However much to the elation of my southern snow weenies the warm pattern for the GULF COAST states that has allowed me to keep my golden, gorgeous tan flowing through the First week of January is about to come to an END.
First of all WHY has it been so warm in FL? Look no further than the large scale pattern over North America. A strong Omega ridge has been in place near 150 W longitude over the first 5 days of the month. As a result simple wave physics tells us that there MUST be a trough downstream of it over the Western US and yet another ridge amplification over the eastern US in response to that trough. This is called a RNA (or –PNA) pattern.
Here are composite 500mb height anomalies for the first 5 days of JAN in correlation w/ a strongly –PNA / +NAO pattern (PNA < -0.9, NAO > +1.0) and compare that to the first 5 days of this month.
Notice the strong ridge over the central and eastern US. The flow around the ridge has transported warm air northward as evidenced by 850mb temperature anomalies averaged over the first 5 days of the month.
Also b/c of the ridge over the EUS the mean position of the jet the first 5 days has been VERY far to the North---running from the SW us to the Great lakes region and New England keeping MOST of the storminess away from Florida.
Will this last a lot longer? NO…infact it’s coming to an abrupt end by the end of this week as a strong low develops over the Midwest and pushes a cold front across the Gulf coast states. Another wave may try to develop along the front near the East coast, BUT how much of any effect this will have remains to be seen (DON’T trust the GFS for the details on this---its like an ex-wife…starts out great then ends up screwing you in the end).
The low will phase w/ some PJ/AJ energy as it moves into central Canada developing LARGE / COLD PV near Hudson Bay by D5-6, sending a pretty decent arctic outbreak southeastward from the Plains into the OV and EUS D6 and 7.
This as the trough comes back into the EUS and the PNA goes positive.



This pattern change is in response to the latest MJO now approaching the dateline and SHOULD last through the remainder of the month.
Wild card will continue to be the NAO, which if allowed to go STRONGLY negative could force severe amplification of the trough over the EUS and anomalous southward displacement of the PV. IF this were to happen, it would lead to an extremely cold end to the Month across the Northeast; and Snow potential further south given the fact that the storm track would get shoved VERY far to the south.
SO gulf coast, Southeast and FL folks, DON’T fret, the warm pattern is just about GONE. For the time being.