AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
920 AM PDT FRI JUL 4 2008
.SYNOPSIS...
A SHALLOW MARINE LAYER WILL CONTINUE COASTAL LOW CLOUDS AND FOG
DURING THE NIGHTS AND MORNINGS. OTHERWISE...UPPER LEVEL HIGH
PRESSURE WILL KEEP THE WEATHER FAIR WITH WARM TO HOT DAYS INLAND.
A SMALL AMOUNT OF MID LEVEL MOISTURE WILL BRING SOME CLOUDS TO THE
MOUNTAINS THIS AFTERNOON WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER
THE SAN DIEGO COUNTY MOUNTAINS.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
EARTH REACHED APHELION OR FARTHEST POINT FROM THE SUN IN ITS ORBIT
AROUND THE SUN...DISTANCE 94.5 MILLION MILES...AROUND 08Z TODAY.
MARINE LAYER WAS QUITE SHALLOW THIS MORNING. MDCRS SOUNDING FROM A
DEPARTURE OF ORANGE COUNTY JOHN WAYNE AIRPORT SHOW THE DEPTH AT
AROUND 280 FEET. STRATUS/FOG IS CONFINED TO THE IMMEDIATE COAST AT
THIS TIME. AN OUTFLOW BOUNDRY FROM THUNDERSTORMS OVER ARIZONA
OVERNIGHT APPEARS TO HAVE SQUASHED DOWN THE MARINE LAYER RESULTING
IN LIMITED STRATUS ALONG THE COAST. ANOTHER OUTFLOW BOUNDRY IS JUST
MOVING OVER THE EASTERN DESERT AREAS OF OUR CWA AT THIS TIME BUT
APPEARS TO BE FADING AWAY AS IT MOVES WEST. THIS COULD TRIGGER SOME
CONVECTION OVER THE SAN DIEGO MOUNTAINS LATER THIS MORNING OR
AFTERNOON BUT EXPECT IF ANYTHING DEVELOPS WILL BE ISOLATED.
LOW LEVEL MOISTURE FROM A GULF SURGE REMAINS OVER THE SOUTHERN
DESERTS WITH DEW POINTS NEAR 70 F OR GREATER. MADE SOME ADJUSTMENTS
TO THE DEW POINTS FOR THE DESERT AREAS FOR THE MORNINGS THROUGH THE
WEEKEND TO TAKE INTO ACCOUNT THE GULF SURGES.
12Z NAM SHOWS THE AREA IN A CULL BETWEEN THE RIDGE OFFSHORE AND THE
ONE TO THE EAST. DESERT AREAS EAST OF OUR CWA ARE MOSTLY IN THE
SOUTH TO SOUTHEASTERLY FLOW WHERE AS AREAS ALONG THE COAST AND
FURTHER WEST ARE IN A NORTHWEST TO NORTH FLOW. THIS CONTINUES
THROUGH THE WEEKEND WHICH SHOULD LIMIT ANY CONVECTION OVER THE
MOUNTAINS. SHOULD THE SOUTHERLY FLOW PUSH WESTWARD OVER THE
MOUNTAINS...CONVECTION WOULD BE MORE WIDESPREAD. MODELS CONTINUE TO
SHOW A FAIRLY SIGNIFICANT AMOUNT OF MID LEVEL MOISTURE OVER THE AREA
TODAY THROUGH SATURDAY THEN FADING AWAY ON SUNDAY.
IN THE LONGER RANGE...ECMWF MODEL IS MORE BULLISH ON MOISTURE LATE
IN THE COMING WEEK INTO NEXT WEEKEND OVER THE AREA THAN THE GFS
MODEL. THE GFS MODEL DOES SHOW SOME MOISTURE BUT NOT AS DEEP. AT
THIS TIME WILL LEAN TOWARDS JUST PARTLY CLOUDY FOR THE MOUNTAINS FOR
THAT PERIOD. OTHERWISE CONTINUED DRY THROUGH THE PERIOD.
CURRENT FORECASTS LOOK GOOD SO NO UPDATES ARE PLANNED AT THIS TIME.
&&
.AVIATION...
041600Z...SHALLOW MARINE LAYER BELOW 1000 FT. LOW STRATUS AND FOG
MAINLY CONFINED NEAR THE IMMEDIATE COAST AND BEACHES THIS MORNING.
BASES BELOW 500 FT MSL WITH 3-5SM MVFR VISIBILITY...AND LOCAL 1SM OR
LESS IN FOG/HAZE EARLY MORN. EXPECT GRADUAL CLEARING NEAR THE
BEACHES THRU EARLY THIS AFTN WITH SOME LINGERING MVFR HAZE. FOR
TONIGHT AREAS OF STRATUS AND PATCHY FOG WILL START TO REFORM MAINLY
AFTER 06Z NEAR THE COAST AND REACH 5-10 MILES INLAND BY 13Z SAT.
ABOVE THE MARINE LAYER...UNRESTRICTED VISIBILITIES WILL CONTINUE
TODAY THROUGH TONIGHT. SOME AFTERNOON CUMULUS OVER THE MOUNTAINS
WITH BASES AROUND FL100.
MAX TEMPERATURES TODAY FOR KPSP/KTRM FROM 41-44C...KSNA 25-28C.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...HORTON
AVIATION/MARINE...LAVIS
NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS MIAMI FL
1035 AM EDT FRI JUL 4 2008
.UPDATE...12Z MIA SOUNDING TODAY SHOWS SLIGHTLY MORE STABLE
CONDITIONS THAN 24 HRS AGO (THURSDAY) WITH WARMER 500 MB TEMPS AND
LOWER CAPE (AFTER A MODIFIED SOUNDING FOR AFTERNOON CONDITIONS) BUT
STILL UNSTABLE ENOUGH TO RESULT IN SHWRS/TSTMS DEVELOPING OVER THE
AREA DURING AFTERNOON HOURS. IN FACT K INDEX IS HIGHER, WHICH COULD
INDICATE SCT TO NMRS DEVELOPMENT. HOWEVER, THE POTENTIAL FOR STRONG
MICROBURSTS IS SLIGHTLY LOWER THAN YESTERDAY`S AS THERE IS NO REAL
(ACTUALLY SMALLER AREA) ELEVATED SOURCE OF DRY AIR. LOCAL
CALCULATIONS SUGGEST MAX DOWNDRAFT POTENTIAL OF 30 TO 40 MPH, BUT
WILL STRETCH IT A LITTLE BIT AND KEEP THE MENTIONING OF GUSTS UP TO
50 TO 55 MPH IN THE HWO WITH THE STRONGEST STORMS THAT DEVELOP THIS
AFTERNOON. PW VALUE IS HIGHER TODAY (1.82 INCHES) AND EXPECTED STORM
MOTION SLIGHTLY SLOWER, SO WL EXPECT LOCALLY HEAVY DOWNPOURS WITH
ANY STORM. SINCE THE LOW LVL FLOW IS MAINLY ESE, THIS WILL TEND TO
KEEP INITIAL CONVECTIVE ACTIVITY AWAY FROM THE ERN METRO AREAS IN
BROWARD/MIAMI-DADE, BUT THE MEAN STEERING FLOW WILL STILL PUSH THE
STORMS SLOWLY NORTHEAST, ONCE THEY DEVELOP. WEST COAST SEA BREEZE
MAY DEVELOP AGAIN AND KEEP STORMS EAST OF NAPLES METRO AREA, THUS
LOWER POPS ARE INDICATED FOR NAPLES. CURRENT FORECAST PACKAGE CALLS
FOR SCT TO LIKELY POPS, ESPECIALLY ACROSS THE INTERIOR, AND THE
CURRENT HWO CALLS FOR A FEW STRONG STORMS, THEREFORE, CHANGES ARE
NOT NEEDED AT THIS TIME.
RGH
.AVIATION...
THE CONTINUING PRESENCE OF THE UPPER LEVEL TROUGH IN THE GULF WILL
HELP TO ENHANCE CONVECTION THIS AFTERNOON. WEAK LOW LEVEL EASTERLY FLOW
WILL ALLOW SHOWERS/TSTORMS TO FORM INLAND ALONG THE EAST COAST IN THE EARLY
AFTERNOON...WITH WESTERLY STEERING FLOW BRINGING THE CONVECTION IN
THE VICINITY OF OR ACROSS THE EAST COAST TERMINALS LATER IN THE
AFTERNOON AND EARLY EVENING. TERMINAL KAPF SHOULD ALSO BE IMPACTED
BY THUNDERSTORM ACTIVITY THIS AFTERNOON. ALL TERMINALS MAY
EXPERIENCE PERIODS OF MVFR CONDITIONS...WITH IFR CONDITIONS
POSSIBLE IN BRIEF PERIODS.
&&
.PREV DISCUSSION... /ISSUED 451 AM EDT FRI JUL 4 2008/
DISCUSSION...THIS INDEPENDENCE DAY IS EXPECTED TO FEATURE VERY
SIMILAR WEATHER CONDITIONS AS WERE EXPERIENCED YESTERDAY. SURFACE
RIDGE OF HIGH PRESSURE OVER SOUTH CENTRAL FL WILL ALLOW FOR A
PREVAILING E-SE LOW LEVEL WIND FLOW...BUT SLIGHTLY VEERED CLOSER
TO THE RIDGE AXIS ACROSS THE LAKE REGION TO PALM BEACH COUNTY.
FLOW WILL BE LIGHT ENOUGH TO ALLOW FOR SEA BREEZES TO PUSH INLAND
AT BOTH COASTS. THE RESULT IS AN EXPECTATION OF CONVECTION
FOCUSING ACROSS INLAND AREAS THIS AFTERNOON. FOLLOWED VERY CLOSELY
TO THE WRF-NMM MODEL WHICH HAS HAD AN EXCELLENT HANDLE ON
GENERAL PLACEMENT OF CONVECTION LATELY. THIS MODEL SHOWS THE EAST
COAST SEA BREEZE BECOMING WELL ESTABLISHED LATE IN THE
DAY...LEAVING CONDITIONS DRY ACROSS THE EAST COAST METRO AREAS
FROM LATE AFTERNOON THROUGH THE NIGHT...BODING WELL FOR FIREWORK
DISPLAYS. CONVECTION WILL WANE THIS EVENING OVER THE WESTERN HALF
OF THE AREA...AND MUCH OF IT SHOULD BE DISSIPATED IN TIME FOR
FIREWORKS.
AN INCOMING SHORTWAVE TROUGH OVER THE NE GULF WILL MOVE ACROSS
THE AREA DURING PEAK HEATING. THESE CAN BE TROUBLE MAKERS IN FLA
IN THE SUMMERTIME. NO ACARS SOUNDINGS ARE CURRENTLY AVAILABLE
ACROSS FL EARLY THIS MORNING...BUT FCST SOUNDINGS FROM BOTH THE
GFS AND NAM SHOW WARMING MID LEVELS WITH WEAKER LAPSE RATES...AS
WELL AS AN ABSENT OF A GOOD DRY LAYER. THEREFORE...WILL DEPICT
ONLY STRONG STORMS IN THE HAZARDOUS WEATHER OUTLOOK ATTM. DAY
SHIFT CAN BETTER ASSESS IF THERE IS ANY SEVERE POTENTIAL WITH THE
12Z SOUNDINGS. AGAIN...FOCUS FOR STORMS IS EXPECTED TO BE INLAND
AWAY FROM BOTH COASTS.
THE RIDGE WILL MOVE INTO NORTH FLORIDA BY SUNDAY...THEN REMAIN
THERE THROUGH EARLY NEXT WEEK...POSSIBLY MOVING BACK SOUTH MID
WEEK...BUT STILL IT LOOKS TO RESIDE NORTH OF THE LOCAL AREA
THROUGH THE PERIOD. THIS WILL MAINTAIN A PREVAILING E-SE WIND
FLOW WITH FOCUS OF CONVECTION BEING ACROSS INTERIOR/GULF COASTAL
LOCALES. ONLY SIGNIFICANT CHANGES TO LATER PERIODS IN THE FCST WAS
TO INCREASE POPS FOR LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT.
GFS...NAM...AND THE ECMWF ALL SHOW A LOW LEVEL TROUGH MOVING
ACROSS THE AREA ON SUNDAY FROM THE SOUTHEAST...WITH INCREASING
CONVERGENCE/MOISTURE...PWATS CLIMBING ABOVE 2 INCHES. GFS/NAM
SHOW LIKELY POPS...AND CANNOT ARGUE WITH THIS...SO INCREASED POPS
TO LIKELY ALL AREAS FOR SUNDAY. ALTHOUGH FLOW WILL BE
E-SE...EXPECT SHRA/TSRA TO MOVE ONSHORE THE EAST COAST...SO
ANYWHERE IS PRONE TO NUMEROUS SHRA/TSRA ON SUNDAY. REST OF PERIOD
SHOULD FEATURE A TYPICAL SUMMERTIME PATTERN OF MAINLY AFTERNOON
CONVECTION...WITH FOCUS INTERIOR/GULF COAST.
MARINE...WINDS LESS THAN 15 KT AND SEAS 4 FT OR LESS WILL PREVAIL
THROUGH THE PERIOD. PREVAILING WINDS WILL BE FROM THE E-SE.
FIRE WEATHER...NO CONCERNS DUE TO HIGH MOISTURE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 74 89 76 / 50 20 40 40
FORT LAUDERDALE 88 78 87 77 / 40 20 40 40
MIAMI 89 78 88 76 / 40 20 40 40
NAPLES 90 73 90 73 / 40 30 60 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
LONG TERM...04/AT
SHORT TERM/AVIATION...04/AT
AREA FORECAST DISCUSSION
NWS MIAMI FL
812 AM EDT FRI JUL 4 2008
.AVIATION...
THE CONTINUING PRESENCE OF THE UPPER LEVEL TROUGH IN THE GULF WILL
HELP TO ENHANCE CONVECTION THIS AFTERNOON. WEAK LOW LEVEL EASTERLY FLOW
WILL ALLOW SHOWERS/TSTORMS TO FORM INLAND ALONG THE EAST COAST IN THE EARLY
AFTERNOON...WITH WESTERLY STEERING FLOW BRINGING THE CONVECTION IN
THE VICINITY OF OR ACROSS THE EAST COAST TERMINALS LATER IN THE
AFTERNOON AND EARLY EVENING. TERMINAL KAPF SHOULD ALSO BE IMPACTED
BY THUNDERSTORM ACTIVITY THIS AFTERNOON. ALL TERMINALS MAY
EXPERIENCE PERIODS OF MVFR CONDITIONS...WITH IFR CONDITIONS
POSSIBLE IN BRIEF PERIODS.
&&
.PREV DISCUSSION... /ISSUED 451 AM EDT FRI JUL 4 2008/
DISCUSSION...THIS INDEPENDENCE DAY IS EXPECTED TO FEATURE VERY
SIMILAR WEATHER CONDITIONS AS WERE EXPERIENCED YESTERDAY. SURFACE
RIDGE OF HIGH PRESSURE OVER SOUTH CENTRAL FL WILL ALLOW FOR A
PREVAILING E-SE LOW LEVEL WIND FLOW...BUT SLIGHTLY VEERED CLOSER
TO THE RIDGE AXIS ACROSS THE LAKE REGION TO PALM BEACH COUNTY.
FLOW WILL BE LIGHT ENOUGH TO ALLOW FOR SEA BREEZES TO PUSH INLAND
AT BOTH COASTS. THE RESULT IS AN EXPECTATION OF CONVECTION
FOCUSING ACROSS INLAND AREAS THIS AFTERNOON. FOLLOWED VERY CLOSELY
TO THE WRF-NMM MODEL WHICH HAS HAD AN EXCELLENT HANDLE ON
GENERAL PLACEMENT OF CONVECTION LATELY. THIS MODEL SHOWS THE EAST
COAST SEA BREEZE BECOMING WELL ESTABLISHED LATE IN THE
DAY...LEAVING CONDITIONS DRY ACROSS THE EAST COAST METRO AREAS
FROM LATE AFTERNOON THROUGH THE NIGHT...BODING WELL FOR FIREWORK
DISPLAYS. CONVECTION WILL WANE THIS EVENING OVER THE WESTERN HALF
OF THE AREA...AND MUCH OF IT SHOULD BE DISSIPATED IN TIME FOR
FIREWORKS.
AN INCOMING SHORTWAVE TROUGH OVER THE NE GULF WILL MOVE ACROSS
THE AREA DURING PEAK HEATING. THESE CAN BE TROUBLE MAKERS IN FLA
IN THE SUMMERTIME. NO ACARS SOUNDINGS ARE CURRENTLY AVAILABLE
ACROSS FL EARLY THIS MORNING...BUT FCST SOUNDINGS FROM BOTH THE
GFS AND NAM SHOW WARMING MID LEVELS WITH WEAKER LAPSE RATES...AS
WELL AS AN ABSENT OF A GOOD DRY LAYER. THEREFORE...WILL DEPICT
ONLY STRONG STORMS IN THE HAZARDOUS WEATHER OUTLOOK ATTM. DAY
SHIFT CAN BETTER ASSESS IF THERE IS ANY SEVERE POTENTIAL WITH THE
12Z SOUNDINGS. AGAIN...FOCUS FOR STORMS IS EXPECTED TO BE INLAND
AWAY FROM BOTH COASTS.
THE RIDGE WILL MOVE INTO NORTH FLORIDA BY SUNDAY...THEN REMAIN
THERE THROUGH EARLY NEXT WEEK...POSSIBLY MOVING BACK SOUTH MID
WEEK...BUT STILL IT LOOKS TO RESIDE NORTH OF THE LOCAL AREA
THROUGH THE PERIOD. THIS WILL MAINTAIN A PREVAILING E-SE WIND
FLOW WITH FOCUS OF CONVECTION BEING ACROSS INTERIOR/GULF COASTAL
LOCALES. ONLY SIGNIFICANT CHANGES TO LATER PERIODS IN THE FCST WAS
TO INCREASE POPS FOR LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT.
GFS...NAM...AND THE ECMWF ALL SHOW A LOW LEVEL TROUGH MOVING
ACROSS THE AREA ON SUNDAY FROM THE SOUTHEAST...WITH INCREASING
CONVERGENCE/MOISTURE...PWATS CLIMBING ABOVE 2 INCHES. GFS/NAM
SHOW LIKELY POPS...AND CANNOT ARGUE WITH THIS...SO INCREASED POPS
TO LIKELY ALL AREAS FOR SUNDAY. ALTHOUGH FLOW WILL BE
E-SE...EXPECT SHRA/TSRA TO MOVE ONSHORE THE EAST COAST...SO
ANYWHERE IS PRONE TO NUMEROUS SHRA/TSRA ON SUNDAY. REST OF PERIOD
SHOULD FEATURE A TYPICAL SUMMERTIME PATTERN OF MAINLY AFTERNOON
CONVECTION...WITH FOCUS INTERIOR/GULF COAST.
MARINE...WINDS LESS THAN 15 KT AND SEAS 4 FT OR LESS WILL PREVAIL
THROUGH THE PERIOD. PREVAILING WINDS WILL BE FROM THE E-SE.
FIRE WEATHER...NO CONCERNS DUE TO HIGH MOISTURE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 74 89 76 / 50 20 40 40
FORT LAUDERDALE 88 78 87 77 / 40 20 40 40
MIAMI 89 78 88 76 / 40 20 40 40
NAPLES 90 73 90 73 / 40 30 60 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
LONG TERM...04/AT
SHORT TERM/AVIATION...04/AT
AREA FORECAST DISCUSSION
NWS MIAMI FL
451 AM EDT FRI JUL 4 2008
.DISCUSSION...THIS INDEPENDENCE DAY IS EXPECTED TO FEATURE VERY
SIMILAR WEATHER CONDITIONS AS WERE EXPERIENCED YESTERDAY. SURFACE
RIDGE OF HIGH PRESSURE OVER SOUTH CENTRAL FL WILL ALLOW FOR A
PREVAILING E-SE LOW LEVEL WIND FLOW...BUT SLIGHTLY VEERED CLOSER
TO THE RIDGE AXIS ACROSS THE LAKE REGION TO PALM BEACH COUNTY.
FLOW WILL BE LIGHT ENOUGH TO ALLOW FOR SEA BREEZES TO PUSH INLAND
AT BOTH COASTS. THE RESULT IS AN EXPECTATION OF CONVECTION
FOCUSING ACROSS INLAND AREAS THIS AFTERNOON. FOLLOWED VERY CLOSELY
TO THE WRF-NMM MODEL WHICH HAS HAD AN EXCELLENT HANDLE ON
GENERAL PLACEMENT OF CONVECTION LATELY. THIS MODEL SHOWS THE EAST
COAST SEA BREEZE BECOMING WELL ESTABLISHED LATE IN THE
DAY...LEAVING CONDITIONS DRY ACROSS THE EAST COAST METRO AREAS
FROM LATE AFTERNOON THROUGH THE NIGHT...BODING WELL FOR FIREWORK
DISPLAYS. CONVECTION WILL WANE THIS EVENING OVER THE WESTERN HALF
OF THE AREA...AND MUCH OF IT SHOULD BE DISSIPATED IN TIME FOR
FIREWORKS.
AN INCOMING SHORTWAVE TROUGH OVER THE NE GULF WILL MOVE ACROSS
THE AREA DURING PEAK HEATING. THESE CAN BE TROUBLE MAKERS IN FLA
IN THE SUMMERTIME. NO ACARS SOUNDINGS ARE CURRENTLY AVAILABLE
ACROSS FL EARLY THIS MORNING...BUT FCST SOUNDINGS FROM BOTH THE
GFS AND NAM SHOW WARMING MID LEVELS WITH WEAKER LAPSE RATES...AS
WELL AS AN ABSENT OF A GOOD DRY LAYER. THEREFORE...WILL DEPICT
ONLY STRONG STORMS IN THE HAZARDOUS WEATHER OUTLOOK ATTM. DAY
SHIFT CAN BETTER ASSESS IF THERE IS ANY SEVERE POTENTIAL WITH THE
12Z SOUNDINGS. AGAIN...FOCUS FOR STORMS IS EXPECTED TO BE INLAND
AWAY FROM BOTH COASTS.
THE RIDGE WILL MOVE INTO NORTH FLORIDA BY SUNDAY...THEN REMAIN
THERE THROUGH EARLY NEXT WEEK...POSSIBLY MOVING BACK SOUTH MID
WEEK...BUT STILL IT LOOKS TO RESIDE NORTH OF THE LOCAL AREA
THROUGH THE PERIOD. THIS WILL MAINTAIN A PREVAILING E-SE WIND
FLOW WITH FOCUS OF CONVECTION BEING ACROSS INTERIOR/GULF COASTAL
LOCALES. ONLY SIGNIFICANT CHANGES TO LATER PERIODS IN THE FCST WAS
TO INCREASE POPS FOR LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT.
GFS...NAM...AND THE ECMWF ALL SHOW A LOW LEVEL TROUGH MOVING
ACROSS THE AREA ON SUNDAY FROM THE SOUTHEAST...WITH INCREASING
CONVERGENCE/MOISTURE...PWATS CLIMBING ABOVE 2 INCHES. GFS/NAM
SHOW LIKELY POPS...AND CANNOT ARGUE WITH THIS...SO INCREASED POPS
TO LIKELY ALL AREAS FOR SUNDAY. ALTHOUGH FLOW WILL BE
E-SE...EXPECT SHRA/TSRA TO MOVE ONSHORE THE EAST COAST...SO
ANYWHERE IS PRONE TO NUMEROUS SHRA/TSRA ON SUNDAY. REST OF PERIOD
SHOULD FEATURE A TYPICAL SUMMERTIME PATTERN OF MAINLY AFTERNOON
CONVECTION...WITH FOCUS INTERIOR/GULF COAST.
&&
.MARINE...WINDS LESS THAN 15 KT AND SEAS 4 FT OR LESS WILL PREVAIL
THROUGH THE PERIOD. PREVAILING WINDS WILL BE FROM THE E-SE.
&&
.FIRE WEATHER...NO CONCERNS DUE TO HIGH MOISTURE LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 88 74 89 76 / 50 20 40 40
FORT LAUDERDALE 88 78 87 77 / 40 20 40 40
MIAMI 89 78 88 76 / 40 20 40 40
NAPLES 90 73 90 73 / 40 30 60 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
LONG TERM...57/DG
SHORT TERM/AVIATION...04/AT
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
545 AM EDT FRI JUL 4 2008
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS THE MID ATLANTIC THROUGH THE
HOLIDAY WEEKEND. CONDITIONS WILL REMAIN UNSETTLED INTO THE FIRST
PART OF NEXT WEEK. A SECOND FRONTAL BOUNDARY WILL MOVE ACROSS THE
AREA ON WEDNESDAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH
DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR LOOP SHOWS AN UPPER LOW OVER THE HUDSON BAY...WITH A
RIDGE AMPLIFYING NORTHWARD ALONG THE ROCKIES. WEAK SHORTWAVES ARE
ROUNDING THIS RIDGE...AND CROSSING OVER THE PLAINS. MEANWHILE...A
SHORTWAVE EMBEDDED WITHIN THE MEAN FLOW IS MOVING SOUTHEAST OVER THE
UPPER MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A SOUTHERLY
80-135KT JET FROM THE EASTERN GREAT LAKES NORTHEAST INTO EASTERN
CANADA. A 50-70KT NORTHWESTERLY JET WAS CROSSING OVER THE UPPER
MIDWEST. 02Z SURFACE ANALYSIS PLACED A STALLING COLD FRONT FROM THE
NEW ENGLAND COAST...SOUTHWEST THROUGH THE OHIO VALLEY AND INTO THE
PLAINS. A TROUGH WAS NOTED ALONG THE CENTRAL APPALACHIANS. AN
OUTFLOW BOUNDARY WAS DETECTED BY THE WSR-88D NETWORK MOVING
SOUTHEAST TOWARD THE WESTERN BALTIMORE/DC SUBURBS.
PER WSR-88D NETWORK...MCV HAS THE LOOK OF BEING SHEARED NORTHEAST
OVERNIGHT AS IT CROSSED OVER NORTHERN WEST VIRGINIA. CONVECTION
ACROSS WEST VIRGINIA AND SOUTHERN PENNSYLVANIA HAS SENT AN OUTFLOW
SOUTHEAST CROSSING MUCH OF THE FORECAST AREA...HOWEVER THE
BAROCLINIC ZONE STILL RESIDES ACROSS CENTRAL PENNSYLVANIA.
NEXT SHORTWAVE APPROACHES FROM THE SOUTHWEST DURING THE
AFTERNOON...AS THE DISTURBANCE OVER THE UPPER MIDWEST MOVES TOWARD
THE LOWER GREAT LAKES. THIS SHOULD INCREASE EFFECTIVE SHEAR VALUES
TO ABOUT 30 KTS PER THE 21Z SREF. ALSO...00Z NAM80 SHOWS THE
700-500MB TROUGH DEEPENS ACROSS THE OHIO VALLEY THIS
AFTERNOON...WITH VERTICAL MOTION THROUGH THE SAME LAYER
STRENGTHENING ACROSS THE CENTRAL AND EASTERN FORECAST AREA LATE THIS
AFTERNOON AND EVENING. BELIEVE 00Z NAM HAS A BETTER DEPICTION WITH
CONVECTIVE FEEDBACK SEEN ON THE 00Z GFS.
INSTABILITY WILL VARY ACROSS THE FORECAST AREA TODAY. WHERE GREATER
CLOUD COVER AND PRECIPITATION COVERAGE TAKES PLACE...THE NORTHWEST
ZONES...ANTICIPATE LESS OF A CHANCE OF STRONG OR SEVERE CONVECTION.
COMBINATION OF HEATING AND INCREASE IN MOISTURE FROM THE COAST
SHOULD LEAD TO BEST INSTABILITY (500-1000 J/KG MLCAPE) ACROSS THE
SOUTHEAST AND EASTERN FORECAST AREA. THIS IS LIKELY WHERE THE
STRONGEST STORMS WILL DEVELOP...SOME OF WHICH MAY PRODUCE LOCALLY
DAMAGING WINDS OR LARGE HAIL ESPECIALLY DURING THE LATE AFTERNOON
AND EVENING. DANGEROUS CLOUD TO GROUND LIGHTNING AND LOCALLY HEAVY
RAINFALL (PRECIPITABLE WATER VALUES ABOUT 75TH PERCENTILE FOR THIS
DATE) WILL BE THE MORE COMMON THREATS WITH STORMS TODAY. THANKS FOR
THE COLLABORATION SPC!
TEMPERATURES EXPECTED TO NEAR 90F ACROSS THE FAR SOUTHEAST
ZONES...70S IN THE WESTERN ZONES WITH CLOUD COVER AND ELEVATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
CONVECTION EXPECTED TO PROGRESS EASTWARD TOWARD DELMARVA...AND
DEVELOP NORTHWARD IN PENNSYLVANIA AS THE MID LEVEL TROUGH DEVELOPS
OVER THE OHIO VALLEY TONIGHT.
BAROCLINIC ZONE EXPECTED TO SHIFT SOUTH TONIGHT...OWING TO LOWER
PRESSURES ACROSS SOUTHERN VIRGINIA WHICH DEVELOP DURING THE
AFTERNOON DUE TO DIFFERENTIAL HEATING. THIS MAY LEAD TO PATCHY FOG
AFTER THE RAINS...DESPITE CLOUD COVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE MEDIUM RANGE FORECAST WILL BE UNDER THE INFLUENCE OF THE
STALLED SURFACE BOUNDARY OVER THE REGION WITH THE UPPER LOW AND
TROUGH AXIS SWINGING THROUGH. A SERIES OF SHORT WAVE IMPULSES AT
THE SURFACE AND ALOFT WILL RIDE ALONG THE FRONT THROUGH THE
WEEKEND.
THE MAIN CHALLENGE WITH THIS SYSTEM REMAINS WITH THE POTENTIAL OR
LACK OF POTENTIAL FOR SEVERE WEATHER. EXTENSIVE CLOUD COVER IS
EXPECTED SATURDAY AND SUNDAY BEFORE GRADUALLY IMPROVING ON MONDAY AS
THE FRONT DISSIPATES. HOWEVER...TIME BETWEEN IMPULSES COULD ALLOW
FOR SOME BREAKS IN THE CLOUDS. THAT WOULD ENHANCE LOW LEVEL
INSTABILITY TO INCREASE CAPE VALUES. OTHERWISE...STORMS WILL RELAY
ON STEEPENED LAPSE RATES WITH A COLD POOL...INCREASING WIND SHEAR
AHEAD OF APPROACHING MID LEVEL TROUGHS AND WAVES...AND MESOSCALE
BOUNDARIES LINGERING FROM ONGOING OR RECENT STORMS. PRECIPITABLE
WATER VALUES INCREASE TO BETWEEN 1.75 AND 2.0 INCHES. THIS IS NOT
EXCEPTIONALLY HIGH FOR JULY...BUT SEVERAL WAVES COULD LEAD TO SOME
FLOODING PROBLEMS. THIS IS ESPECIALLY TRUE WITH RELATIVELY WEAK
STORM MOTION AND TRAINING STORMS.
WHILE THERE IS DISCREPANCY IN WHEN THE STALLED FRONT WILL FINALLY
EXIT/DISSIPATE...MONDAY LOOKS TO REMAIN ON THE CLOUDY SIDE WITH
CHANCE POPS.
A SURFACE LOW WILL TRACK EAST ACROSS THE GREAT LAKES
TUESDAY...DRAGGING A COLD FRONT EAST TOWARDS THE MID ATLANTIC FOR
WEDNESDAY. HIGH PRESSURE OFF THE SOUTHEAST COAST WILL FEED IN A
WARMER AND MORE HUMID AIRMASS FOR THE EARLY TO MIDDLE WORK WEEK.
THIS WILL ALL COMBINE FOR A CONTINUATION OF THE UNSETTLED PATTERN
THROUGH THE REMAINDER OF THE LONG RANGE FORECAST.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
NEXT DISTURBANCE EXPECTED TO SUPPORT NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS THE MOUNTAINS TODAY...WITH MORE SCATTERED...BUT
STRONGER STORMS DEVELOPING EAST OF THE BLUE RIDGE LATE THIS
AFTERNOON AND EVENING. SOME OF THESE STORMS MAY SUPPORT MVFR
CEILINGS/IFR VISIBILITIES. CONVECTION EXPECTED TO PROGRESS EAST
TOWARD DELMARVA...AND DEVELOP NORTHWARD INTO PENNSYLVANIA TONIGHT.
PATCHY FOG MAY DEVELOP LATER TONIGHT. VARIABLE WINDS DURING TODAY
WILL TEND TO BECOME LIGHT OUT OF THE NORTH TONIGHT AS THE FRONTAL
ZONE SHIFTS SOUTH INTO CENTRAL VIRGINIA.
A STALLED FRONTAL BOUNDARY WILL REMAIN OVER THE REGION THROUGH
THE WEEKEND...BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS
THROUGH MONDAY. SOME STORMS WILL BRING GUSTY WINDS AND HEAVY
DOWNPOURS THAT WILL BRING MVFR TO IFR CONDITIONS.
WHILE THE FRONT WILL DISSIPATE EARLY NEXT WEEK...SOUTHERLY WINDS
WILL BRING A WARM AND HUMID AIRMASS AS WELL AND LINGERING
PRECIPITATION CHANCES TO THE REGION THROUGH THE MID WEEK.
&&
.MARINE...
ALLOWED SMALL CRAFT ACROSS MID BAY TO EXPIRE AS WIND GUSTS ARE
DIMINISHING SLIGHTLY AS FORECAST.
GENERALLY LIGHT WINDS TODAY...BECOMING NORTH/NORTHEAST TONIGHT AS
THE COLD FRONT SHIFTS SOUTHWARD. SCATTERED THUNDERSTORMS DEVELOP
THIS AFTERNOON...BECOMING MORE NUMEROUS BY EVENING. THESE
THUNDERSTORMS WILL CONTAIN DANGEROUS CLOUD TO GROUND LIGHTNING AND
HEAVY DOWNPOURS. THE STRONGEST ACTIVITY MAY CONTAIN LOCALLY DAMAGING
WINDS AND LARGE HAIL...AND MAY WARRANT SPECIAL MARINE WARNINGS. THE
MOST PROBABLE TIME FOR THESE THUNDERSTORMS IS BETWEEN 6 PM AND 10 PM.
A STALLED FRONTAL BOUNDARY WILL REMAIN OVER THE MID ATLANTIC
THROUGH THE WEEKEND...BRINGING PERIODS OF SHOWERS AND
THUNDERSTORMS THROUGH MONDAY. THE STRONGER STORMS WILL BE CAPABLE
OF PRODUCING WIND GUSTS IN EXCESS OF 30 KNOTS.
WHILE THE FRONT WILL DISSIPATE EARLY NEXT WEEK...SOUTHERLY WINDS
WILL BRING A WARM AND HUMID AIRMASS AS WELL AND LINGERING
PRECIPITATION CHANCES TO THE REGION THROUGH THE MID WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SAR
NEAR TERM...ROGOWSKI
SHORT TERM...ROGOWSKI
LONG TERM...SAR
AVIATION...ROGOWSKI/SAR
MARINE...ROGOWSKI/SAR
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
258 AM EDT FRI JUL 4 2008
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS THE MID ATLANTIC THROUGH THE
HOLIDAY WEEKEND. CONDITIONS WILL REMAIN UNSETTLED INTO THE FIRST
PART OF NEXT WEEK. A SECOND FRONTAL BOUNDARY WILL MOVE ACROSS THE
AREA ON WEDNESDAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH
DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR LOOP SHOWS AN UPPER LOW OVER THE HUDSON BAY...WITH A
RIDGE AMPLIFYING NORTHWARD ALONG THE ROCKIES. WEAK SHORTWAVES ARE
ROUNDING THIS RIDGE...AND CROSSING OVER THE PLAINS. MEANWHILE...A
SHORTWAVE EMBEDDED WITHIN THE MEAN FLOW IS MOVING SOUTHEAST OVER THE
UPPER MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A SOUTHERLY
80-135KT JET FROM THE EASTERN GREAT LAKES NORTHEAST INTO EASTERN
CANADA. A 50-70KT NORTHWESTERLY JET WAS CROSSING OVER THE UPPER
MIDWEST. 02Z SURFACE ANALYSIS PLACED A STALLING COLD FRONT FROM THE
NEW ENGLAND COAST...SOUTHWEST THROUGH THE OHIO VALLEY AND INTO THE
PLAINS. A TROUGH WAS NOTED ALONG THE CENTRAL APPALACHIANS. AN
OUTFLOW BOUNDARY WAS DETECTED BY THE WSR-88D NETWORK MOVING
SOUTHEAST TOWARD THE WESTERN BALTIMORE/DC SUBURBS.
PER WSR-88D NETWORK...MCV HAS THE LOOK OF BEING SHEARED NORTHEAST
OVERNIGHT AS IT CROSSED OVER NORTHERN WEST VIRGINIA. CONVECTION
ACROSS WEST VIRGINIA AND SOUTHERN PENNSYLVANIA HAS SENT AN OUTFLOW
SOUTHEAST CROSSING MUCH OF THE FORECAST AREA...HOWEVER THE
BAROCLINIC ZONE STILL RESIDES ACROSS CENTRAL PENNSYLVANIA.
NEXT SHORTWAVE APPROACHES FROM THE SOUTHWEST DURING THE
AFTERNOON...AS THE DISTURBANCE OVER THE UPPER MIDWEST MOVES TOWARD
THE LOWER GREAT LAKES. THIS SHOULD INCREASE EFFECTIVE SHEAR VALUES
TO ABOUT 30 KTS PER THE 21Z SREF. ALSO...00Z NAM80 SHOWS THE
700-500MB TROUGH DEEPENS ACROSS THE OHIO VALLEY THIS
AFTERNOON...WITH VERTICAL MOTION THROUGH THE SAME LAYER
STRENGTHENING ACROSS THE CENTRAL AND EASTERN FORECAST AREA LATE THIS
AFTERNOON AND EVENING. BELIEVE 00Z NAM HAS A BETTER DEPICTION WITH
CONVECTIVE FEEDBACK SEEN ON THE 00Z GFS.
INSTABILITY WILL VARY ACROSS THE FORECAST AREA TODAY. WHERE GREATER
CLOUD COVER AND PRECIPITATION COVERAGE TAKES PLACE...THE NORTHWEST
ZONES...ANTICIPATE LESS OF A CHANCE OF STRONG OR SEVERE CONVECTION.
COMBINATION OF HEATING AND INCREASE IN MOISTURE FROM THE COAST
SHOULD LEAD TO BEST INSTABILITY (500-1000 J/KG MLCAPE) ACROSS THE
SOUTHEAST AND EASTERN FORECAST AREA. THIS IS LIKELY WHERE THE
STRONGEST STORMS WILL DEVELOP...SOME OF WHICH MAY PRODUCE LOCALLY
DAMAGING WINDS OR LARGE HAIL ESPECIALLY DURING THE LATE AFTERNOON
AND EVENING. DANGEROUS CLOUD TO GROUND LIGHTNING AND LOCALLY HEAVY
RAINFALL (PRECIPITABLE WATER VALUES ABOUT 75TH PERCENTILE FOR THIS
DATE) WILL BE THE MORE COMMON THREATS WITH STORMS TODAY. THANKS FOR
THE COLLABORATION SPC!
TEMPERATURES EXPECTED TO NEAR 90F ACROSS THE FAR SOUTHEAST
ZONES...70S IN THE WESTERN ZONES WITH CLOUD COVER AND ELEVATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
CONVECTION EXPECTED TO PROGRESS EASTWARD TOWARD DELMARVA...AND
DEVELOP NORTHWARD IN PENNSYLVANIA AS THE MID LEVEL TROUGH DEVELOPS
OVER THE OHIO VALLEY TONIGHT.
BAROCLINIC ZONE EXPECTED TO SHIFT SOUTH TONIGHT...OWING TO LOWER
PRESSURES ACROSS SOUTHERN VIRGINIA WHICH DEVELOP DURING THE
AFTERNOON DUE TO DIFFERENTIAL HEATING. THIS MAY LEAD TO PATCHY FOG
AFTER THE RAINS...DESPITE CLOUD COVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
THE MEDIUM RANGE FORECAST WILL BE UNDER THE INFLUENCE OF THE
STALLED SURFACE BOUNDARY OVER THE REGION WITH THE UPPER LOW AND
TROUGH AXIS SWINGING THROUGH. A SERIES OF SHORT WAVE IMPULSES AT
THE SURFACE AND ALOFT WILL RIDE ALONG THE FRONT THROUGH THE
WEEKEND.
THE MAIN CHALLENGE WITH THIS SYSTEM REMAINS WITH THE POTENTIAL OR
LACK OF POTENTIAL FOR SEVERE WEATHER. EXTENSIVE CLOUD COVER IS
EXPECTED SATURDAY AND SUNDAY BEFORE GRADUALLY IMPROVING ON MONDAY AS
THE FRONT DISSIPATES. HOWEVER...TIME BETWEEN IMPULSES COULD ALLOW
FOR SOME BREAKS IN THE CLOUDS. THAT WOULD ENHANCE LOW LEVEL
INSTABILITY TO INCREASE CAPE VALUES. OTHERWISE...STORMS WILL RELAY
ON STEEPENED LAPSE RATES WITH A COLD POOL...INCREASING WIND SHEAR
AHEAD OF APPROACHING MID LEVEL TROUGHS AND WAVES...AND MESOSCALE
BOUNDARIES LINGERING FROM ONGOING OR RECENT STORMS. PRECIPITABLE
WATER VALUES INCREASE TO BETWEEN 1.75 AND 2.0 INCHES. THIS IS NOT
EXCEPTIONALLY HIGH FOR JULY...BUT SEVERAL WAVES COULD LEAD TO SOME
FLOODING PROBLEMS. THIS IS ESPECIALLY TRUE WITH RELATIVELY WEAK
STORM MOTION AND TRAINING STORMS.
WHILE THERE IS DISCREPANCY IN WHEN THE STALLED FRONT WILL FINALLY
EXIT/DISSIPATE...MONDAY LOOKS TO REMAIN ON THE CLOUDY SIDE WITH
CHANCE POPS.
A SURFACE LOW WILL TRACK EAST ACROSS THE GREAT LAKES
TUESDAY...DRAGGING A COLD FRONT EAST TOWARDS THE MID ATLANTIC FOR
WEDNESDAY. HIGH PRESSURE OFF THE SOUTHEAST COAST WILL FEED IN A
WARMER AND MORE HUMID AIRMASS FOR THE EARLY TO MIDDLE WORK WEEK.
THIS WILL ALL COMBINE FOR A CONTINUATION OF THE UNSETTLED PATTERN
THROUGH THE REMAINDER OF THE LONG RANGE FORECAST.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
NEXT DISTURBANCE EXPECTED TO SUPPORT NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS THE MOUNTAINS TODAY...WITH MORE SCATTERED...BUT
STRONGER STORMS DEVELOPING EAST OF THE BLUE RIDGE LATE THIS
AFTERNOON AND EVENING. SOME OF THESE STORMS MAY SUPPORT MVFR
CEILINGS/IFR VISIBILITIES. CONVECTION EXPECTED TO PROGRESS EAST
TOWARD DELMARVA...AND DEVELOP NORTHWARD INTO PENNSYLVANIA TONIGHT.
PATCHY FOG MAY DEVELOP LATER TONIGHT. VARIABLE WINDS DURING TODAY
WILL TEND TO BECOME LIGHT OUT OF THE NORTH TONIGHT AS THE FRONTAL
ZONE SHIFTS SOUTH INTO CENTRAL VIRGINIA.
A STALLED FRONTAL BOUNDARY WILL REMAIN OVER THE REGION THROUGH
THE WEEKEND...BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS
THROUGH MONDAY. SOME STORMS WILL BRING GUSTY WINDS AND HEAVY
DOWNPOURS THAT WILL BRING MVFR TO IFR CONDITIONS.
WHILE THE FRONT WILL DISSIPATE EARLY NEXT WEEK...SOUTHERLY WINDS
WILL BRING A WARM AND HUMID AIRMASS AS WELL AND LINGERING
PRECIPITATION CHANCES TO THE REGION THROUGH THE MID WEEK.
&&
.MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT SOUTH OF NORTH BEACH ON
THE MARYLAND CHESAPEAKE BAY EARLY THIS MORNING. SOUTHERLY WINDS
ARE CHANNELING UP THE BAY...FURTHER NORTH...AN OUTFLOW BOUNDARY
HAS STABILIZED WINDS.
GENERALLY LIGHT WINDS TODAY...BECOMING NORTH/NORTHEAST TONIGHT AS
THE COLD FRONT SHIFTS SOUTHWARD. SCATTERED THUNDERSTORMS DEVELOP
THIS AFTERNOON...BECOMING MORE NUMEROUS BY EVENING. THESE
THUNDERSTORMS WILL CONTAIN DANGEROUS CLOUD TO GROUND LIGHTNING AND
HEAVY DOWNPOURS. THE STRONGEST ACTIVITY MAY CONTAIN LOCALLY DAMAGING
WINDS AND LARGE HAIL...AND MAY WARRANT SPECIAL MARINE WARNINGS. THE
MOST PROBABLE TIME FOR THESE THUNDERSTORMS IS BETWEEN 6 PM AND 10 PM.
A STALLED FRONTAL BOUNDARY WILL REMAIN OVER THE MID ATLANTIC
THROUGH THE WEEKEND...BRINGING PERIODS OF SHOWERS AND
THUNDERSTORMS THROUGH MONDAY. THE STRONGER STORMS WILL BE CAPABLE
OF PRODUCING WIND GUSTS IN EXCESS OF 30 KNOTS.
WHILE THE FRONT WILL DISSIPATE EARLY NEXT WEEK...SOUTHERLY WINDS
WILL BRING A WARM AND HUMID AIRMASS AS WELL AND LINGERING
PRECIPITATION CHANCES TO THE REGION THROUGH THE MID WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
ANZ533-534.
&&
$$
SYNOPSIS...SAR
NEAR TERM...ROGOWSKI
SHORT TERM...ROGOWSKI
LONG TERM...SAR
AVIATION...ROGOWSKI/SAR
MARINE...ROGOWSKI/SAR
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
230 PM EDT SAT JUL 5 2008
LATEST UPDATE...ALL SECTIONS...
.SYNOPSIS...(230 PM EDT SAT JUL 5 2008)
HIGH PRESSURE OVERHEAD WILL MOVE SLOWLY EAST THROUGH SUNDAY. WARM
AND DRY WEATHER WILL CONTINUE INTO SUNDAY. A LOW PRESSURE SYSTEM
WILL MOVE
INTO THE REGION ON MONDAY AND PERSIST THROUGH TUESDAY. WARM HUMID
AIR AND NUMEROUS SHOWERS AND THUNDERSTORMS WILL LIKELY OCCUR MONDAY
NIGHT INTO TUESDAY. CANADIAN HIGH PRESSURE WILL BRING COOLER AND
DRIER AIR FOR WED INTO THU.
&&
.SHORT TERM...(230 PM EDT SAT JUL 5 2008)
(TODAY THROUGH SUNDAY)
FORECAST CONCERNS ARE MINIMAL TODAY BUT DEAL WITH CONVECTIVE
POTENTIAL LATE MONDAY.
EXPECT TONIGHT WILL BE SIMILAR TO LAST NIGHT EXCEPT ABOUT 3 TO 5
DEGREES WARMER. GOOD RADIATIONAL COOLING...LIGHT WINDS...AND WET
GROUND SHOULD PRODUCE PATCHY FOG AGAIN. SUNDAY...WARMING TREND
CONTINUES WITH HIGH REACHING LOWER 80S. DEWPOINTS START AN UPWARD
TREND WITH S FLOW ON BACK SIDE OF EXITING HIGH PRESSURE.
KEPT CHC POPS FOR EARLY MONDAY MORNING - EXPECTATION IS FOR
WEAKENING CONVECTION MOVING ACROSS LAKE ASSOCIATED WITH WARM FRONT.
TREND HAS BEEN SLOWER SO POPS A BIT LOWER THAN PREVIOUS PACKAGE.
&&
.LONG TERM...(336 AM EDT SAT JUL 5 2008)
(MONDAY THROUGH FRIDAY)
FEW SHOWERS AND TSTORMS ARE ANTICIPATED MONDAY AND IT WILL
CONTINUE TO BECOME MUCH MORE HUMID AS DEW POINTS CLIMB THROUGH THE
60S TO NEAR 70 DEGREES BY MONDAY EVENING. CONVECTION WILL BECOME
MORE LIKELY MONDAY NIGHT AS ELEVATED INSTABILITY CONTINUES TO
INCREASE ALONG WITH THE CONTINUED INFLUX OF RICHER LOW LEVEL
MOISTURE IN CONTINUED SW FLOW. WE ARE ALSO CONCERNED THAT A 30-40 KT
LLJ WILL TRIGGER MCS DEVELOPMENT OFF TO OUR WEST WHICH COULD ROLL
INTO OUR CWFA LATE MONDAY NIGHT.
OUR BEST CHC FOR CONVECTION WILL COME TUESDAY. FCST SOUNDINGS BECOME
NEARLY SATURATED BY LATE TUESDAY AND PWAT VALUES WILL RAMP UP
SIGNIFICANTLY TO 2-2.5 INCHES OUT AHEAD OF THE APPROACHING AND
INTENSIFYING LOW PRESSURE SYSTEM. THIS SYSTEM WILL CERTAINLY NEED TO
BE MONITORED CLOSELY FOR SVR WX POTENTIAL TUESDAY. POTENTIAL FOR
HEAVY RAIN IS ALSO QUITE HIGH... WHICH WILL LIKELY RESULT IN SOME
HYDRO ISSUES.
HIGH PRESSURE WILL BUILD IN BEHIND THAT SYSTEM FOR MID TO LATE
WEEK... RESULTING IN FAIR AND COOL WX. BASED ON LATEST MEDIUM RANGE
GUIDANCE AND TRENDS... WE LOWERED THE FCST MAX/MIN TEMPS SOMEWHAT
FOR WED-THUR. DRY WX AND A MODERATING TREND OF TEMPS IS ANTICIPATED
LATE IN THE WEEK INTO NEXT WEEKEND AS THE H5 RIDGE AXIS BUILDS IN.
IN FACT TEMPS SHOULD AVG 5 TO 10 DEGREES ABOVE NORMAL BY SATURDAY.
&&
.MARINE...(230 PM EDT SAT JUL 5 2008)
NO CONCERNS THROUGH SUNDAY. WAVES INCREASE WITH S FLOW SUNDAY NIGHT
INTO MONDAY. THREAT OF SHOWERS AND THUNDERSTORMS BEGINNING MONDAY
THROUGH TUESDAY EVENING. AREAS OF FOG AS WELL MONDAY NIGHT.
&&
.AVIATION...(230 PM EDT SAT JUL 5 2008)
VFR CONDITIONS EXCEPT FOR PATCHY FOG BETWEEN 09Z AND 12Z SUNDAY
MORNING. SOME LIGHT CHOP FOR SMALL AIRCRAFT ALONG LAKE BREEZE FRONT
THIS AFTERNOON. THE FRONT WILL BE ROUGHLY 10 INLAND AND PARALLEL THE
COAST. OUTLOOK - VFR ON SUNDAY WITH INCREASING S WINDS.
&&
.HYDROLOGY...(230 PM EDT SAT JUL 5 2008)
RIVERS SLOWLY RECEEDING FROM LAST WEEKS EVENT. NEW CONCERN FOR HEAVY
RAINFALL MONDAY INTO TUESDAY WITH NEXT FRONTAL SYSTEMS. PWATS OF
ABOVE 2 INCHES FOR 24-36 HOUR PERIOD AND A LOW LEVEL JET OF 30 TO 40
KTS WILL INTERSECT A FRONTAL BOUNDARY RESULTING IN A POTENTIAL
RAINFALL OF LOCALLY SEVERAL INCHES. STILL PLENTY OF SPREAD IN NWP
GUIDANCE AS TO WHERE THE FRONTAL BOUNDARY WILL BE MONDAY NIGHT INTO
TUESDAY MORNING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: COBB
SHORT TERM: COBB
LONG TERM: LAURENS
MARINE: COBB
AVIATION: COBB
HYDROLOGY: COBB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1042 AM EDT FRI JUL 4 2008
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL CONTINUE TO EXTEND
WESTWARD INTO THE REGION THROUGH THE FOURTH OF JULY. MOISTURE WILL
CONTINUE TO INCREASE OVER THE AREA HEADING INTO THE WEEKEND...
LEADING TO AN INCREASING CHANCE OF SHOWERS AND STORMS.
&&
.NEAR TERM /THROUGH EARLY TONIGHT/...
AS OF 1045 AM FRIDAY...
12Z SOUNDING FROM GSO SHOWS THAT PRECIPITABLE WATERS CONTINUE TO
STEADILY RISE THIS MORNING WITH 1.14 INCHES PRESENT...ABOUT 90
PERCENT OF NORMAL. LAPSE RATES ARE ALSO VERY STEEP THROUGH 700
MB...BUT THEN WARM IN THE MID LEVELS WITH A BIT OF A CAP STILL
PRESENT. THE MHX SOUNDING FROM THIS MORNING SHOWS A MUCH STRONGER
CAP ABOVE 700 MB...WHILE THERE IS ESSENTIALLY NO CAP PRESENT AT RNK.
CLOUD COVER HAS BEEN MINIMAL THIS MORNING WITH JUST SOME MID AND
HIGH LEVEL CLOUDS PASSING BY. WITH ALL OF THE CONVECTION ASSOCIATED
WITH THE FRONT WELL TO OUR NORTH AND A MEAN SW FLOW... EXPECT MOST
DEBRIS CLOUDS TO REMAIN NORTH OF US THROUGH THIS AFTERNOON. WHILE WE
WILL SEE DIURNAL CUMULUS THIS AFTERNOON...HAVE A ADDED A DEGREE OR
TWO TO MAX TEMPS TO ACCOUNT FOR LESS CONVECTIVE DEBRIS AND LOW LEVEL
THICKNESSES REACHING ABOUT 10-15 M HIGHER THAN YESTERDAY. THIS
SHOULD GIVE LOW 90S NW PIEDMONT TO MID 90S ELSEWHERE THIS AFTERNOON.
ALTHOUGH DEWPOINTS ARE CURRENTLY IN THE UPPER 60S TO NEAR 70... THE
PRESENCE OF A DEEP MIXED LAYER THROUGH 700 MB WITH DRY AIR
PRESENT...SHOULD HELP DEWPOINTS TO MIX OUT TO THE UPPER 50S NW TO
LOW 60S IN THE COASTAL PLAIN. SO...ALTHOUGH IT WILL BE HOT...LOWER
HUMIDITY VALUES WILL KEEP IT FROM FEELING OPPRESSIVE.
REGARDING CONVECTIVE POTENTIAL... LOWERING DEWPOINTS THIS AFTERNOON
ALONG WITH THE PRESENCE OF A MID LEVEL CAP EFFECTIVELY LIMIT THE
AMOUNT OF MIXED LAYER CAPE TODAY... GENERALLY WELL UNDER A 1000
J/KG. THUS...EXPECT MOST OF THE DAY TO BE CONVECTION FREE. AGREE
WITH THE PREVIOUS FORECAST THAT PRECIP CHANCES WILL BEGIN TO
INCREASE IN THE NW EARLY THIS EVENING AS MASS LOW LEVEL CONVERGENCE
INCREASES AND THE MID LEVEL CAP IS REMOVED. ALSO...OUTFLOW
BOUNDARIES WILL LIKELY PLAY A ROLE THIS EVENING...AS THEY EMANATE
FROM CONVECTION OVER THE MOUNTAINS AND FOOTHILLS... WHICH WILL BE IN
A BETTER REGIME FOR CONVECTION THIS AFTERNOON. A WEAK 500 MB WAVE
OVER NASHVILLE (-12C THERE COMPARED TO TEMPS 2-3C WARMER ELSEWHERE)
WILL ALSO MOVE EAST TODAY AND HELP CONVECTION INITIATE IN THE
MOUNTAINS. WILL MAINTAIN THE PREVIOUS FORECAST OF CHANCE POPS
ENTERING THE NORTHWEST PIEDMONT THIS EVENING. IF WE CAN REALIZE
CONVECTION OVER THE NW THIS EVENING...THEN A FEW STORMS COULD BE
STRONG WITH GUSTY WINDS...AS THE STEEP LAPSE RATES EVIDENT ON THE
GSO SOUNDING WILL ALLOW FOR EXCELLENT EVAPORATIVE COOLING. THIS IS
HANDLED WELL IN THE CURRENT HAZARDOUS WEATHER OUTLOOK.
HAVE A HAPPY AND SAFE FOURTH OF JULY!
&&
.SHORT TERM /LATE TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 255 AM FRIDAY...
FOR LATE TONIGHT THROUGH SATURDAY: THE UPPER JET CORE NOW STRETCHING
FROM THE DAKOTAS DOWN TO NRN MO WILL ROUND THE TROUGH BASE TONIGHT
INTO SATURDAY MORNING... PLACING NC IN ITS RIGHT ENTRANCE REGION.
MEANWHILE THE DEEP LAYER SHEAR BEGINS TO INCREASE... RISING TO 20-25
KTS FROM 06Z-12Z TONIGHT... SO A FEW STORMS EVEN LATER TONIGHT COULD
BECOME STRONG. GIVEN MODEL CONSENSUS THAT PRECIPITABLE WATER WILL
APPROACH 1.9-2.0 INCHES BY SATURDAY MORNING AS WE TAP INTO THE
HIGHER GULF-SOURCE MOISTURE... THE PRESENCE OF AN 850 MB THETA-E
RIDGE FROM AL/GA THROUGH NC... AND WITH THE INCOMING FORCING FOR
ASCENT DUE TO THE INCREASING UPPER LEVEL DIVERGENCE... RISING POPS
INTO THE HIGH CHANCE/LOW LIKELY RANGE SATURDAY STILL LOOKS GOOD AND
REASONABLE... ALTHOUGH I DON`T FORESEE A NONSTOP SOAKING LASTING ALL
DAY... BUT RATHER PERIODS OF SHOWERS AND SCATTERED STORMS. FORECAST
SOUNDINGS INDICATE LAYERS OF DRY AIR UPSTAIRS DURING THE DAY... SUCH
THAT WE SHOULD SEE SOME BREAKS IN THE CLOUDS ESPECIALLY ACROSS THE
SOUTHERN AND EASTERN CWA. LOW LEVEL THICKNESSES WITH A LITTLE BIT OF
SUNSHINE SUPPORT HIGHS OF 87-92.
FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT: IN SHORT... EXPECT
ON-AND-OFF SCATTERED TO NUMEROUS SHOWERS AND STORMS THROUGH THE
LATTER HALF OF THE WEEKEND... WITH PRECIPITABLE WATER REMAINING NEAR
150% OF NORMAL... BOUNDARY LAYER FLOW REMAINING CONFLUENT OUT OF THE
S AND SW KEEPING LOW LEVEL MOISTURE ELEVATED... AND THE MID LEVEL
TROUGH AXIS HOLDING TO OUR WEST. THE LIFTED CONDENSATION LEVEL
ACROSS THE AREA DROPS EARLY SATURDAY NIGHT AND REMAINS IN THE
900-970 MB RANGE THROUGH SUNDAY NIGHT. THIS YIELDS A DEEPENING
LCL-TO-FREEZING-LEVEL LAYER TO 3.5-3.8 KM WHICH FAVORS WARM RAIN
PROCESSES... AND SOME BANDS OF HEAVIER SHOWERS ARE POSSIBLE.
FORECAST SOUNDINGS SHOW MODERATE INSTABILITY PERSISTING... ALTHOUGH
THE DEEP LAYER SHEAR WILL BE MARGINAL AT AROUND 15-20 KTS... AND A
TIGHT LOW LEVEL JET APPEARS TO BE LACKING... SO THE POTENTIAL FOR
STRONG STORMS STILL LOOKS LIMITED BUT THIS WILL NEED TO BE WATCHED.
FURTHER COMPLICATING MATTERS STARTING SUNDAY IS THE DIVERGENT
SOLUTIONS OF THE NAM AND GFS... WITH THE FORMER CLOSING OFF A MID
LEVEL LOW NEAR MEMPHIS BY LATE SUNDAY WHILE THE LATTER HAS THE WEAK
TROUGH SLOWLY LIFTING OUT TO OUR NW. WHILE THE GFS IS INDEED
TRENDING SLOWLY WITH THE EJECTION OF THIS TROUGH... WHICH IS
REASONABLE CONSIDERING THE NORTHWARD RETREAT OF THE WESTERLIES...
THE NAM LOOKS TOO OVERDONE TOO FAR SOUTH. EITHER WAY... NC REMAINS
ON THE WET SIDE OF THIS TROUGH. HIGHS SUNDAY SHOULD BE JUST UNDER
CLIMATOLOGY WITH ABUNDANT CLOUD COVER. LOWS A CATEGORY ABOVE NORMAL
BOTH NIGHTS. -GIH
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
FOR MONDAY: IF THE GFS/ECMWF SOLUTION OF THE SLOW-MOVING YET
PROGRESSIVE TROUGH AXIS SHIFTING THROUGH THE CENTRAL APPALACHIANS
AND NW NC INTO THE NORTHEAST STATES LATE SUNDAY NIGHT THROUGH MONDAY
ENDS UP CORRECT... WE`RE STILL LIKELY TO SEE SCATTERED TO NUMEROUS
SHOWERS AND STORMS THROUGH MONDAY MORNING. THE GFS SHOWS CONTINUED
MODERATE INSTABILITY AND NORMALIZED CAPE (CAPE FROM LCL TO THE
EQUILIBRIUM LEVEL) EXCEEDS 0.2... FAVORING STRONG UPDRAFTS. WITH
DEEP LAYER SHEAR NEARING 30 KTS AS THE TROUGH AXIS SWEEPS BY TO OUR
NW AND WITH THE MID LEVELS DRYING OUT SOMEWHAT IN THE AFTERNOON...
WE COULD SEE A RISK OF A FEW STRONG STORMS IF THE EXPECTED MORNING
PRECIP AND CLOUDS DON`T HINDER AFTERNOON DESTABILIZATION. HIGHS
SHOULD BE NEAR NORMAL... IN THE UPPER 80S TO NEAR 90.
FOR THE REMAINDER OF THE PERIOD: THE BERMUDA RIDGE ATTEMPTS TO
RETROGRADE BACK TOWARD THE SOUTHEAST COAST AND FL THROUGH MID
WEEK... WHILE SHORTWAVE ENERGY MOVING ACROSS THE US/CANADA BORDER
ALLOWS THE WESTERLIES TO DIP A BIT SOUTHWARD INTO THE NRN GREAT
LAKES/ST LAWRENCE VALLEY/NORTHEAST. VERY LITTLE CHANGES AT THE
SURFACE... WITH THE ATLANTIC-CENTERED SURFACE HIGH HOLDING IN PLACE
AND EXTENDING WSW INTO THE SOUTHEAST COASTAL SECTIONS... WITH A
PERSISTENT PIEDMONT TROUGH OVER CENTRAL/WRN NC AND PRECIPITABLE
WATER REMAINING IN THE 120-140% OF NORMAL RANGE. INASMUCH AS I WOULD
LIKE TO BE ABLE TO DISCERN ONE DAY AS BEING BETTER THAN ANOTHER FOR
SCATTERED MAINLY AFTERNOON/EVENING SHOWERS AND STORMS... AT THIS
RANGE AND WITH MODEL VARIATION IN THE DETAILS... IT REMAINS NEARLY
IMPOSSIBLE. WILL CONTINUE WITH CHANCE POPS... MAINLY AFTERNOON AND
EVENING... TUESDAY THROUGH THURSDAY. GFS/ECMWF THICKNESSES REMAIN
NEAR NORMAL AND TEMPERATURES SHOULD RUN CLOSE TO NORMAL THROUGH THE
PERIOD AS WELL. -GIH
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 705 AM FRIDAY...
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
HOWEVER... ISOLATED TO WIDELY SCATTERED SHOWERS WILL BE POSSIBLE
LATE THIS AFTERNOON AND EVENING AT KINT AND KGSO -- AND PERHAPS AS
FAR EAST AS KRDU -- AS A LEE SIDE SURFACE TROUGH AND GRADUALLY
INCREASING LOW LEVEL MOISTURE MAY PROVE SUFFICIENT TO OVERCOME THE
MID LEVEL CAPPING INVERSION THAT HAS SUPPRESSED DEEP CONVECTION THE
PAST COUPLE OF AFTERNOONS.
OTHERWISE... SCATTERED CUMULUS WILL DEVELOP BY MIDDAY... DEEPEN...
AND EXPAND IN COVERAGE... CONCURRENT WITH AN INCREASE IN MID AND
HIGH LEVEL MOISTURE FROM THE WEST THIS AFTERNOON. THE FLOW AROUND AN
OFFSHORE SURFACE HIGH WILL PROMOTE A CONTINUATION OF SOUTHWESTERLY
SURFACE WINDS BETWEEN 8 AND 12 KNOTS... WITH OCCASIONAL GUSTS TO
BETWEEN 14 AND 18 KTS TODAY... THEN BECOMING LIGHT SOUTHERLY
TONIGHT.
LASTLY... OBSERVED WIND PROFILER DATA INDICATE THE 30 KT LOW LEVEL
JET THAT DEVELOPED OVER CENTRAL NC LAST NIGHT HAS WEAKENED. THE
POTENTIAL EXISTS FOR NOCTURNAL LOW LEVEL JET DEVELOPMENT BETWEEN
1500 AND 2000 FT AGAIN TONIGHT... WITH WINDS WITHIN THE LAYER
ACCELERATING TO BETWEEN 30 AND 40 KNOTS (STRONGEST FROM KRDU
EASTWARD) BETWEEN MIDNIGHT AND 6 AM. WHILE THIS MAY PROMOTE
CONDITIONS JUST SHY OF LLWS CRITERIA... THE ASSOCIATED SHEAR LAYER
MAY PROVIDE FOR A LITTLE TURBULENCE... ESPECIALLY FOR SMALLER
AIRCRAFT.
LOOKING AHEAD... OCCASIONAL MVFR CONDITIONS IN SHOWERS/THUNDERSTORMS
AND MVFR/IFR MORNING STRATUS AND/OR FOG ARE EXPECTED SATURDAY
THROUGH MONDAY... AS AN UPPER LEVEL TROUGH AMPLIFIES OVER THE OHIO
AND TENNESSEE VALLEYS. -MWS
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...JFB
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
721 AM EDT FRI JUL 4 2008
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE ATLANTIC WILL CONTINUE TO EXTEND
WESTWARD INTO THE REGION THROUGH THE FOURTH OF JULY. MOISTURE WILL
CONTINUE TO INCREASE OVER THE AREA HEADING INTO THE WEEKEND...
LEADING TO AN INCREASING CHANCE OF SHOWERS AND STORMS.
&&
.NEAR TERM /TODAY THROUGH EARLY TONIGHT/...
AS OF 140 AM FRIDAY...
THE AIR MASS OVER CENTRAL NC HAS BECOME NOTICEABLY SOUPIER IN THE
LAST 12-24 HOURS... WITH SURFACE DEW POINTS RUNNING SOME 5-10
DEGREES HIGHER THAN AT THIS TIME YESTERDAY... AND NOAA GPS
PRECIPITABLE WATER NOW SITTING NEAR THE SEASONAL NORMAL AROUND 1.25
INCH AND STEADILY CLIMBING. THE LATEST SURFACE ANALYSIS SHOWS THE
COLD FRONT EXTENDING FROM SOUTHEAST NY THROUGH CENTRAL PA AND THE
OHIO VALLEY TO SRN MO. THE MID LEVEL STEERING FLOW SHOULD BE FAIRLY
STATIC TODAY... WITH ONE SHORTWAVE HEADING NE OUT OF NEW ENGLAND AND
MORE SHORTWAVES DROPPING THROUGH MN/IA INTO THE TROUGH... THUS THE
SURFACE FRONT SHOULD ACCORDINGLY MOVE LITTLE THROUGH TONIGHT...
HOLDING TO OUR NORTH WITH A PREFRONTAL TROUGH STRETCHING THROUGH THE
PIEDMONT. NAM UPPER LEVEL TRAJECTORIES INDICATE THAT THE MID AND
HIGH CLOUDINESS... LEFTOVER FROM EARLIER CONVECTION JUST AHEAD OF
THE FRONT... WILL ADVECT INTO NC THROUGH THE DAY... ALTHOUGH IT IS
INITIALLY ENCOUNTERING RESIDENT SINKING AIR IN THE 500-300 MB LAYER
OVER NC. AS THE UPPER LEVEL SHEAR AXIS SHIFTS EAST OFF THE COAST...
THIS SUBSIDENCE SHOULD WANE AND WE SHOULD SEE A STEADY INCREASE IN
MID AND HIGH CLOUDS PARTICULARLY OVER THE NORTHWEST CWA THIS
AFTERNOON... WITH AN EVENTUAL TREND TO MOSTLY CLOUDY/CLOUDY
OVERNIGHT.
REGARDING THE CONVECTIVE THREAT... FORECAST SOUNDINGS THROUGH THIS
AFTERNOON SHOW MINIMAL MLCAPE... JUST A COUPLE HUNDRED J/KG... DUE
TO RELATIVELY WARM AIR AND WEAK LAPSE RATES ALOFT... AND SREF
PROBABILITIES OF CAPE GREATER THAN 1000 J/KG IS VERY SMALL. AS WE
GET TOWARD EVENING THOUGH... LAPSE RATES ALOFT STEEPEN A BIT WHILE
WE START TO LOSE THE ALREADY-WEAK MID LEVEL CAP... AND GFS SURFACE
CAPE JUMPS UP NEAR 1000/JG. THIS IS ALL CONCURRENT WITH THE STEADY
INCREASE AND DEEPENING OF MOISTURE THROUGH THE COLUMN. BOUNDARY
LAYER FLOW IS PROJECTED TO BECOME INCREASINGLY CONFLUENT FAVORING
IMPROVING MASS CONVERGENCE... AND WE MAY ALSO HAVE TO CONTEND WITH
OUTFLOW BOUNDARIES DROPPING SOUTHWARD FROM ORGANIZED CONVECTION TO
OUR NORTH AND NW... WHICH MAY PROVIDE AN ADDITIONAL FOCUS FOR
SCATTERED STORMS. WILL GO WITH A CHANCE OF THUNDERSTORMS AFTER 6 PM
ACROSS THE NORTHWEST AND NORTHERN CWA WITH LESSER SLIGHT CHANCES
LATE TONIGHT ACROSS THE SOUTHEAST.
FINALLY... REGARDING TEMPS... THE INCREASING CLOUDS SHOULD BALANCE
OUT WITH THE WARMING THICKNESSES PRODUCING HIGHS FROM 89-95... JUST
UNDER MOS GUIDANCE HIGHS WHICH APPEAR TOO WARM CONSIDERING THE
EXPECTED LOW LEVEL THICKNESSES. WITH A LIGHT SOUTHWEST BREEZE
OVERNIGHT AND RISING DEW POINTS... EXPECT MILD LOWS OF 69-74. -GIH
&&
.SHORT TERM /LATE TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 255 AM FRIDAY...
FOR LATE TONIGHT THROUGH SATURDAY: THE UPPER JET CORE NOW STRETCHING
FROM THE DAKOTAS DOWN TO NRN MO WILL ROUND THE TROUGH BASE TONIGHT
INTO SATURDAY MORNING... PLACING NC IN ITS RIGHT ENTRANCE REGION.
MEANWHILE THE DEEP LAYER SHEAR BEGINS TO INCREASE... RISING TO 20-25
KTS FROM 06Z-12Z TONIGHT... SO A FEW STORMS EVEN LATER TONIGHT COULD
BECOME STRONG. GIVEN MODEL CONSENSUS THAT PRECIPITABLE WATER WILL
APPROACH 1.9-2.0 INCHES BY SATURDAY MORNING AS WE TAP INTO THE
HIGHER GULF-SOURCE MOISTURE... THE PRESENCE OF AN 850 MB THETA-E
RIDGE FROM AL/GA THROUGH NC... AND WITH THE INCOMING FORCING FOR
ASCENT DUE TO THE INCREASING UPPER LEVEL DIVERGENCE... RISING POPS
INTO THE HIGH CHANCE/LOW LIKELY RANGE SATURDAY STILL LOOKS GOOD AND
REASONABLE... ALTHOUGH I DON`T FORESEE A NONSTOP SOAKING LASTING ALL
DAY... BUT RATHER PERIODS OF SHOWERS AND SCATTERED STORMS. FORECAST
SOUNDINGS INDICATE LAYERS OF DRY AIR UPSTAIRS DURING THE DAY... SUCH
THAT WE SHOULD SEE SOME BREAKS IN THE CLOUDS ESPECIALLY ACROSS THE
SOUTHERN AND EASTERN CWA. LOW LEVEL THICKNESSES WITH A LITTLE BIT OF
SUNSHINE SUPPORT HIGHS OF 87-92.
FOR SATURDAY NIGHT THROUGH SUNDAY NIGHT: IN SHORT... EXPECT
ON-AND-OFF SCATTERED TO NUMEROUS SHOWERS AND STORMS THROUGH THE
LATTER HALF OF THE WEEKEND... WITH PRECIPITABLE WATER REMAINING NEAR
150% OF NORMAL... BOUNDARY LAYER FLOW REMAINING CONFLUENT OUT OF THE
S AND SW KEEPING LOW LEVEL MOISTURE ELEVATED... AND THE MID LEVEL
TROUGH AXIS HOLDING TO OUR WEST. THE LIFTED CONDENSATION LEVEL
ACROSS THE AREA DROPS EARLY SATURDAY NIGHT AND REMAINS IN THE
900-970 MB RANGE THROUGH SUNDAY NIGHT. THIS YIELDS A DEEPENING
LCL-TO-FREEZING-LEVEL LAYER TO 3.5-3.8 KM WHICH FAVORS WARM RAIN
PROCESSES... AND SOME BANDS OF HEAVIER SHOWERS ARE POSSIBLE.
FORECAST SOUNDINGS SHOW MODERATE INSTABILITY PERSISTING... ALTHOUGH
THE DEEP LAYER SHEAR WILL BE MARGINAL AT AROUND 15-20 KTS... AND A
TIGHT LOW LEVEL JET APPEARS TO BE LACKING... SO THE POTENTIAL FOR
STRONG STORMS STILL LOOKS LIMITED BUT THIS WILL NEED TO BE WATCHED.
FURTHER COMPLICATING MATTERS STARTING SUNDAY IS THE DIVERGENT
SOLUTIONS OF THE NAM AND GFS... WITH THE FORMER CLOSING OFF A MID
LEVEL LOW NEAR MEMPHIS BY LATE SUNDAY WHILE THE LATTER HAS THE WEAK
TROUGH SLOWLY LIFTING OUT TO OUR NW. WHILE THE GFS IS INDEED
TRENDING SLOWLY WITH THE EJECTION OF THIS TROUGH... WHICH IS
REASONABLE CONSIDERING THE NORTHWARD RETREAT OF THE WESTERLIES...
THE NAM LOOKS TOO OVERDONE TOO FAR SOUTH. EITHER WAY... NC REMAINS
ON THE WET SIDE OF THIS TROUGH. HIGHS SUNDAY SHOULD BE JUST UNDER
CLIMATOLOGY WITH ABUNDANT CLOUD COVER. LOWS A CATEGORY ABOVE NORMAL
BOTH NIGHTS. -GIH
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...
FOR MONDAY: IF THE GFS/ECMWF SOLUTION OF THE SLOW-MOVING YET
PROGRESSIVE TROUGH AXIS SHIFTING THROUGH THE CENTRAL APPALACHIANS
AND NW NC INTO THE NORTHEAST STATES LATE SUNDAY NIGHT THROUGH MONDAY
ENDS UP CORRECT... WE`RE STILL LIKELY TO SEE SCATTERED TO NUMEROUS
SHOWERS AND STORMS THROUGH MONDAY MORNING. THE GFS SHOWS CONTINUED
MODERATE INSTABILITY AND NORMALIZED CAPE (CAPE FROM LCL TO THE
EQUILIBRIUM LEVEL) EXCEEDS 0.2... FAVORING STRONG UPDRAFTS. WITH
DEEP LAYER SHEAR NEARING 30 KTS AS THE TROUGH AXIS SWEEPS BY TO OUR
NW AND WITH THE MID LEVELS DRYING OUT SOMEWHAT IN THE AFTERNOON...
WE COULD SEE A RISK OF A FEW STRONG STORMS IF THE EXPECTED MORNING
PRECIP AND CLOUDS DON`T HINDER AFTERNOON DESTABILIZATION. HIGHS
SHOULD BE NEAR NORMAL... IN THE UPPER 80S TO NEAR 90.
FOR THE REMAINDER OF THE PERIOD: THE BERMUDA RIDGE ATTEMPTS TO
RETROGRADE BACK TOWARD THE SOUTHEAST COAST AND FL THROUGH MID
WEEK... WHILE SHORTWAVE ENERGY MOVING ACROSS THE US/CANADA BORDER
ALLOWS THE WESTERLIES TO DIP A BIT SOUTHWARD INTO THE NRN GREAT
LAKES/ST LAWRENCE VALLEY/NORTHEAST. VERY LITTLE CHANGES AT THE
SURFACE... WITH THE ATLANTIC-CENTERED SURFACE HIGH HOLDING IN PLACE
AND EXTENDING WSW INTO THE SOUTHEAST COASTAL SECTIONS... WITH A
PERSISTENT PIEDMONT TROUGH OVER CENTRAL/WRN NC AND PRECIPITABLE
WATER REMAINING IN THE 120-140% OF NORMAL RANGE. INASMUCH AS I WOULD
LIKE TO BE ABLE TO DISCERN ONE DAY AS BEING BETTER THAN ANOTHER FOR
SCATTERED MAINLY AFTERNOON/EVENING SHOWERS AND STORMS... AT THIS
RANGE AND WITH MODEL VARIATION IN THE DETAILS... IT REMAINS NEARLY
IMPOSSIBLE. WILL CONTINUE WITH CHANCE POPS... MAINLY AFTERNOON AND
EVENING... TUESDAY THROUGH THURSDAY. GFS/ECMWF THICKNESSES REMAIN
NEAR NORMAL AND TEMPERATURES SHOULD RUN CLOSE TO NORMAL THROUGH THE
PERIOD AS WELL. -GIH
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 705 AM FRIDAY...
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
HOWEVER... ISOLATED TO WIDELY SCATTERED SHOWERS WILL BE POSSIBLE
LATE THIS AFTERNOON AND EVENING AT KINT AND KGSO -- AND PERHAPS AS
FAR EAST AS KRDU -- AS A LEE SIDE SURFACE TROUGH AND GRADUALLY
INCREASING LOW LEVEL MOISTURE MAY PROVE SUFFICIENT TO OVERCOME THE
MID LEVEL CAPPING INVERSION THAT HAS SUPPRESSED DEEP CONVECTION THE
PAST COUPLE OF AFTERNOONS.
OTHERWISE... SCATTERED CUMULUS WILL DEVELOP BY MIDDAY... DEEPEN...
AND EXPAND IN COVERAGE... CONCURRENT WITH AN INCREASE IN MID AND
HIGH LEVEL MOISTURE FROM THE WEST THIS AFTERNOON. THE FLOW AROUND AN
OFFSHORE SURFACE HIGH WILL PROMOTE A CONTINUATION OF SOUTHWESTERLY
SURFACE WINDS BETWEEN 8 AND 12 KNOTS... WITH OCCASIONAL GUSTS TO
BETWEEN 14 AND 18 KTS TODAY... THEN BECOMING LIGHT SOUTHERLY
TONIGHT.
LASTLY... OBSERVED WIND PROFILER DATA INDICATE THE 30 KT LOW LEVEL
JET THAT DEVELOPED OVER CENTRAL NC LAST NIGHT HAS WEAKENED. THE
POTENTIAL EXISTS FOR NOCTURNAL LOW LEVEL JET DEVELOPMENT BETWEEN
1500 AND 2000 FT AGAIN TONIGHT... WITH WINDS WITHIN THE LAYER
ACCELERATING TO BETWEEN 30 AND 40 KNOTS (STRONGEST FROM KRDU
EASTWARD) BETWEEN MIDNIGHT AND 6 AM. WHILE THIS MAY PROMOTE
CONDITIONS JUST SHY OF LLWS CRITERIA... THE ASSOCIATED SHEAR LAYER
MAY PROVIDE FOR A LITTLE TURBULENCE... ESPECIALLY FOR SMALLER
AIRCRAFT.
LOOKING AHEAD... OCCASIONAL MVFR CONDITIONS IN SHOWERS/THUNDERSTORMS
AND MVFR/IFR MORNING STRATUS AND/OR FOG ARE EXPECTED SATURDAY
THROUGH MONDAY... AS AN UPPER LEVEL TROUGH AMPLIFIES OVER THE OHIO
AND TENNESSEE VALLEYS. -MWS
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...MWS
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