A joint service of the UK Ag Weather Center and the National Weather Service.
day followed by the potential for severe weather in the evening and
Synoptically, a couple of things are taking place. First, we've got
upper level ridging over the 4-corners region that has persisted for
several days already, leading to hot conditions across the South
Central and Southwestern US. NAEFs highlights the geopotential
heights in this ridge as being in the 99th percentile for this time
of year. Second, a very strong low pressure system slides
southeastward through the Northern Plains and into the Midwestern
States. NAEFs picks this up as having minimum all time heights at
850mb and a minimum MSLP. In other words, an unusually strong ridge
is place across the Southwest as a highly anomalous low dips into
the Midwest. This contrast between these two systems unsurprisingly
generates an anomalously strong jet, which at 500mb, is being shown
near the max climatologically. Basically, this is an unusual pattern
Let's begin with the heat:
Low level ridging at 850mb is centered over Louisiana early
Friday. This will lead to subsidence and an overall suppression of
cloud cover and convection during the day, allowing Central AL to
heat up into the low to mid 90s, with the warmest temps in the
western and southwestern Counties. Surface winds are forecast to
be nearly due south, which will bring in quite a bit of moisture,
helping dewpoints increase to the mid 70s. The NAM even brings in
a narrow corridor of upper 70s dewpoints right along the AL/MS
state line, further increasing the heat indices in that area. A
heat advisory will be in place for the western and southern
counties of Central AL from noon to 7pm when heat indices will
likely exceed 105 degrees.
The severe threat will primarily be in the evening and into the
overnight hours Saturday morning. A shortwave slides through the
strong upper level trough and pushes southward through the Mid MS
Valley and into Western TN. Initially, models are having a hard time
resolving whether this will generate discreet supercells or a squall
line/MCS feature in Western Kentucky and into TN. Depending on which
convective-allowing model you look at and what run of that model,
you might get one solution or the other. Regardless, of the initial
mode, CAMs generally agree that as the event begins to our north.
The system then becomes more of an MCS that dives southward into
North AL and continues into Central AL. The GFS and NMM have this
MCS focused along the AL/MS state line along the axis of higher
instability (4000-5000 J/kg CAPE), which would make sense based on
how MCS propagation should take place. The NAM and ECMWF generally
have a more eastward focus that pushes through eastern portions of
Central AL, but this solution seems less likely as it doesn't follow
the better instability. Finally, the ARW pushes the stronger MCS
feature more through Mississippi. I say all of that to essentially
lay out the uncertainty of the forecast and where the the potential
MCS will move because it will highly depend on where storms initiate
upstream. The current forecast has the best chance for impacts in
the northwestern counties, highlighted in an enhanced risk. This is
based on where the environment is most conducive to support strong
to severe storms as the shortwave forcing moves through. Threat
wise, the biggest concern will damaging winds. Models generally
agree that as storms reach Central AL, the mode should be more of an
MCS-type event rather than discreet cells. Abundant shear is in
place to support rotating updrafts, but I'm not sure we'll see
storms develop out ahead of the MCS cluster, which would usually
lead to tornado concerns. I won't rule out the possibility of an
isolated tornado or two if a discreet storm can get going, but
confidence is very low, so will continue mention of damaging winds
as the main threat for this event.
By Saturday morning, the initial shortwave has pushed south of our
area and the upper level jet begins to nose into Central AL. Models
pick up on another shortwave developing Saturday afternoon in
Northeastern AL/Northern GA and pushing southward, which could set
off another MCS that pushes through our Northeastern and Eastern
counties. The placement of that shortwave will determine if any of
our area sees the chance for severe storms Saturday. Right now, I
can't rule out a damaging wind threat for our far eastern portions,
but I believe the best chances will be further east into Georgia.
Therefore, I will continue mention of severe weather Saturday
afternoon/evening, but keep it generally east of the I-65 corridor.
After this second shortwave pushes through late Saturday evening
into the overnight hours, we should see improving conditions across
Central AL with the best rain/storm chances ending before midnight
Sunday through Thursday.
The main upper low, currently associated with the weather in the
short term, will slowly slide southward on Sunday and Monday. As it
slides south, it will weaken as well. This low will then park over
the Southeast for the rest of the week. There are some model
disagreement with the exact track and overall timing, but the
pattern remains similar, so confidence is high that we will see
above normal rain chances for much of the next work week. The Euro
places the center of the low over northern GA/AL Monday afternoon
and keeps it generally in the same location through Wednesday. After
that the energy gets shifted to the south along the coast through
the end of the week. Meanwhile the GFS bring the center of the low
more into northern AL/MS by Tuesday morning. The low spins across
central AL before it weakens into more of an upper trough. Either
scenario would keep higher than normal precipitation chances for the
area, with the only uncertainty being where to put the highest
chances. As for temperatures, will trend temperatures in the upper
80s to near 90 for now and adjust downward if needed as we get
closer and confidence of the path is higher. The good news is that
the lows should be cooler, with the lower dewpoints, so the
oppressive heat will not be as much of an issue.
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
500 AM CDT FRI JUL 20 2018
CITY SKY/WX TMP DP RH WIND PRES REMARKS
BIRMINGHAM MOCLDY 73 70 90 E5 29.98S
MONTGOMERY CLOUDY 75 73 93 NE7 29.94R
SHELBY CO ARPT CLOUDY 72 70 93 CALM 29.95F
MAXWELL AFB CLOUDY 74 71 91 NE5 29.93R
GREENVILLE FOG 72 69 90 NE3 29.93R VSB 1/2
SELMA FOG 73 73 100 NE5 29.92R VSB 1
PRATTVILLE CLOUDY 73 73 98 NE6 29.94R
BESSEMER FAIR 71 71 100 E6 29.96F
TALLADEGA FAIR 71 70 98 CALM 29.98R
PELL CITY SUNNY 70 70 100 CALM 29.97F
MARION FOG 72 72 100 CALM 29.91S VSB 1/4
SYLACAUGA FAIR N/A N/A N/A CALM 29.97R
Current Agricultural Weather Conditions in Alabama
Based on observations at 500am CDT, Friday July 20, 2018
Across Alabama...temperatures are near 71 degrees north, near 73 degrees central, and near 74 degrees south. Current sky conditions are fair north, mostly cloudy central, and fair south. In the north, relative humidity is near 93%, and the dew point is near 69 degrees. In the central part of the state, relative humidity is near 90%, and the dew point is near 70 degrees. In the south, relative humidity is near 97%, and the dew point is near 73 degrees. The livestock heat stress category is no stress north, no stress central, and no stress south. Winds are from the southeast at 5 mph north, where conditions are favorable for spraying. Winds are from the east at 5 mph 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 77 degrees at Brookely Field. The lowest temperature is 69 degrees at Gadsden.
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
429 AM CDT Fri Jul 20 2018
DAY ONE Today and Tonight.
The combination of high temperatures and humidity will push heat
index values to around 105 degrees on Friday afternoon and again
Saturday afternoon. This will occur generally west of a line from
Eufaula to Alabaster to Hamilton.
Severe thunderstorms will be possible across all of Central Alabama
Friday night into early Saturday morning. A line of storms with
damaging winds may enter our northern counties as early as 7 PM
Friday and continue southward through 4 AM Saturday. Currently the
highest threat area appears to be along and northwest of Interstate
59, where widespread wind damage is possible.
DAYS TWO THROUGH SEVEN Saturday through Thursday.
Severe storms may develop again on Saturday afternoon and evening
along and east of interstate 65. These storms may be isolated to
scattered in nature and capable of producing damaging winds, quarter
size hail, and perhaps a tornado. Currently, forecast confidence in
this scenario is low.
SPOTTER INFORMATION STATEMENT
Activation of storm spotters and emergency management may be needed
on Friday night and Saturday.
NWS Severe Weather Map , Convective Outlook
7-Day Forecast For COOSA County, Alabama
530 AM CDT Fri Jul 20 2018
Partly cloudy with a 20 percent chance of thunderstorms.
Highs in the lower 90s. Light winds becoming north around 5 mph
in the afternoon.
TONIGHT Partly cloudy in the evening then becoming mostly
cloudy. A 50 percent chance of thunderstorms. Lows in the lower
70s. Light winds becoming southwest around 5 mph after midnight.
SATURDAY Partly cloudy with a 50 percent chance of
thunderstorms. Highs in the lower 90s. West winds 5 to 10 mph.
SATURDAY NIGHT Mostly cloudy with chance of thunderstorms in
the evening, then partly cloudy with slight chance of
thunderstorms after midnight. Lows in the lower 70s. West winds
5 to 10 mph. Chance of rain 50 percent.
SUNDAY Partly cloudy with a 30 percent chance of
thunderstorms. Highs in the lower 90s. West winds 5 to 10 mph.
SUNDAY NIGHT Mostly cloudy with a 20 percent chance of
thunderstorms. Lows in the lower 70s.
MONDAY Partly cloudy. Slight chance of thunderstorms in the
morning, then chance of thunderstorms in the afternoon. Highs
around 90. Chance of rain 50 percent.
MONDAY NIGHT Mostly cloudy with a 20 percent chance of
thunderstorms. Lows around 70.
TUESDAY Partly cloudy with a 40 percent chance of
thunderstorms. Highs in the upper 80s.
TUESDAY NIGHT Mostly cloudy with a 30 percent chance of
thunderstorms. Lows in the lower 70s.
WEDNESDAY Partly cloudy with a 50 percent chance of
thunderstorms. Highs around 90.
WEDNESDAY NIGHT Mostly cloudy with a 30 percent chance of
thunderstorms. Lows in the lower 70s.
THURSDAY Thunderstorms likely. Highs in the upper 80s. Chance
of rain 60 percent.
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
JUL 25-29 JUL 27-AUG 2 JUL JUL-SEP
----------- ----------- -------- ---------
Temperature: Below Below Above Above
Precipitation: Above Above Normal Normal
.... Medium and long range outlooks provided by NCEP/K. Thomas Priddy
5 Day Rainfall Forecast,
6 to 10 Day ,
8 to 14 Day ,
Friday July 20, 2018 the 201th Day of Year
Distance 0.999716 AU
Rise 06:53 EDT Set 20:56 EDT
Transit Meridian 13:54 EDT
Civil Twilight Begins 06:26 EDT Ends 21:23 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
JULY 20TH...HISTORIC WEATHER EVENTS
The temperature at Washington D.C. soared to an all-time record of 106
degrees. The next day Millsboro reached 110 degrees to set a record for the
state of Delaware. July 1930 was one of the hottest and driest summers in
the U.S., particularly in the Missouri Valley where severe drought
conditions developed. Toward the end of the month state records were set
for Kentucky with 114 degrees, and Mississippi with 115 degrees. (David
The temperature at Keokuk IA soared to 118 degrees to establish a state
record. (The Weather Channel)
Twenty-two inches of hail reportedly fell northeast of Dickinson ND. (The
The temperature at Charleston SC hit 104 degrees for the second day in a
row to tie their all-time record high. (The Weather Channel)
Thunderstorms produced severe weather across Minnesota, Wisconsin and
Michigan. Thunderstorms produced wind gusts to 87 mph at Mosinee WI, and
strong thunderstorm winds capsized twenty-six boats on Grand Traverse Bay
drowning two women. Thunderstorms produced nine inches of rain at Shakopee
MN, with 7.83 inches reported in six hours at Chaska MN. Thunderstorms in
north central Nebraska produced hail as large as golf balls in southwestern
Cherry County, which accumulated to a depth of 12 inches. (The National
Weather Summary) (Storm Data)
The temperature at Redding CA soared to an all-time record high of 118
degrees. Showers and thunderstorms produced much needed rains from New
England to southern Texas. Salem IN was deluged with 7.2 inches of rain
resulting in flash flooding. (The National Weather Summary)
Showers and thunderstorms in the Middle Atlantic Coast Region soaked
Wilmington DE with 2.28 inches of rain, pushing their total for the period
May through July past the previous record of 22.43 inches. Heavy rain over
that three month period virtually wiped out a 16.82 inch deficit which had
been building since drought conditions began in 1985. Thunderstorms in
central Indiana deluged Lebanon with 6.50 inches of rain in twelve hours,
and thunderstorms over Florida produced wind gusts to 84 mph at Flagler
Beach. (The National Weather Summary) (Storm Data)
Ag Weather Center, Department of Biosystems & Agricultural Engineering, University of Kentucky