Area forecast discussion
National Weather Service Duluth Minnesota
401 am CDT Tuesday may 21 2013
Short term...County Warning Area remains under large anomalous circulation that has
been trapped over ctrl Continental U.S. Last few days. Another band of rain
is rotating around the system and pushing into the southern County Warning Area. Will
let flash Flood Advisory continue through morning although biggest threat appears
to be across southern County Warning Area where main forcing should occur.
Today...area of rain/thunder currently over southern County Warning Area is aligned with
sharpening 850 mb thetae axis as it wraps into middle level low. This
feature is forecast to stretch east to west across southern County Warning Area today.
Limited convective potential as cloud canopy and deeply saturated
column make for some Low Cape values sfc/aloft. Most favorable
combo of instability/sufficient deep layer shear is over southeastern wisc
zones in the afternoon. Area of frontogenesis that has been fairly
persistent over northern Minnesota zones is forecast to weaken so have tapered probability of precipitation
through the afternoon hours. Another chilly day near Lake Superior as
strong onshore flow/clouds/precip limits temperature rise.
Tonight...deep layer drying should begin to push farther south into
Minnesota zones. Best thermodynamics...850 mb thetae axis...shifts south of
region by 12z. Brd lakes region may remain underneath middle level
cyclonic circulation and collapsing low level thetae ridge long
enough to keep quantitative precipitation forecast a bit higher than remainder of County Warning Area.
Tomorrow...middle level low slides southeast of County Warning Area and ridging builds
aloft. Surface high increases and precipitable waters drop considerably during the
day. Should be enough sunshine to make northwestern part of County Warning Area the warmest
with lowest readings occurring in southeastern County Warning Area.
Long term...Wednesday night through Tuesday.
The massive low pressure system that has affected the region the
past several days will finally pull out of the Northland completely
Wednesday night...as dry high pressure builds in from the north. On
Thursday we could see very low relative humidity values...after
seeing high relative humidity for quite some time. The dry air from
the Hudson Bay high will likely last into Friday night before some
precipitation possibly makes it into at least the SW half of the
region. Do think it is possible that the dry high pressure system
could hold off the precipitation throughout the weekend and maybe
even into the first part of the upcoming work week. The European model (ecmwf) is
most dry across the area...with the GFS and Gem bringing some
precipitation into the County Warning Area. High temperatures will largely be in the
60s for the entire extended with cooler temperatures near Lake Superior.
Aviation...06z taf issuance...
IFR ceilings and MVFR visibilities in scattered rain showers and patchy fog
tonight and most of Tuesday...along with a few isolated storms over hyr
early Tuesday morning. Winds will continue to be gusty from the
NE...with the strongest winds around dlh. Could see another round of
afternoon showers and storms move in from the south during the
afternoon on Tuesday...with the southern terminals having the best chance
of being impacted...mainly hyr once again.
Point temps/pops...
dlh 49 41 57 41 / 70 60 50 10
inl 52 40 66 39 / 60 30 10 0
brd 57 45 61 44 / 70 60 50 10
hyr 64 44 56 42 / 70 60 60 20
asx 49 40 52 40 / 80 50 60 10
&&
Dlh watches/warnings/advisories...
Minnesota...Flash Flood Watch until 10 am CDT this morning for mnz010>012-
018>021-025-026-033>038.
WI...Flash Flood Watch until 10 am CDT this morning for wiz001>004-
006>009.
Ls...dense fog advisory until 11 am CDT this morning for lsz121-
140>148.
Small Craft Advisory until 11 am CDT Wednesday for lsz121-
140>148.
&&
$$
Short term...Cannon
long term....dap
