Winter (Dry) Season 2008-2009 Wrap-Up
for Northeast Florida and Southeast Georgia


The overall winter (dry) season of 2008-2009 for Northeast Florida and Southeast Georgia can be generalized by slightly cooler than normal temperatures, below normal precipitation and an above normal number of freeze events. The winter (dry) season for this study was determined to be the five month period from November 1st through March 31st. This is the period that the majority of freeze events occur across the forecast area. This climate summary is based on four different official climate sites across the region: Jacksonville International Airport (JAX) in Northeast Florida, Gainesville Regional Airport (GNV) in Northeast Florida, Bacon County Airport at Alma (AMG) in Southeast Georgia, and Brunswick McKinnon Airport at St Simons Island in Southeast Georgia. These four climate sites are a good summary for the region with 2 sites closer to the coast and 2 sites much further inland and represent a good cross section of the weather impacts in the forecast area.

The average temperatures across the forecast area during the winter season did take quite a roller coaster ride that is normally characterized by conditions dominated a weak La Nina episode in the Pacific Ocean. To start off the winter season, November will go down as one of the coldest on record with average temperatures from four to six degrees below normal.  JAX and GNV both ranked the third coldest on record in over a century of record keeping, while GNV's average minimum temperature of 44.4 degrees in the coldest ever. The month of December did an abrupt shift and the average temperature's were quite warm with departures some three to four degrees above normal.  Christmas of 2008 will go down as the warmest on record with JAX, AMG and SSI all setting record high temperatures for the date around 80 degrees.  The average temperatures in January tweaked backed toward normal will all sites within one degree either side of normal. February turned much colder once again with average temperatures two to four degrees below normal and a number of sites recording their coldest readings of the winter around 20 degrees. More spring like temperatures returned in March with the month finishing with near normal temperatures across the region.

For the entire season, the five month period averaged slightly below normal with departures of one to two degrees below normal. The interesting note for this past season is while average maximum temperatures were near normal, the lack of precipitation, dry soil moisture levels, and abundant clear skies at night were able to push the average minimum temperatures well below normal with GNV and JAX ranking fifth and seventh coldest on record, respectively.  The details of this season's temperatures are listed in Table 1.


Table 1

Nov-Mar Average Max Temp (F) (Departure)

Nov-Mar Average Min Temp (F) (Departure) (Rank)

Nov-Mar Average Temp (F) (Rank)

Departure from Normal

JAX

69.7 (+0.4)

44.1 (-2.1) (7)

56.9 (29)

-0.9

GNV

71.5 (+0.1)

43.9 (-4.3) (5)

57.7 (12)

-2.1

AMG

67.0 (+0.3)

41.8 (-2.8) (22)

54.4 (24)

-1.3

SSI

65.4 (+0.6)

47.4 (-0.3) (31)

56.4 (32)

+0.1

An alternative way to measure a winter season's temperature is by the number of freeze events at a given location. A freeze event is defined by the minimum temperature falling to 32 degrees or less on a certain calendar day. Freeze events are important in this region due to their impact on the agricultural industry, while hard freeze events with a minimum temperature of 25 degrees or less can cause extensive damages to crops and freeze pipes in houses. This season averaged 10 to 15 more freeze events than normal at inland locations such as JAX, GNV and AMG, while the one site directly on the coast, SSI was near normal.  Table 2 summarizes the freeze event data for this season as well as lists normal and extreme values for each of the four stations. The one thing that stands out is that this winter ranked so high in the number of freezes while still not seeing that many hard freeze events, this was likely due to the fact that the dry ground allowed for marginal freeze events to fall into the lower 30s and just touch freezing for brief periods.

 

Table 2

Freeze Events (Overall Rank)

Hard Freeze Events

Lowest Season Temperature

Average # of Freeze Events

Record # of Freeze Events

JAX

28 (6)

4

20

18

37 (1976-77)

GNV

28 (2)

5

21

16

34 (1957-58)

AMG

40 (4)

9

21

25

45 (1977-78)

SSI

10 (19)

1

25

11

26 (1995-96)


The last element of the winter (dry) season was the lack of precipitation through much of the period.  In fact, if it wasn't for a very rainy period that developed in the very last days of March this winter would have gone down as one of the driest on record.  The weak La Nina episode that was ongoing much of the winter did keep precipitation below normal through every month except for March which became wet at the very end as described above, and even with the late season heavy rains, SSI's precipitation total of around 8 inches still ranks as the 3rd driest on record. Table 3 includes the details of the winter precipitation totals across the region.


Table 3

Nov-Mar Precipitation (Inches)

Departure from Normal (Inches)

Seasonal Rank in Overall Driest Winters

JAX

10.38

-5.37

38 out of 138 years

GNV

11.98

-3.91

36 out of 106 years

AMG

16.02

-3.78

23 out of 61 years

SSI

8.24

-8.57

3 out of 61 years


On a final note, in the atmosphere's attempt to reach equilibrium, the 4 to 9 inch below normal rainfall departures listed above were quickly erased by an unprecendented two weeks of heavy rainfall from late March through early April. Some areas of Southeast Georgia received 12 to 18 inches of rainfall to push rivers from near record low levels to major flood status in a matter of days.  Northeast Florida locations received rainfall on the order of 6 to 12 inches and rivers have pushed out of their banks as well.

In summary, the winter of 2008-2009 will go down as one of the coldest in last decade, especially in regards to the number of freeze events.  This was enhanced as discussed above by the below normal precipitation experienced through much of the winter and the colder than normal overnight minimum temperatures. This winter was not without its share of roller coaster weather pattern shifts, from the unseasonably warm December and Christmas to the record breaking rainfall in late March into early April to break the short-term drought situation across Southeast Georgia.

Jason Hess, Meteorologist, NWS Jacksonville


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.