573
FXUS61 KILN 231048
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
648 AM EDT SAT MAR 23 2019
SYNOPSIS
HIGH PRESSURE WILL MOVE INTO THE OHIO VALLEY TODAY, BRINGING
DRY AND SUNNY CONDITIONS THROUGH SUNDAY MORNING. LATER ON SUNDAY
AND INTO MONDAY, A WEAKENING AREA OF LOW PRESSURE WILL MOVE
SOUTHEAST THROUGH THE OHIO VALLEY, BRINGING A CHANCE OF RAIN.
HIGH PRESSURE WILL MOVE INTO THE AREA AGAIN ON TUESDAY, WITH DRY
WEATHER EXPECTED THROUGH MOST OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
SURFACE ANALYSIS INDICATES AN AREA OF HIGH PRESSURE CENTERED
NEAR LAKE MICHIGAN. THIS HIGH IS EXPANSIVE, INFLUENCING
CONDITIONS ALL THE WAY FROM LAKE WINNIPEG TO THE GULF COAST. THE
OHIO VALLEY IS CAUGHT IN BETWEEN TWO UPPER LEVEL DISTURBANCES,
WITH A MID-LEVEL LOW DEPARTING THE NORTHEASTERN STATES TO THE
EAST, AND A TROUGH SLOWLY DEVELOPING IN THE ROCKIES. A NARROW
RIDGE IN BETWEEN THE TWO SYSTEMS IS NOW MOVING INTO THE OHIO
VALLEY, WITH HEIGHTS BEGINNING TO RISE -- AN INDICATION OF WARM
ADVECTION IN THE 850MB-700MB LAYER. ANY LAST COLD ADVECTION
STRATOCUMULUS IS NOW WELL OFF TO THE EAST, WITH CIRRUS ON THE
BACK SIDE OF THE RIDGE STILL WELL UPSTREAM. WITH THIS VERY DRY
AIR MASS IN PLACE -- PRECIPITABLE WATER VALUES ARE UNLIKELY TO
REACH EVEN TWO TENTHS OF AN INCH -- IT IS VERY LIKELY THAT SKIES
WILL REMAIN COMPLETELY CLEAR TODAY. LATE IN THE DAY AND HEADING
INTO THE EVENING, SOME CIRRUS WILL BEGIN TO MOVE INTO THE AREA.
WITH THE DRY AND SUNNY CONDITIONS, TEMPERATURES SHOULD RESPOND
WELL, AND MAX TEMPS ARE EXPECTED TO REACH THE UPPER 40S TO
MIDDLE 50S. IF ANYTHING, THESE NUMBERS COULD EVEN BE A COUPLE
DEGREES TOO LOW, THOUGH THEY REPRESENT A SLIGHT INCREASE FROM
THE PREVIOUS FORECAST. MAV/GFS NUMBERS LOOK A LITTLE MORE
REASONABLE (AND WARMER) THAN NAM/SREF MEAN NUMBERS.
SHORT TERM /SUNDAY/
A DEAMPLIFYING RIDGE AXIS WILL BE DIRECTLY OVERHEAD THIS
EVENING OVER THE ILN FORECAST AREA, WITH SURFACE HIGH PRESSURE
BEGINNING TO MOVE OFF TO THE SOUTHEAST. ON THE BACK SIDE OF THE
RIDGE, CIRRUS CLOUDS ARE EXPECTED TO BE SPILLING INTO THE
REGION, BUT THE LOW LEVELS WILL REMAIN VERY DRY HEADING INTO THE
OVERNIGHT HOURS. RADIATIONAL COOLING CONDITIONS WILL ACTUALLY
BE BETTER AT THE START OF THE OVERNIGHT PERIOD, BEFORE THE
CLOUDS BECOME A LITTLE THICKER, AND BEFORE SOME LIGHT SSE FLOW
BEGINS TO DEVELOP AS THE HIGH MOVES AWAY. FOR THIS REASON, MIN
TEMPS MAY ARRIVE CLOSE TO 06Z, WITH STEADY OR SLIGHTLY WARMING
TEMPERATURES THROUGH SUNDAY MORNING. DEPENDING ON HOW THIS
TIMING ACTUALLY WORKS OUT, THE MIN TEMPS COULD VARY A BIT FROM
THIS FORECAST, BUT ARE GENERALLY EXPECTED TO BE IN THE LOWER TO
MIDDLE 30S.
THE MID-LEVEL FLOW OVER THE EASTERN HALF OF THE COUNTRY WILL BE
FLATTENING OUT ON SUNDAY, AS A WEAKENING MID-LEVEL LOW OPENS
INTO A WAVE OVER THE MIDDLE MISSISSIPPI VALLEY REGION. PERHAPS
AS A RESULT OF THIS INCREASINGLY DAMPENED SOLUTION, THE FORWARD
PROGRESSION OF THIS SYSTEM IS BEING HANDLED A BIT FASTER IN
RECENT MODEL RUNS, WITH THE INITIAL BATCH OF WARM ADVECTION
PRECIPITATION IMPINGING ON THE ILN FORECAST AREA AS EARLY AS
12Z-15Z ON SUNDAY MORNING. POP TIMING WAS ADJUSTED TO ACCOUNT
FOR THIS, AND THERE WERE SOME CHANGES TO TEMPERATURE GRIDS AS
WELL, WITH MORE OF A GRADIENT IN PLACE THAN BEFORE. AS IT LOOKS
NOW, ONLY THE SOUTHEASTERN SECTIONS OF THE ILN CWA APPEAR LIKELY
TO REMAIN OUT OF THE THICKER MID-LEVEL CLOUDS AND POTENTIAL
PRECIPITATION THROUGH THE AFTERNOON, AND THESE AREAS WILL LIKELY
SEE THE WARMEST TEMPERATURES -- CLOSE TO 60 DEGREES. 50S ARE
EXPECTED ELSEWHERE.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
FOR SUNDAY NIGHT, A S/WV WILL GET NUDGED EAST BY A LARGE SCALE
MID LEVEL TROUGH DIGGING SOUTHWARD INTO THE GREAT LAKES AND NEW
ENGLAND. WEAK LOW PRESSURE WITH THE S/WV WILL COMBINED WITH A
SOUTHWARD MOVING COLD FRONT TO BRING CATEGORICAL POPS TO THE
REGION. MODELS HAVE TRENDED A LITTLE COLDER WITH AIR FILTERING
IN FROM THE NORTH, SO SOME OF THE PRECIPITATION ACROSS THE FAR
NORTH MAY MIX WITH A LITTLE SNOW LATE. LOWS WILL RANGE FROM THE
LOWER 30S FAR NORTH TO THE UPPER 40S FAR SOUTH.
ON MONDAY, THE WEAK LOW AND COLD FRONT WILL CONTINUE TO PUSH
SOUTHEAST. THIS WILL ALLOW PCPN TO TAPER OFF FROM THE NORTH
DURING THE DAY AS DRIER AIR FILTERS IN. AGAIN, MODELS HAVE
TRENDED A LITTLE COLDER WITH THE LOW LEVELS OF THE ATMOSPHERES,
AND A LITTLE BIT OF SNOW MAY MIX IN ALONG AND NORTH OF I-70
BEFORE PCPN TAPERS OFF BY AFTERNOON. IT SHOULD REMAIN IN LIQUID
FORM ACROSS THE SOUTH. TEMPERATURES WILL BE TRICKY GIVEN INITIAL
CAA, BUT WITH CLEARING SKIES FROM THE NORTH AND SOME SUNSHINE
EXPECTED FOR ALL LOCATIONS BEFORE THE SUN SETS, THE SUNSHINE MAY
OFF SET THIS CAA SLIGHTLY. WITH A BRISK NORTHEAST WIND GUSTING
BETWEEN 20 AND 30 MPH, HIGHS WILL RANGE FROM THE LOWER 40S NORTH
TO NEAR 50 SOUTH.
FOR MONDAY NIGHT INTO TUESDAY, A LARGE AREA OF SURFACE HIGH
PRESSURE ASSOCIATED WITH VERY DRY AIR WILL BUILD SOUTH INTO THE
GREAT LAKES AND OHIO VALLEY. MAINLY CLEAR SKIES MONDAY NIGHT
WILL GIVE WAY TO MOSTLY SUNNY SKIES ON TUESDAY. DESPITE THE
SUNSHINE, TEMPERATURES WILL BE BELOW NORMAL FOR LATE MARCH AS
COOL AIR WILL BE IN PLACE ACROSS THE REGION. AFTER LOWS IN THE
20S, HIGHS WILL RANGE FROM THE LOWER 40S NORTH TO THE MID/UPPER
40S SOUTH.
FOR TUESDAY NIGHT INTO WEDNESDAY, ALTHOUGH THE CENTER OF THE
SPRAWLING HIGH WILL MOVE EAST TO NEW ENGLAND THEN EVENTUALLY OFF
THE NEW ENGLAND COAST, IT WILL STILL EXTEND WESTWARD INTO THE
GREAT LAKES AND OHIO VALLEY. AFTER A COLD START IN THE 20S ON
WEDNESDAY MORNING, TEMPERATURES WILL BEGIN TO MODERATE WITH
PLENTY OF SUNSHINE WEDNESDAY. HIGHS WEDNESDAY WILL RANGE FROM
NEAR 50 NORTH TO THE MID/UPPER 50S SOUTH.
A MID LEVEL RIDGE AXIS WILL MOVE FROM THE PLAINS TO THE
APPALACHIAN REGION WEDNESDAY NIGHT INTO THURSDAY. AT THE SAME
TIME, SURFACE HIGH PRESSURE WILL CONTINUE TO MOVE SLOWLY OFF THE
NEW ENGLAND COAST WHILE A FRONTAL SYSTEM BEINGS TO ORGANIZE
ACROSS THE MID SECTION OF THE U.S. THIS PATTERN WILL ALLOW
CLOUDS TO INCREASE ON THURSDAY. INCREASING SOUTHERLY FLOW
BETWEEN THE TWO AFOREMENTIONED SYSTEMS WILL ALLOW TEMPERATURES
TO WARM INTO THE 60S ALL LOCATIONS.
FOR THURSDAY NIGHT INTO FRIDAY, MODELS CONTINUE TO DISAGREE ON
THE SPEED AND EVOLUTION OF THE NEXT WEATHER SYSTEM TO AFFECT OUR
REGION. GIVEN A DEVELOPING AMPLIFIED MID LEVEL FLOW PATTERN,
WILL CONTINUE WITH A SLOW INCREASE OF CLOUDS AND CHANCES OF RAIN
FROM WEST TO EAST THROUGH THIS PERIOD. AFTER LOWS IN THE 40S,
HIGHS WILL ONCE AGAIN WARM INTO THE 60S FRIDAY IN A REGIME OF
STRONG SOUTHERLY FLOW.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. SKIES HAVE
CLEARED OUT, AND SHOULD REMAIN CLEAR WELL INTO THE DAY TODAY.
NW WINDS WILL GENERALLY REMAIN BELOW 10 KNOTS, BEFORE BECOMING
LIGHT AND VARIABLE DURING THE EVENING.
HIGH AND MID LEVEL CLOUDS WILL BEGIN TO INCREASE TONIGHT, BUT
PRECIPITATION APPEARS LIKELY TO HOLD OFF UNTIL LATER ON SUNDAY.
WINDS ON SUNDAY WILL PICK UP FROM THE SOUTH / SSW, INCREASING TO
AROUND 10 KNOTS.
OUTLOOK...MVFR CONDITIONS ARE POSSIBLE ON SUNDAY NIGHT AND
MONDAY.
ILN WATCHES/WARNINGS/ADVISORIES
OH...NONE.
KY...NONE.
IN...NONE.
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...HATZOS
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