After Minchoh
1. In a regular year [when Purim doesn’t fall on a Friday], the minhag is to make the Purim seudoh after minchoh (רמ"א סי' תרצ"ה ס"ב ). Like the other mitzvos of the day, the Purim seudoh should technically be in the morning, but people are generally busy with mishloach monos (תרומת הדשן ) until the zman for minchoh, at which time one may not begin a seudoh before davening (הגר"א, מ"ב סק"ח ). This is also true during the half hour before minchoh gedoloh (שו"ע סי' רל"ב ס"ב ), i.e., from chatzos and on (מ"ב שם סק"ז ).
2. One should daven minchoh with plenty of time left in the day so he will be able to begin his seudoh afterward and still have most of the seudoh by day. One should not begin close to the evening, having his seudoh mainly on the night of the 15th (רמ"א ).
3. Starting by day, continuing into the night. Although one should start his seudoh by day, there are gedolim and tzaddikim who continue their seudoh into the night of the 15th (משמרת שלום סי' נ' סק"ה ), as there is also significance to rejoicing on the night of the 15th [Shushan Purim].
4. In Yerushalayim. Some other reasons given for extending the seudoh into the night: the theme of cursing Homon extends into the night since, for non-Jews, the night follows the day (דרשות חת"ס השלם, דרוש ט"ו עמ' תקע"ז ); wiping out Amoleik, i.e., spilling the blood of the wicked, is like a korban. Regarding korbanos, the night follows the day (שפתי צדיק בשם החי' הרי"ם ).
Morning Seudoh
5. It is best to make the seudoh in the morning (א"ר ופמ"ג ומ"ב בשם השל"ה ). This has Kabbalistic significance (כף החיים סקכ"ג בשם הרש"ש ). Thus, if one has the ability and the time, he should also wash for a seudoh on Purim morning (ליקוטי מהרי"ח ). However, some fulfill the minhag to have this seudoh with milchige foods and cheese, which the Torah, which was reaccepted in the days of Achashveirosh, is likened to (אור"ח ספינקא סק"ד בשם ס' יפה ללב ).
6. Therefore, one may certainly fulfill the mitzvoh of mishloach monos by sending a milchige mishloach monos at the beginning of the day, even according to the opinion that mishloach monos is for the seudoh [referred to as ‘Reason 1’ in Chukai Chaim, Issue 79, paragraph 2], since it can be eaten at the morning seudoh.
