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Office: MKX

FXUS63 KMKX 181915

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
215 PM CDT Sun Mar 18 2018


Monday through Thursday - Confidence...Medium to High
Looks like a cool and dry period. Low pressure will be passing
well to our south and southeast tonight into Tuesday which will
reinforce the cooler regime and tighten up the pressure gradient.
Surface ridging takes hold for Wednesday and Thursday with more
quiet and cool conditions.

Friday and Saturday - Confidence...Low to Medium
Models continue to be in decent agreement on bringing the next
weather maker of concern into the area this period. The ECMWF is
considerably slower than the GFS. At this point a mix or a brief
period of rain would be possible at the outset with the
predominant precip type looking more like snow. Potential is still
there for several inches of snow so have maintained a highlight
of this in the HWO.

Saturday night and Sunday - Confidence...Medium
Should have a break between systems, with the ECMWF implying this
would last throughout the day on Sunday. Meanwhile the GFS brings
another system in which could arrive as soon as Sunday afternoon
with potential there for snow or a mix with this one as well.


.AVIATION(18Z TAFS)...VFR mostly skc this period. Northeast winds
will increase tonight into Monday as pressure gradient tightens up
between Canadian high pressure and low pressure moving well to
our south.


.MARINE...Small Craft Advisory starts later tonight and goes
through Tuesday night. This is due to the ramping up of an onshore
component that is likely to generate high wave action. Low
pressure passing to our south will help to tighten up the pressure
gradient and the subsequent uptick in the northeast winds.


LM...Small Craft Advisory from 4 AM Monday to 7 AM CDT Wednesday for


Tonight/Monday and Aviation/Marine...Collar
Monday Night through Sunday...Collar

Office: ARX FXUS63 KARX 182008 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 308 PM CDT Sun Mar 18 2018 .SHORT TERM...(This evening through Monday) Issued at 308 PM CDT Sun Mar 18 2018 Upper-level ridging and surface high pressure were in place over the Upper Mississippi River Valley this afternoon, with an upper-level longwave trough over the Rockies. Low clouds over northern Iowa into southern Minnesota have been more persistent than expected, keeping temperatures a bit cooler in these areas. The western longwave trough is forecast to break down tonight, with a southern stream stacked-low approaching the Ozarks Monday morning and a northern stream weaker disturbance/surface trough sliding through the Dakotas. Strong surface high pressure over northern Manitoba/Ontario will help steer these systems to the south and east, keeping precipitation away from our area through Monday. .LONG TERM...(Monday night through Sunday) Issued at 308 PM CDT Sun Mar 18 2018 Main forecast concerns in the long term are on chances for light rain and snow Monday night into Tuesday. Focus then turns to the continued dry weather through Thursday then onto the potential rain and accumulating snow Friday into Saturday. A trough edges east into the Upper Mississippi River Valley from the northern Plains Monday night into Tuesday morning. Meanwhile, surface high pressure attempts to hold strong across the western Great Lakes, centered near over Hudson Bay. This will result in a persistent dry east/northeast flow. The trough will be slamming into this drier air and it appears any precipitation will struggle to get east of the Mississippi River. Will continue low chances for rain and snow across southeast Minnesota, northeast Iowa, and west central Wisconsin on Tuesday. Any snow or rainfall amounts will be on the light side thanks to that feed of dry air into the region. The Hudson Bay surface high looks to be the dominant weather feature from Tuesday night through Thursday providing dry weather across the region. Thursday looks to be the warmest day with highs climbing into the mid 40s at many locations. The good news is winds look to remain on the lighter side across the area limiting any fire weather concerns. Afternoon relative humidity values will need to be watched closely. A baroclinic zone then sets up over the area late Thursday through Saturday as a trough moves across the central conus and low pressure deepens over the Central Plains into the mid Mississippi River Valley. Precipitation is looking very likely across the area in the Friday through Saturday timeframe. Depending on the storm track, a band of significant snowfall is possible. There is a lot of uncertainty with the storm track and resulting thermal profiles so it's difficult to nail down where snow would fall at this point. This system will have to be watched very closely this week. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1234 PM CDT Sun Mar 18 2018 VFR conditions are expected at both TAF sites through this forecast period. Cloud cover will increase at KRST by mid- afternoon. However, expect ceilings to remain above 3 kft. Winds will remain light and variable until becoming east-northeast around 10 kt late Monday morning. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...MH LONG TERM...Wetenkamp AVIATION...Hollan
Office: GRB FXUS63 KGRB 181938 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 238 PM CDT Sun Mar 18 2018 Forecast discussion for routine afternoon forecast issuance .SYNOPSIS... Issued at 232 PM CDT Sun Mar 18 2018 Quiet weather will continue for at least several more days. The large scale flow across North America will remain split throughout the forecast period. For the most part, the area is likely to remain positioned between the main branches of the flow. A series of anticyclones passing through the Hudson Bay region will dominate the weather across the forecast area, driving cool dry Canadian air into the region. The warm weather of today is departing, with temperatures expected to return to near or a little below seasonal normals for the upcoming work week. Precipitation chances will be minimal until at least the end of the work week and the upcoming weekend, when a southern stream cyclone heads east from the Plains. Even then, it's quite possible that system will pass by to the south. && .SHORT TERM...Tonight and Monday Issued at 232 PM CDT Sun Mar 18 2018 Another mild day with very low afternoon relative humidity readings. Temperatures were in the middle 40s to middle 50s as of mid afternoon. Relative humidity readings away from the lake were in the 15 to 30 percent range. For the remainder of the afternoon and this evening, a backdoor cold front is expected to drop southwestward across the area bringing an end to the mild weather. Skies are expected to become mostly cloudy across the entire region tonight with decreasing cloudiness late Monday morning into Monday afternoon. Took blend of the better performing guidance for lows tonight and highs on Monday. .LONG TERM...Monday Night Through Sunday Issued at 232 PM CDT Sun Mar 18 2018 Colder air associated with the Hudson Bay high will continue to surge into the area Monday night. Blustery conditions are expected as well as the pressure gradient tightens between the anticyclone building southeast across Canada and a cyclone tracking through the Ohio Valley. The air flowing across the Great Lakes could be cold enough to result in flurries off Lake Superior and Lake Michigan, which may linger into Tuesday. Most of the precipitation from a weak northern stream shortwave breaking away and merging into the southern stream mid-week still appears likely to stay mainly west of the area, though it's possible some flurries will reach the area. The medium range guidance continues to suggest a strong southern stream cyclone heading east across the Plains late in the week and next weekend will affect the area. The GFS and Canadian models have been pretty consistent with the track, while the ECMWF has been oscillating between a similar track to the other models and one farther south. Given that all but one of the significant cyclones crossing the region in the past 3 weeks have passed the area by to the south, it seems most likely that the more southerly ECMWF runs are going to end up being the most accurate. Even if a more northerly track materializes, the system will have to contend with very dry air feeding into the area from the Hudson Bay high. Given the degree of uncertainty out toward the end of the forecast period, stuck with the standard forecast initialization grids and maintained a mention of the system as in the previous HWO. && .AVIATION...for 18Z TAF Issuance Issued at 1136 AM CDT Sun Mar 18 2018 VFR conditions will continue into this evening as mid and high clouds move into the area. Later this evening into Monday morning, MVFR CIGS are expected to develop behind a cold front. Some areas of IFR conditions are across portions of north-central Wisconsin, including KRHI. MVFR cigs will continue through much of Monday morning and possibly into Monday afternoon before CIGS improve. Otherwise, a backdoor cold front is expected to push southwestward across the area late this afternoon or this evening. The front should reach KGRB/KMTW/KATW between 21z and 23z, KRHI around 02z and KAUW/KCWA around 03z. Not your typical Wisconsin cold front as winds behind the front should turn to the northeast or east. Gusty winds are expected in the 15 to 20 knot range, except at KGRB/KATW where funneling down the bay of Green Bay and the Fox River could push gusts over 20 knots at KGRB/KATW. Northeast winds will stick around for the next few days. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS.......Skowronski SHORT TERM.....Eckberg LONG TERM......Skowronski AVIATION.......Eckberg