Winter Returns Across the Northern Tier; Record Warmth for the Southwest

A large high pressure system will usher in cold air for this first day of March across the northern Plains, Great Lakes, Northeast and mid-Atlantic. Some wintry precipitation may evolve across the mid-Mississippi Valley, Ohio Valley and mid-Atlantic through Monday. Meanwhile, record warmth will spread across the Southwest, southern Plains through early this week. Read More >

Louisiana and Southeast Texas
Fog Research and Modeling
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Individual Parameter Statistics
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Rainfall and moisture relationship to fog formation in Southwest Louisiana and Southeast Texas

*Rainfall within 36 hours*	*13 days (25.5 %)*
*Moisture advection*	*32 days (62.7 %)*
*Rain AND moisture advection*	*6 days (11.8 %)*
*Rain OR moisture advection*	*38 days (74.5 %)*
*No rain or moisture advection*	*13 days (25.5 %)*

For the fog days which showed no rain or moisture during a 12 hour period, the moisture flux occured the day or night before. The reason for fog not forming the previous night was that at least one or more other parameters were out of tolerance.

Wind relationship to fog formation in Southwest Louisiana and Southeast Texas

*Calm wind*	*13 days (25.5 %)*
*Light and variable wind*	*7 days (13.7 %)*
*Wind 0 - 5 knot*	*29 days (56.9 %)*
*Wind 6 - 12 knot*	*22 days (43.1 %)*
*Wind 0 - 12 knot*	*51 days (100 %)*

There was no fog reducing visibilities to 1/2 half mile or less with winds greater than 12 knots.

Temperature relationship to fog formation in Southwest Louisiana and Southeast Texas

Highest temperature with fog: 76 degrees Lowest temperature with fog: 31 degrees
*Temperature 71 - 76 degrees*	*5 days (9.6 %)*
*Temperature 61 - 70 degrees*	*23 days (44.2 %)*
*Temperature 51 - 60 degrees*	*12 days (23.1 %)*
*Temperature 41 - 50 degrees*	*10 days (19.2 %)*
*Temperature 31 - 40 degrees*	*2 days (3.8 %)*

The overnight low temperature increased an average of 5 degrees from the previous night for 32 fog days. The overnight low temperature decreased an average of 4 degrees from the previous night for 19 fog days.

Time of day (in CST)

*Radiation fog*	*Marine fog*	*Frontal fog*	*Advection fog*	*Total fog*
*0000->: 15 days*	*0000->: 16 days*	*0000->: 4 days*	*0000->: 5 days*	*0000->: 40 days*
*2100-0000: 4 days*	*2100-0000: 4 days*	*2100-0000: 2 days*	*2100-0000: 1 day*	*2100-0000: 11 days*

No fog set in before 2100 during the period of this study, but this has happened in other years.

Number of days each month

*July: 1*	*August: 0*	*September: 1*
*October: 7*	*November: 11*	*December: 6*
*January: 9*	*February: 5*	*March: 6*
*April: 5*	*May: 0*	*June: 0*

Months with 3 or more consecutive fog days: November, December, January and February.

Monthly types

July 1 radiation	September 1 radiation	October 6 radiation 1 marine
November 3 radiation 6 marine 1 advection 1 frontal	December 2 radiation 3 marine 1 frontal	January 3 radiation 4 marine 2 advection
February 1 radiation 2 marine 2 frontal	March 1 radiation 1 marine 2 advection 2 frontal	April 1 radiation 3 marine 1 advection

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Winter Returns Across the Northern Tier; Record Warmth for the Southwest

Research Studies