Area Forecast Discussion


368 
FXUS61 KLWX 181313
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
913 AM EDT THU SEP 18 2014
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE ACROSS THE MID-ATLANTIC TODAY WHILE AN
UPPER TROUGH AXIS PASSES OVERHEAD. THE HIGH WILL DRIFT ACROSS THE
MID ATLANTIC REGION TO CLOSE OUT THE WEEK...WITH A COLD FRONT
EXPECTED TO CROSS THE AREA LATE SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
A BROAD UPPER-LEVEL TROUGH WILL REMAIN OVER THE REGION THROUGH
THIS AFTERNOON WHILE A WEAK UPPER-LEVEL DISTURBANCE PASSES
THROUGH IN THE FLOW ALOFT. A WEAK COLD FRONT ASSOCIATED WITH THIS
SYSTEM WILL ALSO MOVE THROUGH THIS AFTERNOON INTO THIS EVENING.
MOISTURE WILL BE LIMITED WITH THIS SYSTEM AND FORCING WILL BE
WEAK...BUT A COUPLE SHOWERS ARE POSSIBLE...ESPECIALLY THIS
AFTERNOON AND EVENING ACROSS CENTRAL VIRGINIA. HOWEVER...MOST
PLACES WILL BE DRY AND EVEN FOR LOCATIONS THAT DO GET SHOWERS
PRECIPITATION WILL BE LIGHT. MAX TEMPS WILL BE CLOSE TO CLIMO THIS
AFTERNOON...RANGING FROM THE 60S IN THE MOUNTAINS TO THE MID AND
UPPER 70S IN DOWNTOWN WASHINGTON AND BALTIMORE. A BKN CU DECK IS
EXPECTED TO DEVELOP LATE THIS MORNING AND AFTERNOON. 
HIGH PRESSURE STRENGTHENS ACROSS THE MID-ATLANTIC TONIGHT AND WILL
WEDGE DOWN THE EASTERN SEABOARD. WINDS WILL CONTINUE TO HAVE AN
ONSHORE COMPONENT INTO FRIDAY MORNING. THIS WILL ALLOW MOISTURE
TO POOL INTO THE REGION AND LOW STRATUS ARE EXPECTED ESPECIALLY
NEAR THE BLUE RIDGE MTNS. THE WEDGE WILL HOLD FRIDAY AND EASTERLY
FLOW THROUGH THE LOWEST 0-4 KM WILL LEAD TO MOSTLY CLOUDY
CONDITIONS FOR MUCH OF THE LOOKOUT AREA. THE EXCEPTION BEING NEAR
AND EAST OF THE I-95 CORRIDOR AND ALONG THE ALLEGHENY FRONT WHERE
DRIER AIR WILL BE PRESENT. FCST MAX TEMPS WILL BE BELOW NORMAL DUE
TO CLOUD COVER FRIDAY AND RANGE FROM THE UPPER 60S LOW 70S NEAR
AND WEST OF THE BLUE RIDGE TO THE LOW TO MID 70S ALONG I-95 AND EAST.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WEDGE AXIS REMAINS IN PLACE ACROSS THE MID-ATLANTIC 
FRIDAY NIGHT UNDER WEAK FLOW ALOFT. LOW LEVEL MOISTURE PRESENT WITH 
WEAK ONSHORE FLOW COULD RESULT IN PATCHY GROUND/RIVER FOG DEVELOPING 
OVERNIGHT...AND INTRODUCED MENTION FOR FAVORED AREAS WEST OF THE 
METROS. SURFACE HIGH PRESSURE AXIS SHIFTS SOUTH SATURDAY AS WINDS 
VEER SOUTHEAST...AND SOUTHWEST ABOVE THE BOUNDARY LAYER. DECENT WARM 
AIR ADVECTION ENSUES AS A RESULT AND TEMPERATURES REBOUND BACK TO 
NEAR NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SURFACE WINDS CONTINUE TO VEER SOUTHWEST SATURDAY NIGHT AND SUNDAY. 
WARMING TREND ALSO CONTINUES SUNDAY AHEAD OF APPROACHING COLD FRONT. 
THIS COLD FRONT TRAILING FROM GREAT LAKES/CANADIAN LOW LOOKS TO PUSH 
THROUGH LATE SUNDAY NIGHT INTO MONDAY AS SECONDARY SHORT WAVE ROUNDS 
THE BASE OF UPPER LONG WAVE TROUGH. WILL SEE ISOLATED TO SCATTERED 
SHOWERS AHEAD AND ALONG THE FRONT...THUNDER CHANCES LOOK VERY 
MINIMAL AT THIS TIME WITH VERY LIMITED INSTABILITY PRESENT. GOOD 
COLD AIR ADVECTION WILL BEGIN MONDAY AS THE SHORT WAVE DIVES 
SOUTHEAST OVERHEAD. H85 TEMPS FALL INTO THE SINGLE DIGITS ABOVE ZERO 
CELSIUS AND REMAIN THERE THROUGH THE FIRST FULL DAY OF ASTRONOMICAL 
AUTUMN - TUESDAY. HIGH PRESSURE WITH CONTINUED COOL CONDITIONS ARE 
EXPECTED FOR WEDNESDAY.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING. A BRIEF SHOWER
IS POSSIBLE...BUT MOST PLACES WILL BE DRY. WINDS WILL TURN ONSHORE
BEHIND THE FRONT LATE TONIGHT INTO FRIDAY...SO MVFR CIGS ARE
POSSIBLE DURING THIS TIME...ESPECIALLY FOR CHO-MRB- IAD.
A HIGH PRESSURE WEDGE WILL BE IN PLACE FOR FRIDAY NIGHT 
AND WINDS WILL VEER SOUTHERLY FOR THE WEEKEND AHEAD OF AN 
APPROACHING COLD FRONT. THIS FRONT WILL BRING THE CHANCE OF SHOWERS 
WITH AREAS OF LOWER CIGS SUNDAY NIGHT INTO MONDAY ACROSS THE REGION 
ALONG WITH A WIND SHIFT. COOL HIGH PRESSURE WILL RETURN FOR TUESDAY 
AND WEDNESDAY.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN ACROSS THE WATERS TODAY THROUGH FRIDAY.
ISO-SCT SHOWERS ARE POSSIBLE THIS AFTERNOON AND EARLY EVENING. THE
FLOW WILL TURN ONSHORE TODAY BEFORE VEERING TOWARD THE NORTH-
NORTHEAST BEHIND A COLD FRONT TONIGHT. A PRESSURE SURGE IS
EXPECTED LATE TONIGHT INTO FRIDAY...CAUSING WINDS TO INCREASE. A
SMALL CRAFT ADVISORY IS IN EFFECT FOR THE MARYLAND CHESAPEAKE BAY
AND LOWER TIDAL POTOMAC RIVER DURING THIS TIME. 
HIGH PRESSURE WILL SHIFT SOUTH OF THE REGION FRIDAY NIGHT 
INTO SATURDAY AS WINDS VEER SOUTHEAST. A COLD FRONT WILL PUSH 
THROUGH THE REGION SUNDAY NIGHT AND MONDAY...BRINGING THE CHANCE OF 
SHOWERS WITH GUSTY WINDS. HIGH PRESSURE WILL RETURN TO THE REGION 
FOR TUESDAY AND WEDNESDAY.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES HAVE INCREASED TO ABOUT 1 TO 1.5 FEET ABOVE NORMAL
FROM THE SOUTHERLY FLOW WEDNESDAY. THE FLOW WILL BE LIGHT THROUGH
THIS EVENING...BEFORE INCREASING AND TURNING TOWARD THE NORTHEAST
LATE TONIGHT. WITH NO OFFSHORE FLOW TO PUSH THE WATER OUT OF THE
BAY...THESE TIDAL ANOMALIES ARE LIKELY TO CONTINUE THROUGH
TONIGHT. A COASTAL FLOOD ADVISORY IS IN EFFECT FOR THE HIGH TIDE
CYCLE THIS AFTERNOON AND AGAIN LATE TONIGHT INTO EARLY FRIDAY FOR
ANNE ARUNDEL COUNTY. HOWEVER...CONFIDENCE IN MINOR FLOODING IS
HIGHEST WITH THE LATER OF THE TWO HIGH TIDE CYCLES. 
ELSEWHERE...MINOR TIDAL FLOODING IS POSSIBLE NEAR HIGH TIDE LATE
TONIGHT INTO EARLY FRIDAY. HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH
FOR A COASTAL FLOOD ADVISORY AT THIS POINT. 
AN ONSHORE FLOW IS EXPECTED TO CONTINUE THROUGH SUNDAY...CAUSING
ELEVATED WATER LEVELS AND THE POSSIBILITY OF MINOR TIDAL FLOODING. 
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 5 AM EDT FRIDAY FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO NOON EDT FRIDAY FOR 
     ANZ530>534-537-539>541-543.
&&
$$
SYNOPSIS...HAS
NEAR TERM...HAS
SHORT TERM...AEB
LONG TERM...AEB
AVIATION...HAS/AEB
MARINE...HAS/AEB
TIDES/COASTAL FLOODING...BJL