Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/04/20
Area Forecast Discussion
National Weather Service Buffalo NY
929 PM EST Tue Mar 3 2020
Rain showers will exit the area from west to east this evening. A
few rounds of light rain and snow showers will then continue later
tonight through Wednesday with some minor accumulations across the
Tug Hill Plateau. High pressure will bring dry weather Thursday
before another area of low pressure brings some snow to the area
.NEAR TERM /THROUGH WEDNESDAY/...
Low pressure will continue to move down the Saint Lawrence Valley
tonight, with a trailing cold front now moving well east of the area
into eastern NY. The steady rain will exit Lewis County by late
evening, leaving a break in many areas. Another small area of light
showers has moved into portions of Western NY in response to strong
DPVA just ahead of a mid level vorticity maxima. A few more areas of
light showers will continue overnight in response to the passage of
the mid level trough, and also as marginal lake instability and
upslope flow develop on strengthening WSW flow.
The leftover rain showers will transition over to wet snow showers
overnight, first across higher terrain and last in the lower
elevations. West to southwest flow and lingering moisture combined
with cooling temperatures aloft will result in orographically
enhanced snow showers. Could be some minor accumulations for the
higher terrain east of Lake Erie, with the best chance for a 1-3
inch accumulation over the Tug Hill. It will breezy for a period
behind the exiting surface low, especially closer to Lake Ontario
with a several hour period where winds could gust to 35 to 40 mph.
Most overnight lows temperatures will fall back into the 30s, but
into the 20s across the higher terrain.
An upper level trough will pass across the Great Lakes into New
England on Wednesday. The upper level regime will promote weak cold
air advection into the region along with chances for rain
and snow showers. A weak wave will pass through PA from midday
through mid afternoon, and this may spread a brief period of wet
snow mixed with rain through the Southern Tier. Many of the high-res
guidance such as the WRF and HRRR suggest a narrow, more convective
line of rain/snow showers also developing for areas south of Lake
Ontario. High temperatures on Wednesday should reach the mid
30s to lower 40s.
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
An upslope westerly flow and lingering low level moisture will
combine to generate some scattered light snow showers east of
the lakes Wednesday evening...with these then fading out from
west to east during the second half of Wednesday night and early
Thursday as high pressure and much drier air builds across our
region. The axis of the high will then slowly drift into eastern
New York Thursday afternoon...while continuing to provide our
region with fair dry weather and at least some partial sunshine
through the rest of Thursday. With respect to
temperatures...overnight lows Wednesday night will be in the mid
to upper 20s...with highs on Thursday then ranging from 35 to
40 east of Lake Ontario to the lower to mid 40s elsewhere.
Another low pressure system and its parent sharp mid level trough
will then track from the Michigan Straits to Lake Ontario Thursday
night...while slowly pivoting its trailing cold front across areas
south of Lake Ontario. After a mainly dry first half of the
night...this system will spread increasing probabilities for some
light snow across our region from west to east overnight...which may
be mixed with some rain initially given marginal temperature
profiles for rain vs snow. Total nighttime snow accumulations from
this should be light...ranging from only a few tenths of an inch in
most locations to a half inch to an inch across the higher terrain
east of Lake Erie. Otherwise...lows will range from the 25-30 range
east of Lake Ontario to the lower 30s elsewhere.
As the mid level trough digs further southeastward on Friday...it
will continue to spur secondary surface cyclogenesis well offshore
of the mid-Atlantic coastline...with the initial surface low and
cold front gradually devolving into a fairly pronounced inverted
trough across central and eastern New York. The large-scale deep
cyclonic flow and plentiful moisture attendant to these features
will help to generate fairly widespread precipitation across our
region...with the prevailing northerly flow also helping to promote
some modest orographic and lake enhancement south of Lake Ontario.
As for ptype...boundary layer temperatures will remain marginal for
rain vs snow through early to mid afternoon...which will promote a
continued rain/snow mix through that time before steady cooling of
the column drives a changeover to predominantly snow by the end of
the day. Given expected temperatures...the generally light to modest
nature of the precip...and strong early March diurnal influences...
expect any snowfall accumulations during Friday to be relatively
minor and elevation-dependent in nature...with these ranging from an
inch or less across the lower elevations to an inch or two across
the higher terrain of the Southern Tier and Bristol Hills.
As we move into Friday evening scattered to numerous snow showers
will still be ongoing across our region...with the greatest
concentration of these again found south of the lakes due to lake
and orographic enhancement. As we progress through the night
though...high pressure and much drier air building in from the north
will result in these becoming much more widely scattered in nature.
Expect additional accumulations from these to be on the order of an
inch or less...with low level cold advection otherwise helping drive
low temperatures back down to 10-15 across the North Country...and
to the upper teens and lower 20s south of Lake Ontario.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Expect dry conditions as high pressure will dominate the forecast
through the weekend into the start of the work week. At first, the
area will be influenced by northerly flow Saturday morning,
producing lake effect snows south of the lakes. These snows will
diminish by midday Saturday as the wind shifts to westerly due high
pressure building into the eastern Great Lakes. The surface high
pressure will then slowly push into the mid Atlantic states and
eventually off the east coast Sunday through Monday, putting our
area in the outer edges of the high. This being said, the region
will be under general southwesterly flow which will allow for
temperatures to rebound back into the upper 40s and low 50s Sunday
The next chance for showers will come late afternoon/early evening
Monday. An upper level trough and associated surface low will track
northeast from the Midwest Monday afternoon reaching the eastern
Great Lakes Monday evening. As the low continues to track northeast
Tuesday, the area will likely see general rain showers throughout
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Steady rain associated with a surface low and cold front is exiting
the eastern Lake Ontario region this evening. This has been replaced
by an area of light showers in Western NY in response to the mid
level trough crossing the eastern Great Lakes. Conditions have
mostly improved to MVFR and VFR behind the cold front, with areas of
IFR CIGS and VSBY in BR relegated to areas northeast of the lakes as
moisture crosses the cold lake waters. The period of IFR northeast
of the lakes including KBUF and KART will be brief. Drier and cooler
air moving in overnight will allow for improving conditions.
A few more brief periods of rain/snow showers will continue
overnight and continue through Wednesday. A few of these showers
will briefly drop VSBY to MVFR and IFR, with mainly VFR between
showers. A mix of MVFR and VFR CIGS will continue, with the lowest
CIGS in showers and across higher terrain.
Wednesday night...MVFR/VFR with scattered rain/snow showers.
Thursday...Mainly VFR with scattered rain and snow.
Friday...MVFR/VFR with scattered rain and snow showers.
Saturday...MVFR/VFR with scattered snow showers.
Low pressure will track across the region through this evening.
On the back side of the low, west-southwest winds will increase
into tonight. There will be a period of small craft advisory
conditions on both Lake Erie and Lake Ontario tonight and
Wednesday. Winds will become west to northwest Wednesday night
behind a passing trough, maintaining small craft conditions on
Lake Ontario into Thursday morning.
Winds will become southerly and decrease later Thursday as a
ridge moves across the region.
Winds will sharply become northwest then northerly and increase
late Friday and Friday night as a cold front moves across the
lake, with another period of small craft advisory conditions
An area of low pressure moving across the area will bring about
a quarter to a third of an inch of rainfall into tonight. Some
minor snow melt will occur into this evening before colder
While the rainfall and snowmelt into tonight is not expected to
causing widespread flooding concerns there will be rises on area
waterways. The lastest river forecast has several Buffalo Basin
creeks reaching action tonight through Wednesday. The Rapids
forecast point on the Tonawanda Creek along with the Lancaster
forecast point on Cayuga Creek get within a half foot of flood
stage during this time and will be closely monitored.
MARINE...Small Craft Advisory until 6 PM EST Wednesday for LEZ040-041.
Small Craft Advisory until 1 PM EST Wednesday for LEZ020.
Small Craft Advisory until 11 AM EST Thursday for
Small Craft Advisory until 9 PM EST Wednesday for LOZ042.
Small Craft Advisory until 9 AM EST Thursday for LOZ045.
Area Forecast Discussion
National Weather Service Des Moines IA
812 PM CST Tue Mar 3 2020
...Updated for Near Term Weather Trends...
Issued at 812 PM CST Tue Mar 3 2020
Trends this evening have pointed to the wintry precipitation being
a bit farther south than previously thought by about a county or
two. This shift can be seen in the arriving 00z NAM as well as
recent runs of the HRRR and RAP. There is also some disparity in
the amount of QPF and resulting snow. Generally, guidance is
pointing towards around an inch or so of snow accumulations.
However, the NAM and the 1z NBM v3.2 shows a narrow strip of
higher totals from around Emmetsburg to Waverly. While the BUFKIT
NAM data has not arrived yet, the NAM has had a very cold
boundary layer this winter. Therefore, it is possible that it has
a colder than reality surface temperature now and in the near
future allowing for its higher snow totals. Further, Iowa DOT
road temperatures are still above freezing in the low 40s across
northern Iowa early this evening. If there were to be a narrow
band of higher snowfall, it would likely be east of I-35 where
the precipitation will fall with temperatures and road
temperatures that would support more accumulation. Will continue
to monitor environment and make adjustments as needed through the
evening and overnight.
.SHORT TERM.../Tonight through Wednesday/
Issued at 312 PM CST Tue Mar 3 2020
Confidence: Medium Tonight and High Wednesday
Main concern will be impacts from system tonight. Fast moving and
compact PV anomaly dropping southeast into Iowa overnight. This will
induce a weak surface low and associated H850 feature which are
forecast to track across central Iowa, with the Euro placing the sfc
low a bit farther south into southern Iowa. The low will track along
a cool front dropping south as well. Most of the 12z synoptic models
have backed off on qpf amounts with the hires models continuing to
suggest a band of higher qpf just north of the low and mainly over
northern Iowa. The better forcing arrives over our northwest
forecast area around 03z and quickly tracks east and generally
existing the east between 09-12z. Currently temperatures are in the
lower to mid 40s over the north with mid 50s in the south. Road
temperatures are in the mid 60s over much of the region this
afternoon. Farther north, daytime temperatures remain in the mid
30s as far north as southern North Dakota. Tonight the area will
first need to overcome the drier airmass and also today`s warmth in
the lower layers/roads prior to any real impacts tonight. With the
potential for up to .20 inches of qpf, even with a changeover across
the north, snowfall amounts continue to lean toward lighter amounts
of around 1 inch with locally slightly higher totals. Generally it
appears to be a battle between the arrival of the surface cooler air
and the precipitation crossing the area though temperatures aloft
will be cool enough to start off as snow. Tonight`s lows will
drop to the mid to upper 20s north while the south drops into the
lower to mid 30s. The system will quickly depart Wednesday morning
with a return of some sunshine as well as milder temperatures
again over the south during the afternoon. High pressure will
quickly slide east in the afternoon with a return of southwest
flow by late day.
.LONG TERM.../Wednesday night through Tuesday/
Issued at 312 PM CST Tue Mar 3 2020
Confidence: Medium to High
Other than wind, the bulk of the forecast will be quiet for the next
few days. Another storm will track along the US Canadian border late
Wendesday night into Thursday with a trailing front and stronger
mixing moving across our area. There remains a weak signal for some
light precipitation over northern Iowa or southern Minnesota during
from Thursday morning through Friday morning but confidence is
currently low regarding occurrence. Winds Thursday afternoon will
again be brisk with models suggesting that gusts may reach 40 to 45
mph during the late morning and afternoon hours. Will need to monitor
for potential headlines. As well, colder temperatures should filter
across the region by afternoon; especially north where highs are
more likely to be near the 40 degree mark while the south will still
see some lower to mid 50s. The drier airmass, stronger winds and
mild temperatures over the southwest Thursday could result in an
elevated grass fire situation, but will need to evaluate moving
forward. The remainder of the extended will see a rapid warm up over
the weekend with H850 temperatures reaching 8C by 00z Sunday and as
warm as 9 to 10C by 00z Monday. This should propel highs into the
60s by afternoon. Both the GFS and Euro are in decent agreement for
Monday into Tuesday with a well developed trough tracking east
across the region late Sunday night/Monday followed by high pressure
on Tuesday. Showers are likely into Monday then clearing later in
the day. Highs will cool Monday into Tuesday back into the 50s then
.AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/
Issued at 542 PM CST Tue Mar 3 2020
Winds will decrease this afternoon as clouds spread over the area
with a quick shot of wintry precipitation expected overnight,
mainly over the northern half of Iowa. This wintry precipitation
will arrive later this evening bringing MVFR and perhaps IFR at
times to FOD/MCW/ALO. Farther south, there could be a brief shower
at DSM. Conditions will have improved back into VFR by daybreak
Wednesday with light winds from the northwest becoming from the
southwest later in the day.
Area Forecast Discussion
National Weather Service Quad Cities IA IL
906 PM CST Tue Mar 3 2020
Issued at 855 PM CST Tue Mar 3 2020
A fast moving shortwave trough and associated low-level
frontogenesis, strongest near 850mb, will lead to light rain and
snow developing in north-central Iowa over the next few hours.
The precipitation is expected to increase in coverage as it pushes
east into eastern Iowa and northwest Illinois near or after
midnight. Most locations will only receive light rain and possibly
some mixed in snowflakes with no accumulation. However, for areas
north of highway 30 a changeover to all snow is likely,
especially along the highway 20 corridor. In this narrow zone,
which will probably be about a tier of counties wide, snow
accumulations of a dusting to around 1 inch are possible.
Can`t completely dismiss the potential for amounts near 2 inches
in a very narrow band - but only if heavier rates develop as
indicated by some recent hi-res models (3km NAM/NSSL/NMM).
Confidence is low on totals much above an inch, but it`s worth a
mention that localized higher amounts are possible. Main story is
to be prepared for stretches of slushy accumulation on pavement
where the steadiest snow develops. Otherwise, pavement will
probably just be wet where the snow is lighter.
Issued at 248 PM CST Tue Mar 3 2020
We were enjoying some gorgeous early March weather across the area
this afternoon with weak high pressure ridging passing overhead. Low-
level mixing resulted in windy conditions, with some gusts even
approaching advisory criteria briefly. Temperatures as of 2 PM
ranged from 41 in Dubuque to 55 in Keokuk, which was around 5 to 10
degrees above where we should be for this time of year.
Off to the northwest, water vapor imagery showed a shortwave over
eastern Montana into the western Dakotas, which was producing a mix
of rain and snow across the region. This shortwave will be the
primary driver of our weather for the short term period.
.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 248 PM CST Tue Mar 3 2020
1) Rain/snow expected across the area from midnight through mid-
2) Snow accumulation will remain below one inch.
Tonight through mid-morning Wednesday...
Quiet evening expected before weather turns active briefly.
Aforementioned shortwave is progged to quickly move across the north
central Great Plains this afternoon and evening, reaching the area
overnight. Guidance has been in good agreement of the shortwave
strengthening with its southeastward progression and increasing CVA,
with a closed surface low now progged to move over the area. This
surface low will increase lift and lead to precipitation development.
Forecast soundings are indicative of a mix of rain and snow as we
juggle with varying depths of temperatures above and below freezing.
As of this package, the best chance of seeing snow remains along and
north of Hwy 30 where there is a shallower depth of above freezing
temperatures to work with and better lift with the the developing
surface low (along with better potential for further cooling from
evaporation). Here, snowfall amounts of a few tenths up to one inch
will be possible with SLRs progged around 7-10:1. I will make note
here that the HRRR as of its 18z run is the most aggressive on QPF
(likely due to it trying to introduce convective elements) and
further south than other CAMs, which is the way it has been trending
over the past few runs. Running model certainty tools show that its
fairly high and an outlier, but I will pass along this concern to
the evening shift.
Further south, a mix of rain and snow to all rain is expected
through Wednesday morning. Precipitation should come to an end
around 6-8 AM.
Late Wednesday Morning through Wednesday Night...
Skies will clear out in time for the afternoon as another ripple of
high pressure ridging build across the area. Temperatures will not
be as warm as today due to a lower level of mixing and lighter
surface winds, but will still be above normal for early March.
.LONG TERM...(Wednesday Night through Tuesday)
ISSUED AT 248 PM CST Tue Mar 3 2020
1) Above normal temperatures and quiet weather primarily expected
through the weekend.
2) Slight chance of rain/snow over northeast Iowa and northern
Illinois Thursday, with windy condtions also expected.
3) Increasing confidence of active weather returning early next week.
Cold front is progged to pass across the region Thursday morning,
ushering in another area of high pressure and slightly cooler
temperatures. In addition, there is a slight chance of rain and snow
showers in northeast Iowa and northern Illinois where there is
better forcing near a surface low.
The main story with this front, however, will be the increase in
winds Thursday. Once the front passes, the pressure gradient between
the high and departing surface low will steepen, leading to an
increase in winds by late morning into the afternoon. Guidance is
hinting at winds gusts approaching 40 MPH during the afternoon
before subsiding during the boundary layer cutoff by evening.
High pressure will pass over the mid-Mississippi River Valley
Friday, keeping quiet weather overhead. Cool northwest winds will
limit highs to the mid to upper 40s.
Saturday through Daytime Sunday...
Another weekend, and another warmup! Increasing warm southerly flow
and strengthening mid-level ridging will allow temperatures to soar
once again heading into the weekend. Afternoon highs in the mid 50s
to low 60s are expected Saturday, with widespread highs in the mid
to upper 60s for Sunday. This is approaching normals we see in late
Sunday Night on...
Confidence continues to grow of active weather making a return to
begin the work week with an approaching front and increasing
moisture over the area. There are still uncertainties on rainfall
amounts and placement with this front and subsequent surface low, so
expect additional changes to this forecast as we head through the
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 600 PM CST Tue Mar 3 2020
A quick moving low pressure system will bring a band of rain and
snow to the area overnight. Snow is favored at KDBQ with a
rain/snow mix at KCID and mostly rain at KMLI. Minor slushy
accumulation is possible at KDBQ, especially if it snows
moderately for an hour or two. Overall, the impacts will be mainly
to visibilities and ceilings with MVFR likely and potentially a
brief 1-2 hr period of IFR.
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
828 PM CST Tue Mar 3 2020
Things have been slow going thus far on area radars as of 815 pm with
only some elevated returns beginning to stream into our western
counties from the southwest. Latest mesoanalysis shows little to no
CAPE at the present time which is why we aren`t seeing any sustained
convection at this time. However, the upper low remains southwest of
the area and as the low continues to move east, deeper forcing will
arrive which will introduce more instability to the area. The latest
run of the HRRR shows some better convection by 06z but the overall
trends of the latest runs show somewhat less of a trend of a linear
system with more of scattered thunderstorms within an area of rain.
Given the shear, some of these could still be strong to severe with
possible hail and damaging winds being the main threats. The best
chances for severe weather remain in the slight risk closer to the
path of the expected surface low.
.PREV DISCUSSION... /ISSUED 528 PM CST Tue Mar 3 2020/
Large scale forcing for ascent should approach the region over the
next 12-18 hours and bring periods of showers and storms to the area
terminals. This should begin at DRT around 2-3z lasting into the 11z
hour and at the I35 sites between 4z and 16z. Some of these storms
could be strong at times. In addition to the threat of storms,
MVFR/IFR conditions can be expected with both ceilings lowering
throughout the night and periods of visibility restrictions within
the heavier thunderstorm activity. Conditions should improve to VFR
at DRT around 14z and SSF/SAT around 16z with drying conditions. AUS
will likely remain MVFR throughout tomorrow, as wrap around moisture
lingers there on the backside of the upper low.
PREV DISCUSSION... /ISSUED 213 PM CST Tue Mar 3 2020/
SHORT TERM (Tonight through Wednesday Night)... The main forecast
issue in the short term is the prospect for severe convection and
heavy rainfall. The 12Z regional/global models are in good agreement
with the synoptic morphology of moving the shortwave trough now over
northwestern Mexico across Texas over the next 36 hours. This trough
is fairly high amplitude and slow moving, so we expect a little bit
longer than average period of sustained lift. Therefore, high PoPs
(especially Wednesday morning) are a given.
Despite the synoptic-scale agreement, the mesoscale details differ,
especially in regards to convective timing and intensity. There seem
to be two camps, with the Texas Tech WRF, HRW ARW, and other
typically "Dry Plains Environment" models keeping cellular
convection confined to the Rio Grande Plains, and generally only
bringing a weak line of storms across the rest of the area. In
contrast, the HRRR and HRW NSSL have a more coverage and stronger
cellular convection over the Rio Grande Plains, and carry an short-
line MCS through the eastern Hill Country and northern half of the I-
35 corridor. This is one of those cases where splitting the
difference is not an appropriate solution -- it will either be one
morphology or the other.
Given the release of CAPE earlier this morning over northern Mexico,
it seems a phase-shift to the east would be a preferred outcome for
tonight. This would also line up with the diurnal strengthening of
the LLJ. The result should be close to the TTech WRF and ARW
solutions of lesser activity, both in coverage and intensity. That
said, there could still be isolated hail and wind damage reports
with some of the stronger storms, especially on the Rio Grande
Plains, but the I-35 corridor, including Austin and San Antonio,
should see sub-severe storms.
Rainfall amounts through Wednesday night will vary widely, from 1/10
to 1/4 inch in the southeast coastal plains, to 1-2 inches in the
Edwards Plateau and Hill Country. One or two spots in Llano, Burnet,
or Gillespie counties may see up to four inches of rain. While there
main be some minor flooding of the low water crossings and other
typical spots, we do not foresee significant flooding.
The moderate to heavy rain should end by noon Wednesday, but
moisture wrapping around the low will maintain scattered showers
along and north I-10 until sunset Wednesday.
Strong gusty winds and low humidity in the southwestern corner of our
CWA, including Eagle Pass, will lead to Near Critical Fire Weather
conditions on Wednesday afternoon. Severity will be dependent on
rainfall amounts in the area. This area will need to be watched for
LONG TERM (Thursday through Tuesday)...
With the system moving out of the area to the northeast, ridging
builds in behind it. Thursday, cooler and drier air will take a few
degrees off of the high temperatures bringing back down to near
normal of upper 60s and low 70s. We maintain a dry forecast through
the weekend with winds switching back out of the southeast on
Saturday. This will kick off a warming trend into the beginning of
next week. Next chances for rain are Sunday through Monday with
abundant moisture in place as multiple disturbances in the southwest
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 66 47 68 46 / 90 80 10 0 0
Austin Bergstrom Intl Airport 61 68 46 69 45 / 90 80 10 0 0
New Braunfels Muni Airport 62 71 46 69 45 / 80 60 - 0 0
Burnet Muni Airport 55 59 43 67 43 / 90 90 10 0 0
Del Rio Intl Airport 56 67 45 73 46 / 70 20 0 0 0
Georgetown Muni Airport 58 62 45 68 44 / 90 90 10 0 0
Hondo Muni Airport 60 71 44 73 43 / 60 40 0 0 0
San Marcos Muni Airport 62 70 46 69 45 / 80 70 10 0 0
La Grange - Fayette Regional 64 75 48 68 45 / 70 80 10 0 0
San Antonio Intl Airport 63 75 47 71 47 / 70 50 - 0 0
Stinson Muni Airport 65 76 48 71 47 / 60 40 - 0 0
Area Forecast Discussion
National Weather Service Grand Forks ND
954 PM CST Tue Mar 3 2020
Issued at 951 PM CST Tue Mar 3 2020
Area of showers moving southeast thru central ND associated with
500 mb vort which is moving right over Bismarck. Few lightning
strikes even west of Mandan with this feature. Second night in a
row for that area. For eastern ND and NW/WC MN skies mainly clear,
though there are a few cloud patches in the nrn RRV and far NW MN
from clouds trying to move SE from Manitoba. Also some mid level
clouds brushing the far west/southwest fcst area with that wave to
the west. Will maintain eastern edge of low pops for far SW fcst
area, but most of the precip will miss us to the southwest. Temps
holding up pretty well within fcst range, exception being Langdon
airport dropping to 10F, but NDAWN at 16 there. So overall left
temp fcst as is. HRRR backing of a tad on fog development but
still has some and NBM has some as well but not as much as earlier
runs. Will still monitor. Best chc seems to be just east of the
Red in the eastern RRV from Crookston to Moorhead.
UPDATE Issued at 648 PM CST Tue Mar 3 2020
High pressure will move over the area tonight. Band of clouds to
our west will slowly spread east and overnight move into the DVL
basin as the high moves east. Another batch of clouds is near Lake
Manitoba and the La Portage Prairie region and it is sliding
slowly southeast. Unsure what to make of this cloud area so will
need to monitor. Main impacts overnight will be does fog form in
the area as the high moves through, with guidance still targeting
the mid Red River valley. Short range guidance insists on it in
various degrees of coverage. Will monitor, but confidence to throw
in fog at this point remains low.
.SHORT TERM...(This evening through Wednesday night)
Issued at 318 PM CST Tue Mar 3 2020
Weather and impacts for the short term continue to be driven by
clipper series. Weak surface high pressure will settle in over the
forecast area this evening and for the overnight. As the
remnants of the stratus deck erode or clear in this evening the
potential for fog development is being advertised in much of the
guidance for early morning time frame on both sides of the north
and central valley and across the Devils Lake basin. Similar
conditions to last week when guidance suggested fog and none
formed 3 out of 4 nights. So will leave out of the forecast for
now. In SE ND some light snow is possible as an area of precip
moves out of central ND with another clipper.
South winds develop quickly Wednesday morning in response to WAA
ahead of the next clipper. WAA wednesday afternoon and evening
could bring some light snow to NW MN. In the warm sector of the
clipper Wednesday afternoon and evening there is potential for
some shower activity, rain or snow possibly a mix, depending on
the strength of the warm nose and amount of saturation in the mid
.LONG TERM...(Thursday through Tuesday)
Issued at 318 PM CST Tue Mar 3 2020
12Z Thu - 00Z Sat
Water vapor loop indicated a short wave/jet streak approaching the
BC coast. Short wave will be moving out of the forecast area by Thu
morning however a secondary short wave will pass through Thu.
Deformation zones over northern Canada will shift east. GEFS
indicated most likely area for precip over northwest MN Thu.
Cold front will move south across the forecast area Thu. Windy
conditions are expected with good surface pressure gradient and
respectable pressure rises for Thu. Adiabatic low level lapse rates
are expected by late morning and into the afternoon Thu. Adiabatic
lapse rate layer is rather shallow up to around 3k ft. About 40 knot
wind potential to mix down. However cold advection is not that
strong Thu and pressure grad does shift east during the afternoon.
Travel impacts will be possible for Thu with high profile vehicles.
Blowing snow is expected to be minimal with relatively old
snowpack and recent mild temps.
Upper level ridge amplifies in the west and shifts over the Northern
Sat - Tue
Upper level ridge continues to shift east this period with warm air
moving into the area on Sat. Short wave to move across central
Canada and will send a shot of cooler air out of Canada on Sun.
Cooler air will be possible for Sun and Mon with some moderation by
Tue. Ensemble guidance indicates the potential for up to 4 inches
snow during a prolonged Mon/Tue period over parts of northwest MN
with less across the valley and eastern ND.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 533 PM CST Tue Mar 3 2020
High pressure will move southeast and be over the Red River valley
06z-09z period. Short range models picking up on light winds and
enough low level moisture to generate fog in the mid Red River
valley. Highly uncertain yet of this and for now will mention
possibility here but not yet include in GFK/FAR/TVF TAFs for the
overnight. Clouds from the west will move east late tonight into
Wed AM as warm advection kicks in.
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
627 PM CST Tue Mar 3 2020
.SHORT TERM...(This evening through Wednesday)
Issued at 208 PM CST Tue Mar 3 2020
Aloft: Low-amplitude W-WNW flow was over the NEB/KS per aircraft
wind data and RAP tropopause animations. A wk shrtwv trof was over
MT and sliding SE. This trof will rapidly cross SD/NEB this eve
followed by slightly anticyclonic WNW flow into tomorrow.
Surface: Wk 1014 mb high pres was along the KS/OK stateline. This
high will be squeezed by a wk low that will form near YKN and
then move into IL tonight. A developing cool front associated with
this low will cross the CWA this eve. Anticyclogenesis will then
occur over the Cntrl Plns tomorrow with return flow developing in
tandem with low pres moving acrs Srn Canada.
Rest of this afternoon: Mostly sunny...warm and breezy. Highs in
the low-mid 60s will occur 4-5 PM.
Tonight: Mostly clear. There will be a few clds around early that
could result in some sprinkles here and there. After 10 PM...
clear. Lows within a cpl degs of 30F.
Wed: Sunny. Becoming breezy after 18Z...espcly N and W of HSI with
G25-30 kt will be common.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 208 PM CST Tue Mar 3 2020
Pattern: No change in the main theme since mid Nov. Lots of W-E
flow off the Pac. Low amplitude will occasionally increase to
Aloft: The longwaves will amplify a bit Thu-Sat...and then
deamplify heading into early next week. The flow over NEB/KS will
be NW Thu...behind a deepening shrtwv trof moving into the Ern
USA. The moderate-amplitude ridge over the Wrn USA will cont E and
crest over the Plns Fri eve. Behind it...WSW flow will prevail
Sat-Sun. A shrtwv trof that originates off CA will move thru the
Desert SW and cross the Cntrl/Srn Plns Mon AM. Zonal flow will
occur in its wake Tue.
Surface: 1030 mb high pres will emerge onto the Plns Thu and cont
to strengthen as it gradually shifts into the MS Vly Fri and into
the SE USA this wknd. As the high moves away...breezy/very warm
return flow will remain over NEB/KS until a Pac cool front moves
thru Sun night. Nrn Plns high pres will then build in Mon- Tue.
Temps: Way warmer than normal with a warming trend thru
Sun...then temps return back to near normal Mon-Tue. Sat-Sun cont
to trend warmer and we`re now looking at 2 days with widespread
Precip: Dry until the frontal passage Sun night. Rain appears
likely Sun night into Mon. The ptype routine has some snow N and W
of the Tri-Cities...but that is based purely on sfc temps and our
lows are probably too chilly. Am expecting this to be all rain.
Let the NBM thunder probs dictate its inclusion. So there is now a
slight chance of thunder Sun eve. Both the GFS and EC have 50F
dwpts surging into the SE CWA to meet the front. That should
create sufficient/weak instability to support some thunder.
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 626 PM CST Tue Mar 3 2020
High confidence in VFR ceiling/visibility through the period with
clear skies the vast majority of the time, although these first
few hours will feature a fairly solid mid-level cloud deck
(ceiling around 10K ft.) along with the possibility of a few brief
sprinkles. That leaves winds as the main aviation issue, both at
the surface and aloft, as much of tonight will likely feature at
least marginal low level wind shear (LLWS). Read on for more
Generally speaking, most of the night and Wednesday morning will
feature a westerly to west-northwesterly breeze sustained in the
8-12KT range, although occasional gusts to 20+KT cannot be ruled
out (especially these first few hours). A more notable occurs late
morning into the afternoon, as direction transitions to
southwesterly sustained generally 14-18KT/gusts 19-25KT, before
subsiding a bit by late afternoon.
Have maintained the inherited mention of LLWS overnight, and
extended it by 1 hour, now focusing 03-10Z. In, short, winds
within roughly the lowest 1K ft. above the surface will increase
to around 40KT from the northwest, promoting generally 30-35KT of
overall- shear magnitude between the surface and this level.
Issued at 208 PM CST Tue Mar 3 2020
Near critical RH/winds this afternoon in some spots.
Critical RH/winds are expected Wed afternoon. So a RFW has been
posted for Dawson/Gosper/Furnas/Harlan/Phillips counties. Outside
of the warning...near critical.
Thu will be another day of critical or near-critical RH/wind.
Fri and Sat will be windy...but low-lvl moisture should come up
just enough to keep RH`s above 30%.
NE...Red Flag Warning from noon to 6 PM CST Wednesday for NEZ060-072-
KS...Red Flag Warning from noon to 6 PM CST Wednesday for KSZ005.
Area Forecast Discussion
National Weather Service Gray ME
745 PM EST Tue Mar 3 2020
After record high temperatures in some areas today, low pressure
will move in from the southwest tonight bringing a brief period
of rain before a cold front moves through Wednesday morning.
Mountain areas will see some snow. Wednesday will still be warm
but rather windy with temperatures cooling into the end of the
week. A brief ridge of high pressure will build into the region
Thursday before low pressure develop off the Eastern Seaboard on
Friday. This system will pass well east of our region Saturday.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Update...Warm advection wing of precip moving thru the heart of
the forecast area now. I have adjusted PoP to represent trends
with the band over the next few hours. Dewpoints are largely
above freezing across the area...so this is expected to fall as
rain overnight...except for the highest peaks. The next area of
precip will move thru late tonight with the S/WV trof itself.
Temps aloft will be sharply falling behind it...and precip may
briefly change over to snow before ending. Snow showers will
continue in the mtns.
Previous discussion...High temperatures will continue to fall
across portions of the region this afternoon.
12Z guidance in good agreement with the near term portion of the
forecast. Low pressure gradually develops as it moves up the
Saint Lawrence River Valley tonight. Rain will move into the
region this evening from southwest to northeast. The latest HRRR
continues to show two batches of precipitation with a second
area of rain arriving around and shortly after midnight.
Some snow may fall in northern areas with light accumulations.
Over the Presidentials, significant accumulations are possible
above 2500-3000 feet.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Skies clear tomorrow morning as low pressure intensifies and
exits into the Canadian Maritimes. A westerly gradient will
increase as the upper low features shift to the east. Warm
temperatures for this time of the year will allow for increased
mixing values as well. After coordination with adjacent offices,
will issue a wind advisory for Wednesday for all areas with the
exception of the Connecticut River Valley. This scenario
matches well with our neighbors.
Some minor additional accumulations of snow expected in the
mountains where upslope conditions will persist.
Temperatures will be above normal for this time of the year,
despite the cold air pouring into the region. Look for highs
well into the 40s over central and southern areas.
By Wednesday night, winds will still be gusty but slowly easing
slightly. A few upslope snow showers may continue over the high
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The ensemble and deterministic model solutions remain in good
agreement on the long wave pattern through the upcoming weekend
and the start of next week. Northern stream energy will dominate
this period. The question mark remains the degree of interaction
between streams in the Friday and Saturday timeframe...impacting
the timing and placement of the ocean storm. With the mean jet
position remaining nearby...it`ll be an active period but with
above normal temperatures as arctic air remains largely confined
to our north. The forecast period begins with weak ridging and
quiet weather for late Thursday into Friday. Northern stream
disturbance approaches from the Great Lakes Friday while a
southern stream disturbance emerges off the southeast CONUS.
Eventually this energy congeals into a single offshore
system...that could brush coastal sections with a period of light
snow or snow showers Friday night - early Saturday as the column
cools. The ensemble trend overnight is once again slightly further
offshore with this system with light QPF amounts confined to
southern and coastal sections. Behind this system...a ridge of high
pressure settles across the region during Saturday. A weak frontal
boundary may settle south into northern sections Saturday night
through Monday with clouds and widely scattered rain or snow
showers...as high pressure builds by to our south.
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
Short Term...VFR conditions early this evening will be lowering
to IFR and LIFR in low cloudiness and rain as low pressure
approaches from the southwest. Conditions improve Thursday and
Thursday night, however winds will be very gusty from the west
during this period with some gusts above 45 mph.
Fri PM- Sat AM...Sct MVFR and lcl IFR psb at coastal TAF sites in
Short Term...Have issued gales for the coastal waters for
Wednesday into Wednesday evening. Healthy westerly gradient and
cold air advection will allow for gale force winds over the
coastal waters. Wind will gradually ease late Wednesday night
into Thursday as low pressure continues to exit through eastern
Thu...SCA`s likely outside the bays.
Fri Night - Sat...SCA likely with Gales psb outside the bays.
Record highs for today...
Portland, previously 55 degrees set back in 1961. The Jetport
reached a high temperature of 61 degrees...breaking the old
Concord, previously 62 degrees set back in 1874. Concord
reached a high temperature of 62 degrees...tying the old
Augusta, previously 60 degrees set back in 1964. Augusta
reached a high temperature of 54 degrees...falling short of the
ME...Wind Advisory from 6 AM to 6 PM EST Wednesday for MEZ007>009-
NH...Wind Advisory from 6 AM to 6 PM EST Wednesday for NHZ001-002-
MARINE...Gale Warning from 6 AM Wednesday to midnight EST Wednesday
night for ANZ150>154.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
912 PM CST Tue Mar 3 2020
.SHORT TERM [Through Tomorrow]...
Overall there is not much change in the forecast but wanted to
toss out a few thoughts on the marginal severe weather outlook for
tomorrow. Frontal boundary is currently stalled from the Arklatex
WSW towards west central Texas this evening. Front should slowly
sag south but it will take it`s time doing it since there will be
an upper level low moving into central Texas with a positive tilt.
As this low moves east from the Big Bend area, there should be
increased large scale lift spreading over central Texas through
the morning hours. We could see a QLCS type line develop in
central Texas and move towards College Station/Crockett area in
the late morning hours. Instability is not all that great but any
interaction with the frontal boundary could increase shear locally
for a mesovortex spin up. Again, this is not a great environment
for severe weather just because instability will be marginal.
We hate cherry picking one particular deterministic model run, but
the last run or two of the HRRR like the 00Z run have also raised
an eyebrow with convection forming in the afternoon as a surface
low pressure organizes over the area. Boundary layer winds veer to
the W during the course of the afternoon and the frontal boundary
sags into the Houston area and down towards Wharton. South of the
boundary there will be 70+ dewpoints and possibly enough
instability for more robust convection. IF and that`s a big IF, a
storm can become surface based and track along the frontal
boundary then we might get an isolated severe storm. So we will
see if this forms but the lion share of models bring a dry slot
into the area and we get nothing. So in the end, we are just
hedging our bets and do not want to be caught off guard.
.PREV DISCUSSION /Issued 551 PM CST Tue Mar 3 2020/...
.SHORT TERM [Tonight through Wednesday Night]...
Further development of sea fog continues to be a concern in the
immediate term, with ample low-level moisture and light onshore
winds still present across the bays and the offshore waters. Some
inland areas could also see fog development this evening as we saw
overnight yesterday. As a result the Marine Dense Fog Advisory
has been extended through tomorrow morning, after which drier air
behind an advancing surface front and offshore winds should clear
the fog threat heading into the weekend.
The forecast for the rainfall event tonight and into tomorrow has
remained largely on track. Global model guidance continues to
indicate the upper low progressing eastward towards the Big Bend
region this evening and further into Central TX by tomorrow
afternoon. NAM, HRRR, and GFS show PWAT values surging to as high
as 1.7" by tomorrow morning, which is well into the upper
quartile of the climatological distribution for early March at
nearby sounding locations. As a developing surface low pushes
northeastward heading into the evening hours, sufficient surface
lift along a slowly advancing frontal boundary and favorable
divergence aloft in the exit region of an upper-level jet streak
will allow for increasing coverage of showers by Wednesday
morning. Greatest rainfall totals continue to be focused generally
to the north of the I-10 corridor, with GFS and ECMWF in good
agreement in showing a swath of higher values across the northern
counties of the CWA. Around 1-2" continues to look in store for
many locations north of the Houston metro area while totals drop
off to around 0-25-0.5" near the coast where dynamics remain less
favorable. Rainfall coverage gradually tapers off as the surface
low exits the region on Wednesday afternoon and the frontal
boundary pushes offshore.
SPC has maintained a marginal risk in its convective outlook for
portions of the northern half of the CWA. While convective
allowing models have indicated the potential for some stronger
storms developing to our west by tomorrow morning, the environment
that any storms progressing into the western counties will
encounter appears to be less favorable for stronger convection due
to limited instability. Nonetheless, some isolated thunderstorms
remain a possibility with tomorrow`s activity, particularly in the
.LONG TERM [Thursday Through Tuesday]...
Behind tonight and tomorrow`s active weather pattern, expect
calm, dry, and seasonable weather conditions to prevail heading
into the weekend as upper level ridging and surface high pressure
take hold over the central CONUS. Clearer skies, daytime highs in
the upper 60s to low 70s, and north to northwest winds will be in
store across SE TX through Saturday.
Look for a return to onshore winds and increasing moisture as the
surface high pushes eastward on Sunday, with rain chances
consequently increasing as we head into next week. Our next
potential period of active weather comes as a shortwave trough
digs into the south central CONUS on Monday.
.AVIATION [00Z TAF Issuance]...
Not much change in the big picture for this cycle, as VFR gives
way to degrading flight conditions through the night, along with
increasing chances of showers (and some storms from IAH
northward). Look for rain to come to an end at some point at the
end of the TAF period, with flight conditions to improve (slowly
inland, rapidly on the coast). However, have largely left this
out of this forecast cycle due to uncertainty in precise timing.
Look for more details in the 06Z TAF on this trend.
The onshore flow will persist into tonight and early tomorrow.
This will allow for areas of sea fog to continue to possibly
develop and become dense at times along the coast/bays and
into the nearshore waters. The long fetch that is in place
and helping to produce 3 to 5 foot seas should gradually
increase as pressures fall off to our west into Wednesday. Have
hoisted caution flags for the offshore waters beginning this
evening, and it is possible that these flags might need to be
stretched closer to the coast and maybe even raised to an
advisory later tonight or tomorrow. The Texas storm system and
associated cold front will move across our area during the day
on Wednesday and will eventually allow winds to shift to the
northwest and bring an end to the fog threat. The tightened
pressure gradient will eventually bring elevated winds and seas
to the area that will likely require caution and/or advisory
flags probably beginning Wednesday afternoon or evening and
especially on Wednesday night and Thursday. High pressure
influencing the area at the end of the week and moving off to the
east over the weekend will allow the north to northeast winds
at the end of the week to shift to the southeast over the weekend. 42
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 65 66 47 67 46 / 60 80 40 0 0
Houston (IAH) 67 72 51 66 50 / 70 70 20 0 0
Galveston (GLS) 63 68 54 64 55 / 60 40 20 0 0
GM...Dense Fog Advisory until 9 AM CST Wednesday for the following
zones: Coastal waters from Freeport to Matagorda Ship
Channel TX out 20 NM...Coastal waters from High Island to
Freeport TX out 20 NM...Galveston Bay.
SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CST Wednesday for
the following zones: Waters from Freeport to Matagorda Ship
Channel TX from 20 to 60 NM...Waters from High Island to
Freeport TX from 20 to 60 NM.
Area Forecast Discussion
National Weather Service Jacksonville FL
910 PM EST Tue Mar 3 2020
...ISOLATED TO SCATTERED SEVERE STORMS POSSIBLE WEDNESDAY MAINLY
NORTH OF I-10...
A line of weak showers is moving through parts of southeast GA
this evening associated with prefrontal trough. Some stronger
forcing associated with a shortwave trough/vort lobe is moving
through the FL panhandle, and coupled with more instability is
producing scattered showers and a few storms in that area. So
with these two areas of forcing, rain chances will increase over
the nrn half of the area through later tonight. Given the weak
instabilty though will have isolated thunderstorms rest of tonight.
Can`t rule out a strong to possibly severe storm toward 12z over
inland southeast GA, as subsidence inversion in the mid levels
weakens and allows for potential deeper convection. The stronger
cells would be most likely near a cold front that stalls over
southeast GA Wednesday morning. SPC shows marginal risk for severe
for southeast GA through sunrise Wednesday. Latest HRRR guidance
shows one or two stronger convective cells moving east- northeast
late tonight that end up weakening, likely due to moving further
away from higher instability to our west. For the update, will
adjust timing of precip a bit. Otherwise, temps and sky cover look
good with temps only slowly falling due to increased clouds and
light south- southwest winds. Min temps in the mid 60s, possibly
upper 60s in some locations.
South to southwest winds around 10-15 kt rest of tonight, with
seas near 3-5 ft. Winds appear to have decreased a bit since
earlier so will remove SCEC headline. Otherwise, forecast is on
.PREV DISCUSSION [724 PM EST]...
.NEAR TERM [Through Wednesday]...
The cold front entering the southeastern states will push
southeastward through southeast Georgia during the predawn and
early morning hours, accompanied by increasing showers and a few
embedded elevated thunderstorms after midnight across southeast
Georgia as diffluence aloft strengthens within the active
subtropical jet in place over our region. Steepening lapse rates
and the arrival of weak shortwave energy from the northern Gulf of
Mexico may develop a few strong thunderstorms along or just south
of the sinking frontal boundary during the predawn hours, with
the potential for a few right- moving supercell thunderstorms
developing along the FL/GA border or perhaps as far south as
Interstate 10 towards sunrise. Low stratus ceilings will likely
advect east-northeastward across north central Florida during the
predawn hours, where patches of locally dense fog may also
develop. Warm air advection should keep lows in the 60s nearly
The cutoff cyclone will pivot eastward across Texas on Wednesday,
resulting in the frontal boundary slowing its forward progress as
it moves across the FL/GA border. Strengthening isentropic lift
will likely develop moderate to heavy rainfall for locations north
of this stalling boundary, with a few embedded elevated
thunderstorms possible throughout the day across southeast
Georgia. We have issued a Flash Flood Watch for locations north of
a line from Pearson to Waycross to Jesup, where stronger lift
should result in widespread heavy rainfall through Wednesday
evening. A few of the short-term, high resolution models develop
isolated to widely scattered convection along the Interstate 10
corridor around sunrise, suggesting that a few right-moving
supercells may progress eastward along an outflow boundary
originating from overnight convection over southeast Georgia.
Steep lapse rates and strong westerly wind shear within the hail
growth zone could result in a few strong to severe thunderstorms,
with large hail and downburst winds being the primary threats.
This convection could impact the morning commute in northeast
Florida, so trends with the short term guidance will be closely
monitored overnight. A large temperature gradient will become
established over our area on Wednesday, with highs likely staying
below 70 for locations near the Altamaha/Ocmulgee Rivers, while
warm and breezy conditions boost highs to the mid and upper 80s in
north central Florida.
.SHORT TERM [Wednesday Night Through Friday Night]...
Cyclogenesis is expected along the Upper Texas coast on Wednesday,
with the upstream cutoff cyclone opening up into a potent
shortwave trough on Thursday as it moves east-northeastward across
the southeastern states. The frontal boundary in place along the
I-10 corridor may backdoor its way down the northeast Florida
coast on Wednesday night, followed by a brief surge of
northeasterly winds along the coast for locations north of St.
Augustine. There may be a brief lull in heavy rainfall overnight
over southeast Georgia before isentropic lift strengthens as the
storm system approaches from the west on Thursday morning. Lows
Wednesday night will range from the mid 50s near the Altamaha
River to the mid and upper 60s for locations south of the frontal
boundary in north central Florida and the Suwannee Valley.
Heavy rainfall will redevelop over southeast Georgia on Thursday
morning as the frontal boundary retreats northward as a warm front
Widespread rainfall totals of 3-5 inches with locally higher
amounts will be possible in the Flash Flood Watch area. Model
guidance otherwise remains in decent agreement on timing and
details as low pressure moves east-northeast from the Florida
panhandle early on Thursday morning across southeast Georgia
during the afternoon hours and off the South Carolina coast by
early evening. The warm sector will overtake all of northeast and
north central Florida, with the threat for a squall line of
strong to severe thunderstorms moving from west to east across
these areas during the afternoon and early evening hours.
Impressive west southwesterly speed shear continues to be noted in
model soundings, with 50-60 knot winds depicted at 850 millibars
(around 4,500 feet), steep lapse rates and CAPE values of
1,000-1,500 j/kg in the warm sector. Damaging wind gusts and
possibly a few tornadoes will be possible for locations along and
south of I-10 through around sunset. Highs on Thursday will range
from the lower 60s near the Altamaha River to the mid and upper
80s in north central Florida, while most locations along and south
of I-10 reach the 80s.
Low pressure will strengthen off the Carolina coast on Thursday
night, which will push this storm system`s cold front offshore
towards midnight. Convection should move offshore by early evening
as well, with northwesterly winds becoming breezy and driving lows
down to the mid to upper 40s across southeast Georgia and the
northern Suwannee Valley, with 50s elsewhere as cloud cover
decreases from northwest to southeast during the overnight and
predawn hours on Friday. Stronger cold air advection will lag this
storm system somewhat as a potent shortwave trough dives
southeastward from the Canadian Prairies across the Great Lakes
region on Friday, which will sharpen troughing along the eastern
third of the nation by late Friday. A dry air mass, plenty of
sunshine and breezy northwesterly winds will allow highs to climb
to near early March climatology on Friday, with highs generally
reaching the 65-70 range, except lower 70s in north central
Florida. Cold air advection then will arrive on Friday evening,
driving lows down to the 35-40 degree range inland by sunrise on
Saturday and 40-45 at the coast, with wind chills around freezing
.LONG TERM [Saturday Through Tuesday]...
Deep troughing that resides along the U.S. eastern seaboard on
Saturday will progress offshore on Sunday, allowing for zonal flow
to develop by late in the weekend and early next week. Strong
surface high pressure extending from the Great Lakes region into
the Tennessee Valley on Friday night will settle southeastward
towards the Carolina coast by Sunday evening. Below climo highs
are expected on Saturday as low level flow veers from northerly to
northeasterly, and decoupling winds at inland locations on
Saturday evening could result in frosty conditions inland by early
Sunday morning. Onshore winds will allow inland highs to recover
back towards climatology on Sunday, followed by another warming
trend early next week. A decaying frontal boundary entering the
southeastern states could develop a few showers by late Tuesday
[Through 00Z Thursday]
VFR cigs expected through the late evening, then increasing chances
for showers and potential isolated storms from the west after
midnight. Most of the showers will be along and north of I-10
through 12z Wed. Cigs expected to trend to MVFR and then IFR for
TAFS late tonight with best chances of IFR for GNV, VQQ, JAX, and
SSI by the 09z-13z time frame. LIFR cig possible at GNV but
confidence is currently low on this potential. Some gradual
improvement in cigs possible by 15z-18z, but could trend back
down in the late aftn. However, more persistent low cigs likely
around SSI all day. Best chance of showers and storms Wednesday
will be north of GNV-JAX line. Some of the storms could be
locally strong to severe. Winds will be southwest to south
tonight aob 10 kt, then increase again on Wednesday morning.
A cold front moving through the southeastern states late this
afternoon will cross the Georgia waters on Wednesday morning,
with a few strong thunderstorms possible for the waters north of
St. Augustine. Small Craft should continue to Exercise Caution
offshore through Wednesday evening offshore, where sustained winds
of 15-20 knots and seas of 4-6 feet will prevail. The cold front
will push over the northeast Florida waters Wednesday night,
followed by a brief surge of northeasterly winds through early
Thursday. Meanwhile, low pressure developing along the upper Texas
coast Wednesday morning will move east-northeastward along the
I-10 corridor on Wednesday night and Thursday, with a strong cold
front accompanied by strengthening southwesterly winds and strong
to severe thunderstorms crossing our local waters on Thursday
afternoon and evening. Low pressure will strengthen as it
accelerates northeastward off the U.S. eastern seaboard on Friday,
with strong northerly winds expected through Saturday. Small Craft
Advisory conditions will overspread our local waters Friday
afternoon and evening, with conditions possibly improving to
Caution levels near shore by Saturday afternoon. Winds will
become onshore by Saturday evening with gradually decreasing
speeds, allowing seas to gradually subside by late in the weekend.
Conditions may improve back to Caution levels offshore by Sunday.
Breezy south-southwesterly surface and transport winds will
continue for locations south of Interstate 10 on Wednesday,
while low daytime dispersion values are expected throughout
southeast Georgia on Wednesday and Thursday. Rainfall amounts of 3
to 5 inches with locally higher totals will be possible over
portions of inland southeast Georgia Wednesday through Thursday
afternoon, where a Flash Flood Watch has been posted. Strong to
severe thunderstorms will be possible across northeast and north
central Florida on Thursday afternoon, where strong southwesterly
surface and transport winds will result in high dispersion values
Moderate flooding continues along portions of the Altamaha River,
with water levels continuing to fall at Charlotteville, Baxley
and Doctortown. Water levels have crested at Everett City. Minor
flooding continues along portions of the Satilla River basin.
Rainfall this week at upstream locations may exceed 4-6 inches,
which may result in substantial rises beginning during the
upcoming weekend. Local interests should closely monitor the
latest official forecasts which will be further refined as the
.PRELIMINARY POINT TEMPS/POPS...
AMG 64 69 55 64 45 / 70 80 70 90 10
SSI 63 71 58 69 48 / 60 70 50 90 40
JAX 65 82 61 80 50 / 20 40 30 70 50
SGJ 66 82 63 79 54 / 10 20 10 60 60
GNV 65 84 66 81 51 / 10 10 20 70 40
OCF 64 84 66 83 54 / 10 10 10 60 50
GA...Flash Flood Watch from 7 AM EST Wednesday through Thursday
evening for Appling-Atkinson-Bacon-Coffee-Jeff Davis-
Area Forecast Discussion
National Weather Service North Platte NE
530 PM CST Tue Mar 3 2020
.SHORT TERM...(This evening through Wednesday night)
Issued at 240 PM CST Tue Mar 3 2020
Forecast concerns in the near-term revolve around elevated fire
weather conditions Wednesday afternoon across portions of western
Nebraska. A bit of a chaotic start to the forecast period as the
local area is caught between a quickly southward diving clipper-like
system and more stout h5 cut-off trough along the southern
International border. The latter of these features will remain well
south of the area but the approaching disturbance currently over the
western Dakotas will encroach on the north central Nebraska counties
this afternoon and evening. This system will be bringing a pocket of
modest moisture with it and thus have some Slight Chance to Chance
PoPs for areas along and east of a Springview to Bartlett line.
Forecast soundings, most notably the RAP and HRRR, indicate
substantial dry air in the low levels, limiting the potential
altogether as this wave moves through. Colder air aloft within the
wave will produce some modest lapse rates and potentially enough
elevated instability to yield some isolated thunder. Thinking
potential for this too low at the moment so left out of the
forecast. Further south and west, more removed from the greatest
source of lift, dry air should limit precipitation to nothing more
than sprinkles. All activity will clear the area by late tonight.
Modest cool front will pass through tonight, preventing boundary
layer from totally decoupling across the area. Expect lows generally
in the 20s to low 30s further east.
Wednesday will see us add a few more degrees to the daytime highs.
As a surface trough passes through the area, surface winds will be
on the increase out of the southwest helping to usher in warm air.
Temperatures at h85 will approach the 8 to 12 degree C range, or
near the 90% moving average for LBF upper air data. Nearly
unidirectional surface to h85 winds will also promote momentum
transfer of strong gusts to the surface. With little in the way of
cloud cover, should see efficient mixing of the boundary layer
helping to mix those gusts to the surface. These types of setups
tend to favor temperatures warmer than guidance usually indicates
and so went with the warmest guidance plus a degree or two for
daytime highs. This covers most the area in the upper 50s to 60s, or
values that are 15 to 20 degrees above normal for early March.
Believe wind gusts will reach as high as 30 to 35 mph as well. With
all these conditions and collaboration with neighbors, decided to
expand and update the Fire Weather Watch to a Red Flag Warning from
noon to 6pm CST for much of the Sandhills into southwest Nebraska. A
second cool front will move through the area mainly during the
evening hours Wednesday and with strong pressure rises behind this
boundary, will see strong winds continue into the evening hours and
limit overnight recovery of humidity. With these strong winds, did
increase Thursday morning lows slightly but expecting values to
still fall into the 20s and 30s.
.LONG TERM...(Thursday through Tuesday)
Issued at 240 PM CST Tue Mar 3 2020
Beginning 12z Thursday. Slightly cooler temperatures are expected
for the daytime on Thursday as more Canadian are invades the area.
Temperatures will still be seasonable for early March, however, as
highs climb into the upper 40s to low 50s. Our dry weather looks to
continue into the start of the weekend as ridging develops across
the Rockies and mid-level heights rise through Saturday. Ridge axis
looks to settle in by early Saturday. Temperatures will be on the
upward trend with widespread 70s expected by Saturday. Ridging will
begin to breakdown Saturday into Sunday as the next weather producer
moves onshore the west coast and onto the High Plains Sunday.
General NWP consensus is a modest surface low pressure system
develops across northern Nebraska during the day and quickly treks
east during the afternoon. At the surface, a well pronounced surface
cool-front will push through the area as surface high pressure
builds in over the upper Midwest. Some model guidance is slow to
develop the surface low, keeping the highest PoPs south and east of
the local area. Given some uncertainties, did decide to limit PoPs
to Chance for now with the hopes that NWP guidance can hone in on
more precise timing and strength of the system, thus allow
confidence to increase. What is more certain is that a cooldown is
expected for Monday and Tuesday with the increased cloud cover and
precipitation chances with highs closer to normal during this time.
Temperatures will then be quick to rebound beyond the middle of next
week as ridging looks to redevelop.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 530 PM CST Tue Mar 3 2020
Mainly VFR conditions are anticipated through the forecast period,
although a couple aviation weather concerns arise. Scattered mid
level clouds with a few light rain showers and gusty northwest
surface winds will dissipate shortly after sunset this evening.
However, low level wind shear conditions are possible are
overnight. A lull in the winds is expected around daybreak, then
speeds pick up again out of the southwest late in the morning.
Issued at 240 PM CST Tue Mar 3 2020
Elevated fire weather conditions are anticipated for the remainder
of Tuesday afternoon with elevated to critical fire weather
conditions expected Wednesday afternoon across much of western and
Daytime highs Wednesday will climb into the upper 50s and 60s,
which is 15 to 20 degrees above normal. Sunny skies will allow for
ample daytime mixing, yielding gusts in the 30 to 35 mph range
and humidity values in the 15-20% range for most locations along
and west of Highway 83, with localized areas potentially seeing
lower. Fuels are reporting as ready to burn according to partners
and collaboration with neighboring offices led to the decision to
update and upgrade from a Fire Weather Watch to a Red Flag
Warning during the afternoon hours. As a surface front approaches
from the northwest by late afternoon/evening, winds will shift to
the northwest with gusts of 25 to 30 mph likely to continue
through the overnight hours. This will limit overnight humidity
recovery, with many locations seeing minimum humidity values
remain at or below 60%.
Red Flag Warning from noon CST /11 AM MST/ to 6 PM CST /5 PM
MST/ Wednesday for NEZ204-206-210-219.
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
805 PM CST Tue Mar 3 2020
805 PM CST
Guidance has trended slightly farther south with the focus for a
brief period of snow late tonight into Wednesday morning, in line
with observational trends across eastern SD and western IA this
evening. Have made a 20-40 mi southward shift with the axis of
higher snowfall, focusing roughly around and just north of the
I-88 corridor. A quick inch of slushy snow is possible primarily
in the 3- 7am window. Some concerns do exists that the precip
focuses into a very narrow 20-30 mile W to E corridor where totals
could be enhanced slightly. Will continue to monitor trends
tonight, but expect some minor localized impacts for the morning
commute, with air temps at or above freezing likely limiting the
potential for higher impacts.
315 PM CST
Another fast-moving clipper system will quickly return the
potential for precipitation to the region later tonight into
Wednesday morning, with some accumulating light snow possible
especially north of the I-80 corridor.
In the near term, mid-level trough associated with this morning`s
clipper was moving off to the east this afternoon. Mid-level cold
pool associated with this departing system, combined with a
deeply mixed boundary layer, has led to development of scattered
showers across eastern parts of the forecast area this afternoon.
RAP soundings/meso-analysis even depict 100-200 J/kg of SBCAPE,
which has produced some graupel as well as perhaps a rumble of
thunder from some of the deepest cores over northwest IN, which
are now moving east of the cwa. As this system exits stage right
this afternoon, clouds will decrease and blustery west winds
currently gusting to 35-40 mph will diminish.
Attention then quickly turns to another clipper system, noted in
afternoon water vapor imagery digging southeast out of eastern
Montana. This wave is progged to continue southeast tonight,
amplifying its associated mid-level trough across our area by
Wednesday morning. As this disturbance approaches the area later
tonight, backing low-level flow will induce a period of warm
advection and frontogenesis which will enhance an elevated
baroclinic zone across far northern IL/southern WI. This forcing
will develop beneath a region of fairly steep (7-7.5 C/km) mid
level lapse rates, leading to quick saturation and likely a period
of precipitation developing after midnight and persisting into
the early-mid morning hours of Wednesday. Guidance still shows
some minor differences with the details of the QPF axis, which
looks to be a relatively narrow west-east band across northern
IL/southern WI into northwest IN, but does focus the potential
across our cwa especially along and north of the I-80 corridor.
Thermal profiles generally support snow in those areas, with a
rain/snow mix farther south. Several things make for a slightly
lower-confidence snowfall amount forecast, including mild ground
conditions, the relatively short duration of snow, and also the
potential for narrow banded areas of heavier intensity snow.
Generally however, from the I-80 corridor northward am expecting
between a few tenths to perhaps an inch or so in some spots.
System exits quickly to the east Wednesday morning, with
sunshine, breezy northwest winds and above-freezing temperatures
expected to start melting snow quickly. Persistent cool advection
will limit highs to around 40/low 40s north, while southern parts
of the forecast area are expected to warm into the upper 40s
again. Quiet weather continues Wednesday night, as high pressure
315 PM CST
Wednesday night through Tuesday...
Another in a series of short wave disturbances along the polar
jet is progged to dig southeast from the northern Plains and
amplify across the Great Lakes region Thursday through Friday.
Associated surface low pressure reflection passes north of the
forecast area during the day Thursday, with it`s trailing cold
front pushing east across the cwa during the day. Forecast
soundings depict a fairly dry thermodynamic profile in advance of
the front, with relatively shallow saturation developing mainly
across northern/eastern parts of the cwa with the frontal passage
as cold advection cools the column. Timing of cold fropa during
the midday/early afternoon hours with temps in the 45-50 degree
range will result in p-type of rain/showers, with strong drying
then developing behind the front and shutting off precip. More
noticeably, windy conditions are again expected with south-
southwest winds gusting 30-35 mph ahead of the front in the
morning, then of 35+ mph from the west during the afternoon behind
the front. As the wave and surface low continue to move southeast
toward the upper Ohio Valley into Friday morning, a secondary
surface trough/cold front will move across the area, with gusty
winds turning more north-northwest. This will build larger waves
(in excess of 8 feet) into the Indiana shore of Lake Michigan, and
would likely result in a period lakeshore flooding during
Thursday night and persisting through Friday. Winds diminish
quickly later Friday, as surface high pressure builds in to the
area from the west. Friday looks to be the coolest day of the
entire forecast period, as strong cold advection limits highs to
near 40/low 40s in most areas.
Upper level high pressure ridging then develops across the
Midwest into the weekend, in the wake of the departing eastern
trough and downstream of troughing along the west coast. This will
produce a period of dry breezy and much warmer weather across the
region, as south flow becomes reestablished as surface high
pressure ridge drifts east of the area on Saturday. Persistent
warm advection pushes 925 mb temps to +5/6C Saturday, and to
around +10C on Sunday, which should support 50s for highs Saturday
and temps in the 60s for Sunday and our blended guidance is
appropriately a little warmer than EC and GFS MOS numbers,
especially for Sunday.
Precipitation potential then looks to increase as early as Sunday
night and more likely Monday, as medium-range guidance is in
decent agreement in bringing short wave energy out of the western
trough. Moisture feed from the western Gulf of Mexico also
increases into Monday, as deep south-southwesterly flow persists
ahead of an approaching cold frontal trough and surface low
pressure wave associated with the approaching short wave. Though
some timing differences exist between the different models with
the passage of the cold front, precip potential should peak
generally during the Monday-Monday night period. Depending on the
timing of the front, Monday has the potential to be another fairly
warm day, with highs in the 50s to near 60 east of the front.
Upper level flow is then progged to flatten across the region
Tuesday and Wednesday, which allows the front to become nearly
stationary somewhere south of the forecast area. ECMWF is stronger
with high pressure building across the area Tuesday, pushing the
front farther south. GFS and CMC are weaker with the ridge, and
are not quite as far south with the position of the front. Both
the GFS and CMC also spread precipitation back into the area by
Tuesday night, as they develop another stronger low which tracks
along the front into the region mid-week. For now, the main
message is for somewhat cooler weather by Tuesday, with a lower
but non-zero potential for additional rainfall.
For the 00Z TAFs...
Main change for this forcast package was a tweak in how snowfall
is handled for Wednesday morning. This may not be the correct
tweak...but the idea was to slide the start just a bit
later, include SN as prevailing with MVFR cigs and vsbys, then
include lower conditions in a short 2hr tempo group around the
time when the peak activity is expected. Overall this brief period
of light snow, probably mixed at times with rain, is not expected
to pose significant impacts. Any minor accumulations would likely
be on grassy areas rather than roads and runways, and that should
quickly melt as the day warms into the 40s.
Otherwise, gusty west winds diminish tonight and turn
southwesterly, then veer northwesterly again during the morning
after the snow passes.
LM...Small Craft Advisory...nearshore waters
until midnight Wednesday.
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Area Forecast Discussion
National Weather Service Pocatello ID
144 PM MST Tue Mar 3 2020
.SHORT TERM...Tonight through Thursday night.
Expect light snow and freezing drizzle in the eastern highlands
through Wednesday. Could see an additional inch or two in the
Island Park area with some potential for light freezing drizzle
mixed in. Temperatures are above freezing so could see some travel
issues as temperatures drop below freezing after sunset. Remainder
of the region will be dry through Thursday night with warm
temperatures. Expect well above normal temperatures continuing
through the week with temperatures in the Eastern Magic Valley and
Lower Snake Plain approaching 60 by Thursday. Expect 15 to 20 mph
winds Wednesday in the Eastern Magic Valley and Snake Plain from
Burley through Pocatello. Winds should be lighter on Thursday.
.LONG TERM...FRIDAY THROUGH NEXT TUESDAY...
Few changes were made in the long-term portion of the forecast.
Confidence remains highest Fri, as high pressure will provide dry
and warm conditions especially across the Magic Valley, lower Snake
Plain, and srn highlands where highs may reach the mid 50s to lower
60s! Our next trough of low pressure remains on tap for the weekend,
spreading snow into the Central Mntns Sat morning, and then
predominantly rain across the rest of the region Sat afternoon. Snow
levels will be running 6,000 to 6,500 feet. Precip trends toward all
snow late Sat night/Sun with snow levels falling toward 4,500 feet.
Some model differences remain in the strength of the cold front Sun
AM. An early look at storm total snow accumulations suggests an inch
or less below about 6,000 feet where rain will dominate for the
first half of the event, and generally 1-6 inches as you go up in
elevation with localized higher amounts above the passes. We`re
getting into the time of year when the sun angle and slightly warmer
ground/pavement temps may help us as well as far as reducing
impacts. At this time, the area that is forecast to see
precipitation sticking around long enough by the time the colder air
arrives is the eastern highlands and Bear Lake areas -- and these
areas have the highest accumulating snow potential Sun. Slightly
cooler weather with predominantly mntn snow showers remain Mon/Tues
as a secondary trough swings through. - KSmith
Generally VFR cigs/vsbys are expected. At KIDA, there is some
suggestion in the guidance that the lower atmosphere may be moist
enough to allow some low stratus to develop early Wed morning, and
we did go ahead and include this in their TAF starting at 10z,
although confidence is a bit low. The HRRR is advertising fog
development as well near the terminal, but leaned away from this as
winds may remain 5-8 knots which generally is a little high for fog.
We will watch trends closely. At KDIJ, we also broadbrushed some
VCSH throughout the TAF period (which would be snow), but confidence
was not high enough in snow getting into the terminal to upgrade
beyond VCSH. Snow showers may also be light enough to keep vsbys
from falling below 6SM. MVFR cigs are possible. - KSmith