The Hazardous
Weather Outlook (HWO) text product is issued daily around 530
AM, and is updated as needed. The Graphical Hazardous
Weather Outlook product is issued shortly after the issuance of
the text product. The color key on the right side of each map
describes the color coding used in conveying a particular hazardous
weather threat. Text describing the hazardous weather threats
over the entire 7-Day period is displayed at the bottom of each
map.
Day
One Outlook
The Day One Outlook is valid until 6 AM the next
day (Day 2), and consists of five individual threat maps. The
following information provides explanations of the various categories
on each map:
Thunderstorms
The definition of a severe thunderstorm is a storm that produces winds of 58
mph or greater, and/or hail 3/4ths inch in diameter or greater, and/or tornadoes.
An explanation of shadings for the various counties follows:
- Purple�.......High Risk
of Severe Tstms (widespread coverage) Used for the
most dangerous events.
- Red��........Moderate Risk
of Severe Tstms (scattered coverage)
- Orange��..Slight Risk of
Severe Tstms (isolated coverage)
- Yellow��...Strong Tstms
(isolated to widespread coverage) (small hail and/or winds 40-57
mph)
- Light Pink�.NON-Severe Tstms
(isolated to widespread) (small hail and/or winds less than
40 mph.
Flooding
Flooding on this map refers to rises in water levels along smaller rivers and
streams (not the larger rivers) and in low lying or other flood prone areas.
Flash Flooding refers to rises in water levels in the same areas, but occurs
in a much shorter time frame, and therefore can be more life-threatening. Flash
Flooding may also occur due to a dam failure.
- Green���Flooding Possible
- A Flood or Flash Flood Watch will typically be in effect,
unless the flooding will only affect isolated areas. The flooding
can be short-lived (lasting 6 hours or less) or long-lived (lasting
a day or more).
- Light Blue�.Heavy Rain/Ponding
on Roads - Heavy rain may cause ponding of water on
roads and highways, and in low-lying and other flood-prone areas.
The flooding will affect isolated to widespread areas. These
events are usually short-lived (lasting 12 hours or less).
Wind & Fog
The Wind categories on this map refer to Non-thunderstorm winds.
- Red����..�Wind > 40 mph
- A High Wind Warning will typically be in effect.
- Orange���...Wind > 30 mph
- A Wind Advisory will typically be in effect.
- Light Orange�.Wind > 20
mph - A Lake Wind Advisory (for boaters) will typically
be in effect.
- Yellow..............Wind
< 20 mph � Gusts > 30 mph - A Lake Wind Advisory (for
boaters) will typically be in effect.
- Dark Blue��...Dense Fog
- A Dense Fog Advisory will typically be in effect when visibilities
are expected to be less than 1/4th mile, unless fog coverage
will only affect isolated areas.
- Light Blue��.Freezing Fog
- A Freezing Fog Advisory will typically be in effect when temperatures
will be less than 32 F and visibilities will be a few miles
or less, unless fog coverage will only affect isolated areas.
Temperature Extremes,
Frost / Freeze
The Heat Index categories on this map represent the combination of high temperatures
and humidities that can result in hazardous or even life-threatening conditions
if protective measures are not taken. The Wind Chill categories represent the
combination of cold temperatures and winds that can result in hazardous or even
life-threatening conditions if protective measures are not taken.
- Red����Heat Index > 110 F - An Excessive Heat
Warning may or may not be in effect, depending on minimum heat index temperatures
expected at night.
- Orange��..Heat Index > 105 F - A Heat Advisory
may or may not be in effect, depending on minimum heat index temperatures
expected at night.
- Dark Blue�..Freeze < 33 F - A Freeze Warning will
typically be in effect. Freezing temperatures may occur only in low-lying
and sheltered areas, or may be expected over the entire area. Frost may also
occur.
- Light Blue.�.Frost 33 to 36 F - A Frost Advisory
will typically be in effect. Frost may occur only in low-lying and sheltered
areas, or may be expected over the entire area.
- Dark Pink�..Wind Chill < -25 F - A Wind Chill
Warning will typically be in effect.
- Light Pink�.Wind Chill -10 F to -24 F - A Wind
Chill Advisory will typically be in effect.
Snow / Sleet / Ice
- Dark Blue�..Snow > 3 inches
- A Winter Storm Warning will typically be in effect.
- Light Blue�.Snow 1 to 3
inches - A Snow Advisory will typically be in effect.
- Gray���...Snow < 1 inch
- A Snow Advisory will usually not be in effect for this amount
of snowfall.
- Purple��....Sleet
- A Sleet Warning will typically be in effect if 1/2 inch or
more of sleet is expected. If a lesser amount is expected, a
Sleet Advisory may or may not be in effect.
- Dark Pink�..Mix of Snow/Sleet/Ice
- A Winter Storm Warning or Advisory will typically be in effect.
- Red���.....Ice Storm
- An Ice Storm Warning will typically be in effect.
- Orange�..�.Light to Moderate
Icing - A Freezing Rain Advisory will typically be
in effect.
Days
2-3 Outlook
The Days 2-3 Outlook is more general than the Day One Outlook,
and will be valid from 6 am the next day (Day 2) until 6 am on
Day 4. Eight potential weather hazard categories are listed in
order of importance, from top to bottom. If more than one hazard
is expected in a county, the most important hazard is plotted.
A hazard is only plotted if there is a potential for the issuance
of an Outlook, Watch, Warning or Advisory.
Days
4-7 Outlook
The Days 4-7 Outlook is even more general than the Days 2-3 Outlook,
and will be valid from 6 am on Day 4 until 6AM on Day 8. Five
potential weather hazard categories are listed in order of importance,
from top to bottom. If more than one hazard is possible in a county,
the most important hazard is plotted. A hazard is only plotted
if there is a potential for the issuance of an Outlook, Watch,
Warning or Advisory.