Arctic Air Has Arrived

Arctic Air Has Arrived

  So what happened to the forecast of near to slightly above normal temperatures for this winter? Well as occurred last winter the Arctic Oscillation (AO) has begun to dominate the weather pattern across the U.S. overwhelming the effects of the El Niño Southern Oscillation (El Niño/La Niña). The AO is a short term oscillation on the scale of a few weeks while the ENSO is much longer on the scale of months. The AO has little effect on our weather during the summer months, but during the winter there is a high correlation between it and the temperatures we experience (Figure 2). Therefore, during the winter months the AO can radically change the temperatures across the area causing either much above or much below normal temperatures.  As it turns out the AO went into a highly negative phase back around November 20th and bottomed out around the 27th as seen in the image below (Figure 1). 

    Observed and Forecasts Arctic Oscillation

     Figure 1

   Arctic Oscillation Correlation with temperatures for December through February

Figure 2

  The AO has since recovered back to around neutral, but as is generally the case during the late fall and winter months there is about a 10 to 14 day lag before the effects of the AO are felt here in Florida. Therefore, when the AO goes highly negative we tend to see below normal temperatures within about two weeks or so and when it goes highly positive we see above normal temperatures. So based on this theory we should see closer to normal temperatures return during the middle of December, but if the forecast models are correct (red lines in Figure 1 above) the AO is expected to go highly negative again in the next week or so which would bring more cold weather around and the week after Christmas. More information and graphics about the AO can be found on the Climate Prediction Center web site listed below:  

 http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml

 

  So with this in mind it’s not surprising that another blast of arctic air has moved into the region early this week, about two weeks after the AO bottomed out. During Sunday a deepening mid/upper level trough (Figure 3) pushed a strong cold front across the region. This has been followed by an area of cold Canadian high pressure (Figure 4) that has ushered in the next shot of cold arctic air and is expected to last until about Wednesday night. Temperatures early this week are expected to be about 15 to as much as 30 degrees below normal, or at least as cold as what we saw early last week.

Forecast Upper Level Pattern for December 11 through December 16, 2010

Figure 3: Forecast Mid/Upper Level Pattern with Jetstream in red

             

Forecast Surface Map for December 11 through December 16, 2010

Figure 4: Forecast Surface Map

 

  Brisk northwesterly winds will gradually shift to north and diminish tonight into Tuesday with Small Craft Advisory conditions continuing over the coastal waters into midday Tuesday. Therefore, mariners may want to postpone and/or reschedule trips until winds and seas diminish later Tuesday or Wednesday.

  For tonight into Tuesday morning a Hard Freeze warning is in effect across much of the area from the Nature Coast southward into inland portions of West Central Florida with a Freeze Warning over Southwest Florida as well as along the coast from the Tampa Bay area southward. Low temperatures are forecast to fall to into the upper teens to lower 20s over the Nature Coast and into the mid 20s further south over inland portions of West Central Florida, including 8 to 13 hours of temperatures below freezing. Further south across inland Southwest Florida and near the coast from the Tampa Bay area, southward temperatures are forecast to drop into the upper 20s to lower 30s, including 3 to as much as 8 hours of temperatures below freezing. However, similar to early last week the immediate coastal areas will most likely escape the freezing temperatures, but still fall into the mid 30s to lower 40s. Winds will lighten some tonight away from the coast, but continue between 5 and 10 mph so the threat of frost will remain low, but wind chill values will fall into the teens and 20s across most of the area late tonight into early Tuesday morning.
 
  During Tuesday and Tuesday night winds will continue to diminish as the high pressure moves toward the area with daytime temperatures remaining cool and only climbing into the upper 40s north to mid 50s south. Temperatures Tuesday night are expected to be similar to tonight, but because the winds are forecast to become light a wider range of temperatures will be likely with some of the normally colder inland locations a few degrees colder then tonight.  Also with the lighter winds frost will become a better possibility.

   Finally during Wednesday temperatures will begin to moderate with highs climbing back into the mid 50s to mid 60s. However, the high will remain across the region into Wednesday night so yet another chilly night is expected with a freeze again possible over the Nature Coast and some frost further south into inland portions of West Central Florida.

   Residents of West Central and Southwest Florida should be prepared for the cold weather. These types of severe freezes can pose a significant threat to agriculture, exposed water pipes, such as those at houses on stilts, some trailers, and pipes connected to swimming pools. Residents should be ready to protect vegetation and bring pets indoors each night. Prolonged temperatures near or below freezing may severely damage sensitive vegetation, and can be harmful to pets. If you plan on using space heaters please remember they can be a fire hazard, and you should keep linens, blankets, curtains, and other flammables away from the heater at all times. In addition, if you plan on being outdoors late each night into the early morning hours be sure to bundle up and dress in layers. Stay tuned to NOAA Weather Radio or your local media for the latest information on this cold outbreak.

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  During most other times of this month these forecast cold temperatures would be close to if not new records.  However, during mid-December of 1962 the Florida peninsula was hit by one of the coldest outbreaks on record with widespread low temperatures in the teens as far south as Hillsborough and Polk counties. Thankfully we are not anticipating temperatures this cold so the only locations that will likely see new record temperatures are sites like Archbold Bio Stn and Punta Gorda 4 ESE whose records began after 1962.

Below are tables of the record low temperatures at sites around the area for December 13, 14 and 15, and the record low maximums for December 13 and 14.

RECORD LOWS FOR DECEMBER 13:

LOCATION                       RECORD LOWS  NORMAL   RECORDS
                                FOR DEC 13   LOW      BEGAN

ARCADIA                :ARCF1 **18 IN 1962    51      1899
ARCHBOLD BIO STN       :ACHF1   28 IN 1973    49      1969
AVON PARK 2 W          :AVPF1   20 IN 1962    52      1901
BARTOW                 :BARF1 **18 IN 1962    54      1892
BROOKSVILLE CHIN HILL  :BROF1   15 IN 1962    51      1892
BUSHNELL 2 E           :BSHF1   15 IN 1962    49      1948
CHIEFLAND 5 SE         :CHIF1   13 IN 1962    45      1956
FORT MYERS/PAGE FIELD  :KFMY   *26 IN 1962    56      1902
INVERNESS 3 SE         :INVF1#  20 IN 1957    46      1948
LAKELAND               :LLDF1 **20 IN 1962    53      1948
MOUNTAIN LAKE          :LWLF1   20 IN 1962    51      1935
MYAKKA RIVER ST PARK   :MKCF1 **18 IN 1962    52      1956
PARRISH                :PARF1   20 IN 1962    52      1957
PLANT CITY             :PLCF1   18 IN 1962    52      1892
PUNTA GORDA 4 ESE      :PNTF1   32 IN 1973    54      1965
ST LEO                 :STLF1 **18 IN 1962    50      1895
ST PETE/ALBERT WHITTED :KSPG    22 IN 1962    57      1914
SARASOTA-BRADENTON     :KSRQ    22 IN 1962    53      1911
TAMPA                  :KTPA   *18 IN 1962    55      1890
TARPON SPRINGS         :TRPF1 **19 IN 1962    52      1892
VENICE                 :VNCF1  *22 IN 1962    54      1955
WAUCHULA 2 N           :WAUF1   21 IN 1962    51      1933
WEEKI WACHEE           :WEEF1   28 IN 1995    47      1969
                                    & 1973
WINTER HAVEN           :WHNF1 **19 IN 1962    53      1941

 * LOWEST TEMPERATURE EVER SINCE RECORDS BEGAN
** TIED FOR LOWEST TEMPERATURE EVER SINCE RECORDS BEGAN
 # INVF1 DATA NOT AVAILABLE IN DECEMBER 1962
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RECORD LOWS FOR DECEMBER 14:

LOCATION                       RECORD LOWS  NORMAL   RECORDS
                                FOR DEC 14   LOW      BEGAN

ARCADIA                :ARCF1   20 IN 1962    51      1899
ARCHBOLD BIO STN       :ACHF1   28 IN 1988    49      1969
AVON PARK 2 W          :AVPF1   21 IN 1962    51      1901
BARTOW                 :BARF1   24 IN 1962    54      1892
BROOKSVILLE CHIN HILL  :BROF1   23 IN 1962    51      1892
BUSHNELL 2 E           :BSHF1   17 IN 1962    49      1948
CHIEFLAND 5 SE         :CHIF1   18 IN 1962    45      1956
FORT MYERS/PAGE FIELD  :KFMY    30 IN 1962    56      1902
INVERNESS 3 SE         :INVF1#  29 IN 1988    46      1948
                                    1960 & 1957
LAKELAND               :LLDF1   27 IN 1962    53      1948
MOUNTAIN LAKE          :LWLF1   21 IN 1962    51      1935
MYAKKA RIVER ST PARK   :MKCF1   20 IN 1962    52      1956
PARRISH                :PARF1   23 IN 1962    52      1957
PLANT CITY             :PLCF1   22 IN 1962    52      1892
PUNTA GORDA 4 ESE      :PNTF1   36 IN 1969    54      1965
ST LEO                 :STLF1   25 IN 1962    50      1895
ST PETE/ALBERT WHITTED :KSPG    32 IN 1962    56      1914
SARASOTA-BRADENTON     :KSRQ    23 IN 1962    53      1911
TAMPA                  :KTPA    28 IN 1962    55      1890
TARPON SPRINGS         :TRPF1   19 IN 1962    52      1892
VENICE                 :VNCF1   26 IN 1962    54      1955
WAUCHULA 2 N           :WAUF1   24 IN 1962    51      1933
WEEKI WACHEE           :WEEF1   27 IN 1988    47      1969
WINTER HAVEN           :WHNF1   22 IN 1962    53      1941

# INVF1 DATA NOT AVAILABLE IN DECEMBER 1962

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RECORD LOWS FOR DECEMBER 15:

LOCATION                       RECORD LOWS  NORMAL   RECORDS
                                FOR DEC 15   LOW      BEGAN

ARCADIA                :ARCF1   28 IN 1944    51      1899
ARCHBOLD BIO STN       :ACHF1   35 IN 1980    49      1969
AVON PARK 2 W          :AVPF1   31 IN 1962    51      1901
BARTOW                 :BARF1   26 IN 1915    53      1892
BROOKSVILLE CHIN HILL  :BROF1   28 IN 2004    50      1892
BUSHNELL 2 E           :BSHF1   25 IN 1962    49      1948
CHIEFLAND 5 SE         :CHIF1   25 IN 1962    45      1956
FORT MYERS/PAGE FIELD  :KFMY    33 IN 1944    56      1902
INVERNESS 3 SE         :INVF1#  29 IN 1988    46      1948
LAKELAND               :LLDF1   31 IN 2004    53      1948
MOUNTAIN LAKE          :LWLF1   25 IN 1944    51      1935
MYAKKA RIVER ST PARK   :MKCF1   27 IN 1962    52      1956
PARRISH                :PARF1   32 IN 1962    52      1957
PLANT CITY             :PLCF1   25 IN 1944    51      1892
PUNTA GORDA 4 ESE      :PNTF1   35 IN 2004    54      1965
                                    & 1966
ST LEO                 :STLF1   30 IN 1944    50      1895
ST PETE/ALBERT WHITTED :KSPG    37 IN 1944    56      1914
SARASOTA-BRADENTON     :KSRQ    31 IN 1915    53      1911
TAMPA                  :KTPA    33 IN 1968    55      1890
                                   1966 & 1944
TARPON SPRINGS         :TRPF1   27 IN 1962    52      1892
VENICE                 :VNCF1   35 IN 2004    54      1955
WAUCHULA 2 N           :WAUF1   23 IN 1944    51      1933
WEEKI WACHEE           :WEEF1   30 IN 2004    47      1969
WINTER HAVEN           :WHNF1   28 IN 1962    53      1941

# INVF1 DATA NOT AVAILABLE IN DECEMBER 1962

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RECORD LOW MAXIMUMS FOR DECEMBER 13:

                                RECORD LOW
LOCATION                         MAXIMUMS   NORMAL   RECORDS
                                FOR DEC 13   HIGH     BEGAN

ARCADIA                :ARCF1   51 IN 1962    74      1899
ARCHBOLD BIO STN       :ACHF1   63 IN 1993    76      1969
AVON PARK 2 W          :AVPF1   49 IN 1962    74      1901
BARTOW                 :BARF1   45 IN 1962    75      1892
BROOKSVILLE CHIN HILL  :BROF1   43 IN 1962    72      1892
BUSHNELL 2 E           :BSHF1   43 IN 1962    73      1948
CHIEFLAND 5 SE         :CHIF1   38 IN 1962    70      1956
FORT MYERS/PAGE FIELD  :KFMY    50 IN 1962    77      1902
INVERNESS 3 SE         :INVF1   55 IN 1960    72      1948
LAKELAND               :LLDF1   44 IN 1962    75      1948
MOUNTAIN LAKE          :LWLF1   46 IN 1962    73      1935
MYAKKA RIVER ST PARK   :MKCF1   51 IN 1962    76      1956
                                    & 1957
PARRISH                :PARF1   47 IN 1962    74      1957
PLANT CITY             :PLCF1   47 IN 1962    74      1892
PUNTA GORDA 4 ESE      :PNTF1   58 IN 1969    76      1965
ST LEO                 :STLF1   45 IN 1962    74      1895
ST PETE/ALBERT WHITTED :KSPG    42 IN 1962    71      1914
SARASOTA-BRADENTON     :KSRQ    47 IN 1962    74      1911
TAMPA                  :KTPA    44 IN 1962    72      1890
TARPON SPRINGS         :TRPF1   42 IN 1957    74      1892
VENICE                 :VNCF1   48 IN 1962    74      1955
WAUCHULA 2 N           :WAUF1   47 IN 1962    74      1933
WEEKI WACHEE           :WEEF1   58 IN 1969    72      1969
WINTER HAVEN           :WHNF1   46 IN 1957    74      1941

# INVF1 DATA NOT AVAILABLE IN DECEMBER 1962

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RECORD LOW MAXIMUMS DECEMBER 14:

                                RECORD LOW
LOCATION                         MAXIMUMS   NORMAL   RECORDS
                                FOR DEC 14   HIGH     BEGAN

ARCADIA                :ARCF1   59 IN 1989    74      1899
ARCHBOLD BIO STN       :ACHF1   60 IN 1969    76      1969
AVON PARK 2 W          :AVPF1   58 IN 1952    74      1901
BARTOW                 :BARF1   54 IN 1895    75      1892
BROOKSVILLE CHIN HILL  :BROF1   50 IN 1914    72      1892
BUSHNELL 2 E           :BSHF1   55 IN 1962    72      1948
                                    & 1952
CHIEFLAND 5 SE         :CHIF1   55 IN 1962    70      1956
FORT MYERS/PAGE FIELD  :KFMY    59 IN 1962    77      1902
INVERNESS 3 SE         :INVF1   57 IN 1989    72      1948
                                   1988 & 1952
LAKELAND               :LLDF1   53 IN 1962    75      1948
MOUNTAIN LAKE          :LWLF1   56 IN 1962    73      1935
MYAKKA RIVER ST PARK   :MKCF1   55 IN 1960    76      1956
PARRISH                :PARF1   56 IN 1988    74      1957
PLANT CITY             :PLCF1   57 IN 1962    74      1892
                                    & 1935
PUNTA GORDA 4 ESE      :PNTF1   60 IN 1969    76      1965
ST LEO                 :STLF1   53 IN 1952    74      1895
ST PETE/ALBERT WHITTED :KSPG    52 IN 1962    71      1914
SARASOTA-BRADENTON     :KSRQ    59 IN 1962    74      1911
TAMPA                  :KTPA    53 IN 1962    72      1890
TARPON SPRINGS         :TRPF1   52 IN 1895    74      1892
VENICE                 :VNCF1   58 IN 1962    74      1955
WAUCHULA 2 N           :WAUF1   57 IN 1952    74      1933
WEEKI WACHEE           :WEEF1   56 IN 1989    72      1969
WINTER HAVEN           :WHNF1   58 IN 1962    74      1941

# INVF1 DATA NOT AVAILABLE IN DECEMBER 1962

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For more local climate information, please visit our web page at

  http://weather.gov/tampabay  

and click on the "Local" link under the Climate subsection on the left side of the page.

$$

PRC

 



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