING CAPABLE OF PRODUCING SMALL HAIL
AND GUSTY WINDS...BUT NOT REALLY ANTICIPATING ANY SEVERE WEATHER
/ALTHOUGH AN ISOLATED MARGINALLY SEVERE STORM ACROSS THE SOUTHWEST CAN/T
BE RULED OUT/. COULD ALSO SEE SOME LOCALLY HEAVY RAIN GIVEN PWATS IN
THE THREE QUARTERS OF AN INCH TO ONE INCH RANGE AND SOME TRAINING OF
STORMS POSSIBLE. BETTER RAIN CHANCES LOOK TO GRADUALLY SHIFT
SOUTH/SOUTHWEST OF THE AREA LATE TONIGHT IN ASSOCIATION WITH STRONGER
DIVERGENCE ALOFT...AND ALSO AS THE LLJ AND LOW-LEVEL ISENTROPIC LIFT
FOCUS TO OUR SOUTHWEST.
RAIN CHANCES LINGER INTO MONDAY...BUT WILL GRADUALLY END FROM NORTH
TO SOUTH THROUGH THE DAY AS THE SHORTWAVE CONTINUES TO DIVE SOUTHEAST
TO SOUTHEAST NM/SOUTHWEST TX BY EARLY MONDAY EVENING. BETTER RAIN
CHANCES WILL BE FOCUSED ACROSS THE SOUTHERN HALF OF THE CWA ON
MONDAY. WEAKER INSTABILITY AND SHEAR SHOULD PRECLUDE ANY STRONG OR
SEVERE STORMS. WILL ALSO SEE THE COOLEST TEMPS IN THE SOUTH ON MONDAY
DUE TO LINGERING CLOUDS/PRECIP...WITH HIGHS FORECAST TO RANGE FROM
THE UPPER 60S SOUTHWEST TO MID/UPPER 70S NORTH.
DRY CONDITIONS ARE THEN FORECAST BEGINNING MONDAY NIGHT AS SHORTWAVE
UPPER RIDGING BUILDS EAST ACROSS THE SOUTHERN AND CENTRAL ROCKIES.
TEMPS WILL BEGIN TO REBOUND ON TUESDAY DUE TO RISING HEIGHTS...A
RETURN OF WEAK SOUTHERLY WINDS...AND INCREASED SUNSHINE...WITH HIGHS
CLIMBING BACK INTO THE UPPER 70S TO LOWER 80S. A DAMPENING MID-LEVEL
SHORTWAVE WILL WORK ACROSS THE CENTRAL ROCKIES AND PLAINS WEDNESDAY
AND WEDNESDAY NIGHT. THIS COULD POTENTIALLY SPAWN A FEW
SHOWERS/THUNDERSTORMS ACROSS THE NORTHERN PANHANDLES WEDNESDAY NIGHT.
HOWEVER...CHANCES LOOK LOW AT THIS TIME AS BETTER DYNAMICS WILL STAY
TO OUR NORTH AND COME ACROSS AT NIGHT...BY WHICH TIME ELEVATED
INSTABILITY LOOKS MINIMAL. THUS KEPT A DRY FORECAST FOR NOW. THE LEE
TROUGH WILL DEEPEN ON WEDNESDAY...WITH RESULTANT BREEZY SOUTHWEST
WINDS FURTHER CONTRIBUTING TO THE WARM UP.
A ZONAL FLOW/BROAD FLAT RIDGING LATE THIS WEAK WILL TRANSITION TO
SOUTHWESTERLY OVER THE WEEKEND AS AN UPPER TROUGH WORKS ACROSS THE
INTERMOUNTAIN WEST AND ROCKIES EVENTUALLY INTO THE NORTHERN PLAINS.
THIS FLOW ALOFT WILL PROMOTE SURFACE LEE TROUGHING AND SOME
SHARPENING OF THE DRYLINE BY FRIDAY AND SATURDAY. HOWEVER IT
CURRENTLY LOOKS LIKE WARM TEMPS ALOFT AND A LACK OF UPPER FORCING /AS
THE TROUGH IS DEFLECTED WELL TO OUR NORTHWEST/ WILL MAKE IT TOUGH FOR
CONVECTION TO INITIATE. THUS WILL MAINTAIN A DRY FORECAST. ABOVE
NORMAL TEMPERATURES EXPECTED LATE WEEK INTO THE WEEKEND WITH HIGHS IN
THE MID 80S TO LOWER 90S. WILL HAVE TO KEEP AN EYE ON A POTENTIAL
COLD FRONT THAT MAY MOVE IN SUNDAY OR SUNDAY NIGHT.
KB
&&
.FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE CURRENTLY
EXPECTED THROUGH THE WEEK. SOUTH/SOUTHWEST WINDS WILL INCREASE TO 15
TO 20 MPH ON WEDNESDAY AND RELATIVE HUMIDITIES MAY FALL TO 15 TO 20
PERCENT ACROSS THE FAR WESTERN PANHANDLES...BUT RECENT RAINFALL AND
RESULTANT GREEN-UP SHOULD MITIGATE ANY FIRE WEATHER CONCERNS. WARMER
TEMPERATURES WILL CONTINUE LATE WEEK INTO THE WEEKEND AND MINIMUM
RELATIVE HUMIDITIES WILL FALL TO 15 TO 20 PERCENT ACROSS WESTERN
AREAS. SOUTH/SOUTHWEST WINDS WILL BE BREEZY AT TIMES AND ELEVATED
FIRE WEATHER CONDITIONS COULD DEVELOP...BUT AGAIN RECENT RAINFALL AND
GREEN-UP WILL HELP MINIMIZE FIRE WEATHER CONCERNS.
KB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 50 69 50 79 53 / 70 40 10 0 0
BEAVER OK 50 76 51 83 53 / 20 10 5 0 0
BOISE CITY OK 48 73 48 81 51 / 50 20 5 0 0
BORGER TX 52 75 54 82 57 / 50 40 5 0 0
BOYS RANCH TX 52 72 51 82 55 / 70 40 5 0 0
CANYON TX 50 68 48 79 51 / 70 40 10 5 0
CLARENDON TX 53 70 52 79 55 / 50 40 10 5 0
DALHART TX 48 71 46 80 50 / 70 40 5 0 0
GUYMON OK 50 76 50 84 53 / 30 20 5 0 0
HEREFORD TX 49 68 47 78 51 / 80 50 10 5 0
LIPSCOMB TX 50 75 49 81 52 / 20 20 5 0 0
PAMPA TX 50 70 50 79 54 / 40 40 5 0 0
SHAMROCK TX 53 74 51 80 54 / 40 30 10 5 0
WELLINGTON TX 55 75 54 81 55 / 40 30 10 5 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
07/08
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1134 AM MDT SUN MAY 13 2012
.AVIATION...
ISOLATED SHOWERS AND THUNDERSTORMS TO CONTINUE OVER THE SNOWY AND
SIERRA RANGES INTO THIS AFTERNOON. SUBSIDENCE STARTING TO SET IN
BEHIND A SHORTWAVE DIVING SOUTH ACROSS EASTERN UTAH. SUBSIDENCE
WILL BRING AN END TO THE CONVECTION BY 00Z THIS EVENING IF NOT
SEVERAL HOURS EARLIER. OTHERWISE ONLY EXPECTING FEW TO SCATTERED
CUMULUS IN SOUTHERN PORTIONS OF THE FORECAST AREA THROUGH THIS
AFTERNOON...THEN CLEAR SKIES AND LIGHT WINDS TONIGHT WITH SURFACE
HIGH PRESSURE IN PLACE AND BUILDING UPPER LEVEL RIDGE. LIGHT WINDS
AND CLEAR SKIES EXPECTED THROUGH MONDAY AND TUESDAY ALTHOUGH WINDS
SPEEDS WILL PICK UP SOMEWHAT TUESDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 917 AM MDT SUN MAY 13 2012/
UPDATE...UPDATED FORECAST TO EXPIRE THE DENSE FOG ADVISORY THIS
MORNING SINCE THE FOG HAS LIFTED ACROSS MOST OF THE AREA. THE
REMAINDER OF THE FORECAST TODAY AND TONIGHT LOOKS ON TRACK WITH
ISOLATED TO WIDELY SCATTERED SHOWERS AND TSTORMS POSSIBLE SOUTH OF
I80 THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 619 AM MDT SUN MAY 13 2012/
UPDATE...
AVIATION...12Z TAFS
IFR TO LIFR CONDITIONS FROM KLAR EAST TO KSNY...AND ON UP TO KAIA
WILL CONTINUE THRU 13 OR 14Z UNTIL MIXING DISSIPATES THE FOG.
VSBYS SHOULD QUICKLY IMPROVE TO VFR THEREAFTER...AND WILL REMAIN
SO FOR THE REMAINDER OF THE TAF PERIOD ACROSS THE FORECAST AREA.
ISOLATED SHOWERS AND TSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING IN THE SOUTHERN MOUNTAINS AND VICINITY AS NORTHEAST SFC
FLOW COMBINES WITH LINGERING MIDLEVEL ENERGY FROM A SHORTWAVE
TROUGH OVERHEAD. KEPT VCTS AT KLAR AND KCYS THIS AFTERNOON AS THE
CHANCE FOR TSRA MOVING OVER THE AIRFIELD WILL BE LOW HERE. WINDS
WILL REMAIN LIGHT OVERALL AND WILL BECOME SOUTHERLY TONIGHT. ONCE
THE FOG LIFTS THIS MORNING...SKIES SHOULD REMAIN VFR THROUGH THE
REMAINDER OF THE PERIOD.
PREV DISCUSSION... /ISSUED 408 AM MDT SUN MAY 13 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
EARLY MORNING DENSE FOG WILL BE THE INITIAL FORECAST CONCERN
TODAY. SATELLITE FOG PRODUCT DEPICTS THE AREA OF DENSE FOG WAS
EXPANDING ACROSS CENTRAL AND WESTERN LARAMIE COUNTY EARLY THIS
MORNING. MEANWHILE...VISIBILITIES HAVE DECREASED TO 1/4SM AT BOTH
KLAR AND KCYS. 00Z NAM/GFS OUTPUT WAS WEAK ON BOUNDARY LAYER
MOISTURE/SATURATION THIS MORNING. SO HAVE FAVORED 07Z RUC DATA
WHICH HANDLED THE BOUNDARY LAYER MOISTURE MUCH BETTER. IN ADDITION
TO INSULATION...MIXING WILL INCREASE WITH THE APPROACH AND PASSAGE
OF A POSITIVELY TILTED SHORTWAVE THIS MORNING. THUS EXPECT FOG TO
DISSIPATE BY AROUND 15Z. HAVE OPTED TO HOIST A DENSE FOG ADVISORY
FOR AREAS FROM LARAMIE THROUGH CHEYENNE IN EFFECT THROUGH 15Z THIS
MORNING.
00Z MODEL OUTPUT WAS FASTER IN MOVING THE AFOREMENTIONED
SHORTWAVE SOUTH OF THE CWA COMPARED TO YESTERDAY. THIS WILL MOVE
A DRIER AIR MASS INTO THE CWA EARLIER A BIT EARLIER
TODAY...LIMITING CONVECTION POSSIBILITIES ACROSS SE WYOMING.
PROGD SOUNDINGS FOR AREAS NR THE STATELINE STILL INDICATE WEAK
INSTABILITY THIS AFTERNOON...SO CANT RULE OUT A FEW SHOWERS
AND/OR WEAK THUNDERSTORMS. HOWEVER WOULD EXPECT MOST OF THE
ACTIVITY TO REMAIN SOUTH IN COLORADO. TEMPERATURES WILL BE 5 TO
10 DEGREES WARMER TODAY...WITH HIGHS THAT WILL REACH INTO THE 60S
AND LOW 70S.
LARGE SCALE SUBSIDENCE BENEATH A BUILDING MID/UPPER-LEVEL RIDGE
WILL KEEP CONDITIONS DRY FOR MONDAY AND TUESDAY. H7 TEMPERATURES
WILL CLIMB TO 8-10C BOTH DAYS...WHICH WILL YIELD HIGH TEMPERATURES
THAT WILL CLIMB WELL INTO THE 70S...WITH 80S ON THE EASTERN
PLAINS.
LONG TERM...WEDNESDAY THROUGH SUNDAY...BROAD UPPER LEVEL RIDGE
WILL BE OVER MUCH OF THE US ON WEDNESDAY WITH A WEAK SHORTWAVE
MOVING THROUGH THE RIDGE AND ACROSS THE CENTRAL ROCKIES. GFS AND
ECMWF DO NOT BRING MUCH DEEP LAYER MOISTURE ALONG WITH THIS
FEATURE...SO KEPT LOW CHANCES FOR SHOWERS AND THUNDERSTORMS FIRST
IN OROGRAPHIC FAVORED AREAS IN THE AFTERNOON THEN SHIFTING EAST
THROUGH THE EVENING AS A PACIFIC FRONT MOVES ON THROUGH. BREEZY
WEST WINDS WILL OCCUR BEHIND THE FRONT AS WELL. THIS FEATURE AND
ASSOCIATED MOISTURE WILL MOVE TO THE EAST ON THURSDAY WITH THE
RIDGE STILL IN CONTROL OVER THE CENTRAL US. SO EXPECTING VERY WARM
AND DRY CONDITIONS FOR THURSDAY WITH GENERALLY LIGHT SOUTHERLY
WINDS. A SHORTWAVE TROUGH WILL APPROACH FROM THE WEST ON FRIDAY
BUT MODELS ARE HAVING DIFFICULTY HANDLING THIS SYSTEM. ECMWF TENDS
TO PRODUCE A WEAK CUTOFF LOW OVER CALIFORNIA AND NEVADA WHILE GFS
KEEPS A FAST MOVING OPEN WAVE THROUGH THE WEEKS END. INITIAL DRY
SLOTTING AHEAD OF THE WAVE WILL KEEP THE AREA MOSTLY DRY FOR
FRIDAY...WITH INCREASED CHANCES FOR RAIN AND AFTERNOON THUNDER
THROUGH THE WEEKEND AS THIS WAVE MOVES ACROSS THE ROCKIES AND
BRINGS ANOTHER PACIFIC FRONT ALONG WITH IT. AGAIN...UNSURE OF
EXACT TIMING SO KEPT POPS FAIRLY LOW FOR THE WEEKEND. MAX TEMPS
WILL PEAK IN THE UPPER 70S OUT WEST TO UPPER 80S AND LOW 90S
ACROSS THE EASTERN PLAINS FOR THURSDAY AND FRIDAY...WITH A 10 TO
15 DEGREE DROP IN TEMPS EXPECTED FOR THE WEEKEND BEHIND THE
PACIFIC FRONT. ONCE AGAIN...PACIFIC MOISTURE LOOKS QUITE THIN WITH
THIS SYSTEM WITH THE DEEPER PLUME SHUNTED OFF TO THE NORTH. BUT
WILL KEEP THE LOW CHANCES FOR RAIN AND AFTERNOON THUNDER THROUGH
THE WEEKEND...ESPECIALLY AS SFC FLOW SWITCHES TO THE EAST BEHIND
THE FRONT AND ADDS THE UPSLOPE COMPONENT TO HELP TRIGGER
CONVECTION.
FIRE WEATHER... FOG WILL DISSIPATE ACROSS SOUTHEAST WYOMING BY
MID-MORNING. A FEW ISOLATED SHOWERS AND WEAK THUNDERSTORMS WILL BE
POSSIBLE TODAY FOR AREAS OF THE DISTRICT NEAR THE COLORADO
STATELINE. A DRIER AND WARMER AIR MASS WILL MOVE IN FOR EARLY NEXT
WEEK...WITH HIGHS RETURNING BACK INTO THE 70S WEST AND 80S EAST.
MINIMUM RELATIVE HUMIDITIES WILL DROP BACK INTO THE 10 TO 20
PERCENT RANGE ON MONDAY THROUGH THURSDAY. FORTUNATELY WINDS WILL
ONLY PEAK AT AROUND 10 TO 15 MPH EACH AFTERNOON. FRIDAY LOOKS
BREEZIER WITH LOW RELATIVE HUMIDITIES CONTINUING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...TJT
LONG TERM/AVIATION...LIEBL