Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/10/13
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
858 PM CDT THU MAY 9 2013
.UPDATE...
CONVECTION CONTINUES OVER THE SOUTH AT THIS TIME AS UPPER LEVEL
ENERGY APPROACHES FROM TEXAS. OTHER WEAKER CONVECTION ACROSS THE
NORTH IS WORKING OVER THE SAME GENERAL AREA THAT SAW SOME
THUNDERSTORMS THIS MORNING. ACTIVITY HAS BEEN SLOWLY WEAKENING BUT
POTENTIAL REMAINS FOR SOME LARGER HAIL THROUGH THE NIGHT.
SOME STORMS LIKELY WILL PRODUCE BRIEF HEAVY DOWNPOURS BUT NO
HEADLINES ARE ANTICIPATED AT THIS TIME. AFOREMENTIONED WAVE STILL
OVER NORTHEAST TEXAS AND HAS TO ROTATE THROUGH THE STATE TONIGHT
AND WILL KEEP POPS ON THE HIGH SIDE AS A RESULT.
ATTENTION WILL ALSO DIRECTED TOWARDS THE AFOREMENTIONED COLD
FRONT CURRENTLY STRETCHING FROM CENTRAL OKLAHOMA THROUGH CENTRAL
MISSOURI. THE BOUNDARY WILL BE A SLOW MOVER AND WILL ONLY REACH
FAR NORTHWEST ARKANSAS BY MORNING KEEPING POPS ELEVATED ACROSS
THIS PART OF THE STATE AS WELL.
EVENING UPDATE WILL BE TO REWORK POPS AND QPF BASED ON CURRENT
RADAR TRENDS AND A QUICK PEEK AT THE NEW NAM AND THE HRRR MODELS.
ALL UPDATES OUT.
&&
.PREV DISCUSSION... /ISSUED 654 PM CDT THU MAY 9 2013/
AVIATION...
A STATIONARY FRONT IS ACROSS NORTHEAST AND CENTRAL OKLAHOMA. THIS
FRONT WILL MOVE EAST LATE TONIGHT AND WILL BE IN WESTERN ARKANSAS
BY MORNING...AND TO EASTERN ARKANSAS BY FRIDAY EVENING. SHOWERS
AND THUNDERSTORMS HAVE ALREADY DEVELOPED OVER WESTERN ARKANSAS AND
WILL CONTINUE TO MOVE EAST TONIGHT. VFR CONDITIONS WILL BECOME
MVFR AND IFR DURING THE NIGHT. CONDITIONS WILL IMPROVE FRIDAY
MORNING AS THE STORMS MOVE EAST.
PREV DISCUSSION... /ISSUED 305 PM CDT THU MAY 9 2013/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
CONVECTION THAT AFFECTED PARTS OF THE AREA THIS MRNG...HAD SHIFTED E
OF THE REGION BY MIDDAY. SUBSIDENCE BEHIND THIS ACTIVITY HAS LIMITED
ADDITIONAL FORMATION ACRS AR THRU MID AFTN. IT ALSO ALLOWED CLOUDS
TO DCRS OVR MUCH OF NRN AND ERN AR...WITH MID AFTN TEMPS IN THE UPR
70S TO LOWER 80S. INCRSG CLOUDS OVR SWRN AR HELD READINGS IN THE
LOWER AND MID 70S. WL KEEP MINIMAL POPS OVR MOST OF THE FA EARLY
THIS EVENING.
MEANWHILE...A COMPLEX OF STORMS CONTD TO ORGANIZE ACRS CNTRL/ERN TX
THIS AFTN...ASSOCD WITH ANOTHER UPR LVL WV MOVG ACRS THE SRN PLAINS.
AN ADDITIONAL CLUSTER OF STORMS HAS FORMED ALONG THE RED RVR IN SERN
OK. EXPECT SOME THIS ACTIVITY TO AFFECT WRN AR TOWARD SUNSET.
ADDITIONAL CONVECTION WL FORM TNGT AS THE AFOREMENTIONED UPR IMPULSE
TRACKS INTO AR...AND ALONG A SLOW MOVG CDFNT APCHG FM THE CNTRL
PLAINS. CURRENT DATA SUGGESTS THE BNDRY WL BE ALONG THE I-44
CORRIDOR EARLY FRI MRNG. CANNOT RULE OUT A FEW STRONG/SVR STORMS
TNGT...WITH LARGE HAIL AND WINDS THE MAIN CONCERNS.
APPEARS WE WL SEE A LULL IN THE RAINFALL LATER FRI MRNG/EARLY AFTN
AS THE FIRST ROUND OF STORMS WORKS E OF THE AREA. THE CDFNT WL CONT
TO DRIFT EVER SO SLOLY SEWD INTO CNTRL AR LATER ON FRI AS THE BNDRY
INITIALLY ENCOUNTERS SWLY FLOW ALOFT. SCTD SHRA/TSRA WL BE POSSIBLE
AHEAD OF THE FNT INTO FRI NGT. RAIN CHCS WL DCRS FM THE NW AS THE
NGT PROGRESSES AND THE FNT SHIFTS SE OF AR.
DRIER CONDS RETURN FOR SAT WITH TEMPS CLOSE TO NORMAL FOR THIS TIME
OF YEAR. A SECONDARY CDFNT WL SWEEP SWD THRU AR SAT NGT...FOLLOWED
BY COOLER AND MUCH DRIER AIR. AN UPR LVL IMPULSE IS PROGGED TO DROP
SEWD INTO THE AREA LATER SUN NGT...BRINGING AN INCRS IN CLOUDS. WL
KEEP THE FCST DRY ATTM AND MONITOR MODEL TRENDS IN THE COMING DAYS
FOR THE POSSIBLE INCLUSION OF SMALL RAIN CHCS.
LONG TERM...MONDAY THROUGH THURSDAY
THE EXTENDED FORECAST STARTS WITH A LARGE SURFACE HIGH PRESSURE
SYSTEM OVER THE CENTRAL U.S...WHILE A LARGE AND BROAD UPPER TROUGH
OVER THE NE TO SE U.S. WEATHER WILL BE DRY WITH JUST A BIT COOLER
TEMPS TO START. MONDAY THE SURFACE HIGH PRESSURE CENTERS OVER THE
SOUTHEASTERN PLAINS...AS THE LARGE UPPER TROUGH OVER THE EAST COAST
MOVES A BIT MORE EAST. THIS WILL BRING DRY WEATHER AND TEMPS CLOSER
TO NORMAL VALUES. ON TUESDAY CONTINUED DRY WITH WARMING TEMPS AS THE
SURFACE HIGH PRESSURE HAS MOVED OFF TO THE EAST OF AR. ON WEDNESDAY
MODELS ARE DEPICTING AN UPPER SYSTEM OVER THE SOUTHERN PLAINS...AND
WITH RETURN FLOW TO THE AREA...SOME CONVECTION SHOULD BE SEEN MAINLY
OVER TEXAS. THE FORECAST WILL REMAIN DRY OVER AR WITH WARMER TEMPS.
LATER WEDNESDAY NIGHT AND THURSDAY...A SLIGHT CHANCE OF CONVECTION
IS BACK IN THE FORECAST AS THIS UPPER SYSTEM SLOWLY MOVES EAST AND
AFFECTS AR. TEMPS WILL REMAIN WARM WEDNESDAY AND THURSDAY. OVERALL
CONFIDENCE IS AVERAGE WITH MODEL TRENDS BUT TIMING COULD CHANGE IN
FUTURE MODEL RUNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 61 76 54 73 / 80 40 20 10
CAMDEN AR 62 81 60 76 / 90 50 30 20
HARRISON AR 58 70 51 70 / 70 30 10 10
HOT SPRINGS AR 62 79 58 75 / 80 50 20 10
LITTLE ROCK AR 63 80 58 75 / 80 50 20 10
MONTICELLO AR 64 81 62 77 / 90 60 30 20
MOUNT IDA AR 58 77 54 75 / 80 50 20 10
MOUNTAIN HOME AR 60 72 51 72 / 70 30 10 10
NEWPORT AR 62 77 55 73 / 80 50 20 10
PINE BLUFF AR 64 80 61 75 / 80 50 30 20
RUSSELLVILLE AR 60 79 52 75 / 70 40 20 10
SEARCY AR 62 79 56 74 / 80 50 20 10
STUTTGART AR 64 79 59 73 / 80 50 20 20
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
56
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
903 PM MDT THU MAY 9 2013
UPDATE...
ISSUED AT 900 PM MDT THU MAY 9 2013
ALLOWED ALL WINTER HIGHLIGHTS TO EXPIRE AT 6 PM AS ORGANIZED
ACCUMULATING SNOWFALL HAS ENDED. AFTERNOON AND EVENING CONVECTION
IS NOW DYING DOWN WITH SOME GUSTY SURFACE WINDS BEING REPORTED
UNDER THOSE COLLAPSING CELLS. REMAINDER OF THE EVENING THEN WILL
SEE SOME SPOTTY SHOWERS AND GUSTY WINDS DECREASING IN INTENSITY
AND COVERAGE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 247 PM MDT THU MAY 9 2013
ELONGATED UPPER LOW FROM SRN CA ACROSS THE 4 CORNERS TO ERN CO WAS
GETTING STRETCHED APART THIS AFTERNOON...AS THE EASTERN PORTION
MOVES INTO THE PLAINS WHILE THE WESTERN PORTION DROPS SOUTHWARD.
CONVECTION WAS A LITTLE SLOW GETTING GOING TODAY...BUT RECENT KGJX
RADAR SHOWED ECHOES BUILDING ALONG THE TAVAPUTS/ROAN PLATEAUS TO THE
FLATTOPS...AND OVER THE CENTRAL AND SOUTHERN MTNS. INSTABILITY
LIKELY THE DRIVING FORCE THOUGH RAP MODEL INDICATED SOME 700-500 MB
LAYER CONVERGENCE SOUTH OF I-70 AND UNDER THE DEFORMATION/UPPER LOW
AXIS ALOFT. ISOLATED THUNDERSTORMS WILL BE POSSIBLE WITH GUSTY WINDS
AND PERHAPS SOME GRAUPEL. WILL KEEP THE CURRENT WINTER HIGHLIGHTS
GOING THOUGH PRECIPITATION LIKELY TO BE QUITE VARIABLE GIVEN THE
CONVECTIVE NATURE OF THE SHOWERS.
THE DEFORMATION ZONE SINKS SOUTH OF OUR AREA THIS EVENING AND
TONIGHT. WITH ITS EXIT AND THE LOSS OF DAYTIME HEATING...EXPECT
SHOWERS TO DIMINISH BY LATE EVENING.
A SHORTWAVE DISTURBANCE DROPPING DOWN ACROSS WRN MT THIS AFTERNOON
WILL REACH OUR FORECAST AREA BY FRI MORNING. NE UT/NW CO SHOULD SEE
CLOUDS BACK ON THE INCREASE BY SUNRISE. WEAK MOISTURE TRANSPORT IN
THE NORTHERN FLOW ALONG THIS PASSING WEAK DISTURBANCE AND DAYTIME
INSTABILITY SHOULD TRIGGER A ROUND OF AFTERNOON SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS FRIDAY AFTERNOON...MAINLY OVER THE HIGHER
TERRAIN. SNOW WILL GENERALLY BE CONFINED TO ABOVE 9500-10K FT. HIGH
TEMPS FRIDAY WILL BE WARMER THAN TODAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 247 PM MDT THU MAY 9 2013
A HIGHLY AMPLIFIED PATTERN THROUGH THE WEEKEND FLATTENS EARLY NEXT
WEEK. THERE IS HIGH FORECAST CONFIDENCE THROUGH MONDAY...THEN MODELS
SHOW INCREASING SPREAD IN FORECAST DETAILS.
A POSITIVELY TILTED RIDGE AXIS AMPLIFIES FROM THE EASTERN PACIFIC
INTO THE NORTHERN ROCKIES. THEN SLOWLY PROGRESSES UNTIL IT IS
OVERHEAD ON MONDAY. A PORTION OF THE LOW PRESSURE SYSTEM THAT
BROUGHT SHOWERS ON WEDNESDAY INTO THURSDAY IS CUTOFF IN SONORA
MEXICO. NEAR NORMAL TEMPERATURES ON SATURDAY WILL RISE WELL ABOVE
NORMAL BY MONDAY. THE WARMING AFTERNOON TEMPERATURES AND MARGINAL
MOISTURE LOOK TO OVERCOME SUBSIDENCE ON SATURDAY FOR SCATTERED
MAINLY MOUNTAIN THUNDERSTORMS. INCREASING SUBSIDENCE ON SUNDAY AND
MONDAY WITH MOISTURE DIMINISHING DUE TO CONVECTIVE VENTILATION
DIMINISH THE CHANCES OF MOUNTAIN SHOWERS. MONDAY AFTERNOON
TEMPERATURES WILL RISE ABOUT 10 DEGREES ABOVE NORMAL.
ON MONDAY A TROUGH WORKS INTO BC-WASHINGTON AND LIFTS THROUGH THE
NORTHERN ROCKIES ON TUESDAY. THIS BREAKS DOWN THE LOCAL RIDGE AND
ALSO ENTRAINS THE SONORA LOW...BOTH OF WHICH MAY INCREASE DIURNAL
THUNDERSTORM COVERAGE FOR TUESDAY INTO WEDNESDAY. BY THURSDAY BOTH
THE EC AND GFS ARE DIGGING A SHALLOW TROUGH ALONG THE WEST COAST
THAT MAY THREATEN INCREASED SHOWERS TOWARDS THE NEXT WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 247 PM MDT THU MAY 9 2013
SCATTERED TO NUMEROUS RAIN/SNOW SHOWERS OVER THE WRN CO AND SE UT
MTNS THIS AFTERNOON WILL DIMINISH THIS EVENING. ISOLATED
THUNDERSTORMS ARE POSSIBLE. STORM MOTION WILL BE TO THE WEST
SOUTHWEST AND POSSIBLY AFFECT THE WEST CENTRAL CO TAF SITES PRIOR TO
03Z. IN GENERAL...THOUGH...VFR CONDITIONS SHOULD BE PRESENT THROUGH
18Z FRI. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
OVER THE HIGHER TERRAIN AGAIN FRI AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...TGR
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
816 PM MDT THU MAY 9 2013
.UPDATE...
&&
.SHORT TERM...SHOWER ACTIVITY HAS BEEN DECREASING EARLY THIS OVER
NRN CO HOWEVER THERE IS QUITE A BIT OF ACTIVITY MOVING SOUTH INTO
SERN WY AND WRN NE. LATEST RAP DOES NOT SHOW MUCH OF THIS ACTIVITY
AFFECTING NRN CO OVERNIGHT HOWEVER UNLESS THESE SHOWERS START
DECREASING SOON SOME OF THEM WILL AFFECT THE AREA OVERNIGHT SO
WILL LEAVE IN POPS.
.AVIATION...STILL COULD SEE AN ISOLATED SHOWER OVERNIGHT SO WILL
LEAVE IN VCNTY. OTHERWISE WINDS HAVE ALREADY BECOME DRAINAGE SO
WILL KEEP THEM THAT WAY OVERNIGHT.
&&
.HYDROLOGY...NO ISSUES OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 333 PM MDT THU MAY 9 2013/
SHORT TERM...UPPER LOW STILL HOVERING AROUND FOUR CORNERS REGION
WITH ELONGATED UPPER TROUGH ACROSS COLORADO. LATEST PLATTEVILLE
PROFILER SHOWING FAIRLY DEEP NORTHEAST WINDS ACROSS CWA. AIRMASS
UNSTABLE WITH SHOWERS ACROSS MUCH OF THE AREA MOVING SOUTHWEST
ALONG WITH SOME THUNDERSTORMS. SMALL HAIL BEING REPORTED WITH THE
STORMS. SHOWERS ACROSS PLAINS HAVE BEEN PRODUCING LIGHT TO
MODERATE RAINFALL AND HAVE BEEN MOVING FAIRLY QUICKLY...ABOUT 15
MPH. FLOODING NOT MUCH OF A CONCERN DUE TO THE MOVEMENT. ACROSS
THE MOUNTAINS AND HIGHER FOOTHILLS...AREAS OF SNOW SHOWERS STILL
ONGOING. CURRENTLY THE HEAVIEST SNOW OCCURRING WITH A FEW
CONVECTIVE CELLS OVER BOULDER AND PARK COUNTIES. ACROSS ZONE 34
AND THE REST OF ZONE 37...SNOW HAD DECREASED CONSIDERABLY. EXCEPT
FOR THE POSSIBILITY OF A FEW CONVECTIVE SNOW SHOWERS PRODUCING
BRIEF MODERATE SNOWFALL THIS AFTERNOON...NOT EXPECTING SNOW TO
BECOME WIDESPREAD ACROSS ZONES 34 AND 37. WILL CANCEL THE ADVISORY
WITH THIS AFTERNOON PACKAGE. UPPER LOW PROGGED TO WEAKEN THIS
EVENING THEN REDEVELOP OVERNIGHT OVER WESTERN ARIZONA. NORTHEAST
FLOW ALOFT TO WEAKEN AND BECOME MORE NORTHERLY AS TROUGH BEGINS TO
SLIDE SOUTH ALLOWING FOR DRIER AIR TO MOVE ACROSS THE REGION.
SHOWERS TO DECREASE DURING THE EVENING AS AIRMASS STABILIZES AND
MID LEVEL ASCENT WEAKENS...SHOULD BE ENDING AROUND MIDNIGHT WITH
CLEARING SKIES. BOUNDARY LAYER WIND AND HUMIDITY PROGS SUGGEST THE
POTENTIAL FOR LOW CLOUDS AND/OR FOG ACROSS LINCOLN AND SOUTHERN
WASHINGTON COUNTY OVERNIGHT. WILL INCLUDE PATCHY FOG THERE. DON`T
THINK THE FOG WILL DEVELOP FURTHER WEST DUE TO DRAINAGE FLOW.
OVERNIGHT TEMPERATURES TO BE FAIRLY COOL...WITH MINIMUM VALUES
AROUND 40 DEGREES MOST AREAS ACROSS PLAINS. ON FRIDAY...UPPER
TROUGH WILL CONTINUE TO SLIDE SOUTH AS UPPER RIDGE BUILDS INTO THE
PACIFIC NORTHWEST. FLOW ALOFT TO REMAIN NORTHERLY THROUGH THE DAY.
AIRMASS SLIGHTLY DRIER AND MODERATES A BIT...BUT BECOMES UNSTABLE
DURING THE AFTERNOON WITH DAYTIME HEATING. ENOUGH MOISTURE FOR
SCATTERED AFTERNOON SHOWERS ALONG WITH A FEW THUNDERSTORMS...
ESPECIALLY ALONG FOOTHILLS AND EAST SLOPES OF MOUNTAINS. RAINFALL
SHOULD BE LIGHT OR BRIEFLY MODERATE...NO FLOODING ISSUES
ANTICIPATED. SNOW LEVEL AROUND 10000 FEET...COULD BE A COUPLE
INCHES OF SNOW ACCUMULATION OVER THE HIGHER RIDGES. TEMPERATURES
TO BE SLIGHTLY WARMER...WITH HIGHS IN THE 60S ACROSS THE PLAINS.
LONG TERM...MODELS SHOW A STRONG UPPER LOW TO MOVE SOUTH INTO
THE NORTHERN GREAT LAKES FRIDAY NIGHT INTO SATURDAY NIGHT. THE CWA
IS ON THE BACK SIDE AND THIS FEATURE KEEPS THE UPPER RIDGE WEST
AND SOUTHWEST OF US AT BAY SOMEWHAT...AT LEAST UNTIL SUNDAY.
MODELS HAVE WEAK NORTH-NORTHEASTERLY FLOW ALOFT FOR THE CWA FRIDAY
NIGHT...THEN NORTH-NORTHWESTERLY SATURDAY AND SATURDAY EVENING.
THEN IT IS NORTHEASTERLY THE REST OF SATURDAY NIGHT THROUGH
SUNDAY NIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW VERY WEAK
SYNOPTIC SCALE ENERGY THROUGH THE PERIOD. THERE IS WEAK UPWARD
MOTION SATURDAY AND SATURDAY EVENING. THE LOW LEVEL WIND AND
PRESSURE FIELDS STILL SHOW A SURGE OF A BIT COOLER AIR AND UPSLOPE
WINDS TO MOVE INTO THE PLAINS FRIDAY NIGHT INTO SATURDAY MORNING.
THE COLD AIR PUSH IS NOT VERY SIGNIFICANT. NORMAL DIURNAL WIND
PATTERNS LOOK REASONABLE FOR THE REST OF SATURDAY THROUGH SUNDAY
NIGHT. FOR MOISTURE...THERE IS QUITE A BIT PROGGED FRIDAY NIGHT
..WITH THE NAM SHOWING MORE SATURDAY THAN THE GFS. IN FACT...THE
NAM IS PRETTY MOIST SATURDAY NIGHT AND SUNDAY TOO. THE GFS IS
DRIEST SATURDAY...THEN SHOWS FAIRLY DECENT MOISTURE SATURDAY
NIGHT AND SUNDAY. SUNDAY NIGHT DRIES OUT SOMEWHAT. THERE IS
MINIMAL CAPE PROGGED OVER THE CWA FRIDAY EVENING...MORE ON
SATURDAY LATE DAY...ESPECAILLY ON THE NAM AND OVER THE FOOTHILLS.
SUNDAY LOOKS SIMILAR TO SATURDAY BUT ALMOST NOTHING ON THE PLAINS.
THE QPF FIELDS SHOW A TAD OF MEASURABLE PRECIPITATION MAINLY OVER
THE HIGH COUNTY FRIDAY EVENING. LATE DAY SATURDAY HAS SOME OVER
THE MOUNTAINS AND FOOTHILLS...WITH A MERE TAD OVER THE WESTERN
HALF OF THE PLAINS. THERE ARE MINOR AMOUNTS INDICATED LATE DAY
SUNDAY...ONLY IN THE HIGH COUNTRY. FOR POPS...WILL GO WITH
"CHANCE"S MAINLY LATE IN THE DAYS FOR THE MOUNTAINS AND FOOTHILLS
AND "SLIGHT CHANCES" ELSEWHERE. FOR TEMPERATURES...SATURDAY`S
HIGHS ARE SIMILAR TO FRIDAY`S. SUNDAY`S HIGHS ARE UP 2-4 C FROM
SATURDAY`S. FOR THE LATER DAYS...MONDAY THROUGH THURSDAY...UPPER
RIDGING DOMINATES MONDAY AND TUESDAY. ON WEDNESDAY AND THURSDAY
THE UPPER RIDGE FLATTENS SOMEWHAT WITH MAYBE WEAK UPPER TROUGHING.
NOTHING TO EXCITING.
AVIATION...SHOWERS ALONG WITH A FEW THUNDERSTORMS CURRENTLY
MOVING ACROSS THE DENVER AREA. THREAT TO PERSIST UNTIL AROUND 00Z.
VFR TO PREVAIL WITH CEILINGS AROUND 5000 FEET AGL THROUGH 00Z WITH
A SLIGHT CHANCE OF MVFR CEILINGS WITH PASSING SHOWERS AND STORMS.
NORTHEAST WINDS TO PREVAIL...THOUGH OUTFLOW WINDS FROM THE SHOWERS
TO CREATE ERRATIC DIRECTION WITH SOME GUSTS TO 25 KTS. AFTER
00Z...CONDITIONS TO IMPROVE WITH PERHAPS SOME LINGERING LIGHT
SHOWERS SOUTH AND WEST OF DENVER. WINDS TO BECOME SOUTHEAST DURING
THE EVENING THEN SOUTHERLY AROUND MIDNIGHT AS DRAINAGE PATTERN
DEVELOPS. ANY FOG THAT DEVELOPS SHOULD REMAIN EAST OF DENVER.
WINDS TO BECOME NORTHWEST AROUND 15Z THEN NORTHEAST AFTER 18Z WITH
SPEEDS AROUND 8 KTS. SCATTERED SHOWERS WILL DEVELOP ACROSS THE
AREA DURING THE AFTERNOON ALONG WITH A FEW THUNDERSTORMS. VFR
CONDITIONS TO PREVAIL...THOUGH CEILINGS AROUND 6000 FEET AGL
COULD DEVELOP WITH THE PASSING SHOWERS.
HYDROLOGY...SHOWERS ALONG WITH ISOLATED THUNDERSTORMS ACROSS MUCH
OF THE AREA. RAINFALL RATES WERE GENERALLY AROUND THREE TENTHS OF
AN INCH PER HOUR. THE ACTIVITY HAS BEEN MOVING FAIRLY QUICKLY SO
FLASH FLOODING HAS NOT BEEN A CONCERN. THE ACTIVITY WILL BE
DECREASING DURING THE EVENING AND SHOULD END BY MIDNIGHT. ANY
ADDITIONAL RAINFALL SHOULD BE LIGHT OR BRIEFLY MODERATE...SHOULD
NOT POSE ANY FLOODING PROBLEMS. ON FRIDAY...SCATTERED SHOWERS
ALONG WITH A FEW THUNDERSTORMS ARE EXPECTED TO AGAIN DEVELOP
DURING THE AFTERNOON. THE RAINFALL SHOULD BE LIGHT. NO FLOODING
ISSUES EXPECTED.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1057 AM MDT WED MAY 8 2013
.UPDATE...
&&
.SHORT TERM...WATER VAPOR LOOPS SHOW UPPER LOW OVER SOUTHERN UTAH
AND NORTHERN ARIZONA WITH EASTERLY WINDS ACROSS MUCH OF COLORADO.
MOISTURE CONTINUES TO STREAM NORTHWARD ACROSS CWA. SHOWERS HAVE
ALREADY DEVELOPED ACROSS PORTIONS OF THE CWA IN THE MOIST EASTERLY
FLOW. ALSO SOME THUNDERSTORMS ACROSS SOUTHERN SECTIONS OF THE
DENVER AREA AND OVER THE PALMER DIVIDE. CURRENTLY THE BULK OF THE
PRECIPITATION IS FALLING ACROSS THE MOUNTAINS AND FOOTHILLS SOUTH
OF INTERSTATE 70...WITH SCATTERED SHOWERS OVER THE URBAN CORRIDOR.
WEB CAMS ACROSS MOUNTAINS AND FOOTHILLS INDICATING SOME RAIN MIXED
WITH THE SNOW...APPEARS THE SNOW LEVEL IS AROUND 8500 FEET. NEXT
BATCH OF PRECIPITATION MOVING NORTH ACROSS EL PASO COUNTY...SHOULD
BE MOVING ACROSS THE PALMER DIVIDE SHORTLY. OVERALL CURRENT
FORECASTS SEEM IN ORDER FOR THIS AFTERNOON AND EVENING...ALREADY
MADE ADJUSTMENTS EARLIER TO INCLUDE THUNDER. STILL SOME CONCERN
FOR FLASH FLOOD POTENTIAL ALONG FOOTHILLS DUE TO THE WEAK STORM
MOTION THOUGH OVERALL THREAT STILL SEEMS TOO LOW FOR A FLASH FLOOD
WATCH. WILL CONTINUE TO MONITOR. SOME OF THE STORMS COULD PRODUCE
SMALL HAIL AS RAP STILL SHOWING CAPES FROM 500-1000 J/KG INTO THE
EVENING...NOT EXPECTING SEVERE STORMS AT THIS POINT. LASTLY...WILL
CONTINUE WITH THE ADVISORY FOR ZONE 34. STILL LOOKING AT SOME
POTENTIAL FOR HEAVY SNOW ABOVE 10000 FEET...MAINLY DUE TO THE
CONVECTION RATHER THAN OROGRAPHICS. WILL CONTINUE TO MONITOR TO
SEE WHAT DEVELOPS FOR THE OVERNIGHT. WILL ALSO KEEP AN EYE ON ZONE
37 FOR THIS EVENING AS THERE IS SOME POTENTIAL FOR SOUTHEAST WINDS
WHICH COULD BRING MORE LOW LEVEL MOISTURE INTO SOUTH PARK.
.AVIATION...FIRST BATCH OF SHOWERS DEVELOPED ACROSS THE AREA
AIRPORTS WITH SOME THUNDER REPORTED AT KAPA. A FEW SHOWERS STILL
IN THE VICINITY. CEILINGS HAVE IMPROVED AFTER THE SHOWERS MOVED
THROUGH. NEXT BATCH OF SHOWERS MOVING NORTH INTO DOUGLAS AND
ELBERT COUNTIES...WILL BE MOVING INTO THE DENVER AREA IN THE NEXT
TWO HOURS. SOME EMBEDDED THUNDERSTORMS WITH THE BATCH OF SHOWERS.
ILS CONDITIONS PROBABLE WITH THE SHOWERS ALONG WITH POSSIBLE MVFR
CEILINGS. OVERALL CURRENT TAF TRENDS SEEM ON TRACK...WILL MAKE
SOME ADJUSTMENTS TO TIMING THE ONSET OF PRECIPITATION. WINDS TO
SHIFT TO THE NORTHEAST DURING THE AFTERNOON...BUT WILL BE
ERRATIC AND GUSTY NEAR THE SHOWERS AND STORMS WITH POSSIBLE GUSTS
TO 25 OR 30 KTS.
&&
.HYDROLOGY...RAIN SHOWERS ALONG WITH EMBEDDED THUNDERSTORMS
EXPECTED THIS AFTERNOON. SOME CONCERN STILL EXISTS FOR THE
POTENTIAL FOR HEAVY RAIN DUE TO SLOW STORM MOTIONS. THREAT LOOKS
LOCALIZED...BUT BURN AREAS WILL NEED TO BE MONITORED. STRONGER
STORMS MAY PRODUCE UP TO AN INCH IN AN HOUR.
&&
.PREV DISCUSSION... /ISSUED 335 AM MDT WED MAY 8 2013/
SHORT TERM...WATER VAPOR IMAGERY SHOWING THE BROAD UPPER LOW
MOVING SLOWLY EAST ACROSS THE SOUTHERN UTAH AND NORTHERN ARIZONA
BORDER EARLY THIS AM. MODELS ARE FAIRLY CONSISTENT ON TRACKING THE
LOW TO THE 4 CORNERS REGION BY THIS AFTERNOON THEN THE LOW SLOWLY
WEAKENS AND REMAINS RATHER STATIONARY TONIGHT. QG FIELDS SHOWING
INCREASING ASCENT AT ALL LEVELS OVER NORTHERN COLORADO THIS
AFTERNOON WHILE WEAK...YET DEEPENING UPSLOPE FLOW BECOMES
ESTABLISHED LATER TODAY AND TONIGHT OVER THE FRONT RANGE.
CURRENTLY...MOST OF THE CWA IS PRECIP FREE BUT WEATHER WILL BE
CHANGING TOWARDS MID MORNING AND AFTERNOON. RADAR AND
OBSERVATIONS SHOWING PRECIP INCREASING OVER SOUTHERN AND SOUTHWEST
COLORADO WITH SOME LIGHTNING OVER SOUTHWEST CO. THERE IS THUNDER
POTENTIAL OVER ALL CWA TODAY AND EVEN NAM/RUC SHOWING SFC BASED
CAPES FROM 500-1000J/KG BY AFTERNOON GIVEN LOWER 60S TEMPERATURES
AND LOWER 40S DEWPOINTS. THE OVERALL SEVERE POTENTIAL IS LOW BUT
GIVEN CAPES AND LOW FREEZING LEVELS...CERTAINLY SMALL HAIL
POSSIBLE ALONG WITH HEAVY RAIN. A BIT CONCERNED ABOUT FIRE BURN
SCARS WITH FLASH FLOOD POTENTIAL GIVEN WEAK STORM MOTIONS AND
POTENTIAL FOR ECHO TRAINING. STILL OVERALL THREAT SEEMS TOO LOW TO
ISSUE A FLASH FLOOD WATCH AT THIS TIME. CERTAINLY THESE AREAS WILL
NEED TO BE WATCHED CLOSELY AS LAST EVENING STORMS WERE DUMPING
QUITE A BIT OF RAIN IN ISOLATED SPOTS. WILL HAVE LIKELY POPS IN
MOST LOCALES FOR THIS AFTERNOON AND INTO TONIGHT.
AS FOR THE MOUNTAINS...THERE IS SOME SNOW POTENTIAL ESPECIALLY
OVER ZONE 34. FORECAST FREEZING LEVELS WILL KEEP SNOW ABOVE 9000
FEET WITH ANY HEAVY SNOW MAINLY ABOVE 10000 FEET. HAVE DECIDED TO
ISSUE A ADVISORY FOR NOW BUT CERTAINLY POTENTIAL FOR HEAVIER
SNOWFALL IS POSSIBE. GIVEN THE WEAKENING NATURE OF THE LOW AND
UNCERTAIN AREAL COVERAGE NOT READY TO GO WITH A WARNING. WILL
LATE THE DAY SHIFT TAKE ANOTHER LOOK ON HOW THINGS ARE EVOLVING.
LONG TERM...THE UPPER LOW OVER THE FOUR CORNERS WILL DEEPEN INTO
THE SOUTHWEST STATES TO BEGIN PULLING AWAY FROM COLORADO. SURFACE
HIGH PRESSURE PUSHING IN FROM THE NORTHERN GREAT PLAINS TO KEEP
MOISTURE FOCUSED AGAINST THE SOUTHERN FOOTHILLS AND CENTRAL
MOUNTAINS. WILL HAVE THE WINTER WEATHER ADVISORY GOING THROUGH THE
AFTERNOON AS SNOW LEVELS WILL BEGIN AROUND 8500-9000 FT THURSDAY
MORNING THEN SLOWLY RAISE TO AROUND 10000 IN THE AFTERNOON AS THE
SNOW AND RAIN IS DIMINISHING. EXPECT ANOTHER 2-4 INCHES AT
ELEVATIONS ABOVE 9500 THURSDAY OVER THE MOUNTAINS OF PARK...SUMMIT
AND CLEAR CREEK COUNTIES. RAIN WILL BE CONTINUING AT LOWER
ELEVATIONS THURSDAY WITH A FEW ISOLATED TSTORMS POSSIBLE.
TEMPERATURES THURSDAY WILL LIKELY STAY IN THE 50S OVER THE PLAINS
WITH SLIGHTLY WARMER WEATHER OUT ON THE FAR NORTHEASTERN PLAINS
FURTHER AWAY FROM THE UPSLOPE EFFECTS. MOUNTAINS WILL REACH INTO
THE 40S WITH NORTH AND MIDDLE PARKS REACHING THE 50S. THURSDAY
NIGHT ALL THE PRECIPITATION WILL BE DIMINISHING NORTH TO SOUTH
WITH CLEARING SKIES AND DIMINISHING WINDS.
FRIDAY AND SATURDAY WILL FEATURE SHOWERS EACH DAY AND A SLIGHT
CHANCE OF A THUNDERSTORM OR TWO. FRIDAY WILL WARM AROUND 5-8
DEGREES...THEN A COOL PUSH ARRIVES FOR SATURDAY TO COOL TEMPS BACK
DOWN A FEW DEGREES. THE PUSH WILL ENHANCE SHOWER ACTIVITY YET
AGAIN AGAINST THE FOOTHILLS...PUT MOISTURE IS EXPECTED TO BE LESS
WITH THIS SYSTEM.
SUNDAY AND INTO THE FIRST HALF OF NEXT WEEK WILL FEATURE A WARMING
AND DRYING TREND AS MODERATE TO STRONG UPPER RIDGING MOVES IN
FROM THE WEST. TEMPERATURES WILL LIKELY REACH AND GO ABOVE NORMAL
READINGS...WITH THE PLAINS HAVING READINGS IN THE 70S AND LOW 80S
WHILE THE MOUNTAINS ENJOY READINGS IN THE 50S TO 60S.
AVIATION...CLOUDS WILL INCREASE AND CEILINGS LOWERING DURING THE
MORNING HOURS WITH ILS CONDITIONS PROBABLE BY LATE AM OR EARLY
AFTERNOON. ENOUGH INSTABILITY FOR EMBEDDED THUNDERSTORMS THIS
AFTERNOON AND EVENING AS WELL. CURRENT LOCAL TERMINALS LOOK
REASONABLE AND EXPECT ONLY SOME MINOR TWEAKS WITH TIMING AND
CEILING HEIGHTS. SURFACE WINDS WILL BE SHIFTING NORTHEAST BY
AFTERNOON. THERE WILL BE SOME ERRATIC AND GUSTY WINDS WITH
SHOWERS AND STORMS SO SPEEDS COULD JUMP TO 25KT IN THE STRONGER
STORMS.
HYDROLOGY...RAIN SHOWERS AND EMBEDDED THUNDERSTORMS WILL BE ON
THE INCREASE BY AFTERNOON WITH SOME CONCERN FOR POTENTIAL FOR
HEAVY RAIN GIVEN INCREASING MOISTURE LEVELS AND SLOW STORM
MOTIONS. OVERALL THREAT SEEMS MORE LOCALIZED BUT BURN AREAS WILL
NEED TO BE WATCHED CLOSELY. BASED ON LAST NIGHT`S ACTIVITY COULD
SEE A AN INCH OF RAIN IN LESS THAN AN HOUR WITH THE STRONGER
STORMS TODAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THURSDAY FOR COZ034.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1131 PM MDT TUE MAY 7 2013
.UPDATE...
ISSUED AT 925 PM MDT TUE MAY 7 2013
UPDATED FOR CURRENT OBSERVATIONS AND RADAR TRENDS. HAVE KEPT
CURRENT WINTER STORM WATCH FOR THE HIGH MT PEAKS...AOA 10K FEET
AS QUICK PEAK AT 00Z NAM NOT AS BULLISH WITH QPF ACROSS THE
REGION. STILL LOOKS LIKE BEST SNOW ACCUMS WILL BE ACROSS THE
CENTRAL MTS AND POSSIBLY PIKES PEAK WITH ADVISORY AMOUNTS
LIKELY...THOUGH WILL LET MID SHIFT GET A LOOK AT LATEST GLOBAL
MODELS BEFORE ISSUING ANY HIGHLIGHTS.
LATEST NAM PICKING UP ON THE HRRR AND RAP TRENDS OF SHOWERS
DEVELOPING ACROSS THE SOUTHERN MTS AFTER MIDNIGHT AND SPREADING
NORTH AND EAST THROUGH THE EARLY MORNING HOURS AS JETLET MOVES
ACROSS THE SOUTHERN ROCKIES AND MID LEVEL DEFORMATION INCREASES
ACROSS THE AREA. LATEST NAM QPF TREND ALSO BODES WELL FOR THE
WALDO CANYON BURN SCAR...AND WILL WAIT AND SEE IF THE GLOBAL
MODELS FOLLOW SUIT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 243 PM MDT TUE MAY 7 2013
ACTIVE METEOROLOGICAL REGIME DURING THE SHORT TERM(ESPECIALLY
WEDNESDAY) WITH ONE CONCERN BEING HEAVY RAIN POTENTIAL(SHOWERS AND
THUNDERSTORMS)...ESPECIALLY OVER THE WALDO CANYON BURN SCAR BUT ALSO
OVER MANY OTHER LOCATIONS OF THE FORECAST DISTRICT AS VIGOROUS
CLOSED UPPER LOW SHIFTS FROM FAR NORTHWESTERN ARIZONA AT 00Z
WEDNESDAY INTO SOUTHWESTERN COLORADO BY 00Z THURSDAY. I WILL BE
ISSUING A FLOOD WATCH FOR THE FLASH FLOODING POTENTIAL(FOCUSED ON
THE WALDO CANYON BURN SCAR AREA) FOR PUBLIC ZONES 81/84 AND 85 FROM
12Z WEDNESDAY THROUGH 00Z FRIDAY.
ANOTHER CONCERN WILL BE THE STRONG TO SEVERE THUNDERSTORM POTENTIAL
OVER PORTIONS OF THE SOUTHEASTERN COLORADO PLAINS FROM WEDNESDAY
INTO WEDNESDAY NIGHT THANKS TO DEEPENING ATMOSPHERIC MOISTURE
LEVELS...UPPER ENERGY MOVING ACROSS THE CWFA...0 TO 6 KM BULK SHEAR
VALUES AROUND 40 KNOTS...LOCALIZED CAPES AROUND 1800 J/KG AND
LOCALIZED LIS AROUND -6C. SPC 2ND DAY CONVECTIVE OUTLOOK HAS
PORTIONS OF KIOWA...BENT...PROWERS AND BACA COUNTY IN THEIR SEVERE
THUNDERSTORM OUTLOOK FOR WEDNESDAY. I WILL HAVE SEVERE THUNDERSTORM
WORDING IN MY IMPENDING ZONES/GRIDS FOR THE ABOVE MENTIONED COUNTIES
FOR WEDNESDAY AFTERNOON.
AN ADDITIONAL METEOROLOGICAL ISSUE WILL BE THE POTENTIAL FOR HIGHER
TERRAIN ACCUMULATING SNOW...ESPECIALLY FROM WEDNESDAY INTO
THURSDAY. I WILL BE ISSUING A WINTER STORM WATCH FOR PUBLIC ZONES
58/60/73/75/80 AND 82 FROM 13Z WEDNESDAY TO 03Z FRIDAY TO ACCOUNT
FOR THIS POTENTIAL. IN ADDITION..FOR TONIGHT I HAVE DEPICTED
GENERALLY UNDER 4 INCHES OF SNOW OVER PORTIONS OF ZONES 58 AND 60
WILL LOWER SNOW AMOUNTS OVER OTHER HIGHER TERRAIN LOCATIONS.
MINIMUM TEMPERATURES TONIGHT ARE EXPECTED TO RUN A CATEGORY OR SO
ABOVE EARLY MAY CLIMATOLOGICAL AVERAGES MOST AREAS WHILE MAXIMUM
TEMPERATURES ON WEDNESDAY SHOULD RUN A CATEGORY OR TWO BELOW EARLY
MAY CLIMATOLOGICAL AVERAGES. FINALLY...LOW-GRADE GRADIENT WINDS ARE
ANTICIPATED THROUGH 00Z THURSDAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 243 PM MDT TUE MAY 7 2013
...MORE HEAVY RAIN IN THE FORECAST...
...HEAVY WET SNOW FOR THE HIGHER ELEVATIONS...
EXTENDED PERIOD CONTINUES TO LOOK FAIRLY WET...PARTICULARLY WED EVE THROUGH
THU EVE...AND THEN ANOTHER ROUND LATE FRI INTO THE WEEKEND. MAIN CONCERN
CONTINUES TO BE THE WALDO BURN SCAR DURING THIS TIME.
WED EVE INTO THU...UPPER LOW OVER S CENTRAL CO WILL RETROGRADE WWD TO
AZ BY THU EVE. HIGH PWATS CIRCULATING AROUND THE LOW WILL KEEP THE
THREAT OF HEAVY SHOWER ACTIVITY GOING OVER MUCH OF OUR CWA. THE HIGHEST
QPF STILL LOOKS TO BE OVER THE CONTDVD N OF KMYP...AND THE PIKES
PEAK REGION. TOTAL QPF FOR THE WALDO AREA IS IN EXCESS OF ONE
INCH...SO THE BURN SCAR WILL REMAIN UNDER THE GUN THROUGH THU...
DURING THE TIME OF OUR FLASH FLOOD WATCH. MUCH OF THE ERN PLAINS
WILL BE SOCKED IN WITH CLOUDS AND PRECIP AS UPSLOPE FLOW PERSISTS.
THIS WILL LIMIT CONVECTIVE POTENTIAL OVER THE PLAINS AND COULD MEAN
MORE OF A STRATIFORM EVENT...HOWEVER ISOLD TS WILL REMAIN A THREAT
PARTICULARLY ALONG AND NR THE MTS. THERE WILL ALSO BE A LOW RISK OF
SOME STRONG OR SVR CONVECTION OVER THE ERN PLAINS EARLY WED EVE.
MOST OF THE HEAVIER CONVECTION SHOULD BE E OF OUR AREA AFTER 00Z
WED...BUT ONE OR TWO STRONG STORMS COULD BE ONGOING OVER KIOWA
COUNTY EARLY IN THE PERIOD.
HAVE GONE ON THE LOW SIDE OF GUIDANCE FOR TEMPS ON THU...MAINLY
UPPER 50S FOR THE PLAINS. H7 TEMPS WILL BE NR ZERO...AND WITH CLOUD
COVER AND PRECIP DO NOT ANTICIPATE A LOT OF MIXING. SNOW LEVELS WILL
REMAIN AROUND 9K FEET THROUGH THU FOR THE NRN RANGES...AND 10K FEET
OR HIGHER FOR THE SW MTS. SO...EXPECT THE HEAVIER SNOW TOTALS TO BE
ABOVE 11000 FEET...WITH SOME HEAVY WET SNOW FOR THE PASSES. HIGHEST
ELEVATIONS SUCH AS PIKES PEAK AND THE HIGHER PEAKS IN THE SAWATCH
AND SANGRES COULD SEE 1-2 FEET OF SNOW BY LATE THU. SNOW LEVELS
COULD BRIEFLY DROP AS LOW AS 8 K FEET OR POSSIBLY LOWER IN HEAVIER
SHOWERS.
A BIT OF A RESPITE THU NIGHT INTO FRI MORNING BEFORE PRECIP CHANCES
PICK UP AGAIN LATE FRI...AS A COLD FRONT RACES SWD THROUGH ERN CO.
THIS WILL BRING ANOTHER PERIOD OF UPSLOPE TO THE PLAINS ON SAT.
THE 12Z GFS ALSO SHOWS AN INFLUX OF DEEP MOISTURE INTO THE CENTRAL
ROCKIES...ASSOCIATED WITH A SUBTROPICAL PLUME THAT WILL SLOWLY
MOVE TO THE SE THROUGH EARLY NEXT WEEK. THIS MAY ACTUALLY END UP
BEING AN EVEN GREATER THREAT FOR FLASH FLOODING...WITH THE POTENTIAL
FOR STRONGER CONVECTION ALONG WITH THE HIGH PWATS. ENSEMBLE GRIDS
REFLECT HIGH POPS THROUGH THIS PERIOD...AND SEE NO REASON TO CHANGE
THEM AT THIS POINT. FOR THE WEEKEND...TEMPS WILL REMAIN BELOW
AVERAGE...IN THE 60S FOR THE PLAINS AND 50S FOR THE MTS. FLOW SHOULD
BECOME MORE W-SW FOR EARLY NEXT WEEK...WHICH WILL LEAD TO WARMER WX
FOR THE AREA. ROSE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1119 PM MDT TUE MAY 7 2013
FIRST WAVE OF -SHRA/-TSRA MOVING OFF TO THE NORTHEAST WITH NEXT
WAVE ALREADY SPARKING SOME CONVECTION OVER NORTHERN NM. FOR
KALS...A FEW -SHRA ALREADY INTO THE SRN SAN LUIS VALLEY AS OF
05Z...AND WILL LIKELY REACH THE TERMINAL 06Z-07Z. ACTIVITY LOOKS
FAIRLY LIGHT AND SCT AT THIS POINT...SO WILL RUN WITH VFR CIGS AND
ONLY A VCSH MENTION FOR NOW. EXPECT A FEW -SHRA TO LINGER OVER
THE TERMINAL THROUGH THE DAY WED...SO KEPT VCSH GOING UNTIL
EVENING...THOUGH AGAIN SHOWERS WILL BE FAIRLY LIGHT AND BRIEF. FOR
KPUB AND KCOS...VFR CIGS EXPECTED THROUGH THE NIGHT...THOUGH -SHRA
CHANCES WILL BE INCREASING 10-11Z AS PRECIP MOVES NORTH OUT OF NM.
KEPT VFR CIGS GOING THROUGH THE DAY WED WITH VCSH THE ENTIRE
PERIOD...WITH A WINDOW FOR POSSIBLE TSRA FROM 16-17Z UNTIL 22-23Z.
OVER THE MOUNTAINS...EXPECT LOWERING CIGS OVERNIGHT WITH MOUNTAIN
PEAKS OBSCURED FROM LATE TONIGHT THROUGH THE DAY WED DUE TO
INCREASING -SHRA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 6 AM MDT WEDNESDAY THROUGH THURSDAY
AFTERNOON FOR COZ081-084-085.
WINTER STORM WATCH FROM 7 AM MDT WEDNESDAY THROUGH THURSDAY
EVENING FOR COZ058-060-073-075-080-082.
&&
$$
UPDATE...MW
SHORT TERM...77
LONG TERM...ROSE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
721 AM EDT WED MAY 8 2013
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE CENTERED OVER VIRGINIA EARLY TODAY WILL
DRIFT TO THE NORTHEAST AND PASS SLOWLY OVER OUR REGION THROUGH
THURSDAY. A WARM FRONT AND NEW AREA OF LOW PRESSURE MAY ORGANIZE
NEAR THE MID ATLANTIC STATES FRIDAY NIGHT INTO SATURDAY. A COLD
FRONT IS FORECAST TO FOLLOW EARLY ON SUNDAY WITH HIGH PRESSURE
BUILDING TO OUR SOUTH ON MONDAY INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE DEEP BUT ATLANTIC MOISTURE PLUME MOVING AROUND THE SLOWLY
ADVANCING AND STACKED LOW AND SOME ELEVATED INSTABILITY WERE CAUSING
A SWATH OF RAIN WITH SOME EMBEDDED THUNDER FROM WELL OFF THE
SOUTHERN DELMARVA INTO NORTHEAST NEW JERSEY EARLY THIS MORNING.
ACTIVITY QUICKLY BECAME MORE SCATTERED AS ONE MOVED SOUTHWEST.
AS OF 09Z, THE MESOSCALE NAM AND THE HRRR HAD SHIFTED THE AXIS OF
BEST RAINFALL FURTHER NORTH, BUT UNFORTUNATELY RADAR RETURNS
SHOWED THE SWATH DEVELOPING A WESTWARD MOVEMENT. WE HAVE MENTIONED
THE POSSIBILITY OF HEAVY RAIN THIS MORNING FROM EAST CENTRAL
THROUGH NORTH CENTRAL NEW JERSEY AND INTO THE SOUTHERN POCONOS.
ALL MODELS STILL SHIFT THE RAIN NORTH WITH TIME TODAY. OUR
FORECAST STILL LIFTS THE PRECIPITATION NORTH AND OUT OF THE AREA
THIS MORNING AND THEN RE-FOCUSES ON THE LOW. SOME ENERGY IS
FORECAST TO REVOLVE AROUND THE LOW, AND IT ESPECIALLY SEEMS TO
TARGET OUR WESTERN ZONES.
WE CARRY A SLIGHT CHANCE OF THUNDER FIRST WITH THE SWATH OFF THE
OCEAN. WE THEN EXTEND THE SLIGHT CHANCE AROUND THE FORECAST AREA AS
THE LOW APPROACHES AND TEMPERATURES COOL ALOFT.
MID LEVEL CLOUDS HAD BROKEN FAR SOUTH, AND THIS HAD ALLOWED SOME FOG
TO FORM THERE. THAT IS COVERED IN THE FORECAST AND WITH A SPECIAL
WEATHER STATEMENT THAT RUNS UNTIL 1330Z.
TEMPERATURES ARE ON THE COOLER SIDE OF GUIDANCE, ALTHOUGH WE DO
START FROM A FAIRLY WARM PLACE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE MODELS SHOW DECENT AGREEMENT REGARDING MORE ENERGY ROTATING
AROUND THE LOW AND LIFTING FROM THE SOUTH INTO OUR FORECAST AREA
TONIGHT, AND WE CARRY HIGH CHANCE POPS IN RESPONSE. AGAIN, WE ARE
NOT MENTIONING ANY HEAVY RAIN. WE DO CARRY THUNDER THROUGH THE
EVENING. TEMPERATURES ARE A GUIDANCE/CONTINUITY BLEND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
UNSETTLED CONDITIONS WILL REMAIN ACROSS THE AREA FROM THURSDAY INTO
THE WEEKEND. FIRST...THE WEAKENING UPPER LOW WILL CONTINUE TO
TRANSLATE NORTHEAST ACROSS THE REGION. WHILE THE SYSTEM IS NOT VERY
STRONG...IT WILL HAVE ENOUGH ENERGY/INSTABILITY TO CREATE SOME SCT
SHOWERS INTO THE FIRST PART OF THE EXTENDED. A BRIEF BREAK BEHIND
THE LOW MAY CREATE LESSER CHC FOR PCPN FRIDAY...THEN ANOTHER SYSTEM
APPROACHED FROM THE OHIO VALLEY FRI NIGHT AND LINGERS ACROSS THE
AREA INTO SUNDAY. THE APPROACHING SYSTEM LATER FRI MAY ARRIVE EARLY
ENOUGH TO PRODUCE SOME SVR TSTMS ACROSS THE NW ZONES. THE SPC HAS
PLACED A SLGT RISK FOR SVR TSTMS THAT DAY. A COLD FRONT WILL BRING
DRIER AIR AND COOLER TEMPERATURES LATER SUNDAY. THESE COOLER
READINGS WILL LAST INTO EARLY NEXT WEEK.
EXCEPT FOR FRIDAY...TEMPERATURES WILL MOSTLY BE NORMAL OR BELOW
NORMAL ACROSS THE REGION. ON FRIDAY...DAYTIME HEATING SHOULD BOOST
READINGS WELL INTO THE 70S AND LOW 80S ACROSS THE AREA. IT WILL
REMAIN COOLER ALONG THE SHORE ON FRIDAY.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
WITH THE 12Z TAFS WE ARE STARTING THEM FAIRLY PESSIMISTICALLY WITH
IFR CONDITIONS AS LOW CLOUDS HAVE DEVELOPED AND NUMEROUS SHRAS ARE
AROUND. THUNDER PRECLUDED BECAUSE OF THEIR CURRENT LOCATIONS (NE
OF TERMINALS) AND MOTION.
THE PRESENT TAFS WILL STAY OPTIMISTIC IN LIFTING THE IFR STRATUS
EARLIER THAN WE HAD BEEN FORECASTING. ALL SITES BREAK OUT TO VFR
BY 16Z IN THE PRESENT TAFS, WITH THE SOUTHEASTERN AND DELAWARE
VALLEY SITES BREAKING OUT DURING THE DAYLIGHT MORNING HOURS. WE
WILL MONITOR.
WE HAVE CONTINUED THE OPTIMISTIC FORECAST INTO THE AFTERNOON BY
ONLY FORECASTING A PROB30 FOR TSTM ACTIVITY AT MOST SITES (NOT THE
SOUTHEASTERN ONES) AND THEN GOING VFR THROUGH 09/06Z (12Z AT
PHL). WE MAY ULTIMATELY INSERT AT LEAST SOME STRATUS INTO THE
FORECAST FOR THE PERIOD AFTER 06Z IN SUBSEQUENT ISSUANCES. WINDS
ARE NOT EXPECTED TO BE A MAIN CONCERN TODAY, BUT THEY SHOULD VEER
FROM EAST OR NORTHEAST TO SOUTHEAST DURING THE TAF PERIOD AT 10 KT
OR LESS.
OUTLOOK...
THU INTO FRI NIGHT...MOSTLY VFR. SCATTERED SHOWERS/TSTMS FRI
AFTERNOON MAY BRING LOWER CIGS/VSBYS.
SAT THRU SUN...LOWER CONDITIONS EXPECTED WITH CIGS/SHOWERS SAT AND
SAT NIGHT. IMPROVING CONDITIONS LATER SUNDAY.
&&
.MARINE...
WITH BROAD LOW PRESSURE APPROACHING OUR REGION AND A CONTINUED
ONSHORE FLOW, SEAS ARE EXPECTED TO BE ELEVATED THROUGH TONIGHT
ON OUR ATLANTIC COASTAL WATERS. A SMALL CRAFT ADVISORY FOR
HAZARDOUS SEAS CONTINUES FOR ALL OF OUR ATLANTIC COASTAL WATERS
THROUGH TONIGHT. SEAS AND WINDS ARE EXPECTED TO REMAIN BELOW SCA
LEVELS FOR DELAWARE BAY. VISIBILITIES WILL BE LOWERED AT TIMES IN
SCATTERED SHOWERS AND ISOLATED THUNDER MAINLY THIS AFTERNOON,
ALTHOUGH NORTHERN ATLANTIC WATERS WILL SEE SOME HEAVIER RAIN AND
PERHAPS SOME THUNDER EARLY THIS MORNING. ANOTHER SHOT OF SHOWER AND
THUNDERSTORM ACTIVITY IS POSSIBLE TONIGHT.
OUTLOOK...SCA CONDITIONS FOR HAZ SEAS WILL PROBABLY COME DOWN THU
MORNING AS THE LONGER PERIOD SWELLS DIMINISH. ANOTHER PERIOD OF
SCA CONDITIONS WILL DEVELOP ACROSS THE OCEAN WATERS FRI NIGHT AND
LAST INTO THE WEEKEND.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT
THURSDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...GIGI/O`HARA
NEAR TERM...DELISI
SHORT TERM...DELISI
LONG TERM...O`HARA
AVIATION...DELISI/GIGI
MARINE...DELISI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
601 AM EDT WED MAY 8 2013
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE CENTERED OVER VIRGINIA EARLY TODAY WILL
DRIFT TO THE NORTHEAST AND PASS SLOWLY OVER OUR REGION THROUGH
THURSDAY. A WARM FRONT AND NEW AREA OF LOW PRESSURE MAY ORGANIZE
NEAR THE MID ATLANTIC STATES FRIDAY NIGHT INTO SATURDAY. A COLD
FRONT IS FORECAST TO FOLLOW EARLY ON SUNDAY WITH HIGH PRESSURE
BUILDING TO OUR SOUTH ON MONDAY INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE DEEP BUT ATLANTIC MOISTURE PLUME MOVING AROUND THE SLOWLY
ADVANCING AND STACKED LOW AND SOME ELEVATED INSTABILITY WERE CAUSING
A SWATH OF RAIN WITH SOME EMBEDDED THUNDER FROM WELL OFF THE
SOUTHERN DELMARVA INTO NORTHEAST NEW JERSEY EARLY THIS MORNING.
ACTIVITY QUICKLY BECAME MORE SCATTERED AS ONE MOVED SOUTHWEST.
AS OF 09Z, THE MESOSCALE NAM AND THE HRRR HAD SHIFTED THE AXIS OF
BEST RAINFALL FURTHER NORTH, BUT UNFORTUNATELY RADAR RETURNS
SHOWED THE SWATH DEVELOPING A WESTWARD MOVEMENT. WE HAVE MENTIONED
THE POSSIBILITY OF HEAVY RAIN THIS MORNING FROM EAST CENTRAL
THROUGH NORTH CENTRAL NEW JERSEY AND INTO THE SOUTHERN POCONOS.
ALL MODELS STILL SHIFT THE RAIN NORTH WITH TIME TODAY. OUR
FORECAST STILL LIFTS THE PRECIPITATION NORTH AND OUT OF THE AREA
THIS MORNING AND THEN RE-FOCUSES ON THE LOW. SOME ENERGY IS
FORECAST TO REVOLVE AROUND THE LOW, AND IT ESPECIALLY SEEMS TO
TARGET OUR WESTERN ZONES.
WE CARRY A SLIGHT CHANCE OF THUNDER FIRST WITH THE SWATH OFF THE
OCEAN. WE THEN EXTEND THE SLIGHT CHANCE AROUND THE FORECAST AREA AS
THE LOW APPROACHES AND TEMPERATURES COOL ALOFT.
MID LEVEL CLOUDS HAD BROKEN FAR SOUTH, AND THIS HAD ALLOWED SOME FOG
TO FORM THERE. THAT IS COVERED IN THE FORECAST AND WITH A SPECIAL
WEATHER STATEMENT THAT RUNS UNTIL 1330Z.
TEMPERATURES ARE ON THE COOLER SIDE OF GUIDANCE, ALTHOUGH WE DO
START FROM A FAIRLY WARM PLACE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE MODELS SHOW DECENT AGREEMENT REGARDING MORE ENERGY ROTATING
AROUND THE LOW AND LIFTING FROM THE SOUTH INTO OUR FORECAST AREA
TONIGHT, AND WE CARRY HIGH CHANCE POPS IN RESPONSE. AGAIN, WE ARE
NOT MENTIONING ANY HEAVY RAIN. WE DO CARRY THUNDER THROUGH THE
EVENING. TEMPERATURES ARE A GUIDANCE/CONTINUITY BLEND.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
UNSETTLED CONDITIONS WILL REMAIN ACROSS THE AREA FROM THURSDAY INTO
THE WEEKEND. FIRST...THE WEAKENING UPPER LOW WILL CONTINUE TO
TRANSLATE NORTHEAST ACROSS THE REGION. WHILE THE SYSTEM IS NOT VERY
STRONG...IT WILL HAVE ENOUGH ENERGY/INSTABILITY TO CREATE SOME SCT
SHOWERS INTO THE FIRST PART OF THE EXTENDED. A BRIEF BREAK BEHIND
THE LOW MAY CREATE LESSER CHC FOR PCPN FRIDAY...THEN ANOTHER SYSTEM
APPROACHED FROM THE OHIO VALLEY FRI NIGHT AND LINGERS ACROSS THE
AREA INTO SUNDAY. THE APPROACHING SYSTEM LATER FRI MAY ARRIVE EARLY
ENOUGH TO PRODUCE SOME SVR TSTMS ACROSS THE NW ZONES. THE SPC HAS
PLACED A SLGT RISK FOR SVR TSTMS THAT DAY. A COLD FRONT WILL BRING
DRIER AIR AND COOLER TEMPERATURES LATER SUNDAY. THESE COOLER
READINGS WILL LAST INTO EARLY NEXT WEEK.
EXCEPT FOR FRIDAY...TEMPERATURES WILL MOSTLY BE NORMAL OR BELOW
NORMAL ACROSS THE REGION. ON FRIDAY...DAYTIME HEATING SHOULD BOOST
READINGS WELL INTO THE 70S AND LOW 80S ACROSS THE AREA. IT WILL
REMAIN COOLER ALONG THE SHORE ON FRIDAY.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
WIDELY SCATTERED ACTIVITY THREATENING THE TAF SITES EARLY THIS
MORNING WAS MOSTLY LIGHT. THE STEADY EAST WIND AND A SOLID DECK OF
MID LEVEL CLOUDINESS WAS KEEPING ANYTHING OTHER THAN SOME MVFR FOG
FROM FORMING, BUT STRATUS WAS DEVELOPING AROUND THE DELAWARE VALLEY
AND NORTHWESTERN SITES ON THAT EAST WIND.
THAT SAID, THERE WAS AN AREA OF DRIER AIR MOVING UP FROM
SOUTHEASTERN VA, MUCH OF THE DELMARVA AND FAR SOUTHERN NJ THAT WAS
CAUSING THE MID LEVEL CLOUDS AND STRATUS TO ERODE. THAT WAS QUICKLY
FOLLOWED BY THE DEVELOPMENT OF SOME IFR FOG OVER SOUTHERN DELAWARE
AND THE ADJACENT MARYLAND EASTERN SHORE.
ON THE ONE HAND, IT`S BY NO MEANS CERTAIN THAT THE FOG CAN ADVANCE
INTO THE TAF SITES BECAUSE WE`RE NOT SURE THAT THE DRY AIR PUSHES
FAR ENOUGH NORTH. ON THE OTHER HAND, WE`RE NOT CERTAIN THAT THE
STRATUS STAYS ERODED WITH A FLOW OFF THE OCEAN. THE PRESENT TAFS ARE
OPTIMISTIC IN BREAKING STRATUS EARLIER THAN WE HAD BEEN FORECASTING
AND IN NOT FORECASTING MUCH IN THE WAY OF FOG. ALL SITES BREAK OUT
TO VFR BY 16Z IN THE PRESENT TAFS, WITH THE SOUTHEASTERN AND
DELAWARE VALLEY SITES BREAKING OUT DURING THE DAYLIGHT MORNING
HOURS. WE WILL MONITOR.
WE HAVE CONTINUED THE OPTIMISTIC FORECAST INTO THE AFTERNOON BY
ONLY FORECASTING A PROB30 FOR TSTM ACTIVITY AT MOST SITES (NOT THE
SOUTHEASTERN ONES) AND THEN GOING VFR THROUGH 09/06Z (12Z AT
PHL). WE MAY ULTIMATELY INSERT AT LEAST SOME STRATUS INTO THE
FORECAST FOR THE PERIOD AFTER 06Z IN SUBSEQUENT ISSUANCES. WINDS
ARE NOT EXPECTED TO BE A MAIN CONCERN TODAY, BUT THEY SHOULD VEER
FROM EAST OR NORTHEAST TO SOUTHEAST DURING THE TAF PERIOD AT 10 KT
OR LESS.
OUTLOOK...
THU INTO FRI NIGHT...MOSTLY VFR. SCATTERED SHOWERS/TSTMS FRI
AFTERNOON MAY BRING LOWER CIGS/VSBYS.
SAT THRU SUN...LOWER CONDITIONS EXPECTED WITH CIGS/SHOWERS SAT AND
SAT NIGHT. IMPROVING CONDITIONS LATER SUNDAY.
&&
.MARINE...
WITH BROAD LOW PRESSURE APPROACHING OUR REGION AND A CONTINUED
ONSHORE FLOW, SEAS ARE EXPECTED TO BE ELEVATED THROUGH TONIGHT
ON OUR ATLANTIC COASTAL WATERS. A SMALL CRAFT ADVISORY FOR
HAZARDOUS SEAS CONTINUES FOR ALL OF OUR ATLANTIC COASTAL WATERS
THROUGH TONIGHT. SEAS AND WINDS ARE EXPECTED TO REMAIN BELOW SCA
LEVELS FOR DELAWARE BAY. VISIBILITIES WILL BE LOWERED AT TIMES IN
SCATTERED SHOWERS AND ISOLATED THUNDER MAINLY THIS AFTERNOON,
ALTHOUGH NORTHERN ATLANTIC WATERS WILL SEE SOME HEAVIER RAIN AND
PERHAPS SOME THUNDER EARLY THIS MORNING. ANOTHER SHOT OF SHOWER AND
THUNDERSTORM ACTIVITY IS POSSIBLE TONIGHT.
OUTLOOK...SCA CONDITIONS FOR HAZ SEAS WILL PROBABLY COME DOWN THU
MORNING AS THE LONGER PERIOD SWELLS DIMINISH. ANOTHER PERIOD OF
SCA CONDITIONS WILL DEVELOP ACROSS THE OCEAN WATERS FRI NIGHT AND
LAST INTO THE WEEKEND.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT
THURSDAY FOR ANZ450>455.
&&
$$
SYNOPSIS...GIGI/O`HARA
NEAR TERM...DELISI
SHORT TERM...DELISI
LONG TERM...O`HARA
AVIATION...DELISI
MARINE...DELISI
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
900 PM EDT THU MAY 9 2013
.UPDATE (TONIGHT AND FRIDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS THE UPPER LEVEL PATTERN
HAS FLATTENED OUT OVERHEAD...AND EVEN BECOME SLIGHTLY RIDGED OVER
THE PAST 24 HOURS. DRY POCKET WITHIN THE SUBSIDENCE ON THE BACK SIDE
OF THE DEPARTING TROUGH IS NOW EXITING TO OUR EAST WITH MORE
MID/UPPER LEVEL COLUMN MOISTURE BEGINNING TO OVERSPREAD THE
PENINSULA FROM THE WEST. 10/00Z KTBW SOUNDING PROFILE STILL SHOWS
THE INFLUENCE OF THE DRY COLUMN WITH A PW VALUE OF ONLY AROUND
0.72"...AND DECENT DEWPOINT DEPRESSIONS THROUGH THE EXTENT OF THE
TROP.
THETA-E VALUES IN THE MID-LEVELS ARE GENERALLY BELOW 315K AND THIS
REPRESENTS A SIGNIFICANTLY HOSTILE ENVIRONMENT FOR DEEP CONVECTION.
WE SAW THIS ALL DAY...WITH A DECENT SEA-BREEZE CIRCULATION...BUT
ONLY A GENERALLY SHALLOW CU FIELD THAT STRUGGLED TO OBTAIN ANY
VERTICAL EXTENT. BETTER MOISTURE PROFILES WERE SEEN DOWN TOWARD
MIAMI AND FAR SOUTH FLORIDA WHERE A FEW THUNDERSTORMS WERE ABLE TO
TAKE ROOT OVER THE PAST SEVERAL HOURS.
AT THE SURFACE...HIGH PRESSURE RIDGE AXIS EXTENDS ACROSS THE CENTRAL
PORTION OF THE PENINSULA AND EASTERN GULF OF MEXICO. DIURNAL
SEA-BREEZE WILL SETTLE DOWN OVER THE NEXT COUPLE OF HOURS AND WITH
THE VERY LIGHT GRADIENT IN PLACE...SHOULD REVERSE ITSELF AND BECOME
AN OFFSHORE LAND BREEZE DURING THE EARLY MORNING HOURS. TEMPERATURES
WILL COOL THROUGH THE NIGHT REACHING MORNING LOWS AROUND SUNRISE IN
THE LOWER TO MIDDLE 60S FOR MOST SPOTS. AN ISOLATED READING IN THE
UPPER 50S IS POSSIBLE FOR NORMALLY COLDER SPOTS ALONG THE INTERIOR
NATURE COAST.
FRIDAY...A WARM AND INCREASINGLY SUMMER-LIKE DAY TO END OUT THE WORK
WEEK. 850MB TEMPS IN THE 14-16C RANGE SHOULD EASILY MIX OUT INTO THE
MID/UPPER 80S...WITH MANY SPOTS AWAY FROM THE BEACH AND SOUTH OF THE
I-4 CORRIDOR FLIRTING OR BRIEFLY SURPASSING 90. THE WEAK GRADIENT
AND STRONG TERRESTRIAL WARMING SHOULD FORCE ANOTHER DECENT
SEA-BREEZE CIRCULATION FOR THE AFTERNOON THROUGH EARLY EVENING.
ALTHOUGH ENVIRONMENT DOES NOT LOOK "FAVORABLE"...CONDITIONS ARE
CERTAINLY MORE CONDUCIVE THAN WHAT WAS SEEN ON THURSDAY TO ALLOW FOR
A FEW STORMS TO DEVELOP. BEST CHANCES TO SEE A STORM WILL BE ACROSS
THE INTERIOR AND SOUTH OF I-4...AND ALSO MAINLY LATE IN THE DAY
AFTER 20-21Z. MID-LEVEL TEMPS ARE A BIT ON THE COOL SIDE...SO ANY
STORMS THAT CAN GET THEMSELVES ESTABLISHED WITH HAVE THE POTENTIAL
TO BRIEFLY PULSE TO STRONG LEVELS. ENJOY.
&&
.AVIATION...
R CONDITIONS FOR THE NEXT 24 HOURS. THERE MAY BE SOME PATCHY LATE
NIGHT GROUND FOG INLAND...BUT NOT ENOUGH TO IMPACT THE TERMINALS.
LIGHT/VARIABLE WINDS OVERNIGHT SHIFT TO ONSHORE LATE MORNING AND
AFTERNOON.
&&
.MARINE...
HIGH PRESSURE RIDGING ACROSS FLORIDA AND INTO THE EASTERN GULF WILL
KEEP LIGHT AND VARIABLE WINDS OVER THE COASTAL WATERS THROUGH THE
WEEKEND WITH AFTERNOON SEA BREEZES. A FRONTAL BOUNDARY WILL
APPROACH THE REGION EARLY NEXT WEEK WITH CHANCES FOR SHOWERS AND
STORMS WITH INCREASING WINDS AND SEAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 69 87 71 87 / 0 10 0 10
FMY 69 90 71 91 / 0 20 10 20
GIF 68 90 70 90 / 0 30 20 30
SRQ 67 84 70 85 / 0 0 0 10
BKV 58 88 63 88 / 0 10 0 20
SPG 70 86 73 87 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
1052 AM EDT WED MAY 8 2013
.UPDATE...NO CHANGES ARE NEEDED TO THE FORECAST THIS MORNING. THE
MIAMI SOUNDING SHOWS VERY DRY AIR PRESENT WITH A PWAT OF ONLY 0.70
INCHES. MEAN WESTERLY STEERING FLOW CONTINUES, AND BOTH TPA AND
KEY SHOW SLIGHTLY HIGHER MOISTURE IN THE LOWER LEVELS. COULD THIS
BE JUST ENOUGH ADVECTING IN THIS AFTERNOON TO PRODUCE A FEW
SHOWERS? ALL GUIDANCE SAYS NO, EXCEPT HRRR SHOWS A SMALL LIGHT
SHOWER EARLY THIS EVENING OVER INTERIOR PALM BEACH, BUT THAT`S IT.
GIVEN THIS, HAVE OPTED TO KEEP SHOWER MENTION OUT OF THE FORECAST
AS MOST, AND LIKELY ALL, AREAS WILL REMAIN DRY TODAY. PLEASANT LOW
HUMIDITY CONTINUES WITH DEWPOINTS IN THE 50S! /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 730 AM EDT WED MAY 8 2013/
AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD. WINDS
WILL REMAIN VARIABLE ACROSS ALL OF THE SOUTH FLORIDA TERMINALS
THROUGH THE MIDDLE OF WEDNESDAY MORNING. AN EAST COAST SEA BREEZE WILL
DEVELOP AROUND 19-21Z WEDNESDAY BEFORE DIMINISHING WEDNESDAY
EVENING. AT KAPF, WINDS WILL SHIFT TO THE SOUTHWEST AS A WEST
COAST SEA BREEZE DEVELOPS WEDNESDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 322 AM EDT WED MAY 8 2013/
.DISCUSSION...
ANOTHER QUIET...COOL AND DRY EARLY MAY MORNING FOR SOUTH FLORIDA.
AN UPPER LEVEL LOW ACROSS NORTH CAROLINA AND VIRGINIA WILL
FINALLY BEGIN TO MOVE NORTHEAST. SO THE UPPER TROUGH OVER THE
REGION WILL GET REPLACED WITH A MORE ZONAL PATTERN BY THE WEEKEND.
SURFACE HIGH PRESSURE OVER THE REGION WILL ALLOW FOR LIGHT
WINDS...SUNNY SKIES...AND WARM AFTERNOON TEMPERATURES. THE
SUBTROPICAL RIDGE...WHICH WAS LOCATED OVER THE BAHAMAS AND
CUBA...WILL SLOWLY MOVE NORTH TO THE FLORIDA KEYS ON THURSDAY AS THE
UPPER LEVEL LOW MOVES INTO THE NORTHEAST. THIS WILL ALSO BRING A
SMALL INCREASE TO THE LOW LEVEL MOISTURE TO THE REGION. MODELS ARE
INDICATING THAT THE SUBTROPICAL JET WILL MOVE BACK NORTH TOWARDS
SOUTH FLORIDA ONCE AGAIN...AND A WEAK SHORTWAVE MAY MOVE ACROSS THE
REGION THURSDAY AFTERNOON. DRY AIR WILL STILL REMAIN IN THE LOW/MID
LEVELS...SO NO MORE THAN AN ISOLATED SHOWER OR TWO IS EXPECTED.
KEPT A SILENT 10 POP IN PLACE FOR NOW.
THE SURFACE RIDGE AXIS WILL MOVE NORTH OF THE REGION THURSDAY
NIGHT...WITH EASTERLY FLOW RETURNING TO SOUTH FLORIDA. SO THIS WILL
END THE COOLER THAN NORMAL OVERNIGHT TEMPERATURES. LOW PRESSURE IS
FORECAST TO DEVELOP ACROSS THE OHIO VALLEY AND MOVE INTO THE
NORTHEAST ON FRIDAY...AND A CLIPPER SYSTEM WILL MOVE ACROSS THE
NORTHERN TIP OF LAKE SUPERIOR ON SATURDAY. A FEW SHOWERS OR STRAY
THUNDERSTORM COULD DEVELOP ALONG THE INTERIOR FRIDAY AND SATURDAY
ALONG THE SEA BREEZE BOUNDARIES.
A BROAD UPPER TROUGH WILL THEN DEVELOP ACROSS THE GREAT LAKES AND
INTO THE SOUTHEAST ON SUNDAY. A COLD FRONT IS EXPECTED TO PUSH INTO
THE SOUTHEAST AND NORTHERN FLORIDA ON SUNDAY...AND AN AREA OF LOW
PRESSURE MAY ALSO DEVELOP AND MOVE NORTHEAST ALONG THE BOUNDARY. LOW
LEVEL FLOW WILL SHIFT MORE TO THE SOUTH...AND LOW LEVEL MOISTURE
WILL INCREASE ACROSS THE REGION. SO RAIN CHANCES WILL BEGIN TO
INCREASE ON SUNDAY FOR THE AREA. HOWEVER...THE GREATEST CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD WILL BE ON MONDAY AS
THE FRONTAL BOUNDARY MOVES INTO THE REGION. THE FRONT IS
EXPECTED TO MOVE THROUGH THE REGION MONDAY NIGHT INTO TUESDAY
MORNING...WITH DRIER AIR PUSHING INTO SOUTH FLORIDA.
HOWEVER...SHALLOW MOIST NORTHEASTERLY FLOW AROUND SURFACE HIGH
PRESSURE MAY ALLOW FOR A FEW SHOWERS TO PUSH ACROSS THE ATLANTIC
AND INTO SOUTH FLORIDA. TEMPERATURES WILL SLOWLY RISE THROUGH THE
WEEKEND AS HEIGHTS SLOWLY RISE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 83 66 85 72 / 0 0 10 10
FORT LAUDERDALE 84 68 85 74 / 0 0 10 10
MIAMI 86 67 87 74 / 0 0 10 10
NAPLES 79 63 83 68 / 0 0 - 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
215 AM EDT WED MAY 8 2013
.PREV DISCUSSION... /ISSUED 730 PM EDT TUE MAY 7 2013/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
MAIN FORECAST CONCERN IN THE SHORT TERM IS ASSOCIATED WITH SOME
LINGERING MOISTURE AND WEAK VORT MAXS ROTATING AROUND THE PERSISTENT
UPPER LOW CURRENTLY SITUATED ACROSS THE CAROLINAS. SO FAR THIS
AFTERNOON...IT HAS ALLOWED FOR ENHANCED CU FIELD DEVELOPMENT AND
SOME ISOLATED SHOWERS AND STORMS JUST EAST OF THE CWA. THERE IS
ENOUGH ELEVATED INSTABILITY TO MAINTAIN THE LOW END CHANCE FOR
ISOLATED THUNDERSTORMS MAINLY ACROSS PORTIONS OF THE EAST THROUGH
THE REST OF TODAY.
FOR TONIGHT...POPS SHOULD BE ON THE DECREASE ACROSS THE NORTHEAST.
WITH GUIDANCE LIKELY UNDERDOING THE SFC MOISTURE PRESENT FROM RECENT
RAINFALL...THERE IS A GOOD CHANCE FOR FOG DEVELOPMENT UNDER THE CALM
TO LIGHT WINDS IN THE EARLY MORNING HOURS. GUIDANCE IS IN GENERAL
AGREEMENT WITH SOME LOW LEVEL MOISTURE ADVECTING INTO THE FAR
NORTHERN PORTION NEAR 12Z. SHORT RANGE ENSEMBLE RESTRICTED VSBY
PROBS AND RUC CONDENSATION PRESSURE DEFICIT SUPPORT THE GREATEST
CHANCE FOR MORE WIDESPREAD FOG DEVELOPMENT TO BE IN THE FAR NORTH OR
NORTHWEST. CONFIDENCE IS LOW AT THIS POINT ON DENSE FOG DEVELOPMENT
AND WILL MENTION PATCHY FOG AREA-WIDE FOR NOW.
AS UPPER LOW FINALLY BEGINS ITS EXIT NEWD AND WEAK RIDGING
TEMPORARILY BUILDS IN...HAVE TRENDED POPS TO MAINLY BE FOCUSED IN
THE FAR NORTH AND NORTHEAST THROUGH WEDNESDAY NIGHT. FORECAST
MUCAPE VALUES SUGGEST ISOLATED THUNDERSTORM DEVELOPMENT IS
POSSIBLE AGAIN DURING THE AFTERNOON WEDNESDAY.
FOR TEMPS...A GENERAL BLEND IN THE SHORT TERM GUIDANCE LOOKED
REASONABLE AS THE FORECAST AREA SHOULD CONTINUE A GRADUAL WARM-UP
AHEAD OF THE NEXT SYSTEM DURING THE WEEKEND.
BAKER
LONG TERM /THURSDAY THROUGH TUESDAY/...
HAVE MADE NO CHANGES TO THE EXTENDED. MODELS AGREE O BRIEF BREAK
FOR MUCH OF THE CWA WEDNESDAY NIGHT INTO THURSDAY WITH RAIN
CHANCES INCREASING AGAIN ON FRIDAY. SERIES OF SHORT WAVES SHOULD
KEEP CHANCE OF RAIN ACROSS THE FORECAST AREA THROUGH SUNDAY...WITH
DRYING SUNDAY INTO MONDAY WITH PASSAGE OF A SURFACE FRONT. HAVE
INCLUDED THE PREVIOUS LONG TERM DISCUSSION BELOW.
41
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
/ISSUED AT 411 AM EDT TUE MAY 7 2013/
BY WEDNESDAY NIGHT...PESKY UPPER LOW MOVES UP OVER THE MID
ATLANTIC STATES...WITH RESIDUAL MOISTURE ACROSS NORTH AND
NORTHEAST GEORGIA. BRIEF REPRIEVE EXPECTED ACROSS THE REMAINING
CWA THURSDAY INTO FRIDAY AHEAD OF THE NEXT BATCH OF RAIN. EXTENDED
MODELS STILL SHOWING COMBINATION OF ENHANCED MOISTURE FROM DEEP
SOUTHERLY FLOW AND SERIES OF UPPER LEVEL DISTURBANCES WILL BRING
BACK TO THE STATE BY FRIDAY AHEAD OF FRONT PUSHING THROUGH THE
STATE OVER THE WEEKEND. HAVE OPTED TO INCREASE POPS SLIGHTLY
FRIDAY...WITH GOOD CHANCE NORTH WITH SLIGHT CHANCE THROUGH THE
METRO AREA. HAVE CONTINUED WITH INCREASING TREND INTO SATURDAY
WITH LIKELY POPS NORTH AND GOOD CHANCE ACROSS MUCH OF THE REST OF
THE AREA. THUNDERSTORMS LOOK TO BE LIKELY WITH THIS EVENT WITH
GOOD MODEL AGREEMENT WITH THE INSTABILITY...ESPECIALLY SATURDAY.
MODELS CONTINUE TO DIFFER ON THE AMOUNT OF QPF EXPECTED FRIDAY
THROUGH SUNDAY...WITH THE WETTER ECMWF SHOWING LARGE PORTION OF
WESTERN GEORGIA COULD SEE 0.75 TO 1.25 INCHES WITH ISOLATED HIGHER
AMOUNTS...AND THE GFS SHOWING NORTH GEORGIA COULD SEE WIDESPREAD
0.5 INCHES...WITH PORTIONS OF NORTHWEST GEORGIA SEEING UP TO AN
INCH. HAVE GENERALLY GONE WITH THE GFS SOLUTION FOR QPF...WHICH
MAY BE WISHFUL THINKING AFTER THIS VERY WET WEEKEND ACROSS THE
STATE.
NEAR NORMAL TEMPERATURES ARE EXPECTED WEDNESDAY AND THURSDAY
MORNING...WITH WARM UP BY WEDNESDAY AFTERNOON TO ABOVE NORMAL
TEMPERATURES WHICH WILL REMAIN IN PLACE INTO THE WEEKEND. PRECIP
ACTIVITY SATURDAY AND SUNDAY WILL KEEP TEMPERATURES CLOSER TO
SEASONAL.
31
&&
.AVIATION...
06Z UPDATE...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. PATCHY FOG IS
EXPECTED...BUT NOT ANTICIPATED TO IMPACT ANY TAF SITES AT THIS
TIME. WEST WINDS WILL INCREASE TO 8-11KT THROUGH THE DAY...AND
DIMINISH TO 5-8KT BY 00Z.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...EXCEPT MEDIUM CONFIDENCE ON
POTENTIAL FOG DEVELOPMENT THROUGH 12Z.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 78 56 84 58 / 20 10 10 10
ATLANTA 77 59 81 61 / 10 5 10 10
BLAIRSVILLE 71 51 77 55 / 30 20 20 20
CARTERSVILLE 76 54 81 58 / 10 10 10 20
COLUMBUS 80 60 85 60 / 10 5 5 10
GAINESVILLE 74 56 80 59 / 20 20 10 20
MACON 79 56 84 58 / 10 10 5 10
ROME 77 53 83 57 / 10 10 10 20
PEACHTREE CITY 78 53 82 57 / 10 5 5 10
VIDALIA 80 61 85 62 / 10 10 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...31
LONG TERM....39
AVIATION...31
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
852 PM CDT THU MAY 9 2013
.UPDATE...
OVERALL THUNDER THREAT HAS DIMINISHED BUT AN ISOLATED STORM IS
STILL POSSIBLE SOUTH OF THE LOW TRACK FOR THE NEXT FEW HOURS OR
BASICALLY SOUTH OF A LA SALLE TO RENSSELAER LINE. THE LINE OF
STORMS THAT CROSSED THE MISSISSIPPI RIVER HAS WEAKENED BUT IS
HOLDING TOGETHER ENOUGH TO BRING ADDITIONAL RAINFALL WITH IT.
OTHERWISE...SHIELD OF SHOWERS THAT HAS BEEN AFFECTING THE CWA
SINCE MID AFTERNOON HAS EXPANDED ON ITS SOUTHWEST FLANK AND
CONTINUES TO PIVOT NORTHEASTWARD. THE MAIN THREAT OVERALL WILL BE
BE SPOTTY CORRIDORS OF HEAVIER RAINFALL WITH ONE HOUR RADAR
ESTIMATES IN THE QUARTER TO HALF INCH RANGE. THE BULK OF THE
ACTIVITY IS ON TRACK TO BE OUT OF THE AREA BY 09Z OR SO BUT THE
MAIN UPPER TROUGH AXIS ITSELF WILL BE MOVING ACROSS THE AREA WITH
ENOUGH FORCING EXTENDING INTO THE NORTHERN CWA TO KEEP A HIGHER
CHANCE FOR SHOWERS THERE...BUT WILL LIKELY LOWER POPS ACROSS
CENTRAL AND SOUTHERN AREAS LATE TONIGHT. WIND/TEMP TRENDS REMAIN A
CHALLENGE WITH THE SURFACE LOW NEAR THE QUAD CITIES. EASTWARD
EXTENDING WARM FRONTAL BOUNDARY THAT WAS JUST NORTH OF THE AREA
EARLIER HAS RETREATED SOUTH DOWN THE LAKE AND STRETCHES FROM NEAR
OR JUST NORTHEAST OF RFD ACROSS THE SOUTHERN CHICAGO METRO AREA.
PRESSURE FALLS ARE FOCUSED NEAR LAFAYETTE WHICH COMBINED WITH THE
PLACEMENT OF THE BOUNDARY SUPPORTS AN EAST OR EAST-SOUTHEAST
MOVEMENT TO THE SURFACE LOW...HOWEVER THE EAST-NORTHEAST TRACK OF
THE PARENT UPPER LOW MAY LIMIT THE SOUTHWARD COMPONENT OF THE
SURFACE LOW MOVEMENT. THE 00Z RAP HAS COME MORE IN LINE WITH THIS
IDEA...TAKING THE SFC LOW FURTHER SOUTH THAN ITS PREVIOUS RUNS.
ULTIMATELY THE BOUNDARY MAY STALL ALONG THE INTERSTATE 80 CORRIDOR
OR EVEN JUST A BIT TO THE NORTH AS THE SURFACE LOW AND UPPER
TROUGH PASS...DELAYING THE SHIFT TO NORTH AND NORTHWEST WINDS
ACROSS THE SOUTHEAST CWA AND PERHAPS THE INDIANA SHORELINE OF LAKE
MICHIGAN UNTIL AFTER DAYBREAK FRIDAY. HAVE ADJUSTED WIND AND TEMP
GRIDS TO REFLECT A SLOWER SHIFT ACROSS THESE AREAS BUT FURTHER
ADJUSTMENTS MAY BE NEEDED.
MDB
&&
.DISCUSSION...
322 PM CDT
SHORT TERM...TONIGHT THROUGH SUNDAY
CONCERNS IN THIS PERIOD ARE WITH RAIN AND THUNDER CHANCES
TONIGHT...FOLLOWED BY TEMPERATURES SATURDAY NIGHT AND SUNDAY AS
THERE WILL BE A SIGNIFICANT COOL DOWN.
TONIGHT...WEAK SURFACE LOW WILL TRACK FROM WESTERN ILLINOIS TO
NORTHERN INDIANA AND THEN TO SOUTHWEST LWR MI BY EARLY
FRIDAY...WITH OPEN UPPER WAVE ALSO PUSHING ACROSS REGION. AS THIS
OCCURS... WIDESPREAD SHRA WITH SOME EMBEDDED THUNDER INITIALLY
WILL LIFT NORTHEAST WITH CONVECTIVE ACTIVITY DIMINISHING AS
ELEVATED INSTABILITY DIMINISHES WITH TIME. PWAT OF 1.3 TO 1.4
INCHES AND GOOD MOISTURE TRANSPORT AND CONVERGENCE WILL SUPPORT
EFFICIENT RAINFALL PRODUCTION AND THUS CANT RULE OUT MODERATE TO
OCCASIONALLY HEAVY RAIN RATES UNTIL THE LATE EVENING. AS LOW
TRACKS ACROSS AREA...QUASI STATIONARY FRONT THAT HAS BEEN LAID OUT
ACROSS AREA THIS AFTERNOON WILL PUSH SOUTH AS A COLD FRONT THROUGH
ALL BUT SOUTHEASTERN CWA...WITH COOLER AIR MASS/IN THE 40S TO
LOWER 50S FILTERING IN BY EARLY FRIDAY.
MOST SHRA ACTIVITY SHOULD BE ISOLATED AT BEST ON FRIDAY...EXCEPT FOR
PERHAPS MORE SCATTERED SHRA AHEAD OF FRONT AS IT FINALLY CLEARS OUR
FAR SOUTHEAST BY EARLY AFTERNOON. MILDER START IN THIS AREA COULD
ALLOW HIGHS TO REACH MID TO UPPER 60S...WITH REST OF AREA AWAY FROM
LAKE GENERALLY IN THE LOWER 60S. BIG STORY FRIDAY WILL BE THE STRONG
PUSH OF NORTHERLY WINDS DOWN THE LENGTH OF LAKE MICHIGAN BRINGING
QUITE A CHILLY DAY...WITH HIGHS ONLY AROUND 50 AND WINDS GUSTING AS
HIGH AS 30 MPH.
FRIDAY NIGHT WILL BE DRY AND COOL WITH LOWS IN THE 40S...BUT
AN UNSEASONABLY DEEP UPPER TROUGH WILL PUSH INTO THE UPPER GREAT
LAKES REGION BY SATURDAY...WITH A STRONG COLD FRONT TRAILING FROM
SURFACE LOW PRESSURE. THIS FRONT SHOULD TOUCH OFF A FEW SCT SHRA AS
IT PUSHES THROUGH THE CWA ON SATURDAY DUE TO STEEPENING LOW LEVEL
LAPSE RATES...BUT THE MAIN FOCUS WILL BE THE 850 MB TEMPS COOLING TO
-3C TO -4C BY EARLY SUNDAY...LEAVING A COOL BUT MOSTLY SUNNY MOTHERS
DAY. SOME CONCERN WITH FROST POTENTIAL AS EARLY AS SATURDAY
NIGHT...BUT HIGH PRESSURE SHOULD BE FAR ENOUGH WEST TO MAINTAIN A
GRADIENT AND PRECLUDE FROST FORMATION. ACTUALLY A BIGGER CONCERN
SATURDAY NIGHT IS THAT WHETHER THERE IS FROST OR NOT...AIR TEMPS IN
OUTLYING AREAS COULD DIP TO OR BELOW FREEZING IN UNSEASONABLY COOL
AND DRY AIR MASS IN PLACE. IF THE SUB FREEZING TEMPS REALIZED ON
SOME GUIDANCE IS REALIZED...MAY NEED A FREEZE WATCH FOR PORTIONS OF
AREA SATURDAY NIGHT...AS WE ARE QUICKLY TRENDING TO FULL VEGETATION.
DESPITE FULL SUNSHINE ON MOTHERS DAY...CLIMO WITH 850 TEMPS SUBZERO
C ONLY SUPPORTS HIGHS IN THE MID TO UPPER 50S.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...
CONCERNS IN THE LONG TERM WILL RAPIDLY SHIFT FROM COLD WEATHER
CONCERNS INITIALLY TO VERY WARM TEMPERATURES ON TUESDAY. HIGH
PRESSURE RIDGE AXIS WILL BE OVER THE REGION SUNDAY NIGHT YIELDING
MUCH LIGHTER WINDS. COUPLED WITH CLEAR SKIES AND DRY AIR MASS...WITH
DEW POINTS ONLY AROUND 30...STAGE COULD BE SET FOR LOWS NEAR FREEZING
IN SOME AREAS EARLY MONDAY AND ALSO FROST POTENTIAL. AGAIN LOWERED
TEMPS FROM BLEND OF PREVIOUS FCST AND CONSENSUS GUIDANCE TO
GENERALLY MID 30S EXCEPT RIGHT IN THE CHICAGO HEAT ISLAND...WITH
NEAR FREEZING TEMPS IN TYPICALLY COLDER RURAL AND SUBURBAN LOCATIONS
WEST OF THE FOX RIVER. WILL ADD PATCHY FROST TO THE GRIDS FOR AREAS
AWAY FROM CHICAGO.
THEN EARLY NEXT WEEK...UPPER LEVEL RIDGE QUICKLY AMPLIFIES OVER THE
AREA...WITH RAPIDLY WARMING TEMPS ALOFT. ON MONDAY...HIGHS WILL WARM
NICELY TO THE MID 60S AFTER THE CHILLY START. THEN TUES...850 TEMPS
SOAR TO 18+ TO +20C OR HIGHER (NEW ECMWF HAS +23C! OVER NORTH
CENTRAL IL BY 00Z WEDS) IN GUSTY SOUTHWESTERLY BDRY LAYER FLOW. 850
MB CLIMO WOULD SUGGEST MID 80S AT A MINIMUM IN MID MAY WITH
THESE TEMPS ALOFT. FCST SOUNDINGS SUGGEST HOW DEEP WE MIX COULD
BE A LIMITING FACTOR/IE. TO AROUND 900 MB ON THE GFS AND ECMWF.
AGAIN BUMPED TEMPERATURES UP FROM PREVIOUS FCST AND CONSENSUS BLEND
TO LOW TO MID 80S AND EVEN THIS COULD BE CONSERVATIVE WITH SUCH A
WARM AIR MASS IN PLACE ASSUMING THERE ARE NO LINGERING ISSUES WITH
WAA CLOUD COVER. EXTENDED GUIDANCE CONSISTENT IN FEATURING COLD
FRONT SLIPPING SOUTH INTO PORTION OF AREA ON WEDNESDAY...THOUGH
IT APPEARS IT WILL BE ANOTHER WARM DAY WITH HIGHS AT LEAST INTO
THE UPPER 70S TO AROUND 80. THERE ARE SOME DIFFERENCES ON
SHRA/TSRA CHANCES WITH THIS FRONT...AS NORTHERN CWA COULD BE
FAVORED WEDS AFTERNOON WITH BETTER CHANCES BY WEDNESDAY NIGHT.
GUIDANCE THEN DIVERGES ON HOW FAST FRONT PUSHES THROUGH AREA...AS
IT COULD STALL OUT THURSDAY AND EVEN INTO FRIDAY...KEEPING SHRA
AND TSRA CHANCES GOING.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* -RA/-SHRA THIS EVEN INTO OVERNIGHT.
* SE SFC WINDS BECOMING NE THIS EVE.
* VFR CIGS LOWERING TO MVFR THIS EVE AN PERSISTING THROUGH
MOST/ALL OF DAYTIME FRI.
* SLGT CHC -SHRA DURING DAT FRI.
TRS
//DISCUSSION...UPDATED 00Z...
AS AN UPPER LOW LIFTING NE FROM PA TO SOUTHERN NEW ENGLAND
DURING THE DAY THE UPPER RIDGE AXIS FOLLOWING THE UPPER LOW HAS
BEEN GRADUALLY SHIFTING E TO THE CENTRAL GREAT LAKES AND MID OH
VALLEY DURING THE DAY AND EARLY THIS EVENING...WITH A TRIO OF
DISTURBANCES UPSTREAM OF THE LOCAL AREA.
THE FIRST HAD MOVED FROM NW IA ENE TO SW WI AND FAR SE MN WHILE
THE SECOND...LIKELY GENERATED BY A CONVECTIVE COMPLEX THAT WAS
OVER SE KS AND NE OK AT DAYBREAK...HAD LIFTED NE ACROSS MO TO FAR
NW MO AND FAR SE IA AT 00Z....WHILE THE THIRD MOVED ENE FROM MO
ACROSS CENTRAL IL.
AS THE FIRST DISTURBANCE CONTINUED TO THE ENE IT SPREAD AN AREA
OF STRATIFORM RAIN ACROSS WI WHILE THE SECOND HAS SPAWNED
CONVECTION FROM FAR SE IA AND FAT W CENTRAL IL BACK ACROSS MO AND
THE THIRD A COUPLE CLUSTERS OF THUNDERSTORMS FROM E CENTRAL MO
ACROSS CENTRAL AND SOUTHERN IL TO CENTRAL AND SOUTHERN IN. THIS
HAS LEFT THE LOCAL AREA WIT JUST MAINLY -SHRA THOUGH A FEW
STRONGER CONVECTIVE CELLS HAD BEEN MOVING NE FROM E CENTRAL IL
INTO W CENTRAL IN WITH A FEW LIGHTNING STRIKES DETECTED. FOR THE
ORD AND MDW VC ONLY ANTICIPATE CONTINUED -SHRA INTO THE LATE
NIGHT DUE TO A LACK OF SIGNIFICANT FORCING AND NO ELEVATED CAPE
TO BE UNLEASHED FOR STRONGER VERTICAL DEVELOPMENT.
POSITIVELY TILTED MID AND UPPER TROUGH AXIS IS PROGGED TO MOVE
OVER THE WESTERN GREAT LAKES AND MID MS VALLEY DURING FRI
AFTERNOON...WITH THE ASSOCIATED LOW TO TRACK FROM E CENTRAL IA
ESE...CROSSING THE NW CORNER OF OVERNIGHT AND REACHING FAR
SOUTHERN LOWER MI BY 10.12Z. THE ESE PROGGED MOVEMENT OF THE LOW
LOOKS TO BE ON TRACK AS GREATEST SURFACE PRESSURE FALLS ARE TO
THE ESE THROUGH SE OF THE CURRENT POSITION OF THE LOW. WHILE SOME
-SHRA ARE POSSIBLE AS THE MID/UPPER TROUGH PASSES BY THE THREAT
LOOKS TO BE LOW ENOUGH TO NOT MENTION IN THE TAFOR AT THIS TIME.
AS THE LOW MOVES JUST S OF ORD AND MDW TONIGHT WINDS...WHICH HAVE
ALREADY BACKED FROM S TO NE AT ORD AS THE COLD WATER AND LESSER
FRICTION OF THE LAKE SURFACE HAS ALLOWED THAT PORTION OF THE
FRONTAL BOUNDARY TO SLIDE DOWN TO ALMOST TO THE FAR SOUTHERN
PORTION OF THE LAKE. WINDS WILL CONTINUE TO BACK WITH N TO NNW
WINDS EXPECTED BY PREDAWN/EARLY MORNING FRI AS THE LOW IS TO HAVE
MOVED OFF THE THE ENE BY THEN.
A LARGE AREA MVFR...AND SOME IFR CIGS...EXTENDS FROM NORTHERN AND
WESTERN WI BACK ACROSS SE AND S CENTRAL MN...NORTHERN AND WESTERN
IA TO EASTERN AND S CENTRAL NE BEHIND THE SURFACE FRONT. MODELS
KEEP THIS LEVER LEVEL MOISTURE AND CLOUDINESS OVER THE LOCAL AREA
THROUGH MOST ALL OF THE DAY FRI BEFORE A RETURN TO VFR
CONDITIONS.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MODERATE CONFIDENCE ALL PARAMETERS TONIGHT THROUGH FRI...EXCEPT
LOW CONFIDENCE ON CLOUD HEIGHTS/ENDING OF MVFR CIGS DURING LATE
FRI.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z SAT-12Z THU...UPDATED 00Z...
SAT...CHANCE SHRA.
SUN THROUGH TUE...VFR...WX NIL.
WED...CHANCE TSRA.
TRS
&&
.MARINE...
236 PM CDT
A SLOW MOVING COLD FRONT CONTINUES TO SAG SOUTH ACROSS LAKE
MICHIGAN THIS AFTERNOON. AN AREA OF LOW PRESSURE CENTERED NEAR
SOUTHEAST IOWA THIS AFTERNOON WILL LIFT NORTHEAST ALONG THIS
FRONTAL BOUNDARY...INTO NORTHERN ILLINOIS. THEN THE LOW PRESSURE
WILL CONTINUE TO SLIDE EAST ACROSS NORTHERN ILLINOIS FRIDAY
MORNING. MEANWHILE...THE GRADIENT BEHIND THE FRONTAL BOUNDARY WILL
TIGHTEN OVER THE NORTHERN PORTION OF THE LAKE...ALLOWING
NORTH/NORTHEAST WINDS TO INCREASE TO 15 TO 25 KT WITH OCCASIONAL
GUSTS TO 30 KT. THE NORTH WINDS WILL EVENTUALLY REACH THE SOUTHERN
PORTION OF LAKE MICHIGAN...ALLOWING FOR A LONG FETCH TO SETUP.
THIS POINTS TOWARDS BUILDING WAVES FOR THE SOUTHERN TIP OF THE
LAKE...INCLUDING BOTH THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS. HAVE HOISTED A SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
HAZARDOUS WINDS/WAVES OVERNIGHT...ACROSS ILLINOIS NEARSHORE ZONES
FIRST...THEN REACHING NORTHWEST INDIANA NEARSHORE WATERS FRIDAY
MORNING.
WAVES WILL REMAIN HAZARDOUS THROUGH MUCH OF THE DAY
FRIDAY...DESPITE SLOWLY DIMINISHING WINDS AS A WEAK AREA OF HIGH
PRESSURE BUILDS OVER THE LAKE FRIDAY EVENING THROUGH EARLY
SATURDAY. THEN ANOTHER STRONG COLD FRONT WILL SLIDE EAST ACROSS
THE UPPER MIDWEST EARLY SATURDAY...REACHING LAKE MICHIGAN BY
MIDDAY. THIS WILL BRING ANOTHER TIGHT GRADIENT AND A RETURN TO
GUSTY NORTHWEST WINDS. AT THIS TIME GUSTS SHOULD BE AROUND 30
KT...HOWEVER A FEW GALE FORCE GUSTS MAY OCCUR.
LIGHT AND VARIABLE WINDS SET UP AGAIN FOR LATE SUNDAY INTO
MONDAY...AS ANOTHER AREA OF HIGH PRESSURE BUILDS ACROSS THE
WESTERN LAKES. THIS HIGH SHIFTS EAST MONDAY NIGHT...WITH YET
ANOTHER SHARP PRESSURE GRADIENT DEVELOPING ACROSS THE WESTERN
LAKES TUESDAY WITH A POTENT STORM SYSTEM SLIDING EAST ACROSS
ONTARIO TUESDAY. THIS WILL ALLOW STRONG SOUTHERLY WINDS AHEAD OF
THE FRONTAL BOUNDARY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
824 PM CDT THU MAY 9 2013
.MESOSCALE DISCUSSION...
620 PM CDT
CONTINUING TO WATCH CONVECTIVE TRENDS THROUGH THE EVENING HOURS AS
BANDS OF RAIN CURRENTLY LIFT ACROSS THE CWA THANKS TO MOIST WARM
ADVECTION. SATELLITE IMAGERY SHOWS A SLIVER OF CLEARING THAT
DEVELOPED RIGHT ALONG THE MISSISSIPPI RIVER FROM THE QUAD CITIES
ON SOUTH IN CONJUNCTION WITH A SURFACE TROUGH/COOL FRONT WITH A
MORE SIZABLE AREA OF CLEARING FROM MACOMB SOUTH TO THE ST. LOUIS
AREA. A NARROW LINE OF STORMS HAS FIRED AND IS JUST EAST OF THE
RIVER FROM THE QUAD CITIES SOUTH AT 23Z. 23Z SFC OBS SHOW THE
CENTER OF THE SFC LOW NEAR MUSCATINE WITH PRESSURE FALLS FOCUSED
NEAR DECATUR BUT STEADILY SPREADING NORTHWARD ACROSS THE I-80
CORRIDOR. NEAR TERM GUIDANCE IS HAVING A TOUGH TIME AGREEING ON
THE PATH OF THE LOW WITH THE RAP BEING THE FURTHER NORTH OUTLIER
AMONG HIGH RES GUIDANCE. THERE IS SOME SUPPORT FOR AT LEAST A
SLIGHTLY FURTHER NORTH TRACK...GIVEN THE PRESSURE FALLS DEVELOPING
NORTH AND SOUTH WINDS CURRENTLY IN PLACE ACROSS THE ENTIRE CWA
MINUS THE EXTREME NE CORNER. A FURTHER SOUTH TRACK WOULD QUICKLY
ALLOW WINDS TO TURN EAST AND NORTHEAST ACROSS MOST OF THE AREA
THIS EVENING WOULD SUPPORT A MINIMAL THUNDER THREAT...WITH THE
FURTHER NORTH TRACK MORE SUPPORTIVE OF A STILL LOW BUT SLIGHTLY
INCREASED STRONG TS THREAT. WITH ALL OF THIS IN MIND EXPECT THAT
THE NARROW LINE OF STORMS WILL CONTINUE EASTWARD WITH THE
INSTABILITY AXIS SPREADING A BIT MORE NORTH AND EAST OVER THE NEXT
1-2 HOURS HELPING TO KEEP THE LINE GOING. WITH SUNSET APPROACHING
HAVE A HARD TIME SEEING ANY KIND OF INCREASE OR EVEN MAINTENANCE
OF STRONGER CONVECTION ESPECIALLY GIVEN THAT IT WILL BE MOVING
FURTHER INTO THE CWA WHERE THINGS ARE ALREADY QUITE
STABLE...BUT AREAS NEAR THE WESTERN CWA BORDER FROM ABOUT LA
SALLE TO WEST OF PONTIAC STAND A CHANCE OF SEEING THIS ACTIVITY A
COUPLE HOURS FROM NOW. HEAVY RAIN LOOKS TO BE THE MAIN THREAT
OVERALL WITH THE MOIST ATMOSPHERE AND LOW LEVEL...BUT SOME SMALL
HAIL OR SOME STRONGER WINDS COULD OCCUR BUT SEEM UNLIKELY OVERALL.
DEEP LAYER SHEAR IS ONLY AROUND 30 KT OR SO BASED ON THE SPC
MESOANLYSIS BUT HAVE SEEN SOME WEAK LOW LEVEL CIRCULATIONS ON THE
KDVN RADAR DUE TO STRONG LOW LEVEL CAPE AND LOW LEVEL VORTICITY
ALONG THE BOUNDARY SO WILL NEED TO KEEP AN EYE ON THIS AS IT MOVES
EAST. OUTSIDE OF THE TS POTENTIAL...WINDS WILL BE PROBLEMATIC
GIVEN THE LOW PASSING NEARBY BUT AM THINKING THAT THE PUSH OF
NORTH-NORTHEAST WINDS WILL INCREASE IN SPEED AS THE SUN SETS AND
THE LAKE CAN GAIN INFLUENCE...ULTIMATELY KEEPING THE LOW AT LEAST
SOMEWHAT FURTHER SOUTH THAN WHAT THE RECENT RAP RUNS HAVE
SUGGESTED.
MDB
&&
.DISCUSSION...
322 PM CDT
SHORT TERM...TONIGHT THROUGH SUNDAY
CONCERNS IN THIS PERIOD ARE WITH RAIN AND THUNDER CHANCES
TONIGHT...FOLLOWED BY TEMPERATURES SATURDAY NIGHT AND SUNDAY AS
THERE WILL BE A SIGNIFICANT COOL DOWN.
TONIGHT...WEAK SURFACE LOW WILL TRACK FROM WESTERN ILLINOIS TO
NORTHERN INDIANA AND THEN TO SOUTHWEST LWR MI BY EARLY
FRIDAY...WITH OPEN UPPER WAVE ALSO PUSHING ACROSS REGION. AS THIS
OCCURS... WIDESPREAD SHRA WITH SOME EMBEDDED THUNDER INITIALLY
WILL LIFT NORTHEAST WITH CONVECTIVE ACTIVITY DIMINISHING AS
ELEVATED INSTABILITY DIMINISHES WITH TIME. PWAT OF 1.3 TO 1.4
INCHES AND GOOD MOISTURE TRANSPORT AND CONVERGENCE WILL SUPPORT
EFFICIENT RAINFALL PRODUCTION AND THUS CANT RULE OUT MODERATE TO
OCCASIONALLY HEAVY RAIN RATES UNTIL THE LATE EVENING. AS LOW
TRACKS ACROSS AREA...QUASI STATIONARY FRONT THAT HAS BEEN LAID OUT
ACROSS AREA THIS AFTERNOON WILL PUSH SOUTH AS A COLD FRONT THROUGH
ALL BUT SOUTHEASTERN CWA...WITH COOLER AIR MASS/IN THE 40S TO
LOWER 50S FILTERING IN BY EARLY FRIDAY.
MOST SHRA ACTIVITY SHOULD BE ISOLATED AT BEST ON FRIDAY...EXCEPT FOR
PERHAPS MORE SCATTERED SHRA AHEAD OF FRONT AS IT FINALLY CLEARS OUR
FAR SOUTHEAST BY EARLY AFTERNOON. MILDER START IN THIS AREA COULD
ALLOW HIGHS TO REACH MID TO UPPER 60S...WITH REST OF AREA AWAY FROM
LAKE GENERALLY IN THE LOWER 60S. BIG STORY FRIDAY WILL BE THE STRONG
PUSH OF NORTHERLY WINDS DOWN THE LENGTH OF LAKE MICHIGAN BRINGING
QUITE A CHILLY DAY...WITH HIGHS ONLY AROUND 50 AND WINDS GUSTING AS
HIGH AS 30 MPH.
FRIDAY NIGHT WILL BE DRY AND COOL WITH LOWS IN THE 40S...BUT
AN UNSEASONABLY DEEP UPPER TROUGH WILL PUSH INTO THE UPPER GREAT
LAKES REGION BY SATURDAY...WITH A STRONG COLD FRONT TRAILING FROM
SURFACE LOW PRESSURE. THIS FRONT SHOULD TOUCH OFF A FEW SCT SHRA AS
IT PUSHES THROUGH THE CWA ON SATURDAY DUE TO STEEPENING LOW LEVEL
LAPSE RATES...BUT THE MAIN FOCUS WILL BE THE 850 MB TEMPS COOLING TO
-3C TO -4C BY EARLY SUNDAY...LEAVING A COOL BUT MOSTLY SUNNY MOTHERS
DAY. SOME CONCERN WITH FROST POTENTIAL AS EARLY AS SATURDAY
NIGHT...BUT HIGH PRESSURE SHOULD BE FAR ENOUGH WEST TO MAINTAIN A
GRADIENT AND PRECLUDE FROST FORMATION. ACTUALLY A BIGGER CONCERN
SATURDAY NIGHT IS THAT WHETHER THERE IS FROST OR NOT...AIR TEMPS IN
OUTLYING AREAS COULD DIP TO OR BELOW FREEZING IN UNSEASONABLY COOL
AND DRY AIR MASS IN PLACE. IF THE SUB FREEZING TEMPS REALIZED ON
SOME GUIDANCE IS REALIZED...MAY NEED A FREEZE WATCH FOR PORTIONS OF
AREA SATURDAY NIGHT...AS WE ARE QUICKLY TRENDING TO FULL VEGETATION.
DESPITE FULL SUNSHINE ON MOTHERS DAY...CLIMO WITH 850 TEMPS SUBZERO
C ONLY SUPPORTS HIGHS IN THE MID TO UPPER 50S.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...
CONCERNS IN THE LONG TERM WILL RAPIDLY SHIFT FROM COLD WEATHER
CONCERNS INITIALLY TO VERY WARM TEMPERATURES ON TUESDAY. HIGH
PRESSURE RIDGE AXIS WILL BE OVER THE REGION SUNDAY NIGHT YIELDING
MUCH LIGHTER WINDS. COUPLED WITH CLEAR SKIES AND DRY AIR MASS...WITH
DEW POINTS ONLY AROUND 30...STAGE COULD BE SET FOR LOWS NEAR FREEZING
IN SOME AREAS EARLY MONDAY AND ALSO FROST POTENTIAL. AGAIN LOWERED
TEMPS FROM BLEND OF PREVIOUS FCST AND CONSENSUS GUIDANCE TO
GENERALLY MID 30S EXCEPT RIGHT IN THE CHICAGO HEAT ISLAND...WITH
NEAR FREEZING TEMPS IN TYPICALLY COLDER RURAL AND SUBURBAN LOCATIONS
WEST OF THE FOX RIVER. WILL ADD PATCHY FROST TO THE GRIDS FOR AREAS
AWAY FROM CHICAGO.
THEN EARLY NEXT WEEK...UPPER LEVEL RIDGE QUICKLY AMPLIFIES OVER THE
AREA...WITH RAPIDLY WARMING TEMPS ALOFT. ON MONDAY...HIGHS WILL WARM
NICELY TO THE MID 60S AFTER THE CHILLY START. THEN TUES...850 TEMPS
SOAR TO 18+ TO +20C OR HIGHER (NEW ECMWF HAS +23C! OVER NORTH
CENTRAL IL BY 00Z WEDS) IN GUSTY SOUTHWESTERLY BDRY LAYER FLOW. 850
MB CLIMO WOULD SUGGEST MID 80S AT A MINIMUM IN MID MAY WITH
THESE TEMPS ALOFT. FCST SOUNDINGS SUGGEST HOW DEEP WE MIX COULD
BE A LIMITING FACTOR/IE. TO AROUND 900 MB ON THE GFS AND ECMWF.
AGAIN BUMPED TEMPERATURES UP FROM PREVIOUS FCST AND CONSENSUS BLEND
TO LOW TO MID 80S AND EVEN THIS COULD BE CONSERVATIVE WITH SUCH A
WARM AIR MASS IN PLACE ASSUMING THERE ARE NO LINGERING ISSUES WITH
WAA CLOUD COVER. EXTENDED GUIDANCE CONSISTENT IN FEATURING COLD
FRONT SLIPPING SOUTH INTO PORTION OF AREA ON WEDNESDAY...THOUGH
IT APPEARS IT WILL BE ANOTHER WARM DAY WITH HIGHS AT LEAST INTO
THE UPPER 70S TO AROUND 80. THERE ARE SOME DIFFERENCES ON
SHRA/TSRA CHANCES WITH THIS FRONT...AS NORTHERN CWA COULD BE
FAVORED WEDS AFTERNOON WITH BETTER CHANCES BY WEDNESDAY NIGHT.
GUIDANCE THEN DIVERGES ON HOW FAST FRONT PUSHES THROUGH AREA...AS
IT COULD STALL OUT THURSDAY AND EVEN INTO FRIDAY...KEEPING SHRA
AND TSRA CHANCES GOING.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* -RA/-SHRA THIS EVEN INTO OVERNIGHT.
* SE SFC WINDS BECOMING NE THIS EVE.
* VFR CIGS LOWERING TO MVFR THIS EVE AN PERSISTING THROUGH
MOST/ALL OF DAYTIME FRI.
* SLGT CHC -SHRA DURING DAT FRI.
TRS
//DISCUSSION...UPDATED 00Z...
AS AN UPPER LOW LIFTING NE FROM PA TO SOUTHERN NEW ENGLAND
DURING THE DAY THE UPPER RIDGE AXIS FOLLOWING THE UPPER LOW HAS
BEEN GRADUALLY SHIFTING E TO THE CENTRAL GREAT LAKES AND MID OH
VALLEY DURING THE DAY AND EARLY THIS EVENING...WITH A TRIO OF
DISTURBANCES UPSTREAM OF THE LOCAL AREA.
THE FIRST HAD MOVED FROM NW IA ENE TO SW WI AND FAR SE MN WHILE
THE SECOND...LIKELY GENERATED BY A CONVECTIVE COMPLEX THAT WAS
OVER SE KS AND NE OK AT DAYBREAK...HAD LIFTED NE ACROSS MO TO FAR
NW MO AND FAR SE IA AT 00Z....WHILE THE THIRD MOVED ENE FROM MO
ACROSS CENTRAL IL.
AS THE FIRST DISTURBANCE CONTINUED TO THE ENE IT SPREAD AN AREA
OF STRATIFORM RAIN ACROSS WI WHILE THE SECOND HAS SPAWNED
CONVECTION FROM FAR SE IA AND FAT W CENTRAL IL BACK ACROSS MO AND
THE THIRD A COUPLE CLUSTERS OF THUNDERSTORMS FROM E CENTRAL MO
ACROSS CENTRAL AND SOUTHERN IL TO CENTRAL AND SOUTHERN IN. THIS
HAS LEFT THE LOCAL AREA WIT JUST MAINLY -SHRA THOUGH A FEW
STRONGER CONVECTIVE CELLS HAD BEEN MOVING NE FROM E CENTRAL IL
INTO W CENTRAL IN WITH A FEW LIGHTNING STRIKES DETECTED. FOR THE
ORD AND MDW VC ONLY ANTICIPATE CONTINUED -SHRA INTO THE LATE
NIGHT DUE TO A LACK OF SIGNIFICANT FORCING AND NO ELEVATED CAPE
TO BE UNLEASHED FOR STRONGER VERTICAL DEVELOPMENT.
POSITIVELY TILTED MID AND UPPER TROUGH AXIS IS PROGGED TO MOVE
OVER THE WESTERN GREAT LAKES AND MID MS VALLEY DURING FRI
AFTERNOON...WITH THE ASSOCIATED LOW TO TRACK FROM E CENTRAL IA
ESE...CROSSING THE NW CORNER OF OVERNIGHT AND REACHING FAR
SOUTHERN LOWER MI BY 10.12Z. THE ESE PROGGED MOVEMENT OF THE LOW
LOOKS TO BE ON TRACK AS GREATEST SURFACE PRESSURE FALLS ARE TO
THE ESE THROUGH SE OF THE CURRENT POSITION OF THE LOW. WHILE SOME
-SHRA ARE POSSIBLE AS THE MID/UPPER TROUGH PASSES BY THE THREAT
LOOKS TO BE LOW ENOUGH TO NOT MENTION IN THE TAFOR AT THIS TIME.
AS THE LOW MOVES JUST S OF ORD AND MDW TONIGHT WINDS...WHICH HAVE
ALREADY BACKED FROM S TO NE AT ORD AS THE COLD WATER AND LESSER
FRICTION OF THE LAKE SURFACE HAS ALLOWED THAT PORTION OF THE
FRONTAL BOUNDARY TO SLIDE DOWN TO ALMOST TO THE FAR SOUTHERN
PORTION OF THE LAKE. WINDS WILL CONTINUE TO BACK WITH N TO NNW
WINDS EXPECTED BY PREDAWN/EARLY MORNING FRI AS THE LOW IS TO HAVE
MOVED OFF THE THE ENE BY THEN.
A LARGE AREA MVFR...AND SOME IFR CIGS...EXTENDS FROM NORTHERN AND
WESTERN WI BACK ACROSS SE AND S CENTRAL MN...NORTHERN AND WESTERN
IA TO EASTERN AND S CENTRAL NE BEHIND THE SURFACE FRONT. MODELS
KEEP THIS LEVER LEVEL MOISTURE AND CLOUDINESS OVER THE LOCAL AREA
THROUGH MOST ALL OF THE DAY FRI BEFORE A RETURN TO VFR
CONDITIONS.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MODERATE CONFIDENCE ALL PARAMETERS TONIGHT THROUGH FRI...EXCEPT
LOW CONFIDENCE ON CLOUD HEIGHTS/ENDING OF MVFR CIGS DURING LATE
FRI.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z SAT-12Z THU...UPDATED 00Z...
SAT...CHANCE SHRA.
SUN THROUGH TUE...VFR...WX NIL.
WED...CHANCE TSRA.
TRS
&&
.MARINE...
236 PM CDT
A SLOW MOVING COLD FRONT CONTINUES TO SAG SOUTH ACROSS LAKE
MICHIGAN THIS AFTERNOON. AN AREA OF LOW PRESSURE CENTERED NEAR
SOUTHEAST IOWA THIS AFTERNOON WILL LIFT NORTHEAST ALONG THIS
FRONTAL BOUNDARY...INTO NORTHERN ILLINOIS. THEN THE LOW PRESSURE
WILL CONTINUE TO SLIDE EAST ACROSS NORTHERN ILLINOIS FRIDAY
MORNING. MEANWHILE...THE GRADIENT BEHIND THE FRONTAL BOUNDARY WILL
TIGHTEN OVER THE NORTHERN PORTION OF THE LAKE...ALLOWING
NORTH/NORTHEAST WINDS TO INCREASE TO 15 TO 25 KT WITH OCCASIONAL
GUSTS TO 30 KT. THE NORTH WINDS WILL EVENTUALLY REACH THE SOUTHERN
PORTION OF LAKE MICHIGAN...ALLOWING FOR A LONG FETCH TO SETUP.
THIS POINTS TOWARDS BUILDING WAVES FOR THE SOUTHERN TIP OF THE
LAKE...INCLUDING BOTH THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS. HAVE HOISTED A SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
HAZARDOUS WINDS/WAVES OVERNIGHT...ACROSS ILLINOIS NEARSHORE ZONES
FIRST...THEN REACHING NORTHWEST INDIANA NEARSHORE WATERS FRIDAY
MORNING.
WAVES WILL REMAIN HAZARDOUS THROUGH MUCH OF THE DAY
FRIDAY...DESPITE SLOWLY DIMINISHING WINDS AS A WEAK AREA OF HIGH
PRESSURE BUILDS OVER THE LAKE FRIDAY EVENING THROUGH EARLY
SATURDAY. THEN ANOTHER STRONG COLD FRONT WILL SLIDE EAST ACROSS
THE UPPER MIDWEST EARLY SATURDAY...REACHING LAKE MICHIGAN BY
MIDDAY. THIS WILL BRING ANOTHER TIGHT GRADIENT AND A RETURN TO
GUSTY NORTHWEST WINDS. AT THIS TIME GUSTS SHOULD BE AROUND 30
KT...HOWEVER A FEW GALE FORCE GUSTS MAY OCCUR.
LIGHT AND VARIABLE WINDS SET UP AGAIN FOR LATE SUNDAY INTO
MONDAY...AS ANOTHER AREA OF HIGH PRESSURE BUILDS ACROSS THE
WESTERN LAKES. THIS HIGH SHIFTS EAST MONDAY NIGHT...WITH YET
ANOTHER SHARP PRESSURE GRADIENT DEVELOPING ACROSS THE WESTERN
LAKES TUESDAY WITH A POTENT STORM SYSTEM SLIDING EAST ACROSS
ONTARIO TUESDAY. THIS WILL ALLOW STRONG SOUTHERLY WINDS AHEAD OF
THE FRONTAL BOUNDARY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
625 PM CDT THU MAY 9 2013
.MESOSCALE DISCUSSION...
620 PM CDT
CONTINUING TO WATCH CONVECTIVE TRENDS THROUGH THE EVENING HOURS AS
BANDS OF RAIN CURRENTLY LIFT ACROSS THE CWA THANKS TO MOIST WARM
ADVECTION. SATELLITE IMAGERY SHOWS A SLIVER OF CLEARING THAT
DEVELOPED RIGHT ALONG THE MISSISSIPPI RIVER FROM THE QUAD CITIES
ON SOUTH IN CONJUNCTION WITH A SURFACE TROUGH/COOL FRONT WITH A
MORE SIZABLE AREA OF CLEARING FROM MACOMB SOUTH TO THE ST. LOUIS
AREA. A NARROW LINE OF STORMS HAS FIRED AND IS JUST EAST OF THE
RIVER FROM THE QUAD CITIES SOUTH AT 23Z. 23Z SFC OBS SHOW THE
CENTER OF THE SFC LOW NEAR MUSCATINE WITH PRESSURE FALLS FOCUSED
NEAR DECATUR BUT STEADILY SPREADING NORTHWARD ACROSS THE I-80
CORRIDOR. NEAR TERM GUIDANCE IS HAVING A TOUGH TIME AGREEING ON
THE PATH OF THE LOW WITH THE RAP BEING THE FURTHER NORTH OUTLIER
AMONG HIGH RES GUIDANCE. THERE IS SOME SUPPORT FOR AT LEAST A
SLIGHTLY FURTHER NORTH TRACK...GIVEN THE PRESSURE FALLS DEVELOPING
NORTH AND SOUTH WINDS CURRENTLY IN PLACE ACROSS THE ENTIRE CWA
MINUS THE EXTREME NE CORNER. A FURTHER SOUTH TRACK WOULD QUICKLY
ALLOW WINDS TO TURN EAST AND NORTHEAST ACROSS MOST OF THE AREA
THIS EVENING WOULD SUPPORT A MINIMAL THUNDER THREAT...WITH THE
FURTHER NORTH TRACK MORE SUPPORTIVE OF A STILL LOW BUT SLIGHTLY
INCREASED STRONG TS THREAT. WITH ALL OF THIS IN MIND EXPECT THAT
THE NARROW LINE OF STORMS WILL CONTINUE EASTWARD WITH THE
INSTABILITY AXIS SPREADING A BIT MORE NORTH AND EAST OVER THE NEXT
1-2 HOURS HELPING TO KEEP THE LINE GOING. WITH SUNSET APPROACHING
HAVE A HARD TIME SEEING ANY KIND OF INCREASE OR EVEN MAINTENANCE
OF STRONGER CONVECTION ESPECIALLY GIVEN THAT IT WILL BE MOVING
FURTHER INTO THE CWA WHERE THINGS ARE ALREADY QUITE
STABLE...BUT AREAS NEAR THE WESTERN CWA BORDER FROM ABOUT LA
SALLE TO WEST OF PONTIAC STAND A CHANCE OF SEEING THIS ACTIVITY A
COUPLE HOURS FROM NOW. HEAVY RAIN LOOKS TO BE THE MAIN THREAT
OVERALL WITH THE MOIST ATMOSPHERE AND LOW LEVEL...BUT SOME SMALL
HAIL OR SOME STRONGER WINDS COULD OCCUR BUT SEEM UNLIKELY OVERALL.
DEEP LAYER SHEAR IS ONLY AROUND 30 KT OR SO BASED ON THE SPC
MESOANLYSIS BUT HAVE SEEN SOME WEAK LOW LEVEL CIRCULATIONS ON THE
KDVN RADAR DUE TO STRONG LOW LEVEL CAPE AND LOW LEVEL VORTICITY
ALONG THE BOUNDARY SO WILL NEED TO KEEP AN EYE ON THIS AS IT MOVES
EAST. OUTSIDE OF THE TS POTENTIAL...WINDS WILL BE PROBLEMATIC
GIVEN THE LOW PASSING NEARBY BUT AM THINKING THAT THE PUSH OF
NORTH-NORTHEAST WINDS WILL INCREASE IN SPEED AS THE SUN SETS AND
THE LAKE CAN GAIN INFLUENCE...ULTIMATELY KEEPING THE LOW AT LEAST
SOMEWHAT FURTHER SOUTH THAN WHAT THE RECENT RAP RUNS HAVE
SUGGESTED.
MDB
&&
.DISCUSSION...
322 PM CDT
SHORT TERM...TONIGHT THROUGH SUNDAY
CONCERNS IN THIS PERIOD ARE WITH RAIN AND THUNDER CHANCES
TONIGHT...FOLLOWED BY TEMPERATURES SATURDAY NIGHT AND SUNDAY AS
THERE WILL BE A SIGNIFICANT COOL DOWN.
TONIGHT...WEAK SURFACE LOW WILL TRACK FROM WESTERN ILLINOIS TO
NORTHERN INDIANA AND THEN TO SOUTHWEST LWR MI BY EARLY
FRIDAY...WITH OPEN UPPER WAVE ALSO PUSHING ACROSS REGION. AS THIS
OCCURS... WIDESPREAD SHRA WITH SOME EMBEDDED THUNDER INITIALLY
WILL LIFT NORTHEAST WITH CONVECTIVE ACTIVITY DIMINISHING AS
ELEVATED INSTABILITY DIMINISHES WITH TIME. PWAT OF 1.3 TO 1.4
INCHES AND GOOD MOISTURE TRANSPORT AND CONVERGENCE WILL SUPPORT
EFFICIENT RAINFALL PRODUCTION AND THUS CANT RULE OUT MODERATE TO
OCCASIONALLY HEAVY RAIN RATES UNTIL THE LATE EVENING. AS LOW
TRACKS ACROSS AREA...QUASI STATIONARY FRONT THAT HAS BEEN LAID OUT
ACROSS AREA THIS AFTERNOON WILL PUSH SOUTH AS A COLD FRONT THROUGH
ALL BUT SOUTHEASTERN CWA...WITH COOLER AIR MASS/IN THE 40S TO
LOWER 50S FILTERING IN BY EARLY FRIDAY.
MOST SHRA ACTIVITY SHOULD BE ISOLATED AT BEST ON FRIDAY...EXCEPT FOR
PERHAPS MORE SCATTERED SHRA AHEAD OF FRONT AS IT FINALLY CLEARS OUR
FAR SOUTHEAST BY EARLY AFTERNOON. MILDER START IN THIS AREA COULD
ALLOW HIGHS TO REACH MID TO UPPER 60S...WITH REST OF AREA AWAY FROM
LAKE GENERALLY IN THE LOWER 60S. BIG STORY FRIDAY WILL BE THE STRONG
PUSH OF NORTHERLY WINDS DOWN THE LENGTH OF LAKE MICHIGAN BRINGING
QUITE A CHILLY DAY...WITH HIGHS ONLY AROUND 50 AND WINDS GUSTING AS
HIGH AS 30 MPH.
FRIDAY NIGHT WILL BE DRY AND COOL WITH LOWS IN THE 40S...BUT
AN UNSEASONABLY DEEP UPPER TROUGH WILL PUSH INTO THE UPPER GREAT
LAKES REGION BY SATURDAY...WITH A STRONG COLD FRONT TRAILING FROM
SURFACE LOW PRESSURE. THIS FRONT SHOULD TOUCH OFF A FEW SCT SHRA AS
IT PUSHES THROUGH THE CWA ON SATURDAY DUE TO STEEPENING LOW LEVEL
LAPSE RATES...BUT THE MAIN FOCUS WILL BE THE 850 MB TEMPS COOLING TO
-3C TO -4C BY EARLY SUNDAY...LEAVING A COOL BUT MOSTLY SUNNY MOTHERS
DAY. SOME CONCERN WITH FROST POTENTIAL AS EARLY AS SATURDAY
NIGHT...BUT HIGH PRESSURE SHOULD BE FAR ENOUGH WEST TO MAINTAIN A
GRADIENT AND PRECLUDE FROST FORMATION. ACTUALLY A BIGGER CONCERN
SATURDAY NIGHT IS THAT WHETHER THERE IS FROST OR NOT...AIR TEMPS IN
OUTLYING AREAS COULD DIP TO OR BELOW FREEZING IN UNSEASONABLY COOL
AND DRY AIR MASS IN PLACE. IF THE SUB FREEZING TEMPS REALIZED ON
SOME GUIDANCE IS REALIZED...MAY NEED A FREEZE WATCH FOR PORTIONS OF
AREA SATURDAY NIGHT...AS WE ARE QUICKLY TRENDING TO FULL VEGETATION.
DESPITE FULL SUNSHINE ON MOTHERS DAY...CLIMO WITH 850 TEMPS SUBZERO
C ONLY SUPPORTS HIGHS IN THE MID TO UPPER 50S.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...
CONCERNS IN THE LONG TERM WILL RAPIDLY SHIFT FROM COLD WEATHER
CONCERNS INITIALLY TO VERY WARM TEMPERATURES ON TUESDAY. HIGH
PRESSURE RIDGE AXIS WILL BE OVER THE REGION SUNDAY NIGHT YIELDING
MUCH LIGHTER WINDS. COUPLED WITH CLEAR SKIES AND DRY AIR MASS...WITH
DEW POINTS ONLY AROUND 30...STAGE COULD BE SET FOR LOWS NEAR FREEZING
IN SOME AREAS EARLY MONDAY AND ALSO FROST POTENTIAL. AGAIN LOWERED
TEMPS FROM BLEND OF PREVIOUS FCST AND CONSENSUS GUIDANCE TO
GENERALLY MID 30S EXCEPT RIGHT IN THE CHICAGO HEAT ISLAND...WITH
NEAR FREEZING TEMPS IN TYPICALLY COLDER RURAL AND SUBURBAN LOCATIONS
WEST OF THE FOX RIVER. WILL ADD PATCHY FROST TO THE GRIDS FOR AREAS
AWAY FROM CHICAGO.
THEN EARLY NEXT WEEK...UPPER LEVEL RIDGE QUICKLY AMPLIFIES OVER THE
AREA...WITH RAPIDLY WARMING TEMPS ALOFT. ON MONDAY...HIGHS WILL WARM
NICELY TO THE MID 60S AFTER THE CHILLY START. THEN TUES...850 TEMPS
SOAR TO 18+ TO +20C OR HIGHER (NEW ECMWF HAS +23C! OVER NORTH
CENTRAL IL BY 00Z WEDS) IN GUSTY SOUTHWESTERLY BDRY LAYER FLOW. 850
MB CLIMO WOULD SUGGEST MID 80S AT A MINIMUM IN MID MAY WITH
THESE TEMPS ALOFT. FCST SOUNDINGS SUGGEST HOW DEEP WE MIX COULD
BE A LIMITING FACTOR/IE. TO AROUND 900 MB ON THE GFS AND ECMWF.
AGAIN BUMPED TEMPERATURES UP FROM PREVIOUS FCST AND CONSENSUS BLEND
TO LOW TO MID 80S AND EVEN THIS COULD BE CONSERVATIVE WITH SUCH A
WARM AIR MASS IN PLACE ASSUMING THERE ARE NO LINGERING ISSUES WITH
WAA CLOUD COVER. EXTENDED GUIDANCE CONSISTENT IN FEATURING COLD
FRONT SLIPPING SOUTH INTO PORTION OF AREA ON WEDNESDAY...THOUGH
IT APPEARS IT WILL BE ANOTHER WARM DAY WITH HIGHS AT LEAST INTO
THE UPPER 70S TO AROUND 80. THERE ARE SOME DIFFERENCES ON
SHRA/TSRA CHANCES WITH THIS FRONT...AS NORTHERN CWA COULD BE
FAVORED WEDS AFTERNOON WITH BETTER CHANCES BY WEDNESDAY NIGHT.
GUIDANCE THEN DIVERGES ON HOW FAST FRONT PUSHES THROUGH AREA...AS
IT COULD STALL OUT THURSDAY AND EVEN INTO FRIDAY...KEEPING SHRA
AND TSRA CHANCES GOING.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* -RA/-SHRA THIS EVEN INTO OVERNIGHT.
* S TO SW SFC WINDS SHIFTING NE LATE EVE AND N OVERNIGHT.
* INCREASING COVERAGE OF MVFR CIGS AND/OR VSBYS THIS
EVE...DETERIORATING TO IFR CIGS DURING LATE EVE AND PERSISTING
INTO OVERNIGHT...THEN IMPROVING TO MVFR BY MID FRI MORNING.
TRS
//DISCUSSION...UPDATED 18Z...
LINE OF SHRA/TSRA LIFTING NORTH ACROSS CENTRAL IL HAS BEGUN TO
WEAKEN AS ADDITIONAL TSRA LIFT NORTHEAST ACROSS EASTERN IL. WHILE
THIS ACTIVITY IS WEAKENING...HAVE ADJUSTED TIMING...A LITTLE
EARLIER...AS SOME SHOWER ACTIVITY WILL LIKELY REACH THE TERMINALS
BY MID AFTERNOON. ADDITIONAL SHOWERS AND PERHAPS ISOLATED TSRA
WILL CONTINUE TO DEVELOP/SPREAD NORTH ACROSS THE AREA THROUGH
EARLY THIS EVENING AS AN UPPER WAVE LIFTS NORTH. APPEARS THE BEST
THUNDER COVERAGE WILL REMAIN SOUTHEAST OF THE TERMINALS AND FOR
NOW HAVE MAINTAINED VCTS BUT TRENDS WILL NEED TO BE MONITORED FOR
UPDATES. AS AN AREA OF SURFACE LOW PRESSURE MOVES ACROSS THE AREA
LATE TONIGHT INTO THE EARLY OVERNIGHT HOURS...ADDITIONAL SHOWERS
WILL BE POSSIBLE.
THIS SURFACE LOW...AND THE LOCATION OF THE WARM FRONT AHEAD OF IT
THIS AFTERNOON WILL MAKE WIND DIRECTIONS PROBLEMATIC. SOUTHERLY
WINDS TO THE I-80 CORRIDOR LOOK ON TRACK BUT AT MDW/ORD...WINDS ON
ONE MINUTE DATA HAVE BEEN LIGHT WESTERLY TO LIGHT EASTERLY...AS
WELL AS CALM. WHILE GRADIENT REMAINS WEAK...APPEARS AS THE SURFACE
LOW APPROACHES...SOUTHEASTERLY WINDS WILL LIKELY PREVAIL AND THEN
SHIFT MORE EAST THEN NORTHEAST THIS EVENING BUT CONFIDENCE
REGARDING WINDS THROUGH THIS EVENING REMAINS LOW.
CIGS WILL LIKELY BEGIN TO FALL INTO MVFR AS PRECIP DEVELOPS AND AS
THE LOW LEVELS SATURATE WITH FLOW OFF THE LAKE...EXPECT CIGS TO
QUICKLY LOWER INTO IFR THIS EVENING AND AS THE SURFACE LOW
APPROACHES...CIGS LIKELY TO DROP INTO LIFR AND POSSIBLY VLIFR WITH
CIGS SLOWLY LIFTING FRIDAY MORNING AS THE LOW SHIFTS EAST. CMS
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM CONFIDENCE IN FORECAST ELEMENTS INTO LATE EVENING.
* LOW CONFIDENCE IN FORECAST CIGS AND/OR VSBYS LATE EVENING INTO
OVERNIGHT....WITH MEDIUM CONFIDENCE IN OTHER ELEMENTS.
* MEDIUM CONFIDENCE IN ALL FOR CAST ELEMENTS FRI MORNING INTO
AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...CLEARING SKIES.
SATURDAY...VFR. GUSTY NORTHWEST WINDS.
SUNDAY AND MONDAY...VFR.
TUESDAY...STRONG SOUTHERLY WINDS...OTHERWISE VFR.
WEDNESDAY...CHANCE OF TSRA.
KJB
&&
.MARINE...
236 PM CDT
A SLOW MOVING COLD FRONT CONTINUES TO SAG SOUTH ACROSS LAKE
MICHIGAN THIS AFTERNOON. AN AREA OF LOW PRESSURE CENTERED NEAR
SOUTHEAST IOWA THIS AFTERNOON WILL LIFT NORTHEAST ALONG THIS
FRONTAL BOUNDARY...INTO NORTHERN ILLINOIS. THEN THE LOW PRESSURE
WILL CONTINUE TO SLIDE EAST ACROSS NORTHERN ILLINOIS FRIDAY
MORNING. MEANWHILE...THE GRADIENT BEHIND THE FRONTAL BOUNDARY WILL
TIGHTEN OVER THE NORTHERN PORTION OF THE LAKE...ALLOWING
NORTH/NORTHEAST WINDS TO INCREASE TO 15 TO 25 KT WITH OCCASIONAL
GUSTS TO 30 KT. THE NORTH WINDS WILL EVENTUALLY REACH THE SOUTHERN
PORTION OF LAKE MICHIGAN...ALLOWING FOR A LONG FETCH TO SETUP.
THIS POINTS TOWARDS BUILDING WAVES FOR THE SOUTHERN TIP OF THE
LAKE...INCLUDING BOTH THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE
WATERS. HAVE HOISTED A SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
HAZARDOUS WINDS/WAVES OVERNIGHT...ACROSS ILLINOIS NEARSHORE ZONES
FIRST...THEN REACHING NORTHWEST INDIANA NEARSHORE WATERS FRIDAY
MORNING.
WAVES WILL REMAIN HAZARDOUS THROUGH MUCH OF THE DAY
FRIDAY...DESPITE SLOWLY DIMINISHING WINDS AS A WEAK AREA OF HIGH
PRESSURE BUILDS OVER THE LAKE FRIDAY EVENING THROUGH EARLY
SATURDAY. THEN ANOTHER STRONG COLD FRONT WILL SLIDE EAST ACROSS
THE UPPER MIDWEST EARLY SATURDAY...REACHING LAKE MICHIGAN BY
MIDDAY. THIS WILL BRING ANOTHER TIGHT GRADIENT AND A RETURN TO
GUSTY NORTHWEST WINDS. AT THIS TIME GUSTS SHOULD BE AROUND 30
KT...HOWEVER A FEW GALE FORCE GUSTS MAY OCCUR.
LIGHT AND VARIABLE WINDS SET UP AGAIN FOR LATE SUNDAY INTO
MONDAY...AS ANOTHER AREA OF HIGH PRESSURE BUILDS ACROSS THE
WESTERN LAKES. THIS HIGH SHIFTS EAST MONDAY NIGHT...WITH YET
ANOTHER SHARP PRESSURE GRADIENT DEVELOPING ACROSS THE WESTERN
LAKES TUESDAY WITH A POTENT STORM SYSTEM SLIDING EAST ACROSS
ONTARIO TUESDAY. THIS WILL ALLOW STRONG SOUTHERLY WINDS AHEAD OF
THE FRONTAL BOUNDARY.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...1 AM FRIDAY TO 4
AM SATURDAY.
SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...7 AM FRIDAY TO 4
AM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
944 PM EDT THU MAY 9 2013
.SYNOPSIS...
ISSUED AT 942 PM EDT THU MAY 9 2013
AN AREA OF LOW PRESSURE AND A COLD FRONT WILL MOVE THROUGH THE
REGION INTO FRIDAY NIGHT BRINGING WITH IT SHOWERS AND ISOLATED
THUNDERSTORMS. A SECONDARY COLD FRONT WILL BRING A LOW CHANCE FOR
SHOWERS ON SATURDAY WITH MUCH COLDER AIR BEHIND IT. HIGH PRESSURE
WILL THEN PROVIDE DRY CONDITIONS INTO EARLY NEXT WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 335 PM EDT THU MAY 9 2013
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO OVERSPREAD THE REGION
THIS EVENING AHEAD OF AN AREA OF LOW PRESSURE. AN UPPER VORT MAX IS
ALSO AIDING IN THUNDERSTORM DEVELOPMENT. 850 MB WINDS NEAR 40KT
ACROSS THE SOUTHERN FORECAST AREA WILL BRING IN MOISTURE AS WELL.
THUS WENT LIKELY TO CATEGORICAL POPS THIS EVENING INTO EARLY
OVERNIGHT. THEN GRADUALLY LOWERED POPS AS UPPER SUPPORT DIMINISHES
AND FIRST AREA OF LOW PRESSURE MOVES OUT.
ANOTHER AREA OF LOW PRESSURE WILL DEVELOP ALONG THE COLD FRONT AND
MOVE ALONG IT ON FRIDAY. STRONGEST 850 MB WINDS WILL BE FOCUSING
ON AREAS SOUTH AND EAST OF THE FORECAST AREA. WITH THE FRONT
MOVING THROUGH THE FORECAST AREA DURING THE DAY AND BEST FORCING
MOVING EAST...WENT LIKELY POPS ACROSS THE EAST THIRD WITH CHANCE
POPS ELSEWHERE. GRADUALLY DECREASED POPS DURING THE AFTERNOON AS
THE SYSTEM MOVES EAST.
LOOKING AT TEMPERATURES...TRENDED TOWARD THE WARMER SIDE OF MOS
TONIGHT WITH THE AREA STILL AHEAD OF THE COLD FRONT. FOR FRIDAY
WENT CLOSER TO THE WARMER MAV MOS AS THE FRONT WILL TAKE A WHILE
TO MOVE THROUGH /AS LOW PRESSURE RIDES ALONG IT/.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM EDT THU MAY 9 2013
FOCUS WILL BE ON CHANCES FOR RAIN THROUGH THE PERIOD. GENERALLY
STUCK WITH A MODEL BLEND THROUGH THE PERIOD SINCE UNCERTAINTY
INCREASES LATER IN THE PERIOD. DETAILS BELOW.
KEPT LOW POPS ACROSS THE EASTERN FORECAST AREA FRIDAY NIGHT AS THE
SYSTEM SLOWLY EXITS THE AREA. WENT WITH A MODEL BLEND FOR
TEMPERATURES.
ANOTHER COLD FRONT WILL MOVE INTO THE AREA SATURDAY AFTERNOON.
THERE SHOULDN/T BE MUCH MOISTURE AVAILABLE FOR THIS FRONT...AND
CONVERGENCE ALONG THE FRONT IS WEAK. HOWEVER THERE IS A DECENT
AIRMASS CHANGE BEHIND THE FRONT...SO THERE STILL MAY BE ENOUGH
FORCING TO GENERATE SOME SCATTERED SHOWERS. WENT CHANCE POPS MOST
AREAS SATURDAY AFTERNOON.
HIGH PRESSURE WILL BUILD INTO THE AREA FOR SATURDAY NIGHT INTO
TUESDAY. THIS WILL KEEP DRY CONDITIONS THROUGH THIS TIME FRAME.
TEMPERATURES WILL START OUT QUITE COOL...WITH TEMPERATURES NEAR
FREEZING ACROSS NORTHEAST AREAS BY SUNDAY NIGHT. THIS WILL LEAD
TO A COOL DAY ON MONDAY...BUT THEN RETURN FLOW AROUND THE HIGH
WILL LEAD TO NEAR NORMAL READINGS ON TUESDAY.
AS UPPER FLOW BECOMES MORE ZONAL WEDNESDAY AND THURSDAY...TIMING OF
WAVES IN THE FLOW BECOMES IN QUESTION. THUS UNCERTAINTY IS HIGHER IN
TIMING AND LOCATION OF AN APPROACHING COLD FRONT AND ASSOCIATED
RAINFALL. THUS WENT CHANCE POPS WEDNESDAY INTO THURSDAY ACROSS THE
AREA...NOT TOO DIFFERENT FROM THE ALLBLEND INITIALIZATION.
WARM TEMPERATURES WILL CONTINUE WEDNESDAY BUT READINGS WILL FALL
SOME ON THURSDAY WITH COLD FRONT AND RAINFALL IN THE VICINITY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY)
ISSUED AT 726 PM EDT THU MAY 9 2013
GENERAL VFR CONDS THIS EVENING XPCD TO DETERIORATE TO WIDESPREAD
MVFR OVERNIGHT IN RESPONSE TO CONTD LL MSTR FLUX AND EVENTUAL NEWD
EXPANSION OF MORE WIDESPREAD SHRA DVLPG ON NOSE OF LLJ EWD OF
UPSTREAM SW LIFTING OUT OF WRN IL. HWVR RUC SCENARIO OF SUSTAINED
BNDRY LYR MSTR ADVTN AHD OF SLOWING EWD EJECTING SFC CYCLONE WOULD
POINT TO A LIKELY PD OF IFR CIGS TWD DAYBREAK AND INCLUDED W/00Z
ISSUANCE. OTRWS DROPPED PRIOR TSRA MENTION IN LIGHT OF MARGINAL
THETA-E RIDGING DVLPG THIS FAR N AS STGR LLJ INDUCED ASCENT SLIDES
THROUGH CNTRL IN OVERNIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...NG
SHORT TERM...50
LONG TERM...50
AVIATION...T
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
726 PM EDT THU MAY 9 2013
.SYNOPSIS...
ISSUED AT 335 PM EDT THU MAY 9 2013
AN AREA OF LOW PRESSURE AND A COLD FRONT WILL MOVE THROUGH THE
REGION INTO FRIDAY NIGHT BRINGING WITH IT SHOWERS AND
THUNDERSTORMS. A SECONDARY COLD FRONT WILL BRING A LOW CHANCE FOR
SHOWERS ON SATURDAY WITH MUCH COLDER AIR BEHIND IT. HIGH PRESSURE
WILL THEN PROVIDE DRY CONDITIONS INTO EARLY NEXT WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 335 PM EDT THU MAY 9 2013
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO OVERSPREAD THE REGION
THIS EVENING AHEAD OF AN AREA OF LOW PRESSURE. AN UPPER VORT MAX IS
ALSO AIDING IN THUNDERSTORM DEVELOPMENT. 850 MB WINDS NEAR 40KT
ACROSS THE SOUTHERN FORECAST AREA WILL BRING IN MOISTURE AS WELL.
THUS WENT LIKELY TO CATEGORICAL POPS THIS EVENING INTO EARLY
OVERNIGHT. THEN GRADUALLY LOWERED POPS AS UPPER SUPPORT DIMINISHES
AND FIRST AREA OF LOW PRESSURE MOVES OUT.
ANOTHER AREA OF LOW PRESSURE WILL DEVELOP ALONG THE COLD FRONT AND
MOVE ALONG IT ON FRIDAY. STRONGEST 850 MB WINDS WILL BE FOCUSING
ON AREAS SOUTH AND EAST OF THE FORECAST AREA. WITH THE FRONT
MOVING THROUGH THE FORECAST AREA DURING THE DAY AND BEST FORCING
MOVING EAST...WENT LIKELY POPS ACROSS THE EAST THIRD WITH CHANCE
POPS ELSEWHERE. GRADUALLY DECREASED POPS DURING THE AFTERNOON AS
THE SYSTEM MOVES EAST.
LOOKING AT TEMPERATURES...TRENDED TOWARD THE WARMER SIDE OF MOS
TONIGHT WITH THE AREA STILL AHEAD OF THE COLD FRONT. FOR FRIDAY
WENT CLOSER TO THE WARMER MAV MOS AS THE FRONT WILL TAKE A WHILE
TO MOVE THROUGH /AS LOW PRESSURE RIDES ALONG IT/.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM EDT THU MAY 9 2013
FOCUS WILL BE ON CHANCES FOR RAIN THROUGH THE PERIOD. GENERALLY
STUCK WITH A MODEL BLEND THROUGH THE PERIOD SINCE UNCERTAINTY
INCREASES LATER IN THE PERIOD. DETAILS BELOW.
KEPT LOW POPS ACROSS THE EASTERN FORECAST AREA FRIDAY NIGHT AS THE
SYSTEM SLOWLY EXITS THE AREA. WENT WITH A MODEL BLEND FOR
TEMPERATURES.
ANOTHER COLD FRONT WILL MOVE INTO THE AREA SATURDAY AFTERNOON.
THERE SHOULDN/T BE MUCH MOISTURE AVAILABLE FOR THIS FRONT...AND
CONVERGENCE ALONG THE FRONT IS WEAK. HOWEVER THERE IS A DECENT
AIRMASS CHANGE BEHIND THE FRONT...SO THERE STILL MAY BE ENOUGH
FORCING TO GENERATE SOME SCATTERED SHOWERS. WENT CHANCE POPS MOST
AREAS SATURDAY AFTERNOON.
HIGH PRESSURE WILL BUILD INTO THE AREA FOR SATURDAY NIGHT INTO
TUESDAY. THIS WILL KEEP DRY CONDITIONS THROUGH THIS TIME FRAME.
TEMPERATURES WILL START OUT QUITE COOL...WITH TEMPERATURES NEAR
FREEZING ACROSS NORTHEAST AREAS BY SUNDAY NIGHT. THIS WILL LEAD
TO A COOL DAY ON MONDAY...BUT THEN RETURN FLOW AROUND THE HIGH
WILL LEAD TO NEAR NORMAL READINGS ON TUESDAY.
AS UPPER FLOW BECOMES MORE ZONAL WEDNESDAY AND THURSDAY...TIMING OF
WAVES IN THE FLOW BECOMES IN QUESTION. THUS UNCERTAINTY IS HIGHER IN
TIMING AND LOCATION OF AN APPROACHING COLD FRONT AND ASSOCIATED
RAINFALL. THUS WENT CHANCE POPS WEDNESDAY INTO THURSDAY ACROSS THE
AREA...NOT TOO DIFFERENT FROM THE ALLBLEND INITIALIZATION.
WARM TEMPERATURES WILL CONTINUE WEDNESDAY BUT READINGS WILL FALL
SOME ON THURSDAY WITH COLD FRONT AND RAINFALL IN THE VICINITY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY)
ISSUED AT 726 PM EDT THU MAY 9 2013
GENERAL VFR CONDS THIS EVENING XPCD TO DETERIORATE TO WIDESPREAD
MVFR OVERNIGHT IN RESPONSE TO CONTD LL MSTR FLUX AND EVENTUAL NEWD
EXPANSION OF MORE WIDESPREAD SHRA DVLPG ON NOSE OF LLJ EWD OF
UPSTREAM SW LIFTING OUT OF WRN IL. HWVR RUC SCENARIO OF SUSTAINED
BNDRY LYR MSTR ADVTN AHD OF SLOWING EWD EJECTING SFC CYCLONE WOULD
POINT TO A LIKELY PD OF IFR CIGS TWD DAYBREAK AND INCLUDED W/00Z
ISSUANCE. OTRWS DROPPED PRIOR TSRA MENTION IN LIGHT OF MARGINAL
THETA-E RIDGING DVLPG THIS FAR N AS STGR LLJ INDUCED ASCENT SLIDES
THROUGH CNTRL IN OVERNIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...50
SHORT TERM...50
LONG TERM...50
AVIATION...T
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
634 PM CDT THU MAY 9 2013
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 221 PM CDT THU MAY 9 2013
AN ELONGATED MID LEVEL VORTICITY AXIS WAS FOUND ACROSS THE CENTRAL
PLAINS TODAY COMPLETE WITH MOISTURE AND FAIRLY COOL TEMPERATURES.
UPPER AIR OBSERVATIONS AND RAP ANALYSIS INDICATED 500/700MB
TEMPERATURES AROUND -17C/0C RESPECTIVELY. SOME INSOLATION THROUGH
EARLY AFTERNOON RESULTED IN SURFACE TEMPERATURES WARMING INTO THE
UPPER 60S TO NEAR 70 DEGREES PARTICULARLY SOUTH OF THE ARKANSAS
RIVER. THE MID LEVEL MOISTURE AXIS WAS FOUND TO BE CENTERED FROM THE
CENTRAL ROCKIES THROUGH NORTHERN KANSAS AND MUCH OF NEBRASKA. THIS
LINED UP FAIRLY WELL WITH THE MEAN 500-700MB DEFORMATION AXIS. THE
SURFACE FRONT HAD PUSHED WELL SOUTH OF THE REGION DOWN INTO SOUTHERN
OKLAHOMA, SO SURFACE-BASED INSTABILITY WAS VERY LOW ACROSS
SOUTHWESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 221 PM CDT THU MAY 9 2013
THE MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES, COVERAGE, AND
INTENSITY THIS EVENING. THE MENTIONED DEFORMATION AXIS WILL LINGER
ACROSS SOUTHEASTERN COLORADO AND WESTERN KANSAS THROUGH THIS
EVENING. THE UPDATED FORECAST POP/WX GRIDS WILL REFLECT THE HRRR
MODEL THINKING OF WEAK UPRIGHT CONVECTION FORMING NEAR A VORTICITY
CENTER ACROSS SOUTHEASTERN COLORADO. A LOOSELY ORGANIZED CLUSTER OF
CONVECTION COULD DEVELOP A COLD POOL ALLOWING THE CLUSTER OF
CONVECTION TO MOVE INTO THE SOUTHWESTERN QUARTER OR THIRD OF THE DDC
FORECAST AREA (SOUTH AND WEST OF A LAKIN TO MEADE LINE, ROUGHLY).
THE ABSENCE OF APPRECIABLE SURFACE-BASED CAPE IS EXPECTED TO KEEP
CONVECTION BELOW SEVERE LIMITS...BUT SOME GUSTS TO 50 OR 55 MPH WILL
BE POSSIBLE IF LOOSELY ORGANIZED COLD POOLS DEVELOP. ANY STORMS
WHICH IMPACT FAR SOUTHWESTERN KANSAS SHOULD BE EXITING THE AREA BY
LATE EVENING.
ON FRIDAY...WESTERN KANSAS WILL BE UNDER AN INCREASED INFLUENCE OF
NORTHWEST FLOW ALOFT AS THE MID LEVEL SHEAR AXIS CONTINUES TO PUSH
SOUTH INTO TEXAS. THIS IS EXPECTED TO RESULT IN MORE TRANQUIL
SENSIBLE WEATHER. THAT BEING SAID...MID LEVEL TEMPERATURES WILL
STILL BE COOL (700MB TEMPERATURE -2 TO 0C)...AND MIXING
CONDENSATION LEVELS WILL BE LOW AS INSOLATION ALLOWS SURFACE TEMPS
TO WARM INTO THE UPPER 60S. THE RESULT WILL BE DEVELOPMENT OF
CUMULUS AND PERHAPS AN ISOLATED SHOWER OR TO LATE IN THE DAY. THE
OFFICIAL FORECAST WILL BE DRY AS THERE WILL BE AN ABSENCE OF UPPER
LEVEL FORCING FOR ASCENT TO PROMOTE ANY ORGANIZATION OF
CONVECTION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CDT THU MAY 9 2013
THE WEATHER PICTURE THIS WEEKEND WILL DEPICT AN UPPER LEVEL LONG
WAVE TROUGH DIGGING ACROSS THE NORTHEAST UNITED STATES AND AN UPPER
LEVEL RIDGE BUILDING ACROSS THE WESTERN UNITED STATES. MEANWHILE,
THE UPPER LEVEL LOW THAT ASSISTED IN SEVERE STORM DEVELOPMENT ACROSS
OUR AREA THE LAST COUPLE OF NIGHTS WILL SPLIT OFF FROM THE FLOW AND
MIGRATE TOWARDS NORTHERN MEXICO. THESE FEATURES WILL PLACE THE
CENTRAL HIGH PLAINS UNDER NORTHWEST FLOW ALOFT. THIS PATTERN USUALLY
GIVES WAY TO FAIR WEATHER DAYS ACROSS WESTERN KANSAS. HOWEVER, RAIN
CHANCES WILL BE POSSIBLE SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE
AT THE SURFACE WILL BE THE DOMINATE FEATURE ACROSS WESTERN KANSAS
FRIDAY NIGHT INTO SATURDAY WITH A SECOND AREA OF HIGH PRESSURE
OOZING DOWN FROM THE NORTH SATURDAY NIGHT INTO SUNDAY. A COLD FRONT
WILL BE FOUND IN BETWEEN THESE TWO AREAS OF HIGH PRESSURE ALLOWING
SOME LIFT TO OCCUR ACROSS THE PLAINS SATURDAY NIGHT. THE ATMOSPHERE
WILL BE FAIRLY DRY AS THIS FRONT MOVES THROUGH BUT THERE COULD BE A
SHOWER OR TWO THAT FORMS SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
WINDS WILL GENERALLY BE LIGHT AND VARIABLE FRIDAY NIGHT INTO
SATURDAY SHIFTING TO THE NORTH BEHIND THE FRONT SATURDAY NIGHT INTO
SUNDAY. A WEAK UPPER LEVEL SHORTWAVE IS THEN DEPICTED BY THE MODELS
TO MOVE DOWN THROUGH THE NORTHWEST FLOW AND INTO KANSAS SUNDAY. IF
THIS COMES TO FRUITION, THUNDERSTORM WILL BE POSSIBLE ACROSS CENTRAL
KANSAS SUNDAY MORNING SPREADING TOWARDS SOUTH CENTRAL KANSAS AS THE
DAY PROGRESSES. OTHERWISE PARTLY CLOUDY SKIES WILL BE FOUND ACROSS
WESTERN KANSAS. LEE TROUGHING WILL ALSO BE DEVELOPING ACROSS THE
KS/CO BORDER DURING THIS TIME FRAME SHIFTING WINDS TO MORE OF A
SOUTHERLY DIRECTION. LOWS SATURDAY AND SUNDAY MORNING LOOK TO DIP
INTO THE 40S WITH HIGHS IN THE 70S SATURDAY AND SUNDAY AFTERNOON.
THE UPPER LEVEL RIDGE ACROSS THE WESTERN UNITED STATES WILL THEN
SHIFT EASTWARD INTO THE ROCKIES AND PLAINS DURING THE FIRST PART OF
NEXT WEEK. THIS FEATURE IN CONJUNCTION WITH SURFACE HIGH PRESSURE
LOCATED EAST OF KANSAS WILL BRING MOSTLY CLEAR SKIES AND DRY
CONDITIONS TO WESTERN KANSAS. LEE TROUGHING ACROSS EASTERN COLORADO
WILL CONTINUE AND BRING WARM TEMPERATURES TO THE AREA. HIGHS MONDAY
ARE FORECASTED TO REACH INTO THE 80S WITH HIGHS AROUND 90 DEGREES ON
TUESDAY. LOWS WILL GENERALLY BE IN THE 50S MONDAY AND TUESDAY
MORNING.
MID RANGE MODELS THEN SUGGEST THE UPPER LEVEL LOW ACROSS NORTHERN
MEXICO TO MOVE BACK NORTHEAST TO THE SOUTHERN PLAINS. THIS WOULD
BRING INCREASING CHANCES OF THUNDERSTORMS TO PARTS OF KANSAS MID
WEEK INTO THE FIRST PART OF THE WEEKEND. HIGHS DURING THIS TIME
FRAME WILL GENERALLY BE IN THE 80S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 630 PM CDT THU MAY 9 2013
AN ISOLATED THUNDERSTORM IS POSSIBLE THROUGH SUNSET THIS EVENING.
THEN CLOUDS INCREASE WITH A SHORTWAVE TROUGH. VFR CONDITIONS ARE
EXPECTED WITH LIGHT DOWNSLOPE WINDS, HOWEVER SOME OF THE GUIDANCE
IS SHOWING SOME IFR CIGS FOR A FEW HOURS FROM 10-13Z. WITH NORTH
TO NORTHWEST WINDS EXPECTED HAVE NEGATED IFR IN THE TAF.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 47 68 48 71 / 20 10 10 20
GCK 45 68 47 70 / 30 10 10 20
EHA 48 69 47 71 / 30 10 10 20
LBL 48 70 48 73 / 30 10 10 20
HYS 48 69 48 68 / 20 10 20 20
P28 53 71 50 73 / 20 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...HOVORKA_42
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1219 PM CDT WED MAY 8 2013
...AVIATION UPDATE...
.UPDATE...
ISSUED AT 1042 AM CDT WED MAY 8 2013
THE FORECAST REMAINS A BIT TRICKY REGARDING MESOSCALE FEATURES AS
WEAKENING AREA OF PRECIP AND ASSOCIATED WEAK MCV OVER SOUTHEAST
KANSAS HAS INTERFERED WITH THE BROAD SCALE SURFACE PATTERN.
SURFACE LOW PRESSURE REMAINS CENTERED OVER THE OKLAHOMA PANHANDLE
WITH SOME SEMBLANCE OF A SURFACE TROUGH EXTENDING NORTHEAST
THROUGH CENTRAL KANSAS AND INTO EXTREME NORTHEAST KANSAS. THESE
FEATURES ARE NOT EXPECTED TO MOVE MUCH THROUGH THE DAY TODAY.
SOUTHERLY FLOW HAS RESUMED INTO CENTRAL KANSAS IN THE WAKE OF THE
PRECIPITATION BUT SOUTHEASTERLY LOW LEVEL FLOW PERSISTS OVER
SOUTHEAST KANSAS BEHIND A WEAK OUTFLOW BOUNDARY OF SORTS. THIS
COLD POOL AIRMASS IS EXPECTED TO MIX OUT WITH SOUTHERLY FLOW
RESUMING BY EARLY AFTERNOON BUT WEAK REMNANT BOUNDARIES MAY
PROVIDE JUST ENOUGH FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT
BY MID TO LATE AFTERNOON. DRIER MID LEVEL AIR WITH STEEPENING
LAPSE RATES IS ALSO FORECAST TO MOVE NORTHEAST INTO THE FORECAST
AREA BY THIS AFTERNOON AND SHOULD CONTRIBUTE TO SURFACE BASED
INSTABILITY TO AROUND 2000 J/KG WITH MINIMAL INHIBITION. WEAK
CONVERGENCE ALONG THE SURFACE TROUGH AXIS AND ANY WEAK REMNANT
BOUNDARIES WILL LIKELY BE SUFFICIENT TO OVERCOME THE WEAK
INHIBITION LATE THIS AFTERNOON AND THIS EVENING BUT THE EXTENT OF
THUNDERSTORM COVERAGE REMAINS IN QUESTION THROUGH THIS PERIOD.
DEEP LAYER SHEAR PROFILES ARE EXPECTED TO BE RATHER WEAK...PERHAPS
SUPPORTING BRIEF SUPERCELL STRUCTURES BUT MORE LIKELY IN THE
MULTICELL REALM OF CONVECTION. AT THIS TIME...IT APPEARS THAT THE
STRONGEST STORMS MAY BE CAPABLE OF PRODUCING ISOLATED AND
MARGINALLY SEVERE HAIL AND DOWNBURST WINDS.
LATE THIS EVENING AND OVERNIGHT...IT APPEARS THAT CONVECTION OVER
THE HIGH PLAINS WILL MERGE INTO AN MCS OF SORTS WHICH SHOULD RIDE
ALONG THE SURFACE TROUGH AXIS AND NORTH EDGE OF THE INSTABILITY
AXIS ACROSS KANSAS...WITH INCREASING CHANCES FOR THUNDERSTORMS
AFTER MIDNIGHT. STRONG WINDS ARE NOT OUT OF THE QUESTION WITH THIS
ACTIVITY...BUT FEEL THAT THE INSTABILITY WILL BE WANING BY THE
TIME STORMS REACH EASTERN KANSAS AND MAY NO LONGER SUPPORT A
SEVERE WEATHER THREAT.
BARJENBRUCH
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT WED MAY 8 2013
08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A
SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS
THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE
ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED
A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS
EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB.
FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM
THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE
ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND
NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS
AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN
WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED
INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND
POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO
REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER
AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE
HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING
BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE
FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN
KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS.
LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE
HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP
BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND
ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST
AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO
RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND
LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE
REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR
CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR
PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO
WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL
CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND
POSSIBLY SOME DAMAGING WIND GUSTS.
WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS
IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND
THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE
DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3
AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE
SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY
TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS
EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A
GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH.
SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL
KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO
THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON
THE WARM SIDE OF THE TROUGH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 356 AM CDT WED MAY 8 2013
ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE
SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE
POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT
THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND
EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY
SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH
HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER
WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD
LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS
CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE
NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON
FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW
DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY.
A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY
WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE
SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA
WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN
STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER
MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR
ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE
UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD
AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND
UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH
DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON
SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND
UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE
ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN
THE LOW TO MIDDLE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1211 PM CDT WED MAY 8 2013
EXPECT PREDOMINANT VFR CONDITIONS THROUGH THE TAF PERIOD WITH MAIN
UNCERTAINTY BEING THE TIMING OF THUNDERSTORMS AND ANY POTENTIAL
REDUCTION IN FLIGHT CONDITIONS WITH TS. EXPECT TS TO WAIT UNTIL
AFTER 22Z BEFORE SCATTERED STORMS INITIATE...AND MAY WAIT UNTIL
AFTER 00Z. TS CHANCES INCREASE THIS EVENING AND OVERNIGHT WITH
MULTIPLE ROUNDS OF TS POSSIBLY IMPACTING TAF SITES. VIS MAY
BRIEFLY REDUCE TO IFR UNDER HEAVIER STORMS BUT TIMING VERY
UNCERTAIN. BETTER CHANCE OF MORE PERSISTENT MVFR CIGS AS PRECIP
WINDS DOWN AFTER 09Z OR SO...BUT FEEL MORE CONFIDENT IN VFR AT
THIS TIME.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...WOLTERS
LONG TERM...63
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1056 AM CDT WED MAY 8 2013
...UPDATED FORECAST FOR THUNDERSTORM POTENTIAL THROUGH TONIGHT...
.UPDATE...
ISSUED AT 1042 AM CDT WED MAY 8 2013
THE FORECAST REMAINS A BIT TRICKY REGARDING MESOSCALE FEATURES AS
WEAKENING AREA OF PRECIP AND ASSOCIATED WEAK MCV OVER SOUTHEAST
KANSAS HAS INTERFERED WITH THE BROAD SCALE SURFACE PATTERN.
SURFACE LOW PRESSURE REMAINS CENTERED OVER THE OKLAHOMA PANHANDLE
WITH SOME SEMBLANCE OF A SURFACE TROUGH EXTENDING NORTHEAST
THROUGH CENTRAL KANSAS AND INTO EXTREME NORTHEAST KANSAS. THESE
FEATURES ARE NOT EXPECTED TO MOVE MUCH THROUGH THE DAY TODAY.
SOUTHERLY FLOW HAS RESUMED INTO CENTRAL KANSAS IN THE WAKE OF THE
PRECIPITATION BUT SOUTHEASTERLY LOW LEVEL FLOW PERSISTS OVER
SOUTHEAST KANSAS BEHIND A WEAK OUTFLOW BOUNDARY OF SORTS. THIS
COLD POOL AIRMASS IS EXPECTED TO MIX OUT WITH SOUTHERLY FLOW
RESUMING BY EARLY AFTERNOON BUT WEAK REMNANT BOUNDARIES MAY
PROVIDE JUST ENOUGH FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT
BY MID TO LATE AFTERNOON. DRIER MID LEVEL AIR WITH STEEPENING
LAPSE RATES IS ALSO FORECAST TO MOVE NORTHEAST INTO THE FORECAST
AREA BY THIS AFTERNOON AND SHOULD CONTRIBUTE TO SURFACE BASED
INSTABILITY TO AROUND 2000 J/KG WITH MINIMAL INHIBITION. WEAK
CONVERGENCE ALONG THE SURFACE TROUGH AXIS AND ANY WEAK REMNANT
BOUNDARIES WILL LIKELY BE SUFFICIENT TO OVERCOME THE WEAK
INHIBITION LATE THIS AFTERNOON AND THIS EVENING BUT THE EXTENT OF
THUNDERSTORM COVERAGE REMAINS IN QUESTION THROUGH THIS PERIOD.
DEEP LAYER SHEAR PROFILES ARE EXPECTED TO BE RATHER WEAK...PERHAPS
SUPPORTING BRIEF SUPERCELL STRUCTURES BUT MORE LIKELY IN THE
MULTICELL REALM OF CONVECTION. AT THIS TIME...IT APPEARS THAT THE
STRONGEST STORMS MAY BE CAPABLE OF PRODUCING ISOLATED AND
MARGINALLY SEVERE HAIL AND DOWNBURST WINDS.
LATE THIS EVENING AND OVERNIGHT...IT APPEARS THAT CONVECTION OVER
THE HIGH PLAINS WILL MERGE INTO AN MCS OF SORTS WHICH SHOULD RIDE
ALONG THE SURFACE TROUGH AXIS AND NORTH EDGE OF THE INSTABILITY
AXIS ACROSS KANSAS...WITH INCREASING CHANCES FOR THUNDERSTORMS
AFTER MIDNIGHT. STRONG WINDS ARE NOT OUT OF THE QUESTION WITH THIS
ACTIVITY...BUT FEEL THAT THE INSTABILITY WILL BE WANING BY THE
TIME STORMS REACH EASTERN KANSAS AND MAY NO LONGER SUPPORT A
SEVERE WEATHER THREAT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT WED MAY 8 2013
08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A
SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS
THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE
ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED
A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS
EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB.
FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM
THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE
ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND
NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS
AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN
WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED
INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND
POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO
REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER
AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE
HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING
BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE
FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN
KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS.
LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE
HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP
BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND
ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST
AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO
RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND
LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE
REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR
CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR
PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO
WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL
CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND
POSSIBLY SOME DAMAGING WIND GUSTS.
WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS
IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND
THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE
DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3
AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE
SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY
TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS
EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A
GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH.
SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL
KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO
THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON
THE WARM SIDE OF THE TROUGH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 356 AM CDT WED MAY 8 2013
ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE
SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE
POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT
THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND
EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY
SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH
HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER
WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD
LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS
CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE
NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON
FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW
DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY.
A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY
WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE
SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA
WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN
STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER
MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR
ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE
UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD
AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND
UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH
DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON
SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND
UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE
ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN
THE LOW TO MIDDLE 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 635 AM CDT WED MAY 8 2013
TIMING TS WILL BE THE MAIN DIFFICULTY IN THE FORECAST. WITH MODELS
SHOWING LITTLE OR NO INHIBITION DURING PEAK HEATING AND THE SFC
TROUGH AXIS PROGGED TO BE IN THE VICINITY OF THE TERMINALS...THINK
THUNDERSTORMS WILL BE MOVING THROUGH THE TERMINALS BY THE EARLY
EVENING. HAVE KEPT TAFS VFR FOR NOW WITH MODELS SHOWING CIGS ABOVE
3 KFT THROUGH THE DAY...UNTIL TS TIMING BECOMES MORE APPARENT.
THE MAIN RESTRICTION WOULD LIKELY BE REDUCED VSBY FROM MODERATE OR
HEAVY RAINFALL. THERE IS SOME INDICATION OF LOWER CIGS FINALLY
MOVING IN AS THE SURFACE TROUGH AXIS MOVES SOUTH. HOWEVER THIS
LOOKS TO BE AROUND THE END OF THE FORECAST PERIOD...SO WILL LET
LATER SHIFTS DIAGNOSE THIS MORE.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...WOLTERS
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
635 AM CDT WED MAY 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT WED MAY 8 2013
08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A
SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS
THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE
ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED
A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS
EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB.
FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM
THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE
ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND
NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS
AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN
WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED
INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND
POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO
REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER
AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE
HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING
BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE
FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN
KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS.
LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE
HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP
BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND
ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST
AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO
RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND
LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE
REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR
CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR
PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO
WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL
CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND
POSSIBLY SOME DAMAGING WIND GUSTS.
WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS
IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND
THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE
DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3
AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE
SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY
TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS
EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A
GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH.
SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL
KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO
THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON
THE WARM SIDE OF THE TROUGH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 356 AM CDT WED MAY 8 2013
ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE
SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE
POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT
THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND
EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY
SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH
HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER
WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD
LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS
CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE
NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON
FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW
DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY.
A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY
WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE
SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA
WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN
STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER
MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR
ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE
UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD
AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND
UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH
DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON
SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND
UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE
ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN
THE LOW TO MIDDLE 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 635 AM CDT WED MAY 8 2013
TIMING TS WILL BE THE MAIN DIFFICULTY IN THE FORECAST. WITH MODELS
SHOWING LITTLE OR NO INHIBITION DURING PEAK HEATING AND THE SFC
TROUGH AXIS PROGGED TO BE IN THE VICINITY OF THE TERMINALS...THINK
THUNDERSTORMS WILL BE MOVING THROUGH THE TERMINALS BY THE EARLY
EVENING. HAVE KEPT TAFS VFR FOR NOW WITH MODELS SHOWING CIGS ABOVE
3 KFT THROUGH THE DAY...UNTIL TS TIMING BECOMES MORE APPARENT.
THE MAIN RESTRICTION WOULD LIKELY BE REDUCED VSBY FROM MODERATE OR
HEAVY RAINFALL. THERE IS SOME INDICATION OF LOWER CIGS FINALLY
MOVING IN AS THE SURFACE TROUGH AXIS MOVES SOUTH. HOWEVER THIS
LOOKS TO BE AROUND THE END OF THE FORECAST PERIOD...SO WILL LET
LATER SHIFTS DIAGNOSE THIS MORE.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
359 AM CDT WED MAY 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT WED MAY 8 2013
08Z WATER VAPOR SHOWS ONE CLOSED UPPER LOW OVER SOUTHEAST SD WITH A
SECOND JUST WEST OF THE FOUR CORNERS REGION. PROFILER DATA SUGGESTS
THERE IS A WEAK LITTLE MCV OVER CENTRAL KS GENERATED FROM THE
ONGOING CONVECTION IN SOUTH CENTRAL KS. AT THE SURFACE...OBS SHOWED
A MESO HIGH CENTERED OVER NORTHERN LYON COUNTY WHILE A TROUGH AXIS
EXTENDED NORTH FROM THE TX/OK PANHANDLE IN SOUTH CENTRAL NEB.
FOR TODAY THE MAIN QUESTION IS WILL THE BOUNDARY LAYER RECOVER FROM
THE MORNING SHOWERS AND EMBEDDED THUNDERSTORMS. WITH SHORTWAVE
ENERGY POTENTIALLY AFFECTING THE AREA FROM THE SOUTHWEST AND
NORTH...THERE SHOULD SOME SOME BROAD SCALE FORCING FOR ASSENT THIS
AFTERNOON. AND ALL THE MODELS SUGGEST THAT IF THE BOUNDARY LAYER CAN
WARM INTO THE 70S...COOL MID LEVEL TEMPS WOULD YIELD SURFACE BASED
INSTABILITY BETWEEN 2000 AND 2500 J/KG. SO WITH THE FORCING AND
POTENTIAL INSTABILITY...THINK THUNDERSTORMS ARE LIKELY TO
REDEVELOP BY THIS EVENING. THE 00Z NAM APPEARS TO HAVE BEEN OVER
AGGRESSIVE IN CONVECTION THROUGH THE MID MORNING HOURS. AND WITH THE
HRRR AND RAP13 SHOWING PRECIP PUSHING OFF TO THE EAST AND WEAKENING
BY LATE MORNING /WHICH MAKES SINCE GIVEN THE POSSIBLE SUBSIDENCE
FROM THE MCV ALOFT/...THINK THE 00Z NAM IS BE TO PESSIMISTIC IN
KEEPING A COOL AND STABLE BOUNDARY LAYER ACROSS NORTHEAST KS.
LOOKING AT THE NEW 06Z NAM...IT APPEARS TO BE TRENDING TOWARDS THE
HIGHER RESOLUTION HRRR AND RAP13 IN BRINGING A BREAK TO THE PRECIP
BY LATE MORNING. WITH THE SURFACE LOW STILL OVER THE PANHANDLES AND
ANY REMAINING OUTFLOW BOUNDARY WELL TO THE SOUTH OF THE FORECAST
AREA...THINK DECENT INSOLATION SHOULD ALLOW THE BOUNDARY LAYER TO
RECOVER AND BECOME CONDITIONALLY UNSTABLE WITH THE TROUGH AXIS AND
LOW LEVEL CONVERGENCE ALONG IT ACTING AS THE FOCUS FOR THE
REDEVELOPMENT OF STORMS LATE THIS AFTERNOON. DEEP LAYER SHEAR
CONTINUES TO LOOK MARGINAL. ADDITIONALLY THE RAP SHOWS 0-1KM SHEAR
PARAMETERS ON THE WARM SIDE OF THE TROUGH TO BE RELATIVELY LOW. SO
WOULD ANTICIPATE STORMS TO QUICKLY EVOLVE INTO A MULTI-CELL
CONFIGURATION WITH PRIMARY SEVERE WEATHER THREATS OF MAINLY HAIL AND
POSSIBLY SOME DAMAGING WIND GUSTS.
WITH THE BOUNDARY LAYER EXPECTED TO RECOVER...HAVE AFTERNOON HIGHS
IN THE MID TO UPPER 70S. THE POP FORECAST SHOWS A DECREASING TREND
THROUGH THE LATE MORNING. THEN CHANCES SHOULD BE ON THE INCREASE
DURING THE AFTERNOON WITH THUNDERSTORM INITIATION POSSIBLE BETWEEN 3
AND 6 PM. AS SHORTWAVE ENERGY LIFTS OUT OF THE SOUTHWEST ALONG THE
SURFACE BOUNDARY...COVERAGE OF SHOWERS AND THUNDERSTORMS IS LIKELY
TO INCREASE AND HAVE POPS INCREASING TO AROUND 80 PERCENT BY THIS
EVENING. LOW TONIGHT SHOULD BE ON THE MILD SIDE SINCE THERE IS NOT A
GREAT DEAL OF COLD AIR ON THE NORTHERN SIDE OF THE SURFACE TROUGH.
SO LOWS ARE FORECAST TO BE IN THE MID 50S ACROSS NORTH CENTRAL
KS...WHERE WINDS SHOULD SHIFT TO THE NORTH BY DAYBREAK THURSDAY...TO
THE UPPER 50S ACROSS EAST CENTRAL KS WHICH IS LIKELY TO REMAIN ON
THE WARM SIDE OF THE TROUGH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 356 AM CDT WED MAY 8 2013
ON THURSDAY...THE FRONT WILL CONTINUE TO SAG SOUTHWARD AS THE
SHORTWAVE TROUGHS TO THE NORTHEAST AND WEST OF THE CWA BECOME MORE
POSITIVE TILT AND DRIFT SOUTHEASTWARD AS WELL. THIS WILL RESTRICT
THE HIGHER POPS ACROSS THE COUNTY WARNING AREA TO AREAS SOUTH AND
EAST OF THE I 35 CORRIDOR AND PRIMARILY IN THE MORNING...THEN ONLY
SLIGHT CHANCE AND LOW END CHANCE POPS IN THE AFTERNOON. ALTHOUGH
HAVE KEPT DECREASING POPS INTO FRIDAY WITH THE PASSAGE OF ANOTHER
WAVE IN NORTHWEST FLOW...ANY SCATTERED RAINFALL AMOUNTS WOULD
LIKELY ONLY BE A FEW HUNDREDTHS OF AN INCH. IF TRENDS
CONTINUE...ADDITIONAL PORTIONS OF THE CWA (OTHER THAN THE
NORTHWEST COUNTIES) MAY NEED TO HAVE PRECIP CHANCES REMOVED ON
FRIDAY. HIGHS IN THE LOWER 70S FOR THURSDAY SHOULD BE A FEW
DEGREES COOLER IN THE UPPER 60S TO LOWER 70S FOR FRIDAY.
A STRONGER WAVE WILL HOWEVER MOVE ACROSS CWA ON SATURDAY
WITH ANOTHER CHANCE FOR SHOWERS/THUNDER PRIMARILY ACROSS THE
SOUTHERN CWA. THIS WAVE WILL PUSH A STRONG COLD FRONT THRU THE CWA
WITH MUCH COOLER TEMPERATURES IN ITS WAKE AND MAY EVEN RESULT IN
STEADY OR SLOWLY FALLING TEMPS MANY AREAS IN THE AFTERNOON AFTER
MIDDAY HIGHS IN THE MIDDLE TO UPPER 60S. THIS WILL SET THE STAGE FOR
ANOTHER UNSEASONABLY COOL MORNING ON SUNDAY WITH READINGS IN THE
UPPER 30S NORTHEAST TO THE LOWER 40S ELSEWHERE. THIS SHOT OF COLD
AIR HOWEVER WILL BE BRIEF AS THE EASTERN TROUGH SHIFTS EASTWARD AND
UPSTREAM RIDGING IN THE WESTERN CONUS ADVANCES INTO THE PLAINS WITH
DRY WEATHER INTO NEXT WEEK. AFTER HIGHS IN THE MIDDLE 60S ON
SUNDAY...HIGHS FOR MONDAY SHOULD REBOUND BACK INTO THE MIDDLE AND
UPPER 70S AS WEST TO SOUTHWESTERLY LLVL FLOW BECOMES MORE
ESTABLISHED ACROSS THE AREA. HIGHS ON TUESDAY SHOULD THEN TOP OUT IN
THE LOW TO MIDDLE 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 356 AM CDT WED MAY 8 2013
CONVECTIVE COMPLEX EXPECTED TO CONTINUE EAST INTO THE TERMINALS
THROUGH 08-10Z...WITH ADDITIONAL DEVELOPMENT ONGOING IN SOUTHWEST
KANSAS AND LIKELY TO JOIN THE COMPLEX INTO THE POST-SUNRISE HOURS
PER RECENT HRRR AND NAM RUNS. LIMITATIONS SHOULD REMAIN WITH
VISIBILITIES DOWN TO MVFR LEVELS WITH THE STRONGER CELLS. BACKED
OFF WITH ADDITIONAL DEVELOPMENT GIVEN SLOWER BOUNDARY AND SOME
TIME FOR ATMOSPHERE TO RECOVER.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...63
AVIATION...65
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1151 PM CDT TUE MAY 7 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT TUE MAY 7 2013
A BLOCKING PATTERN WAS IN PLACE OVER THE REGION TODAY AS UPPER LEVEL
LOWS WERE SITUATED OVER BOTH THE SOUTHEASTERN AND SOUTHWESTERN U.S.
WITH A WEAK RIDGE OVER THE SOUTHERN PLAINS. A SHORTWAVE THAT WAS
EMBEDDED IN THE RIDGE LIFTED NORTHWARD INTO KANSAS TODAY. ENOUGH
LIFT WAS PRESENT WITH THIS WAVE TO AID IN THE DEVELOPMENT OF SHOWERS
ACROSS WESTERN AND CENTRAL KANSAS THIS MORNING INTO THIS AFTERNOON.
HOWEVER...LATEST RADAR TRENDS SHOW THIS LINE OF SHOWERS OVER CENTRAL
KANSAS BEGINNING TO WEAKEN AND DISSIPATE AS THEY TRACK FURTHER EAST
AS A RESULT OF THE WAVE WEAKENING AS IT BECOMES WRAPPED UP IN THE
BROAD UPPER LOW STATIONED ACROSS THE NORTHERN PLAINS. HAVE TRENDED
DOWN WITH POPS ACROSS MUCH NORTHEASTERN AND EAST CENTRAL KANSAS
THROUGH THE EARLY EVENING HOURS WITH CHANCE POPS IN PLACE OVER NORTH
CENTRAL KANSAS AS THE WAVE PASSES OVER THE AREA. THIS WAVE LOOKS TO
AMPLIFY A BIT AS IT TRACKS EASTWARD ACROSS NORTHERN KANSAS OVERNIGHT
INTO WEDNESDAY MORNING...SO HAVE INCREASING POPS OVER THIS AREA.
WITH A SOUTHERLY FLOW IN PLACE OVER THE REGION THROUGH THE OVERNIGHT
HOURS...THE COMBINATION OF WAA AND INCREASING CLOUD COVER WILL ALLOW
FOR SOME ISOLATION OVERNIGHT AND LOW TEMPERATURES TO ONLY DROP INTO
THE MIDDLE 50S.
SCATTERED SHOWERS WITH SOME ELEVATED THUNDERSTORMS MAY SPREAD
EASTWARD ACROSS THE FORECAST AREA THROUGH THE MORNING HOURS AS THE
WAVE PROGRESSES EAST OF THE CWA BY WEDNESDAY AFTERNOON. THERE IS
SOME UNCERTAINTY REGARDING HOW MUCH SUN WILL BE ABLE TO BREAK
THROUGH THE CLOUDS BEHIND THIS EXITING WAVE...WHICH WILL EFFECT HOW
MUCH HEATING WILL BE ABLE TO OCCUR TO CAUSE SOME DESTABILIZATION
OVER THE REGION THROUGH THE AFTERNOON HOURS. AT THIS
TIME...AFTERNOON HIGHS FOR WEDNESDAY SHOULD REACH INTO THE LOWER TO
MIDDLE 70S. WHILE THE BETTER POTENTIAL FOR THUNDERSTORM DEVELOPMENT
LOOKS TO BE IN THE VICINITY OF THE DRYLINE THAT SETS UP OVER WESTERN
OKLAHOMA AND SOUTHWESTERN KANSAS...ADDITIONAL DEVELOPMENT IS
POSSIBLE ACROSS THE FORECAST AREA BY MID TO LATE AFTERNOON IF ENOUGH
DESTABILIZATION OCCURS. MODELS SHOW A BOUNDARY EXTENDING FROM THE
SURFACE LOW OVER THE TEXAS/OKLAHOMA PANHANDLES AND STRETCHING
NORTHEASTWARD INTO NORTH CENTRAL KANSAS BEFORE GRADUALLY SHIFTING
SOUTHWARD ACROSS THE FORECAST AREA THROUGH THE EVENING HOURS. THERE
IS STILL SOME UNCERTAINTY REGARDING THE EXACT LOCATION OF THIS
BOUNDARY BY LATE AFTERNOON...WHICH WILL EFFECT WHERE THE GREATEST
POTENTIAL FOR ANY THUNDERSTORM DEVELOPMENT WILL BE.
HENNECKE
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 PM CDT TUE MAY 7 2013
WEDNESDAY NIGHT...A BROAD UPPER LEVEL TROUGH OVER THE FOUR
CORNERS AREA 00Z THU WILL FILL AS IT LIFTS EAST-NORTHEAST INTO THE
CENTRAL AND SOUTHERN PLAINS. A SURFACE COLD FRONT WILL PUSH
SOUTHWARD ACROSS THE CWA DURING THE NIGHT. ONGOING THUNDERSTORMS
ALONG AND SOUTH OF THE SURFACE FRONT WILL CONTINUE THROUGH THE
NIGHT. SOME OF THE THUNDERSTORMS DURING THE EVENING HOURS MAY BE
SEVERE AS SBCAPE WILL BE AROUND 1500 J/KG AND SFC TO 6KM BULK
SHEAR WILL BE ABOUT 30 KTS THROUGH 3Z. THE PRIMARY HAZARDS WITH
ANY ORGANIZED SEVERE SURFACE BASED STORM WILL BE LARGE HAIL AND
ISOLATED DAMAGING WIND GUSTS. NORTH OF THE BOUNDARY ELEVATED
THUNDERSTORMS MAY PRODUCE PENNY TO QUARTER SIZE HAIL. IF THE
SURFACE FRONT REMAINS STATIONARY ACROSS THE CENTRAL PORTIONS OF
THE CWA EARLY WEDNESDAY EVENING...THEN AN ORGANIZED SUPERCELL MAY
RIDE ALONG THE BOUNDARY AND INGEST BAROCLINICALLY GENERATED
STREAM-WISE HORIZONTAL VORTICITY AND MAY PRODUCE ISOLATED
TORNADOES. HOWEVER...IF THE FRONT SLOWLY MOVES SOUTHEAST ACROSS
THE CWA...THEN MOST LIKELY THE SURFACE FRONT WILL UNDERCUT ANY
SURFACE BASED INFLOW AND DIMINISH THE THREAT FOR ISOLATED
TORNADOES.
ISENTROPIC LIFT NORTH OF THE BOUNDARY WILL KEEP RAIN AND ELEVATED
THUNDERSTORMS CHANCES THROUGH THE NIGH. BOTH THE NAM AND ECMWF SHOW
THE INSTABILITY DECREASING THROUGH THE NIGHT TO LESS THAN 500 J/KG
AFTER MIDNIGHT. THUS ANY STRONG ELEVATED STORMS AFTER MIDNIGHT WILL
ONLY PRODUCE SMALL HAIL.
THURSDAY AND THURSDAY NIGHT...SKIES WILL BE MOSTLY CLOUDY WITH
PERIODS OF SHOWERS AND ISOLATED ELEVATED THUNDERSTORMS. MUCAPE NORTH
OF THE FRONT WILL ONLY RANGE FROM 100-400 J/KG...THUS THE STRONGER
ELEVATED THUNDERSTORMS WILL ONLY PRODUCE SMALL HAIL.
FRIDAY...THE SHOWERS SHOULD END FROM NORTH TO SOUTH ACROSS THE CWA
AS THE H5 TROUGH ACROSS NORTHERN MO SHEARS APART.
FRIDAY NIGHT...SHOULD REMAIN DRY AS AN H5 TROUGH DIGS SOUTHEAST FROM
CENTRAL CANADA INTO THE UPPER MIDWEST.
SATURDAY AND SATURDAY NIGHT...THE H5 TROUGH WILL DIG AND AMPLIFY
ACROSS THE SOUTHERN GREAT LAKES STATES. THIS WILL CAUSE A COLD FRONT
TO RAPIDLY PUSH SOUTHEAST ACROSS THE CWA DURING THE MID AND LATE
MORNING HOURS OF SATURDAY. THERE MAY BE ENOUGH LIFT AHEAD OF THE
FRONT AND ON THE WESTERN EDGE OF THE H5 TROUGH TO CAUSE A FEW
ISOLATED SHOWERS OR THUNDERSTORMS...BUT THESE SHOWERS SHOULD PUSH
SOUTHEAST OF THE CWA DURING THE EARLY AFTERNOON HOURS. NORTH WINDS
WILL INCREASE TO 15 TO 20 MPH WITH SOME GUSTS TO 30 MPH. HIGH
TEMPERATURES WILL PROBABLY OCCUR DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS IN THE LOWER TO MID 60S AND THEN HOLD STEADY OR EVEN
FALL SLIGHTLY DURING THE AFTERNOON HOURS. THE CENTER OF THE SURFACE
RIDGE WILL BUILD SOUTHWARD ACROSS EASTERN KS SATURDAY NIGHT. LIGHT
WINDS AND CLEAR SKIES WILL ALLOW TEMPERATURES TO DROP INTO THE
UPPER 30S TO LOWER 40S. DEWPOINT TEMPERATURES SHOULD BE IN THE UPPER
20S...SO I DON`T THINK FROST WILL FORM.
SUNDAY AND SUNDAY NIGHT...WILL BE ANOTHER COOL DAY WITH HIGHS IN THE
MID 60S. LIGHT WINDS WILL BECOME SOUTHERLY THROUGH THE LATE
AFTERNOON AND INTO THE NIGHT. SOUTHERLY SURFACE WINDS WILL KEEP
OVERNIGHT LOWS IN THE MID 40S.
MONDAY THROUGH TUESDAY...EXPECT A WARMING TREND AS AN H5 RIDGE
MOVES EAST ACROSS THE PLAINS. SOUTHERLY WINDS WILL HELP HIGHS TO
WARM INTO THE MID 70S ON MONDAY AND INTO THE LOWER TO MID 80S ON
TUESDAY.
GARGAN
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM CDT TUE MAY 7 2013
CONVECTIVE COMPLEX EXPECTED TO CONTINUE EAST INTO THE TERMINALS
THROUGH 08-10Z...WITH ADDITIONAL DEVELOPMENT ONGOING IN SOUTHWEST
KANSAS AND LIKELY TO JOIN THE COMPLEX INTO THE POST-SUNRISE HOURS
PER RECENT HRRR AND NAM RUNS. LIMITATIONS SHOULD REMAIN WITH
VISIBILITIES DOWN TO MVFR LEVELS WITH THE STRONGER CELLS. BACKED
OFF WITH ADDITIONAL DEVELOPMENT GIVEN SLOWER BOUNDARY AND SOME
TIME FOR ATMOSPHERE TO RECOVER.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HENNECKE
LONG TERM...GARGAN
AVIATION...65
AREA FORECAST DISCUSSION
NWS PADUCAH KY
300 PM CDT WED MAY 8 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM CDT WED MAY 8 2013
THE LATEST AVAILABLE HRRR OUTPUT DEVELOPS AT LEAST SCATTERED
CONVECTION AHEAD OF THE MCV MOVING OVER CENTRAL MISSOURI. STARTING
TO SEE SOME ENHANCEMENT ON VISIBILTY SATELLITE IMAGERY AND SOME
SHOWER DEVELOPMENT TO OUR WEST/NORTHWEST ON RADAR. DECIDED TO
INCREASE POPS UP TO LOWER CHANCE LEVELS COMING OUT OF THE OZARK
FOOTHILLS THROUGH SUNSET. THE HRRR DISSIPATES THE STRONGER
ELEMENTS AS THEY APROACH THE MISSISSIPPI RIVER AROUND 02Z.
FOLLOWED THE HRRR CLOSELY INTO THE EVENING...AND WILL HAVE A DRY
FORECAST BY 03Z. ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTHWEST
INDIANA AND THE PENNYRILE THIS AFTERNOON SHOULD DISSIPATE OR MOVE
SOUTH/EAST OF THE AREA BY SUNSET.
THE 12Z MODELS ARE TRENDING DRIER FOR LATER TONIGHT AND ESPECIALLY
THURSDAY. SOUNDINGS INDICATE THAT A WEAK CAP WILL BE SUFFICIENT TO
KEEP MOST AREAS DRY...DUE TO A GENERAL LACK OF DEEP MOISTURE OR
MAJOR FORCING. WILL SPREAD GOOD CHANCE POPS EASTWARD ALONG THE
I-64 CORRIDOR THROUGH THE MORNING AND KEEP THEM AT THAT LEVEL THERE
THROUGH THE AFTERNOON AND INTO THE EVENING. THIS AREA WILL BE
CLOSEST TO ANY EFFECTS OF MID/UPPER LEVEL DISTURBANCES AND THE
FRONT ITSELF. WOULD BE VERY SURPRISED TO SEE ANYTHING MORE THAN A
VERY ISOLATED STORM PULSE UP TO NEAR SEVERE LEVELS ALONG I-64
THURSDAY AFTERNOON. WILL KEEP SLIGHT CHANCES TO THE SOUTH JUST IN
CASE WE DESTABILIZE ENOUGH FOR A PARCEL TO BREAK THROUGH DURING
THE AFTERNOON.
THURSDAY WILL SEE INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS...AS THE COLD FRONT AND IMPACTS OF THE PRIMARY
MID/UPPER LEVEL DISTURBANCE APPROACH THE AREA. THE LLJ WILL
INCREASE TO AROUND 35KTS...WHICH SHOULD HELP TO BRING SOME
BETTER...DEEPER MOISTURE NORTHEAST ACROSS MUCH OF THE AREA. WILL
HAVE A SOUTHWEST TO NORTHEAST BAND OF LIKELY POPS OVER SOUTHEAST
MISSOURI AND SOUTHERN ILLINOIS LATE IN THE EVENING...AND THEN MOVE
IT SLOWLY EASTWARD ACROSS THE REMAINDER OF THE AREA OVERNIGHT.
THE MODELS SEEM TO HAVE CONVERGED FOR FRIDAY. A WEAK COLD FRONT
WILL SLOWLY PUSH EASTWARD ACROSS THE AREA THROUGH THE DAY AND
SHOULD CLEAR THE ENTIRE AREA BY EARLY EVENING. WITH THE FRONT AND
THE MAIN MID/UPPER DISTURBANCE OVER THE AREA FRIDAY...LIKELY POPS
SEEM WARRANTED...WITH AN EMPHASIS OVER WEST KENTUCKY. A LACK OF
FORCING...ONLY WEAK INSTABILITY...AND GENERALLY WEAK WIND PROFILES
SHOULD KEEP ANY CONVECTION WELL BELOW SEVERE LIMITS. SOME VERY
LOCALIZED HEAVY RAINFALL SHOULD BE THE PRIMARY CONCERN FRIDAY.
POPS WILL LINGER INTO FRIDAY EVENING...MAINLY IN THE EAST...BUT
THE MODEL CONSENSUS IS FOR THE ENTIRE AREA TO BE DRY BY 06Z SATURDAY.
AS FOR TEMPERATURES...WENT ON HIGH END OF GUIDANCE FOR HIGHS
THURSDAY...AND TOWARD THE COOL SIDE FRIDAY. WENT A BIT ABOVE
GUIDANCE FOR LOWS FRIDAY NIGHT. OTHERWISE...CONSENSUS OF GUIDANCE
SHOULD BE FINE.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT WED MAY 8 2013
OVER THE WEEKEND...A CLOSED LOW OVER ONTARIO AT THE START OF THE
PERIOD...MOVES EAST AND ENDS UP CARVING A DEEP TROUGH OVER THE GREAT
LAKES AND DOWN INTO OUR REGION. A SECONDARY FRONT MOVES SOUTH TOWARD
US ON SATURDAY AND WHILE IT SEEMS TO START OUT WITH ENOUGH MOISTURE
TO OUR NORTH...BY THE TIME THE FRONT GETS HERE SATURDAY
EVENING...NOT MUCH MOISTURE IS LEFT. SO OPTED TO REMOVE ALL POPS FOR
SATURDAY.
BEHIND THE SECONDARY COLD FRONT...MUCH COOLER AIR WILL FILTER INTO
THE AREA SATURDAY NIGHT AND INTO SUNDAY...ON THE NOSE OF SFC HIGH
PRESSURE FROM CANADA. THE 00Z/12Z ECMWF AND 06Z/12Z GFS INDICATE
850MB TEMPS AT OR BELOW ZERO IN OUR FAR NORTHERN COUNTIES.
HOWEVER...SINCE HIGH PRESSURE WILL STILL BE MOVING IN...THE WIND
WILL LIKELY STAY UP WHICH WILL PREVENT US FROM DROPPING TOO LOW ON
OUR LOW TEMPS FOR SATURDAY NIGHT.
THE SFC HIGH WILL FINALLY BEGIN TO SETTLE OVER THE AREA ON SUNDAY
AND SUNDAY NIGHT...WITH ALL INDICATIONS THAT THE CENTER OF THE HIGH
WILL BE DIRECTLY OVER US ON 12Z MONDAY. WITH COLD AIR ADVECTION IN
FULL SWING ON SUNDAY...WOULD VENTURE TO GUESS WE WILL NOT GET OUT OF
THE 60S FOR HIGHS. THE COLDEST AIR WILL BE SITUATED OVER OUR
NORTHEASTERN COUNTIES (NAMELY SE IL...SWIN...PENNYRILE). LOOKING AT
CIPS ANALOG DATA ALONG WITH RECORDS FROM XMACIS...WE COULD BE
LOOKING AT LOWS SUNDAY NIGHT FALLING INTO THE UPPER 30S FOR THESE
PORTIONS OF OUR AREA IF THE GFS IS CORRECT. 850 MB TEMPS OFF THE GFS
AND THE GFS ENSEMBLE MEAN ARE A BIT COOLER THAN THE ECMWF...AND WITH
CALM WINDS AND CLEAR SKIES...WE COULD DROP QUITE A BIT. LOOKING AT
RAW MODEL DEWPOINT TEMPS...THIS ALSO SUPPORTS THESE COOLER
TEMPS...WHICH COULD GET CLOSE TO TYING RECORDS IN THE EVV AREA.
ELSEWHERE THOUGH...IT STILL LOOKS COOL WITH LOWS IN THE LOWER 40S.
AGAIN...THIS MAY BE COLD ENOUGH TO SUPPORT THE FORMATION OF VERY
PATCHY FROST IN OUTLYING AREAS...BUT A WIDESPREAD FROST IS STILL NOT
ANTICIPATED ATTM.
THE SFC HIGH MOVES EAST AND EVENTUALLY SOUTH ON MONDAY/MONDAY NIGHT AND
THAT IS WHEN THE WARM UP WILL BEGIN. DEPENDING ON HOW LOW WE START
THE DAY WITH ON MONDAY...WE WILL STILL BE COOL WITH HIGHS REMAINING
IN THE 60S/POSSIBLY AROUND 70 FAR WEST. THE FLOW IN THE LOW LEVELS
BECOMES SOUTHERLY/SOUTHWESTERLY LATE MONDAY NIGHT INTO TUESDAY AND
850 MB TEMPS WILL RISE STEADILY FROM THEN THROUGH THE END OF THE
EXTENDED PERIOD (WEDNESDAY). THEREFORE...WE EXPECT HIGHS IN THE 70S
ON TUESDAY WITH AROUND 80 ON WEDNESDAY. THIS EARLY WEEK PERIOD
CONTINUES TO BE DRY. LOOKING BEYOND THAT...MODELS TRY TO BRING A
FRONT INTO THE AREA BUT DIFFER ON TIMING.
&&
.AVIATION...
ISSUED AT 1231 PM CDT WED MAY 8 2013
A STRAY SHOWER MAY FLIRT WITH KEVV AND KOWB THIS AFTERNOON...BUT
CONFIDENCE IS TOO LOW AT THIS TIME TO INCLUDE EVEN A VCSH. WILL
MONITOR RADAR/SATELLITE TRENDS AND ADD IN SHRA/TSRA AS NEEDED THIS
AFTERNOON. DO NOT FEEL THAT ANY ACTIVITY OVER SOUTHEAST MISSOURI
THIS AFTERNOON WILL IMPACT KCGI...SO KEPT IT DRY AS WELL.
GUIDANCE INDICATES THAT MID-LEVEL CEILINGS WILL OVERSPREAD THE
AREA FROM WEST TO EAST TONIGHT. A LIGHT SOUTH WIND IS EXPECTED TO
DEVELOP IN THE WEST TONIGHT...BUT WINDS WILL LIKELY BE CALM IN THE
EAST. CONSIDERED ADDING FOG OVERNIGHT IN THE EAST...BUT DECIDED
AGAINST IT...AS MID CLOUDS SHOULD BE ON THE INCREASE OVERNIGHT
RIGHT WHEN THE FOG WOULD OTHERWISE BE DEVELOPING.
FEEL THAT ANY CONVECTION LATE TONIGHT OR THURSDAY WILL REMAIN TO
THE NORTH AND WEST OF THE TAF SITES. WILL SEE SOME CU UNDER A
CEILING AOA 15KFT THURSDAY MORNING. WINDS WILL BE INCREASING FROM
THE SOUTH...ESPECIALLY AT KCGI AND KPAH...WHERE GUSTS WELL OVER
20KTS WILL BE POSSIBLE.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...DRS
LONG TERM...CW
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1231 PM CDT WED MAY 8 2013
.UPDATE...
ISSUED AT 1231 PM CDT WED MAY 8 2013
THE PUBLIC FORECAST WAS UPDATED EARLIER THIS MORNING. TEMPERATURES
GOT OFF TO A FAST START...AND THE RUC TEMPERATURES INDICATE HIGHS
AROUND 80 THROUGHOUT THE AREA. ALSO...THE NAM AND HRRR DEVELOP
SOME SHOWERS AND POSSIBLY THUNDERSTORMS OVER SOUTHEAST MISSOURI.
THIS CONVECTION WOULD BE A COMBINATION OF WARMER THAN EXPECTED
TEMPERATURES AND A DISTURBANCE MOVING ACROSS CENTRAL MISSOURI
THROUGH THE AFTERNOON. ALL INDICATIONS ARE THAT THIS ACTIVITY WILL
BE DIURNAL IN NATURE...THEREFORE WOULD NOT EXPECT MUCH IF ANY
ACTIVITY LEFT AFTER 00Z. A SLIGHT CHANCE OF SHOWERS AND STORMS
REMAINS IN THE FORECAST FOR THE EASTERN THIRD OF THE AREA THIS
AFTERNOON.
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 18Z TAF ISSUANCE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT WED MAY 8 2013
WILL CONTINUE WITH SLIGHT CHANCE POPS ACROSS THE PENNYRILE REGION
TODAY AND A LIMITED CHANCE IN THE OZARK FOOTHILL REGION. OTHERWISE
MAINLY DRY MOST AREAS WITH HIGHS A LITTLE WARMER THAN YESTERDAY.
SHOULD BE MAINLY DRY TONIGHT. MODELS SLOWER THEN PREVIOUS TWO DAYS
BRINGING CHANCE OF CONVECTION INTO THE REGION. THEREFORE WILL HOLD
OFF POPS TIL THURSDAY AND RAMP THEM UP THURSDAY NIGHT INTO FRIDAY
AS A FRONT MOVES TOWARD AND THEN THROUGH THE AREA. AM NOT CONCERNED
WITH SEVERE WEATHER AT THIS TIME. A STRONG STORM OR TWO CANNOT BE
RULED OUT. CHANCES SHOULD GRADUALLY LOWER FROM NORTHWEST TO
SOUTHEAST FRIDAY NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 252 AM CDT WED MAY 8 2013
MOST OF THE PRECIPITATION WITH THE FIRST COLD FRONT SHOULD BE EAST
OF THE REGION BY 12Z SATURDAY. HOWEVER...THE MOST NOTICEABLE CHANGE
IN AIR MASS WILL NOT OCCUR UNTIL A SECONDARY COLD FRONT PASSES
ACROSS THE REGION SATURDAY AFTERNOON AND EVENING. WHILE ALL MODELS
CONTINUE TO INDICATE A DRY FRONTAL PASSAGE...THEY DO DEVELOP SPOTTY
PRECIPITATION JUST NORTH OF THE REGION AS THE FRONT APPROACHES
SATURDAY AFTERNOON. FOR THIS REASON...WILL MAINTAIN GOING SLIGHT
CHANCE MENTION OF THUNDER DURING THE DAYLIGHT HOURS SATURDAY.
ONCE THE FRONT PASSES THROUGH...A TRANSITION TO DRY AND UNSEASONABLY
COOL WEATHER IS EXPECTED ON SUNDAY. HIGHS IN THE LOWER 60S WILL BE
ABOUT 15 DEGREES BELOW NORMAL. SUNDAY NIGHT LOOKS LIKE THE COLDEST
NIGHT WITH LOWS NEAR THE 40 DEGREE MARK. THIS MAY BE COLD ENOUGH TO
SUPPORT THE FORMATION OF VERY PATCHY FROST IN OUTLYING AREAS...BUT A
WIDESPREAD FROST IS NOT ANTICIPATED.
A WARMING TREND WILL TAKE PLACE DURING THE FIRST HALF OF NEXT WEEK
AS AN UPPER LEVEL RIDGE BUILDS EAST FROM THE PLAINS AND SOUTHERLY
FLOW DEVELOPS ON THE BACK SIDE OF THE DEPARTING SURFACE HIGH. HIGHS
WILL MODERATE FROM THE UPPER 60S ON MONDAY INTO THE MID 70S BY
TUESDAY. WEDNESDAY LOOKS EVEN WARMER AS TEMPERATURES NEAR THE 80
DEGREE MARK.
&&
.AVIATION...
ISSUED AT 1231 PM CDT WED MAY 8 2013
A STRAY SHOWER MAY FLIRT WITH KEVV AND KOWB THIS AFTERNOON...BUT
CONFIDENCE IS TOO LOW AT THIS TIME TO INCLUDE EVEN A VCSH. WILL
MONITOR RADAR/SATELLITE TRENDS AND ADD IN SHRA/TSRA AS NEEDED THIS
AFTERNOON. DO NOT FEEL THAT ANY ACTIVITY OVER SOUTHEAST MISSOURI
THIS AFTERNOON WILL IMPACT KCGI...SO KEPT IT DRY AS WELL.
GUIDANCE INDICATES THAT MID-LEVEL CEILINGS WILL OVERSPREAD THE
AREA FROM WEST TO EAST TONIGHT. A LIGHT SOUTH WIND IS EXPECTED TO
DEVELOP IN THE WEST TONIGHT...BUT WINDS WILL LIKELY BE CALM IN THE
EAST. CONSIDERED ADDING FOG OVERNIGHT IN THE EAST...BUT DECIDED
AGAINST IT...AS MID CLOUDS SHOULD BE ON THE INCREASE OVERNIGHT
RIGHT WHEN THE FOG WOULD OTHERWISE BE DEVELOPING.
FEEL THAT ANY CONVECTION LATE TONIGHT OR THURSDAY WILL REMAIN TO
THE NORTH AND WEST OF THE TAF SITES. WILL SEE SOME CU UNDER A
CEILING AOA 15KFT THURSDAY MORNING. WINDS WILL BE INCREASING FROM
THE SOUTH...ESPECIALLY AT KCGI AND KPAH...WHERE GUSTS WELL OVER
20KTS WILL BE POSSIBLE.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 AM EDT WED MAY 8 2013
.UPDATE...
ISSUED AT 133 AM EDT WED MAY 8 2013
MADE A QUICK UPDATE TO THE FORECAST. NO MAJOR CHANGES WERE MADE TO
THE FORECAST GRIDS THEMSELVES...BUT WITH LOCALLY DENSE FOG SHOWING UP
IN OBS ACROSS EASTERN KENTUCKY...DECIDED TO GO AHEAD AND MENTION THE
POSSIBILITY OF LOCALLY DENSE FOG IN THE ZONE FORECAST TEXT PRODUCT.
THE GRIDS ALREADY HAVE PATCHY DENSE FOG IN THE WEATHER TYPE ELEMENT
THROUGH 12Z THIS MORNING...SO IT WAS JUST A MATTER OF MENTIONING IT
IN THE FORECAST TEXT PRODUCT AND HAZARDOUS WEATHER OUTLOOK. WILL
ISSUE TO UPDATED ZONES SHORTLY.
UPDATE ISSUED AT 830 PM EDT TUE MAY 7 2013
HOURLY POPS...TEMPS AND DEWPOINTS WERE UPDATED BASED ON RECENT
TRENDS RADAR...SATELLITE AND MODEL TRENDS. SOME OF THE MODELS...
PARTICULARLY RECENT HRRR...ARE HANDLING THE BAND OF SHOWERS MOVING
ACROSS THE SOUTHWEST HALF OF THE CWA RATHER WELL. THE NAM AND THE GFS
BRING ANOTHER WEAK SHORTWAVE AROUND THE MAIN CIRCULATION AND
SPREAD SOME SHOWERS INTO THE SOUTHEASTERN COUNTIES LATER TONIGHT...
TOWARD DAWN. THE NAM AND HRRR MINIMIZE THIS MORE THAN THE GFS AND
CONFINE IT MORE TO FAR SOUTHEAST KY. NO THUNDER HAS BEEN OBSERVED OVER
THE PAST HOUR SO WE HAVE OPTED TO REMOVE THUNDER FROM THE FORECAST
OVERNIGHT. FOG HAS ALREADY DEVELOPED IN THE JKL VICINITY AND VALLEYS
NEAR WHERE PRECIPITATION WAS HEAVIER IN THE EVENING. SO FOG SHOULD
CONTINUE EARLIER THAN CLIMATOLOGY AND AND IF SKIES REMAIN CLEAR
ENOUGH IT MAY BECOME DENSE AROUND OR SOON AFTER MIDNIGHT IN SOME
AREAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM EDT TUE MAY 7 2013
STACKED AND WEAKENING LOW PRESSURE WAS OVER THE CAROLINAS THIS
AFTERNOON AND WAS MOVING NE. PRECIP ASSOCIATED WITH THE LOW WAS OVER
WV AND ROTATING WESTWARD IN KY. MODELS SHOW IT TAKING A TURN TO THE
SOUTHWEST AND THEN THE SOUTH THIS EVENING AS IT MOVES AROUND THE
DEPARTING LOW. THIS PLACES THE GREATEST POTENTIAL FOR PRECIP IN OUR
EASTERN COUNTIES THIS EVENING. THERE HAVE BEEN A FEW SPARSE LIGHTNING
STRIKES TO OUR EAST...AND WITH MEAGER HEATING WHICH HAS TAKEN PLACE
LOCALLY...WILL CARRY A SLIGHT CHANCE OF THUNDER HERE INTO THIS
EVENING. AS HEATING IS LOST AND THE LOW SLOWLY MOVES AWAY...THERE
SHOULD BE AN OVERALL DECREASE IN PRECIP OVERNIGHT.
ON WEDNESDAY...HEATING SHOULD YIELD ENOUGH INSTABILITY TO CAUSE
SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP OVER THE AREA ON THE EDGE
OF THE DEPARTING LOW. WILL LOOK FOR A DIURNAL TREND...WITH THE
ACTIVITY DYING OFF IN THE EVENING. THERE SHOULD BE MORE IN THE WAY OF
CLEARING ON WEDNESDAY NIGHT AS MID/UPPER LEVEL RIDGING BUILDS IN.
WITH RAIN LIKELY BEFORE THIS... FOLLOWED BY LIGHT WINDS...AND NO
CHANGE IN SURFACE AIR MASS...THIS COULD RESULT IN QUITE A FOGGY
NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 359 PM EDT TUE MAY 7 2013
MODELS ARE IN GOOD AGREEMENT THROUGH THE EXTENDED PORTION OF THE
FORECAST. PESKY SLOW MOVING UPPER LEVEL LOW WILL FINALLY BE EXITING
TO OUR NORTHEAST. SHORT WAVE RIDGING WILL BUILD IN BRIEFLY AT THE
START OF THE PERIOD. BUT ANOTHER DISTURBANCE WILL MOVE QUICKLY INTO
THE REGION FROM OUT OF THE SOUTHWESTERN CONUS TO FINISH OUT THE
WEEK. THIS NEXT DISTURBANCE COMBINED WITH A LARGER...MORE ORGANIZED
SYSTEM DROPPING SOUTHWARD OUT OF CANADA WILL KEEP UNSETTLED WEATHER
IN THE FORECAST THROUGH MUCH OF THE UPCOMING WEEKEND. IN GENERAL...
FORECAST SOUNDINGS ARE SHOWING ENOUGH SURFACE BASED INSTABILITY TO
INCLUDE THUNDER WHENEVER POPS ARE MENTIONED THROUGH SATURDAY. THERE
IS A DIURNAL FLAVOR TO SHOWER AND THUNDERSTORM ACTIVITY AS WELL. AM
NOT CONVINCED SHOWER AND THUNDERSTORMS WILL BE AS PREVALENT AS
RECENTLY ADVERTISED FOR THURSDAY. AFOREMENTIONED SHORT WAVE RIDGING
APPEARS STRONG ENOUGH TO DEVELOP A CAP...SHOWING UP ON FORECAST
SOUNDINGS THAT SHOULD HELP KEEP ACTIVITY LOW IF NOT AT A MINIMUM. A
COUPLE OF THE MODELS...PARTICULARLY THE NAM DOES INDICATE A WEAK
IMPULSE MOVING IN FROM THE WEST. QUESTION IS WILL IT BE STRONG
ENOUGH TO LIFT OUT THE CAP. MODEL GUIDANCE IS SUGGESTING SLIGHT
POPS. SO HAVE DECIDED TO SCALE BACK POPS FOR THURSDAY PROPER. LIKELY
POPS APPEARS GOOD FOR FRIDAY...INTO THE BEGINNING OF THE WEEKEND.
WILL TAPER POPS OFF QUICKLY SUNDAY AS A STRONG COLD FRONT CARRIES
LINGERING SHOWERS OFF TO OUR EAST. OTHERWISE EXPECT NEAR NORMAL
TEMPERATURES THROUGH FRIDAY. BUT SECOND MORE ORGANIZED SYSTEM THAT
BRINGS THE STRONG COLD FRONT THROUGH OUR AREA SATURDAY NIGHT...OR
EARLY SUNDAY MORNING WILL USHER IN ANOTHER ROUND OF MUCH COOLER AIR
TO THE AREA TO FINISH OUT THE LONG TERM PORTION OF THE FORECAST. A
SPECIAL NOTE THAT WITH HIGH PRESSURE CENTERED OVER OUR AREA MONDAY
AND TUESDAY MORNINGS...CLEAR SKIES AND LIGHT WINDS...WE WILL HAVE TO
KEEP AN EYE OUT FOR THE POTENTIAL FOR SOME PATCHY FROST AS OVERNIGHT
LOWS WILL PROBABLY BOTTOM OUT IN THE MID 30S IN OUR TYPICALLY COLDER
LOCATIONS BOTH MORNINGS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 133 AM EDT WED MAY 8 2013
A CHALLENGING AVIATION FORECAST THROUGH 13Z THIS MORNING.
OBSERVATIONS FROM AROUND EASTERN KENTUCKY HAVE BEEN INDICATING AREAS
OF FOG FORMING AROUND THE FORECAST AREA. THE FOG COULD BE LOCALLY
DENSE AT TIMES. AS FAR AS THE AIRPORTS GO...JKL HAS BEEN SOCKED IN
WITH LIFR FOG FOR THE PAST SEVERAL HOURS. LOZ AND SME...ON THE OTHER
HAND...HAVE YET TO EXPERIENCE FOG FORMATION. THE CURRENT THINKING IS
THAT JKL WILL LIKELY STAY SOCKED IN THROUGH 12Z BEFORE THE FOG LIFTS
AND DISSIPATES AFTER THE SUN IS UP. LOZ AND SME ARE MUCH LESS
CERTAIN. TYPICALLY SME GETS THEIR BEST FOG NIGHTS WHEN A LIGHT SOUTH
WIND BLOWS ACROSS LAKE CUMBERLAND AND CARRIES A GOOD FETCH OF
MOISTURE ACROSS THE SOMERSET AREA. AS OF TAF ISSUANCE...A LIGHT
WESTERLY WIND WAS BLOWING AT SME...SO CONDITIONS THERE WERE NOT
OPTIMAL FOR FOG. THEREFORE...WENT A BIT MORE OPTIMISTIC WITH THE
CONDITIONS AT SME OVERNIGHT THAN THE PREVIOUS FORECAST INDICATED.
DECIDED TO GO WITH MVFR VSBYS AND IFR CIGS AT SME. FOR LOZ...WENT A
BIT MORE PESSIMISTIC THAN SME...AS FOG CONDITIONS AT LOZ ARE MORE IN
LINE WITH TYPICAL FOG NIGHTS THAN AT SME. THAT BEING SAID...DECIDED
TO GO WITH IFR CONDITIONS AT LOZ FOR THE TIME PERIOD 9 TO 12Z...WITH
CONDITIONS RAPIDLY IMPROVING AFTER 12Z. EXPECTING SCATTERED TO
NUMEROUS RAIN SHOWERS AND ISOLATED THUNDERSTORMS TO AFFECT THE TAF
SITES BETWEEN 16 AND 23Z TODAY...AS AN AREA OF LOW PRESSURE SPINNING
OFF TO OUR EAST BECOMES ACTIVE DURING THE PEAK HEATING HOURS. SHOWERS
AND STORMS SHOULD DECREASE IN COVERAGE VERY QUICKLY AFTER 22Z
TODAY...ONCE THE LOW BEGINS TO PULL OFF TO THE EAST AND DAYTIME
HEATING IS LOST. MVFR CONDITIONS ARE EXPECTED WITH THE MORE INTENSE
RAIN SHOWERS AND ANY THUNDERSTORMS TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...HAL
LONG TERM...RAY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GRAY ME
645 AM EDT WED MAY 8 2013
.SYNOPSIS...
LOW PRESSURE WHICH HAS BEEN STALLED OVER THE SOUTH FOR THE LAST
WEEK WILL WEAKEN AND LIFT NORTH INTO OUR AREA TODAY INTO THURSDAY.
A STRONGER LOW MAY MOVE THROUGH LATER IN THE WEEKEND. A FRONT WILL
STALL OVER THE REGION THIS WEEKEND...WITH WAVES OF LOW PRESSURE
TRAVELING ALONG IT.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOW CLOUDS AND FOG ENTERING THE REGION FROM THE GULF OF MAINE WILL
BURN OFF THIS MORNING AND IS NOW IN SOUTHERN INTERIOR MAINE. THIS MOISTURE
MAY TAKE AN HOUR OR TWO LONGER THAN YESTERDAY TO MIX OUT.
MEANWHILE...CLOUDS WILL BEGIN TO INCREASE FROM SOUTH TO NORTH
TODAY AHEAD OF SLOW MOVING...AND WEAKENING CUTOFF LOW PRESSURE
SYSTEM. ENOUGH SUPPORT TO ADD LOW CHC POPS TO THE FCST FOR THE
AFTERNOON HOURS. LATEST HRRR RUN BRINGS A BAND OF SHOWERS INTO SW
NH AROUND 19 OR 20Z.
MAX TEMPS WILL ONCE AGAIN APPROACH 80 DEGRESS WELL IN TO THE
INTERIOR TODAY...WITH MAINLY 60S ALONG THE COAST. USED A BLEND OF
MAV/MET MOS NOS FOR AFTERNOON HIGHS.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AREAS OF FOG WILL REDEVELOP ONCE AGAIN TONIGHT. SOUTHERLY FLOW OFF
THE BRINK AS WELL AS THE APPROACH OF THE UPPER LEVEL TROUGH WILL
ALLOW FOR SCT SHOWER ACTIVITY OVER ALL PTNS OF ME/NH. PATCHY
DRIZZLE WILL BE PSBL ALG AND NEAR THE COASTLINE AS WELL.
THE PATTERN WILL REMAIN UNSETTLED ON THURSDAY AS THE UPPER TROUGH
SLOWLY ENTERS THE REGION. HIGHEST POS WILL BE IN THE MTNS OF MAINE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A SLOW MOVING FRONT WILL REMAIN BANKED UP TO OUR NORTHWEST
THURSDAY NIGHT. ALL MODELS CONTINUE TO SHOW A WEAK WAVE TRAVELING
ALONG THIS FEATURE...TRIGGERING MORE SCT SHOWERS ACROSS THE
REGION. THE FRONT BECOMES NEARLY STATIONARY OVER THE
WEEKEND...WITH DRIER AIR NOT ADVECTING INTO THE REGION UNTIL
SUNDAY.
THE FRONT WILL MOVE OFF THE COAST BY MONDAY...ALLOWING MUCH DRIER
AND COOLER AIR TO FINALLY ENTER THE REGION. GUSTY WINDS WILL
ACCOMPANY THE COLD AIR ADVECTION ON MONDAY. ANOTHER WEATHER
DISTURBANCE WILL BRING THE THREAT OF SHOWERS DURING THE MIDWEEK PERIOD.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...
CONDITIONS ARE EXPECTED TO BE IFR WITH LOCALLY LIFR IN FOG AND LOW
CLOUDS ALONG COASTAL AREAS AND JUST INLAND FROM THE COAST EARLY
THIS MORNING. THE FOG WILL BE MORE WIDESPREAD TONIGHT INTO THURSDAY.
LONG TERM...MVFR CONDITIONS ARE EXPECTED AT TAF SITES AS AN UPPER LOW
BRINGS SHOWERS TO THE REGION. SHOWERS WILL REDEVELOP ON FRIDAY
AHEAD OF A STRONG COLD FRONT. INSTABILITY SHOWERS WILL PERSIST
INTO THIS WEEKEND BEHIND THE COLD FRONT.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL BE BELOW SCA. PATCHY FOG IS
EXPECTED ACROSS THE WATERS TODAY WITH AREAS OF FOG TONIGHT INTO
THURSDAY.
LONG TERM...
WIND GUSTS WILL INCREASE FRIDAY AFTERNOON AS A COLD FRONT
APPROACHES NORTHERN NEW ENGLAND. NO HEADLINES ARE EXPECTED. WINDS
MAY BECOME GUSTY BEHIND A COLD FRONT EARLY NEXT WEEK.
&&
.FIRE WEATHER...
MORE HUMID AIR WILL CONTINUE TO FILTER INTO SOUTHERN AREAS TODAY.
HOWEVER...NORTHERN AREAS WILL CONTINUE TO BE DRY. CLOUDS WILL
INCREASE AND THICKEN LATER TODAY...ALLOWING SCATTERED SHOWERS TO
ENTER THE REGION. SCATTERED SHOWERS WILL CONTINUE RIGHT THROUGH
THE WEEKEND...WITH MORE WIDESPREAD SHOWER ACTIVITY POSSIBLE FRIDAY NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
344 AM EDT WED MAY 8 2013
.SYNOPSIS...
LOW PRESSURE WHICH HAS BEEN STALLED OVER THE SOUTH FOR THE LAST
WEEK WILL WEAKEN AND LIFT NORTH INTO OUR AREA TODAY INTO THURSDAY.
A STRONGER LOW MAY MOVE THROUGH LATER IN THE WEEKEND. A FRONT WILL
STALL OVER THE REGION THIS WEEKEND...WITH WAVES OF LOW PRESSURE
TRAVELING ALONG IT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW CLOUDS AND FOG ENTERING THE REGION FROM THE GULF OF MAINE WILL
BURN OFF THIS MORNING...HOWEVER...THIS MAY TAKE AN HOUR OR TWO
LONGER THAN YESTERDAY. MEANWHILE...CLOUDS WILL BEGIN TO INCREASE
FROM SOUTH TO NORTH TODAY AHEAD OF SLOW MOVING...AND WEAKENING
CUTOFF LOW PRESSURE SYSTEM. ENOUGH SUPPORT TO ADD LOW CHC POPS TO
THE FCST FOR THE AFTERNOON HOURS. LATEST HRRR RUN BRINGS A BAND OF
SHOWERS INTO SW NH AROUND 19 OR 20Z.
MAX TEMPS WILL ONCE AGAIN APPROACH 80 DEGRESS WELL IN TO THE
INTERIOR TODAY...WITH MAINLY 60S ALONG THE COAST. USED A BLEND OF
MAV/MET MOS NOS FOR AFTERNOON HIGHS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
AREAS OF FOG WILL REDEVELOP ONCE AGAIN TONIGHT. SOUTHERLY FLOW OFF
THE BRINK AS WELL AS THE APPROACH OF THE UPPER LEVEL TROUGH WILL
ALLOW FOR SCT SHOWER ACTIVITY OVER ALL PTNS OF ME/NH. PATCHY
DRIZZLE WILL BE PSBL ALG AND NEAR THE COASTLINE AS WELL.
THE PATTERN WILL REMAIN UNSETTLED ON THURSDAY AS THE UPPER TROUGH
SLOWLY ENTERS THE REGION. HIGHEST POS WILL BE IN THE MTNS OF MAINE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A SLOW MOVING FRONT WILL REMAIN BANKED UP TO OUR NORTHWEST
THURSDAY NIGHT. ALL MODELS CONTINUE TO SHOW A WEAK WAVE TRAVELING
ALONG THIS FEATURE...TRIGGERING MORE SCT SHOWERS ACROSS THE
REGION. THE FRONT BECOMES NEARLY STATIONARY OVER THE
WEEKEND...WITH DRIER AIR NOT ADVECTING INTO THE REGION UNTIL
SUNDAY.
THE FRONT WILL MOVE OFF THE COAST BY MONDAY...ALLOWING MUCH DRIER
AND COOLER AIR TO FINALLY ENTER THE REGION. GUSTY WINDS WILL
ACCOMPANY THE COLD AIR ADVECTION ON MONDAY. ANOTHER WEATHER
DISTURBANCE WILL BRING THE THREAT OF SHOWERS DURING THE MIDWEEK PERIOD.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...
CONDITIONS ARE EXPECTED TO BE IFR WITH LOCALLY LIFR IN FOG AND LOW
CLOUDS ALONG COASTAL AREAS AND JUST INLAND FROM THE COAST EARLY
THIS MORNING. THE FOG WILL BE MORE WIDESPREAD TONIGHT INTO THURSDAY.
LONG TERM...MVFR CONDITIONS ARE EXPECTED AT TAF SITES AS AN UPPER LOW
BRINGS SHOWERS TO THE REGION. SHOWERS WILL REDEVELOP ON FRIDAY
AHEAD OF A STRONG COLD FRONT. INSTABILITY SHOWERS WILL PERSIST
INTO THIS WEEKEND BEHIND THE COLD FRONT.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL BE BELOW SCA. PATCHY FOG IS
EXPECTED ACROSS THE WATERS TODAY WITH AREAS OF FOG TONIGHT INTO
THURSDAY.
LONG TERM...
WIND GUSTS WILL INCREASE FRIDAY AFTERNOON AS A COLD FRONT
APPROACHES NORTHERN NEW ENGLAND. NO HEADLINES ARE EXPECTED. WINDS
MAY BECOME GUSTY BEHIND A COLD FRONT EARLY NEXT WEEK.
&&
.FIRE WEATHER...
MORE HUMID AIR WILL CONTINUE TO FILTER INTO SOUTHERN AREAS TODAY.
HOWEVER...NORTHERN AREAS WILL CONTINUE TO BE DRY. CLOUDS WILL
INCREASE AND THICKEN LATER TODAY...ALLOWING SCATTERED SHOWERS TO
ENTER THE REGION. SCATTERED SHOWERS WILL CONTINUE RIGHT THROUGH
THE WEEKEND...WITH MORE WIDESPREAD SHOWER ACTIVITY POSSIBLE FRIDAY NIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
409 PM EDT WED MAY 8 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 408 PM EDT WED MAY 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS STILL SHOW BLOCKY FLOW
DOMINATING THE CONUS TO THE S OF PROGRESSIVE BUT GRADUALLY
AMPLIFYING FLOW ACROSS CANADA. IN THE BLOCKY CONUS FLOW...MID LEVEL
LOWS ARE LOCATED OVER THE SOUTHERN ROCKIES...ERN SD AND THE MID
ATLANTIC STATES. TO THE N...FLOW ACROSS CANADA HAS AMPLIFIED SOME IN
THE LAST COUPLE OF DAYS AS TROFFING IS NOSING S THRU MANITOBA/NRN
ONTARIO. MUCH STRONGER AMPLIFICATION WILL FOLLOW THIS WEEKEND AS
SHARP TROFFING DEVELOPS S INTO THE GREAT LAKES. COLD FRONT
ASSOCIATED WITH SHORTWAVE THAT MOVED FROM MANITOBA YESTERDAY TO
QUEBEC TODAY IS JUST NW AND N OF LAKE SUPERIOR. AHEAD OF THE
FRONT...IT HAS BEEN ANOTHER WARM DAY ACROSS UPPER MI. SOME LOCATIONS
ALONG LAKE SUPERIOR HAVE EXPERIENCED A MUCH WARMER DAY TODAY AS LAKE
BREEZE DID NOT DEVELOP AS EARLY AS IN PREVIOUS DAYS...AND IT IS
WEAKER. DESPITE ONSHORE WINDS ALONG LAKE MI...COOLING THERE HAS ONCE
AGAIN BEEN WEAK. INLAND...TEMPS HAVE SOARED THRU THE 70S WITH A FEW
SPOTS REACHING 80F. VERY DRY AIR STILL LINGERS OVER A GOOD PORTION
OF UPPER MI (NOTE THE VERY DRY COLUMN AGAIN SAMPLED BY THE 12Z KGRB
SOUNDING). AS A RESULT...DWPTS HAVE CRASHED DOWN AS LOW AS THE UPPER
20S/LWR 30S ACROSS PORTIONS OF MAINLY CNTRL/ERN UPPER MI. RH IS IN
THE 15-25PCT RANGE AT MOST LOCATIONS. FORTUNATELY...WINDS REMAIN
LIGHT...KEEPING FIRE WX CONCERNS IN CHECK FROM WHERE THEY COULD BE
ON A DAY LIKE THIS. SOME OF THE MID LEVEL MOISTURE NOTED ON PREVIOUS
DAYS SOUNDINGS FROM KINL/KMPX HAS ADVECTED INTO UPPER MI TODAY AND
MADE ITS PRESENCE KNOWN WITH POCKETS OF SCT/BKN MID CLOUDS EARLIER
IN THE DAY. DAYTIME HEATING HAS NOW LED TO VERY HIGH BASED CU
DEVELOPING OVER MUCH OF UPPER MI. A FEW RADAR RETURNS HAVE APPEARED
ON KMQT RADAR IMAGERY OVER WRN UPPER MI...BUT DRY LOW-LEVEL AIR HAS
PROBABLY PREVENTED ANY PCPN OR AT LEAST NOTHING MORE THAN A FEW
SPRINKLES FROM REACHING THE GROUND.
COLD FRONT TO THE N WILL DROP S...PASSING ACROSS UPPER MI
TONIGHT/EARLY THU MORNING. LOW-LEVEL DRY AIR WILL CONTINUE TO BE A
PROBLEM DUE TO LITTLE ADVECTION OF ANY MOISTURE AT THE LOW-LEVELS.
EVEN UPSTREAM...KINL/KMPX SOUNDINGS SHOW THAT LOW-LEVELS THERE HAVE
BEEN DRYING OUT OVER THE LAST DAY OR TWO...BUT THERE IS STILL
SUFFICIENT MOISTURE FOR SCT SHRA AND EVEN A FEW TSRA OVER NRN MN
INTO NW WI THIS AFTN. AS MID LEVEL LOW OVER ERN SD DRIFTS E...IT MAY
HELP PUSH BETTER MOISTURE INTO THE FRONTAL BOUNDARY THAT IS DROPPING
OVER THE AREA. HOWEVER...GIVEN THE LOW-LEVEL WIND FLOW/LACK OF
MOISTURE ADVECTION...PREFER THE GEM/ECMWF/UKMET AND TO SOME DEGREE
THE NAM IDEA OF MAINTAINING THE LOW-LEVEL DRY AIR OVER THE AREA
TONIGHT. AS A RESULT...WILL ONLY INCLUDE SCHC/LOW CHC POPS OVER THE
NW PORTION OF THE FCST AREA.
WITH MID LEVEL LOW OPENING UP/WEAKENING AS IT TRACKS E THU...IT
PROBABLY WON`T BE ABLE TO BRING A GOOD PUSH OF MOISTURE N OF THE
COLD FRONT THAT PASSED THRU THE AREA. HOWEVER...THERE ARE
INDICATIONS THAT MID LEVEL FGEN WILL INCREASE ACROSS THE UPPER
LAKES. WITH COLD FRONT SLIPPING S OF THE FCST AREA IN THE
MORNING...THERE WILL BE A BETTER OPPORTUNITY FOR LOW-LEVELS TO
MOISTEN IN THE COOLER AIR MASS UNDERNEATH THE FGEN FORCING...AND
THIS SHOULD PROVIDE AT LEAST A CHANCE OF SHRA OVER MUCH OF THE AREA
THU. WILL PAINT MAINLY THE WRN FCST AREA FOR BEST CHC OF SHRA AS
THERE ARE HINTS OF LOW-LEVEL DRY AIR STILL LINGERING OVER THE E.
WITH CAA AND MORE CLOUDS...IT WILL BE A COOLER DAY...ESPECIALLY NEAR
LAKE SUPERIOR DUE TO GRADIENT FLOW ACROSS THE LAKE (TEMPS ALONG THE
LAKE WILL PROBABLY ONLY BE IN THE LOW/MID 40S THRU THE DAY). ACROSS
THE SCNTRL AND E...TEMPS MAY STILL REACH THE MID 60S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT WED MAY 8 2013
UPPER FLOW GOES THROUGH A TRANSITION DURING THE LONG TERM PERIOD.
INITIALLY ON THURSDAY NIGHT FLOW IS MORE ZONAL WITH BROAD SHALLOW
TROUGH OVER MOST OF CANADA. LATER FRIDAY TRHOUGH SATURDAY...EXPECT
SHARP AMPLIFICATION AS TROUGH CURRENTLY NORTH OF ALASKA BARRELS
ACROSS CANADIAN PRAIRIES AND ONTARIO. PRIMARY COLD FRONT SWINGS
ACROSS UPPER MICHIGAN FRIDAY NIGHT INTO SATURDAY MORNING WITH
PARENT SFC LOW REACHING CENTRAL QUEBEC BY SUNDAY MORNING. MODELS
HAVE TRENDED FARTHER EAST WITH UPPER LOW CENTER AND QUICKER WITH
FRONTAL PASSAGE. TROUGH ALOFT SLOWLY MOVES INTO EASTERN CANADA ON
MONDAY WITH STRONG RIDGE AND WARM AIR EXPANDING TOWARD CENTRAL
CANADA AND THE PLAINS. TAIL END OF EXTENDED FEATURES WARMING TREND
OVER UPPER LAKES AS RIDGING MOVES FARTHER EAST. MAY SEE BREEZY
CONDITIONS ACCOMPANYING THE WARM UP AS STRONG LOW PRESSURE MOVES
FROM MANITOBA TO NORTHWEST ONTARIO.
SHALLOW COOL AIR SLOWLY FILTERS ACROSS UPR MICHIGAN LATER THURSDAY
AND THURSDAY EVENING. STILL A POTENTIAL OF RAIN THURSDAY EVENING
WITH LINGERING H7-H5 MOISTURE/LIFT DUE TO H7-H6 FRONTOGENESIS. NAM
AND GFS MORE BULLISH ON QPF OVER CWA COMPARED TO ECMWF AND GEM-NH.
THINKING NAM IDEA IS TOO FAR WEST WITH PRECIPITATION BAND...BUT
WILL KEEP SMALL POPS OVER SOUTH AND EAST THROUGH 03Z FRIDAY. REST
OF THURSDAY NIGHT INTO FRIDAY LOOKING QUIET OUT AHEAD OF THE STRONG
COLD FRONT. ONE CONCERN COULD BE STRONGER EAST-NORTHEAST WINDS OVER
EASTERN CWA THURSDAY NIGHT INTO FRIDAY MORNING...ESPECIALLY IF NOT
MUCH RAIN OCCURS THERE AND HUMIDITY RECOVERIES ARE POOR THURSDAY
NIGHT. GRADIENT WINDS DIMINISH THROUGH THE DAY ON FRIDAY...BUT AS
BUBBLE HIGH AT 1025MB BUILDS OVER LK SUPERIOR...NORTH WINDS COULD
STAY GUSTY INTO MID AFTN FROM COPPER HARBOR TO MARQUETTE AND GRAND
MARAIS. VERY DRY CONDITIONS AS H85 DWPNTS ARE DOWN TO AROUND -30C.
GIVEN SUCH DRY AIRMASS...EXPECT MIXED LAYER DWPNTS TO MIX OUT AWAY
FROM IMMEDIATE LK SUPERIOR SHORE AS LOW AS MID-UPPER TEENS IN THE
AFTN. EVEN WITH MUCH COOLER TEMPERATURES...ONLY AS WARM AS THE UPPER
50S INLAND...LOW DWPNTS WILL RESULT IN HUMIDITY VALUES BLO 25 PCT
IN AFTERNOON. BASED ON SOUNDINGS...DRY AIRMASS HANGS ON THROUGH
FRIDAY EVENING OVER ALL CWA.
FOCUS THEN IS ON STRONG COLD FRONTAL PASSAGE BY SATURDAY. 1000-500MB
THICKNESS PACKING FROM ECMWF/GFS/NAM INDICATE FRONTAL PASSAGE AFTER
MIDNIGHT FRIDAY NIGHT OVER FAR WEST CWA AND EARLY SATURDAY AFTERNOON
OVER THE FAR EASTERN CWA. SOUNDINGS SHOW MOISTURE BUILDING DOWN FROM
MID-LEVELS...RESULTING IN ONLY A FEW HOURS OF SATURATION FOR SOME
SHOWERS BEFORE DRYING AND SUBSIDENCE KICK IN BEFORE DAYBREAK OVER
WESTERN CWA AND BY MID MORNING OVER EASTERN CWA. WITH THE INITIAL
BATCH OF SHOWERS...LOOKS LIKE IT REMAINS TOO WARM BLO H9 TO HAVE
SNOW MIX IN WITH THE RAIN. 06Z NAM SHOWED ENOUGH COLD AIR WORKING
IN JUST AS PRECIP ENDED AT ERY FOR SOME SNOW SATURDAY MORNING. 12Z
RUN KEEPS IT ALL LIQUID. UNCERTAIN HOW MUCH MOISTURE IS AROUND ON
SATURDAY...BUT THAT WILL HAVE BEARING ON HOW MUCH PRECIP OCCURS AND
WHETHER THERE WILL BE ANY SNOW OR MIXED RAIN AND SNOW. THINKING THAT
NAM MAY BE OVERDONE WITH EXTENT OF SUBSIDENCE/DRYING OR AT THE LEAST
THE EXTENT/DURATION OF DRYING ON SATURDAY. GFS/ECMWF POINT TO CHANCE
OF MORE DIURNAL/COLD POOL TYPE SHOWERS AS TOTAL TOTALS PUSH 50 AND
WITH INCREASING H85-H7 RH. SHOULD SEE LOTS OF CLOUDS AND WILL GO
WITH LOW CHANCES FOR SHOWERS MOST AREAS. GIVEN ENOUGH MOISTURE AS
GFS/ECMWF INDICATE...WET BULB BLO ZERO THROUGH THE DEPTH OF THE
COLUMN WOULD SUPPORT AT LEAST A MIX OF RAIN AND SNOW OVER THE WEST
HALF. MAX TEMPS IN UPPER 30S TO LOWER 40S AT THE COOLEST WILL NOT
ALLOW FOR ANY APPRECIABLE SNOW ACCUMS THOUGH THERE COULD BE BRIEF
REDUCED VSBY IN THE HEAVIEST SNOW SHOWERS. OTHER ISSUE ON SATURDAY
WILL BE STRONG/GUSTY WINDS. SOUNDINGS INDICATE UNIDIRECTIONAL WNW
30-40 KT MIXED LAYER WINDS. PORTION OF THESE WINDS WILL MIX DOWN IN
GUSTS DUE TO MECHANICAL MIXING AND COLD AIR ADVECTION. EXPECT
STRONGEST WINDS OVER 40 MPH ON THE KEWEENAW PENINSULA...WITH GUSTS
OVER 30 MPH ELSEWHERE.
DRYING TREND TAKES OVER SUNDAY INTO MONDAY AS THE LARGER SCALE
TROUGH DEPARTS THE AREA. STILL COOL FOR SUNDAY WITH SIMILAR
READINGS TO SATURDAY. QUITE CHILLY SUNDAY NIGHT WITH MANY AREAS
FALLING BLO FREEZING WITH PWAT LESS THAN 50 PCT OF NORMAL AS SFC
HIGH PRESSURE RIDGE MOVES ACROSS.
REST OF EXTENDED FEATURES WARMING TREND AS RIDGE OVER PLAINS BUILDS
ACROSS. ELEVATED MOISTURE AND INSTABILITY WITH THE WARM AIR ADVECTION
MAY TRIGGER SCT SHOWERS/TSRA TUESDAY. CHANCES FOR WIDESPREAD PRECIP
SEEM LOW THOUGH AS PRIMARY LARGE SCALE LIFT STAYS OVER ONTARIO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 128 PM EDT WED MAY 8 2013
EXPECT VFR CONDITIONS THRU THE EVENING AT KIWD/KCMX/KSAW AS
LOW-LEVELS REMAIN VERY DRY. INCREASE IN MID LEVEL MOISTURE MAY YIELD
SOME HIGH BASED SHRA IN THE VCNTY OF KIWD THIS AFTN/TONIGHT AND AT
KCMX LATER TONIGHT. LATE TONIGHT INTO THU MORNING...STENGTHENING
CHILLY N/NE FLOW AND INCREASING POTENTIAL OF -SHRA MAY RESULT IN A
LOW STRATOCU/STRATUS DECK DEVELOPING AT KIWD/KCMX. NOT OUT OF THE
QUESTION THAT AN IFR CIG COULD DEVELOP AT KIWD WHERE WIND WILL HAVE
A BETTER UPSLOPE COMPONENT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT WED MAY 8 2013
LIGHT WINDS WILL PERSIST INTO THE EVENING. THEN...FOLLOWING THE
PASSAGE OF A COLD FRONT TONIGHT...NNE WINDS WILL INCREASE UP TO
15-25KT LATE TONIGHT THRU THU NIGHT. THE ARRIVAL OF ANOTHER HIGH
PRES RIDGE WILL THEN CAUSE WINDS TO DIMINISH FRI. A STRONGER COLD
FRONT WILL SLIDE ACROSS THE UPPER LAKES FRI NIGHT AND SHIFT WINDS TO
THE NW AT 20-30KT FOR SAT. GIVEN TIGHT PRES GRADIENT AND STRENGTH OF
CAA...GALE FORCE GUSTS WILL LIKELY OCCUR. WINDS WILL THEN DIMINISH W
TO E SUN AS HIGH PRES RIDGE ARRIVES. WINDS SHOULD BE UNDER 15KT
LATER SUN NIGHT THRU MON.
&&
.HYDROLOGY...
ISSUED AT 408 PM EDT WED MAY 8 2013
WARM TEMPS CONTINUE TO MELT LINGERING SN PACK OVER THE HIER TERRAIN
OF THE W AND NCENTRAL. RUNOFF INTO THE MONTREAL RIVER AND ISOLD
FLOODING ALONG THE WISCONSIN AND MICHIGAN BORDER IN WESTERN GOGEBIC
COUNTY NEAR IRONWOOD PROMPTED EVENING SHIFT ON TUESDAY TO ISSUE
AREAL FLOOD ADVISORY FOR GOGEBIC COUNTY. THIS MATCHES UP WITH FLOOD
ADVISORY OUT FOR IRON COUNTY WISCONSIN ISSUED BY WFO DULUTH. PLAN TO
LET WFO MARQUETTE ADVY EXPIRE AS SCHEDULED AS NO OTHER FLOODING HAS
BEEN REPORTED.
OTHERWISE...MOST AREA STREAMS/RIVERS CONTINUE TO REMAIN STEADY OR
SHOW SLOW DECLINE WITH RECENT DRY WX. WITH MINIMAL PRECIP IN THE
FORECAST IN THE COMING DAYS AND BULK OF SNOW PACK GONE EXCEPT OVER
THE HIGHER TERRAIN OF THE KEWEENAW/NCENTRAL...SUSPECT THESE TRENDS
WILL CONTINUE. RIVER ADVISORIES OR FLOOD WARNINGS CONTINUE FOR THE
TRAP ROCK RIVER AT LAKE LINDEN...THE STURGEON RIVER AT ALSTON AND
CHASSELL...AND THE MICHIGAMME RIVER AT WITCH LAKE AND REPUBLIC. FOR
COMPLETE DETAILS...SEE THE LATEST PRODCUTS FOR THESE RIVER FLOOD
WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...ROLFSON
HYDROLOGY...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
123 AM EDT WED MAY 8 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 403 PM EDT TUE MAY 7 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW BLOCKY FLOW
ACROSS THE CONUS TO THE S OF PROGRESSIVE FLOW ACROSS CNTRL CANADA. A
NARROW RIDGE EXTENDS FROM SRN BRITISH COLUMBIA/NRN WA E ACROSS THE
UPPER GREAT LAKES TO NEW ENGLAND. FARTHER S...CLOSED MID LEVEL LOWS
WERE LOCATED OVER CA/SRN NV...OVER SD AND OVER THE SE CONUS. WITH
THE UPPER GREAT LAKES STILL UNDER THE RIDGE...IT`S BEEN ANOTHER
PLEASANT EARLY MAY DAY ACROSS UPPER MI AS DEEP VERY DRY COLUMN (NOTE
12Z KGRB/KAPX SOUNDINGS) IS ALLOWING FOR ABUNDANT SUNSHINE. SOME
VERY HIGH BASED CU HAS DEVELOPED OVER THE W WITH A FEW ALONG THE
LAKE BREEZE BOUNDARY OVER THE E. VERY DEEP MIXING HAS INTO THE DRY
AIR ALOFT HAS RESULTED IN DWPTS CRASHING OVER THE LAST FEW HRS. RH
HAS PLUNGED INTO THE 10-20PCT RANGE AT A NUMBER OF LOCATIONS ACROSS
THE CNTRL AND E. LAKE BREEZES HAVE AGAIN DEVELOPED ACROSS THE
BOARD...AND WHILE IT`S CHILLY ALONG LAKE SUPERIOR WITH TEMPS IN THE
40S JUST LIKE YESTERDAY...THE COOLING IS AGAIN VERY WEAK ALONG MOST
OF THE LAKE MI SHORELINE. INLAND...TEMPS HAVE SOARED WELL INTO THE
70S.
NARROW RIDGE OVER THE UPPER LAKES IS IN THE PROCESS OF BREAKING DOWN
AS MODEST AMPLIFICATION OF THE FLOW IS UNDERWAY ACROSS CNTRL/ERN
CANADA IN ASSOCIATION WITH VIGOROUS SHORTWAVE MOVING ACROSS NRN
MANITOBA TO HUDSON BAY. MUCH STRONGER AMPLIFICATION WILL OCCUR LATER
THIS WEEK AS TROF SHARP TROF DEVELOPS S INTO THE GREAT LAKES. COLD
FRONT ASSOCIATED WITH NRN MANITOBA SHORTWAVE IS CURRENTLY RUNNING
FROM NRN MANITOBA TO MT. WITH FRONT STILL WELL W OF THE AREA THRU
THE NIGHT AND WITH DRY AIR MASS LINGERING...ANOTHER MAINLY CLEAR
NIGHT IS ANTICIPATED. OVERALL...LOW-LEVEL WINDS WILL BE LIGHT
AGAIN...AND THERE IS LITTLE CHANGE IN PRECIPITABLE WATER...
SUGGESTING MIN TEMPS SHOULD BE SIMILAR TO LAST NIGHT. HOWEVER...WITH
AIR MASS CONTINUING TO MODERATE WITH STRONG HEATING THIS AFTN...
WOULD EXPECT MINS GENERALLY TO BE A FEW DEGREES HIGHER THAN LAST
NIGHT. DEVELOPING LIGHT S TO SW FLOW WILL BEGIN TO STIR IN THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR...SO MINS THERE WILL PROBABLY BE
HIGHEST. MIN TEMPS SHOULD RANGE FROM THE 30S INLAND TO THE LWR 40S
ALONG LAKE SUPERIOR.
ON WED...APPROACHING COLD FRONT SHOULD REACH WRN/NRN LAKE SUPERIOR
LATE IN THE AFTN/EARLY EVE. SOME OF THE MOISTURE NOTED ON TODAYS 12Z
KMPX/KINL SOUNDINGS SHOULD ADVECT E AND NE AHEAD OF THE APPROACHING
COLD FRONT. HOWEVER...WITH LIGHT WINDS AND LITTLE ADVECTION AT THE
LOW-LEVELS...DRIER AIR WILL LIKELY LINGER UNDERNEATH THE MOISTENING
OCCURRING HIGHER UP. IN THE END...THIS WILL WORK TO MINIMIZE SHRA
THREAT WED. HOWEVER...WITH MLCAPE UPWARDS OF A FEW HUNDRED J/KG...
CAN`T RULE OUT A FEW HIGH BASED SHRA OVER THE W WHERE AFTN LAKE
BREEZE WILL HELP TO POOL LOW-LEVEL MOISTURE AND PROVIDE A LOW-LEVEL
FORCING MECHANISM. OTHERWISE...IT WILL BE ANOTHER WARM DAY ON PAR
WITH WHAT IS GOING ON THIS AFTN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 426 PM EDT TUE MAY 7 2013
WE WILL BEGIN WEDNESDAY NIGHT WITH A SERIES OF DISTURBANCES
SCATTERED ACROSS THE UNITED STATES. THE MAIN FEATURES INFLUENCING
OUR WEATHER OVER THE NEXT SEVERAL DAYS INCLUDE THE LARGE SCALE 500MB
TROUGH STRETCHED ACROSS MUCH OF CANADA...EXTENDING ACROSS MN/AND IA
AT 00Z THURSDAY...WITH AN ELONGATED SFC TROUGH SET UP FROM AROUND
IMT THROUGH ERY AND NORTHEASTWARD. THE TROUGH WILL CONTINUE TO SINK
SOUTHEAST OF THE CWA OVERNIGHT. THE NON-ECMWF SOLUTIONS CONTINUE TO
HIT THE NEXT SHORTWAVE A BIT HARDER...WITH 0.2-0.4IN OF QPF OVER
MUCH OF THE AREA. WILL CONTINUE THE HIGH CHANCE POPS...WITH A
CAVEAT. IF WE GET LESS PRECIP THAN ANTICIPATED...OR IT ENDS UP BEING
SLOWER...THE DOWNSLOPE AREAS FROM ESCANABA THROUGH MANISTIQUE...AND
EAST COULD BE QUITE A BIT LOWER /CURRENTLY FCST TO BOTTOM OUT 35-45
PERCENT/.
EXPECT THE SLOW MOTION 500MB TROUGH TO BE CENTERED OVER THE LAKE
SUPERIOR AND UPPER MI AT 00Z FRIDAY...WITH COOL HIGH PRESSURE
BUILDING IN AT THE SFC. 25-35KT 900-925MB WINDS ARE EXPECTED
THURSDAY NIGHT. THERE IS A SLIGHT CONCERN FOR FIRE CONCERNS...IF WE
HAVE POOR RH RECOVERIES...AS LOTS OF DRY AIR SLIDES IN FOR FRIDAY.
WENT WITH RH VALUES FALLING TO 25-35PERCENT...BUT WOULD NOT BE
SURPRISED TO SEE LOWER VALUES GIVEN THE VERY DRY AIR WITH MIXED
DEWPOINTS IN THE TEENS OR LOWER CENTRAL.
ZONAL FLOW WILL TAKE HOLD FRIDAY AFTERNOON/EVENING AHEAD OF YET
ANOTHER TROUGH ROTATING AROUND THE NORTHERN CANADIAN LOW. THIS ONE
LOOKS TO BE PARTICULARLY INTERESTING...AS IT INTENSIFIES INTO A
CLOSED LOW OVER EASTERN MANITOBA AND WESTERN ONTARIO FRIDAY NIGHT.
THERE IS SOME UNCERTAINTY TO THE POSITION OF THE 500MB LOW AT 00Z
SUNDAY...WHICH WILL LIKELY BE SOMEWHERE BETWEEN WESTERN UPPER MI TO
CENTRAL ONTARIO. THE 07/00Z ECMWF KEPT THE TREND OF BEING THE
DEEPEST WITH THE LOW...RUSHING COLD AIR IN FROM THE WEST DURING THE
DAY SATURDAY. KEPT A GOOD CHANCE OF MIXED PRECIP IN THE FCST FROM
SATURDAY THROUGH SUNDAY...WITH LITTLE TO NO REAL ACCUMULATION
EXPECTED AS THE BULK OF THE MOISTURE SHOULD BE EAST OF THE CWA BY
THE TIME THE -6 TO -10C AIR FILTERS IN. THE ECMWF REMAINS THE
COOLEST WITH THE SYSTEM.
FARTHER OUT...FEW CHANGES WERE MADE TO OUR MODERATING FCST FOR THE
START OF THE NEXT WORK WEEK...WITH W-SW WINDS AND DRY WX FIGURED
MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 122 AM EDT WED MAY 8 2013
EXPECT VFR CONDITIONS AND LIGHT WINDS AT ALL 3 SITES TONIGHT INTO WED
MORNING WITH DRY HI PRES DOMINATING. APPROACHING COLD FRONT FM SRN
CANADA COULD BRING AN INCREASE IN MID CLOUDS LATE WED AFTERNOON INTO
WED EVENING IN ITS WAKE BUT OTHERWISE VFR CONDITIONS WILL PREVAIL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 PM EDT TUE MAY 7 2013
HIGH PRESSURE WILL CONTINUE TO PRODUCE LIGHT WINDS THRU WED...
BUT A COLD FRONT MOVING ACROSS LAKE SUPERIOR LATE WED AFTN AND
EVENING WILL LEAD TO INCREASING NORTH-NORTHEAST WINDS PEAKING IN THE
15-25KT RANGE WED NIGHT INTO THU MORNING. HIGH PRESSURE WILL BUILD
BACK OVER THE AREA FOR FRI AND DIMINISH THE WINDS. A STRONGER
COLD FRONT WILL SLIDE ACROSS THE UPPER LAKES FRI NIGHT AND SHIFT
WINDS TO THE NW AT 20-30KTS SAT. THESE STRONGER WINDS WILL CONTINUE
INTO SAT NIGHT BEFORE GRADUALLY DIMINISHING FROM W TO E ON SUN.
&&
.HYDROLOGY...
ISSUED AT 426 PM EDT TUE MAY 7 2013
WE WILL MONITOR LOCAL RIVER LEVELS...BUT CONTINUE TO SEE FALLING
VALUES ACROSS MUCH OF THE REGION AS THE SNOW PACK FALLS TO NEAR ZERO
WITH OUR SERIES OF ABOVE NORMAL TEMPERATURES.
THE LATEST SNOW DEPTH OBSERVATIONS /FROM EARLIER THIS MORNING AROUND
8AM HAS IRONWOOD WITH NO SNOW LEFT ON THE GROUND...AND ATLANTIC MINE
WITH 4IN. A FEW POCKETS OF HIGHER AMOUNTS ARE LIKELY ACROSS THE
KEWEENAW...AND THE HIGHEST ELEVATIONS OF NORTHERN MARQUETTE COUNTY.
THE TRICKY LINGERING ISSUES AT AT TRRM4 /TRAP ROCK - LAKE LINDEN/
AND BESM4 /BESSEMER - BLACK RIVER/. FOR COMPLETE DETAILS...SEE THE
LATEST RIVER FLOOD WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...ROLFSON
HYDROLOGY...KF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1252 PM CDT WED MAY 8 2013
.UPDATE...
ISSUED AT 1252 PM CDT WED MAY 8 2013
MADE MINOR UPDATES TO GRIDS FOR ACTIVITY THAT IS DIMINISHING AS IT
GETS CLOSER TO FORECAST AREA. WILL SEE SOME SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS THIS AFTERNOON AS DECAYING MCV SLIDES
THROUGH REGION...WITH MOST OF ACTIVITY ALONG AND SOUTH OF I-70.
STILL EXPECT HIGHS IN THE UPPER 70S TO LOW 80S.
BYRD
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 329 AM CDT WED MAY 8 2013
LITTLE CHANGE IN THINKING THIS MORNING SINCE PREVIOUS FORECAST. THE
PRIMARY CHALLENGE THIS MORNING IS TIMING THE START OF PRECIP TODAY.
IF CURRENT RADAR TRENDS HOLD TRUE...THE SHOWERS CURRENTLY OVER
KANSAS WILL REACH THE WESTERN-MOST PORTIONS OF OUR CWFA BETWEEN
16-17Z. THIS TIMING AGREES WELL WITH MOST SHORT RANGE MODEL
GUIDANCE INCLUDING THE HRRR AND 4KM NCEP WRF. SHOULD SEE INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHEAST
MISSOURI TONIGHT AS THE COMPACT SHORTWAVE OVER SOUTH DAKOTA DRIFTS
SOUTHEAST INTO IOWA. THIS FORCES THE LOW LEVEL JET TO STRENGTHEN
OVER THE AREA CAUSING AMPLE LOW LEVEL MOISTURE CONVERGENCE OVER
REGION WHICH SHOULD KEEP PRECIPITATION GOING OVER CENTRAL AND
NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS FOR MUCH OF THE
NIGHT.
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS THE REST OF THE
AREA ON THURSDAY AS DAYTIME HEATING DESTABILIZES THE ATMOSPHERE AND
THE SHORTWAVE CONTINUES TO DIG INTO THE MID-MISSISSIPPI VALLEY.
STRONG STORMS ARE POSSIBLE...THO CONDITIONS APPEAR MARGINAL FOR
SEVERE WITH 1000-1200 J/KG CAPE BUT ONLY 15-20KTS OF SHEAR. IF
THERE ARE SEVERE STORMS WOULD THINK THE PRIMARY THREAT WILL BE
DAMAGING WINDS...HAIL THREAT SEEMS LIMITED DUE TO SMALL CAPE VALUES
IN THE HAIL GROWTH ZONE.
SHOULD SEE PRECIP DECREASE FROM NORTHWEST TO SOUTHEAST LATE THURSDAY
NIGHT INTO THE PRE-DAWN HOURS OF FRIDAY MORNING. CANNOT RULE OUT
SCATTERED SHOWERS AND THUNDERSTORMS GENERALLY ALONG AND SOUTH OF
I-70 AGAIN FRIDAY...BUT THINK THE THREAT FOR ORGANIZED CONVECTION
WILL BE MINIMAL. TEMPERATURE TRENDS THROUGH FRIDAY WILL BE HIGHLY
DEPENDENT ON PRECIPITATION. GENERALLY STUCK PRETTY CLOSE TO THE
MIDDLE OF THE ROAD OF GUIDANCE NUMBERS.
CARNEY
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED MAY 8 2013
GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH THE SATURDAY THROUGH
MONDAY PERIOD. ANOTHER SHORTWAVE WILL DIG SOUTHEAST OUT OF
CANADA INTO THE GREAT LAKES REGION AMPLIFYING THE FLOW ACROSS THE
U.S. THIS WILL PUSH A COLD FRONT SOUTH THROUGH THE MISSISSIPPI
VALLEY ON SATURDAY. A STRONG CANADIAN HIGH WILL DROP INTO THE ARE
BEHIND THE FRONT BRINGING US ANOTHER SHOT OF BELOW NORMAL
TEMPERATURES. GFS AND ECMWF CONTINUE TO PRODUCE VERY LIGHT QPF
ACROSS PARTS OF THE AREA ON SATURDAY AS THE FRONT MOVES THROUGH SO
HAVE KEPT CHANCE POPS IN THE FORECAST. 850MB TEMPS DROP TO NEAR
ZERO SUNDAY SO HAVE CONTINUED THE DOWNWARD TREND FOR
HIGHS...UNDERCUTTING GUIDANCE BY A FEW DEGREES. MONDAY MORNING WILL
LIKELY BE THE COLDEST OF THE BUNCH...WITH POSSIBLY THE LAST FROST OF
THE SEASON. SHOULD SEE A NICE WARM UP MONDAY AFTERNOON AND TUESDAY
AS AN UPPER LEVEL RIDGE BUILDS OVERHEAD AND SOUTHWEST FLOW RETURNS
TO THE AREA.
CARNEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1252 PM CDT WED MAY 8 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE CONTINUING TO
TRACK TO THE EAST EARLY THIS AFTERNOON. STILL HARD TO SAY IF
ACTIVITY WILL HOLD TOGETHER LONG ENOUGH TO AFFECT TAF SITES...SO
JUST KEPT VCNTY SHOWER MENTION AT THIS TIME BEFORE TAPERING OFF BY
00Z THURSDAY. OTHERWISE...WINDS TO PERSIST FROM THE SOUTH WITH VFR
CIGS THROUGH THE FORECAST PERIOD. BETTER CHANCES OF STORMS WITH
MAIN FRONT OVER NORTHEAST MO/WEST CENTRAL IL...SO HAVE TRWS MOVING
INTO KUIN BY 07Z THURSDAY. NOT SURE HOW FAR SOUTH THEY WILL GET
FOR TAF SITES ALONG I-70 CORRIDOR SO JUST HAVE VCNTY
SHOWERS/THUNDERSTORMS FROM MID MORNING ON DURING THE DAY THURSDAY.
SPECIFICS FOR KSTL...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ARE CONTINUING TO TRACK TO THE EAST EARLY THIS AFTERNOON. STILL
HARD TO SAY IF ACTIVITY WILL HOLD TOGETHER LONG ENOUGH TO AFFECT
METRO AREA...SO JUST KEPT VCNTY SHOWER MENTION BEGINNING AT 22Z
WEDNESDAY TAPERING OFF BY 00Z THURSDAY. OTHERWISE...WINDS TO
PERSIST FROM THE SOUTH WITH VFR CIGS THROUGH THE FORECAST PERIOD.
BETTER CHANCES OF STORMS WITH MAIN FRONT OVER NORTHEAST MO/WEST
CENTRAL IL...OVERNIGHT THROUGH THURSDAY. NOT SURE HOW FAR SOUTH
THEY WILL GET FOR METRO AREA SO JUST HAVE VCNTY SHOWERS BEGINNING
AROUND 13Z THURSDAY AND VCNTY THUNDERSTORMS AFTER 21Z THURSDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
616 AM CDT WED MAY 8 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 329 AM CDT WED MAY 8 2013
LITTLE CHANGE IN THINKING THIS MORNING SINCE PREVIOUS FORECAST. THE
PRIMARY CHALLENGE THIS MORNING IS TIMING THE START OF PRECIP TODAY.
IF CURRENT RADAR TRENDS HOLD TRUE...THE SHOWERS CURRENTLY OVER
KANSAS WILL REACH THE WESTERN-MOST PORTIONS OF OUR CWFA BETWEEN
16-17Z. THIS TIMING AGREES WELL WITH MOST SHORT RANGE MODEL
GUIDANCE INCLUDING THE HRRR AND 4KM NCEP WRF. SHOULD SEE INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHEAST
MISSOURI TONIGHT AS THE COMPACT SHORTWAVE OVER SOUTH DAKOTA DRIFTS
SOUTHEAST INTO IOWA. THIS FORCES THE LOW LEVEL JET TO STRENGTHEN
OVER THE AREA CAUSING AMPLE LOW LEVEL MOISTURE CONVERGENCE OVER
REGION WHICH SHOULD KEEP PRECIPITATION GOING OVER CENTRAL AND
NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS FOR MUCH OF THE
NIGHT.
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS THE REST OF THE
AREA ON THURSDAY AS DAYTIME HEATING DESTABILIZES THE ATMOSPHERE AND
THE SHORTWAVE CONTINUES TO DIG INTO THE MID-MISSISSIPPI VALLEY.
STRONG STORMS ARE POSSIBLE...THO CONDITIONS APPEAR MARGINAL FOR
SEVERE WITH 1000-1200 J/KG CAPE BUT ONLY 15-20KTS OF SHEAR. IF
THERE ARE SEVERE STORMS WOULD THINK THE PRIMARY THREAT WILL BE
DAMAGING WINDS...HAIL THREAT SEEMS LIMITED DUE TO SMALL CAPE VALUES
IN THE HAIL GROWTH ZONE.
SHOULD SEE PRECIP DECREASE FROM NORTHWEST TO SOUTHEAST LATE THURSDAY
NIGHT INTO THE PRE-DAWN HOURS OF FRIDAY MORNING. CANNOT RULE OUT
SCATTERED SHOWERS AND THUNDERSTORMS GENERALLY ALONG AND SOUTH OF
I-70 AGAIN FRIDAY...BUT THINK THE THREAT FOR ORGANIZED CONVECTION
WILL BE MINIMAL. TEMPERATURE TRENDS THROUGH FRIDAY WILL BE HIGHLY
DEPENDENT ON PRECIPITATION. GENERALLY STUCK PRETTY CLOSE TO THE
MIDDLE OF THE ROAD OF GUIDANCE NUMBERS.
CARNEY
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED MAY 8 2013
GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH THE SATURDAY THROUGH
MONDAY PERIOD. ANOTHER SHORTWAVE WILL DIG SOUTHEAST OUT OF
CANADA INTO THE GREAT LAKES REGION AMPLIFYING THE FLOW ACROSS THE
U.S. THIS WILL PUSH A COLD FRONT SOUTH THROUGH THE MISSISSIPPI
VALLEY ON SATURDAY. A STRONG CANADIAN HIGH WILL DROP INTO THE ARE
BEHIND THE FRONT BRINGING US ANOTHER SHOT OF BELOW NORMAL
TEMPERATURES. GFS AND ECMWF CONTINUE TO PRODUCE VERY LIGHT QPF
ACROSS PARTS OF THE AREA ON SATURDAY AS THE FRONT MOVES THROUGH SO
HAVE KEPT CHANCE POPS IN THE FORECAST. 850MB TEMPS DROP TO NEAR
ZERO SUNDAY SO HAVE CONTINUED THE DOWNWARD TREND FOR
HIGHS...UNDERCUTTING GUIDANCE BY A FEW DEGREES. MONDAY MORNING WILL
LIKELY BE THE COLDEST OF THE BUNCH...WITH POSSIBLY THE LAST FROST OF
THE SEASON. SHOULD SEE A NICE WARM UP MONDAY AFTERNOON AND TUESDAY
AS AN UPPER LEVEL RIDGE BUILDS OVERHEAD AND SOUTHWEST FLOW RETURNS
TO THE AREA.
CARNEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 604 AM CDT WED MAY 8 2013
OTHER THAN SOME LOW LYING FOG AT KSUS AND KCPS THIS MORNING
CONDITIONS REMAINED VFR OVERNIGHT. AREA OF RAIN AND THUNDERSTORMS
OVER KANSAS WILL WEAKEN SIGNIFICANTLY AS IT MOVES EAST...WITH
PERHAPS A SHOWER OR SPRINKLE AFFECTING THE TERMINALS THIS
AFTERNOON. OTHERWISE...THE BETTER CHANCE OF RAIN AND THUNDERSTORMS
WILL WAIT UNTIL OVERNIGHT ACROSS NORTHERN MISSOURI AND WEST
CENTRAL ILLINOIS AND THURSDAY MORNING AT THE REMAINING TERMINALS.
LIGHT WIND WILL BECOME SOUTHERLY TODAY...AND THEN BACK TO THE
EAST-SOUTHEAST FROM OUTFLOW OF CONVECTION EITHER OVERNIGHT OR
THURSDAY MORNING.
SPECIFICS FOR KSTL...
INCREASING HIGH CLOUD COVER TODAY WITH A WEAKENING LINE OF SHOWERS
EXPECTED TO MOVE ACROSS THE TERMINAL LATE THIS AFTERNOON. BETTER
CHANCE OF RAIN HOLDS OFF UNTIL EITHER LATE TONIGHT OR THURSDAY.
LIGHT WIND TO BECOME SOUTHERLY.
CVKING
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 83 62 78 60 / 10 40 60 60
QUINCY 78 59 73 54 / 40 80 80 60
COLUMBIA 78 59 74 57 / 40 80 70 60
JEFFERSON CITY 79 60 75 58 / 40 70 60 60
SALEM 79 58 78 61 / 10 10 60 60
FARMINGTON 79 59 77 59 / 20 20 50 60
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
331 AM CDT WED MAY 8 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 329 AM CDT WED MAY 8 2013
LITTLE CHANGE IN THINKING THIS MORNING SINCE PREVIOUS FORECAST. THE
PRIMARY CHALLENGE THIS MORNING IS TIMING THE START OF PRECIP TODAY.
IF CURRENT RADAR TRENDS HOLD TRUE...THE SHOWERS CURRENTLY OVER
KANSAS WILL REACH THE WESTERN-MOST PORTIONS OF OUR CWFA BETWEEN
16-17Z. THIS TIMING AGREES WELL WITH MOST SHORT RANGE MODEL
GUIDANCE INCLUDING THE HRRR AND 4KM NCEP WRF. SHOULD SEE INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTHEAST
MISSOURI TONIGHT AS THE COMPACT SHORTWAVE OVER SOUTH DAKOTA DRIFTS
SOUTHEAST INTO IOWA. THIS FORCES THE LOW LEVEL JET TO STRENGTHEN
OVER THE AREA CAUSING AMPLE LOW LEVEL MOISTURE CONVERGENCE OVER
REGION WHICH SHOULD KEEP PRECIPITATION GOING OVER CENTRAL AND
NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS FOR MUCH OF THE
NIGHT.
THUNDERSTORM COVERAGE IS EXPECTED TO INCREASE ACROSS THE REST OF THE
AREA ON THURSDAY AS DAYTIME HEATING DESTABILIZES THE ATMOSPHERE AND
THE SHORTWAVE CONTINUES TO DIG INTO THE MID-MISSISSIPPI VALLEY.
STRONG STORMS ARE POSSIBLE...THO CONDITIONS APPEAR MARGINAL FOR
SEVERE WITH 1000-1200 J/KG CAPE BUT ONLY 15-20KTS OF SHEAR. IF
THERE ARE SEVERE STORMS WOULD THINK THE PRIMARY THREAT WILL BE
DAMAGING WINDS...HAIL THREAT SEEMS LIMITED DUE TO SMALL CAPE VALUES
IN THE HAIL GROWTH ZONE.
SHOULD SEE PRECIP DECREASE FROM NORTHWEST TO SOUTHEAST LATE THURSDAY
NIGHT INTO THE PRE-DAWN HOURS OF FRIDAY MORNING. CANNOT RULE OUT
SCATTERED SHOWERS AND THUNDERSTORMS GENERALLY ALONG AND SOUTH OF
I-70 AGAIN FRIDAY...BUT THINK THE THREAT FOR ORGANIZED CONVECTION
WILL BE MINIMAL. TEMPERATURE TRENDS THROUGH FRIDAY WILL BE HIGHLY
DEPENDENT ON PRECIPITATION. GENERALLY STUCK PRETTY CLOSE TO THE
MIDDLE OF THE ROAD OF GUIDANCE NUMBERS.
CARNEY
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED MAY 8 2013
GUIDANCE CONTINUES TO BE VERY CONSISTENT WITH THE SATURDAY THROUGH
MONDAY PERIOD. ANOTHER SHORTWAVE WILL DIG SOUTHEAST OUT OF
CANADA INTO THE GREAT LAKES REGION AMPLIFYING THE FLOW ACROSS THE
U.S. THIS WILL PUSH A COLD FRONT SOUTH THROUGH THE MISSISSIPPI
VALLEY ON SATURDAY. A STRONG CANADIAN HIGH WILL DROP INTO THE ARE
BEHIND THE FRONT BRINGING US ANOTHER SHOT OF BELOW NORMAL
TEMPERATURES. GFS AND ECMWF CONTINUE TO PRODUCE VERY LIGHT QPF
ACROSS PARTS OF THE AREA ON SATURDAY AS THE FRONT MOVES THROUGH SO
HAVE KEPT CHANCE POPS IN THE FORECAST. 850MB TEMPS DROP TO NEAR
ZERO SUNDAY SO HAVE CONTINUED THE DOWNWARD TREND FOR
HIGHS...UNDERCUTTING GUIDANCE BY A FEW DEGREES. MONDAY MORNING WILL
LIKELY BE THE COLDEST OF THE BUNCH...WITH POSSIBLY THE LAST FROST OF
THE SEASON. SHOULD SEE A NICE WARM UP MONDAY AFTERNOON AND TUESDAY
AS AN UPPER LEVEL RIDGE BUILDS OVERHEAD AND SOUTHWEST FLOW RETURNS
TO THE AREA.
CARNEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1155 PM CDT TUE MAY 7 2013
HAVE ADDED AREAS OF MVFR FOG TO STL AREA TAFS DUE TO NARROWING
TEMP/DEWPOINT SPREADS...WITH TEMPO IFR VSBYS AT FOG PRONE SUS AND CPS.
ELSEWHERE...AMS IS MUCH DRIER SO NOT EXPECTING MUCH OF A FOG THREAT....
AND AS SURFACE RIDGE WORKS ACROSS AREA CLEAR SKIES AND LIGHT
WINDS WILL PREVAIL. WE COULD SEE A BIT OF DIURNALLY DRIVEN CU POP
AT MID MORNING...BUT PRIMARY CLOUDINESS ON WEDNESDAY SHOULD BE MID
AND HIGH LEVEL CLOUDS THAT WILL SLOWLY WORK FROM WEST TO EAST
ACROSS THE AREA. STILL BELIEVE THAT SIGNIFICANT PRECIP WILL HAVE A
HARD TIME MAKING TOO MUCH EWD PROGRESS...SO FOR THIS SET HAVE
CONTINUED WITH THE IDEA OF VCSH FROM A MID CLOUD DECK WORKING INTO
UIN AND COU BY MID AFTERNOON...AND INTO THE STL AREA BY MID EVENING.
SPECIFICS FOR KSTL...HAVE ADDED MVFR FOG AT STL DUE TO NARROWING
TEMP/DEWPOINT SPREADS...BUT THINK THAT THE LOWER IFR VSBYS WILL BE
CONFINED TO RIVER VALLEY LOCATIONS. OTHERWISE...LOOKING FOR CLEAR
SKIES OVERNIGHT....GIVING WAY TO A BIT OF CU BY MID MORNING AND
THEN A SLOW INCREASE OF MID AND HIGH LEVEL VFR CLOUDS. AS
MENTIONED ABOVE...THINK PRECIP WILL BE SOMEWHAT SLOW TO SPREAD
EAST...TO HAVE ADDED VCSH FROM VFR MID CLOUD DECK BY WEDNESDAY EVENING.
TRUETT
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 83 62 78 60 / 10 40 60 60
QUINCY 78 59 73 54 / 40 80 80 60
COLUMBIA 78 59 74 57 / 40 80 70 60
JEFFERSON CITY 79 60 75 58 / 40 70 60 60
SALEM 79 58 78 61 / 10 10 60 60
FARMINGTON 79 59 77 59 / 20 20 50 60
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
658 PM CDT THU MAY 9 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
A FEW LIGHT SHOWERS WILL CONTINUE TO WRAP AROUND THE
SURFACE LOW ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY THROUGH THE
LATE AFTERNOON HOURS...AS IT CONTINUES TO TRANSITION FURTHER
EASTWARD. STILL CANNOT RULE OUT THE SLIGHT POSSIBILITY OF A
THUNDERSTORM OR TWO...MAINLY ACROSS PORTIONS OF NORTH CENTRAL
KANSAS...AS MESO ANALYSIS PAGE FROM SPC IS INDICATION SOME WEAK
INSTABILITY PERSISTING ACROSS THIS AREA. LATEST WRF ACTUALLY
HANGS ONTO SOME SCATTERED SHOWER ACTIVITY THROUGH THE OVERNIGHT
HOURS...BUT THIS MODEL SEEMS TO BE THE OUTLIER...SO HAVE NO MORE
THAN A FEW SPRINKLES IN THE FORECAST AFTER 00Z.
THEREAFTER...EXPECT A SURFACE RIDGE OF HIGH PRESSURE TO SLIDE
ACROSS THE FORECAST AREA FROM THE WEST OVERNIGHT...AND WITH THE
ANTICIPATED LIGHT WINDS...PARTIAL CLEARING...AND ELEVATED DEW
POINTS...EXPECT SOME FOG DEVELOPMENT OVERNIGHT. LATEST HRRR IS
HINTING AT DENSE FOG FORMING ALONG THE SPINE OF THE RIDGE AXIS
AFTER MIDNIGHT...BUT WITH SOME UNCERTAINTY STILL...ONLY REDUCED
VISIBILITIES TO 1 MILE ACROSS THE FORECAST AREA DURING THE LATE
OVERNIGHT HOURS THROUGH EARLY FRIDAY MORNING...AND HELD OFF ON
ISSUING A DENSE FOG ADVISORY FOR THE TIME BEING.
AFTER THE FOG BURNS OFF FRIDAY MORNING...EXPECT A FAIRLY NICE AND
SEASONAL DAY ACROSS THE REGION...AS THE SURFACE RIDGE WILL BE SLOW
TO PUSH EAST RESULTING IN GENERALLY LIGHT WINDS DURING THE
AFTERNOON HOURS. WITH CLEARING SKIES...RECOVERING TEMPERATURES
ALOFT...AND GOOD MIXING ANTICIPATED...EXPECT TEMPERATURES TO
RETURN TO NEAR CLIMATOLOGICAL NORMS...GENERALLY IN THE LOWER 70S
AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
REALLY NO SIGNIFICANT CHANGES FOR THE FIRST PORTION OF THE LONG TERM
PERIOD...FRIDAY NIGHT THROUGH THE DAY SATURDAY. MODELS REMAIN IN
PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN...SHOWING FRIDAY
EVENING UNDER SHARP NORTHWESTERLY FLOW...A RESULT OF A TROUGH AXIS
PUSHING EAST OF THE CWA...AND RIDGING POKING INTO THE CENTRAL/NRN
WEST COAST...NORTH OF CUT OFF LOW OVER THE NM/AZ/MEX BORDER AREA.
FOCUS TURNS TO AN UPPER LEVEL LOW PRESSURE SYSTEM OVER CENTRAL
CANADA...WHICH IS EXPECTED TO SLIDE SOUTHEAST OVERNIGHT AND BY
SATURDAY MORNING IS REACHING INTO THE WRN GREAT LAKES AREA. THE
ACCOMPANYING TROUGH AXIS WILL EXTEND TO THE SOUTH AND SWING THROUGH
THE CENTRAL PLAINS PRIMARILY FRIDAY NIGHT...AND KEPT THE MENTION OF
SPRINKLES GOING ACROSS THE NRN HALF OF THE CWA. WITH THE BRUNT OF
THE LIFT WELL NE OF THE CWA...AND FORECAST SOUNDINGS CONTINUING TO
SHOW DRIER AIR IN THE AREA...DIDNT WANT TO INSERT ANY MEASURABLE
PRECIP AT THIS POINT. THE TIMING OF THE SFC COLD FRONT PUSHED
THROUGH THE CWA BY THIS DISTURBANCE HASNT CHANGED MUCH WITH THE
LATEST MODEL RUNS...AND BY 12Z SATURDAY LOOKS TO HAVE PUSHED THROUGH
TO AT LEAST THE NE/KS STATE LINE...AND EVEN A LITTLE FURTHER SOUTH
VIA THE NAM/SREF. THROUGH THE DAYTIME HOURS ON SATURDAY...SHOULD
SEE DECREASING CLOUD COVER...AND EXPECTING WINDS TO BE ON THE GUSTY
SIDE THROUGH AT LEAST THE FIRST HALF OF THE DAY...BUT SHOULD
DIMINISH ESP BY LATE AFTERNOON AS SFC HIGH PRESSURE BUILDS IN FROM
THE NORTH. THE COOLER AIRMASS ACCOMPANYING THIS FRONT IS EXPECTED
TO BRING A DROP IN HIGHS...BUT STILL EXPECTING TO REACH INTO THE
60S.
FOR SATURDAY NIGHT AND SUNDAY...MAIN CHANGE MADE TO THIS TIME FRAME
WAS TO ADD POPS TO THE FORECAST. YESTERDAY THERE WAS JUST A HINT AT
THE POSSIBILITY OF THE ACTIVITY DEVELOPING ALONG THE HIGH PLAINS
/DRIVEN BY UPSLOPE FLOW AND A WEAK MID LEVEL DISTURBANCE/ SATURDAY
AFTERNOON SLIDING SOUTHEAST AND AFFECTING AT LEAST PORTIONS OF THE
CWA...BUT NOW THE 12Z RUNS OF THE OPERATIONAL MODELS HAVE TRENDED
THIS WAY. ADDED SOME SLIGHT CHANCE AND CHANCE POPS FOR NOW...STILL
SOME SLIGHT VARIATIONS WITH TIMING/LOCATIONS...BUT MOST DO SHOW
ACTIVITY LINGERING INTO THE 12-18Z PERIOD SUNDAY. INSTABILITY IS
PRETTY PATHETIC...MUCAPE VALUES OF ARND 100 J/KG...SO WHILE AN
ISOLATED RUMBLE OF THUNDER OR TWO ARE POSSIBLE...NOT EXPECTING
WIDESPREAD THUNDERSTORMS. DEPENDING ON THE SPEED THIS ACTIVITY
EXISTS...THE HIGHS FOR THE DAY MAY NEED SOME ADJUSTMENT. TRENDED
HIGHS BACK JUST A DEGREE OR TWO OVERALL...BUT IF THINGS LINGER
LONGER THAN CURRENTLY EXPECTED...TEMPS WILL LIKELY STRUGGLE TO REACH
WHAT IS FORECAST /MID 60S TO NEAR 70/.
MONDAY AND TUESDAY...HERE COMES THE WARM UP. PAST FEW RUNS OF THE
MODELS HAVE BEEN PRETTY CONSISTENT WITH THE PATTERN ACROSS THE
CONUS...AT 12Z MONDAY THE CWA IS STILL SITTING UNDER NORTHWESTERLY
FLOW...AS THE CUT OFF LOW CONTINUES TO SIT OVER NRN MEX...AND
RIDGING ORIGINATING OFF THE WEST COAST IS EXTENDED INTO THE
ROCKIES. BY THE END OF THE DAYTIME HRS ON MONDAY AXIS LOOKS TO HAVE
SHIFTED FURTHER EAST INTO THE ROCKIES. WARMER AIR ACCOMPANYING THIS
RIDGE WILL BRING A BUMP UP IN TEMPS MONDAY...AND AGAIN TUESDAY AS
THE CWA REMAINS UNDER ITS INFLUENCE. HIGHS ON MONDAY CURRENTLY
FORECAST TO REACH THE UPPER 70S TO MID 80S...WITH TUESDAY LOOKING AT
MID 80S TO NEAR 90 DEGREES.
A LITTLE MORE UNCERTAINTY IN THE FORECAST ARISES FOR WEDNESDAY AND
THURSDAY...WITH THE POTENTIAL FOR PRECIP RETURNING. THE UPPER LEVEL
RIDGE LOOKS TO BECOME BROKEN DOWN...FROM BOTH THE LOW WHICH HAD BEEN
SET UP OVER MEX SHIFTING EAST INTO THE PLAINS...AND ADDITIONAL
ENERGY SLIDING IN FROM THE PAC NW. PLENTY OF THINGS TO IRON OUT IN
THE COMING DAYS...BUT AT THIS POINT KEPT POPS CONFINED TO THE
WED/THURS DAYTIME PERIOD...HOWEVER HAVE NO DOUBT THE TIMING WILL BE
ADJUSTED. THESE DISTURBANCES LOOK TO BRING THE POTENTIAL FOR SFC
FRONTS MOVING INTO THE AREA...WITH A SLIGHT DECREASE IN TEMPS...WITH
HIGHS BOTH DAYS CURRENTLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 655 PM CDT THU MAY 9 2013
BIGGEST CONCERN WILL BE LOWERING CEILINGS AND REDUCED VISIBILITY.
MODELS ARE INDICATING A DECLINE IN CONDITIONS OVERNIGHT AND THEN A
RECOVERY TO VFR CONDITIONS FOR FRIDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
258 PM CDT WED MAY 8 2013
.DISCUSSION...
PRECIPITATION CHANCES TONIGHT INTO THURSDAY MAIN FORECAST FOCUS IN
THE SHORTER TERM. EXTENDED FORECAST WILL DEAL WITH A RELATIVELY
BRIEF BUT SUBSTANTIAL COOLDOWN THIS WEEKEND...FOLLOWED BY A MUCH
WARMER PATTERN NEXT WEEK.
AFTERNOON SATELLITE IMAGERY SHOWED A COMPACT UPPER CIRC CENTER
PIVOTING TOWARD NERN NEBR WITH ANOTHER UPPER WAVE MOVG INTO ERN
KS. REMNANT SHOWER ACTIVITY ON A LOBE MOVING AROUND SD UPPER LOW
WAS MOVG TOWARD FAR ERN ZONES AS OF 19Z...WITH SCATTERED
CONVECTION DEVELOPING NEAR THERMAL BOUNDARY BETWEEN PRECIP COOLED
AIR AND LOCATIONS WHICH HAD CLEARED UNDER UPPER THERMAL TROUGH IN
NERN NEBR. WOULD EXPECTED SCATTERED CONVECTION NERN ZONES INTO AT
LEAST EARLY THIS EVENING. ANOTHER AREA WHERE ACTIVITY COULD BE
MORE WIDESPREAD...ESPECIALLY EARLY THIS EVENING...WOULD APPEAR TO
BE NEAR WARM FRONT WHICH HAD LIFTED INTO FAR SRN NEBR. IN FACT
EVEN IF CURRENT ACTIVITY DVLPG NEAR SRN NEBR BOUNDARY DECREASES
EARLY THIS EVENING...WE COULD SEE ADDITIONAL DEVELOPMENT LATE THIS
EVENING AS SUGGESTED BY THE HRRR AND 4KM WRF AS LOW LEVEL JET
STRENGTHENS SOUTH OF BOUNDARY. THE LATTER MODEL EVEN SUGGESTED
NERN NEBR ACTIVITY WOULD BEGIN TURNING SE LATER THIS EVENING
MEETING UP WITH ANY CONVECTION THAT WOULD INCREASE IN SERN NEBR
LATE THIS EVENING. GENERALLY INCREASED POPS MOST AREAS EARLY
TONIGHT AND LATEST TRENDS WILL CONTINUE TO BE MONITORED FOR LAST
MINUTE CHANGES TO 00Z-03Z PD. AS UPPER LOW OVR SD BEGINS OPENING
UP/DROPPING SE LATE TONIGHT...SOME LIGHT SHOWERS COULD MOVE BACK
INTO NERN NEBR TOWARD THU MORNING WITH A CONTINUED SOUTHWARD PUSH
OF THESE GENERALLY LIGHT SHOWERS THURSDAY MORNING. IN
ADDITION...HEATING AND UPPER LOW REMNANTS ON THURSDAY COULD BRING
SCATTERED SHOWERS/TSTMS JUST ABOUT ANYWHERE THURSDAY AFTN AND SOME
POPS WERE ADDED ALL ZONES. GFS/NAM LINGERED QUITE A BIT OF LOW
LEVEL MOISTURE ACROSS MUCH OF THE FORECAST AREA ON THURSDAY WHICH
COULD LIMIT THIS HEATING AND COULD PROVIDE A PSBL NEGATIVE.
FOR NOW FORECAST WAS KEPT DRY THURSDAY NIGHT ALTHOUGH COULD SEE A
LINGERING LIGHT SHOWER/ISOLD TSTM EARLY. CLEARING THEN EXPECTED
FRIDAY WITH RELATIVELY LIGHT WINDS AND SEASONAL OR SLIGHTLY COOLER
TEMPERATURES. A STRONG COLD FRONT STILL ON TRACK TO RACE ACROSS
THE AREA FRIDAY NIGHT WITH GUSTY WINDS AND COOLER READINGS
ON SATURDAY. MAINTAINED SMALL POPS WITH FRONTS PASSAGE NRN ZONES
FRI NIGHT BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE ANY CHCS
FARTHER SOUTH. GUSTY NRLY WINDS LIKELY SATURDAY AS SUB-ZERO H85
AIR MOVES INTO NRN ZONES EARLY IN THE DAY BEFORE MODERATING.
AIRMASS IS COOL/DRY ENOUGH SO THAT WITH DECREASING WINDS SAT NIGHT
SEE NO REASON LOWS WON/T GET AT LEAST AS COOL AS LATEST MEX MOST
AREAS. THIS COULD LEAD TO SCATTERED FROST SUNDAY MORNING IF DWPTS
DON/T DRY OUT TOO MUCH. NO FROST WAS MENTIONED AT THIS TIME...BUT
IT IS CERTAINLY POSSIBLE.
WARMING TREND STILL ON TRACK THEN INTO NEXT WEEK WITH TUESDAY
LOOKING EXCEPTIONALLY WARM AHEAD OF COOL FRONT THAT SHOULD KNOCK A
FEW DEGREES OFF OF HIGHS BY DAY 7. A DRY FORECAST WAS MAINTAINED
IN THE EXTENDED UNTIL ALONG AND POST FRONTAL TUE NIGHT/WEDNESDAY.
CHERMOK
&&
.AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
A COUPLE OF WEATHER FEATURES IN THE PROXIMITY OF EASTERN NEBRASKA
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS IN THE FORECAST
THROUGH THIS EVENING AND A FEW SHOWERS OR SOME DRIZZLE INTO
THURSDAY. CIGS WILL GENERALLY BE VFR WITH SOME PATCHY MVFR CIGS
AND VSBYS WITH THE SCATTERED RAINSHOWERS IN THE AREA. AS HEATING
CONTINUES THIS AFTERNOON SHOULD SEE ADDITIONAL SHOWER DEVELOPMENT
ALONG WITH SOME ISOLATED THUNDERSTORMS. LATER TONIGHT THE BETTER
CHANCE FOR THUNDERSTORMS WILL BE ACROSS KANSAS AND SOUTH OF THE
TAF SITES. THUNDERSTORM POTENTIAL TOO LOW TO MENTION IN THE TAFS
THIS AFTERNOON AND TONIGHT. MVFR AND IFR CIGS AREA FORECAST TO
BECOME MORE WIDESPREAD AFTER 06Z. SOUTH WINDS SHIFT TO THE
NORTHEAST THEN NORTHWEST AND INCREASE TO ABOVE 15KTS AFTER 15Z.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
744 AM EDT WED MAY 8 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL BRING INCREASING CLOUDS ALONG WITH A
CHANCE OF SHOWERS AND COOLER TEMPERATURES TO THE REGION BY LATER
TODAY INTO THURSDAY. A COLD FRONT WILL SWING INTO THE AREA BY FRIDAY
INTO SATURDAY WITH A WIDESPREAD AND WELCOMED RAINFALL LIKELY. COOL
AND MAINLY DRY WEATHER WILL RETURN BY SUNDAY INTO MONDAY OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 630 AM EDT WEDNESDAY...MODEST UPDATES TO DEWPOINTS THROUGH
TODAY PER LATEST OBS AND RUC13 DATA. ALSO TWEAKED HOURLY
TEMPERATURES OVER THE NEXT FEW HOURS TO ACCOUNT FOR CURRENT
OBSERVATIONAL TRENDS. NO APPRECIABLE CHANGES TO WORDED FORECAST
HOWEVER. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS...
HIGH PRESSURE WHICH BROUGHT WARM AND DRY WEATHER TO THE REGION FOR
OVER A WEEK WILL FINALLY SLIDE EAST AND ALLOW UPPER LEVEL LOW
PRESSURE TO PUSH NORTHWARD FROM THE MID ATLANTIC STATES. THUS
CLEAR/SUNNY SKIES THIS MORNING WILL GRADUALLY GIVE WAY TO
THICKENING CLOUD COVER FROM THE SOUTH THROUGH THE MORNING AND
AFTERNOON HOURS AS DEEPER MOISTURE SLOWLY PINWHEELS NORTH. HOWEVER
DRY LOWER LEVELS WILL KEEP MOST PRECIPITATION CONFINED TO OUR
CENTRAL AND SOUTHERN COUNTIES BY LATER THIS AFTERNOON WHERE A FEW
HEAVIER/CONVECTIVE DOWNPOURS WILL BE POSSIBLE PER THIS MORNING`S
HRRR/RAP PROGS. HIGH TEMPERATURES REFLECTIVE OF CLOUD
COVERAGE...WITH ONE MORE WARM DAY IN THE UPPER 70S TO AROUND 80
FAR NORTH...THOUGH ONLY IN THE LOWER TO MID 70S CENTRAL/SOUTH AS
CLOUDS ARRIVE EARLIER IN THE DAY. WINDS LIGHT TO MODERATE
SOUTHERLY AND OCCASIONALLY GUSTY THIS AFTERNOON ESPECIALLY IN THE
CHAMPLAIN VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
AS OF 356 AM EDT WEDNESDAY...BY TONIGHT...INITIAL MOISTURE BAND AND
ASSOCIATED RAIN SHOWERS WILL CONTINUE TO PIVOT NORTHWARD INTO THE
REGION...THOUGH WEAKEN OVER TIME AS INSTABILITY WANES AND PBL
TEMPERATURES COOL. HAVE MAINTAINED LIKELY (60%) POPS FOR OUR
SOUTHERN AND EASTERN COUNTIES TO ACCOUNT FOR THESE TRENDS WITH
LOWER VALUES NORTH AND WEST. BY LATER TONIGHT COVERAGE OF ACTIVITY
SHOULD LESSEN WITH SOME PATCHY BR/FG FORMATION ACROSS THE
MOUNTAINS AND EASTERN VERMONT. QPF TOTALS RANGING FROM A TENTH OF
AN INCH OR SO NORTH AND WEST...TO LOCALLY A QUARTER TO A THIRD OF
AN INCH SOUTH AND EAST. WITH AMPLE CLOUD COVER AND NEGLIGIBLE
THERMAL ADVECTION...LOWS TO HOLD RELATIVELY MILD AND MAINLY IN THE
50S.
BY THURSDAY INTO THURSDAY NIGHT UPPER LOW DRIFTS INTO THE REGION
WHILE WEAKENING INTO AN OPEN WAVE OVER TIME AS IT CONTINUES TO
PROGRESS NORTHEAST. DESPITE A FEW PEEKS OF SUN HERE AND
THERE...IDEA WILL BE FOR PLENTY OF CLOUDS ALONG WITH A DECENT
COVERAGE OF SHOWER ACTIVITY AND A FEW STORMS...WITH BEST COVERAGE
DURING CONVECTIVE MAX PERIOD FROM EARLY AFTERNOON THROUGH EARLY
EVENING. A QUICK LOOK AT SOUNDING PROFILES SHOW VERY LIGHT WINDS
THROUGH THE PBL SO ACTIVITY WILL BE SLOW MOVING AND TEND TO DRIFT
AROUND. SO WHILE AVERAGE QPF SHOULD ONLY BE IN THE 0.10 TO 0.30 INCH
RANGE THERE COULD BE SCATTERED HEAVIER POINT TOTALS...ESPECIALLY IN
THOSE AREAS RECEIVING HEAVIER CONVECTIVE DOWNPOURS. WCD VALUES QUITE
LOW HOWEVER...SO ONLY AVERAGE PRECIP EFFICIENCY WILL EXIST IN CELL
CORES AND CERTAINLY NO HYDRO CONCERNS GIVEN OUR RECENT DRY STRETCH.
HIGHS COOLER BUT STILL SEASONABLY MILD...TOPPING OUT GENERALLY IN
THE 65 TO 72 RANGE. LOWS THURSDAY NIGHT UPPER 40S TO LOWER 50S.
BY FRIDAY MODELS REMAIN GOOD OVERALL CONSISTENCY IN SHOWING FIRST OF
TWO COLD FRONTAL BOUNDARIES TO SLIDE INTO OUR REGION. A FRONTAL WAVE
OF LOW PRESSURE WILL BE RIDING NORTHEAST DURING THE PERIOD AND THIS
FEATURE WILL SLOW THE BOUNDARY...BRINGING A SOAKING THOUGH WELCOMED
RAINFALL TO THE REGION BY THE AFTERNOON AND EVENING HOURS. SOME
SUBTLE NORTH/SOUTH DIFFERENCES IN PLACEMENT OF HEAVIER QPF AXIS BUT
OVERALL IDEA WILL BE FOR A WET AFTERNOON AND HIGHER/LIKELY POPS
ACROSS OUR AREA. TEMPERATURES RANGING THROUGH THE 60S ACROSS NRN NY
WHERE RAINFALL WILL ARRIVE EARLIER IN THE DAY...AND 65 TO 70 OR SO
ACROSS VT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 420 AM EDT WEDNESDAY...UNSETTLED WEATHER CONTINUES INTO THE
LONG TERM WITH SFC LOW OVER THE NE GAINING MOMENTUM EWD...AS UPR
LVL LOW/TROUGH PUSHES EAST INTO ERN ONTARIO FRIDAY NIGHT THROUGH
SATURDAY. A BRIEF BREAK IN PRECIP MAY OCCUR LATE SATURDAY INTO
SATURDAY NIGHT AS DRY SLOT TRIES TO REACH NWD INTO NRN NY AND VT
AS THE FIRST SFC LOW WEAKENS AND SHIFTS EAST AND LOW ASSOCIATED
WITH UPR TROUGH MOVES ACROSS JAMES BAY...DRAGGING A COLD FRONT
WITH IT. THREAT OF PRECIP BEGINS TO TAPER OFF LATE SUNDAY WITH
SFC RIDGING BEGINNING TO BUILD INTO WRN NY. COLDER AIR WILL
FILTER IN WITH CONTINUED NW FLOW. NEXT THREAT FOR PRECIP WILL
ARRIVE TUESDAY NIGHT.
ABOVE NORMAL TEMPERATURES FOR THE BEGINNING OF THE PERIOD WILL
TREND COOLER BEHIND THE COLD FRONT MOVING THROUGH FRIDAY
NIGHT...WITH REINFORCED COLD AIR MOVING INTO THE NORTH COUNTRY
SATURDAY NIGHT INTO SUNDAY. MIN TEMPS IN THE 40S FRIDAY AND
SATURDAY NIGHT WILL COOL INTO THE 30S SUNDAY NIGHT THROUGH MONDAY
NIGHT. DURING THE DAY...MAX TEMPS IN THE 60S ON SATURDAY AND
SUNDAY WILL COOL INTO THE 50S MONDAY TO L60S ON TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...MID AND HIGH LEVEL CLOUDS SPREADING
NORTHWARD OVER SRN VT AND ADKS. VFR CONDITIONS WILL PERSIST
THROUGH AT LEAST EARLY AFTN BEFORE A CLOSED UPR LOW LIFTING NORTH
BRINGS SOME ISOLD/SCATTERED RAIN SHOWERS AND AN ISOLATED TSTM
THIS AFTN INTO OVERNIGHT. EXPECT VFR SHOWERS TO START AT
BTV...PBG...MPV...RUT...SLK AFT 20Z. MSS EXPECTING VCSH IN THE
EVENING HOURS. ALL TAF SITES EXPECTING PERIOD OF MVFR CONDITIONS
OVERNIGHT...MAINLY IN THE FORM OF LOW CIGS...BUT MPV...SLK AND
MSS WILL HAVE LGTR WINDS AND LIKELY TO SEE SOME MVFR VSBYS FROM
FG DEVELOPMENT.
OUTLOOK 12Z THURSDAY THROUGH SUNDAY...
12Z THURSDAY ONWARD...CHANCE OF RAIN SHOWERS CONTINUE ACROSS THE
REGION THROUGH FRIDAY NIGHT...WITH SOME MVFR CONDITIONS POSSIBLE
IN RAIN SHOWERS. A COLD FRONT WILL MOVE INTO THE REGION ON FRIDAY
AND THEN BECOME NEARLY STATIONARY...WITH A CHANCE OF RAIN SHOWERS
FRIDAY AND SATURDAY...WITH SOME AREAS OF MVFR POSSIBLE. SUNDAY
THE FRONT WILL GAIN MOMENTUM EASTWARD AS UPPER LEVEL LOW MOVES
SOUTH OF JAMES BAY.
&&
.FIRE WEATHER...
A CHANGE IN THE WEATHER PATTERN WILL INCREASE THE CHANCES FOR SCATTERED
RAIN SHOWERS TODAY THROUGH THIS UPCOMING WEEKEND. IN ADDITION...
COOLER TEMPERATURES AND HIGHER RELATIVE HUMIDITY LEVELS CAN BE
EXPECTED WITH A WIDESPREAD WETTING RAIN POSSIBLE FRIDAY INTO
SATURDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
630 AM EDT WED MAY 8 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL BRING INCREASING CLOUDS ALONG WITH A
CHANCE OF SHOWERS AND COOLER TEMPERATURES TO THE REGION BY LATER
TODAY INTO THURSDAY. A COLD FRONT WILL SWING INTO THE AREA BY FRIDAY
INTO SATURDAY WITH A WIDESPREAD AND WELCOMED RAINFALL LIKELY. COOL
AND MAINLY DRY WEATHER WILL RETURN BY SUNDAY INTO MONDAY OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 630 AM EDT WEDNESDAY...MODEST UPDATES TO DEWPOINTS THROUGH
TODAY PER LATEST OBS AND RUC13 DATA. ALSO TWEAKED HOURLY
TEMPERATURES OVER THE NEXT FEW HOURS TO ACCOUNT FOR CURRENT
OBSERVATIONAL TRENDS. NO APPRECIABLE CHANGES TO WORDED FORECAST
HOWEVER. HAVE A GREAT DAY. PRIOR DISCUSSION FOLLOWS...
HIGH PRESSURE WHICH BROUGHT WARM AND DRY WEATHER TO THE REGION FOR
OVER A WEEK WILL FINALLY SLIDE EAST AND ALLOW UPPER LEVEL LOW
PRESSURE TO PUSH NORTHWARD FROM THE MID ATLANTIC STATES. THUS
CLEAR/SUNNY SKIES THIS MORNING WILL GRADUALLY GIVE WAY TO
THICKENING CLOUD COVER FROM THE SOUTH THROUGH THE MORNING AND
AFTERNOON HOURS AS DEEPER MOISTURE SLOWLY PINWHEELS NORTH. HOWEVER
DRY LOWER LEVELS WILL KEEP MOST PRECIPITATION CONFINED TO OUR
CENTRAL AND SOUTHERN COUNTIES BY LATER THIS AFTERNOON WHERE A FEW
HEAVIER/CONVECTIVE DOWNPOURS WILL BE POSSIBLE PER THIS MORNING`S
HRRR/RAP PROGS. HIGH TEMPERATURES REFLECTIVE OF CLOUD
COVERAGE...WITH ONE MORE WARM DAY IN THE UPPER 70S TO AROUND 80
FAR NORTH...THOUGH ONLY IN THE LOWER TO MID 70S CENTRAL/SOUTH AS
CLOUDS ARRIVE EARLIER IN THE DAY. WINDS LIGHT TO MODERATE
SOUTHERLY AND OCCASIONALLY GUSTY THIS AFTERNOON ESPECIALLY IN THE
CHAMPLAIN VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
AS OF 356 AM EDT WEDNESDAY...BY TONIGHT...INITIAL MOISTURE BAND AND
ASSOCIATED RAIN SHOWERS WILL CONTINUE TO PIVOT NORTHWARD INTO THE
REGION...THOUGH WEAKEN OVER TIME AS INSTABILITY WANES AND PBL
TEMPERATURES COOL. HAVE MAINTAINED LIKELY (60%) POPS FOR OUR
SOUTHERN AND EASTERN COUNTIES TO ACCOUNT FOR THESE TRENDS WITH
LOWER VALUES NORTH AND WEST. BY LATER TONIGHT COVERAGE OF ACTIVITY
SHOULD LESSEN WITH SOME PATCHY BR/FG FORMATION ACROSS THE
MOUNTAINS AND EASTERN VERMONT. QPF TOTALS RANGING FROM A TENTH OF
AN INCH OR SO NORTH AND WEST...TO LOCALLY A QUARTER TO A THIRD OF
AN INCH SOUTH AND EAST. WITH AMPLE CLOUD COVER AND NEGLIGIBLE
THERMAL ADVECTION...LOWS TO HOLD RELATIVELY MILD AND MAINLY IN THE
50S.
BY THURSDAY INTO THURSDAY NIGHT UPPER LOW DRIFTS INTO THE REGION
WHILE WEAKENING INTO AN OPEN WAVE OVER TIME AS IT CONTINUES TO
PROGRESS NORTHEAST. DESPITE A FEW PEEKS OF SUN HERE AND
THERE...IDEA WILL BE FOR PLENTY OF CLOUDS ALONG WITH A DECENT
COVERAGE OF SHOWER ACTIVITY AND A FEW STORMS...WITH BEST COVERAGE
DURING CONVECTIVE MAX PERIOD FROM EARLY AFTERNOON THROUGH EARLY
EVENING. A QUICK LOOK AT SOUNDING PROFILES SHOW VERY LIGHT WINDS
THROUGH THE PBL SO ACTIVITY WILL BE SLOW MOVING AND TEND TO DRIFT
AROUND. SO WHILE AVERAGE QPF SHOULD ONLY BE IN THE 0.10 TO 0.30 INCH
RANGE THERE COULD BE SCATTERED HEAVIER POINT TOTALS...ESPECIALLY IN
THOSE AREAS RECEIVING HEAVIER CONVECTIVE DOWNPOURS. WCD VALUES QUITE
LOW HOWEVER...SO ONLY AVERAGE PRECIP EFFICIENCY WILL EXIST IN CELL
CORES AND CERTAINLY NO HYDRO CONCERNS GIVEN OUR RECENT DRY STRETCH.
HIGHS COOLER BUT STILL SEASONABLY MILD...TOPPING OUT GENERALLY IN
THE 65 TO 72 RANGE. LOWS THURSDAY NIGHT UPPER 40S TO LOWER 50S.
BY FRIDAY MODELS REMAIN GOOD OVERALL CONSISTENCY IN SHOWING FIRST OF
TWO COLD FRONTAL BOUNDARIES TO SLIDE INTO OUR REGION. A FRONTAL WAVE
OF LOW PRESSURE WILL BE RIDING NORTHEAST DURING THE PERIOD AND THIS
FEATURE WILL SLOW THE BOUNDARY...BRINGING A SOAKING THOUGH WELCOMED
RAINFALL TO THE REGION BY THE AFTERNOON AND EVENING HOURS. SOME
SUBTLE NORTH/SOUTH DIFFERENCES IN PLACEMENT OF HEAVIER QPF AXIS BUT
OVERALL IDEA WILL BE FOR A WET AFTERNOON AND HIGHER/LIKELY POPS
ACROSS OUR AREA. TEMPERATURES RANGING THROUGH THE 60S ACROSS NRN NY
WHERE RAINFALL WILL ARRIVE EARLIER IN THE DAY...AND 65 TO 70 OR SO
ACROSS VT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 420 AM EDT WEDNESDAY...UNSETTLED WEATHER CONTINUES INTO THE
LONG TERM WITH SFC LOW OVER THE NE GAINING MOMENTUM EWD...AS UPR
LVL LOW/TROUGH PUSHES EAST INTO ERN ONTARIO FRIDAY NIGHT THROUGH
SATURDAY. A BRIEF BREAK IN PRECIP MAY OCCUR LATE SATURDAY INTO
SATURDAY NIGHT AS DRY SLOT TRIES TO REACH NWD INTO NRN NY AND VT
AS THE FIRST SFC LOW WEAKENS AND SHIFTS EAST AND LOW ASSOCIATED
WITH UPR TROUGH MOVES ACROSS JAMES BAY...DRAGGING A COLD FRONT
WITH IT. THREAT OF PRECIP BEGINS TO TAPER OFF LATE SUNDAY WITH
SFC RIDGING BEGINNING TO BUILD INTO WRN NY. COLDER AIR WILL
FILTER IN WITH CONTINUED NW FLOW. NEXT THREAT FOR PRECIP WILL
ARRIVE TUESDAY NIGHT.
ABOVE NORMAL TEMPERATURES FOR THE BEGINNING OF THE PERIOD WILL
TREND COOLER BEHIND THE COLD FRONT MOVING THROUGH FRIDAY
NIGHT...WITH REINFORCED COLD AIR MOVING INTO THE NORTH COUNTRY
SATURDAY NIGHT INTO SUNDAY. MIN TEMPS IN THE 40S FRIDAY AND
SATURDAY NIGHT WILL COOL INTO THE 30S SUNDAY NIGHT THROUGH MONDAY
NIGHT. DURING THE DAY...MAX TEMPS IN THE 60S ON SATURDAY AND
SUNDAY WILL COOL INTO THE 50S MONDAY TO L60S ON TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...VFR CONDITIONS WILL PERSIST THROUGH THE
REST OF THE NIGHT AND FOR THE FIRST HALF OF WEDNESDAY BEFORE A
CLOSED UPR LOW ACROSS THE MID-ATLANTIC STATES GRADUALLY LIFTS
NWD...BRINGING SOME ISOLD/SCATTERED RAIN SHOWERS AND AN ISOLATED
TSTM THIS AFTN INTO EVENING. CLDS INCREASING FROM THE SOUTH LATE
THIS MORNING FOLLOWED BY VFR SHOWERS AT BTV...MPV...RUT...SLK AFT
20/21Z. WITH VFR SHOWERS AT PBG AFTER 00Z AS LOW-LEVELS QUITE DRY
TO START SO COVERAGE OF ACTIVITY SHOULD BE SLOW TO DEVELOP NWD
DURING WED AFTN AND EVENING. MSS EXPECTING VCSH IN THE EVENING
HOURS. SOME MVFR CIGS EXPECTED AT KMPV IN THE LATE EVENING.
EXPECT WINDS DURING THE DAYLIGHT HRS WEDNESDAY WILL GENERALLY BE
SSE 10-15 KTS WITH INCREASING GRADIENT FLOW AND SOME GUSTS OF
15-20 KTS. WINDS EXPECTED TO SUBSIDE OVERNIGHT WEDNESDAY NIGHT TO
LESS THAN 10KTS.
OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
06Z THURSDAY ONWARD...CHANCE OF RAIN SHOWERS CONTINUE ACROSS THE
REGION WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...WITH SOME MVFR
CONDITIONS POSSIBLE IN RAIN SHOWERS. A COLD FRONT WILL MOVE INTO
THE REGION ON FRIDAY AND THEN BECOME NEARLY STATIONARY...WITH A
CHANCE OF RAIN SHOWERS FRIDAY AND SATURDAY...WITH SOME AREAS OF
MVFR POSSIBLE. SUNDAY THE FRONT WILL GAIN MOMENTUM EASTWARD AS
UPPER LEVEL LOW MOVES SOUTH OF JAMES BAY.
&&
.FIRE WEATHER...
A CHANGE IN THE WEATHER PATTERN WILL INCREASE THE CHANCES FOR SCATTERED
RAIN SHOWERS TODAY THROUGH THIS UPCOMING WEEKEND. IN ADDITION...
COOLER TEMPERATURES AND HIGHER RELATIVE HUMIDITY LEVELS CAN BE
EXPECTED WITH A WIDESPREAD WETTING RAIN POSSIBLE FRIDAY INTO
SATURDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...KGM
AVIATION...KGM
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
651 PM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LOW WILL LIFT NORTH AND AWAY FROM THE AREA OVERNIGHT.
HIGH PRESSURE WILL BRING WARMER AND DRIER CONDITIONS THURSDAY
AND FRIDAY. SHOWERS AND THUNDERSTORMS WILL RETURN OVER THE WEEKEND
AS A COLD FRONT CROSSES THE REGION. STRONG HIGH PRESSURE BUILDING
INTO THE AREA EARLY NEXT WEEK WILL BRING MUCH COOLER WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 6:45 PM WEDNESDAY...A BROKEN LINE OF LIGHT TO MODERATE
SHOWERS IS ENTERING THE FORECAST AREA FROM THE NW. THIS IS AS
ANTICIPATED...SEE PREVIOUS DISCUSSION BELOW. THUS FAR THE
CONVECTION HAS STAYED WEST OF I-95. WILL UPDATE FORECAST IF THE
SHOWERS SHOW ANY SIGN OF MAKING IT MUCH FURTHER EAST. HAVE
ADJUSTED THE TEMPERATURE CURVE IN THE GRIDDED DATABASE TO REFLECT
SLOWER THAN EXPECTED COOLING. FORECAST OTHERWISE REMAINS ON TRACK
WITH LATEST UPDATE.
LARGE UPPER LOW CONTINUES TO INFLUENCE THE SENSIBLE WEATHER ACROSS
THE AREA AS EVIDENCED BY COUNTERCLOCKWISE ROTATING CLOUD SHIELD ON
VISIBLE IMAGERY. IMPACTS TODAY ARE DISPLACED MUCH FURTHER NORTH
THAN YESTERDAY THANKS TO THE LOW PROGRESSING SLOWLY NE...BUT THE
SLIGHTLY STEEPENED ML LAPSE RATES BENEATH THE 500MB COLD POOL ARE
CREATING WIDESPREAD DIURNAL CU TODAY. WHILE SURFACE TEMPS HAVE
WARMED WELL INTO THE 70S...SOME MID LEVEL DRY AIR AND WEAK
SUBSIDENCE BEHIND THE LOW HAS LIMITED CONVECTION THUS FAR ACROSS
THE CWA. HOWEVER...MORE AGITATED CU TO THE NORTH HAS SPAWNED A FEW
SHOWERS AND STORMS. HIGH RES GUIDANCE AND SREF PROBS CONTINUE TO
INDICATE THAT A FEW SHOWERS WITH AN ISOLATED STORM MAY DEVELOP AND
PUSH E/SE INTO THE NORTHERN EDGES OF THE CWA LATE THIS EVE. BASED
OFF ONGOING CU DEVELOPMENT...FEEL THIS IS POSSIBLE AND HAVE LEFT
SCHC POP THROUGH JUST AFTER NIGHTFALL...FOR I-95 AND NW FROM
THERE. THE REST OF THE CWA WILL REMAIN DRY TODAY.
ANY CONVECTION WILL DECAY RAPIDLY AFTER DARK LEAVING JUST SCATTERED
DEBRIS CLOUDINESS TONIGHT. WEAK PRESSURE GRADIENT WILL HELP WINDS
BECOME LIGHT TONIGHT...BUT SOME SLIGHTLY STRONGER LOW LEVEL WINDS
WILL KEEP THE SURFACE FROM FULLY DECOUPLING...ESPECIALLY ACROSS THE
EASTERN 2/3 OF THE CWA. ADDITIONALLY...SOME RESIDUAL MID LEVEL
MOISTURE EVIDENT IN FORECAST SOUNDINGS WILL ALSO HELP LIMIT
OVERALL LONGWAVE COOLING. FOR THESE REASONS HAVE GONE SLIGHTLY ABOVE
MOS NUMBERS FOR LOWS...MID 50S INLAND TO NEAR 60 AT THE COAST...AND
HAVE NOT INCLUDED ANY MENTION OF FOG IN THE WX GRIDS...ALTHOUGH SOME
SHALLOW FOG IS POSSIBLE ACROSS INLAND ZONES TOWARDS MORNING.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...A WARMING TREND THE MAIN HEADLINE BOTH
THURSDAY AND FRIDAY AS AN UPPER LOW LIFTS AWAY FROM THE AREA
AND UPPER HEIGHTS SNAP BACK TO MORE CLIMATOLOGICAL STANDARDS
FOR EARLY MAY. COLUMN DRYING INDUCED BY SUBSIDENCE ALOFT WILL
PREVAIL THROUGH THURSDAY AND INTO EARLY FRIDAY...SQUELCHING
RAIN CHANCES. MOISTURE ADVECTION IN SW FLOW LATE FRIDAY WILL
BRING A SLIGHT CHANCE OF PRE-FRONTAL SHOWERS FRIDAY NIGHT.
DAYTIME HIGHS IN THE 80S BOTH DAYS...EXCEPT UPPER 70S ALONG
THE IMMEDIATE COAST. THE DAYTIME LAND VS WATER TEMPERATURE
DIFFERENTIAL BOTH DAYS WILL SERVE AS THE ENGINE THAT DRIVES A
ROBUST SEA BREEZE CIRCULATION...WHICH COULD BRING MAXIMUM
TEMPERATURES NEAR THE COAST EARLIER IN THE DAY...COMPARED TO
THE TYPICAL DIURNAL MAXIMUM HEATING TIME.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...MEDIUM RANGE GUIDANCE REMAINS STABLE WITH
A SIGNIFICANT FRONT SLATED TO MOVE ACROSS THE AREA LATE SUNDAY
FOLLOWED BY YET ANOTHER COLD AIR MASS. WPC MID LEVEL GRAPHICS ARE
A MIX OF MAINLY THE ECMWF PRODUCTS EARLY IN THE PERIOD FOLLOWED BY
A SMATTERING OF GEM AND GFS LATER IN THE PERIOD.
FOR SATURDAY...SYNOPTIC FORCING WILL CONSIST OF LOW LEVEL SPEED
CONVERGENCE PRODUCING MOSTLY SHOWERS AND STREAMERS OFF THE ATLANTIC.
THIS IS A TYPICAL SCENARIO FOR OUR AREA. THE ECMWF IS THE SLOWER OF
THE GUIDANCE AND OFFERS THE BEST COUPLING OF INSTABILITY AND FORCING
FOR THE COAST SUNDAY AND WE ARE NOW ADVERTISING LIKELY POPS.
ENSEMBLES SHOW 500MB HEIGHTS APPROACHING TWO STANDARD DEVIATIONS
BELOW NORMAL EARLY NEXT WEEK. 850MB TEMPERATURES DIP TO AROUND THREE
DEGREES CELSIUS LATE MONDAY AND TUESDAY. A COUPLED BOUNDARY LAYER
WILL LIKELY KEEP OVERNIGHT LOWS A LITTLE ABOVE GUIDANCE. WIDESPREAD
LOWS IN THE 40S CAN BE EXPECTED TUESDAY WITH A SMATTERING OF 40S
WEDNESDAY MORNING. DOWNSLOPING AND A STRONG MID MAY SUN ANGLE WILL
ALLOW DAYTIME TEMPERATURES TO RISE INTO THE 70S.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS CU BEGINNING TO DEVELOP
OVER THE CWA WITH DAYTIME HEATING. EXPECT THIS TREND TO CONTINUE
THRU THE AFTN WITH SCT CLOUDS 4-5KFT AND SOUTHWEST WINDS 10-15 KTS.
HAVE REMOVED VCSH FOR KLBT AS LATEST HRRR RUNS KEEP ALL SHOWER
ACTIVITY WELL NORTH OF OUR AREA...AND LATEST SATELLITE SHOWS THAT
STILL ONLY SHALLOW CU PRESENT IN THE VICINITY. CLOUD COVER
DIMINISHES TONIGHT... BUT ENHANCED LOW-LEVEL WINDS LIKELY WILL LIMIT
FOG DEVELOPMENT. IT APPEARS PATCHY FOG IS MOST LIKELY AT
KFLO/KLBT...AS THE NEAR SFC WINDS WEAKEN AFTER 06Z AND THE MODEL
SOUNDINGS DEPICT BETTER RADIATIONAL COOLING. CONFIDENCE IS STILL
FAIRLY LOW...BUT ADDED TEMPO MVFR VSBYS FOR THE INLAND TERMS IN THE
09-12Z TIME FRAME. EXPECT VFR CONDITIONS AGAIN ON THURSDAY WITH W-SW
WINDS AOB 10 KTS.
EXTENDED OUTLOOK...MVFR/TEMPO IFR IN MORNING FOG FRIDAY. CHANCE OF
SHOWERS SATURDAY AND SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:45 PM WEDNESDAY...LATEST OBS SHOW 2 TO 4 FT SEAS WITH SW
WINDS IN THE 15 KT RANGE. NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS:
BROAD LOW PRESSURE TO THE NW OF THE WATERS WILL KEEP SW WINDS
ONGOING THROUGH THE PERIOD..WITH THE SLIGHT ENHANCEMENT IN THE
NEAR-SHORE WATERS DUE TO THE SEA BREEZE WEAKENING AFTER SUNSET.
WINDS WILL REMAIN 10-15 KTS ACROSS THE WATERS THROUGH
TONIGHT...WITH SCATTERED GUSTS ABOVE 20 KTS POSSIBLE. SEAS WILL
BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE DECREASING
EASTERLY SWELL...WHICH WILL CREATE SHORTENING PERIODS. EXPECT
PREDOMINANTLY 2-4 FT SEAS THROUGH TONIGHT...WITH A 10 SEC EASTERLY
SWELL AND 5 SEC SW WIND WAVE COMPRISING THE SPECTRUM.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...MODERATE SW WINDS TO PREVAIL THU AND FRI
AS HIGH PRESSURE REMAINS POSITIONED OVER THE OFFSHORE WATERS WITH
WEAK LOW PRESSURE INLAND. GENERALLY 15 KNOTS OR LESS...EXCEPT GUSTS
TO 20 KT IN THE MIDDLE AFTERNOON TO EARLY EVENING NEAR SHORE IN
THE PEAK OF THE SEA BREEZE CIRCULATION INDUCED BY LAND HEATING.
SEAS GENERALLY 2-4 FT AND HIGHEST OFFSHORE...COMPOSED OF MODERATE
SW CHOP MIXED WITH 1-2 SE WAVES EVERY 7-8 SECONDS. NO TSTMS OR
RESTRICTIONS TO VISIBILITY EXPECTED ON THE WATERS THU AND FRI BUT
A FEW SHOWERS MAY DOT THE WATERS FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 PM WEDNESDAY...SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY
AND MOST OF THE DAY SUNDAY AHEAD OF A RELATIVELY SLOW MOVING COLD
FRONT. SPEEDS WILL BE MAINLY IN A RANGE OF 10-15 KNOTS MOSTLY
TOWARD THE HIGHER END. THE FRONT MOVES ACROSS THE WATERS SUNDAY
NIGHT WITH A NORTHERLY FLOW IN ITS WAKE. WIND SPEEDS INCREASE TO
15-20 KNOTS. SIGNIFICANT SEAS SHOW MOSTLY 2-4 FEET SATURDAY AND
SUNDAY INCREASING TO 3-5 FEET WITH THE INCREASE IN WINDS EARLY
MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK/JDW
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...MRR
MARINE...MJC/REK/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
314 PM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LOW WILL LIFT NORTH AND AWAY FROM THE AREA OVERNIGHT.
HIGH PRESSURE WILL BRING WARMER AND DRIER CONDITIONS THURSDAY
AND FRIDAY. SHOWERS AND THUNDERSTORMS WILL RETURN OVER THE WEEKEND
AS A COLD FRONT CROSSES THE REGION. STRONG HIGH PRESSURE BUILDING
INTO THE AREA EARLY NEXT WEEK WILL BRING MUCH COOLER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...LARGE UPPER LOW CONTINUES TO INFLUENCE THE
SENSIBLE WEATHER ACROSS THE AREA AS EVIDENCED BY COUNTERCLOCKWISE
ROTATING CLOUD SHIELD ON VISIBLE IMAGERY. IMPACTS TODAY ARE
DISPLACED MUCH FURTHER NORTH THAN YESTERDAY THANKS TO THE LOW
PROGRESSING SLOWLY NE...BUT THE SLIGHTLY STEEPENED ML LAPSE RATES
BENEATH THE 500MB COLD POOL ARE CREATING WIDESPREAD DIURNAL CU
TODAY. WHILE SURFACE TEMPS HAVE WARMED WELL INTO THE 70S...SOME MID
LEVEL DRY AIR AND WEAK SUBSIDENCE BEHIND THE LOW HAS LIMITED
CONVECTION THUS FAR ACROSS THE CWA. HOWEVER...MORE AGITATED CU TO
THE NORTH HAS SPAWNED A FEW SHOWERS AND STORMS. HIGH RES GUIDANCE
AND SREF PROBS CONTINUE TO INDICATE THAT A FEW SHOWERS WITH AN
ISOLATED STORM MAY DEVELOP AND PUSH E/SE INTO THE NORTHERN EDGES OF
THE CWA LATE THIS EVE. BASED OFF ONGOING CU DEVELOPMENT...FEEL THIS
IS POSSIBLE AND HAVE LEFT SCHC POP THROUGH JUST AFTER
NIGHTFALL...FOR I-95 AND NW FROM THERE. THE REST OF THE CWA WILL
REMAIN DRY TODAY.
ANY CONVECTION WILL DECAY RAPIDLY AFTER DARK LEAVING JUST SCATTERED
DEBRIS CLOUDINESS TONIGHT. WEAK PRESSURE GRADIENT WILL HELP WINDS
BECOME LIGHT TONIGHT...BUT SOME SLIGHTLY STRONGER LOW LEVEL WINDS
WILL KEEP THE SURFACE FROM FULLY DECOUPLING...ESPECIALLY ACROSS THE
EASTERN 2/3 OF THE CWA. ADDITIONALLY...SOME RESIDUAL MID LEVEL
MOISTURE EVIDENT IN FORECAST SOUNDINGS WILL ALSO HELP LIMIT
OVERALL LONGWAVE COOLING. FOR THESE REASONS HAVE GONE SLIGHTLY ABOVE
MOS NUMBERS FOR LOWS...MID 50S INLAND TO NEAR 60 AT THE COAST...AND
HAVE NOT INCLUDED ANY MENTION OF FOG IN THE WX GRIDS...ALTHOUGH SOME
SHALLOW FOG IS POSSIBLE ACROSS INLAND ZONES TOWARDS MORNING.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...A WARMING TREND THE MAIN HEADLINE BOTH
THURSDAY AND FRIDAY AS AN UPPER LOW LIFTS AWAY FROM THE AREA
AND UPPER HEIGHTS SNAP BACK TO MORE CLIMATOLOGICAL STANDARDS
FOR EARLY MAY. COLUMN DRYING INDUCED BY SUBSIDENCE ALOFT WILL
PREVAIL THROUGH THURSDAY AND INTO EARLY FRIDAY...SQUELCHING
RAIN CHANCES. MOISTURE ADVECTION IN SW FLOW LATE FRIDAY WILL
BRING A SLIGHT CHANCE OF PRE-FRONTAL SHOWERS FRIDAY NIGHT.
DAYTIME HIGHS IN THE 80S BOTH DAYS...EXCEPT UPPER 70S ALONG
THE IMMEDIATE COAST. THE DAYTIME LAND VS WATER TEMPERATURE
DIFFERENTIAL BOTH DAYS WILL SERVE AS THE ENGINE THAT DRIVES A
ROBUST SEA BREEZE CIRCULATION...WHICH COULD BRING MAXIMUM
TEMPERATURES NEAR THE COAST EARLIER IN THE DAY...COMPARED TO
THE TYPICAL DIURNAL MAXIMUM HEATING TIME.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...MEDIUM RANGE GUIDANCE REMAINS STABLE WITH
A SIGNIFICANT FRONT SLATED TO MOVE ACROSS THE AREA LATE SUNDAY
FOLLOWED BY YET ANOTHER COLD AIR MASS. WPC MID LEVEL GRAPHICS ARE
A MIX OF MAINLY THE ECMWF PRODUCTS EARLY IN THE PERIOD FOLLOWED BY
A SMATTERING OF GEM AND GFS LATER IN THE PERIOD.
FOR SATURDAY...SYNOPTIC FORCING WILL CONSIST OF LOW LEVEL SPEED
CONVERGENCE PRODUCING MOSTLY SHOWERS AND STREAMERS OFF THE ATLANTIC.
THIS IS A TYPICAL SCENARIO FOR OUR AREA. THE ECMWF IS THE SLOWER OF
THE GUIDANCE AND OFFERS THE BEST COUPLING OF INSTABILITY AND FORCING
FOR THE COAST SUNDAY AND WE ARE NOW ADVERTISING LIKELY POPS.
ENSEMBLES SHOW 500MB HEIGHTS APPROACHING TWO STANDARD DEVIATIONS
BELOW NORMAL EARLY NEXT WEEK. 850MB TEMPERATURES DIP TO AROUND THREE
DEGREES CELSIUS LATE MONDAY AND TUESDAY. A COUPLED BOUNDARY LAYER
WILL LIKELY KEEP OVERNIGHT LOWS A LITTLE ABOVE GUIDANCE. WIDESPREAD
LOWS IN THE 40S CAN BE EXPECTED TUESDAY WITH A SMATTERING OF 40S
WEDNESDAY MORNING. DOWNSLOPING AND A STRONG MID MAY SUN ANGLE WILL
ALLOW DAYTIME TEMPERATURES TO RISE INTO THE 70S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS CU BEGINNING TO DEVELOP
OVER THE CWA WITH DAYTIME HEATING. EXPECT THIS TREND TO CONTINUE
THRU THE AFTN WITH SCT CLOUDS 4-5KFT AND SOUTHWEST WINDS 10-15 KTS.
HAVE REMOVED VCSH FOR KLBT AS LATEST HRRR RUNS KEEP ALL SHOWER
ACTIVITY WELL NORTH OF OUR AREA...AND LATEST SATELLITE SHOWS THAT
STILL ONLY SHALLOW CU PRESENT IN THE VICINITY. CLOUD COVER
DIMINISHES TONIGHT... BUT ENHANCED LOW-LEVEL WINDS LIKELY WILL LIMIT
FOG DEVELOPMENT. IT APPEARS PATCHY FOG IS MOST LIKELY AT
KFLO/KLBT...AS THE NEAR SFC WINDS WEAKEN AFTER 06Z AND THE MODEL
SOUNDINGS DEPICT BETTER RADIATIONAL COOLING. CONFIDENCE IS STILL
FAIRLY LOW...BUT ADDED TEMPO MVFR VSBYS FOR THE INLAND TERMS IN THE
09-12Z TIME FRAME. EXPECT VFR CONDITIONS AGAIN ON THURSDAY WITH W-SW
WINDS AOB 10 KTS.
EXTENDED OUTLOOK...MVFR/TEMPO IFR IN MORNING FOG FRIDAY. CHANCE OF
SHOWERS SATURDAY AND SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...BROAD LOW PRESSURE TO THE NW OF THE WATERS
WILL KEEP SW WINDS ONGOING THROUGH THE PERIOD..WITH THE SLIGHT
ENHANCEMENT IN THE NEAR-SHORE WATERS DUE TO THE SEA BREEZE WEAKENING
AFTER SUNSET. WINDS WILL REMAIN 10-15 KTS ACROSS THE WATERS THROUGH
TONIGHT...WITH SCATTERED GUSTS ABOVE 20 KTS POSSIBLE. SEAS WILL
BECOME INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE DECREASING
EASTERLY SWELL...WHICH WILL CREATE SHORTENING PERIODS. EXPECT
PREDOMINANTLY 2-4 FT SEAS THROUGH TONIGHT...WITH A 10 SEC EASTERLY
SWELL AND 5 SEC SW WIND WAVE COMPRISING THE SPECTRUM.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...MODERATE SW WINDS TO PREVAIL THU AND FRI
AS HIGH PRESSURE REMAINS POSITIONED OVER THE OFFSHORE WATERS WITH
WEAK LOW PRESSURE INLAND. GENERALLY 15 KNOTS OR LESS...EXCEPT GUSTS
TO 20 KT IN THE MIDDLE AFTERNOON TO EARLY EVENING NEAR SHORE IN
THE PEAK OF THE SEA BREEZE CIRCULATION INDUCED BY LAND HEATING.
SEAS GENERALLY 2-4 FT AND HIGHEST OFFSHORE...COMPOSED OF MODERATE
SW CHOP MIXED WITH 1-2 SE WAVES EVERY 7-8 SECONDS. NO TSTMS OR
RESTRICTIONS TO VISIBILITY EXPECTED ON THE WATERS THU AND FRI BUT
A FEW SHOWERS MAY DOT THE WATERS FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 PM WEDNESDAY...SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY
AND MOST OF THE DAY SUNDAY AHEAD OF A RELATIVELY SLOW MOVING COLD
FRONT. SPEEDS WILL BE MAINLY IN A RANGE OF 10-15 KNOTS MOSTLY
TOWARD THE HIGHER END. THE FRONT MOVES ACROSS THE WATERS SUNDAY
NIGHT WITH A NORTHERLY FLOW IN ITS WAKE. WIND SPEEDS INCREASE TO
15-20 KNOTS. SIGNIFICANT SEAS SHOW MOSTLY 2-4 FEET SATURDAY AND
SUNDAY INCREASING TO 3-5 FEET WITH THE INCREASE IN WINDS EARLY
MONDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...BJR/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
127 PM EDT WED MAY 8 2013
.SYNOPSIS...
LOW PRESSURE...TO OUR NORTH...WILL CONTINUE TO MOVE SLOWLY AWAY FROM
THE AREA THROUGH TONIGHT. HIGH PRESSURE WILL FILL IN BEHIND THE
DEPARTING LOW...BRINGING WARMER AND DRIER CONDITIONS. SHOWERS AND
THUNDERSTORMS WILL RETURN DURING THE WEEKEND AHEAD OF A COLD FRONT.
COOL AND DRY HIGH PRESSURE WILL BUILD INTO THE AREA EARLY NEXT WEEK
WITH NEAR RECORD LOWS FORECAST FOR MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...LARGE UPPER LOW CLEARLY EVIDENT ON WV
IMAGERY CENTERED OVER VA WILL CONTINUE TO IMPACT THE SYNOPTIC REGIME
TODAY...ALTHOUGH WITH A GRADUALLY WEAKENING EFFECT.
AMPLE SUNSHINE THIS MORNING HAS ALLOWED TEMPS TO SOAR QUICKLY...AND
SIGNIFICANT ADJUSTMENTS HAVE BEEN MADE TO THE HOURLY CURVE...FORCING
MINOR UPTICKS IN FORECAST HIGHS FOR TODAY. ANTICIPATE MANY PLACES
WILL REACH WELL INTO THE 70S TODAY AWAY FROM THE IMMEDIATE
COAST...APPROACHING 80 IN THE SW PEE DEE ZONES. WITH UPPER LOW STILL
KEEPING ITS BROAD INFLUENCE OVERHEAD...LOW LEVEL AND MID-LEVEL LAPSE
RATES WILL BE RATHER STEEP TODAY...AND ANTICIPATE INCREASING DIURNAL
CONVECTION IN THE FORM OF AFTN CU. WHILE LOW DRIFTS NE THROUGH THE
DAY...500MB TEMPS SLOWLY RISE WHICH FORCES SLOWLY WEAKENING LAPSE
RATES AND THIS WILL INHIBIT MUCH IN THE WAY OF SHOWER/TSTM CHANCES.
HIGH RES WRF/HRRR KEEP THE AREA DRY TODAY...BUT HAVE CONTINUED SCHC
POP IN THE FAR WEST AND NORTH FOR ISOLATED COVERAGE DUE TO PROXIMITY
TO COOLER UPPER LEVEL TEMPS. GUIDANCE DEPICTING 300-700 J/KG OF
SBCAPE ACROSS THESE AREAS THIS AFTN WHICH COULD BE ENOUGH TO DRIVE
AN UPDRAFT STRONGLY ENOUGH TO OBTAIN CHARGE SEPARATION AND
LIGHTNING...BUT THIS IS ONLY POSSIBLE WHERE MAX TEMPS REACH 76 OR
HIGHER. AT THE SAME TIME...WITH WESTERLY STEERING FLOW...ANY STORMS
THAT DEVELOP N/W OF THE AREA MAY SLIP INTO THE CWA AS WELL...HENCE
MAINTAINING THE SCHC POP.
CONVECTION WILL WANE RAPIDLY WITH LOSS OF HEATING...AND ALTHOUGH
MODERATE RADIATIONAL COOLING IS EXPECTED...MINS WILL BE A LITTLE
WARMER THAN LAST NIGHT...FALLING INTO THE MID 50S INLAND...UPPER 50S
AT THE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...DEEP W-NW FLOW AND SUBSIDENCE ON THE BACK
END OF DEPARTING LOW PRESSURE SYSTEM WILL AID IN PRODUCING PLENTY
OF SUNSHINE AND WARM TEMPS ON THURS AND FRI. MODELS ARE HINTING AT
SOME CU DEVELOPMENT ALONG SEA BREEZE BOUNDARY THURS AFTN BUT NO
PCP EXPECTED. WEAK HIGH PRESSURE AT THE SURFACE AND RIDGING ALOFT
THURS NIGHT INTO EARLY FRI WILL PROVIDE FURTHER DRYING ESPECIALLY
THROUGH THE MID LEVELS AS WELL AS INCREASED WARMING WITH TEMPS
REACHING INTO THE MID 80S...SEVERAL DEGREES ABOVE NORMAL.
BY LATE FRI INTO SATURDAY SOUTHWESTERLY RETURN FLOW WILL INCREASE
AS MID TO UPPER TROUGH PUSHES A COLD FRONT EAST REACHING CLOSER TO
THE CAROLINAS. MOISTURE THROUGH THE COLUMN WILL INCREASE AS PCP
WATER VALUES REACH UP CLOSE TO 1.5 INCHES BY FRI EVENING. WILL
CONTINUE TO INCLUDE SLIGHT CHC POPS ASSOCIATED WITH SEA BREEZE
CONVERGENCE FRI AFTN BUT WILL SEE INCREASE IN CLOUDS AND CHC OF
SHWRS LATE FRI INTO SATURDAY MORNING IN INCREASINGLY WARM MOIST
SOUTHERLY FLOW.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...MID TO UPPER TROUGH WILL PUSH COLD FRONT EAST
THROUGH THE CAROLINAS ON SATURDAY CROSSING OUR LOCAL CWA ON
SUNDAY. INCREASING WARM AND MOIST SOUTHERLY FLOW COMBINED WITH
BETTER UPPER DYNAMICS WILL INCREASE CHC OF SHWRS/TSTMS SAT AND
SUNDAY. EXPECT BETTER COVERAGE INLAND ON SATURDAY AND CLOSER TO
THE COAST ON SUNDAY JUST AHEAD AND ALONG COLD FRONT BEFORE IT
SHIFTS OFF THE COAST BY SUN AFTN. PCP WATER VALUES INCREASE UP
AROUND 1.5 INCHES INLAND ON SATURDAY AND EXPECT BETTER COVERAGE AS
SEA BREEZE BOUNDARY PUSHES INLAND. MODELS SHOW SURGE OF MOISTURE
THROUGH EARLY SUNDAY IN 45 LLJ JUST AHEAD OF COLD FRONT. PCP WATER
VALUES INCREASE UP AROUND 1.75 INCHES...ESPECIALLY CLOSER TO THE
COAST ON SUNDAY AS STEERING FLOW SHIFTS AROUND FROM SW TO WEST AS
COLD FRONT MOVES THROUGH.
VERY DRY AND UNSEASONABLY COOL AIR WILL MAKE ITS WAY IN BEHIND
COLD FRONT LATE SUNDAY THROUGH EARLY NEXT WEEK. BEST CAA WILL COME
OVERNIGHT SUNDAY INTO MONDAY IN DEEP NORTHERLY FLOW. GFS SHOWS 850
TEMPS PLUMMETING LATE SUNDAY THROUGH MONDAY BOTTOMING OUT EARLY
TUES BEFORE REBOUNDING. VALUES UP NEAR 14C SAT AFTN DROP DOWN
CLOSE TO 1 C THROUGH EARLY TUES. EXPECT TEMPS UP IN THE 80S WITH
DEWPOINT TEMPS IN THE MID 60S ON SAT INTO EARLY SUNDAY AHEAD OF
COLD FRONT. BY MONDAY TEMPS WILL BE HARD PRESSED TO MAKE IT INTO
THE 70S ALTHOUGH MAY SUNSHINE SHOULD HELP THEM ALONG. DEWPOINT
TEMPS WILL DROP INTO THE 40S AND MAY SEE 30S INLAND. BETTER CAA
SUNDAY NIGHT WILL BRING OVERNIGHT LOWS DOWN CLOSER TO 50 BUT
MONDAY NIGHT HIGH PRESSURE WILL BE NEARLY OVERHEAD WITH MORE IDEAL
RADIATIONAL COOLING CONDITIONS TO HELP BRING TEMPS DOWN INTO THE
40S. MAY SEE TEMPS FLIRT WITH RECORD LOWS MONDAY NIGHT INTO EARLY
TUES. AFTER A COLD START TUES MORNING TEMPS WILL REBOUND TO AROUND
70 WITH PLENTY OF SUNSHINE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS CU BEGINNING TO DEVELOP
OVER THE CWA WITH DAYTIME HEATING. EXPECT THIS TREND TO CONTINUE
THRU THE AFTN WITH SCT CLOUDS 4-5KFT AND SOUTHWEST WINDS 10-15 KTS.
HAVE REMOVED VCSH FOR KLBT AS LATEST HRRR RUNS KEEP ALL SHOWER
ACTIVITY WELL NORTH OF OUR AREA...AND LATEST SATELLITE SHOWS THAT
STILL ONLY SHALLOW CU PRESENT IN THE VICINITY. CLOUD COVER
DIMINISHES TONIGHT... BUT ENHANCED LOW-LEVEL WINDS LIKELY WILL LIMIT
FOG DEVELOPMENT. IT APPEARS PATCHY FOG IS MOST LIKELY AT
KFLO/KLBT...AS THE NEAR SFC WINDS WEAKEN AFTER 06Z AND THE MODEL
SOUNDINGS DEPICT BETTER RADIATIONAL COOLING. CONFIDENCE IS STILL
FAIRLY LOW...BUT ADDED TEMPO MVFR VSBYS FOR THE INLAND TERMS IN THE
09-12Z TIME FRAME. EXPECT VFR CONDITIONS AGAIN ON THURSDAY WITH W-SW
WINDS AOB 10 KTS.
EXTENDED OUTLOOK...MVFR/TEMPO IFR IN MORNING FOG FRIDAY. CHANCE OF
SHOWERS SATURDAY AND SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...BROAD LOW PRESSURE TO THE NW OF THE WATERS
WILL KEEP SW WINDS ONGOING THROUGH THE PERIOD...ALTHOUGH A SLIGHT
BACKING TO S/SW WILL OCCUR IN THE NEAR SHORE WATERS THIS AFTN DUE TO
A DEVELOPING SEA BREEZE. WINDS SPEEDS WILL ALSO BE IMPACTED BY THIS
SEA BREEZE...BEING 10-15 KTS ACROSS MOST OF THE WATERS...BUT GUSTING
TO 20 KTS WITHIN THE SEA BREEZE AFFECTED AREAS. SEAS WILL BECOME
INCREASINGLY WIND-WAVE DOMINATED THANKS TO THE DECREASING EASTERLY
SWELL TODAY...WHICH WILL CREATE SHORTENING PERIODS. EXPECT
PREDOMINANTLY 2-4 FT SEAS THROUGH TONIGHT...WITH A 10 SEC EASTERLY
SWELL AND 5 SEC SW WIND WAVE COMPRISING THE SPECTRUM.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...DEPARTING LOW PRESSURE SYSTEM WILL LEAVE
BEHIND WEAK HIGH PRESSURE OVER THE LOCAL WATERS ON THURSDAY. A
WEAK RETURN FLOW ON THURS WILL INCREASE THROUGH FRIDAY AS HIGH
PRESSURE SHIFTS OFF SHORE AND COLD FRONT APPROACHES THE CAROLINAS
FROM THE WEST. WINDS WILL GENERALLY BE OUT OF THE SOUTHWEST 10 TO
15 KTS THROUGH THURS INTO FRI AND MAY INCREASE TO A SOLID 15 KTS
BY FRI NIGHT AS GRADIENT BEGINS TO TIGHTEN. SEAS WILL DIMINISH
SLIGHTLY THURS INTO FRI REMAINING AROUND 3 FT OR LESS THROUGH MOST
OF THE PERIOD.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...GRADIENT WILL TIGHTEN WITH INCREASING
SOUTHERLY FLOW THROUGH SAT AHEAD OF APPROACHING COLD FRONT. A
PERSISTENT SOUTHERLY PUSH UP AROUND 15 KTS WILL DRIVE SEAS UP
THROUGH SATURDAY BUT A SHARPER RISE WILL OCCUR SAT NIGHT AS COLD
FRONT DRAWS CLOSER AND WINDS INCREASE UP TO 20 KTS. EXPECT SEAS TO
RISE TO NEAR SCA THRESHOLDS BY SUNDAY MORNING JUST AHEAD OF COLD
FRONT. WINDS AND SEAS MAY DIMINISH SLIGHTLY AS THE WINDS VEER
AROUND BEHIND COLD FRONT THROUGH LATE SUNDAY BUT A SURGE SUN NIGHT
IN DECENT CAA WILL PUSH SEAS UP AGAIN JUST NEAR SCA THRESHOLDS.
NEAR SHORE SEAS WILL BE GREATEST SAT NIGHT INTO EARLY SUNDAY IN
SOUTHERLY FLOW AHEAD OF FRONT BUT SEAS IN THE OUTER WATERS MAY BE
GREATER THROUGH EARLY NEXT WEEK IN COLD SURGE BEHIND FRONT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...BJR/JDW
MARINE...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1250 PM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE
REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL
NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD
FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1050 AM WEDNESDAY...
MORNING UPDATE AS OF 1050 AM EDT: CURRENT SATELLITE SHOWS A
VORTICITY MAX EMBEDDED WITHIN THE LARGER CLOSED LOW SLOWLY DRIFTING
SE ACROSS ERN WVA. THE LEADING EDGE OF RAIN AHEAD OF THIS FEATURE IS
NOW APPROACHING OUR NW ZONES. LATEST HRRR HAS A DECENT HANDLE ON
THIS RAIN AND TIMING...AND SHOWS IT MOVING ACROSS OUR NORTHERN ZONES
WHILE DIMINISHING IN COVERAGE THROUGH EARLY/MID AFTERNOON. MEANWHILE
ADDITIONAL CONVECTIVE CELLS ARE SHOWN IN THE HRRR DEVELOPING ACROSS
THE FOOTHILLS DURING THE EARLY AFTERNOON THEN MOVING EASTWARD ACROSS
OUR PIEDMONT ZONES THROUGH 00Z. LATEST VIS SATELLITE SHOWS THE BEST
OPPORTUNITY FOR SUNSHINE AND SFC HEATING ACROSS THE SOUTHERN HALF OF
OUR CWA...THUS LENDING SUPPORT TO THE MODEL DEPICTION OF CONVECTIVE
CELL DEVELOPMENT LATER THIS AFTERNOON. HOWEVER...FORECAST SOUNDINGS
FOR LATER TODAY SUGGEST MID AND UPPER LEVEL WARMING AS THE UPPER LOW
LIFTS NE...AND SHOULD LIMIT OVERALL CAPE AND TSTM/SEVERE POTENTIAL.
IF VIGOROUS TSTM UPDRAFTS CAN DEVELOP...CAN`T RULE OUT SOME SMALL
HAIL AND PERHAPS BRIEF/ISOLATED STRONG WIND GUSTS WITH ANY OF THE
MORE POTENT CELLS.
OTHERWISE...WITH EXTENSIVE CLOUDS AND LIGHT RAIN ACROSS OUR NORTHERN
ZONES...TEMPS HAVE BEEN SLOWER TO RISE THERE...SO WILL MAKE A FEW
SUBTLE DOWNWARD TWEAKS THERE FOR AFTERNOON TEMPS. LOOK FOR HIGHS
TODAY TO RANGE FROM THE UPPER 60S NORTH TO MID 70S SOUTH.
PREV NEAR TERM DISC ISSUED 310 AM EDT:
ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED
TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING
TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY.
FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW
PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC
SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND
WRN PIEDMONT. THE MID-UPPER LEVEL LOW THAT HAS PLAGUED THE REGION
FOR DAYS IS LOCATED AROUND RNK EARLY THIS MORNING... AND IS EXPECTED
TO DRIFT TOWARD THE NNE ALONG THE ERN SLOPES OF THE APPALACHIANS
INTO PA TONIGHT. ABOVE-NORMAL PRECIP WATER WILL CONTINUE TO ROTATE
ABOUT THE NEARLY STACKED CYCLONE... AND MODELS SHOW OVERALL PRECIP
WATER INCREASING FROM JUST UNDER AN INCH THIS MORNING TO NEARLY 1.2
INCHES -- CLOSE TO 150% OF NORMAL -- OVER CENTRAL/ERN NC THIS
AFTERNOON. WITH LOW LEVEL WARM AIR ADVECTION AND THE POCKET OF
SLIGHTLY COOLER MID LEVEL TEMPS OVER NRN/WRN NC... EXPECT THE COLUMN
TO DESTABILIZE BY AFTERNOON... AND BOTH THE NAM AND RAP MODELS SHOW
MLCAPE INCREASING TO 600-1200 J/KG LATER TODAY SPREADING IN FROM THE
SW. AS THE LOW ALOFT LIFTS AWAY FROM NC... MID LEVEL FLOW
STRENGTHENS QUICKLY FROM LESS THAN 20 KTS EARLY THIS MORNING TO
35-40 KTS FROM THE W AND WNW THIS AFTERNOON... AND THIS SHOULD
FOSTER STORM ORGANIZATION DESPITE THE MARGINAL INSTABILITY. DYNAMIC
SUPPORT FROM VORTICITY LOBES ROTATING AROUND THE LOW AS WELL AS A
QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A NORTHWESTERLY 50-KT
UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD ALSO ENCOURAGE STORM
DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED SHOWERS FINISH THEIR
JOURNEY THROUGH CENTRAL NC THIS MORNING... EXPECTED SCATTERED
SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE HIGHER TERRAIN OF NW
NC INTO THE TRIAD REGION... THEN INCREASING IN COVERAGE AS THEY
PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC DURING THE
AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC WRF. GIVEN
THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD BECOME STRONG
WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH WILL DEPEND
ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND THIS IN
TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD COVER
PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE CLOUDS AND
SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND QUICKLY RISING
CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS. EXPECT HIGHS
FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE AND FACTORING
IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE MEAGER DYNAMIC
SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID LEVEL LOW... AND
WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL AFTER NIGHTFALL
ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL FLOW AND DRYING...
SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT... FOLLOWED BY GRADUAL
CLEARING WEST TO EAST. LOWS 53-58.
FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW
ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS
FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL
PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE
SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW
AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE
WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO
MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND
RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH
MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 AM WEDNESDAY...
SPLIT FLOW PATTERN OVER THE CONUS LATE THIS WEEK WILL BECOME
DOMINATED BY THE NORTHERN STREAM BY THIS WEEKEND AS A STRONG
SHORTWAVE BEGINS TO CARVE OUT A DEEP TROUGH OVER THE EASTERN US.
AHEAD OF THIS SYSTEM...RIDGING OVER OUR REGION WILL WEAKEN AS A LEAD
SHORTWAVE MOVES THROUGH THE MIDWEST STATES. THE ASSOCIATED FRONTAL
ZONE WILL MOVE SLOWLY TO THE EAST AND APPROACH THE APPALACHIANS
SATURDAY. THE MORE UNSTABLE WARM SECTOR AIRMASS WILL BE WEST OF
THE MOUNTAINS ON FRIDAY...ALTHOUGH FORECAST SOUNDINGS SUGGEST MLCAPE
MAY REACH 500-1000 J/KG FRIDAY AFTERNOON AS THE UPPER RIDGE
WEAKENS. DEEP LAYER SOUTHWESTERLY FLOW SHOULD BE RELATIVELY
WEAK...MAKING IT DIFFICULT FOR MUCH MORE THAN A FEW ISOLATED STORMS
TO MOVE INTO THE WESTERN PIEDMONT. FRIDAY WILL BE THE WARMEST DAY
OF THE PERIOD WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES. LOW LEVEL
THICKNESSES SURPASSING 1390M AND A SOUTHWESTERLY WIND SUGGEST HIGHS
IN THE LOW TO MID 80S. LOWS FRIDAY NIGHT IN THE LOW TO MID 60S.
GRADUAL HEIGHT FALLS AHEAD OF THE AFOREMENTIONED UPPER TROUGH MOVING
SOUTH OUT OF CANADA WILL HELP TO SHARPEN THE LEE TROUGH SATURDAY AS
A THE COLD FRONT APPROACHES FROM THE WEST. WITH WEAK TO MODERATE
INSTABILITY POSSIBLE...DEPENDING ON THE AMOUNT REGIONAL CLOUD COVER
SATURDAY MORNING....AND DEEP LAYER SHEAR INCREASING TO AROUND
30KT...THERE WILL BE A BETTER CHANCE OF STRONG STORMS SATURDAY
AFTERNOON. HIGHS 76-83 WEST TO EAST. EVEN WITH THE LOSS OF HEATING
SATURDAY NIGHT...SOME CONVECTION SHOULD STILL BE ABLE TO
PERSIST AS THE LEAD FRONTAL ZONE MOVES INTO CENTRAL NC. WILL
MAINTAIN A CHANCE POP THROUGH THE OVERNIGHT HOURS...WITH LOWS IN THE
LOW TO MID 60S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 315 AM WEDNESDAY...
THE COLD FRONT CROSSING THE AREA SATURDAY NIGHT SHOULD EFFECTIVELY
SHIFT TO THE COASTAL PLAIN SUNDAY MORNING...WHILE A SECONDARY AND
STRONGER POLAR FRONT SWINGS INTO THE AREA FROM THE NORTHWEST.
CHANCES OF PRECIP WILL BE PRIMARILY FOCUSED OVER THE COASTAL PLAIN
WHERE ANY APPRECIABLE INSTABILITY WOULD BE MORE LIKELY. HIGHS BEGIN
THEIR MORE SIGNIFICANT DOWNWARD TREND SUNDAY AND PARTICULARLY MONDAY
AS THE AFOREMENTIONED POLAR FRONT CROSSES THE AREA AND A DEEP UPPER
TROUGH DEVELOPS OVER THE EASTERN US. HIGHS IN THE MID 70S SUNDAY
WILL FALL WELL BELOW NORMAL INTO THE MID TO UPPER 60S MONDAY AND
TUESDAY. THERE IS MEDIUM TO HIGH CONFIDENCE IN THESE BELOW NORMAL
TEMPS AND DRY CONDITIONS DURING THE FIRST PART OF NEXT WEEK..
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1250 PM WEDNESDAY...
CURRENT RGNL SAT/RADAR SHOWING EXTENSIVE CLOUD COVER...BUT NOT MUCH
IN THE WAY OF PRECIP AFFECTING OUR TAFS SITES ATTM. MOST CA MODELS
STILL INDICATE SCATTERED SHOWERS DEVELOPING AS THE AFTERNOON
PROGRESSES...AND THIS SEEMS REASONABLE GIVEN THE UPPER IMPULSE TO
OUR NORTH. WHILE THERE ARE SOME SCAT CLOUDS BELOW 3KFT...CIGS ARE
ALL VFR ACROSS CENTRAL NC ATTM. VFR CONDITIONS EXPECTED TO CONTINUE
OUTSIDE OF SHOWER/TSTM ACTIVITY...WHILE MVFR CIGS AND VSBY WILL BE
POSSIBLE IN AND NEAR SHOWERS/TSTMS. PRECIP COVERAGE EXPECTED TO
DIMINISH AFT 04Z THIS EVENING WITH VFR CONDITIONS EXPECTED MOST
LOCATIONS OVERNIGHT. HOWEVER WITH LITTLE CHANGE IN DWPTS AND PARTIAL
CLEARING...FORECAST SOUNDINGS HINT AT SOME PATCHY FOG...PARTICULARLY
NEAR AND NORTH OF KRDU.
LOOKING BEYOND 12Z TONIGHT: VFR CONDITIONS SHOULD DOMINATE INTO
SATURDAY MORNING WITH HIGH PRESSURE STRETCHING OVER THE SOUTHEAST
UNITED STATES. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF
SUB-VFR CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...NP/HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...NP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1050 AM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE
REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL
NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD
FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1050 AM WEDNESDAY...
MORNING UPDATE AS OF 1050 AM EDT: CURRENT SATELLITE SHOWS A
VORTICITY MAX EMBEDDED WITHIN THE LARGER CLOSED LOW SLOWLY DRIFTING
SE ACROSS ERN WVA. THE LEADING EDGE OF RAIN AHEAD OF THIS FEATURE IS
NOW APPROACHING OUR NW ZONES. LATEST HRRR HAS A DECENT HANDLE ON
THIS RAIN AND TIMING...AND SHOWS IT MOVING ACROSS OUR NORTHERN ZONES
WHILE DIMINISHING IN COVERAGE THROUGH EARLY/MID AFTERNOON. MEANWHILE
ADDITIONAL CONVECTIVE CELLS ARE SHOWN IN THE HRRR DEVELOPING ACROSS
THE FOOTHILLS DURING THE EARLY AFTERNOON THEN MOVING EASTWARD ACROSS
OUR PIEDMONT ZONES THROUGH 00Z. LATEST VIS SATELLITE SHOWS THE BEST
OPPORTUNITY FOR SUNSHINE AND SFC HEATING ACROSS THE SOUTHERN HALF OF
OUR CWA...THUS LENDING SUPPORT TO THE MODEL DEPICTION OF CONVECTIVE
CELL DEVELOPMENT LATER THIS AFTERNOON. HOWEVER...FORECAST SOUNDINGS
FOR LATER TODAY SUGGEST MID AND UPPER LEVEL WARMING AS THE UPPER LOW
LIFTS NE...AND SHOULD LIMIT OVERALL CAPE AND TSTM/SEVERE POTENTIAL.
IF VIGOROUS TSTM UPDRAFTS CAN DEVELOP...CAN`T RULE OUT SOME SMALL
HAIL AND PERHAPS BRIEF/ISOLATED STRONG WIND GUSTS WITH ANY OF THE
MORE POTENT CELLS.
OTHERWISE...WITH EXTENSIVE CLOUDS AND LIGHT RAIN ACROSS OUR NORTHERN
ZONES...TEMPS HAVE BEEN SLOWER TO RISE THERE...SO WILL MAKE A FEW
SUBTLE DOWNWARD TWEAKS THERE FOR AFTERNOON TEMPS. LOOK FOR HIGHS
TODAY TO RANGE FROM THE UPPER 60S NORTH TO MID 70S SOUTH.
PREV NEAR TERM DISC ISSUED 310 AM EDT:
ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED
TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING
TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY.
FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW
PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC
SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND
WRN PIEDMONT. THE MID-UPPER LEVEL LOW THAT HAS PLAGUED THE REGION
FOR DAYS IS LOCATED AROUND RNK EARLY THIS MORNING... AND IS EXPECTED
TO DRIFT TOWARD THE NNE ALONG THE ERN SLOPES OF THE APPALACHIANS
INTO PA TONIGHT. ABOVE-NORMAL PRECIP WATER WILL CONTINUE TO ROTATE
ABOUT THE NEARLY STACKED CYCLONE... AND MODELS SHOW OVERALL PRECIP
WATER INCREASING FROM JUST UNDER AN INCH THIS MORNING TO NEARLY 1.2
INCHES -- CLOSE TO 150% OF NORMAL -- OVER CENTRAL/ERN NC THIS
AFTERNOON. WITH LOW LEVEL WARM AIR ADVECTION AND THE POCKET OF
SLIGHTLY COOLER MID LEVEL TEMPS OVER NRN/WRN NC... EXPECT THE COLUMN
TO DESTABILIZE BY AFTERNOON... AND BOTH THE NAM AND RAP MODELS SHOW
MLCAPE INCREASING TO 600-1200 J/KG LATER TODAY SPREADING IN FROM THE
SW. AS THE LOW ALOFT LIFTS AWAY FROM NC... MID LEVEL FLOW
STRENGTHENS QUICKLY FROM LESS THAN 20 KTS EARLY THIS MORNING TO
35-40 KTS FROM THE W AND WNW THIS AFTERNOON... AND THIS SHOULD
FOSTER STORM ORGANIZATION DESPITE THE MARGINAL INSTABILITY. DYNAMIC
SUPPORT FROM VORTICITY LOBES ROTATING AROUND THE LOW AS WELL AS A
QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A NORTHWESTERLY 50-KT
UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD ALSO ENCOURAGE STORM
DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED SHOWERS FINISH THEIR
JOURNEY THROUGH CENTRAL NC THIS MORNING... EXPECTED SCATTERED
SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE HIGHER TERRAIN OF NW
NC INTO THE TRIAD REGION... THEN INCREASING IN COVERAGE AS THEY
PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC DURING THE
AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC WRF. GIVEN
THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD BECOME STRONG
WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH WILL DEPEND
ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND THIS IN
TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD COVER
PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE CLOUDS AND
SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND QUICKLY RISING
CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS. EXPECT HIGHS
FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE AND FACTORING
IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE MEAGER DYNAMIC
SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID LEVEL LOW... AND
WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL AFTER NIGHTFALL
ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL FLOW AND DRYING...
SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT... FOLLOWED BY GRADUAL
CLEARING WEST TO EAST. LOWS 53-58.
FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW
ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS
FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL
PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE
SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW
AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE
WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO
MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND
RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH
MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 AM WEDNESDAY...
SPLIT FLOW PATTERN OVER THE CONUS LATE THIS WEEK WILL BECOME
DOMINATED BY THE NORTHERN STREAM BY THIS WEEKEND AS A STRONG
SHORTWAVE BEGINS TO CARVE OUT A DEEP TROUGH OVER THE EASTERN US.
AHEAD OF THIS SYSTEM...RIDGING OVER OUR REGION WILL WEAKEN AS A LEAD
SHORTWAVE MOVES THROUGH THE MIDWEST STATES. THE ASSOCIATED FRONTAL
ZONE WILL MOVE SLOWLY TO THE EAST AND APPROACH THE APPALACHIANS
SATURDAY. THE MORE UNSTABLE WARM SECTOR AIRMASS WILL BE WEST OF
THE MOUNTAINS ON FRIDAY...ALTHOUGH FORECAST SOUNDINGS SUGGEST MLCAPE
MAY REACH 500-1000 J/KG FRIDAY AFTERNOON AS THE UPPER RIDGE
WEAKENS. DEEP LAYER SOUTHWESTERLY FLOW SHOULD BE RELATIVELY
WEAK...MAKING IT DIFFICULT FOR MUCH MORE THAN A FEW ISOLATED STORMS
TO MOVE INTO THE WESTERN PIEDMONT. FRIDAY WILL BE THE WARMEST DAY
OF THE PERIOD WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES. LOW LEVEL
THICKNESSES SURPASSING 1390M AND A SOUTHWESTERLY WIND SUGGEST HIGHS
IN THE LOW TO MID 80S. LOWS FRIDAY NIGHT IN THE LOW TO MID 60S.
GRADUAL HEIGHT FALLS AHEAD OF THE AFOREMENTIONED UPPER TROUGH MOVING
SOUTH OUT OF CANADA WILL HELP TO SHARPEN THE LEE TROUGH SATURDAY AS
A THE COLD FRONT APPROACHES FROM THE WEST. WITH WEAK TO MODERATE
INSTABILITY POSSIBLE...DEPENDING ON THE AMOUNT REGIONAL CLOUD COVER
SATURDAY MORNING....AND DEEP LAYER SHEAR INCREASING TO AROUND
30KT...THERE WILL BE A BETTER CHANCE OF STRONG STORMS SATURDAY
AFTERNOON. HIGHS 76-83 WEST TO EAST. EVEN WITH THE LOSS OF HEATING
SATURDAY NIGHT...SOME CONVECTION SHOULD STILL BE ABLE TO
PERSIST AS THE LEAD FRONTAL ZONE MOVES INTO CENTRAL NC. WILL
MAINTAIN A CHANCE POP THROUGH THE OVERNIGHT HOURS...WITH LOWS IN THE
LOW TO MID 60S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 315 AM WEDNESDAY...
THE COLD FRONT CROSSING THE AREA SATURDAY NIGHT SHOULD EFFECTIVELY
SHIFT TO THE COASTAL PLAIN SUNDAY MORNING...WHILE A SECONDARY AND
STRONGER POLAR FRONT SWINGS INTO THE AREA FROM THE NORTHWEST.
CHANCES OF PRECIP WILL BE PRIMARILY FOCUSED OVER THE COASTAL PLAIN
WHERE ANY APPRECIABLE INSTABILITY WOULD BE MORE LIKELY. HIGHS BEGIN
THEIR MORE SIGNIFICANT DOWNWARD TREND SUNDAY AND PARTICULARLY MONDAY
AS THE AFOREMENTIONED POLAR FRONT CROSSES THE AREA AND A DEEP UPPER
TROUGH DEVELOPS OVER THE EASTERN US. HIGHS IN THE MID 70S SUNDAY
WILL FALL WELL BELOW NORMAL INTO THE MID TO UPPER 60S MONDAY AND
TUESDAY. THERE IS MEDIUM TO HIGH CONFIDENCE IN THESE BELOW NORMAL
TEMPS AND DRY CONDITIONS DURING THE FIRST PART OF NEXT WEEK..
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM WEDNESDAY...
SUB-VFR CIGS DEVELOPED OVERNIGHT AT INT/GSO -- IFR AT INT AND MVFR
AT GSO -- WHILE VFR CONDITIONS HAVE DOMINATED AT RDU/RWI/FAY. MVFR
CONDITIONS SHOULD HOLD AT INT/GSO FOR A FEW MORE HOURS THIS MORNING
BEFORE LIFTING TO VFR BY AROUND 16Z... WHILE VFR CONDITIONS SHOULD
PERSIST AT RDU/RWI/FAY THROUGH THE MORNING. ISOLATED SHOWERS NEAR
RDU/RWI THROUGH 14Z SHOULD HAVE NO ADVERSE IMPACT. SCATTERED SHOWERS
AND STORMS ARE EXPECTED TO DEVELOP WEST OF THE TRIAD TOWARD MIDDAY
AND AFFECT INT/GSO MAINLY FROM 16Z-20Z... RDU MAINLY FROM 17Z-21Z...
AND RWI/FAY MAINLY FROM 19Z-23Z AS THE SHOWERS/STORMS MOVE ESE
ACROSS THE AREA AND INCREASE IN COVERAGE. A PERIOD OF MVFR-IFR
CIGS/VSBYS IN AND NEAR SHOWERS/STORMS IS LIKELY... OTHERWISE VFR
CONDITIONS ARE EXPECTED TO DOMINATE THROUGH TONIGHT WITH SKIES
PARTIALLY CLEARING LATE.
LOOKING BEYOND 12Z TONIGHT: VFR CONDITIONS SHOULD DOMINATE INTO
SATURDAY MORNING WITH HIGH PRESSURE STRETCHING OVER THE SOUTHEAST
UNITED STATES. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF
SUB-VFR CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY.
-GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...NP/HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE
REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL
NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD
FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 310 AM WEDNESDAY...
ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED
TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING
TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY.
FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW
PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC
SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND
WRN PIEDMONT. MID LEVEL DPVA COMBINED WITH AN AREA OF ENHANCED
MOISTURE AND LOW LEVEL CONVERGENCE IS SUPPORTING A BATCH OF SHOWERS
TRACKING NE THROUGH CENTRAL NC EARLY THIS MORNING. THE MID-UPPER
LEVEL LOW THAT HAS PLAGUED THE REGION FOR DAYS IS LOCATED AROUND RNK
EARLY THIS MORNING... AND IS EXPECTED TO DRIFT TOWARD THE NNE ALONG
THE ERN SLOPES OF THE APPALACHIANS INTO PA TONIGHT. ABOVE-NORMAL
PRECIP WATER WILL CONTINUE TO ROTATE ABOUT THE NEARLY STACKED
CYCLONE... AND MODELS SHOW OVERALL PRECIP WATER INCREASING FROM JUST
UNDER AN INCH THIS MORNING TO NEARLY 1.2 INCHES -- CLOSE TO 150% OF
NORMAL -- OVER CENTRAL/ERN NC THIS AFTERNOON. WITH LOW LEVEL WARM
AIR ADVECTION AND THE POCKET OF SLIGHTLY COOLER MID LEVEL TEMPS OVER
NRN/WRN NC... EXPECT THE COLUMN TO DESTABILIZE BY AFTERNOON... AND
BOTH THE NAM AND RAP MODELS SHOW MLCAPE INCREASING TO 600-1200 J/KG
LATER TODAY SPREADING IN FROM THE SW. AS THE LOW ALOFT LIFTS AWAY
FROM NC... MID LEVEL FLOW STRENGTHENS QUICKLY FROM LESS THAN 20 KTS
EARLY THIS MORNING TO 35-40 KTS FROM THE W AND WNW THIS AFTERNOON...
AND THIS SHOULD FOSTER STORM ORGANIZATION DESPITE THE MARGINAL
INSTABILITY. DYNAMIC SUPPORT FROM VORTICITY LOBES ROTATING AROUND
THE LOW AS WELL AS A QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A
NORTHWESTERLY 50-KT UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD
ALSO ENCOURAGE STORM DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED
SHOWERS FINISH THEIR JOURNEY THROUGH CENTRAL NC THIS MORNING...
EXPECTED SCATTERED SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE
HIGHER TERRAIN OF NW NC INTO THE TRIAD REGION... THEN INCREASING IN
COVERAGE AS THEY PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC
DURING THE AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC
WRF. GIVEN THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD
BECOME STRONG WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH
WILL DEPEND ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND
THIS IN TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD
COVER PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE
CLOUDS AND SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND
QUICKLY RISING CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS.
EXPECT HIGHS FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE
AND FACTORING IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE
MEAGER DYNAMIC SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID
LEVEL LOW... AND WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL
AFTER NIGHTFALL ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL
FLOW AND DRYING... SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT...
FOLLOWED BY GRADUAL CLEARING WEST TO EAST. LOWS 53-58.
FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW
ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS
FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL
PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE
SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW
AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE
WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO
MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND
RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH
MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 315 AM WEDNESDAY...
SPLIT FLOW PATTERN OVER THE CONUS LATE THIS WEEK WILL BECOME
DOMINATED BY THE NORTHERN STREAM BY THIS WEEKEND AS A STRONG
SHORTWAVE BEGINS TO CARVE OUT A DEEP TROUGH OVER THE EASTERN US.
AHEAD OF THIS SYSTEM...RIDGING OVER OUR REGION WILL WEAKEN AS A LEAD
SHORTWAVE MOVES THROUGH THE MIDWEST STATES. THE ASSOCIATED FRONTAL
ZONE WILL MOVE SLOWLY TO THE EAST AND APPROACH THE APPALACHIANS
SATURDAY. THE MORE UNSTABLE WARM SECTOR AIRMASS WILL BE WEST OF
THE MOUNTAINS ON FRIDAY...ALTHOUGH FORECAST SOUNDINGS SUGGEST MLCAPE
MAY REACH 500-1000 J/KG FRIDAY AFTERNOON AS THE UPPER RIDGE
WEAKENS. DEEP LAYER SOUTHWESTERLY FLOW SHOULD BE RELATIVELY
WEAK...MAKING IT DIFFICULT FOR MUCH MORE THAN A FEW ISOLATED STORMS
TO MOVE INTO THE WESTERN PIEDMONT. FRIDAY WILL BE THE WARMEST DAY
OF THE PERIOD WITH PARTLY CLOUDY TO MOSTLY SUNNY SKIES. LOW LEVEL
THICKNESSES SURPASSING 1390M AND A SOUTHWESTERLY WIND SUGGEST HIGHS
IN THE LOW TO MID 80S. LOWS FRIDAY NIGHT IN THE LOW TO MID 60S.
GRADUAL HEIGHT FALLS AHEAD OF THE AFOREMENTIONED UPPER TROUGH MOVING
SOUTH OUT OF CANADA WILL HELP TO SHARPEN THE LEE TROUGH SATURDAY AS
A THE COLD FRONT APPROACHES FROM THE WEST. WITH WEAK TO MODERATE
INSTABILITY POSSIBLE...DEPENDING ON THE AMOUNT REGIONAL CLOUD COVER
SATURDAY MORNING....AND DEEP LAYER SHEAR INCREASING TO AROUND
30KT...THERE WILL BE A BETTER CHANCE OF STRONG STORMS SATURDAY
AFTERNOON. HIGHS 76-83 WEST TO EAST. EVEN WITH THE LOSS OF HEATING
SATURDAY NIGHT...SOME CONVECTION SHOULD STILL BE ABLE TO
PERSIST AS THE LEAD FRONTAL ZONE MOVES INTO CENTRAL NC. WILL
MAINTAIN A CHANCE POP THROUGH THE OVERNIGHT HOURS...WITH LOWS IN THE
LOW TO MID 60S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 315 AM WEDNESDAY...
THE COLD FRONT CROSSING THE AREA SATURDAY NIGHT SHOULD EFFECTIVELY
SHIFT TO THE COASTAL PLAIN SUNDAY MORNING...WHILE A SECONDARY AND
STRONGER POLAR FRONT SWINGS INTO THE AREA FROM THE NORTHWEST.
CHANCES OF PRECIP WILL BE PRIMARILY FOCUSED OVER THE COASTAL PLAIN
WHERE ANY APPRECIABLE INSTABILITY WOULD BE MORE LIKELY. HIGHS BEGIN
THEIR MORE SIGNIFICANT DOWNWARD TREND SUNDAY AND PARTICULARLY MONDAY
AS THE AFOREMENTIONED POLAR FRONT CROSSES THE AREA AND A DEEP UPPER
TROUGH DEVELOPS OVER THE EASTERN US. HIGHS IN THE MID 70S SUNDAY
WILL FALL WELL BELOW NORMAL INTO THE MID TO UPPER 60S MONDAY AND
TUESDAY. THERE IS MEDIUM TO HIGH CONFIDENCE IN THESE BELOW NORMAL
TEMPS AND DRY CONDITIONS DURING THE FIRST PART OF NEXT WEEK..
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1245 AM WEDNESDAY...
LIKELIHOOD IS INCREASING THAT MOST CENTRAL NC TAF SITES WILL SEE VFR
CIGS/VSBYS THROUGH THIS MORNING... ALTHOUGH A BRIEF PERIOD OF IFR
VSBYS IS POSSIBLE AT INT/GSO NEAR AND JUST BEFORE DAYBREAK.
CONSIDERABLE CONVECTIVE-DEBRIS CLOUDINESS FROM YESTERDAY`S SHOWERS
AND STORMS ARE BASED ABOVE 5 THOUSAND FT AGL AND SHOULD CONTINUE TO
OVERSPREAD INT/GSO/RDU THROUGH THE NIGHT... EVENTUALLY REACHING
FAY/RWI AS WELL LATER TODAY. DESPITE THE OTHERWISE-FAVORABLE
CONDITIONS OF LIGHT WINDS AND HIGH HUMIDITY WITH A DAMP GROUND...
THE PRESENCE OF THESE CLOUDS WILL LOWER THE CHANCES OF FOG AND
IFR/LIFR EARLY THIS MORNING. FAY WILL SEE THE FEWEST OF THESE
HIGHER-BASED CLOUDS LATER THAN OTHER SITES... SO FAY HAS THE BEST
CHANCE (BUT STILL LOW) OF SEEING LOW STRATUS DEVELOP. OTHERWISE...
EXPECT VFR CONDITIONS TO DOMINATE MUCH OF TODAY INTO TONIGHT.
SCATTERED SHOWERS AND STORMS ARE EXPECTED TO AFFECT INT/GSO MAINLY
FROM 16Z-20Z... RDU MAINLY FROM 17Z-21Z... AND RWI/FAY MAINLY FROM
19Z-23Z... AND A PERIOD OF MVFR-IFR CIGS/VSBYS IN AND NEAR
SHOWERS/STORMS IS LIKELY.
LOOKING BEYOND 06Z TONIGHT: VFR CLOUDS ARE EXPECTED TO CLEAR OUT
LATE... AND SUB-VFR FOG IS POSSIBLE TONIGHT PRIMARILY 08Z-12Z AT ALL
SITES. OTHERWISE VFR CONDITIONS SHOULD DOMINATE INTO SATURDAY
MORNING. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF SUB-VFR
CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE NORTHWARD AWAY FROM THE
REGION TODAY. WEAK HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL
NOSE WESTWARD INTO THE SOUTHEAST THURSDAY AND FRIDAY... THEN A COLD
FRONT WILL APPROACH FROM THE NORTHWEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 310 AM WEDNESDAY...
ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS/STORMS IS EXPECTED
TODAY WITH SLIGHTLY BELOW-NORMAL HIGHS... BEFORE WE SEE REBOUNDING
TEMPS AND A REPRIEVE FROM RAIN ON THURSDAY.
FOR TODAY/TONIGHT: THE LATEST SURFACE ANALYSIS SHOW BROAD WEAK LOW
PRESSURE OVER NW NC INTO ADJACENT SW VA SURROUNDED BY WEAK CYCLONIC
SURFACE FLOW... FEATURING A DIFFUSE TROUGH THROUGH THE FOOTHILLS AND
WRN PIEDMONT. MID LEVEL DPVA COMBINED WITH AN AREA OF ENHANCED
MOISTURE AND LOW LEVEL CONVERGENCE IS SUPPORTING A BATCH OF SHOWERS
TRACKING NE THROUGH CENTRAL NC EARLY THIS MORNING. THE MID-UPPER
LEVEL LOW THAT HAS PLAGUED THE REGION FOR DAYS IS LOCATED AROUND RNK
EARLY THIS MORNING... AND IS EXPECTED TO DRIFT TOWARD THE NNE ALONG
THE ERN SLOPES OF THE APPALACHIANS INTO PA TONIGHT. ABOVE-NORMAL
PRECIP WATER WILL CONTINUE TO ROTATE ABOUT THE NEARLY STACKED
CYCLONE... AND MODELS SHOW OVERALL PRECIP WATER INCREASING FROM JUST
UNDER AN INCH THIS MORNING TO NEARLY 1.2 INCHES -- CLOSE TO 150% OF
NORMAL -- OVER CENTRAL/ERN NC THIS AFTERNOON. WITH LOW LEVEL WARM
AIR ADVECTION AND THE POCKET OF SLIGHTLY COOLER MID LEVEL TEMPS OVER
NRN/WRN NC... EXPECT THE COLUMN TO DESTABILIZE BY AFTERNOON... AND
BOTH THE NAM AND RAP MODELS SHOW MLCAPE INCREASING TO 600-1200 J/KG
LATER TODAY SPREADING IN FROM THE SW. AS THE LOW ALOFT LIFTS AWAY
FROM NC... MID LEVEL FLOW STRENGTHENS QUICKLY FROM LESS THAN 20 KTS
EARLY THIS MORNING TO 35-40 KTS FROM THE W AND WNW THIS AFTERNOON...
AND THIS SHOULD FOSTER STORM ORGANIZATION DESPITE THE MARGINAL
INSTABILITY. DYNAMIC SUPPORT FROM VORTICITY LOBES ROTATING AROUND
THE LOW AS WELL AS A QUICK SHOT OF ENHANCED UPPER DIVERGENCE WITH A
NORTHWESTERLY 50-KT UPPER JETLET OVER WV/SW VA LATER TODAY SHOULD
ALSO ENCOURAGE STORM DEVELOPMENT AND MAINTENANCE. AFTER THE ISOLATED
SHOWERS FINISH THEIR JOURNEY THROUGH CENTRAL NC THIS MORNING...
EXPECTED SCATTERED SHOWERS AND STORMS TO DEVELOP... FIRST OVER THE
HIGHER TERRAIN OF NW NC INTO THE TRIAD REGION... THEN INCREASING IN
COVERAGE AS THEY PROGRESS THE E AND SE THROUGH CENTRAL AND ERN NC
DURING THE AFTERNOON... AN EVOLUTION DEPICTED WELL BY THE LATEST SPC
WRF. GIVEN THE IMPROVING DEEP LAYER SHEAR... A FEW STORMS COULD
BECOME STRONG WITH SOME 40+ KT GUSTS AND SMALL HAIL... ALTHOUGH MUCH
WILL DEPEND ON EXACTLY HOW UNSTABLE IT BECOMES THIS AFTERNOON... AND
THIS IN TURN WILL DEPEND ON HOW MUCH OF THE COPIOUS MID LEVEL CLOUD
COVER PERSISTS AS WE HEAD TOWARD AFTERNOON. ANY BREAKS IN THESE
CLOUDS AND SUBSEQUENT HEATING SHOULD LEAD TO A RAPID WARM-UP AND
QUICKLY RISING CAPE VALUES GIVEN THE MOISTENING SURFACE DEW POINTS.
EXPECT HIGHS FROM 69 NW TO 76 SE... FOLLOWING STATISTICAL GUIDANCE
AND FACTORING IN YESTERDAY`S TEMPS. WE QUICKLY LOSE ANY OF THE
MEAGER DYNAMIC SUPPORT FOR PRECIP TONIGHT WITH THE DEPARTING MID
LEVEL LOW... AND WE SHOULD LOSE INSTABILITY RATHER RAPIDLY AS WELL
AFTER NIGHTFALL ESPECIALLY WITH AN INCREASING DOWNSLOPE LOW LEVEL
FLOW AND DRYING... SO SHOWER CHANCES SHOULD CUT OFF BY MIDNIGHT...
FOLLOWED BY GRADUAL CLEARING WEST TO EAST. LOWS 53-58.
FOR THURSDAY/THURSDAY NIGHT: THE MID LEVEL LOW HEADS UP ACROSS NEW
ENGLAND WHILE MID LEVEL RIDGING STARTS TO BUILD INTO THE CAROLINAS
FROM THE SW. WEAK SURFACE TROUGHING WILL EXTEND THROUGH THE COASTAL
PLAIN THURSDAY AS OFFSHORE HIGH PRESSURE NOSES WESTWARD INTO THE
SOUTHEAST STATES. EXPECT A DRIER COLUMN WITH DEEP FLOW FROM THE WNW
AND NW OVER CENTRAL NC... AND THIS ALONG WITH OVERALL SUBSIDENCE
WILL LIMIT ANY CONVECTION. WILL STICK WITH DRY WEATHER AND PARTLY TO
MOSTLY SUNNY SKIES. WITH A LOW LEVEL DRY ADIABATIC PROFILE AND
RISING THICKNESSES... EXPECT WARM HIGHS OF 78-84. LOWS 54-61 WITH
MOSTLY CLEAR SKIES THURSDAY NIGHT. -GIH
&&
.SHORT TERM / /...
AS OF 245 PM TUESDAY...
TO BE UPDATED.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 110 PM TUESDAY...
AROUND REX BLOCKING OVER THE WESTERN US...SPLIT FLOW ACROSS THE
EASTERN TWO THIRDS OF THE COUNTRY WILL GRADUALLY TRANSITION TOWARD
NORTHERN STREAM DOMINANCE OWING TO THE AMPLIFICATION OF A VORTEX
INVOF THE SOUTHERN TIP OF HUDSON BAY DURING THE WEEKEND AND EARLY
NEXT WEEK. THE PASSAGE OF A LEAD SHORTWAVE TROUGH THROUGH THE
NORTHEAST ON FRIDAY WILL FIRST SHARPEN A LEE TROUGH OVER WESTERN NC
FRI AFTERNOON...THEN PROPEL A LEAD SURFACE COLD FRONT INTO THE
APPALACHIANS AND CAROLINAS ON SATURDAY. A STRONGER POLAR FRONT
ATTENDING THE AFOREMENTIONED HUDSON BAY VORTEX WILL THEN OVERTAKE
THE LEAD FRONTAL ZONE AND SWEEP ACROSS CENTRAL NC SUNDAY...WITH
CONTINENTAL POLAR HIGH PRESSURE BUILDING IN FOR MON-TUE. AS
SUCH...THE PREVIOUS FORECAST OF CHANCE OF SHOWERS AND STORMS OVER
THE WESTERN PIEDMONT FRI...TRANSITIONING TO SOLID CHANCE AREA-WIDE
SATURDAY THROUGH SUNDAY NEEDS LITTLE ADJUSTMENT. ANY ORGANIZED
CONVECTIVE MODE WOULD BE FAVORED DURING THE WEEKEND...WHEN WARM
SECTOR MID LEVEL FLOW WILL BE MAXIMIZED AROUND 40-50 KTS...WITH
OTHERWISE DISORGANIZED/PULSE MODES UNTIL THEN. TEMPERATURES WILL
CONSEQUENTLY BE VARIABLE...PEAKING IN THE MIDDLE 80S FRI...AND SAT
IN THE COASTAL PLAIN...TRENDING TO THE MID-UPPER 60S IN THE CP HIGH
PRESSURE MON...AND REBOUNDING TO AROUND 70 DEGREES BY TUE.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1245 AM WEDNESDAY...
LIKELIHOOD IS INCREASING THAT MOST CENTRAL NC TAF SITES WILL SEE VFR
CIGS/VSBYS THROUGH THIS MORNING... ALTHOUGH A BRIEF PERIOD OF IFR
VSBYS IS POSSIBLE AT INT/GSO NEAR AND JUST BEFORE DAYBREAK.
CONSIDERABLE CONVECTIVE-DEBRIS CLOUDINESS FROM YESTERDAY`S SHOWERS
AND STORMS ARE BASED ABOVE 5 THOUSAND FT AGL AND SHOULD CONTINUE TO
OVERSPREAD INT/GSO/RDU THROUGH THE NIGHT... EVENTUALLY REACHING
FAY/RWI AS WELL LATER TODAY. DESPITE THE OTHERWISE-FAVORABLE
CONDITIONS OF LIGHT WINDS AND HIGH HUMIDITY WITH A DAMP GROUND...
THE PRESENCE OF THESE CLOUDS WILL LOWER THE CHANCES OF FOG AND
IFR/LIFR EARLY THIS MORNING. FAY WILL SEE THE FEWEST OF THESE
HIGHER-BASED CLOUDS LATER THAN OTHER SITES... SO FAY HAS THE BEST
CHANCE (BUT STILL LOW) OF SEEING LOW STRATUS DEVELOP. OTHERWISE...
EXPECT VFR CONDITIONS TO DOMINATE MUCH OF TODAY INTO TONIGHT.
SCATTERED SHOWERS AND STORMS ARE EXPECTED TO AFFECT INT/GSO MAINLY
FROM 16Z-20Z... RDU MAINLY FROM 17Z-21Z... AND RWI/FAY MAINLY FROM
19Z-23Z... AND A PERIOD OF MVFR-IFR CIGS/VSBYS IN AND NEAR
SHOWERS/STORMS IS LIKELY.
LOOKING BEYOND 06Z TONIGHT: VFR CLOUDS ARE EXPECTED TO CLEAR OUT
LATE... AND SUB-VFR FOG IS POSSIBLE TONIGHT PRIMARILY 08Z-12Z AT ALL
SITES. OTHERWISE VFR CONDITIONS SHOULD DOMINATE INTO SATURDAY
MORNING. AN APPROACHING COLD FRONT WILL BRING A CHANCE OF SUB-VFR
CONDITIONS IN SHOWERS/STORMS SATURDAY AFTERNOON INTO SUNDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT/MWS
LONG TERM...MWS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
358 PM CDT WED MAY 8 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 358 PM CDT WED MAY 8 2013
THE MAIN FOCUS FOR THE REST OF THIS AFTERNOON AND EVENING WILL BE
THE POSSIBILITY OF SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHEAST.
THE MAIN FOCUS FOR TONIGHT AND TOMORROW WILL BE THE POSSIBILITY OF
SHOWERS AND THUNDERSTORMS IN THE WEST.
A COLD FRONT WAS SLOWLY PUSHING SOUTH THIS AFTERNOON ACROSS FAR
SOUTHERN NORTH DAKOTA. THE COLD FRONT WILL BE THE PRIMARY LOCATION
OF ANY SHOWERS OR THUNDERSTORMS THAT DO DEVELOP. AHEAD OF THE
FRONT THE ATMOSPHERE CONTINUES TO DESTABILIZE AS EVIDENCED BY THE
CU FIELD IN VISIBLE SATELLITE. THE 17 UTC RAP PAINTS 400+ J/KG OF
CAPE ACROSS SOUTHERN NORTH DAKOTA. THE 15 UTC HRRR MODEL HAS
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ALONG AND AHEAD OF
THE FRONT LATER THIS AFTERNOON. ONE OF THE MAIN LIMITING FACTORS
ON WHETHER SHOWERS AND THUNDERSTORMS DEVELOP AND HOW WIDESPREAD
THEY BECOME IS THE BROAD SYNOPTIC SCALE SUBSIDENCE BEHIND THE
DEPARTING UPPER LEVEL LOW.
LATE TONIGHT AND TOMORROW MORNING A WEAK UPPER LEVEL SHORTWAVE TROUGH
WILL ENTER EASTERN MONTANA AND WESTERN NORTH DAKOTA. THIS SHORTWAVE
MAY PROVIDE ENOUGH ASCENT ALONG A DEVELOPING SURFACE BAROCLINIC
ZONE IN EASTERN MONTANA AND WESTERN NORTH DAKOTA TO SPARK SOME
ISOLATED RAIN SHOWERS. SURFACE HIGH PRESSURE AND COLD AIR
ADVECTION SHOULD KEEP CENTRAL AND EASTERN NORTH DAKOTA DRY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 358 PM CDT WED MAY 8 2013
THE MAIN FOCUS OF THE EXTENDED PERIOD WILL BE THE COLD FRONT THAT IS
PROGGED TO DROP SOUTH OUT OF SOUTHERN CANADA AND INTO THE NORTHWEST
BY FRIDAY MORNING. THIS FRONT WILL CONTINUE TO MOVE SOUTH OVER THE
AREA...WITH IT MOVING INTO SOUTH DAKOTA BY EARLY SATURDAY MORNING.
THE CONCERN WILL LIE AHEAD OF THIS FRONT...WHERE THUNDERSTORMS MAY
BE POSSIBLE. ACCORDING TO THE 12Z NAM...SURFACE BASED CAPE AHEAD OF
THIS FRONT WILL BE IN THE 500 TO 600 J/KG RANGE...WITH THE 0-6 KM
BULK SHEAR BEING MORE THAN SUFFICIENT FOR AIDING IN THE DEVELOPMENT
OF SEVERE THUNDERSTORMS. ON THE OTHER HAND...THE GFS DEPICTS THE
STRONG 0-6 KM BULK SHEAR...BUT DOES NOT PAINT ANY SURFACE BASED CAPE
NOR MOST UNSTABLE CAPE OVER THE AREA. MOISTURE WILL ALSO BE A
LIMITING FACTOR AS FORECAST DEWPOINTS WILL ONLY BE IN THE 30S AND
40S. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD SHOWER
ACTIVITY AHEAD OF THE FRONT AND THAT IF ANY THUNDERSTORMS THAT DO
DEVELOP WILL REMAIN BELOW THE SEVERE THRESHOLD AND WILL BE OF THE
GARDEN VARIETY TYPE.
AHEAD OF THE AFOREMENTIONED COLD FRONT...TEMPERATURES WILL WARM
WITH THE RETURN FLOW AND BE IN THE 60S AND LOWER 70S. AS THE FRONT
MOVES THROUGH THE AREA...TEMPERATURES WILL RETURN TO BELOW
NORMAL...WITH TEMPERATURES IN THE UPPER 40S TO MID 50S. SATURDAY
NIGHT AND INTO SUNDAY MORNING...THERE IS THE POTENTIAL FOR
TEMPERATURES TO FLIRT WITH THE FREEZING MARK ACROSS MOST OF THE AREA
AND POSSIBLY ENDANGER NEW VEGETATION AND PLANT GROWTH.
THEREAFTER...TEMPERATURES WILL AGAIN WARM SUNDAY AS A WARM FRONT
MOVES EAST AND AN UPPER LEVEL RIDGE BUILDS EAST OVER THE NORTHERN
PLAINS. TEMPERATURES WILL CLIMB ABOVE NORMAL MONDAY WITH HIGHS IN
THE LOW TO MID 80S AS THE RIDGE AXIS MOVES OVERHEAD.
FOR THE REMAINDER OF THE PERIOD (TUESDAY ONWARDS)...QUASIZONAL FLOW
WILL DEVELOP AND TEMPERATURES WILL RETURN TO SEASONAL NORMS. THERE
IS A POSSIBILITY FOR SHOWERS AND THUNDERSTORMS DURING MONDAY
EVENING...HOWEVER THEY ARE NOT EXPECTED TO BECOME SEVERE. SHOWERS
WILL CONTINUE THROUGH EARLY THURSDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 358 PM CDT WED MAY 8 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT ALL
TERMINALS. GUSTY NORTHEAST WINDS UP TO 22 KNOTS WILL CONTINUE THROUGH
AFTERNOON AND EARLY EVENING...DIMINISHING OVER THE NORTHWEST AFTER
SUNSET AND AFTER 06Z AT KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...LTH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1237 AM CDT WED MAY 8 2013
.UPDATE...
ISSUED AT 1237 AM CDT WED MAY 8 2013
LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW THE UPPER LEVEL LOW
CIRCULATION OVER NORTH CENTRAL SOUTH DAKOTA...WITH A SHORTWAVE
TROUGH/ASSOCIATED SURFACE COLD FRONT ENTERING NORTHWEST NORTH DAKOTA
VIA THE NORTHERN BRANCH. LATEST RUC MAINTAINS A DRY FORECAST
OVERNIGHT AND WILL CONTINUE WITH THAT IDEA...AS REGIONAL RADAR SHOWS
THE NEAREST PRECIPITATION AREA IS IN FAR SOUTHEAST NORTH DAKOTA
ASSOCIATED WITH THE UPPER LOW. THIS WILL ROTATE AROUND THE LOW AND
APPROACH OUR SOUTHEAST BORDER BY AROUND 12Z WEDNESDAY. THE CURRENT
FORECAST HAS A SLIGHT CHANCE BY THAT TIME AND NO ADJUSTMENTS NEEDED.
THE COLD FRONT WILL PROGRESS SOUTH OVERNIGHT WITH WINDS SHIFTING TO
THE NORTHEAST. SCT/BKN CLOUDS WILL ACCOMPANY THE FRONTAL PASSAGE BUT
REMAINING DRY.
UPDATE
ISSUED AT 930 PM CDT TUE MAY 7 2013
FORECAST REMAINS VALID. CONVECTION CONTINUES TO DISSIPATE ACROSS
FAR SOUTHEASTERN EMMONS AND FAR SOUTHWESTERN MCINTOSH COUNTIES
WITH THE ONSET OF DARK. THIS AREA OF PRECIPITATION SHOULD BE GONE
BY 04Z. FRONTAL PASSAGE WILL PUSH SOUTH OVERNIGHT INTO WEDNESDAY
MORNING...WITH NORTHEAST WINDS INCREASING TO NEAR 20 MPH BEHIND
THE FROPA AND CONTINUING THROUGH WEDNESDAY DAYTIME. WILL SEE
ANOTHER ROUND OF DIURNAL SHOWERS/ISOLATED THUNDERSTORMS LATE WED
MORNING AND AFTERNOON FAR SOUTH.
UPDATE ISSUED AT 651 PM CDT TUE MAY 7 2013
THE INHERITED FORECAST IS MAINLY ON TRACK. ADJUSTED POPS
ACCORDINGLY BASED ON LATEST REGIONAL RADAR. CONVECTION HAS JUST
RECENTLY FIRED OFF OVER SOUTHERN EMMONS COUNTY WITH ONE CLOUD TO
GROUND LIGHTNING STRIKE JUST SOUTH OF THE STATE LINE. STILL DO NOT
ANTICIPATE ANY SEVERE WEATHER THIS EVENING WITH 0-6KM BULK WIND
SHEAR LESS THAN 20KTS AND BOUNDARY LAYER MOISTURE VERY LIMITED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT TUE MAY 7 2013
INSTABILITY WILL CONTINUE TO INCREASE ACROSS EXTREME SOUTH
CENTRAL AND SOUTHEASTERN NORTH DAKOTA THIS AFTERNOON. AN AREA OF
CONVECTION ASSOCIATED WITH A STAGNANT UPPER LOW HAS ALREADY
DEVELOPED IN CENTRAL SOUTH DAKOTA THIS AFTERNOON. THIS ACTIVITY
SHOULD SERVE AS A MOISTURE SOURCE FOR POSSIBLE AFTERNOON
CONVECTION. THE FLY IN THE OINTMENT IS THAT SYNOPTIC SUBSIDENCE
NORTH OF THE UPPER LOW (USING Q-VECTOR DIVERGE AS A PROXY) SHOULD
KEEP ANY CONVECTIVE ACTIVITY SHALLOW. STILL THINK ENOUGH
MOISTURE/INSTABILITY WILL DEVELOP LATER THIS AFTERNOON TO WARRANT
AT LEAST A CHANCE FOR THUNDERSTORMS ACROSS
MCINTOSH...LAMOURE...AND DICKEY COUNTIES. THIS ACTIVITY SHOULD
STAY WELL BELOW SEVERE LIMITS.
PRECIP CHANCES ARE EXPECTED TO DIMINISH QUICKLY THIS EVENING WITH
THE LOSS OF DAYTIME HEATING. NORTHERN STREAM ENERGY MOVING ACROSS
HUDSON BAY WILL PUSH A COLD FRONT INTO NORTHERN NORTH DAKOTA AFTER
MIDNIGHT. HOWEVER...DRY CONDITIONS ARE EXPECTED AREAWIDE AFTER
MIDNIGHT SINCE MOISTURE CONVERGENCE ALONG THE BOUNDARY SHOULD BE
WEAK. THE INCREASING WINDS BEHIND THE FRONT SHOULD KEEP OVERNIGHT
LOWS ABOVE NORMAL NORTH (WILLISTON-MINOT). HOWEVER...FORECASTED A
FEW DEGREES BELOW THE COOLEST MOS GUIDANCE FOR OVERNIGHT LOWS
SOUTH AS WINDS SHOULD REMAIN CALM SOUTH OF HIGHWAY 200 THROUGH
SUNRISE.
THE COLD FRONT WILL THEN PUSH THROUGH THE REMAINDER OF WESTERN AND
CENTRAL NORTH DAKOTA WEDNESDAY. LINGERING MOISTURE AND INSTABILITY
SHOULD BE ENOUGH TO WARRANT A CHANCE FOR THUNDERSTORMS OVER
EXTREME SOUTH CENTRAL AND SOUTHEASTERN NORTH DAKOTA LATE WEDNESDAY
MORNING AND EARLY AFTERNOON. GIVEN THE CURRENT PROGS OF THE SPEED
OF THE FRONT...THE ATMOSPHERE SHOULD STABILIZE QUICKLY IN THE WAKE
OF THE BOUNDARY SOUTH AND SOUTHEAST LATE WEDNESDAY AFTERNOON.
WEDNESDAY HIGH TEMPERATURES SHOULD BE NEAR NORMAL...WITH READINGS
FROM THE 60S SOUTH TO THE UPPER 50S NORTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 PM CDT TUE MAY 7 2013
THE MAIN FOCUS FOR THE LONG TERM IS A POTENTIALLY STRONG COLD FRONT
BLASTING THROUGH THE REGION FRIDAY.
THE STAGNANT SPLIT FLOW AND DOMINANT RIDGE TO THE WEST WILL BEGIN TO
BREAK DOWN LATE THIS WEEK. THE STATIONARY UPPER LEVEL LOW IN SOUTH
DAKOTA WILL EJECT EASTWARD MAKING WAY FOR THE APPROACHING LONG WAVE
TROUGH AND ASSOCIATED COLD FRONT FRIDAY.
A WEAK FRONT WILL SWING THROUGH THE NORTHERN PLAINS WEDNESDAY
THROUGH THURSDAY. COLD DRY AIR ADVECTION BEHIND THE FRONT WILL
CONTINUE THROUGH EARLY FRIDAY. THIS SHOULD LIMIT THE AMOUNT OF
MOISTURE AND INSTABILITY AVAILABLE FOR THE FRIDAY SYSTEM. DUE TO THE
PROGRESSIVE NATURE OF THE SYSTEM AND LACK OF MOISTURE
AVAILABLE...PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT.
BOTH THE GFS AND EURO SHOW STEEP LAPSE RATES...STRONG 0-6KM SHEAR OF
45-55 KNOTS AND MODERATE FRONTOGENESIS. THIS WOULD NORMALLY FAVOR
STRONG THUNDERSTORMS. HOWEVER...DUE TO THE ABOVE MENTIONED LACK OF
MOISTURE ...ONLY SHOWERS WITH ISOLATED THUNDERSTORMS ARE EXPECTED.
THE 00Z EURO AND 12Z GFS SHOW SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING ALONG THE FRONT FRIDAY AFTERNOON AND QUICKLY EXITING
NORTH DAKOTA BY LATE FRIDAY EVENING. NORTHERLY WINDS WILL USHER IN
COLD AIR SATURDAY. DROPPING TEMPERATURES SATURDAY 10 TO 15 DEGREES
BELOW NORMAL.
SUNDAY AND MONDAY A HIGH AMPLITUDE RIDGE WILL PARK OVER EASTERN
MONTANA AND WESTERN NORTH DAKOTA. THIS RIDGE COMBINED WITH STRONG
WARM AIR ADVECTION WILL ALLOW TEMPERATURES TO RISE 10 TO 20 DEGREES
ABOVE NORMAL WITH READINGS IN THE 80S BY MONDAY OVER SOUTHWEST NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1237 AM CDT WED MAY 8 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW VFR CIGS/
VSBYS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. SCT/BKN MID CLOUDS
AT KJMS ASSOCIATED WITH AN UPPER LEVEL LOW IN SOUTH DAKOTA...AND
CLOUDS INCREASING ALONG THE NORTHERN BORDER BEHIND AN ADVANCING
COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH THE AERODROMES
THROUGH 15Z WEDNESDAY WITH A WIND SHIFT TO THE NORTHEAST. EXPECT
WINDS WEDNESDAY TO RANGE BETWEEN 15KT AND 20KT. EXPECTING DRY
CONDITIONS WITH THIS FRONT AT LEAST THROUGH 06Z THURSDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TM
LONG TERM...AJ
AVIATION...KS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
333 PM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LEVEL LOW WILL DRIFT TO THE NORTHEAST...REACHING
SOUTHERN NEW YORK BY THURSDAY. WEAK HIGH PRESSURE WILL BUILD
EAST OVER THE COMMONWEALTH THURSDAY AFTERNOON INTO EARLY FRIDAY.
MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY
AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT
WILL BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A SPRAWLING UPPER LOW NEAR STAUNTON VA AROUND MID DAY...WILL
CONTINUE TO MOVE NORTHEAST TODAY...KEEPING THE WEATHER CONDITIONS
UNSETTLED AND EVEN A LITTLE HUMID.
THE AXIS OF ANOMALOUS EASTERLY LOW LEVEL FLOW AND HIGH PWAT AIR
WILL LIFT INTO NORTHERN PA AND SOUTHERN NY AS THE DAY PROGRESSES.
FOR THE NEXT FEW HOURS HOWEVER...THE BEST MOISTURE AND FORCING
WILL CONTINUE TO BE ASSOCIATED WITH THE CLUSTER OF SHOWERS AND
STORMS MOVING WNW THROUGH THE MIDDLE AND UPPER SUSQ VALLEY TWD
THE NORTHERN MOUNTAINS...A BIT SOUTH OF WHERE THE RUC13 HAS ITS
AXIS OF QPF FOR THE NEXT 6 HRS OR SO. HRRR IS SIMILARLY TOO FAR
NORTH WITH THE MCS...WHILE THE HIGH-RES ARW DOESN`T SHOW ANY
ORGANIZED CONVECTION AT ALL.
RADAR ESTIMATES THAT AS MUCH AS AN INCH AN HOUR WAS FALLING UNDER
SOME OF THE STRONGER CORES. SEVERE STORMS DO NOT LOOK TO BE A BIG
THREAT...MAIN CONCERN WILL BE FOR LOCALLY HEAVY DOWNPOURS.
ELSEWHERE OVER ABOUT THE SRN HALF OF THE FCST AREA...SOMEWHAT
DRIER AIR AT MID LEVELS IS HELPING DEVELOP BREAKS IN THE CLOUDS
WHICH ARE HELPING DESTABILIZE THE ATMOSPHERE...WITH LATEST RAP
SHOWING CAPES IN THE 500-1000J RANGE. MID LEVEL LAPSE RATES ARE
MARGINALLY STEEP GIVEN THE COLD AIR ALOFT ACCOMPANYING THE UPPER
LOW...SO WE WILL STAY VULNERABLE TO ADDITIONAL CONVECTION FIRING
UNDER THE STRONG MAY SUNSHINE.
ENS MEAN AND OPER QPF INDICATES MAINLY LIGHT QPF AS AN AVERAGE
ACROSS THE AREA...A QUARTER INCH OR LESS...BUT OBVIOUSLY THE
CONVECTIVE CLUSTER WILL SEE LOCALLY HIGHER AMOUNTS...WITH A HALF
INCH OR MORE LIKLEY OVER MUCH OF MY NRN FCST AREA.
HIGH TEMPS THIS AFTERNOON WILL VARY FROM THE LOWER 60S ACROSS
THE LAURELS AND NW MTNS...TO THE MID AND UPPER 60S ELSEWHERE.
PRECIP WILL BECOME MORE SCATTERED TONIGHT AFTER WE LOSE OUR
HEATING. THE BEST CHANCES FOR RAIN LOOK LIKE THEY WILL BE OVER
THE FAR EAST AND WEST AS THE UPPER LOW MOVES UP AND THROUGH THE
REGION. AM MORE CONFIDENT ABOUT WESTERN RAINS AS THIS LOOKS LIKE
A GOOD PLACE FOR A DEFORMATION ZONE TO FORM AS THE LOW TRAVERSES
THE AREA.
TONIGHT`S LOWS WITHIN A COUPLE OF DEGREES EITHER SIDE OF 50 WILL
AVERAGE A BIT ABOVE NORMAL.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THE UPPER LOW WILL BE MOVING INTO NY AND SRN NEW ENGLAND AS THE
DAY PROGRESSES THURSDAY. THEORETICALLY WE WILL BE SEEING RISING
UPPER HEIGHTS AND EVEN SOME INCREASE IN RIDGING ALOFT APPROACHING
FROM THE WEST...BUT SHORT RANGE GUIDANCE IS HINTING AT CONTINUED
INSTABILITY SHOWERS...ESPECIALLY AS THE DAY WARMS UP. ALSO THERE
IS THE HINT OF PERHAPS SOME LOCALLY MORE ORGANIZED RAINS DEVELOPING
OVER NWRN AREAS AS A DEFORMATION ZONE POSSIBLY TRIES TO ORGANIZE
IN THE NW QUADRANT OF THE UPPER LOW. THAT IS JUST A PATTERN
RECOGNITION THING AT THIS RANGE...WITH ONLY THE OPERATIONAL NAM
SUGGESTING ANYTHING MORE THAN SCATTERED SHOWERS THROUGH 18Z.
WITH A MIX OF SUN AND CLOUDS WE SHOULD EASILY WARM INTO THE 60S
TO LOWER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
LEFT THU NIGHT MAINL DRY...AS WEAK RIDGING PREVAILS.
DID UP TEMPS ON FRIDAY...GIVEN SW FLOW. IN SLIGHT RISK
FOR STRONG TO SEVERE STORMS...SOMETHING TO WATCH...GIVEN
FCST MAX TEMPS.
NOT A LOT OF CHANGE FOR FRIDAY NIGHT INTO SAT NIGHT.
SERIES OF COLD FRONTS MOVE ACROSS. ONE FRONT EARLY
SAT...THEN ANOTHER SATURDAY NIGHT. THE REAL COLD AIR
WILL COME IN LATER SUNDAY...BEHIND THE UPPER LVL FRONT.
NEAR RECORD COLD LIKELY FROM LATE SUNDAY INTO TUE AM.
FROST AND FREEZE ISSUES WILL BE LIKELY.
AS THE HIGH MOVES TO TH SE LATE TUE...MODELS SHOW A
STRONG WESTERLY FLOW OF VERY WARM AIR FOR WED INTO THU...
BEFORE ANOTHER COLD SPELL LATER IN THE WEEK. PATERN
SUPPORT STRONG TO SEVERE STORMS POSSIBLE WITH WARM
FRONT...DID PUT LOW POPS IN ALONG THE NY BORDER.
DID NOT GO TO CRAZY WITH MAX TEMPS AT THIS POINT...
BUT COULD SEE SOME MID 80S.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
A LOW PRESSURE SYSTEM CURRENTLY OVER WEST VIRGINIA WILL CONTINUE
TO SLOWLY SPIN NORTH TODAY. AS THE SYSTEM PULLS ATLANTIC MOISTURE
THROUGH PENNSYLVANIA... WIDESPREAD SHOWERS AND ISOLATED
THUNDERSTORMS WILL CONTINUE FROM KIPT TO KBFD THROUGHOUT THE
AFTERNOON HOURS. OTHER TERMINALS WILL SEE SCATTERED SHOWERS AND
A RUMBLE OR TWO OF THUNDER.
SHOWERS WILL DECREASE OVERNIGHT AS THE LOW MOVES NORTH BUT THE
LIKELIHOOD OF FOG INCREASES AFTER 06Z. EXPECT MVFR/IFR...WITH SOME
SITES POTENTIALLY REACHING LIFR... VSBYS THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THURSDAY
AFTERNOON INTO EARLY FRIDAY...BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
THU...WIDESPREAD MVFR/IFR IN MORNING FOG. THEN MAINLY VFR
CONDITIONS WITH MVFR SCATTERED SHOWERS AND ISOLATED TSTMS.
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/MARTIN
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE/COLBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
151 PM EDT WED MAY 8 2013
.SYNOPSIS...
AN UPPER LEVEL LOW WILL DRIFT TO THE NORTHEAST...REACHING
SOUTHERN NEW YORK BY THURSDAY. WEAK HIGH PRESSURE WILL BUILD EAST
OVER THE COMMONWEALTH THURSDAY AFTERNOON INTO EARLY FRIDAY.
MILDER...AND MORE HUMID AIR WILL PUSH INTO THE REGION FRIDAY
AFTERNOON THROUGH SATURDAY...AHEAD OF A STRONG COLD FRONT THAT
WILL BRING UNSEASONABLY COOL AIR TO THE REGION LATER IN THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
A SPRAWLING UPPER LOW NEAR STAUNTON VA AROUND MID DAY...WILL
CONTINUE TO MOVE NORTHEAST TODAY...KEEPING THE WEATHER CONDITIONS
UNSETTLED AND EVEN A LITTLE HUMID.
THE AXIS OF ANOMALOUS EASTERLY LOW LEVEL FLOW AND HIGH PWAT AIR
WILL LIFT INTO NORTHERN PA AND SOUTHERN NY AS THE DAY PROGRESSES.
FOR THE NEXT FEW HOURS HOWEVER...THE BEST MOISTURE AND FORCING
WILL CONTINUE TO BE ASSOCIATED WITH THE CLUSTER OF SHOWERS AND
STORMS MOVING WNW THROUGH THE MIDDLE AND UPPER SUSQ VALLEY TWD THE
NORTHERN MOUNTAINS...A BIT SOUTH OF WHERE THE RUC13 HAS ITS AXIS
OF QPF FOR THE NEXT 6 HRS OR SO. HRRR IS SIMILARLY TOO FAR NORTH
WITH THE MCS...WHILE THE HIGH-RES ARW DOESN`T SHOW ANY ORGANIZED
CONVECTION AT ALL.
RADAR ESTIMATES THAT AS MUCH AS AN INCH AN HOUR WAS FALLING UNDER
SOME OF THE STRONGER CORES. SEVERE STORMS DO NOT LOOK TO BE A BIG
THREAT...MAIN CONCERN WILL BE FOR LOCALLY HEAVY DOWNPOURS.
ELSEWHERE OVER ABOUT THE SRN HALF OF THE FCST AREA...SOMEWHAT
DRIER AIR AT MID LEVELS IS HELPING DEVELOP BREAKS IN THE CLOUDS
WHICH ARE HELPING DESTABILIZE THE ATMOSPHERE...WITH LATEST RAP
SHOWING CAPES IN THE 500-1000J RANGE. MID LEVEL LAPSE RATES ARE
MARGINALLY STEEP GIVEN THE COLD AIR ALOFT ACCOMPANYING THE UPPER
LOW...SO WE WILL STAY VULNERABLE TO ADDITIONAL CONVECTION FIRING
UNDER THE STRONG MAY SUNSHINE.
ENS MEAN AND OPER QPF INDICATES MAINLY LIGHT QPF AS AN AVERAGE
ACROSS THE AREA...A QUARTER INCH OR LESS...BUT OBVIOUSLY THE
CONVECTIVE CLUSTER WILL SEE LOCALLY HIGHER AMOUNTS...WITH A HALF
INCH OR MORE LIKLEY OVER MUCH OF MY NRN FCST AREA.
HIGH TEMPS THIS AFTERNOON WILL VARY FROM THE LOWER 60S ACROSS THE
LAURELS AND NW MTNS...TO THE MID AND UPPER 60S ELSEWHERE.
PRECIP WILL BECOME MORE SCATTERED TONIGHT AFTER WE LOSE OUR
HEATING. THE BEST CHANCES FOR RAIN LOOK LIKE THEY WILL BE OVER THE
FAR EAST AND WEST AS THE UPPER LOW MOVES UP AND THROUGH THE
REGION. AM MORE CONFIDENT ABOUT WESTERN RAINS AS THIS LOOKS LIKE A
GOOD PLACE FOR A DEFORMATION ZONE TO FORM AS THE LOW TRAVERSES
THE AREA.
TONIGHT`S LOWS WITHIN A COUPLE OF DEGREES EITHER SIDE OF 50 WILL
AVERAGE A BIT ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY/...
THE UPPER LOW WILL BE MOVING INTO NY AND SRN NEW ENGLAND AS THE
DAY PROGRESSES THURSDAY. THEORETICALLY WE WILL BE SEEING RISING
UPPER HEIGHTS AND EVEN SOME INCREASE IN RIDGING ALOFT APPROACHING
FROM THE WEST...BUT SHORT RANGE GUIDANCE IS HINTING AT CONTINUED
INSTABILITY SHOWERS...ESPECIALLY AS THE DAY WARMS UP. ALSO THERE
IS THE HINT OF PERHAPS SOME LOCALLY MORE ORGANIZED RAINS DEVELOPING
OVER NWRN AREAS AS A DEFORMATION ZONE POSSIBLY TRIES TO ORGANIZE
IN THE NW QUADRANT OF THE UPPER LOW. THAT IS JUST A PATTERN
RECOGNITION THING AT THIS RANGE...WITH ONLY THE OPERATIONAL NAM
SUGGESTING ANYTHING MORE THAN SCATTERED SHOWERS THROUGH 18Z.
WITH A MIX OF SUN AND CLOUDS WE SHOULD EASILY WARM INTO THE 60S TO
LOWER 70S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
MINOR CHANGES MADE FOR THE MOST PART.
THE UPPER LVL LOW WILL HAVE TO TRACK TO THE NORTH OF EAST...BEFORE
MOVING AWAY FROM THE AREA LATE IN THE WEEK.
MOST OF THU NIGHT AND FRIDAY DOES NOT LOOK BAD. IT COULD BE ON
THE WARM SIDE FRIDAY...AS NEXT COLD FRONT DROPS SLOWLY SE AND
WEAKENS. DID EDGE POPS UP SOME.
A MUCH STRONGER COLD FRONT MOVES INTO THE AREA LATE SATURDAY AND
EARLY SUNDAY...FOLLOWED BY A SECONDARY FRONT. EXPECT SHOWERS
ASSOCIATED WITH THE CFRONT TO BE EAST OF THE AREA BY SUNDAY AFT.
HOWEVER...THE MUCH COLDER AIR /-2 TO -3 SIGMA AT 850 MB ACROSS WRN
PENN BY 12Z MONDAY/ PLOWING INTO THE REGION FOR LATER SUNDAY INTO
EARLY NEXT WEEK...WILL PICK UP MOISTURE FROM THE GLAKES AND LIFT IT
ACROSS THE ALLEGHENIES. THIS WILL MAINTAIN PLENTY OF CLOUDS AND
SCATTERED RAIN SHOWERS FOR THE NRN AND WRN MTNS OF PA. 925 MB TEMPS
OF -1 TO -3C...AND 850 MB TEMPS OF -5 OT -7C WILL BE COLD ENOUGH TO
SUPPORT AT LEAST A MIX OF WET SNOW WITH ANY OF THE SHOWERS ACROSS
THE HIGHER TERRAIN /AOA 1500 FT MSL/.
FROST...FREEZE FLAGS MAY BE NEEDED FOR SUNDAY NIGHT AND MONDAY NIGHT
FOR WHAT LOOKS BE NEAR RECORD...OR RECORD COLD.
BY MID TO LATE WEEK...IT COULD BE ON THE WARM SIDE...WITH
TEMPS IN THE 70S IF NOT 80S...AS THE HIGH MOVES SE...AND WINDS
SHIFT TO THE SW.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
A LOW PRESSURE SYSTEM CURRENTLY OVER WEST VIRGINIA WILL CONTINUE
TO SLOWLY SPIN NORTH TODAY. AS THE SYSTEM PULLS ATLANTIC MOISTURE
THROUGH PENNSYLVANIA... WIDESPREAD SHOWERS AND ISOLATED
THUNDERSTORMS WILL CONTINUE FROM KIPT TO KBFD THROUGHOUT THE
AFTERNOON HOURS. OTHER TERMINALS WILL SEE SCATTERED SHOWERS AND A
RUMBLE OR TWO OF THUNDER.
SHOWERS WILL DECREASE OVERNIGHT AS THE LOW MOVES NORTH BUT THE
LIKELIHOOD OF FOG INCREASES AFTER 06Z. EXPECT MVFR/IFR...WITH SOME
SITES POTENTIALLY REACHING LIFR... VSBYS THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD EAST OVER THE COMMONWEALTH THURSDAY
AFTERNOON INTO EARLY FRIDAY...BRINGING MOSTLY VFR FLYING
CONDITIONS.
.OUTLOOK...
THU...WIDESPREAD MVFR/IFR IN MORNING FOG. THEN MAINLY VFR
CONDITIONS WITH MVFR SCATTERED SHOWERS AND ISOLATED TSTMS.
FRI...COLD FRONT MOVES THROUGH. SCT SHOWERS AND PERHAPS A
THUNDERSTORM LATE ACCOMPANIED BY LOCAL MVFR CONDITIONS.
SAT...MORE SHOWERS POSSIBLE WITH ANOTHER COLD FRONT.
SUN...SHOWERS EARLY...THEN IMPROVING CONDITIONS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/MARTIN
AVIATION...LA CORTE/COLBERT
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
803 PM CDT THU MAY 9 2013
.UPDATE...
SEVERE WEATHER THREAT HAS DIMINISHED WITH THE MAIN MCS MOVING
EAST AND SOUTHEAST OUT OF THE CWA. THE AIRMASS IN ITS WAKE HAS
BEEN WORKED OVER...AS EVIDENCED BY 7PM SURFACE TEMPERATURES ON THE
COOL SIDE WITH DEWPOINTS A FEW DEGREES LOWER THAN EARLIER TODAY.
THIS INCREASED STABILITY PRESUMABLY COMBINED WITH SUBSIDENCE ON
THE NORTHWEST SIDE OF THE DEPARTING MCS HAS SQUASHED CONVECTION
THAT ORIGINATED WEST OF THE CWA AS IT MOVED CLOSER TO OUR AREA.
FOR TONIGHT A WEAK COLD FRONT WILL SLIP THROUGH THE AREA.
ALTHOUGH THE SURFACE REFLECTION OF THE FRONT WILL NOT BE WELL
DEFINED...THE 850MB FRONT WILL HAVE MORE DEFINITION AND WOULD BE A
FAVORED FEATURE FOR NEW CONVECTIVE DEVELOPMENT OVERNIGHT. THE 00Z
FWD SOUNDING INDICATES MARGINAL AMOUNTS OF MOISTURE/INSTABILITY
ARE AVAILABLE ALOFT...AND SHOULD ADDITIONAL FORCING VIA VORTICITY
MAXIMA EITHER EMBEDDED WITHIN THE SYNOPTIC FLOW OR GENERATED BY
ONGOING CONVECTION IN THE TX PANHANDLE ACCOMPANY THE FROPA...
ADDITIONAL SCATTERED ELEVATED NON-SEVERE CONVECTION WOULD RESULT.
WILL KEEP 30 POPS BROAD-BRUSHED ACROSS THE AREA TONIGHT.
FOR FRIDAY THE SHORT-TERM GUIDANCE IS INDICATING THAT THE 850MB
FRONT WILL STALL JUST NORTH OF THE I-10 CORRIDOR. THE 850MB FRONT
IS OFTEN A FAVORED LOCATION FOR MCS/S TO TRACK ALONG...AND MOST
OF THE GUIDANCE IS SUGGESTING A MCS WILL AFFECT THAT AREA
TOMORROW. THE FAVORED MCS TRACK LOCATION MAY BE TOO FAR SOUTH TO
IMPACT OUR CWA...AND HAVE LOWERED POPS TO 60 PERCENT ACROSS THE
SOUTHERN ZONES TO REFLECT MORE UNCERTAINTY IN THE CONVECTIVE
FORECAST. ACROSS THE REST OF NORTH TEXAS...AN UNSTABLE AIRMASS
SHOULD DEVELOP WITH HEATING...BUT WEAK COLD/DRY ADVECTION BEHIND
THE FRONT IS INDICATIVE OF SUBSIDENCE. IN SUCH AN ENVIRONMENT
CONVECTION SHOULD REMAIN ISOLATED TO SCATTERED...AND WOULD
LIKELY STRUGGLE TO ORGANIZE INTO MEANINGFUL CLUSTERS. BUT DEPENDING
ON THE AMOUNT OF INSTABILITY...A SEVERE THREAT IS POSSIBLE WITH
THE STRONGER CORES.
TR.92
&&
.AVIATION...
PRECIP THAT WAS APPROACHING METROPLEX FROM WEST HAS WEAKENED.
KDYX RADAR SHOWS LARGE AREA OF RETURNS NEAR JACK COUNTY BUT THAT
IS A/P...NOT THUNDERSTORMS. HAVE REMOVED ALL TS MENTION FROM THE
TAFS AS SHORT WAVE HAS PASSED THROUGH THE AREA (MCV APPARENT NEAR
TYLER ON RADAR). GUIDANCE SHIFTS FOCUS FOR TOMORROW TO WACO AREA
AND SOUTH...BUT HI RES MODELS AND RUC SHOW THE 850MB FRONT
ALREADY SOUTH OF WACO AND FEEL THAT THE THUNDER THREAT WILL BE
SOUTH OF THE TAF SITE. MVFR STRATUS HAS ALREADY RETURNED TO
WACO...AND EXPECT IT BACK INTO THE METROPLEX LATER THIS EVENING.
84
&&
.PREV DISCUSSION... /ISSUED 339 PM CDT THU MAY 9 2013/
LARGE AREA OF RAIN AND THUNDERSTORMS CONTINUES TO AFFECT MAINLY
THE EASTERN TWO-THIRDS OF THE CWA WITH THE STRONGEST/SEVERE STORMS
CURRENTLY LOCATED IN THE SOUTHERN COUNTIES...MOVING EAST. THESE
SEVERE STORMS ARE PRODUCING LARGE HAIL UP TO THE SIZE OF GOLF BALLS
AND DAMAGING WINDS UP TO 75 MPH. ADDITIONAL STORMS ARE ALSO
DEVELOPING TO OUR WEST ALONG THE DRYLINE FROM SWEETWATER TOWARDS
SAN ANGELO. EARLIER HI-RESOLUTION MODEL RUNS SUGGESTED THE STORMS
ALONG THE DRYLINE WOULD EVOLVE INTO AN MCS/SQUALL LINE THAT MOVES
ACROSS THE REGION LATE THIS AFTERNOON AND THIS EVENING.
HOWEVER...MOST OF THE LATEST RUNS OF THESE MODELS DO NOT SUGGEST
THESE STORMS WILL MERGE INTO A COMPLEX...BUT INSTEAD WILL
DISSIPATE AROUND SUNSET. ONE REASON FOR THIS COULD BE THAT THE
LEAD SHORTWAVE THAT IS GENERATING BOTH AREAS OF THUNDERSTORMS WILL
BE EJECTING OUT OF THE REGION THIS EVENING. BASED ON THESE LATEST
TRENDS AND THINKING...THINK THAT THE STORMS ACROSS THE SOUTHERN
COUNTIES WILL CONTINUE TO BE THE MAIN FOCUS THIS AFTERNOON AND
EVENING AS THEY MOVE EAST INTO OUR SOUTHEASTERN COUNTIES. A THREAT
FOR SEVERE WEATHER WILL STILL EXIST WITH THESE STORMS/COMPLEX BUT
THE THREAT WILL BE DIMINISHING CLOSE TO SUNSET. WHILE WE CANNOT
IGNORE THE STORMS TO OUR WEST...IT APPEARS LESS LIKELY THAT THESE
STORMS WILL AFFECT A SIGNIFICANT PORTION OF OUR CWA BUT WE WILL BE
WATCHING THEIR OVERALL EVOLUTION OVER THE NEXT FEW HOURS. AT THIS
TIME DO NOT SEE A NEED TO MAKE ADJUSTMENTS TO THE CURRENT SEVERE
THUNDERSTORM WATCH BOX UNTIL WE GET A BETTER FEEL AND HANDLE ON
THE STORMS TO THE WEST.
A COLD FRONT THAT IS CURRENTLY LOCATED ACROSS WESTERN OKLAHOMA AND
THE TEXAS PANHANDLE WILL CONTINUE TO SLOWLY MOVE SOUTH OVERNIGHT
AND MOVE ACROSS NORTH AND CENTRAL TEXAS ON FRIDAY. ORGANIZED
CONVECTION ALONG THE FRONT IS NOT EXPECTED AT THIS TIME...BUT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL LIKELY
CONTINUE AHEAD OF THE FRONT TONIGHT AND FRIDAY MORNING. ANOTHER
STRONG SHORTWAVE WILL EJECT ACROSS THE STATE TOMORROW AND IT LOOKS
LIKE ANOTHER COMPLEX OF STORMS WILL DEVELOP IN THE CONCHO
VALLEY/CENTRAL TEXAS AND MOVE EAST. THUS...HAVE INCREASED POPS
ACROSS THE SOUTHERN COUNTIES FOR TOMORROW. SEVERE WEATHER WITH A
MAIN THREAT FOR HAIL AND DAMAGING WINDS WILL AGAIN BE POSSIBLE
WITH THIS MCS.
THE ACTIVE WEATHER PATTERN SHOULD BEGIN TO SETTLE DOWN FRIDAY
NIGHT AS THE SURFACE FRONT COMPLETELY CLEARS THE CWA AND MAIN
UPPER LEVEL TROUGHING OVER THE REGION BEGINS TO SHIFT EAST.
HOWEVER...THE 850 AND 700 MB FRONTS WILL STILL BE MOVING ACROSS
THE SOUTHERN COUNTIES SO WILL CONTINUE TO LINGER POPS MAINLY SOUTH
OF INTERSTATE 20 FRIDAY NIGHT AND SATURDAY. THE FORECAST LOOKS DRY
BEYOND SATURDAY UNTIL NEXT TUESDAY.
ANOTHER PIECE OF ENERGY IS EXPECTED TO BREAK OFF OF THE MAIN UPPER
LEVEL TROUGH AND STALL OVER NORTHERN MEXICO THIS WEEKEND AND EARLY
NEXT WEEK. THIS UPPER LEVEL LOW WILL THEN EJECT NORTHEAST INTO THE
TEXAS PANHANDLE ON TUESDAY. THERES A CHANCE THAT ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR TUESDAY THROUGH
THURSDAY AS THIS LOW SLOWLY MOVES EAST ACROSS THE PLAINS. THE
ECMWF AND GFS ARE IN PRETTY GOOD AGREEMENT THAT THE UPPER LOW WILL
ENTER THE SOUTHERN PLAINS ON TUESDAY BUT THE GFS IS FASTER TO MOVE
THE LOW EAST OF THE REGION. IT IS TOO EARLY TO ASSESS THE SEVERE
POTENTIAL AT THIS TIME...BUT MOISTURE LOOKS AMPLE FOR THE
DEVELOPMENT OF STORMS DURING THIS TIME FRAME AND FORECAST
SOUNDINGS SUGGEST SOME DECENT INSTABILITY AND A WEAK CAP IS
POSSIBLE DURING THIS PERIOD.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 63 78 59 79 57 / 30 30 20 10 5
WACO, TX 65 76 61 78 55 / 30 60 40 10 10
PARIS, TX 61 77 57 76 53 / 30 30 20 10 5
DENTON, TX 60 78 57 79 53 / 30 30 20 10 5
MCKINNEY, TX 60 78 57 78 52 / 30 30 20 10 5
DALLAS, TX 64 79 60 79 57 / 30 30 20 10 5
TERRELL, TX 63 78 58 78 55 / 30 30 20 10 5
CORSICANA, TX 65 77 61 78 56 / 30 50 40 10 10
TEMPLE, TX 66 76 62 77 55 / 30 60 40 20 10
MINERAL WELLS, TX 61 77 57 78 52 / 30 30 20 10 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
635 PM CDT THU MAY 9 2013
.AVIATION...
PRECIP THAT WAS APPROACHING METROPLEX FROM WEST HAS WEAKENED.
KDYX RADAR SHOWS LARGE AREA OF RETURNS NEAR JACK COUNTY BUT THAT
IS A/P...NOT THUNDERSTORMS. HAVE REMOVED ALL TS MENTION FROM THE
TAFS AS SHORT WAVE HAS PASSED THROUGH THE AREA (MCV APPARENT NEAR
TYLER ON RADAR). GUIDANCE SHIFTS FOCUS FOR TOMORROW TO WACO AREA
AND SOUTH...BUT HI RES MODELS AND RUC SHOW THE 850MB FRONT
ALREADY SOUTH OF WACO AND FEEL THAT THE THUNDER THREAT WILL BE
SOUTH OF THE TAF SITE. MVFR STRATUS HAS ALREADY RETURNED TO
WACO...AND EXPECT IT BACK INTO THE METROPLEX LATER THIS EVENING.
84
&&
.PREV DISCUSSION... /ISSUED 339 PM CDT THU MAY 9 2013/
LARGE AREA OF RAIN AND THUNDERSTORMS CONTINUES TO AFFECT MAINLY
THE EASTERN TWO-THIRDS OF THE CWA WITH THE STRONGEST/SEVERE STORMS
CURRENTLY LOCATED IN THE SOUTHERN COUNTIES...MOVING EAST. THESE
SEVERE STORMS ARE PRODUCING LARGE HAIL UP TO THE SIZE OF GOLF BALLS
AND DAMAGING WINDS UP TO 75 MPH. ADDITIONAL STORMS ARE ALSO
DEVELOPING TO OUR WEST ALONG THE DRYLINE FROM SWEETWATER TOWARDS
SAN ANGELO. EARLIER HI-RESOLUTION MODEL RUNS SUGGESTED THE STORMS
ALONG THE DRYLINE WOULD EVOLVE INTO AN MCS/SQUALL LINE THAT MOVES
ACROSS THE REGION LATE THIS AFTERNOON AND THIS EVENING.
HOWEVER...MOST OF THE LATEST RUNS OF THESE MODELS DO NOT SUGGEST
THESE STORMS WILL MERGE INTO A COMPLEX...BUT INSTEAD WILL
DISSIPATE AROUND SUNSET. ONE REASON FOR THIS COULD BE THAT THE
LEAD SHORTWAVE THAT IS GENERATING BOTH AREAS OF THUNDERSTORMS WILL
BE EJECTING OUT OF THE REGION THIS EVENING. BASED ON THESE LATEST
TRENDS AND THINKING...THINK THAT THE STORMS ACROSS THE SOUTHERN
COUNTIES WILL CONTINUE TO BE THE MAIN FOCUS THIS AFTERNOON AND
EVENING AS THEY MOVE EAST INTO OUR SOUTHEASTERN COUNTIES. A THREAT
FOR SEVERE WEATHER WILL STILL EXIST WITH THESE STORMS/COMPLEX BUT
THE THREAT WILL BE DIMINISHING CLOSE TO SUNSET. WHILE WE CANNOT
IGNORE THE STORMS TO OUR WEST...IT APPEARS LESS LIKELY THAT THESE
STORMS WILL AFFECT A SIGNIFICANT PORTION OF OUR CWA BUT WE WILL BE
WATCHING THEIR OVERALL EVOLUTION OVER THE NEXT FEW HOURS. AT THIS
TIME DO NOT SEE A NEED TO MAKE ADJUSTMENTS TO THE CURRENT SEVERE
THUNDERSTORM WATCH BOX UNTIL WE GET A BETTER FEEL AND HANDLE ON
THE STORMS TO THE WEST.
A COLD FRONT THAT IS CURRENTLY LOCATED ACROSS WESTERN OKLAHOMA AND
THE TEXAS PANHANDLE WILL CONTINUE TO SLOWLY MOVE SOUTH OVERNIGHT
AND MOVE ACROSS NORTH AND CENTRAL TEXAS ON FRIDAY. ORGANIZED
CONVECTION ALONG THE FRONT IS NOT EXPECTED AT THIS TIME...BUT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL LIKELY
CONTINUE AHEAD OF THE FRONT TONIGHT AND FRIDAY MORNING. ANOTHER
STRONG SHORTWAVE WILL EJECT ACROSS THE STATE TOMORROW AND IT LOOKS
LIKE ANOTHER COMPLEX OF STORMS WILL DEVELOP IN THE CONCHO
VALLEY/CENTRAL TEXAS AND MOVE EAST. THUS...HAVE INCREASED POPS
ACROSS THE SOUTHERN COUNTIES FOR TOMORROW. SEVERE WEATHER WITH A
MAIN THREAT FOR HAIL AND DAMAGING WINDS WILL AGAIN BE POSSIBLE
WITH THIS MCS.
THE ACTIVE WEATHER PATTERN SHOULD BEGIN TO SETTLE DOWN FRIDAY
NIGHT AS THE SURFACE FRONT COMPLETELY CLEARS THE CWA AND MAIN
UPPER LEVEL TROUGHING OVER THE REGION BEGINS TO SHIFT EAST.
HOWEVER...THE 850 AND 700 MB FRONTS WILL STILL BE MOVING ACROSS
THE SOUTHERN COUNTIES SO WILL CONTINUE TO LINGER POPS MAINLY SOUTH
OF INTERSTATE 20 FRIDAY NIGHT AND SATURDAY. THE FORECAST LOOKS DRY
BEYOND SATURDAY UNTIL NEXT TUESDAY.
ANOTHER PIECE OF ENERGY IS EXPECTED TO BREAK OFF OF THE MAIN UPPER
LEVEL TROUGH AND STALL OVER NORTHERN MEXICO THIS WEEKEND AND EARLY
NEXT WEEK. THIS UPPER LEVEL LOW WILL THEN EJECT NORTHEAST INTO THE
TEXAS PANHANDLE ON TUESDAY. THERES A CHANCE THAT ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR TUESDAY THROUGH
THURSDAY AS THIS LOW SLOWLY MOVES EAST ACROSS THE PLAINS. THE
ECMWF AND GFS ARE IN PRETTY GOOD AGREEMENT THAT THE UPPER LOW WILL
ENTER THE SOUTHERN PLAINS ON TUESDAY BUT THE GFS IS FASTER TO MOVE
THE LOW EAST OF THE REGION. IT IS TOO EARLY TO ASSESS THE SEVERE
POTENTIAL AT THIS TIME...BUT MOISTURE LOOKS AMPLE FOR THE
DEVELOPMENT OF STORMS DURING THIS TIME FRAME AND FORECAST
SOUNDINGS SUGGEST SOME DECENT INSTABILITY AND A WEAK CAP IS
POSSIBLE DURING THIS PERIOD.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 63 75 59 79 57 / 30 40 20 10 5
WACO, TX 65 75 61 78 55 / 50 80 40 10 10
PARIS, TX 61 75 57 76 53 / 30 30 20 10 5
DENTON, TX 60 74 57 79 53 / 30 30 20 10 5
MCKINNEY, TX 60 75 57 78 52 / 30 30 20 10 5
DALLAS, TX 64 76 60 79 57 / 30 40 20 10 5
TERRELL, TX 63 75 58 78 55 / 40 50 20 10 5
CORSICANA, TX 65 74 61 78 56 / 50 70 40 10 10
TEMPLE, TX 66 75 62 77 55 / 50 80 40 20 10
MINERAL WELLS, TX 61 74 57 78 52 / 40 50 20 10 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
113 PM CDT WED MAY 8 2013
.AVIATION...
FOR THE 18Z TAFS...TIMING THE ONSET OF MVFR STRATUS TONIGHT AND
THEN THUNDERSTORM CHANCES OVER THE NEXT 24 TO 30 HRS ARE THE
PRIMARY FORECAST CONCERNS.
STRATUS...ASIDE FROM THE STRATUS THAT WAS WITHIN 5 MILES OF KACT
AT THE TIME OF THIS DISCUSSION...STRATUS IS EXPECTED TO SURGE
NORTH THROUGH ALL AREA TAF SITES AFTER MIDNIGHT TONIGHT. FOR THE
KACT STRATUS...THE EASTERN EDGE OF THE STRATUS DECK WAS SHOWING
SIGNS OF ERODING AT THE TIME OF THIS DISCUSSION...SO DESPITE ITS
VERY CLOSE PROXIMITY TO THE AIRPORT WILL NOT CARRY A CIG TO START
OFF THE TAFS THERE. OTHERWISE...MOST GUIDANCE INDICATES A RETURN
OF STRATUS AFTER MIDNIGHT TONIGHT...WITH MVFR STRATUS MOVING OVER
KACT BY 07Z AND THEN OVER THE METROPLEX AREA TAF SITES BY 09Z.
MVFR STRATUS WILL LIKELY HOLD UNTIL 17Z WHEN DAYTIME HEATING WILL
HELP LIFT CIGS TO VFR LEVELS.
THUNDERSTORM CHANCES...STORMS ARE LIKELY TO DEVELOP ALONG THE
DRYLINE FROM WESTERN OK SOUTH THRU THE SOUTHERN TX PANHANDLE THIS
AFTERNOON. THESE STORMS WILL LIKELY MOVE NORTHEAST THROUGH THIS
EVENING AND MAY GROW UPSCALE INTO A LINE WHILE CONTINUING EAST
TOWARDS NORTH TX. AT THIS TIME CONFIDENCE IS FAIRLY HIGH THAT THIS
EVENING AND OVERNIGHT THUNDERSTORM ACTIVITY WILL REMAIN TOO FAR
NORTH OF DFW AREA TAF SITES TO HAVE ANY DIRECT IMPACT ON
OPERATIONS.
THE DRYLINE IS EXPECTED TO MOVE MUCH FURTHER EAST BY THURSDAY
AFTERNOON WHICH MAY CAUSE THUNDERSTORMS TO DEVELOP JUST TO THE
WEST OF THE DFW AREA TAF SITES DURING THE PEAK HEATING HRS OF THE
DAY. FOR NOW WENT AHEAD WITH A MENTION OF VCTS IN THE EXTENDED
PORTION OF THE DFW AREA TAF TO ACCOUNT FOR THIS POSSIBILITY.
GUIDANCE INDICATES THAT THUNDERSTORMS COULD DEVELOP IN A BROAD
WARM AIR ADVECTION REGIME BY THE EARLY AFTERNOON HRS SOUTHEAST OF
THE DFW AREA AND JUST EAST OF KACT. CONFIDENCE IS HIGHER IN
DRYLINE INITIATED STORMS THAN WARM AIR ADVECTION INITIATED STORMS
AT THIS TIME...SO DID NOT ACCOUNT FOR EARLIER STORM INITIATION TO
THE SOUTHEAST OF THE DFW AREA WITH THIS FORECAST.
CAVANAUGH
&&
.UPDATE...
THE MCV CURRENTLY CENTERED OVER DENTON COUNTY WILL GRADUALLY
WEAKEN AS IT PROPAGATES EAST ACROSS NORTH TEXAS. AREAS OF LIGHT
PRECIPITATION WITH THE OCCASIONAL LIGHTNING STRIKE CAN BE EXPECTED
EAST OF THIS FEATURE THROUGH EARLY AFTERNOON. WENT AHEAD AND
EXTENDED THE ISOLATED THUNDER OVER THE NORTHEASTERN HALF OF NORTH
TEXAS FOR A FEW HOURS BASED ON THE LATEST RADAR AND SATELLITE
TRENDS...OTHERWISE NO SIGNIFICANT CHANGES ARE PLANNED THIS
MORNING.
30
&&
.PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/
AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS
ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH
TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER
AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO
GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE
LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST
WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS
ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY
WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST
CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER
COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER
THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS
SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF
THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND
YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL
CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR
THIS ACTIVITY.
LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL
WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE
TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE
SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN
OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER
SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE
EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST
TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE
DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH
CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z.
MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH
TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL
CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY
THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST
COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR
THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN
THREAT WITH THUNDERSTORMS THROUGH THIS EVENING.
THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE
THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE
SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA.
THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH
WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO
OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA
INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE
ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST
THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE
THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH
FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON.
HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL
THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND
AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE
PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND
FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND
THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO
CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND
LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD
TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH
SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH
THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF
THE AREA.
BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE
CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL
BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT
FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS
GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH
BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW
POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY
AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM
THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE
BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT
WEEK.
TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS
THROUGH THE NEXT 7 DAYS.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20
WACO, TX 86 63 83 64 83 / 10 10 50 70 30
PARIS, TX 85 59 79 62 79 / 10 10 30 50 20
DENTON, TX 85 63 83 62 80 / 10 10 40 60 20
MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20
DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20
TERRELL, TX 85 62 81 63 82 / 10 10 40 60 30
CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30
TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30
MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1021 AM CDT WED MAY 8 2013
.UPDATE...
THE MCV CURRENTLY CENTERED OVER DENTON COUNTY WILL GRADUALLY
WEAKEN AS IT PROPAGATES EAST ACROSS NORTH TEXAS. AREAS OF LIGHT
PRECIPITATION WITH THE OCCASIONAL LIGHTNING STRIKE CAN BE EXPECTED
EAST OF THIS FEATURE THROUGH EARLY AFTERNOON. WENT AHEAD AND
EXTENDED THE ISOLATED THUNDER OVER THE NORTHEASTERN HALF OF NORTH
TEXAS FOR A FEW HOURS BASED ON THE LATEST RADAR AND SATELLITE
TRENDS...OTHERWISE NO SIGNIFICANT CHANGES ARE PLANNED THIS
MORNING.
30
&&
.AVIATION...
SCATTERED SMALL SHOWERS AND A FEW THUNDERSTORMS WERE NEAR AND
AHEAD OF A MESOSCALE CONVECTIVE VORTEX /MCV/ CENTERED ABOUT 20
MILES NORTHWEST OF KMWL /MINERAL WELLS/. LIFT ASSOCIATED WITH
THIS FEATURE WILL BRING A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE METROPLEX THIS MORNING AS IT MOVES EAST OR
EAST NORTHEAST AT 20 MPH. THE CHANCES OF A THUNDERSTORM AT THE
METROPLEX TAF SITES IS TOO LOW TO MENTION...BUT WILL INCLUDE A
VCSH FOR THE 12-16Z PERIOD. OTHERWISE VFR CONDITIONS ARE EXPECTED
THROUGH MIDNIGHT TONIGHT. LOW CLOUDS ARE EXPECTED TO DEVELOP
ACROSS SOUTH TEXAS OVERNIGHT...AND SPREAD NORTH INTO THE WACO
AREA AFTER 06Z TONIGHT... AND INTO THE METROPLEX AROUND 08Z. MVFR
CEILINGS ARE EXPECTED AND SOME LIGHT FOG /5SM BR/ IS POSSIBLE FOR
THE 08Z-16Z THURSDAY PERIOD. SOUTHERLY WINDS OF 5 TO 10 KNOTS
EARLY THIS MORNING WILL INCREASE TO AROUND 15 KNOTS BEFORE
MIDDAY...WITH GUSTS TO AROUND 25 KNOTS LIKELY. THUNDERSTORMS THAT
ARE EXPECTED TO DEVELOP ALONG THE DRYLINE LATE THIS AFTERNOON ARE
FORECAST TO DISSIPATE AS THEY APPROACH THE I-35 CORRIDOR LATE
TONIGHT.
58
&&
.PREV UPDATE...
.UPDATE...
MCV WHICH WAS MOVING OUT OF THROCKMORTON COUNTY EARLIER IS NOW
CENTERED ALONG THE PALO PINTO/JACK COUNTY LINE AND SEEMS TO BE
AIDING IN MESOSCALE ASCENT ON ITS EAST SIDE. THIS ALSO CORRESPONDS
WELL WITH LEADING EDGE OF THE 850MB THETA-E AXIS WHICH CONTINUES
TO SPREAD NORTHEAST. ISOLATED THUNDERSTORMS CONTINUE AT THIS HOUR
AND HAVE INCREASED SLIGHTLY IN COVERAGE. WILL UPDATE QUICKLY TO
MENTION ISOLATED THUNDERSTORMS THROUGH MID MORNING A LITTLE
FARTHER EAST. NO CHANGES TO POPS. GIVEN THE SMALL CELLS...WILL
LEAVE POPS AT 10 PERCENT.
DUNN
&&
.PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/
AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS
ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH
TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER
AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO
GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE
LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST
WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS
ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY
WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST
CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER
COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER
THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS
SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF
THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND
YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL
CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR
THIS ACTIVITY.
LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL
WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE
TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE
SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN
OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER
SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE
EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST
TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE
DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH
CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z.
MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH
TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL
CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY
THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST
COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR
THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN
THREAT WITH THUNDERSTORMS THROUGH THIS EVENING.
THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE
THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE
SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA.
THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH
WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO
OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA
INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE
ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST
THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE
THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH
FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON.
HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL
THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND
AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE
PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND
FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND
THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO
CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND
LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD
TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH
SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH
THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF
THE AREA.
BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE
CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL
BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT
FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS
GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH
BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW
POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY
AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM
THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE
BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT
WEEK.
TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS
THROUGH THE NEXT 7 DAYS.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20
WACO, TX 86 63 83 64 83 / 10 10 50 70 30
PARIS, TX 85 59 79 62 79 / 10 10 30 50 20
DENTON, TX 85 63 83 62 80 / 10 10 40 60 20
MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20
DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20
TERRELL, TX 85 62 81 63 82 / 10 10 40 60 30
CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30
TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30
MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
627 AM CDT WED MAY 8 2013
.AVIATION...
SCATTERED SMALL SHOWERS AND A FEW THUNDERSTORMS WERE NEAR AND
AHEAD OF A MESOSCALE CONVECTIVE VORTEX /MCV/ CENTERED ABOUT 20
MILES NORTHWEST OF KMWL /MINERAL WELLS/. LIFT ASSOCIATED WITH
THIS FEATURE WILL BRING A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE METROPLEX THIS MORNING AS IT MOVES EAST OR
EAST NORTHEAST AT 20 MPH. THE CHANCES OF A THUNDERSTORM AT THE
METROPLEX TAF SITES IS TOO LOW TO MENTION...BUT WILL INCLUDE A
VCSH FOR THE 12-16Z PERIOD. OTHERWISE VFR CONDITIONS ARE EXPECTED
THROUGH MIDNIGHT TONIGHT. LOW CLOUDS ARE EXPECTED TO DEVELOP
ACROSS SOUTH TEXAS OVERNIGHT...AND SPREAD NORTH INTO THE WACO
AREA AFTER 06Z TONIGHT... AND INTO THE METROPLEX AROUND 08Z. MVFR
CEILINGS ARE EXPECTED AND SOME LIGHT FOG /5SM BR/ IS POSSIBLE FOR
THE 08Z-16Z THURSDAY PERIOD. SOUTHERLY WINDS OF 5 TO 10 KNOTS
EARLY THIS MORNING WILL INCREASE TO AROUND 15 KNOTS BEFORE
MIDDAY...WITH GUSTS TO AROUND 25 KNOTS LIKELY. THUNDERSTORMS THAT
ARE EXPECTED TO DEVELOP ALONG THE DRYLINE LATE THIS AFTERNOON ARE
FORECAST TO DISSIPATE AS THEY APPROACH THE I-35 CORRIDOR LATE
TONIGHT.
58
&&
.UPDATE...
MCV WHICH WAS MOVING OUT OF THROCKMORTON COUNTY EARLIER IS NOW
CENTERED ALONG THE PALO PINTO/JACK COUNTY LINE AND SEEMS TO BE
AIDING IN MESOSCALE ASCENT ON ITS EAST SIDE. THIS ALSO CORRESPONDS
WELL WITH LEADING EDGE OF THE 850MB THETA-E AXIS WHICH CONTINUES
TO SPREAD NORTHEAST. ISOLATED THUNDERSTORMS CONTINUE AT THIS HOUR
AND HAVE INCREASED SLIGHTLY IN COVERAGE. WILL UPDATE QUICKLY TO
MENTION ISOLATED THUNDERSTORMS THROUGH MID MORNING A LITTLE
FARTHER EAST. NO CHANGES TO POPS. GIVEN THE SMALL CELLS...WILL
LEAVE POPS AT 10 PERCENT.
DUNN
&&
.PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/
AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS
ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH
TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER
AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO
GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE
LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST
WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS
ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY
WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST
CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER
COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER
THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS
SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF
THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND
YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL
CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR
THIS ACTIVITY.
LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL
WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE
TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE
SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN
OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER
SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE
EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST
TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE
DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH
CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z.
MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH
TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL
CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY
THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST
COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR
THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN
THREAT WITH THUNDERSTORMS THROUGH THIS EVENING.
THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE
THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE
SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA.
THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH
WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO
OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA
INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE
ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST
THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE
THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH
FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON.
HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL
THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND
AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE
PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND
FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND
THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO
CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND
LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD
TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH
SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH
THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF
THE AREA.
BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE
CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL
BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT
FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS
GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH
BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW
POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY
AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM
THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE
BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT
WEEK.
TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS
THROUGH THE NEXT 7 DAYS.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20
WACO, TX 86 63 83 64 83 / 10 10 50 70 30
PARIS, TX 85 59 79 62 79 / 5 10 30 50 20
DENTON, TX 85 63 83 62 80 / 10 10 40 60 20
MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20
DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20
TERRELL, TX 85 62 81 63 82 / 5 10 40 60 30
CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30
TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30
MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/91
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
548 AM CDT WED MAY 8 2013
.UPDATE...
MCV WHICH WAS MOVING OUT OF THROCKMORTON COUNTY EARLIER IS NOW
CENTERED ALONG THE PALO PINTO/JACK COUNTY LINE AND SEEMS TO BE
AIDING IN MESOSCALE ASCENT ON ITS EAST SIDE. THIS ALSO CORRESPONDS
WELL WITH LEADING EDGE OF THE 850MB THETA-E AXIS WHICH CONTINUES
TO SPREAD NORTHEAST. ISOLATED THUNDERSTORMS CONTINUE AT THIS HOUR
AND HAVE INCREASED SLIGHTLY IN COVERAGE. WILL UPDATE QUICKLY TO
MENTION ISOLATED THUNDERSTORMS THROUGH MID MORNING A LITTLE
FARTHER EAST. NO CHANGES TO POPS. GIVEN THE SMALL CELLS...WILL
LEAVE POPS AT 10 PERCENT.
DUNN
&&
.PREV DISCUSSION... /ISSUED 412 AM CDT WED MAY 8 2013/
AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS
ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH
TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER
AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO
GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE
LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST
WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS
ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY
WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST
CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER
COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER
THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS
SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF
THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND
YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL
CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR
THIS ACTIVITY.
LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL
WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE
TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE
SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN
OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER
SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE
EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST
TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE
DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH
CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z.
MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH
TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL
CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY
THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST
COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR
THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN
THREAT WITH THUNDERSTORMS THROUGH THIS EVENING.
THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE
THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE
SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA.
THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH
WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO
OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA
INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE
ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST
THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE
THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH
FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON.
HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL
THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND
AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE
PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND
FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND
THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO
CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND
LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD
TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH
SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH
THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF
THE AREA.
BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE
CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL
BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT
FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS
GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH
BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW
POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY
AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM
THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE
BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT
WEEK.
TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS
THROUGH THE NEXT 7 DAYS.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20
WACO, TX 86 63 83 64 83 / 10 10 50 70 30
PARIS, TX 85 59 79 62 79 / 5 10 30 50 20
DENTON, TX 85 63 83 62 80 / 10 10 40 60 20
MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20
DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20
TERRELL, TX 85 62 81 63 82 / 5 10 40 60 30
CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30
TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30
MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
412 AM CDT WED MAY 8 2013
.DISCUSSION...
AFTER SEVERAL DAYS OF COOL BUT NICE WEATHER...A WARMER FEW DAYS
ALONG WITH A DECENT SHOT AT THUNDERSTORMS IS IN STORE FOR NORTH
TEXAS. MORNING RADAR IMAGERY SHOWS A THIN BAND OF ELEVATED SHOWER
AND ISOLATED THUNDERSTORM ACTIVITY EXTENDING FROM NEAR WACO TO
GRANBURY THEN BACK WEST OF BRECKENRIDGE. THIS ACTIVITY IS ON THE
LEADING EDGE OF AN 850MB THETA-E AXIS WHICH IS SPREADING NORTHEAST
WITH THE HELP OF A 35KT LOW LEVEL JET. SHORT TERM RAP SOUNDINGS
ACROSS THE REGION INDICATE ABOUT 500J/KG OF ELEVATED INSTABILITY
WHICH HAS RESULTED IN A FEW LIGHTNING STRIKES WITH THE MORE ROBUST
CELLS. THIS ACTIVITY IS LIKELY TO CONTINUE AT LEAST FOR ANOTHER
COUPLE OF HOURS UNTIL THE LOW LEVEL JET SHIFTS NORTHEAST LATER
THIS MORNING. THERE ALSO APPEARS TO BE A WEAK MCV MOVING ACROSS
SOUTHERN THROCKMORTON COUNTY WHERE A SMALL CLUSTER OF
THUNDERSTORMS PERSISTS. THESE WILL LIKELY MOVE INTO STEPHENS AND
YOUNG COUNTIES OVER THE NEXT HOUR. FOR THE EARLY MORNING WILL
CARRY A MENTION OF ISOLATED SHOWERS/THUNDERSTORMS TO ACCOUNT FOR
THIS ACTIVITY.
LATER TODAY...OUR PERSISTENT UPPER LOW OVER THE SOUTHWEST US WILL
WEAKEN A BIT AND SPREAD ONE OF SEVERAL VORTICITY MAXIMA ACROSS THE
TEXAS PANHANDLE. THIS WILL EFFECTIVELY RESULT IN INCREASING LARGE
SCALE FORCING FOR ASCENT ACROSS NORTHWEST TEXAS AND WESTERN
OKLAHOMA THIS AFTERNOON. AT THE SURFACE A WEAK LOW PRESSURE CENTER
SHOULD BE LOCATED ACROSS THE TX/OK PANHANDLES WITH A DRYLINE
EXTENDING SOUTHWARD ACROSS WESTERN OKLAHOMA AND INTO NORTHWEST
TEXAS. WITH MODEST MOISTURE RETURN ESTABLISHED AHEAD OF THE
DRYLINE EXPECT THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE WITH
CAPPING WEAKENING ACROSS THE AREA. SCATTERED SEVERE THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND JUST EAST OF THE DRYLINE BY 00Z.
MOST OF THIS ACTIVITY WILL BE WEST OF OUR CWA INITIALLY BUT WITH
TIME THIS ACTIVITY IS LIKELY TO SPREAD EASTWARD WITH INDIVIDUAL
CELLS MOVING NORTHEAST. MOST LIKELY AREAS TO BE IMPACTED BY
THUNDERSTORMS THROUGH THIS EVENING WOULD BE ACROSS THE NORTHWEST
COUNTIES. GIVEN STEEP LAPSE RATES AND AN INVERTED-V PROFILE NEAR
THE SURFACE...LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN
THREAT WITH THUNDERSTORMS THROUGH THIS EVENING.
THE MORE ACTIVE DAY ACROSS NORTH TEXAS LOOKS LIKE IT WILL BE
THURSDAY AFTERNOON INTO THE OVERNIGHT HOURS. BY THURSDAY THE
SURFACE LOW WILL DRIFT SOUTHEAST TOWARD THE WICHITA FALLS AREA.
THIS IS IN RESPONSE TO A PIECE OF ENERGY OVER THE DAKOTAS WHICH
WILL SLIDE SOUTHWARD INTO THE MIDWEST AND PUSH A COLD FRONT INTO
OKLAHOMA. THE COLD FRONT SHOULD EXTEND FROM NORTHEAST OKLAHOMA
INTO NORTHWEST TEXAS BY AFTERNOON WITH THE DRYLINE LIKELY TO BE
ACROSS OUR NORTHWEST COUNTIES. THIS IS CONSIDERABLY FARTHER EAST
THAN IT WILL BE LOCATED TODAY. AHEAD OF THE COLD FRONT AND DRYLINE
THE ATMOSPHERE ACROSS NORTH TEXAS WILL BE QUITE UNSTABLE WITH
FORECAST MIXED LAYER CAPES AROUND 3200 J/KG DURING THE AFTERNOON.
HIGH RESOLUTION GUIDANCE IS CONSISTENT WITH DEVELOPING SUPERCELL
THUNDERSTORMS INITIALLY IN THIS UNSTABLE ENVIRONMENT ALONG AND
AHEAD OF THE DRYLINE AND COLD FRONT. VERY LARGE HAIL WOULD BE THE
PRIMARY THREAT INITIALLY. MODELS DO INDICATE MID/UPPER LEVEL WIND
FIELDS WEAKEN SUBSTANTIALLY THROUGH LATE EVENING HOWEVER...AND
THIS SUGGESTS THAT INITIAL SUPERCELLULAR THUNDERSTORMS MAY TEND TO
CLUSTER OR ORGANIZE INTO AN MCS. WITH VERY WEAK WIND FIELDS AND
LACK OF SUBSTANTIAL LOW LEVEL JET...ANY CLUSTER OF STORMS WOULD
TEND TO PROPAGATE INTO THE AXIS OF HIGHEST INSTABILITY...WHICH
SHOULD BE LOCATED ACROSS THE SOUTH/SOUTHEAST HALF OF THE CWA. WITH
THAT THINKING...WILL HAVE HIGH POPS THU/THU NIGHT ACROSS MUCH OF
THE AREA.
BY FRIDAY...IF A LARGE COMPLEX OF STORMS HAS MOVED THROUGH...THE
CHANCES FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL
BE LOW DESPITE THE FRONT BEING IN THE AREA. GIVEN THE CURRENT
FORECAST OF A COMPLEX OF STORMS THURSDAY NIGHT...WILL LEAVE POPS
GENERALLY LOWER THAN GUIDANCE FOR FRIDAY ACROSS THE AREA...WITH
BEST CHANCES IN THE SOUTHERN HALF OF THE CWA. WILL HAVE SOME LOW
POPS THROUGH SATURDAY GIVEN THE PROXIMITY TO THE FRONTAL BOUNDARY
AND LIKELY SOME WEAK FORCING FROM EJECTING PIECES OF ENERGY FROM
THE MAIN LOW. THIS LOW ACTUALLY APPEARS TO RETROGRADE ACROSS THE
BAJA CALIFORNIA AND MAY PROVIDE ADDITIONAL RAIN CHANCES LATER NEXT
WEEK.
TEMPERATURES WILL GENERALLY BE AT OR SLIGHTLY ABOVE SEASONAL NORMS
THROUGH THE NEXT 7 DAYS.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 85 65 82 65 81 / 10 10 50 60 20
WACO, TX 86 63 83 64 83 / 10 10 50 70 30
PARIS, TX 85 59 79 62 79 / 5 10 30 50 20
DENTON, TX 85 63 83 62 80 / 10 10 40 60 20
MCKINNEY, TX 85 62 81 62 80 / 10 10 40 60 20
DALLAS, TX 86 67 84 66 82 / 10 10 50 60 20
TERRELL, TX 85 62 81 63 82 / 5 10 40 60 30
CORSICANA, TX 85 62 82 65 83 / 10 10 40 70 30
TEMPLE, TX 85 63 81 65 84 / 10 10 50 70 30
MINERAL WELLS, TX 87 63 86 62 79 / 10 20 50 50 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
953 PM CDT THU MAY 9 2013
.UPDATE...
MADE SOME ADJUSTMENTS TO POPS...PRECIPITATION TIMING AND
PLACEMENT OF HIGHER QPF AMOUNTS BASED ON RADAR TRENDS AND
OBSERVATIONS. LATEST NAM FOLLOWING TRENDS OF HI-RESOLUTION/RAPID
UPDATE MODELS IN LINGERING A FRONTOGENETIC BAND OF PCPN ACROSS
EASTERN WI INTO FRIDAY MORNING. WILL LOOK AT NEED FOR RAISING
CHANCE POPS FOR A TIME BETWEEN 12Z AND 15Z FRIDAY.
&&
.AVIATION/06Z TAFS/...
IFR CIGS HAVE SPREAD EASTWARD WITH COOLING TEMPERATURES AND
STEADY PRECIPITATION THAT WILL LINGER THROUGH THE OVERNIGHT AS
SURFACE LOW PASSES TO THE SOUTH ACROSS NRN IL. WINDS AT KMSN AND
KUES A LITTLE MORE EASTERLY THAN KMKE AND KENW...WHICH MAY ALSO GO
MORE ENE AND EASE AS SURFACE LOW PASSES JUST TO THE SOUTH...THEN
BACK TO THE NORTH-NORTHEAST AND INCREASE WITH GUSTS TO 20-25 KNOTS
BEHIND THE LOW AS IT MOVES AWAY TO THE SOUTHEAST. EXPECT CIGS TO
RISE TO MVFR LEVELS BY MID TO LATE MORNING...WITH SOME CLEARING
POSSIBLE AFTER 00Z SATURDAY...THOUGH CLOUDS WILL BE MOVING BACK
INTO THE REGION AFTER 06Z AHEAD OF NEXT VIGOROUS SHORT WAVE.
&&
.MARINE...
SOME CONCERN FOR NEED TO UP TO A GALE WARNING IN TIGHTER PRESSURE
GRADIENT ACROSS NRN ZONES AS LATEST RAP SOUNDINGS FOR SBM SHOW 35
TO 40 KNOT WINDS AROUND 1300-1500 FT THROUGH AROUND 12Z FRIDAY.
LATEST NAM SOUNDINGS ONLY HAS MIXED LAYER TAPPING TO 30 TO 33
KNOT WINDS. ELEVATED SBM C-MAN HAS GUSTED TO 36 KNOTS. WILL
CLOSELY MONITOR TO SEE IF GUSTS AT/ABOVE 35 KNOTS BECOME FREQUENT
ENOUGH FOR A WARNING. OTHERWISE SMALL CRAFT UNTIL FRIDAY EVENING
STILL LOOKS ON TRACK WITH WINDS EASING TO UNDER CRITERIA LATE IN
THE AFTERNOON... WITH 00Z SATURDAY EXPIRATION ALLOWING WAVES TO
SUBSIDE.
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT THU MAY 9 2013/
SHORT TERM...
TONIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
SHOWERS HAVE SPREAD INTO MOST OF THE AREA...AS 500MB SHORTWAVE
TROUGH APPROACHES FROM THE WEST. THIS FEATURE...ALONG WITH LOW TO
MID LEVEL FRONTOGENESIS RESPONSE FIELDS...WILL SHIFT EASTWARD
THROUGH THE AREA TONIGHT...EXITING FRIDAY MORNING. STRONG UPWARD
VERTICAL MOTION IS ANTICIPATED WITH THESE FEATURES. AREA FORECAST
SOUNDINGS SHOW DEEP MOISTURE IN AIR COLUMN...WITH MOIST ADIABATIC
PROFILES. WILL CONTINUE HIGH POPS FOR PERIODS OF SHOWERS THROUGH
MOST OF TONIGHT...BEFORE TAPERING OFF FRIDAY MORNING. ADDED ISOLATED
THUNDER TO THE FAR SOUTHERN COUNTIES...AS RADAR SHOWING SOME
CONVECTIVE ACTIVITY SLIDING NORTHWARD FROM NORTHERN ILLINOIS.
BACKDOOR/PNEUMONIA FRONT WILL CONTINUE TO SLIDE SOUTHWESTWARD ACROSS
THE AREA THROUGH EARLY THIS EVENING...AS LOW PRESSURE STRENGTHENS AS
IT SHIFTS EASTWARD ACROSS NORTHERN ILLINOIS. THIS WILL BRING A QUICK
WIND SHIFT AND DROP IN TEMPERATURES AS IT MOVES THROUGH. BRISK
NORTHEAST WINDS ARE EXPECTED BEHIND THIS FEATURE BY EARLY
EVENING...LINGERING THROUGH FRIDAY WITH TIGHT PRESSURE GRADIENT FROM
STRENGTHENING LOW TO THE SOUTHEAST. COLDER TEMPERATURES ARE EXPECTED
TO LINGER TONIGHT AND FRIDAY ACROSS THE AREA...AIDED BY THE BRISK
NORTH TO NORTHEAST WINDS. HIGHS WILL ONLY REACH THE 50S ON
FRIDAY...AS COLD AIR ADVECTION TAKES HOLD OF THE AREA.
FRIDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
WEAK HIGH PRESSURE AND CLEARING SKIES WILL PREVAIL FRIDAY EVENING
IN THE WAKE OF DEPARTING LOW PRESSURE AND RAIN FROM TNT AND FRI
AM. A LARGE POLAR TROUGH WILL THEN DIG SEWD INTO THE GREAT LAKES
FOR THE WEEKEND. THE SFC LOW PRESSURE AREA WILL REMAIN IN SRN
CANADA BUT ITS COLD FRONTAL PASSAGE WILL OCCUR SAT AM. A NARROW
BAND OF HIGH 1000-500 MB RH AND LOW TO MID LEVEL FRONTOGENESIS
WILL BE PRESENT ALONG THE FRONT...BUT OVERALL PCPN CHANCES ARE LOW
WITH THE BETTER DYNAMICS TO THE NORTH.
BRISK NWLY WINDS AND COOL TEMPS WILL PREVAIL ON SAT AND THEN
GRADUALLY WEAKEN SAT NT. LARGE POLAR HIGH PRESSURE WILL THEN
APPROACH FROM THE PLAINS FOR SUN AFTERNOON AND NIGHT. 1000-500 MB
THICKNESSES WILL RANGE FROM 528-537 DM FOR THE WEEKEND WITH 850 MB
TEMPS RANGING FROM -1C TO -5C. LOW TEMPS IN THE 30S ARE FORECAST
FOR SAT NT AND SUN NT AND WILL PROBABLY SEE AREAS OF FROST
DEVELOP. IF WIDESPREAD LOW TO MID 30S ARE FORECAST...A FROST
ADVISORY WILL BE CONSIDERED FOR THOSE EARLY MORNINGS. HIGH TEMPS
IN THE COOL MID 50S FOR THE WEEKEND.
LONG TERM...
MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM
THE LARGE POLAR TROUGH WILL MOVE EAST AND NORTH OF THE GREAT LAKES
EARLY NEXT WEEK. ZONAL FLOW WILL THEN BECOME ESTABLISHED OVER THE
NRN USA FOR THE REMAINDER OF THE WEEK AS LOW PRESSURE MOVES EWD
ACROSS SRN CANADA. SSWLY SFC FLOW WILL PREVAIL EARLY IN THE WEEK
WITH THE PASSAGE OF A WARM FRONT AND A RETURN OF SUMMER LIKE
TEMPERATURES. SMALL POPS ARE FORECAST FOR WARM ADVECTION PCPN. A
TRAILING COLD FRONT WILL THEN STALL AND BECOME STATIONARY IN THE
VICINITY OF SRN WI AND NRN IL...THUS CHANCES OF TSTORMS ARE
FORECAST.
AVIATION/00Z TAFS/...
SHOWERS WILL CONTINUE TO AFFECT THE TAF SITES LATE THIS AFTERNOON
AND TONIGHT...AS TROUGH OF LOW PRESSURE SLOWLY MOVES EAST THROUGH
THE AREA. EXPECT CEILINGS AND VISIBILITIES TO FALL BELOW FUEL
ALTERNATE THRESHOLDS BY MID EVENING...LASTING INTO EARLY FRIDAY.
CEILINGS WILL DROP TO IFR LEVELS DURING THIS TIME.
GUSTY NORTHEAST WINDS WILL REACH TAF SITES BETWEEN 23Z THURSDAY AND
01Z FRIDAY...WITH COLD FRONT SLIDING SOUTHWARD. THESE WINDS WILL
REMAIN GUSTY TONIGHT INTO FRIDAY...AS STRENGTHENING LOW PRESSURE
PASSES SOUTHEAST OF THE AREA. GUSTS UP TO 25 KNOTS ARE EXPECTED AT
TIMES. THE SHOWERS SHOULD DIMINISH BY MID TO LATE MORNING
FRIDAY...WITH CEILINGS RISING ABOVE FUEL ALTERNATE THRESHOLDS BY THE
AFTERNOON. SHOULD SEE MIXING OUT OF CEILINGS BY LATE AFTERNOON.
MARINE...
COLD FRONT SHIFTING SOUTHWARD ACROSS THE NEARSHORE WATERS LATE THIS
AFTERNOON AND EARLY THIS EVENING WILL BRING GUSTY NORTHEAST TO NORTH
WINDS. THESE WINDS WILL LINGER TONIGHT INTO FRIDAY...AS
STRENGTHENING LOW PRESSURE MOVES SOUTHEAST OF THE AREA. GUSTS UP TO
30 KNOTS ARE EXPECTED AT TIMES TONIGHT INTO FRIDAY. THESE WINDS WILL
GENERATE HIGH WAVES...LINGERING INTO FRIDAY EVENING BEFORE
SUBSIDING. THUS...A SMALL CRAFT ADVISORY IS IN EFFECT INTO FRIDAY
EVENING.
A SMALL CRAFT ADVISORY MAY BE NEEDED LATE SATURDAY MORNING INTO THE
AFTERNOON...AS GUSTY NORTHWEST WINDS MOVE INTO THE REGION BEHIND A
DEPARTING COLD FRONT. THESE WINDS MAY GENERATE HIGH WAVES TOWARD THE
OPEN WATERS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT FRIDAY FOR LMZ643>646.
&&
$$
UPDATE...REM
TONIGHT/FRIDAY AND AVIATION/MARINE...WOOD
FRIDAY NIGHT THROUGH THURSDAY...GEHRING
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
135 AM CDT FRI MAY 10 2013
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
SHOWERS HAVE MOVED EAST OF MOST CENTRAL AND SOUTHERN SITES...BUT
EXPECT A NEW WAVE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE
NEXT FEW HOURS AND AFFECT TERMINAL FROM KLIT SOUTHWARD.
MEANWHILE...A BAND OF SHRA/TSRA WILL MOVE FROM KFYV EAST TO KHRO
AND KBPK. EXPECT AT LEAST MVFR CONDITIONS FOR 3-4 HOURS WITH
PREVAILING SHRA AND OCCASIONAL TSRA. WOULD NOT BE SURPRISED TO SEE
CONDITIONS DROP TO IFR LEVELS...ESPECIALLY VSBY.
SHOWERS AND THUNDERSTORMS WILL CLEAR ALL TERMINALS BY 10-12Z OR
SO...WITH VFR CONDITIONS RETURNING THEREAFTER. MORE STORMS MAY
FIRE IN SOUTHEAST ARKANSAS THIS EVENING AND HAVE VCSH MENTIONED
FROM 00Z SAT ONWARD AT KPBF AND KLLQ TO ACCOUNT FOR THIS.
&&
.PREV DISCUSSION... /ISSUED 858 PM CDT THU MAY 9 2013/
UPDATE...
CONVECTION CONTINUES OVER THE SOUTH AT THIS TIME AS UPPER LEVEL
ENERGY APPROACHES FROM TEXAS. OTHER WEAKER CONVECTION ACROSS THE
NORTH IS WORKING OVER THE SAME GENERAL AREA THAT SAW SOME
THUNDERSTORMS THIS MORNING. ACTIVITY HAS BEEN SLOWLY WEAKENING BUT
POTENTIAL REMAINS FOR SOME LARGER HAIL THROUGH THE NIGHT.
SOME STORMS LIKELY WILL PRODUCE BRIEF HEAVY DOWNPOURS BUT NO
HEADLINES ARE ANTICIPATED AT THIS TIME. AFOREMENTIONED WAVE STILL
OVER NORTHEAST TEXAS AND HAS TO ROTATE THROUGH THE STATE TONIGHT
AND WILL KEEP POPS ON THE HIGH SIDE AS A RESULT.
ATTENTION WILL ALSO DIRECTED TOWARDS THE AFOREMENTIONED COLD
FRONT CURRENTLY STRETCHING FROM CENTRAL OKLAHOMA THROUGH CENTRAL
MISSOURI. THE BOUNDARY WILL BE A SLOW MOVER AND WILL ONLY REACH
FAR NORTHWEST ARKANSAS BY MORNING KEEPING POPS ELEVATED ACROSS
THIS PART OF THE STATE AS WELL.
EVENING UPDATE WILL BE TO REWORK POPS AND QPF BASED ON CURRENT
RADAR TRENDS AND A QUICK PEEK AT THE NEW NAM AND THE HRRR MODELS.
ALL UPDATES OUT.
PREV DISCUSSION... /ISSUED 305 PM CDT THU MAY 9 2013/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
CONVECTION THAT AFFECTED PARTS OF THE AREA THIS MRNG...HAD SHIFTED E
OF THE REGION BY MIDDAY. SUBSIDENCE BEHIND THIS ACTIVITY HAS LIMITED
ADDITIONAL FORMATION ACRS AR THRU MID AFTN. IT ALSO ALLOWED CLOUDS
TO DCRS OVR MUCH OF NRN AND ERN AR...WITH MID AFTN TEMPS IN THE UPR
70S TO LOWER 80S. INCRSG CLOUDS OVR SWRN AR HELD READINGS IN THE
LOWER AND MID 70S. WL KEEP MINIMAL POPS OVR MOST OF THE FA EARLY
THIS EVENING.
MEANWHILE...A COMPLEX OF STORMS CONTD TO ORGANIZE ACRS CNTRL/ERN TX
THIS AFTN...ASSOCD WITH ANOTHER UPR LVL WV MOVG ACRS THE SRN PLAINS.
AN ADDITIONAL CLUSTER OF STORMS HAS FORMED ALONG THE RED RVR IN SERN
OK. EXPECT SOME THIS ACTIVITY TO AFFECT WRN AR TOWARD SUNSET.
ADDITIONAL CONVECTION WL FORM TNGT AS THE AFOREMENTIONED UPR IMPULSE
TRACKS INTO AR...AND ALONG A SLOW MOVG CDFNT APCHG FM THE CNTRL
PLAINS. CURRENT DATA SUGGESTS THE BNDRY WL BE ALONG THE I-44
CORRIDOR EARLY FRI MRNG. CANNOT RULE OUT A FEW STRONG/SVR STORMS
TNGT...WITH LARGE HAIL AND WINDS THE MAIN CONCERNS.
APPEARS WE WL SEE A LULL IN THE RAINFALL LATER FRI MRNG/EARLY AFTN
AS THE FIRST ROUND OF STORMS WORKS E OF THE AREA. THE CDFNT WL CONT
TO DRIFT EVER SO SLOLY SEWD INTO CNTRL AR LATER ON FRI AS THE BNDRY
INITIALLY ENCOUNTERS SWLY FLOW ALOFT. SCTD SHRA/TSRA WL BE POSSIBLE
AHEAD OF THE FNT INTO FRI NGT. RAIN CHCS WL DCRS FM THE NW AS THE
NGT PROGRESSES AND THE FNT SHIFTS SE OF AR.
DRIER CONDS RETURN FOR SAT WITH TEMPS CLOSE TO NORMAL FOR THIS TIME
OF YEAR. A SECONDARY CDFNT WL SWEEP SWD THRU AR SAT NGT...FOLLOWED
BY COOLER AND MUCH DRIER AIR. AN UPR LVL IMPULSE IS PROGGED TO DROP
SEWD INTO THE AREA LATER SUN NGT...BRINGING AN INCRS IN CLOUDS. WL
KEEP THE FCST DRY ATTM AND MONITOR MODEL TRENDS IN THE COMING DAYS
FOR THE POSSIBLE INCLUSION OF SMALL RAIN CHCS.
LONG TERM...MONDAY THROUGH THURSDAY
THE EXTENDED FORECAST STARTS WITH A LARGE SURFACE HIGH PRESSURE
SYSTEM OVER THE CENTRAL U.S...WHILE A LARGE AND BROAD UPPER TROUGH
OVER THE NE TO SE U.S. WEATHER WILL BE DRY WITH JUST A BIT COOLER
TEMPS TO START. MONDAY THE SURFACE HIGH PRESSURE CENTERS OVER THE
SOUTHEASTERN PLAINS...AS THE LARGE UPPER TROUGH OVER THE EAST COAST
MOVES A BIT MORE EAST. THIS WILL BRING DRY WEATHER AND TEMPS CLOSER
TO NORMAL VALUES. ON TUESDAY CONTINUED DRY WITH WARMING TEMPS AS THE
SURFACE HIGH PRESSURE HAS MOVED OFF TO THE EAST OF AR. ON WEDNESDAY
MODELS ARE DEPICTING AN UPPER SYSTEM OVER THE SOUTHERN PLAINS...AND
WITH RETURN FLOW TO THE AREA...SOME CONVECTION SHOULD BE SEEN MAINLY
OVER TEXAS. THE FORECAST WILL REMAIN DRY OVER AR WITH WARMER TEMPS.
LATER WEDNESDAY NIGHT AND THURSDAY...A SLIGHT CHANCE OF CONVECTION
IS BACK IN THE FORECAST AS THIS UPPER SYSTEM SLOWLY MOVES EAST AND
AFFECTS AR. TEMPS WILL REMAIN WARM WEDNESDAY AND THURSDAY. OVERALL
CONFIDENCE IS AVERAGE WITH MODEL TRENDS BUT TIMING COULD CHANGE IN
FUTURE MODEL RUNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 76 54 73 47 / 40 20 10 10
CAMDEN AR 81 60 76 51 / 50 30 20 10
HARRISON AR 70 51 70 45 / 30 10 10 10
HOT SPRINGS AR 79 58 75 52 / 50 20 10 10
LITTLE ROCK AR 80 58 75 54 / 50 20 10 10
MONTICELLO AR 81 62 77 53 / 60 30 20 10
MOUNT IDA AR 77 54 75 48 / 50 20 10 10
MOUNTAIN HOME AR 72 51 72 45 / 30 10 10 10
NEWPORT AR 77 55 73 50 / 50 20 10 10
PINE BLUFF AR 80 61 75 53 / 50 30 20 10
RUSSELLVILLE AR 79 52 75 46 / 40 20 10 10
SEARCY AR 79 56 74 48 / 50 20 10 10
STUTTGART AR 79 59 73 53 / 50 20 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...64
AREA FORECAST DISCUSSION
NWS TUCSON AZ
230 AM MST FRI MAY 10 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM NEAR THE AREA WILL HELP BRING A
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS THROUGH SATURDAY.
DRIER WITH A STRONG HEATING TREND EARLY IN THE NEW WEEK...HOWEVER
STILL A FEW ISOLATED THUNDERSTORMS NEAR THE EASTERN MOUNTAINS.
&&
.DISCUSSION...RESIDUAL ENERGY SAGGING BACK INTO THE DESERT SOUTHWEST
FOR ANOTHER COUPLE OF DAYS WITH WHAT`S LEFT OF THE ENERGY SHIFTING
THROUGH NORTHERN AND CENTRAL SONORA OVER THE NEXT 36 HOURS. SOME MID
LEVEL MOISTURE IN PLACE AS EVIDENCED BY DEBRIS CLOUD WITH SLOW
INCREASE IN BLENDED TOTAL PRECIPITABLE WATER TRENDS FROM .45 TO .6
ON SATELLITE SOUNDER ESTIMATES. SHOULD BE ENOUGH FOR A JUMP IN
CONVECTION THIS AFTERNOON WITH SUFFICIENT CAPE AND FLOW FOR SOME
STORMS TO SPREAD INTO VALLEYS THIS AFTERNOON. DRY MICROBURSTS A
POTENTIAL CONCERN WITH SOME ORGANIZED BLOWING DUST POSSIBLE. A CLOSE
LOOK AT THE 12Z SOUNDING AND LATEST HRRR TRENDS AS WE CONTINUE TO
FINE TUNE CURRENT FORECAST ALREADY WELL ABOVE CLIMO CONVECTION.
ECMWF AND NAMDNG5 TRENDS SHOWS THE LOW STALLING AND FILLING THROUGH
CHIHUAHUA AND SONORA OVER THE WEEKEND WITH A FEW STORMS AROUND
SOUTHEAST ARIZONA SATURDAY. AS THE REMAINS CONTINUE TO SLOWLY FILL
IT SHOULD SHEAR THROUGH AS IT REGAINS MODEST HIGHER LATITUDE SUPPORT
BY TUESDAY OR WEDNESDAY. NEARLY ZONAL GEOMETRY BUT NET GAIN IN
HEIGHT AND THICKNESS TRENDS ALONG WITH A DRYING TREND SHOULD ALLOW
DAYTIME HIGHS 5 TO 8 DEGREES ABOVE CLIMO THE SECOND HALF OF NEXT
WEEK.
&&
.AVIATION...SKC-SCT150. AFT 17Z...SCT TO LCLY BKN 6-10KFT AGL MNLY E
AND S OF KTUS. ISOLD-SCT TSRA/-SHRA DVLPG OVER THE MTNS WITH SOME
STORMS MOVG W-SW INTO THE VALLEYS. BRIEF WIND GUSTS UP TO 40 KTS MAY
OCCUR NEAR TSTMS. SFC WIND THIS AFTERNOON WLY/NWLY 10-15 KTS WITH
GUSTS TO NEAR 25 KTS...STRONGEST E AND S OF KTUS.
OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS ESPECIALLY EAST OF TUCSON THROUGH SATURDAY. THERE
IS THE POTENTIAL FOR GUSTY WINDS ASSOCIATED WITH THUNDERSTORMS...
PARTICULARLY THIS AFTERNOON AND EVENING...AS A LOW PRESSURE SYSTEM
MOVES SOUTH INTO SONORA MEXICO. FIELD CREWS ARE ENCOURAGED TO
MONITOR THE LATEST FORECASTS REGARDING THIS SCENARIO. OTHERWISE...
GUSTY EAST TO SOUTHEAST WINDS WILL OCCUR SATURDAY. CRITICAL FIRE
WEATHER THRESHOLDS ARE NOT FORECAST TO BE MET AT THIS TIME.
THEREAFTER...EXPECT DRY CONDITIONS WITH ABOVE NORMAL DAYTIME
TEMPERATURES SUNDAY THROUGH THURSDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/GLUECK
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1113 PM MDT THU MAY 9 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 247 PM MDT THU MAY 9 2013
ELONGATED UPPER LOW FROM SRN CA ACROSS THE 4 CORNERS TO ERN CO WAS
GETTING STRETCHED APART THIS AFTERNOON...AS THE EASTERN PORTION
MOVES INTO THE PLAINS WHILE THE WESTERN PORTION DROPS SOUTHWARD.
CONVECTION WAS A LITTLE SLOW GETTING GOING TODAY...BUT RECENT KGJX
RADAR SHOWED ECHOES BUILDING ALONG THE TAVAPUTS/ROAN PLATEAUS TO THE
FLATTOPS...AND OVER THE CENTRAL AND SOUTHERN MTNS. INSTABILITY
LIKELY THE DRIVING FORCE THOUGH RAP MODEL INDICATED SOME 700-500 MB
LAYER CONVERGENCE SOUTH OF I-70 AND UNDER THE DEFORMATION/UPPER LOW
AXIS ALOFT. ISOLATED THUNDERSTORMS WILL BE POSSIBLE WITH GUSTY WINDS
AND PERHAPS SOME GRAUPEL. WILL KEEP THE CURRENT WINTER HIGHLIGHTS
GOING THOUGH PRECIPITATION LIKELY TO BE QUITE VARIABLE GIVEN THE
CONVECTIVE NATURE OF THE SHOWERS.
THE DEFORMATION ZONE SINKS SOUTH OF OUR AREA THIS EVENING AND
TONIGHT. WITH ITS EXIT AND THE LOSS OF DAYTIME HEATING...EXPECT
SHOWERS TO DIMINISH BY LATE EVENING.
A SHORTWAVE DISTURBANCE DROPPING DOWN ACROSS WRN MT THIS AFTERNOON
WILL REACH OUR FORECAST AREA BY FRI MORNING. NE UT/NW CO SHOULD SEE
CLOUDS BACK ON THE INCREASE BY SUNRISE. WEAK MOISTURE TRANSPORT IN
THE NORTHERN FLOW ALONG THIS PASSING WEAK DISTURBANCE AND DAYTIME
INSTABILITY SHOULD TRIGGER A ROUND OF AFTERNOON SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS FRIDAY AFTERNOON...MAINLY OVER THE HIGHER
TERRAIN. SNOW WILL GENERALLY BE CONFINED TO ABOVE 9500-10K FT. HIGH
TEMPS FRIDAY WILL BE WARMER THAN TODAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 247 PM MDT THU MAY 9 2013
A HIGHLY AMPLIFIED PATTERN THROUGH THE WEEKEND FLATTENS EARLY NEXT
WEEK. THERE IS HIGH FORECAST CONFIDENCE THROUGH MONDAY...THEN MODELS
SHOW INCREASING SPREAD IN FORECAST DETAILS.
A POSITIVELY TILTED RIDGE AXIS AMPLIFIES FROM THE EASTERN PACIFIC
INTO THE NORTHERN ROCKIES. THEN SLOWLY PROGRESSES UNTIL IT IS
OVERHEAD ON MONDAY. A PORTION OF THE LOW PRESSURE SYSTEM THAT
BROUGHT SHOWERS ON WEDNESDAY INTO THURSDAY IS CUTOFF IN SONORA
MEXICO. NEAR NORMAL TEMPERATURES ON SATURDAY WILL RISE WELL ABOVE
NORMAL BY MONDAY. THE WARMING AFTERNOON TEMPERATURES AND MARGINAL
MOISTURE LOOK TO OVERCOME SUBSIDENCE ON SATURDAY FOR SCATTERED
MAINLY MOUNTAIN THUNDERSTORMS. INCREASING SUBSIDENCE ON SUNDAY AND
MONDAY WITH MOISTURE DIMINISHING DUE TO CONVECTIVE VENTILATION
DIMINISH THE CHANCES OF MOUNTAIN SHOWERS. MONDAY AFTERNOON
TEMPERATURES WILL RISE ABOUT 10 DEGREES ABOVE NORMAL.
ON MONDAY A TROUGH WORKS INTO BC-WASHINGTON AND LIFTS THROUGH THE
NORTHERN ROCKIES ON TUESDAY. THIS BREAKS DOWN THE LOCAL RIDGE AND
ALSO ENTRAINS THE SONORA LOW...BOTH OF WHICH MAY INCREASE DIURNAL
THUNDERSTORM COVERAGE FOR TUESDAY INTO WEDNESDAY. BY THURSDAY BOTH
THE EC AND GFS ARE DIGGING A SHALLOW TROUGH ALONG THE WEST COAST
THAT MAY THREATEN INCREASED SHOWERS TOWARDS THE NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1113 PM MDT THU MAY 9 2013
EXPECT VFR CONDITIONS ACROSS THE REGION THROUGH 18Z FRIDAY.
RESIDUAL MOISTURE AND DAY TIME HEATING WILL YIELD SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS. AS A RESULT...LOOK
FOR AREAS OF MOUNTAIN OBSCURATION AND GUSTY OUTFLOW WINDS IN THE
HIGH COUNTRY. THUNDERSTORMS WILL LARGELY REMAIN ANCHORED TO THE
HIGHER TERRAIN...THOUGH THERE IS A CHANCE THAT KEGE...KASE...KGUC
...KDRO AND KPSO MAY EXPERIENCE BRIEF SHOWERS OR THUNDERSTORMS
FROM 22Z FRI TO 03Z SAT AS DIURNAL CIRCULATIONS BREAK DOWN. THERE
IS A LOW END CHANCE THAT MVFR CONDITIONS WILL RESULT FROM THIS
ACTIVITY. ELSEWHERE...VFR CONDITIONS WILL CONTINUE.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...NL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1217 AM CDT FRI MAY 10 2013
...UPDATED FOR THE 06Z TAFS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 221 PM CDT THU MAY 9 2013
AN ELONGATED MID LEVEL VORTICITY AXIS WAS FOUND ACROSS THE CENTRAL
PLAINS TODAY COMPLETE WITH MOISTURE AND FAIRLY COOL TEMPERATURES.
UPPER AIR OBSERVATIONS AND RAP ANALYSIS INDICATED 500/700MB
TEMPERATURES AROUND -17C/0C RESPECTIVELY. SOME INSOLATION THROUGH
EARLY AFTERNOON RESULTED IN SURFACE TEMPERATURES WARMING INTO THE
UPPER 60S TO NEAR 70 DEGREES PARTICULARLY SOUTH OF THE ARKANSAS
RIVER. THE MID LEVEL MOISTURE AXIS WAS FOUND TO BE CENTERED FROM THE
CENTRAL ROCKIES THROUGH NORTHERN KANSAS AND MUCH OF NEBRASKA. THIS
LINED UP FAIRLY WELL WITH THE MEAN 500-700MB DEFORMATION AXIS. THE
SURFACE FRONT HAD PUSHED WELL SOUTH OF THE REGION DOWN INTO SOUTHERN
OKLAHOMA, SO SURFACE-BASED INSTABILITY WAS VERY LOW ACROSS
SOUTHWESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 221 PM CDT THU MAY 9 2013
THE MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES, COVERAGE, AND
INTENSITY THIS EVENING. THE MENTIONED DEFORMATION AXIS WILL LINGER
ACROSS SOUTHEASTERN COLORADO AND WESTERN KANSAS THROUGH THIS
EVENING. THE UPDATED FORECAST POP/WX GRIDS WILL REFLECT THE HRRR
MODEL THINKING OF WEAK UPRIGHT CONVECTION FORMING NEAR A VORTICITY
CENTER ACROSS SOUTHEASTERN COLORADO. A LOOSELY ORGANIZED CLUSTER OF
CONVECTION COULD DEVELOP A COLD POOL ALLOWING THE CLUSTER OF
CONVECTION TO MOVE INTO THE SOUTHWESTERN QUARTER OR THIRD OF THE DDC
FORECAST AREA (SOUTH AND WEST OF A LAKIN TO MEADE LINE, ROUGHLY).
THE ABSENCE OF APPRECIABLE SURFACE-BASED CAPE IS EXPECTED TO KEEP
CONVECTION BELOW SEVERE LIMITS...BUT SOME GUSTS TO 50 OR 55 MPH WILL
BE POSSIBLE IF LOOSELY ORGANIZED COLD POOLS DEVELOP. ANY STORMS
WHICH IMPACT FAR SOUTHWESTERN KANSAS SHOULD BE EXITING THE AREA BY
LATE EVENING.
ON FRIDAY...WESTERN KANSAS WILL BE UNDER AN INCREASED INFLUENCE OF
NORTHWEST FLOW ALOFT AS THE MID LEVEL SHEAR AXIS CONTINUES TO PUSH
SOUTH INTO TEXAS. THIS IS EXPECTED TO RESULT IN MORE TRANQUIL
SENSIBLE WEATHER. THAT BEING SAID...MID LEVEL TEMPERATURES WILL
STILL BE COOL (700MB TEMPERATURE -2 TO 0C)...AND MIXING
CONDENSATION LEVELS WILL BE LOW AS INSOLATION ALLOWS SURFACE TEMPS
TO WARM INTO THE UPPER 60S. THE RESULT WILL BE DEVELOPMENT OF
CUMULUS AND PERHAPS AN ISOLATED SHOWER OR TO LATE IN THE DAY. THE
OFFICIAL FORECAST WILL BE DRY AS THERE WILL BE AN ABSENCE OF UPPER
LEVEL FORCING FOR ASCENT TO PROMOTE ANY ORGANIZATION OF
CONVECTION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CDT THU MAY 9 2013
THE WEATHER PICTURE THIS WEEKEND WILL DEPICT AN UPPER LEVEL LONG
WAVE TROUGH DIGGING ACROSS THE NORTHEAST UNITED STATES AND AN UPPER
LEVEL RIDGE BUILDING ACROSS THE WESTERN UNITED STATES. MEANWHILE,
THE UPPER LEVEL LOW THAT ASSISTED IN SEVERE STORM DEVELOPMENT ACROSS
OUR AREA THE LAST COUPLE OF NIGHTS WILL SPLIT OFF FROM THE FLOW AND
MIGRATE TOWARDS NORTHERN MEXICO. THESE FEATURES WILL PLACE THE
CENTRAL HIGH PLAINS UNDER NORTHWEST FLOW ALOFT. THIS PATTERN USUALLY
GIVES WAY TO FAIR WEATHER DAYS ACROSS WESTERN KANSAS. HOWEVER, RAIN
CHANCES WILL BE POSSIBLE SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE
AT THE SURFACE WILL BE THE DOMINATE FEATURE ACROSS WESTERN KANSAS
FRIDAY NIGHT INTO SATURDAY WITH A SECOND AREA OF HIGH PRESSURE
OOZING DOWN FROM THE NORTH SATURDAY NIGHT INTO SUNDAY. A COLD FRONT
WILL BE FOUND IN BETWEEN THESE TWO AREAS OF HIGH PRESSURE ALLOWING
SOME LIFT TO OCCUR ACROSS THE PLAINS SATURDAY NIGHT. THE ATMOSPHERE
WILL BE FAIRLY DRY AS THIS FRONT MOVES THROUGH BUT THERE COULD BE A
SHOWER OR TWO THAT FORMS SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
WINDS WILL GENERALLY BE LIGHT AND VARIABLE FRIDAY NIGHT INTO
SATURDAY SHIFTING TO THE NORTH BEHIND THE FRONT SATURDAY NIGHT INTO
SUNDAY. A WEAK UPPER LEVEL SHORTWAVE IS THEN DEPICTED BY THE MODELS
TO MOVE DOWN THROUGH THE NORTHWEST FLOW AND INTO KANSAS SUNDAY. IF
THIS COMES TO FRUITION, THUNDERSTORM WILL BE POSSIBLE ACROSS CENTRAL
KANSAS SUNDAY MORNING SPREADING TOWARDS SOUTH CENTRAL KANSAS AS THE
DAY PROGRESSES. OTHERWISE PARTLY CLOUDY SKIES WILL BE FOUND ACROSS
WESTERN KANSAS. LEE TROUGHING WILL ALSO BE DEVELOPING ACROSS THE
KS/CO BORDER DURING THIS TIME FRAME SHIFTING WINDS TO MORE OF A
SOUTHERLY DIRECTION. LOWS SATURDAY AND SUNDAY MORNING LOOK TO DIP
INTO THE 40S WITH HIGHS IN THE 70S SATURDAY AND SUNDAY AFTERNOON.
THE UPPER LEVEL RIDGE ACROSS THE WESTERN UNITED STATES WILL THEN
SHIFT EASTWARD INTO THE ROCKIES AND PLAINS DURING THE FIRST PART OF
NEXT WEEK. THIS FEATURE IN CONJUNCTION WITH SURFACE HIGH PRESSURE
LOCATED EAST OF KANSAS WILL BRING MOSTLY CLEAR SKIES AND DRY
CONDITIONS TO WESTERN KANSAS. LEE TROUGHING ACROSS EASTERN COLORADO
WILL CONTINUE AND BRING WARM TEMPERATURES TO THE AREA. HIGHS MONDAY
ARE FORECASTED TO REACH INTO THE 80S WITH HIGHS AROUND 90 DEGREES ON
TUESDAY. LOWS WILL GENERALLY BE IN THE 50S MONDAY AND TUESDAY
MORNING.
MID RANGE MODELS THEN SUGGEST THE UPPER LEVEL LOW ACROSS NORTHERN
MEXICO TO MOVE BACK NORTHEAST TO THE SOUTHERN PLAINS. THIS WOULD
BRING INCREASING CHANCES OF THUNDERSTORMS TO PARTS OF KANSAS MID
WEEK INTO THE FIRST PART OF THE WEEKEND. HIGHS DURING THIS TIME
FRAME WILL GENERALLY BE IN THE 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1212 AM CDT FRI MAY 10 2013
A LONG TROUGH OF UPPER LEVEL LOW PRESSURE STRETCHED FROM NORTHEAST
TO SOUTHWEST ACROSS WESTERN KANSAS THIS MORNING. SOME
STRATOCUMULUS CLOUDS HAVE ADVECTED INTO THE KHYS TAF SITE, AND
CIGS THERE SHOULD STAY IN THE MVFR CATEGORY AROUND OVC025 THROUGH
10Z OR SO. AFTER 10Z, EXPECT MVFR CIGS AT ALL THREE TAF SITES, IN
THE BKN-OVC035-040 RANGE. WHEN WINDS SHIFT MORE TO THE NORTHEAST
LATER THIS AFTERNOON, CLOUDS SHOULD SCATTER OUT IN THE 060-070
FOOT RANGE. CLOUDS WILL DECREASE EVEN MORE TOWARD SUNSET, AND
WINDS WILL AGAIN BECOME LIGHT AND VARIABLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 71 45 73 / 10 20 10 10
GCK 47 70 46 75 / 10 20 10 10
EHA 47 71 49 78 / 10 20 10 10
LBL 48 73 48 78 / 10 20 10 10
HYS 48 68 43 69 / 20 20 20 20
P28 50 73 48 70 / 10 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...HOVORKA_42
AVIATION...BURKE
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW ORLEANS LA
339 AM CDT FRI MAY 10 2013
.SHORT TERM...
QUITE ACTIVE MORNING IN STORE FOR ALL OF SOUTHEAST LOUISIANA AND
SOUTHERN MISSISSIPPI. A MCS THAT ORIGINATED IN NORTH CENTRAL TEXAS
HAS BECOME ORGANIZED AND IS CURRENTLY MARCHING ACROSS CENTRAL AND
SOUTHWEST LOUISIANA TOWARDS OUR CWA. STARTING UP TOP...DIFFLUENCE
ALOFT WILL AIDE IN THE COMPLEX MAINTAINING ITS INTENSITY AS IT
TRACKS EASTWARD. CAPE VALUES FOR OVERNIGHT PERIOD STILL QUITE
SUFFICIENT AT AROUND 1500 J/KG. MOISTURE IS NO ISSUE OF LIMITATION
EITHER AS LATEST SOUNDING SHOWED PLENTY THROUGHOUT THE COLUMN AND
SFC DEWPOINTS ARE WELL INTO THE 60S TO AROUND 70 AT THE COAST.
STEEP MID LEVEL LAPSE RATES WILL BE CONDUCIVE FOR SMALL HAIL AND
THUS VERY FREQUENT LIGHTNING. THIS ALONG WITH EMBEDDED VORTICIES
AND BOWING SEGMENTS CAN BE EXPECTED ALONG THIS LINE AS IT MOVES
THROUGH. SO ALL MODES OF SEVERE WEATHER POSSIBLE WITH DAMAGING
WINDS THE GREATEST THREAT THRU PRECIP LOADING. SEVERE THUNDERSTORM
WATCH NOW IN EFFECT UNTIL 10 AM FOR THIS THREAT. MEDIUM RANGE
MODELS PERFORMING FAIRLY POORLY WITH THIS MESO FEATURE.
GFS/ECMWF/SREF/NAM ALL SHOW IT MUCH FURTHER NORTH THAN IT ACTUALLY
IS. OF A FEW MESO MODELS...THE HRRR HAS INITIALIZED THE BEST AND
HAS BEEN DOING QUITE WELL OVER THE LAST FEW HOURS SO HAVE MOST
CONFIDENCE IN IT. THIS MODEL SHOWS THE LINE OF STORMS REMAINING
INTACT THROUGH MID MORNING(9-10AM). BY THIS TIME IT SHOULD BE
REACHING THE MISSISSIPPI COAST AND INTO THE NEW ORLEANS METRO
AREA. AS THE LINE PROGRESSES EASTWARD FROM THIS POINT...IT APPEARS
IT WILL BE MOVING INTO A LESS FAVORABLE ENVIRONMENT WITH MUCH LESS
INSTABILITY AND AND WEAKER MID LEVEL WINDS.
NOW...AFTER THIS FEATURE SWINGS THROUGH...THE REST OF THE AFTERNOON
WITH NOT BE TOO QUIET THOUGH SEVERE POTENTIAL LOOKS TO BE MUCH
LOWER. MESO MODELS SHOW A WIDESPREAD SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS THE CWA AFTER MAYBE A FEW HOURS OF DOWNTIME.
THINKING THAT THE MAIN THREAT WILL BE FLASH FLOODING. WITH AN INCH
OR 2 POSSIBLE WITH THIS MORNING/S MCS AND MORE IN THE AFTERNOON...
IT WILL NOT TAKE MUCH FOR STREETS TO FLOOD AS MUCH OF THE AREA HAS
BEEN GETTING POUNDED WITH RAIN FOR AWHILE NOW. NOT TO MENTION THAT
MODEL SOUNDINGS SHOW PRECIP WATER VALUES 1.5 TO 2 INCHES WHICH WILL
RESULT IN EFFICIENT RAIN PRODUCING THUNDERSTORMS. FLASH FLOOD WATCH
REMAINS IN EFFECT AND WARNINGS POSSIBLE THROUGHOUT THE DAY.
RELIEF DOESN/T COME UNTIL SOMETIME OVERNIGHT AND HOW MUCH DEPENDS ON
HOW LONG IT TAKES FOR NEXT IMPULSE TO REACH THE COAST. A VORTMAX
RUNNING NORTHEASTWARD ALONG THE SLOW MOVING FRONTAL BOUNDARY WILL
ENHANCE SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE CWA FROM SW TO
NORTHEAST. THE POSITION OF THE FRONT IS FAIRLY CRITICAL TOO AS IT
WILL BE THE MAIN FOCUS FOR CONVECTION. GFS SUGGESTS IT WILL BE
FURTHER SOUTH ALONG THE LA COAST BY SAT 18Z. ECMWF AND SREF SAY
50-100 MILES FURTHER NORTH. FOR NOW THE FORECAST IS BASED ON THE
NORTHERN POSITION SO HAVE A HIGHER POP FORECAST THAT MAV/MEX. HEAVY
RAIN/TRAINING WILL CONTINUE WHEREVER MOST OF THE RAIN FALLS.
RAIN CHANCES WILL SIGNIFICANTLY FALL OFF SATURDAY NIGHT AND SUNDAY
AS SECONDARY FRONT FROM DEEPER UPPER LEVEL TROUGH SWINGS THROUGH.
HAVE TRIMMED POPS OFF ALL AREAS NORTH OF NEW ORLEANS METRO LATITUDE
BY SUNDAY. SLIGHTLY BELOW NORMAL TEMPS CAN BE EXPECTED THOUGH NOT BY
MUCH AS COMBINATION OF CLEAR SKIES AND HIGH ENOUGH SUN ANGLE WILL
KEEP HIGHS AROUND 80S.
MEFFER
.LONG TERM...
FAIRLY BENIGN WEATHER EXPECTED FOR MUCH OF NEXT WEEK. DEEP UPPER
TROUGH WILL BE MOVING ACROSS THE EASTERN CONUS ON MONDAY AND THEN
EXITING INTO THE ATLANTIC ON TUESDAY. BY THEN...STRONG UPPER RIDGING
WILL BE BUILDING INTO THE GULF COAST REGION. SO EXPECT THOSE TEMPS
TO QUICKLY RESPOND AND BOUNCE RIGHT BACK TO CLIMATOLOGICAL NORMALS.
RAIN CHANCES NIL TO LOW ALL WEEK.
MEFFER
&&
.MARINE...HIGH PRESSURE IS SLIDING EAST AND THIS IS TIGHTENING THE
PRESSURE GRADIENT OVER THE REGION. WINDS OF 15 TO 20 KTS ARE
OCCURRING OVER MUCH OF THE OPEN WATERS ALREADY AND WILL CONTINUE
THROUGH MUCH OF THE DAY UNTIL THE FRONT LAYS UP OVER THE CWA THIS
AFTN. THIS WILL LEAD TO A WEAKENING OF THE GRADIENT AND THUS WINDS
WILL BACK OFF. THE FRONT WILL SLOWLY SINK SOUTH TONIGHT AND THROUGH
THE WEEKEND AND FINALLY PUSH INTO THE GULF SUN NIGHT. HIGH PRESSURE
WILL QUICKLY BUILD IN BEHIND THE FRONT WITH MODERATE TO STRONG
OFFSHORE WINDS DEVELOPING OVER MOST OF THE OPEN WATERS SUN NIGHT.
HIGH PRESSURE WILL SLOWLY TAKE CONTROL OF THE SERN CONUS WITH WINDS
SLACKING OFF MON NIGHT AND TUE BUT BY TUE NIGHT AND INTO THE MIDDLE
OF NEXT WEEK MODERATE ONSHORE WILL REDEVELOP AS THE SFC HIGH PUSHES
OFF THE FL/GA COAST INTO THE WRN ATLANTIC. /CAB/
&&
.AVIATION...MOST TERMINALS ARE MAINLY DEALING WITH MVFR CIGS BUT
CONDITIONS WILL DETERIORATE THROUGH THE MORNING HAS A LINE OF SHRA
AND TSRA MOVES THROUGH THE AREA. BTR AND MCB WILL BE IMPACTED FIRST
AROUND 9-11Z FOLLOWED BY HDC/HUM/MSY/NEW/ASD B/T 12-14Z. CIGS AND
VISBIES WILL BOTH LOWER WITH THE CONVECTION AND GUSTS COULD APPROACH
40-50KTS WITH THE STRONGEST STORMS. THERE IS EVEN THE THREAT OF GR
BUT THE MAIN CONCERN IS WIND. EVEN AFTER THE MAIN LINE MOVES THROUGH
THERE WILL LIKELY BE SHRA AND EMBEDDED TSRA OVER THE REGION
THROUGHOUT THE DAY AND MAYBE EVEN INTO THE OVERNIGHT HRS. /CAB/
&&
.DECISION SUPPORT...
DSS CODE...YELLOW.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
MONITORING RIVERS
SEVERE THUNDERSTORM WATCH IN EFFECT
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 80 65 78 57 / 100 60 70 10
BTR 82 68 80 61 / 100 60 70 20
ASD 79 68 80 61 / 100 50 80 20
MSY 81 70 80 64 / 90 40 80 20
GPT 78 69 78 62 / 90 50 80 20
PQL 78 69 80 60 / 70 40 80 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 1 AM SUNDAY FOR THE
FOLLOWING ZONES: ASCENSION...ASSUMPTION...EAST BATON
ROUGE...EAST FELICIANA...IBERVILLE...LIVINGSTON...NORTHERN
TANGIPAHOA...ORLEANS...POINTE COUPEE...SOUTHERN
TANGIPAHOA...ST. CHARLES...ST. HELENA...ST. JAMES...ST.
JOHN THE BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER
LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER
TERREBONNE...WASHINGTON...WEST BATON ROUGE...AND WEST
FELICIANA.
GM...NONE.
MS...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 1 AM SUNDAY FOR THE
FOLLOWING ZONES:
AMITE...HANCOCK...HARRISON...JACKSON...PEARL
RIVER...PIKE...WALTHALL...AND WILKINSON.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1256 AM CDT FRI MAY 10 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
A FEW LIGHT SHOWERS WILL CONTINUE TO WRAP AROUND THE
SURFACE LOW ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY THROUGH THE
LATE AFTERNOON HOURS...AS IT CONTINUES TO TRANSITION FURTHER
EASTWARD. STILL CANNOT RULE OUT THE SLIGHT POSSIBILITY OF A
THUNDERSTORM OR TWO...MAINLY ACROSS PORTIONS OF NORTH CENTRAL
KANSAS...AS MESO ANALYSIS PAGE FROM SPC IS INDICATION SOME WEAK
INSTABILITY PERSISTING ACROSS THIS AREA. LATEST WRF ACTUALLY
HANGS ONTO SOME SCATTERED SHOWER ACTIVITY THROUGH THE OVERNIGHT
HOURS...BUT THIS MODEL SEEMS TO BE THE OUTLIER...SO HAVE NO MORE
THAN A FEW SPRINKLES IN THE FORECAST AFTER 00Z.
THEREAFTER...EXPECT A SURFACE RIDGE OF HIGH PRESSURE TO SLIDE
ACROSS THE FORECAST AREA FROM THE WEST OVERNIGHT...AND WITH THE
ANTICIPATED LIGHT WINDS...PARTIAL CLEARING...AND ELEVATED DEW
POINTS...EXPECT SOME FOG DEVELOPMENT OVERNIGHT. LATEST HRRR IS
HINTING AT DENSE FOG FORMING ALONG THE SPINE OF THE RIDGE AXIS
AFTER MIDNIGHT...BUT WITH SOME UNCERTAINTY STILL...ONLY REDUCED
VISIBILITIES TO 1 MILE ACROSS THE FORECAST AREA DURING THE LATE
OVERNIGHT HOURS THROUGH EARLY FRIDAY MORNING...AND HELD OFF ON
ISSUING A DENSE FOG ADVISORY FOR THE TIME BEING.
AFTER THE FOG BURNS OFF FRIDAY MORNING...EXPECT A FAIRLY NICE AND
SEASONAL DAY ACROSS THE REGION...AS THE SURFACE RIDGE WILL BE SLOW
TO PUSH EAST RESULTING IN GENERALLY LIGHT WINDS DURING THE
AFTERNOON HOURS. WITH CLEARING SKIES...RECOVERING TEMPERATURES
ALOFT...AND GOOD MIXING ANTICIPATED...EXPECT TEMPERATURES TO
RETURN TO NEAR CLIMATOLOGICAL NORMS...GENERALLY IN THE LOWER 70S
AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
REALLY NO SIGNIFICANT CHANGES FOR THE FIRST PORTION OF THE LONG TERM
PERIOD...FRIDAY NIGHT THROUGH THE DAY SATURDAY. MODELS REMAIN IN
PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN...SHOWING FRIDAY
EVENING UNDER SHARP NORTHWESTERLY FLOW...A RESULT OF A TROUGH AXIS
PUSHING EAST OF THE CWA...AND RIDGING POKING INTO THE CENTRAL/NRN
WEST COAST...NORTH OF CUT OFF LOW OVER THE NM/AZ/MEX BORDER AREA.
FOCUS TURNS TO AN UPPER LEVEL LOW PRESSURE SYSTEM OVER CENTRAL
CANADA...WHICH IS EXPECTED TO SLIDE SOUTHEAST OVERNIGHT AND BY
SATURDAY MORNING IS REACHING INTO THE WRN GREAT LAKES AREA. THE
ACCOMPANYING TROUGH AXIS WILL EXTEND TO THE SOUTH AND SWING THROUGH
THE CENTRAL PLAINS PRIMARILY FRIDAY NIGHT...AND KEPT THE MENTION OF
SPRINKLES GOING ACROSS THE NRN HALF OF THE CWA. WITH THE BRUNT OF
THE LIFT WELL NE OF THE CWA...AND FORECAST SOUNDINGS CONTINUING TO
SHOW DRIER AIR IN THE AREA...DIDNT WANT TO INSERT ANY MEASURABLE
PRECIP AT THIS POINT. THE TIMING OF THE SFC COLD FRONT PUSHED
THROUGH THE CWA BY THIS DISTURBANCE HASNT CHANGED MUCH WITH THE
LATEST MODEL RUNS...AND BY 12Z SATURDAY LOOKS TO HAVE PUSHED THROUGH
TO AT LEAST THE NE/KS STATE LINE...AND EVEN A LITTLE FURTHER SOUTH
VIA THE NAM/SREF. THROUGH THE DAYTIME HOURS ON SATURDAY...SHOULD
SEE DECREASING CLOUD COVER...AND EXPECTING WINDS TO BE ON THE GUSTY
SIDE THROUGH AT LEAST THE FIRST HALF OF THE DAY...BUT SHOULD
DIMINISH ESP BY LATE AFTERNOON AS SFC HIGH PRESSURE BUILDS IN FROM
THE NORTH. THE COOLER AIRMASS ACCOMPANYING THIS FRONT IS EXPECTED
TO BRING A DROP IN HIGHS...BUT STILL EXPECTING TO REACH INTO THE
60S.
FOR SATURDAY NIGHT AND SUNDAY...MAIN CHANGE MADE TO THIS TIME FRAME
WAS TO ADD POPS TO THE FORECAST. YESTERDAY THERE WAS JUST A HINT AT
THE POSSIBILITY OF THE ACTIVITY DEVELOPING ALONG THE HIGH PLAINS
/DRIVEN BY UPSLOPE FLOW AND A WEAK MID LEVEL DISTURBANCE/ SATURDAY
AFTERNOON SLIDING SOUTHEAST AND AFFECTING AT LEAST PORTIONS OF THE
CWA...BUT NOW THE 12Z RUNS OF THE OPERATIONAL MODELS HAVE TRENDED
THIS WAY. ADDED SOME SLIGHT CHANCE AND CHANCE POPS FOR NOW...STILL
SOME SLIGHT VARIATIONS WITH TIMING/LOCATIONS...BUT MOST DO SHOW
ACTIVITY LINGERING INTO THE 12-18Z PERIOD SUNDAY. INSTABILITY IS
PRETTY PATHETIC...MUCAPE VALUES OF ARND 100 J/KG...SO WHILE AN
ISOLATED RUMBLE OF THUNDER OR TWO ARE POSSIBLE...NOT EXPECTING
WIDESPREAD THUNDERSTORMS. DEPENDING ON THE SPEED THIS ACTIVITY
EXISTS...THE HIGHS FOR THE DAY MAY NEED SOME ADJUSTMENT. TRENDED
HIGHS BACK JUST A DEGREE OR TWO OVERALL...BUT IF THINGS LINGER
LONGER THAN CURRENTLY EXPECTED...TEMPS WILL LIKELY STRUGGLE TO REACH
WHAT IS FORECAST /MID 60S TO NEAR 70/.
MONDAY AND TUESDAY...HERE COMES THE WARM UP. PAST FEW RUNS OF THE
MODELS HAVE BEEN PRETTY CONSISTENT WITH THE PATTERN ACROSS THE
CONUS...AT 12Z MONDAY THE CWA IS STILL SITTING UNDER NORTHWESTERLY
FLOW...AS THE CUT OFF LOW CONTINUES TO SIT OVER NRN MEX...AND
RIDGING ORIGINATING OFF THE WEST COAST IS EXTENDED INTO THE
ROCKIES. BY THE END OF THE DAYTIME HRS ON MONDAY AXIS LOOKS TO HAVE
SHIFTED FURTHER EAST INTO THE ROCKIES. WARMER AIR ACCOMPANYING THIS
RIDGE WILL BRING A BUMP UP IN TEMPS MONDAY...AND AGAIN TUESDAY AS
THE CWA REMAINS UNDER ITS INFLUENCE. HIGHS ON MONDAY CURRENTLY
FORECAST TO REACH THE UPPER 70S TO MID 80S...WITH TUESDAY LOOKING AT
MID 80S TO NEAR 90 DEGREES.
A LITTLE MORE UNCERTAINTY IN THE FORECAST ARISES FOR WEDNESDAY AND
THURSDAY...WITH THE POTENTIAL FOR PRECIP RETURNING. THE UPPER LEVEL
RIDGE LOOKS TO BECOME BROKEN DOWN...FROM BOTH THE LOW WHICH HAD BEEN
SET UP OVER MEX SHIFTING EAST INTO THE PLAINS...AND ADDITIONAL
ENERGY SLIDING IN FROM THE PAC NW. PLENTY OF THINGS TO IRON OUT IN
THE COMING DAYS...BUT AT THIS POINT KEPT POPS CONFINED TO THE
WED/THURS DAYTIME PERIOD...HOWEVER HAVE NO DOUBT THE TIMING WILL BE
ADJUSTED. THESE DISTURBANCES LOOK TO BRING THE POTENTIAL FOR SFC
FRONTS MOVING INTO THE AREA...WITH A SLIGHT DECREASE IN TEMPS...WITH
HIGHS BOTH DAYS CURRENTLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1239 AM CDT FRI MAY 10 2013
THE PRIMARY AVIATION CONCERN WILL CONTINUE TO CENTER AROUND THE
POSSIBILITY OF FOG AS WE NEAR DAWN. AM STILL SEEING THE POTENTIAL
FOR FOG IN FORECAST MODELS...INCLUDING THE HRRR. THEREFORE...WILL
CONTINUE WITH THE LOW CEILING HEIGHTS AND REDUCED VISIBILITIES
FROM THE 00Z TAF...BUT HAVE DELAYED THE ONSET OF THE FOG BY 1 HOUR
BASED ON LATEST MODEL RUNS. THE WIND WILL CONTINUE TO BE LIGHT
THROUGHOUT THE TAF PERIOD AND GENERALLY FROM THE NORTH TODAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
438 AM EDT FRI MAY 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS OUR AREA TODAY BRINGING MORE RAIN
SHOWERS AND POSSIBLE THUNDERSTORMS. IN THE WAKE OF THIS STORM
SYSTEM...PROGRESSIVELY COOLER AIR WILL FLOOD ACROSS THE REGION THIS
WEEKEND...WITH TEMPERATURES FALLING BACK TO WELL BELOW NORMAL LEVELS
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID-LEVEL RIDGE CENTERED OVER NEW YORK EARLY THIS MORNING. SATELLITE
IMAGERY IS SHOWING LAYER OF HIGH CLOUDS SHIFTING ACROSS WESTERN
COUNTIES OUT AHEAD OF A STORM SYSTEM OVER OHIO WITH SOME LOW CLOUDS
AND FOG FOUND EAST OF LAKE ONTARIO. WITHIN THESE LOWER CLOUDS...
KTYX RADAR IS SHOWING A FEW SHOWERS DRIFTING SOUTHEAST ACROSS
NORTHERN NEW YORK WHICH ARE THE LAST REMNANTS OF THE STORM SYSTEM
WHICH BROUGHT RAIN YESTERDAY. THE CURRENT SHOWERS ARE VERIFYING THE
LATEST HRRR MODEL RUN SO HAVE CONTINUED TO FEATURE A CHANCE FOR
SHOWERS ACROSS EASTERN LAKE ONTARIO COUNTIES THROUGH THE EARLY
MORNING. IN ADDITION TO THE SHOWERS SOME FOG IS BEING REPORTED AT
KFZY AND KART SO WILL CONTINUE TO INCLUDE PATCHY FOG IN THIS
MORNINGS FORECAST. TEMPERATURES ARE RUNNING A LITTLE ABOVE
NORMAL...WITH EARLY MORNING LOWS EXPECTED TO RANGE FROM THE MID
AND UPPER 40S IN THE COOLER SOUTHERN TIER VALLEYS TO THE MID 50S ACROSS
PARTS OF THE FINGER LAKES AND LAKE PLAINS.
RAIN SHOWERS ARE IN THE FORECAST FOR TODAY WITH A CHANCE FOR SOME
THUNDER AS A STORM SYSTEM TO OUR WEST WILL SHIFT EAST ACROSS OUR
REGION DURING THE COURSE OF THE DAY. THE CENTER OF THE SURFACE LOW IS
LOCATED NEAR SOUTHERN LAKE MICHIGAN AND WILL TRACK TO THE
EAST-NORTHEAST ACROSS LAKE ERIE THIS AFTERNOON THEN RUNNING JUST
NORTH OF LAKE ONTARIO TONIGHT. CURRENT GREAT LAKES REGIONAL RADAR
MOSAIC SHOWING LEADING BAND OF THUNDERSTORMS OVER OHIO WITH RAIN
SHOWERS SPREAD TO THE NORTH AND WEST BACK TOWARD THE CENTER OF THE
LOW.
MODEL GUIDANCE INCLUDING LATEST HRRR SHOWS RAIN SHOWERS WILL
ARRIVE ACROSS THE SOUTHERN TIER BETWEEN 12-14Z THE NIAGARA FRONTIER
14-17Z AND THEN ROCHESTER ON EASTWARD THROUGH THE AFTERNOON HOURS.
NOT EXPECTING THE CURRENT THUNDERSTORMS OVER OHIO TO REACH INTO OUR
FORECAST AREA THIS MORNING. THE HRRR MODEL SHOWS THESE WILL STAY
JUST TO THE SOUTH ACROSS PA. LATER THIS AFTERNOON THE NAM MODEL
SHOWS SOME WEAK INSTABILITY WITH MLCAPES OF UP TO 500 J/KG...HAVE
LEFT CHANCE FOR THUNDERSTORMS IN THE FORECAST. ADDITIONAL FORCING FOR
TODAYS WEATHER IS PROVIDED BY 30-40 KNOT LOW LEVEL JET WHICH MAY MIX
DOWN SOME TOWARD THE SURFACE DURING THE DAY BRINGING SOME WIND GUSTS
TO 20-30 MPH RANGE.
DURING THE AFTERNOON HOURS SOME AREAS COULD SEE A BREAK IN SHOWER
ACTIVITY BEFORE A COLD FRONT BRINGS ADDITIONAL RAIN SHOWERS LATER
THIS EVENING. THE COLD FRONT WILL LIKELY CROSS THE FORECAST AREA
BETWEEN MIDNIGHT AND EARLY MORNING WITH CHANCES FOR RAIN SHOWERS
RAPIDLY LOWERING ON ITS HEELS. RAINFALL AMOUNTS WILL RUN BETWEEN A
HALF AND ONE INCH USING BLEND OF SREF AND WPC GUIDANCE WHICH SEEMS
REASONABLE WITH MOIST GREATER THAN ONE INCH PWAT AIRMASS SHIFTING
OVER THE FORECAST AREA AHEAD OF THE SURFACE LOW. ANOTHER DAY OF MILD
TEMPERATURES BUT READING WILL BE CLOSER TO NORMAL. HIGHS WILL RUN IN
THE UPPER 60S TO LOW 70S. LOWS TONIGHT WILL FALL INTO THE UPPER 40S
ACROSS WNY BUT MAY REMAIN IN THE MID 50S OR SO ACROSS CNY AS COLD
FRONT ARRIVES LATER IN THE NIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE SURFACE LOW RESPONSIBLE FOR FRIDAY AND FRIDAY NIGHT/S RAINFALL
WILL BE LIFTING OUT OF THE REGION AND DOWN THE SAINT LAWRENCE VALLEY
ON SATURDAY. THE DEEPEST MOISTURE AND HEAVIEST SHOWERS ASSOCIATED WITH
THIS SYSTEM SHOULD BE PUSHING OUT OF THE NORTH COUNTRY SATURDAY
MORNING...HOWEVER SCATTERED SHOWERS ARE EXPECTED LINGER THROUGH THE
MORNING HOURS ACROSS MUCH OF THE FORECAST AREA AS AN UPPER LEVEL
VORTMAX TRACKS ACROSS WESTERN AND UPSTATE NEW YORK. EXPECT SHOWERS
TO TAPER OFF FROM WEST TO EAST BY THE AFTERNOON AS COOLER AND DRIER
AIR MAKES ITS WAY INTO THE LOWER GREAT LAKES. LOOK FOR TEMEPRATURES
TO DROP BACK BELOW NORMAL AS THIS COOLER AIR FILTERS INTO THE REGION
WITH HIGHS IN THE UPPER 50S TO LOWER 60S...THOUGH TYPICALLY WARMER
SPOTS IN THE GENESEE VALLEY AND FINGER LAKES SHOULD MANAGE TO REACH
THE MID 60S.
LOOK FOR A MUCH MORE SIGNIFICANT DROP IN TEMEPETAURES TO OCCUR
SATURDAY NIGHT AS A POTENT UPPER LEVEL LOW DROPS INTO THE GREAT
LAKES FROM WESTERN ONTARIO...PUSHING A SHARP COLD FRONT ACROSS THE
LOWER GREAT LAKES AHEAD OF IT. EXPECT TERMERPATURES TO DROP INTO THE
UPPER 30S ACROSS WESTERN NEW YORK AND THE SOUITHERN TIER SATURDAY
NIGHT AS MUCH COLDER AND DRIER AIR ADVECTS INTO THE EMPIRE STATE.
ONSHORE FLOW AND A LATER TIMING OF THE FRONTAL PASSAGE OVERNIGHT
SHOULD KEEP THE NORTH COUNTRY AND AREAS NEAR LAKE ONTARIO IN THE
40S. LIMITED MOISTURE MEANS THAT ANY SHOWER ACTVITY
ACCOMPANYING THE FRONTAL PASSAGE SHOULD BE LIMITED TO JUST A FEW
LIGHT SHOWERS AT BEST.
SUNDAY WILL BE COLD AND BLUSTERY AS THE AFORMENTIONED UPPER LEVEL
TRACKS INTO QUEBEC WHILE THE UPPER LEVEL TROUGH AXIS SWINGS ACROSS
THE LOWER GREAT LAKES. WELL ALIGNED WESTERLY FLOW COUPLED WITH
FAIRLY STEEP LOW LEVEL LAPSE RATES THANKS TO THE STRONG COLD
ADVECTION ALOFT WILL ALLOW FOR GOOD MIXING IN THE BOUNDARY
LAYER...RESULTING IN GUSTS OF 25 TO 40 MPH ACROSS MCUH OF THE
FORECAST AREA...PARTICULARLY DOWNWIND OF THE LAKES WHERE GALE FORCE
GUSTS WILL BE POSSIBLE. THE WINDY CONDITIONS WILL SERVE TO FURTHER
EMPHASIZE THE CHILL AS HIGHS ARE ONLY EXPECTED TO REACH THE UPPER
40S TO LOWER 50S WITH WIND CHILLS IN THE 30S. IN ADDITION THE
INSTABILITY INDUCED BY THE COLD ADVECTION ALOFT WILL YIELD PLENTY OF
CLOUD COVER ACROSS THE AREA ALONG WITH A POTENTIAL FOR SCATTERED
RAIN SHOWERS IN THE AFTERNOON.
THE CHILL WILL CONTINUE INTO SUNDAY NIGHT AS THE UPPER LEVEL TROUGH
AND THE CORE OF THE COLD AIR ALOFT CROSSES NEW YORK STATE AS 850MB
TEMPS DROP BELOW -6C. OVERNIGHT LOWS NEAR THE LAKES WILL DROP INTO
THE MID 30S WHILE FARTHER INLAND A HARD FREEZE WILL BE POSSIBLE
ACROSS THE SOUTHERN TIER AS LOWS BOTTOM OUT IN THE UPPER 20S. THE
COMBINATION OF CONTINUED WESTERLY FLOW ACROSS THE LAKES ALONG WITH
THE COLD AIR ALOFT COULD GENERATE LAKE EFFECT
PRECIPITATION...PARTICULARLY EAST OF LAKE ONTARIO WHERE SFC-850MB
DELTA-T VALUES WILL DROP TO -14C. HAVE BUMPED POPS UP TO LIKELY
ACROSS THE NORTH COUTNRY AND GIVEN THAT TEMPS WILL DROP INTO THE MID
30S THERE...WE COULD SEE A RAIN/SNOW MIX ACROSS THE TUG HILL PLATEAU.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE RETURN TO MORE ACTIVE WEATHER WILL CONTINUE THROUGH THE LONG
TERM NOW THAT THE PERSISTENT BLOCKING PATTERN HAS BEEN BROKEN
DOWN...TO BE REPLACED BY A MORE ZONAL FLOW ALONG THE US/CANADIAN
BORDER.
THE UPPER LEVEL TROUGH THAT BROUGHT THE COOL DOWN OVER THE WEEKEND
WILL CONTINUE TO IMPACT THE REGION MONDAY. AS A RESULT HIGHS ON
MONDAY WILL ONLY BE IN THE LOWER TO MID 50S AT BEST...WITH UPPER 40S
ACROSS HIGHER TERRAIN. TEMPS WILL GET COLD ENOUGH MONDAY NIGHT TO
BRING THE POTENTIAL FOR FROST INLAND FROM THE IMMEDIATE LAKESHORES.
THE TROUGH WILL QUICKLY PULL AWAY MONDAY NIGHT AND TUESDAY MORNING
WITH A RETURN TO DRY WEATHER. A WARM FRONT WILL THEN CROSS THE
REGION ON TUESDAY. MODEL GUIDANCE HAS BEEN WAVERING BETWEEN A MAINLY
DRY WARM FRONT OR BETTER SHOWER CHANCES. FOR NOW WILL STICK WITH
PREVIOUS FORECAST CONTINUITY AND KEEP TUESDAY MAINLY DRY.
FROM WEDNESDAY INTO THURSDAY A MUCH WARMER AIRMASS WILL PUSH QUICKLY
EAST ACROSS THE NATION AND INTO OUR REGION AS THE PATTERN REMAINS
PROGRESSIVE AND BEGINS TO DE-AMPLIFY. EXPECT TEMPS TO SOAR TO WELL
ABOVE AVERAGE AGAIN. UNLIKE THE LAST WARM STRETCH...A FRONTAL ZONE
AND MORE ACTIVE FLOW ALOFT WILL BE NEARBY. THIS WILL BRING CHANCES
OF SHOWERS AND EVEN A FEW THUNDERSTORMS TO THE REGION ALONG WITH A
SOMEWHAT MUGGIER AIRMASS.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS ALL OF WESTERN NEW YORK THIS
MORNING BUT EAST OF LAKE ONTARIO SOME MVFR/IFR IS BEING REPORTED AT
KFZY AND KART. THIS WILL CONTINUE THROUGH THE MORNING HOURS BREAKING
UP AFTER SUNRISE.
LATER TODAY...ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE
OHIO VALLEY WITH THICKENING CLOUDS AND RAIN SHOWERS ARRIVING ACROSS
THE REGION FROM SOUTHWEST TO NORTHEAST. UPDATED TAFS WITH LATEST
HRRR GUIDANCE FOR START TIME OF -SHRA. A CHANCE OF A FEW
THUNDERSTORMS MAY ALSO BECOME POSSIBLE AS SOME WEAK TO MODEST
INSTABILITY REDEVELOPS IN THE AFTERNOON BUT HAVE LEFT OUT OF THE
TAFS DUE TO LOWER CONFIDENCE AT ANY PARTICULAR SITE. TERMINALS WILL
LOWER BACK TO MVFR/IFR LATER THIS EVENING WHEN THE SYSTEMS COLD FRONT
SHIFTS TOWARD WNY WITH BETTER COVERAGE OF RAIN SHOWERS AND LOWER CIGS.
OUTLOOK...
SATURDAY...SHOWERS TAPERING OFF WITH IMPROVEMENT BACK TO MVFR/VFR.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS
BOTH DAYS.
TUESDAY...VFR.
&&
.MARINE...
A BRIEF PERIOD OF QUIETER AND DRIER WEATHER CAN BE EXPECTED
OVERNIGHT...BEFORE ANOTHER LOW PRESSURE SYSTEM PUSHES EAST FROM THE
CENTRAL GREAT LAKES LATER THIS MORNING AND BRINGS A RETURN OF MORE
SHOWERS AND POSSIBLE THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...THE PRESSURE GRADIENT ACROSS THE LOWER
LAKES WILL REMAIN WEAK OVERNIGHT...BEFORE TIGHTENING A LITTLE LATER
TODAY. COUPLED WITH STABLE TEMPERATURE PROFILES...THIS WILL RESULT IN A
CONTINUATION OF RELATIVELY LIGHT WINDS AND MINIMAL WAVES
TONIGHT...BEFORE THESE INCREASE SOMEWHAT ON LAKE ONTARIO. THE ABOVE
SAID...THESE SHOULD STILL REMAIN BELOW ADVISORY CRITERIA.
BEHIND THE SECOND LOW...A PROGRESSIVELY STRONGER WESTERLY FLOW WILL
SET UP ACROSS THE LOWER LAKES REGION OVER THE WEEKEND...WITH WINDS
AND WAVES POSSIBLY INCREASING TO ADVISORY LEVELS BY SUNDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...HITCHCOCK/WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
214 AM EDT FRI MAY 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS OUR AREA TODAY BRINGING MORE RAIN
SHOWERS AND POSSIBLE THUNDERSTORMS. IN THE WAKE OF THIS STORM
SYSTEM...PROGRESSIVELY COOLER AIR WILL FLOOD ACROSS THE REGION THIS
WEEKEND...WITH TEMPERATURES FALLING BACK TO WELL BELOW NORMAL LEVELS
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MID-LEVEL RIDGE IS SHIFTING OVER NEW YORK EARLY THIS MORNING WITH
ITS AXIS CENTERED JUST TO OUR WEST. SATELLITE IMAGERY IS SHOWING
LAYER OF HIGH CLOUDS SHIFTING ACROSS WESTERN COUNTIES OUT AHEAD OF A
STORM SYSTEM OVER WESTERN OHIO WITH SOME LOW CLOUDS EAST OF LAKE ONTARIO.
WITHIN THESE LOWER CLOUDS... KTYX RADAR IS SHOWING A FEW SHOWERS
DRIFTING SOUTHEAST ACROSS NORTHERN NEW YORK WHICH ARE THE LAST
REMNANTS OF THE STORM SYSTEM WHICH BROUGHT RAIN YESTERDAY. THE
CURRENT SHOWERS ARE VERIFYING THE LATEST HRRR MODEL RUN SHOW HAVE
CONTINUED TO FEATURE A CHANCE FOR SHOWERS ACROSS EASTERN LAKE
ONTARIO COUNTIES THROUGH THE EARLY MORNING. IN ADDITION TO THE
SHOWERS SOME FOG IS BEING REPORTED AT KFZY AND KART SO WILL CONTINUE
TO INCLUDE PATCHY FOG IN THIS MORNINGS FORECAST. OVERNIGHT
TEMPERATURES WILL REMAIN A LITTLE ABOVE NORMAL...WITH EARLY MORNING
LOWS RANGING FROM THE MID AND UPPER 40S IN THE COOLER SRN TIER
VALLEYS TO THE MID 50S ACROSS PARTS OF THE FINGER LAKES AND LAKE
PLAINS.
LATER THIS MORNING...THE NEXT PACIFIC-BASED SHORTWAVE TROUGH AND
ASSOCIATED SURFACE LOW OVER THE WESTERN GREAT LAKES HEADS EASTWARD
INTO OUR REGION. INCREASING WARM AIR ADVECTION OUT AHEAD OF THIS LOW
WILL LEAD TO THICKENING CLOUDS AND MORE SHOWERS SPREADING BACK
ACROSS OUR AREA FROM SOUTHWEST TO NORTHEAST...WITH THESE FOCUSING ON
THE NOSE OF SEVERAL 30-40 KT LOW-MID LEVEL JET SEGMENTS THAT WILL
BODILY LIFT NORTHEAST FROM THE OHIO VALLEY. USING THE FASTER GFS
/WHICH TYPICALLY HANDLES THE SPEED OF WARM AIR ADVECTION-DRIVEN
PRECIP THE BEST/ AS A GUIDE FOR TIMING...SOME OF THESE SHOWERS MAY
REACH FAR SOUTHWESTERN NEW YORK AS EARLY AS 12-13Z FRIDAY
MORNING...THE BUFFALO AREA BY 14Z-15Z...AND KROC AND POINTS EASTWARD
BY EARLY FRIDAY AFTERNOON.
GIVEN THE FAIRLY IMPRESSIVE WARM AIR ADVECTION PATTERN AND
INCREASING LARGE-SCALE LIFT COUPLED WITH PWATS INCREASING TO BETWEEN
1 AND 1.5 INCHES...FEEL THAT SHOWERS WILL EVENTUALLY BECOME A NEAR
CERTAINTY WITH TIME ON FRIDAY...THUS WILL INDICATE POPS INCREASING
TO HIGH-END CATEGORICAL LEVELS. LIKEWISE...GIVEN THE OVERALL PATTERN
AND THE DEVELOPMENT OF SOME WEAK TO MODEST INSTABILITY AS SHOWN BY
THE BULK OF THE GUIDANCE...WILL ALSO CONTINUE TO INDICATE THE CHANCE
FOR SOME EMBEDDED THUNDERSTORMS AS WELL.
TEMPERATURE-WISE...HIGHS TODAY WILL AGAIN BE ABOVE AVERAGE WITH
READINGS RANGING FROM THE UPPER 60S TO MID 70S...AND THE WARMEST
TEMPS GENERALLY OVER INTERIOR SECTIONS OF THE GENESEE VALLEY AND
FINGER LAKES.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
FRIDAY NIGHT A SURFACE LOW WILL PASS JUST NORTH OF LAKES ERIE AND
ONTARIO...WITH AN ASSOCIATED STRONG MID LEVEL SHORTWAVE CROSSING THE
REGION BRINGING A PERIOD OF LARGE SCALE ASCENT. A LOW LEVEL JET
SEGMENT WILL ALSO CROSS THE AREA...THE NOSE OF WHICH IS FORECAST TO
MOVE FROM THE SOUTHERN TIER ACROSS THE FINGER LAKES TO THE EASTERN
LAKE ONTARIO REGION OVERNIGHT. THIS WILL ENHANCE LOW LEVEL
CONVERGENCE AND ASCENT...AND SHOULD CORRESPOND TO THE TRACK OF
HEAVIEST RAINFALL. PWAT VALUES WILL INCREASE TO AROUND 1.5 INCHES...
WHICH WILL COMBINE WITH THE QUALITY DYNAMICS TO PRODUCE WIDESPREAD
SHOWERS ACROSS THE REGION. SOME AREAS MAY SEE UP TO AN INCH OF
RAIN...MOST LIKELY FOLLOWING THE PATH OF THE LOW LEVEL JET FROM THE
SOUTHERN TIER INTO CENTRAL NY. THERE IS ENOUGH INSTABILITY TO
SUPPORT A FEW EMBEDDED THUNDERSTORMS AS WELL WITH LOCALLY HIGHER
RAINFALL AMOUNTS.
LATE FRIDAY NIGHT AND SATURDAY THE RAIN WILL TAPER OFF FROM WEST TO
EAST AS THE SURFACE LOW AND ASSOCIATED SHORTWAVE AND LOW LEVEL JET
MOVES EAST INTO NEW ENGLAND. MODEL GUIDANCE STILL SHOWS A GOOD
AMOUNT OF LOW LEVEL MOISTURE LINGERING INTO SATURDAY MORNING WITH
PLENTY OF CLOUD COVER...ALTHOUGH SOME BREAKS SHOULD DEVELOP LATER IN
THE AFTERNOON. 850MB TEMPS ARE STILL ON THE MILD SIDE AT +4C TO +5C
SO THIS SHOULD STILL SUPPORT HIGHS IN THE 60S DESPITE CLOUD COVER.
SATURDAY NIGHT A SHARP TROUGH WILL DIG INTO THE NORTHERN GREAT LAKES
AND FORCE A STRONG COLD FRONT EAST ACROSS OUR REGION. MOST OF THE
DEEP MOISTURE AND LARGE SCALE ASCENT WILL BE GONE...ASSOCIATED WITH
THE FIRST SYSTEM. STILL...GIVEN THE STRENGTH OF THE COLD FRONT
EXPECT A PERIOD OF SCATTERED SHOWERS TO MOVE FROM WEST TO EAST
ACROSS THE AREA OVERNIGHT.
THIS FRONT WILL USHER IN A MUCH COLDER AIRMASS FOR THE REST OF THE
WEEKEND. STEADY COLD AIR ADVECTION ON SUNDAY WILL KEEP HIGHS IN THE
LOWER TO MID 50S ACROSS LOWER ELEVATIONS...AND BARELY 50 ACROSS
HIGHER TERRAIN. THE DAY SHOULD START OFF DRY...BUT COLD AIR ALOFT
COMBINED WITH THE STRONG MID MAY SUN ANGLE WILL PROMOTE CUMULUS AND
STRATOCUMULUS DEVELOPMENT ALONG WITH SCATTERED SHOWERS DURING THE
AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE RETURN TO MORE ACTIVE WEATHER WILL CONTINUE THROUGH THE LONG
TERM NOW THAT THE PERSISTENT BLOCKING PATTERN HAS BEEN BROKEN
DOWN...TO BE REPLACED BY A MORE ZONAL FLOW ALONG THE US/CANADIAN
BORDER.
SUNDAY NIGHT INTO MONDAY A DEEP LONGWAVE TROUGH WILL DIG INTO THE
LOWER LAKES AND NEW ENGLAND. THIS WILL BRING A SHARP...BUT BRIEF
SHOT OF COLD AIR TO THE REGION. HIGHS ON MONDAY WILL ONLY BE IN THE
LOWER TO MID 50S AT BEST...WITH UPPER 40S ACROSS HIGHER TERRAIN.
TEMPS WILL GET COLD ENOUGH BOTH SUNDAY NIGHT AND MONDAY NIGHT TO
BRING THE POTENTIAL FOR FROST INLAND FROM THE IMMEDIATE
LAKESHORES...ALTHOUGH SUNDAY NIGHT CLOUD COVER MAY HELP TO PROTECT
SOME AREAS FROM FROST. HAVE NOT INCLUDED ANY MENTION OF SNOW YET...
BUT IF ANY PRECIP IS STILL IN THE AREA LATE SUNDAY NIGHT AND MONDAY
MORNING A FEW WET FLAKES OR GRAUPEL PELLETS MAY MIX IN.
THE TROUGH WILL QUICKLY PULL AWAY MONDAY NIGHT AND TUESDAY MORNING
WITH A RETURN TO DRY WEATHER. A WARM FRONT WILL THEN CROSS THE
REGION ON TUESDAY. MODEL GUIDANCE HAS BEEN WAVERING BETWEEN A MAINLY
DRY WARM FRONT OR BETTER SHOWER CHANCES. FOR NOW WILL STICK WITH
PREVIOUS FORECAST CONTINUITY AND KEEP TUESDAY MAINLY DRY.
FROM WEDNESDAY INTO THURSDAY A MUCH WARMER AIRMASS WILL PUSH QUICKLY
EAST ACROSS THE NATION AND INTO OUR REGION AS THE PATTERN REMAINS
PROGRESSIVE AND BEGINS TO DE-AMPLIFY. EXPECT TEMPS TO SOAR TO WELL
ABOVE AVERAGE AGAIN. UNLIKE THE LAST WARM STRETCH...A FRONTAL ZONE
AND MORE ACTIVE FLOW ALOFT WILL BE NEARBY. THIS WILL BRING CHANCES
OF SHOWERS AND EVEN A FEW THUNDERSTORMS TO THE REGION ALONG WITH A
SOMEWHAT MUGGIER AIRMASS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS ALL OF WESTERN NEW YORK THIS
MORNING BUT EAST OF LAKE ONTARIO SOME MVFR/IFR IS BEING REPORTED AT
KFZY AND KART. THIS WILL CONTINUE THROUGH THE MORNING HOURS BREAKING
UP AFTER SUNRISE.
LATER TODAY...ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE
OHIO VALLEY WITH THICKENING CLOUDS AND RAIN SHOWERS ARRIVING ACROSS
THE REGION FROM SOUTHWEST TO NORTHEAST. UPDATED TAFS WITH LATEST
HRRR GUIDANCE FOR START TIME OF -SHRA. A CHANCE OF A FEW
THUNDERSTORMS MAY ALSO BECOME POSSIBLE AS SOME WEAK TO MODEST
INSTABILITY REDEVELOPS IN THE AFTERNOON BUT HAVE LEFT OUT OF THE
TAFS DUE TO LOWER CONFIDENCE AT ANY PARTICULAR SITE. TERMINALS WILL
LOWER BACK TO MVFR/IFR LATER THIS EVENING WHEN THE SYSTEMS COLD FRONT
SHIFTS TOWARD WNY WITH BETTER COVERAGE OF RAIN SHOWERS AND LOWER CIGS.
OUTLOOK...
SATURDAY...SHOWERS TAPERING OFF WITH IMPROVEMENT BACK TO MVFR/VFR.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS
BOTH DAYS.
TUESDAY...VFR.
&&
.MARINE...
A BRIEF PERIOD OF QUIETER AND DRIER WEATHER CAN BE EXPECTED
OVERNIGHT...BEFORE ANOTHER LOW PRESSURE SYSTEM PUSHES EAST FROM THE
CENTRAL GREAT LAKES LATER THIS MORNING AND BRINGS A RETURN OF MORE
SHOWERS AND POSSIBLE THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...THE PRESSURE GRADIENT ACROSS THE LOWER
LAKES WILL REMAIN WEAK OVERNIGHT...BEFORE TIGHTENING A LITTLE LATER
TODAY. COUPLED WITH STABLE TEMPERATURE PROFILES...THIS WILL RESULT IN A
CONTINUATION OF RELATIVELY LIGHT WINDS AND MINIMAL WAVES
TONIGHT...BEFORE THESE INCREASE SOMEWHAT ON LAKE ONTARIO. THE ABOVE
SAID...THESE SHOULD STILL REMAIN BELOW ADVISORY CRITERIA.
BEHIND THE SECOND LOW...A PROGRESSIVELY STRONGER WESTERLY FLOW WILL
SET UP ACROSS THE LOWER LAKES REGION OVER THE WEEKEND...WITH WINDS
AND WAVES POSSIBLY INCREASING TO ADVISORY LEVELS BY SUNDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...JJR/SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...JJR/SMITH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
411 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
TODAY APPEARS A LITTLE QUIETER THEN THE PAST FEW DAYS...AS OUR
STUBBORN UPPER LEVEL LOW IS FINALLY OOZING EAST OF OUR AREA. STILL
HAVE AREAS OF CLOUD COVER TO CONTEND WITH EARLY TODAY. HOWEVER
MOISTURE PROFILES ARE SUCH THAT THERE SHOULD BE A GENERAL CLEARING
THROUGH THE DAY OTHER THEN SOME STRATO CUMULUS POTENTIAL OVER PARTS
OF THE FORECAST AREA WHICH RECEIVED A GOOD WETTING RAINFALL THE PAST
FEW DAYS. BUT AS THE AFTERNOON PROGRESSES...ANY STRATO CUMULUS
POTENTIAL SHOULD DRY UP. WINDS LOOK TO BE FAIRLY LIGHT AHEAD OF
TONIGHTS COLD FRONT. THIS WILL KEEP MIXING POTENTIAL DOWN A BIT...
SO KEPT HIGHS A FEW DEGREES EITHER SIDE OF SEASONAL NORMALS. ONE
THING TO WATCH FOR ARE DEW POINT TEMPERATURES IN OUR FAR WESTERN
ZONES. GUIDANCE DEW POINT VALUES HAVE BEEN CONSISTENTLY TOO HIGH IN
OUR CENTRAL SD ZONES FOR DAYS NOW. DEW POINT READINGS SHOULD RAISE
EARLY TODAY. HOWEVER ONCE THE SURFACE WINDS GO WESTERLY THIS
AFTERNOON AHEAD OF THE COLD FRONT...NOT SURE WHY LOCATIONS AROUND
CHAMBERLAIN WOULD HAVE DEW POINTS IN THE LOWER 40S AS SUGGESTED BY
SOME GUIDANCES. RAP AND HRRR LOOK TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION IN THAT AREA...AND DO INDEED DRY OUT OUR FAR
WESTERN ZONES THIS AFTERNOON. THEREFORE BLENDED THOSE TWO MODELS
INTO SOME OF THE MORE REASONABLE LOOKING CONSENSUS READINGS TO GIVE
DRIER MINIMUM HUMIDITY VALUES IN CENTRAL SD. CONCERNING
PRECIPITATION...AT THE MOMENT IT LOOKS DRY. HOWEVER RIGHT ALONG A
SUBTLE SURFACE CONVERGENCE AXIS WEST OF I 29...MAY NEED TO WATCH FOR
A FEW SPRINKLES OR AN ISOLATED LIGHT SHOWER EARLY TODAY IN THOSE
LOCATIONS.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
COLD FRONT PROGGED TO CROSS THE CWA TONIGHT...ENTERING THE
NORTHWEST PORTION OF OUR CWA BY 03Z AND EXITING NORTHWEST IOWA BY
09Z. BEST LARGE SCALE FORCING AND DEEPER MOISTURE STAYS OFF TO OUR
NORTHEAST. THUS THE GREATEST PRECIP POTENTIAL SHOULD BE NORTHEAST OF
US OVER MINNESOTA...WITH OUR AREA HAVING TO RELY ON ANY CONVECTION
THAT CAN GET GOING. HOWEVER IT IS A DECENT FRONTAL BOUNDARY...WITH
POTENTIALLY JUST ENOUGH LOW TO MID LEVEL THETAE ADVECTION TO INDEED
KICK OFF A FEW SHOWERS...THUS WILL KEEP THE LOW POPS GOING. JUST
ENOUGH INSTABILITY TO MAYBE GET A FEW RUMBLES OF THUNDER AS WELL.
DECENT LOW LEVEL JET OF WINDS BEHIND THE FRONT WITH A QUICK SHOT OF
CAA AS WELL. THUS NOT SURPRISING THAT MODEL SOUNDINGS SHOW THE
OPPORTUNITY FOR A PERIOD OF GUSTY WINDS RIGHT BEHIND THE FRONT
TONIGHT. MAY BE ABLE TO GET SOME 40 MPH GUSTS DOWN TO THE SURFACE
FOR A FEW HOURS FOLLOWING THE FRONTAL BOUNDARY AS WE MIX INTO THE 30
TO 40 KT JET. SO SOMETHING TO KEEP AN EYE ON.
EXPECT WINDS TO DROP OFF SOME SATURDAY MORNING AS MIXING WEAKENS A
BIT AND THE JET PUSHES SOUTHEAST OF THE AREA. HOWEVER AS DEEPER
MIXING BEGINS WITH DAYTIME HEATING WINDS WILL ONCE AGAIN INCREASE.
NORTHERLY WINDS GUSTING 25 TO 35 MPH LOOK LIKELY FROM MID MORNING
INTO THE AFTERNOON HOURS. IT WILL BE A CHILLY ONE TOO...WITH HIGHS
RANGING FROM THE LOW 50S OVER SOUTHWEST MINNESOTA TO AROUND 60 ALONG
THE MISSOURI RIVER. SHOULD AT LEAST BE MOSTLY SUNNY THOUGH...WITH
JUST A FEW AFTERNOON FAIR WEATHER CU. SURFACE HIGH PRESSURE QUICKLY
BUILDS IN SATURDAY NIGHT...WITH IDEAL RADIATIONAL COOLING EXPECTED
OVER MOST OF THE CWA. GIVEN THE COOL LOW LEVEL TEMPERATURE PROFILES
IN PLACE...EXPECTING A COLD NIGHT. WENT AT OR BELOW THE COLDEST
GUIDANCE...WITH UPPER 20S TO LOW 30S OVER MOST OF THE AREA. HOWEVER
IF CURRENT TRENDS PERSIST...WOULD NOT BE SURPRISED TO SEE SOME MID
20S IN SOME OF THE COOLER LOCATIONS EAST OF THE JAMES RIVER.
NEEDLESS TO SAY...LOOKS LIKE FROST OR FREEZE HEADLINES WILL BE
NEEDED FOR MOST OF THE CWA.
THE TROUGH EXITS TO OUR EAST ON SUNDAY...ALLOWING FOR A SLOW WARMUP
TO BEGIN. HIGHS WILL STILL BE BELOW NORMAL THOUGH...WITH UPPER 50S
AND LOW 60S EAST AND UPPER 60S WEST. WINDS WILL BE PRETTY LIGHT AND
THE SUN SHOULD BE SHINING BRIGHT...THUS NOT A BAD DAY OVERALL. OUR
REAL WARMTH BEGINS TO MOVE IN MONDAY AS UPPER RIDGING BUILDS IN.
HIGHS MONDAY A BIT TRICKY...WITH A SHARP GRADIENT LIKELY. AROUND 90
SEEMS ALMOST CERTAIN IN SOUTH CENTRAL SOUTH DAKOTA THOUGH...WITH THE
GREATER UNCERTAINTY TO THE EAST. MODELS BOUNCING AROUND A BIT ON HOW
QUICKLY WARM AIR MOVES IN EAST OF THE JAMES...BUT MID 70S TO MID 80S
LOOK PROBABLE. TUESDAY SHOULD BE THE HOTTEST DAY OF THE YEAR THUS
FAR. MODELS HAVE SLOWED DOWN THE WEAK FRONT...MEANING WE SHOULD GET
THE FULL FORCE OF THE HEAT. 850MB TEMPERATURES ARE QUITE
IMPRESSIVE...RUNNING CLOSE TO THE CLIMATOLOGICAL MAX FOR THIS TIME
OF YEAR. WENT WELL ABOVE ALLBLEND FOR HIGHS...WITH UPPER 80S TO LOW
90S LOOKING LIKE A GOOD BET FOR THE ENTIRE CWA. HOWEVER...IT SEEMS
QUITE POSSIBLE THAT AN AREA OF MID TO UPPER 90S WILL OCCUR IN A
CORRIDOR JUST AHEAD OF THE FRONT. TRYING TO PIN DOWN WHERE THIS WILL
OCCUR IS TOUGH THIS FAR OUT...AS IT COULD REALISTICALLY BE AS FAR
WEST AS CENTRAL SOUTH DAKOTA...OR AS SOUTHEAST AS NORTHWEST IOWA.
THUS DID NOT WANT TO GO TOO HIGH WITH FORECAST MAXES THIS FAR
OUT...GIVEN THE CURRENT FORECAST IS ALREADY 20 DEGREES ABOVE NORMAL.
MODELS DIVERGE A BIT AFTER TUESDAY...BUT GENERAL CONSENSUS IS FOR
THE RIDGE TO FLATTEN AS WAVES TO OUR NORTH PUSH A FRONTAL BOUNDARY
SOUTH THROUGH THE NORTHERN PLAINS. STRENGTH OF THIS BOUNDARY STILL
UNCERTAIN...BUT EITHER WAY IT SHOULD BE COOLER WEDNESDAY AND
THURSDAY...WITH HIGHS EITHER IN THE 70S OR 80S DEPENDING ON FRONTAL
STRENGTH. PRECIP CHANCES TOUGH TO PIN DOWN...OTHER THAN THAT IT
LOOKS LIKE THERE GOOD BE SOME ISOLATED TO SCATTERED CONVECTION
ANYTIME TUESDAY NIGHT ON AS THE WEAK WAVES AND FRONTS PUSH
ACROSS...BUT NOT EXPECTING ANYTHING WIDESPREAD OR SIGNIFICANT AT
THIS POINT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1129 PM CDT THU MAY 9 2013
MVFR CEILINGS WILL CONTINUE TO PLAGUE AREAS FROM AROUND INTERSTATE
29 AND EASTWARD FOR MUCH OF TONIGHT AND EARLY MORNING AS LOW LEVEL
FLOW REMAINS WITH AN EASTERLY COMPONENT. DRIER AIR IN CENTRAL
MINNESOTA WILL EVENTUALLY HELP TO ERODE FROM THE NORTHEAST LATER
TONIGHT AND THROUGH MID MORNING ON FRIDAY...BUT WILL LIKELY LEAVE
A NORTH/SOUTH BAND OF STRATUS THAT WILL BE MORE DIFFICULT TO ERODE
BETWEEN THE JAMES VALLEY AND I 29...PERHAPS REMAINING UNTIL LATE
MORNING. OTHERWISE...WILL LIKELY CONTINUE TO SEE SOME ISOLATED SHOWER
DEVELOPMENT THROUGH 09Z-10Z THROUGH THE JAMES VALLEY AS WEAK LOW
LEVEL CONVERGENCE CONTINUES...WITH MARGINALLY WEAK INSTABILITY IN
THE MID LEVELS...BUT BELOW THRESHOLD FOR MENTION IN KHON TAF. A
STRONG COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY EVENING.
SOME INSTABILITY FOR THUNDER THREAT...BUT MAINLY FOR AREAS
NORTHEAST OF A KHON TO KFSD TO KSPW LINE...AND WILL BE MAINLY AT
AND POST FRONTAL FOR A COUPLE HOURS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJF
LONG TERM...CHENARD
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
327 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CDT FRI MAY 10 2013
MAIN FORECAST CONCERN IS WITH THE IMPACTS OF A COLD FRONT TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST INTO BRITISH COLUMBIA...A POTENT
SHORTWAVE TROUGH DROPPING INTO CENTRAL SASKATCHEWAN...AND A WEAK
SHORTWAVE TROUGH OVER CENTRAL WISCONSIN. THE LATTER SHORTWAVE TROUGH
WAS RESPONSIBLE FOR THE WET WEATHER YESTERDAY...WHICH LATEST RADAR
IMAGERY STILL SHOWS SCATTERED SHOWERS AND DRIZZLE OVER THE SOUTHEAST
HALF OF THE FORECAST AREA. CLOUDS ASSOCIATED WITH THE SHORTWAVE
ENCOMPASS MUCH OF THE FORECAST AREA...BUT HAVE CLEARED OUT ACROSS
NORTH DAKOTA INTO THE NORTHERN 2/3 OF MINNESOTA AND NORTHWEST WI.
00Z BIS AND ABR SOUNDINGS WERE VERY DRY BELOW 700MB WITH DEWPOINT
DEPRESSIONS OF 15C OR GREATER. THIS DRY AIR WAS ASSOCIATED WITH A
SURFACE RIDGE OF HIGH PRESSURE. A TIGHT PRESSURE GRADIENT AHEAD OF
THE HIGH AND LOW PRESSURE MOVING THROUGH NORTHERN ILLINOIS HAS
RESULTED IN SOME GUSTY NORTHEAST WINDS ACROSS THE FORECAST AREA.
COOLER AIR TOO WITH THE HIGH PRESSURE RIDGE...REFLECTED BY 850MB
TEMPS AT 00Z OF 5-7C FROM BIS TO MPX...COMPARED TO 10C AT DVN. TO
THE NORTHWEST...BEHIND THE POTENT SHORTWAVE TROUGH...MUCH COLDER
AIR EXISTS. -2C 850MB TEMPS WERE OBSERVED AT 00Z OVER NORTHERN
ALBERTA. THE COLD FRONT ASSOCIATED WITH THE TROUGH WAS IN SOUTHEAST
SASKATCHEWAN.
THE HIGH PRESSURE RIDGE AND ITS DRY AIR ARE FORECAST TO MOVE INTO
THE CWA THROUGH THE DAY...WITH THE RIDGE OVERHEAD AT 00Z. THUS...WE
WILL SEE GRADUAL CLEARING NORTHWEST TO SOUTHEAST THROUGH THE DAY.
MAY STILL HAVE TO CONTEND WITH SOME LINGERING SHOWERS TOO IN THE
SOUTHEAST SECTION OF THE FORECAST AREA UNTIL 15Z. TEMPERATURES ARE
LIKELY TO STRUGGLE TO RISE THIS MORNING WITH COLD ADVECTION AND
CLOUDS IN PLACE...BUT SHOULD BE ABLE TO CLIMB INTO THE LOW TO MID
60S BY LATE IN THE DAY WITH THE SUN AND 850MB TEMPS OF 4-5C.
MODELS ARE IN GOOD AGREEMENT TAKING THE POTENT SHORTWAVE TROUGH
OVER CENTRAL SASKATCHEWAN INTO NORTHWEST ONTARIO TONIGHT...WITH
ANOTHER STRONG SHORTWAVE DIGGING IN BEHIND IT INTO CENTRAL MINNESOTA
BY 12Z SATURDAY. THE 500MB HEIGHT FALLS ARE QUITE IMPRESSIVE BETWEEN
00-12Z...FROM AROUND 100 METERS ALONG I-90 TO ALMOST 200 METERS OVER
WESTERN LAKE SUPERIOR. NEEDLESS TO SAY...PLENTY OF DYNAMIC FORCING.
ONE HUGE PROBLEM IS THE LACK OF MOISTURE... ESPECIALLY AHEAD OF THE
TROUGH PER THE 00Z BIS SOUNDING. THUS...NO PRECIPITATION WILL OCCUR
AHEAD OF THE COLD FRONT ACCOMPANYING THE TROUGH...WHICH IS PROGGED
TO CROSS THE AREA BETWEEN 06-12Z. IF PRECIPITATION OCCURS...IT HAS
TO OCCUR THEN POST-FRONTAL...IN THE COOLER AIR. CROSS-SECTIONS SHOW
A FAIRLY STRONG LOW LEVEL FRONTOGENESIS-FRONTOLYSIS COUPLET...ALONG
WITH SOME NEGATIVE EPV BEING INGESTED INTO THIS CIRCULATION. WITH
ALL THE FORCING PRESENT...HAVE TO IMAGINE A NARROW BAND OF SHOWERS
COMING THROUGH BEHIND THE FRONT. THERE MAY EVEN BE A RUMBLE OR TWO
OF THUNDER GIVEN THE NEGATIVE EPV SIGNAL...BUT THE CHANCE AND
COVERAGE IS TOO LOW TO MENTION. EXPECT WINDS TOO TO RAPIDLY INCREASE
OUT OF THE NORTHWEST BEHIND THE FRONT...AIDED BY ISALLOBARIC
FORCING. SOME PLACES...LIKE ROCHESTER AND DODGE CENTER...COULD GUST
CLOSE TO WIND ADVISORY...ESPECIALLY WITH THE SHOWERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 327 AM CDT FRI MAY 10 2013
DEEP TROUGHING IS PROGGED TO PERSIST OVER THE GREAT LAKES MUCH OF
THE WEEKEND...RESULTING FROM THE POTENT SHORTWAVE TROUGH DIGGING
TOWARDS THE AREA TONIGHT. 500MB STANDARDIZED ANOMALIES ARE 1.5-2
BELOW NORMAL ALONG WITH 850MB ANOMALIES OF 2 BELOW NORMAL. THESE LOW
ANOMALIES RESULT IN A VARIETY OF ISSUES:
1. TEMPERATURES. CHILLY HIGHS AND LOWS ARE LIKELY...AND COULD GET
CLOSE TO RECORDS SOLELY BASED ON THE 850MB ANOMALIES. LA CROSSE
RECORD LOWS ARE AROUND 30 WHILE ROCHESTER IS AROUND 26. THE BIGGEST
PROBLEM WITH TEMPERATURES ARE THE WINDS. CONTINUOUS COLD ADVECTION
THROUGH SATURDAY NIGHT WILL HELP KEEP THE BOUNDARY LAYER MIXED...AND
WITH 925MB WINDS STILL AT 20-25 KT AT 12Z SUNDAY...EXPECTING
DIFFICULT CONDITIONS TO DECOUPLE. BETTER SHOT OF DECOUPLING TAKES
PLACE SUNDAY EVENING...BUT WARM ADVECTION TAKES HOLD AFTER
MIDNIGHT. FOR NOW HAVE TAKEN A BLEND OF MOS AND RAW MODEL GUIDANCE
FOR HIGHS AND LOWS...GIVEN THE UNCERTAINTY ON DECOUPLING.
2. WINDS...STRONG SUBSIDENCE FLOWS INTO THE AREA ON SATURDAY WILL
COMBINE WITH LOW LEVEL UNIDIRECTIONAL NORTHWEST FLOW...THE STRONG
MIXING FROM THE MAY SUN...AND COLD ADVECTION TO RESULT IN A BLUSTERY
DAY. WE COULD MIX TO 775 MB OR HIGHER. MOMENTUM TRANSFER OF THE
WINDS AT THAT LEVEL OF 40-45 KT RESULTS IN GUSTS OF 30-35 KT AT THE
SURFACE...JUST BELOW ADVISORY CRITERIA. WINDS SLOWLY DIMINISH
SATURDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE
PLAINS.
3. FROST/FREEZE. CONNECTING WITH THE TEMPERATURES AND WINDS ABOVE...
FROST LOOKS VERY DIFFICULT TO FORM SATURDAY NIGHT. ADDITIONALLY...
RELATIVE HUMIDITIES MAY NOT EXCEED 80 PERCENT DUE TO DRY ADVECTION.
IF ANYTHING...THE CONCERN WOULD COME FROM A FREEZE DUE TO THE
TEMPERATURES...IF THEY FALL BELOW FREEZING. BETTER SHOT OF FROST
WOULD COME SUNDAY NIGHT...DEPENDING ON WHEN HIGH CLOUDS AND THE WARM
AIR SPREADS IN. FROST LOOKS MOST LIKELY IN CENTRAL WISCONSIN.
4. PRECIPITATION...COLD POOL OF 500MB TEMPS OF -30C LOOKS TO CROSS
TAYLOR COUNTY MID-DAY SATURDAY. DAYTIME MIXING COMBINED WITH THE
MOISTURE WITH THIS COLD POOL COULD GENERATE A FEW SHOWERS ACROSS
TAYLOR/CLARK COUNTIES. HAVE KEPT 20 PERCENT CHANCES GOING FOR THESE.
OTHERWISE...DRY CONDITIONS EXPECTED TO PREVAIL.
FOR NEXT WEEK...THE BIG HIGHLIGHT IS TUESDAY AND WEDNESDAY WITH A
CONSISTENTLY SHOWN STRONG SURGE OF WARM AIR. THERE IS VERY STRONG
MODEL AGREEMENT OF TROUGHING COMING INTO THE PACIFIC NORTHWEST EARLY
NEXT WEEK...SHOVING A RIDGE TOWARDS THE FORECAST AREA. A LOW
POTENTIAL EXISTS FOR SOME SHOWERS AND THUNDERSTORMS AS THE RIDGE
APPROACHES MONDAY AFTERNOON INTO MONDAY NIGHT. HEADING INTO
TUESDAY...850MB STANDARDIZED ANOMALIES JUMP TO 2-2.5 ABOVE...
SUGGESTING POTENTIAL RECORD HIGHS. THERE ARE TWO ISSUES ON TUESDAY
TO CONTEND WITH...TIMING OF THE SURFACE WARM FRONT AND HOW DRY THE
AIR IS IN THE WAKE OF THE FRONT. THE 09.12Z/10.00Z GFS WERE IN GREAT
AGREEMENT PUSHING THE WARM FRONT THROUGH THE AREA ON TUESDAY...
LIKELY RESULTING IN HIGHS IN THE 80S TO POSSIBLY LOW 90S.
HOWEVER...THE 10.00Z ECMWF/CANADIAN ONLY GET THE WARM FRONT TO THE
MISSISSIPPI RIVER. WITH 850MB TEMPS OF 20C+ IN THE WAKE OF THE
FRONT...TIMING OF THE FRONT IS CRITICAL. ON THE MOISTURE SIDE...THE
GFS AND ECMWF WANT TO BRING DEWPOINTS UP INTO THE 60S...BUT THIS
SEEMS WAY TOO HIGH GIVEN THE LACK OF CORN CROPS TO THE SOUTH AND THE
WARM SURGE BEING OF ROCKIES ORIGIN. THUS...DEEPER MIXING IS LIKELY
BEHIND THE FRONT. NEXT CONCERN IS WHEN DOES A COLD FRONT COME
THROUGH. THE 10.00Z ECMWF/CANADIAN REALLY SLOWED THIS DOWN...NOT
CROSSING TIL THURSDAY. IF THIS COMES TRUE...HIGHS WEDNESDAY
COULD TOUCH 90. ON THE OTHER HAND...A FASTER FRONT FROM THE 10.00Z
GFS WOULD KEEP HIGHS IN THE 70S. SPLIT THE DIFFERENCE FOR HIGHS ON
WEDNESDAY FOR NOW. ALSO...MAINTAINED A 20-30 PERCENT CHANCE FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH THURSDAY FOR THE
FRONT...WITH WEDNESDAYS CHANCES IN CASE THE FRONT ENDS UP BEING
FASTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1100 PM CDT THU MAY 9 2013
RAIN CONTINUES TO FALL NORTH OF AN AREA OF LOW PRESSURE...WHICH WAS
TRACKING WEST TO EAST ACROSS NORTHWEST IL. A FEW TS JUST NORTH OF
THE LOW...BUT INSTABILITY STAYS SOUTH...AND DON/T SEE A TS THREAT AT
KRST/KLSE. WITH THE EXIT OF THE LOW...THE PCPN IS COMING TO AN END.
CLOUDS WILL HANG AROUND...AND SHOULD HOLD MVFR/IFR THROUGH
MUCH OF FRI MORNING. BUFKIT SOUNDINGS INDICATE A MIXING OUT OF THIS
LOW CLOUD LAYER FRIDAY AFTERNOON...WITH RH FIELDS ALSO DEPICTING A
DECREASE IN SATURATION. EXPECT A DIURNAL BUMP UPWARD OF CIGS BY THE
AFTERNOON...AND SCATTERING OUT BEFORE THE EVENING. THAT SAID...THERE
COULD BE FURTHER CU DEVELOPMENT POST THE LOW/S ASSOCIATED CLOUD
SHIELD. IF SO...ANOTHER BKN CIG COULD DEVELOP QUICKLY...BUT WOULD
JUST AS QUICKLY SCATTER OUT WITH THE LOSS OF DAYTIME HEATING.
FOR VSBYS...LATEST SFC OBS ARE MOSTLY P6SM...EVEN IN THOSE AREAS
WITH -RA. WINDS WILL STAY UP TONIGHT/FRIDAY...ENOUGH TO KEEP THE
ATMOSPHERE STIRRED...AND DON/T EXPECT BR/FG DEVELOPMENT AS A RESULT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
851 AM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 848 AM MDT FRI MAY 10 2013
UPDATED FORECAST GRIDS AND ZONES TO REFLECT CURRENT CONDITIONS...WITH
GENERALLY CLEAR SKIES ACROSS THE CWA...AND A BAND OF MID LEVEL CLOUDS
MOVING SWD ACROSS THE PALMER DVD AND INTO N EL PASO. ALSO REDUCED
POPS AND TAPERED PRECIP CHANCES TOWARDS LATER THIS AFTERNOON. HRRR IDEA
OF BRINGING SCT SHOWERS ACROSS THE PLAINS BY MID TO LATE AFTERNOON LOOKS
REASONABLE...ALONG WITH BETTER COVERAGE ACROSS THE MTS. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI MAY 10 2013
THE UPPER TROF AXIS WILL CONTINUE TO SHIFT SOUTH OF THE AREA TODAY
WITH SOME TRAILING ENERGY ACROSS SRN WY/NRN CO SINKING ACROSS SE CO
DURING THE AFTERNOON. RESIDUAL MOISTURE COMBINED WITH THIS TRAILING
ENERGY FIRE OFF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ACROSS
THE MOUNTAINS DURING THE LATE MORNING WITH COVERAGE INCREASING
DURING THE AFTERNOON AS THEY SPREAD INTO THE ADJACENT VALLEYS AND
PORTIONS OF THE I-25 CORRIDOR. STEERING CURRENTS WILL BE MORE
NORTHERLY TODAY...WHICH SHOULD KEEP MAJORITY SHOWERS/TSTORMS OVER
THE MOUNTAINS. THE EXCEPTION TO THIS WILL BE ACROSS THE PALMER
DIVIDE WHERE SHORT RANGE MODELS INITIATE THUNDERSTORMS ACROSS THE
ELEVATED TERRAIN AND ALONG A WEAK WIND SHIFT BOUNDARY DURING THE
AFTERNOON. MODEL SOUNDINGS SHOW ONLY 100-200 J/KG OF CAPE ACROSS THE
MOUNTAINS AND LCLS LOOK HIGHER THAN PAST COUPLE DAYS...AROUND
625-650 MB. SO ALTHOUGH THE WALDO CANYON BURN SCAR WILL NEED TO BE
MONITORED CLOSELY FOR ANY STRONGER SHOWERS AND THUNDERSTORMS THAT
MIGHT DEVELOP...ESPECIALLY DUE TO THE SATURATED GROUND...THE CHANCES
THAT RAINFALL RATES WILL BE HIGH ENOUGH TO CAUSE A SIGNIFICANT
THREAT OF FLASH FLOODING LOOK LOW AT THIS POINT. THEREFORE WILL NOT
ISSUE ANY FLASH FLOOD WATCHES. HOWEVER THIS DOESN`T MEAN THE
POSSIBILITY DOESN`T EXIST AND THIS WILL NEED TO BE
MONITORED...ESPECIALLY IF DEW POINTS DON`T DROP OFF AS FAST AS
MODELS INDICATE.
CONVECTION DIES OFF QUICKLY DURING THE EVENING WITH ANOTHER
NORTHERLY SURGE DROPPING THROUGH THE SOUTHEAST PLAINS TOWARDS DAWN.
THIS MAY HELP HOLD TEMPERATURES UP A COUPLE DEGREES...KEEPING LOWS
IN THE LOWER 40S. OTHERWISE EXPECT CLEARING SKIES TOWARDS MORNING.
-KT
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI MAY 10 2013
NOT MUCH CHANGE TO THE FORECAST THINKING FOR THE EXTENDED. HIGH
PRESSURE WILL BUILD ACROSS THE GREAT BASIN ON SATURDAY WHILE A
STRONG LOW SPINS OVER EASTERN CANADA. THIS WILL PUT SOUTHERN
COLORADO UNDER NORTHWESTERLY FLOW ALOFT. MODELS INDICATING A WEAK
DISTURBANCE MOVING THROUGH THE FLOW. THIS DISTURBANCE COMBINED
WITH RESIDUAL MOISTURE FROM RECENT RAINFALL WILL LIKELY PRODUCE AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS AND
PALMER DIVIDE. LIGHTNING AND GUSTY OUTFLOW WINDS WILL LIKELY BE
THE PRIMARY THREATS. GIVEN THE CONVECTIVE NATURE...ANY SHOWERS OR
THUNDERSTORMS THAT DEVELOP OVER THE WALDO CANYON BURN SCAR COULD
PRODUCE LOCALLY HEAVY RAINFALL AND POSSIBLE FLASH FLOODING.
AFTERNOON HIGHS WILL REMAIN IN THE UPPER 60S TO LOWER 70S ACROSS
THE PLAINS. EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DISSIPATE
THROUGH 3AM.
THE HIGH PRESSURE OVER THE GREAT BASIN WILL SHIFT EAST ACROSS
COLORADO SUNDAY AND MONDAY. THIS WILL BRING DRIER AIR INTO THE
ROCKIES AND WEAK STEERING FLOWS ALOFT. MODELS GENERATING MORE
ISOLATED SHOWER AND THUNDERSTORM ACTIVITY EACH AFTERNOON AND
EVENING SUNDAY AND MONDAY. GIVEN THE WEAK STEERING FLOWS NOT
ANTICIPATING MUCH STORM MOVEMENT. TEMPERATURES ALOFT WARM AND
HEIGHTS RISE WHICH WILL HELP AFTERNOON HIGHS WARM INTO THE UPPER
70S TO MID 80S ACROSS THE PLAINS.
THE UPPER RIDGE IS FORECAST TO SHIFT EAST INTO THE CENTRAL PLAINS
ON TUESDAY WHILE A STRONG SHORTWAVE TROUGH MOVES OUT OF THE
PACIFIC NORTHWEST INTO THE NORTHERN PLAINS THROUGH THE MIDDLE OF
THE WEEK. THIS WILL SEND A COLD FRONT INTO THE AREA TUESDAY EVENING.
MODELS WANTING TO DEVELOP THUNDERSTORM ACTIVITY ACROSS THE PLAINS
LATE TUESDAY AFTERNOON INTO THE EVENING HOURS...BUT LACK OF
MOISTURE MAY INHIBIT DEVELOPMENT. FOR NOW DO NOT HAVE
THUNDERSTORMS IN THE FORECAST FOR THE PLAINS...BUT THIS WILL NEED
TO BE MONITORED. AFTERNOON HIGHS ON TUESDAY AHEAD OF THE COLD
FRONT WILL REACH INTO THE MID 80S ON THE PLAINS. HIGHS BEHIND THE
COLD FRONT WEDNESDAY THROUGH FRIDAY WILL REMAIN IN THE MID 70S TO
LOWER 80S. SHOWER AND THUNDERSTORM ACTIVITY WILL REMAIN POSSIBLE
OVER THE MOUNTAIN AREAS THROUGH THE END OF THE WEEK. MOZLEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 343 AM MDT FRI MAY 10 2013
VFR CONDITIONS EXPECTED AT THE TAF SITES THROUGH MOST OF THE DAY.
KPUB COULD SEE SOME PATCHY FOG THIS MORNING WITH VIS DROPPING INTO
THE MVFR CATEGORY. ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP
OVER THE MOUNTAINS DURING THE AFTERNOON...PRODUCING MVFR TO LOCAL
IFR CIGS WITH THE STRONGER SHOWERS/TSTORMS. KCOS WILL SEE THE BEST
CHANCE FOR VCSH/VCTS DURING THE AFTERNOON WITH VFR TO POSSIBLY BRIEF
MVFR CIGS...WHILE KPUB AND KALS ARE MORE LIKELY TO REMAIN DRY.
CONVECTION SHOULD DIMINISH QUICKLY THIS EVENING WITH LIGHT WINDS AND
CLEARING SKIES. ANOTHER NORTHERLY SURGE DROPS THROUGH THE PLAINS
AFTER 06Z WHICH COULD BRING SOME ENHANCED NORTHERLY WINDS 10-15 KTS
AT KCOS TOWARDS 12Z. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...KT
LONG TERM...MOZLEY
AVIATION...KT
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1008 AM EDT FRI MAY 10 2013
.DISCUSSION...THE LOW LEVEL ATLANTIC RIDGE AXIS IS JUST NORTH OF THE
AREA BRINGING A LIGHT SOUTH-SOUTHEASTERLY FLOW ACROSS EAST CENTRAL
FLORIDA THIS MORNING. THIS WIND FLOW HAS TAPPED INTO THE MOISTER
ATMOSPHERE TO OUR SOUTH...BRINGING PWATS UP TO AROUND AN INCH ACROSS
THE NORTH THIS MORNING AND CLOSER TO 1.25" ACROSS THE TREASURE
COAST. HOWEVER THE SOUNDINGS SHOW CONSIDERABLE DRY AIR IN THE MID
LEVELS WITH THE CURRENT RUC ANALYSIS CAPPING 850-500MB RH VALUES AT
25-30 PERCENT. MOISTURE ADVECTION AT ALL LEVEL WILL CONTINUE
TODAY...THOUGH THE MID LEVELS WILL BE SLOWER TO INCREASE.
WITH THE DRIER AIR STILL IN PLACE...SHOWERS AND STORMS WILL BE SLOW
TO GET GOING TODAY THOUGH A FEW WILL BE POSSIBLE LATE THIS
MORNING/EARLY THIS AFTERNOON AS THE REMNANTS OF THE EARLIER ATLANTIC
ACTIVITY MOVE INTO THE COAST. ONE OR TWO MAY POP UP ON THE SEA
BREEZE THROUGH MID AFTERNOON...ESPECIALLY WHERE IT INTERACTIONS WITH
THE LAKE OKEECHOBEE BREEZE. HOWEVER THE BEST CHANCES WILL WAIT FOR
THE LATE AFTERNOON/EVENING COLLISION OF THE EAST AND WEST COAST SEA
BREEZES FROM LAKE GEORGE THROUGH THE ORLANDO METRO AND SOUTHWARDS TO
LAKE OKEECHOBEE. ANY CONVECTION THAT DEVELOPS FROM THE SEA BREEZE
COLLISION MAY SHIFT BACK TOWARD THE EAST COAST THIS
EVENING...ESPECIALLY NORTH OF THE CAPE. WARM TEMPS AND PARTLY SUNNY
SKIES EXPECTED FOR MUCH OF THE DAY WITH HIGHS REACHING THE MID 80S
AT THE COAST TO UPPER 80S/AROUND 90 DEGREES INLAND.
&&
.AVIATION...THROUGH 16Z...PREVAILING VFR WITH LCL CIGS FL020-030 IN
DEVELOPING CU ALONG COAST SOUTH OF KMLB. BRIEF -SHRA POSSIBLE SOUTH
OF KFPR. 16Z-21Z...ISOLD SHRA/TSRA DEVELOPING ALONG SEA BREEZE SOUTH
OF KTIX JUST INLAND FROM THE COAST. AFTER 21Z...SEA BREEZE COLLISION
TOWARD THE I-4 CORRIDOR AROUND SUNSET WILL BRING BEST CHANCE FOR
SHOWER/STORM DEVELOPMENT WITH TEMPO IFR/MVFR CONDS EXPECTED WITH
THIS ACTIVITY. A FEW STORMS WILL DRIFT BACK TOWARDS KDAB-KTIX LATE
IN THE EVENING.
&&
.MARINE...SOUTH-SOUTHEAST WINDS GENERALLY AROUND 10KTS THROUGH THE
PERIOD...CREEPING UP TO 10-15KTS NEAR THE COAST WITH THE AFTERNOON
SEA BREEZE DEVELOPMENT. SEAS 2-3 FEET. A FEW STORMS MAY DEVELOP
ALONG THE INTRACOASTAL WATERS THIS AFTERNOON AND MOVE OFFSHORE NORTH
OF THE CAPE THIS EVENING.
&&
.FIRE WEATHER...MIN RH MAY APPROACH AROUND 35 PERCENT FOR A FEW
HOURS FROM THE I-4 CORRIDOR WESTWARD THIS AFTERNOON BUT WINDS AND
ERC VALUES WILL REMAIN BELOW CRITICAL VALUES. A FEW LIGHTNING STORMS
EXPECTED TO DEVELOP FROM THE SEA BREEZE COLLISION ACROSS THE
INTERIOR AROUND SUNSET.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
MOSES/LASCODY
AREA FORECAST DISCUSSION
NWS MIAMI FL
1007 AM EDT FRI MAY 10 2013
.UPDATE...
LOOKING TO BE A VERY TRICKY FORECAST THIS MORNING. A WEAK MID
LEVEL TROUGH MOVED ACROSS SOUTH FLORIDA DURING THE LATE AFTERNOON
YESTERDAY AND LAST NIGHT SPARKING CONVECTION PARTICULARLY OFFSHORE
THIS MORNING WHICH THEN BUILT BACK ONSHORE. THAT CONVECTION HAS
NOW WANED AS THE TROUGH CONTINUES TO MOVE EAST. THE INTERESTING
PHENOMENA THIS MORNING IS THE 12Z MFL SOUNDING WHICH SHOWS
SIGNIFICANT WARMING AT 500 MB WITH A DISTINCT INVERSION WHICH IS
NEARLY 5K FEET DEEP. THERE HAS ALSO BEEN SOME DRYING ALOFT WITH
PWAT NOW DOWN TO ABOUT 1.25 INCHES WHICH IS SLIGHTLY BELOW THE
AVERAGE FOR EARLY MAY. SO THE QUESTION IS HOW MUCH OF A FACTOR
WILL THESE TWO CONDITIONS HAVE ON CONVECTION DEVELOPING. THE LOW
LEVELS REMAIN SOMEWHAT UNSTABLE BUT THE OVERALL SOUNDING WOULD
MAKE ME BELIEVE THAT CONVECTION WILL STRUGGLE TO BUILD PAST THE
SHOWER STAGE. HOWEVER, MODEL FORECAST SOUNDINGS SHOW MID LEVEL
MOISTURE RETURN ALTHOUGH IT APPEARS THAT THEY MAY BE SUFFERING
FROM CONVECTIVE FEEDBACK. THE MORNING PROFILE ALSO INDICATES VERY
SLOW STORM MOTION TODAY AT UNDER 5 KNOTS WITH A DRIFT BACK TOWARDS
THE EAST COAST LATE IN THE DAY. THE EARLY MORNING HRRR RUNS
INITIALIZED NEARLY PERFECTLY AND SHOW INTERIOR CONVECTION
DEVELOPING OVER THE INTERIOR BETWEEN 17-18Z AND MOVING LITTLE. IT
WILL BE INTERESTING TO SEE WHAT THE LATER RUNS ILLUSTRATE AFTER IT
INGESTS THE 12Z SOUNDINGS. AT ANY RATE, FEEL THE NEED TO SCALE
BACK TO SLIGHT CHANCE THUNDER OVER THE INTERIOR AND CAN MAKE LATER
ASSESSMENTS AS THINGS MATERIALIZE.
KOB
&&
.PREV DISCUSSION... /ISSUED 648 AM EDT FRI MAY 10 2013/
AVIATION...
WITH SURFACE HIGH PRESSURE WELL THE THE EAST NORTHEAST, THERE WILL
BE A SOUTHEASTERLY FLOW OVER SOUTH FLORIDA TODAY. THIS WILL ALSO
CONTINUE TO BRING IN SOME MOISTURE TO THE AREA. THIS COULD LEAD TO
AN AFTERNOON SHOWER OR THUNDERSTORM IN THE INTERIOR SECTIONS OF
SOUTH FLORIDA. HOWEVER, IT IS VERY UNCERTAIN IF ANY THUNDERSTORMS,
THAT MAY BE ABLE TO DEVELOP, WILL DRIFT CLOSE ENOUGH TO THE COAST
TO AFFECT ANY OF THE TAF SITES. SO, HAVE NOT MENTIONED THEM AS OF
YET IN THE TAFS. GIVEN THIS, A VFR DAY IS EXPECTED WITH WINDS FROM
THE SE AROUND 10 KTS, BECOMING LIGHT AND VARIABLE IN THE LATE
EVENING.
PREV DISCUSSION... /ISSUED 334 AM EDT FRI MAY 10 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUED OVER THE ATLANTIC WATERS JUST
EAST OF THE MIAMI-DADE/BROWARD COUNTY BORDER. A FEW SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED OVER THE METRO AREAS. THESE
SHOWERS AND STORMS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS
A SHORTWAVE EXITS THE REGION.
UPPER RIDGING OVER THE CENTRAL GULF STRETCHING INTO THE LOWER
GREAT LAKES WILL SHIFT EAST TODAY AS A SHORTWAVE TROUGH MOVES FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY. UPPER HEIGHTS WILL
INCREASE OVER SOUTH FLORIDA...WITH MUCH WARMER AND SOMEWHAT DRIER
AIR ALOFT THAN ON THURSDAY. HOWEVER...LOW LEVEL MOISTURE WILL
REMAIN IN PLACE WITH DEWPOINTS IN THE MID 60S TO AROUND 70...SO
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG
THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR THIS AFTERNOON INTO
THE EARLY EVENING. A LIMITING FACTOR EACH DAY THROUGH THE WEEKEND
WILL BE THE SUBTROPICAL RIDGE OVER THE REGION...WITH WARM AND DRY
AIR FROM 850MB TO 600MB. EASTERLY LOW LEVEL FLOW AND LIGHT WINDS
ALOFT WILL ALLOW FOR SLOW STORM MOTION AND FOR STORMS TO STAY
ACROSS THE INTERIOR AND TOWARDS THE GULF COAST. TEMPERATURES WILL
BE WARM...WITH HIGHS IN THE MID 80S TO LOWER 90S. THE EASTERLY LOW
LEVEL FLOW WILL KEEP OVERNIGHT TEMPS WARM IN THE MID 60S TO THE
MID 70S. A FEW SHOWERS MAY DEVELOP OVERNIGHT ACROSS THE ATLANTIC
WATERS...AND MOVE TOWARDS THE EAST COAST.
ANOTHER UPPER LOW WILL MOVE SOUTHEAST ACROSS THE UPPER GREAT LAKES
ON SATURDAY...WITH THE TROUGH DIGGING INTO THE SOUTHEAST. THIS WILL
ALLOW LOW PRESSURE OVER THE NORTHEAST TO DEEPEN...AND A COLD FRONT
EXTENDING FROM THE LOW WILL PUSH INTO THE SOUTHEAST. DEEPER MOISTURE
WILL BEGIN TO POOL SOUTH OF THIS BOUNDARY OVER SOUTHERN GEORGIA AND
NORTHERN FLORIDA. THE UPPER RIDGE WILL FLATTEN AND PUSH SOUTH...AND
THIS SHOULD ALLOW FOR A LITTLE MORE ACTIVITY ALONG THE SEA BREEZE
BOUNDARIES ACROSS THE INTERIOR. SLOW STORM MOTION IS EXPECTED ONCE
AGAIN.
THE FRONTAL BOUNDARY WILL MOVE INTO NORTH AND CENTRAL FLORIDA ON
SUNDAY...AND SURFACE WINDS WILL SHIFT MORE TO THE SOUTH...WITH
SOUTHWEST TO WESTERLY FLOW ABOVE THE SURFACE. THE DRY AIR WILL
REMAIN IN THE LOW/MID LEVELS...SO POP GUIDANCE REMAINS LOW. THE
SURFACE BOUNDARY WILL MOVE INTO SOUTH FLORIDA OVERNIGHT SUNDAY INTO
MONDAY MORNING...WITH THE MOISTURE BOUNDARY LAGGING BEHIND INTO
CENTRAL FLORIDA. THE SURFACE FRONT WILL MOVE THROUGH THE REGION BY
EARLY AFTERNOON...WITH THE MOISTURE SCOURING OUT FROM NORTH TO SOUTH
BEGINNING MID/LATE AFTERNOON. SO RAIN CHANCES SHOULD BE CONFINED TO
THE SOUTHEASTERN HALF OF THE REGION...IF THE MOISTURE HANGS AROUND
AS THE MODELS INDICATE.
HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST ON TUESDAY...WITH DRIER
AIR AND NORTHEASTERLY FLOW. HIGH PRESSURE WILL THEN REMAIN IN
CONTROL OF THE WEATHER THROUGH THE END OF THE FORECAST PERIOD...WITH
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. WITH MODERATE
NORTHEASTERLY FLOW TUESDAY AND WEDNESDAY...THERE WILL A HIGHER
THREAT FOR RIP CURRENTS ALONG THE ATLANTIC BEACHES.
MARINE...
LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
NIGHT INTO TUESDAY. WINDS WILL INCREASE OUT OF THE
NORTHEAST...WITH DETERIORATING MARINE CONDITIONS.
FIRE WEATHER...
MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 73 86 74 / 10 10 20 20
FORT LAUDERDALE 86 76 86 76 / 20 10 10 10
MIAMI 87 76 88 75 / 20 10 10 10
NAPLES 87 71 86 71 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
746 AM EDT FRI MAY 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS OUR AREA TODAY BRINGING MORE RAIN
SHOWERS AND POSSIBLE THUNDERSTORMS. IN THE WAKE OF THIS STORM
SYSTEM...PROGRESSIVELY COOLER AIR WILL FLOOD ACROSS THE REGION THIS
WEEKEND...WITH TEMPERATURES FALLING BACK TO WELL BELOW NORMAL LEVELS
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAIN SHOWERS ARE ON THEIR WAY TOWARD WESTERN NEW YORK THIS MORNING
AS A STORM SYSTEM WILL SHIFT EAST ACROSS OUR REGION DURING THE
COURSE OF THE DAY. THE CENTER OF THE SURFACE LOW IS LOCATED NEAR
SOUTHERN MICHIGAN AND WILL TRACK TO THE EAST-NORTHEAST ACROSS
LAKE ERIE THIS AFTERNOON THEN RUNNING JUST NORTH OF LAKE ONTARIO
TONIGHT. CURRENT KBUF RADAR SHOWING LEADING BAND OF RAIN SHOWERS IS
JUST ABOUT TO WORK INTO CHAUTAUQUA COUNTY. OTHERWISE VISIBLE SATELLITE
IS SHOWING HIGH AND MID LEVEL CLOUDS SPREADING EAST ACROSS WESTERN
NEW YORK AHEAD OF THE SYSTEM WITH LOW CLOUDS AND FOG FOUND ACROSS
THE EASTERN LAKE ONTARIO REGION AND THROUGH THE VALLEYS OF THE TWIN
TIERS.
MODEL GUIDANCE INCLUDING LATEST HRRR SHOWS RAIN SHOWERS WILL
ARRIVE ACROSS THE SOUTHERN TIER BETWEEN 12-14Z THE NIAGARA FRONTIER
14-17Z AND THEN ROCHESTER ON EASTWARD THROUGH THE AFTERNOON HOURS.
LATER THIS AFTERNOON THE NAM MODEL SHOWS SOME WEAK INSTABILITY WITH
MLCAPES OF UP TO 500 J/KG...HAVE LEFT CHANCE FOR THUNDERSTORMS IN
THE FORECAST. ADDITIONAL FORCING FOR TODAYS WEATHER IS PROVIDED BY
30-40 KNOT LOW LEVEL JET WHICH MAY MIX DOWN SOME TOWARD THE SURFACE
DURING THE DAY BRINGING SOME WIND GUSTS TO 20-30 MPH RANGE.
DURING THE AFTERNOON HOURS SOME AREAS COULD SEE A BREAK IN SHOWER
ACTIVITY BEFORE A COLD FRONT BRINGS ADDITIONAL RAIN SHOWERS LATER
THIS EVENING. THE COLD FRONT WILL LIKELY CROSS THE FORECAST AREA
BETWEEN MIDNIGHT AND EARLY MORNING WITH CHANCES FOR RAIN SHOWERS
RAPIDLY LOWERING ON ITS HEELS. RAINFALL AMOUNTS WILL RUN BETWEEN A
HALF AND ONE INCH USING BLEND OF SREF AND WPC GUIDANCE WHICH SEEMS
REASONABLE WITH MOIST GREATER THAN ONE INCH PWAT AIRMASS SHIFTING
OVER THE FORECAST AREA AHEAD OF THE SURFACE LOW. ANOTHER DAY OF MILD
TEMPERATURES BUT READING WILL BE CLOSER TO NORMAL. HIGHS WILL RUN IN
THE UPPER 60S TO LOW 70S. LOWS TONIGHT WILL FALL INTO THE UPPER 40S
ACROSS WNY BUT MAY REMAIN IN THE MID 50S OR SO ACROSS CNY AS COLD
FRONT ARRIVES LATER IN THE NIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE SURFACE LOW RESPONSIBLE FOR FRIDAY AND FRIDAY NIGHT/S RAINFALL
WILL BE LIFTING OUT OF THE REGION AND DOWN THE SAINT LAWRENCE VALLEY
ON SATURDAY. THE DEEPEST MOISTURE AND HEAVIEST SHOWERS ASSOCIATED WITH
THIS SYSTEM SHOULD BE PUSHING OUT OF THE NORTH COUNTRY SATURDAY
MORNING...HOWEVER SCATTERED SHOWERS ARE EXPECTED LINGER THROUGH THE
MORNING HOURS ACROSS MUCH OF THE FORECAST AREA AS AN UPPER LEVEL
VORTMAX TRACKS ACROSS WESTERN AND UPSTATE NEW YORK. EXPECT SHOWERS
TO TAPER OFF FROM WEST TO EAST BY THE AFTERNOON AS COOLER AND DRIER
AIR MAKES ITS WAY INTO THE LOWER GREAT LAKES. LOOK FOR TEMEPRATURES
TO DROP BACK BELOW NORMAL AS THIS COOLER AIR FILTERS INTO THE REGION
WITH HIGHS IN THE UPPER 50S TO LOWER 60S...THOUGH TYPICALLY WARMER
SPOTS IN THE GENESEE VALLEY AND FINGER LAKES SHOULD MANAGE TO REACH
THE MID 60S.
LOOK FOR A MUCH MORE SIGNIFICANT DROP IN TEMEPETAURES TO OCCUR
SATURDAY NIGHT AS A POTENT UPPER LEVEL LOW DROPS INTO THE GREAT
LAKES FROM WESTERN ONTARIO...PUSHING A SHARP COLD FRONT ACROSS THE
LOWER GREAT LAKES AHEAD OF IT. EXPECT TERMERPATURES TO DROP INTO THE
UPPER 30S ACROSS WESTERN NEW YORK AND THE SOUITHERN TIER SATURDAY
NIGHT AS MUCH COLDER AND DRIER AIR ADVECTS INTO THE EMPIRE STATE.
ONSHORE FLOW AND A LATER TIMING OF THE FRONTAL PASSAGE OVERNIGHT
SHOULD KEEP THE NORTH COUNTRY AND AREAS NEAR LAKE ONTARIO IN THE
40S. LIMITED MOISTURE MEANS THAT ANY SHOWER ACTVITY
ACCOMPANYING THE FRONTAL PASSAGE SHOULD BE LIMITED TO JUST A FEW
LIGHT SHOWERS AT BEST.
SUNDAY WILL BE COLD AND BLUSTERY AS THE AFORMENTIONED UPPER LEVEL
TRACKS INTO QUEBEC WHILE THE UPPER LEVEL TROUGH AXIS SWINGS ACROSS
THE LOWER GREAT LAKES. WELL ALIGNED WESTERLY FLOW COUPLED WITH
FAIRLY STEEP LOW LEVEL LAPSE RATES THANKS TO THE STRONG COLD
ADVECTION ALOFT WILL ALLOW FOR GOOD MIXING IN THE BOUNDARY
LAYER...RESULTING IN GUSTS OF 25 TO 40 MPH ACROSS MCUH OF THE
FORECAST AREA...PARTICULARLY DOWNWIND OF THE LAKES WHERE GALE FORCE
GUSTS WILL BE POSSIBLE. THE WINDY CONDITIONS WILL SERVE TO FURTHER
EMPHASIZE THE CHILL AS HIGHS ARE ONLY EXPECTED TO REACH THE UPPER
40S TO LOWER 50S WITH WIND CHILLS IN THE 30S. IN ADDITION THE
INSTABILITY INDUCED BY THE COLD ADVECTION ALOFT WILL YIELD PLENTY OF
CLOUD COVER ACROSS THE AREA ALONG WITH A POTENTIAL FOR SCATTERED
RAIN SHOWERS IN THE AFTERNOON.
THE CHILL WILL CONTINUE INTO SUNDAY NIGHT AS THE UPPER LEVEL TROUGH
AND THE CORE OF THE COLD AIR ALOFT CROSSES NEW YORK STATE AS 850MB
TEMPS DROP BELOW -6C. OVERNIGHT LOWS NEAR THE LAKES WILL DROP INTO
THE MID 30S WHILE FARTHER INLAND A HARD FREEZE WILL BE POSSIBLE
ACROSS THE SOUTHERN TIER AS LOWS BOTTOM OUT IN THE UPPER 20S. THE
COMBINATION OF CONTINUED WESTERLY FLOW ACROSS THE LAKES ALONG WITH
THE COLD AIR ALOFT COULD GENERATE LAKE EFFECT
PRECIPITATION...PARTICULARLY EAST OF LAKE ONTARIO WHERE SFC-850MB
DELTA-T VALUES WILL DROP TO -14C. HAVE BUMPED POPS UP TO LIKELY
ACROSS THE NORTH COUTNRY AND GIVEN THAT TEMPS WILL DROP INTO THE MID
30S THERE...WE COULD SEE A RAIN/SNOW MIX ACROSS THE TUG HILL PLATEAU.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE RETURN TO MORE ACTIVE WEATHER WILL CONTINUE THROUGH THE LONG
TERM NOW THAT THE PERSISTENT BLOCKING PATTERN HAS BEEN BROKEN
DOWN...TO BE REPLACED BY A MORE ZONAL FLOW ALONG THE US/CANADIAN
BORDER.
THE UPPER LEVEL TROUGH THAT BROUGHT THE COOL DOWN OVER THE WEEKEND
WILL CONTINUE TO IMPACT THE REGION MONDAY. AS A RESULT HIGHS ON
MONDAY WILL ONLY BE IN THE LOWER TO MID 50S AT BEST...WITH UPPER 40S
ACROSS HIGHER TERRAIN. TEMPS WILL GET COLD ENOUGH MONDAY NIGHT TO
BRING THE POTENTIAL FOR FROST INLAND FROM THE IMMEDIATE LAKESHORES.
THE TROUGH WILL QUICKLY PULL AWAY MONDAY NIGHT AND TUESDAY MORNING
WITH A RETURN TO DRY WEATHER. A WARM FRONT WILL THEN CROSS THE
REGION ON TUESDAY. MODEL GUIDANCE HAS BEEN WAVERING BETWEEN A MAINLY
DRY WARM FRONT OR BETTER SHOWER CHANCES. FOR NOW WILL STICK WITH
PREVIOUS FORECAST CONTINUITY AND KEEP TUESDAY MAINLY DRY.
FROM WEDNESDAY INTO THURSDAY A MUCH WARMER AIRMASS WILL PUSH QUICKLY
EAST ACROSS THE NATION AND INTO OUR REGION AS THE PATTERN REMAINS
PROGRESSIVE AND BEGINS TO DE-AMPLIFY. EXPECT TEMPS TO SOAR TO WELL
ABOVE AVERAGE AGAIN. UNLIKE THE LAST WARM STRETCH...A FRONTAL ZONE
AND MORE ACTIVE FLOW ALOFT WILL BE NEARBY. THIS WILL BRING CHANCES
OF SHOWERS AND EVEN A FEW THUNDERSTORMS TO THE REGION ALONG WITH A
SOMEWHAT MUGGIER AIRMASS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS ALL OF WESTERN NEW YORK THIS
MORNING WITH SHOWERS ARRIVING AT WESTERN NY TERMINALS BEFORE NOON.
EAST OF LAKE ONTARIO SOME MVFR/IFR LOW CLOUDS AND FOG IS BEING
REPORTED AT KFZY/KART/KGTB. THIS SHOULD ERODE BY 14-15Z.
ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE OHIO VALLEY WITH
THICKENING CLOUDS ALREADY ARRIVING ACROSS WNY AT 12Z. RAIN SHOWERS
WILL ARRIVING ACROSS THE REGION FROM WEST TO EAST THROUGH THE DAY.
TAFS INCLUDE -SHRA TIMING BASED ON LATEST HRRR GUIDANCE. A CHANCE OF
A FEW THUNDERSTORMS MAY ALSO BECOME POSSIBLE AS SOME WEAK TO MODEST
INSTABILITY REDEVELOPS IN THE AFTERNOON BUT HAVE LEFT OUT OF THE
TAFS DUE TO LOWER CONFIDENCE AT ANY PARTICULAR SITE. TERMINALS WILL
LOWER BACK TO MVFR/IFR LATER THIS EVENING JUST AHEAD OF AND RIGHT
BEHIND THE SYSTEMS COLD FRONT WHICH SHOULD CROSS THE REGION 06-12Z.
OUTLOOK...
SATURDAY...SHOWERS TAPERING OFF WITH IMPROVEMENT BACK TO MVFR/VFR.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS
BOTH DAYS.
TUESDAY...VFR.
&&
.MARINE...
ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE CENTRAL GREAT
LAKES TODAY AND BRING A RETURN OF MORE SHOWERS AND POSSIBLE
THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...THE PRESSURE GRADIENT ACROSS THE LOWER
LAKES WILL TIGHTEN A LITTLE TODAY. COUPLED WITH STABLE TEMPERATURE
PROFILES DUE TO WARM AIR OVER COOL LAKES...THIS WILL RESULT IN A
CONTINUATION OF RELATIVELY LIGHT WINDS AND MINIMAL WAVES
TONIGHT...BEFORE THESE INCREASE SOMEWHAT ON LAKE ONTARIO.
A PROGRESSIVELY STRONGER WESTERLY FLOW WILL SET UP ACROSS THE LOWER
LAKES REGION BEHIND THE SYSTEMS COLD FRONT GOING INTO THE
WEEKEND...WITH WINDS AND WAVES POSSIBLY INCREASING TO ADVISORY
LEVELS BY SUNDAY AND MAYBE EVEN GALE FORCE ON LAKE ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...HITCHCOCK/WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1036 AM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 1035 AM CDT FRI MAY 10 2013
THE MAIN IMPACTS FOR THE SHORT TERM UPDATE ARE GUSTY WINDS AND FIRE
DANGER.
A STRONG COLD FRONT CURRENTLY LOCATED NEAR MINOT WILL QUICKLY
BLAST SOUTH OUT OF NORTH DAKOTA BY LATE AFTERNOON. BEHIND THE
FRONT PRESSURE RISES NEAR 5 MB WITHIN THE LAST THREE HOURS WILL
DRIVE SUSTAINED WINDS NEAR 30 MPH AND FREQUENT GUSTS UP TO 45 MPH.
THEREFORE A WIND ADVISORY WAS ISSUED. THESE GUSTY WINDS AND VERY
DRY AIR WILL CONTINUE TO DRIVE DOWN RELATIVE HUMIDITIES AND FIRE
DANGER UP.
PRECIPITATION CHANCES WERE LOWERED FOR THIS UPDATE. LATEST GUIDANCE
FROM THE 13 UTC RAP AND 14 UTC HRRR SHOW VERY LITTLE PRECIPITATION
DEVELOPING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE
AFTERNOON HOURS. LATEST OBSERVATIONS SHOW VERY DRY AIR AT THE
SURFACE AND ONLY LIGHT RAIN SHOWER ECHOS SHOWING UP ON RADAR. BEST
CHANCE OF PRECIPITATION STILL LOOKS TO BE ACROSS FAR SOUTHERN
NORTH DAKOTA LATE THIS AFTERNOON AS PEAK HEATING WILL INCREASE
INSTABILITY AND PROXIMITY TO A MORE MOIST AIRMASS MAY PROVIDE ENOUGH
TO SPAWN SOME SCATTERED SHOWERS AND THUNDERSTORMS.
UPDATE ISSUED AT 652 AM CDT FRI MAY 10 2013
COLD FRONT EXTENDING SOUTHWEST FROM A SURFACE LOW NEAR LAKE
WINNIPEG WILL MOVE INTO NORTHWEST NORTH DAKOTA SHORTLY. INCREASING
CLOUDS AND A FEW SHOWERS SHOWING UP OVER SOUTHERN SASKATCHEWAN AND
MANITOBA. CURRENT FORECAST HAS A GOOD HANDLE ON CURRENT PLACEMENT
OF CLOUDS AND PRECIPITATION. ONLY CHANGES TO THE FORECAST WERE TO
UPDATE CURRENT SENSIBLE WEATHER ELEMENTS. THIS DROPPED OUR
OVERNIGHT LOWS SOME ACROSS CENTRAL NORTH DAKOTA WHERE CLEAR SKIES
AND LIGHT WINDS ALLOWED TEMPERATURES TO DROP A BIT BELOW FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT FRI MAY 10 2013
MAIN HIGHLIGHT FOR THE SHORT TERM WILL BE THE APPROACHING COLD FRONT
AND RESULTING WEATHER IMPACTS INCLUDING FIRE WEATHER CONCERNS.
CURRENTLY...WATER VAPOR SATELLITE IMAGERY INDICATES UPPER LEVEL
SHORTWAVE OVER SOUTHERN MANITOBA/SASKATCHEWAN MOVING SOUTHEASTWARD.
THIS FEATURE HANDLED WELL BY THE MODELS AND WILL USE A MODEL BLEND
FOR FORECAST DETAILS. SURFACE COLD FRONT ASSOCIATED WITH THE UPPER
LEVEL SHORTWAVE EXTENDED FROM NORTHERN LAKE WINNIPEG ACROSS SOUTHERN
SASKATCHEWAN TO NORTH CENTRAL MONTANA. AHEAD OF THE FRONT WINDS WERE
LIGHT AND FROM THE SOUTH.
THE COLD FRONT IS PROGGED TO REACH THE NORTHWEST CORNER OF THE STATE
AROUND SUNRISE AND CONTINUE MOVING SOUTHEASTWARD. BY AROUND NOON CDT
THE FRONT SHOULD BE APPROACHING DICKINSON/GARRISON/DEVILS LAKE AREA
AND REACH THE JAMESTOWN AREA BY MID-LATE AFTERNOON. AHEAD OF THE
FRONT THE SOUTH WINDS SHOULD BECOME MORE SOUTHWESTERLY AND BEGIN
INCREASING...THEN AFTER THE FRONT PASSES WINDS SHOULD BECOME
NORTHWEST AND INCREASE TO 20 TO 30 MPH. BUFKIT SOUNDINGS AND LOOKING
AT H850 FORECAST WINDS...THERE SHOULD BE GOOD LINKAGE ALOFT TO ABOVE
H800 AND WINDS AROUND H850 ARE AROUND 30 KNOTS. THUS SUSTAINED WINDS
SHOULD BE JUST SHY OF WIND ADVISORY CRITERIA OF 30 MPH FOR 3 HOURS
OR MORE. WIND GUSTS COULD BE AS HIGH AS 35 TO POSSIBLY 40 MPH IN
SOME LOCALES.
THESE STRONG WINDS COMBINED WITH DRY GRASSLANDS WILL RAISE FIRE
WEATHER CONCERNS. SEE THE FIRE WEATHER SECTION BELOW FOR DETAILS.
THE COLD FRONT IS PROGGED TO EXTEND ACROSS SOUTHERN NORTH DAKOTA
THIS AFTERNOON - DURING PEAK HEATING OF THE DAY. CAPE VALUES ARE
200-400 FOR THE MID AND LATE AFTERNOON/EARLY EVENING HOURS AND WILL
KEEP THE CHANCE OF RAIN SHOWERS NORTHWEST AND NORTH CENTRAL NORTH
DAKOTA THIS MORNING AND THUNDERSHOWERS SOUTHWEST AND SOUTH CENTRAL
THIS AFTERNOON. LOOKING AT HIGH TEMPERATURES FROM THE 60S NORTH TO
THE LOW TO MID 70S SOUTH.
WINDS SHOULD DECREASE DURING THE EVENING WITH COOL AND DRY AIR
PUSHING INTO THE STATE. LOWS TONIGHT SHOULD DIP INTO THE 20S TO
LOWER 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 410 AM CDT FRI MAY 10 2013
WE BEGIN THE EXTENDED PERIOD ON THE COOL SIDE WITH CANADIAN HIGH
PRESSURE OVER THE REGION SATURDAY MORNING. STRONG UPPER LEVEL
RIDGING OVER THE WESTERN U.S. SATURDAY WILL TRANSLATE EAST THROUGH
THE WEEKEND BRINGING WARMER TEMPERATURES TO WESTERN NORTH DAKOTA ON
SUNDAY. DRY CONDITIONS ARE EXPECTED SATURDAY THROUGH SUNDAY.
A WEAK SURFACE TROUGH MOVES INTO THE AREA SUNDAY NIGHT...ASSOCIATED
WITH A NORTHERN STREAM WAVE THAT FLATTENS THE UPPER RIDGE THAT HAS
MOVED OVER THE NORTHERN PLAINS. MODELS ARE DEPICTING VERY LIGHT QPF
ALONG THE TROUGH BUT WITH ABUNDANT DRY AIR OVER THE REGION...WILL
HOLD OFF ON INTRODUCING A MENTION OF SHOWERS AT THIS TIME.
UPPER RIDGE BUILDS BACK ON MONDAY BEHIND THE SURFACE TROUGH AND IN
RESPONSE TO A WAVE MOVING ONTO THE NORTHWESTERN U.S. COAST. THIS
SHOULD SET THE STAGE FOR AN UNSEASONABLY WARM MONDAY WITH NEAR
RECORD HIGH TEMPERATURES OVER THE SOUTHWEST AND SOUTH CENTRAL.
RECORD HIGH FOR BISMARCK MONDAY IS 91 DEGREES...WITH A FORECAST HIGH
OF 89. OTHER FIRST ORDER STATION HIGHS ARE IN THE MID 90S AND WOULD
BE HARDER TO REACH.
THE UPPER RIDGE BREAKS DOWN MONDAY NIGHT AS THE NORTHWEST U.S.
TROUGH MOVES INTO THE NORTHERN ROCKIES AND A QUASI-ZONAL FLOW TAKES
SHAPE MONDAY NIGHT THROUGH THURSDAY. TEMPERATURES AFTER MONDAY WILL
RETURN TO NORMAL...AROUND 70 DEGREES FOR HIGHS. WITH A PROGRESSIVE
WESTERLY FLOW...PRECIPITATION CHANCES CANNOT BE RULED OUT OF
PRETTY MUCH ANY PERIOD FROM MONDAY NIGHT THROUGH THURSDAY. ALTHOUGH
ANY SHOWERS OR THUNDERSTORMS WOULD LIKELY BE SPOTTY. UTILIZED A
MODEL BLEND WITH PERSISTENCE FOR POPS WHICH PRETTY MUCH GIVES SLIGHT
CHANCE POPS THROUGH THE PERIOD. UNFORTUNATELY WITH MODEL TIMING AND
PLACEMENT DIFFERENCES IN THIS PROGRESSIVE FLOW ITS TOO HARD AT
THIS TIME TO TRY AND NAIL DOWN A SPECIFIC PERIOD FOR
PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 652 AM CDT FRI MAY 10 2013
A STRONG COLD FRONT HAS ENTERED NORTHWESTERN NORTH DAKOTA. THE
FRONT IS FORECAST TO MOVE THROUGH KISN...KMOT AND KDIK BETWEEN
15-18 UTC...KBIS BY 19-20 UTC AND KJMS BY 20-22 UTC. STRONG
NORTHWEST WINDS WITH GUSTS OF 35-45 KTS ARE EXPECTED BEHIND THE
FRONT. ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM ACTIVITY IS
ALSO POSSIBLE NEAR THE FRONT AT KDIK...KBIS AND KJMS...WITH THE
TERMINAL MOST LIKELY TO BE IMPACTED BEING KJMS.
&&
.FIRE WEATHER...
ISSUED AT 410 AM CDT FRI MAY 10 2013
THE FIRE WEATHER WATCH THAT WAS IN EFFECT FOR PORTIONS OF
NORTHWEST...NORTH CENTRAL...AND SOUTHWESTERN NORTH DAKOTA WILL BE
UPGRADED TO A RED FLAG WARNING. EXPECT DEWPOINTS TO RISE WITH THE
APPROACH OF THE COLD FRONT...THEN DROP INTO THE 20S BEHIND IT. WENT
WITH THESE LOWER DEWPOINTS THAN MODELS/GUIDANCE WOULD SUGGEST.
EXPECT THE SURFACE/BOUNDARY LAYER WILL MIX WELL UP TO H800 AND
LOWER DEWPOINTS THIS AFTERNOON. MINIMUM RELATIVE HUMIDITY VALUES
ARE EXPECTED TO BE AROUND 20 TO 25 PERCENT FOR MUCH OF WESTERN AND
PARTS OF CENTRAL NORTH DAKOTA. EXPECT AFTERNOON NORTHWEST WINDS OF
25 TO 30 MPH COMBINED WITH THE LOW RELATIVE HUMIDITY AND VERY DRY
PASTURES WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS. THESE
CONDITIONS WOULD SUPPORT RAPID FIRE SPREAD SHOULD A FIRE IGNITE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>003-009>011-017>019-021-031>033.
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>005-009>013-017>023-031>035-040>046.
&&
$$
UPDATE...AJ
SHORT TERM...JV
LONG TERM...TWH
AVIATION...JV
FIRE WEATHER...JV
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
654 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
TODAY APPEARS A LITTLE QUIETER THEN THE PAST FEW DAYS...AS OUR
STUBBORN UPPER LEVEL LOW IS FINALLY OOZING EAST OF OUR AREA. STILL
HAVE AREAS OF CLOUD COVER TO CONTEND WITH EARLY TODAY. HOWEVER
MOISTURE PROFILES ARE SUCH THAT THERE SHOULD BE A GENERAL CLEARING
THROUGH THE DAY OTHER THEN SOME STRATO CUMULUS POTENTIAL OVER PARTS
OF THE FORECAST AREA WHICH RECEIVED A GOOD WETTING RAINFALL THE PAST
FEW DAYS. BUT AS THE AFTERNOON PROGRESSES...ANY STRATO CUMULUS
POTENTIAL SHOULD DRY UP. WINDS LOOK TO BE FAIRLY LIGHT AHEAD OF
TONIGHTS COLD FRONT. THIS WILL KEEP MIXING POTENTIAL DOWN A BIT...
SO KEPT HIGHS A FEW DEGREES EITHER SIDE OF SEASONAL NORMALS. ONE
THING TO WATCH FOR ARE DEW POINT TEMPERATURES IN OUR FAR WESTERN
ZONES. GUIDANCE DEW POINT VALUES HAVE BEEN CONSISTENTLY TOO HIGH IN
OUR CENTRAL SD ZONES FOR DAYS NOW. DEW POINT READINGS SHOULD RAISE
EARLY TODAY. HOWEVER ONCE THE SURFACE WINDS GO WESTERLY THIS
AFTERNOON AHEAD OF THE COLD FRONT...NOT SURE WHY LOCATIONS AROUND
CHAMBERLAIN WOULD HAVE DEW POINTS IN THE LOWER 40S AS SUGGESTED BY
SOME GUIDANCES. RAP AND HRRR LOOK TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION IN THAT AREA...AND DO INDEED DRY OUT OUR FAR
WESTERN ZONES THIS AFTERNOON. THEREFORE BLENDED THOSE TWO MODELS
INTO SOME OF THE MORE REASONABLE LOOKING CONSENSUS READINGS TO GIVE
DRIER MINIMUM HUMIDITY VALUES IN CENTRAL SD. CONCERNING
PRECIPITATION...AT THE MOMENT IT LOOKS DRY. HOWEVER RIGHT ALONG A
SUBTLE SURFACE CONVERGENCE AXIS WEST OF I 29...MAY NEED TO WATCH FOR
A FEW SPRINKLES OR AN ISOLATED LIGHT SHOWER EARLY TODAY IN THOSE
LOCATIONS.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
COLD FRONT PROGGED TO CROSS THE CWA TONIGHT...ENTERING THE
NORTHWEST PORTION OF OUR CWA BY 03Z AND EXITING NORTHWEST IOWA BY
09Z. BEST LARGE SCALE FORCING AND DEEPER MOISTURE STAYS OFF TO OUR
NORTHEAST. THUS THE GREATEST PRECIP POTENTIAL SHOULD BE NORTHEAST OF
US OVER MINNESOTA...WITH OUR AREA HAVING TO RELY ON ANY CONVECTION
THAT CAN GET GOING. HOWEVER IT IS A DECENT FRONTAL BOUNDARY...WITH
POTENTIALLY JUST ENOUGH LOW TO MID LEVEL THETAE ADVECTION TO INDEED
KICK OFF A FEW SHOWERS...THUS WILL KEEP THE LOW POPS GOING. JUST
ENOUGH INSTABILITY TO MAYBE GET A FEW RUMBLES OF THUNDER AS WELL.
DECENT LOW LEVEL JET OF WINDS BEHIND THE FRONT WITH A QUICK SHOT OF
CAA AS WELL. THUS NOT SURPRISING THAT MODEL SOUNDINGS SHOW THE
OPPORTUNITY FOR A PERIOD OF GUSTY WINDS RIGHT BEHIND THE FRONT
TONIGHT. MAY BE ABLE TO GET SOME 40 MPH GUSTS DOWN TO THE SURFACE
FOR A FEW HOURS FOLLOWING THE FRONTAL BOUNDARY AS WE MIX INTO THE 30
TO 40 KT JET. SO SOMETHING TO KEEP AN EYE ON.
EXPECT WINDS TO DROP OFF SOME SATURDAY MORNING AS MIXING WEAKENS A
BIT AND THE JET PUSHES SOUTHEAST OF THE AREA. HOWEVER AS DEEPER
MIXING BEGINS WITH DAYTIME HEATING WINDS WILL ONCE AGAIN INCREASE.
NORTHERLY WINDS GUSTING 25 TO 35 MPH LOOK LIKELY FROM MID MORNING
INTO THE AFTERNOON HOURS. IT WILL BE A CHILLY ONE TOO...WITH HIGHS
RANGING FROM THE LOW 50S OVER SOUTHWEST MINNESOTA TO AROUND 60 ALONG
THE MISSOURI RIVER. SHOULD AT LEAST BE MOSTLY SUNNY THOUGH...WITH
JUST A FEW AFTERNOON FAIR WEATHER CU. SURFACE HIGH PRESSURE QUICKLY
BUILDS IN SATURDAY NIGHT...WITH IDEAL RADIATIONAL COOLING EXPECTED
OVER MOST OF THE CWA. GIVEN THE COOL LOW LEVEL TEMPERATURE PROFILES
IN PLACE...EXPECTING A COLD NIGHT. WENT AT OR BELOW THE COLDEST
GUIDANCE...WITH UPPER 20S TO LOW 30S OVER MOST OF THE AREA. HOWEVER
IF CURRENT TRENDS PERSIST...WOULD NOT BE SURPRISED TO SEE SOME MID
20S IN SOME OF THE COOLER LOCATIONS EAST OF THE JAMES RIVER.
NEEDLESS TO SAY...LOOKS LIKE FROST OR FREEZE HEADLINES WILL BE
NEEDED FOR MOST OF THE CWA.
THE TROUGH EXITS TO OUR EAST ON SUNDAY...ALLOWING FOR A SLOW WARMUP
TO BEGIN. HIGHS WILL STILL BE BELOW NORMAL THOUGH...WITH UPPER 50S
AND LOW 60S EAST AND UPPER 60S WEST. WINDS WILL BE PRETTY LIGHT AND
THE SUN SHOULD BE SHINING BRIGHT...THUS NOT A BAD DAY OVERALL. OUR
REAL WARMTH BEGINS TO MOVE IN MONDAY AS UPPER RIDGING BUILDS IN.
HIGHS MONDAY A BIT TRICKY...WITH A SHARP GRADIENT LIKELY. AROUND 90
SEEMS ALMOST CERTAIN IN SOUTH CENTRAL SOUTH DAKOTA THOUGH...WITH THE
GREATER UNCERTAINTY TO THE EAST. MODELS BOUNCING AROUND A BIT ON HOW
QUICKLY WARM AIR MOVES IN EAST OF THE JAMES...BUT MID 70S TO MID 80S
LOOK PROBABLE. TUESDAY SHOULD BE THE HOTTEST DAY OF THE YEAR THUS
FAR. MODELS HAVE SLOWED DOWN THE WEAK FRONT...MEANING WE SHOULD GET
THE FULL FORCE OF THE HEAT. 850MB TEMPERATURES ARE QUITE
IMPRESSIVE...RUNNING CLOSE TO THE CLIMATOLOGICAL MAX FOR THIS TIME
OF YEAR. WENT WELL ABOVE ALLBLEND FOR HIGHS...WITH UPPER 80S TO LOW
90S LOOKING LIKE A GOOD BET FOR THE ENTIRE CWA. HOWEVER...IT SEEMS
QUITE POSSIBLE THAT AN AREA OF MID TO UPPER 90S WILL OCCUR IN A
CORRIDOR JUST AHEAD OF THE FRONT. TRYING TO PIN DOWN WHERE THIS WILL
OCCUR IS TOUGH THIS FAR OUT...AS IT COULD REALISTICALLY BE AS FAR
WEST AS CENTRAL SOUTH DAKOTA...OR AS SOUTHEAST AS NORTHWEST IOWA.
THUS DID NOT WANT TO GO TOO HIGH WITH FORECAST MAXES THIS FAR
OUT...GIVEN THE CURRENT FORECAST IS ALREADY 20 DEGREES ABOVE NORMAL.
MODELS DIVERGE A BIT AFTER TUESDAY...BUT GENERAL CONSENSUS IS FOR
THE RIDGE TO FLATTEN AS WAVES TO OUR NORTH PUSH A FRONTAL BOUNDARY
SOUTH THROUGH THE NORTHERN PLAINS. STRENGTH OF THIS BOUNDARY STILL
UNCERTAIN...BUT EITHER WAY IT SHOULD BE COOLER WEDNESDAY AND
THURSDAY...WITH HIGHS EITHER IN THE 70S OR 80S DEPENDING ON FRONTAL
STRENGTH. PRECIP CHANCES TOUGH TO PIN DOWN...OTHER THAN THAT IT
LOOKS LIKE THERE GOOD BE SOME ISOLATED TO SCATTERED CONVECTION
ANYTIME TUESDAY NIGHT ON AS THE WEAK WAVES AND FRONTS PUSH
ACROSS...BUT NOT EXPECTING ANYTHING WIDESPREAD OR SIGNIFICANT AT
THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 652 AM CDT FRI MAY 10 2013
SOME LOCALIZED UPPER END IFR TO LOWER END MVFR CEILINGS WILL BE
PREVALENT IN THE MISSOURI RIVER VALLEY EARLY THIS MORNING.
OTHERWISE THE CURRENT CLOUD COVER WEST OF INTERSTATE 29 IS VFR. BY
LATE MORNING AND AFTERNOON...ALL LOCATIONS WILL BE VFR...WITH THAT
CONTINUING INTO TONIGHT. ONE OF THE MAIN AVIATION FEATURES
CONCERNS TONIGHT IN THAT A STRONG COLD FRONT WILL BE MOVING
THROUGH OUR FORECAST AREA. A FEW SHOWERS OR THUNDERSTORMS ARE
POSSIBLE ALONG THE FRONTAL PASSAGE. HOWEVER THE BIGGER CONCERN
WILL LIKELY BE WIND SPEEDS. AS WINDS SHIFT TO THE NORTH...WINDS
WILL LIKELY GUST BETWEEN 35 AND 40 KNOTS FOR A COUPLE OF HOURS
BEHIND THE FRONTAL PASSAGE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJF
LONG TERM...CHENARD
AVIATION...MJF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
614 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CDT FRI MAY 10 2013
MAIN FORECAST CONCERN IS WITH THE IMPACTS OF A COLD FRONT TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST INTO BRITISH COLUMBIA...A POTENT
SHORTWAVE TROUGH DROPPING INTO CENTRAL SASKATCHEWAN...AND A WEAK
SHORTWAVE TROUGH OVER CENTRAL WISCONSIN. THE LATTER SHORTWAVE TROUGH
WAS RESPONSIBLE FOR THE WET WEATHER YESTERDAY...WHICH LATEST RADAR
IMAGERY STILL SHOWS SCATTERED SHOWERS AND DRIZZLE OVER THE SOUTHEAST
HALF OF THE FORECAST AREA. CLOUDS ASSOCIATED WITH THE SHORTWAVE
ENCOMPASS MUCH OF THE FORECAST AREA...BUT HAVE CLEARED OUT ACROSS
NORTH DAKOTA INTO THE NORTHERN 2/3 OF MINNESOTA AND NORTHWEST WI.
00Z BIS AND ABR SOUNDINGS WERE VERY DRY BELOW 700MB WITH DEWPOINT
DEPRESSIONS OF 15C OR GREATER. THIS DRY AIR WAS ASSOCIATED WITH A
SURFACE RIDGE OF HIGH PRESSURE. A TIGHT PRESSURE GRADIENT AHEAD OF
THE HIGH AND LOW PRESSURE MOVING THROUGH NORTHERN ILLINOIS HAS
RESULTED IN SOME GUSTY NORTHEAST WINDS ACROSS THE FORECAST AREA.
COOLER AIR TOO WITH THE HIGH PRESSURE RIDGE...REFLECTED BY 850MB
TEMPS AT 00Z OF 5-7C FROM BIS TO MPX...COMPARED TO 10C AT DVN. TO
THE NORTHWEST...BEHIND THE POTENT SHORTWAVE TROUGH...MUCH COLDER
AIR EXISTS. -2C 850MB TEMPS WERE OBSERVED AT 00Z OVER NORTHERN
ALBERTA. THE COLD FRONT ASSOCIATED WITH THE TROUGH WAS IN SOUTHEAST
SASKATCHEWAN.
THE HIGH PRESSURE RIDGE AND ITS DRY AIR ARE FORECAST TO MOVE INTO
THE CWA THROUGH THE DAY...WITH THE RIDGE OVERHEAD AT 00Z. THUS...WE
WILL SEE GRADUAL CLEARING NORTHWEST TO SOUTHEAST THROUGH THE DAY.
MAY STILL HAVE TO CONTEND WITH SOME LINGERING SHOWERS TOO IN THE
SOUTHEAST SECTION OF THE FORECAST AREA UNTIL 15Z. TEMPERATURES ARE
LIKELY TO STRUGGLE TO RISE THIS MORNING WITH COLD ADVECTION AND
CLOUDS IN PLACE...BUT SHOULD BE ABLE TO CLIMB INTO THE LOW TO MID
60S BY LATE IN THE DAY WITH THE SUN AND 850MB TEMPS OF 4-5C.
MODELS ARE IN GOOD AGREEMENT TAKING THE POTENT SHORTWAVE TROUGH
OVER CENTRAL SASKATCHEWAN INTO NORTHWEST ONTARIO TONIGHT...WITH
ANOTHER STRONG SHORTWAVE DIGGING IN BEHIND IT INTO CENTRAL MINNESOTA
BY 12Z SATURDAY. THE 500MB HEIGHT FALLS ARE QUITE IMPRESSIVE BETWEEN
00-12Z...FROM AROUND 100 METERS ALONG I-90 TO ALMOST 200 METERS OVER
WESTERN LAKE SUPERIOR. NEEDLESS TO SAY...PLENTY OF DYNAMIC FORCING.
ONE HUGE PROBLEM IS THE LACK OF MOISTURE... ESPECIALLY AHEAD OF THE
TROUGH PER THE 00Z BIS SOUNDING. THUS...NO PRECIPITATION WILL OCCUR
AHEAD OF THE COLD FRONT ACCOMPANYING THE TROUGH...WHICH IS PROGGED
TO CROSS THE AREA BETWEEN 06-12Z. IF PRECIPITATION OCCURS...IT HAS
TO OCCUR THEN POST-FRONTAL...IN THE COOLER AIR. CROSS-SECTIONS SHOW
A FAIRLY STRONG LOW LEVEL FRONTOGENESIS-FRONTOLYSIS COUPLET...ALONG
WITH SOME NEGATIVE EPV BEING INGESTED INTO THIS CIRCULATION. WITH
ALL THE FORCING PRESENT...HAVE TO IMAGINE A NARROW BAND OF SHOWERS
COMING THROUGH BEHIND THE FRONT. THERE MAY EVEN BE A RUMBLE OR TWO
OF THUNDER GIVEN THE NEGATIVE EPV SIGNAL...BUT THE CHANCE AND
COVERAGE IS TOO LOW TO MENTION. EXPECT WINDS TOO TO RAPIDLY INCREASE
OUT OF THE NORTHWEST BEHIND THE FRONT...AIDED BY ISALLOBARIC
FORCING. SOME PLACES...LIKE ROCHESTER AND DODGE CENTER...COULD GUST
CLOSE TO WIND ADVISORY...ESPECIALLY WITH THE SHOWERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 327 AM CDT FRI MAY 10 2013
DEEP TROUGHING IS PROGGED TO PERSIST OVER THE GREAT LAKES MUCH OF
THE WEEKEND...RESULTING FROM THE POTENT SHORTWAVE TROUGH DIGGING
TOWARDS THE AREA TONIGHT. 500MB STANDARDIZED ANOMALIES ARE 1.5-2
BELOW NORMAL ALONG WITH 850MB ANOMALIES OF 2 BELOW NORMAL. THESE LOW
ANOMALIES RESULT IN A VARIETY OF ISSUES:
1. TEMPERATURES. CHILLY HIGHS AND LOWS ARE LIKELY...AND COULD GET
CLOSE TO RECORDS SOLELY BASED ON THE 850MB ANOMALIES. LA CROSSE
RECORD LOWS ARE AROUND 30 WHILE ROCHESTER IS AROUND 26. THE BIGGEST
PROBLEM WITH TEMPERATURES ARE THE WINDS. CONTINUOUS COLD ADVECTION
THROUGH SATURDAY NIGHT WILL HELP KEEP THE BOUNDARY LAYER MIXED...AND
WITH 925MB WINDS STILL AT 20-25 KT AT 12Z SUNDAY...EXPECTING
DIFFICULT CONDITIONS TO DECOUPLE. BETTER SHOT OF DECOUPLING TAKES
PLACE SUNDAY EVENING...BUT WARM ADVECTION TAKES HOLD AFTER
MIDNIGHT. FOR NOW HAVE TAKEN A BLEND OF MOS AND RAW MODEL GUIDANCE
FOR HIGHS AND LOWS...GIVEN THE UNCERTAINTY ON DECOUPLING.
2. WINDS...STRONG SUBSIDENCE FLOWS INTO THE AREA ON SATURDAY WILL
COMBINE WITH LOW LEVEL UNIDIRECTIONAL NORTHWEST FLOW...THE STRONG
MIXING FROM THE MAY SUN...AND COLD ADVECTION TO RESULT IN A BLUSTERY
DAY. WE COULD MIX TO 775 MB OR HIGHER. MOMENTUM TRANSFER OF THE
WINDS AT THAT LEVEL OF 40-45 KT RESULTS IN GUSTS OF 30-35 KT AT THE
SURFACE...JUST BELOW ADVISORY CRITERIA. WINDS SLOWLY DIMINISH
SATURDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE
PLAINS.
3. FROST/FREEZE. CONNECTING WITH THE TEMPERATURES AND WINDS ABOVE...
FROST LOOKS VERY DIFFICULT TO FORM SATURDAY NIGHT. ADDITIONALLY...
RELATIVE HUMIDITIES MAY NOT EXCEED 80 PERCENT DUE TO DRY ADVECTION.
IF ANYTHING...THE CONCERN WOULD COME FROM A FREEZE DUE TO THE
TEMPERATURES...IF THEY FALL BELOW FREEZING. BETTER SHOT OF FROST
WOULD COME SUNDAY NIGHT...DEPENDING ON WHEN HIGH CLOUDS AND THE WARM
AIR SPREADS IN. FROST LOOKS MOST LIKELY IN CENTRAL WISCONSIN.
4. PRECIPITATION...COLD POOL OF 500MB TEMPS OF -30C LOOKS TO CROSS
TAYLOR COUNTY MID-DAY SATURDAY. DAYTIME MIXING COMBINED WITH THE
MOISTURE WITH THIS COLD POOL COULD GENERATE A FEW SHOWERS ACROSS
TAYLOR/CLARK COUNTIES. HAVE KEPT 20 PERCENT CHANCES GOING FOR THESE.
OTHERWISE...DRY CONDITIONS EXPECTED TO PREVAIL.
FOR NEXT WEEK...THE BIG HIGHLIGHT IS TUESDAY AND WEDNESDAY WITH A
CONSISTENTLY SHOWN STRONG SURGE OF WARM AIR. THERE IS VERY STRONG
MODEL AGREEMENT OF TROUGHING COMING INTO THE PACIFIC NORTHWEST EARLY
NEXT WEEK...SHOVING A RIDGE TOWARDS THE FORECAST AREA. A LOW
POTENTIAL EXISTS FOR SOME SHOWERS AND THUNDERSTORMS AS THE RIDGE
APPROACHES MONDAY AFTERNOON INTO MONDAY NIGHT. HEADING INTO
TUESDAY...850MB STANDARDIZED ANOMALIES JUMP TO 2-2.5 ABOVE...
SUGGESTING POTENTIAL RECORD HIGHS. THERE ARE TWO ISSUES ON TUESDAY
TO CONTEND WITH...TIMING OF THE SURFACE WARM FRONT AND HOW DRY THE
AIR IS IN THE WAKE OF THE FRONT. THE 09.12Z/10.00Z GFS WERE IN GREAT
AGREEMENT PUSHING THE WARM FRONT THROUGH THE AREA ON TUESDAY...
LIKELY RESULTING IN HIGHS IN THE 80S TO POSSIBLY LOW 90S.
HOWEVER...THE 10.00Z ECMWF/CANADIAN ONLY GET THE WARM FRONT TO THE
MISSISSIPPI RIVER. WITH 850MB TEMPS OF 20C+ IN THE WAKE OF THE
FRONT...TIMING OF THE FRONT IS CRITICAL. ON THE MOISTURE SIDE...THE
GFS AND ECMWF WANT TO BRING DEWPOINTS UP INTO THE 60S...BUT THIS
SEEMS WAY TOO HIGH GIVEN THE LACK OF CORN CROPS TO THE SOUTH AND THE
WARM SURGE BEING OF ROCKIES ORIGIN. THUS...DEEPER MIXING IS LIKELY
BEHIND THE FRONT. NEXT CONCERN IS WHEN DOES A COLD FRONT COME
THROUGH. THE 10.00Z ECMWF/CANADIAN REALLY SLOWED THIS DOWN...NOT
CROSSING TIL THURSDAY. IF THIS COMES TRUE...HIGHS WEDNESDAY
COULD TOUCH 90. ON THE OTHER HAND...A FASTER FRONT FROM THE 10.00Z
GFS WOULD KEEP HIGHS IN THE 70S. SPLIT THE DIFFERENCE FOR HIGHS ON
WEDNESDAY FOR NOW. ALSO...MAINTAINED A 20-30 PERCENT CHANCE FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH THURSDAY FOR THE
FRONT...WITH WEDNESDAYS CHANCES IN CASE THE FRONT ENDS UP BEING
FASTER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 614 AM CDT FRI MAY 10 2013
RADAR SHOWING REMNANTS OF RAIN MOVING OFF TO THE SOUTHEAST WITH
MVFR/VFR CLOUD COVERING MUCH OF THE FORECAST AREA. CLOUDS WILL BE
ON A SLOW DIMINISHING TREND FROM NORTHWEST TO SOUTHEAST ACROSS THE
AREA AS HIGH PRESSURE BUILDS IN FROM ONTARIO AND MINNESOTA. BY
THIS EVENING...SKIES EXPECTED TO BE MOSTLY CLEAR WITH INCREASING
CLOUDS AGAIN AFTER MIDNIGHT AHEAD OF A COLD FRONT DROPPING INTO
THE REGION. SHOWERS ARE EXPECTED WITH THE FRONTAL PASSAGE WITH
CIGS FALLING INTO MVFR RANGE BY 10Z.
LOOKING FURTHER...GUSTY NORTHWEST WINDS WILL FOLLOW THE FRONTAL
PASSAGE SATURDAY. EXPECT WINDS IN THE 15 TO 25 KT RANGE WITH GUSTS
AROUND 35KT...ESPECIALLY ACROSS THE HIGHER/OPEN TERRAIN AREAS OF
SOUTHEAST MN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1113 AM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 848 AM MDT FRI MAY 10 2013
UPDATED FORECAST GRIDS AND ZONES TO REFLECT CURRENT CONDITIONS...WITH
GENERALLY CLEAR SKIES ACROSS THE CWA...AND A BAND OF MID LEVEL CLOUDS
MOVING SWD ACROSS THE PALMER DVD AND INTO N EL PASO. ALSO REDUCED
POPS AND TAPERED PRECIP CHANCES TOWARDS LATER THIS AFTERNOON. HRRR IDEA
OF BRINGING SCT SHOWERS ACROSS THE PLAINS BY MID TO LATE AFTERNOON LOOKS
REASONABLE...ALONG WITH BETTER COVERAGE ACROSS THE MTS. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI MAY 10 2013
THE UPPER TROF AXIS WILL CONTINUE TO SHIFT SOUTH OF THE AREA TODAY
WITH SOME TRAILING ENERGY ACROSS SRN WY/NRN CO SINKING ACROSS SE CO
DURING THE AFTERNOON. RESIDUAL MOISTURE COMBINED WITH THIS TRAILING
ENERGY FIRE OFF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ACROSS
THE MOUNTAINS DURING THE LATE MORNING WITH COVERAGE INCREASING
DURING THE AFTERNOON AS THEY SPREAD INTO THE ADJACENT VALLEYS AND
PORTIONS OF THE I-25 CORRIDOR. STEERING CURRENTS WILL BE MORE
NORTHERLY TODAY...WHICH SHOULD KEEP MAJORITY SHOWERS/TSTORMS OVER
THE MOUNTAINS. THE EXCEPTION TO THIS WILL BE ACROSS THE PALMER
DIVIDE WHERE SHORT RANGE MODELS INITIATE THUNDERSTORMS ACROSS THE
ELEVATED TERRAIN AND ALONG A WEAK WIND SHIFT BOUNDARY DURING THE
AFTERNOON. MODEL SOUNDINGS SHOW ONLY 100-200 J/KG OF CAPE ACROSS THE
MOUNTAINS AND LCLS LOOK HIGHER THAN PAST COUPLE DAYS...AROUND
625-650 MB. SO ALTHOUGH THE WALDO CANYON BURN SCAR WILL NEED TO BE
MONITORED CLOSELY FOR ANY STRONGER SHOWERS AND THUNDERSTORMS THAT
MIGHT DEVELOP...ESPECIALLY DUE TO THE SATURATED GROUND...THE CHANCES
THAT RAINFALL RATES WILL BE HIGH ENOUGH TO CAUSE A SIGNIFICANT
THREAT OF FLASH FLOODING LOOK LOW AT THIS POINT. THEREFORE WILL NOT
ISSUE ANY FLASH FLOOD WATCHES. HOWEVER THIS DOESN`T MEAN THE
POSSIBILITY DOESN`T EXIST AND THIS WILL NEED TO BE
MONITORED...ESPECIALLY IF DEW POINTS DON`T DROP OFF AS FAST AS
MODELS INDICATE.
CONVECTION DIES OFF QUICKLY DURING THE EVENING WITH ANOTHER
NORTHERLY SURGE DROPPING THROUGH THE SOUTHEAST PLAINS TOWARDS DAWN.
THIS MAY HELP HOLD TEMPERATURES UP A COUPLE DEGREES...KEEPING LOWS
IN THE LOWER 40S. OTHERWISE EXPECT CLEARING SKIES TOWARDS MORNING.
-KT
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI MAY 10 2013
NOT MUCH CHANGE TO THE FORECAST THINKING FOR THE EXTENDED. HIGH
PRESSURE WILL BUILD ACROSS THE GREAT BASIN ON SATURDAY WHILE A
STRONG LOW SPINS OVER EASTERN CANADA. THIS WILL PUT SOUTHERN
COLORADO UNDER NORTHWESTERLY FLOW ALOFT. MODELS INDICATING A WEAK
DISTURBANCE MOVING THROUGH THE FLOW. THIS DISTURBANCE COMBINED
WITH RESIDUAL MOISTURE FROM RECENT RAINFALL WILL LIKELY PRODUCE AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS AND
PALMER DIVIDE. LIGHTNING AND GUSTY OUTFLOW WINDS WILL LIKELY BE
THE PRIMARY THREATS. GIVEN THE CONVECTIVE NATURE...ANY SHOWERS OR
THUNDERSTORMS THAT DEVELOP OVER THE WALDO CANYON BURN SCAR COULD
PRODUCE LOCALLY HEAVY RAINFALL AND POSSIBLE FLASH FLOODING.
AFTERNOON HIGHS WILL REMAIN IN THE UPPER 60S TO LOWER 70S ACROSS
THE PLAINS. EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DISSIPATE
THROUGH 3AM.
THE HIGH PRESSURE OVER THE GREAT BASIN WILL SHIFT EAST ACROSS
COLORADO SUNDAY AND MONDAY. THIS WILL BRING DRIER AIR INTO THE
ROCKIES AND WEAK STEERING FLOWS ALOFT. MODELS GENERATING MORE
ISOLATED SHOWER AND THUNDERSTORM ACTIVITY EACH AFTERNOON AND
EVENING SUNDAY AND MONDAY. GIVEN THE WEAK STEERING FLOWS NOT
ANTICIPATING MUCH STORM MOVEMENT. TEMPERATURES ALOFT WARM AND
HEIGHTS RISE WHICH WILL HELP AFTERNOON HIGHS WARM INTO THE UPPER
70S TO MID 80S ACROSS THE PLAINS.
THE UPPER RIDGE IS FORECAST TO SHIFT EAST INTO THE CENTRAL PLAINS
ON TUESDAY WHILE A STRONG SHORTWAVE TROUGH MOVES OUT OF THE
PACIFIC NORTHWEST INTO THE NORTHERN PLAINS THROUGH THE MIDDLE OF
THE WEEK. THIS WILL SEND A COLD FRONT INTO THE AREA TUESDAY EVENING.
MODELS WANTING TO DEVELOP THUNDERSTORM ACTIVITY ACROSS THE PLAINS
LATE TUESDAY AFTERNOON INTO THE EVENING HOURS...BUT LACK OF
MOISTURE MAY INHIBIT DEVELOPMENT. FOR NOW DO NOT HAVE
THUNDERSTORMS IN THE FORECAST FOR THE PLAINS...BUT THIS WILL NEED
TO BE MONITORED. AFTERNOON HIGHS ON TUESDAY AHEAD OF THE COLD
FRONT WILL REACH INTO THE MID 80S ON THE PLAINS. HIGHS BEHIND THE
COLD FRONT WEDNESDAY THROUGH FRIDAY WILL REMAIN IN THE MID 70S TO
LOWER 80S. SHOWER AND THUNDERSTORM ACTIVITY WILL REMAIN POSSIBLE
OVER THE MOUNTAIN AREAS THROUGH THE END OF THE WEEK. MOZLEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1108 AM MDT FRI MAY 10 2013
MAIN CONCERN TODAY IS CHANCES FOR SHWRS/TS THIS AFTERNOON. A WEAK
DISTURBANCE MOVING FROM N TO S THIS AFTERNOON WILL SPARK SOME SCT
SHOWERS AND ISOLD TS...MAINLY FROM 21Z THROUGH 02Z THIS EVE.
PROB OF PRECIP AT THE TERMINALS IS FAIRLY LOW...20-30 PERCENT...BUT
WILL INCLUDE VCSH IN THE TAFS. THE PROB APPEARS HIGHEST AT KCOS.
PRECIP SHOULD END QUICKLY AFTER SUNSET THIS EVE. OTHERWISE...
EXPECT VFR CONDITIONS AND GENERALLY LIGHT WINDS. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...KT
LONG TERM...MOZLEY
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS MIAMI FL
158 PM EDT FRI MAY 10 2013
.AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE NEXT 24 HOURS.
STILL BELIEVE A FEW SHRAS/TSRAS WILL BE POSSIBLE ACROSS MAINLY THE
INTERIOR AND SHOULD NOT AFFECT ANY TAF SITE. LATEST SHORT TERM
GUIDANCE CONTINUES TO SUGGEST THIS AND ALSO PUSHING SOME OF THE
ACTIVITY EASTWARD...POSSIBLY INTERACTING WITH A WEAK SEA
BREEZE...TOWARD KPBI BY 00Z. KEPT ANY PRECIP MENTION OUT OF KPBI
TAF FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 1007 AM EDT FRI MAY 10 2013/
UPDATE...
LOOKING TO BE A VERY TRICKY FORECAST THIS MORNING. A WEAK MID
LEVEL TROUGH MOVED ACROSS SOUTH FLORIDA DURING THE LATE AFTERNOON
YESTERDAY AND LAST NIGHT SPARKING CONVECTION PARTICULARLY OFFSHORE
THIS MORNING WHICH THEN BUILT BACK ONSHORE. THAT CONVECTION HAS
NOW WANED AS THE TROUGH CONTINUES TO MOVE EAST. THE INTERESTING
PHENOMENA THIS MORNING IS THE 12Z MFL SOUNDING WHICH SHOWS
SIGNIFICANT WARMING AT 500 MB WITH A DISTINCT INVERSION WHICH IS
NEARLY 5K FEET DEEP. THERE HAS ALSO BEEN SOME DRYING ALOFT WITH
PWAT NOW DOWN TO ABOUT 1.25 INCHES WHICH IS SLIGHTLY BELOW THE
AVERAGE FOR EARLY MAY. SO THE QUESTION IS HOW MUCH OF A FACTOR
WILL THESE TWO CONDITIONS HAVE ON CONVECTION DEVELOPING. THE LOW
LEVELS REMAIN SOMEWHAT UNSTABLE BUT THE OVERALL SOUNDING WOULD
MAKE ME BELIEVE THAT CONVECTION WILL STRUGGLE TO BUILD PAST THE
SHOWER STAGE. HOWEVER, MODEL FORECAST SOUNDINGS SHOW MID LEVEL
MOISTURE RETURN ALTHOUGH IT APPEARS THAT THEY MAY BE SUFFERING
FROM CONVECTIVE FEEDBACK. THE MORNING PROFILE ALSO INDICATES VERY
SLOW STORM MOTION TODAY AT UNDER 5 KNOTS WITH A DRIFT BACK TOWARDS
THE EAST COAST LATE IN THE DAY. THE EARLY MORNING HRRR RUNS
INITIALIZED NEARLY PERFECTLY AND SHOW INTERIOR CONVECTION
DEVELOPING OVER THE INTERIOR BETWEEN 17-18Z AND MOVING LITTLE. IT
WILL BE INTERESTING TO SEE WHAT THE LATER RUNS ILLUSTRATE AFTER IT
INGESTS THE 12Z SOUNDINGS. AT ANY RATE, FEEL THE NEED TO SCALE
BACK TO SLIGHT CHANCE THUNDER OVER THE INTERIOR AND CAN MAKE LATER
ASSESSMENTS AS THINGS MATERIALIZE.
KOB
PREV DISCUSSION... /ISSUED 334 AM EDT FRI MAY 10 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUED OVER THE ATLANTIC WATERS JUST
EAST OF THE MIAMI-DADE/BROWARD COUNTY BORDER. A FEW SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED OVER THE METRO AREAS. THESE
SHOWERS AND STORMS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS
A SHORTWAVE EXITS THE REGION.
UPPER RIDGING OVER THE CENTRAL GULF STRETCHING INTO THE LOWER
GREAT LAKES WILL SHIFT EAST TODAY AS A SHORTWAVE TROUGH MOVES FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY. UPPER HEIGHTS WILL
INCREASE OVER SOUTH FLORIDA...WITH MUCH WARMER AND SOMEWHAT DRIER
AIR ALOFT THAN ON THURSDAY. HOWEVER...LOW LEVEL MOISTURE WILL
REMAIN IN PLACE WITH DEWPOINTS IN THE MID 60S TO AROUND 70...SO
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG
THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR THIS AFTERNOON INTO
THE EARLY EVENING. A LIMITING FACTOR EACH DAY THROUGH THE WEEKEND
WILL BE THE SUBTROPICAL RIDGE OVER THE REGION...WITH WARM AND DRY
AIR FROM 850MB TO 600MB. EASTERLY LOW LEVEL FLOW AND LIGHT WINDS
ALOFT WILL ALLOW FOR SLOW STORM MOTION AND FOR STORMS TO STAY
ACROSS THE INTERIOR AND TOWARDS THE GULF COAST. TEMPERATURES WILL
BE WARM...WITH HIGHS IN THE MID 80S TO LOWER 90S. THE EASTERLY LOW
LEVEL FLOW WILL KEEP OVERNIGHT TEMPS WARM IN THE MID 60S TO THE
MID 70S. A FEW SHOWERS MAY DEVELOP OVERNIGHT ACROSS THE ATLANTIC
WATERS...AND MOVE TOWARDS THE EAST COAST.
ANOTHER UPPER LOW WILL MOVE SOUTHEAST ACROSS THE UPPER GREAT LAKES
ON SATURDAY...WITH THE TROUGH DIGGING INTO THE SOUTHEAST. THIS WILL
ALLOW LOW PRESSURE OVER THE NORTHEAST TO DEEPEN...AND A COLD FRONT
EXTENDING FROM THE LOW WILL PUSH INTO THE SOUTHEAST. DEEPER MOISTURE
WILL BEGIN TO POOL SOUTH OF THIS BOUNDARY OVER SOUTHERN GEORGIA AND
NORTHERN FLORIDA. THE UPPER RIDGE WILL FLATTEN AND PUSH SOUTH...AND
THIS SHOULD ALLOW FOR A LITTLE MORE ACTIVITY ALONG THE SEA BREEZE
BOUNDARIES ACROSS THE INTERIOR. SLOW STORM MOTION IS EXPECTED ONCE
AGAIN.
THE FRONTAL BOUNDARY WILL MOVE INTO NORTH AND CENTRAL FLORIDA ON
SUNDAY...AND SURFACE WINDS WILL SHIFT MORE TO THE SOUTH...WITH
SOUTHWEST TO WESTERLY FLOW ABOVE THE SURFACE. THE DRY AIR WILL
REMAIN IN THE LOW/MID LEVELS...SO POP GUIDANCE REMAINS LOW. THE
SURFACE BOUNDARY WILL MOVE INTO SOUTH FLORIDA OVERNIGHT SUNDAY INTO
MONDAY MORNING...WITH THE MOISTURE BOUNDARY LAGGING BEHIND INTO
CENTRAL FLORIDA. THE SURFACE FRONT WILL MOVE THROUGH THE REGION BY
EARLY AFTERNOON...WITH THE MOISTURE SCOURING OUT FROM NORTH TO SOUTH
BEGINNING MID/LATE AFTERNOON. SO RAIN CHANCES SHOULD BE CONFINED TO
THE SOUTHEASTERN HALF OF THE REGION...IF THE MOISTURE HANGS AROUND
AS THE MODELS INDICATE.
HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST ON TUESDAY...WITH DRIER
AIR AND NORTHEASTERLY FLOW. HIGH PRESSURE WILL THEN REMAIN IN
CONTROL OF THE WEATHER THROUGH THE END OF THE FORECAST PERIOD...WITH
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. WITH MODERATE
NORTHEASTERLY FLOW TUESDAY AND WEDNESDAY...THERE WILL A HIGHER
THREAT FOR RIP CURRENTS ALONG THE ATLANTIC BEACHES.
MARINE...
LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
NIGHT INTO TUESDAY. WINDS WILL INCREASE OUT OF THE
NORTHEAST...WITH DETERIORATING MARINE CONDITIONS.
FIRE WEATHER...
MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 86 74 87 / 10 20 20 20
FORT LAUDERDALE 76 86 76 86 / 10 10 10 20
MIAMI 76 88 75 88 / 10 10 10 20
NAPLES 71 86 71 87 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1154 AM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 1146 AM MDT FRI MAY 10 2013
WEAK SHORTWAVE TROUGH ALONG WITH STEEP LAPSE RATES...SOME CAPE AND
NO INHIBITION HAVE ALLOW THUNDERSTORMS TO DEVELOP MORE RAPIDLY AND
FURTHER SOUTH THAN PREVIOUSLY DEPICTED. HRRR WAS NOT DOING TOO BAD
EVEN THOUGH IT DID NOT START FAST...IN CATCHES UP RAPIDLY THOUGH...
USED IT AND REALITY TO INCREASE CHANCE AND COVERAGE OF
THUNDERSTORMS ACROSS THE ENTIRE AREA THROUGH THE REST OF THE
AFTERNOON. TEMPERATURES MAY BE A TAD WARM DUE TO EARLIER ONSET OF
CONVECTION BUT STILL LOOK REASONABLE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 200 AM MDT FRI MAY 10 2013
TODAY-TONIGHT...A WEAK WEATHER DISTURBANCE PRESENTLY ACROSS
SOUTHEAST WYOMING/WESTERN NEBRASKA WILL MOVE THROUGH THE AREA
TODAY PRODUCING A FEW SHOWERS AND POSSIBLE THUNDERSTORMS. THIS
FEATURE IS EXPECTED TO BE OUT OF THE AREA TONIGHT. A COLD FRONT
WILL MOVE SOUTH ACROSS THE AREA SHORTLY AFTER MIDNIGHT. NO
PRECIPITATION IS EXPECTED WITH THE FRONT. HIGHS GENERALLY IN THE
LOW 70S...EXCEPTION BEING FLAGLER AREA WITH MID 60S. LOWS IN THE 40S.
SATURDAY-SATURDAY NIGHT...SURFACE HIGH MOVES IN BEHIND THE FRONT
BRINGING SLIGHTLY COOLER TEMPERATURES. MODELS CONTINUE TO INDICATE
ANOTHER WEATHER DISTURBANCE TO MOVE INTO EASTERN COLORADO DURING
THE AFTERNOON CONTINUING EAST/SOUTHEAST ACROSS MUCH OF THE AREA
SATURDAY NIGHT. WILL MAINTAIN SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGHS 65 TO 70...LOWS IN THE LOW TO MID 40S.
SUNDAY-SUNDAY NIGHT...DRY AND WARMER. HIGHS LOW 70S EAST...MID 70S
TO AROUND 80 WEST. LOWS 45 TO 50.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 200 AM MDT FRI MAY 10 2013
DRY AND MILD EARLY IN THE WEEK...WITH CHANCES FOR STORMS INCREASING
BY MID-WEEK. MUCH UNCERTAINTY IN THE EXACT SYNOPTIC SET-UP...BUT
BELIEVE CONDITIONS WILL BE ADEQUATE TO SUPPORT PRECIP OVER THE
LATER PORTION OF THE WEEK.
MONDAY AND TUESDAY...ALL GUIDANCE CONTINUES TO BE CONSISTENT IN
PROJECTING 850MB TEMPS IN EXCESS OF +25C...WHICH WOULD BE
CONSIDERED WARM FOR JULY LET ALONE MAY. EXPECTING HIGHS TO BE NEAR
90 ON BOTH DAYS...WHICH IS APPROACH RECORD LEVELS. WHILE TUESDAY
HAS SEEMED LIKE THE SLIGHTLY WARMER DAY OF THE TWO FOR THE PAST
FEW SHIFTS...INCREASED CLOUD COVER AS THE GFS IS HINTING TOWARDS
COULD LIMIT TEMPS. CONFIDENCE IS NORMAL TO ABOVE NORMAL.
TUESDAY NIGHT THROUGH THURSDAY...A MORE ACTIVE WEATHER PATTERN
WILL DEVELOP ACROSS THE MIDDLE OF THE WEEK. A WEAK UPPER LOW OVER
THE SOUTHERN CONUS WILL EVOLVE INTO A SLIGHTLY NEGATIVE TROUGH AND
MOVE NORTH ON TUESDAY INTO WEDNESDAY...THEN GRADUALLY MOVE EAST ON
THURSDAY. COULD SEE A FEW SHOWERS/STORMS DEVELOPING ON TUESDAY
NIGHT...BUT THE BETTER CHANCE FOR PRECIP WILL BE ON WED AND THURS
AFTERNOON/EARLY EVENING. TEMPS WED/THU WILL BE DEPENDENT ON CLOUD
COVER...AND WITH MODEL INCONSISTENCY DECIDED TO JUST STICK WITH
THE ALLBLEND /AVERAGE OF ALL MODELS/ GUIDANCE. CONFIDENCE OVER
THIS PERIOD IS NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1146 AM MDT FRI MAY 10 2013
CONVECTION HAS ALREADY DEVELOPED ACROSS THE AREA. EVEN THOUGH HAVE
INSERTED A CHANCE OF TSRA AT BOTH SITES...KGLD WILL HAVE THE BEST
CHANCE AND COULD POSSIBLY BECOME MVFR IF ONE OF THE STRONGER
STORMS MOVES ACROSS...BASED ON LATEST GUIDANCE AND WHAT HAPPENED
YESTERDAY. ACTIVITY SHOULD END QUICKLY AFTER 00Z. COLD FRONT WILL
MOVE THROUGH AFTER 06Z AND CAUSE GUSTY NORTHERLY WINDS THROUGH THE
REST OF THE PERIOD. OUTSIDE OF THUNDERSTORM ACTIVITY...VFR
CONDITIONS ARE EXPECTED THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...JJM
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
340 PM CDT FRI MAY 10 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE FIRST SHOT OF COOLER AIR HAS OVERSPREAD THE AREA WITH THE
ASSOCIATED COLD FRONT NOW ACROSS EXTREME SOUTHEAST MISSOURI AND
SOUTHERN ILLINOIS. EXTENSIVE STRATUS BLANKETS MUCH OF THE AREA AND
EXTENDS WELL NORTH INTO EASTERN IOWA AT MID AFTERNOON. THE MODELS
VARY ON HOW QUICKLY TO CLEAR THE LOW CLOUDS...AND I HAVE SIDED
WITH THE SLOWER RUC AND LOCAL WRF WITH SLOW CLEARING FROM NORTH TO
SOUTH TONIGHT...AND THE SOUTHEAST CWA NOT CLEARING UNTIL AFTER
DAYBREAK ON SATURDAY. A SERIES OF POWERFUL SHORT WAVES NOW ACROSS
MANITOBA AND SASKATCHEWAN WILL DIG SOUTHEASTWARD TONIGHT WITH A
CLOSED LOW EVOLVING. THIS UPPER LOW/TROF WILL CONTINUE TO DEEPEN
WITH A BROAD DEEP LONGWAVE TROF EVOLVING ACROSS THE EASTERN CONUS
BY SATURDAY NIGHT. INTIALLY IN THE PROCESS...THE DIGGING TROF
WILL DRIVE A COLD FRONT ACROSS THE AREA ON SATURDAY. THIS FRONT
WILL USHER A MORE POTENT BLAST OF CHILLY AIR INTO THE REGION ON
THE ORDER OF 2-3 STANDARD DEVIATIONS BELOW NORMAL. IT STILL LOOKS
LIKE THERE WILL BE A CHANCE OF SHOWERS AND EVEN SOME THUNDERSTORMS
FORMING ALONG THE FRONT AS IT MOVES QUICKLY SOUTHEASTWARD. THE
FORCING APPEARS TO BE LARGELY FRONTAL AND THIS SUGGESTS SCATTERED
COVERAGE. INSTABILITY WILL BE WEAK...PROBABLY OVERDONE ON THE NAM
OWING TO TOO HIGH SURFACE DEW POINTS...BUT STILL GREAT ENOUGH TO
SUPPORT A THUNDER THREAT. IT WILL BE A NARROW 1-2 HOUR WINDOW FOR
PRECIPITATION OCCURING WITH THE FRONT AND THEN GUSTY NW WINDS IT
ITS WAKE.
GLASS
.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE DEEP LONGWAVE TROF WILL DOMINATE THE PATTERN AND CONTROL THE
SENSIBLE WEATHER SATURDAY NIGHT INTO EARLY MONDAY WITH A COOL
SURFACE HIGH PREVAILING. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE AND SOME RECORDS COULD BE APPROACHED ON SUNDAY MORNING. THERE
COULD ALSO BE SOME PATCHY FROST WHERE LOWS DIP INTO THE MID 30S.
THE SURFACE HIGH MOVE ACROSS THE AREA ON SUNDAY AND GRADUALLY
RETREAT SOUTHEAST SUNDAY NIGHT INTO THE WESTERN TN VALLEY. THIS
SUGGESTS THAT THE COOLEST TEMPERATURES ON SUNDAY NIGHT AND MONDAY
MORNING WILL BE ACROSS THE EASTERN OZARKS AND SW ILLINOIS WHERE
LOWS IN THE MID-UPPER 30S AND PATCHY FROST WILL ONCE AGAIN BE
POSSIBLE. LOW LEVEL WAA WILL THEN COMMENCE ON MONDAY AND THIS
SHOULD LEAD TO A NICE REBOUND IN TEMPERATURES AS THE LOWER
TROPOSPHERIC FLOW BECOMES MORE SOUTHERLY.
SAY GOODBYE TO THE COOL...I THINK FOR GOOD...BY TUESDAY. THE LONGWAVE
TROF DEPARTS OFF THE EAST COAST AND HEIGHTS RISE ALOFT AS A SHORT
WAVE RIDGE BUILDS INTO THE MS VALLEY. STRONG WAA WILL PROGRESS AND
H85 TEMPS ARE FORECAST TO RISE ABOVE +18 DEGC ON ALL THE GUIDANCE...
SUPPORTING HIGHS WELL INTO THE 80S. MOISTURE AND CLOUDS WILL BEGIN
TO INCREASE LATE WEDNESDAY AS A NEW UPSTREAM TROF MOVES ACROSS THE
PLAINS AND EVENTUALLY INTO THE MS VALLEY BY THURSDAY. THE MODELS
DISAGREE ON WHETHER AN EAST-WEST FRONT WILL ALSO DROP INTO THE
AREA DURING THIS TIME...BUT THE PRESENCE OF THE UPPER TROF ALONE
SUPPORTS A CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE LATER
PART OF THE WEEK.
GLASS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1200 PM CDT FRI MAY 10 2013
LARGE AREA OF POST FRONTAL MVFR CIGS WILL LAST WELL INTO THE
EVENING OVER TAF SITES...THEN SLOWLY LIFT AND SCATTER OUT DURING
THE OVERNIGHT PERIOD. NW WINDS WILL DIMINISH BY AROUND
MIDNIGHT...THEN BECOME LIGHT AND VARIABLE BY DAYBREAK ON SATURDAY.
A SECONDARY COLD FRONT WILL MOVE THROUGH THE AREA FROM MID MORNING
NEAR KUIN...TO AROUND NOON AT KSTL. AN AREA OF CIGS NEAR 030 WILL
ACCOMPANY THIS FRONT...WITH A SMALL CHANCE FOR SHOWERS AS
REFLECTED IN THE VCSH. NW WINDS WILL AGAIN INCREASE BEHIND THIS
FRONT AND BECOME GUSTY.
SPECIFICS FOR KSTL...
MVFR CIGS WILL SLOWLY LIFT THEN SCATTER OUT BY 0900Z. NW WINDS
WILL DIMINISH SHORTLY AFTER SUNSET...THEN BECOME LIGHT AND
VARIABLE BY DAWN ON SATURDAY. SECONDARY COLD FRONT WILL MOVE
THROUGH TAF SITE AROUND NOON...BRINGING WIDELY SCATTERED SHOWERS
AND INCREASING NW WINDS.
WEBBER/BROWNING
&&
.CLIMATE...
ISSUED AT 328 PM CDT FRI MAY 10 2013
RECORD LOWS
5/125/13
ST LOUIS39 (1960)40 (1971)
COLUMBIA35 (1892)34 (1901)
QUINCY35 (1960)35 (1971)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BISMARCK ND
107 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 105 PM CDT FRI MAY 10 2013
NO MAJOR CHANGES WERE MADE TO THE FORECAST FOR THIS UPDATE. A COLD
FRONT LOCATED JUST NORTH OF BISMARCK CONTINUES TO PUSH SOUTH AND
SHOULD BE OUT OF NORTH DAKOTA LATER THIS AFTERNOON. BEHIND THE
FRONT WINDS CONTINUE TO STRONG WITH GUSTS UP TO 40 MPH. ALL
FORECAST GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT TRENDS AND
OBSERVATIONS.
UPDATE ISSUED AT 1035 AM CDT FRI MAY 10 2013
THE MAIN IMPACTS FOR THE SHORT TERM UPDATE ARE GUSTY WINDS AND FIRE
DANGER.
A STRONG COLD FRONT CURRENTLY LOCATED NEAR MINOT WILL QUICKLY
BLAST SOUTH OUT OF NORTH DAKOTA BY LATE AFTERNOON. BEHIND THE
FRONT PRESSURE RISES NEAR 5 MB WITHIN THE LAST THREE HOURS WILL
DRIVE SUSTAINED WINDS NEAR 30 MPH AND FREQUENT GUSTS UP TO 45 MPH.
THEREFORE A WIND ADVISORY WAS ISSUED. THESE GUSTY WINDS AND VERY
DRY AIR WILL CONTINUE TO DRIVE DOWN RELATIVE HUMIDITIES AND FIRE
DANGER UP.
PRECIPITATION CHANCES WERE LOWERED FOR THIS UPDATE. LATEST GUIDANCE
FROM THE 13 UTC RAP AND 14 UTC HRRR SHOW VERY LITTLE PRECIPITATION
DEVELOPING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE
AFTERNOON HOURS. LATEST OBSERVATIONS SHOW VERY DRY AIR AT THE
SURFACE AND ONLY LIGHT RAIN SHOWER ECHOS SHOWING UP ON RADAR. BEST
CHANCE OF PRECIPITATION STILL LOOKS TO BE ACROSS FAR SOUTHERN
NORTH DAKOTA LATE THIS AFTERNOON AS PEAK HEATING WILL INCREASE
INSTABILITY AND PROXIMITY TO A MORE MOIST AIRMASS MAY PROVIDE ENOUGH
TO SPAWN SOME SCATTERED SHOWERS AND THUNDERSTORMS.
UPDATE ISSUED AT 652 AM CDT FRI MAY 10 2013
COLD FRONT EXTENDING SOUTHWEST FROM A SURFACE LOW NEAR LAKE
WINNIPEG WILL MOVE INTO NORTHWEST NORTH DAKOTA SHORTLY. INCREASING
CLOUDS AND A FEW SHOWERS SHOWING UP OVER SOUTHERN SASKATCHEWAN AND
MANITOBA. CURRENT FORECAST HAS A GOOD HANDLE ON CURRENT PLACEMENT
OF CLOUDS AND PRECIPITATION. ONLY CHANGES TO THE FORECAST WERE TO
UPDATE CURRENT SENSIBLE WEATHER ELEMENTS. THIS DROPPED OUR
OVERNIGHT LOWS SOME ACROSS CENTRAL NORTH DAKOTA WHERE CLEAR SKIES
AND LIGHT WINDS ALLOWED TEMPERATURES TO DROP A BIT BELOW FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT FRI MAY 10 2013
MAIN HIGHLIGHT FOR THE SHORT TERM WILL BE THE APPROACHING COLD FRONT
AND RESULTING WEATHER IMPACTS INCLUDING FIRE WEATHER CONCERNS.
CURRENTLY...WATER VAPOR SATELLITE IMAGERY INDICATES UPPER LEVEL
SHORTWAVE OVER SOUTHERN MANITOBA/SASKATCHEWAN MOVING SOUTHEASTWARD.
THIS FEATURE HANDLED WELL BY THE MODELS AND WILL USE A MODEL BLEND
FOR FORECAST DETAILS. SURFACE COLD FRONT ASSOCIATED WITH THE UPPER
LEVEL SHORTWAVE EXTENDED FROM NORTHERN LAKE WINNIPEG ACROSS SOUTHERN
SASKATCHEWAN TO NORTH CENTRAL MONTANA. AHEAD OF THE FRONT WINDS WERE
LIGHT AND FROM THE SOUTH.
THE COLD FRONT IS PROGGED TO REACH THE NORTHWEST CORNER OF THE STATE
AROUND SUNRISE AND CONTINUE MOVING SOUTHEASTWARD. BY AROUND NOON CDT
THE FRONT SHOULD BE APPROACHING DICKINSON/GARRISON/DEVILS LAKE AREA
AND REACH THE JAMESTOWN AREA BY MID-LATE AFTERNOON. AHEAD OF THE
FRONT THE SOUTH WINDS SHOULD BECOME MORE SOUTHWESTERLY AND BEGIN
INCREASING...THEN AFTER THE FRONT PASSES WINDS SHOULD BECOME
NORTHWEST AND INCREASE TO 20 TO 30 MPH. BUFKIT SOUNDINGS AND LOOKING
AT H850 FORECAST WINDS...THERE SHOULD BE GOOD LINKAGE ALOFT TO ABOVE
H800 AND WINDS AROUND H850 ARE AROUND 30 KNOTS. THUS SUSTAINED WINDS
SHOULD BE JUST SHY OF WIND ADVISORY CRITERIA OF 30 MPH FOR 3 HOURS
OR MORE. WIND GUSTS COULD BE AS HIGH AS 35 TO POSSIBLY 40 MPH IN
SOME LOCALES.
THESE STRONG WINDS COMBINED WITH DRY GRASSLANDS WILL RAISE FIRE
WEATHER CONCERNS. SEE THE FIRE WEATHER SECTION BELOW FOR DETAILS.
THE COLD FRONT IS PROGGED TO EXTEND ACROSS SOUTHERN NORTH DAKOTA
THIS AFTERNOON - DURING PEAK HEATING OF THE DAY. CAPE VALUES ARE
200-400 FOR THE MID AND LATE AFTERNOON/EARLY EVENING HOURS AND WILL
KEEP THE CHANCE OF RAIN SHOWERS NORTHWEST AND NORTH CENTRAL NORTH
DAKOTA THIS MORNING AND THUNDERSHOWERS SOUTHWEST AND SOUTH CENTRAL
THIS AFTERNOON. LOOKING AT HIGH TEMPERATURES FROM THE 60S NORTH TO
THE LOW TO MID 70S SOUTH.
WINDS SHOULD DECREASE DURING THE EVENING WITH COOL AND DRY AIR
PUSHING INTO THE STATE. LOWS TONIGHT SHOULD DIP INTO THE 20S TO
LOWER 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 410 AM CDT FRI MAY 10 2013
WE BEGIN THE EXTENDED PERIOD ON THE COOL SIDE WITH CANADIAN HIGH
PRESSURE OVER THE REGION SATURDAY MORNING. STRONG UPPER LEVEL
RIDGING OVER THE WESTERN U.S. SATURDAY WILL TRANSLATE EAST THROUGH
THE WEEKEND BRINGING WARMER TEMPERATURES TO WESTERN NORTH DAKOTA ON
SUNDAY. DRY CONDITIONS ARE EXPECTED SATURDAY THROUGH SUNDAY.
A WEAK SURFACE TROUGH MOVES INTO THE AREA SUNDAY NIGHT...ASSOCIATED
WITH A NORTHERN STREAM WAVE THAT FLATTENS THE UPPER RIDGE THAT HAS
MOVED OVER THE NORTHERN PLAINS. MODELS ARE DEPICTING VERY LIGHT QPF
ALONG THE TROUGH BUT WITH ABUNDANT DRY AIR OVER THE REGION...WILL
HOLD OFF ON INTRODUCING A MENTION OF SHOWERS AT THIS TIME.
UPPER RIDGE BUILDS BACK ON MONDAY BEHIND THE SURFACE TROUGH AND IN
RESPONSE TO A WAVE MOVING ONTO THE NORTHWESTERN U.S. COAST. THIS
SHOULD SET THE STAGE FOR AN UNSEASONABLY WARM MONDAY WITH NEAR
RECORD HIGH TEMPERATURES OVER THE SOUTHWEST AND SOUTH CENTRAL.
RECORD HIGH FOR BISMARCK MONDAY IS 91 DEGREES...WITH A FORECAST HIGH
OF 89. OTHER FIRST ORDER STATION HIGHS ARE IN THE MID 90S AND WOULD
BE HARDER TO REACH.
THE UPPER RIDGE BREAKS DOWN MONDAY NIGHT AS THE NORTHWEST U.S.
TROUGH MOVES INTO THE NORTHERN ROCKIES AND A QUASI-ZONAL FLOW TAKES
SHAPE MONDAY NIGHT THROUGH THURSDAY. TEMPERATURES AFTER MONDAY WILL
RETURN TO NORMAL...AROUND 70 DEGREES FOR HIGHS. WITH A PROGRESSIVE
WESTERLY FLOW...PRECIPITATION CHANCES CANNOT BE RULED OUT OF
PRETTY MUCH ANY PERIOD FROM MONDAY NIGHT THROUGH THURSDAY. ALTHOUGH
ANY SHOWERS OR THUNDERSTORMS WOULD LIKELY BE SPOTTY. UTILIZED A
MODEL BLEND WITH PERSISTENCE FOR POPS WHICH PRETTY MUCH GIVES SLIGHT
CHANCE POPS THROUGH THE PERIOD. UNFORTUNATELY WITH MODEL TIMING AND
PLACEMENT DIFFERENCES IN THIS PROGRESSIVE FLOW ITS TOO HARD AT
THIS TIME TO TRY AND NAIL DOWN A SPECIFIC PERIOD FOR
PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 105 PM CDT FRI MAY 10 2013
A STRONG COLD FRONT JUST NORTH OF KBIS WILL CONTINUE SOUTH AND
EXIT NORTH DAKOTA BY LATE AFTERNOON. STRONG NORTHWEST WINDS WITH
GUSTS OF 25-35 KTS ARE EXPECTED BEHIND THE FRONT. ISOLATED TO
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY IS ALSO POSSIBLE NEAR
THE FRONT AT KDIK...KBIS AND KJMS.
&&
.FIRE WEATHER...
ISSUED AT 410 AM CDT FRI MAY 10 2013
THE FIRE WEATHER WATCH THAT WAS IN EFFECT FOR PORTIONS OF
NORTHWEST...NORTH CENTRAL...AND SOUTHWESTERN NORTH DAKOTA WILL BE
UPGRADED TO A RED FLAG WARNING. EXPECT DEWPOINTS TO RISE WITH THE
APPROACH OF THE COLD FRONT...THEN DROP INTO THE 20S BEHIND IT. WENT
WITH THESE LOWER DEWPOINTS THAN MODELS/GUIDANCE WOULD SUGGEST.
EXPECT THE SURFACE/BOUNDARY LAYER WILL MIX WELL UP TO H800 AND
LOWER DEWPOINTS THIS AFTERNOON. MINIMUM RELATIVE HUMIDITY VALUES
ARE EXPECTED TO BE AROUND 20 TO 25 PERCENT FOR MUCH OF WESTERN AND
PARTS OF CENTRAL NORTH DAKOTA. EXPECT AFTERNOON NORTHWEST WINDS OF
25 TO 30 MPH COMBINED WITH THE LOW RELATIVE HUMIDITY AND VERY DRY
PASTURES WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS. THESE
CONDITIONS WOULD SUPPORT RAPID FIRE SPREAD SHOULD A FIRE IGNITE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>003-009>011-017>019-021-031>033.
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>005-009>013-017>023-031>035-040>046.
&&
$$
UPDATE...AJ
SHORT TERM...JV
LONG TERM...TWH
AVIATION...AJ
FIRE WEATHER...JV
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
531 PM EDT FRI MAY 10 2013
.SYNOPSIS...
SOUTHWEST FLOW AND MOISTURE WILL INCREASE TODAY THROUGH TONIGHT
AHEAD OF AN APPROACHING COLD FRONT. MOISTURE AND INSTABILITY WILL
LINGER THROUGH SATURDAY AS A SECOND REINFORCING FRONT APPROACHES
FROM THE NORTHWEST. THIS FRONT WILL CROSS THE REGION SUNDAY MORNING
AND USHER IN A DRIER AIRMASS ALONG WITH MUCH COOLER TEMPERATURES.
COOL HIGH PRESSURE WILL LINGER MONDAY THROUGH TUESDAY...WITH
TEMPERATURES REBOUNDING MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
2130 UTC UPDATE...POPS HAVE BEEN ADJUSTED PER SATELLITE
IMAGERY...WITH INCREASES NEAR KGSP AND KGMU...AND LOWER VALUES
ELSEWHERE.
AS OF 200 PM...A PRE-FRONTAL SHORTWAVE TROF...ASSOCIATED WITH A PAIR
OF MCV/S WILL CROSS THE CWFA THIS EVENING. THE ENVIRONMENT IS FAIRLY
UNSTABLE...WITH SBCAPES IN THE 1000-1500 J/KG...HIGHEST ACRS THE
UPSTATE AND NE GA. DIFFERENTIAL HEATING IN THE MTNS AND ALONG EDGE
OF THE THICKER CIRRUS SHIELD IS HELPING TO INITIATE SCATTERED SHWR
COVERAGE ALREADY EARLY THIS AFTN. THE 16Z HRRR SEEMS TO HAVE THE
CLOSEST IDEA OF THE ACTIVITY COVERAGE...AND IT TAKES IT EWD ACRS THE
CWFA THRU THE REST OF THE AFTN...BRINGING IN THE MORE STABLE MCV AIR
IN FROM THE WEST. THE ENVIRONMENT STILL DOES NOT LOOK ALL THAT
IMPRESSIVE FROM A SEVERE THREAT STANDPOINT. SO WILL CONTINUE TO ONLY
MENTION LGTNG/HVY RAIN IN HWO. AS FOR HYDRO/HVY RAIN THREAT...WITH
THE MOVEMENT OF THE SHORTWAVE AND OVERALL CONVECTION...THINK ANY
AREAS RECEIVING AN INCH OR MORE WITH ONE STORM IS STILL FAIRLY LOW.
MOST AREAS PROBABLY WILL RECEIVE LESS THAN A QUARTER INCH THRU
TONIGHT.
AS COLD FRONT APPROACHES FROM THE WEST...PROFILES ACRS THE CWFA
REMAIN MOIST...WITH PERSISTENT DEEP LAYER WEAK-MOD Q-VECTOR
CONVERGENCE. CONVECTION ALLOWING MODELS DO SHOW MAINLY DEBRIS SHWRS
WITH POTENTIALLY A FEW RUMBLES OF THUNDER OVERNIGHT. THE MAIN
LIMITING FACTOR TO MORE ROBUST CONVECTION/HEAVY RAIN WILL BE ONGOING
CONVECTION ALONG THE GULF COAST...WHICH WILL ROB THE SRN
APPALACHIANS OF THE HIGHER PWAT AIR. WILL CONTINUE WITH 30-40 POP IN
THE PIEDMONT AND 50-60 IN THE MTNS. TEMPS WILL BE ABOVE NORMAL IN
THE MOIST PRE-FRONTAL AIR MASS.
SATURDAY...COLD FRONT AND ASSOCIATED MID LVL SHORTWAVE TROF WILL
CROSS THE AREA DURING THE DAY. LLVL FLOW VEERS TO NEARLY DUE
WESTERLY AHEAD OF THE SFC BNDRY...WITH PWATS DROPPING. WILL CONTINUE
WITH LIKELY POPS IN THE NC ZONES...AND HIGH-END CHC SOUTH. SEVERE
THREAT LOOKS TO STAY EAST WHERE BETTER SHEAR AND INSTBY WILL SET UP.
QPF STILL LOOKS TO BE LIMITED...AS STORMS SHUD HAVE DECENT EWD
MOTION...AND DRY AIR BEGINS TO FILTER IN. TEMPS ARE EXPECTED TO
REACH THE 70S BELOW 3500 FT...TO LWR 80S IN THE LWR PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT FRIDAY...A STRONG UPPER LOW WILL MOVE ACROSS THE
GREAT LAKES STATES SATURDAY NIGHT AND SUNDAY. THIS WILL PUSH A COLD
FRONT ACROSS THE REGION EARLY ON SUNDAY. SATURDAY NIGHT THE UPPER
LEVEL FLOW WILL BACK JUST A BIT AHEAD OF THE ADVANCING UPPER
LOW...THOUGH THE LLVL FLOW WILL REMAIN OUT OF THE WEST TO NORTHWEST.
INSTABILITY WILL BE QUITE LIMITED AFTER MID-EVENING...AND WHILE
THERE WILL BE SOME FORCING FOR SHOWERS AND TSTMS OVER THE EASTERN
ZONES...THE THREAT OF SEVERE WEATHER WILL BE MINIMAL.
BY SUNDAY MORNING A BAND OF LOW TOPPED SHOWERS MAY MOVE INTO THE
MOUNTAINS ALONG THE TRUE COLD FRONT. ANY MEASURE RAINFALL WITH THESE
SHOWERS SHOULD BE CONFINED TO THE IMMEDIATE TENNESSEE BORDER.
SUNDAY WILL BE PLEASANTLY MILD. IT WILL BE BREEZY ACROSS THE
MOUNTAINS AS SKIES CLEAR. AS COOL HIGH PRESSURE BUILDS IN FOR SUNDAY
NIGHT...SOME INTERIOR VALLEYS MAY SEE AREAS OF FROST. AND CERTAIN
HIGH ELEVATIONS COULD EXPERIENCE AN ADVECTIVE FROST. WITH HIGH
PRESSURE STILL BUILDING INTO THE REGION...THERE SHOULD STILL BE
ENOUGH OF FLOW THROUGH THE MAJOR VALLEYS TO KEEP FROST FROM FORMING.
OVERALL...CONFIDENCE IS GOOD THAT SHELTERED VALLEYS WILL SEE SOME
FROST...THOUGH I/M NOT CERTAIN HOW WIDESPREAD IT WILL BE AT THIS
POINT. WE WILL CONTINUE TO MENTION THIS POSSIBILITY IN THE HWO.
MONDAY WILL BE SUNNY AND PLEASANT WITH MAX TEMPS RUNNING ABOUT 10
DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...THE GLOBAL MODELS CONTINUE TO AGREE THAT
THE SHARP UPPER TROUGH AXIS WILL MOVE OFFSHORE MON NIGHT FOLLOWED BY
UPPER RIDGING TUE/WED. THE UPPER RIDGE AXIS WILL CROSS THE FORECAST
AREA WED NIGHT AND THE UPPER PATTERN BECOMES SWLY BY THU WITH A LOW
AMPLITUDE UPPER TROUGH APPROACHING FROM THE WEST. THE TROUGH AXIS
WILL THEN CROSS THE REGION ON FRI.
AT THE SURFACE...COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN
MON NIGHT AND SETTLES OVER THE REGION TUE. TEMPS ON MON NIGHT SHOULD
RUN 10-15 DEGREES BELOW NORMAL WITH FROST/FREEZE POSSIBLE OVER THE
NC MOUNTAINS/VALLEYS. MAX TEMPS ON TUE WILL REBOUND 2 TO 3 DEGREES
BUT STILL LIKELY REMAIN 5-10 DEGREES BELOW NORMAL. TEMPS QUICKLY
WARM UP TO NEAR NORMAL BY WED AFTERNOON AS THE CENTER OF HIGH
PRESSURE MOVES OFFSHORE AND RETURN SWLY FLOW DEVELOPS OVER THE
REGION. THE HIGH WILL REMAIN CENTERED OFF THE ATLANTIC COAST THU
WITH ITS SURFACE RIDGE EXTENDING INTO THE CWA. CONDITIONS LOOK DRY
THROUGH WED AND I/VE MENTIONED 20/30 PERCENT POPS FOR THUNDERSTORMS
LATE THURSDAY...MAINLY IN THE MOUNTAINS DUE TO INCREASING
MOISTURE/BUOYANCY. A SURFACE COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIANS BY THU NIGHT AND TRAVERS THE FORECAST AREA ON FRI.
HOWEVER...MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT MOVES
ACROSS REGION. THEREFORE...I HAVE KEPT POPS IN THE 20 TO 30 PERCENT
RANGE ON FRI. TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL THU/FRI.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A THIN BKN-OVC CIRRUS LAYER HAS STREAMED INTO THE AREA
FROM THE WEST...BUT IS NOT ENUF TO INHIBIT CONVECTIVE CUMULUS TO
DEVELOP TO THE WEST OF THE TERMINAL. SCATTERED SHRA AND A FEW TSRA
ARE EXPECTED TO DEVELOP ACRS THE AREA DURING THE AFTN HOURS. FOR
NOW...WILL GO WITH A TEMPO SHRA DURING THE PEAK HEATING HOURS...AS
TS CHCS TOO LOW ATTM. MAY NEED TO ADD IN TS MENTION...POSSIBLY AS A
TEMPO GROUP WITH A LATER AMD...IF COVERAGE ENDS UP GREATER THAN
EXPECTED. OTHERWISE...SW WINDS ARE GENERALLY 10-15 KTS WITH GUSTS
NEAR 20 KTS. THEY SHUD DIMINISH AROUND SUNSET SLIGHTLY AND LOSE THE
GUSTINESS. THERE WILL BE PLENTY OF MID AND UPR LVL MOISTURE
LINGERING OVERNIGHT...WITH SOME SHRA/TSRA POSSIBLE...ESP IN THE
09Z-12Z TIME FRAME. NOT CONFIDENT ENUF ON TS TO HAVE PROB30
THERE...BUT STILL EXPECT ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY
MORNING...WHICH WARRANTS A PROB30 AFTER 13Z. GUIDANCE NOT INDICATING
ANY RESTRICTIONS...BUT SOME FOG/STRATUS IS POSSIBLE LATE TNGT IF
THERE IS MORE RAINFALL THAN EXPECTED THIS AFTN/EVE.
ELSEWHERE...SCATTERED SHRA HAVE ALREADY DEVELOPED BEFORE THE 18Z TAF
ISSUANCE TO THE WEST OF A KAVL/KGMU/KAND LINE. THIS ACTIVITY IS
EXPECTED TO INCREASE IN COVERAGE AND SPREAD ACRS THE TAF SITES THIS
AFTN THRU ABOUT SUNSET. THE SCATTERED NATURE OF THE ACTIVITY SEEMS
TO WARRANT JUST VCTS MENTIONS FOR NOW. THERE WILL BE PLENTY OF MID
AND UPR LVL MOISTURE LINGERING OVERNIGHT...WITH SOME SHRA/TSRA
POSSIBLE. OVERALL...NOT EXPECTING MUCH FOG/STRATUS
POTENTIAL...EXCEPT IF A SITE IS HIT DIRECTLY BY A SHRA. STILL EXPECT
ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY MORNING...WHICH WARRANTS A
PROB30 AFTER DAYBREAK AT ALL SITES.
OUTLOOK...THE FIRST OF TWO COLD FRONT WILL SWEEP ACROSS THE REGION
ON SATURDAY. THE SECOND COLD FRONT WILL PASS EARLY SUNDAY. SHOWERS
AND THUNDERSTORMS WILL DEVELOP AHEAD OF THESE FRONTS...ESPECIALLY
SATURDAY. DRY WEATHER WILL BEGIN ON MONDAY.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...ARK/JAT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
344 PM EDT FRI MAY 10 2013
.SYNOPSIS...
SOUTHWEST FLOW AND MOISTURE WILL INCREASE TODAY THROUGH TONIGHT
AHEAD OF AN APPROACHING COLD FRONT. MOISTURE AND INSTABILITY WILL
LINGER THROUGH SATURDAY AS A SECOND REINFORCING FRONT APPROACHES
FROM THE NORTHWEST. THIS FRONT WILL CROSS THE REGION SUNDAY MORNING
AND USHER IN A DRIER AIRMASS ALONG WITH MUCH COOLER TEMPERATURES.
COOL HIGH PRESSURE WILL LINGER MONDAY THROUGH TUESDAY...WITH
TEMPERATURES REBOUNDING MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
1945 UTC UPDATE...POPS HAVE BEEN RAISED IN THE NORTHERN AND SOUTHERN
NC MOUNTAINS PER RADAR TRENDS. SKY COVER WAS UPDATED FROM VISIBLE
SATELLITE IMAGERY.
AS OF 200 PM...A PRE-FRONTAL SHORTWAVE TROF...ASSOCIATED WITH A PAIR
OF MCV/S WILL CROSS THE CWFA THIS EVENING. THE ENVIRONMENT IS FAIRLY
UNSTABLE...WITH SBCAPES IN THE 1000-1500 J/KG...HIGHEST ACRS THE
UPSTATE AND NE GA. DIFFERENTIAL HEATING IN THE MTNS AND ALONG EDGE
OF THE THICKER CIRRUS SHIELD IS HELPING TO INITIATE SCATTERED SHWR
COVERAGE ALREADY EARLY THIS AFTN. THE 16Z HRRR SEEMS TO HAVE THE
CLOSEST IDEA OF THE ACTIVITY COVERAGE...AND IT TAKES IT EWD ACRS THE
CWFA THRU THE REST OF THE AFTN...BRINGING IN THE MORE STABLE MCV AIR
IN FROM THE WEST. THE ENVIRONMENT STILL DOES NOT LOOK ALL THAT
IMPRESSIVE FROM A SEVERE THREAT STANDPOINT. SO WILL CONTINUE TO ONLY
MENTION LGTNG/HVY RAIN IN HWO. AS FOR HYDRO/HVY RAIN THREAT...WITH
THE MOVEMENT OF THE SHORTWAVE AND OVERALL CONVECTION...THINK ANY
AREAS RECEIVING AN INCH OR MORE WITH ONE STORM IS STILL FAIRLY LOW.
MOST AREAS PROBABLY WILL RECEIVE LESS THAN A QUARTER INCH THRU
TONIGHT.
AS COLD FRONT APPROACHES FROM THE WEST...PROFILES ACRS THE CWFA
REMAIN MOIST...WITH PERSISTENT DEEP LAYER WEAK-MOD Q-VECTOR
CONVERGENCE. CONVECTION ALLOWING MODELS DO SHOW MAINLY DEBRIS SHWRS
WITH POTENTIALLY A FEW RUMBLES OF THUNDER OVERNIGHT. THE MAIN
LIMITING FACTOR TO MORE ROBUST CONVECTION/HEAVY RAIN WILL BE ONGOING
CONVECTION ALONG THE GULF COAST...WHICH WILL ROB THE SRN
APPALACHIANS OF THE HIGHER PWAT AIR. WILL CONTINUE WITH 30-40 POP IN
THE PIEDMONT AND 50-60 IN THE MTNS. TEMPS WILL BE ABOVE NORMAL IN
THE MOIST PRE-FRONTAL AIR MASS.
SATURDAY...COLD FRONT AND ASSOCIATED MID LVL SHORTWAVE TROF WILL
CROSS THE AREA DURING THE DAY. LLVL FLOW VEERS TO NEARLY DUE
WESTERLY AHEAD OF THE SFC BNDRY...WITH PWATS DROPPING. WILL CONTINUE
WITH LIKELY POPS IN THE NC ZONES...AND HIGH-END CHC SOUTH. SEVERE
THREAT LOOKS TO STAY EAST WHERE BETTER SHEAR AND INSTBY WILL SET UP.
QPF STILL LOOKS TO BE LIMITED...AS STORMS SHUD HAVE DECENT EWD
MOTION...AND DRY AIR BEGINS TO FILTER IN. TEMPS ARE EXPECTED TO
REACH THE 70S BELOW 3500 FT...TO LWR 80S IN THE LWR PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT FRIDAY...A STRONG UPPER LOW WILL MOVE ACROSS THE
GREAT LAKES STATES SATURDAY NIGHT AND SUNDAY. THIS WILL PUSH A COLD
FRONT ACROSS THE REGION EARLY ON SUNDAY. SATURDAY NIGHT THE UPPER
LEVEL FLOW WILL BACK JUST A BIT AHEAD OF THE ADVANCING UPPER
LOW...THOUGH THE LLVL FLOW WILL REMAIN OUT OF THE WEST TO NORTHWEST.
INSTABILITY WILL BE QUITE LIMITED AFTER MID-EVENING...AND WHILE
THERE WILL BE SOME FORCING FOR SHOWERS AND TSTMS OVER THE EASTERN
ZONES...THE THREAT OF SEVERE WEATHER WILL BE MINIMAL.
BY SUNDAY MORNING A BAND OF LOW TOPPED SHOWERS MAY MOVE INTO THE
MOUNTAINS ALONG THE TRUE COLD FRONT. ANY MEASURE RAINFALL WITH THESE
SHOWERS SHOULD BE CONFINED TO THE IMMEDIATE TENNESSEE BORDER.
SUNDAY WILL BE PLEASANTLY MILD. IT WILL BE BREEZY ACROSS THE
MOUNTAINS AS SKIES CLEAR. AS COOL HIGH PRESSURE BUILDS IN FOR SUNDAY
NIGHT...SOME INTERIOR VALLEYS MAY SEE AREAS OF FROST. AND CERTAIN
HIGH ELEVATIONS COULD EXPERIENCE AN ADVECTIVE FROST. WITH HIGH
PRESSURE STILL BUILDING INTO THE REGION...THERE SHOULD STILL BE
ENOUGH OF FLOW THROUGH THE MAJOR VALLEYS TO KEEP FROST FROM FORMING.
OVERALL...CONFIDENCE IS GOOD THAT SHELTERED VALLEYS WILL SEE SOME
FROST...THOUGH I/M NOT CERTAIN HOW WIDESPREAD IT WILL BE AT THIS
POINT. WE WILL CONTINUE TO MENTION THIS POSSIBILITY IN THE HWO.
MONDAY WILL BE SUNNY AND PLEASANT WITH MAX TEMPS RUNNING ABOUT 10
DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...THE GLOBAL MODELS CONTINUE TO AGREE THAT
THE SHARP UPPER TROUGH AXIS WILL MOVE OFFSHORE MON NIGHT FOLLOWED BY
UPPER RIDGING TUE/WED. THE UPPER RIDGE AXIS WILL CROSS THE FORECAST
AREA WED NIGHT AND THE UPPER PATTERN BECOMES SWLY BY THU WITH A LOW
AMPLITUDE UPPER TROUGH APPROACHING FROM THE WEST. THE TROUGH AXIS
WILL THEN CROSS THE REGION ON FRI.
AT THE SURFACE...COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN
MON NIGHT AND SETTLES OVER THE REGION TUE. TEMPS ON MON NIGHT SHOULD
RUN 10-15 DEGREES BELOW NORMAL WITH FROST/FREEZE POSSIBLE OVER THE
NC MOUNTAINS/VALLEYS. MAX TEMPS ON TUE WILL REBOUND 2 TO 3 DEGREES
BUT STILL LIKELY REMAIN 5-10 DEGREES BELOW NORMAL. TEMPS QUICKLY
WARM UP TO NEAR NORMAL BY WED AFTERNOON AS THE CENTER OF HIGH
PRESSURE MOVES OFFSHORE AND RETURN SWLY FLOW DEVELOPS OVER THE
REGION. THE HIGH WILL REMAIN CENTERED OFF THE ATLANTIC COAST THU
WITH ITS SURFACE RIDGE EXTENDING INTO THE CWA. CONDITIONS LOOK DRY
THROUGH WED AND I/VE MENTIONED 20/30 PERCENT POPS FOR THUNDERSTORMS
LATE THURSDAY...MAINLY IN THE MOUNTAINS DUE TO INCREASING
MOISTURE/BUOYANCY. A SURFACE COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIANS BY THU NIGHT AND TRAVERS THE FORECAST AREA ON FRI.
HOWEVER...MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT MOVES
ACROSS REGION. THEREFORE...I HAVE KEPT POPS IN THE 20 TO 30 PERCENT
RANGE ON FRI. TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL THU/FRI.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A THIN BKN-OVC CIRRUS LAYER HAS STREAMED INTO THE AREA
FROM THE WEST...BUT IS NOT ENUF TO INHIBIT CONVECTIVE CUMULUS TO
DEVELOP TO THE WEST OF THE TERMINAL. SCATTERED SHRA AND A FEW TSRA
ARE EXPECTED TO DEVELOP ACRS THE AREA DURING THE AFTN HOURS. FOR
NOW...WILL GO WITH A TEMPO SHRA DURING THE PEAK HEATING HOURS...AS
TS CHCS TOO LOW ATTM. MAY NEED TO ADD IN TS MENTION...POSSIBLY AS A
TEMPO GROUP WITH A LATER AMD...IF COVERAGE ENDS UP GREATER THAN
EXPECTED. OTHERWISE...SW WINDS ARE GENERALLY 10-15 KTS WITH GUSTS
NEAR 20 KTS. THEY SHUD DIMINISH AROUND SUNSET SLIGHTLY AND LOSE THE
GUSTINESS. THERE WILL BE PLENTY OF MID AND UPR LVL MOISTURE
LINGERING OVERNIGHT...WITH SOME SHRA/TSRA POSSIBLE...ESP IN THE
09Z-12Z TIME FRAME. NOT CONFIDENT ENUF ON TS TO HAVE PROB30
THERE...BUT STILL EXPECT ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY
MORNING...WHICH WARRANTS A PROB30 AFTER 13Z. GUIDANCE NOT INDICATING
ANY RESTRICTIONS...BUT SOME FOG/STRATUS IS POSSIBLE LATE TNGT IF
THERE IS MORE RAINFALL THAN EXPECTED THIS AFTN/EVE.
ELSEWHERE...SCATTERED SHRA HAVE ALREADY DEVELOPED BEFORE THE 18Z TAF
ISSUANCE TO THE WEST OF A KAVL/KGMU/KAND LINE. THIS ACTIVITY IS
EXPECTED TO INCREASE IN COVERAGE AND SPREAD ACRS THE TAF SITES THIS
AFTN THRU ABOUT SUNSET. THE SCATTERED NATURE OF THE ACTIVITY SEEMS
TO WARRANT JUST VCTS MENTIONS FOR NOW. THERE WILL BE PLENTY OF MID
AND UPR LVL MOISTURE LINGERING OVERNIGHT...WITH SOME SHRA/TSRA
POSSIBLE. OVERALL...NOT EXPECTING MUCH FOG/STRATUS
POTENTIAL...EXCEPT IF A SITE IS HIT DIRECTLY BY A SHRA. STILL EXPECT
ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY MORNING...WHICH WARRANTS A
PROB30 AFTER DAYBREAK AT ALL SITES.
OUTLOOK...THE FIRST OF TWO COLD FRONT WILL SWEEP ACROSS THE REGION
ON SATURDAY. THE SECOND COLD FRONT WILL PASS EARLY SUNDAY. SHOWERS
AND THUNDERSTORMS WILL DEVELOP AHEAD OF THESE FRONTS...ESPECIALLY
SATURDAY. DRY WEATHER WILL BEGIN ON MONDAY.
CONFIDENCE TABLE...
19-01Z 01-07Z 07-13Z 13-19Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 91% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...ARK/JAT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
231 PM EDT FRI MAY 10 2013
.SYNOPSIS...
SOUTHWEST FLOW AND MOISTURE WILL INCREASE TODAY THROUGH TONIGHT
AHEAD OF AN APPROACHING COLD FRONT. MOISTURE AND INSTABILITY WILL
LINGER THROUGH SATURDAY AS A SECOND REINFORCING FRONT APPROACHES
FROM THE NORTHWEST. THIS FRONT WILL CROSS THE REGION SUNDAY MORNING
AND USHER IN A DRIER AIRMASS ALONG WITH MUCH COOLER TEMPERATURES.
COOL HIGH PRESSURE WILL LINGER MONDAY THROUGH TUESDAY...WITH
TEMPERATURES REBOUNDING MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 200 PM...A PRE-FRONTAL SHORTWAVE TROF...ASSOCIATED WITH A PAIR
OF MCV/S WILL CROSS THE CWFA THIS EVENING. THE ENVIRONMENT IS FAIRLY
UNSTABLE...WITH SBCAPES IN THE 1000-1500 J/KG...HIGHEST ACRS THE
UPSTATE AND NE GA. DIFFERENTIAL HEATING IN THE MTNS AND ALONG EDGE
OF THE THICKER CIRRUS SHIELD IS HELPING TO INITIATE SCATTERED SHWR
COVERAGE ALREADY EARLY THIS AFTN. THE 16Z HRRR SEEMS TO HAVE THE
CLOSEST IDEA OF THE ACTIVITY COVERAGE...AND IT TAKES IT EWD ACRS THE
CWFA THRU THE REST OF THE AFTN...BRINGING IN THE MORE STABLE MCV AIR
IN FROM THE WEST. THE ENVIRONMENT STILL DOES NOT LOOK ALL THAT
IMPRESSIVE FROM A SEVERE THREAT STANDPOINT. SO WILL CONTINUE TO ONLY
MENTION LGTNG/HVY RAIN IN HWO. AS FOR HYDRO/HVY RAIN THREAT...WITH
THE MOVEMENT OF THE SHORTWAVE AND OVERALL CONVECTION...THINK ANY
AREAS RECEIVING AN INCH OR MORE WITH ONE STORM IS STILL FAIRLY LOW.
MOST AREAS PROBABLY WILL RECEIVE LESS THAN A QUARTER INCH THRU
TONIGHT.
AS COLD FRONT APPROACHES FROM THE WEST...PROFILES ACRS THE CWFA
REMAIN MOIST...WITH PERSISTENT DEEP LAYER WEAK-MOD Q-VECTOR
CONVERGENCE. CONVECTION ALLOWING MODELS DO SHOW MAINLY DEBRIS SHWRS
WITH POTENTIALLY A FEW RUMBLES OF THUNDER OVERNIGHT. THE MAIN
LIMITING FACTOR TO MORE ROBUST CONVECTION/HEAVY RAIN WILL BE ONGOING
CONVECTION ALONG THE GULF COAST...WHICH WILL ROB THE SRN
APPALACHIANS OF THE HIGHER PWAT AIR. WILL CONTINUE WITH 30-40 POP IN
THE PIEDMONT AND 50-60 IN THE MTNS. TEMPS WILL BE ABOVE NORMAL IN
THE MOIST PRE-FRONTAL AIR MASS.
SATURDAY...COLD FRONT AND ASSOCIATED MID LVL SHORTWAVE TROF WILL
CROSS THE AREA DURING THE DAY. LLVL FLOW VEERS TO NEARLY DUE
WESTERLY AHEAD OF THE SFC BNDRY...WITH PWATS DROPPING. WILL CONTINUE
WITH LIKELY POPS IN THE NC ZONES...AND HIGH-END CHC SOUTH. SEVERE
THREAT LOOKS TO STAY EAST WHERE BETTER SHEAR AND INSTBY WILL SET UP.
QPF STILL LOOKS TO BE LIMITED...AS STORMS SHUD HAVE DECENT EWD
MOTION...AND DRY AIR BEGINS TO FILTER IN. TEMPS ARE EXPECTED TO
REACH THE 70S BELOW 3500 FT...TO LWR 80S IN THE LWR PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT FRIDAY...A STRONG UPPER LOW WILL MOVE ACROSS THE
GREAT LAKES STATES SATURDAY NIGHT AND SUNDAY. THIS WILL PUSH A COLD
FRONT ACROSS THE REGION EARLY ON SUNDAY. SATURDAY NIGHT THE UPPER
LEVEL FLOW WILL BACK JUST A BIT AHEAD OF THE ADVANCING UPPER
LOW...THOUGH THE LLVL FLOW WILL REMAIN OUT OF THE WEST TO NORTHWEST.
INSTABILITY WILL BE QUITE LIMITED AFTER MID-EVENING...AND WHILE
THERE WILL BE SOME FORCING FOR SHOWERS AND TSTMS OVER THE EASTERN
ZONES...THE THREAT OF SEVERE WEATHER WILL BE MINIMAL.
BY SUNDAY MORNING A BAND OF LOW TOPPED SHOWERS MAY MOVE INTO THE
MOUNTAINS ALONG THE TRUE COLD FRONT. ANY MEASURE RAINFALL WITH THESE
SHOWERS SHOULD BE CONFINED TO THE IMMEDIATE TENNESSEE BORDER.
SUNDAY WILL BE PLEASANTLY MILD. IT WILL BE BREEZY ACROSS THE
MOUNTAINS AS SKIES CLEAR. AS COOL HIGH PRESSURE BUILDS IN FOR SUNDAY
NIGHT...SOME INTERIOR VALLEYS MAY SEE AREAS OF FROST. AND CERTAIN
HIGH ELEVATIONS COULD EXPERIENCE AN ADVECTIVE FROST. WITH HIGH
PRESSURE STILL BUILDING INTO THE REGION...THERE SHOULD STILL BE
ENOUGH OF FLOW THROUGH THE MAJOR VALLEYS TO KEEP FROST FROM FORMING.
OVERALL...CONFIDENCE IS GOOD THAT SHELTERED VALLEYS WILL SEE SOME
FROST...THOUGH I/M NOT CERTAIN HOW WIDESPREAD IT WILL BE AT THIS
POINT. WE WILL CONTINUE TO MENTION THIS POSSIBILITY IN THE HWO.
MONDAY WILL BE SUNNY AND PLEASANT WITH MAX TEMPS RUNNING ABOUT 10
DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...THE GLOBAL MODELS CONTINUE TO AGREE THAT
THE SHARP UPPER TROUGH AXIS WILL MOVE OFFSHORE MON NIGHT FOLLOWED BY
UPPER RIDGING TUE/WED. THE UPPER RIDGE AXIS WILL CROSS THE FORECAST
AREA WED NIGHT AND THE UPPER PATTERN BECOMES SWLY BY THU WITH A LOW
AMPLITUDE UPPER TROUGH APPROACHING FROM THE WEST. THE TROUGH AXIS
WILL THEN CROSS THE REGION ON FRI.
AT THE SURFACE...COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN
MON NIGHT AND SETTLES OVER THE REGION TUE. TEMPS ON MON NIGHT SHOULD
RUN 10-15 DEGREES BELOW NORMAL WITH FROST/FREEZE POSSIBLE OVER THE
NC MOUNTAINS/VALLEYS. MAX TEMPS ON TUE WILL REBOUND 2 TO 3 DEGREES
BUT STILL LIKELY REMAIN 5-10 DEGREES BELOW NORMAL. TEMPS QUICKLY
WARM UP TO NEAR NORMAL BY WED AFTERNOON AS THE CENTER OF HIGH
PRESSURE MOVES OFFSHORE AND RETURN SWLY FLOW DEVELOPS OVER THE
REGION. THE HIGH WILL REMAIN CENTERED OFF THE ATLANTIC COAST THU
WITH ITS SURFACE RIDGE EXTENDING INTO THE CWA. CONDITIONS LOOK DRY
THROUGH WED AND I/VE MENTIONED 20/30 PERCENT POPS FOR THUNDERSTORMS
LATE THURSDAY...MAINLY IN THE MOUNTAINS DUE TO INCREASING
MOISTURE/BUOYANCY. A SURFACE COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIANS BY THU NIGHT AND TRAVERS THE FORECAST AREA ON FRI.
HOWEVER...MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT MOVES
ACROSS REGION. THEREFORE...I HAVE KEPT POPS IN THE 20 TO 30 PERCENT
RANGE ON FRI. TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL THU/FRI.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A THIN BKN-OVC CIRRUS LAYER HAS STREAMED INTO THE AREA
FROM THE WEST...BUT IS NOT ENUF TO INHIBIT CONVECTIVE CUMULUS TO
DEVELOP TO THE WEST OF THE TERMINAL. SCATTERED SHRA AND A FEW TSRA
ARE EXPECTED TO DEVELOP ACRS THE AREA DURING THE AFTN HOURS. FOR
NOW...WILL GO WITH A TEMPO SHRA DURING THE PEAK HEATING HOURS...AS
TS CHCS TOO LOW ATTM. MAY NEED TO ADD IN TS MENTION...POSSIBLY AS A
TEMPO GROUP WITH A LATER AMD...IF COVERAGE ENDS UP GREATER THAN
EXPECTED. OTHERWISE...SW WINDS ARE GENERALLY 10-15 KTS WITH GUSTS
NEAR 20 KTS. THEY SHUD DIMINISH AROUND SUNSET SLIGHTLY AND LOSE THE
GUSTINESS. THERE WILL BE PLENTY OF MID AND UPR LVL MOISTURE
LINGERING OVERNIGHT...WITH SOME SHRA/TSRA POSSIBLE...ESP IN THE
09Z-12Z TIME FRAME. NOT CONFIDENT ENUF ON TS TO HAVE PROB30
THERE...BUT STILL EXPECT ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY
MORNING...WHICH WARRANTS A PROB30 AFTER 13Z. GUIDANCE NOT INDICATING
ANY RESTRICTIONS...BUT SOME FOG/STRATUS IS POSSIBLE LATE TNGT IF
THERE IS MORE RAINFALL THAN EXPECTED THIS AFTN/EVE.
ELSEWHERE...SCATTERED SHRA HAVE ALREADY DEVELOPED BEFORE THE 18Z TAF
ISSUANCE TO THE WEST OF A KAVL/KGMU/KAND LINE. THIS ACTIVITY IS
EXPECTED TO INCREASE IN COVERAGE AND SPREAD ACRS THE TAF SITES THIS
AFTN THRU ABOUT SUNSET. THE SCATTERED NATURE OF THE ACTIVITY SEEMS
TO WARRANT JUST VCTS MENTIONS FOR NOW. THERE WILL BE PLENTY OF MID
AND UPR LVL MOISTURE LINGERING OVERNIGHT...WITH SOME SHRA/TSRA
POSSIBLE. OVERALL...NOT EXPECTING MUCH FOG/STRATUS
POTENTIAL...EXCEPT IF A SITE IS HIT DIRECTLY BY A SHRA. STILL EXPECT
ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY MORNING...WHICH WARRANTS A
PROB30 AFTER DAYBREAK AT ALL SITES.
OUTLOOK...THE FIRST OF TWO COLD FRONT WILL SWEEP ACROSS THE REGION
ON SATURDAY. THE SECOND COLD FRONT WILL PASS EARLY SUNDAY. SHOWERS
AND THUNDERSTORMS WILL DEVELOP AHEAD OF THESE FRONTS...ESPECIALLY
SATURDAY. DRY WEATHER WILL BEGIN ON MONDAY.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 94% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1249 PM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
TODAY APPEARS A LITTLE QUIETER THEN THE PAST FEW DAYS...AS OUR
STUBBORN UPPER LEVEL LOW IS FINALLY OOZING EAST OF OUR AREA. STILL
HAVE AREAS OF CLOUD COVER TO CONTEND WITH EARLY TODAY. HOWEVER
MOISTURE PROFILES ARE SUCH THAT THERE SHOULD BE A GENERAL CLEARING
THROUGH THE DAY OTHER THEN SOME STRATO CUMULUS POTENTIAL OVER PARTS
OF THE FORECAST AREA WHICH RECEIVED A GOOD WETTING RAINFALL THE PAST
FEW DAYS. BUT AS THE AFTERNOON PROGRESSES...ANY STRATO CUMULUS
POTENTIAL SHOULD DRY UP. WINDS LOOK TO BE FAIRLY LIGHT AHEAD OF
TONIGHTS COLD FRONT. THIS WILL KEEP MIXING POTENTIAL DOWN A BIT...
SO KEPT HIGHS A FEW DEGREES EITHER SIDE OF SEASONAL NORMALS. ONE
THING TO WATCH FOR ARE DEW POINT TEMPERATURES IN OUR FAR WESTERN
ZONES. GUIDANCE DEW POINT VALUES HAVE BEEN CONSISTENTLY TOO HIGH IN
OUR CENTRAL SD ZONES FOR DAYS NOW. DEW POINT READINGS SHOULD RAISE
EARLY TODAY. HOWEVER ONCE THE SURFACE WINDS GO WESTERLY THIS
AFTERNOON AHEAD OF THE COLD FRONT...NOT SURE WHY LOCATIONS AROUND
CHAMBERLAIN WOULD HAVE DEW POINTS IN THE LOWER 40S AS SUGGESTED BY
SOME GUIDANCES. RAP AND HRRR LOOK TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION IN THAT AREA...AND DO INDEED DRY OUT OUR FAR
WESTERN ZONES THIS AFTERNOON. THEREFORE BLENDED THOSE TWO MODELS
INTO SOME OF THE MORE REASONABLE LOOKING CONSENSUS READINGS TO GIVE
DRIER MINIMUM HUMIDITY VALUES IN CENTRAL SD. CONCERNING
PRECIPITATION...AT THE MOMENT IT LOOKS DRY. HOWEVER RIGHT ALONG A
SUBTLE SURFACE CONVERGENCE AXIS WEST OF I 29...MAY NEED TO WATCH FOR
A FEW SPRINKLES OR AN ISOLATED LIGHT SHOWER EARLY TODAY IN THOSE
LOCATIONS.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
COLD FRONT PROGGED TO CROSS THE CWA TONIGHT...ENTERING THE
NORTHWEST PORTION OF OUR CWA BY 03Z AND EXITING NORTHWEST IOWA BY
09Z. BEST LARGE SCALE FORCING AND DEEPER MOISTURE STAYS OFF TO OUR
NORTHEAST. THUS THE GREATEST PRECIP POTENTIAL SHOULD BE NORTHEAST OF
US OVER MINNESOTA...WITH OUR AREA HAVING TO RELY ON ANY CONVECTION
THAT CAN GET GOING. HOWEVER IT IS A DECENT FRONTAL BOUNDARY...WITH
POTENTIALLY JUST ENOUGH LOW TO MID LEVEL THETAE ADVECTION TO INDEED
KICK OFF A FEW SHOWERS...THUS WILL KEEP THE LOW POPS GOING. JUST
ENOUGH INSTABILITY TO MAYBE GET A FEW RUMBLES OF THUNDER AS WELL.
DECENT LOW LEVEL JET OF WINDS BEHIND THE FRONT WITH A QUICK SHOT OF
CAA AS WELL. THUS NOT SURPRISING THAT MODEL SOUNDINGS SHOW THE
OPPORTUNITY FOR A PERIOD OF GUSTY WINDS RIGHT BEHIND THE FRONT
TONIGHT. MAY BE ABLE TO GET SOME 40 MPH GUSTS DOWN TO THE SURFACE
FOR A FEW HOURS FOLLOWING THE FRONTAL BOUNDARY AS WE MIX INTO THE 30
TO 40 KT JET. SO SOMETHING TO KEEP AN EYE ON.
EXPECT WINDS TO DROP OFF SOME SATURDAY MORNING AS MIXING WEAKENS A
BIT AND THE JET PUSHES SOUTHEAST OF THE AREA. HOWEVER AS DEEPER
MIXING BEGINS WITH DAYTIME HEATING WINDS WILL ONCE AGAIN INCREASE.
NORTHERLY WINDS GUSTING 25 TO 35 MPH LOOK LIKELY FROM MID MORNING
INTO THE AFTERNOON HOURS. IT WILL BE A CHILLY ONE TOO...WITH HIGHS
RANGING FROM THE LOW 50S OVER SOUTHWEST MINNESOTA TO AROUND 60 ALONG
THE MISSOURI RIVER. SHOULD AT LEAST BE MOSTLY SUNNY THOUGH...WITH
JUST A FEW AFTERNOON FAIR WEATHER CU. SURFACE HIGH PRESSURE QUICKLY
BUILDS IN SATURDAY NIGHT...WITH IDEAL RADIATIONAL COOLING EXPECTED
OVER MOST OF THE CWA. GIVEN THE COOL LOW LEVEL TEMPERATURE PROFILES
IN PLACE...EXPECTING A COLD NIGHT. WENT AT OR BELOW THE COLDEST
GUIDANCE...WITH UPPER 20S TO LOW 30S OVER MOST OF THE AREA. HOWEVER
IF CURRENT TRENDS PERSIST...WOULD NOT BE SURPRISED TO SEE SOME MID
20S IN SOME OF THE COOLER LOCATIONS EAST OF THE JAMES RIVER.
NEEDLESS TO SAY...LOOKS LIKE FROST OR FREEZE HEADLINES WILL BE
NEEDED FOR MOST OF THE CWA.
THE TROUGH EXITS TO OUR EAST ON SUNDAY...ALLOWING FOR A SLOW WARMUP
TO BEGIN. HIGHS WILL STILL BE BELOW NORMAL THOUGH...WITH UPPER 50S
AND LOW 60S EAST AND UPPER 60S WEST. WINDS WILL BE PRETTY LIGHT AND
THE SUN SHOULD BE SHINING BRIGHT...THUS NOT A BAD DAY OVERALL. OUR
REAL WARMTH BEGINS TO MOVE IN MONDAY AS UPPER RIDGING BUILDS IN.
HIGHS MONDAY A BIT TRICKY...WITH A SHARP GRADIENT LIKELY. AROUND 90
SEEMS ALMOST CERTAIN IN SOUTH CENTRAL SOUTH DAKOTA THOUGH...WITH THE
GREATER UNCERTAINTY TO THE EAST. MODELS BOUNCING AROUND A BIT ON HOW
QUICKLY WARM AIR MOVES IN EAST OF THE JAMES...BUT MID 70S TO MID 80S
LOOK PROBABLE. TUESDAY SHOULD BE THE HOTTEST DAY OF THE YEAR THUS
FAR. MODELS HAVE SLOWED DOWN THE WEAK FRONT...MEANING WE SHOULD GET
THE FULL FORCE OF THE HEAT. 850MB TEMPERATURES ARE QUITE
IMPRESSIVE...RUNNING CLOSE TO THE CLIMATOLOGICAL MAX FOR THIS TIME
OF YEAR. WENT WELL ABOVE ALLBLEND FOR HIGHS...WITH UPPER 80S TO LOW
90S LOOKING LIKE A GOOD BET FOR THE ENTIRE CWA. HOWEVER...IT SEEMS
QUITE POSSIBLE THAT AN AREA OF MID TO UPPER 90S WILL OCCUR IN A
CORRIDOR JUST AHEAD OF THE FRONT. TRYING TO PIN DOWN WHERE THIS WILL
OCCUR IS TOUGH THIS FAR OUT...AS IT COULD REALISTICALLY BE AS FAR
WEST AS CENTRAL SOUTH DAKOTA...OR AS SOUTHEAST AS NORTHWEST IOWA.
THUS DID NOT WANT TO GO TOO HIGH WITH FORECAST MAXES THIS FAR
OUT...GIVEN THE CURRENT FORECAST IS ALREADY 20 DEGREES ABOVE NORMAL.
MODELS DIVERGE A BIT AFTER TUESDAY...BUT GENERAL CONSENSUS IS FOR
THE RIDGE TO FLATTEN AS WAVES TO OUR NORTH PUSH A FRONTAL BOUNDARY
SOUTH THROUGH THE NORTHERN PLAINS. STRENGTH OF THIS BOUNDARY STILL
UNCERTAIN...BUT EITHER WAY IT SHOULD BE COOLER WEDNESDAY AND
THURSDAY...WITH HIGHS EITHER IN THE 70S OR 80S DEPENDING ON FRONTAL
STRENGTH. PRECIP CHANCES TOUGH TO PIN DOWN...OTHER THAN THAT IT
LOOKS LIKE THERE GOOD BE SOME ISOLATED TO SCATTERED CONVECTION
ANYTIME TUESDAY NIGHT ON AS THE WEAK WAVES AND FRONTS PUSH
ACROSS...BUT NOT EXPECTING ANYTHING WIDESPREAD OR SIGNIFICANT AT
THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1249 PM CDT FRI MAY 10 2013
GENERALLY VFR CONDITIONS EXPECTED THROUGH 11/18Z. HOWEVER STRONG
WINDS WILL ARRIVE BEHIND COLD FRONT WITH NORTHWEST WINDS GUSTING
BRIEFLY TO AS HIGH AS 40 KNOTS...THEN 25 TO 30 KNOT GUSTS AFTER
08Z THROUGH 18Z. SCATTERED TSRA POSSIBLE WITH FRONT AS IT CROSSES
AREA FROM THE NORTHWEST 02Z-08Z VERY BRIEF AND LOCAL VISIBILITY
REDUCTIONS TO 3-5SM POSSIBLE IN THUNDERSTORMS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJF
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
322 PM CDT FRI MAY 10 2013
.SHORT TERM...
BAND OF STRONG TO SEVERE THUNDERSTORMS IN THE CONCHO VALLEY
SOUTHWEST INTO CROCKETT COUNTY...ASSOCIATED WITH A COLD
FRONT...WAS STEADILY MOVING SOUTHEAST THIS AFTERNOON. A SEVERE
THUNDERSTORMS WATCH IS IN EFFECT FOR MUCH OF WEST CENTRAL
TEXAS...SOUTH OF THE BIG COUNTRY UNTIL 10 PM CDT TONIGHT. ATMOSPHERE
WAS UNSTABLE THIS AFTERNOON AS COLDER AIR ALOFT...ASSOCIATED WITH
AN UPPER LEVEL TROUGH OVER NEW MEXICO MOVED EAST. SPC RAP SB CAPES
WERE 1500-2500 J/KG. THIS IS LOWER THAN YESTERDAY...BUT STILL
ENOUGH TO GET GOLFBALL SIZE HAIL IN COKE COUNTY FROM A SUPERCELL
HIS AFTERNOON.
SEVERE STORM ACTIVITY SHOULD NOT BE QUITE AS EXTENSIVE AS
YESTERDAY...AND SHOULD WEAKEN BY SUNSET WITH LOSS OF DAYTIME
HEATING AND PASSAGE OF THE COLD FRONT.
STILL KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS SATURDAY AS
THE UPPER TROUGH MOVES ACROSS THE REGION. DRIER AIR WILL ALSO MOVE
IN FROM NORTH TO SOUTH...SO SEVERE THUNDERSTORMS ARE NOT EXPECTED.
MOST STORMS SHOULD BE ALONG THE I-10 CORRIDOR AND END BY LATE
AFTERNOON.
04
.LONG TERM...
SHOWER AND THUNDERSTORM CHANCES RETURN TUESDAY AS A CUT OFF UPPER
LOW OVER BAJA CALIFORNIA MOVES NORTHEAST AND WEAKENS OVER NEW
MEXICO AND THE TEXAS PANHANDLE. MOVEMENT AND PLACEMENT OF CUT OFF
UPPER LOWS HAS ALWAYS BEEN DIFFICULT...ESPECIALLY WHEN THEY KICK
OUT. WILL KEEP POPS FAIRLY LOW AT THIS TIME...IN THE 20 TO 30
PERCENT RANGE...WITH THE HIGHER POPS ALONG THE I-10 CORRIDOR.
THUS IT POSSIBLE THAT THE SYSTEM BEGIN TO MOVE SLOWER THAN
FORECAST...DESPITE FAIRLY GOOD AGREEMENT IN RUN CONTINUITY AND
BETWEEN THE GFS AND EC MODELS. REMOVED POPS BY THURSDAY AS THE
UPPER DISTURBANCE MOVES NE AND AN UPPER RIDGE BUILDS IN.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 80 54 79 58 / 20 10 10 5 5
SAN ANGELO 58 79 54 81 55 / 30 20 10 10 5
JUNCTION 58 77 53 81 53 / 30 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1212 PM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CDT FRI MAY 10 2013
MAIN FORECAST CONCERN IS WITH THE IMPACTS OF A COLD FRONT TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST INTO BRITISH COLUMBIA...A POTENT
SHORTWAVE TROUGH DROPPING INTO CENTRAL SASKATCHEWAN...AND A WEAK
SHORTWAVE TROUGH OVER CENTRAL WISCONSIN. THE LATTER SHORTWAVE TROUGH
WAS RESPONSIBLE FOR THE WET WEATHER YESTERDAY...WHICH LATEST RADAR
IMAGERY STILL SHOWS SCATTERED SHOWERS AND DRIZZLE OVER THE SOUTHEAST
HALF OF THE FORECAST AREA. CLOUDS ASSOCIATED WITH THE SHORTWAVE
ENCOMPASS MUCH OF THE FORECAST AREA...BUT HAVE CLEARED OUT ACROSS
NORTH DAKOTA INTO THE NORTHERN 2/3 OF MINNESOTA AND NORTHWEST WI.
00Z BIS AND ABR SOUNDINGS WERE VERY DRY BELOW 700MB WITH DEWPOINT
DEPRESSIONS OF 15C OR GREATER. THIS DRY AIR WAS ASSOCIATED WITH A
SURFACE RIDGE OF HIGH PRESSURE. A TIGHT PRESSURE GRADIENT AHEAD OF
THE HIGH AND LOW PRESSURE MOVING THROUGH NORTHERN ILLINOIS HAS
RESULTED IN SOME GUSTY NORTHEAST WINDS ACROSS THE FORECAST AREA.
COOLER AIR TOO WITH THE HIGH PRESSURE RIDGE...REFLECTED BY 850MB
TEMPS AT 00Z OF 5-7C FROM BIS TO MPX...COMPARED TO 10C AT DVN. TO
THE NORTHWEST...BEHIND THE POTENT SHORTWAVE TROUGH...MUCH COLDER
AIR EXISTS. -2C 850MB TEMPS WERE OBSERVED AT 00Z OVER NORTHERN
ALBERTA. THE COLD FRONT ASSOCIATED WITH THE TROUGH WAS IN SOUTHEAST
SASKATCHEWAN.
THE HIGH PRESSURE RIDGE AND ITS DRY AIR ARE FORECAST TO MOVE INTO
THE CWA THROUGH THE DAY...WITH THE RIDGE OVERHEAD AT 00Z. THUS...WE
WILL SEE GRADUAL CLEARING NORTHWEST TO SOUTHEAST THROUGH THE DAY.
MAY STILL HAVE TO CONTEND WITH SOME LINGERING SHOWERS TOO IN THE
SOUTHEAST SECTION OF THE FORECAST AREA UNTIL 15Z. TEMPERATURES ARE
LIKELY TO STRUGGLE TO RISE THIS MORNING WITH COLD ADVECTION AND
CLOUDS IN PLACE...BUT SHOULD BE ABLE TO CLIMB INTO THE LOW TO MID
60S BY LATE IN THE DAY WITH THE SUN AND 850MB TEMPS OF 4-5C.
MODELS ARE IN GOOD AGREEMENT TAKING THE POTENT SHORTWAVE TROUGH
OVER CENTRAL SASKATCHEWAN INTO NORTHWEST ONTARIO TONIGHT...WITH
ANOTHER STRONG SHORTWAVE DIGGING IN BEHIND IT INTO CENTRAL MINNESOTA
BY 12Z SATURDAY. THE 500MB HEIGHT FALLS ARE QUITE IMPRESSIVE BETWEEN
00-12Z...FROM AROUND 100 METERS ALONG I-90 TO ALMOST 200 METERS OVER
WESTERN LAKE SUPERIOR. NEEDLESS TO SAY...PLENTY OF DYNAMIC FORCING.
ONE HUGE PROBLEM IS THE LACK OF MOISTURE... ESPECIALLY AHEAD OF THE
TROUGH PER THE 00Z BIS SOUNDING. THUS...NO PRECIPITATION WILL OCCUR
AHEAD OF THE COLD FRONT ACCOMPANYING THE TROUGH...WHICH IS PROGGED
TO CROSS THE AREA BETWEEN 06-12Z. IF PRECIPITATION OCCURS...IT HAS
TO OCCUR THEN POST-FRONTAL...IN THE COOLER AIR. CROSS-SECTIONS SHOW
A FAIRLY STRONG LOW LEVEL FRONTOGENESIS-FRONTOLYSIS COUPLET...ALONG
WITH SOME NEGATIVE EPV BEING INGESTED INTO THIS CIRCULATION. WITH
ALL THE FORCING PRESENT...HAVE TO IMAGINE A NARROW BAND OF SHOWERS
COMING THROUGH BEHIND THE FRONT. THERE MAY EVEN BE A RUMBLE OR TWO
OF THUNDER GIVEN THE NEGATIVE EPV SIGNAL...BUT THE CHANCE AND
COVERAGE IS TOO LOW TO MENTION. EXPECT WINDS TOO TO RAPIDLY INCREASE
OUT OF THE NORTHWEST BEHIND THE FRONT...AIDED BY ISALLOBARIC
FORCING. SOME PLACES...LIKE ROCHESTER AND DODGE CENTER...COULD GUST
CLOSE TO WIND ADVISORY...ESPECIALLY WITH THE SHOWERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 327 AM CDT FRI MAY 10 2013
DEEP TROUGHING IS PROGGED TO PERSIST OVER THE GREAT LAKES MUCH OF
THE WEEKEND...RESULTING FROM THE POTENT SHORTWAVE TROUGH DIGGING
TOWARDS THE AREA TONIGHT. 500MB STANDARDIZED ANOMALIES ARE 1.5-2
BELOW NORMAL ALONG WITH 850MB ANOMALIES OF 2 BELOW NORMAL. THESE LOW
ANOMALIES RESULT IN A VARIETY OF ISSUES:
1. TEMPERATURES. CHILLY HIGHS AND LOWS ARE LIKELY...AND COULD GET
CLOSE TO RECORDS SOLELY BASED ON THE 850MB ANOMALIES. LA CROSSE
RECORD LOWS ARE AROUND 30 WHILE ROCHESTER IS AROUND 26. THE BIGGEST
PROBLEM WITH TEMPERATURES ARE THE WINDS. CONTINUOUS COLD ADVECTION
THROUGH SATURDAY NIGHT WILL HELP KEEP THE BOUNDARY LAYER MIXED...AND
WITH 925MB WINDS STILL AT 20-25 KT AT 12Z SUNDAY...EXPECTING
DIFFICULT CONDITIONS TO DECOUPLE. BETTER SHOT OF DECOUPLING TAKES
PLACE SUNDAY EVENING...BUT WARM ADVECTION TAKES HOLD AFTER
MIDNIGHT. FOR NOW HAVE TAKEN A BLEND OF MOS AND RAW MODEL GUIDANCE
FOR HIGHS AND LOWS...GIVEN THE UNCERTAINTY ON DECOUPLING.
2. WINDS...STRONG SUBSIDENCE FLOWS INTO THE AREA ON SATURDAY WILL
COMBINE WITH LOW LEVEL UNIDIRECTIONAL NORTHWEST FLOW...THE STRONG
MIXING FROM THE MAY SUN...AND COLD ADVECTION TO RESULT IN A BLUSTERY
DAY. WE COULD MIX TO 775 MB OR HIGHER. MOMENTUM TRANSFER OF THE
WINDS AT THAT LEVEL OF 40-45 KT RESULTS IN GUSTS OF 30-35 KT AT THE
SURFACE...JUST BELOW ADVISORY CRITERIA. WINDS SLOWLY DIMINISH
SATURDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE
PLAINS.
3. FROST/FREEZE. CONNECTING WITH THE TEMPERATURES AND WINDS ABOVE...
FROST LOOKS VERY DIFFICULT TO FORM SATURDAY NIGHT. ADDITIONALLY...
RELATIVE HUMIDITIES MAY NOT EXCEED 80 PERCENT DUE TO DRY ADVECTION.
IF ANYTHING...THE CONCERN WOULD COME FROM A FREEZE DUE TO THE
TEMPERATURES...IF THEY FALL BELOW FREEZING. BETTER SHOT OF FROST
WOULD COME SUNDAY NIGHT...DEPENDING ON WHEN HIGH CLOUDS AND THE WARM
AIR SPREADS IN. FROST LOOKS MOST LIKELY IN CENTRAL WISCONSIN.
4. PRECIPITATION...COLD POOL OF 500MB TEMPS OF -30C LOOKS TO CROSS
TAYLOR COUNTY MID-DAY SATURDAY. DAYTIME MIXING COMBINED WITH THE
MOISTURE WITH THIS COLD POOL COULD GENERATE A FEW SHOWERS ACROSS
TAYLOR/CLARK COUNTIES. HAVE KEPT 20 PERCENT CHANCES GOING FOR THESE.
OTHERWISE...DRY CONDITIONS EXPECTED TO PREVAIL.
FOR NEXT WEEK...THE BIG HIGHLIGHT IS TUESDAY AND WEDNESDAY WITH A
CONSISTENTLY SHOWN STRONG SURGE OF WARM AIR. THERE IS VERY STRONG
MODEL AGREEMENT OF TROUGHING COMING INTO THE PACIFIC NORTHWEST EARLY
NEXT WEEK...SHOVING A RIDGE TOWARDS THE FORECAST AREA. A LOW
POTENTIAL EXISTS FOR SOME SHOWERS AND THUNDERSTORMS AS THE RIDGE
APPROACHES MONDAY AFTERNOON INTO MONDAY NIGHT. HEADING INTO
TUESDAY...850MB STANDARDIZED ANOMALIES JUMP TO 2-2.5 ABOVE...
SUGGESTING POTENTIAL RECORD HIGHS. THERE ARE TWO ISSUES ON TUESDAY
TO CONTEND WITH...TIMING OF THE SURFACE WARM FRONT AND HOW DRY THE
AIR IS IN THE WAKE OF THE FRONT. THE 09.12Z/10.00Z GFS WERE IN GREAT
AGREEMENT PUSHING THE WARM FRONT THROUGH THE AREA ON TUESDAY...
LIKELY RESULTING IN HIGHS IN THE 80S TO POSSIBLY LOW 90S.
HOWEVER...THE 10.00Z ECMWF/CANADIAN ONLY GET THE WARM FRONT TO THE
MISSISSIPPI RIVER. WITH 850MB TEMPS OF 20C+ IN THE WAKE OF THE
FRONT...TIMING OF THE FRONT IS CRITICAL. ON THE MOISTURE SIDE...THE
GFS AND ECMWF WANT TO BRING DEWPOINTS UP INTO THE 60S...BUT THIS
SEEMS WAY TOO HIGH GIVEN THE LACK OF CORN CROPS TO THE SOUTH AND THE
WARM SURGE BEING OF ROCKIES ORIGIN. THUS...DEEPER MIXING IS LIKELY
BEHIND THE FRONT. NEXT CONCERN IS WHEN DOES A COLD FRONT COME
THROUGH. THE 10.00Z ECMWF/CANADIAN REALLY SLOWED THIS DOWN...NOT
CROSSING TIL THURSDAY. IF THIS COMES TRUE...HIGHS WEDNESDAY
COULD TOUCH 90. ON THE OTHER HAND...A FASTER FRONT FROM THE 10.00Z
GFS WOULD KEEP HIGHS IN THE 70S. SPLIT THE DIFFERENCE FOR HIGHS ON
WEDNESDAY FOR NOW. ALSO...MAINTAINED A 20-30 PERCENT CHANCE FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH THURSDAY FOR THE
FRONT...WITH WEDNESDAYS CHANCES IN CASE THE FRONT ENDS UP BEING
FASTER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1211 PM CDT FRI MAY 10 2013
CLOUDS BEHIND THE COLD FRONT HAVE CLEARED BOTH TAF SITES FOR THE
MOST PART. ONE LAST AREA OF CLOUDS COULD ROTATE BACK ACROSS KLSE
EARLY THIS AFTERNOON FOR A SHORT PERIOD OF SOME VFR CEILINGS.
AFTER THAT...WEAK HIGH PRESSURE WILL QUICKLY MOVE ACROSS THIS
EVENING FOR A PERIOD OF VFR WEATHER. THE NEXT COLD FRONT IS
ALREADY MOVING SOUTHEAST ACROSS THE DAKOTAS. BASED ON THE 10.12Z
NAM AND 10.06Z HI-RES ARW...THIS FRONT WILL MOVE QUICKLY ACROSS
BOTH TAF SITES IN THE 09Z TO 12Z WINDOW. THE BEST FORCING WITH THE
COLD FRONT APPEARS TO BE NORTHEAST OF THE TAF SITES SO MAINLY
EXPECTING THE POSSIBILITY OF SCATTERED SHOWERS ALONG AND BEHIND
THE FRONT FOR THE TAF SITES. HAVE SHOWN A THREE HOUR WINDOW IN A
TEMPO GROUP WHERE THE BEST CHANCE FOR SOME SHOWERS SHOULD BE ALONG
WITH MVFR CEILINGS. THE OTHER ISSUE BEHIND THE FRONT WILL BE THE
NORTHWEST WINDS. STRONG LOW LEVEL LAPSE RATES OF 7-9 C/KM DEVELOP
QUICKLY BELOW 750 MB ONCE THE FRONT PASSES THROUGH. THIS WILL
ALLOW FOR DEEP MIXING TO DEVELOP TO PRODUCE GUSTY NORTHWEST WINDS.
SUSTAINED SPEEDS SHOULD INCREASE TO AROUND 20 KNOTS BY MID MORNING
WITH GUSTS TO AROUND 30 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04