Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/21/19
Area Forecast Discussion
National Weather Service Bismarck ND
913 PM CDT Wed Mar 20 2019
.UPDATE...
Issued at 913 PM CDT Wed Mar 20 2019
Latest fog/stratus imagery loop and surface observations continue
to show a clear sky early tonight. Not much change in the high
resolution models with patchy fog overnight. Temperature/dewpoint
spreads well within 5 degrees of each other at almost all observing
sites. The RAP and HRRR indicate increasing winds above 300feet
agl after midnight, which should limit dense fog through a deep
column from forming or spreading, and favor more of a patchy
fog/ground fog situation. Areal coverage per RAP/HRRR/GFSLamp looks
to be highest just after midnight, then decrease towards daybreak,
most likely due to the reasoning above with more turbulence/winds
developing a few hundred feet above ground level. Current forecast
has patchy fog and will continue with this and monitor the trends
closely for any changes/updates.
UPDATE Issued at 623 PM CDT Wed Mar 20 2019
Latest satellite imagery shows a clear sky across western and
most of central ND, the exception being the Turtle Mountains south
into the James River Valley with a few high clouds. Mid/upper
level ridge dominates tonight with a clear sky overall. Patchy fog
tonight per HRRR/RAP/GFSLamp guidance. BUFKIT soundings show
turbulent mixing just above the surface becomes greater after
midnight, which would reduce the threat of dense fog through a
deep layer. A more likely scenario would be patchy ground fog/up
through 100ft agl towards daybreak Thursday.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 327 PM CDT Wed Mar 20 2019
Currently, low pressure was over Wisconsin with broad high pressure
over the Rockies and western Plains. Temperatures were in the mid
30s in the James River Valley and in the lower 50s in parts of snow-
free areas of McKenzie , Billings, and Golden Valley counties in far
western North Dakota, providing another day of slow snow melt.
Tonight, high pressure will shift off to the south. Fog is possible
with ample boundary moisture remaining as snow continues to melt,
but westerly winds may be enough to prevent widespread fog
development. Thus have added a mention of patchy fog across our area
for tonight, with lows mainly in the 20s.
On Thursday, expect another mostly sunny day with broad upper level
and surface high pressure over much of the Northern Plains. Looking
for highs from the upper 30s/40 again in and around the James
Valley...to mid 40s in northwest and central ND...to the lower/mid
50s in the far west.
.LONG TERM...(Thursday night through Wednesday)
Issued at 327 PM CDT Wed Mar 20 2019
Thursday night and Friday, the western Canada upper level ridge
remains intact, with a developing low undercutting the ridge over
the 4-Corners area Thursday night...lifting north into Wyoming on
Friday. Near average temperatures expected Thursday night and Friday
with lows in the upper teens and lower 20s, and highs from the upper
30s to mid/upper 40s.
Saturday and Sunday:
Saturday, the ridge dampens as a large upper low approaches Hudson
Bay from northern Canada, and the aforementioned developing
low/trough approaches from Wyoming. Look for highs on Saturday from
the upper 30s to around 50 ahead of the system. The low pressure
system will then bring a chance of rain/snow Saturday night and
Sunday into western and central North Dakota as the low meanders
eastward into eastern SD/NE. On Sunday, look for cooler conditions
with brisk northerly winds as cold air from central Canada plunges
southward. Expect highs Sunday in the 30s and lows Sunday night in
the teens with chances of rain and snow.
After another cool day Monday, warmer conditions expected on
Tuesday and Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 623 PM CDT Wed Mar 20 2019
Overall, expect VFR cigs/vsbys along with patchy fog. With the
patchy fog, as of now, visibilities at KBIS/KISN/KMOT/KJMS have
been coded with 6SM BR. High uncertainty right now if fog will
form at each terminal. Will monitor through the evening and amend
the forecast as needed.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JV
LONG TERM...JV
AVIATION...KS
Area Forecast Discussion
National Weather Service Grand Forks ND
925 PM CDT Wed Mar 20 2019
.UPDATE...
Issued at 925 PM CDT Wed Mar 20 2019
Expecting some patchy fog to develop across the region tonight.
The latest HRRR model runs indicate the best location for fog
development is from around Fosston to Fergus Falls. Will monitor
and increase coverage if needed. Dense fog is not out of the
question for any fog that does develop tonight.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 305 PM CDT Wed Mar 20 2019
Temperatures and fog formation will be the main issues for the
period.
Some clouds in our far eastern counties but otherwise mostly clear
with sunshine helping temperatures reach the mid to upper 30s this
afternoon. There has been continued ripening of the snowpack and
low level moisture will be abundant thanks to melt we have been
getting. The center of the surface high will move from the high
plains of MT/ND southeastward into SD and Nebraska overnight. This
will allow winds over our area to shift from a more northerly
direction to the west and southwest. The winds will provide some
mixing and the westerly direction is not very favorable for fog.
On the other hand, there will be some weak warm air advection and
dew point depressions will be low. Not super impressed with fog
but included a patchy mention across the western two-thirds of the
CWA late tonight and into tomorrow morning.
Tomorrow, a shortwave will be digging down from Ontario into the
Great Lakes. Not much precip expected from this as most of the
activity will be to our northeast, but it will help push a
backdoor cold front into the CWA for Thursday. This will negate
the warm air advection we were getting overnight, and temps
tomorrow should be fairly similar to today in the mid 30 to upper
30s, although if we get more clouds than expected it could be a
touch cooler.
.LONG TERM...(Thursday night through Wednesday)
Issued at 305 PM CDT Wed Mar 20 2019
Upper north to northwest flow regime will transition to a briefly
building upper ridge over the Northern Plains during the late week
into weekend period. Milder temps from the upper 30s into the 40s
will continue along with our run of mainly dry weather.
Decent spread in guidance regarding evolution of upper low as it
moves from Four Corners across the Rockies and towards the Northern
Plains. Operational GFS is still rather high on the QPF when looking
at other guidance. Operational GFS is in line with the highest
outliers on GEFS with clustering much lower on amounts. Due to low
confidence we collaborated and came up with slight chance/chance
PoPs in place just to message the potential, but beyond that we will
have to see where things trend.
Cooler temps to begin next week, with lower to middle 30s, before
moderation back in to the 40s heading toward mid week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 649 PM CDT Wed Mar 20 2019
Warm air will push eastward in the low levels tonight, and given
the amount of low level moisture in the air, fog or low stratus is
not out of the question. However, probability seems low at this
time. The latest HRRR bring IFR cigs/vis from Fosston/FSE south
through FFM and AXN tonight. However, MOS guidance from both the
NAM and GFS are mixed with fog/stratus potential tonight. Have
kept it out for now but will monitor and amend TAFs if trends lean
that way.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Knutsvig
SHORT TERM...JR
LONG TERM...WJB
AVIATION...Knutsvig
Area Forecast Discussion
National Weather Service Hastings NE
616 PM CDT Wed Mar 20 2019
.SHORT TERM...(This evening through Thursday)
Issued at 259 PM CDT Wed Mar 20 2019
We are in a quiet period for a few days in between weather
systems. Aside from the wind, the dry and fairly seasonal
conditions today have been a nice change from the recent cool
and wet weather...and temps have risen into the 50s this
afternoon.
Heading into tonight, surface high pressure will build southeast
from the Dakotas and settle across south central Nebraska/north
central Kansas by daybreak Thursday. The biggest concern tonight is
whether or not we see fog develop and if so, how widespread/dense.
Models are in good agreement that low temps tonight will be several
degrees below crossover temps, suggesting the potential for dense
fog. Caveat will be winds...even though winds will be light, they
will be from a west/northwest direction which are generally not
favorable for fog. Confidence in fog potential is not high,
especially with HRRR not indicating fog development, so for now,
have not deviated from the current forecast and subsequent shifts
will need to monitor.
The surface ridge axis migrates east Thursday and heights rise aloft
as upper ridging builds onto the Central Plains. The airmass
moderates several degrees under the influence of the upper ridge and
temps are expected to top out near or in the 60s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 259 PM CDT Wed Mar 20 2019
Enjoy the next couple of days as the dry and mild/seasonal
weather lasts through the end of the workweek. In a progressive
pattern, the next system moving through the Rockies and across the
plains will bring another round of rain to our region beginning
Friday evening and lasting through Saturday. Additional rainfall
on already saturated ground with standing water and high
water/river levels will not help our hydrological situation this
weekend. Rain amounts at this time through Saturday look to range
from roughly a quarter to a half of an inch. Also, cannot rule out
a little thunder Saturday afternoon across portions of our
southern zones as an axis of instability works north.
The early weekend round of rain is expected to move out early
Sunday, with much of Sunday featuring dry conditions so the entire
weekend will not be a rain out. A cold front and deepening
eastern trough will bring another round of mainly rain Sunday
night into Monday, however some snow may mix in with the rain
across our northern zones in the colder air.
Thereafter, the forecast dries out Monday night through Wednesday
and temps trend up by the middle of next week with 60s forecast for
highs Wednesday.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 612 PM CDT Wed Mar 20 2019
Overall, quiet conditions are forecast for this TAF period. For
the majority of this forecast, VFR conditions are expected. There
will be a small period of time early Thursday morning where there
is the potential for some fog to develop. There isn`t great
agreement among models, but do have 1SM/BKN010 in for both sites.
On either side of this period, plenty of sun is expected. Gusty
winds currently in place will diminish this evening, with the
lightest winds around sunrise Thursday. Otherwise winds will be
generally northwesterly.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Fay
LONG TERM...Fay
AVIATION...ADP
Area Forecast Discussion
National Weather Service Grand Rapids MI
1148 PM EDT Wed Mar 20 2019
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 321 PM EDT Wed Mar 20 2019
- Rain, at times mixed with snow, will continue through the
evening hours with locally up to an inch of accumulation
possible.
- Another wave will swing through Thursday night mostly dry but
make way for a blustery Friday.
- Saturday and Sunday look pleasant with another system possible
early next week (low confidence).
&&
.UPDATE...
Issued at 1007 PM EDT Wed Mar 20 2019
As secondary nrn stream shortwave drops in, we`re seeing another
flare up of precipitation over western sections of the area
behind the main batch which has now edged into eastern sections.
Although the ongoing light rain or mixed rain and snow will
eventually wind down overnight, areas of drizzle and fog will
linger. Widespread dense fog is not expected although some local
visibilities around 1/2 mile are possible.
There is some concern for a few slick spots developing overnight
across the interior of Central Lwr MI (north of I-96 and
near/east of Highway 131) where guidance shows temps falling to,
or slightly below, freezing. Bridges and overpasses would be most
susceptible as residual moisture on the roads could freeze up.
&&
.DISCUSSION...(This evening through next Wednesday)
Issued at 321 PM EDT Wed Mar 20 2019
As expected, precipitation has expanded northward this afternoon in
response to upper-level diffluence associated with a nearly
meridional (e.g. north to south) oriented jet streak over Minnesota
and zonal (east to west) jet streak over the Tennessee River
Valley. Snow has been mixing in at times, with areas along I-94
seeing as much as a coating on grass thus far. From this point
forward, we expect much of the same with rain at times mixing with
snow with up to an inch of snow on the grass. We still have
concern that a few slicks spots will be possible for the evening
commute (especially on overpasses that can cool at or below
freezing quickly). However, the impacts are expected to be local
enough such that a headline seems unnecessary.
Precipitation is expected to end from west to east around
sunset, but closer to midnight across our far east. Attention will
then turn to the west as a compact surface low pressure system
associated with the aforementioned northerly wave tracks toward
Lake Michigan. Interestingly, the 12Z suite of high resolution
model guidance suggests a band of low-topped convective showers
will accompany the surface low as it tracks toward Lower Michigan,
which seems feasible given a region of steep mid-level lapse
rates across eastern Wisconsin as indicated by the SPC RAP
mesoanalysis. I`ll be honest--I`m not sure how far southeast the
band will get but there is a fair chance that lakeshore
communities may see another round of showers (rain/snow mix) after
dark.
Thursday doesn`t look half bad with highs in the low to mid 40s,
partly cloudy skies, and westerly winds of 10-15 kts. Thursday
night, a fairly potent shortwave trough will dive south across Lower
Michigan but the low-level moisture profiles at least at this
point suggest that precipitation will be scarce, likely
translating to light snow showers. The most noticeable impact will
be a blustery Friday as 850 mb temperatures bottom out to -10 C
or so, making way for surface high temperatures in the 30s with
northwest winds of 15 to 20 mph (e.g. wind chills in the 20s). As
skies clear during the evening, Friday night will be chilly with
lows dropping into the teens to lower 20s. Wind chills may flirt
with the single digits, especially in traditional cold spots.
On the bright side, Saturday looks great with sunny skies and highs
in the low to mid 40s thanks to a surface high pressure system
drifting through the Great Lakes. Sunday looks similar though clouds
should increase during the afternoon and evening hours as a cold
front/upper-level wave approaches from the north. Deterministic
forecast model guidance is somewhat "jumpy" with the evolution and
hence precipitation chances with the front centered on Monday, with
ensemble model guidance not being much more help (in fact, the
trend over the past few ensemble suites is for *less*
precipitation areawide). The discrepancies revolve around how a
surface wave ejecting from the Plains may interact with the
aforementioned upper- level wave, the details of which are all but
certain to change. For now, we`ll continue low-end chances for
precipitation.
Looking far head, there is a strong signal in ensemble model
guidance for a dry and sunny period during the middle portion of
next week with a return to active weather toward the first of April
(no joke).
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1142 PM EDT Wed Mar 20 2019
IFR/LIFR conditions will continue overnight and Thursday morning
due to low cigs and fog. Conditions will only slowly improve to
MVFR by Thursday afternoon as cigs/visbys improve. Conditions will
then continue to slowly improve to VFR at all the terminals by
late afternoon and evening.
&&
.HYDROLOGY...
Issued at 321 PM EDT Wed Mar 20 2019
The Grand and Muskegon Rivers remain high after the widespread
rainfall and snowmelt last week. Flood warnings remain in effect for
the Grand River at Comstock Park and Robinson Township, although all
locations have crested and water levels are declining. Meanwhile, a
flood advisory remains in effect for Newaygo County as frozen ground
continues to limit the ability of the standing water to drain away
from some roads and buildings.
A mix of rain and snow is falling today generally along and south of
I-96. Up to one-half inch of rain is expected in some areas. This
will cause the smallest streams in the area to rise a bit, but is
not expected to result in any hazardous conditions, and should not
reverse the downward trend on the medium and larger rivers. However,
it could aggravate the problem of ponding and stranded water that is
ongoing in Newaygo county.
The next chance for widespread precipitation does not move into our
area until Sunday night/Monday of next week, but at this point it
looks like the worst of this storm may stay to our south. Otherwise,
generally quiet weather is expected for the next week or so, with
continued gradual melting of any snow that remains on the ground.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Meade
SYNOPSIS...Borchardt
DISCUSSION...Borchardt
AVIATION...Laurens
HYDROLOGY...AMD
Area Forecast Discussion
National Weather Service Wilmington NC
902 PM EDT Wed Mar 20 2019
.SYNOPSIS...
Weak low pressure just off the NC coast will slowly move
northward and onshore tonight between Cape Fear and Lookout
early Thursday, spreading light to moderate rain mainly across
Southeastern North Carolina. Dry weather will return Thursday
and continue through the weekend as high pressure builds in from
the northwest. Low pressure and a cold front will spread clouds
and rain into the Carolinas late Monday into Tuesday, followed
by high pressure for Wednesday.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 830 PM Wednesday...Models move the 1012 to 1015mb low
onshore between Cape Fear and Lookout around or just after
midnight tonight. Decent lift ahead of the low will support
light to moderate rain east of the low`s track this evening and
overnight. West of the low will experience patchy light rain or
drizzle. Additional rainfall totals overnight could see one
quarter to one half inch across the ILM NC Coastal counties and
a quarter inch or less for the inland ILM NC Counties. For the
remainder of the ILM CWA a trace to one tenth of an inch. POPs
will drop off from SW to NE from late in the pre-dawn Thu hrs to
1 to 3 hrs after daybreak Thu. Have adjusted temps/dewpts due
to recent trends and latest HRRR runs.
Previous.........................................................
As of 300 PM Wednesday...A sharpening coastal trough off the
South Carolina coast should become a closed surface low over the
next few hours. Models are nearly unanimous that the low will
move northwestward toward Cape Fear late this evening. Shallow
isentropic lift west of the low has led to a rather solid canopy
of low clouds and spits of light rain across much of the Pee
Dee region this afternoon. This has not been well-captured by
the 12z models, but should largely dissipate by this evening as
easterly winds along the 290K theta surface (approximately 3000
ft AGL) weaken, then reverse overnight.
A more significant batch of heavier rain continues to organize
near the coastal trough southeast of Cape Fear. This is
associated with much deeper moisture and even some shallow
convection along the west wall of the Gulf Stream. Models show
this rain moving northwestward ahead of the surface low this
evening, mainly impacting the Wilmington area. The potential for
a half inch of rain or more exists north of Cape Fear this
evening, with most locations elsewhere picking up only a tenth
of an inch at best. Rain should end from south to north as zone
of ascent ahead of the surface low moves farther inland by late
this evening, but low clouds in the residual cold inland airmass
will wrap back down toward the coast overnight. Lows are
expected to fall into the lower 40s with some mid 40s in the
Cape Fear area.
A mix of clouds and some sun is expected Thursday morning as a
shortwave moves across the area, but enough sunshine should make
it through for highs to surge into the 60s. Mid-level
temperatures will remain very cold throughout the day (-6C at
700 mb, -22C at 500 mb) so steep lapse rates will probably
result in some cumulus developing despite surface dewpoints
around 40F.
As a second energetic shortwave should across during the evening
with an associated surface cold front. Even steeper lapse rates
from the surface up through around 15kft should develop.
Surface-based CAPE could grow to 200-300 J/kg as lower
tropospheric winds become westerly at 30-40 kt. The result could
be a broken line of gusty showers zipping across the area.
While the pattern Thursday night doesn`t look quite as dynamic,
this brings to mind an interesting wind event that took place on
March 7, 2004 when a stratospheric intrusion behind a sharp
shortwave encountered a similarly deeply- mixed airmass and
strong lower tropospheric winds. The result was a large area of
damaging winds 45-65 mph across much of NC. Again, this pattern
doesn`t look quite as dynamic but I wouldn`t be surprised to see
some breezy winds develop.
&&
.SHORT TERM /FRIDAY/...
As of 3 PM Wednesday...Axis of sharp mid-level shortwave will
be off the coast Friday morning. Very dry air through the depth
of the column will persist through most of the period, until
some upper- level moisture begins to work in from the west
Saturday night. A second shortwave will develop into a closed
low as it drops across the Great Lakes and across the Mid-
Atlantic states Friday- Friday night. The associated energy and
moisture are expected to remain to our north, with the cold
frontal passage occurring across the forecast area in the 00-06Z
Saturday time frame. Cool high pressure will build into the
area behind the front, and settle over NC/VA Saturday night.
High temps Friday should climb into the mid 60s...close to
climatological norms, but a few degrees cooler Saturday given
northwesterly surface winds. Lows Friday night generally upper
30s north to low 40s south. Slightly cooler Saturday night,
with fair radiational cooling conditions. Lows are expected to
drop into the mid 30s north to near 40 south.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
As of 3 PM Wednesday...Upper ridge axis and surface high pressure
will shift off the coast Sunday. West-southwest winds from the
surface through 250 mb will begin to usher moisture, and warmth,
ahead of another mid-level trough axis and surface cold front,
and models suggests fropa in the early morning hours Tuesday.
PoPs will begin to ramp up Monday into Tuesday, followed by deep
layer drying Tuesday night and Wednesday. Temps Sunday and
Monday will trend higher, reaching mid and perhaps even some
upper 70s by Monday. Cooling down a bit Tuesday and Wednesday
with highs in the 60s.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
As of 00Z...Generally poor flying conditions are expected for
much of the night, especially nearer the coast as rain works in
off the coast with attendant CIGS in the 0.5 to 1.5 KFT range.
Winds will become westerly from south to north overnight as the
coastal low moves north, bringing an end to the rain and
allowing for the return of VFR conditions all areas in the 12
to 16Z time frame. KLBT TAF has been issued as NIL due to too
much variability in the ceilings this evening and overnight.
Extended Outlook...VFR Friday through early next week.
&&
.MARINE...
As of 845 PM Wednesday...Sub 1015mb sfc low just offshore and
south of Cape Fear, will follow a NNE track, moving onshore
between Cape Fear and Lookout by or just after midnight tonight
and reaching the Albemarle sound by or just after daybreak Thu
as a 1010mb low. There will be variability in direction to the
winds this evening and overnight with the stronger wind speeds
along and east of the low`s track. This evident in the trends of
the local buoy network. Significant seas have also responded due
to the stronger onshore winds east of the low. Expect seas to
remain elevated especially from Cape Fear northward even when
winds drop below SCA thresholds later overnight. VSBY in the 1
to 3nm range overnight from light to moderate rains mainly in
the vicinity and locations east of the low`s track. Elsewhere
will see vsby in the 3 to 6 nm range overnight in patchy light
rain.
Previous........................................................
As of 300 PM Wednesday...Low pressure developing near the west
wall of the Gulf Stream should move northwest and toward Cape
Fear this evening. Strong north-northeasterly winds earlier
today gusted to gale force for several hours at the Frying Pan
Shoals buoy and at the offshore Wrightsville Beach CORMP buoy.
These winds have since diminished to 15-20 kt and the Gale
Warning will be replaced with a Small Craft Advisory with the
afternoon update.
As the low moves inland this evening, wind should turn west to
northwesterly across all of the coastal waters, with speeds
generally 15 kt. Strong winds of the past 12-24 hours built an
impressive easterly swell which should keep wave heights
elevated significantly above what local winds would suggest
through Thursday. A cold front should move quickly offshore
Thursday evening, with another shot of moderate northwesterly
winds to follow.
Northwest flow is expected through Friday morning on the order
of 15-20 knots as high pressure builds in the wake of a cold
front. The gradient will relax through the afternoon and winds
will remain offshore, through becoming a bit more westerly.
Another cold front will push across the waters Friday evening,
with winds becoming northwest once again. Gusts over 20 knots
will be possible immediately behind the front, diminishing
early Saturday as high pressure builds over the Carolinas.
Surface high pressure will drift across the waters Sunday,
bringing southerly return flow Sunday night and Monday. Wind
speeds will trend up Monday and Monday night, and become
southwest ahead of a cold front, which will cross the waters
early Tuesday. Wind gusts may reach 25 knots behind the front,
and lead to Small Craft Advisory conditions Tuesday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...Coastal Flood Advisory until 9 PM EDT this evening for SCZ054-
056.
NC...Coastal Flood Advisory until 9 PM EDT this evening for NCZ106-
108-110.
Coastal Flood Advisory until midnight EDT tonight for NCZ107.
MARINE...Small Craft Advisory until 6 AM EDT Thursday for AMZ254-256.
Small Craft Advisory until 6 AM EDT Friday for AMZ250-252.
&&
$$
SYNOPSIS...CRM/DCH
NEAR TERM...DCH/TRA
SHORT TERM...CRM
LONG TERM...CRM
AVIATION...DCH/RAN
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
835 PM CDT Wed Mar 20 2019
.UPDATE...
835 PM CDT
For Evening Update...
Increased pops across the eastern half of the forecast area this
evening, and extended some low chance pops past midnight for
these same areas, as high-res guidance maintains scattered showers
beneath mid-level vort overnight. Also raised mins in the west to
the mid-30s, as cloud cover and modest wind should help keep temp
up a bit overnight.
Evening GOES water vapor imagery shows a closed mid-level
circulation propagating southeast across eastern WI. Surface
analysis depicts low pressure reflection near Milwaukee at 01Z,
with a cold front trailing into IL and approaching the Fox River
Valley. Have seen an expansion of showers along/ahead of the front
this evening, with some 40-45 dBZ cores. High-res guidance such as
the HRRR seem to have a good handle on these trends, and have
bumped pops into the 40-60 percent range for these, highest from
about I-88 north over northeast IL. This main area of showers is
progged to continue to push east across the area into IN through
midnight, though with guidance maintaining some weaker and lower
coverage showers into the pre-dawn hours beneath the core of the
digging mid-level vort.
Winds shifting northwest behind the cold front overnight, and
current obs indicate temps dropping into the mid-upper 30s
upstream. Extensive stratus/stratocu noted in GOES IR imagery,
combined with a persistent 10-15 mph wind overnight should help
hold temps up in the mid 30s in most places, thus have raised mins
mainly across north central IL, about a category above previous
forecast.
Otherwise, going forecast looks on track with dry weather
Thursday, and no other changes made beyond tonight.
Ratzer
&&
.SHORT TERM...
225 PM CDT
Through Thursday...
Main concern for the short term forecast period will be lingering
pcpn trends for the remainder of the afternoon and this evening.
Latest radar imagery indicates that the main area of pcpn associated
with the quick-moving short wave is exiting off to the east, leaving
a very moist air mass it it`s wake. Low stratus and patchy fog
should persist through the afternoon. Another cold front is
expected to push into nrn IL early this evening and quickly push
south and east across the region. The latest high res guidance
continues to indicate the potential for some scattered showers along
and ahead of the front. There should be diminishing pcpn potential
following the fropa as well as a wind shift to northwesterly. Cooler
air will filter in behind the front, with lows tonight dropping into
the lower 30s. Thursday should be dry and with short wave ridging
moving across the area, skies are expected to clear out through the
day. With increasing sunshine, highs Thursday should be able to
climb into the middle to upper 40s, except for the northwestern
Indiana lake front, where northwest winds off of the relatively cold
Lake Michigan water should limit temperatures to the upper 30s to
lower 40s.
&&
.LONG TERM...
308 PM CDT
Thursday Night through Wednesday...
Generally quiet at the start of the period. Large vort max will
drop southeast across the Great Lakes region, with surface trough
and front moving south through the region. Dry conditions expected
with FROPA Thursday night, but expect cloud cover to be on the
increase once again into Friday morning. Slightly cooler air mass
will be in place, with high pressure then expected to build across
the region. This will continue a period of drier weather into the
weekend, with some moderation to the air mass then expected. Next
chance of rain arrives on Sunday, as mid/upper level trough moves
through the central CONUS. Confidence for rain across the region
is on the higher side, with overall coverage and amounts remaining
lower. This is due to the some variability with the track of the
associated low and approaching cold front. High pressure builds
back across the region early next week, but with a colder air mass
moving back in across the region.
Rodriguez
&&
.AVIATION...
For the 00Z TAFs...
The forecast concerns for the Chicago area airports are:
- Scattered showers this evening into early overnight
- Patchy MVFR clouds this evening and then more solid overnight
into Thursday morning, including possibly IFR
- Winds turning northwest later this evening, then potential of
them becoming close to due north Thursday morning
Low pressure over Lake Michigan this evening will slowly move into
lower Michigan overnight. In response, a cold front will shift
over the area mid-late evening. With the front and the associated
upper system, scattered showers will be passing tonight,
especially through early overnight. Confidence is lower later into
the night but some showers may linger until daybreak. Clouds will
lower to MVFR behind the front and may reach IFR Thursday
morning. Confidence in IFR was a little too low to mention at this
time. Clouds should clear from west to east during Thursday
afternoon, however more MVFR clouds look to return later Thursday
night.
Winds will turn northwesterly with the frontal passage this
evening. These will have occasional gusts, possibly to the lower
20 kt range. During the morning, winds may veer as much as to 360
degrees, and confidence in this is low-medium right now. Winds in
the afternoon should turn more westerly as the low pressure pulls
further away.
MTF
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service San Francisco Bay Area
900 PM PDT Wed Mar 20 2019
.SYNOPSIS...Scattered showers are possible across our southern
coastal areas late tonight and Thursday morning, but most
locations are expected to remain dry through Thursday. The next
frontal system is forecast to push across the region on Friday and
Friday night, followed by mainly dry weather Saturday into
Sunday. Unsettled weather is possible throughout at least the
first half of next week.
&&
.DISCUSSION...As of 9:00 PM PDT Wednesday...Except for isolated
showers over southern Monterey County, KMUX radar shows that
shower activity has ended across our area. An upper low still
remains offshore, currently centered about 150 miles west of San
Francisco. This low is forecast to track to the southeast
overnight and move inland near Monterey Bay late tonight. An area
of showers is forecast to track to the southeast with the upper
low, but models agree that this incoming shower activity will only
impact a small portion of our area. The 00Z NAM forecasts light
shower activity along the Big Sur Coast and in the Santa Lucia
Mountains late tonight and Thursday morning. The 18Z GFS and
latest HRRR forecast scattered showers near the Monterey County
coast and isolated showers as far north as the San Mateo County
coast late tonight and Thursday morning. In addition, scattered
shower activity is also possible over the higher terrain of
southern Monterey County and southern San Benito County on
Thursday afternoon. But for most of our forecast area, including
the bulk of the SF Bay Area, dry weather conditions are
anticipated through Thursday. Temperatures on Thursday are
forecast to be similar to today, or perhaps slightly warmer.
The next system, currently seen on satellite in the southern Gulf
of Alaska, is forecast to track to the southeast and spread
rainfall across our area on Friday and Friday evening. Light warm
advection rain may begin to develop on the North Bay Coast as
early as a few hours prior to sunrise Friday. This light warm
advection rain is then expected to spread across most of the SF
Bay Area on Friday morning. Rain rates are then forecast to
increase as a cold front sweeps from northwest to southeast across
our area on Friday afternoon and evening. Rain rates could be
briefly heavy just ahead of cold frontal passage, especially
across the northern portion of our area.
Rainfall totals through Friday evening are forecast to range from
less than a tenth of an inch in our southern-most inland valleys
to as much as an inch in northwest Sonoma County. Most locations
are expected to pick up between 0.25 and 0.75". Southerly winds
are forecast to pick up just ahead of the cold front on Friday
morning, but winds are not expected to be overly strong with
highest gusts of about 35 mph possible near the coast from San
Mateo County northward.
A few post-frontal showers may linger into Saturday. But for the
most part the upcoming weekend looks dry across our region.
Temperatures will start off about five degrees cooler than normal
on Saturday, but then warm close to normal by Sunday as a
shortwave ridge develops briefly over California.
Our weather next week is looking unsettled, with another round of
rain developing as early as Sunday night. Although the models
don`t agree all that well on the specifics, it looks as though a
couple of systems will impact our area through the middle of next
week, and that rainfall amounts with these systems will be higher
than what is occurring this week.
&&
.AVIATION...As of 4:30 PM PDT Wednesday...Scattered showers
and a few thunderstorms over southern Monterey and San Benito
Counties and in the Central Valley this afternoon could impact LVK
through 02Z. SCT-BKN clouds through this evening with cigs
staying 3500 ft or above. The upper low will move southeast across
the coastal waters later tonight. Rain expected to stay offshore
but cigs near 3000 ft are possible at MRY which will be closest to
the low. Also cannot rule out fog at STS tonight.
.CWSU SFO Approach Forecast...
.VAPs this afternoon through the evening.
.Confidence: MED-HIGH
Update. VAPS have occurred and are expected to continue through
the evening hours. The area remain conducive for low clds to
develop as moisture and an unstable atmosphere remain in place.
Expect cloud bases between FEW-SCT 020-030 with cigs around 050 or
higher. Expect the winds to remain out the WSW for the rest of
the afternoon
Vicinity of KSFO...SCT clouds at 3000 ft with cigs 4000-5000 ft.
Clouds will decrease after 04Z as we lose the daytime heating but
will increase again early Wednesday morning as the upper low
reaches its closest point to the area. West winds to 15 kt
decreasing after 09Z.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Clouds over the coastal hills could bring
MVFR conditions to MRY after 03Z with cigs around 3000 ft. Better
chance of VFR at SNS with cigs remaining at or above 5000 ft.
&&
.MARINE...as of 04:21 PM PDT Wednesday...Light to moderate west to
southwest winds will continue this evening across the coastal
waters before winds diminish overnight. Winds will increase and
turn southerly again tomorrow night and Friday as the next weather
system approaches. Moderate period west swell will continue today
and tomorrow before a longer period west to northwest swell
arrives on Friday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm until 9 PM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 9 PM
SCA...Rough Bar Advisory for SF Bar until 9 PM
&&
$$
PUBLIC FORECAST: Dykema
AVIATION: W Pi
MARINE: AS
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Area Forecast Discussion
National Weather Service Paducah KY
649 PM CDT Wed Mar 20 2019
.UPDATE...
Issued at 646 PM CDT Wed Mar 20 2019
Updated Aviation discussion for 00Z TAF Issuance.
&&
.SHORT TERM...(Tonight through Friday night)
Issued at 301 PM CDT Wed Mar 20 2019
Elongated upper low near Springfield Missouri as of 2 pm CDT
today. Baroclinic leaf and vorticity shear axis aligned very will
with precipitation shield depicted by surrounding radars. Dry air
entrainment into the eastern side of the trough at low levels
continues to limit effective rainfall deposition to the surface
until the lift and condensation overtakes the dry air. The NAM-WRF
and HRRR guidance continues to have consistent timing on the
translation of the precipitation shield through the WFO PAH
forecast area tonight and early Thursday.
A secondary lobe of vorticity and moisture is projected to move
in with the main trough axis as it absorbs/phases the southwest
Missouri low into the mean trough extending southward from Lake
Michigan. There should be enough lift to generate a small pocket
of light precipitation and clouds after midnight behind the main
line of showers this evening. As the trough rotates through the
area any lingering precipitation should be focused along the
Pennyrile region of west Kentucky before noon on Thursday.
Decided to keep temperatures a little cooler on Thursday over
southeast Illinois, southwest Indiana, and northwest Kentucky.
Given the expected cloud cover in the vicinity of the upper
trough and low level cold air advection north of the cold front
passing through the area, temperatures may not reach their
expected maxes in the lower 50s. Hedged toward cooler highs in
this area.
Otherwise, dry and gradually warmer conditions will be the rule
for the remainder of Thursday into Friday as a westward tilted
surface to upper level ridge moves in from the west. Given the
drier air, may see diurnal temperatures ranges of 25 to 30
degrees Thursday and Friday.
.LONG TERM...(Saturday through Wednesday)
Issued at 301 PM CDT Wed Mar 20 2019
High pressure over the region Saturday will keep the PAH forecast
area dry Saturday into Saturday evening. By late Saturday night,
models show low pressure over the Central Plains moving slowly east,
turning our southeast winds more southerly. This will result in
increasing moisture, and with the approach of a weak mid/upper level
trof, showers will spread from west to east on Sunday. Models take
the surface low across (ECMWF/Canadian) or just north (GFS) of our
region on Monday. This will keep widespread showers across the area
Sunday night into Monday night. Models show LIs near to just below
zero in our far west counties Sunday evening, and across mainly our
southern counties Monday morning, and included some slight chances
for thunderstorms in these time periods.
GFS is faster taking precipitation east of our region by late Monday
night, while ECMWF and Canadian linger precipitation through Monday
night and possibly into Tuesday. Kept chance pops in the forecast
for Monday night and mainly early Tuesday. With low temperatures
Monday night in the lower 30s, any lingering showers could mix with
a little light snow before daybreak, but nothing significant.
Models show high pressure building into the central U.S. on
Wednesday. This will give us dry conditions Tuesday night into
Wednesday.
Temperatures will be near seasonal Saturday through Monday night,
except Sunday night, which will be well above normal with cloud
cover and southerly winds. Cooler conditions will briefly settle in
Tuesday and Tuesday night behind the low pressure system, but
temperatures by Wednesday will moderate back to seasonal with plenty
of sunshine.
&&
.AVIATION...
Issued at 646 PM CDT Wed Mar 20 2019
Models on track with drop in ceilings through the evening from
VFR to MVFR as upper low in southwest Missouri and attendant
frontal boundary moves slowly east with its shield of rainfall.
Carried temporary MVFR vsbys with rain this evening, then after a
brief break, another round of lower (MVFR) bases with vicinity
showers possible with upper trof`s passage later tonight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
223 PM MST Wed Mar 20 2019
&&
.SYNOPSIS...
Warm and dry conditions will give way to more clouds and a slight
chance of rain as a weather disturbance crosses the area later today
into Thursday. Most lower desert locations will not see rain this
week and those who do should receive less than a tenth of an inch.
The best rain chances will be over the higher terrain north and east
of Phoenix. High temperatures will fall back into the lower 70s for
Thursday and Friday before warming back up over the weekend with 80s
expected again by Monday under high pressure.
&&
.DISCUSSION...
The springtime incoming weather system continues to be the main
weather story across the region. In spite of the fact that this
system continues to show a decent amounts of ascent and QG forcing,
limited available moisture is still expected to greatly limit QPF
amounts over the region. PWAT`s continue to be rather unimpressive
with this system, mainly in the 0.0-0.60 inch range, which is only 1-
2SD above the mean for this time of year. The latest GEFS QPF output
for KPHX is showing only 0.04 as a mean, with all members remaining
below 0.15 inch. QPF amounts are even less across SW AZ and SE CA.
High-res HRRR and NMM models are showing the best chances for
measurable rainfall across the lower deserts of South-Central AZ to
be in the early-mid morning hours on Thursday. with some shower
activity lingering into the afternoon across southern Gila County.
The main effects of the approaching system will actually be gusty
westerly winds, especially across extreme southwest Imperial County,
where localized gusts up to 55 mph are possible tonight into early
Thursday. The system will also be ushering in cooler air to the
western deserts, including far southeast California on Thursday,
with highs falling into the middle 70s across Se CA and struggling
to reach 70 across the lower deserts of south-central AZ.
For the rest of the forecast period, Friday into early next week,
dry conditions are expected as higher pressure returns to the area.
Temperatures will not change much on Friday but the central deserts
will warm into the upper 70s over the weekend, and then into the 80s
early next week. As an upper ridge builds in early next week, highs
in the Phoenix area are expected to climb into the upper 80s despite
a substantial amount of mainly high cloud spreading into the state
ahead of another trof developing along the west coast.
&&
.AVIATION...Updated at 1806 UTC.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
S-SE 10 knot winds gusting to 15-20 knots will begin to affect
the Phoenix terminals by 19-20Z resulting in a few hours of
crosswinds early this afternoon at PHX and DVT. Winds will veer to
the SW between 21-23Z with brief gusts in excess of 20 knots
before subsiding below 15 knots by early evening. BKN ceilings
will remain above 20 kft through this evening with a FEW ceilings
as low as 10 kft, but BKN to OVC ceilings will lower to 7-8 kft
as isolated shower activity pushes into the region with a cold
front. We have included VCSH at DVT and SDL between 8-13Z
primarily for showers closer to the higher terrain north of the
terminals, but chances are too low at PHX and IWA to include in
the TAF at this time. A thunderstorm is possible, but instability
will likely be too limited with the front overnight. BKN ceilings
will lift and S-SW 10-15 knot winds will return after sunrise.
Southeast California/Southwest Arizona including KIPL and KBLH:
An approaching weather system will result in persistent gusty
westerly winds today into tonight. Gusts to 20-25 kts are likely
at KBLH with gusts of 25-30 kts at KIPL. Wind gusts will decrease
below 15 knots late in the overnight hours and remain out of the
west. Skies will be SCT to BKN through early afternoon at IPL and
into the evening at BLH with cloud bases as low as 9-10 kft.
Convection is possible around 00Z at IPL and closer to 06Z at
BLH, but chances are too low to include in the TAF at this time.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Friday through Tuesday:
High pressure will be building across the region beginning late
Friday and should persist over the region into early next week.
Temperatures will also gradually warm through the period with
highs reaching normals by Sunday and above normal levels for early
next week. A drying period will also take place into next week
with minimum RHs lowering from the 20s Friday and Saturday to
10-15% by Monday. For the most part, winds will be light each day
with the exception of periodic daytime breeziness.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 5 AM PDT Thursday for CAZ562.
&&
$$
DISCUSSION...Percha/CB
AVIATION...LH
FIRE WEATHER...Kuhlman
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Thursday)
Issued at 323 PM CDT Wed Mar 20 2019
20Z water vapor shows a shortwave moving east along the MO/AR
boarder with another upper wave digging south through WI. An upper
level trough was noted along the CA cost with a couple shortwaves
within the flow. And in between these features was a high
amplitude ridge centered over the northern Rockies. At the
surface, a low pressure system was seen over WI with a broad ridge
of high pressure from the southern plains into the central
Rockies.
The forecast for tonight and Thursday is for dry weather to
persist. As the disturbed weather to the east of the forecast area
continues to move east, we should see general height rises across
the central plains as the upper ridge slides east with little
forcing for precip progged by the models. About the only question
in the forecast is whether some ground fog could develop. The NAM
and associated high res solutions show a signal for dense fog
overnight. However the NAM tends to be way to aggressive in
saturating the boundary layer. Meanwhile the RAP and GFS suggest
any boundary layer saturation would be pretty shallow with some
mixing occurring. So I think chances for ground fog are not high
enough to include in the forecast at this time. Skies tonight
should remain mostly clear helping lows to fall into the lower
30s. Have tweaked highs slightly warmer for Thursday. Models show
there to be good insolation through the day with relatively light
winds. So think the sunshine should help temps warm to around 60
for most areas.
.LONG TERM...(Thursday night through Wednesday)
Issued at 323 PM CDT Wed Mar 20 2019
Thursday night through Friday evening look to remain dry with
shortwave ridging over the area and a weak surface ridge delaying
any meaningful moisture advection north. The model consensus
wanted to bring highs on Friday into the middle 60s. Am a little
skeptical of this with models also showing a northerly wind and
some high clouds beginning to overspread the area. So have been
more reserved with temps on Friday ranging from the upper 50s
north to the mid 60s southwest.
Rain chances will be on the increase Friday night with rain
likely for Saturday and Saturday night. There is good agreement in
the models with the energy over CA now lifting northeast through
the state on Saturday. There are indications for some weak
elevated instability developing by Saturday afternoon, so have a
mention of thunder in the forecast as well. Although there isn`t a
strong indication for surface based instability. The highest
confidence in POPs is on Saturday and Saturday evening. By Sunday
and into Monday morning, there is progged to be some evolution in
the pattern where energy from the west Fujiwaras with the initial
wave or simply kicks out the first wave. There may be enough
moisture and instability around for scattered showers and storms
to develop, but the overall forcing parameters from the models
don`t show any period with strong vertical motion. Because of
this and the lower confidence in the models evolution of the
pattern, I was a little more conservative with the POPs keeping
them mainly in the chance category for Sunday through Monday. By
Monday night, northwest flow is expected to develop with surface
ridging building south into the central plains. This should bring
an end to the precip chances. Have highs on Saturday holding in
the 50s for the expected cloud cover and precip. There is some low
level warm air advection progged for Sunday. And since precip
shouldn`t be continuous, there could be some breaks in the clouds
helping warm temps into the lower and middle 60s. A frontal
passage and north winds developing on Monday is likely to knock
highs back into the 50s. Lows are expected to remain mild through
the weekend with readings in the 40s.
Mid level ridging is forecast to redevelop for Tuesday and
Wednesday. This should bring back the dry weather with moderating
temps. Wednesday looks to be the most likely time for a southerly
return flow and warm air advection. We should see highs at least
into the 60s on Wednesday and there is some potential for temps to
be warmer depending on the magnitude of the warm air advection.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 623 PM CDT Wed Mar 20 2019
A weak cold front will sag south across the area in the 3z to 6z
time frame causing winds to shift to a more northerly direction
albeit light at less than 8 kts. Winds just a few hundred feet
AGL are forecast to remain AOA 12kts overnight which along with
the modest pressure gradient should keep more widespread fog from
developing so will keep conds VFR at this point in time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Wolters
AVIATION...Omitt