390
FXUS62 KRAH 061145
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
745 AM EDT SUN JUL 6 2008
SYNOPSIS
A STATIONARY FRONT WILL REMAIN STALLED ACROSS VIRGINIA AND WEST
VIRGINIA... WITH HIGH PRESSURE OFF THE CAROLINA COAST. A WARM AND
HUMID AIRMASS ACROSS THE REGION WILL RESULT IN THE DEVELOPMENT OF
MAINLY AFTERNOON AND EVENING THUNDERSTORMS THROUGH TUESDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 300 AM SUNDAY...
PRECIPITATION OVER THE NORTHWEST PIEDMONT WILL PERSIST THROUGH THE
MORNING WITH THE STEADY STREAM FROM NORTHERN GEORGIA AND WESTERN
SOUTH CAROLINA... PRECIP MORE SCATTERED OVER THE REST OF THE CWA.
NOT MUCH CHANGE IN THE FORECAST THROUGH TONIGHT... OVER THAT OF
SATURDAY. UPPER LEVEL TROUGH REMAINS WEST OF THE AREA PROVIDING
MOISTURE FEED THROUGH ALL LEVELS. 40 TO 50 KNOTS UPPER LEVEL JET
WEST OF THE REGION WILL PROVIDE GOOD LIFT. PRECIP WATER VALUES ONCE
AGAIN AROUND 2 INCHES... WITH LI'S IN THE -3 TO -6 RANGE... CAPE
1500 TO 2300 J/KG. ALL THIS WILL ADD UP TO ANOTHER ACTIVE DAY. ONE
CONCERN TODAY IS HEAVY RAIN OVER THE NORTHEAST... SINCE ITS HAD
UPWARDS OF 5 INCHES OF RAIN OVER THE PAST FEW DAYS. ADDITIONAL RAIN
COULD LEAD TO SOME FLOODING PROBLEMS... SO THIS AREA WILL BE
MONITORED FOR ANY SLOW MOVING STORMS.
HIGHS TODAY IN THE 80S TO AROUND 90 IN THE SOUTHEAST. LOWS TONIGHT
IN THE 60S TO LOWER 70S.
SHORT TERM /MONDAY THROUGH TUESDAY/
AS OF 300 AM SUNDAY...
MOIST UNSTABLE CONDITIONS CONTINUE OVER THE AREA. THE PRECIP WATER
VALUES DO LOWER SOME ON MONDAY AS WINDS BECOME MORE SOUTHERLY...
HOWEVER AS WINDS VEER TO MORE SOUTHWEST VALUES CREEP BACK TO 1.75 TO
NEAR 2 INCHES FOR TUESDAY. THIS COMBINE WITH UPPER LEVEL TROUGHS
STARTING WORK THEIR WAY ACROSS THE AREA AND A WARMING TREND OVER THE
REGION... SHOWERS AND THUNDERSTORMS WILL BE THE ORDER OF THE DAY
THROUGH THE BEGINNING OF THE WORK WEEK. HIGHS WILL BE IN THE LOW
90S. LOWS MONDAY NIGHT WILL BE IN THE 60S.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
AS OF 320 AM SUNDAY...
THE INFLUENCE OF A WEAK SURFACE RIDGE THAT IS IN PLACE ACROSS
CENTRAL NORTH CAROLINA DURING THE DAY TUESDAY BEGINS TO WANE IN
FAVOR OF INCREASED SURFACE TROUGHINESS OVER THE STATE BY WEDNESDAY.
THE LATEST GFS SHOWS A SURFACE TROUGH DEVELOPING AND REMAINING OVER
OR NEAR CENTRAL NORTH CAROLINA THROUGH THE REST OF THE WORK WEEK AND
THE START OF NEXT WEEKEND AS DEEP MOISTURE REMAINS THE RULE OVER THE
FORECAST AREA. THE 00Z GFS HAS PRECIPITABLE WATER VALUES...
OVERALL...FROM 1.75 INCHES TO 2 INCHES DURING THE PERIOD. IF THE
GFS VERIFIES...WEAKLY DIFFLUENT UPPER FLOW...WITH THE MOISTURE AND
AVAILABLE SURFACE CONVERGENCE...SHOULD CONTINUE TO ALLOW AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS. THE ONE DAY IN THIS LONG-TERM
PERIOD WHERE THE CHANCES FOR SHOWERS AND STORMS MAY BE REDUCED SOME
OVER PART OF CENTRAL NORTH CAROLINA IS THURSDAY...WHEN THE GFS
ACTUALLY DIMINISHES PRECIPITABLE WATER VALUES TO ONLY AN INCH TO 1.5
INCHES ACROSS NORTHERN ZONES AS THE UPPER FLOW BECOMES MORE
CONFLUENT. WOULD NOT BE SURPRISED IF THIS SUBTLTY CHANGES OVER THE
COURSE OF TIME AND STILL LEFT CHANCE POPS IN FOR THURSDAY...THOUGH
SLIGHTLY LESS...ESPECIALLY NORTH...THAN WEDNESDAY AND FRIDAY.
MADE NO CHANGES TO HIGHS AND LOWS AT THIS TIME. 1000-850MB
THICKNESSES WOULD ON SOME DAYS SUPPORT WARMER TEMPERATURES THAN
CURRENTLY FORECAST. HOWEVER...THIS COULD BE OFFSET BY THE MOIST AIR
MASS AND AMPLE CLOUD COVER. SURFACE DEW POINTS ARE EXPECTED TO
REMAIN IN THE MID 60S TO LOWER 70S...CONSISTENT WITH ANTICIPATED
OVERNIGHT LOWS DURING THE PERIOD.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
AS OF 745 AM SUNDAY...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS HAD GRADUALLY
DIMINISHED IN INTENSITY AND COVERAGE DURING THE EARLY MORNING
HOURS...WHILE MANY LOCATIONS OUTSIDE OF THE SANDHILLS AND SOUTHERN
COASTAL PLAIN WERE IN IFR CONDITIONS PRIMARILY DUE TO LOW CLOUDS.
THE VERY MOIST BOUNDARY LAYER WAS COINCIDENT WITH THE NAM BUFR
SOUNDINGS WHICH WERE SUPPORTIVE OF IFR CONDITIONS IN LOW CLOUDS
ACROSS CENTRAL NORTH CAROLINA. AS MIXING DEVELOPS DURING THE
MORNING...CEILINGS SHOULD RISE THROUGH MVFR AND TO VFR. HOWEVER...
WITH HIGH PRECIPITABLE WATER VALUES OF 1.75 TO 2 INCHES...GOOD
DIFFLUENCE ALOFT WITH THE UPPER TROUGH IN PLACE TO OUR WEST...
CENTRAL NORTH CAROLINA BEING IN THE RIGHT ENTRANCE REGION OF A
55-65KT 250MB JET...AND AMPLE INSTABILITY AS SHOWN BY NAM FORECAST
SOUNDINGS...ONCE AGAIN EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO
REDEVELOP ACROSS THE REGION THIS AFTERNOON CONTINUING INTO THE
OVERNIGHT HOURS. SURFACE WINDS SHOULD TEND TO VEER FROM LIGHT
SOUTHEAST TO SOUTH AND SOUTHWEST AT 10KT OR LESS...AND WINDS ALOFT
THROUGH 3K FEET SHOULD BE 20KT OR LESS. NAM BUFR SOUNDINGS AND MOS
GUIDANCE ARE NOT DEPICTING AS MUCH POTENTIAL FOR LOW CLOUDS EARLY
MONDAY MORNING AS WAS OCCURRING THIS SUNDAY MORNING...THOUGH THE
TREND FOR THIS WILL CERTAINLY NEED TO EVALUATED FURTHER OVER TIME
GIVEN THE MOIST AIR MASS AND MODEST INCREASE IN WINDS OFF THE
SURFACE LATE TONIGHT.
WEATHER PATTERN CHANGES LITTLE THROUGH MONDAY...ALTHOUGH
PRECIPITABLE WATER VALUES WILL DIMINISH SLIGHTLY IN THE TRIAD.
AVIATION INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED STORMS ON
MONDAY. FROM TUESDAY THROUGH THURSDAY...THERE WILL CONTINUE TO BE A
CHANCE OF SHOWERS AND THUNDERSTORMS IN A MOIST AIR MASS. SURFACE
RIDGING BUILDING IN WEAKLY FROM THE EAST MAY RESULT IN A LESSER
AMOUNT OF STORM COVERAGE AND CHANCES TUESDAY...WITH A SURFACE TROUGH
MOVING IN FOR MID WEEK HELPING TO INCREASE CHANCES ONCE AGAIN BY
WEDNESDAY. IF THE GFS MODEL VERIFIES...NORTHERN TAF SITES MAY BE
DRIER AND SLIGHTLY MORE STABLE THURSDAY VERSUS KFAY IN SLIGHTLY MORE
CONFLUENT FLOW ALOFT.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...RHJ
NEAR TERM...RHJ
SHORT TERM...RHJ
LONG TERM...DJF
AVIATION...DJF
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