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000
FXUS63 KGRR 310457
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1157 PM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 PM EST FRI JAN 30 2015

LOW PRESSURE WILL BRING SOME SNOW ON SUNDAY WITH THE HIGHEST
AMOUNTS ACROSS FAR SOUTHERN LOWER MICHIGAN NEAR THE INDIANA
BORDER. VERY COLD WEATHER IS EXPECTED MONDAY WITH MORE SNOW
POSSIBLE TUESDAY NIGHT AND WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM EST FRI JAN 30 2015

THE STORM ON SUNDAY IS THE MAIN FORECAST PROBLEM IN THE NEAR TERM.
12Z MODEL GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR 4 OR MORE
INCHES OF SNOW ACROSS THE I-94 CORRIDOR BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. HELD OFF ON HEADLINES FOR NOW BASED ON UNCERTAINTY
THAT THE RECENT MORE NORTHERLY JOG WILL LAST...ALTHOUGH THE CURRENT
TREND IS DEFINITELY IN THAT DIRECTION.

THE SYNOPTIC SET UP IS SIMILAR TO LAST SUNDAY WITH A COLD AND DRY
AIR MASS TO THE NORTH AND A LOW PASSING THROUGH THE OHIO VALLEY.
ONCE AGAIN WE EXPECT A SHARP SNOWFALL GRADIENT AS MESOSCALE BANDS
WILL ALIGN EAST TO WEST ACROSS THE SOUTHERN FORECAST AREA IN AREA OF
MID LEVEL F-GEN FORCING. WE BUMPED UP THE POPS AND QPF FOR SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH THE BULK OF THE SNOW FALLING SUNDAY
MORNING. SOME INCH AN HOUR RATES ARE POSSIBLE ACROSS THE FAR SOUTH
SUNDAY MORNING INTO THE AFTERNOON.

THE LOW IS CURRENTLY GATHERING STRENGTH ACROSS THE SOUTHWEST CONUS
AND IS BEING FED BY A DEEP PLUME OF TROPICAL MOISTURE FROM THE
EASTERN PACIFIC. THE LOW WILL ALSO GET GOOD GULF OF MEXICO INFLOW AS
IT MOVES EAST. MEANWHILE...EASTERLY FLOW DEVELOPS AHEAD OF THE
SYSTEM AND A MATURE CYCLONE WITH WARM AND COLD CONVEYOR BELTS TRACKS
ACROSS THE OHIO VALLEY WITH 12Z MODEL GUIDANCE SHOWING ENOUGH QPF TO
COME CLOSE TO WARNING CRITERIA ACROSS THE FAR SOUTH. SNOW TOTALS
WILL PROBABLY END UP 20 TO 1 OR GREATER GIVEN THE COLD AIR IN PLACE
DURING THIS EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 328 PM EST FRI JAN 30 2015

VERY COLD WEATHER WILL CONTINUE MONDAY WITH POTENTIAL FOR SINGLE
DIGIT BELOW TO ABOVE ZERO READINGS EARLY MONDAY MORNING. MAX TEMPS
WILL ONLY REACH THE TEENS MONDAY IN SPITE OF SOME SUN WITH HIGH
PRESSURE IN CONTROL. THE NEXT LOW PRESSURE SYSTEM AND PV ANOMALY
WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY
NIGHT.

THE COLD FRONT SHOULD BE THROUGH OUR AREA BY WEDNESDAY MORNING WITH
ANOTHER INTRUSION OF ARCTIC AIR AND BELOW NORMAL TEMPS FROM
WEDNESDAY NIGHT THROUGH LATE WEEK. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE LATE IN THE WEEK.

OVERALL THOUGH THE SETUP DOES NOT LOOK FAVORABLE FOR LAKE EFFECT
SNOW OF ANY SIGNIFICANCE LATE IN THE WEEK DUE TO THE VERY DRY ARCTIC
AIRMASS AND DRY FCST SOUNDINGS THURSDAY/FRIDAY AS WELL AS VERY LOW
INVERSION HEIGHTS BY THEN. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY
REACH THE TEENS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1158 PM EST FRI JAN 30 2015

AREAS OF MVFR CLOUDS FROM EARLIER HAVE DISSIPATED FOR THE MOST
PART WITH THE EXCEPTION OF THE LAKE MI SHORELINE INCLUDING MKG.
THESE CLOUDS WILL PROBABLY PERSIST MUCH OF TONIGHT AND SATURDAY
AT MKG GIVEN THAT THE LOW LEVEL FLOW IS OUT OF THE SOUTHWEST OFF
LK MI... AND MAY ALSO IMPACT GRR.

OTHERWISE VFR CONDITIONS ARE EXPECTED SOUTH AND EAST OF GRR
TONIGHT AND SATURDAY MORNING WITH SCT-BKN CLOUD BASES MAINLY
ABOVE 8000 FT. SOME LOWER CIGS OF 2500-4000 FT SHOULD SPREAD FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON AS A COLD FRONT
APPROACHES.

FLIGHT CONDITIONS AT ALL THE TERMINALS WILL CONTINUE TO TREND
DOWNWARD AFTER 00Z SUNDAY AS THE FRONTAL BOUNDARY SLIPS SLOWLY
SOUTH THROUGH THE AREA... WITH MVFR BECOMING MORE WIDESPREAD WITH
TIME. THE OUTLOOK BEYOND 06Z SUNDAY IS FOR WIDESPREAD IFR TO
DEVELOP AS SNOW OVERSPREADS THE AREA.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS AROUND
20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...93