795
FXUS61 KLWX 161603 AAB
AFDLWX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1203 PM EDT WED OCT 16 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO APPROACH FROM THE OHIO VALLEY...
SLIDING LARGELY TO THE NORTH OF THE AREA. ANOTHER WAVE OF LOW
PRESSURE WILL MOVE ACROSS THE REGION LATE THURSDAY INTO EARLY
FRIDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN BEFORE A SERIES OF
WEAK WAVES OF LOW PRESSURE INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...COASTAL FLOOD ADZY FOR ANNE ARUNDEL CO FOR THIS AFTN'S
H.T. CYCLE.
PREV DISC...
IN ORDER TO DISCUSS TODAY'S WX...HAVE TO LINK IT TO THE POTENTIAL
PATTERN SHIFT/TREND THAT WE'LL SEE OVER THE NEXT WEEK - IF NOT
LONGER. A COUPLE OF DEEP CANADIAN TROUGHS WILL DIG DOWN INTO THE
NRN SECTIONS OF THE CONUS - ONE THRU THE END OF THE WEEK AND
ANOTHER POTENTIALLY DURING THE MIDDLE OF NEXT WEEK.
TODAY...A WEAKENING COLD FRONT BEING DRAGGED ALONG BY A NEARLY
DISSIPATED LOW PRESSURE SYSTEM OVER NRN NEW ENGLAND. PRECIP ALONG
THE FRONT CONTINUES ACROSS PORTIONS OF THE UPPER MIDWEST...BUT THE
SUPPORT TO PUSH THIS ACTIVITY ACROSS OUR REGION IS BEING MITIGATED
BY THE MULTIPLE SYNOPTIC-SCALE FEATURES OFF THE COAST. THE COLD
FRONT ITSELF CURRENTLY STRETCHES FROM NEW ENGLAND TO THE SRN
PLAINS. AS THE PARENT LOW TAKES OFF TO THE NE...THE FRONT WILL
EFFECTIVELY SPLIT W/ THE NRN HALF SLIDING AWAY FROM THE MID
ATLC...THE OTHER HALF GETTING LEFT BEHIND OVER THE TENN VLY/DEEP
SOUTH. THIS PORTION WILL EVENTUALLY GET PICKED UP BY A SECONDARY
UPPER WAVE THAT IS STILL BACK ACROSS THE CNTRL PLAINS.
PLENTY OF CLOUD COVER TODAY...THOUGH THE MORNING SOLID SHIELD OF
LOW STRATUS WILL BEGIN TO BREAK UP AND SOME SUN WILL PEAK THRU AT
TIMES THIS AFTN. A LIGHT SLY WIND WILL DEVELOP THIS AFTN AS THE
WEAK COLD FRONT SLIDES BY TO THE NORTH...HELPING TO INCREASE THE
TEMPS A COUPLE OF DEG...W/ MANY AREAS PEAKING IN THE L70S LATER
THIS AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
SKIES SHOULD BE CLDY TNGT AS THE NEXT WAVE OF LOW PRESSURE DRAWS
CLOSER. CHC POPS W OF THE APLCHNS. LOWS IN THE 50S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
A COLD FRONT WILL MOVE INTO THE AREA THURSDAY BEFORE PASSING
THROUGH THURSDAY NIGHT. A SHORTWAVE MOVING THROUGH IN THE
SOUTHWEST FLOW ALOFT WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP
ALONG THE FRONT. AS OF NOW IT APPEARS THAT THE STEADIEST RAIN
ASSOCIATED WITH THE SURFACE LOW WILL REMAIN TO OUR NORTH.
HOWEVER...THERE WILL BE PLENTY OF MOISTURE AND LIFT FROM THE COLD
FRONT TO TRIGGER SOME SHOWERS ACROSS OUR AREA DURING THIS TIME.
THE BEST CHANCE FOR PRECIPITATION WILL BE THURSDAY AFTERNOON AND
EVENING.
THE COLD FRONT WILL MOVE OFFSHORE LATE THURSDAY NIGHT. COOLER AND
DRIER CONDITIONS ARE EXPECTED BEHIND THE FRONT. MIN TEMPS WILL
RANGE FROM THE LOWER 40S IN THE POTOMAC HIGHLANDS TO THE MID AND
UPPER 50S IN WASHINGTON AND BALTIMORE.
HIGH PRESSURE WILL BUILD OVERHEAD FRIDAY BEHIND THE COLD FRONT...
BRINGING DRY AND SEASONABLE CONDITIONS. HIGH PRESSURE WILL REMAIN
OVERHEAD FRIDAY NIGHT...PROVIDING A GOOD SETUP FOR RADIATIONAL
COOLING. PATCHY FROST POSSIBLE IN THE SHELTERED VALLEYS OF THE
POTOMAC HIGHLANDS.
AN UPPER-LEVEL TROUGH WILL DEVELOP OVER THE GREAT LAKES AND
CENTRAL CONUS SATURDAY. AN UPPER-LEVEL DISTURBANCE ASSOCIATED WITH
THE TROUGH WILL PASS BY TO OUR NORTH AND WEST. HOWEVER...A
REINFORCING COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL MOVE
THROUGH SATURDAY INTO SUNDAY. LITTLE IF ANY PRECIPITATION WILL BE
ASSOCIATED WITH IT.
CANADIAN HIGH PRESSURE WILL BUILD OVERHEAD BEHIND THE COLD FRONT
EARLY NEXT WEEK...BRINGING DRY AND CHILLY CONDITIONS. THE HIGH WILL
MOVE OFF THE COAST DURING THE MIDDLE PORTION OF NEXT WEEK.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
XTNSV CLD CVR TDA/TNGT AHD OF A CD FNT RUNNING THRU THE OH VLLY.
THIS HAS LIMITED MRNG FOG BUT HAS KNOCKED CIGS INTO MVFR RANGE.
BLV THERE WL BE SOME IMPRVMNT IN CLD HGT THIS MRNG..."LOW VFR"
LATER THIS MRNG/THIS AFTN...THEN LOWERING AGN TNGT.
A COLD FRONT WILL APPROACH THE TERMINALS THURSDAY BEFORE PASSING
THROUGH THURSDAY EVENING. MVFR CIGS AND SHOWERS ARE POSSIBLE DURING
THIS TIME. HIGH PRESSURE WILL RETURN OVERNIGHT THURSDAY AND
FRIDAY...BRINGING VFR CONDITIONS ALONG WITH NORTHWEST WINDS.
A REINFORCING COLD FRONT WILL PASS THROUGH SATURDAY INTO
SUNDAY...BUT LITTLE MOISTURE WILL BE ASSOCIATED WITH THE BOUNDARY.
&&
.MARINE...
WINDS BLO SCA VALUES TDA/TNGT.
A COLD FRONT WILL APPROACH THE WATERS THURSDAY BEFORE PASSING
THROUGH THURSDAY NIGHT. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED
FOR PORTIONS OF THE WATERS THURSDAY NIGHT INTO FRIDAY.
HIGH PRESSURE WILL BUILD OVERHEAD LATER FRIDAY...BUT A REINFORCING
COLD FRONT MAY MOVE THROUGH SATURDAY INTO SUNDAY. WIND GUSTS MAY
COME CLOSE TO SCA CRITERIA SUNDAY. HIGH PRESSURE WILL BUILD OVER THE
WATERS EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
SOUTHERLY WINDS ARE EXPECTED TODAY AND WINDS MAY INCREASE AHEAD
OF A COLD FRONT THURSDAY. WATER LEVELS WILL BE CLOSE TO MINOR
FLOODING THRESHOLDS NEAR TIMES OF HIGH TIDE TODAY THROUGH THURSDAY
NIGHT. CURRENTLY MONITORING THE DC AREA AND ANNAPOLIS TRENDS AS
THEY APPROACH THEIR LATE AFTN H.T. CYCLE. CURRENT TRENDS WILL TAKE
LEVELS BRIEFLY INTO MINOR C.F. THEN...BUT THERE COULD BE SOME
SLIGHT DECREASES IN ANOMALIES IN THE NEXT FEW HRS THAT MAY DROP
THESE LEVELS BELOW CRIT.
AN OFFSHORE FLOW SHOULD CAUSE LOWER WATER LEVELS FRIDAY THROUGH
THE WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...GMS
PREV DISCUSSION...WOODY!/BJL