Area forecast discussion
National Weather Service Grand Forks ND
942 am CDT Thursday may 23 2013
Update...
issued at 935 am CDT Thursday may 23 2013
No changes necessary for this update period. Skies to remain sky clear
today and temperatures in line with forecast rise.
Update issued at 634 am CDT Thursday may 23 2013
Made a few tweaks to hourly temperatures as they are running a bit
cooler than what we had going. Otherwise no changes needed as
conditions remain pretty quiet.
&&
Short term...(today through friday)
issued at 342 am CDT Thursday may 23 2013
Temperatures and timing of precipitation moving in Friday will be the
primary concerns for the period.
Quiet conditions will continue for the next day or so as upper
ridging builds into the region between systems. Surface high pressure
will continue to nose down into the upper Midwest from Canada.
Northeasterly winds will bring some drier air into the area this
morning but then gradually shift around to the southeast later
today. There will be some cooler 850mb temperatures moving in but with
plenty of sun we should still get well into the 60s in most areas
for highs.
Southeasterly winds will increase a bit tonight as surface low
pressure deepens over eastern Montana. West will see the biggest impact
from mixing while the eastern counties will still be drier with
light winds and many locations will drop below 40 degrees. The
southeasterly winds will continue into Friday and highs should be
mainly in the 60s.
By Friday afternoon the surface trough will move into western ND.
Models all break out some precipitation along a frontal boundary/wind
shift Friday afternoon. Continued to keep chance probability of precipitation going for
the western counties Friday afternoon. Not much surface based cape to
work with but showalters still get close to zero so kept showers
with isolated thunderstorms.
Long term...(friday night through wednesday)
issued at 342 am CDT Thursday may 23 2013
Friday night...precipitation will continue to move into the eastern County Warning Area
but the main frontal boundary will begin to wash out. Continued to
keep high chance probability of precipitation going but with the main upper shortwave
still well off to the north think that most activity will be
pretty scattered so will not put in any likelies for the time
being. Think there should be a break in the precipitation at least over
the western part of the County Warning Area Saturday morning before a weak
shortwave comes over the top of the ridge and sets off some
activity Saturday afternoon and evening. NAM has hardly anything
in our western counties but the global models are a bit more wet.
Will continue to keep around 30 probability of precipitation going for Saturday afternoon
and night.
Sunday-Wednesday...quite a bit of uncertainty exists throughout this
period. 00z models indicate the upper ridge axis will begin to break
down and shift eastward during the period...with southwest flow
aloft developing. However...compared with the GFS...the European model (ecmwf)/Gem
maintain a more amplified ridge over the region into early next
week. With slower moisture return...this would significantly lessen
precipitation chances through Memorial Day. Given the overall
uncertainty...will keep some chance probability of precipitation...highest west...through
Monday...although quite a few dry hours are expected. After
Monday...model differences become magnified...with the European model (ecmwf)
continuing to be much less progressive than the GFS with the
synoptic pattern. The European model (ecmwf) does begin to shift the
moisture/instability axis eastward into the region with persistent
low-level southerly flow ahead of the upper trough. Thus...precipitation
chances may increase towards mid-week...although run-to-run
consistency among models has been poor.
With gradually rising thicknesses through the period...high temperatures
are expected to rise from the 60s to low 70s for the latter half of
the Memorial Day weekend into the middle 70s by the middle of next
week...with lows mainly in the 50s.
&&
Aviation...(for the 12z tafs through 12z Friday morning)
issued at 634 am CDT Thursday may 23 2013
VFR conditions will continue as cirrus moves over the area.
Northeasterly winds around 10 kts will become southeasterly by
evening.
&&
Hydrology...
issued at 342 am CDT Thursday may 22 2013
River flood warnings remain in effect at Walhalla and Neche along
the Pembina river...with Walhalla having crested and falling...and
Neche now beginning to fall slowly.
The Park River at Grafton appears to be near its crest this morning
a bit under its record of 16.5 feet.
There are also a few river points within the area that are expected
to reach minor flood stage.
Areal flood warnings remain in effect for Pembina...eastern
Cavalier...and Walsh counties. The main surge of water is now into
central Pembina and Walsh counties...and will continue to move
toward the Red River. Water levels across this area should gradually
decrease over the next few days with little additional rainfall
anticipated.
A Flash Flood Watch remains in effect through Friday afternoon for
areas downstream of the Renwick dam on The Tongue river. Water
remains very high at the dam site and is being held back by a
constructed earthen levee on top of the dam structure. Also...
officials are continuing to monitor several retention dams to the
west of Renwick dam. At this time...officials note the temporary
levee on top of the Renwick dam appears to be stable and will be
continually monitored. Lake Renwick has slowly receded over the past
few hours. Water has stopped flowing over the emergency spillways at
most of the retention dams west of the Renwick dam. However...the
threat remains and failure would mean major flooding would be
imminent for the cities of Akra...Cavalier...and Bathgate.
&&
Fgf watches/warnings/advisories...
ND...Flash Flood Watch through Friday afternoon for ndz008.
Minnesota...none.
&&
$$
Update...voelker
short term...Jr
long term...Jr/makowski
aviation...Jr
hydrology...makowski
