FXUS63 KMQT 222039
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
340 PM EST WED JAN 22 2003

12Z RAOBS/LATEST WV LOOP AND RUC ANLSYS SHOW BITTERLY COLD ARCTIC 
AIRMASS OVR SCNTRL CAN ON NRN FLANK OF FAST NW FLOW ALF DOWNSTREAM 
OF RDG ALG THE W COAST. 125KT H3 JET MAX OVR NW PLAINS EMBEDDED 
WITHIN THIS FLOW DRAGGING H5/H7/H85 TEMPS WITHIN CORE OF COLDEST AIR 
AT CYQD -45/-34/-32C SE INTO UPR LKS...AND SFC TEMPS STILL NR -30F 
ARND LK WINNIPEG. DESPITE VERY DRY AIR UPSTREAM OF LK SUP (SFC DWPTS 
AS LO AS -40F) AND SHALLOW NATURE OF COLDEST AIR (INVRN HGT ARND H9 
AT INL) COLDER AIR BLOWING ACRS LK SUP HAS CAUSED NMRS LES BANDS TO 
DVLP OVR AREAS FVRD BY LLVL NW FLOW...AND VSBYS AS LO AS 1/4SM TO 
1SM IN SN/BLSN OVR THE W. COMBINATION OF INCRSG WNDS AHD OF ARCTIC 
SURGE AND TEMPS STILL HOVERING ARND ZERO HAVE CAUSED WND CHILLS AS 
LO AS -25F OVR THE WRN ZNS EVEN EARLY THIS AFTN...SO HAVE STARTED 
GOING ADVYS/WRNGS THAT WERE NOT IN EFFECT UNTIL THIS EVNG THIS AFTN 
OVR THOSE LOCATIONS. MUCH WARMER AIR NOTED AT H85-7 OVR NE CAN AS 
ATLANTIC AIR ADVECTS SW IN NE FLOW ALF ON BACK SIDE OF CLOSED LO OVR 
SE CAN.

NMRS FCST CONCERNS IN THE SHORT TERM INCLUDING LES/BLSN/WND CHILLS 
AS WELL AS GOING HEADLINES.

AS H3 JET MAX IN NW PLAINS AND ASSOCIATED H5 SHRTWV OVR SCNTRL CAN 
SLIDE SE TNGT...12Z MODELS SHOW CORE OF COLDEST AIR SLIPPING SE ACRS 
UPR LKS TNGT. ALL MODELS SHOW PERSISTENCE OF TIGHT PRES GRADIENT/ 
NWLY LLVL FLOW OVR ENTIRE AREA TNGT...WITH ETA FCST SDNGS SHOWING 25 
TO 35KT WNDS WITHIN MIXED LYR ELEVATED BY WRMG FM LK SUP (INVRN HGT 
UP TO 5K FT DOWNWND OF LK). GFS SHOWS LLVL WND FIELD SHIFTING MORE 
NNW TNGT WHILE ETA INDICATES NR SFC FLOW WL REMAIN MORE NW. GIVEN 
DIGGING OF SHRTWV TO THE SW AND TREND OF ETA H925 WNDS TO VEER 
SIMILAR TO GFS SFC FLOW...SUSPECT GFS WNDS MORE APPROPRIATE. WND 
DIRECTION IMPORTANT BECAUSE FLOW WL DICTATE LK MODERATION OF TEMP 
(I.E. WIND CHILL) AS WELL AS LES POTENTIAL. XPCTD LLVL FLOW WL 
SUPPORT LOWEST MINS OVR GOGEBIC COUNTY PER GFS/ETA H100-85 THKNS 
FILED WITH GREATEST LK SUP MODERATION E OF MQT. COMPARISON OF FCST 
H100-85 THKNS AND MINS UPSTREAM WOULD SUG LO TEMP DOWN TO -10F AT 
IWD (WITH TEMP STEADY AFTR 06Z AS H100-85 THKNS MODIFIES WITH 
ARRIVAL OF ATLANTIC AIR/MORE NE FLOW WELL ALF LATE TNGT). FCST THKNS 
OVR THE E WOULD SUPPORT LOWS 0 TO -3F. SUSTAINED WND SPEED OF 20-25 
MPH/10 MPH NECESSARY TO ACHIEVE -25F WND CHILL FOR 0 TO -3F/-10F AIR 
TEMP...SO WND CHILLS E OF MQT-MNM LIKELY TO REACH ADVY CRITERIA ONLY 
INTERMITTENTLY WHILE ADVY CONDITIONS TO W WL PREDOMINATE. THUS GOING 
WND CHILL FCST ON TRACK. LES CHART FOR XPCTD CONDITIONS WOULD SUG 4" 
SN/6 HRS...BUT VERY DRY/COLD AIR AND OBSVD SNFALL DURG THIS COLD 
OUTBREAK WOULD SUG NO MORE THAN 2"/6 HRS. HOWEVER...WL GO UP TO 
3-4"/6 HRS OVR THE ERN ZNS IN LONGER FETCH ACRS WATER AND FCST 
PASSAGE OF GREATER H85-5 QVECTOR CNVGC/DPVA/H85-5 RH ASSOCIATED WITH 
DIGGING SHRTWV. SO GOING FCST UP TO 6-8 INCHES OVR THE ERN SN BELTS 
APPEARS ON TRACK. HAVE OPTED TO GO UP TO 5 INCHES OVR SN BELTS IN 
ONTONAGON/GOGEBIC COUNTIES TO ACCOUNT FOR SOME ENHANCEMENT FM XPCTD 
LLVL CNVGC BTWN VEERING LLVL FLOW AND MORE WLY LAND BREEZE THAT 
MIGHT TRY TO HOLD ON LONGER NR IWD THAN FCST BY GFS (MORE IN LINE 
WITH ETA FCST). BUT TENDENCY FOR STRENGTH OF LLVL FLOW TO OVERWHELM 
LAND BREEZE COMPONENT CAN JUSTIFY NO MORE ENHANCEMENT. KEWEENAW/CMX/ 
BARAGA/MQT ZNS SHUD BE SHIELDED WITH XPCTD FLOW...BUT ERN MQT COUNTY 
MAY SEE A BIT MORE LES LATER IF FLOW VEERS TO 340. GOING HEADLINES 
APPEAR APPROPRIATE. EVEN THOUGH SN AMTS MAY NOT JUSTIFY WRNG 
CRITERIA IN GOGEBIC/ONTONAGON AND ALGER/LUCE/NRN SCHOOLCRAFT... 
COMBINATION OF SN/BLSN/WND CHILLS JUSTIFY WRNG THESE AREAS.

ETA REMAINS MORE AGGRESSIVE THAN GFS IN LWRG INVRN HGT ON THU MRNG 
AS H5 HGTS RISE IN ADVANCE OF UPR RDGING IN WAKE OF ARCTIC VORTEX 
SLIPPING S THRU THE GRT LKS. SINCE GFS HAS BETTER HANDLE ON H85 TEMP 
(I.E. INVRN HGT) THAN ETA OVR NE CAN AND ETA HAS TRENDED SLOWER ON 
CRASHING INVRN HGT...WL TREND TOWARD SLOWER GFS SOLN. ALTHOUGH LWRG 
INVRN/INCRSG H85 TEMPS WOULD SUG A DIMINISHING TREND IN LES...INCRSG 
TEMPS/LESS INHIBITIVE SN GROWTH DYNAMICS MIGHT OFFSET XPCTD TREND TO 
A CERTAIN EXTENT. SINCE PRES GRADIENT IS FCST TO REMAIN SHARP ACRS 
THE ENTIRE CWA IN THE MRNG...WL MAINTAIN GOING HEADLINES INTO THU 
MRNG. HAVE OPTED TO CONT WINTER STORM WRNG INTO THE AFTN OVR THE E 
BECAUSE DEEPER MSTR/LONGER FETCH FCST TO LINGER THERE UNTIL THE AFTN 
TO SUPPORT MORE SN...AND GFS/ETA ALSO SHOW HIER WNDS LINGERING 
LONGER THERE. ADVCTN OF ATLANTIC AIR ALF WL MODERATE LLVL TEMPS ON 
THU...BUT CHILL IN PLACE NOW JUSTIFIES FOLLOWING LWR GFS/ETA MOS 
FCST FOR HI TEMPS. CONSIDERING TREND TOWARD DEEPER MSTR REMAINING 
LONGER AND LINGERING H85-5 QECTOR CNVGC THRU NOON...HAVE UPPED FCST 
SN AMTS IN THE E TO 6 INCHES. NO MORE THAN 3 INCHES ACRS THE W WITH 
FASTER ARRIVAL OF DRIER AIR.

ARRIVAL OF UPR RDGING/H85-5 QVECTOR DVGC AND MORE ACYC SFC FLOW/DRY 
AIR SHOULD SUPPRESS LINGERING LES THU NGT...ESPECIALLY OVR THE 
WCNTRL. HOWEVER...ETA/GFS POINT TOWARD CONTG LLVL CNVGC OVR THE ERN 
ZNS (ALBEIT WITH LIGHTER WNDS) AS NW LLVL FLOW IN ADVANCE OF SFC RDG 
MEETS NE LAND BREEZE OFF NRBY ONTARIO. VORTEX MAY SET UP OVR SE LK 
SUP IN CNVGC BTWN THESE TWO RELATIVELY LGT AIRSTREAMS. BUT LWRG 
INVRN HGTS (ETA SHOWS INVRN HGT DOWN TO 2K FT WITH LESS DISCREPANCY 
BTWN GFS/ETA ON H85 TEMP) SUGS THERE WL BE NO MORE THAN A FEW INCHES 
ADDITIONAL ACCUM. VORTEX MAY ENHANCE LAND BREEZE OVR WCNTRL. 
COMBINATION OF LGT WLY FLOW AND CLRG SKIES SHUD ALLOW MINS TO FALL 
TO LWR AVN/ETA MOS GUIDANCE OVR INTERIOR AREAS.

MODELS HAVE TRENDED FASTER WITH SHRTWV FCST TO PASS ESE THRU ONTARIO 
ON FRI. SOME WEAK WAD/ISENTROPIC LIFT FCST TO BEIN DURG THE AFTN... 
BUT LLVLS ARE SO DRY PER ETA FCST SDNGS TO XPCT MUCH PCPN. ALSO... 
SHRTWV/ASSOCIATED H85-5 QVECTOR CNVGC TRACKS N OF CWA...WHICH LIES 
IN UNFVRBL RIGHT EXIT OF SUPPORTING H3 JET MAX. AFTR LINGERING SHSN 
OVR THE ERN ZNS DIMINISH IN THE MRNG UNDER CONTD MID LVL HGT 
RISES...WL JUST INDICATE INCRSG HI/MID CLD WITH NO PCPN. APRCH OF 
ASSOCIATED SFC TROF AND HIER H85-5 QVECTOR CNVGC/RH MAY PROVIDE 
BETTER FOCUS FOR PCPN THEN. GFS INDICATES LLVL WND FIELD BE TOO W 
FOR ANY LK ENHANCEMENT OFF LK MI IN ADVANCE OF FNT. COLD FNT PUSHES 
THRU CWA SAT AFTN...SO PTCHY LGT SN WL EVOLVE INTO PURE LES AS H85 
THERMAL TROF WITH TEMPS APRCHG -25C APRCHES DURG AFTN. TEMPS WL 
MODERATE IN ADVANCE OF BNDRY ON FRI...THEN NOT FALL TOO FAR FRI NGT 
WITH FAIRLY TIGHT PRES GRADIENT IN PLACE. MOS FCST TEMPS IN DECENT 
AGREEMENT AND SEEM APPROPRIATE.

00Z/06Z OPERATIONAL EXTENDED MODELS/ENSEMBLES POINT TOWARD A MORE 
VIGOROUS ARCTIC INTRUSION SAT NGT FOLLOWING THE SHRTWV RESPONSIBLE 
FOR SN CHCS FRI NGT/SAT. WL GO LIKELY SHSN FOR THE SN BELTS FVRD 
WITH NW FLOW SAT NGT INTO SUN (CHC SHSN/FLURRIES ELSEWHERE) AND LWR 
GOING FCST TEMPS TO REFLECT TREND TOWARD H85 TEMPS DROPPING TOWARD 
-25C AGAIN (VS -20C FCST YDAY). 12Z MODELS CONFIRM THIS TREND. LES 
SHUD DIMINISH LATER ON SUN AS ARCTIC HI PRES BLDS OVHD. VERY GOOD 
AGREEMENT INDICATING VIGOROUS WAD PATTERN SETTING UP ON MON AS 
ARCTIC HI PRES CENTER SHIFTS TO E AND INCRSGLY ZONAL FLOW ALF CAUSES 
STEEP PRES FALLS ACRS SW CAN/NRN PLAINS. GOING FCST CHC SN WITH 
EASING CHILL ON MON STILL ON TARGET. THEN ZONAL FLOW WITH ABV NORMAL 
H5 HGTS TO PREDOMINATE STARTING TUE. XCPT ONLY SHALLOW COLD AIR (NO 
LES) TO FILL IN BEHIND LO PRES/CHC SN ON TUE...WITH SOME SUNSHINE 
ALLOWING WELL ABV NORMAL TEMPS ON WED.

COORDINATED WITH DLH/APX/GRB.

.MQT...WINTER STORM WARNING INTO THU MORNING MIZ002-009.   
       WINTER STORM WARNING INTO THU AFTN 006-007-085. 
       WINTER WEATHER ADVY INTO THU MORNING MIZ001-003.
       WIND CHILL ADVY INTO THU MORNING MIZ004-005-010-011-012-084.  
       HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. 

KC