Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/23/19
Area Forecast Discussion
National Weather Service Cheyenne WY
814 PM MDT Mon Apr 22 2019
.UPDATE...
Issued at 806 PM MDT Mon Apr 22 2019
Dense Fog Advisory has been allowed to expire. A few patches of
dense fog remain, especially near the I-80 Summit, however
coverage has decreased and should remain localized through tonight.
Will continue to monitor webcams in the case dense fog becomes
more widespread.
UPDATE Issued at 523 PM MDT Mon Apr 22 2019
Webcams near the I-80 Summit still show dense fog in spots with
surface easterlies creating upslope flow. Areas of dense fog will
continue early this evening before winds begin to turn more
southerly. Therefore extended the Dense Fog Advisory through 8 PM
MDT.
&&
.SHORT TERM...(Late this afternoon - Tuesday night)
Issued at 315 PM MDT Mon Apr 22 2019
The afternoon WV/IR imagery showed a progressive northern stream
flow aloft with a slower southern stream marked by a southward
drifting mid/upper low over southeast CA/western AZ. Surface
analysis showed the remnants of boundary that moved through the
CWA yesterday was located from south central WY into western CO.
Scattered showers and a few weak tstorms were developing over
southern Carbon County and will spread to the north and east
through late afternoon. Stubborn low stratus and fog formed this
morning over portions of southeast WY. The fog has been dense from
the I-80 Summit to Vedauwoo. A Dense Fog Advisory is in effect
for these areas until 6 PM, however the HRRR prolongs the fog and
low clouds through late tonight. Added fog for the I-80 corridor
from Arlington to Cheyenne and Pine Bluffs.
The short range models/ensembles are in good agreement with the
large scale flow aloft. The southern stream low tracks southeast
into northern Mexico, with ridging aloft becoming the dominant
feature for the CWA. This pattern will promote milder and drier
weather Tuesday and Tuesday night.
.LONG TERM...(Wednesday - Monday)
Issued at 302 AM MDT Mon Apr 22 2019
A muddled extended forecast period with the models showing broad &
flat upper-level ridging evolving across the western/central CONUS
during the mid/late week time frame. In general, this should yield
warmer temperatures for the most part. However, not necessarily on
the dry side as the area is likely to be on the northern fringe of
the aforementioned ridge. Quasi-zonal flow aloft prevails along w/
numerous waves embedded within the general flow pattern. A frontal
boundary appears to slip into our northern & eastern zones by late
Wednesday, possibly supporting shower/thunderstorm chances. Models
suggest quite a few additional weak ripples through Saturday. This
may support isolated showers somewhere in our CWA on a daily basis
through the period. Fortunately, no major storms appear likely for
the foreseeable future.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 451 PM MDT Mon Apr 22 2019
Airport of concern this evening is KCYS. We did break the IFR
conditions late afternoon that brought them to MVFR. Concern is
that the lower conditions could lower back down after sunset.
Nothing indicating this happening...but winds are not changing
from what we had all day. Even more southeasterly directions would
be favorable for lower ceilings. For now...will monitor WYDOT
Webcams west of Cheyenne. If they show a lowering of ceilings over
time...will likely need to lower to IFR through and amendment.
Improving conditions elsewhere.
&&
.FIRE WEATHER...
Issued at 302 AM MDT Mon Apr 22 2019
No fire weather concerns w/ much cooler temperatures over the next
24-48 hours with recent precipitation across most districts. Highs
will trend warmer from Tuesday onward, but RH values should remain
well outside of critical thresholds in the afternoons w/ excellent
recoveries overnight.
&&
.HYDROLOGY...
Issued at 235 PM MDT Mon Apr 22 2019
Milder temperatures are forecast from Tuesday through Sunday. There
will be slight chances of mainly afternoon and evening showers and
thunderstorms Wednesday through Monday. Heavy precipitation is not
expected. High temperatures above 8500 ft will result in some snow
melt runoff, mitigated by freezing low temperatures. There is the
possibility of rain on snow from mid-week onward, which will cause
rivers and streams to run high for the next several days.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...MB
SHORT TERM...MJ
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...CLH
HYDROLOGY...MAJ
Area Forecast Discussion
National Weather Service Gray ME
1029 PM EDT Mon Apr 22 2019
.SYNOPSIS...
Low pressure south of New England will move northward tonight to
a position just south of Nova Scotia Tuesday evening. This low
will bring the region more rainfall, the heaviest of which will
be on the coastal plain. Another low pressure system will
approach from the west Tuesday night bringing more rain to the
region Tuesday night into Wednesday. More rain is expected by
the end of the week with another low pressure system.
Temperatures will be colder than normal to near normal through
much of the forecast period.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Update...Most notable at this hour is an upper level feature
rotating onshore near Cape Ann. Almost like a MCV...this
cyclonic swirl is very evident on IR satellite imagery. What it
is doing is peeling off a piece of higher PWAT air...near 1
inch...from the main atmospheric river well offshore. This is
also occurring in the left exit region of the H5 jet and in a
region of 300 mb jet divergence. This is supporting the lift to
take advantage of the high PWATs and produce occasionally heavy
rainfall in the SErn NH and SWrn ME vicinity. Dual-pol DPR is
suggesting rates briefly nearing 2 inches per hour are possible
in the heaviest bands. I have increased QPF amounts slightly and
expanded the area of heavy rainfall wording in the grids.
Hi-res guidance is highlighting the Seacoast region as most
likely to see heavy rainfall...in excess of 1 inch overnight.
HREF probability matched mean QPF is showing around 1.5 with
locally higher amounts approaching 2 inches for this region as
well. This is the same region the HRRR and HRRRE is highlighting
as well. So I feel comfortable with heavy rain wording there. 1
hr QPF forecasts also show the window from roughly now through
2 AM to be most likely window for heavy rainfall. Hourly rates
pushing a half inch could lead to some standing water on
roadways and urban/small stream type flooding given the wet
ground primed for runoff.
Previous discussion...Stacked low pressure south of New England
this Monday afternoon will slowly move northeastward to a
position in the Gulf of Maine Tuesday. Rain is already spreading
northward into southern NH as of this writing and will continue
to spread northward this evening.
A period of moderate midlevel frontogenesis this evening and
overnight will move northward over the coastal plain aiding in
moderate to locally heavy periods of rain. While the main plume
of high PWATS will be located offshore, CCB will contain PWATS
over an inch over portion of Maine and New Hampshire, possibly
aiding in total rainfall amounts between 1-1.5" in spots. The
heaviest rainfall is expected on the coastal plain, with the
Seacoast of NH and York County ME the best candidates to see
those higher amounts.
At this time, we are expecting the heaviest QPF axis to stay
south and east of the mountains so any river rises should not be
overly troublesome. Will continue to watch trends, however. In
any case, urban and small stream flooding will be a possibility
overnight on the coastal plain. Thunder not out of the question
on the immediate coast tonight, but probabilities too low at
this time to include in forecast.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Low pressure will continue to move northeastward through the
Gulf of Maine on Tuesday, with the rain moving out of southern
New Hampshire late tonight or early Tuesday morning, and most of
our Maine zones by midday. However, a quick-moving short wave
trough will approach from the west late in the day bringing more
showers to the region Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Upper level low moving through the Great Lakes will
generate some residual showers Wednesday morning. Upslope conditions
in the mountains will keep showery precipitation in place longer
there. Upper level flow turns more westerly behind the system on
Thursday. This will allow temperatures to warm a little bit from
Wednesday and should result in a dry day as well... probably the
nicest day of the work week. Low pressure begins to develop over the
mid Atlantic states Friday morning, with precipitation moving into
the forecast area by midday. The system turns into a bit of a
coastal low as it deepens over the Gulf of Maine. Precipitation
Friday afternoon and evening could be fairly heavy in places. This
system pulls off into the Canadian maritimes rather quickly, with
northwest flow returning for Saturday. It looks like there will
probably be a decent pressure gradient behind the system on
Saturday, so would expect gusty winds. The dry weather on Saturday
will be short lived as another low pressure system moving through
the Great Lakes will approach the region Saturday night. This looks
like a very fast moving system and will likely produce at least some
precipitation.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Short Term...MVFR to higher-end IFR expected for most terminals
tonight in low clouds and rain. However, LIFR conditions will be
possible on the immediate coast. Some improvement is foreseen
for Tuesday, especially midday onward. However, lower conditions
will re-enter the picture Tuesday night with more rain.
Long Term...Expect VFR conditions on Wednesday and Thursday,
deteriorating to IFR/LIFR conditions on Friday as a coastal low
generates some widespread rain.
&&
.MARINE...
Short Term...Northeasterly SCA-level winds are expected on the
ocean waters tonight through Tuesday as low pressure gradually
passes off to our east. Seas will build accordingly as well.
Long Term...May need an SCA for winds on Wednesday in the
wake of low pressure moving through the area. A stronger system
will affect the waters on Friday, with SCA criteria being met
or possibly even reaching Gales.
&&
.HYDROLOGY...
Rivers will remain high through the week with additional
snowmelt and several chances for rain. We will have to monitor
this situation closely, as it would not take too much rain to
cause the rivers to rise again, especially tonight and Tuesday.
At this time, highest rainfall amounts are likely to be on the
coastal plain tonight. However, up to a half inch will be
possible in some basins in the foothills which could result in
some modest additional rises. On the coastal plain, some small
stream, urban and poor drainage flooding will be possible. Will
also have to watch for a potentially significant rainfall Fri-
Sat as some deterministic guidance and ensemble members suggest.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ150-152-154.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Marquette MI
636 PM EDT Mon Apr 22 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 428 PM EDT MON APR 22 2019
WV imagery and RAP analysis indicated a mid/upper level trough from
southern Manitoba through the upper Mississippi Valley. A prominent
shortwave trough over northeast IA was lifting slowly to the
northeast. At the surface, low pressure was located over northeast
IA with a warm front to the northeast through central WI. Strong
800-600 mb fgen and associated upper level div with the right
entrance of the 250-300 mb jet through nrn Ontario supported an
area of light to moderate rain from western WI into wrn Upper
Michigan.
Late this afternoon into tonight, although the stronger fgen over
the west is expected to lift off to the northeast and weaken this
evening, increasing 700-300 qvector conv ahead of the shrtwv should
still maintain the area of rain as it slides to the east through
Upper Michigan. Upslope northeast flow into north central Upper
Michigan should also help to boost rainfall amounts. With additional
QPF in the 0.35-0.75 inch range along with continued snowmelt
runoff, the Flood Watch and ESF highlighting lingering flood
risks were maintained. Locally dense fog in upslope flow locations
north should also diminish as the rain moves in this evening and
drier air with greater mixing takes over late.
Tuesday, mid level and sfc ridging will move in with clouds clearing
from west to east in the morning but may linger a bit longer north
central where upslope flow continues. Even with afternoon sunshine,
northerly winds will keep highs in the 40s north while reading
climb into the lower to mid 50s south.
.LONG TERM...(Tuesday night through Monday)
Issued at 310 PM EDT MON APR 22 2019
An active pattern through the middle/end of this week and through
the weekend will bring additional chance for precipitation,
especially this weekend. It isn`t out of the question that we could
see snow return to the Upper Peninsula this weekend; however, this
is highly dependent on how the system evolves as it tracks across
the region and how much cold air is drawn into the system.
Ahead of the first shortwave expected towards the middle of the
week, Wednesday morning will be rather chilly but temperatures
should rebound nicely into the 60s during the day. Shortwave energy
will track along the US/Canadian border gradually pushing a weak
cold front across the Upper Peninsula late Wednesday/Wednesday
night. Ahead of the front, warm and breezy conditions will push us
back towards elevated fire weather conditions. However, the
combination of recent rainfall and moisture/return flow bumping RHs
up into the 30-40% range, we may not quite reach the elevated
threshold.
Wednesday afternoon could see some rain shower activity with warm
air advection, but not really impressive with precipitation chances
until the main front arrives and moisture transport increases along
and ahead of the front Wednesday night into Thursday. As the front
clears the south central and far eastern parts of Upper Michigan
Thursday afternoon, a few models are hinting at some elevated
instability. Wasn`t enough to put thunder in the forecast, but
certainly not out of the question to hear a few rumbles of Thunder
across the south central on Thursday. Elsewhere, during the day on
Thursday conditions will dry out.
For the end of the work week, we will cool down and dry out.
However, a stronger storm quickly developing in the lee of the
Rockies and tracking towards the Great Lakes region will bring
return chances for precipitation Saturday into Sunday. While the
system will be quick-moving, the GFS/Canadian hint towards rapid-
intensification as it tracks towards and across the Upper Peninsula
due to a much stronger shortwave aloft compared to the ECMWF. The
stronger model solutions usher in much more widespread precipitation
and better chance for light snow Saturday night/Sunday morning. Will
be interesting to see how the models continue to trend with this
system over the up and coming days. Certainly a time period work
keeping a close eye on.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 635 PM EDT MON APR 22 2019
IFR/LIFR conditions will persist at all sites under occasional rain
into this evening. Although northeast winds are not as favorable for
lower conditions at CMX, expect cigs to lower with more persistent
rain. Conditions shoud improve to MVFR at IWD and CMX late tonight
and at SAW Tuesday morning and quickly to VFR first at IWD and last
at SAW tue morning.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 428 PM EDT MON APR 22 2019
Northeast winds of 15 to 25 knots are expected on the western end of
Lake Superior this evening with north winds 20 to 25 knots into
central Lake Superior tonight and to 30 knots over the east half
late tonight into Tuesday as low pressure lifts northeast from IA
toward Quebec. Otherwise, a quiet stretch of weather will continue
from midweek on as winds remain below at or below 20 knots.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Flood Watch through Tuesday afternoon for MIZ001>005-009-010-084.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Ritzman
AVIATION...07
MARINE...JLB