XXXX00 KCTP 131018
WRKAFD

THE START OF THE SHORT TERM PERIOD WILL BE DRY AND COLD AS A LARGE 
AREA OF HIGH PRESSURE DRIFTS EAST-NORTHEAST FROM THE MID MISSISSIPPI 
VALLEY TO THE NEW ENGLAND STATES.

AS THE HIGH DRIFTS RIGHT OVER THE STATE WEDNESDAY NIGHT, STRONG 
RADIATIONAL COOLING OF THE GROUND WILL OCCUR (AT LEAST DURING THE 
FIRST HALF OF THE NIGHT) WITH WINDS STAYING LIGHT AND VARIABLE AND 
JUST A THIN VEIL OF CIRROSTRATUS SPREADING NORTHEAST ACROSS MUCH OF 
THE REGION. 

SERLY LLVL FLOW WILL INCREASE QUICKLY AFTER MIDNIGHT WED NIGHT 
ACROSS THE WESTERN MTNS AS THE PRESSURE GRADIENT TIGHTENS. CLOUDS 
WILL ALSO LOWER/THICKEN TO AN ALTOSTRATUS DECK ACROSS THAT PART OF 
THE STATE. 

THICKENING MID LEVEL CLOUD DECK WILL OVERSPREAD THE ENTIRE CWA 
THURSDAY MORNING, FOLLOWED BY PRECIPITATING NS CLOUDS SPREADING 
NORTH TO NEAR THE INTERSTATE 80 CORRIDOR BY EARLY AFTERNOON. 

PRECIP TYPE (AND SNOW/ICE AMOUNTS) WILL BE THE BIGGEST CONCERNS WITH 
THIS UPCOMING EARLY SEASON/HIGH IMPACT WINTER STORM. LLVL WET BULB 
PROFILES ARE NEAR TO BELOW ZERO THROUGH THE ENTIRE AIR COLUMN 
THROUGH MUCH OF THURSDAY WITH ONLY A RELATIVELY THIN WEDGE OF 
SLIGHTLY ABOVE FREEZING AIR WITHIN ABOUT THE 3-6 KFT AGL LAYER. THE 
MAIN IMPACT FROM THIS WEAK WARM WEDGE WILL BE TO PROVIDE PERIODS OF 
SLEET (OR EVEN SOME FREEZING RAIN) IF THE SURGE OF WARMER AIR ALOFT 
FORM THE SOUTHEAST IS SLIGHTLY STRONGER/DEEPER.  

THE ORIGINAL SFC LOW TRACKING NE ACROSS THE LOWER MISS RIVER VALLEY 
WILL WEAKEN STEADILY AS IT HEADS NE AND OVER THE LOWER OHIO VALLEY. 
STRENGTHENING UPPER DIFFLUENCE AHEAD OF A POTENT NEGATIVE TILT UPPER 
LOW MOVING FROM THE LOWER MISS VALLEY LATE WED NIGHT, TO SOUTHERN PA 
BY DAYBREAK FRIDAY WILL HELP TO QUICKLY FORM/STEADILY STRENGTHEN A 
COAST LOW THAT WILL MOVE FROM JUST EAST OF HILTON HEAD ISLAND, SC 
AROUND DAYBREAK THURSDAY, TO JUST OFF THE COAST OF ATLANTIC CITY AT 
12Z FRIDAY. 

AT THIS POINT, THIS LOOKS LIKE A TYPICAL NW TO SE STRATIFIED HEAVY 
WET SNOW ACROSS THE NORTHERN AND WESTERN MTNS, WITH MIXED WET 
SNOW/SLEET/RAIN NEAR THE I-80 CORRIDOR, AND A SHORTER PERIOD OF WET 
SNOW AT THE BEGINNING AND END OF THE EVENT (SANDWICHING A LONGER 
DURATION OF A COLD RAIN - WITH POCKETS OF SLEET AND FREEZING RAIN) 
ACROSS THE LOWER SUSQ VALLEY.

ALTHOUGH THICKNESSES AND LOW-LEVEL PROFILES ARE BORDERLINE WITH 
RESPECT TO TEMPS/WETBULBS, MODERATE TO HEAVY ACCUMS OF SNOW (WITH A 
LIGHT LAYER OF SLEET AND OR FREEZING RAIN) APPEAR LIKELY BASED ON A 
STRONG CONSENSUS OF STORM TRACK BETWEEN MULTIPLE OPERATIONAL MODELS 
AND ENSEMBLE FORECAST SYSTEMS (EFS). 

LOOK FOR THE POTENTIAL OF BORDERLINE WARNING AMOUNTS OF SNOW ACROSS 
THE HIGHER ELEVATIONS OF THE CENTRAL AND NORTHERN MTNS, WITH 
ANYWHERE FROM 1 TO 4 INCHES OF SNOW POSSIBLE (DEPENDING ON THE EXACT 
LLVL THERMAL PROFILES) IN THE CENTRAL VALLEYS AND SUSQUEHANNA 
REGION. GENERALLY 1.5 INCHES OR LESS IS EXPECTED ACROSS THE REGION 
TO THE SE OF THE I-81 CORRIDOR FROM THURSDAY MIDDAY TO FRIDAY 
MORNING.

THIS TRACK OF THE SFC AND UPPER LOW WILL BE OPTIMAL FOR A ONE-TWO 
PUNCH OF WARM, THEN COLD  CONVEYOR BELT PRECIP ACROSS MOST OR ALL OF 
THE CWA.

THE STORM WILL END QUICKLY FROM WEST TO EAST FRIDAY MORNING AS THE 
UPPER TROUGH BECOMES SHEARED/FLATTENS AS IT FEELS THIS INFLUENCE OF 
THE STRONG NORTHERN STREAM WEST TO NW FLOW ALOFT. 

FRIDAY WILL FEATURE SOME LAKE EFFECT SNOW SHOWERS ACROSS THE NW 
MTNS, BUT ADDITIONAL ACCUMULATIONS SHOULD BE UNDER ADVISORY CRITERIA 
OF 3 INCHES IN MOST PLACES NEAR AND TO THE WEST OF KBFD.

GUSTY WESTERLY WINDS AND SLIGHTLY MODERATING TEMPS WILL HELP TO MELT 
A GOOD PERCENTAGE OF THE SNOW SE OF THE ALLEGHENY FRONT.  

DRY AND CHILLY CONDITIONS WILL PERSIST THROUGH SAT NIGHT BEFORE 
ADDITIONAL NORTHERN STREAM ENERGY DIVES SE AND PUSHES A REINFORCING 
SHOT OF COLDER AIR ACROSS THE REGION LATE IN THE WEEKEND AND EARLY 
NEXT WEEK. 

PERSISTENT, BELOW NORMAL TO MUCH BELOW NORMAL TEMPS WILL BE THE RULE 
FOR THE NEXT 7-8 DAYS.