A joint service of the UK Ag Weather Center and the National Weather Service.
An area of rain with embedded thunderstorms is moving across
Central Alabama this afternoon. This activity is tracking along a
stalled frontal boundary that will lift back to the north
overnight. Within the warm, moist airmass south of the now lifting
warm front, scattered to numerous showers are possible. This
activity is not expected to be strong or severe. Temperatures
tonight will be rather muggy, with lows in the mid 50s north to
mid 60s south.
Looking toward tomorrow, not much has changed from what was
discussed in the previous long term discussion. There remains
some uncertainty regarding the extent of rain coverage early
Monday morning (either just to our north or along the Gulf coast),
and how that affects the airmass through the morning hours.
There is good model agreement regarding the development of a
broken line of storms occurring just to our west or over NW
Central Alabama by late afternoon, and pushing eastward through
the evening hours. The expected impacts and coverage areas have
not changed. We made slight adjustment to the timing this
afternoon and updated graphics will be out shortly. We will
continue to refine timing tonight and tomorrow morning.
Monday through Saturday.
Confidence that the area will see significant severe
thunderstorms continues to increase for Monday, as models are
coming into better agreement on the synoptic pattern. As usual,
there are some mesoscale details that will determine the exact
timing and type of threat. Models are coming into better agreement
with the timing and placement of a compact upper low that will
eject out of the western CONUS trough into northeast New Mexico
this afternoon. It will deamplify slightly as it moves eastward to
the TN/KY border region as it approaches confluent flow
associated with the eastern Canadian trough, but still remain a
potent system with strong height falls and a neutral tilt. A
strong WSW mid and upper level jet max (~90kt at 250 mb, ~70 kts
at 500 mb, ~65 kts at 700mb) will be located to its south, which
will move over Central Alabama. A ~35-40kt southwesterly LLJ at
850mb will accompany a 998mb surface low moving across Tennessee.
This surface low will be close to steady-state in strength during
the afternoon, before effectively splitting into two pieces as it
encounters the southern Appalachians Monday night. A trailing
pre-frontal trough/dry line feature will move into West Alabama
from Mississippi Monday afternoon.
Starting off Monday morning, not expecting to see a whole lot of
activity on the radar due to dry air and capping aloft associated
with an elevated mixed layer and weak shortwave ridging aloft.
Showers and storms associated with Sunday night's shortwave will
likely be mainly north and east of the forecast area. But with
low-level isentropic lift there could be some light showers, and
perhaps some isolated leftover thunderstorms from Sunday night.
There will probably be some low stratus as well. One possible
wrench in the forecast is a secondary LLJ in the NAM and some of
the global models that these models show causing an increase in
moisture and isentropic lift across southeast Alabama and the
Florida panhandle during the late morning with associated
precipitation. This could affect destabilization in the afternoon,
or if accompanied by thunderstorms could result in an isolated
severe threat developing earlier than expected in the far
southeast counties. However, the CAMs are much further east with
this activity, closer to the Florida Big Bend and South Georgia.
These may have a better handle on the situation if they are
handling Sunday night's preceding convection better than the
global models. Also, the models that show this feature all still
indicate very strong instability developing by Monday afternoon
across the entire area, so it may not matter much.
Most of the day on Monday may be a nice warm sunny spring day, but
folks should not let their guard down. This daytime heating will
allow CAPE values of 2000 to 3000 J/kg to develop due to
temperatures in the upper 70s to low 80s. The 00Z NAM did show an
unlikely situation where low stratus clouds never mix out all and
surface temperatures remaining much cooler, preventing convective
initiation. But this seemed extremely unlikely given the strong
southwesterly flow and dry air aloft. The 6Z NAM has already
trended back in line with strong daytime heating, but is slower
with the storms than the guidance consensus as is its typical bias.
The WRF-ARW, NSSL WRF, and WRF-NMM were in good agreement in
explosive thunderstorm development along the pre-frontal trough/
dry line as upper- level forcing arrives, between about 4PM and
7PM roughly along/northwest of the I-59 corridor. These storms
will probably initiate right over Central Alabama rather than
moving in from Mississippi. The convective mode will be a broken
line of semi- discrete supercells, due to westerly 55-60kt 0-6 km
bulk shear vectors orthogonal to the initiating boundary. Dry air
aloft/capping will likely inhibit storms from developing ahead of
this line, except perhaps in the far northeast counties, so
confidence in timing out this line is increasing. The environment
will be very favorable for large to very large hail to develop due
to the rotating updrafts and fat CAPE profiles more typical of
the Plains than the Southeast, with significant hail >2" diameter
appearing likely with some of the storms. Damaging winds will also
occur with the hail-enhanced downdrafts due to high DCAPE.
Concerning the tornado potential, the 850mb-925mb flow will be a
bit veered to the southwest and not extremely strong. This veered
flow will probably mix down to the surface; the NAM is more backed
but does not seem to be mixing the boundary layer properly as
mentioned related to the spurious looking low stratus mentioned
above. The surface low will also not be deepening, so isallobaric
flow will not be a factor. So near-surface streamwise vorticity
does not appear to be enhanced, with the critical angles between
the 0-0.5km shear vector and 0-0.5km storm-relative flow being
mainly well below the optimal 90 degree angle. The presence of
strong rotating updrafts in a high CAPE environment with around
200m2/s2 0-1km SRH can compensate somewhat for the less than
favorable wind directions. Therefore, think there is a threat for
a couple to maybe a few tornadoes, especially the further north
you go closer to the surface low, and especially right around/just
after sunset when the nocturnal LLJ begins to strengthen. One
potential area of concern for strong tornadoes, however, is the
far northeast counties where flow could remain a bit more backed,
near a lingering wedge front over north Georgia. Confidence
remains too low to mention the potential for a strong/significant
tornado in the HWO/graphics, but we will continue to monitor
closely as we get closer. Either way, these will be dangerous
storms that everyone needs to pay attention to. Did opt to lower
some of the far southern counties from an enhanced risk to a
slight risk in our local forecast. There is still certainly a
severe threat in those areas that people need to be aware of, with
plenty of instability present, but storm coverage is expected to
be more isolated down there due to weaker forcing.
Looking briefly at the extended, another shortwave will bring a
chance of showers Tuesday, but nothing severe is expected. Lows
may drop to near freezing Wednesday night. Models are not in good
agreement with a shortwave/possible frontal passage in the
Friday/Saturday timeframe, but generally indicate a lack of
significant moisture return ahead of it.
Alabama Forecast Discussion (NWS)
National Ag. Weather Outlook, International Ag. Weather Summary
Current Surface Map,
[2nd Source TWC]
Click here for UKAWC Point Agricultural, Lawn & Garden Forecast/Outlook in case of corrupt tables.
Regional Hourly Observations For COOSA County
800 PM CDT SUN MAR 18 2018
CITY SKY/WX TMP DP RH WIND PRES REMARKS
BIRMINGHAM CLOUDY 66 54 65 CALM 29.86F
MONTGOMERY CLOUDY 68 67 96 N6 29.83F FOG
SHELBY CO ARPT CLOUDY 62 59 90 CALM 29.85S
MAXWELL AFB CLOUDY 65 63 94 NE10 29.82F
GREENVILLE CLOUDY 66 63 90 CALM 29.82S
SELMA CLOUDY 66 64 94 CALM 29.82F
PRATTVILLE CLOUDY 65 65 100 NE3 29.83F
BESSEMER CLOUDY 61 58 90 CALM 29.85F
TALLADEGA CLOUDY 66 53 61 SW5 29.85F
PELL CITY CLEAR 63 55 77 CALM 29.85S
MARION CLOUDY 65 65 100 S6 29.82S FOG
SYLACAUGA CLOUDY 62 62 100 CALM 29.85F
Current Agricultural Weather Conditions in Alabama
Based on observations at 800pm CDT, Sunday March 18, 2018
Across Alabama...temperatures are near 57 degrees north, near 66 degrees central, and near 68 degrees south. Current sky conditions are mostly cloudy north, cloudy central, and mostly cloudy south. In the north, relative humidity is near 77%, and the dew point is near 50 degrees. In the central part of the state, relative humidity is near 65%, and the dew point is near 54 degrees. In the south, relative humidity is near 90%, and the dew point is near 65 degrees. Winds are from the north at 5 mph north, where conditions are favorable for spraying. Winds are calm central, where conditions are favorable for spraying. Winds are calm south, where conditions are favorable for spraying. Based on current available observations, the highest temperature is 68 degrees at Montgomery, Mobile, Evergreen, and Brookely Field. The lowest temperature is 57 degrees at Decatur.
Current NOWCAST not available:
Nowcasts are not issued routinely during fair weather. Only when
precipitation or other significant weather is occuring in this county will these
forecasts be issued. Currently, there is no short term forecast in effect.
U.S. Radar Map,
All NWS Radars (In near-real time),
Current Livestock Heat Stress Index (LSI),
Current Wind Chill Map
Hazardous Weather Outlook For COOSA County, AL
650 PM CDT Sun Mar 18 2018
DAY ONE Through Tonight.
No hazardous weather is anticipated overnight.
DAYS TWO THROUGH SEVEN Monday through Saturday.
Severe storms are likely across all of Central Alabama on Monday,
mainly between 4 PM and midnight. These storms will be capable of
producing tornadoes, large hail up to the size of tennis balls, and
wind gusts to 70 mph. At this time, the threat appears to be
slightly higher north of the US Highway 80 and Interstate 85
corridor, but all of Central Alabama should remain aware of the
severe thunderstorm potential on Monday and take the appropriate
precautionary measures. There is a possibility that this risk may
need to be upgraded, so keep up to date on the forecast heading into
Cooler air moving in behind the system will result in the potential
for lows at or below freezing across parts of north central Alabama
SPOTTER INFORMATION STATEMENT
Activation of storm spotters and emergency management may be needed
into this evening. Activation will be needed Monday afternoon and
NWS Severe Weather Map , Convective Outlook
7-Day Forecast For COOSA County, Alabama
802 PM CDT Sun Mar 18 2018
Rain showers and chance of thunderstorms in the
evening, then rain showers likely and chance of thunderstorms
after midnight. Lows in the upper 50s. East winds around 5 mph.
Chance of rain 80 percent.
MONDAY Cloudy in the morning then becoming partly cloudy. A
50 percent chance of thunderstorms. Highs in the mid 70s. South
winds 5 to 10 mph.
MONDAY NIGHT Mostly cloudy. Thunderstorms in the evening, then
chance of thunderstorms after midnight. Some thunderstorms may be
severe in the evening. Lows in the mid 50s. Southwest winds 5 to
10 mph. Chance of rain 80 percent.
TUESDAY Partly cloudy in the morning then becoming cloudy. A
40 percent chance of rain showers. Highs in the upper 60s. West
winds 10 to 15 mph.
TUESDAY NIGHT Colder. Mostly cloudy. A 20 percent chance of
rain showers in the evening. Lows in the upper 30s. Northwest
winds 10 to 15 mph.
WEDNESDAY Mostly sunny. Highs in the lower 60s.
WEDNESDAY NIGHT Mostly clear. Lows in the mid 30s.
THURSDAY Sunny. Highs in the lower 60s.
THURSDAY NIGHT Mostly clear. Lows around 40.
FRIDAY Partly cloudy. Highs in the upper 60s.
FRIDAY NIGHT Mostly cloudy. Lows in the upper 40s.
SATURDAY Partly cloudy with a 20 percent chance of
thunderstorms. Highs in the lower 70s.
SATURDAY NIGHT Mostly cloudy with chance of rain showers and
slight chance of thunderstorms. Lows in the upper 50s. Chance of
rain 30 percent.
SUNDAY Mostly cloudy with a 20 percent chance of
thunderstorms. Highs in the mid 70s.
12-48 Hr Surface Forecast Maps,
TWC 4-Panel Surface Forecast,
Day 1 Precip,
Day 2 Precip,
Days 1-5 Precip,
Severe Weather Pot.-Day 1,
Medium & Long Range Outlook For Alabama
6 TO 10 DAY 8 TO 14 DAY 30 DAY 90 DAY
MAR 24-28 MAR 26-APR 1 MAR MAR-MAY
----------- ----------- -------- ---------
Temperature: Above Above Normal Above
Precipitation: Above Above Above Normal
.... Medium and long range outlooks provided by NCEP/K. Thomas Priddy
5 Day Rainfall Forecast,
6 to 10 Day ,
8 to 14 Day ,
Sunday March 18, 2018 the 77th Day of Year
Distance 0.999721 AU
Rise 06:54 EDT Set 18:59 EDT
Transit Meridian 12:55 EDT
Civil Twilight Begins 06:30 EDT Ends 19:22 EDT
Calculations made for central point in the state.
Time in ET -- and will vary due to location and
elevation -- Priddy
Historical Weather And Climate Facts For Today
HISTORIC WEATHER EVENTS
The great "Tri-State Tornado" occurred, the most deadly tornado in U.S.
history. The tornado claimed 695 lives (including 234 at Murphysboro IL and
148 at West Frankfort IL), and caused seventeen million dollars property
damage. It cut a swath of destruction 219 miles long and as much as a mile
wide from east central Missouri to southern Indiana between 1 PM and 4 PM.
The tornado leveled a school in West Frankfort IL, and picked up sixteen
students setting them down unharmed 150 yards away. Seven other tornadoes
claimed an additional 97 lives that day. (David Ludlum)
High winds accompanied a low pressure system from the Rocky Mountains to
the Great Lakes. Winds gusted to 100 mph at Hastings NE, and reached 115
mph at Hays KS. High winds caused two million dollars damage in Kansas.
Fire burned 50,000 forest acres in eastern Oklahoma. (17th-19th) (The
Ag Weather Center, Department of Biosystems & Agricultural Engineering, University of Kentucky