Wet July's And Tropical Cyclone Landfalls

[Ptarmigan]

This wet July has me wondering if there a relationship with wet July's and tropical cyclones making landfall on the Upper Texas Coast. The last time we had a wet July was in 2007. August to September saw Tropical Storm Erin and Hurricane Humberto make landfall. All rainfall data is Upper Texas Coast rainfall from 1895-2010.

Tropical Cyclone Landfall Overall

Code: Select all

Top 20 Wettest For Upper Texas Coast
1979	 14.06	        1*
2007	 13.72	        2*
1933	 11.87	        3*
1942	 11.82	        4*
1903	 11.42	        5
2010	 10.75	        6
2006	 10.63	        7
1902	  9.70	        8*
1900	  9.57	        9*
1943	  9.24	       10
1983	  9.06	       11*
1939	  8.85	       12
1936	  7.97	       13
1919	  7.88	       14
1941	  7.61	       15*
1961	  7.55	       16*
1976	  7.51	       17
1959	  7.46	       18
1908	  7.31	       19
1916	  6.94	       20

*Tropical Cyclone Landfalls August to October.

9 of the 20 wettest July's saw something make landfall from August to October.


Hurricane Landfall Overall

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Top 20 Wettest For Upper Texas Coast
1979	 14.06	        1
2007	 13.72	        2*
1933	 11.87	        3
1942	 11.82	        4*
1903	 11.42	        5
2010	 10.75	        6
2006	 10.63	        7
1902	  9.70	        8*
1900	  9.57	        9*
1943	  9.24	       10
1983	  9.06	       11*
1939	  8.85	       12
1936	  7.97	       13
1919	  7.88	       14
1941	  7.61	       15*
1961	  7.55	       16*
1976	  7.51	       17
1959	  7.46	       18
1908	  7.31	       19
1916	  6.94	       20

*Hurricane Landfalls August to October.

7 of the 20 wettest July's saw hurricane make landfall from August to October.


Major Hurricane Landfall Overall

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Top 20 Wettest For Upper Texas Coast
1979	 14.06	        1
2007	 13.72	        2
1933	 11.87	        3
1942	 11.82	        4*
1903	 11.42	        5
2010	 10.75	        6
2006	 10.63	        7
1902	  9.70	        8
1900	  9.57	        9*
1943	  9.24	       10
1983	  9.06	       11*
1939	  8.85	       12
1936	  7.97	       13
1919	  7.88	       14
1941	  7.61	       15*
1961	  7.55	       16*
1976	  7.51	       17
1959	  7.46	       18
1908	  7.31	       19
1916	  6.94	       20

*Major Hurricane Landfalls August to October.

5 of the 20 wettest July's saw major hurricane make landfall from August to October.


Now, let's look at dry July's.

Tropical Cyclone Landfall Overall

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Top 20 Driest July
1899/1924  .00	      1
1925	   .74	      2
1930	   .81	      3
2000	   .89	      4
1986	  1.00	      5
1993	  1.09	      6
1956	  1.15	      7
1898	  1.16	      8*
1918	  1.18	      9*
1895	  1.23	      10*
1962	  1.25	      11
1914	  1.33	      12
1957	  1.34	      13*
1897	  1.41	      14*
1944	  1.44	      15
1994	  1.47	      16
1947	  1.68	      17*
1982	  1.75	      18*
1996	  1.83	      19
1971	  1.85	      20*

*Tropical Cyclone Landfalls August to October.

8 of the 20 driest July's saw something make landfall from August to October.

Hurricane Landfall Overall

Code: Select all

Top 20 Driest July
1899/1924  .00	      1
1925	   .74	      2
1930	   .81	      3
2000	   .89	      4
1986	  1.00	      5
1993	  1.09	      6
1956	  1.15	      7
1898	  1.16	      8
1918	  1.18	      9*
1895	  1.23	      10
1962	  1.25	      11
1914	  1.33	      12
1957	  1.34	      13
1897	  1.41	      14*
1944	  1.44	      15
1994	  1.47	      16
1947	  1.68	      17
1982	  1.75	      18
1996	  1.83	      19
1971	  1.85	      20*

*Hurricane Landfalls August to October.

3 of the 20 driest July's saw hurricane make landfall from August to October.


Tropical Cyclone Landfall Overall

Code: Select all

Top 20 Driest July
1899/1924  .00	      1
1925	   .74	      2
1930	   .81	      3
2000	   .89	      4
1986	  1.00	      5
1993	  1.09	      6
1956	  1.15	      7
1898	  1.16	      8
1918	  1.18	      9*
1895	  1.23	      10
1962	  1.25	      11
1914	  1.33	      12
1957	  1.34	      13
1897	  1.41	      14
1944	  1.44	      15
1994	  1.47	      16
1947	  1.68	      17
1982	  1.75	      18
1996	  1.83	      19
1971	  1.85	      20

*Major Hurricane Landfalls August to October.

1 of the 20 driest July's saw major hurricane make landfall from August to October.

Does this mean we are at risk for this season, since July 2010 is the 6th wettest July on record from 1895-2010 for the Upper Texas Coast? More than likely we are at risk for something tropical to hit the Upper Texas Coast. Notice that with the top 20 driest, only one major hurricane made landfall after July, 1918. On the other hand, 5 major hurricanes made landfall after July in the wettest July on record. 5 out of 11 major hurricanes have been recorded to make landfall on the Upper Texas Coast from 1895 to 2010. Compare this to 1 out of 11 major hurricanes that made landfall from August to October in dry July's from 1895 to 2010. There is a total of 12 major hurricane landfalls from 1895 to 2010, which includes a July 1909 Velasco Hurricane. Major hurricanes make landfall on the Upper Texas Coast from August to October. That leaves 5 that fell outside of the top 20 wettest and driest July's on record. Ike in 2008 fell in a somewhat average July. The Great Galveston Hurricane of 1900 fell in one of the wettest July's on record.

Source for the rainfall data.
http://www7.ncdc.noaa.gov/CDO/CDODivisionalSelect.jsp

A correlation chart will be coming soon.

[Ptarmigan]

Scatter Plots









Correlation Value


The correlation for major hurricane and July landfall is a positive correlation, which means a wetter July. The lower the p-value, the more significant it is. The p-value for July rainfall and major hurricane is below 0.01, so there is a significant correlation between July rainfall and major hurricane making landfall. Does it mean all wet July's are at risk for any tropical cyclone landfall including major hurricanes, No, but it does certainly increases the risk of seeing one.

[srainhoutx]

This is why you are our Stats guy Ptarmigan . Good Job! The numbers are hard to ignore.

[Ptarmigan]

This is why you are our Stats guy Ptarmigan . Good Job! The numbers are hard to ignore.

Thanks. July is the make it and break it for tropical cyclone activity for our area.